Science.gov

Sample records for isotope snapshot application

  1. Snapshots

    NASA Astrophysics Data System (ADS)

    Smorodinskaya, Noemi

    It may sound too trivial, but it is very important that life consists of details. It becomes still more important when you are trying to get together the recollections using the details you remember. Snapshots render memorable moments in imperfect images. This is exactly what is presented below viewed by an external observer...

  2. Light-guide snapshot spectrometer for biomedical applications

    NASA Astrophysics Data System (ADS)

    Wang, Ye; Pawlowski, Michal E.; Tkaczyk, Tomasz S.

    2016-04-01

    We present a proof-of-principle prototype of a fiber-based snapshot spectrometer to provide high spatial and spectral sampling for biomedical application such as cell signaling or diagnostics. An image is collected by a custom fiber bundle and then divided into spatial groups with spaces in between for dispersion. The image is later scaled down by an image taper (to scale down the image size and allow smaller optical components), dispersed with a prism and captured by a CCD camera. An interpolation algorithm is used to locate each wavelength and reconstruct the image for each spectral channel. The fiber bundle is fabricated by aligning multi-mode bare fiber ribbons as matrix, gluing together in Teflon molds, laser cutting and polishing. We present preliminary finger occlusion results obtained with the spectrometer where the oxy- and deoxy-hemoglobin spectrum could be differentiated.

  3. Using satellite snapshots of aerosol optical depth to constrain biomass burning emissions for global model applications

    NASA Astrophysics Data System (ADS)

    Petrenko, M. M.; Kahn, R. A.; Chin, M.; Val Martin, M.

    2015-12-01

    Biomass burning (BB) is one of the major sources of optically and chemically potent carbonaceous aerosols, gaseous aerosol precursors, and volatile organic compounds. It is, therefore, important to represent these emissions as accurately as possible in the global and regional models. Based on our method of using satellite snapshot of aerosol optical depth (AOD) to constrain biomass burning emissions in the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model (Petrenko e t al., JGR 2012), we now present key refinements and applications of this method. In order to understand and possibly quantify the differences between global models in simulating BB emissions, our group is leading the Biomass Burning experiment within the Aerosol Comparison between Observations and Models (AEROCOM) framework. With 14 models currently participating, we are starting to work with the rich dataset of model output to compare several aspects of simulated Biomass Burning aerosols in these models. We will present a reference dataset of biomass burning cases constructed specifically for this project, initial findings from comparing total AOD and BB AOD between the models and with the reference satellite dataset, and mention future directions of this project. We will also showcase our approach for treating AOD snapshots to be suitable for comparison with the global models, and its potential applications to other BB-related projects.

  4. A four-dimensional snapshot hyperspectral video-endoscope for bio-imaging applications

    NASA Astrophysics Data System (ADS)

    Lim, Hoong-Ta; Murukeshan, Vadakke Matham

    2016-04-01

    Hyperspectral imaging has proven significance in bio-imaging applications and it has the ability to capture up to several hundred images of different wavelengths offering relevant spectral signatures. To use hyperspectral imaging for in vivo monitoring and diagnosis of the internal body cavities, a snapshot hyperspectral video-endoscope is required. However, such reported systems provide only about 50 wavelengths. We have developed a four-dimensional snapshot hyperspectral video-endoscope with a spectral range of 400-1000 nm, which can detect 756 wavelengths for imaging, significantly more than such systems. Capturing the three-dimensional datacube sequentially gives the fourth dimension. All these are achieved through a flexible two-dimensional to one-dimensional fiber bundle. The potential of this custom designed and fabricated compact biomedical probe is demonstrated by imaging phantom tissue samples in reflectance and fluorescence imaging modalities. It is envisaged that this novel concept and developed probe will contribute significantly towards diagnostic in vivo biomedical imaging in the near future.

  5. A four-dimensional snapshot hyperspectral video-endoscope for bio-imaging applications

    PubMed Central

    Lim, Hoong-Ta; Murukeshan, Vadakke Matham

    2016-01-01

    Hyperspectral imaging has proven significance in bio-imaging applications and it has the ability to capture up to several hundred images of different wavelengths offering relevant spectral signatures. To use hyperspectral imaging for in vivo monitoring and diagnosis of the internal body cavities, a snapshot hyperspectral video-endoscope is required. However, such reported systems provide only about 50 wavelengths. We have developed a four-dimensional snapshot hyperspectral video-endoscope with a spectral range of 400–1000 nm, which can detect 756 wavelengths for imaging, significantly more than such systems. Capturing the three-dimensional datacube sequentially gives the fourth dimension. All these are achieved through a flexible two-dimensional to one-dimensional fiber bundle. The potential of this custom designed and fabricated compact biomedical probe is demonstrated by imaging phantom tissue samples in reflectance and fluorescence imaging modalities. It is envisaged that this novel concept and developed probe will contribute significantly towards diagnostic in vivo biomedical imaging in the near future. PMID:27044607

  6. A four-dimensional snapshot hyperspectral video-endoscope for bio-imaging applications.

    PubMed

    Lim, Hoong-Ta; Murukeshan, Vadakke Matham

    2016-04-05

    Hyperspectral imaging has proven significance in bio-imaging applications and it has the ability to capture up to several hundred images of different wavelengths offering relevant spectral signatures. To use hyperspectral imaging for in vivo monitoring and diagnosis of the internal body cavities, a snapshot hyperspectral video-endoscope is required. However, such reported systems provide only about 50 wavelengths. We have developed a four-dimensional snapshot hyperspectral video-endoscope with a spectral range of 400-1000 nm, which can detect 756 wavelengths for imaging, significantly more than such systems. Capturing the three-dimensional datacube sequentially gives the fourth dimension. All these are achieved through a flexible two-dimensional to one-dimensional fiber bundle. The potential of this custom designed and fabricated compact biomedical probe is demonstrated by imaging phantom tissue samples in reflectance and fluorescence imaging modalities. It is envisaged that this novel concept and developed probe will contribute significantly towards diagnostic in vivo biomedical imaging in the near future.

  7. Nationwide Snapshot

    SciTech Connect

    Mapes, Terry S.; Iverson, Megan M.; Fassbender, Linda L.; Britt, Michelle L.

    2011-09-01

    The purpose of this effort was to create a nationwide snapshot of the current residential building practices in the United States, and to identify trends in building practices as they relate to building energy efficiency. Information on typical insulation levels, heating, ventilation, and air conditioning (HVAC) efficiencies, window profiles, and other residential building components and assemblies provided a foundation for (1) identifying trends in residential building practices over time, (2) assessing energy-efficiency improvements in single-family homes over time and correlating them with the applicable building energy codes if possible, and (3) identifying building energy code adoption and compliance needs. This report seeks to identify trends in the residential building practice from 1996 to 2009.

  8. Applications of stable isotopes in clinical pharmacology.

    PubMed

    Schellekens, Reinout C A; Stellaard, Frans; Woerdenbag, Herman J; Frijlink, Henderik W; Kosterink, Jos G W

    2011-12-01

    This review aims to present an overview of the application of stable isotope technology in clinical pharmacology. Three main categories of stable isotope technology can be distinguished in clinical pharmacology. Firstly, it is applied in the assessment of drug pharmacology to determine the pharmacokinetic profile or mode of action of a drug substance. Secondly, stable isotopes may be used for the assessment of drug products or drug delivery systems by determination of parameters such as the bioavailability or the release profile. Thirdly, patients may be assessed in relation to patient-specific drug treatment; this concept is often called personalized medicine. In this article, the application of stable isotope technology in the aforementioned three areas is reviewed, with emphasis on developments over the past 25 years. The applications are illustrated with examples from clinical studies in humans. © 2011 The Authors. British Journal of Clinical Pharmacology © 2011 The British Pharmacological Society.

  9. Applications of stable isotopes in clinical pharmacology

    PubMed Central

    Schellekens, Reinout C A; Stellaard, Frans; Woerdenbag, Herman J; Frijlink, Henderik W; Kosterink, Jos G W

    2011-01-01

    This review aims to present an overview of the application of stable isotope technology in clinical pharmacology. Three main categories of stable isotope technology can be distinguished in clinical pharmacology. Firstly, it is applied in the assessment of drug pharmacology to determine the pharmacokinetic profile or mode of action of a drug substance. Secondly, stable isotopes may be used for the assessment of drug products or drug delivery systems by determination of parameters such as the bioavailability or the release profile. Thirdly, patients may be assessed in relation to patient-specific drug treatment; this concept is often called personalized medicine. In this article, the application of stable isotope technology in the aforementioned three areas is reviewed, with emphasis on developments over the past 25 years. The applications are illustrated with examples from clinical studies in humans. PMID:21801197

  10. Photonics engineering: snapshot applications in healthcare, homeland security, agriculture, and industry

    NASA Astrophysics Data System (ADS)

    Sumriddetchkajorn, Sarun

    2015-01-01

    Throughout my experience in photonics engineering, this article shows that photonics is indeed a key technology enabler for enhancing our competitiveness. In particular, I snapshot the achievements of NECTEC research teams in implementing devices and systems suitable for healthcare, homeland security, agriculture, and industry.

  11. Selected scientific topics of the 11th International Isotope Symposium on the Synthesis and Applications of Isotopes and Isotopically Labeled Compounds.

    PubMed

    Atzrodt, Jens; Derdau, Volker

    2013-01-01

    This micro-review describes hot topics and new trends in isotope science discussed at the 11th International Isotope Symposium on the Synthesis and Applications of Isotopes and Isotopically Labeled Compounds from a personal perspective.

  12. Short course on St-02 applications of isotope dilutions and isotopic measurements

    SciTech Connect

    Miller, P.

    1998-01-05

    This short course includes information on these topics and subtopics: (I) Nuclear Properties: (A) Historic roots; (B) Nomenclature; (C) Nuclear Stability and abundance; (D) Uses of isotopic techniques; (II) Instrumentation: (A) Sources; (B) Mass resolving elements; (C) Detectors; (III) Making Isotopic Measurements by ICP-MS: (A) Deadtime Correction; (B) Mass Discrimination; (C) Signal /Noise considerations; (IV) Applications and examples: (A) Isotope dilution; (B) Double Spike; (C) Biological Application; (D) Environmental Application; (E) Geological.

  13. Special Application Thermoelectric Micro Isotope Power Sources

    SciTech Connect

    Heshmatpour, Ben; Lieberman, Al; Khayat, Mo; Leanna, Andrew; Dobry, Ted

    2008-01-21

    Promising design concepts for milliwatt (mW) size micro isotope power sources (MIPS) are being sought for use in various space and terrestrial applications, including a multitude of future NASA scientific missions and a range of military applications. To date, the radioisotope power sources (RPS) used on various space and terrestrial programs have provided power levels ranging from one-half to several hundred watts. In recent years, the increased use of smaller spacecraft and planned new scientific space missions by NASA, special terrestrial and military applications suggest the need for lower power, including mW level, radioisotope power sources. These power sources have the potential to enable such applications as long-lived meteorological or seismological stations distributed across planetary surfaces, surface probes, deep space micro-spacecraft and sub-satellites, terrestrial sensors, transmitters, and micro-electromechanical systems. The power requirements are in the range of 1 mW to several hundred mW. The primary technical requirements for space applications are long life, high reliability, high specific power, and high power density, and those for some special military uses are very high power density, specific power, reliability, low radiological induced degradation, and very low radiation leakage. Thermoelectric conversion is of particular interest because of its technological maturity and proven reliability. This paper summarizes the thermoelectric, thermal, and radioisotope heat source designs and presents the corresponding performance for a number of mW size thermoelectric micro isotope power sources.

  14. Triple Oxygen Isotopes: Fundamental Relationships and Applications

    NASA Astrophysics Data System (ADS)

    Bao, Huiming; Cao, Xiaobin; Hayles, Justin A.

    2016-06-01

    The element oxygen has three stable isotopes: 16O, 17O, and 18O. For a defined process, a change in 18O/16O scales with the corresponding change in 17O/16O, or the fractionation factors 18α and 17α have a relationship of θ = ln17α/ln18α, in which the triple oxygen isotope exponent θ is relatively fixed but does vary with reaction path, temperature, and species involved. When the small variation is of interest, the distinction of three concepts—θ, S (a slope through data points in δ17O-δ18O space), and C (an arbitrary referencing number for the degree of 17O deviation)—becomes important. Triple oxygen isotope variations can be measured by modern instruments and thus offer an additional line of information on the underlying reaction processes and conditions. Analytical methods and Earth science applications have recently been developed for air oxygen, carbon dioxide, water, silicates, oxides, sulfates, carbonates, and phosphates.

  15. Laser Isotope Enrichment for Medical and Industrial Applications

    SciTech Connect

    Leonard Bond

    2006-07-01

    Laser Isotope Enrichment for Medical and Industrial Applications by Jeff Eerkens (University of Missouri), Jay Kunze (Idaho State University), and Leonard Bond (Idaho National Laboratory) The principal isotope enrichment business in the world is the enrichment of uranium for commercial power reactor fuels. However, there are a number of other needs for separated isotopes. Some examples are: 1) Pure isotopic targets for irradiation to produce medical radioisotopes. 2) Pure isotopes for semiconductors. 3) Low neutron capture isotopes for various uses in nuclear reactors. 4) Isotopes for industrial tracer/identification applications. Examples of interest to medicine are targets to produce radio-isotopes such as S-33, Mo-98, Mo-100, W-186, Sn-112; while for MRI diagnostics, the non-radioactive Xe-129 isotope is wanted. For super-semiconductor applications some desired industrial isotopes are Si-28, Ga-69, Ge-74, Se-80, Te-128, etc. An example of a low cross section isotope for use in reactors is Zn-68 as a corrosion inhibitor material in nuclear reactor primary systems. Neutron activation of Ar isotopes is of interest in industrial tracer and diagnostic applications (e.g. oil-logging). . In the past few years there has been a sufficient supply of isotopes in common demand, because of huge Russian stockpiles produced with old electromagnetic and centrifuge separators previously used for uranium enrichment. Production of specialized isotopes in the USA has been largely accomplished using old ”calutrons” (electromagnetic separators) at Oak Ridge National Laboratory. These methods of separating isotopes are rather energy inefficient. Use of lasers for isotope separation has been considered for many decades. None of the proposed methods have attained sufficient proof of principal status to be economically attractive to pursue commercially. Some of the authors have succeeded in separating sulfur isotopes using a rather new and different method, known as condensation

  16. APPLICATIONS OF ENVIRONMENTAL ISOTOPES FOR WATERSHED INVESTIGATIONS

    EPA Science Inventory

    Environmental isotopes include naturally-occurring nuclides that can be applied as tracers within watersheds (Sidle, 1998). Recent advances in mass spectroscopy may supplant many traditional and costly hydrometric techniques. It is now possible, for example, to utilize isotopes a...

  17. Snapshots of Applications in Mathematics: Thermal Systems and the Solar Oven.

    ERIC Educational Resources Information Center

    Callas, Dennis, Ed.; Hildreth, David J., Ed.; Bickford, Carl

    1998-01-01

    Showcases applications of mathematics designed to demonstrate to students how the topics under study are used in the real world or to solve problems. Presents an activity on thermal systems using spreadsheets or graphing calculators. (ASK)

  18. Applications of stable isotope analysis in mammalian ecology.

    PubMed

    Walter, W David; Kurle, Carolyn M; Hopkins, John B

    2014-01-01

    In this editorial, we provide a brief introduction and summarize the 10 research articles included in this Special Issue on Applications of stable isotope analysis in mammalian ecology. The first three articles report correction and discrimination factors that can be used to more accurately estimate the diets of extinct and extant mammals using stable isotope analysis. The remaining seven applied research articles use stable isotope analysis to address a variety of wildlife conservation and management questions from the oceans to the mountains.

  19. Stable Isotope Applications in Hydrologic Studies

    NASA Astrophysics Data System (ADS)

    Kendall, C.; Doctor, D. H.

    2003-12-01

    The topic of stream flow generation has received considerable attention over the last two decades, first in response to concern about "acid rain" and more recently in response to the increasingly serious contamination of surface and shallow groundwaters by anthropogenic contaminants. Many sensitive, low-alkalinity streams in North America and Europe are already acidified (see Chapter 9.10). Still more streams that are not yet chronically acidic may undergo acidic episodes in response to large rainstorms and/or spring snowmelt. These acidic events can seriously damage local ecosystems. Future climate changes may exacerbate the situation by affecting biogeochemical controls on the transport of water, nutrients, and other materials from land to freshwater ecosystems.New awareness of the potential danger to water supplies posed by the use of agricultural chemicals and urban industrial development has also focused attention on the nature of rainfall-runoff and recharge processes and the mobility of various solutes, especially nitrate and pesticides, in shallow systems. Dumping and spills of other potentially toxic materials are also of concern because these chemicals may eventually reach streams and other public water supplies. A better understanding of hydrologic flow paths and solute sources is required to determine the potential impact of contaminants on water supplies, develop management practices to preserve water quality, and devise remediation plans for sites that are already polluted.Isotope tracers have been extremely useful in providing new insights into hydrologic processes, because they integrate small-scale variability to give an effective indication of catchment-scale processes. The main purpose of this chapter is to provide an overview of recent research into the use of naturally occurring stable isotopes to track the movement of water and solutes in hydrological systems where the waters are relatively fresh: soils, surface waters, and shallow

  20. Snapshot Hyperspectral Volumetric Microscopy

    PubMed Central

    Wu, Jiamin; Xiong, Bo; Lin, Xing; He, Jijun; Suo, Jinli; Dai, Qionghai

    2016-01-01

    The comprehensive analysis of biological specimens brings about the demand for capturing the spatial, temporal and spectral dimensions of visual information together. However, such high-dimensional video acquisition faces major challenges in developing large data throughput and effective multiplexing techniques. Here, we report the snapshot hyperspectral volumetric microscopy that computationally reconstructs hyperspectral profiles for high-resolution volumes of ~1000 μm × 1000 μm × 500 μm at video rate by a novel four-dimensional (4D) deconvolution algorithm. We validated the proposed approach with both numerical simulations for quantitative evaluation and various real experimental results on the prototype system. Different applications such as biological component analysis in bright field and spectral unmixing of multiple fluorescence are demonstrated. The experiments on moving fluorescent beads and GFP labelled drosophila larvae indicate the great potential of our method for observing multiple fluorescent markers in dynamic specimens. PMID:27103155

  1. Snapshot Hyperspectral Volumetric Microscopy

    NASA Astrophysics Data System (ADS)

    Wu, Jiamin; Xiong, Bo; Lin, Xing; He, Jijun; Suo, Jinli; Dai, Qionghai

    2016-04-01

    The comprehensive analysis of biological specimens brings about the demand for capturing the spatial, temporal and spectral dimensions of visual information together. However, such high-dimensional video acquisition faces major challenges in developing large data throughput and effective multiplexing techniques. Here, we report the snapshot hyperspectral volumetric microscopy that computationally reconstructs hyperspectral profiles for high-resolution volumes of ~1000 μm × 1000 μm × 500 μm at video rate by a novel four-dimensional (4D) deconvolution algorithm. We validated the proposed approach with both numerical simulations for quantitative evaluation and various real experimental results on the prototype system. Different applications such as biological component analysis in bright field and spectral unmixing of multiple fluorescence are demonstrated. The experiments on moving fluorescent beads and GFP labelled drosophila larvae indicate the great potential of our method for observing multiple fluorescent markers in dynamic specimens.

  2. Stable Chlorine Isotope Study: Application to Early Solar System Materials

    NASA Technical Reports Server (NTRS)

    Mala,ira. M/; Nyquist, L. E.; Reese, Y.; Shih, C-Y; Fujitani, T.; Okano, O.

    2010-01-01

    other [4], some authors have claimed that the 37Cl/35Cl ratio of geological samples obtained by TIMS technique are, in general, misleadingly too high and variable compared to those of IRMS [3]. For eample, almost no differences of Cl isotope composition were observed among mantle materials and carbonaceous meteorites by [3]. On the other hand, according to more recent IRMS work [2], significant Cl isotope variations are confirmed for mantle materials. Therefore, additional careful investigation of Cl isotope analyses are now required to confirm real chlorine isotope variations for planetary materials including carbonaceous chondrites [5]. In order to clarify the stable chlorine isotope features of early solar system materials, we have initiated development of the TIMS technique at NASA JSC applicable to analysis of small amounts of meteoritic and planetary materials. We report here the current status of chlorine isotope analysis at NASA JSC.

  3. Possible application of laser isotope separation

    NASA Technical Reports Server (NTRS)

    Delionback, L. M.

    1975-01-01

    The laser isotope separation process is described and its special economic features discussed. These features are its low cost electric power operation, capital investment costs, and the costs of process materials.

  4. Novel PEFC Application for Deuterium Isotope Separation.

    PubMed

    Matsushima, Hisayoshi; Ogawa, Ryota; Shibuya, Shota; Ueda, Mikito

    2017-03-16

    The use of a polymer electrolyte fuel cell (PEFC) with a Nafion membrane for isotopic separation of deuterium (D) was investigated. Mass analysis at the cathode side indicated that D diffused through the membrane and participated in an isotope exchange reaction. The exchange of D with protium (H) in H₂O was facilitated by a Pt catalyst. The anodic data showed that the separation efficiency was dependent on the D concentration in the source gas, whereby the water produced during the operation of the PEFC was more enriched in D as the D concentration of the source gas was increased.

  5. Novel PEFC Application for Deuterium Isotope Separation

    PubMed Central

    Matsushima, Hisayoshi; Ogawa, Ryota; Shibuya, Shota; Ueda, Mikito

    2017-01-01

    The use of a polymer electrolyte fuel cell (PEFC) with a Nafion membrane for isotopic separation of deuterium (D) was investigated. Mass analysis at the cathode side indicated that D diffused through the membrane and participated in an isotope exchange reaction. The exchange of D with protium (H) in H2O was facilitated by a Pt catalyst. The anodic data showed that the separation efficiency was dependent on the D concentration in the source gas, whereby the water produced during the operation of the PEFC was more enriched in D as the D concentration of the source gas was increased. PMID:28772661

  6. Medical applications of Cu, Zn, and S isotope effects.

    PubMed

    Albarede, Francis; Télouk, Philippe; Balter, Vincent; Bondanese, Victor P; Albalat, Emmanuelle; Oger, Philippe; Bonaventura, Paola; Miossec, Pierre; Fujii, Toshiyuki

    2016-10-01

    This review examines recent applications of stable copper, zinc and sulfur isotopes to medical cases and notably cancer. The distribution of the natural stable isotopes of a particular element among coexisting molecular species varies as a function of the bond strength, the ionic charge, and the coordination, and it also changes with kinetics. Ab initio calculations show that compounds in which a metal binds to oxygen- (sulfate, phosphate, lactate) and nitrogen-bearing moieties (histidine) favor heavy isotopes, whereas bonds with sulfur (cysteine, methionine) favor light isotopes. Oxidized cations (e.g., Cu(ii)) and low coordination numbers are expected to favor heavy isotopes relative to their reduced counterparts (Cu(i)) and high coordination numbers. Here we discuss the first observations of Cu, Zn, and S isotopic variations, three elements closely related along multiple biological pathways, with emphasis on serum samples of healthy volunteers and of cancer patients. It was found that heavy isotopes of Zn and to an even greater extent Cu are enriched in erythrocytes relative to serum, while the difference is small for sulfur. Isotopic variations related to age and sex are relatively small. The (65)Cu/(63)Cu ratio in the serum of patients with colon, breast, and liver cancer is conspicuously low relative to healthy subjects. The characteristic time over which Cu isotopes may change with disease progression (a few weeks) is consistent with both the turnover time of the element and albumin half-life. A parallel effect on sulfur isotopes is detected in a few un-medicated patients. Copper in liver tumor tissue is isotopically heavy. In contrast, Zn in breast cancer tumors is isotopically lighter than in healthy breast tissue. (66)Zn/(64)Zn is very similar in the serum of cancer patients and in controls. Possible reasons for Cu isotope variations may be related to the cytosolic storage of Cu lactate (Warburg effect), release of intracellular copper from cysteine

  7. Miniature snapshot multispectral imager

    NASA Astrophysics Data System (ADS)

    Gupta, Neelam; Ashe, Philip R.; Tan, Songsheng

    2011-03-01

    We present a miniature snapshot multispectral imager based on using a monolithic filter array that operates in the short wavelength infrared spectral region and has a number of defense and commercial applications. The system is low-weight, portable with a miniature platform, and requires low power. The imager uses a 4×4 Fabry-Pérot filter array operating from 1487 to 1769 nm with a spectral bandpass ~10 nm. The design of the filters is based on using a shadow mask technique to fabricate an array of Fabry-Pérot etalons with two multilayer dielectric mirrors. The filter array is installed in a commercial handheld InGaAs camera, replacing the imaging lens with a custom designed 4×4 microlens assembly with telecentric imaging performance in each of the 16 subimaging channels. We imaged several indoor and outdoor scenes. The microlens assembly and filter design is quite flexible and can be tailored for any wavelength region from the ultraviolet to the longwave infrared, and the spectral bandpass can also be customized to meet sensing requirements. In this paper we discuss the design and characterization of the filter array, the microlens optical assembly, and imager and present imaging results.

  8. MIR hollow waveguide (HWG) isotope ratio analyzer for environmental applications

    NASA Astrophysics Data System (ADS)

    Wang, Zhenyou; Zhuang, Yan; Deev, Andrei; Wu, Sheng

    2017-05-01

    An advanced commercial Mid-InfraRed Isotope Ratio (IR2) analyzer was developed in Arrow Grand Technologies based on hollow waveguide (HWG) as the sample tube. The stable carbon isotope ratio, i.e. δ13C, was obtained by measuring the selected CO2 absorption peaks in the MIR. Combined with a GC and a combustor, it has been successfully employed to measure compound specific δ13C isotope ratios in the field. By using both the 1- pass HWG and 5-path HWG, we are able to measure δ13C isotope ratio at a broad CO2 concentration of 300 ppm-37,500 ppm. Here, we demonstrate its applications in environmental studies. The δ13C isotope ratio and concentration of CO2 exhaled by soil samples was measured in real time with the isotope analyzer. The concentration was found to change with the time. We also convert the Dissolved Inorganic Carbon (DIC) into CO2, and then measure the δ13C isotope ratio with an accuracy of better than 0.3 ‰ (1 σ) with a 6 min test time and 1 ml sample usage. Tap water, NaHCO3 solvent, coca, and even beer were tested. Lastly, the 13C isotope ratio of CO2 exhaled by human beings was obtained <10 seconds after simply blowing the exhaled CO2 into a tube with an accuracy of 0.5‰ (1 σ) without sample preconditioning. In summary, a commercial HWG isotope analyzer was demonstrated to be able to perform environmental and health studies with a high accuracy ( 0.3 ‰/Hz1/2 1 σ), fast sampling rate (up to 10 Hz), low sample consumption ( 1 ml), and broad CO2 concentration range (300 ppm-37,500 ppm).

  9. Heavy element stable isotope ratios: analytical approaches and applications.

    PubMed

    Tanimizu, Masaharu; Sohrin, Yoshiki; Hirata, Takafumi

    2013-03-01

    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.

  10. APPLICATION OF STABLE ISOTOPE TECHNIQUES TO AIR POLLUTION RESEARCH

    EPA Science Inventory

    Stable isotope techniques provide a robust, yet under-utilized tool for examining pollutant effects on plant growth and ecosystem function. Here, we survey a range of mixing model, physiological and system level applications for documenting pollutant effects. Mixing model examp...

  11. APPLICATION OF STABLE ISOTOPE TECHNIQUES TO AIR POLLUTION RESEARCH

    EPA Science Inventory

    Stable isotope techniques provide a robust, yet under-utilized tool for examining pollutant effects on plant growth and ecosystem function. Here, we survey a range of mixing model, physiological and system level applications for documenting pollutant effects. Mixing model examp...

  12. 77 FR 38086 - Manufacturer of Controlled Substances, Notice of Application, Cambridge Isotope Lab

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-26

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF JUSTICE Drug Enforcement Administration Manufacturer of Controlled Substances, Notice of Application, Cambridge Isotope Lab... 7, 2012, Cambridge Isotope Lab, 50 Frontage Road, Andover, Massachusetts 01810, made application...

  13. 78 FR 52802 - Manufacturer of Controlled Substances; Notice of Application; Cambridge Isotope Lab

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-26

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF JUSTICE Drug Enforcement Administration Manufacturer of Controlled Substances; Notice of Application; Cambridge Isotope Lab... 01, 2013, Cambridge Isotope Lab, 50 Frontage Road, Andover, Massachusetts 01810, made application...

  14. Applications of isotopes in advancing structural and functional heparanomics.

    PubMed

    Tran, Vy M; Nguyen, Thao K N; Raman, Karthik; Kuberan, Balagurunathan

    2011-01-01

    Heparanomics is the study of all the biologically active oligosaccharide domain structures in the entire heparanome and the nature of the interactions among these domains and their protein ligands. Structural elucidation of heparan sulfate and heparin oligosaccharides is a major obstacle in advancing structure-function relationships and heparanomics. There are several factors that exacerbate the challenges involved in the structural elucidation of heparin and heparan sulfate; therefore, there is great interest in developing novel strategies and analytical tools to overcome the barriers in decoding the enigmatic heparanome. This review focuses on the applications of isotopes, both radioisotopes and stable isotopes, in the structural elucidation of the complex heparanome at the disaccharide or oligosaccharide level using liquid chromatography, nuclear magnetic resonance spectroscopy, and mass spectrometry. This review also outlines the utility of isotopes in determining the substrate specificity of biosynthetic enzymes that eventually dictate the emergence of biologically active oligosaccharides.

  15. Applications of Isotopes in Advancing Structural & Functional Heparanomics

    PubMed Central

    Tran, Vy M.; Nu Nguyen, Thao Kim; Raman, Karthik; Kuberan, Balagurunathan

    2011-01-01

    Heparanomics is the study of all the biologically active oligosaccharide domain structures in the entire heparanome and the nature of interactions among these domains and their protein ligands. Structural elucidation of heparan sulfate and heparin oligosaccharides is a major obstacle in advancing structure-function relationships and the study of heparanomics. There are several factors that exacerbate challenges involved in the structural elucidation of heparin and heparan sulfate. Therefore, there is a great interest in developing novel strategies and analytical tools to overcome the barriers in decoding the enigmatic heparanome. This review article focuses on the applications of isotopes, both radioisotopes and stable isotopes, in the structural elucidation of the complex heparanome at the disaccharide or oligosaccharide level using liquid chromatography, nuclear magnetic resonance spectroscopy and mass spectrometry. This review article also outlines the utility of isotopes in determining the substrate specificity of biosynthetic enzymes that eventually dictate the emergence of biologically active oligosaccharides. PMID:20838780

  16. Isotopic Bias and Uncertainty for Burnup Credit Applications

    SciTech Connect

    J.M. Scaglione

    2002-08-19

    The application of burnup credit requires calculating the isotopic inventory of the irradiated fuel. The depletion calculation simulates the burnup of the fuel under reactor operating conditions. The result of the depletion analysis is the predicted isotopic composition, which is ultimately input to a criticality analysis to determine the system multiplication factor (k{sub eff}). This paper demonstrates an approach for calculating the isotopic bias and uncertainty in k{sub eff} for commercial spent nuclear fuel burnup credit. This paper covers 74 different radiochemical assayed spent fuel samples from 22 different fuel assemblies that were irradiated in eight different pressurized water reactors (PWRs). The samples evaluated span an enrichment range of 2.556 wt% U-235 through 4.67 wt% U-235, and burnups from 6.92 GWd/MTU through 55.7 GWd/MTU.

  17. Biomedical research applications of electromagnetically separated enriched stable isotopes

    NASA Astrophysics Data System (ADS)

    Lambrecht, R. M.

    The current and projected annual requirements through 1985 for stable isotopes enriched by electromagnetic separation methods were reviewed for applications in various types of biomedical research: (1) medical radiosiotope production, labeled compounds, and potential radio-pharmaceuticals; (2) nutrition, food science, and pharmacology: (3) metallobiochemistry and environmental toxicology; (4) nuclear magnetic resonance, electron paramagnetic resonance, and moessbauer spectroscopy in biochemical, biophysical, and biomedical research; and (5) miscellaneous advances in radioactive and nonradioactive tracer technology. Radioisotopes available from commercial sources or routinely used in clinical nuclear medicine were excluded. Current requirements for enriched stable isotopes in biomedical research are not being satisfied. Severe shortages exist for Mg 26, Ca 43, Zn 70, Se 76, Se 77, Se 78, Pd 102, Cd 111, Cd 113, and Os 190. Many interesting and potentially important investigations in biomedical research require small quantities of specific elements at high isotopic enrichments.

  18. A Snapshot Imaging Spectropolarimeter

    DTIC Science & Technology

    2001-08-01

    Distribution UnliuLt:ýJ Abstract A revolutionary technique for snapshot imaging spectropolarimetry has been developed because of the recent availability...of large focal plane arrays and fast computers. The technique involves the combination of spectropolarimetry with computed tomography imaging...operate through the fusion of two techniques: channeled spectropolarimetry " 2 and computed tomography imaging spectrometry. Accordingly, it is

  19. Snapshot polarimeter fundus camera.

    PubMed

    DeHoog, Edward; Luo, Haitao; Oka, Kazuhiko; Dereniak, Eustace; Schwiegerling, James

    2009-03-20

    A snapshot imaging polarimeter utilizing Savart plates is integrated into a fundus camera for retinal imaging. Acquired retinal images can be processed to reconstruct Stokes vector images, giving insight into the polarization properties of the retina. Results for images from a normal healthy retina and retinas with pathology are examined and compared.

  20. Mediterranean Outflow and surface water variability off southern Portugal during the early Pleistocene: A snapshot at Marine Isotope Stages 29 to 34 (1020-1135 ka)

    NASA Astrophysics Data System (ADS)

    Voelker, Antje H. L.; Salgueiro, Emilia; Rodrigues, Teresa; Jimenez-Espejo, Francisco J.; Bahr, André; Alberto, Ana; Loureiro, Isabel; Padilha, Maria; Rebotim, Andreia; Röhl, Ursula

    2015-10-01

    Centennial-to-millennial scale records from IODP Site U1387, drilled during IODP Expedition 339 into the Faro Drift at 558 m water depth, now allow evaluating the climatic history of the upper core of the Mediterranean Outflow (MOW) and of the surface waters in the northern Gulf of Cadiz during the early Pleistocene. This study focuses on the period from Marine Isotope Stages (MIS) 29 to 34, i.e. the interval surrounding extreme interglacial MIS 31. Conditions in the upper MOW reflect obliquity, precession and millennial-scale variations. The benthic δ18O signal follows obliquity with the exception of an additional, smaller δ18O peak that marks the MIS 32/31 transition. Insolation maxima (precession minima) led to poor ventilation and a sluggish upper MOW core, whereas insolation minima were associated with enhanced ventilation and often also increased bottom current velocity. Millennial-scale periods of colder sea-surface temperatures (SST) were associated with short-term maxima in flow velocity and better ventilation, reminiscent of conditions known from MIS 3. A prominent contourite layer, coinciding with insolation cycle 100, was formed during MIS 31 and represents one of the few contourites developing within an interglacial period. MIS 31 surface water conditions were characterized by an extended period (1065-1091 ka) of warm SST, but SST were not much warmer than during MIS 33. Interglacial to glacial transitions experienced 2 to 3 stadial/interstadial cycles, just like their mid-to-late Pleistocene counterparts. Glacial MIS 30 and 32 recorded periods of extremely cold (< 12 °C) SST that in their climatic impact were comparable with the Heinrich events of the mid and late Pleistocene. Glacial MIS 34, on the other hand, was a relative warm glacial period off southern Portugal. Overall, surface water and MOW conditions at Site U1387 show a strong congruence with Mediterranean climate, whereas millennial-scale variations are closely linked to North Atlantic

  1. Robust snapshot interferometric spectropolarimetry.

    PubMed

    Kim, Daesuk; Seo, Yoonho; Yoon, Yonghee; Dembele, Vamara; Yoon, Jae Woong; Lee, Kyu Jin; Magnusson, Robert

    2016-05-15

    This Letter describes a Stokes vector measurement method based on a snapshot interferometric common-path spectropolarimeter. The proposed scheme, which employs an interferometric polarization-modulation module, can extract the spectral polarimetric parameters Ψ(k) and Δ(k) of a transmissive anisotropic object by which an accurate Stokes vector can be calculated in the spectral domain. It is inherently strongly robust to the object 3D pose variation, since it is designed distinctly so that the measured object can be placed outside of the interferometric module. Experiments are conducted to verify the feasibility of the proposed system. The proposed snapshot scheme enables us to extract the spectral Stokes vector of a transmissive anisotropic object within tens of msec with high accuracy.

  2. Isotope powered stirling generator for terrestrial applications

    NASA Astrophysics Data System (ADS)

    Tingey, Garth L.; Sorensen, Gerald C.; Ross, Brad A.

    1995-01-01

    An electric power supply, small enough to be man-portable, is being developed for remote, terrestrial applications. This system is designed for an operating lifetime of five years without maintenance or refueling. A small Radioisotope Stirling Generator (RSG) has been developed. The energy source of the generator is a 60 watt plutonium-238 fuel clad used in the General Purpose Heat Sources (GPHS) developed for space applications. A free piston Stirling ENgine drives a linear alternator to convert the heat to power. The system weighs about 7.5 kg and produces 11 watts AC power with a conversion efficiency of 18.5%. Two engine models have been designed, fabricated, and tested to data: (a) a development model instrumented to confirm and test parameters, and (b) an electrically heated model with an electrical heater equipped power input leads. Critical components have been tested for 10,000 to 20,000 hours. One complete generator has been operating for over 11,000 hours. Radioisotope heated prototypes are expected to be fabricated and tested in late 1995.

  3. Snapshot-Imaging Spectropolarimeter

    DTIC Science & Technology

    2005-11-17

    this backprojection+filtering is the process that the pseudoinverse matrix represents for this system. 3. CHANNELLED SPECTROPOLARIMETRY (CHSP...channel shown in Fig. 9.8 4. SNAPSHOT IMAGING SPECTROPOLARIMETRY (CTICS) By combining the techniques of CTIS with CHSP, we can construct an instrument... spectropolarimetry . PhD thesis, University of Arizona, Tucson, Arizona, 2002. 9. D. H. Goldstein, D. B. Chenault, W. G. Egan, and M. J. Duggin, eds., Polarization Analysis, Measurement, and Remote Sensing IV, Proc. SPIE 4481, 2001. 20

  4. Applications of nuclear and isotopic techniques in Indonesia

    SciTech Connect

    Hilmy, N.; Hendranto, K.

    1994-12-31

    Applications of Nuclear and Isotopic Techniques have been developed by the National Atomic Energy Agency (BATAN) since early 1970 in Indonesia. The scope of these applications covers various fields such as agriculture, hydrology, sedimentology and industry. Some applications of tracer techniques in industry which have been done such as measurement of homogeneity of mixing process in fertiliser and paper factory, residence time distribution in gold processing plant, mercury inventory in caustic soda plant, enhanced oil recovery in oil production wells, leakage investigation in dust chamber of fertiliser plant and blockage of pipeline, are presented in this paper. In the field of NDT by radiographic technique, BATAN regularly conducts training courses and also issues licences for Level I and II. Some applications of nuclear techniques in agriculture such as mutation breeding, animal production and animal health have shown the potential of radiation in creating variability as a basis for varietal improvements in several food crop species, the potential of using isotopes as tracers in the studies on metabolism, particularly in relation to the efficiency of rumen fermentative digestion and biological evaluation of locally available feedstuffs from agricultural and agro-industrial byproducts. So far, four varieties of nice, two varieties of soybean, and one variety of mungbean have been officially approved for release, and one formulation of feed supplement utilizing locally available agricultural and agro-industrial byproducts has been established and used for cattle and goats. In animal health, a radiovaccine against coccidiosis in poultry has been produced and used routinely.

  5. Stable isotope-resolved metabolomics and applications for drug development

    PubMed Central

    Fan, Teresa W-M.; Lorkiewicz, Pawel; Sellers, Katherine; Moseley, Hunter N.B.; Higashi, Richard M.; Lane, Andrew N.

    2012-01-01

    Advances in analytical methodologies, principally nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS), during the last decade have made large-scale analysis of the human metabolome a reality. This is leading to the reawakening of the importance of metabolism in human diseases, particularly cancer. The metabolome is the functional readout of the genome, functional genome, and proteome; it is also an integral partner in molecular regulations for homeostasis. The interrogation of the metabolome, or metabolomics, is now being applied to numerous diseases, largely by metabolite profiling for biomarker discovery, but also in pharmacology and therapeutics. Recent advances in stable isotope tracer-based metabolomic approaches enable unambiguous tracking of individual atoms through compartmentalized metabolic networks directly in human subjects, which promises to decipher the complexity of the human metabolome at an unprecedented pace. This knowledge will revolutionize our understanding of complex human diseases, clinical diagnostics, as well as individualized therapeutics and drug response. In this review, we focus on the use of stable isotope tracers with metabolomics technologies for understanding metabolic network dynamics in both model systems and in clinical applications. Atom-resolved isotope tracing via the two major analytical platforms, NMR and MS, has the power to determine novel metabolic reprogramming in diseases, discover new drug targets, and facilitates ADME studies. We also illustrate new metabolic tracer-based imaging technologies, which enable direct visualization of metabolic processes in vivo. We further outline current practices and future requirements for biochemoinformatics development, which is an integral part of translating stable isotope-resolved metabolomics into clinical reality. PMID:22212615

  6. Applications of C and N stable isotopes to ecological and environmental studies in seagrass ecosystems.

    PubMed

    Lepoint, Gilles; Dauby, Patrick; Gobert, Sylvie

    2004-12-01

    Stable isotopes of carbon and nitrogen are increasingly used in marine ecosystems, for ecological and environmental studies. Here, we examine some applications of stable isotopes as ecological integrators or tracers in seagrass ecosystem studies. We focus on both the use of natural isotope abundance as food web integrators or environmental tracers and on the use of stable isotopes as experimental tools. As ecosystem integrators, stable isotopes have helped to elucidate the general structure of trophic webs in temperate, Mediterranean and tropical seagrass ecosystems. As environmental tracers, stable isotopes have proven their utility in sewage impact measuring and mapping. However, to make such environmental studies more comprehensible, future works on understanding of basic reasons for variations of N and C stable isotopes in seagrasses should be encouraged. At least, as experimental tracers, stable isotopes allow the study of many aspects of N and C cycles at the scale of a plant or at the scale of the seagrass ecosystem.

  7. Introduction to chemistry and applications in nature of mass independent isotope effects special feature.

    PubMed

    Thiemens, Mark H

    2013-10-29

    Stable isotope ratio variations are regulated by physical and chemical laws. These rules depend on a relation with mass differences between isotopes. New classes of isotope variation effects that deviate from mass dependent laws, termed mass independent isotope effects, were discovered in 1983 and have a wide range of applications in basic chemistry and nature. In this special edition, new applications of these effects to physical chemistry, solar system origin models, terrestrial atmospheric and biogenic evolution, polar paleo climatology, snowball earth geology, and present day atmospheric sciences are presented.

  8. Introduction to Chemistry and Applications in Nature of Mass Independent Isotope Effects Special Feature

    PubMed Central

    Thiemens, Mark H.

    2013-01-01

    Stable isotope ratio variations are regulated by physical and chemical laws. These rules depend on a relation with mass differences between isotopes. New classes of isotope variation effects that deviate from mass dependent laws, termed mass independent isotope effects, were discovered in 1983 and have a wide range of applications in basic chemistry and nature. In this special edition, new applications of these effects to physical chemistry, solar system origin models, terrestrial atmospheric and biogenic evolution, polar paleo climatology, snowball earth geology, and present day atmospheric sciences are presented. PMID:24167299

  9. SNAPSHOT: A MODERN, SUSTAINABLE HOLDUP MEASUREMENT SYSTEM

    SciTech Connect

    Rowe, Nathan C; Younkin, James R; Smith, Steven E; Chapman, Jeffrey Allen; Dunn, Michael E; Stewart, Scott L

    2016-01-01

    SNAPSHOT is a software platform designed to eventually replace Holdup Measurement System 4 (HMS 4), which is the current state-of-the-art for acquisition and analysis of nondestructive assay measurement data for in situ nuclear materials, holdup, in support of criticality safety and material control and accounting. HMS 4 is over 10 years old and is currently unsustainable due to hardware and software incompatibilities that have arisen from advances in detector electronics, primarily updates to multi-channel analyzers (MCAs), and both computer and handheld operating systems. SNAPSHOT is a complete redesign of HMS 4 that addresses the issue of compatibility with modern MCAs and operating systems and that is designed with a flexible architecture to support long-term sustainability. It also provides an updated and more user friendly interface and is being developed under an NQA 1 software quality assurance (SQA) program to facilitate site acceptance for safety-related applications. This paper provides an overview of the SNAPSHOT project including details of the software development process, the SQA program, and the architecture designed to support sustainability.

  10. Saturn's Infrared Temperature Snapshot

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Annotated Version

    Scientists have discovered a wave pattern, or oscillation, in Saturn's atmosphere only visible from Earth every 15 years. The pattern ripples back and forth like a wave within Saturn's upper atmosphere. In this region, temperatures switch from one altitude to the next in a candy cane-like, striped, hot-cold pattern.

    The temperature 'snapshot' shown in these two images captures two different phases of this wave oscillation: the temperature at Saturn's equator switches from hot to cold, and temperatures on either side of the equator switch from cold to hot every Saturn half-year.

    The image on the left was taken in 1997 and shows the temperature at the equator is colder than the temperature at 13 degrees south latitude. Conversely, the image on the right taken in 2006 shows the temperature at the equator is warmer.

    These images were taken with NASA's Infrared Telescope Facility in Mauna Kea, Hawaii.

  11. Isotopically Modified Molybdenum: Production for Application in Nuclear Energy

    NASA Astrophysics Data System (ADS)

    Smirnov, A. Yu.; Bonarev, A. K.; Sulaberidze, G. A.; Borisevich, V. D.; Kulikov, G. G.; Shmelev, A. N.

    The possibility to use the isotopically modified molybdenum as a constructive material for the fuel rods of light water and fast reactors is discussed. The calculations demonstrate that the isotopically modified molybdenum with an average neutron absorption cross-section comparable to that of zirconium can be obtained with the reasonable for practice cost by a cascade of gas centrifuges, specially designed for separation of non-uranium isotopes.

  12. Forensic applications of isotope ratio mass spectrometry--a review.

    PubMed

    Benson, Sarah; Lennard, Chris; Maynard, Philip; Roux, Claude

    2006-02-10

    The key role of a forensic scientist is to assist in determining whether a crime has been committed, and if so, assist in the identification of the offender. Many people hold the belief that a particular item can be conclusively linked to a specific person, place or object. Unfortunately, this is often not achievable in forensic science. In performing their role, scientists develop and test hypotheses. The significance of those hypotheses that cannot be rejected upon completion of all available examinations/analyses is then evaluated. Although one can generally identify the substances present using available techniques, it is generally not possible to distinguish one source of the same substance from another. In such circumstances, although a particular hypothesis cannot be rejected, it cannot be conclusively proven, i.e. the samples could still have originated from different sources. This limitation of not being able to distinguish between sources currently extends to the analysis of other forensic samples including, but not limited to, ignitable liquids, paints, adhesives, textile fibres, plastics, and illicit drugs. Stable isotope ratio mass spectrometry (IRMS) is an additional technique that can be utilised to test a given hypothesis. This technique shows the potential to be able to individualise a range of materials of forensic interest. This paper provides a brief description of the technique, followed by a review of the various applications of IRMS in different scientific fields. The focus of this summary is on forensic applications of IRMS, in particular the analysis of explosives, ignitable liquids and illicit drugs.

  13. Application of Molybdenum isotopes as proxy for weathering conditions

    NASA Astrophysics Data System (ADS)

    Siebert, C.; Pett-Ridge, J.; Burton, K.; Halliday, A. N.

    2008-12-01

    Molybdenum isotopes have become an important tracer for paleo-redox conditions in the oceans and paleo- oceans. Mo is also an essential enzyme co-factor in organisms and therefore important in studies of nitrogen fixation and reduction. With an increasing amount of data on the biogeochemical behavior of Mo in the oceans, it is now possible to better constrain the general behavior of Mo in the marine environment. However, the terrestrial geochemistry of Mo remains very poorly understood. For example, in contrast to earlier assumptions, recent measurements of river-waters (Archer & Vance(2008) Nature Geoscience, Vol. 1, P. 597; Pearce et al. (2008) Geology, Vol. 36, 3, P. 231) suggest that the Mo isotopic input into the oceans is more variable and more enriched in heavy isotopes then previously assumed. So far these variations do not easily correlate with the isotope composition of the source rocks in the catchment area of rivers. Therefore, fractionation during weathering and transport does indeed occur and it is essential to understand the processes controlling the Mo isotope composition of rivers, if one wants to utilize Mo isotopes as quantitative (paleo-)proxy for marine redox-conditions. The aim of this study is to investigate the biogeochemistry of molybdenum in weathering profiles. Results are promising and suggest that molybdenum isotopes may also become useful tracers for redox-conditions during weathering. Results show a clear correlation of Mo isotope compositions with rainfall gradients (i.e. redox conditions) in saprolites from Hawaii. Weathering profiles from Puerto Rico also imply a strong dependence of the Mo isotope composition on pH shifts within a weathering profile. More data are necessary to judge the influence of these processes on the overall Mo isotope composition of rivers and therefore the Mo input to the oceans. However, it becomes clear that the processes affecting Mo isotopes in the terrestrial environment might be complex and need to be

  14. The potential for application of ink stable isotope analysis in questioned document examination.

    PubMed

    Chesson, Lesley A; Tipple, Brett J; Barnette, Janet E; Cerling, Thure E; Ehleringer, James R

    2015-01-01

    We investigated a novel application of stable isotope abundance analysis of nitrogen (15N), carbon (13C), hydrogen (2H), and oxygen (18O) to characterize pen ink. We focused on both ballpoint and gel pen inks. We found that the isotope ratios of ink from pens purchased together in a package were similar and within-package stable isotope ratio variability was not significantly larger than the variability of isotope reference materials used during analysis. In contrast, the isotope ratios of ink from pens of the same brand purchased in three states of the continental USA were significantly different from each other and there was isotope ratio variation among pens of the same brand but different, unknown production periods. The stable isotope ratios of inked paper were statistically distinguishable using measured δ15N values. Paper inked with different gel pens was statistically distinguishable using measured δ2H values. The capacity of stable isotope ratios to differentiate among ballpoint inks as well as gel inks shows that stable isotope analysis may be a useful and quantifiable investigative technique for questioned document examination, although current sample size requirements limit its utility. Application of the technique in casework will require the development of micro-scale sampling and analysis methods. Copyright © 2014 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.

  15. Sulphur isotope applications in two Philippine geothermal systems

    SciTech Connect

    Bayon, F.E.B.

    1996-12-31

    A general and very preliminary study of sulphur isotope geochemistry is presented in this paper. Data from the Mt. Apo and Palinpinon geothermal fields are used to demonstrate the use of sulphur isotopes in geothermometry and correlation of sulphur species. Sulphur and oxygen isotope geothermometers applied to Mt. Apo data show very good agreement with temperatures estimated using other established geothermometers, as well as bore measured temperatures. This signifies that sulphur isotopes in S-species in fluids of the Mt. Apo hydrothermal system are in equilibrium at drilled depths. In Palinpinon, on the other hand, temperature estimates from fluid and mineral sulphur isotope geothermometry calculations do not agree with, and are commonly higher than, well measured temperatures and temperatures estimated from other geothermometers. Sulphur isotopes in the presently-exploited Palinpinon fluid are not in equilibrium, and sulphur isotope geothermometry may be reflective of isotopic equilibrium of the deeper portions of the hydrothermal system. Dissolved sulphate in both the Palinpinon and Mt. Apo geothermal fluids appear to originate from the disproportionation of magmatic SO{sub 2} at temperatures below 400{degrees}C. Hydrogen sulphide in well discharge fluids are dominantly directly derived from the magma, with a minor amount coming from SO{sub 2} disproportionation.

  16. Environmental and biomedical applications of natural metal stable isotope variations

    USGS Publications Warehouse

    Bullen, T.D.; Walczyk, T.

    2009-01-01

    etal stable isotopes are now being used to trace metal contaminants in the environment and as indicators of human systemic function where metals play a role. Stable isotope abundance variations provide information about metal sources and the processes affecting metals in complex natural systems, complementing information gained from surrogate tracers, such as metal abundance ratios or biochemical markers of metal metabolism. The science is still in its infancy, but the results of initial studies confirm that metal stable isotopes can provide a powerful tool for forensic and biomedical investigations.

  17. Application of the Extended Pairing Model to Heavy Isotopes

    SciTech Connect

    Gueorguiev, V G; Pan, F; Draayer, J P

    2004-09-28

    The binding energies of three isotopic chains ({sup 100-130}Sn, {sup 152-181}Yb, and {sup 181-202}Pb) are studied using the extended pairing model. By using the exact solvability of the model one determines the pairing strength G(A) that reproduces the experimental binding energies. For these isotopic chains, log (G(A)) has a smooth systematic behavior. In particular, G(A) for the Pb and Sn isotopes can be described by a two parameter expression that is inversely proportional to the dimensionality of the model space.

  18. American Youth: A Statistical Snapshot.

    ERIC Educational Resources Information Center

    Wetzel, James R.

    This document presents a statistics snapshot of young people, aged 15 to 24 years. It provides a broad overview of trends documenting the direction of changes in social behavior and economic circumstances. The projected decline in the total number of youth from 43 million in 1980 to 35 million in 1995 will affect marriage and childbearing…

  19. Mobility. Snapshot Report, Spring 2012

    ERIC Educational Resources Information Center

    National Student Clearinghouse, 2012

    2012-01-01

    This snapshot report presents information on student mobility for 2012. It offers data on the following: (1) Percentage of Students Completing Degrees at Four-Year Institutions Who Previously Enrolled at Two-Year Institutions; (2) Number of Years Between Degree Completion at Four-Year Institutions and Most Recent Enrollment at Two-Year…

  20. American Youth: A Statistical Snapshot.

    ERIC Educational Resources Information Center

    Wetzel, James R.

    This document presents a statistics snapshot of young people, aged 15 to 24 years. It provides a broad overview of trends documenting the direction of changes in social behavior and economic circumstances. The projected decline in the total number of youth from 43 million in 1980 to 35 million in 1995 will affect marriage and childbearing…

  1. Tunable Snapshot Spectrometer Feasibility Study

    DTIC Science & Technology

    2004-09-30

    tunable snapshot imaging spectrometer has been demonstrated. A liquid crystal spatial light modulator (LC SLM) has been integrated into a...integrate a liquid crystal spatial light modulator into a CTIS instrument and characterize its performance as a tunable CTIS disperser, and (2) to...Spectrometer Liquid Crystal Spatial Light Modulator Computer Generated Hologram 15. NUMBER OF PAGES 138

  2. Building Biographies: A Snapshot Approach.

    ERIC Educational Resources Information Center

    Zarnowski, Myra

    1986-01-01

    Proposes a method for building biographies with elementary students. Called the "snapshot approach," it encourages students to visualize memorable events in the life of the person being studied. Step one is gathering and studying biographical information, step two is selecting the material to use, and step three is arranging and interpreting the…

  3. Application of environmental isotopes to characterize landfill gases and leachate

    SciTech Connect

    Liu, C.L.; Hackley, K.C. ); Baker, J. . Environmental Labs.)

    1992-01-01

    Environmental isotopes have been used to help characterize landfill gases and leachate for the purpose of identifying leachate and/or gas contamination in surrounding monitoring wells. Carbon isotopes (C-13/C-12 and C-14), hydrogen isotopes (H-3 and H-2/H-1) and oxygen isotopes (O-18/O-16) were used to characterize methane, carbon dioxide and leachate produced from two municipal landfills in northeastern Illinois. The isotopic results from the landfill-derived gases and leachate are compared to isotopic compositions of groundwater and gases from nearby monitoring wells. C-14 activity of landfill CH[sub 4] is high compared to CH[sub 4] normally found in subsurface sediments. For this study C-14 activities of the landfill methane range from 129--140 PMC. The C-14 of the dissolved inorganic carbon (DIC) of the leachate samples also have relatively high activities, ranging from 126--141 PMC. The [delta]C-13 and [delta]D values for CH[sub 4] from the landfills fall within a range of values representative of microbial methane produced by acetate-fermentation. The [delta]C-13 of the CO[sub 2] and the DIC are very positive, ranging from 8--14[per thousand] for CO[sub 2] and 13--22[per thousand] for DIC. The [delta]O-18 values of the leachates are similar to current meteoric water values, however, two of the leachate samples are significantly enriched in deuterium by approximately 65[per thousand]. Tritium values of the leachate water are generally higher than expected. For one landfill the tritium activity ranges from 227--338 TU, for the second landfill the tritium activity is approximately 1,300 TU. Compared to tritium levels in normal groundwater, these higher tritium values in the leachates indicate that this isotope has the potential to be an effective tracer for detecting leachate migration.

  4. Ammonium transport and reaction in contaminated groundwater: Application of isotope tracers and isotope fractionation studies

    USGS Publications Warehouse

    Böhlke, J.K.; Smith, R.L.; Miller, D.N.

    2006-01-01

    Ammonium (NH4+) is a major constituent of many contaminated groundwaters, but its movement through aquifers is complex and poorly documented. In this study, processes affecting NH4+ movement in a treated wastewater plume were studied by a combination of techniques including large-scale monitoring of NH4+ distribution; isotopic analyses of coexisting aqueous NH4+, NO3-, N2, and sorbed NH 4+; and in situ natural gradient 15NH 4+ tracer tests with numerical simulations of 15NH4+, 15NO3-, and 15N2 breakthrough data. Combined results indicate that the main mass of NH4+ was moving downgradient at a rate about 0.25 times the groundwater velocity. Retardation factors and groundwater ages indicate that much of the NH4+ in the plume was recharged early in the history of the wastewater disposal. NO3- and excess N2 gas, which were related to each other by denitrification near the plume source, were moving downgradient more rapidly and were largely unrelated to coexisting NH 4+. The ??15N data indicate areas of the plume affected by nitrification (substantial isotope fractionation) and sorption (no isotope fractionation). There was no conclusive evidence for NH 4+-consuming reactions (nitrification or anammox) in the anoxic core of the plume. Nitrification occurred along the upper boundary of the plume but was limited by a low rate of transverse dispersive mixing of wastewater NH4+ and O2 from overlying uncontaminated groundwater. Without induced vertical mixing or displacement of plume water with oxic groundwater from upgradient sources, the main mass of NH4+ could reach a discharge area without substantial reaction long after the more mobile wastewater constituents are gone. Multiple approaches including in situ isotopic tracers and fractionation studies provided critical information about processes affecting NH4+ movement and N speciation.

  5. Iron and nickel isotope fractionation by diffusion, with applications to iron meteorites

    NASA Astrophysics Data System (ADS)

    Watson, Heather C.; Richter, Frank; Liu, Ankun; Huss, Gary R.

    2016-10-01

    Mass-dependent, kinetic fractionation of isotopes through processes such as diffusion can result in measurable isotopic signatures. When these signatures are retained in geologic materials, they can be used to help interpret their thermal histories. The mass dependence of the diffusion coefficient of isotopes 1 and 2 can be written as (D1 /D2) =(m2 /m1) β, where D1 and D2 are the diffusion coefficients of m1 and m2 respectively, and β is an empirical coefficient that relates the two ratios. Experiments have been performed to measure β in the Fe-Ni alloy system. Diffusion couple experiments between pure Fe and Ni metals were run in a piston cylinder at 1300-1400 °C and 1 GPa. Concentration and isotopic profiles were measured by electron microprobe and ion microprobe respectively. We find that a single β coefficient of β = 0.32 ± 0.04 can describe the isotopic effect in all experiments. This result is comparable to the isotope effect determined in many other similar alloy systems. The new β coefficient is used in a model of the isotopic profiles to be expected during the Widmanstätten pattern formation in iron meteorites. The results are consistent with previous estimates of the cooling rate of the iron meteorite Toluca. The application of isotopic constraints based on these results in addition to conventional cooling rate models could provide a more robust picture of the thermal history of these early planetary bodies.

  6. Application of helium isotopes to studies of ocean circulation

    NASA Astrophysics Data System (ADS)

    Schlosser, P.; Newton, R.; Winckler, G.; Lupton, J.; Jenkins, W.; Top, Z.; Roether, W.; Jean-Baptiste, P.

    2004-12-01

    Since the discovery of excess He-3 in the ocean by Clarke and Craig in the 1960's helium isotopes have been used in local, regional and global studies of circulation patterns and water mass transformation in the world ocean. From initial pilot studies through systematic exploration of these tracers during the GEOSECS (Geochemical Ocean Sections) program to the recent global survey as part of the WOCE (World Ocean Circulation Experiment) hydrographic program (WHP) we obtained more detailed information on the distribution of helium isotopes, as well as their sources and sinks in the ocean. This information can now be applied to construct global fields of helium isotopes and to extract unique information on the circulation patterns at different depth levels in the ocean, as well as on local and regional processes such as ventilation of water masses in deep water formation regions. Additionally, the data sets are now sufficiently large to be useful for validation of Ocean General Circulation Models (OGCM's). In this contribution we present examples of global helium isotope fields constructed from major programs such as GEOCECS, TTO (Transient Tracers in the Ocean), SAVE (South Atlantic Ventilation Experiment) and WOCE, as well as from individual ocean sections. We use the data to delineate circulation patterns in the major ocean basins at several depth levels, especially mid-depth waters. Additionally, we outline the use of helium isotopes in studies of ocean ventilation. Finally, we compare observed and simulated helium isotope fields to highlight OGCM capabilities and deficiencies to reproduce internal He-3 excesses in the ocean and the related ventilation processes.

  7. Lead (Pb) isotopic fingerprinting and its applications in lead pollution studies in China: a review.

    PubMed

    Cheng, Hefa; Hu, Yuanan

    2010-05-01

    As the most widely scattered toxic metal in the world, the sources of lead (Pb) observed in contamination investigation are often difficult to identify. This review presents an overview of the principles, analysis, and applications of Pb isotopic fingerprinting in tracing the origins and transport pathways of Pb in the environment. It also summarizes the history and current status of lead pollution in China, and illustrates the power of Pb isotopic fingerprinting with examples of its recent applications in investigating the effectiveness of leaded gasoline phase-out on atmospheric lead pollution, and the sources of Pb found in various environmental media (plants, sediments, and aquatic organisms) in China. The limitations of Pb isotopic fingerprinting technique are discussed and a perspective on its development is also presented. Further methodological developments and more widespread instrument availability are expected to make isotopic fingerprinting one of the key tools in lead pollution investigation.

  8. Unique Features and Spacecraft Applications of Dynamic Isotope Power Systems

    SciTech Connect

    Raab, B.

    1982-01-01

    The dynamic isotope power system represents the most recent attempt to develop a heat-engine generator for space electric power. A major objective in this most recent effort was to increase the power and to reduce the cost of nuclear space power systems to the point where the unique features of this power source could be brought to bear for Earth-orbit missions which could benefit therefrom. This objective was largely achieved; both weight and cost of the dynamic isotope systems are comparable to solar power systems. The dynamic isotope power system, designed for spacecraft requiring prime power in the 500-2000 W range, has been successfully built and ground tested. A number of studies, summarized herein, have demonstrated the advantages of using such a power system instead of the conventional solar system for a variety of Earth-orbit missions. These advantages stem from the unique nature of the dynamic isotope system, different in kind from solar power systems. As a result, in many cases, the spacecraft design can be significantly simplified and more closely harmonized with mission requirements. This overall advantage can be crucial in missions which have stringent pointing, stability, viewing, and/or positioning requirements.

  9. SnapShot: Interferon Signaling.

    PubMed

    Chow, Kwan T; Gale, Michael

    2015-12-17

    Interferons (IFNs) are crucial cytokines of antimicrobial, antitumor, and immunomodulatory activity. The three types of IFN (I, II, and III) are classified by their receptor specificity and sequence homology. IFNs are produced and secreted by cells in response to specific stimuli. Here, we review the subsequent IFN signaling events occurring through unique receptors leading to regulation of gene expression for modulation of innate and adaptive immunity. To view this SnapShot, open or download the PDF.

  10. Transient competitive complexation in biological kinetic isotope fractionation explains non-steady isotopic effects: Theory and application to denitrification in soils

    SciTech Connect

    Maggi, F.M.; Riley, W.J.

    2009-06-01

    The theoretical formulation of biological kinetic reactions in isotopic applications often assume first-order or Michaelis-Menten-Monod kinetics under the quasi-steady-state assumption to simplify the system kinetics. However, isotopic e ects have the same order of magnitude as the potential error introduced by these simpli cations. Both formulations lead to a constant fractionation factor which may yield incorrect estimations of the isotopic effect and a misleading interpretation of the isotopic signature of a reaction. We have analyzed the isotopic signature of denitri cation in biogeochemical soil systems by Menyailo and Hungate [2006], where high {sup 15}N{sub 2}O enrichment during N{sub 2}O production and inverse isotope fractionation during N{sub 2}O consumption could not be explained with first-order kinetics and the Rayleigh equation, or with the quasi-steady-state Michaelis-Menten-Monod kinetics. When the quasi-steady-state assumption was relaxed, transient Michaelis-Menten-Monod kinetics accurately reproduced the observations and aided in interpretation of experimental isotopic signatures. These results may imply a substantial revision in using the Rayleigh equation for interpretation of isotopic signatures and in modeling biological kinetic isotope fractionation with first-order kinetics or quasi-steady-state Michaelis-Menten-Monod kinetics.

  11. Application of dual carbon-bromine isotope analysis for investigating abiotic transformations of tribromoneopentyl alcohol (TBNPA).

    PubMed

    Kozell, Anna; Yecheskel, Yinon; Balaban, Noa; Dror, Ishai; Halicz, Ludwik; Ronen, Zeev; Gelman, Faina

    2015-04-07

    Many of polybrominated organic compounds, used as flame retardant additives, belong to the group of persistent organic pollutants. Compound-specific isotope analysis is one of the potential analytical tools for investigating their fate in the environment. However, the isotope effects associated with transformations of brominated organic compounds are still poorly explored. In the present study, we investigated carbon and bromine isotope fractionation during degradation of tribromoneopentyl alcohol (TBNPA), one of the widely used flame retardant additives, in three different chemical processes: transformation in aqueous alkaline solution (pH 8); reductive dehalogenation by zero-valent iron nanoparticles (nZVI) in anoxic conditions; oxidative degradation by H2O2 in the presence of CuO nanoparticles (nCuO). Two-dimensional carbon-bromine isotope plots (δ(13)C/Δ(81)Br) for each reaction gave different process-dependent isotope slopes (Λ(C/Br)): 25.2 ± 2.5 for alkaline hydrolysis (pH 8); 3.8 ± 0.5 for debromination in the presence of nZVI in anoxic conditions; ∞ in the case of catalytic oxidation by H2O2 with nCuO. The obtained isotope effects for both elements were generally in agreement with the values expected for the suggested reaction mechanisms. The results of the present study support further applications of dual carbon-bromine isotope analysis as a tool for identification of reaction pathway during transformations of brominated organic compounds in the environment.

  12. High-precision gamma-ray spectroscopy for enhancing production and application of medical isotopes

    NASA Astrophysics Data System (ADS)

    McCutchan, E. A.; Sonzogni, A. A.; Smith, S. V.; Muench, L.; Nino, M.; Greene, J. P.; Carpenter, M. P.; Zhu, S.; Chillery, T.; Chowdhury, P.; Harding, R.; Lister, C. J.

    2015-10-01

    Nuclear medicine is a field which requires precise decay data for use in planning radionuclide production and in imaging and therapeutic applications. To address deficiencies in decay data, sources of medical isotopes were produced and purified at the Brookhaven Linear Isotope Producer (BLIP) then shipped to Argonne National Laboratory where high-precision, gamma-ray measurements were performed using Gammasphere. New decay schemes for a number of PET isotopes and the impact on dose calculations will be presented. To investigate the production of next-generation theranostic or radiotherapeutic isotopes, cross section measurements with high energy protons have also been explored at BLIP. The 100-200 MeV proton energy regime is relatively unexplored for isotope production, thus offering high discovery potential but at the same time a challenging analysis due to the large number of open channels at these energies. Results of cross sections deduced from Compton-suppressed, coincidence gamma-ray spectroscopy performed at Lowell will be presented, focusing on the production of platinum isotopes by irradiating natural platinum foils with 100 to 200 MeV protons. DOE Isotope Program is acknowledged for funding ST5001030. Work supported by the US DOE under Grant DE-FG02-94ER40848 and Contracts DE-AC02-98CH10946 and DE-AC02-06CH11357.

  13. Application of Tunable Diode Laser Spectrometry for Isotopic Analysis

    NASA Technical Reports Server (NTRS)

    Sauke, T. B.; Becker, J. F.; Loewenstein, M.; Gutierrez, T. D.; Bratton, C. G.

    1994-01-01

    Lead-salt tunable diode lasers are now commercially available with operating temperatures above 77 K and excellent single-mode characteristics which make them very useful for spectroscopy in the mid-IR spectral range. Using these lasers for absorption measurements in the 4.3 micrometer spectral region we have made accurate measurements of isotopic abundances in CO2. The method involves assembly language controlled data acquisition of spectra of selected adjacent isotopic rotational lines, an etalon spectral frequency calibration technique, the fitting of multiple Voigt profiles to the data, and the ratioing of absorbances from simultaneously acquired sample and reference data scans. The accuracy achieved is better than 0.4% for the C-13/C-12 ratio and 1% for the O-18/O-16 ratio. Higher accuracy is expected from improvements now being implemented.

  14. Reactor Fuel Isotopics and Code Validation for Nuclear Applications

    SciTech Connect

    Francis, Matthew W.; Weber, Charles F.; Pigni, Marco T.; Gauld, Ian C.

    2015-02-01

    Experimentally measured isotopic concentrations of well characterized spent nuclear fuel (SNF) samples have been collected and analyzed by previous researchers. These sets of experimental data have been used extensively to validate the accuracy of depletion code predictions for given sets of burnups, initial enrichments, and varying power histories for different reactor types. The purpose of this report is to present the diversity of data in a concise manner and summarize the current accuracy of depletion modeling. All calculations performed for this report were done using the Oak Ridge Isotope GENeration (ORIGEN) code, an internationally used irradiation and decay code solver within the SCALE comprehensive modeling and simulation code. The diversity of data given in this report includes key actinides, stable fission products, and radioactive fission products. In general, when using the current ENDF/B-VII.0 nuclear data libraries in SCALE, the major actinides are predicted to within 5% of the measured values. Large improvements were seen for several of the curium isotopes when using improved cross section data found in evaluated nuclear data file ENDF/B-VII.0 as compared to ENDF/B-V-based results. The impact of the flux spectrum on the plutonium isotope concentrations as a function of burnup was also shown. The general accuracy noted for the actinide samples for reactor types with burnups greater than 5,000 MWd/MTU was not observed for the low-burnup Hanford B samples. More work is needed in understanding these large discrepancies. The stable neodymium and samarium isotopes were predicted to within a few percent of the measured values. Large improvements were seen in prediction for a few of the samarium isotopes when using the ENDF/B-VII.0 libraries compared to results obtained with ENDF/B-V libraries. Very accurate predictions were obtained for 133Cs and 153Eu. However, the predicted values for the stable ruthenium and rhodium isotopes varied

  15. Non-standard isotope production and applications at Washington University

    NASA Astrophysics Data System (ADS)

    McCarthy, Timothy J.; McCarthy, Deborah W.; Laforest, Richard; Bigott, Heather M.; Wüst, Frank; Reichert, David E.; Lewis, Michael R.; Welch, Michael J.

    2001-07-01

    The positron emitting radionuclides, oxygen-15, nitrogen-13, carbon-11, and fluorine-18 have been produced at Washington University for many years utilizing two biomedical cyclotrons; a Cyclotron Corporation CS15 and a Japan Steel Works 16/8 cyclotron. In recent years we have become interested in the production of non-standard PET isotopes. We were initially interested in copper-64 production using the 64Ni(p,n)64Cu nuclear reaction, but now apply this technique to other positron emitting copper isotopes, copper-60 and copper-61. Copper-64 is being produced routinely and made available to other institutions. In 1999 over ten Curies of copper-64 were produced, making copper available to thirteen institutions, as well as research groups at Washington University. We are currently developing methods for the routine productions of other PET radioisotopes of interest, these include; bromine-76, bromine-77, iodine-124, gallium-66, and technetium-94m.

  16. Application of Stable Isotope-Assisted Metabolomics for Cell Metabolism Studies

    PubMed Central

    You, Le; Zhang, Baichen; Tang, Yinjie J.

    2014-01-01

    The applications of stable isotopes in metabolomics have facilitated the study of cell metabolisms. Stable isotope-assisted metabolomics requires: (1) properly designed tracer experiments; (2) stringent sampling and quenching protocols to minimize isotopic alternations; (3) efficient metabolite separations; (4) high resolution mass spectrometry to resolve overlapping peaks and background noises; and (5) data analysis methods and databases to decipher isotopic clusters over a broad m/z range (mass-to-charge ratio). This paper overviews mass spectrometry based techniques for precise determination of metabolites and their isotopologues. It also discusses applications of isotopic approaches to track substrate utilization, identify unknown metabolites and their chemical formulas, measure metabolite concentrations, determine putative metabolic pathways, and investigate microbial community populations and their carbon assimilation patterns. In addition, 13C-metabolite fingerprinting and metabolic models can be integrated to quantify carbon fluxes (enzyme reaction rates). The fluxome, in combination with other “omics” analyses, may give systems-level insights into regulatory mechanisms underlying gene functions. More importantly, 13C-tracer experiments significantly improve the potential of low-resolution gas chromatography-mass spectrometry (GC-MS) for broad-scope metabolism studies. We foresee the isotope-assisted metabolomics to be an indispensable tool in industrial biotechnology, environmental microbiology, and medical research. PMID:24957020

  17. Application of laser Raman spectroscopy to isotopic methanes analysis in fusion fuel gas processing systems

    SciTech Connect

    Uda, T. ); Okuno, K.; Naruse, Y. )

    1992-03-01

    This paper reports that to study application o laser Raman spectroscopy for fusion fuel gas analysis by an in situ method, methane (CH{sub 4}) and tritium (T{sub 2}) mixed gases were measured. In the mixed gases, hydrogen isotope exchange reactions were induced by beta decay, and various isotopic hydrogens and methanes were produced. Spectral peaks of {nu}{sub 1} and {nu}{sub 3} bands were detected individually for CH{sub 4} and four tritiated methanes. The {nu}{sub 1} bands between 1700-1900 cm{sup {minus}1} were selected as suitable ones for quantitative analysis. After mixing T{sub 2} and CH{sub 4} gases, while large amounts of tritiated methanes were produced as time lapsed, the equilibrium state was not reached by the time 1000 h had passed. It was presumed that the isotope exchange reactions were very slow compared to mixed gases of just hydrogen isotopes.

  18. Validation of a method for prediction of isotopic concentrations in burnup credit applications

    SciTech Connect

    DeHart, M.D.; Hermann, O.W.; Parks, C.V.

    1995-09-01

    Unlike fresh fuel assumptions typically employed in the criticality safety analysis of spent fuel configurations, burnup credit applications rely on depletion and decay calculations to predict the isotopic composition of spent fuel. These isotopics are used in subsequent criticality calculations to assess the reduced worth of the spent fuel. To validate the codes and data used in depletion approaches, experimental measurements are compared with numerical predictions for relevant spent fuel samples. This paper describes a set of experimentally characterized pressurized-water-reactor (PWR) fuel samples and provides a comparison to results of SCALE-4 depletion calculations. An approach to determine biases and uncertainties between calculated and measured isotopic concentrations is discussed, together with a method to statistically combine these terms to obtain a conservative estimate of spent fuel isotopic concentrations.

  19. Snapshot depth sensitive Raman spectroscopy in layered tissues.

    PubMed

    Liu, Wei; Ong, Yi Hong; Yu, Xiao Jun; Ju, Jian; Perlaki, Clint Michael; Liu, Lin Bo; Liu, Quan

    2016-12-12

    Depth sensitive Raman spectroscopy has been shown effective in the detection of depth dependent Raman spectra in layered tissues. However, the current techniques for depth sensitive Raman measurements based on fiber-optic probes suffer from poor depth resolution and significant variation in probe-sample contact. In contrast, those lens based techniques either require the change in objective-sample distance or suffer from slow spectral acquisition. We report a snapshot depth-sensitive Raman technique based on an axicon lens and a ring-to-line fiber assembly to simultaneously acquire Raman signals emitted from five different depths in the non-contact manner without moving any component. A numerical tool was developed to simulate ray tracing and optimize the snapshot depth sensitive setup to achieve the tradeoff between signal collection efficiency and depth resolution for Raman measurements in the skin. Moreover, the snapshot system was demonstrated to be able to acquire depth sensitive Raman spectra from not only transparent and turbid skin phantoms but also from ex vivo pork tissues and in vivo human thumbnails when the excitation laser power was limited to the maximum permissible exposure for human skin. The results suggest the great potential of snapshot depth sensitive Raman spectroscopy in the characterization of the skin and other layered tissues in the clinical setting or other similar applications such as quality monitoring of tablets and capsules in pharmaceutical industry requiring the rapid measurement of depth dependent Raman spectra.

  20. High Precision Isotope Analyses Using Multi-Collector SIMS: Applications to Earth and Planetary Science.

    NASA Astrophysics Data System (ADS)

    Kita, N. T.; Ushikubo, T.; Valley, J. W.

    2008-05-01

    The CAMECA IMS-1280 large radius, multicollector ion microprobe at the Wisc-SIMS National Facility is capable of high accuracy and precision for in situ analysis of isotope ratios. With improved hardware stability and software capability, high precision isotope analyses are routinely performed, typically 5 min per spot. We have developed analytical protocols for stable isotope analyses of oxygen, carbon, Mg, Si and Sulfur using multi-collector Faraday Cups (MCFC) and achieved precision of 0.1-0.2 ‰ (1SD) from a typically 10μm spot analyses. A number of isotopically homogeneous mineral standards have been prepared and calibrated in order to certify the accuracy of analyses in the same level. When spatial resolution is critical, spot size is reduced down to sub- μm for δ 18O to obtain better than 0.5‰ (1SD) precision by using electron multiplier (EM) on multi-collection system. Multi-collection EM analysis is also applied at 10 ppm level to Li isotope ratios in zircon with precision better than 2‰ (1SD). A few applications will be presented. (1) Oxygen three isotope analyses of chondrules in ordinary chondrites revealed both mass dependent and mass independent oxygen isotope fractionations among chondrules as well as within individual chondrules. The results give constraints on the process of chondrule formation and origin of isotope reservoirs in the early solar system. (2) High precision 26Al-26Mg (half life of 0.73 Ma) chronology is applied to zoned melilite and anorthite from Ca, Al-rich inclusions (CAI) in Leoville meteorite, and a well-defined internal isochron is obtained. The results indicate the Al- Mg system was remained closed within 40ky of the crystallization of melilite and anorthite in this CAI. (3) Sub- μm spot analyses of δ18O in isotopically zoned zircon from high-grade metamorphism reveals a diffusion profile of ~6‰ over 2μm, indicating slow diffusion of oxygen in zircon. This result also implies that old Archean detrital zircons (> 4

  1. Oxygen Isotope in Phosphate an Indicator of Phosphorous Cycling in the Ocean - Controls, and Applications

    NASA Astrophysics Data System (ADS)

    Paytan, A.; Roberts, K.; Defforey, D.; McLaughlin, K.; Lomas, M. W.; Church, M. J.; Mackey, K. R.

    2012-12-01

    In order to better constrain the parameters affecting oxygen isotope exchange between water and phosphate via biochemical reactions a set of culture experiments were conducted. Different species of phytoplankton were grown in seawater at various temperatures, light levels, and phosphate concentrations. The oxygen isotopic composition in the phosphate source, algal cells, and the isotopic composition oxygen in the dissolved inorganic phosphate (DIP) were measured. Results showing the effect of species, temperature, light and P availability on intracellular oxygen isotope exchange between phosphorus compounds and water will be presented. The effect of these parameters on the utility of the oxygen isotopic composition of phosphate as a tracer of phosphate utilization rate in the ocean will be discussed. This information is fundamental to any application of isotopic composition of oxygen of dissolved inorganic or organic phosphate to quantify the dynamics of phosphorus cycling in aquatic systems. The data will be utilized to investigate seasonal changes in phosphate sources and cycling in the open ocean and how these relate to phytoplankton abundance, hydrography, and nutrient concentrations.

  2. Application of lead and strontium isotope ratio measurements for the origin assessment of uranium ore concentrates.

    PubMed

    Varga, Zsolt; Wallenius, Maria; Mayer, Klaus; Keegan, Elizabeth; Millet, Sylvain

    2009-10-15

    Lead and strontium isotope ratios were used for the origin assessment of uranium ore concentrates (yellow cakes) for nuclear forensic purposes. A simple and low-background sample preparation method was developed for the simultaneous separation of the analytes followed by the measurement of the isotope ratios by multicollector inductively coupled plasma mass spectrometry (MC-ICPMS). The lead isotopic composition of the ore concentrates suggests applicability for the verification of the source of the nuclear material and by the use of the radiogenic (207)Pb/(206)Pb ratio the age of the raw ore material can be calculated. However, during data interpretation, the relatively high variation of the lead isotopic composition within the mine site and the generally high contribution of natural lead as technological contamination have to be carefully taken into account. The (87)Sr/(86)Sr isotope ratio is less prone to the variation within one mine site and less affected by the production process, thus it was found to be a more purposeful indicator for the origin assessment and source verification than the lead. The lead and strontium isotope ratios measured and the methodology developed provide information on the initial raw uranium ore used, and thus they can be used for source attribution of the uranium ore concentrates.

  3. Adaptive Beamforming with Inadequate Snapshots

    NASA Astrophysics Data System (ADS)

    YU, Jing; LI, Yaan

    2017-01-01

    In array signal processing, the covariance matrix used to calculate the adaptive weights is often poor estimated when the snapshot number is inadequate. The prior environmental knowledge can be used to make the estimation more accuracy. In this paper, an alternative knowledge-aided adaptive beamforming approach that is robust to low sample support environment is proposed. In this algorithm the covariance matrix used to calculate the optimum weights is constructed by blending a sample covariance matrix and a priori structured covariance matrix. Numerical simulations demonstrate the proposed algorithm has the potential for substantial performance improvement.

  4. Application of non-traditional stable isotopes in analytical ecogeochemistry assessed by MC ICP-MS--A critical review.

    PubMed

    Irrgeher, Johanna; Prohaska, Thomas

    2016-01-01

    Analytical ecogeochemistry is an evolving scientific field dedicated to the development of analytical methods and tools and their application to ecological questions. Traditional stable isotopic systems have been widely explored and have undergone continuous development during the last century. The variations of the isotopic composition of light elements (H, O, N, C, and S) have provided the foundation of stable isotope analysis followed by the analysis of traditional geochemical isotope tracers (e.g., Pb, Sr, Nd, Hf). Questions in a considerable diversity of scientific fields have been addressed, many of which can be assigned to the field of ecogeochemistry. Over the past 15 years, other stable isotopes (e.g., Li, Zn, Cu, Cl) have emerged gradually as novel tools for the investigation of scientific topics that arise in ecosystem research and have enabled novel discoveries and explorations. These systems are often referred to as non-traditional isotopes. The small isotopic differences of interest that are increasingly being addressed for a growing number of isotopic systems represent a challenge to the analytical scientist and push the limits of today's instruments constantly. This underlines the importance of a metrologically sound concept of analytical protocols and procedures and a solid foundation of data processing strategies and uncertainty considerations before these small isotopic variations can be interpreted in the context of applied ecosystem research. This review focuses on the development of isotope research in ecogeochemistry, the requirements for successful detection of small isotopic shifts, and highlights the most recent and innovative applications in the field.

  5. Multiple snapshot colored compressive spectral imager

    NASA Astrophysics Data System (ADS)

    Correa, Claudia V.; Hinojosa, Carlos A.; Arce, Gonzalo R.; Arguello, Henry

    2017-04-01

    The snapshot colored compressive spectral imager (SCCSI) is a recent compressive spectral imaging (CSI) architecture that senses the spatial and spectral information of a scene in a single snapshot by means of a colored mosaic FPA detector and a dispersive element. Commonly, CSI architectures allow multiple snapshot acquisition, yielding improved reconstructions of spatially detailed and spectrally rich scenes. Each snapshot is captured employing a different coding pattern. In principle, SCCSI does not admit multiple snapshots since the pixelated tiling of optical filters is directly attached to the detector. This paper extends the concept of SCCSI to a system admitting multiple snapshot acquisition by rotating the dispersive element, so the dispersed spatio-spectral source is coded and integrated at different detector pixels in each rotation. Thus, a different set of coded projections is captured using the same optical components of the original architecture. The mathematical model of the multishot SCCSI system is presented along with several simulations. Results show that a gain up to 7 dB of peak signal-to-noise ratio is achieved when four SCCSI snapshots are compared to a single snapshot reconstruction. Furthermore, a gain up to 5 dB is obtained with respect to state-of-the-art architecture, the multishot CASSI.

  6. Snapshot advantage: a review of the light collection improvement for parallel high-dimensional measurement systems

    PubMed Central

    Hagen, Nathan; Kester, Robert T.; Gao, Liang; Tkaczyk, Tomasz S.

    2012-01-01

    The snapshot advantage is a large increase in light collection efficiency available to high-dimensional measurement systems that avoid filtering and scanning. After discussing this advantage in the context of imaging spectrometry, where the greatest effort towards developing snapshot systems has been made, we describe the types of measurements where it is applicable. We then generalize it to the larger context of high-dimensional measurements, where the advantage increases geometrically with measurement dimensionality. PMID:22791926

  7. Multi-factorial in vivo stable isotope fractionation: causes, correlations, consequences and applications.

    PubMed

    Schmidt, Hanns-Ludwig; Robins, Richard J; Werner, Roland A

    2015-01-01

    Many physical and chemical processes in living systems are accompanied by isotope fractionation on H, C, N, O and S. Although kinetic or thermodynamic isotope effects are always the basis, their in vivo manifestation is often modulated by secondary influences. These include metabolic branching events or metabolite channeling, metabolite pool sizes, reaction mechanisms, anatomical properties and compartmentation of plants and animals, and climatological or environmental conditions. In the present contribution, the fundamentals of isotope effects and their manifestation under in vivo conditions are outlined. The knowledge about and the understanding of these interferences provide a potent tool for the reconstruction of physiological events in plants and animals, their geographical origin, the history of bulk biomass and the biosynthesis of defined representatives. It allows the use of isotope characteristics of biomass for the elucidation of biochemical pathways and reaction mechanisms and for the reconstruction of climatic, physiological, ecological and environmental conditions during biosynthesis. Thus, it can be used for the origin and authenticity control of food, the study of ecosystems and animal physiology, the reconstruction of present and prehistoric nutrition chains and paleaoclimatological conditions. This is demonstrated by the outline of fundamental and application-orientated examples for all bio-elements. The aim of the review is to inform (advanced) students from various disciplines about the whole potential and the scope of stable isotope characteristics and fractionations and to provide them with a comprehensive introduction to the literature on fundamental aspects and applications.

  8. Strategies for Application of Isotopic Uncertainties in Burnup Credit

    SciTech Connect

    Gauld, I.C.

    2002-12-23

    Uncertainties in the predicted isotopic concentrations in spent nuclear fuel represent one of the largest sources of overall uncertainty in criticality calculations that use burnup credit. The methods used to propagate the uncertainties in the calculated nuclide concentrations to the uncertainty in the predicted neutron multiplication factor (k{sub eff}) of the system can have a significant effect on the uncertainty in the safety margin in criticality calculations and ultimately affect the potential capacity of spent fuel transport and storage casks employing burnup credit. Methods that can provide a more accurate and realistic estimate of the uncertainty may enable increased spent fuel cask capacity and fewer casks needing to be transported, thereby reducing regulatory burden on licensee while maintaining safety for transporting spent fuel. This report surveys several different best-estimate strategies for considering the effects of nuclide uncertainties in burnup-credit analyses. The potential benefits of these strategies are illustrated for a prototypical burnup-credit cask design. The subcritical margin estimated using best-estimate methods is discussed in comparison to the margin estimated using conventional bounding methods of uncertainty propagation. To quantify the comparison, each of the strategies for estimating uncertainty has been performed using a common database of spent fuel isotopic assay measurements for pressurized-light-water reactor fuels and predicted nuclide concentrations obtained using the current version of the SCALE code system. The experimental database applied in this study has been significantly expanded to include new high-enrichment and high-burnup spent fuel assay data recently published for a wide range of important burnup-credit actinides and fission products. Expanded rare earth fission-product measurements performed at the Khlopin Radium Institute in Russia that contain the only known publicly-available measurement for {sup 103

  9. THE SNAPSHOT HUBBLE U-BAND CLUSTER SURVEY (SHUCS). I. SURVEY DESCRIPTION AND FIRST APPLICATION TO THE MIXED STAR CLUSTER POPULATION OF NGC 4041

    SciTech Connect

    Konstantopoulos, I. S.; Smith, L. J.; Adamo, A.; Silva-Villa, E.; Gallagher, J. S.; Ryon, J. E.; Bastian, N.; Westmoquette, M. S.; Zackrisson, E.; Larsen, S. S.; Charlton, J. C.

    2013-05-15

    We present the Snapshot Hubble U-band Cluster Survey (SHUCS), a project aimed at characterizing the star cluster populations of 10 nearby galaxies (d < 23 Mpc, half within Almost-Equal-To 12 Mpc) through new F336W (U-band equivalent) imaging from Wide Field Camera 3, and archival BVI-equivalent data with the Hubble Space Telescope. Completing the UBVI baseline reduces the age-extinction degeneracy of optical colors, thus enabling the measurement of reliable ages and masses for the thousands of clusters covered by our survey. The sample consists chiefly of face-on spiral galaxies at low inclination, in various degrees of isolation (isolated, in group, merging), and includes two active galactic nucleus hosts. This first paper outlines the survey itself, the observational datasets, the analysis methods, and presents a proof-of-concept study of the large-scale properties and star cluster population of NGC 4041, a massive SAbc galaxy at a distance of Almost-Equal-To 23 Mpc, and part of a small grouping of six giant members. We resolve two structural components with distinct stellar populations, a morphology more akin to merging and interacting systems. We also find strong evidence of a truncated, Schechter-type mass function, and a similarly segmented luminosity function. These results indicate that binning must erase much of the substructure present in the mass and luminosity functions, and might account for the conflicting reports on the intrinsic shape of these functions in the literature. We also note a tidal feature in the outskirts of the galaxy in Galaxy Evolution Explorer UV imaging, and follow it up with a comprehensive multi-wavelength study of NGC 4041 and its parent group. We deduce a minor merger as a likely cause of its segmented structure and the observed pattern of a radially decreasing star formation rate. We propose that combining the study of star cluster populations with broadband metrics is not only advantageous, but often easily achievable thorough

  10. The Snapshot Hubble U-band Cluster Survey (SHUCS). I. Survey Description and First Application to the Mixed Star Cluster Population of NGC 4041

    NASA Astrophysics Data System (ADS)

    Konstantopoulos, I. S.; Smith, L. J.; Adamo, A.; Silva-Villa, E.; Gallagher, J. S.; Bastian, N.; Ryon, J. E.; Westmoquette, M. S.; Zackrisson, E.; Larsen, S. S.; Weisz, D. R.; Charlton, J. C.

    2013-05-01

    We present the Snapshot Hubble U-band Cluster Survey (SHUCS), a project aimed at characterizing the star cluster populations of 10 nearby galaxies (d < 23 Mpc, half within ≈12 Mpc) through new F336W (U-band equivalent) imaging from Wide Field Camera 3, and archival BVI-equivalent data with the Hubble Space Telescope. Completing the UBVI baseline reduces the age-extinction degeneracy of optical colors, thus enabling the measurement of reliable ages and masses for the thousands of clusters covered by our survey. The sample consists chiefly of face-on spiral galaxies at low inclination, in various degrees of isolation (isolated, in group, merging), and includes two active galactic nucleus hosts. This first paper outlines the survey itself, the observational datasets, the analysis methods, and presents a proof-of-concept study of the large-scale properties and star cluster population of NGC 4041, a massive SAbc galaxy at a distance of ≈23 Mpc, and part of a small grouping of six giant members. We resolve two structural components with distinct stellar populations, a morphology more akin to merging and interacting systems. We also find strong evidence of a truncated, Schechter-type mass function, and a similarly segmented luminosity function. These results indicate that binning must erase much of the substructure present in the mass and luminosity functions, and might account for the conflicting reports on the intrinsic shape of these functions in the literature. We also note a tidal feature in the outskirts of the galaxy in Galaxy Evolution Explorer UV imaging, and follow it up with a comprehensive multi-wavelength study of NGC 4041 and its parent group. We deduce a minor merger as a likely cause of its segmented structure and the observed pattern of a radially decreasing star formation rate. We propose that combining the study of star cluster populations with broadband metrics is not only advantageous, but often easily achievable thorough archival datasets. Based

  11. An open source Bayesian Monte Carlo isotope mixing model with applications in Earth surface processes

    NASA Astrophysics Data System (ADS)

    Arendt, Carli A.; Aciego, Sarah M.; Hetland, Eric A.

    2015-05-01

    The implementation of isotopic tracers as constraints on source contributions has become increasingly relevant to understanding Earth surface processes. Interpretation of these isotopic tracers has become more accessible with the development of Bayesian Monte Carlo (BMC) mixing models, which allow uncertainty in mixing end-members and provide methodology for systems with multicomponent mixing. This study presents an open source multiple isotope BMC mixing model that is applicable to Earth surface environments with sources exhibiting distinct end-member isotopic signatures. Our model is first applied to new δ18O and δD measurements from the Athabasca Glacier, which showed expected seasonal melt evolution trends and vigorously assessed the statistical relevance of the resulting fraction estimations. To highlight the broad applicability of our model to a variety of Earth surface environments and relevant isotopic systems, we expand our model to two additional case studies: deriving melt sources from δ18O, δD, and 222Rn measurements of Greenland Ice Sheet bulk water samples and assessing nutrient sources from ɛNd and 87Sr/86Sr measurements of Hawaiian soil cores. The model produces results for the Greenland Ice Sheet and Hawaiian soil data sets that are consistent with the originally published fractional contribution estimates. The advantage of this method is that it quantifies the error induced by variability in the end-member compositions, unrealized by the models previously applied to the above case studies. Results from all three case studies demonstrate the broad applicability of this statistical BMC isotopic mixing model for estimating source contribution fractions in a variety of Earth surface systems.

  12. Application of diode lasers to the isotopically selective determination of uranium in oxides by optogalvanic spectroscopy

    SciTech Connect

    Young, J.P.; Barshick, C.M.; Shaw, R.W.; Ramsey, J.M.

    1994-09-01

    We have observed isotopically selective diode laser-excited optogalvanic effects in uranium at 778.42 and 776.19 nm. The samples were natural abundance uranium oxide, as well as depleted (0.3% {sup 235}U), natural (0.7% {sup 235}U) and enriched (9.75% {sup 235}U) uranium metal or powders. The measurements were carried out in a demountable-cathode glow discharge cell. Preliminary evaluations of precision for uranium isotopic ratios measured using this technique suggest that it should have broad analytical applications for uranium and other amenable actinides or lanthanides.

  13. POD-Galerkin reduced-order modeling with adaptive finite element snapshots

    NASA Astrophysics Data System (ADS)

    Ullmann, Sebastian; Rotkvic, Marko; Lang, Jens

    2016-11-01

    We consider model order reduction by proper orthogonal decomposition (POD) for parametrized partial differential equations, where the underlying snapshots are computed with adaptive finite elements. We address computational and theoretical issues arising from the fact that the snapshots are members of different finite element spaces. We propose a method to create a POD-Galerkin model without interpolating the snapshots onto their common finite element mesh. The error of the reduced-order solution is not necessarily Galerkin orthogonal to the reduced space created from space-adapted snapshot. We analyze how this influences the error assessment for POD-Galerkin models of linear elliptic boundary value problems. As a numerical example we consider a two-dimensional convection-diffusion equation with a parametrized convective direction. To illustrate the applicability of our techniques to non-linear time-dependent problems, we present a test case of a two-dimensional viscous Burgers equation with parametrized initial data.

  14. Application of Uranium Isotope Dilution Mass Spectrometry in the preparation of New Certified Reference Materials

    NASA Astrophysics Data System (ADS)

    Hasözbek, A.; Mathew, K. J.; Orlowicz, G.; Srinivasan, B.; Narayanan, U.

    2012-04-01

    Proven measurement techniques play a critical role in the preparation of Certified Reference Materials (CRMs) - those requiring high accuracy and precision in the measurement results. Isotope Dilution Mass Spectrometry (IDMS) is one such measurement method commonly used in the quantitative analysis of uranium in nuclear safeguards and isotope geology applications. In this project, we evaluated the possibility of using some of the uranium isotopic and assay CRMs made earlier by the New Brunswick laboratory as IDMS spikes to define the uranium mass fraction in future preparations of CRMs. Uranium solutions prepared from CRM 112-A (a highly pure uranium metal assay standard) and CRM 115 (a highly pure uranium oxide isotopic and assay standard) were used as spikes in the determination of uranium. Two different thermal ionization mass spectrometer instruments (MAT 261 and TRITON) were used for the isotopic measurements. Standard IDMS equation was used for data reduction to yield results for uranium mass fraction along with uncertainties, the latter calculated according to GUM. The results show that uranium mass fraction measurements can be made with the required accuracy and precision for defining the uranium concentration in new CRMs as well as in routine samples analyses.

  15. LWR reactivity/isotopics code for pedagogical and scoping applications

    SciTech Connect

    AbuZaied, G.; Driscoll, M.J.

    1986-01-01

    A program designated BRICC (Burnup Reactivity and Isotopic Composition Computation), has been programmed for use on microcomputers to permit rapid parametric studies of the neutronics of light water reactor (LWR) assemblies. It is currently employed as a teaching tool in a graduate-level subject on nuclear fuel management, and has proven to be of sufficient accuracy to permit its use as a submodule in a more comprehensive program used to evaluate various mechanical spectral shift concepts for pressurized water reactor control. It should also prove useful in teaching reactor physics as it will fill an important gap between hand calculations of inadequate accuracy and state-of-the-art multigroup programs of daunting complexity. The BRICC program combines a minimum adequate set of old-fashioned phenomenological submodels that describe key physics attributed in an integral fashion, thereby providing the student or researcher with convenient mental pictures to serve as the basis for deductive reasoning. The program is short, written in a simplistic version of the Basic language, with many interspersed Remark statements, and is therefore easy to tinker with for various constructive purposes.

  16. Geochemistry of beryllium isotopes: Applications in geochronometry. Doctoral thesis

    SciTech Connect

    Brown, E.T.

    1990-01-01

    The cosmogenic radioisotope beryllium-10 (half-life= 1.5 Myr) has been determined in suites of samples from tropical river systems and from areas of the oceans influenced by input from the continents, and also within the mineral lattices of quartz grains from Antarctic moraines. These data have been used to investigate the geochemistry of 10Be and apply that knowledge to development of geochronometric techniques. Beryllium-10 is primarily produced by neutron-induced spallation of 14N and 16O in the atmosphere; its flux to the Earth's surface at low latitude was examined through measurements in tropical rainfall. Distributions of 10Be and 9Be (the stable isotope) in dissolved and particulate phases in tropical rivers were used, in conjunction with major ion data, to delineate the geochemical cycle of Be in these river systems. The present work applies in situ cosmogenic production to the examination of the deposition history of moraines of varying ages in Antarctica. It also yields estimates of 10Be and 26Al production rates: 6.4(+5.9-1.5) at/g yr and 42(+20-6) at/g yr at sea level and high geomagnetic latitude.

  17. Isotope Tracers To Study the Environmental Fate and Bioaccumulation of Metal-Containing Engineered Nanoparticles: Techniques and Applications.

    PubMed

    Yin, Yongguang; Tan, Zhiqiang; Hu, Ligang; Yu, Sujuan; Liu, Jingfu; Jiang, Guibin

    2017-03-08

    The rapidly growing applicability of metal-containing engineered nanoparticles (MENPs) has made their environmental fate, biouptake, and transformation important research topics. However, considering the relatively low concentration of MENPs and the high concentration of background metals in the environment and in organisms, tracking the fate of MENPs in environment-related scenarios remains a challenge. Intrinsic labeling of MENPs with radioactive or stable isotopes is a useful tool for the highly sensitive and selective detection of MENPs in the environment and organisms, thus enabling tracing of their transformation, uptake, distribution, and clearance. In this review, we focus on radioactive/stable isotope labeling of MENPs for their environmental and biological tracing. We summarize the advantages of intrinsic radioactive/stable isotopes for MENP labeling and discuss the considerations in labeling isotope selection and preparation of labeled MENPs, as well as exposure routes and detection of labeled MENPs. In addition, current practice in the use of radioactive/stable isotope labeling of MENPs to study their environmental fate and bioaccumulation is reviewed. Future perspectives and potential applications are also discussed, including imaging techniques for radioactive- and stable-isotope-labeled MENPs, hyphenated multistable isotope tracers with speciation analysis, and isotope fractionation as a MENP tracer. It is expected that this critical review could provide the necessary background information to further advance the applications of isotope tracers to study the environmental fate and bioaccumulation of MENPs.

  18. Review of Cyclotrons for the Production of Radioactive Isotopes for Medical and Industrial Applications

    NASA Astrophysics Data System (ADS)

    Schmor, Paul

    2011-02-01

    Radioactive isotopes are used in a wide range of medical, biological, environmental and industrial applications. Cyclotrons are the primary tool for producing the shorter-lived, proton-rich radioisotopes currently used in a variety of medical applications. Although the primary use of the cyclotron-produced short-lived radioisotopes is in PET/CT (positron emission tomography/computed tomography) and SPECT (single photon emission computed tomography) diagnostic medical procedures, cyclotrons are also producing longer-lived isotopes for therapeutic procedures as well as for other industrial and applied science applications. Commercial suppliers of cyclotrons are responding by providing a range of cyclotrons in the energy range of 3-70MeV for the differing needs of the various applications. These cyclotrons generally have multiple beams servicing multiple targets. This review article presents some of the applications of the radioisotopes and provides a comparison of some of the capabilities of the various current cyclotrons. The use of nuclear medicine and the number of cyclotrons supplying the needed isotopes are increasing. It is expected that there will soon be a new generation of small "tabletop" cyclotrons providing patient doses on demand.

  19. Stable isotope applications in biomolecular structure and mechanisms. A meeting to bring together producers and users of stable-isotope-labeled compounds to assess current and future needs

    SciTech Connect

    Trewhella, J.; Cross, T.A.; Unkefer, C.J.

    1994-12-01

    Knowledge of biomolecular structure is a prerequisite for understanding biomolecular function, and stable isotopes play an increasingly important role in structure determination of biological molecules. The first Conference on Stable Isotope Applications in Biomolecular Structure and Mechanisms was held in Santa Fe, New Mexico, March 27--31, 1994. More than 120 participants from 8 countries and 44 institutions reviewed significant developments, discussed the most promising applications for stable isotopes, and addressed future needs and challenges. Participants focused on applications of stable isotopes for studies of the structure and function of proteins, peptides, RNA, and DNA. Recent advances in NMR techniques neutron scattering, EPR, and vibrational spectroscopy were highlighted in addition to the production and synthesis of labeled compounds. This volume includes invited speaker and poster presentations as well as a set of reports from discussion panels that focused on the needs of the scientific community and the potential roles of private industry, the National Stable Isotope Resource, and the National High Magnetic Field Laboratory in serving those needs. This is the leading abstract. Individual papers are processed separately for the database.

  20. Application of neodymium isotope ratio measurements for the origin assessment of uranium ore concentrates.

    PubMed

    Krajkó, Judit; Varga, Zsolt; Yalcintas, Ezgi; Wallenius, Maria; Mayer, Klaus

    2014-11-01

    A novel procedure has been developed for the measurement of (143)Nd/(144)Nd isotope ratio in various uranium-bearing materials, such as uranium ores and ore concentrates (UOC) in order to evaluate the usefulness and applicability of variations of (143)Nd/(144)Nd isotope ratio for provenance assessment in nuclear forensics. Neodymium was separated and pre-concentrated by extraction chromatography and then the isotope ratios were measured by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The method was validated by the measurement of standard reference materials (La Jolla, JB-2 and BCR-2) and the applicability of the procedure was demonstrated by the analysis of uranium samples of world-wide origin. The investigated samples show distinct (143)Nd/(144)Nd ratio depending on the ore type, deposit age and Sm/Nd ratio. Together with other characteristics of the material in question, the Nd isotope ratio is a promising signature for nuclear forensics and suggests being indicative of the source material, the uranium ore.

  1. Analytical application of 2f-wavelength modulation for isotope selective diode laser graphite furnace atomic absorption spectroscopy.

    PubMed

    Wizemann, H D

    2000-01-01

    Experiences in the analytical application of the 2f-wavelength modulation technique for isotope selective atomic absorption spectroscopy in a graphite furnace are reported. Experimental as well as calculated results are presented, mainly for the natural lithium isotopes. Sensitivity, linearity, and (isotope) selectivity are studied by intensity modulation and wavelength modulation. High selectivities can be attained, however, on the cost of detection power. It is shown that the method enables the measurement of lithium isotope ratios larger than 2000 by absorption in a low-pressure graphite tube atomizer.

  2. Electric Vehicles--A Historical Snapshot

    ERIC Educational Resources Information Center

    Kraft, Thomas E.

    2012-01-01

    Most people don't realize that the history of electric vehicles (EVs) predates the Civil War. This article provides a historical snapshot of EVs to spark the interest of both teachers and students in this important transportation technology.

  3. Electric Vehicles--A Historical Snapshot

    ERIC Educational Resources Information Center

    Kraft, Thomas E.

    2012-01-01

    Most people don't realize that the history of electric vehicles (EVs) predates the Civil War. This article provides a historical snapshot of EVs to spark the interest of both teachers and students in this important transportation technology.

  4. Mass-independent isotopic compositions in terrestrial and extraterrestrial solids and their applications.

    PubMed

    Thiemens, M H; Savarino, J; Farquhar, J; Bao, H

    2001-08-01

    In 1983, Thiemens and Heidenreich reported the first chemically produced mass-independent isotope effect. This work has been shown to have a wide range of applications, including atmospheric chemistry, solar system evolution, and chemical physics. This work has recently been reviewed (Weston, R. E. Chem. Rev. 1999, 99, 2115-2136; Thiemens, M. H. Science 1999, 283, 341-345). In this Account, observations of mass-independent isotopic compositions in terrestrial and Martian solids are reviewed. A wide range of applications, including formation and transport of aerosols in the present atmosphere, chemistry of ancient atmospheres and oceans, history and coupling of the atmosphere-surface in the Antarctic dry valleys, origin and evolution of oxygen in the Earth's earliest environment, and the chemistry of the atmosphere and surface of Mars, are discussed.

  5. SnapShot: antiviral restriction factors.

    PubMed

    Kluge, Silvia F; Sauter, Daniel; Kirchhoff, Frank

    2015-10-22

    Restriction factors are cellular proteins that inhibit viruses at different steps of their replication cycle and represent an important first line of defense against viral pathogens. This SnapShot provides an overview of cell-intrinsic antiviral factors, describes their properties, and illustrates the striking variety of antiviral mechanisms as well the sophisticated viral countermeasures. To view this SnapShot, open or download the PDF. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Limited-memory adaptive snapshot selection for proper orthogonal decomposition

    SciTech Connect

    Oxberry, Geoffrey M.; Kostova-Vassilevska, Tanya; Arrighi, Bill; Chand, Kyle

    2015-04-02

    Reduced order models are useful for accelerating simulations in many-query contexts, such as optimization, uncertainty quantification, and sensitivity analysis. However, offline training of reduced order models can have prohibitively expensive memory and floating-point operation costs in high-performance computing applications, where memory per core is limited. To overcome this limitation for proper orthogonal decomposition, we propose a novel adaptive selection method for snapshots in time that limits offline training costs by selecting snapshots according an error control mechanism similar to that found in adaptive time-stepping ordinary differential equation solvers. The error estimator used in this work is related to theory bounding the approximation error in time of proper orthogonal decomposition-based reduced order models, and memory usage is minimized by computing the singular value decomposition using a single-pass incremental algorithm. Results for a viscous Burgers’ test problem demonstrate convergence in the limit as the algorithm error tolerances go to zero; in this limit, the full order model is recovered to within discretization error. The resulting method can be used on supercomputers to generate proper orthogonal decomposition-based reduced order models, or as a subroutine within hyperreduction algorithms that require taking snapshots in time, or within greedy algorithms for sampling parameter space.

  7. A tiny VIS-NIR snapshot multispectral camera

    NASA Astrophysics Data System (ADS)

    Geelen, Bert; Blanch, Carolina; Gonzalez, Pilar; Tack, Nicolaas; Lambrechts, Andy

    2015-03-01

    Spectral imaging can reveal a lot of hidden details about the world around us, but is currently confined to laboratory environments due to the need for complex, costly and bulky cameras. Imec has developed a unique spectral sensor concept in which the spectral unit is monolithically integrated on top of a standard CMOS image sensor at wafer level, hence enabling the design of compact, low cost and high acquisition speed spectral cameras with a high design flexibility. This flexibility has previously been demonstrated by imec in the form of three spectral camera architectures: firstly a high spatial and spectral resolution scanning camera, secondly a multichannel snapshot multispectral camera and thirdly a per-pixel mosaic snapshot spectral camera. These snapshot spectral cameras sense an entire multispectral data cube at one discrete point in time, extending the domain of spectral imaging towards dynamic, video-rate applications. This paper describes the integration of our per-pixel mosaic snapshot spectral sensors inside a tiny, portable and extremely user-friendly camera. Our prototype demonstrator cameras can acquire multispectral image cubes, either of 272x512 pixels over 16 bands in the VIS (470-620nm) or of 217x409 pixels over 25 bands in the VNIR (600-900nm) at 170 cubes per second for normal machine vision illumination levels. The cameras themselves are extremely compact based on Ximea xiQ cameras, measuring only 26x26x30mm, and can be operated from a laptop-based USB3 connection, making them easily deployable in very diverse environments.

  8. Snapshot imaging polarimeters using spatial modulation

    NASA Astrophysics Data System (ADS)

    Luo, Haitao

    The recent demonstration of a novel snapshot imaging polarimeter using the fringe modulation technique shows a promise in building a compact and moving-parts-free device. As just demonstrated in principle, this technique has not been adequately studied. In the effort of advancing this technique, we build a complete theory framework that can address the key issues regarding the polarization aberrations caused by using the functional elements. With this model, we can have the necessary knowledge in designing, analyzing and optimizing the systems. Also, we propose a broader technique that uses arbitrary modulation instead of sinusoidal fringes, which can give us more engineering freedom and can be the solution of achromatizing the system. In the hardware aspect, several important progresses are made. We extend the polarimeter technique from visible to middle wavelength infrared by using the yttrium vanadate crystals. Also, we incorporate a Savart Plate polarimter into a fundus camera to measure the human eye's retinal retardance, useful information for glaucoma diagnosis. Thirdly, a world-smallest imaging polarimeter is proposed and demonstrated, which may open many applications in security, remote sensing and bioscience.

  9. Snapshot Spectral Domain Optical Coherence Tomography

    NASA Astrophysics Data System (ADS)

    Valdez, Ashley

    Optical coherence tomography systems are used to image the retina in 3D to allow ophthalmologists diagnose ocular disease. These systems yield large data sets that are often labor-intensive to analyze and require significant expertise in order to draw conclusions, especially when used over time to monitor disease progression. Spectral Domain Optical Coherence Tomography (SD-OCT) instantly acquires depth profiles at a single location with a broadband source. These systems require mechanical scanning to generate two- or three-dimensional images. Instead of mechanically scanning, a beamlet array was used to permit multiple depth measurements on the retina with a single snapshot using a 3x 3 beamlet array. This multi-channel system was designed, assembled, and tested using a 1 x 2 beamlet lens array instead of a 3 x 3 beamlet array as a proof of concept prototype. The source was a superluminescent diode centered at 840nm with a 45nm bandwidth. Theoretical axial resolution was 6.92um and depth of focus was 3.45mm. Glass samples of varying thickness ranging from 0.18mm to 1.14mm were measured with the system to validate that correct depth profiles can be acquired for each channel. The results demonstrated the prototype system performed as expected, and is ready to be modified for in vivo applicability.

  10. Stirling Isotope Power Systems for Stationary and Mobile Lunar Applications

    NASA Technical Reports Server (NTRS)

    Schmitz, Paul C.; Penswick, L. Barry; Shaltens, Richard K.

    2007-01-01

    The NASA Exploration Systems Architecture Study (ESAS) places a significant emphasis on the development of a wide range of capabilities on the lunar surface as a stepping-stone to further space exploration. An important aspect of developing these capabilities will be the availability of reliable, efficient, and low-mass power systems to support both stationary and mobile applications. One candidate system to provide electrical power is made by coupling the General Purpose Heat Source (GPHS) with a high-performance Stirling convertor. In this paper we explore the practical power range of GPHS/Stirling convertor systems all with conductively coupled hot-end designs for use on the lunar surface. Design and off-design operations during the life of the convertor are studied in addition to considering these varying conditions on system. Unique issues concerning Stirling convertor configurations, integration of the GPHS with the Stirling convertor, controller operation, waste heat rejection, and thermal protection are explored. Of particular importance in the evaluation process is a thorough understanding of the interactions between the wide range of unique lunar environments and the selection of key systems operating characteristics and the power systems design. Additionally, as power levels rise the interface between the GPHS and Stirling and the Stirling and the radiator begins to dominate system mass and material selection becomes more important.

  11. [Applications of stable isotope analysis in the trophic ecology studies of cephalopods].

    PubMed

    Li, Yun-Kai; Gong, Yi; Chen, Xin-Jun

    2014-05-01

    Cephalopods play an important role in marine food webs, however, knowledge about their complex life history, especially their feeding ecology, remains limited. With the rapidly increasing use of stable isotope analysis (SIA) in ecology, it becomes a powerful tool and complement of traditional methods for investigating the trophic ecology and migration patterns of invertebrates. Here, after summarizing the current methods for trophic ecology investigation of cephalopods, applications of SIA in studying the trophic ecology of cephalopods were reviewed, including the key issues such as standardization of available tissues for SIA analyzing, diet shift and migration patterns of cephalopods, with the aim of advancing its application in the biology of cephalopods in the future.

  12. Forensic applications of nitrogen and oxygen isotopes in tracing nitrate sources in urban environments

    USGS Publications Warehouse

    Silva, S.R.; Ging, P.B.; Lee, R.W.; Ebbert, J.C.; Tesoriero, A.J.; Inkpen, E.L.

    2002-01-01

    Ground and surface waters in urban areas are susceptible to nitrate contamination from septic systems, leaking sewer lines, and fertilizer applications. Source identification is a primary step toward a successful remediation plan in affected areas. In this respect, nitrogen and oxygen isotope ratios of nitrate, in conjunction with hydrologic data and water chemistry, have proven valuable in urban studies from Austin, Texas, and Tacoma, Washington. In Austin, stream water was sampled during stremflow and baseflow conditions to assess surface and subsurface sources of nitrate, respectively. In Tacoma, well waters were sampled in adjacent sewered and un-sewered areas to determine if locally high nitrate concentrations were caused by septic systems in the un-sewered areas. In both studies, sewage was identified as a nitrate source and mixing between sewage and other sources of nitrate was apparent. In addition to source identification, combined nitrogen and oxygen isotopes were important in determining the significance of denitrification, which can complicate source assessment by reducing nitrate concentrations and increasing ??15N values. The two studies illustrate the value of nitrogen and oxygen isotopes of nitrate for forensic applications in urban areas. ?? Published by Elsevier Science Ltd. on behalf of AEHS.

  13. Application of nitrogen stable isotope analysis in size-based marine food web and macroecological research.

    PubMed

    Jennings, Simon; Barnes, Carolyn; Sweeting, Christopher J; Polunin, Nicholas V C

    2008-06-01

    Interacting human and environmental pressures influence the structure and dynamics of marine food webs. To describe and predict the effects of these pressures, theoretical advances need to be supported by a capacity to validate the underlying models and assumptions. Here, we review recent applications of nitrogen stable isotope analysis in marine food web and macroecological research, with a focus on work that has paralleled a resurgence of interest in the development and application of size-based models. Nitrogen stable isotope data have been used to estimate intra- and inter-specific variation in trophic level, predator-prey size ratios, transfer efficiency, food chain length, relationships between predator and prey species diversity and the dynamics of energy use. Many of these estimates have contributed to the development, testing and parameterisation of food web and ecosystem models, some of which have been used to establish baselines for assessing the scale of human impacts. The interpretation of results depends on assumed fractionation but, when supported by sensitivity analyses and experimental validation, nitrogen stable isotope data provide valuable insights into the structuring of marine communities and ecosystems. John Wiley & Sons, Ltd

  14. Interpretation of isotopic data in groundwater-rock systems: Model development and application to Sr isotope data from Yucca Mountain

    NASA Astrophysics Data System (ADS)

    Johnson, Thomas M.; Depaolo, Donald J.

    1994-05-01

    A model enabling extraction of hydrologic information from spatial and temporal patterns in measurements of isotope ratios in water-rock systems is presented. The model describes the evolution of isotope ratios in response to solute transport and water-rock interaction. In advective systems, a single dimensionless parameter (a Damköhler number, ND) dominates in determining the distance over which isotopic equilibrium between the water and rock is approached. Some isotope ratios act as conservative tracers (ND ≪ 1), while others reflect only interaction with the local host rock (ND ≫ 1). If ND is close to one (i.e., the distance for equilibration is close to the length scale of observation), isotope ratio measurements can be used to determine ND, which in turn may yield information concerning reaction rates, or spatial variations in water velocity. Zones of high velocity (e.g., as a result of greater fracture density), or less reactive zones, may be identified through observation of their lower ND values. The model is applied to paleohydrologic interpretations of Sr isotope data from calcite fracture fillings in drill cores from Yucca Mountain, Nevada (Marshall et al., 1992). The results agree with other studies suggesting "fast path" transport in the unsaturated zone. Also, we find that the data do not give a conclusive indication of paleowater table elevation because of the effects of water-rock interaction.

  15. High-Temperature Equilibrium Isotope Fractionation of Non-Traditional Stable Isotopes: Experiments, Theory, and Applications (Invited)

    NASA Astrophysics Data System (ADS)

    Young, E. D.; Lazar, G. C.; Macris, C. A.; Manning, C. E.; Schauble, E. A.; Shahar, A.

    2013-12-01

    Experiments are crucial for validating our understanding of stable isotope fractionation at high temperatures. The three-isotope method has been applied with success in the Si, Mg, Fe, and Ni isotope systems to date. The results of these experiments can be compared with expectations from theory and measurements of natural samples. Qualitative insights into the partitioning of heavy and light isotopes between mineral phases are gained by treating the force constant for relevant bonds, Kf j, as electrostatic in origin. The ionic model, based on the mean bond strength as defined by Pauling, has obvious limitations but is useful for rationalizing structures and site occupancies in silicates and oxide minerals and is equally useful in formulating expectations for isotope fractionation between phases. In some cases, as in Fe isotopes in spinels, the expectations are contrary to predictions based on modeling but similar to observations in natural samples. Experimental verification is required. The force constant for a bond between cation i (Mg, Fe, etc.) and anion j (e.g., O) can be written in terms of mean bond strengths si and sj (as defined by Pauling) as Kf,ij = sisj e2 (1-n)/(4 π ɛο r3ij ) where ɛo is the electric constant (vacuum permittivity for simplicity), e is the charge of an electron, n is the exponent in the Born-Mayer formulation for ion repulsion (Born and Mayer 1932), and rij is the interatomic spacing. This equation shows explicitly that larger values for the force constant Kf correspond to smaller coordination numbers (via si and sj). We therefore expect an inverse relationship between isotope ratios (heavy/light) and coordination of its oxygen bond partners in silicate and oxides minerals and this is verified in mantle minerals. Our work with Fe isotope partitioning in mantle spinels suggests that coordination may be equally important as oxidation state, recognizing that these distinctions are not orthogonal. Recent work on the Mg isotopic

  16. Generation of stoichiometric ethylene and isotopic derivatives and application in transition-metal-catalyzed vinylation and enyne metathesis.

    PubMed

    Min, Geanna K; Bjerglund, Klaus; Kramer, Søren; Gøgsig, Thomas M; Lindhardt, Anders T; Skrydstrup, Troels

    2013-12-16

    Ethylene is one of the most important building blocks in industry for the production of polymers and commodity chemicals. (13)C- and D-isotope-labeled ethylenes are also valuable reagents with applications ranging from polymer-structure determination, reaction-mechanism elucidation to the preparation of more complex isotopically labeled compounds. However, these isotopic derivatives are expensive, and are flammable gases, which are difficult to handle. We have developed a method for the controlled generation of ethylene and its isotopic variants including, for the first time, fully isotopically labeled ethylene, from simple alkene precursors by using Ru catalysis. Applying a two-chamber reactor allows both the synthesis of ethylene and its immediate consumption in a chemical transformation permitting reactions to be performed with only stoichiometric amounts of this two carbon olefin. This was demonstrated in the Ni-catalyzed Heck reaction with aryl triflates and benzyl chlorides, as well as Ru-mediated enyne metathesis.

  17. The Modern Marine Ca-isotope Budget and its Application to the Phanerozoic Ca-isotope Record

    NASA Astrophysics Data System (ADS)

    Blattler, C. L.; Jenkyns, H. C.; Henderson, G. M.

    2011-12-01

    Variations in the calcium-isotope ratio (δ44/40Ca) of ancient seawater have been recorded in several studies using marine carbonate, barite, or apatite, but the causes of these variations have not been explored quantitatively. Seawater Ca-isotope ratios are affected by the average fractionation factor between seawater and the carbonate that precipitates from it, which is defined by the composition of the marine carbonate sink. To investigate possible changes in the fractionation factor of marine carbonate over the Phanerozoic, a Ca-isotope budget has been constructed for the modern oceans. Over 250 Ca-isotope measurements have been compiled from a wide variety of carbonate sources to describe the modern marine Ca-isotope budget. This dataset includes over 50 new measurements to characterize several components of the carbonate system, such as coral reefs, which are quantitatively important but have been undersampled, for example, relative to planktic foraminifera. δ44/40Ca values have been temperature-normalized using the relationship of +0.02% per °C, which permits observations and comparisons based on mineralogy, taxonomy, and locus of carbonate precipitation. A general offset of ~0.25%, increasing up to ~0.8% for certain taxa, is observed between subsets of aragonite and calcite samples; no statistical difference is observed between high-Mg calcite and low-Mg calcite. Additionally, within the data for calcite skeletons, two broad groups appear based on taxonomic patterns. Taxa with generally weak control over their biomineralization, such as sclerosponges, brachiopods, and calcareous red algae, are 0.4-0.5% heavier than organisms with more controlled calcification mechanisms, such as coccolithophores and planktic foraminifera. The patterns that emerge from this dataset for different clades demonstrate the usefulness of fossil carbonate for reconstructing the Ca-isotope ratio of ancient seawater. The composition of the modern Ca-isotope budget provides a basis

  18. Field applicability of Compound-Specific Isotope Analysis (CSIA) for characterization and quantification of in situ contaminant degradation in aquifers.

    PubMed

    Braeckevelt, M; Fischer, A; Kästner, M

    2012-06-01

    Microbial processes govern the fate of organic contaminants in aquifers to a major extent. Therefore, the evaluation of in situ biodegradation is essential for the implementation of Natural Attenuation (NA) concepts in groundwater management. Laboratory degradation experiments and biogeochemical approaches are often biased and provide only indirect evidence of in situ degradation potential. Compound-Specific Isotope Analysis (CSIA) is at present among the most promising tools for assessment of the in situ contaminant degradation within aquifers. One- and two-dimensional (2D) CSIA provides qualitative and quantitative information on in situ contaminant transformation; it is applicable for proving in situ degradation and characterizing degradation conditions and reaction mechanisms. However, field application of CSIA is challenging due to a number of influencing factors, namely those affecting the observed isotope fractionation during biodegradation (e.g., non-isotope-fractionating rate-limiting steps, limited bioavailability), potential isotope effects caused by processes other than biodegradation (e.g., sorption, volatilization, diffusion), as well as non-isotope-fractionating physical processes such as dispersion and dilution. This mini-review aims at guiding practical users towards the sound interpretation of CSIA field data for the characterization of in situ contaminant degradation. It focuses on the relevance of various constraints and influencing factors in CSIA field applications and provides advice on when and how to account for these constraints. We first evaluate factors that can influence isotope fractionation during biodegradation, as well as potential isotope-fractionating and non-isotope-fractionating physical processes governing observed isotope fractionation in the field. Finally, the potentials of the CSIA approach for site characterization and the proper ways to account for various constraints are illustrated by means of a comprehensive CSIA field

  19. Sr - an element shows the way - Applications of Sr isotopes for provenance, tracing and migration (Invited)

    NASA Astrophysics Data System (ADS)

    Prohaska, T.; Irrgeher, J.; Zitek, A.; Teschler Nicola, M.

    2010-12-01

    Strontium - named after the small Scottish town Strontian - as such is an element with little popularity. Firstly described by Martin Heinrich Klaproth in 1798, the metal is used in metallurgy to some extent whereas its compounds are interesting in glass industries, electronics and pyrotechnics. The element has chemical similarity to Ca and makes up 1/60 of the earth’s amount of the latter. Nonetheless, it is its isotopic composition which makes Sr so interesting for a large number of scientists. The natural composition of the four naturally occurring isotopes (84Sr, 86Sr 87Sr and 88Sr) varies in nature due to the radioactive decay of 87Rb to 87Sr. Thus, it was early recognized as geochronometer especially in Ca rich matrices. With increasing precision of applied methodology, the natural variation of the 87Sr/86Sr isotope ratio (analyzed at first mainly by thermal ionization mass spectrometry (TIMS)) became more and more popular in provenance studies. The natural variation of the ratio is mainly determined by the geological age and the original composition of the rock and can be used therefore as fingerprint of the local geology. The ratio is transferred with no significant fractionation via the water into plants and finally via the food chain into animal and human tissues (especially bones and teeth). As the element is chemically similar to Ca, it appears in most matrices. The use for provenance studies is supported by the fact that the long half life (4.8 x 1010 years) does not lead to an alteration during the time scales which are investigated (from recent samples to human or animal skeletal remains which date back up to 30.000 BC). The uniqueness of the system besides the natural variation is defined by the ubiquity in nature and the relatively high (and thus measurable) elemental concentration in most tissues. It was finally the advent of multiple collector inductively coupled plasma mass spectrometry (MC-ICP-MS) which augmented the number of applications

  20. RFNC-VNIIEF Capabilities to Production High Pure Isotopes for Scientific and Medical Applications

    SciTech Connect

    Vesnovskii, S. P.

    2002-02-26

    In the technical paper there is presented the information on the basic equipment and more than thirty-year experience of RFNC-VNIIEF activities in the sphere of producing highly enriched isotopes of actinide elements--thorium, uranium, neptunium, plutonium, americium and curium--for scientific researches and practical applications. Electromagnetic separator and radiochemical methods provide obtaining of superpure isotope samples for nuclear-physical radiometric and mass-spectrometric equipment, and also as tracers when analyzing environmental contamination. There are presented the structure of the laboratory occupied with these isotopes electromagnetic separation as well as the nomenclature and characteristics of the specimens supplied. There are stated science and engineering elaborations of technologies aimed at producing alpha-ray radiating radionuclides--thorium-229, thorium-228, actinium-225, radium-224--for the purpose of anti-cancer therapy using bismuth-212 and bismuth-213 produced by the specially developed generators. There are presented the basic directions of cooperation with other Russian Institutes in developing this promising line of conversion.

  1. Ion microprobe measurement of strontium isotopes in calcium carbonate with application to salmon otoliths

    USGS Publications Warehouse

    Weber, P.K.; Bacon, C.R.; Hutcheon, I.D.; Ingram, B.L.; Wooden, J.L.

    2005-01-01

    The ion microprobe has the capability to generate high resolution, high precision isotopic measurements, but analysis of the isotopic composition of strontium, as measured by the 87Sr/ 86Sr ratio, has been hindered by isobaric interferences. Here we report the first high precision measurements of 87Sr/ 86Sr by ion microprobe in calcium carbonate samples with moderate Sr concentrations. We use the high mass resolving power (7000 to 9000 M.R.P.) of the SHRIMP-RG ion microprobe in combination with its high transmission to reduce the number of interfering species while maintaining sufficiently high count rates for precise isotopic measurements. The isobaric interferences are characterized by peak modeling and repeated analyses of standards. We demonstrate that by sample-standard bracketing, 87Sr/86Sr ratios can be measured in inorganic and biogenic carbonates with Sr concentrations between 400 and 1500 ppm with ???2??? external precision (2??) for a single analysis, and subpermil external precision with repeated analyses. Explicit correction for isobaric interferences (peak-stripping) is found to be less accurate and precise than sample-standard bracketing. Spatial resolution is ???25 ??m laterally and 2 ??m deep for a single analysis, consuming on the order of 2 ng of material. The method is tested on otoliths from salmon to demonstrate its accuracy and utility. In these growth-banded aragonitic structures, one-week temporal resolution can be achieved. The analytical method should be applicable to other calcium carbonate samples with similar Sr concentrations. Copyright ?? 2005 Elsevier Ltd.

  2. Snapshot retinal imaging Mueller matrix polarimeter

    NASA Astrophysics Data System (ADS)

    Wang, Yifan; Kudenov, Michael; Kashani, Amir; Schwiegerling, Jim; Escuti, Michael

    2015-09-01

    Early diagnosis of glaucoma, which is a leading cause for visual impairment, is critical for successful treatment. It has been shown that Imaging polarimetry has advantages in early detection of structural changes in the retina. Here, we theoretically and experimentally present a snapshot Mueller Matrix Polarimeter fundus camera, which has the potential to record the polarization-altering characteristics of retina with a single snapshot. It is made by incorporating polarization gratings into a fundus camera design. Complete Mueller Matrix data sets can be obtained by analyzing the polarization fringes projected onto the image plane. In this paper, we describe the experimental implementation of the snapshot retinal imaging Mueller matrix polarimeter (SRIMMP), highlight issues related to calibration, and provide preliminary images acquired from the camera.

  3. "Application of Tunable Diode Laser Spectrometry to Isotopic Studies for Exobiology"

    NASA Technical Reports Server (NTRS)

    Sauke, Todd B.

    1999-01-01

    Computer-controlled electrically-activated valves for rapid gas-handling have been incorporated into the Stable Isotope Laser Spectrometer (SILS) which now permits rapid filling and evacuating of the sample and reference gas cells, Experimental protocols have been developed to take advantage of the fast gas handling capabilities of the instrument and to achieve increased accuracy which results from reduced instrumental drift during rapid isotopic ratio measurements. Using these protocols' accuracies of 0.5 del (0.05%) have been achieved in measurements of 13C/12C in carbon dioxide. Using the small stable isotope laser spectrometer developed in a related PIDDP project of the Co-I, protocols for acquisition of rapid sequential calibration spectra were developed which resulted in 0.5 del accuracy also being achieved in this less complex instrument. An initial version of software for automatic characterization of tunable diode lasers has been developed and diodes have been characterized in order to establish their spectral output properties. A new state-of-the-art high operating temperature (200 K) mid infrared diode laser was purchased (through NASA procurement) and characterized. A thermo-electrically cooled mid infrared tunable diode laser system for use with high temperature operation lasers was developed. In addition to isotopic ratio measurements of carbon and oxygen, measurements of a third biologically important element (15N/14N in N2O gas) have been achieved to a preliminary accuracy of about 0.2%. Transfer of the basic SILS technology to the commercial sector is proceeding under an unfunded Space Act Agreement between NASA and SpiraMed, a medical diagnostic instrument company. Two patents have been issued. Foreign patents based on these two US patents have been applied for and are expected to be issued. A preliminary design was developed for a thermo-electrically cooled SILS instruments for application to planetary space flight exploration missions.

  4. "Application of Tunable Diode Laser Spectrometry to Isotopic Studies for Exobiology"

    NASA Technical Reports Server (NTRS)

    Sauke, Todd B.

    1999-01-01

    Computer-controlled electrically-activated valves for rapid gas-handling have been incorporated into the Stable Isotope Laser Spectrometer (SILS) which now permits rapid filling and evacuating of the sample and reference gas cells, Experimental protocols have been developed to take advantage of the fast gas handling capabilities of the instrument and to achieve increased accuracy which results from reduced instrumental drift during rapid isotopic ratio measurements. Using these protocols' accuracies of 0.5 del (0.05%) have been achieved in measurements of 13C/12C in carbon dioxide. Using the small stable isotope laser spectrometer developed in a related PIDDP project of the Co-I, protocols for acquisition of rapid sequential calibration spectra were developed which resulted in 0.5 del accuracy also being achieved in this less complex instrument. An initial version of software for automatic characterization of tunable diode lasers has been developed and diodes have been characterized in order to establish their spectral output properties. A new state-of-the-art high operating temperature (200 K) mid infrared diode laser was purchased (through NASA procurement) and characterized. A thermo-electrically cooled mid infrared tunable diode laser system for use with high temperature operation lasers was developed. In addition to isotopic ratio measurements of carbon and oxygen, measurements of a third biologically important element (15N/14N in N2O gas) have been achieved to a preliminary accuracy of about 0.2%. Transfer of the basic SILS technology to the commercial sector is proceeding under an unfunded Space Act Agreement between NASA and SpiraMed, a medical diagnostic instrument company. Two patents have been issued. Foreign patents based on these two US patents have been applied for and are expected to be issued. A preliminary design was developed for a thermo-electrically cooled SILS instruments for application to planetary space flight exploration missions.

  5. Snapshots of Enzymatic Baeyer-Villiger Catalysis

    PubMed Central

    Orru, Roberto; Dudek, Hanna M.; Martinoli, Christian; Torres Pazmiño, Daniel E.; Royant, Antoine; Weik, Martin; Fraaije, Marco W.; Mattevi, Andrea

    2011-01-01

    Baeyer-Villiger monooxygenases catalyze the oxidation of carbonylic substrates to ester or lactone products using NADPH as electron donor and molecular oxygen as oxidative reactant. Using protein engineering, kinetics, microspectrophotometry, crystallography, and intermediate analogs, we have captured several snapshots along the catalytic cycle which highlight key features in enzyme catalysis. After acting as electron donor, the enzyme-bound NADP(H) forms an H-bond with the flavin cofactor. This interaction is critical for stabilizing the oxygen-activating flavin-peroxide intermediate that results from the reaction of the reduced cofactor with oxygen. An essential active-site arginine acts as anchoring element for proper binding of the ketone substrate. Its positively charged guanidinium group can enhance the propensity of the substrate to undergo a nucleophilic attack by the flavin-peroxide intermediate. Furthermore, the arginine side chain, together with the NADP+ ribose group, forms the niche that hosts the negatively charged Criegee intermediate that is generated upon reaction of the substrate with the flavin-peroxide. The fascinating ability of Baeyer-Villiger monooxygenases to catalyze a complex multistep catalytic reaction originates from concerted action of this Arg-NADP(H) pair and the flavin subsequently to promote flavin reduction, oxygen activation, tetrahedral intermediate formation, and product synthesis and release. The emerging picture is that these enzymes are mainly oxygen-activating and “Criegee-stabilizing” catalysts that act on any chemically suitable substrate that can diffuse into the active site, emphasizing their potential value as toolboxes for biocatalytic applications. PMID:21697090

  6. Note: Design considerations and characterization of a flexible snapshot hyperspectral probe

    NASA Astrophysics Data System (ADS)

    Lim, Hoong-Ta; Murukeshan, Vadakke Matham

    2017-03-01

    Hyperspectral imaging is a combination of imaging and spectroscopy to give detailed spectral information for each spatial point in the imaged scene. Using the concept of integral field spectroscopy, a custom fabricated two-dimensional to one-dimensional fiber bundle has recently been reported. It is used as a flexible snapshot hyperspectral probe, which can be used as an endoscope for biomedical applications. This paper reports on the design considerations of the fiber bundle as the flexible probe in the snapshot hyperspectral imaging system. The physical characterization of the custom fabricated fiber bundle and lateral resolution of the developed hyperspectral imaging system are also analyzed and described.

  7. Application of LA-MC-ICP-MS for analysis of Sr isotope ratios in speleothems

    NASA Astrophysics Data System (ADS)

    Weber, Michael; Scholz, Denis; Wassenburg, Jasper A.; Jochum, Klaus Peter; Breitenbach, Sebastian

    2017-04-01

    Speleothems are well established climate archives. In order to reconstruct past climate variability, several geochemical proxies, such as δ13C and δ18O as well as trace elements are available. Since several factors influence each individual proxy, robust interpretation is often hampered. This calls for multi-proxy approaches involving additional isotope systems that can help to delineate the role of different sources of water within the epikarst and changes in soil composition. Sr isotope ratios (87Sr/86Sr) have been shown to provide useful information about water residence time and water mixing in the host rock. Furthermore, Sr isotopes are not fractionated during calcite precipitation, implying that the 87Sr/86Sr ratio of the speleothem provides a direct record of the drip water. While most speleothem studies applying Sr isotopes used the TIMS methodology, LA-MC-ICP-MS has been utilized for several other archives, such as otoliths and teeth. This method provides the advantage of faster data acquisition, higher spatial resolution, larger sample throughput and the absence of chemical treatment prior to analysis. Here we present the first LA-MC-ICP-MS Sr isotope data for speleothems. The analytical uncertainty of our LA-MC-ICP-MS Sr data is in a similar range as for other carbonate materials. The results of different ablation techniques (i.e. line scan and spots) are reproducible within error, implying that the application of this technique on speleothems is possible. In addition, several comparative measurements of different carbonate reference materials (i.e. MACS-3, JCt-1, JCp-1), such as tests with standard bracketing and comparison of the 87Sr/86Sr ratios with nanosecond laser ablation system and a state-of-the-art femtosecond laser ablation system, show the robustness of the method. We applied the method to samples from Morocco (Grotte de Piste) and India (Mawmluh Cave). Our results show only very small changes in the 87Sr/86Sr ratios of both speleothems

  8. A review of snapshot multidimensional optical imaging: measuring photon tags in parallel

    PubMed Central

    Gao, Liang; Wang, Lihong V.

    2015-01-01

    Multidimensional optical imaging has seen remarkable growth in the past decade. Rather than measuring only the two-dimensional spatial distribution of light, as in conventional photography, multidimensional optical imaging captures light in up to nine dimensions, providing unprecedented information about incident photons’ spatial coordinates, emittance angles, wavelength, time, and polarization. Multidimensional optical imaging can be accomplished either by scanning or parallel acquisition. Compared with scanning-based imagers, parallel acquisition—also dubbed snapshot imaging—has a prominent advantage in maximizing optical throughput, particularly when measuring a datacube of high dimensions. Here, we first categorize snapshot multidimensional imagers based on their acquisition and image reconstruction strategies, then highlight the snapshot advantage in the context of optical throughput, and finally we discuss their state-of-the-art implementations and applications. PMID:27134340

  9. A review of snapshot multidimensional optical imaging: Measuring photon tags in parallel

    NASA Astrophysics Data System (ADS)

    Gao, Liang; Wang, Lihong V.

    2016-02-01

    Multidimensional optical imaging has seen remarkable growth in the past decade. Rather than measuring only the two-dimensional spatial distribution of light, as in conventional photography, multidimensional optical imaging captures light in up to nine dimensions, providing unprecedented information about incident photons' spatial coordinates, emittance angles, wavelength, time, and polarization. Multidimensional optical imaging can be accomplished either by scanning or parallel acquisition. Compared with scanning-based imagers, parallel acquisition-also dubbed snapshot imaging-has a prominent advantage in maximizing optical throughput, particularly when measuring a datacube of high dimensions. Here, we first categorize snapshot multidimensional imagers based on their acquisition and image reconstruction strategies, then highlight the snapshot advantage in the context of optical throughput, and finally we discuss their state-of-the-art implementations and applications.

  10. Radiogenic Isotopes As Paleoceanographic Tracers in Deep-Sea Corals: Advances in TIMS Measurements of Pb Isotopes and Application to Southern Ocean Corals

    NASA Astrophysics Data System (ADS)

    Wilson, D. J.; van de Flierdt, T.; Bridgestock, L. J.; Paul, M.; Rehkamper, M.; Robinson, L. F.; Adkins, J. F.

    2014-12-01

    Deep-sea corals have emerged as a valuable archive of deep ocean paleoceanographic change, with uranium-series dating providing absolute ages and the potential for centennial resolution. In combination with measurements of radiocarbon, neodymium isotopes and clumped isotopes, this archive has recently been exploited to reconstruct changes in ventilation, water mass sourcing and temperature in relation to millennial climate change. Lead (Pb) isotopes in both corals and seawater have also been used to track anthropogenic inputs through space and time and to trace transport pathways within the oceans. Better understanding of the oceanic Pb cycle is emerging from the GEOTRACES programme. However, while Pb isotopes have been widely used in environmental studies, their full potential as a (pre-anthropogenic) paleoceanographic tracer remains to be exploited. In deep-sea corals, challenges exist from low Pb concentrations in aragonite in comparison to secondary coatings, the potential for contamination, and the efficient elemental separation required for measurement by thermal ionisation mass spectrometry (TIMS). Here we discuss progress in measuring Pb isotopes in coral aragonite using a 207Pb-204Pb double spike on a ThermoFinnigan Triton TIMS. For a 2 ng NIST-981 Pb standard, the long term reproducibility (using 1011 Ω resistors) is ~1000 ppm (2 s.d.) on 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios. We now show that using a new 1012 Ω resistor to measure the small 204Pb beam improves the internal precision on these ratios from ~500 ppm (2 s.e.) to ~250 ppm (2 s.e.) and we envisage a potential improvement in the long term reproducibility as a consequence. We further assess the internal precision and external reproducibility of our method using a BCR-2 rock standard and an in-house coral standard. Preliminary evidence on the application of this method to natural samples is derived from cleaning experiments and replication tests on deep-sea corals from the Southern

  11. CALiPER Snapshot Report: Troffers

    SciTech Connect

    None, None

    2016-12-01

    Snapshot reports use data from DOE's LED Lighting Facts product list to compare the LED performance to standard technologies, and are designed to help lighting retailers, distributors, designers, utilities, energy efficiency program sponsors, and other stakeholders understand the current state of the LED market and its trajectory.

  12. CALiPER Snapshot Report: Light Bulbs

    SciTech Connect

    2013-10-01

    Snapshot reports use data from DOE's LED Lighting Facts product list to compare the LED performance to standard technologies, and are designed to help lighting retailers, distributors, designers, utilities, energy efficiency program sponsors, and other stakeholders understand the current state of the LED market and its trajectory.

  13. A Snapshot of Philadelphia's Accelerated Schools

    ERIC Educational Resources Information Center

    Edmunds, Kimberly; Fonseca, Ean

    2011-01-01

    This snapshot is a guide to the School District of Philadelphia's (the District's) 13 accelerated high schools in the 2010-11 school year. The accelerated high schools were the result of a partnership between the District and Project U-Turn, a city-wide coalition dedicated to reducing student drop-out and increasing graduation rates and readiness…

  14. Gender Equity in Education: A Data Snapshot

    ERIC Educational Resources Information Center

    Office for Civil Rights, US Department of Education, 2012

    2012-01-01

    This data snapshot highlights several differences in educational opportunities between males and females from prekindergarten through higher education. The information herein, gathered from a variety of education data sources, shows that--despite the enormous progress made in ensuring equal educational opportunities since the passage of Title IX…

  15. SnapShot: chronic lymphocytic leukemia.

    PubMed

    Ciccone, Maria; Ferrajoli, Alessandra; Keating, Michael J; Calin, George A

    2014-11-10

    Chronic lymphocytic leukemia (CLL) is the most common leukemia among adults in western countries. This SnapShot depicts the origins and evolution of this B cell malignancy, describes prognostic factors and CLL animal models, and illustrates therapies in preclinical and clinical development against CLL.

  16. CALiPER Snapshot Report: Downlight - 2016

    SciTech Connect

    None, None

    2016-04-01

    Snapshot reports use data from DOE's LED Lighting Facts product list to compare the LED performance to standard technologies, and are designed to help lighting retailers, distributors, designers, utilities, energy efficiency program sponsors, and other stakeholders understand the current state of the LED market and its trajectory.

  17. Assessing Collection Availability: A Snapshot Inventory.

    ERIC Educational Resources Information Center

    Smalley, Topsy N.

    1988-01-01

    Describes the use of "snapshot inventories" to assess the availability of a library collection by measuring the presence/absence of a representative sample of library materials at a given moment. Explains the methods and results of an inventory conducted at Monterey Peninsula College in California. (DMM)

  18. Examining Social Acceptance & Rejection. FPG Snapshot #44

    ERIC Educational Resources Information Center

    FPG Child Development Institute, 2007

    2007-01-01

    This FPG Snapshot summarizes the findings of a study, published in the November 2006 issue of the "Journal of Educational Psychology," that examined whether children with disabilities are accepted or rejected by their classmates in inclusive classrooms. Specifically, the study examined two sets of related questions: (1) Are individual…

  19. High spatial sampling light-guide snapshot spectrometer

    NASA Astrophysics Data System (ADS)

    Wang, Ye; Pawlowski, Michal E.; Tkaczyk, Tomasz S.

    2017-08-01

    A prototype fiber-based imaging spectrometer was developed to provide snapshot hyperspectral imaging tuned for biomedical applications. The system is designed for imaging in the visible spectral range from 400 to 700 nm for compatibility with molecular imaging applications as well as satellite and remote sensing. An 81×96 pixel spatial sampling density is achieved by using a custom-made fiber-optic bundle. The design considerations and fabrication aspects of the fiber bundle and imaging spectrometer are described in detail. Through the custom fiber bundle, the image of a scene of interest is collected and divided into discrete spatial groups, with spaces generated in between groups for spectral dispersion. This reorganized image is scaled down by an image taper for compatibility with following optical elements, dispersed by a prism, and is finally acquired by a CCD camera. To obtain an (x,y,λ) datacube from the snapshot measurement, a spectral calibration algorithm is executed for reconstruction of the spatial-spectral signatures of the observed scene. System characterization of throughput, resolution, and crosstalk was performed. Preliminary results illustrating changes in oxygen-saturation in an occluded human finger are presented to demonstrate the system's capabilities.

  20. Isotope separation by photochromatography

    DOEpatents

    Suslick, K.S.

    1975-10-03

    A photochromatographic method for isotope separation is described. An isotopically mixed molecular species is adsorbed on an adsorptive surface, and the adsorbed molecules are irradiated with radiation of a predetermined wavelength which will selectively excite desired isotopic species. Sufficient energy is transferred to the excited molecules to desorb them from the surface and thus separate them from the undesired isotopic species. The method is particularly applicable to the separation of hydrogen isotopes. (BLM)

  1. Isotope separation by photochromatography

    DOEpatents

    Suslick, Kenneth S.

    1977-01-01

    An isotope separation method which comprises physically adsorbing an isotopically mixed molecular species on an adsorptive surface and irradiating the adsorbed molecules with radiation of a predetermined wavelength which will selectively excite a desired isotopic species. Sufficient energy is transferred to the excited molecules to desorb them from the surface and thereby separate them from the unexcited undesired isotopic species. The method is particularly applicable to the separation of hydrogen isotopes.

  2. Particle Detectors Used in Isotope Ratio Mass Spectrometry, with Applications in Geology, Environmental Science and Nuclear Forensics

    NASA Astrophysics Data System (ADS)

    Lloyd, Nicholas S.; Schwieters, Johannes; Horstwood, Matthew S. A.; Parrish, Randall R.

    This chapter introduces the reader to mass spectrometry and the instruments used to determine high-precision isotope ratios. These instruments separate ion beams, of charged atomic particles with kinetic energies of several keV, by mass-to-charge ratio. Quantitative detection of these energetic charged particles is a key technology in mass spectrometry. For isotope ratio determination the main detector types are Faraday cups, the Daly detector, and discrete dynode secondary electron multiplier (SEM) ion counters. For high-precision applications, arrays of these detectors are arranged to collect several ion beams simultaneously. Examples are given for the application of these detectors in geology, environmental sciences, and nuclear safeguards.

  3. Isotopic chirality

    SciTech Connect

    Floss, H.G.

    1994-12-01

    This paper deals with compounds that are chiral-at least in part, due to isotope substitution-and their use in tracing the steric course of enzyme reaction in vitro and in vivo. There are other applications of isotopically chiral compounds (for example, in analyzing the steric course of nonenzymatic reactions and in probing the conformation of biomolecules) that are important but they will not be discussed in this context.

  4. Review: Current applications and challenges for liquid chromatography coupled to isotope ratio mass spectrometry (LC/IRMS).

    PubMed

    Godin, Jean-Philippe; McCullagh, James S O

    2011-10-30

    High-precision isotope analysis is recognized as an essential research tool in many fields of study. Until recently, continuous flow isotope ratio mass spectrometry (CF-IRMS) was available via an elemental analyzer or a gas chromatography inlet system for compound-specific analysis of light stable isotopes. In 2004, however, an interface that coupled liquid chromatography with IRMS (LC/IRMS) became commercially available for the first time. This brought the capability for new areas of application, in particular enabling compound-specific δ(13)C analysis of non-volatile, aqueous soluble, compounds from complex mixtures. The interface design brought with it several analytical constraints, however, in particular a lack of compatibility with certain types of chromatography as well as limited flow rates and mobile phase compositions. Routine LC/IRMS methods have, however, been established for measuring the δ(13)C isotopic ratios of underivatized individual compounds for application in archeology, nutrition and physiology, geochemistry, hydrology, soil science and food authenticity. Seven years after its introduction, we review the technical advances and constraints, methodological developments and new applications of liquid chromatography coupled to isotope ratio mass spectrometry.

  5. Application of a Stable Isotope Technique for the Bioequivalency Study of Two Transdermal Nitroglycerin Systems.

    PubMed

    Sun, Jim X.; Piraino, Anthony J.; Morgan, John M.; Joshi, Jill C.; Chan, Keith; John, Vivian A.; Good, William R.

    1994-06-01

    A bioequivalency study of an experimental transdermal nitroglycerin system relative to the commercial Transderm-Nitro 0.4 mg/h system was performed on eight healthy volunteers by using an innovative stable isotope technique. Plasma clearance changes for nitroglycerin (NTG) during patch application were corrected with simultaneously administered intravenous infusion of (15)N-labeled nitroglycerin ((15)N-NTG) solution. The total amount of NTG transdermally absorbed (AUC x CL) during a 22-h application for the experimental system was not statistically different from that for the commercial system (9.7 plus minus 3.3 versus 8.1 plus minus 2.6 mg; p = 0.41). The analysis of residual drug content in the used system revealed that the difference in amounts of NTG delivered from the experimental and commercial systems were not significant (12.2 plus minus 3.1 versus 10.8 plus minus 3.1 mg; p = 0.29). With the isotope-labeled method, the absorption rate was evaluated at each time interval during the system application. The peak concentration values were 0.52 plus minus 0.21 mg h(minus sign1) at 1 h for the experimental system and 0.41 plus minus 0.15 mg h(minus sign1) at 2 h for commercial systems. After the peak concentrations, the absorption rates remained constant for both systems over the 16-h period. There was no statistical difference in absorption between the two systems at any sampling time. In this study, substantial fluctuations in the plasma concentrations of both NTG and (15)N-NTG were observed within and between subjects. In addition, the variability in plasma concentrations of NTG correlated well with that of (15)N-NTG for all participating subjects. The momentary changes of clearance, estimated from (15)N-NTG plasma data, were found to be responsible for the fluctuation of NTG in plasma.

  6. Abstracts of the 24th international isotope society (UK group) symposium: synthesis and applications of labelled compounds 2015.

    PubMed

    Aigbirhio, F I; Allwein, S; Anwar, A; Atzrodt, J; Audisio, D; Badman, G; Bakale, R; Berthon, F; Bragg, R; Brindle, K M; Bushby, N; Campos, S; Cant, A A; Chan, M Y T; Colbon, P; Cornelissen, B; Czarny, B; Derdau, V; Dive, V; Dunscombe, M; Eggleston, I; Ellis-Sawyer, K; Elmore, C S; Engstrom, P; Ericsson, C; Fairlamb, I J S; Georgin, D; Godfrey, S P; He, L; Hickey, M J; Huscroft, I T; Kerr, W J; Lashford, A; Lenz, E; Lewinton, S; L'Hermite, M M; Lindelöf, Å; Little, G; Lockley, W J S; Loreau, O; Maddocks, S; Marguerit, M; Mirabello, V; Mudd, R J; Nilsson, G N; Owens, P K; Pascu, S I; Patriarche, G; Pimlott, S L; Pinault, M; Plastow, G; Racys, D T; Reif, J; Rossi, J; Ruan, J; Sarpaki, S; Sephton, S M; Simonsson, R; Speed, D J; Sumal, K; Sutherland, A; Taran, F; Thuleau, A; Wang, Y; Waring, M; Watters, W H; Wu, J; Xiao, J

    2016-04-01

    The 24th annual symposium of the International Isotope Society's United Kingdom Group took place at the Møller Centre, Churchill College, Cambridge, UK on Friday 6th November 2015. The meeting was attended by 77 delegates from academia and industry, the life sciences, chemical, radiochemical and scientific instrument suppliers. Delegates were welcomed by Dr Ken Lawrie (GlaxoSmithKline, UK, chair of the IIS UK group). The subsequent scientific programme consisted of oral presentations, short 'flash' presentations in association with particular posters and poster presentations. The scientific areas covered included isotopic synthesis, regulatory issues, applications of labelled compounds in imaging, isotopic separation and novel chemistry with potential implications for isotopic synthesis. Both short-lived and long-lived isotopes were represented, as were stable isotopes. The symposium was divided into a morning session chaired by Dr Rebekka Hueting (University of Oxford, UK) and afternoon sessions chaired by Dr Sofia Pascu (University of Bath, UK) and by Dr Alan Dowling (Syngenta, UK). The UK meeting concluded with remarks from Dr Ken Lawrie (GlaxoSmithKline, UK). Copyright © 2016 John Wiley & Sons, Ltd.

  7. Isotopic Generation and Confirmation of the PWR Application Model 

    SciTech Connect

    L.B. Wimmer

    2003-11-10

    The objective of this calculation is to establish an isotopic database to represent commercial spent nuclear fuel (CSNF) from pressurized water reactors (PWRs) in criticality analyses performed for the proposed Monitored Geologic Repository at Yucca Mountain, Nevada. Confirmation of the conservatism with respect to criticality in the isotopic concentration values represented by this isotopic database is performed as described in Section 3.5.3.1.2 of the ''Disposal Criticality Analysis Methodology Topical Report'' (YMP 2000). The isotopic database consists of the set of 14 actinides and 15 fission products presented in Section 3.5.2.1.1 of YMP 2000 for use in CSNF burnup credit. This set of 29 isotopes is referred to as the principal isotopes. The oxygen isotope from the UO{sub 2} fuel is also included in the database. The isotopic database covers enrichments of {sup 235}U ranging from 1.5 to 5.5 weight percent (wt%) and burnups ranging from approximately zero to 75 GWd per metric ton of uranium (mtU). The choice of fuel assembly and operating history values used in generating the isotopic database are provided is Section 5. Tables of isotopic concentrations for the 29 principal isotopes (plus oxygen) as a function of enrichment and burnup are provided in Section 6.1. Results of the confirmation of the conservatism with respect to criticality in the isotopic concentration values are provided in Section 6.2.

  8. Stable isotopes in modern ostrich eggshell: a calibration for paleoenvironmental applications in semi-arid regions of southern Africa

    NASA Astrophysics Data System (ADS)

    Johnson, Beverly J.; Fogel, Marilyn L.; Miller, Gifford H.

    1998-07-01

    An isotopic study of modern ostrich eggshell (OES) is presented as a calibration for terrestrial paleoenvironmental applications. The stable carbon and nitrogen isotope fractionations of OES were determined for various organic fractions of eggshell by measuring the isotopic ratios of modern OES samples collected from controlled settings (i.e., zoos and farms) and corresponding ostrich diet. These fractionations were used to evaluate the relationship between the isotope composition of OES laid by free-range birds living in South Africa and their environment. The carbon isotope composition of the total organic and inorganic fractions of OES were enriched by 2 and 16‰, respectively, relative to the diet. In natural settings, the δ 13C values of both the organic and inorganic fractions of OES reflected that of ambient vegetation, with a noted dietary preference for C 3 plants. The nitrogen isotope composition of the total organic fraction of OES was 3‰ enriched relative to the diet, and varied inversely with mean annual precipitation (MAP) in natural settings. A decrease in MAP of 100 mm was accompanied by an increase in δ 15N values of approximately 1‰. The oxygen isotope composition of the inorganic fraction of the OES varied linearly with that of the drinking water in controlled settings. However, in natural settings, the δ 18O of OES values were highly variable and are thought to be controlled primarily by the δ 18O of ingested plant leaf-water. The stability of the isotopic signal in the organic fraction of OES through geologic time was evaluated through a series of heating experiments. The δ 13C and δ 15N values of the total organic fraction of heated OES increased by less than 0.6 and 0.2‰ for carbon and nitrogen, respectively, in spite of extensive diagenetic alteration and changes in the amino acid composition of the samples. The results of this study indicate that the stable carbon and nitrogen isotope composition of OES is relatively stable

  9. Snapshots from deep magma chambers: decoding field observations

    NASA Astrophysics Data System (ADS)

    De Campos, Cristina P.

    2014-05-01

    During the post-orogenic stage of a Neoproterozoic orogen (Araçuaí-West Congo), inversely zoned calc-alkaline to alkaline plutonic structures intruded previous geologic units. Structural measurements, mapping of flow patterns and additional geochemical and isotopic data point towards different compositional domains which have been generated during a time span between 20 to 30 Ma. The result from decades of mapping revealed the architecture of ca. 10 large plutons in more détail. This work will focus on the dynamics of magmatic interaction for six different plutons ranging from c.20 to 200 km2 in outcropping area. Conclusions are based on already published and new unpublished data aiming the state of the art. In the silica-richer structures concentric fragmented and folded layers of granite in a K-basaltic matrix contrast with predominant more homogeneous K-basaltic to gabbroic regions. These may be separated by stretched filament regions (magmatic shear zones) where mixing has been enhanced resulting in hybrid compositions. Locally sharp and pillow-like contacts between granitic and K-basaltic rocks depict a frozen-in situation of different intrusive episodes. In the silica-poorer plutonic bodies gradational contacts are more frequent and may be the result of convection enhanced diffusion. For all plutons, however, mostly sub-vertical internal contacts between most- and least-differentiated rocks suggest generation from predominat large magma bodies of variable composition which crystallized while crossing the middle to lower crust (< 25 km depth). They have been catch in the act on their way up. Accordingly mushroom- to funnel-like magma-chambers and/or conduits could register snapshots of the interaction dynamics between granitic and noritic/dioritic or syeno-monzonitic and gabbroic magmas. Different compositional domains within different plutons suggest distinct kinematics. Nevertheless all studied plutons provide outstanding evidence for mixing, not only

  10. Managing Spatial Selections With Contextual Snapshots

    PubMed Central

    Mindek, P; Gröller, M E; Bruckner, S

    2014-01-01

    Spatial selections are a ubiquitous concept in visualization. By localizing particular features, they can be analysed and compared in different views. However, the semantics of such selections often depend on specific parameter settings and it can be difficult to reconstruct them without additional information. In this paper, we present the concept of contextual snapshots as an effective means for managing spatial selections in visualized data. The selections are automatically associated with the context in which they have been created. Contextual snapshots can also be used as the basis for interactive integrated and linked views, which enable in-place investigation and comparison of multiple visual representations of data. Our approach is implemented as a flexible toolkit with well-defined interfaces for integration into existing systems. We demonstrate the power and generality of our techniques by applying them to several distinct scenarios such as the visualization of simulation data, the analysis of historical documents and the display of anatomical data. PMID:25821284

  11. Application of natural isotope tracers to geothermal research in the Maechan fault zone (N Thailand)

    NASA Astrophysics Data System (ADS)

    Yongprawat, Monthon; Kamdee, Kiatipong; Sauter, Martin; Wiegand, Bettina

    2017-04-01

    Previous geothermal research in Thailand has mainly focused on high-potential geothermal systems such as the active Maechan fault zone, which is located in the northern part of the country. Fang and Maechan hot springs have been the primary targets for power generation and agricultural applications (Apollaro et al. 2015). Here we present a comprehensive survey of chemical and isotopic compositions of thermal waters from six hot springs, well water, and cold surface water samples. This study aims to identify sources of the geothermal waters, hydrodynamic processes and the thermal capacity of the hot springs along the Maechan fault zone. Field parameters, major ions, stable isotopes of hydrogen, oxygen, and carbon, as well as radiocarbon and tritium were investigated. The chemical composition of both thermal waters and cold surface waters is dominated by the Na-HCO3 type. δ2HSMOW and δ18OSMOW data of thermal water and cold surface water plot along a local meteoric water line, suggesting local precipitation as the source of thermal water in the area. δ13CPDB values between -4 to -16 ‰ indicate that dissolved carbon in the thermal water samples is mainly from inorganic carbon sources but some mixture with organic carbon may occur. Radiocarbon analyses (10-20 pMC) suggest ages of more than 10,000 years for the formation of the thermal waters. Tritium concentrations range between 0-0.2 TU. Bibliography Apollaro, C., Vespasiano, G., De Rosa, R., Marini, L. Use of Mean Residence Time and Flowrate of Thermal Waters to Evaluate the Volume of Reservoir Water Contributing to the Natural Discharge and the Related Geothermal Reservoir Volume. Application to Northern Thailand Hot Springs." Geothermics 58: 62-74. 2015.

  12. SnapShot: GI tract development.

    PubMed

    McGrath, Patrick S; Wells, James M

    2015-03-26

    The endoderm germ layer contributes to the respiratory and gastrointestinal (GI) lineages during development, giving rise to an array of specialized epithelial cell types lining organs, including the thyroid, thymus, lungs, liver, biliary system, pancreas, and intestines. This SnapShot timelines and summarizes key stages following gastrulation, including endoderm patterning, organ specification, and organogenesis. A lineage tree of the developing endocrine pancreas is outlined to further illustrate this process.

  13. Forensic applications of light-element stable isotope ratios of Ricinus communis seeds and ricin preparations.

    PubMed

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

    2013-01-01

    Seeds of the castor plant Ricinus communis are of forensic interest because they are the source of the poison ricin. We tested whether stable isotope ratios of castor seeds and ricin preparations can be used as a forensic signature. We collected over 300 castor seed samples worldwide and measured the C, N, O, and H isotope ratios of the whole seeds and oil. We prepared ricin by three different procedures, acetone extraction, salt precipitation, and affinity chromatography, and compared their isotope ratios to those of the source seeds. The N isotope ratios of the ricin samples and source seeds were virtually identical. Therefore, 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 pairwise comparison tests. Stable isotope ratios therefore constitute a valuable forensic signature for ricin preparations. © 2012 American Academy of Forensic Sciences.

  14. High sensitive gas detection and isotopic measurement for the applications of industrial emission online monitoring and air pollution source tracking

    NASA Astrophysics Data System (ADS)

    Dong, Fengzhong; Zhang, Zhirong; Xia, Hua; Cui, Xiaojuan; Pang, Tao; Wu, Bian; Chen, Weidong; Sigrist, Markus

    2015-04-01

    High sensitive gas detection and isotopic measurements have been widely employed in the industrial and safety production. The recent progress made by our group on high sensitive gas detection with technologies of TDLAS, off-axis integrated cavity output spectroscopy (OA-ICOS) and cavity ring-down spectroscopy (CRDS) will be briefly summarized in this report. Some works for field applications of industrial emission online monitoring and gas leakage detection in oil tank farm with TDLAS are first presented, and then part of our most recent researches on isotopic gas detection with OA-ICOS and CRDS for tracking of pollution sources are also introduced.

  15. Stable isotopes in atmospheric water vapor and applications to the hydrologic cycle

    NASA Astrophysics Data System (ADS)

    Galewsky, Joseph; Steen-Larsen, Hans Christian; Field, Robert D.; Worden, John; Risi, Camille; Schneider, Matthias

    2016-12-01

    The measurement and simulation of water vapor isotopic composition has matured rapidly over the last decade, with long-term data sets and comprehensive modeling capabilities now available. Theories for water vapor isotopic composition have been developed by extending the theories that have been used for the isotopic composition of precipitation to include a more nuanced understanding of evaporation, large-scale mixing, deep convection, and kinetic fractionation. The technologies for in situ and remote sensing measurements of water vapor isotopic composition have developed especially rapidly over the last decade, with discrete water vapor sampling methods, based on mass spectroscopy, giving way to laser spectroscopic methods and satellite- and ground-based infrared absorption techniques. The simulation of water vapor isotopic composition has evolved from General Circulation Model (GCM) methods for simulating precipitation isotopic composition to sophisticated isotope-enabled microphysics schemes using higher-order moments for water and ice size distributions. The incorporation of isotopes into GCMs has enabled more detailed diagnostics of the water cycle and has led to improvements in its simulation. The combination of improved measurement and modeling of water vapor isotopic composition opens the door to new advances in our understanding of the atmospheric water cycle, in processes ranging from the marine boundary layer, through deep convection and tropospheric mixing, and into the water cycle of the stratosphere. Finally, studies of the processes governing modern water vapor isotopic composition provide an improved framework for the interpretation of paleoclimate proxy records of the hydrological cycle.

  16. Biomedical applications of accelerator mass spectrometry-isotope measurements at the level of the atom.

    PubMed

    Barker, J; Garner, R C

    1999-01-01

    Accelerator mass spectrometry (AMS) is a nuclear physics technique developed about twenty years ago, that uses the high energy (several MeV) of a tandem Van de Graaff accelerator to measure very small quantities of rare and long-lived isotopes. Elements that are of interest in biomedicine and environmental sciences can be measured, often to parts per quadrillion sensitivity, i.e. zeptomole to attomole levels (10(-21)-10(-18) mole) from milligram samples. This is several orders of magnitude lower than that achievable by conventional decay counting techniques, such as liquid scintillation counting (LSC). AMS was first applied to geochemical, climatological and archaeological areas, such as for radiocarbon dating (Shroud of Turin), but more recently this technology has been used for bioanalytical applications. In this sphere, most work has been conducted using aluminium, calcium and carbon isotopes. The latter is of special interest in drug metabolism studies, where a Phase 1 adsorption, distribution, metabolism and excretion (ADME) study can be conducted using only 10 nanoCurie (37 Bq or ca. 0.9 microSv) amounts or less of 14C-labelled drugs. In the UK, these amounts of radioactivity are below those necessary to request specific regulatory approval from the Department of Health's Administration of Radioactive Substances Advisory Committee (ARSAC), thus saving on valuable development time and resources. In addition, the disposal of these amounts is much less an environmental issue than that associated with microCurie quantities, which are currently used. Also, AMS should bring an opportunity to conduct "first into man" studies without the need for widespread use of animals. Centre for Biomedical Accelerator Mass Spectrometry (CBAMS) Ltd. is the first fully commercial company in the world to offer analytical services using AMS. With its high throughput and relatively low costs per sample analysis, AMS should be of great benefit to the pharmaceutical and biotechnology

  17. Oxygen Isotope of Phytoliths in Modern Wetland Plants and the Application to Paleoclimate Reconstruction

    NASA Astrophysics Data System (ADS)

    Huang, Z.; Webb, E. A.; Longstaffe, F. J.

    2009-05-01

    Because the oxygen-isotope composition of phytoliths in modern plants is controlled primarily by the oxygen- isotope composition of source water, temperature and relative humidity, isotope analyses of ancient phytoliths extracted from soils have the potential to reveal paleoclimate information. A controlled-temperature, growth- chamber experiment was conducted to determine the relationships among temperature, relative humidity, soil water evaporation, plant-water isotope composition and oxygen-isotope composition of phytoliths in cattails and horsetails. Typha, a cattail species that grows in wetland conditions, and Equisetum, a horsetail species that prefers dry soils, were each grown in four separate chambers at 15, 20, 25 and 30 degrees Celsius. The oxygen- and hydrogen-isotope compositions of watering water, soil water, vapour in the growth chambers and plant water from the leaves and stems were analyzed throughout the eight-month long artificial growing season. The oxygen-isotope compositions of phytoliths extracted from the transpiring tissues of the plants at the end of the growing season were also analyzed.The results show that the oxygen-isotope composition of phytoliths is strongly correlated with oxygen isotope composition of average plant water from late growing season, rather than plant water extracted earlier in the season or from the stem, leaf-base or leaf- apex alone. As the temperature increases, the oxygen-isotope fractionation between phytoliths and plant water decreases. This trend is comparable to the oxygen-isotope thermometer equation developed by Shahack- Gross et al. (1996: Geochim. Cosmochim. Acta 60, 3949-3953), but the separation in oxygen-isotope values between silica and water at a given temperature is about 4 ‰ lower. This discrepancy is likely from uncertainties in the oxygen-isotope value of leaf water at the site of phytolith precipitation, which varied over the growing season as a result of fluctuations in relative humidity and

  18. Population-Level Metrics of Trophic Structure Based on Stable Isotopes and Their Application to Invasion Ecology

    PubMed Central

    Jackson, Michelle C.; Donohue, Ian; Jackson, Andrew L.; Britton, J. Robert; Harper, David M.; Grey, Jonathan

    2012-01-01

    Biological invasions are a significant driver of human-induced global change and many ecosystems sustain sympatric invaders. Interactions occurring among these invaders have important implications for ecosystem structure and functioning, yet they are poorly understood. Here we apply newly developed metrics derived from stable isotope data to provide quantitative measures of trophic diversity within populations or species. We then use these to test the hypothesis that sympatric invaders belonging to the same functional feeding group occupy a smaller isotopic niche than their allopatric counterparts. Two introduced, globally important, benthic omnivores, Louisiana swamp crayfish (Procambarus clarkii) and carp (Cyprinus carpio), are sympatric in Lake Naivasha, Kenya. We applied our metrics to an 8-year data set encompassing the establishment of carp in the lake. We found a strong asymmetric interaction between the two invasive populations, as indicated by inverse correlations between carp abundance and measures of crayfish trophic diversity. Lack of isotopic niche overlap between carp and crayfish in the majority of years indicated a predominantly indirect interaction. We suggest that carp-induced habitat alteration reduced the diversity of crayfish prey, resulting in a reduction in the dietary niche of crayfish. Stable isotopes provide an integrated signal of diet over space and time, offering an appropriate scale for the study of population niches, but few isotope studies have retained the often insightful information revealed by variability among individuals in isotope values. Our population metrics incorporate such variation, are robust to the vagaries of sample size and are a useful additional tool to reveal subtle dietary interactions among species. Although we have demonstrated their applicability specifically using a detailed temporal dataset of species invasion in a lake, they have a wide array of potential ecological applications. PMID:22363724

  19. Application of zinc isotope tracer technology in tracing soil heavy metal pollution

    NASA Astrophysics Data System (ADS)

    Norbu, Namkha; Wang, Shuguang; Xu, Yan; Yang, Jianqiang; Liu, Qiang

    2017-08-01

    Recent years the soil heavy metal pollution has become increasingly serious, especially the zinc pollution. Due to the complexity of this problem, in order to prevent and treat the soil pollution, it's crucial to accurately and quickly find out the pollution sources and control them. With the development of stable isotope tracer technology, it's able to determine the composition of zinc isotope. Based on the theory of zinc isotope tracer technique, and by means of doing some latest domestic and overseas literature research about the zinc isotope multi-receiving cups of inductively coupled plasma mass spectrometer (MC-ICP-MS) testing technology, this paper summarized the latest research results about the pollution tracer of zinc isotope, and according to the deficiencies and existing problems of previous research, made outlooks of zinc isotope fractionation mechanism, repository establishment and tracer multiple solutions.

  20. A stable isotope approach and its application for identifying nitrate source and transformation process in water.

    PubMed

    Xu, Shiguo; Kang, Pingping; Sun, Ya

    2016-01-01

    Nitrate contamination of water is a worldwide environmental problem. Recent studies have demonstrated that the nitrogen (N) and oxygen (O) isotopes of nitrate (NO3(-)) can be used to trace nitrogen dynamics including identifying nitrate sources and nitrogen transformation processes. This paper analyzes the current state of identifying nitrate sources and nitrogen transformation processes using N and O isotopes of nitrate. With regard to nitrate sources, δ(15)N-NO3(-) and δ(18)O-NO3(-) values typically vary between sources, allowing the sources to be isotopically fingerprinted. δ(15)N-NO3(-) is often effective at tracing NO(-)3 sources from areas with different land use. δ(18)O-NO3(-) is more useful to identify NO3(-) from atmospheric sources. Isotopic data can be combined with statistical mixing models to quantify the relative contributions of NO3(-) from multiple delineated sources. With regard to N transformation processes, N and O isotopes of nitrate can be used to decipher the degree of nitrogen transformation by such processes as nitrification, assimilation, and denitrification. In some cases, however, isotopic fractionation may alter the isotopic fingerprint associated with the delineated NO3(-) source(s). This problem may be addressed by combining the N and O isotopic data with other types of, including the concentration of selected conservative elements, e.g., chloride (Cl(-)), boron isotope (δ(11)B), and sulfur isotope (δ(35)S) data. Future studies should focus on improving stable isotope mixing models and furthering our understanding of isotopic fractionation by conducting laboratory and field experiments in different environments.

  1. Improvements in RIMS Isotopic Precision: Application to in situ atom-limited analyses

    SciTech Connect

    Levine, J.; Stephan, T.; Savina, M.; Pellin, M.

    2009-03-17

    Resonance ionization mass spectrometry offers high sensitivity and elemental selectivity in microanalysis, but the isotopic precision attainable by this technique has been limited. Here we report instrumental modifications to improve the precision of RIMS isotope ratio measurements. Special attention must be paid to eliminating pulse-to-pulse variations in the time-of-flight mass spectrometer through which the photoions travel, and resonant excitation schemes must be chosen such that the resonance transitions can substantially power-broadened to cover the isotope shifts. We report resonance ionization measurements of chromium isotope ratios with statistics-limited precision better than 1%.

  2. Application of the Rhenium-Osmium Isotopes to the Geochronology of Diamonds

    NASA Astrophysics Data System (ADS)

    Shirey, S. B.; Richardson, S. H.; Pearson, D. G.; Harris, J. W.

    2003-12-01

    The advent of the modern era of high sensitivity and accuracy measurements of Re and Os isotopic compositions by negative thermal ionization mass spectrometry (N-TIMS; Creaser et al, 1991; Volkening et al, 1991) has led to numerous applications of Re-Os isotopes in tracer studies and geochronology. Recent developments in processing blanks (e.g. Richardson et al, 2001) by miniaturization of chemistry (Re <40x10-15g; Os <2x10-15g) permit single sulfide inclusions in minerals such as diamond to be analyzed for their Re-Os isotopic systematics (Pearson et al, 1998; Pearson and Shirey, 1999). Such data on syngenetic inclusions can provide ages on individual macro-diamonds. The microchemistry technique analyses the entire grain, thereby minimizing problems from exsolution. In addition, the low blanks, combined with high sensitivity of N-TIMS allows the analysis of single eclogitic sulfides that are intractable by laser-ICPMS methods This method of diamond geochronology is being applied to diamonds from ancient terranes such as the Kaapvaal-Zimbabwe, Siberian, Slave, and Australian cratons. The work depends on the distribution of mined, diamond-bearing kimberlites, the frequency and size of sulfide inclusions in respective diamond suites and the beneficence of diamond mining companies. A goal of obtaining ages on diamonds is to place diamond formation episodes into the broader framework of the geological processes that create and modify the continental lithosphere. Additionally, diamonds and their inclusions have long held general interest as the most robust containers of ancient minerals from the mantle at depths of 150 km or more. The most detailed application of Re-Os sulfide inclusion ages has been to the evolution of the Kaapvaal-Zimbabwe craton where there exists the widest distribution of mined kimberlites in diverse geologic terrains, the most extensive dataset on silicate inclusion ages and diamond compositions, and recent seismic tomography of the diamond source

  3. Carbon isotope ratio monitoring-gas chromatography mass spectrometric measurements in the marine environment: biomarker sources and paleoclimate applications.

    PubMed

    Tolosa, I; Lopez, J F; Bentaleb, I; Fontugne, M; Grimalt, J O

    1999-09-30

    Some applications in the use of compound-specific isotopic analyses (CSIA) for biomarker source elucidation in the marine environment and its potential applications to paleoclimatology are evaluated in the present study. The potential use of the carbon isotope ratios of marine biomarkers as recorders of CO2 levels has been considered. A significant correlation between delta 13C cholesterol of suspended particulates and seawater CO2 concentrations from the south Indian Ocean has been found. delta 13C composition in biomarkers of different functionalities from three photosynthetic organisms has been examined. Small variations within and between biosynthetically related compound classes have been observed in cyanobacteria. In algae, e.g. diatoms and dinoflagellates, significant differences between the average delta 13C composition of fatty acids and sterols were observed (7.5/1000 and 2/1000, respectively). These differences can be attributed to diverse isotope effects associated with different biosynthetic reactions. Isotopic variations among homologues of the same lipid class have also been observed. In diatoms, variations were up to 5/1000 within each class of fatty acids and sterols and in the dinoflagellate species, these variations were lower than 3/1000. These differences, and particularly the intra-specific shifts in delta 13C lipid composition, must be considered for the correct interpretation of changes in delta 13C molecular signatures in the marine environment.

  4. Forensic SNP genotyping with SNaPshot: Technical considerations for the development and optimization of multiplexed SNP assays.

    PubMed

    Fondevila, M; Børsting, C; Phillips, C; de la Puente, M; Consortium, Euroforen-NoE; Carracedo, A; Morling, N; Lareu, M V

    2017-01-01

    This review explores the key factors that influence the optimization, routine use, and profile interpretation of the SNaPshot single-base extension (SBE) system applied to forensic single-nucleotide polymorphism (SNP) genotyping. Despite being a mainly complimentary DNA genotyping technique to routine STR profiling, use of SNaPshot is an important part of the development of SNP sets for a wide range of forensic applications with these markers, from genotyping highly degraded DNA with very short amplicons to the introduction of SNPs to ascertain the ancestry and physical characteristics of an unidentified contact trace donor. However, this technology, as resourceful as it is, displays several features that depart from the usual STR genotyping far enough to demand a certain degree of expertise from the forensic analyst before tackling the complex casework on which SNaPshot application provides an advantage. In order to provide the basis for developing such expertise, we cover in this paper the most challenging aspects of the SNaPshot technology, focusing on the steps taken to design primer sets, optimize the PCR and single-base extension chemistries, and the important features of the peak patterns observed in typical forensic SNP profiles using SNaPshot. With that purpose in mind, we provide guidelines and troubleshooting for multiplex-SNaPshot-oriented primer design and the resulting capillary electrophoresis (CE) profile interpretation (covering the most commonly observed artifacts and expected departures from the ideal conditions).

  5. Development and Applications of Thallium isotopes: a new proxy tracking the extent of manganese oxide burial

    NASA Astrophysics Data System (ADS)

    Owens, J. D.; Nielsen, S.; Ostrander, C.; Peterson, L. C.; Anbar, A. D.

    2015-12-01

    Thallium (Tl) isotopes are a new and potential powerful paleoredox proxy with the possibility to track bottom water oxygen conditions based on the burial flux of manganese oxides. Thallium has a residence time of ~20 thousand years, which is long enough to render modern oxic seawater conservative with respect to concentration and isotopes. The isotopic signature of Tl in the global ocean is driven mainly by two outputs (1) adsorption onto manganese oxides and (2) low temperature oceanic crust alteration. Importantly, the isotopic inputs of Tl are all nearly the same value; thus, the isotopic composition and flux of the outputs almost exclusively set the seawater signature. For relatively short term redox events it is reasonable to assume that the dominant isotope fractionation process is associated with manganese oxide precipitation because low temperature alteration is controlled by long-term average ocean crust production rates. We present a broad range of modern samples that span several open ocean profiles combined with water column and sediment profiles from the permanently anoxic basins of the Black Sea and Cariaco Basins. The open ocean shows no variation in depth profiles that encompass most of the major water masses in the Atlantic and Southern Oceans. The anoxic basins, however, reveal Tl isotope signatures closer to their inputs, which is likely due to basinal restriction. The authigenic fraction of organic-rich sediments from the Black Sea and Cariaco Basin capture the Tl isotope value of the overlying water column, which shows that Tl isotopes could be applied as a faithful deep time redox proxy. For the first time, we will present new data showing that Tl isotopes is tracking bottom water ocean oxygenation. We are applying this isotope system to ancient samples, testing the spatial and temporal variability of ocean oxygenation coinciding with major biogeochemical events.

  6. Compound-specific isotope analysis. Application to archaeology, biomedical sciences, biosynthesis, environment, extraterrestrial chemistry, food science, forensic science, humic substances, microbiology, organic geochemistry, soil science and sport.

    PubMed

    Lichtfouse, E

    2000-01-01

    The isotopic composition, for example, (14)C/(12)C, (13)C/(12)C, (2)H/(1)H, (15)N/(14)N and (18)O/(16)O, of the elements of matter is heterogeneous. It is ruled by physical, chemical and biological mechanisms. Isotopes can be employed to follow the fate of mineral and organic compounds during biogeochemical transformations. The determination of the isotopic composition of organic substances occurring at trace level in very complex mixtures such as sediments, soils and blood, has been made possible during the last 20 years due to the rapid development of molecular level isotopic techniques. After a brief glance at pioneering studies revealing isotopic breakthroughs at the molecular and intramolecular levels, this paper reviews selected applications of compound-specific isotope analysis in various scientific fields.

  7. Snapshots: Chromatin Control of Viral Infection

    PubMed Central

    Knipe, David M.; Lieberman, Paul M.; Jung, Jae U.; McBride, Alison A.; Morris, Kevin V.; Ott, Melanie; Margolis, David; Nieto, Amelia; Nevels, Michael; Parks, Robin J.; Kristie, Thomas M.

    2012-01-01

    Like their cellular host counterparts, many invading viral pathogens must contend with, modulate, and utilize the host cell’s chromatin machinery to promote efficient lytic infection or control persistent-latent states. While not intended to be comprehensive, this review represents a compilation of conceptual snapshots of the dynamic interplay of viruses with the chromatin environment. Contributions focus on chromatin dynamics during infection, viral circumvention of cellular chromatin repression, chromatin organization of large DNA viruses, tethering and persistence, viral interactions with cellular chromatin modulation machinery, and control of viral latency-reactivation cycles. PMID:23217624

  8. SnapShot: Phosphoregulation of Mitosis.

    PubMed

    Burgess, Andrew; Vuong, Jenny; Rogers, Samuel; Malumbres, Marcos; O'Donoghue, Seán I

    2017-06-15

    During mitosis, a cell divides its duplicated genome into two identical daughter cells. This process must occur without errors to prevent proliferative diseases (e.g., cancer). A key mechanism controlling mitosis is the precise timing of more than 32,000 phosphorylation and dephosphorylation events by a network of kinases and counterbalancing phosphatases. The identity, magnitude, and temporal regulation of these events have emerged recently, largely from advances in mass spectrometry. Here, we show phosphoevents currently believed to be key regulators of mitosis. For an animated version of this SnapShot, please see http://www.cell.com/cell/enhanced/odonoghue2. Copyright © 2017. Published by Elsevier Inc.

  9. OHANA, the AMBER/VLTI Snapshot Survey

    NASA Astrophysics Data System (ADS)

    Rivinius, T.; de Wit, W.; Demers, Z.; Quirrenbach, A.; VLTI Science Operations Team

    2016-11-01

    We report on the OHANA interferometric snapshot survey, carried out by the VLTI group at the Paranal observatory. It makes use of observing time not useful for any other scheduled scientific or technical tasks in the sense of a backup programme, to characterize the mass-loss for early-type stars. The survey employs the combination of AMBER's high spectral and spatial resolution. The spatially unresolved central object provides a reference frame for the fringe properties observed in the light of the continuum.

  10. High-frequency field-deployable isotope analyzer for hydrological applications

    Treesearch

    Elena S.F. Berman; Manish Gupta; Chris Gabrielli; Tina Garland; Jeffrey J. McDonnell

    2009-01-01

    A high-frequency, field-deployable liquid water isotope analyzer was developed. The instrument was deployed for 4 contiguous weeks in the H. J. Andrews Experimental Forest Long-term Ecological Research site in western Oregon, where it was used for real-time measurement of the isotope ratios of precipitation and stream water during three large storm events. We were able...

  11. [Application of stable isotopes in the study of whole-body protein metabolism].

    PubMed

    Tian, Ying; Yang, Xiaoguang; Piao, Jianhua

    2007-11-01

    Stable isotopes are non-radioactive, so they are safe and suitable for the study of human nutrition. In this paper, the principle and main methods of stable isotopic technique in the study of whole-body protein metabolism were introduced. Meanwhile, the advantages and disadvantages of different methods were discussed and the splanchnic metabolism of labeled amino acids was analyzed.

  12. Heterogeneous distribution of Zn stable isotopes in mice and applications to medical sciences

    NASA Astrophysics Data System (ADS)

    Moynier, F.; Fujii, T.; Shaw, A.; Le Borgne, M.

    2013-12-01

    Zinc is required for the function of more than 300 enzymes involved in many metabolic pathways, and is a vital micronutrient for living organisms. To investigate if Zn isotopes could be used to better understand metal homeostasis, as well as a biomarker for diseases, we assessed the distribution of natural Zn isotopes in various mouse tissues. We found that, with respect to Zn isotopes, most mouse organs are isotopically distinct and that the total range of variation within one mouse encompasses the variations observed in the Earth's crust. Therefore, biological activity must have a major impact on the distribution of Zn isotopes in inorganic materials. The most striking aspect of the data is that red blood cells and bones are enriched by ~0.5 per mil in 66Zn relative to 64Zn when compared to serum, and up to ~1 per mil when compared to the brain and liver. This fractionation is well explained by the equilibrium distribution of isotopes between different bonding environments of Zn in different organs. Differences in gender and genetic background did not appear to affect the isotopic distribution of Zn. Together, these results suggest that potential use of Zn isotopes as a tracer for dietary Zn, and for detecting disturbances in Zn metabolism due to pathological conditions.

  13. Application Of Stable Isotope Analysis To Study Temporal Changes In Foraging Ecology In A Highly Endangered Amphibian

    PubMed Central

    Gillespie, J. Hayley

    2013-01-01

    Background Understanding dietary trends for endangered species may be essential to assessing the effects of ecological disturbances such as habitat modification, species introductions or global climate change. Documenting temporal variation in prey selection may also be crucial for understanding population dynamics. However, the rarity, secretive behaviours and obscure microhabitats of some endangered species can make direct foraging observations difficult or impossible. Furthermore, the lethality or invasiveness of some traditional methods of dietary analysis (e.g. gut contents analysis, gastric lavage) makes them inappropriate for such species. Stable isotope analysis facilitates non-lethal, indirect analysis of animal diet that has unrealized potential in the conservation of endangered organisms, particularly amphibians. Methodology/findings I determined proportional contributions of aquatic macroinvertebrate prey to the diet of an endangered aquatic salamander Eurycea sosorum over a two-year period using stable isotope analysis of 13/12C and 15/14N and the Bayesian stable isotope mixing model SIAR. I calculated Strauss’ dietary electivity indices by comparing these proportions with changing relative abundance of potential prey species through time. Stable isotope analyses revealed that a previously unknown prey item (soft-bodied planarian flatworms in the genus Dugesia) made up the majority of E. sosorum diet. Results also demonstrate that E. sosorum is an opportunistic forager capable of diet switching to include a greater proportion of alternative prey when Dugesia populations decline. There is also evidence of intra-population dietary variation. Conclusions/significance Effective application of stable isotope analysis can help circumvent two key limitations commonly experienced by researchers of endangered species: the inability to directly observe these species in nature and the invasiveness or lethality of traditional methods of dietary analysis. This

  14. Calcium isotopes in caves as a proxy for aridity: Modern calibration and application to the 8.2 kyr event

    NASA Astrophysics Data System (ADS)

    Owen, R. A.; Day, C. C.; Hu, C.-Y.; Liu, Y.-H.; Pointing, M. D.; Blättler, C. L.; Henderson, G. M.

    2016-06-01

    We present the first study of Ca isotope cycling in a natural cave system, with measurements of bedrock, dripwater and recently formed carbonate, coupled to a first stalagmite time-series spanning the 8.2 kyr event. Dripwaters at Heshang Cave (Central China; 30°27‧N, 110°25‧E) are isotopically heavy relative to the dolomite bedrock, the result of prior calcite precipitation (PCP) occurring earlier in the drip flow path. A simple Rayleigh fractionation model quantifies the extent of PCP in the modern environment at 36% Ca removal. The observed in situ calcium isotope fractionation factor between dripwater and carbonate is Δ 44 / 42 Ca = - 0.63 ± 0.03 ‰ and does not vary during the annual cycle. Measurements of speleothem carbonate spanning the 8.2 kyr event show the response of Ca isotopes to changing climate. δ44/42Ca increases by 0.35‰ at the onset of the event, coeval with changes in δ18O and Mg/Ca, and remains high for 80 yr. This change is explained by decreased rainfall leading to increased PCP; an interpretation supported by established PCP proxies (Mg/Ca, Sr/Ca and Ba/Ca). Ca isotopes indicate that PCP increased to 60% Ca removal during the event, which, from application of a simple box model, suggests mean annual rainfall decreased by approximately a third in Central China during the 8.2 kyr event. The response of Ca isotopes across this event demonstrates their potential for the assessment of past conditions, including past dripwater flow rates and rainfall.

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

    SciTech Connect

    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.

  16. Application of stable isotope ratio analysis for biodegradation monitoring in groundwater

    USGS Publications Warehouse

    Hatzinger, Paul B.; Böhlke, John Karl; Sturchio, Neil C.

    2013-01-01

    Stable isotope ratio analysis is increasingly being applied as a tool to detect, understand, and quantify biodegradation of organic and inorganic contaminants in groundwater. An important feature of this approach is that it allows degradative losses of contaminants to be distinguished from those caused by non-destructive processes such as dilution, dispersion, and sorption. Recent advances in analytical techniques, and new approaches for interpreting stable isotope data, have expanded the utility of this method while also exposing complications and ambiguities that must be considered in data interpretations. Isotopic analyses of multiple elements in a compound, and multiple compounds in the environment, are being used to distinguish biodegradative pathways by their characteristic isotope effects. Numerical models of contaminant transport, degradation pathways, and isotopic composition are improving quantitative estimates of in situ contaminant degradation rates under realistic environmental conditions.

  17. Molecular docking of balanol to dynamics snapshots of protein kinase A.

    PubMed

    Wong, Chung F; Kua, Jeremy; Zhang, Yingkai; Straatsma, T P; McCammon, J Andrew

    2005-12-01

    Even if the structure of a receptor has been determined experimentally, it may not be a conformation to which a ligand would bind when induced fit effects are significant. Molecular docking using such a receptor structure may thus fail to recognize a ligand to which the receptor can bind with reasonable affinity. Here, we examine one way to alleviate this problem by using an ensemble of receptor conformations generated from a molecular dynamics simulation for molecular docking. Two molecular dynamics simulations were conducted to generate snapshots for protein kinase A: one with the ligand bound, the other without. The ligand, balanol, was then docked to conformations of the receptors presented by these trajectories. The Lamarckian genetic algorithm in Autodock [Goodsell et al. J Mol Recognit 1996;9(1):1-5; Morris et al. J Comput Chem 1998;19(14):1639-1662] was used in the docking. Three ligand models were used: rigid, flexible, and flexible with torsional potentials. When the snapshots were taken from the molecular dynamics simulation of the protein-ligand complex, the correct docking structure could be recovered easily by the docking algorithm in all cases. This was an easier case for challenging the docking algorithm because, by using the structure of the protein in a protein-ligand complex, one essentially assumed that the protein already had a pocket to which the ligand can fit well. However, when the snapshots were taken from the ligand-free protein simulation, which is more useful for a practical application when the structure of the protein-ligand complex is not known, several clusters of structures were found. Of the 10 docking runs for each snapshot, at least one structure was close to the correctly docked structure when the flexible-ligand models were used. We found that a useful way to identify the correctly docked structure was to locate the structure that appeared most frequently as the lowest energy structure in the docking experiments to different

  18. Capon-based single-snapshot DOA estimation in monostatic MIMO radar

    NASA Astrophysics Data System (ADS)

    Hassanien, Aboulnasr; Amin, Moeness G.; Zhang, Yimin D.; Ahmad, Fauzia

    2015-05-01

    We consider the problem of single snapshot direction-of-arrival (DOA) estimation of multiple targets in monostatic multiple-input multiple-output (MIMO) radar. When only a single snapshot is used, the sample covariance matrix of the data becomes non-invertible and, therefore, does not permit application of Capon-based DOA estimation techniques. On the other hand, low-resolution techniques, such as the conventional beamformer, suffer from biased estimation and fail to resolve closely spaced sources. In this paper, we propose a new Capon-based method for DOA estimation in MIMO radar using a single radar pulse. Assuming that the angular locations of the sources are known a priori to be located within a certain spatial sector, we employ multiple transmit beams to focus the transmit energy of multiple orthogonal waveforms within the desired sector. The transmit weight vectors are carefully designed such that they have the same transmit power distribution pattern. As compared to the standard MIMO radar, the proposed approach enables transmitting an arbitrary number of orthogonal waveforms. By using matched-filtering at the receiver, the data associated with each beam is extracted yielding a virtual data snapshot. The total number of virtual snapshots is equal to the number of transmit beams. By choosing the number of transmit beams to be larger than the number of receive elements, it becomes possible to form a full-rank sample covariance matrix. The Capon beamformer is then applied to estimate the DOAs of the targets of interest. The proposed method is shown to have improved DOA estimation performance as compared to conventional single-snapshot DOA estimation methods.

  19. Family Snapshots: A Descriptive Classroom Exercise in Memory and Insight

    ERIC Educational Resources Information Center

    Gladding, Samuel T.; Cox, Elizabeth

    2008-01-01

    "Family Snapshots" are 100-words-or-less descriptive memories of times in the lives of families that highlight poignant moments. They complement other exercises within a family counseling course, including the use of genograms. Modeled after the "Washington Post Magazine"'s series "Life Is Short: Autobiography as Haiku," these snapshots give…

  20. Family Snapshots: A Descriptive Classroom Exercise in Memory and Insight

    ERIC Educational Resources Information Center

    Gladding, Samuel T.; Cox, Elizabeth

    2008-01-01

    "Family Snapshots" are 100-words-or-less descriptive memories of times in the lives of families that highlight poignant moments. They complement other exercises within a family counseling course, including the use of genograms. Modeled after the "Washington Post Magazine"'s series "Life Is Short: Autobiography as Haiku," these snapshots give…

  1. Interpretation and application of carbon isotope ratios in freshwater diatom silica

    PubMed Central

    Webb, Megan; Wynn, Peter M.; Heiri, Oliver; van Hardenbroek, Maarten; Pick, Frances; Russell, James M.; Stott, Andy W.; Leng, Melanie J.

    2016-01-01

    ABSTRACT Carbon incorporated into diatom frustule walls is protected from degradation enabling analysis for carbon isotope composition (δ13Cdiatom). This presents potential for tracing carbon cycles via a single photosynthetic host with well‐constrained ecophysiology. Improved understanding of environmental processes controlling carbon delivery and assimilation is essential to interpret changes in freshwater δ13Cdiatom. Here relationships between water chemistry and δ13Cdiatom from contemporary regional data sets are investigated. Modern diatom and water samples were collected from river catchments within England and lake sediments from across Europe. The data suggest dissolved, biogenically produced carbon supplied proportionately to catchment productivity was critical in the rivers and soft water lakes. However, dissolved carbon from calcareous geology overwhelmed the carbon signature in hard water catchments. Both results demonstrate carbon source characteristics were the most important control on δ13Cdiatom, with a greater impact than productivity. Application of these principles was made to a sediment record from Lake Tanganyika. δ13Cdiatom co‐varied with δ13Cbulk through the last glacial and Holocene. This suggests carbon supply was again dominant and exceeded authigenic demand. This first systematic evaluation of contemporary δ13Cdiatom controls demonstrates that diatoms have the potential to supply a record of carbon cycling through lake catchments from sediment records over millennial timescales. PMID:27656013

  2. HIBAL: A hydrologic-isotopic-balance model for application to paleolake systems

    USGS Publications Warehouse

    Benson, L.; Paillet, F.

    2002-01-01

    A simple hydrologic-isotopic-balance (HIBAL) model for application to paleolake ??18O records is presented. Inputs to the model include discharge, on-lake precipitation, evaporation, and the ??18O values of these fluid fluxes. Monthly values of climatic parameters that govern the fractionation of 18O and 16O during evaporation have been extracted from historical data sets and held constant in the model. The ability of the model to simulate changes in the hydrologic balance and the ??18O evolution of the mixed layer has been demonstrated using measured data from Pyramid Lake, Nevada. Simulations of the response in ??18O to step- and periodic-function changes in fluid inputs indicate that the hydrologic balance and ??18O values lag climate change. Input of reconstructed river discharges and their ??18O values to Pyramid and Walker lakes indicates that minima and maxima in simulated ??18O records correspond to minima and maxima in the reconstructed volume records and that the overall shape of the volume and ??18O records is similar. The model was also used in a simulation of abrupt oscillations in the ??18O values of paleo-Owens Lake, California.

  3. Quantification of protein posttranslational modifications using stable isotope and mass spectrometry I: principles and applications.

    PubMed

    Jiang, Xinzhao Grace; Apostol, Izydor; Luo, Quanzhou; Lewis, Jeffrey; Keener, Ronald; Luo, Shun; Jerums, Matthew; Zhang, Xin; Wypych, Jette; Huang, Gang

    2012-02-15

    With the increased attention to quality by design (QbD) for biopharmaceutical products, there is a demand for accurate and precise quantification methods to monitor critical quality attributes (CQAs). To address this need we have developed a mass spectrometry (MS) based method to quantify a wide range of posttranslational modifications (PTMs) in recombinant proteins using stable isotope-labeled internal standard (SILIS). The SILIS was produced through metabolic labeling where ¹⁵N was uniformly introduced at every nitrogen atom in the studied proteins. To enhance the accuracy of the method, the levels of PTMs in SILIS were quantified using orthogonal analytical techniques. Digestion of an unknown sample mixed with SILIS generates a labeled and a nonlabeled version of each peptide. The nonlabeled and labeled counterparts coelute during RP-HPLC separation but exhibit a sufficient mass difference to be distinguished by MS detection. With the application of SILIS, numerous PTMs can be quantified in a single analysis based on the measured MS signal ratios of ¹⁵N-labeled versus the nonlabeled pairs. Several examples using microbial and mammalian-expressed recombinant proteins demonstrated the principle and utility of this method. The results indicate that SILIS is a valuable methodology in addressing CQAs for the QbD paradigm. Copyright © 2011 Elsevier Inc. All rights reserved.

  4. Application of a Stable Isotope Approach to Evaluate Impact of Changes in Manufacturing Parameters for an Immediate-Release Tablet.

    PubMed

    Parr, Alan; Badman, Geoff; Bowen, Chester L; Coffin, Mark; Gupta, Manish; Jones, Lori; Kurtinecz, Milena; Naderer, Odin; Travis, Eric; Zhu, John; Patel, Parul

    2016-07-01

    There is continued emphasis from the various worldwide regulatory agencies to ensure that the pharmaceutical industry fully understands the products they are developing. This emphasis is seen via development of quality-by-design (QbD) publications and guidelines generated by the International Committee on Harmonization. The challenge to meet these expectations is primarily associated with the generation of in vivo data (eg, pharmacokinetic data) that is resource intensive. A technique reducing the resources needed to generate this in vivo data permits a more extensive application of QbD principles. This paper presents the application of stable isotopes in pharmacokinetic studies. The data show that the use of stable isotopes can significantly reduce the number of subjects required for a study. This reduction in subjects thus translates into a significant reduction in resources and time needed to generate the required in vivo data to support QbD.

  5. Application of isotopes to estimate water ages in variable time scales in surface and groundwaters

    NASA Astrophysics Data System (ADS)

    Kralik, Martin

    2014-05-01

    Water-Isotopes (2H, 3H, 18O) are ideal tracers not only to determine the origin of waters in precipitation, surface water (river + lakes) as well as in groundwater close to the surface and in deep groundwater but also the mean residence time (MRT) in many applied projects as drinking water supply, hydroelectric power plants, road tunnels etc. . Their application has a long history, but must be always evaluated by a feasible hydrogeological concept and/or other isotope and geochemical tracers. In Alpine areas the retention of precipitation in form of snow and ice in the winter half year is indicated by the lowest 18O-values. The snow melt of the highest part of the recharge area is marked by the lowest 18O-values in the river water, but may not coincide with the maximum flow. Time-series of precipitation station in the mountain and on river station indicate the arrival of the peak snow-melt water in the river and in Low-land areas 4-7 month later. Tritium series indicate that MRTs of several Austrian rivers are in the range of 4 - 6 years. The seasonal input variation of in 18O in precipitation and/or river waters can be used to calculate by lumped parameter models MRT of groundwater at a certain well and compare it with lysimeter measurements and transient model simulations. The MRT of the dispersion model is in good agreement with the estimated time calculated by the numerical transport model and the vertical lysimeter measurements. The MRT of spring water was studied by several methods (3H/3He, SF6 and 85Kr) and a long time series of 3H-measurements. The gas tracers are in good agreement in the range of 6-10 year whereas the 3H-series model (dispersion model) indicate ages in the range of 18-23 years. The hydrogeological concept indicate that the precipitation infiltrates in a mountainous karst area, but the transfer into the porous aquifer in the Vienna Basin occurs either through rivers draining away in the basin or through the lateral transport from the karst

  6. Coupled sulfur isotopic and chemical mass transfer modeling: Approach and application to dynamic hydrothermal processes

    SciTech Connect

    Janecky, D.R.

    1988-09-21

    A computational modeling code (EQPSreverse arrowS) has been developed to examine sulfur isotopic distribution pathways coupled with calculations of chemical mass transfer pathways. A post processor approach to EQ6 calculations was chosen so that a variety of isotopic pathways could be examined for each reaction pathway. Two types of major bounding conditions were implemented: (1) equilibrium isotopic exchange between sulfate and sulfide species or exchange only accompanying chemical reduction and oxidation events, and (2) existence or lack of isotopic exchange between solution species and precipitated minerals, parallel to the open and closed chemical system formulations of chemical mass transfer modeling codes. All of the chemical data necessary to explicitly calculate isotopic distribution pathways is generated by most mass transfer modeling codes and can be input to the EQPS code. Routines are built in to directly handle EQ6 tabular files. Chemical reaction models of seafloor hydrothermal vent processes and accompanying sulfur isotopic distribution pathways illustrate the capabilities of coupling EQPSreverse arrowS with EQ6 calculations, including the extent of differences that can exist due to the isotopic bounding condition assumptions described above. 11 refs., 2 figs.

  7. Integrated carbon and chlorine isotope modeling: applications to chlorinated aliphatic hydrocarbons dechlorination.

    PubMed

    Jin, Biao; Haderlein, Stefan B; Rolle, Massimo

    2013-02-05

    We propose a self-consistent method to predict the evolution of carbon and chlorine isotope ratios during degradation of chlorinated hydrocarbons. The method treats explicitly the cleavage of isotopically different C-Cl bonds and thus considers, simultaneously, combined carbon-chlorine isotopologues. To illustrate the proposed modeling approach we focus on the reductive dehalogenation of chlorinated ethenes. We compare our method with the currently available approach, in which carbon and chlorine isotopologues are treated separately. The new approach provides an accurate description of dual-isotope effects regardless of the extent of the isotope fractionation and physical characteristics of the experimental system. We successfully applied the new approach to published experimental results on dehalogenation of chlorinated ethenes both in well-mixed systems and in situations where mass-transfer limitations control the overall rate of biodegradation. The advantages of our self-consistent dual isotope modeling approach proved to be most evident when isotope fractionation factors of carbon and chlorine differed significantly and for systems with mass-transfer limitations, where both physical and (bio)chemical transformation processes affect the observed isotopic values.

  8. The long-solved problem of the best-fit straight line: application to isotopic mixing lines

    NASA Astrophysics Data System (ADS)

    Wehr, Richard; Saleska, Scott R.

    2017-01-01

    It has been almost 50 years since York published an exact and general solution for the best-fit straight line to independent points with normally distributed errors in both x and y. York's solution is highly cited in the geophysical literature but almost unknown outside of it, so that there has been no ebb in the tide of books and papers wrestling with the problem. Much of the post-1969 literature on straight-line fitting has sown confusion not merely by its content but by its very existence. The optimal least-squares fit is already known; the problem is already solved. Here we introduce the non-specialist reader to York's solution and demonstrate its application in the interesting case of the isotopic mixing line, an analytical tool widely used to determine the isotopic signature of trace gas sources for the study of biogeochemical cycles. The most commonly known linear regression methods - ordinary least-squares regression (OLS), geometric mean regression (GMR), and orthogonal distance regression (ODR) - have each been recommended as the best method for fitting isotopic mixing lines. In fact, OLS, GMR, and ODR are all special cases of York's solution that are valid only under particular measurement conditions, and those conditions do not hold in general for isotopic mixing lines. Using Monte Carlo simulations, we quantify the biases in OLS, GMR, and ODR under various conditions and show that York's general - and convenient - solution is always the least biased.

  9. Successful application of lead isotopes in source apportionment, legal proceedings, remediation and monitoring

    SciTech Connect

    Gulson, Brian; Korsch, Michael; Winchester, Wayne; Devenish, Matthew; Hobbs, Thad; Main, Cleve; Smith, Gerard; Rosman, Kevin; Howearth, Lynette; Burn-Nunes, Laurie; Seow, Jimmy; Oxford, Cameron; Yun, Gracie; Gillam, Lindsay; Crisp, Michelle

    2012-01-15

    In late 2006, the seaside community in Esperance Western Australia was alerted to thousands of native bird species dying. The source of the lead (Pb) was determined by Pb isotopes to derive from the handling of Pb carbonate concentrate through the Port, which began in July 2005. Concern was expressed for the impact of this on the community. Our objectives were to employ Pb isotope ratios to evaluate the source of Pb in environmental samples for use in legal proceedings, and for use in remediation and monitoring. Isotope measurements were undertaken of bird livers, plants, drinking water, soil, harbour sediments, air, bulk ceiling dust, gutter sludge, surface swabs and blood. The unique lead isotopic signature of the contaminating Pb carbonate enabled diagnostic apportionment of lead in samples. Apart from some soil and water samples, the proportion of contaminating Pb was >95% in the environmental samples. Lead isotopes were critical in resolving legal proceedings, are being used in the remediation of premises, were used in monitoring of workers involved in the decontamination of the storage facility, and monitoring transport of the concentrate through another port facility. Air samples show the continued presence of contaminant Pb, more than one year after shipping of concentrate ceased, probably arising from dust resuspension. Brief details of the comprehensive testing and cleanup of the Esperance community are provided along with the role of the Community. Lead isotopic analyses can provide significant benefits to regulatory agencies, interested parties, and the community where the signature is able to be characterised with a high degree of certainty. - Highlights: Black-Right-Pointing-Triangle Lead carbonate concentrate. Black-Right-Pointing-Triangle Successful use of Pb isotopes in identifying sources of Pb arising from transport and shipping. Black-Right-Pointing-Triangle Use of Pb isotopes in legal proceedings and their use in cleanup of residences. Black

  10. Variability in carbon isotopic fractionation during biodegradation of chlorinated ethenes: implications for field applications.

    PubMed

    Slater, G F; Lollar, B S; Sleep, B E; Edwards, E A

    2001-03-01

    Stable carbon isotopic analysis has the potential to assess biodegradation of chlorinated ethenes. Significant isotopic shifts, which can be described by Rayleigh enrichment factors, have been observed for the biodegradation of trichloroethlyene (TCE), cis-dichloroethylene (cDCE), and vinyl chloride (VC). However, until this time, no systematic investigation of isotopic fractionation during perchloroethylene (PCE) degradation has been undertaken. In addition, there has been no comparison of isotopic fractionation by different microbial consortia, nor has there been a comparison of isotopic fractionation by consortia generated from the same source, but growing under different conditions. This study characterized carbon isotopic fractionation during reductive dechlorination of the chlorinated ethenes, PCE in particular, for microbial consortia from two different sources growing under different environmental conditions in order to assess the extent to which different microbial consortia result in different fractionation factors. Rayleigh enrichment factors of -13.8@1000, -20.4@1000, and -22.4@1000 were observed for TCE, cDCE, and VC, respectively, for dechlorination by the KB-1 consortium. In contrast, isotopic fractionation during reductive dechlorination of perchloroethylene (PCE) could not always be approximated by a Rayleigh model. Dechlorination by one consortium followed Rayleigh behavior (epsilon = -5.2), while a systematic change in the enrichment factor was observed over the course of PCE degradation by two other consortia. Comparison of all reported enrichment factors for reductive dechlorination of the chlorinated ethenes shows significant variation between experiments. Despite this variability, these results demonstrate that carbon isotopic analysis can provide qualitative evidence of the occurrence and relative extent of microbial reductive dechlorination of the chlorinated ethenes.

  11. Application of Ca stable isotopes to long-term changes in the Ca cycle of a Northern Hardwood forest

    NASA Astrophysics Data System (ADS)

    Kurtz, A. C.; Takagi, K.; Bailey, S. W.; Bullen, T. D.

    2015-12-01

    The Hubbard Brook Ecosystem Study (New Hampshire, USA) presents an unusual opportunity for the application of innovative isotope methods in forest biogeochemistry. Changes in biogeochemical cycling resulting from decades of acid deposition, subsequent reductions in acid deposition, and a series of experimental treatments (harvesting, Ca amendment) have been studied continuously for 60 years at this site. Importantly, researchers have archived soil, water, and vegetation samples for much of the site's history. Our work seeks to complement earlier mass balance studies of Ca cycling by measuring Ca isotope ratios on archived samples. In the first component of our study, we examined the Ca isotopic response to an experimental clearcut in the early 1980's. Earlier work showed that the clearcut promoted dramatic loss of Ca from the watershed, indicated by a 5-fold increase in streamwater Ca concentrations. The mechanism for this loss was unclear as no resolvable changes in soil Ca pools were observed. Our work shows that streamwater dissolved Ca becomes isotopically lighter as Ca concentrations increase. These data are best accounted for by an increase in Ca loss from the soil cation exchange complex. Soil exchangeable δ44Ca itself evolves towards lighter values in the years following the experimental harvest. We interpret this as replenishment of the soil exchange complex by release of isotopically light Ca from root biomass. In the second component of our study, we examine decadal-scale changes in streamwater and soil Ca in an un-manipulated biogeochemical reference watershed. Historical data from Hubbard Brook show that streamwater Ca concentrations began decreasing sharply in the early 1970's, attributed to decreased deposition of both acidity and Ca with the passage of the Clean Air Act. Preliminary data indicate no resolvable change in the average δ44Ca of streamwater, with variability mostly attributable to discharge (flowpath control). Preliminary data

  12. Ra isotopes in trees: Their application to the estimation of heartwood growth rates and tree ages

    NASA Astrophysics Data System (ADS)

    Hancock, Gary J.; Murray, Andrew S.; Brunskill, Gregg J.; Argent, Robert M.

    2006-12-01

    The difficulty in estimating growth rates and ages of tropical and warm-temperate tree species is well known. However, this information has many important environmental applications, including the proper management of native forests and calculating uptake and release of atmospheric carbon. We report the activities of Ra isotopes in the heartwood, sapwood and leaves of six tree species, and use the radial distribution of the 228Ra/226Ra activity ratio in the stem of the tree to estimate the rate of accretion of heartwood. A model is presented in which dissolved Ra in groundwater is taken up by tree roots, translocated to sapwood in a chemically mobile (ion-exchangeable) form, and rendered immobile as it is transferred to heartwood. Uptake of 232Th and 230Th (the parents of 228Ra and 226Ra) is negligible. The rate of heartwood accretion is determined from the radioactive decay of 228Ra (half-life 5.8 years) relative to long-lived 226Ra (half-life 1600 years), and is relevant to growth periods of up to 50 years. By extrapolating the heartwood accretion rate to the entire tree ring record the method also appears to provide realistic estimates of tree age. Eight trees were studied (three of known age, 72, 66 and 35 years), including three Australian hardwood eucalypt species, two mangrove species, and a softwood pine (P. radiata). The method indicates that the rate of growth ring formation is species and climate dependent, varying from 0.7 rings yr-1 for a river red gum (E. camaldulensis) to around 3 rings yr-1 for a tropical mangrove (X. mekongensis).

  13. Boron isotope geochemistry during diagenesis. Part II. Applications to organic-rich sediments

    NASA Astrophysics Data System (ADS)

    Williams, Lynda B.; Hervig, Richard L.; Hutcheon, Ian

    2001-06-01

    The measured clay-water isotope fractionation for boron was applied to natural organic-rich sediments undergoing illitization. Two field areas were chosen that show illitization occurring over a range of temperatures (80-500°C). Samples representing diagenetic temperatures of illitization (80-200°C) are from the Gulf of Mexico sedimentary basin at 4 to 6-km depth in the Eocene Wilcox Fm and Jurassic Norphlet Fm. The higher temperatures of illitization (200-500°C) occur in a contact metamorphic aureole of the Cretaceous Pierre shale near Walsenburg, Colorado. Here the kinetics of the illitization reaction are more rapid than in a slowly subsiding sedimentary basin, but the chemical and mineralogical variations are minimized as complete illitization occurs over a small lateral distance in a single bentonite layer. These studies indicate that B-isotopes provide a more sensitive indicator of fluid variations in sedimentary basins than O-isotopes, and that B-isotope analyses of authigenic illite can be a valuable geochemical tracer of fluid/rock interactions. Boron isotope ratios in authigenic illite (pore filling) and muscovite (stylolites) from reservoir sandstones in the Gulf of Mexico are distinct from adjacent illitic mudstones, whereas the oxygen isotopic ratios show little variation. Fluids in equilibrium with the mudstones cannot precipitate the authigenic clays with higher δ 11B values measured in the hydrocarbon reservoirs. This suggests that the reservoir fluids were not in communication with the adjacent mudstone pore fluids but were introduced from another source area, perhaps carrying a B-isotopic label derived from the hydrocarbon source region. Authigenic illite formed in the Pierre shale meta-bentonite shows large isotopic fractionations of boron (20‰) during illitization at high temperatures. Incorporation of 500 ppm B in illite formed at 500°C shows that illite is a host for B even at metamorphic temperatures. By using the experimentally

  14. IRAC Snapshot Imaging of Red Herschel Galaxies

    NASA Astrophysics Data System (ADS)

    Cooray, Asantha; Nayyeri, Hooshang; Wardlow, Julie; Ivison, Rob; Perez-Fournon, Ismael; Riechers, Dominik; Clements, David; Oliver, Seb; Oteo, Ivan

    2016-08-01

    Wide-field submillimeter surveys with Herschel have produced large samples of rare populations, which provide some of the most stringent constraints on galaxy formation theories. In this proposal we request IRAC observations of 'red' Herschel sources, which are the most extreme DSFGs at z>4. The proposed snapshot IRAC 3.6 and 4.5um data will probe the stellar emission from these systems - complementary data to the far-infrared dust emission that led to their identification. We will use these data to extend the SEDs into the near-IR regime and measure more reliable stellar masses than otherwise available. They will be combined with existing survey data and dedicated follow-up programs to map the evolution of DSFGs as a function of redshift, stellar mass and far-IR luminosity.

  15. Isotopic measurement of speleothem inclusion water in nano-liter quantities: application to stalagmites from Okinawa, Japan

    NASA Astrophysics Data System (ADS)

    Uemura, Ryu; Nakamoto, Masashi; Asami, Ryuji; Mishima, Satoru; Gibo, Masakazu; Masaka, Kosuke; Jin-Ping, Chen; Wu, Chung-Che; Chang, Yu-Wei; Shen, Chuan-Chou

    2015-04-01

    Speleothem inclusion water isotopic compositions are promising new climatic proxies. The applicability, however, is limited by low water content and challenging analytical difficulties. We have developed a precise and accurate isotopic technique based on cavity ring-down spectroscopy with a low sample-amount requirement of 20-260 nL of inclusion water from only 77-286 mg of stalagmite deposits in Gyokusen Cave, Okinawa Island, Japan. The 1σ reproducibility is ±0.24permil for δ18O and ±1.8permil for δD. The small sample size requirement demonstrates that our analytical technique can offer high-resolution inclusion water-based paleoclimate reconstructions. The δ18O and δD values of inclusion water samples from the two most recently layers are within the expected range of isotopic monitoring data for drip water and rainwater at the island. Data inferred from coupled stalagmite δ18O records of coeval inclusion water and carbonate indicate that a cave temperature over the past few decades agrees with instrumental observations. Inferred temperatures at 9-10 thousand years ago (ka) and 26 ka are consistent with previous marine sediment records. Our results support the application fidelity of the proposed technique for speleothem formation deposited under oxygen isotopic equilibrium conditions. However, we observed two biased temperature at the last glacial period: an enrichment of 0.5-1permil in δ13C and δ18O on the fringe carbonate deposition can bias the derived temperature by up to -4 °C. This kinetic fractionation should be carefully evaluated to avoid misleading interpretations.

  16. Preliminary Study: Application of Off-Axis ICOS to Determine Stable Carbon Isotope in Dissolved Inorganic Carbon

    NASA Astrophysics Data System (ADS)

    Kim, Y. T.; Lee, J. M.; Hwang, J. H.; Piao, J.; Woo, N. C.

    2015-12-01

    CO2 is one of the major causes for global climate change. Because stable carbon isotope ratio is used to trace carbon source, several analytical techniques likes IRMS (Isotope Ratio Mass Spectrometry) and LAS (Laser Absorption Spectrometry) were extensively used. Off-axis ICOS, a kind of LAS, has merits on long-term stability and field application, therefore it is widely being used in CCS (Carbon Capture and Storage) field. The aim of this study is to extend the application scope of OA-ICOS to determine dissolved inorganic carbon (DIC). Because OA-ICOS showed dependence of δ13C on CO2 concentration, data processing is required. We tested CO2 Carbon Isotope Analyzer (CCIA-36-EP, Los Gatos Research) with both reference gas (δ13C= -28.28‰) and aqueous solutions prepared by dissolving sodium bicarbonate standards (δ13C= -12.26‰ and +3.96‰). The differences of δ13C between reference and measurement values are plotted by CO2 concentrations, then compared. At first, we checked the similarity between our curve pattern for reference gas and Guillon's research (δ13C= -43.99‰) by other Analyzer. To analyze aqueous samples, more errors can be caused than gas analysis. The carbon isotope fractionation occurs during dissolving standard reagents and extracting DIC as CO2 gas form. This effect is mixed with CO2 concentration dependence effect, therefore the curve patterns are different with that for reference gas. Our experiments are done for various δ13C values. It could be an important point to use OA-ICOS to analyze DIC, too.

  17. Real-time spatial frequency domain imaging by single snapshot multiple frequency demodulation technique

    NASA Astrophysics Data System (ADS)

    Cao, Zili; Lin, Weihao; Chen, Xinlin; Zeng, Bixin; Xu, Min

    2017-02-01

    We have presented a novel Single Snapshot Multiple Frequency Demodulation (SSMD) method enabling single snapshot wide field imaging of optical properties of turbid media in the Spatial Frequency Domain. SSMD makes use of the orthogonality of harmonic functions and extracts the modulation transfer function (MTF) at multiple modulation frequencies and of arbitrary orientations and amplitudes simultaneously from a single structured-illuminated image at once. SSMD not only increases significantly the data acquisition speed and reduces motion artifacts but also exhibits excellent noise suppression in imaging as well. The performance of SSMD-SFDI is demonstrated with experiments on both tissue mimicking phantoms and in vivo for recovering optical properties. SSMD is ideal in the implementation of a real-time spatial frequency domain imaging platform, which will open up SFDI for vast applications in, for example, mapping the optical properties of a dynamic turbid medium or monitoring fast temporal evolutions.

  18. ENVIRONMENTAL ISOTOPES FOR RESOLUTION OF HYDROLOGY PROBLEMS

    EPA Science Inventory

    The use of environmental isotopes as tracers in the hydrosphere is increasing as analytical instrumentation improves and more applications are discovered. There exists still misconceptions on the role of isotopes in resolving hydrology problems. Naturally occurring isotopes in th...

  19. ENVIRONMENTAL ISOTOPES FOR RESOLUTION OF HYDROLOGY PROBLEMS

    EPA Science Inventory

    The use of environmental isotopes as tracers in the hydrosphere is increasing as analytical instrumentation improves and more applications are discovered. There exists still misconceptions on the role of isotopes in resolving hydrology problems. Naturally occurring isotopes in th...

  20. Recent developments in application of stable isotope analysis on agro-product authenticity and traceability.

    PubMed

    Zhao, Yan; Zhang, Bin; Chen, Gang; Chen, Ailiang; Yang, Shuming; Ye, Zhihua

    2014-02-15

    With the globalisation of agro-product markets and convenient transportation of food across countries and continents, the potential for distribution of mis-labelled products increases accordingly, highlighting the need for measures to identify the origin of food. High quality food with identified geographic origin is a concern not only for consumers, but also for agriculture farmers, retailers and administrative authorities. Currently, stable isotope ratio analysis in combination with other chemical methods gradually becomes a promising approach for agro-product authenticity and traceability. In the last five years, a growing number of research papers have been published on tracing agro-products by stable isotope ratio analysis and techniques combining with other instruments. In these reports, the global variety of stable isotope compositions has been investigated, including light elements such as C, N, H, O and S, and heavy isotopes variation such as Sr and B. Several factors also have been considered, including the latitude, altitude, evaporation and climate conditions. In the present paper, an overview is provided on the authenticity and traceability of the agro-products from both animal and plant sources by stable isotope ratio analysis. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Beyond diet reconstruction: stable isotope applications to human physiology, health, and nutrition.

    PubMed

    Reitsema, Laurie J

    2013-01-01

    Analysis of stable carbon and nitrogen isotopes from soft or mineralized tissues is a direct and widely-used technique for modeling diets. In addition to its continued role in paleodiet analysis, stable isotope analysis is now contributing to studies of physiology, disease, and nutrition in archaeological and living human populations. In humans and other animals, dietary uptake and distribution of carbon and nitrogen among mineralized and soft tissue is carried out with varying efficiency due to factors of internal biology. Human pathophysiologies may lead to pathology-influenced isotopic fractionation that can be exploited to understand not just skeletal health and diet, but physiological health and nutrition. This study reviews examples from human biology, non-human animal ecology, biomedicine, and bioarchaeology demonstrating how stable isotope analyses are usefully applied to the study of physiological adaptation and adaptability. Suggestions are made for future directions in applying stable isotope analysis to the study of nutritional stress, disease, and growth and development in living and past human populations. Copyright © 2013 Wiley Periodicals, Inc.

  2. Spinel-olivine-pryoxene equilibrium iron isotopic fractionation and applications to natural peridotites

    SciTech Connect

    Roskosz, Mathieu; Sio, Corliss K. I.; Dauphas, Nicolas; Bi, Wenli; Tissot, Francois L. H.; Hu, Michael Y.; Zhao, Jiyong; Alp, Esen E.

    2015-11-15

    Eight spinel-group minerals were synthesized by a flux-growth method producing spinels with varying composition and Fe3+/Fe-tot ratios. The mean force constants of iron bonds in these minerals were determined by synchrotron nuclear resonant inelastic X-ray scattering (NRIXS) in order to determine the reduced isotopic partition function ratios (beta-factors) of these spinels. The mean force constants are strongly dependent on the Fe3+/Fe-tot of the spinel but are independent, or weakly dependent on other structural and compositional parameters. From our spectroscopic data, it is found that a single redox-dependent calibration line accounts for the effects of Fe3+/Fe-tot on the beta-factors of spinels. This calibration successfully describes the equilibrium Fe isotopes fractionation factors between spinels and silicates (olivine and pyroxenes). Our predictions are in excellent agreement with independent determinations for the equilibrium Fe isotopic fractionations for the magnetite- fayalite and the magnetite-hedenbergite couples. Our calibration applies to the entire range of Fe3+/Fe-tot ratios found in natural spinels and provides a basis for interpreting iron isotopic variations documented in mantle peridotites. Except for a few exceptions, most of the samples measured so far are in isotopic disequilibrium, reflecting metasomatism and partial melting processes.

  3. Application of Fe Isotopes to the Search for Life and Habitable Planets

    NASA Technical Reports Server (NTRS)

    Johnson, Clark M.; Beard, Brian L.; Nealson, Kenneth L.

    2001-01-01

    The relatively new field of Fe isotope geochemistry can make important contributions to tracing the geochemical cycling of Fe, which bears on issues such as metabolic processing of Fe, surface redox conditions, and development of planetary atmospheres and biospheres. It appears that Fe isotope fractionation in nature and the lab spans about 4 per mil (%) in Fe-56/Fe-54, and although this range is small, our new analytical methods produce a precision of +/- 0.05% on sample sizes as small as 100 ng (10(exp -7) g); this now provides us with a sufficient "signal-to-noise" ratio to make this isotope system useful. We review our work in three areas: 1) the terrestrial and lunar rock record, 2) experiments on inorganic fractionation, and 3) experiments involving biological processing of Fe. Additional information is contained in the original extended abstract.

  4. Application of Fe Isotopes to the Search for Life and Habitable Planets

    NASA Technical Reports Server (NTRS)

    Johnson, Clark M.; Beard, Brian L.; Nealson, Kenneth L.

    2001-01-01

    The relatively new field of Fe isotope geochemistry can make important contributions to tracing the geochemical cycling of Fe, which bears on issues such as metabolic processing of Fe, surface redox conditions, and development of planetary atmospheres and biospheres. It appears that Fe isotope fractionation in nature and the lab spans about 4 per mil (%) in Fe-56/Fe-54, and although this range is small, our new analytical methods produce a precision of +/- 0.05% on sample sizes as small as 100 ng (10(exp -7) g); this now provides us with a sufficient "signal-to-noise" ratio to make this isotope system useful. We review our work in three areas: 1) the terrestrial and lunar rock record, 2) experiments on inorganic fractionation, and 3) experiments involving biological processing of Fe. Additional information is contained in the original extended abstract.

  5. Applications of isotopes to tracing sources of solutes and water in shallow systems

    USGS Publications Warehouse

    Kendall, Carol; Krabbenhoft, David P.

    1995-01-01

    New awareness of the potential danger to water supplies posed by the use of agricultural chemicals has focused attention on the nature of groundwater recharge and the mobility of various solutes, especially nitrate and pesticides, in shallow systems. A better understanding of hydrologic flowpaths and solute sources is required to determine the potential impact of sources of contamination on water supplies, to develop management practices for preserving water quality, and to develop remediation plans for sites that are already contaminated. In many cases, environmental isotopes can be employed as 'surgical tools' for answering very specific questions about water and solute sources. Isotopic data can often provide more accurate information about the system than hydrologic measurements or complicated hydrologic models. This note focuses on practical and cost-effective examples of how naturally-occurring isotopes can be used to track water and solutes as they move through shallow systems.

  6. High-Precision Selenium Isotope Analysis by Hydride Generation MC-ICP-MS: Environmental Applications

    NASA Astrophysics Data System (ADS)

    Schmidberger, S.; Simonetti, A.; Gariépy, C.

    2003-04-01

    The global cycle and the natural isotopic variation of Se in the lithosphere, biosphere, hydrosphere and atmosphere are currently little constrained. The study of Se isotope systematics by negative thermal ionization mass spectrometry (NTIMS) has documented large Se isotope variations up to 15 ppm in various natural samples (δ80Se/76Se; Johnson et al., 1999), indicating its important potential as a tracer in geological and biological processes. Recently, Se isotope measurements on sulfide deposits from hydrothermal systems were obtained using a Micromass IsoProbe multicollector inductively coupled plasma mass spectrometer coupled to a hydride generator (Rouxel et al. 2002). This technique allows for high-precision Se isotope analysis on small sample sizes (<= 100 ng), and thus is a prerequisite for precise Se isotope measurements in low abundance samples such as precipitations, freshwaters and atmospheric aerosols (1 ppb or less). We have developed a 74-82Se double spike technique, which corrects for instrumental mass fractionation during both isotopic analysis and chemical processing. During double spike calibration, mass discrimination was monitored using a Germanium Specpuretextregistered standard (25 ppb). The isotopic composition of the Ge standard was accurately determined using a 10 ppb solution of the isotopic Gallium standard SRM 994. Repeated measurements (n=8) of the Ge standard yielded an external reproducibility of 0.13 ppm and a 74Ge/72Ge ratio of 1.32987. Instrumental mass bias evaluated with the Ge standard was essentially invariant over a three-month period. Our results yield an external reproducibility of 0.4 ppm (80Se/76Se) for a 100 ppb solution of the Se standard SRM 3149 (˜100 ng of total Se consumed). This ongoing study focuses on determining the Se isotopic compositions of precipitations and aerosol samples from remote and urban areas in northeastern North America. The preliminary results for precipitation samples (˜100 to 300 ml of rain

  7. Application of stable isotopes and hydrochemical analysis in groundwater aquifers of Argolis Peninsula (Greece).

    PubMed

    Matiatos, Ioannis; Alexopoulos, Apostolos

    2011-12-01

    The present study examines the isotopic and hydrochemical composition of 18 inland spring waters and 3 coastal karstic spring waters, covering the period between October 2005 and March 2008. The stable isotopes ((18)O, (2)H) processing has revealed the absence of significant evaporation phenomena and that the origin of fresh water samples is meteoric. Using (18)O values in rainfall waters, an average line of isotopic depletion with altitude has been constructed, extracting a rate of-0.45‰/100 m as typical for the study area. Furthermore, the mean altitude of recharge of the springs has been estimated by plotting the groundwater sampling points on a δ(18)O versus altitude diagram. Hydrochemistry results have shown that the dissolution of carbonate, flysch and ophiolitic formations defines the hydrochemical characteristics of groundwater. Moreover, seawater intrusion in the coastal area is significantly high, causing the water in the three karstic springs to be brackish.

  8. Successful application of lead isotopes in source apportionment, legal proceedings, remediation and monitoring.

    PubMed

    Gulson, Brian; Korsch, Michael; Winchester, Wayne; Devenish, Matthew; Hobbs, Thad; Main, Cleve; Smith, Gerard; Rosman, Kevin; Howearth, Lynette; Burn-Nunes, Laurie; Seow, Jimmy; Oxford, Cameron; Yun, Gracie; Gillam, Lindsay; Crisp, Michelle

    2012-01-01

    In late 2006, the seaside community in Esperance Western Australia was alerted to thousands of native bird species dying. The source of the lead (Pb) was determined by Pb isotopes to derive from the handling of Pb carbonate concentrate through the Port, which began in July 2005. Concern was expressed for the impact of this on the community. Our objectives were to employ Pb isotope ratios to evaluate the source of Pb in environmental samples for use in legal proceedings, and for use in remediation and monitoring. Isotope measurements were undertaken of bird livers, plants, drinking water, soil, harbour sediments, air, bulk ceiling dust, gutter sludge, surface swabs and blood. The unique lead isotopic signature of the contaminating Pb carbonate enabled diagnostic apportionment of lead in samples. Apart from some soil and water samples, the proportion of contaminating Pb was >95% in the environmental samples. Lead isotopes were critical in resolving legal proceedings, are being used in the remediation of premises, were used in monitoring of workers involved in the decontamination of the storage facility, and monitoring transport of the concentrate through another port facility. Air samples show the continued presence of contaminant Pb, more than one year after shipping of concentrate ceased, probably arising from dust resuspension. Brief details of the comprehensive testing and cleanup of the Esperance community are provided along with the role of the Community. Lead isotopic analyses can provide significant benefits to regulatory agencies, interested parties, and the community where the signature is able to be characterised with a high degree of certainty.

  9. Application of stable carbon isotopes in long term mesocosm studies for carbon cycle investigation

    NASA Astrophysics Data System (ADS)

    Esposito, Mario

    2016-04-01

    Carbon dioxide (CO2) is an effective greenhouse gas. The Oceans absorb ca. 30% of the anthropogenic CO2 emissions and thereby partly attenuate deleterious climate effects. A consequence of the oceanic CO2 uptake is a decreased seawater pH and planktonic community shifts. The quantification of the anthropogenic perturbation was investigated through stable carbon isotope analysis in three "long term" mesocosm experiments (Sweden 2013, Gran Canaria 2014, Norway 2015) which reproduced near natural ecosystem conditions under both controlled and modified future CO2 level (up to 2000 ppm) scenarios. Parallel measurements of the stable isotope composition of dissolved inorganic carbon (δ13CDIC) dissolved organic carbon (δ13CDOC) and particulate carbon (δ13CTPC) both from the mesocosms water column and sediment traps showed similar trends in all the three experiments. A CO2 response was noticeable in the isotopic dataset, but increased CO2 levels had only a subtle effect on the concentrations of the dissolved and particulate organic carbon pool. Distinctive δ13C signatures of the particulate carbon pool both in the water column and the sediments were detectable for the different CO2 treatments and they were strongly correlated with the δ13CDIC signatures but not with the δ13CDOC pool. The validity of the isotopic data was verified by cross-analyses of multiple substances of known isotopic signatures on a GasBench, Elemental Analyser (EA) and on an in-house TOC-IRMS setup for the analysis of δ13CDIC, δ13CTPC and δ13CDOC, respectively. Results from these mesocosm experiments proved the stable carbon isotope approach to be an effective tool for quantifying the uptake and carbon transfer among the various compartments of the marine carbon system.

  10. Advancement and application of gas chromatography isotope ratio mass spectrometry techniques for atmospheric trace gas analysis

    NASA Astrophysics Data System (ADS)

    Giebel, Brian M.

    2011-12-01

    The use of gas chromatography isotope ratio mass spectrometry (GC-IRMS) for compound specific stable isotope analysis is an underutilized technique because of the complexity of the instrumentation and high analytical costs. However stable isotopic data, when coupled with concentration measurements, can provide additional information on a compounds production, transformation, loss, and cycling within the biosphere and atmosphere. A GC-IRMS system was developed to accurately and precisely measure delta13C values for numerous oxygenated volatile organic compounds having natural and anthropogenic sources. The OVOCs include methanol, ethanol, acetone, methyl ethyl ketone, 2-pentanone, and 3-pentanone. Guided by the requirements for analysis of trace components in air, the GC-IRMS system was developed with the goals of increasing sensitivity, reducing dead-volume and peak band broadening, optimizing combustion and water removal, and decreasing the split ratio to the IRMS. The technique relied on a two-stage preconcentration system, a low-volume capillary reactor and water trap, and a balanced reference gas delivery system. Measurements were performed on samples collected from two distinct sources (i.e. biogenic and vehicle emissions) and ambient air collected from downtown Miami and Everglades National Park. However, the instrumentation and the method have the capability to analyze a variety of source and ambient samples. The measured isotopic signatures that were obtained from source and ambient samples provide a new isotopic constraint for atmospheric chemists and can serve as a new way to evaluate their models and budgets for many OVOCs. In almost all cases, OVOCs emitted from fuel combustion were enriched in 13C when compared to the natural emissions of plants. This was particularly true for ethanol gas emitted in vehicle exhaust, which was observed to have a uniquely enriched isotopic signature that was attributed to ethanol's corn origin and use as an alternative

  11. Radioactive isotope production for medical applications using Kharkov electron driven subcritical assembly facility.

    SciTech Connect

    Talamo, A.; Gohar, Y.; Nuclear Engineering Division

    2007-05-15

    Kharkov Institute of Physics and Technology (KIPT) of Ukraine has a plan to construct an accelerator driven subcritical assembly. The main functions of the subcritical assembly are the medical isotope production, neutron thereby, and the support of the Ukraine nuclear industry. Reactor physics experiments and material research will be carried out using the capabilities of this facility. The United States of America and Ukraine have started collaboration activity for developing a conceptual design for this facility with low enrichment uranium (LEU) fuel. Different conceptual designs are being developed based on the facility mission and the engineering requirements including nuclear physics, neutronics, heat transfer, thermal hydraulics, structure, and material issues. Different fuel designs with LEU and reflector materials are considered in the design process. Safety, reliability, and environmental considerations are included in the facility conceptual design. The facility is configured to accommodate future design improvements and upgrades. This report is a part of the Argonne National Laboratory Activity within this collaboration for developing and characterizing the subcritical assembly conceptual design. In this study, the medical isotope production function of the Kharkov facility is defined. First, a review was carried out to identify the medical isotopes and its medical use. Then a preliminary assessment was performed without including the self-shielding effect of the irradiated samples. Finally, more detailed investigation was carried out including the self-shielding effect, which defined the sample size and irradiation location for producing each medical isotope. In the first part, the reaction rates were calculated as the multiplication of the cross section with the unperturbed neutron flux of the facility. Over fifty isotopes were considered and all transmutation channels are used including (n,{gamma}), (n,2n), (n,p), and ({gamma},n). In the second part

  12. High precision delta(17)O isotope measurements of oxygen from silicates and other oxides: method and applications.

    PubMed

    Miller; Franchi; Sexton; Pillinger

    1999-07-01

    The use of infrared laser-assisted fluorination to release oxygen from milligram quantities of silicates or other oxide mineral grains is a well-established technique. However, relatively few studies have reported the optimisation of this procedure for oxygen-17 isotope measurements. We describe here details of an analytical system using infrared (10 µm) laser-assisted fluorination, in conjunction with a dual inlet mass spectrometer of high resolving power ( approximately 250) to provide (17)O and (18)O oxygen isotope measurements from 0.5-2 mg of silicates or other oxide mineral grains. Respective precisions (1) of typically 0.08 and 0.04 per thousand are obtained for the complete analytical procedure. Departures from the mass-dependent oxygen isotope fractionation line are quantified by Delta(17)O; our precision (1) of such measurements on individual samples is shown to be +/-0.024 per thousand. In turn, this permits the offset between parallel, mass-dependent fractionation lines to be characterised to substantially greater precision than has been possible hitherto. Application of this system to investigate the (17)O versus (18)O relationship for numerous terrestrial whole-rock and mineral samples, of diverse geological origins and age, indicates that the complete data set may be described by a single, mass-dependent fractionation line of slope 0.5244+/- 0.00038 (standard error). Copyright 1999 John Wiley & Sons, Ltd.

  13. Future trends in transport and fate of diffuse contaminants in catchments, with special emphasis on stable isotope applications

    USGS Publications Warehouse

    Turner, J.; Albrechtsen, H.-J.; Bonell, M.; Duguet, J.-P.; Harris, B.; Meckenstock, R.; McGuire, K.; Moussa, R.; Peters, N.; Richnow, H.H.; Sherwood-Lollar, B.; Uhlenbrook, S.; van, Lanen H.

    2006-01-01

    A summary is provided of the first of a series of proposed Integrated Science Initiative workshops supported by the UNESCO International Hydrological Programme. The workshop brought together hydrologists, environmental chemists, microbiologists, stable isotope specialists and natural resource managers with the purpose of communicating new ideas on ways to assess microbial degradation processes and reactive transport at catchment scales. The focus was on diffuse contamination at catchment scales and the application of compound-specific isotope analysis (CSIA) in the assessment of biological degradation processes of agrochemicals. Major outcomes were identifying the linkage between water residence time distribution and rates of contaminant degradation, identifying the need for better information on compound specific microbial degradation isotope fractionation factors and the potential of CSIA in identifying key degradative processes. In the natural resource management context, a framework was developed where CSIA techniques were identified as practically unique in their capacity to serve as distributed integrating indicators of process across a range of scales (micro to diffuse) of relevance to the problem of diffuse pollution assessment. Copyright ?? 2006 John Wiley & Sons, Ltd.

  14. 49. Photocopy of photograph (from polaroid snapshot in Burlington Northern ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    49. Photocopy of photograph (from polaroid snapshot in Burlington Northern Railroad correspondence files, 1957) PIER III DAMAGE FROM M/V KORSHOLMA COLLISION - Burlington Northern Railroad Bridge, Spanning Willamette River at River Mile 6.9, Portland, Multnomah County, OR

  15. 47. Photocopy of photograph (from polaroid snapshot in Burlington Northern ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    47. Photocopy of photograph (from polaroid snapshot in Burlington Northern Railroad correspondence files, October, 1957) SHEAR FENCE DAMAGE FROM M/V KORSHOLMA - Burlington Northern Railroad Bridge, Spanning Willamette River at River Mile 6.9, Portland, Multnomah County, OR

  16. Energy Transition Initiative, Island Energy Snapshot - Grenada (Fact Sheet)

    SciTech Connect

    Not Available

    2015-03-01

    This profile provides a snapshot of the energy landscape of Grenada - a small island nation consisting of the island of Grenada and six smaller islands in the southeastern Caribbean Sea - three of which are inhabited: Grenada, Carriacou, and Petite Martinique.

  17. A snapshot of the latest heart failure guidelines.

    PubMed

    Caboral-Stevens, Meriam F

    2014-07-13

    Heart failure (HF) is a complex chronic condition with high morbidity and mortality. The purpose of this article is to present a snapshot of the 2013 ACCF/AHA guidelines focusing on management and treatment of HF in primary care.

  18. Sulfur isotopic analysis of carbonyl sulfide and its application for biogeochemical cycles

    NASA Astrophysics Data System (ADS)

    Hattori, Shohei; Kamezaki, Kazuki; Ogawa, Takahiro; Toyoda, Sakae; Katayama, Yoko; Yoshida, Naohiro

    2016-04-01

    Carbonyl sulfide (OCS or COS) is the most abundant gas containing sulfur in the atmosphere, with an average mixing ratio of 500 p.p.t.v. in the troposphere. OCS is suggested as a sulfur source of the stratospheric sulfate aerosols (SSA) which plays an important role in Earth's radiation budget and ozone depletion. Therefore, OCS budget should be validated for prediction of climate change, but the global OCS budget is imbalance. Recently we developed a promising new analytical method for measuring the stable sulfur isotopic compositions of OCS using nanomole level samples: the direct isotopic analytical technique of on-line gas chromatography-isotope ratio mass spectrometry (GC-IRMS) using fragmentation ions S+ (Hattori et al., 2015). The first measurement of the δ34S value for atmospheric OCS coupled with isotopic fractionation for OCS sink reactions in the stratosphere (Hattori et al., 2011; Schmidt et al., 2012; Hattori et al., 2012) explains the reported δ34S value for background stratospheric sulfate, suggesting that OCS is a potentially important source for background (nonepisodic or nonvolcanic) stratospheric sulfate aerosols. This new method measuring δ34S values of OCS can be used to investigate OCS sources and sinks in the troposphere to better understand its cycle. It is known that some microorganisms in soil can degrade OCS, but the mechanism and the contribution to the OCS in the air are still uncertain. In order to determine sulfur isotopic enrichment factor of OCS during degradation via microorganisms, incubation experiments were conducted using strains belonging to the genera Mycobacterium, Williamsia and Cupriavidus, isolated from natural soil environments (Kato et al., 2008). As a result, sulfur isotope ratios of OCS were increased during degradation of OCS, indicating that reaction for OC32S is faster than that for OC33S and OC34S. OCS degradation via microorganisms is not mass-independent fractionation (MIF) process, suggesting that this

  19. The long-solved problem of the best-fit straight line: Application to isotopic mixing lines

    DOE PAGES

    Wehr, Richard; Saleska, Scott R.

    2017-01-03

    It has been almost 50 years since York published an exact and general solution for the best-fit straight line to independent points with normally distributed errors in both x and y. York's solution is highly cited in the geophysical literature but almost unknown outside of it, so that there has been no ebb in the tide of books and papers wrestling with the problem. Much of the post-1969 literature on straight-line fitting has sown confusion not merely by its content but by its very existence. The optimal least-squares fit is already known; the problem is already solved. Here we introducemore » the non-specialist reader to York's solution and demonstrate its application in the interesting case of the isotopic mixing line, an analytical tool widely used to determine the isotopic signature of trace gas sources for the study of biogeochemical cycles. The most commonly known linear regression methods – ordinary least-squares regression (OLS), geometric mean regression (GMR), and orthogonal distance regression (ODR) – have each been recommended as the best method for fitting isotopic mixing lines. In fact, OLS, GMR, and ODR are all special cases of York's solution that are valid only under particular measurement conditions, and those conditions do not hold in general for isotopic mixing lines. Here, using Monte Carlo simulations, we quantify the biases in OLS, GMR, and ODR under various conditions and show that York's general – and convenient – solution is always the least biased.« less

  20. Carbon Isotopes in Ocean and Land Carbon Cycle Models: Atmospheric Forcing Data and Applications for CMIP6 and Beyond

    NASA Astrophysics Data System (ADS)

    Graven, H. D.; Allison, C. E.; Etheridge, D. M.; Hammer, S.; Keeling, R. F.; Krummel, P. B.; Langenfelds, R. L.; Levin, I.; Rubino, M.; Trudinger, C. M.; Vaughn, B. H.; White, J. W. C.

    2016-12-01

    The carbon isotopic composition of ocean and land carbon reservoirs is influenced by fossil fuel burning, carbon residence time, and fractionation associated with biological and physical processes. Additionally, 14C produced during nuclear weapons testing in the 1950s and 60s has enriched 14C/C ratios in decadally overturning reservoirs. Comparisons of simulated 14C and 13C dynamics between models and with observations can provide insights to key processes in the global carbon cycle including air-sea gas exchange, ocean mixing, terrestrial drought response, and vegetation and soil carbon turnover rates. However, the inclusion of carbon isotopes in large-scale model intercomparisons has so far been limited. One study, the Ocean Carbon Cycle Model Intercomparison Project 2 (OCMIP2), used simulations of ocean 14C to identify biases in model ocean circulation that affect simulated anthropogenic CO2 uptake and marine biogeochemistry. Within the context of CMIP6, we are working to advance the use of carbon isotopes for carbon cycle science, model evaluation and model intercomparison. The variables requested for DECK, OMIP and C4MIP simulations in CMIP6 include stocks and fluxes of 14C and 13C (for models that simulate 14C and 13C). We will present the historical and future atmospheric forcing datasets for Δ14C and δ13C in CO2 that we are making available to modeling groups as part of CMIP6. The historical data uses atmospheric measurements and ice core and tree ring records. For future atmospheric forcing, we use a simple carbon cycle model with CO2 emissions and atmospheric CO2 concentration for different scenarios from ScenarioMIP. We will also describe potential applications for carbon isotope simulations from CMIP6 or other modeling activities. In particular, we will present an evaluation of terrestrial carbon turnover with simulations of bomb-derived 14C inventories in simplified off-line models based on carbon stocks and fluxes in CMIP5 terrestrial models.

  1. Application of sulphur isotope ratios to examine weaning patterns and freshwater fish consumption in Roman Oxfordshire, UK

    NASA Astrophysics Data System (ADS)

    Nehlich, Olaf; Fuller, Benjamin T.; Jay, Mandy; Mora, Alice; Nicholson, Rebecca A.; Smith, Colin I.; Richards, Michael P.

    2011-09-01

    This study investigates the application of sulphur isotope ratios (δ 34S) in combination with carbon (δ 13C) and nitrogen (δ 15N) ratios to understand the influence of environmental sulphur on the isotopic composition of archaeological human and faunal remains from Roman era sites in Oxfordshire, UK. Humans ( n = 83), terrestrial animals ( n = 11), and freshwater fish ( n = 5) were analysed for their isotope values from four locations in the Thames River Valley, and a broad range of δ 34S values were found. The δ 34S values from the terrestrial animals were highly variable (-13.6‰ to +0.5‰), but the δ 34S values of the fish were clustered and 34S-depleted (-20.9‰ to -17.3‰). The results of the faunal remains suggest that riverine sulphur influenced the terrestrial sulphur isotopic signatures. Terrestrial animals were possibly raised on the floodplains of the River Thames, where highly 34S-depleted sulphur influenced the soil. The humans show the largest range of δ 34S values (-18.8‰ to +9.6‰) from any archaeological context to date. No differences in δ 34S values were found between the males (-7.8 ± 6.0‰) and females (-5.3 ± 6.8‰), but the females had a linear correlation ( R2 = 0.71; p < 0.0001) between their δ 15N and δ 34S compositions. These δ 34S results suggest a greater dietary variability for the inhabitants of Roman Oxfordshire than previously thought, with some individuals eating solely terrestrial protein resources and others showing a diet almost exclusively based on freshwater protein such as fish. Such large dietary variability was not visible by analysing only the carbon and nitrogen isotope ratios, and this research represents the largest and most detailed application of δ 34S analysis to examine dietary practices (including breastfeeding and weaning patterns) during the Romano-British Period.

  2. A neutron booster for spallation sources—application to accelerator driven systems and isotope production

    NASA Astrophysics Data System (ADS)

    Galy, J.; Magill, J.; Van Dam, H.; Valko, J.

    2002-06-01

    One can design a critical system with fissile material in the form of a thin layer on the inner surface of a cylindrical neutron moderator such as graphite or beryllium. Recently, we have investigated the properties of critical and near critical systems based on the use of thin actinide layers of uranium, plutonium and americium. The thickness of the required fissile layer depends on the type of fissile material, its concentration in the layer and on the geometrical arrangement, but is typically in the μm-mm range. The resulting total mass of fissile material can be as low as 100 g. Thin fissile layers have a variety of applications in nuclear technology—for example in the design neutron amplifiers for medical applications and "fast" islands in thermal reactors for waste incineration. In the present paper, we investigate the properties of a neutron booster unit for spallation sources and isotope production. In those applications a layer of fissile material surrounds the spallation source. Such a module could be developed for spallation targets foreseen in the MYRRHA (L. Van Den Durpel, H. Aı̈t Abderrahim, P. D'hondt, G. Minsart, J.L. Bellefontaine, S. Bodart, B. Ponsard, F. Vermeersch, W. Wacquier. A prototype accelerator driven system in Belgium: the Myrrha project, Technical Committee Meeting on Feasibility and Motivation for Hybrid concepts for Nuclear Energy generation and Transmutation, Madrid, Spain, September 17-19, 1997 [1]). or MEGAPIE (M. Salvatores, G.S. Bauer, G. Heusener. The MEGAPIE initiative: executive outline and status as per November 1999, MPO-1-GB-6/0_GB, 1999 [2]) projects. With a neutron multiplication factor of the booster unit in the range 10-20 (i.e. with a keff of 0.9-0.95), considerably less powerful accelerators would be required to obtain the desired neutron flux. Instead of the powerful accelerators with proton energies of 1 GeV and currents of 10 mA foreseen for accelerator driven systems, similar neutron fluxes can be obtained

  3. ISOTOPIC BIOGEOCHEMISTRY OF DISSOLVED ORGANIC NITROGEN: A NEW TECHNIQUE AND APPLICATION. (R825151)

    EPA Science Inventory

    We present a new technique for isolating and isotopically characterizing dissolved organic nitrogen (DON) for non-marine waters, 15N values for DON from lacustrine samples and data suggesting that this technique will be a...

  4. Advances in the application of amino acid nitrogen isotopic analysis in ecological and biogeochemical studies

    USDA-ARS?s Scientific Manuscript database

    Compound-specific isotopic analysis of amino acids (CSIA-AA) has emerged in the last decade as a powerful approach for tracing the origins and fate of nitrogen in ecological and biogeochemical studies. This approach is based on the empirical knowledge that source AAs (i.e., phenylalanine), fractiona...

  5. Applications of stable, nonradioactive isotope tracers in in vivo human metabolic research.

    PubMed

    Kim, Il-Young; Suh, Sang-Hoon; Lee, In-Kyu; Wolfe, Robert R

    2016-01-15

    The human body is in a constant state of turnover, that is, being synthesized, broken down and/or converted to different compounds. The dynamic nature of in vivo kinetics of human metabolism at rest and in stressed conditions such as exercise and pathophysiological conditions such as diabetes and cancer can be quantitatively assessed with stable, nonradioactive isotope tracers in conjunction with gas or liquid chromatography mass spectrometry and modeling. Although measurements of metabolite concentrations have been useful as general indicators of one's health status, critical information on in vivo kinetics of metabolites such as rates of production, appearance or disappearance of metabolites are not provided. Over the past decades, stable, nonradioactive isotope tracers have been used to provide information on dynamics of specific metabolites. Stable isotope tracers can be used in conjunction with molecular and cellular biology tools, thereby providing an in-depth dynamic assessment of metabolic changes, as well as simultaneous investigation of the molecular basis for the observed kinetic responses. In this review, we will introduce basic principles of stable isotope methodology for tracing in vivo kinetics of human or animal metabolism with examples of quantifying certain aspects of in vivo kinetics of carbohydrate, lipid and protein metabolism.

  6. The Fe-Isotope System and Its Applicability as a Biosignature

    NASA Technical Reports Server (NTRS)

    Beard, Brian L.; Johnson, Clark M.; Skulan, Joseph; Taylor, Lawerence A.; Sun, Henry; Cox, Lea; Nealson, Kenneth H.; Sinha, Mahadeva P.; Gerdenich, Michael J.

    2001-01-01

    High precision (0.05) Fe isotope analyses show that igneous rocks and loess are invariant but chemical sediments have variable compositions. The relative roles of abiologic and biologic fractionations that produced this range are discussed. Additional information is contained in the original extended abstract.

  7. APPLICATION OF STABLE CARBON AND HYDROGEN ISOTOPIC TECHNIQUES FOR MONITORING BIODEGRADATION OF MTBE IN THE FIELD

    EPA Science Inventory


    A significant challenge in environmental studies is to determine the onset and extent of MTBE bioremediation at an affected site, which may involve indirect approaches such as microcosm verification of microbial activities at a given site. Stable isotopic fractionation is cha...

  8. Applications of stable, nonradioactive isotope tracers in in vivo human metabolic research

    PubMed Central

    Kim, Il-Young; Suh, Sang-Hoon; Lee, In-Kyu; Wolfe, Robert R

    2016-01-01

    The human body is in a constant state of turnover, that is, being synthesized, broken down and/or converted to different compounds. The dynamic nature of in vivo kinetics of human metabolism at rest and in stressed conditions such as exercise and pathophysiological conditions such as diabetes and cancer can be quantitatively assessed with stable, nonradioactive isotope tracers in conjunction with gas or liquid chromatography mass spectrometry and modeling. Although measurements of metabolite concentrations have been useful as general indicators of one's health status, critical information on in vivo kinetics of metabolites such as rates of production, appearance or disappearance of metabolites are not provided. Over the past decades, stable, nonradioactive isotope tracers have been used to provide information on dynamics of specific metabolites. Stable isotope tracers can be used in conjunction with molecular and cellular biology tools, thereby providing an in-depth dynamic assessment of metabolic changes, as well as simultaneous investigation of the molecular basis for the observed kinetic responses. In this review, we will introduce basic principles of stable isotope methodology for tracing in vivo kinetics of human or animal metabolism with examples of quantifying certain aspects of in vivo kinetics of carbohydrate, lipid and protein metabolism. PMID:26795236

  9. Rare isotope accelerator project in Korea and its application to high energy density sciences

    NASA Astrophysics Data System (ADS)

    Chung, M.; Chung, Y. S.; Kim, S. K.; Lee, B. J.; Hoffmann, D. H. H.

    2014-01-01

    As a national science project, the Korean government has recently established the Institute for Basic Science (IBS) with the goal of conducting world-class research in basic sciences. One of the core facilities for the IBS will be the rare isotope accelerator which can produce high-intensity rare isotope beams to investigate the fundamental properties of nature, and also to support a broad research program in material sciences, medical and biosciences, and future nuclear energy technologies. The construction of the accelerator is scheduled to be completed by approximately 2017. The design of the accelerator complex is optimized to deliver high average beam current on targets, and to maximize the production of rare isotope beams through the simultaneous use of Isotope Separation On-Line (ISOL) and In-Flight Fragmentation (IFF) methods. The proposed accelerator is, however, not optimal for high energy density science, which usually requires very high peak currents on the target. In this study, we present possible beam-plasma experiments that can be done within the scope of the current accelerator design, and we also investigate possible future extension paths that may enable high energy density science with intense pulsed heavy ion beams.

  10. ISOTOPIC BIOGEOCHEMISTRY OF DISSOLVED ORGANIC NITROGEN: A NEW TECHNIQUE AND APPLICATION. (R825151)

    EPA Science Inventory

    We present a new technique for isolating and isotopically characterizing dissolved organic nitrogen (DON) for non-marine waters, 15N values for DON from lacustrine samples and data suggesting that this technique will be a...

  11. Application of Hydrogen Isotope Geochemistry to Volcanology: Recent Perspective on Eruption Dynamics

    SciTech Connect

    Nakamura, M.; Kasai, Y.; Sato, N.; Yoshimura, S.

    2008-02-25

    Degassing of magma is central to understand the dynamics of volcanic eruption. Hydrogen isotopic composition of volcanic rocks reflects degassing processes. The natural obsidian samples in some eruptions typically show a gently and then rapidly decreasing {delta}D trends with decreasing water content; this led to the two-stage degassing model, with closed-system volatile exsolution (batch fractionation of hydrogen isotope) during the explosive phase followed by open-system degassing (Rayleigh fractionation) to produce the low {delta}D value of the dome and flow lavas. However, the relationship between pattern of degassing (and fractionation) and mode of eruption is controversial. Based on the CO{sub 2}/H{sub 2}O ratio of the obsidians, Rust et al. suggested that the analyzed samples with relatively constant {delta}D value and high water content were buffered (re-equilibrated) with vapor of relatively constant isotopic composition, assuming that silicic magma along conduit wall is fragmented and highly permeable. However, the timing and mechanism of the shift to open system degassing (Rayleigh fractionation) has not been clarified. To further constrain the eruption dynamics, experimental study on the hydrogen isotope fractionation during degassing would be helpful, although common noble metals used as sample capsules, including Au, are permeable to hydrogen at magmatic temperature, and even to water molecule in the prolonged run, probably due to the change of grain boundary properties such as thermal grooving.

  12. [Principle and application of DNA-based stable isotope probing---a review].

    PubMed

    Jia, Zhongjun

    2011-12-01

    Microbial communities are the engines that drive the global biogeochemical cycle of carbon and nitrogen essential for life on Earth. However, microorganisms have evolved as a result of complex interactions with other organisms and environments. Deciphering the metabolism of microorganisms at the community level in nature will be crucial for a better understanding of the mechanisms that lead to the enormous divergence of microbial ecophysiology. Due to the immense number of uncultivated microbial species and the complexity of microbial communities, delineating community metabolism proves a virtually insurmountable hurdle. By tracing the heavy isotope flow of key elements such as carbon and nitrogen, DNA-based stable isotope probing (DNA-SIP) can provide unequivocal evidence for substrate assimilation by microorganisms in complex environments. The essential prerequisite for a successful DNA-SIP is the identification, with confidence, of isotopically enriched 13C-DNA, of which the amount is generally too low to allow the direct measurement of 13C atom percent of nucleic acid. The methodological considerations for obtaining unambiguous DNA highly enriched in heavy isotope are presented with emphasis on next-generation sequencing technology and metagenomics.

  13. All-diode-laser cooling of Sr+ isotope ions for analytical applications

    NASA Astrophysics Data System (ADS)

    Jung, Kyunghun; Yamamoto, Kazuhiro; Yamamoto, Yuta; Miyabe, Masabumi; Wakaida, Ikuo; Hasegawa, Shuichi

    2017-06-01

    Trapping and cooling of Sr+ isotope ions by an all-diode-laser system has been demonstrated in order to develop a novel mass spectrometric technique in combination with ion trap-laser cooling. First, we constructed external cavity diode lasers and associated stabilization apparatus for laser cooling of Sr+ ions. The transition frequencies confirmed by optogalvanic spectroscopy enabled successful cooling of 88Sr+ ions. An image of two trapped ions has been captured by CCD camera. Minor isotopes, 84Sr+ and 86Sr+, were also cooled and trapped. From an analysis of the observed spectra of a string crystal of each isotope, the isotope shifts of the cooling transition (5s 2S1/2 → 5p 2P1/2) of Sr+ ions were determined to be +371(8) MHz for Δν84-88 and +169(8) MHz for Δν86-88. In the case of the repumping transition (4d 2D3/2 → 5p 2P1/2), Δν84-88 and Δν86-88 were measured to be -833(6) and -400(5) MHz, respectively. These values are in good agreement with previously reported values.

  14. APPLICATION OF STABLE CARBON AND HYDROGEN ISOTOPIC TECHNIQUES FOR MONITORING BIODEGRADATION OF MTBE IN THE FIELD

    EPA Science Inventory


    A significant challenge in environmental studies is to determine the onset and extent of MTBE bioremediation at an affected site, which may involve indirect approaches such as microcosm verification of microbial activities at a given site. Stable isotopic fractionation is cha...

  15. Isotopic Analysis of the Explosive Urea Nitrate and Its Component Ions for Forensic Applications

    NASA Astrophysics Data System (ADS)

    Aranda, R.; Stern, L. A.; McCormick, M. C.; Mothershead, R. F.; Barrow, J. A.

    2008-12-01

    Urea nitrate (UN) is an explosive used in improvised explosive devices. UN (CH5N2O+NO3-) can be synthesized from readily available chemicals and was the main explosive used in the 1993 bombing of the World Trade Center. Isotopic analysis of this explosive has the potential to elucidate the isotopic ratios of the starting materials and geographic information on the location of synthesis. However, depending on the synthesis of the explosive, variable amounts of residual nitric acid may remain, yielding differing contributions of the components to the bulk UN δ15N values. Since δ15N nitrate values cannot be extrapolated from a single component and the bulk value, it is critical to separate the explosive into urea° and potassium nitrate. Therefore, we developed a method to isolate the components of UN for isotopic analysis through the neutralization of urea and separation via methanol washes. The urea in the explosive is neutralized with a 1.1:1 mole ratio of potassium hydroxide:urea in water resulting in urea° and potassium nitrate. The solution is then dried and the urea and potassium nitrate are separated using methanol. Urea and nitrate were isolated from samples of pre-blast UN and the completeness of the extraction was confirmed with a urease assay and a nitrate detection assay on the appropriate components. Isotopic analysis of the isolated urea and potassium nitrate were performed using an EA-IRMS, with the addition of sucrose to the potassium nitrate to aid combustion. For samples of relatively pure UN, the bulk UN δ15N value is stoichiometrically equivalent to the measured δ15N values of the isolated urea and nitrate in a 2:1 ratio. However, some explosive samples contained an excess of nitric acid due to poor preparation. As a result, the bulk UN δ15N values were biased towards the δ15N value of the nitrate. We are conducting experiments to compare the isotopic values of the initial starting reactants in the UN synthesis and the isotopic composition

  16. Barium and Neodymium Isotope Heterogeneities in Early Solar System Materials: Applications to Planetary Reservoir Models

    NASA Astrophysics Data System (ADS)

    Ranen, M. C.; Jacobsen, S. B.

    2005-12-01

    Heavy element isotopic heterogeneities in early Solar System materials may exist as a result of both incomplete mixing of pre-solar nucleosynthetic components in the Solar Nebula leading to different ratios of p-, r- and s-process isotopes in bulk planetary materials as well as heterogeneities caused by the decay of now extinct nuclides. Boyet and Carlson (2005) reported a difference in 142Nd/144Nd between Earths mantle and chondrites of about 20-30 ppm. Assuming that this difference was due to decay of 146Sm and that the Earth and chondrites formed with identical 146Sm/144Sm they inferred the formation of a deep enriched silicate layer (D'' ?) in the Earth that formed within the first 30 Myr of Solar System history. We have obtained a similar difference in 142Nd/144Nd between Earth and chondrites. However, we are now testing their interpretation with Ba isotope measurements of various chondrites. Barium is an ideal element for testing the origin of small isotopic anomalies because it has two isotopes (134 and 136) derived only from the s-process as well as three isotopes (135,137 and 138) derived from both the r- and s-process with 135Ba possibly having a contribution from the decay of now extinct 135Cs. Six chondrites: Allende (CV3), Peace River (L6), Murchison (CM2), Grady (H3.7), Guarena (H6), and Bruderheim (L6) were measured for Ba isotopic composition with a new generation TIMS instrument (a GV ISOPROBE-T). A terrestrial andesite, AGV-1, was also processed for use as our reference standard. Preliminary results indicate widespread heterogeneity in the fractionation corrected 137Ba/136Ba ratio between different meteorites and our terrestrial standard, as high as 25 ppm. Smaller anomalies are also seen in 134Ba/136Ba. These anomalies are likely caused by slight differences in the mixing proportions of r- and s-process Ba in Earth and chondrites. This calls into question whether or not the differences seen in 142Nd/144Nd are truly caused by early differentiation

  17. Quantifying the climatic and topographic controls of precipitation isotopes in continental interiors: applications to unraveling isotopic records of climate in Cenozoic Central Asia

    NASA Astrophysics Data System (ADS)

    Winnick, M. J.; Chamberlain, C. P.; Caves, J. K.; Welker, J. M.

    2014-12-01

    Since the establishment of the IAEA-WMO precipitation-monitoring network in 1961, it has been observed that isotope ratios in precipitation (δ2H and δ18O) generally decrease from coastal to inland locations, an observation described as the continental effect. While discussed frequently in the literature, there have been few attempts to quantify the variables controlling this effect despite the fact that isotopic gradients over continents vary by orders of magnitude. In a number of studies, traditional Rayleigh fractionation has proven inadequate in describing the global variability of isotopic gradients due to its simplified treatment of moisture transport and its lack of moisture recycling through evapotranspiration (ET). We use a one-dimensional idealized model of water vapor transport along a storm track to investigate the dominant variables controlling isotopic gradients in precipitation across terrestrial environments. We find that the sensitivity of these gradients to progressive rainout is controlled primarily by ET with secondary controls exerted by eddy transport. A comparison of modern isotopic gradients within high elevation continental interior regions shows that the effects of seasonal changes in ET are of the same order of magnitude as the effects of rainout due to orographic precipitation. This implies that changing climate and associated changes in ET rates may amplify or completely negate isotopic signals of uplift. We further apply the model to a spatial compilation of Cenozoic isotopic records throughout Central Asia. Over the past 50 Ma, extensive recycling of water via ET has likely masked isotopic signals of the uplift of the northern Tibetan Plateau, Tian Shan, Altai, and Hangay ranges as revealed by complimentary methods of measuring uplift timing and rates. Our results highlight the importance of the coupling between topography, atmospheric circulation, and biological processes in controlling isotopic records of past climate.

  18. Microbial activities and phosphorus cycling: An application of oxygen isotope ratios in phosphate

    NASA Astrophysics Data System (ADS)

    Stout, Lisa M.; Joshi, Sunendra R.; Kana, Todd M.; Jaisi, Deb P.

    2014-08-01

    Microorganisms carry out biochemical transformations of nutrients that make up their cells. Therefore, understanding how these nutrients are transformed or cycled in natural environments requires knowledge of microbial activity. Commonly used indicators for microbial activity typically include determining microbial respiration by O2/CO2 measurements, cell counts, and measurement of enzyme activities. However, coupled studies on nutrient cycling and microbial activity are not given enough emphasis. Here we apply phosphate oxygen isotope ratios (δ18OP) as a tool for measurement of microbial activity and compare the rate of isotope exchange with methods of measuring microbial activities that are more commonly applied in environmental studies including respiration, dehydrogenase activity, alkaline phosphatase activity, and cell counts. Our results show that different bacteria may have different strategies for P uptake, storage and release, their respiration and consequently expression of DHA and APase activities, but in general the trend of their enzyme activities are comparable. Phosphate δ18OP values correlated well with these other parameters used to measure microbial activity with the strongest linear relationships between δ18OP and CO2 evolution (r = -0.99). Even though the rate of isotope exchange for each microorganism used in this study is different, the rate per unit CO2 respiration showed one general trend, where δ18OP values move towards equilibrium while CO2 is generated. While this suggests that P cycling among microorganisms used in this study can be generalized, further research is needed to determine whether the microorganism-specific isotope exchange trend may occur in natural environments. In summary, phosphate oxygen isotope measurements may offer an alternative for use as a tracer to measure microbial activity in soils, sediments, and many other natural environments.

  19. Research and application of method of oxygen isotope of inorganic phosphate in Beijing agricultural soils.

    PubMed

    Tian, Liyan; Guo, Qingjun; Zhu, Yongguan; He, Huijun; Lang, Yunchao; Hu, Jian; Zhang, Han; Wei, Rongfei; Han, Xiaokun; Peters, Marc; Yang, Junxing

    2016-12-01

    Phosphorus (P) in agricultural ecosystems is an essential and limited element for plants and microorganisms. However, environmental problems caused by P accumulation as well as by P loss have become more and more serious. Oxygen isotopes of phosphate can trace the sources, migration, and transformation of P in agricultural soils. In order to use the isotopes of phosphate oxygen, appropriate extraction and purification methods for inorganic phosphate from soils are necessary. Here, we combined two different methods to analyze the oxygen isotopic composition of inorganic phosphate (δ(18)OP) from chemical fertilizers and different fractions (Milli-Q water, 0.5 mol L(-1) NaHCO3 (pH = 8.5), 0.1 mol L(-1) NaOH and 1 mol L(-1) HCl) of agricultural soils from the Beijing area. The δ(18)OP results of the water extracts and NaHCO3 extracts in most samples were close to the calculated equilibrium value. These phenomena can be explained by rapid P cycling in soils and the influence of chemical fertilizers. The δ(18)OP value of the water extracts and NaHCO3 extracts in some soil samples below the equilibrium value may be caused by the hydrolysis of organic P fractions mediated by extracellular enzymes. The δ(18)OP values of the NaOH extracts were above the calculated equilibrium value reflecting the balance state between microbial uptake of phosphate and the release of intracellular phosphate back to the soil. The HCl extracts with the lowest δ(18)OP values and highest phosphate concentrations indicated that the HCl fraction was affected by microbial activity. Hence, these δ(18)Op values likely reflected the oxygen isotopic values of the parent materials. The results suggested that phosphate oxygen isotope analyses could be an effective tool in order to trace phosphate sources, transformation processes, and its utilization by microorganisms in agricultural soils.

  20. Recent applications on isotope ratio measurements by ICP-MS and LA-ICP-MS on biological samples and single particles

    NASA Astrophysics Data System (ADS)

    Becker, J. Sabine; Sela, Hagit; Dobrowolska, Justina; Zoriy, Miroslav; Becker, J. Susanne

    2008-02-01

    Inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation ICP-MS (LA-ICP-MS) have proved themselves to be powerful and sensitive inorganic mass spectrometric techniques for analysing stable and radioactive isotopes in different application fields because of their high sensitivity, low detection limits, good accuracy and precision. New applications of ICP-MS focus on tracer experiments and the development of isotope dilution techniques together with nanoflow injections for the analysis of small volumes of biological samples. Today, LA-ICP-MS is the method of choice for direct determination of metals, e.g., on protein bands in gels after the gel electrophoresis of protein mixtures. Tracer experiments using highly enriched 65Cu were utilized in order to study the formation of metal-binding bovine serum proteins. A challenging task for LA-ICP-MS is its application as an imaging mass spectrometric technique for the production of isotope images (e.gE, from thin sections of brain tissues stained with neodymium). In this paper, we demonstrate the application of imaging mass spectrometry on single particles (zircon and uranium oxide). Single Precambrian zircon crystals from the Baltic Shield were investigated with respect to isotope ratios using LA-ICP-MS for age dating. The U-Pb age was determined from the isochrone with (1.48 ± 0.14) × 109 a. Using isotope ratio measurements on 10 nuclear uranium oxide single particles the 235U/238U isotope ratio was determined to be 0.032 ± 0.004. This paper describes recent developments and applications of isotope ratio measurements by ICP-MS and LA-ICP-MS on biological samples and single particles.

  1. Toward consistent snapshot of the digitized battlefield

    NASA Astrophysics Data System (ADS)

    Sarkar, Susanta P.; Richardson, Paul; Sieh, Larry

    1999-07-01

    A battlefield can be viewed as a collection of entities, enemy and friendly, during combat, each entity scans its surrounding with local sensors to be aware of the current situation. Through digitation of the battlefield, it is possible to share this locally sensed information among all the friendly entities. Significant war-fighting advantages can be realized, if this shared information is consistent. During one of the soldier-in-the-loop simulation exercises invovling ground-based enemy and friendly entities, it was found that achieving consistent snapshot at each friendly node is not a trivial problem. A few contributing factors are: suitable method for combining individual perspective to a global one, mode of communication, movement of all entities, different local perspective of each entity, sensor calibration, fault, and clock synchronization. At the US Army VETRONICS Technology Center, we are in the process of developing a family of algorithms capable of obtaining a consistent global picture invovling one of the critical properties, ground position of entities. In the first stage we have established that for point to point communicating entities, a vector clock based scheme uses fewer number of messages and arrives at the global picture earlier. However, this result does not scale to broadcast situations.

  2. Architectures of Planetary System - Snapshots in Time

    NASA Astrophysics Data System (ADS)

    Montgomery, Michele; Goel, Amit

    2015-08-01

    Architectures of planetary systems are observable snapshots in time, a study of which can aide in our understanding of how planetary systems form and evolve dynamically. For example, if we compare architectures of exoplanetary systems having various stellar host ages with laws that apply to our own Solar System architecture, population, and age, we gain insights into when these laws hold with stellar age and which systems are outliers at various stellar ages. In this work, we study Keplerian motion in confirmed planetary systems as a function of stellar age. Systems eliminated from the study are those with unknown planetary orbital periods, unknown planetary semi-major axis, and/or unknown stellar ages, the latter of which eliminates several Kepler multi-planet systems. As expected, we find Keplerian motion holds for systems that are the age of the Solar System or older, but this result does not seem to hold true for younger systems. In this work we discuss these findings, we identify the outlier systems at various stellar ages from our statistical analysis, and we provide explanations as to why these exo-systems are outliers.

  3. Phosphoryl Transfer Reaction Snapshots in Crystals

    PubMed Central

    Gerlits, Oksana; Tian, Jianhui; Das, Amit; Langan, Paul; Heller, William T.; Kovalevsky, Andrey

    2015-01-01

    To study the catalytic mechanism of phosphorylation catalyzed by cAMP-dependent protein kinase (PKA) a structure of the enzyme-substrate complex representing the Michaelis complex is of specific interest as it can shed light on the structure of the transition state. However, all previous crystal structures of the Michaelis complex mimics of the PKA catalytic subunit (PKAc) were obtained with either peptide inhibitors or ATP analogs. Here we utilized Ca2+ ions and sulfur in place of the nucleophilic oxygen in a 20-residue pseudo-substrate peptide (CP20) and ATP to produce a close mimic of the Michaelis complex. In the ternary reactant complex, the thiol group of Cys-21 of the peptide is facing Asp-166 and the sulfur atom is positioned for an in-line phosphoryl transfer. Replacement of Ca2+ cations with Mg2+ ions resulted in a complex with trapped products of ATP hydrolysis: phosphate ion and ADP. The present structural results in combination with the previously reported structures of the transition state mimic and phosphorylated product complexes complete the snapshots of the phosphoryl transfer reaction by PKAc, providing us with the most thorough picture of the catalytic mechanism to date. PMID:25925954

  4. Application of nitrate and water isotopes to assessment of groundwater quality beneath dairy farms in California

    NASA Astrophysics Data System (ADS)

    Young, M. B.; Harter, T.; Kendall, C.; Silva, S. R.

    2009-12-01

    In California’s Central Valley, nitrate contamination of drinking water wells is a significant concern, and there are multiple potential sources of nitrate in this area including septic discharge, synthetic and manure fertilizers, and concentrated animal feeding operations. Dairies represent the majority of animal feeding operations in California, and have been shown to be potential sources of nitrate, salinity, dissolved organic carbon, and pathogens to groundwater. Within individual dairies, different land use areas including barns and freestalls, corrals, liquid waste lagoons, and fields for forage crops (often fertilized with animal waste, synthetic fertilizer, or both), each of which may have different impacts on the groundwater. In this study, groundwater samples were collected from two dairies in the San Joaquin Valley, where the water table is fairly shallow, and from five dairies in the Tulare Lake Basin, where the water table is much deeper. In each dairy, nitrate isotopes, water isotopes, nutrient concentrations, and other chemical and physical parameters were measured in monitoring wells located within different land use areas of the dairies. Across all sampled dairy wells, δ15N-NO3 ranged from +3.2 to +49.4‰, and δ18O-NO3 ranged from -3.1 to +19.2‰. Mean nitrate concentrations, δ15N-NO3, and δ18O-NO3 were significantly higher in the northern (San Joaquin Valley) dairy wells in comparison to the southern (Tulare Lake Basin) dairy wells. No consistent differences in nitrate isotopic compositions were found between the different land use areas, and large spatial variability in both nitrate concentrations and nitrate isotopic composition was observed within most of the individual dairies. These results emphasize the challenges associated with monitoring groundwater beneath dairies due to high spatial heterogeneity in the aquifer and groundwater constituents. At four of the seven dairies, δ18O and δ2H of the ground water in wells located

  5. A new method and application for determining the nitrogen isotopic composition of NOx

    NASA Astrophysics Data System (ADS)

    Hastings, M. G.; Miller, D. J.; Wojtal, P.; O'Connor, M.

    2015-12-01

    Atmospheric nitrogen oxides (NOx = NO + NO2) play key roles in atmospheric chemistry, air quality, and radiative forcing, and contribute to nitric acid deposition. Sources of NOx include both natural and anthropogenic emissions, which vary significantly in space and time. NOx isotopic signatures offer a potentially valuable tool to trace source impacts on atmospheric chemistry and regional acid deposition. Previous work on NOx isotopic signatures suggests large ranges in values, even from the same emission source, as well as overlapping ranges amongst different sources, making it difficult to use the isotopic composition as a quantitative tracer of source influences. These prior measurements have utilized a variety of methods for collecting the NOx as nitrate or nitrite for isotopic analysis, and testing of some of these methods (including active and passive collections) reveal inconsistencies in efficiency of collection, as well as issues related to changes in conditions such as humidity, temperature, and NOx fluxes. A recently developed method allows for accurately measuring the nitrogen isotopic composition of NOx (NOx = NO + NO2) after capturing the NOx in a potassium permanganate/sodium hydroxide solution as nitrate (Fibiger et al., Anal. Chem., 2014). The method has been thoroughly tested in the laboratory and field, and efficiently collects NO and NO2 under a variety of conditions. There are several advantages to collecting NOx actively, including the ability to collect over minutes to hourly time scales, and the ability to collect in environments with highly variable NOx sources and concentrations. Challenges include a nitrate background present in potassium permanganate (solid and liquid forms), accurately deriving ambient NOx concentrations based upon flow rate and solution concentrations above this variable background, and potential interferences from other nitrogen species. This method was designed to collect NOx in environments with very different

  6. A Snapshot View of High Temperature Superconductivity 2002

    SciTech Connect

    Schuller, Ivan K.; Bansil, Arun; Basov, Dimitri N.

    2002-04-05

    This report outlines the conclusions of a workshop on High Temperature Superconductivity held April 5-8, 2002 in San Diego. The purpose of this report is to outline and highlight some outstanding and interesting issues in the field of High Temperature Superconductivity. The range of activities and new ideas that arose within the context of High Temperature Superconductors is so vast and extensive that it is impossible to summarize it in a brief document. Thus, this report does not pretend to be all-inclusive and cover all areas of activity. It is a restricted snapshot and it only presents a few viewpoints. The complexity and difficulties with high temperature superconductivity are well illustrated by the Buddhist parable of the blind men trying to describe “experimentally” an elephant. These very same facts clearly illustrate that this is an extremely active field, with many unanswered questions, and with a great future potential for discoveries and progress in many (sometimes unpredictable) directions. It is very important to stress that, independently of any current or future applications, this is a very important area of basic research.

  7. Defining a stable water isotope framework for isotope hydrology application in a large trans-boundary watershed (Russian Federation/Ukraine).

    PubMed

    Vystavna, Yuliya; Diadin, Dmytro; Huneau, Frédéric

    2017-07-10

    Stable isotopes of hydrogen ((2)H) and oxygen ((18)O) of the water molecule were used to assess the relationship between precipitation, surface water and groundwater in a large Russia/Ukraine trans-boundary river basin. Precipitation was sampled from November 2013 to February 2015, and surface water and groundwater were sampled during high and low flow in 2014. A local meteoric water line was defined for the Ukrainian part of the basin. The isotopic seasonality in precipitation was evident with depletion in heavy isotopes in November-March and an enrichment in April-October, indicating continental and temperature effects. Surface water was enriched in stable water isotopes from upstream to downstream sites due to progressive evaporation. Stable water isotopes in groundwater indicated that recharge occurs mainly during winter and spring. A one-year data set is probably not sufficient to report the seasonality of groundwater recharge, but this survey can be used to identify the stable water isotopes framework in a weakly gauged basin for further hydrological and geochemical studies.

  8. Second national topical meeting on tritium technology in fission, fusion and isotopic applications

    SciTech Connect

    Anderson, J.L.; Barlit, J.R.

    1985-09-01

    This conference presented information on the following topics: the development of a tritium dispersion code; global environmental transport models for tritium; HT/HTO conversion in mammals; tritium production, releases and population doses at nuclear power reactors; design of tritium processing facilities and equipment for aqueous and gaseous streams; tritium removal from circulating helium by hydriding of rare earth metals; the determination of deuterium and tritium in effluent wastewater by pulsed nuclear magnetic resonance spectroscopy; tritium surface contamination: process calculations for a moderator detritiation plant; recent developments in magnetically coupled vane pumps for tritium service; recovery and storage of tritium by Zr-V-Fe getter; gas handling systems using titanium-sponge and uranium bulk getters; isotope effects and helium retention behavior in vanadium tritide; interaction of hydrogen isotopes with stainless steel 316 L; and the interaction of polyethylene and tritium gas as monitored by Raman spectroscopy.

  9. Augmenting real data with synthetic data: an application in assessing radio-isotope identification algorithms

    SciTech Connect

    Burr, Tom L; Hamada, Michael; Graves, Todd; Myers, Steve

    2008-01-01

    The performance of Radio-Isotope Identification (RIID) algorithms using gamma spectroscopy is increasingly important. For example, sensors at locations that screen for illicit nuclear material rely on isotope identification to resolve innocent nuisance alarms arising from naturally occurring radioactive material. Recent data collections for RIID testing consist of repeat measurements for each of several scenarios to test RIID algorithms. Efficient allocation of measurement resources requires an appropriate number of repeats for each scenario. To help allocate measurement resources in such data collections for RIID algorithm testing, we consider using only a few real repeats per scenario. In order to reduce uncertainty in the estimated RIID algorithm performance for each scenario, the potential merit of augmenting these real repeats with realistic synthetic repeats is also considered. Our results suggest that for the scenarios and algorithms considered, approximately 10 real repeats augmented with simulated repeats will result in an estimate having comparable uncertainty to the estimate based on using 60 real repeats.

  10. Impact of vinasse application in the C and N in the soils cultivaded with sugarcane in South Brasil, using Isotopic Technique

    NASA Astrophysics Data System (ADS)

    Rossete, A. M.; Medeiros, G. G.; Adorno, F. C.; Possignolo, N. V.; Moreira, M. Z.; Camargo, P. B.

    2013-12-01

    The main anthropogenic sources in the environment are fertilizers, pesticides, biomass burning, vehicle emissions, and disposal of urban and industrial waste. Vinasse is characterized as a residual of sugarcane distillery effluent with high concentrations of potassium and organic matter. The environmental impact caused by its use in the vinasse is modification chemical and physical properties in the soil and water. For this, the isotopic technique can be a powerful tool to understand the biogeochemical cycling of light elements (C and N). Some environmental studies have been conducted involving isotopic characterization of Carbon and Nitrogen in soil. Several soils cultivated with sugarcane of different regions of São Paulo state, Brazil, were analyzed to perform the isotopic characterization. The study area was selected where soil management is by mechanical harvesting of sugarcane and vinasse application. The area was divided into three parts: control (without cultivation); after mechanical harvesting of sugarcane; after mechanical harvesting of sugarcane and vinasse application. Three days after the harvest of sugarcane the vinasse was applied and sampling of soil surface was carried out in two periods of 7 and 30 days after application of vinasse. The isotopic determination in the sample soil and concentration of C and N was by IRMS, Thermo Delta Plus, allowing simultaneous determination of 13C/12C isotope ratios (δ13C) and 15N/14N (δ15N). The results of the C and N concentration in the vinasse applied were average values 2.52% and 0.02% and isotopic values of 13C and 15N were -14.1‰ and 5.2‰. The results for the C concentration of the three areas in two periods showed values around 0.86 to 1.01%. The 13C isotopic values were -16.8 to -15.0‰, demonstrating the predominant cultivation in the region in relation to δ13C values of C4 plant (sugarcane). The results of N analysis were 0.08 to 0.10% and 15N isotope analysis, showing values ranging from 7

  11. Isotopes and analogs of hydrogen--from fundamental investigations to practical applications.

    PubMed

    Macrae, Roderick M

    2013-01-01

    Hydrogen has a central role in the story of the universe itself and also in the story of our efforts to understand it. This paper retells the story of the part played by hydrogen and its stable isotope deuterium in the primordial synthesis of the elements, then goes on to describe how the spectrum of atomic hydrogen led to insights into the laws governing matter at the most fundamental level, from the quantum mechanics of Schrödinger and Heisenberg, through quantum electrodynamics, to the most recent work investigating the underlying structure of the proton itself. Atomic hydrogen is unique among the elements in that the concept of isotopy--atoms having the same nuclear charge but different masses--is stretched to its limit in the isotopes of hydrogen, ranging from the well-known isotopes deuterium and tritium to exotic species such as muonium, muonic helium, and positronium. These atoms, or atom-like objects, have much to tell us about fundamental aspects of the universe. In recent years the idea of utilizing hydrogen either as an energy source (through nuclear fusion) or as an energy storage medium (bound in hydrides or other materials) has attracted much attention as a possible avenue to a post-oil energy future. Some of the more interesting recent developments are described here. Dedicated to the memory of Brian C. Webster (1939-2008).

  12. Application of carbon isotope stratigraphy to late miocene shallow marine sediments, new zealand.

    PubMed

    Loutit, T S; Kennett, J P

    1979-06-15

    A distinct (0.5 per mil) carbon-13/carbon-12 isotopic shift in the light direction has been identified in a shallow marine sedimentary sequence of Late Miocene age at Blind River, New Zealand, and correlated with a similar shift in Late Miocene Deep Sea Drilling Project sequences throughout the Indo-Pacific. A dated piston core provides an age for the shift of 6.2 +/- 0.1 million years. Correlations based on the carbon isotopic change require a revision of the previously established magnetostratigraphy at Blind River. The carbon shift at Blind River occurs between 6.2 and 6.3 +/- 0.1 million years before present. A new chronology provides an age for the evolutionary first appearance datum of Globorotalia conomiozea at 6.1 +/- 0.1 million years, the beginning of a distinct latest Miocene cooling event associated with the Kapitean stage at 6.2 +/- 0.1 million years, and the beginning of a distinct shallowing of water depths at 6.1 +/- 0.1 million years. The Miocene-Pliocene boundary as recognized in New Zealand is now dated at 5.3 +/- 0.1 million years. Extension of carbon isotope stratigraphy to other shallow Late Miocene sequences should provide an important datum for international correlation of Late Miocene shallow and deep marine sequences.

  13. Radium isotopes assess water mixing processes and its application in the Zhujiang River estuary

    NASA Astrophysics Data System (ADS)

    Guo, Xiaoyi; Xu, Bochao; Yu, Zhigang; Li, Xiuqin; Nan, Haiming; Jian, Huimin; Jiang, Xueyan; Diao, Shaobo; Gao, Maosheng

    2016-10-01

    Radium (Ra) isotopes are useful for tracing water mass transport and examining estuarine hydrological dynamics. In this study, several hydrological parameters, nutrients, chlorophyll-a (chl-a), suspended particulate matter (SPM) and Ra isotopes (223Ra, 224Ra and 226Ra) of surface waters of the Zhujiang (Pearl) River estuary (ZRE) were measured. This was done for both winter (December) and summer (July) seasons, to quantitatively understand the seasonal characteristics of river plume flow rate and trajectories, as well as the ecological response. The results show that Ra concentrations in summer were higher than in winter, especially 224Ra (about 2-5 times higher). The spatial distribution of three Ra isotopes and relative Ra water ages indicated that river water mainly flushed out of ZRE through the western side in winter, where the water transport was about 5 days faster than in the eastern zone. In summer, diluted river water expended to the east side, resulting in fairly similar water ages for both sides of the river mouth. Although nutrients were higher during the summer season, lower chl-a concentrations indicated that reduced primary production might be caused by high SPM (low light penetration). The results obtained from this study will provide knowledge needed for effectively developing and managing the ZRE.

  14. Radium isotopes assess water mixing processes and its application in the Zhujiang River estuary

    NASA Astrophysics Data System (ADS)

    Guo, Xiaoyi; Xu, Bochao; Yu, Zhigang; Li, Xiuqin; Nan, Haiming; Jian, Huimin; Jiang, Xueyan; Diao, Shaobo; Gao, Maosheng

    2017-09-01

    Radium (Ra) isotopes are useful for tracing water mass transport and examining estuarine hydrological dynamics. In this study, several hydrological parameters, nutrients, chlorophyll- a (chl- a), suspended particulate matter (SPM) and Ra isotopes (223Ra, 224Ra and 226Ra) of surface waters of the Zhujiang (Pearl) River estuary (ZRE) were measured. This was done for both winter (December) and summer (July) seasons, to quantitatively understand the seasonal characteristics of river plume flow rate and trajectories, as well as the ecological response. The results show that Ra concentrations in summer were higher than in winter, especially 224Ra (about 2-5 times higher). The spatial distribution of three Ra isotopes and relative Ra water ages indicated that river water mainly flushed out of ZRE through the western side in winter, where the water transport was about 5 days faster than in the eastern zone. In summer, diluted river water expended to the east side, resulting in fairly similar water ages for both sides of the river mouth. Although nutrients were higher during the summer season, lower chl- a concentrations indicated that reduced primary production might be caused by high SPM (low light penetration). The results obtained from this study will provide knowledge needed for effectively developing and managing the ZRE.

  15. Stable-isotope-labeled carbohydrates and nucleosides: Synthesis and applications in chemistry and biology

    SciTech Connect

    Serianni, A.S.

    1994-12-01

    Carbohydrates play important roles in many key biochemical processes in living cells. For example, they are metabolized to produce energy, mediate cell-cell recognition, and play an indirect role (as constituents of DNA and RNA) in DNA replication, RNA transcription, and protein synthesis. These roles, and others of comparable biochemical significance, have been studied to varying extends with the use of stable isotopically labeled molecules, usually in conjunction with NMR spectroscopy and/or mass spectrometry. For example, carbohydrate metabolism has been monitored in vitro and in vivo with the use of isotopically labeled compounds. Molecular aspects of cell-cell recognition, mediated by cell-surface glycoproteins and glycolipids, have been probed through NMR studies of isotopically labeled oligosaccharides. More recently, the solution behavior of DNA and RNA has been examined through the use of labeled oligonucleotides. In all of these pursuits, the effort and expense to prepare labeled molecules, both of which can be substantial, are more than offset by the wealth of information derived from these studies. This information often cannot be accessed, or can be accessed only with great difficulty, using natural (unlabeled) compounds.

  16. Compound Specific Isotope Analysis (CSIA) for chlorine and bromine: a review of techniques and applications to elucidate environmental sources and processes.

    PubMed

    Cincinelli, Alessandra; Pieri, Francesca; Zhang, Yuan; Seed, Mike; Jones, Kevin C

    2012-10-01

    Chlorinated and brominated compounds belong to the class of organohalogen compounds that have received attention because of their widespread occurrence, use and applications. Understanding the sources and transformation processes of these contaminants in the environment enables assessment of their possible impact on humans and ecosystems. Recently new and innovative methods of Compound Specific Isotope Analysis have started to be applied to characterize the origin and fate of compounds, their breakdown products and degradation rates in different environmental compartments. Almost all studies have focussed on determination of isotopes of C and H, only recently new methodologies have been developed to measure isotopes of Cl and Br. This review firstly gives a brief description of chemistry properties and geochemical cycle of chlorine and bromine followed by a summary of their uses and applications. In the second section, an overview of CSIA techniques and new challenges and successful applications are also presented.

  17. Laser Ablation Molecular Isotopic Spectrometry: Strontium and its isotopes

    NASA Astrophysics Data System (ADS)

    Mao, Xianglei; Bol'shakov, Alexander A.; Choi, Inhee; McKay, Christopher P.; Perry, Dale L.; Sorkhabi, Osman; Russo, Richard E.

    2011-11-01

    The experimental details are reported of Laser Ablation Molecular Isotopic Spectrometry (LAMIS) and its application for performing optical isotopic analysis of solid strontium-containing samples in ambient atmospheric air at normal pressure. The LAMIS detection method is described for strontium isotopes from samples of various chemical and isotopic compositions. The results demonstrate spectrally resolved measurements of the three individual 86Sr, 87Sr, and 88Sr isotopes that are quantified using multivariate calibration of spectra. The observed isotopic shifts are consistent with those calculated theoretically. The measured spectra of diatomic oxide and halides of strontium generated in laser ablation plasmas demonstrate the isotopic resolution and capability of LAMIS. In particular, emission spectra of SrO and SrF molecular radicals provided clean and well resolved spectral signatures for the naturally occurring strontium isotopes. A possibility is discussed of using LAMIS of strontium isotopes for radiogenic age determination.

  18. Determination and application of the equilibrium oxygen isotope effect between water and sulfite

    NASA Astrophysics Data System (ADS)

    Wankel, Scott D.; Bradley, Alexander S.; Eldridge, Daniel L.; Johnston, David T.

    2014-01-01

    The information encoded by the two stable isotope systems in sulfate (δ34SSO4 and δ18OSO4) has been widely applied to aid reconstructions of both modern and ancient environments. Interpretation of δ18OSO4 records has been complicated by rapid oxygen isotope equilibration between sulfoxyanions and water. Specifically, the apparent relationship that develops between δ18OSO4 and δ18Owater during microbial sulfate reduction is thought to result from rapid oxygen isotope equilibrium between intracellular water and aqueous sulfite - a reactive intermediate of the sulfate reduction network that can back-react to produce sulfate. Here, we describe the oxygen equilibrium isotope effect between water and sulfite (referring to all the sum of all S(IV)-oxyanions including sulfite and both isomers and the dimer of bisulfite). Based on experiments conducted over a range of pH (4.5-9.8) and temperature (2-95 °C), where ε = 1000 * (α - 1), we find εSO3-H2O=13.61-0.299∗pH-0.081∗T °C. Thus, at a pH (7.0) and temperature (25 °C) typifying commonly used experimental conditions for sulfate reducing bacterial cultures, sulfite is enriched in 18O by 9.5‰ (±0.8‰) relative to ambient water. We examine the implication of these results in a sulfate reduction network that has been revised to reflect our understanding of the reactions involving oxygen. By evaluating previously published data within this new architecture, our results are consistent with previous suggestions of high reversibility of the sulfate reduction biochemical network. We also demonstrate that intracellular exchange rates between SO32- and water must be on average 1-3 orders of magnitude more rapid than intracellular fluxes of sulfate reduction intermediates and that kinetic isotope effects upstream of SO32- are required to explain previous laboratory and environmental studies of δ18OSO4 resulting as a consequence of sulfate reduction.

  19. A snapshot multispectral imager with integrated tiled filters and optical duplication

    NASA Astrophysics Data System (ADS)

    Geelen, Bert; Tack, Nicolaas; Lambrechts, Andy

    2013-03-01

    Although the potential of spectral imaging has been demonstrated in research environments, its adoption by industry has so far been limited due to the lack of high speed, low cost and compact spectral cameras. We have previously presented work to overcome this limitation by monolithically integrating optical interference filters on top of standard CMOS image sensors for high resolution pushbroom hyperspectral cameras. These cameras require a scanning of the scene and therefore introduce operator complexity due to the need for synchronization and alignment of the scanning to the camera. This typically leads to problems with motion blur, reduced SNR in high speed applications and detection latency and overall restricts the types of applications that can use this system. This paper introduces a novel snapshot multispectral imager concept based on optical filters monolithically integrated on top of a standard CMOS image sensor. By using monolithic integration for the dedicated, high quality spectral filters at its core, it enables the use of mass-produced fore-optics, reducing the total system cost. It overcomes the problems mentioned for scanning applications by snapshot acquisition, where an entire multispectral data cube is sensed at one discrete point in time. This is achieved by applying a novel, tiled filter layout and an optical sub-system which simultaneously duplicates the scene onto each filter tile. Through the use of monolithically integrated optical filters it retains the qualities of compactness, low cost and high acquisition speed, differentiating it from other snapshot spectral cameras based on heterogeneously integrated custom optics. Moreover, thanks to a simple cube assembly process, it enables real-time, low-latency operation. Our prototype camera can acquire multispectral image cubes of 256x256 pixels over 32 bands in the spectral range of 600-1000nm at a speed of about 30 cubes per second at daylight conditions up to 340 cubes per second at higher

  20. Antarctic Seasonality and Living Benthic Foraminiferal Carbon Isotopes: Applications for Assessments of Paleoenvironmental Change

    NASA Astrophysics Data System (ADS)

    Rathburn, A. E.; Martin, J. B.; Ishman, S. E.; Miner, M. R.; Perez, M. E.; Bailey, Z.

    2008-12-01

    As part of the SEASONS project (Seasonal Ecological Analysis of Seafloor Organic Nutrient Supplies), the ecology and carbonate isotopic geochemistry of living benthic foraminifera were examined in cores collected from seven sites in late April and June 2008 from the western Antarctic Peninsula. This region experiences strong seasonality in primary productivity that results in appreciable inter-annual differences in organic flux to the sea floor. Samples were collected across a productivity gradient in the northern Gerlache-southern Bransfield Strait shortly after a surface productivity bloom (late April), and again in the winter (late June). Pore water concentrations were measured on two separate cores from each site for both cruises. Profiles of alkalinity, NH4, and Si, reflect the productivity gradient, with the greatest increase in concentration with depth in the sediment at sites below the most productive zones. At all sites, individual profiles vary slightly within and between cruises, reflecting small scale spatial heterogeneity and differences in diagenesis from high to low productivity time. Most, but not all, sites show elevated pore water concentrations following the bloom. Spatial and vertical distribution patterns of living (Rose Bengal-stained) foraminiferal assemblages (>150 microns) reveal differences in microhabitat preferences for species. These ecological differences are reflected in the carbon isotopic signatures of different species. Carbon isotopic compositions of species occurring at the same site in April and June were compared to assess any seasonal changes resulting from differences in organic input ("Mackensen Effect'). These results provide modern analog information critical to interpreting high-resolution microfossil records of paleoenvironmental change in the Antarctic and elsewhere.

  1. Oxygen isotopes of phosphatic compounds - Application for marine particulate matter, sediments and soils

    USGS Publications Warehouse

    McLaughlin, K.; Paytan, A.; Kendall, C.; Silva, S.

    2006-01-01

    The phosphate oxygen isotopic composition in naturally occurring particulate phosphatic compounds (??18Op) can be used as a tracer for phosphate sources and to evaluate the cycling of phosphorus (P) in the environment. However, phosphatic compounds must be converted to silver phosphate prior to isotopic analysis, a process that involves digestion of particulate matter in acid. This digestion will hydrolyze some of the phosphatic compounds such that oxygen from the acid solution will be incorporated into the sample as these phosphatic compounds are converted to orthophosphate (PO 43-). To determine the extent of incorporation of reagent oxygen into the sample, we digested various phosphatic compounds in both acid amended with H218O (spiked) and unspiked acid and then converted the samples to silver phosphate for ??18Op analysis. Our results indicate that there is no isotopic fractionation associated with acid digestion at 50??C. Furthermore, we found that reagent oxygen incorporation is a function of the oxygen to phosphorus ratio (O:P) of the digested compound whereby the percentage of reagent oxygen incorporated into the sample is the same as that which is required to convert all of the P-compounds into orthophosphate. Based on these results, we developed a correction for reagent oxygen incorporation using simple mass balance, a procedure that allows for the determination of the ??18O p of samples containing a mixture of phosphatic compounds. We analyzed a variety of environmental samples for ??18O p to demonstrate the utility of this approach for understanding sources and cycling of P. ?? 2005 Elsevier B.V. All rights reserved.

  2. Strontium isotopic signatures of oil-field waters: Applications for reservoir characterization

    USGS Publications Warehouse

    Barnaby, R.J.; Oetting, G.C.; Gao, G.

    2004-01-01

    The 87Sr/86Sr compositions of formation waters that were collected from 71 wells producing from a Pennsylvanian carbonate reservoir in New Mexico display a well-defined distribution, with radiogenic waters (up to 0.710129) at the updip western part of the reservoir, grading downdip to less radiogenic waters (as low as 0.708903 to the east. Salinity (2800-50,000 mg/L) displays a parallel trend; saline waters to the west pass downdip to brackish waters. Elemental and isotopic data indicate that the waters originated as meteoric precipitation and acquired their salinity and radiogenic 87Sr through dissolution of Upper Permian evaporites. These meteoric-derived waters descended, perhaps along deeply penetrating faults, driven by gravity and density, to depths of more than 7000 ft (2100 m). The 87 Sr/86Sr and salinity trends record influx of these waters along the western field margin and downdip flow across the field, consistent with the strong water drive, potentiometric gradient, and tilted gas-oil-water contacts. The formation water 87Sr/86Sr composition can be useful to evaluate subsurface flow and reservoir behavior, especially in immature fields with scarce pressure and production data. In mature reservoirs, Sr Sr isotopes can be used to differentiate original formation water from injected water for waterflood surveillance. Strontium isotopes thus provide a valuable tool for both static and dynamic reservoir characterization in conjunction with conventional studies using seismic, log, core, engineering, and production data. Copyright ??2004. The American Association of Petroleum Geologist. All rights reserved.

  3. Anomalous gain in an isotopically mixed CO2 laser and application to absolute wavelength calibration

    NASA Technical Reports Server (NTRS)

    Hewagama, Tilak; Oppenheim, Uri P.; Mumma, Michael J.

    1991-01-01

    Measurements are reported on a grating-tuned CO2 laser, containing an isotropic mixture of O-16C-12O-16, O-16C-12O-18, and O-18C-12O-18. The P6 and R14 lines of O-16C-12O-16 were found to have anomalously high intensities. These anomalies are produced by the near coincidence of the transition frequencies in two distinct isotopes, permitting them to act as a single indistinguishable population. These two lines can be used to identify the rotational quantum numbers in the P and R branch spectra, thereby permitting absolute wavelength calibration to be achieved.

  4. Applications of Structural Mass Spectrometry to Metabolomics: Clarifying Bond Specific Spectral Signatures with Isotope Edited Spectroscopy

    NASA Astrophysics Data System (ADS)

    Gorlova, Olga; Wolke, Conrad T.; Fournier, Joseph; Colvin, Sean; Johnson, Mark; Miller, Scott

    2015-06-01

    Comprehensive FTIR, MS/MS and NMR of pharmaceuticals are generally readily available but characterization of their metabolites has been an obstacle. Atorvastatin is a statin drug responsible for the maintenance of cholesterol in the body. Diovan is an angiostensin receptor antagonist used to treat high blood pressure and congestive heart failure. The field of metabolomics, however, is struggling to obtain the identity of their structures. We implement mass spectrometry with cryogenic ion spectroscopy to study gaseous ions of the desired metabolites which, in combination, not only identify the mass of the metabolite but also elucidate their structures through isotope-specific infrared spectroscopy.

  5. Comparison of dynamic isotope power systems for distributed planet surface applications

    NASA Technical Reports Server (NTRS)

    Bents, David J.; Mckissock, Barbara I.; Hanlon, James C.; Schmitz, Paul C.; Rodriguez, Carlos D.; Withrow, Colleen A.

    1991-01-01

    Dynamic isotope power system (DIPS) alternatives were investigated and characterized for the surface mission elements associated with a lunar base and subsequent manned Mars expedition. System designs based on two convertor types were studied. These systems were characterized parametrically and compared over the steady-state electrical output power range 0.2 to 20 kWe. Three methods of thermally integrating the heat source and the Stirling heater head were considered, depending on unit size. Figures of merit were derived from the characterizations and compared over the parametric range. Design impacts of mission environmental factors are discussed and quantitatively assessed.

  6. Application of tree-ring isotopic analyses to reconstruct historical water use of riparian trees.

    PubMed

    Alstad, Karrin P; Hart, Stephen C; Horton, Jonathan L; Kolb, Thomas E

    2008-03-01

    Historical patterns of water source use by trees inferred from long-term records of tree-ring stable isotopic content could assist in evaluating the impact of human alterations to natural stream flow regimes (e.g., water impoundments, stream flow diversions, and groundwater extraction). Our objective was to assess the utility of the hydrogen stable isotopic composition (SD) of tree rings as an index of historical water source use by riparian trees. We investigated the influence of site conditions that varied in climate and hydrology on the relationship between deltaD of Populus xylem water (deltaD(xyl)) and tree-ring cellulose (deltaD(cell)). deltaD(xyl) and deltaD(cell) were strongly correlated across sites (r2 = 0.89). However, the slope of this relationship was less than 1, indicating that factors other than deltaD(xyl) influenced deltaD(cell). Inverse modeling with an isotopic fractionation model for tree-ring cellulose suggested that the lack of one-to-one correspondence between deltaD(xyl) and deltaD(cell) was due to the influence of the hydrogen isotopic content of the atmospheric water vapor (deltaD(atm)). Empirically measured values of deltaD(cell) were typically within the seasonal range of deltaD(cell) predicted from the fractionation model. Sensitivity analyses showed that changes in deltaD(xyl) generally had a greater influence at high-elevation montane sites, whereas deltaD(xyl) and deltaD(atm) had about equal influence on deltaD(cell) at low-elevation desert sites. The intrasite relationship between deltaD(cell) and deltaD(xyl) among individual trees was poor, perhaps because of the within-site spatial variation in hydrologic conditions and associated tree physiological responses. Our study suggests that historical variation in deltaD(cell) of Populus provides information on historical variation in both time-integrated water source use and atmospheric conditions; and that the influence of atmospheric conditions is not consistent over sites with large

  7. Application of the generator coordinate method to neutron-rich Se and Ge isotopes

    NASA Astrophysics Data System (ADS)

    Higashiyama, Koji; Yoshinaga, Naotaka

    2014-03-01

    The quantum-number projected generator coordinate method (GCM) is applied to the neutron-rich Se and Ge isotopes, where the monopole and quadrupole pairing plus quadrupole-quadrupole interaction is employed as an effective interaction. The energy spectra obtained by the GCM are compared to both the shell model results and the experimental data. The GCM reproduces well the energy levels of high-spin states as well as the low-lying states. The structure of the low-lying collective states is analyzed through the GCM wave functions.

  8. Application of Screening Experimental Designs to Assess Chromatographic Isotope Effect upon Isotope-Coded Derivatization for Quantitative Liquid Chromatography–Mass Spectrometry

    PubMed Central

    2015-01-01

    Isotope effect may cause partial chromatographic separation of labeled (heavy) and unlabeled (light) isotopologue pairs. Together with a simultaneous matrix effect, this could lead to unacceptable accuracy in quantitative liquid chromatography–mass spectrometry assays, especially when electrospray ionization is used. Four biologically relevant reactive aldehydes (acrolein, malondialdehyde, 4-hydroxy-2-nonenal, and 4-oxo-2-nonenal) were derivatized with light or heavy (d3-, 13C6-, 15N2-, or 15N4-labeled) 2,4-dinitrophenylhydrazine and used as model compounds to evaluate chromatographic isotope effects. For comprehensive assessment of retention time differences between light/heavy pairs under various gradient reversed-phase liquid chromatography conditions, major chromatographic parameters (stationary phase, mobile phase pH, temperature, organic solvent, and gradient slope) and different isotope labelings were addressed by multiple-factor screening using experimental designs that included both asymmetrical (Addelman) and Plackett–Burman schemes followed by statistical evaluations. Results confirmed that the most effective approach to avoid chromatographic isotope effect is the use of 15N or 13C labeling instead of deuterium labeling, while chromatographic parameters had no general influence. Comparison of the alternate isotope-coded derivatization assay (AIDA) using deuterium versus 15N labeling gave unacceptable differences (>15%) upon quantifying some of the model aldehydes from biological matrixes. On the basis of our results, we recommend the modification of the AIDA protocol by replacing d3-2,4-dinitrophenylhydrazine with 15N- or 13C-labeled derivatizing reagent to avoid possible unfavorable consequences of chromatographic isotope effects. PMID:24922593

  9. Assessing dissolved organic matter dynamics and source strengths in a subtropical estuary: Application of stable carbon isotopes and optical properties

    NASA Astrophysics Data System (ADS)

    Ya, Chao; Anderson, William; Jaffé, Rudolf

    2015-01-01

    The dynamics of dissolved organic matter (DOM) in subtropical coastal bays are complex. For example, variations in DOM characteristics and sources in Florida Bay are believed to be mainly driven by both hydrology and associated runoff of terrestrial DOM, and by primary productivity mostly from seagrass sources. However, confirmation and quantification of different DOM sources are still incomplete and needed for carbon budget assessments. Optical parameters based on excitation emission matrix fluorescence coupled with parallel factor analysis (EEM-PARAFAC) that had previously been tentatively assigned to both terrestrial and seasgrass sources. These correlated linearly with determined δ13C values, confirming an allochthonous, hydrologically-driven terrestrial source for the humic-like fluorescent components, while autochthonous DOM reflected by the protein-like fluorescence is mainly derived through primary productivity of seagrass communities. This study demonstrated the feasibility of combining optical signatures and stable isotopes in advancing the understanding of DOM dynamics in estuarine systems. Using stable carbon isotopic signatures of DOM, and applying a simple two end-member mixing model, the relative contributions of these two sources to the DOM pool in the bay were estimated. Results indicate that the highest proportion of DOM (ca. 72%) during the dry season was seagrass-derived, but clear variations were observed on both spatial and temporal scales. Limitations to the application of optical properties for the quantitative estimation of DOM sources in such coastal systems are discussed.

  10. Synthesis of l-cysteine derivatives containing stable sulfur isotopes and application of this synthesis to reactive sulfur metabolome.

    PubMed

    Ono, Katsuhiko; Jung, Minkyung; Zhang, Tianli; Tsutsuki, Hiroyasu; Sezaki, Hiroshi; Ihara, Hideshi; Wei, Fan-Yan; Tomizawa, Kazuhito; Akaike, Takaaki; Sawa, Tomohiro

    2017-05-01

    Cysteine persulfide is an L-cysteine derivative having one additional sulfur atom bound to a cysteinyl thiol group, and it serves as a reactive sulfur species that regulates redox homeostasis in cells. Here, we describe a rapid and efficient method of synthesis of L-cysteine derivatives containing isotopic sulfur atoms and application of this method to a reactive sulfur metabolome. We used bacterial cysteine syntheses to incorporate isotopic sulfur atoms into the sulfhydryl moiety of L-cysteine. We cloned three cysteine synthases-CysE, CysK, and CysM-from the Gram-negative bacterium Salmonella enterica serovar Typhimurium LT2, and we generated their recombinant enzymes. We synthesized (34)S-labeled L-cysteine from O-acetyl-L-serine and (34)S-labeled sodium sulfide as substrates for the CysK or CysM reactions. Isotopic labeling of L-cysteine at both sulfur ((34)S) and nitrogen ((15)N) atoms was also achieved by performing enzyme reactions with (15)N-labeled L-serine, acetyl-CoA, and (34)S-labeled sodium sulfide in the presence of CysE and CysK. The present enzyme systems can be applied to syntheses of a series of L-cysteine derivatives including L-cystine, L-cystine persulfide, S-sulfo-L-cysteine, L-cysteine sulfonate, and L-selenocystine. We also prepared (34)S-labeled N-acetyl-L-cysteine (NAC) by incubating (34)S-labeled L-cysteine with acetyl coenzyme A in test tubes. Tandem mass spectrometric identification of low-molecular-weight thiols after monobromobimane derivatization revealed the endogenous occurrence of NAC in the cultured mammalian cells such as HeLa cells and J774.1 cells. Furthermore, we successfully demonstrated, by using (34)S-labeled NAC, metabolic conversion of NAC to glutathione and its persulfide, via intermediate formation of L-cysteine, in the cells. The approach using isotopic sulfur labeling combined with mass spectrometry may thus contribute to greater understanding of reactive sulfur metabolome and redox biology. Copyright © 2017 Elsevier

  11. Isotopic Biogeochemistry

    NASA Technical Reports Server (NTRS)

    Hayes, J. M.

    1985-01-01

    An overview is provided of the biogeochemical research. The funding, productivity, personnel and facilities are reviewed. Some of the technical areas covered are: carbon isotopic records; isotopic studies of banded iron formations; isotope effects in microbial systems; studies of organic compounds in ancient sediments; and development in isotopic geochemistry and analysis.

  12. Maximum bandwidth snapshot channeled imaging polarimeter with polarization gratings

    NASA Astrophysics Data System (ADS)

    LaCasse, Charles F.; Redman, Brian J.; Kudenov, Michael W.; Craven, Julia M.

    2016-05-01

    Compact snapshot imaging polarimeters have been demonstrated in literature to provide Stokes parameter estimations for spatially varying scenes using polarization gratings. However, the demonstrated system does not employ aggressive modulation frequencies to take full advantage of the bandwidth available to the focal plane array. A snapshot imaging Stokes polarimeter is described and demonstrated through results. The simulation studies the challenges of using a maximum bandwidth configuration for a snapshot polarization grating based polarimeter, such as the fringe contrast attenuation that results from higher modulation frequencies. Similar simulation results are generated and compared for a microgrid polarimeter. Microgrid polarimeters are instruments where pixelated polarizers are superimposed onto a focal plan array, and this is another type of spatially modulated polarimeter, and the most common design uses a 2x2 super pixel of polarizers which maximally uses the available bandwidth of the focal plane array.

  13. Chemical and Sr isotopic characterization of North America uranium ores: Nuclear forensic applications

    SciTech Connect

    Balboni, Enrica; Jones, Nina; Spano, Tyler; Simonetti, Antonio; Burns, Peter C.

    2016-08-31

    This study reports major, minor, and trace element data and Sr isotope ratios for 11 uranium ore (uraninite, UO2+x) samples and one processed uranium ore concentrate (UOC) from various U.S. deposits. The uraninite investigated represent ores formed via different modes of mineralization (e.g., high- and low-temperature) and within various geological contexts, which include magmatic pegmatites, metamorphic rocks, sandstone-hosted, and roll front deposits. In situ trace element data obtained by laser ablation-ICP-MS and bulk sample Sr isotopic ratios for uraninite samples investigated here indicate distinct signatures that are highly dependent on the mode of mineralization and host rock geology. Relative to their high-temperature counterparts, low-temperature uranium ores record high U/Th ratios (>1000), low total rare earth element (REE) abundances (<1 wt%), high contents (>300 ppm) of first row transition metals (Sc, Ti, V, Cr, Mn, Co, Ni), and radiogenic 87Sr/86Sr ratios (>0.7200). Comparison of chondrite normalized REE patterns between uraninite and corresponding processed UOC from the same locality indicates identical patterns at different absolute concentrations. Lastly, this result ultimately confirms the importance of establishing geochemical signatures of raw, uranium ore materials for attribution purposes in the forensic analysis of intercepted nuclear materials.

  14. Chemical and Sr isotopic characterization of North America uranium ores: Nuclear forensic applications

    DOE PAGES

    Balboni, Enrica; Jones, Nina; Spano, Tyler; ...

    2016-08-31

    This study reports major, minor, and trace element data and Sr isotope ratios for 11 uranium ore (uraninite, UO2+x) samples and one processed uranium ore concentrate (UOC) from various U.S. deposits. The uraninite investigated represent ores formed via different modes of mineralization (e.g., high- and low-temperature) and within various geological contexts, which include magmatic pegmatites, metamorphic rocks, sandstone-hosted, and roll front deposits. In situ trace element data obtained by laser ablation-ICP-MS and bulk sample Sr isotopic ratios for uraninite samples investigated here indicate distinct signatures that are highly dependent on the mode of mineralization and host rock geology. Relative tomore » their high-temperature counterparts, low-temperature uranium ores record high U/Th ratios (>1000), low total rare earth element (REE) abundances (<1 wt%), high contents (>300 ppm) of first row transition metals (Sc, Ti, V, Cr, Mn, Co, Ni), and radiogenic 87Sr/86Sr ratios (>0.7200). Comparison of chondrite normalized REE patterns between uraninite and corresponding processed UOC from the same locality indicates identical patterns at different absolute concentrations. Lastly, this result ultimately confirms the importance of establishing geochemical signatures of raw, uranium ore materials for attribution purposes in the forensic analysis of intercepted nuclear materials.« less

  15. ZoomQuant: an application for the quantitation of stable isotope labeled peptides.

    PubMed

    Halligan, Brian D; Slyper, Ronit Y; Twigger, Simon N; Hicks, Wayne; Olivier, Michael; Greene, Andrew S

    2005-03-01

    The main goal of comparative proteomics is the quantitation of the differences in abundance of many proteins between two different biological samples in a single experiment. By differentially labeling the peptides from the two samples and combining them in a single analysis, relative ratios of protein abundance can be accurately determined. Protease catalyzed (18)O exchange is a simple method to differentially label peptides, but the lack of robust software tools to analyze the data from mass spectra of (18)O labeled peptides generated by common ion trap mass spectrometers has been a limitation. ZoomQuant is a stand-alone computational tool that analyzes the mass spectra of (18)O labeled peptides from ion trap instruments and determines relative abundance ratios between two samples. Starting with a filtered list of candidate peptides that have been successfully identified by Sequest, ZoomQuant analyzes the isotopic forms of the peptides using high-resolution zoom scan spectrum data. The theoretical isotope distribution is determined from the peptide sequence and is used to deconvolute the peak areas associated with the unlabeled, partially labeled, and fully labeled species. The ratio between the labeled and unlabeled peptides is then calculated using several different methods. ZoomQuant's graphical user interface allows the user to view and adjust the parameters for peak calling and quantitation and select which peptides should contribute to the overall abundance ratio calculation. Finally, ZoomQuant generates a summary report of the relative abundance of the peptides identified in the two samples.

  16. Application of multielement stable isotope ratio analysis to the characterization of French, italian, and spanish cheeses.

    PubMed

    Camin, Federica; Wietzerbin, Karine; Cortes, Anaisabel Blanch; Haberhauer, Georg; Lees, Michéle; Versini, Giuseppe

    2004-10-20

    The stable isotope ratios (delta13C, delta15N, and delta34S of casein and delta13C and delta18O of glycerol) measured by IRMS of French, Italian, and Spanish cheeses are presented and discussed. Variability factors such as animal-feeding regimen, geographical origin, and climatic and seasonal conditions were studied to check the possibilities of cheese characterization offered by each isotopic parameter. Delta13C values of both casein and glycerol appeared to be strongly correlated to the amount of maize in the animal diet. Delta15N and delta34S of casein proved to be mostly influenced by the geoclimatic conditions of the area (aridity, closeness to the sea, altitude). Delta18O of glycerol was more dependent on the geographical origin of the cheeses and on climatic/seasonal parameters. By applying a multivariate stepwise canonical discriminant analysis, good discrimination possibilities for the different European cheeses were obtained, confirmed by the classification analysis, when >90% of the samples were correctly reclassified. Copyright 2004 American Chemical Society

  17. Chemical and Sr isotopic characterization of North America uranium ores: Nuclear forensic applications

    SciTech Connect

    Balboni, Enrica; Jones, Nina; Spano, Tyler; Simonetti, Antonio; Burns, Peter C.

    2016-08-31

    This study reports major, minor, and trace element data and Sr isotope ratios for 11 uranium ore (uraninite, UO2+x) samples and one processed uranium ore concentrate (UOC) from various U.S. deposits. The uraninite investigated represent ores formed via different modes of mineralization (e.g., high- and low-temperature) and within various geological contexts, which include magmatic pegmatites, metamorphic rocks, sandstone-hosted, and roll front deposits. In situ trace element data obtained by laser ablation-ICP-MS and bulk sample Sr isotopic ratios for uraninite samples investigated here indicate distinct signatures that are highly dependent on the mode of mineralization and host rock geology. Relative to their high-temperature counterparts, low-temperature uranium ores record high U/Th ratios (>1000), low total rare earth element (REE) abundances (<1 wt%), high contents (>300 ppm) of first row transition metals (Sc, Ti, V, Cr, Mn, Co, Ni), and radiogenic 87Sr/86Sr ratios (>0.7200). Comparison of chondrite normalized REE patterns between uraninite and corresponding processed UOC from the same locality indicates identical patterns at different absolute concentrations. Lastly, this result ultimately confirms the importance of establishing geochemical signatures of raw, uranium ore materials for attribution purposes in the forensic analysis of intercepted nuclear materials.

  18. Application of stable carbon isotope analysis to the detection of testosterone administration to cattle.

    PubMed

    Hebestreit, Moritz; Flenker, Ulrich; Buisson, Corinne; Andre, Francois; Le Bizec, Bruno; Fry, Hildburg; Lang, Melanie; Weigert, Angelika Preiss; Heinrich, Katharina; Hird, Simon; Schänzer, Wilhelm

    2006-04-19

    The use of anabolic substances is prohibited in food-producing animals throughout the European Union. No method is available to reliably detect the misuse of natural hormones in cattle. A method was developed to detect the abuse of testosterone in cattle fattening. Synthesized testosterone is rather depleted in the (13)C/(12)C ratio. Hence, the method is based on gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) analysis of urine. To select testosterone metabolites and endogenous reference compounds (ERC), the concentration of urinary steroids of cattle was investigated. Dehydroepiandrosterone and androst-5ene-3beta,17alpha-diol were chosen as ERCs to show endogenous (13)C/(12)C ratios. Etiocholanolone and 5alpha-androstane-3beta,17alpha-diol were chosen as the most important testosterone metabolites. Other metabolites known from literature like epitestosterone were less promising. In principle, GC/C/IRMS is a nonspecific method because finally carbon dioxide is analyzed. Therefore, a dedicated cleanup procedure for the selected steroids was developed. By means of proposed confidence intervals in the isotopic composition of ERCs and metabolites, the administration of testosterone to cattle could be detected reliably. Differences of up to 11 per thousand on the delta-scale between ERC and testosterone metabolites were found after testosterone administration, whereas endogenous differences did not exceed 2 per thousand.

  19. Isotopic separation

    SciTech Connect

    Chen, C.

    1981-03-10

    Method and apparatus for separating isotopes in an isotopic mixture of atoms or molecules by increasing the mass differential among isotopic species. The mixture containing a particular isotope is selectively irradiated so as to selectively excite the isotope. This preferentially excited species is then reacted rapidly with an additional preselected radiation, an electron or another chemical species so as to form a product containing the specific isotope, but having a mass different than the original species initially containing the particular isotope. The product and the remaining balance of the mixture is then caused to flow through a device which separates the product from the mixture based upon the increased mass differential.

  20. Design of a miniature SWIR hyperspectral snapshot imager utilizing multivariate optical elements

    NASA Astrophysics Data System (ADS)

    Priore, Ryan; Dougherty, John; Cohen, Omer; Bikov, Leonid; Hirsh, Itay

    2016-10-01

    CIRTEMO, SCD and Pixelteq have co-developed a miniature short-wave infrared (SWIR) hyperspectral snapshot imager utilizing Multivariate Optical Elements (MOEs). The resultant product may address many of the detection challenges facing multiple markets including commercial, medical, security and defense. This paper highlights the design process of developing MOEs for a targeted application, as well as the technological challenges faced and solutions developed for successful integration of a micro-patterned mosaic array to an InGaAs focal plane array.

  1. Visual Snapshots of Intracellular Kinase Activity At The Onset of Mitosis

    PubMed Central

    Dai, Zhaohua; Dulyaninova, Natalya G.; Kumar, Sanjai; Bresnick, Anne R.; Lawrence, David S.

    2007-01-01

    Summary Visual snapshots of intracellular kinase activity can be acquired with exquisite temporal control using a light-activatable (caged) sensor, thereby providing a means to interrogate enzymatic activity at any point during the cell division cycle. Robust protein kinase activity transpires just prior to, but not immediately following, nuclear envelope breakdown (NEB). Furthermore, kinase activity is required for progression from prophase into metaphase. Finally, the application of selective protein kinase C (PKC) inhibitors, in combination with the caged sensor, correlates the action of the PKC β isoform with subsequent NEB. PMID:18022564

  2. Video Snapshots: Creating High-Quality Images from Video Clips.

    PubMed

    Sunkavalli, Kalyan; Joshi, Neel; Kang, Sing Bing; Cohen, Michael F; Pfister, Hanspeter

    2012-11-01

    We describe a unified framework for generating a single high-quality still image ("snapshot") from a short video clip. Our system allows the user to specify the desired operations for creating the output image, such as super resolution, noise and blur reduction, and selection of best focus. It also provides a visual summary of activity in the video by incorporating saliency-based objectives in the snapshot formation process. We show examples on a number of different video clips to illustrate the utility and flexibility of our system.

  3. Snapshot spectral and polarimetric imaging; target identification with multispectral video

    NASA Astrophysics Data System (ADS)

    Bartlett, Brent D.; Rodriguez, Mikel D.

    2013-05-01

    As the number of pixels continue to grow in consumer and scientific imaging devices, it has become feasible to collect the incident light field. In this paper, an imaging device developed around light field imaging is used to collect multispectral and polarimetric imagery in a snapshot fashion. The sensor is described and a video data set is shown highlighting the advantage of snapshot spectral imaging. Several novel computer vision approaches are applied to the video cubes to perform scene characterization and target identification. It is shown how the addition of spectral and polarimetric data to the video stream allows for multi-target identification and tracking not possible with traditional RGB video collection.

  4. Hydrogen-isotope transport in an ELBRODUR G CuCrZr alloy for nuclear applications in heat sinks

    NASA Astrophysics Data System (ADS)

    Noh, S. J.; Byeon, W. J.; Shin, H. W.; Kim, H. S.; Kim, Jaeyong; Lee, S. K.; Kim, Jaewoo

    2016-05-01

    We present the first complete data set of the transport parameters (permeability, diffusivity, and solubility) of hydrogen and deuterium in an ELBRODUR G precipitation hardened CuCrZr alloy experimentally measured by using the time-dependent gas-phase technique in an elevated temperature range of 300-600 °C for nuclear applications in heat sinks. Using the measured values for hydrogen and deuterium and a quantum mechanical model based on a harmonic approximation, an extrapolation for tritium is also presented. The isotope effect ratios for the transport parameters were also estimated. Furthermore, our hydrogen results for ELBRODUR G were compared with the results for other copper alloys previously reported by other authors.

  5. Continuous measurements of water vapor isotopic compositions using an integrated cavity output spectrometer: calibrations and applications

    NASA Astrophysics Data System (ADS)

    Wang, L.; Caylor, K.; Dragoni, D.

    2009-04-01

    The 18O and 2H of water vapor can be used to investigate couplings between biological processes (e.g., photosynthesis or transpiration) and hydrologic processes (e.g., evaporation) and therefore serve as powerful tracers in hydrological cycles. A typical method for determining δ18O and δ2H fluxes in landscapes is a "Keeling Plot" approach, which uses field-collected vapor samples coupled with a traditional isotope ratio mass spectrometer to infer the isotopic composition of evapotranspiration. However, fractionation accompanying inefficient vapor trapping can lead to large measurement uncertainty and the intensive laboring involved in cold-trap make it almost impossible for continuous measurements. Over the last 3-4 years a few groups have developed continuous approaches for measuring δ18O and δ2H that use laser absorption spectroscopy (LAS) to achieve accuracy levels similar to lab-based mass spectrometry methods. Unfortunately, most LAS systems need cryogenic cooling, constant calibration to a reference gas, and substantial power requirements, which make them unsuitable for long-term field deployment at remote field sites. In this research, we tested out a new LAS-based water vapor isotope analyzer (WVIA, Los Gatos Research, Inc, Mountain View, CA) based on Integrated Cavity Output Spectroscopy (ICOS) and coupled this instrument with a flux gradient system. The WVIA was calibrated bi-weekly using a dew point generator and water with known δ18O and δ2H signatures. The field work was performed at Morgan-Monroe State Forest Ameriflux tower site (central Indiana) between August 8 and August 27, 2008. The combination method was able to produce hourly δ18O and δ2H fluxes data with reproducibility similar to lab-based mass spectrometry methods. Such high temporal resolution data were also able to capture signatures of canopy and bare soil evaporation to individual rainfall events. The use of the ICOS water vapor analyzer within a gradient system has the

  6. Isotope geochemistry. Biological signatures in clumped isotopes of O₂.

    PubMed

    Yeung, Laurence Y; Ash, Jeanine L; Young, Edward D

    2015-04-24

    The abundances of molecules containing more than one rare isotope have been applied broadly to determine formation temperatures of natural materials. These applications of "clumped" isotopes rely on the assumption that isotope-exchange equilibrium is reached, or at least approached, during the formation of those materials. In a closed-system terrarium experiment, we demonstrate that biological oxygen (O2) cycling drives the clumped-isotope composition of O2 away from isotopic equilibrium. Our model of the system suggests that unique biological signatures are present in clumped isotopes of O2—and not formation temperatures. Photosynthetic O2 is depleted in (18)O(18)O and (17)O(18)O relative to a stochastic distribution of isotopes, unlike at equilibrium, where heavy-isotope pairs are enriched. Similar signatures may be widespread in nature, offering new tracers of biological and geochemical cycling.

  7. Determination of the isotopic composition of atmospheric methane and its application in the Antarctic

    NASA Technical Reports Server (NTRS)

    Lowe, David C.; Brenninkmeijer, Carl A. M.; Tyler, Stanley C.; Dlugkencky, Edward J.

    1991-01-01

    A procedure for establishing the C-13/C-12 ratio and the C-14 abundance in the atmospheric methane is discussed. The method involves air sample collection, measurement of the methane mixing ratio by gas chromotography followed by quantitative conversion of the methane in the air samples to CO2 and H2O, and analysis of the resulting CO2 for the C-13/C-12 ratio by stable isotope ratio mass spectrometry and measurement of C-14 content by accelerator mass spectrometry. The carbon isotropic composition of methane in air collected at Baring Head, New Zealand, and in air collected on aircraft flights between New Zealand and Antarctica is determined by the method, and no gradient in the composition between Baring Head and the South Pole station is found. As the technique is refined, and more data is gathered, small seasonal and long-term variations in C-13 are expected to be resolved.

  8. Methods for the separation of rhenium, osmium and molybdenum applicable to isotope geochemistry

    USGS Publications Warehouse

    Morgan, J.W.; Golightly, D.W.; Dorrzapf, A.F.

    1991-01-01

    Effective methods are described for the chemical separation of rhenium, osmium and molybdenum. The methods are based on distillation and anion-exchange chromatography, and have been the basis for rhenium-osmium isotope studies of ore deposits and meteorites. Successful anion-exchange separation of osmium requires both recognition and careful control of the osmium species in solution; thus, distillation of osmium tetroxide from a mixture of sulfuric acid and hydrogen peroxide is preferred to anion-exchange. Distribution coefficients measured for perrhenate in sulfuric acid media are sufficiently high (Kd > 500) for rhenium to be directly loaded onto an ion-exchange column from a distillation residue and subsequently eluted with nitric acid. Polymerization of molybdenum species during elution is prevented by use of a solution that is 1M in hydrochloric acid and 1M in sodium chloride. ?? 1991.

  9. A CYCLOTRON CONCEPT TO SUPPORT ISOTOPE PRODUCTION FOR SCIENCE AND MEDICAL APPLICATIONS

    SciTech Connect

    Egle, Brian; Mirzadeh, Saed; Tatum, B Alan; Varma, Venugopal Koikal; Bradley, Eric Craig; Burgess, Thomas W; Aaron, W Scott; Binder, Jeffrey L; Beene, James R; Saltmarsh, Michael John

    2013-01-01

    In August of 2009, the Nuclear Science Advisory Committee (NSAC) recommended a variable-energy, high-current multi-particle accelerator for the production of medical radioisotopes. The Oak Ridge National Laboratory is developing a technical concept for a 70 MeV dual-extraction multi-particle cyclotron that will meet the needs identified in the NSAC report. The cyclotron, which will be located at the Holifield Radioactive Ion Beam Facility (HRIBF), will operate on a 24/7 basis and will provide approximately 6000 hours per year of quality beam time for both the production R&D and production of medical and industrial radioisotopes. The proposed cyclotron will be capable of accelerating dual beams of 30 to 70 MeV H at up to 750 A, and up to 50 A of 15-35 MeV D , 35 MeV H2, and 70 MeV -particles. In dual-extraction H mode, a total of 750 A of 70 MeV protons will be provided simultaneously to both HRIBF and Isotope Production Facility. The isotope facility will consist of two target stations: a 2 water-cooled station and a 4 water-cooled high-energy-beam research station. The multi-particle capability and high beam power will enable research into new regimes of accelerator-produced radioisotopes, such as 225Ac, 211At, 68Ge, and 7B. The capabilities of the accelerator will enable the measurement of excitation functions, thick target yield measurements, research in high-power-target design, and will support fundamental research in nuclear and radiochemistry.

  10. Laser isotope separation

    DOEpatents

    Robinson, C.P.; Reed, J.J.; Cotter, T.P.; Boyer, K.; Greiner, N.R.

    1975-11-26

    A process and apparatus for separating isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light is described. A highly cooled gas of the volatile compound is produced in which the isotopic shift is sharpened and defined. Before substantial condensation occurs, the cooled gas is irradiated with laser light precisely tuned to a desired wavelength to selectively excite a particular isotopic species in the cooled gas. The laser light may impart sufficient energy to the excited species to cause it to undergo photolysis, photochemical reaction or even to photoionize. Alternatively, a two-photon irradiation may be applied to the cooled gas to induce photolysis, photochemical reaction or photoionization. The process is particularly applicable to the separation of isotopes of uranium.

  11. Photochemical isotope separation

    DOEpatents

    Robinson, C.P.; Jensen, R.J.; Cotter, T.P.; Greiner, N.R.; Boyer, K.

    1987-04-28

    A process is described for separating isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light. A highly cooled gas of the volatile compound is produced in which the isotopic shift is sharpened and defined. Before substantial condensation occurs, the cooled gas is irradiated with laser light precisely tuned to a desired wavelength to selectively excite a particular isotopic species in the cooled gas. The laser light may impart sufficient energy to the excited species to cause it to undergo photochemical reaction or even to photoionize. Alternatively, a two-photon irradiation may be applied to the cooled gas to induce photochemical reaction or photoionization. The process is particularly applicable to the separation of isotopes of uranium and plutonium. 8 figs.

  12. Laser isotope separation

    DOEpatents

    Robinson, C. Paul; Jensen, Reed J.; Cotter, Theodore P.; Boyer, Keith; Greiner, Norman R.

    1988-01-01

    A process and apparatus for separating isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light. A highly cooled gas of the volatile compound is produced in which the isotopic shift is sharpened and defined. Before substantial condensation occurs, the cooled gas is irradiated with laser light precisely tuned to a desired wavelength to selectively excite a particular isotopic species in the cooled gas. The laser light may impart sufficient energy to the excited species to cause it to undergo photolysis, photochemical reaction or even to photoionize. Alternatively, a two-photon irradiation may be applied to the cooled gas to induce photolysis, photochemical reaction or photoionization. The process is particularly applicable to the separation of isotopes of uranium.

  13. Photochemical isotope separation

    DOEpatents

    Robinson, C. Paul; Jensen, Reed J.; Cotter, Theodore P.; Greiner, Norman R.; Boyer, Keith

    1987-01-01

    A process for separating isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light. A highly cooled gas of the volatile compound is produced in which the isotopic shift is sharpened and defined. Before substantial condensation occurs, the cooled gas is irradiated with laser light precisely tuned to a desired wavelength to selectively excite a particular isotopic species in the cooled gas. The laser light may impart sufficient energy to the excited species to cause it to undergo photochemical reaction or even to photoionize. Alternatively, a two-photon irradiation may be applied to the cooled gas to induce photochemical reaction or photoionization. The process is particularly applicable to the separation of isotopes of uranium and plutonium.

  14. CALiPER Snapshot Report: Outdoor Area Lighting

    SciTech Connect

    None, None

    2016-09-30

    Snapshot reports use data from DOE's LED Lighting Facts product list to compare the LED performance to standard technologies, and are designed to help lighting retailers, distributors, designers, utilities, energy efficiency program sponsors, and other stakeholders understand the current state of the LED market and its trajectory.

  15. CALiPER Snapshot Report: MR16 Lamps - 2016

    SciTech Connect

    None, None

    2016-01-29

    Snapshot reports use data from DOE's LED Lighting Facts product list to compare the LED performance to standard technologies, and are designed to help lighting retailers, distributors, designers, utilities, energy efficiency program sponsors, and other stakeholders understand the current state of the LED market and its trajectory.

  16. CALiPER Snapshot Report: MR16 Lamps

    SciTech Connect

    2014-01-01

    Snapshot reports use data from DOE's LED Lighting Facts product list to compare the LED performance to standard technologies, and are designed to help lighting retailers, distributors, designers, utilities, energy efficiency program sponsors, and other stakeholders understand the current state of the LED market and its trajectory.

  17. CALiPER Snapshot Report: Indoor LED Luminaires

    SciTech Connect

    2014-04-01

    Snapshot reports use data from DOE's LED Lighting Facts product list to compare the LED performance to standard technologies, and are designed to help lighting retailers, distributors, designers, utilities, energy efficiency program sponsors, and other stakeholders understand the current state of the LED market and its trajectory.

  18. CALiPER Snapshot Report: Outdoor Area Lighting

    SciTech Connect

    none,

    2014-07-01

    Snapshot reports use data from DOE's LED Lighting Facts product list to compare the LED performance to standard technologies, and are designed to help lighting retailers, distributors, designers, utilities, energy efficiency program sponsors, and other stakeholders understand the current state of the LED market and its trajectory.

  19. Energy Transition Initiative, Island Energy Snapshot - Turks & Caicos (Fact Sheet)

    SciTech Connect

    Not Available

    2015-02-01

    This profile presents a snapshot of the electricity generation and reduction technologies, including solar hot water heating, available to Turks and Caicos - a British overseas territory consisting of two groups of islands located southeast of the Bahamas. Heating and transportation fuels are not addressed.

  20. Energy Transition Initiative, Island Energy Snapshot - Bahamas (Fact Sheet)

    SciTech Connect

    Not Available

    2015-02-01

    This profile provides a snapshot of the electricity generation or reduction technologies, including solar hot water heating, available to the Commonwealth of the Bahamas - a country consisting of more than 700 islands, cays, and islets - of which only 30 are actually inhabited. Heating and transportation fuels are not addressed.

  1. Energy Transition Initiative: Island Energy Snapshot - St. Lucia (Fact Sheet)

    SciTech Connect

    Not Available

    2015-02-01

    This profile provides a snapshot of the electricity generation or reduction technologies, including solar hot water heating, available to Saint Lucia, one of six Caribbean countries that make up the Windward Islands - the southern arc of the Lesser Antilles chain - at the eastern end of the Caribbean Sea. Heating and transportation fuels are not addressed.

  2. Fractal snapshot components in chaos induced by strong noise.

    PubMed

    Bódai, Tamás; Károlyi, György; Tél, Tamás

    2011-04-01

    In systems exhibiting transient chaos in coexistence with periodic attractors, the inclusion of weak noise might give rise to noise-induced chaotic attractors. When the noise amplitude exceeds a critical value, an extended attractor appears along the fractal unstable manifold of the underlying nonattracting chaotic set. A further increase of noise leads to a fuzzy nonfractal pattern. By means of the concept of snapshot attractors and random maps, we point out that the fuzzy pattern can be decomposed into well-defined fractal components, the snapshot attractors belonging to a given realization of the noise and generated by following an ensemble of noisy trajectories. The pattern of the snapshot attractor and its characteristic numbers, such as the finite time Lyapunov exponents and numerically evaluated fractal dimensions, change continuously in time. We find that this temporal fluctuation is a robust property of the system which hardly changes with increasing ensemble size. The validity of the Kaplan-Yorke formula is also investigated. A superposition of about 100 snapshot attractors provides a good approximant to the fuzzy noise-induced attractor at the same noise strength.

  3. A Snapshot of Organizational Climate: Perceptions of Extension Faculty

    ERIC Educational Resources Information Center

    Tower, Leslie E.; Bowen, Elaine; Alkadry, Mohamad G.

    2011-01-01

    This article provides a snapshot of the perceptions of workplace climate of Extension faculty at a land-grant, research-high activity university, compared with the perceptions of non-Extension faculty at the same university. An online survey was conducted with a validated instrument. The response rate for university faculty was 44% (968); the…

  4. Drama and Theatre Education in Canada: A Snapshot

    ERIC Educational Resources Information Center

    Carter, Mindy R.

    2014-01-01

    This "Note from the Field" provides an overview of what is happening in Kindergarten to University drama and theatre education across Canada. In addition to this snapshot I offer some considerations for extending this discipline and its potential impact on curriculum, policy and practice.

  5. 48. Photocopy of photograph (from polaroid snapshot in Burlington Northern ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    48. Photocopy of photograph (from polaroid snapshot in Burlington Northern Railroad correspondence files, October, 1957) SHEAR FENCE DAMAGE FROM M/V/ KORSHOLMA COLLISION - Burlington Northern Railroad Bridge, Spanning Willamette River at River Mile 6.9, Portland, Multnomah County, OR

  6. A Snapshot of Organizational Climate: Perceptions of Extension Faculty

    ERIC Educational Resources Information Center

    Tower, Leslie E.; Bowen, Elaine; Alkadry, Mohamad G.

    2011-01-01

    This article provides a snapshot of the perceptions of workplace climate of Extension faculty at a land-grant, research-high activity university, compared with the perceptions of non-Extension faculty at the same university. An online survey was conducted with a validated instrument. The response rate for university faculty was 44% (968); the…

  7. Minority Student Report 2005: A Snapshot of Arizona's Educational Achievement

    ERIC Educational Resources Information Center

    Forester, Christine A.; Drake, Tonya M.

    2005-01-01

    This document, from the Arizona Minority Education Policy Analysis Center (AMEPAC), reports the educational achievement of minority students in Arizona, from kindergarten through college. As a snapshot it is simply a description of what is, and the data are, thus, open to interpretation. How the numbers look and what they mean may be two different…

  8. A Snapshot of Children on the California Border

    ERIC Educational Resources Information Center

    Children Now, 2004

    2004-01-01

    This snapshot of children on the California border examines the well-being of children along the U.S.-Mexico border, comparing California, Texas, New Mexico and Arizona. It indicates more than one-quarter of all California residents are foreign born (26%), compared to 8% of residents in non-border states. In Texas, the percentage of the population…

  9. CALiPER Snapshot Report: Linear Lamps (TLEDs)

    SciTech Connect

    None, None

    2016-07-01

    Snapshot reports use data from DOE's LED Lighting Facts product list to compare the LED performance to standard technologies, and are designed to help lighting retailers, distributors, designers, utilities, energy efficiency program sponsors, and other stakeholders understand the current state of the LED market and its trajectory.

  10. Implementation of Response to Intervention: A Snapshot of Progress

    ERIC Educational Resources Information Center

    Berkeley, Sheri; Bender, William N.; Peaster, Lindsay Gregg; Saunders, Lauren

    2009-01-01

    This article provides a snapshot of how all 50 states are progressing with the development and implementation of response-to-intervention (RtI) models 1 year after the final regulations for the Individuals with Disabilities Education Act were passed. Data were collected through a review of existing state department of education Web sites and…

  11. Drama and Theatre Education in Canada: A Snapshot

    ERIC Educational Resources Information Center

    Carter, Mindy R.

    2014-01-01

    This "Note from the Field" provides an overview of what is happening in Kindergarten to University drama and theatre education across Canada. In addition to this snapshot I offer some considerations for extending this discipline and its potential impact on curriculum, policy and practice.

  12. Snapshots of mathematics teacher noticing during task design

    NASA Astrophysics Data System (ADS)

    Choy, Ban Heng

    2016-09-01

    Designing a mathematically worthwhile task is critical for promoting students' reasoning. To improve task design skills, teachers often engage in collaborative lesson planning activities such as lesson study. However, to learn from the process of lesson study, it is important for teachers to notice productively the concepts, students' confusion and the design of the task. But what researchers mean by productive noticing varies. In this article, I present the FOCUS Framework which highlights two characteristics of productive noticing: having an explicit focus for noticing and focusing noticing through pedagogical reasoning. Using these two characteristics, I develop snapshots of noticing as a representation of practice to present a fine-grained analysis of teacher noticing. Through vignettes of teachers discussing the design of a task to teach fractions, I illustrate how two teachers' noticing can be analysed and represented using snapshots of noticing. To conclude, I highlight what snapshots of noticing tell us about a teacher's noticing and suggest ways to use these snapshots in future studies of noticing.

  13. Applications of UThPb isotope systematics to the problems of radioactive waste disposal

    USGS Publications Warehouse

    Stuckless, J.S.

    1986-01-01

    Concentrations of U, Th and Pb, and the isotopic composition of Pb for whole-rock samples of granitoids show: (1) that open-system behavior is nearly universal in the surface and near-surface environment; and (2) that elemental mobility is possible to depths of several hundred meters. Several identified or at least postulated factors that control U and/or Pb mobility include: (1) the mineralogical sites for U and its daughter products; (2) access of groundwater to these sites; (3) the volume of circulating water; and (4) the chemistry of the groundwater. Studies of granitic samples from peralkaline complexes in the Arabian Shield have shown that most samples lost less than 20% of their U during recent exposure to the near-surface environment. Most of the U in these samples appears to be firmly bound in zircons. In contrast, most surface and shallow drill-core samples of the granite of Lankin Dome (Granite Mountains, Wyoming) have lost ??? 70% of their U. Most of the U in these samples is weakly bound in biotite and epidote-family minerals. The granite recovered during the Illinois Deep Drill Hole Project (Stephenson County, Illinois) is mineralogically similar to the granite of Lankin Dome, but this granite lost radiogenic Pb rather than U, probably as a result of exposure to groundwater that had a markedly different chemistry from that in the Granite Mountains. Studies of the Sherman Granite (Wyoming) and the Go??temar Granite (southeastern Sweden) have shown that U and/or Pb mobility is greatest in and near fractured rock. The greater mobility is interpreted to be the result of both a larger water/rock ratio in the fractured rock and exposure to water over an increased surface area (and consequently a greater number of uranium sites). Several types of geochemical and mineralogic data can be used to identify rock-water interaction in granites; however, if rock samples have favorable radiogenic to common Pb ratios, both the amount and approximate timing of U or Pb

  14. Tracing diatom utilisation, and its fate, in Lake Baikal, Siberia: the application of silicon isotope geochemistry

    NASA Astrophysics Data System (ADS)

    Panizzo, V. N.; Swann, G. E. A.; Mackay, A. W.; Roberts, S.; Vologina, E.; Sturm, M.; Horstwood, M. S.

    2014-12-01

    The global biogeochemical cycling of silicon (Si) is intrinsically linked to the fate of CO2 in the earth's atmosphere. To date, most research has focused on the oceanic cycling of Si over glacial/interglacial timescales although, the importance of continental Si cycling (via abiotic and biotic processes) is now being addressed. Especially as the significant potential for Si sequestration in continental lake systems has been recently highlighted [1]. We present the first large-scale silicon isotope (δ30SiDSi) profiles of Lake Baikal's water column, where a comparison between both pre- and post-diatom growing season δ30SiDSi signatures are made. Samples were collected along a water profile (surface to 180 m) at numerous sites across Lake Baikal, with deep-water endmembers at 400 m and c. 1,500 m. All isotopic analyses were conducted on a Neptune + Multi-Collector ICP-MS at NIGL, UK, using wet plasma mode with Mg doping of samples and standard-sample-standard bracketing. Analytical reproducibility is 0.12‰ (2σ) and blanks are <1% of signal intensity. DSi concentrations of March water surface samples (South Basin only) range between c. 0.74 and 1.23 ppm while those collected in August are all <0.70 ppm, following seasonal biological utilisation. In turn Chlorophyll a values from South Basin profiles in August are greater (between c. 1.46 to 3.18 mg l-1) than March surface values (<0.70 mg l-1). Indeed, March δ30SiDSi surface values range between c. +2.16 and +2.45‰ while summer surface values range between c. +2.20 and +2.84‰, reflecting residual pool depletion after summer biological utilisation. δ30SiDSi values are >1‰ more enriched than dominant lake water inflows again reflecting diatom Si uptake. Annual open sediment traps deployed down Lake Baikal's water column yield δ30Sidiatom signatures of +1.25‰, which suggests that down-column diatom dissolution is minimal. Applying the diatom fractionation factor of -1.1‰[2] and adopting a closed system

  15. Triple Oxygen Isotopic Variation in Continental Waters and Potential Applications to Paleoclimate Research

    NASA Astrophysics Data System (ADS)

    Levin, N. E.; Li, S.

    2014-12-01

    18O/16O ratios are widely used in paleoclimate studies as proxies for temperature, precipitation amount and hydrologic change, but interpretations of these records are often challenged by the multiple factors that can influence them. Variation in 17O/16O ratios of Earth materials have long been assumed to covary with 18O/16O ratios in predictable and uniform ways such that they were not considered useful in studies of Phanerozoic climate. However, recent advances in the ability to measure small differences in 17O-excess, the deviation from an expected relationship between 18O/16O and 17O/16O ratios, in both waters and low-temperature minerals and rocks (e.g., carbonates, bioapatites, silicates, oxides) present the opportunity to use triple oxygen isotope measurements in hydrological and paleoclimate studies. In particular, the sensitivity of 17O-excess to kinetic fractionation means that it can be used to constrain the influence of kinetic effects on variations in δ18O. Here we review recently generated datasets on the triple oxygen isotope composition of the hydrosphere and show that there is considerably more variation in 17O-excess of continental waters than initially proposed. A compilation of 17O-excess data from precipitation, which includes snow from polar regions, tropical storms and weekly precipitation collections from mid-latitudes, shows that the 17O-excess of precipitation can range from -0.06 to +0.07‰. A continent-wide survey of tap waters from the U.S. mirrors the variation observed in precipitation. Among leaf waters, 17O-excess values range from -0.28 to +0.04‰ and can vary by as much as 0.16‰ in a plant within a single day. The mass-dependent effects associated with kinetic fractionation are likely responsible for the majority of the observed variation in waters, either during re-evaporation of rainfall at warmer temperatures, snow formation at very cold temperatures, or evapotranspiration within leaf waters. In summary, the combination of

  16. Relationships between water and paddlefish Polyodon spathula dentary elemental and stable-isotopic signatures: potential application for reconstructing environmental history.

    PubMed

    Bock, L R; Whitledge, G W; Pracheil, B; Bailey, P

    2017-02-01

    The objectives of this study were to characterize relationships between water and paddlefish Polyodon spathula dentary Sr:Ca, δ(18) O and stable hydrogen isotope ratio (δD) to determine the accuracy with which individual P. spathula could be assigned to their collection locations using dentary-edge Sr:Ca, δD and δ(18) O. A laboratory experiment was also conducted to determine whether dentary Sr:Ca in age 0 year P. spathula would reflect shifts in water Sr:Ca to which fish were exposed. Significant linear relationships between water and dentary Sr:Ca, δD and δ(18) O were observed, although the relationship between water and dentary δ(18) O was weaker than those for Sr:Ca and δD. Classification success for individual fish to collection locations that differed in water Sr:Ca, δD and δ(18) O ranged from 86 to 100% based on dentary-edge Sr:Ca, δD and δ(18) O. Dentary Sr:Ca increased significantly in laboratory-reared age 0 year P. spathula following 4 weeks of exposure to elevated water Sr:Ca; dentary Sr:Ca of fish held in water with elevated Sr:Ca was also significantly higher than that of control fish reared in ambient laboratory water. Results indicated that P. spathula dentaries reflect water signatures for commonly-applied natural chemical markers and strongly suggest that dentary microchemistry and stable-isotopic compositions will be applicable for reconstructing P. spathula environmental history in locations where sufficient spatial differences in water chemistry occur.

  17. Bomb-curve radiocarbon measurement of recent biologic tissues and applications to wildlife forensics and stable isotope (paleo)ecology

    PubMed Central

    Uno, Kevin T.; Quade, Jay; Fisher, Daniel C.; Wittemyer, George; Douglas-Hamilton, Iain; Andanje, Samuel; Omondi, Patrick; Litoroh, Moses; Cerling, Thure E.

    2013-01-01

    Above-ground thermonuclear weapons testing from 1952 through 1962 nearly doubled the concentration of radiocarbon (14C) in the atmosphere. As a result, organic material formed during or after this period may be radiocarbon-dated using the abrupt rise and steady fall of the atmospheric 14C concentration known as the bomb-curve. We test the accuracy of accelerator mass spectrometry radiocarbon dating of 29 herbivore and plant tissues collected on known dates between 1905 and 2008 in East Africa. Herbivore samples include teeth, tusks, soft tissue, hair, and horn. Tissues formed after 1955 are dated to within 0.3–1.3 y of formation, depending on the tissue type, whereas tissues older than ca. 1955 have high age uncertainties (>17 y) due to the Suess effect. 14C dating of tissues has applications to stable isotope (paleo)ecology and wildlife forensics. We use data from 41 additional samples to determine growth rates of tusks, molars, and hair, which improve interpretations of serial stable isotope data for (paleo)ecological studies. 14C dating can also be used to calculate the time interval represented in periodic histological structures in dental tissues (i.e., perikymata), which in turn may be used as chronometers in fossil teeth. Bomb-curve 14C dating of confiscated animal tissues (e.g., ivory statues) can be used to determine whether trade of the item is legal, because many Convention of International Trade of Endangered Species restrictions are based on the age of the tissue, and thus can serve as a powerful forensic tool to combat illegal trade in animal parts. PMID:23818577

  18. Bomb-curve radiocarbon measurement of recent biologic tissues and applications to wildlife forensics and stable isotope (paleo)ecology.

    PubMed

    Uno, Kevin T; Quade, Jay; Fisher, Daniel C; Wittemyer, George; Douglas-Hamilton, Iain; Andanje, Samuel; Omondi, Patrick; Litoroh, Moses; Cerling, Thure E

    2013-07-16

    Above-ground thermonuclear weapons testing from 1952 through 1962 nearly doubled the concentration of radiocarbon ((14)C) in the atmosphere. As a result, organic material formed during or after this period may be radiocarbon-dated using the abrupt rise and steady fall of the atmospheric (14)C concentration known as the bomb-curve. We test the accuracy of accelerator mass spectrometry radiocarbon dating of 29 herbivore and plant tissues collected on known dates between 1905 and 2008 in East Africa. Herbivore samples include teeth, tusks, soft tissue, hair, and horn. Tissues formed after 1955 are dated to within 0.3-1.3 y of formation, depending on the tissue type, whereas tissues older than ca. 1955 have high age uncertainties (>17 y) due to the Suess effect. (14)C dating of tissues has applications to stable isotope (paleo)ecology and wildlife forensics. We use data from 41 additional samples to determine growth rates of tusks, molars, and hair, which improve interpretations of serial stable isotope data for (paleo)ecological studies. (14)C dating can also be used to calculate the time interval represented in periodic histological structures in dental tissues (i.e., perikymata), which in turn may be used as chronometers in fossil teeth. Bomb-curve (14)C dating of confiscated animal tissues (e.g., ivory statues) can be used to determine whether trade of the item is legal, because many Convention of International Trade of Endangered Species restrictions are based on the age of the tissue, and thus can serve as a powerful forensic tool to combat illegal trade in animal parts.

  19. Bomb-curve radiocarbon measurement of recent biologic tissues and applications to wildlife forensics and stable isotope (paleo)ecology

    NASA Astrophysics Data System (ADS)

    Uno, Kevin T.; Quade, Jay; Fisher, Daniel C.; Wittemyer, George; Douglas-Hamilton, Iain; Andanje, Samuel; Omondi, Patrick; Litoroh, Moses; Cerling, Thure E.

    2013-07-01

    Above-ground thermonuclear weapons testing from 1952 through 1962 nearly doubled the concentration of radiocarbon (14C) in the atmosphere. As a result, organic material formed during or after this period may be radiocarbon-dated using the abrupt rise and steady fall of the atmospheric 14C concentration known as the bomb-curve. We test the accuracy of accelerator mass spectrometry radiocarbon dating of 29 herbivore and plant tissues collected on known dates between 1905 and 2008 in East Africa. Herbivore samples include teeth, tusks, soft tissue, hair, and horn. Tissues formed after 1955 are dated to within 0.3-1.3 y of formation, depending on the tissue type, whereas tissues older than ca. 1955 have high age uncertainties (>17 y) due to the Suess effect. 14C dating of tissues has applications to stable isotope (paleo)ecology and wildlife forensics. We use data from 41 additional samples to determine growth rates of tusks, molars, and hair, which improve interpretations of serial stable isotope data for (paleo)ecological studies. 14C dating can also be used to calculate the time interval represented in periodic histological structures in dental tissues (i.e., perikymata), which in turn may be used as chronometers in fossil teeth. Bomb-curve 14C dating of confiscated animal tissues (e.g., ivory statues) can be used to determine whether trade of the item is legal, because many Convention of International Trade of Endangered Species restrictions are based on the age of the tissue, and thus can serve as a powerful forensic tool to combat illegal trade in animal parts.

  20. Sensitive, Efficient Quantitation of 13C-Enriched Nucleic Acids via Ultrahigh-Performance Liquid Chromatography–Tandem Mass Spectrometry for Applications in Stable Isotope Probing

    PubMed Central

    Wilhelm, Roland; Szeitz, András; Klassen, Tara L.

    2014-01-01

    Stable isotope probing (SIP) of nucleic acids is a powerful tool for studying the functional traits of microbial populations within complex communities, but SIP involves a number of technical challenges. Many of the difficulties in DNA-SIP and RNA-SIP experiments can be effectively overcome with an efficient, sensitive method for quantitating the isotopic enrichment of nucleic acids. Here, we present a sensitive method for quantitating 13C enrichment of nucleic acids, requiring a few nanograms of sample, and we demonstrate its utility in typical DNA-SIP and RNA-SIP experiments. All five nucleobases (adenine, guanine, cytosine, thymine, and uracil) were separated and detected by using ultrahigh-performance liquid chromatography–tandem mass spectrometry. We detected all isotopic species in samples with as low as 1.5 atom% 13C above natural abundance, using 1-ng loadings. Quantitation was used to characterize the isotopic enrichment kinetics of cellulose- and lignin-based microcosm experiments and to optimize the recovery of enriched nucleic acids. Application of our method will minimize the quantity of expensive isotopically labeled substrates required and reduce the risk of failed experiments due to insufficient recovery of labeled nucleic acids for sequencing library preparation. PMID:25217022

  1. Sensitive, Efficient Quantitation of 13C-Enriched Nucleic Acids via Ultrahigh-Performance Liquid Chromatography-Tandem Mass Spectrometry for Applications in Stable Isotope Probing.

    PubMed

    Wilhelm, Roland; Szeitz, András; Klassen, Tara L; Mohn, William W

    2014-12-01

    Stable isotope probing (SIP) of nucleic acids is a powerful tool for studying the functional traits of microbial populations within complex communities, but SIP involves a number of technical challenges. Many of the difficulties in DNA-SIP and RNA-SIP experiments can be effectively overcome with an efficient, sensitive method for quantitating the isotopic enrichment of nucleic acids. Here, we present a sensitive method for quantitating (13)C enrichment of nucleic acids, requiring a few nanograms of sample, and we demonstrate its utility in typical DNA-SIP and RNA-SIP experiments. All five nucleobases (adenine, guanine, cytosine, thymine, and uracil) were separated and detected by using ultrahigh-performance liquid chromatography-tandem mass spectrometry. We detected all isotopic species in samples with as low as 1.5 atom% (13)C above natural abundance, using 1-ng loadings. Quantitation was used to characterize the isotopic enrichment kinetics of cellulose- and lignin-based microcosm experiments and to optimize the recovery of enriched nucleic acids. Application of our method will minimize the quantity of expensive isotopically labeled substrates required and reduce the risk of failed experiments due to insufficient recovery of labeled nucleic acids for sequencing library preparation.

  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.

    PubMed

    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)ZnJMC = +0.49 ± 0.06‰, 2σ, n = 3) compared to sampling locations outside (δ(66)ZnJMC = +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. Application of Three-Class ROC Analysis to Task-Based Image Quality Assessment of Simultaneous Dual-Isotope Myocardial Perfusion SPECT (MPS)

    PubMed Central

    He, Xin; Song, Xiyun; Frey, Eric C.

    2009-01-01

    The diagnosis of cardiac disease using dual-isotope myocardial perfusion SPECT (MPS) is based on the defect status in both stress and rest images, and can be modeled as a three-class task of classifying patients as having no, reversible, or fixed perfusion defects. Simultaneous acquisition protocols for dual-isotope MPS imaging have gained much interest due to their advantages including perfect registration of the 201Tl and 99mTc images in space and time, increased patient comfort, and higher clinical throughput. As a result of simultaneous acquisition, however, crosstalk contamination, where photons emitted by one isotope contribute to the image of the other isotope, degrades image quality. Minimizing the crosstalk is important in obtaining the best possible image quality. One way to minimize the crosstalk is to optimize the injected activity of the two isotopes by considering the three-class nature of the diagnostic problem. To effectively do so, we have previously developed a three-class receiver operating characteristic (ROC) analysis methodology that extends and unifies the decision theoretic, linear discriminant analysis, and psychophysical foundations of binary ROC analysis in a three-class paradigm. In this work, we applied the proposed three-class ROC methodology to the assessment of the image quality of simultaneous dual-isotope MPS imaging techniques and the determination of the optimal injected activity combination. In addition to this application, the rapid development of diagnostic imaging techniques has produced an increasing number of clinical diagnostic tasks that involve not only disease detection, but also disease characterization and are thus multiclass tasks. This paper provides a practical example of the application of the proposed three-class ROC analysis methodology to medical problems. PMID:18955172

  4. Application of Carbon Isotope Fractionation during the Reduction Process from CO 2 to CH 4

    NASA Astrophysics Data System (ADS)

    Li, Jin; Hu, Guoyi; Zhang, Ying; Yang, Guifang; Cui, Huiying; Cao, Hongming; Hu, Xülong

    The CO 2 reduced to CH 4 pathway is important for the generation of biogas in the geological history. The Quaternary biogenic gas fields in Qaidam Basin of China belong to the CO 2/H 2 reduction biogenic gas. According to the theory of H 2/CO 2 reduction, we have carried out the biosimulation experiments with different occurrences and different initial carbon isotope values of carbon sources. The experimental results indicate that there is a positive correlation between the δ 13C methane values and the δ 13C values of the substrate in products; In response to the existence of excessive substrate, the occurrence of substrate has its effect on the δ 13C methane values. The δ 13C methane values from free CO 2 reduced to CH 4 is relatively lower than those coming from HCO 3- and CO 32- ions. By applying to the Quaternary biogenic gas filed in the east of Qaidam Basin, the source and occurrences of the main substrate CO 2 are discussed, and these have import reference significance for evaluating the biogas resources and searching for favorable exploration areas.

  5. Application of isotope dilution mass spectrometry: determination of ochratoxin A in the Canadian Total Diet Study

    PubMed Central

    Tam, J.; Pantazopoulos, P.; Scott, P.M.; Moisey, J.; Dabeka, R.W.; Richard, I.D.K.

    2011-01-01

    Analytical methods are generally developed and optimized for specific commodities. Total Diet Studies, representing typical food products ‘as consumed’, pose an analytical challenge since every food product is different. In order to address this technical challenge, a selective and sensitive analytical method was developed suitable for the quantitation of ochratoxin A (OTA) in Canadian Total Diet Study composites. The method uses an acidified solvent extraction, an immunoaffinity column (IAC) for clean-up, liquid chromatography-tandem mass spectrometry (LC-MS/MS) for identification and quantification, and a uniformly stable isotope-labelled OTA (U-[13C20]-OTA) as an internal recovery standard. Results are corrected for this standard. The method is accurate (101% average recovery) and precise (5.5% relative standard deviation (RSD)) based on 17 duplicate analysis of various food products over 2 years. A total of 140 diet composites were analysed for OTA as part of the Canadian Total Diet Study. Samples were collected at retail level from two Canadian cities, Quebec City and Calgary, in 2008 and 2009, respectively. The results indicate that 73% (102/140) of the samples had detectable levels of OTA, with some of the highest levels of OTA contamination found in the Canadian bread supply. PMID:21623499

  6. Applications and Advantages of Stable Isotope Phosphate Labeling of RNA in Mass Spectrometry.

    PubMed

    Borland, Kayla; Limbach, Patrick A

    2017-04-01

    Mass spectrometry (MS) has become an enabling technology for the characterization of post-transcriptionally modified nucleosides within ribonucleic acids (RNAs). These modified RNAs tend to be more challenging to completely characterize using conventional genomic-based sequencing technologies. As with many biological molecules, information relating to the presence or absence of a particular compound (i.e., qualitative measurement) is only one step in sample characterization. Additional useful information is found by performing quantitative measurements on the levels of the compound of interest in the sample. Phosphate labeling of modified RNAs has been developed by our laboratory to enhance conventional mass spectrometry techniques. By taking advantage of the mechanism of action of many ribonucleases (RNases), digesting RNA samples in the presence of (18)O-labeled water generates an (18)O-labeled 3'-phosphate in each digestion product. We describe the historical development of this approach, contrast this stable isotope labeling strategy with others used in RNA mass spectrometry, and provide examples of new analytical mass spectrometry methods that are enabled by phosphate labeling in this fashion.

  7. Neutron capture cross-section studies of Tellurium isotopes for neutrinoless double beta decay applications

    NASA Astrophysics Data System (ADS)

    Bhike, Megha; Tornow, Werner

    2014-09-01

    The CUORE detector at Gran Sasso, aimed at searching for neutrinoless double-beta decay of 130Te, employs an array of TeO2 bolometer modules. To understand and identify the contribution of muon and (α,n) induced neutrons to the CUORE background, fast neutron cature cross-section data of the tellurium isotopes 126Te, 128Te and 130Te have been measured with the activation method at eight different energies in the neutron energy range 0.5-7.5 MeV. Plastic pill boxes of diameter 1.6 cm and width 1 cm containing Te were irradiated with mono-energetic neutrons produced via the 3H(p,n)3He and 2H(d,n)3He reactions. The cross-sections were determined relative to the 197Au(n, γ)198Au and 115In(n,n')115m In standard cross sections. The activities of the products were measured using 60% lead-shielded HPGe detectors at TUNL's low background counting facility. The present results are compared with the evaluated data from TENDL-2012, ENDF/B-VII.1, JEFF-3.2 and JENDL-4.0, as well as with literature data.

  8. Application of (13)C-stable isotope probing to identify RDX-degrading microorganisms in groundwater.

    PubMed

    Cho, Kun-Ching; Lee, Do Gyun; Roh, Hyungkeun; Fuller, Mark E; Hatzinger, Paul B; Chu, Kung-Hui

    2013-07-01

    We employed stable isotope probing (SIP) with (13)C-labeled hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to identify active microorganisms responsible for RDX biodegradation in groundwater microcosms. Sixteen different 16S rRNA gene sequences were derived from microcosms receiving (13)C-labeled RDX, suggesting the presence of microorganisms able to incorporate carbon from RDX or its breakdown products. The clones, residing in Bacteroidia, Clostridia, α-, β- and δ-Proteobacteria, and Spirochaetes, were different from previously described RDX degraders. A parallel set of microcosms was amended with cheese whey and RDX to evaluate the influence of this co-substrate on the RDX-degrading microbial community. Cheese whey stimulated RDX biotransformation, altered the types of RDX-degrading bacteria, and decreased microbial community diversity. Results of this study suggest that RDX-degrading microorganisms in groundwater are more phylogenetically diverse than what has been inferred from studies with RDX-degrading isolates. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Applications of the two-photon doppler-free method: Hyperfine interactions and isotope shift measurements

    NASA Astrophysics Data System (ADS)

    Cagnac, B.

    1985-08-01

    The hyperfine structures are generally of the same order of magnitude as the Doppler broadening of optical transitions and so are the isotopic shifts in the case of heavy elements. When these structures are too small, one must use Doppler-free methods. Among these methods, the two-photon spectroscopy has obtained good results in highly excited levels. In our laboratory in Paris, we did measurements on neon and helium by two-photon excitation from metastable levels. The precision of the measurements is of the order of one MHz, which permits a precise comparison with theory. We compare the measurements on neon with the theory by Liberman and we obtain a good fit in the first approximation, but must introduce mixing of wave functions for an exact explanation. In the case of helium, we obtain a good fit with the theoretical values obtained from the wave functions by Accad, Pekeris and Schiff. We also give an example where another technique by polarization measurements permits us to obtain experimentally a hyperfine structure smaller than the natural width. We also present a short review of the measurements done by the two-photon method in other laboratories on other elements, Pb, Tl, In and alkaline earths Ca, Sr. Ba.

  10. Selective isotopic enrichment of synthetic RNA: application to the HIV-1 TAR element.

    PubMed

    Michnicka, M J; Harper, J W; King, G C

    1993-01-19

    The introduction of isotopically enriched nucleotides into NMR quantities of a synthetic 29-mer RNA derived from the HIV-1 TAR element is described. RNA enriched in 13C and/or 15N is produced by a procedure which involves isolation of whole cellular RNA from Escherichia coli, nucleolysis, separation of mononucleotides, chemical or enzymatic pyrophosphorylation, and in vitro transcription by T7 RNA polymerase. Spectral characteristics of each residue type are examined in isolation. 13C chemical shifts provide an alternative method to determine ribose puckers for larger RNAs. Nonprotonated sites such as purine N7 groups can now be monitored through the use of multiple-bond 1H-15N coupling. When applied conservatively, coordinate analysis of chemical shift values should prove valuable for NMR studies of RNA structure and recognition. 1H, 13C, and 15N chemical shift data suggest that TAR residue A35 has an unusual local environment, consistent with extrusion of its base from the terminal loop.

  11. The Application of Methane Clumped Isotope Measurements to Determine the Source of Large Methane Seeps in Alaskan Lakes

    NASA Astrophysics Data System (ADS)

    Douglas, P. M.; Stolper, D. A.; Eiler, J. M.; Sessions, A. L.; Walter Anthony, K. M.

    2014-12-01

    Natural methane emissions from the Arctic present an important potential feedback to global warming. Arctic methane emissions may come from either active microbial sources or from deep fossil reservoirs released by the thawing of permafrost and melting of glaciers. It is often difficult to distinguish between and quantify contributions from these methane sources based on stable isotope data. Analyses of methane clumped isotopes (isotopologues with two or more rare isotopes such as 13CH3D) can complement traditional stable isotope-based classifications of methane sources. This is because clumped isotope abundances (for isotopically equilibrated systems) are a function of temperature and can be used to identify pathways of methane generation. Additionally, distinctive effects of mixing on clumped isotope abundances make this analysis valuable for determining the origins of mixed gasses. We find large variability in clumped isotope compositions of methane from seeps in several lakes, including thermokarst lakes, across Alaska. At Lake Sukok in northern Alaska we observe the emission of dominantly thermogenic methane, with a formation temperature of at least 100° C. At several other lakes we find evidence for mixing between thermogenic methane and biogenic methane that forms in low-temperature isotopic equilibrium. For example, at Eyak Lake in southeastern Alaska, analysis of three methane samples results in a distinctive isotopic mixing line between a high-temperature end-member that formed between 100-170° C, and a biogenic end-member that formed in isotopic equilibrium between 0-20° C. In this respect, biogenic methane in these lakes resembles observations from marine gas seeps, oil degradation, and sub-surface aquifers. Interestingly, at Goldstream Lake in interior Alaska, methane with strongly depleted clumped-isotope abundances, indicative of disequilibrium gas formation, is found, similar to observations from methanogen culture experiments.

  12. Application of high-precision isotope ratio monitoring mass spectrometry to identify the biosynthetic origins of proteins

    PubMed Central

    Apostol, Izydor; Brooks, Paul D.; Mathews, Antony J.

    2001-01-01

    Isotope ratio monitoring (IRM) mass spectrometry was used to measure the relative abundance of stable isotopes in several samples of adult human hemoglobin expressed in E. coli, yeast, and human blood. The results showed significant differences in the distribution of 15N and 13C isotopes among hemoglobin samples produced in these organisms. This indicates that IRM mass spectrometry can be used in forensic protein chemistry to identify the origin of protein expression. PMID:11420448

  13. Application of GelGreen™ in Cesium Chloride Density Gradients for DNA-Stable Isotope Probing Experiments

    PubMed Central

    Pan, Kailing; Li, Hongyu; Fan, Xiaoyan; Sun, Lixin; Zhang, Shujun; Gao, Yongqing

    2017-01-01

    In this study, GelGreen™ was investigated as a replacement for SYBR® Safe to stain DNA in cesium chloride (CsCl) density gradients for DNA-stable isotope probing (SIP) experiments. Using environmental DNA, the usage of GelGreen™ was optimized for sensitivity compared to SYBR® Safe, its optimal concentration, detection limit for environmental DNA and its application in environmental DNA-SIP assay. Results showed that GelGreen™ was more sensitive than SYBR® Safe, while the optimal dosage (15X concentration) needed was approximately one-third of SYBR® Safe, suggesting that its sensitivity was three times more superior than SYBR® Safe. At these optimal parameters, the detection limit of GelGreen™-stained environmental DNA was as low as 0.2 μg, but the usage of 0.5 μg environmental DNA was recommended to produce a more consistent DNA band. In addition, a modified needle extraction procedure was developed to withdraw DNA effectively by fractionating CsCl density gradients into four or five fractions. The successful application of GelGreen™ staining with 13C-labeled DNA from enriched activated sludge suggests that this stain was an excellent alternative of SYBR® Safe in CsCl density gradients for DNA-SIP assays. PMID:28056074

  14. APPLICATION OF THE NATURALLY-OCCURRING DEUTERIUM ISOTOPE TO TRACING THE CAPILLARY FRINGE

    EPA Science Inventory

    Naturally-occurring deuterium is a useful tracer of subsurface hydrologic processes. A possible application includes the identification of capillary fringes in the vadose zone. Multiple and discontinuous water tables persist in many temperate regions, under various hydrogeologi...

  15. APPLICATION OF THE NATURALLY-OCCURRING DEUTERIUM ISOTOPE TO TRACING THE CAPILLARY FRINGE

    EPA Science Inventory

    Naturally-occurring deuterium is a useful tracer of subsurface hydrologic processes. A possible application includes the identification of capillary fringes in the vadose zone. Multiple and discontinuous water tables persist in many temperate regions, under various hydrogeologi...

  16. An experimental determination of chlorine isotope fractionation in acid systems and applications to volcanic fumaroles

    NASA Astrophysics Data System (ADS)

    Sharp, Z. D.; Barnes, J. D.; Fischer, T. P.; Halick, M.

    2010-01-01

    The δ 37Cl values of volcanic fumarole gases and bubbling springs were measured from the Central American and the Kurile arcs. Low temperature gas samples from the Central American arc have δ 37Cl values generally between -2 and 2‰, whereas high-temperature fumaroles (>100 °C) range from 4 to 12‰, with several outliers. This is in contrast to the high-temperature fumaroles from the Kurile island Kudryavy which have slightly positive δ 37Cl values, averaging 0.8‰ (±0.6, 1σ), and from our previous work on Izu and Mariana arc samples in which the δ 37Cl values of fumarole and ash samples are similar to each other and negative. Assuming that the source for the high-T Central American fumaroles has typical subduction δ 37Cl values (-2.5 to 1‰), then there must be a large Cl isotope fractionation in the near-surface fumarolic system. The most likely fractionation mechanism for the high δ 37Cl values is between Cl -aq - HCl( g), but published theoretical fractionation for this pair is only ˜1.5‰, insufficient to explain the large range of values observed in the fumaroles. Three experiments were undertaken in order to identify a process that could cause the wide range of δ 37Cl values observed in the high-temperature fumaroles. Results are the following: (1) A sub-boiling equilibration experiment between aqueous chloride and HCl gas had 1000lnα=1.4to1.8‰, in agreement with the theoretical calculations. (2) Evaporation of HCl( g) from hydrochloric acid at room temperature had fractionation in the opposite sense, with a 1000lnα=-3.92‰. (3) A 'synthetic fumarole' gave large positive fractionations up to 9‰, with 37Cl strongly partitioned into the vapor phase. The 'fumarole' experiments were made by bubbling dry air through boiling hydrochloric acid in an Erlenmeyer flask, and collecting the evolved HCl( g) in a second 'downstream' flask filled with distilled water. This extreme enrichment is likely due to a distillation process in which 37Cl

  17. Application of SAIL phenylalanine and tyrosine with alternative isotope-labeling patterns for protein structure determination.

    PubMed

    Takeda, Mitsuhiro; Ono, Akira M; Terauchi, Tsutomu; Kainosho, Masatsune

    2010-01-01

    The extensive collection of NOE constraint data involving the aromatic ring signals is essential for accurate protein structure determination, although it is often hampered in practice by the pervasive signal overlapping and tight spin couplings for aromatic rings. We have prepared various types of stereo-array isotope labeled phenylalanines (epsilon- and zeta-SAIL Phe) and tyrosine (epsilon-SAIL Tyr) to overcome these problems (Torizawa et al. 2005), and proven that these SAIL amino acids provide dramatic spectral simplification and sensitivity enhancement for the aromatic ring NMR signals. In addition to these SAIL aromatic amino acids, we recently synthesized delta-SAIL Phe and delta-SAIL Tyr, which allow us to observe and assign delta-(13)C/(1)H signals very efficiently. Each of the various types of SAIL Phe and SAIL Tyr yields well-resolved resonances for the delta-, epsilon- or zeta-(13)C/(1)H signals, respectively, which can readily be assigned by simple and robust pulse sequences. Since the delta-, epsilon-, and zeta-proton signals of Phe/Tyr residues give rise to complementary NOE constraints, the concomitant use of various types of SAIL-Phe and SAIL-Tyr would generate more accurate protein structures, as compared to those obtained by using conventional uniformly (13)C, (15)N-double labeled proteins. We illustrated this with the case of an 18.2 kDa protein, Escherichia coli peptidyl-prolyl cis-trans isomerase b (EPPIb), and concluded that the combined use of zeta-SAIL Phe and epsilon-SAIL Tyr would be practically the best choice for protein structural determinations.

  18. Applications of the 190Pt-186Os isotope system to geochemistry and cosmochemistry

    USGS Publications Warehouse

    Walker, R.J.; Morgan, J.W.; Beary, E.S.; Smoliar, M.I.; Czamanske, G.K.; Horan, M.F.

    1997-01-01

    Platinum is fractionated from osmium primarily as a consequence of processes involving sulfide and metal crystallization. Consequently, the 190Pt-186Os isotope system (190Pt ??? 186Os + ??) shows promise for dating some types of magmatic sulfide ores and evolved iron meteorites. The first 190Pt-186Os isochrons are presented here for ores from the ca. 251 Ma Noril'sk, Siberia plume, and for group IIAB magmatic iron meteorites. Given the known age of the Noril'sk system, a decay constant for 190Pt is determined to be 1.542 ?? 10-12a-1, with ??1% uncertainty. The isochron generated for the IIAB irons is consistent with this decay constant and the known age of the group. The 186Os/188Os ratios of presumably young, mantle-derived osmiridiums and also the carbonaceous chondrite Allende were measured to high-precision to constrain the composition of the modern upper mantle. These compositions overlap, indicating that the upper mantle is chondritic within the level of resolution now available. Our best estimate for this 186Os/188Os ratio is 0.119834 ?? 2 (2??M). The 190Pt/186Os ratios determined for six enstatite chondrites average 0.001659 ?? 75, which is very similar to published values for carbonaceous chondrites. Using this ratio and the presumed composition of the modern upper mantle and chondrites, a solar system initial 186Os/188Os ratio of 0.119820 is calculated. In comparison to the modern upper mantle composition, the 186Os/188Os ratio of the Noril'sk plume was approximately 0.012% enriched in 186Os. Possible reasons for this heterogeneity include the recycling of Pt-rich crust into the mantle source of the plume and derivation of the osmium from the outer core. Derivation of the osmium from the outer core is our favored model. Copyright ?? 1997 Elsevier Science Ltd.

  19. Application of Uncertainty in Measurement (GUM) to Isotope Mass Spectrometry: Introduction, Implemention, and Examples

    NASA Astrophysics Data System (ADS)

    Buerger, S.; Essex, R. M.; Mathew, K. J.; Thomas, R. B.

    2008-12-01

    As the measured value and its unit are integral parts of a measurement, so is a statement of the associated measurement uncertainty. The importance of providing an uncertainty that can reasonably be attributed to the measured value is often underrated. An assessment of uncertainty provides confidence in the value of the measurement, judgement on significance of differences between measurement results, information regarding the capability of the measurement procedure, and quality assurance. The limitations of the classical error analysis were seen as a hindrance to communication of scientific and technical measurement results, initiating the development of the Guide to the Expression of Uncertainty in Measurement (GUM) in the late 1970s. Just as the use of the International System of Units brings coherence to measurements, the International Organization for Standardization Guide to the Expression of Uncertainty in Measurement recommends a standardized way of expressing uncertainty in all kinds of measurements. Consequently, GUM has been adopted by most of the national metrology institutes in the world. A short introduction to GUM and the logical steps leading to its development will be presented, as well as a comparison between classical error analysis and GUM. Examples related to mass spectrometry for isotopic and elemental analysis will be discussed. The merits of GUM - transparency of the uncertainty evaluation, the treatment of uncertainties in a consistent logical way, and the presentation of an uncertainty budget resulting in a feedback to the analyst (i.e. identifies the dominant components of uncertainty and allows better understanding and improvement of the measurement process) - will be emphasised.

  20. Development of laser ablation multi-collector inductively coupled plasma mass spectrometry for boron isotopic measurement in marine biocarbonates: new improvements and application to a modern Porites coral.

    PubMed

    Thil, François; Blamart, Dominique; Assailly, Caroline; Lazareth, Claire E; Leblanc, Thierry; Butsher, John; Douville, Eric

    2016-02-15

    Laser Ablation coupled to Multi-Collector Inductively Coupled Plasma Mass Spectrometry (LA-MC-ICPMS) is a powerful tool for the high-precision measurement of the isotopic ratios of many elements in geological samples, with the isotope ratio ((11) B/(10) B) of boron being used as an indicator of the pH of oceanic waters. Most geological samples or standards are polished and ablation occurs on flat surfaces. However, the shape and the irregularities of marine biocarbonates (e.g., corals, foraminifera) can make precise isotopic measurements of boron difficult. Even after polishing, the porosity properties and the presence of holes or micro-fractures affect the signal and the isotopic ratio when ablating the material, especially in raster mode. The effect of porosity and of the crater itself on the (11) B signal and the isotopic ratio acquired by LA-MC-ICPMS in both raster and spot mode was studied. Characterization of the craters was then performed with an optical profilometer to determine their shapes and depths. Surface state effects were examined by analyzing the isotopic fractionation of boron in silicate (NIST-SRM 612 and 610 standards) and in carbonate (corals). Surface irregularities led to a considerable loss of signal when the crater depth exceeded 20 µm. The stability and precision were degraded when ablation occurred in a deep cavity. The effect of laser focusing and of blank correction was also highlighted and our observations indicate that the accuracy of the boron isotopic ratio does not depend on the shape of the surface. After validation of the analytical protocol for boron isotopes, a raster application on a Porites coral, which grew for 18 months in an aquarium after field sampling, was carried out. This original LA-MC-ICPMS study revealed a well-marked boron isotope ratio temporal variability, probably related to growth rate and density changes, irrespective of the pH of the surrounding seawater. Copyright © 2015 John Wiley & Sons, Ltd. Copyright

  1. Isotopic analysis of methane by Cavity Ringdown Spectroscopy (CRDS) Application to the deep-sea Congolobe fan

    NASA Astrophysics Data System (ADS)

    Caprais, J.; Cathalot, C.; de Prunelé, A.; Ruffine, L.; Cassarino, L.; Le Bruchec, J.; Olu, K.; Rabouille, C.

    2013-12-01

    Channeling all the continental material exported from the Congo River to the terminal lobes, the Congo deep-sea fan constitutes an unrecognized hotspot for biology and biogeochemistry in the Atlantic Ocean. Assemblages of benthic ecosystems in this peculiar environment mimic the ones observed only in active cold-seep regions. Massive organic matter inputs from the Congo canyon likely induce a sedimentary production of reduced fluids bearing sulphide and methane. These reduced compounds may support the development of bacterial mats based on chemo-autotrophy and the presence of biological communities feeding on these mats, as already observed in sediment from the lobe zone. Yet, the processes and driving forces controlling the structure of benthic communities in the lobe of the Congo submarine canyon are still poorly understood. Isotopic fractionations occurring during methanogenesis (depletion), thermic alteration of organic matter (enrichment), and microbial anaerobic oxidation (enrichment) lead to distinct δ13CH4 signatures 1,2. Hence, stable methane isotopes are increasingly being used to determine methane source in the surrounding sediments and infer the gas provenance 3. In the frame of the Congolobe project, this study investigates the functioning of benthic communities in relation with the main environmental conditions. Specifically, it focuses on the applicability of the stable methane isotopes (δ13CH4) in understanding the sediment processes involved and the metabolism of the benthic ecosystems (chemo-autotrophy vs heterotrophy). A total of 5 sites (A, B, C, E, F) were investigated, at a water depth of approximately 5000 m. Three sites (A,F,C) were located along the main axis of the currently active lobe. Site B was located on a lobe which has been disconnected from the active canyon for several decades. Site E corresponds to a fossil lobe, and is taken as a reference station for hemipelagic deposition. At site C, sediment cores of ~20 cm length were

  2. Digitally enhanced thin layer chromatography: further development and some applications in isotopic chemistry.

    PubMed

    Manthorpe, Daniel P; Lockley, William J S

    2013-09-01

    Improvements to thin layer chromatography (TLC) analysis can be made easily and cheaply by the application of digital colour photography and image analysis. The combined technique, digitally enhanced TLC (DE-TLC), is applicable to the accurate quantification of analytes in mixtures, to reaction monitoring and to other typical uses of TLC. Examples are given of the application of digitally enhanced TLC to: the deuteromethylations of theophylline to [methyl-(2)H3]caffeine and of umbelliferone to [(2)H3]7-methoxycoumarin; the selection of tertiary amine bases in deuterodechlorination reactions; stoichiometry optimisation in the borodeuteride reduction of quinizarin (1,4-dihydroxyanthraquinone) and to the assessment of xanthophyll yields in Lepidium sativum seedlings grown in deuterated media. Copyright © 2013 John Wiley & Sons, Ltd.

  3. An integrated spatial snap-shot monitoring method for identifying seasonal changes and spatial changes in surface water quality

    NASA Astrophysics Data System (ADS)

    Chittoor Viswanathan, Vidhya; Jiang, Yongjun; Berg, Michael; Hunkeler, Daniel; Schirmer, Mario

    2016-08-01

    Integrated catchment-scale management approaches in large catchments are often hindered due to the poor understanding of the spatially and seasonally variable pathways of pollutants. High-frequency monitoring of water quality at random locations in a catchment is resource intensive and challenging. A simplified catchment-scale monitoring approach is developed in this study, for the preliminary identification of water quality changes - Integrated spatial snap-shot monitoring (ISSM). This multi-parameter monitoring approach is applied using the isotopes of water (δ18O-H2O and δD) and nitrate (δ15N-NO3- and δ18O-NO3-) together with the fluxes of nitrate and other solutes, which are used as chemical markers. This method involves selection of few sampling stations, which are identified as the hotspots of water quality changes within the catchment. The study was conducted in the peri-alpine Thur catchment in Switzerland, with two snap-shot campaigns (representative of two widely varying hydrological conditions), in summer 2012 (low flow) and spring 2013 (high flow). Significant spatial (varying with elevation) and seasonal changes in the sources of water were observed between the two seasons. A spatial variation of the sources of nitrate and the solute loads was observed, in tandem with the land use changes in the Thur catchment. There is a seasonal shift in the sources of nitrate, it varies from a strong treated waste water signature during the low flow season to a mixture of other sources (like soil nitrogen derived from agriculture), in the high flow season. This demonstrates the influence of other sources that override the influence of waste water treatment plants (WWTPs) during high flow in the Thur River and its tributaries. This method is expected to be a cost-effective alternative, providing snap-shots, that can help in the preliminary identification of the pathways of solutes and their seasonal/spatial changes in catchments.

  4. Application of copper vapour lasers for controlling activity of uranium isotopes

    SciTech Connect

    Barmina, E V; Sukhov, I A; Lepekhin, N M; Priseko, Yu S; Filippov, V G; Simakin, Aleksandr V; Shafeev, Georgii A

    2013-06-30

    Beryllium nanoparticles are generated upon ablation of a beryllium target in water by a copper vapour laser. The average size of single crystalline nanoparticles is 12 nm. Ablation of a beryllium target in aqueous solutions of uranyl chloride leads to a significant (up to 50 %) decrease in the gamma activity of radionuclides of the uranium-238 and uranium-235 series. Data on the recovery of the gamma activity of these nuclides to new steady-state values after laser irradiation are obtained. The possibility of application of copper vapour lasers for radioactive waste deactivation is discussed. (laser applications and other topics in quantum electronics)

  5. Negative correlation between altitudes and oxygen isotope ratios of seeds: exploring its applicability to assess vertical seed dispersal.

    PubMed

    Naoe, Shoji; Tayasu, Ichiro; Masaki, Takashi; Koike, Shinsuke

    2016-10-01

    Vertical seed dispersal, which plays a key role in plant escape and/or expansion under climate change, was recently evaluated for the first time using negative correlation between altitudes and oxygen isotope ratio of seeds. Although this method is innovative, its applicability to other plants is unknown. To explore the applicability of the method, we regressed altitudes on δ(18)O of seeds of five woody species constituting three families in temperate forests in central Japan. Because climatic factors, including temperature and precipitation that influence δ(18)O of plant materials, demonstrate intensive seasonal fluctuation in the temperate zone, we also evaluated the effect of fruiting season of each species on δ(18)O of seeds using generalized linear mixed models (GLMM). Negative correlation between altitudes and δ(18)O of seeds was found in four of five species tested. The slope of regression lines tended to be lower in late-fruiting species. The GLMM analysis revealed that altitudes and date of fruiting peak negatively affected δ(18)O of seeds. These results indicate that the estimation of vertical seed dispersal using δ(18)O of seeds can be applicable for various species, not just confined to specific taxa, by identifying the altitudes of plants that produced seeds. The results also suggest that the regression line between altitudes and δ(18)O of seeds is rather species specific and that vertical seed dispersal in late-fruiting species is estimated at a low resolution due to their small regression slopes. A future study on the identification of environmental factors and plant traits that cause a difference in δ(18)O of seeds, combined with an improvement of analysis, will lead to effective evaluation of vertical seed dispersal in various species and thereby promote our understanding about the mechanism and ecological functions of vertical seed dispersal.

  6. Application of non-lethal stable isotope analysis to assess feeding patterns of juvenile pallid sturgeon Scaphirhynchus albus: a comparison of tissue types and sample preservation methods

    USGS Publications Warehouse

    Andvik, R.T.; VanDeHey, J.A.; Fincel, M.J.; French, William E.; Bertrand, K.N.; Chipps, Steven R.; Klumb, R.A.; Graeb, B.D.S.

    2010-01-01

    Traditional techniques for stable isotope analysis (SIA) generally require sacrificing animals to collect tissue samples; this can be problematic when studying diets of endangered species such as the pallid sturgeon Scaphirhynchus albus. Our objectives were to (i) determine if pectoral fin tissue (non-lethal) could be a substitute for muscle tissue (lethal) in SIA of juvenile pallid sturgeon, and (ii) evaluate the influence of preservation techniques on stable isotope values. In the laboratory, individual juvenile pallid sturgeon were held for up to 186 day and fed chironomids, fish, or a commercially available pellet diet. Significant, positive relationships (r² ≥ 0.8) were observed between fin and muscle tissues for both δ15N and δ13C; in all samples isotopes were enriched in fins compared to muscle tissue. Chironomid and fish based diets of juvenile pallid sturgeon were distinguishable for fast growing fish (0.3 mm day−1) using stable δ15N and δ13C isotopes. Frozen and preserved fin tissue δ15N isotopes were strongly related (r2 = 0.89) but δ13C isotopes were weakly related (r2 = 0.16). Therefore, freezing is recommended for preservation of fin clips to avoid the confounding effect of enrichment by ethanol. This study demonstrates the utility of a non-lethal technique to assess time integrated food habits of juvenile pallid sturgeon and should be applicable to other threatened or endangered species.

  7. 78 FR 63501 - Request To Submit a Two-Part Application-Northwest Medical Isotopes, LLC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-24

    ...'' and then select ``Begin Web- based ADAMS Search.'' For problems with ADAMS, please contact the NRC's... submit its application in two parts, as described above; however, based on the current language of 10 CFR... domestic supply of Mo-99. Furthermore, when the rule was originally written, there was a ``deep national...

  8. Single snapshot multiple frequency modulated imaging of subsurface optical properties of turbid media with structured light

    NASA Astrophysics Data System (ADS)

    Xu, M.; Cao, Zili; Lin, Weihao; Chen, Xinlin; Zheng, Longfei; Zeng, Bixin

    2016-12-01

    We report a novel demodulation method that enables single snapshot wide field imaging of optical properties of turbid media in the Spatial Frequency Domain (SFD). This Single Snapshot Multiple frequency Demodulation (SSMD) method makes use of the orthogonality of harmonic functions to extract the modulation transfer function (MTF) at multiple modulation frequencies simultaneously from a single structured-illuminated image at once. The orientation, frequency, and amplitude of each modulation can be set arbitrarily subject to the limitation of the implementation device. We first validate and compare SSMD to the existing demodulation methods by numerical simulations. The performance of SSMD is then demonstrated with experiments on both tissue mimicking phantoms and in vivo for recovering optical properties by comparing to the standard three-phase demodulation approach. The results show that SSMD increases significantly the data acquisition speed and reduces motion artefacts. SSMD exhibits excellent noise suppression in imaging as well at the rate proportional to the square root of the number of pixels contained in its kernel. SSMD is ideal in the implementation of a real-time spatial frequency domain imaging platform and will open up SFDI for vast applications in imaging and monitoring dynamic turbid medium and processes.

  9. Imaging of blood cells based on snapshot Hyper-Spectral Imaging systems

    NASA Astrophysics Data System (ADS)

    Robison, Christopher J.; Kolanko, Christopher; Bourlai, Thirimachos; Dawson, Jeremy M.

    2015-05-01

    Snapshot Hyper-Spectral imaging systems are capable of capturing several spectral bands simultaneously, offering coregistered images of a target. With appropriate optics, these systems are potentially able to image blood cells in vivo as they flow through a vessel, eliminating the need for a blood draw and sample staining. Our group has evaluated the capability of a commercial Snapshot Hyper-Spectral imaging system, the Arrow system from Rebellion Photonics, in differentiating between white and red blood cells on unstained blood smear slides. We evaluated the imaging capabilities of this hyperspectral camera; attached to a microscope at varying objective powers and illumination intensity. Hyperspectral data consisting of 25, 443x313 hyperspectral bands with ~3nm spacing were captured over the range of 419 to 494nm. Open-source hyper-spectral data cube analysis tools, used primarily in Geographic Information Systems (GIS) applications, indicate that white blood cells features are most prominent in the 428-442nm band for blood samples viewed under 20x and 50x magnification over a varying range of illumination intensities. These images could potentially be used in subsequent automated white blood cell segmentation and counting algorithms for performing in vivo white blood cell counting.

  10. Application of digital sampling techniques to a "single chip telescope" for isotopic particle identification

    NASA Astrophysics Data System (ADS)

    Bardelli, L.; Poggi, G.; Bini, M.; Pasquali, G.; Taccetti, N.

    2004-12-01

    Some applications of digital sampling techniques are presented which can simplify experiments involving sub-nanosecond timing determinations and energy measurements with nuclear detectors used for Pulse Shape Analysis and Time of Flight measurements in heavy ion experiments. The basic principles of the method are discussed as well as the main parameters that influence the accuracy of the measurements. The method allows to obtain both high resolution time and amplitude information with an electronic chain simply consisting of a charge preamplifier and a fast high resolution ADC (in the present application: 100 MSample/s, 12 bit) coupled to an efficient on-line software: for example the timing resolution can be as good as 100 ps FWHM. Examples of this technique applied to various detectors in heavy-ion experiments involving particle identification via Pulse Shape Analysis (PSA) are presented. Particular attention is devoted to the analysis of the performance of a "Single Chip Telescope" detector coupled to such a sampling system.

  11. Stable Carbon Isotopes (δ 13C) in Coral Skeletons: Experimental Approach and Applications for Paleoceanography

    NASA Astrophysics Data System (ADS)

    Grottoli, A. G.

    2004-12-01

    natural field conditions corals feed on zooplankton below this `nutrient threshold' and that increases in heterotrophy should result in decreases skeletal δ 13C values. Overall, changes in photosynthesis and heterotrophy have significant effects on coral skeletal δ 13C. In shallower corals, photosynthesis drives the bulk of the variation in δ 13C. In addition, boron isotope data indicate that pH levels do not vary with changes in photosynthesis or heterotrophy suggesting that metabolically driven δ 13C fractionation during skeletogenesis is not pH driven. Thus the skeletal δ 13C records from shallow corals in non-upwelling regions where zooplankton concentrations are relatively constant should represent a reliable proxy of light variability. Due to the complexity associated with nutrients and heterotrophy, δ 13C records from upwelling regions or deep corals are still difficult to resolve.

  12. Silicon isotopic abundance toward evolved stars and its application for presolar grains

    NASA Astrophysics Data System (ADS)

    Peng, T.-C.; Humphreys, E. M. L.; Testi, L.; Baudry, A.; Wittkowski, M.; Rawlings, M. G.; de Gregorio-Monsalvo, I.; Vlemmings, W.; Nyman, L.-A.; Gray, M. D.; de Breuck, C.

    2013-11-01

    Aims: Galactic chemical evolution (GCE) is important for understanding the composition of the present-day interstellar medium (ISM) and of our solar system. In this paper, we aim to track the GCE by using the 29Si/30Si ratios in evolved stars and tentatively relate this to presolar grain composition. Methods: We used the APEX telescope to detect thermal SiO isotopologue emission toward four oxygen-rich M-type stars. Together with the data retrieved from the Herschel science archive and from the literature, we were able to obtain the 29Si/30Si ratios for a total of 15 evolved stars inferred from their optically thin 29SiO and 30SiO emission. These stars cover a range of masses and ages, and because they do not significantly alter 29Si/30Si during their lifetimes, they provide excellent probes of the ISM metallicity (or 29Si/30Si ratio) as a function of time. Results: The 29Si/30Si ratios inferred from the thermal SiO emission tend to be lower toward low-mass oxygen-rich stars (e.g., down to about unity for W Hya), and close to an interstellar or solar value of 1.5 for the higher-mass carbon star IRC+10216 and two red supergiants. There is a tentative correlation between the 29Si/30Si ratios and the mass-loss rates of evolved stars, where we take the mass-loss rate as a proxy for the initial stellar mass or current stellar age. This is consistent with the different abundance ratios found in presolar grains. Before the formation of the Sun, the presolar grains indicate that the bulk of presolar grains already had 29Si/30Si ratios of about 1.5, which is also the ratio we found for the objects younger than the Sun, such as VY CMa and IRC+10216. However, we found that older objects (up to possibly 10 Gyr old) in our sample trace a previous, lower 29Si/30Si value of about 1. Material with this isotopic ratio is present in two subclasses of presolar grains, providing independent evidence of the lower ratio. Therefore, the 29Si/30Si ratio derived from the SiO emission of

  13. Serial snapshot crystallography for materials science with SwissFEL

    SciTech Connect

    Dejoie, Catherine; Smeets, Stef; Baerlocher, Christian; Tamura, Nobumichi; Pattison, Philip; Abela, Rafael; McCusker, Lynne B.

    2015-04-21

    New opportunities for studying (sub)microcrystalline materials with small unit cells, both organic and inorganic, will open up when the X-ray free electron laser (XFEL) presently being constructed in Switzerland (SwissFEL) comes online in 2017. Our synchrotron-based experiments mimicking the 4%-energy-bandpass mode of the SwissFEL beam show that it will be possible to record a diffraction pattern of up to 10 randomly oriented crystals in a single snapshot, to index the resulting reflections, and to extract their intensities reliably. The crystals are destroyed with each XFEL pulse, but by combining snapshots from several sets of crystals, a complete set of data can be assembled, and crystal structures of materials that are difficult to analyze otherwise will become accessible. Even with a single shot, at least a partial analysis of the crystal structure will be possible, and with 10–50 femtosecond pulses, this offers tantalizing possibilities for time-resolved studies.

  14. 12. Photographic copy of historic photograph. Original snapshot print can ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. Photographic copy of historic photograph. Original snapshot print can be found in narrative reports of the Lower Souris Migratory Waterfowl Refuge for the 1930s, on file at the headquarters of the J. Clark Salyer National Wildlife Refuge, Upham, North Dakota. GATES OF DAM 320 ON APRIL 9, 1936 WITH ICE ON WATER 50 INCHES THICK - J. Clark Salyer National Wildlife Refuge, Dam 320, Along Lower Souris River, Kramer, Bottineau County, ND

  15. 5. Photographic copy of historic photography. Original snapshot print is ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. Photographic copy of historic photography. Original snapshot print is in narrative reports of the Lower Souris Migratory Waterfowl Refuge for the 1930s, on file at the headquarters of the J. Clark Salyer National Wildlife Refuge, Upham, North Dakota. DREDGING CHANNEL FOR THE SOURIS RIVER FOR DRAINAGE PURPOSES IN THE EARLY 20TH CENTURY - J. Clark Salyer National Wildlife Refuge Dams, Along Lower Souris River, Kramer, Bottineau County, ND

  16. SnapShot: Nucleic acid immune sensors, part 2.

    PubMed

    Hornung, Veit

    2014-12-18

    The innate immune system has evolved sensors that can detect specific molecular fingerprints of non-self RNA or DNA. At the same time, some receptors respond to nucleic acids of both exogenous and endogenous origin, yet they are spatially segregated from endogenous nucleic acids. This SnapShot schematizes families and individual members of nucleic acid sensors with a focus on their ligands and the signaling pathways they employ.

  17. SnapShot: Hormones of the gastrointestinal tract.

    PubMed

    Coate, Katie C; Kliewer, Steven A; Mangelsdorf, David J

    2014-12-04

    Specialized endocrine cells secrete a variety of peptide hormones all along the gastrointestinal (GI) tract, making it one of the largest endocrine organs in the body. Nutrients and developmental and neural cues trigger the secretion of gastrointestinal (GI) hormones from specialized endocrine cells along the GI tract. These hormones act in target tissues to facilitate digestion and regulate energy homeostasis. This SnapShot summarizes the production and functions of GI hormones. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. [Diagnostic efficiency on digital snapshots of the standard radiology imaging].

    PubMed

    Campanella, Nando; Antico, Ettore; Dini, Leonardo; Morosini, Pierpaolo

    2004-12-01

    The authors had experienced the telediagnosis on digital snapshots of standard radiology imaging (chest, abdomen, and bones), sent by e-mailing, to support the medical doctors working in remote areas of developing countries. In order to validate the overall procedure, the authors have set up a simulating model and estimated some parameters of accuracy of the diagnosis on digital snapshots against the golden standard of the diagnosis by direct look. The study concerned the standard X-ray tests of one hundred randomly-selected patients out of a hospital archive. Four years later the diagnosis by direct look, the team of radiologists carried out the blind cross check on the digital snapshots of the radiograms and stated their second diagnosis. Sensibility, specificity, predictive value of positives, predictive value of negatives and efficiency of the whole series have been 83.0, 95.1, 96.1, 79.6 and 88.0%. By breaking up the series by apparatus, the skeleton test shows similar data of the whole series. The chest test shows a specificity and predictive value of positives of 100.0%. Although the number of cases is low, the abdomen test apparently shows a sensibility and predictive value of negatives as high as 100%, but a lower specificity and predictive value of negatives (85.7 and 87.5%). Though this data is supportive to the validation of the procedure, even better results are supposedly achieved by increasing the quality of the snapshots and by improving the skills of using the software.

  19. Snapshot RGB mapping of skin melanin and hemoglobin

    NASA Astrophysics Data System (ADS)

    Spigulis, Janis; Oshina, Ilze

    2015-05-01

    The concept of snapshot red-green-blue (RGB) multispectral imaging was applied for skin chromophore mapping. Three monochromatic spectral images have been extracted from a single RGB image dataset at simultaneous illumination of skin by 473-, 532-, and 659-nm laser lines. The spectral images were further transformed into distribution maps of skin melanin, oxyhemoglobin, and deoxyhemoglobin, related to pigmented and vascular skin malformations. The performance and clinical potential of the proposed technique are discussed.

  20. SnapShot: CRISPR-RNA-guided adaptive immune systems.

    PubMed

    Carter, Joshua; Wiedenheft, Blake

    2015-09-24

    Bacteria and archaea have evolved sophisticated adaptive immune systems that reply on CRISPR loci and a diverse cassette of Cas genes that are classified into three main types and at least eleven subtypes. All CRISPR-Cas immune systems operate through three main stages: acquisition, biogenesis, and interference. This SnapShot summarizes our current knowledge of these fascinating immune systems. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Hydrogen isotope correction for laser instrument measurement bias at low water vapor concentration using conventional isotope analyses: application to measurements from Mauna Loa Observatory, Hawaii.

    PubMed

    Johnson, L R; Sharp, Z D; Galewsky, J; Strong, M; Van Pelt, A D; Dong, F; Noone, D

    2011-03-15

    The hydrogen and oxygen isotope ratios of water vapor can be measured with commercially available laser spectroscopy analyzers in real time. Operation of the laser systems in relatively dry air is difficult because measurements are non-linear as a function of humidity at low water concentrations. Here we use field-based sampling coupled with traditional mass spectrometry techniques for assessing linearity and calibrating laser spectroscopy systems at low water vapor concentrations. Air samples are collected in an evacuated 2 L glass flask and the water is separated from the non-condensable gases cryogenically. Approximately 2 µL of water are reduced to H(2) gas and measured on an isotope ratio mass spectrometer. In a field experiment at the Mauna Loa Observatory (MLO), we ran Picarro and Los Gatos Research (LGR) laser analyzers for a period of 25 days in addition to periodic sample collection in evacuated flasks. When the two laser systems are corrected to the flask data, they are strongly coincident over the entire 25 days. The δ(2)H values were found to change by over 200‰ over 2.5 min as the boundary layer elevation changed relative to MLO. The δ(2)H values ranged from -106 to -332‰, and the δ(18)O values (uncorrected) ranged from -12 to -50‰. Raw data from laser analyzers in environments with low water vapor concentrations can be normalized to the international V-SMOW scale by calibration to the flask data measured conventionally. Bias correction is especially critical for the accurate determination of deuterium excess in dry air.

  2. Unexpectedly high degree of anammox and DNRA in seagrass sediments: Description and application of a revised isotope pairing technique

    NASA Astrophysics Data System (ADS)

    Salk, Kateri R.; Erler, Dirk V.; Eyre, Bradley D.; Carlson-Perret, Natasha; Ostrom, Nathaniel E.

    2017-08-01

    Understanding the magnitude of nitrogen (N) loss and recycling pathways is crucial for coastal N management efforts. However, quantification of denitrification and anammox by a widely-used method, the isotope pairing technique, is challenged when dissimilatory NO3- reduction to NH4+ (DNRA) occurs. In this study, we describe a revised isotope pairing technique that accounts for the influence of DNRA on NO3- reduction (R-IPT-DNRA). The new calculation procedure improves on previous techniques by (1) accounting for N2O production, (2) distinguishing canonical anammox from coupled DNRA-anammox, and (3) including the production of 30N2 by anammox in the quantification of DNRA. This approach avoids the potential for substantial underestimates of anammox rates and overestimates of denitrification rates in systems where DNRA is a significant NO3- reduction pathway. We apply this technique to simultaneously quantify rates of anammox, denitrification, and DNRA in intact sediments adjacent to a seagrass bed in subtropical Australia. The effect of organic carbon lability on NO3- reduction was also addressed by adding detrital sources with differing C:N (phytoplankton- or seagrass-derived). DNRA was the predominant pathway, contributing 49-74% of total NO3- reduction (mean 0.42 μmol N m-2 h-1). In this high C:N system, DNRA outcompetes denitrification for NO3-, functioning to recycle rather than remove N. Anammox exceeded denitrification (mean 0.18 and 0.04 μmol N m-2 h-1, respectively) and accounted for 64-86% of N loss, a rare high percentage in shallow coastal environments. Owing to low denitrification activity, N2O production was ∼100-fold lower than in other coastal sediments (mean 7.7 nmol N m-2 h-1). All NO3- reduction pathways were stimulated by seagrass detritus but not by phytoplankton detritus, suggesting this microbial community is adapted to process organic matter that is typically encountered. The R-IPT-DNRA is widely applicable in other environments where the

  3. Application of iron and zinc isotopes to track the sources and mechanisms of metal loading in a mountain watershed

    USGS Publications Warehouse

    Borrok, D.M.; Wanty, R.B.; Ian, Ridley W.; Lamothe, P.J.; Kimball, B.A.; Verplanck, P.L.; Runkel, R.L.

    2009-01-01

    Here the hydrogeochemical constraints of a tracer dilution study are combined with Fe and Zn isotopic measurements to pinpoint metal loading sources and attenuation mechanisms in an alpine watershed impacted by acid mine drainage. In the tested mountain catchment, ??56Fe and ??66Zn isotopic signatures of filtered stream water samples varied by ???3.5??? and 0.4???, respectively. The inherent differences in the aqueous geochemistry of Fe and Zn provided complimentary isotopic information. For example, variations in ??56Fe were linked to redox and precipitation reactions occurring in the stream, while changes in ??66Zn were indicative of conservative mixing of different Zn sources. Fen environments contributed distinctively light dissolved Fe (<-2.0???) and isotopically heavy suspended Fe precipitates to the watershed, while Zn from the fen was isotopically heavy (>+0.4???). Acidic drainage from mine wastes contributed heavier dissolved Fe (???+0.5???) and lighter Zn (???+0.2???) isotopes relative to the fen. Upwelling of Fe-rich groundwater near the mouth of the catchment was the major source of Fe (??56Fe ??? 0???) leaving the watershed in surface flow, while runoff from mining wastes was the major source of Zn. The results suggest that given a strong framework for interpretation, Fe and Zn isotopes are useful tools for identifying and tracking metal sources and attenuation mechanisms in mountain watersheds. ?? 2009 Elsevier Ltd.

  4. Advances in Methane Isotope Measurements via Direct Absorption Spectroscopy with Applications to Oil and Gas Source Characterization

    NASA Astrophysics Data System (ADS)

    Yacovitch, T. I.; Herndon, S. C.; Roscioli, J. R.; Petron, G.; Shorter, J. H.; Jervis, D.; McManus, J. B.; Nelson, D. D.; Zahniser, M. S.; Kolb, C. E., Jr.

    2015-12-01

    Instrumental developments in the measurement of multiple isotopes of methane (12CH4, 13CH4 and 12CH3D) are presented. A first generation 8-micron instrument quantifies 12CH4 and 13CH4 at a 1-second rate via tunable infrared direct absorption spectroscopy (TILDAS). A second generation instrument uses two 3-micron intraband cascade lasers in an Aerodyne dual laser chassis for simultaneous measurement of 12CH4, 13CH4 and 12CH3D. Sensitivity and noise performance improvements are examined. The isotopic signature of methane provides valuable information for emission source identification of this greenhouse gas. A first generation spectrometer has been deployed in the field on a mobile laboratory along with a sophisticated 4-tank calibration system. Calibrations are done on an agressive schedule, allowing for the correction of measured isotope ratios to an absolute isotope scale. Distinct isotopic signatures are found for a number of emission sources in the Denver-Julesburg Basin: oil and gas gathering stations, compressor stations and processing plants; a municipal landfill, and dairy/cattle operations. The isotopic signatures are compared with measured ethane/methane ratios. These direct absorption measurements have larger uncertainties than samples measured via gas chromatography-mass spectrometry, but have several advantages over canister sampling methods: individual sources of short duration are easier to isolate; calibrated isotope ratio results are available immediately; replicate measurements on a single source are easily performed; and the number of sources sampled is not limited by canister availability and processing time.

  5. Ab initio calculation of the Zn isotope effect in phosphates, citrates, and malates and applications to plants and soil.

    PubMed

    Fujii, Toshiyuki; Albarède, Francis

    2012-01-01

    Stable Zn isotopes are fractionated in roots and leaves of plants. Analyses demonstrate that the heavy Zn isotopes are enriched in the root system of plants with respect to shoots and leaves as well as the host soil, but the fractionation mechanisms remain unclear. Here we show that the origin of this isotope fractionation is due to a chemical isotope effect upon complexation by Zn malates and citrates in the aerial parts and by phosphates in the roots. We calculated the Zn isotope effect in aqueous citrates, malates, and phosphates by ab initio methods. For pH<5, the Zn isotopic compositions of the various parts of the plants are expected to be similar to those of groundwater. In the neutral to alkaline region, the calculations correctly predict that (66)Zn is enriched over (64)Zn in roots, which concentrate phosphates, with respect to leaves, which concentrate malates and citrates, by about one permil. It is proposed that Zn isotope fractionation represents a useful tracer of Zn availability and mobility in soils.

  6. Ab Initio Calculation of the Zn Isotope Effect in Phosphates, Citrates, and Malates and Applications to Plants and Soil

    PubMed Central

    Fujii, Toshiyuki; Albarède, Francis

    2012-01-01

    Stable Zn isotopes are fractionated in roots and leaves of plants. Analyses demonstrate that the heavy Zn isotopes are enriched in the root system of plants with respect to shoots and leaves as well as the host soil, but the fractionation mechanisms remain unclear. Here we show that the origin of this isotope fractionation is due to a chemical isotope effect upon complexation by Zn malates and citrates in the aerial parts and by phosphates in the roots. We calculated the Zn isotope effect in aqueous citrates, malates, and phosphates by ab initio methods. For pH<5, the Zn isotopic compositions of the various parts of the plants are expected to be similar to those of groundwater. In the neutral to alkaline region, the calculations correctly predict that 66Zn is enriched over 64Zn in roots, which concentrate phosphates, with respect to leaves, which concentrate malates and citrates, by about one permil. It is proposed that Zn isotope fractionation represents a useful tracer of Zn availability and mobility in soils. PMID:22363478

  7. A Snapshot of Photo Editing Options

    ERIC Educational Resources Information Center

    Bolkan, J.V.

    2004-01-01

    Plenty of digital imaging professionals claim that Adobe's Photoshop CS is the best photo editing application money can buy. This document reviews Adobe's Photoshop CS and its worthy competitors. In addition to Adobe, the following programs are reviewed in this document: (1) Adobe Photoshop Elements 2.0; (2) Arcsoft PhotoImpression; (3) Jasc Paint…

  8. Online Catalog of Isotope Products from DOE's National Isotope Development Center

    DOE Data Explorer

    The National Isotope Development Center (NIDC) interfaces with the User Community and manages the coordination of isotope production across the facilities and business operations involved in the production, sale, and distribution of isotopes. A virtual center, the NIDC is funded by the Isotope Development and Production for Research and Applications (IDPRA) subprogram of the Office of Nuclear Physics in the U.S. Department of Energy Office of Science. The Isotope subprogram supports the production, and the development of production techniques of radioactive and stable isotopes that are in short supply for research and applications. Isotopes are high-priority commodities of strategic importance for the Nation and are essential for energy, medical, and national security applications and for basic research; a goal of the program is to make critical isotopes more readily available to meet domestic U.S. needs. This subprogram is steward of the Isotope Production Facility (IPF) at Los Alamos National Laboratory (LANL), the Brookhaven Linear Isotope Producer (BLIP) facility at BNL, and hot cell facilities for processing isotopes at ORNL, BNL and LANL. The subprogram also coordinates and supports isotope production at a suite of university, national laboratory, and commercial accelerator and reactor facilities throughout the Nation to promote a reliable supply of domestic isotopes. The National Isotope Development Center (NIDC) at ORNL coordinates isotope production across the many facilities and manages the business operations of the sale and distribution of isotopes.

  9. Fertilizer nitrogen isotope signatures.

    PubMed

    Bateman, Alison S; Kelly, Simon D

    2007-09-01

    There has been considerable recent interest in the potential application of nitrogen isotope analysis in discriminating between organically and conventionally grown crops. A prerequisite of this approach is that there is a difference in the nitrogen isotope compositions of the fertilizers used in organic and conventional agriculture. We report new measurements of delta15N values for synthetic nitrogen fertilizers and present a compilation of the new data with existing literature nitrogen isotope data. Nitrogen isotope values for fertilizers that may be permitted in organic cultivation systems are also reported (manures, composts, bloodmeal, bonemeal, hoof and horn, fishmeal and seaweed based fertilizers). The delta15N values of the synthetic fertilizers in the compiled dataset fall within a narrow range close to 0 per thousand with 80% of samples lying between-2 and 2 per thousand and 98.5% of the data having delta15N values of less than 4 per thousand (mean=0.2 per thousand n=153). The fertilizers that may be permitted in organic systems have a higher mean delta15N value of 8.5 per thousand and exhibit a broader range in delta15N values from 0.6 to 36.7 per thousand (n=83). The possible application of the nitrogen isotope approach in discriminating between organically and conventionally grown crops is discussed in light of the fertilizer data presented here and with regard to other factors that are also important in determining crop nitrogen isotope values.

  10. Isotopic fractionation by diffusion in groundwater

    NASA Astrophysics Data System (ADS)

    Labolle, Eric M.; Fogg, Graham E.; Eweis, Juana B.; Gravner, Janko; Leaist, Derek G.

    2008-07-01

    During the last decade, isotopic fractionation has gained acceptance as an indicator of microbiological and chemical transformations of contaminants in groundwater. These transformation processes typically favor isotopically light, compared to isotopically heavy, contaminants, resulting in enrichment of the latter in the residual aqueous phase. In these isotope applications, it has been generally presumed that physical transport processes in groundwater have a negligible effect on isotopic enrichment. It is well known, however, that aqueous phase diffusion generally proceeds faster for isotopically light, compared to isotopically heavy, solute molecules, often resulting in isotopic fractionation in groundwater. This paper considers the potential for isotopic fractionation during transport in groundwater resulting from minute isotopic effects on aqueous diffusion coefficients. Analyses of transport in heterogeneous systems delimit the viable range of isotopic fractionation by diffusion in groundwater. Results show that diffusion can result in similar degrees of depletion and enrichment of isotopically heavy solutes during transport in heterogeneous systems with significant diffusion rate-limited mass transfer between fast- and slow-flow zones. Additional analyses and examples explore conditions that attenuate the development of significant fractionation. Examples are presented for 13C methyl tertiary butyl ether and deuterated and nondeuterated isopropanol and tertiary butyl alcohol using aqueous diffusion coefficients measured by the Taylor dispersion method with refractive index profiling as a part of this study. Examples elucidate the potential for diffusive fractionation as a confounder in isotope applications and emphasize the importance of hydrogeologic analysis for assessing the role of diffusive fractionation in isotope applications at contaminant field sites.

  11. Centrifugal enrichment of zinc isotopes, their application in medicine and in increasing radiation safety in nuclear power plants

    NASA Astrophysics Data System (ADS)

    Tcheltsov, A. N.; Sosnin, L. Yu.; Shipilov, Yu. D.; Zaozersky, Yu. P.; Khamylov, V. K.; Pochekutova, T. S.

    2006-05-01

    This paper contains the results of our research on the complete cycle of centrifuge enrichment of all zinc isotopes. The centrifuge cascade that was used to obtain the world's first zinc isotope, 70Zn, with an enrichment of more than 99.3% in gram quantities, is described. As a result of this work, gram quantities of all highly enriched zinc isotopes and hundreds of grams of depleted zinc (in the form of ZnO) with concentrations of less than 0.5% 64Zn were obtained.

  12. Isotopically controlled semiconductors

    SciTech Connect

    Haller, Eugene E.

    2006-06-19

    The following article is an edited transcript based on the Turnbull Lecture given by Eugene E. Haller at the 2005 Materials Research Society Fall Meeting in Boston on November 29, 2005. The David Turnbull Lectureship is awarded to recognize the career of a scientist who has made outstanding contributions to understanding materials phenomena and properties through research, writing, and lecturing, as exemplified by the life work of David Turnbull. Haller was named the 2005 David Turnbull Lecturer for his 'pioneering achievements and leadership in establishing the field of isotopically engineered semiconductors; for outstanding contributions to materials growth, doping and diffusion; and for excellence in lecturing, writing, and fostering international collaborations'. The scientific interest, increased availability, and technological promise of highly enriched isotopes have led to a sharp rise in the number of experimental and theoretical studies with isotopically controlled semiconductor crystals. This article reviews results obtained with isotopically controlled semiconductor bulk and thin-film heterostructures. Isotopic composition affects several properties such as phonon energies, band structure, and lattice constant in subtle, but, for their physical understanding, significant ways. Large isotope-related effects are observed for thermal conductivity in local vibrational modes of impurities and after neutron transmutation doping. Spectacularly sharp photoluminescence lines have been observed in ultrapure, isotopically enriched silicon crystals. Isotope multilayer structures are especially well suited for simultaneous self- and dopant-diffusion studies. The absence of any chemical, mechanical, or electrical driving forces makes possible the study of an ideal random-walk problem. Isotopically controlled semiconductors may find applications in quantum computing, nanoscience, and spintronics.

  13. Development of a Miniature Snapshot Multispectral Imager

    DTIC Science & Technology

    2010-09-01

    Martins, J. S.; Wolffenbuttel, R. F.; Correia, J. H. An Array of Fabry – Perot Optical – Channels for Biological Fluids Analysis. Sensors and...applications. The system is low weight and portable with a miniature platform, and requires low power. The imager uses a 4×4 Fabry - Perot filter array...shadow mask technique to fabricate a Fabry - Perot etalon with multilayer dielectric mirrors. The filter array subsystem is installed in a commercial

  14. Isotope separation

    DOEpatents

    Bartlett, Rodney J.; Morrey, John R.

    1978-01-01

    A method and apparatus is described for separating gas molecules containing one isotope of an element from gas molecules containing other isotopes of the same element in which all of the molecules of the gas are at the same electronic state in their ground state. Gas molecules in a gas stream containing one of the isotopes are selectively excited to a different electronic state while leaving the other gas molecules in their original ground state. Gas molecules containing one of the isotopes are then deflected from the other gas molecules in the stream and thus physically separated.

  15. Snapshot Imaging Spectrometry in the Visible and Long Wave Infrared

    NASA Astrophysics Data System (ADS)

    Maione, Bryan David

    Imaging spectrometry is an optical technique in which the spectral content of an object is measured at each location in space. The main advantage of this modality is that it enables characterization beyond what is possible with a conventional camera, since spectral information is generally related to the chemical composition of the object. Due to this, imaging spectrometers are often capable of detecting targets that are either morphologically inconsistent, or even under resolved. A specific class of imaging spectrometer, known as a snapshot system, seeks to measure all spatial and spectral information simultaneously, thereby rectifying artifacts associated with scanning designs, and enabling the measurement of temporally dynamic scenes. Snapshot designs are the focus of this dissertation. Three designs for snapshot imaging spectrometers are developed, each providing novel contributions to the field of imaging spectrometry. In chapter 2, the first spatially heterodyned snapshot imaging spectrometer is modeled and experimentally validated. Spatial heterodyning is a technique commonly implemented in non-imaging Fourier transform spectrometry. For Fourier transform imaging spectrometers, spatial heterodyning improves the spectral resolution trade space. Additionally, in this chapter a unique neural network based spectral calibration is developed and determined to be an improvement beyond Fourier and linear operator based techniques. Leveraging spatial heterodyning as developed in chapter 2, in chapter 3, a high spectral resolution snapshot Fourier transform imaging spectrometer, based on a Savart plate interferometer, is developed and experimentally validated. The sensor presented in this chapter is the highest spectral resolution sensor in its class. High spectral resolution enables the sensor to discriminate narrowly spaced spectral lines. The capabilities of neural networks in imaging spectrometry are further explored in this chapter. Neural networks are used to

  16. Application of stable isotope (δ13C and δ18O) composition of mollusc shells in palaeolimnological studies - possibilities and limitations

    NASA Astrophysics Data System (ADS)

    Apolinarska, Karina; Pełechaty, Mariusz; Kossler, Annette; Pronin, Eugeniusz; Noskowiak, Daria

    2017-04-01

    Carbon (δ13C) and oxygen (δ18O) stable isotope analyses are among the standard methods applied in the studies of past environment, including climate. In lacustrine sediments, δ13C and δ18O values can be measured in fine carbonate fraction (carbonate mud), in charophyte encrustations, ostracod carapaces and mollusc shells. Application of the stable isotope record of each of the above-mentioned components of the lake sediment requires knowledge about possibilities and limitations of the method. The present research discusses the most important results of the studies carried out between 2011 and 2013, concentrated on the stable isotope composition of snail shells, primarily, the species commonly preserved in central European Quaternary lacustrine sediments. The stable isotope studies involved also, the zebra mussel (Dreissena polymorpha), one of the most invasive freshwater species in the world. The research involved shell isotope studies of both recent (Apolinarska, 2013; Apolinarska et al., 2016; Apolinarska and Pełechaty, in press) and fossil molluscs derived from the Holocene sediments (Apolinarska et al., 2015a, b). Shell δ13C values were species-specific and among the gastropods studied the same order of species from the most to the least 13C-depleted was observed at all sites sampled. Shell δ18O values were more uniform. The wide range of δ13C and δ18O values were observed in population and subpopulation, i.e. when live snails were sampled live from restricted area within the lake littoral zone. Carbon and oxygen stable isotope values of the mono-specific shells sampled from 1 cm thick sediment samples were highly variable. Those intra-specific differences (n=20) were as large as several permill. Such significant variability in δ13C and δ18O values indicates that stable isotope composition of single shells is unlikely to be representative of the sediment sample. In conclusion, samples of freshwater molluscs for stable isotope analyses should be

  17. Auto-interpreter for CYP2D6 SNaPshot genotyping.

    PubMed

    Ong, Sungmoon; Jeong, Hye-Eun; Lee, Sang Seop; Shon, Ji-Hong; Shin, Jae-Gook; Kim, Eun-Young

    2008-11-06

    CYP2D6 genotyping using SNaPshot method is a very useful tool clinically. However it's hard to interpret the obtained data as a genotype without training. Thus SNaPshot auto-interpreter for the genotype was designed to interpret obtained raw data to a genotype. The auto-interpreter showed good concordance with experts' reading. The validated auto-interpreter of CYP2D6 genotyping using SNaPshot can contribute to accelerating the clinical use.

  18. Isotope Inversion Experiment evaluating the suitability of calibration in surrogate matrix for quantification via LC-MS/MS-Exemplary application for a steroid multi-method.

    PubMed

    Suhr, Anna Catharina; Vogeser, Michael; Grimm, Stefanie H

    2016-05-30

    For quotable quantitative analysis of endogenous analytes in complex biological samples by isotope dilution LC-MS/MS, the creation of appropriate calibrators is a challenge, since analyte-free authentic material is in general not available. Thus, surrogate matrices are often used to prepare calibrators and controls. However, currently employed validation protocols do not include specific experiments to verify the suitability of a surrogate matrix calibration for quantification of authentic matrix samples. The aim of the study was the development of a novel validation experiment to test whether surrogate matrix based calibrators enable correct quantification of authentic matrix samples. The key element of the novel validation experiment is the inversion of nonlabelled analytes and their stable isotope labelled (SIL) counterparts in respect to their functions, i.e. SIL compound is the analyte and nonlabelled substance is employed as internal standard. As a consequence, both surrogate and authentic matrix are analyte-free regarding SIL analytes, which allows a comparison of both matrices. We called this approach Isotope Inversion Experiment. As figure of merit we defined the accuracy of inverse quality controls in authentic matrix quantified by means of a surrogate matrix calibration curve. As a proof-of-concept application a LC-MS/MS assay addressing six corticosteroids (cortisol, cortisone, corticosterone, 11-deoxycortisol, 11-deoxycorticosterone, and 17-OH-progesterone) was chosen. The integration of the Isotope Inversion Experiment in the validation protocol for the steroid assay was successfully realized. The accuracy results of the inverse quality controls were all in all very satisfying. As a consequence the suitability of a surrogate matrix calibration for quantification of the targeted steroids in human serum as authentic matrix could be successfully demonstrated. The Isotope Inversion Experiment fills a gap in the validation process for LC-MS/MS assays

  19. 135Cs/137Cs isotopic composition of environmental samples across Europe: Environmental transport and source term emission applications

    DOE PAGES

    Snow, Mathew S.; Snyder, Darin C.

    2015-11-02

    135Cs/137Cs isotopic analyses represent an important tool for studying the fate and transport of radiocesium in the environment; in this work the 135Cs/137Cs isotopic composition in environmental samples taken from across Europe is reported. Surface soil and vegetation samples from western Russia, Ukraine, Austria, and Hungary show consistent aged thermal fission product 135Cs/137Cs isotope ratios of 0.58 ± 0.01 (age corrected to 1/1/15), with the exception of one sample of soil-moss from Hungary which shows an elevated 135Cs/137Cs ratio of 1.78 ± 0.12. With the exception of the outlier sample from Hungary, surface soil/vegetation data are in quantitative agreement withmore » values previously reported for soils within the Chernobyl exclusion zone, suggesting that radiocesium at these locations is primarily composed of homogenous airborne deposition from Chernobyl. Seawater samples taken from the Irish Sea show 135Cs/137Cs isotope ratios of 1.22 ± 0.11 (age corrected to 1/1/15), suggesting aged thermal fission product Cs discharged from Sellafield. Furthermore, the differences in 135Cs/137Cs isotope ratios between Sellafield, Chernobyl, and global nuclear weapons testing fallout indicate that 135Cs/137Cs isotope ratios can be utilized to discriminate between and track radiocesium transport from different nuclear production source terms, including major emission sources in Europe.« less

  20. (135)Cs/(137)Cs isotopic composition of environmental samples across Europe: Environmental transport and source term emission applications.

    PubMed

    Snow, Mathew S; Snyder, Darin C

    2016-01-01

    (135)Cs/(137)Cs isotopic analyses represent an important tool for studying the fate and transport of radiocesium in the environment; in this work the (135)Cs/(137)Cs isotopic composition in environmental samples taken from across Europe is reported. Surface soil and vegetation samples from western Russia, Ukraine, Austria, and Hungary show consistent aged thermal fission product (135)Cs/(137)Cs isotope ratios of 0.58 ± 0.01 (age corrected to 1/1/15), with the exception of one sample of soil-moss from Hungary which shows an elevated (135)Cs/(137)Cs ratio of 1.78 ± 0.12. With the exception of the outlier sample from Hungary, surface soil/vegetation data are in quantitative agreement with values previously reported for soils within the Chernobyl exclusion zone, suggesting that radiocesium at these locations is primarily composed of homogenous airborne deposition from Chernobyl. Seawater samples taken from the Irish Sea show (135)Cs/(137)Cs isotope ratios of 1.22 ± 0.11 (age corrected to 1/1/15), suggesting aged thermal fission product Cs discharged from Sellafield. The differences in (135)Cs/(137)Cs isotope ratios between Sellafield, Chernobyl, and global nuclear weapons testing fallout indicate that (135)Cs/(137)Cs isotope ratios can be utilized to discriminate between and track radiocesium transport from different nuclear production source terms, including major emission sources in Europe. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Production and application of high quality stable isotope-labeled human immunoglobulin G1 for mass spectrometry analysis.

    PubMed

    Phillip, Amsler; Thierry, Wolf; Christian, Lanshoeft; Anja, Bettighofer; Jochen, Eisfeld; Thomas, Moenius; Claudia, Probst; Coralie, Etter; Olivier, Heudi

    2017-03-01

    Here, we describe the production of stable isotope-labeled human immunoglobulin G1 ([(13) C]-hIgG1) using [(13) C]-L-lysine/arginine-labeled hIgG1. The fermentation process was run in shake flasks containing labeled arginine and lysinethat were incorporated into the produced recombinant hIgG1. The [(13) C]-hIgG1 was purified, and label incorporation was determined to be >99% at all lysine and arginine moieties. Sequence coverage was confirmed by peptide mapping. [(13) C]-hIgG1 was then used as an internal standard (IS) for the development of a liquid chromatography-tandem mass spectrometry method applicable to the quantitative analysis of all human types of hIgG1 in rat serum. Four conserved peptides, namely, GPSVFPLAPSSK, TTPPVLDSDGSFFLYSK, VVSVLTVLHQDWLNGK, and FNWYVDGVEVHNAK, originating from different parts of the fraction crystallizable region of hIgG1, were used for quantitation of hIgG1 in rat serum. The calibration curves with a coefficient of determination (r(2) ) between 0.9950 and 0.9962 resulting from the peak area ratio of each peptide to its respective labeled IS were reproducible. A mean bias within ±20.0% of the nominal values and a precision of ≤20.0 % were obtained for the calibration standards and quality control samples for each peptide. [(13) C]-hIgG1 was shown as a suitable IS for quantitative hIgG1 analysis in preclinical species by LC-MS/MS. Copyright © 2016 John Wiley & Sons, Ltd.

  2. Biosynthesis of 15N-labeled cylindrospermopsin and its application as internal standard in stable isotope dilution analysis.

    PubMed

    Kittler, Katrin; Hoffmann, Holger; Lindemann, Franziska; Koch, Matthias; Rohn, Sascha; Maul, Ronald

    2014-09-01

    Cylindrospermopsin (CYN) is a cyanobacterial toxin associated with human and animal poisonings. Due to its toxicity in combination with its widespread occurrence, the development of reliable methods for selective, sensitive detection and accurate quantification is mandatory. Liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis using stable isotope dilution analysis (SIDA) represents an ideal tool for this purpose. U-[(15)N5]-CYN was synthesized by culturing Aphanizomenon flos-aquae in Na(15)NO3-containing cyanobacteria growth medium followed by a cleanup using graphitized carbon black columns and mass spectrometric characterization. Subsequently, a SIDA-LC-MS/MS method for the quantification of CYN in freshwater and Brassica matrices was developed showing satisfactory performance data. The recovery ranged between 98 and 103 %; the limit of quantification was 15 ng/L in freshwater and 50 μg/kg dry weight in Brassica samples. The novel SIDA was applied for CYN determination in real freshwater samples as well as in kale and in vegetable mustard exposed to toxin-containing irrigation water. Two of the freshwater samples taken from German lakes were found to be CYN-contaminated above limit of quantification (17.9 and 60.8 ng/L). CYN is systemically available to the examined vegetable species after exposure of the rootstock leading to CYN mass fractions in kale and vegetable mustard leaves of 15.0 μg/kg fresh weight and 23.9 μg/kg fresh weight, respectively. CYN measurements in both matrices are exemplary for the versatile applicability of the developed method in environmental analysis.

  3. Phoenix v. 1.0-SNAPSHOT

    SciTech Connect

    Bastian, Mark; Trigueros, Jose V.

    2016-09-21

    Phoenix is a Java Virtual Machine (JVM) based library for performing mathematical and astrodynamics calculations. It consists of two primary sub-modules, phoenix-math and phoenix-astrodynamics. The mathematics package has a variety of mathematical classes for performing 3D transformations, geometric reasoning, and numerical analysis. The astrodynamics package has various classes and methods for computing locations, attitudes, accesses, and other values useful for general satellite modeling and simulation. Methods for computing celestial locations, such as the location of the Sun and Moon, are also included. Phoenix is meant to be used as a library within the context of a larger application. For example, it could be used for a web service, desktop client, or to compute simple values in a scripting environment.

  4. Video-rate chemical identification and visualization with snapshot hyperspectral imaging

    NASA Astrophysics Data System (ADS)

    Bodkin, Andrew; Sheinis, A.; Norton, A.; Daly, J.; Roberts, C.; Beaven, S.; Weinheimer, J.

    2012-06-01

    Hyperspectral imaging has important benefits in remote sensing and target discrimination applications. This paper describes a class of snapshot-mode hyperspectral imaging systems which utilize a unique optical processor that provides video-rate hyperspectral datacubes. This system consists of numerous parallel optical paths which collect the full threedimensional (two spatial, one spectral) hyperspectral datacube with each video frame and are ideal for recording data from transient events, or on unstable platforms. We will present the results of laboratory and field-tests for several of these imagers operating at visible, near-infrared, MWIR and LWIR wavelengths. Measurement results for nitrate detection and identification as well as additional chemical identification and analysis will be presented.

  5. Requirements for future automotive batteries - a snapshot

    NASA Astrophysics Data System (ADS)

    Karden, Eckhard; Shinn, Paul; Bostock, Paul; Cunningham, James; Schoultz, Evan; Kok, Daniel

    Introduction of new fuel economy, performance, safety, and comfort features in future automobiles will bring up many new, power-hungry electrical systems. As a consequence, demands on automotive batteries will grow substantially, e.g. regarding reliability, energy throughput (shallow-cycle life), charge acceptance, and high-rate partial state-of-charge (HRPSOC) operation. As higher voltage levels are mostly not an economically feasible alternative for the short term, the existing 14 V electrical system will have to fulfil these new demands, utilizing advanced 12 V energy storage devices. The well-established lead-acid battery technology is expected to keep playing a key role in this application. Compared to traditional starting-lighting-ignition (SLI) batteries, significant technological progress has been achieved or can be expected, which improve both performance and service life. System integration of the storage device into the vehicle will become increasingly important. Battery monitoring systems (BMS) are expected to become a commodity, penetrating the automotive volume market from both highly equipped premium cars and dedicated fuel-economy vehicles (e.g. stop/start). Battery monitoring systems will allow for more aggressive battery operating strategies, at the same time improving the reliability of the power supply system. Where a single lead-acid battery cannot fulfil the increasing demands, dual-storage systems may form a cost-efficient extension. They consist either of two lead-acid batteries or of a lead-acid battery plus another storage device.

  6. In situ iron isotope ratio determination using UV-femtosecond laser ablation with application to hydrothermal ore formation processes

    NASA Astrophysics Data System (ADS)

    Horn, Ingo; von Blanckenburg, Friedhelm; Schoenberg, Ronny; Steinhoefel, Grit; Markl, Gregor

    2006-07-01

    The feasibility of in situ stable Fe isotope ratio measurements using UV-femtosecond laser ablation connected to a multiple-collector inductively coupled plasma mass spectrometer (MC-ICP-MS) has been investigated. Different types of matrices, independently determined by solution MC-ICP-MS after chromatographic separation of Fe, have been analysed by laser ablation using the isotopically certified iron reference material IRMM-014 as the bracketing standard. The samples have been pure iron metal (JM Puratronic), Fe-meteorites (North Chile, Glenormiston and Toluca), the meteorite phases kamacite and taenite in Toluca and Fe-sulphides. Furthermore, Fe isotope ratios from hydrothermal hematite, siderite and goethite from an old mining area in the Schwarzwald, Germany, and of magnetite from the metamorphic Biwabik iron formation have been determined. The results show that a precision of better than 0.1‰ (2 sigma) can be achieved with laser ablation and that all the results obtained agree with those determined by solution ICP to better than 0.1‰. This precision and accuracy is achievable in both raster and spot ablation mode. A matrix-matched bracketing standard is not required , and all these materials can be measured accurately against a metal standard. The hydrothermal minerals show significant Fe isotope zonations. In some samples the range of δ56Fe in a single aggregate encompasses the entire spectrum of ratios found by bulk solution analyses in multiple samples distributed over the whole mining district. For example, isotopic zonations found in secondary fibrous hematites show a continuous change in the δ56Fe values from -0.5‰ in the core to -1.8‰ in the rim. Primary hydrothermal siderite shows the reverse pattern with lighter values in the core than in the rim. While the siderite is thought to record primary fluid histories, the hematite pattern is interpreted as a reworked isotopic signature generated by oxic dissolution of primary zoned siderite and

  7. Optimization and application of ICPMS with dynamic reaction cell for precise determination of 44Ca/40Ca isotope ratios.

    PubMed

    Boulyga, Sergei F; Klötzli, Urs; Stingeder, Gerhard; Prohaska, Thomas

    2007-10-15

    An inductively coupled plasma mass spectrometer with dynamic reaction cell (ICP-DRC-MS) was optimized for determining (44)Ca/(40)Ca isotope ratios in aqueous solutions with respect to (i) repeatability, (ii) robustness, and (iii) stability. Ammonia as reaction gas allowed both the removal of (40)Ar+ interference on (40)Ca+ and collisional damping of ion density fluctuations of an ion beam extracted from an ICP. The effect of laboratory conditions as well as ICP-DRC-MS parameters such a nebulizer gas flow rate, rf power, lens potential, dwell time, or DRC parameters on precision and mass bias was studied. Precision (calculated using the "unbiased" or "n - 1" method) of a single isotope ratio measurement of a 60 ng g(-1) calcium solution (analysis time of 6 min) is routinely achievable in the range of 0.03-0.05%, which corresponded to the standard error of the mean value (n = 6) of 0.012-0.020%. These experimentally observed RSDs were close to theoretical precision values given by counting statistics. Accuracy of measured isotope ratios was assessed by comparative measurements of the same samples by ICP-DRC-MS and thermal ionization mass spectrometry (TIMS) by using isotope dilution with a (43)Ca-(48)Ca double spike. The analysis time in both cases was 1 h per analysis (10 blocks, each 6 min). The delta(44)Ca values measured by TIMS and ICP-DRC-MS with double-spike calibration in two samples (Ca ICP standard solution and digested NIST 1486 bone meal) coincided within the obtained precision. Although the applied isotope dilution with (43)Ca-(48)Ca double-spike compensates for time-dependent deviations of mass bias and allows achieving accurate results, this approach makes it necessary to measure an additional isotope pair, reducing the overall analysis time per isotope or increasing the total analysis time. Further development of external calibration by using a bracketing method would allow a wider use of ICP-DRC-MS for routine calcium isotopic measurements, but it

  8. Application of Inductively Coupled Plasma Mass Spectrometry to the determination of uranium isotope ratios in individual particles for nuclear safeguards

    NASA Astrophysics Data System (ADS)

    Zhang, Xiao Zhi; Esaka, Fumitaka; Esaka, Konomi T.; Magara, Masaaki; Sakurai, Satoshi; Usuda, Shigekazu; Watanabe, Kazuo

    2007-10-01

    The capability of inductively coupled plasma mass spectrometry (ICP-MS) for the determination of uranium isotope ratios in individual particles was determined. For this purpose, we developed an experimental procedure including single particle transfer with a manipulator, chemical dissolution and isotope ratio analysis, and applied to the analysis of individual uranium particles in certified reference materials (NBL CRM U050 and U350). As the result, the 235U/ 238U isotope ratio for the particle with the diameter between 0.5 and 3.9 μm was successfully determined with the deviation from the certified ratio within 1.8%. The relative standard deviation (R.S.D.) of the 235U/ 238U isotope ratio was within 4.2%. Although the analysis of 234U/ 238U and 236U/ 238U isotope ratios gave the results with inferior precision, the R.S.D. within 20% was possible for the measurement of the particle with the diameter more than 2.1 μm. The developed procedure was successfully applied to the analysis of a simulated environmental sample prepared from a mixture of indoor dust (NIST SRM 2583) and uranium particles (NBL CRM U050, U350 and U950a). From the results, the proposed procedure was found to be an alternative analytical tool for nuclear safeguards.

  9. Analyzing Nuclear Fuel Cycles from Isotopic Ratios of Waste Products Applicable to Measurement by Accelerator Mass Spectrometry

    SciTech Connect

    Biegalski, S R; Whitney, S M; Buchholz, B

    2005-08-24

    An extensive study was conducted to determine isotopic ratios of nuclides in spent fuel that may be utilized to reveal historical characteristics of a nuclear reactor cycle. This forensic information is important to determine the origin of unknown nuclear waste. The distribution of isotopes in waste products provides information about a nuclear fuel cycle, even when the isotopes of uranium and plutonium are removed through chemical processing. Several different reactor cycles of the PWR, BWR, CANDU, and LMFBR were simulated for this work with the ORIGEN-ARP and ORIGEN 2.2 codes. The spent fuel nuclide concentrations of these reactors were analyzed to find the most informative isotopic ratios indicative of irradiation cycle length and reactor design. Special focus was given to long-lived and stable fission products that would be present many years after their creation. For such nuclides, mass spectrometry analysis methods often have better detection limits than classic gamma-ray spectroscopy. The isotopic ratios {sup 151}Sm/{sup 146}Sm, {sup 149}Sm/{sup 146}Sm, and {sup 244}Cm/{sup 246}Cm were found to be good indicators of fuel cycle length and are well suited for analysis by accelerator mass spectroscopy.

  10. Application of stable isotope analyses as support for determination of hydrological response of nonhomogeneous catchment of the Ljubljanica River

    NASA Astrophysics Data System (ADS)

    Sapač, Klaudija; Bezak, Nejc; Lojen, Sonja; Petrič, Metka; Gabrovšek, Franci; Rusjan, Simon

    2017-04-01

    Since all of the questions in hydrology cannot be answered with hydrological measurements, hydrologists have been applying stable isotopes analyses for several decades in their research. For example, with stable isotopes flow paths of rainfall to the streams can be identified and mean residence time can be estimated. Only with traditional measurements and conventional hydrological analyses on small catchments, which have relatively homogenous properties, it is difficult (and doubtful) to make conclusions about spatial extrapolation of rainfall runoff in a larger non-homogeneous catchment. In the scope of the research project Modelling of Hydrologic Response of Nonhomogeneous Catchments stable isotopes (18O, 2H) will be used for the determination of the hydrological control mechanisms, which regulate rainfall runoff in individual hydrologically homogeneous sub-areas (e.g. karst area). Based on the measurements, we will try to improve the existing hydrological models and introduce new approaches especially in terms of the possibilities for the calibration of hydrological models. Isotope measurements will be supported by traditional hydrological measurements of precipitation, discharge, sediment transport and water chemistry. Combination of isotopic measurements and traditional measurements at relatively large catchment of the Ljubljanica River (approx. 1,990 km2), which has a nonhomogeneous composition (karst hinterland and torrential tributary Gradaščica River), will represent a new approach to hydrological analyses both in Slovenia and worldwide.

  11. Carbon, nitrogen and sulphur isotopic fractionation in captive juvenile hooded seal (Cystophora cristata): Application for diet analysis.

    PubMed

    Pinzone, Marianna; Acquarone, Mario; Huyghebaert, Loreen; Sturaro, Nicolas; Michel, Loïc N; Siebert, Ursula; Das, Krishna

    2017-10-30

    Intrinsic biogeochemical markers, such as stable isotope ratios of carbon, nitrogen and sulphur, are increasingly used to trace the trophic ecology of marine top predators. However, insufficient knowledge of fractionation processes in tissues continues to hamper the use of these markers. We performed a controlled feeding experiment with eight juvenile hooded seals (Cystophora cristata) that were held on a herring-based diet (Clupea harengus) for two years. Stable isotope ratios were measured via isotope ratio mass spectrometry in three of their tissues and related to values of these markers in their diet. Diet-tissue isotope enrichment (trophic enrichment factor, TEF) values between dietary herring and seal tissues for carbon (Δ(13) C) were +0.7 ‰ for red blood cells, +1.9 ‰ for hair and +1.1 ‰ for muscle. The TEFs for nitrogen trophic (Δ(15) N) were +3.3 ‰ for red blood cells, +3.6 ‰ for hair and +4.3 ‰ for muscle. For sulphur, the Δ(34) S values were +1.1 ‰ for red blood cells, +1.0 ‰ for hair and +0.9 ‰ for muscle. These enrichment values were greater than those previously measured in adult seals. This increase may be related to the higher rate of protein synthesis and catabolism in growing animals. This study is the first report on sulphur isotope enrichment values for a marine mammal species. Copyright © 2017 John Wiley & Sons, Ltd.

  12. Computer Generated Snapshot of Our Sun's Magnetic Field

    NASA Technical Reports Server (NTRS)

    2003-01-01

    These banana-shaped loops are part of a computer-generated snapshot of our sun's magnetic field. The solar magnetic-field lines loop through the sun's corona, break through the sun's surface, and cornect regions of magnetic activity, such as sunspots. This image --part of a magnetic-field study of the sun by NASA's Allen Gary -- shows the outer portion (skins) of interconnecting systems of hot (2 million degrees Kelvin) coronal loops within and between two active magnetic regions on opposite sides of the sun's equator. The diameter of these coronal loops at their foot points is approximately the same size as the Earth's radius (about 6,000 kilometers).

  13. Parallel image registration method for snapshot Fourier transform imaging spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhang, Yu; Zhu, Shuaishuai; Lin, Jie; Zhu, Feijia; Jin, Peng

    2017-08-01

    A fast and precise registration method for multi-image snapshot Fourier transform imaging spectroscopy is proposed. This method accomplishes registration of an image array using the positional relationship between homologous points in the subimages, which are obtained offline by preregistration. Through the preregistration process, the registration problem is converted to the problem of using a registration matrix to interpolate subimages. Therefore, the hardware interpolation of graphics processing unit (GPU) texture memory, which has speed advantages for its parallel computing, can be used to significantly enhance computational efficiency. Compared to a central processing unit, GPU performance showed ˜27 times acceleration in registration efficiency.

  14. Source apportionment of methane using a triple isotope approach - Method development and application in the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Steinbach, Julia; Holmstrand, Henry; Semiletov, Igor; Shakhova, Natalia; Shcherbakova, Kseniia; Kosmach, Denis; Sapart, Célia J.; Gustafsson, Örjan

    2015-04-01

    We present a method for measurements of the stable and radiocarbon isotope systems of methane in seawater and sediments. The triple isotope characterization of methane is useful in distinguishing different sources and for improving our understanding of biogeochemical processes affecting methane in the water column. D14C-CH4 is an especially powerful addition to stable isotope analyses in distinguishing between thermogenic and biogenic origins of the methane. Such measurements require large sample sizes, due to low natural abundance of the radiocarbon in CH4. Our system for sample collection, methane extraction and purification builds on the approach by Kessler and Reeburgh (Limn. & Ocean. Meth., 2005). An in-field system extracts methane from 30 -120 l water or 1-2 l sediment (depending on the in-situ methane concentration) by purging the samples with Helium to transfer the dissolved methane to the headspace and circulating it through cryogenically cooled absorbent traps where methane is collected. The in-field preparation eliminates the risks of storage and transport of large seawater quantities and subsequent leakage of sample gas as well as ongoing microbial processes and chemical reactions that may alter the sample composition. In the subsequent shore-based treatment, a laboratory system is used to purify and combust the collected CH4 to AMS-amenable CO2. Subsamples from the methane traps are analyzed for stable isotopes and compared to stable isotope measurements directly measured from small water samples taken in parallel, to correct for any potential fractionation occurring during this process. The system has been successfully tested and used on several shorter shipboard expeditions in the Baltic Sea and on a long summer expedition across the Arctic Ocean. Here we present the details of the method and testing, as well as first triple isotope field data from two cruises to the Landsort Deep area in the Central Baltic Sea.

  15. An Improved Method for TIMS High Precision Nd Isotopic Analysis of Very Small Aliquots (1- 10ng) With Example Application in Garnet Sm/Nd Geochronology

    NASA Astrophysics Data System (ADS)

    Baxter, E. F.; Harvey, J.; Mehl, L. Y.; Peterman, E. M.

    2007-12-01

    Technological and scientific developments have demonstrated both the attainability and the utility of very high precision (i.e. 5-20ppm 2 σ) Nd isotopic measurements with TIMS. However such high precision has been limited to relatively large aliquots of Nd, on the order of several hundred nanograms. Several potential applications of precise Nd isotopic measurements, including garnet Sm/Nd geochronology, do not always permit such large samples, instead yielding only a few nanograms of Nd. We have explored and tested an improved method for Nd isotopic analysis of such small (1-10ng) aliquots of Nd using the NdO+ method with a Triton TIMS at Boston University. Analyzing Nd isotopes as the oxide is a well known technique, frequently involving an oxygen bleed valve. Instead, we forego the bleed valve and load samples with a TaO slurry which provides the oxygen source. Using an in-house Nd isotopic standard solution, 4ng loads easily yield stable 2.0-2.5 volt beams resulting in internal precisions of 10ppm 2 σ RSE. Within barrel external precision of 4ng loads of the Nd standard is 13ppm 2 σ RSD (n=20). Long term (6 months, six analysts) external precision of 4ng loads of the standard is currently 23ppm 2 σ RSD (n=55) suggesting that further improvements are possible. As a further test of this method, we dissolved a natural rock sample (a metapelite), separated the Nd using TRU- spec and MLA column chemistry, and loaded nineteen 4ng loads in one barrel. Within barrel external precision was 21ppm 2 σ RSD (n=18). This precision represents a significant advance over previous NdO+ analyses of small samples using an oxygen bleed valve. The TaO loading method for small Nd aliquots is useful in Sm/Nd garnet geochronology as exemplified by two case studies. Garnets from eclogite facies gneisses from Norway ran very well with 2.4-18ng loads and yielded age precision as good as 0.8 million years 2 σ. Conversely, garnets from blueschist facies rocks from Sifnos, Greece, ran

  16. The combined application of organic sulphur and isotope geochemistry to assess multiple sources of palaeobiochemicals with identical carbon skeletons

    NASA Technical Reports Server (NTRS)

    Kohnen, M. E.; Schouten, S.; Sinninghe Damste, J. S.; de Leeuw, J. W.; Merrit, D.; Hayes, J. M.

    1992-01-01

    Five immature sediments from a Messinian evaporitic basin, representing one evaporitic cycle, were studied using molecular organic sulphur and isotope geochemistry. It is shown that a specific carbon skeleton which is present in different "modes of occurrence" ("free" hydrocarbon, alkylthiophene, alkylthiolane, alkyldithiane, alkylthiane, and sulphur-bound in macromolecules) may have different biosynthetic precursors which are possibly derived from different biota. It is demonstrated that the mode of occurrence and the carbon isotopic composition of a sedimentary lipid can be used to "reconstruct" its biochemical precursor. This novel approach of recognition of the suite of palaeobiochemicals present during the time of deposition allows for identification of the biological sources with an unprecedented specificity.

  17. Application of neutral iridium(I) N-heterocyclic carbene complexes in ortho-directed hydrogen isotope exchange.

    PubMed

    Cochrane, Alison R; Irvine, Stephanie; Kerr, William J; Reid, Marc; Andersson, Shalini; Nilsson, Göran N

    2013-01-01

    Bench-stable complexes of the type [Ir(COD)(NHC)Cl] (NHC = N-heterocyclic carbene) have been investigated within the field of hydrogen isotope exchange. By employing a sterically encumbered NHC within such complexes and catalyst loadings of only 5 mol%, moderate to high deuterium incorporations were achieved across a range of aromatic ketones and nitrogen-based heterocycles. The simple and synthetically accessible catalysts reported herein present alternatives to phosphine-based species and increase the available labelling systems with respect to established iridium-based isotope exchange methodologies. Copyright © 2013 John Wiley & Sons, Ltd.

  18. The combined application of organic sulphur and isotope geochemistry to assess multiple sources of palaeobiochemicals with identical carbon skeletons

    NASA Technical Reports Server (NTRS)

    Kohnen, M. E.; Schouten, S.; Sinninghe Damste, J. S.; de Leeuw, J. W.; Merrit, D.; Hayes, J. M.

    1992-01-01

    Five immature sediments from a Messinian evaporitic basin, representing one evaporitic cycle, were studied using molecular organic sulphur and isotope geochemistry. It is shown that a specific carbon skeleton which is present in different "modes of occurrence" ("free" hydrocarbon, alkylthiophene, alkylthiolane, alkyldithiane, alkylthiane, and sulphur-bound in macromolecules) may have different biosynthetic precursors which are possibly derived from different biota. It is demonstrated that the mode of occurrence and the carbon isotopic composition of a sedimentary lipid can be used to "reconstruct" its biochemical precursor. This novel approach of recognition of the suite of palaeobiochemicals present during the time of deposition allows for identification of the biological sources with an unprecedented specificity.

  19. Calcium Isotope Analysis by Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Boulyga, S.; Richter, S.

    2010-12-01

    The variations in the isotopic composition of calcium caused by fractionation in heterogeneous systems and by nuclear reactions can provide insight into numerous biological, geological, and cosmic processes, and therefore isotopic analysis finds a wide spectrum of applications in cosmo- and geochemistry, paleoclimatic, nutritional, and biomedical studies. The measurement of calcium isotopic abundances in natural samples has challenged the analysts for more than three decades. Practically all Ca isotopes suffer from significant isobaric interferences, whereas low-abundant isotopes can be particularly affected by neighboring major isotopes. The extent of natural variations of stable isotopes appears to be relatively limited, and highly precise techniques are required to resolve isotopic effects. Isotope fractionation during sample preparation and measurements and instrumental mass bias can significantly exceed small isotope abundance variations in samples, which have to be investigated. Not surprisingly, a TIMS procedure developed by Russell et al. (Russell et al., 1978. Geochim Cosmochim Acta 42: 1075-1090) for Ca isotope measurements was considered as revolutionary for isotopic measurements in general, and that approach is used nowadays (with small modifications) for practically all isotopic systems and with different mass spectrometric techniques. Nevertheless, despite several decades of calcium research and corresponding development of mass spectrometers, the available precision and accuracy is still not always sufficient to achieve the challenging goals. This presentation discusses figures of merits of presently used analytical methods and instrumentation, and attempts to critically assess their limitations. Additionally, the availability of Ca isotope reference materials will be discussed.

  20. The Role of "Family Snapshots" in Teaching Art History within a Dialogic Pedagogy

    ERIC Educational Resources Information Center

    Baxter, Kristin

    2012-01-01

    Studying images of families in works of art and in snapshots is compelling, and the author wondered if looking at both types of images side by side might help students understand both kinds of images more fully. Snapshots often prompt detailed and vivid stories among family members and friends. Therefore, she wondered if dialogue about snapshots…

  1. Making Science Teaching and Learning Visible through Web-Based "Snapshots of Practice"

    ERIC Educational Resources Information Center

    van Zee, Emily H.; Roberts, Deborah

    2006-01-01

    Documentary websites known as "snapshots of practice" provide vivid examples of teachers' inquiries into issues they have formulated in the context of their own teaching practices and students' learning. Designed with assistance from Carnegie Foundation for the Advancement of Teaching, snapshots of practice can be accessed in the K-12 section of…

  2. Digital Technology Snapshot of the Literacy and Essential Skills Field 2013. Summary Report

    ERIC Educational Resources Information Center

    Trottier, Vicki

    2013-01-01

    From January to March 2013, "Canadian Literacy and Learning Network" (CLLN) conducted a snapshot to provide information about how digital technology tools are being used in the Literacy and Essential Skills (L/ES) field. The snapshot focused primarily on digital tools and activities that meet the organizational needs of provincial and…

  3. The Role of "Family Snapshots" in Teaching Art History within a Dialogic Pedagogy

    ERIC Educational Resources Information Center

    Baxter, Kristin

    2012-01-01

    Studying images of families in works of art and in snapshots is compelling, and the author wondered if looking at both types of images side by side might help students understand both kinds of images more fully. Snapshots often prompt detailed and vivid stories among family members and friends. Therefore, she wondered if dialogue about snapshots…

  4. Occupational Task Profiles: Canadian Literacy and Essential Skills Workforce. A Pan-Canadian Snapshot

    ERIC Educational Resources Information Center

    Harwood, Chris

    2012-01-01

    This "Pan-Canadian Snapshot" explores the competencies needed to work with adults participating in Literacy and/or Essential Skills (L/ES) programs in Canada. The purpose of the "Snapshot" is to: (1) lay a foundation from which to explore the topic of professionalism; (2) identify the types of supports that the L/ES workforce…

  5. Application of 10(13) ohm Faraday cup current amplifiers for boron isotopic analyses by solution mode and laser ablation MC-ICP-MS.

    PubMed

    Lloyd, Nicholas S; Sadekov, Aleksey Yu; Misra, Sambuddha

    2017-10-09

    Boron isotope ratios (δ(11) B values) are used as a proxy for seawater paleo-pH, amongst several other applications. The analytical precision can be limited by the detection of low intensity ion beams from limited sample amounts. High-gain amplifiers offer improvements in signal/noise ratio and can be used to increase measurement precision and reduce sample amounts. 10(13) ohm amplifier technology has previously been applied to several radiogenic systems, but has thus far not been applied to non-traditional stable isotopes. Here we apply 10(13) ohm amplifier technology for the measurement of boron isotope ratios using solution mode MC-ICP-MS and laser ablation mode (LA-) MC-ICP-MS techniques. Precision is shown for reference materials as well as for low-volume foraminifera samples. The baseline uncertainty for a 0.1 pA (10) B ion beam is reduced to < 0.1 ‰ for a typical measurement period. The external precision is better than 0.2 ‰ (2SD) for δ(11) B measurements for solution samples containing as little as 0.8 ng total boron. For in-situ microanalyses with LA-MC-ICP-MS, the external precision of (11) B/(10) B from an in-house calcite standard was 1 ‰ (2SD) for individual spot analyses, and 0.3 ‰ for the mean of ≥ 10 replicate spot analyses. 10(13) ohm amplifier technology is demonstrated to offer advantages for the determination of δ(11) B values by both MC-ICP-MS and LA-MC-ICP-MS for small samples of biogenic carbonates, such as foraminifera shells. 10(13) ohm amplifier technology will also be of benefit to other non-traditional stable isotope measurements. This article is protected by copyright. All rights reserved.

  6. A snapshot attractor view of the advection of inertial particles in the presence of history force

    NASA Astrophysics Data System (ADS)

    Guseva, Ksenia; Daitche, Anton; Tél, Tamás

    2017-06-01

    We analyse the effect of the Basset history force on the sedimentation or rising of inertial particles in a two-dimensional convection flow. We find that the concept of snapshot attractors is useful to understand the extraordinary slow convergence due to long-term memory: an ensemble of particles converges exponentially fast towards a snapshot attractor, and this attractor undergoes a slow drift for long times. We demonstrate for the case of a periodic attractor that the drift of the snapshot attractor can be well characterized both in the space of the fluid and in the velocity space. For the case of quasiperiodic and chaotic dynamics we propose the use of the average settling velocity of the ensemble as a distinctive measure to characterize the snapshot attractor and the time scale separation corresponding to the convergence towards the snapshot attractor and its own slow dynamics.

  7. Transuranium isotopes

    SciTech Connect

    Hoffman, D.C.

    1985-12-01

    The needs of the research community for the production of transuranium isotopes, the quantities required, the continuity of production desired, and what a new steady state neutron source would have to provide to satisfy these needs are discussed. Examples of past frontier research which need these isotopes as well as an outline of the proposed Large Einsteinium Activation Program, LEAP, which requires roughly ten times the current production of /sup 254/Es are given. 15 refs., 5 figs., 4 tabs.

  8. Isotopic Paleoclimatology

    NASA Astrophysics Data System (ADS)

    Bowen, R.

    Paleotemperature scales were calculated by H. C. Urey and others in the 1950s to assess past temperatures, and later work using the stable isotopes of oxygen, hydrogen, and carbon employed standards such as Peedee belemnite (PDB) and Standard Mean Ocean Water (SMOW). Subsequently, subjects as diverse as ice volume and paleotemperatures, oceanic ice and sediment cores, Pleistocene/Holocene climatic changes, and isotope chronostratigraphy extending back to the Precambrian were investigated.

  9. Provenancing of unidentified World War II casualties: Application of strontium and oxygen isotope analysis in tooth enamel.

    PubMed

    Font, Laura; Jonker, Geert; van Aalderen, Patric A; Schiltmans, Els F; Davies, Gareth R

    2015-01-01

    In 2010 and 2012 two sets of unidentified human remains of two World War II soldiers were recovered in the area where the 1944-1945 Kapelsche Veer bridgehead battle took place in The Netherlands. Soldiers of four Allied nations: British Royal Marine Commandos, Free Norwegian Commandos, Free Poles and Canadians, fought against the German Army in this battle. The identification of these two casualties could not be achieved using dental record information of DNA analysis. The dental records of Missing in Action soldiers of the Allied nations did not match with the dental records of the two casualties. A DNA profile was determined for the casualty found in 2010, but no match was found. Due to the lack of information on the identification of the casualties provided by routine methods, an isotope study was conducted in teeth from the soldiers to constrain their provenance. The isotope study concluded that the tooth enamel isotope composition for both casualties matched with an origin from the United Kingdom. For one of the casualties a probable origin from the United Kingdom was confirmed, after the isotope study was conducted, by the recognition of a characteristic belt buckle derived from a Royal Marine money belt, only issued to British Royal Marines, found with the remains of the soldier. Copyright © 2014 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.

  10. Distribution coefficients of 60 elements on TODGA resin: application to Ca, Lu, Hf, U and Th isotope geochemistry.

    PubMed

    Pourmand, Ali; Dauphas, Nicolas

    2010-05-15

    Batch equilibration experiments are conducted to measure the distribution coefficients (K(d)) of a large number of elements in nitric, nitric plus hydrofluoric, and hydrochloric acids on Eichrom TODGA extraction chromatography resin. The K(d)s are used to devise a multi-element extraction scheme for high-precision elemental and isotopic analyses of Ca, Hf, Lu, Th and U in geological materials, using high-purity lithium metaborate (LiBO(2)) flux fusion that allows rapid digestion of even the most refractory materials. The fusion melt, dissolved in nitric acid, is directly loaded to a TODGA cartridge on a vacuum chamber for elemental separation. An Ln-Spec cartridge is used in tandem with TODGA for Lu purification. The entire procedure, from flux digestion to preparation for isotopic analysis, can be completed in a day. The accuracy of the proposed technique is tested by measuring the concentrations of Ca (standard bracketing), Hf, Lu, Th and U (isotope dilution), and the isotopic composition of Hf in geostandards (USNM3529, BCR-2, BHVO-1, AGV-1 and AGV-2). All measurements are in excellent agreement with recommended literature values, demonstrating the effectiveness of the proposed analytical procedure and the versatility of TODGA resin.

  11. Evidence for life in the isotopic analysis of surface sulphates in the Haughton impact structure, and potential application on Mars

    NASA Astrophysics Data System (ADS)

    Parnell, John; Boyce, Adrian J.; Osinski, Gordon R.; Izawa, Matthew R. M.; Banerjee, Neil; Flemming, Roberta; Lee, Pascal

    2012-04-01

    The analysis of sulphur isotopic compositions in three sets of surface sulphate samples from the soil zone in the Haughton impact structure shows that they are distinct. They include surface gypsum crusts remobilized from the pre-impact gypsum bedrock (mean δ34S +31‰), efflorescent copiapite and fibroferrite associated with hydrothermal marcasite (mean δ34S -37‰), and gypsum-iron oxide crusts representing weathering of pyritic crater-fill sediments (mean δ34S +7‰). Their different compositions reflect different histories of sulphur cycling. Two of the three sulphates have isotopically light (low δ34S) compositions compared with the gypsum bedrock (mean δ34S +31‰), reflecting derivation by weathering of sulphides (three sets of pyrite/marcasite samples with mean δ34S of -41, -20 and -8‰), which had in turn been precipitated by microbial sulphate reduction. Thus, even in the absence of the parent sulphides due to surface oxidation, evidence of life would be preserved. This indicates that on Mars, where surface oxidation may rule out sampling of sulphides during robotic exploration, but where sulphates are widespread, sulphur isotope analysis is a valuable tool that could be sensitive to any near-surface microbial activity. Other causes of sulphur isotopic fractionation on the surface of Mars are feasible, but any anomalous fractionation would indicate the desirability of further analysis.

  12. Applications of Inductively Coupled Plasma Mass Spectroscopy to the Isotopically Enriched Tungsten Metal Ring Campaign at DIII-D

    NASA Astrophysics Data System (ADS)

    Donovan, D. C.; Eley, C.; Maan, A.; Duran, J.; Auxier, J., II; Unterberg, E. A.; Rudakov, D. L.; Stangeby, P.; Chrobak, C.; Wampler, W. R.

    2016-10-01

    Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) was used to measure isotopic ratios of deposited W on collector probes inserted during the metal ring campaign. Two toroidal rings of 5 cm wide W-coated TZM inserts were installed in the lower divertor. The inner ring was coated in natural-W and the outer ring was coated with 93% isotopically enriched W-182. A triplet set of replaceable graphite collector probes were mounted at the outboard mid-plane. Over 100 collector probes were exposed. ICP-MS analysis of the collector probes has yielded isotopic ratios of the deposited W, which have been used with the Stable Isotope Mixing Model (SIMM) to estimate the amount of W from each of the divertor rings that contributed to the total W deposition on the probe. Comparisons in strike-point positioning, H-mode/L-mode, and Forward/Reverse Bt are reviewed. Work supported by US DOE under DE-AC05-00OR22725, DE-FG02-07ER54917, DE-FC02-04ER54698, DE-AC04-94AL85000, UT Institute for Nuclear Security.

  13. Application of mercury isotopes for tracing trophic transfer and internal distribution of mercury in marine fish feeding experiments.

    PubMed

    Kwon, Sae Yun; Blum, Joel D; Chirby, Michelle A; Chesney, Edward J

    2013-10-01

    Feeding experiments were performed to investigate mercury (Hg) isotope fractionation during trophic transfer and internal distribution of total Hg (THg) in marine fish on exposure to natural seafood. Young-of-the-year amberjack (Seriola dumerili) were fed with either blackfin tuna (Thunnus atlanticus; 2647 ng/g THg) or brown shrimp (Farfantepenaeus aztecus; 25.1 ng/g THg) for 80 d or 50 d, respectively, and dissected for muscle, liver, kidney, brain, and blood. After 30 d of tuna consumption, Hg isotopes (δ(202) Hg and Δ(199)Hg) of the amberjack organs shifted to the tuna value (δ(202)Hg = 0.55‰, Δ(199)Hg = 1.54‰,), demonstrating the absence of Hg isotope fractionation. When amberjack were fed a shrimp diet, there was an initial mixing of the amberjack organs toward the shrimp value (δ(202)Hg = -0.48‰, Δ(199)Hg = 0.32‰), followed by a cessation of further shifts in Δ(199)Hg and a small shift in δ(202)Hg. The failure of Δ(199)Hg to reach the shrimp value can be attributed to a reduction in Hg bioaccumulation from shrimp resulting from feeding inhibition and the δ(202)Hg shift can be attributed to a small internal fractionation during excretion. Given that the feeding rate and Hg concentration of the diet can influence internal Hg isotope distribution, these parameters must be considered in biosentinel fish studies. © 2013 SETAC.

  14. Snapshot imaging Fraunhofer line discriminator for detection of plant fluorescence

    NASA Astrophysics Data System (ADS)

    Gupta Roy, S.; Kudenov, M. W.

    2015-05-01

    Non-invasive quantification of plant health is traditionally accomplished using reflectance based metrics, such as the normalized difference vegetative index (NDVI). However, measuring plant fluorescence (both active and passive) to determine photochemistry of plants has gained importance. Due to better cost efficiency, lower power requirements, and simpler scanning synchronization, detecting passive fluorescence is preferred over active fluorescence. In this paper, we propose a high speed imaging approach for measuring passive plant fluorescence, within the hydrogen alpha Fraunhofer line at ~656 nm, using a Snapshot Imaging Fraunhofer Line Discriminator (SIFOLD). For the first time, the advantage of snapshot imaging for high throughput Fraunhofer Line Discrimination (FLD) is cultivated by our system, which is based on a multiple-image Fourier transform spectrometer and a spatial heterodyne interferometer (SHI). The SHI is a Sagnac interferometer, which is dispersion compensated using blazed diffraction gratings. We present data and techniques for calibrating the SIFOLD to any particular wavelength. This technique can be applied to quantify plant fluorescence at low cost and reduced complexity of data collection.

  15. A Snapshot Survey of The Most Massive Clusters of Galaxies

    NASA Astrophysics Data System (ADS)

    Ebeling, Harald

    2007-07-01

    We propose the continuation of our highly successful SNAPshot survey of a sample of 125 very X-ray luminous clusters in the redshift range 0.3-0.7. As demonstrated by the 25 snapshots obtained so far in Cycle14 and Cycle15 these systems frequently exhibit strong gravitational lensing as well as spectacular examples of violent galaxy interactions. The proposed observations will provide important constraints on the cluster mass distributions, the physical nature of galaxy-galaxy and galaxy-gas interactions in cluster cores, and a set of optically bright, lensed galaxies for further 8-10m spectroscopy. All of our primary science goals require only the detection and characterisation of high-surface-brightness features and are thus achievable even at the reduced sensitivity of WFPC2. Because of their high redshift and thus compact angular scale our target clusters are less adversely affected by the smaller field of view of WFPC2 than more nearby systems. Acknowledging the broad community interest in this sample we waive our data rights for these observations. Due to a clerical error at STScI our approved Cycle15 SNAP program was barred from execution for 3 months and only 6 observations have been performed to date - reinstating this SNAP at Cycle16 priority is of paramount importance to reach meaningful statistics.

  16. SnapShot: Visualization to Propel Ice Hockey Analytics.

    PubMed

    Pileggi, H; Stolper, C D; Boyle, J M; Stasko, J T

    2012-12-01

    Sports analysts live in a world of dynamic games flattened into tables of numbers, divorced from the rinks, pitches, and courts where they were generated. Currently, these professional analysts use R, Stata, SAS, and other statistical software packages for uncovering insights from game data. Quantitative sports consultants seek a competitive advantage both for their clients and for themselves as analytics becomes increasingly valued by teams, clubs, and squads. In order for the information visualization community to support the members of this blossoming industry, it must recognize where and how visualization can enhance the existing analytical workflow. In this paper, we identify three primary stages of today's sports analyst's routine where visualization can be beneficially integrated: 1) exploring a dataspace; 2) sharing hypotheses with internal colleagues; and 3) communicating findings to stakeholders.Working closely with professional ice hockey analysts, we designed and built SnapShot, a system to integrate visualization into the hockey intelligence gathering process. SnapShot employs a variety of information visualization techniques to display shot data, yet given the importance of a specific hockey statistic, shot length, we introduce a technique, the radial heat map. Through a user study, we received encouraging feedback from several professional analysts, both independent consultants and professional team personnel.

  17. Serial snapshot crystallography for materials science with SwissFEL

    DOE PAGES

    Dejoie, Catherine; Smeets, Stef; Baerlocher, Christian; ...

    2015-04-21

    New opportunities for studying (sub)microcrystalline materials with small unit cells, both organic and inorganic, will open up when the X-ray free electron laser (XFEL) presently being constructed in Switzerland (SwissFEL) comes online in 2017. Our synchrotron-based experiments mimicking the 4%-energy-bandpass mode of the SwissFEL beam show that it will be possible to record a diffraction pattern of up to 10 randomly oriented crystals in a single snapshot, to index the resulting reflections, and to extract their intensities reliably. The crystals are destroyed with each XFEL pulse, but by combining snapshots from several sets of crystals, a complete set of datamore » can be assembled, and crystal structures of materials that are difficult to analyze otherwise will become accessible. Even with a single shot, at least a partial analysis of the crystal structure will be possible, and with 10–50 femtosecond pulses, this offers tantalizing possibilities for time-resolved studies.« less

  18. HydroCrowd: Citizen-empowered snapshot sampling to assess the spatial distribution of stream

    NASA Astrophysics Data System (ADS)

    Kraft, Philipp; Breuer, Lutz; Bach, Martin; Aubert, Alice H.; Frede, Hans-Georg

    2016-04-01

    Large parts of groundwater bodies in Central Europe shows elevated nitrate concentrations. While groundwater samplings characterize the water quality for a longer period, surface water resources, in particular streams, may be subject of fast concentration fluctuations and measurements distributed in time cannot by compared. Thus, sampling should be done in a short time frame (snapshot sampling). To describe the nitrogen status of streams in Germany, we organized a crowdsourcing experiment in the form of a snapshot sampling at a distinct day. We selected a national holiday in fall 2013 (Oct, 3rd) to ensure that a) volunteers have time to take a sample, b) stream water is unlikely to be influenced by recent agricultural fertilizer application, and c) low flow conditions are likely. We distributed 570 cleaned sample flasks to volunteers and got 280 filled flasks back with coordinates and other meta data about the sampled stream. The volunteers were asked to visit any stream outside of settlements and fill the flask with water from that stream. The samples were analyzed in our lab for concentration of nitrate, ammonium and dissolved organic nitrogen (DON), results are presented as a map on the web site http://www.uni-giessen.de/hydrocrowd. The measured results are related to catchment features such as population density, soil properties, and land use derived from national geodata sources. The statistical analyses revealed a significant correlation between nitrate and fraction of arable land (0.46), as well as soil humus content (0.37), but a weak correlation with population density (0.12). DON correlations were weak but significant with humus content (0.14) and arable land (0.13). The mean contribution of DON to total dissolved nitrogen was 22%. Crowdsourcing turned out to be a useful method to assess the spatial distribution of stream solutes, as considerable amounts of samples were collected with comparatively little effort at a single day.

  19. Isotope-labeled aspartate sidechain as a non-perturbing infrared probe: Application to investigate the dynamics of a carboxylate buried inside a protein

    NASA Astrophysics Data System (ADS)

    Abaskharon, Rachel M.; Brown, Stephen P.; Zhang, Wenkai; Chen, Jianxin; Smith, Amos B.; Gai, Feng

    2017-09-01

    Because of their negatively charged carboxylates, aspartate and glutamate are frequently found at the active or binding site of proteins. However, studying a specific carboxylate in proteins that contain multiple aspartates and/or glutamates via infrared spectroscopy is difficult due to spectral overlap. We show, herein, that isotopic-labeling of the aspartate sidechain can overcome this limitation as the resultant 13COO- asymmetric stretching vibration resides in a transparent region of the protein IR spectrum. Applicability of this site-specific vibrational probe is demonstrated by using it to assess the dynamics of an aspartate ion buried inside a small protein via two-dimensional infrared spectroscopy.

  20. Isotopic (18O) characteristics of weekly precipitation collected across the USA: an initial analysis with application to water source studies

    NASA Astrophysics Data System (ADS)

    Welker, J. M.

    2000-06-01

    A portion of the precipitation samples collected and stored by the National Atmospheric Deposition Program (NADP) are shown to be useful for analysis of isotopes in precipitation. The potential problems with evaporation are small based on deuterium excess analyses and comparisons with the Global Meteroic Water Line. Presented here are the 18O values of precipitation collected from nine NADP sites during 1989, 1990 and 1991. The trends in the isotopic (18O) characteristics of recent precipitation are in agreement with findings from previous International Atomic Energy Agency (IAEA) sites in the USA. The findings are also in agreement with several major isotope-environment relationships, further supporting the use of these samples for a modern global data base on the isotopes in precipitation being developed by IAEA, called GNIP (Global Network for Isotopes in Precipitation) and for use by research groups in the hydrological modelling, palaeoclimate and ecological communities.As expected, the average 18O values of precipitation that is derived from the Gulf of Mexico (-3) and from the Pacific North-west are isotopically distinct (-7). In addition, using the NADP network, isotopic depletion in the 18O values of precipitation in the range of 8 was observed from coastal to inland locations either in the Pacific North-west or along the east side of the Rocky Mountains, from Texas to Eastern Montana. In central USA, especially at high elevation, there is a strong seasonal variation in the 18O values of precipitation, differing by almost 25 between January and August, whereas at coastal locations the seasonal variation in the 18O values of precipitation was minimal. Comparisons between the average 18

  1. Relationship Between Clumped Isotope and Growth Temperature of Foraminifera: Methodology and Application to the Mid-Pleistocene Transition

    NASA Astrophysics Data System (ADS)

    Peral, M.; Daëron, M.; Blamart, D.; Bassinot, F. C.; Marino, M.; Nomade, S.; Ciaranfi, N.; Girone, A.; Maiorano, P.; Pereira, A.; Scao, V.

    2016-12-01

    The O-isotope composition (δ18Oc) of marine bio-carbonates alone cannot directly constrain past changes in oceanic temperatures, because δ18Oc also depends on the isotopic composition of seawater, which is often poorly constrained in past environments. The carbonate clumped isotope thermometer, based on the dependence between temperature and statistical over-abundance of 13C-18O bonds in carbonate (Δ47), provides estimates of calcification temperature independent from the isotopic composition of seawater. Past investigation of Δ47 in foraminifera suggests that their clumped isotope composition is consistent with temperature calibration laws obtained from synthetic carbonates [1,2]. Here we report on the early results of our methodological investigations. First, we performed a detailed study, including SEM observations and stable isotope analyses on planktonic foraminifera, aiming to establish optimal cleaning protocols. We subsequently selected three benthic foraminifera in range of 450 to 200μm (sorted in bins of 50μm) to test size and/or species effect. Our "optimal" protocols were then applied to test the relationship between ∆47 and temperature by comparison with synthetic carbonates believed to have formed close to thermodynamic equilibrium. The isotopic values of ∆47 are compared to marine temperature from Mg/Ca and from NOAA database. Modern annual temperatures range from 7 to 25°C between our sites. The results obtained using the temperature from NOAA database are statistically indistinguishable from those derived from the local (LSCE) carbonate calibration law. Finally, we apply this relationship to six benthic foraminifer samples coming from the continental (paleo-marine) section Montalbano Jonico (Italy), corresponding respectively to MIS 34, MIS 31, MIS 22-21, and MIS 20-19, in order to constrain paleo-temperatures for these glacial-interglacial couples and to estimate local seawater temperatures and δ18O during the Mid

  2. Stable isotope compositions of Unionidae shells from Lake Balaton (Hungary): Behaviour of recent shells and archaeological applications

    NASA Astrophysics Data System (ADS)

    Scholl-Barna, Gabriella; Demeny, Attila; Sumegi, Pal; Serlegi, Gabor; Fabian, Szilvia; Cserny, Tibor; Forizs, Istvan; Bajnoczi, Bernadett

    2010-05-01

    Stable oxygen and carbon isotope compositions of bivalve carbonate (Unio sp.) were measured in order to understand how climate conditions are reflected by the isotopic compositions of shell material from Lake Balaton (Hungary). Samples were taken also from Anodonta and Dreissena species from the same period and were also analysed to study interspecies variation. Monitoring of physical parameters and oxygen isotope composition of lake water was conducted between 1999 and 2005 and between 2007 and 2009 and the data were compared with the stable isotopic compositions of Unio shell specimens grown in the same period. Sampling conducted at high resolution revealed variations related to seasonal fluctuations. The period studied contain wet and extremely dry periods beyond the normal years that made the studied period appropriate to determine if the shells can be used for climate studies. As we have seen, the Unio shells systematically and reliably reflect temperature and isotopic variations, so these shells can potentially be used to reconstruct past environmental conditions. Past climate reconstructions based on isotopic variations in shell carbonate have been demonstrated in two archaeological studies on excavation materials of Copper and Bronze Ages. Within the Late Copper Age several subphases have been distinguished that are covered by the excavation sites in Balatonkeresztur (Southern part of Lake Balaton). Settlement migration to higher locations (suggesting a significant rise in lake or groundwater level) and a gradual shift in animal remnants from the dominance of sheep and goat (preferring dryer climate) to swine (suggesting a wetter climate) have been observed between the Boleraz (5460-5310 calBP) and Early Classical Baden (5310-5060 cal BP) subphases. Based on geomorphological and archaeozoological studies, a dry to wet climate change can be suggested which have been detected by palynological analyses as well. Based on stable isotopic compositions of shell

  3. New Isotopic Tracers for Shale Gas and Hydraulic Fracturing Fluids

    EPA Pesticide Factsheets

    The combined application of geochemistry, stable isotopes (δ18O, δ2H), strontium isotopes (87Sr/86Sr), boron isotopes (δ11B), and radium isotopes (228Ra/226Ra) provides a unique methodology for tracing and monitoring shale gas and fracking fluids in the environment.

  4. Re-evaluation of the hydrogen stable isotopic composition of keratin calibration standards for wildlife and forensic science applications.

    PubMed

    Soto, David X; Koehler, Geoff; Wassenaar, Leonard I; Hobson, Keith A

    2017-07-30

    Determination of non-exchangeable hydrogen isotopic compositions (δ(2) H values) of bulk complex organic materials is difficult due to uncontrolled H isotope exchange between the organic material and ambient water vapor. A number of calibration keratinous materials with carefully measured hydrogen isotopic compositions of the non-exchangeable fraction were proposed to enable stable isotope laboratories to normalize their (2) H measurements. However, it was recently reported that high-temperature carbon-reactor methods for measuring the hydrogen isotopic composition of nitrogenous organic materials is biased by the production of HCN in the reactor. As a result, the reported values of these calibration materials needed to be re-evaluated. We evaluated the non-exchangeable δ(2) HVSMOW values of keratins EC1 (CBS) and EC2 (KHS), USGS hair standards, and a range of other nitrogenous widely used organic laboratory calibration materials (collagen and chitin) using pre-treatment with a preparation device designed to eliminate residual moisture and quantify exchangeable H. The revised non-exchangeable δ(2) HVSMOW values of EC-1 (CBS) and EC-2 (KHS) keratin standard materials were -157.0 ± 0.9 and -35.3 ± 1.1 ‰, respectively. The revised values of USGS42 and USGS43 were -72.2 ± 0.9 and -44.2 ± 1.0 ‰, respectively, in excellent agreement with previous results. For routine H isotope analyses, with proper sample pre-treatment, we show that the Comparative Equilibration approach can provide accurate and reproducible non-exchangeable δ(2) H values among laboratories regardless of the reactor type used. © 2017 Her Majesty the Queen in Right of Canada Rapid Communications in Mass Spectrometry © 2017 John Wiley & Sons Ltd. Reproduced with the permission of the Environment and Climate Change Canada. © 2017 Her Majesty the Queen in Right of Canada Rapid Communications in Mass Spectrometry © 2017 John Wiley & Sons Ltd. Reproduced with the permission of the

  5. Isotope separation by laser means

    DOEpatents

    Robinson, C. Paul; Jensen, Reed J.; Cotter, Theodore P.; Greiner, Norman R.; Boyer, Keith

    1982-06-15

    A process for separating isotopes by selective excitation of isotopic species of a volatile compound by tuned laser light. A highly cooled gas of the volatile compound is produced in which the isotopic shift is sharpened and defined. Before substantial condensation occurs, the cooled gas is irradiated with laser light precisely tuned to a desired wavelength to selectively excite a particular isotopic species in the cooled gas. The laser light may impart sufficient energy to the excited species to cause it to undergo photochemical reaction or even to photoionize. Alternatively, a two-photon irradiation may be applied to the cooled gas to induce photochemical reaction or photoionization. The process is particularly applicable to the separation of isotopes of uranium and plutonium.

  6. Application of carbon and hydrogen stable isotope analyses to detect exogenous citric acid in Japanese apricot liqueur.

    PubMed

    Akamatsu, Fumikazu; Oe, Takaaki; Hashiguchi, Tomokazu; Hisatsune, Yuri; Kawao, Takafumi; Fujii, Tsutomu

    2017-08-01

    Japanese apricot liqueur manufacturers are required to control the quality and authenticity of their liqueur products. Citric acid made from corn is the main acidulant used in commercial liqueurs. In this study, we conducted spiking experiments and carbon and hydrogen stable isotope analyses to detect exogenous citric acid used as an acidulant in Japanese apricot liqueurs. Our results showed that the δ(13)C values detected exogenous citric acid originating from C4 plants but not from C3 plants. The δ(2)H values of citric acid decreased as the amount of citric acid added increased, whether the citric acid originated from C3 or C4 plants. Commercial liqueurs with declared added acidulant provided higher δ(13)C values and lower δ(2)H values than did authentic liqueurs and commercial liqueurs with no declared added acidulant. Carbon and hydrogen stable isotope analyses are suitable as routine methods for detecting exogenous citric acid in Japanese apricot liqueur.

  7. Terpane biomarkers and carbon isotopes in environmental geochemistry-application of a case study from Prince William Sound, Alaska

    SciTech Connect

    Kvenvolden, K.A.; Hostettler, F.D.; Rosenbauer, R.J.; Hostetter, D.E.; Castle, W.T.

    1996-12-31

    Geochemical studies in Prince William Sound, Alaska, following the 1989 Exxon Valdez oil spill have provided information that is being used to interpret preliminary environmental geochemical observations made in coastal California. Although the shorelines of Prince William Sound still retain traces of the 1989 oil spill, most of the flattened tar balls that can be found today on these shorelines are not residues of Exxon Valdez oil. Rather, the hydrocarbon-biomarker and carbon-isotopic signatures of these tar balls have remarkably similar characteristics that are consistent with those of oil products that originated from Monterey Formation source rocks of California. Some of these products were spilled into the sound during the 1964 Alaskan earthquake. Selected terpane biomarker ratios and carbon isotope composition of whole oil samples can geochemically distinguish Exxon Valdez residues from the tar balls. Results are discussed.

  8. Oxygen isotope fractionation between bird eggshell calcite and body water: application to fossil eggs from Lanzarote (Canary Islands).

    PubMed

    Lazzerini, Nicolas; Lécuyer, Christophe; Amiot, Romain; Angst, Delphine; Buffetaut, Eric; Fourel, François; Daux, Valérie; Betancort, Juan Francisco; Flandrois, Jean-Pierre; Marco, Antonio Sánchez; Lomoschitz, Alejandro

    2016-10-01

    Oxygen and carbon isotope compositions of fossil bird eggshell calcite (δ(18)Ocalc and δ(13)Ccalc) are regularly used to reconstruct paleoenvironmental conditions. However, the interpretation of δ(18)Ocalc values of fossil eggshells has been limited to qualitative variations in local climatic conditions as oxygen isotope fractionations between calcite, body fluids, and drinking water have not been determined yet. For this purpose, eggshell, albumen water, and drinking water of extant birds have been analyzed for their oxygen and carbon isotope compositions. Relative enrichments in (18)O relative to (16)O between body fluids and drinking water of +1.6 ± 0.9 ‰ for semi-aquatic birds and of +4.4 ± 1.9 ‰ for terrestrial birds are observed. Surprisingly, no significant dependence to body temperature on the oxygen isotope fractionation between eggshell calcite and body fluids is observed, suggesting that bird eggshells precipitate out of equilibrium. Two empirical equations relating the δ(18)Ocalc value of eggshell calcite to the δ(18)Ow value of ingested water have been established for terrestrial and semi-aquatic birds. These equations have been applied to fossil eggshells from Lanzarote in order to infer the ecologies of the Pleistocene marine bird Puffinus sp. and of the enigmatic giant birds from the Pliocene. Both δ(13)Ccalc and δ(18)Ocalc values of Puffinus eggshells point to a semi-aquatic marine bird ingesting mostly seawater, whereas low δ(13)Ccalc and high δ(18)Ocalc values of eggshells from the Pliocene giant bird suggest a terrestrial lifestyle. This set of equations can help to quantitatively estimate the origin of waters ingested by extinct birds as well as to infer either local environmental or climatic conditions.

  9. Oxygen isotope fractionation between bird eggshell calcite and body water: application to fossil eggs from Lanzarote (Canary Islands)

    NASA Astrophysics Data System (ADS)

    Lazzerini, Nicolas; Lécuyer, Christophe; Amiot, Romain; Angst, Delphine; Buffetaut, Eric; Fourel, François; Daux, Valérie; Betancort, Juan Francisco; Flandrois, Jean-Pierre; Marco, Antonio Sánchez; Lomoschitz, Alejandro

    2016-10-01

    Oxygen and carbon isotope compositions of fossil bird eggshell calcite (δ18Ocalc and δ13Ccalc) are regularly used to reconstruct paleoenvironmental conditions. However, the interpretation of δ18Ocalc values of fossil eggshells has been limited to qualitative variations in local climatic conditions as oxygen isotope fractionations between calcite, body fluids, and drinking water have not been determined yet. For this purpose, eggshell, albumen water, and drinking water of extant birds have been analyzed for their oxygen and carbon isotope compositions. Relative enrichments in 18O relative to 16O between body fluids and drinking water of +1.6 ± 0.9 ‰ for semi-aquatic birds and of +4.4 ± 1.9 ‰ for terrestrial birds are observed. Surprisingly, no significant dependence to body temperature on the oxygen isotope fractionation between eggshell calcite and body fluids is observed, suggesting that bird eggshells precipitate out of equilibrium. Two empirical equations relating the δ18Ocalc value of eggshell calcite to the δ18Ow value of ingested water have been established for terrestrial and semi-aquatic birds. These equations have been applied to fossil eggshells from Lanzarote in order to infer the ecologies of the Pleistocene marine bird Puffinus sp. and of the enigmatic giant birds from the Pliocene. Both δ13Ccalc and δ18Ocalc values of Puffinus eggshells point to a semi-aquatic marine bird ingesting mostly seawater, whereas low δ13Ccalc and high δ18Ocalc values of eggshells from the Pliocene giant bird suggest a terrestrial lifestyle. This set of equations can help to quantitatively estimate the origin of waters ingested by extinct birds as well as to infer either local environmental or climatic conditions.

  10. Applications of isotope geochemistry to the reconstruction of Yucca Mountain, Nevada, paleohydrology -- Status of investigations: June 1996

    SciTech Connect

    Whelan, J.F.; Moscati, R.J.; Allerton, S.B.M.; Marshall, B.D.

    1998-11-01

    Tunneling of the Exploratory Studies Facility has offered the opportunity to sample and examine occurrences of secondary mineralization found in the unsaturated-zone tuffs of Yucca Mountain, nevada. Petrographic and paragenetic analyses, calcite and silica-phase stable isotopic analyses, and preliminary strontium tracer isotope and radiocarbon age analyses of these samples indicate that (1) an early stage of secondary mineralization consisting largely of chalcedony and quartz, but possibly with or slightly preceded by calcite, probably formed at warmer than ambient temperatures; (2) later secondary mineralization consisting of calcite and opal appears completely consistent with formation from percolation of surface infiltration whose solute load and carbon isotopic compositions reflect passage through the overlying soils; (3) based on textural studies, all unsaturated-zone secondary mineral occurrences exposed within the Exploratory Studies Facility tunnel, with the exception of the vapor-phase assemblages that formed at high temperatures during cooling of the tuffs, probably formed in unsaturated settings; and (4) calcite radiocarbon ages, based on preliminary results, have not been compromised by post-depositional exchange with carbon-bearing water and gases in the unsaturated zone.

  11. Chemical Synthesis of Deoxynivalenol-3-β-d-[(13)C₆]-glucoside and Application in Stable Isotope Dilution Assays.

    PubMed

    Habler, Katharina; Frank, Oliver; Rychlik, Michael

    2016-06-27

    Modified mycotoxins have been gaining importance in recent years and present a certain challenge in LC-MS/MS analysis. Due to the previous lack of a labeled isotopologue of the modified mycotoxin deoxynivalenol-3-glucoside, in our study we synthesized the first (13)C-labeled internal standard. Therefore, we used the Königs-Knorr method to synthesize deoxynivalenol-3-β-d-[(13)C₆]-glucoside originated from unlabeled deoxynivalenol and [(13)C₆]-labeled glucose. Using the synthesized isotopically-labeled standard deoxynivalenol-3-β-d-[(13)C₆]-glucoside and the purchased labeled standard [(13)C15]-deoxynivalenol, a stable isotope dilution LC-MS/MS method was firstly developed for deoxynivalenol-3-glucoside and deoxynivalenol in beer. The preparation and purification of beer samples was based on a solid phase extraction. The validation data of the newly developed method gave satisfying results. Intra- and interday precision studies revealed relative standard deviations below 0.5% and 7%, respectively. The recoveries ranged for both analytes between 97% and 112%. The stable isotope dilution assay was applied to various beer samples from four different countries. In summary, deoxynivalenol-3-glucoside and deoxynivalenol mostly appeared together in varying molar ratios but were quantified in rather low contents in the investigated beers.

  12. Low-complexity image processing for a high-throughput low-latency snapshot multispectral imager with integrated tiled filters

    NASA Astrophysics Data System (ADS)

    Geelen, Bert; Jayapala, Murali; Tack, Nicolaas; Lambrechts, Andy

    2013-05-01

    Traditional spectral imaging cameras typically operate as pushbroom cameras by scanning a scene. This approach makes such cameras well-suited for high spatial and spectral resolution scanning applications, such as remote sensing and machine vision, but ill-suited for 2D scenes with free movement. This limitation can be overcome by single frame, multispectral (here called snapshot) acquisition, where an entire three-dimensional multispectral data cube is sensed at one discrete point in time and multiplexed on a 2D sensor. Our snapshot multispectral imager is based on optical filters monolithically integrated on CMOS image sensors with large layout flexibility. Using this flexibility, the filters are positioned on the sensor in a tiled layout, allowing trade-offs between spatial and spectral resolution. At system-level, the filter layout is complemented by an optical sub-system which duplicates the scene onto each filter tile. This optical sub-system and the tiled filter layout lead to a simple mapping of 3D spectral cube data on the sensor, facilitating simple cube assembly. Therefore, the required image processing consists of simple and highly parallelizable algorithms for reflectance and cube assembly, enabling real-time acquisition of dynamic 2D scenes at low latencies. Moreover, through the use of monolithically integrated optical filters the multispectral imager achieves the qualities of compactness, low cost and high acquisition speed, further differentiating it from other snapshot spectral cameras. Our prototype camera can acquire multispectral image cubes of 256x256 pixels over 32 bands in the spectral range of 600-1000nm at 340 cubes per second for normal illumination levels.

  13. Oxygen Isotopes in Meteorites

    NASA Astrophysics Data System (ADS)

    Clayton, R. N.

    2003-12-01

    al., 1997). The observed oxygen isotopic compositions of presolar corundum grains show clear evidence of nuclear processes in red-giant stars, and have had significant impact on the theory of these stars ( Boothroyd and Sackmann, 1999).There are several possible reasons for the failure to recognize and analyze large populations of oxygen-rich presolar grains:(i) they may not exist: oxygen ejected in supernova explosions may not condense into mineral grains on the short timescale available;(ii) they may be smaller in size than can be detected by applicable techniques (˜0.1 μm); and(iii) they may be destroyed in the laboratory procedures used to isolate other types of presolar grains.

  14. Heavy stable isotopes of oxyanion-forming metals and metalloids (Cr, Se, U, Sb, and Te) as indicators of redox reactions: Theory, systematics, and the outlook for practical applications.

    NASA Astrophysics Data System (ADS)

    Johnson, T. M.

    2016-12-01

    . Accordingly, reduction is the main driver of isotopic variation and is thus likely to be a primary focus of practical applications of Cr, Se, U, Sb, and Te stable isotope measurements.

  15. Comparison of the imaging performances for recently developed monolithic scintillators: CRY018 and CRY019 for dual isotope gamma ray imaging applications

    NASA Astrophysics Data System (ADS)

    Polito, C.; Pani, R.; Trigila, C.; Cinti, M. N.; Fabbri, A.; Frantellizzi, V.; De Vincentis, G.; Pellegrini, R.; Pani, R.

    2017-01-01

    The growing interest for new scintillation crystals with outstanding imaging performances (i.e. resolution and efficiency) has suggested the study of recently discovered scintillators named CRY018 and CRY019. The crystals under investigation are monolithic and have shown enhanced characteristics both for gamma ray spectrometry and for Nuclear Medicine imaging applications such as the dual isotope imaging. Moreover, the non-hygroscopic nature and the absence of afterglow make these scintillators even more attractive for the potential improvement in a wide range of applications. These scintillation crystals show a high energy resolution in the energy range involved in Nuclear Medicine, allowing the discrimination between very close energy values. Moreover, in order to prove their suitability of being powerful imaging systems, the imaging performances like the position linearity and the intrinsic spatial resolution have been evaluated obtaining satisfactory results thanks to the implementation of an optimized algorithm for the images reconstruction.

  16. Snapshots of the Universe: A Multilingual Astronomy Book

    NASA Astrophysics Data System (ADS)

    Beaton, R. L.; Sokal, K. R.; Liss, S. E.; Johnson, K. E.

    2015-11-01

    Dark Skies, Bright Kids! (DSBK) is an outreach organization at the University of Virginia, focused on enhancing elementary level science education in under-served communities. Early in the program, DSBK volunteers encountered difficulties connecting with English as a second language (ESL) students. To meet that challenge, DSBK volunteers created story-book style art with short descriptions of astronomical objects in both Spanish and English to help communicate basic astronomy concepts to these students. Building on this initial success, our simple project has evolved into a full multilingual children's book targeted at 2nd-5th grade students. Though originally in Spanish and English, a partnership with the University of Alberta (Canada) has produced a French translation of the text, broadening the outreach potential of the book. In this contribution, we describe Snapshots of the Universe (Instantáneas del Universo) and reflect upon the process of creating this unique resource.

  17. A snapshot of foundational attitudes toward quantum mechanics

    NASA Astrophysics Data System (ADS)

    Schlosshauer, Maximilian; Kofler, Johannes; Zeilinger, Anton

    2013-08-01

    Foundational investigations in quantum mechanics, both experimental and theoretical, gave birth to the field of quantum information science. Nevertheless, the foundations of quantum mechanics themselves remain hotly debated in the scientific community, and no consensus on essential questions has been reached. Here, we present the results of a poll carried out among 33 participants of a conference on the foundations of quantum mechanics. The participants completed a questionnaire containing 16 multiple-choice questions probing opinions on quantum-foundational issues. Participants included physicists, philosophers, and mathematicians. We describe our findings, identify commonly held views, and determine strong, medium, and weak correlations between the answers. Our study provides a unique snapshot of current views in the field of quantum foundations, as well as an analysis of the relationships between these views.

  18. Design of current mirror integration ROIC for snapshot mode operation

    NASA Astrophysics Data System (ADS)

    Shanker Gupta, Hari; Kiran Kumar, A. S.; Shojaei Baghini, M.; Chakrabarti, Subhananda; Mehta, Sanjeev; Chowdhury, Arup Roy; Sharma, Dinesh K.

    2016-10-01

    Current mirror integration (CMI) read out integrated circuit (ROIC) topology provides a low input impedance to photo-detectors and provides large injection efficiency, large charge handling capacity and snapshot mode operation without in-pixel opamps. The ROIC described in this paper has been implemented with a modified current mirror circuit, with matched PMOS pairs for detector input stage and its biasing. The readout circuit has been designed for 30 × 30 μm2 pixel size, 4 × 4 array size, variable frame rate, 5 Mega pixel per second (Mpps). Experimental performance of the test chip has achieved 15 Me charge handling capacity, a high dynamic range of 83 dB, 99.8% linearity and 99.96% injection efficiency. The ROIC design has been fabricated in 3.3 V 1P6M UMC 180 nm CMOS process and tested up to 5 MHz pixel rate at room and at cryogenic temperature.

  19. What do the pictures say-snapshots of a career.

    PubMed

    Cooper, Terrance G

    2017-06-01

    What follows are snapshots of my career in chicken eyes, yeast and Rhodospirillum rubrum, castor beans, Escherichia coli and finally yeast again. In contrast, only a few of the failures that realistically make up a career are included. It is a tale of the generosity and influences of those who shaped what I am and what I learned in a wonderful profession. The science described is only that which I was lucky enough to do or was performed in my laboratory by those who really deserve the credit for any success that I've enjoyed. Not mentioned for lack of space are the critical contributions of many impressive investigators in the field of nitrogen-responsive regulation for no scientific investigation occurs in isolation. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  20. Implementation of response to intervention: a snapshot of progress.

    PubMed

    Berkeley, Sheri; Bender, William N; Gregg Peaster, Lindsay; Saunders, Lauren

    2009-01-01

    This article provides a snapshot of how all 50 states are progressing with the development and implementation of response-to-intervention (RtI) models 1 year after the final regulations for the Individuals with Disabilities Education Act were passed. Data were collected through a review of existing state department of education Web sites and conversations with representatives in each state department of education. Information related to RtI model type, implementation status, professional development, criteria for eligibility, and specific features of individual state RtI models are presented. Findings indicate that most states are in some phase of RtI development, although approaches vary widely throughout the country. Implications for research and practice are discussed.

  1. Multiscale snapshot imaging spectrometer with large FOV and fast speed

    NASA Astrophysics Data System (ADS)

    Ji, Yiqun; Sasian, Jose; Chen, Yuheng; Zhou, Jiankang

    2014-11-01

    A novel snapshot imaging spectrometer with large field-of-view (FOV) up to 100° is achieved by taking the advantages of a multiscale fore-optics and a compact Offner imaging spectrograph. Based on the diffraction imaging theory, the multiscale fore-optics composed of a monocentric spherical lens and multi-channel microlens array is designed, over which panchromatic images with small FOV are of uniform image quality. And identical imaging spectrographs with a dimension less than 30 cubic millimeters and with a high spectral resolution of about 2nm are designed correspondingly. The presented imaging spectrometer works at the visible wavelength range which is from 400nm to 780nm. It is of a fast speed about F/2.4 and a compact configuration of only 200mm×300mm×300mm in dimension. But the smile and keystone distortions are negligible.

  2. ISOTOPE SEPARATORS

    DOEpatents

    Bacon, C.G.

    1958-08-26

    An improvement is presented in the structure of an isotope separation apparatus and, in particular, is concerned with a magnetically operated shutter associated with a window which is provided for the purpose of enabling the operator to view the processes going on within the interior of the apparatus. The shutier is mounted to close under the force of gravity in the absence of any other force. By closing an electrical circuit to a coil mouated on the shutter the magnetic field of the isotope separating apparatus coacts with the magnetic field of the coil to force the shutter to the open position.

  3. Spatial variability of streamwater chemistry and specific discharge during low flow periods - First results from snapshot sampling campaigns in thirteen Swiss catchments

    NASA Astrophysics Data System (ADS)

    Floriancic, Marius; Fischer, Benjamin; van Meerveld, Ilja

    2017-04-01

    Catchments consist of different landscape elements that store and release water differently. Few studies looked at which landscape elements contribute to streamflow during extended dry periods and whether these elements are similar in different catchments. We present a unique dataset from snapshot field campaigns in thirteen watersheds in Switzerland during low flow conditions in winter and summer 2016. The 10 to 110 km2 catchments varied from predominantly agricultural to alpine environments. In each campaign streamflow was measured and stream water was collected at a high spatial resolution using a nested sampling approach. Streamflow during the campaigns was less than the 65th percentile. We analyzed the water samples for the main ions and isotopic composition (Ca, Mg, SO4, F, NO3, Na, K, δ18O and δ2H) and compared the results with long-term datasets from the Swiss National Groundwater and River Monitoring Program (NAQUA and NADUF). For every sampling location, we calculated local and upslope catchment characteristics, including area, slope, flow length, topographic wetness index and elevation. Additionally, we determined land use, soil type and depth, geological and geomorphological characteristics from existing geodata for every sampling location. First analyses show that the spatial variation in water chemistry, isotopic composition and specific discharge is very high: Neighboring sampling locations could differ significantly in their specific discharge and isotopic and ion composition (up to a factor of 10), indicating different contributing sources. Water at the outlet was a mixture of water from different parts of the catchment. These first results suggest that the combination of snapshot water sampling and discharge measurements provides a valuable tool for identifying the spatial variability of contributing sources to streamflow. This information can then later be used to better constrain hydrological models and predict available water resources during

  4. Determination of 67Zn distribution in navy bean (Phaseolus vulgaris L.) after foliar application of 67Zn-lignosulfonates using isotope pattern deconvolution.

    PubMed

    Benedicto, Ana; Hernández-Apaolaza, Lourdes; Rivas, Inmaculada; Lucena, Juan J

    2011-08-24

    The improvement of Zn fertilizers requires new techniques to evaluate their efficacy. In this paper, the (67)Zn stable isotope was used as tracer of several Zn-lignosulfonate complexes to study the foliar-applied Zn uptake and distribution behavior in the plant, compared with ZnEDTA. Navy bean plants ( Phaseolus vulgaris L.) were grown hydroponically in a Zn-free nutrient solution, and six modified lignosulfonates and EDTA complexed with (67)Zn were used in foliar application in the young leaves as Zn sources. Zinc isotopes in roots, stems, and sprayed and unsprayed leaves were determined by ICP-MS, and signal interferences caused by the compounds of the digested vegetal samples were corrected. The mathematical procedure of isotope pattern deconvolution allowed the minimization of the uncertainty in the measured molar fractions of Zn from fertilizer or from natural sources. Significant differences in Zn use and distribution were observed among the fertilizers when the calculated concentrations of Zn from the fertilizer were compared, whereas they were unnoticeable attending to the total Zn in plant tissues, usually determined at the conventional studies. By foliar spray, higher Zn uptake and mobilization to leaves and stems were achieved with (67)ZnEDTA than with (67)Zn-LS complexes. The ultrafiltered LS and phenolated LS showed slightly better ability to provide Zn to the bean plants than the other LS. The foliar-applied Zn use and distribution in the plant were related with the stability of the Zn-lignosulfonates complexes. Those presenting the lower stability versus pH, but the highest complexing capacity, were slightly more suitable to supply foliar-applied Zn to navy beans.

  5. Compound-specific stable carbon isotope composition as a fingerprint for sediment transport: Reproducibility, homogeneity and application in a catchment of the Swiss plateau.

    NASA Astrophysics Data System (ADS)

    Birkholz, Axel; Niemann, Helge; Alewell, Christine

    2014-05-01

    A new field for the applications of compound-specific isotope analyses (CSIA) has opened in the recent years. The isotopic signature in fatty acids (FA) can be used to track sediment transport pathways from erosional areas to river systems. In this approach distinct FA d13C values of even numbered saturated and/or unsaturated FAs from soils are traced in suspended river sediments, ie. the place of deposition. CSIA has been shown to be particularly useful in catchment areas with C4 plant crops because, compared to the regularly occurring C3-plants, they are (naturally) depleted in 13C. However, in theory, all plant species even among C3 plants should inherit significant differences in their d13C of FAs. Thus, we tried to differentiate between source areas for suspended sediments from three different land use types: forest (C3 plants), grassland (C3 plants) and arable land (mixture of C3 and C4 plants). Statistical geo software (eg. Isosource) can be used to additionally model the spatial and temporal variability of erosion. We present d13C values of FAs from 8 erosion areas from the Enziwigger catchment of the Swiss plateau (Canton of Lucerne). Each area was assessed through randomised triplicate sampling to test the spatial homogeneity of each one. The homogeneity of a single sample, as well as the reproducibility of our measurements was tested by extracting and analysing the same sample bag in triplicates. We compare compound-specific stable isotope (CSSI) fingerprints of source areas to d13C-values of FAs from suspended sediments of two high-flow events and one base flow period at 3 different sites of the Enziwiger river (upstream, midstream, downstream).

  6. Stable isotopes in obesity research.

    PubMed

    Dolnikowski, Gregory G; Marsh, Julian B; Das, Sai Krupa; Welty, Francine K

    2005-01-01

    Obesity is recognized as a major public health problem. Obesity is a multifactorial disease and is often associated with a wide range of comorbidities including hypertension, non-insulin dependent (Type II) diabetes mellitus, and cardiovascular disease, all of which contribute to morbidity and mortality. This review deals with stable isotope mass spectrometric methods and the application of stable isotopes to metabolic studies of obesity. Body composition and total energy expenditure (TEE) can be measured by mass spectrometry using stable isotope labeled water, and the metabolism of protein, lipid, and carbohydrate can be measured using appropriate labeled tracer molecules.

  7. Calcium isotope analysis by mass spectrometry.

    PubMed

    Boulyga, Sergei F

    2010-01-01

    The variations in the isotopic composition of calcium caused by fractionation in heterogeneous systems and by nuclear reactions can provide insight into numerous biological, geological, and cosmic processes, and therefore isotopic analysis finds a wide spectrum of applications in cosmo- and geochemistry, paleoclimatic, nutritional, and biomedical studies. The measurement of calcium isotopic abundances in natural samples has challenged the analysts for more than three decades. Practically all Ca isotopes suffer from significant isobaric interferences, whereas low-abundant isotopes can be particularly affected by neighboring major isotopes. The extent of natural variations of stable isotopes appears to be relatively limited, and highly precise techniques are required to resolve isotopic effects. Isotope fractionation during sample preparation and measurements and instrumental mass bias can significantly exceed small isotope abundance variations in samples, which have to be investigated. Not surprisingly, a TIMS procedure developed by Russell et al. (Russell et al., 1978. Geochim Cosmochim Acta 42: 1075-1090) for Ca isotope measurements was considered as revolutionary for isotopic measurements in general, and that approach is used nowadays (with small modifications) for practically all isotopic systems and with different mass spectrometric techniques. Nevertheless, despite several decades of calcium research and corresponding development of mass spectrometers, the available precision and accuracy is still not always sufficient to achieve the challenging goals. The present article discusses figures of merits of presently used analytical methods and instrumentation, and attempts to critically assess their limitations. In Sections 2 and 3, mass spectrometric methods applied to precise stable isotope analysis and to the determination of (41)Ca are described. Section 4 contains a short summary of selected applications, and includes tracer experiments and the potential use

  8. Application of stable isotopes to identify problems in large-scale water transfer in Grand Canyon National Park.

    PubMed

    Ingraham, N L; Zukosky, K; Kreamer, D K

    2001-04-01

    Waters on, and below, the South Rim of the Grand Canyon were sampled for stable isotopic analysis to determine the hydrologic effects of the transcanyon pipeline. The transcanyon pipeline transports North Rim water discharging at Roaring Spring across the Grand Canyon to South Rim. Ultimately this water is discharged through the sewage treatment plant at the Clearwell Overflow wash on the surface expression of the Bright Angel Fault. The North Rim water is some 8 per mil more depleted in deltaD than most of the water issuing from springs on the South Rim except for that from Indian Garden Spring which lies below the Clearwell Overflow wash. Such a composition of Indian Garden Spring must come from discharged wastewater onthe rim, percolating downward approximately 1,000 m vertically through the Bright Angel Fault. The difference in stable isotopic composition of the North Rim water renders it not only traceable in Indian Garden Spring water, but the proportions may be determined as well which result in projecting an admixture of up to half the total discharge. Curiously however, Indian Garden Spring contains no appreciable amounts of the anions associated with wastewater. More recently, a leak in the transcanyon pipeline was discovered above Indian Garden Spring, suggesting that a portion of that spring's discharge may have its origin in water directly from the pipeline. Nevertheless, these data provide information relevant to the National Park Service policy of precluding anthropomorphic forces impacting national parks. In addition, the stable isotopic ratios of park water provide a mechanism to assess the potential for future degradation, as well as the origin of any future degradation, of the water quality of Indian Garden Spring.

  9. 77 FR 64143 - Manufacturer of Controlled Substances; Notice of Registration; Cambridge Isotope Lab

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-18

    ... Enforcement Administration Manufacturer of Controlled Substances; Notice of Registration; Cambridge Isotope..., Cambridge Isotope Lab, 50 Frontage Road, Andover, Massachusetts 01810, made application by renewal to the... registration of Cambridge Isotope Lab to manufacture the listed basic class of controlled substance...

  10. Urinary 19-norandrosterone purification by immunoaffinity chromatography: application to gas chromatography/combustion/isotope ratio mass spectrometric analysis.

    PubMed

    Desroches, M C; Mathurin, J C; Richard, Y; Delahaut, P; de Ceaurriz, J

    2002-01-01

    The detection of exogenous 19-norandrosterone (19-NA) in urines was investigated by using gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). 19-NA is, for the first time to our knowledge, isolated from urinary matrix by specific immunoaffinity chromatography (IAC) before analysis. The sample preparation consisted of a preliminary purification of urine by solid-phase extraction after hydrolysis by beta-glucuronidase. Unconjugated 19-NA was thus isolated by IAC and directly analysed by GC/C/IRMS. Optimisation of IAC purification was achieved and the reliability of the technique for anti-doping control is discussed.

  11. The application of stable isotope tracers to evaluate the extent of sulfate reduction in a BTEX-contaminated aquifer

    NASA Astrophysics Data System (ADS)

    Knoeller, K.; Weise, S. M.; Goedeke, S.; Weiss, H.; Schirmer, M.

    2003-04-01

    Due to its contribution to the mineralization of organic contaminants to carbon dioxide and water, bacterial sulphate reduction may be an important process for long-term natural attenuation of contaminated aquifers. A Quaternary aquifer, partly contaminated with various BTEX-species, has been investigated by high-resolution groundwater sampling to evaluate the potential and extent of bacterial sulphate reduction. The aquifer, located on the site of a former hydrogenation plant near the town of Zeitz (Saxonia-Anhalt, Germany), mainly consists of sandy and clayey deposits from the Pleistocene Elster-glacial and has a thickness of 5--10 m. More than 100 groundwater samples have been analyzed for both δ34S-SO_4 and δ18O-SO_4. The isotopic composition of the dissolved groundwater sulphate showed a very heterogeneous regional distribution that cannot be explained by a simple mixing pattern. Generally, δ34S-sulphate values ranged from -1 to +48 ppm (VCDT). Smaller variations (+1 ...+16 ppm VSMOW) were observed for δ18O-sulphate. Sulphur from historic atmospheric deposition appears to be the predominant sulphate source for the regional groundwater in the aquifer. Relatively low δ18O-sulphate values in some samples suggest that part of the sulphate may be derived from the oxidation of sedimentary pyrite. Increasing δ34S values and simultaneously decreasing sulphate concentrations along the groundwater flow path in the northern outflow of the contaminant plume indicate the occurrence of bacterial sulphate reduction. While sulphate concentration drop from over 300 to less than 20 mg/L, δ34S values increase up to +45 ppm (VCDT). Using a Rayleigh model for the reduction process, an isotope enrichment factor (ɛ) of ca. -12 ppm was obtained. In contrast, no enrichment of 18O was observed. This is due to the specific reaction conditions that inhibit the oxygen isotope exchange between sulphate and water during the reduction process and hence disable the 18O enrichment in

  12. Fast and precise method for Pb isotope ratio determination in complex matrices using GC-MC-ICPMS: application to crude oil, kerogen, and asphaltene samples.

    PubMed

    Sanabria-Ortega, Georgia; Pécheyran, Christophe; Bérail, Sylvain; Donard, Olivier F X

    2012-09-18

    A new method to determine Pb isotope ratio without ion-exchange-matrix separation is proposed. After acid digestion, Pb was ethylated to Et(4)Pb, separated from the digested solution (black shale, asphaltene, crude oil and kerogen) by extraction in isooctane, and then injected into a gas chromatograph coupled to a multicollector inductively coupled plasma mass spectrometer. Seven isotopes ((202)Hg, (203)Tl, (204)Pb, (205)Tl, (206)Pb, (207)Pb, (208)Pb) were monitored simultaneously with peak duration of 23 s. GC elution was operated under wet plasma conditions where a thallium standard solution was introduced to the mass spectrometer for mass bias correction. The total time of the procedure (sample preparation and analysis, after acid digestion) was reduced by a factor of 15 compared to conventional-continuous sample introduction. Data treatment was carried out using the linear regression slope method. Mass bias was corrected using the double correction method (first thallium normalization followed by classical bracketing). For the (208/206)Pb and (207/206)Pb ratios, precision (2RSD(EXT), n = 21) was 49 and 69 ppm, and the bias between experimental results and reference values was better than 0.0033 and 0.0007 ‰, when injecting 1.2 ng of ethylated Pb SRM NIST 981 solution. Results obtained by this method were validated by comparison with those obtained via conventional-continuous sample introduction. The applicability of this approach was demonstrated with the analysis of black shale, asphaltene, crude oil and kerogen samples.

  13. [On-line method for measurement of the carbon isotope ratio of atmospheric methane and its application to atmosphere of Yakela condensed gas field].

    PubMed

    Tang, Jun-Hong; Bao, Zheng-Yu; Xiang, Wu; Qiao, Sheng-Ying; Li, Bing

    2006-01-01

    An on-line method for measurement of the 13C/12C ratio of methane by a gas chromatography/high-temperature conversion/ isotope ratio mass spectrometry (GC/C/MS) technique was developed. This method is less laborious, more rapid (45 min), of high precision (+/- 0.4 x 10(-3)) and by using a small amount of sample (about 200 mL of atmosphere). Its application to isotopic characterization, and hence methane source identification, was demonstrated by examination of atmosphere sample collected in Yakela condensed gas field, China. The average 13C/12C ratio of atmospheric methane in Yakela field was -45.0 x 10(-3) heavier by 1.2 x 10(-3) -2.0 x 10(-3) than the global average. This is caused by seepage and diffusing of methane from Yakela condensed gas reservoir. The concentrations of atmospheric methane in daytimes are found to be lower than those in nighttimes, and the corresponding 13C/12C ratios in daytimes are lighter compared to those in nighttimes, a phenomena probably caused by the fact that a small part of methane from Yakela condensate reservoir is consumed in soil's surface under sunlight.

  14. A calibration of the triple oxygen isotope fractionation in the SiO2-H2O system and applications to natural samples

    NASA Astrophysics Data System (ADS)

    Sharp, Z. D.; Gibbons, J. A.; Maltsev, O.; Atudorei, V.; Pack, A.; Sengupta, S.; Shock, E. L.; Knauth, L. P.

    2016-08-01

    It is now recognized that variations in the Δ17O of terrestrial materials resulting from purely mass dependent fractionations, though small, have geological significance. In this study, the δ18O and δ17O values of selected low temperature quartz and silica samples were measured in order to derive the quartz-water fractionation-temperature relationship for the three oxygen isotope system. A 18O/16O quartz-water fractionation equation valid for all temperatures was generated from published high temperature exchange experiments and low temperature empirical estimates and is given by 1000ln αqz-H2O 18O /16O =4.20 (0.11) ×106/T2 - 3.3 (0.2) × 1000/T (T in Kelvins). The equilibrium δ17O-δ18O relationship is given by the equation lnα17O/16O = θlnα18O/16O . The variation of θ with temperature for the quartz-water system was determined empirically using low temperature marine diatoms, microcrystalline quartz and a modern sinter sample. A best fit to the data give the equation θSiO2-H2O = -(1.85 ± 0.04)/T + 0.5305 , indistinguishable from an earlier theoretical estimate. Application of the quartz-water triple isotope system to low temperature samples provides constraints on both temperature and composition of the water with which the silica last equilibrated. Authigenic quartz crystallization temperatures cluster around 50 °C, which are lower than many previous estimates. The combined δ18O and δ17O values of samples considered to be in equilibrium with ocean or meteoric waters can be used to estimate both formation temperatures and the δ18O value of the meteoric water. Unlike other multiple isotopes systems, such as combined H and O isotopes in cherts, the oxygen source and diagenetic potential for both 17O/16O and 18O/16O ratios are identical, simplifying interpretations from ancient samples.

  15. C and N Isotopes in Ostrich Eggshell as Proxies of Paleovegetation and Paleoprecipitation: Extraction, Preservation, and Application to Pleistocene Archaeological Samples

    NASA Astrophysics Data System (ADS)

    Niespolo, E. M.; Sharp, W. D.; Tryon, C. A.; Faith, J. T.; Miller, M.; Dawson, T. E.

    2015-12-01

    Paleoenvironmental change is commonly invoked as a factor in the development of modern human behaviors and the successful expansion of H. sapiens out of Africa, and paleoenvironmental information from archaeological sequences is central to addressing such questions. Ostrich eggshell (OES) are common in many African archaeological sequences and may be dated by 14C and U-series methods. In modern ratite eggshells (large flightless birds including the ostrich and emu), the δ13C in eggshell calcite and the δ13C and δ15N in eggshell organic fractions have been shown to vary systematically across climate gradients in South Africa and Australia with δ15N varying inversely with mean annual precipitation, and δ13C varying with the C isotopes of vegetation (1,2). Thus, if primary C and N isotopic signatures are preserved, assemblages of OES can provide dated records of paleovegetation and paleoprecipitation at archaeological sites. Since the C isotopic fractionation between calcite and eggshell organics is constant in modern OES (Δ13Ccalcite-organic = 14.7 ± 1.3‰) (3), evaluating that offset in ancient OES provides a test for preservation of primary isotopic signatures. Johnson et al. (3) showed that OES from Equus Cave (South Africa) retained the expected fractionation for up to 17 ka. We present a new protocol to extract C and N of OES organics for online analysis that preserves pristine δ13C and δ15N values and C and N contents. We find that using sodium hydroxide (NaOH), common to many bone collagen extraction procedures, destroys and degrades the organic component of OES, resulting in low C and N and altered δ13C and δ15N values. Analysis of a series of OES samples directly dated by 14C and U-series from the GvJm-22 rockshelter (Lukenya Hill, Kenya) (4,5) will demonstrate the first application of this protocol to OES from the last ~50,000 yr. 1. Johnson, B.J. et al. (1998) Geochim. Cosmochim. Acta 62, 2451-2461. 2. Newsome, S.D. et al. (2011) Oecologia 167

  16. Single-snapshot 2D color measurement by plenoptic imaging system

    NASA Astrophysics Data System (ADS)

    Masuda, Kensuke; Yamanaka, Yuji; Maruyama, Go; Nagai, Sho; Hirai, Hideaki; Meng, Lingfei; Tosic, Ivana

    2014-03-01

    Plenoptic cameras enable capture of directional light ray information, thus allowing applications such as digital refocusing, depth estimation, or multiband imaging. One of the most common plenoptic camera architectures contains a microlens array at the conventional image plane and a sensor at the back focal plane of the microlens array. We leverage the multiband imaging (MBI) function of this camera and develop a single-snapshot, single-sensor high color fidelity camera. Our camera is based on a plenoptic system with XYZ filters inserted in the pupil plane of the main lens. To achieve high color measurement precision of this system, we perform an end-to-end optimization of the system model that includes light source information, object information, optical system information, plenoptic image processing and color estimation processing. Optimized system characteristics are exploited to build an XYZ plenoptic colorimetric camera prototype that achieves high color measurement precision. We describe an application of our colorimetric camera to color shading evaluation of display and show that it achieves color accuracy of ΔE<0.01.

  17. Converting isotope ratios to diet composition - the use of mixing models - June 2010

    EPA Science Inventory

    One application of stable isotope analysis is to reconstruct diet composition based on isotopic mass balance. The isotopic value of a consumer’s tissue reflects the isotopic values of its food sources proportional to their dietary contributions. Isotopic mixing models are used ...

  18. Forensic Stable Isotope Biogeochemistry

    NASA Astrophysics Data System (ADS)

    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.

  19. Compelling Research Opportunities using Isotopes

    SciTech Connect

    2009-04-23

    Isotopes are vital to the science and technology base of the US economy. Isotopes, both stable and radioactive, are essential tools in the growing science, technology, engineering, and health enterprises of the 21st century. The scientific discoveries and associated advances made as a result of the availability of isotopes today span widely from medicine to biology, physics, chemistry, and a broad range of applications in environmental and material sciences. Isotope issues have become crucial aspects of homeland security. Isotopes are utilized in new resource development, in energy from bio-fuels, petrochemical and nuclear fuels, in drug discovery, health care therapies and diagnostics, in nutrition, in agriculture, and in many other areas. The development and production of isotope products unavailable or difficult to get commercially have been most recently the responsibility of the Department of Energy's Nuclear Energy program. The President's FY09 Budget request proposed the transfer of the Isotope Production program to the Department of Energy's Office of Science in Nuclear Physics and to rename it the National Isotope Production and Application program (NIPA). The transfer has now taken place with the signing of the 2009 appropriations bill. In preparation for this, the Nuclear Science Advisory Committee (NSAC) was requested to establish a standing subcommittee, the NSAC Isotope Subcommittee (NSACI), to advise the DOE Office of Nuclear Physics. The request came in the form of two charges: one, on setting research priorities in the short term for the most compelling opportunities from the vast array of disciplines that develop and use isotopes and two, on making a long term strategic plan for the NIPA program. This is the final report to address charge 1. NSACI membership is comprised of experts from the diverse research communities, industry, production, and homeland security. NSACI discussed research opportunities divided into three areas: (1) medicine

  20. Symptoms: Personal snapshots of anxiety disorders | NIH MedlinePlus the Magazine

    MedlinePlus

    ... of this page please turn Javascript on. Feature: Phobias and Anxiety Disorders Symptoms: Personal snapshots of anxiety ... And it was scary.” Social Anxiety Disorder (Social Phobia): "In any social situation, I felt fear. I ...

  1. Energy Transition Initiative, Island Energy Snapshot - British Virgin Islands (Fact Sheet)

    SciTech Connect

    Not Available

    2015-03-01

    This profile provides a snapshot of the energy landscape of the British Virgin Islands (BVI), one of three sets of the Virgin Island territories in an archipelago making up the northern portion of the Lesser Antilles.

  2. Energy Transition Initiative: Island Energy Snapshot - Saint Martin/Sint Maarten

    SciTech Connect

    2015-09-01

    This profile provides a snapshot of the energy landscape of the northeast Caribbean island Saint Martin. The island is divided between two nations, France in the north (Saint-Martin) and the Netherlands in the south (Sint Maarten).

  3. Cancer Snapshots: Facts and statistics for each cancer type or topic

    Cancer.gov

    Snapshots provide key information on disease incidence and mortality, NCI funding trends, relevant research activities, and recent scientific advances related to specific types of cancer and on special populations and scientific topics.

  4. Cancer Snapshots: Facts and statistics for each cancer type or topic

    Cancer.gov

    Snapshots provide key information on disease incidence and mortality, NCI funding trends, relevant research activities, and recent scientific advances related to specific types of cancer and on special populations and scientific topics.

  5. Energy Transition Initiative: Island Energy Snapshot - Puerto Rico (Fact Sheet); NREL(National Renewable Energy Laboratory)

    SciTech Connect

    2015-03-01

    This profile provides a snapshot of the energy landscape of the Commonwealth of Puerto Rico - a U.S. territory located about 60 miles east of the Dominican Republic and directly west of the U.S. Virgin Islands.

  6. A new approach for deciphering between single and multiple accumulation events using intra-tooth isotopic variations: Application to the Middle Pleistocene bone bed of Schöningen 13 II-4.

    PubMed

    Julien, Marie-Anne; Rivals, Florent; Serangeli, Jordi; Bocherens, Hervé; Conard, Nicholas J

    2015-12-01

    It is often difficult to differentiate between archaeological bonebeds formed by one event such as a mass kill of a single herd, and those formed by multiple events that occurred over a longer period of time. The application of high temporal resolution studies such as intra-tooth isotopic profiles on archaeological mammal cohorts offers new possibilities for exploring this issue, allowing investigators to decipher between single and multiple accumulation events. We examined (18)O and (13)C isotopic variations from the enamel carbonate of 23 horse third molars from the Middle Pleistocene archaeological site of Schöningen. We employed a new approach to investigate processes of fossil accumulation that uses both bulk and intra-tooth isotopic variations and takes into account animal behavior, age at death and dental development to test the degree of isotopic affinity of animals from the same fossil assemblage. Oxygen and carbon isotope bulk values indicate that the horses from Schöningen 13 II-4 experienced relatively similar climatic and dietary regimes. Inter-individual differences of the bulk values of the horses sampled in the current study present nevertheless inter-individual variability similar to individuals from multi-layered localities. In addition, the intra-tooth isotopic variation of specimens of the same age at death seems to indicate that the studied cohort corresponds to a mix of individuals that recorded both similar and different isotopic histories. Finally, the conditions recorded in the isotopic signal shortly before death (i.e., for teeth not fully mineralized) varied between sampled individuals, suggesting possible differences in the seasonality of death. Considering those results, we discuss the possibility that the horses from Schöningen 13 II-4 correspond to an accumulation of different death events.

  7. Stable carbon isotope analysis of coprocessing materials

    SciTech Connect

    Winschel, R.A.; Lancet, M.S.; Burke, F.P.

    1991-04-01

    This is the final report which was a thirty-four month project conducted to develop and demonstrate stable carbon isotope analysis as a method to quantitatively distinguish the source of carbon in products of coal/petroleum coprocessing. The work included assessing precision, accuracy, the range of application and the significance of selective isotopic fractionation effects. A method was devised to correct for selective isotopic fractionation errors. The method was demonstrated through application with samples from twelve continuous-unit coprocessing tests. A data base of carbon isotope analyses is appended. 21 refs.

  8. Heavy atom isotope effects on enzymatic reactions

    NASA Astrophysics Data System (ADS)

    Paneth, Piotr

    1994-05-01

    The theory of isotope effects, which has proved to be extremely useful in providing geometrical details of transition states in a variety of chemical reactions, has recently found an application in studies of enzyme-catalyzed reactions. These reactions are multistep in nature with few steps being partially rate-limiting, thus interpretation of these isotope effects is more complex. The theoretical framework of heavy-atom isotope effects on enzymatic reactions is critically analyzed on the basis of recent results of: carbon kinetic isotope effects on carbonic anhydrase and catalytic antibodies; multiple carbon, deuterium isotope effects on reactions catalyzed by formate decarboxylase; oxygen isotope effects on binding processes in reactions catalyzed by pyruvate kinase; and equilibrium oxygen isotope effect on binding an inhibitor to lactate dehydrogenase. The advantages and disadvantages of reaction complexity in learning details of formal and molecular mechanisms are discussed in the examples of reactions catalyzed by phosphoenolpyruvate carboxylase, orotidine decarboxylase and glutamine synthetase.

  9. "Phase-Enhanced" 3D Snapshot ISAR Imaging and Interferometric SAR

    DTIC Science & Technology

    2009-12-28

    document when it is no longer needed. Massachusetts Institute of Technology Lincoln Laboratory ttPhase-Lnhanced,, 3D Snapshot ISAR Imaging and...inverse synthetie aperture radar ( ISAR ) images based on recent developments in high resolution spectral estimation theory. Because this technique requires...the radar sensor. This report develops a framework based on 3D snapshot imaging of sparse angle sectors of ISAR data, extending these results to 3D

  10. Hydrograph separation using stable isotopes: Review and evaluation

    NASA Astrophysics Data System (ADS)

    Klaus, J.; McDonnell, J. J.

    2013-11-01

    We reviewed isotope hydrograph separation studies.We examine methods, applications, and limitations.We summarize factors that control the event/pre-event water contributions.We outline new possible research avenues in isotope hydrograph separation.

  11. Application of strontium isotope measurements to trace sediment sources in an upstream agricultural catchment (Loire River basin, France)

    NASA Astrophysics Data System (ADS)

    Le Gall, Marion; Evrard, Olivier; Thil, François; Foucher, Anthony; Salvador-Blanes, Sébastien; Cerdan, Olivier; Ayrault, Sophie

    2015-04-01

    Soil erosion is recognized as one of the main processes of land degradation in agricultural areas. It accelerates the supply of sediment to the rivers and degrades water quality. To limit those impacts and optimize management programs in such areas, sources of sediment need to be identified and sediment transport to be controlled. Here, we determined the sources of suspended sediment in the Louroux (24 km², French Loire River basin), a small catchment representative of lowland cultivated environments of Northwestern Europe. In this catchment, channels have been reshaped and 220 tile drain outlets have been installed over the last several decades. As a result, soil erosion and sediment fluxes have increased drastically. The variation of 87Sr/86Sr ratios, driven by the weathering of rocks with different ages and chemical composition, may reflect the mixing of different sediment sources. Strontium isotopic ratios (87Sr/86Sr) were therefore determined in potential soil sources, suspended particulate matter (SPM) and a sediment core sampled in the Louroux Pond at the catchment outlet. Soil, SPM and core samples displayed significantly different isotopic signatures. 87Sr/86Sr ratios in soil samples varied from 0.712763 to 0.724631 ± 0.000017 (2σ, n=20). Highest values were observed in silicic parts of the catchment whereas the lower values were identified in a calcareous area close to the Louroux Pond. 87Sr/86Sr ratios in SPM (0.713660 to 0.725749 ± 0.000017, 2σ, n=20) plotted between the soil and sediment core (0.712255 to 0.716415 ± 0.000017, 2σ, n=12), suggesting the presence of particles originating from at least two different lithological sources, i.e. silicic rocks and carbonate material. Variations in 87Sr/86Sr ratios in the outlet core sample were used to reconstruct the sedimentary dynamics in the catchment during the last decades. These results will guide the future implementation of appropriate management practices aiming to reduce erosion in upstream

  12. Applications of radon and radium isotopes to determine submarine groundwater discharge and flushing times in Todos os Santos Bay, Brazil.

    PubMed

    Hatje, Vanessa; Attisano, Karina Kammer; de Souza, Marcelo Friederichs Landim; Mazzilli, Barbara; de Oliveira, Joselene; de Araújo Mora, Tamires; Burnett, William C

    2017-08-16

    Todos os Santos Bay (BTS) is the 2nd largest bay in Brazil and an important resource for the people of the State of Bahia. We made measurements of radon and radium in selected areas of the bay to evaluate if these tracers could provide estimates of submarine groundwater discharge (SGD) and flushing times of the Paraguaçu Estuary and BTS. We found that there were a few areas along the eastern and northeastern shorelines that displayed relatively high radon and low salinities, indicating possible sites of enhanced SGD. A time-series mooring over a tidal cycle at Marina do Bonfim showed a systematic enrichment of the short-lived radium isotopes (223)Ra and (224)Ra during the falling tide. Assuming that the elevated radium isotopes were related to SGD and using measured radium activities from a shallow well at the site, we estimated groundwater seepage at about 70 m(3)/day per unit width of shoreline. Extrapolating to an estimated total shoreline length provided a first approximation of total (fresh + saline) SGD into BTS of 300 m(3)/s, about 3 times the average river discharge into the bay. Just applying the shoreline lengths from areas identified with high radon and reduced salinity results in a lower SGD estimate of 20 m(3)/s. Flushing times of the Paraguaçu Estuary were estimated at about 3-4 days based on changing radium isotope ratios from low to high salinities. The flushing time for the entire BTS was also attempted using the same approach and resulted in a surprisingly low value of only 6-8 days. Although physical oceanographic models have proposed flushing times on the order of months, a simple tidal prism calculation provided results in the range of 4-7 days, consistent with the radium approach. Based on these initial results, we recommend a strategy for refining both SGD and flushing time estimates. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Pb isotopic systematics in dolomitic rocks and their application to geochronology, provenance, and fluid-rock interaction

    SciTech Connect

    Hoff, J.A.

    1992-01-01

    In the Burlington-Keokuk Fms. (Miss.; Iowa-Illinois) the two major dolomite generations (dolomites I and II) exhibit a difference in initial [sup 206]Pb/[sup 204]Pb. This difference is used to constrain the sources of dolomitizing fluids. The composition of dolomite I is consistent with a marine source for Pb, which had an ultimate derivation from rocks uplifted along eastern North America during the Acadian Orogeny. In contrast, dolomite II has a significantly higher [sup 206]Pb/[sup 204]Pb character. Fluid-rock modeling is used to show that dolomite II could have formed by interaction of dolomite I with a saline fluid that had previously interacted with underlying sedimentary units. The Pb isotopic data indicates that this saline fluid did not derive its Pb from the more radiogenic (basement ) sources samples by the ore solutions that precipitated the MVT deposits in the region. Whole-rock dolostones from both the Burlington-Keokuk Fms. and the Wahoo Em. (Penn.; Prudhoe Bay, Alaska) are enriched in U (up to 67 ppm) relative to their constituent dolomites (<2 ppm). The enrichment of U, high [mu]'s ([sup 238]U/[sup 204]Pb), and low k's ([sup 232]Th/[sup 238]U) exhibited by wholerocks from both sequences suggest that U was mobile relative to Th and Pb during diagenesis. The timing of U-enrichment/mobility are constrained using Pb isotopic data. Despite high [mu]'s, Burlington-Keokuk Fms. dolostones are relatively unradiogenic. Calculations require U-enrichment to be relatively recent (i.e., <5 Ma). In contrast, dolostones from the Wahoo Fm. are relatively uranogenic and the spread of isotopic data yields Pb-Pb and U-Pb ages of [approximately]260 Ma. These ages are consistent with U enrichment concurrent with the development of a regional unconformity during the Permian. In both the Burlington-Keokuk and Wahoo Fms., U was probably transported as U(VI) complexes in near surface oxidized waters and enriched in local reducing zones adjacent to exposure surfaces.

  14. Isotopic analysis of planetary solids

    NASA Astrophysics Data System (ADS)

    Tulej, M.; Riedo, A.; Neuland, M.; Meyer, S.; Wurz, P.

    2013-09-01

    Isotopic analysis of planetary surfaces is of considerable interest for planetology. Studies of isotope composition can deliver information on radio-isotope chronology of planetary soil/regolith, an insight to processes that altered planetary surface (space weathering) or on possible biogenic processes that occurred or still occur on the planet. Mass spectrometry is a well-suited method that delivers accurate and precise isotope composition. Among other instruments (LAZMA and LAMS), the miniature laser ablation/ionisation mass analyser, LMS developed in Bern for in situ space research can be used to measure the elemental and isotopic composition of planetary solids. LMS support mass spectrometric investigation with a mass resolution of m/Δm≈500-1500, dynamic range of at least 8 decades and detection sensitivity of ~10 ppb. Current studies of various solid materials and standard reference materials show that isotope composition can be conducted with an accuracy and precision at per mill level if the isotope concentration exceeds 10-100 ppm. Implications of the studies for in situ application are discussed.

  15. Application of the SILAC (stable isotope labelling with amino acids in cell culture) technique in quantitative comparisons for tissue proteome expression.

    PubMed

    Xu, Yuhuan; Liang, Shufang; Shen, Guobo; Xu, Xuejiao; Liu, Qingping; Xu, Zhizhong; Gong, Fengming; Tang, Minghai; Wei, Yuquan

    2009-07-06

    Stable isotope labelling has recently become a popular tool for the quantitative profiling of the proteome, especially the emergence and development of the SILAC (stable isotope labelling with amino acids in cell culture) technique. Here we have expanded the application of SILAC to comparison of the relative protein expression levels between two different states of tissues based on cultured cells with [2H]leucine labelling as an internal standard in mass spectra. The SILAC ratio of tissue proteins versus labelled cells was determined by the calculation of peak intensity of the pair of labelled and unlabelled peptide fragment ions from the mass spectra, and the relative expression level of proteins in two groups of tissues was estimated by calculating the ratio of their SILAC ratio. To validate our [2H]leucine-based differential proteome analysis for tissues, we successfully compared two known proteins, one up-regulated vimentin and one down-regulated enoyl-CoA hydratase in human renal cancerous tissues versus human normal kidney tissues, which was previously confirmed by other groups using conventional two-dimensional PAGE analysis. Furthermore, we identified a previously unknown down-regulated protein, COX4I1 (cytochrome c oxidase subunit 4 isoform 1), in renal carcinoma tissues by this [2H]leucine-based quantitative proteomics method, which was also validated by immunohistochemistry and Western-blot analysis. In conclusion, the application of the [2H]leucine-based quantitative technique can be effectively expanded to comparison of the expression levels for the tissue proteome at different states, which would help us to identify new candidate biomarkers for tumours.

  16. Isotope fractionation

    NASA Astrophysics Data System (ADS)

    Bell, Peter M.

    A rash of new controversy has emerged around the subject of mass-independent isotope fractionation effects, particularly in the case of the oxygen isotopes. To be sure, the controversy has been around for awhile, but it has been given new impetus by the results of a recent study by Mark H. Thiemens and John E. Heidenreich III of the University of California, San Diego (Science, March 4, 1983).Gustav Arrhenius has been trying to convince the planetary science community that chemical effects in isotope fractionation processes could explain observations in meteorites that appear to be outside of the traditionally understood mass-dependent fractionations (G. Arrhenius, J . L. McCrumb, and N. F. Friedman, Astrophys. Space Sci, 65, 297, 1974). Robert Clayton had made the basic observations of oxygen in carbonaceous chondrites that the slope of the δ17 versus δ18 line was 1 instead of the slope of ½ characteristic of terrestrial rocks and lunar samples (Ann. Rev. Nucl. Part. Sci., 28, 501, 1978). The mass-independent effects were ascribed to the apparent contribution of an ancient presolar system component of O16.

  17. Forensic applications of stable isotope analysis: case studies of the origins of water in mislabeled beer and contaminated diesel fuel.

    PubMed

    Papesch, Wolfgang; Horacek, Micha

    2009-06-01

    This paper describes the use of oxygen (18O) isotope analysis of water contained in two different materials--beer and diesel fuel--involved in the resolution of two separate cases. In the first case study, it was possible to demonstrate that a sample of beer labelled as premium brand in fact belonged to a cheap brand. The second case related to the contamination of diesel fuel from a service station. The diesel fuel contained visible amounts of water, which caused vehicles that had been filled up with it to become defective. For insurance purposes, it was necessary to determine the source of water. The delta18O values for the water of nearly all samples of diesel was close to the delta18O of local tap water at the filling station.

  18. On-line sulfur isotope analysis of organic material by direct combustion: Preliminary results and potential applications

    USGS Publications Warehouse

    Kester, C.L.; Rye, R.O.; Johnson, C.A.; Schwartz, C.H.; Holmes, C.H.

    2001-01-01

    Sulfur isotopes have received little attention in ecology studies because plant and animal materials typically have low sulfur concentrations (< 1 wt.%) necessitating labor-intensive chemical extraction prior to analysis. To address the potential of direct combustion of organic material in an elemental analyzer coupled with a mass spectrometer, we compared results obtained by direct combustion to results obtained by sulfur extraction with Eschka's mixture. Direct combustion of peat and animal tissue gave reproducibility of better than 0.5??? and on average, values are 0.8??? higher than values obtained by Eschka extraction. Successful direct combustion of organic material appears to be a function of sample matrix and sulfur concentration. Initial results indicate that direct combustion provides fast, reliable results with minimal preparation. Pilot studies underway include defining bear diets and examining fluctuations between freshwater and brackish water in coastal environments.

  19. Stable nitrogen and carbon isotopes in sediments and biota from three tropical marine food webs: Application to chemical bioaccumulation assessment.

    PubMed

    Zhang, Hui; Teng, Yun; Doan, Tra Thi Thanh; Yat, Yun Wei; Chan, Sheot Harn; Kelly, Barry C

    2017-09-01

    Studies of trophodynamics and contaminant bioaccumulation in tropical marine ecosystems are limited. The present study employed stable isotope and trace contaminant analysis to assess sources of primary productivity, trophic interactions, and chemical bioaccumulation behavior in 2 mangrove food webs and 1 offshore coastal marine food web in Singapore. Samples of sediment, phytoplankton, mangrove leaves, clams, snails, crabs, worms, prawns, and fishes were analyzed for stable carbon and nitrogen isotope values, as well as concentrations of persistent organic pollutants. In the mangrove food webs, consumers exhibited similar δ(13) C values, probably because of the well-mixed nature of these systems. However, the 2 primary consumers (common nerite and rodong snail) exhibited distinct δ(13) C values (-21.6‰ vs -17.7‰), indicating different carbon sources. Fish from Singapore Strait exhibited similar δ(13) C values, indicating common carbon sources in this offshore marine food web. The highest trophic level was found in glass perchlet (trophic level = 3.3) and tilapia (trophic level = 3.4) in the 2 mangrove food webs and grunter (trophic level = 3.7) in the Singapore Strait food web. Concentrations of polychlorinated biphenyl (PCB 153) and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) concentrations ranged from 0.9 to 84.6 ng/g lipid weight and from <0.2 to 267.4 ng/g lipid weight, respectively. The trophic magnification factors of PCB 153 and p,p'-DDE ranged between 1.63 and 4.62, indicating biomagnification in these tropical marine food webs. The findings provide important information that will aid future chemical bioaccumulation assessment initiatives. Environ Toxicol Chem 2017;36:2521-2532. © 2017 SETAC. © 2017 SETAC.

  20. Application of stable isotope measurements and microbiological analysis for detecting methanogenic activity in a temperate forest wetland

    NASA Astrophysics Data System (ADS)

    Itoh, M.; Katsuyama, C.; Kondo, N.; Ohte, N.; Kato, K.

    2009-12-01

    Generally, forest soils act as a sink for methane (CH4). However, wetlands in riparian zones are recently reported to be “hot spots” of CH4 emissions, especially in forests under a humid climate. To understand how environmental conditions (i.e. hydrological and/or geomorphic condition) control on CH4 production, we investigated both methanogenic pathways (CO2/H2 reduction and acetate fermentation) and metahanogenic microbial communities in a wetland in a temperate forest catchment, central Japan. We used stable carbon isotopic analysis for detecting change in methanogenic pathways, and applied microbiological analysis for understanding the structure of methanogenic community. CH4 emission rates in wetland were strongly dependent on soil temperatures, and were highest in summer and lowest in winter. δ13CO2 increased with CH4 production in every summer, suggesting preferential use of 12CO2 as substrate for CO2/H2 reduction methanogenesis during high CH4 production period. δ13CH4 also increased in summer with δ13CO2. δ13CH4 changed more wildly than δ13CO2 did in summer with normal precipitation when CH4 production was strongly activated under high temperature and high groundwater table condition. This indicates increase in acetoclastic methanogenesis under hot and wet condition, considering that acetclastic methnogens produce heavier CH4 than that from CO2/H2 reducing pathway. Methanogen community composition estimated by cloning and sequence analyses implied that both acetoclastic and CO2/H2 reducing methanogens prevailed in wetland soil sampled in summer. This was consistent with the results of isotope measuremaents. Our results contribute to understand fully how the CH4 production changes with environmental conditions, with considering the activities of both main methanogenic pathway (from CO2 and acetate).

  1. Selective photoionisation of lutetium isotopes

    SciTech Connect

    D'yachkov, Aleksei B; Kovalevich, S K; Labozin, Valerii P; Mironov, Sergei M; Panchenko, Vladislav Ya; Firsov, Valerii A; Tsvetkov, G O; Shatalova, G G

    2012-10-31

    A three-stage laser photoionisation scheme intended for enriching the {sup 176}Lu isotope from natural lutetium was considered. An investigation was made of the hyperfine structure of the second excited state 5d6s7s {yields} {sup 4}D{sub 3/2} with an energy of 37194 cm{sup -1} and the autoionisation state with an energy of 53375 cm{sup -1} of the {sup 176}Lu and {sup 175}Lu isotopes. The total electron momentum of the autoionisation level and the constant A of hyperfine magnetic interaction were determined. Due to a small value of the isotopic shift between {sup 176}Lu and {sup 175}Lu, appreciable selectivity of their separation may be achieved with individual hyperfine structure components. The first tentative enrichment of the 176Lu isotope was performed to a concentration of 60 % - 70 %. (laser applications and other topics in quantum electronics)

  2. Capturing snapshots of APE1 processing DNA damage

    SciTech Connect

    Freudenthal, Bret D.; Beard, William A.; Cuneo, Matthew J.; Dyrkheeva, Nadezhda S.; Wilson, Samuel H.

    2015-10-12

    DNA apurinic-apyrimidinic (AP) sites are prevalent noncoding threats to genomic stability and are processed by AP endonuclease 1 (APE1). APE1 incises the AP-site phosphodiester backbone, generating a DNA-repair intermediate that is potentially cytotoxic. The molecular events of the incision reaction remain elusive, owing in part to limited structural information. Here we report multiple high-resolution human APE1-DNA structures that divulge new features of the APE1 reaction, including the metal-binding site, the nucleophile and the arginine clamps that mediate product release. We also report APE1-DNA structures with a T-G mismatch 5' to the AP site, representing a clustered lesion occurring in methylated CpG dinucleotides. Moreover, these structures reveal that APE1 molds the T-G mismatch into a unique Watson-Crick-like geometry that distorts the active site, thus reducing incision. Finally, these snapshots provide mechanistic clarity for APE1 while affording a rational framework to manipulate biological responses to DNA damage.

  3. Snapshot polarimeter based on the conical refraction phenomenon

    NASA Astrophysics Data System (ADS)

    Peinado, Alba; Lizana, Angel; Turpin, Alex; Estévez, Irene; Iemmi, Claudio; Kalkanjiev, Todor K.; Mompart, Jordi; Campos, Juan

    2015-06-01

    A complete and punctual Stokes polarimeter based on the conical refraction (CR) phenomenon is presented. The CR phenomenon occurs when light travels along one of the optical axes of a biaxial crystal (BC), leading to a bright ring of light at the focal plane of the system. We propose using the connection between the intensity pattern of the CR ring and the state of polarization (SOP) of the incident beam as a new tool for polarization metrology. In order to implement a complete polarimeter, the instrument is designed with a beam splitter and two BCs, one BC for each sub-beam. In the second sub-beam, a retarder is introduced before the BC, allowing us to measure the ellipticity content of the input SOP. The CR-based polarimeter presents several appealing features compared to standard polarimeters. To name some of them, CR polarimeters retrieve the SOP of an input beam with a single snapshot measurement, allow for substantially enhancing the data redundancy without increasing measuring time, and avoid instrumental errors related to rotating elements or active polarization devices. This work shows the instrument design, in particular the parameters of the set-up have been optimized in order to reduce the amplification of noise. Then, the experimental implementation of the instrument is detailed, including the experimental calibration of the system. Finally, the implemented polarimeter is experimentally tested by measuring different SOPs, including fully and partially polarized light.

  4. Capturing Snapshots of APE1 Processing DNA Damage

    PubMed Central

    Freudenthal, Bret D.; Beard, William A.; Cuneo, Matthew J.; Dyrkheeva, Nadezhda S.; Wilson, Samuel H.

    2015-01-01

    DNA apurinic-apyrimidinic (AP) sites are prevalent non-coding threats to genomic stability and are processed by AP endonuclease 1 (APE1). APE1 incises the AP-site phosphodiester backbone, generating a DNA repair intermediate that is potentially cytotoxic. The molecular events of the incision reaction remain elusive due in part to limited structural information. We report multiple high-resolution human APE1:DNA structures that divulge novel features of the APE1 reaction, including the metal binding site, nucleophile, and arginine clamps that mediate product release. We also report APE1:DNA structures with a T:G mismatch 5′ to the AP-site, representing a clustered lesion occurring in methylated CpG dinucleotides. These reveal that APE1 molds the T:G mismatch into a unique Watson-Crick like geometry that distorts the active site reducing incision. These snapshots provide mechanistic clarity for APE1, while affording a rational framework to manipulate biological responses to DNA damage. PMID:26458045

  5. Capturing snapshots of APE1 processing DNA damage

    DOE PAGES

    Freudenthal, Bret D.; Beard, William A.; Cuneo, Matthew J.; ...

    2015-10-12

    DNA apurinic-apyrimidinic (AP) sites are prevalent noncoding threats to genomic stability and are processed by AP endonuclease 1 (APE1). APE1 incises the AP-site phosphodiester backbone, generating a DNA-repair intermediate that is potentially cytotoxic. The molecular events of the incision reaction remain elusive, owing in part to limited structural information. Here we report multiple high-resolution human APE1-DNA structures that divulge new features of the APE1 reaction, including the metal-binding site, the nucleophile and the arginine clamps that mediate product release. We also report APE1-DNA structures with a T-G mismatch 5' to the AP site, representing a clustered lesion occurring in methylatedmore » CpG dinucleotides. Moreover, these structures reveal that APE1 molds the T-G mismatch into a unique Watson-Crick-like geometry that distorts the active site, thus reducing incision. Finally, these snapshots provide mechanistic clarity for APE1 while affording a rational framework to manipulate biological responses to DNA damage.« less

  6. Single-snapshot DOA estimation by using Compressed Sensing

    NASA Astrophysics Data System (ADS)

    Fortunati, Stefano; Grasso, Raffaele; Gini, Fulvio; Greco, Maria S.; LePage, Kevin

    2014-12-01

    This paper deals with the problem of estimating the directions of arrival (DOA) of multiple source signals from a single observation vector of an array data. In particular, four estimation algorithms based on the theory of compressed sensing (CS), i.e., the classical ℓ 1 minimization (or Least Absolute Shrinkage and Selection Operator, LASSO), the fast smooth ℓ 0 minimization, and the Sparse Iterative Covariance-Based Estimator, SPICE and the Iterative Adaptive Approach for Amplitude and Phase Estimation, IAA-APES algorithms, are analyzed, and their statistical properties are investigated and compared with the classical Fourier beamformer (FB) in different simulated scenarios. We show that unlike the classical FB, a CS-based beamformer (CSB) has some desirable properties typical of the adaptive algorithms (e.g., Capon and MUSIC) even in the single snapshot case. Particular attention is devoted to the super-resolution property. Theoretical arguments and simulation analysis provide evidence that a CS-based beamformer can achieve resolution beyond the classical Rayleigh limit. Finally, the theoretical findings are validated by processing a real sonar dataset.

  7. The tenebrionidae of california: a time sensitive snapshot assessment.

    PubMed

    Aalbu, Rolf L; Smith, Aaron D

    2014-01-01

    DUE TO A DIVERSITY OF HABITATS AND ITS GEOLOGIC HISTORY, THE US STATE OF CALIFORNIA HOSTS A SPECTACULAR ASSEMBLAGE OF DARKLING BEETLE SPECIES (COLEOPTERA: Tenebrionidae). In addition to being part of the California Floristic Province, one of 34 global biodiversity hotspots identified by Conservation International, California also has additional areas which are parts of the Great Basin, Mojave, and Sonoran deserts. California is divided into nine floristic regions. Each region is assessed in terms of faunal composition and endemism. A "snapshot" of our present knowledge of the Tenebrionidae indicates that 447 currently recognized species, representing 108 genera, occur in California of which one hundred and ninety are endemic. California is compared to other nearby regions in diversity and endemism. An analysis of currently valid species vs a more realistic species account based on unpublished records of likely synonyms and known species yet to be described in the scientific literature is presented. The California Floristic Region, rather than other more arid parts of California, has the highest number of total and endemic species. Because of their high diversity and endemism, tenebrionids could potentially provide a valuable tool for monitoring the environment for conservation purposes.

  8. The Snapshot A-Star SurveY (SASSY)

    NASA Astrophysics Data System (ADS)

    Garani, Jasmine; Nielsen, Eric L.; Marchis, Franck; Liu, Michael C.; Macintosh, Bruce; Rajan, Abhijith; De Rosa, Robert J.; Wang, Jason; Esposito, Thomas; Best, William M. J.; Bowler, Brendan P.; Dupuy, Trent J.; Ruffio, Jean-Baptise

    2017-01-01

    We present the Snapshot A-Star SurveY (SASSY), an adaptive optics survey conducted using NIRC2 on the Keck II telescope to search for young, self-luminious planets and brown dwarfs (M > 5MJup) around high mass stars (M > 1.5 M⊙). We describe a custom data-reduction pipeline developed for the coronagraphic observations of our 200 target stars. Our data analysis method includes basic near infrared data processing (flat-field correction, bad pixel removal, distortion correction) as well as performing PSF subtraction through a Reference Differential Imaging algorithm based on a library of PSFs derived from the observations using the pyKLIP routine. We present early results from the survey including planet and brown dwarf candidates and the status of ongoing follow-up observations. Utilizing the high contrast of Keck NIRC2 coronagraphic observations, SASSY reaches sensitivity to brown dwarfs and planetary mass companions at separations between 0.6'' and 4''. With over 200 stars observed we are tripling the number of high-mass stars imaged at these contrasts and sensitivities compared to previous surveys. This work was supported by the NSF REU program at the SETI Institute and NASA grant NNX14AJ80G.

  9. SHUCS: the Snapshot Hubble U-band Cluster Survey

    NASA Astrophysics Data System (ADS)

    Konstantopoulos, Iraklis; SHUCS Collaboration

    2012-01-01

    Star clusters represent a step in the star formation hierarchy above individual stars. As such, they maintain a link to the overall star formation in any galaxy, while their brightness turns them into beacons of star formation in systems out to 100 Mpc. The study of extra-galactic star clusters and their populations has undergone a revival since the launch of HST. However, their use as direct tracers of star formation depends on understanding fundamental laws that regulate the fraction of stars that form in clusters, as well as those that govern the destruction of star clusters. The Snapshot Hubble U-band Cluster Survey (SHUCS) is designed to take a few steps in that direction. By completing the UBVI baseline for galaxies with existing archival BVI coverage, we will derive the ages, masses and luminosities of thousands of clusters in 22 galaxies. This way we will be able to rule out theories and empirical scenarios regarding the formation and destruction of star clusters, and the role of environment in these processes. This talk will present a description of the survey and its many goals, and go through some first results.

  10. Long QT syndrome mutation detection by SNaPshot technique.

    PubMed

    Edelmann, Jeanett; Schumann, Stefanie; Nastainczyk, Marina; Husser-Bollmann, Daniela; Lessig, Rüdiger

    2012-11-01

    Long QT syndrome (LQTS) is a cardiac disorder with an abnormality of cardiac rhythm associated with sudden death especially in younger, apparently healthy individuals. If there is no clear cause of death detectable during comprehensive coroner's inquest (autopsy-negative cases), you have to consider LQTS and other heritable arrhythmia syndromes. A molecular genetic screening regarding mutations in associated genes can help to ensure the cause of death and to protect affected family members. Genetic testing of LQTS, currently performed mainly by sequencing, is still very expensive and time consuming. With this study we present a rapid and reasonable method for the simultaneously screening of some of the most common mutations associated with LQTS, focused on the KCNQ1 and KCNH2 genes. With the method of SNaPshot minisequencing, a total of 58 mutations were analyzed in four multiplex assays which were successfully established and optimized. The comparison with samples previously analyzed by direct sequencing showed concordance. Furthermore, autopsy-negative cases were tested but no mutations could be observed in any of the specimen. The presented method is well suitable for LQTS mutation screening. An enhancement to further mutations and population-based investigations regarding mutation frequencies should be the aim of prospective studies.

  11. Optical system design of the snapshot imaging spectrometerusing image replication based on Wollaston prism

    NASA Astrophysics Data System (ADS)

    Pei, Lin-lin; Min, Huang; Lv, Qun-bo; Wang, Jian-wei; Li, Wei-yan

    2015-01-01

    Imaging spectral is a novel detection approach which simultaneously acquires two-dimensional visual picture and one-dimensional spectral information.The imaging spectrometer not only provides abundant data for aeronautics and astronautics remote sensing, but also offers promising applications on biomedical imaging, conservation and identification of art works,surveillance of food safety,prevention and control of plant diseases and elimination of pests,and so forth. In this paper, the snapshot imaging spectrometer using image replication based on Wollaston prisms is designed. This system includes the telescope objective, the collimator lens, the wave plates, Wollaston prisms, and the imaging lens.The imaging spectrometer system based on multi-configuration can obtain a high diffraction efficiency. Every configuration provide a kind of wave. The 16 configurations are in one mechanical structure. The system's MTF at 56 line pairs is better than 0.75. The RMS of the spots are all in one pixel.The imaging spectrometer can obtain perfect data.

  12. Snapshots of enzymatic Baeyer-Villiger catalysis: oxygen activation and intermediate stabilization.

    PubMed

    Orru, Roberto; Dudek, Hanna M; Martinoli, Christian; Torres Pazmiño, Daniel E; Royant, Antoine; Weik, Martin; Fraaije, Marco W; Mattevi, Andrea

    2011-08-19

    Baeyer-Villiger monooxygenases catalyze the oxidation of carbonylic substrates to ester or lactone products using NADPH as electron donor and molecular oxygen as oxidative reactant. Using protein engineering, kinetics, microspectrophotometry, crystallography, and intermediate analogs, we have captured several snapshots along the catalytic cycle which highlight key features in enzyme catalysis. After acting as electron donor, the enzyme-bound NADP(H) forms an H-bond with the flavin cofactor. This interaction is critical for stabilizing the oxygen-activating flavin-peroxide intermediate that results from the reaction of the reduced cofactor with oxygen. An essential active-site arginine acts as anchoring element for proper binding of the ketone substrate. Its positively charged guanidinium group can enhance the propensity of the substrate to undergo a nucleophilic attack by the flavin-peroxide intermediate. Furthermore, the arginine side chain, together with the NADP(+) ribose group, forms the niche that hosts the negatively charged Criegee intermediate that is generated upon reaction of the substrate with the flavin-peroxide. The fascinating ability of Baeyer-Villiger monooxygenases to catalyze a complex multistep catalytic reaction originates from concerted action of this Arg-NADP(H) pair and the flavin subsequently to promote flavin reduction, oxygen activation, tetrahedral intermediate formation, and product synthesis and release. The emerging picture is that these enzymes are mainly oxygen-activating and "Criegee-stabilizing" catalysts that act on any chemically suitable substrate that can diffuse into the active site, emphasizing their potential value as toolboxes for biocatalytic applications.

  13. Water - Isotope - Map (δ 18O, δ 2H, 3H) of Austria: Applications, Extremes and Trends

    NASA Astrophysics Data System (ADS)

    Wyhlidal, Stefan; Kralik, Martin; Benischke, Ralf; Leis, Albrecht; Philippitsch, Rudolf

    2016-04-01

    The isotopic ratios of oxygen and hydrogen in water (2H/1H and 18O/16O) are important tools to characterise waters and their cycles. This starts in the atmosphere as rain or snow and continues in surface water and ends in shallow groundwater as well as in deep groundwater. Tritium formed by natural cosmic radiation in the upper atmosphere and in the last century by tests of thermonuclear bombs in the atmosphere, is characterised by its radioactive decay with a half-life of 12.32 years and is an ideal age-marker during the last 60 years. To determine the origin and mean age of waters in many projects concerning water supply, engineering and scientific projects in the last 45 years on more than 1,350 sites, more than 40,000 isotope measurements were performed in Austria. The median value of all sites of oxygen-18 is δ 18O -10.7 ‰ and for hydrogen-2 δ 2H -75 ‰. As the fractionation is mainly temperature dependent the lowest negative values are observed in winter precipitation (oxygen-18 as low as δ 18O -23 ‰) and in springs in the mountain regions (δ 18O -15.1 ‰). In contrast the highest values were observed in summer precipitation (up to δ 18O - 0.5 ‰) and in shallow lakes in the Seewinkel (up to δ 18O + 5 ‰). The isotopic ratios of the Austrian waters are also influenced by the origin of the evaporated water masses. Therefore the precipitation in the region south of the main Alpine crest (East-Tyrol, Carinthia and South-East Styria) is approximately 1 ‰ higher in δ 18O-values than sites at the same altitude in the northern part. This is most probably caused by the stronger influence of precipitation from the mediterranean area. The median value of all 1,120 sampling sites of decay corrected (2015) tritium measurements is 6.2 tritium units (TU). This is somewhat smaller than the median value of all precipitation stations with 7.2 TU. This can be explained by the fact that in most cases in groundwater the median value has been reduced by decay

  14. Hydrogen isotopic analysis with a chromium-packed reactor of organic compounds of relevance to ecological, archaeological, and forensic applications.

    PubMed

    Reynard, Linda M; Tuross, Noreen

    2016-08-30

    The δ(2) H values of some nitrogen-containing organic compounds measured by High-Temperature Conversion (HTC) with a glassy carbon reactor have been shown to be inaccurate. A probable explanation for these analytical inaccuracies is the formation of HCN, allowing some hydrogen atoms to escape isotope ratio measurement. We assess this isotopic effect in sample types commonly used for (paleo)ecological, environmental, archaeological, and forensic investigations. The δ(2) HVSMOW-SLAP values and mass fraction H using a factory-recommended glassy carbon HTC reactor packing were compared with those obtained from using two Cr-containing reactor packings for a variety of N-containing substances, including amino acids, collagen, hair, and silk. δ(2) HVSMOW-SLAP values and mass fraction H differed by reactor packing for most, but not all, N-containing samples. The δ(2) HVSMOW-SLAP difference was 10-11 ‰ for modern collagen and 12-14 ‰ for hair, demonstrating that reactor configuration is important for these proteins, and that the use of a chromium-packed reactor may be desirable. In contrast, Bombyx mori cocoon (silk) δ(2) HVSMOW-SLAP values did not differ with reactor type. In general, δ(2) HVSMOW-SLAP and mass fraction H differences by reactor packing increased with mass fraction nitrogen in the sample. With the Cr-packed reactor hydrogen mass fractions were at theoretically expected values, while the glassy carbon reactor produced lower yields of hydrogen. The protein and amino acid δ(2) HVSMOW-SLAP values measured by factory-recommended online HTC methods differ from those from Cr-containing reactor packing. The magnitude of the differences is variable with sample type; the molecular structure and diagenetic history of each sample may be important. Careful attention to this effect is therefore recommended for the δ(2) H measurement for all nitrogen-containing analytes. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  15. Application of isotopic tracers as a tool for understanding hydrodynamic behavior of the highly exploited Diass aquifer system (Senegal)

    NASA Astrophysics Data System (ADS)

    Madioune, Diakher Hélène; Faye, Serigne; Orban, Philippe; Brouyère, Serge; Dassargues, Alain; Mudry, Jacques; Stumpp, Christine; Maloszewski, Piotr

    2014-04-01

    The Diass horst aquifer system located 50 km east of Dakar (Senegal) is exploited in two main aquifers covered by a sandy superficial aquifer: the confined/unconfined Palaeocene karstic limestone and the confined Maastrichtian sandstone aquifer underneath. This system has experienced intensive groundwater abstraction during the last 50 years to supply increasing water demand, agricultural and industrial needs. The high abstraction rate from 1989 to 2009 (about 109,000 m3/d) has caused a continuous groundwater level decline (up to 30 m), a modification of the groundwater flow and salinization in parts of the aquifers. The objective of the study is to improve our understanding of the system functioning with regards to high pumping, identify the geochemical reactions that take place in the system, infer origin and timing of recharge by using mainly stable (δ18O, δ2H, 13C) and radioactive (3H and 14C) isotopes. Water types defined in the Piper diagram vary in order of abundance from Ca-HCO3 (65%), Ca/Na-Cl (20%), Na-HCO3 (3%) and Na-Cl (12%). Values of δ18O and δ2H for the superficial aquifer range between -5.8 and -4.2‰ and between -42 and -31‰, respectively. For the Palaeocene aquifer they range from -5.8 to -5.0‰ and from -38 to -31‰, respectively; values in the Maastrichtian aquifer are between -5.9 and -4.3‰ for δ18O and -38 to -26‰ for δ2H. Plotted against the conventional δ18O vs δ2H diagram, data from the upper aquifer exhibit a dispersed distribution with respect to isotopic fractionation while those of the Palaeocene and Maastrichtian aquifers are aligned parallel and slightly below/or on the Global Meteoric Water Line (GMWL) evidencing ancient waters which had evaporated during infiltration. The low tritium (generally <0.7 TU) and 14C (0.7-57.2 pmc) contents indicate predominance of older water being recharged during the Pleistocene and Holocene periods. However, few boreholes which exhibit high tritium (1.2-4.3 TU) and 14C (65.7-70.8 pmc

  16. Compound-specific stable isotope records of precipitation isotopes and paleotopographic evolution: Patterns of Cenozoic change in the Western U.S.

    NASA Astrophysics Data System (ADS)

    Hren, M. T.

    2014-12-01

    The topography of an orogen reflects the complex interplay between processes that occur at depth in the crust and processes such as erosion and weathering that shape the surface landscape. Reconstructions of paleotopography are critical for evaluating geodynamic models and separating effects of climatic and tectonic change in terrestrial records. Stable isotope paleoaltimetry has proved to be an important tool for understanding changes in topography through time, however this approach is complicated by factors such as mixing of moisture sources, uncertainty over how uplift impacts air mass transport and resultant isotope hydrology, and debate over what some proxies actually record. Hydrogen isotopes of organic molecules provide a means of reconstructing isotopes of ambient water, but these data are also impacted by factors that affect biological processes and stomatal regulation. Despite the myriad factors that can impact isotope fractionation in plant waxes, a growing body of data show these molecules to be an important record of precipitation isotopes when coupled with data that relates to ecosystem type. This study will examine the distribution of hydrogen isotopes of higher plant waxes across the western U.S. at key intervals of the Cenozoic to provide a snapshot of long-wavelength changes to topography and moisture sources from the Eocene to recent. These data demonstrate the utility of biomarker isotopes as a paleohydrologic/paleotopographic proxy and point to long-standing high topography over much of western U.S. throughout the Cenozoic.

  17. Application of isotope-dilution laser ablation ICP-MS for direct determination of Pu concentrations in soils at pg g(-1) levels.

    PubMed

    Boulyga, Sergei F; Tibi, Markus; Heumann, Klaus G

    2004-01-01

    The methods available for determination of environmental contamination by plutonium at ultra-trace levels require labor-consuming sample preparation including matrix removal and plutonium extraction in both nuclear spectroscopy and mass spectrometry. In this work, laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was applied for direct analysis of Pu in soil and sediment samples. Application of a LINA-Spark-Atomizer system (a modified laser ablation system providing high ablation rates) coupled with a sector-field ICP-MS resulted in detection limits as low as 3x10(-13) g g(-1) for Pu isotopes in soil samples containing uranium at a concentration of a few microg g(-1). The isotope dilution (ID) technique was used for quantification, which compensated for matrix effects in LA-ICP-MS. Interferences by UH+ and PbO2+ ions and by the peak tail of 238U+ ions were reduced or separated by use of dry plasma conditions and a mass resolution of 4000, respectively. No other effects affecting measurement accuracy, except sample inhomogeneity, were revealed. Comparison of results obtained for three contaminated soil samples by use of alpha-spectrometry, ICP-MS with sample decomposition, and LA-ICP-IDMS showed, in general, satisfactory agreement of the different methods. The specific activity of (239+240)Pu (9.8 +/- 3.0 mBq g(-1)) calculated from LA-ICP-IDMS analysis of SRM NIST 4357 coincided well with the certified value of 10.4 +/- 0.2 mBq g(-1). However, the precision of LA-ICP-MS for determination of plutonium in inhomogeneous samples, i.e. if "hot" particles are present, is limited. As far as we are aware this paper reports the lowest detection limits and element concentrations yet measured in direct LA-ICP-MS analysis of environmental samples.

  18. Application of stable isotopic techniques in the prevention of degenerative diseases like obesity and NIDDM in developing societies.

    PubMed

    Shetty, Prakash; Iyengar, Venkatesh; Sawaya, Ana; Diaz, Erik; Ma, Guansheng; Hernandez-Triana, Manuel; Yajnik, Chittaranjan; Forrester, Terrence; Valencia, Mauro; Rush, Elaine; Adeyemo, Adebowale; Jahoor, Farook; Roberts, Susan

    2002-09-01

    Economic development in developing societies characterized by industrialization, urbanization, and globalization has seen the emergence of an epidemic of diet- and life-style-related chronic degenerative diseases. A research project was initiated under the aegis of the International Atomic Energy Agency (IAEA), Vienna, Austria under its Coordinated Research Programme (CRP) to promote the use of stable isotopic techniques to document the extent of the problem and to understand the determinants of this epidemic. The principal objectives of this CRP involving countries both in the North and the South are to define the magnitude of the problem of obesity and non-insulin dependent diabetes mellitus (NIDDM) in developing countries, to identify the vulnerable groups at increased risk, and to attempt to describe the metabolic and physiological mechanisms underlying this phenomenon. These comparative international studies of obesity and NIDDM are looking at the effects of childhood malnutrition (Brazil) and socioeconomic differentials (Mexico) on adult risk factors; the composition of the daily diet on obesity (Chile); levels of patterns of physical activity of older adults (China) as well as their influence on weight gain and obesity (Cuba, Nigeria); the impact of body composition and energy expenditure on the evolution frank diabetes from impaired glucose tolerance (Jamaica), and of body compositional changes and the role of inflammatory cytokines on impaired glucose tolerance (India). The last study conducted in New Zealand was aimed at comparing the energy expenditures of Maori (Pacific Island) with New Zealanders of European descent.

  19. On the application of contemporary bulk sediment organic carbon isotope and geochemical datasets for Holocene sea-level reconstruction in NW Europe

    NASA Astrophysics Data System (ADS)

    Wilson, Graham P.

    2017-10-01

    Bulk organic stable carbon isotope (δ13C) and element geochemistry (total organic carbon (TOC) and organic carbon to total nitrogen (C/N)) analysis is a developing technique in Holocene relative sea-level (RSL) research. The uptake of this technique in Northern Europe is limited compared to North America, where the common existence of coastal marshes with isotopically distinctive C3 and C4 vegetation associated with well-defined inundation tolerance permits the reconstruction of RSL in the sediment record. In Northern Europe, the reduced range in δ13C values between organic matter sources in C3 estuaries can make the identification of elevation-dependent environments in the Holocene sediment record challenging and this is compounded by the potential for post-depositional alteration in bulk δ13C values. The use of contemporary regional δ13C, C/N and TOC datasets representing the range of physiographic conditions commonly encountered in coastal wetland sediment sequences opens up the potential of using absolute values of sediment geochemistry to infer depositional environments and associated reference water levels. In this paper, the application of contemporary bulk organic δ13C, C/N and TOC to reconstruct Holocene RSL is further explored. An extended contemporary regional geochemical dataset of published δ13C, C/N and TOC observations (n = 142) from tidal-dominated C3 wetland deposits (representing tidal flat, saltmarsh, reedswamp and fen carr environments) in temperate NW Europe is compiled, and procedures implemented to correct for the 13C Suess effect on contemporary δ13C are detailed. Partitioning around medoids analysis identifies two distinctive geochemical groups in the NW European dataset, with tidal flat/saltmarsh and reedswamp/fen carr environments exhibiting characteristically different sediment δ13C, C/N and TOC values. A logistic regression model is developed from the NW European dataset in order to objectively identify in the sediment record

  20. Stable isotope labeling methods for DNA.

    PubMed

    Nelissen, Frank H T; Tessari, Marco; Wijmenga, Sybren S; Heus, Hans A

    2016-08-01

    NMR is a powerful method for studying proteins and nucleic acids in solution. The study of nucleic acids by NMR is far more challenging than for proteins, which is mainly due to the limited number of building blocks and unfavorable spectral properties. For NMR studies of DNA molecules, (site specific) isotope enrichment is required to facilitate specific NMR experiments and applications. Here, we provide a comprehensive review of isotope-labeling strategies for obtaining stable isotope labeled DNA as well as specifically stable isotope labeled building blocks required for enzymatic DNA synthesis. Copyright © 2016 Elsevier B.V. All rights reserved.