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Sample records for stable complexation ratio

  1. Net Stable Funding Ratio: Impact on Funding Value Adjustment

    OpenAIRE

    Siadat, Medya; Hammarlid, Ola

    2017-01-01

    In this paper we investigate the relationship between Funding Value Adjustment (FVA) and Net Stable Funding Ratio (NSFR). FVA is defined in a consistent way with NSFR such that the new framework of FVA monitors the costs due to keeping NSFR at an acceptable level, as well. In addition, the problem of choosing the optimal funding strategy is formulated as a shortest path problem where the proposed FVA framework is applied in the optimization process. The solution provides us with the optimal f...

  2. Stable isotope ratios in hair and teeth reflect biologic rhythms.

    Directory of Open Access Journals (Sweden)

    Otto Appenzeller

    Full Text Available Biologic rhythms give insight into normal physiology and disease. They can be used as biomarkers for neuronal degenerations. We present a diverse data set to show that hair and teeth contain an extended record of biologic rhythms, and that analysis of these tissues could yield signals of neurodegenerations. We examined hair from mummified humans from South America, extinct mammals and modern animals and people, both healthy and diseased, and teeth of hominins. We also monitored heart-rate variability, a measure of a biologic rhythm, in some living subjects and analyzed it using power spectra. The samples were examined to determine variations in stable isotope ratios along the length of the hair and across growth-lines of the enamel in teeth. We found recurring circa-annual periods of slow and fast rhythms in hydrogen isotope ratios in hair and carbon and oxygen isotope ratios in teeth. The power spectra contained slow and fast frequency power, matching, in terms of normalized frequency, the spectra of heart rate variability found in our living subjects. Analysis of the power spectra of hydrogen isotope ratios in hair from a patient with neurodegeneration revealed the same spectral features seen in the patient's heart-rate variability. Our study shows that spectral analysis of stable isotope ratios in readily available tissues such as hair could become a powerful diagnostic tool when effective treatments and neuroprotective drugs for neurodegenerative diseases become available. It also suggests that similar analyses of archaeological specimens could give insight into the physiology of ancient people and animals.

  3. Heavy element stable isotope ratios. Analytical approaches and applications

    International Nuclear Information System (INIS)

    Tanimizu, Masaharu; Sohrin, Yoshiki; Hirata, Takafumi

    2013-01-01

    Continuous developments in inorganic mass spectrometry techniques, including a combination of an inductively coupled plasma ion source and a magnetic sector-based mass spectrometer equipped with a multiple-collector array, have revolutionized the precision of isotope ratio measurements, and applications of inorganic mass spectrometry for biochemistry, geochemistry, and marine chemistry are beginning to appear on the horizon. Series of pioneering studies have revealed that natural stable isotope fractionations of many elements heavier than S (e.g., Fe, Cu, Zn, Sr, Ce, Nd, Mo, Cd, W, Tl, and U) are common on Earth, and it had been widely recognized that most physicochemical reactions or biochemical processes induce mass-dependent isotope fractionation. The variations in isotope ratios of the heavy elements can provide new insights into past and present biochemical and geochemical processes. To achieve this, the analytical community is actively solving problems such as spectral interference, mass discrimination drift, chemical separation and purification, and reduction of the contamination of analytes. This article describes data calibration and standardization protocols to allow interlaboratory comparisons or to maintain traceability of data, and basic principles of isotope fractionation in nature, together with high-selectivity and high-yield chemical separation and purification techniques for stable isotope studies.

  4. Stable strontium isotopic ratios from archaeological organic remains from the Thorsberg peat bog

    DEFF Research Database (Denmark)

    Nosch, Marie-Louise Bech; von Carnap-Bornheim, Claus; Grupe, Gisela

    2007-01-01

    Pilot study analysing stable strontium isotopic ratios from Iron Age textile and leather finds from the Thorsberg peat bog.......Pilot study analysing stable strontium isotopic ratios from Iron Age textile and leather finds from the Thorsberg peat bog....

  5. On the classification of complex vector bundles of stable rank

    Indian Academy of Sciences (India)

    , the tuples of cohomology classes on a compact, complex manifold, corresponding to the Chern classes of a complex vector bundle of stable rank. This classification becomes more effective on generalized flag manifolds, where the Lie ...

  6. The use of carbon stable isotope ratios in drugs characterization

    Energy Technology Data Exchange (ETDEWEB)

    Magdas, D. A., E-mail: gabriela.cristea@itim-cj.ro; Cristea, G., E-mail: gabriela.cristea@itim-cj.ro; Bot, A., E-mail: gabriela.cristea@itim-cj.ro; Mirel, V., E-mail: gabriela.cristea@itim-cj.ro [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath Str., 400293 Cluj-Napoca (Romania)

    2013-11-13

    Isotopic Ratio Mass Spectrometry (IRMS) is an effective toll to be used for drug product authentication. The isotopic composition could be used to assist in the differentiation between batches of drugs and assist in the identification of counterfeit materials on the market. Only two factors affect the isotopic ratios in pharmaceutical components: the isotopic composition of the raw materials and the synthetic processes performed upon them. Counterfeiting of pharmaceutical drugs threatens consumer confidence in drug products companies' economical well-being. In this preliminary study, the analyzed samples consist in two types of commercially available analgesics, which were purchases from Romanian pharmacies. Differences in δ{sup 13}C between batches from −29.7 to −31.6% were observed, demonstrating that this method can be used to differentiate among individual drug batches and subsequently identify counterfeits on the market. On the other hand, carbon isotopic ratios differences among producers were recorded, the variations being between −31.3 to −34.9% for the same type of analgesic, but from different manufactures.

  7. Jealousy Graphs: Structure and Complexity of Decentralized Stable Matching

    Science.gov (United States)

    2013-01-01

    REPORT Jealousy Graphs: Structure and Complexity of Decentralized Stable Matching 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: The stable matching...Franceschetti 858-822-2284 3. DATES COVERED (From - To) Standard Form 298 (Rev 8/98) Prescribed by ANSI Std. Z39.18 - Jealousy Graphs: Structure and...market. Using this structure, we are able to provide a ner analysis of the complexity of a subclass of decentralized matching markets. Jealousy

  8. Stable isotope ratio determination of the origin of vanillin in vanilla extracts and its relationship to vanillin/potassium ratios

    International Nuclear Information System (INIS)

    Martin, G.E.; Alfonso, F.C.; Figert, D.M.; Burggraff, J.M.

    1981-01-01

    A method is described for isolating vanillin from vanilla extract, followed by stable isotope ratio analysis to determine the amount of natural vanillin contained in adulterated vanilla extracts. After the potassium content is determined, the percent Madagascar and/or Java vanilla beans incorporated into the extract may then be approximated from the vanillin/potassium ratio

  9. Applications of stable Isotope ratios determinations in fruit juice authentication

    International Nuclear Information System (INIS)

    Magdas, Dana Alina; Dehelean, Adriana; Voica, Cezara; Puscas, Romulus

    2010-01-01

    Full text: Adulteration of a product consists in making it impure by fraudulent addition of a foreign or inferior substance. The result is either an alteration of the product and of its quality or a falsification. The falsification is a voluntary act with the intention of abuse. The falsification may be more or less sophisticated and its sophistication as well as its costs increases with the improvement of analytical methods. Vacuum concentration with aroma does not affect the chemical composition of fruit juices and therefore the determination of deuterium (D) and oxygen-18 content in waters is the most confident procedure for differentiating between a natural single strength juice and a juice rediluted from a concentrate. This technique is based on the fact that when absorbed by a plant, the rainwater or the irrigation water is fractionated by evapotranspiration, and enriched in the heavy isotopes (deuterium and oxygen-18) with respect to the light isotope (hydrogen and oxygen-16, respectively). It is known that climatic conditions affect the isotope content of rain waters and therefore that of fruit juices waters: the warmer climate, the higher the deuterium and oxygen-18 contents in water. Rainwater and tap water have nearly the same isotopic content and the water of fruit juices derived from concentrate by dilution with tap water has an isotopic content close to that of tap water. This makes it easy to distinguish diluted concentrates from the isotopically more enriched water of authentic single strength juice. In this study, single strength juice, in Romanian fruits, were investigated by mean of stable isotope measurements (oxygen, hydrogen and carbon) in order to offer a discussion basis for the authenticity of some fruit juices currently available on Romanian market. (authors)

  10. Forensic Applications of Light-Element Stable Isotope Ratios of Ricinus communis Seeds and Ricin Preparations

    Energy Technology Data Exchange (ETDEWEB)

    Kreuzer, Helen W.; West, Jason B.; Ehleringer, James

    2013-01-01

    Seeds of the castor plant Ricinus communis, also known as castor beans, are of forensic interest because they are the source of the poison ricin. We have tested whether stable isotope ratios of castor seeds and ricin prepared by various methods can be used as a forensic signature. We collected over 300 castor seed samples from locations around the world and measured the C, N, O, and H stable isotope ratios of the whole seeds, oil, and three types of ricin preparations. Our results demonstrate that N isotope ratios can be used to correlate ricin prepared by any of these methods to source seeds. Further, stable isotope ratios distinguished >99% of crude and purified ricin protein samples in pair-wise comparison tests. Stable isotope ratios therefore constitute a valuable forensic signature for ricin preparations.

  11. Platinum stable isotope ratio measurements by double-spike multiple collector ICPMS

    DEFF Research Database (Denmark)

    Creech, John; Baker, Joel; Handler, Monica

    2013-01-01

    We present a new technique for the precise determination of platinum (Pt) stable isotope ratios by multiple-collector inductively coupled plasma mass spectrometry (MC-ICPMS) using two different Pt double-spikes ( Pt-Pt and Pt-Pt). Results are expressed relative to the IRMM-010 Pt isotope standard......) can be obtained on Pt stable isotope ratios with either double-spike. Elemental doping tests reveal that double-spike corrected Pt stable isotope ratios are insensitive to the presence of relatively high (up to 10%) levels of matrix elements, although the Pt-Pt double-spike is affected by an isobaric...... = 7.308%) results in a redefined Pt atomic weight of 195.08395 ± 0.00068. Using our technique we have measured small, reproducible and statistically significant offsets in Pt stable isotope ratios between different Pt element standards and the IRMM-010 standard, which potentially indicates...

  12. Insights into Wilson's Warbler migration from analyses of hydrogen stable-isotope ratios

    Science.gov (United States)

    Jeffrey F. Kelly; Viorel Atudorei; Zachary D. Sharp; Deborah M. Finch

    2002-01-01

    Our ability to link the breeding locations of individual passerines to migration stopover sites and wintering locations is limited. Stable isotopes of hydrogen contained in bird feathers have recently shown potential in this regard. We measured hydrogen stable-isotope ratios (deltaD) of feathers from breeding, migrating, and wintering Wilson's Warblers. Analyses...

  13. Symmetric and Asymmetric Tendencies in Stable Complex Systems.

    Science.gov (United States)

    Tan, James P L

    2016-08-22

    A commonly used approach to study stability in a complex system is by analyzing the Jacobian matrix at an equilibrium point of a dynamical system. The equilibrium point is stable if all eigenvalues have negative real parts. Here, by obtaining eigenvalue bounds of the Jacobian, we show that stable complex systems will favor mutualistic and competitive relationships that are asymmetrical (non-reciprocative) and trophic relationships that are symmetrical (reciprocative). Additionally, we define a measure called the interdependence diversity that quantifies how distributed the dependencies are between the dynamical variables in the system. We find that increasing interdependence diversity has a destabilizing effect on the equilibrium point, and the effect is greater for trophic relationships than for mutualistic and competitive relationships. These predictions are consistent with empirical observations in ecology. More importantly, our findings suggest stabilization algorithms that can apply very generally to a variety of complex systems.

  14. Stable isotope ratio measurements in hydrogen, nitrogen, and oxygen using Raman scattering

    International Nuclear Information System (INIS)

    Harney, R.C.; Bloom, S.D.; Milanovich, F.P.

    1975-01-01

    A method for measuring stable isotope ratios using laser Raman scattering was developed which may prove of significant utility and benefit in stable isotope tracer studies. Crude isotope ratio measurements obtained with a low-power laser indicate that with current technology it should be possible to construct an isotope ratio measurement system using laser Raman scattering that is capable of performing 0.1 percent accuracy isotope ratio measurements of 16 O/ 18 O in natural abundance oxygen gas or 14 N/ 15 N in natural abundance nitrogen gas in times less than two minutes per sample. Theory pertinent to the technique, designs of specific isotope ratio spectrometer systems, and data relating to isotope ratio measurements in hydrogen, nitrogen, and oxygen are presented. In addition, the current status of several studies utilizing this technique is discussed. (auth)

  15. Phase behaviour and structure of stable complexes of oppositely charged polyelectrolytes

    Science.gov (United States)

    Mengarelli, V.; Auvray, L.; Zeghal, M.

    2009-03-01

    We study the formation and structure of stable electrostatic complexes between oppositely charged polyelectrolytes, a long polymethacrylic acid and a shorter polyethylenimine, at low pH, where the polyacid is weakly charged. We explore the phase diagram as a function of the charge and concentration ratio of the constituents. In agreement with theory, turbidity and ζ potential measurements show two distinct regimes of weak and strong complexation, which appear successively as the pH is increased and are separated by a well-defined limit. Weak complexes observed by neutron scattering and contrast matching have an open, non-compact structure, while strong complexes are condensed.

  16. Stable isotope ratio mass spectrometry in forensic science and food adulteration research

    International Nuclear Information System (INIS)

    Kumar, B.

    2009-01-01

    Stable Isotope Ratio Mass Spectrometry (SIRMS) is an established technique for the determination of origin of geological, biological, chemical and physio-chemical samples/materials. With the development of highly precise mass spectrometers, the stable isotope ratio determination of hydrogen, carbon, nitrogen and oxygen have gained considerable interest in the fields of forensic science and food authentication. Natural variations in the isotopic composition of lighter elements occur due to fractionation effects, resulting in the finger printing of specific isotope ratio values that are characteristic of the origin, purity, and manufacturing processes of the products and their constituents. Forensic science uses scientific and technical methods to investigate traceable evidence of criminal acts. Stable isotope ratio mass spectrometry has been applied to numerous aspects of the forensic science. The analysis of explosives such as ammonium nitrate, gun powder and tri-nitro-toluene (TNT), cases of murder, armed robbery, drug smuggling, terrorism, arson and hit and run traffic accidents are a few of them. The main types of geological evidences in such cases are mud, soil, rocks, sand, gravel, dust particles, biological materials, organic particles and anthropogenic components. Stable isotopes are used as tools to corroborate and confirm the evidential leads in the investigation of such crimes. The variation in natural abundances of carbon and nitrogen and their isotopic ratios δ 13 C and δ 15 N can identify links between items found at crime scene with those of suspect. The paper discusses the applications of SIRMS in the field of forensic science and food adulteration research

  17. Influence of forest disturbance on stable nitrogen isotope ratios in soil and vegetation profiles

    Science.gov (United States)

    Jennifer D. Knoepp; Scott R. Taylor; Lindsay R. Boring; Chelcy F. Miniat

    2015-01-01

    Soil and plant stable nitrogen isotope ratios (15 N) are influenced by atmospheric nitrogen (N) inputs and processes that regulate organic matter (OM) transformation and N cycling. The resulting 15N patterns may be useful for discerning ecosystem differences in N cycling. We studied two ecosystems; longleaf pine wiregrass (...

  18. Seasonal Sex Ratio Trend in the European Kestrel : An Evolutionarily Stable Strategy Analysis

    NARCIS (Netherlands)

    Pen, I.R.; Weissing, F.J.; Daan, S.

    We present an evolutionarily stable strategy (ESS) model to analyze selection on seasonal variation in the brood sex ratio, as observed in several species of raptorial birds. The model is specifically tailored to the life history of the European kestrel, and it reflects the maturation time

  19. Protein Stable Isotope Fingerprinting (P-SIF): Multidimensional Protein Chromatography Coupled to Stable Isotope-Ratio Mass Spectrometry

    Science.gov (United States)

    Pearson, A.; Bovee, R. J.; Mohr, W.; Tang, T.

    2012-12-01

    As metagenomics increases our insight into microbial community diversity and metabolic potential, new approaches are required to determine the biogeochemical expression of this potential within ecosystems. Because stable isotopic analysis of the major bioactive elements (C, N) has been used historically to map flows of substrates and energy among macroscopic food webs, similar principles may apply to microbes. To address this challenge, we have developed a new analytical approach called Protein Stable Isotope Fingerprinting (P-SIF). P-SIF generates natural stable isotopic fingerprints of microbial individual or community proteomes. The main advantage of P-SIF is the potential to bridge the gap between diversity and function, thereby providing a window into the "black box" of environmental microbiology and helping to decipher the roles of uncultivated species. Our method implements a three-way, orthogonal scheme to separate mixtures of whole proteins into subfractions dominated by single or closely-related proteins. Protein extracts first are isoelectrically focused in a gel-free technique that yields 12 fractions separated over a gradient of pH 3-10. Each fraction then is separated by size-exclusion chromatography into 20 pools, ranging from >100kD to ~10kD. Finally, each of these pools is subjected to HPLC and collected in 40 time-slices based on protein hydrophobicity. Theoretical calculation reveals that the true chromatographic resolution of the total scheme is 5000, somewhat less than the 9600 resulting fractions. High-yielding fractions are subjected to δ13C analysis by spooling-wire microcombustion irMS (SWiM-irMS) optimized for samples containing 1-5 nmol carbon. Here we will present the method, results for a variety of pure cultures, and preliminary data for a sample of mixed environmental proteins. The data show the promise of this method for unraveling the metabolic complexity hidden within microbial communities.

  20. Stable carbon and nitrogen isotope ratios of sodium and potassium cyanide as a forensic signature.

    Science.gov (United States)

    Kreuzer, Helen W; Horita, Juske; Moran, James J; Tomkins, Bruce A; Janszen, Derek B; Carman, April

    2012-01-01

    Sodium and potassium cyanide are highly toxic, produced in large amounts by the chemical industry, and linked to numerous high-profile crimes. The U.S. Centers for Disease Control and Prevention has identified cyanide as one of the most probable agents to be used in a chemical terrorism event. We investigated whether stable C and N isotopic content of sodium and potassium cyanide could serve as a forensic signature for sample matching, using a collection of 65 cyanide samples. Upon analysis, a few of the cyanide samples displayed nonhomogeneous isotopic content associated with degradation to a carbonate salt and loss of hydrogen cyanide. Most samples had highly reproducible isotope content. Of the 65 cyanide samples, >95% could be properly matched based on C and N isotope ratios, with a false match rate <3%. These results suggest that stable C and N isotope ratios are a useful forensic signature for matching cyanide samples. © 2011 American Academy of Forensic Sciences.

  1. Estimation of stability of polynuclear rare earth complexes with EDTA in the presence of stable monocomplexonates

    International Nuclear Information System (INIS)

    Le Ba Tkhun; Kupriyanova, G.N.; Smirnova, N.S.; Martynenko, L.I.; Evseeva, A.M.

    1987-01-01

    Complexing in rare-earth-EDTA system at the mole ratio making up (M 3+ ):(H 2 A 2- )=1:1, 2:1, 5:1, (M=Nd, Yb), C H 2 A 2- =0.010, 0.015 mol/l, μ=0.5 (KCl) is studied in pH 1.6-3.0 interval by pH-metric titration technique using mathematical modelling method. A model containing MA - , MHA, M 2 A 2+ complexes for which stability constants, equalling respectively (lgK) to 15.66, 2.11, 1.06 (for neodymium complexes) and 18.70, 1.78, 0.45 (for ytterbium complexes) are determined by non-linear LSF, appears to be adequate. It is shown that binuclear complex concentration in solution with M 3+ excess is comparable to stable monocomplexonate concentration

  2. The metallic ratios as limits of complex valued transformations

    International Nuclear Information System (INIS)

    Falcon, Sergio; Plaza, Angel

    2009-01-01

    We study the presence of the metallic ratios as limits of two complex valued transformations. These complex variable functions are introduced and related with the two geometric antecedents for each triangle in a particular triangle partition, the four-triangle longest-edge (4TLE) partition. In this way, the fractality of a geometric diagram for the classes of dissimilar generated triangles is also explained.

  3. Method for determination of stable carbon isotope ratio of methylnitrophenols in atmospheric particulate matter

    Directory of Open Access Journals (Sweden)

    S. Moukhtar

    2011-11-01

    Full Text Available A technique for the measurement of the stable isotope ratio of methylnitrophenols in atmospheric particulate matter is presented. Atmospheric samples from rural and suburban areas were collected for evaluation of the procedure. Particulate matter was collected on quartz fibre filters using dichotomous high volume air samplers. Methylnitrophenols were extracted from the filters using acetonitrile. The sample was then purified using a combination of high-performance liquid chromatography and solid phase extraction. The final solution was then divided into two aliquots. To one aliquot, a derivatising agent, Bis(trimethylsilyltrifluoroacetamide, was added for Gas Chromatography-Mass Spectrometry analysis. The second half of the sample was stored in a refrigerator. For samples with concentrations exceeding 1 ng μl−1, the second half of the sample was used for measurement of stable carbon isotope ratios by Gas Chromatography-Isotope Ratio Mass Spectrometry.

    The procedure described in this paper provides a method for the analysis of methylnitrophenols in atmospheric particulate matter at concentrations as low as 0.3 pg m−3 and for stable isotope ratios with an accuracy of better than ±0.5‰ for concentrations exceeding 100 pg m−3.

    In all atmospheric particulate matter samples analysed, 2-methyl-4-nitrophenol was found to be the most abundant methylnitrophenol, with concentrations ranging from the low pg m−3 range in rural areas to more than 200 pg m−3 in some samples from a suburban location.

  4. Stable carbon and oxygen isotope ratios of malachite from the patinas of ancient bronze objects

    International Nuclear Information System (INIS)

    Smith, A.W.

    1978-01-01

    13 C/ 12 C and 18 O/ 16 O ratios have been measured for 62 samples of the mineral malachite, taken from the patinas of ancient bronze objects (from Britain, Italy, Libya and China), in order to investigate any possible relationship which may exist between the isotope ratios and the burial conditions of the objects. The results indicate that the isotope ratios are controlled by complex factors related to the climate, vegetation and soil type at the burial site. It is suggested that the technique might be used, given favourable circumstances, in the characterization of patinas and as a possible aid in the detection of synthetic patination. (author)

  5. Geospatial modeling of plant stable isotope ratios - the development of isoscapes

    Science.gov (United States)

    West, J. B.; Ehleringer, J. R.; Hurley, J. M.; Cerling, T. E.

    2007-12-01

    Large-scale spatial variation in stable isotope ratios can yield critical insights into the spatio-temporal dynamics of biogeochemical cycles, animal movements, and shifts in climate, as well as anthropogenic activities such as commerce, resource utilization, and forensic investigation. Interpreting these signals requires that we understand and model the variation. We report progress in our development of plant stable isotope ratio landscapes (isoscapes). Our approach utilizes a GIS, gridded datasets, a range of modeling approaches, and spatially distributed observations. We synthesize findings from four studies to illustrate the general utility of the approach, its ability to represent observed spatio-temporal variability in plant stable isotope ratios, and also outline some specific areas of uncertainty. We also address two basic, but critical questions central to our ability to model plant stable isotope ratios using this approach: 1. Do the continuous precipitation isotope ratio grids represent reasonable proxies for plant source water?, and 2. Do continuous climate grids (as is or modified) represent a reasonable proxy for the climate experienced by plants? Plant components modeled include leaf water, grape water (extracted from wine), bulk leaf material ( Cannabis sativa; marijuana), and seed oil ( Ricinus communis; castor bean). Our approaches to modeling the isotope ratios of these components varied from highly sophisticated process models to simple one-step fractionation models to regression approaches. The leaf water isosocapes were produced using steady-state models of enrichment and continuous grids of annual average precipitation isotope ratios and climate. These were compared to other modeling efforts, as well as a relatively sparse, but geographically distributed dataset from the literature. The latitudinal distributions and global averages compared favorably to other modeling efforts and the observational data compared well to model predictions

  6. Determination of stable isotope ratio of lead in airborne particulate matter by ICP-MS

    International Nuclear Information System (INIS)

    Mukai, Hitoshi; Ambe, Yoshinari

    1990-01-01

    ICP-MS was applied to the measurement of stable isotope ratios of lead, which are used as an indicator of the source of lead in airborne particulate matter. For the measurement of lead isotopes ratios, the influences of machine conditions, lead concentration and matrix elements to the precision and accuracy of the measurements were studied. At a scanning mode, dwell time of 40∼160 μs gave the best precision to the isotope ratio measurements; about 0.3 % of R.S.D. for 206 Pb/ 207 Pb and 206 Pb/ 208 Pb, 0.6 % for 206 Pb/ 204 Pb. Precision of the measurement was better at a high concentration of lead in sample solution. The observed value of 206 Pb/ 207 Pb ratio was not affected by the lead concentration, but in the cases of 206 Pb/ 204 Pb and 206 Pb/ 208 Pb, about 1 % of the value changed in the observed ratios with the lead concentration of 100∼500 μg/l. Six matrix elements (Na, K, Ca, Mg, Al, Fe) did not affect the observed isotope ratios up to 200 mg/l. The lead isotope ratios of reference materials {Urban Particulates (NIST) and Vehicle Exhausted Particulates (NIES)} were measured by using two kinds of sample; crude sample and lead-isolated sample from matrix elements by anodic deposition. Both cases gave the same isotope ratio values, therefore, lead isotope ratios in airborne particulate samples can be measured by ICP-MS without any separation of lead from matrix elements. (author)

  7. Reactivity of paraquat with sodium salicylate: Formation of stable complexes

    International Nuclear Information System (INIS)

    Dinis-Oliveira, Ricardo Jorge; Guedes de Pinho, Paula; Ferreira, Antonio Cesar Silva; Silva, Artur M.S.; Afonso, Carlos; Bastos, Maria de Lourdes; Remiao, Fernando; Duarte, Jose Alberto; Carvalho, Felix

    2008-01-01

    Sodium salicylate (NaSAL) has been shown to be a promising antidote for the treatment of paraquat (PQ) poisonings. The modulation of the pro-oxidant and pro-inflammatory pathways, as well as the anti-thrombogenic properties of NaSAL are probably essential features for the healing effects provided by this drug. Nevertheless, a possible direct chemical reactivity between PQ and NaSAL is also a putative pathway to be considered, this hypothesis being the ground of the present study. In accordance, it is shown, for the first time that PQ and NaSAL react immediately in aqueous medium and within 2-3 min in the solid state. Photographs and scanning electron photomicrographs indicated that a new chemical entity is formed when both compounds are mixed. This assumption was corroborated by the evaluation of the melting point, and through several analytical techniques, namely ultraviolet/visible spectroscopy, nuclear magnetic resonance spectroscopy, gas chromatography/mass spectrometry/mass spectrometry (GC/MS/MS), liquid chromatography/electrospray ionization/mass spectrometry/mass spectrometry (LC/ESI/MS/MS) and infrared spectroscopy, which revealed that stable charge-transfer complexes are formed when PQ is mixed with NaSAL. LC/ESI/MS/MS allowed obtaining the stoichiometry of the charge-transfer complexes. In order to increase resolution, single value decomposition, acting as a filter, showed that the charge-transfer complexes with m/z 483, 643 and 803 correspond to the pseudo-molecular ions, respectively 1:2, 1:3 and 1:4 (PQ:NaSAL). In conclusion, these results provided a new and important mechanism of action of NaSAL against the toxicity mediated by PQ

  8. Stable equilibria for bootstrap-current-driven low aspect ratio tokamaks

    International Nuclear Information System (INIS)

    Miller, R.L.; Lin-Liu, Y.R.; Turnbull, A.D.; Chan, V.S.; Pearlstein, L.D.; Sauter, O.; Villard, L.

    1997-01-01

    Low aspect ratio tokamaks (LATs) can potentially provide a high ratio of plasma pressure to magnetic pressure β and high plasma current I at a modest size. This opens up the possibility of a high-power density compact fusion power plant. For the concept to be economically feasible, bootstrap current must be a major component of the plasma current, which requires operating at high β p . A high value of the Troyon factor β N and strong shaping is required to allow simultaneous operation at a high-β and high bootstrap fraction. Ideal magnetohydrodynamic stability of a range of equilibria at aspect ratio 1.4 is systematically explored by varying the pressure profile and shape. The pressure and current profiles are constrained in such a way as to assure complete bootstrap current alignment. Both β N and β are defined in terms of the vacuum toroidal field. Equilibria with β N ≥8 and β∼35%endash 55% exist that are stable to n=∞ ballooning modes. The highest β case is shown to be stable to n=0,1,2,3 kink modes with a conducting wall. copyright 1997 American Institute of Physics

  9. The relationship between carbon stable isotope ratios of hatchling down and egg yolk in Black-headed Gulls

    NARCIS (Netherlands)

    Klaassen, M.R.J.; Baarspul, T.; Dekkers, T.; Van Tienen, P.

    2004-01-01

    We reconstructed the nutrient source for egg synthesis by sampling Black-headed Gull (Larus ridibundus) eggs for yolk, analyzing their carbon stable isotope ratio, and comparing that to hatchling down. Most of the variation in carbon stable isotope ratio was explained by differences between nests,

  10. Variations in the stable isotope ratios of specific aromatic and aliphatic hydrocarbons from coal conversion processes

    Energy Technology Data Exchange (ETDEWEB)

    McRae, C.; Snape, C.E.; Fallick, A.E. [University of Strathclyde, Glasgow (United Kingdom). Dept. of Pure and Applied Chemistry

    1998-07-01

    To establish the scope for applying gas chromatography-isotope ratio mass spectrometry ({sup {delta}-13}C GC-IRMS) to molecular recognition problems in coal utilisation, {sup 13}C/{sup 12}C isotope ratios were determined for n-alkanes and polycyclic aromatic hydrocarbons (PAHs) as a function of coal rank and process conditions. Six coals ranging from a lignite to a low volatile bituminous coal were subjected to chloroform extraction, fixed-bed pyrolysis under hydrogen pressure (hydropyrolysis) and fluidised-bed (flash) pyrolysis. No significant variations in the stable isotope ratios of n-alkanes were evident as a function of either rank or conversion regime. In contrast, the isotope ratios of PAHs show large variations with those for hydropyrolysis (-23 to -25 parts per thousand) being similar to the bulk values of the initial coals and being isotopically heavier (less negative) than their fluidised-bed pyrolysis counterparts by 2-3 parts per thousand. However, the PAHs from fluidised-bed pyrolysis, which resemble closely those obtained from high temperature coal carbonization, are still heavier (by 2-3 parts per thousand) than those from diesel particulates and coal gasification and combustion residues. This provides a firm basis for the source apportionment of airborne PAHs in the proximity of coking plants, particularly with no major variations in the PAH isotope ratios being found as a function of rank.

  11. Stable oxygen and hydrogen isotopes of brines - comparing isotope ratio mass spectrometry and isotope ratio infrared spectroscopy

    Science.gov (United States)

    Ahrens, Christian; Koeniger, Paul; van Geldern, Robert; Stadler, Susanne

    2013-04-01

    Today's standard analytical methods for high precision stable isotope analysis of fluids are gas-water equilibration and high temperature pyrolysis coupled to isotope ratio mass spectrometers (IRMS). In recent years, relatively new laser-based analytical instruments entered the market that are said to allow high isotope precision data on nearly every media. This optical technique is referred to as isotope ratio infrared spectroscopy (IRIS). The objective of this study is to evaluate the capability of this new instrument type for highly saline solutions and a comparison of the analytical results with traditional IRMS analysis. It has been shown for the equilibration method that the presence of salts influences the measured isotope values depending on the salt concentration (see Lécuyer et al, 2009; Martineau, 2012). This so-called 'isotope salt effect' depends on the salt type and salt concentration. These factors change the activity in the fluid and therefore shift the isotope ratios measured by the equilibration method. Consequently, correction factors have to be applied to these analytical data. Direct conversion techniques like pyrolysis or the new laser instruments allow the measurement of the water molecule from the sample directly and should therefore not suffer from the salt effect, i.e. no corrections of raw values are necessary. However, due to high salt concentrations this might cause technical problems with the analytical hardware and may require labor-intensive sample preparation (e.g. vacuum distillation). This study evaluates the salt isotope effect for the IRMS equilibration technique (Thermo Gasbench II coupled to Delta Plus XP) and the laser-based IRIS instruments with liquid injection (Picarro L2120-i). Synthetic salt solutions (NaCl, KCl, CaCl2, MgCl2, MgSO4, CaSO4) and natural brines collected from the Stassfurt Salt Anticline (Germany; Stadler et al., 2012) were analysed with both techniques. Salt concentrations ranged from seawater salinity

  12. Phase behavior and structure of stable complexes between a long polyanion and a branched polycation

    Science.gov (United States)

    Mengarelli, Valentina; Zeghal, Mehdi; Auvray, Loïc; Clemens, Daniel

    2011-08-01

    The association between oppositely charged branched polyethylenimine (BPEI) and polymethacrylic acid (PMA) in the dilute regime is investigated using turbidimetric titration and electrophoretic mobility measurements. The complexation is controlled by tuning continuously the pH-sensitive charge of the polyacid in acidic solution. The formation of soluble and stable positively charged complexes is a cooperative process characterized by the existence of two regimes of weak and strong complexation. In the regime of weak complexation, a long PMA chain overcharged by several BPEI molecules forms a binary complex. As the charge of the polyacid increases, these binary complexes condense at a well defined charge ratio of the mixture to form large positively charged aggregates. The overcharging and the existence of two regimes of complexation are analyzed in the light of recent theories. The structure of the polyelectrolytes is investigated at higher polymer concentration by small angle neutron scattering. Binary complexes of finite size present an open structure where the polyacid chains connecting a small number of BPEI molecules have shrunk slightly. In the condensed complexes, BPEI molecules, wrapped by polyacid chains, form networks of stretched necklaces.

  13. Determination of the Geographical Origin of All Commercial Hake Species by Stable Isotope Ratio (SIR) Analysis.

    Science.gov (United States)

    Carrera, Mónica; Gallardo, José M

    2017-02-08

    The determination of the geographical origin of food products is relevant to comply with the legal regulations of traceability, to avoid food fraud, and to guarantee food quality and safety to the consumers. For these reasons, stable isotope ratio (SIR) analysis using an isotope ratio mass spectrometry (IRMS) instrument is one of the most useful techniques for evaluating food traceability and authenticity. The present study was aimed to determine, for the first time, the geographical origin for all commercial fish species belonging to the Merlucciidae family using SIR analysis of carbon (δ 13 C) and nitrogen (δ 15 N). The specific results enabled their clear classification according to the FAO (Food and Agriculture Organization of the United Nations) fishing areas, latitude, and geographical origin in the following six different clusters: European, North African, South African, North American, South American, and Australian hake species.

  14. Stable Carbon Isotope Ratio (δ13C Measurement of Graphite Using EA-IRMS System

    Directory of Open Access Journals (Sweden)

    Andrius Garbaras

    2015-06-01

    Full Text Available δ13C values in non-irradiated natural graphite were measured. The measurements were carried out using an elemental analyzer combined with stable isotope ratio mass spectrometer (EA-IRMS. The samples were prepared with ground and non-ground graphite, the part of which was mixed with Mg (ClO42. The best combustion of graphite in the oxidation furnace of the elemental analyzer was achieved when the amount of pulverized graphite ranged from 200 to 490 µg and the mass ratio C:Mg(ClO42 was approximately 1:10. The method for the graphite burning avoiding the isotope fractionation is proposed.DOI: http://dx.doi.org/10.5755/j01.ms.21.2.6873

  15. Measurement of stable isotope ratio of organic carbon in water samples

    International Nuclear Information System (INIS)

    Fujii, Toshihiro; Otsuki, Akira

    1977-01-01

    A new method for the measurement of stable isotope ratios was investigated and applied to organic carbon's isotope ratio measurements in water samples. A few river water samples from Tsuchiura city were tested. After the wet oxidation of organic carbons to carbon dioxide in a sealed ampoule, the isotope ratios were determined with the gas chromatograph-quadrupole mass spectrometer combined with a total organic carbon analyser, under the dynamic conditions. The GC-MS had been equipped with the multiple ion detector-digital integrator system. The ion intensities at m/e 44 and 45 were simultaneously measured at a switching rate of 1 ms. The measurements with carbon dioxide acquired from sodium carbonate (53 μg) gave the isotope ratios with the variation coefficient of 0.62%. However, the variation coefficients obtained from organic carbons in natural water samples were 2 to 3 times as high as that from sodium carbonate. This method is simple and rapid and may be applied to various fields especially in biology and medicine. (auth.)

  16. Dietary heterogeneity among Western industrialized countries reflected in the stable isotope ratios of human hair.

    Science.gov (United States)

    Valenzuela, Luciano O; Chesson, Lesley A; Bowen, Gabriel J; Cerling, Thure E; Ehleringer, James R

    2012-01-01

    Although the globalization of food production is often assumed to result in a homogenization of consumption patterns with a convergence towards a Western style diet, the resources used to make global food products may still be locally produced (glocalization). Stable isotope ratios of human hair can quantify the extent to which residents of industrialized nations have converged on a standardized diet or whether there is persistent heterogeneity and glocalization among countries as a result of different dietary patterns and the use of local food products. Here we report isotopic differences among carbon, nitrogen and sulfur isotope ratios of human hair collected in thirteen Western European countries and in the USA. European hair samples had significantly lower δ(13)C values (-22.7 to -18.3‰), and significantly higher δ(15)N (7.8 to 10.3‰) and δ(34)S (4.8 to 8.3‰) values than samples from the USA (δ(13)C: -21.9 to -15.0‰, δ(15)N: 6.7 to 9.9‰, δ(34)S: -1.2 to 9.9‰). Within Europe, we detected differences in hair δ(13)C and δ(34)S values among countries and covariation of isotope ratios with latitude and longitude. This geographic structuring of isotopic data suggests heterogeneity in the food resources used by citizens of industrialized nations and supports the presence of different dietary patterns within Western Europe despite globalization trends. Here we showed the potential of stable isotope analysis as a population-wide tool for dietary screening, particularly as a complement of dietary surveys, that can provide additional information on assimilated macronutrients and independent verification of data obtained by those self-reporting instruments.

  17. Dietary heterogeneity among Western industrialized countries reflected in the stable isotope ratios of human hair.

    Directory of Open Access Journals (Sweden)

    Luciano O Valenzuela

    Full Text Available Although the globalization of food production is often assumed to result in a homogenization of consumption patterns with a convergence towards a Western style diet, the resources used to make global food products may still be locally produced (glocalization. Stable isotope ratios of human hair can quantify the extent to which residents of industrialized nations have converged on a standardized diet or whether there is persistent heterogeneity and glocalization among countries as a result of different dietary patterns and the use of local food products. Here we report isotopic differences among carbon, nitrogen and sulfur isotope ratios of human hair collected in thirteen Western European countries and in the USA. European hair samples had significantly lower δ(13C values (-22.7 to -18.3‰, and significantly higher δ(15N (7.8 to 10.3‰ and δ(34S (4.8 to 8.3‰ values than samples from the USA (δ(13C: -21.9 to -15.0‰, δ(15N: 6.7 to 9.9‰, δ(34S: -1.2 to 9.9‰. Within Europe, we detected differences in hair δ(13C and δ(34S values among countries and covariation of isotope ratios with latitude and longitude. This geographic structuring of isotopic data suggests heterogeneity in the food resources used by citizens of industrialized nations and supports the presence of different dietary patterns within Western Europe despite globalization trends. Here we showed the potential of stable isotope analysis as a population-wide tool for dietary screening, particularly as a complement of dietary surveys, that can provide additional information on assimilated macronutrients and independent verification of data obtained by those self-reporting instruments.

  18. Stable isotope ratios in freshwater mussel shells as high resolution recorders of riverine environmental variation

    Science.gov (United States)

    Kukolich, S.; Kendall, C.; Dettman, D. L.

    2017-12-01

    The geochemical record stored in growth increments of freshwater mussel shells reveals annual to sub-annual changes in environmental conditions during the lifetime of the organism. The carbon, nitrogen, and oxygen stable isotope composition of aragonite shells responds to changes in water chemistry, temperature, streamflow, turbidity, growth rate, size, age, and reproduction. The goals of this study are to determine how stable isotopes can be used to reconstruct the conditions in which the mussels lived and to illuminate any vital effects that might obscure the isotopic record of those conditions. Previous research has suggested that annual δ13C values decrease in older freshwater mussel shells due to lower growth rates and greater incorporation of dietary carbon into the shell with increasing age. However, a high-resolution, seasonal investigation of δ13C, δ15N, and δ18O as they relate to organism age has not yet been attempted in freshwater mussels. A total of 28 Unionid mussels of three different species were collected live in 2011 in the Tennessee River near Paducah, Kentucky, USA. In this study, we analyzed the shell nacre and external organic layers for stable carbon, nitrogen, and oxygen isotope ratios, focusing on growth bands formed between 2006 and 2011. We present a time series of shell δ13C, δ18O, and δ15N values with monthly resolution. We also compare the shell-derived geochemical time series to a time series of the δ13C and δ15N of particulate organic matter, δ13C of DIC, δ18OWater, and water temperature in which the mussels lived. Results show that environmental factors such as water temperature and primary productivity dominate shell chemistry while animal age has little or no effect.

  19. A hypothesis-testing framework for studies investigating ontogenetic niche shifts using stable isotope ratios.

    Directory of Open Access Journals (Sweden)

    Caroline M Hammerschlag-Peyer

    Full Text Available Ontogenetic niche shifts occur across diverse taxonomic groups, and can have critical implications for population dynamics, community structure, and ecosystem function. In this study, we provide a hypothesis-testing framework combining univariate and multivariate analyses to examine ontogenetic niche shifts using stable isotope ratios. This framework is based on three distinct ontogenetic niche shift scenarios, i.e., (1 no niche shift, (2 niche expansion/reduction, and (3 discrete niche shift between size classes. We developed criteria for identifying each scenario, as based on three important resource use characteristics, i.e., niche width, niche position, and niche overlap. We provide an empirical example for each ontogenetic niche shift scenario, illustrating differences in resource use characteristics among different organisms. The present framework provides a foundation for future studies on ontogenetic niche shifts, and also can be applied to examine resource variability among other population sub-groupings (e.g., by sex or phenotype.

  20. Biomedical and Forensic Applications of Combined Catalytic Hydrogenation-Stable Isotope Ratio Analysis

    Directory of Open Access Journals (Sweden)

    Mark A. Sephton

    2007-01-01

    Full Text Available Studies of biological molecules such as fatty acids and the steroid hormones have the potential to benefit enormously from stable carbon isotope ratio measurements of individual molecules. In their natural form, however, the body’s molecules interact too readily with laboratory equipment designed to separate them for accurate measurements to be made.Some methods overcome this problem by adding carbon to the target molecule, but this can irreversibly overprint the carbon source ‘signal’. Hydropyrolysis is a newly-applied catalytic technique that delicately strips molecules of their functional groups but retains their carbon skeletons and stereochemistries intact, allowing precise determination of the carbon source. By solving analytical problems, the new technique is increasing the ability of scientists to pinpoint molecular indicators of disease, elucidate metabolic pathways and recognise administered substances in forensic investigations.

  1. Biomedical and Forensic Applications of Combined Catalytic Hydrogenation-Stable Isotope Ratio Analysis

    Science.gov (United States)

    Sephton, Mark A.; Meredith, Will; Sun, Cheng-Gong; Snape, Colin E.

    2007-01-01

    Studies of biological molecules such as fatty acids and the steroid hormones have the potential to benefit enormously from stable carbon isotope ratio measurements of individual molecules. In their natural form, however, the body’s molecules interact too readily with laboratory equipment designed to separate them for accurate measurements to be made. Some methods overcome this problem by adding carbon to the target molecule, but this can irreversibly overprint the carbon source ‘signal’. Hydropyrolysis is a newly-applied catalytic technique that delicately strips molecules of their functional groups but retains their carbon skeletons and stereochemistries intact, allowing precise determination of the carbon source. By solving analytical problems, the new technique is increasing the ability of scientists to pinpoint molecular indicators of disease, elucidate metabolic pathways and recognise administered substances in forensic investigations. PMID:19662175

  2. The stable carbon isotope ratios in benthic food webs of the gulf of Calvi, Corsica

    Science.gov (United States)

    Dauby, Patrick

    1989-02-01

    The Gulf of Calvi, Corsica, presents a wide diversity of biocoenoses, amongst which the seagrass Posidonia meadow is prevalent. More than 100 plant, animal and sediment samples from various biotopes were analysed for their stable carbon isotope ratios, to assess carbon flows within the food chains. Marine plants display a wide range of δ 13C values, from -6 to -32‰ but with three relatively well distinct peaks for Posidonia, brown algae and phytoplankton (-9, -19 and -23‰, respectively), which are the main carbon sources. The range of isotopic values of animals is narrower, from -14 to -24‰, suggesting that they feed mainly on algae and plankton. Computations based on simple equations show the proportion of each carbon source in the diet of the animals. Posidonia, notwithstanding their important biomass, appear to be a minor food source; this is possibly because of the transfer of their dead leaves, towards the shorelines, in winter.

  3. Caution on the use of liquid nitrogen traps in stable hydrogen isotope-ratio mass spectrometry

    Science.gov (United States)

    Coplen, Tyler B.; Qi, Haiping

    2010-01-01

    An anomalous stable hydrogen isotopic fractionation of 4 ‰ in gaseous hydrogen has been correlated with the process of adding liquid nitrogen (LN2) to top off the dewar of a stainless-steel water trap on a gaseous hydrogen-water platinum equilibration system. Although the cause of this isotopic fractionation is unknown, its effect can be mitigated by (1) increasing the capacity of any dewars so that they do not need to be filled during a daily analytic run, (2) interspersing isotopic reference waters among unknowns, and (3) applying a linear drift correction and linear normalization to isotopic results with a program such as Laboratory Information Management System (LIMS) for Light Stable Isotopes. With adoption of the above guidelines, measurement uncertainty can be substantially improved. For example, the long-term (months to years) δ2H reproducibility (1& sigma; standard deviation) of nine local isotopic reference waters analyzed daily improved substantially from about 1‰ to 0.58 ‰. This isotopically fractionating mechanism might affect other isotope-ratio mass spectrometers in which LN2 is used as a moisture trap for gaseous hydrogen

  4. Source Attribution of Cyanides using Anionic Impurity Profiling, Stable Isotope Ratios, Trace Elemental Analysis and Chemometrics

    Energy Technology Data Exchange (ETDEWEB)

    Mirjankar, Nikhil S.; Fraga, Carlos G.; Carman, April J.; Moran, James J.

    2016-01-08

    Chemical attribution signatures (CAS) for chemical threat agents (CTAs) are being investigated to provide an evidentiary link between CTAs and specific sources to support criminal investigations and prosecutions. In a previous study, anionic impurity profiles developed using high performance ion chromatography (HPIC) were demonstrated as CAS for matching samples from eight potassium cyanide (KCN) stocks to their reported countries of origin. Herein, a larger number of solid KCN stocks (n = 13) and, for the first time, solid sodium cyanide (NaCN) stocks (n = 15) were examined to determine what additional sourcing information can be obtained through anion, carbon stable isotope, and elemental analyses of cyanide stocks by HPIC, isotope ratio mass spectrometry (IRMS), and inductively coupled plasma optical emission spectroscopy (ICP-OES), respectively. The HPIC anion data was evaluated using the variable selection methods of Fisher-ratio (F-ratio), interval partial least squares (iPLS), and genetic algorithm-based partial least squares (GAPLS) and the classification methods of partial least squares discriminate analysis (PLSDA), K nearest neighbors (KNN), and support vector machines discriminate analysis (SVMDA). In summary, hierarchical cluster analysis (HCA) of anion impurity profiles from multiple cyanide stocks from six reported country of origins resulted in cyanide samples clustering into three groups: Czech Republic, Germany, and United States, independent of the associated alkali metal (K or Na). The three country groups were independently corroborated by HCA of cyanide elemental profiles and corresponded to countries with known solid cyanide factories. Both the anion and elemental CAS are believed to originate from the aqueous alkali hydroxides used in cyanide manufacture. Carbon stable isotope measurements resulted in two clusters: Germany and United States (the single Czech stock grouped with United States stocks). The carbon isotope CAS is believed to

  5. What climate information is recorded in stable isotope ratios of wood lignin methoxyl groups?

    Science.gov (United States)

    Greule, Markus; Keppler, Frank

    2010-05-01

    The stable isotope composition of the bioelements C, O, H and N in plant organic matter is known to be a very powerful for various environmental impacts. Particularly tree rings are suitable for this analysis because they exhibit a "climate archive" with a yearly or even biannual resolution. One of the most determined wood compounds is cellulose which amongst others is used to reconstruct the temperature due to measurement of stable hydrogen and oxygen isotopes. Therefore cellulose is converted into cellulose nitrate to eliminate the exchangeable hydroxyl hydrogen or equilibration methods are used. However, a general problem associated with the determination of the stable hydrogen values of marker compounds for the study of climate and environmental conditions is the isolation of the pure compound for analysis by isotope ratio mass spectrometry. Exploitation of components of wood as markers, in particular, has been restricted by the very labour intensive and time consuming preparation of samples (e.g. cellulose nitrate). An alternative way to record climate information from tree rings was recently proposed by Keppler et al. (2007) who measured the stable hydrogen values of methoxyl groups in wood. Lignin methoxyl groups are considered to be stable, i.e. the hydrogen atoms of the methoxyl moiety do not exchange with those of plant water during ongoing metabolic reactions in the plant. Thus the initial deuterium content of the methoxyl groups of lignin in woody tissue at formation is retained throughout the lifetime of the tree and in preserved tissue. The methoxyl content of lignin in wood is usually determined by the Zeisel method (Zeisel, 1885) - the reaction between methyl ethers and hydroiodic acid to form methyl iodide. Exploiting this reaction for the measurement of stable hydrogen values of lignin methoxyl groups ensures that during the entire analytical procedure the isotope signal is preserved since no isotopic exchange occurs between the methyl groups and

  6. Stable isotope methods: The effect of gut contents on isotopic ratios of zooplankton

    Science.gov (United States)

    Hill, J. M.; McQuaid, C. D.

    2011-05-01

    In the past decade there has been an increased awareness of the potential for methodological bias resulting from multiple pre-analytical procedures in foodweb interpretations based on stable isotope techniques. In the case of small organisms, this includes the effect of gut contents on whole body signatures. Although gut contents may not reflect actual assimilation, their carbon and nitrogen values will be isotopically lighter than after the same material has been assimilated. The potential skewing of isotopic ratios in whole organism samples is especially important for aquatic environments as many studies involve trophic relationships among small zooplankton. This is particularly important in pelagic waters, where herbivorous zooplankton comprise small taxa. Hence this study investigated the effect of gut contents on the δ13C and δ15N ratios of three size classes of zooplankton (1.0-2.0, 2.0-4.0 and >4.0 mm) collected using bongo net tows in the tropical waters of the south-west Indian Ocean. Animals were collected at night, when they were likely to be feeding, sieved into size classes and separated into genera. We focused on Euphausia spp which dominated zooplankton biomass. Three treatment types were processed: bulk animals, bulk animals without guts and tail muscle from each size class at 10 bongo stations. The δ15N ratios were influenced by zooplankton size class, presumably reflecting ontogenetic changes in diet. ANOVA post hoc results and correlations in δ15N signatures among treatments suggest that gut contents may not affect overall nitrogen signatures of Euphausia spp., but that δ13C signatures may be significantly altered by their presence. Carbon interpretations however, were complicated by potential effects of variation in chitin, lipids and metabolism among tissues and the possibility of opportunistic omnivory. Consequently we advocate gut evacuation before sacrifice in euphausiids if specific tissue dissection is impractical and recommend

  7. Seasonal changes in stable carbon isotope ratios within annual growth rings of Pinus radiata

    International Nuclear Information System (INIS)

    Walcroft, A.; Silvester, W.; Whitehead, D.; Kelliher, F.

    1997-01-01

    The stable isotope composition of photosynthetically assimilated carbon (δ 13 C) is determined by the ratio of the leaf internal CO 2 concentration (c i ) to that of the ambient air (c a ), and so reflects the contribution of both stomatal conductance (g s ) and the rate of photosynthesis (A). Assimilated carbon which is subsequently laid down as wood in annual growth rings may therefore represent a time integrated record of physiological responses by the whole tree to seasonal changes in the environmental variables regulating growth. We analysed the stable carbon isotope composition of Pinus radiata wood collected from two plantation forest sites in New Zealand which differ markedly in temperature, rainfall and soil characteristics. For both sites, discs were cut from the stem of several trees near ground level and whole wood samples were taken from within individual annual growth rings over a number of years. At one site, diameter bands were installed over the 1994 - 1996 growing seasons in order to date precisely the formation of wood during that time. Trees at each site consistently showed a seasonal pattern in the stable isotope composition of wood within individual growth rings. The amplitude of seasonal δ 13 C variation at the wet and dry sites were 1-2 per thousand and 4 per thousand respectively. Mean δ 13 C values from the wet site were 3 per thousand more 13 C depleted than those from the dry site implying lower water-use efficiency (carbon assimilation per unit transpiration). A process-based, model of stomatal conductance and CO 2 assimilation was combined with a soil-water balance model to estimate the average daily leaf-level intercellular CO 2 concentration (c i ). Over two growing seasons at each site there was generally good agreement between mean canopy-level c i derived from the tree-ring δ 13 C data and modelled leaf-level c i levels. Further, the ratio of annual CO 2 assimilation to transpiration estimated by the model for each site

  8. Stable isotope ratio analysis: A potential analytical tool for the authentication of South African lamb meat.

    Science.gov (United States)

    Erasmus, Sara Wilhelmina; Muller, Magdalena; van der Rijst, Marieta; Hoffman, Louwrens Christiaan

    2016-02-01

    Stable isotope ratios ((13)C/(12)C and (15)N/(14)N) of South African Dorper lambs from farms with different vegetation types were measured by isotope ratio mass spectrometry (IRMS), to evaluate it as a tool for the authentication of origin and feeding regime. Homogenised and defatted meat of the Longissimus lumborum (LL) muscle of lambs from seven different farms was assessed. The δ(13)C values were affected by the origin of the meat, mainly reflecting the diet. The Rûens and Free State farms had the lowest (p ⩽ 0.05) δ(15)N values, followed by the Northern Cape farms, with Hantam Karoo/Calvinia having the highest δ(15)N values. Discriminant analysis showed δ(13)C and δ(15)N differences as promising results for the use of IRMS as a reliable analytical tool for lamb meat authentication. The results suggest that diet, linked to origin, is an important factor to consider regarding region of origin classification for South African lamb. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Hydrogen and oxygen stable isotope ratios of milk in the United States.

    Science.gov (United States)

    Chesson, Lesley A; Valenzuela, Luciano O; O'Grady, Shannon P; Cerling, Thure E; Ehleringer, James R

    2010-02-24

    Models of hydrogen and oxygen incorporation in human tissues recognize the impact of geographic location on the isotopic composition of fluid intake, but inputs can include nonlocal beverages, such as milk. Milk and cow drinking water were collected from dairies, and commercially available milk was purchased from supermarkets and fast food restaurants. It was hypothesized that milk water delta(2)H and delta(18)O values record geographic location information. Correlations between milk water isotope ratios and purchase location tap water were significant. However, the amount of variation in milk delta(2)H and delta(18)O values explained by tap water was low, suggesting a single estimation of fluid input isotope ratios may not always be adequate in studies. The delta(2)H and delta(18)O values of paired milk and cow drinking water were related, suggesting potential for geographical origin assignment using stable isotope analysis. As an application example, milk water delta(18)O values were used to predict possible regions of origin for restaurant samples.

  10. Ranking stability and super-stable nodes in complex networks.

    Science.gov (United States)

    Ghoshal, Gourab; Barabási, Albert-László

    2011-07-19

    Pagerank, a network-based diffusion algorithm, has emerged as the leading method to rank web content, ecological species and even scientists. Despite its wide use, it remains unknown how the structure of the network on which it operates affects its performance. Here we show that for random networks the ranking provided by pagerank is sensitive to perturbations in the network topology, making it unreliable for incomplete or noisy systems. In contrast, in scale-free networks we predict analytically the emergence of super-stable nodes whose ranking is exceptionally stable to perturbations. We calculate the dependence of the number of super-stable nodes on network characteristics and demonstrate their presence in real networks, in agreement with the analytical predictions. These results not only deepen our understanding of the interplay between network topology and dynamical processes but also have implications in all areas where ranking has a role, from science to marketing.

  11. Relation between distribution coefficient of radioactive strontium and solid-liquid distribution ratio of background stable strontium

    International Nuclear Information System (INIS)

    Igarashi, Toshifumi; Mahara, Yasunori; Okamura, Masaki; Ashikawa, Nobuo.

    1992-01-01

    Distribution coefficients (K d ) of nuclides, which are defined as the ratio of the adsorbed concentration to the solution concentration, are important in predicting nuclide migration in the subsurface environment. This study was undertaken to contrust an effective method of determining the most pertinent K d value for simulating in situ distribution phenomena between the solid and liquid phases, by using background stable isotopes. This paper describes the applicability of this method to Sr by carrying out a batch Sr adsorption experiment where stable Sr coexisted with the radioactive isotope, 85 Sr, and by comparing the concentration distribution ratio of the background stable Sr with the K d value obtained by the batch experiment. The results showed that the K d of 85 Sr (K d85 ) agreed well with the K d of the coexisting stable Sr (K ds ) and that the two values decreased with an increase in the concentration of the stable Sr, when sand was used as an adsorbent. In addition, the K d85 corresponded to the ratio of the exchangeable solid-phase concentration of background stable Sr to the concentration of the background stable Sr in groundwater when the concentration of the coexisting stable Sr approached the background level. On the other hand, when powdered rock samples were used, the K d85 did not agree with the K ds , and the concentration distribution ratio of the background stable Sr was greater than the K d85 . This discrepancy might be due to the disequilibrium resulting from grinding the rock matrices. This suggests that measurement of the background stable Sr distribution ratio between the solid and liquid phases can be an effective method of estimating the K d of radioactive Sr when the groundwater is in satisfactory contact with the adsorption medium. (author)

  12. Expanding the isotopic toolbox: Applications of hydrogen and oxygen stable isotope ratios to food web studies

    Directory of Open Access Journals (Sweden)

    Hannah B Vander Zanden

    2016-03-01

    Full Text Available The measurement of stable carbon (δ13C and nitrogen (δ15N isotopes in tissues of organisms has formed the foundation of isotopic food web reconstructions, as these values directly reflect assimilated diet. In contrast, stable hydrogen (δ2H and oxygen (δ18O isotope measurements have typically been reserved for studies of migratory origin and paleoclimate reconstruction based on systematic relationships between organismal tissue and local environmental water. Recently, innovative applications using δ2H and, to a lesser extent, δ18O values have demonstrated potential for these elements to provide novel insights in modern food web studies. We explore the advantages and challenges associated with three applications of δ2H and δ18O values in food web studies. First, large δ2H differences between aquatic and terrestrial ecosystem end members can permit the quantification of energy inputs and nutrient fluxes between these two sources, with potential applications for determining allochthonous vs. autochthonous nutrient sources in freshwater systems and relative aquatic habitat utilization by terrestrial organisms. Next, some studies have identified a relationship between δ2H values and trophic position, which suggests that this marker may serve as a trophic indicator, in addition to the more commonly used δ15N values. Finally, coupled measurements of δ2H and δ18O values are increasing as a result of reduced analytical challenges to measure both simultaneously and may provide additional ecological information over single element measurements. In some organisms, the isotopic ratios of these two elements are tightly coupled, whereas the isotopic disequilibrium in other organisms may offer insight into the diet and physiology of individuals. Although a coherent framework for interpreting δ2H and δ18O data in the context of food web studies is emerging, many fundamental uncertainties remain. We highlight directions for targeted research that

  13. USE OF GC-MS/COMBUSTION/IRMS TO IDENTIFY AND DETERMINE THE STABLE CARBON ISOTOPIC RATIO OF INDIVIDUAL LIPIDS

    Science.gov (United States)

    A system that couples a gas chromatograph (GC) via a split to a quadrapole mass spectrometer (MS) and, through a combustion interface, to an isotope ratio mass spectrometer (IRMS) allows the simultaneous detection of electron impact mass spectra and stable carbon isotope ratio an...

  14. Using Lead Concentrations and Stable Lead Isotope Ratios to Identify Contamination Events in Alluvial Soils

    Directory of Open Access Journals (Sweden)

    Diane Saint-Laurent

    2010-01-01

    Full Text Available Soils contaminated with hydrocarbons (C10–C50, polycyclic aromatic hydrocarbons (PAHs, and other contaminants (e.g., As, Cd, Cu, Pb were recently discovered on the banks of the Saint-François and Massawippi rivers. Alluvial soils are contaminated over a distance of 100 kilometers, and the level of the contaminated-hydrocarbon layer in the soil profiles is among the highest at the Windsor and Richmond sites. Concentrations of lead and stable lead isotope ratios (204Pb/206Pb, 207Pb/206Pb, 208Pb/206Pb are also used to identify contamination events. The maximum and minimum values detected in soil profiles for arsenic, cadmium, and lead vary from 3.01 to 37.88 mg kg-1 (As, 0.11 to 0.81 mg kg-1 (Cd 12.32 to 149.13 mg kg-1 (Pb, respectively, while the 207Pb/206Pb isotopic ratio values are between 0.8545 and 0.8724 for all the profiles. The highest values of trace elements (As, Pb and Zn were detected in the hydrocarbon layer (C10–C50, most often located at the bottom of the profiles (160, 200, and 220 cm in depth. The various peaks recorded in the soils and the position of the profiles suggest that various contaminants were transported by the river on several occasions and infiltrated the soil matrix or deposited on floodplains during successive floods. Atmospheric particles which entered the river or deposited on riverbanks must also be considered as another source of pollution recorded in soils.

  15. Stable isotope ratios indicate diet and habitat use in New World monkeys.

    Science.gov (United States)

    Schoeninger, M J; Iwaniec, U T; Glander, K E

    1997-05-01

    This paper demonstrates the use of stable isotope ratios of carbon and nitrogen in animal tissue for indicating aspects of species behavioral strategy. We analyzed hair from individuals representing four species of New World monkeys (Alouatta palliata, the mantled howler; Ateles geoffroyi, the spider monkey; Cebus capucinus, the capuchin; and Brachyteles arachnoides, the woolly-spider monkey or muriqui) for delta 13C and delta 15N using previously developed methods. There are no significant differences in either carbon or nitrogen ratios between sexes, sampling year, or year of analysis. Seasonal differences in delta 13C reached a low level of significance but do not affect general patterns. Variation within species was similar to that recorded previously within single individuals. The omega 13C data show a bimodal distribution with significant difference between the means. The two monkey populations living in an evergreen forest were similar to each other and different from the other two monkey populations that inhabited dry, deciduous forests. This bimodal distribution is independent of any particular species' diet and reflects the level of leaf cover in the two types of forest. The delta 15N data display three significantly different modes. The omnivorous capuchins were most positive reflecting a trophic level offset. The spider monkeys and the muriquis were similar to one another and significantly more positive than the howlers. This distribution among totally herbivorous species correlates with the ingestion of legumes by the howler monkey population. In combination, these data indicate that museum-curated primate material can be analyzed to yield information on forest cover and diet in populations and species lacking behavioral data.

  16. Using Lead Concentrations and Stable Lead Isotope Ratios to Identify Contamination Events in Alluvial Soils

    International Nuclear Information System (INIS)

    Saint-Laurent, D.; St-Laurent, J.; Hahni, M.; Chapados, C.; Ghaleb, B.

    2010-01-01

    Soils contaminated with hydrocarbons (C10,C50), polycyclic aromatic hydrocarbons (PAHs), and other contaminants (e.g., As, Cd, Cu, Pb) were recently discovered on the banks of the Saint-Francois and Massawippi rivers. Alluvial soils are contaminated over a distance of 100 kilometers, and the level of the contaminated-hydrocarbon layer in the soil profiles is among the highest at the Windsor and Richmond sites. Concentrations of lead and stable lead isotope ratios ( 204 Pb/ 206 Pb, 206 Pb/ 207 Pb, 208 Pb/ 20 '6Pb) are also used to identify contamination events. The maximum and minimum values detected in soil profiles for arsenic, cadmium, and lead vary from 3.01 to 37.88?mg kg -1 (As), 0.11 to 0.81?mg kg-1 (Cd) 12.32 to 149.13?mg kg -1 (Pb), respectively, while the 207 Pb/ 206 Pb isotopic ratio values are between 0.8545 and 0.8724 for all the profiles. The highest values of trace elements (As, Pb and Zn) were detected in the hydrocarbon layer (C10,C50), most often located at the bottom of the profiles (160, 200, and 220 cm in depth). The various peaks recorded in the soils and the position of the profiles suggest that various contaminants were transported by the river on several occasions and infiltrated the soil matrix or deposited on flood plains during successive floods. Atmospheric particles which entered the river or deposited on riverbanks must also be considered as another source of pollution recorded in soils

  17. An Ocean Sediment Core-Top Calibration of Foraminiferal (Cibicides) Stable Carbon Isotope Ratios

    Science.gov (United States)

    Schmittner, A.; Mix, A. C.; Lisiecki, L. E.; Peterson, C.; Mackensen, A.; Cartapanis, O. A.

    2015-12-01

    Stable carbon isotope ratios (δ13C) measured on calcium carbonate shells of benthic foraminifera (cibicides) from late Holocene sediments (δ13CCib) are compiled and compared with newly updated datasets of contemporary water-column δ13C observations of dissolved inorganic carbon (δ13CDIC) as the initial core-top calibration of the international Ocean Circulation and CarbonCycling (OC3) project. Using selection criteria based on the spatial distance between samples we find high correlation between δ13CCib and natural (pre-industrial) δ13CDIC, confirming earlier work. However, our analysis reveals systematic differences such as higher (lower) δ13CCib values in the Atlantic (Indian and Pacific) oceans. Regression analyses are impacted by anthropogenic carbon and suggest significant carbonate ion, temperature, and pressure effects, consistent with lab experiments with planktonic foraminifera and theory. The estimated standard error of core-top sediment data is generally σ ~= 0.25 ‰, whereas modern foram data from the South Atlantic indicate larger errors (σ ~= 0.4 ‰).

  18. Meridional distribution and seasonal variation of stable oxygen isotope ratio of precipitation in the Southern Ocean

    Directory of Open Access Journals (Sweden)

    Kayo Nakamura

    2010-07-01

    Full Text Available The stable oxygen isotope ratio(δ^O in precipitation is known to have important meridional and seasonal variations, but there are almost no measurements of δ^O in precipitation over polar oceans. The present research took advantage of 4 opportunities for in situ observations in summer and winter at high latitudes in the Southern Ocean. In addition, we analyzed samples of precipitation at Syowa Station in 2008 to obtain year-round data. Based on these data, we consider the meridional and seasonal variations of δ^O in precipitation over the Southern Ocean. In general, δ^O decreases with increasing latitude, and is lower in winter than in summer. The latitude gradient is stronger in winter. At 60°S, δ^O is -5.4‰ and -11.3‰ in summer and winter, respectively, while the corresponding figures at 66°S are -10.5‰ and -20.8‰. These results will help us understand the mechanisms of the salinity distribution and its variation in the Antarctic Ocean.

  19. Mathematical Models to Determine Stable Behavior of Complex Systems

    Science.gov (United States)

    Sumin, V. I.; Dushkin, A. V.; Smolentseva, T. E.

    2018-05-01

    The paper analyzes a possibility to predict functioning of a complex dynamic system with a significant amount of circulating information and a large number of random factors impacting its functioning. Functioning of the complex dynamic system is described as a chaotic state, self-organized criticality and bifurcation. This problem may be resolved by modeling such systems as dynamic ones, without applying stochastic models and taking into account strange attractors.

  20. Complex cobordism and stable homotopy groups of spheres

    CERN Document Server

    Ravenel, Douglas C

    2003-01-01

    Since the publication of its first edition, this book has served as one of the few available on the classical Adams spectral sequence, and is the best account on the Adams-Novikov spectral sequence. This new edition has been updated in many places, especially the final chapter, which has been completely rewritten with an eye toward future research in the field. It remains the definitive reference on the stable homotopy groups of spheres. The first three chapters introduce the homotopy groups of spheres and take the reader from the classical results in the field though the computational aspects

  1. Disentangling effects of growth and nutritional status on seabird stable isotope ratios

    Science.gov (United States)

    Sears, J.; Hatch, Shyla A.; O'Brien, D. M.

    2009-01-01

    A growing number of studies suggest that an individual's physiology affects its carbon and nitrogen stable isotope signatures, obscuring a signal often assumed to be only a reflection of diet and foraging location. We examined effects of growth and moderate food restriction on red blood cell (RBC) and feather ??15N and ??13C in rhinoceros auklet chicks (Cerorhinca monocerata), a piscivorous seabird. Chicks were reared in captivity and fed either control (75 g/day; n = 7) or ~40% restricted (40 g/day; n = 6) amounts of high quality forage fish. We quantified effects of growth on isotopic fractionation by comparing ??15N and ??13C in control chicks to those of captive, non-growing subadult auklets (n = 11) fed the same diet. To estimate natural levels of isotopic variation, we also collected blood from a random sample of free-living rhinoceros auklet adults and chicks in the Gulf of Alaska (n = 15 for each), as well as adult feather samples (n = 13). In the captive experiment, moderate food restriction caused significant depletion in ??15N of both RBCs and feathers in treatment chicks compared to control chicks. Growth also induced depletion in RBC ??15N, with chicks exhibiting lower ??15N when they were growing the fastest. As growth slowed, ??15N increased, resulting in an overall pattern of enrichment over the course of the nestling period. Combined effects of growth and restriction depleted ??15N in chick RBCs by 0.92???. We propose that increased nitrogen-use efficiency is responsible for 15N depletion in both growing and food-restricted chicks. ??15N values in RBCs of free-ranging auklets fell within a range of only 1.03???, while feather ??15N varied widely. Together, our captive and field results suggest that both growth and moderate food restriction can affect stable isotope ratios in an ecologically meaningful way in RBCs although not feathers due to greater natural variability in this tissue. ?? 2008 Springer-Verlag.

  2. Assessing connectivity of estuarine fishes based on stable isotope ratio analysis

    Science.gov (United States)

    Herzka, Sharon Z.

    2005-07-01

    Assessing connectivity is fundamental to understanding the population dynamics of fishes. I propose that isotopic analyses can greatly contribute to studies of connectivity in estuarine fishes due to the high diversity of isotopic signatures found among estuarine habitats and the fact that variations in isotopic composition at the base of a food web are reflected in the tissues of consumers. Isotopic analysis can be used for identifying nursery habitats and estimating their contribution to adult populations. If movement to a new habitat is accompanied by a shift to foods of distinct isotopic composition, recent immigrants and residents can be distinguished based on their isotopic ratios. Movement patterns thus can be reconstructed based on information obtained from individuals. A key consideration is the rate of isotopic turnover, which determines the length of time that an immigrant to a given habitat will be distinguishable from a longtime resident. A literature survey indicated that few studies have measured turnover rates in fishes and that these have focused on larvae and juveniles. These studies reveal that biomass gain is the primary process driving turnover rates, while metabolic turnover is either minimal or undetectable. Using a simple dilution model and biomass-specific growth rates, I estimated that young fishes with fast growth rates will reflect the isotopic composition of a new diet within days or weeks. Older or slower-growing individuals may take years or never fully equilibrate. Future studies should evaluate the factors that influence turnover rates in fishes during various stages of the life cycle and in different tissues, as well as explore the potential for combining stable isotope and otolith microstructure analyses to examine the relationship between demographic parameters, movement and connectivity.

  3. Emerging techniques in vegetable oil analysis using stable isotope ratio mass spectrometry

    Directory of Open Access Journals (Sweden)

    Rhodes, Christopher

    2002-03-01

    Full Text Available As the practice of vegetable oil adulteration becomes more sophisticated, the possibility to subvert detection using established techniques such as capillary gas chromatography is increasing. One of the most powerful techniques to be used in food authenticity studies is stable isotope ratio mass spectrometry (SIRMS which utilises differences in the natural abundance of the stable isotopes of the ‘light’ bio-elements hydrogen, nitrogen, carbon, oxygen and sulfur to detect food fraud. SIRMS has found application in the authentication of a wide range of foodstuffs, including fruit juices, wines, spirits, honey and to detect the adulteration of flavour compounds with synthetic analogues. This papers reviews the current state-of-the-art for the authentication of vegetable oils using SIRMS and highlights emergent techniques such as compound- and position specific-isotope mass spectrometry. These latter developments offer the potential to provide more rapid and improved detection of the economic adulteration of vegetable oils.A medida que la práctica de la adulteración de aceites vegetales se hace más sofisticada, las posibilidades de evitar la detección utilizando técnicas tradicionales como la cromatografía de gases en columna capilar aumentan. Una de las técnicas más poderosas que más se utilizan en los estudios de autentificación de alimentos es la espectrometría de masas de relaciones isotópicas, que utiliza diferencias en la abundancia natural de isótopos estables de elementos ligeros biológicos hidrógeno, nitrógeno, carbón, oxigeno y azufre para detectar fraude en los alimentos. La espectrometría de masas de relaciones isotópicas ha encontrado aplicación en la autentificación de una amplia gama de alimentos, incluyendo zumos de frutas, vinos, bebidas alcohólicas de alta graduación, miel, y en la detección de la adulteración de los compuestos aromáticos con sus análogos de origen sintético. Este trabajo

  4. Detecting animal by-product intake using stable isotope ratio mass spectrometry (IRMS).

    Science.gov (United States)

    da Silva, D A F; Biscola, N P; Dos Santos, L D; Sartori, M M P; Denadai, J C; da Silva, E T; Ducatti, C; Bicudo, S D; Barraviera, B; Ferreira, R S

    2016-11-01

    Sheep are used in many countries as food and for manufacturing bioproducts. However, when these animals consume animal by-products (ABP), which is widely prohibited, there is a risk of transmitting scrapie - a fatal prion disease in human beings. Therefore, it is essential to develop sensitive methods to detect previous ABP intake to select safe animals for producing biopharmaceuticals. We used stable isotope ratio mass spectrometry (IRMS) for 13 C and 15 N to trace animal proteins in the serum of three groups of sheep: 1 - received only vegetable protein (VP) for 89 days; 2 - received animal and vegetable protein (AVP); and 3 - received animal and vegetable protein with animal protein subsequently removed (AVPR). Groups 2 and 3 received diets with 30% bovine meat and bone meal (MBM) added to a vegetable diet (from days 16-89 in the AVP group and until day 49 in the AVPR group, when MBM was removed). The AVPR group showed 15 N equilibrium 5 days after MBM removal (54th day). Conversely, 15 N equilibrium in the AVP group occurred 22 days later (76th day). The half-life differed between these groups by 3.55 days. In the AVPR group, 15 N elimination required 53 days, which was similar to this isotope's incorporation time. Turnover was determined based on natural 15 N signatures. IRMS followed by turnover calculations was used to evaluate the time period for the incorporation and elimination of animal protein in sheep serum. The δ 13 C and δ 15 N values were used to track animal protein in the diet. This method is biologically and economically relevant for the veterinary field because it can track protein over time or make a point assessment of animal feed with high sensitivity and resolution, providing a low-cost analysis coupled with fast detection. Isotopic profiles could be measured throughout the experimental period, demonstrating the potential to use the method for traceability and certification assessments. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Stable assembly of HIV-1 export complexes occurs cotranscriptionally

    DEFF Research Database (Denmark)

    Nawroth, Isabel; Mueller, Florian; Basyuk, Eugenia

    2014-01-01

    The HIV-1 Rev protein mediates export of unspliced and singly spliced viral transcripts by binding to the Rev response element (RRE) and recruiting the cellular export factor CRM1. Here, we investigated the recruitment of Rev to the transcription sites of HIV-1 reporters that splice either post......- or cotranscriptionally. In both cases, we observed that Rev localized to the transcription sites of the reporters and recruited CRM1. Rev and CRM1 remained at the reporter transcription sites when cells were treated with the splicing inhibitor Spliceostatin A (SSA), showing that the proteins associate with RNA prior...... to or during early spliceosome assembly. Fluorescence recovery after photobleaching (FRAP) revealed that Rev and CRM1 have similar kinetics as the HIV-1 RNA, indicating that Rev, CRM1, and RRE-containing RNAs are released from the site of transcription in one single export complex. These results suggest...

  6. Assessment of Stable Isotope Distribution in Complex Systems

    Science.gov (United States)

    He, Y.; Cao, X.; Wang, J.; Bao, H.

    2017-12-01

    Biomolecules in living organisms have the potential to approach chemical steady state and even apparent isotope equilibrium because enzymatic reactions are intrinsically reversible. If an apparent local equilibrium can be identified, enzymatic reversibility and its controlling factors may be quantified, which helps to understand complex biochemical processes. Earlier research on isotope fractionation tends to focus on specific process and compare mostly two different chemical species. Using linear regression, "Thermodynamic order", which refers to correlated δ13C and 13β values, has been proposed to be present among many biomolecules by Galimov et al. However, the concept "thermodynamic order" they proposed and the approach they used has been questioned. Here, we propose that the deviation of a complex system from its equilibrium state can be rigorously described as a graph problem as is applied in discrete mathematics. The deviation of isotope distribution from equilibrium state and apparent local isotope equilibrium among a subset of biomolecules can be assessed using an apparent fractionation difference matrix (|Δα|). Applying the |Δα| matrix analysis to earlier published data of amino acids, we show the existence of apparent local equilibrium among different amino acids in potato and a kind of green alga. The existence of apparent local equilibrium is in turn consistent with the notion that enzymatic reactions can be reversible even in living systems. The result also implies that previous emphasis on external carbon source intake may be misplaced when studying isotope distribution in physiology. In addition to the identification of local equilibrium among biomolecules, the difference matrix approach has the potential to explore chemical or isotope equilibrium state in extraterrestrial bodies, to distinguish living from non-living systems, and to classify living species. This approach will benefit from large numbers of systematic data and advanced pattern

  7. Expanding the isotopic toolbox: Applications of hydrogen and oxygen stable isotope ratios to food web studies

    OpenAIRE

    Hannah B Vander Zanden; David X Soto; Gabriel J Bowen; Keith A Hobson; Keith A Hobson

    2016-01-01

    The measurement of stable carbon (δ13C) and nitrogen (δ15N) isotopes in tissues of organisms has formed the foundation of isotopic food web reconstructions, as these values directly reflect assimilated diet. In contrast, stable hydrogen (δ2H) and oxygen (δ18O) isotope measurements have typically been reserved for studies of migratory origin and paleoclimate reconstruction based on systematic relationships between organismal tissue and local environmental water. Recently, innovative applicat...

  8. Expanding the Isotopic Toolbox: Applications of Hydrogen and Oxygen Stable Isotope Ratios to Food Web Studies

    OpenAIRE

    Vander Zanden, Hannah B.; Soto, David X.; Bowen, Gabriel J.; Hobson, Keith A.

    2016-01-01

    The measurement of stable carbon (δ13C) and nitrogen (δ15N) isotopes in tissues of organisms has formed the foundation of isotopic food web reconstructions, as these values directly reflect assimilated diet. In contrast, stable hydrogen (δ2H) and oxygen (δ18O) isotope measurements have typically been reserved for studies of migratory origin and paleoclimate reconstruction based on systematic relationships between organismal tissue and local environmental water. Recently, innovative applicatio...

  9. Comparison of stable carbon isotope ratios in the whole wood, cellulose and lignin of Oak tree-rings

    CSIR Research Space (South Africa)

    Loader, NJ

    2003-08-01

    Full Text Available The stable carbon isotope ratios (N13C) of whole wood, cellulose and acid-insoluble lignin from annual latewood increments of Quereus robur L., from modern and sub-fossil wood, were measured and their potential use as palaeo environmental indicators...

  10. Investigation of groundwater-streamflow interactions in the Bega alluvial aquifer using tritium and stable isotope ratios

    International Nuclear Information System (INIS)

    Stone, D.J.M.; Thomas, M.; Russell, G.

    2001-01-01

    An isotope hydrology study of the Bega Valley groundwater system has been made. The investigation which focussed on environmental tritium and stable isotope ratios confirms that that the groundwater in the alluvial aquifer of the Bega Valley is sustainable at the current usage rate

  11. Characterization of sources of lead in the urban air of Asia using ratios of stable lead isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Mukai, H.; Furuta, N.; Fujii, T.; Ambe, Y.; Sakamoto, K.; Hashimoto, Y. (National Institute of Environmental Studies, Tsukuba (Japan). Environmental Chemistry Division)

    1993-07-01

    Airborne particulate matter was collected at urban sites in six Asian countries (Japan, South Korea, China, Thailand, Sri Lanka, and Indonesia), and the stable lead isotope ratios were measured. Some source-related materials, such as coal and leaded gasoline, were also analyzed and compared to the ratios observed in airborne lead. Airborne lead isotope ratios differed considerably from each other, and these differences corresponded to differences in the regional source of lead. Leaded gasoline was still the primary source of lead in some cities in Asia, and the lead isotope ratios were strongly influenced by those of leaded gasoline. In Chinese and Korean cities, however, the considerable effect from coal combustion and industrial activity was also observed in their isotope ratios, despite leaded gasoline use. On the other hand, only refuse incineration was a possible single source of lead in Japanese air from the view of lead isotope ratios. 49 refs., 13 figs., 3 tabs.

  12. Amphiboles as indicators of mantle source contamination: Combined evaluation of stable H and O isotope compositions and trace element ratios

    NARCIS (Netherlands)

    Demény, A.; Harangi, S.; Vennemann, T.W.; Casillas, R.; Horváth, P.; Milton, A.J.; Mason, P.R.D.; Ulianov, A.

    2012-01-01

    Stable isotope and trace element compositions of igneous amphiboles from different tectonic settings (ocean island basalts, intraplate alkaline basalts, subduction-related andesitic complexes) were compiled to help understand the role of fluids and melts in subduction-related mantle metasomatism

  13. Online stable carbon isotope ratio measurement in formic acid, acetic acid, methanol and ethanol in water by high performance liquid chromatography-isotope ratio mass spectrometry

    International Nuclear Information System (INIS)

    Tagami, Keiko; Uchida, Shigeo

    2008-01-01

    A suitable analysis condition was determined for high performance liquid chromatography-isotope ratio mass spectrometry (HPLC-IRMS) while making sequential measurements of stable carbon isotope ratios of δ 13 C in formic acid, acetic acid, methanol and ethanol dissolved in water. For this online column separation method, organic reagents are not applicable due to carbon contamination; thus, water and KH 2 PO 4 at low concentrations were tested as mobile phase in combination with a HyPURITY AQUASTAR TM column. Formic acid, acetic acid, methanol and ethanol were separated when 2 mM KH 2 PO 4 aqueous solution was used. Under the determined analysis condition for HPLC-IRMS, carbon concentrations could be measured quantitatively as well as carbon isotope ratio when carbon concentration was higher than 0.4 mM L for each chemical

  14. Tracing lead pollution sources in abandoned mine areas using stable Pb isotope ratios.

    Science.gov (United States)

    Yoo, Eun-Jin; Lee, Jung-A; Park, Jae-Seon; Lee, Khanghyun; Lee, Won-Seok; Han, Jin-Seok; Choi, Jong-Woo

    2014-02-01

    This study focused on Pb isotope ratios of sediments in areas around an abandoned mine to determine if the ratios can be used as a source tracer. For pretreatment, sediment samples were dissolved with mixed acids, and a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS, Nu plasma II) was used to investigate the Pb isotopic composition of the samples. The measured isotope ratios were then corrected for instrumental mass fractionation by measuring the (203)Tl/(205)Tl ratio. Repeated measurements with the NIST SRM 981 reference material showed that the precision of all ratios was below 104 ppm (±2σ) for 50 ng/g. The isotope ratios ((207)Pb/(206)Pb) found were 0.85073 ± 0.0004~0.85373 ± 0.0003 for the main stream, while they were 0.83736 ± 0.0010 for the tributary and 0.84393 ± 0.0002 for the confluence. A binary mixing equation for isotope ratios showed that the contributions of mine lead to neighboring areas were up to 60%. Therefore, Pb isotope ratios can be a good source tracer for areas around abandoned mines.

  15. Postmortem study of stable carbon isotope ratios in human cerebellar DNA: preliminary results

    International Nuclear Information System (INIS)

    Slatkin, D.N.; Irsa, A.P.; Friedman, L.

    1978-01-01

    It is observed that 13 C/ 12 C ratios in tissue specimens removed postmortem in the United States and Canada are significantly different from corresponding ratios in European specimens. On the basis of this information, measurements of carbon isotope ratios in DNA isolated from cerebella of native-born and European-born North Americans are in progress with the goal of estimating the average lifetime rate of DNA turnover in human neurons. Preliminary results from twenty postmortem examinations are consistent with the hypothesis that a significant proportion of human cerebellar DNA is renewed during the lifetime of an individual

  16. New approaches for stable isotope ratio measurements. Proceedings of an advisory group meeting

    International Nuclear Information System (INIS)

    2001-10-01

    This report includes a summary of discussions at the meeting and contributions on isotope applications in a range of specific biogeochemical fields using the new analytical techniques. It is expected to serve as a useful reference for researchers and laboratory managers who plan to develop or apply state-of-the-art stable isotope techniques. Individual contributions contained in this book have been indexed separately

  17. New approaches for stable isotope ratio measurements. Proceedings of an advisory group meeting

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-10-01

    This report includes a summary of discussions at the meeting and contributions on isotope applications in a range of specific biogeochemical fields using the new analytical techniques. It is expected to serve as a useful reference for researchers and laboratory managers who plan to develop or apply state-of-the-art stable isotope techniques. Individual contributions contained in this book have been indexed separately.

  18. The complex dynamics of wishful thinking: the critical positivity ratio.

    Science.gov (United States)

    Brown, Nicholas J L; Sokal, Alan D; Friedman, Harris L

    2013-12-01

    We examine critically the claims made by Fredrickson and Losada (2005) concerning the construct known as the "positivity ratio." We find no theoretical or empirical justification for the use of differential equations drawn from fluid dynamics, a subfield of physics, to describe changes in human emotions over time; furthermore, we demonstrate that the purported application of these equations contains numerous fundamental conceptual and mathematical errors. The lack of relevance of these equations and their incorrect application lead us to conclude that Fredrickson and Losada's claim to have demonstrated the existence of a critical minimum positivity ratio of 2.9013 is entirely unfounded. More generally, we urge future researchers to exercise caution in the use of advanced mathematical tools, such as nonlinear dynamics, and in particular to verify that the elementary conditions for their valid application have been met. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  19. Seasonal Variations in Stable Isotope Ratios of Oxygen and Hydrogen in Two Tundra Rivers in NE European Russia

    Energy Technology Data Exchange (ETDEWEB)

    Huitu, E.; Arvola, L. [Lammi Biological Station, University of Helsinki (Finland); Sonninen, E. [Radiocarbon Dating Laboratory, University of Helsinki (Finland)

    2013-07-15

    The variability in stable isotope ratios of oxygen and hydrogen ({delta} {sup 18}O and {delta}{sup 2}H values) in river waters in northeast European Russia was studied for the period from July 2007 to october 2008. Exceptional isotope composition in precipitation obtained during the sampling period was clearly traced in the composition of river waters. Water from permafrost thawing did not make a great contribution to river flow. (author)

  20. Nonsphericity Index and Size Ratio Identify Morphologic Differences between Growing and Stable Aneurysms in a Longitudinal Study of 93 Cases.

    Science.gov (United States)

    Chien, A; Xu, M; Yokota, H; Scalzo, F; Morimoto, E; Salamon, N

    2018-01-25

    Recent studies have strongly associated intracranial aneurysm growth with increased risk of rupture. Identifying aneurysms that are likely to grow would be beneficial to plan more effective monitoring and intervention strategies. Our hypothesis is that for unruptured intracranial aneurysms of similar size, morphologic characteristics differ between aneurysms that continue to grow and those that do not. From aneurysms in our medical center with follow-up imaging dates in 2015, ninety-three intracranial aneurysms (23 growing, 70 stable) were selected. All CTA images for the aneurysm diagnosis and follow-up were collected, a total of 348 3D imaging studies. Aneurysm 3D geometry for each imaging study was reconstructed, and morphologic characteristics, including volume, surface area, nonsphericity index, aspect ratio, and size ratio were calculated. Morphologic characteristics were found to differ between growing and stable groups. For aneurysms of 7 mm, volume ( P differ between those that are growing and those that are stable. The nonsphericity index, in particular, was found to be higher among growing aneurysms. The size ratio was found to be the second most significant parameter associated with growth. © 2018 by American Journal of Neuroradiology.

  1. Is the principle of a stable heinrich ratio a myth? - A multimethod analysis

    NARCIS (Netherlands)

    Gallivan, Steve; Taxis, Katja; Franklin, Bryony Dean; Barber, Nick

    2008-01-01

    Background: Safety improvements are sometimes based on the premise that introducing measures to combat minor or no-harm incidents proportionately reduces the incidence of major incidents involving harm. This is in line with the principle of the Heinrich ratio, which asserts that there is a

  2. Stable carbon isotope ratio profiling of illicit testosterone preparations--domestic and international seizures.

    Science.gov (United States)

    Brooker, Lance; Cawley, Adam; Drury, Jason; Edey, Claire; Hasick, Nicole; Goebel, Catrin

    2014-10-01

    Gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) is now established as a robust and mature analytical technique for the doping control of endogenous anabolic androgenic steroids in human sport. It relies on the assumption that the carbon isotope ratios of naturally produced steroids are significantly different to synthetically manufactured testosterone or testosterone prohormones used in commercial medical or dietary supplement products. Recent publications in this journal have highlighted the existence of black market testosterone preparations with carbon isotope ratios within the range reported for endogenous steroids (i.e. δ(13) C ≥ -25.8 ‰). In this study, we set out to profile domestic and international law enforcement seizures of illicit testosterone products to monitor the prevalence of 'enriched' substrates--which if administered to human subjects would be considered problematic for the use of current GC-C-IRMS methodologies for the doping control of testosterone in sport. The distribution of δ(13) C values for this illicit testosterone sample population (n = 283) ranged from -23.4 ‰ to -32.9 ‰ with mean and median of -28.6 ‰--comparable to previous work. However, only 13 out of 283 testosterone samples (4.6 %) were found to display δ(13) C values ≥ -25.8 ‰, confirming that in the vast majority of cases of illicit testosterone administration, current GC-C-IRMS doping control procedures would be capable of confirming misuse. Copyright © 2014 John Wiley & Sons, Ltd.

  3. New manuscript guidelines for the reporting of stable hydrogen, carbon, and oxygen isotope-ratio data

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1995-10-01

    To eliminate possible confusion in the reporting of isotopic abundances on non-corresponding scales, the Commission on Atomic Weights and Isotopic Abundances recommended at the 37{sup th} General Assembly at Lisbon, Portugal that (i) {sup 2}H/{sup 1}H relative ratios of all substances be expressed relative to VSMOW (Vienna Standard Mean Ocean Water) on a scale such that {sup 2}H/{sup 1}H of SLAP (Standard Light Antartic Precipitation) is 0.572 times that of VSMOW, (ii) {sup 13}C/{sup 12}C relative ratios of all substances be expressed relative to VPDB (Vienna Peedee belemnite) on a scale such that {sup 13}C/{sup 12}C of NBS 19 carbonate is 1.00195 times that of VPDB, and (iii) {sup 18}O/{sup 16}O ratios of all substances be expressed relative to either VSMOW or VPDB on scales such that {sup 18}O/{sup 16}O of SLAP is 0.9445 times that of VSMOW. (Author)

  4. Purification of Ovine Respiratory Complex I Results in a Highly Active and Stable Preparation*

    Science.gov (United States)

    Letts, James A.; Degliesposti, Gianluca; Fiedorczuk, Karol; Skehel, Mark; Sazanov, Leonid A.

    2016-01-01

    NADH-ubiquinone oxidoreductase (complex I) is the largest (∼1 MDa) and the least characterized complex of the mitochondrial electron transport chain. Because of the ease of sample availability, previous work has focused almost exclusively on bovine complex I. However, only medium resolution structural analyses of this complex have been reported. Working with other mammalian complex I homologues is a potential approach for overcoming these limitations. Due to the inherent difficulty of expressing large membrane protein complexes, screening of complex I homologues is limited to large mammals reared for human consumption. The high sequence identity among these available sources may preclude the benefits of screening. Here, we report the characterization of complex I purified from Ovis aries (ovine) heart mitochondria. All 44 unique subunits of the intact complex were identified by mass spectrometry. We identified differences in the subunit composition of subcomplexes of ovine complex I as compared with bovine, suggesting differential stability of inter-subunit interactions within the complex. Furthermore, the 42-kDa subunit, which is easily lost from the bovine enzyme, remains tightly bound to ovine complex I. Additionally, we developed a novel purification protocol for highly active and stable mitochondrial complex I using the branched-chain detergent lauryl maltose neopentyl glycol. Our data demonstrate that, although closely related, significant differences exist between the biochemical properties of complex I prepared from ovine and bovine mitochondria and that ovine complex I represents a suitable alternative target for further structural studies. PMID:27672209

  5. Trends and problems on the studies by stable isotope ratio mass spectrometry for verifying the geographical origin of foods

    International Nuclear Information System (INIS)

    Korenaga, Takashi

    2013-01-01

    The multi-stable isotopic analysis method has employed to solve food authenticity problems. Stable isotope ratio of the light elements such as H, C, N, and O in food samples (e.g., rice, beef, and eel) were precisely analyzed by elemental analysis/isotope ratio mass spectrometry. Those samples were mainly taken from four different countries; Japan, United States of America, Australia, and China as comparison. All the rice samples were grown in the presence of either natural and or artificial fertilizer. The beef samples were taken from three different countries; Japan, United States of America, and Australia. Imported beef samples were also presented from the Ministry of Agriculture, Forestry and Fisheries, Japan, and compared with a correlation equation. The eel samples were taken from the three different countries and areas; Japan, China, and Taiwan. δX values showing some differences, all the Japanese food samples were clearly distinctive from the United States of America, Australia, China, and Taiwan samples. The results may be explained by the regional differences in isotope signatures of the climate, utilized nutrition, and/or quality of irrigation water among the farming countries. The statistical distinction could be one of the useful metrics to extract the food samples (rice, meat, fish, etc.) grown in Japan from those grown in the other countries. The dynamics analysis studies on stable isotopic behavior (i.e., Isotopomics) in human metabolism may be looking forward to establish a new science in near future. (author)

  6. On the cross-sensitivity between water vapor mixing ratio and stable isotope measurements of in-situ analyzers

    KAUST Repository

    Parkes, Stephen

    2015-04-01

    In recent years there has been an increasing amount of water vapor stable isotope data collected using in-situ instrumentation. A number of papers have characterized the performance of these in-situ analyzers and suggested methods for calibrating raw measurements. The cross-sensitivity of the isotopic measurements on the mixing ratio has been shown to be a major uncertainty and a variety of techniques have been suggested to characterize this inaccuracy. However, most of these are based on relating isotopic ratios to water vapor mixing ratios from in-situ analyzers when the mixing ratio is varied and the isotopic composition kept constant. An additional correction for the span of the isotopic ratio scale is then applied by measuring different isotopic standards. Here we argue that the water vapor cross-sensitivity arises from different instrument responses (span and offset) of the parent H2O isotope and the heavier isotopes, rather than spectral overlap that could cause a true variation in the isotopic ratio with mixing ratio. This is especially relevant for commercial laser optical instruments where absorption lines are well resolved. Thus, the cross-sensitivity determined using more conventional techniques is dependent on the isotopic ratio of the standard used for the characterization, although errors are expected to be small. Consequently, the cross-sensitivity should be determined by characterizing the span and zero offset of each isotope mixing ratio. In fact, this technique makes the span correction for the isotopic ratio redundant. In this work we model the impact of changes in the span and offset of the heavy and light isotopes and illustrate the impact on the cross-sensitivity of the isotopic ratios on water vapor. This clearly shows the importance of determining the zero offset for the two isotopes. The cross-sensitivity of the isotopic ratios on water vapor is then characterized by determining the instrument response for the individual isotopes for a

  7. On the cross-sensitivity between water vapor mixing ratio and stable isotope measurements of in-situ analyzers

    KAUST Repository

    Parkes, Stephen; Wang,  Lixin; McCabe, Matthew

    2015-01-01

    In recent years there has been an increasing amount of water vapor stable isotope data collected using in-situ instrumentation. A number of papers have characterized the performance of these in-situ analyzers and suggested methods for calibrating raw measurements. The cross-sensitivity of the isotopic measurements on the mixing ratio has been shown to be a major uncertainty and a variety of techniques have been suggested to characterize this inaccuracy. However, most of these are based on relating isotopic ratios to water vapor mixing ratios from in-situ analyzers when the mixing ratio is varied and the isotopic composition kept constant. An additional correction for the span of the isotopic ratio scale is then applied by measuring different isotopic standards. Here we argue that the water vapor cross-sensitivity arises from different instrument responses (span and offset) of the parent H2O isotope and the heavier isotopes, rather than spectral overlap that could cause a true variation in the isotopic ratio with mixing ratio. This is especially relevant for commercial laser optical instruments where absorption lines are well resolved. Thus, the cross-sensitivity determined using more conventional techniques is dependent on the isotopic ratio of the standard used for the characterization, although errors are expected to be small. Consequently, the cross-sensitivity should be determined by characterizing the span and zero offset of each isotope mixing ratio. In fact, this technique makes the span correction for the isotopic ratio redundant. In this work we model the impact of changes in the span and offset of the heavy and light isotopes and illustrate the impact on the cross-sensitivity of the isotopic ratios on water vapor. This clearly shows the importance of determining the zero offset for the two isotopes. The cross-sensitivity of the isotopic ratios on water vapor is then characterized by determining the instrument response for the individual isotopes for a

  8. Lead exposure in raptors from Japan and source identification using Pb stable isotope ratios.

    Science.gov (United States)

    Ishii, Chihiro; Nakayama, Shouta M M; Ikenaka, Yoshinori; Nakata, Hokuto; Saito, Keisuke; Watanabe, Yukiko; Mizukawa, Hazuki; Tanabe, Shinsuke; Nomiyama, Kei; Hayashi, Terutake; Ishizuka, Mayumi

    2017-11-01

    Lead (Pb) poisoning is widespread among raptors and water birds. In Japan, fragments of Pb ammunition are still found in endangered eagles although more than 10 years have passed since legislation regarding use of Pb ammunition was introduced. This study was performed to investigate Pb exposure in raptors from various locations in Japan. We measured hepatic and renal Pb concentrations and hepatic Pb isotope ratios of Steller's sea eagles (Haliaeetus pelagicus), white-tailed sea eagles (Haliaeetus albicilla), golden eagles (Aquila chrysaetos), and 13 other species (total 177 individuals) that were found dead, as well as blood samples from three eagles found in a weakened state during 1993-2015 from Hokkaido (northern part), Honshu (the main island), and Shikoku (a southern island) of Japan. In the present study in Hokkaido, one quarter of the sea eagles showed a high Pb concentration, suggesting exposure to abnormally high Pb levels and Pb poisoning. Pb isotope ratios indicated that endangered Steller's sea eagle and white-tailed sea eagle were poisoned by Pb ammunition that was used illegally in Hokkaido. In other areas of Japan, both surveillance and regulations were less extensive than in Hokkaido, but Pb poisoning in raptors was also noted. Therefore, Pb poisoning is still a serious problem in raptors in various areas of Japan due to accidental ingestion of materials containing Pb, especially Pb ammunition. Copyright © 2017. Published by Elsevier Ltd.

  9. Toward a simple, repeatable, non-destructive approach to measuring stable-isotope ratios of water within tree stems

    Science.gov (United States)

    Raulerson, S.; Volkmann, T.; Pangle, L. A.

    2017-12-01

    Traditional methodologies for measuring ratios of stable isotopes within the xylem water of trees involve destructive coring of the stem. A recent approach involves permanently installed probes within the stem, and an on-site assembly of pumps, switching valves, gas lines, and climate-controlled structure for field deployment of a laser spectrometer. The former method limits the possible temporal resolution of sampling, and sample size, while the latter may not be feasible for many research groups. We present results from initial laboratory efforts towards developing a non-destructive, temporally-resolved technique for measuring stable isotope ratios within the xylem flow of trees. Researchers have used direct liquid-vapor equilibration as a method to measure isotope ratios of the water in soil pores. Typically, this is done by placing soil samples in a fixed container, and allowing the liquid water within the soil to come into isotopic equilibrium with the headspace of the container. Water can also be removed via cryogenic distillation or azeotropic distillation, with the resulting liquid tested for isotope ratios. Alternatively, the isotope ratios of the water vapor can be directly measured using a laser-based water vapor isotope analyzer. Well-established fractionation factors and the isotope ratios in the vapor phase are then used to calculate the isotope ratios in the liquid phase. We propose a setup which would install a single, removable chamber onto a tree, where vapor samples could non-destructively and repeatedly be taken. These vapor samples will be injected into a laser-based isotope analyzer by a recirculating gas conveyance system. A major part of what is presented here is in the procedure of taking vapor samples at 100% relative humidity, appropriately diluting them with completely dry N2 calibration gas, and injecting them into the gas conveyance system without inducing fractionation in the process. This methodology will be helpful in making

  10. Method of stripping plutonium from tributyl phosphate solution which contains dibutyl phosphate-plutonium stable complexes

    International Nuclear Information System (INIS)

    Ochsenfeld, W.; Schmieder, H.

    1976-01-01

    Fast breeder fuel elements which have been highly burnt-up are reprocessed by extracting uranium and plutonium into an organic solution containing tributyl phosphate. The tributyl phosphate degenerates at least partially into dibutyl phosphate and monobutyl phosphate, which form stable complexes with tetravalent plutonium in the organic solution. This tetravalent plutonium is released from its complexed state and stripped into aqueous phase by contacting the organic solution with an aqueous phase containing tetravalent uranium. 6 claims, 1 drawing figure

  11. Modelling of the flow of stable air over a complex region

    CSIR Research Space (South Africa)

    Scholtz, MT

    1976-01-01

    Full Text Available The flow of stable air over a general region of complex topography and non-uniform surface temperature has been investigated. In order to gain further understanding of the motion of surface air, it was necessary to study the vertical structure...

  12. Complementary stable carbon isotope ratio and amount of substance measurements in sports anti-doping.

    Science.gov (United States)

    Cawley, Adam T; George, Adrian V

    2012-12-01

    The detection of steroids originating from synthetic precursors against a background of their chemically identical natural analogues has proven to be a significant challenge for doping control laboratories accredited by the World Anti-Doping Agency (WADA). The complementary application of gas chromatography-mass spectrometry (GC-MS) and gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) has been demonstrated to provide specific detection of endogenous steroid misuse for improved anti-doping analysis. Markers of synthetically derived steroids are reviewed on the basis of abnormal urinary excretions and low (13)C content. A combinatorial approach is presented for the interpretation of GC-MS and GC-C-IRMS data in the anti-doping context. This methodology can allow all relevant information concerning an individual's metabolism to be assessed in order to make an informed decision with respect to a doping violation. Copyright © 2012 John Wiley & Sons, Ltd.

  13. Source characterization using compound composition and stable carbon isotope ratio of PAHs in sediments from lakes, harbor, and shipping waterway

    International Nuclear Information System (INIS)

    Kim, Moonkoo; Kennicutt, Mahlon C.; Qian, Yaorong

    2008-01-01

    Molecular compositions and compound specific stable carbon isotope ratios of polycyclic aromatic hydrocarbons (PAH) isolated from sediments were used to characterize possible sources of contamination at an urban lake, a harbor, a shipping waterway, and a relatively undisturbed remote lake in the northwest United States. Total PAH concentrations in urban lake sediments ranged from 66.0 to 16,500 μg g -1 dry wt. with an average of 2600 μg g -1 , which is ∼ 50, 100, and 400 times higher on average than PAH in harbor (48 μg g -1 on average), shipping waterway (26 μg g -1 ), and remote lake (7 μg g -1 ) sediments, respectively. The PAH distribution patterns, methyl phenanthrene/phenanthrene ratios, and a pyrogenic index at the sites suggest a pyrogenic origin for PAHs. Source characterization using principal component analysis and various molecular indices including C2-dibenzothiophenes/C2-phenanthrenes, C3-dibenzothiophenes/C3-phenanthrenes, and C2-chrysenes/C2-phenanthrenes ratios, was able to differentiate PAH deposited in sediments from the four sites. The uniqueness of the source of the sediment PAHs from urban lake was also illustrated by compound specific stable carbon isotope analysis. It was concluded that urban lake sediments are accumulating PAH from sources that are unique from contamination detected at nearby sites in the same watershed

  14. Stable carbon isotopic composition of gasolines determined by isotope ratio monitoring gas chromatography mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Smallwood, B.J.; Philp, R.P.; Allen, J.D. [University of Oklahoma, Norman, OK (United States). School of Geology and Geophysics

    2002-07-01

    A large number of underground gasoline storage facilities in the United States continuously leak gasoline into the subsurface, which makes gasoline a major groundwater contaminant. Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) are used currently to characterize contaminated groundwater and soils. Correlations of contaminants with suspected source(s) are extremely difficult by these techniques because many gasolines have similar hydrocarbon distributions. The present study applied the technique of isotope ratio monitoring gas chromatography-mass spectrometry (irmGC-MS) to 19 gasoline samples from different areas of the USA. This allows a much better correlation of gasoline contaminants to source. Data obtained indicate a wide range of {sup {delta}}{sup 13}C values for 16 ubiquitous compounds in the gasolines. The majority of samples could be distinguished from each other on the basis of {sup {delta}}{sup 13}C hydrocarbon composition. The oxygenated additive methyl tertiary butyl ether (MTBE) was present in ten of the gasolines analyzed, and had a relatively narrow range of {sup {delta}}{sup 13}C values (-30.4 to -28.3 per mille). Preliminary investigations were also made to determine the extent of carbon isotopic fractionation after simple water washing and evaporation experiments. Results indicate that the majority of compounds did not undergo significant carbon isotopic fractionation as a result of these processes. (author)

  15. Relations between oxygen stable isotopic ratios in precipitation and relevant meteorological factors in southwest China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The correlations of isotopic ratios in precipitation with temperature, air pressure and humidity at dif- ferent altitudes, in southwest China, are analyzed. There appear marked negative correlations for the δ 18O in precipitation with precipitation amount, vapor pressure and atmospheric precipitable water (PW) at Mengzi, Simao and Tengchong stations on synoptic timescale; the marked negative correlations between the δ 18O in precipitation and the diurnal mean temperature at 400 hPa, 500 hPa, 700 hPa and 850 hPa are different from the temperature effect in middle-high-latitude inland. Moreover, the notable positive correlation between the δ 18O in precipitation and the dew-point deficit △Td at different altitudes is found at the three stations. On annual timescale, the annual precipitation amount weighted mean δ 18O display the negative correlations not only with annual precipitation but also with annual mean temperature at 500 hPa. It can be deduced that, in the years with abnormally strong summer monsoon, more warm and wet air from low-latitude oceans is transported northward along the vapor channel located in southwest China and generates abnormally strong rainfall on the way. Meanwhile, the ab- normally strong condensation process will release more condensed latent heat into atmosphere, and lead to the rise of atmospheric temperature during rainfall, but decline of the δ 18O in precipitation. On the contrary, in the years with abnormally weak summer monsoon, the abnormally weak condensation process will release less condensed latent heat into atmosphere, and lead to the decline of atmos- pheric temperature during rainfall, but increase of the δ 18O in precipitation.

  16. Novel proxies for reconstructing paleohydrology from ombrotrophic peatlands: biomarker and compound-specific H and C stable isotope ratios

    Science.gov (United States)

    Wang, J.; Nichols, J. E.; Huang, Y.

    2008-12-01

    Ombrotrophic peatlands are excellent archives for paleohydrologic information because they are hydrologically isolated from their surroundings. However, quantitative proxies for deciphering peatland archives are lacking. Here, we present development and application of novel organic geochemical methods for quantitative reconstruction of paleohydrology from the ombrotrophic sediments, and comparison of organic geochemical data with conventional paleoecological proxies. Application of these methods to the sediments of several North American and European peatlands has revealed significant changes in the hydroclimate throughout the Holocene. The plant assemblage living at the surface of the peatland is tightly controlled by surface moisture. Under wet conditions, Sphagnum mosses, with no active mechanism for drawing water from below the surface of the peatland, are dominant. During dry conditions, vascular plants are more productive relative to Sphagnum. A ratio of the abundance of two biomarkers representing Sphagnum and vascular plants sensitively records changes in hydrologic balance (Nichols et al., 2006, Org. Geochem. 37, 1505-1513). We have further developed stable isotope models to compute climate parameters from compound-specific H and C isotope ratios of biomarkers to create a more comprehensive climate reconstruction. Vascular plant leaf waxes carry the D/H ratio signature of precipitation that is little affected by evaporation, whereas the Sphagnum biomarker records isotopic ratios of the water at the peatland surface, which is strongly enriched by evaporation. Evaporation amount can be calculated using the differences between D/H ratios of the two types of biomarkers. C isotope ratios of Sphagnum biomarkers can also be used to quantify surface wetness. Methanotrophic bacteria live symbiotically with Sphagnum, providing isotopically light carbon for photosynthesis. These bacteria are more active when the Sphagnum is wet, thus providing more 13C-depleted CO2

  17. Stable isotope ratios of the atmospheric CH4, CO2 and N2O in Tokai-mura

    International Nuclear Information System (INIS)

    Porntepkasemsan, Boonsom; Andoh, Mariko A.; Amano, Hikaru

    2000-11-01

    This report presents the results and interpretation of stable isotope ratios of the atmospheric CH 4 , CO 2 and N 2 O from a variety of sources in Tokai-mura. The seasonal changes of δ 13 CH 4 , δ 13 CO 2 and δ 15 N 2 O were determined under in-situ conditions in four sampling sites and one control site. Such measurements are expected to provide a useful means of estimating the transport mechanisms of the three trace gases in the environment. These isotopic signatures were analyzed by Isotope Ratio Mass Spectrometer (IRMS, Micromass Isoprime). Our data showed the significant seasonal fluctuation in the Hosoura rice paddy during the entire growing season in 1999. Possible causes for the variation are postulated. Additional measurements on soil properties and on organic δ 13 C in rice plant are suggested. Cited outstanding original papers are summarized in the references. (author)

  18. Asymptotically stable fourth-order accurate schemes for the diffusion equation on complex shapes

    International Nuclear Information System (INIS)

    Abarbanel, S.; Ditkowski, A.

    1997-01-01

    An algorithm which solves the multidimensional diffusion equation on complex shapes to fourth-order accuracy and is asymptotically stable in time is presented. This bounded-error result is achieved by constructing, on a rectangular grid, a differentiation matrix whose symmetric part is negative definite. The differentiation matrix accounts for the Dirichlet boundary condition by imposing penalty-like terms. Numerical examples in 2-D show that the method is effective even where standard schemes, stable by traditional definitions, fail. The ability of the paradigm to be applied to arbitrary geometric domains is an important feature of the algorithm. 5 refs., 14 figs

  19. Development of a Method to Isolate Glutamic Acid from Foodstuffs for a Precise Determination of Their Stable Carbon Isotope Ratio.

    Science.gov (United States)

    Kobayashi, Kazuhiro; Tanaka, Masaharu; Yatsukawa, Yoichi; Tanabe, Soichi; Tanaka, Mitsuru; Ohkouchi, Naohiko

    2018-01-01

    Recent growing health awareness is leading to increasingly conscious decisions by consumers regarding the production and traceability of food. Stable isotopic compositions provide useful information for tracing the origin of foodstuffs and processes of food production. Plants exhibit different ratios of stable carbon isotopes (δ 13 C) because they utilized different photosynthetic (carbon fixation) pathways and grow in various environments. The origins of glutamic acid in foodstuffs can be differentiated on the basis of these photosynthetic characteristics. Here, we have developed a method to isolate glutamic acid in foodstuffs for determining the δ 13 C value by elemental analyzer-isotope-ratio mass spectrometry (EA/IRMS) without unintended isotopic fractionation. Briefly, following acid-hydrolysis, samples were defatted and passed through activated carbon and a cation-exchange column. Then, glutamic acid was isolated using preparative HPLC. This method is applicable to measuring, with a low standard deviation, the δ 13 C values of glutamic acid from foodstuffs derived from C3 and C4 plants and marine algae.

  20. Return and Risk of Pairs Trading Using a Simulation-Based Bayesian Procedure for Predicting Stable Ratios of Stock Prices

    Directory of Open Access Journals (Sweden)

    David Ardia

    2016-03-01

    Full Text Available We investigate the direct connection between the uncertainty related to estimated stable ratios of stock prices and risk and return of two pairs trading strategies: a conditional statistical arbitrage method and an implicit arbitrage one. A simulation-based Bayesian procedure is introduced for predicting stable stock price ratios, defined in a cointegration model. Using this class of models and the proposed inferential technique, we are able to connect estimation and model uncertainty with risk and return of stock trading. In terms of methodology, we show the effect that using an encompassing prior, which is shown to be equivalent to a Jeffreys’ prior, has under an orthogonal normalization for the selection of pairs of cointegrated stock prices and further, its effect for the estimation and prediction of the spread between cointegrated stock prices. We distinguish between models with a normal and Student t distribution since the latter typically provides a better description of daily changes of prices on financial markets. As an empirical application, stocks are used that are ingredients of the Dow Jones Composite Average index. The results show that normalization has little effect on the selection of pairs of cointegrated stocks on the basis of Bayes factors. However, the results stress the importance of the orthogonal normalization for the estimation and prediction of the spread—the deviation from the equilibrium relationship—which leads to better results in terms of profit per capital engagement and risk than using a standard linear normalization.

  1. Measurements of stable isotope ratios in milk samples from a farm placed in the mountains of Transylvania

    Energy Technology Data Exchange (ETDEWEB)

    Magdas, D. A., E-mail: gabriela.cristea@itim-cj.ro; Cristea, G., E-mail: gabriela.cristea@itim-cj.ro; Bot, A.; Puscas, R.; Radu, S.; Mirel, V. [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath Str., 400293 Cluj-Napoca (Romania); Cordea, D. V.; Mihaiu, M. [University of Agricultural Science and Veterinary Medicine, 3-5 Calea Manastur, 400372 Cluj-Napoca (Romania)

    2013-11-13

    Product origin is of great importance for consumers especially because its association in consumer's perception with food quality, freedom from disease or pollution. Stable isotope ratio analysis is a powerful technique in food authenticity and traceability control which has been introduced within the European wine industry to ensure authenticity of wine provenance and to detect adulteration. Isotopic ratios measurements have also been successfully to other food commodities like: fruit juices, honey and dairy foods. The δ{sup 18}O and δ{sup 2}H content in milk water reflects the isotope composition of the ground water drunk by animals. Seasonal effects are also very important: in summer, milk water contains higher δ{sup 18}O and δ{sup 2}H values due to the fresh plants that are ate by animals. Relative carbon stable isotope abundances in total milk reflect the isotopic composition of the diet fed to the dairy cows. In this study the hydrogen, oxygen and carbon isotopic composition of 15 milk samples coming from a unit placed in the mountains of Transylvania was investigated. The distribution of the obtained isotopic values was than discussed taking into account that all the animals were feed with the same type of forage and consumed water was taken from the same source.

  2. Measurements of stable isotope ratios in milk samples from a farm placed in the mountains of Transylvania

    International Nuclear Information System (INIS)

    Magdas, D. A.; Cristea, G.; Bot, A.; Puscas, R.; Radu, S.; Mirel, V.; Cordea, D. V.; Mihaiu, M.

    2013-01-01

    Product origin is of great importance for consumers especially because its association in consumer's perception with food quality, freedom from disease or pollution. Stable isotope ratio analysis is a powerful technique in food authenticity and traceability control which has been introduced within the European wine industry to ensure authenticity of wine provenance and to detect adulteration. Isotopic ratios measurements have also been successfully to other food commodities like: fruit juices, honey and dairy foods. The δ 18 O and δ 2 H content in milk water reflects the isotope composition of the ground water drunk by animals. Seasonal effects are also very important: in summer, milk water contains higher δ 18 O and δ 2 H values due to the fresh plants that are ate by animals. Relative carbon stable isotope abundances in total milk reflect the isotopic composition of the diet fed to the dairy cows. In this study the hydrogen, oxygen and carbon isotopic composition of 15 milk samples coming from a unit placed in the mountains of Transylvania was investigated. The distribution of the obtained isotopic values was than discussed taking into account that all the animals were feed with the same type of forage and consumed water was taken from the same source

  3. Stable water isotopologue ratios in fog and cloud droplets of liquid clouds are not size-dependent

    Science.gov (United States)

    Spiegel, J.K.; Aemisegger, F.; Scholl, M.; Wienhold, F.G.; Collett, J.L.; Lee, T.; van Pinxteren, D.; Mertes, S.; Tilgner, A.; Herrmann, H.; Werner, Roland A.; Buchmann, N.; Eugster, W.

    2012-01-01

    In this work, we present the first observations of stable water isotopologue ratios in cloud droplets of different sizes collected simultaneously. We address the question whether the isotope ratio of droplets in a liquid cloud varies as a function of droplet size. Samples were collected from a ground intercepted cloud (= fog) during the Hill Cap Cloud Thuringia 2010 campaign (HCCT-2010) using a three-stage Caltech Active Strand Cloud water Collector (CASCC). An instrument test revealed that no artificial isotopic fractionation occurs during sample collection with the CASCC. Furthermore, we could experimentally confirm the hypothesis that the δ values of cloud droplets of the relevant droplet sizes (μm-range) were not significantly different and thus can be assumed to be in isotopic equilibrium immediately with the surrounding water vapor. However, during the dissolution period of the cloud, when the supersaturation inside the cloud decreased and the cloud began to clear, differences in isotope ratios of the different droplet sizes tended to be larger. This is likely to result from the cloud's heterogeneity, implying that larger and smaller cloud droplets have been collected at different moments in time, delivering isotope ratios from different collection times.

  4. Stable water isotopologue ratios in fog and cloud droplets of liquid clouds are not size-dependent

    Directory of Open Access Journals (Sweden)

    J. K. Spiegel

    2012-10-01

    Full Text Available In this work, we present the first observations of stable water isotopologue ratios in cloud droplets of different sizes collected simultaneously. We address the question whether the isotope ratio of droplets in a liquid cloud varies as a function of droplet size. Samples were collected from a ground intercepted cloud (= fog during the Hill Cap Cloud Thuringia 2010 campaign (HCCT-2010 using a three-stage Caltech Active Strand Cloud water Collector (CASCC. An instrument test revealed that no artificial isotopic fractionation occurs during sample collection with the CASCC. Furthermore, we could experimentally confirm the hypothesis that the δ values of cloud droplets of the relevant droplet sizes (μm-range were not significantly different and thus can be assumed to be in isotopic equilibrium immediately with the surrounding water vapor. However, during the dissolution period of the cloud, when the supersaturation inside the cloud decreased and the cloud began to clear, differences in isotope ratios of the different droplet sizes tended to be larger. This is likely to result from the cloud's heterogeneity, implying that larger and smaller cloud droplets have been collected at different moments in time, delivering isotope ratios from different collection times.

  5. Spectral analysis software improves confidence in plant and soil water stable isotope analyses performed by isotope ratio infrared spectroscopy (IRIS).

    Science.gov (United States)

    West, A G; Goldsmith, G R; Matimati, I; Dawson, T E

    2011-08-30

    Previous studies have demonstrated the potential for large errors to occur when analyzing waters containing organic contaminants using isotope ratio infrared spectroscopy (IRIS). In an attempt to address this problem, IRIS manufacturers now provide post-processing spectral analysis software capable of identifying samples with the types of spectral interference that compromises their stable isotope analysis. Here we report two independent tests of this post-processing spectral analysis software on two IRIS systems, OA-ICOS (Los Gatos Research Inc.) and WS-CRDS (Picarro Inc.). Following a similar methodology to a previous study, we cryogenically extracted plant leaf water and soil water and measured the δ(2)H and δ(18)O values of identical samples by isotope ratio mass spectrometry (IRMS) and IRIS. As an additional test, we analyzed plant stem waters and tap waters by IRMS and IRIS in an independent laboratory. For all tests we assumed that the IRMS value represented the "true" value against which we could compare the stable isotope results from the IRIS methods. Samples showing significant deviations from the IRMS value (>2σ) were considered to be contaminated and representative of spectral interference in the IRIS measurement. Over the two studies, 83% of plant species were considered contaminated on OA-ICOS and 58% on WS-CRDS. Post-analysis, spectra were analyzed using the manufacturer's spectral analysis software, in order to see if the software correctly identified contaminated samples. In our tests the software performed well, identifying all the samples with major errors. However, some false negatives indicate that user evaluation and testing of the software are necessary. Repeat sampling of plants showed considerable variation in the discrepancies between IRIS and IRMS. As such, we recommend that spectral analysis of IRIS data must be incorporated into standard post-processing routines. Furthermore, we suggest that the results from spectral analysis be

  6. Purification of Ovine Respiratory Complex I Results in a Highly Active and Stable Preparation.

    Science.gov (United States)

    Letts, James A; Degliesposti, Gianluca; Fiedorczuk, Karol; Skehel, Mark; Sazanov, Leonid A

    2016-11-18

    NADH-ubiquinone oxidoreductase (complex I) is the largest (∼1 MDa) and the least characterized complex of the mitochondrial electron transport chain. Because of the ease of sample availability, previous work has focused almost exclusively on bovine complex I. However, only medium resolution structural analyses of this complex have been reported. Working with other mammalian complex I homologues is a potential approach for overcoming these limitations. Due to the inherent difficulty of expressing large membrane protein complexes, screening of complex I homologues is limited to large mammals reared for human consumption. The high sequence identity among these available sources may preclude the benefits of screening. Here, we report the characterization of complex I purified from Ovis aries (ovine) heart mitochondria. All 44 unique subunits of the intact complex were identified by mass spectrometry. We identified differences in the subunit composition of subcomplexes of ovine complex I as compared with bovine, suggesting differential stability of inter-subunit interactions within the complex. Furthermore, the 42-kDa subunit, which is easily lost from the bovine enzyme, remains tightly bound to ovine complex I. Additionally, we developed a novel purification protocol for highly active and stable mitochondrial complex I using the branched-chain detergent lauryl maltose neopentyl glycol. Our data demonstrate that, although closely related, significant differences exist between the biochemical properties of complex I prepared from ovine and bovine mitochondria and that ovine complex I represents a suitable alternative target for further structural studies. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  7. Simultaneous stable carbon isotopic analysis of wine glycerol and ethanol by liquid chromatography coupled to isotope ratio mass spectrometry.

    Science.gov (United States)

    Cabañero, Ana I; Recio, Jose L; Rupérez, Mercedes

    2010-01-27

    A novel procedure was established for the simultaneous characterization of wine glycerol and ethanol (13)C/(12)C isotope ratio, using liquid chromatography/isotope ratio mass spectrometry (LC-IRMS). Several parameters influencing separation of glycerol and ethanol from wine matrix were optimized. Results obtained for 35 Spanish samples exposed no significant differences and very strong correlations (r = 0.99) between the glycerol (13)C/(12)C ratios obtained by an alternative method (gas chromatography/isotope ratio mass spectrometry) and the proposed new methodology, and between the ethanol (13)C/(12)C ratios obtained by the official method (elemental analyzer/isotope ratio mass spectrometry) and the proposed new methodology. The accuracy of the proposed method varied from 0.01 to 0.19 per thousand, and the analytical precision was better than 0.25 per thousand. The new developed LC-IRMS method it is the first isotopic method that allows (13)C/(12)C determination of both analytes in the same run directly from a liquid sample with no previous glycerol or ethanol isolation, overcoming technical difficulties associated with complex sample treatment and improving in terms of simplicity and speed.

  8. Increasing volume and complexity of pediatric epilepsy surgery with stable seizure outcome between 2008 and 2014

    DEFF Research Database (Denmark)

    Barba, Carmen; Specchio, Nicola; Guerrini, Renzo

    2017-01-01

    Objective The objective of the study was to assess common practice in pediatric epilepsy surgery in Italy between 2008 and 2014. Methods A survey was conducted among nine Italian epilepsy surgery centers to collect information on presurgical and postsurgical evaluation protocols, volumes and type...... and facilities. Significance This survey reveals an increase in volume and complexity of pediatric epilepsy surgery in Italy between 2008 and 2014, associated with a stable seizure outcome....

  9. Cation-Cation Complexes of Pentavalent Uranyl: From Disproportionation Intermediates to Stable Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Mougel, Victor; Horeglad, Pawel; Nocton, Gregory; Pecaut, Jacques; Mazzanti, Marinella [CEA, INAC, SCIB, Laboratoire de Reconnaissance Ionique et Chimie de Coordination, CEA-Grenoble, 38054 GRENOBLE, Cedex 09 (France)

    2010-07-01

    Three new cation cation complexes of pentavalent uranyl, stable with respect to the disproportionation reaction, have been prepared from the reaction of the precursor [(UO{sub 2}py{sub 5})-(KI{sub 2}py{sub 2})]{sub n} (1) with the Schiff base ligands salen{sup 2-}, acacen{sup 2-}, and salophen{sup 2-} (H{sub 2}salen N, N'-ethylene-bis(salicylidene-imine), H{sub 2}acacen=-N, N'-ethylenebis(acetylacetone-imine), H{sub 2}salophen=N, N'-phenylene-bis(salicylidene-imine)). The preparation of stable complexes requires a careful choice of counter ions and reaction conditions. Notably the reaction of 1 with salophen{sup 2-} in pyridine leads to immediate disproportionation, but in the presence of [18]crown-6 ([18]C-6) a stable complex forms. The solid-state structure of the four tetra-nuclear complexes ([UO{sub 2}-(acacen)]{sub 4}[{mu}{sub 8}-]{sub 2}[K([18]C-6)(py)]{sub 2}) (3) and ([UO{sub 2}(acacen)](4)[{mu}{sub 8}-]).2[K([222])(py)] (4) ([UO{sub 2}(salophen)](4)[{mu}{sub 8}-K]{sub 2}[mu(5)-KI]{sub 2}[(K([18]C-6)]).2 [K([18]C-6)-(thf){sub 2}].2I (5), and ([UO{sub 2}(salen)(4)][{mu}{sub 8}-Rb]{sub 2}[Rb([18]C-6)]{sub 2}) (9) ([222] = [222]cryptand, py =pyridine), presenting a T-shaped cation cation interaction has been determined by X-ray crystallographic studies. NMR spectroscopic and UV/Vis studies show that the tetra-nuclear structure is maintained in pyridine solution for the salen and acacen complexes. Stable mononuclear complexes of pentavalent uranyl are also obtained by reduction of the hexavalent uranyl Schiff base complexes with cobaltocene in pyridine in the absence of coordinating cations. The reactivity of the complex [U{sup V}O{sub 2}(salen)(py)][Cp*{sub 2}Co] with different alkali ions demonstrates the crucial effect of coordinating cations on the stability of cation cation complexes. The nature of the cation plays a key role in the preparation of stable cation cation complexes. Stable tetra-nuclear complexes form in the presence of K

  10. Stable carbon isotope ratios: implications for the source of sediment carbon and for phytoplankton carbon assimilation in Lake Memphremagog, Quebec

    International Nuclear Information System (INIS)

    LaZerte, B.D.

    1983-01-01

    The stable carbon isotope (SCI) ratio of the sediment of Lake Memphremagog, Quebec is compared with that ot terrestrial sources and the phytoplankton to determine the relative proportion of allochthonous carbon incorporated into the sediments. Approximately 40-50% of the organic carbon in the main basins' pelagic sediment was terrestrial in origin, whereas up to 100% was terrestrial in littoral areas. The SCI method of determining the organic carbon source of sediments appears more reliable than the C/N method. A comparison of the SCI fractionation of the phytoplankton with laboratory cultures under different degrees of carbon limitation indicates that the phytoplankton of Lake Memphremagog are not carbon limited and fix carbon primarily by the C 3 pathway

  11. The application of stable carbon isotope ratios as water quality indicators in coastal areas of Karachi, Pakistan

    International Nuclear Information System (INIS)

    Qureshi, R.M.; Mashiatullah, A.; Javed, T.; Tasneem, M.A.; Sajjad, M.I.; Saleem, M.; Khan, S.H.; Rizvi, S.H.N.; Siddiqui, S.A.; Qari, R.

    1998-01-01

    Stable carbon isotope ratios (δ 13 C) of total dissolved inorganic carbon (TDIC), total inorganic and organic carbon in bottom sediments, as well as sea plants in polluted water sources, non-polluted Karachi Sea water and pollution recipients are used to elaborate pollution scenario of shallow marine environment off Karachi coast. These results are supplemented with stable isotope composition of nitrogen (δ 15 N) in seaweeds and mangroves, toxic/trace metal concentration in sea-bottom sediments, total Coliform bacterial population, electrical conductivity, temperature and turbidity. Isotopic data shows that the mangrove ecosystem and the tidal fluctuations play a key role in controlling contamination inventories in shallow sea water off Karachi coast, specifically the Manora Channel. The Karachi harbour zone is found to be the most heavily polluted marine site in Manora channel during high as well as low tide regimes. Significant concentrations of toxic metals such as Pb, Ni, Cr, Zn, V, U are observed in off-shore sediments of Karachi coast. The results show that sewage and industrial wastes are the main sources of heavy metal pollution in Karachi harbour, Manora Channel exit zone and the southeast coast. However, as compared to other coastal areas, the Karachi coast is moderately polluted. Studies suggest incorporation of quick remedial measures to combat pollution in shallow marine environments off Karachi Coast. (author)

  12. Effects of Water Vapor on the Data Quality of the Stable Oxygen Isotopic Ratio of Atmospheric Carbon Dioxide

    Science.gov (United States)

    Evans, C. U.; White, J. W.; Vaughn, B.; Tans, P. P.; Pardo, L.

    2007-12-01

    The stable oxygen isotopic ratio of carbon dioxide can potentially track fundamental indicators of environmental change such as the balance between photosynthesis and respiration on regional to global scales. The Stable Isotope Laboratory (SIL) at the Institute of Arctic and Alpine Research (INSTAAR), University of Colorado at Boulder, has measured the stable isotopes of atmospheric carbon dioxide from more than 60 NOAA/Earth System Research Laboratory (ESRL) air flask-sampling sites since the early 1990s. If air is sampled without drying, oxygen can exchange between carbon dioxide and water in the flasks, entirely masking the desired signal. An attempt to investigate how water vapor is affecting the δ18O signal is accomplished by comparing the SIL measurements with specific humidity, calculated from the National Climatic Data Center (NCDC) global integrated surface hourly temperature and dew point database, at the time of sampling. Analysis of sites where samples have been collected initially without drying, and subsequently with a drying kit, in conjunction with the humidity data, has led to several conclusions. Samples that initially appear isotopically unaltered, in that their δ18O values are within the expected range, are being subtly influenced by the water vapor in the air. At Bermuda and other tropical to semi-tropical sites, the 'wet' sampling values have a seasonal cycle that is strongly anti-correlated to the specific humidity, while the 'dry' values have a seasonal cycle that is shifted earlier than the specific humidity cycle by 1-2 months. The latter phasing is expected given the seasonal phasing between climate over the ocean and land, while the former is consistent with a small, but measurable isotope exchange in the flasks. In addition, we note that there is a strong (r > 0.96) correlation between the average specific humidity and the percent of rejected samples for 'wet' sampling. This presents an opportunity for determining a threshold of

  13. Elaboration of Stable and Antibody Functionalized Positively Charged Colloids by Polyelectrolyte Complexation between Chitosan and Hyaluronic Acid

    Directory of Open Access Journals (Sweden)

    Ramona C. Polexe

    2013-07-01

    Full Text Available In this study, we describe the elaboration of multifunctional positively charged polyelectrolyte complex (PEC nanoparticles, designed to be stable at physiological salt concentration and pH, for effective targeted delivery. These nanoparticles were obtained by charge neutralization between chitosan (CS as polycation and hyaluronic acid (HA as polyanion. We showed that the course of the complexation process and the physico-chemical properties of the resulting colloids were impacted by (i internal parameters such as the Degree of Acetylation (DA, i.e., the molar ration of acetyl glucosamine residues and molar mass of CS, the HA molar mass and (ii external parameters like the charge mixing ratio and the polymer concentrations. As a result, nonstoichiometric colloidal PECs were obtained in water or PBS (pH 7.4 and remained stable over one month. The polymer interactions were characterized by thermal analysis (DSC and TGA and the morphology was studied by scanning electron microscopy. A model antibody, anti-ovalbumine (OVA immunoglobulin A (IgA was sorbed on the particle surface in water and PBS quantitatively in 4 h. The CS-HA/IgA nanoparticles average size was between 425–665 nm with a positive zeta potential. These results pointed out that CS-HA can be effective carriers for use in targeted drug delivery.

  14. Identification of milk origin and process-induced changes in milk by stable isotope ratio mass spectrometry.

    Science.gov (United States)

    Scampicchio, Matteo; Mimmo, Tanja; Capici, Calogero; Huck, Christian; Innocente, Nadia; Drusch, Stephan; Cesco, Stefano

    2012-11-14

    Stable isotope values were used to develop a new analytical approach enabling the simultaneous identification of milk samples either processed with different heating regimens or from different geographical origins. The samples consisted of raw, pasteurized (HTST), and ultrapasteurized (UHT) milk from different Italian origins. The approach consisted of the analysis of the isotope ratio of δ¹³C and δ¹⁵N for the milk samples and their fractions (fat, casein, and whey). The main finding of this work is that as the heat processing affects the composition of the milk fractions, changes in δ¹³C and δ¹⁵N were also observed. These changes were used as markers to develop pattern recognition maps based on principal component analysis and supervised classification models, such as linear discriminant analysis (LDA), multivariate regression (MLR), principal component regression (PCR), and partial least-squares (PLS). The results give proof of the concept that isotope ratio mass spectroscopy can discriminate simultaneously between milk samples according to their geographical origin and type of processing.

  15. Freezing and fractionation: effects of preservation on carbon and nitrogen stable isotope ratios of some limnetic organisms.

    Science.gov (United States)

    Wolf, J Marshall; Johnson, Brett; Silver, Douglas; Pate, William; Christianson, Kyle

    2016-03-15

    Stable isotopes of carbon and nitrogen have become important natural tracers for studying food-web structure and function. Considerable research has demonstrated that chemical preservatives and fixatives shift the isotopic ratios of aquatic organisms. Much less is known about the effects of freezing as a preservation method although this technique is commonly used. We conducted a controlled experiment to test the effects of freezing (-10 °C) and flash freezing (–79 °C) on the carbon and nitrogen isotope ratios of zooplankton (Cladocera), Mysis diluviana and Rainbow Trout (Oncorhynchus mykiss). Subsamples (~0.5 mg) of dried material were analyzed for percentage carbon, percentage nitrogen, and the relative abundance of stable carbon and nitrogen isotopes (δ13C and δ15N values) using a Carlo Erba NC2500 elemental analyzer interfaced to a ThermoFinnigan MAT Delta Plus isotope ratio mass spectrometer. The effects of freezing were taxon-dependent. Freezing had no effect on the isotopic or elemental values of Rainbow Trout muscle. Effects on the δ13C and δ15N values of zooplankton and Mysis were statistically significant but small relative to typical values of trophic fractionation. The treatment-control offsets had larger absolute values for Mysis (δ13C: ≤0.76 ± 0.41‰, δ15N: ≤0.37 ± 0.16‰) than for zooplankton (δ13C: ≤0.12 ± 0.06‰, δ15N: ≤0.30 ± 0.27‰). The effects of freezing were more variable for the δ13C values of Mysis, and more variable for the δ15N values of zooplankton. Generally, both freezing methods reduced the carbon content of zooplankton and Mysis, but freezing had a negative effect on the %N of zooplankton and a positive effect on the %N of Mysis. The species-dependencies and variability of freezing effects on aquatic organisms suggest that more research is needed to understand the mechanisms responsible for freezing-related fractionation before standardized protocols for freezing as a preservation method can be adopted.

  16. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates.

    Science.gov (United States)

    Moerdijk-Poortvliet, Tanja C W; Schierbeek, Henk; Houtekamer, Marco; van Engeland, Tom; Derrien, Delphine; Stal, Lucas J; Boschker, Henricus T S

    2015-07-15

    We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ(13)C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although LC/IRMS is expected to be more accurate and precise, no direct comparison has been reported. GC/IRMS with the aldonitrile penta-acetate (ANPA) derivatisation method was compared with LC/IRMS without derivatisation. A large number of glucose standards and a variety of natural samples were analysed for five neutral carbohydrates at natural abundance as well as at (13)C-enriched levels. Gas chromatography/chemical ionisation mass spectrometry (GC/CIMS) was applied to check for incomplete derivatisation of the carbohydrate, which would impair the accuracy of the GC/IRMS method. The LC/IRMS technique provided excellent precision (±0.08‰ and ±3.1‰ at natural abundance and enrichment levels, respectively) for the glucose standards and this technique proved to be superior to GC/IRMS (±0.62‰ and ±19.8‰ at natural abundance and enrichment levels, respectively). For GC/IRMS measurements the derivatisation correction and the conversion of carbohydrates into CO2 had a considerable effect on the measured δ(13)C values. However, we did not find any significant differences in the accuracy of the two techniques over the full range of natural δ(13)C abundances and (13)C-labelled glucose. The difference in the performance of GC/IRMS and LC/IRMS diminished when the δ(13)C values were measured in natural samples, because the chromatographic performance and background correction became critical factors, particularly for LC/IRMS. The derivatisation of carbohydrates for the GC/IRMS method was complete. Although both LC/IRMS and GC/IRMS are reliable techniques for compound-specific stable carbon isotope analysis of carbohydrates (provided that derivatisation is complete and the

  17. Raman spectroscopic studies of isotopic diatomic molecules and a technique for measuring stable isotope ratios using Raman scattering

    International Nuclear Information System (INIS)

    Harney, R.C.

    1976-01-01

    A method for measuring stable isotope ratios using Raman scattering has been developed. This method consists of simultaneously counting photons scattered out of a high-intensity laser beam by different isotopically-substituted molecules. A number of studies of isotopic diatomic molecules have been made. The Q-branches of the Raman spectra of the isotopic molecules 14 N 15 N and 16 O 18 O were observed at natural abundance in nitrogen and oxygen samples. Comparison of the ratios of the intensities of the Q-branches of the major nitrogen and oxygen isotopic molecules with mass spectrometric determinations of the isotopic compositions yielded scattering cross sections of 14 N 15 N relative to 14 N 14 N and 16 O 18 O relative to 16 O 16 O. These cross section ratios differ from unity, a difference which can be explained by considering nuclear mass effects on the Franck-Condon factors of the molecular transitions. The measured intensities of the 14 N 15 N and 16 O 18 O Q-branches provided the baseline data needed to make the previously-mentioned extrapolation. High-resolution (approximately 0.15 cm -1 ) spectra of the Q-branches of 14 N 14 N and 16 O 16 O yielded a direct determination of α/sub e/ (the difference between the rotational constant in the ground and first excited vibrational states) for these molecules. The measured values are in excellent agreement with those obtained by other means. Complete Raman spectra (pure rotation, rotation-vibration, and high-resolution Q-branch) were obtained on a sample of pure 18 O 18 O. Analysis of this data yielded the molecular parameters: the equilibrium internuclear separation r/sub e/, the moment of inertia I/sub e/, and the energy parameters α/sub e/, B/sub e/, and ΔG/sub 1 / 2 /. These are in good agreement with data obtained by microwave spectroscopy

  18. Detection of prostate cancer with complexed PSA and complexed/total PSA ratio - is there any advantage?

    OpenAIRE

    Strittmatter, F; Stieber, P; Nagel, D; Füllhase, C; Walther, S; Stief, CG; Waidelich, R

    2011-01-01

    Abstract Objective To evaluate the performance of total PSA (tPSA), the free/total PSA ratio (f/tPSA), complexed PSA (cPSA) and the complexed/total PSA ratio (c/tPSA) in prostate cancer detection. Methods Frozen sera of 442 patients have been analysed for tPSA, free PSA (fPSA) and cPSA. 131 patients had prostate cancer and 311 patients benign prostatic hyperplasia. Results Differences in the distribution of the biomarkers were seen as follows: tPSA, cPSA and c/tPSA were significantly higher i...

  19. A Stable Coordination Complex of Rh(IV) in an N,O-Donor Environment

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, Shashi B. [Department of Chemistry, Yale University, 225 Prospect; Shopov, Dimitar Y. [Department of Chemistry, Yale University, 225 Prospect; Sharninghausen, Liam S. [Department of Chemistry, Yale University, 225 Prospect; Vinyard, David J. [Department of Chemistry, Yale University, 225 Prospect; Mercado, Brandon Q. [Department of Chemistry, Yale University, 225 Prospect; Brudvig, Gary W. [Department of Chemistry, Yale University, 225 Prospect; Crabtree, Robert H. [Department of Chemistry, Yale University, 225 Prospect

    2015-12-10

    We describe facial and meridional isomers of [RhIII(pyalk)3], as well as meridional [RhIV(pyalk)3]+ {pyalk =2-(2-pyridyl)-2-propanoate}, the first coordination complex in an N,O-donor environment to show a clean, reversible RhIII/IV redox couple and to have a stable Rh(IV) form, which we characterize by EPR and UV–visible spectroscopy as well as X-ray crystallography. The unprecedented stability of the Rh(IV) species is ascribed to the exceptional donor strength of the ligands, their oxidation resistance, and the meridional coordination geometry.

  20. Sup(99m)Tc-Sn-pyrophosphate complex. A stable, lyophilized radiopharmaceutical for skeletal scanning

    Energy Technology Data Exchange (ETDEWEB)

    Cvoric, J; Jovanovic, V; Bzenic, J [Institut za Nuklearne Nauke Boris Kidric, Belgrade (Yugoslavia); Stefanovic, Lj; Selir, Z [Institute for Tuberculosis and Pectoral Diseases, Radioisotope Applications, Sremska Kamenica (Yugoslavia)

    1978-01-01

    After a systematic investigation of the different phosphate polymers, viz. hexametaphosphate, tripolyphosphate, meta- and diphosphonate, pyrophosphate (Na/sub 4/P/sub 2/O/sub 7/) was selected for sceletal scintigraphy. A procedure has been developed for obtaining a sup(99m)Tc-labelled Sn(II): PyP complex by addition of a sterile, apyrogenic pertechnetate solution from a sup(99m)Tc-generator to a lyophilized solution of Sn(II)-tetrasodium phosphate. ''Kit'' composition was determined on the basis of biodynamic data obtained when the Sn/pyrophosphate ratio, pH and other parameters were varied. In vivo distribution of different sup(99m)Tc-Sn-pyrophosphate complexes permitted the selection of the most suitable complex for sceletal scanning. The investigated complex is being successfully applied in human scintigraphy of bones in the Laboratory for Radioisotope Applications of the Institute for Tubercolosis and Pectoral Diseases in Sremska Kamenica.

  1. A versatile method for simultaneous stable carbon isotope analysis of DNA and RNA nucleotides by liquid chromatography/isotope ratio mass spectrometry

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, T.C.W.; Brasser, J.; de Ruiter, G.; Houtekamer, M.; Bolhuis, H.; Stal, L.J.; Boschker, H.T.S.

    2014-01-01

    RATIONALELiquid chromatography/isotope ratio mass spectrometry (LC/IRMS) is currently the most accurate and precise technique for the measurement of compound-specific stable carbon isotope ratios (C-13/C-12) in biological metabolites, at their natural abundance. However, until now this technique

  2. Formation of stable and functional HIV-1 nucleoprotein complexes in vitro.

    Science.gov (United States)

    Tanchou, V; Gabus, C; Rogemond, V; Darlix, J L

    1995-10-06

    HIV genomic RNA resides within the nucleocapsid, in the interior of the virus, which serves to protect the RNA against nuclease degradation and to promote its reverse transcription. To investigate the role of nucleocapsid protein (NCp7) in the stability and replication of genomic RNA within the nucleocapsid, we used NCp7, reverse transcriptase (RT) and RNAs representing the 5' and 3' regions of the genome to reconstitute functional HIV-1 nucleocapsids. The nucleoprotein complexes generated in vitro were found to be stable, which, according to biochemical and genetic data, probably results from the tight binding of NCp7 molecules to the RNA and strong NCp7/NCp7 interactions. The nucleoprotein complexes efficiently protected viral RNA against RNase degradation and, at the same time, promoted viral DNA synthesis by RT. DNA strand transfer from the 5' to the 3' RNA template was very efficient in nucleoprotein complexes formed in the presence of both RNAs, but not when the RNAs were in separate complexes. These results indicate that the in vitro reconstituted HIV-1 nucleoprotein complexes function like virion nucleocapsids and thus provide a way to study at the molecular level this viral substructure and the synthesis of proviral DNA, and to search for new anti-HIV agents.

  3. Laser-based measurements of 18O/16O stable isotope ratios (δ18O in wine samples

    Directory of Open Access Journals (Sweden)

    Gupta M

    2013-09-01

    Full Text Available Manish Gupta,1 J Brian Leen,1 Elena Simone Franklin Berman,1 Aldo Ciambotti2 1Los Gatos Research, Mountain View, CA, USA; 2Consiglio per la Ricerca e la Sperimentazione in Agricoltura, Centro di Ricerca per l'Enologia, Asti, Italy Abstract: Wine counterfeiting is an international, multi-billion dollar issue, with some estimates suggesting that up to 5% of wines sold at auctions or secondary markets are fraudulent. Isotope ratio mass spectrometer (IRMS measurements of the 18O/16O stable isotope ratio (δ18O of water-in-wine have been used for wine authentication; however, these analyses are time-consuming and costly. In this preliminary study, off-axis integrated cavity output spectroscopy (OA-ICOS is used to quantify δ18O in wines. This laser-based method has been extensively used to study water isotopes for hydrological and medical applications. Recently, the development of a spectral contaminant identifier (SCI has extended the application of these OA-ICOS analyzers to contaminated water samples (eg, plant, soil, and leaf waters. Here, we utilize OA-ICOS with the SCI to characterize wine samples (9%–15% ethanol, and show that the laser-based instrument provides a δ18O measurement precision of ±0.07‰ (1σ and agrees with IRMS to within ±0.63‰ (1σ. Moreover, by training the SCI on isotopically-characterized wines, the agreement with IRMS improves to within ±0.30‰ (1σ. The utility of the instrument is demonstrated by measuring watered and mixed wines. The method presented here can be readily extended to address other food authentication applications. Keywords: wine isotopes, wine fraud, counterfeit wines, OA-ICOS

  4. Statistical methods for improving verification of claims of origin for Italian wines based on stable isotope ratios

    International Nuclear Information System (INIS)

    Dordevic, N.; Wehrens, R.; Postma, G.J.; Buydens, L.M.C.; Camin, F.

    2012-01-01

    Highlights: ► The assessment of claims of origin is of enormous economic importance for DOC and DOCG wines. ► The official method is based on univariate statistical tests of H, C and O isotopic ratios. ► We consider 5220 Italian wine samples collected in the period 2000–2010. ► Multivariate statistical analysis leads to much better specificity and easier detection of false claims of origin. ► In the case of multi-modal data, mixture modelling provides additional improvements. - Abstract: Wine derives its economic value to a large extent from geographical origin, which has a significant impact on the quality of the wine. According to the food legislation, wines can be without geographical origin (table wine) and wines with origin. Wines with origin must have characteristics which are essential due to its region of production and must be produced, processed and prepared, exclusively within that region. The development of fast and reliable analytical methods for the assessment of claims of origin is very important. The current official method is based on the measurement of stable isotope ratios of water and alcohol in wine, which are influenced by climatic factors. The results in this paper are based on 5220 Italian wine samples collected in the period 2000–2010. We evaluate the univariate approach underlying the official method to assess claims of origin and propose several new methods to get better geographical discrimination between samples. It is shown that multivariate methods are superior to univariate approaches in that they show increased sensitivity and specificity. In cases where data are non-normally distributed, an approach based on mixture modelling provides additional improvements.

  5. Statistical methods for improving verification of claims of origin for Italian wines based on stable isotope ratios

    Energy Technology Data Exchange (ETDEWEB)

    Dordevic, N.; Wehrens, R. [IASMA Research and Innovation Centre, Fondazione Edmund Mach, via Mach 1, 38010 San Michele all' Adige (Italy); Postma, G.J.; Buydens, L.M.C. [Radboud University Nijmegen, Institute for Molecules and Materials, Analytical Chemistry, P.O. Box 9010, 6500 GL Nijmegen (Netherlands); Camin, F., E-mail: federica.camin@fmach.it [IASMA Research and Innovation Centre, Fondazione Edmund Mach, via Mach 1, 38010 San Michele all' Adige (Italy)

    2012-12-13

    Highlights: Black-Right-Pointing-Pointer The assessment of claims of origin is of enormous economic importance for DOC and DOCG wines. Black-Right-Pointing-Pointer The official method is based on univariate statistical tests of H, C and O isotopic ratios. Black-Right-Pointing-Pointer We consider 5220 Italian wine samples collected in the period 2000-2010. Black-Right-Pointing-Pointer Multivariate statistical analysis leads to much better specificity and easier detection of false claims of origin. Black-Right-Pointing-Pointer In the case of multi-modal data, mixture modelling provides additional improvements. - Abstract: Wine derives its economic value to a large extent from geographical origin, which has a significant impact on the quality of the wine. According to the food legislation, wines can be without geographical origin (table wine) and wines with origin. Wines with origin must have characteristics which are essential due to its region of production and must be produced, processed and prepared, exclusively within that region. The development of fast and reliable analytical methods for the assessment of claims of origin is very important. The current official method is based on the measurement of stable isotope ratios of water and alcohol in wine, which are influenced by climatic factors. The results in this paper are based on 5220 Italian wine samples collected in the period 2000-2010. We evaluate the univariate approach underlying the official method to assess claims of origin and propose several new methods to get better geographical discrimination between samples. It is shown that multivariate methods are superior to univariate approaches in that they show increased sensitivity and specificity. In cases where data are non-normally distributed, an approach based on mixture modelling provides additional improvements.

  6. Distribution tactics for success in turbulent versus stable environments: A complexity theory approach

    Directory of Open Access Journals (Sweden)

    Roger Bruce Mason

    2013-11-01

    Full Text Available This article proposes that the external environment influences the choice of distribution tactics. Since businesses and markets are complex adaptive systems, using complexity theory to understand such environments is necessary, but it has not been widely researched. A qualitative case method using in-depth interviews investigated four successful, versus less successful, companies in turbulent versus stable environments. The results tentatively confirmed that the more successful company, in a turbulent market, sees distribution activities as less important than other aspects of the marketing mix, but uses them to stabilise customer relationships and to maintain distribution processes. These findings can benefit marketers by emphasising a new way to consider place activities. How marketers can be assisted, and suggestions for further research, are provided.

  7. Stable isotope ratio mass spectrometry and physical comparison for the forensic examination of grip-seal plastic bags.

    Science.gov (United States)

    Taylor, Erica; Carter, James F; Hill, Jenny C; Morton, Carolyn; Daeid, Niamh Nic; Sleeman, Richard

    2008-05-20

    Plastic bags are frequently used to package drugs, explosives and other contraband. There exists, therefore, a requirement in forensic casework to compare bags found at different locations. This is currently achieved almost exclusively by the use of physical comparisons such as birefringence patterns. This paper discusses some of the advantages and shortcomings of this approach, and presents stable isotope ratio mass spectrometry (IRMS) as a supplementary tool for effecting comparisons of this nature. Carbon and hydrogen isotopic data are presented for sixteen grip-seal plastic bags from a wide range of sources, in order to demonstrate the range of values which is likely to be encountered. Both isotopic and physical comparison (specifically birefringence) techniques are then applied to the analysis of rolls of bags from different manufacturing lots from a leading manufacturer. Both approaches are able to associate bags from a common production batch. IRMS can be applied to small fragments which are not amenable to physical comparisons, and is able to discriminate bags which could be confused using birefringence patterns alone. Similarly, in certain cases birefringence patterns discriminate bags with similar isotopic compositions. The two approaches are therefore complementary. When more than one isotopically distinct region exists within a bag (e.g. the grip-seal is distinct from the body) the ability to discriminate and associate bags is greatly increased.

  8. Stable carbon and oxygen isotope ratios of annual rings of pinus radiata provide an integrative record of canopy gas exchange

    International Nuclear Information System (INIS)

    Barbour, M.M.; Farquhar, G.D.

    2000-01-01

    Full text: Seasonal variation in δ 13 C and δ 18 O of cellulose from annual rings of Pinus radiata growing at each of three sites in New Zealand was measured. The three sites differed in annual water balance, temperature, and vapour pressure deficit, and these differences were reflected in cellulose δ 13 C and δ 18 O. Specific events such as drought or heavy rain were recorded as peaks and troughs in enrichment. A canopy-level combined photosynthesis and conductance model was linked to a model of soil water content and δ 18 O of xylem water to allow daily prediction of δ 13 C and δ 18 O of cellulose. A photosynthesis-weighted average of δ 13 C and δ 18 O was calculated for each sampling period. Each sample represented between 3 and 30 days, depending on stem growth rate. The timing and amplitude of changes in δ 13 C were predicted accurately by the model, while general seasonal patterns and event related peaks in δ 18 O enrichment were well predicted. These results suggest that stable isotope ratios of cellulose from annual rings reflect the canopy response to interactions between site-specific and seasonal variation in climatic conditions and soil water availability

  9. Stable carbon isotope ratios and intrinsic water-use efficiency of Miocene fossil leaves compared to modern congeners

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, J.D.; Zhang, J.; Rember, W.C.; Jennings, D.; Larson, P. (Univ. of Idaho, Moscow, ID (United States))

    1994-06-01

    Miocene fossil leaves of forest trees were extracted from the Clarkia, Idaho fossil beds and their stable carbon isotope ratios were analyzed. Fossils had higher lignin concentrations and lower cellulose concentrations that modern leaves due to diagenesis and the HF used to extract the fossils. Therefore, [delta][sup 13]C of extracted fossil lignin was compared to that of modern lignin. Fossil lignin [delta][sup 13]C was significantly different from that of congeneric modern leaves (paired t-test, P<0.0001), but was 1.9% less negative. Gymnosperms (Metasequoia, Taxodium) were less negative than angiosperms (e.g., Magnolia, Quercus, Acer, Persea), but no difference between evergreen and deciduous species was detected. Using published estimates of the concentration and [delta][sup 13]C of atmospheric CO[sub 2] during the Miocene was estimated the CO[sub 2] partial pressure gradient across the stomata (intrinsic water-use efficiency). Intrinsic water-use efficiency was at least 70% higher during this past [open quotes]greenhouse[close quotes] period than at present.

  10. Effect of baking and fermentation on the stable carbon and nitrogen isotope ratios of grain-based food.

    Science.gov (United States)

    Bostic, Joshua N; Palafox, Sherilyn J; Rottmueller, Marina E; Jahren, A Hope

    2015-05-30

    Isotope ratio mass spectrometry (IRMS) is used extensively to reconstruct general attributes of prehistoric and modern diets in both humans and animals. In order to apply these methods to the accurate determination of specific intakes of foods/nutrients of interest, the isotopic signature of individually consumed foods must be constrained. For example, 86% of the calories consumed in the USA are derived from processed and prepared foods, but the relationship between the stable isotope composition of raw ingredients and the resulting products has not been characterized. To examine the effect of common cooking techniques on the stable isotope composition of grain-based food items, we prepared yeast buns and sugar cookies from standardized recipes and measured bulk δ(13) C and δ(15) N values of samples collected throughout a 75 min fermentation process (buns) and before and after baking at 190°C (buns and cookies). Simple isotope mixing models were used to determine if the isotopic signatures of 13 multi-ingredient foods could be estimated from the isotopic signatures of their constituent raw ingredients. No variations in δ(13) C or δ(15) N values were detected between pre- and post-baked yeast buns (pre: -24.78‰/2.61‰, post: -24.75‰/2.74‰), beet-sugar cookies (pre: -24.48‰/3.84‰, post: -24.47‰/3.57‰), and cane-sugar cookies (pre: -19.07‰/2.97‰, post: -19.02‰/3.21‰), or throughout a 75 min fermentation process in yeast buns. Using isotopic mass balance equations, the δ(13) C/δ(15) N values of multi-ingredient foods were estimated from the isotopic composition of constituent raw ingredients to within 0.14 ± 0.13‰/0.24 ± 0.17‰ for gravimetrically measured recipes and 0.40 ± 0.38‰/0.58 ± 0.53‰ for volumetrically measured recipes. Two common food preparation techniques, baking and fermentation, do not substantially affect the carbon or nitrogen isotopic signature of grain-based foods. Mass-balance equations can be used to

  11. A 10-yr record of stable isotope ratios of hydrogen and oxygen in precipitation at Calgary, Alberta, Canada

    International Nuclear Information System (INIS)

    Peng, Haidong; Mayer, Bernhard; Krouse, H. Roy; Harris, Stuart

    2004-01-01

    Short-term (0.5-3 d) precipitation samples were collected from January 1992 to December 2001 in Calgary, Alberta, Canada, and the stable isotope ratios of hydrogen ( 2 H/ 1 H) and oxygen ( 18 O/ 16 O) for these samples were determined. The 10-yr amount-weighted average δ 2 H and δ 18 O values of precipitation were -136.1 per mill and -17.9 per mill, respectively. Consistent with IAEA established practice, the following local meteoric water line (LMWL) for Calgary was derived using amount-weighted monthly average δ 2 H and δ 18 O values: δ 2 H = 7.68 δ 18 O -0.21 (r 2 = 0.96, n= 104) . The correlation equation between δ 2 H and δ 18 O values from individual samples was found to be δ 2 H = 7.10 δ 18 O -13.64 (r 2 = 0.95, n= 839) , which is different from the LMWL, exhibiting lower slope and intercept values. A comparison of δ 2 H and δ 18 O correlation equations with temperature during precipitation events showed a trend of decreasing slopes and intercepts with increasing temperature. Our data suggest that this is caused by incorporation of moisture derived from evaporation from water bodies and soils along the storm paths and by secondary evaporation between the cloud base and the ground during precipitation events. These processes compromise the usefulness of d-excess values as an indicator for the meteorological conditions in the maritime source regions. The δ 18 O temperature dependence at Calgary was found to be ∼ 0.44 per mill/deg C. The study shows that short-term sampling of individual precipitation events yields valuable information, which is not obtainable by the widely used monthly collection programs

  12. A 10-yr record of stable isotope ratios of hydrogen and oxygen in precipitation at Calgary, Alberta, Canada

    Science.gov (United States)

    Peng, Haidong; Mayer, Bernhard; Harris, Stuart; Krouse, H. Roy

    2004-04-01

    Short-term (0.5 3 d) precipitation samples were collected from January 1992 to December 2001 in Calgary, Alberta, Canada, and the stable isotope ratios of hydrogen (2H/1H) and oxygen (18O/16O) for these samples were determined. The 10-yr amount-weighted average δ2H and δ18O values of precipitation were -136.1‰ and -17.9‰, respectively. Consistent with International Atomic Energy Agency (IAEA) established practice, the following local meteoric water line (LMWL) for Calgary was derived using amount-weighted monthly average δ2H and δ18O values: δ2H = 7.68 δ18O -0.21 (r2= 0.96, n= 104). The correlation equation between δ2H and δ18O values from individual samples was found to be δ2H = 7.10 δ18O -13.64 (r2= 0.95, n= 839), which is different from the LMWL, exhibiting lower slope and intercept values. A comparison of δ2H and δ18O correlation equations with temperature during precipitation events showed a trend of decreasing slopes and intercepts with increasing temperature. Our data suggest that this is caused by incorporation of moisture derived from evaporation from water bodies and soils along the storm paths and by secondary evaporation between the cloud base and the ground during precipitation events. These processes compromise the usefulness of d-excess values as an indicator for the meteorological conditions in the maritime source regions. The δ18O temperature dependence at Calgary was found to be 0.44‰°C1. The study shows that short-term sampling of individual precipitation events yields valuable information, which is not obtainable by the widely used monthly collection programs.

  13. Stable isotope ratio analysis of breastfeeding and weaning practices of children from medieval Fishergate House York, UK.

    Science.gov (United States)

    Burt, Nicole M

    2013-11-01

    Rib collagen of 51 juveniles and 11 adult females from the late medieval Fishergate House cemetery site (York, UK) were analyzed using nitrogen and carbon stable isotope ratio analysis to determine the weaning age for this population and to reconstruct diet. The juveniles' ages ranged from fetal to 5-6 years, while the females were of reproductive age. Previous researchers suggested that the children from Fishergate House might have been weaned later than the medieval British norm of 2 years, based on a mortality peak at 4-6 years of age. The results show weaning was complete by 2 years of age, agreeing with previous British weaning studies. The adult female δ(15) N values have a mean of 11.4‰ ± 1.1‰ and the δ(13) C values have a mean of -19.4‰ ± 0.4‰. These findings are consistent with previous isotopic studies of female diet in York during this period, though slightly lower. The weaned juvenile nitrogen values were found to be higher than the adult females (12.4‰ ± 1.0‰ for δ(15) N and -19.7‰ ± 0.5‰ for δ(13) C), which might indicate a dependence on higher trophic level proteins such as marine fish or pork. Marine fish is considered a high status food and children are considered low-status individuals at this time, making this a particularly interesting finding. Weaning does not appear to coincide with peak mortality, suggesting environment factors may be playing a larger role in child mortality at Fishergate House. Copyright © 2013 Wiley Periodicals, Inc.

  14. Carbon and nitrogen stable isotope ratios and mercury concentration in the scalp hair of residents from Taiji, a whaling town

    International Nuclear Information System (INIS)

    Endo, Tetsuya; Hayasaka, Moriaki; Hisamichi, Yohsuke; Kimura, Osamu; Haraguchi, Koichi

    2013-01-01

    Highlights: ► We analyzed δ 13 C, δ 15 N and Hg in hair from Japanese whale meat-eaters and non-eaters. ► The δ 15 N and δ 13 C values in whale meat-eaters were higher than those in non-eaters. ► The Hg concentration in whale meat-eaters was higher than that in non-eaters. ► A positive correlation was seen between δ 15 N and Hg in whale meat-eaters. ► Consumption of whale meat may increase δ 15 N, δ 13 C and Hg in the scalp hair. -- Abstract: We analyzed stable isotope ratios of carbon (δ 13 C) and nitrogen (δ 15 N) as well as mercury (Hg) concentration in the scalp hair of Japanese who consumed whale meat and those who did not, and investigated the relationships among the δ 13 C and δ 15 N values and Hg concentration. The average δ 15 N and δ 13 C values of whale meat-eaters (10.11‰ and −18.5‰) were significantly higher than those of non-eaters (9.28‰ and −18.9‰), respectively. The average Hg concentration of whale meat-eaters (20.6 μg/g) was significantly higher than that of non-eaters (2.20 μg/g). Significant positive correlations were found between the δ 13 C and δ 15 N values and between the δ 15 N value and Hg concentration in the hair of whale meat-eaters, while the correlation between the δ 15 N value and Hg concentration was not statistically significant in the non-eaters. The consumption of whale meat may increase Hg concentration as well as δ 15 N and δ 13 C values in scalp hair

  15. Potential of using stable nitrogen isotope ratio measurements to resolve fuel and thermal NOx in coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Chenggong Sun; Janos Lakatos; Colin E. Snape; Tony Fallick [University of Nottingham, Nottingham (United Kingdom). School of Chemical, Environmental and Mining Engineering (SChEME)

    2003-07-01

    In order to examine the potential of applying isotopic analysis to apportion NOx formation from different mechanisms, stable nitrogen isotope ratio measurements have been conducted on a number of thermal/prompt (diesel) and actual (coal) PF NO samples generated from a 1MW test facility at Powergen (UK), together with measurements on a range of pyrolysis and combustion chars obtained from a drop-tube reactor. A highly effective nitrogen-free sorbent, derived from white sugar with Mn as promoter, has been developed using an innovative procedure. This adsorbent has facilitated, for the first time, the determination of {delta}{sup 15}N values without background corrections. The isotopic data indicate that the thermal/prompt NOx collected during start-up with diesel as fuel has a {delta}{sup 15}N of close to 6.5(per thousand) compared to +15(per thousand) for the actual PF sample analysed. Thus, differences of up to ca. 20(per thousand) have been found to exist between thermal and PF fuel (char) NOx isotopic values. This augurs very well for the further development of the approach in order to help quantify the extent of thermal/prompt NOx formation in PF combustion. Measurements on chars have indicated that the extent of isotopic fractionation that occurs between coal-N and NOx from char is related to the reactivity of coals. Further, it would appear that much of the isotopic fractionation that occurs between coal nitrogen and fuel NO arises in the formation of char, although further fractionation can be inferred to occur during char combustion. In contrast, a lesser degree of isotopic fractionation is associated with the formation of thermal NO (ca. 6(per thousand)), atmospheric nitrogen having a value of 0(per thousand). 4 refs., 6 tabs.

  16. Stable isotope probing to study functional components of complex microbial ecosystems.

    Science.gov (United States)

    Mazard, Sophie; Schäfer, Hendrik

    2014-01-01

    This protocol presents a method of dissecting the DNA or RNA of key organisms involved in a specific biochemical process within a complex ecosystem. Stable isotope probing (SIP) allows the labelling and separation of nucleic acids from community members that are involved in important biochemical transformations, yet are often not the most numerically abundant members of a community. This pure culture-independent technique circumvents limitations of traditional microbial isolation techniques or data mining from large-scale whole-community metagenomic studies to tease out the identities and genomic repertoires of microorganisms participating in biological nutrient cycles. SIP experiments can be applied to virtually any ecosystem and biochemical pathway under investigation provided a suitable stable isotope substrate is available. This versatile methodology allows a wide range of analyses to be performed, from fatty-acid analyses, community structure and ecology studies, and targeted metagenomics involving nucleic acid sequencing. SIP experiments provide an effective alternative to large-scale whole-community metagenomic studies by specifically targeting the organisms or biochemical transformations of interest, thereby reducing the sequencing effort and time-consuming bioinformatics analyses of large datasets.

  17. Does the centre of mass remain stable during complex human postural equilibrium tasks in weightlessness?

    Science.gov (United States)

    Stapley, Paul; Pozzo, Thierry

    In normal gravity conditions the execution of voluntary movement involves the displacement of body segments as well as the maintenance of a stable reference value for equilibrium control. It has been suggested that centre of mass (CM) projection within the supporting base (BS) is the stabilised reference for voluntary action, and is conserved in weightlessness. The purpose of this study was to determine if the CM is stabilised during whole body reaching movements executed in weightlessness. The reaching task was conducted by two cosmonauts aboard the Russian orbital station MIR, during the Franco-Russian mission ALTAIR, 1993. Movements of reflective markers were recorded using a videocamera, successive images being reconstructed by computer every 40ms. The position of the CM, ankle joint torques and shank and thigh angles were computed for each subject pre- in- and post-flight using a 7-link mathematical model. Results showed that both cosmonauts adopted a backward leaning posture prior to reaching movements. Inflight, the CM was displaced throughout values in the horizontal axis three times those of pre-flight measures. In addition, ankle dorsi flexor torques inflight increased to values double those of pre- and post-flight tests. This study concluded that CM displacements do not remain stable during complex postural equilibrium tasks executed in weightlessness. Furthermore, in the absence of gravity, subjects changed their strategy for producing ankle torque during spaceflight from a forward to a backward leaning posture.

  18. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, Tanja C. W.; Schierbeek, Henk; Houtekamer, Marco; van Engeland, Tom; Derrien, Delphine; Stal, Lucas J.; Boschker, Henricus T. S.

    2015-01-01

    We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ(13)C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although

  19. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, T.C.W.; Schierbeek, H.; Houtekamer, M.; van Engeland, T.; Derrien, D.; Stal, L.J.; Boschker, H.T.S.

    2015-01-01

    We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of d13C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although

  20. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, T.C.W.; Schierbeek, H.; Houtekamer, M.; van Engeland, T.; Derrien, D.; Stal, L.J.; Boschker, H.T.S.

    2015-01-01

    Rationale: We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ13C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence,

  1. Permutation entropy and statistical complexity in characterising low-aspect-ratio reversed-field pinch plasma

    International Nuclear Information System (INIS)

    Onchi, T; Fujisawa, A; Sanpei, A; Himura, H; Masamune, S

    2017-01-01

    Permutation entropy and statistical complexity are measures for complex time series. The Bandt–Pompe methodology evaluates probability distribution using permutation. The method is robust and effective to quantify information of time series data. Statistical complexity is the product of Jensen–Shannon divergence and permutation entropy. These physical parameters are introduced to analyse time series of emission and magnetic fluctuations in low-aspect-ratio reversed-field pinch (RFP) plasma. The observed time-series data aggregates in a region of the plane, the so-called C – H plane, determined by entropy versus complexity. The C – H plane is a representation space used for distinguishing periodic, chaos, stochastic and noisy processes of time series data. The characteristics of the emissions and magnetic fluctuation change under different RFP-plasma conditions. The statistical complexities of soft x-ray emissions and magnetic fluctuations depend on the relationships between reversal and pinch parameters. (paper)

  2. Observations of molecular hydrogen mixing ratio and stable isotopic composition at the Cabauw tall tower in the Netherlands

    Science.gov (United States)

    Batenburg, A. M.; Popa, M. E.; Vermeulen, A. T.; van den Bulk, W. C. M.; Jongejan, P. A. C.; Fisher, R. E.; Lowry, D.; Nisbet, E. G.; Röckmann, T.

    2016-12-01

    Measurements of the stable isotopic composition (δD(H2) or δD) of atmospheric molecular hydrogen (H2) are a useful addition to mixing ratio (χ(H2)) measurements for understanding the atmospheric H2 cycle. δD datasets published so far consist mostly of observations at background locations. We complement these with observations from the Cabauw tall tower at the CESAR site, situated in a densely populated region of the Netherlands. Our measurements show a large anthropogenic influence on the local H2 cycle, with frequently occurring pollution events that are characterized by χ(H2) values that reach up to ≈1 ppm and low δD values. An isotopic source signature analysis yields an apparent source signature below -400‰, which is much more D-depleted than the fossil fuel combustion source signature commonly used in H2 budget studies. Two diurnal cycles that were sampled at a suburban site near London also show a more D-depleted source signature (≈-340‰), though not as extremely depleted as at Cabauw. The source signature of the Northwest European vehicle fleet may have shifted to somewhat lower values due to changes in vehicle technology and driving conditions. Even so, the surprisingly depleted apparent source signature at Cabauw requires additional explanation; microbial H2 production seems the most likely cause. The Cabauw tower site also allowed us to sample vertical profiles. We found no decrease in χ(H2) at lower sampling levels (20 and 60 m) with respect to higher sampling levels (120 and 200 m). There was a significant shift to lower median δD values at the lower levels. This confirms the limited role of soil uptake around Cabauw, and again points to microbial H2 production during an extended growing season, as well as to possible differences in average fossil fuel combustion source signature between the different footprint areas of the sampling levels. So, although knowledge of the background cycle of H2 has improved over the last decade, surprising

  3. Diet and habitat of the saiga antelope during the late Quaternary using stable carbon and nitrogen isotope ratios

    Science.gov (United States)

    Jürgensen, Jonathan; Drucker, Dorothée G.; Stuart, Anthony J.; Schneider, Matthias; Buuveibaatar, Bayarbaatar; Bocherens, Hervé

    2017-03-01

    Saiga antelope (Saiga tatarica) is one of the typical late Pleistocene species of the cold and arid mammoth steppe that covered a large area of northern hemisphere. The species is currently endangered and persists only in small areas of Central Asian steppe and desert ecosystems. The investigation of the ecology of the Pleistocene saiga using stable isotope ratios (δ13C, δ15N) aimed to decipher how different their diet and habitat were from those observed nowadays in relict populations. Up to 76 samples of bone collagen of ancient saiga from Western Europe, Siberia and Eastern Beringia were analysed and compared with 52 samples of hair and bone collagen of modern specimens from Kazahkstan, Russia and Mongolia. The δ13C values of the ancient saiga do not exhibit a clear trend over time. They cover the same range of values as the modern ones, from a C3-dominated to a C3-C4-dominated mixed diet (including probably Chenopodiaceae). In contrast, the δ15N values of fossil saigas are more variable and lower on average than the extant ones. The lowest δ15N values of ancient saiga are found around the Last Glacial Maximum, reflecting the influence of the cold conditions at that time. On the other hand, fossil saiga occupying the same regions as the historical and modern populations exhibit high δ15N values similar to the modern ones, confirming ecological continuity over time. Modern saiga is thus occupying just one of its potential diverse habitats they used in the past. Therefore, the extant saiga is not a refugee species confined to a suboptimal habitat. During the late Pleistocene, the saiga occupied a separate niche compared with the other ungulates of the mammoth steppe. However, this species could also adapt to a lichen-dominated diet normally seen in reindeer, leading to an isotopic overlap between the two species in south-western France and Alaska around the Last Glacial Maximum. This adaptation allowed a geographical expansion that does not correspond to a

  4. New glyme-cyclic imide lithium salt complexes as thermally stable electrolytes for lithium batteries

    Science.gov (United States)

    Tamura, Takashi; Hachida, Takeshi; Yoshida, Kazuki; Tachikawa, Naoki; Dokko, Kaoru; Watanabe, Masayoshi

    New glyme-Li salt complexes were prepared by mixing equimolar amounts of a novel cyclic imide lithium salt LiN(C 2F 4S 2O 4) (LiCTFSI) and a glyme (triglyme (G3) or tetraglyme (G4)). The glyme-Li salt complexes, [Li(G3)][CTFSI] and [Li(G4)][CTFSI], are solid and liquid, respectively, at room temperature. The thermal stability of [Li(G4)][CTFSI] is much higher than that of pure G4, and the vapor pressure of [Li(G4)][CTFSI] is negligible at temperatures lower than 100 °C. Although the viscosity of [Li(G4)][CTFSI] is high (132.0 mPa s at 30 °C), because of its high molar concentration (ca. 3 mol dm -3), its ionic conductivity at 30 °C is relatively high, i.e., 0.8 mS cm -1, which is slightly lower than that of a conventional organic electrolyte solution (1 mol dm -3 LiTFSI dissolved in propylene carbonate). The self-diffusion coefficients of a Li + cation, a CTFSI - anion, and a glyme molecule were measured by the pulsed gradient spin-echo NMR method (PGSE-NMR). The ionicity (dissociativity) of [Li(G4)][CTFSI] at 30 °C is ca. 0.5, as estimated from the PGSE-NMR diffusivity measurements and the ionic conductivity measurements. Results of linear sweep voltammetry revealed that [Li(G4)][CTFSI] is electrochemically stable in an electrode potential range of 0-4.5 V vs. Li/Li +. The reversible deposition-stripping behavior of lithium was observed by cyclic voltammetry. The [LiCoO 2|[Li(G4)][CTFSI]|Li metal] cell showed a stable charge-discharge cycling behavior during 50 cycles, indicating that the [Li(G4)][CTFSI] complex is applicable to a 4 V class lithium secondary battery.

  5. Biochemical principles underlying the stable maintenance of LTP by the CaMKII/NMDAR complex.

    Science.gov (United States)

    Lisman, John; Raghavachari, Sridhar

    2015-09-24

    Memory involves the storage of information at synapses by an LTP-like process. This information storage is synapse specific and can endure for years despite the turnover of all synaptic proteins. There must, therefore, be special principles that underlie the stability of LTP. Recent experimental results suggest that LTP is maintained by the complex of CaMKII with the NMDAR. Here we consider the specifics of the CaMKII/NMDAR molecular switch, with the goal of understanding the biochemical principles that underlie stable information storage by synapses. Consideration of a variety of experimental results suggests that multiple principles are involved. One switch requirement is to prevent spontaneous transitions from the off to the on state. The highly cooperative nature of CaMKII autophosphorylation by Ca(2+) (Hill coefficient of 8) and the fact that formation of the CaMKII/NMDAR complex requires release of CaMKII from actin are mechanisms that stabilize the off state. The stability of the on state depends critically on intersubunit autophosphorylation, a process that restores any loss of pT286 due to phosphatase activity. Intersubunit autophosphorylation is also important in explaining why on state stability is not compromised by protein turnover. Recent evidence suggests that turnover occurs by subunit exchange. Thus, stability could be achieved if a newly inserted unphosphorylated subunit was autophosphorylated by a neighboring subunit. Based on other recent work, we posit a novel mechanism that enhances the stability of the on state by protection of pT286 from phosphatases. We posit that the binding of the NMNDAR to CaMKII forces pT286 into the catalytic site of a neighboring subunit, thereby protecting pT286 from phosphatases. A final principle concerns the role of structural changes. The binding of CaMKII to the NMDAR may act as a tag to organize the binding of further proteins that produce the synapse enlargement that underlies late LTP. We argue that these

  6. Stable carbon isotope analyses of nanogram quantities of particulate organic carbon (pollen) with laser ablation nano combustion gas chromatography/isotope ratio mass spectrometry

    NARCIS (Netherlands)

    van Roij, Linda; Sluijs, Appy; Laks, Jelmer J.; Reichart, Gert-Jan

    2017-01-01

    Rationale: Analyses of stable carbon isotope ratios (δ13C values) of organic and inorganic matter remains have been instrumental for much of our understanding of present and past environmental and biological processes. Until recently, the analytical window of such analyses has been limited to

  7. On the interconnection of stable protein complexes: inter-complex hubs and their conservation in Saccharomyces cerevisiae and Homo sapiens networks.

    Science.gov (United States)

    Guerra, Concettina

    2015-01-01

    Protein complexes are key molecular entities that perform a variety of essential cellular functions. The connectivity of proteins within a complex has been widely investigated with both experimental and computational techniques. We developed a computational approach to identify and characterise proteins that play a role in interconnecting complexes. We computed a measure of inter-complex centrality, the crossroad index, based on disjoint paths connecting proteins in distinct complexes and identified inter-complex hubs as proteins with a high value of the crossroad index. We applied the approach to a set of stable complexes in Saccharomyces cerevisiae and in Homo sapiens. Just as done for hubs, we evaluated the topological and biological properties of inter-complex hubs addressing the following questions. Do inter-complex hubs tend to be evolutionary conserved? What is the relation between crossroad index and essentiality? We found a good correlation between inter-complex hubs and both evolutionary conservation and essentiality.

  8. Ratio of total-to-selective extinction in the Taurus dark cloud complex

    International Nuclear Information System (INIS)

    Vrba, F.J.; Rydgren, A.E.; Space Telescope Science Institute, Baltimore, MD)

    1985-01-01

    UBVRI and JHK photometry, as well as spectral classifications are presented for seven reddened early-type field stars that are observed through the Taurus dark cloud complex. The ratio of total-to-selective extinction is derived for each star by the color-difference method. For six stars with absolute magnitudes in violet of more than 1.7 and less than 3.2 mag, a normal ratio R of total-to-selective extinction of about 3.1 is found. The mildly anomalous R value of about 3.5 for the well-studied star HD 29647 was also confirmed. The results provide further evidence that the interstellar extinction law in the Taurus dark cloud complex is basically normal for lines of sight with absolute magnitudes in violet of less than 3 mag. 24 references

  9. Estimation of food composition of Hodotermes mossambicus (Isoptera: Hodotermitidae) based on observations and stable carbon isotope ratios

    CSIR Research Space (South Africa)

    Symes, CT

    2011-04-01

    Full Text Available , observations (93.8%) and stable isotopes (92.6%), no significant differ- ence was recognized (t-test dependent samples, t = 0.84, P = 0.46). Discussion Observations A widely used method of studying feeding habits in termites is by assessing the choice.... Canadian Journal of Zoology, 78, 1?27. LaFage, J.P. and Nutting, W.L. (1978) Food and feeding habits of termites. Nutrient Dynamics of Termites (ed. M.V. Brian), pp. 165?232. Cambridge University Press, Cambridge. McKechnie, A.E. (2004) Stable isotopes...

  10. Carbon and nitrogen stable isotope ratios of pelagic zooplankton elucidate ecohydrographic features in the oligotrophic Red Sea

    KAUST Repository

    Kü rten, Benjamin; Al-Aidaroos, Ali M.; Kurten, Saskia; El-Sherbiny, Mohsen M.; Devassy, Reny P.; Struck, Ulrich; Zarokanellos, Nikolaos; Jones, Burton; Hansen, Thomas; Bruss, Gerd; Sommer, Ulrich

    2015-01-01

    Although zooplankton occupy key roles in aquatic biogeochemical cycles, little is known about the pelagic food web and trophodynamics of zooplankton in the Red Sea. Natural abundance stable isotope analysis (SIA) of carbon (δ13C) and N (δ15N) is one

  11. Tracing anthropogenic Hg and Pb input using stable Hg and Pb isotope ratios in sediments of the central Portuguese Margin

    NARCIS (Netherlands)

    Mil-Holmens, M.; Blum, J.; Canário, J.; Caetano, M.; Costa, A.M.; Lebreiro, S.M.; Trancoso, M.; Richter, T.O.; de Stigter, H.; Johnson, M.; Branco, V.; Cesário, R.; Mouro, F.; Mateus, M.; Boer, W.; Melo, Z.

    2013-01-01

    Three short marine sediment cores from the Cascais Submarine Canyon (CSC; cores 252-32 and 252-35) and the Estremadura Spur (core 252-16) on the central Portuguese Margin were analysed for Hg, Pb, Al, and Mn concentrations, and both Pb and Hg stable isotope compositions, in order to reconstruct

  12. Variation in carbon and nitrogen stable isotope ratios in flight feathers of a moulting White-bellied Sunbird Cinnyris talatala

    CSIR Research Space (South Africa)

    Symes, CT

    2011-11-01

    Full Text Available The authors measured d13C and d15N isotope signatures in flight feathers of a White-bellied Sunbird to assess the value of using stable isotopes of feathers in avian dietary studies. Significant variation in d13C and d15N isotope values of flight...

  13. Effect of cyclodextrin complexation on the aqueous solubility and solubility/dose ratio of praziquantel.

    Science.gov (United States)

    Maragos, Stratos; Archontaki, Helen; Macheras, Panos; Valsami, Georgia

    2009-01-01

    Praziquantel (PZQ), the primary drug of choice in the treatment of schistosomiasis, is a highly lipophilic drug that possesses high permeability and low aqueous solubility and is, therefore, classified as a Class II drug according to the Biopharmaceutics Classification System (BCS). In this work, beta-cyclodextrin (beta-CD) and hydroxypropyl-beta-cyclodextrin (HP-beta-CD) were used in order to determine whether increasing the aqueous solubility of a drug by complexation with CDs, a BCS-Class II compound like PZQ could behave as BCS-Class I (highly soluble/highly permeable) drug. Phase solubility and the kneading and lyophilization techniques were used for inclusion complex preparation; solubility was determined by UV spectroscopy. The ability of the water soluble polymer polyvinylpyrolidone (PVP) to increase the complexation and solubilization efficiency of beta-CD and HP-beta-CD for PZQ was examined. Results showed significant improvement of PZQ solubility in the presence of both cyclodextrins but no additional effect in the presence of PVP. The solubility/dose ratios values of PZQ-cyclodextrin complexes calculated considering the low (150 mg) and the high dose (600 mg) of PZQ, used in practice, indicate that PZQ complexation with CDs may result in drug dosage forms that would behave as a BCS-Class I depending on the administered dose.

  14. Seasonal variation in marine C:N:P stoichiometry: can the composition of seston explain stable Redfield ratios?

    Directory of Open Access Journals (Sweden)

    H. Frigstad

    2011-10-01

    Full Text Available Seston is suspended particulate organic matter, comprising a mixture of autotrophic, heterotrophic and detrital material. Despite variable proportions of these components, marine seston often exhibits relatively small deviations from the Redfield ratio (C:N:P = 106:16:1. Two time-series from the Norwegian shelf in Skagerrak are used to identify drivers of the seasonal variation in seston elemental ratios. An ordination identified water mass characteristics and bloom dynamics as the most important drivers for determining C:N, while changes in nutrient concentrations and biomass were most important for the C:P and N:P relationships. There is no standardized method for determining the functional composition of seston and the fractions of POC, PON and PP associated with phytoplankton, therefore any such information has to be obtained by indirect means. In this study, a generalized linear model was used to differentiate between the live autotrophic and non-autotrophic sestonic fractions, and for both stations the non-autotrophic fractions dominated with respective annual means of 76 and 55%. This regression model approach builds on assumptions (e.g. constant POC:Chl-a ratio and the robustness of the estimates were explored with a bootstrap analysis. In addition the autotrophic percentage calculated from the statistical model was compared with estimated phytoplankton carbon, and the two independent estimates of autotrophic percentage were comparable with similar seasonal cycles. The estimated C:nutrient ratios of live autotrophs were, in general, lower than Redfield, while the non-autotrophic C:nutrient ratios were higher than the live autotrophic ratios and above, or close to, the Redfield ratio. This is due to preferential remineralization of nutrients, and the P content mainly governed the difference between the sestonic fractions. Despite the seasonal variability in seston composition and the generally low contribution of autotrophic

  15. Variation of strontium stable isotope ratios and origins of strontium in Japanese vegetables and comparison with Chinese vegetables.

    Science.gov (United States)

    Aoyama, Keisuke; Nakano, Takanori; Shin, Ki-Cheol; Izawa, Atsunobu; Morita, Sakie

    2017-12-15

    To evaluate the utility of 87 Sr/ 86 Sr ratio for determining the geographical provenance of vegetables, we compared 87 Sr/ 86 Sr ratios and Sr concentrations in five vegetable species grown in Japan and China, and we also examined the relationships between 87 Sr/ 86 Sr ratios in vegetables, the soil-exchangeable pool, irrigation water, and fertilizer from 20 Japanese agricultural areas. The vegetable 87 Sr/ 86 Sr ratios in Japan were similar for all species within a given agricultural area, but tended to be low in northeast Japan and high in southwest Japan. The median 87 Sr/ 86 Sr ratio in Japanese vegetables was similar to that in fertilizer, suggesting that in addition to rock-derived Sr, vegetables contain Sr derived from fertilizers. In most cases, the 87 Sr/ 86 Sr ratios for the Japanese and Chinese vegetables differed by approximately 0.710. Linear discriminant analysis using both 87 Sr/ 86 Sr and the Sr concentration allowed more accurate discrimination between vegetables from the two countries. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Efficient estimators for likelihood ratio sensitivity indices of complex stochastic dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Arampatzis, Georgios; Katsoulakis, Markos A.; Rey-Bellet, Luc [Department of Mathematics and Statistics, University of Massachusetts, Amherst, Massachusetts 01003 (United States)

    2016-03-14

    We demonstrate that centered likelihood ratio estimators for the sensitivity indices of complex stochastic dynamics are highly efficient with low, constant in time variance and consequently they are suitable for sensitivity analysis in long-time and steady-state regimes. These estimators rely on a new covariance formulation of the likelihood ratio that includes as a submatrix a Fisher information matrix for stochastic dynamics and can also be used for fast screening of insensitive parameters and parameter combinations. The proposed methods are applicable to broad classes of stochastic dynamics such as chemical reaction networks, Langevin-type equations and stochastic models in finance, including systems with a high dimensional parameter space and/or disparate decorrelation times between different observables. Furthermore, they are simple to implement as a standard observable in any existing simulation algorithm without additional modifications.

  17. Development of routines for simultaneous in situ chemical composition and stable Si isotope ratio analysis by femtosecond laser ablation inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Frick, Daniel A., E-mail: dfrick@gfz-potsdam.de [GFZ German Research Centre for Geosciences, 14473 Potsdam (Germany); Schuessler, Jan A. [GFZ German Research Centre for Geosciences, 14473 Potsdam (Germany); Blanckenburg, Friedhelm von [GFZ German Research Centre for Geosciences, 14473 Potsdam (Germany); Institute of Geological Science, Freie Universität Berlin, 12249 Berlin (Germany)

    2016-09-28

    Stable metal (e.g. Li, Mg, Ca, Fe, Cu, Zn, and Mo) and metalloid (B, Si, Ge) isotope ratio systems have emerged as geochemical tracers to fingerprint distinct physicochemical reactions. These systems are relevant to many Earth Science questions. The benefit of in situ microscale analysis using laser ablation (LA) over bulk sample analysis is to use the spatial context of different phases in the solid sample to disclose the processes that govern their chemical and isotopic compositions. However, there is a lack of in situ analytical routines to obtain a samples' stable isotope ratio together with its chemical composition. Here, we evaluate two novel analytical routines for the simultaneous determination of the chemical and Si stable isotope composition (δ{sup 30}Si) on the micrometre scale in geological samples. In both routines, multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) is combined with femtosecond-LA, where stable isotope ratios are corrected for mass bias using standard-sample-bracketing with matrix-independent calibration. The first method is based on laser ablation split stream (LASS), where the laser aerosol is split and introduced simultaneously into both the MC-ICP-MS and a quadrupole ICP-MS. The second method is based on optical emission spectroscopy using direct observation of the MC-ICP-MS plasma (LA-MC-ICP-MS|OES). Both methods are evaluated using international geological reference materials. Accurate and precise Si isotope ratios were obtained with an uncertainty typically better than 0.23‰, 2SD, δ{sup 30}Si. With both methods major element concentrations (e.g., Na, Al, Si, Mg, Ca) can be simultaneously determined. However, LASS-ICP-MS is superior over LA-MC-ICP-MS|OES, which is limited by its lower sensitivity. Moreover, LASS-ICP-MS offers trace element analysis down to the μg g{sup −1}-range for more than 28 elements due to lower limits of detection, and with typical uncertainties better than 15%. For in situ

  18. Development of routines for simultaneous in situ chemical composition and stable Si isotope ratio analysis by femtosecond laser ablation inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Frick, Daniel A.; Schuessler, Jan A.; Blanckenburg, Friedhelm von

    2016-01-01

    Stable metal (e.g. Li, Mg, Ca, Fe, Cu, Zn, and Mo) and metalloid (B, Si, Ge) isotope ratio systems have emerged as geochemical tracers to fingerprint distinct physicochemical reactions. These systems are relevant to many Earth Science questions. The benefit of in situ microscale analysis using laser ablation (LA) over bulk sample analysis is to use the spatial context of different phases in the solid sample to disclose the processes that govern their chemical and isotopic compositions. However, there is a lack of in situ analytical routines to obtain a samples' stable isotope ratio together with its chemical composition. Here, we evaluate two novel analytical routines for the simultaneous determination of the chemical and Si stable isotope composition (δ 30 Si) on the micrometre scale in geological samples. In both routines, multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) is combined with femtosecond-LA, where stable isotope ratios are corrected for mass bias using standard-sample-bracketing with matrix-independent calibration. The first method is based on laser ablation split stream (LASS), where the laser aerosol is split and introduced simultaneously into both the MC-ICP-MS and a quadrupole ICP-MS. The second method is based on optical emission spectroscopy using direct observation of the MC-ICP-MS plasma (LA-MC-ICP-MS|OES). Both methods are evaluated using international geological reference materials. Accurate and precise Si isotope ratios were obtained with an uncertainty typically better than 0.23‰, 2SD, δ 30 Si. With both methods major element concentrations (e.g., Na, Al, Si, Mg, Ca) can be simultaneously determined. However, LASS-ICP-MS is superior over LA-MC-ICP-MS|OES, which is limited by its lower sensitivity. Moreover, LASS-ICP-MS offers trace element analysis down to the μg g −1 -range for more than 28 elements due to lower limits of detection, and with typical uncertainties better than 15%. For in situ

  19. Electrostatic interactions between polyglutamic acid and polylysine yields stable polyion complex micelles for deoxypodophyllotoxin delivery

    Directory of Open Access Journals (Sweden)

    Wang Y

    2017-10-01

    Full Text Available Yutong Wang,1–3,* Liping Huang,1,2,* Yan Shen,1,2,* Lidan Tang,1,2,4 Runing Sun,1,5 Di Shi,6 Thomas J Webster,6 Jiasheng Tu,1,2 Chunmeng Sun1,2 1Center for Research Development and Evaluation of Pharmaceutical Excipients and Generic Drugs, China Pharmaceutical University, 2State Key Laboratory of Natural Medicines, Department of Pharmaceutics, School of Pharmacy, China Pharmaceutical University, 3Department of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 4Changzhou Second People’s Hospital, Changzhou, 5School of Engineering, China Pharmaceutical University, Nanjing, People’s Republic of China; 6Department of Chemical Engineering, Northeastern University, Boston, MA, USA *These authors contributed equally to this work Abstract: To achieve enhanced physical stability of poly(ethylene glycol-poly(D,L-lactide polymeric micelles (PEG-PDLLA PMs, a mixture of methoxy PEG-PDLLA-polyglutamate (mPEG-PDLLA-PLG and mPEG-PDLLA-poly(L-lysine (mPEG-PDLLA-PLL copolymers was applied to self-assembled stable micelles with polyion-stabilized cores. Prior to micelle preparation, the synthetic copolymers were characterized by 1H-nuclear magnetic resonance (NMR and infrared spectroscopy (IR, and their molecular weights were calculated by 1H-NMR and gel permeation chromatography (GPC. Dialysis was used to prepare PMs with deoxypodophyllotoxin (DPT. Transmission electron microscopy (TEM images showed that DPT polyion complex micelles (DPT-PCMs were spherical, with uniform distribution and particle sizes of 36.3±0.8 nm. In addition, compared with nonpeptide-modified DPT-PMs, the stability of DPT-PCMs was significantly improved under various temperatures. In the meantime, the pH sensitivity induced by charged peptides allowed them to have a stronger antitumor effect and a pH-triggered release profile. As a result, the dynamic characteristic of DPT-PCM was retained, and high biocompatibility of DPT-PCM was observed in an in vivo study. These results

  20. Lys and Arg in UBI: A specific site for a stable Tc-99m complex?

    International Nuclear Information System (INIS)

    Melendez-Alafort, Laura; Ramirez, Flor de Maria; Ferro-Flores, Guillermina; Murphy, Consuelo Arteaga de; Pedraza-Lopez, Martha; Hnatowich, Donald J.

    2003-01-01

    The aim of this study was to help establish if ubiquicidin peptide 29-41 fragment (UBI) contains a specific site for 99m Tc labeling by a new direct method under alkaline conditions. Since this peptide does not have cysteine residues, it is possible that neighboring arginine and lysine in the peptide amino acid sequence (Thr-Gly-Arg-Ala-Lys-Arg-Arg-Met-Gln-Tyr-Asn-Arg-Arg) could be a specific coordination site to form a stable 99m Tc-UBI complex. Following direct labeling, the in vitro stability of 99m Tc-UBI was compared to UBI radiolabeled by one indirect method using HYNIC/tricine and HYNIC/tricine/EDDA. Radiochemical purity of 99m Tc-UBI averaged 97% compared to 88% for 99m Tc-HYNIC-UBI/tricine and 98% for 99m Tc-HYNIC-UBI/tricine/EDDA. Both 99m Tc-HYNIC-UBI (tricine or EDDA) and 99m Tc-UBI showed stability in human serum and solutions of cysteine. 99m Tc-UBI radiochemical purity 24 h after dilution in 0.9% NaCl was greater than 90% at pH 9 and greater than 95% at pH 6.5. Under one set of experimental conditions, in vitro binding to bacteria of 99m Tc-UBI was 35% and identical to that of 99m Tc-HYNIC-UBI/tricine and 99m Tc-HYNIC-UBI/tricine/EDDA at 32% and 31% respectively. The biodistribution of 99m Tc-UBI in mice showed a rapid renal clearance. To help identify the site(s) of 99m Tc binding following direct labeling, molecular mechanics and quantum-mechanical calculations were performed which showed that the amine groups of Arg 7 and Lys are the most probable site. The calculations show that these groups can form a square pyramid with two water molecules for the Tc cation (dxysp 3 ). It will be necessary to isolate and characterize the 99 Tc(V)(O)-UBI . (H 2 O) n complex to confirm these results

  1. Effects of arbuscular mycorrhizal fungi on gas exchange and stable isotope ratio of δ13C, δ15N of leymus chinensis plant

    International Nuclear Information System (INIS)

    Shi Weiqi; Wang Guoan; Li Xiaolin

    2008-01-01

    Leymus chinensis, one of dominant species in Inner Mongolia grassland, was selected to evaluate the effects of arbuscular mycorrhizal fungi (AMF) on plant gas change parameters and stable isotope ratio in pot culture. The plant was inoculated with two mycorrhizal fungi, Glomus intraradices and Glomus claroidum, and the uninoculated plant was used as the control check. On the 45th , 60th , 75th days after sowing, gas exchange parameters and stable isotope ratio were measured. The results showed that AM infection promoted phosphoms content, stomatal conductance and photosynthetic rate of Leymus chinensis, reduced host δ 15 N, however, it did not influence host intrinsic water using efficiency and δ 13 C. It was the growth time that significantly affected the gas exchange and stable isotope ratio of δ 13 C and δ 15 N. And the interaction of inoculation and growth time also influenced on the net photosynthetic rate, δ 13 C and δ 15 N of the host. Stomatal conductance and photosynthetic rate were always changed the same direction by arbuscular mycorrhizal fungi causing no significant difference between mycorrhizal and non-mycorrhizal plant. AMF absorbed nitrogen and accumulated δ 15 N, thus, it transformed less 15 N into the host, and as a result, the mycorrhizal plant had lower δ 15 N. Therefore, the results gave a new way and reference to know of the grass balance of carbon gain and water cost and the nitrogen cycle in grassland. (authors)

  2. Letter Report: Stable Hydrogen and Oxygen Isotope Analysis of B-Complex Perched Water Samples

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Brady D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Moran, James J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Nims, Megan K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Saunders, Danielle L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-04-13

    Fine-grained sediments associated with the Cold Creek Unit at Hanford have caused the formation of a perched water aquifer in the deep vadose zone at the B Complex area, which includes waste sites in the 200-DV-1 Operable Unit and the single-shell tank farms in Waste Management Area B-BX-BY. High levels of contaminants, such as uranium, technetium-99, and nitrate, make this aquifer a continuing source of contamination for the groundwater located a few meters below the perched zone. Analysis of deuterium (2H) and 18-oxygen (18O) of nine perched water samples from three different wells was performed. Samples represent time points from hydraulic tests performed on the perched aquifer using the three wells. The isotope analyses showed that the perched water had δ2H and δ18O ratios consistent with the regional meteoric water line, indicating that local precipitation events at the Hanford site likely account for recharge of the perched water aquifer. Data from the isotope analysis can be used along with pumping and recovery data to help understand the perched water dynamics related to aquifer size and hydraulic control of the aquifer in the future.

  3. Reproducibility over a 1-month period of 1H-MR spectroscopic imaging NAA/Cr ratios in clinically stable multiple sclerosis patients.

    Science.gov (United States)

    Mostert, J P; Blaauw, Y; Koch, M W; Kuiper, A J; Hoogduin, J M; De Keyser, J

    2008-08-01

    N-acetylaspartate/creatine (NAA/Cr) ratios, assessed with proton magnetic resonance spectroscopy, are increasingly used as a surrogate marker for axonal dysfunction and degeneration in multiple sclerosis (MS). The purpose of this study was to test short-time reproducibility of NAA/Cr ratios in patients with clinically stable MS. In 35 MS patients we analysed NAA/Cr ratios obtained with (1)H-MR spectroscopic imaging at the centrum semiovale either with lateral ventricles partially included (group 1; n=15) or more cranially with no ventricles included (group 2; n=20). To test short-term reproducibility of the NAA/Cr measurements, patients were scanned twice 4 weeks apart. We determined mean NAA/Cr and Cho/Cr ratios of 12 grey matter and 24 white matter voxels. Mean NAA/Cr ratios of both the white and grey matter did not change after 4 weeks. Overall 4-week reproducibility of the NAA/Cr ratio, expressed as coefficient of variation, was 4.8% for grey matter and 3.5% for white matter. Reproducibility of cranial scanning of the ventricles was slightly better than with cerebrospinal fluid included. Our study shows good short-term reproducibility of NAA/Cr ratio measurements in the centrum semiovale, which supports the reliability of this technique for longitudinal studies.

  4. Stable-carbon isotope ratios for sourcing the nerve-agent precursor methylphosphonic dichloride and its products.

    Science.gov (United States)

    Moran, James J; Fraga, Carlos G; Nims, Megan K

    2018-08-15

    The ability to connect a chemical threat agent to a specific batch of a synthetic precursor can provide a fingerprint to contribute to effective forensic investigations. Stable isotope analysis can leverage intrinsic, natural isotopic variability within the molecules of a threat agent to unlock embedded chemical fingerprints in the material. Methylphosphonic dichloride (DC) is a chemical precursor to the nerve agent sarin. DC is converted to methylphosphonic difluoride (DF) as part of the sarin synthesis process. We used a suite of commercially available DC stocks to both evaluate the potential for δ 13 C analysis to be used as a fingerprinting tool in sarin-related investigations and to develop sample preparation techniques (using chemical hydrolysis) that can simplify isotopic analysis of DC and its synthetic products. We demonstrate that natural isotopic variability in DC results in at least three distinct, isotope-resolved clusters within the thirteen stocks we analyzed. Isotopic variability in the carbon feedstock (i.e., methanol) used for DC synthesis is likely inherited by the DC samples we measured. We demonstrate that the hydrolysis of DC and DF to methylphosphonic acid (MPA) can be used as a preparative step for isotopic analysis because the reaction does not impart a significant isotopic fractionation. MPA is more chemically stable, less toxic, and easier to handle than DC or DF. Further, the hydrolysis method we demonstrated can be applied to a suite of other precursors or to sarin itself, thereby providing a potentially valuable forensic tool. Copyright © 2018. Published by Elsevier B.V.

  5. The movement ecology of the straw-colored fruit bat, Eidolon helvum, in sub-Saharan Africa assessed by stable isotope ratios.

    Directory of Open Access Journals (Sweden)

    Gonzalo Ossa

    Full Text Available Flying foxes (Pteropodidae are key seed dispersers on the African continent, yet their migratory behavior is largely unknown. Here, we studied the movement ecology of the straw-colored fruit bat, Eidolon helvum, and other fruit bats by analyzing stable isotope ratios in fur collected from museum specimens. In a triple-isotope approach based on samples of two ecologically similar non-migratory pteropodids, we first confirmed that a stable isotope approach is capable of delineating between geographically distinct locations in Sub-Saharan Africa. A discriminant function analysis assigned 84% of individuals correctly to their capture site. Further, we assessed how well hydrogen stable isotope ratios (δ(2H of fur keratin collected from non-migratory species (n = 191 individuals records variation in δ(2H of precipitation water in sub-Saharan Africa. Overall, we found positive, negative and no correlations within the six studied species. We then developed a reduced major axis regression equation based on individual data of non-migratory species to predict where potentially migratory E. helvum (n = 88 would come from based on their keratin δ(2H. Across non-migratory species, δ(2H of keratin and local water correlated positively. Based on the isoscape origin model, 22% of E. helvum were migratory, i.e. individuals had migrated over at least 250 km prior to their capture. Migratory individuals came from locations at a median distance of about 860 km from the collection site, four even from distances of at least 2,000 km. Ground-truthing of our isoscape origin model based on keratin δ(2H of extant E. helvum (n = 76 supported a high predictive power of assigning the provenance of African flying foxes. Our study highlights that stable isotope ratios can be used to explain the migratory behavior of flying foxes, even on the isotopically relatively homogenous African continent, and with material collected by museums many decades or more than a century ago.

  6. The movement ecology of the straw-colored fruit bat, Eidolon helvum, in sub-Saharan Africa assessed by stable isotope ratios.

    Science.gov (United States)

    Ossa, Gonzalo; Kramer-Schadt, Stephanie; Peel, Alison J; Scharf, Anne K; Voigt, Christian C

    2012-01-01

    Flying foxes (Pteropodidae) are key seed dispersers on the African continent, yet their migratory behavior is largely unknown. Here, we studied the movement ecology of the straw-colored fruit bat, Eidolon helvum, and other fruit bats by analyzing stable isotope ratios in fur collected from museum specimens. In a triple-isotope approach based on samples of two ecologically similar non-migratory pteropodids, we first confirmed that a stable isotope approach is capable of delineating between geographically distinct locations in Sub-Saharan Africa. A discriminant function analysis assigned 84% of individuals correctly to their capture site. Further, we assessed how well hydrogen stable isotope ratios (δ(2)H) of fur keratin collected from non-migratory species (n = 191 individuals) records variation in δ(2)H of precipitation water in sub-Saharan Africa. Overall, we found positive, negative and no correlations within the six studied species. We then developed a reduced major axis regression equation based on individual data of non-migratory species to predict where potentially migratory E. helvum (n = 88) would come from based on their keratin δ(2)H. Across non-migratory species, δ(2)H of keratin and local water correlated positively. Based on the isoscape origin model, 22% of E. helvum were migratory, i.e. individuals had migrated over at least 250 km prior to their capture. Migratory individuals came from locations at a median distance of about 860 km from the collection site, four even from distances of at least 2,000 km. Ground-truthing of our isoscape origin model based on keratin δ(2)H of extant E. helvum (n = 76) supported a high predictive power of assigning the provenance of African flying foxes. Our study highlights that stable isotope ratios can be used to explain the migratory behavior of flying foxes, even on the isotopically relatively homogenous African continent, and with material collected by museums many decades or more than a century ago.

  7. Seasonal dynamics of stable isotopes and element ratios in authigenic calcites during their precipitation and dissolution, Sacrower See (northeastern Germany

    Directory of Open Access Journals (Sweden)

    Bernd ZOLITSCHKA

    2009-08-01

    Full Text Available The seasonal evolution of chemical and physical water properties as well as particle fluxes was monitored in Sacrower See (northeastern Germany during two consecutive years (Oct 2003 - Oct 2005. Additonally, we measured δ18O and δ13C as well as Sr:Ca and Mg:Ca ratios of authigenic calcites that were collected in sequencing sediment traps in order to disentangle environmental and climatic factors controlling these parameters. In particular, our aim was to find out if element ratios and the isotopic composition of calcites reflect changes in water and air temperatures. Lake water is highly enriched in 18O (-1.3 to -2.5‰ VSMOW with an evaporative increase of 0.6‰ during summer. Values are 5-6‰ more positive than groundwater values and 4-5‰ more positive than long-term weighted annual means of precipitation. During spring and summer, high amounts of dissolved phosphate cause eutrophic conditions and calcite precipitation in isotopic disequilibrium. Measured values are depleted in 18O by 2 to 10‰ compared to calculated equilibrium values. Resuspension and partial dissolution of calcite in the water column contribute to this isotopic divergence in summer and autumn as δ18Oca and δ13C values increased in the hypolimnion during this time. Mg:Ca and Sr:Ca ratios are altered by dissolution as well. In the hypolimnion these ratios were higher than in the epilimnion. Another reason for the huge deviation between measured and theoretical δ18Oca values during summer is the occurrence of large amounts of Phacotus lenticularis in the carbonate fraction. High amounts of Phacotus lead to more negative δ18Oca and more positive δ13C values. Several characteristics of δ18Oca and δ13C are also reflected by Mg:Ca and Sr:Ca ratios and isotopic composition of oxygen and carbon were influenced by the onset and stability of stratification. Especially the earlier onset of stratification in 2005 caused higher sediment fluxes and more positive carbon and

  8. Carbon and nitrogen stable isotope ratios of pelagic zooplankton elucidate ecohydrographic features in the oligotrophic Red Sea

    KAUST Repository

    Kürten, Benjamin

    2015-11-10

    Although zooplankton occupy key roles in aquatic biogeochemical cycles, little is known about the pelagic food web and trophodynamics of zooplankton in the Red Sea. Natural abundance stable isotope analysis (SIA) of carbon (δ13C) and N (δ15N) is one approach to elucidating pelagic food web structures and diet assimilation Integrating the combined effects of ecological processes and hydrography, ecohydrographic features often translate into geographic patterns in δ13C and δ15N values at the base of food webs. This is due, for example, to divergent 15N abundances in source end-members (deep water sources: high δ15N, diazotrophs: low δ15N). Such patterns in the spatial distributions of stable isotope values were coined isoscapes. Empirical data of atmospheric, oceanographic, and biological processes, which drive the ecohydrographic gradients of the oligotrophic Red Sea, are under-explored and some rather anticipated than proven. Specifically, five processes underpin Red Sea gradients: a) monsoon-related intrusions of nutrient-rich Indian Ocean water; b) basin scale thermohaline circulation; c) mesoscale eddy activity that causes up-welling of deep water nutrients into the upper layer; d) the biological fixation of atmospheric nitrogen (N2) by diazotrophs; and e) the deposition of aerosol-derived N. This study assessed relationships between environmental samples (nutrients, chlorophyll a), oceanographic data (temperature, salinity, current velocity [ADCP]), particulate organic matter (POM), and net-phytoplankton, with the δ13C and δ15N values of zooplankton collected in spring 2012 from 16°28’ to 26°57’N along the central axis of the Red Sea. The δ15N of bulk POM and most zooplankton taxa increased from North (Duba) to South (Farasan). The potential contribution of deep water nutrient-fueled phytoplankton, POM, and diazotrophs varied among sites. Estimates suggested higher diazotroph contributions in the North, a greater contribution of POM in the South

  9. A complex symbol signal-to-noise ratio estimator and its performance

    Science.gov (United States)

    Feria, Y.

    1994-01-01

    This article presents an algorithm for estimating the signal-to-noise ratio (SNR) of signals that contain data on a downconverted suppressed carrier or the first harmonic of a square-wave subcarrier. This algorithm can be used to determine the performance of the full-spectrum combiner for the Galileo S-band (2.2- to 2.3-GHz) mission by measuring the input and output symbol SNR. A performance analysis of the algorithm shows that the estimator can estimate the complex symbol SNR using 10,000 symbols at a true symbol SNR of -5 dB with a mean of -4.9985 dB and a standard deviation of 0.2454 dB, and these analytical results are checked by simulations of 100 runs with a mean of -5.06 dB and a standard deviation of 0.2506 dB.

  10. Combined Stable Carbon Isotope and C/N Ratios as Indicators of Source and Fate of Organic Matter in the Bang Pa kong River Estuary, Thailand

    International Nuclear Information System (INIS)

    Boonphakdee, Thanomsak; Kasai, Akihide; Fujiwara, Tateki; Sawangwong, Pichan; Cheevaporn, Voravit

    2007-08-01

    Full text: Stable carbon isotopes and C/N ratios of particulate organic matter (POM) in suspended solids and surficial sediment were used to define the spatial and temporal variability in an anthropogenic tropical river estuary, the Bang Pa kong River Estuary. Samples were taken along salinity gradients during the four different river discharges in the beginning, high river discharge and at the end of the wet season, and low river discharge during the dry season. The values of [C/N]a ratio and d13C in the river estuary revealed significant differences from those of the offshore station. Conservative behaviors of [C/N]a and d13C in the estuary during the wet season indicated major contribution of terrigenous C3 plants derived OM. By contrast, during the dry season, marine input mainly dominated OM contribution with an evidence of anthropogenic input to the estuary. These compositions of the bulk sedimentary OM were dominated by paddy rice soils and marine derived OM during the wet and dry seasons, respectively. These results show that the combined stable carbon isotopes and C/N ratios can be used to identify the source and fate of OM even in a river estuary. This tool will be useful to achieve sustainable management in coastal zone

  11. Distribution of trace elements in organs of six species of cetaceans from the Ligurian Sea (Mediterranean), and the relationship with stable carbon and nitrogen ratios

    Energy Technology Data Exchange (ETDEWEB)

    Capelli, R. [Dipartimento di Chimica e Tecnologie Farmaceutiche ed Alimentari - Universita degli Studi di Genova - Via Brigata Salerno, 13 I-16147 Genova (Italy); Das, K. [MARE center, Laboratory for Oceanology, University of Liege, B6 Sart-Tilman, B-4000 Liege (Belgium); Pellegrini, R. De; Drava, G. [Dipartimento di Chimica e Tecnologie Farmaceutiche ed Alimentari - Universita degli Studi di Genova - Via Brigata Salerno, 13 I-16147 Genova (Italy); Lepoint, G. [MARE center, Laboratory for Oceanology, University of Liege, B6 Sart-Tilman, B-4000 Liege (Belgium); Miglio, C. [Dipartimento di Chimica e Tecnologie Farmaceutiche ed Alimentari - Universita degli Studi di Genova - Via Brigata Salerno, 13 I-16147 Genova (Italy); Minganti, V. [Dipartimento di Chimica e Tecnologie Farmaceutiche ed Alimentari - Universita degli Studi di Genova - Via Brigata Salerno, 13 I-16147 Genova (Italy)], E-mail: minganti@dictfa.unige.it; Poggi, R. [Museo Civico di Storia Naturale ' Giacomo Doria' - Via Brigata Liguria, 9 I-16121 Genova (Italy)

    2008-02-15

    Mercury (total and organic), cadmium, lead, copper, iron, manganese, selenium and zinc concentrations were measured in different organs of 6 different cetacean species stranded in an area of extraordinary ecological interest (Cetaceans' Sanctuary of the Mediterranean Sea) along the coast of the Ligurian Sea (North-West Mediterranean). Stable-isotopes ratios of carbon ({sup 13}C/{sup 12}C) and nitrogen ({sup 15}N/{sup 14}N) were also measured in the muscle. A significant relationship exists between {sup 15}N/{sup 14}N, mercury concentration and the trophic level. The distribution of essential and non-essential trace elements was studied on several organs, and a significant relationship between selenium and mercury, with a molar ratio close to 1, was found in the cetaceans' kidney, liver and spleen, regardless of their species. High selenium concentrations are generally associated with a low organic to total mercury ratio. While narrow ranges of concentrations were observed for essential elements in most organs, mercury and selenium concentrations are characterised by a wide range of variation. Bio-accumulation and bio-amplification processes in cetaceans can be better understood by comparing trace element concentrations with the stable-isotopes data.

  12. Formation of polyelectrolyte complexes with diethylaminoethyl dextran: charge ratio and molar mass effect.

    Science.gov (United States)

    Le Cerf, Didier; Pepin, Anne Sophie; Niang, Pape Momar; Cristea, Mariana; Karakasyan-Dia, Carole; Picton, Luc

    2014-11-26

    The formation of polyelectrolyte complexes (PECs) between carboxymethyl pullulan and DEAE Dextran, was investigated, in dilute solution, with emphasis on the effect of charge density (molar ratio or pH) and molar masses. Electrophoretic mobility measurements have evidenced that insoluble PECs (neutral electrophoretic mobility) occurs for charge ratio between 0.6 (excess of polycation) and 1 (stoichiometry usual value) according to the pH. This atypical result is explained by the inaccessibility of some permanent cationic charge when screened by pH dependant cationic ones (due to the Hoffman alkylation). Isothermal titration calorimetry (ITC) indicates an endothermic formation of PEC with a binding constant around 10(5) L mol(-1). Finally asymmetrical flow field flow fractionation coupled on line with static multi angle light scattering (AF4/MALS) evidences soluble PECs with very large average molar masses and size around 100 nm, in agreement with scrambled eggs multi-association between various polyelectrolyte chains. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Anion-π aromatic neutral tweezers complexes: are they stable in polar solvents?

    Science.gov (United States)

    Sánchez-Lozano, Marta; Otero, Nicolás; Hermida-Ramón, Jose M; Estévez, Carlos M; Mandado, Marcos

    2011-03-17

    The impact of the solvent environment on the stabilization of the complexes formed by fluorine (T-F) and cyanide (T-CN) substituted tweezers with halide anions has been investigated theoretically. The study was carried out using computational methodologies based on density functional theory (DFT) and symmetry adapted perturbation theory (SAPT). Interaction energies were obtained at the M05-2X/6-31+G* level. The obtained results show a large stability of the complexes in solvents with large dielectric constant and prove the suitability of these molecular tweezers as potential hosts for anion recognition in solution. A detailed analysis of the effects of the solvent on the electron withdrawing ability of the substituents and its influence on the complex stability has been performed. In particular, the interaction energy in solution was split up into intermonomer and solvent-complex terms. In turn, the intermonomer interaction energy was partitioned into electrostatic, exchange, and polarization terms. Polar resonance structures in T-CN complexes are favored by polar solvents, giving rise to a stabilization of the intermonomer interaction, the opposite is found for T-F complexes. The solvent-complex energy increases with the polarity of the solvent in T-CN complexes, nonetheless the energy reaches a maximum and then decreases slowly in T-F complexes. An electron density analysis was also performed before and after complexation, providing an explanation to the trends followed by the interaction energies and their different components in solution.

  14. Archaeal orthologs of Cdc45 and GINS form a stable complex that stimulates the helicase activity of MCM.

    Science.gov (United States)

    Xu, Yuli; Gristwood, Tamzin; Hodgson, Ben; Trinidad, Jonathan C; Albers, Sonja-Verena; Bell, Stephen D

    2016-11-22

    The regulated recruitment of Cdc45 and GINS is key to activating the eukaryotic MCM(2-7) replicative helicase. We demonstrate that the homohexameric archaeal MCM helicase associates with orthologs of GINS and Cdc45 in vivo and in vitro. Association of these factors with MCM robustly stimulates the MCM helicase activity. In contrast to the situation in eukaryotes, archaeal Cdc45 and GINS form an extremely stable complex before binding MCM. Further, the archaeal GINS•Cdc45 complex contains two copies of Cdc45. Our analyses give insight into the function and evolution of the conserved core of the archaeal/eukaryotic replisome.

  15. Correlation between the synthetic origin of methamphetamine samples and their {sup 15}N and {sup 13}C stable isotope ratios

    Energy Technology Data Exchange (ETDEWEB)

    Billault, Isabelle [Laboratoire d' Analyse Isotopique et Electrochimique de Metabolismes, CNRS UMR6006, University of Nantes, BP 92208, 44322 Nantes (France)]. E-mail: Isabelle.Billault@univ-nantes.fr; Courant, Frederique [Laboratoire d' Analyse Isotopique et Electrochimique de Metabolismes, CNRS UMR6006, University of Nantes, BP 92208, 44322 Nantes (France); Pasquereau, Leo [Laboratoire d' Analyse Isotopique et Electrochimique de Metabolismes, CNRS UMR6006, University of Nantes, BP 92208, 44322 Nantes (France); Derrien, Solene [Laboratoire d' Analyse Isotopique et Electrochimique de Metabolismes, CNRS UMR6006, University of Nantes, BP 92208, 44322 Nantes (France); Robins, Richard J. [Laboratoire d' Analyse Isotopique et Electrochimique de Metabolismes, CNRS UMR6006, University of Nantes, BP 92208, 44322 Nantes (France); Naulet, Norbert [Laboratoire d' Analyse Isotopique et Electrochimique de Metabolismes, CNRS UMR6006, University of Nantes, BP 92208, 44322 Nantes (France)

    2007-06-12

    The active ingredient of ecstasy, N-methyl-3,4-methyldioxyphenylisopropylamine (MDMA) can be manufactured by a number of easy routes from simple precursors. We have synthesised 45 samples of MDMA following the five most common routes using N-precursors from 12 different origins and three different precursors for the aromatic moiety. The {sup 13}C and {sup 15}N contents of both the precursors and the MDMA samples derived therefrom were measured by isotope ratio mass spectrometry coupled to an elemental analyser (EA-IRMS). We show that within-pathway correlation between the {sup 15}N content of the precursor and that of the derived MDMA can be strong but that no general pattern of correlation can be defined. Rather, it is evident that the {delta} {sup 15}N values of MDMA are strongly influenced by a combination of the {delta} {sup 15}N values of the source of nitrogen used, the route by which the MDMA is synthesised, and the experimental conditions employed. Multivariate analysis (PCA) based on the {delta} {sup 15}N values of the synthetic MDMA and of the {delta} {sup 15}N and {delta} {sup 13}C values of the N-precursors leads to good discrimination between the majority of the reaction conditions tested.

  16. Correlation between the synthetic origin of methamphetamine samples and their 15N and 13C stable isotope ratios

    International Nuclear Information System (INIS)

    Billault, Isabelle; Courant, Frederique; Pasquereau, Leo; Derrien, Solene; Robins, Richard J.; Naulet, Norbert

    2007-01-01

    The active ingredient of ecstasy, N-methyl-3,4-methyldioxyphenylisopropylamine (MDMA) can be manufactured by a number of easy routes from simple precursors. We have synthesised 45 samples of MDMA following the five most common routes using N-precursors from 12 different origins and three different precursors for the aromatic moiety. The 13 C and 15 N contents of both the precursors and the MDMA samples derived therefrom were measured by isotope ratio mass spectrometry coupled to an elemental analyser (EA-IRMS). We show that within-pathway correlation between the 15 N content of the precursor and that of the derived MDMA can be strong but that no general pattern of correlation can be defined. Rather, it is evident that the δ 15 N values of MDMA are strongly influenced by a combination of the δ 15 N values of the source of nitrogen used, the route by which the MDMA is synthesised, and the experimental conditions employed. Multivariate analysis (PCA) based on the δ 15 N values of the synthetic MDMA and of the δ 15 N and δ 13 C values of the N-precursors leads to good discrimination between the majority of the reaction conditions tested

  17. Authenticity testing of environment-friendly Korean rice (Oryza sativa L.) using carbon and nitrogen stable isotope ratio analysis.

    Science.gov (United States)

    Chung, Ill-Min; Park, Sung-Kyu; Lee, Kyoung-Jin; An, Min-Jeong; Lee, Ji-Hee; Oh, Yong-Taek; Kim, Seung-Hyun

    2017-11-01

    The increasing demand for organic foods creates, in turn, a pressing need for the development of more accurate tools for the authentication of organic food in order to ensure both fair trade and food safety. This study examines the feasibility of δ 13 C and δ 15 N analyses as potential tools for authentication of environment-friendly rice sold in Korea. δ 13 C and δ 15 N examination in different rice grains showed that environment-friendly rice can be successfully distinguished from conventional rice. No multi-residue pesticides were detected in the examined rice samples, including conventional rice. This study demonstrates the complementary feasibility of δ 13 C and δ 15 N analyses for the authentication of environment-friendly rice sold in Korea in cases where pesticide residue analysis alone is insufficient for discrimination of organic and conventional rice. In future, complementary analyses including compound-specific isotope ratio analysis might be employed for improving the reliability of organic authentication. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Highly Manufacturable Deep (Sub-Millimeter) Etching Enabled High Aspect Ratio Complex Geometry Lego-Like Silicon Electronics

    KAUST Repository

    Ghoneim, Mohamed T.; Hussain, Muhammad Mustafa

    2017-01-01

    A highly manufacturable deep reactive ion etching based process involving a hybrid soft/hard mask process technology shows high aspect ratio complex geometry Lego-like silicon electronics formation enabling free-form (physically flexible

  19. Value of digit ratio 2D:4D, a biomarker of prenatal hormone exposure, is stable across the menstrual cycle.

    Science.gov (United States)

    Klimek, Magdalena; Marcinkowska, Urszula M; Jasienska, Grazyna

    2017-07-01

    Digit ratio (2D:4D) is used as a marker of prenatal hormone exposure and, consequently, as a predictor of many characteristics throughout a woman's lifespan. A previous study has suggested that values of 2D:4D vary across menstrual cycles and further questioned the reliability of a single measurement of 2D:4D among cycling women, while another study failed to confirm these results. However, these studies estimated the timing of cycle phases based on a date of menstruation reported by participants and also had small sample sizes. For our study, we evaluated potential changes in 2D:4D values across a menstrual cycle in a group of women among whom the phases of the menstrual cycle were determined by hormonal (luteinizing hormone based) ovulation tests. We studied 32 naturally cycling women aged 22-37 from rural Poland. Lengths of second and fourth digits were measured based on scans of both hands taken three times (i.e. in the follicular phase, peri-ovulatory phase and luteal phase of the cycle) for each participant. No differences in 2D:4D value across the menstrual cycle were detected either when right-hand, left-hand, and mean 2D:4D for both hands were analysed, nor when difference in the 2D:4D value between hands (D left-right ) was evaluated. We documented that 2D:4D is independent of the phase of the menstrual cycle and these findings suggest that among naturally cycling women, a value of 2D:4D can be reliably obtained from measurements taken during any day of the menstrual cycle. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Carbon and nitrogen stable isotope ratios analysis of food sources for Chironomus acerbiphilus larvae (Diptera Chironomidae) in strongly acidic lake Katanuma

    Energy Technology Data Exchange (ETDEWEB)

    Doi, Hideyuki [Tohoku Univ., Sendai (Japan). Graduate School of Science; Kikuchi, Eisuke; Shikano, Shuichi

    2001-12-01

    The food sources for Chironomus acerbiphilus larvae (Diptera Chironomidae) were analyzed using carbon and nitrogen stable isotope ratios in Lake Katanuma. Lake Katanuma is a volcanic and strongly acidic lake (average pH 2.2). In Lake Katanuma, potential sources of diets for the chironomid larvae are limited including a benthic diatom (Pinnularia braunii), a phytoplankton (Chlamydomonas acidophila), sulfate oxidizing bacteria, and vascular plants supplied from vegetation surrounding the lake. Based on the average carbon and nitrogen isotope ratios among these potential sources and sediment, benthic diatoms were considered to be most probable food source of the chironomid larvae. {delta}{sup 13}C values of the chironomid were significantly different among seasons and habitat depths, suggesting that diet of C. acerbiphilus changed seasonally and with habitat depth. (author)

  1. Carbon and nitrogen stable isotope ratios analysis of food sources for Chironomus acerbiphilus larvae (Diptera Chironomidae) in strongly acidic lake Katanuma

    International Nuclear Information System (INIS)

    Doi, Hideyuki; Kikuchi, Eisuke; Shikano, Shuichi

    2001-01-01

    The food sources for Chironomus acerbiphilus larvae (Diptera Chironomidae) were analyzed using carbon and nitrogen stable isotope ratios in Lake Katanuma. Lake Katanuma is a volcanic and strongly acidic lake (average pH 2.2). In Lake Katanuma, potential sources of diets for the chironomid larvae are limited including a benthic diatom (Pinnularia braunii), a phytoplankton (Chlamydomonas acidophila), sulfate oxidizing bacteria, and vascular plants supplied from vegetation surrounding the lake. Based on the average carbon and nitrogen isotope ratios among these potential sources and sediment, benthic diatoms were considered to be most probable food source of the chironomid larvae. δ 13 C values of the chironomid were significantly different among seasons and habitat depths, suggesting that diet of C. acerbiphilus changed seasonally and with habitat depth. (author)

  2. An assessment of the information content of likelihood ratios derived from complex mixtures.

    Science.gov (United States)

    Marsden, Clare D; Rudin, Norah; Inman, Keith; Lohmueller, Kirk E

    2016-05-01

    With the increasing sensitivity of DNA typing methodologies, as well as increasing awareness by law enforcement of the perceived capabilities of DNA typing, complex mixtures consisting of DNA from two or more contributors are increasingly being encountered. However, insufficient research has been conducted to characterize the ability to distinguish a true contributor (TC) from a known non-contributor (KNC) in these complex samples, and under what specific conditions. In order to investigate this question, sets of six 15-locus Caucasian genotype profiles were simulated and used to create mixtures containing 2-5 contributors. Likelihood ratios were computed for various situations, including varying numbers of contributors and unknowns in the evidence profile, as well as comparisons of the evidence profile to TCs and KNCs. This work was intended to illustrate the best-case scenario, in which all alleles from the TC were detected in the simulated evidence samples. Therefore the possibility of drop-out was not modeled in this study. The computer program DNAMIX was then used to compute LRs comparing the evidence profile to TCs and KNCs. This resulted in 140,000 LRs for each of the two scenarios. These complex mixture simulations show that, even when all alleles are detected (i.e. no drop-out), TCs can generate LRs less than 1 across a 15-locus profile. However, this outcome was rare, 7 of 140,000 replicates (0.005%), and associated only with mixtures comprising 5 contributors in which the numerator hypothesis includes one or more unknown contributors. For KNCs, LRs were found to be greater than 1 in a small number of replicates (75 of 140,000 replicates, or 0.05%). These replicates were limited to 4 and 5 person mixtures with 1 or more unknowns in the numerator. Only 5 of these 75 replicates (0.004%) yielded an LR greater than 1,000. Thus, overall, these results imply that the weight of evidence that can be derived from complex mixtures containing up to 5 contributors

  3. Pseudosatellite technologies based on the use of functionally stable complexes of remote-piloted aircrafts

    Science.gov (United States)

    Mashkov, O. A.; Samborskiy, I. I.

    2009-10-01

    A bundle of papers dealing with functionally stable systems requires the necessity of analyzing of obtained results and their understanding in a general context of cybernetic's development and applications. Description of this field of science, main results and perspectives of the new theory of functionally stability of dynamical systems concerning the problem of remote-piloted aircrafts engineering using pseudosatellite technologies are proposed in the paper.

  4. Extremely stable soluble high molecular mass multi-protein complex with DNase activity in human placental tissue.

    Directory of Open Access Journals (Sweden)

    Evgeniya E Burkova

    Full Text Available Human placenta is an organ which protects, feeds, and regulates the grooving of the embryo. Therefore, identification and characterization of placental components including proteins and their multi-protein complexes is an important step to understanding the placenta function. We have obtained and analyzed for the first time an extremely stable multi-protein complex (SPC, ∼ 1000 kDa from the soluble fraction of three human placentas. By gel filtration on Sepharose-4B, the SPC was well separated from other proteins of the placenta extract. Light scattering measurements and gel filtration showed that the SPC is stable in the presence of NaCl, MgCl2, acetonitrile, guanidinium chloride, and Triton in high concentrations, but dissociates efficiently in the presence of 8 M urea, 50 mM EDTA, and 0.5 M NaCl. Such a stable complex is unlikely to be a casual associate of different proteins. According to SDS-PAGE and MALDI mass spectrometry data, this complex contains many major glycosylated proteins with low and moderate molecular masses (MMs 4-14 kDa and several moderately abundant (79.3, 68.5, 52.8, and 27.2 kDa as well as minor proteins with higher MMs. The SPC treatment with dithiothreitol led to a disappearance of some protein bands and revealed proteins with lower MMs. The SPCs from three placentas efficiently hydrolyzed plasmid supercoiled DNA with comparable rates and possess at least two DNA-binding sites with different affinities for a 12-mer oligonucleotide. Progress in study of placental protein complexes can promote understanding of their biological functions.

  5. Meta-analysis of amino acid stable nitrogen isotope ratios for estimating trophic position in marine organisms.

    Science.gov (United States)

    Nielsen, Jens M; Popp, Brian N; Winder, Monika

    2015-07-01

    Estimating trophic structures is a common approach used to retrieve information regarding energy pathways, predation, and competition in complex ecosystems. The application of amino acid (AA) compound-specific nitrogen (N) isotope analysis (CSIA) is a relatively new method used to estimate trophic position (TP) and feeding relationships in diverse organisms. Here, we conducted the first meta-analysis of δ(15)N AA values from measurements of 359 marine species covering four trophic levels, and compared TP estimates from AA-CSIA to literature values derived from food items, gut or stomach content analysis. We tested whether the AA trophic enrichment factor (TEF), or the (15)N enrichment among different individual AAs is constant across trophic levels and whether inclusion of δ(15)N values from multiple AAs improves TP estimation. For the TEF of glutamic acid relative to phenylalanine (Phe) we found an average value of 6.6‰ across all taxa, which is significantly lower than the commonly applied 7.6‰. We found that organism feeding ecology influences TEF values of several trophic AAs relative to Phe, with significantly higher TEF values for herbivores compared to omnivores and carnivores, while TEF values were also significantly lower for animals excreting urea compared to ammonium. Based on the comparison of multiple model structures using the metadata of δ(15)N AA values we show that increasing the number of AAs in principle improves precision in TP estimation. This meta-analysis clarifies the advantages and limitations of using individual δ(15)N AA values as tools in trophic ecology and provides a guideline for the future application of AA-CSIA to food web studies.

  6. A study of radionuclides, metals and stable lead isotope ratios in sediments and soils in the vicinity of natural U-mineralisation areas in the Northern Territory

    International Nuclear Information System (INIS)

    Frostick, A.; Bollhoefer, A.; Parry, D.

    2011-01-01

    Australian guidelines recommend that tailings materials from uranium (U) mining and milling be contained without any detrimental impact on the environment for at least 1000 years. Natural analogue sites are being investigated to determine if they can provide data on the rates of natural erosion processes which occur over these timescales, for input into predictive geomorphic computer models. This paper presents radionuclide, metal and stable lead (Pb) isotope data from sediment cores and surface soils in the vicinity of two mineralised areas in the Alligator Rivers Region. Surface scrapes from the natural Anomaly no. 2, south of the Ranger mineral lease, exhibit radiogenic 206 Pb/ 207 Pb and 208 Pb/ 207 Pb ratios, and elevated U and metal concentrations typical for a near surface U anomaly. In contrast, samples taken from the Koongarra mineral lease (KML) show radionuclide activity and metal concentrations similar to natural areas elsewhere in the Alligator Rivers Region and Pb isotope ratios are closer to present day average crustal ratios (PDAC), as the orebodies at KML are covered by surficial sand. A sediment core collected from Anbangbang Billabong, downstream of KML, exhibits small variations in Pb isotope ratios that indicate that approximately 1% of the upper sediments in the sediment core may be derived from material originating from the U anomaly at Koongarra.

  7. A study of radionuclides, metals and stable lead isotope ratios in sediments and soils in the vicinity of natural U-mineralisation areas in the Northern Territory

    Energy Technology Data Exchange (ETDEWEB)

    Frostick, A., E-mail: Alison.Frostick@cdu.edu.au [Charles Darwin University, School of Environment and Life Sciences, Darwin NT 0909 (Australia); ERISS, GPO Box 461, Darwin NT 0801 (Australia); Bollhoefer, A. [ERISS, GPO Box 461, Darwin NT 0801 (Australia); Parry, D. [AIMS, PO Box 41775, Casuarina NT 0811 (Australia)

    2011-10-15

    Australian guidelines recommend that tailings materials from uranium (U) mining and milling be contained without any detrimental impact on the environment for at least 1000 years. Natural analogue sites are being investigated to determine if they can provide data on the rates of natural erosion processes which occur over these timescales, for input into predictive geomorphic computer models. This paper presents radionuclide, metal and stable lead (Pb) isotope data from sediment cores and surface soils in the vicinity of two mineralised areas in the Alligator Rivers Region. Surface scrapes from the natural Anomaly no. 2, south of the Ranger mineral lease, exhibit radiogenic {sup 206}Pb/{sup 207}Pb and {sup 208}Pb/{sup 207}Pb ratios, and elevated U and metal concentrations typical for a near surface U anomaly. In contrast, samples taken from the Koongarra mineral lease (KML) show radionuclide activity and metal concentrations similar to natural areas elsewhere in the Alligator Rivers Region and Pb isotope ratios are closer to present day average crustal ratios (PDAC), as the orebodies at KML are covered by surficial sand. A sediment core collected from Anbangbang Billabong, downstream of KML, exhibits small variations in Pb isotope ratios that indicate that approximately 1% of the upper sediments in the sediment core may be derived from material originating from the U anomaly at Koongarra.

  8. The existence of a stable noncollinear phase in a Heisenberg model with complex structure

    Energy Technology Data Exchange (ETDEWEB)

    Shopova, Diana V.; Boyadjiev, Todor L

    2003-05-19

    We have analyzed the properties of a noncollinear magnetic phase obtained in the mean-field analysis of the model of two coupled Heisenberg subsystems. The domain of its existence and stability is narrow and depends on the ratio between the averaged over nearest neighbours microscopic exchange parameters.

  9. Radiation-induced dissociation of stable DNA-protein complexes in Erlich ascites carcinoma cells

    International Nuclear Information System (INIS)

    Juhasz, P.P.; Sirota, N.P.; Gaziev, A.I.

    1982-01-01

    DNA of Ehrlich ascites carcinoma cells prepared under conditions that were highly denaturing for proteins but not for DNA, contained a group of nonhistone residual proteins. The amount of these proteins increased during DNA replication. The DNA-protein complex observed was sensitive to proteolytic enzymes and/or SH-reagents. γ-irradiation cells with moderate doses leads to a decrease in the amount of DNA-protein complexes. High-dose gamma-irradiation produces enhanced linking of chromosomal proteins with DNA. (author)

  10. A novel stable 3D luminescent uranyl complex for highly efficient and sensitive recognition of Ru3+ and biomolecules

    Science.gov (United States)

    Tian, Hong-Hong; Chen, Liang-Ting; Zhang, Rong-Lan; Zhao, Jian-She; Liu, Chi-Yang; Weng, Ng Seik

    2018-02-01

    A novel highly stable 3D luminescent uranyl coordination polymer, namely {[UO2(L)]·DMA}n (1), was assembled with uranyl salt and a glycine-derivative ligand [6-(carboxymethyl-amino)-4-oxo-4,5-dihydro-[1,3,5]triazin-2-ylamino]-acetic acid (H2L) under solvothermal reaction. Besides, It was found that complex 1 possesses excellent luminescent properties, particularly the efficient selectivity and sensitivity in the recognition of Ru3+, biomacromolecule bovine serum albumin (BSA), biological small molecules dopamine (DA), ascorbic acid (AA) and uric acid (UA) in the water solution based on a "turn-off" mechanism. Accordingly, the luminescent explorations also demonstrated that complex 1 could be acted as an efficient luminescent probe with high quenching efficiency and low detection limit for selectively detecting Ru3+ and biomolecules (DA, AA, UA and BSA). It was noted that the framework structure of complex 1 still remains highly stable after quenching, which was verified by powder X-ray diffraction (PXRD).

  11. Stable lead isotope ratios and metals in freshwater mussels from a uranium mining environment in Australia’s wet-dry tropics

    International Nuclear Information System (INIS)

    Bollhöfer, Andreas

    2012-01-01

    Highlights: ► Lead isotope ratios in mussels from Magela more uranogenic than from Sandy catchment. ► Additional input of Broken Hill type lead further downstream of mine site. ► Lead isotope ratios in mussels ideal for source apportionment of lead into waterways. - Abstract: Concentrations of Fe, Mn, Cu, Zn, U and Pb, and stable Pb isotopes 206 Pb, 207 Pb and 208 Pb were measured via inductively coupled plasma mass spectrometry in sediments, water and freshwater mussels (Velesunio angasi) from two catchments in the Alligator Rivers Region, Australia. Sediment U and Pb concentrations were higher in Magela Creek downstream than upstream of the Ranger U mine due to the mineralised nature of the catchment and potential local input of sediment from the mine site. Water metal concentrations were highest in Georgetown Creek, which is a tributary of Magela Creek and part drains the Ranger mine site, but there was little difference in concentrations between the Magela Creek upstream and downstream sites. Metal concentrations in mussels collected immediately upstream and downstream of the mine site also showed little difference, whereas Pb isotope ratios displayed a very distinct pattern. The 206 Pb/ 207 Pb and 208 Pb/ 207 Pb isotope ratios were more uranogenic downstream than upstream of the site and also more uranogenic than ratios measured in Sandy Billabong, a reference billabong in a catchment not influenced by U mineralisation. Isotope ratios were also more uranogenic in younger mussels, potentially due to the increasing footprint of the mine site over the past decade. The most uranogenic ratios were found in mussels from Georgetown Creek and at a site approximately 2 km downstream. At Mudginberri Billabong, approximately 12 km downstream of the Ranger mine, the relative contribution of uranogenic Pb to the total Pb concentration in mussels was small and overwhelmed by the input of industrial Pb with a Broken Hill type Pb signature. Whereas metal uptake by and

  12. Formation of stable nanoparticles via electrostatic complexation between sodium caseinate and gum arabic.

    Science.gov (United States)

    Ye, Aiqian; Flanagan, John; Singh, Harjinder

    2006-06-05

    The formation of electrostatic complexes between sodium caseinate and gum arabic (GA) was studied as a function of pH (2.0-7.0), using slow acidification in situ with glucono-delta-lactone (GDL) or titration with HCl. The colloidal behavior of the complexes under specific conditions was investigated using absorbance measurements (at 515 or 810 nm) and dynamic light scattering (DLS). In contrast to the sudden increase in absorbance and subsequent precipitation of sodium caseinate solutions at pH sodium caseinate and GA increased to a level that was dependent on GA concentration at pH 5.4 (pH(c)). The absorbance values remained constant with further decreases in pH until a sudden increase in absorbance was observed (at pH(phi)). The pH(phi) was also dependent upon the GA concentration. Dynamic light scattering (DLS) data showed that the sizes of the particles formed by the complexation of sodium caseinate and GA between pH(c) and pH(phi) were between 100 and 150 nm and these nanoparticles were visualized using negative staining transmission electron microscopy (TEM). Below pH(phi), the nanoparticles associated to form larger particles, causing phase separation. zeta-Potential measurements of the nanoparticles and chemical analysis after phase separation showed that phase separation was a consequence of charge neutralization. The formation of complexes between sodium caseinate and GA was inhibited at high ionic strength (>50 mM NaCl). It is postulated that the structure of the nanoparticles comprises an aggregated caseinate core, protected from further aggregation by steric repulsion of one, or more, electrostatically attached GA molecules. Copyright 2005 Wiley Periodicals, Inc.

  13. Estimation of different source contributions to sediment organic matter in an agricultural-forested watershed using end member mixing analyses based on stable isotope ratios and fluorescence spectroscopy.

    Science.gov (United States)

    Derrien, Morgane; Kim, Min-Seob; Ock, Giyoung; Hong, Seongjin; Cho, Jinwoo; Shin, Kyung-Hoon; Hur, Jin

    2018-03-15

    The two popular source tracing tools of stable isotope ratios (δ 13 C and δ 15 N) and fluorescence spectroscopy were used to estimate the relative source contributions to sediment organic matter (SeOM) at five different river sites in an agricultural-forested watershed (Soyang Lake watershed), and their capabilities for the source assignment were compared. Bulk sediments were used for the stable isotopes, while alkaline extractable organic matter (AEOM) from sediments was used to obtain fluorescent indices for SeOM. Several source discrimination indices were fully compiled for a range of the SeOM sources distributed in the catchments of the watershed, which included soils, forest leaves, crop (C3 and C4) and riparian plants, periphyton, and organic fertilizers. The relative source contributions to the river sediment samples were estimated via end member mixing analysis (EMMA) based on several selected discrimination indices. The EMMA based on the isotopes demonstrated that all sediments were characterized by a medium to a high contribution of periphyton ranging from ~30% to 70% except for one site heavily affected by forest and agricultural fields with relatively high contributions of terrestrial materials. The EMMA based on fluorescence parameters, however, did not show similar results with low contributions from forest leaf and periphyton. The characteristics of the studied watershed were more consistent with the source contributions determined by the isotope ratios. The discrepancy in the EMMA capability for source assignments between the two analytical tools can be explained by the limited analytical window of fluorescence spectroscopy for non-fluorescent dissolved organic matter (FDOM) and the inability of AEOM to represent original bulk particulate organic matter (POM). Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Feeding ecology and phylogenetic structure of a complex neotropical termite assemblage, revealed by nitrogen stable isotope ratios

    Czech Academy of Sciences Publication Activity Database

    Bourguignon, T.; Šobotník, Jan; Lepoint, G.; Martin, J. M.; Hardy, O. J.; Dejean, A.; Roisin, Y.

    2011-01-01

    Roč. 36, č. 2 (2011), s. 261-269 ISSN 0307-6946 Institutional research plan: CEZ:AV0Z40550506 Keywords : diet diversity * feeding groups * Isoptera * phylogenetic autocorrelation Subject RIV: CC - Organic Chemistry Impact factor: 1.995, year: 2011

  15. Rapid presumptive identification of the Mycobacterium tuberculosis-bovis complex by radiometric determination of heat stable urease

    International Nuclear Information System (INIS)

    Gandy, J.H.; Pruden, E.L.; Cox, F.R.

    1983-01-01

    Simple and rapid Bactec methodologies for the determination of neat (unaltered) and heat stable urease activity of mycobacteria are presented. Clinical isolates (63) and stock cultures (32)--consisting of: M. tuberculosis (19), M. bovis (5), M. kansasii (15), M. marinum (4), M. simiae (3), M. scrofulaceum (16), M. gordonae (6), M. szulgai (6), M. flavescens (1), M. gastri (1), M. intracellulare (6), M. fortuitum-chelonei complex (12), and M. smegmatis (1)--were tested for neat urease activity by Bactec radiometry. Mycobacterial isolates (50-100 mg wet weight) were incubated at 35 degrees C for 30 minutes with microCi14C-urea. Urease-positive mycobacteria gave Bactec growth index (GI) values greater than 100 units, whereas urease-negative species gave values less than 10 GI units. Eighty-three isolates possessing neat urease activity were heated at 80 degrees C for 30 minutes followed by incubation at 35 degrees C for 30 minutes with 1 microCi14C-urea. Mycobacterium tuberculosis-bovis complex demonstrated heat-stable urease activity (GI more than 130 units) and could be distinguished from mycobacteria other than tuberculosis (MOTT), which gave GI values equal to or less than 40 units

  16. A stable isotope approach for source apportionment of chlorinated ethene plumes at a complex multi-contamination events urban site

    Science.gov (United States)

    Nijenhuis, Ivonne; Schmidt, Marie; Pellegatti, Eleonora; Paramatti, Enrico; Richnow, Hans Hermann; Gargini, Alessandro

    2013-10-01

    The stable carbon isotope composition of chlorinated aliphatic compounds such as chlorinated methanes, ethanes and ethenes was examined as an intrinsic fingerprint for apportionment of sources. A complex field site located in Ferrara (Italy), with more than 50 years history of use of chlorinated aliphatic compounds, was investigated in order to assess contamination sources. Several contamination plumes were found in a complex alluvial sandy multi-aquifer system close to the river Po; sources are represented by uncontained former industrial and municipal dump sites as well as by spills at industrial areas. The carbon stable isotope signature allowed distinguishing 2 major sources of contaminants. One source of chlorinated aliphatic contaminants was strongly depleted in 13C (-40‰ which is commonly observed in recent production of chlorinated solvents. The degradation processes in the plumes could be traced interpreting the isotope enrichment and depletion of parent and daughter compounds, respectively. We demonstrate that, under specific production conditions, namely when highly chlorinated ethenes are produced as by-product during chloromethanes production, 13C depleted fingerprinting of contaminants can be obtained and this can be used to track sources and address the responsible party of the pollution in urban areas.

  17. Integration as the basis of stable and dynamic development of enterprises in agroindustrial complex

    Directory of Open Access Journals (Sweden)

    Petr Ivanovich Ogorodnikov

    2011-12-01

    Full Text Available Formation of market relations in Russian economy generates an objective need to address a number of problems in the relationship between agroundustrial complex organizations in connection with privatization, liberalization of prices and imbalances in the existing inter-industry production and economic relations that negatively affect the results of their economic activities. Because of the flagrant violations of the replenishment process, a diverse range of connections and relationships between producers and processors was broken. The major direction of lifting agricultural economy in this situation is the development of cooperatives and agroindustrial integration. In addition, the formation of large integrated complexes demonstrates high efficiency and rapid development, which is the basis of agroindustrial sector in many developed countries. The increase of competition forces business entities to combine capabilities and mutually beneficial cooperation in the struggle for the strengthening of market positions. Thus, increasing the degree of integration in the agricultural sector helps to get out of the protracted crisis and move more quickly to the innovations.

  18. Emergence of a complex and stable network in a model ecosystem with extinction and mutation.

    Science.gov (United States)

    Tokita, Kei; Yasutomi, Ayumu

    2003-03-01

    We propose a minimal model of the dynamics of diversity-replicator equations with extinction, invasion and mutation. We numerically study the behavior of this simple model and show that it displays completely different behavior from the conventional replicator equation and the generalized Lotka-Volterra equation. We reach several significant conclusions as follows: (1) a complex ecosystem can emerge when mutants with respect to species-specific interaction are introduced; (2) such an ecosystem possesses strong resistance to invasion; (3) a typical fixation process of mutants is realized through the rapid growth of a group of mutualistic mutants with higher fitness than majority species; (4) a hierarchical taxonomic structure (like family-genus-species) emerges; and (5) the relative abundance of species exhibits a typical pattern widely observed in nature. Several implications of these results are discussed in connection with the relationship of the present model to the generalized Lotka-Volterra equation.

  19. Identifying apparent local stable isotope equilibrium in a complex non-equilibrium system.

    Science.gov (United States)

    He, Yuyang; Cao, Xiaobin; Wang, Jianwei; Bao, Huiming

    2018-02-28

    Although being out of equilibrium, biomolecules in organisms have the potential to approach isotope equilibrium locally because enzymatic reactions are intrinsically reversible. A rigorous approach that can describe isotope distribution among biomolecules and their apparent deviation from equilibrium state is lacking, however. Applying the concept of distance matrix in graph theory, we propose that apparent local isotope equilibrium among a subset of biomolecules can be assessed using an apparent fractionation difference (|Δα|) matrix, in which the differences between the observed isotope composition (δ') and the calculated equilibrium fractionation factor (1000lnβ) can be more rigorously evaluated than by using a previous approach for multiple biomolecules. We tested our |Δα| matrix approach by re-analyzing published data of different amino acids (AAs) in potato and in green alga. Our re-analysis shows that biosynthesis pathways could be the reason for an apparently close-to-equilibrium relationship inside AA families in potato leaves. Different biosynthesis/degradation pathways in tubers may have led to the observed isotope distribution difference between potato leaves and tubers. The analysis of data from green algae does not support the conclusion that AAs are further from equilibrium in glucose-cultured green algae than in the autotrophic ones. Application of the |Δα| matrix can help us to locate potential reversible reactions or reaction networks in a complex system such as a metabolic system. The same approach can be broadly applied to all complex systems that have multiple components, e.g. geochemical or atmospheric systems of early Earth or other planets. Copyright © 2017 John Wiley & Sons, Ltd.

  20. Directly transport of suspended matter from the Yangtze River to the Okinawa trough post-major flood '98: evidence from stable isotopes and C/N ratios

    International Nuclear Information System (INIS)

    Cai Deling; Shi Xuefa; Song Xiaohong

    2007-01-01

    Water column concentrations of total suspended matter (TSM), particulate organic carbon (POC), particulate nitrogen (PN) and their stable isotopic compositions (δ 13 C and δ 15 N) are measured at two to five different depths in the Yellow Sea and East China Seas and Yangtze Estuary to clarify the effect of '98 Yangtze great flood on the transport of suspended matter in the Yellow Sea and East China Sea. Suspended matters are collected to analyze the distributions of TSM, POC, PN and salinity throughout the Yellow Sea and East China Sea in the autumn of 1998. There are marked positive correlations (r=0.89-0.98) among TSM, POC and PN, but negative relationships (r=-0.29 - -0.59) between TSM and salinity. These results conclude that the POC and PN were controlled primarily by the concentrations of TSM. The C/N ratios of particulate organic matter have a negative linear correlation with PN% (r=-0.44 - -0.71), but no correlation with POC%, which suggests C/N ratios are mainly controlled by PN%. There are distinct positive correlations between δ 15 N and POC% or PN% in surface water (r=0.36 and 0.24, p<0.01, respectively), however, the correlation do not exist in more deeper depths. In indicates that δ 15 N PN could be changed by a lot of factors, such as nutrient availability, nitrification, denitrification, different material sources and so on, except decomposition of organic matter. The distributions of C/N ratios and δ 13 C values of the particulate organic matter suggest that suspended matters from Yangtze River could be transported directly into the Okinawa Trough under the condition of '98 Yangtze major flood, which break through the foregone knowledge obtained under the normal hydrological condition. (authors)

  1. Highly Manufacturable Deep (Sub-Millimeter) Etching Enabled High Aspect Ratio Complex Geometry Lego-Like Silicon Electronics.

    Science.gov (United States)

    Ghoneim, Mohamed Tarek; Hussain, Muhammad Mustafa

    2017-04-01

    A highly manufacturable deep reactive ion etching based process involving a hybrid soft/hard mask process technology shows high aspect ratio complex geometry Lego-like silicon electronics formation enabling free-form (physically flexible, stretchable, and reconfigurable) electronic systems. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Highly Manufacturable Deep (Sub-Millimeter) Etching Enabled High Aspect Ratio Complex Geometry Lego-Like Silicon Electronics

    KAUST Repository

    Ghoneim, Mohamed T.

    2017-02-01

    A highly manufacturable deep reactive ion etching based process involving a hybrid soft/hard mask process technology shows high aspect ratio complex geometry Lego-like silicon electronics formation enabling free-form (physically flexible, stretchable, and reconfigurable) electronic systems.

  3. How do soil types affect stable isotope ratios of 2H and 18O under evaporation: A Fingerprint of the Niipele subbasin of the Cuvelai - Etosha basin, Namibia.

    Science.gov (United States)

    Gaj, Marcel; Beyer, Matthias; Hamutoko, Josefina; Uugulu, Shoopi; Wanke, Heike; Koeniger, Paul; Kuells, Christoph; Lohe, Christoph; Himmelsbach, Thomas

    2014-05-01

    Northern Namibia is a region with high population growth, limited water resources and a transboundary aquifer system where groundwater recharge and groundwater flow processes are not well understood. This study is an interdisciplinary approach within the frame of SASSCAL (Southern African Science Service Centre for Climate Change and Adaptive Land Management) to improve the understanding of links between hydrological, geochemical and ecological processes to locate areas that contribute to recharge a shallow aquifer system in the Cuvelai-Etosha basin. Results of a field campaign are presented, conducted in November 2013 which is the first of a series planned between the years 2013 and 2016. Soil samples were taken in the semi-arid subbasin of the Cuvelai Etosha surface water basin before the rainy season. Potential evaporation, temperature measurements and infiltration tests were performed at two sites with different soil characteristics. Soil samples were taken under natural conditions to a maximum depth of 4 meters. Additionally to environmental isotope signals (stable isotopes 2H, and 18O and water of known isotopic composition (local groundwater) has been applied to the same plots. Soil samples were taken to a depth of 1 m with an interval of 10 cm after 24 and 48 hours for an investigation of evaporation impact on stable isotope ratios. The soil water is extracted cryogenically from the soil samples in the laboratory and subsequently analyzed using a Picarro L2120-i cavity-ringdown (CRD) water vapor analyzer after vaporization. Results of the direct measurement of different soil types indicate that evaporation from a saturated soil can exceed potential evaporation from an open water surface1. This implies, alternative methods are needed for the determination of evaporation which will be discussed here. 1Brutsaert W.; Parlanget M.B. (1998): Hydrologic cycle explains the evaporation paradox. In: Nature (396), p. 30.

  4. The Enhanced Intramolecular Energy Transfer and Strengthened ff Luminescence of a Stable Helical Eu Complex in Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Yuki Hasegawa

    2018-01-01

    Full Text Available The luminescence of a Eu complex (EuL is enhanced by stabilization of the coordination structure in highly viscous ionic liquids. The EuL was found to maintain a stable single helical structure both in organic solvents and in the ionic liquids [BMIM][PF6] and [EMIM][PF6]. A colorless solution of EuL dissolved in [BMIM][PF6] exhibits bright red luminescence with a quantum yield of 32.3%, a value that is much higher than that in acetonitrile (12%. Estimated rate constants for the energy relaxation pathway indicate that the energy transfer efficiency is enhanced in [BMIM][PF6] as a result of the suppression of molecular fluctuations in the ligands. Additionally, a highly luminescent helical structure is preserved in [EMIM][PF6] up to 120 °C.

  5. A conifer-friendly high-throughput α-cellulose extraction method for δ13C and δ18O stable isotope ratio analysis

    Science.gov (United States)

    Lin, W.; Noormets, A.; domec, J.; King, J. S.; Sun, G.; McNulty, S.

    2012-12-01

    Wood stable isotope ratios (δ13C and δ18O) offer insight to water source and plant water use efficiency (WUE), which in turn provide a glimpse to potential plant responses to changing climate, particularly rainfall patterns. The synthetic pathways of cell wall deposition in wood rings differ in their discrimination ratios between the light and heavy isotopes, and α-cellulose is broadly seen as the best indicator of plant water status due to its local and temporal fixation and to its high abundance within the wood. To use the effects of recent severe droughts on the WUE of loblolly pine (Pinus taeda) throughout Southeastern USA as a harbinger of future changes, an effort has been undertaken to sample the entire range of the species and to sample the isotopic composition in a consistent manner. To be able to accommodate the large number of samples required by this analysis, we have developed a new high-throughput method for α-cellulose extraction, which is the rate-limiting step in such an endeavor. Although an entire family of methods has been developed and perform well, their throughput in a typical research lab setting is limited to 16-75 samples per week with intensive labor input. The resin exclusion step in conifersis is particularly time-consuming. We have combined the recent advances of α-cellulose extraction in plant ecology and wood science, including a high-throughput extraction device developed in the Potsdam Dendro Lab and a simple chemical-based resin exclusion method. By transferring the entire extraction process to a multiport-based system allows throughputs of up to several hundred samples in two weeks, while minimizing labor requirements to 2-3 days per batch of samples.

  6. Quantifying sediment source contributions in coastal catchments impacted by the Fukushima nuclear accident with carbon and nitrogen elemental concentrations and stable isotope ratios

    Science.gov (United States)

    Laceby, J. Patrick; Huon Huon, Sylvain; Onda, Yuichi; Evrard, Olivier

    2016-04-01

    The Fukushima Dai-ichi Nuclear Power Plant accidental release of radioactive contaminants resulted in the significant fallout of radiocesium over several coastal catchments in the Fukushima Prefecture. Radiocesium, considered to be the greatest risk to the short and long term health of the local community, is rapidly bound to fine soil particles and thus is mobilized and transported during soil erosion and runoff processes. As there has been a broad-scale decontamination of rice paddy fields and rural residential areas in the contaminated region, one important long term question is whether there is, or may be, a downstream transfer of radiocesium from forests that covered over 65% of the most contaminated region. Accordingly, carbon and nitrogen elemental concentrations and stable isotope ratios are used to determine the relative contributions of forests and rice paddies to transported sediment in three contaminated coastal catchments. Samples were taken from the three main identified sources: cultivated soils (rice paddies and fields, n=30), forest soils (n=45), and subsoils (channel bank and decontaminated soils, n = 25). Lag deposit sediment samples were obtained from five sampling campaigns that targeted the main hydrological events from October 2011 to October 2014. In total, 86 samples of deposited sediment were analyzed for particulate organic matter elemental concentrations and isotope ratios, 24 from the Mano catchment, 44 from the Niida catchment, and 18 from the Ota catchment. Mann-Whitney U-tests were used to examine the source discrimination potential of this tracing suite and select the appropriate tracers for modelling. The discriminant tracers were modelled with a concentration-dependent distribution mixing model. Preliminary results indicate that cultivated sources (predominantly rice paddies) contribute disproportionately more sediment per unit area than forested regions in these contaminated catchments. Future research will examine if there are

  7. Stable carbon isotope analyses of nanogram quantities of particulate organic carbon (pollen) with laser ablation nano combustion gas chromatography/isotope ratio mass spectrometry

    Science.gov (United States)

    Sluijs, Appy; Laks, Jelmer J.; Reichart, Gert‐Jan

    2016-01-01

    Rationale Analyses of stable carbon isotope ratios (δ 13C values) of organic and inorganic matter remains have been instrumental for much of our understanding of present and past environmental and biological processes. Until recently, the analytical window of such analyses has been limited to samples containing at least several μg of carbon. Methods Here we present a setup combining laser ablation, nano combustion gas chromatography and isotope ratio mass spectrometry (LA/nC/GC/IRMS). A deep UV (193 nm) laser is used for optimal fragmentation of organic matter with minimum fractionation effects and an exceptionally small ablation chamber and combustion oven are used to reduce the minimum sample mass requirement compared with previous studies. Results Analyses of the international IAEA CH‐7 polyethylene standard show optimal accuracy, and precision better than 0.5‰, when measuring at least 42 ng C. Application to untreated modern Eucalyptus globulus (C3 plant) and Zea mays (C4 plant) pollen grains shows a ~ 16‰ offset between these species. Within each single Z. mays pollen grain, replicate analyses show almost identical δ 13C values. Conclusions Isotopic offsets between individual pollen grains exceed analytical uncertainties, therefore probably reflecting interspecimen variability of ~0.5–0.9‰. These promising results set the stage for investigating both δ 13C values and natural carbon isotopic variability between single specimens of a single population of all kinds of organic particles yielding tens of nanograms of carbon. © 2016 The Authors. Rapid Communications in Mass Spectrometry Published by John Wiley & Sons Ltd. PMID:27766694

  8. High-precision dual-inlet IRMS measurements of the stable isotopes of CO2 and the N2O / CO2 ratio from polar ice core samples

    Directory of Open Access Journals (Sweden)

    T. K. Bauska

    2014-11-01

    Full Text Available An important constraint on mechanisms of past carbon cycle variability is provided by the stable isotopic composition of carbon in atmospheric carbon dioxide (δ13C-CO2 trapped in polar ice cores, but obtaining very precise measurements has proven to be a significant analytical challenge. Here we describe a new technique to determine the δ13C of CO2 at very high precision, as well as measuring the CO2 and N2O mixing ratios. In this method, ancient air is extracted from relatively large ice samples (~400 g with a dry-extraction "ice grater" device. The liberated air is cryogenically purified to a CO2 and N2O mixture and analyzed with a microvolume-equipped dual-inlet IRMS (Thermo MAT 253. The reproducibility of the method, based on replicate analysis of ice core samples, is 0.02‰ for δ13C-CO2 and 2 ppm and 4 ppb for the CO2 and N2O mixing ratios, respectively (1σ pooled standard deviation. Our experiments show that minimizing water vapor pressure in the extraction vessel by housing the grating apparatus in a ultralow-temperature freezer (−60 °C improves the precision and decreases the experimental blank of the method to −0.07 ± 0.04‰. We describe techniques for accurate calibration of small samples and the application of a mass-spectrometric method based on source fragmentation for reconstructing the N2O history of the atmosphere. The oxygen isotopic composition of CO2 is also investigated, confirming previous observations of oxygen exchange between gaseous CO2 and solid H2O within the ice archive. These data offer a possible constraint on oxygen isotopic fractionation during H2O and CO2 exchange below the H2O bulk melting temperature.

  9. Signal-to-Noise ratio and design complexity based on Unified Loss ...

    African Journals Online (AJOL)

    Taguchi's quality loss function for larger-the-better performance characteristics uses a reciprocal transformation to compute quality loss. This paper suggests that reciprocal transformation unnecessarily complicates and may distort results. Examples of this distortion include the signal-to-noise ratio based on mean squared ...

  10. Temporal changes in carbon and nitrogen stable isotope ratios of macrozoobenthos on an artificial tidal flat facing a hypertrophic canal, inner Tokyo Bay

    International Nuclear Information System (INIS)

    Kanaya, Gen; Nakamura, Yasuo; Koizumi, Tomoyoshi; Yamada, Katsumasa; Koshikawa, Hiroshi; Kohzu, Ayato; Maki, Hideaki

    2013-01-01

    Highlights: • Temporal changes in food web structure were analyzed in a tidal flat in a hypertrophic coastal bay. • Microphytobenthos mainly supported the benthic food web throughout seasons. • Phytoplankton and terrestrial detritus were utilized after red tides and urban runoffs. • Seasonal changes in consumer-δ 15 N was much larger in inner Tokyo Bay than in other estuaries. • This study showed specific characteristics of benthic food web in highly urbanized estuaries. -- Abstract: Temporal changes in benthic food web structure were analyzed in an artificial tidal flat in inner Tokyo Bay, Japan, using carbon and nitrogen stable isotope ratios (δ 13 C and δ 15 N). Microphytobenthos were the most important food sources of macrozoobenthos, due to high microphytobenthic biomass on the tidal flat, while phytoplankton in canal water (canal POM PP ), terrestrial materials from urban surface runoff (canal POM TM ), and marsh plants were less important. Dietary contribution of microphytobenthos was highest in April to June, while decreased towards December owing to the supply of canal POM PP and canal POM TM following red tides and heavy rainfall events in summer to fall. Temporal changes in δ 15 N (Δδ 15 N) of consumer corresponded well to the 15 N-enrichment in canal POM PP in summer. A meta-analysis showed that the consumer-Δδ 15 N was considerably larger in inner Tokyo Bay than those in other estuaries, which may be a specific characteristic of benthic food web in highly urbanized estuaries

  11. New insights about the population structure of the blue jack mackerel (Trachurus picturatus in the NE Atlantic using otolith stable isotope ratios

    Directory of Open Access Journals (Sweden)

    Cláudia Moreira

    2015-11-01

    Full Text Available The blue jack mackerel Trachurus picturatus is a pelagic fish widely distributed in the NE Atlantic and also found in the Mediterranean and Black Seas. It is an economically important resource in the Macaronesian islands of Azores, Madeira and Canaries, but despite its fishery value and ecological importance, fluctuations in the landings are difficult to explain since studies regarding the population dynamics, stocks structure, fish movements and habitat connectivity are inexistent. The populations of marine pelagic fishes, in particular the migratory ones, such as T. picturatus,, may be erroneously considered an homogenous population unit because they show broad geographic distributions, large population sizes and high migratory movements. Stable isotope ratios, namely δ18O and δ13C, measured by standard mass spectrometric techniques in whole otolith samples of T. picturatus adults sampled in the fishery grounds of the Islands of Azores, Madeira and Canaries, and at the Portuguese mainland (Matosinhos, Peniche and Portimão during the spring-summer of 2013 were analysed. The 18O signatures followed the general tendency taking into account the seawater temperatures of the sampling regions. 13C signatures showed however differences between the oceanic or continental origin of the fish. Both variables provided location-specific signatures. Further studies including mitochondrial and nuclear DNA studies are also been conducted to acquire new knowledge for fisheries conservation purposes.

  12. Single-step transesterification with simultaneous concentration and stable isotope analysis of fatty acid methyl esters by gas chromatography-combustion-isotope ratio mass spectrometry.

    Science.gov (United States)

    Panetta, Robert J; Jahren, A Hope

    2011-05-30

    Gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) is increasingly applied to food and metabolic studies for stable isotope analysis (δ(13) C), with the quantification of analyte concentration often obtained via a second alternative method. We describe a rapid direct transesterification of triacylglycerides (TAGs) for fatty acid methyl ester (FAME) analysis by GC-C-IRMS demonstrating robust simultaneous quantification of amount of analyte (mean r(2) =0.99, accuracy ±2% for 37 FAMEs) and δ(13) C (±0.13‰) in a single analytical run. The maximum FAME yield and optimal δ(13) C values are obtained by derivatizing with 10% (v/v) acetyl chloride in methanol for 1 h, while lower levels of acetyl chloride and shorter reaction times skewed the δ(13) C values by as much as 0.80‰. A Bland-Altman evaluation of the GC-C-IRMS measurements resulted in excellent agreement for pure oils (±0.08‰) and oils extracted from French fries (±0.49‰), demonstrating reliable simultaneous quantification of FAME concentration and δ(13) C values. Thus, we conclude that for studies requiring both the quantification of analyte and δ(13) C data, such as authentication or metabolic flux studies, GC-C-IRMS can be used as the sole analytical method. Copyright © 2011 John Wiley & Sons, Ltd.

  13. Heavy metals (As, Hg and V) and stable isotope ratios (δ13C and δ15N) in fish from Yellow River Estuary, China.

    Science.gov (United States)

    Liu, Yuan; Liu, Guijian; Yuan, Zijiao; Liu, Houqi; Lam, Paul K S

    2018-02-01

    The Yellow River Estuary is a significant fishery, but at present there are few studies about the concentrations of arsenic (As), mercury (Hg) and vanadium (V) in fish from this area, which might cause potential health risk to fish consumers. The aim of this study was to research on the accumulation and potential sources of heavy metals in the fish of the Yellow River Estuary. Arsenic, Hg, V and stable isotope ratios (δ 15 N and δ 13 C) in 11 species of 129 fish were analyzed. Results showed that the concentrations of As and Hg were all lower than the guideline levels established by international organizations and legal limits by several countries. The mean concentrations of V in samples in this study were significantly higher than the results of previous studies on other regions. Arsenic, Hg and V significantly differed across species (PHg, which could be explained by the positive correlation between Hg concentrations and δ 15 N in fish. Through estimation of daily intake of inorganic As (iAs), Hg and V via fish consumption, the heavy metal contamination level of fish samples fell in an acceptable range, indicating no potentially hazardous for human health. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Trace elements and stable isotope ratios (δ13C and δ15N) in fish from deep-waters of the Sulu Sea and the Celebes Sea

    International Nuclear Information System (INIS)

    Asante, Kwadwo Ansong; Agusa, Tetsuro; Kubota, Reiji; Mochizuki, Hiroko; Ramu, Karri; Nishida, Shuhei; Ohta, Suguru; Yeh, Hsin-ming; Subramanian, Annamalai; Tanabe, Shinsuke

    2010-01-01

    Trace elements (TEs) and stable isotope ratios (δ 15 N and δ 13 C) were analyzed in fish from deep-water of the Sulu Sea, the Celebes Sea and the Philippine Sea. Concentrations of V and Pb in pelagic fish from the Sulu Sea were higher than those from the Celebes Sea, whereas the opposite trend was observed for δ 13 C. High concentrations of Zn, Cu and Ag were found in non-migrant fish in deep-water, while Rb level was high in fish which migrate up to the epipelagic zone, probably resulting from differences in background levels of these TEs in each water environment or function of adaptation to deep-water by migrant and non-migrant species. Arsenic level in the Sulu Sea fish was positively correlated with δ 15 N, indicating biomagnification of arsenic. To our knowledge, this is the first study on relationship between diel vertical migration and TE accumulation in deep-water fish.

  15. The Effect of the Interannual Variability of the OH Sink on the Interannual Variability of the Atmospheric Methane Mixing Ratio and Carbon Stable Isotope Composition

    Science.gov (United States)

    Guillermo Nuñez Ramirez, Tonatiuh; Houweling, Sander; Marshall, Julia; Williams, Jason; Brailsford, Gordon; Schneising, Oliver; Heimann, Martin

    2013-04-01

    The atmospheric hydroxyl radical concentration (OH) varies due to changes in the incoming UV radiation, in the abundance of atmospheric species involved in the production, recycling and destruction of OH molecules and due to climate variability. Variability in carbon monoxide emissions from biomass burning induced by El Niño Southern Oscillation are particularly important. Although the OH sink accounts for the oxidation of approximately 90% of atmospheric CH4, the effect of the variability in the distribution and strength of the OH sink on the interannual variability of atmospheric methane (CH4) mixing ratio and stable carbon isotope composition (δ13C-CH4) has often been ignored. To show this effect we simulated the atmospheric signals of CH4 in a three-dimensional atmospheric transport model (TM3). ERA Interim reanalysis data provided the atmospheric transport and temperature variability from 1990 to 2010. We performed simulations using time dependent OH concentration estimations from an atmospheric chemistry transport model and an atmospheric chemistry climate model. The models assumed a different set of reactions and algorithms which caused a very different strength and distribution of the OH concentration. Methane emissions were based on published bottom-up estimates including inventories, upscaled estimations and modeled fluxes. The simulations also included modeled concentrations of atomic chlorine (Cl) and excited oxygen atoms (O(1D)). The isotopic signal of the sources and the fractionation factors of the sinks were based on literature values, however the isotopic signal from wetlands and enteric fermentation processes followed a linear relationship with a map of C4 plant fraction. The same set of CH4emissions and stratospheric reactants was used in all simulations. Two simulations were done per OH field: one in which the CH4 sources were allowed to vary interannually, and a second where the sources were climatological. The simulated mixing ratios and

  16. Effect of Cyclodextrin Complexation on the Aqueous Solubility and Solubility/Dose Ratio of Praziquantel

    OpenAIRE

    Maragos, Stratos; Archontaki, Helen; Macheras, Panos; Valsami, Georgia

    2009-01-01

    Praziquantel (PZQ), the primary drug of choice in the treatment of schistosomiasis, is a highly lipophilic drug that possesses high permeability and low aqueous solubility and is, therefore, classified as a Class II drug according to the Biopharmaceutics Classification System (BCS). In this work, β-cyclodextrin (β-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD) were used in order to determine whether increasing the aqueous solubility of a drug by complexation with CDs, a BCS-Class II compound ...

  17. The relationship between fractional flow reserve, platelet reactivity and platelet leukocyte complexes in stable coronary artery disease

    NARCIS (Netherlands)

    Sels, J.W.E.M.; Rutten, B.; Holten, van T.C.; Hillaert, M.A.K.; Waltenberger, J.; Pijls, N.H.J.; Pasterkamp, G.; Groot, de P.G.; Roest, M.

    2013-01-01

    Background: The presence of stenoses that significantly impair blood flow and cause myocardial ischemia negatively affects prognosis of patients with stable coronary artery disease. Altered platelet reactivity has been associated with impaired prognosis of stable coronary artery disease. Platelets

  18. Pan-Arctic concentrations of mercury and stable isotope ratios of carbon (δ{sup 13}C) and nitrogen (δ{sup 15}N) in marine zooplankton

    Energy Technology Data Exchange (ETDEWEB)

    Pomerleau, Corinne, E-mail: corinne.pomerleau@umanitoba.ca [Centre for Earth Observation Science, University of Manitoba, Winnipeg, MB R3T 2N2 (Canada); Greenland Institute of Natural Resources, Kivioq 2, Nuuk 3900, Greenland (Denmark); Stern, Gary A.; Pućko, Monika [Centre for Earth Observation Science, University of Manitoba, Winnipeg, MB R3T 2N2 (Canada); Foster, Karen L. [Foster Environmental, Peterborough, ON K9J 8L2 (Canada); Macdonald, Robie W. [Institute of Ocean Sciences, Fisheries and Oceans Canada, Sidney, BC V8L 4B2 (Canada); Fortier, Louis [Québec-Océan, Département de Biologie, Université Laval, Québec, QC G1V 0A6 (Canada)

    2016-05-01

    Zooplankton play a central role in marine food webs, dictating the quantity and quality of energy available to upper trophic levels. They act as “keystone” species in transfer of mercury (Hg) up through the marine food chain. Here, we present the first Pan-Arctic overview of total and monomethylmercury concentrations (THg and MMHg) and stable isotope ratios of carbon (δ{sup 13}C) and nitrogen (δ{sup 15}N) in selected zooplankton species by assembling data collected between 1998 and 2012 from six arctic regions (Laptev Sea, Chukchi Sea, southeastern Beaufort Sea, Canadian Arctic Archipelago, Hudson Bay and northern Baffin Bay). MMHg concentrations in Calanus spp., Themisto spp. and Paraeuchaeta spp. were found to increase with higher δ{sup 15}N and lower δ{sup 13}C. The southern Beaufort Sea exhibited both the highest THg and MMHg concentrations. Biomagnification of MMHg between Calanus spp. and two of its known predators, Themisto spp. and Paraeuchaeta spp., was greatest in the southern Beaufort Sea. Our results show large geographical variations in Hg concentrations and isotopic signatures for individual species related to regional ecosystem features, such as varying water masses and freshwater inputs, and highlight the increased exposure to Hg in the marine food chain of the southern Beaufort Sea. - Highlights: • Assessment of Pan-Arctic variability in zooplankton Hg concentrations • Increased exposure to Hg in the marine food chain of the southern Beaufort Sea • Zooplankton plays a central role in the Hg pathway within Arctic marine food webs.

  19. Reconstruction of water mass properties of the Western Mediterranean using stable isotope ratios (δ18O and δ13C) from Pinna nobilis shells

    Science.gov (United States)

    Garcia-March, Jose Rafael; Surge, Donna; Tena-Medialdea, Jose; Torres, Javi; Garcia-Martinez, Micaela

    2017-04-01

    We analysed the stable isotope ratios (δ18O and δ13C) from the calcite of the outer prismatic layer of 8 Pinna nobilis shells at a rate of c. 12-16 samples/year for years between 1997 and 2013. These produced 8 time series between 4 and 16 years long. The empty shells had been collected in two Spanish marine protected areas, Tabarca Island in Alicante and Columbretes Islands in Castellón (4 specimens each). For all shells we constrained the time of death within at least a halve year window. The present study completes previous calibrations by using recorded seawater temperature data during at least two years for each site, coinciding with part of the analysed periods in the shells. Our preliminary results clearly reflect the seasonality of the signal in δ18O values for the entire ontogeny of the individuals studied. However, one specimen from Tabarca Island sampled between years 4 and 11 (corresponding to real age) shows a clear ontogenetic change, with an abrupt reduction in the amplitude of the signal from age 6 to 11 for both δ18O and δ13C values. We hypothesize this pattern relates to the onset of first gonad maturation. Values of δ13C track δ18O values in most individuals, but 3 specimens show low amplitude. For all time series, δ13C values show a decreasing slope with ontogeny similar to previous observations in P. nobilis and other bivalves. Estimated seawater temperature from our δ18O time series reveals the potential of P. nobilis shells as valuable archives of Mediterranean temperature reconstructions in the context of climate change.

  20. Stable Isotope Evidence for a Complex Fluid Evolution of the Northwestern British Columbia Coast Ranges Related to Terrane Accretion

    Science.gov (United States)

    Moertle, J.; Holk, G. J.

    2015-12-01

    Stable isotope geochemistry reveals a complex fluid evolution for the Western Metamorphic Belt (WMB), Coast Ranges Batholith (CRB), Central Gneiss Complex (CGC) and Coast Ranges Megalineament (CRM). These fluids are a product of a complex tectonic history related to terrane accretion that includes oblique convergence, metamorphism, magmatism, and orogenic collapse. From W-to-E, these fluid systems are as follows. High-pressure greenschist-to-amphibolite facies metasedimentary rocks of the WMB record variable mineral δD (-61 to -104‰) and δ18O (e.g., quartz +9.6 to +13.4‰) values with multiple minerals in apparent isotopic equilibrium (T ~ 450-550°C) suggest a low W/R system dominated by metamorphic fluids. Variable and non-equilibrium δD (-53 to -143‰) and δ18O (e.g., biotite +2.3 to +5.3‰) values from diorites of the Quottoon pluton affected by the ductile CRM suggest a complex evolution that involved both metamorphic and meteoric-hydrothermal fluids in this dextral shear zone; these results differ from those 300 km along strike to the north that documented only metamorphic fluids in the CRM (Goldfarb et al., 1988). Our data and those of Magaritz and Taylor (1976) from granulite facies metasediments of the CGC and plutons of the western CRB reveal homogeneous δD values (-62 to -78‰) and a restricted range of δ18O values (e.g., quartz +8.5 to +11.5‰) with all minerals in equilibrium at T > 570°C indicate a system dominated by magmatic fluids. Calculated whole-rock δ18O values (~ +7‰) for the Quottoon pluton and CRB intrusive rocks suggest a mantle origin for these magmas. Reinterpretation of very low δD (< -150‰) and quartz-feldspar δ18O pairs that display extreme disequilibrium (feldspar δ18O values as low as -5‰) from the Ponder pluton, eastern CRB, and Hazelton Group point reveals that the major meteoric-hydrothermal system that affected these rocks was related to Eocene detachment faulting along the Shames Lake fault system, a

  1. Parkinson-dementia complex and development of a new stable isotope dilution assay for BMAA detection in tissue

    International Nuclear Information System (INIS)

    Snyder, Laura R.; Cruz-Aguado, Reyniel; Sadilek, Martin; Galasko, Douglas; Shaw, Christopher A.; Montine, Thomas J.

    2009-01-01

    β-Methylamino-L-alanine (BMAA) has been proposed as a global contributor to neurodegenerative diseases, including Parkinson-dementia complex (PDC) of Guam and Alzheimer's disease (AD). The literature on the effects of BMAA is conflicting with some but not all in vitro data supporting a neurotoxic action, and experimental animal data failing to replicate the pattern of neurodegeneration of these human diseases, even at very high exposures. Recently, BMAA has been reported in human brain from individuals afflicted with PDC or AD. Some of the BMAA in human tissue reportedly is freely extractable (free) while some is protein-associated and liberated by techniques that hydrolyze the peptide bond. The latter is especially intriguing since BMAA is a non-proteinogenic amino acid that has no known tRNA. We attempted to replicate these findings with techniques similar to those used by others; despite more than adequate sensitivity, we were unable to detect free BMAA. Recently, using a novel stable isotope dilution assay, we again were unable to detect free or protein-associated BMAA in human cerebrum. Here we review the development of our new assay for tissue detection of BMAA and show that we are able to detect free BMAA in liver but not cerebrum, nor do we detect any protein-associated BMAA in mice fed this amino acid. These studies demonstrate the importance of a sensitive and specific assay for tissue BMAA and seriously challenge the proposal that BMAA is accumulating in human brain.

  2. Serum Uric Acid Levels and Uric Acid/Creatinine Ratios in Stable Chronic Obstructive Pulmonary Disease (COPD) Patients: Are These Parameters Efficient Predictors of Patients at Risk for Exacerbation and/or Severity of Disease?

    Science.gov (United States)

    Durmus Kocak, Nagihan; Sasak, Gulsah; Aka Akturk, Ulku; Akgun, Metin; Boga, Sibel; Sengul, Aysun; Gungor, Sinem; Arinc, Sibel

    2016-11-03

    BACKGROUND Serum uric acid (sUA) levels were previously found to be correlated with hypoxic states. We aimed to determine the levels of sUA and sUA/creatinine ratios in stable COPD patients and to evaluate whether sUA level and sUA/creatinine ratio can be used as predictors of exacerbation risk and disease severity. MATERIAL AND METHODS This cross-sectional study included stable COPD patients and healthy controls. The sUA levels and sUA/creatinine ratios in each group were evaluated and their correlations with the study parameters were investigated. ROC analyses for exacerbation risk and disease severity were reported. RESULTS The study included 110 stable COPD patients and 52 healthy controls. The mean sUA levels and sUA/creatinine ratios were significantly higher in patients with COPD compared to healthy controls. The most common comorbidities in COPD patients were hypertension, diabetes, and coronary artery disease. While sUA levels were significantly higher in patients with hypertension (p=0.002) and malignancy (p=0.033), sUA/creatinine ratios was higher in patients with malignancy (p=0.004). The ROC analyses indicated that sUA/creatinine ratios can be more useful than sUA levels in predicting exacerbation risk (AUC, 0.586 vs. 0.426) and disease severity (AUC, 0.560 vs. 0.475) especially at higher cut-off values, but with low specificity. CONCLUSIONS Our study suggested that sUA levels and sUA/creatinine ratios increased in patients with stable COPD, especially among patients with certain comorbidities compared to healthy controls. At higher cut-off values, sUA levels and especially sUA/creatinine ratios, might be useful in predicting COPD exacerbation risk and disease severity. Also, their association with comorbidities, especially with malignancy and hypertension, may benefit from further investigation.

  3. A new method for precise determination of iron, zinc and cadmium stable isotope ratios in seawater by double-spike mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Conway, Tim M., E-mail: conway.tm@gmail.com [Department of Earth and Ocean Sciences, University of South Carolina, Columbia, SC 29208 (United States); Rosenberg, Angela D. [Department of Earth and Ocean Sciences, University of South Carolina, Columbia, SC 29208 (United States); Adkins, Jess F. [California Institute of Technology, Division of Geological and Planetary Sciences, Pasadena, CA 91125 (United States); John, Seth G. [Department of Earth and Ocean Sciences, University of South Carolina, Columbia, SC 29208 (United States)

    2013-09-02

    Graphical abstract: ‘Metal-free’ seawater doped with varying concentrations of ‘zero’ isotope standards, processed through our simultaneous method, and then analyzed by double spike MC-ICPMS for Fe, Zn and Cd isotope ratios. All values were determined within 2 σ error (error bars shown) of zero. -- Highlights: •The first simultaneous method for isotopic analysis of Fe, Zn and Cd in seawater. •Designed for 1 L samples, a 1–20 fold improvement over previous methods. •Low blanks and high precision allow measurement of low concentration samples. •Small volume and fast processing are ideal for high-resolution large-scale studies. •Will facilitate investigation of marine trace-metal isotope cycling. -- Abstract: The study of Fe, Zn and Cd stable isotopes (δ{sup 56}Fe, δ{sup 66}Zn and δ{sup 114}Cd) in seawater is a new field, which promises to elucidate the marine cycling of these bioactive trace metals. However, the analytical challenges posed by the low concentration of these metals in seawater has meant that previous studies have typically required large sample volumes, highly limiting data collection in the oceans. Here, we present the first simultaneous method for the determination of these three isotope systems in seawater, using Nobias PA-1 chelating resin to extract metals from seawater, purification by anion exchange chromatography, and analysis by double spike MC-ICPMS. This method is designed for use on only a single litre of seawater and has blanks of 0.3, 0.06 and <0.03 ng for Fe, Zn and Cd respectively, representing a 1–20 fold reduction in sample size and a 4–130 decrease in blank compared to previously reported methods. The procedure yields data with high precision for all three elements (typically 0.02–0.2‰; 1σ internal precision), allowing us to distinguish natural variability in the oceans, which spans 1–3‰ for all three isotope systems. Simultaneous extraction and purification of three metals makes this method ideal

  4. Cardio-Thoracic Ratio Is Stable, Reproducible and Has Potential as a Screening Tool for HIV-1 Related Cardiac Disorders in Resource Poor Settings.

    Directory of Open Access Journals (Sweden)

    Hanif Esmail

    Full Text Available Cardiovascular disorders are common in HIV-1 infected persons in Africa and presentation is often insidious. Development of screening algorithms for cardiovascular disorders appropriate to a resource-constrained setting could facilitate timely referral. Cardiothoracic ratio (CTR on chest radiograph (CXR has been suggested as a potential screening tool but little is known about its reproducibility and stability. Our primary aim was to evaluate the stability and the inter-observer variability of CTR in HIV-1 infected outpatients. We further evaluated the prevalence of cardiomegaly (CTR≥0.5 and its relationship with other risk factors in this population.HIV-1 infected participants were identified during screening for a tuberculosis vaccine trial in Khayelitsha, South Africa between August 2011 and April 2012. Participants had a digital posterior-anterior CXR performed as well as history, examination and baseline observations. CXRs were viewed using OsiriX software and CTR calculated using digital callipers.450 HIV-1-infected adults were evaluated, median age 34 years (IQR 30-40 with a CD4 count 566/mm3 (IQR 443-724, 70% on antiretroviral therapy (ART. The prevalence of cardiomegaly was 12.7% (95% C.I. 9.6%-15.8%. CTR was calculated by a 2nd reader for 113 participants, measurements were highly correlated r = 0.95 (95% C.I. 0.93-0.97 and agreement of cardiomegaly substantial κ = 0.78 (95% C.I 0.61-0.95. CXR were repeated in 51 participants at 4-12 weeks, CTR measurements between the 2 time points were highly correlated r = 0.77 (95% C.I 0.68-0.88 and agreement of cardiomegaly excellent κ = 0.92 (95% C.I. 0.77-1. Participants with cardiomegaly had a higher median BMI (31.3; IQR 27.4-37.4 versus 26.9; IQR 23.2-32.4; p<0.0001 and median systolic blood pressure (130; IQR 121-141 versus 125; IQR 117-135; p = 0.01.CTR is a robust measurement, stable over time with substantial inter-observer agreement. A prospective study evaluating utility of CXR to

  5. A new method for precise determination of iron, zinc and cadmium stable isotope ratios in seawater by double-spike mass spectrometry

    International Nuclear Information System (INIS)

    Conway, Tim M.; Rosenberg, Angela D.; Adkins, Jess F.; John, Seth G.

    2013-01-01

    Graphical abstract: ‘Metal-free’ seawater doped with varying concentrations of ‘zero’ isotope standards, processed through our simultaneous method, and then analyzed by double spike MC-ICPMS for Fe, Zn and Cd isotope ratios. All values were determined within 2 σ error (error bars shown) of zero. -- Highlights: •The first simultaneous method for isotopic analysis of Fe, Zn and Cd in seawater. •Designed for 1 L samples, a 1–20 fold improvement over previous methods. •Low blanks and high precision allow measurement of low concentration samples. •Small volume and fast processing are ideal for high-resolution large-scale studies. •Will facilitate investigation of marine trace-metal isotope cycling. -- Abstract: The study of Fe, Zn and Cd stable isotopes (δ 56 Fe, δ 66 Zn and δ 114 Cd) in seawater is a new field, which promises to elucidate the marine cycling of these bioactive trace metals. However, the analytical challenges posed by the low concentration of these metals in seawater has meant that previous studies have typically required large sample volumes, highly limiting data collection in the oceans. Here, we present the first simultaneous method for the determination of these three isotope systems in seawater, using Nobias PA-1 chelating resin to extract metals from seawater, purification by anion exchange chromatography, and analysis by double spike MC-ICPMS. This method is designed for use on only a single litre of seawater and has blanks of 0.3, 0.06 and <0.03 ng for Fe, Zn and Cd respectively, representing a 1–20 fold reduction in sample size and a 4–130 decrease in blank compared to previously reported methods. The procedure yields data with high precision for all three elements (typically 0.02–0.2‰; 1σ internal precision), allowing us to distinguish natural variability in the oceans, which spans 1–3‰ for all three isotope systems. Simultaneous extraction and purification of three metals makes this method ideal for high

  6. Increase in soil stable carbon isotope ratio relates to loss of organic carbon: results from five long-term bare fallow experiments.

    Science.gov (United States)

    Menichetti, Lorenzo; Houot, Sabine; van Oort, Folkert; Kätterer, Thomas; Christensen, Bent T; Chenu, Claire; Barré, Pierre; Vasilyeva, Nadezda A; Ekblad, Alf

    2015-03-01

    Changes in the (12)C/(13)C ratio (expressed as δ(13)C) of soil organic C (SOC) has been observed over long time scales and with depth in soil profiles. The changes are ascribed to the different reaction kinetics of (12)C and (13)C isotopes and the different isotopic composition of various SOC pool components. However, experimental verification of the subtle isotopic shifts associated with SOC turnover under field conditions is scarce. We determined δ(13)C and SOC in soil sampled during 1929-2009 in the Ap-horizon of five European long-term bare fallow experiments kept without C inputs for 27-80 years and covering a latitudinal range of 11°. The bare fallow soils lost 33-65% of their initial SOC content and showed a mean annual δ(13)C increase of 0.008-0.024‰. The (13)C enrichment could be related empirically to SOC losses by a Rayleigh distillation equation. A more complex mechanistic relationship was also examined. The overall estimate of the fractionation coefficient (ε) was -1.2 ± 0.3‰. This coefficient represents an important input to studies of long-term SOC dynamics in agricultural soils that are based on variations in (13)C natural abundance. The variance of ε may be ascribed to site characteristics not disclosed in our study, but the very similar kinetics measured across our five experimental sites suggest that overall site-specific factors (including climate) had a marginal influence and that it may be possible to isolate a general mechanism causing the enrichment, although pre-fallow land use may have some impact on isotope abundance and fractionation.

  7. Stable X chromosome inactivation involves the PRC1 Polycomb complex and requires histone MACROH2A1 and the CULLIN3/SPOP ubiquitin E3 ligase

    DEFF Research Database (Denmark)

    Hernández-Muñoz, Inmaculada; Lund, Anders H; van der Stoop, Petra

    2005-01-01

    X inactivation involves the stable silencing of one of the two X chromosomes in XX female mammals. Initiation of this process occurs during early development and involves Xist (X-inactive-specific transcript) RNA coating and the recruitment of Polycomb repressive complex (PRC) 2 and PRC1 proteins...

  8. Liquid and gas chromatography coupled to isotope ratio mass spectrometry for the determination of 13C-valine isotopic ratios in complex biological samples

    NARCIS (Netherlands)

    Godin, Jean-Philippe; Breuillé, Denis; Obled, Christiane; Papet, Isabelle; Schierbeek, Henk; Hopfgartner, Gérard; Fay, Laurent-Bernard

    2008-01-01

    On-line gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) is commonly used to measure isotopic ratios at natural abundance as well as for tracer studies in nutritional and medical research. However, high-precision (13)C isotopic enrichment can also be measured by liquid

  9. Experimental and numerical study of atmospheric turbulence and dispersion in stable conditions and in near field at a complex site

    International Nuclear Information System (INIS)

    Wei, Xiao

    2016-01-01

    An experimental program has been designed in order to study pollutants dispersion at a complex site with a focus on stable conditions, which are still challenging for numerical modelling. This experimental program is being conducted at the SIRTA site in a southern suburb of Paris and consists in measuring, in near field, the turbulence and the pollutants dispersion. The aim of this program is to characterize the fine structure of turbulence and associated dispersion through high temporal and spatial resolution measurements. Then, these measurements allow to validate and improve the performance of CFD simulation for turbulence and dispersion in a heterogeneous field. The instrumental set up includes 12 ultrasonic anemometers measuring continuously wind velocity and temperature at 10 Hz, and 6 photo-ionization detectors (PIDs) measuring gas concentration at 50 Hz during tracer tests. Intensive observations periods (IOPs) with gas releases have been performed since March 2012. First of all, a detailed study of flow on the site is made, because it must be characterised and properly simulated before attempting to simulate the pollutants dispersion. This study is based on two years of continuous measurements and on measurements performed during IOPs. Turbulence strong anisotropy in the surface layer is characterized by calculating variances, integral length scales and power spectra of the three wind velocity components. Propagation of turbulent structures between sensors has been characterized with velocity correlations. Energy spectra show several slopes in different frequency regions. Also, data analyses show impact of terrain heterogeneity on the measurements. The forest to the north of the experimental field modifies wind velocity and direction for a large northerly sector. It induces a strong directional wind shear and a wind deceleration below the forest height. Numerical simulations are carried out using the CFD code, Code-Saturne, in RANS mode with a standard k

  10. Experimental and numerical study of atmospheric turbulence and dispersion in stable conditions and in near field at a complex site

    International Nuclear Information System (INIS)

    Wei, Xiao

    2016-01-01

    An experimental program has been designed in order to study pollutants dispersion at a complex site with a focus on stable conditions, which are still challenging for numerical modelling. This experimental program is being conducted at the SIRTA site in a southern suburb of Paris and consists in measuring, in near field, the turbulence and the pollutants dispersion. The aim of this program is to characterize the fine structure of turbulence and associated dispersion through high temporal and spatial resolution measurements. Then, these measurements allow to validate and improve the performance of CFD simulation for turbulence and dispersion in a heterogeneous field. The instrumental set up includes 12 ultrasonic anemometers measuring continuously wind velocity and temperature at 10 Hz, and 6 photo-ionization detectors (PIDs) measuring gas concentration at 50 Hz during tracer tests. Intensive observations periods (IOPs) with gas releases have been performed since March 2012.First of all, a detailed study of flow on the site is made, because it must be characterised and properly simulated before attempting to simulate the pollutants dispersion. This study is based on two years of continuous measurements and on measurements performed during IOPs. Turbulence strong anisotropy in the surface layer is characterized by calculating variances, integral length scales and power spectra of the three wind velocity components. Propagation of turbulent structures between sensors has been characterized with velocity correlations. Energy spectra show several slopes in different frequency regions. Also, data analyses show impact of terrain heterogeneity on the measurements. The forest to the north of experimental field modifies wind velocity and direction for a large northerly sector. It induces a strong directional wind shear and a wind deceleration below the forest height. Numerical simulations are carried out using the CFD code Code-Saturne in RANS mode with a standard κ

  11. Inert and stable erbium(III)-cored complexes based on metalloporphyrins bearing aryl-ether dendron for optical amplification: synthesis and emission enhancement

    International Nuclear Information System (INIS)

    Oh, Jae Buem; Kim, Yong Hee; Nah, Min Kook; Kim, Hwan Kyu

    2005-01-01

    We have developed novel inert and stable erbium (Er)(III)-cored complexes based on metalloporphyrins for optical amplification. The functionalized metalloporphyrin ligands have been designed and synthesized to provide enough coordination sites for the formation of inert and stable 9-coordinated Er(III)-cored complexes. Er 3+ ions were encapsulated by the metalloporphyrin ligands, such as Zn(II)- and Pt(II)-porphyrins. The near-infrared (IR) emission intensity of Er 3+ ion is much stronger in the Er(III)-cored complex based on Pt(II)-porphyrin than Er(III)-cored complex based on Zn(II)-porphyrin. Furthermore, we have incorporated a G2-aryl-ether functionalized dendron into the Er(III)-cored complex, yielding an Er(III)-cored dendrimer complex bearing the Pt(II)-porphyrin. The Er(III)-cored dendrimer complex shows the stronger near-IR emission intensity than the corresponding complex based on Pt(II)-porphyrin by seven times in solid state. The lifetimes of the emission band of Pt(II)-porphyrin ligands in the visible region were found to be 30 and 40 μs for the Er(III)-cored complex and the Er(III)-cored dendrimer complex based on Pt(II)-porphyrin in deoxygenated THF solution samples, respectively. Also, in both cases, the sensitized luminescence intensity is increased in deoxygenated solution. Therefore, it indicates that the energy transfer from the metalloporphyrins to Er 3+ ions takes places through the triplet state. In this paper, the synthesis and photophysical properties of novel Er(III)-cored complexes based on metalloporphyrins and Er(III)-cored dendrimer complex based on metalloporphyrin will be discussed

  12. Analysis of stable isotope ratios (δ18O and δ2H) in precipitation of the Verde River watershed, Arizona 2003 through 2014

    Science.gov (United States)

    Beisner, Kimberly R.; Paretti, Nicholas V.; Tucci, Rachel S.

    2016-04-25

    Stable isotope delta values (δ18O and δ2H) of precipitation can vary with elevation, and quantification of the precipitation elevation gradient can be used to predict recharge elevation within a watershed. Precipitation samples were analyzed for stable isotope delta values between 2003 and 2014 from the Verde River watershed of north-central Arizona. Results indicate a significant decrease in summer isotopic values overtime at 3,100-, 4,100-, 6,100-, 7,100-, and 8,100-feet elevation. The updated local meteoric water line for the area is δ2H = 7.11 δ18O + 3.40. Equations to predict stable isotopic values based on elevation were updated from previous publications in Blasch and others (2006), Blasch and Bryson (2007), and Bryson and others (2007). New equations were separated for samples from the Camp Verde to Flagstaff transect and the Prescott to Chino Valley transect. For the Camp Verde to Flagstaff transect, the new equations for winter precipitation are δ18O = -0.0004z − 8.87 and δ2H = -0.0029z − 59.8 (where z represents elevation in feet) and the summer precipitation equations were not statistically significant. For the Prescott to Chino Valley transect, the new equations for summer precipitation are δ18O = -0.0005z − 3.22 and δ2H = -0.0022z − 27.9; the winter precipitation equations were not statistically significant and, notably, stable isotope values were similar across all elevations. Interpretation of elevation of recharge contributing to surface and groundwaters in the Verde River watershed using the updated equations for the Camp Verde to Flagstaff transect will give lower elevation values compared with interpretations presented in the previous studies. For waters in the Prescott and Chino Valley area, more information is needed to understand local controls on stable isotope values related to elevation.

  13. Reproducibility over a 1-month period of (1)H-MR spectroscopic imaging NAA/Cr ratios in clinically stable multiple sclerosis patients

    NARCIS (Netherlands)

    Mostert, J. P.; Blaauw, Y.; Koch, M. W.; Kuiper, A. J.; Hoogduin, J. M.; De Keyser, J.

    N-acetylaspartate/creatine (NAA/Cr) ratios, assessed with proton magnetic resonance spectroscopy, are increasingly used as a surrogate marker for axonal dysfunction and degeneration in multiple sclerosis (MS). The purpose of this study was to test short-time reproducibility of NAA/Cr ratios in

  14. Expanding the Therapeutic Potential of the Iron Chelator Deferasirox in the Development of Aqueous Stable Ti(IV) Anticancer Complexes.

    Science.gov (United States)

    Loza-Rosas, Sergio A; Vázquez-Salgado, Alexandra M; Rivero, Kennett I; Negrón, Lenny J; Delgado, Yamixa; Benjamín-Rivera, Josué A; Vázquez-Maldonado, Angel L; Parks, Timothy B; Munet-Colón, Charlene; Tinoco, Arthur D

    2017-07-17

    The recent X-ray structure of titanium(IV)-bound human serum transferrin (STf) exhibiting citrate as a synergistic anion reveals a difference in Ti(IV) coordination versus iron(III), the metal endogenously delivered by the protein to cells. This finding enriches our bioinspired drug design strategy for Ti(IV)-based anticancer therapeutics, which applies a family of Fe(III) chelators termed chemical transferrin mimetic (cTfm) ligands to inhibit Fe bioavailability in cancer cells. Deferasirox, a drug used for iron overload disease, is a cTfm ligand that models STf coordination to Fe(III), favoring Fe(III) binding versus Ti(IV). This metal affinity preference drives deferasirox to facilitate the release of cytotoxic Ti(IV) intracellularly in exchange for Fe(III). An aqueous speciation study performed by potentiometric titration from pH 4 to 8 with micromolar levels of Ti(IV) deferasirox at a 1:2 ratio reveals exclusively Ti(deferasirox) 2 in solution. The predominant complex at pH 7.4, [Ti(deferasirox) 2 ] 2- , exhibits the one of the highest aqueous stabilities observed for a potent cytotoxic Ti(IV) species, demonstrating little dissociation even after 1 month in cell culture media. UV-vis and 1 H NMR studies show that the stability is unaffected by the presence of biomolecular Ti(IV) binders such as citrate, STf, and albumin, which have been shown to induce dissociation or regulate cellular uptake and can alter the activity of other antiproliferative Ti(IV) complexes. Kinetic studies on [Ti(deferasirox) 2 ] 2- transmetalation with Fe(III) show that a labile Fe(III) source is required to induce this process. The initial step of this process occurs on the time scale of minutes, and equilibrium for the complete transmetalation is reached on a time scale of hours to a day. This work reveals a mechanism to deliver Ti(IV) compounds into cells and trigger Ti(IV) release by a labile Fe(III) species. Cellular studies including other cTfm ligands confirm the Fe(III) depletion

  15. Online Stable Isotope Analysis of Dissolved Organic Carbon Size Classes Using Size Exclusion Chromatography Coupled to an Isotope Ratio Mass Spectrometer

    Digital Repository Service at National Institute of Oceanography (India)

    Malik, A.; Scheibe, A.; LokaBharathi, P.A.; Gleixner, G.

    size classes by coupling high-performance liquid chromatography (HPLC) - size exclusion chromatography (SEC) to online isotope ratio mass spectrometry (IRMS). This represents a significant methodological contribution to DOC research. The interface...

  16. Acute multi-sgRNA knockdown of KEOPS complex genes reproduces the microcephaly phenotype of the stable knockout zebrafish model.

    Directory of Open Access Journals (Sweden)

    Tilman Jobst-Schwan

    Full Text Available Until recently, morpholino oligonucleotides have been widely employed in zebrafish as an acute and efficient loss-of-function assay. However, off-target effects and reproducibility issues when compared to stable knockout lines have compromised their further use. Here we employed an acute CRISPR/Cas approach using multiple single guide RNAs targeting simultaneously different positions in two exemplar genes (osgep or tprkb to increase the likelihood of generating mutations on both alleles in the injected F0 generation and to achieve a similar effect as morpholinos but with the reproducibility of stable lines. This multi single guide RNA approach resulted in median likelihoods for at least one mutation on each allele of >99% and sgRNA specific insertion/deletion profiles as revealed by deep-sequencing. Immunoblot showed a significant reduction for Osgep and Tprkb proteins. For both genes, the acute multi-sgRNA knockout recapitulated the microcephaly phenotype and reduction in survival that we observed previously in stable knockout lines, though milder in the acute multi-sgRNA knockout. Finally, we quantify the degree of mutagenesis by deep sequencing, and provide a mathematical model to quantitate the chance for a biallelic loss-of-function mutation. Our findings can be generalized to acute and stable CRISPR/Cas targeting for any zebrafish gene of interest.

  17. Cation and anion dependence of stable geometries and stabilization energies of alkali metal cation complexes with FSA(-), FTA(-), and TFSA(-) anions: relationship with physicochemical properties of molten salts.

    Science.gov (United States)

    Tsuzuki, Seiji; Kubota, Keigo; Matsumoto, Hajime

    2013-12-19

    Stable geometries and stabilization energies (Eform) of the alkali metal complexes with bis(fluorosulfonyl)amide, (fluorosulfonyl)(trifluoromethylslufonyl)amide and bis(trifluoromethylsulfonyl)amide (FSA(-), FTA(-) and TFSA(-)) were studied by ab initio molecular orbital calculations. The FSA(-) complexes prefer the bidentate structures in which two oxygen atoms of two SO2 groups have contact with the metal cation. The FTA(-) and TFSA(-) complexes with Li(+) and Na(+) prefer the bidentate structures, while the FTA(-) and TFSA(-) complexes with Cs(+) prefer tridentate structures in which the metal cation has contact with two oxygen atoms of an SO2 group and one oxygen atom of another SO2 group. The two structures are nearly isoenergetic in the FTA(-) and TFSA(-) complexes with K(+) and Rb(+). The magnitude of Eform depends on the alkali metal cation significantly. The Eform calculated for the most stable TFSA(-) complexes with Li(+), Na(+), K(+), Rb(+) and Cs(+) cations at the MP2/6-311G** level are -137.2, -110.5, -101.1, -89.6, and -84.1 kcal/mol, respectively. The viscosity and ionic conductivity of the alkali TFSA molten salts have strong correlation with the magnitude of the attraction. The viscosity increases and the ionic conductivity decreases with the increase of the attraction. The melting points of the alkali TFSA and alkali BETA molten salts also have correlation with the magnitude of the Eform, which strongly suggests that the magnitude of the attraction play important roles in determining the melting points of these molten salts. The anion dependence of the Eform calculated for the complexes is small (less than 2.9 kcal/mol). This shows that the magnitude of the attraction is not the cause of the low melting points of alkali FTA molten salts compared with those of corresponding alkali TFSA molten salts. The electrostatic interactions are the major source of the attraction in the complexes. The electrostatic energies for the most stable TFSA

  18. Stable carbon isotope ratios as indicators of marine versus terrestrial inputs to the diets of wild and captive tuatara (Sphenodon punctatus)

    International Nuclear Information System (INIS)

    Cree, A.; Cartland-Shaw, L.; Tyrrell, C.; Lyon, G.L.

    1999-01-01

    Stable carbon isotope analysis was used to examine feeding relationships of wild tuatara on Stephens Island and captive tuatara in New Zealand institutions. We first measured delta 13 C in three food items of wild tuatara. Pectoral muscle of fairy prions (a seabird eaten seasonally by tuatara) was significantly enriched in 13 C compared with whole bodies of wild insects (darkling beetles and tree weta). Values for delta 13 C in blood cells varied significantly among wild tuatara of different life-history stages. Male tuatara were more enriched in 13 C than were females or juveniles, suggesting that males prey more heavily on seabirds. Insect foods of captive tuatara varied dramatically in delta/sup 13/C; this is attributed to differential consumption of plant material derived from the C 3 and C 4 photosynthetic pathways. Blood cells from four different groups of captive tuatara differed significantly in delta 13 C. This was perhaps related to assimilation of insects with different delta 13 C values, and cannot be attributed to differences in seabird predation as captive tuatara do not have access to seabirds. For wild tuatara on Stephens Island, stable carbon isotope analysis provides support for the dietary information available from behavioural observations, gut analyses and measurements of plasma composition. (author). 47 refs., 1 tab., 2 figs

  19. Combining functional weed ecology and crop stable isotope ratios to identify cultivation intensity: a comparison of cereal production regimes in Haute Provence, France and Asturias, Spain.

    Science.gov (United States)

    Bogaard, Amy; Hodgson, John; Nitsch, Erika; Jones, Glynis; Styring, Amy; Diffey, Charlotte; Pouncett, John; Herbig, Christoph; Charles, Michael; Ertuğ, Füsun; Tugay, Osman; Filipovic, Dragana; Fraser, Rebecca

    This investigation combines two independent methods of identifying crop growing conditions and husbandry practices-functional weed ecology and crop stable carbon and nitrogen isotope analysis-in order to assess their potential for inferring the intensity of past cereal production systems using archaeobotanical assemblages. Present-day organic cereal farming in Haute Provence, France features crop varieties adapted to low-nutrient soils managed through crop rotation, with little to no manuring. Weed quadrat survey of 60 crop field transects in this region revealed that floristic variation primarily reflects geographical differences. Functional ecological weed data clearly distinguish the Provence fields from those surveyed in a previous study of intensively managed spelt wheat in Asturias, north-western Spain: as expected, weed ecological data reflect higher soil fertility and disturbance in Asturias. Similarly, crop stable nitrogen isotope values distinguish between intensive manuring in Asturias and long-term cultivation with minimal manuring in Haute Provence. The new model of cereal cultivation intensity based on weed ecology and crop isotope values in Haute Provence and Asturias was tested through application to two other present-day regimes, successfully identifying a high-intensity regime in the Sighisoara region, Romania, and low-intensity production in Kastamonu, Turkey. Application of this new model to Neolithic archaeobotanical assemblages in central Europe suggests that early farming tended to be intensive, and likely incorporated manuring, but also exhibited considerable variation, providing a finer grained understanding of cultivation intensity than previously available.

  20. (Pyridine)(tetrahydroborato)zinc complex, (Zn(BH4)2(py)), as a new stable, efficient and chemoselective reducing agent for reduction of carbonyl compounds

    International Nuclear Information System (INIS)

    Zeynizadeh, Behzad; Faraji, Fariba

    2003-01-01

    (Pyridine)(tetrahydroborato)zinc complex, (Zn(BH 4 ) 2 (py)), as a stable white solid, was prepared quantitatively by complexation of an equimolar amount of zinc tetrahydroborate and pyridine at room temperature. This reagent can easily reduce variety of carbonyl compounds such as aldehydes, ketones, acyloins, α-diketones and α,β-unsaturated carbonyl compounds to their corresponding alcohols in good to excellent yields. Reduction reactions were performed in ether or THF at room temperature or under reflux conditions. In addition, the chemoselective reduction of aldehydes over ketones was accomplished successfully with this reducing agent

  1. (Pyridine)(tetrahydroborato)zinc complex, (Zn(BH{sub 4}){sub 2}(py)), as a new stable, efficient and chemoselective reducing agent for reduction of carbonyl compounds

    Energy Technology Data Exchange (ETDEWEB)

    Zeynizadeh, Behzad; Faraji, Fariba [Urima Univ., Urima (Iran, Islamic Republic of)

    2003-04-01

    (Pyridine)(tetrahydroborato)zinc complex, (Zn(BH{sub 4}){sub 2}(py)), as a stable white solid, was prepared quantitatively by complexation of an equimolar amount of zinc tetrahydroborate and pyridine at room temperature. This reagent can easily reduce variety of carbonyl compounds such as aldehydes, ketones, acyloins, {alpha}-diketones and {alpha},{beta}-unsaturated carbonyl compounds to their corresponding alcohols in good to excellent yields. Reduction reactions were performed in ether or THF at room temperature or under reflux conditions. In addition, the chemoselective reduction of aldehydes over ketones was accomplished successfully with this reducing agent.

  2. Profiling of new psychoactive substances (NPS) by using stable isotope ratio mass spectrometry (IRMS): study on the synthetic cannabinoid 5F-PB-22.

    Science.gov (United States)

    Münster-Müller, S; Scheid, N; Holdermann, T; Schneiders, S; Pütz, M

    2018-05-21

    In this paper results of a pilot study on the profiling of the synthetic cannabinoid receptor agonist 5F-PB-22 (5F-QUPIC, pentylfluoro-1H-indole-3-carboxylic acid-8-quinolinyl ester) via isotope ratio mass spectrometry are presented. It is focused on δ 13 C, δ 15 N and δ 2 H isotope ratios, which are determined using elemental analyser (EA) and high temperature elemental analyser (TC/EA) coupled to an isotope ratio mass spectrometer (IRMS). By means of a sample of pure material of 5F-PB-22 it is shown that the extraction of 5F-PB-22 from herbal material, a rapid clean-up procedure, or preparative column chromatography had no influences on the isotope ratios. Furthermore, 5F-PB-22 was extracted from fourteen different herbal blend samples ("Spice products" from police seizures) and analysed via IRMS, yielding three clusters containing seven, five and two samples, distinguishable through their isotopic composition, respectively. It is assumed that herbal blends in each cluster have been manufactured from individual batches of 5F-PB-22. This article is protected by copyright. All rights reserved.

  3. Liquid and gas chromatography coupled to isotope ratio mass spectrometry for the determination of 13C-valine isotopic ratios in complex biological samples.

    Science.gov (United States)

    Godin, Jean-Philippe; Breuillé, Denis; Obled, Christiane; Papet, Isabelle; Schierbeek, Henk; Hopfgartner, Gérard; Fay, Laurent-Bernard

    2008-10-01

    On-line gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) is commonly used to measure isotopic ratios at natural abundance as well as for tracer studies in nutritional and medical research. However, high-precision (13)C isotopic enrichment can also be measured by liquid chromatography-isotope ratio mass spectrometry (LC-IRMS). Indeed, LC-IRMS can be used, as shown by the new method reported here, to obtain a baseline separation and to measure (13)C isotopic enrichment of underivatised amino acids (Asp, Thr-Ser, Glu, Pro, Gly, Ala, Cys and Val). In case of Val, at natural abundance, the SD(delta(13)C) reported with this method was found to be below 1 per thousand . Another key feature of the new LC-IRMS method reported in this paper is the comparison of the LC-IRMS approach with the conventional GC-C-IRMS determination. To perform this comparative study, isotopic enrichments were measured from underivatised Val and its N(O, S)-ethoxycarbonyl ethyl ester derivative. Between 0.0 and 1.0 molar percent excess (MPE) (delta(13)C= -12.3 to 150.8 per thousand), the calculated root-mean-square (rms) of SD was 0.38 and 0.46 per thousand and the calculated rms of accuracy was 0.023 and 0.005 MPE, respectively, for GC-C-IRMS and LC-IRMS. Both systems measured accurately low isotopic enrichments (0.002 atom percent excess (APE)) with an SD (APE) of 0.0004. To correlate the relative (delta(13)C) and absolute (atom%, APE and MPE) isotopic enrichment of Val measured by the GC-C-IRMS and LC-IRMS devices, mathematical equations showing the slope and intercept of the curves were established and validated with experimental data between 0.0 to 2.3 MPE. Finally, both GC-C-IRMS and LC-IRMS instruments were also used to assess isotopic enrichment of protein-bound (13)C-Val in tibial epiphysis in a tracer study performed in rats. Isotopic enrichments measured by LC-IRMS and GC-C-IRMS were not statistically different (p>0.05). The results of this work indicate that

  4. Validation of SmartRank: A likelihood ratio software for searching national DNA databases with complex DNA profiles.

    Science.gov (United States)

    Benschop, Corina C G; van de Merwe, Linda; de Jong, Jeroen; Vanvooren, Vanessa; Kempenaers, Morgane; Kees van der Beek, C P; Barni, Filippo; Reyes, Eusebio López; Moulin, Léa; Pene, Laurent; Haned, Hinda; Sijen, Titia

    2017-07-01

    Searching a national DNA database with complex and incomplete profiles usually yields very large numbers of possible matches that can present many candidate suspects to be further investigated by the forensic scientist and/or police. Current practice in most forensic laboratories consists of ordering these 'hits' based on the number of matching alleles with the searched profile. Thus, candidate profiles that share the same number of matching alleles are not differentiated and due to the lack of other ranking criteria for the candidate list it may be difficult to discern a true match from the false positives or notice that all candidates are in fact false positives. SmartRank was developed to put forward only relevant candidates and rank them accordingly. The SmartRank software computes a likelihood ratio (LR) for the searched profile and each profile in the DNA database and ranks database entries above a defined LR threshold according to the calculated LR. In this study, we examined for mixed DNA profiles of variable complexity whether the true donors are retrieved, what the number of false positives above an LR threshold is and the ranking position of the true donors. Using 343 mixed DNA profiles over 750 SmartRank searches were performed. In addition, the performance of SmartRank and CODIS were compared regarding DNA database searches and SmartRank was found complementary to CODIS. We also describe the applicable domain of SmartRank and provide guidelines. The SmartRank software is open-source and freely available. Using the best practice guidelines, SmartRank enables obtaining investigative leads in criminal cases lacking a suspect. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Determination of trace element concentrations and stable lead, uranium and thorium isotope ratios by quadrupole-ICP-MS in NORM and NORM-polluted sample leachates

    Energy Technology Data Exchange (ETDEWEB)

    Mas, J.L., E-mail: ppmasb@us.es [Dpto. Fisica Aplicada I, EPS, Universidad de Sevilla, 41012 Sevilla (Spain); Villa, M. [Servicio de Radioisotopos, Centro de Investigacion, Tecnologia e Innovacion (CITIUS), Universidad de Sevilla, Avda. Reina Mercedes 4b, 41012 Sevilla (Spain); Dpto. Fisica Aplicada II, ETS de Arquitectura, Universidad de Sevilla, Avda. Reina Mercedes 2, 41012 Sevilla (Spain); Hurtado, S. [Servicio de Radioisotopos, Centro de Investigacion, Tecnologia e Innovacion (CITIUS), Universidad de Sevilla, Avda. Reina Mercedes 4b, 41012 Sevilla (Spain); Garcia-Tenorio, R. [Dpto. Fisica Aplicada II, ETS de Arquitectura, Universidad de Sevilla, Avda. Reina Mercedes 2, 41012 Sevilla (Spain)

    2012-02-29

    Highlights: Black-Right-Pointing-Pointer Polluted sediment and NORM samples. Black-Right-Pointing-Pointer An efficient yet fast process allowing multi-parametric determinations in <3 days. Black-Right-Pointing-Pointer Trace element concentrations, Pb, Th and U isotope ratios with a single instrument. - Abstract: This work focuses on the monitoring of the potential pollution in scenarios that involve NORM-related industrial activities (environmental or in-door scenarios). The objective was to develop a method to determine extent and origin of the contamination, suitable for monitoring (i.e. simple, fast and economical) and avoiding the use of too many different instruments. It is presented a radiochemical method that allows the determination of trace element concentrations and {sup 206}Pb/{sup 207}Pb/{sup 208}Pb, {sup 238}U/{sup 234}U and {sup 232}Th/{sup 230}Th isotope ratios using a single sample aliquot and a single instrument (ICP-QMS). Eichrom UTEVA{sup Registered-Sign} extraction chromatography minicolumns were used to separate uranium and thorium in sample leachates. Independent ICP-MS determinations of uranium and thorium isotope ratios were carried out afterwards. Previously a small aliquot of the leachate was used for the determination of trace element concentrations and lead isotope ratios. Several radiochemical arrangements were tested to get maximum performances and simplicity of the method. The performances of the method were studied in terms of chemical yields of uranium and thorium and removal of the potentially interfering elements. The established method was applied to samples from a chemical industry and sediments collected in a NORM-polluted scenario. The results obtained from our method allowed us to infer not only the extent, but also the sources of the contamination in the area.

  6. Determination of trace element concentrations and stable lead, uranium and thorium isotope ratios by quadrupole-ICP-MS in NORM and NORM-polluted sample leachates

    International Nuclear Information System (INIS)

    Mas, J.L.; Villa, M.; Hurtado, S.; García-Tenorio, R.

    2012-01-01

    Highlights: ► Polluted sediment and NORM samples. ► An efficient yet fast process allowing multi-parametric determinations in 206 Pb/ 207 Pb/ 208 Pb, 238 U/ 234 U and 232 Th/ 230 Th isotope ratios using a single sample aliquot and a single instrument (ICP-QMS). Eichrom UTEVA ® extraction chromatography minicolumns were used to separate uranium and thorium in sample leachates. Independent ICP-MS determinations of uranium and thorium isotope ratios were carried out afterwards. Previously a small aliquot of the leachate was used for the determination of trace element concentrations and lead isotope ratios. Several radiochemical arrangements were tested to get maximum performances and simplicity of the method. The performances of the method were studied in terms of chemical yields of uranium and thorium and removal of the potentially interfering elements. The established method was applied to samples from a chemical industry and sediments collected in a NORM-polluted scenario. The results obtained from our method allowed us to infer not only the extent, but also the sources of the contamination in the area.

  7. Optimization of on-line hydrogen stable isotope ratio measurements of halogen- and sulfur-bearing organic compounds using elemental analyzer–chromium/high-temperature conversion isotope ratio mass spectrometry (EA-Cr/HTC-IRMS)

    Science.gov (United States)

    Gehre, Matthias; Renpenning, Julian; Geilmann, Heike; Qi, Haiping; Coplen, Tyler B.; Kümmel, Steffen; Ivdra, Natalija; Brand, Willi A.; Schimmelmann, Arndt

    2017-01-01

    Rationale: Accurate hydrogen isotopic analysis of halogen- and sulfur-bearing organics has not been possible with traditional high-temperature conversion (HTC) because the formation of hydrogen-bearing reaction products other than molecular hydrogen (H2) is responsible for non-quantitative H2 yields and possible hydrogen isotopic fractionation. Our previously introduced, new chromium-based EA-Cr/HTC-IRMS (Elemental Analyzer–Chromium/High-Temperature Conversion Isotope Ratio Mass Spectrometry) technique focused primarily on nitrogen-bearing compounds. Several technical and analytical issues concerning halogen- and sulfur-bearing samples, however, remained unresolved and required further refinement of the reactor systems.

  8. Identification of Bottled Zam Zam Water in Malaysian Market using Hydrogen and Oxygen Stable Isotobe Ratios (δ2H and δ18O)

    International Nuclear Information System (INIS)

    Roslanzairi Mostapa; Abdul Kadir Ishak; Kamaruzaman Mohamad; Rohaimah Demanah

    2014-01-01

    The water drawn from the well of Zam Zam is believed by the adherents of Islam to be blessed and capable of treating a variety of ailments. The water originates from a well in an alluvium area, located in Mecca, Saudi Arabia and has been in use since 4000 years ago. Due to the religious significance of the water drawn from this well, bottled versions are very popular among Malaysians. Unfortunately, this disproportionate popularity may entice some unscrupulous dealers to engage in fraudulent behaviour, such as selling ordinary water purported to be Zam Zam water. This unethical practice might very well pose a physical and economical hazard to consumers. Therefore, for the purpose of this preliminary study, five samples of Zam Zam bottled water from different brands were purchased and analyzed using Isotope Ratio Mass Spectrometer (IRMS). For comparison purpose, four samples of zam zam water from Mecca, and two more types of water samples originating from Malaysian were also analyzed, namely, bottled drinking water and tap water. The sources of these water samples are from groundwater and surface water (river), respectively. Results of hydrogen (ε 2 H) and oxygen (ε 18 O) isotope ratios of zam zam water from mecca are in the range of -13.62 % to -10.60 %, and -2.17 % to 0.06 %, respectively, while the hydrogen (ε 2 H) and oxygen (δ 18 O) isotope ratios of five samples from the bottled Zam Zam water are within the range of -50.74 % to -7.95 % to -5.39 %, respectively. The results from the measured values of all the water samples, and might be immensely useful for the purpose of regulatory monitoring of bottled water products. (author)

  9. The Net Stable Funding Ratio and banks� participation in monetary policy operations: some evidence for the euro area

    OpenAIRE

    Antonio Scalia; Sergio Longoni; Tiziana Rosolin

    2013-01-01

    Based on a review of the analytical underpinnings of the effects of the NSFR on banks� choices, this paper attempts to relate banks� strategies to developments in the value of the ratio in the euro area. In spite of a not-so-near implementation date, the evidence is that the NSFR already matters for banks� choices, and it might be more relevant as a decision variable than alternative leverage indicators. As part of a convergence process towards the 100 per cent threshold, we estimate th...

  10. Microbial enterotypes, inferred by the prevotella-to-bacteroides ratio, remained stable during a 6-month randomized controlled diet intervention with the new nordic diet

    DEFF Research Database (Denmark)

    Roager, Henrik Munch; Licht, Tine Rask; Poulsen, Sanne

    2014-01-01

    It has been suggested that the human gut microbiota can be divided into enterotypes based on the abundance of specific bacterial groups; however, the biological significance and stability of these enterotypes remain unresolved. Here, we demonstrated that subjects (n = 62) 18 to 65 years old......, controlled dietary intervention, where the effect of consuming a diet in accord with the new Nordic diet (NND) recommendations as opposed to consuming the average Danish diet (ADD) on the gut microbiota was investigated. In this study, subjects (with and without stratification according to P/B ratio) did...

  11. Dissolved organic carbon, CO2, and CH4 concentrations and their stable isotope ratios in thermokarst lakes on the Qinghai-Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    Cuicui Mu

    2016-01-01

    Full Text Available Thermokarst lakes are widely distributed on the Qinghai-Tibetan Plateau (QTP, which accounts for 8% of the global permafrost area. These lakes probably promote organic matter biodegradation and thus accelerate the emission of carbon-based greenhouse gases. However, little is known about greenhouse gas concentrations and their stable isotopes characteristics of these lakes. In this study, we measured the concentrations of dissolved organic carbon (DOC, dissolved CO2 and CH4, as well as the distribution of δ13CCO2, δ13CCH4, and δ13COM (organic matter of lake sediments in thermokarst lakes on the QTP. Results showed that the OM of the lake sediments was highly decomposed. The concentrations of DOC, CO2 and CH4 in the lake water on the QTP were 1.2–49.6 mg L–1, 3.6–45.0 μmol L–1 and 0.28–3.0 μmol L–1, respectively. The highest CO2 and CH4 concentrations were recorded in July while the lowest values in September, which suggested that temperature had an effect on greenhouse gas production, although this pattern may also relate to thermal stratification of the water column. The results implied that thermokast lakes should be paid more attention to regarding carbon cycle and greenhouse gas emissions on the QTP.

  12. A new method for precise determination of iron, zinc and cadmium stable isotope ratios in seawater by double-spike mass spectrometry.

    Science.gov (United States)

    Conway, Tim M; Rosenberg, Angela D; Adkins, Jess F; John, Seth G

    2013-09-02

    The study of Fe, Zn and Cd stable isotopes (δ(56)Fe, δ(66)Zn and δ(114)Cd) in seawater is a new field, which promises to elucidate the marine cycling of these bioactive trace metals. However, the analytical challenges posed by the low concentration of these metals in seawater has meant that previous studies have typically required large sample volumes, highly limiting data collection in the oceans. Here, we present the first simultaneous method for the determination of these three isotope systems in seawater, using Nobias PA-1 chelating resin to extract metals from seawater, purification by anion exchange chromatography, and analysis by double spike MC-ICPMS. This method is designed for use on only a single litre of seawater and has blanks of 0.3, 0.06 and <0.03 ng for Fe, Zn and Cd respectively, representing a 1-20 fold reduction in sample size and a 4-130 decrease in blank compared to previously reported methods. The procedure yields data with high precision for all three elements (typically 0.02-0.2‰; 1σ internal precision), allowing us to distinguish natural variability in the oceans, which spans 1-3‰ for all three isotope systems. Simultaneous extraction and purification of three metals makes this method ideal for high-resolution, large-scale endeavours such as the GEOTRACES program. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Developmental and spatial variations in the diet signatures of hyperbenthic shrimp Nauticaris marionis at the Prince Edward Islands based on stable isotope ratios and fatty acid profiles

    Science.gov (United States)

    Richoux, Nicole B.; Allan, E. Louise; Froneman, P. William

    2016-04-01

    The caridean shrimp Nauticaris marionis is an ecologically important species in the benthic community around the sub-Antarctic Prince Edward Islands (PEI) as it represents a key prey item for a variety of top predators breeding on the islands. We hypothesized that the diet of N. marionis shifts during its development, and that spatial variability in food availability results in differentiation in the diet signatures of specimens collected from various locations of the shelf waters around the PEI. Specimens were collected from nine stations (depth range 70 to 240 m) around the PEI at inter-island shelf (from west to east: upstream, between and downstream) and nearshore regions during austral autumn 2009. Stable isotope and fatty acid data both revealed spatial and developmental variations in the shrimp diet. Nearshore shrimp were more 13C-enriched than those from the inter-island region, suggesting increased kelp detritus entered the food web in the nearshore regions. The shrimp showed increases in δ13C and δ15N signatures (and trophic position) with an increase in body size, resulting in distinctions between size classes that reflected shifts in their trophic niche through development. The fatty acid profiles similarly indicated distinctions in diet with increased shrimp size (in the deep regions), and spatial variability was evident in relation to region and depth. All shrimp contained large proportions of polyunsaturated and essential fatty acids, indicating that the quality of food consumed was similar between regions despite the diet variability. Our results provide new dietary information about a key species operating near the base of the food web at the highly productive PEI, and show that there were no areas of enhanced nutrition available to the shrimp. As such, there was no nutritional advantage to shrimp inhabiting any specific region around the PEI.

  14. Spring-Summer Temperatures Since AD 1780 Reconstructed from Stable Oxygen Isotope Ratios in White Spruce Tree-Rings from the Mackenzie Delta, Northwestern Canada

    Science.gov (United States)

    Porter, Trevor J.; Pisaric, Michael F. J.; Field, Robert D.; Kokelj, Steven V.; Edwards, Thomas W. D.; deMontigny, Peter; Healy, Richard; LeGrande, Allegra N.

    2013-01-01

    High-latitude delta(exp 18)O archives deriving from meteoric water (e.g., tree-rings and ice-cores) can provide valuable information on past temperature variability, but stationarity of temperature signals in these archives depends on the stability of moisture source/trajectory and precipitation seasonality, both of which can be affected by atmospheric circulation changes. A tree-ring delta(exp 18)O record (AD 1780-2003) from the Mackenzie Delta is evaluated as a temperature proxy based on linear regression diagnostics. The primary source of moisture for this region is the North Pacific and, thus, North Pacific atmospheric circulation variability could potentially affect the tree-ring delta(exp 18)O-temperature signal. Over the instrumental period (AD 1892-2003), tree-ring delta(exp 18)O explained 29% of interannual variability in April-July minimum temperatures, and the explained variability increases substantially at lower-frequencies. A split-period calibration/verification analysis found the delta(exp 18)O-temperature relation was time-stable, which supported a temperature reconstruction back to AD 1780. The stability of the delta(exp 18)O-temperature signal indirectly implies the study region is insensitive to North Pacific circulation effects, since North Pacific circulation was not constant over the calibration period. Simulations from the NASA-GISS ModelE isotope-enabled general circulation model confirm that meteoric delta(exp 18)O and precipitation seasonality in the study region are likely insensitive to North Pacific circulation effects, highlighting the paleoclimatic value of tree-ring and possibly other delta(exp 18)O records from this region. Our delta(exp 18)O-based temperature reconstruction is the first of its kind in northwestern North America, and one of few worldwide, and provides a long-term context for evaluating recent climate warming in the Mackenzie Delta region.

  15. The Prestudy for Studying Inorganic Nutrient Metabolism in Humans : the Aplication of ICP-MS for Determination of Stable Isotope Ratio of Fe and Zn

    International Nuclear Information System (INIS)

    Rukihati; Sumadjo

    2001-01-01

    A method is described for the determination of isotope ratio of Fe and Zn by means of inductively coupled plasma-mass spectrometry (ICP-MS). The mass spectrometer was operated in low resolution mode to provide maximal sensitivity. Typical conditions for operations were: plasma power 0.85 k W, reflected power 56 Fe/ 54 Fe, 57 Fe/ 54 Fe, 58 Fe/ 54 Fe, dan 64 Zn/ 67 Zn, 66 Zn/ 67 Zn, 68 Zn/ 67 Zn, 70 Zn/ 67 Zn measured by ICP-MS showed a good level of agreement with TIMS (thermal ionization mass spectrometry). This method was prepared for studying the absorption and/or metabolism of inorganic nutrients in humans. (author)

  16. Increase in soil stable carbon isotope ratio relates to loss of organic carbon: results from five long-term bare fallow experiments

    DEFF Research Database (Denmark)

    Menichetti, Lorenzo; Houot, Sabine; van Oort, Folkert

    2015-01-01

    Changes in the 12C/13C ratio (expressed as δ13C) of soil organic C (SOC) has been observed over long time scales and with depth in soil profiles. The changes are ascribed to the different reaction kinetics of 12C and 13C isotopes and the different isotopic composition of various SOC pool components...... examined. The overall estimate of the fractionation coefficient (ε) was −1.2 ± 0.3 ‰. This coefficient represents an important input to studies of long-term SOC dynamics in agricultural soils that are based on variations in 13C natural abundance. The variance of ε may be ascribed to site characteristics...... some impact on isotope abundance and fractionation....

  17. Combination of sugar analysis and stable isotope ratio mass spectrometry to detect the use of artificial sugars in royal jelly production.

    Science.gov (United States)

    Wytrychowski, Marine; Daniele, Gaëlle; Casabianca, Hervé

    2012-05-01

    The effects of feeding bees artificial sugars and/or proteins on the sugar compositions and (13)C isotopic measurements of royal jellies (RJs) were evaluated. The sugars fed to the bees were two C4 sugars (cane sugar and maize hydrolysate), two C3 sugars (sugar beet, cereal starch hydrolysate), and honey. The proteins fed to them were pollen, soybean, and yeast powder proteins. To evaluate the influence of the sugar and/or protein feeding over time, samples were collected during six consecutive harvests. (13)C isotopic ratio measurements of natural RJs gave values of around -25 ‰, which were also seen for RJs obtained when the bees were fed honey or C3 sugars. However, the RJs obtained when the bees were fed cane sugar or corn hydrolysate (regardless of whether they were also fed proteins) gave values of up to -17 ‰. Sugar content analysis revealed that the composition of maltose, maltotriose, sucrose, and erlose varied significantly over time in accordance with the composition of the syrup fed to the bees. When corn and cereal starch hydrolysates were fed to the bees, the maltose and maltotriose contents of the RJs increased up to 5.0 and 1.3 %, respectively, compared to the levels seen in authentic samples (i.e., samples obtained when the bees were fed natural food: honey and pollen) that were inferior to 0.2% and not detected, respectively. The sucrose and erlose contents of natural RJs were around 0.2 %, whereas those in RJs obtained when the bees were fed cane or beet sugar were as much as 4.0 and 1.3 %, respectively. The combination of sugar analysis and (13)C isotopic ratio measurements represents a very efficient analytical methodology for detecting (from early harvests onward) the use of C4 and C3 artificial sugars in the production of RJ.

  18. Synthesis and structure determination of a stable organometallic uranium(V) imine complex and its isolobal anionic U(IV)-ate complex

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, M.; Botoshanskii, M.; Eisen, M.S. [Schulich Faculty of Chemistry, and Institute of Catalysis Science and Technology, Technion Israel Institute of Technology, Haifa (Israel); Bannenberg, Th.; Tamm, M. [Institut fur Anorganische und Analytische Chemie, Technische Universitat Braunschweig (Germany)

    2010-06-15

    The reaction of one equivalent of Cp*{sub 2}UCl{sub 2} with 2-(trimethylsilyl-imino)-1,3-di-tert-butyl-imidazoline in boiling toluene afforded a one electron oxidation of the uranium metal and the opening of the N-heterocyclic ring, resulting in the formation of an organometallic uranium(V) imine complex. This complex crystallized with one molecule of toluene in the unit cell, and its solid-state structure was determined by X-ray diffraction analysis. When the same reaction was performed in perdeuterated toluene, a myriad of organometallic complexes were obtained, however, when equimolar amounts of water were used in toluene, the same complex was obtained, and its solid state characterization shows two independent molecules in the unit cell with an additional water molecule. For comparison of the geometric parameters, the corresponding isolobal anionic uranium(IV) complex [Cp*{sub 2}UCl{sub 3}]{sup -} was synthesized by the reaction of Cp*{sub 2}UCl{sub 2} with 1,3-di-tert-butyl-imidazolium chloride, and the resulting U(IV)-ate complex was characterized by X-ray diffraction analysis. (authors)

  19. Highly Chemo- and Stereoselective Transfer Semihydrogenation of Alkynes Catalyzed by a Stable, Well-defined Manganese(II) Complex

    KAUST Repository

    Brzozowska, Aleksandra; Azofra, Luis Miguel; Zubar, Viktoriia; Atodiresei, Iuliana; Cavallo, Luigi; Rueping, Magnus; El-Sepelgy, Osama

    2018-01-01

    The first example of manganese catalyzed semihydrogenation of internal alkynes to (Z)-alkenes using ammonia borane as a hydrogen donor is reported. The reaction is catalyzed by a pincer complex of the earth abundant manganese(II) salt in the absence of any additives, base or super hydride. The ammonia borane smoothly reduces the manganese pre-catalyst [Mn(II)-PNP][Cl]2 to the catalytically active species [Mn(I)-PNP]-hydride in the triplet spin state. This manganese hydride is highly stabilized by complexation with the alkyne substrate. Computational DFT analysis studies of the reaction mechanism rationalizes the origin of stereoselectivity towards formation of (Z)-alkenes.

  20. Highly Chemo- and Stereoselective Transfer Semihydrogenation of Alkynes Catalyzed by a Stable, Well-defined Manganese(II) Complex

    KAUST Repository

    Brzozowska, Aleksandra

    2018-03-30

    The first example of manganese catalyzed semihydrogenation of internal alkynes to (Z)-alkenes using ammonia borane as a hydrogen donor is reported. The reaction is catalyzed by a pincer complex of the earth abundant manganese(II) salt in the absence of any additives, base or super hydride. The ammonia borane smoothly reduces the manganese pre-catalyst [Mn(II)-PNP][Cl]2 to the catalytically active species [Mn(I)-PNP]-hydride in the triplet spin state. This manganese hydride is highly stabilized by complexation with the alkyne substrate. Computational DFT analysis studies of the reaction mechanism rationalizes the origin of stereoselectivity towards formation of (Z)-alkenes.

  1. Stable isotope ratios in swale sequences of Lake Superior as indicators of climate and lake level fluctuations during the Late Holocene

    Science.gov (United States)

    Sharma, Shruti; Mora, G.; Johnston, J.W.; Thompson, T.A.

    2005-01-01

    Beach ridges along the coastline of Lake Superior provide a long-term and detailed record of lake level fluctuations for the past 4000 cal BP. Although climate change has been invoked to explain these fluctuations, its role is still in debate. Here, we reconstruct water balance by employing peat samples collected from swale deposits present between beach ridge sequences at two locations along the coastline of Lake Superior. Carbon isotope ratios for Sphagnum remains from these peat deposits are used as a proxy for water balance because the presence or absence of water films on Sphagnum controls the overall isotope discrimination effects. Consequently, increased average water content in Sphagnum produces elevated ??13C values. Two maxima of Sphagnum ??13C values interpreted to reflect wetter conditions prevailed from 3400 to 2400 cal BP and from about 1900 to 1400 cal BP. There are two relatively short drier periods as inferred from low Sphagnum ??13C values: one is centered at about 2300 cal BP, and one begins at 1400 cal BP. A good covariance was found between Sphagnum ??13C values and reconstructed lake-levels for Lake Michigan in which elevated carbon isotope values correlate well with higher lake levels. Based on this covariance, we conclude that climate exerts a strong influence on lake levels in Lake Superior for the past 4000 cal BP. ?? 2005 Elsevier Ltd. All rights reserved.

  2. A critical examination of the possible application of zinc stable isotope ratios in bivalve mollusks and suspended particulate matter to trace zinc pollution in a tropical estuary.

    Science.gov (United States)

    Araújo, Daniel; Machado, Wilson; Weiss, Dominik; Mulholland, Daniel S; Boaventura, Geraldo R; Viers, Jerome; Garnier, Jeremie; Dantas, Elton L; Babinski, Marly

    2017-07-01

    The application of zinc (Zn) isotopes in bivalve tissues to identify zinc sources in estuaries was critically assessed. We determined the zinc isotope composition of mollusks (Crassostrea brasiliana and Perna perna) and suspended particulate matter (SPM) in a tropical estuary (Sepetiba Bay, Brazil) historically impacted by metallurgical activities. The zinc isotope systematics of the SPM was in line with mixing of zinc derived from fluvial material and from metallurgical activities. In contrast, source mixing alone cannot account for the isotope ratios observed in the bivalves, which are significantly lighter in the contaminated metallurgical zone (δ 66 Zn JMC  = +0.49 ± 0.06‰, 2σ, n = 3) compared to sampling locations outside (δ 66 Zn JMC  = +0.83 ± 0.10‰, 2σ, n = 22). This observation suggests that additional factors such as speciation, bioavailability and bioaccumulation pathways (via solution or particulate matter) influence the zinc isotope composition of bivalves. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Use of compound-specific stable carbon isotope ratio measurements of asphaltene-bound polycyclic aromatic hydrocarbons (PAHs) as a novel aid to source apportionment of environmental PAHs

    Energy Technology Data Exchange (ETDEWEB)

    C. Sun; C. Snape; M. Cooper; W. Ivwurie [University of Nottingham, Nottingham (United Kingdom). Nottingham Energy & Fuel Centre

    2005-07-01

    In this study, the PAHs from hydropyrolysis of asphaltenes from different primary sources (e.g. crude oil, low and high temperature coal tars) were characterized by their molecular distributions and {sup 13}C/{sup 12}C isotope ratios. It was found that for all oil samples, the molecular and isotopic profiles for their asphaltene-derived PAHs are both similar to those observed for their contained free aromatics, with {sup 13}C-isotopic values varying from -25 to -27{per_thousand} for the Nigerian and -27 to -30{per_thousand} for North Sea oil samples. For low and high temperature coal tar samples, however, similar molecular but different isotopic profiles were observed for their asphaltene-bound PAHs. The free aromatics are significantly isotopically lighter (by nearly -3{per_thousand}) than their asphaltene-derived counterparts having isotopic values typically between -22 and -23{per_thousand} for all coal tar samples examined, and this leads to a larger isotopic difference of up to 7{per_thousand} between the two sources of PAHs than that already observed between their free aromatics (3{per_thousand}). Applying these results to samples previously examined in an area where unambiguous source apportionment could not be conducted for the PAHs due to likely biodegradation, it was found that the bound PAHs released from the asphaltenes recovered from the soil samples in this area are extremely similar to low temperature tar as the source, in terms of their both molecular (highly alkylated) and isotopic profiles. The free PAHs are much less alkyl substituted confirming that the aromatics detected in this area have been subjected to intensiveenvironmental degradation with alkylated aromatic constituents being preferentially removed from their initial matrix.

  4. Optimization of on-line hydrogen stable isotope ratio measurements of halogen- and sulfur-bearing organic compounds using elemental analyzer-chromium/high-temperature conversion isotope ratio mass spectrometry (EA-Cr/HTC-IRMS).

    Science.gov (United States)

    Gehre, Matthias; Renpenning, Julian; Geilmann, Heike; Qi, Haiping; Coplen, Tyler B; Kümmel, Steffen; Ivdra, Natalija; Brand, Willi A; Schimmelmann, Arndt

    2017-03-30

    Accurate hydrogen isotopic analysis of halogen- and sulfur-bearing organics has not been possible with traditional high-temperature conversion (HTC) because the formation of hydrogen-bearing reaction products other than molecular hydrogen (H 2 ) is responsible for non-quantitative H 2 yields and possible hydrogen isotopic fractionation. Our previously introduced, new chromium-based EA-Cr/HTC-IRMS (Elemental Analyzer-Chromium/High-Temperature Conversion Isotope Ratio Mass Spectrometry) technique focused primarily on nitrogen-bearing compounds. Several technical and analytical issues concerning halogen- and sulfur-bearing samples, however, remained unresolved and required further refinement of the reactor systems. The EA-Cr/HTC reactor was substantially modified for the conversion of halogen- and sulfur-bearing samples. The performance of the novel conversion setup for solid and liquid samples was monitored and optimized using a simultaneously operating dual-detection system of IRMS and ion trap MS. The method with several variants in the reactor, including the addition of manganese metal chips, was evaluated in three laboratories using EA-Cr/HTC-IRMS (on-line method) and compared with traditional uranium-reduction-based conversion combined with manual dual-inlet IRMS analysis (off-line method) in one laboratory. The modified EA-Cr/HTC reactor setup showed an overall H 2 -recovery of more than 96% for all halogen- and sulfur-bearing organic compounds. All results were successfully normalized via two-point calibration with VSMOW-SLAP reference waters. Precise and accurate hydrogen isotopic analysis was achieved for a variety of organics containing F-, Cl-, Br-, I-, and S-bearing heteroelements. The robust nature of the on-line EA-Cr/HTC technique was demonstrated by a series of 196 consecutive measurements with a single reactor filling. The optimized EA-Cr/HTC reactor design can be implemented in existing analytical equipment using commercially available material and

  5. Fermat's principle and the formal equivalence of local light-ray rotation and refraction at the interface between homogeneous media with a complex refractive index ratio.

    Science.gov (United States)

    Sundar, Bhuvanesh; Hamilton, Alasdair C; Courtial, Johannes

    2009-02-01

    We derive a formal description of local light-ray rotation in terms of complex refractive indices. We show that Fermat's principle holds, and we derive an extended Snell's law. The change in the angle of a light ray with respect to the normal of a refractive index interface is described by the modulus of the refractive index ratio; the rotation around the interface normal is described by the argument of the refractive index ratio.

  6. A thermogravimetric analysis (TGA) method developed for estimating the stoichiometric ratio of solid-state {alpha}-cyclodextrin-based inclusion complexes

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Yuxiang; Wang, Jinpeng; Bashari, Mohanad; Hu, Xiuting [The State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122 (China); Feng, Tao [School of Perfume and Aroma Technology, Shanghai Institute of Technology, Shanghai 201418 (China); Xu, Xueming [The State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122 (China); Jin, Zhengyu, E-mail: jinlab2008@yahoo.com [The State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122 (China); Tian, Yaoqi, E-mail: yqtian@jiangnan.edu.cn [The State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122 (China)

    2012-08-10

    Highlights: Black-Right-Pointing-Pointer We develop a TGA method for the measurement of the stoichiometric ratio. Black-Right-Pointing-Pointer A series of formulas are deduced to calculate the stoichiometric ratio. Black-Right-Pointing-Pointer Four {alpha}-CD-based inclusion complexes were successfully prepared. Black-Right-Pointing-Pointer The developed method is applicable. - Abstract: An approach mainly based on thermogravimetric analysis (TGA) was developed to evaluate the stoichiometric ratio (SR, guest to host) of the guest-{alpha}-cyclodextrin (Guest-{alpha}-CD) inclusion complexes (4-cresol-{alpha}-CD, benzyl alcohol-{alpha}-CD, ferrocene-{alpha}-CD and decanoic acid-{alpha}-CD). The present data obtained from Fourier transform-infrared (FT-IR) spectroscopy showed that all the {alpha}-CD-based inclusion complexes were successfully prepared in a solid-state form. The stoichiometric ratios of {alpha}-CD to the relative guests (4-cresol, benzyl alcohol, ferrocene and decanoic acid) determined by the developed method were 1:1, 1:2, 2:1 and 1:2, respectively. These SR data were well demonstrated by the previously reported X-ray diffraction (XRD) method and the NMR confirmatory experiments, except the SR of decanoic acid with a larger size and longer chain was not consistent. It is, therefore, suggested that the TGA-based method is applicable to follow the stoichiometric ratio of the polycrystalline {alpha}-CD-based inclusion complexes with smaller and shorter chain guests.

  7. A thermogravimetric analysis (TGA) method developed for estimating the stoichiometric ratio of solid-state α-cyclodextrin-based inclusion complexes

    International Nuclear Information System (INIS)

    Bai, Yuxiang; Wang, Jinpeng; Bashari, Mohanad; Hu, Xiuting; Feng, Tao; Xu, Xueming; Jin, Zhengyu; Tian, Yaoqi

    2012-01-01

    Highlights: ► We develop a TGA method for the measurement of the stoichiometric ratio. ► A series of formulas are deduced to calculate the stoichiometric ratio. ► Four α-CD-based inclusion complexes were successfully prepared. ► The developed method is applicable. - Abstract: An approach mainly based on thermogravimetric analysis (TGA) was developed to evaluate the stoichiometric ratio (SR, guest to host) of the guest–α-cyclodextrin (Guest-α-CD) inclusion complexes (4-cresol-α-CD, benzyl alcohol-α-CD, ferrocene-α-CD and decanoic acid-α-CD). The present data obtained from Fourier transform-infrared (FT-IR) spectroscopy showed that all the α-CD-based inclusion complexes were successfully prepared in a solid-state form. The stoichiometric ratios of α-CD to the relative guests (4-cresol, benzyl alcohol, ferrocene and decanoic acid) determined by the developed method were 1:1, 1:2, 2:1 and 1:2, respectively. These SR data were well demonstrated by the previously reported X-ray diffraction (XRD) method and the NMR confirmatory experiments, except the SR of decanoic acid with a larger size and longer chain was not consistent. It is, therefore, suggested that the TGA-based method is applicable to follow the stoichiometric ratio of the polycrystalline α-CD-based inclusion complexes with smaller and shorter chain guests.

  8. Increasing volume and complexity of pediatric epilepsy surgery with stable seizure outcome between 2008 and 2014: A nationwide multicenter study.

    Science.gov (United States)

    Barba, Carmen; Specchio, Nicola; Guerrini, Renzo; Tassi, Laura; De Masi, Salvatore; Cardinale, Francesco; Pellacani, Simona; De Palma, Luca; Battaglia, Domenica; Tamburrini, Gianpiero; Didato, Giuseppe; Freri, Elena; Consales, Alessandro; Nozza, Paolo; Zamponi, Nelia; Cesaroni, Elisabetta; Di Gennaro, Giancarlo; Esposito, Vincenzo; Giulioni, Marco; Tinuper, Paolo; Colicchio, Gabriella; Rocchi, Raffaele; Rubboli, Guido; Giordano, Flavio; Lo Russo, Giorgio; Marras, Carlo Efisio; Cossu, Massimo

    2017-10-01

    The objective of the study was to assess common practice in pediatric epilepsy surgery in Italy between 2008 and 2014. A survey was conducted among nine Italian epilepsy surgery centers to collect information on presurgical and postsurgical evaluation protocols, volumes and types of surgical interventions, and etiologies and seizure outcomes in pediatric epilepsy surgery between 2008 and 2014. Retrospective data on 527 surgical procedures were collected. The most frequent surgical approaches were temporal lobe resections and disconnections (133, 25.2%) and extratemporal lesionectomies (128, 24.3%); the most frequent etiologies were FCD II (107, 20.3%) and glioneuronal tumors (105, 19.9%). Volumes of surgeries increased over time independently from the age at surgery and the epilepsy surgery center. Engel class I was achieved in 73.6% of patients (range: 54.8 to 91.7%), with no significant changes between 2008 and 2014. Univariate analyses showed a decrease in the proportion of temporal resections and tumors and an increase in the proportion of FCDII, while multivariate analyses revealed an increase in the proportion of extratemporal surgeries over time. A higher proportion of temporal surgeries and tumors and a lower proportion of extratemporal and multilobar surgeries and of FCD were observed in low (epilepsy surgery in Italy between 2008 and 2014, associated with a stable seizure outcome. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. ATP forms a stable complex with the essential histidine kinase WalK (YycG) domain

    Energy Technology Data Exchange (ETDEWEB)

    Celikel, Reha; Veldore, Vidya Harini [University of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, AR 72205 (United States); Mathews, Irimpan [Stanford Synchrotron Radiation Lightsource, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Devine, Kevin M., E-mail: kdevine@tcd.ie [Trinity College Dublin, Dublin 2 (Ireland); Varughese, Kottayil I., E-mail: kdevine@tcd.ie [University of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, AR 72205 (United States)

    2012-07-01

    The histidine WalK (YycG) plays a crucial role in coordinating murein synthesis with cell division and the crystal structure of its ATP binding domain has been determined. Interestingly the bound ATP was not hydrolyzed during crystallization and remains intact in the crystal lattice. In Bacillus subtilis, the WalRK (YycFG) two-component system coordinates murein synthesis with cell division. It regulates the expression of autolysins that function in cell-wall remodeling and of proteins that modulate autolysin activity. The transcription factor WalR is activated upon phosphorylation by the histidine kinase WalK, a multi-domain homodimer. It autophosphorylates one of its histidine residues by transferring the γ-phosphate from ATP bound to its ATP-binding domain. Here, the high-resolution crystal structure of the ATP-binding domain of WalK in complex with ATP is presented at 1.61 Å resolution. The bound ATP remains intact in the crystal lattice. It appears that the strong binding interactions and the nature of the binding pocket contribute to its stability. The triphosphate moiety of ATP wraps around an Mg{sup 2+} ion, providing three O atoms for coordination in a near-ideal octahedral geometry. The ATP molecule also makes strong interactions with the protein. In addition, there is a short contact between the exocyclic O3′ of the sugar ring and O2B of the β-phosphate, implying an internal hydrogen bond. The stability of the WalK–ATP complex in the crystal lattice suggests that such a complex may exist in vivo poised for initiation of signal transmission. This feature may therefore be part of the sensing mechanism by which the WalRK two-component system is so rapidly activated when cells encounter conditions conducive for growth.

  10. Highly efficient and stable cyclometalated ruthenium(II) complexes as sensitizers for dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Huang, Jian-Feng; Liu, Jun-Min; Su, Pei-Yang; Chen, Yi-Fan; Shen, Yong; Xiao, Li-Min; Kuang, Dai-Bin; Su, Cheng-Yong

    2015-01-01

    Highlights: • Four novel thiocyanate-free cyclometalated ruthenium sensitizer were conveniently synthesized. • The D-CF 3 -sensitized DSSCs show higher efficiency compared to N719 based cells. • The DSSCs based on D-CF 3 and D-bisCF 3 sensitizers exhibit excellent long-term stability. • The diverse cyclometalated Ru complexes can be developed as high-performance sensitizers for use in DSSC. - Abstract: Four novel thiocyanate-free cyclometallted Ru(II) complexes, D-bisCF 3 , D-CF 3 , D-OMe, and D-DPA, with two 4,4′-dicarboxylic acid-2,2′-bipyridine together with a functionalized phenylpyridine ancillary ligand, have been designed and synthesized. The effect of different substituents (R = bisCF 3 , CF 3 , OMe, and DPA) on the ancillary C^N ligand on the photophysical properties and photovoltaic performance is investigated. Under standard global AM 1.5 solar conditions, the device based on D-CF 3 sensitizer gives a higher conversion efficiency of 8.74% than those based on D-bisCF 3 , D-OMe, and D-DPA, which can be ascribed to its broad range of visible light absorption, appropriate localization of the frontier orbitals, weak hydrogen bonds between -CF 3 and -OH groups at the TiO 2 surface, moderate dye loading on TiO 2 , and high charge collection efficiency. Moreover, the D-bisCF 3 and D-CF 3 based DSSCs exhibit good stability under 100 mW cm −2 light soaking at 60 °C for 400 h

  11. Synthesis and characterization of a stable humic-urease complex: application to barley seed encapsulation for improving N uptake.

    Science.gov (United States)

    Mvila, Beaufray G; Pilar-Izquierdo, María C; Busto, María D; Perez-Mateos, Manuel; Ortega, Natividad

    2016-07-01

    Most N fertilizers added to soil are not efficiently used by plants and are lost to the atmosphere or leached from the soil, causing environmental pollution and increasing cost. Barley seed encapsulation in calcium alginate gels containing free or immobilized urease to enhance plant utilization of soil N was investigated. Urease was immobilized with soil humic acids (HA). A central composite face-centered design was applied to optimize the immobilization process, reaching an immobilization yield of 127%. Soil stability of urease was enhanced after the immobilization. Seed encapsulation with free urease (FU) and humic-urease complex (HUC) resulted in a urease activity retention in the coating layer of 46% and 24%, and in germination rates of 87% and 92%, respectively. Under pot culture conditions, the pots planted with seeds encapsulated with FU and HUC showed higher ammonium N (NH4 (+) -N) (26% and 64%, respectively) than the control soil at 28 days after planting (DAP). Moreover, the seed encapsulation with FU and HUC increased the N uptake 83% and 97%, respectively, at 35 DAP. Seed encapsulation with urease could substantially contribute to enhancing plant N nutrition in the early stages of seedling establishment. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  12. Randomized controlled trial of changes in dietary carbohydrate/fat ratio and simple vs complex carbohydrates on body weight and blood lipids: the CARMEN study. The Carbohydrate Ratio Management in European National diets.

    Science.gov (United States)

    Saris, W H; Astrup, A; Prentice, A M; Zunft, H J; Formiguera, X; Verboeket-van de Venne, W P; Raben, A; Poppitt, S D; Seppelt, B; Johnston, S; Vasilaras, T H; Keogh, G F

    2000-10-01

    To investigate the long-term effects of changes in dietary carbohydrate/fat ratio and simple vs complex carbohydrates. Randomized controlled multicentre trial (CARMEN), in which subjects were allocated for 6 months either to a seasonal control group (no intervention) or to one of three experimental groups: a control diet group (dietary intervention typical of the average national intake); a low-fat high simple carbohydrate group; or a low-fat high complex carbohydrate group. Three hundred and ninety eight moderately obese adults. The change in body weight was the primary outcome; changes in body composition and blood lipids were secondary outcomes. Body weight loss in the low-fat high simple carbohydrate and low-fat high complex carbohydrate groups was 0.9 kg (P Fat mass changed by -1.3kg (Plow-fat high simple carbohydrate, low-fat high complex carbohydrate and control diet groups, respectively. Changes in blood lipids did not differ significantly between the dietary treatment groups. Our findings suggest that reduction of fat intake results in a modest but significant reduction in body weight and body fatness. The concomitant increase in either simple or complex carbohydrates did not indicate significant differences in weight change. No adverse effects on blood lipids were observed. These findings underline the importance of this dietary change and its potential impact on the public health implications of obesity.

  13. Investigations of the ratios of stable carbon isotopes in atmospheric relevant VOC using simulation and field experiments; Untersuchungen der Verhaeltnisse stabiler Kohlenstoffisotope in atmosphaerisch relevanten VOC in Simulations- und Feldexperimenten

    Energy Technology Data Exchange (ETDEWEB)

    Spahn, Holger

    2010-07-01

    Volatile organic compounds (VOC) play an important role in the regional and global atmospheric chemistry. The author of the contribution under consideration reports on the analysis of the ratios of stable carbon isotopes ({delta}({sup 13}C) analysis) in atmospheric VOCs. At first, the state of the art of this analytical technique is described. For the first time {delta}({sup 13}C) values of different monoterpenes have been determined in the investigation of vegetable emissions at a plant chamber. By means of the oxidation of {beta}-pinene by ozone in an aerosol chamber, the kinetic isotope effect of this reaction was determined. In southern Germany, air samples for the {delta}({sup 13}C) analysis were collected using a zeppelin. This enables a height-resolved measurement of {delta}({sup 13}C) values. Based on these measurements, the average photochemical age for methanol, toluene and p-xylene at different heights was calculated.

  14. Prediction of radiation ratio and sound transmission of complex extruded panel using wavenumber domain Unite element and boundary element methods

    International Nuclear Information System (INIS)

    Kim, H; Ryue, J; Thompson, D J; Müller, A D

    2016-01-01

    Recently, complex shaped aluminium panels have been adopted in many structures to make them lighter and stronger. The vibro-acoustic behaviour of these complex panels has been of interest for many years but conventional finite element and boundary element methods are not efficient to predict their performance at higher frequencies. Where the cross-sectional properties of the panels are constant in one direction, wavenumber domain numerical analysis can be applied and this becomes more suitable for panels with complex cross-sectional geometries. In this paper, a coupled wavenumber domain finite element and boundary element method is applied to predict the sound radiation from and sound transmission through a double-layered aluminium extruded panel, having a typical shape used in railway carriages. The predicted results are compared with measured ones carried out on a finite length panel and good agreement is found. (paper)

  15. pH-induced photocurrent switching based on a highly stable drop-casting film of imidazole moiety-containing dinuclear Ru(II) Complex

    International Nuclear Information System (INIS)

    Xue, Long-Xin; Duan, Zhi-Ming; Jia, Jia; Wang, Ke-Zhi; Haga, Masa-aki

    2014-01-01

    Graphical abstract: > Solvent-casting Ru(II) complex modified electrode. > Positive shifting of half-wave potentials of Ru(III)/Ru(II) by pH decreases. > Greatly enhanced cathodic photocurrents by pH decreases. - Highlights: • Solvent-casting Ru(II) complex modified electrode. • Positive shifting of half-wave potentials of Ru(III)/Ru(II) by pH decreases. • Greatly enhanced cathodic photocurrents by pH decreases. - Abstract: A new dinuclear Ru(II) complex of [(H 2 L 1 )Ru(H 2 L 2 )Ru(H 2 L 1 )](ClO 4 ) 4 {H 2 L 1 = 2,6-bis(2-benzimidazolyl)pyridine; H 2 L 2 = 2,6-bis(4-([2,2′:6′,2″-terpyridin]-4′-yl)phenyl)-1,5- dihydrobenzo[1,2-d:4,5-d’]diimidazole} is synthesized and characterized. The Ru(II) complex modified indium-tin oxide electrode prepared using a drop-casting method, exhibited a couple of stable surface-confined Ru(III)/Ru(II)-based redox waves centered at +0.65 V vs saturated calomel electrode that were almost unchanged after 50 consecutive cyclic voltammetry scanning. The modified electrode showed pH-dependent redox behaviors with the formal potential being decreased by 430 mV due to the occurrance of the proton-coupled redox reactions. The cathodic photocurrent generation of the modified electrode was also found to be highly pH-dependent, switching from an “off” state at pH ∼11.0 to an “on” state at pH = 2.20 with an enhancement factor of 18. The modified electrode was shown to have promising applications as photoelectrochemical pH sensing and switching devices

  16. Hippocampal and neocortical metabolite ratio in patients with complex partial seizure: short TE and long TE techniques using single voxel proton MR spectroscopy

    International Nuclear Information System (INIS)

    Chung, Jin Il; Kim, Dong Ik; Lee, Byung In; Lee, Seung Ik; Yoon, Pyeong Ho

    2000-01-01

    To compare hippocampal and neocortical metabolite ratios using single-voxel proton MR spectroscopy with different echo times in patients with complex partial seizure. Using a GE Signa 1.5T scanner with STEAM and PRESS sequences, automated single voxel proton MRS was used to determine metabolite ratio differences in the hippocampus and neocortex of nine complex partial seizure patients (mesial temporal sclerosis (n=3D5), status epilepticus (n=3D1), tumor (n=3D1), cortical dysplasia (n=3D1), occipital lobe epilepsy (n=3D1)). A total of 20 examinations were performed in the region of the hippocampus (n=3D17), temporal neocortex (n=3D1), and parieto-occipital gray matter (n=3D1). Voxel size range was 5.2-17.4 cm 3 . The calculated creatine (Cr) peak was employed as an internal reference and the relative ratio of N-acetylaspartate (NAA) and choline (Cho) was calculated for both short and long echo times using an automated PROBE/SV (GE Medical Systems) package. Each NAA/Cho ratio obtained using both PRESS and STEAM techniques was compared by means of statistical analysis (paired Student t-test). Using PRESS (long TE, 272 ms), NAA/Cho ratios were successfully calculated in 16 of 20 examinations; in four this was not possible due to noise levels of the Cr and Cho peaks. Using STEAM (short TE, 30 ms) NAA/Cho ratios were successfully calculated in 19 of 20 examinations; in one, the Cho peak could not be measured. Using PRESS and STEAM, mean and standard deviations for the NAA/Cho ratio were 1.22±0.50 and 1.16±0.36, respectively. There were no statistically significant differences in this ratio between the short and long TE method (p less than 0.01). In complex partial seizure patients, no significant metabolite differences were found between short and long echo times of single voxel proton MR spectroscopy. The metabolite ratio at different echo times can be reliably obtained using this simplified and automated PROBE/SV quantitation method. (author)

  17. Hippocampal and neocortical metabolite ratio in patients with complex partial seizure: short TE and long TE techniques using single voxel proton MR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Jin Il; Kim, Dong Ik; Lee, Byung In; Lee, Seung Ik; Yoon, Pyeong Ho [Medical College, Yonsei University, Seoul (Korea, Republic of)

    2000-08-01

    To compare hippocampal and neocortical metabolite ratios using single-voxel proton MR spectroscopy with different echo times in patients with complex partial seizure. Using a GE Signa 1.5T scanner with STEAM and PRESS sequences, automated single voxel proton MRS was used to determine metabolite ratio differences in the hippocampus and neocortex of nine complex partial seizure patients (mesial temporal sclerosis (n=3D5), status epilepticus (n=3D1), tumor (n=3D1), cortical dysplasia (n=3D1), occipital lobe epilepsy (n=3D1)). A total of 20 examinations were performed in the region of the hippocampus (n=3D17), temporal neocortex (n=3D1), and parieto-occipital gray matter (n=3D1). Voxel size range was 5.2-17.4 cm{sup 3}. The calculated creatine (Cr) peak was employed as an internal reference and the relative ratio of N-acetylaspartate (NAA) and choline (Cho) was calculated for both short and long echo times using an automated PROBE/SV (GE Medical Systems) package. Each NAA/Cho ratio obtained using both PRESS and STEAM techniques was compared by means of statistical analysis (paired Student t-test). Using PRESS (long TE, 272 ms), NAA/Cho ratios were successfully calculated in 16 of 20 examinations; in four this was not possible due to noise levels of the Cr and Cho peaks. Using STEAM (short TE, 30 ms) NAA/Cho ratios were successfully calculated in 19 of 20 examinations; in one, the Cho peak could not be measured. Using PRESS and STEAM, mean and standard deviations for the NAA/Cho ratio were 1.22{+-}0.50 and 1.16{+-}0.36, respectively. There were no statistically significant differences in this ratio between the short and long TE method (p less than 0.01). In complex partial seizure patients, no significant metabolite differences were found between short and long echo times of single voxel proton MR spectroscopy. The metabolite ratio at different echo times can be reliably obtained using this simplified and automated PROBE/SV quantitation method. (author)

  18. Study and validity of 13C stable carbon isotopic ratio analysis by mass spectrometry and 2H site-specific natural isotopic fractionation by nuclear magnetic resonance isotopic measurements to characterize and control the authenticity of honey

    International Nuclear Information System (INIS)

    Cotte, J.F.; Casabianca, H.; Lheritier, J.; Perrucchietti, C.; Sanglar, C.; Waton, H.; Grenier-Loustalot, M.F.

    2007-01-01

    Honey samples were analyzed by stable carbon isotopic ratio analysis by mass spectrometry (SCIRA-MS) and site-specific natural isotopic fractionation measured by nuclear magnetic resonance (SNIF-NMR) to first determine their potentials for characterizing the substance and then to combat adulteration. Honey samples from several geographic and botanical origins were analyzed. The δ 13 C parameter was not significant for characterizing an origin, while the (D/H) I ratio could be used to differentiate certain single-flower varieties. Application of the official control method of adding a C 4 syrup (AOAC official method 998.12) to our authentic samples revealed anomalies resulting from SCIRA indices that were more negative than -1 per mille (permil). A filtration step was added to the experimental procedure and provided results that were compliant with Natural origin of our honey samples. In addition, spiking with a C 4 syrup could be detected starting at 9-10%. The use of SNIF-NMR is limited by the detection of a syrup spike starting only at 20%, which is far from satisfying

  19. Authenticity of rice (Oryza sativa L.) geographical origin based on analysis of C, N, O and S stable isotope ratios: a preliminary case report in Korea, China and Philippine.

    Science.gov (United States)

    Chung, Ill-Min; Kim, Jae-Kwang; Prabakaran, Mayakrishnan; Yang, Jin-Hee; Kim, Seung-Hyun

    2016-05-01

    Although rice (Oryza sativa L.) is the third largest food crop, relatively fewer studies have been reported on rice geographical origin based on light element isotope ratios in comparison with other foods such as wine, beef, juice, oil and milk. Therefore this study tries to discriminate the geographical origin of the same rice cultivars grown in different Asian countries using the analysis of C, N, O and S stable isotope ratios and chemometrics. The δ(15) NAIR , δ(18) OVSMOW and δ(34) SVCDT values of brown rice were more markedly influenced by geographical origin than was the δ(13) CVPDB value. In particular, the combination of δ(18) OVSMOW and δ(34) SVCDT more efficiently discriminated rice geographical origin than did the remaining combinations. Principal component analysis (PCA) revealed a clear discrimination between different rice geographical origins but not between rice genotypes. In particular, the first components of PCA discriminated rice cultivated in the Philippines from rice cultivated in China and Korea. The present findings suggest that analysis of the light element isotope composition combined with chemometrics can be potentially applicable to discriminate rice geographical origin and also may provide a valuable insight into the control of improper or fraudulent labeling regarding the geographical origin of rice worldwide. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  20. Synthesis and X-ray Crystal Structure of a Stable cis-1,2-bis(diphenylphosphinoethene Monodentate Thiolate Platinum Complex and TGA Studies of its Precursors

    Directory of Open Access Journals (Sweden)

    Vaz Rodrigo H.

    2002-01-01

    Full Text Available The stable Pt(II complex [Pt(SPh2(dppen (4, (dppen, Ph2PCH=CHPPh2 was obtained from [PtCl(SPh2(SnPh3cod] (1 (cod = 1,5-cyclooctadiene by reductive elimination reaction of SnClPh3 and substitution of the cod ligand by the diphosphine, albeit in low yields. Yields of 80% were obtained when [Pt(SPh2cod] (3 was used as the starting material instead. The viability of these reactions was suggested by a TG study, performed on the starting materials. Complex 4 was characterized by multinuclear NMR (195Pt, 31P, ¹H and 13C and IR spectroscopies and elemental analysis. The molecular structure, solved by an X-ray diffraction study, exhibted a slightly distorted square-planar geometry and short C=C and Pt-P bond distances which were interpreted in terms of a p interaction between the double bond and the metal-ligand bond, as observed for other diphosphine compounds described previously.

  1. Interaction between Nbp35 and Cfd1 proteins of cytosolic Fe-S cluster assembly reveals a stable complex formation in Entamoeba histolytica.

    Directory of Open Access Journals (Sweden)

    Shadab Anwar

    Full Text Available Iron-Sulfur (Fe-S proteins are involved in many biological functions such as electron transport, photosynthesis, regulation of gene expression and enzymatic activities. Biosynthesis and transfer of Fe-S clusters depend on Fe-S clusters assembly processes such as ISC, SUF, NIF, and CIA systems. Unlike other eukaryotes which possess ISC and CIA systems, amitochondriate Entamoeba histolytica has retained NIF & CIA systems for Fe-S cluster assembly in the cytosol. In the present study, we have elucidated interaction between two proteins of E. histolytica CIA system, Cytosolic Fe-S cluster deficient 1 (Cfd1 protein and Nucleotide binding protein 35 (Nbp35. In-silico analysis showed that structural regions ranging from amino acid residues (P33-K35, G131-V135 and I147-E151 of Nbp35 and (G5-V6, M34-D39 and G46-A52 of Cfd1 are involved in the formation of protein-protein complex. Furthermore, Molecular dynamic (MD simulations study suggested that hydrophobic forces surpass over hydrophilic forces between Nbp35 and Cfd1 and Van-der-Waal interaction plays crucial role in the formation of stable complex. Both proteins were separately cloned, expressed as recombinant fusion proteins in E. coli and purified to homogeneity by affinity column chromatography. Physical interaction between Nbp35 and Cfd1 proteins was confirmed in vitro by co-purification of recombinant Nbp35 with thrombin digested Cfd1 and in vivo by pull down assay and immunoprecipitation. The insilico, in vitro as well as in vivo results prove a stable interaction between these two proteins, supporting the possibility of its involvement in Fe-S cluster transfer to target apo-proteins through CIA machinery in E. histolytica. Our study indicates that initial synthesis of a Fe-S precursor in mitochondria is not necessary for the formation of Cfd1-Nbp35 complex. Thus, Cfd1 and Nbp35 with the help of cytosolic NifS and NifU proteins can participate in the maturation of non-mitosomal Fe-S proteins

  2. Stable isotopes

    International Nuclear Information System (INIS)

    Evans, D.K.

    1986-01-01

    Seventy-five percent of the world's stable isotope supply comes from one producer, Oak Ridge Nuclear Laboratory (ORNL) in the US. Canadian concern is that foreign needs will be met only after domestic needs, thus creating a shortage of stable isotopes in Canada. This article describes the present situation in Canada (availability and cost) of stable isotopes, the isotope enrichment techniques, and related research programs at Chalk River Nuclear Laboratories (CRNL)

  3. Complex-based OCT angiography algorithm recovers microvascular information better than amplitude- or phase-based algorithms in phase-stable systems.

    Science.gov (United States)

    Xu, Jingjiang; Song, Shaozhen; Li, Yuandong; Wang, Ruikang K

    2017-12-19

    Optical coherence tomography angiography (OCTA) is increasingly becoming a popular inspection tool for biomedical imaging applications. By exploring the amplitude, phase and complex information available in OCT signals, numerous algorithms have been proposed that contrast functional vessel networks within microcirculatory tissue beds. However, it is not clear which algorithm delivers optimal imaging performance. Here, we investigate systematically how amplitude and phase information have an impact on the OCTA imaging performance, to establish the relationship of amplitude and phase stability with OCT signal-to-noise ratio (SNR), time interval and particle dynamics. With either repeated A-scan or repeated B-scan imaging protocols, the amplitude noise increases with the increase of OCT SNR; however, the phase noise does the opposite, i.e. it increases with the decrease of OCT SNR. Coupled with experimental measurements, we utilize a simple Monte Carlo (MC) model to simulate the performance of amplitude-, phase- and complex-based algorithms for OCTA imaging, the results of which suggest that complex-based algorithms deliver the best performance when the phase noise is  algorithm delivers better performance than either the amplitude- or phase-based algorithms for both the repeated A-scan and the B-scan imaging protocols, which agrees well with the conclusion drawn from the MC simulations.

  4. A likelihood ratio-based method to predict exact pedigrees for complex families from next-generation sequencing data.

    Science.gov (United States)

    Heinrich, Verena; Kamphans, Tom; Mundlos, Stefan; Robinson, Peter N; Krawitz, Peter M

    2017-01-01

    Next generation sequencing technology considerably changed the way we screen for pathogenic mutations in rare Mendelian disorders. However, the identification of the disease-causing mutation amongst thousands of variants of partly unknown relevance is still challenging and efficient techniques that reduce the genomic search space play a decisive role. Often segregation- or linkage analysis are used to prioritize candidates, however, these approaches require correct information about the degree of relationship among the sequenced samples. For quality assurance an automated control of pedigree structures and sample assignment is therefore highly desirable in order to detect label mix-ups that might otherwise corrupt downstream analysis. We developed an algorithm based on likelihood ratios that discriminates between different classes of relationship for an arbitrary number of genotyped samples. By identifying the most likely class we are able to reconstruct entire pedigrees iteratively, even for highly consanguineous families. We tested our approach on exome data of different sequencing studies and achieved high precision for all pedigree predictions. By analyzing the precision for varying degrees of relatedness or inbreeding we could show that a prediction is robust down to magnitudes of a few hundred loci. A java standalone application that computes the relationships between multiple samples as well as a Rscript that visualizes the pedigree information is available for download as well as a web service at www.gene-talk.de CONTACT: heinrich@molgen.mpg.deSupplementary information: Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press.

  5. The sources and evolution of mineralising fluids in iron oxide-copper-gold systems, Norrbotten, Sweden: Constraints from Br/Cl ratios and stable Cl isotopes of fluid inclusion leachates

    Science.gov (United States)

    Gleeson, S. A.; Smith, M. P.

    2009-10-01

    We have analysed the halogen concentrations and chlorine stable isotope composition of fluid inclusion leachates from three spatially associated Fe-oxide ± Cu ± Au mineralising systems in Norrbotten, Sweden. Fluid inclusions in late-stage veins in Fe-oxide-apatite deposits contain saline brines and have a wide range of Br/Cl molar ratios, from 0.2 to 1.1 × 10 -3 and δ 37Cl values from -3.1‰ to -1.0‰. Leachates from saline fluid inclusions from the Greenstone and Porphyry hosted Cu-Au prospects have Br/Cl ratios that range from 0.2 to 0.5 × 10 -3 and δ 37Cl values from -5.6‰ to -1.3‰. Finally, the Cu-Au deposits hosted by the Nautanen Deformation Zone (NDZ) have Br/Cl molar ratios from 0.4 to 1.1 × 10 -3 and δ 37Cl values that range from -2.4‰ to +0.5‰, although the bulk of the data fall within 0‰ ± 0.5‰. The Br/Cl ratios of leachates are consistent with the derivation of salinity from magmatic sources or from the dissolution of halite. Most of the isotopic data from the Fe-oxide-apatite and Greenstone deposits are consistent with a mantle derived source of the chlorine, with the exception of the four samples with the most negative values. The origin of the low δ 37Cl values in these samples is unknown but we suggest that there may have been some modification of the Cl-isotope signature due to fractionation between the mineralising fluids and Cl-rich silicate assemblages found in the alteration haloes around the deposits. If such a process has occurred then a modified crustal source of the chlorine for all the samples cannot be ruled out although the amount of fractionation necessary to generate the low δ 37Cl values would be significantly larger. The source of Cl in the NDZ deposits has a crustal signature, which suggests the Cl in this system may be derived from (meta-) evaporites or from input from crustal melts such as granitic pegmatites of the Lina Suite.

  6. The physical properties of giant molecular cloud complexes in the outer Galaxy - Implications for the ratio of H2 column density to (C-12)O intensity

    Science.gov (United States)

    Sodroski, T. J.

    1991-01-01

    The physical properties of 35 giant molecular cloud complexes in the outer Galaxy were derived from the Goddard-Columbia surveys of the Galactic plane region (Dame et al., 1987). The spatial and radial velocity boundaries for the individual cloud complexes were estimated by analyzing the spatial and velocity structure of emission features in the (C-12)O surveys, and the distance to each cmplex was determined kinematically on the assumption of a flat rotation curve. The ratio of the H2 column density to the (C-12)O intensity for the outer Galaxy complexes was found to be about 6.0 x 10 to the 20th molecules/sq cm K per km/sec, which is by a factor of 2-3 greater than the value derived by other auhtors for the inner Galaxy complexes. This increase in the H2 column density/(C-12)O intensity with the distance from with the Galactic center is consistent with predictions of the optically thick cloudlet model of giant molecular cloud complexes.

  7. RNA-Based Stable Isotope Probing Suggests Allobaculum spp. as Particularly Active Glucose Assimilators in a Complex Murine Microbiota Cultured In Vitro

    Directory of Open Access Journals (Sweden)

    Elena Herrmann

    2017-01-01

    Full Text Available RNA-based stable isotope probing (RNA-SIP and metabolic profiling were used to detect actively glucose-consuming bacteria in a complex microbial community obtained from a murine model system. A faeces-derived microbiota was incubated under anaerobic conditions for 0, 2, and 4 h with 40 mM [U13C]glucose. Isopycnic density gradient ultracentrifugation and fractionation of isolated RNA into labeled and unlabeled fractions followed by 16S rRNA sequencing showed a quick adaptation of the bacterial community in response to the added sugar, which was dominated by unclassified Lachnospiraceae species. Inspection of distinct fractions of isotope-labeled RNA revealed Allobaculum spp. as particularly active glucose utilizers in the system, as the corresponding RNA showed significantly higher proportions among the labeled RNA. With time, the labeled sugar was used by a wider spectrum of faecal bacteria. Metabolic profiling indicated rapid fermentation of [U13C]glucose, with lactate, acetate, and propionate being the principal 13C-labeled fermentation products, and suggested that “cross-feeding” occurred in the system. RNA-SIP combined with metabolic profiling of 13C-labeled products allowed insights into the microbial assimilation of a general model substrate, demonstrating the appropriateness of this technology to study assimilation processes of nutritionally more relevant substrates, for example, prebiotic carbohydrates, in the gut microbiota of mice as a model system.

  8. An Atypical Human Induced Pluripotent Stem Cell Line With a Complex, Stable, and Balanced Genomic Rearrangement Including a Large De Novo 1q Uniparental Disomy

    Science.gov (United States)

    Steichen, Clara; Maluenda, Jérôme; Tosca, Lucie; Luce, Eléanor; Pineau, Dominique; Dianat, Noushin; Hannoun, Zara; Tachdjian, Gérard; Melki, Judith

    2015-01-01

    Human induced pluripotent stem cells (hiPSCs) hold great promise for cell therapy through their use as vital tools for regenerative and personalized medicine. However, the genomic integrity of hiPSCs still raises some concern and is one of the barriers limiting their use in clinical applications. Numerous articles have reported the occurrence of aneuploidies, copy number variations, or single point mutations in hiPSCs, and nonintegrative reprogramming strategies have been developed to minimize the impact of the reprogramming process on the hiPSC genome. Here, we report the characterization of an hiPSC line generated by daily transfections of modified messenger RNAs, displaying several genomic abnormalities. Karyotype analysis showed a complex genomic rearrangement, which remained stable during long-term culture. Fluorescent in situ hybridization analyses were performed on the hiPSC line showing that this karyotype is balanced. Interestingly, single-nucleotide polymorphism analysis revealed the presence of a large 1q region of uniparental disomy (UPD), demonstrating for the first time that UPD can occur in a noncompensatory context during nonintegrative reprogramming of normal fibroblasts. PMID:25650439

  9. Hsp90α forms a stable complex at the cilium neck for the interaction of signalling molecules in IGF-1 receptor signalling.

    Science.gov (United States)

    Wang, Hongzhong; Zou, Xinle; Wei, Zhuang; Wu, Yuan; Li, Rongxia; Zeng, Rong; Chen, Zhengjun; Liao, Kan

    2015-01-01

    The primary cilium is composed of an axoneme that protrudes from the cell surface, a basal body beneath the membrane and a transition neck in between. It is a sensory organelle on the plasma membrane, involved in mediating extracellular signals. In the transition neck region of the cilium, the microtubules change from triplet to doublet microtubules. This region also contains the transition fibres that crosslink the axoneme with the membrane and the necklace proteins that regulate molecules being transported into and out of the cilium. In this protein-enriched, complex area it is important to maintain the correct assembly of all of these proteins. Here, through immunofluorescent staining and protein isolation, we identify the molecular chaperone Hsp90α clustered at the periciliary base. At the transition neck region, phosphorylated Hsp90α forms a stable ring around the axoneme. Heat shock treatment causes Hsp90α to dissipate and induces resorption of cilia. We further identify that Hsp90α at the transition neck region represents a signalling platform on which IRS-1 interacts with intracellular downstream signalling molecules involved in IGF-1 receptor signalling. © 2015. Published by The Company of Biologists Ltd.

  10. Adding complex terrain and stable atmospheric condition capability to the OpenFOAM-based flow solver of the simulator for on/offshore wind farm applications (SOWFA

    Directory of Open Access Journals (Sweden)

    Churchfield Matthew J.

    2014-01-01

    Full Text Available The National Renewable Energy Laboratory's Simulator for On/Offshore Wind Farm Applications contains an OpenFOAM-based flow solver for performing large-eddy simulation of flow through wind plants. The solver computes the atmospheric boundary layer flow and models turbines with actuator lines. Until recently, the solver was limited to flows over flat terrain and could only use the standard Smagorinsky subgrid-scale model. In this work, we present our improvements to the flow solver that enable us to 1 use any OpenFOAM-standard subgrid-scale model and 2 simulate flow over complex terrain. We used the flow solver to compute a stably stratified atmospheric boundary layer using both the standard and the Lagrangian-averaged scale-independent dynamic Smagorinsky models. Surprisingly, the results using the standard Smagorinsky model compare well to other researchers' results of the same case, although it is often said that the standard Smagorinsky model is too dissipative for accurate stable stratification calculations. The scale-independent dynamic subgrid-scale model produced poor results, probably due to the spikes in model constant with values as high as 4.6. We applied a simple bounding of the model constant to remove these spikes, which caused the model to produce results much more in line with other researchers' results. We also computed flow over a simple hilly terrain and performed some basic qualitative analysis to verify the proper operation of the terrain-local surface stress model we employed.

  11. Stable carbon and hydrogen isotope analysis of methyl tert-butyl ether and tert-amyl methyl ether by purge and trap-gas chromatography-isotope ratio mass spectrometry: method evaluation and application.

    Science.gov (United States)

    Kujawinski, Dorothea M; Stephan, Manuel; Jochmann, Maik A; Krajenke, Karen; Haas, Joe; Schmidt, Torsten C

    2010-01-01

    In order to monitor the behaviour of contaminants in the aqueous environment effective enrichment techniques often have to be employed due to their low concentrations. In this work a robust and sensitive purge and trap-gas chromatography-isotope ratio mass spectrometry method for carbon and hydrogen isotope analysis of fuel oxygenates in water is presented. The method evaluation included the determination of method detection limits, accuracy and reproducibility of deltaD and delta(13)C values. Lowest concentrations at which reliable delta(13)C values could be determined were 5 microg L(-1) and 28 microg L(-1) for TAME and MTBE, respectively. Stable deltaD values for MTBE and TAME could be achieved for concentrations as low as 25 and 50 microg L(-1). Good long-term reproducibility of delta(13)C and deltaD values was obtained for all target compounds. But deltaD values varying more than 5 per thousand were observed using different thermal conversion tubes. Thus, a correction of deltaD values in the analysis of groundwater samples was necessary to guarantee comparability of the results. The applicability of this method was shown by the analysis of groundwater samples from a gasoline contaminated site. By two dimensional isotope analysis two locations within this site were identified at which anaerobic and aerobic degradation of methyl tert-butyl ether occurred.

  12. Forensic analysis of explosives using isotope ratio mass spectrometry (IRMS)--part 2: forensic inter-laboratory trial: bulk carbon and nitrogen stable isotopes in a range of chemical compounds (Australia and New Zealand).

    Science.gov (United States)

    Benson, Sarah J; Lennard, Christopher J; Maynard, Philip; Hill, David M; Andrew, Anita S; Neal, Ken; Stuart-Williams, Hilary; Hope, Janet; Walker, G Stewart; Roux, Claude

    2010-01-01

    Comparability of data over time and between laboratories is a key issue for consideration in the development of global databases, and more broadly for quality assurance in general. One mechanism that can be utilized for evaluating traceability is an inter-laboratory trial. This paper addresses an inter-laboratory trial conducted across a number of Australian and New Zealand isotope ratio mass spectrometry (IRMS) laboratories. The main objective of this trial was to determine whether IRMS laboratories in these countries would record comparable values for the distributed samples. Four carbon containing and four nitrogen containing compounds were distributed to seven laboratories in Australia and one in New Zealand. The laboratories were requested to analyze the samples using their standard procedures. The data from each laboratory was evaluated collectively using International Standard ISO 13528 (Statistical methods for use in proficiency testing by inter-laboratory comparisons). "Warning signals" were raised against one participant in this trial. "Action signals" requiring corrective action were raised against four participants. These participants reviewed the data and possible sources for the discrepancies. This inter-laboratory trial was successful in providing an initial snapshot of the potential for traceability between the participating laboratories. The statistical methods described in this article could be used as a model for others needing to evaluate stable isotope results derived from multiple laboratories, e.g., inter-laboratory trials/proficiency testing. Ongoing trials will be conducted to improve traceability across the Australian and New Zealand IRMS community.

  13. Complementing approaches to demonstrate chlorinated solvent biodegradation in a complex pollution plume: Mass balance, PCR and compound-specific stable isotope analysis

    Science.gov (United States)

    Courbet, Christelle; Rivière, Agnès; Jeannottat, Simon; Rinaldi, Sandro; Hunkeler, Daniel; Bendjoudi, Hocine; de Marsily, Ghislain

    2011-11-01

    This work describes the use of different complementing methods (mass balance, polymerase chain reaction assays and compound-specific stable isotope analysis) to demonstrate the existence and effectiveness of biodegradation of chlorinated solvents in an alluvial aquifer. The solvent-contaminated site is an old chemical factory located in an alluvial plain in France. As most of the chlorinated contaminants currently found in the groundwater at this site were produced by local industries at various times in the past, it is not enough to analyze chlorinated solvent concentrations along a flow path to convincingly demonstrate biodegradation. Moreover, only a few data were initially available to characterize the geochemical conditions at this site, which were apparently complex at the source zone due to (i) the presence of a steady oxygen supply to the groundwater by irrigation canal losses and river infiltration and (ii) an alkaline pH higher than 10 due to former underground lime disposal. A demonstration of the existence of biodegradation processes was however required by the regulatory authority within a timeframe that did not allow a full geochemical characterization of such a complex site. Thus a combination of different fast methods was used to obtain a proof of the biodegradation occurrence. First, a mass balance analysis was performed which revealed the existence of a strong natural attenuation process (biodegradation, volatilization or dilution), despite the huge uncertainty on these calculations. Second, a good agreement was found between carbon isotopic measurements and PCR assays (based on 16S RNA gene sequences and functional genes), which clearly indicated reductive dechlorination of different hydrocarbons (Tetrachloroethene—PCE-, Trichloroethene—TCE-, 1,2- cisDichloroethene— cis-1,2-DCE-, 1,2- transDichloroethene— trans-1,2-DCE-, 1,1-Dichloroethene—1,1-DCE-, and Vinyl Chloride—VC) to ethene. According to these carbon isotope measurements

  14. Unpredictably Stable

    DEFF Research Database (Denmark)

    Failla, Virgilio; Melillo, Francesca; Reichstein, Toke

    2014-01-01

    Is entrepreneurship a more stable career choice for high employment turnover individuals? We find that a transition to entrepreneurship induces a shift towards stayer behavior and identify job matching, job satisfaction and lock-in effects as main drivers. These findings have major implications...

  15. Vehicle emissions of greenhouse gases and related tracers from a tunnel study: : CO: CO2, N2O: CO2, CH4: CO2, O2: CO2 ratios, and the stable isotopes 13C and 18O in CO2 and CO

    NARCIS (Netherlands)

    Popa, Maria Elena; Vollmer, M. K.; Jordan, A.; Brand, W. A.; Pathirana, S. L.; Rothe, M.; Röckmann, T.

    2014-01-01

    Measurements of CO2, CO, N2O and CH4 mole fractions, O2/N2 ratios and the stable isotopes 13C and 18O in CO2 and CO have been performed in air samples from the Islisberg highway tunnel (Switzerland). The molar CO : CO2 ratios, with an average of (4.15 ± 0.34) ppb:ppm, are lower than reported in

  16. Stable particles

    International Nuclear Information System (INIS)

    Samios, N.P.

    1993-01-01

    I have been asked to review the subject of stable particles, essentially the particles that eventually comprised the meson and baryon octets. with a few more additions -- with an emphasis on the contributions made by experiments utilizing the bubble chamber technique. In this activity, much work had been done by the photographic emulsion technique and cloud chambers-exposed to cosmic rays as well as accelerator based beams. In fact, many if not most of the stable particles were found by these latter two techniques, however, the forte of the bubble chamber (coupled with the newer and more powerful accelerators) was to verify, and reinforce with large statistics, the existence of these states, to find some of the more difficult ones, mainly neutrals and further to elucidate their properties, i.e., spin, parity, lifetimes, decay parameters, etc

  17. Covalent co-immobilization of heparin/laminin complex that with different concentration ratio on titanium surface for selectively direction of platelets and vascular cells behavior

    International Nuclear Information System (INIS)

    Wang, Jian; Chen, Yuan; Liu, Tao; Wang, Xue; Liu, Yang; Wang, Yuan; Chen, Junying; Huang, Nan

    2014-01-01

    Highlights: • Extracellular matrix inspired surface modification with fibronectin, heparin and VEGF to construct a favorable microenvironment for selectively anticoagulant and promote endothelialization. • Take the advantage of specific intermolecular interaction, the bioactivity of above biomolecules was more efficiently maintained in compared with the common used covalent immobilization method. • Poly-l-lysine was used as a novel interlayer for surface amination, and in comparison, PLL coating was more feasible and the degradation product had no harm to human body. - Abstract: Surface biofunctional modification of coronary artery stent to improve the hemocompatibility and selectively accelerate endothelium regeneration but prevent restenosis have been become a new hotspot. For this, a novel method was developed in this work by co-immobilization of Ln and heparin complex on poly-L-lysine modified Ti surface. Take the advantage of the specific interaction between Ln and heparin, Ln and heparin complexes with different concentration ratios were set up for creating different exposure density of these two types of biomolecules. According to biocompatibility evaluation results, the Hep/Ln complexes modified surface displayed less platelet adhesion and activation. Especially, on L(150)H and L(200)H surface, the AT III binding quantity, APTT value and anti-coagulation property of modified surface were significantly promoted. Furthermore, the adherent density and proliferation activity of ECs and EPCs were positively correlated with Ln concentration. Notably, the proliferation of both ECs and EPCs on L(100)H, L(150)H and L(200)H surface were greatly promoted. Another hand, the proliferation activity of SMCs was significantly inhibited on Hep/Ln modified surfaces, which was considered mainly due to the inhibitory effect of heparin to SMCs. According to the existing results, this study demonstrated that in a certain range of heparin and laminin concentration ratio

  18. Synergistic effect of signaling from receptors of soluble platelet agonists and outside-in signaling in formation of a stable fibrinogen-integrin αIIbβ3-actin cytoskeleton complex.

    Science.gov (United States)

    Budnik, Ivan; Shenkman, Boris; Savion, Naphtali

    2015-01-01

    Thrombus formation in the injured vessel wall is a highly complex process involving various blood-born components that go through specific temporal and spatial changes as observed by intravital videomicroscopy. Platelets bind transiently to the developing thrombus and may either become stably incorporated into or disengage from the thrombus. The aim of the present study was to reveal the processes involved in the formation of a stable thrombus. Platelet-rich plasma and washed platelets were studied by the aggregometer. The aggregate stability was challenged by eptifibatide. Platelet Triton-insoluble fraction was prepared and the actin and αIIb content in the cytoskeleton was analyzed by western blot. Maximal actin polymerization is achieved 1min after platelet activation while maximal αIIbβ3-actin cytoskeleton association requires 5 to 10min of activation and fibrinogen-mediated platelet-to-platelet bridging. Thus, actin polymerization is dependent on platelet activation and requires neither αIIbβ3 integrin occupation nor platelet aggregation. Formation of a stable aggregate requires platelet activation for more than 1min, complete increase in actin cytoskeleton fraction and partial association of αIIbβ3 with the actin cytoskeleton. However, direct αIIbβ3 activation is not sufficient for cytoskeleton complex formation. Thus, stable αIIbβ3-fibrinogen interaction, representing stable aggregate, is achieved after more than 1min agonist activation, involving inside-out and outside-in signaling but not after direct integrin activation, involving only outside-in signaling. Formation of a stable fibrinogen-αIIbβ3-actin cytoskeleton complex is the result of the combined effect of platelet stimulation by soluble agonists, activation of αIIbβ3, fibrinogen binding and platelet-to-platelet bridging. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Stable isotope mass spectrometry in petroleum exploration

    International Nuclear Information System (INIS)

    Mathur, Manju

    1997-01-01

    The stable isotope mass spectrometry plays an important role to evaluate the stable isotopic composition of hydrocarbons. The isotopic ratios of certain elements in petroleum samples reflect certain characteristics which are useful for petroleum exploration

  20. Stable isotopes

    International Nuclear Information System (INIS)

    Brazier, J.L.; Guinamant, J.L.

    1995-01-01

    According to the progress which has been realised in the technology of separating and measuring isotopes, the stable isotopes are used as preferable 'labelling elements' for big number of applications. The isotopic composition of natural products shows significant variations as a result of different reasons like the climate, the seasons, or their geographic origins. So, it was proved that the same product has a different isotopic composition of alimentary and agriculture products. It is also important in detecting the pharmacological and medical chemicals. This review article deals with the technology, like chromatography and spectrophotometry, adapted to this aim, and some important applications. 17 refs. 6 figs

  1. Stable Tetraquarks

    Energy Technology Data Exchange (ETDEWEB)

    Quigg, Chris [Fermilab

    2018-04-13

    For very heavy quarks, relations derived from heavy-quark symmetry imply novel narrow doubly heavy tetraquark states containing two heavy quarks and two light antiquarks. We predict that double-beauty states will be stable against strong decays, whereas the double-charm states and mixed beauty+charm states will dissociate into pairs of heavy-light mesons. Observing a new double-beauty state through its weak decays would establish the existence of tetraquarks and illuminate the role of heavy color-antitriplet diquarks as hadron constituents.

  2. Stable beams

    CERN Multimedia

    2015-01-01

    Stable beams: two simple words that carry so much meaning at CERN. When LHC page one switched from "squeeze" to "stable beams" at 10.40 a.m. on Wednesday, 3 June, it triggered scenes of jubilation in control rooms around the CERN sites, as the LHC experiments started to record physics data for the first time in 27 months. This is what CERN is here for, and it’s great to be back in business after such a long period of preparation for the next stage in the LHC adventure.   I’ve said it before, but I’ll say it again. This was a great achievement, and testimony to the hard and dedicated work of so many people in the global CERN community. I could start to list the teams that have contributed, but that would be a mistake. Instead, I’d simply like to say that an achievement as impressive as running the LHC – a machine of superlatives in every respect – takes the combined effort and enthusiasm of everyone ...

  3. The Liquidity Coverage Ratio: the need for further complementary ratios?

    OpenAIRE

    Ojo, Marianne

    2013-01-01

    This paper considers components of the Liquidity Coverage Ratio – as well as certain prevailing gaps which may necessitate the introduction of a complementary liquidity ratio. The definitions and objectives accorded to the Liquidity Coverage Ratio (LCR) and Net Stable Funding Ratio (NSFR) highlight the focus which is accorded to time horizons for funding bank operations. A ratio which would focus on the rate of liquidity transformations and which could also serve as a complementary metric gi...

  4. Complementing approaches to demonstrate chlorinated solvent biodegradation in a complex pollution plume: mass balance, PCR and compound-specific stable isotope analysis.

    OpenAIRE

    Courbet Christelle; Rivière Agnès; Jeannottat Simon; Rinaldi Sandro; Hunkeler Daniel; Bendjoudi Hocine; De Marsily Ghislain

    2011-01-01

    This work describes the use of different complementing methods (mass balance polymerase chain reaction assays and compound specific stable isotope analysis) to demonstrate the existence and effectiveness of biodegradation of chlorinated solvents in an alluvial aquifer. The solvent contaminated site is an old chemical factory located in an alluvial plain in France. As most of the chlorinated contaminants currently found in the groundwater at this site were produced by local industries at vario...

  5. Uses of stable isotopes

    International Nuclear Information System (INIS)

    Axente, Damian

    1998-01-01

    The most important fields of stable isotope use with examples are presented. These are: 1. Isotope dilution analysis: trace analysis, measurements of volumes and masses; 2. Stable isotopes as tracers: transport phenomena, environmental studies, agricultural research, authentication of products and objects, archaeometry, studies of reaction mechanisms, structure and function determination of complex biological entities, studies of metabolism, breath test for diagnostic; 3. Isotope equilibrium effects: measurement of equilibrium effects, investigation of equilibrium conditions, mechanism of drug action, study of natural processes, water cycle, temperature measurements; 4. Stable isotope for advanced nuclear reactors: uranium nitride with 15 N as nuclear fuel, 157 Gd for reactor control. In spite of some difficulties of stable isotope use, particularly related to the analytical techniques, which are slow and expensive, the number of papers reporting on this subject is steadily growing as well as the number of scientific meetings organized by International Isotope Section and IAEA, Gordon Conferences, and regional meeting in Germany, France, etc. Stable isotope application development on large scale is determined by improving their production technologies as well as those of labeled compound and the analytical techniques. (author)

  6. Stable isotope labeling strategy based on coding theory

    Energy Technology Data Exchange (ETDEWEB)

    Kasai, Takuma; Koshiba, Seizo; Yokoyama, Jun; Kigawa, Takanori, E-mail: kigawa@riken.jp [RIKEN Quantitative Biology Center (QBiC), Laboratory for Biomolecular Structure and Dynamics (Japan)

    2015-10-15

    We describe a strategy for stable isotope-aided protein nuclear magnetic resonance (NMR) analysis, called stable isotope encoding. The basic idea of this strategy is that amino-acid selective labeling can be considered as “encoding and decoding” processes, in which the information of amino acid type is encoded by the stable isotope labeling ratio of the corresponding residue and it is decoded by analyzing NMR spectra. According to the idea, the strategy can diminish the required number of labelled samples by increasing information content per sample, enabling discrimination of 19 kinds of non-proline amino acids with only three labeled samples. The idea also enables this strategy to combine with information technologies, such as error detection by check digit, to improve the robustness of analyses with low quality data. Stable isotope encoding will facilitate NMR analyses of proteins under non-ideal conditions, such as those in large complex systems, with low-solubility, and in living cells.

  7. Stable isotope labeling strategy based on coding theory

    International Nuclear Information System (INIS)

    Kasai, Takuma; Koshiba, Seizo; Yokoyama, Jun; Kigawa, Takanori

    2015-01-01

    We describe a strategy for stable isotope-aided protein nuclear magnetic resonance (NMR) analysis, called stable isotope encoding. The basic idea of this strategy is that amino-acid selective labeling can be considered as “encoding and decoding” processes, in which the information of amino acid type is encoded by the stable isotope labeling ratio of the corresponding residue and it is decoded by analyzing NMR spectra. According to the idea, the strategy can diminish the required number of labelled samples by increasing information content per sample, enabling discrimination of 19 kinds of non-proline amino acids with only three labeled samples. The idea also enables this strategy to combine with information technologies, such as error detection by check digit, to improve the robustness of analyses with low quality data. Stable isotope encoding will facilitate NMR analyses of proteins under non-ideal conditions, such as those in large complex systems, with low-solubility, and in living cells

  8. CmRBP50 protein phosphorylation is essential for assembly of a stable phloem-mobile high-affinity ribonucleoprotein complex.

    Science.gov (United States)

    Li, Pingfang; Ham, Byung-Kook; Lucas, William J

    2011-07-01

    RNA-binding proteins (RBPs) form ribonucleoprotein (RNP) complexes that play crucial roles in RNA processing for gene regulation. The angiosperm sieve tube system contains a unique population of transcripts, some of which function as long-distance signaling agents involved in regulating organ development. These phloem-mobile mRNAs are translocated as RNP complexes. One such complex is based on a phloem RBP named Cucurbita maxima RNA-binding protein 50 (CmRBP50), a member of the polypyrimidine track binding protein family. The core of this RNP complex contains six additional phloem proteins. Here, requirements for assembly of this CmRBP50 RNP complex are reported. Phosphorylation sites on CmRBP50 were mapped, and then coimmunoprecipitation and protein overlay studies established that the phosphoserine residues, located at the C terminus of CmRBP50, are critical for RNP complex assembly. In vitro pull-down experiments revealed that three phloem proteins, C. maxima phloem protein 16, C. maxima GTP-binding protein, and C. maxima phosphoinositide-specific phospholipase-like protein, bind directly with CmRBP50. This interaction required CmRBP50 phosphorylation. Gel mobility-shift assays demonstrated that assembly of the CmRBP50-based protein complex results in a system having enhanced binding affinity for phloem-mobile mRNAs carrying polypyrimidine track binding motifs. This property would be essential for effective long-distance translocation of bound mRNA to the target tissues.

  9. Golden Ratio

    Indian Academy of Sciences (India)

    Our attraction to another body increases if the body is symmetricaland in proportion. If a face or a structure is in proportion,we are more likely to notice it and find it beautiful.The universal ratio of beauty is the 'Golden Ratio', found inmany structures. This ratio comes from Fibonacci numbers.In this article, we explore this ...

  10. Golden Ratio

    Indian Academy of Sciences (India)

    Keywords. Fibonacci numbers, golden ratio, Sanskrit prosody, solar panel. Abstract. Our attraction to another body increases if the body is symmetricaland in proportion. If a face or a structure is in proportion,we are more likely to notice it and find it beautiful.The universal ratio of beauty is the 'Golden Ratio', found inmany ...

  11. Golden Ratio

    Indian Academy of Sciences (India)

    Our attraction to another body increases if the body is sym- metrical and in proportion. If a face or a structure is in pro- portion, we are more likely to notice it and find it beautiful. The universal ratio of beauty is the 'Golden Ratio', found in many structures. This ratio comes from Fibonacci numbers. In this article, we explore this ...

  12. New insight from noble gas and stable isotopes of geothermal/hydrothermal fluids at Caviahue-Copahue Volcanic Complex: Boiling steam separation and water-rock interaction at shallow depth

    Science.gov (United States)

    Roulleau, Emilie; Tardani, Daniele; Sano, Yuji; Takahata, Naoto; Vinet, Nicolas; Bravo, Francisco; Muñoz, Carlos; Sanchez, Juan

    2016-12-01

    We measured noble gas and stable isotopes of the geothermal and hydrothermal fluids of the Caviahue-Copahue Volcanic Complex (CCVC), one of the most important geothermal systems in Argentina/Chile, in order to provide new insights into fluid circulation and origin. With the exception of Anfiteatro and Chancho-co geothermal systems, mantle-derived helium dominates in the CCVC fluids, with measured 3He/4He ratios up to 7.86Ra in 2015. Their positive δ15N is an evidence for subducted sediment-derived nitrogen, which is commonly observed in subduction settings. Both He-N2-Ar composition and positive correlation between δD-H2O and δ18O-H2O suggest that the fluids from Anfiteatro and Chancho-co (and partly from Pucon-Mahuida as well, on the southern flank of Copahue volcano) represent a meteoric water composition with a minor magmatic contribution. The Ne, Kr and Xe isotopic compositions are entirely of atmospheric origin, but processes of boiling and steam separation have led to fractionation of their elemental abundances. We modeled the CCVC fluid evolution using Rayleigh distillation curves, considering an initial air saturated geothermal water (ASGW) end-member at 250 and 300 °C, followed by boiling and steam separation at lower temperatures (from 200 °C to 150 °C). Between 2014 and 2015, the CCVC hydrogen and oxygen isotopes shifted from local meteoric water-dominated to andesitic water-dominated signature. This shift is associated with an increase of δ13C values and Stotal, HCl and He contents. These characteristics are consistent with a change in the gas ascent pathway between 2014 and 2015, which in turn induced higher magmatic-hydrothermal contribution in the fluid signature. The composition of the magmatic source of the CCVC fluids is: 3He/4He = 7.7Ra, δ15N = + 6‰, and δ13C = - 6.5‰. Mixing models between air-corrected He and N suggest the involvement of 0.5% to 5% of subducted sediments in the magmatic source. The magmatic sulfur isotopic

  13. Using a combination of radiogenic and stable isotopes coupled with hydrogeochemistry, limnometrics and meteorological data in hydrological research of complex underground mine-pit lake systems: The case of Cueva de la Mora

    Science.gov (United States)

    Sánchez-España, J.; Diez Ercilla, M.; Pérez Cerdán, F.; Yusta, I.

    2012-04-01

    This study presents a combination of radiogenic and stable isotopes (3H, 2H and 18O on pit lake water, and 34S on dissolved sulfate) coupled with bathymetric, meteorological and limnometric investigations, and detailed hydrogeochemical studies to decipher the flooding history and hydrological dynamics of a meromictic and deeply stratified pit lake in SW Spain. The application of these combined techniques has been specially succesful considering the complexity of the studied system, which includes a substantial number of horizontal galleries, shafts and large rooms physically connected to the pit lake. Specific conductance and temperature profiles have depicted a physical structure of the water body which includes four monimolimnetic layers of increasing density with depth. This internal configuration includes m-scale layers separated by sharp transional zones and is rarely observed in natural, fresh water bodies and most other pit lakes. The tritium abundance of the different layers indicate that the deepest water consists in strongly acidified and metal-laden meteoric water infiltrated in the mine system soon after the mine closure in 1971-72. Oxygen and hydrogen isotope ratios of the different layers reflect a sharp stratification with increasing evaporative influence towards the lake surface. The combination of tritium data with the oxygen and hydrogen isotope composition of the different layers suggests a model of pit lake formation with an initial stage of flooding (with entrance of highly metal- and sulfate-loaded mine drainage from the underlying mine galleries) that deeply determined the physical structure and meromictic nature of the lake. After reaching the present water level and morphology, the stagnant, anoxic part of pit lake seems to have remained chemically and isotopically unmodified during its 40 year-old history. Although the pit lake receives significant water input during autumn and winter (which in turn provoke significant volumetric increases

  14. Hydrophobic and electrostatic interactions between cell penetrating peptides and plasmid DNA are important for stable non-covalent complexation and intracellular delivery.

    Science.gov (United States)

    Upadhya, Archana; Sangave, Preeti C

    2016-10-01

    Cell penetrating peptides are useful tools for intracellular delivery of nucleic acids. Delivery of plasmid DNA, a large nucleic acid, poses a challenge for peptide mediated transport. The paper investigates and compares efficacy of five novel peptide designs for complexation of plasmid DNA and subsequent delivery into cells. The peptides were designed to contain reported DNA condensing agents and basic cell penetrating sequences, octa-arginine (R 8 ) and CHK 6 HC coupled to cell penetration accelerating peptides such as Bax inhibitory mutant peptide (KLPVM) and a peptide derived from the Kaposi fibroblast growth factor (kFGF) membrane translocating sequence. A tryptophan rich peptide, an analogue of Pep-3, flanked with CH 3 on either ends was also a part of the study. The peptides were analysed for plasmid DNA complexation, protection of peptide-plasmid DNA complexes against DNase I, serum components and competitive ligands by simple agarose gel electrophoresis techniques. Hemolysis of rat red blood corpuscles (RBCs) in the presence of the peptides was used as a measure of peptide cytotoxicity. Plasmid DNA delivery through the designed peptides was evaluated in two cell lines, human cervical cancer cell line (HeLa) and (NIH/3 T3) mouse embryonic fibroblasts via expression of the secreted alkaline phosphatase (SEAP) reporter gene. The importance of hydrophobic sequences in addition to cationic sequences in peptides for non-covalent plasmid DNA complexation and delivery has been illustrated. An alternative to the employment of fatty acid moieties for enhanced gene transfer has been proposed. Comparison of peptides for plasmid DNA complexation and delivery of peptide-plasmid DNA complexes to cells estimated by expression of a reporter gene, SEAP. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

  15. Stable Isotope (δ13C, δ15N, δ34S) Analysis and Satellite Telemetry Depict the Complexity of Gray Wolf (Canis lupus) Diets in Southwest Alaska

    Science.gov (United States)

    Stanek, A.; Watts, D. E.; Cohn, B. R.; Spencer, P.; Mangipane, B.; Welker, J. M.

    2010-12-01

    Throughout Alaska, gray wolves (Canis lupus) are a top predator of large ungulates. While they primarily rely on ungulates such as moose (Alces alces) and caribou (Rangifer tarandus) as food, they are opportunistic and use alternative resources. The variation and supplemental protein sources in wolf diet has not been studied extensively on live animals currently using the landscape. With large seasonal influxes of Pacific salmon (Oncorhynchus sp.) into Alaska, terrestrial carnivore use of marine species is of particular interest. Using stable isotope (δ13C, δ15N, δ34S) analysis of wolf guard hair and blood, this study aims to determine the proportion of marine derived nutrients (MDN) in the diet of wolf packs within and surrounding Lake Clark National Park and Preserve and Alaska Peninsula and Becharof National Wildlife Refuges in Southwest Alaska. Satellite telemetry from the animals sampled facilitates quantification of landscape use patterns in correspondence with isotopic traits. Wolf pack territories within and surrounding the Lake Clark region appear to vary in spatial extent and in availability of MDN, such as salmon. Initial analysis shows that two packs with smaller home ranges, centrally located around areas with greater salmon availability, have enriched δ15N values compared to packs that have larger home ranges not centralized around salmon spawning waters. This pattern of isotopic enrichment is found in red blood cells, blood serum and hair, representing diets over different time scales. The enrichment in both blood and hair indicates a sustained use of MDN over the previous six to nine months. In the Lake Clark region, simple mixing model estimates suggest that up to 30% of wolf pack diets may be from marine sources. In contrast, packs with larger home ranges and less access to salmon have stable isotope values representative of a terrestrial diet.

  16. Sex ratios

    OpenAIRE

    West, Stuart A; Reece, S E; Sheldon, Ben C

    2002-01-01

    Sex ratio theory attempts to explain variation at all levels (species, population, individual, brood) in the proportion of offspring that are male (the sex ratio). In many cases this work has been extremely successful, providing qualitative and even quantitative explanations of sex ratio variation. However, this is not always the situation, and one of the greatest remaining problems is explaining broad taxonomic patterns. Specifically, why do different organisms show so ...

  17. Direct gas injection method: A simple modification to an elemental analyzer/isotope ratio mass spectrometer for stable isotope analysis of N and C from N2O and CO2 gases in nanomolar concentrations

    Science.gov (United States)

    A simple modification to the Elemental Analyzer coupled to Isotope Ratio Mass-Spectrometer (EA-IRMS) setup is described. This modification allows the users to measure nitrous oxide (N2O) and carbon dioxide (CO2) by injecting the gases directly into an online injector placed befor...

  18. Effects of dietary energy density and digestible protein:energy ratio on de novo lipid synthesis from dietary protein in gilthead sea bream (Sparus aurata) quantified with stable isotopes

    DEFF Research Database (Denmark)

    Ekmann, Kim Schøn; Dalsgaard, Anne Johanne Tang; Holm, Jørgen

    2013-01-01

    to trace the metabolic fate of dietary protein, 1·8% fishmeal was replaced with isotope-labelled whole protein (.98% 13C). The experiment was divided into a growth period lasting 89 d, growing fish from approximately 140 to 350 g, followed by a 3 d period feeding isotope-enriched diets. Isotope ratio MS...

  19. Using nitrogen stable isotope ratios (δ15N) of macroalgae to determine the effectiveness of sewage upgrades: changes in the extent of sewage plumes over four years in Moreton Bay, Australia

    International Nuclear Information System (INIS)

    Costanzo, Simon D.; Udy, James; Longstaff, Ben; Jones, Adrian

    2005-01-01

    Nitrogen loading to aquatic ecosystems from sewage is recognised worldwide as a growing problem. The use of nitrogen stable isotopes as a means of discerning sewage nitrogen in the environment has been used annually by the Ecosystem Health Monitoring Program in Moreton Bay (Australia) since 1997 when the technique was first developed. This ('sewage plume mapping') technique, which measures the δ 15 N isotopic signature of the red macroalga Catenella nipae after incubation in situ, has demonstrated a large reduction in the magnitude and spatial extent of sewage nitrogen within Moreton Bay over the past 5 years. This observed reduction coincides with considerable upgrades to the nitrogen removal efficacy at several sewage treatment plants within the region. This paper describes the observed changes and evaluates whether they can be attributed to the treatment upgrades

  20. Using nitrogen stable isotope ratios ({delta}{sup 15}N) of macroalgae to determine the effectiveness of sewage upgrades: changes in the extent of sewage plumes over four years in Moreton Bay, Australia

    Energy Technology Data Exchange (ETDEWEB)

    Costanzo, Simon D. [National Research Centre for Environmental Toxicology, University of Queensland, 39 Kessels Road, Coopers Plains, QLD 4108 (Australia)]. E-mail: s.costanzo@uq.edu.au; Udy, James [Marine Botany, Centre for Marine Studies, University of Queensland, 4072 (Australia); Longstaff, Ben [Environmental Protection Agency, 80 Meiers Road, Indooroopilly, QLD 4058 (Australia); Jones, Adrian [University of Maryland Center for Environmental Science, P.O. Box 775, Cambridge, MD 21613, USA (United States)

    2005-07-01

    Nitrogen loading to aquatic ecosystems from sewage is recognised worldwide as a growing problem. The use of nitrogen stable isotopes as a means of discerning sewage nitrogen in the environment has been used annually by the Ecosystem Health Monitoring Program in Moreton Bay (Australia) since 1997 when the technique was first developed. This ('sewage plume mapping') technique, which measures the {delta}{sup 15}N isotopic signature of the red macroalga Catenella nipae after incubation in situ, has demonstrated a large reduction in the magnitude and spatial extent of sewage nitrogen within Moreton Bay over the past 5 years. This observed reduction coincides with considerable upgrades to the nitrogen removal efficacy at several sewage treatment plants within the region. This paper describes the observed changes and evaluates whether they can be attributed to the treatment upgrades.

  1. 3,4,3-LI(1,2-HOPO): In Vitro Formation of Highly Stable Lanthanide Complexes Translates into Efficacious In Vivo Europium Decorporation

    Energy Technology Data Exchange (ETDEWEB)

    Sturzbecher-Hoehne, Manuel; Ng Pak Leung, Clara; Daleo, Anthony; Kullgren, Birgitta; Prigent, Anne-Laure; Shuh, David K.; Raymond, Kenneth N.; Abergel, Rebecca J.

    2011-07-13

    The spermine-based hydroxypyridonate octadentate chelator 3,4,3-LI(1,2-HOPO) was investigated for its ability to act as an antennae that sensitizes the emission of Sm{sup III}, Eu{sup III}, and Tb{sup III} in the Visible range (Φ{sub tot} = 0.2 - 7%) and the emission of Pr{sup III}, Nd{sup III}, Sm{sup III}, and Yb{sup III} in the Near Infra-Red range, with decay times varying from 1.78 μs to 805 μs at room temperature. The particular luminescence spectroscopic properties of these lanthanide complexes formed with 3,4,3-LI(1,2-HOPO) were used to characterize their respective solution thermodynamic stabilities as well as those of the corresponding La{sup III}, Gd{sup III}, Dy{sup III}, Ho{sup III}, Er{sup III}, Tm{sup III}, and Lu{sup III} complexes. The remarkably high affinity of 3,4,3-LI(1,2-HOPO) for lanthanide metal ions and the resulting high complex stabilities (pM values ranging from 17.2 for La{sup III} to 23.1 for Yb{sup III}) constitute a necessary but not sufficient criteria to consider this octadentate ligand an optimal candidate for in vivo metal decorporation. The in vivo lanthanide complex stability and decorporation capacity of the ligand were assessed, using the radioactive isotope {sup 152}Eu as a tracer in a rodent model, which provided a direct comparison with the in vitro thermodynamic results and demonstrated the great potential of 3,4,3-LI(1,2-HOPO) as a therapeutic metal chelating agent.

  2. Host-guest chemistry of dendrimer-drug complexes: 7. Formation of stable inclusions between acetylated dendrimers and drugs bearing multiple charges.

    Science.gov (United States)

    Fang, Min; Zhang, Jiahai; Wu, Qinglin; Xu, Tongwen; Cheng, Yiyun

    2012-03-15

    Drug molecules bearing multiple charges usually form precipitates with cationic dendrimers, which presents a challenge during the preparation of dendrimer inclusions for these drugs. In the present study, fully acetylated polyamidoamine (PAMAM) dendrimers were proposed as stable vehicles for drug molecules bearing two negative charges such as Congo red and indocyanine green. NMR techniques including (1)H NMR and (1)H-(1)H NOESY were used to characterize the host-guest chemistry of acetylated dendrimer and these guest molecules. The cationic PAMAM dendrimer was found to form a precipitate with Congo red and indocyanine green, but the acetylated one avoided the formation of cross-linking structures in aqueous solutions. NOESY studies revealed the encapsulation of Congo red and indocyanine green within the interior cavities of PAMAM dendrimers at mild acidic conditions and acetylated dendrimers show much stronger ability to encapsulate the guest molecules than cationic ones. Also, UV-vis-NIR studies suggest that acetylated dendrimers significantly improve the photostability of indocyanine green and prevent the formation of indocyanine green J-aggregates in aqueous solutions. The present study provides a new insight into dendrimer-based host-guest systems, especially for those guest molecules bearing multiple charges. © 2012 American Chemical Society

  3. The NDUFB6 subunit of the mitochondrial respiratory chain complex I is required for electron transfer activity: A proof of principle study on stable and controlled RNA interference in human cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Loublier, Sandrine; Bayot, Aurelien; Rak, Malgorzata; El-Khoury, Riyad; Benit, Paule [Inserm U676, Hopital Robert Debre, F-75019 Paris (France); Universite Paris 7, Faculte de medecine Denis Diderot, IFR02 Paris (France); Rustin, Pierre, E-mail: pierre.rustin@inserm.fr [Inserm U676, Hopital Robert Debre, F-75019 Paris (France); Universite Paris 7, Faculte de medecine Denis Diderot, IFR02 Paris (France)

    2011-10-22

    Highlights: {yields} NDUFB6 is required for activity of mitochondrial complex I in human cell lines. {yields} Lentivirus based RNA interference results in frequent off target insertions. {yields} Flp-In recombinase mediated miRNA insertion allows gene-specific extinction. -- Abstract: Molecular bases of inherited deficiencies of mitochondrial respiratory chain complex I are still unknown in a high proportion of patients. Among 45 subunits making up this large complex, more than half has unknown function(s). Understanding the function of these subunits would contribute to our knowledge on mitochondrial physiology but might also reveal that some of these subunits are not required for the catalytic activity of the complex. A direct consequence of this finding would be the reduction of the number of candidate genes to be sequenced in patients with decreased complex I activity. In this study, we tested two different methods to stably extinct complex I subunits in cultured cells. We first found that lentivirus-mediated shRNA expression frequently resulted in the unpredicted extinction of additional gene(s) beside targeted ones. This can be ascribed to uncontrolled genetic material insertions in the genome of the host cell. This approach thus appeared inappropriate to study unknown functions of a gene. Next, we found it possible to specifically extinct a CI subunit gene by direct insertion of a miR targeting CI subunits in a Flp site (HEK293 Flp-In cells). By using this strategy we unambiguously demonstrated that the NDUFB6 subunit is required for complex I activity, and defined conditions suitable to undertake a systematic and stable extinction of the different supernumerary subunits in human cells.

  4. The NDUFB6 subunit of the mitochondrial respiratory chain complex I is required for electron transfer activity: A proof of principle study on stable and controlled RNA interference in human cell lines

    International Nuclear Information System (INIS)

    Loublier, Sandrine; Bayot, Aurelien; Rak, Malgorzata; El-Khoury, Riyad; Benit, Paule; Rustin, Pierre

    2011-01-01

    Highlights: → NDUFB6 is required for activity of mitochondrial complex I in human cell lines. → Lentivirus based RNA interference results in frequent off target insertions. → Flp-In recombinase mediated miRNA insertion allows gene-specific extinction. -- Abstract: Molecular bases of inherited deficiencies of mitochondrial respiratory chain complex I are still unknown in a high proportion of patients. Among 45 subunits making up this large complex, more than half has unknown function(s). Understanding the function of these subunits would contribute to our knowledge on mitochondrial physiology but might also reveal that some of these subunits are not required for the catalytic activity of the complex. A direct consequence of this finding would be the reduction of the number of candidate genes to be sequenced in patients with decreased complex I activity. In this study, we tested two different methods to stably extinct complex I subunits in cultured cells. We first found that lentivirus-mediated shRNA expression frequently resulted in the unpredicted extinction of additional gene(s) beside targeted ones. This can be ascribed to uncontrolled genetic material insertions in the genome of the host cell. This approach thus appeared inappropriate to study unknown functions of a gene. Next, we found it possible to specifically extinct a CI subunit gene by direct insertion of a miR targeting CI subunits in a Flp site (HEK293 Flp-In cells). By using this strategy we unambiguously demonstrated that the NDUFB6 subunit is required for complex I activity, and defined conditions suitable to undertake a systematic and stable extinction of the different supernumerary subunits in human cells.

  5. A High Molar Extinction Coefficient Ru(II Complex Functionalized with cis-Dithiocyanato-bis-(9-anthracenyl-10-(2-methyl-2-butenoic acid-1,10-phenanthroline: Potential Sensitizer for Stable Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Adewale O. Adeloye

    2014-01-01

    Full Text Available New heteroleptic ruthenium(II complex was formulated as [Ru(L12(NCS2], where L1 = 9-anthracenyl-10-(2-methyl-2-butenoic acid-1,10-phenanthroline was synthesized and its photophysical properties were studied and compared to previously reported analogue complex containing no anthracene moiety [Ru(L22(NCS2], L2 = (2-methyl-2-butenoic acid-1,10-phenanthroline. The two complexes though exhibit very strong molar extinction coefficient values; however, [Ru(L12(NCS2] shows better characteristic broad and intense metal-to-ligand charge transfer (MLCT absorption band and higher molar absorptivity coefficient at (λmax=522 nm, ε=6.60×104 M−1 cm−1 than that of [Ru(L22(NCS2] complex, (λmax=446 nm, ε=4.82×104 M−1 cm−1. At room temperature, long wavelength emissions with strong intensity ratio centered at 660 nm were recorded for [Ru(L12(NCS2] complex with a bathochromic shift (λem=700 nm for [Ru(L22(NCS2] complex. It was shown that the luminescence wavelength characteristic of the complexes may be a function relating to the increasing length of π-conjugation and/or molecular weight. A preliminary cyclic voltammetry of [Ru(L12(NCS2] complex also exhibits good electroredox activity with oxidation potential of about 1.04 V, significantly better than other Ru(II polypyridine complexes containing bidentate ligands.

  6. The Sr:Ba:Rb ratio and zircon typology in granitoid complexes of Sao Paulo, Parana and Minas Gerais states (Brazil)

    International Nuclear Information System (INIS)

    Wernick, E.; Galembeck, T.M.B.; Artur, A.C.; Rigo Junior, L.; Weber-Diefenbach, K.

    1990-01-01

    Chemical (Sr: Ba: Rb) and zircon typology data from the Nazare Paulista, Mairipora/Cantareira, Cunhaporanga, Tres Corregos, Morungaba, Socorro, Itu, Graciosa and Serra Carambei granitoid complexes from the states of Minas Gerais, Sao Paulo and Parana (SE/S Brazil) are presented and discussed. By the zircon typology method these complexes are reffered, respectively, to the 2nd crustal, 3rd crustal/low temperature C-A, low temperature C-A, medium temperature C-A, medium/high temperature C-A, K-SA/Alkaline and alkaline serie which are considered as generated under increasing temperature associated with a progressive major participation of mantellic material. All these series, with the exception of the medium to high temperature calc-alkaline complexes Socorro and Morungaba whose chemical data come from several laboratories, display different positions and behaviour in the Sr: Ba: Rb diagram which reinforce the use of the zircon typology method in the study of granitoids. From the 2nd crustal serie up to the medium temperature C-A serie the complexes show a regular shift in their chemical composition which became progressively richer in Sr and depleted in Rb. The highly differentiades hypersolvus Serra do Carambei granite is strongly enriched in Rb and impoverish in Ba with respect to the Itu and the Graciosa complex which itself is slighly more depleted in Sr than the Itu granite. (author)

  7. Hospitals with greater diversities of physiologically complex procedures do not achieve greater surgical growth in a market with stable numbers of such procedures.

    Science.gov (United States)

    Dexter, Franklin; Epstein, Richard H; Lubarsky, David A

    2018-05-01

    Although having a large diversity of types of procedures has a substantial operational impact on the surgical suites of hospitals, the strategic importance is unknown. In the current study, we used longitudinal data for all hospitals and patient ages in the State of Florida to evaluate whether hospitals with greater diversity of types of physiologically complex major therapeutic procedures (PCMTP) also had greater rates of surgical growth. Observational cohort study. 1479 combinations of hospitals in the State of Florida and fiscal years, 2008-2015. The types of International Classification of Diseases, Ninth revision, Clinical Modification (ICD-9-CM) procedures studied were PCMT, defined as: a) major therapeutic procedure; b) >7 American Society of Anesthesiologists base units; and c) performed during a hospitalization with a Diagnosis Related Group with a mean length of stay ≥4.0days. The number of procedures of each type of PCMTP commonly performed at each hospital was calculated by taking 1/Herfindahl index (i.e., sum of the squares of the proportions of all procedures of each type of PCMTP). Over the 8 successive years studied, there was no change in the number of PCMTP being performed (Kendall's τ b =-0.014±0.017 [standard error], P=0.44; N=1479 hospital×years). Busier and larger hospitals commonly performed more types of PCMTP, respectively categorized based on performed PCMTP (τ=0.606±0.017, P<0.0001) or hospital beds (τ=0.524±0.017, P<0.0001). There was no association between greater diversity of types of PCMTP commonly performed and greater annual growth in numbers of PCMTP (τ=0.002±0.019, P=0.91; N=1295 hospital×years). Conclusions were the same with multiple sensitivity analyses. Post hoc, it was recognized that hospitals performing a greater diversity of PCMTP were more similar to the aggregate of other hospitals within the same health district (τ=0.550±0.017, P<0.0001). During a period with no overall growth in PCMTP, hospitals with

  8. Stable Isotope Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Tissue samples (skin, bone, blood, muscle) are analyzed for stable carbon, stable nitrogen, and stable sulfur analysis. Many samples are used in their entirety for...

  9. Synthesis and stereochemical assignments of diastereomeric Ni(II complexes of glycine Schiff base with (R-2-(N-{2-[N-alkyl-N-(1-phenylethylamino]acetyl}aminobenzophenone; a case of configurationally stable stereogenic nitrogen

    Directory of Open Access Journals (Sweden)

    Hiroki Moriwaki

    2014-02-01

    Full Text Available A family of chiral ligands derived from α-phenylethylamine and 2-aminobenzophenone were prepared by alkylation of the nitrogen atom. Upon reaction with glycine and a Ni(II salt, these ligands were transformed into diastereomeric complexes, as a result of the configurational stability of the stereogenic nitrogen atom. Different diastereomeric ratios were observed depending on the substituent R introduced in the starting ligand, and stereochemical assignments were based on X-ray analysis, along with NMR studies and optical rotation measurements.

  10. Analysis Ratio of Uranyl/Urea and Uranyl/HMTA on the ComplexesUranyl-Urea and Uranyl-HMTA with Spectrophotometry Method

    International Nuclear Information System (INIS)

    Simbolon, Sahat

    2000-01-01

    Reaction between uranyl and urea and uranyl and HMTA was investigated atpH = 4 and room temperature. The result of the reaction was measured withspectrophotometer, each absorbance was pictured between mol fraction andabsorbance for uranyl - urea and uranyl - HMTA. The linear and horizontalcurve was found for reaction uranyl - urea, meanwhile S curve for thereaction uranyl and HMTA. It was found that reaction between uranyl and HMTAon mol fraction value less than 0.25 was complexes meanwhile on the range of0.25 and 0.5 the reaction between uranyl and HMTA was stoichiometries.(author)

  11. Stable convergence and stable limit theorems

    CERN Document Server

    Häusler, Erich

    2015-01-01

    The authors present a concise but complete exposition of the mathematical theory of stable convergence and give various applications in different areas of probability theory and mathematical statistics to illustrate the usefulness of this concept. Stable convergence holds in many limit theorems of probability theory and statistics – such as the classical central limit theorem – which are usually formulated in terms of convergence in distribution. Originated by Alfred Rényi, the notion of stable convergence is stronger than the classical weak convergence of probability measures. A variety of methods is described which can be used to establish this stronger stable convergence in many limit theorems which were originally formulated only in terms of weak convergence. Naturally, these stronger limit theorems have new and stronger consequences which should not be missed by neglecting the notion of stable convergence. The presentation will be accessible to researchers and advanced students at the master's level...

  12. The Net Stable Funding Ratio; Impact and Issues for Consideration

    OpenAIRE

    Jeanne Gobat; Mamoru Yanase; Joseph Maloney

    2014-01-01

    As part of Basel III reforms, the NSFR is a new prudential liquidity rule aimed at limiting excess maturity transformation risk in the banking sector and promoting funding stability. The revised package has been issued for public consultation with a plan of making the rule binding in 2018. This paper complements earlier quantitative impact studies by discussing the potential impact of introducing the NSFR based on empirical analysis of end-2012 financial data for over 2000 banks covering 128 ...

  13. Stable carbon isotope ratios from archaeological charcoal as palaeoenvironmental indicators

    CSIR Research Space (South Africa)

    Hall, G

    2008-01-01

    Full Text Available specific pyrolysis products, mostly furans and pyrans, and released (Steinbeiss et al., 2006). The removal of these compounds is driven by their relative chemical stability and strength of molecular cross bonds. Differences between how... to simulate natural burning conditions and left until completely charred. This produced charcoal under oxidizing (O2-rich) conditions. This process took less than 15 min for the largest disc (60 mm in diameter) and about five minutes for the smallest (30...

  14. Manuring and stable nitrogen isotope ratios in cereals and pulses

    DEFF Research Database (Denmark)

    Fraser, Rebecca A; Bogaard, Amy; Heaton, Tim

    2011-01-01

    experiments and areas where ‘traditional’ farming is practised. Our aim is to ground-truth interpretation of δ15N values in archaeobotanical crop remains as evidence of past growing conditions and husbandry practices. The results confirm the potentially radical impact of manuring on δ15N values in cereals......, depending on manuring level, but indicate only a slight effect on pulses, which can fix atmospheric nitrogen. The expected geographical trend towards greater δ15N with increasing climatic aridity is not apparent, probably because the growing conditions for crops are ‘buffered’ through crop management. Each...... of these observations has fundamental implications for archaeobotanical interpretation of δ15N values as evidence of land use practices and (together with analysis of bone collagen/tooth enamel in potential consumers) palaeodiet....

  15. Lanthanide(III) complexes of a mono(methylphosphonate) analogue of H4dota: the influence of protonation of the phosphonate moiety on the TSAP/SAP isomer ratio and the water exchange rate.

    Science.gov (United States)

    Rudovský, Jakub; Cígler, Petr; Kotek, Jan; Hermann, Petr; Vojtísek, Pavel; Lukes, Ivan; Peters, Joop A; Vander Elst, Luce; Muller, Robert N

    2005-04-08

    A monophosphonate analogue of H4dota, 1,4,7,10-tetraazacyclododecane-4,7,10-tris(carboxymethyl)-1-methylphosphonic acid (H5do3aP), and its complexes with lanthanides were synthesized. Multinuclear NMR studies reveal that, in aqueous solution, lanthanide(III) complexes of the ligand exhibit structures analogous to those of H4dota complexes. Thus, the central ion is nine-coordinate, surrounded by four nitrogen atoms, three acetate and one phosphonate oxygen atoms, and one water molecule in an apical position. For complexes of H5do3aP with Ln(III) ions in the middle of the series, the abundance of the desired twisted square-antiprismatic (TSAP) isomer is higher than for the corresponding H4dota complexes. The TSAP/square-antiprismatic (SAP) isomer ratio is highly sensitive to protonation of the phosphonate group: a higher abundance of the TSAP isomer was found in acidic solutions. The microscopic protonation constants of the TSAP isomers are higher than those of the SAP isomers. The presence of one water molecule in the first coordination sphere of the complexes in the pH region studied (pH 2.5-7.0) is confirmed by 17O NMR spectroscopy. The results of a simultaneous fit of variable-temperature 17O NMR relaxation data and 1H NMRD profiles show that the residence time of water (tauM) in the Gd(III) complex is much smaller than for [Gd(dota)(H2O)]-. The exchange rate appears to be dependent on the pH of the solution. The values of tauM are 37, 40, and 14 ns at pH 2.5, 4.7, and 7.0, respectively. These observations can be explained by an extensive second-sphere hydrogen-bonding network that varies with the state of protonation of the phosphonate moiety. Upon protonation of the complex, the second-sphere hydration probably becomes more ordered, which may result in a decrease in penetrability and an increase in tauM. The relaxivity of the Gd(III) complex is almost independent of the pH and is equal to 4.7 s(-1) mM(-1) (20 MHz, pH 7 and 37 degrees C). The solid

  16. Magnesium stable isotope ecology using mammal tooth enamel

    Science.gov (United States)

    Martin, Jeremy E.; Vance, Derek; Balter, Vincent

    2015-01-01

    Geochemical inferences on ancient diet using bone and enamel apatite rely mainly on carbon isotope ratios (δ13C) and to a lesser extent on strontium/calcium (Sr/Ca) and barium/calcium (Ba/Ca) elemental ratios. Recent developments in nontraditional stable isotopes provide an unprecedented opportunity to use additional paleodietary proxies to disentangle complex diets such as omnivory. Of particular relevance for paleodietary reconstruction are metals present in large quantity in bone and enamel apatite, providing that biologically mediated fractionation processes are constrained. Calcium isotope ratios (δ44Ca) meet these criteria but exhibit complex ecological patterning. Stable magnesium isotope ratios (δ26Mg) also meet these criteria but a comprehensive understanding of its variability awaits new isotopic data. Here, 11 extant mammal species of known ecology from a single locality in equatorial Africa were sampled for tooth enamel and, together with vegetation and feces, analyzed for δ26Mg, δ13C, Sr/Ca, and Ba/Ca ratios. The results demonstrate that δ26Mg incorporated in tooth enamel becomes heavier from strict herbivores to omnivores/faunivores. Using data from experimentally raised sheep, we suggest that this 26Mg enrichment up the trophic chain is due to a 26Mg enrichment in muscle relative to bone. Notably, it is possible to distinguish omnivores from herbivores, using δ26Mg coupled to Ba/Ca ratios. The potential effects of metabolic and dietary changes on the enamel δ26Mg composition remain to be explored but, in the future, multiproxy approaches would permit a substantial refinement of dietary behaviors or enable accurate trophic reconstruction despite specimen-limited sampling, as is often the case for fossil assemblages.

  17. Using stable isotopes to monitor forms of sulfur during desulfurization processes: A quick screening method

    Science.gov (United States)

    Liu, Chao-Li; Hackley, Keith C.; Coleman, D.D.; Kruse, C.W.

    1987-01-01

    A method using stable isotope ratio analysis to monitor the reactivity of sulfur forms in coal during thermal and chemical desulfurization processes has been developed at the Illinois State Geological Survey. The method is based upon the fact that a significant difference exists in some coals between the 34S/32S ratios of the pyritic and organic sulfur. A screening method for determining the suitability of coal samples for use in isotope ratio analysis is described. Making these special coals available from coal sample programs would assist research groups in sorting out the complex sulfur chemistry which accompanies thermal and chemical processing of high sulfur coals. ?? 1987.

  18. Food and social complexity at Çayönü Tepesi, southeastern Anatolia: Stable isotope evidence of differentiation in diet according to burial practice and sex in the early Neolithic

    Science.gov (United States)

    Pearson, Jessica; Grove, Matt; Özbek, Metin; Hongo, Hitomi

    2013-01-01

    The identification of early social complexity and differentiation in early village societies has been approached in the past most notably through the evaluation of rituals and architectural layouts. Such studies could be complemented by an approach that provides data about everyday behaviours of individuals. We took 540 human and animal bone samples for stable carbon and nitrogen isotope analysis from the Neolithic site of Çayönü Tepesi in southeastern Anatolia. The inhabitants at this site chose to bury their dead in two different ways at different times during its occupation: beneath the floors of their houses, but also inside a public mortuary building known as the Skull Building. This variation provides an opportunity using isotope methods to test whether there was evidence for structuring of daily activities (diet in this case) that might serve to reinforce this change in burial practice. We show that when the inhabitants of Çayönü Tepesi changed their architecture and operated different burial practices in conjunction, this coincided with other aspects of behaviour including socially-constituted food consumption practices, which served to reinforce social identities. PMID:24976671

  19. stableGP

    Data.gov (United States)

    National Aeronautics and Space Administration — The code in the stableGP package implements Gaussian process calculations using efficient and numerically stable algorithms. Description of the algorithms is in the...

  20. Angina Pectoris (Stable Angina)

    Science.gov (United States)

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Angina Pectoris (Stable Angina) Updated:Aug 21,2017 You may have heard the term “angina pectoris” or “stable angina” in your doctor’s office, ...

  1. Elemental ratios for characterization of quantum-dots populations in complex mixtures by asymmetrical flow field-flow fractionation on-line coupled to fluorescence and inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Menendez-Miranda, Mario; Fernandez-Arguelles, Maria T.; Costa-Fernandez, Jose M.; Encinar, Jorge Ruiz; Sanz-Medel, Alfredo

    2014-01-01

    Highlights: • The hyphenated system allows unequivocal identification of nanoparticle populations. • AF4 separation permitted detection of unexpected nanosized species in a sample. • ICP-QQQ provides elemental ratios with adequate accuracy in every nanoparticle. • Purity and chemical composition of different quantum dot samples were assessed. - Abstract: Separation and identification of nanoparticles of different composition, with similar particle diameter, coexisting in heterogeneous suspensions of polymer-coated CdSe/ZnS quantum dots (QDs) have been thoroughly assessed by asymmetric flow field-flow fractionation (AF4) coupled on-line to fluorescence and inductively coupled plasma mass spectrometry (ICPMS) detectors. Chemical characterization of any previously on-line separated nanosized species was achieved by the measurement of the elemental molar ratios of every element involved in the synthesis of the QDs, using inorganic standards and external calibration by flow injection analysis (FIA). Such elemental molar ratios, strongly limited so far to pure single nanoparticles suspensions, have been achieved with adequate accuracy by coupling for the first time an ICP-QQQ instrument to an AF4 system. This hyphenation turned out to be instrumental to assess the chemical composition of the different populations of nanoparticles coexisting in the relatively complex mixtures, due to its capabilities to detect the hardly detectable elements involved in the synthesis. Interestingly such information, complementary to that obtained by fluorescence, was very valuable to detect and identify unexpected nanosized species, present at significant level, produced during QDs synthesis and hardly detectable by standard approaches

  2. Periodicity of the stable isotopes

    CERN Document Server

    Boeyens, J C A

    2003-01-01

    It is demonstrated that all stable (non-radioactive) isotopes are formally interrelated as the products of systematically adding alpha particles to four elementary units. The region of stability against radioactive decay is shown to obey a general trend based on number theory and contains the periodic law of the elements as a special case. This general law restricts the number of what may be considered as natural elements to 100 and is based on a proton:neutron ratio that matches the golden ratio, characteristic of biological and crystal growth structures. Different forms of the periodic table inferred at other proton:neutron ratios indicate that the electronic configuration of atoms is variable and may be a function of environmental pressure. Cosmic consequences of this postulate are examined. (author)

  3. Stable isotope ratios of marijuana. I. Carbon and nitrogen stable isotopes describe growth conditions.

    Science.gov (United States)

    West, Jason B; Hurley, Janet M; Ehleringer, James R

    2009-01-01

    There remains significant uncertainty in illicit marijuana cultivation. We analyzed the delta(13)C and delta(15)N of 508 domestic samples from known U.S.A. counties, 31 seized from a single location, 5 samples grown in Mexico and Colombia, and 10 northwest border seizures. For a subset, inflorescences and leaves were analyzed separately. These data revealed a strong correspondence, with inflorescences having slightly higher delta(13)C and delta(15)N values than leaves. A framework for interpreting these results is introduced and evaluated. Samples identified as outdoor-grown by delta(13)C were generally recorded as such by the Drug Enforcement Administration (DEA). DEA-classified indoor-grown samples had the most negative delta(13)C values, consistent with indoor cultivation, although many were also in the outdoor-grown domain. Delta(15)N indicated a wide range of fertilizers across the dataset. Samples seized at the single location suggested multiple sources. Northwest border delta(13)C values suggested indoor growth, whereas for the Mexican and Colombian samples they indicated outdoor growth.

  4. Kinetic stable Cr isotopic fractionation between aqueous Cr(III)-Cl-H2O complexes at 25 °C: Implications for Cr(III) mobility and isotopic variations in modern and ancient natural systems

    Science.gov (United States)

    Babechuk, Michael G.; Kleinhanns, Ilka C.; Reitter, Elmar; Schoenberg, Ronny

    2018-02-01

    dissolution of two Cr(III)-Cl solids (dried NIST SRM979 standard and commercial CrCl3·6H2O salt) in 0.01 M HCl (pH ≈ 2). The ε53/52Cr(CrCl2+/CrCl2+) for the CrCl2+ to CrCl2+ reaction is -0.19‰ (SRM979) and -0.38‰ (salt) and the ε53/52Cr(Cr3+/CrCl2+) for the CrCl2+ to Cr3+ reaction is consistent for both experiments at -0.49‰ (SRM979) and -0.51‰ (salt). Experiments where SRM979 is dissolved in 0.1 and 1 M HCl for a longer aging period provide preliminary evidence that the Cr3+/CrCl2+ Cr(III) isotopic fractionation scales with HCl concentration (transformation rate). Chromium(III) dissolved in 6 M HCl and aged 5 months still yields an inter-species Cr isotope distribution that is apparently inherited from kinetic effects (light Cr isotopes in Cr3+), attesting to the slow development of inter-species isotopic equilibrium, which instead predicts progressively heavier Cr isotopes from CrCl2+ to CrCl2+ to Cr3+. The kinetic Cr(III) isotopic fractionation documented herein is proposed to be relevant to understanding systems where aqueous Cr(III)-Cl species may be temporarily stable (e.g., metamorphic and hydrothermal systems or lateritic weathering). Further, the complexation of Cr(III) with other ligands (e.g., CO32-, organics), combined with additional kinetic effects of Cr(III) potentially occurring in soils or sediment, must be explored prior to establishing the significance of empirical stable Cr isotope signatures in marine and continental environments. Further understanding of non-redox effects may lead to stable Cr isotopes developing as a proxy for system pH or ligand chemistry.

  5. UNiquant, a Program for Quantitative Proteomics Analysis Using Stable Isotope Labeling

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xin; Tolmachev, Aleksey V.; Shen, Yulei; Liu, Miao; Huang, Lin; Zhang, Zhixin; Anderson, Gordon A.; Smith, Richard D.; Chan, Wing C.; Hinrichs, Steven; Fu, Kai; Ding, Shi-Jian

    2011-03-04

    We present UNiquant, a new software program for analyzing stable isotope labeling (SIL) based quantitative proteomics data. UNiquant surpassed the performance of two other platforms, MaxQuant and Mascot Distiller, using complex proteome mixtures having either known or unknown heavy/light ratios. UNiquant is compatible with a broad spectrum of search engines and SIL methods, providing outstanding peptide pair identification and accurate measurement of the relative peptide/protein abundance.

  6. Stable Boundary Layer Issues

    OpenAIRE

    Steeneveld, G.J.

    2012-01-01

    Understanding and prediction of the stable atmospheric boundary layer is a challenging task. Many physical processes are relevant in the stable boundary layer, i.e. turbulence, radiation, land surface coupling, orographic turbulent and gravity wave drag, and land surface heterogeneity. The development of robust stable boundary layer parameterizations for use in NWP and climate models is hampered by the multiplicity of processes and their unknown interactions. As a result, these models suffer ...

  7. Stable isotopes labelled compounds

    International Nuclear Information System (INIS)

    1982-09-01

    The catalogue on stable isotopes labelled compounds offers deuterium, nitrogen-15, and multiply labelled compounds. It includes: (1) conditions of sale and delivery, (2) the application of stable isotopes, (3) technical information, (4) product specifications, and (5) the complete delivery programme

  8. Evolutionary Stable Strategy

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 21; Issue 9. Evolutionary Stable Strategy: Application of Nash Equilibrium in Biology. General Article Volume 21 Issue 9 September 2016 pp 803- ... Keywords. Evolutionary game theory, evolutionary stable state, conflict, cooperation, biological games.

  9. Stable Boundary Layer Issues

    NARCIS (Netherlands)

    Steeneveld, G.J.

    2012-01-01

    Understanding and prediction of the stable atmospheric boundary layer is a challenging task. Many physical processes are relevant in the stable boundary layer, i.e. turbulence, radiation, land surface coupling, orographic turbulent and gravity wave drag, and land surface heterogeneity. The

  10. Elemental ratios for characterization of quantum-dots populations in complex mixtures by asymmetrical flow field-flow fractionation on-line coupled to fluorescence and inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Menendez-Miranda, Mario; Fernandez-Arguelles, Maria T; Costa-Fernandez, Jose M; Encinar, Jorge Ruiz; Sanz-Medel, Alfredo

    2014-08-11

    Separation and identification of nanoparticles of different composition, with similar particle diameter, coexisting in heterogeneous suspensions of polymer-coated CdSe/ZnS quantum dots (QDs) have been thoroughly assessed by asymmetric flow field-flow fractionation (AF4) coupled on-line to fluorescence and inductively coupled plasma mass spectrometry (ICPMS) detectors. Chemical characterization of any previously on-line separated nanosized species was achieved by the measurement of the elemental molar ratios of every element involved in the synthesis of the QDs, using inorganic standards and external calibration by flow injection analysis (FIA). Such elemental molar ratios, strongly limited so far to pure single nanoparticles suspensions, have been achieved with adequate accuracy by coupling for the first time an ICP-QQQ instrument to an AF4 system. This hyphenation turned out to be instrumental to assess the chemical composition of the different populations of nanoparticles coexisting in the relatively complex mixtures, due to its capabilities to detect the hardly detectable elements involved in the synthesis. Interestingly such information, complementary to that obtained by fluorescence, was very valuable to detect and identify unexpected nanosized species, present at significant level, produced during QDs synthesis and hardly detectable by standard approaches. Copyright © 2014. Published by Elsevier B.V.

  11. Normal modified stable processes

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole Eiler; Shephard, N.

    2002-01-01

    Gaussian (NGIG) laws. The wider framework thus established provides, in particular, for added flexibility in the modelling of the dynamics of financial time series, of importance especially as regards OU based stochastic volatility models for equities. In the special case of the tempered stable OU process......This paper discusses two classes of distributions, and stochastic processes derived from them: modified stable (MS) laws and normal modified stable (NMS) laws. This extends corresponding results for the generalised inverse Gaussian (GIG) and generalised hyperbolic (GH) or normal generalised inverse...

  12. Applications of stable isotopes

    International Nuclear Information System (INIS)

    Letolle, R.; Mariotti, A.; Bariac, T.

    1991-06-01

    This report reviews the historical background and the properties of stable isotopes, the methods used for their measurement (mass spectrometry and others), the present technics for isotope enrichment and separation, and at last the various present and foreseeable application (in nuclear energy, physical and chemical research, materials industry and research; tracing in industrial, medical and agronomical tests; the use of natural isotope variations for environmental studies, agronomy, natural resources appraising: water, minerals, energy). Some new possibilities in the use of stable isotope are offered. A last chapter gives the present state and forecast development of stable isotope uses in France and Europe

  13. Stability of low aspect ratio inverted flags and rods in a uniform flow

    Science.gov (United States)

    Huertas-Cerdeira, Cecilia; Sader, John E.; Gharib, Morteza

    2016-11-01

    Cantilevered elastic plates and rods in an inverted configuration, where the leading edge is free to move and the trailing edge is clamped, undergo complex dynamics when subjected to a uniform flow. The stability of low aspect ratio inverted plates and rods is theoretically examined, showing that it is markedly different from that of their large aspect ratio counterpart. In the limit of zero aspect ratio, the undeflected equilibrium position is found to be stable for all wind speeds. A saddle-node bifurcation emerges at finite wind speed, giving rise to a strongly deflected stable and a weakly deflected unstable equilibria. This theory is compared to experimental measurements, where good agreement is found. This research was supported by a Grant of the Gordon and Betty Moore Foundation, the Australian Research Council Grants scheme and a "la Caixa" Fellowship Grant for Post-Graduate Studies of "la Caixa" Banking Foundation.

  14. Analysing Stable Time Series

    National Research Council Canada - National Science Library

    Adler, Robert

    1997-01-01

    We describe how to take a stable, ARMA, time series through the various stages of model identification, parameter estimation, and diagnostic checking, and accompany the discussion with a goodly number...

  15. Low-peak-to-average power ratio and low-complexity asymmetrically clipped optical orthogonal frequency-division multiplexing uplink transmission scheme for long-reach passive optical network.

    Science.gov (United States)

    Zhou, Ji; Qiao, Yaojun

    2015-09-01

    In this Letter, we propose a discrete Hartley transform (DHT)-spread asymmetrically clipped optical orthogonal frequency-division multiplexing (DHT-S-ACO-OFDM) uplink transmission scheme in which the multiplexing/demultiplexing process also uses the DHT algorithm. By designing a simple encoding structure, the computational complexity of the transmitter can be reduced from O(Nlog(2)(N)) to O(N). At the probability of 10(-3), the peak-to-average power ratio (PAPR) of 2-ary pulse amplitude modulation (2-PAM)-modulated DHT-S-ACO-OFDM is approximately 9.7 dB lower than that of 2-PAM-modulated conventional ACO-OFDM. To verify the feasibility of the proposed scheme, a 4-Gbit/s DHT-S-ACO-OFDM uplink transmission scheme with a 1∶64 way split has been experimentally implemented using 100-km standard single-mode fiber (SSMF) for a long-reach passive optical network (LR-PON).

  16. Calcium stable isotope geochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Gausonne, Nikolaus [Muenster Univ. (Germany). Inst. fuer Mineralogie; Schmitt, Anne-Desiree [Strasbourg Univ. (France). LHyGeS/EOST; Heuser, Alexander [Bonn Univ. (Germany). Steinmann-Inst. fuer Geologie, Mineralogie und Palaeontologie; Wombacher, Frank [Koeln Univ. (Germany). Inst. fuer Geologie und Mineralogie; Dietzel, Martin [Technische Univ. Graz (Austria). Inst. fuer Angewandte Geowissenschaften; Tipper, Edward [Cambridge Univ. (United Kingdom). Dept. of Earth Sciences; Schiller, Martin [Copenhagen Univ. (Denmark). Natural History Museum of Denmark

    2016-08-01

    This book provides an overview of the fundamentals and reference values for Ca stable isotope research, as well as current analytical methodologies including detailed instructions for sample preparation and isotope analysis. As such, it introduces readers to the different fields of application, including low-temperature mineral precipitation and biomineralisation, Earth surface processes and global cycling, high-temperature processes and cosmochemistry, and lastly human studies and biomedical applications. The current state of the art in these major areas is discussed, and open questions and possible future directions are identified. In terms of its depth and coverage, the current work extends and complements the previous reviews of Ca stable isotope geochemistry, addressing the needs of graduate students and advanced researchers who want to familiarize themselves with Ca stable isotope research.

  17. Calcium stable isotope geochemistry

    International Nuclear Information System (INIS)

    Gausonne, Nikolaus; Schmitt, Anne-Desiree; Heuser, Alexander; Wombacher, Frank; Dietzel, Martin; Tipper, Edward; Schiller, Martin

    2016-01-01

    This book provides an overview of the fundamentals and reference values for Ca stable isotope research, as well as current analytical methodologies including detailed instructions for sample preparation and isotope analysis. As such, it introduces readers to the different fields of application, including low-temperature mineral precipitation and biomineralisation, Earth surface processes and global cycling, high-temperature processes and cosmochemistry, and lastly human studies and biomedical applications. The current state of the art in these major areas is discussed, and open questions and possible future directions are identified. In terms of its depth and coverage, the current work extends and complements the previous reviews of Ca stable isotope geochemistry, addressing the needs of graduate students and advanced researchers who want to familiarize themselves with Ca stable isotope research.

  18. Stable isotope studies

    International Nuclear Information System (INIS)

    Ishida, T.

    1992-01-01

    The research has been in four general areas: (1) correlation of isotope effects with molecular forces and molecular structures, (2) correlation of zero-point energy and its isotope effects with molecular structure and molecular forces, (3) vapor pressure isotope effects, and (4) fractionation of stable isotopes. 73 refs, 38 figs, 29 tabs

  19. Interactive Stable Ray Tracing

    DEFF Research Database (Denmark)

    Dal Corso, Alessandro; Salvi, Marco; Kolb, Craig

    2017-01-01

    Interactive ray tracing applications running on commodity hardware can suffer from objectionable temporal artifacts due to a low sample count. We introduce stable ray tracing, a technique that improves temporal stability without the over-blurring and ghosting artifacts typical of temporal post-pr...

  20. The Stable Concordance Genus

    OpenAIRE

    Kearney, M. Kate

    2013-01-01

    The concordance genus of a knot is the least genus of any knot in its concordance class. Although difficult to compute, it is a useful invariant that highlights the distinction between the three-genus and four-genus. In this paper we define and discuss the stable concordance genus of a knot, which describes the behavior of the concordance genus under connected sum.

  1. Stable radiographic scanning agents

    International Nuclear Information System (INIS)

    1976-01-01

    Stable compositions which are useful in the preparation of Technetium-99m-based scintigraphic agents are discussed. They are comprised of ascorbic acid or a pharmaceutically acceptable salt or ester thereof in combination with a pertechnetate reducing agent or dissolved in oxidized pertechnetate-99m (sup(99m)TcO 4 - ) solution

  2. Some stable hydromagnetic equilibria

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J L; Oberman, C R; Kulsrud, R M; Frieman, E A [Project Matterhorn, Princeton University, Princeton, NJ (United States)

    1958-07-01

    We have been able to find and investigate the properties of equilibria which are hydromagnetically stable. These equilibria can be obtained, for example, by wrapping conductors helically around the stellarator tube. Systems with I = 3 or 4 are indicated to be optimum for stability purposes. In some cases an admixture of I = 2 fields can be advantageous for achieving equilibrium. (author)

  3. 26 S proteasomes function as stable entities

    DEFF Research Database (Denmark)

    Hendil, Klavs B; Hartmann-Petersen, Rasmus; Tanaka, Keiji

    2002-01-01

    , shuttles between a free state and the 26-S proteasome, bringing substrate to the complex. However, S5a was not found in the free state in HeLa cells. Besides, all subunits in PA700, including S5a, exchanged at similar low rates. It therefore seems that 26-S proteasomes function as stable entities during...

  4. Faster and Simpler Approximation of Stable Matchings

    Directory of Open Access Journals (Sweden)

    Katarzyna Paluch

    2014-04-01

    Full Text Available We give a 3 2 -approximation algorithm for finding stable matchings that runs in O(m time. The previous most well-known algorithm, by McDermid, has the same approximation ratio but runs in O(n3/2m time, where n denotes the number of people andm is the total length of the preference lists in a given instance. In addition, the algorithm and the analysis are much simpler. We also give the extension of the algorithm for computing stable many-to-many matchings.

  5. Stable isotope analysis

    International Nuclear Information System (INIS)

    Tibari, Elghali; Taous, Fouad; Marah, Hamid

    2014-01-01

    This report presents results related to stable isotopes analysis carried out at the CNESTEN DASTE in Rabat (Morocco), on behalf of Senegal. These analyzes cover 127 samples. These results demonstrate that Oxygen-18 and Deuterium in water analysis were performed by infrared Laser spectroscopy using a LGR / DLT-100 with Autosampler. Also, the results are expressed in δ values (‰) relative to V-SMOW to ± 0.3 ‰ for oxygen-18 and ± 1 ‰ for deuterium.

  6. Forensic Stable Isotope Biogeochemistry

    Science.gov (United States)

    Cerling, Thure E.; Barnette, Janet E.; Bowen, Gabriel J.; Chesson, Lesley A.; Ehleringer, James R.; Remien, Christopher H.; Shea, Patrick; Tipple, Brett J.; West, Jason B.

    2016-06-01

    Stable isotopes are being used for forensic science studies, with applications to both natural and manufactured products. In this review we discuss how scientific evidence can be used in the legal context and where the scientific progress of hypothesis revisions can be in tension with the legal expectations of widely used methods for measurements. Although this review is written in the context of US law, many of the considerations of scientific reproducibility and acceptance of relevant scientific data span other legal systems that might apply different legal principles and therefore reach different conclusions. Stable isotopes are used in legal situations for comparing samples for authenticity or evidentiary considerations, in understanding trade patterns of illegal materials, and in understanding the origins of unknown decedents. Isotope evidence is particularly useful when considered in the broad framework of physiochemical processes and in recognizing regional to global patterns found in many materials, including foods and food products, drugs, and humans. Stable isotopes considered in the larger spatial context add an important dimension to forensic science.

  7. A theory of stable-isotope dilution mass spectrometry

    International Nuclear Information System (INIS)

    Pickup, J.F.; McPherson, C.K.

    1977-01-01

    In order to perform quantitative analysis using stable isotope dilution with mass spectrometry, an equation is derived which describes the relationship between the relative proportions of natural and labelled material and measured isotope ratios

  8. Substrate-induced stable enzyme-inhibitor complex formation allows tight binding of novel 2-aminopyrimidin-4(3H)-ones to drug-resistant HIV-1 reverse transcriptase mutants.

    Science.gov (United States)

    Samuele, Alberta; Facchini, Marcella; Rotili, Dante; Mai, Antonello; Artico, Marino; Armand-Ugón, Mercedes; Esté, José A; Maga, Giovanni

    2008-09-01

    We recently reported the synthesis and biological evaluation of a novel series of 5-alkyl-2-(N,N-disubstituted)amino-6-(2,6-difluorophenylalkyl)-3,4-dihydropyrimidin-4(3H)-ones (F(2)-N,N-DABOs). These compounds are highly active against both wild-type HIV-1 and the K103N, Y181C, and Y188L mutant strains. Herein we present novel 6-(2-chloro-6-fluorophenylalkyl)-N,N-DABO (2-Cl-6-F-N,N-DABO) derivatives and investigate the molecular basis for their high-affinity binding to HIV-1 reverse transcriptase (RT). Our results show that the new compounds display higher association rates than the difluoro derivatives toward wild-type HIV-1 RT or drug-resistant RT mutant forms. We also show that they preferentially associate to either the free enzyme or the enzyme-nucleic acid binary complex, and that this binding is stabilized upon formation of the ternary complex between HIV-1 RT and both the nucleic acid and nucleotide substrates. Interestingly, one compound showed dissociation rates from the ternary complex with RT mutants K103N and Y181I 10-20-fold slower than from the corresponding complex with wild-type RT.

  9. Synthesis and characterization of thermally stable oligomer-metal ...

    African Journals Online (AJOL)

    The thermal stabilities of the oligomer-metal complexes were compared by thermogravimetric (TG) and differential thermal (DTA) analyses. According to TG, oligomer-metal complexes were stable against to temperature and thermooxidative decomposition. The weight losses of oligomer-metal complexes were found to be 5 ...

  10. The Stable Diiron (2.5) Complex Ion [(NC).sub.5./sub.Fe(ć-tz)Fe(CN).sub.5./sub.].sup.5-./sup., tz=1,2,4,5-Tetrazine, and Its Neighboring Oxidation States

    Czech Academy of Sciences Publication Activity Database

    Glöckle, M.; Kaim, W.; Klein, A.; Roduner, E.; Hübner, G.; Záliš, Stanislav; Slageren van, J.; Renz, F.; Gütlich, P.

    2001-01-01

    Roč. 40, č. 10 (2001), s. 2256-2262 ISSN 0020-1669 R&D Projects: GA MŠk OC D14.20; GA MŠk OC D15.10 Institutional research plan: CEZ:AV0Z4040901 Keywords : mixed valent compound * diiron tetrazine complex * spectroelectrochemistry Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.946, year: 2001

  11. Stability and properties of quasi-stable conformational states in the LH2 light-harvesting complex of Rbl. acidophilus bacteria formed by hexacoordination of bacteriochlorophyll a magnesium atom

    Science.gov (United States)

    Belov, Aleksandr S.; Khokhlov, Daniil V.; Glebov, Ilya O.; Poddubnyy, Vladimir V.; Eremin, Vadim V.

    2017-06-01

    Single-molecule spectroscopic experiments on several light-harvesting complexes revealed the existence of a set of metastable conformational states with different spectroscopic properties and lifetimes spanning from milliseconds to tens of seconds. In the absence of explicit structural data, a number of probable structural changes underlying the observed spectroscopic shifts were proposed. We examine the donor-acceptor interaction between the magnesium atom and the acetyl group of the adjacent bacteriochlorophylls a as a possible origin of metastable conformational states in the LH2 light-harvesting complex of Rbl. acidophilus bacteria. The results of QM/MM and molecular dynamics simulations show that such ligation can occur at room temperature and leads to one metastable coordination bond per pair of bacteriochlorophylls in the B850 ring. According to the results of Poisson-TrESP modeling, such coordination lowers the energies of the excited states of the complex by up to 163 cm-1 which causes red spectral shift of the B850 band.

  12. Formulation of stable protein powders by supercritical fluid drying

    NARCIS (Netherlands)

    Jovanović, N.

    2007-01-01

    Protein pharmaceuticals are potent drugs for the treatment of several chronic and life-threatening diseases. However, the complex and sensitive nature of protein molecules requires special attention in the development of stable dosage forms. Developing stable aqueous protein formulations is often a

  13. Financial Key Ratios

    OpenAIRE

    Tănase Alin-Eliodor

    2014-01-01

    This article focuses on computing techniques starting from trial balance data regarding financial key ratios. There are presented activity, liquidity, solvency and profitability financial key ratios. It is presented a computing methodology in three steps based on a trial balance.

  14. Theory of stable allocations

    Directory of Open Access Journals (Sweden)

    Pantelić Svetlana

    2014-01-01

    Full Text Available The Swedish Royal Academy awarded the 2012 Nobel Prize in Economics to Lloyd Shapley and Alvin Roth, for the theory of stable allocations and the practice of market design. These two American researchers worked independently from each other, combining basic theory and empirical investigations. Through their experiments and practical design they generated a flourishing field of research and improved the performance of many markets. Born in 1923 in Cambridge, Massachusetts, Shapley defended his doctoral thesis at Princeton University in 1953. For many years he worked at RAND, and for more than thirty years he was a professor at UCLA University. He published numerous scientific papers, either by himself or in cooperation with other economists.

  15. The status of applying stable isotope in the studies of environmental science

    International Nuclear Information System (INIS)

    Bai Zhipeng; Zhang Liwen; Zhu Tan; Feng Yinchang

    2007-01-01

    The stable isotope composition is characteristic in the pollution source, and it is relatively fixed in the process of transferring and reaction. At present the precise analysis result of stable isotope ratio can be obtained easily. So the stable isotopes can be applied to the pollution affair arbitration and source study. The concept and analytical method of stable isotopes are introduced. The research status of the stable isotopes in the field of environmental science and the isotope fractionation is reviewed. (authors)

  16. Exact simulation of max-stable processes.

    Science.gov (United States)

    Dombry, Clément; Engelke, Sebastian; Oesting, Marco

    2016-06-01

    Max-stable processes play an important role as models for spatial extreme events. Their complex structure as the pointwise maximum over an infinite number of random functions makes their simulation difficult. Algorithms based on finite approximations are often inexact and computationally inefficient. We present a new algorithm for exact simulation of a max-stable process at a finite number of locations. It relies on the idea of simulating only the extremal functions, that is, those functions in the construction of a max-stable process that effectively contribute to the pointwise maximum. We further generalize the algorithm by Dieker & Mikosch (2015) for Brown-Resnick processes and use it for exact simulation via the spectral measure. We study the complexity of both algorithms, prove that our new approach via extremal functions is always more efficient, and provide closed-form expressions for their implementation that cover most popular models for max-stable processes and multivariate extreme value distributions. For simulation on dense grids, an adaptive design of the extremal function algorithm is proposed.

  17. Bi-stable optical actuator

    Science.gov (United States)

    Holdener, Fred R.; Boyd, Robert D.

    2000-01-01

    The present invention is a bi-stable optical actuator device that is depowered in both stable positions. A bearing is used to transfer motion and smoothly transition from one state to another. The optical actuator device may be maintained in a stable position either by gravity or a restraining device.

  18. The antibiotic tiamulin is a potent inducer and inhibitor of cytochrome P4503A via the formation of a stable metabolic intermediate complex. Studies in primary hepatocyte cultures and liver microsomes of the pig.

    Science.gov (United States)

    Witkamp, R F; Nijmeijer, S M; Monshouwer, M; Van Miert, A S

    1995-05-01

    Tiamulin is a semisynthetic antibiotic frequently used in agricultural animals. The drug has been shown to produce clinically important--often lethal--interactions with other compounds that are simultaneously administered. To explain this, it has been suggested that tiamulin selectively inhibits oxidative drug metabolism via the formation of a cytochrome P450 metabolic intermediate complex. The aim of the present study was to provide further support for this hypothesis. When hepatic microsomes and cultured primary pig hepatocytes were incubated with tiamulin, a maximum in the absorbance spectrum at 455 nm was observed, which disappeared after adding KFe(CN)6. When hepatocytes were incubated with tiamulin for 72 hr, cytochrome P450 content and cytochrome P4503A apoprotein levels were increased. Tiamulin strongly inhibited and concentration dependently inhibited the hydroxylation rate of testosterone at the 6 beta-position in both microsomes and hepatocytes, and the microsomal N-demethylation rate of ethylmorphine. Other testosterone hydroxylations were inhibited to a lesser extent or not affected. The relative inhibition of the hydroxylation of testosterone at the 6 beta-position was more pronounced in microsomes from rifampicin- and triacetyloleandomycin-treated pigs. The results indicate that cytochrome P450 complex formation can at least partly explain the interactions observed with tiamulin. Tiamulin seems to be a strong, probably selective, inhibitor of the cytochrome P4503A subfamily and an interesting tool for further research.

  19. Nuclear fuel, mass balances, conversion ratio, doubling time, and uncertainty

    International Nuclear Information System (INIS)

    Vondy, D.R.

    1976-11-01

    Information on the performance aspects of nuclear power plants is presented concerning conversion ratio, criticality, primitive economic analysis, stable breeder-converter industry, doubling time, breeder industry economic benefit, defining nuclear fuel, recommendations, and uncertainty

  20. VVER-1000 dominance ratio

    International Nuclear Information System (INIS)

    Gorodkov, S.

    2009-01-01

    Dominance ratio, or more precisely, its closeness to unity, is important characteristic of large reactor. It allows evaluate beforehand the number of source iterations required in deterministic calculations of power spatial distribution. Or the minimal number of histories to be modeled for achievement of statistical error level desired in large core Monte Carlo calculations. In this work relatively simple approach for dominance ratio evaluation is proposed. It essentially uses core symmetry. Dependence of dominance ratio on neutron flux spatial distribution is demonstrated. (author)

  1. WWER-1000 dominance ratio

    International Nuclear Information System (INIS)

    Gorodkov, S.S.

    2009-01-01

    Dominance ratio, or more precisely, its closeness to unity, is important characteristic of large reactor. It allows evaluate beforehand the number of source iterations required in deterministic calculations of power spatial distribution. Or the minimal number of histories to be modeled for achievement of statistical error level desired in large core Monte Carlo calculations. In this work relatively simple approach for dominance ratio evaluation is proposed. It essentially uses core symmetry. Dependence of dominance ratio on neutron flux spatial distribution is demonstrated. (Authors)

  2. Separation of polybrominated diphenyl ethers in fish for compound-specific stable carbon isotope analysis

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Yan-Hong [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Graduate University of Chinese Academy of Sciences, Beijing, 100049 (China); Luo, Xiao-Jun, E-mail: luoxiaoj@gig.ac.cn [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Chen, Hua-Shan; Wu, Jiang-Ping; Chen, She-Jun; Mai, Bi-Xian [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China)

    2012-05-15

    A separation and isotopic analysis method was developed to accurately measure the stable carbon isotope ratios of polybrominated diphenyl ethers (PBDEs) with three to six substituted bromine atoms in fish samples. Sample extracts were treated with concentrated sulfuric acid to remove lipids, purified using complex silica gel column chromatography, and finally processed using alumina/silica (Al/Si) gel column chromatography. The purities of extracts were verified by gas chromatography and mass spectrometry (GC-MS) in the full-scan mode. The average recoveries of all compounds across the purification method were between 60% and 110%, with the exception of BDE-154. The stable carbon isotopic compositions of PBDEs can be measured with a standard deviation of less than 0.5 Per-Mille-Sign . No significant isotopic fraction was found during the purification of the main PBDE congeners. A significant change in the stable carbon isotope ratio of BDE-47 was observed in fish carcasses compared to the original isotopic signatures, implying that PBDE stable carbon isotopic compositions can be used to trace the biotransformation of PBDEs in biota. - Highlights: Black-Right-Pointing-Pointer A method for the purification of PBDEs for CSIA was developed. Black-Right-Pointing-Pointer The {delta}{sup 13}C of PBDE congeners can be measured with a standard deviation of less than 0.5 Per-Mille-Sign . Black-Right-Pointing-Pointer Common carp were exposed to a PBDE mixture to investigate debromination. Black-Right-Pointing-Pointer Ratios of the {delta}{sup 13}C values can be used to trace the debromination of PBDE in fish.

  3. Structure of stable degeneration of K3 surfaces into pairs of rational elliptic surfaces

    OpenAIRE

    Kimura, Yusuke

    2018-01-01

    F-theory/heterotic duality is formulated in the stable degeneration limit of a K3 fibration on the F-theory side. In this note, we analyze the structure of the stable degeneration limit. We discuss whether stable degeneration exists for pairs of rational elliptic surfaces. We demonstrate that, when two rational elliptic surfaces have an identical complex structure, stable degeneration always exists. We provide an equation that systematically describes the stable degeneration of a K3 surface i...

  4. Stable Structures for Distributed Applications

    Directory of Open Access Journals (Sweden)

    Eugen DUMITRASCU

    2008-01-01

    Full Text Available For distributed applications, we define the linear, tree and graph structure types with different variants and modalities to aggregate them. The distributed applications have assigned structures that through their characteristics influence the costs of stages for developing cycle and the costs for exploitation, transferred to each user. We also present the quality characteristics of a structure for a stable application, which is focused on stability characteristic. For that characteristic we define the estimated measure indicators for a level. The influence of the factors of stability and the ways for increasing it are thus identified, and at the same time the costs of development stages, the costs of usage and the costs of maintenance to be keep on between limits that assure the global efficiency of application. It is presented the base aspects for distributed applications: definition, peculiarities and importance. The aspects for the development cycle of distributed application are detailed. In this article, we alongside give the mechanisms for building the defined structures and analyze the complexity of the defined structures for a distributed application of a virtual store.

  5. Sharpening Sharpe Ratios

    OpenAIRE

    William N. Goetzmann; Jonathan E. Ingersoll Jr.; Matthew I. Spiegel; Ivo Welch

    2002-01-01

    It is now well known that the Sharpe ratio and other related reward-to-risk measures may be manipulated with option-like strategies. In this paper we derive the general conditions for achieving the maximum expected Sharpe ratio. We derive static rules for achieving the maximum Sharpe ratio with two or more options, as well as a continuum of derivative contracts. The optimal strategy has a truncated right tail and a fat left tail. We also derive dynamic rules for increasing the Sharpe ratio. O...

  6. Organic carbon and nitrogen stable isotopes in the intertidal sediments from the Yangtze Estuary, China

    International Nuclear Information System (INIS)

    Liu, M. . E-mail mliu@geo.ecnu.edu.cn; Hou, L.J.; Xu, S.Y.; Ou, D.N.; Yang, Y.; Yu, J.; Wang, Q.

    2006-01-01

    The natural isotopic compositions and C/N elemental ratios of sedimentary organic matter were determined in the intertidal flat of the Yangtze Estuary. The results showed that the ratios of carbon and nitrogen stable isotopes were respectively -29.8 per mille to - 26.0 per mille and 1.6 per mille -5.5 per mille in the flood season (July), while they were -27.3 per mille to - 25.6 per mille and 1.7 per mille -7.8 per mille in the dry season (February), respectively. The δ 13 C signatures were remarkably higher in July than in February, and gradually increased from the freshwater areas to the brackish areas. In contrast, there were relatively complex seasonal and spatial changes in stable nitrogen isotopes. It was also reflected that δ 15 N and C/N compositions had been obviously modified by organic matter diagenesis and biological processing, and could not be used to trace the sources of organic matter at the study area. In addition, it was considered that the mixing inputs of terrigenous and marine materials generally dominated sedimentary organic matter in the intertidal flat. The contribution of terrigenous inputs to sedimentary organic matter was roughly estimated according to the mixing balance model of stable carbon isotopes

  7. New developments in the use of stable activable tracers in environmental science

    International Nuclear Information System (INIS)

    Loveland, W.; Keasler, K.; Ghannam, L.; Borovik, A.

    1980-01-01

    Recent developments in the use of stable activable tracers (SATs) in environmental science are reported. (A stable activable tracer is a stable material injected into a system under study and whose concentration is measured by post-sampling activation analysis.) The activable nuclear parts of the tracers studied have been rare earth nuclides with short-lived activation products or Cu. To trace the fate of fluid-bound pollutants (and/or water masses) in marine waters, we have used anionic DTPA complexes of the rare earths. These tracers were shown to be stable (80 to 90% nondissociated) in extensive laboratory tests involving solutions of the tracer in estuarine water including large amounts of marine sediments. Results of a field study in which the flushing time and other hydrological characteristics of an estuarine marina were measured by simultaneously using a fluorescent dye and a SAT are presented. To trace the path of potentially toxic organic molecules, three stable activable tracers, dysprosium(III)-trisacetylacetonate DY(acac) 3 3H 2 O), dysprosium(III)-trisdibenzoylmethane (DY(dbm) 3 H 2 O and copper oxinate Cu (C 9 H 6 ON) 2 were synthesized. Their octanol/water partition coefficients and their solubility in water were measured and used to correlate the tracer species and its biological activity with that of known toxic materials. In a project to demonstrate the simple use of SATs to trace the origin of common insecticides and herbicides, seven common insecticides and herbicides were marked with anionic rare earth DTPA complexes and shown to be detectable at dilutions of 1 part in 10 12 . Two arsenical herbicides were chosen for further study and the tracer/herbicide ratio was shown to remain constant in samples of herbicide material collected on plant surfaces and runoff waters in the environment for long periods

  8. Metrology for stable isotope reference materials: 13C/12C and 18O/16O isotope ratio value assignment of pure carbon dioxide gas samples on the Vienna PeeDee Belemnite-CO2 scale using dual-inlet mass spectrometry.

    Science.gov (United States)

    Srivastava, Abneesh; Michael Verkouteren, R

    2018-05-25

    Isotope ratio measurements have been conducted on a series of isotopically distinct pure CO 2 gas samples using the technique of dual-inlet isotope ratio mass spectrometry (DI-IRMS). The influence of instrumental parameters, data normalization schemes on the metrological traceability and uncertainty of the sample isotope composition have been characterized. Traceability to the Vienna PeeDee Belemnite(VPDB)-CO 2 scale was realized using the pure CO 2 isotope reference materials(IRMs) 8562, 8563, and 8564. The uncertainty analyses include contributions associated with the values of iRMs and the repeatability and reproducibility of our measurements. Our DI-IRMS measurement system is demonstrated to have high long-term stability, approaching a precision of 0.001 parts-per-thousand for the 45/44 and 46/44 ion signal ratios. The single- and two-point normalization bias for the iRMs were found to be within their published standard uncertainty values. The values of 13 C/ 12 C and 18 O/ 16 O isotope ratios are expressed relative to VPDB-CO 2 using the [Formula: see text] and [Formula: see text] notation, respectively, in parts-per-thousand (‰ or per mil). For the samples, value assignments between (-25 to +2) ‰ and (-33 to -1) ‰ with nominal combined standard uncertainties of (0.05, 0.3) ‰ for [Formula: see text] and [Formula: see text], respectively were obtained. These samples are used as laboratory reference to provide anchor points for value assignment of isotope ratios (with VPDB traceability) to pure CO 2 samples. Additionally, they serve as potential parent isotopic source material required for the development of gravimetric based iRMs of CO 2 in CO 2 -free dry air in high pressure gas cylinder packages at desired abundance levels and isotopic composition values. Graphical abstract CO 2 gas isotope ratio metrology.

  9. Split degenerate states and stable p+ip phases from holography

    Energy Technology Data Exchange (ETDEWEB)

    Nie, Zhang-Yu; Zeng, Hui [Kunming University of Science and Technology, Kunming (China); Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing (China); Pan, Qiyuan [Hunan Normal Univ., Key Lab. of Low Dimensional Quantum Structures and Quantum Control of Ministry of Education, and Synergetic Innovation Center for Quantum Effects and Applications, Dept. of Physics, Changsha (China); Zeng, Hua-Bi [Yangzhou University, College of Physics Science and Technology, Yangzhou, Jiangsu (China); National Central University, Department of Physics, Chungli (China)

    2017-02-15

    In this paper, we investigate the p+ip superfluid phases in the complex vector field holographic p-wave model. We find that in the probe limit, the p+ip phase and the p-wave phase are equally stable, hence the p and ip orders can be mixed with an arbitrary ratio to form more general p+λip phases, which are also equally stable with the p-wave and p+ip phases. As a result, the system possesses a degenerate thermal state in the superfluid region. We further study the case on considering the back-reaction on the metric, and we find that the degenerate ground states will be separated into p-wave and p+ip phases, and the p-wave phase is more stable. Finally, due to the different critical temperature of the zeroth order phase transitions from p-wave and p+ip phases to the normal phase, there is a temperature region where the p+ip phase exists but the p-wave phase does not. In this region we find the stable holographic p+ip phase for the first time. (orig.)

  10. Stable-isotope paleoclimatology

    International Nuclear Information System (INIS)

    Deuser, W.G.

    1978-01-01

    Seasonal variations of temperature and salinity in the surface waters of large parts of the oceans are well established. Available data on seasonal distributions of planktonic foraminifera show that the abundances of different species groups peak at different times of the year with an apparent succession of abundance peaks through most of the year. This evidence suggests that a measure of seasonal contrast is recorded in the isotope ratios of oxygen, and perhaps carbon, in the tests of different foraminiferal species. The evaluation of this potential paleoclimatologic tool awaits planned experiments with recent foraminifera in well-known settings, but a variety of available data is consistent with the idea that interspecies differences in 18 O content contain a seasonal component.(auth.)

  11. Detecting isotopic ratio outliers

    International Nuclear Information System (INIS)

    Bayne, C.K.; Smith, D.H.

    1985-01-01

    An alternative method is proposed for improving isotopic ratio estimates. This method mathematically models pulse-count data and uses iterative reweighted Poisson regression to estimate model parameters to calculate the isotopic ratios. This computer-oriented approach provides theoretically better methods than conventional techniques to establish error limits and to identify outliers. 6 refs., 3 figs., 3 tabs

  12. Detecting isotopic ratio outliers

    Science.gov (United States)

    Bayne, C. K.; Smith, D. H.

    An alternative method is proposed for improving isotopic ratio estimates. This method mathematically models pulse-count data and uses iterative reweighted Poisson regression to estimate model parameters to calculate the isotopic ratios. This computer-oriented approach provides theoretically better methods than conventional techniques to establish error limits and to identify outliers.

  13. Detecting isotopic ratio outliers

    International Nuclear Information System (INIS)

    Bayne, C.K.; Smith, D.H.

    1986-01-01

    An alternative method is proposed for improving isotopic ratio estimates. This method mathematically models pulse-count data and uses iterative reweighted Poisson regression to estimate model parameters to calculate the isotopic ratios. This computer-oriented approach provides theoretically better methods than conventional techniques to establish error limits and to identify outliers

  14. GC-MS DETERMINATION OF RATIOS OF STABLE-ISOTOPE LABELED TO NATURAL UREA USING [(CN2)-C-13-N-15]UREA FOR STUDYING UREA KINETICS IN SERUM AND AS A MEANS TO VALIDATE ROUTINE METHODS FOR THE QUANTITATIVE ASSAY OF UREA IN DIALYSATE

    NARCIS (Netherlands)

    WOLTHERS, BG; TEPPER, T; WITHAG, A; NAGEL, GT; DEHAAN, THY; VANLEEUWEN, JJ; STEGEMAN, CA; HUISMAN, RM

    A GC-MS determination of urea in serum or spent dialysate is described, using (CN2)-C-13-N-15-labelled urea and assaying the area ratio of labelled to natural urea by mass fragmentographic monitoring of fragments m/e 153 and 156, after its eventual conversion into the trimethylsilylether-derivative

  15. Managing Complexity

    Energy Technology Data Exchange (ETDEWEB)

    Chassin, David P.; Posse, Christian; Malard, Joel M.

    2004-08-01

    Physical analogs have shown considerable promise for understanding the behavior of complex adaptive systems, including macroeconomics, biological systems, social networks, and electric power markets. Many of today’s most challenging technical and policy questions can be reduced to a distributed economic control problem. Indeed, economically-based control of large-scale systems is founded on the conjecture that the price-based regulation (e.g., auctions, markets) results in an optimal allocation of resources and emergent optimal system control. This paper explores the state of the art in the use physical analogs for understanding the behavior of some econophysical systems and to deriving stable and robust control strategies for them. In particular we review and discussion applications of some analytic methods based on the thermodynamic metaphor according to which the interplay between system entropy and conservation laws gives rise to intuitive and governing global properties of complex systems that cannot be otherwise understood.

  16. One-dimensional stable distributions

    CERN Document Server

    Zolotarev, V M

    1986-01-01

    This is the first book specifically devoted to a systematic exposition of the essential facts known about the properties of stable distributions. In addition to its main focus on the analytic properties of stable laws, the book also includes examples of the occurrence of stable distributions in applied problems and a chapter on the problem of statistical estimation of the parameters determining stable laws. A valuable feature of the book is the author's use of several formally different ways of expressing characteristic functions corresponding to these laws.

  17. Application of Performance Ratios in Portfolio Optimization

    Directory of Open Access Journals (Sweden)

    Aleš Kresta

    2015-01-01

    Full Text Available The cornerstone of modern portfolio theory was established by pioneer work of Harry Markowitz. Based on his mean-variance framework, Sharpe formulated his well-known Sharpe ratio aiming to measure the performance of mutual funds. The contemporary development in computer’s computational power allowed to apply more complex performance ratios, which take into account also higher moments of return probability distribution. Although these ratios were proposed to help the investors to improve the results of portfolio optimization, we empirically demonstrated in our paper that this may not necessarily be true. On the historical dataset of DJIA components we empirically showed that both Sharpe ratio and MAD ratio outperformed Rachev ratio. However, for Rachev ratio we assumed only one level of parameters value. Different set-ups of parameters may provide different results and thus further analysis is certainly required.

  18. Hydrolytically stable titanium-45

    DEFF Research Database (Denmark)

    Severin, Gregory; Fonslet, Jesper; Zhuravlev, Fedor

    2014-01-01

    metal-based chemotherapeutics such as cisplatin. The aim of our work has been to produce the radioactive analogue of one of these Ti(IV)-salan compounds, Ti-salan-dipic [2], which has hydro-lytic stability on the order of weeks. Not only will this allow us to shed some light on the still un...... the physical characteristics are extremely desirable: 45Ti has a 3 hour half-life, a positron branching ratio of 85 %, a low Eβmax of 1.04 MeV, and negligible secondary gamma emission. In terms of isotope production, 45Ti is transmuted from naturally mono-isotopic 45Sc by low energy proton irradiation...... to a water-cooled silver plate. The activated foil was dissolved in 4M HCl, dried under argon at 120 oC, and taken back up in 12M HCl. Here, four (i-iv below) different approaches to removing the Ti from the Sc and labeling were taken with varying success. Briefly: i. 45Ti was separated on hydroxamate resin...

  19. Reproducibility of isotope ratio measurements

    International Nuclear Information System (INIS)

    Elmore, D.

    1981-01-01

    The use of an accelerator as part of a mass spectrometer has improved the sensitivity for measuring low levels of long-lived radionuclides by several orders of magnitude. However, the complexity of a large tandem accelerator and beam transport system has made it difficult to match the precision of low energy mass spectrometry. Although uncertainties for accelerator measured isotope ratios as low as 1% have been obtained under favorable conditions, most errors quoted in the literature for natural samples are in the 5 to 20% range. These errors are dominated by statistics and generally the reproducibility is unknown since the samples are only measured once

  20. Complexity of nearshore strontium-to-calcium ratio variability in a core sample of the massive coral Siderastrea siderea obtained in Coral Bay, St. John, U.S. Virgin Islands

    Science.gov (United States)

    Reich, Christopher D.; Kuffner, Ilsa B.; Hickey, T. Don; Morrison, Jennifer M.; Flannery, Jennifer A.

    2013-01-01

    Strontium-to-calcium ratios (Sr/Ca) were measured on the skeletal matrix of a core sample from a colony of the massive coral Siderastrea siderea collected in Coral Bay, St. John, U.S. Virgin Islands. Strontium and calcium are incorporated into the coral skeleton during the precipitation of aragonite by the coral polyps and their ratio is highly temperature dependent. The robustness of this temperature dependence makes Sr/Ca a reliable proxy for sea surface temperature (SST). Details presented from the St. John S. siderea core indicate that terrestrial inputs of sediment and freshwater can disrupt the chemical balance and subsequently complicate the utility of Sr/Ca in reconstructing historical SST. An approximately 44-year-long record of Sr/Ca shows that an annual SST signal is recorded but with an increasing Sr/Ca trend from 1980 to present, which is likely the result of runoff from the mountainous terrain of St. John. The overwhelming influence of the terrestrial fingerprint on local seawater chemistry makes utilizing Sr/Ca as a SST proxy in nearshore environments very difficult.

  1. Difference and ratio plots

    DEFF Research Database (Denmark)

    Svendsen, Anders Jørgen; Holmskov, U; Bro, Peter

    1995-01-01

    and systemic lupus erythematosus from another previously published study (Macanovic, M. and Lachmann, P.J. (1979) Clin. Exp. Immunol. 38, 274) are also represented using ratio plots. Our observations indicate that analysis by regression analysis may often be misleading....... hitherto unnoted differences between controls and patients with either rheumatoid arthritis or systemic lupus erythematosus. For this we use simple, but unconventional, graphic representations of the data, based on difference plots and ratio plots. Differences between patients with Burkitt's lymphoma...

  2. Stable isotope research pool inventory

    International Nuclear Information System (INIS)

    1980-12-01

    This report contains a listing of electromagnetically separated stable isotopes which are available for distribution within the United States for non-destructive research use from the Oak Ridge National Laboratory on a loan basis. This inventory includes all samples of stable isotopes in the Materials Research Collection and does not designate whether a sample is out on loan or in reprocessing

  3. IsoBank – Stable isotope ecology in the age of ‘Big Data’

    Science.gov (United States)

    Stable isotopes ratios provide valuable information to fish biologists working in a diverse range of fields: e.g. ecologists, population biologists and fishery managers. Ecologists take advantage of stable isotope ratios to provide information on the diet and migration history of consumers or when a...

  4. Inclusion Complex of Zerumbone with Hydroxypropyl-β-Cyclodextrin Induces Apoptosis in Liver Hepatocellular HepG2 Cells via Caspase 8/BID Cleavage Switch and Modulating Bcl2/Bax Ratio

    Directory of Open Access Journals (Sweden)

    Nabilah Muhammad Nadzri

    2013-01-01

    Full Text Available Zerumbone (ZER isolated from Zingiber zerumbet was previously encapsulated with hydroxypropyl-β-cyclodextrin (HPβCD to enhance ZER’s solubility in water, thus making it highly tolerable in the human body. The anticancer effects of this new ZER-HPβCD inclusion complex via apoptosis cell death were assessed in this study for the first time in liver hepatocellular cells, HepG2. Apoptosis was ascertained by morphological study, nuclear stain, and sub-G1 cell population accumulation with G2/M arrest. Further investigations showed the release of cytochrome c and loss of mitochondrial membrane potential, proving mitochondrial dysfunction upon the ZER-HPβCD treatment as well as modulating proapoptotic and anti-apototic Bcl-2 family members. A significant increase in caspase 3/7, caspase 9, and caspase 8 was detected with the depletion of BID cleaved by caspase 8. Collectively, these results prove that a highly soluble inclusion complex of ZER-HPβCD could be a promising anticancer agent for the treatment of hepatocellular carcinoma in humans.

  5. Stable isotope geochemistry : definitions, terminology, measurement and some applications

    International Nuclear Information System (INIS)

    Faure, K.

    2005-01-01

    In 1936, Alfred Nier produced the first precise measurement of isotope abundance ratios and his design still remains the basis of stable isotope mass spectrometry. With this gift from the physicists for routine measurement of isotope ratios, earth scientists began to explore the natural variations of isotopes. Thus began a new era in geoscience research with the hydrological cycle and marine palaeoclimatic research being the first topics to be investigated. Stable isotope measurements have been applied to many fundamental problems in geochemistry, petrology and paleoclimatology, as well as related fields in archaeology, anthropology, physical chemistry, biology and forensic sciences. (author). 52 refs., 11 figs., 2 tabs

  6. Stable-carbon isotope variability in tree foliage and wood

    International Nuclear Information System (INIS)

    Leavitt, S.W.; Long, A.

    1986-01-01

    This study documents variation of stable-carbon isotope ratios ( 13 C/ 12 C) in trees of genera Juniperus and Pinus under field conditions. Results are from cellulose analysis on leaves, twigs, and wood from a number of localities in the southwestern US. Substantial variability, typically 1-3%, exists among leaves, within wood (radially, vertically, circumferentially), and between individuals at a site. These results may help guide sampling in tracer-type studies with stable-carbon isotope ratios and aid in the interpretation of isotopic results from such studies

  7. Reinterpreting the best biomarker of oxidative stress: The 8-iso-prostaglandin F2α/prostaglandin F2α ratio shows complex origins of lipid peroxidation biomarkers in animal models.

    Science.gov (United States)

    Van't Erve, Thomas J; Lih, Fred B; Jelsema, Casey; Deterding, Leesa J; Eling, Thomas E; Mason, Ronald P; Kadiiska, Maria B

    2016-06-01

    Oxidative stress is elevated in numerous environmental exposures and diseases. Millions of dollars have been spent to try to ameliorate this damaging process using anti-oxidant therapies. Currently, the best accepted biomarker of oxidative stress is the lipid oxidation product 8-iso-prostaglandin F2α (8-iso-PGF2α), which has been measured in over a thousand human and animal studies. 8-iso-PGF2α generation has been exclusively attributed to nonenzymatic chemical lipid peroxidation (CLP). However, 8-iso-PGF2α can also be produced enzymatically by prostaglandin-endoperoxide synthases (PGHS) in vivo. When failing to account for PGHS-dependent generation, 8-iso-PGF2α cannot be interpreted as a selective biomarker of oxidative stress. We investigated the formation of 8-iso-PGF2α in rats exposed to carbon tetrachloride (CCl4) or lipopolysaccharide (LPS) using the 8-iso-PGF2α/PGF2α ratio to quantitatively determine the source(s) of 8-iso-PGF2α. Upon exposure to a 120mg/kg dose of CCl4, the contribution of CLP accounted for only 55.6±19.4% of measured 8-iso-PGF2α, whereas in the 1200mg/kg dose, CLP was the predominant source of 8-iso-PGF2α (86.6±8.0% of total). In contrast to CCl4, exposure to 0.5mg/kg LPS was characterized by a significant increase in both the contribution of PGHS (59.5±7.0) and CLP (40.5±14.0%). In conclusion, significant generation of 8-iso-PGF2α occurs through enzymatic as well as chemical lipid peroxidation. The distribution of the contribution is dependent on the exposure agent as well as the dose. The 8-iso-PGF2α/PGF2α ratio accurately determines the source of 8-iso-PGF2α and provides an absolute measure of oxidative stress in vivo. Copyright © 2016. Published by Elsevier Inc.

  8. Stable configurations in social networks

    Science.gov (United States)

    Bronski, Jared C.; DeVille, Lee; Ferguson, Timothy; Livesay, Michael

    2018-06-01

    We present and analyze a model of opinion formation on an arbitrary network whose dynamics comes from a global energy function. We study the global and local minimizers of this energy, which we call stable opinion configurations, and describe the global minimizers under certain assumptions on the friendship graph. We show a surprising result that the number of stable configurations is not necessarily monotone in the strength of connection in the social network, i.e. the model sometimes supports more stable configurations when the interpersonal connections are made stronger.

  9. Development of Stable Isotope Technology

    International Nuclear Information System (INIS)

    Jeong, Do Young; Kim, Cheol Jung; Han, Jae Min

    2009-03-01

    KAERI has obtained an advanced technology with singular originality for laser stable isotope separation. Objectives for this project are to get production technology of Tl-203 stable isotope used for medical application and are to establish the foundation of the pilot system, while we are taking aim at 'Laser Isotope Separation Technology to make resistance to the nuclear proliferation'. And we will contribute to ensuring a nuclear transparency in the world society by taking part in a practical group of NSG and being collaboration with various international groups related to stable isotope separation technology

  10. On the classification of complex vector bundles of stable rank

    Indian Academy of Sciences (India)

    Chern class; K-theory; Atiyah–Singer index theorem; Atiyah–Hirzebruch spectral sequence ... manifolds of arbitrary dimensions, including the rational homogeneous manifolds. We list ..... for particular choices of the base space X. The simple ...

  11. Stable chains and vortex equations on complex vector bundles

    International Nuclear Information System (INIS)

    Xi Zhang

    2004-07-01

    In this paper, we study an object on almost Hermitian manifold M consisting of a finite number of J i -holomorphic vector bundles E i over M and homomorphisms φ i :E 1 →E i-1 . We call such an object a J-holomorphic chain. We then prove a Hitchin-Kobayashi correspondence relating the existence of solutions to certain chain vortex equations and an appropriate notion of stability for the corresponding chains. (author)

  12. Identification and characterization of stable membrane protein complexes

    NARCIS (Netherlands)

    Spelbrink, R.E.J.

    2007-01-01

    Many membrane proteins exist as oligomers. Such oligomers play an important role in a broad variety of cellular processes such as ion transport, energy transduction, osmosensing and cell wall synthesis. We developed an electrophoresis-based method of identifying oligomeric membrane proteins that are

  13. Polymeric nanocapsules ultra stable in complex biological media

    Czech Academy of Sciences Publication Activity Database

    Rodriguez-Emmenegger, Cesar Adolfo; Jäger, Alessandro; Jäger, Eliezer; Štěpánek, Petr; Bologna Alles, A.; Guterres, S. S.; Pohlmann, A. R.; Brynda, Eduard

    2011-01-01

    Roč. 83, č. 2 (2011), s. 376-381 ISSN 0927-7765 R&D Projects: GA AV ČR KAN200670701; GA ČR GAP208/10/1600 Institutional research plan: CEZ:AV0Z40500505 Keywords : core/shell nanocapsules * biodegradable * antifouling coating Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.456, year: 2011

  14. Stable isotope measurements of atmospheric CO2

    International Nuclear Information System (INIS)

    White, J.W.C.; Ferretti, D.F.; Vaughn, B.H.; Francey, R.J.; Allison, C.E.

    2002-01-01

    The measurement of stable carbon isotope ratios of atmospheric carbon dioxide, δ 13 CO 2 are useful for partitioning surface-atmospheric fluxes into terrestrial and oceanic components. δC 18 OO also has potential for segregating photosynthetic and respiratory fluxes in terrestrial ecosystems. Here we describe in detail the techniques for making these measurements. The primary challenge for all of the techniques used to measure isotopes of atmospheric CO 2 is to achieve acceptable accuracy and precision and to maintain them over the decades needed to observe carbon cycle variability. The keys to success such an approach are diligent intercalibrations of laboratories from around the world, as well as the use of multiple techniques such as dual inlet and GC-IRMS and the intercomparison of such measurements. We focus here on two laboratories, the Stable Isotope Lab at the Institute for Arctic and Alpine Research (INSTAAR) at the University of Colorado is described and the Commonwealth Scientific and Industrial Research Organisation - Atmospheric Research (CSIRO). Different approaches exist at other laboratories (e.g. programs operated by Scripps Institution of Oceanography (SIO) and The Center for Atmospheric and Oceanic Studies, Toboku University (TU)) however these are not discussed here. Finally, we also discuss the recently developed Gas Chromatography - Isotope Ratio Mass Spectrometry (GC-IRMS) technique which holds significant promise for measuring ultra-small samples of gas with good precision. (author)

  15. The rectilinear Steiner ratio

    Directory of Open Access Journals (Sweden)

    PO de Wet

    2005-06-01

    Full Text Available The rectilinear Steiner ratio was shown to be 3/2 by Hwang [Hwang FK, 1976, On Steiner minimal trees with rectilinear distance, SIAM Journal on Applied Mathematics, 30, pp. 104– 114.]. We use continuity and introduce restricted point sets to obtain an alternative, short and self-contained proof of this result.

  16. Stable isotope research pool inventory

    International Nuclear Information System (INIS)

    1984-03-01

    This report contains a listing of electromagnetically separated stable isotopes which are available at the Oak Ridge National Laboratory for distribution for nondestructive research use on a loan basis. This inventory includes all samples of stable isotopes in the Research Materials Collection and does not designate whether a sample is out on loan or is in reprocessing. For some of the high abundance naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56

  17. French days on stable isotopes

    International Nuclear Information System (INIS)

    2000-01-01

    These first French days on stable isotopes took place in parallel with the 1. French days of environmental chemistry. Both conferences had common plenary sessions. The conference covers all aspects of the use of stable isotopes in the following domains: medicine, biology, environment, tracer techniques, agronomy, food industry, geology, petroleum geochemistry, cosmo-geochemistry, archaeology, bio-geochemistry, hydrology, climatology, nuclear and particle physics, astrophysics, isotope separations etc.. Abstracts available on CD-Rom only. (J.S.)

  18. Stable isotope research pool inventory

    International Nuclear Information System (INIS)

    1982-01-01

    This report contains a listing of electromagnetically separated stable isotopes which are available for distribution within the United States for nondestructive research use from the Oak Ridge National Laboratory on a loan basis. This inventory includes all samples of stable isotopes in the Material Research Collection and does not designate whether a sample is out on loan or in reprocessing. For some of the high abundance naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56

  19. Pharmaceuticals labelled with stable isotopes

    International Nuclear Information System (INIS)

    Krumbiegel, P.

    1986-11-01

    The relatively new field of pharmaceuticals labelled with stable isotopes is reviewed. Scientific, juridical, and ethical questions are discussed concerning the application of these pharmaceuticals in human medicine. 13 C, 15 N, and 2 H are the stable isotopes mainly utilized in metabolic function tests. Methodical contributions are given to the application of 2 H, 13 C, and 15 N pharmaceuticals showing new aspects and different states of development in the field under discussion. (author)

  20. Transformer ratio enhancement experiment

    International Nuclear Information System (INIS)

    Gai, W.; Power, J. G.; Kanareykin, A.; Neasheva, E.; Altmark, A.

    2004-01-01

    Recently, a multibunch scheme for efficient acceleration based on dielectric wakefield accelerator technology was outlined in J.G. Power, W. Gai, A. Kanareykin, X. Sun. PAC 2001 Proceedings, pp. 114-116, 2002. In this paper we present an experimental program for the design, development and demonstration of an Enhanced Transformer Ratio Dielectric Wakefield Accelerator (ETR-DWA). The principal goal is to increase the transformer ratio R, the parameter that characterizes the energy transfer efficiency from the accelerating structure to the accelerated electron beam. We present here an experimental design of a 13.625 GHz dielectric loaded accelerating structure, a laser multisplitter producing a ramped bunch train, and simulations of the bunch train parameters required. Experimental results of the accelerating structure bench testing and ramped pulsed train generation with the laser multisplitter are shown as well. Using beam dynamic simulations, we also obtain the focusing FODO lattice parameters

  1. Intake to Production Ratio

    DEFF Research Database (Denmark)

    Nazaroff, William; Weschler, Charles J.; Little, John C.

    2012-01-01

    BACKGROUND: Limited data are available to assess human exposure to thousands of chemicals currently in commerce. Information that relates human intake of a chemical to its production and use can help inform understanding of mechanisms and pathways that control exposure and support efforts...... to protect public health.OBJECTIVES: We introduce the intake-to-production ratio (IPR) as an economy-wide quantitative indicator of the extent to which chemical production results in human exposure.METHODS: The IPR was evaluated as the ratio of two terms: aggregate rate of chemical uptake in a human......(n-butyl) phthalate, 1,040 ppm for para-dichlorobenzene, 6,800 ppm for di(isobutyl) phthalate, 7,700 ppm for diethyl phthalate, and 8,000-24,000 ppm (range) for triclosan.CONCLUSION: The IPR is well suited as an aggregate metric of exposure intensity for characterizing population-level exposure to synthesized...

  2. Stable isotopic variation in tropical forest plants for applications in primatology.

    Science.gov (United States)

    Blumenthal, Scott A; Rothman, Jessica M; Chritz, Kendra L; Cerling, Thure E

    2016-10-01

    Stable isotope analysis is a promising tool for investigating primate ecology although nuanced ecological applications remain challenging, in part due to the complex nature of isotopic variability in plant-animal systems. The aim of this study is to investigate sources of carbon and nitrogen isotopic variation at the base of primate food webs that reflect aspects of primate ecology. The majority of primates inhabit tropical forest ecosystems, which are dominated by C3 vegetation. We used stable isotope ratios in plants from Kibale National Park, Uganda, a well-studied closed-canopy tropical forest, to investigate sources of isotopic variation among C3 plants related to canopy stratification, leaf age, and plant part. Unpredictably, our results demonstrate that vertical stratification within the canopy does not explain carbon or nitrogen isotopic variation in leaves. Leaf age can be a significant source of isotopic variation, although the direction and magnitude of this difference is not consistent across tree species. Some plant parts are clearly differentiated in carbon and nitrogen isotopic composition, particularly leaves compared to non-photosynthetic parts such as reproductive parts and woody stem parts. Overall, variation in the isotopic composition of floral communities, plant species, and plant parts demonstrates that stable isotope studies must include analysis of local plant species and parts consumed by the primates under study from within the study area. Am. J. Primatol. 78:1041-1054, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  3. Stable isotope geochemistry : definitions, terminology, measurement and some applications

    International Nuclear Information System (INIS)

    Faure, K.

    2009-01-01

    In 1936, Alfred Nier produced the first precise measurement of isotope abundance ratios and his design still remains the basis of stable isotope mass spectrometry. With this gift from the physicists for routine measurement of isotope ratios, earth scientists began to explore the natural variations of isotopes. Thus began a new era in geoscience research with the hydrological cycle and marine palaeolimatic research being the first topics to be investigated. Stable isotope measurements have been applied to many fundamental problems in geochemistry, petrology, and paleoclimatology, as well as related fields in archaeology, anthropology, physical chemistry, biology and forensic sciences. These applications can be broadly classified into four main types: 1. Thermometry: Formation temperatures of rock and mineral systems are determined on the basis of temperature-dependent fractionations of the isotopic ratios between two or more cogenetic phases. 2. Tracers: Reservoirs like the ocean, the mantle, meteroic waters and organic matter have distinct stable isotope signatures that can be used to trace the origin of rocks, fluids, contaminants etc. 3. Reaction mechanism: Distinctions can be made between diffusion and recrystallization, open and closed systems and bacterial and thermogenic processes. 4. Chemostratigraphy: Abrupt changes (excursions) in the stable isotope ratios of ocean sediments and certain terrestrial materials can be used as stratigraphic markers. (author). 56 refs., 11 figs., 2 tabs.

  4. Stable isotope geochemistry : definitions, terminology, measurement and some applications

    International Nuclear Information System (INIS)

    Faure, K.

    2014-01-01

    In 1936, Alfred Nier produced the first precise measurement of isotope abundance ratios and his design still remains the basis of stable isotope mass spectrometry. With this gift from the physicists for routine measurement of isotope ratios, earth scientists began to explore the natural variations of isotopes. Thus began a new era in geoscience research with the hydrological cycle and marine palaeoclimatic research being the first topics to be investigated. Stable isotope measurements have been applied to many fundamental problems in geochemistry, petrology, and paleoclimatology, as well as related fields in archaeology, anthropology, physical chemistry, biology and forensic sciences. These applications can be broadly classified into four main types: 1. Thermometry: Formation temperatures of rock and mineral systems are determined on the basis of temperature-dependent fractionations of the isotopic ratios between two or more cogenetic phases. 2. Tracers: Reservoirs like the ocean, the mantle, meteoric waters and organic matter have distinct stable isotope signatures that can be used to trace the origin of rocks, fluids, contaminants etc. 3. Reaction mechanism: Distinctions can be made between diffusion and recrystallization, open and closed systems and bacterial and thermogenic processes. 4. Chemostratigraphy: Abrupt changes (excursions) in the stable isotope ratios of ocean sediments and certain terrestrial materials can be used as stratigraphic markers. (author)

  5. Stable isotope geochemistry: definitions, terminology, measurement and some applications

    International Nuclear Information System (INIS)

    Faure, K.

    2015-01-01

    In 1936, Alfred Nier produced the first precise measurement of isotope abundance ratios and his design still remains the basis of stable isotope mass spectrometry. With this gift from the physicists for routine measurement of isotope ratios, earth scientists began to explore the natural variations of isotopes. Thus began a new era in geoscience research with the hydrological cycle and marine palaeoclimatic research being the first topics to be investigated. Stable isotope measurements have been applied to many fundamental problems in geochemistry, petrology, and paleoclimatology, as well as related fields in archaeology, anthropology, physical chemistry, biology and forensic sciences. These applications can be broadly classified into four main types: 1. Thermometry: Formation temperatures of rock and mineral systems are determined on the basis of temperature-dependent fractionations of the isotopic ratios between two or more cogenetic phases. 2. Tracers: Reservoirs like the ocean, the mantle, meteoric waters and organic matter have distinct stable isotope signatures that can be used to trace the origin of rocks, fluids, contaminants etc. 3. Reaction mechanism: Distinctions can be made between diffusion and recrystallization, open and closed systems and bacterial and thermogenic processes. 4. Chemostratigraphy: Abrupt changes (excursions) in the stable isotope ratios of ocean sediments and certain terrestrial materials can be used as stratigraphic markers. (author).

  6. Stable isotope geochemistry : definitions, terminology, measurement and some applications

    International Nuclear Information System (INIS)

    Faure, K.

    2012-01-01

    In 1936, Alfred Nier produced the first precise measurement of isotope abundance ratios and his design still remains the basis of stable isotope mass spectrometry. With this gift from the physicists for routine measurement of isotope ratios, earth scientists began to explore the natural variations of isotopes. Thus began a new era in geoscience research with the hydrological cycle and marine palaeoclimatic research being the first topics to be investigated. Stable isotope measurements have been applied to many fundamental problems in geochemistry, petrology, and paleoclimatology, as well as related fields in archaeology, anthropology, physical chemistry, biology and forensic sciences. These applications can be broadly classified into four main types: 1. Thermometry: Formation temperatures of rock and mineral systems are determined on the basis of temperature-dependent fractionations of the isotopic ratios between two or more cogenetic phases. 2. Tracers: Reservoirs like the ocean, the mantle, meteoric waters and organic matter have distinct stable isotope signatures that can be used to trace the origin of rocks, fluids, contaminants etc. 3. Reaction mechanism: Distinctions can be made between diffusion and recrystallization, open and closed systems and bacterial and thermogenic processes. 4. Chemostratigraphy: Abrupt changes (excursions) in the stable isotope ratios of ocean sediments and certain terrestrial materials can be used as stratigraphic markers. (author). 89 refs., 12 figs., 2 tabs.

  7. Stable isotope geochemistry : definitions, terminology, measurement and some applications

    International Nuclear Information System (INIS)

    Faure, K.

    2008-01-01

    In 1936, Alfred Nier produced the first precise measurement of isotope abundance ratios and his design still remains the basis of stable isotope mass spectrometry. With this gift from the physicists for routine measurement of isotope ratios, earth scientists began to explore the natural variations of isotopes. Thus began a new era in geoscience research with the hydrological cycle and marine palaeolimatic research being the first topics to be investigated. Stable isotope measurements have been applied to many fundamental problems in geochemistry, petrology, and paleoclimatology, as well as related fields in archaeology, anthropology, physical chemistry, biology and forensic sciences. These applications can be broadly classified into four main types: 1. Thermometry: Formation temperatures of rock and mineral systems are determined on the basis of temperature-dependent fractionations of the isotopic ratios between two or more cogenetic phases. 2. Tracers: Reservoirs like the ocean, the mantle, meteroic waters and organic matter have distinct stable isotope signatures that can be used to trace the origin of rocks, fluids, contaminants etc. 3. Reaction mechanism: Distinctions can be made between diffusion and recrystallization, open and closed systems and bacterial and thermogenic processes. 4. Chemostratigraphy: Abrupt changes (excursions) in the stable isotope ratios of ocean sediments and certain terrestrial materials can be used as stratigraphic markers. (author). 56 refs., 11 figs., 2 tabs

  8. Stable isotope geochemistry : definitions, terminology, measurement and some applications

    International Nuclear Information System (INIS)

    Faure, K.

    2009-01-01

    In 1936, Alfred Nier produced the first precise measurement of isotope abundance ratios and his design still remains the basis of stable isotope mass spectrometry. With this gift from the physicists for routine measurement of isotope ratios, earth scientists began to explore the natural variations of isotopes. Thus began a new era in geoscience research with the hydrological cycle and marine palaeolimatic research being the first topics to be investigated. Stable isotope measurements have been applied to many fundamental problems in geochemistry, petrology, and paleoclimatology, as well as related fields in archaeology, anthropology, physical chemistry, biology and forensic sciences. These applications can be broadly classified into four main types: 1. Thermometry: Formation temperatures of rock and mineral systems are determined on the basis of temperature-dependent fractionations of the isotopic ratios between two or more cogenetic phases. 2. Tracers: Reservoirs like the ocean, the mantle, meteroic waters and organic matter have distinct stable isotope signatures that can be used to trace the origin of rocks, fluids, contaminants etc. 3. Reaction mechanism: Distinctions can be made between diffusion and recrystallization, open and closed systems and bacterial and thermogenic processes. 4. Chemostratigraphy: Abrupt changes (excursions) in the stable isotope ratios of ocean sediments and certain terrestrial materials can be used as stratigraphic markers. (author). 56 refs., 11 figs., 2 tabs

  9. Stable isotope geochemistry : definitions, terminology, measurement and some applications

    International Nuclear Information System (INIS)

    Faure, K.

    2016-01-01

    In 1936, Alfred Nier produced the first precise measurement of isotope abundance ratios and his design still remains the basis of stable isotope mass spectrometry. With this gift from the physicists for routine measurement of isotope ratios, earth scientists began to explore the natural variations of isotopes. Thus began a new era in geoscience research with the hydrological cycle and marine palaeoclimatic research being the first topics to be investigated. Stable isotope measurements have been applied to many fundamental problems in geochemistry, petrology, and paleoclimatology, as well as related fields in archaeology, anthropology, physical chemistry, biology and forensic sciences. These applications can be broadly classified into four main types: 1. Thermometry: Formation temperatures of rock and mineral systems are determined on the basis of temperature-dependent fractionations of the isotopic ratios between two or more cogenetic phases. 2. Tracers: Reservoirs like the ocean, the mantle, meteoric waters and organic matter have distinct stable isotope signatures that can be used to trace the origin of rocks, fluids, contaminants etc. 3. Reaction mechanism: Distinctions can be made between diffusion and recrystallization, open and closed systems and bacterial and thermogenic processes. 4. Chemostratigraphy: Abrupt changes (excursions) in the stable isotope ratios of ocean sediments and certain terrestrial materials can be used as stratigraphic markers. (author).

  10. Stable isotope geochemistry : definitions, terminology, measurement and some applications

    International Nuclear Information System (INIS)

    Faure, K.

    2013-01-01

    In 1936, Alfred Nier produced the first precise measurement of isotope abundance ratios and his design still remains the basis of stable isotope mass spectrometry. With this gift from the physicists for routine measurement of isotope ratios, earth scientists began to explore the natural variations of isotopes. Thus began a new era in geoscience research with the hydrological cycle and marine palaeoclimatic research being the first topics to be investigated. Stable isotope measurements have been applied to many fundamental problems in geochemistry, petrology, and paleoclimatology, as well as related fields in archaeology, anthropology, physical chemistry, biology and forensic sciences. These applications can be broadly classified into four main types: 1. Thermometry: Formation temperatures of rock and mineral systems are determined on the basis of temperature-dependent fractionations of the isotopic ratios between two or more cogenetic phases. 2. Tracers: Reservoirs like the ocean, the mantle, meteoric waters and organic matter have distinct stable isotope signatures that can be used to trace the origin of rocks, fluids, contaminants etc. 3. Reaction mechanism: Distinctions can be made between diffusion and recrystallization, open and closed systems and bacterial and thermogenic processes. 4. Chemostratigraphy: Abrupt changes (excursions) in the stable isotope ratios of ocean sediments and certain terrestrial materials can be used as stratigraphic markers. (author). 91 refs., 12 figs., 2 tabs.

  11. Synthesis of several tetraaza macrocyclic amine ligands and the biodistribution of their Tc-complexes

    International Nuclear Information System (INIS)

    Ketring, A.R.

    1982-01-01

    Several macrocyclic tetraaza ligands were synthesized and their /sup 99m/Tc-complexes prepared. The biological distribution of these complexes was examined to determine their possible utility as radiodiagnostic agents. The simplest of the macrocyclic tetraaza ligands studied, cyclam, forms a very stable cationic complex with Tc when pertechnetate is reduced with stannous ion in an aqueous solution of the ligand. When injected intravenously into mice Tc-cyclam was excreted predominantly by the urinary system. Derivatives of cyclam which were synthesized contained aromatic or aliphatic substituents and formed more lipophilic complexes with Tc. The complexes were formed in high yield as determined by paper chromatography, thin layer chromatography, electrophoresis and/or high performance liquid chromatography. Relative lipophilicities were determined for the complexes by octanol-to-water extractions. Animal studies using mice indicated there was an inverse relationship between the octanol-to-water extraction ratio and urinary excretion. Two of the complexes having relatively high octanol-to-water extraction ratios were significantly excreted by the hepatobiliary system with localization in the gall bladder. The complex having the highest octanol-to-water ratio was not excreted significantly by the hepatobiliary system, but cleared very slowly from the blood and localized in the liver, lungs, spleen and to some extent the heart. Derivatization of cyclam can be performed without greatly reducing its ability to complex Tc but greatly influencing the biological distribution of its Tc complex. This indicates that there is a potential for preparing radiodiagnostic agents using macrocyclic tetraaza ligands

  12. Non-traditional Stable Isotope Systematics of Seafloor Hydrothermal Systems

    Science.gov (United States)

    Rouxel, O. J.

    2009-05-01

    Seafloor hydrothermal activity at mid-ocean ridges is one of the fundamental processes controlling the chemistry of the oceans and the altered oceanic crust. Past studies have demonstrated the complexity and diversity of seafloor hydrothermal systems and have highlighted the importance of subsurface environments in controlling the composition of hydrothermal fluids and mineralization types. Traditionally, the behavior of metals in seafloor hydrothermal systems have been investigated by integrating results from laboratory studies, theoretical models, mineralogy and fluid and mineral chemistry. Isotope ratios of various metals and metalloids, such as Fe, Cu, Zn, Se, Cd and Sb have recently provided new approaches for the study of seafloor hydrothermal systems. Despite these initial investigations, the cause of the isotopic variability of these elements remains poorly constrained. We have little understanding of the isotope variations between vent types (black or white smokers) as well as the influence of source rock composition (basalt, felsic or ultrabasic rocks) and alteration types. Here, I will review and present new results of metal isotope systematics of seafloor hydrothermal systems, in particular: (1) determination of empirical isotope fractionation factors for Zn, Fe and Cu-isotopes through isotopic analysis of mono-mineralic sulfide grains lining the internal chimney wall in contact with hydrothermal fluid; (2) comparison of Fe- and Cu-isotope signatures of vent fluids from mid- oceanic and back-arc hydrothermal fields, spanning wide ranges of pH, temperature, metal concentrations and contributions of magmatic fluids enriched in SO2. Ultimately, the use of complementary non-traditional stable isotope systems may help identify and constrain the complex interactions between fluids,minerals, and organisms in seafloor hydrothermal systems.

  13. STABLE ISOTOPE GEOCHEMISTRY OF MASSIVE ICE

    Directory of Open Access Journals (Sweden)

    Yurij K. Vasil’chuk

    2016-01-01

    Full Text Available The paper summarises stable-isotope research on massive ice in the Russian and North American Arctic, and includes the latest understanding of massive-ice formation. A new classification of massive-ice complexes is proposed, encompassing the range and variabilityof massive ice. It distinguishes two new categories of massive-ice complexes: homogeneousmassive-ice complexes have a similar structure, properties and genesis throughout, whereasheterogeneous massive-ice complexes vary spatially (in their structure and properties andgenetically within a locality and consist of two or more homogeneous massive-ice bodies.Analysis of pollen and spores in massive ice from Subarctic regions and from ice and snow cover of Arctic ice caps assists with interpretation of the origin of massive ice. Radiocarbon ages of massive ice and host sediments are considered together with isotope values of heavy oxygen and deuterium from massive ice plotted at a uniform scale in order to assist interpretation and correlation of the ice.

  14. The Reference Return Ratio

    DEFF Research Database (Denmark)

    Nicolaisen, Jeppe; Faber Frandsen, Tove

    2008-01-01

    The paper introduces a new journal impact measure called The Reference Return Ratio (3R). Unlike the traditional Journal Impact Factor (JIF), which is based on calculations of publications and citations, the new measure is based on calculations of bibliographic investments (references) and returns...... (citations). A comparative study of the two measures shows a strong relationship between the 3R and the JIF. Yet, the 3R appears to correct for citation habits, citation dynamics, and composition of document types - problems that typically are raised against the JIF. In addition, contrary to traditional...

  15. Potential support ratios

    DEFF Research Database (Denmark)

    Kjærgaard, Søren; Canudas-Romo, Vladimir

    2017-01-01

    The ‘prospective potential support ratio’ has been proposed by researchers as a measure that accurately quantifies the burden of ageing, by identifying the fraction of a population that has passed a certain measure of longevity, for example, 17 years of life expectancy. Nevertheless......, the prospective potential support ratio usually focuses on the current mortality schedule, or period life expectancy. Instead, in this paper we look at the actual mortality experienced by cohorts in a population, using cohort life tables. We analyse differences between the two perspectives using mortality models...

  16. [Current Treatment of Stable Angina].

    Science.gov (United States)

    Toggweiler, Stefan; Jamshidi, Peiman; Cuculi, Florim

    2015-06-17

    Current therapy for stable angina includes surgical and percutaneous revascularization, which has been improved tremendously over the last decades. Smoking cessation and regular exercise are the cornerstone for prevention of further cerebrovascular events. Medical treatment includes treatment of cardiovascular risk factors and antithrombotic management, which can be a challenge in some patients. Owing to the fact the coronary revascularization is readily accessible these days in many industrialized countries, the importance of antianginal therapy has decreased over the past years. This article presents a contemporary overview of the management of patients with stable angina in the year 2015.

  17. Tau hadronic branching ratios

    CERN Document Server

    Buskulic, Damir; De Bonis, I; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Odier, P; Pietrzyk, B; Ariztizabal, F; Chmeissani, M; Crespo, J M; Efthymiopoulos, I; Fernández, E; Fernández-Bosman, M; Gaitan, V; Martínez, M; Orteu, S; Pacheco, A; Padilla, C; Palla, Fabrizio; Pascual, A; Perlas, J A; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Farilla, A; Gelao, G; Girone, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Natali, S; Nuzzo, S; Ranieri, A; Raso, G; Romano, F; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Bonvicini, G; Cattaneo, M; Comas, P; Coyle, P; Drevermann, H; Engelhardt, A; Forty, Roger W; Frank, M; Hagelberg, R; Harvey, J; Jacobsen, R; Janot, P; Jost, B; Kneringer, E; Knobloch, J; Lehraus, Ivan; Markou, C; Martin, E B; Mato, P; Minten, Adolf G; Miquel, R; Oest, T; Palazzi, P; Pater, J R; Pusztaszeri, J F; Ranjard, F; Rensing, P E; Rolandi, Luigi; Schlatter, W D; Schmelling, M; Schneider, O; Tejessy, W; Tomalin, I R; Venturi, A; Wachsmuth, H W; Wiedenmann, W; Wildish, T; Witzeling, W; Wotschack, J; Ajaltouni, Ziad J; Bardadin-Otwinowska, Maria; Barrès, A; Boyer, C; Falvard, A; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rossignol, J M; Saadi, F; Fearnley, Tom; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Kyriakis, A; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Zachariadou, K; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Passalacqua, L; Rougé, A; Rumpf, M; Tanaka, R; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Focardi, E; Parrini, G; Corden, M; Delfino, M C; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Pepé-Altarelli, M; Dorris, S J; Halley, A W; ten Have, I; Knowles, I G; Lynch, J G; Morton, W T; O'Shea, V; Raine, C; Reeves, P; Scarr, J M; Smith, K; Smith, M G; Thompson, A S; Thomson, F; Thorn, S; Turnbull, R M; Becker, U; Braun, O; Geweniger, C; Graefe, G; Hanke, P; Hepp, V; Kluge, E E; Putzer, A; Rensch, B; Schmidt, M; Sommer, J; Stenzel, H; Tittel, K; Werner, S; Wunsch, M; Beuselinck, R; Binnie, David M; Cameron, W; Colling, D J; Dornan, Peter J; Konstantinidis, N P; Moneta, L; Moutoussi, A; Nash, J; San Martin, G; Sedgbeer, J K; Stacey, A M; Dissertori, G; Girtler, P; Kuhn, D; Rudolph, G; Bowdery, C K; Brodbeck, T J; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Sloan, Terence; Whelan, E P; Williams, M I; Galla, A; Greene, A M; Kleinknecht, K; Quast, G; Raab, J; Renk, B; Sander, H G; Wanke, R; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Bencheikh, A M; Benchouk, C; Bonissent, A; Bujosa, G; Calvet, D; Carr, J; Diaconu, C A; Etienne, F; Thulasidas, M; Nicod, D; Payre, P; Rousseau, D; Talby, M; Abt, I; Assmann, R W; Bauer, C; Blum, Walter; Brown, D; Dietl, H; Dydak, Friedrich; Ganis, G; Gotzhein, C; Jakobs, K; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Saint-Denis, R; Wolf, G; Alemany, R; Boucrot, J; Callot, O; Cordier, A; Courault, F; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Jacquet, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Musolino, G; Nikolic, I A; Park, H J; Park, I C; Schune, M H; Simion, S; Veillet, J J; Videau, I; Abbaneo, D; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Rizzo, G; Sanguinetti, G; Sciabà, A; Spagnolo, P; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Triggiani, G; Vannini, C; Verdini, P G; Walsh, J; Betteridge, A P; Blair, G A; Bryant, L M; Cerutti, F; Gao, Y; Green, M G; Johnson, D L; Medcalf, T; Mir, L M; Perrodo, P; Strong, J A; Bertin, V; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Edwards, M; Maley, P; Norton, P R; Thompson, J C; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Marx, B; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Johnson, R P; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Beddall, A; Booth, C N; Boswell, R; Cartwright, S L; Combley, F; Dawson, I; Köksal, A; Letho, M; Newton, W M; Rankin, C; Thompson, L F; Böhrer, A; Brandt, S; Cowan, G D; Feigl, E; Grupen, Claus; Lutters, G; Minguet-Rodríguez, J A; Rivera, F; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Ragusa, F; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Bellantoni, L; Elmer, P; Feng, Z; Ferguson, D P S; Gao, Y S; González, S; Grahl, J; Harton, J L; Hayes, O J; Hu, H; McNamara, P A; Nachtman, J M; Orejudos, W; Pan, Y B; Saadi, Y; Schmitt, M; Scott, I J; Sharma, V; Turk, J; Walsh, A M; Wu Sau Lan; Wu, X; Yamartino, J M; Zheng, M; Zobernig, G

    1996-01-01

    From 64492 selected \\tau-pair events, produced at the Z^0 resonance, the measurement of the tau decays into hadrons from a global analysis using 1991, 1992 and 1993 ALEPH data is presented. Special emphasis is given to the reconstruction of photons and \\pi^0's, and the removal of fake photons. A detailed study of the systematics entering the \\pi^0 reconstruction is also given. A complete and consistent set of tau hadronic branching ratios is presented for 18 exclusive modes. Most measurements are more precise than the present world average. The new level of precision reached allows a stringent test of \\tau-\\mu universality in hadronic decays, g_\\tau/g_\\mu \\ = \\ 1.0013 \\ \\pm \\ 0.0095, and the first measurement of the vector and axial-vector contributions to the non-strange hadronic \\tau decay width: R_{\\tau ,V} \\ = \\ 1.788 \\ \\pm \\ 0.025 and R_{\\tau ,A} \\ = \\ 1.694 \\ \\pm \\ 0.027. The ratio (R_{\\tau ,V} - R_{\\tau ,A}) / (R_{\\tau ,V} + R_{\\tau ,A}), equal to (2.7 \\pm 1.3) \\ \\%, is a measure of the importance of Q...

  18. Isotope ratios as pollutant source and behaviour indicators

    International Nuclear Information System (INIS)

    1975-01-01

    Recent years have witnessed significant advances in isotope techniques for identifying origins and for studying the behaviour of trace contaminants and pollutants of the environment under actual existing environmental conditions. Improvements in the supply of stable isotopes and their labelled compounds, instrumental analysis and information on stable or radioactive isotopic ratios of existing environmental contaminants as a function of origin or behaviour have provided relatively new tools for the environmental scientist. While variations in natural or existing environmental stable and radioactive nuclides could be regarded as 'background noise' in conventional tracer experiments they promised unique information about sources and behaviour to those who listened carefully. (author)

  19. Stable isotope views on ecosystem function: challenging or challenged?

    Science.gov (United States)

    Resco, Víctor; Querejeta, José I; Ogle, Kiona; Voltas, Jordi; Sebastià, Maria-Teresa; Serrano-Ortiz, Penélope; Linares, Juan C; Moreno-Gutiérrez, Cristina; Herrero, Asier; Carreira, José A; Torres-Cañabate, Patricia; Valladares, Fernando

    2010-06-23

    Stable isotopes and their potential for detecting various and complex ecosystem processes are attracting an increasing number of scientists. Progress is challenging, particularly under global change scenarios, but some established views have been challenged. The IX meeting of the Spanish Association of Terrestrial Ecology (AAET, Ubeda, 18-22 October 2009) hosted a symposium on the ecology of stable isotopes where the linear mixing model approach of partitioning sinks and sources of carbon and water fluxes within an ecosystem was challenged, and new applications of stable isotopes for the study of plant interactions were evaluated. Discussion was also centred on the need for networks that monitor ecological processes using stable isotopes and key ideas for fostering future research with isotopes.

  20. Stable isotope views on ecosystem function: challenging or challenged?

    Science.gov (United States)

    Resco, Víctor; Querejeta, José I.; Ogle, Kiona; Voltas, Jordi; Sebastià, Maria-Teresa; Serrano-Ortiz, Penélope; Linares, Juan C.; Moreno-Gutiérrez, Cristina; Herrero, Asier; Carreira, José A.; Torres-Cañabate, Patricia; Valladares, Fernando

    2010-01-01

    Stable isotopes and their potential for detecting various and complex ecosystem processes are attracting an increasing number of scientists. Progress is challenging, particularly under global change scenarios, but some established views have been challenged. The IX meeting of the Spanish Association of Terrestrial Ecology (AAET, Úbeda, 18–22 October 2009) hosted a symposium on the ecology of stable isotopes where the linear mixing model approach of partitioning sinks and sources of carbon and water fluxes within an ecosystem was challenged, and new applications of stable isotopes for the study of plant interactions were evaluated. Discussion was also centred on the need for networks that monitor ecological processes using stable isotopes and key ideas for fostering future research with isotopes. PMID:20015858

  1. Peak power ratio generator

    Science.gov (United States)

    Moyer, R.D.

    A peak power ratio generator is described for measuring, in combination with a conventional power meter, the peak power level of extremely narrow pulses in the gigahertz radio frequency bands. The present invention in a preferred embodiment utilizes a tunnel diode and a back diode combination in a detector circuit as the only high speed elements. The high speed tunnel diode provides a bistable signal and serves as a memory device of the input pulses for the remaining, slower components. A hybrid digital and analog loop maintains the peak power level of a reference channel at a known amount. Thus, by measuring the average power levels of the reference signal and the source signal, the peak power level of the source signal can be determined.

  2. Possibility of stable quark stars

    International Nuclear Information System (INIS)

    Bowers, R.L.; Gleeson, A.M.; Pedigo, R.D.

    1976-08-01

    A recent zero temperature equation of state which contains quark-partons separated from conventional baryons by a phase transition is used to investigate the stability of quark stars. The sensitivity to the input physics is also considered. The conclusions, which are found to be relatively model independent, indicate that a separately identifiable class of stable objects called quark stars does not exist

  3. Radiation-stable polyolefin compositions

    International Nuclear Information System (INIS)

    Rekers, J.W.

    1986-01-01

    This invention relates to compositions of olefinic polymers suitable for high energy radiation treatment. In particular, the invention relates to olefinic polymer compositions that are stable to sterilizing dosages of high energy radiation such as a gamma radiation. Stabilizers are described that include benzhydrol and benzhydrol derivatives; these stabilizers may be used alone or in combination with secondary antioxidants or synergists

  4. Effects of euthanasia method on stable-carbon and stable-nitrogen isotope analysis for an ectothermic vertebrate.

    Science.gov (United States)

    Atwood, Meredith A

    2013-04-30

    Stable isotope analysis is a critical tool for understanding ecological food webs; however, results can be sensitive to sample preparation methods. To limit the possibility of sample contamination, freezing is commonly used to euthanize invertebrates and preserve non-lethal samples from vertebrates. For destructive sampling of vertebrates, more humane euthanasia methods are preferred to freezing and it is essential to evaluate how these euthanasia methods affect stable isotope results. Stable isotope ratios and elemental composition of carbon and nitrogen were used to evaluate whether the euthanasia method compromised the integrity of the sample for analysis. Specifically, the stable isotope and C:N ratios were compared for larval wood frogs (Rana sylvatica  =  Lithobates sylvaticus), an ectothermic vertebrate, that had been euthanized by freezing with four different humane euthanasia methods: CO2, benzocaine, MS-222 (tricaine methanesulfonate), and 70% ethanol. The euthanasia method was not related to the δ(13)C or δ(15)N values and the comparisons revealed no differences between freezing and any of the other treatments. However, there were slight (non-significant) differences in the isotope ratios of benzocaine and CO2 when each was compared with freezing. The elemental composition was altered by the euthanasia method employed. The percentage nitrogen was higher in CO2 treatments than in freezing, and similar (non-significant) trends were seen for ethanol treatments relative to freezing. The resulting C:N ratios were higher for benzocaine treatments than for both CO2 and ethanol. Similar (non-significant) trends suggested that the C:N ratios were also higher for animals euthanized by freezing than for both CO2 and ethanol euthanasia methods. The euthanasia method had a larger effect on elemental composition than stable isotope ratios. The percentage nitrogen and the subsequent C:N ratios were most affected by the CO2 and ethanol euthanasia methods, whereas

  5. Stability of high β large aspect ratio tokamaks

    International Nuclear Information System (INIS)

    Cowley, S.C.

    1991-10-01

    High β(β much-gt ε/q 2 ) large aspect ratio (ε much-gt 1) tokamak equilibria are shown to be always stable to ideal M.H.D. modes that are localized about a flux surface. Both the ballooning and interchange modes are shown to be stable. This work uses the analytic high β large aspect ratio tokamak equilibria developed by Cowley et.al., which are valid for arbitrary pressure and safety factor profiles. The stability results make no assumption about these profiles or the shape of the boundary. 14 refs., 4 figs

  6. From Fibonacci Sequence to the Golden Ratio

    Directory of Open Access Journals (Sweden)

    Alberto Fiorenza

    2013-01-01

    Full Text Available We consider the well-known characterization of the Golden ratio as limit of the ratio of consecutive terms of the Fibonacci sequence, and we give an explanation of this property in the framework of the Difference Equations Theory. We show that the Golden ratio coincides with this limit not because it is the root with maximum modulus and multiplicity of the characteristic polynomial, but, from a more general point of view, because it is the root with maximum modulus and multiplicity of a restricted set of roots, which in this special case coincides with the two roots of the characteristic polynomial. This new perspective is the heart of the characterization of the limit of ratio of consecutive terms of all linear homogeneous recurrences with constant coefficients, without any assumption on the roots of the characteristic polynomial, which may be, in particular, also complex and not real.

  7. Stable Isotope Quantitative N-Glycan Analysis by Liquid Separation Techniques and Mass Spectrometry.

    Science.gov (United States)

    Mittermayr, Stefan; Albrecht, Simone; Váradi, Csaba; Millán-Martín, Silvia; Bones, Jonathan

    2017-01-01

    Liquid phase separation analysis and subsequent quantitation remains a challenging task for protein-derived oligosaccharides due to their inherent structural complexity and diversity. Incomplete resolution or co-detection of multiple glycan species complicates peak area-based quantitation and associated statistical analysis when optical detection methods are used. The approach outlined herein describes the utilization of stable isotope variants of commonly used fluorescent tags that allow for mass-based glycan identification and relative quantitation following separation by liquid chromatography (LC) or capillary electrophoresis (CE). Comparability assessment of glycoprotein-derived oligosaccharides is performed by derivatization with commercially available isotope variants of 2-aminobenzoic acid or aniline and analysis by LC- and CE-mass spectrometry. Quantitative information is attained from the extracted ion chromatogram/electropherogram ratios generated from the light and heavy isotope clusters.

  8. Perceptually stable regions for arbitrary polygons.

    Science.gov (United States)

    Rocha, J

    2003-01-01

    Zou and Yan have recently developed a skeletonization algorithm of digital shapes based on a regularity/singularity analysis; they use the polygon whose vertices are the boundary pixels of the image to compute a constrained Delaunay triangulation (CDT) in order to find local symmetries and stable regions. Their method has produced good results but it is slow since its complexity depends on the number of contour pixels. This paper presents an extension of their technique to handle arbitrary polygons, not only polygons of short edges. Consequently, not only can we achieve results as good as theirs for digital images, but we can also compute skeletons of polygons of any number of edges. Since we can handle polygonal approximations of figures, the skeletons are more resilient to noise and faster to process.

  9. Toward Practical Secure Stable Matching

    Directory of Open Access Journals (Sweden)

    Riazi M. Sadegh

    2017-01-01

    Full Text Available The Stable Matching (SM algorithm has been deployed in many real-world scenarios including the National Residency Matching Program (NRMP and financial applications such as matching of suppliers and consumers in capital markets. Since these applications typically involve highly sensitive information such as the underlying preference lists, their current implementations rely on trusted third parties. This paper introduces the first provably secure and scalable implementation of SM based on Yao’s garbled circuit protocol and Oblivious RAM (ORAM. Our scheme can securely compute a stable match for 8k pairs four orders of magnitude faster than the previously best known method. We achieve this by introducing a compact and efficient sub-linear size circuit. We even further decrease the computation cost by three orders of magnitude by proposing a novel technique to avoid unnecessary iterations in the SM algorithm. We evaluate our implementation for several problem sizes and plan to publish it as open-source.

  10. Stable isotope research pool inventory

    International Nuclear Information System (INIS)

    1986-08-01

    This report contains a listing of electromagnetically separated stable isotopes which are available at the Oak Ridge National Laboratory for distribution for nondestructive research use on a loan basis. This inventory includes all samples of stable isotopes in the Research Materials Collection and does not designate whether a sample is out on loan or is in reprocessing. For some of the high-abundance, naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56. All requests for the loan of samples should be submitted with a summary of the purpose of the loan to: Iotope Distribution Office, Oak Ridge National Laboratory, P.O. Box X, Oak Ridge, Tennessee 37831. Requests from non-DOE contractors and from foreign institutions require DOE approval

  11. Stable isotopes and the environment

    International Nuclear Information System (INIS)

    Krouse, H.R.

    1990-01-01

    Whereas traditionally, stable isotope research has been directed towards resource exploration and development, it is finding more frequent applications in helping to assess the impacts of resource utilization upon ecosystems. Among the many pursuits, two themes are evident: tracing the transport and conversions of pollutants in the environment and better understanding of the interplay among environmental receptors, e.g. food web studies. Stable isotope data are used primarily to identify the presence of pollutants in the environment and with a few exceptions, the consequence of their presence must be assessed by other techniques. Increasing attention has been given to the isotopic composition of humans with many potential applications in areas such as paleodiets, medicine, and criminology. In this brief overview examples are used from the Pacific Rim to illustrate the above concepts. 26 refs., 1 tab., 3 figs

  12. Towards stable acceleration in LINACS

    CERN Document Server

    Dubrovskiy, A D

    2014-01-01

    Ultra-stable and -reproducible high-energy particle beams with short bunches are needed in novel linear accelerators and, in particular, in the Compact Linear Collider CLIC. A passive beam phase stabilization system based on a bunch compression with a negative transfer matrix element R56 and acceleration at a positive off-crest phase is proposed. The motivation and expected advantages of the proposed scheme are outlined.

  13. Stable Structures for Distributed Applications

    OpenAIRE

    Eugen DUMITRASCU; Ion IVAN

    2008-01-01

    For distributed applications, we define the linear, tree and graph structure types with different variants and modalities to aggregate them. The distributed applications have assigned structures that through their characteristics influence the costs of stages for developing cycle and the costs for exploitation, transferred to each user. We also present the quality characteristics of a structure for a stable application, which is focused on stability characteristic. For that characteristic we ...

  14. Energy Profit Ratio Compared

    International Nuclear Information System (INIS)

    Amano, Osamu

    2007-01-01

    We need more oil energy to take out oil under the ground. Limit resources make us consider other candidates of energy source instead of oil. Electricity shall be the main role more and more like electric vehicles and air conditioners so we should consider electricity generation ways. When we consider what kind of electric power generation is the best or suitable, we should not only power generation plant but whole process from mining to power generation. It is good way to use EPR, Energy Profit Ratio, to analysis which type is more efficient and which part is to do research and development when you see the input breakdown analysis. Electricity by the light water nuclear power plant, the hydrogen power plant and the geothermal power plant are better candidates from EPR analysis. Forecasting the world primly energy supply in 2050, it is said that the demand will be double of the demand in 2000 and the supply will not be able to satisfy the demand in 2050. We should save 30% of the demand and increase nuclear power plants 3.5 times more and recyclable energy like hydropower plants 3 times more. When the nuclear power plants are 3.5 times more then uranium peak will come and we will need breed uranium. I will analysis the EPR of FBR. Conclusion: A) the EPR of NPS in Japan is 17.4 and it is the best of all. B) Many countries will introduce new nuclear power plants rapidly may be 3.5 times in 2050. C) Uranium peak will happen around 2050. (author)

  15. Climatic and geographical dependence of the H, C and O stable isotope ratios of Italian wine

    Energy Technology Data Exchange (ETDEWEB)

    Camin, Federica, E-mail: federica.camin@fmach.it [Research and Innovation Centre, Fondazione Edmund Mach, via Mach 1, 38010 San Michele all' Adige (Italy); Dordevic, Nikola [Research and Innovation Centre, Fondazione Edmund Mach, via Mach 1, 38010 San Michele all' Adige (Italy); Radboud University Nijmegen, Institute for Molecules and Materials, Analytical Chemistry, P.O. Box 9010, 6500 GL Nijmegen (Netherlands); Wehrens, Ron; Neteler, Markus; Delucchi, Luca [Research and Innovation Centre, Fondazione Edmund Mach, via Mach 1, 38010 San Michele all' Adige (Italy); Postma, Geert; Buydens, Lutgarde [Radboud University Nijmegen, Institute for Molecules and Materials, Analytical Chemistry, P.O. Box 9010, 6500 GL Nijmegen (Netherlands)

    2015-01-01

    Graphical abstract: Correlation matrix between (D/H){sub 1}, (D/H){sub 2}, δ{sup 13}C and δ{sup 18}O parameters of wine (4000 samples) and the climatic and geographical characteristics of the areas of origin. - Highlights: • We studied the relationship between wine isotopic data and climate and geography. • We considered (D/H){sub 1}, (D/H){sub 2} and δ{sup 13}C of ethanol and δ{sup 18}O of water of 4000 wines. • δ{sup 18}O, followed by (D/H){sub 1}, had the strongest relationship with climate and location. • The dominant variables were latitude, δ{sup 18}O and δ{sup 2}H of precipitation and temperature. • Relationships and models may be used to predict the isotopic composition of wine. - Abstract: In this study, we investigated the relationship between (D/H){sub 1,} (D/H){sub 2} and δ{sup 13}C of ethanol and δ{sup 18}O of water in wine, and variables describing the climate and the geography of the production area, using exploratory visualisation tools, regression analysis and linear modelling. For the first time, a large amount of data (around 4000 wine samples collected over 11 years in Italy) and all the official isotopic parameters, as well as a large number of significant climatic and geographical descriptors (date of harvest, latitude, longitude, elevation, distance from the sea, amount of precipitation, maximum daily temperature, minimum daily temperature, mean daily temperature, δ{sup 18}O and δ{sup 2}H of precipitation) were considered. δ{sup 18}O, followed by (D/H){sub 1}, was shown to have the strongest relationship with climate and location. The dominant variables were latitude, with a negative relationship, δ{sup 18}O and δ{sup 2}H of precipitation and temperature, both with positive relationships. The identified correlations and models could be used to predict the isotopic composition of authentic wines, offering increased possibilities for detecting fraud and mislabelling.

  16. The relationship between stable oxygen and hydrogen isotope ratios of water in astomatal plants

    Science.gov (United States)

    Cooper, Lee W.; DeNiro, Michael J.; Keeley, Jon E.; Taylor, H. P.; O'Neil, J. R.; Kaplan, I.R.

    1991-01-01

    Isotropic fractination of leaf water during transpiration is influenced by both equilibrium and kinetic factors. Previous workers have predicted that the influence of each factor varies depending upon the path of water loss,m whether centralized through stomata, or diffuse through the cuticle. We studied the relationship between the δD and δ18O values of lead and stem waters of laurel sumac, Rhus laurina (Nutt.) T. & G., and its parasite, dodder, Cuscuta subinclusa D. & H., growing in the field. Stomatal transpiration, associated with more stagnant boundary layers, predominates in R. laurina; cuticular transpiration, associated with more turbulent boundary layers, is most important in the largely astomatal C. subinclusa. We also studied the diurnal variation in the δD and δ18O values of lead waters of two astomatal plants, Chiloschista lunifera (Rchb. F.) J.J.S. and Stylites andicola Amstutz, and two stomatal plants, Tillandsia balbisiana Schult. and Lilaeopsis schaffneriana (Schlecht.) C. & R., growing with them under the same conditions in the laboratory. Slopes, m, for the relation δD = mδ18O + b were significantly higher for stem waters in C. subinclusa that for leaf waters in R. laurina (1.77), consistent with the difference in the boundary layers through which water was lost in the two species. The magnitude of diurnal heavy isotope enrichment of tissue water was smaller in C. subinclusa than in R. laurina, which is also consistent with predictions concerning evapotranspiration through difference types of boundary layers. The slopes, m, in plant waters in the laboratory experiments, conducted at high humidity, were not different than those observed during evaporation of water from pans, regardless of plant anatomy. The observation suggests that cuticular transpiration is important in influencing isotopic fractionation of water only at low humidity. Our results indicate that the isotopic composition of water vapor released by plants in arid regions may be influenced by the relative proportions of stomatal versus cuticular transpiration.

  17. Stable carbon isotope ratios of lipid biomarkers and their applications in the marine environment

    International Nuclear Information System (INIS)

    Tolosa, I.; Mora, S. de

    2001-01-01

    Studies on the distribution of lipid biomarkers in the environment help elucidate biogeochemical processes, but recent findings have significantly reduced the specificity of some biomarkers. The analytical development of Gas Chromatography-Combustion-IRMS (GC-C-IRMS) allows the determination of the δ 13 C of specific biomarkers, thereby improving the veracity of source apportionment. In this report, we present a brief description of the analytical approach for sample preparation and carbon isotope measurements of individual biomarkers. Selected examples of the applications in the use of GC-C-IRMS for biomarker source elucidation in the marine environment and potential applications to paleoclimatological studies are reviewed. (author)

  18. Stable carbon isotopes in seagrasses: Variability in ratios and use in ecological studies

    NARCIS (Netherlands)

    Hemminga, M.A.; Mateo, M.A.

    1996-01-01

    Seagrass delta(13)C values reported in the Literature show variation over a range of approximately 20 parts per thousand. A frequency histogram constructed on the basis of the collected data set shows a unimodal distribution, with values between -10 and -11 parts per thousand (relative to the PDB

  19. Niche differentiation among neotropical soldierless soil-feeding termites revealed by stable isotope ratios

    Czech Academy of Sciences Publication Activity Database

    Bourguignon, T.; Šobotník, Jan; Lepoint, G.; Martin, J. M.; Roisin, Y.

    2009-01-01

    Roč. 41, č. 10 (2009), s. 2038-2043 ISSN 0038-0717 Institutional research plan: CEZ:AV0Z40550506 Keywords : Anoplotermes * Termitidae * Isoptera * resource partitioning Subject RIV: CC - Organic Chemistry Impact factor: 2.978, year: 2009

  20. Stable isotope ratio measurements on highly enriched water samples by means of laser spectrometry

    NARCIS (Netherlands)

    van Trigt, R; Kerstel, E.R.T.; Visser, GH; Meijer, H.A.J.

    2001-01-01

    We demonstrate the feasibility of using laser spectrometry (LS) to analyze isotopically highly enriched water samples (i.e., delta H-2 less than or equal to 15000 parts per thousand, delta O-18 less than or equal to 1200 parts per thousand), as often used in the biomedical doubly labeled water (DLW)

  1. Measurement of stable carbon isotope ratios of non-methane hydrocarbons and halocarbons

    NARCIS (Netherlands)

    Zuiderweg, A.T.

    2012-01-01

    Within the realm of volatile organic compounds, hydrocarbons and halocarbons form a sizable proportion of carbon input to the atmosphere. Within these compound categories, the light non-methane hydrocarbons (NMHC, two to seven carbon atoms) and monocarbon halocarbons have a special place as these

  2. A universal carbonate ion effect on stable oxygen isotope ratios in unicellular planktonic calcifying organisms

    OpenAIRE

    Ziveri, P.; Thoms, S.; Probert, I.; Geisen, M.; Langer, H.

    2012-01-01

    The oxygen isotopic composition (δ18O) of calcium carbonate of planktonic calcifying organisms is a key tool for reconstructing both past seawater temperature and salinity. The calibration of paloeceanographic proxies relies in general on empirical relationships derived from field experiments on extant species. Laboratory experiments have more often than not revealed that variables other than the target parameter influence the proxy signal, which makes proxy c...

  3. Stable nitrogen isotopic ratios of sinking particles and sediments from the northern Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Gaye-Haake, G.; Lahajnar, N.; Emeis, K.-Ch.; Unger, D.; Rixen, T.; Suthhof, A.; Ramaswamy, V.; Schulz, H.; Paropkari, A.L.; Guptha, M.V.S.; Ittekkot, V.

    from the Arabian Sea are correlated to the Degradation Index (DI), an indicator of amino acid degradation intensity, confirming the sensitivity of the delta sup(15)N to degradation. These results have to be considered for the interpretation of the delta...

  4. Assessing diet in savanna herbivores using stable carbon isotope ratios of faeces

    Directory of Open Access Journals (Sweden)

    D. Codron

    2005-06-01

    Full Text Available In African savannas, browse-based resources (@3 plants are isotopically distinct from grasses (@4 plants. The carbon isotopic composition of the basic plant diet is recorded in animal tissues. Mammal faeces are a readily accessible, non-invasive, sample material for temporally resolved dietary reconstructions. Faeces, however, include both undigested plant matter and waste, hence accuracy of dietary calculations could potentially be compromised by shifts in plant isotopic values related to seasonal or spatial differences, or by variability in the isotopic differences between faeces and diet. A controlled feeding study of four ungulate species showed a small, consistent difference between diet and faeces of-0.9 o, irrespective of whether the diet was @3 or C4-based. Results from faeces oftaxa known to be pure grazers, pure browsers, and mixed-feeders from the Kruger National Park were entirely consistent with their diets, but the accuracy of dietary reconstructions is enhanced with data from local plant communities.

  5. Climatic and geographical dependence of the H, C and O stable isotope ratios of Italian wine

    International Nuclear Information System (INIS)

    Camin, Federica; Dordevic, Nikola; Wehrens, Ron; Neteler, Markus; Delucchi, Luca; Postma, Geert; Buydens, Lutgarde

    2015-01-01

    Graphical abstract: Correlation matrix between (D/H) 1 , (D/H) 2 , δ 13 C and δ 18 O parameters of wine (4000 samples) and the climatic and geographical characteristics of the areas of origin. - Highlights: • We studied the relationship between wine isotopic data and climate and geography. • We considered (D/H) 1 , (D/H) 2 and δ 13 C of ethanol and δ 18 O of water of 4000 wines. • δ 18 O, followed by (D/H) 1 , had the strongest relationship with climate and location. • The dominant variables were latitude, δ 18 O and δ 2 H of precipitation and temperature. • Relationships and models may be used to predict the isotopic composition of wine. - Abstract: In this study, we investigated the relationship between (D/H) 1, (D/H) 2 and δ 13 C of ethanol and δ 18 O of water in wine, and variables describing the climate and the geography of the production area, using exploratory visualisation tools, regression analysis and linear modelling. For the first time, a large amount of data (around 4000 wine samples collected over 11 years in Italy) and all the official isotopic parameters, as well as a large number of significant climatic and geographical descriptors (date of harvest, latitude, longitude, elevation, distance from the sea, amount of precipitation, maximum daily temperature, minimum daily temperature, mean daily temperature, δ 18 O and δ 2 H of precipitation) were considered. δ 18 O, followed by (D/H) 1 , was shown to have the strongest relationship with climate and location. The dominant variables were latitude, with a negative relationship, δ 18 O and δ 2 H of precipitation and temperature, both with positive relationships. The identified correlations and models could be used to predict the isotopic composition of authentic wines, offering increased possibilities for detecting fraud and mislabelling

  6. LBA-ECO CD-02 Carbon, Nitrogen, Oxygen Stable Isotopes in Organic Material, Brazil

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set reports the measurement of stable carbon, nitrogen, and oxygen isotope ratios in organic material (plant, litter and soil samples) in forest canopy...

  7. LBA-ECO CD-02 Carbon, Nitrogen, Oxygen Stable Isotopes in Organic Material, Brazil

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set reports the measurement of stable carbon, nitrogen, and oxygen isotope ratios in organic material (plant, litter and soil samples) in forest...

  8. BASIN TCP Stable Isotope Composition of CO2 in Terrestrial Ecosystems

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set reports stable isotope ratio data of CO2 (13C/12C and 18O/16O) associated with photosynthetic and respiratory exchanges across the biosphere-atmosphere...

  9. BASIN TCP Stable Isotope Composition of CO2 in Terrestrial Ecosystems

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set reports stable isotope ratio data of CO2 (13C/12C and 18O/16O) associated with photosynthetic and respiratory exchanges across the...

  10. Insight into the structures and stabilities of Tc and Re DMSA complexes: A computational study

    International Nuclear Information System (INIS)

    Blanco González, Alejandro; Hernández Valdés, Daniel; García Fleitas, Ariel; Rodríguez Riera, Zalua; Jáuregui Haza, Ulises

    2016-01-01

    Meso-2,3-dimercaptosuccinic acid (DMSA) is used in nuclear medicine as ligand for preparation of radiopharmaceuticals for diagnostic and therapy. DMSA has been the subject of numerous investigations during the past three decades and new and significant information of the chemistry and pharmacology of DMSA complexes have emerged. In comparison to other ligands, the structure of some DMSA complexes is unclear up today. The structures and applications of DMSA complexes are strictly dependent on the chemical conditions of their preparation, especially pH and the ratio of components. A computational study of M-DMSA (M = Tc, Re) complexes has been performed using density functional theory. Different isomers for M(V) and M(III) complexes were study. The pH influence over ligand structures was taken into account and the solvent effect was evaluated using an implicit solvation model. The fully optimized complex syn-endo Re(V)-DMSA shows a geometry similar to the X-ray data and was used to validate the methodology. Moreover, new alternative structures for the renal agent 99mTc(III)-DMSA were proposed and computationally studied. For two complex structures, a larger stability respect to that proposed in the literature was obtained. Furthermore, Tc(V)-DMSA complexes are more stable than the Tc(III)-DMSA proposed structures. In general, Re complexes are more stables than the corresponding Tc ones. (author)

  11. Analytical system for stable carbon isotope measurements of low molecular weight (C2-C6 hydrocarbons

    Directory of Open Access Journals (Sweden)

    T. Röckmann

    2011-06-01

    Full Text Available We present setup, testing and initial results from a new automated system for stable carbon isotope ratio measurements on C2 to C6 atmospheric hydrocarbons. The inlet system allows analysis of trace gases from air samples ranging from a few liters for urban samples and samples with high mixing ratios, to many tens of liters for samples from remote unpolluted regions with very low mixing ratios. The centerpiece of the sample preparation is the separation trap, which is used to separate CO2 and methane from the compounds of interest. The main features of the system are (i the capability to sample up to 300 l of air, (ii long term (since May 2009 operational δ13C accuracy levels in the range 0.3–0.8 ‰ (1-σ, and (iii detection limits of order 1.5–2.5 ngC (collected amount of substance for all reported compounds. The first application of this system was the analysis of 21 ambient air samples taken during 48 h in August 2009 in Utrecht, the Netherlands. Results obtained are generally in good agreement with those from similar urban ambient air studies. Short sample intervals allowed by the design of the instrument help to illustrate the complex diurnal behavior of hydrocarbons in an urban environment, where diverse sources, dynamical processes, and chemical reactions are present.

  12. Properties of aqueous dispersion of chitosan and chondroitin sulfate complex derived from aquatic organisms

    Directory of Open Access Journals (Sweden)

    Novikov V. Yu.

    2016-09-01

    Full Text Available Investigation of production of chondroitin sulfate, chitosan and polyelectrolyte complexes based on them received from the local marine raw materials is relevant from the point of view of developing a comprehensive waste-free technology for natural raw materials processing. The objects of study are chitosan derived from the shell of the Kamchatka crab Paralithodes camtschaticus and chondroitin sulfate derived from cartilage of salmon Salmon salar. To determine the surface tension of polyelectrolyte complex solutions and dispersions the Wilhelmy method has been used, the effective radius of particle dispersion has been calculated by light scattering, measurements of effective viscosity have been carried out under shear deformation. The conditions of formation, surface and rheological properties of the chitosan and chondroitin sulfate complex extracted from aquatic organisms in the Barents Sea have been studied. Obtaining conditions and molar ratios of these polyelectrolytes in which the aqueous dispersion of the complex remains stable for a long time have been established. It has been found that by addition of chondroitin sulfate solution to chitosan solution in molar ratios of 1 : 3; 1 : 6 the dispersion of the polyelectrolyte complex stable for 2 to 3 days has been formed. The polyelectrolyte complex dispersions behave as non-Newtonian pseudoplastic liquid. When the molar ratio of the mixed solution is 1 : 1 (regardless of the sequence of mixing suspension of the polyelectrolyte complex has been formed, then there is precipitation. Equilibrium surface tension of the aqueous dispersion of the polyelectrolyte complex is higher than that of solutions of chondroitin sulfate and chitosan. The effective radius of particles in the complex dispersion has been determined. The effective radius of the particles in the complex dispersion depends on the molar ratio of chondroitin sulfate : chitosan. A qualitative scheme of formation of polyelectrolyte

  13. Stable radio frequency dissemination by simple hybrid frequency modulation scheme.

    Science.gov (United States)

    Yu, Longqiang; Wang, Rong; Lu, Lin; Zhu, Yong; Wu, Chuanxin; Zhang, Baofu; Wang, Peizhang

    2014-09-15

    In this Letter, we propose a fiber-based stable radio frequency transfer system by a hybrid frequency modulation scheme. Creatively, two radio frequency signals are combined and simultaneously transferred by only one laser diode. One frequency component is used to detect the phase fluctuation, and the other one is the derivative compensated signal providing a stable frequency for the remote end. A proper ratio of the frequencies of the components is well maintained by parameter m to avoid interference between them. Experimentally, a stable 200 MHz signal is transferred over 100 km optical fiber with the help of a 1 GHz detecting signal, and fractional instability of 2×10(-17) at 10(5) s is achieved.

  14. High precision and stable structures for particle detectors

    CERN Document Server

    Da Mota Silva, S; Hauviller, Claude

    1999-01-01

    The central detectors used in High Energy Physics Experiments require the use of light and stable structures capable of supporting delicate and precise radiation detection elements. These structures need to be highly stable under environmental conditions where external vibrations, high radiation levels, temperature and humidity gradients should be taken into account. Their main design drivers are high dimension and dynamic stability, high stiffness to mass ratio and large radiation length. For most applications, these constraints lead us to choose Carbon Fiber Reinforced Plastics ( CFRP) as structural element. The construction of light and stable structures with CFRP for these applications can be achieved by careful design engineering and further confirmation at the prototyping phase. However, the experimental environment can influence their characteristics and behavior. In this case, theuse of adaptive structures could become a solution for this problem. We are studying structures in CFRP with bonded piezoel...

  15. Application of enriched stable isotopes as tracers in biological systems

    DEFF Research Database (Denmark)

    Stürup, Stefan; Hansen, Helle Rüsz; Gammelgaard, Bente

    2008-01-01

    The application of enriched stable isotopes of minerals and trace elements as tracers in biological systems is a rapidly growing research field that benefits from the many new developments in inorganic mass spectrometric instrumentation, primarily within inductively coupled plasma mass spectrometry...... (ICP-MS) instrumentation, such as reaction/collision cell ICP-MS and multicollector ICP-MS with improved isotope ratio measurement and interference removal capabilities. Adaptation and refinement of radioisotope tracer experiment methodologies for enriched stable isotope experiments......, and the development of new methodologies coupled with more advanced compartmental and mathematical models for the distribution of elements in living organisms has enabled a broader use of enriched stable isotope experiments in the biological sciences. This review discusses the current and future uses of enriched...

  16. Organic synthesis with stable isotopes

    International Nuclear Information System (INIS)

    Daub, G.H.; Kerr, V.N.; Williams, D.L.; Whaley, T.W.

    1978-01-01

    Some general considerations concerning organic synthesis with stable isotopes are presented. Illustrative examples are described and discussed. The examples include DL-2-amino-3-methyl- 13 C-butanoic-3,4- 13 C 2 acid (DL-valine- 13 C 3 ); methyl oleate-1- 13 C; thymine-2,6- 13 C 2 ; 2-aminoethanesulfonic- 13 C acid (taurine- 13 C); D-glucose-6- 13 C; DL-2-amino-3-methylpentanoic-3,4- 13 C 2 acid (DL-isoleucine- 13 C 2 ); benzidine- 15 N 2 ; and 4-ethylsulfonyl-1-naphthalene-sulfonamide- 15 N

  17. Stable isotopes - separation and application

    International Nuclear Information System (INIS)

    Lockhart, I.M.

    1980-01-01

    In this review, methods used for the separation of stable isotopes ( 12 C, 13 C, 14 N, 15 N, 16 O, 17 O, 18 O, 34 S) will be described. The synthesis of labelled compounds, techniques for detection and assay, and areas of application will also be discussed. Particular attention will be paid to the isotopes of carbon, nitrogen, and oxygen; to date, sulphur isotopes have only assumed a minor role. The field of deuterium chemistry is too extensive for adequate treatment; it will therefore be essentially excluded. (author)

  18. Stable agents for imaging investigations

    International Nuclear Information System (INIS)

    Tofe, A.J.

    1976-01-01

    This invention concerns highly stable compounds useful in preparing technetium 99m based scintiscanning exploration agents. The compounds of this invention include a pertechnetate reducing agent or a solution of oxidized pertechnetate and an efficient proportion, sufficient to stabilize the compounds in the presence of oxygen and of radiolysis products, of ascorbic acid or a pharmaceutically acceptable salt or ester of this acid. The invention also concerns a perfected process for preparing a technetium based exploration agent, consisting in codissolving the ascorbic acid or a pharmaceutically acceptable salt or ester of such an acid and a pertechnetate reducing agent in a solution of oxidized pertechnetate [fr

  19. Stable platinum isotope measurements in presolar nanodiamonds by TEAMS

    Energy Technology Data Exchange (ETDEWEB)

    Wallner, A., E-mail: anton.wallner@univie.ac.at [University of Vienna, Faculty of Physics, VERA Laboratory, Waehringer Strasse 17, A-1090 Vienna (Austria); Department of Nuclear Physics, Research School of Physics and Engineering, Australian National University, Canberra (Australia); Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights (Australia); Melber, K. [University of Vienna, Faculty of Physics, VERA Laboratory, Waehringer Strasse 17, A-1090 Vienna (Austria); Merchel, S. [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), D-01314 Dresden (Germany); Ott, U. [Max-Planck-Institut fuer Chemie, Joh.-J.-Becherweg 27, D-55128 Mainz (Germany); Forstner, O.; Golser, R.; Kutschera, W.; Priller, A.; Steier, P. [University of Vienna, Faculty of Physics, VERA Laboratory, Waehringer Strasse 17, A-1090 Vienna (Austria)

    2013-01-15

    Nanodiamonds are stardust grains commonly found in primitive meteorites. They survived the formation of the solar system and kept their own individuality. Measurements of trace-element isotopic signatures in these grains will help understanding heavy element nucleosynthesis in massive stars and dust formation from their ejecta. We have continued previous attempts to search for stable Pt isotope anomalies in nanodiamonds via trace element accelerator mass spectrometry (TEAMS). The installation of a new injector beam line at the VERA facility allowed studying low traces of stable elements in different materials. Moreover, recent experiments showed that VERA provides the required measurement precision together with a low Pt machine background. Here, we observed for the first time an indication for enhancements of {sup 198}Pt/{sup 195}Pt isotope ratios in two diamond residues prepared by different chemical separation techniques from the Allende meteorite. Variations in other isotopic ratios were within analytical uncertainty, and no anomaly was identified in a third diamond fraction.

  20. Stable platinum isotope measurements in presolar nanodiamonds by TEAMS

    International Nuclear Information System (INIS)

    Wallner, A.; Melber, K.; Merchel, S.; Ott, U.; Forstner, O.; Golser, R.; Kutschera, W.; Priller, A.; Steier, P.

    2013-01-01

    Nanodiamonds are stardust grains commonly found in primitive meteorites. They survived the formation of the solar system and kept their own individuality. Measurements of trace-element isotopic signatures in these grains will help understanding heavy element nucleosynthesis in massive stars and dust formation from their ejecta. We have continued previous attempts to search for stable Pt isotope anomalies in nanodiamonds via trace element accelerator mass spectrometry (TEAMS). The installation of a new injector beam line at the VERA facility allowed studying low traces of stable elements in different materials. Moreover, recent experiments showed that VERA provides the required measurement precision together with a low Pt machine background. Here, we observed for the first time an indication for enhancements of 198 Pt/ 195 Pt isotope ratios in two diamond residues prepared by different chemical separation techniques from the Allende meteorite. Variations in other isotopic ratios were within analytical uncertainty, and no anomaly was identified in a third diamond fraction.

  1. Canonical, stable, general mapping using context schemes.

    Science.gov (United States)

    Novak, Adam M; Rosen, Yohei; Haussler, David; Paten, Benedict

    2015-11-15

    Sequence mapping is the cornerstone of modern genomics. However, most existing sequence mapping algorithms are insufficiently general. We introduce context schemes: a method that allows the unambiguous recognition of a reference base in a query sequence by testing the query for substrings from an algorithmically defined set. Context schemes only map when there is a unique best mapping, and define this criterion uniformly for all reference bases. Mappings under context schemes can also be made stable, so that extension of the query string (e.g. by increasing read length) will not alter the mapping of previously mapped positions. Context schemes are general in several senses. They natively support the detection of arbitrary complex, novel rearrangements relative to the reference. They can scale over orders of magnitude in query sequence length. Finally, they are trivially extensible to more complex reference structures, such as graphs, that incorporate additional variation. We demonstrate empirically the existence of high-performance context schemes, and present efficient context scheme mapping algorithms. The software test framework created for this study is available from https://registry.hub.docker.com/u/adamnovak/sequence-graphs/. anovak@soe.ucsc.edu Supplementary data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  2. Stable cosmology in chameleon bigravity

    Science.gov (United States)

    De Felice, Antonio; Mukohyama, Shinji; Oliosi, Michele; Watanabe, Yota

    2018-02-01

    The recently proposed chameleonic extension of bigravity theory, by including a scalar field dependence in the graviton potential, avoids several fine-tunings found to be necessary in usual massive bigravity. In particular it ensures that the Higuchi bound is satisfied at all scales, that no Vainshtein mechanism is needed to satisfy Solar System experiments, and that the strong coupling scale is always above the scale of cosmological interest all the way up to the early Universe. This paper extends the previous work by presenting a stable example of cosmology in the chameleon bigravity model. We find a set of initial conditions and parameters such that the derived stability conditions on general flat Friedmann background are satisfied at all times. The evolution goes through radiation-dominated, matter-dominated, and de Sitter eras. We argue that the parameter space allowing for such a stable evolution may be large enough to encompass an observationally viable evolution. We also argue that our model satisfies all known constraints due to gravitational wave observations so far and thus can be considered as a unique testing ground of gravitational wave phenomenologies in bimetric theories of gravity.

  3. Stable Heavy Hadrons in ATLAS

    CERN Document Server

    Mackeprang, Rasmus

    2007-01-01

    Several extensions to the SM feature heavy long-lived particles with masses of O(10^2-10^3 GeV) and mean lifetimes fulfilling $CT \\geq 10m$. Among such theories are supersymmetric scenarios as well as extra-dimensional models in which the heavy new particles are seen as Kaluza-Klein excitations of the well-known SM particles. Such particles will, from the point of view of a collider experiment be seen as stable. This thesis is concerned with the case where the exotic heavy particles emph{can} be considered stable while traversing the detector. Specifically the case is considered where the particles in question carry the charge of the strong nuclear force, commonly referred to as emph{colour charge}. A simulation kit has been developed using GEANT4. This framework is the current standard in experimental particle physics for the simulation of interactions of particles with matter, and it is used extensively for detector simulation. The simulation describes the interactions of these particles with matter which i...

  4. Stable isotope utilization for research on human nutrition

    International Nuclear Information System (INIS)

    Desjeux, J.F.

    1994-01-01

    In the framework of nutritional molecule metabolism research, this paper presents the various stable isotopes used as labels for biological molecules, the reasons for their application in human nutritional study (mainly because of their non toxicity) and the various analysis methods (isotope ratio mass spectrometry, coupled gaseous chromatography and mass spectrometry, nuclear magnetic resonance). Several application examples in nutrition research are then discussed: metabolic conversion measurement for a molecule into its different metabolites, energetic losses. 23 refs

  5. Development of Stable Solidification Method for Insoluble Ferrocyanides-13170

    Energy Technology Data Exchange (ETDEWEB)

    Ikarashi, Yuki; Masud, Rana Syed; Mimura, Hitoshi [Dept. of Quantum Science and Energy Engineering, Graduate School of Engineering, Tohoku University, Aramaki-Aza-Aoba6-6-01-2, Sendai, 980-8579 (Japan); Ishizaki, Eiji; Matsukura, Minoru [UNION SHOWA K.K. 17-20, Mita 2-chome, Minato-ku, Tokyo 108-0073 (Japan)

    2013-07-01

    The development of stable solidification method of insoluble ferrocyanides sludge is an important subject for the safety decontamination in Fukushima NPP-1. By using the excellent immobilizing properties of zeolites such as gas trapping ability and self-sintering properties, the stable solidification of insoluble ferrocyanides was accomplished. The immobilization ratio of Cs for K{sub 2}[CoFe(CN){sub 6}].nH{sub 2}O saturated with Cs{sup +} ions (Cs{sub 2}[CoFe(CN){sub 6}].nH{sub 2}O) was estimated to be less than 0.1% above 1,000 deg. C; the adsorbed Cs{sup +} ions are completely volatilized. In contrast, the novel stable solid form was produced by the press-sintering of the mixture of Cs{sub 2}[CoFe(CN){sub 6}].nH{sub 2}O and zeolites at higher temperature of 1,000 deg. C and 1,100 deg. C; Cs volatilization and cyanide release were completely depressed. The immobilization ratio of Cs, under the mixing conditions of Cs{sub 2}[CoFe(CN){sub 6}].nH{sub 2}O:CP= 1:1 and calcining temperature: 1,000 deg. C, was estimated to be nearly 100%. As for the kinds of zeolites, natural mordenite (NM), clinoptilolite (CP) and Chabazite tended to have higher immobilization ratio compared to zeolite A. This may be due to the difference in the phase transformation between natural zeolites and synthetic zeolite A. In the case of the composites (K{sub 2-X}Ni{sub X/2}[NiFe(CN){sub 6}].nH{sub 2}O loaded natural mordenite), relatively high immobilization ratio of Cs was also obtained. This method using zeolite matrices can be applied to the stable solidification of the solid wastes of insoluble ferrocyanides sludge. (authors)

  6. Factors controlling stable isotope composition of European precipitation

    International Nuclear Information System (INIS)

    Rozanski, K.; Sonntag, C.; Muennich, K.O.

    1982-01-01

    The seasonal and spatial variations of stable isotope ratios in present day European precipitation are simulated with a simple multibox model of the mean west-east horizontal transport of the atmospheric water vapour across the European continent. Isotope fractionation during the formation of precipitation leads to an increasing depletion of heavy isotopes in the residual air moisture as it moves towards the centre of the continent. This isotopic depletion is partly compensated, particularly in summer, by evapotranspiration, which is assumed to transfer soil water into the atmosphere without isotope fractionation. The model estimates are based on horizontal water vapour flux data, varying seasonally between 88 and 130 kg m -1 s -1 for the Atlantic coast region, and on the monthly precipitation, evapotranspiration and surface air temperature data available for various locations in Europe. Both continental and seasonal temperature effects observed in the stable isotope composition of European precipitation are fairly well reproduced by the model. The calculations show that the isotopic composition of local precipitation is primarily controlled by regional scale processes, i.e. by the water vapour transport patterns into the continent, and by the average precipitation-evapotranspiration history of the air masses precipitating at a given place. Local parameters such as the surface and/or cloud base temperature or the amount of precipitation modify the isotope ratios only slightly. Implications of the model predictions for the interpretation of stable isotope ratios in earlier periods as they are preserved in ice cores and in groundwater are also discussed. (Auth.)

  7. Bonding Properties of a Novel Inorganometallic Complex, Ru(SnPh(3))(2)(CO)(2)(iPr-DAB) (iPr-DAB = N,N'-Diisopropyl-1,4-diaza-1,3-butadiene), and its Stable Radical-Anion, Studied by UV-Vis, IR, and EPR Spectroscopy, (Spectro-) Electrochemistry, and Density Functional Calculations.

    Science.gov (United States)

    Aarnts, Maxim P.; Wilms, Maikel P.; Peelen, Karin; Fraanje, Jan; Goubitz, Kees; Hartl, Frantisek; Stufkens, Derk J.; Baerends, Evert Jan; Vlcek, Antonín

    1996-09-11

    Ru(SnPh(3))(2)(CO)(2)(iPr-DAB) was synthesized and characterized by UV-vis, IR, (1)H NMR, (13)C NMR, (119)Sn NMR, and mass (FAB(+)) spectroscopies and by single-crystal X-ray diffraction, which proved the presence of a nearly linear Sn-Ru-Sn unit. Crystals of Ru(SnPh(3))(2)(CO)(2)(iPr-DAB).3.5C(6)H(6) form in the triclinic space group P&onemacr; in a unit cell of dimensions a = 11.662(6) Å, b = 13.902(3) Å, c = 19.643(2) Å, alpha = 71.24(2) degrees, beta = 86.91(4) degrees, gamma = 77.89(3) degrees, and V = 2946(3) Å(3). One-electron reduction of Ru(SnPh(3))(2)(CO)(2)(iPr-DAB) produces the stable radical-anion [Ru(SnPh(3))(2)(CO)(2)(iPr-DAB)](*-) that was characterized by IR, and UV-vis spectroelectrochemistry. Its EPR spectrum shows a signal at g = 1.9960 with well resolved Sn, Ru, and iPr-DAB (H, N) hyperfine couplings. DFT-MO calculations on the model compound Ru(SnH(3))(2)(CO)(2)(H-DAB) reveal that the HOMO is mainly of sigma(Sn-Ru-Sn) character mixed strongly with the lowest pi orbital of the H-DAB ligand. The LUMO (SOMO in the reduced complex) should be viewed as predominantly pi(H-DAB) with an admixture of the sigma(Sn-Ru-Sn) orbital. Accordingly, the lowest-energy absorption band of the neutral species will mainly belong to the sigma(Sn-Ru-Sn)-->pi(iPr-DAB) charge transfer transition. The intrinsic strength of the Ru-Sn bond and the delocalized character of the three-center four-electron Sn-Ru-Sn sigma-bond account for the inherent stability of the radical anion.

  8. Formation of Polyelectrolyte Complex Colloid Particles between Chitosan and Pectin with Different Degree of Esterification

    Science.gov (United States)

    Wang, Hui; Sun, Hongyuan; He, Jieyu

    2017-12-01

    The effects of degree of esterification, pectin/chitosan ratio and pH on the formation of polyelectrolyte complex colloid particles between chitosan (CS) and pectin (PE) were investigated. Low methoxyl pectin (LPE) was achieved by de-esterifying high methoxyl pectin (HPE) with pectin methyl esterase. Turbidity titration and colorimetric method was used to determine the stability of complex colloid particles. The structure and morphology of complex particles were characterized by FTIR and TEM. When pectin solution was dropped into chitosan solution, complex colloidal dispersion was stable as PE/CS mass ratio was no more than 3:2. Colloidal particles of HPE-CS complex coagulated at larger ratio of PE/CS than LPE-CS. The maximum complex occurred at pH 6.1 for HPE-CS and pH 5.7 for LPE-CS, and decreasing pH leaded to the dissociation of complex particles. Electrostatic interactions between carboxyl groups on pectin and amino groups on chitosan were confirmed by FTIR. Colloidal particle sizes ranged from about 100 nm to 400 nm with spherical shape.

  9. Serial binary interval ratios improve rhythm reproduction.

    Science.gov (United States)

    Wu, Xiang; Westanmo, Anders; Zhou, Liang; Pan, Junhao

    2013-01-01

    Musical rhythm perception is a natural human ability that involves complex cognitive processes. Rhythm refers to the organization of events in time, and musical rhythms have an underlying hierarchical metrical structure. The metrical structure induces the feeling of a beat and the extent to which a rhythm induces the feeling of a beat is referred to as its metrical strength. Binary ratios are the most frequent interval ratio in musical rhythms. Rhythms with hierarchical binary ratios are better discriminated and reproduced than rhythms with hierarchical non-binary ratios. However, it remains unclear whether a superiority of serial binary over non-binary ratios in rhythm perception and reproduction exists. In addition, how different types of serial ratios influence the metrical strength of rhythms remains to be elucidated. The present study investigated serial binary vs. non-binary ratios in a reproduction task. Rhythms formed with exclusively binary (1:2:4:8), non-binary integer (1:3:5:6), and non-integer (1:2.3:5.3:6.4) ratios were examined within a constant meter. The results showed that the 1:2:4:8 rhythm type was more accurately reproduced than the 1:3:5:6 and 1:2.3:5.3:6.4 rhythm types, and the 1:2.3:5.3:6.4 rhythm type was more accurately reproduced than the 1:3:5:6 rhythm type. Further analyses showed that reproduction performance was better predicted by the distribution pattern of event occurrences within an inter-beat interval, than by the coincidence of events with beats, or the magnitude and complexity of interval ratios. Whereas rhythm theories and empirical data emphasize the role of the coincidence of events with beats in determining metrical strength and predicting rhythm performance, the present results suggest that rhythm processing may be better understood when the distribution pattern of event occurrences is taken into account. These results provide new insights into the mechanisms underlining musical rhythm perception.

  10. Serial binary interval ratios improve rhythm reproduction

    Directory of Open Access Journals (Sweden)

    Xiang eWu

    2013-08-01

    Full Text Available Musical rhythm perception is a natural human ability that involves complex cognitive processes. Rhythm refers to the organization of events in time, and musical rhythms have an underlying hierarchical metrical structure. The metrical structure induces the feeling of a beat and the extent to which a rhythm induces the feeling of a beat is referred to as its metrical strength. Binary ratios are the most frequent interval ratio in musical rhythms. Rhythms with hierarchical binary ratios are better discriminated and reproduced than rhythms with hierarchical non-binary ratios. However, it remains unclear whether a superiority of serial binary over non-binary ratios in rhythm perception and reproduction exists. In addition, how different types of serial ratios influence the metrical strength of rhythms remains to be elucidated. The present study investigated serial binary vs. non-binary ratios in a reproduction task. Rhythms formed with exclusively binary (1:2:4:8, non-binary integer (1:3:5:6, and non-integer (1:2.3:5.3:6.4 ratios were examined within a constant meter. The results showed that the 1:2:4:8 rhythm type was more accurately reproduced than the 1:3:5:6 and 1:2.3:5.3:6.4 rhythm types, and the 1:2.3:5.3:6.4 rhythm type was more accurately reproduced than the 1:3:5:6 rhythm type. Further analyses showed that reproduction performance was better predicted by the distribution pattern of event occurrences within an inter-beat interval, than by the coincidence of events with beats, or the magnitude and complexity of interval ratios. Whereas rhythm theories and empirical data emphasize the role of the coincidence of events with beats in determining metrical strength and predicting rhythm performance, the present results suggest that rhythm processing may be better understood when the distribution pattern of event occurrences is taken into account. These results provide new insights into the mechanisms underlining musical rhythm perception.

  11. Model of the transverse modes of stable and unstable porro–prism resonators using symmetry considerations

    CSIR Research Space (South Africa)

    Burger, L

    2007-01-01

    Full Text Available of this type of resonator. Further use of the model reveals the formation of more complex beam patterns, and the nature of these patterns is investigated. Also, the output of stable and unstable resonator modes is presented....

  12. Stable isotopes as tracers for radionuclides

    International Nuclear Information System (INIS)

    Giussani, A.; Bartolo, D. de; Cantone, M.C.; Zilker, T.; Greim, H.; Roth, P.; Werner, E.

    2000-01-01

    The assessment of internal dose after incorporation of radionuclides requires as input data the knowledge of the uptake into the systemic circulation, the distribution and retention in selected organs, the excretion pathways. Realistic biokinetic models are needed for reliable estimates, correct interpretation of bioassay measurements, appropriate decision-making in radiological emergencies. For many radionuclides, however, the biokinetic models currently recommended are often generic, with very few specific parameters, due to the lack of experimental human data. The use of stable isotopes as tracers enables to determine important biokinetic parameters such as the fractional uptake, the clearance from the transfer compartment, the excretion patterns under experimentally controlled conditions. The subjects investigated are not exposed to any radiation risk, so this technique enables to obtain biokinetic information also for sensitive groups of the population, such as children or pregnant women, and to determine age- and gender-specific model parameters. Sophisticated analytical method, able to discriminate and quantitate different isotopes of the same element in complex matrices such as biological fluids, have to be purposely developed and optimized. Activation analysis and mass spectrometry are the most proper techniques of choice. Experiments were conducted with molybdenum, tellurium, ruthenium and zirconium. Activation analysis with protons, thermal ionization mass spectrometry and inductively coupled mass spectrometry were employed for the determination of stable isotopes of these elements in blood plasma and urine samples. Several deviations from the predictions of the ICRP models were observed. For example, modifications to the current model for molybdenum have been suggested on the basis of these results. The dose coefficients to the target regions calculated with this proposed model are even of one order of magnitude different than the ICRP estimates

  13. Stable rotating dipole solitons in nonlocal media

    DEFF Research Database (Denmark)

    Lopez-Aguayo, Servando; Skupin, Stefan; Desyatnikov, Anton S.

    2006-01-01

    We present the first example of stable rotating two-soliton bound states in nonlinear optical media with nonlocal response. We show that, in contrast to media with local response, nonlocality opens possibilities to generate stable azimuthons.......We present the first example of stable rotating two-soliton bound states in nonlinear optical media with nonlocal response. We show that, in contrast to media with local response, nonlocality opens possibilities to generate stable azimuthons....

  14. Tempered stable laws as random walk limits

    OpenAIRE

    Chakrabarty, Arijit; Meerschaert, Mark M.

    2010-01-01

    Stable laws can be tempered by modifying the L\\'evy measure to cool the probability of large jumps. Tempered stable laws retain their signature power law behavior at infinity, and infinite divisibility. This paper develops random walk models that converge to a tempered stable law under a triangular array scheme. Since tempered stable laws and processes are useful in statistical physics, these random walk models can provide a basic physical model for the underlying physical phenomena.

  15. Stable States of Biological Organisms

    Science.gov (United States)

    Yukalov, V. I.; Sornette, D.; Yukalova, E. P.; Henry, J.-Y.; Cobb, J. P.

    2009-04-01

    A novel model of biological organisms is advanced, treating an organism as a self-consistent system subject to a pathogen flux. The principal novelty of the model is that it describes not some parts, but a biological organism as a whole. The organism is modeled by a five-dimensional dynamical system. The organism homeostasis is described by the evolution equations for five interacting components: healthy cells, ill cells, innate immune cells, specific immune cells, and pathogens. The stability analysis demonstrates that, in a wide domain of the parameter space, the system exhibits robust structural stability. There always exist four stable stationary solutions characterizing four qualitatively differing states of the organism: alive state, boundary state, critical state, and dead state.

  16. Super-stable Poissonian structures

    International Nuclear Information System (INIS)

    Eliazar, Iddo

    2012-01-01

    In this paper we characterize classes of Poisson processes whose statistical structures are super-stable. We consider a flow generated by a one-dimensional ordinary differential equation, and an ensemble of particles ‘surfing’ the flow. The particles start from random initial positions, and are propagated along the flow by stochastic ‘wave processes’ with general statistics and general cross correlations. Setting the initial positions to be Poisson processes, we characterize the classes of Poisson processes that render the particles’ positions—at all times, and invariantly with respect to the wave processes—statistically identical to their initial positions. These Poisson processes are termed ‘super-stable’ and facilitate the generalization of the notion of stationary distributions far beyond the realm of Markov dynamics. (paper)

  17. Super-stable Poissonian structures

    Science.gov (United States)

    Eliazar, Iddo

    2012-10-01

    In this paper we characterize classes of Poisson processes whose statistical structures are super-stable. We consider a flow generated by a one-dimensional ordinary differential equation, and an ensemble of particles ‘surfing’ the flow. The particles start from random initial positions, and are propagated along the flow by stochastic ‘wave processes’ with general statistics and general cross correlations. Setting the initial positions to be Poisson processes, we characterize the classes of Poisson processes that render the particles’ positions—at all times, and invariantly with respect to the wave processes—statistically identical to their initial positions. These Poisson processes are termed ‘super-stable’ and facilitate the generalization of the notion of stationary distributions far beyond the realm of Markov dynamics.

  18. Stable massive particles at colliders

    Energy Technology Data Exchange (ETDEWEB)

    Fairbairn, M.; /Stockholm U.; Kraan, A.C.; /Pennsylvania U.; Milstead, D.A.; /Stockholm U.; Sjostrand, T.; /Lund U.; Skands, P.; /Fermilab; Sloan, T.; /Lancaster U.

    2006-11-01

    We review the theoretical motivations and experimental status of searches for stable massive particles (SMPs) which could be sufficiently long-lived as to be directly detected at collider experiments. The discovery of such particles would address a number of important questions in modern physics including the origin and composition of dark matter in the universe and the unification of the fundamental forces. This review describes the techniques used in SMP-searches at collider experiments and the limits so far obtained on the production of SMPs which possess various colour, electric and magnetic charge quantum numbers. We also describe theoretical scenarios which predict SMPs, the phenomenology needed to model their production at colliders and interactions with matter. In addition, the interplay between collider searches and open questions in cosmology such as dark matter composition are addressed.

  19. Selenophene transition metal complexes

    Energy Technology Data Exchange (ETDEWEB)

    White, Carter James [Iowa State Univ., Ames, IA (United States)

    1994-07-27

    This research shows that selenophene transition metal complexes have a chemistry that is similar to their thiophene analogs. Selenophene coordination has been demonstrated and confirmed by molecular structure in both the η5- and the η1(Se)-coordination modes. The reaction chemistry of selenophene complexes closely resembles that of the analogous thiophene complexes. One major difference, however, is that selenophene is a better donor ligand than thiophene making the selenophene complexes more stable than the corresponding thiophene complexes. The 77Se NMR chemical shift values for selenophene complexes fall within distinct regions primarily depending on the coordination mode of the selenophene ligand. In the final paper, the C-H bond activation of η1(S)-bound thiophenes, η1(S)-benzothiophene and η1(Se)-bound selenophenes has been demonstrated. The deprotonation and rearrangement of the η1(E)-bound ligand to the carbon bound L-yl complex readily occurs in the presence of base. Reprotonation with a strong acid gives a carbene complex that is unreactive towards nucleophilic attack at the carbene carbon and is stable towards exposure to air. The molecular structure of [Cp(NO)(PPh3)Re(2-benzothioenylcarbene)]O3SCF3 was determined and contains a Re-C bond with substantial double bond character. Methyl substitution for the thienylcarbene or selenylcarbene gives a carbene that rearranges thermally to give back the η1(E)-bound complex. Based on these model reactions, a new mechanism for the H/D exchange of thiophene over the hydrodesulfurization catalyst has been proposed.

  20. The Myopic Stable Set for Social Environments

    NARCIS (Netherlands)

    Demuynck, Thomas; Herings, P. Jean-Jacques; Saulle, Riccardo; Seel, Christian

    2017-01-01

    We introduce a new solution concept for models of coalition formation, called the myopic stable set. The myopic stable set is defined for a very general class of social environments and allows for an infinite state space. We show that the myopic stable set exists and is non-empty. Under minor