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Sample records for analytical tem comparisons

  1. A comparison of TEM data from different near-source systems

    NASA Astrophysics Data System (ADS)

    Zhou, Nannan; Xue, Guoqiang; Chen, Weiying; Cui, Jiangwei; Chen, Kang

    2017-06-01

    Loop-source transient electromagnetic (TEM) is one of the most popular near-source TEM systems with wide applications, such as the traditional approach of prospecting metalliferous and hydrogeological targets in the subsurface. Recent efforts have been focused on the implementation of short-offset grounded-wire TEM (SOTEM), which is a newly proposed and more helpful technique for performing near-source TEM surveys. However, configurations for applying near-source TEM are complicated and have not been well investigated and tested; therefore no applicable principles can be followed and recommended for optimizing near-source TEM configuration for anomaly detection. To resolve such limitations, this study conducts a comparison of the vertical magnetic field or the electric field generated from various near-source TEM systems regarding the characteristics of their response distribution, investigation depth, as well as sensitivity to geo-electric structure, through both forward modeling and a field survey in China. It is concluded that the electric field from SOTEM has a better detection capability to resistive anomaly and higher sensitivity to the resistivity of anomaly, while the vertical magnetic fields from SOTEM and loop TEM have better detection capability to conductive anomaly and higher sensitivity to the thickness of an anomaly. From the view of detection depth, the SOTEM system performs better than the loop-TEM system, and the electric field demonstrates an even larger detection depth than the vertical magnetic field in the same SOTEM survey for commonly used parameters.

  2. Analytical study of raw Swarna Makshika (Chalcopyrite) and its Bhasma through TEM and EDAX

    PubMed Central

    Mohapatra, Sudhaldev; Jha, Chandra Bhushan

    2013-01-01

    Ayurveda, the Indian System of Medicine deals with a number of metals and minerals. Swarna Makshika (SM), a chalcopyrite one such minerals has iron (Fe), copper (Cu), and sulphur (S) as major ingredients along with other trace elements of therapeutic importance. Studies related with characterization of SM are very few. In the current study SM and SM Bhasma were analysed through Transmission Electron Microscope (TEM) and Energy Dispersive X-Ray Analysis (EDAX). Analysis reveals the presence of iron, copper, and sulphur in SM. In addition to these elements, SM Bhasma found to contain Potassium, Magnesium, Aluminum, and Silicon in trace amount. TEM study reveals that, grain size of the SM (5-10 microns) is significantly reduced in SM Bhasma to 50-200 nm. PMID:24250132

  3. Analytical study of raw Swarna Makshika (Chalcopyrite) and its Bhasma through TEM and EDAX.

    PubMed

    Mohapatra, Sudhaldev; Jha, Chandra Bhushan

    2013-04-01

    Ayurveda, the Indian System of Medicine deals with a number of metals and minerals. Swarna Makshika (SM), a chalcopyrite one such minerals has iron (Fe), copper (Cu), and sulphur (S) as major ingredients along with other trace elements of therapeutic importance. Studies related with characterization of SM are very few. In the current study SM and SM Bhasma were analysed through Transmission Electron Microscope (TEM) and Energy Dispersive X-Ray Analysis (EDAX). Analysis reveals the presence of iron, copper, and sulphur in SM. In addition to these elements, SM Bhasma found to contain Potassium, Magnesium, Aluminum, and Silicon in trace amount. TEM study reveals that, grain size of the SM (5-10 microns) is significantly reduced in SM Bhasma to 50-200 nm.

  4. CryoTEM as an Advanced Analytical Tool for Materials Chemists.

    PubMed

    Patterson, Joseph P; Xu, Yifei; Moradi, Mohammad-Amin; Sommerdijk, Nico A J M; Friedrich, Heiner

    2017-07-18

    Morphology plays an essential role in chemistry through the segregation of atoms and/or molecules into different phases, delineated by interfaces. This is a general process in materials synthesis and exploited in many fields including colloid chemistry, heterogeneous catalysis, and functional molecular systems. To rationally design complex materials, we must understand and control morphology evolution. Toward this goal, we utilize cryogenic transmission electron microscopy (cryoTEM), which can track the structural evolution of materials in solution with nanometer spatial resolution and a temporal resolution of <1 s. In this Account, we review examples of our own research where direct observations by cryoTEM have been essential to understanding morphology evolution in macromolecular self-assembly, inorganic nucleation and growth, and the cooperative evolution of hybrid materials. These three different research areas are at the heart of our approach to materials chemistry where we take inspiration from the myriad examples of complex materials in Nature. Biological materials are formed using a limited number of chemical components and under ambient conditions, and their formation pathways were refined during biological evolution by enormous trial and error approaches to self-organization and biomineralization. By combining the information on what is possible in nature and by focusing on a limited number of chemical components, we aim to provide an essential insight into the role of structure evolution in materials synthesis. Bone, for example, is a hierarchical and hybrid material which is lightweight, yet strong and hard. It is formed by the hierarchical self-assembly of collagen into a macromolecular template with nano- and microscale structure. This template then directs the nucleation and growth of oriented, nanoscale calcium phosphate crystals to form the composite material. Fundamental insight into controlling these structuring processes will eventually allow us

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  6. The function and benefits of a multifunctional heating holder developed for use with conventional high resolution analytical TEMs

    NASA Astrophysics Data System (ADS)

    Kamino, T.

    2008-08-01

    Specimen heating holder consisting of a gas injector and two sets of heating element has been developed for use with conventional high resolution analytical TEMs. One of the heating elements is used for specimen heating and the other for metal deposition. Both heating elements are made of fine wire of tungsten. The specimen holder allows high resolution in-situ TEM observation of a process of gas-solid reaction followed by a metal deposition on the reactant product. The microscope used in the study was a standard TEM equipped with EDX detector and TV camera system. Thanks to the high speed pumping system and well designed column, the pressure of the electron gun area was kept at 5x10-5Pa or lower for more than 5 hours while the specimen chamber was gas injected to the pressure of 10-1Pa. Oxidation of Al to synthesize A12O3 carrier, deposition of AuPd catalyst on the Al2O3 carrier and behaviour of the deposited AuPd nano-particles at high temperatures in the air injected environment were successfully observed at atomic resolution.

  7. Optimal sample preparation to characterize corrosion in historical photographs with analytical TEM.

    PubMed

    Grieten, Eva; Caen, Joost; Schryvers, Dominique

    2014-10-01

    An alternative focused ion beam preparation method is used for sampling historical photographs containing metallic nanoparticles in a polymer matrix. We use the preparation steps of classical ultra-microtomy with an alternative final sectioning with a focused ion beam. Transmission electron microscopy techniques show that the lamella has a uniform thickness, which is an important factor for analytical transmission electron microscopy. Furthermore, the method maintains the spatial distribution of nanoparticles in the soft matrix. The results are compared with traditional preparation techniques such as ultra-microtomy and classical focused ion beam milling.

  8. Comparison of ion milling techniques for cross-sectional TEM of semiconductors

    NASA Astrophysics Data System (ADS)

    Luck, J. T.; Boggs, C. W.; Pennycook, S. J.

    1985-03-01

    The use of cross-sectional Transmission Electron Microscopy (TEM) has become invaluable for the characterization of the near-surface regions of semiconductors following ion-implantation and/or transient thermal processing. A fast and reliable technique is required which produces a large thin region while preserving with the original sample surface. New analytical techniques, particularly the direct imaging of dopant distributions, also require good thickness uniformity. Two methods of ion milling are commonly used, and are compared. The older method involves milling with a single gun from each side in turn, whereas a newer method uses two guns to mill from both sides simultaneously.

  9. The Smallest Lunar Grains: Analytical TEM Characterization of the Sub-micron Size Fraction of a Mare Soil

    NASA Technical Reports Server (NTRS)

    Thompson, M.; Christoffersen, R.

    2010-01-01

    The chemical composition, mineralogical type, and morphology of lunar regolith grains changes considerably with decreasing size, and below the approx.25 m size range the correlation between these parameters and remotely-sensed lunar surface properties connected to space weathering increases significantly. Although trends for these parameters across grain size intervals greater than 20 m are now well established, the 0 to 20 m size interval remains relatively un-subdivided with respect to variations in grain modal composition, chemistry and microstructure. Of particular interest in this size range are grains in the approximate < 1 m diameter class, whose fundamental properties are now the focus of lunar research pertaining to electrostatic grain transport, dusty plasmas, and lunar dust effects on crew health and exploration systems. In this study we have used analytical transmission electron microscopy (TEM) to characterize the mineralogy, microstructure and major element composition of grains below the 1 m size threshold in lunar soil 10084.

  10. Practical Aspects of Electrochemical Corrosion Measurements During In Situ Analytical Transmission Electron Microscopy (TEM) of Austenitic Stainless Steel in Aqueous Media.

    PubMed

    Schilling, Sibylle; Janssen, Arne; Zaluzec, Nestor J; Burke, M Grace

    2017-08-01

    The capability to perform liquid in situ transmission electron microscopy (TEM) experiments provides an unprecedented opportunity to examine the real-time processes of physical and chemical/electrochemical reactions during the interaction between metal surfaces and liquid environments. This work describes the requisite steps to make the technique fully analytical, from sample preparation, through modifications of the electrodes, characterization of electrolytes, and finally to electrochemical corrosion experiments comparing in situ TEM to conventional bulk cell and microcell configurations.

  11. Comparison Between Eight- and Sixteen-Channel TEM Transceive Arrays for Body Imaging at 7 Tesla

    PubMed Central

    Snyder, CJ; DelaBarre, L; Moeller, S; Tian, J; Akgun, C; Van De Moortele, P-F; Bolan, PJ; Ugurbil, K; Vaughan, JT; Metzger, GJ

    2011-01-01

    Eight- and sixteen-channel transceive stripline/TEM body arrays were compared at 7 tesla (297 MHz) both in simulation and experimentally. Despite previous demonstrations of similar arrays for use in body applications, a quantitative comparison of the two configurations has not been undertaken to date. Results were obtained on a male pelvis for assessing transmit, SNR and parallel imaging performance and to evaluate local power deposition versus transmit B1 (B1+). All measurements and simulations were conducted after performing local B1+ phase shimming in the region of the prostate. Despite the additional challenges of decoupling immediately adjacent coils, the sixteen-channel array demonstrated improved or nearly equivalent performance to the eight-channel array based on the evaluation criteria. Experimentally, transmit performance and SNR were 22% higher for the sixteen-channel array while significantly increased reduction factors were achievable in the left-right direction for parallel imaging. Finite-difference time-domain simulations demonstrated similar results with respect to transmit and parallel imaging performance, however a higher transmit efficiency advantage of 33% was predicted. Simulations at both 3T and 7T verified the expected parallel imaging improvements with increasing field strength and showed that, for a specific B1+ shimming strategy employed, the sixteen-channel array exhibited lower local and global SAR for a given B1+. PMID:22102483

  12. Comparison between measured and predicted turbulence frequency spectra in ITG and TEM regimes

    NASA Astrophysics Data System (ADS)

    Citrin, J.; Arnichand, H.; Bernardo, J.; Bourdelle, C.; Garbet, X.; Jenko, F.; Hacquin, S.; Pueschel, M. J.; Sabot, R.

    2017-06-01

    The observation of distinct peaks in tokamak core reflectometry measurements—named quasi-coherent-modes (QCMs)—are identified as a signature of trapped-electron-mode (TEM) turbulence (Arnichand et al 2016 Plasma Phys. Control. Fusion 58 014037). This phenomenon is investigated with detailed linear and nonlinear gyrokinetic simulations using the Gene code. A Tore-Supra density scan is studied, which traverses through a linear (LOC) to saturated (SOC) ohmic confinement transition. The LOC and SOC phases are both simulated separately. In the LOC phase, where QCMs are observed, TEMs are robustly predicted unstable in linear studies. In the later SOC phase, where QCMs are no longer observed, ion-temperature-gradient (ITG) modes are identified. In nonlinear simulations, in the ITG (SOC) phase, a broadband spectrum is seen. In the TEM (LOC) phase, a clear emergence of a peak at the TEM frequencies is seen. This is due to reduced nonlinear frequency broadening of the underlying linear modes in the TEM regime compared with the ITG regime. A synthetic diagnostic of the nonlinearly simulated frequency spectra reproduces the features observed in the reflectometry measurements. These results support the identification of core QCMs as an experimental marker for TEM turbulence.

  13. Comparison of preparation techniques for nuclear materials for transmission electron microscopy (TEM)

    SciTech Connect

    Aitkaliyeva, Assel; Madden, James W.; Miller, Brandon D; Cole, James I; Gan, Jian

    2015-04-01

    Preparation of highly radioactive and irradiated nuclear fuels and materials for transmission electron microscopy (TEM) is conjoined with a set of unique challenges, including but not limited to personnel radiation exposure and contamination. The paper evaluates three specimen preparation techniques for preparation of irradiated materials and determines which technique yields to the most reliable characterization of radiation damage microstructure. Various specimen preparation artifacts associated with each technique are considered and ways of minimizing these artifacts are addressed.

  14. GISAXS modelling of helium-induced nano-bubble formation in tungsten and comparison with TEM

    NASA Astrophysics Data System (ADS)

    Thompson, Matt; Sakamoto, Ryuichi; Bernard, Elodie; Kirby, Nigel; Kluth, Patrick; Riley, Daniel; Corr, Cormac

    2016-05-01

    Grazing-incidence small angle x-ray scattering (GISAXS) is a powerful non-destructive technique for the measurement of nano-bubble formation in tungsten under helium plasma exposure. Here, we present a comparative study between transmission electron microscopy (TEM) and GISAXS measurements of nano-bubble formation in tungsten exposed to helium plasma in the Large Helical Device (LHD) fusion experiment. Both techniques are in excellent agreement, suggesting that nano-bubbles range from spheroidal to ellipsoidal, displaying exponential diameter distributions with mean diameters μ=0.68 ± 0.04 nm and μ=0.6 ± 0.1 nm measured by TEM and GISAXS respectively. Depth distributions were also computed, with calculated exponential depth distributions with mean depths of 8.4 ± 0.5 nm and 9.1 ± 0.4 nm for TEM and GISAXS. In GISAXS modelling, spheroidal particles were fitted with an aspect ratio ε=0.7 ± 0.1. The GISAXS model used is described in detail.

  15. High-resolution and analytical TEM investigation of metastable-tetragonal phase stabilization in undoped nanocrystalline zirconia.

    PubMed

    Oleshko, Vladimir P; Howe, James M; Shukla, Satyajit; Seal, Sudipta

    2004-09-01

    Submicron and nano-sized nanocrystalline pure zirconia (ZrO2) powders having metastable tetragonal and tetragonal-plus-monoclinic crystal structures, respectively, were synthesized using the sol-gel technique. The as-precipitated and the calcinated ZrO2 powders were analyzed for their morphology, nanocrystallite size and structures, aggregation tendency, local electronic properties, and elemental compositions by conventional and high-resolution transmission electron microscopy and field-emission analytical electron microscopy, including energy-dispersive X-ray and electron energy-loss spectroscopies. The results from this study indicate that a combination of nanocrystallite size, strain-induced grain-growth confinement, and the simultaneous presence of the monoclinic phase can lead to stabilization of the metastable tetragonal-phase in undoped ZrO2. As a result, the tetragonal phase is stabilized within ZrO2 nanocrystallites up to 100 nm in size, which is 16 times larger than the previously reported critical size of 6 nm.

  16. Streptomyces sp. TEM 33 possesses high lipolytic activity in solid-state fermentation in comparison with submerged fermentation.

    PubMed

    Cadirci, Bilge Hilal; Yasa, Ihsan; Kocyigit, Ali

    2016-01-01

    Solid-state fermentation (SSF) is a bioprocess that doesn't need an excess of free water, and it offers potential benefits for microbial cultivation for bioprocesses and product development. In comparing the antibiotic production, few detailed reports could be found with lipolytic enzyme production by Streptomycetes in SSF. Taking this knowledge into consideration, we prefer to purify Actinomycetes species as a new source for lipase production. The lipase-producing strain Streptomyces sp. TEM 33 was isolated from soil and lipase production was managed by solid-state fermentation (SSF) in comparison with submerged fermentation (SmF). Bioprocess-affecting factors like initial moisture content, incubation time, and various carbon and nitrogen additives and the other enzymes secreted into the media were optimized. Lipase activity was measured as 1.74 ± 0.0005 U/g dry substrate (gds) by the p-nitrophenylpalmitate (pNPP) method on day 6 of fermentation with 71.43% final substrate moisture content. In order to understand the metabolic priority in SSF, cellulase and xylanase activity of Streptomyces sp. TEM33 was also measured. The microorganism degrades the wheat bran to its usable form by excreting cellulases and xylanases; then it secretes the lipase that is necessary for degrading the oil in the medium.

  17. High-Resolution and Analytical TEM Investigation of Space Radiation Processing Effects in Primitive Solar System Materials and Airless Planetary Surface Environments

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

    Energetic ions present in the diverse plasma conditions in space play a significant role in the formation and modification of solid phases found in environments ranging from the interstellar medium (ISM) to the surfaces of airless bodies such as asteroids and the Moon. These effects are often referred to as space radiation processing, a term that encompasses changes induced in natural space-exposed materials that may be only structural, such as in radiation-induced amorphization, or may involve ion-induced nanoscale to microscale chemical changes, as occurs in preferential sputtering and ion-beam mixing. Ion sputtering in general may also be responsible for partial or complete erosion of space exposed materials, in some instances possibly bringing about the complete destruction of free-floating solid grains in the ISM or in circumstellar nebular dust clouds. We report here on two examples of the application of high-resolution and analytical transmission electron microscopy (TEM) to problems in space radiation processing. The first problem concerns the role of space radiation processing in controlling the overall fate of Fe sulfides as hosts for sulfur in the ISM. The second problem concerns the known, but as yet poorly quantified, role of space radiation processing in lunar space weathering.

  18. Comparison of different sample preparation techniques in TEM observation of microstructure of INCONEL alloy 783 subjected to prolonged isothermal exposure.

    PubMed

    Ma, Longzhou

    2004-01-01

    INCONEL alloy 783 was annealed and aged following the standard heat treatment procedure. One set of specimens was then isothermally exposed at 500 degrees C for 3000 h. Mechanical properties were measured at room temperature and 650 degrees C, and the results showed the prolonged exposure increased the strength and decreased elongation of alloy 783. The microstructures of as-produced and exposed material were examined using optical microscope, SEM and TEM, respectively. Three techniques, jet electro-polishing, ion milling, and focused ion beam, were employed to prepare the TEM samples to observe the variation of microstructure of alloy 783 due to isothermal exposure. TEM images of samples prepared by different methods were analyzed and compared. The results indicate that the jet electro-polishing technique allows the detail microstructure of alloy 783 subjected to different treatments to be well revealed, and thereby the TEM images can be used to explain the enhancement of strength of alloy 783 caused by isothermal exposure.

  19. Comparison of analytical error and sampling error for contaminated soil.

    PubMed

    Gustavsson, Björn; Luthbom, Karin; Lagerkvist, Anders

    2006-11-16

    Investigation of soil from contaminated sites requires several sample handling steps that, most likely, will induce uncertainties in the sample. The theory of sampling describes seven sampling errors that can be calculated, estimated or discussed in order to get an idea of the size of the sampling uncertainties. With the aim of comparing the size of the analytical error to the total sampling error, these seven errors were applied, estimated and discussed, to a case study of a contaminated site. The manageable errors were summarized, showing a range of three orders of magnitudes between the examples. The comparisons show that the quotient between the total sampling error and the analytical error is larger than 20 in most calculation examples. Exceptions were samples taken in hot spots, where some components of the total sampling error get small and the analytical error gets large in comparison. Low concentration of contaminant, small extracted sample size and large particles in the sample contribute to the extent of uncertainty.

  20. Comparison of open-source visual analytics toolkits

    NASA Astrophysics Data System (ADS)

    Harger, John R.; Crossno, Patricia J.

    2012-01-01

    We present the results of the first stage of a two-stage evaluation of open source visual analytics packages. This stage is a broad feature comparison over a range of open source toolkits. Although we had originally intended to restrict ourselves to comparing visual analytics toolkits, we quickly found that very few were available. So we expanded our study to include information visualization, graph analysis, and statistical packages. We examine three aspects of each toolkit: visualization functions, analysis capabilities, and development environments. With respect to development environments, we look at platforms, language bindings, multi-threading/parallelism, user interface frameworks, ease of installation, documentation, and whether the package is still being actively developed.

  1. Measuring solids concentration in stormwater runoff: comparison of analytical methods.

    PubMed

    Clark, Shirley E; Siu, Christina Y S

    2008-01-15

    Stormwater suspended solids typically are quantified using one of two methods: aliquot/subsample analysis (total suspended solids [TSS]) or whole-sample analysis (suspended solids concentration [SSC]). Interproject comparisons are difficult because of inconsistencies in the methods and in their application. To address this concern, the suspended solids content has been measured using both methodologies in many current projects, but the question remains about how to compare these values with historical water-quality data where the analytical methodology is unknown. This research was undertaken to determine the effect of analytical methodology on the relationship between these two methods of determination of the suspended solids concentration, including the effect of aliquot selection/collection method and of particle size distribution (PSD). The results showed that SSC was best able to represent the known sample concentration and that the results were independent of the sample's PSD. Correlations between the results and the known sample concentration could be established for TSS samples, but they were highly dependent on the sample's PSD and on the aliquot collection technique. These results emphasize the need to report not only the analytical method but also the particle size information on the solids in stormwater runoff.

  2. Benchmark Comparison of Cloud Analytics Methods Applied to Earth Observations

    NASA Technical Reports Server (NTRS)

    Lynnes, Chris; Little, Mike; Huang, Thomas; Jacob, Joseph; Yang, Phil; Kuo, Kwo-Sen

    2016-01-01

    Cloud computing has the potential to bring high performance computing capabilities to the average science researcher. However, in order to take full advantage of cloud capabilities, the science data used in the analysis must often be reorganized. This typically involves sharding the data across multiple nodes to enable relatively fine-grained parallelism. This can be either via cloud-based file systems or cloud-enabled databases such as Cassandra, Rasdaman or SciDB. Since storing an extra copy of data leads to increased cost and data management complexity, NASA is interested in determining the benefits and costs of various cloud analytics methods for real Earth Observation cases. Accordingly, NASA's Earth Science Technology Office and Earth Science Data and Information Systems project have teamed with cloud analytics practitioners to run a benchmark comparison on cloud analytics methods using the same input data and analysis algorithms. We have particularly looked at analysis algorithms that work over long time series, because these are particularly intractable for many Earth Observation datasets which typically store data with one or just a few time steps per file. This post will present side-by-side cost and performance results for several common Earth observation analysis operations.

  3. Benchmark Comparison of Cloud Analytics Methods Applied to Earth Observations

    NASA Astrophysics Data System (ADS)

    Lynnes, C.; Little, M. M.; Huang, T.; Jacob, J. C.; Yang, C. P.; Kuo, K. S.

    2016-12-01

    Cloud computing has the potential to bring high performance computing capabilities to the average science researcher. However, in order to take full advantage of cloud capabilities, the science data used in the analysis must often be reorganized. This typically involves sharding the data across multiple nodes to enable relatively fine-grained parallelism. This can be either via cloud-based filesystems or cloud-enabled databases such as Cassandra, Rasdaman or SciDB. Since storing an extra copy of data leads to increased cost and data management complexity, NASA is interested in determining the benefits and costs of various cloud analytics methods for real Earth Observation cases. Accordingly, NASA's Earth Science Technology Office and Earth Science Data and Information Systems project have teamed with cloud analytics practitioners to run a benchmark comparison on cloud analytics methods using the same input data and analysis algorithms. We have particularly looked at analysis algorithms that work over long time series, because these are particularly intractable for many Earth Observation datasets which typically store data with one or just a few time steps per file. This post will present side-by-side cost and performance results for several common Earth observation analysis operations.

  4. Comparison between analytical and numerical solution of mathematical drying model

    NASA Astrophysics Data System (ADS)

    Shahari, N.; Rasmani, K.; Jamil, N.

    2016-02-01

    Drying is often related to the food industry as a process of shifting heat and mass inside food, which helps in preserving food. Previous research using a mass transfer equation showed that the results were mostly concerned with the comparison between the simulation model and the experimental data. In this paper, the finite difference method was used to solve a mass equation during drying using different kinds of boundary condition, which are equilibrium and convective boundary conditions. The results of these two models provide a comparison between the analytical and the numerical solution. The result shows a close match between the two solution curves. It is concluded that the two proposed models produce an accurate solution to describe the moisture distribution content during the drying process. This analysis indicates that we have confidence in the behaviour of moisture in the numerical simulation. This result demonstrated that a combined analytical and numerical approach prove that the system is behaving physically. Based on this assumption, the model of mass transfer was extended to include the temperature transfer, and the result shows a similar trend to those presented in the simpler case.

  5. Comparison of analytical methods for calculation of wind loads

    NASA Technical Reports Server (NTRS)

    Minderman, Donald J.; Schultz, Larry L.

    1989-01-01

    The following analysis is a comparison of analytical methods for calculation of wind load pressures. The analytical methods specified in ASCE Paper No. 3269, ANSI A58.1-1982, the Standard Building Code, and the Uniform Building Code were analyzed using various hurricane speeds to determine the differences in the calculated results. The winds used for the analysis ranged from 100 mph to 125 mph and applied inland from the shoreline of a large open body of water (i.e., an enormous lake or the ocean) a distance of 1500 feet or ten times the height of the building or structure considered. For a building or structure less than or equal to 250 feet in height acted upon by a wind greater than or equal to 115 mph, it was determined that the method specified in ANSI A58.1-1982 calculates a larger wind load pressure than the other methods. For a building or structure between 250 feet and 500 feet tall acted upon by a wind rangind from 100 mph to 110 mph, there is no clear choice of which method to use; for these cases, factors that must be considered are the steady-state or peak wind velocity, the geographic location, the distance from a large open body of water, and the expected design life and its risk factor.

  6. Analytical TEM characterization of modified F82H and 14YW under irradiation of simultaneous helium and neutron irradiation compared to only neutron at 500 C

    SciTech Connect

    Jung, Hee Joon; Edwards, Danny J.; Yao, Bo; Kurtz, Richard J.; Odette, G Robert; Yamamoto, Takuya; Wu, Yuan

    2014-08-30

    A RAFM steel and an ODS ferritic alloy (F82H.mod3+CW and 14YW, respectively) were irradiated as part of the JP27 irradiation experiment conducted in the High Flux Isotope Reactor to explore He effects in structural alloys. The ISHI technique is used to implant He up to 9 µm below the surface of a NiAl coated sample at He/dpa levels up to ~50. This report summarizes the current status of TEM characterization of two irradiated alloys. The He-implanted side of the RAFM alloy exhibited significant swelling due to bubble and void formation within the matrix, on pre-existing dislocations, and at interfaces within the material. The 14YW alloy exhibited significant swelling even in the absence of implanted He, primarily through large voids that formed on the ODS particles. In addition, significant radiation-induced segregation of the Cr was observed around oxide particles and on lath boundaries, and visible α' particles could be detected via elemental mapping of the matrix of the 14YW alloy.

  7. Performance Comparison of Big Data Analytics With NEXUS and Giovanni

    NASA Astrophysics Data System (ADS)

    Jacob, J. C.; Huang, T.; Lynnes, C.

    2016-12-01

    NEXUS is an emerging data-intensive analysis framework developed with a new approach for handling science data that enables large-scale data analysis. It is available through open source. We compare performance of NEXUS and Giovanni for 3 statistics algorithms applied to NASA datasets. Giovanni is a statistics web service at NASA Distributed Active Archive Centers (DAACs). NEXUS is a cloud-computing environment developed at JPL and built on Apache Solr, Cassandra, and Spark. We compute global time-averaged map, correlation map, and area-averaged time series. The first two algorithms average over time to produce a value for each pixel in a 2-D map. The third algorithm averages spatially to produce a single value for each time step. This talk is our report on benchmark comparison findings that indicate 15x speedup with NEXUS over Giovanni to compute area-averaged time series of daily precipitation rate for the Tropical Rainfall Measuring Mission (TRMM with 0.25 degree spatial resolution) for the Continental United States over 14 years (2000-2014) with 64-way parallelism and 545 tiles per granule. 16-way parallelism with 16 tiles per granule worked best with NEXUS for computing an 18-year (1998-2015) TRMM daily precipitation global time averaged map (2.5 times speedup) and 18-year global map of correlation between TRMM daily precipitation and TRMM real time daily precipitation (7x speedup). These and other benchmark results will be presented along with key lessons learned in applying the NEXUS tiling approach to big data analytics in the cloud.

  8. COMPARISON BETWEEN DISCRETE AND SEMI-CONTINUOUS LAYERED MODELS OF SUPERCONDUCTING VORTICES IN HIGH TC MATERIALS FOR TEM OBSERVATIONS.

    SciTech Connect

    BELEGGIA,M.; POZZI,G.; TONOMURA,A.

    2004-08-01

    In order to interpret Transmission Electron Microscopy observations of superconducting vortices in anisotropic or layered materials we have found the analytical solution for the Fourier transform of the electron optical phase shift for the case of a straight vortex piercing the specimen at arbitrary angle. The layered case suffered from the shortcoming that only a limited number of pancakes; up to 7, is allowed by the discrete approach followed. Seven layers, however, are scarcely representative of the real stack of pancake vortices, especially when the core pierces the specimen at large angles with respect to the specimen normal. In fact, in these conditions, the pancake discrete structure may no longer be buried in the diffraction fringes of the Fresnel image. Moreover, a small number of layers is a limiting factor when more exotic vortex structures with no straight cores are investigated. This drawback has been overcome by a semi-continuous approach, where each pancake layer is considered singularly, and the discrete structure of the other pancakes is substituted by a superconducting continuous medium that carries supercurrent only parallel to the layers, as proposed by Clem and further developed by Coffey and Phipps. The solution for the vector potential has been found by Fourier methods, connecting the general solutions in the vacuum with those in the superconducting regions. The presence of a vortex in the layer is taken into account by considering the layer as an additional superconducting region of negligible thickness. Once the vector potential is found, the electron optical phase shift can be calculated by integrating the vector potential along a straight trajectory suitably chosen in order to take correctly into account the overall geometry of the experimental set-up, including a tilt of the specimen with respect to the electron beam.

  9. A Structural Comparison of Analytical Models for University Planning.

    ERIC Educational Resources Information Center

    Weathersby, George B.; Weinstein, Milton C.

    This paper provides a conceptual framework for the evaluation of analytical planning models designed for application in institutions of higher education. In an attempt to address the most important and difficult decisions facing managers of higher education, the majority of the analytical models that have been recently developed have focused upon…

  10. Surface NMR sounding and inversion to detect groundwater in key aquifers in England: comparisons with VES TEM methods

    NASA Astrophysics Data System (ADS)

    Meju, Max A.; Denton, Paul; Fenning, Peter

    2002-05-01

    This paper describes pilot experiments to assess the potential of nuclear magnetic resonance (NMR) sounding and inversion for detecting groundwater at several sites in built-up, industrial and intensively cultivated regions in England where it is difficult to deploy large transmitter loops. The targets represent near-surface (ca. 1 m below the surface) and deep (>30 m) aquiferous (chalk, sand and gravel) deposits. The NUMIS field system was used in all the experiments and has infield processing and regularised one-dimensional (1D) inversion capabilities. All the sites were characterised by high noise levels and NMR depth soundings could only be effected using a small figure-of-eight loop for which the maximum depth of investigation was approximately 40-50 m. For comparison, conventional inductive and galvanic resistivity depth soundings were performed at these sites and the data have been inverted to yield the respective subsurface resistivity distributions. At two sites with shallow water levels, the location of the water deduced from inversion of NMR data corresponded with the water level measured in the nearby boreholes. For the site where the data quality is highest, the inverted profile of decay constants also corresponded with the known geology and the geoelectrical model. The NMR data from the other five sites are noisy and it is difficult to ascertain what aspects of the inversion models are correlatable to geoelectrical and geological data. The geoelectrical inversion results correlate with lithological and fluid content variations in the subsurface. It would appear that surface NMR (SNMR) sounding with figure-of-eight loop may be effective only when the ambient noise is less than 900 nV in the UK setting.

  11. Pyrrolizidine alkaloids in honey: comparison of analytical methods.

    PubMed

    Kempf, M; Wittig, M; Reinhard, A; von der Ohe, K; Blacquière, T; Raezke, K-P; Michel, R; Schreier, P; Beuerle, T

    2011-03-01

    Pyrrolizidine alkaloids (PAs) are a structurally diverse group of toxicologically relevant secondary plant metabolites. Currently, two analytical methods are used to determine PA content in honey. To achieve reasonably high sensitivity and selectivity, mass spectrometry detection is demanded. One method is an HPLC-ESI-MS-MS approach, the other a sum parameter method utilising HRGC-EI-MS operated in the selected ion monitoring mode (SIM). To date, no fully validated or standardised method exists to measure the PA content in honey. To establish an LC-MS method, several hundred standard pollen analysis results of raw honey were analysed. Possible PA plants were identified and typical commercially available marker PA-N-oxides (PANOs). Three distinct honey sets were analysed with both methods. Set A consisted of pure Echium honey (61-80% Echium pollen). Echium is an attractive bee plant. It is quite common in all temperate zones worldwide and is one of the major reasons for PA contamination in honey. Although only echimidine/echimidine-N-oxide were available as reference for the LC-MS target approach, the results for both analytical techniques matched very well (n = 8; PA content ranging from 311 to 520 µg kg(-1)). The second batch (B) consisted of a set of randomly picked raw honeys, mostly originating from Eupatorium spp. (0-15%), another common PA plant, usually characterised by the occurrence of lycopsamine-type PA. Again, the results showed good consistency in terms of PA-positive samples and quantification results (n = 8; ranging from 0 to 625 µg kg(-1) retronecine equivalents). The last set (C) was obtained by consciously placing beehives in areas with a high abundance of Jacobaea vulgaris (ragwort) from the Veluwe region (the Netherlands). J. vulgaris increasingly invades countrysides in Central Europe, especially areas with reduced farming or sites with natural restorations. Honey from two seasons (2007 and 2008) was sampled. While only trace amounts of

  12. Learning through Case Comparisons: A Meta-Analytic Review

    ERIC Educational Resources Information Center

    Alfieri, Louis; Nokes-Malach, Timothy J.; Schunn, Christian D.

    2013-01-01

    Over the past 20 years, there has been much research on how people learn from case comparisons. This work has implemented comparison activities in a variety of different ways across a wide range of laboratory and classroom contexts. In an effort to assess the overall effectiveness of case comparisons across this diversity of implementation and…

  13. Learning through Case Comparisons: A Meta-Analytic Review

    ERIC Educational Resources Information Center

    Alfieri, Louis; Nokes-Malach, Timothy J.; Schunn, Christian D.

    2013-01-01

    Over the past 20 years, there has been much research on how people learn from case comparisons. This work has implemented comparison activities in a variety of different ways across a wide range of laboratory and classroom contexts. In an effort to assess the overall effectiveness of case comparisons across this diversity of implementation and…

  14. TEM turbulence optimisation in stellarators

    NASA Astrophysics Data System (ADS)

    Proll, J. H. E.; Mynick, H. E.; Xanthopoulos, P.; Lazerson, S. A.; Faber, B. J.

    2016-01-01

    With the advent of neoclassically optimised stellarators, optimising stellarators for turbulent transport is an important next step. The reduction of ion-temperature-gradient-driven turbulence has been achieved via shaping of the magnetic field, and the reduction of trapped-electron mode (TEM) turbulence is addressed in the present paper. Recent analytical and numerical findings suggest TEMs are stabilised when a large fraction of trapped particles experiences favourable bounce-averaged curvature. This is the case for example in Wendelstein 7-X (Beidler et al 1990 Fusion Technol. 17 148) and other Helias-type stellarators. Using this knowledge, a proxy function was designed to estimate the TEM dynamics, allowing optimal configurations for TEM stability to be determined with the STELLOPT (Spong et al 2001 Nucl. Fusion 41 711) code without extensive turbulence simulations. A first proof-of-principle optimised equilibrium stemming from the TEM-dominated stellarator experiment HSX (Anderson et al 1995 Fusion Technol. 27 273) is presented for which a reduction of the linear growth rates is achieved over a broad range of the operational parameter space. As an important consequence of this property, the turbulent heat flux levels are reduced compared with the initial configuration.

  15. A Simple Analytic ICP Model and Comparison to Experiment

    NASA Astrophysics Data System (ADS)

    Juliano, Daniel R.; Hayden, Douglas B.; Ruzic, David N.

    1996-10-01

    An analytic model is developed for a cylindrically symmetric inductively coupled plasma system in order to find the electron temperature and density distribution. Boltzmann's equation is solved by a computer code using a 2-term spherical harmonic expansion. Analytic results are compared to experimental measurements made with a Langmuir probe. The apparatus is a magnetron system (magnetron system donated by MRC) with an RF coil or other ionization source inserted between the target and substrate. Far from the target, the resulting plasma is dominated by this ionization source, so the plasma at the magnetron target is not accounted for in the analytic model. In the model, electric and magnetic fields from the RF coil are found as a function of position and the power deposition profile is calculated. Insights gained from this model have been used to guide research efforts in ionizing the sputter flux in the magnetron.

  16. Selecting Evaluation Comparison Groups: A Cluster Analytic Approach.

    ERIC Educational Resources Information Center

    Davis, Todd Mclin; McLean, James E.

    A persistent problem in the evaluation of field-based projects is the lack of no-treatment comparison groups. Frequently, potential comparison groups are confounded by socioeconomic, racial, or other factors. Among the possible methods for dealing with this problem are various matching procedures, but they are cumbersome to use with multiple…

  17. Selecting Evaluation Comparison Groups: A Cluster Analytic Approach.

    ERIC Educational Resources Information Center

    Davis, Todd Mclin; McLean, James E.

    A persistent problem in the evaluation of field-based projects is the lack of no-treatment comparison groups. Frequently, potential comparison groups are confounded by socioeconomic, racial, or other factors. Among the possible methods for dealing with this problem are various matching procedures, but they are cumbersome to use with multiple…

  18. Wake redirection: comparison of analytical, numerical and experimental models

    NASA Astrophysics Data System (ADS)

    Wang, Jiangang; Bottasso, Carlo L.; Campagnolo, Filippo

    2016-09-01

    This paper focuses on wake redirection techniques for wind farm control. Two control strategies are investigated: yaw misalignment and cyclic pitch control. First, analytical formulas are derived for both techniques, with the goal of providing a simple physical interpretation of the behavior of the two methods. Next, more realistic results are obtained by numerical simulations performed with CFD and by experiments conducted with scaled wind turbine models operating in a boundary layer wind tunnel. Comparing the analytical, numerical and experimental models allows for a cross-validation of the results and a better understanding of the two wake redirection techniques. Results indicate that yaw misalignment is more effective than cyclic pitch control in displacing the wake laterally, although the latter may have positive effects on wake recovery.

  19. Nanofluidic ionic diodes. Comparison of analytical and numerical solutions.

    PubMed

    Vlassiouk, Ivan; Smirnov, Sergei; Siwy, Zuzanna

    2008-08-01

    Recently reported experimental and theoretical studies of nanofluidic nonlinear devices, such as bipolar and unipolar ionic diodes, have yet to answer the question about the possibility of their further miniaturization. In this Article, we theoretically investigate the effects of size reduction, applied bias, and solution ionic strength in such devices. We compare the numerical solutions of the Poisson, Nernst-Planck (PNP), and Navier-Stokes (NS) equations with their one-dimensional, analytical approximations. We demonstrate that the contribution of electroosmosis is insignificant and find analytical approximations to PNP for bipolar and unipolar diodes that are in good agreement with numerical 3D solutions. We identify the minimal dimensions for such diodes that demonstrate ion current rectification behavior and demonstrate the importance of the edge effect in very short diodes.

  20. Experimental Hypervelocity Dust Impact in Olivine: FIB/TEM Characterization of Micron-Scale Craters with Comparison to Natural and Laser-Simulated Small-Scale Impact Effects

    NASA Technical Reports Server (NTRS)

    Christoffersen, R.; Loeffler, M. J.; Rahman, Z.; Dukes, C.; IMPACT Team

    2017-01-01

    The space weathering of regoliths on airless bodies and the formation of their exospheres is driven to a large extent by hypervelocity impacts from the high relative flux of micron to sub-micron meteoroids that comprise approximately 90 percent of the solar system meteoroid population. Laboratory hypervelocity impact experiments are crucial for quantifying how these small impact events drive space weathering through target shock, melting and vaporization. Simulating these small scale impacts experimentally is challenging because the natural impactors are both very small and many have velocities above the approximately 8 kilometers-per-second limit attainable by conventional chemical/light gas accelerator technology. Electrostatic "dust" accelerators, such as the one recently developed at the Colorado Center for Lunar Dust and Atmospheric Studies (CCLDAS), allow the experimental velocity regime to be extended up to tens of kilometers-per-second. Even at these velocities the region of latent target damage created by each impact, in the form of microcraters or pits, is still only about 0.1 to 10 micrometers in size. Both field-emission analytical scanning electron microscopy (FE-SEM) and advanced field-emission scanning transmission electron microscopy (FE-STEM) are uniquely suited for characterizing the individual dust impact sites in these experiments. In this study, we have used both techniques, along with focused ion beam (FIB) sample preparation, to characterize the micrometer to nanometer scale effects created by accelerated dust impacts into olivine single crystals. To our knowledge this work presents the first TEM-scale characterization of dust impacts into a key solar system silicate mineral using the CCLDAS facility. Our overarching goal for this work is to establish a basis to compare with our previous results on natural dust-impacted lunar olivine and laser-irradiated olivine.

  1. Comparison between methods of analytical continuation for bosonic functions

    NASA Astrophysics Data System (ADS)

    Schött, J.; van Loon, E. G. C. P.; Locht, I. L. M.; Katsnelson, M. I.; Di Marco, I.

    2016-12-01

    In this paper we perform a critical assessment of different known methods for the analytical continuation of bosonic functions, namely, the maximum entropy method, the non-negative least-squares method, the non-negative Tikhonov method, the Padé approximant method, and a stochastic sampling method. Four functions of different shape are investigated, corresponding to four physically relevant scenarios. They include a simple two-pole model function; two flavors of the tight-binding model on a square lattice, i.e., a single-orbital metallic system and a two-orbital insulating system; and the Hubbard dimer. The effect of numerical noise in the input data on the analytical continuation is discussed in detail. Overall, the stochastic method by A. S. Mishchenko et al. [Phys. Rev. B 62, 6317 (2000), 10.1103/PhysRevB.62.6317] is shown to be the most reliable tool for input data whose numerical precision is not known. For high-precision input data, this approach is slightly outperformed by the Padé approximant method, which combines a good-resolution power with a good numerical stability. Although none of the methods retrieves all features in the spectra in the presence of noise, our analysis provides a useful guideline for obtaining reliable information of the spectral function in cases of practical interest.

  2. Comparison of analytical eddy current models using principal components analysis

    NASA Astrophysics Data System (ADS)

    Contant, S.; Luloff, M.; Morelli, J.; Krause, T. W.

    2017-02-01

    Monitoring the gap between the pressure tube (PT) and the calandria tube (CT) in CANDU® fuel channels is essential, as contact between the two tubes can lead to delayed hydride cracking of the pressure tube. Multifrequency transmit-receive eddy current non-destructive evaluation is used to determine this gap, as this method has different depths of penetration and variable sensitivity to noise, unlike single frequency eddy current non-destructive evaluation. An Analytical model based on the Dodd and Deeds solutions, and a second model that accounts for normal and lossy self-inductances, and a non-coaxial pickup coil, are examined for representing the response of an eddy current transmit-receive probe when considering factors that affect the gap response, such as pressure tube wall thickness and pressure tube resistivity. The multifrequency model data was analyzed using principal components analysis (PCA), a statistical method used to reduce the data set into a data set of fewer variables. The results of the PCA of the analytical models were then compared to PCA performed on a previously obtained experimental data set. The models gave similar results under variable PT wall thickness conditions, but the non-coaxial coil model, which accounts for self-inductive losses, performed significantly better than the Dodd and Deeds model under variable resistivity conditions.

  3. Smoke of cigarettes and little cigars: an analytical comparison.

    PubMed

    Hoffmann, D; Wynder, E L

    1972-12-15

    Chemical data are presented from a comparison study of the smoke of cigarettes and little cigars. The tobacco products and their mainstream smokes were analyzed for a number of toxic constituents in an effort to define "smoke inhalability." This issue has particular public health importance because the difference in the inhalability of cigar and cigarette smoke is generally assumed to account for the differences in the health risk to the individual smoker.

  4. A comparison of three classical analytical theories for the motion of artificial satellites

    NASA Technical Reports Server (NTRS)

    Gordon, R. A.; Mistreets, G. D.; Watson, J. S.

    1978-01-01

    Motivated by the heavy reliance upon the analytic orbit theory in orbit determination operations at the Goddard Space Flight Center (GSFC), a comparison study is performed for three classical analytical theories of artificial satellite motion about an oblate earth. The three analytical theories are: (1) Brouwer, (2) a modified Brouwer, i.e., Brouwer-Lyddane and Cohen, and (3) Vinti. Comparison results for each theory are produced for a number of representative satellites of current or past interest which proved amenable to analytic theory application. The uniformity of these results has significant implications for current and future mission operations and planning activities. Subsidiary topics arising from the results of this study which relate to the optimum usage of the individual theories are also discussed

  5. Comparisons between analytic and numerical calculations of GRB spectra

    NASA Astrophysics Data System (ADS)

    Dermer, Charles D.; Böttcher, Markus; Chiang, James

    2000-09-01

    Formulas of Sari, Piran, and Narayan for the spectral energy distributions of gamma-ray burst blast waves are extended to include synchrotron self-absorption and Compton scattering and, given a simple numerical integration, to apply to general radiative regimes. The expressions are compared with detailed numerical simulation results and are most accurate (within a factor of ~3) in the optical/X-ray regime during the afterglow phase. Comparison of spectral energy distributions are made for the parameters used by Wijers and Galama to fit GRB 970508. .

  6. Comparison of Experimental and Analytical Performance for Contoured Endwall Stators

    NASA Technical Reports Server (NTRS)

    Boyle, R. J.; Haas, J. E.

    1982-01-01

    Comparisons between predicted and experimental stator losses showed that the analysis was able to predict the change in stator loss when contoured endwalls with highly three dimensional passage geometry were used. The level of loss was predicted to within 75 percent of that measured. The predicted loss was due only to profile loss and boundary layer growth on the endwalls. The 25 percent difference was approximately 0.015 at design pressure ratio. The analysis was shown to predict the trend in stator flow angle, even for small stator geometries.

  7. An experimental/analytical comparison of strains in encapsulated assemblies

    SciTech Connect

    Guess, T.R.; Burchett, S.N.

    1991-11-01

    A combined experimental and analytical study of strains developed in encapsulated assemblies during casting, curing and thermal excursions is described. The experimental setup, designed to measure in situ strains, consisted of thin, closed-end, Kovar tubes that were instrumented with strain gages and thermocouples before being over-cast with a polymeric encapsulant. Four bisphenol A (three diethanolamine cured and one anhydride cured) epoxy-based materials and one urethane elastomeric material were studied. After cure of the encapsulant, tube strains were measured over the temperature range of {minus}55{degrees}C to 90{degrees}C. The thermal excursion experiments were then numerically modeled using finite element analyses and the computed strains were compared to the experimental strains. The predicted strains were over estimated (conservative) when a linear, elastic, temperature-dependent material model was assumed for the encapsulant and the stress free temperature T{sub i} was assumed to correspond to the cure temperature {Tc} of the encapsulant. Very good agreement was obtained with linear elastic calculations provided that the stress free temperature corresponded to the onset of the glassy-to-rubbery transition range of the encapsulant. Finally, excellent agreement was obtained in one of the materials (828/DEA) when a viscoelastic material model was utilized and a stress free temperature corresponding to the cure temperature was assumed. 13 refs., 20 figs., 3 tabs.

  8. Comparison of soil sampling and analytical methods for asbestos at the Sumas Mountain Asbestos Site-Working towards a toolbox for better assessment.

    PubMed

    Wroble, Julie; Frederick, Timothy; Frame, Alicia; Vallero, Daniel

    2017-01-01

    Established soil sampling methods for asbestos are inadequate to support risk assessment and risk-based decision making at Superfund sites due to difficulties in detecting asbestos at low concentrations and difficulty in extrapolating soil concentrations to air concentrations. Environmental Protection Agency (EPA)'s Office of Land and Emergency Management (OLEM) currently recommends the rigorous process of Activity Based Sampling (ABS) to characterize site exposures. The purpose of this study was to compare three soil analytical methods and two soil sampling methods to determine whether one method, or combination of methods, would yield more reliable soil asbestos data than other methods. Samples were collected using both traditional discrete ("grab") samples and incremental sampling methodology (ISM). Analyses were conducted using polarized light microscopy (PLM), transmission electron microscopy (TEM) methods or a combination of these two methods. Data show that the fluidized bed asbestos segregator (FBAS) followed by TEM analysis could detect asbestos at locations that were not detected using other analytical methods; however, this method exhibited high relative standard deviations, indicating the results may be more variable than other soil asbestos methods. The comparison of samples collected using ISM versus discrete techniques for asbestos resulted in no clear conclusions regarding preferred sampling method. However, analytical results for metals clearly showed that measured concentrations in ISM samples were less variable than discrete samples.

  9. Comparison of soil sampling and analytical methods for asbestos at the Sumas Mountain Asbestos Site—Working towards a toolbox for better assessment

    PubMed Central

    2017-01-01

    Established soil sampling methods for asbestos are inadequate to support risk assessment and risk-based decision making at Superfund sites due to difficulties in detecting asbestos at low concentrations and difficulty in extrapolating soil concentrations to air concentrations. Environmental Protection Agency (EPA)’s Office of Land and Emergency Management (OLEM) currently recommends the rigorous process of Activity Based Sampling (ABS) to characterize site exposures. The purpose of this study was to compare three soil analytical methods and two soil sampling methods to determine whether one method, or combination of methods, would yield more reliable soil asbestos data than other methods. Samples were collected using both traditional discrete (“grab”) samples and incremental sampling methodology (ISM). Analyses were conducted using polarized light microscopy (PLM), transmission electron microscopy (TEM) methods or a combination of these two methods. Data show that the fluidized bed asbestos segregator (FBAS) followed by TEM analysis could detect asbestos at locations that were not detected using other analytical methods; however, this method exhibited high relative standard deviations, indicating the results may be more variable than other soil asbestos methods. The comparison of samples collected using ISM versus discrete techniques for asbestos resulted in no clear conclusions regarding preferred sampling method. However, analytical results for metals clearly showed that measured concentrations in ISM samples were less variable than discrete samples. PMID:28759607

  10. TEM Video Compressive Sensing

    SciTech Connect

    Stevens, Andrew J.; Kovarik, Libor; Abellan, Patricia; Yuan, Xin; Carin, Lawrence; Browning, Nigel D.

    2015-08-02

    One of the main limitations of imaging at high spatial and temporal resolution during in-situ TEM experiments is the frame rate of the camera being used to image the dynamic process. While the recent development of direct detectors has provided the hardware to achieve frame rates approaching 0.1ms, the cameras are expensive and must replace existing detectors. In this paper, we examine the use of coded aperture compressive sensing methods [1, 2, 3, 4] to increase the framerate of any camera with simple, low-cost hardware modifications. The coded aperture approach allows multiple sub-frames to be coded and integrated into a single camera frame during the acquisition process, and then extracted upon readout using statistical compressive sensing inversion. Our simulations show that it should be possible to increase the speed of any camera by at least an order of magnitude. Compressive Sensing (CS) combines sensing and compression in one operation, and thus provides an approach that could further improve the temporal resolution while correspondingly reducing the electron dose rate. Because the signal is measured in a compressive manner, fewer total measurements are required. When applied to TEM video capture, compressive imaging couled improve acquisition speed and reduce the electron dose rate. CS is a recent concept, and has come to the forefront due the seminal work of Candès [5]. Since the publication of Candès, there has been enormous growth in the application of CS and development of CS variants. For electron microscopy applications, the concept of CS has also been recently applied to electron tomography [6], and reduction of electron dose in scanning transmission electron microscopy (STEM) imaging [7]. To demonstrate the applicability of coded aperture CS video reconstruction for atomic level imaging, we simulate compressive sensing on observations of Pd nanoparticles and Ag nanoparticles during exposure to high temperatures and other environmental

  11. TEM PSHA2015 Reliability Assessment

    NASA Astrophysics Data System (ADS)

    Lee, Y.; Wang, Y. J.; Chan, C. H.; Ma, K. F.

    2016-12-01

    The Taiwan Earthquake Model (TEM) developed a new probabilistic seismic hazard analysis (PSHA) for determining the probability of exceedance (PoE) of ground motion over a specified period in Taiwan. To investigate the adequacy of the seismic source parameters adopted in the 2015 PSHA of the TEM (TEM PSHA2015), we conducted several tests of the seismic source models. The observed maximal peak ground acceleration (PGA) of the ML > 4.0 mainshocks in the 23-year data period of 1993-2015 were used to test the predicted PGA of PSHA from the areal and subduction zone sources with the time-independent Poisson assumption. This comparison excluded the observations from 1999 Chi-Chi earthquake, as this was the only earthquake associated with the identified active fault in this past 23 years. We used tornado diagrams to analyze the sensitivities of these source parameters to the ground motion values of the PSHA. This study showed that the predicted PGA for a 63% PoE in the 23-year period corresponded to the empirical PGA and the predicted numbers of PGA exceedances to a threshold value 0.1g close to the observed numbers, confirming the parameter applicability for the areal and subduction zone sources. We adopted the disaggregation analysis from a hazard map to determine the contribution of the individual seismic sources to hazard for six metropolitan cities in Taiwan. The sensitivity tests of the seismogenic structure parameters indicated that the slip rate and maximum magnitude are dominant factors for the TEM PSHA2015. For densely populated faults in SW Taiwan, maximum magnitude is more sensitive than the slip rate, giving the concern on the possible multiple fault segments rupture with larger magnitude in this area, which was not yet considered in TEM PSHA2015. The source category disaggregation also suggested that special attention is necessary for subduction zone earthquakes for long-period shaking seismic hazards in Northern Taiwan.

  12. Comparison of analytical techniques for purity evaluation of single-walled carbon nanotubes.

    PubMed

    Itkis, Mikhail E; Perea, Daniel E; Jung, Richard; Niyogi, Sandip; Haddon, Robert C

    2005-03-16

    We compare popular analytical techniques, including scanning and transmission electron microscopy (SEM and TEM), thermogravimetric analysis (TGA), and Raman and near-infrared (NIR) spectroscopy, for the evaluation of the purity of bulk quantities of single-walled carbon nanotubes (SWNTs). Despite their importance as imaging techniques, SEM and TEM are not capable of quantitatively evaluating the purity of typical inhomogeneous bulk SWNT samples because the image frame visualizes less than 1 pg of SWNT material; furthermore, there is no published algorithm to convert such images into numerical data. The TGA technique is capable of measuring the amount of metal catalyst in an SWNT sample, but does not provide an unambiguous separation between the content of SWNTs and carbonaceous impurities. We discuss the utilization of solution-phase near-infrared spectroscopy and solution-phase Raman spectroscopy to quantitatively compare arbitrary samples of bulk SWNT materials of different purities. The primary goal of this paper is to provide the chemical community with a realistic evaluation of current analytical tools for the purity evaluation of a bulk sample of SWNTs. The secondary goal is to draw attention to the growing crisis in the SWNT industry as a result of the lack of quality control and the misleading advertising by suppliers of this material.

  13. COMPARISON OF ANALYTICAL METHODS FOR THE MEASUREMENT OF NON-VIABLE BIOLOGICAL PM

    EPA Science Inventory

    The paper describes a preliminary research effort to develop a methodology for the measurement of non-viable biologically based particulate matter (PM), analyzing for mold, dust mite, and ragweed antigens and endotoxins. Using a comparison of analytical methods, the research obj...

  14. A Comparison of Intensive Behavior Analytic and Eclectic Treatments for Young Children with Autism

    ERIC Educational Resources Information Center

    Howard, Jane S.; Sparkman, Coleen R.; Cohen, Howard G.; Green, Gina; Stanislaw, Harold

    2005-01-01

    We compared the effects of three treatment approaches on preschool-age children with autism spectrum disorders. Twenty-nine children received intensive behavior analytic intervention (IBT; 1:1 adult:child ratio, 25-40 h per week). A comparison group (n=16) received intensive ''eclectic'' intervention (a combination of methods, 1:1 or 1:2 ratio, 30…

  15. A Comparison of Intensive Behavior Analytic and Eclectic Treatments for Young Children with Autism

    ERIC Educational Resources Information Center

    Howard, Jane S.; Sparkman, Coleen R.; Cohen, Howard G.; Green, Gina; Stanislaw, Harold

    2005-01-01

    We compared the effects of three treatment approaches on preschool-age children with autism spectrum disorders. Twenty-nine children received intensive behavior analytic intervention (IBT; 1:1 adult:child ratio, 25-40 h per week). A comparison group (n=16) received intensive ''eclectic'' intervention (a combination of methods, 1:1 or 1:2 ratio, 30…

  16. COMPARISON OF ANALYTICAL METHODS FOR THE MEASUREMENT OF NON-VIABLE BIOLOGICAL PM

    EPA Science Inventory

    The paper describes a preliminary research effort to develop a methodology for the measurement of non-viable biologically based particulate matter (PM), analyzing for mold, dust mite, and ragweed antigens and endotoxins. Using a comparison of analytical methods, the research obj...

  17. Comparison of analytic and numerical bond-order potentials for W and Mo.

    PubMed

    Čák, M; Hammerschmidt, T; Drautz, R

    2013-07-03

    Bond-order potentials (BOPs) are derived from the tight-binding approximation and provide a linearly-scaling computation of the energy and forces for a system of interacting atoms. While the numerical BOPs involve the numerical integration of the response (Green's) function, the expressions for the energy and interatomic forces are analytical within the formalism of the analytic BOPs. In this paper we present a detailed comparison of numerical and analytic BOPs. We use established parametrizations for the bcc refractory metals W and Mo and test structural energy differences; tetragonal, trigonal, hexagonal and orthorhombic deformation paths; formation energies of point defects as well as phonon dispersion relations. We find that the numerical and analytic BOPs generally are in very good agreement for the calculation of energies. Different from the numerical BOPs, the forces in the analytic BOPs correspond exactly to the negative gradients of the energy. This makes it possible to use the analytic BOPs in dynamical simulations and leads to improved predictions of defect energies and phonons as compared to the numerical BOPs.

  18. Comparison of ultramicrotomy and focused-ion-beam for the preparation of TEM and STEM cross section of organic solar cells

    NASA Astrophysics Data System (ADS)

    Corazza, Michael; Simonsen, Søren B.; Gnaegi, Helmut; Thydén, Karl T. S.; Krebs, Frederik C.; Gevorgyan, Suren A.

    2016-12-01

    The challenge of preparing cross sections of organic photovoltaics (OPV) suitable for transmission electron microscopy (TEM) and scanning TEM (STEM) is addressed. The samples were polymer solar cells fabricated using roll-to-roll (R2R) processing methods on a flexible polyethylene terephthalate (PET) substrate. Focused ion beam (FIB) and ultramicrotomy were used to prepare the cross sections. The differences between the samples prepared by ultramicrotomy and FIB are addressed, focusing on the advantages and disadvantages of each technique. The sample prepared by ultramicrotomy yielded good resolution, enabling further studies of phase separation of P3HT:PCBM by means of energy filtered TEM (EFTEM). The sample prepared by FIB shows good structure preservation, but reduced resolution due to non-optimal thicknesses achieved after treatment. Degradation studies of samples prepared by ultramicrotomy are further discussed, which reveal particular effects of the ISOS-L-3 aging test (85 °C, 50% R.H., 0.7 Sun) onto the sample, especially pronounced in the silver layer.

  19. Comparison of potential method in analytic hierarchy process for multi-attribute of catering service companies

    NASA Astrophysics Data System (ADS)

    Mamat, Siti Salwana; Ahmad, Tahir; Awang, Siti Rahmah

    2017-08-01

    Analytic Hierarchy Process (AHP) is a method used in structuring, measuring and synthesizing criteria, in particular ranking of multiple criteria in decision making problems. On the other hand, Potential Method is a ranking procedure in which utilizes preference graph ς (V, A). Two nodes are adjacent if they are compared in a pairwise comparison whereby the assigned arc is oriented towards the more preferred node. In this paper Potential Method is used to solve problem on a catering service selection. The comparison of result by using Potential method is made with Extent Analysis. The Potential Method is found to produce the same rank as Extent Analysis in AHP.

  20. A comparison of analytic models for estimating dose equivalent rates in shielding with beam spill measurements

    SciTech Connect

    Frankle, S.C.; Fitzgerald, D.H.; Hutson, R.L.; Macek, R.J.; Wilkinson, C.A.

    1992-12-31

    A comparison of 800-MeV proton beam spill measurements at the Los Alamos Meson Physics Facility (LAMPF) with analytical model calculations of neutron dose equivalent rates (DER) show agreement within factors of 2-3 for simple shielding geometries. The DER estimates were based on a modified Moyer model for transverse angles and a Monte Carlo based forward angle model described in the proceeding paper.

  1. An analytical comparison of the efficiency of solar thermal collector arrays with and without external manifolds

    NASA Technical Reports Server (NTRS)

    1981-01-01

    An analytical comparison of the efficiency of solar thermal collector arrays with and without external manifolds is reported. A FORTRAN computer program was written for the computation of the thermal performance of solar thermal collector arrays with and without external manifolds. Arrays constructed from two example solar thermal collectors are computated. Typical external manifold sizes and thermal insulations are presented graphically and are compared with the thermal performance of the collector alone.

  2. A comparison of analytical results for 20 K LOX/hydrogen instabilities

    NASA Technical Reports Server (NTRS)

    Klem, Mark D.; Breisacher, Kevin J.

    1990-01-01

    Test data from NASA Lewis' Effect of Thrust Per Element on Combustion Stability Characteristics of Hydrogen-Oxygen Rocket Engines test program are used to validate two recently released stability analysis tools. The first tool is a design methodology called ROCCID (ROCket Combustor Interactive Design). ROCCID is an interactive design and analysis methodology that uses existing performance and combustion stability analysis codes. The second tool is HICCIP (High frequency Injection Coupled Combustion Instability Program). HICCIP is a recently developed combustion stability analysis model. Using a matrix of models, results from analytic comparisons with 20 K LOX/H2 experimental data are presented.

  3. Synthesis of acid-stabilized iron oxide nanoparticles and comparison for targeting atherosclerotic plaques: evaluation by MRI, quantitative MPS, and TEM alternative to ambiguous Prussian blue iron staining.

    PubMed

    Scharlach, Constantin; Kratz, Harald; Wiekhorst, Frank; Warmuth, Carsten; Schnorr, Jörg; Genter, Gesche; Ebert, Monika; Mueller, Susanne; Schellenberger, Eyk

    2015-07-01

    To further optimize citrate-stabilized VSOPs (very small iron oxide particles, developed for MR angiography) for identification of atherosclerotic plaques, we modified their surface during synthesis using eight other acids for electrostatic stabilization. This approach preserves effective production for clinical application. Five particles were suitable to be investigated in targeting plaques of apoE(-/-) mice. Accumulation was evaluated by ex vivo MRI, TEM, and quantitatively by magnetic particle spectroscopy (MPS). Citric- (VSOP), etidronic-, tartaric-, and malic-acid-coated particles accumulated in atherosclerotic plaques with highest accumulation for VSOP (0.2‰ of injected dose). Targets were phagolysosomes of macrophages and of altered endothelial cells. In vivo MRI with VSOP allowed for definite plaque identification. Prussian blue staining revealed abundant endogenous iron in plaques, indistinguishable from particle iron. In apoE(-/-) mice, VSOPs are still the best anionic iron oxide particles for imaging atherosclerotic plaques. MPS allows for quantification of superparamagnetic nanoparticles in such small specimens. The presence of vulnerable plaques in arteries is important for the prediction of acute coronary events. VSOP (very small iron oxide particles, developed for MR angiography) have been shown to be very sensitive in identifying atherosclerotic plaques. The authors studied here further modification to the surface of VSOP during synthesis and compared their efficacy. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Detection of TEM-induced reciprocal translocations in F/sub 1/ sons of CD-1 male mice: comparison of sequential fertility evaluation and cytogenetic analysis

    SciTech Connect

    Morris, S.M.; Kodell, R.L.; Domon, O.E.; Bishop, J.B.

    1988-01-01

    To determine the positive and negative classification error rates associated with the HTA in our laboratory, F/sub 1/ sons of TEM-exposed CD-1 male mice were evaluated by the sequential fertility method with subsequent cytogenetic analysis. Males who sired three litters of size 10 or less when mated to primiparous females from either the B6C3F/sub 1/ or the BCF/sub 1/ strain were classified as partial steriles. When meiotic chromosomes analyses revealed the presence of at least two cells containing multivalent figures, males were classified as translocation heterozygotes. When the fertility evaluation and the cytogenetic analysis were compared, normal fertility was observed on 5 of 83 (6.02%) translocation-bearing F/sub 1/ males mated to B6C3F/sub 1/ tester females and on 3 of 83 (3.61%) F/sub 1/ males mated to BCF/sub 1/ tester females. Thus, the false-negative error rates were 6.02% and 3.61% with these two tester strains. Multivalent figures were not observed in the meiotic chromosomes of 410 F/sub 1/ males. The false-positive error rates with these two tester strains were 2.93% for the B6C3F/sub 1/ strain and 1.71% for the BCF/sub 1/ strain. The results indicate that nonzero error rates, both false-positive and false-negative, are associated with the sequential mating method HTA. In addition, the magnitude of these error rates was influenced not only by the tester female strain but also by the genotype of the F/sub 1/ male.

  5. Comparisons of the five analytic reference lines of the horizontal lip position: their consistency and sensitivity.

    PubMed

    Hsu, B S

    1993-10-01

    One-hundred ten lateral facial profiles were judged to be attractive and were selected from 1000 Taiwanese pupils by a panel of four men and three women from different educational backgrounds. The 110 in the attractive group were analyzed by using five analytic reference lines: Ricketts E line, Holdaway's H line, Steiner's S1 line, Burstone's B line, and Sushner's S2 line. Comparisons of the "consistency" (the smaller coefficient of variation the better the consistency) and the "sensitivity" (the power to differentiate the attractive lateral facial profiles from the unattractive ones) of the five analytic lines were performed. The B line was found to be best in terms of both consistency and sensitivity. From the point of view of convenience, the E line is of great value because its anterior location makes it convenient for the clinician to use. However, the B line appears best from the perspective of the value of reference. This study found that those analytic reference lines that do not transverse an anatomic landmark of the nose most likely have poor consistency and sensitivity. This finding is consistent with the idea that the nose should be taken into consideration when a line is to be used as a reference for beauty on the lateral facial profile.

  6. Direct noise simulation of a canonical high lift device and comparison with an analytical model.

    PubMed

    Salas, Pablo; Fauquembergue, Guillaume; Moreau, Stéphane

    2016-09-01

    The noise of a canonical main-element/flap high-lift device (HLD) is computed directly using compressible wall-resolved Large Eddy Simulation. An experimental database for the chosen configuration allows us to successfully validate the chosen numerical approach. Both the noise sources and the far-field acoustic pressure are shown to be well predicted. Although the two elements trailing-edge noise can be observed in the near field, the flap remains as the dominant source in the far-field. The simplicity of the studied configuration enables the comparison of the validated numerical results with a recently developed analytical model that takes into account the diffraction of the flap noise by the main-element. A two-dimensional (2D) (with and without Kutta condition) and a three-dimensional (without Kutta correction) analytical formulations are compared with the numerical results. All formulations compare favorably with the numerical reference in terms of noise levels and directivities. However, the 2D formulation with a Kutta correction provides the best quantitative agreement as expected from the narrow span of the numerical domain. The recently developed analytical model is therefore a good predictive tool for HLD, showing that it can properly account for the diffraction effect of the main element on the flap main noise source.

  7. In situ TEM of radiation effects in complex ceramics.

    PubMed

    Lian, Jie; Wang, L M; Sun, Kai; Ewing, Rodney C

    2009-03-01

    In situ transmission electron microscopy (TEM) has been extensively applied to study radiation effects in a wide variety of materials, such as metals, ceramics and semiconductors and is an indispensable tool in obtaining a fundamental understanding of energetic beam-matter interactions, damage events, and materials' behavior under intense radiation environments. In this article, in situ TEM observations of radiation effects in complex ceramics (e.g., oxides, silicates, and phosphates) subjected to energetic ion and electron irradiations have been summarized with a focus on irradiation-induced microstructural evolution, changes in microchemistry, and the formation of nanostructures. New results for in situ TEM observation of radiation effects in pyrochlore, A(2)B(2)O(7), and zircon, ZrSiO(4), subjected to multiple beam irradiations are presented, and the effects of simultaneous irradiations of alpha-decay and beta-decay on the microstructural evolution of potential nuclear waste forms are discussed. Furthermore, in situ TEM results of radiation effects in a sodium borosilicate glass subjected to electron-beam exposure are introduced to highlight the important applications of advanced analytical TEM techniques, including Z-contrast imaging, energy filtered TEM (EFTEM), and electron energy loss spectroscopy (EELS), in studying radiation effects in materials microstructural evolution and microchemical changes. By combining ex situ TEM and advanced analytical TEM techniques with in situ TEM observations under energetic beam irradiations, one can obtain invaluable information on the phase stability and response behaviors of materials under a wide range of irradiation conditions.

  8. Comparison of the analytical capabilities of the BAC Datamaster and Datamaster DMT forensic breath testing devices.

    PubMed

    Glinn, Michele; Adatsi, Felix; Curtis, Perry

    2011-11-01

    The State of Michigan uses the Datamaster as an evidential breath testing device. The newest version, the DMT, will replace current instruments in the field as they are retired from service. The Michigan State Police conducted comparison studies to test the analytical properties of the new instrument and to evaluate its response to conditions commonly cited in court defenses. The effects of mouth alcohol, objects in the mouth, and radiofrequency interference on paired samples from drinking subjects were assessed on the DMT. The effects of sample duration and chemical interferents were assessed on both instruments, using drinking subjects and wet-bath simulators, respectively. Our testing shows that Datamaster and DMT results are essentially identical; the DMT gave accurate readings as compared with measurements made using simulators containing standard ethanol solutions and that the DMT did not give falsely elevated breath alcohol results from any of the influences tested. © 2011 American Academy of Forensic Sciences.

  9. Electronic densities of states of semi-infinite disordered chains: Comparisons of exact and analytic calculations

    NASA Astrophysics Data System (ADS)

    Hwang, M.; Podloucky, R.; Gonis, A.; Freeman, A. J.

    1986-01-01

    Results of exact and analytic calculations of the electronic densities of states (DOS's) associated with semi-infinite substitutionally disordered chains are presented using the exact position-space renormalization-group (PSRG) method, the augmented-space (AS) formalism, and the embedded-cluster method (ECM). In addition to total DOS's, the PSRG method allows the calculation of exact partial DOS's associated with local atomic configurations in a disordered material. Comparisons with the exact results indicate that as in the case of infinite materials the ECM provides a reliable method for the calculation of single-particle properties, such as the DOS, of semi-infinite systems. Furthermore, the ECM is found to be much more accurate than the AS formalism, especially in the case of concentrated substitutionally disordered alloys.

  10. Comparison of methods for the estimation of measurement uncertainty for an analytical method for sulphonamides.

    PubMed

    Dabalus Islam, M; Schweikert Turcu, M; Cannavan, A

    2008-12-01

    A simple and inexpensive liquid chromatographic method for the determination of seven sulphonamides in animal tissues was validated. The measurement uncertainty of the method was estimated using two approaches: a 'top-down' approach based on in-house validation data, which used either repeatability data or intra-laboratory reproducibility; and a 'bottom-up' approach, which included repeatability data from spiking experiments. The decision limits (CCalpha) applied in the European Union were calculated for comparison. The bottom-up approach was used to identify critical steps in the analytical procedure, which comprised extraction, concentration, hexane-wash and HPLC-UV analysis. Six replicates of porcine kidney were fortified at the maximum residue limit (100 microg kg(-1)) at three different stages of the analytical procedure, extraction, evaporation, and final wash/HPLC analysis, to provide repeatability data for each step. The uncertainties of the gravimetric and volumetric measurements were estimated and integrated in the calculation of the total combined uncertainties by the bottom-up approach. Estimates for systematic error components were included in both approaches. Combined uncertainty estimates for the seven compounds using the 'top-down' approach ranged from 7.9 to 12.5% (using reproducibility) and from 5.4 to 9.5% (using repeatability data) and from 5.1 to 9.0% using the bottom-up approach. CCalpha values ranged from 105.6 to 108.5 microg kg(-1). The major contributor to the combined uncertainty for each analyte was identified as the extraction step. Since there was no statistical difference between the uncertainty values obtained by either approach, the analyst would be justified in applying the 'top-down' estimation using method validation data, rather than performing additional experiments to obtain uncertainty data.

  11. [Analytical quality of assays and comparison of procedures for the sweat test].

    PubMed

    Nguyen-Khoa, Thao; Borgard, Jean-Pierre; Marchand, Martine; Sitruk-Khalfon, Dominique; Feuillet, Marie-Noëlle; Feldmann, Delphine; Vassault, Anne; Rota, Michèle

    2012-01-01

    Sweat test measuring the chloride ion (Cl(-)) concentration in sweat is a tool for the cystic fibrosis (CF) diagnosis. We evaluated analytical criteria of different available methods and compared them into five hospitals and throught a national quality control program. Sweat tests were performed by stimulation using pilocarpine iontophoresis, sweat collection and measurement of sweat Cl(-) (mmol/L) by titration (colorimetric or coulometric end-point) or by in situ direct potentiometry using a chloride-selective electrode. Indirect determination by sweat conductivity measurement was expressed in mmol/L sodium chloride (NaCl) equivalents (Eq). Linearity range was demonstrated for all measurement procedures in the range 10 to 120 mmol/L. Intra-laboratory coefficients of variation (CVs) were <5% for values between 10 and 100 mmol/L. Inter-laboratory CVs were <3% only for conductivity measurement whatever the range. The comparison of results obtained for a same sweat sample, simultaneously by coulometric and conductivity measurements, demonstrated a first degree linear distribution between 30 to 60 mmol/L Cl(-) allowing us to establish an analytical correspondence table for this range. Thus, calculated values for 30, 40 and 60 mmol/L Cl(-) were respectively 57, 66 and 84 mmol/L NaCl Eq. In conclusion, comparison of methods highlighted that the less the sweat test is automatically controlled, the more the operator influence on results quality is important. Our study supports that sweat test result <50 mmol/L NaCl Eq is unlikely with CF diagnosis in absence of clinical arguments.

  12. An analytical solution for the consideration of the effect of adjacent fuel assemblies; comparison of rectangular and hexagonal structures

    SciTech Connect

    Merk, B.; Rohde, U.

    2012-07-01

    A new analytical method is described to deal with the Leakage Environmental Effect. The method is based on the analytical solution of the two-group diffusion equation for two adjacent fuel assemblies. The quality of the results for this highly efficient method is demonstrated for square fuel assemblies. In additional tests the transferability of the concept to hexagonal VVER-440-type fuel assemblies is shown and a comparison between the results for rectangular and hexagonal assemblies is given. (authors)

  13. Comparison of five analytical methods for the determination of peroxide value in oxidized ghee.

    PubMed

    Mehta, Bhavbhuti M; Darji, V B; Aparnathi, K D

    2015-10-15

    In the present study, a comparison of five peroxide analytical methods was performed using oxidized ghee. The methods included the three iodometric titration viz. Bureau of Indian Standard (BIS), Association of Analytical Communities (AOAC) and American Oil Chemists' Society (AOCS), and two colorimetric methods, the ferrous xylenol orange (FOX) and ferric thiocyanate (International Dairy Federation, IDF) methods based on oxidation of iron. Six ghee samples were stored at 80 °C to accelerate deterioration and sampled periodically (every 48 h) for peroxides. Results were compared using the five methods for analysis as well as a flavor score (9 point hedonic scale). The correlation coefficients obtained using the different methods were in the order: FOX (-0.836) > IDF (-0.821) > AOCS (-0.798) > AOAC (-0.795) > BIS (-0.754). Thus, among the five methods used for determination of peroxide value of ghee during storage, the highest coefficient of correlation was obtained for the FOX method. The high correlations between the FOX and flavor data indicated that FOX was the most suitable method tested to determine peroxide value in oxidized ghee.

  14. Comparison of analytical techniques for the determination of aldehydes in test chambers.

    PubMed

    Salthammer, Tunga; Mentese, Sibel

    2008-11-01

    The level of carbonyl compounds in indoor air is crucial due to possible health effects and the high prevalence of their potential sources. Therefore, selecting a convenient and rapid analytical technique for the reliable detection of carbonyl compound concentrations is important. The acetyl acetone (acac) method is a widely used standard procedure for detecting gaseous formaldehyde. For measuring formaldehyde along with other carbonyl compounds, the DNPH-method is commonly applied. The recommended procedure for measuring volatile organic compounds (VOCs) is sampling on Tenax TA, followed by thermal desorption and GC/MS analysis. In this study, different analytical techniques for the quantification of formaldehyde, pentanal, and hexanal are critically compared. It was found that the acac- and DNPH-method are in very good agreement for formaldehyde. In contrast, the DNPH-method significantly underestimates indoor air concentrations of the higher aldehydes in comparison to sampling on Tenax TA, although both methods are strongly correlated. The reported results are part of the EURIMA-WKI study on levels of indoor air pollutants resulting from construction, building materials and interior decoration.

  15. Comparison of experimental and analytical results for free vibration of laminated composite plates

    SciTech Connect

    Maryuama, Koichi; Narita, Yoshihiro; Ichinomiya, Osamu

    1995-11-01

    Fibrous composite materials are being increasingly employed in high performance structures, including pressured vessel and piping applications. These materials are usually used in the form of laminated flat or curved plates, and the understanding of natural frequencies and the corresponding mode shapes is essential to a reliable structural design. Although many references have been published on analytical study of laminated composite plates, a limited number of experimental studies have appeared for dealing with vibration characteristics of the plates. This paper presents both experimental and analytical results for the problems. In the experiment, the holographic interferometry is used to measure the resonant frequencies and corresponding mode shapes of six-layered CFRP (carbon fiber reinforced plastic) composite plates. The material constants of a lamina are calculated from fiber and matrix material constants by using some different composite rules. With the calculated constants, the natural frequencies of the laminated CFRP plates are theoretically determined by the Ritz method. From the comparison of two sets of the results, the effect of choosing different composite rules is discussed in the vibration study of laminated composite plates.

  16. Comparison of experimental and analytical predictions of rotor blade-vortex interactions using model scale acoustic data

    NASA Technical Reports Server (NTRS)

    Martin, R. M.; Elliott, J. W.; Hoad, D. R.

    1984-01-01

    Helicopter blade-vortex interaction (BVI) noise is studied using a model scale rotor acoustic data base and an analytical rotor wake prediction method. The variation of BVI acoustic levels with vehicle flight conditions (forward speed and disk attitude) is presented. Calculations of probable BVI locations on the rotor disk are made for a range of operating conditions using the measured acoustic signals and an acoustic ray tracing technique. Analytical predictions of possible BVI locations on the rotor disk are made using a generalized distorted wake analysis program. Comparisons of the interaction locations are made with the results of both the analytic approach and the acoustic ray tracing technique.

  17. Quantitative Evaluation of Aged AISI 316L Stainless Steel Sensitization to Intergranular Corrosion: Comparison Between Microstructural Electrochemical and Analytical Methods

    NASA Astrophysics Data System (ADS)

    Sidhom, H.; Amadou, T.; Sahlaoui, H.; Braham, C.

    2007-06-01

    The evaluation of the degree of sensitization (DOS) to intergranular corrosion (IGC) of a commercial AISI 316L austenitic stainless steel aged at temperatures ranging from 550 °C to 800 °C during 100 to 80,000 hours was carried out using three different assessment methods. (1) The microstructural method coupled with the Strauss standard test (ASTM A262). This method establishes the kinetics of the precipitation phenomenon under different aging conditions, by transmission electronic microscope (TEM) examination of thin foils and electron diffraction. The subsequent chromium-depleted zones are characterized by X-ray microanalysis using scanning transmission electronic microscope (STEM). The superimposition of microstructural time-temperature-precipitation (TTP) and ASTM A262 time-temperature-sensitization (TTS) diagrams provides the relationship between aged microstructure and IGC. Moreover, by considering the chromium-depleted zone characteristics, sensitization and desensitization criteria could be established. (2) The electrochemical method involving the double loop-electrochemical potentiokinetic reactivation (DL-EPR) test. The operating conditions of this test were initially optimized using the experimental design method on the bases of the reliability, the selectivity, and the reproducibility of test responses for both annealed and sensitized steels. The TTS diagram of the AISI 316L stainless steel was established using this method. This diagram offers a quantitative assessment of the DOS and a possibility to appreciate the time-temperature equivalence of the IGC sensitization and desensitization. (3) The analytical method based on the chromium diffusion models. Using the IGC sensitization and desensitization criteria established by the microstructural method, numerical solving of the chromium diffusion equations leads to a calculated AISI 316L TTS diagram. Comparison of these three methods gives a clear advantage to the nondestructive DL-EPR test when it is

  18. A comparison of intensive behavior analytic and eclectic treatments for young children with autism.

    PubMed

    Howard, Jane S; Sparkman, Coleen R; Cohen, Howard G; Green, Gina; Stanislaw, Harold

    2005-01-01

    We compared the effects of three treatment approaches on preschool-age children with autism spectrum disorders. Twenty-nine children received intensive behavior analytic intervention (IBT; 1:1 adult:child ratio, 25-40 h per week). A comparison group (n=16) received intensive "eclectic" intervention (a combination of methods, 1:1 or 1:2 ratio, 30 h per week) in public special education classrooms (designated the AP group). A second comparison group (GP) comprised 16 children in non-intensive public early intervention programs (a combination of methods, small groups, 15 h per week). Independent examiners administered standardized tests of cognitive, language, and adaptive skills to children in all three groups at intake and about 14 months after treatment began. The groups were similar on key variables at intake. At follow-up, the IBT group had higher mean standard scores in all skill domains than the AP and GP groups. The differences were statistically significant for all domains except motor skills. There were no statistically significant differences between the mean scores of the AP and GP groups. Learning rates at follow-up were also substantially higher for children in the IBT group than for either of the other two groups. These findings are consistent with other research showing that IBT is considerably more efficacious than "eclectic" intervention.

  19. A Comparison of Four Software Programs for Implementing Decision Analytic Cost-Effectiveness Models.

    PubMed

    Hollman, Chase; Paulden, Mike; Pechlivanoglou, Petros; McCabe, Christopher

    2017-05-09

    The volume and technical complexity of both academic and commercial research using decision analytic modelling has increased rapidly over the last two decades. The range of software programs used for their implementation has also increased, but it remains true that a small number of programs account for the vast majority of cost-effectiveness modelling work. We report a comparison of four software programs: TreeAge Pro, Microsoft Excel, R and MATLAB. Our focus is on software commonly used for building Markov models and decision trees to conduct cohort simulations, given their predominance in the published literature around cost-effectiveness modelling. Our comparison uses three qualitative criteria as proposed by Eddy et al.: "transparency and validation", "learning curve" and "capability". In addition, we introduce the quantitative criterion of processing speed. We also consider the cost of each program to academic users and commercial users. We rank the programs based on each of these criteria. We find that, whilst Microsoft Excel and TreeAge Pro are good programs for educational purposes and for producing the types of analyses typically required by health technology assessment agencies, the efficiency and transparency advantages of programming languages such as MATLAB and R become increasingly valuable when more complex analyses are required.

  20. An experimental comparison of fuzzy logic and analytic hierarchy process for medical decision support systems.

    PubMed

    Uzoka, Faith-Michael Emeka; Obot, Okure; Barker, Ken; Osuji, J

    2011-07-01

    The task of medical diagnosis is a complex one, considering the level vagueness and uncertainty management, especially when the disease has multiple symptoms. A number of researchers have utilized the fuzzy-analytic hierarchy process (fuzzy-AHP) methodology in handling imprecise data in medical diagnosis and therapy. The fuzzy logic is able to handle vagueness and unstructuredness in decision making, while the AHP has the ability to carry out pairwise comparison of decision elements in order to determine their importance in the decision process. This study attempts to do a case comparison of the fuzzy and AHP methods in the development of medical diagnosis system, which involves basic symptoms elicitation and analysis. The results of the study indicate a non-statistically significant relative superiority of the fuzzy technology over the AHP technology. Data collected from 30 malaria patients were used to diagnose using AHP and fuzzy logic independent of one another. The results were compared and found to covary strongly. It was also discovered from the results of fuzzy logic diagnosis covary a little bit more strongly to the conventional diagnosis results than that of AHP. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  1. Polycrystal orientation maps from TEM.

    PubMed

    Fundenberger, J-J; Morawiec, A; Bouzy, E; Lecomte, J S

    2003-08-01

    Determination of topography of crystallite orientations is an important technique of investigation of polycrystalline materials. A system for creating orientation maps using transmission electron microscope (TEM) Kikuchi patterns and Convergent beam electron diffraction patterns is presented. The orientation maps are obtained using a step-by-step beam scan on a computer-controlled TEM equipped with a CCD camera. At each step, acquired diffraction patterns are indexed and orientations are determined. Although, the approach used is similar to that applied in SEM/electron back scattered diffraction (EBSD) orientation imaging setups, the TEM-based system considerably differs from its SEM counterpart. The main differences appear due to specific features of TEM and SEM diffraction patterns. Also, the resulting maps are not equivalent. On these generated by TEM, the accuracy of orientation determination can be better than 0.1 degrees. The spatial resolution is estimated to be about 10nm. The latter feature makes the TEM orientation mapping system an important tool for studies at fine scale unreachable by SEM/EBSD systems. The automatic orientation mapping is expected to be a useful complement of the conventional TEM contrast images. The new technique will be essential for characterization of fine structure materials. To illustrate that, example maps of an aluminum sample produced by severe plastic deformation are included.

  2. Thick Plate Rolling—a Numerical Approach in Comparison with Analytics and Experimental Data

    NASA Astrophysics Data System (ADS)

    Prommer, Hannes; Bojahr, Manuel; Tschullik, Ralf; Kaeding, Patrick

    2011-05-01

    Today, wind turbines are mostly made of glass or carbon fibre. The manufacturing process leads to high precision and quality of the final product. Nevertheless, this fabrication method of rotor blades is very cost intensive and its production technology is not the best in terms of recyclability. In addition to its good recyclability, the handling of steel is well known and its fabrication is inexpensive. Due to these facts an idea of foils to be produced from steel arose. In cooperation with a metal forming company the 3-Dimensional rolling concept came up. Initially, rolling experiments with cold lead plates in a scale of 1:4 are made to simulate the later on used hot steel plates. Such an approach has to be accompanied by fundamental research. This paper sketches the lead rolling experiment and gives an assessment if it is applicable for a hot rolling process with steel. For this purpose, the lead test data are interpreted, the numerical model is explained and results are presented. Furthermore, an analytical flat rolling approach is used to calculate process parameters like stamping force of the upper roll and necessary friction. The applicability and precision of the analytical results are discussed in comparison with the results of the FEM model and the experimental data. Concluding the paper, validity and pitfalls of this concept are outlined and a short outlook for further research is given. The purpose of these considerations is to get closer to process parameters for an experiment in full scale for hot rolling of a rotor blade.

  3. Comparison of thermal analytic model with experimental test results for 30-sentimeter-diameter engineering model mercury ion thruster

    NASA Technical Reports Server (NTRS)

    Oglebay, J. C.

    1977-01-01

    A thermal analytic model for a 30-cm engineering model mercury-ion thruster was developed and calibrated using the experimental test results of tests of a pre-engineering model 30-cm thruster. A series of tests, performed later, simulated a wide range of thermal environments on an operating 30-cm engineering model thruster, which was instrumented to measure the temperature distribution within it. The modified analytic model is described and analytic and experimental results compared for various operating conditions. Based on the comparisons, it is concluded that the analytic model can be used as a preliminary design tool to predict thruster steady-state temperature distributions for stage and mission studies and to define the thermal interface bewteen the thruster and other elements of a spacecraft.

  4. An Analytical Comparison of the Acoustic Analogy and Kirchhoff Formulation for Moving Surfaces

    NASA Technical Reports Server (NTRS)

    Brentner, Kenneth S.; Farassat, F.

    1997-01-01

    The Lighthill acoustic analogy, as embodied in the Ffowcs Williams-Hawkings (FW-H) equation, is compared with the Kirchhoff formulation for moving surfaces. A comparison of the two governing equations reveals that the main Kirchhoff advantage (namely nonlinear flow effects are included in the surface integration) is also available to the FW-H method if the integration surface used in the FW-H equation is not assumed impenetrable. The FW-H equation is analytically superior for aeroacoustics because it is based upon the conservation laws of fluid mechanics rather than the wave equation. This means that the FW-H equation is valid even if the integration surface is in the nonlinear region. This is demonstrated numerically in the paper. The Kirchhoff approach can lead to substantial errors if the integration surface is not positioned in the linear region. These errors may be hard to identify. Finally, new metrics based on the Sobolev norm are introduced which may be used to compare input data for both quadrupole noise calculations and Kirchhoff noise predictions.

  5. Crystal growth of pure substances: Phase-field simulations in comparison with analytical and experimental results

    NASA Astrophysics Data System (ADS)

    Nestler, B.; Danilov, D.; Galenko, P.

    2005-07-01

    A phase-field model for non-isothermal solidification in multicomponent systems [SIAM J. Appl. Math. 64 (3) (2004) 775-799] consistent with the formalism of classic irreversible thermodynamics is used for numerical simulations of crystal growth in a pure material. The relation of this approach to the phase-field model by Bragard et al. [Interface Science 10 (2-3) (2002) 121-136] is discussed. 2D and 3D simulations of dendritic structures are compared with the analytical predictions of the Brener theory [Journal of Crystal Growth 99 (1990) 165-170] and with recent experimental measurements of solidification in pure nickel [Proceedings of the TMS Annual Meeting, March 14-18, 2004, pp. 277-288; European Physical Journal B, submitted for publication]. 3D morphology transitions are obtained for variations in surface energy and kinetic anisotropies at different undercoolings. In computations, we investigate the convergence behaviour of a standard phase-field model and of its thin interface extension at different undercoolings and at different ratios between the diffuse interface thickness and the atomistic capillary length. The influence of the grid anisotropy is accurately analyzed for a finite difference method and for an adaptive finite element method in comparison.

  6. A Dynamic Calibration Method for Experimental and Analytical Hub Load Comparison

    NASA Technical Reports Server (NTRS)

    Kreshock, Andrew R.; Thornburgh, Robert P.; Wilbur, Matthew L.

    2017-01-01

    This paper presents the results from an ongoing effort to produce improved correlation between analytical hub force and moment prediction and those measured during wind-tunnel testing on the Aeroelastic Rotor Experimental System (ARES), a conventional rotor testbed commonly used at the Langley Transonic Dynamics Tunnel (TDT). A frequency-dependent transformation between loads at the rotor hub and outputs of the testbed balance is produced from frequency response functions measured during vibration testing of the system. The resulting transformation is used as a dynamic calibration of the balance to transform hub loads predicted by comprehensive analysis into predicted balance outputs. In addition to detailing the transformation process, this paper also presents a set of wind-tunnel test cases, with comparisons between the measured balance outputs and transformed predictions from the comprehensive analysis code CAMRAD II. The modal response of the testbed is discussed and compared to a detailed finite-element model. Results reveal that the modal response of the testbed exhibits a number of characteristics that make accurate dynamic balance predictions challenging, even with the use of the balance transformation.

  7. Experimental Characterization and Analytical Comparison of Rolling Element Bearing Radial Stiffness

    NASA Technical Reports Server (NTRS)

    Earhart, Eric; Darden, Mark; Strong, Nunley; Chilcoat, Thaddeus; Becht, David

    2010-01-01

    Rocket engine turbopumps often employ rolling element bearings for rotor support. These bearings frequently provide the primary mechanical interface between the stationary and rotating parts, and are relied upon to provide an adequate stiffness characteristic to ensure small rotor deflection due to a variety of sources of radial load. The rotordynamic design of a turbopump, however, requires a more detailed understanding of the bearing's load-deflection characteristic, to accurately predict critical speed location and response. Accordingly, engineers have developed tools to predict the load-deflection relationship for rolling element bearings. These tools allow the engineer to account for rolling element bearing geometric parameters as well as operational parameters, many of which have been shown to significantly influence a bearing's force-deflection characteristics. To that end, a static test rig has been designed, built, and tested to experimentally measure the radial stiffness of a rolling element bearing in a realistic mounting configuration. The objective of this paper is to report these experimental results and provide a comparison to analytical predictions.

  8. A comparison of average wages with age-specific wages for assessing indirect productivity losses: analytic simplicity versus analytic precision.

    PubMed

    Connolly, Mark P; Tashjian, Cole; Kotsopoulos, Nikolaos; Bhatt, Aomesh; Postma, Maarten J

    2017-07-01

    Numerous approaches are used to estimate indirect productivity losses using various wage estimates applied to poor health in working aged adults. Considering the different wage estimation approaches observed in the published literature, we sought to assess variation in productivity loss estimates when using average wages compared with age-specific wages. Published estimates for average and age-specific wages for combined male/female wages were obtained from the UK Office of National Statistics. A polynomial interpolation was used to convert 5-year age-banded wage data into annual age-specific wages estimates. To compare indirect cost estimates, average wages and age-specific wages were used to project productivity losses at various stages of life based on the human capital approach. Discount rates of 0, 3, and 6 % were applied to projected age-specific and average wage losses. Using average wages was found to overestimate lifetime wages in conditions afflicting those aged 1-27 and 57-67, while underestimating lifetime wages in those aged 27-57. The difference was most significant for children where average wage overestimated wages by 15 % and for 40-year-olds where it underestimated wages by 14 %. Large differences in projecting productivity losses exist when using the average wage applied over a lifetime. Specifically, use of average wages overestimates productivity losses between 8 and 15 % for childhood illnesses. Furthermore, during prime working years, use of average wages will underestimate productivity losses by 14 %. We suggest that to achieve more precise estimates of productivity losses, age-specific wages should become the standard analytic approach.

  9. Comparison of the Analytic Hierarchy Process and Incomplete Analytic Hierarchy Process for identifying customer preferences in the Texas retail energy provider market

    NASA Astrophysics Data System (ADS)

    Davis, Christopher

    The competitive market for retail energy providers in Texas has been in existence for 10 years. When the market opened in 2002, 5 energy providers existed, offering, on average, 20 residential product plans in total. As of January 2012, there are now 115 energy providers in Texas offering over 300 residential product plans for customers. With the increase in providers and product plans, customers can be bombarded with information and suffer from the "too much choice" effect. The goal of this praxis is to aid customers in the decision making process of identifying an energy provider and product plan. Using the Analytic Hierarchy Process (AHP), a hierarchical decomposition decision making tool, and the Incomplete Analytic Hierarchy Process (IAHP), a modified version of AHP, customers can prioritize criteria such as price, rate type, customer service, and green energy products to identify the provider and plan that best meets their needs. To gather customer data, a survey tool has been developed for customers to complete the pairwise comparison process. Results are compared for the Incomplete AHP and AHP method to determine if the Incomplete AHP method is just as accurate, but more efficient, than the traditional AHP method.

  10. Study on bird's & insect's wing aerodynamics and comparison of its analytical value with standard airfoil

    NASA Astrophysics Data System (ADS)

    Ali, Md. Nesar; Alam, Mahbubul; Hossain, Md. Abed; Ahmed, Md. Imteaz

    2017-06-01

    by several species of birds. Hovering, which is generating only lift through flapping alone rather than as a product of thrust, demands a lot of energy. On the other hand, for practical knowledge we also fabricate the various bird's, insect's & fighter jet wing by using random value of parameter & test those airfoil in wind tunnel. Finally for comparison & achieving analytical knowledge we also test those airfoil model in various simulation software.

  11. Semi-analytic models for the CANDELS survey: comparison of predictions for intrinsic galaxy properties

    SciTech Connect

    Lu, Yu; Wechsler, Risa H.; Somerville, Rachel S.; Croton, Darren; Porter, Lauren; Primack, Joel; Moody, Chris; Behroozi, Peter S.; Ferguson, Henry C.; Koo, David C.; Guo, Yicheng; Finlator, Kristian; Castellano, Marco; Sommariva, Veronica E-mail: rwechsler@stanford.edu

    2014-11-10

    We compare the predictions of three independently developed semi-analytic galaxy formation models (SAMs) that are being used to aid in the interpretation of results from the CANDELS survey. These models are each applied to the same set of halo merger trees extracted from the 'Bolshoi' high-resolution cosmological N-body simulation and are carefully tuned to match the local galaxy stellar mass function using the powerful method of Bayesian Inference coupled with Markov Chain Monte Carlo or by hand. The comparisons reveal that in spite of the significantly different parameterizations for star formation and feedback processes, the three models yield qualitatively similar predictions for the assembly histories of galaxy stellar mass and star formation over cosmic time. Comparing SAM predictions with existing estimates of the stellar mass function from z = 0-8, we show that the SAMs generally require strong outflows to suppress star formation in low-mass halos to match the present-day stellar mass function, as is the present common wisdom. However, all of the models considered produce predictions for the star formation rates (SFRs) and metallicities of low-mass galaxies that are inconsistent with existing data. The predictions for metallicity-stellar mass relations and their evolution clearly diverge between the models. We suggest that large differences in the metallicity relations and small differences in the stellar mass assembly histories of model galaxies stem from different assumptions for the outflow mass-loading factor produced by feedback. Importantly, while more accurate observational measurements for stellar mass, SFR and metallicity of galaxies at 1 < z < 5 will discriminate between models, the discrepancies between the constrained models and existing data of these observables have already revealed challenging problems in understanding star formation and its feedback in galaxy formation. The three sets of models are being used to construct catalogs of mock

  12. Verification of a magnetic island in gyro-kinetics by comparison with analytic theory

    SciTech Connect

    Zarzoso, D. Casson, F. J.; Poli, E.; Hornsby, W. A.; Peeters, A. G.

    2015-02-15

    A rotating magnetic island is imposed in the gyrokinetic code GKW, when finite differences are used for the radial direction, in order to develop the predictions of analytic tearing mode theory and understand its limitations. The implementation is verified against analytics in sheared slab geometry with three numerical tests that are suggested as benchmark cases for every code that imposes a magnetic island. The convergence requirements to properly resolve physics around the island separatrix are investigated. In the slab geometry, at low magnetic shear, binormal flows inside the island can drive Kelvin-Helmholtz instabilities which prevent the formation of the steady state for which the analytic theory is formulated.

  13. A comparison of intra- and interjudge decision consistencies using analytic and holistic scoring criteria.

    PubMed

    Lunz, M E; Stahl, J A

    1990-01-01

    This study explored the effect of scoring criteria on the decision consistency of judges. Intra- and interjudge consistencies were compared when two different scoring criteria were used by the same judges. Analytic criteria included detailed assessments of a student's performance, while holistic criteria included only a subjective global assessment. Data from 18 judges and 9 histotechnology practical examinations were analyzed. Lack of intrajudge decision consistency was observed when the same practical examinations were assessed using analytic and holistic criteria. Interjudge decision consistency also varied when the different scoring criteria were used. More practical examinations were judged as passing when analytic scoring criteria were used. This particular analysis did not support a definitive conclusion concerning the value of holistic and analytic criteria.

  14. Comparison of analytic Whipple bumper shield ballistic limits with CTH simulations

    SciTech Connect

    Hertel, E.S. Jr.

    1993-05-01

    A series of CTH simulations were conducted to assess the feasibility of using the hydrodynamic code for debris cloud formation and to predict any damage due to the subsequent loading on rear structures. Six axisymmetric and one 3-dimensional simulations were conducted for spherical projectiles impacting Whipple bumper shields. The projectile diameters were chosen to correlate with two well known analytic expressions for the ballistic limit of a Whipple bumper shield. It has been demonstrated that CTH can be used to simulate the debris cloud formation, the propagation of the debris across a void region, and the secondary impact of the debris against a structure. In addition, the results from the CTH simulations were compared to the analytic estimates of the ballistic limit. At impact velocities of 10 km/s or less, the CTH predicted ballistic limit lays between the two analytic estimates. However, for impact velocities greater than 10 km/s, CTH simulations predicted a ballistic limit larger than both analytical estimates. The differences at high velocities are not well understood. Structural failure at late times due to the time integrated loading of a very diffuse debris cloud has not been considered in the CTH model. In addition, the analytic predictions are extrapolated from relatively low velocity data and the extrapolation technique may not be valid. The discrepancy between the two techniques should be investigated further.

  15. Comparison of analytical and clinical performance of three methods for detection of Clostridium difficile.

    PubMed

    LaSala, P Rocco; Svensson, Annika M; Mohammad, Amin A; Perrotta, Peter L

    2012-05-01

    Diagnostic laboratory testing for Clostridium difficile infection has undergone considerable and rapid evolution during the last decade. The ideal detection method(s), which should exhibit high analytical and clinical sensitivity and specificity, remains undefined. We sought to evaluate the analytical and clinical performance characteristics of three methods for the laboratory detection of C difficile. This study used 114 consecutive stool samples to compare three methods of C difficile detection: an enzyme immunoassay (EIA) for toxins A/B, a lateral flow membrane immunoassay for glutamate dehydrogenase (GDH), and a qualitative real-time polymerase chain reaction (PCR) assay. Medical records of all patients having ≥1 positive test result were reviewed to estimate the clinical likelihood of C difficile infection. Based upon laboratory result consensus values, analytical sensitivity was significantly higher for GDH (94%) and PCR (94%) assays than for toxin EIA (25%). Analytical specificity was significantly higher for PCR (100%) and EIA (100%) than for GDH assay (93%). In contrast, assay performance based upon clinical probability of C difficile infection suggested lower discriminatory power (ie, clinical specificity) of the more analytically sensitive methods. Higher rates of C difficile detection will be realized upon implementation of GDH assay and/or real-time PCR-based testing algorithms than by testing with EIA alone. Further study is required to elucidate potential downstream costs for higher detection rates.

  16. A comparison between observed and analytical velocity dispersion profiles of 20 nearby galaxy clusters

    NASA Astrophysics Data System (ADS)

    Khan, Mohammad S.; Abdullah, Mohamed H.; Ali, Gamal B.

    2014-05-01

    We derive analytical expression for the velocity dispersion of galaxy clusters, using the statistical mechanical approach. We compare the observed velocity dispersion profiles for 20 nearby ( z≤0.1) galaxy clusters with the analytical ones. It is interesting to find that the analytical results closely match with the observed velocity dispersion profiles only if the presence of the diffuse matter in clusters is taken into consideration. This takes us to introduce a new approach to detect the ratio of diffuse mass, M diff , within a galaxy cluster. For the present sample, the ratio f= M diff / M, where M the cluster's total mass is found to has an average value of 45±12 %. This leads us to the result that nearly 45 % of the cluster mass is impeded outside the galaxies, while around 55 % of the cluster mass is settled in the galaxies.

  17. A Comparison of Experimental and Analytical Procedures to Measure Passive Drag in Human Swimming

    PubMed Central

    Barbosa, Tiago M.; Morais, Jorge E.; Forte, Pedro; Neiva, Henrique; Garrido, Nuno D.; Marinho, Daniel A.

    2015-01-01

    The aim of this study was to compare the swimming hydrodynamics assessed with experimental and analytical procedures, as well as, to learn about the relative contributions of the friction drag and pressure drag to total passive drag. Sixty young talented swimmers (30 boys and 30 girls with 13.59±0.77 and 12.61±0.07 years-old, respectively) were assessed. Passive drag was assessed with inverse dynamics of the gliding decay speed. The theoretical modeling included a set of analytical procedures based on naval architecture adapted to human swimming. Linear regression models between experimental and analytical procedures showed a high correlation for both passive drag (Dp = 0.777*Df+pr; R2 = 0.90; R2a = 0.90; SEE = 8.528; P<0.001) and passive drag coefficient (CDp = 1.918*CDf+pr; R2 = 0.96; R2a = 0.96; SEE = 0.029; P<0.001). On average the difference between methods was -7.002N (95%CI: -40.480; 26.475) for the passive drag and 0.127 (95%CI: 0.007; 0.247) for the passive drag coefficient. The partial contribution of friction drag and pressure drag to total passive drag was 14.12±9.33% and 85.88±9.33%, respectively. As a conclusion, there is a strong relationship between the passive drag and passive drag coefficient assessed with experimental and analytical procedures. The analytical method is a novel, feasible and valid way to gather insight about one’s passive drag during training and competition. Analytical methods can be selected not only to perform race analysis during official competitions but also to monitor the swimmer’s status on regular basis during training sessions without disrupting or time-consuming procedures. PMID:26207364

  18. A Comparison of Experimental and Analytical Procedures to Measure Passive Drag in Human Swimming.

    PubMed

    Barbosa, Tiago M; Morais, Jorge E; Forte, Pedro; Neiva, Henrique; Garrido, Nuno D; Marinho, Daniel A

    2015-01-01

    The aim of this study was to compare the swimming hydrodynamics assessed with experimental and analytical procedures, as well as, to learn about the relative contributions of the friction drag and pressure drag to total passive drag. Sixty young talented swimmers (30 boys and 30 girls with 13.59±0.77 and 12.61±0.07 years-old, respectively) were assessed. Passive drag was assessed with inverse dynamics of the gliding decay speed. The theoretical modeling included a set of analytical procedures based on naval architecture adapted to human swimming. Linear regression models between experimental and analytical procedures showed a high correlation for both passive drag (Dp = 0.777*Df+pr; R2 = 0.90; R2a = 0.90; SEE = 8.528; P<0.001) and passive drag coefficient (CDp = 1.918*CDf+pr; R2 = 0.96; R2a = 0.96; SEE = 0.029; P<0.001). On average the difference between methods was -7.002N (95%CI: -40.480; 26.475) for the passive drag and 0.127 (95%CI: 0.007; 0.247) for the passive drag coefficient. The partial contribution of friction drag and pressure drag to total passive drag was 14.12±9.33% and 85.88±9.33%, respectively. As a conclusion, there is a strong relationship between the passive drag and passive drag coefficient assessed with experimental and analytical procedures. The analytical method is a novel, feasible and valid way to gather insight about one's passive drag during training and competition. Analytical methods can be selected not only to perform race analysis during official competitions but also to monitor the swimmer's status on regular basis during training sessions without disrupting or time-consuming procedures.

  19. Analytical electron microscopy of Mg-SiO smokes - A comparison with infrared and XRD studies

    NASA Technical Reports Server (NTRS)

    Rietmeijer, F. J. M.; Nuth, J. A.; Mackinnon, I. D. R.

    1986-01-01

    Analytical electron microscopy conducted for Mg-SiO smokes (experimentally obtained from samples previously characterized by IR spectroscopy) indicates that the microcrystallinity content of unannealed smokes increases with increased annealing for up to 30 hr. The growth of forsterite microcrystallites in the initially nonstoichiometric smokes may give rise to the contemporaneous growth of the SiO polymorph tridymite and MgO; after 4 hr of annealing, these react to form enstatite. It is suggested that XRD analysis and IR spectroscopy should be conducted in conjunction with detailed analytical electron microscopy for the detection of emerging crystallinity in vapor-phase condensates.

  20. Inter-comparison exercises on dissolved gases for groundwater dating (GDAT 2012) : analytical uncertainties, apparent ages and other derived parameters.

    NASA Astrophysics Data System (ADS)

    Labasque, Thierry; Aquilina, Luc; Visser, Ate; Vergnaud, Virginie

    2014-05-01

    An inter-laboratory comparison exercise dedicated to environmental tracers used for groundwater dating was organized in 2012 in France. The goal was to compare sampling and analytical protocols through results obtained by the community of groundwater dating laboratories. Sampling and analytical protocols were compared through three different exercises on various supports : (1) on groundwater from a homogeneous aquifer, (2) on groundwater from a fractured heterogeneous aquifer and (3) on an air standard. The two tests allowed 31 Laboratories from 14 countries to compare their protocols for both sampling and analyses. It allows discussing the uncertainties related to sampling protocols issuing from each laboratory methods. The results show a good agreement between laboratories on the aquifers and the air standard. The dispersion of SF6 results in air standard is low (rsd 2%) compared to CFCs (rsd 3 to 7%), even if its concentration is two orders of magnitude lower. Results obtained in recent groundwater (recharge after 1980) show that the uncertainty on groundwater dating with SF6 is between 3 and 4 years. This large uncertainty is mainly due to sampling and/or analytical problems. For CFCs, uncertainties obtained over all the laboratories are less than 2 years for groundwater with recharge between 1965 and 1996. The goal of the inter-laboratory comparison exercise was also to quantify the analytical uncertainty of the 3H and noble gas measurements and to assess whether they meet the requirements for 3H/3He dating and noble gas paleotemperature reconstruction. The reproducibility of the tritium measurements was 13.5%. The reproducibility of the 3He/4He ratio and 4He, Ne, Ar, Kr and Xe concentrations was 1.4%, 1.8%, 1.5%, 2.2%, 2.9%, and 2.4%. The propagated uncertainty of the tritium and noble gas measurements meets the desired precision for typical 3H/3He dating applications. However, the measurement uncertainties for the noble gas concentrations are insufficient to

  1. A comparison of numerical and semi-analytical methods for the case of heat transfer equations arising in porous medium

    NASA Astrophysics Data System (ADS)

    Parand, K.; Rad, J. A.; Ahmadi, M.

    2016-09-01

    Natural convective heat transfer in porous media which is of importance in the design of canisters for nuclear waste disposal has received considerable attention during the past few decades. This paper presents a comparison between two different analytical and numerical methods, i.e. pseudospectral and Adomian decomposition methods. The pseudospectral approach makes use of the orthogonal rational Jacobi functions; this method reduces the solution of the problem to a solution of a system of algebraic equations. Numerical results are compared with each other, showing that the pseudospectral method leads to more accurate results and is applicable on similar problems.

  2. Comparison of input parameters regarding rock mass in analytical solution and numerical modelling

    NASA Astrophysics Data System (ADS)

    Yasitli, N. E.

    2016-12-01

    Characteristics of stress redistribution around a tunnel excavated in rock are of prime importance for an efficient tunnelling operation and maintaining stability. As it is a well known fact that rock mass properties are the most important factors affecting stability together with in-situ stress field and tunnel geometry. Induced stresses and resultant deformation around a tunnel can be approximated by means of analytical solutions and application of numerical modelling. However, success of these methods depends on assumptions and input parameters which must be representative for the rock mass. However, mechanical properties of intact rock can be found by laboratory testing. The aim of this paper is to demonstrate the importance of proper representation of rock mass properties as input data for analytical solution and numerical modelling. For this purpose, intact rock data were converted into rock mass data by using the Hoek-Brown failure criterion and empirical relations. Stress-deformation analyses together with yield zone thickness determination have been carried out by using analytical solutions and numerical analyses by using FLAC3D programme. Analyses results have indicated that incomplete and incorrect design causes stability and economic problems in the tunnel. For this reason during the tunnel design analytical data and rock mass data should be used together. In addition, this study was carried out to prove theoretically that numerical modelling results should be applied to the tunnel design for the stability and for the economy of the support.

  3. A Comparison of Numerical and Analytical Radiative-Transfer Solutions for Plane Albedo in Natural Waters

    EPA Science Inventory

    Several numerical and analytical solutions of the radiative transfer equation (RTE) for plane albedo were compared for solar light reflection by sea water. The study incorporated the simplest case, that being a semi-infinite one-dimensional plane-parallel absorbing and scattering...

  4. A Comparison of Numerical and Analytical Radiative-Transfer Solutions for Plane Albedo in Natural Waters

    EPA Science Inventory

    Several numerical and analytical solutions of the radiative transfer equation (RTE) for plane albedo were compared for solar light reflection by sea water. The study incorporated the simplest case, that being a semi-infinite one-dimensional plane-parallel absorbing and scattering...

  5. Comparison of experimental coupled helicopter rotor/body stability results with a simple analytical model

    NASA Technical Reports Server (NTRS)

    Friedmann, P. P.; Venkatesan, C.

    1988-01-01

    The results of an analytical study aimed at predicting the aeromechanical stability of a helicopter in ground resonance, with the inclusion of aerodynamic forces are presented. The theoretical results are found to be in good agreement with the experimental results, available in literature, indicating that the coupled rotor/fuselage system can be represented by a reasonably simple mathematical model.

  6. Classical Test Theory and Item Response Theory: Analytical and Empirical Comparisons.

    ERIC Educational Resources Information Center

    Hwang, Dae-Yeop

    This study compared classical test theory (CTT) and item response theory (IRT). The behavior of the item and person statistics derived from these two measurement frameworks was examined analytically and empirically using a data set obtained from BILOG (R. Mislay and D. Block, 1997). The example was a 15-item test with a sample size of 600…

  7. Comparison of commercial analytical techniques for measuring chlorine dioxide in urban desalinated drinking water.

    PubMed

    Ammar, T A; Abid, K Y; El-Bindary, A A; El-Sonbati, A Z

    2015-12-01

    Most drinking water industries are closely examining options to maintain a certain level of disinfectant residual through the entire distribution system. Chlorine dioxide is one of the promising disinfectants that is usually used as a secondary disinfectant, whereas the selection of the proper monitoring analytical technique to ensure disinfection and regulatory compliance has been debated within the industry. This research endeavored to objectively compare the performance of commercially available analytical techniques used for chlorine dioxide measurements (namely, chronoamperometry, DPD (N,N-diethyl-p-phenylenediamine), Lissamine Green B (LGB WET) and amperometric titration), to determine the superior technique. The commonly available commercial analytical techniques were evaluated over a wide range of chlorine dioxide concentrations. In reference to pre-defined criteria, the superior analytical technique was determined. To discern the effectiveness of such superior technique, various factors, such as sample temperature, high ionic strength, and other interferences that might influence the performance were examined. Among the four techniques, chronoamperometry technique indicates a significant level of accuracy and precision. Furthermore, the various influencing factors studied did not diminish the technique's performance where it was fairly adequate in all matrices. This study is a step towards proper disinfection monitoring and it confidently assists engineers with chlorine dioxide disinfection system planning and management.

  8. TH-A-19A-06: Site-Specific Comparison of Analytical and Monte Carlo Based Dose Calculations

    SciTech Connect

    Schuemann, J; Grassberger, C; Paganetti, H; Dowdell, S

    2014-06-15

    Purpose: To investigate the impact of complex patient geometries on the capability of analytical dose calculation algorithms to accurately predict dose distributions and to verify currently used uncertainty margins in proton therapy. Methods: Dose distributions predicted by an analytical pencilbeam algorithm were compared with Monte Carlo simulations (MCS) using TOPAS. 79 complete patient treatment plans were investigated for 7 disease sites (liver, prostate, breast, medulloblastoma spine and whole brain, lung and head and neck). A total of 508 individual passively scattered treatment fields were analyzed for field specific properties. Comparisons based on target coverage indices (EUD, D95, D90 and D50) were performed. Range differences were estimated for the distal position of the 90% dose level (R90) and the 50% dose level (R50). Two-dimensional distal dose surfaces were calculated and the root mean square differences (RMSD), average range difference (ARD) and average distal dose degradation (ADD), the distance between the distal position of the 80% and 20% dose levels (R80- R20), were analyzed. Results: We found target coverage indices calculated by TOPAS to generally be around 1–2% lower than predicted by the analytical algorithm. Differences in R90 predicted by TOPAS and the planning system can be larger than currently applied range margins in proton therapy for small regions distal to the target volume. We estimate new site-specific range margins (R90) for analytical dose calculations considering total range uncertainties and uncertainties from dose calculation alone based on the RMSD. Our results demonstrate that a reduction of currently used uncertainty margins is feasible for liver, prostate and whole brain fields even without introducing MC dose calculations. Conclusion: Analytical dose calculation algorithms predict dose distributions within clinical limits for more homogeneous patients sites (liver, prostate, whole brain). However, we recommend

  9. On the new analytical solution for a well in Cartesian coordinates with MODFLOW comparisons.

    PubMed

    Batu, Vedat

    2014-01-01

    In this paper, the comparison process of Batu (2012) generalized three-dimensional well hydraulics solution for confined aquifers in Cartesian coordinates with MODFLOW is presented. First, a brief description of Batu (2012) solution along with the governing equations and some of its key features are described. The final average drawdown expression in an observation well is given with the conversion expressions from Cartesian to radial coordinates. A generalized comparison using Batu (2012), Hantush (1964), and MODFLOW (Harbaugh et al. 2000), for vertical wells in horizontally isotropic aquifers, that is, ayx  = Ky /Kx  = 1, is presented. Comparisons are also presented with Batu (2012) and MODFLOW for horizontally anisotropic aquifers, that is, ayx  ≠ 1. After that comparisons are presented for horizontal wells between Batu (2012) and MODFLOW.

  10. Comparison of analytical methods used to measure petroleum hydrocarbons in soils and their applications to bioremediation

    SciTech Connect

    Douglas, G.S.; McMillen, S.J.

    1996-10-01

    Chemical measurements provide a means to evaluate crude oil and refined product bioremediation effectiveness in field and laboratory studies. These measurements are used to determine the net decrease in product or target compound concentrations in complex soil systems. The analytical methods used to evaluate these constituents will have a direct impact on the ability of the investigator to; (1) detect losses due to biodegradation, (2) understand the processes responsible for the hydrocarbon degradation and, (3) determine the rates of hydrocarbon degradation. The applications and limitations of standard EPA methodologies (EPA Methods 418.1, 8270, and modified 8015) will be evaluated in soil mesocosm petroleum biodegradation studies and compared to several new analytical methods currently being used by the petroleum industry [gross compositional analysis, TLC-FID analysis, and enhanced EPA Method 8270 (e.g., C30-17{alpha}(H),21{beta}(H)-hopane)] to evaluate bioremediation effectiveness in soils.

  11. Comparison of the analytical performance of electrophoresis microchannels fabricated in PDMS, glass, and polyester-toner.

    PubMed

    Coltro, Wendell Karlos Tomazelli; Lunte, Susan M; Carrilho, Emanuel

    2008-12-01

    This paper compares the analytical performance of microchannels fabricated in PDMS, glass, and polyester-toner for electrophoretic separations. Glass and PDMS chips were fabricated using well-established photolithographic and replica-molding procedures, respectively. PDMS channels were sealed against three different types of materials: native PDMS, plasma-oxidized PDMS, and glass. Polyester-toner chips were micromachined by a direct-printing process using an office laser printer. All microchannels were fabricated with similar dimensions according to the limitations of the direct-printing process (width/depth 150 microm/12 microm). LIF was employed for detection to rule out any losses in separation efficiency due to the detector configuration. Two fluorescent dyes, coumarin and fluorescein, were used as model analytes. Devices were evaluated for the following parameters related to electrophoretic separations: EOF, heat dissipation, injection reproducibility, separation efficiency, and adsorption to channel wall.

  12. Slow rarefied gas flow past a cylinder: Analytical solution in comparison to the sphere

    NASA Astrophysics Data System (ADS)

    Westerkamp, Armin; Torrilhon, Manuel

    2012-11-01

    In the variety of approaches to tackle the challenges of rarefied gas flows, the regularized 13-moment equations (R13) have become a very promising contender. The equations are based on moment approximations in kinetic gas theory which can be interpreted as a non-linear discretization of the Boltzmann equation in the velocity space. In order to get a deeper insight into rarefaction effects, an analytic solution for the flow around a sphere has been constructed in [M. Torrilhon, Phys. Fluids. 22, 072001:1-16 (2010)]. In the present work, an analytic solution for the flow past a cylinder is derived, which is another very important text book problem. Again, the investigation is restricted to slow flows (Ma ≪ 1), which means a linearized system of the original R13 equations is analyzed. The results for the sphere and the cylinder are then compared and typical rarefaction effects are pointed out.

  13. A comparison of analytical techniques for evaluating food waste degradation by anaerobic digestion.

    PubMed

    Gómez, X; Cuetos, M J; Tartakovsky, B; Martínez-Núñez, M F; Morán, A

    2010-05-01

    Organic matter contained in food waste was degraded by anaerobic digestion under mesophilic and thermophilic conditions at two hydraulic retention times. Evolution of the digestion process was followed by thermogravimetry analysis, fluorescence spectroscopy and (1)H nuclear magnetic resonance. All analytical methods suggested that longer retention times might be required for food waste stabilization under mesophilic conditions as compared to thermophilic stabilization. All the analytical methods showed that the stabilization process consisted of two steps, where complex organic molecules were formed during initial stabilization and then digested providing sufficient hydraulic retention time. Longer hydraulic retention times were required for food waste stabilization under mesophilic conditions. Overall, thermal and (1)H NMR analyses of the digestate samples might be recommended if more detailed analysis is required, while fluorescence measurements can be used as a fast screening technique, which provides qualitative assessment of the stabilization process.

  14. Comparison of analytical and flight test identified aerodynamic derivatives for a tandem-rotor transport helicopter

    NASA Technical Reports Server (NTRS)

    Hodge, W. F.

    1980-01-01

    Flight tests for verifying an analytical aerodynamic derivative model of a CH-47 helicopter were conducted for low cruise speeds and transition to hover portions of curved, decelerating landing approach trajectories. All testing was performed on a closed loop basis with the stability augmentation system of the helicopter operating, and response data were obtained using both manual and computer generated input maneuvers. The results indicate some differences between the measured response time histories and those predicted by both analytical and flight test identified derivatives. With some exceptions the discrepancies are not severe, and the overall agreement between the measured and computed time histories is reasonably good. No adverse effects attributable to closed loop testing were noted, and the use of computer generated inputs proved to be superior to manual ones.

  15. Comparison of the analytical performance of electrophoresis microchannels fabricated in PDMS, glass, and polyester-toner

    PubMed Central

    Coltro, Wendell Karlos Tomazelli; Lunte, Susan M.; Carrilho, Emanuel

    2008-01-01

    This paper compares the analytical performance of microchannels fabricated in PDMS, glass, and polyester-toner for electrophoretic separations. Glass and PDMS chips were fabricated using well-established photolithographic and replica-molding procedures, respectively. PDMS channels were sealed against three different types of materials: native PDMS, plasma-oxidized PDMS, and glass. Polyester-toner chips were micromachined by a direct-printing process using an office laser printer. All microchannels were fabricated with similar dimensions according to the limitations of the direct-printing process (width/depth 150 μm/12 μm). LIF was employed for detection to rule out any losses in separation efficiency due to the detector configuration. Two fluorescent dyes, coumarin and fluorescein, were used as model analytes. Devices were evaluated for the following parameters related to electrophoretic separations: EOF, heat dissipation, injection reproducibility, separation efficiency, and adsorption to channel wall. PMID:19025869

  16. A comparison of analytical approaches for wellbore heat transmission in layered formations

    SciTech Connect

    Wu, Yu-Shu.

    1988-08-01

    This report presents an analytical method for determining wellbore heat transmission during liquid or gas flow along the tubing. The mathematical model describes the heat transfer between the flowing fluid in the wellbore and in the surrounding formation as one whole physical system. The transient heat transfer equations in the two regions with coupling at the sandface are solved simultaneously. Non-homogeneous formations are treated which consist of several layers with different physical properties and arbitrary initial temperature distributions in the vertical direction. Closed form analytical solutions are obtained in real space and in Laplace space, which can be used to calculate the temperature distribution along the wellbore and in the formation, and to evaluate heat transfer rate and cumulative heat exchange between wellbore and formation. A more accurate formula is given for the widely-used transient heat conduction function f(t{sub D}) of thermal resistance. 14 refs., 12 figs., 1 tab.

  17. Teaching dermatoscopy of pigmented skin tumours to novices: comparison of analytic vs. heuristic approach.

    PubMed

    Tschandl, P; Kittler, H; Schmid, K; Zalaudek, I; Argenziano, G

    2015-06-01

    There are two strategies to approach the dermatoscopic diagnosis of pigmented skin tumours, namely the verbal-based analytic and the more visual-global heuristic method. It is not known if one or the other is more efficient in teaching dermatoscopy. To compare two teaching methods in short-term training of dermatoscopy to medical students. Fifty-seven medical students in the last year of the curriculum were given a 1-h lecture of either the heuristic- or the analytic-based teaching of dermatoscopy. Before and after this session, they were shown the same 50 lesions and asked to diagnose them and rate for chance of malignancy. Test lesions consisted of melanomas, basal cell carcinomas, nevi, seborrhoeic keratoses, benign vascular tumours and dermatofibromas. Performance measures were diagnostic accuracy regarding malignancy as measured by the area under the curves of receiver operating curves (range: 0-1), as well as per cent correct diagnoses (range: 0-100%). Diagnostic accuracy as well as per cent correct diagnoses increased by +0.21 and +32.9% (heuristic teaching) and +0.19 and +35.7% (analytic teaching) respectively (P for all <0.001). Neither for diagnostic accuracy (P = 0.585), nor for per cent correct diagnoses (P = 0.298) was a difference between the two groups. Short-term training of dermatoscopy to medical students allows significant improvement in diagnostic abilities. Choosing a heuristic or analytic method does not have an influence on this effect in short training using common pigmented skin lesions. © 2014 European Academy of Dermatology and Venereology.

  18. A multigroup radiation diffusion test problem: Comparison of code results with analytic solution

    SciTech Connect

    Shestakov, A I; Harte, J A; Bolstad, J H; Offner, S R

    2006-12-21

    We consider a 1D, slab-symmetric test problem for the multigroup radiation diffusion and matter energy balance equations. The test simulates diffusion of energy from a hot central region. Opacities vary with the cube of the frequency and radiation emission is given by a Wien spectrum. We compare results from two LLNL codes, Raptor and Lasnex, with tabular data that define the analytic solution.

  19. Predicting playing frequencies for clarinets: A comparison between numerical simulations and simplified analytical formulas.

    PubMed

    Coyle, Whitney L; Guillemain, Philippe; Kergomard, Jean; Dalmont, Jean-Pierre

    2015-11-01

    When designing a wind instrument such as a clarinet, it can be useful to be able to predict the playing frequencies. This paper presents an analytical method to deduce these playing frequencies using the input impedance curve. Specifically there are two control parameters that have a significant influence on the playing frequency, the blowing pressure and reed opening. Four effects are known to alter the playing frequency and are examined separately: the flow rate due to the reed motion, the reed dynamics, the inharmonicity of the resonator, and the temperature gradient within the clarinet. The resulting playing frequencies for the first register of a particular professional level clarinet are found using the analytical formulas presented in this paper. The analytical predictions are then compared to numerically simulated results to validate the prediction accuracy. The main conclusion is that in general the playing frequency decreases above the oscillation threshold because of inharmonicity, then increases above the beating reed regime threshold because of the decrease of the flow rate effect.

  20. A Comparison of Analytical and Experimental Data for a Magnetic Actuator

    NASA Technical Reports Server (NTRS)

    Groom, Nelson J.; Bloodgood, V. Dale, Jr.

    2000-01-01

    Theoretical and experimental force-displacement and force-current data are compared for two configurations of a simple horseshoe, or bipolar, magnetic actuator. One configuration utilizes permanent magnet wafers to provide a bias flux and the other configuration has no source of bias flux. The theoretical data are obtained from two analytical models of each configuration. One is an ideal analytical model which is developed under the following assumptions: (1) zero fringing and leakage flux, (2) zero actuator coil mmf loss, and (3) infinite permeability of the actuator core and suspended element flux return path. The other analytical model, called the extended model, is developed by adding loss and leakage factors to the ideal model. The values of the loss and leakage factors are calculated from experimental data. The experimental data are obtained from a magnetic actuator test fixture, which is described in detail. Results indicate that the ideal models for both configurations do not match the experimental data very well. However, except for the range around zero force, the extended models produce a good match. The best match is produced by the extended model of the configuration with permanent magnet flux bias.

  1. Comparison of the single channel and multichannel (multivariate) concepts of selectivity in analytical chemistry.

    PubMed

    Dorkó, Zsanett; Verbić, Tatjana; Horvai, George

    2015-07-01

    Different measures of selectivity are in use for single channel and multichannel linear analytical measurements, respectively. It is important to understand that these two measures express related but still distinctly different features of the respective measurements. These relationships are clarified by introducing new arguments. The most widely used selectivity measure of multichannel linear methods (which is based on the net analyte signal, NAS, concept) expresses the sensitivity to random errors of a determination where all bias from interferents is computationally eliminated using pure component spectra. The conventional selectivity measure of single channel linear measurements, on the other hand, helps to estimate the bias caused by an interferent in a biased measurement. In single channel methods expert knowledge about the samples is used to limit the possible range of interferent concentrations. The same kind of expert knowledge allows improved (lower mean squared error, MSE) analyte determinations also in "classical" multichannel measurements if those are intractable due to perfect collinearity or to high noise inflation. To achieve this goal bias variance tradeoff is employed, hence there remains some bias in the results and therefore the concept of single channel selectivity can be extended in a natural way to multichannel measurements. This extended definition and the resulting selectivity measure can also be applied to the so-called inverse multivariate methods like partial least squares regression (PLSR), principal component regression (PCR) and ridge regression (RR).

  2. A comparison of numerical simulations and analytical theory of the dynamics of interacting magnetic vortices

    SciTech Connect

    Asmat-Uceda, Martin; Buchanan, Kristen S.; Cheng, Xuemei; Wang, Xiao; Clarke, David J.; Tchernyshyov, Oleg

    2015-03-28

    Magnetostatic interactions between vortices in closely spaced planar structures are important for applications including vortex-based magnonic crystals and spin torque oscillator networks. Analytical theories that include magnetostatic interaction effects have been proposed but have not yet been rigorously tested. Here, we compare micromagnetic simulations of the dynamics of magnetic vortices confined in three disks in an equilateral triangle configuration to analytical theories that include coupling. Micromagnetic simulations show that the magnetostatic coupling between the disks leads to splitting of the gyrotropic resonance into three modes and that the frequency splitting increases with decreasing separation. The temporal profiles of the magnetization depend on the vortex polarities and chiralities; however, the frequencies depend only on the polarity combinations and will fall into one of two categories: all polarities equal or one polarity opposite to the others, where the latter leads to a larger frequency splitting. Although the magnitude of the splitting observed in the simulations is larger than what is expected based on purely dipolar interactions, a simple analytical model that assumes dipole-dipole coupling captures the functional form of the frequency splitting and the motion patterns just as well as more complex models.

  3. Electron-Vibrational Energy Exchange in Nitrogen-Containing Plasma: a Comparison Between an Analytical Approach and a Kinetic Model

    NASA Astrophysics Data System (ADS)

    Yang, Wei; Dong, Zhiwei

    2016-01-01

    This paper investigates the electron-vibrational (e-V) energy exchange in nitrogen-containing plasma, which is very efficient in the case of gas discharge and high speed flow. Based on Harmonic oscillator approximation and the assumption of the e-V relaxation through a continuous series of Boltzmann distributions over the vibrational states, an analytic approach is derived from the proposed scaling relation of e-V transition rates. A full kinetic model is then investigated by numerically solving the state-to-state master equation for all vibrational levels. The analytical approach leads to a Landau-Teller (LT)-type equation for relaxation of vibrational energy, and predicts the relaxation time on the right order of magnitude. By comparison with the kinetic model, the LT-type equation is valid in typical electron temperatures in gas discharge. However, the analytical approach is not capable of describing the vibrational distribution function during the e-V process in which a full kinetic model is required. supported by National Natural Science Foundation of China (No. 11505015) and the National High-Tech Research and Development Program of China (863 Program)

  4. Comparison of distance measures in spatial analytical modeling for health service planning

    PubMed Central

    2009-01-01

    Background Several methodological approaches have been used to estimate distance in health service research. In this study, focusing on cardiac catheterization services, Euclidean, Manhattan, and the less widely known Minkowski distance metrics are used to estimate distances from patient residence to hospital. Distance metrics typically produce less accurate estimates than actual measurements, but each metric provides a single model of travel over a given network. Therefore, distance metrics, unlike actual measurements, can be directly used in spatial analytical modeling. Euclidean distance is most often used, but unlikely the most appropriate metric. Minkowski distance is a more promising method. Distances estimated with each metric are contrasted with road distance and travel time measurements, and an optimized Minkowski distance is implemented in spatial analytical modeling. Methods Road distance and travel time are calculated from the postal code of residence of each patient undergoing cardiac catheterization to the pertinent hospital. The Minkowski metric is optimized, to approximate travel time and road distance, respectively. Distance estimates and distance measurements are then compared using descriptive statistics and visual mapping methods. The optimized Minkowski metric is implemented, via the spatial weight matrix, in a spatial regression model identifying socio-economic factors significantly associated with cardiac catheterization. Results The Minkowski coefficient that best approximates road distance is 1.54; 1.31 best approximates travel time. The latter is also a good predictor of road distance, thus providing the best single model of travel from patient's residence to hospital. The Euclidean metric and the optimal Minkowski metric are alternatively implemented in the regression model, and the results compared. The Minkowski method produces more reliable results than the traditional Euclidean metric. Conclusion Road distance and travel time

  5. Analysis of plant gums and saccharide materials in paint samples: comparison of GC-MS analytical procedures and databases

    PubMed Central

    2012-01-01

    Background Saccharide materials have been used for centuries as binding media, to paint, write and illuminate manuscripts and to apply metallic leaf decorations. Although the technical literature often reports on the use of plant gums as binders, actually several other saccharide materials can be encountered in paint samples, not only as major binders, but also as additives. In the literature, there are a variety of analytical procedures that utilize GC-MS to characterize saccharide materials in paint samples, however the chromatographic profiles are often extremely different and it is impossible to compare them and reliably identify the paint binder. Results This paper presents a comparison between two different analytical procedures based on GC-MS for the analysis of saccharide materials in works-of-art. The research presented here evaluates the influence of the analytical procedure used, and how it impacts the sugar profiles obtained from the analysis of paint samples that contain saccharide materials. The procedures have been developed, optimised and systematically used to characterise plant gums at the Getty Conservation Institute in Los Angeles, USA (GCI) and the Department of Chemistry and Industrial Chemistry of the University of Pisa, Italy (DCCI). The main steps of the analytical procedures and their optimisation are discussed. Conclusions The results presented highlight that the two methods give comparable sugar profiles, whether the samples analysed are simple raw materials, pigmented and unpigmented paint replicas, or paint samples collected from hundreds of centuries old polychrome art objects. A common database of sugar profiles of reference materials commonly found in paint samples was thus compiled. The database presents data also from those materials that only contain a minor saccharide fraction. This database highlights how many sources of saccharides can be found in a paint sample, representing an important step forward in the problem of

  6. Analysis of plant gums and saccharide materials in paint samples: comparison of GC-MS analytical procedures and databases.

    PubMed

    Lluveras-Tenorio, Anna; Mazurek, Joy; Restivo, Annalaura; Colombini, Maria Perla; Bonaduce, Ilaria

    2012-10-10

    Saccharide materials have been used for centuries as binding media, to paint, write and illuminate manuscripts and to apply metallic leaf decorations. Although the technical literature often reports on the use of plant gums as binders, actually several other saccharide materials can be encountered in paint samples, not only as major binders, but also as additives. In the literature, there are a variety of analytical procedures that utilize GC-MS to characterize saccharide materials in paint samples, however the chromatographic profiles are often extremely different and it is impossible to compare them and reliably identify the paint binder. This paper presents a comparison between two different analytical procedures based on GC-MS for the analysis of saccharide materials in works-of-art. The research presented here evaluates the influence of the analytical procedure used, and how it impacts the sugar profiles obtained from the analysis of paint samples that contain saccharide materials. The procedures have been developed, optimised and systematically used to characterise plant gums at the Getty Conservation Institute in Los Angeles, USA (GCI) and the Department of Chemistry and Industrial Chemistry of the University of Pisa, Italy (DCCI). The main steps of the analytical procedures and their optimisation are discussed. The results presented highlight that the two methods give comparable sugar profiles, whether the samples analysed are simple raw materials, pigmented and unpigmented paint replicas, or paint samples collected from hundreds of centuries old polychrome art objects. A common database of sugar profiles of reference materials commonly found in paint samples was thus compiled. The database presents data also from those materials that only contain a minor saccharide fraction. This database highlights how many sources of saccharides can be found in a paint sample, representing an important step forward in the problem of identifying polysaccharide binders in

  7. A comparison of analytical and numerical models for steadily driven magnetic reconnection

    NASA Technical Reports Server (NTRS)

    Forbes, T. G.; Priest, E. R.

    1987-01-01

    The effect of boundary conditions in both analytical and numerical solutions of steadily driven reconnection on the reconnection of antiparallel magnetic fields is considered, with special attention given to the mathematical problem of properly specifying boundary conditions for the MHD equation. A unified formulation developed by Priest and Forbes (1986) for steady state reconnection, which includes the Petschek solution and the Sonnerup (1970) solution as special cases, is used to reinterpret the previous numerical experiments of steadily driven reconnection. It is shown that many contradictory features of these experiments were caused by the use of boundary conditions which are different from those required by Petschek's (1964) theory.

  8. Comparison of three sampling and analytical methods for the determination of airborne hexavalent chromium.

    PubMed

    Boiano, J M; Wallace, M E; Sieber, W K; Groff, J H; Wang, J; Ashley, K

    2000-08-01

    A field study was conducted with the goal of comparing the performance of three recently developed or modified sampling and analytical methods for the determination of airborne hexavalent chromium (Cr(VI)). The study was carried out in a hard chrome electroplating facility and in a jet engine manufacturing facility where airborne Cr(VI) was expected to be present. The analytical methods evaluated included two laboratory-based procedures (OSHA Method ID-215 and NIOSH Method 7605) and a field-portable method (NIOSH Method 7703). These three methods employ an identical sampling methodology: collection of Cr(VI)-containing aerosol on a polyvinyl chloride (PVC) filter housed in a sampling cassette, which is connected to a personal sampling pump calibrated at an appropriate flow rate. The basis of the analytical methods for all three methods involves extraction of the PVC filter in alkaline buffer solution, chemical isolation of the Cr(VI) ion, complexation of the Cr(VI) ion with 1,5-diphenylcarbazide, and spectrometric measurement of the violet chromium diphenylcarbazone complex at 540 nm. However, there are notable specific differences within the sample preparation procedures used in three methods. To assess the comparability of the three measurement protocols, a total of 20 side-by-side air samples were collected, equally divided between a chromic acid electroplating operation and a spray paint operation where water soluble forms of Cr(VI) were used. A range of Cr(VI) concentrations from 0.6 to 960 microg m(-3), with Cr(VI) mass loadings ranging from 0.4 to 32 microg, was measured at the two operations. The equivalence of the means of the log-transformed Cr(VI) concentrations obtained from the different analytical methods was compared. Based on analysis of variance (ANOVA) results, no statistically significant differences were observed between mean values measured using each of the three methods. Small but statistically significant differences were observed between

  9. Deceleration of CMEs in the interplanetary medium: comparison of different analytic models

    NASA Astrophysics Data System (ADS)

    Corona-Romero, P.; Gonzalez-Esparza, A.

    2011-12-01

    We study the evolution of fast CMEs from near the Sun to 1 AU. There are several analytic models to describe the CME's propagation and to predict the 1 AU transit times and arrival velocities. In this work we compare the drag force (Vrsnak & Gopalswamy [2002], Cargill [2004]), mass piling up (Canto et al. [2005], Tappin [2006]) and viscous and turbulent force (Borgazzi et al. [2009]) deceleration models. We present a few study cases applying the different models and comparing the results with observations. We discuss the similarities and differences between the models.

  10. Comparison of Experimental and Analytical Tooth Bending Stress of Aerospace Spiral Bevel Gears

    DTIC Science & Technology

    1999-02-01

    location. These stress values were found for the output torque on the gear equaling 1073 N*m (9500 in*lb). B - Experimental Results. Testing was... 1073 N*m (9500 in*lb) of gear shaft torque. Note that the results are the same with respect to relative magnitudes between the regions of the fillet as...torque equal to 1073 N*m (9500 in*lb) at a pinion rotational speed equal to 14400 RPM. The analytical results were taken for the mid-face results from

  11. Comparison of Numeric to Analytic Solutions for a Class of Nonlinear Diffusion Equations

    SciTech Connect

    Knapp, Charles E.; Cranfill, Charles W.

    1992-10-23

    In order to test the accuracy of numerical algorithms for solving nonlinear diffusion equations, self-similar analytic solutions to a class of such equations have been constructed using Lie group techniques. The diffusion equations treated have the form δtk = 'δx(g'knδxk), where δt and δx represent partial derivatives with respect to time and position, k is the diffusing quantity, n is the nonlinearity parameter, and g is a general scaling constant. A standard time-implicit finite-difference diffusion algorithm is shown to give excellent agreement with the analytic solutions if the time and position step sizes are sufficiently small. In particular, an automatic time-step control which limits the fractional change ink produces quite good results. Examples are presented using several fixed time and position step sizes for four values of the nonlinearity parameter (n = 1/2,1, 3/2, 2) and using the automatic time-step control for three values (n = 1/2, 1, 3/2).

  12. Analytical and experimental comparisons of electromechanical vibration response of a piezoelectric bimorph beam for power harvesting

    NASA Astrophysics Data System (ADS)

    Lumentut, M. F.; Howard, I. M.

    2013-03-01

    Power harvesters that extract energy from vibrating systems via piezoelectric transduction show strong potential for powering smart wireless sensor devices in applications of health condition monitoring of rotating machinery and structures. This paper presents an analytical method for modelling an electromechanical piezoelectric bimorph beam with tip mass under two input base transverse and longitudinal excitations. The Euler-Bernoulli beam equations were used to model the piezoelectric bimorph beam. The polarity-electric field of the piezoelectric element is excited by the strain field caused by base input excitation, resulting in electrical charge. The governing electromechanical dynamic equations were derived analytically using the weak form of the Hamiltonian principle to obtain the constitutive equations. Three constitutive electromechanical dynamic equations based on independent coefficients of virtual displacement vectors were formulated and then further modelled using the normalised Ritz eigenfunction series. The electromechanical formulations include both the series and parallel connections of the piezoelectric bimorph. The multi-mode frequency response functions (FRFs) under varying electrical load resistance were formulated using Laplace transformation for the multi-input mechanical vibrations to provide the multi-output dynamic displacement, velocity, voltage, current and power. The experimental and theoretical validations reduced for the single mode system were shown to provide reasonable predictions. The model results from polar base excitation for off-axis input motions were validated with experimental results showing the change to the electrical power frequency response amplitude as a function of excitation angle, with relevance for practical implementation.

  13. Electron Beam Return-Current Losses in Solar Flares: Initial Comparison of Analytical and Numerical Results

    NASA Technical Reports Server (NTRS)

    Holman, Gordon

    2010-01-01

    Accelerated electrons play an important role in the energetics of solar flares. Understanding the process or processes that accelerate these electrons to high, nonthermal energies also depends on understanding the evolution of these electrons between the acceleration region and the region where they are observed through their hard X-ray or radio emission. Energy losses in the co-spatial electric field that drives the current-neutralizing return current can flatten the electron distribution toward low energies. This in turn flattens the corresponding bremsstrahlung hard X-ray spectrum toward low energies. The lost electron beam energy also enhances heating in the coronal part of the flare loop. Extending earlier work by Knight & Sturrock (1977), Emslie (1980), Diakonov & Somov (1988), and Litvinenko & Somov (1991), I have derived analytical and semi-analytical results for the nonthermal electron distribution function and the self-consistent electric field strength in the presence of a steady-state return-current. I review these results, presented previously at the 2009 SPD Meeting in Boulder, CO, and compare them and computed X-ray spectra with numerical results obtained by Zharkova & Gordovskii (2005, 2006). The phYSical significance of similarities and differences in the results will be emphasized. This work is supported by NASA's Heliophysics Guest Investigator Program and the RHESSI Project.

  14. Comparison of FDTD numerical computations and analytical multipole expansion method for plasmonics-active nanosphere dimers.

    PubMed

    Dhawan, Anuj; Norton, Stephen J; Gerhold, Michael D; Vo-Dinh, Tuan

    2009-06-08

    This paper describes a comparative study of finite-difference time-domain (FDTD) and analytical evaluations of electromagnetic fields in the vicinity of dimers of metallic nanospheres of plasmonics-active metals. The results of these two computational methods, to determine electromagnetic field enhancement in the region often referred to as "hot spots" between the two nanospheres forming the dimer, were compared and a strong correlation observed for gold dimers. The analytical evaluation involved the use of the spherical-harmonic addition theorem to relate the multipole expansion coefficients between the two nanospheres. In these evaluations, the spacing between two nanospheres forming the dimer was varied to obtain the effect of nanoparticle spacing on the electromagnetic fields in the regions between the nanostructures. Gold and silver were the metals investigated in our work as they exhibit substantial plasmon resonance properties in the ultraviolet, visible, and near-infrared spectral regimes. The results indicate excellent correlation between the two computational methods, especially for gold nanosphere dimers with only a 5-10% difference between the two methods. The effect of varying the diameters of the nanospheres forming the dimer, on the electromagnetic field enhancement, was also studied.

  15. Cerebellar areas dedicated to social cognition? A comparison of meta-analytic and connectivity results.

    PubMed

    Van Overwalle, Frank; Baetens, Kris; Mariën, Peter; Vandekerckhove, Marie

    2015-08-01

    A recent meta-analysis explored the role of the cerebellum in social cognition and documented that this part of the brain is critically implicated in social cognition, especially in more abstract and complex forms of mentalizing. The authors found an overlap with clusters involved in sensorimotor (during mirror and self-judgment tasks) as well as in executive processes (across all tasks) documented in earlier nonsocial cerebellar meta-analyses, and hence interpreted their results in terms of a domain-general function of the cerebellum. However, these meta-analytic results might be interpreted in a different, complementary way. Indeed, the results reveal a striking overlap with the parcellation of cerebellar topography offered by a recent functional connectivity analysis. In particular, the majority of social cognitive activity in the cerebellum can also be explained as located within the boundaries of a default/mentalizing network of the cerebellum, with the exception of the involvement of primary and integrative somatomotor networks for self-related and mirror tasks, respectively. Given the substantial overlap, a novel interpretation of the meta-analytic findings is put forward suggesting that cerebellar activity during social judgments might reflect a more domain-specific mentalizing functionality in some areas of the cerebellum than assumed before.

  16. Electron Beam Return-Current Losses in Solar Flares: Initial Comparison of Analytical and Numerical Results

    NASA Technical Reports Server (NTRS)

    Holman, Gordon

    2010-01-01

    Accelerated electrons play an important role in the energetics of solar flares. Understanding the process or processes that accelerate these electrons to high, nonthermal energies also depends on understanding the evolution of these electrons between the acceleration region and the region where they are observed through their hard X-ray or radio emission. Energy losses in the co-spatial electric field that drives the current-neutralizing return current can flatten the electron distribution toward low energies. This in turn flattens the corresponding bremsstrahlung hard X-ray spectrum toward low energies. The lost electron beam energy also enhances heating in the coronal part of the flare loop. Extending earlier work by Knight & Sturrock (1977), Emslie (1980), Diakonov & Somov (1988), and Litvinenko & Somov (1991), I have derived analytical and semi-analytical results for the nonthermal electron distribution function and the self-consistent electric field strength in the presence of a steady-state return-current. I review these results, presented previously at the 2009 SPD Meeting in Boulder, CO, and compare them and computed X-ray spectra with numerical results obtained by Zharkova & Gordovskii (2005, 2006). The phYSical significance of similarities and differences in the results will be emphasized. This work is supported by NASA's Heliophysics Guest Investigator Program and the RHESSI Project.

  17. Comparison of ISS Power System Telemetry with Analytically Derived Data for Shadowed Cases

    NASA Technical Reports Server (NTRS)

    Fincannon, H. James

    2002-01-01

    Accurate International Space Station (ISS) power prediction requires the quantification of solar array shadowing. Prior papers have discussed the NASA Glenn Research Center (GRC) ISS power system tool SPACE (System Power Analysis for Capability Evaluation) and its integrated shadowing algorithms. On-orbit telemetry has become available that permits the correlation of theoretical shadowing predictions with actual data. This paper documents the comparison of a shadowing metric (total solar array current) as derived from SPACE predictions and on-orbit flight telemetry data for representative significant shadowing cases. Images from flight video recordings and the SPACE computer program graphical output are used to illustrate the comparison. The accuracy of the SPACE shadowing capability is demonstrated for the cases examined.

  18. Technical Evaluation Motor No. 7 (TEM-7)

    NASA Technical Reports Server (NTRS)

    Hughes, Phil

    1991-01-01

    The Technical Evaluation Motor No. 7 (TEM-7) test was a full-scale, full duration static test firing of a high performance motor-configuration solid rocket motor with nozzle vectoring. The final test report documents the procedures, performance, and results of the static test firing of TEM-7. All observations, discussions, conclusions, and recommendations included in the report are complete and final except for the TEM-7 fixed housing unbond investigation. A presentation and discussion of TEM-7 performance, anomalies, and test result concurrence with the objectives outlined in CTP-0107, Rev A, Space Shuttle Technical Evaluation Motor No. 7 (TEM-7) Static Fire Test Plan are included.

  19. A Comparison of Analytical and Data Preprocessing Methods for Spectral Fingerprinting

    PubMed Central

    LUTHRIA, DEVANAND L.; MUKHOPADHYAY, SUDARSAN; LIN, LONG-ZE; HARNLY, JAMES M.

    2013-01-01

    Spectral fingerprinting, as a method of discriminating between plant cultivars and growing treatments for a common set of broccoli samples, was compared for six analytical instruments. Spectra were acquired for finely powdered solid samples using Fourier transform infrared (FT-IR) and Fourier transform near-infrared (NIR) spectrometry. Spectra were also acquired for unfractionated aqueous methanol extracts of the powders using molecular absorption in the ultraviolet (UV) and visible (VIS) regions and mass spectrometry with negative (MS−) and positive (MS+) ionization. The spectra were analyzed using nested one-way analysis of variance (ANOVA) and principal component analysis (PCA) to statistically evaluate the quality of discrimination. All six methods showed statistically significant differences between the cultivars and treatments. The significance of the statistical tests was improved by the judicious selection of spectral regions (IR and NIR), masses (MS+ and MS−), and derivatives (IR, NIR, UV, and VIS). PMID:21352644

  20. Monitoring environmental risk in fibrous minerals in New Caledonia: a comparison between different analytical methods.

    NASA Astrophysics Data System (ADS)

    Petriglieri, Jasmine Rita; Laporte-Magoni, Christine; Salvioli-Mariani, Emma; Gunkel-Grillon, Peggy; Tribaudino, Mario; Mantovani, Luciana; Bersani, Danilo; Lottici, Pier Paolo; Tomatis, Maura

    2017-04-01

    The New Caledonia is covered by ultrabasic units for more than a third of its surface, and it is one of the largest world producers of nickel ore. Mining activity, focused on extraction from lateritic ore deposits formed by the alteration of ultramafic rocks, must deal with the natural occurrence of asbestos and fibrous minerals. Almost all outcrops of geological units in open mines contain serpentine and amphibole, also as asbestos varieties (Lahondère, 2007). Owing to humid tropical to sub-tropical conditions, weathering processes and supergene mineralization are one of the main responsible for fibrogenesis of asbestos minerals. The presence of fibrous minerals in mining and storage sites requires attention due to public health problems and for the safety of the operators. In this context, the evaluation of risk and health hazard to prevent the effects due to exposition is closely linked to the formation, alteration and release of fibers into the environment. It has been demonstrated that different fibrous minerals have different toxicity (Fubini & Otero-Arean, 1999; Fubini & Fenoglio, 2007). An analytical strategy to discriminate and characterize, with certainty, the different varieties of the asbestiform phases is required to the establishment of an environmental monitoring system. We have therefore analyzed by different methods a set of about fifty asbestos sampled for mapping environmental risk in fibrous minerals in New Caledonia. The samples contain serpentines (chrysotile, antigorite) and amphibole (tremolite), all fibrous and have been sorted by their different degree of alteration. Data obtained with the more traditional mineralogical and petrological analytical techniques - such as optical microscopy, X-ray diffraction, secondary electron microscopy (SEM-EDS), and transmission electron microscopy - have been completed by the employment of more specialized tools as phase contrast microscopy (PCM), Raman spectroscopy, and thermal analysis (DTA). Moreover

  1. Determination of proline in honey: comparison between official methods, optimization and validation of the analytical methodology.

    PubMed

    Truzzi, Cristina; Annibaldi, Anna; Illuminati, Silvia; Finale, Carolina; Scarponi, Giuseppe

    2014-05-01

    The study compares official spectrophotometric methods for the determination of proline content in honey - those of the International Honey Commission (IHC) and the Association of Official Analytical Chemists (AOAC) - with the original Ough method. Results show that the extra time-consuming treatment stages added by the IHC method with respect to the Ough method are pointless. We demonstrate that the AOACs method proves to be the best in terms of accuracy and time saving. The optimized waiting time for the absorbance recording is set at 35min from the removal of reaction tubes from the boiling bath used in the sample treatment. The optimized method was validated in the matrix: linearity up to 1800mgL(-1), limit of detection 20mgL(-1), limit of quantification 61mgL(-1). The method was applied to 43 unifloral honey samples from the Marche region, Italy.

  2. Dynamics of Tachyon Fields and Inflation - Comparison of Analytical and Numerical Results with Observation

    NASA Astrophysics Data System (ADS)

    Milošević, M.; Dimitrijević, D. D.; Djordjević, G. S.; Stojanović, M. D.

    2016-06-01

    The role tachyon fields may play in evolution of early universe is discussed in this paper. We consider the evolution of a flat and homogeneous universe governed by a tachyon scalar field with the DBI-type action and calculate the slow-roll parameters of inflation, scalar spectral index (n), and tensor-scalar ratio (r) for the given potentials. We pay special attention to the inverse power potential, first of all to V(x)˜ x^{-4}, and compare the available results obtained by analytical and numerical methods with those obtained by observation. It is shown that the computed values of the observational parameters and the observed ones are in a good agreement for the high values of the constant X_0. The possibility that influence of the radion field can extend a range of the acceptable values of the constant X_0 to the string theory motivated sector of its values is briefly considered.

  3. Comparison of a two-dimensional adaptive-wall technique with analytical wall interference correction techniques

    NASA Technical Reports Server (NTRS)

    Mineck, Raymond E.

    1992-01-01

    A two dimensional airfoil model was tested in the adaptive wall test section of the NASA Langley 0.3 meter Transonic Cryogenic Tunnel (TCT) and in the ventilated test section of the National Aeronautical Establishment Two Dimensional High Reynold Number Facility (HRNF). The primary goal of the tests was to compare different techniques (adaptive test section walls and classical, analytical corrections) to account for wall interference. Tests were conducted over a Mach number range from 0.3 to 0.8 at chord Reynolds numbers of 10 x 10(exp 6), 15 x 10(exp 6), and 20 x 10(exp 6). The angle of attack was varied from about 12 degrees up to stall. Movement of the top and bottom test section walls was used to account for the wall interference in the HRNF tests. The test results are in good agreement.

  4. Shock compression modeling of metallic single crystals: comparison of finite difference, steady wave, and analytical solutions

    SciTech Connect

    Lloyd, Jeffrey T.; Clayton, John D.; Austin, Ryan A.; McDowell, David L.

    2015-07-10

    Background: The shock response of metallic single crystals can be captured using a micro-mechanical description of the thermoelastic-viscoplastic material response; however, using a such a description within the context of traditional numerical methods may introduce a physical artifacts. Advantages and disadvantages of complex material descriptions, in particular the viscoplastic response, must be framed within approximations introduced by numerical methods. Methods: Three methods of modeling the shock response of metallic single crystals are summarized: finite difference simulations, steady wave simulations, and algebraic solutions of the Rankine-Hugoniot jump conditions. For the former two numerical techniques, a dislocation density based framework describes the rate- and temperature-dependent shear strength on each slip system. For the latter analytical technique, a simple (two-parameter) rate- and temperature-independent linear hardening description is necessarily invoked to enable simultaneous solution of the governing equations. For all models, the same nonlinear thermoelastic energy potential incorporating elastic constants of up to order 3 is applied. Results: Solutions are compared for plate impact of highly symmetric orientations (all three methods) and low symmetry orientations (numerical methods only) of aluminum single crystals shocked to 5 GPa (weak shock regime) and 25 GPa (overdriven regime). Conclusions: For weak shocks, results of the two numerical methods are very similar, regardless of crystallographic orientation. For strong shocks, artificial viscosity affects the finite difference solution, and effects of transverse waves for the lower symmetry orientations not captured by the steady wave method become important. The analytical solution, which can only be applied to highly symmetric orientations, provides reasonable accuracy with regards to prediction of most variables in the final shocked state but, by construction, does not provide insight

  5. Shock compression modeling of metallic single crystals: comparison of finite difference, steady wave, and analytical solutions

    DOE PAGES

    Lloyd, Jeffrey T.; Clayton, John D.; Austin, Ryan A.; ...

    2015-07-10

    Background: The shock response of metallic single crystals can be captured using a micro-mechanical description of the thermoelastic-viscoplastic material response; however, using a such a description within the context of traditional numerical methods may introduce a physical artifacts. Advantages and disadvantages of complex material descriptions, in particular the viscoplastic response, must be framed within approximations introduced by numerical methods. Methods: Three methods of modeling the shock response of metallic single crystals are summarized: finite difference simulations, steady wave simulations, and algebraic solutions of the Rankine-Hugoniot jump conditions. For the former two numerical techniques, a dislocation density based framework describes themore » rate- and temperature-dependent shear strength on each slip system. For the latter analytical technique, a simple (two-parameter) rate- and temperature-independent linear hardening description is necessarily invoked to enable simultaneous solution of the governing equations. For all models, the same nonlinear thermoelastic energy potential incorporating elastic constants of up to order 3 is applied. Results: Solutions are compared for plate impact of highly symmetric orientations (all three methods) and low symmetry orientations (numerical methods only) of aluminum single crystals shocked to 5 GPa (weak shock regime) and 25 GPa (overdriven regime). Conclusions: For weak shocks, results of the two numerical methods are very similar, regardless of crystallographic orientation. For strong shocks, artificial viscosity affects the finite difference solution, and effects of transverse waves for the lower symmetry orientations not captured by the steady wave method become important. The analytical solution, which can only be applied to highly symmetric orientations, provides reasonable accuracy with regards to prediction of most variables in the final shocked state but, by construction, does not provide

  6. An analytical model of skin: comparison with experimental results in vivo

    NASA Astrophysics Data System (ADS)

    Woodward, Ruth M.

    2005-04-01

    Terahertz pulsed imaging is a non-invasive, non-ionizing imaging technique, using electromagnetic radiation defined in the frequency range 0.1 THz to 10 THz. Using reflection imaging systems with a frequency range 0.1 THz to 4 THz a far field diffraction limited lateral resolution of 3 mm to 110 microns is attainable. A three layer analytical model has been developed to simulate the hydration properties of skin in reflection. Earlier in vivo hydration measurements of the volar forearm and palm of the hand (thenar) are compared to this model. The time-domain analysis technique "time post pulse" (TPP) used to differentiate between diseased and normal tissue in a study of basal cell carcinoma was applied to the data. An increase in the value of TPP is observed with occlusion in the viable epidermis. This is attributed to an increase in the flux of water across the epidermis or dermis with increased stratum corneum hydration. This is verified by the literature. The change is observed in less than six minutes occlusion, making terahertz technology one of the most sensitive techniques for monitoring skin hydration levels. The contrast observed at the stratum corneum-viable epidermis interface is similar to that seen between diseased and normal tissue. Although water provides a good marker for studying diseased tissue, comparing results from DNA and protein analysis, it is not yet possible to conclude whether the contrast observed in basal cell carcinoma is due to increased water within the diseased tissue, a change in the vibrational modes of water with other functional groups, or a change in the vibrational modes of the functional groups alone. Further studies are required to determine whether terahertz technology is capable of differentiating between different histological subtypes in a collective system such as skin at a macroscopic level. The three layer analytical model provides a useful adjunct for identifying the source of contrast observed in the top surface of

  7. Default network activation during episodic and semantic memory retrieval: A selective meta-analytic comparison.

    PubMed

    Kim, Hongkeun

    2016-01-08

    It remains unclear whether and to what extent the default network subregions involved in episodic memory (EM) and semantic memory (SM) processes overlap or are separated from one another. This study addresses this issue through a controlled meta-analysis of functional neuroimaging studies involving healthy participants. Various EM and SM task paradigms differ widely in the extent of default network involvement. Therefore, the issue at hand cannot be properly addressed without some control for this factor. In this regard, this study employs a two-stage analysis: a preliminary meta-analysis to select EM and SM task paradigms that recruit relatively extensive default network regions and a main analysis to compare the selected task paradigms. Based on a within-EM comparison, the default network contributed more to recollection/familiarity effects than to old/new effects, and based on a within-SM comparison, it contributed more to word/pseudoword effects than to semantic/phonological effects. According to a direct comparison of recollection/familiarity and word/pseudoword effects, each involving a range of default network regions, there were more overlaps than separations in default network subregions involved in these two effects. More specifically, overlaps included the bilateral posterior cingulate/retrosplenial cortex, left inferior parietal lobule, and left anteromedial prefrontal regions, whereas separations included only the hippocampal formation and the parahippocampal cortex region, which was unique to recollection/familiarity effects. These results indicate that EM and SM retrieval processes involving strong memory signals recruit extensive and largely overlapping default network regions and differ mainly in distinct contributions of hippocampus and parahippocampal regions to EM retrieval.

  8. Visual Analytics for Comparison of Ocean Model Output with Reference Data: Detecting and Analyzing Geophysical Processes Using Clustering Ensembles.

    PubMed

    Köthur, Patrick; Sips, Mike; Dobslaw, Henryk; Dransch, Doris

    2014-12-01

    Researchers assess the quality of an ocean model by comparing its output to that of a previous model version or to observations. One objective of the comparison is to detect and to analyze differences and similarities between both data sets regarding geophysical processes, such as particular ocean currents. This task involves the analysis of thousands or hundreds of thousands of geographically referenced temporal profiles in the data. To cope with the amount of data, modelers combine aggregation of temporal profiles to single statistical values with visual comparison. Although this strategy is based on experience and a well-grounded body of expert knowledge, our discussions with domain experts have shown that it has two limitations: (1) using a single statistical measure results in a rather limited scope of the comparison and in significant loss of information, and (2) the decisions modelers have to make in the process may lead to important aspects being overlooked. In this article, we propose a Visual Analytics approach that broadens the scope of the analysis, reduces subjectivity, and facilitates comparison of the two data sets. It comprises three steps: First, it allows modelers to consider many aspects of the temporal behavior of geophysical processes by conducting multiple clusterings of the temporal profiles in each data set. Modelers can choose different features describing the temporal behavior of relevant processes, clustering algorithms, and parameterizations. Second, our approach consolidates the clusterings of one data set into a single clustering via a clustering ensembles approach. The consolidated clustering presents an overview of the geospatial distribution of temporal behavior in a data set. Third, a visual interface allows modelers to compare the two consolidated clusterings. It enables them to detect clusters of temporal profiles that represent geophysical processes and to analyze differences and similarities between two data sets. This work is

  9. Flight investigation of approach and flare from simulated breakout altitude of a subsonic jet transport and comparison with analytical models

    NASA Technical Reports Server (NTRS)

    Matheny, N. W.

    1974-01-01

    Satisfactory and optimum flare windows are defined from pilot ratings and comments. Maximum flare normal accelerations, touchdown rates of sink, and total landing maneuver time increments are summarized as a function of approach airspeed margin (with respect to reference airspeed) and flare initiation altitude. The effects of two thrust management techniques are investigated. Comparisons are made with predictions from three analytical models and the results of a simulator study. The approach speed margin was found to have a greater influence on the flare initiation altitude than the absolute airspeed. The optimum airspeed was between the reference airspeed and the reference airspeed plus 10 knots. The optimum flare initiation altitude range for unrestricted landings was from 11 meters to 20 meters (36 feet to 66 feet), and the landing time in the optimum window was 8 seconds. The duration of the landing maneuver increased with increasing flare initiation altitude and with increasing speed margins on the approach.

  10. Final report of the key comparison CCQM-K72: Purity of zinc with respect to six defined metallic analytes

    NASA Astrophysics Data System (ADS)

    Vogl, Jochen; Kipphardt, Heinrich; del Rocío Arvizu Torres, María; Manzano, Judith Velina Lara; Marques Rodrigues, Janaína; Caciano de Sena, Rodrigo; Yim, Yong-Hyeon; Heo, Sung Woo; Zhou, Tao; Turk, Gregory C.; Winchester, Michael; Yu, Lee L.; Miura, Tsutomu; Methven, B.; Sturgeon, Ralph; Jährling, Reinhard; Rienitz, Olaf; Tunç, Murat; Zühtü Can, Süleyman

    2014-01-01

    High purity elements can serve as a realization of the SI unit amount of substance for the specific element. Solutions prepared from high purity metals by applying gravimetric preparation and the concept of molar mass are used as 'calibration' solutions in many fields of analytical chemistry and provide the metrological basis in elemental analysis. Since ideal purity does not exist for real materials, the actual purity of the high purity material must be known with a specified uncertainty. As required uncertainties around 10-4 relative on the purity statement are not accessible in almost all cases by a direct measurement of the element in itself, the indirect approach is followed, where all elements excepting the matrix element itself are measured and their sum is subtracted from the value for ideal purity, which is 1 kg/kg. It was the aim of this comparison to demonstrate the capability of national metrology institutes and designated institutes to determine the purity of pure elements. In order to limit the effort within this comparison, only six metallic impurities (Ag, Al, Cd, Cr, Ni, Tl) in the low mg/kg range are considered in a zinc matrix. It has to be underlined here that the task was to measure the purity of zinc based on the determination of six analytes. The task is not trace analysis of specific analytes in zinc. This subtle distinction defines different measurands. The sample, pure Zn, was cut in pieces of cubic geometry for wet chemical analysis or of pin geometry for GDMS analysis and was sent to the participants. The comparison was run under the auspices of the Inorganic analysis Working Group (IAWG) of the CCQM and was piloted by the BAM Federal Institute for Materials Research and Testing, Berlin, Germany. The majority of the participants applied ICP-MS techniques and only two participants used additionally atomic absorption spectrometry. GDMS was used only by one participant. The observed spreads for the measurement results reported by the

  11. A comparison of observed and analytically derived remote sensing penetration depths for turbid water

    NASA Technical Reports Server (NTRS)

    Morris, W. D.; Usry, J. W.; Witte, W. G.; Whitlock, C. H.; Guraus, E. A.

    1981-01-01

    The depth to which sunlight will penetrate in turbid waters was investigated. The tests were conducted in water with a single scattering albedo range, and over a range of solar elevation angles. Two different techniques were used to determine the depth of light penetration. It showed little change in the depth of sunlight penetration with changing solar elevation angle. A comparison of the penetration depths indicates that the best agreement between the two methods was achieved when the quasisingle scattering relationship was not corrected for solar angle. It is concluded that sunlight penetration is dependent on inherent water properties only.

  12. An Evaluation of an Analytical Simulation of an Airplane with Tailplane Icing by Comparison to Flight Data

    NASA Technical Reports Server (NTRS)

    Hiltner, Dale W.

    2000-01-01

    This report presents the assessment of an analytical tool developed as part of the NASA/FAA Tailplane Icing Program. The analytical tool is a specialized simulation program called TAILSM4 which was developed to model the effects of tailplane icing on the flight dynamics Twin Otter Icing Research Aircraft. This report compares the responses of the TAILSIM program directly to flight test data. The comparisons should be useful to potential users of TAILSIM. The comparisons show that the TAILSIM program qualitatively duplicates the flight test aircraft response during maneuvers with ice on the tailplane. TAILSIM is shown to be quantitatively "in the ballpark" in predicting when Ice Contaminated Tailplane Stall will occur during pushover and thrust transition maneuvers. As such, TAILSIM proved its usefulness to the flight test program by providing a general indication of the aircraft configuration and flight conditions of concern. The aircraft dynamics are shown to be modeled correctly by the equations of motion used in TAILSIM. However, the general accuracy of the TAILSIM responses is shown to be less than desired primarily due to inaccuracies in the aircraft database. The high sensitivity of the TAILSIM program responses to small changes in load factor command input is also shown to be a factor in the accuracy of the responses. A pilot model is shown to allow TAILSIM to produce more accurate responses and contribute significantly to the usefulness of the program. Suggestions to improve the accuracy of the TAILSIM responses are to further refine the database representation of the aircraft aerodynamics and tailplane flowfield and to explore a more realistic definition of the pilot model.

  13. Comparison of Analytical Methods for the Determination of Uranium in Seawater Using Inductively Coupled Plasma Mass Spectrometry

    SciTech Connect

    Wood, Jordana R.; Gill, Gary A.; Kuo, Li-Jung; Strivens, Jonathan E.; Choe, Key-Young

    2016-04-20

    Trace element determinations in seawater by inductively coupled plasma mass spectrometry are analytically challenging due to the typically very low concentrations of the trace elements and the potential interference of the salt matrix. In this study, we did a comparison for uranium analysis using inductively coupled plasma mass spectrometry (ICP-MS) of Sequim Bay seawater samples and three seawater certified reference materials (SLEW-3, CASS-5 and NASS-6) using seven different analytical approaches. The methods evaluated include: direct analysis, Fe/Pd reductive precipitation, standard addition calibration, online automated dilution using an external calibration with and without matrix matching, and online automated pre-concentration. The method which produced the most accurate results was the method of standard addition calibration, recovering uranium from a Sequim Bay seawater sample at 101 ± 1.2%. The on-line preconcentration method and the automated dilution with matrix-matched calibration method also performed well. The two least effective methods were the direct analysis and the Fe/Pd reductive precipitation using sodium borohydride

  14. Comparison of behavior analytic and eclectic early interventions for young children with autism after three years.

    PubMed

    Howard, Jane S; Stanislaw, Harold; Green, Gina; Sparkman, Coleen R; Cohen, Howard G

    2014-12-01

    In a previous study, we compared the effects of just over one year of intensive behavior analytic intervention (IBT) provided to 29 young children diagnosed with autism with two eclectic (i.e., mixed-method) interventions (Howard, Sparkman, Cohen, Green, & Stanislaw, 2005). One eclectic intervention (autism programming; AP) was designed specifically for children with autism and was intensive in that it was delivered for an average of 25-30 h per week (n = 16). The other eclectic intervention (generic programming; GP) was delivered to 16 children with a variety of diagnoses and needs for an average of 15-17 h per week. This paper reports outcomes for children in all three groups after two additional years of intervention. With few exceptions, the benefits of IBT documented in our first study were sustained throughout Years 2 and 3. At their final assessment, children who received IBT were more than twice as likely to score in the normal range on measures of cognitive, language, and adaptive functioning than were children who received either form of eclectic intervention. Significantly more children in the IBT group than in the other two groups had IQ, language, and adaptive behavior test scores that increased by at least one standard deviation from intake to final assessment. Although the largest improvements for children in the IBT group generally occurred during Year 1, many children in that group whose scores were below the normal range after the first year of intervention attained scores in the normal range of functioning with one or two years of additional intervention. In contrast, children in the two eclectic treatment groups were unlikely to attain scores in the normal range after the first year of intervention, and many of those who had scores in the normal range in the first year fell out of the normal range in subsequent years. There were no consistent differences in outcomes at Years 2 and 3 between the two groups who received eclectic interventions

  15. Comparison of analytical and numerical particle deposition using commercial CFD packages: impaction and sedimentation.

    PubMed

    Robinson, Risa J; Snyder, Pamela; Oldham, Michael J

    2008-03-01

    Whole-lung dosimetry codes and computational fluid dynamics (CFD) techniques have been used extensively to predict particle deposition in the respiratory tract of animals and humans. Although these predictions implement three well-known deposition mechanisms (impaction, sedimentation, and diffusion), validation of deposition due to each deposition mechanism in isolation has been difficult. In the current work, impaction deposition predictions using equations from the leading whole-lung dosimetry codes were compared to experimental data for the same Stokes and Reynolds numbers. In addition, impaction was predicted numerically using two commercial CFD packages (CFX and Fluent) and compared to experimental particle deposition, for the same geometry, and flow conditions that were overwhelmingly impaction dominated as measured by the Stokes number. Significant differences were found between CFD predicted deposition due to impaction and the analytical equations contained in whole-lung dosimetry models (NCRP, Trumpet, MPPD). Of the two CFD software packages, CFX typically had the best agreement with the experimental data; however, neither software package agreed well for all Stokes numbers examined. In addition, predicted impaction deposition from whole-lung dosimetry code equations did not agree well with experimental data for all Stokes numbers. These discrepancies highlight the current state of uncertainty in particle deposition predictions and indicate that any single technique or equation may be unsuitable to accurately explain the flow and particle behavior in an airway bifurcation.

  16. Analysis of plasticizers in PVC medical devices: Performance comparison of eight analytical methods.

    PubMed

    Bernard, L; Bourdeaux, D; Pereira, B; Azaroual, N; Barthélémy, C; Breysse, C; Chennell, P; Cueff, R; Dine, T; Eljezi, T; Feutry, F; Genay, S; Kambia, N; Lecoeur, M; Masse, M; Odou, P; Radaniel, T; Simon, N; Vaccher, C; Verlhac, C; Yessad, M; Décaudin, B; Sautou, V

    2017-01-01

    A wide variety of medical devices (MDs) used in hospitals are made of flexible plasticized polyvinylchloride (PVC). Different plasticizers are present in variable amounts in the PVC matrix of the devices and can leach out into the infused solutions and may enter into contact with the patients. The ARMED(1) project aims to assess the migration of these plasticizers from medical devices and therefore the level of exposure in patients. For the first task of the project, eight methods were developed to directly detect and quantify the plasticizers in the PVC matrix of the MDs. We compared the overall performances of the analytical methods using standardized and validated criteria in order to provide the scientific community with the guidance and the technical specifications of each method for the intended application. We have shown that routine rapid screening could be performed directly on the MDs using the FTIR technique, with cost-effective analyses. LC techniques may also be used, but with limits and only with individual quantification of the main plasticizers expected in the PVC matrix. GC techniques, especially GC-MS, are both more specific and more sensitive than other techniques. NMR is a robust and specific technique to precisely discriminate all plasticizers in a MD but is limited by its cost and its low ability to detect and quantify plasticizer contamination, e.g. by DEHP. All these results have been confirmed by a real test, called the " blind test " carried out on 10 MD samples.

  17. Comparison of thyroid analytes in dogs aggressive to familiar people and in non-aggressive dogs.

    PubMed

    Radosta, Lisa A; Shofer, Frances S; Reisner, Ilana R

    2012-06-01

    A cross-sectional study was performed in order to examine the association between canine aggression to familiar people and serum concentrations of total thyroxine (TT4), free thyroxine (fT4), thyroxine autoantibodies (T4AA), total triiodothyronine (TT3), free triiodothyronine (fT3), triiodothyronine autoantibodies (T3AA), thyroid stimulating hormone (TSH), and thyroglobulin autoantibodies (TgAA). The subjects were 31 dogs historically aggressive to familiar people and 31 dogs with no history of aggression. Behavioral evaluation and physical examination were completed for each dog in addition to a complete blood count, serum chemistry panel, TT4, fT4 by equilibrium dialysis, TT3, fT3, TgAA, T3AA, and T4AA. Significant differences were found between the two groups with respect to only T4AA, which was increased in the aggressive group, but the concentrations for both groups were within the normal reference range. There were no differences between the two groups in the thyroid analytes most commonly measured by veterinary practitioners evaluating thyroid function in dogs. The results of this study revealed no significant difference between aggressive and non-aggressive dogs in the thyroid concentrations most commonly used to diagnose canine hypothyroidism.

  18. Comparison of limited measurements of the OTEC-1 plume with analytical-model predictions

    SciTech Connect

    Paddock, R.A.; Ditmars, J.D.

    1981-07-01

    Ocean Thermal Energy Conversion (OTEC) requires significant amounts of warm surface waters and cold deep waters for power production. Because these waters are returned to the ocean as effluents, their behavior may affect plant operation and impact the environment. The OTEC-1 facility tested 1-MWe heat exchangers aboard the vessel Ocean Energy Converter moored off the island of Hawaii. The warm and cold waters used by the OTEC-1 facility were combined prior to discharge from the vessel to create a mixed discharge condition. A limited field survey of the mixed discharge plume using fluorescent dye as a tracer was conducted on April 11, 1981, as part of the environmental studies at OTEC-1 coordinated by the Marine Sciences Group at Lawrence Berkeley Laboratory. Results of that survey were compared with analytical model predictions of plume behavior. Although the predictions were in general agreement with the results of the plume survey, inherent limitations in the field measurements precluded complete description of the plume or detailed evaluation of the models.

  19. Differential linear scan voltammetry: analytical performance in comparison with pulsed voltammetry techniques.

    PubMed

    Sheth, Disha B; Gratzl, Miklós

    2013-06-01

    We report here on differential linear scan voltammetry, DLSV, that combines the working principles of linear scan voltammetry, LSV, and the numerous existing pulsed voltammetry techniques. DLSV preserves the information from continuous interrogation in voltage and high accuracy that LSV provides about electrochemical processes, and the much better sensitivity of differential pulsed techniques. DLSV also minimizes the background current compared to both LSV and pulsed voltammetry. An early version of DLSV, derivative stationary electrode polarography, DSEP, had been proposed in the 1960s but soon abandoned in favor of the emerging differential pulsed techniques. Relative to DSEP, DLSV takes advantage of the flexibility of discrete smoothing differentiation that was not available to early investigators. Also, DSEP had been explored in pure solutions and with reversible electrochemical reactions. DLSV is tested in this work in more challenging experimental contexts: the measurement of oxygen with a carbon fiber microelectrode in buffer, and with a gold microdisc electrode exposed to a live biological preparation. This work compares the analytical performance of DLSV and square wave voltammetry, the most popular pulsed voltammetry technique.

  20. Comparison between different tests and their combination for prediction of difficult intubation: An analytical study

    PubMed Central

    Basunia, Sandip Roy; Ghosh, Sarmila; Bhattacharya, Susmita; Saha, Indranil; Biswas, Atanu; Prasad, Anu

    2013-01-01

    Context: There is an impelling need for accurate tests to predict difficult intubation, as failure to achieve endotracheal intubation causes significant morbidity and mortality in anesthetic practice. Aim: To calculate the validity of the different tests along with their combination and agreement when compared with endotracheal intubation in predicting difficult intubation. Settings and Design: Operation theaters, analytical study. Materials and Methods: Three hundred patients aged between 16 and 60 years of American society of anesthesiologist (ASA) physical status I and II, scheduled for elective surgical procedures requiring endotracheal intubation were studied during January-July 2012. Mallampati grade (MP), sternomental distance (SMD), thyromental distance (TMD), and Delilkan and Calder test were recorded for every patient. Endotracheal intubation was performed by an experienced anesthesiologist blinded to the measurements and recorded grading of intubation. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), likelihood ratio (LR), odds ratio (OR), and kappa coefficient of tests individually and in combination were calculated. Statistical Analysis Used: IBM SPSS software (version 16.0) and Epi-info software (version 3.2). Results: Difficult and failed intubation was 13.3% and 0.6%, respectively. Difficult intubation increased with age. TMD and Calder test showed highest sensitivity individually and Dellilkan's test showed least sensitivity. Among the combination of tests, MP with SMD and MP with Calder test had the highest sensitivity. Conclusion: Among individual test TMD and Calder are better predictive tests in terms of sensitivity. Combination of tests increases the chance of prediction of difficult intubation. PMID:25885730

  1. Quantification of camalexin, a phytoalexin from Arabidopsis thaliana: a comparison of five analytical methods.

    PubMed

    Beets, Caryn; Dubery, Ian

    2011-12-15

    Camalexin is a phytoalexin of Arabidopsis thaliana and an important component of inducible defenses. Accurate quantification of low concentrations suffers from interference by structurally related metabolites. A. thaliana plants were induced with silver nitrate and camalexin was extracted using methanol and identified and quantified by (i) TLC as a blue fluorescent band, (ii) microtiter plate-based fluorescence spectroscopy, (iii) GC on a midpolar column coupled to flame ionization detection, (iv) C(18) HPLC coupled to a photodiode detector, and (v) UPLC coupled to a mass spectrometer detector. Standard curves over the range of 0.1-15 μg ml(-1) gave R(2) values from 0.996 to 0.999. The different methods were compared and evaluated for their ability to detect and quantify increasing concentrations (<0.4-8 μgg(-1) FW) of camalexin. Each of the techniques presented advantages and disadvantages with regard to accuracy, precision, interference, analytical sensitivity, and limits of detection. TLC is a good qualitative technique for the identification of camalexin and fluorescence spectroscopy is subject to quenching when performed on crude extracts. Comparable results were obtained with GC-FID, HPLC-PDA, and UPLC-MS, with UPLC-MS having the added advantage of short analysis times and detection based on accurate mass. Copyright © 2011 Elsevier Inc. All rights reserved.

  2. Comparison of three prospective analytical methods for benzene analysis in jet-fuel environments. Final report

    SciTech Connect

    Hossain, M.A.

    1990-08-01

    Accurate analysis of benzene in jet fuel has been a concern over the past several years. The method we have been using to analyze benzene in jet fuel is the NIOSH 1501 method, a method specifically designed for aromatic hydrocarbons including benzene. However, the method is not designed for analysis of benzene in jet fuel environments. At the present time there is no approved (either by NIOSH or OSHA) method for analysis of benzene in fuel environments. At the request of HQ AAC/SGPB, we recently conducted a study to compare three prospective analytical methods (NIOSH method 1501 (GC/FID wtih packed column) modified NIOSH 1501 method (GC/FID with capillary column), and High Pressure Liquid Chromatography with Ultraviolet Detection (HPLC/UV)). In this study spiked charcoal tube samples as well as air samples of known concentrations of benzene in JP-4 and Stoddard Solvents were analyzed by all three methods. The test results showed that modified NIOSH 1501 and HPLC methods had good correlation between spiked and measured amount of benzene in JP-4 and Stoddard Solvent mixtures. The NIOSH 1501 method utilizing packed column over estimated the test benzene concentration indicating positive interference from other hydrocarbons present in JP 4 and Stoddard Solvents.

  3. Comparison of analytical methods for profiling N- and O-linked glycans from cultured cell lines

    PubMed Central

    Togayachi, Akira; Azadi, Parastoo; Ishihara, Mayumi; Geyer, Rudolf; Galuska, Christina; Geyer, Hildegard; Kakehi, Kazuaki; Kinoshita, Mitsuhiro; Karlsson, Niclas G.; Jin, Chunsheng; Kato, Koichi; Yagi, Hirokazu; Kondo, Sachiko; Kawasaki, Nana; Hashii, Noritaka; Kolarich, Daniel; Stavenhagen, Kathrin; Packer, Nicolle H.; Thaysen-Andersen, Morten; Nakano, Miyako; Taniguchi, Naoyuki; Kurimoto, Ayako; Wada, Yoshinao; Tajiri, Michiko; Yang, Pengyuan; Cao, Weiqian; Li, Hong; Rudd, Pauline M.; Narimatsu, Hisashi

    2016-01-01

    The Human Disease Glycomics/Proteome Initiative (HGPI) is an activity in the Human Proteome Organization (HUPO) supported by leading researchers from international institutes and aims at development of disease-related glycomics/glycoproteomics analysis techniques. Since 2004, the initiative has conducted three pilot studies. The first two were N- and O-glycan analyses of purified transferrin and immunoglobulin-G and assessed the most appropriate analytical approach employed at the time. This paper describes the third study, which was conducted to compare different approaches for quantitation of N- and O-linked glycans attached to proteins in crude biological samples. The preliminary analysis on cell pellets resulted in wildly varied glycan profiles, which was probably the consequence of variations in the pre-processing sample preparation methodologies. However, the reproducibility of the data was not improved dramatically in the subsequent analysis on cell lysate fractions prepared in a specified method by one lab. The study demonstrated the difficulty of carrying out a complete analysis of the glycome in crude samples by any single technology and the importance of rigorous optimization of the course of analysis from preprocessing to data interpretation. It suggests that another collaborative study employing the latest technologies in this rapidly evolving field will help to realize the requirements of carrying out the large-scale analysis of glycoproteins in complex cell samples. PMID:26511985

  4. Neutron noise calculations in a hexagonal geometry and comparison with analytical solutions

    SciTech Connect

    Tran, H. N.; Demaziere, C.

    2012-07-01

    This paper presents the development of a neutronic and kinetic solver for hexagonal geometries. The tool is developed based on the diffusion theory with multi-energy groups and multi-groups of delayed neutron precursors allowing the solutions of forward and adjoint problems of static and dynamic states, and is applicable to both thermal and fast systems with hexagonal geometries. In the dynamic problems, the small stationary fluctuations of macroscopic cross sections are considered as noise sources, and then the induced first order noise is calculated fully in the frequency domain. Numerical algorithms for solving the static and noise equations are implemented with a spatial discretization based on finite differences and a power iterative solution. A coarse mesh finite difference method has been adopted for speeding up the convergence. Since no other numerical tool could calculate frequency-dependent noise in hexagonal geometry, validation calculations have been performed and benchmarked to analytical solutions based on a 2-D homogeneous system with two-energy groups and one-group of delayed neutron precursor, in which point-like perturbations of thermal absorption cross section at central and non-central positions are considered as noise sources. (authors)

  5. Computational and analytical comparison of flux discretizations for the semiconductor device equations beyond Boltzmann statistics

    NASA Astrophysics Data System (ADS)

    Farrell, Patricio; Koprucki, Thomas; Fuhrmann, Jürgen

    2017-10-01

    We compare three thermodynamically consistent numerical fluxes known in the literature, appearing in a Voronoï finite volume discretization of the van Roosbroeck system with general charge carrier statistics. Our discussion includes an extension of the Scharfetter-Gummel scheme to non-Boltzmann (e.g. Fermi-Dirac) statistics. It is based on the analytical solution of a two-point boundary value problem obtained by projecting the continuous differential equation onto the interval between neighboring collocation points. Hence, it serves as a reference flux. The exact solution of the boundary value problem can be approximated by computationally cheaper fluxes which modify certain physical quantities. One alternative scheme averages the nonlinear diffusion (caused by the non-Boltzmann nature of the problem), another one modifies the effective density of states. To study the differences between these three schemes, we analyze the Taylor expansions, derive an error estimate, visualize the flux error and show how the schemes perform for a carefully designed p-i-n benchmark simulation. We present strong evidence that the flux discretization based on averaging the nonlinear diffusion has an edge over the scheme based on modifying the effective density of states.

  6. Comparison of patient preferences for fecal immunochemical test or colonoscopy using the analytic hierarchy process.

    PubMed

    Xu, Yinghui; Levy, Barcey T; Daly, Jeanette M; Bergus, George R; Dunkelberg, Jeffrey C

    2015-04-23

    In average-risk individuals aged 50 to 75 years, there is no difference in life-years gained when comparing colonoscopy every 10 years vs. annual fecal immunochemical testing (FIT) for colorectal cancer screening. Little is known about the preferences of patients when they have experienced both tests. The study was conducted with 954 patients from the University of Iowa Hospital and Clinics during 2010 to 2011. Patients scheduled for a colonoscopy were asked to complete a FIT before the colonoscopy preparation. Following both tests, patients completed a questionnaire which was based on an analytic hierarchy process (AHP) decision-making model. In the AHP analysis, the test accuracy was given the highest priority (0.457), followed by complications (0.321), and test preparation (0.223). Patients preferred colonoscopy (0.599) compared with FIT (0.401) when considering accuracy; preferred FIT (0.589) compared with colonoscopy (0.411) when considering avoiding complications; and preferred FIT (0.650) compared with colonoscopy (0.350) when considering test preparation. The overall aggregated priorities were 0.517 for FIT, and 0.483 for colonoscopy, indicating patients slightly preferred FIT over colonoscopy. Patients' preferences were significantly different before and after provision of detailed information on test features (p < 0.0001). AHP analysis showed that patients slightly preferred FIT over colonoscopy. The information provided to patients strongly affected patient preference. Patients' test preferences should be considered when ordering a colorectal cancer screening test.

  7. Oxygen-enriched diesel engine performance: A comparison of analytical and experimental results

    SciTech Connect

    Sekar, R.R.; Marr, W.W.; Cole, R.L.; Marciniak, T.J. ); Assanis, D.N. ); Schaus, J.E. )

    1990-01-01

    Use of oxygen-enriched combustion air in diesel engines can lead to significant improvements in power density, as well as reductions in particulate emissions, but at the expense of higher NO{sub x} emissions. Oxygen enrichment would also lead to lower ignition delays and the opportunity to burn lower grade fuels. Analytical and experimental studies are being conducted in parallel to establish the optimal combination of oxygen level and diesel fuel properties. In this paper, cylinder pressure data acquired on a single-cylinder engine are used to generate heat release rates for operation under various oxygen contents. These derived heat release rates are in turn used to improve the combustion correlation -- and thus the prediction capability -- of the simulation code. It is shown that simulated and measured cylinder pressures and other performance parameters are in good agreement. The improved simulation can provide sufficiently accurate predictions of trends and magnitudes to be useful in parametric studies assessing the effects of oxygen enrichment and water injection on diesel engine performance. Measured ignition delays, NO{sub x} emissions, and particulate emissions are also compared with previously published data. The measured ignition delays are slightly lower than previously reported. Particulate emissions measured in this series of tests are significantly lower than previously reported. 14 refs., 10 figs., 1 tab.

  8. Comparison of analytical tools and biological assays for detection of paralytic shellfish poisoning toxins.

    PubMed

    Humpage, A R; Magalhaes, V F; Froscio, S M

    2010-07-01

    The paralytic shellfish poisoning toxins (PSTs) were, as their name suggests, discovered as a result of human poisoning after consumption of contaminated shellfish. More recently, however, the same toxins have been found to be produced by freshwater cyanobacteria. These organisms have worldwide distribution and are common in our sources of drinking water, thus presenting another route of potential human exposure. However, the regulatory limits for PSTs in drinking water are considerably lower than in shellfish. This has increased the need to find alternatives to the mouse bioassay, which, apart from being ethically questionable, does not have a limit of detection capable of detecting the PSTs in water at the regulated concentrations. Additionally, the number of naturally occurring PSTs has grown substantially since saxitoxin was first characterised, markedly increasing the analytical challenge of this group of compounds. This paper summarises the development of chromatographic, toxicity, and molecular sensor binding methodologies for detection of the PSTs in shellfish, cyanobacteria, and water contaminated by these toxins. It then summarises the advantages and disadvantages of their use for particular applications. Finally it recommends some future requirements that will contribute to their improvement for these applications.

  9. Estimating estuarine salt intrusion using an analytical and a full hydrodynamic simulation - a comparison for the Ma Estuary

    NASA Astrophysics Data System (ADS)

    Nguyen, Duc Anh; Cat Vu, Minh; Willems, Patrick; Monbaliu, Jaak

    2017-04-01

    Salt intrusion is the most acute problem for irrigation water quality in coastal regions during dry seasons. The use of numerical hydrodynamic models is widespread and has become the prevailing approach to simulate the salinity distribution in an estuary. Despite its power to estimate both spatial and temporal salinity variations along the estuary, this approach also has its drawbacks. The high computational cost and the need for detailed hydrological, bathymetric and tidal datasets, put some limits on the usability in particular case studies. In poor data environments, analytical salt intrusion models are more widely used as they require less data and have a further reduction of the computational effort. There are few studies however where a more comprehensive comparison is made between the performance of a numerical hydrodynamic and an analytical model. In this research the multi-channel Ma Estuary in Vietnam is considered as a case study. Both the analytical and the hydrodynamic simulation approaches have been applied and were found capable to mimic the longitudinal salt distribution along the estuary. The data to construct the MIKE11 model include observations provided by a network of fixed hydrological stations and the cross-section measurements along the estuary. The analytic model is developed in parallel but based on information obtained from the hydrological network only (typical for poor data environment). Note that the two convergence length parameters of this simplified model are usually extracted from topography data including cross-sectional area and width along the estuary. Furthermore, freshwater discharge data are needed but these are gauged further upstream outside of the tidal region and unable to reflect the individual flows entering the multi-channel estuary. In order to tackle the poor data environment limitations, a new approach was needed to calibrate the two estuary geometry parameters of the parsimonious salt intrusion model. Compared to

  10. A Multilaboratory Comparison of Calibration Accuracy and the Performance of External References in Analytical Ultracentrifugation

    PubMed Central

    Zhao, Huaying; Ghirlando, Rodolfo; Alfonso, Carlos; Arisaka, Fumio; Attali, Ilan; Bain, David L.; Bakhtina, Marina M.; Becker, Donald F.; Bedwell, Gregory J.; Bekdemir, Ahmet; Besong, Tabot M. D.; Birck, Catherine; Brautigam, Chad A.; Brennerman, William; Byron, Olwyn; Bzowska, Agnieszka; Chaires, Jonathan B.; Chaton, Catherine T.; Cölfen, Helmut; Connaghan, Keith D.; Crowley, Kimberly A.; Curth, Ute; Daviter, Tina; Dean, William L.; Díez, Ana I.; Ebel, Christine; Eckert, Debra M.; Eisele, Leslie E.; Eisenstein, Edward; England, Patrick; Escalante, Carlos; Fagan, Jeffrey A.; Fairman, Robert; Finn, Ron M.; Fischle, Wolfgang; de la Torre, José García; Gor, Jayesh; Gustafsson, Henning; Hall, Damien; Harding, Stephen E.; Cifre, José G. Hernández; Herr, Andrew B.; Howell, Elizabeth E.; Isaac, Richard S.; Jao, Shu-Chuan; Jose, Davis; Kim, Soon-Jong; Kokona, Bashkim; Kornblatt, Jack A.; Kosek, Dalibor; Krayukhina, Elena; Krzizike, Daniel; Kusznir, Eric A.; Kwon, Hyewon; Larson, Adam; Laue, Thomas M.; Le Roy, Aline; Leech, Andrew P.; Lilie, Hauke; Luger, Karolin; Luque-Ortega, Juan R.; Ma, Jia; May, Carrie A.; Maynard, Ernest L.; Modrak-Wojcik, Anna; Mok, Yee-Foong; Mücke, Norbert; Nagel-Steger, Luitgard; Narlikar, Geeta J.; Noda, Masanori; Nourse, Amanda; Obsil, Tomas; Park, Chad K.; Park, Jin-Ku; Pawelek, Peter D.; Perdue, Erby E.; Perkins, Stephen J.; Perugini, Matthew A.; Peterson, Craig L.; Peverelli, Martin G.; Piszczek, Grzegorz; Prag, Gali; Prevelige, Peter E.; Raynal, Bertrand D. E.; Rezabkova, Lenka; Richter, Klaus; Ringel, Alison E.; Rosenberg, Rose; Rowe, Arthur J.; Rufer, Arne C.; Scott, David J.; Seravalli, Javier G.; Solovyova, Alexandra S.; Song, Renjie; Staunton, David; Stoddard, Caitlin; Stott, Katherine; Strauss, Holger M.; Streicher, Werner W.; Sumida, John P.; Swygert, Sarah G.; Szczepanowski, Roman H.; Tessmer, Ingrid; Toth, Ronald T.; Tripathy, Ashutosh; Uchiyama, Susumu; Uebel, Stephan F. W.; Unzai, Satoru; Gruber, Anna Vitlin; von Hippel, Peter H.; Wandrey, Christine; Wang, Szu-Huan; Weitzel, Steven E.; Wielgus-Kutrowska, Beata; Wolberger, Cynthia; Wolff, Martin; Wright, Edward; Wu, Yu-Sung; Wubben, Jacinta M.; Schuck, Peter

    2015-01-01

    Analytical ultracentrifugation (AUC) is a first principles based method to determine absolute sedimentation coefficients and buoyant molar masses of macromolecules and their complexes, reporting on their size and shape in free solution. The purpose of this multi-laboratory study was to establish the precision and accuracy of basic data dimensions in AUC and validate previously proposed calibration techniques. Three kits of AUC cell assemblies containing radial and temperature calibration tools and a bovine serum albumin (BSA) reference sample were shared among 67 laboratories, generating 129 comprehensive data sets. These allowed for an assessment of many parameters of instrument performance, including accuracy of the reported scan time after the start of centrifugation, the accuracy of the temperature calibration, and the accuracy of the radial magnification. The range of sedimentation coefficients obtained for BSA monomer in different instruments and using different optical systems was from 3.655 S to 4.949 S, with a mean and standard deviation of (4.304 ± 0.188) S (4.4%). After the combined application of correction factors derived from the external calibration references for elapsed time, scan velocity, temperature, and radial magnification, the range of s-values was reduced 7-fold with a mean of 4.325 S and a 6-fold reduced standard deviation of ± 0.030 S (0.7%). In addition, the large data set provided an opportunity to determine the instrument-to-instrument variation of the absolute radial positions reported in the scan files, the precision of photometric or refractometric signal magnitudes, and the precision of the calculated apparent molar mass of BSA monomer and the fraction of BSA dimers. These results highlight the necessity and effectiveness of independent calibration of basic AUC data dimensions for reliable quantitative studies. PMID:25997164

  11. Analysis of hydroponic fertilizer matrixes for perchlorate: comparison of analytical techniques.

    PubMed

    Collette, Timothy W; Williams, Ted L; Urbansky, Edward T; Magnuson, Matthew L; Hebert, Gretchen N; Strauss, Steven H

    2003-01-01

    Seven retail hydroponic nitrate fertilizer products, two liquid and five solid, were comparatively analyzed for the perchlorate anion (ClO4-) by ion chromatography (IC) with suppressed conductivity detection, complexation electrospray ionization mass spectrometry (cESI-MS), normal Raman spectroscopy, and infrared spectroscopy using an attenuated total reflectance crystal (ATR-FTIR) coated with a thin film of an organometallic ion-exchange compound. Three of the five solid products were found by all techniques to contain perchlorate at the level of approximately 100-350 mg kg(-1). The remaining products did not contain perchlorate above the detection level of any of the techniques. Comparative analysis using several analytical techniques that depend on different properties of perchlorate allow for a high degree of certainty in both the qualitative and quantitative determinations. This proved particularly useful for these samples, due to the complexity of the matrix. Analyses of this type, including multiple spectroscopic confirmations, may also be useful for other complicated matrixes (e.g., biological samples) or in forensic/regulatory frameworks where data are likely to be challenged. While the source of perchlorate in these hydroponic products is not known, the perchlorate-to-nitrate concentration ratio (w/w) in the aqueous extracts is generally consistent with the historical weight percent of water soluble components in caliche, a nitrate-bearing ore found predominantly in Chile. This ore, which is the only well-established natural source of perchlorate, is mined and used, albeit minimally, as a nitrogen source in some fertilizer products.

  12. A multilaboratory comparison of calibration accuracy and the performance of external references in analytical ultracentrifugation.

    PubMed

    Zhao, Huaying; Ghirlando, Rodolfo; Alfonso, Carlos; Arisaka, Fumio; Attali, Ilan; Bain, David L; Bakhtina, Marina M; Becker, Donald F; Bedwell, Gregory J; Bekdemir, Ahmet; Besong, Tabot M D; Birck, Catherine; Brautigam, Chad A; Brennerman, William; Byron, Olwyn; Bzowska, Agnieszka; Chaires, Jonathan B; Chaton, Catherine T; Cölfen, Helmut; Connaghan, Keith D; Crowley, Kimberly A; Curth, Ute; Daviter, Tina; Dean, William L; Díez, Ana I; Ebel, Christine; Eckert, Debra M; Eisele, Leslie E; Eisenstein, Edward; England, Patrick; Escalante, Carlos; Fagan, Jeffrey A; Fairman, Robert; Finn, Ron M; Fischle, Wolfgang; de la Torre, José García; Gor, Jayesh; Gustafsson, Henning; Hall, Damien; Harding, Stephen E; Cifre, José G Hernández; Herr, Andrew B; Howell, Elizabeth E; Isaac, Richard S; Jao, Shu-Chuan; Jose, Davis; Kim, Soon-Jong; Kokona, Bashkim; Kornblatt, Jack A; Kosek, Dalibor; Krayukhina, Elena; Krzizike, Daniel; Kusznir, Eric A; Kwon, Hyewon; Larson, Adam; Laue, Thomas M; Le Roy, Aline; Leech, Andrew P; Lilie, Hauke; Luger, Karolin; Luque-Ortega, Juan R; Ma, Jia; May, Carrie A; Maynard, Ernest L; Modrak-Wojcik, Anna; Mok, Yee-Foong; Mücke, Norbert; Nagel-Steger, Luitgard; Narlikar, Geeta J; Noda, Masanori; Nourse, Amanda; Obsil, Tomas; Park, Chad K; Park, Jin-Ku; Pawelek, Peter D; Perdue, Erby E; Perkins, Stephen J; Perugini, Matthew A; Peterson, Craig L; Peverelli, Martin G; Piszczek, Grzegorz; Prag, Gali; Prevelige, Peter E; Raynal, Bertrand D E; Rezabkova, Lenka; Richter, Klaus; Ringel, Alison E; Rosenberg, Rose; Rowe, Arthur J; Rufer, Arne C; Scott, David J; Seravalli, Javier G; Solovyova, Alexandra S; Song, Renjie; Staunton, David; Stoddard, Caitlin; Stott, Katherine; Strauss, Holger M; Streicher, Werner W; Sumida, John P; Swygert, Sarah G; Szczepanowski, Roman H; Tessmer, Ingrid; Toth, Ronald T; Tripathy, Ashutosh; Uchiyama, Susumu; Uebel, Stephan F W; Unzai, Satoru; Gruber, Anna Vitlin; von Hippel, Peter H; Wandrey, Christine; Wang, Szu-Huan; Weitzel, Steven E; Wielgus-Kutrowska, Beata; Wolberger, Cynthia; Wolff, Martin; Wright, Edward; Wu, Yu-Sung; Wubben, Jacinta M; Schuck, Peter

    2015-01-01

    Analytical ultracentrifugation (AUC) is a first principles based method to determine absolute sedimentation coefficients and buoyant molar masses of macromolecules and their complexes, reporting on their size and shape in free solution. The purpose of this multi-laboratory study was to establish the precision and accuracy of basic data dimensions in AUC and validate previously proposed calibration techniques. Three kits of AUC cell assemblies containing radial and temperature calibration tools and a bovine serum albumin (BSA) reference sample were shared among 67 laboratories, generating 129 comprehensive data sets. These allowed for an assessment of many parameters of instrument performance, including accuracy of the reported scan time after the start of centrifugation, the accuracy of the temperature calibration, and the accuracy of the radial magnification. The range of sedimentation coefficients obtained for BSA monomer in different instruments and using different optical systems was from 3.655 S to 4.949 S, with a mean and standard deviation of (4.304 ± 0.188) S (4.4%). After the combined application of correction factors derived from the external calibration references for elapsed time, scan velocity, temperature, and radial magnification, the range of s-values was reduced 7-fold with a mean of 4.325 S and a 6-fold reduced standard deviation of ± 0.030 S (0.7%). In addition, the large data set provided an opportunity to determine the instrument-to-instrument variation of the absolute radial positions reported in the scan files, the precision of photometric or refractometric signal magnitudes, and the precision of the calculated apparent molar mass of BSA monomer and the fraction of BSA dimers. These results highlight the necessity and effectiveness of independent calibration of basic AUC data dimensions for reliable quantitative studies.

  13. Comparison and validation of two analytical methods for measurement of urinary sucrose and fructose excretion

    PubMed Central

    Song, Xiaoling; Navarro, Sandi L.; Diep, Pho; Thomas, Wendy K.; Razmpoosh, Elena C.; Schwarz, Yvonne; Wang, Ching-Yun; Kratz, Mario; Neuhouser, Marian L.; Lampe, Johanna W.

    2013-01-01

    Urinary sugars excretion has been proposed as a potential biomarker for intake of sugars. In this study we compared two analytical methods [gas chromatography (GC) and enzymatic reactions – UV absorption] for quantifying urinary fructose and sucrose using 24-hour urine samples from a randomized cross-over controlled feeding study. All samples were successfully quantified by the GC method; however 21% and 1.9% of samples were below the detection limit of the enzymatic method for sucrose and fructose, respectively. While the correlation between the two methods was good for fructose (Pearson correlation 0.71), the correlation was weak for sucrose (Pearson correlation 0.27). We favor the GC method due to its better sensitivity, simplicity, and the ability to quantify fructose and sucrose directly in the same run. Of the 106 samples from 53 participants with complete urine collection after two study diets, 24-hour urinary fructose excretion was significantly associated with fructose intake. The sum of 24-hour urinary fructose and sucrose was significantly associated with total sugars consumption. However, variation in intakes of sugars explained only a modest amount of variation in urinary sugars excretion. In the unadjusted models, fructose intake explained 24.3% of urinary fructose excretion; and intake of total sugars 16.3% of the sum of urinary fructose and sucrose. The adjusted models explained 44.3% of urinary fructose excretion and 41.7% of the sum of urinary fructose and sucrose. Therefore, we caution using these biomarkers to predict sugars consumption before other factors that determine urinary sugars excretion are understood. PMID:24034568

  14. Comparison of two analyzers to determine selected venous blood analytes of Quaker parrots (Myiopsitta monachus).

    PubMed

    Rettenmund, Christy L; Heatley, J Jill; Russell, Karen E

    2014-06-01

    Point of care devices can assess electrolyte, blood gas, biochemical, and hematologic values in a critical care setting. Although these devices are commonly used in humans and companion mammals, few studies have assessed their use in avian species. This study compares electrolyte, hemoglobin (Hgb), hematocrit (Hct), acid-base, and venous blood gas parameters between the i-STAT and IRMA TruPoint blood gas analysis systems for 35 Quaker parrots. Agreement between the two analyzers and the effect of gender, time lag between sample analysis, and cartridge expiration were evaluated. Male birds had increased Hgb and Hct compared with females, independent of analyzer method. In expired i-STAT cartridges, only glucose significantly increased. Packed cell volume determined by centrifugation was higher than Hct, as calculated by either analyzer. The analyzers had good agreement for total carbon dioxide, bicarbonate, pH, and Hgb, fair agreement for potassium (K), ionized calcium (iCa), venous partial pressure of carbon dioxide, and base excess, and poor agreement for sodium (Na), venous partial pressure of oxygen (PO2), and oxygen saturation (SO2). Values for Na, iCa, PO2, and SO2 were significantly higher on the IRMA than the i-STAT, while K was significantly lower on the IRMA when compared with the i-STAT. The time lag between sample analyses on the i-STAT and IRMA did not be correlate to any analyte changes. Despite these differences, both the i-STAT and the IRMA appear to be acceptable clinical tools in avian critical care, although reference ranges for each analyzer should be created.

  15. Comparison of cultural and analytical methods for determination of aflatoxin production by Mississippi Delta Aspergillus isolates.

    PubMed

    Abbas, Hamed K; Zablotowicz, R M; Weaver, M A; Horn, B W; Xie, W; Shier, W T

    2004-03-01

    This study compared cultural and analytical methods for detecting aflatoxin production by Aspergillus species. Aspergillus isolates were obtained from various Mississippi Delta crops (corn, peanut, rice, cotton) and soils. Most of the isolates (99%) were A. flavus and the remainder comprised A. parasiticus and A. nomius. The following three cultural methods were evaluated on potato dextrose agar: fluorescence (FL) on beta-cyclodextrin-containing media (CD), yellow pigment (YP) formation in mycelium and medium, and color change after ammonium hydroxide vapor exposure (AV). Aflatoxins in culture extracts were confirmed by thin-layer chromatography (TLC) and quantified by enzyme-linked immunosorbent assay (ELISA). Of the 517 isolates, 314 produced greater than 20 ng/g of total aflatoxin based on ELISA, and 180 produced greater than 10 000 ng/g of aflatoxin in the medium. Almost all the toxigenic isolates (97%) were confirmed by TLC as producers. Of the toxigenic isolates, as determined by ELISA, 93%, 73%, and 70% gave positive FL, YP, and AV responses, respectively. Of the 203 isolates producing less than 20 ng/g of aflatoxin, 20%, 6%, and 0% of respective FL, YP, and AV methods gave false-positive responses. The 9% false-positive results from TLC fall within this range. This study showed good agreement among all tested cultural methods. However, these cultural techniques did not detect aflatoxin in all cultures that were found to produce aflatoxins by ELISA, LC/MS, and TLC. The best results were obtained when the AV color change and CD fluorescence methods were used together, yielding an overall success rate comparable to TLC but without the need for chemical extraction and the time and expense of TLC.

  16. Quantitative Proteomic Analysis of Serum Proteins from Oral Cancer Patients: Comparison of Two Analytical Methods

    PubMed Central

    Yang, Yan; Huang, Junwei; Rabii, Bahareh; Rabii, Ramin; Hu, Shen

    2014-01-01

    Serum proteomic analysis can be a valuable approach for the discovery of protein biomarkers for early detection or monitoring of a disease. In this study, two analytical methods were compared for quantification of serum proteins in patients with oral cancer. In the first approach, we quantified serum proteins between oral squamous cell carcinoma (OSCC) and healthy control subjects by performing in-solution digestion of serum proteins, isobaric tags for relative and absolute quantification (iTRAQ) labeling of the resulting peptides, strong cation exchange (SCX) fractionation of labeled peptides and finally capillary liquid chromatography with tandem mass spectrometry (LC-MS/MS) analysis of the peptides. In the second approach, we first separated serum proteins with SDS-PAGE. The gel-separated proteins were then digested with trypsin and the resulting peptides were labeled with iTRAQ and analyzed with LC-MS/MS for protein quantification. A total of 319 serum proteins were quantified with the first proteomic approach whereas a total of 281 proteins were quantified by the second proteomic approach. Most of the proteins were identified and quantified by both approaches, suggesting that these methods are similarly effective for serum proteome analysis. This study provides compelling evidence that quantitative serum proteomic analysis of OSCC is a valuable approach for identifying differentially expressed proteins in cancer patients’ circulation systems that may be used as potential biomarkers for disease detection. Further validation in large oral cancer patient populations may lead to a simple and low invasive clinical tool for OSCC diagnosis or monitoring. PMID:25196439

  17. Technical Evaluation Motor No. 10 (TEM-10)

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Technical Evaluation Motor No. 10 (TEM-10) was static fired on 27 Apr. 1993 at the Thiokol Corporation full-scale motor static test bay, T-24. This final test report documents the procedures, performance, and results of the static test firing of TEM-10. All observations, discussions, conclusions, and recommendations contained are final. Included is a presentation and discussion of TEM-10 performance, anomalies, and test results in concurrence with the objectives outlined in CTP-0110, Revision D, Space Shuttle Technical Evaluation Motor No. 10 (TEM-10) Static Fire Test Plan.

  18. Evaluation of antibacterial properties of novel phthalocyanines against Escherichia coli--comparison of analytical methods.

    PubMed

    Mikula, Premysl; Kalhotka, Libor; Jancula, Daniel; Zezulka, Stepan; Korinkova, Radka; Cerny, Jiri; Marsalek, Blahoslav; Toman, Petr

    2014-09-05

    We analyzed antibacterial effects of several novel phthalocyanines against Escherichia coli and evaluated the suitability of flow cytometry for the detection of antibacterial effects of phthalocyanines in comparison with routinely used cultivation. After 3h of exposure under cool white light eight cationic phthalocyanines showed very high antibacterial activity in the concentration of 2.00 mg L(-1) and four of them were even efficient in the concentration of 0.20 mg L(-1). Antibacterial activity of neutral and anionic compounds was considerably lower or even negligible. No antibacterial effect was detected when bacteria were exposed without illumination. Binding affinity to bacterial cells was found to represent an important parameter influencing phthalocyanine antibacterial activity that can be modified by total charge of peripheral substituents and by the presence of suitable functional groups inside them. Agglomeration of cells observed in suspensions treated with a higher concentration of certain cationic phthalocyanines (the strongest binders to bacterial membrane) affected cytometric measurements of total cell counts, thus without appropriate pretreatment of the sample before analysis this parameter seems not to be fully valid in the evaluation of phthalocyanine antibacterial activity. Cytometric measurement of cell membrane integrity appears to be a suitable and even more sensitive parameter than cultivation.

  19. New analytical method for solving Burgers' and nonlinear heat transfer equations and comparison with HAM

    NASA Astrophysics Data System (ADS)

    Rashidi, M. M.; Erfani, E.

    2009-09-01

    In this study, we present a numerical comparison between the differential transform method (DTM) and the homotopy analysis method (HAM) for solving Burgers' and nonlinear heat transfer problems. The first differential equation is the Burgers' equation serves as a useful model for many interesting problems in applied mathematics. The second one is the modeling equation of a straight fin with a temperature dependent thermal conductivity. In order to show the effectiveness of the DTM, the results obtained from the DTM is compared with available solutions obtained using the HAM [M.M. Rashidi, G. Domairry, S. Dinarvand, Commun. Nonlinear Sci. Numer. Simul. 14 (2009) 708-717; G. Domairry, M. Fazeli, Commun. Nonlinear Sci. Numer. Simul. 14 (2009) 489-499] and whit exact solutions. The method can easily be applied to many linear and nonlinear problems. It illustrates the validity and the great potential of the differential transform method in solving nonlinear partial differential equations. The obtained results reveal that the technique introduced here is very effective and convenient for solving nonlinear partial differential equations and nonlinear ordinary differential equations that we are found to be in good agreement with the exact solutions.

  20. Factor Analytic Replication and Model Comparison of the BASC-2 Behavioral and Emotional Screening System.

    PubMed

    Splett, Joni Williams; Raborn, Anthony; Lane, Kathleen Lynne; Binney, Alexandra J; Chafouleas, Sandra M

    2017-03-06

    We conducted this study to add to literature of previous conflicting factorial examinations of the BASC-2 Behavioral and Emotional Screening System (BESS), Teacher Form-Child/Adolescent. Data were collected by an urban school district in the southeastern United States including 2,228 students rated by 120 teachers in Fall 2014 and 1,955 students rated by 104 teachers in Spring 2015. In both samples, we replicated and then conceptually and statistically compared factor models to examine the (a) 4-factor structure from which the BESS Teacher Form was developed, and (b) existence of a general factor currently being used. Previous studies examined the 4-factor and bifactor structure of the BESS Teacher Form on separate samples. Our model comparison results support a multidimensional interpretation. We recovered similar fit statistics and standardized factor loadings as previous factor analyses. However, measures of variance accounted for by the general factor were below recommended thresholds of a unidimensional construct. We recommend advancing a factorial model that represents a weighted combination of general and specific factors, but do not support continued use of a unidimensional total T score. Limitations and implications of the study are discussed. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  1. Prediction of glomerular filtration rate from serum concentration of cystatin C: comparison of two analytical methods.

    PubMed

    Donadio, Carlo; Kanaki, Angeliki; Caprio, Francesca; Donadio, Elena; Tognotti, Danika; Olivieri, Luigi

    2012-07-01

    The aim of this study was to compare two methods used to measure serum cystatin C (Cys) and their accuracy to predict glomerular filtration rate (GFR). Three hundred and sixty-seven adult chronic kidney disease (CKD) patients with different functional impairments participated in this study. GFR was determined as the renal clearance of 99mTc-DTPA. Serum concentrations of cystatin C (SCys) were determined with an immunonephelometric method and with an immunoturbidimetric method. A very high linear correlation was found between the two measurements of SCys (r=0.929). The mean difference of SCysTurb-SCysNeph was 0.02±0.43 mg/L (not significant). A high logarithmic correlation was also found between SCys and GFR (r was 0.919 for SCysNeph and 0.937 for SCysTurb). By means of multiple regression analysis, we developed formulae to predict GFR from SCysNeph, SCysTurb and SCr. For comparison, GFR was predicted using published formulae. A good agreement was found between predicted GFR and measured GFR. The results showed that the accuracy of SCysNeph, SCysTurb and SCr and of the different prediction formulae were quite similar. The immunoturbidimetric method seems adequate to measure SCys and to predict GFR and its impairment in CKD, at least similar to the immunonephelometric method. The accuracy of SCys and of derived formulae was not higher than that of SCr and SCr-based formulae.

  2. A comparison between anisotropic analytical and multigrid superposition dose calculation algorithms in radiotherapy treatment planning

    SciTech Connect

    Wu, Vincent W.C.; Tse, Teddy K.H.; Ho, Cola L.M.; Yeung, Eric C.Y.

    2013-07-01

    Monte Carlo (MC) simulation is currently the most accurate dose calculation algorithm in radiotherapy planning but requires relatively long processing time. Faster model-based algorithms such as the anisotropic analytical algorithm (AAA) by the Eclipse treatment planning system and multigrid superposition (MGS) by the XiO treatment planning system are 2 commonly used algorithms. This study compared AAA and MGS against MC, as the gold standard, on brain, nasopharynx, lung, and prostate cancer patients. Computed tomography of 6 patients of each cancer type was used. The same hypothetical treatment plan using the same machine and treatment prescription was computed for each case by each planning system using their respective dose calculation algorithm. The doses at reference points including (1) soft tissues only, (2) bones only, (3) air cavities only, (4) soft tissue-bone boundary (Soft/Bone), (5) soft tissue-air boundary (Soft/Air), and (6) bone-air boundary (Bone/Air), were measured and compared using the mean absolute percentage error (MAPE), which was a function of the percentage dose deviations from MC. Besides, the computation time of each treatment plan was recorded and compared. The MAPEs of MGS were significantly lower than AAA in all types of cancers (p<0.001). With regards to body density combinations, the MAPE of AAA ranged from 1.8% (soft tissue) to 4.9% (Bone/Air), whereas that of MGS from 1.6% (air cavities) to 2.9% (Soft/Bone). The MAPEs of MGS (2.6%±2.1) were significantly lower than that of AAA (3.7%±2.5) in all tissue density combinations (p<0.001). The mean computation time of AAA for all treatment plans was significantly lower than that of the MGS (p<0.001). Both AAA and MGS algorithms demonstrated dose deviations of less than 4.0% in most clinical cases and their performance was better in homogeneous tissues than at tissue boundaries. In general, MGS demonstrated relatively smaller dose deviations than AAA but required longer computation time.

  3. Comparison of analytical and numerical analysis of the reference region model for DCE-MRI.

    PubMed

    Lee, Joonsang; Cárdenas-Rodríguez, Julio; Pagel, Mark D; Platt, Simon; Kent, Marc; Zhao, Qun

    2014-09-01

    This study compared three methods for analyzing DCE-MRI data with a reference region (RR) model: a linear least-square fitting with numerical analysis (LLSQ-N), a nonlinear least-square fitting with numerical analysis (NLSQ-N), and an analytical analysis (NLSQ-A). The accuracy and precision of estimating the pharmacokinetic parameter ratios KR and VR, where KR is defined as a ratio between the two volume transfer constants, K(trans,TOI) and K(trans,RR), and VR is the ratio between the two extracellular extravascular volumes, ve,TOI and ve,RR, were assessed using simulations under various signal-to-noise ratios (SNRs) and temporal resolutions (4, 6, 30, and 60s). When no noise was added, the simulations showed that the mean percent error (MPE) for the estimated KR and VR using the LLSQ-N and NLSQ-N methods ranged from 1.2% to 31.6% with various temporal resolutions while the NLSQ-A method maintained a very high accuracy (<1.0×10(-4) %) regardless of the temporal resolution. The simulation also indicated that the LLSQ-N and NLSQ-N methods appear to underestimate the parameter ratios more than the NLSQ-A method. In addition, seven in vivo DCE-MRI datasets from spontaneously occurring canine brain tumors were analyzed with each method. Results for the in vivo study showed that KR (ranging from 0.63 to 3.11) and VR (ranging from 2.82 to 19.16) for the NLSQ-A method were both higher than results for the other two methods (KR ranging from 0.01 to 1.29 and VR ranging from 1.48 to 19.59). A temporal downsampling experiment showed that the averaged percent error for the NLSQ-A method (8.45%) was lower than the other two methods (22.97% for LLSQ-N and 65.02% for NLSQ-N) for KR, and the averaged percent error for the NLSQ-A method (6.33%) was lower than the other two methods (6.57% for LLSQ-N and 13.66% for NLSQ-N) for VR. Using simulations, we showed that the NLSQ-A method can estimate the ratios of pharmacokinetic parameters more accurately and precisely than the NLSQ-N and

  4. Genome Wide Association for Addiction: Replicated Results and Comparisons of Two Analytic Approaches

    PubMed Central

    Drgon, Tomas; Zhang, Ping-Wu; Johnson, Catherine; Walther, Donna; Hess, Judith; Nino, Michelle; Uhl, George R.

    2010-01-01

    likely to complement classical, “template” GWA approaches in which “genome wide” levels of significance are sought for SNP data from single case vs control comparisons. PMID:20098672

  5. Adhesive contact of rough surfaces: comparison between numerical calculations and analytical theories.

    PubMed

    Carbone, G; Scaraggi, M; Tartaglino, U

    2009-09-01

    The authors have employed a numerical procedure to analyse the adhesive contact between a soft elastic layer and a rough rigid substrate. The solution to the problem, which belongs to the class of the free boundary problems, is obtained by calculating Green's function which links the pressure distribution to the normal displacements at the interface. The problem is then formulated in the form of a Fredholm integral equation of the first kind with a logarithmic kernel. The boundaries of the contact area are calculated by requiring the energy of the system to be stationary. This methodology has been employed to study the adhesive contact between an elastic semi-infinite solid and a randomly rough rigid profile with a self-affine fractal geometry. We show that, even in the presence of adhesion, the true contact area still linearly depends on the applied load. The numerical results are then critically compared with the predictions of an extended version of Persson's contact mechanics theory, which is able to handle anisotropic surfaces, as 1D interfaces. It is shown that, for any given load, Persson's theory underestimates the contact area by about 50% in comparison with our numerical calculations. We find that this discrepancy is larger than for 2D rough surfaces in the case of adhesionless contact. We argue that this increased difference might be explained, at least partially, by considering that Persson's theory is a mean-field theory in spirit, so it should work better for 2D rough surfaces rather than for 1D rough surfaces. We also observe that the predicted value of separation is in agreement with our numerical results as well as the exponents of the power spectral density of the contact pressure distribution and of the elastic displacement of the solid. Therefore, we conclude that Persson's theory captures almost exactly the main qualitative behaviour of the rough contact phenomena.

  6. [Analytical method and comparison for static and dynamic headspace gas chromatography of anisole in water].

    PubMed

    Zhang, Yan; Qian, Jie-feng; Liu, Lan-xia; Zhao, Hui-qin

    2013-01-01

    To establish and compare the method of static headspace gas chromatography hydrogen flame detector (static headspace method) and purge and trap gas chromatography-mass spectrometry (dynamic headspace method) of anisole in water. Nitrogen gas was used as carrier gas in the static headspace method, 5 g NaCl as matrix modifier was added into 10 ml water. The sample was balanced with high speed vibration at 75°C for 30 min, and anisole was detected by gas chromatography and quantified with external standard. Helium was used as carrier gas in dynamic headspace method, 5.0 ml water and 0.004 mg/L internal standard fluorobenzene was purged into the purge and trap apparatus. After purging, trapping and desorption, anisole was detected by the gas chromatography-mass spectrograph, confirmed by the retention time and comparison of mass-spectrogram in spectrum library and quantified with internal standard. The repeatability and sensitivity of assay were evaluated. A good linear range for anisole was observed in static headspace gas chromatography and dynamic headspace gas chromatography-mass spectrometry, within the range of 10 - 500 µg/L and 0.5 - 60.0 µg/L respectively. The linear regression equation was Y = 782.150X + 1.3446 and Y = 0.0358X - 0.0209 respectively, both the correlation coefficient ≥ 0.999. The detection limit (LOD) were 0.002 µg/L and 0.110 µg/L, the lower limit of quantitation (LOQ) were 0.006 µg/L and 0.350 µg/L, the relative standard deviation (RSD) were 1.8% - 2.3% and 2.0% - 3.4%, and the spiking recovery were 93% - 101% and 96% - 101% respectively. The methods of static headspace gas chromatography and dynamic headspace gas chromatography-mass spectrometry are simple and can measure anisole in water quickly, sensitively and accurately.

  7. Multicenter Comparison of Three Different Analytical Systems for Evaluation of DNA Banding Patterns from Cryptococcus neoformans

    PubMed Central

    Cardinali, Gianluigi; Martini, Alessandro; Preziosi, Roberta; Bistoni, Francesco; Baldelli, Franco

    2002-01-01

    The enormous improvement of molecular typing techniques for epidemiological and clinical studies has not always been matched by an equivalent effort in applying optimal criteria for the analysis of both phenotypic and molecular data. In spite of the availability of a large collection of statistical and phylogenetic methods, the vast majority of commercial packages are limited by using only the unweighted pair group method with arithmetic mean algorithm to construct trees and by considering electrophoretic pattern only as migration distances. The latter method has serious drawbacks when different runs (separate gels) of the same molecular analysis are to be compared. This work presents a multicenter comparison of three different systems of banding pattern analysis on random amplified polymorphic DNA, (GACA)4, and contour-clamped homogeneous electric field patterns from strains of Cryptococcus neoformans var. neoformans isolated in different clinical and geographical situations and a standard Saccharomyces cerevisiae strain employed as an outgroup. The systems considered were evaluated for their actual ability to(i) recognize identities, (ii) define complete differences (i.e., the ability to place S. cerevisiae out of the C. neoformans cluster), and (iii) estimate the extent of similarity among different strains. The ability to cluster strains according to the patient from which they were isolated was also evaluated. The results indicate that different algorithms do indeed produce divergent trees, both in overall topology and in clustering of individual strains, thus suggesting that care must be taken by individual investigators to use the most appropriate procedure and by the scientific community in defining a consensus system. PMID:12037071

  8. Adhesive contact of rough surfaces: Comparison between numerical calculations and analytical theories

    NASA Astrophysics Data System (ADS)

    Carbone, G.; Scaraggi, M.; Tartaglino, U.

    2009-09-01

    The authors have employed a numerical procedure to analyse the adhesive contact between a soft elastic layer and a rough rigid substrate. The solution to the problem, which belongs to the class of the free boundary problems, is obtained by calculating Green’s function which links the pressure distribution to the normal displacements at the interface. The problem is then formulated in the form of a Fredholm integral equation of the first kind with a logarithmic kernel. The boundaries of the contact area are calculated by requiring the energy of the system to be stationary. This methodology has been employed to study the adhesive contact between an elastic semi-infinite solid and a randomly rough rigid profile with a self-affine fractal geometry. We show that, even in the presence of adhesion, the true contact area still linearly depends on the applied load. The numerical results are then critically compared with the predictions of an extended version of Persson’s contact mechanics theory, which is able to handle anisotropic surfaces, as 1D interfaces. It is shown that, for any given load, Persson’s theory underestimates the contact area by about 50% in comparison with our numerical calculations. We find that this discrepancy is larger than for 2D rough surfaces in the case of adhesionless contact. We argue that this increased difference might be explained, at least partially, by considering that Persson’s theory is a mean-field theory in spirit, so it should work better for 2D rough surfaces rather than for 1D rough surfaces. We also observe that the predicted value of separation is in agreement with our numerical results as well as the exponents of the power spectral density of the contact pressure distribution and of the elastic displacement of the solid. Therefore, we conclude that Persson’s theory captures almost exactly the main qualitative behaviour of the rough contact phenomena. in here

  9. In situ TEM electromechanical testing of nanowires and nanotubes.

    PubMed

    Espinosa, Horacio D; Bernal, Rodrigo A; Filleter, Tobin

    2012-11-05

    The emergence of one-dimensional nanostructures as fundamental constituents of advanced materials and next-generation electronic and electromechanical devices has increased the need for their atomic-scale characterization. Given its spatial and temporal resolution, coupled with analytical capabilities, transmission electron microscopy (TEM) has been the technique of choice in performing atomic structure and defect characterization. A number of approaches have been recently developed to combine these capabilities with in-situ mechanical deformation and electrical characterization in the emerging field of in-situ TEM electromechanical testing. This has enabled researchers to establish unambiguous synthesis-structure-property relations for one-dimensional nanostructures. In this article, the development and latest advances of several in-situ TEM techniques to carry out mechanical and electromechanical testing of nanowires and nanotubes are reviewed. Through discussion of specific examples, it is shown how the merging of several microsystems and TEM has led to significant insights into the behavior of nanowires and nanotubes, underscoring the significant role in-situ techniques play in the development of novel nanoscale systems and materials.

  10. New TEM variant (TEM-92) produced by Proteus mirabilis and Providencia stuartii isolates.

    PubMed

    de Champs, C; Monne, C; Bonnet, R; Sougakoff, W; Sirot, D; Chanal, C; Sirot, J

    2001-04-01

    The sequences of the bla(TEM) genes encoding TEM-92 in Proteus mirabilis and Providencia stuartii isolates were determined and were found to be identical. Except for positions 218 (Lys-6) and 512 (Lys-104), the nucleotide sequence of bla(TEM-92) was identical to that of bla(TEM-20), including the sequence of the promoter region harboring a 135-bp deletion combined with a G-162-->T substitution. The deduced amino acid sequence of TEM-92 differed from that of TEM-52 by the presence of a substitution (Gln-6-->Lys) in the peptide signal.

  11. Assessment of TEM Cells for Whole Aircraft EMV Testing

    DTIC Science & Technology

    2007-05-01

    known to be due to cavity resonances within the cell. A novel method of active mode cancellation has been developed through CEM modelling together with...TEM Cell, OATS and Free Space Comparison . . . . . . . . . . . . . . . . . . 19 2.3.1 FEKO Models...accredited EMC test houses. The EMC/EMI characteristics of a box forms the basis of analysis at the system level once installed in the aircraft. The intra

  12. Overlooking the obvious: a meta-analytic comparison of digit symbol coding tasks and other cognitive measures in schizophrenia.

    PubMed

    Dickinson, Dwight; Ramsey, Mary E; Gold, James M

    2007-05-01

    In focusing on potentially localizable cognitive impairments, the schizophrenia meta-analytic literature has overlooked the largest single impairment: on digit symbol coding tasks. To compare the magnitude of the schizophrenia impairment on coding tasks with impairments on other traditional neuropsychological instruments. MEDLINE and PsycINFO electronic databases and reference lists from identified articles. English-language studies from 1990 to present, comparing performance of patients with schizophrenia and healthy controls on coding tasks and cognitive measures representing at least 2 other cognitive domains. Of 182 studies identified, 40 met all criteria for inclusion in the meta-analysis. Means, standard deviations, and sample sizes were extracted for digit symbol coding and 36 other cognitive variables. In addition, we recorded potential clinical moderator variables, including chronicity/severity, medication status, age, and education, and potential study design moderators, including coding task variant, matching, and study publication date. Main analyses synthesized data from 37 studies comprising 1961 patients with schizophrenia and 1444 comparison subjects. Combination of mean effect sizes across studies by means of a random effects model yielded a weighted mean effect for digit symbol coding of g = -1.57 (95% confidence interval, -1.66 to -1.48). This effect compared with a grand mean effect of g = -0.98 and was significantly larger than effects for widely used measures of episodic memory, executive functioning, and working memory. Moderator variable analyses indicated that clinical and study design differences between studies had little effect on the coding task effect. Comparison with previous meta-analyses suggested that current results were representative of the broader literature. Subsidiary analysis of data from relatives of patients with schizophrenia also suggested prominent coding task impairments in this group. The 5-minute digit symbol coding

  13. Comparison of Pre-Analytical FFPE Sample Preparation Methods and Their Impact on Massively Parallel Sequencing in Routine Diagnostics

    PubMed Central

    Heydt, Carina; Fassunke, Jana; Künstlinger, Helen; Ihle, Michaela Angelika; König, Katharina; Heukamp, Lukas Carl; Schildhaus, Hans-Ulrich; Odenthal, Margarete; Büttner, Reinhard; Merkelbach-Bruse, Sabine

    2014-01-01

    Over the last years, massively parallel sequencing has rapidly evolved and has now transitioned into molecular pathology routine laboratories. It is an attractive platform for analysing multiple genes at the same time with very little input material. Therefore, the need for high quality DNA obtained from automated DNA extraction systems has increased, especially to those laboratories which are dealing with formalin-fixed paraffin-embedded (FFPE) material and high sample throughput. This study evaluated five automated FFPE DNA extraction systems as well as five DNA quantification systems using the three most common techniques, UV spectrophotometry, fluorescent dye-based quantification and quantitative PCR, on 26 FFPE tissue samples. Additionally, the effects on downstream applications were analysed to find the most suitable pre-analytical methods for massively parallel sequencing in routine diagnostics. The results revealed that the Maxwell 16 from Promega (Mannheim, Germany) seems to be the superior system for DNA extraction from FFPE material. The extracts had a 1.3–24.6-fold higher DNA concentration in comparison to the other extraction systems, a higher quality and were most suitable for downstream applications. The comparison of the five quantification methods showed intermethod variations but all methods could be used to estimate the right amount for PCR amplification and for massively parallel sequencing. Interestingly, the best results in massively parallel sequencing were obtained with a DNA input of 15 ng determined by the NanoDrop 2000c spectrophotometer (Thermo Fisher Scientific, Waltham, MA, USA). No difference could be detected in mutation analysis based on the results of the quantification methods. These findings emphasise, that it is particularly important to choose the most reliable and constant DNA extraction system, especially when using small biopsies and low elution volumes, and that all common DNA quantification techniques can be used for

  14. OBSERVATION OF DIPOLAR FERROMAGNETISM BY TEM TECHNIQUES.

    SciTech Connect

    BELEGGIA, M.ZHU,Y.TANDON,S.ET AL.

    2004-08-01

    Magnetostatic interactions play a central role in determining the magnetic response of an array of patterned magnetic elements or magnetized nanoparticles of given shape. The Fourier space approach recently introduced for the analytical computation of the demagnetizing tensor, field and energy for particles of arbitrary shape [1], has been recently extended to cover interactions between elements [2]. The main achievement has been the definition of a generalized dipole-dipole interaction for cylindrical objects, which takes into account the influence of shape anisotropy without resorting to,any kind of approximations [3]. Once the interaction energy is available, it becomes possible to evaluate the minimum energy state of the system for a given set of external parameters (such as applied field, aspect ratio, distance between elements). It turns out that, below a critical combination of aspect ratios and distances, the system undergoes a phase transition, changing abruptly from a closure domain state, with zero net magnetization, to a dipolar ferromagnetic state with a net magnetization which depends on the interaction strength between the elements. In order to observe this phenomenon by TEM, it is necessary to estimate the feasibility of the experiment by a series of simulations. Figure 1 shows the electron optical phase shifts for the system of three weakly (a-c) and strongly (d) interacting disks. The elements have a radius of 50 nm, a thickness of 5 nm (aspect ratio 1/20), and are uniformly magnetized at 2 T. By comparing Fig.1 (c) and (d), it can be seen that the fingerprint of the transition is the presence of fringing fields around the elements, revealed by the cosine fringes which resemble a dipole-like field in (d). When the system is in the closure-domain state, as in (a-c), no fringing field can be observed on a large scale. Figure 2 shows a set of Fresnel images, calculated for the same configurations as in Fig.1. As the Fresnel technique is scarcely

  15. Technical Evaluation Motor no. 5 (TEM-5)

    NASA Technical Reports Server (NTRS)

    Cook, M.

    1990-01-01

    Technical Evaluation Motor No. 5 (TEM-5) was static test fired at the Thiokol Corporation Static Test Bay T-97. TEM-5 was a full scale, full duration static test fire of a high performance motor (HPM) configuration solid rocket motor (SRM). The primary purpose of TEM static tests is to recover SRM case and nozzle hardware for use in the redesigned solid rocket motor (RSRM) flight program. Inspection and instrumentation data indicate that the TEM-5 static test firing was successful. The ambient temperature during the test was 41 F and the propellant mean bulk temperature (PMBT) was 72 F. Ballistics performance values were within the specified requirements. The overall performance of the TEM-5 components and test equipment was nominal. Dissembly inspection revealed that joint putty was in contact with the inner groove of the inner primary seal of the ignitor adapter-to-forward dome (inner) joint gasket; this condition had not occurred on any previous static test motor or flight RSRM. While no qualification issues were addressed on TEM-5, two significant component changes were evaluated. Those changes were a new vented assembly process for the case-to-nozzle joint and the installation of two redesigned field joint protection systems. Performance of the vented case-to-nozzle joint assembly was successful, and the assembly/performance differences between the two field joint protection system (FJPS) configurations were compared.

  16. Automated measurement of 25-OH Vitamin D on the LUMIPULSE(®) G1200: analytical verification and method comparison.

    PubMed

    Parra, Marina; Foj, Laura; Filella, Xavier

    2016-07-01

    Because of its potential value in several pathologies, clinical interest in 25-hydroxy Vitamin D (25OH-D) is increasing. However, the standardisation of assays remains a significant problem. Our aim was to evaluate the performance of the novel Lumipulse G 25-OH Vitamin D assay (Fujirebio), comparing results with the Liaison (Diasorin) method. Analytical verification of the Lumipulse G 25-OH Vitamin D assay was performed. Both methods were compared using sera from 226 patients, including 111 patients with chronic renal failure (39 on haemodialysis) and 115 patients without renal failure. In addition, clinical concordance between assays was assessed. For Lumipulse G 25-OH Vitamin D assay, the limit of detection was 0.3 ng/mL, and the limit of quantification was 2.5 ng/mL with a 9.7% of coefficient of variation. Intra-and inter-assay coefficients of variation were <2.3 and <1.8% (25.4-50.0 ng/mL), respectively. Dilution linearity was in the range of 4.5-144.5 ng/mL. Method comparison resulted in a mean difference of -6.5% (95% CI from -8.8 to -4.1) for all samples between Liaison and Lumipulse G. Clinical concordance assessed by Kappa Index was 0.66. Lumipulse G 25-OH Vitamin D showed a good clinical concordance with the Liaison assay, although overall results measured in Lumipulse were higher by an average of 6.5%.

  17. Structure of penetrable-rod fluids: exact properties and comparison between Monte Carlo simulations and two analytic theories.

    PubMed

    Malijevský, Alexandr; Santos, Andrés

    2006-02-21

    Bounded potentials are good models to represent the effective two-body interaction in some colloidal systems, such as the dilute solutions of polymer chains in good solvents. The simplest bounded potential is that of penetrable spheres, which takes a positive finite value if the two spheres are overlapped, being 0 otherwise. Even in the one-dimensional case, the penetrable-rod model is far from trivial, since interactions are not restricted to nearest neighbors and so its exact solution is not known. In this paper the structural properties of one-dimensional penetrable rods are studied. We first derive the exact correlation functions of the penetrable-rod fluids to second order in density at any temperature, as well as in the high-temperature and zero-temperature limits at any density. It is seen that, in contrast to what is generally believed, the Percus-Yevick equation does not yield the exact cavity function in the hard-rod limit. Next, two simple analytic theories are constructed: a high-temperature approximation based on the exact asymptotic behavior in the limit T--> infinity and a low-temperature approximation inspired by the exact result in the opposite limit T--> 0. Finally, we perform Monte Carlo simulations for a wide range of temperatures and densities to assess the validity of both theories. It is found that they complement each other quite well, exhibiting a good agreement with the simulation data within their respective domains of applicability and becoming practically equivalent on the borderline of those domains. A comparison with numerical solutions of the Percus-Yevick and the hypernetted-chain approximations is also carried out. Finally, a perspective on the extension of our two heuristic theories to the more realistic three-dimensional case is provided.

  18. Visualizing DNA Nanoparticle Motion under Graphene Liquid Cell TEM

    NASA Astrophysics Data System (ADS)

    Chen, Qian; Smith, Jessica; Park, Jungwon; Lee, Somin; Zettl, Alex; Alivisatos, Paul

    2013-03-01

    We think of a simple colloidal nanocrystal as one type of artificial atoms. They mutually interact, cluster into artificial molecules, and further arrange into macroscopically functional artificial solids. The ``atomic'' resolution dynamics of this bottom-up strategy in materials design is studied here in a system of artificial molecules composed of DNA and nanoparticle. The observation of dynamics in their liquid environment is recently enabled by graphene liquid cell transmission electron microscopy (TEM). In comparison to conventional TEM, wherein the assembled 3D artificial structures are dried out during sample preparation and thus are collapsed, this graphene liquid cell introduces a special local liquid structure that retains the conformations as well as the dynamics of the assemblies. In situ imaging of correlated motions of DNA and nanoparticle provides insights into the design principles of artificial nanocrystal molecules and solids linked by DNA.

  19. [Transanal endoscopic microsurgery (TEM) our experience].

    PubMed

    Robek, O; Čan, V; Svoboda, T; Hemmelová, B; Kala, Z; Hrivnák, R

    2016-01-01

    The purpose of this paper is to present our experience with transanal endoscopic microsurgery (TEM) as an operative approach in a selected group of patients with rectal tumours. We present a retrospective study of 80 patients operated for rectal tumour using TEM. Specific preoperative and postoperative indicators were gathered and statistically evaluated. We assessed histological examination before the surgery and definitive histology of the resected tumour, resection depth and basic demographic data of our patients. Our experience suggests that there is no significant difference between the age of patients according to sex, even if malignant and benign tumours are assessed separately. The majority of our operated patients were male patients, mean age of 64 years who were primarily referred to our department because of bleeding low-grade adenomas of the rectum. In 17 patients a malignant tumour was diagnosed based on final histopathologic examination. None of them had signs of malignancy before the surgery. In the hands of an experienced surgeon, TEM is a feasible option of radical removal of rectal, locally not advanced malignancies if within reach of TEM rectoscope. TEM is a safe procedure that does not result in any alteration of rectal sphincter functions. Possible false negative preoperative benign diagnosis leads us to approach radical removal of the tumour with full wall thickness resection. Although the posterior aspect of the rectum is an optimal location for the rectoscope, anterior tumours were found in almost one half of our patients. Considering technical feasibility of the rectal wall suture, the base of the tumour should not extend beyond one half of the rectal circumference. Low non-stenotising noninvasive tumours of the rectum are suitable for TEM. Our good results are particularly due to strict patient selection criteria, mastering the operating technique and long-time experience. transanal endoscopic microsurgery (TEM) benign rectal tumours

  20. Electron trajectories in a helical wiggler with a uniform axial guide field: a comparison of numerical results with results obtained using an approximate but analytical method

    NASA Astrophysics Data System (ADS)

    Donohue, J. T.; Gouard, Ph.; Rullier, J. L.

    1995-04-01

    A comparison is made between two methods of calculating electron trajectories in a magnetic field consisting of a helical wiggler and a uniform axial guide field. The code SOLITUDE, developed by Gouard, was used to calculate with high precision the trajectories of electrons whose initial positions and velocities were chosen at random from a Gaussian distribution. After propagation through an adiabatic entry, the positions and velocities at the point where the wiggler field becomes steady were used as input to an analytical calculation developed by Donohue and Rullier. Although the calculation is analytic, the method involves truncating the true Hamiltonian, and is therefore not exact. Despite this, generally good agreement is found between the trajectories generated by the two methods, in both the normal and reversed-field configurations. The analytical approach provides physical insight into certain unusual aspects of some of the numerically generated trajectories. Several illustrative examples are compared in detail.

  1. Cold air study of the effect on turbine stator blade aerodynamic performance of coolant ejection from various trailing edge slot geometries. 2: Comparison of experimental and analytical results

    NASA Technical Reports Server (NTRS)

    Prust, H. W., Jr.

    1975-01-01

    Experimentally determined efficiencies of turbine stator blades having trailing-edge coolant ejection are compared with efficiencies predicted from two previously published approximate analytical methods. The experimental results were obtained from two-dimensional data with the temperature of the primary and coolant flows both being nearly ambient. Data from five stator blade configurations having different slotted trailing-edge geometries were included in the comparison. The two analytical methods gave results which agreed reasonably well with experimental results. An average of the absolute values of differences between experimental and predicted efficiencies for all five blade configurations showed that one method gave average efficiency differences which were about 1.3 percent different than experimental efficiencies, while the other method gave average efficiency differences that were about 0.7 percent different than experimental. However, in some instances, maximum differences of as much as 4 percent occurred. A comparison between experimental and analytical results indicated that the ratio of trailing-edge slot width to trailing-edge thickness influences the measured efficiencies to a greater extent than is accounted for by either analytical model.

  2. TEM-STM for Novel Nanotechnological Experimentation

    NASA Astrophysics Data System (ADS)

    Vaughn, Joel

    2005-03-01

    We present the design and construction of a miniature scanning tunneling microscope (STM) to be used inside a transmission electron microscope (TEM). In our system, the entire STM head is fitted inside the TEM sample holder, which allows for both TEM imaging/diffraction and STM-tip indentation experiments. The positioning of STM-tip over the desired sample locations can be guided through the real time TEM images. In addition to the nano indentation experiments, the STM program also allows the state-of-the-art control of atom/molecule manipulation procedures [1]. This hybrid TEM-STM system can be used for nanoscale manipulation, electrical characterization and mechanical strength examination of various nanomaterials including nanowires, nanotubes and quantum dots. [1]. S.-W. Hla, K.-F. Braun, V. Iancu, A. Deshpande, Nano Lett. 4 (2004) 1997-2001. This work is financially supported by the NSF-NIRT grant no. DMR- 0304314 and the US-DOE grant no. DE-FG02-02ER46012.

  3. Problems at the Leading Edge of Space Weathering as Revealed by TEM Combined with Surface Science Techniques

    NASA Astrophysics Data System (ADS)

    Christoffersen, R.; Dukes, C. A.; Keller, L. P.; Rahman, Z.; Baragiola, R. A.

    2015-11-01

    Analytical field-emission TEM techniques cross-correlated with surface analyses by X-ray photoelectron spectroscopy (XPS) provides a unique two-prong approach for characterizing how solar wind ion processing contributes to space weathering.

  4. TEM-nanoindentation studies of semiconducting structures.

    PubMed

    Le Bourhis, E; Patriarche, G

    2007-01-01

    This paper reviews the application of nanoindentation coupled with transmission electron microscopy (TEM) to investigations of the plastic behaviour of semiconducting structures and its implication for device design. Instrumented nanoindentation has been developed to extract the mechanical behaviour of small volumes scaled to those encountered in semiconductor heterostructures. We illustrate that TEM is a powerful complementary tool for the study of local plasticity induced by nanoindentation. TEM-nanoindentation allows for detailed understanding of the plastic deformation in semiconducting structures and opens practical routes for improvement of devices. Performances of heterostructures are deteriously affected by dislocations that relax the lattice mismatched layers. Different ways to obtain compliant substructures are being developed in order to concentrate the plastic relaxation underneath the heterostructure. Such approaches allow for mechanical design of micro- and opto-electronic devices to be considered throughout the fabrication process.

  5. Technical Evaluation Motor No. 7 (TEM-07)

    NASA Technical Reports Server (NTRS)

    Hugh, Phil

    1991-01-01

    Technical Evaluation Motor Number 7 (TEM-7) was a full scale, full-duration static test firing of a high performance motor (HPM) configuration solid rocket motor (SRM) with nozzle vectoring. The static test fire occurred on 11 December 1990 at the Thiokol Corporation Static Test Bay T-97. Documented here are the procedures, performance, and results available through 22 January 1991. Critical post test hardware activities and assessment of the test data are not complete. A completed test report will be submitted 60 days after the test date. Included here is a presentation and discussion of the TEM-7 performance, anomalies, and test result concurrence with the objectives outlined in CTP-0107 Revision A, Space Shuttle Technical Evaluation Motor number 7 (TEM-07) Static Fire Test Plan.

  6. Comparison Between a Rapid Biological Screening Method (EPA 4425) for TCDDs/TCDFs and Chemical Analytical Methods

    SciTech Connect

    Anderson, Jack W.; Jones, Jennifer M.; McCoy, Daniel L.; Fujita, Akira; Yamamoto, Taichi; Iijima, Satoshi

    2003-08-01

    Seven polychlorinated dibenzo-p-dioxins (PCDDs), ten polychlorinated dibenzofurans (PCDFs) as well as twelve polychlorinated biphenyls (PCBs) are collectively referred to as dioxin-like compounds. The World Health Organization toxic equivalency factors (TEFs) for these persistent chlorinated organic compounds and their measured concentrations are used to produce the toxic equivalency quotient (TEQ) of a sample. TEF values are partially based on a common mechanism involving binding of the chemical to the aryl hydrocarbon receptor (AhR). Biological methods for the determination of TEQs are based on the assumption that all dioxin-related compounds act through the Ah receptor signal transduction pathway. Based on the biochemical response of CYP1A activation via the AhR, in vitro systems that utilize a reporter gene under transcriptional control of CYP1A have been developed. Several investigations have reported on the success of utilizing biological test systems to detect PCDDs, PCDFs, PCBs in environmental samples. The P450 Human Reporter Gene System assay (EPA Method 4425) utilizes a human hepatoma cell line (HepG2) in which a plasmid containing the human CYP1A1 promoter and 5'-flanking sequences with three xenobiotic responsive elements (XREs) fused to the luciferase reporter gene. The enzyme luciferase is produced in the presence of compounds that bind the XREs, and can be detected by a simple assay that measures relative light units with a luminometer. Method 4425, used by Columbia Analytical Services (CAS), has gained acceptance as a rapid and inexpensive approach for screening solvent extracts of environmental samples of soil, sediment, tissue, and water to detect compounds that activate the AhR. Investigations in the U. S. and Japan comparing the results of 4425 and standard high-resolution GC/MS (HRGC/HRMS) will be reported here. The purpose of making these comparisons is to determine if risk assessments for large dioxin sites both before and after remediation

  7. Design and Characterization of a Lens TEM Horn

    NASA Astrophysics Data System (ADS)

    Bigelow, W. S.; Farr, E. G.; Bowen, L. H.; Ellibee, D. E.; Lawry, D. I.

    We investigate an approach for obtaining smaller UWB antennas with lower sidelobes than those offered by current designs. In support of this, we built and tested a lens TEM horn employing a collimating polyethylene aperture lens. It was thought that the lens TEM horn, with a more uniformly illuminated aperture field, might lead to higher gain with lower sidelobes than a comparably sized reflector IRA. That hypothesis is tested here. The lens horn, with a 30-cm aperture, has a maximum realized gain on boresight of 23 dB at 10 GHz. The normalized antenna impulse response is a clean peak with a full-width-at-half-maximum (FWHM) of 35 ps. For comparison, a highly optimized reflector IRA with 46-cm diameter achieves a maximum realized gain of 28 dB at 19 GHz and an impulse response with a FWHM of 30 ps. From theory, we expected the lens horn to exhibit lower sidelobes than the IRA. However, we did not observe that behavior in our experimental model. We suggest refinements which might lead to reduced sidelobes and increased gain in lens TEM horns.

  8. Design of a TEM cell EMP simulator

    NASA Astrophysics Data System (ADS)

    Sevat, Pete

    1991-06-01

    Electromagnetic pulse (EMP) simulators are designed to simulate the EMP generated by a nuclear weapon and are used to harden equipment against the effects of EMP. A transverse electromagnetic (TEM) cell is a square or rectangular coaxial transmission line tapered at each end to form a closed cell. The cell is fed at one end with a signal generator, a continuous wave or pulse generator, and terminated at the other end with a resistor equal to the characteristic impedance of the line. An advantage of the TEM cell is that the field is well characterized and reasonably uniform. A small, symmetric, TEM cell EMP simulator is described which is intended for applications such as susceptibility testing of small equipment, calibration of sensors, design and testing of countermeasures, measurement of transfer functions, and research and development. A detailed design is presented for a 50 ohm and 100 ohm TEM cell with an inner volume of 4 m(exp 3) and a test volume of 0.24 m(exp 3). The pulse generator and terminating network are integrated into the cell to form a completely shielded structure. In this way no interference from the inside of the cell to the outside, or vice versa, will occur.

  9. Silver Trees: Chemistry on a TEM Grid

    EPA Science Inventory

    The copper/carbon substrate of a TEM grid reacted with aqueous silver nitrate solution within minutes to yield spectacular tree-like silver dendrites, without using any added capping or reducing reagents. These results demonstrate a facile, aqueous, room temperature synthesis of...

  10. Test for English Majors (TEM) in China

    ERIC Educational Resources Information Center

    Jin, Yan; Fan, Jinsong

    2011-01-01

    The purpose of the Test for English Majors (TEM) is to measure the English proficiency of Chinese university undergraduates majoring in English Language and Literature and to examine whether these students meet the required levels of English language abilities as specified in the National College English Teaching Syllabus for English Majors…

  11. Silver Trees: Chemistry on a TEM Grid

    EPA Science Inventory

    The copper/carbon substrate of a TEM grid reacted with aqueous silver nitrate solution within minutes to yield spectacular tree-like silver dendrites, without using any added capping or reducing reagents. These results demonstrate a facile, aqueous, room temperature synthesis of...

  12. Replica extraction method on nanostructured gold coatings and orientation determination combining SEM and TEM techniques.

    PubMed

    Bocker, Christian; Kracker, Michael; Rüssel, Christian

    2014-12-01

    In the field of electron microscopy the replica technique is known as an indirect method and also as an extraction method that is usually applied on metallurgical samples. This contribution describes a fast and simple transmission electron microscopic (TEM) sample preparation by complete removal of nanoparticles from a substrate surface that allows the study of growth mechanisms of nanostructured coatings. The comparison and combination of advanced diffraction techniques in the TEM and scanning electron microscopy (SEM) provide possibilities for operators with access to both facilities. The analysis of TEM-derived diffraction patterns (convergent beam electron diffraction) in the SEM/electron backscatter diffraction software simplifies the application, especially when the patterns are not aligned along a distinct zone axis. The study of the TEM sample directly by SEM and transmission Kikuchi diffraction allows cross-correlation with the TEM results.

  13. Monitoring the Stability of Perfluorocarbon Nanoemulsions by Cryo-TEM Image Analysis and Dynamic Light Scattering

    PubMed Central

    Grapentin, Christoph; Barnert, Sabine; Schubert, Rolf

    2015-01-01

    Perfluorocarbon nanoemulsions (PFC-NE) are disperse systems consisting of nanoscale liquid perfluorocarbon droplets stabilized by an emulsifier, usually phospholipids. Perfluorocarbons are chemically inert and non-toxic substances that are exhaled after in vivo administration. The manufacture of PFC-NE can be done in large scales by means of high pressure homogenization or microfluidization. Originally investigated as oxygen carriers for cases of severe blood loss, their application nowadays is more focused on using them as marker agents in 19F Magnetic Resonance Imaging (19F MRI). 19F is scarce in organisms and thus PFC-NE are a promising tool for highly specific and non-invasive imaging of inflammation via 19F MRI. Neutrophils, monocytes and macrophages phagocytize PFC-NE and subsequently migrate to inflamed tissues. This technique has proven feasibility in numerous disease models in mice, rabbits and mini pigs. The translation to clinical trials in human needs the development of a stable nanoemulsion whose droplet size is well characterized over a long storage time. Usually dynamic light scattering (DLS) is applied as the standard method for determining particle sizes in the nanometer range. Our study uses a second method, analysis of transmission electron microscopy images of cryo-fixed samples (Cryo-TEM), to evaluate stability of PFC-NE in comparison to DLS. Four nanoemulsions of different composition are observed for one year. The results indicate that DLS alone cannot reveal the changes in particle size, but can even mislead to a positive estimation of stability. The combination with Cryo-TEM images gives more insight in the particulate evolution, both techniques supporting one another. The study is one further step in the development of analytical tools for the evaluation of a clinically applicable perfluorooctylbromide nanoemulsion. PMID:26098661

  14. Final report on EURAMET.QM-S9/1212: Supplementary comparison of analytical capabilities for synthetic natural gas

    NASA Astrophysics Data System (ADS)

    Valková, M.; Mirt, M.; Beranek, J.; Bárta, M.; Žamberova, I.; van der Veen, A. M. H.; Ziel, P. R.; Augusto, C. R.; Ribeiro, C. C.; Teixeira, D. C. G. S.; Oudwater, R. J.

    2014-01-01

    The EURAMET supplementary comparison EURAMET.QM-S9 involves standard gas mixtures of synthetic natural gas. It is similar to key comparison CCQM-K16 (2001-2002). Analysed were gas mixtures of synthetic natural gas containing nitrogen, carbon dioxide and the alkanes up to hexane with a total of 10 components. Four laboratories (CMI, Czech Republic; INMETRO, Brazil; SMU, Slovakia; and VSL, The Netherlands) participated in this supplementary comparison. All of the participants, except CMI, have established facilities for natural gas analysis, and have existing claims for their Calibration and Measurement Capabilities (CMCs) for natural gas mixtures. The agreement of the results in this supplementary comparison is very good. All the results with their reported uncertainties are in agreement with the reference values for all the participants. SMU and VSL participated in the key comparison CCQM-K16. VSL obtained very good results in both the supplementary comparison and the CCQM-K16 comparison. SMU obtained better results in the supplementary comparison than in CCQM-K16. Main text. To reach the main text of this paper, click on Final Report. The final report has been peer-reviewed and approved for publication by the CCQM.

  15. LLNL Workshop on TEM of Pu

    SciTech Connect

    King, W.E.

    1996-09-10

    On Sept. 10, 1996, LLNL hosted a workshop aimed at answering the question: Is it possible to carry out transmission electron microscopy (TEM) on plutonium metal in an electron microscope located outside the LLNL plutonium facility. The workshop focused on evaluation of a proposed plan for Pu microscopy both from a technical and environment, health, and safety point of view. After review and modification of the plan, workshop participants unanimously concluded that: (1) the technical plan is sound, (2) this technical plan, including a proposal for a new TEM, provides significant improvements and unique capabilities compared with the effort at LANL and is therefore complementary, (3) there is no significant environment, health, and safety obstacle to this plan.

  16. Quantification of small, convex particles by TEM.

    PubMed

    Andersen, Sigmund J; Holme, Børge; Marioara, Calin D

    2008-07-01

    It is shown how size distributions of arbitrarily oriented, convex, non-overlapping particles extracted from conventional transmission electron microscopy (TEM) images may be determined by a variation of the Schwartz-Saltykov method. In TEM, particles cut at the surfaces have diminished projections, which alter the observed size distribution. We represent this distribution as a vector and multiply it with the inverse of a matrix comprising thickness-dependent Scheil or Schwartz-Saltykov terms. The result is a corrected size distribution of the projections of uncut particles. It is shown how the real (3D) distribution may be estimated when particle shape is considered. Computer code to generate the matrix is given. A log-normal distribution of spheres and a real distribution of pill-box-shaped dispersoids in an Al-Mg-Si alloy are given as examples. The errors are discussed in detail.

  17. Whispering gallery modes at the rim of an axisymmetric optical resonator: analytical versus numerical description and comparison with experiment.

    PubMed

    Breunig, I; Sturman, B; Sedlmeir, F; Schwefel, H G L; Buse, K

    2013-12-16

    Optical whispering gallery modes (WGMs) of mm-sized axisymmetric resonators are well localized at the equator. Employing this distinctive feature, we obtain simple analytical relations for the frequencies and eigenfunctions of WGMs which include the major radius of the resonator and the curvature radius of the rim. Being compared with results of finite-element simulations, these relations show a high accuracy and practicability. High-precision free-spectral-range measurements with a millimeter-sized disc resonator made of MgF(2) allow us to identify the WGMs and confirm the applicability of our analytical description.

  18. Radial averages of astigmatic TEM images.

    PubMed

    Fernando, K Vince

    2008-10-01

    The Contrast Transfer Function (CTF) of an image, which modulates images taken from a Transmission Electron Microscope (TEM), is usually determined from the radial average of the power spectrum of the image (Frank, J., Three-dimensional Electron Microscopy of Macromolecular Assemblies, Oxford University Press, Oxford, 2006). The CTF is primarily defined by the defocus. If the defocus estimate is accurate enough then it is possible to demodulate the image, which is popularly known as the CTF correction. However, it is known that the radial average is somewhat attenuated if the image is astigmatic (see Fernando, K.V., Fuller, S.D., 2007. Determination of astigmatism in TEM images. Journal of Structural Biology 157, 189-200) but this distortion due to astigmatism has not been fully studied or understood up to now. We have discovered the exact mathematical relationship between the radial averages of TEM images with and without astigmatism. This relationship is determined by a zeroth order Bessel function of the first kind and hence we can exactly quantify this distortion in the radial averages of signal and power spectra of astigmatic images. The argument to this Bessel function is similar to an aberration function (without the spherical aberration term) except that the defocus parameter is replaced by the differences of the defoci in the major and minor axes of astigmatism. The ill effects due this Bessel function are twofold. Since the zeroth order Bessel function is a decaying oscillatory function, it introduces additional zeros to the radial average and it also attenuates the CTF signal in the radial averages. Using our analysis, it is possible to simulate the effects of astigmatism in radial averages by imposing Bessel functions on idealized radial averages of images which are not astigmatic. We validate our theory using astigmatic TEM images.

  19. Novel TEM-type extended-spectrum beta-lactamase, TEM-134, in a Citrobacter koseri clinical isolate.

    PubMed

    Perilli, Mariagrazia; Mugnaioli, Claudia; Luzzaro, Francesco; Fiore, Marianna; Stefani, Stefania; Rossolini, Gian Maria; Amicosante, Gianfranco

    2005-04-01

    A new natural TEM derivative with extended-spectrum beta-lactamase activity, TEM-134, was identified in a ceftazidime-resistant clinical isolate of Citrobacter koseri. Compared to TEM-1, TEM-134 contains the following mutations: Q39K, E104K, R164H, and G238S. The bla(TEM-134) gene was not transferable by conjugation and, apparently, was chromosomally encoded. Expression studies with Escherichia coli revealed efficient cefotaximase and ceftazidimase activity for TEM-134.

  20. A TEM analysis of nanoparticulates in a Polar ice core

    SciTech Connect

    Esquivel, E.V.; Murr, L.E

    2004-03-15

    This paper explores the prospect for analyzing nanoparticulates in age-dated ice cores representing times in antiquity to establish a historical reference for atmospheric particulate regimes. Analytical transmission electron microscope (TEM) techniques were utilized to observe representative ice-melt water drops dried down on carbon/formvar or similar coated grids. A 10,000-year-old Greenland ice core was melted, and representative water drops were transferred to coated grids in a clean room environment. Essentially, all particulates observed were aggregates and either crystalline or complex mixtures of nanocrystals. Especially notable was the observation of carbon nanotubes and related fullerene-like nanocrystal forms. These observations are similar with some aspects of contemporary airborne particulates including carbon nanotubes and complex nanocrystal aggregates.

  1. Estimating the Coefficient of Cross-validity in Multiple Regression: A Comparison of Analytical and Empirical Methods.

    ERIC Educational Resources Information Center

    Kromrey, Jeffrey D.; Hines, Constance V.

    1996-01-01

    The accuracy of three analytical formulas for shrinkage estimation and four empirical techniques were investigated in a Monte Carlo study of the coefficient of cross-validity in multiple regression. Substantial statistical bias was evident for all techniques except the formula of M. W. Brown (1975) and multicross-validation. (SLD)

  2. The analytic element method for rectangular gridded domains, benchmark comparisons and application to the High Plains Aquifer

    USDA-ARS?s Scientific Manuscript database

    Groundwater studies face computational limitations when providing local detail (such as well drawdown) within regional models. We adapt the Analytic Element Method (AEM) to extend separation of variable solutions for a rectangle to domains composed of multiple interconnected rectangular elements. Ea...

  3. Pericenter precession induced by a circumstellar disk on the orbit of massive bodies: comparison between analytical predictions and numerical results

    NASA Astrophysics Data System (ADS)

    Fontana, A.; Marzari, F.

    2016-05-01

    Context. Planetesimals and planets embedded in a circumstellar disk are dynamically perturbed by the disk gravity. It causes an apsidal line precession at a rate that depends on the disk density profile and on the distance of the massive body from the star. Aims: Different analytical models are exploited to compute the precession rate of the perihelion ϖ˙. We compare them to verify their equivalence, in particular after analytical manipulations performed to derive handy formulas, and test their predictions against numerical models in some selected cases. Methods: The theoretical precession rates were computed with analytical algorithms found in the literature using the Mathematica symbolic code, while the numerical simulations were performed with the hydrodynamical code FARGO. Results: For low-mass bodies (planetesimals) the analytical approaches described in Binney & Tremaine (2008, Galactic Dynamics, p. 96), Ward (1981, Icarus, 47, 234), and Silsbee & Rafikov (2015a, ApJ, 798, 71) are equivalent under the same initial conditions for the disk in terms of mass, density profile, and inner and outer borders. They also match the numerical values computed with FARGO away from the outer border of the disk reasonably well. On the other hand, the predictions of the classical Mestel disk (Mestel 1963, MNRAS, 126, 553) for disks with p = 1 significantly depart from the numerical solution for radial distances beyond one-third of the disk extension because of the underlying assumption of the Mestel disk is that the outer disk border is equal to infinity. For massive bodies such as terrestrial and giant planets, the agreement of the analytical approaches is progressively poorer because of the changes in the disk structure that are induced by the planet gravity. For giant planets the precession rate changes sign and is higher than the modulus of the theoretical value by a factor ranging from 1.5 to 1.8. In this case, the correction of the formula proposed by Ward (1981) to

  4. E240V substitution increases catalytic efficiency toward ceftazidime in a new natural TEM-type extended-spectrum beta-lactamase, TEM-149, from Enterobacter aerogenes and Serratia marcescens clinical isolates.

    PubMed

    Perilli, Mariagrazia; Celenza, Giuseppe; De Santis, Francesca; Pellegrini, Cristina; Forcella, Chiara; Rossolini, Gian Maria; Stefani, Stefania; Amicosante, Gianfranco

    2008-03-01

    The aim of this study was to characterize a novel extended-spectrum beta-lactamase that belongs to the TEM family, the TEM-149 enzyme, and that was isolated from the urine of two hospitalized patients from different hospitals in southern Italy. The peculiarity of this enzyme was the finding of a valine residue at position 240. The array of amino acid substitutions found in TEM-149 was as follows: E104K, R164S, M182T, and E240V. A reversion of a threonine residue at position 182 was also performed to create a new mutant, TEM-149 T182M, in order to assess the contribution of this substitution on the kinetic profile and the stability of TEM-149. The bla TEM-149 and bla TEM-149/T182M genes were cloned into pBC-SK, and the corresponding enzymes were purified from recombinant Escherichia coli HB101 by the same procedure. Both enzymes hydrolyzed all beta-lactams tested, with a preference for ceftazidime, which was found to be the best substrate. By comparison of the kinetic parameters of the TEM-149 and the TEM-149 T182M enzymes, a reduction of the catalytic efficiency for the TEM-149 T182M mutant was observed against all substrates tested except benzylpenicillin, cefotaxime, and aztreonam. Tazobactam, clavulanic acid, and sulbactam were good inhibitors of the TEM-149 beta-lactamase.

  5. Technical note: Determination of acidity in whole raw milk: comparison of results obtained by two different analytical methods.

    PubMed

    Fabro, M A; Milanesio, H V; Robert, L M; Speranza, J L; Murphy, M; Rodríguez, G; Castañeda, R

    2006-03-01

    In Argentina, one analytical method is usually carried out to determine acidity in whole raw milk: the Instituto Nacional de Racionalización de Materiales standard (no. 14005), based on the Dornic method of French origin. In a national and international regulation, the Association of Official Analytical Chemists International method (no. 947.05) is proposed as the standard method of analysis. Although these methods have the same foundation, there is no evidence that results obtained using the 2 methods are equivalent. The presence of some trends and discordant data lead us to perform a statistical study to verify the equivalency of the obtained results. We analyzed 266 samples and the existence of significant differences between the results obtained by both methods was determined.

  6. Light Scattering by Coated Sphere Immersed in Absorbing Medium: A Comparison between the FDTD and Analytic Solutions

    NASA Technical Reports Server (NTRS)

    Sun, W.; Loeb, N. G.; Fu, Q.

    2004-01-01

    A recently developed finite-difference time domain scheme is examined using the exact analytic solutions for light scattering by a coated sphere immersed in an absorbing medium. The relative differences are less than 1% in the extinction, scattering, and absorption efficiencies and less than 5% in the scattering phase functions. The definition of apparent single-scattering properties is also discussed. (C) 2003 Elsevier Ltd. All rights reserved.

  7. Light Scattering by Coated Sphere Immersed in Absorbing Medium: A Comparison between the FDTD and Analytic Solutions

    NASA Technical Reports Server (NTRS)

    Sun, W.; Loeb, N. G.; Fu, Q.

    2004-01-01

    A recently developed finite-difference time domain scheme is examined using the exact analytic solutions for light scattering by a coated sphere immersed in an absorbing medium. The relative differences are less than 1% in the extinction, scattering, and absorption efficiencies and less than 5% in the scattering phase functions. The definition of apparent single-scattering properties is also discussed. (C) 2003 Elsevier Ltd. All rights reserved.

  8. Looped ends versus open ends braided stent: A comparison of the mechanical behaviour using analytical and numerical methods.

    PubMed

    Shanahan, Camelia; Tiernan, Peter; Tofail, Syed A M

    2017-08-24

    The present study has two major purposes: firstly, to investigate whether the analytical model proposed by Jedwab and Clerc for assessing the mechanical behaviour of an open ends metallic braided stent is applicable to the looped ends stent design and secondly, to compare the response of the two stent designs subjected to radial compression. We use finite element analysis to evaluate the performance of the two braided stents emulating well established designs: WALLSTENT and WallFlex. We validate the WALLSTENT model analytically. We perform a radial crimping simulation and evaluate the radial forces and stresses induced. This study confirms the validity of using the analytical model in the biomechanical analysis of the WALLSTENT design. However, in case of the WallFlex design, a major difference in the results can be observed in the levels of radial forces and wire peak stresses, justifying the decision of using a different alloy in the fabrication of the WallFlex design. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. On the Multilevel Nature of Meta-Analysis: A Tutorial, Comparison of Software Programs, and Discussion of Analytic Choices.

    PubMed

    Pastor, Dena A; Lazowski, Rory A

    2017-09-27

    The term "multilevel meta-analysis" is encountered not only in applied research studies, but in multilevel resources comparing traditional meta-analysis to multilevel meta-analysis. In this tutorial, we argue that the term "multilevel meta-analysis" is redundant since all meta-analysis can be formulated as a special kind of multilevel model. To clarify the multilevel nature of meta-analysis the four standard meta-analytic models are presented using multilevel equations and fit to an example data set using four software programs: two specific to meta-analysis (metafor in R and SPSS macros) and two specific to multilevel modeling (PROC MIXED in SAS and HLM). The same parameter estimates are obtained across programs underscoring that all meta-analyses are multilevel in nature. Despite the equivalent results, not all software programs are alike and differences are noted in the output provided and estimators available. This tutorial also recasts distinctions made in the literature between traditional and multilevel meta-analysis as differences between meta-analytic choices, not between meta-analytic models, and provides guidance to inform choices in estimators, significance tests, moderator analyses, and modeling sequence. The extent to which the software programs allow flexibility with respect to these decisions is noted, with metafor emerging as the most favorable program reviewed.

  10. Application of surface plasmon resonance for the detection of carbohydrates, glycoconjugates, and measurement of the carbohydrate-specific interactions: a comparison with conventional analytical techniques. A critical review.

    PubMed

    Safina, Gulnara

    2012-01-27

    Carbohydrates (glycans) and their conjugates with proteins and lipids contribute significantly to many biological processes. That makes these compounds important targets to be detected, monitored and identified. The identification of the carbohydrate content in their conjugates with proteins and lipids (glycoforms) is often a challenging task. Most of the conventional instrumental analytical techniques are time-consuming and require tedious sample pretreatment and utilising various labeling agents. Surface plasmon resonance (SPR) has been intensively developed during last two decades and has received the increasing attention for different applications, from the real-time monitoring of affinity bindings to biosensors. SPR does not require any labels and is capable of direct measurement of biospecific interaction occurring on the sensing surface. This review provides a critical comparison of modern analytical instrumental techniques with SPR in terms of their analytical capabilities to detect carbohydrates, their conjugates with proteins and lipids and to study the carbohydrate-specific bindings. A few selected examples of the SPR approaches developed during 2004-2011 for the biosensing of glycoforms and for glycan-protein affinity studies are comprehensively discussed.

  11. Comparison of analytical and predictive methods for water, protein, fat, sugar, and gross energy in marine mammal milk.

    PubMed

    Oftedal, O T; Eisert, R; Barrell, G K

    2014-01-01

    Mammalian milks may differ greatly in composition from cow milk, and these differences may affect the performance of analytical methods. High-fat, high-protein milks with a preponderance of oligosaccharides, such as those produced by many marine mammals, present a particular challenge. We compared the performance of several methods against reference procedures using Weddell seal (Leptonychotes weddellii) milk of highly varied composition (by reference methods: 27-63% water, 24-62% fat, 8-12% crude protein, 0.5-1.8% sugar). A microdrying step preparatory to carbon-hydrogen-nitrogen (CHN) gas analysis slightly underestimated water content and had a higher repeatability relative standard deviation (RSDr) than did reference oven drying at 100°C. Compared with a reference macro-Kjeldahl protein procedure, the CHN (or Dumas) combustion method had a somewhat higher RSDr (1.56 vs. 0.60%) but correlation between methods was high (0.992), means were not different (CHN: 17.2±0.46% dry matter basis; Kjeldahl 17.3±0.49% dry matter basis), there were no significant proportional or constant errors, and predictive performance was high. A carbon stoichiometric procedure based on CHN analysis failed to adequately predict fat (reference: Röse-Gottlieb method) or total sugar (reference: phenol-sulfuric acid method). Gross energy content, calculated from energetic factors and results from reference methods for fat, protein, and total sugar, accurately predicted gross energy as measured by bomb calorimetry. We conclude that the CHN (Dumas) combustion method and calculation of gross energy are acceptable analytical approaches for marine mammal milk, but fat and sugar require separate analysis by appropriate analytic methods and cannot be adequately estimated by carbon stoichiometry. Some other alternative methods-low-temperature drying for water determination; Bradford, Lowry, and biuret methods for protein; the Folch and the Bligh and Dyer methods for fat; and enzymatic and reducing

  12. Analytical and numerical quantification and comparison of the local electric field in the tissue for different electrode configurations

    PubMed Central

    Čorović, Selma; Pavlin, Mojca; Miklavčič, Damijan

    2007-01-01

    Background Electrochemotherapy and gene electrotransfer are novel promising treatments employing locally applied high electric pulses to introduce chemotherapeutic drugs into tumor cells or genes into target cells based on the cell membrane electroporation. The main focus of this paper was to calculate analytically and numerically local electric field distribution inside the treated tissue in two dimensional (2D) models for different plate and needle electrode configurations and to compare the local electric field distribution to parameter U/d, which is widely used in electrochemotherapy and gene electrotransfer studies. We demonstrate the importance of evaluating the local electric field distribution in electrochemotherapy and gene electrotransfer. Methods We analytically and numerically analyze electric field distribution based on 2D models for electrodes and electrode configurations which are most widely used in electrochemotherapy and gene electrotransfer. Analytical calculations were performed by solving the Laplace equation and numerical calculations by means of finite element method in two dimensions. Results We determine the minimal and maximal E inside the target tissue as well as the maximal E over the entire treated tissue for the given electrode configurations. By comparing the local electric field distribution calculated for different electrode configurations to the ratio U/d, we show that the parameter U/d can differ significantly from the actual calculated values of the local electric field inside the treated tissue. By calculating the needed voltage to obtain E > U/d inside the target tissue, we showed that better electric field distribution can be obtained by increasing the number and changing the arrangement of the electrodes. Conclusion Based on our analytical and numerical models of the local electric field distribution we show that the applied voltage, configuration of the electrodes and electrode position need to be chosen specifically for

  13. Web Analytics

    EPA Pesticide Factsheets

    EPA’s Web Analytics Program collects, analyzes, and provides reports on traffic, quality assurance, and customer satisfaction metrics for EPA’s website. The program uses a variety of analytics tools, including Google Analytics and CrazyEgg.

  14. Graphene nanoscrolls and live TEM imaging

    NASA Astrophysics Data System (ADS)

    Mokkapati, Venkata; Mirsaidov, Utkur; Matsudaira, Paul; Oezyilmaz, Barbaros; Graphene research laboratory Team; Centerbio-imaging sciences/Mechanobiology institute Team

    2013-03-01

    It has been theoretically hypothesized and predicted that graphene when in contact with water, wraps itself around the droplets and forms graphene nanoscrolls. Studying the applications of these nanoscrolls can open a new area of research especially in the bio-medical field. Here we present a method where partially suspended graphene nanoscrolls were fabricated on carbon mesh attached to a gold TEM grid. The process involves sandwiching of two graphene layers with water being encapsulated within these nanoscrolls. Gold nanoparticles were encapsulated and live imaging of water and gold nanoparticles was carried out under the TEM. The dynamics of the encapsulated water and nanobubbles is being studied. The encapsulated water within these graphene nanoscrolls lasted for more than three months (till the date of publication). It was also realized that the formation/abundance of these nanoscrolls is concentration dependent of the etching solution (Ammonium persulfate) with a saturation point. Large area, uniform, monolayer graphene films can also be produced by varying the concentration of Ammonium persulfate. Further studies are being carried out to live image TMV/protein and liposome encapsulated drugs using nanoscrolls and films respectively. The authors would like to acknowledge A*Star for funding this research

  15. Technical Evaluation Motor 3 (TEM-3)

    NASA Technical Reports Server (NTRS)

    Garecht, Diane

    1989-01-01

    A primary objective of the technical evaluation motor program is to recover the case, igniter and nozzle hardware for use on the redesigned solid rocket motor flight program. Two qualification objectives were addressed and met on TEM-3. The Nylok thread locking device of the 1U100269-03 leak check port plug and the 1U52295-04 safe and arm utilizing Krytox grease on the barrier-booster shaft O-rings were both certified. All inspection and instrumentation data indicate that the TEM-3 static test firing conducted 23 May 1989 was successful. The test was conducted at ambient conditions with the exception of the field joints (set point of 121 F, with a minimum of 87 F at the sensors), igniter joint (set point at 122 F with a minimum of 87 F at sensors) and case-to-nozzle joint (set point at 114 F with a minimum of 87 F at sensors). Ballistics performance values were within specification requirements. Nozzle performance was nominal with typical erosion. The nozzle and the case joint temperatures were maintained at the heaters controlling set points while electrical power was supplied. The water and the CO2 quench systems prevented damage to the metal hardware. All other test equipment performed as planned, contributing to a successful motor firing. All indications are that the test was a success, and all expected hardware will be refurbished for the RSRM program.

  16. TEM investigations on the local microstructure of electrodeposited galfenol nanowires

    NASA Astrophysics Data System (ADS)

    Pohl, D.; Damm, C.; Pohl, D.; Schultz, L.; Schlörb, H.

    2016-01-01

    The local microstructure of Fe-Ga nanowires is investigated considering dependence on the deposition technique. Using a complexed electrolyte, smooth and homogeneous Fe80Ga20 nanowires are deposited into anodic aluminum oxide templates by either applying pulse potential or potentiostatic deposition technique. At optimized deposition conditions the wires show the desired composition of Fe80±2Ga20±2 without a gradient along the growth direction. Composition distribution, structure and microstructure are examined in detail and reveal only minor differences. Line EELS and crystal lattice measurements reveal a negligible oxygen content for both preparation routines. Neither Fe/Ga oxides nor hydroxides were found. Both potentiostatically deposited as well as pulse deposited nanowires exhibit a preferred <110> orientation, the latter with slightly larger crystals. Different contrast patterns were found by TEM that appear more pronounced in the case of pulse deposited wires. High resolution transmission electron microscopy analysis and comparison of differently prepared focused ion beam lamellas reveal that these contrasts are caused by defects in the alternating potential deposition itself and are not induced during the TEM preparation process. The alternating potential mode causes periodic growth thereby inducing different layers with reduced wire thickness/defects at the layer interfaces.

  17. Positional correlative anatomy of invertebrate model organisms increases efficiency of TEM data production.

    PubMed

    Kolotuev, Irina

    2014-10-01

    Transmission electron microscopy (TEM) is an important tool for studies in cell biology, and is essential to address research questions from bacteria to animals. Recent technological innovations have advanced the entire field of TEM, yet classical techniques still prevail for most present-day studies. Indeed, the majority of cell and developmental biology studies that use TEM do not require cutting-edge methodologies, but rather fast and efficient data generation. Although access to state-of-the-art equipment is frequently problematic, standard TEM microscopes are typically available, even in modest research facilities. However, a major unmet need in standard TEM is the ability to quickly prepare and orient a sample to identify a region of interest. Here, I provide a detailed step-by-step method for a positional correlative anatomy approach to flat-embedded samples. These modifications make the TEM preparation and analytic procedures faster and more straightforward, supporting a higher sampling rate. To illustrate the modified procedures, I provide numerous examples addressing research questions in Caenorhabditis elegans and Drosophila. This method can be equally applied to address questions of cell and developmental biology in other small multicellular model organisms.

  18. Comparison of Cluster, Slab, and Analytic Potential Models for the Dimethyl Methylphosphonate (DMMP)/TiO2 (110) Intermolecular Interaction

    SciTech Connect

    Yang, Li; Tunega, Daniel; Xu, Lai; Govind, Niranjan; Sun, Rui; Taylor, Ramona; Lischka, Hans; De Jong, Wibe A.; Hase, William L.

    2013-08-29

    In a previous study (J. Phys. Chem. C 2011, 115, 12403) cluster models for the TiO2 rutile (110) surface and MP2 calculations were used to develop an analytic potential energy function for dimethyl methylphosphonate (DMMP) interacting with this surface. In the work presented here, this analytic potential and MP2 cluster models are compared with DFT "slab" calculations for DMMP interacting with the TiO2 (110) surface and with DFT cluster models for the TiO2 (110) surface. The DFT slab calculations were performed with the PW91 and PBE functionals. The analytic potential gives DMMP/ TiO2 (110) potential energy curves in excellent agreement with those obtained from the slab calculations. The cluster models for the TiO2 (110) surface, used for the MP2 calculations, were extended to DFT calculations with the B3LYP, PW91, and PBE functional. These DFT calculations do not give DMMP/TiO2 (110) interaction energies which agree with those from the DFT slab calculations. Analyses of the wave functions for these cluster models show that they do not accurately represent the HOMO and LUMO for the surface, which should be 2p and 3d orbitals, respectively, and the models also do not give an accurate band gap. The MP2 cluster models do not accurately represent the LUMO and that they give accurate DMMP/TiO2 (110) interaction energies is apparently fortuitous, arising from their highly inaccurate band gaps. Accurate cluster models, consisting of 7, 10, and 15 Ti-atoms and which have the correct HOMO and LUMO properties, are proposed. The work presented here illustrates the care that must be taken in "constructing" cluster models which accurately model surfaces.

  19. Fatty acid desaturation index in human plasma: comparison of different analytical methodologies for the evaluation of diet effects.

    PubMed

    Klawitter, Jost; Bek, Stephan; Zakaria, Marjorie; Zeng, Chenhui; Hornberger, Andrea; Gilbert, Richard; Shokati, Touraj; Klawitter, Jelena; Christians, Uwe; Boernsen, K Olaf

    2014-10-01

    Stearoyl-CoA desaturase 1 (SCD1) plays a role in the development of obesity and related conditions, such as insulin resistance, and potentially also in neurological and heart diseases. The activity of SCD1 can be monitored using the desaturation index (DI), the ratio of product (16:1n-7 and 18:1n-9) to precursor (16:0 and 18:0) fatty acids. Here, different analytical strategies were applied to identify the method which best supports SCD1 biology. A novel effective approach was the use of the SCD1-independent fatty acid (16:1n-10) as a negative control. The first approach was based on a simple extraction followed by neutral loss triglyceride fatty acid analysis. The second approach was based on the saponification of triglycerides followed by fatty acid analysis (specific for the position of the double bond within monounsaturated fatty acids (MUFAs)). In addition to the analytical LC-MS assays, different matrices (plasma total triglyceride fraction and the very low-density lipoprotein (VLDL) fraction) were investigated to identify the best for studying changes in SCD1 activity. Samples from volunteers on a high-carbohydrate diet were analyzed. Both ultra HPLC (UHPLC)-MS-based assays showed acceptable accuracies (75-125% of nominal) and precisions (<20%) for the analysis of DI-specific fatty acids in VLDL and plasma. The most specific assay for the analysis of the liver SCD activity was then validated for specificity and selectivity, intra- and interday accuracy and precision, matrix effects, dilution effects, and analyte stability. After 3 days of high-carbohydrate diet, only the specific fatty acids in human plasma VLDL showed a significant increase in DI and associated SCD1 activity.

  20. Structural Response of Fluid Containing Tanks to Penetrating Projectiles (Hydraulic Ram) - A Comparison of Experimental and Analytical Results

    DTIC Science & Technology

    1976-05-01

    HYDRAULIC rA)L - U A COMPARISON OF EXPERIXEMNTAL AND ANATYTICAL RESULTS - R. E. BALL MAY 1976 Approved for public release; distribution unlimited Prepared...2 II. EXPERIMENTAL PROGRAMS . . . . . . . . . . . . . . . . . . . 7 A . Naval Weapons Center Exit Wall Test Program ...... 7 B. Naval...Postgraduate School Entry Wall Test Program .* . 13 III. FLUID-STRUCTURE INTERACTION ... . . . . . . . . . . 16 A . Governing Equations

  1. Power of Latent Growth Modeling for Detecting Linear Growth: Number of Measurements and Comparison with Other Analytic Approaches

    ERIC Educational Resources Information Center

    Fan, Xitao; Fan, Xiaotao

    2005-01-01

    The authors investigated 2 issues concerning the power of latent growth modeling (LGM) in detecting linear growth: the effect of the number of repeated measurements on LGM's power in detecting linear growth and the comparison between LGM and some other approaches in terms of power for detecting linear growth. A Monte Carlo simulation design was…

  2. Power of Latent Growth Modeling for Detecting Linear Growth: Number of Measurements and Comparison with Other Analytic Approaches

    ERIC Educational Resources Information Center

    Fan, Xitao; Fan, Xiaotao

    2005-01-01

    The authors investigated 2 issues concerning the power of latent growth modeling (LGM) in detecting linear growth: the effect of the number of repeated measurements on LGM's power in detecting linear growth and the comparison between LGM and some other approaches in terms of power for detecting linear growth. A Monte Carlo simulation design was…

  3. Investigation and comparison of analytical, numerical, and experimentally measured coupling losses for multi-step index optical fibers.

    PubMed

    Aldabaldetreku, Gotzon; Durana, Gaizka; Zubia, Joseba; Arrue, Jon; Poisel, Hans; Losada, María

    2005-05-30

    The aim of the present paper is to provide a comprehensive analysis of the coupling losses in multi-step index (MSI) fibres. Their light power acceptance properties are investigated to obtain the corresponding analytical expressions taking into account longitudinal, transverse, and angular misalignments. For this purpose, a uniform power distribution is assumed. In addition, we perform several experimental measurements and computer simulations in order to calculate the coupling losses for two different MSI polymer optical fibres (MSI-POFs). These results serve us to validate the theoretical expressions we have obtained.

  4. Transmission Electron Microscopy (TEM) investigations of ancient Egyptian cosmetic powders

    NASA Astrophysics Data System (ADS)

    Deeb, C.; Walter, P.; Castaing, J.; Penhoud, P.; Veyssière, P.

    The processing technologies available during the time of ancient Egypt are of present concern to the field of Archaeology and Egyptology. Materials characterization is the best tool for establishing the processing history of archaeological objects. In this study, transmission electron microscopy (TEM) is used, in addition to other techniques, for phase identification and study of the microstructure and characteristic defect structures in ancient Egyptian cosmetic powders. These powders generally consist of a mix of Pb-containing mineral phases: galena (PbS), cerussite (PbCO3), and phosgenite (Pb2Cl2CO3), among others. Modern materials are fabricated according to recipes found in ancient texts to mimic the processing of ancient times and to compare with the archaeological specimens. In particular, a comparison between the dislocation structures of PbS crystals deformed in the laboratory and PbS from archaeological specimens from the collections of the Louvre Museum is presented .

  5. Analysis of the Tem Mode Linearly Tapered Slot Antenna

    NASA Technical Reports Server (NTRS)

    Janaswamy, R.; Schaubert, D. H.; Pozar, D. M.

    1985-01-01

    The theoretical analysis of the radiation characteristics of the TEM mode Linearly Tapered Slot Antenna (LTSA) is presented. The theory presented is valid for antennas with air dielectric and forms the basis for analysis of the more popular dielectric-supported antennas. The method of analysis involves two steps. In the first step, the aperture distribution in the flared slot is determined. In the second step, the equivalent magnetic current in the slot is treated as radiating in the presence of a conducting half-plane and the far-field components are obtained. Detailed comparison with experiment is made and excellent agreement is obtained. Design curves for the variation of the 3 dB and 10 dB beamwidths as a function of the antenna length, with the flare angle as a parameter, are presented.

  6. Multivariate statistical comparison of analytical procedures for benzene and phenol determination with respect to their environmental impact.

    PubMed

    Tobiszewski, Marek; Tsakovski, Stefan; Simeonov, Vasil; Namieśnik, Jacek

    2014-12-01

    The study describes the possibility of application of self-organizing maps technique to assess the greenness of analytical methodologies. The metrological and "environmental impact" parameters of procedures for benzene and phenol determination in water samples were sets of input data for chemometric analysis. Totally 47 objects and 8 variables formed the data used for analysis. The major factors responsible for non-green character of the methodology are the amount of organic solvent and amount of solid wastes formed. The results of the assessment methods with NEMI symbols and Eco-scale are in good agreement. Greener procedures for benzene and phenol determination are those based on SPME. In case of phenol the methodologies based on GC separation are much greener than those based on LC. The results also show that it is easier to apply green methodologies for benzene, as a compound with lower polarity and hence with less affinity to, than for phenol. The SOM assessment methodology can be useful in choosing the proper analytical procedures.

  7. Comparison of analytical protein separation characteristics for three amine-based capillary-channeled polymer (C-CP) stationary phases.

    PubMed

    Jiang, Liuwei; Marcus, R Kenneth

    2016-02-01

    Capillary-channeled polymer (C-CP) fiber stationary phases are finding utility in the realms of protein analytics as well as downstream processing. We have recently described the modification of poly(ethylene terephthalate) (PET) C-CP fibers to affect amine-rich phases for the weak anion-exchange (WAX) separation of proteins. Polyethylenimine (PEI) is covalently coupled to the PET surface, with subsequent cross-linking imparted by treatment with 1,4-butanediol diglycidyl ether (BUDGE). These modifications yield vastly improved dynamic binding capacities over the unmodified fibers. We have also previously employed native (unmodified) nylon 6 C-CP fibers as weak anion/cation-exchange (mixed-mode) and hydrophobic interaction chromatography (HIC) phases for protein separations. Polyamide, nylon 6, consists of amide groups along the polymer backbone, with primary amines and carboxylic acid end groups. The analytical separation characteristics of these three amine-based C-CP fiber phases are compared here. Each of the C-CP fiber columns in this study was shown to be able to separate a bovine serum albumin/hemoglobin/lysozyme mixture at high mobile phase linear velocity (∼70 mm s(-1)) but with different elution characteristics. These differences reflect the types of protein-surface interactions that are occurring, based on the active group composition of the fiber surfaces. This study provides important fundamental understanding for the development of surface-modified C-CP fiber columns for protein separation.

  8. Sound propagation in dilute suspensions of spheres: Analytical comparison between coupled phase model and multiple scattering theory.

    PubMed

    Valier-Brasier, Tony; Conoir, Jean-Marc; Coulouvrat, François; Thomas, Jean-Louis

    2015-10-01

    Sound propagation in dilute suspensions of small spheres is studied using two models: a hydrodynamic model based on the coupled phase equations and an acoustic model based on the ECAH (ECAH: Epstein-Carhart-Allegra-Hawley) multiple scattering theory. The aim is to compare both models through the study of three fundamental kinds of particles: rigid particles, elastic spheres, and viscous droplets. The hydrodynamic model is based on a Rayleigh-Plesset-like equation generalized to elastic spheres and viscous droplets. The hydrodynamic forces for elastic spheres are introduced by analogy with those of droplets. The ECAH theory is also modified in order to take into account the velocity of rigid particles. Analytical calculations performed for long wavelength, low dilution, and weak absorption in the ambient fluid show that both models are strictly equivalent for the three kinds of particles studied. The analytical calculations show that dilatational and translational mechanisms are modeled in the same way by both models. The effective parameters of dilute suspensions are also calculated.

  9. Comparison of an analytical expression of resin composite curing stresses with in vitro observations of marginal cracking.

    PubMed

    Kahler, Bill; Swain, Michael V; Kotousov, Andrei

    2010-12-01

    To observe the marginal failure at the enamel-resin composite interface upon curing, and utilize a recently developed analytical model for curing stresses to relate to the extent of interfacial failure. Occlusal cavity preparations were restored with Heliomolar, Filtek Z100 or UltraSeal XT Plus resin composites. Teeth were restored with either bulk or incremental placement. The control group was not restored. Teeth were placed in an acrylic ring and embedded in cold mounting epoxy resin and the crown sectioned so that the tooth/restoration interface and cavosurface margin could be visualized with an optical microscope. A recently developed simplified analytical approach was utilized to evaluate the composite-enamel interface tensile stresses for these materials theoretically and thereby the fracture susceptibility of the resin-enamel interface during polymerization. White lines, enamel cracks and interfacial failure of the bond were evident for all three materials evaluated (P < 0.01). Gaps at the enamel-composite interface measured 1-10 microm and were more evident for Ultra Seal XT Plus and Z100 than Heliomolar. Conversely, cracking of the enamel adjacent to the interface was more evident for Heliomolar. Statistical analysis showed that enamel cracking and interfacial failure was significant for all groups (P < 0.01). An inverse relationship was noted between enamel cracking and interfacial failure (P < 0.05). The predictions for the extent of cracking from the mathematical modeling match the experimental data and prior studies.

  10. Analytical and simulation methods for estimating the potential predictive ability of genetic profiling: a comparison of methods and results.

    PubMed

    Kundu, Suman; Karssen, Lennart C; Janssens, A Cecile J W

    2012-12-01

    Various modeling methods have been proposed to estimate the potential predictive ability of polygenic risk variants that predispose to various common diseases. However, it is unknown whether differences between them affect their conclusions on predictive ability. We reviewed input parameters, assumptions and output of the five most common methods and compared their estimates of the area under the receiver operating characteristic (ROC) curve (AUC) using hypothetical data representing effect sizes and frequencies of genetic variants, population disease risk and number of variants. To assess the accuracy of the estimated AUCs, we aimed to reproduce the AUCs of published empirical studies. All methods assumed that the combined effect of genetic variants on disease risk followed a multiplicative risk model of independent genetic effects, but they either assumed per allele, per genotype or dominant/recessive effects for the genetic variants. Modeling strategy and input parameters differed. Methods used simulation analysis or analytical formulas with effect sizes quantified by odds ratios (ORs) or relative risks. Estimated AUC values were similar for lower ORs (<1.2). When AUCs were larger (>0.7) due to variants with strong effects, differences in estimated AUCs between methods increased. The simulation methods accurately reproduced the AUC values of empirical studies, but the analytical methods did not. We conclude that despite differences in input parameters, the modeling methods estimate similar AUC for realistic values of the ORs. When one or more variants have stronger effects and AUC values are higher, the simulation methods tend to be more accurate.

  11. Comparison of the VIMOS-VLT Deep Survey with the Munich semi-analytical model. I. Magnitude counts, redshift distribution, colour bimodality, and galaxy clustering

    NASA Astrophysics Data System (ADS)

    de la Torre, S.; Meneux, B.; De Lucia, G.; Blaizot, J.; Le Fèvre, O.; Garilli, B.; Cucciati, O.; Mellier, Y.; Pollo, A.; Abbas, U.; Bottini, D.; Le Brun, V.; Maccagni, D.; Scodeggio, M.; Tresse, L.; Vettolani, G.; Zanichelli, A.; Adami, C.; Arnouts, S.; Bardelli, S.; Bolzonella, M.; Cappi, A.; Charlot, S.; Ciliegi, P.; Contini, T.; Foucaud, S.; Franzetti, P.; Gavignaud, I.; Guzzo, L.; Ilbert, O.; Iovino, A.; McCracken, H. J.; Marinoni, C.; Mazure, A.; Merighi, R.; Paltani, S.; Pelló, R.; Pozzetti, L.; Vergani, D.; Zamorani, G.; Zucca, E.

    2011-01-01

    Aims: This paper presents a detailed comparison between high-redshift observations from the VIMOS-VLT Deep Survey (VVDS) and predictions from the Munich semi-analytical model of galaxy formation. In particular, we focus this analysis on the magnitude, redshift, and colour distributions of galaxies, as well as their clustering properties. Methods: We constructed 100 quasi-independent mock catalogues, using the output of the semi-analytical model presented in De Lucia & Blaizot (2007, MNRAS, 375, 2). We then applied the same observational selection function of the VVDS-Deep survey, so as to carry out a fair comparison between models and observations. Results: We find that the semi-analytical model reproduces well the magnitude counts in the optical bands. It tends, however, to overpredict the abundance of faint red galaxies, in particular in the i' and z' bands. Model galaxies exhibit a colour bimodality that is only in qualitative agreement with the data. In particular, we find that the model tends to overpredict the number of red galaxies at low redshift and of blue galaxies at all redshifts probed by VVDS-Deep observations, although a large fraction of the bluest observed galaxies is absent from the model. In addition, the model overpredicts by about 14 per cent the number of galaxies observed at 0.2 < z < 1 with IAB < 24. When comparing the galaxy clustering properties, we find that model galaxies are more strongly clustered than observed ones at all redshift from z = 0.2 to z = 2, with the difference being less significant above z ≃ 1. When splitting the samples into red and blue galaxies, we find that the observed clustering of blue galaxies is well reproduced by the model, while red model galaxies are much more clustered than observed ones, being principally responsible for the strong global clustering found in the model. Conclusions: Our results show that the discrepancies between Munich semi-analytical model predictions and VVDS-Deep observations

  12. Analytical Comparisons of Tree Ring Data, Greenland Ice Core Temperatures and Temperature Fluctuations of the Sargasso Sea

    NASA Astrophysics Data System (ADS)

    Otto, James; Roberts, Jim; Dahiya, Jai

    2012-10-01

    Embedded in various events on Earth are data that allow us to map the temperature of the Earth over many years. In this work we have chosen the temperature fluctuations in the Sargasso sea, the changing patterns in tree ring growth and temperature fluctuations in Greenland ice core samples for comparison with a goal to understanding the patterns in global warming. Signatures have been identified that predate the Industrial Revolution, which had been blamed for much of global warming, that indicate that Earth temperatures have enjoyed numerous intervals of both global warming and global cooling. The intention of this work is not to stir controversy but to make comparisons of scientific data and processes rather than rely on popular opinion or deduction by ``experts'' in climatology to explain global warming.

  13. Body image of children and adolescents with chronic illness: a meta-analytic comparison with healthy peers.

    PubMed

    Pinquart, M

    2013-03-01

    This meta-analysis integrates results from 330 studies on differences between body image of children and adolescents with and without chronic physical illness. Young people with a chronic illness had a less positive body image than their healthy peers although the average size of differences was small (g=-.30 standard deviation units). A comparison of diseases showed that young people with obesity (g=-.79), cystic fibrosis (g=-.50), scoliosis (g=-.41), asthma (g=-.37), growth hormone deficits (g=-.35), spina bifida (g=-.23), cancer (g=-.20), and diabetes (g=-.17) evaluated their body less positively than their healthy peers. Furthermore, levels of body dissatisfaction varied by age at onset of the disease, method for assessing body image, ethnicity, year of publication, and comparison group. Recommendations are stated for reducing effects of chronic illness on the body image of people with chronic illness.

  14. Volumetric LiDAR scanning of a wind turbine wake and comparison with a 3D analytical wake model

    NASA Astrophysics Data System (ADS)

    Carbajo Fuertes, Fernando; Porté-Agel, Fernando

    2016-04-01

    A correct estimation of the future power production is of capital importance whenever the feasibility of a future wind farm is being studied. This power estimation relies mostly on three aspects: (1) a reliable measurement of the wind resource in the area, (2) a well-established power curve of the future wind turbines and, (3) an accurate characterization of the wake effects; the latter being arguably the most challenging one due to the complexity of the phenomenon and the lack of extensive full-scale data sets that could be used to validate analytical or numerical models. The current project addresses the problem of obtaining a volumetric description of a full-scale wake of a 2MW wind turbine in terms of velocity deficit and turbulence intensity using three scanning wind LiDARs and two sonic anemometers. The characterization of the upstream flow conditions is done by one scanning LiDAR and two sonic anemometers, which have been used to calculate incoming vertical profiles of horizontal wind speed, wind direction and an approximation to turbulence intensity, as well as the thermal stability of the atmospheric boundary layer. The characterization of the wake is done by two scanning LiDARs working simultaneously and pointing downstream from the base of the wind turbine. The direct LiDAR measurements in terms of radial wind speed can be corrected using the upstream conditions in order to provide good estimations of the horizontal wind speed at any point downstream of the wind turbine. All this data combined allow for the volumetric reconstruction of the wake in terms of velocity deficit as well as turbulence intensity. Finally, the predictions of a 3D analytical model [1] are compared to the 3D LiDAR measurements of the wind turbine. The model is derived by applying the laws of conservation of mass and momentum and assuming a Gaussian distribution for the velocity deficit in the wake. This model has already been validated using high resolution wind-tunnel measurements

  15. Matrix Factorizations at Scale: a Comparison of Scientific Data Analytics in Spark and C+MPI Using Three Case Studies

    SciTech Connect

    Gittens, Alex; Devarakonda, Aditya; Racah, Evan; Ringenburg, Michael; Gerhardt, Lisa; Kottalam, Jey; Liu, Jialin; Maschhoff, Kristyn; Canon, Shane; Chhugani, Jatin; Sharma, Pramod; Yang, Jiyan; Demmel, James; Harrell, Jim; Krishnamurthy, Venkat; Mahoney, Michael; Prabhat, Mr

    2016-05-12

    We explore the trade-offs of performing linear algebra using Apache Spark, compared to traditional C and MPI implementations on HPC platforms. Spark is designed for data analytics on cluster computing platforms with access to local disks and is optimized for data-parallel tasks. We examine three widely-used and important matrix factorizations: NMF (for physical plausibility), PCA (for its ubiquity) and CX (for data interpretability). We apply these methods to 1.6TB particle physics, 2.2TB and 16TB climate modeling and 1.1TB bioimaging data. The data matrices are tall-and-skinny which enable the algorithms to map conveniently into Spark’s data parallel model. We perform scaling experiments on up to 1600 Cray XC40 nodes, describe the sources of slowdowns, and provide tuning guidance to obtain high performance.

  16. Gas chromatography – mass spectrometry of JWH-018 metabolites in urine samples with direct comparison to analytical standards

    PubMed Central

    Emerson, Beth; Durham, Bill; Gidden, Jennifer; Lay, Jackson O.

    2013-01-01

    JWH-018 (1-pentyl-3-(1-naphthoyl)indole) is one of numerous potential aminoalkylindoles contained in products marketed as ‘K2’ or ‘Spice’. Investigation of the urinary metabolites from consumption of these compounds is important because they are banned in the United States and many European countries. An efficient extraction procedure and gas chromatography – mass spectrometry (GC-MS) method were developed for detection of ‘K2’ metabolites in urine from individuals suspected of using these products. Analytical standards were used to elucidate the structure-specific mass spectral fragmentations and retention properties to confirm proposed identifications and support quantitative studies. A procedure for the synthesis of one of these metabolites (5-hydroxypentyl JWH-018) was also developed. Results are comparable to existing LC-MS/MS methods, with the same primary metabolites detected. The specific metabolite hydrolysis products include 4-hydroxpentyl, 5-hydroxypentyl, and N-pentanoic acid derivatives. PMID:23683902

  17. Comparison of experimental results with analytical solutions and two dimensional model of oak drying in an evacuated kiln

    SciTech Connect

    Audebert, P.; Temmar, A.

    1997-05-01

    In continuation of a series of tests, the original results of oak drying in an evacuated kiln are presented here for different plate temperatures and for various pressures in the kiln. These results include more particularly the drying curves, the evolution of temperature, of moisture and of pressure in and on the wood. They evidence the pressure and the levels of temperature occurring in the wood during the drying period. These results also allow the development of two types of drying models: a simple monodimensional model of drying curves from the analytical solutions of the equations of water diffusion in the wood and, moreover, a model, in two dimensions, of temperature, moisture and pressure fields in the wood by applying the finite element method. The boundary conditions of the second model can be fixed with precision thanks to the results of the first model. In both cases, the proposed solutions are justified by experimental results.

  18. Toward Rigorous Idiographic Research in Prevention Science: Comparison Between Three Analytic Strategies for Testing Preventive Intervention in Very Small Samples

    PubMed Central

    Pineo, Thomas Z.; Maldonado Molina, Mildred M.; Lich, Kristen Hassmiller

    2013-01-01

    Psychosocial prevention research lacks evidence from intensive within-person lines of research to understand idiographic processes related to development and response to intervention. Such data could be used to fill gaps in the literature and expand the study design options for prevention researchers, including lower-cost yet rigorous studies (e.g., for program evaluations), pilot studies, designs to test programs for low prevalence outcomes, selective/indicated/ adaptive intervention research, and understanding of differential response to programs. This study compared three competing analytic strategies designed for this type of research: autoregressive moving average, mixed model trajectory analysis, and P-technique. Illustrative time series data were from a pilot study of an intervention for nursing home residents with diabetes (N=4) designed to improve control of blood glucose. A within-person, intermittent baseline design was used. Intervention effects were detected using each strategy for the aggregated sample and for individual patients. The P-technique model most closely replicated observed glucose levels. ARIMA and P-technique models were most similar in terms of estimated intervention effects and modeled glucose levels. However, ARIMA and P-technique also were more sensitive to missing data, outliers and number of observations. Statistical testing suggested that results generalize both to other persons as well as to idiographic, longitudinal processes. This study demonstrated the potential contributions of idiographic research in prevention science as well as the need for simulation studies to delineate the research circumstances when each analytic approach is optimal for deriving the correct parameter estimates. PMID:23299558

  19. Analytic Validation of Immunohistochemical Assays: A Comparison of Laboratory Practices Before and After Introduction of an Evidence-Based Guideline.

    PubMed

    Fitzgibbons, Patrick L; Goldsmith, Jeffrey D; Souers, Rhona J; Fatheree, Lisa A; Volmar, Keith E; Stuart, Lauren N; Nowak, Jan A; Astles, J Rex; Nakhleh, Raouf E

    2017-09-01

    - Laboratories must demonstrate analytic validity before any test can be used clinically, but studies have shown inconsistent practices in immunohistochemical assay validation. - To assess changes in immunohistochemistry analytic validation practices after publication of an evidence-based laboratory practice guideline. - A survey on current immunohistochemistry assay validation practices and on the awareness and adoption of a recently published guideline was sent to subscribers enrolled in one of 3 relevant College of American Pathologists proficiency testing programs and to additional nonsubscribing laboratories that perform immunohistochemical testing. The results were compared with an earlier survey of validation practices. - Analysis was based on responses from 1085 laboratories that perform immunohistochemical staining. Of 1057 responses, 65.4% (691) were aware of the guideline recommendations before this survey was sent and 79.9% (550 of 688) of those have already adopted some or all of the recommendations. Compared with the 2010 survey, a significant number of laboratories now have written validation procedures for both predictive and nonpredictive marker assays and specifications for the minimum numbers of cases needed for validation. There was also significant improvement in compliance with validation requirements, with 99% (100 of 102) having validated their most recently introduced predictive marker assay, compared with 74.9% (326 of 435) in 2010. The difficulty in finding validation cases for rare antigens and resource limitations were cited as the biggest challenges in implementing the guideline. - Dissemination of the 2014 evidence-based guideline validation practices had a positive impact on laboratory performance; some or all of the recommendations have been adopted by nearly 80% of respondents.

  20. Tidally averaged circulation in Puget Sound sub-basins: Comparison of historical data, analytical model, and numerical model

    SciTech Connect

    Khangaonkar, Tarang; Yang, Zhaoqing; Kim, Tae Yun; Roberts, Mindy

    2011-07-20

    Through extensive field data collection and analysis efforts conducted since the 1950s, researchers have established an understanding of the characteristic features of circulation in Puget Sound. The pattern ranges from the classic fjordal behavior in some basins, with shallow brackish outflow and compensating inflow immediately below, to the typical two-layer flow observed in many partially mixed estuaries with saline inflow at depth. An attempt at reproducing this behavior by fitting an analytical formulation to past data is presented, followed by the application of a three-dimensional circulation and transport numerical model. The analytical treatment helped identify key physical processes and parameters, but quickly reconfirmed that response is complex and would require site-specific parameterization to include effects of sills and interconnected basins. The numerical model of Puget Sound, developed using unstructured-grid finite volume method, allowed resolution of the sub-basin geometric features, including presence of major islands, and site-specific strong advective vertical mixing created by bathymetry and multiple sills. The model was calibrated using available recent short-term oceanographic time series data sets from different parts of the Puget Sound basin. The results are compared against (1) recent velocity and salinity data collected in Puget Sound from 2006 and (2) a composite data set from previously analyzed historical records, mostly from the 1970s. The results highlight the ability of the model to reproduce velocity and salinity profile characteristics, their variations among Puget Sound subbasins, and tidally averaged circulation. Sensitivity of residual circulation to variations in freshwater inflow and resulting salinity gradient in fjordal sub-basins of Puget Sound is examined.

  1. Quantifying Nonspecific TEM β-Lactamase (blaTEM) Genes in a Wastewater Stream▿

    PubMed Central

    Lachmayr, Karen L.; Kerkhof, Lee J.; DiRienzo, A. Gregory; Cavanaugh, Colleen M.; Ford, Timothy E.

    2009-01-01

    To control the antibiotic resistance epidemic, it is necessary to understand the distribution of genetic material encoding antibiotic resistance in the environment and how anthropogenic inputs, such as wastewater, affect this distribution. Approximately two-thirds of antibiotics administered to humans are β-lactams, for which the predominant bacterial resistance mechanism is hydrolysis by β-lactamases. Of the β-lactamases, the TEM family is of overriding significance with regard to diversity, prevalence, and distribution. This paper describes the design of DNA probes universal for all known TEM β-lactamase genes and the application of a quantitative PCR assay (also known as Taqman) to quantify these genes in environmental samples. The primer set was used to study whether sewage, both treated and untreated, contributes to the spread of these genes in receiving waters. It was found that while modern sewage treatment technologies reduce the concentrations of these antibiotic resistance genes, the ratio of blaTEM genes to 16S rRNA genes increases with treatment, suggesting that bacteria harboring blaTEM are more likely to survive the treatment process. Thus, β-lactamase genes are being introduced into the environment in significantly higher concentrations than occur naturally, creating reservoirs of increased resistance potential. PMID:18997031

  2. Analytical inversions in remote sensing of particle size distributions. IV - Comparison of Fymat and Box-McKellar solutions in the anomalous diffraction approximation

    NASA Technical Reports Server (NTRS)

    Fymat, A. L.; Smith, C. B.

    1979-01-01

    It is shown that the inverse analytical solutions, provided separately by Fymat and Box-McKellar, for reconstructing particle size distributions from remote spectral transmission measurements under the anomalous diffraction approximation can be derived using a cosine and a sine transform, respectively. Sufficient conditions of validity of the two formulas are established. Their comparison shows that the former solution is preferable to the latter in that it requires less a priori information (knowledge of the particle number density is not needed) and has wider applicability. For gamma-type distributions, and either a real or a complex refractive index, explicit expressions are provided for retrieving the distribution parameters; such expressions are, interestingly, proportional to the geometric area of the polydispersion.

  3. Sale of raw milk in northern Italy: food safety implications and comparison of different analytical methodologies for detection of foodborne pathogens.

    PubMed

    Giacometti, Federica; Serraino, Andrea; Finazzi, Guido; Daminelli, Paolo; Losio, Marina N; Arrigoni, Norma; Piva, Silvia; Florio, Daniela; Riu, Raffaela; Zanoni, Renato G

    2012-04-01

    The safety of raw milk sold in Northern Italy was investigated in relation to hygiene quality parameters and presence of Salmonella spp., Listeria monocytogenes, thermotolerant Campylobacter, and Verocytotoxin producing Escherichia coli O157:H7. The performance of different analytical methods used-official culture method (ISO), modified Bacteriological Analytical Manual cultural method (mBAM), and polymerase chain reaction (PCR)-was evaluated. The presence of Mycobacterium avium subsp. paratuberculosis (Map) was investigated only by PCR. All samples met regulations for alkaline phosphatase and inhibitory substance, while 18% and 44.8% of samples collected from vending machines had, respectively, somatic cell count (SCC) >300,000/mL and total bacterial count (TBC) >50,000 CFU/mL. The correlation between hygienic quality parameters in samples collected from bulk tank and vending machines showed a significant increase of TBC in vending machines meaning that raw milk was mishandled during distribution and sale. All pathogens investigated were detected in raw milk sold at vending machines; a total of five samples (5%) had at least one pathogen, of which two were detected by PCR and three by mBAM. None of the samples was positive by cultural ISO methods. Even if the comparison of analytical methods showed that none performs significantly better than the others, testing a higher volume of milk (25 versus 210 mL) affects significantly the detection rate of pathogens. Three samples (3%) were positive for Map, suggesting that raw milk is a significant source of Map exposure for consumers. The observed TBC increase and the detection of several pathogenic bacteria pose questions on the safety of raw milk; the use of ISO seems inefficient in detecting a low contamination level of pathogens in milk and consequently not appropriate as official method for testing. In order to ensure consumer's safety, a new approach for the raw milk chain is required.

  4. Analytical procedure for the simultaneous voltammetric determination of trace metals in food and environmental matrices. Critical comparison with atomic absorption spectroscopic measurements.

    PubMed

    Melucci, Dora; Torsi, Giancarlo; Locatelli, Clinio

    2007-01-01

    An analytical procedure fit for the simultaneous determination of copper (II), chromium(VI), thallium(I), lead(II), tin(II), antimony(III), and zinc(II) by square wave anodic stripping voltammetry (SWASV) in three interdependent environmental matrices involved in foods and food chain as meals, cereal plants and soils is described. The digestion of each matrix was carried out using a concentrated HCl-HNO3-H2SO4 (meals and cereal plants) and HCl-HNO3 (soils) acidic attack mixtures. 0.1 mol/L dibasic ammonium citrate pH 8.5 was employed as the supporting electrolyte. The voltammetric measurements were carried out using, as working electrode, a stationary hanging mercury drop electrode (HMDE) and a platinum electrode and an Ag/AgCl/KClsat electrode as auxiliary and reference electrodes, respectively. The analytical procedure was verified by the analyses of the standard reference materials: Wholemeal BCR-CRM 189, Tomato Leaves NIST-SRM 1573a and Montana Soil Moderately Elevated Traces NIST-SRM 2711. For all the elements in the certified matrix, the precision as repeatability, expressed as relative standard deviation (Sr %) was lower than 5%. The accuracy, expressed as percentage relative error (e %) was of the order of 3-7%, while the detection limits were in the range 0.015-0.103 microg/g. Once set up on the standard reference materials, the analytical procedure was transferred and applied to commercial meal samples, cereal plants and soils samples drawn in sites devoted to agricultural practice. A critical comparison with spectroscopic measurements is also discussed.

  5. Comparison of first and second generation analytical silica monoliths by pore-scale simulations of eddy dispersion in the bulk region.

    PubMed

    Hlushkou, Dzmitry; Hormann, Kristof; Höltzel, Alexandra; Khirevich, Siarhei; Seidel-Morgenstern, Andreas; Tallarek, Ulrich

    2013-08-16

    We present the first quantitative comparison of eddy dispersion in the bulk macropore (flow-through) space of 1st and 2nd generation analytical silica monoliths. Based on samples taken from the bulk region of Chromolith columns, segments of the bulk macropore space were physically reconstructed by confocal laser scanning microscopy to serve as models in pore-scale simulations of flow and dispersion. Our results cover details of the 3D velocity field, macroscopic Darcy permeability, transient and asymptotic dispersion behavior, and chromatographic band broadening, and thus correlate morphological, microscopic, and macroscopic properties. A complete set of parameters for the individual eddy dispersion contributions in the bulk was obtained from a Giddings analysis of the simulated plate height data. The identified short-range structural heterogeneities correspond to the average domain size of the respective monoliths. Our plate height curves show that structural improvements in the bulk morphology of 2nd generation monoliths play only a minor role for the observed improvement in overall column efficiency. The results also indicate a topological dissimilarity between 1st and 2nd generation analytical silica monoliths, which raises the question how the domain size of silica monoliths can be further decreased without compromising the structural homogeneity of the bed.

  6. Comparison of analytical and numerical approaches for CT-based aberration correction in transcranial passive acoustic imaging

    NASA Astrophysics Data System (ADS)

    Jones, Ryan M.; Hynynen, Kullervo

    2016-01-01

    Computed tomography (CT)-based aberration corrections are employed in transcranial ultrasound both for therapy and imaging. In this study, analytical and numerical approaches for calculating aberration corrections based on CT data were compared, with a particular focus on their application to transcranial passive imaging. Two models were investigated: a three-dimensional full-wave numerical model (Connor and Hynynen 2004 IEEE Trans. Biomed. Eng. 51 1693-706) based on the Westervelt equation, and an analytical method (Clement and Hynynen 2002 Ultrasound Med. Biol. 28 617-24) similar to that currently employed by commercial brain therapy systems. Trans-skull time delay corrections calculated from each model were applied to data acquired by a sparse hemispherical (30 cm diameter) receiver array (128 piezoceramic discs: 2.5 mm diameter, 612 kHz center frequency) passively listening through ex vivo human skullcaps (n  =  4) to emissions from a narrow-band, fixed source emitter (1 mm diameter, 516 kHz center frequency). Measurements were taken at various locations within the cranial cavity by moving the source around the field using a three-axis positioning system. Images generated through passive beamforming using CT-based skull corrections were compared with those obtained through an invasive source-based approach, as well as images formed without skull corrections, using the main lobe volume, positional shift, peak sidelobe ratio, and image signal-to-noise ratio as metrics for image quality. For each CT-based model, corrections achieved by allowing for heterogeneous skull acoustical parameters in simulation outperformed the corresponding case where homogeneous parameters were assumed. Of the CT-based methods investigated, the full-wave model provided the best imaging results at the cost of computational complexity. These results highlight the importance of accurately modeling trans-skull propagation when calculating CT-based aberration corrections

  7. Joint use of TEM and MRS methods in a complex geological setting

    NASA Astrophysics Data System (ADS)

    Legchenko, Anatoly; Ezersky, Michael; Camerlynck, Christian; Al-Zoubi, Abdallah; Chalikakis, Konstantinos

    2009-10-01

    Transient Electromagnetic (TEM), known also as Time Domain Electromagnetic (TDEM) and Magnetic Resonance Sounding (MRS) methods were applied jointly to investigate variations in lithology and groundwater salinity in the Nahal Hever South area (Dead Sea coast of Israel). The subsurface in this area is highly heterogeneous and composed of intercalated sand and clay layers over a salt formation, which is partly karstified. Groundwater is very saline, with a chloride concentration of 100-225 g/l. TEM is known as an efficient tool for investigating electrically conductive targets like saline water, but it is sensitive to both the salinity of groundwater and the porosity of rocks. MRS, however, is sensitive primarily to groundwater volume, but it also allows delineating of lithological variations in water-saturated formations. MRS is much less sensitive to variations in groundwater salinity in comparison with TEM. We show that MRS enables us to resolve the fundamental uncertainty in TEM interpretation caused by the equivalence between groundwater resistivity and lithology. Combining TEM and MRS, we found that the sandy Dead Sea aquifer filled with Dead Sea brine is characterized by a bulk resistivity of ρx > 0.4 Ωm, whereas zones with silt and clay in the subsurface are characterized by a bulk resistivity of ρx < 0.4 Ωm. These observations are confirmed by calibration of the TEM method performed near 18 boreholes.

  8. A-10/TF34 Turbine Engine Monitoring System (TEMS)

    NASA Technical Reports Server (NTRS)

    Christopher, R. G.

    1981-01-01

    The hardware and software development of the A-10/TF34 turbine engine monitoring system (TEMS) is described. The operation and interfaces of the A-10/TF34 TEMS hardware are discussed with particular emphasis on function, capabilities, and limitations. The TEMS data types are defined and the various data acquisition modes are explained. Potential data products are also discussed.

  9. Comparison of several analytical methods for the determination of tin in geochemical samples as a function of tin speciation

    USGS Publications Warehouse

    Kane, J.S.; Evans, J.R.; Jackson, J.C.

    1989-01-01

    Accurate and precise determinations of tin in geological materials are needed for fundamental studies of tin geochemistry, and for tin prospecting purposes. Achieving the required accuracy is difficult because of the different matrices in which Sn can occur (i.e. sulfides, silicates and cassiterite), and because of the variability of literature values for Sn concentrations in geochemical reference materials. We have evaluated three methods for the analysis of samples for Sn concentration: graphite furnace atomic absorption spectrometry (HGA-AAS) following iodide extraction, inductively coupled plasma atomic emission spectrometry (ICP-OES), and energy-dispersive X-ray fluorescence (EDXRF) spectrometry. Two of these methods (HGA-AAS and ICP-OES) required sample decomposition either by acid digestion or fusion, while the third (EDXRF) was performed directly on the powdered sample. Analytical details of all three methods, their potential errors, and the steps necessary to correct these errors were investigated. Results showed that similar accuracy was achieved from all methods for unmineralized samples, which contain no known Sn-bearing phase. For mineralized samples, which contain Sn-bearing minerals, either cassiterite or stannous sulfides, only EDXRF and fusion ICP-OES methods provided acceptable accuracy. This summary of our study provides information which helps to assure correct interpretation of data bases for underlying geochemical processes, regardless of method of data collection and its inherent limitations. ?? 1989.

  10. Isosteric heat of hydrogen adsorption on MOFs: comparison between adsorption calorimetry, sorption isosteric method, and analytical models

    NASA Astrophysics Data System (ADS)

    Kloutse, A. F.; Zacharia, R.; Cossement, D.; Chahine, R.; Balderas-Xicohténcatl, R.; Oh, H.; Streppel, B.; Schlichtenmayer, M.; Hirscher, M.

    2015-12-01

    Isosteric heat of adsorption is an important parameter required to describe the thermal performance of adsorptive storage systems. It is most frequently calculated from adsorption isotherms measured over wide ranges of pressure and temperature, using the so-called adsorption isosteric method. Direct quantitative estimation of isosteric heats on the other hand is possible using the coupled calorimetric-volumetric method, which involves simultaneous measurement of heat and adsorption. In this work, we compare the isosteric heats of hydrogen adsorption on microporous materials measured by both methods. Furthermore, the experimental data are compared with the isosteric heats obtained using the modified Dubinin-Astakhov, Tóth, and Unilan adsorption analytical models to establish the reliability and limitations of simpler methods and assumptions. To this end, we measure the hydrogen isosteric heats on five prototypical metal-organic frameworks: MOF-5, Cu-BTC, Fe-BTC, MIL-53, and MOF-177 using both experimental methods. For all MOFs, we find a very good agreement between the isosteric heats measured using the calorimetric and isosteric methods throughout the range of loading studied. Models' prediction on the other hand deviates from both experiments depending on the MOF studied and the range of loading. Under low-loadings of less than 5 mol kg-1, the isosteric heat of hydrogen adsorption decreases in the order Cu-BTC > MIL-53 > MOF-5 > Fe-BTC > MOF-177. The order of isosteric heats is coherent with the strength of hydrogen interaction revealed from previous thermal desorption spectroscopy measurements.

  11. Production of neutrons in laminated barriers of radiotherapy rooms: comparison between the analytical methodology and Monte Carlo simulations.

    PubMed

    da Silva Rezende, Gabriel Fonseca; da Rosa, Luiz Antonio Ribeiro; Facure, Alessandro

    2014-11-01

    The necessity to build or adapt radiotherapy rooms in reduced areas leads to the search for unconventional solutions for shielding projects. In most cases, adding metals to the primary barriers is the best alternative to shield rooms properly. However, when photons with energies equal or higher than 10 MV interact with high atomic number nuclei, neutrons are ejected and may result in a radioprotection problem for both outside and inside the room. Currently, the most widely used mathematical model to estimate the neutron dose equivalents, beyond the barriers composed by concrete and metal, is applicable only in very specific conditions. Moreover, a validation work of this model had not yet been performed. In this work, the Monte Carlo code MCNPX was used to check the validity of the aforementioned mathematical model for cases of primary barriers containing steel or lead sheets, considering the existence of linear accelerators of 15 or 18 MV. The results of the study showed that over 80% of the values obtained by computational simulations revealed deviations above a factor of 2, when compared to the analytical formula. This led to the conclusion that the McGinley method cannot be considered an adequate mathematical model to describe the mentioned physical phenomenon. PACS numbers: 87.56.bd, 02.70.Uu.

  12. Production of neutrons in laminated barriers of radiotherapy rooms: comparison between the analytical methodology and Monte Carlo simulations.

    PubMed

    Rezende, Gabriel Fonseca da Silva; Da Rosa, Luiz Antonio Ribeiro; Facure, Alessandro

    2014-11-08

    The necessity to build or adapt radiotherapy rooms in reduced areas leads to the search for unconventional solutions for shielding projects. In most cases, adding metals to the primary barriers is the best alternative to shield rooms properly. However, when photons with energies equal or higher than 10 MV interact with high atomic number nuclei, neutrons are ejected and may result in a radioprotec- tion problem for both outside and inside the room. Currently, the most widely used mathematical model to estimate the neutron dose equivalents, beyond the barriers composed by concrete and metal, is applicable only in very specific conditions. Moreover, a validation work of this model had not yet been performed. In this work, the Monte Carlo code MCNPX was used to check the validity of the aforementioned mathematical model for cases of primary barriers containing steel or lead sheets, considering the existence of linear accelerators of 15 or 18 MV. The results of the study showed that over 80% of the values obtained by computational simulations revealed deviations above a factor of 2, when compared to the analytical formula. This led to the conclusion that the McGinley method cannot be considered an adequate mathematical model to describe the mentioned physical phenomenon. 

  13. Comparison of Three Analytical Methods for the Quantitation of Mercury in Environmental Samples from the Volta Lake, Ghana.

    PubMed

    Kwaansa-Ansah, Edward Ebow; Adimado, Anthony Apeke; Nriagu, Jerome Okon; Basu, Niladri

    2016-11-01

    Three analytical methods using automatic mercury analyzer (AMA), direct mercury analyzer (DMA) and inductively coupled plasma-mass spectrometry (ICP-MS) were applied to determine mercury in fish and sediment samples from the Volta Lake in Ghana with the aim of comparing their accuracy, precision, and limit of quantifications. There was statistically no significant difference (p < 0.05) between the concentrations recorded by the methods. This indicates their suitability for the accurate determination of mercury. Limit of quantification was found to be in the order; ICP-MS (0.053 ng/g) < DMA (0.527 ng/g) < AMA (2.193 ng/g). Though each of the three methods has a suitable ability in determining accurately the concentrations of mercury in fish and sediment, for the determination of very low concentrations of mercury ICP-MS should be preferred considering the order of the detection limit which follows the trend ICP-MS (0.016 ng/g) < DMA (0.158 ng/g) < AMA (0.509 ng/g).

  14. Interaction of High Frequency Electromagnetic Waves with Vortex Density Structures: Comparison of Analytical and LSP Simulation Results

    NASA Astrophysics Data System (ADS)

    Sotnikov, V.; Kim, T.; Lundberg, J.; Paraschiv, I.; Mehlhorn, T. A.

    2014-10-01

    Interchange or flute type density irregularities in magnetized plasma are associated with Rayleigh-Taylor type instability. In particular, we are interested in the generation of low frequency plasma density irregularities in the form of flute type vortex density structures and interaction of high frequency electromagnetic waves used for surveillance and communication with such structures. These types of density irregularities play an important role in refraction and scattering of high frequency electromagnetic signals propagating in the earth ionosphere, in high energy density physics (HEDP), and in many other applications. We will present PIC simulation results of EM scattering on vortex type density structures using the LSP code and compare them with analytical results. Two cases will be analyzed. In the first case electromagnetic wave scattering will take place in the ionospheric plasma. In the second case laser probing in a high-beta Z-pinch plasma will be presented. This work was supported by the Air Force Research laboratory, the Air Force Office of Scientific Research, the Naval Research Laboratory and NNSA/DOE Grant No. DE-FC52-06NA27616 at the University of Nevada at Reno.

  15. State-dependent anisotrophy--Comparison of quasi-analytical solutions with stochastic results for steady gravity drainage

    USGS Publications Warehouse

    Green, Timothy R.; Freyberg, David L.

    1995-01-01

    Anisotropy in large-scale unsaturated hydraulic conductivity of layered soils changes with the moisture state. Here, state-dependent anisotropy is computed under conditions of large-scale gravity drainage. Soils represented by Gardner's exponential function are perfectly stratified, periodic, and inclined. Analytical integration of Darcy’s law across each layer results in a system of nonlinear equations that is solved iteratively for capillary suction at layer interfaces and for the Darcy flux normal to layering. Computed fluxes and suction profiles are used to determine both upscaled hydraulic conductivity in the principal directions and the corresponding “state-dependent” anisotropy ratio as functions of the mean suction. Three groups of layered soils are analyzed and compared with independent predictions from the stochastic results of Yeh et al. (1985b). The small-perturbation approach predicts appropriate behaviors for anisotropy under nonarid conditions. However, the stochastic results are limited to moderate values of mean suction; this limitation is linked to a Taylor series approximation in terms of a group of statistical and geometric parameters. Two alternative forms of the Taylor series provide upper and lower bounds for the state-dependent anisotropy of relatively dry soils.

  16. Use of the Relaxometry Technique for Quantification of Paramagnetic Ions in Aqueous Solutions and a Comparison with Other Analytical Methods

    PubMed Central

    Burato, Juliana Soares da Silva; Silva Lobo, Carlos Manuel; Colnago, Luiz Alberto

    2016-01-01

    We have demonstrated that the relaxometry technique is very efficient to quantify paramagnetic ions during in situ electrolysis measurements. Therefore, the goal of this work was to validate the relaxometry technique in the determination of the concentration of the ions contained in electrolytic solutions, Cu2+, Ni2+, Cr3+, and Mn2+, and compare it with other analytical methods. Two different NMR spectrometers were used: a commercial spectrometer with a homogeneous magnetic field and a home-built unilateral sensor with an inhomogeneous magnetic field. Without pretreatment, manganese ions do not have absorption bands in the UV-Visible region, but it is possible to quantify them using relaxometry (the limit of quantification is close to 10−5 mol L−1). Therefore, since the technique does not require chemical indicators and is a cheap and robust method, it can be used as a replacement for some conventional quantification techniques. The relaxometry technique could be applied to evaluate the corrosion of metallic surfaces. PMID:27293437

  17. Comparison of experimental and analytical temperatures achieved by DT-18 and PC-1 shipping containers during hypothetical thermal accident tests

    SciTech Connect

    Anderson, J.C.

    1992-03-01

    Temperatures were monitored at various locations on DT-18 and PC-1 shipping packages during furnace tests at the Y-12 Plant in Oak Ridge, Tennessee. The furnace tests are intended to simulate hypothetical thermal accident conditions specified in Title 10 CFR, Pt. 71.73 (c)(3). Maximum temperatures of the outer containers ranged from 750 to 965{degrees}C while typical maximum temperatures recorded on the inner containers were 60 to 77{degrees}C. One exceptionally high temperature of 196{degrees}C occurred on the PC-1 inner container. Heating 7.1 models of both the DT-18 and PC-1 packages were developed. Models with and without heat generation in the inner containers were developed for each shipping package. The models with heat generation are intended to simulate condensation and convection of hot vapors generated during the heating of the Celotex{trademark} insulating material used in the packages. In general, the analytical models calculate temperatures for the outer containers which agree well with the test data. The HEATING models with and without heat generation bound the inner container test data. These findings are significant in that they lead to the conclusion that heat is transferred to the inner containers through a mechanism other than conduction alone. The high temperature of 196{degrees}C recorded at the PC-1 inner container is within 4{degrees}C of the maximum temperature calculated by the PC-1 HEATING model with heat generation.

  18. Analytic parallel-polarized light imaging technique using various light-emitting diodes: a comparison with skin conductance values.

    PubMed

    Kim, D H; Choi, J E; Ryu, H J; Seo, S H; Kye, Y C; Ahn, H H

    2015-05-01

    The quantitative difference of the light reflected from a skin surface can be analyzed using parallel-polarized light (PPL) photography when combined with an analytic technique similar to colorimetric photography. To improve the PPL photography technique as an assessment tool for the evaluation of skin condition using light-emitting diodes (LED) of different colors. Parallel-polarized light images were taken using white and green LED illuminators. The acquired images were transformed to CIELAB coordinates. An in-house skin conductance meter was constructed to assess skin hydration level. A dermatologist evaluated the clinical grading of dryness and glossiness. These clinical severities were also compared statistically with the CIELAB values. As with the green illuminator, the correlation analysis of whole sites showed that the L* value positively correlated with age (r = 0.18677, P < 0.05), and that the a* value has negative and positive relationships with age (r = -0.20528, P < 0.05) and glossiness (r = 0.20885, P < 0.05) respectively. The correlations between CIELAB values and multiple characteristics of skin were more significant when green LED was applied than when white light was applied. In addition, coherent relationships between the grade of dryness and skin conductance values showed that visual assessment could be appropriate for the study as with objective measurement. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. Acute, intermediate intensity exercise, and speed and accuracy in working memory tasks: a meta-analytical comparison of effects.

    PubMed

    McMorris, Terry; Sproule, John; Turner, Anthony; Hale, Beverley J

    2011-03-01

    The purpose of this study was to compare, using meta-analytic techniques, the effect of acute, intermediate intensity exercise on the speed and accuracy of performance of working memory tasks. It was hypothesized that acute, intermediate intensity exercise would have a significant beneficial effect on response time and that effect sizes for response time and accuracy data would differ significantly. Random-effects meta-analysis showed a significant, beneficial effect size for response time, g=-1.41 (p<0.001) but a significant detrimental effect size, g=0.40 (p<0.01), for accuracy. There was a significant difference between effect sizes (Z(diff)=3.85, p<0.001). It was concluded that acute, intermediate intensity exercise has a strong beneficial effect on speed of response in working memory tasks but a low to moderate, detrimental one on accuracy. There was no support for a speed-accuracy trade-off. It was argued that exercise-induced increases in brain concentrations of catecholamines result in faster processing but increases in neural noise may negatively affect accuracy.

  20. Comparison of analytical methods for percent phosphorous determination in electroless nickel plate. [UCC-ND alkalimetric method; UCC-ND Inductively Coupled Plasma (ICP) method; ASTM-E39 gravimetric method; development colorimetric method; independent colorimetric method

    SciTech Connect

    Owens, W.W.; Sullivan, H.H.

    1982-01-01

    Electroless nicke-plate characteristics are substantially influenced by percent phosphorous concentrations. Available ASTM analytical methods are designed for phosphorous concentrations of less than one percent compared to the 4.0 to 20.0% concentrations common in electroless nickel plate. A variety of analytical adaptations are applied through the industry resulting in poor data continuity. This paper presents a statistical comparison of five analytical methods and recommends accurate and precise procedures for use in percent phosphorous determinations in electroless nickel plate. 2 figures, 1 table.

  1. Motorized manipulator for positioning a TEM specimen

    DOEpatents

    Schmid, Andreas Karl; Andresen, Nord

    2010-12-14

    The invention relates to a motorized manipulator for positioning a TEM specimen holder with sub-micron resolution parallel to a y-z plane and rotating the specimen holder in the y-z plane, the manipulator comprising a base (2), and attachment means (30) for attaching the specimen holder to the manipulator, characterized in that the manipulator further comprises at least three nano-actuators (3.sup.a, 3.sup.b, 3.sup.c) mounted on the base, each nano-actuator showing a tip (4.sup.a, 4.sup.b, 4.sup.c), the at least three tips defining the y-z plane, each tip capable of moving with respect to the base in the y-z plane; a platform (5) in contact with the tips of the nano-actuators; and clamping means (6) for pressing the platform against the tips of the nano-actuators; as a result of which the nano-actuators can rotate the platform with respect to the base in the y-z plane and translate the platform parallel to the y-z plane.

  2. SIMS and TEM Analysis of Niobium Bicrystals

    SciTech Connect

    Maheshwari, P; Griffis, D P; Stevie, F A; Zhou, C; Ciovati, G; Myneni, R; Spradlin, J K; Rigsbee, M

    2011-07-01

    The behaviour of interstitial impurities(C,O,N,H) on the Nb surface with respect to grain boundaries may affect cavity performance. Large grain Nb makes possible the selection of bicrystal samples with a well defined grain boundary. In this work, Dynamic SIMS was used to analyze two Nb bicrystal samples, one of them heat treated and the other non heat treated (control). H levels were found to be higher for the non heat treated sample and a difference in the H intensity and sputtering rate was also observed across the grain boundary for both the samples. TEM results showed that the bicrystal interface showed no discontinuity and the oxide layer was uniform across the grain boundary for both the samples. TOF-SIMS imaging was also performed to analyze the distribution of the impurities across the grain boundary in both the samples. C was observed to be segregated along the grain boundary for the control sample, while H and O showed a difference in signal intensity across the grain boundary. Crystal orientation appears to have an important role in the observed sputtering rate and impurity ion signal differences both across the grain boundary and between samples

  3. Quantification of crystalline cellulose in lignocellulosic biomass using sum frequency generation (SFG) vibration spectroscopy and comparison with other analytical methods.

    PubMed

    Barnette, Anna L; Lee, Christopher; Bradley, Laura C; Schreiner, Edward P; Park, Yong Bum; Shin, Heenae; Cosgrove, Daniel J; Park, Sunkyu; Kim, Seong H

    2012-07-01

    The non-centrosymmetry requirement of sum frequency generation (SFG) vibration spectroscopy allows the detection and quantification of crystalline cellulose in lignocellulose biomass without spectral interferences from hemicelluloses and lignin. This paper shows a correlation between the amount of crystalline cellulose in biomass and the SFG signal intensity. Model biomass samples were prepared by mixing commercially available cellulose, xylan, and lignin to defined concentrations. The SFG signal intensity was found sensitive to a wide range of crystallinity, but varied non-linearly with the mass fraction of cellulose in the samples. This might be due to the matrix effects such as light scattering and absorption by xylan and lignin, as well as the non-linear density dependence of the SFG process itself. Comparison with other techniques such as XRD, FT-Raman, FT-IR and NMR demonstrate that SFG can be a complementary and sensitive tool to assess crystalline cellulose in biomass.

  4. TEM Study of SAFARI-2000 Aerosols

    NASA Technical Reports Server (NTRS)

    Buseck, Peter R.

    2004-01-01

    The aim of our research was to obtain data on the chemical and physical properties of individual aerosol particles from biomass smoke plume s in southern Africa and from air masses in the region that are affec ted by the smoke. We used analytical transmission electron microscopy (ATEM), including energy-dispersive X-ray spectrometry (EDS) and ele ctron energy-loss spectroscopy (EELS), and field-emission electron microscopy (FESEM) to study aerosol particles from several smoke and haz e samples and from a set of cloud samples.

  5. Comparison in the analytical performance between krypton and argon glow discharge plasmas as the excitation source for atomic emission spectrometry.

    PubMed

    Wagatsuma, Kazuaki

    2009-04-01

    The emission characteristics of ionic lines of nickel, cobalt, and vanadium were investigated when argon or krypton was employed as the plasma gas in glow discharge optical emission spectrometry. A dc Grimm-style lamp was employed as the excitation source. Detection limits of the ionic lines in each iron-matrix alloy sample were compared between the krypton and the argon plasmas. Particular intense ionic lines were observed in the emission spectra as a function of the discharge gas (krypton or argon), such as the Co II 258.033 nm for krypton and the Co II 231.707 nm for argon. The explanation for this is that collisions with the plasma gases dominantly populate particular excited levels of cobalt ion, which can receive the internal energy from each gas ion selectively, for example, the 3d(7)4p (3)G(5) (6.0201 eV) for krypton and the 3d(7)4p (3)G(4) (8.0779 eV) for argon. In the determination of nickel as well as cobalt in iron-matrix samples, more sensitive ionic lines could be found in the krypton plasma rather than the argon plasma. Detection limits in the krypton plasma were 0.0039 mass% Ni for the Ni II 230.299-nm line and 0.002 mass% Co for the Co II 258.033-nm line. However, in the determination of vanadium, the argon plasma had better analytical performance, giving a detection limit of 0.0023 mass% V for the V II 309.310-nm line.

  6. HELIOSPHERIC PROPAGATION OF CORONAL MASS EJECTIONS: COMPARISON OF NUMERICAL WSA-ENLIL+CONE MODEL AND ANALYTICAL DRAG-BASED MODEL

    SciTech Connect

    Vršnak, B.; Žic, T.; Dumbović, M.; Temmer, M.; Möstl, C.; Veronig, A. M.; Taktakishvili, A.; Mays, M. L.; Odstrčil, D. E-mail: tzic@geof.hr E-mail: manuela.temmer@uni-graz.at E-mail: astrid.veronig@uni-graz.at E-mail: m.leila.mays@nasa.gov

    2014-08-01

    Real-time forecasting of the arrival of coronal mass ejections (CMEs) at Earth, based on remote solar observations, is one of the central issues of space-weather research. In this paper, we compare arrival-time predictions calculated applying the numerical ''WSA-ENLIL+Cone model'' and the analytical ''drag-based model'' (DBM). Both models use coronagraphic observations of CMEs as input data, thus providing an early space-weather forecast two to four days before the arrival of the disturbance at the Earth, depending on the CME speed. It is shown that both methods give very similar results if the drag parameter Γ = 0.1 is used in DBM in combination with a background solar-wind speed of w = 400 km s{sup –1}. For this combination, the mean value of the difference between arrival times calculated by ENLIL and DBM is Δ-bar =0.09±9.0 hr with an average of the absolute-value differences of |Δ|-bar =7.1 hr. Comparing the observed arrivals (O) with the calculated ones (C) for ENLIL gives O – C = –0.3 ± 16.9 hr and, analogously, O – C = +1.1 ± 19.1 hr for DBM. Applying Γ = 0.2 with w = 450 km s{sup –1} in DBM, one finds O – C = –1.7 ± 18.3 hr, with an average of the absolute-value differences of 14.8 hr, which is similar to that for ENLIL, 14.1 hr. Finally, we demonstrate that the prediction accuracy significantly degrades with increasing solar activity.

  7. Comparison of chemistry analytes between 2 portable, commercially available analyzers and a conventional laboratory analyzer in reptiles.

    PubMed

    McCain, Stephanie L; Flatland, Bente; Schumacher, Juergen P; Clarke Iii, Elsburgh O; Fry, Michael M

    2010-12-01

    Advantages of handheld and small bench-top biochemical analyzers include requirements for smaller sample volume and practicality for use in the field or in practices, but little has been published on the performance of these instruments compared with standard reference methods in analysis of reptilian blood. The aim of this study was to compare reptilian blood biochemical values obtained using the Abaxis VetScan Classic bench-top analyzer and a Heska i-STAT handheld analyzer with values obtained using a Roche Hitachi 911 chemical analyzer. Reptiles, including 14 bearded dragons (Pogona vitticeps), 4 blue-tongued skinks (Tiliqua gigas), 8 Burmese star tortoises (Geochelone platynota), 10 Indian star tortoises (Geochelone elegans), 5 red-tailed boas (Boa constrictor), and 5 Northern pine snakes (Pituophis melanoleucus melanoleucus), were manually restrained, and a single blood sample was obtained and divided for analysis. Results for concentrations of albumin, bile acids, calcium, glucose, phosphates, potassium, sodium, total protein, and uric acid and activities of aspartate aminotransferase and creatine kinase obtained from the VetScan Classic and Hitachi 911 were compared. Results for concentrations of chloride, glucose, potassium, and sodium obtained from the i-STAT and Hitachi 911 were compared. Compared with results from the Hitachi 911, those from the VetScan Classic and i-STAT had variable correlations, and constant or proportional bias was found for many analytes. Bile acid data could not be evaluated because results for 44 of 45 samples fell below the lower linearity limit of the VetScan Classic. Although the 2 portable instruments might provide measurements with clinical utility, there were significant differences compared with the reference analyzer, and development of analyzer-specific reference intervals is recommended. ©2010 American Society for Veterinary Clinical Pathology.

  8. Comparison of Analytic Hierarchy Process, Catastrophe and Entropy techniques for evaluating groundwater prospect of hard-rock aquifer systems

    NASA Astrophysics Data System (ADS)

    Jenifer, M. Annie; Jha, Madan K.

    2017-05-01

    Groundwater is a treasured underground resource, which plays a central role in sustainable water management. However, it being hidden and dynamic in nature, its sustainable development and management calls for precise quantification of this precious resource at an appropriate scale. This study demonstrates the efficacy of three GIS-based multi-criteria decision analysis (MCDA) techniques, viz., Analytic Hierarchy Process (AHP), Catastrophe and Entropy in evaluating groundwater potential through a case study in hard-rock aquifer systems. Using satellite imagery and relevant field data, eight thematic layers (rainfall, land slope, drainage density, soil, lineament density, geology, proximity to surface water bodies and elevation) of the factors having significant influence on groundwater occurrence were prepared. These thematic layers and their features were assigned suitable weights based on the conceptual frameworks of AHP, Catastrophe and Entropy techniques and then they were integrated in the GIS environment to generate an integrated raster layer depicting groundwater potential index of the study area. The three groundwater prospect maps thus yielded by these MCDA techniques were verified using a novel approach (concept of 'Dynamic Groundwater Potential'). The validation results revealed that the groundwater potential predicted by the AHP technique has a pronounced accuracy of 87% compared to the Catastrophe (46% accuracy) and Entropy techniques (51% accuracy). It is concluded that the AHP technique is the most reliable for the assessment of groundwater resources followed by the Entropy method. The developed groundwater potential maps can serve as a scientific guideline for the cost-effective siting of wells and the effective planning of groundwater development at a catchment or basin scale.

  9. Comparison Of The Global Analytic Models Of The Main Geomagnetic Field With The Stratospheric Balloon Magnetic Data 335

    NASA Astrophysics Data System (ADS)

    Tsvetkov, Yu.; Filippov, S.; Frunze, A.

    2013-12-01

    Three global analytical models of a main geomagnetic field constructed by satellite data are used: model IGRF, Daily Mean Spherical Harmonic Models (DMSHM), and model EMM/2010, and also scalar data of geomagnetic field and its gradients, received in stratospheric balloon gradient magnetic surveys at altitudes of ~30 km. At these altitudes the regional magnetic field is formed from all sources of the Earth's crust. It enables to receive along lengthy routes of surveys the fullest data on regional and longwave-lenght magnetic anomalies. Model DMSHM is used at extracting of magnetic anomalies for elimination of a secular variation up to significant value 0,2 nT. The model can be constructed within the limits of ± 1 months from the moment stratospheric balloon surveys with beneficial day terms with magnetic activity up to Kp <20, that leads to an error of representation of main MFE equal ±5 нТл. It is possible at presence acting for the period of stratospheric balloon magnetic survey of the satellite, for example, Swarm. On stratospheric balloon data it is shown, that model EMM/2010 unsatisfactorily displays MFE at altitude of 30 km. Hence, the qualitative model of the constant (main and anomaly) magnetic field cannot be constructed only with use of satellite and ground data. The improved model constant MFE, constructed according to satellite and stratospheric balloon magnetic surveys, developed up to a degree and the order m=n=720, will have a reliable data about regional crust magnetic field, hence, and about deep magnetic structure of the Earth's crust. The use gradient magnetic surveys aboard stratospheric balloons allows to find the places alternating approximately through 3000 km in which there are no magnetic anomalies. In these places probably to supervise satellite magnetic models for a range of altitude of 20-40 km, timed to stratospheric balloon magnetic surveys.

  10. Introducing process analytical technology (PAT) in filamentous cultivation process development: comparison of advanced online sensors for biomass measurement.

    PubMed

    Rønnest, Nanna Petersen; Stocks, Stuart M; Eliasson Lantz, Anna; Gernaey, Krist V

    2011-10-01

    The recent process analytical technology (PAT) initiative has put an increased focus on online sensors to generate process-relevant information in real time. Specifically for fermentation, however, introduction of online sensors is often far from straightforward, and online measurement of biomass is one of the best examples. The purpose of this study was therefore to compare the performance of various online biomass sensors, and secondly to demonstrate their use in early development of a filamentous cultivation process. Eight Streptomyces coelicolor fed-batch cultivations were run as part of process development in which the pH, the feeding strategy, and the medium composition were varied. The cultivations were monitored in situ using multi-wavelength fluorescence (MWF) spectroscopy, scanning dielectric (DE) spectroscopy, and turbidity measurements. In addition, we logged all of the classical cultivation data, such as the carbon dioxide evolution rate (CER) and the concentration of dissolved oxygen. Prediction models for the biomass concentrations were estimated on the basis of the individual sensors and on combinations of the sensors. The results showed that the more advanced sensors based on MWF and scanning DE spectroscopy did not offer any advantages over the simpler sensors based on dual frequency DE spectroscopy, turbidity, and CER measurements for prediction of biomass concentration. By combining CER, DE spectroscopy, and turbidity measurements, the prediction error was reduced to 1.5 g/l, corresponding to 6% of the covered biomass range. Moreover, by using multiple sensors it was possible to check the quality of the individual predictions and switch between the sensors in real time.

  11. TEM10 homodyne detection as an optimal small-displacement and tilt-measurement scheme

    NASA Astrophysics Data System (ADS)

    Delaubert, V.; Treps, N.; Lassen, M.; Harb, C. C.; Fabre, C.; Lam, P. K.; Bachor, H.-A.

    2006-11-01

    We present a detailed description of small displacement and tilt measurements of a Gaussian beam using split detectors and TEM10 homodyne detectors. Theoretical analysis and an experimental demonstration of measurements of these two conjugate variables are given. A comparison between the experimental efficiency of each scheme proves that the standard split detection is only 64% efficient relative to the TEM10 homodyne detection, which is optimal for beam displacement and tilt. We also demonstrate experimentally that squeezed light in the appropriate spatial modes allows measurements beyond the quantum noise limit for both types of detectors. Finally, we explain how to choose the detection scheme best adapted to a given application.

  12. Rapid approximate inversion of airborne TEM

    NASA Astrophysics Data System (ADS)

    Fullagar, Peter K.; Pears, Glenn A.; Reid, James E.; Schaa, Ralf

    2015-11-01

    Rapid interpretation of large airborne transient electromagnetic (ATEM) datasets is highly desirable for timely decision-making in exploration. Full solution 3D inversion of entire airborne electromagnetic (AEM) surveys is often still not feasible on current day PCs. Therefore, two algorithms to perform rapid approximate 3D interpretation of AEM have been developed. The loss of rigour may be of little consequence if the objective of the AEM survey is regional reconnaissance. Data coverage is often quasi-2D rather than truly 3D in such cases, belying the need for `exact' 3D inversion. Incorporation of geological constraints reduces the non-uniqueness of 3D AEM inversion. Integrated interpretation can be achieved most readily when inversion is applied to a geological model, attributed with lithology as well as conductivity. Geological models also offer several practical advantages over pure property models during inversion. In particular, they permit adjustment of geological boundaries. In addition, optimal conductivities can be determined for homogeneous units. Both algorithms described here can operate on geological models; however, they can also perform `unconstrained' inversion if the geological context is unknown. VPem1D performs 1D inversion at each ATEM data location above a 3D model. Interpretation of cover thickness is a natural application; this is illustrated via application to Spectrem data from central Australia. VPem3D performs 3D inversion on time-integrated (resistive limit) data. Conversion to resistive limits delivers a massive increase in speed since the TEM inverse problem reduces to a quasi-magnetic problem. The time evolution of the decay is lost during the conversion, but the information can be largely recovered by constructing a starting model from conductivity depth images (CDIs) or 1D inversions combined with geological constraints if available. The efficacy of the approach is demonstrated on Spectrem data from Brazil. Both separately and in

  13. A comparison of sampling and analytical methods for assessing occupational exposure to diesel exhaust in a railroad work environment

    SciTech Connect

    Verma, D.K.; Shaw, L.; Julian, J.; Smolynec, K.; Wood, C.; Shaw, D.

    1999-10-01

    Methods of assessing occupational exposure to diesel exhaust were evaluated in a railroad work environment. The American Conference of Governmental Industrial Hygienists (ACGIH{reg_sign})-recommended elemental carbon and respirable combustible dust methods of sampling and analysis for assessing diesel exhaust were included in the study. A total of 215 personal and area samples were collected using both size-selective and non-size-selective samplers. The results demonstrate that the elemental carbon method is suitable for the railroad environment and the respirable combustible dust method is not. All elemental carbon concentrations measured were below the proposed ACG1H Threshold Limit Value (TLV{reg_sign}) of 0.15 mg/m{sup 3}. The concentrations of oxides of nitrogen (nitric oxide and nitrogen dioxide) were also found to be below their respective TLVs. There is no correlation between elemental carbon or respirable combustible dust and the oxides of nitrogen. The elemental carbon as fraction of total carbon is about 13%, except for onboard locomotives where it is about 24%. Comparison of elemental carbon and respirable combustible dust measurements showed consistent relationships for most sampling locations with respirable combustible dust concentrations 12 to 53 times higher than the elemental carbon levels.

  14. A smog chamber comparison of a microfluidic derivatisation measurement of gas-phase glyoxal and methylglyoxal with other analytical techniques

    NASA Astrophysics Data System (ADS)

    Pang, X.; Lewis, A. C.; Rickard, A. R.; Baeza-Romero, M. T.; Adams, T. J.; Ball, S. M.; Daniels, M. J. S.; Goodall, I. C. A.; Monks, P. S.; Peppe, S.; Ródenas García, M.; Sánchez, P.; Muñoz, A.

    2014-02-01

    A microfluidic lab-on-a-chip derivatisation technique has been developed to measure part per billion (ppbV) mixing ratios of gaseous glyoxal (GLY) and methylglyoxal (MGLY), and the method is compared with other techniques in a smog chamber experiment. The method uses o-(2, 3, 4, 5, 6-pentafluorobenzyl) hydroxylamine (PFBHA) as a derivatisation reagent and a microfabricated planar glass micro-reactor comprising an inlet, gas and fluid splitting and combining channels, mixing junctions, and a heated capillary reaction microchannel. The enhanced phase contact area-to-volume ratio and the high heat transfer rate in the micro-reactor resulted in a fast and highly efficient derivatisation reaction, generating an effluent stream ready for direct introduction to a gas chromatograph-mass spectrometer (GC-MS). A linear response for GLY was observed over a calibration range 0.7 to 400 ppbV, and for MGLY of 1.2 to 300 ppbV, when derivatised under optimal reaction conditions. The analytical performance shows good accuracy (6.6% for GLY and 7.5% for MGLY), suitable precision (<12.0%) with method detection limits (MDLs) of 75 pptV for GLY and 185 pptV for MGLY, with a time resolution of 30 min. These MDLs are below or close to typical concentrations of these compounds observed in ambient air. The feasibility of the technique was assessed by applying the methodology to quantify α-dicarbonyls formed during the photo-oxidation of isoprene in the EUPHORE chamber. Good correlations were found between microfluidic measurements and Fourier Transform InfraRed spectroscopy (FTIR) with a correlation coefficient (r2) of 0.84, Broadband Cavity Enhanced Absorption Spectroscopy (BBCEAS) (r2 = 0.75), solid phase micro extraction (SPME) (r2 = 0.89), and a photochemical chamber box modelling calculation (r2 = 0.79) for GLY measurements. For MGLY measurements, the microfluidic technique showed good agreement with BBCEAS (r2 = 0.87), SPME (r2 = 0.76), and the modeling simulation (r2 = 0.83), FTIR

  15. A smog chamber comparison of a microfluidic derivatisation measurement of gas-phase glyoxal and methylglyoxal with other analytical techniques

    NASA Astrophysics Data System (ADS)

    Pang, xiaobing; Lewis, Alastair; Rickard, Andrew R.; Baeza-Romero, Maria Teresa; Adams, Thomas J.; Ball, Stephen M.; Goodall, Iain C. A.; Monks, Paul S.; Peppe, Salvatore; Ródenas García, Milagros; Sánchez, Pilar; Muñoz, Amalia

    2014-05-01

    A microfluidic lab-on-a-chip derivatisation technique has been developed to measure part per billion (ppbV) mixing ratios of gaseous glyoxal (GLY) and methylglyoxal (MGLY), and the method is compared with other techniques in a smog chamber experiment. The method uses o-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine (PFBHA) as a derivatisation reagent and a microfabricated planar glass micro-reactor comprising an inlet, gas and fluid splitting and combining channels, mixing junctions, and a heated capillary reaction microchannel. The enhanced phase contact area-to-volume ratio and the high heat transfer rate in the micro-reactor result in a fast and highly efficient derivatisation reaction, generating an effluent stream ready for direct introduction to a gas chromatograph-mass spectrometer (GC-MS). A linear response for GLY was observed over a calibration range 0.7 to 400 ppbV, and for MGLY of 1.2 to 300 ppbV, when derivatised under optimal reaction conditions. The analytical performance shows good accuracy (6.6 % for GLY and 7.5 % for MGLY), suitable precision (< 12.0 %) and method detection limits (MDLs) (75 pptV for GLY and 185 pptV for MGLY) with a time resolution of 30 minutes. These MDLs are below or close to typical concentrations of these compounds observed in ambient air. The microfluidic derivatisation technique would be appropriate for ambient α-dicarbonyl measurements in a range of field environments based on its performance in a large-scale outdoor atmospheric simulation chamber (EUPHORE). The feasibility of the technique was assessed by applying the methodology to quantify of α-dicarbonyls formed during the photo-oxidation of isoprene in the EUPHORE chamber. Good correlations were found between microfluidic measurements and Fourier Transform InfraRed spectroscopy (FTIR) with the correlation coefficient (r2) of 0.84, Broad Band Cavity Enhanced Absorption Spectroscopy (BBCEAS) (r2 = 0.75), solid phase micro extraction (SPME) (r2 = 0.89), and a

  16. Comparison of different approaches applied in Analytic Hierarchy Process - an example of information needs of patients with rare diseases.

    PubMed

    Pauer, Frédéric; Schmidt, Katharina; Babac, Ana; Damm, Kathrin; Frank, Martin; von der Schulenburg, J-Matthias Graf

    2016-09-09

    The Analytic Hierarchy Process (AHP) is increasingly used to measure patient priorities. Studies have shown that there are several different approaches to data acquisition and data aggregation. The aim of this study was to measure the information needs of patients having a rare disease and to analyze the effects of these different AHP approaches. The ranking of information needs is then used to display information categories on a web-based information portal about rare diseases according to the patient's priorities. The information needs of patients suffering from rare diseases were identified by an Internet research study and a preliminary qualitative study. Hence, we designed a three-level hierarchy containing 13 criteria. For data acquisition, the differences in outcomes were investigated using individual versus group judgements separately. Furthermore, we analyzed the different effects when using the median and arithmetic and geometric means for data aggregation. A consistency ratio ≤0.2 was determined to represent an acceptable consistency level. Forty individual and three group judgements were collected from patients suffering from a rare disease and their close relatives. The consistency ratio of 31 individual and three group judgements was acceptable and thus these judgements were included in the study. To a large extent, the local ranks for individual and group judgements were similar. Interestingly, group judgements were in a significantly smaller range than individual judgements. According to our data, the ranks of the criteria differed slightly according to the data aggregation method used. It is important to explain and justify the choice of an appropriate method for data acquisition because response behaviors differ according to the method. We conclude that researchers should select a suitable method based on the thematic perspective or investigated topics in the study. Because the arithmetic mean is very vulnerable to outliers, the geometric mean

  17. Comparison of jugular and transverse facial venous sinus blood analytes in healthy and critically ill adult horses.

    PubMed

    Lascola, Kara M; Vander Werf, Karie; Freese, Stephanie; Morgera, Alison; Schaeffer, David J; Wilkins, Pamela

    2017-03-01

    To compare blood gas, electrolyte, and metabolic analysis results between blood obtained by jugular and transverse facial venous sinus (TFVS) venipuncture in healthy adult horses and sick adult horses presented for emergency evaluation. Prospective, experimental study, from June 2012 to October 2013. Large animal university teaching hospital. Ten healthy adult University-owned horses and 48 client-owned adult horses (≥2 years old) presenting to the large animal hospital emergency service for medical or surgical evaluation of systemic illness. Venipunctures (jugular vein [JV] and TFVS) were performed using preheparinized syringes and obtained prior to institution of medical therapy. Samples were analyzed in random order within a 10-minute interval using a point-of-care blood gas analyzer (NOVA Critical Care Xpress) that also reports electrolyte and metabolite results. Comparisons between venipuncture sites were analyzed using the Student's paired t-test for normally distributed data and the Wilcoxon paired test for nonnormally distributed data. Bland-Altman analysis was used to assess agreement between venipuncture sites. There were no statistically significant differences found between variables for JV and TFVS in healthy horses. In sick horses, JV measurements were greater than TFVS for ionized calcium (P = 0.002) and glucose (P = 0.001), and less than TFVS for hematocrit (P = 0.015). Bland-Altman plots demonstrated small biases but overall agreement between sites. The TFVS can be used interchangeably with JV for venous blood gas analysis in healthy horses. In sick horses, identified differences were small and likely not clinically important. The reliability of this point-of-care blood gas analyzer for measurement of hematocrit remains to be determined. © Veterinary Emergency and Critical Care Society 2017.

  18. Stable oxygen isotopes from theropod dinosaur tooth enamel: interlaboratory comparison of results and analytical interference by reference standards.

    PubMed

    Straight, William H; Karr, Jonathan D; Cox, Julia E; Barrick, Reese E

    2004-01-01

    Although previous work has demonstrated that biological phosphates ('biophosphates') record significant changes in delta18O associated with variations in local climate and seasonality, the repeatability of these analyses between laboratories has not previously been tested. We serially sampled enamel on four Cretaceous dinosaur teeth for phosphate delta18O analysis at up to three different facilities. With the exception of one set of unprocessed enamel samples, the material supplied to each laboratory was chemically processed to silver phosphate. Each laboratory analyzed sample sets by pyrolysis (thermochemical decomposition) in a ThermoFinnigan TC/EA attached to a ThermoFinnigan Delta Plus mass spectrometer. Significant interference between phosphate samples and the NIST reference material 8557 barium sulfate (NBS 127) distorts some of the results. Samples analyzed immediately following NBS 127 may be depleted by 6 per thousand isotopically and in instrument peak amplitude response by 80%. Substantial interference can persist over the subsequent 20 silver phosphate samples, and can influence the instrument peak amplitude response from some organic standards. Experiments using reagent-grade silver phosphate link these effects to divalent cations, particularly Ca2+ and Ba2+, which linger in the reactor and scavenge oxygen evolved from pyrolysis of subsequent samples. Unprocessed enamel includes 40 wt% calcium and self-scavenges oxygen, disrupting the isotopic measurements for the first half of a set and depleting subsequent organic standards by up to 9 per thousand. In sets without NBS 127 or calcium, such interference did not occur and an interlaboratory comparison of results from enamel shows reproducible, significantly correlated peaked delta18O patterns with a 2-3 per thousand dynamic range, consistent with previous results from contemporaneous teeth. Whereas both unprocessed enamel and the NBS 127 barium sulfate should be applied to biological phosphate

  19. Comparison of Four ChIP-Seq Analytical Algorithms Using Rice Endosperm H3K27 Trimethylation Profiling Data

    PubMed Central

    Bridges, Susan M.; Peng, Zhaohua

    2011-01-01

    Chromatin immunoprecipitation coupled with high throughput DNA Sequencing (ChIP-Seq) has emerged as a powerful tool for genome wide profiling of the binding sites of proteins associated with DNA such as histones and transcription factors. However, no peak calling program has gained consensus acceptance by the scientific community as the preferred tool for ChIP-Seq data analysis. Analyzing the large data sets generated by ChIP-Seq studies remains highly challenging for most molecular biology laboratories. Here we profile H3K27me3 enrichment sites in rice young endosperm using the ChIP-Seq approach and analyze the data using four peak calling algorithms (FindPeaks, PeakSeq, USeq, and MACS). Comparison of the four algorithms reveals that these programs produce very different peaks in terms of peak size, number, and position relative to genes. We verify the peak predictions using ChIP-PCR to evaluate the accuracy of peak prediction of the four algorithms. We discuss the approach of each algorithm and compare similarities and differences in the results. Despite their differences in the peaks identified, all of the programs reach similar conclusions about the effect of H3K27me3 on gene expression. Its presence either upstream or downstream of a gene is predominately associated with repression of the gene. Additionally, GO analysis finds that a substantially higher ratio of genes associated with H3K27me3 were involved in multicellular organism development, signal transduction, response to external and endogenous stimuli, and secondary metabolic pathways than the rest of the rice genome. PMID:21984925

  20. Multicenter Comparison Study of both Analytical and Clinical Performance across Four Roche Hepatitis C Virus RNA Assays Utilizing Different Platforms.

    PubMed

    Vermehren, Johannes; Stelzl, Evelyn; Maasoumy, Benjamin; Michel-Treil, Veronique; Berkowski, Caterina; Marins, Ed G; Paxinos, Ellen E; Marino, Enrique; Wedemeyer, Heiner; Sarrazin, Christoph; Kessler, Harald H

    2017-04-01

    The efficacy of antiviral treatment for chronic hepatitis C virus (HCV) infection is determined by measuring HCV RNA at specific time points throughout therapy using highly sensitive and accurate HCV RNA assays. This study compared the performances of two recently developed real-time PCR HCV RNA assays, cobas HCV for use on the cobas 6800/8800 systems (cobas 6800/8800 HCV) and cobas HCV for use on the cobas 4800 system (cobas 4800 HCV), with those of two established assays, the Cobas AmpliPrep/Cobas TaqMan HCV quantitative test, version 2 (CAP/CTM v2) and the Cobas TaqMan HCV test, version 2 for use with the High Pure system (HPS/CTM v2). The limits of detection (LODs) and linearity at lower concentrations (5 to 1000 IU/ml) were assessed for cobas 6800/8800 HCV and cobas 4800 HCV using WHO standard traceable panels representing HCV genotypes (GT) 1 to 4. Pairwise assay comparisons were also performed using 245 clinical samples representing HCV GT 1 to GT 4. Results from cobas 6800/8800 HCV and cobas 4800 HCV were linear at low HCV RNA concentrations (<0.3 log10 IU/ml difference between expected and observed results) with LODs of 8.2 IU/ml and 11.7 IU/ml, respectively, for GT 1. The new assays showed excellent agreement with results from CAP/CTM v2 and HPS/CTM v2 in samples with quantifiable viral loads. The concordances using the 6 million IU/ml cutoff were high among all four assays (90 to 94%). In conclusion, the cobas 6800/8800 HCV and cobas 4800 HCV tests are sensitive and linear and correlate well with the established Roche assays used in clinical practice. Copyright © 2017 Vermehren et al.

  1. Multicenter Comparison Study of both Analytical and Clinical Performance across Four Roche Hepatitis C Virus RNA Assays Utilizing Different Platforms

    PubMed Central

    Vermehren, Johannes; Stelzl, Evelyn; Maasoumy, Benjamin; Michel-Treil, Veronique; Berkowski, Caterina; Marins, Ed G.; Paxinos, Ellen E.; Marino, Enrique; Wedemeyer, Heiner; Sarrazin, Christoph

    2017-01-01

    ABSTRACT The efficacy of antiviral treatment for chronic hepatitis C virus (HCV) infection is determined by measuring HCV RNA at specific time points throughout therapy using highly sensitive and accurate HCV RNA assays. This study compared the performances of two recently developed real-time PCR HCV RNA assays, cobas HCV for use on the cobas 6800/8800 systems (cobas 6800/8800 HCV) and cobas HCV for use on the cobas 4800 system (cobas 4800 HCV), with those of two established assays, the Cobas AmpliPrep/Cobas TaqMan HCV quantitative test, version 2 (CAP/CTM v2) and the Cobas TaqMan HCV test, version 2 for use with the High Pure system (HPS/CTM v2). The limits of detection (LODs) and linearity at lower concentrations (5 to 1000 IU/ml) were assessed for cobas 6800/8800 HCV and cobas 4800 HCV using WHO standard traceable panels representing HCV genotypes (GT) 1 to 4. Pairwise assay comparisons were also performed using 245 clinical samples representing HCV GT 1 to GT 4. Results from cobas 6800/8800 HCV and cobas 4800 HCV were linear at low HCV RNA concentrations (<0.3 log10 IU/ml difference between expected and observed results) with LODs of 8.2 IU/ml and 11.7 IU/ml, respectively, for GT 1. The new assays showed excellent agreement with results from CAP/CTM v2 and HPS/CTM v2 in samples with quantifiable viral loads. The concordances using the 6 million IU/ml cutoff were high among all four assays (90 to 94%). In conclusion, the cobas 6800/8800 HCV and cobas 4800 HCV tests are sensitive and linear and correlate well with the established Roche assays used in clinical practice. PMID:28122870

  2. Ultrasonographic differentiation of malignant from benign breast lesions: a meta-analytic comparison of elasticity and BIRADS scoring.

    PubMed

    Sadigh, Gelareh; Carlos, Ruth C; Neal, Colleen H; Dwamena, Ben A

    2012-05-01

    There has been controversy regarding the accuracy of breast ultrasound elastography (USE) compared to conventional B-mode Ultrasound (USB). The purpose of this study was to conduct a direct comparative effectiveness analysis of USB versus USE or their combination in differentiating breast lesions through systematically reviewing recent literature. An extensive literature search of PubMed and other medical and general purpose databases from inception through August 2011 was conducted. Published studies that reported a direct comparison of the diagnostic performance of USE, using elasticity score versus USB, using breast imaging reporting and data system (BIRADS) for characterization of focal breast lesions were included. Summary diagnostic performance measures were assessed for each of the tests and their combination using bivariate generalized linear mixed modeling. The two tests were combined as: (1) conjunctive, where the outcome of the combination of tests is positive only if both test results are positive; (2) disjunctive, where the outcome of a combination of tests is negative only if both tests are negative. Twenty nine studies provided relevant information on 5,511 breast masses (2,065 cancers, 3,446 benign lesions). Sensitivity of USB, USE, and their conjunctive and disjunctive combinations were 96% (95% credible interval (CrI), 93-98%), 79% (95% CrI, 74-83%), 73% (95% CrI, 67-78%), and 99% (95% CrI, 98-99%), respectively. Specificity of USB, USE, and their conjunctive and disjunctive combinations were 70% (95% CrI, 55-83%), 88% (95% CrI, 82-92%), 97% (95% CrI, 95-99%), and 56% (95% CrI, 43-69%), respectively. The application of USE as a single test is not superior to USB alone. However, in low risk patients it is recommended to perform an USE following a positive USB result to decrease the rate of unnecessary biopsies.

  3. Compositional and Microstructural Evolution of Olivine Under Multiple-Cycle Pulsed Laser Irradiation as Revealed by FIB/Field-Emission TEM

    NASA Technical Reports Server (NTRS)

    Christoffersen, R.; Loeffler, M. J.; Dukes, C. A.; Keller, L. P.; Baragiola, R. A.

    2016-01-01

    The use of pulsed laser irradiation to simulate the short duration, high-energy conditions characteristic of micrometeorite impacts is now an established approach in experimental space weathering studies. The laser generates both melt and vapor deposits that contain nanophase metallic Fe (npFe(sup 0)) grains with size distributions and optical properties similar to those in natural impact-generated melt and vapor deposits. There remains uncertainty, however, about how well lasers simulate the mechanical work and internal (thermal) energy partitioning that occurs in actual impacts. We are currently engaged in making a direct comparison between the products of laser irradiation and experimental/natural hypervelocity impacts. An initial step reported here is to use analytical SEM and TEM is to attain a better understanding of how the microstructure and composition of laser deposits evolve over multiple cycles of pulsed laser irradiation.

  4. How to improve the performances of Fecal Immunological Tests (FIT): Need for standardization of the sampling and pre-analytical phases and revision of the procedures for comparison of methods.

    PubMed

    Rapi, Stefano; Rubeca, Tiziana; Fraser, Callum G

    2015-02-24

    Lack of reference materials and standard procedures, on faecal tests leads to major problems in harmonisation of methods and do not allow the comparison of outcome data. In particular the absence of standardisation of pre-analytical characteristic was noted for faecal test methods for haemoglobin since different manufacturers have developed different sampling procedures and report units. Moreover the physical characteristics of the faecal specimen and the designs of specimen collection devices do not allow analysis of samples on different systems in consequence, faecal tests cannot be compared using standard evaluation protocols. To improve the harmonization of results generated using different analytical systems and the overall performances of test on faecal materials we propose the introduction of standard procedures for sampling and pre-analytical phase and the adoption of specific procedures based on the use of artificial biological samples for comparison of methods. Harmonization of sampling devices with the use of a standard design for pickers and a standard ratio between analyte and buffer for different manufacturers represent a mandatory step in the roadmap for harmonization of clinical laboratory measurement on faecal materials and can allow a significant standardisation of results generated by different devices.The creation of specific protocols for the evaluation and comparison of analytical methods for analyse of faeces could lead to a significant improvement in the performance of methods and systems.

  5. Analytic materials

    NASA Astrophysics Data System (ADS)

    Milton, Graeme W.

    2016-11-01

    The theory of inhomogeneous analytic materials is developed. These are materials where the coefficients entering the equations involve analytic functions. Three types of analytic materials are identified. The first two types involve an integer p. If p takes its maximum value, then we have a complete analytic material. Otherwise, it is incomplete analytic material of rank p. For two-dimensional materials, further progress can be made in the identification of analytic materials by using the well-known fact that a 90° rotation applied to a divergence-free field in a simply connected domain yields a curl-free field, and this can then be expressed as the gradient of a potential. Other exact results for the fields in inhomogeneous media are reviewed. Also reviewed is the subject of metamaterials, as these materials provide a way of realizing desirable coefficients in the equations.

  6. Analytic materials.

    PubMed

    Milton, Graeme W

    2016-11-01

    The theory of inhomogeneous analytic materials is developed. These are materials where the coefficients entering the equations involve analytic functions. Three types of analytic materials are identified. The first two types involve an integer p. If p takes its maximum value, then we have a complete analytic material. Otherwise, it is incomplete analytic material of rank p. For two-dimensional materials, further progress can be made in the identification of analytic materials by using the well-known fact that a 90(°) rotation applied to a divergence-free field in a simply connected domain yields a curl-free field, and this can then be expressed as the gradient of a potential. Other exact results for the fields in inhomogeneous media are reviewed. Also reviewed is the subject of metamaterials, as these materials provide a way of realizing desirable coefficients in the equations.

  7. Persistence of TEM-52/TEM-92 and SHV-12 extended-spectrum β-lactamases in clinical isolates of Enterobacteriaceae in Italy.

    PubMed

    Perilli, Mariagrazia; Segatore, Bernardetta; Mugnaioli, Claudia; Celenza, Giuseppe; Rossolini, Gian Maria; Stefani, Stefania; Luzzaro, Francesco; Pini, Beatrice; Amicosante, Gianfranco

    2011-12-01

    Extended-spectrum β-lactamases (ESBLs) belonging to the TEM and SHV families were investigated in 583 ESBL-producing Enterobacteriaceae collected at the clinical microbiology laboratories of 11 teaching Italian hospitals. By molecular analysis TEM-type and SHV-type ESBLs were confirmed on 154 and 74 isolates, respectively. High variability was found among TEM-types β-lactamases with the following variants: TEM-5, TEM-6, TEM-12, TEM-15, TEM-24, TEM-26, TEM-29, TEM-52, TEM-92, TEM-134, and TEM-149. Among SHV variants, SHV-2a, SHV-5, SHV-12, and SHV-28 have been detected. The most widespread variants are TEM-52/92 and SHV-12.

  8. Nanoparticle embedded chitosan film for agglomeration free TEM images.

    PubMed

    Dogan, Üzeyir; Çiftçi, Hakan; Cetin, Demet; Suludere, Zekiye; Tamer, Ugur

    2017-02-01

    Transmission electron microscopy (TEM) is a very useful and commonly used microscopy technique, used especially for the characterization of nanoparticles. However, the identification of the magnetic nanoparticle could be thought problematic in TEM analysis, due to the fact that the magnetic nanoparticles are usually form aggregates on the TEM grid to form bigger particles generating higher stability. This prevents to see exact shape and size of each nanoparticle. In order to overcome this problem, a simple process for the formation of well-dispersed nanoparticles was conducted, by covering chitosan film on the unmodified copper grid, it was said to result in aggregation-free TEM images. It is also important to fix the magnetic nanoparticles on the TEM grids, due to possible contamination of TEM filament which is operated under high vacuum conditions. The chitosan film matrix also helps to protect the TEM filament from contact with magnetic nanoparticles during the imaging process. The proposed procedure offers a quick method to fix the nanoparticles in a conventional copper TEM grid and chitosan matrix prevents agglomeration of nanoparticles, and thus getting TEM images showing well-dispersed individual nanoparticles. © 2016 Wiley Periodicals, Inc.

  9. Characterization of the Novel CMT Enzyme TEM-154.

    PubMed

    Robin, Frédéric; Delmas, Julien; Machado, Elisabete; Bouchon, Bernadette; Peixe, Luísa; Bonnet, Richard

    2011-03-01

    TEM-154, identified in Portugal in 2004, associated the substitutions observed in the extended-spectrum β-lactamase (ESBL) TEM-12 and in the inhibitor-resistant penicillinase (IRT) TEM-33. This enzyme exhibited hydrolytic activity against ceftazidime and a low level of resistance to clavulanic acid. Surprisingly, the substitution Met69Leu enhanced the catalytic efficiency of oxyimino β-lactams conferred by the substitution Arg164Ser. Its discovery confirms the dissemination of the complex mutant group of TEM enzymes in European countries.

  10. Functional comparisons between unimodal and bimodal analytical relationships in terms of water balance predictions for the case study of the Vesuvius volcanic area (Naples, Southern Italy).

    NASA Astrophysics Data System (ADS)

    Romano, Nunzio; Nasta, Paolo

    2015-04-01

    Optimal performance of large-scale numerical modeling of the soil-vegetation-atmosphere (SVA) system mandates accurate assessment and description of the soil hydraulic properties, namely the water retention (WRF) and hydraulic conductivity (HCF) functions. These functions are commonly described by simple unimodal analytical relations that guarantee mathematical flexibility with few parameters in the majority of soil types. However, other soils, like volcanic soils, are characterized by a complex structure yielding a bimodal or even a multimodal distribution of pore sizes. In these cases, reliable hydrologic predictions can be obtained resorting to more complex hydraulic functions, yet more accurate and robust ones. To overcome some drawbacks of the classic unimodal hydraulic relationships, Romano et al. (2011) have developed closed-form bimodal lognormal relations for improving the description of both WRF and HCF. However, the reliability of this description of the soil hydraulic behavior is often tested at the curve fitting level only. Comparisons between unimodal and bimodal soil hydraulic relationships are more effective and informative when performed in functional terms. Therefore, as the primary objective of this study, we used a hydrological balance model to quantify and compare soil moisture flow and storage regimes for 14 years (1999-2012), when characterized by unimodal or bimodal approximations of 39 measured soil water retention and hydraulic conductivity characteristics collected in volcanic Vesuvian soil located in the Campania Region Plain (Naples, Southern Italy).

  11. The Structural Bases of Antibiotic Resistance in the Clinically Derived Mutant beta-Lactamases TEM-30, TEM-32, and TEM-34

    SciTech Connect

    Wang, Xiaojun; Minasov, George; Shoichet, Brian K.

    2010-03-08

    Widespread use of {beta}-lactam antibiotics has promoted the evolution of {beta}-lactamase mutant enzymes that can hydrolyze ever newer classes of these drugs. Among the most pernicious mutants are the inhibitor-resistant TEM {beta}-lactamases (IRTs), which elude mechanism-based inhibitors, such as clavulanate. Despite much research on these IRTs, little is known about the structural bases of their action. This has made it difficult to understand how many of the resistance substitutions act as they often occur far from Ser-130. Here, three IRT structures, TEM-30 (R244S), TEM-32 (M69I/M182T), and TEM-34 (M69V), are determined by x-ray crystallography at 2.00, 1.61, and 1.52 {angstrom}, respectively. In TEM-30, the Arg-244 {yields} Ser substitution (7.8 {angstrom} from Ser-130) displaces a conserved water molecule that usually interacts with the {beta}-lactam C3 carboxylate. In TEM-32, the substitution Met-69 {yields} Ile (10 {angstrom} from Ser-130) appears to distort Ser-70, which in turn causes Ser-130 to adopt a new conformation, moving its O{gamma} further away, 2.3 {angstrom} from where the inhibitor would bind. This substitution also destabilizes the enzyme by 1.3 kcal/mol. The Met-182 {yields} Thr substitution (20 {angstrom} from Ser-130) has no effect on enzyme activity but rather restabilizes the enzyme by 2.9 kcal/mol. In TEM-34, the Met-69 {yields} Val substitution similarly leads to a conformational change in Ser-130, this time causing it to hydrogen bond with Lys-73 and Lys-234. This masks the lone pair electrons of Ser-130 O{gamma}, reducing its nucleophilicity for cross-linking. In these three structures, distant substitutions result in accommodations that converge on the same point of action, the local environment of Ser-130. TEM-1 {beta}-lactamase is the predominant source of resistance to {beta}-lactams, such as the penicillins. TEM-1 and related class A {beta}-lactamases confer resistance by hydrolyzing the {beta}-lactam ring of these antibiotics

  12. Updated Sequence Information for TEM β-Lactamase Genes

    PubMed Central

    Goussard, Sylvie; Courvalin, Patrice

    1999-01-01

    The sequences of the promoter regions and of the structural genes for 13 penicillinase, extended-spectrum, and inhibitor-resistant TEM-type β-lactamases have been determined, and an updated blaTEM gene nomenclature is proposed. PMID:9925535

  13. Design, fabrication, and applications of in situ fluid cell TEM.

    PubMed

    Li, Dongsheng; Nielsen, Michael H; De Yoreo, James J

    2013-01-01

    In situ fluid cell TEM is a powerful new tool for understanding dynamic processes during liquid phase chemical reactions, including mineral formation. This technique, which operates in the high vacuum of a TEM chamber, provides information on crystal structure, phase, morphology, size, aggregation/segregation, and crystal growth mechanisms in real time. In situ TEM records both crystal structure and morphology at spatial resolutions down to the atomic level with high temporal resolution of up to 10(-6)s per image, giving it distinct advantages over other in situ techniques such as optical microscopy, AFM, or X-ray scattering or diffraction. This chapter addresses the design, fabrication, and assembly of TEM fluid cells and applications of fluid cell TEM to understanding mechanisms of mineralization. © 2013 Elsevier Inc. All rights reserved.

  14. Recognition and Resistance in TEM [superscript beta]-Lactamase

    SciTech Connect

    Wang, Xiaojun; Minasov, George; Blazquez, Jesus; Caselli, Emilia; Prati, Fabio; Shoichet, Brian K.

    2010-03-08

    Developing antimicrobials that are less likely to engender resistance has become an important design criterion as more and more drugs fall victim to resistance mutations. One hypothesis is that the more closely an inhibitor resembles a substrate, the more difficult it will be to develop resistant mutations that can at once disfavor the inhibitor and still recognize the substrate. To investigate this hypothesis, 10 transition-state analogues, of greater or lesser similarity to substrates, were tested for inhibition of TEM-1 beta-lactamase, the most widespread resistance enzyme to penicillin antibiotics. The inhibitors were also tested against four characteristic mutant enzymes: TEM-30, TEM-32, TEM-52, and TEM-64. The inhibitor most similar to the substrate, compound 10, was the most potent inhibitor of the WT enzyme, with a K(i) value of 64 nM. Conversely, compound 10 was the most susceptible to the TEM-30 (R244S) mutant, for which inhibition dropped by over 100-fold. The other inhibitors were relatively impervious to the TEM-30 mutant enzyme. To understand recognition and resistance to these transition-state analogues, the structures of four of these inhibitors in complex with TEM-1 were determined by X-ray crystallography. These structures suggest a structural basis for distinguishing inhibitors that mimic the acylation transition state and those that mimic the deacylation transition state; they also suggest how TEM-30 reduces the affinity of compound 10. In cell culture, this inhibitor reversed the resistance of bacteria to ampicillin, reducing minimum inhibitory concentrations of this penicillin by between 4- and 64-fold, depending on the strain of bacteria. Notwithstanding this activity, the resistance of TEM-30, which is already extant in the clinic, suggests that there can be resistance liabilities with substrate-based design.

  15. Analytical Electron Microscopy examination of uranium contamination at the DOE Fernald operation site

    SciTech Connect

    Buck, E.C.; Dietz, N.L.; Bates, J.K.; Cunnane, J.C.

    1993-02-01

    Analytical Electron Microscopy (AEM) has been used to identify uranium-bearing phases present in contaminated soils from the DOE Fernald operation site. A combination of optical microscopy, scanning electron microscopy with backscattered electron detection (SEM/BSE), and AEM was used in isolating and characterizing uranium-rich regions of the contaminated soils. Soil samples were prepared for transmission electron microscopy (TEM) by ultramicrotomy using an embedding resin previously employed for aquatic colloids and biological samples. This preparation method allowed direct comparison between SEM and TEM images. At the macroscopic level much of the uranium appears to be associated with clays in the soils; however, electron beam analysis revealed that the uranium is present as discrete phases, including iron oxides, silicates (soddyite), phosphates (autunites), and fluorite. Only low levels of uranium were actually within the clay minerals. The distribution of uranium phases was inhomogeneous at the submicron level.

  16. Multielement trace determination in SiC powders: assessment of interlaboratory comparisons aimed at the validation and standardization of analytical procedures with direct solid sampling based on ETV ICP OES and DC arc OES.

    PubMed

    Matschat, Ralf; Hassler, Jürgen; Traub, Heike; Dette, Angelika

    2005-12-01

    The members of the committee NMP 264 "Chemical analysis of non-oxidic raw and basic materials" of the German Standards Institute (DIN) have organized two interlaboratory comparisons for multielement determination of trace elements in silicon carbide (SiC) powders via direct solid sampling methods. One of the interlaboratory comparisons was based on the application of inductively coupled plasma optical emission spectrometry with electrothermal vaporization (ETV ICP OES), and the other on the application of optical emission spectrometry with direct current arc (DC arc OES). The interlaboratory comparisons were organized and performed in the framework of the development of two standards related to "the determination of mass fractions of metallic impurities in powders and grain sizes of ceramic raw and basic materials" by both methods. SiC powders were used as typical examples of this category of material. The aim of the interlaboratory comparisons was to determine the repeatability and reproducibility of both analytical methods to be standardized. This was an important contribution to the practical applicability of both draft standards. Eight laboratories participated in the interlaboratory comparison with ETV ICP OES and nine in the interlaboratory comparison with DC arc OES. Ten analytes were investigated by ETV ICP OES and eleven by DC arc OES. Six different SiC powders were used for the calibration. The mass fractions of their relevant trace elements were determined after wet chemical digestion. All participants followed the analytical requirements described in the draft standards. In the calculation process, three of the calibration materials were used successively as analytical samples. This was managed in the following manner: the material that had just been used as the analytical sample was excluded from the calibration, so the five other materials were used to establish the calibration plot. The results from the interlaboratory comparisons were summarized and

  17. Analytical testing

    NASA Technical Reports Server (NTRS)

    Flannelly, W. G.; Fabunmi, J. A.; Nagy, E. J.

    1981-01-01

    Analytical methods for combining flight acceleration and strain data with shake test mobility data to predict the effects of structural changes on flight vibrations and strains are presented. This integration of structural dynamic analysis with flight performance is referred to as analytical testing. The objective of this methodology is to analytically estimate the results of flight testing contemplated structural changes with minimum flying and change trials. The category of changes to the aircraft includes mass, stiffness, absorbers, isolators, and active suppressors. Examples of applying the analytical testing methodology using flight test and shake test data measured on an AH-1G helicopter are included. The techniques and procedures for vibration testing and modal analysis are also described.

  18. Multiplexed TEM Specimen Preparation and Analysis of Plasmonic Nanoparticles.

    PubMed

    Mulligan, Sean K; Speir, Jeffrey A; Razinkov, Ivan; Cheng, Anchi; Crum, John; Jain, Tilak; Duggan, Erika; Liu, Er; Nolan, John P; Carragher, Bridget; Potter, Clinton S

    2015-08-01

    We describe a system for rapidly screening hundreds of nanoparticle samples using transmission electron microscopy (TEM). The system uses a liquid handling robot to place up to 96 individual samples onto a single standard TEM grid at separate locations. The grid is then transferred into the TEM and automated software is used to acquire multiscale images of each sample. The images are then analyzed to extract metrics on the size, shape, and morphology of the nanoparticles. The system has been used to characterize plasmonically active nanomaterials.

  19. Multiplexed TEM Specimen Preparation and Analysis of Plasmonic Nanoparticles

    PubMed Central

    Cheng, Anchi; Crum, John; Jain, Tilak; Duggan, Erika; Liu, Er; Nolan, John P.; Carragher, Bridget; Potter, Clinton S.

    2015-01-01

    We describe a system for rapidly screening hundreds of nanoparticle samples using transmission electron microscopy (TEM). The system uses a liquid handling robot to place up to 96 individual samples onto a single standard TEM grid at separate locations. The grid is then transferred into the TEM and automated software is used to acquire multi-scale images of each sample. The images are then analyzed to extract metrics on the size, shape, and morphology of the nanoparticles. The system has been used to characterize plasmonically-active nanomaterials. PMID:26223550

  20. Molecular dynamics simulations and morphology analysis of TEM imaged PVDF nanofibers

    NASA Astrophysics Data System (ADS)

    Miao, Jiayuan; Reneker, Darrell; Tsige, Mesfin; Taylor, Philip

    With the goal of elucidating the structure of polyvinylidene fluoride (PVDF) nanofibers, all-atom molecular dynamics simulations were performed, and the results compared with structures observed in high resolution transmission electron microscopy (TEM) at the molecular level. Simulation shows that the stability of the β-phase component in a PVDF nanofiber is influenced by its thickness and processing history. When exposed to irradiation, as in a TEM observation, the structure is then further modified by the effects of chain scission. The transformation from the β phase into a paraelectric phase can explain the spindle formation and serpentine motion of molecular segments observed by Zhong et al. (Polymer, 54, 2013, 3745-3756) in irradiated PVDF nanofibers. From a comparison between simulated and experimental TEM images it was possible to identify numerous features that are useful in unveiling the inherent structure of PVDF nanofibers. The experimental TEM images appear to match well with those predicted by a model based on α-phase PVDF, while also being consistent with an alternative model (Nanoscale 2015, DOI: 10.1039/c5nr01619c). Work supported by the Petroleum Research Fund of the ACS.

  1. Appendix B: Summary of TEM Particle Size Distribution Datasets

    EPA Pesticide Factsheets

    As discussed in the main text (see Section 5.3.2), calculation of the concentration of asbestos fibers in each of the bins of potential interest requires particle size distribution data derived using transmission electron microscopy (TEM).

  2. Coordinated Isotopic and TEM Studies of Presolar Graphites from Murchison

    NASA Astrophysics Data System (ADS)

    Croat, T. K.; Stadermann, F. J.; Zinner, E.; Bernatowicz, T. J.

    2004-03-01

    TEM and NanoSIMS investigations of the same presolar Murchison KFC graphites revealed high Zr, Mo, and Ru content in refractory carbides within the graphites. Along with isotopically light carbon, these suggest a low-metallicity AGB source.

  3. Preparation of carbon-free TEM microgrids by metal sputtering.

    PubMed

    Janbroers, S; de Kruijff, T R; Xu, Q; Kooyman, P J; Zandbergen, H W

    2009-08-01

    A new method for preparing carbon-free, temperature-stable Transmission Electron Microscope (TEM) grids is presented. An 80% Au/20% Pd metal film is deposited onto a 'holey' microgrid carbon supported on standard mixed-mesh Au TEM grids. Subsequently, the carbon film is selectively removed using plasma cleaning. In this way, an all-metal TEM film is made containing the 'same' microgrid as the original carbon film. Although electron transparency of the foil is reduced significantly, the open areas for TEM inspection of material over these areas are maintained. The metal foil can be prepared with various thicknesses and ensures good electrical conductivity. The new Au/Pd grids are stable to at least 775K under vacuum conditions.

  4. Instability of nanoscale metallic particles under electron irradiation in TEM

    NASA Astrophysics Data System (ADS)

    Chen, X. Y.; Zhang, S. G.; Xia, M. X.; Li, J. G.

    2016-03-01

    The stability of nano metallic glass under electron beam in transmission electron microscope (TEM) was investigated. The most common voltage of TEM used in metallic materials characterization was either 200 kV or 300 kV. Both situations were investigated in this work. An amorphous metallic particle with a dimension of a few hundred nanometers was tested under 300 keV electron irradiation. New phase decomposed from the parent phase was observed. Moreover, a crystal particle with the same composition and dimension was tested under 200 keV irradiation. Decomposition process also occurred in this situation. Besides, crystal orientation modification was observed during irradiation. These results proved that the electron beam in TEM have an effect on the stability of nanoscale samples during long time irradiation. Atomic displacement was induced and diffusion was enhanced by electron irradiation. Thus, artifacts would be induced when a nanoscale metallic sample was characterized in TEM.

  5. TEM Study of Internal Crystals in Supernova Graphites

    NASA Astrophysics Data System (ADS)

    Croat, T. K.; Bernatowicz, T.; Stadermann, F. J.; Messenger, S.; Amari, S.

    2003-03-01

    A coordinated TEM and isotopic study of ten supernova (SN) graphites from the Murchison meteorite has revealed many internal grains, mostly titanium carbides (TiCs) and TiC-kamacite composite grains, which were accreted during the graphite growth.

  6. Analytical Microscopy

    SciTech Connect

    Not Available

    2006-06-01

    In the Analytical Microscopy group, within the National Center for Photovoltaic's Measurements and Characterization Division, we combine two complementary areas of analytical microscopy--electron microscopy and proximal-probe techniques--and use a variety of state-of-the-art imaging and analytical tools. We also design and build custom instrumentation and develop novel techniques that provide unique capabilities for studying materials and devices. In our work, we collaborate with you to solve materials- and device-related R&D problems. This sheet summarizes the uses and features of four major tools: transmission electron microscopy, scanning electron microscopy, the dual-beam focused-ion-beam workstation, and scanning probe microscopy.

  7. A High-Power Reflector Impulse Antenna with Dual-Tem Source

    NASA Astrophysics Data System (ADS)

    Guo, Chen; Zhang, An-Xue; Wu, Hui; Jiang, Yan-Sheng; Wang, Wen-Bing

    2008-09-01

    There are different demands on radiation efficiency and direction pattern according to various ultra-wideband (UWB) antennas and high power applications. To obtain more radiating gain on bore-sight of paraboloidal reflector and centralized radiating direction, a novel feeding structure called dual-TEM source has been designed and applied in half-paraboloidal reflector impulse radiating antenna (IRA) applications. Simulation results proved that this proposed half-paraboloidal reflector IRA with dual-TEM source provided greater radiation performance on bore-sight as a result of the synthesized power in the aperture space of paraboloid. Moreover, lots of simulation work and comparison have been done in different feeding models to summarize a relative optimal feeding structure.

  8. R164H and V240H replacements by site-directed mutagenesis of TEM-149 extended-spectrum β-lactamase: kinetic analysis of TEM-149H240 and TEM-149H164-H240 laboratory mutants.

    PubMed

    Perilli, Mariagrazia; Celenza, Giuseppe; Mercuri, Paola Sandra; Galleni, Moreno; Pellegrini, Cristina; Segatore, Bernardetta; Amicosante, Gianfranco

    2013-02-01

    Two laboratory mutant forms, TEM-149(H240) and TEM-149(H164-H240), of the TEM-149 extended-spectrum β-lactamase enzyme were constructed by site-directed mutagenesis. TEM-149(H240) and TEM-149(H164-H240) were similar in kinetic behavior, except with respect to benzylpenicillin and ceftazidime. Molecular modeling of the two mutant enzymes demonstrated the role of histidine at position 240 in the reduction of the affinity of the enzyme for ceftazidime.

  9. Compositional and Microstructural Evolution of Olivine During Pulsed Laser Irradiation: Insights Based on a FIB/Field-Emission TEM Study

    NASA Technical Reports Server (NTRS)

    Christoffersen, R.; Loeffler, M. J.; Dukes, C. A.; Baragiola, R. A.

    2015-01-01

    Introduction: The use of pulsed laser irradiation to simulate the short duration, high-energy conditions characteristic of micrometeorite impacts is now an established approach in experimental space weathering studies. The laser generates both melt and vapor deposits that contain nanophase metallic Fe (npFe(sup 0)) grains with size distributions and optical properties similar to those in natural impact-generated melt and vapor deposits. There remains uncertainty, however, about how well lasers simulate the mechanical work and internal (thermal) energy partitioning that occurs in actual impacts. We are currently engaged in making a direct comparison between the products of laser irradiation and experimental/natural hypervelocity impacts. An initial step reported here is to use analytical TEM is to attain a better understanding of how the microstructure and composition of laser deposits evolve over multiple cycles of pulsed laser irradiation. Experimental Methods: We irradiated pressed-powder pellets of San Carlos olivine (Fo(sub 90)) with up to 99 rastered pulses of a GAM ArF excimer laser. The irradiated surface of the sample were characterized by SEM imaging and areas were selected for FIB cross sectioning for TEM study using an FEI Quanta dual-beam electron/focused ion beam instrument. FIB sections were characterized using a JEOL2500SE analytical field-emission scanning transmission electron microscope (FE-STEM) optimized for quantitative element mapping at less than 10 nm spatial resolutions. Results: In the SEM the 99 pulse pressed pellet sample shows a complex, inhomogeneous, distribution of laser-generated material, largely concentrated in narrow gaps and larger depressions between grains. Local concentrations of npFe0 spherules 0.1 to 1 micrometers in size are visible within these deposits in SEM back-scatter images. Fig. 1 shows bright-field STEM images of a FIB cross-section of a one of these deposits that continuously covers the top and sloping side of an

  10. In-situ TEM observation on STM tunneling gap

    NASA Astrophysics Data System (ADS)

    Kim, Suhyun; Tanishiro, Yasumasa; Takayanagi, Kunio

    2009-03-01

    Transmission Electron Microscope and Scanning Tunneling Microscope in an ultra high vacuum environment (UHV-TEM-STM) have been combined to simultaneously perform both high resolution TEM and atomically resolved STM experiments. This system was constructed for in-situ investigation of physical property of impurity atoms embedded below semiconductor surface. To image TEM and STM at the same time, crucial requirement is that, the STM image must be acquired under the electron beam irradiation. As a preliminary test, we used HOPG (Highly Oriented Pyrolytic Graphite) sample and tungsten tip as schematically shown in Fig 1(a). Fig 1(b) shows an atomic resolution STM image of HOPG obtained with 300mV sample bias and 3nA tunneling current even in the condition of the electron beam irradiation on the tip. TEM image can be simultaneously acquired by performing In-situ TEM observation on STM tunneling gap formed between the tip and a thin sample. Fig 1(a) Geometry of STM observation on STM tunneling gap Fig 1(b) STM image of HOPG obtained with 300mV sample bias and 3nA tunneling current

  11. Novel sample preparation for operando TEM of catalysts.

    PubMed

    Miller, Benjamin K; Barker, Trevor M; Crozier, Peter A

    2015-09-01

    A new TEM sample preparation method is developed to facilitate operando TEM of gas phase catalysis. A porous Pyrex-fiber pellet TEM sample was produced, allowing a comparatively large amount of catalyst to be loaded into a standard Gatan furnace-type tantalum heating holder. The increased amount of catalyst present inside the environmental TEM allows quantitative determination of the gas phase products of a catalytic reaction performed in-situ at elevated temperatures. The product gas concentration was monitored using both electron energy loss spectroscopy (EELS) and residual gas analysis (RGA). Imaging of catalyst particles dispersed over the pellet at atomic resolution is challenging, due to charging of the insulating glass fibers. To overcome this limitation, a metal grid is placed into the holder in addition to the pellet, allowing catalyst particles dispersed over the grid to be imaged, while particles in the pellet, which are assumed to experience identical conditions, contribute to the overall catalytic conversion inside the environmental TEM cell. The gas within the cell is determined to be well-mixed, making this assumption reasonable. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. 2D TEM Modeling and Inversion by Adaptive Born Forward Mapping

    NASA Astrophysics Data System (ADS)

    Lee, T.; Seo, M.; Cho, I. K.; Ko, K. B.; You, Y. J.

    2014-12-01

    In the airborne electromagnetic survey, vast data are acquired with the development of precise measuring equipment and the automation of data acquisition. In this study we developed fast and accurate two-dimensional (2D) modeling and inversion algorithm based on the adaptive born forward mapping (ABFM) method, which is recently emerging for fast time-domain electromagnetic (TEM) modeling. The ABFM method is an approximation method that takes into consideration the true electrical conductivity distribution of subsurface media and is different from the conventional Born approximation that uses the constant electric conductivity. One of the most important points of the ABFM method is how to set a suitable sensitivity function. In this study, the known 1D sensitivity function was expanded into 2D sensitivity function to effectively approximate the dispersive behavior of electromagnetic field. By comparing the analytic solution and approximate ABFM solution for layered earth models, we found that the two solutions correspond to each other well. This implies that the 2D sensitivity function suggested in this study is suitable and that the ABFM method has very excellent accuracy in 2D TEM modeling even though it is an approximation method. Furthermore, a 2D inversion algorithm was developed with respect to the apparent conductivity data of TEM based on ABFM. To enhance the resolution and stability, the smoothness-constrained least-squares method with ACB constraint was employed. The inversion of calculated data for various models produced a reasonable model close to the true model. It is expected that the method will be extensively applicable to TEM modeling and inversion without difficulty in the future.

  13. The Asian project for collaborative derivation of reference intervals: (2) results of non-standardized analytes and transference of reference intervals to the participating laboratories on the basis of cross-comparison of test results.

    PubMed

    Ichihara, Kiyoshi; Ceriotti, Ferruccio; Kazuo, Mori; Huang, Yang-Yang; Shimizu, Yoshihisa; Suzuki, Haruki; Kitagawa, Masami; Yamauchi, Kazuyoshi; Hayashi, Sadao; Tsou, Chia-Chun; Yamamoto, Yoshikazu; Ishida, Shigeo; Leong, Linda; Sano, Michitaka; Lim, Hwan Sub; Suwabe, Akira; Woo, Hee-Yeon; Kojima, Keiya; Okubo, Yoshio

    2013-07-01

    The 2009 Asian multicenter study for derivation of reference intervals (RIs) featured: 1) centralized measurements to exclude reagent-dependent variations; 2) inclusion of non-standardized analytes (hormones, tumor makers, etc.) in the target; and 3) cross-check of test results between the central and local laboratories. Transferability of centrally derived RIs for non-standardized analytes based on the cross-check was examined. Forty non-standardized analytes were centrally measured in sera from 3541 reference individuals recruited by 63 laboratories. Forty-four laboratories collaborated in the cross-check study by locally measuring aliquots of sera from 9 to 73 volunteers (average 22.2). Linear relationships were obtained by the major-axis regression. Error in converting RIs using the regression line was expressed by the coefficient of variation of slope b [CV(b)]. CV(b) <10% was set as the cut-off value allowing the conversion. The significance of factors for partitioning RIs was determined similarly as in the first report. Significant sex-, age-, and region-related changes in test results were observed in 17, 15, and 11 of the 40 analytes, respectively. In the cross-comparison study, test results were not harmonized in the majority of immunologically measured analytes, but their average CV(b)s were <10% except for total protein, cystatin C, CA19-9, free thyroxine, and triiodothyronine. After conversion, 74% of centrally derived RIs were transferred to each local laboratory. Our results point to the feasibility of: 1) harmonizing test results across different laboratories; and 2) sharing centrally derived RIs of non-standardized analytes by means of comparative measurement of a set of commutable specimens.

  14. Hydrophilic Interaction Chromatography Hyphenated with Mass Spectrometry: A Powerful Analytical Tool for the Comparison of Originator and Biosimilar Therapeutic Monoclonal Antibodies at the Middle-up Level of Analysis.

    PubMed

    D'Atri, Valentina; Fekete, Szabolcs; Beck, Alain; Lauber, Matthew; Guillarme, Davy

    2017-02-07

    The development and approval processes of biosimilar mAbs depend on their comparability to originators. Therefore, analytical comparisons are required to assess structural features and post-translational modifications (PTM) and thereby minimize the risk of being clinically meaningful differences between biosimilar and originator drug products. The glycosylation pattern of mAbs is considered to be an important critical quality attribute (CQA), and several analytical approaches have been proposed that facilitate characterizing and monitoring a glycosylation profile, albeit mainly at a glycan and glycopeptide level of analysis. In this study, we demonstrate the utility of hydrophilic interaction chromatography (HILIC) hyphenated with mass spectrometry (MS) for the qualitative profiling of glycosylation patterns at the protein level, by comparing originator and biosimilars mAbs (Remicade/Remsina/Inflectra, Herceptin/Trastuzumab B, and Erbitux/Cetuximab B) using a middle-up approach. We demonstrate the ability of HILIC to resolve hydrophilic variants of protein biopharmaceuticals at the middle-up level of analysis, its complementarity to reversed phase liquid chromatography, and its hyphenation to MS. HILIC features combined to MS make a powerful analytical tool for the comparison of originator and biosimilar mAbs that could eventually be applied in routine analyses for quality control.

  15. In vivo selection of a complex mutant TEM (CMT) from an inhibitor-resistant TEM (IRT) during ceftazidime therapy.

    PubMed

    Jacquier, H; Marcadé, G; Raffoux, E; Dombret, H; Woerther, P L; Donay, J L; Arlet, G; Cambau, E

    2013-12-01

    A relapse from Escherichia coli bloodstream infection was observed in a patient with acute leukaemia treated with ceftazidime for 7 days for febrile neutropenia. Whereas the original E. coli isolate was resistant to β-lactam/β-lactamase inhibitor combinations (EC1), the relapse E. coli isolate showed a similar phenotype but with resistance extended to ceftazidime (EC2). We investigated the molecular mechanisms of β-lactam resistance and sought if EC2 could have been selected in vivo from EC1. EC1 and EC2 isolates were compared for antibiotic MICs, plasmid content, genotyping, β-lactamase genes and their environment. Both isolates were conjugated with E. coli JW4111ΔampC and MICs determined for transconjugants. In addition, ceftazidime-resistant mutants were selected in vitro from EC1. EC1 and EC2 showed identical patterns for genotyping and resistance plasmids. PCR sequencing of blaTEM in EC1 showed the mutations M69L and N276D corresponding to TEM-35, also called inhibitor-resistant TEM (IRT)-4. In EC2, the TEM allele showed an additional mutation, R164S, known to confer resistance to ceftazidime. The combination of these three mutations was previously reported in TEM-158, described as the complex mutant TEM (CMT)-9, associated with resistance to β-lactamase inhibitors and third-generation cephalosporins. In vitro selection of ceftazidime-resistant mutants from EC1 yielded six different CMT alleles, including TEM-158 containing the R164S mutation. This first known report of in vivo selection of CMT from IRT, reproduced in vitro, shows how the evolution of β-lactamase enzymes is easily driven by antibiotic pressure, even during a short antibiotic therapy.

  16. Analytical sedimentology

    SciTech Connect

    Lewis, D.W. . Dept. of Geology); McConchie, D.M. . Centre for Coastal Management)

    1994-01-01

    Both a self instruction manual and a cookbook'' guide to field and laboratory analytical procedures, this book provides an essential reference for non-specialists. With a minimum of mathematics and virtually no theory, it introduces practitioners to easy, inexpensive options for sample collection and preparation, data acquisition, analytic protocols, result interpretation and verification techniques. This step-by-step guide considers the advantages and limitations of different procedures, discusses safety and troubleshooting, and explains support skills like mapping, photography and report writing. It also offers managers, off-site engineers and others using sediments data a quick course in commissioning studies and making the most of the reports. This manual will answer the growing needs of practitioners in the field, either alone or accompanied by Practical Sedimentology, which surveys the science of sedimentology and provides a basic overview of the principles behind the applications.

  17. A single-tilt TEM stereomicroscopy technique for crystalline materials.

    PubMed

    McCabe, Rodney J; Misra, Amit; Mitchell, Terence E; Alexander, Kathleen B

    2003-02-01

    A new single-tilt technique for performing TEM stereomicroscopy of strain fields in crystalline materials has been developed. The technique is a weak beam technique that involves changing the value of g and/or s g while tilting across a set of Kikuchi bands. The primary benefit of the technique is it can be used with single-tilt TEM specimen holders including many specialty holders such as in situ straining, heating, and cooling holders. Standard stereo-TEM techniques are almost always limited to holders allowing two degrees of rotational freedom (i.e., double-tilt or tilt/rotation holders). An additional benefit of the new technique is that it eliminates the need to focus with the specimen height control. These advantages make it useful for stereo viewing or for quantitative stereomicroscopy provided necessary consideration is given to errors that may result from the technique.

  18. Detecting flaws in Portland cement concrete using TEM horn antennae

    NASA Astrophysics Data System (ADS)

    Al-Qadi, Imad L.; Riad, Sedki M.; Su, Wansheng; Haddad, Rami H.

    1996-11-01

    To understand the dielectric properties of PCC and better correlate them with type and severity of PCC internal defects, a study was conducted to evaluate PCC complex permittivity and magnetic permeability over a wideband of frequencies using both time domain and frequency domain techniques. Three measuring devices were designed and fabricated: a parallel plate capacitor, a coaxial transmission line, and transverse electromagnetic (TEM) horn antennae. The TEM horn antenna covers the microwave frequencies. The measurement technique involves a time domain setup that was verified by a frequency domain measurement. Portland cement concrete slabs, 60 by 75 by 14 cm, were cast; defects include delamination, delamination filled with water, segregation, and chloride contamination. In this paper, measurements using the TEM horn antennae and the feasibility of detecting flaws at microwave frequency are presented.

  19. Chromium and aluminum biosorption on Chryseomonas luteola TEM05.

    PubMed

    Ozdemir, G; Baysal, S H

    2004-05-01

    Cr(VI) and Al(III) are environmental pollutants that are frequently encountered together in industrial wastewaters, e.g., from mining iron-steel, metal cleaning, plating, metal processing, automobile parts, and the manufacturing and dye industries. In this work, several variables that affect the capacity for chromium and aluminum biosorption by Chryseomonas luteola TEM05 were studied, particularly the effects of pH, metal concentration and contact time. Optimum adsorption pH values of Cr(VI) and Al(III) were determined as 4.0 and 5.0, respectively. The biosorption equilibrium was described by Freundlich and Langmuir adsorption isotherms. The value of Qo appears to be significantly higher for the Al(III) C. luteola TEM05 system. Langmuir parameters of C. luteola TEM05 also indicated a maximum adsorption capacity of 55.2 mg g(-1) for Al(III) and 3.0 mg g(-1) for Cr(VI).

  20. Complete Tem-Tomography: 3D Structure of Gems Cluster

    NASA Technical Reports Server (NTRS)

    Matsuno, J.; Miyake, A.; Tsuchiyama, A.; Messenger, S.; Nakamura-Messenger, K.

    2015-01-01

    GEMS (glass with embedded metal and sulfide) grains in interplanetary dust particles (IDPs) are considered to be one of the ubiquitous and fundamental building blocks of solids in the Solar System. They have been considered to be interstellar silicate dust that survived various metamorphism or alteration processes in the protoplanetary disk but the elemental and isotopic composition measurements suggest that most of them have been formed in the protoplanetary disk as condensates from high temperature gas. This formation model is also supported by the formation of GEMS-like grains with respect to the size, mineral assemblage, texture and infrared spectrum by condensation experiments from mean GEMS composition materials. Previous GEMS studies were performed only with 2D observation by transmission electron microscopy (TEM) or scanning TEM (STEM). However, the 3D shape and structure of GEMS grains and the spatial distribution of Fe/FeS's has critical information about their formation and origin. Recently, the 3D structure of GEMS grains in ultrathin sections of cluster IDPs was revealed by electron tomography using a TEM/STEM (JEM-2100F, JEOL). However, CT images of thin sections mounted on Cu grids acquired by conventional TEM-tomography are limited to low tilt angles (e. g., less than absolute value of 75 deg. In fact, previous 3D TEM observations of GEMS were affected by some artifacts related to the limited tilt range in the TEM used. Complete tomographic images should be acquired by rotating the sample tilt angle over a range of more than absolute value of 80 deg otherwise the CT images lose their correct structures. In order to constrain the origin and formation process of GEMS grains more clearly, we performed complete electron tomography for GEMS grains. Here we report the sample preparation method we have developed for this study, and the preliminary results.

  1. Molecular detection of Borrelia burgdorferi sensu lato - An analytical comparison of real-time PCR protocols from five different Scandinavian laboratories.

    PubMed

    Lager, Malin; Faller, Maximilian; Wilhelmsson, Peter; Kjelland, Vivian; Andreassen, Åshild; Dargis, Rimtas; Quarsten, Hanne; Dessau, Ram; Fingerle, Volker; Margos, Gabriele; Noraas, Sølvi; Ornstein, Katharina; Petersson, Ann-Cathrine; Matussek, Andreas; Lindgren, Per-Eric; Henningsson, Anna J

    2017-01-01

    Lyme borreliosis (LB) is the most common tick transmitted disease in Europe. The diagnosis of LB today is based on the patient´s medical history, clinical presentation and laboratory findings. The laboratory diagnostics are mainly based on antibody detection, but in certain conditions molecular detection by polymerase chain reaction (PCR) may serve as a complement. The purpose of this study was to evaluate the analytical sensitivity, analytical specificity and concordance of eight different real-time PCR methods at five laboratories in Sweden, Norway and Denmark. Each participating laboratory was asked to analyse three different sets of samples (reference panels; all blinded) i) cDNA extracted and transcribed from water spiked with cultured Borrelia strains, ii) cerebrospinal fluid spiked with cultured Borrelia strains, and iii) DNA dilution series extracted from cultured Borrelia and relapsing fever strains. The results and the method descriptions of each laboratory were systematically evaluated. The analytical sensitivities and the concordance between the eight protocols were in general high. The concordance was especially high between the protocols using 16S rRNA as the target gene, however, this concordance was mainly related to cDNA as the type of template. When comparing cDNA and DNA as the type of template the analytical sensitivity was in general higher for the protocols using DNA as template regardless of the use of target gene. The analytical specificity for all eight protocols was high. However, some protocols were not able to detect Borrelia spielmanii, Borrelia lusitaniae or Borrelia japonica.

  2. Comparison of analytical and semi-preparative columns for high-performance liquid chromatography-solid-phase extraction-nuclear magnetic resonance.

    PubMed

    Miliauskas, Giedrius; van Beek, Teris A; de Waard, Pieter; Venskutonis, Rimantas P; Sudhölter, Ernst J R

    2006-04-21

    The application of analytical and semi-preparative columns in reversed-phase liquid chromatography-solid-phase extraction-nuclear magnetic resonance (HPLC-SPE-NMR) was compared. The work was aiming at separating a higher sample amount in a single run and in this way to reduce the necessary NMR measurement time of separated compounds. Several parameters for compound separation and trapping procedures were optimised: flow rate of HPLC and make-up water pumps, choice of stationary phase cartridges and drying time. The separation and loadability of nine model compounds on analytical and semi-preparative columns was determined, as well as the focussing capacity of SH-type SPE cartridges. It was found that a semi-preparative column--or multiple peak trapping on analytical columns--gave better results than a standard 4.6mm analytical column for non-polar compounds (e.g. flavonoid aglycones, sesquiterpene lactones, non-polar terpenes, logP>2), but for polar compounds (logP<-2) did not offer any advantage over an analytical column, or was even disadvantageous. For intermediately polar compounds (-2

  3. Investigating materials formation with liquid-phase and cryogenic TEM

    NASA Astrophysics Data System (ADS)

    de Yoreo, J. J.; N. A. J. M., Sommerdijk

    2016-08-01

    The recent advent of liquid-phase transmission electron microscopy (TEM) and advances in cryogenic TEM are transforming our understanding of the physical and chemical mechanisms underlying the formation of materials in synthetic, biological and geochemical systems. These techniques have been applied to study the dynamic processes of nucleation, self-assembly, crystal growth and coarsening for metallic and semiconductor nanoparticles, (bio)minerals, electrochemical systems, macromolecular complexes, and organic and inorganic self-assembling systems. New instrumentation and methodologies that are currently on the horizon promise new opportunities for advancing the science of materials synthesis.

  4. 'How I do it': TEM for tumors of the rectum.

    PubMed

    Collinson, Rowan J; McC Mortensen, Neil J

    2009-02-01

    Transanal endoscopic microsurgery (TEM) has an established role in the management of benign rectal tumors. It also has an expanding role in the management of malignant tumors, which is more demanding for the clinician. It requires accurate histological and radiological assessment and draws on an expert understanding of the nature of local recurrence, metastasis, and the place of adjuvant therapies. A multidisciplinary approach is recommended. This paper discusses our institutional approach to TEM for benign and malignant tumors and covers some of the current management controversies.

  5. Below-Band-Gap Laser Ablation Of Diamond For TEM

    NASA Technical Reports Server (NTRS)

    George, Thomas; Foote, Marc C.; Vasquez, Richard P.; Fortier, Edward P.; Posthill, John B.

    1995-01-01

    Thin, electron-transparent layers of diamond for examination in transmission electron microscope (TEM) fabricated from thicker diamond substrates by using laser beam to ablate surface of substrate. Involves use of photon energy below band gap. Growing interest in use of diamond as bulk substrate and as coating material in variety of applications has given rise to increasing need for TEM for characterization of diamond-based materials. Below-band-gap laser ablation method helps to satisfy this need. Also applied in general to cutting and etching of diamonds.

  6. TEM derivative-producing Enterobacter aerogenes strains: dissemination of a prevalent clone.

    PubMed

    Dumarche, P; De Champs, C; Sirot, D; Chanal, C; Bonnet, R; Sirot, J

    2002-04-01

    TEM-24 (CAZ-6) extended-spectrum beta-lactamase (ESBL) was detected in 1988 in Clermont-Ferrand, France, in Klebsiella pneumoniae (bla(TEM-24)) and Enterobacter aerogenes (bla(TEM-24b)), and since 1994, a TEM-24-producing E. aerogenes clonal strain has been observed elsewhere in the country. To determine if the spread of this clonal strain was restricted to TEM-24-producing E. aerogenes strains, 84 E. aerogenes strains (non-TEM/SHV-producing strains, TEM-1- or -2-producing strains, and different ESBL-producing strains), isolated from 1988 to 1999 in Clermont-Ferrand (n = 59) and in 11 other French hospitals in 1998 (n = 25), were studied. A clonal strain was found for TEM-24- but also for TEM-3- and TEM-1- or 2-producing isolates. This study shows that there is a clonal strain dependent on acquisition of the TEM-type enzyme (TEM-24 and other TEM types).

  7. Lidar returns from multiply scattering media in multiple-field-of-view and CCD lidars with polarization devices: comparison of semi-analytical solution and Monte Carlo data.

    PubMed

    Chaikovskaya, Ludmila I; Zege, Eleonora P; Katsev, Iosif L; Hirschberger, Markus; Oppel, Ulrich G

    2009-01-20

    Quite recently, a semi-analytical approach to the sounding of multiply scattering media (clouds, seawaters) using multiple-field-of-view and CCD lidars with polarization devices was developed. The angular distributions of polarized components of the lidar returns from multiply scattering media computed on the basis of this theory using the small-angle approximation are presented and discussed. The semi-analytical nature of the solution makes the computation procedure faster. The obtained data are compared with results provided by the most advanced Monte Carlo algorithms for simulation of modern lidar performance. The good agreement between data provided by the semi-analytical approach and Monte Carlo computations assures one that these approaches can serve as a reliable theoretical base for interpretation and inversion of cloud lidar sounding data obtained with polarized lidars, including polarized multiple-field-of-view and CCD lidars.

  8. A reference interval study for common biochemical analytes in Eastern Turkey: a comparison of a reference population with laboratory data mining

    PubMed Central

    Bakan, Ebubekir; Polat, Harun; Ozarda, Yesim; Ozturk, Nurinnisa; Baygutalp, Nurcan Kilic; Umudum, Fatma Zuhal; Bakan, Nuri

    2016-01-01

    Introduction The aim of this study was to define the reference intervals (RIs) in a Turkish population living in Northeast Turkey (Erzurum) for 34 analytes using direct and indirect methods. In the present study, the regional RIs obtained were compared with other RI studies, primarily the nationwide study performed in Turkey. Materials and methods For the direct method, 435 blood samples were collected from a healthy group of females (N = 218) and males (N = 217) aged between 18 and 65 years. The sera were analysed in Ataturk University hospital laboratory using Roche reagents and analysers for 34 analytes. The data from 1,366,948 records were used to calculate the indirect RIs using a modified Bhattacharya method. Results Significant gender-related differences were observed for 17 analytes. There were also some apparent differences between RIs derived from indirect and direct methods particularly in some analytes (e.g. gamma-glutamyltransferase, creatine kinase, LDL-cholesterol and iron). The RIs derived with the direct method for some, but not all, of the analytes were generally comparable with the RIs reported in the nationwide study and other previous studies in Turkey.There were large differences between RIs derived by the direct method and the expected values shown in the kit insert (e.g. aspartate aminotransferase, total-cholesterol, HDL-cholesterol, and vitamin B12). Conclusions These data provide region-specific RIs for 34 analytes determined by the direct and indirect methods. The observed differences in RIs between previous studies could be related to nutritional status and environmental factors. PMID:27346966

  9. A reference interval study for common biochemical analytes in Eastern Turkey: a comparison of a reference population with laboratory data mining.

    PubMed

    Bakan, Ebubekir; Polat, Harun; Ozarda, Yesim; Ozturk, Nurinnisa; Baygutalp, Nurcan Kilic; Umudum, Fatma Zuhal; Bakan, Nuri

    2016-01-01

    The aim of this study was to define the reference intervals (RIs) in a Turkish population living in Northeast Turkey (Erzurum) for 34 analytes using direct and indirect methods. In the present study, the regional RIs obtained were compared with other RI studies, primarily the nationwide study performed in Turkey. For the direct method, 435 blood samples were collected from a healthy group of females (N = 218) and males (N = 217) aged between 18 and 65 years. The sera were analysed in Ataturk University hospital laboratory using Roche reagents and analysers for 34 analytes. The data from 1,366,948 records were used to calculate the indirect RIs using a modified Bhattacharya method. Significant gender-related differences were observed for 17 analytes. There were also some apparent differences between RIs derived from indirect and direct methods particularly in some analytes (e.g. gamma-glutamyltransferase, creatine kinase, LDL-cholesterol and iron). The RIs derived with the direct method for some, but not all, of the analytes were generally comparable with the RIs reported in the nationwide study and other previous studies in Turkey.There were large differences between RIs derived by the direct method and the expected values shown in the kit insert (e.g. aspartate aminotransferase, total-cholesterol, HDL-cholesterol, and vitamin B12). These data provide region-specific RIs for 34 analytes determined by the direct and indirect methods. The observed differences in RIs between previous studies could be related to nutritional status and environmental factors.

  10. A survey of jet aircraft PM by TEM in APEX III

    NASA Astrophysics Data System (ADS)

    Huang, Chung-Hsuan; Bryg, Victoria M.; Vander Wal, Randy L.

    2016-09-01

    Results are reported for sampling non-volatile particulate matter from field tests during the NASA led APEX III campaign. This paper reports observations of particulate emissions collected from a suite of jet engine aircraft to assess differences and similarities in soot macro- micro- and nanostructure using TEM. Aggregates are compact, primary particle sizes varied and nanostructure is mixed. Comparisons are made to soot from a laboratory flame as a well-studied reference. Results are interpreted in terms of turbulence interacting with the different stages of particle formation and growth with implications for atmospheric processing and climate impact.

  11. A Survey of Jet Aircraft PM by TEM in APEX III

    NASA Technical Reports Server (NTRS)

    VanderWal, Randy L.; Bryg, Victoria M.

    2014-01-01

    Based upon field testing during the NASA led APEX III campaign conducted in November 2005 at the NASA Glenn Research Center in coordination with Continental Airlines and Cleveland Hopkins International Airport. This paper reports observations of particulate emissions collected from a suite of jet engine aircraft to assess differences and similarities in soot macro- micro- and nanostructure using transmission electron microscopy (TEM). Aggregates are compact, primary particle sizes varied and nanostructure mixed. Comparisons are made to more familiar laboratory flame-generated soot as a well-studied point of reference. Results are interpreted in terms of turbulence interacting with the different stages of particle formation and growth.

  12. Coarsening of Pd nanoparticles in an oxidizing atmosphere studied by in situ TEM

    NASA Astrophysics Data System (ADS)

    Simonsen, Søren Bredmose; Chorkendorff, Ib; Dahl, Søren; Skoglundh, Magnus; Helveg, Stig

    2016-06-01

    The coarsening of supported palladium nanoparticles in an oxidizing atmosphere was studied in situ by means of transmission electron microscopy (TEM). Specifically, the Pd nanoparticles were dispersed on a planar and amorphous Al2O3 support and were observed during the exposure to 10 mbar technical air at 650 °C. Time-resolved TEM image series reveal that the Pd nanoparticles were immobile and that a few percent of the nanoparticles grew or shrank, indicating a coarsening process mediated by the Ostwald ripening mechanism. The TEM image contrast suggests that the largest nanoparticles tended to wet the Al2O3 support to a higher degree than the smaller nanoparticles and that the distribution of projected particle sizes consequently broadens by the appearance of an asymmetric tail toward the larger particle sizes. A comparison with computer simulations based on a simple mean-field model for the Ostwald ripening process indicates that the observed change in the particle size distribution can be accounted for by wetting of the Al2O3 support by the larger Pd nanoparticles.

  13. RECENT DEVELOPMENT IN TEM CHARACTERIZATION OF IRRADIATED RERTR FUELS

    SciTech Connect

    J. Gan; B.D. Miller; D.D. Keiser Jr.; A.B. Robinson; J.W. Madden; P.G. Medvedev; D.M. Wachs

    2011-10-01

    The recent development on TEM work of irradiated RERTR fuels includes microstructural characterization of the irradiated U-10Mo/alloy-6061 monolithic fuel plate, the RERTR-7 U-7Mo/Al-2Si and U-7Mo/Al-5Si dispersion fuel plates. It is the first time that a TEM sample of an irradiated nuclear fuel was prepared using the focused-ion-beam (FIB) lift-out technical at the Idaho National Laboratory. Multiple FIB TEM samples were prepared from the areas of interest in a SEM sample. The characterization was carried out using a 200kV TEM with a LaB6 filament. The three dimensional orderings of nanometer-sized fission gas bubbles are observed in the crystalline region of the U-Mo fuel. The co-existence of bubble superlattice and dislocations is evident. Detailed microstructural information along with composition analysis is obtained. The results and their implication on the performance of these fuels are discussed.

  14. Dopant profiling in the TEM, progress towards quantitative electron holography

    SciTech Connect

    Cooper, David; Truche, Robert; Chabli, Amal; Twitchett-Harrison, Alison C.; Midgley, Paul A.; Dunin-Borkowski, Rafal E.

    2007-09-26

    Off-axis electron holography has been used to characterise the dopant potential in GaAs p-n junctions. We show that the measured potential across the junctions is affected by both FIB specimen preparation and by charging in the TEM and suggest methods that can be used to minimise these problems.

  15. Comparison of methods for measurement of organic compounds at ultra-trace level: analytical criteria and application to analysis of amino acids in extraterrestrial samples.

    PubMed

    Vandenabeele-Trambouze, O; Claeys-Bruno, M; Dobrijevic, M; Rodier, C; Borruat, G; Commeyras, A; Garrelly, L

    2005-02-01

    The need for criteria to compare different analytical methods for measuring extraterrestrial organic matter at ultra-trace levels in relatively small and unique samples (e.g., fragments of meteorites, micrometeorites, planetary samples) is discussed. We emphasize the need to standardize the description of future analyses, and take the first step toward a proposed international laboratory network for performance testing.

  16. Comparisons of Mathematics Achievement, Attitude towards Mathematics and Analytical Thinking between Using the Geometer's Sketchpad Program as Media and Conventional Learning Activities

    ERIC Educational Resources Information Center

    Phonguttha, Renuwat; Tayraukham, Sombat; Nuangchalerm, Prasart

    2009-01-01

    This study aimed to compare mathematics learning achievement entitled Parabola, attitude towards mathematics, and analytical thinking abilities of Mathayomsuksa 3 (grade 9) students between organization of activities using the Geometer's Sketchpad Program as media and organization of activities using conventional method. They were assigned into an…

  17. The “2T” ion-electron semi-analytic shock solution for code-comparison with xRAGE: A report for FY16

    SciTech Connect

    Ferguson, Jim Michael

    2016-10-05

    This report documents an effort to generate the semi-analytic "2T" ion-electron shock solution developed in the paper by Masser, Wohlbier, and Lowrie, and the initial attempts to understand how to use this solution as a code-verification tool for one of LANL's ASC codes, xRAGE. Most of the work so far has gone into generating the semi-analytic solution. Considerable effort will go into understanding how to write the xRAGE input deck that both matches the boundary conditions imposed by the solution, and also what physics models must be implemented within the semi-analytic solution itself to match the model assumptions inherit within xRAGE. Therefore, most of this report focuses on deriving the equations for the semi-analytic 1D-planar time-independent "2T" ion-electron shock solution, and is written in a style that is intended to provide clear guidance for anyone writing their own solver.

  18. Ab initio analytical Raman intensities for periodic systems through a coupled perturbed Hartree-Fock/Kohn-Sham method in an atomic orbital basis. II. Validation and comparison with experiments

    NASA Astrophysics Data System (ADS)

    Maschio, Lorenzo; Kirtman, Bernard; Rérat, Michel; Orlando, Roberto; Dovesi, Roberto

    2013-10-01

    In this work, we validate a new, fully analytical method for calculating Raman intensities of periodic systems, developed and presented in Paper I [L. Maschio, B. Kirtman, M. Rérat, R. Orlando, and R. Dovesi, J. Chem. Phys. 139, 164101 (2013)]. Our validation of this method and its implementation in the CRYSTAL code is done through several internal checks as well as comparison with experiment. The internal checks include consistency of results when increasing the number of periodic directions (from 0D to 1D, 2D, 3D), comparison with numerical differentiation, and a test of the sum rule for derivatives of the polarizability tensor. The choice of basis set as well as the Hamiltonian is also studied. Simulated Raman spectra of α-quartz and of the UiO-66 Metal-Organic Framework are compared with the experimental data.

  19. Ab initio analytical Raman intensities for periodic systems through a coupled perturbed Hartree-Fock/Kohn-Sham method in an atomic orbital basis. II. Validation and comparison with experiments.

    PubMed

    Maschio, Lorenzo; Kirtman, Bernard; Rérat, Michel; Orlando, Roberto; Dovesi, Roberto

    2013-10-28

    In this work, we validate a new, fully analytical method for calculating Raman intensities of periodic systems, developed and presented in Paper I [L. Maschio, B. Kirtman, M. Rérat, R. Orlando, and R. Dovesi, J. Chem. Phys. 139, 164101 (2013)]. Our validation of this method and its implementation in the CRYSTAL code is done through several internal checks as well as comparison with experiment. The internal checks include consistency of results when increasing the number of periodic directions (from 0D to 1D, 2D, 3D), comparison with numerical differentiation, and a test of the sum rule for derivatives of the polarizability tensor. The choice of basis set as well as the Hamiltonian is also studied. Simulated Raman spectra of α-quartz and of the UiO-66 Metal-Organic Framework are compared with the experimental data.

  20. In situ TEM studies of carbon and gold nanostructures

    NASA Astrophysics Data System (ADS)

    Casillas Garcia, Gilberto

    Properties of matter change as structures go down in size to the nanoscale, creating new possibilities for creating new functional materials with better properties than the bulk. In situ TEM techniques were used to probe the properties of two different materials: atomic carbon chains and gold nanoparticles. Carbon chains were synthesized by in situ TEM electron beam irradiation from few-layers-graphene (FLG) flakes. Several chains up to 5 nm long were observed. Aberration corrected TEM confirmed the dimerization of the linear chain as predicted by Peierls. Moreover, it was observed that two linear carbon chains can cross-bond every 9 atoms, and it was confirmed by DFT calculations. Five-fold nanoparticles are not supposed to be stable beyond 5 nm size. Here, decahedra with high index facets in the order of 300 nm were studied by TEM. It was found that the high index facets were only stable by adding a capping agent, otherwise, smooth edges were observed. In this case, a (5x1) hexagonal surface reconstruction was observed on the {001} surfaces, with the hexagonal strings along a [110] and a [410] direction. Additionally, mechanical properties of gold nanoparticles, with and without twin boundaries, under 100 nm were measured by in situ TEM compression experiments. All of the nanoparticles presented yield strengths in the order of GPa. Multi twinned nanoparticles were found to be more malleable, reaching real compressing strains of 100 %, while the single crystal nanoparticle presented less plastic flow. Molecular dynamics simulations revealed that the twin boundaries contribute to the malleability of the nanoparticles, at the same time it provides a mechanism to stop dislocations, hence, strain hardening the nanoparticle at later stages of compression. Finally, the behavior of a single grain boundary was studied by in situ TEM manipulation of nanoparticles. A liquid-like behavior of a grain boundary is observed after two 40 nm gold nanoparticles are brought to

  1. TEM sample preparation by femtosecond laser machining and ion milling for high-rate TEM straining experiments.

    PubMed

    Voisin, Thomas; Grapes, Michael D; Zhang, Yong; Lorenzo, Nicholas; Ligda, Jonathan; Schuster, Brian; Weihs, Timothy P

    2016-12-05

    To model mechanical properties of metals at high strain rates, it is important to visualize and understand their deformation at the nanoscale. Unlike post mortem Transmission Electron Microscopy (TEM), which allows one to analyze defects within samples before or after deformation, in situ TEM is a powerful tool that enables imaging and recording of deformation and the associated defect motion during mechanical loading. Unfortunately, all current in situ TEM mechanical testing techniques are limited to quasi-static strain rates. In this context, we are developing a new test technique that utilizes a rapid straining stage and the Dynamic TEM (DTEM) at the Lawrence Livermore National Laboratory (LLNL). The new straining stage can load samples in tension at strain rates as high as 4×10(3)/s using two piezoelectric actuators operating in bending while the DTEM at LLNL can image in movie mode with a time resolution as short as 70ns. Given the piezoelectric actuators are limited in force, speed, and displacement, we have developed a method for fabricating TEM samples with small cross-sectional areas to increase the applied stresses and short gage lengths to raise the applied strain rates and to limit the areas of deformation. In this paper, we present our effort to fabricate such samples from bulk materials. The new sample preparation procedure combines femtosecond laser machining and ion milling to obtain 300µm wide samples with control of both the size and location of the electron transparent area, as well as the gage cross-section and length.

  2. An Analytical Comparison of the Fidelity of "Large Motion" Versus "Small Motion" Flight Simulators in a Rotorcraft Side-Step Task

    NASA Technical Reports Server (NTRS)

    Hess, Ronald A.

    1999-01-01

    This paper presents an analytical and experimental methodology for studying flight simulator fidelity. The task was a rotorcraft bob-up/down maneuver in which vertical acceleration constituted the motion cue. The task considered here is aside-step maneuver that differs from the bob-up one important way: both roll and lateral acceleration cues are available to the pilot. It has been communicated to the author that in some Verticle Motion Simulator (VMS) studies, the lateral acceleration cue has been found to be the most important. It is of some interest to hypothesize how this motion cue associated with "outer-loop" lateral translation fits into the modeling procedure where only "inner-loop " motion cues were considered. This Note is an attempt at formulating such an hypothesis and analytically comparing a large-motion simulator, e.g., the VMS, with a small-motion simulator, e.g., a hexapod.

  3. Comparison of Electron Transmittance and Tunneling Current through a Trapezoidal Potential Barrier with Spin Polarization Consideration by using Analytical and Numerical Approaches

    NASA Astrophysics Data System (ADS)

    Nabila, Ezra; Noor, Fatimah A.; Khairurrijal

    2017-07-01

    In this study, we report an analytical calculation of electron transmittance and polarized tunneling current in a single barrier heterostructure of a metal-GaSb-metal by considering the Dresselhaus spin orbit effect. Exponential function, WKB method and Airy function were used in calculating the electron transmittance and tunneling current. A Transfer Matrix Method, as a numerical method, was utilized as the benchmark to evaluate the analytical calculation. It was found that the transmittances calculated under exponential function and Airy function is the same as that calculated under TMM method at low electron energy. However, at high electron energy only the transmittance calculated under Airy function approach is the same as that calculated under TMM method. It was also shown that the transmittances both of spin-up and spin-down conditions increase as the electron energy increases for low energies. Furthermore, the tunneling current decreases with increasing the barrier width.

  4. An inter-laboratory comparison of different analytical methods for the determination of monomethylmercury in various soil and sediment samples: A platform for method improvement.

    PubMed

    Kodamatani, Hitoshi; Balogh, Steven J; Nollet, Yabing H; Matsuyama, Akito; Fajon, Vesna; Horvat, Milena; Tomiyasu, Takashi

    2017-02-01

    An inter-laboratory study was conducted to compare results from different analytical methods for monomethylmercury (MeHg) concentrations in 17 soil and sediment samples. The samples were collected from mercury-contaminated areas, including Minamata Bay and Kagoshima Bay in Japan, the Idrija mercury mine in Slovenia, and an artisanal small-scale gold mining area in Indonesia. The Hg in these samples comes from several different sources: industrial waste from an acetaldehyde production facility, volcanic activity, Hg mining activity, and artisanal and small-scale gold mining activity (ASGM). MeHg concentrations in all the samples were measured in four separate laboratories, using three different determination methods: Kagoshima University (Japan), using high-performance liquid chromatography-chemiluminescence detection (HPLC-CL); National Institute for Minamata Disease (Japan), using gas chromatography-electron capture detection; and Metropolitan Council Environmental Services (USA) and Jozef Stefan Institute (Slovenia), both using alkylation-gas chromatography-atomic fluorescence spectrometry detection. The methods gave comparable MeHg results for most of the samples tested, but for some samples, the results exhibited significant variability depending on the method used. The HPLC-CL method performed poorly when applied to samples with elevated sulfur concentrations, producing MeHg concentrations that were much lower than those from the other methods. Additional analytical work demonstrated the elimination of this sulfur interference when the method was modified to bind sulfur prior to the analytical step by using Hg(2+) as a masking agent. These results demonstrate the value of laboratory intercomparison exercises in contributing to the improvement of analytical methods.

  5. A comparison of 1D analytical model and 3D finite element analysis with experiments for a rosen-type piezoelectric transformer.

    PubMed

    Boukazouha, F; Poulin-Vittrant, G; Tran-Huu-Hue, L P; Bavencoffe, M; Boubenider, F; Rguiti, M; Lethiecq, M

    2015-07-01

    This article is dedicated to the study of Piezoelectric Transformers (PTs), which offer promising solutions to the increasing need for integrated power electronics modules within autonomous systems. The advantages offered by such transformers include: immunity to electromagnetic disturbances; ease of miniaturisation for example, using conventional micro fabrication processes; and enhanced performance in terms of voltage gain and power efficiency. Central to the adequate description of such transformers is the need for complex analytical modeling tools, especially if one is attempting to include combined contributions due to (i) mechanical phenomena owing to the different propagation modes which differ at the primary and secondary sides of the PT; and (ii) electrical phenomena such as the voltage gain and power efficiency, which depend on the electrical load. The present work demonstrates an original one-dimensional (1D) analytical model, dedicated to a Rosen-type PT and simulation results are successively compared against that of a three-dimensional (3D) Finite Element Analysis (COMSOL Multiphysics software) and experimental results. The Rosen-type PT studied here is based on a single layer soft PZT (P191) with corresponding dimensions 18 mm × 3 mm × 1.5 mm, which operated at the second harmonic of 176 kHz. Detailed simulational and experimental results show that the presented 1D model predicts experimental measurements to within less than 10% error of the voltage gain at the second and third resonance frequency modes. Adjustment of the analytical model parameters is found to decrease errors relative to experimental voltage gain to within 1%, whilst a 2.5% error on the output admittance magnitude at the second resonance mode were obtained. Relying on the unique assumption of one-dimensionality, the present analytical model appears as a useful tool for Rosen-type PT design and behavior understanding. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Requisite analytic and diagnostic performance characteristics for the clinical detection of BRAF V600E in hairy cell leukemia: a comparison of 2 allele-specific PCR assays.

    PubMed

    Brown, Noah A; Weigelin, Helmut C; Bailey, Nathanael; Laliberte, Julie; Elenitoba-Johnson, Kojo S J; Lim, Megan S; Betz, Bryan L

    2015-09-01

    Detection of high-frequency BRAF V600E mutations in hairy cell leukemia (HCL) has important diagnostic utility. However, the requisite analytic performance for a clinical assay to routinely detect BRAF V600E mutations in HCL has not been clearly defined. In this study, we sought to determine the level of analytic sensitivity needed for formalin-fixed, paraffin-embedded (FFPE) and frozen samples and to compare the performance of 2 allele-specific polymerase chain reaction (PCR) assays. Twenty-nine cases of classic HCL, including 22 FFPE bone marrow aspirates and 7 frozen specimens from blood or bone marrow were evaluated using a laboratory-developed allele-specific PCR assay and a commercially available allele-specific quantitative PCR assay-myT BRAF Ultra. Also included were 6 HCL variant and 40 non-HCL B-cell lymphomas. Two cases of classic HCL, 1 showing CD5 expression, were truly BRAF V600E-negative based on negative results by PCR and sequencing despite high-level leukemic involvement. Among the remaining 27 specimens, V600E mutations were detected in 88.9% (17/20 FFPE; 7/7 frozen) and 81.5% (15/20 FFPE; 7/7 frozen), for the laboratory-developed and commercial assays, respectively. No mutations were detected among the 46 non-HCL lymphomas. Both assays showed an analytic sensitivity of 0.3% involvement in frozen specimens and 5% in FFPE tissue. On the basis of these results, an assay with high analytic sensitivity is required for the clinical detection of V600E mutations in HCL specimens. Two allele-specific PCR assays performed well in both frozen and FFPE bone marrow aspirates, although detection in FFPE tissue required 5% or more involvement.

  7. [Comparison of two new plastic tubes (Sekisui INSEPACK and Green Cross Green Vac-Tube) with BD Vacutainer tubes for 49 analytes].

    PubMed

    Oh, Sue-Hyun; Ki, Chang-Seok

    2007-02-01

    Becton Dickinson (BD) Vacutainer tubes are the most widely used vacuum system for collection of blood in clinical laboratories. We compared the performance of two new tubes, Sekisui INSEPACK tube and Green Cross Green Vac-Tube, with the existing BD Vacutainer tubes for 49 common analytes. A total of 20 apparently healthy volunteers were recruited for this study. For rountine chemistry and thyroid function tests, we compared the results of two new vacutainer tubes and BD Vacutainer tubes with those of BD glass tubes at t=0 hr by student paired t test. Hematology and coagulation test results of the two new vacutainer tubes were compared with those of BD Vacutainer tubes at t=0 hr. To study the stability of each analyte, results at t=24 +/- 2 hr, t=72 +/- 2 hr, and t=168 +/- 2 hr were compared with those at t=0 hr for each tube. Although paired t test analysis revealed statistically significant differences between two tested tubes and existing BD Vacutainer tube in several tests (total protein, total bilirubin, alkaline phosphatase, glucose, uric acid, calcium, inorganic phosphorus, direct bilirubin, triglyceride, HDL-cholesterol, LDL-cholesterol, lactate dehydrogenase, triiodothyronine, and thyroxine), these differences were not considered clinically significant. Stability of two new vacuum tubes for each analyte was similar to that of the BD Vacutainer tube. Sekisui INSEPACK tube and Green Cross Green-Vac Tube showed a satisfactory analytical performance compared with existing BD Vacutainer tubes. We conclude that these two new plastic vacutainer tubes are acceptable for the commonly ordered laboratory tests.

  8. On the energy dependence of the radial diffusion coefficient and spectra of inner radiation belt particles - Analytic solutions and comparison with numerical results

    NASA Technical Reports Server (NTRS)

    Westphalen, H.; Spjeldvik, W. N.

    1982-01-01

    A theoretical method by which the energy dependence of the radial diffusion coefficient may be deduced from spectral observations of the particle population at the inner edge of the earth's radiation belts is presented. This region has previously been analyzed with numerical techniques; in this report an analytical treatment that illustrates characteristic limiting cases in the L shell range where the time scale of Coulomb losses is substantially shorter than that of radial diffusion (L approximately 1-2) is given. It is demonstrated both analytically and numerically that the particle spectra there are shaped by the energy dependence of the radial diffusion coefficient regardless of the spectral shapes of the particle populations diffusing inward from the outer radiation zone, so that from observed spectra the energy dependence of the diffusion coefficient can be determined. To insure realistic simulations, inner zone data obtained from experiments on the DIAL, AZUR, and ESRO 2 spacecraft have been used as boundary conditions. Excellent agreement between analytic and numerical results is reported.

  9. On the energy dependence of the radial diffusion coefficient and spectra of inner radiation belt particles - Analytic solutions and comparison with numerical results

    NASA Technical Reports Server (NTRS)

    Westphalen, H.; Spjeldvik, W. N.

    1982-01-01

    A theoretical method by which the energy dependence of the radial diffusion coefficient may be deduced from spectral observations of the particle population at the inner edge of the earth's radiation belts is presented. This region has previously been analyzed with numerical techniques; in this report an analytical treatment that illustrates characteristic limiting cases in the L shell range where the time scale of Coulomb losses is substantially shorter than that of radial diffusion (L approximately 1-2) is given. It is demonstrated both analytically and numerically that the particle spectra there are shaped by the energy dependence of the radial diffusion coefficient regardless of the spectral shapes of the particle populations diffusing inward from the outer radiation zone, so that from observed spectra the energy dependence of the diffusion coefficient can be determined. To insure realistic simulations, inner zone data obtained from experiments on the DIAL, AZUR, and ESRO 2 spacecraft have been used as boundary conditions. Excellent agreement between analytic and numerical results is reported.

  10. MT3FT-15OR0204122: Report on the acquisition and installation of FEI Talos F200X S/TEM

    SciTech Connect

    Parish, Chad M.

    2015-09-01

    This document describes the installation, performance, and early results from the FCRD-funded acquisition of a new advanced analytical scanning / transmission electron microscopy (S/TEM) at the Oak Ridge National Laboratory Low Activation Materials Development and Analysis (LAMDA) facility.

  11. Effects of diagnostic ionizing radiation on pregnancy via TEM

    NASA Astrophysics Data System (ADS)

    Mohammed, W. H.; Artoli, A. M.

    2008-08-01

    In Sudan, X-rays are routinely used at least once for measurements of pelvis during the gestation period, though this is highly prohibited worldwide, except for a few life threatening cases. To demonstrate the effect of diagnostic ionizing radiation on uterus, fetus and neighboring tissues to the ovaries, two independent experiments on pregnant rabbits were conducted. The first experiment was a proof of concept that diagnostic ionizing radiation is hazardous throughout the gestation period. The second experiment was done through Transmission Electron Microscopy (TEM) to elucidate the morphological changes in the ultra structure of samples taken from irradiated pregnant rabbits. This study uses TEM to test the effect of diagnostic radiation of less than 0.6 Gray on the cellular level. Morphological changes have been captured and the images were analyzed to quantify these effects.

  12. High Spatial Resolution Study of Microbe-Carbonate-Silicate Interfaces by FIB and TEM

    NASA Astrophysics Data System (ADS)

    Benzerara, K.; Menguy, N.; Guyot, F.; Vanni, C.; Gillet, P.

    2003-12-01

    High resolution transmission electron microscopy (HRTEM), chemical micro-analysis (EDX) and electron energy loss spectroscopy (EELS) are among the most powerful analytical techniques for studying microbe-mineral interactions, allowing to observe the microbe-mineral interface at almost the angstrom scale, to evidence transformations of the mineral structure and chemical alterations at the nanometer scale. However, the samples must be very thin and only a small area can be investigated. A key limitation for using this technique is thus to prepare natural geomicrobiological samples which combine hard minerals, preventing use of ultramicrotomy, with soft organic matter inadequate to ion milling procedures. Additionaly the areas of interest are usually restricted to few micrometer large areas which have to be selected from macroscopic samples. In this study we present two procedures : micromanipulation and FIB (Focused Ion Beam) which allow the study of microbe-mineral interfaces with TEM. The micromanipulation procedure has been presented in Benzerara et al (2003, PNAS). We have evidenced nannobacteria-like objects at the surface of the Tatahouine orthopyroxenite meteorite fallen in the tunisian desert in 1931. SEM observations suggest a complex interaction pattern between the nannobacteria-like objects, the pyroxene and microorganisms which have colonized the surface of the meteorite during its seventy years of residence on Earth. The TEM study on the very same area shows that the nannobacteria-like rods are actually well-crystallized nanometric calcite single crystals surrounded by an amorphous layer of carbonate composition. Those morphologies and structures are unusual for calcite single crystals. We discuss these observations in regard to the criteria of biogenicity i.e. biosignatures. Moreover, we examine the implications for carbonate production associated to silicate bio-weathering under aridic conditions. This work is relevant both to astrobiological and

  13. Comparing Time Domain Electromagnetics (TEM) and Early-Time TEM for Mapping Highly Conductive Groundwater in Mars Analog Environments

    NASA Astrophysics Data System (ADS)

    Jernsletten, J. A.

    2005-05-01

    Introduction: The purpose of this study is to evaluate the use of (diffusive) Time Domain Electromagnetics (TEM) for sounding of subsurface water in conductive Mars analog environments. To provide a baseline for such studies, I show data from two field studies: 1) Diffusive sounding data (TEM) from Pima County, Arizona; and 2) Shallower sounding data using the Fast-Turnoff TEM method from Peña de Hierro in the Rio Tinto region of Spain. The latter is data from work conducted under the auspices of the Mars Analog Research and Technology Experiment (MARTE). Pima County TEM Survey: A TEM survey was carried out in Pima County, Arizona, in January 2003. Data was collected using 100 m Tx loops and a ferrite-cored magnetic coil Rx antenna, and processed using commercial software. The survey used a 16 Hz sounding frequency, which is sensitive to slightly salty groundwater. Prominent features in the data from Arizona are the ~500 m depth of investigation and the ~120 m depth to the water table, confirmed by data from four USGS test wells surrounding the field area. Note also the conductive (~20-40 ω m) clay-rich soil above the water table. Rio Tinto Fast-Turnoff TEM Survey: During May and June of 2003, a Fast-Turnoff (early time) TEM survey was carried out at the Peña de Hierro field area of the MARTE project, near the town of Nerva, Spain. Data was collected using 20 m and 40 m Tx loop antennae and 10 m loop Rx antennae, with a 32 Hz sounding frequency. Data from Line 4 (of 16) from this survey, collected using 40 m Tx loops, show ~200 m depth of investigation and a conductive high at ~90 m depth below Station 20 (second station of 10 along this line). This is the water table, matching the 431 m MSL elevation of the nearby pit lake. The center of the "pileup" below Station 60 is spatially coincident with the vertical fault plane located here. Data from Line 15 and Line 14 of the Rio Tinto survey, collected using 20 m Tx loops, achieve ~50 m depth of investigation and

  14. SimulaTEM: multislice simulations for general objects.

    PubMed

    Gómez-Rodríguez, A; Beltrán-Del-Río, L M; Herrera-Becerra, R

    2010-01-01

    In this work we present the program SimulaTEM for the simulation of high resolution micrographs and diffraction patterns. This is a program based on the multislice approach that does not assume a periodic object. It can calculate images from finite objects, from amorphous samples, from crystals, quasicrystals, grain boundaries, nanoparticles or arbitrary objects provided the coordinates of all the atoms can be supplied. Copyright 2009 Elsevier B.V. All rights reserved.

  15. Strain mapping in TEM using precession electron diffraction

    DOEpatents

    Taheri, Mitra Lenore; Leff, Asher Calvin

    2017-02-14

    A sample material is scanned with a transmission electron microscope (TEM) over multiple steps having a predetermined size at a predetermined angle. Each scan at a predetermined step and angle is compared to a template, wherein the template is generated from parameters of the material and the scanning. The data is then analyzed using local mis-orientation mapping and/or Nye's tensor analysis to provide information about local strain states.

  16. Characterization of some biological specimens using TEM and SEM

    NASA Astrophysics Data System (ADS)

    Ghosh, Nabarun; Smith, Don W.

    2009-05-01

    The advent of novel techniques using the Transmission and Scanning Electron Microscopes improved observation on various biological specimens to characterize them. We studied some biological specimens using Transmission and Scanning Electron Microscopes. We followed negative staining technique with Phosphotungstic acid using bacterial culture of Bacillus subtilis. Negative staining is very convenient technique to view the structural morphology of different samples including bacteria, phage viruses and filaments in a cell. We could observe the bacterial cell wall and flagellum very well when trapped the negative stained biofilm from bacterial culture on a TEM grid. We cut ultra thin sections from the fixed root tips of Pisum sativum (Garden pea). Root tips were pre fixed with osmium tetroxide and post fixed with uranium acetate and placed in the BEEM capsule for block making. The ultrathin sections on the grid under TEM showed the granular chromatin in the nucleus. The protein bodies and large vacuoles with the storage materials were conspicuous. We followed fixation, critical point drying and sputter coating with gold to view the tissues with SEM after placing on stubs. SEM view of the leaf surface of a dangerous weed Tragia hispida showed the surface trichomes. These trichomes when break on touching releases poisonous content causing skin irritation. The cultured tissue from in vitro culture of Albizia lebbeck, a tree revealed the regenerative structures including leaf buds and stomata on the tissue surface. SEM and TEM allow investigating the minute details characteristic morphological features that can be used for classroom teaching.

  17. Observations from TEM Analysis of Swift Creek Samples

    NASA Astrophysics Data System (ADS)

    Harris, J. R.

    2012-12-01

    Samples analyzed by transmission electron microscopy (TEM) from suspended sediments in Swift Creek have unique characteristics compared to other naturally occurring asbestos (NOA) sites across the country. Our first introduction to the uniqueness of the Swift Creek site came about when we analyzed soil sediments by polarized light microscopy (PLM) and found relatively low or nonexistent levels of chrysotile asbestos. Upon submission of these samples for TEM analysis, we found that the samples were literally filled with small chrysotile fibers and bundles. We also notice a high number of dark, rounded particles which were not asbestiform. Out of curiosity, we viewed the surface features of one of these particles using scanning electron microscopy to find compacted chrysotile fibers bundled inside these particles. These particles contained the vast majority of chrysotile in the sample. This finding began our approach to provide more advanced TEM/SEM methods for identifying and characterizing complex arrangements of asbestos from NOA sites. We will present some of our experiences and methods for characterizing these types of particles common to NOA sites.

  18. A straightforward specimen holder modification for remnant magnetic-field measurement in TEM.

    PubMed

    Lau, J W; Schofield, M A; Zhu, Y

    2007-01-01

    We report a simple means to modify an analytic sample holder to perform ambient Hall probe measurements of the sample area inside a transmission electron microscope (TEM). These measurements are important in the case of electron microscopy studies involving magnetic materials. We characterize the magnetic field of the JEOL 2100F-LM, a microscope dedicated in design to perform magnetic imaging, and also of the JEOL 3000F FEG-TEM operated in Lorentz mode. In the case of the 3000F, we measure vertical remnant field about 300 Oe due to the objective lens of the microscope. In the case of the 2100F, design of the objective lens reduces the remnant field to about 4 Oe. We characterize the field along two orthogonal directions, and spatial characteristics of the field profile are made for both microscopes during all stages of specimen entry into the column. In the case of the 2100F, we additionally measure the field conditions as a function of objective lens excitation, which is important for in situ magnetization experiments. Finally, we provide experimental results illustrating the importance of these measurements.

  19. Quantitative Electrochemical Measurements using in situ ec-S/TEM Devices

    SciTech Connect

    Unocic, Raymond R; Sacci, Robert L; Brown, Gilbert M; Veith, Gabriel M; Dudney, Nancy J; More, Karren Leslie; Gardiner, Daniel; Walden II, Franklin S; Damiano, John; Nackashi, David P.

    2014-01-01

    Insight into dynamic electrochemical processes can be obtained with in situ ec-S/TEM, which utilizes microfluidic electrochemical cells to characterize electrochemical processes with S/TEM imaging, diffraction or spectroscopy. The microfluidic electrochemical cell is composed of microfabricated devices with glassy carbon and platinum microband electrodes in a three-electrode cell configuration. To establish the validity of this method for quantitative in situ electrochemistry research, cyclic voltammetry, choronoamperometry and electrochemical impedance spectroscopy were performed using a standard one electron transfer redox couple using a [Fe(CN)6]3-/4- based electrolyte. Established relationships of the electrode geometry and microfluidic conditions were fitted with cyclic voltammetry and chronoamperometic measurements of analyte diffusion coefficients and was found to agree with well-accepted values that are on the order of 10-5 cm2 s-1. Influence of the electron beam on electrochemical measurements was found to be negligible during CV scans where the current profile varied only within a few nA with the electron beam on and off which is well within the hysteresis between multiple CV scans. The combination of experimental results provides a validation that quantitative electrochemistry experiments can be performed with these small-scale microfluidic electrochemical cells provided that accurate geometrical electrode configurations, diffusion boundary layers and microfluidic conditions are accounted for.

  20. Materials science applications of a 120 kV FEG TEM/STEM: Triskaidekaphilia

    SciTech Connect

    Bentley, J.; Fisher, A.T.; Kenik, E.A.; Wang, Z.L.

    1991-01-01

    The introduction by several manufacturers of 200kV transmission electron microscopes (TEM) equipped with field emission guns affords the opportunity to assess their potential impact on materials science by examining applications of similar 100-120kV instruments that have been in use for more than a decade. This summary is based on results from a Philips EM400T/FEG configured as an analytical electron microscope (AEM) with a 6,585 scanning transmission (STEM) unit, EDAX 9100/70 or 9900 energy dispersive X-ray spectroscopy (EDS) systems, and Gatan 607 serial- or 666 parallel-detection electron energy-loss spectrometers (EELS). Examples in four areas that illustrate applications that are impossible or so difficult as to be impracticable with conventional thermionic electron guns are described.

  1. Compositional analysis of multi-element magnetic nanoparticles with a combined NMR and TEM approach

    NASA Astrophysics Data System (ADS)

    Gellesch, Markus; Hammerath, Franziska; Süß, Vicky; Haft, Marcel; Hampel, Silke; Wurmehl, Sabine; Büchner, Bernd

    2017-09-01

    The increasing interest in nanoscale materials goes hand in hand with the challenge to reliably characterize the chemical compositions and structural features of nanosized objects in order to relate those to their physical properties. Despite efforts, the analysis of the chemical composition of individual multi-element nanoparticles remains challenging—from the technical point of view as well as from the point of view of measurement statistics. Here, we demonstrate that zero-field solid-state nuclear magnetic resonance (NMR) complements local, single particle transmission electron microscopy (TEM) studies with information on a large assembly of chemically complex nanoparticles. The combination of both experimental techniques gives information on the local composition and structure and provides an excellent measurement statistic through the corresponding NMR ensemble measurement. This analytical approach is applicable to many kinds of magnetic materials and therefore may prove very versatile in the future research of particulate magnetic nanomaterials.

  2. Comparison of the analytical and clinical performances of Abbott RealTime High Risk HPV, Hybrid Capture 2, and DNA Chip assays in gynecology patients.

    PubMed

    Park, Seungman; Kang, Youjin; Kim, Dong Geun; Kim, Eui-Chong; Park, Sung Sup; Seong, Moon-Woo

    2013-08-01

    The detection of high-risk (HR) HPV in cervical cancer screening is important for early diagnosis of cervical cancer or pre-cancerous lesions. We evaluated the analytical and clinical performances of 3 HR HPV assays in Gynecology patients. A total of 991 specimens were included in this study: 787 specimens for use with a Hybrid Capture 2 (HC2) and 204 specimens for a HPV DNA microarray (DNA Chip). All specimens were tested using an Abbott RealTime High Risk HPV assay (Real-time HR), PGMY PCR, and sequence analysis. Clinical sensitivities for severe abnormal cytology (severe than high-grade squamous intraepithelial lesion) were 81.8% for Real-time HR, 77.3% for HC2, and 66.7% for DNA Chip, and clinical sensitivities for severe abnormal histology (cervical intraepithelial neoplasia grade 2+) were 91.7% for HC2, 87.5% for Real-time HR, and 73.3% for DNA Chip. As compared to results of the sequence analysis, HC2, Real-time HR, and DNA Chip showed concordance rates of 94.3% (115/122), 90.0% (117/130), and 61.5% (16/26), respectively. The HC2 assay and Real-time HR assay showed comparable results to each other in both clinical and analytical performances, while the DNA Chip assay showed poor clinical and analytical performances. The Real-time HR assay can be a good alternative option for HR HPV testing with advantages of allowing full automation and simultaneous genotyping of HR types 16 and 18.

  3. Analytical Comparison of In Vitro-Spiked Human Serum and Plasma for PCR-Based Detection of Aspergillus fumigatus DNA: a Study by the European Aspergillus PCR Initiative

    PubMed Central

    Mengoli, Carlo; Springer, Jan; Bretagne, Stéphane; Cuenca-Estrella, Manuel; Klingspor, Lena; Lagrou, Katrien; Melchers, Willem J. G.; Morton, C. Oliver; Barnes, Rosemary A.; Donnelly, J. Peter; White, P. Lewis

    2015-01-01

    The use of serum or plasma for Aspergillus PCR testing facilitates automated and standardized technology. Recommendations for serum testing are available, and while serum and plasma are regularly considered interchangeable for use in fungal diagnostics, differences in galactomannan enzyme immunoassay (GM-EIA) performance have been reported and are attributed to clot formation. Therefore, it is important to assess plasma PCR testing to determine if previous recommendations for serum are applicable and also to compare analytical performance with that of serum PCR. Molecular methods testing serum and plasma were compared through multicenter distribution of quality control panels, with additional studies to investigate the effect of clot formation and blood fractionation on DNA availability. Analytical sensitivity and time to positivity (TTP) were compared, and a regression analysis was performed to identify variables that enhanced plasma PCR performance. When testing plasma, sample volume, preextraction-to-postextraction volume ratio, PCR volume, duplicate testing, and the use of an internal control for PCR were positively associated with performance. When whole-blood samples were spiked and then fractionated, the analytical sensitivity and TTP were superior when testing plasma. Centrifugation had no effect on DNA availability, whereas the presence of clot material significantly lowered the concentration (P = 0.028). Technically, there are no major differences in the molecular processing of serum and plasma, but the formation of clot material potentially reduces available DNA in serum. During disease, Aspergillus DNA burdens in blood are often at the limits of PCR performance. Using plasma might improve performance while maintaining the methodological simplicity of serum testing. PMID:26085614

  4. Analytical Comparison of In Vitro-Spiked Human Serum and Plasma for PCR-Based Detection of Aspergillus fumigatus DNA: a Study by the European Aspergillus PCR Initiative.

    PubMed

    Loeffler, Juergen; Mengoli, Carlo; Springer, Jan; Bretagne, Stéphane; Cuenca-Estrella, Manuel; Klingspor, Lena; Lagrou, Katrien; Melchers, Willem J G; Morton, C Oliver; Barnes, Rosemary A; Donnelly, J Peter; White, P Lewis

    2015-09-01

    The use of serum or plasma for Aspergillus PCR testing facilitates automated and standardized technology. Recommendations for serum testing are available, and while serum and plasma are regularly considered interchangeable for use in fungal diagnostics, differences in galactomannan enzyme immunoassay (GM-EIA) performance have been reported and are attributed to clot formation. Therefore, it is important to assess plasma PCR testing to determine if previous recommendations for serum are applicable and also to compare analytical performance with that of serum PCR. Molecular methods testing serum and plasma were compared through multicenter distribution of quality control panels, with additional studies to investigate the effect of clot formation and blood fractionation on DNA availability. Analytical sensitivity and time to positivity (TTP) were compared, and a regression analysis was performed to identify variables that enhanced plasma PCR performance. When testing plasma, sample volume, preextraction-to-postextraction volume ratio, PCR volume, duplicate testing, and the use of an internal control for PCR were positively associated with performance. When whole-blood samples were spiked and then fractionated, the analytical sensitivity and TTP were superior when testing plasma. Centrifugation had no effect on DNA availability, whereas the presence of clot material significantly lowered the concentration (P = 0.028). Technically, there are no major differences in the molecular processing of serum and plasma, but the formation of clot material potentially reduces available DNA in serum. During disease, Aspergillus DNA burdens in blood are often at the limits of PCR performance. Using plasma might improve performance while maintaining the methodological simplicity of serum testing.

  5. Comparison of clinical and analytical performance of the Abbott Realtime High Risk HPV test to the performance of hybrid capture 2 in population-based cervical cancer screening.

    PubMed

    Poljak, Mario; Ostrbenk, Anja; Seme, Katja; Ucakar, Veronika; Hillemanns, Peter; Bokal, Eda Vrtacnik; Jancar, Nina; Klavs, Irena

    2011-05-01

    The clinical performance of the Abbott RealTime High Risk HPV (human papillomavirus) test (RealTime) and that of the Hybrid Capture 2 HPV DNA test (hc2) were prospectively compared in the population-based cervical cancer screening setting. In women >30 years old (n = 3,129), the clinical sensitivity of RealTime for detection of cervical intraepithelial neoplasia of grade 2 (CIN2) or worse (38 cases) and its clinical specificity for lesions of less than CIN2 (3,091 controls) were 100% and 93.3%, respectively, and those of hc2 were 97.4% and 91.8%, respectively. A noninferiority score test showed that the clinical specificity (P < 0.0001) and clinical sensitivity (P = 0.011) of RealTime were noninferior to those of hc2 at the recommended thresholds of 98% and 90%. In the total study population (women 20 to 64 years old; n = 4,432; 57 cases, 4,375 controls), the clinical sensitivity and specificity of RealTime were 98.2% and 89.5%, and those of hc2 were 94.7% and 87.7%, respectively. The analytical sensitivity and analytical specificity of RealTime in detecting targeted HPV types evaluated with the largest sample collection to date (4,479 samples) were 94.8% and 99.8%, and those of hc2 were 93.4% and 97.8%, respectively. Excellent analytical agreement between the two assays was obtained (kappa value, 0.84), while the analytical accuracy of RealTime was significantly higher than that of hc2. RealTime demonstrated high intralaboratory reproducibility and interlaboratory agreement with 500 samples retested 61 to 226 days after initial testing in two different laboratories. RealTime can be considered to be a reliable and robust HPV assay clinically comparable to hc2 for the detection of CIN2+ lesions in a population-based cervical cancer screening setting.

  6. Label-free porous silicon immunosensor for broad detection of opiates in a blind clinical study and results comparison to commercial analytical chemistry techniques.

    PubMed

    Bonanno, Lisa M; Kwong, Tai C; DeLouise, Lisa A

    2010-12-01

    In this work, we evaluate for the first time the performance of a label-free porous silicon (PSi) immunosensor assay in a blind clinical study designed to screen authentic patient urine specimens for a broad range of opiates. The PSi opiate immunosensor achieved 96% concordance with liquid chromatography-mass spectrometry/tandem mass spectrometry (LC-MS/MS) results on samples that underwent standard opiate testing (n = 50). In addition, successful detection of a commonly abused opiate, oxycodone, resulted in 100% qualitative agreement between the PSi opiate sensor and LC-MS/MS. In contrast, a commercial broad opiate immunoassay technique (CEDIA) achieved 65% qualitative concordance with LC-MS/MS. Evaluation of important performance attributes including precision, accuracy, and recovery was completed on blank urine specimens spiked with test analytes. Variability of morphine detection as a model opiate target was <9% both within-run and between-day at and above the cutoff limit of 300 ng mL(-1). This study validates the analytical screening capability of label-free PSi opiate immunosensors in authentic patient samples and is the first semiquantitative demonstration of the technology's successful clinical use. These results motivate future development of label-free PSi technology to reduce complexity and cost of diagnostic testing particularly in a point-of-care setting.

  7. Comparison of different cleanup procedures for oil crops based on the development of a trace analytical method for the determination of pyraclostrobin and epoxiconazole.

    PubMed

    Pan, Xinglu; Dong, Fengshou; Xu, Jun; Liu, Xingang; Cheng, Youpu; Chen, Zenglong; Liu, Na; Chen, Xixi; Tao, Yan; Zheng, Yongquan

    2014-12-01

    The effects of different cleanup procedures in removing high-molecular-mass lipids and natural colorants from oil-crop extracts, including dispersive solid-phase extraction, low-temperature precipitation and gel permeation chromatography, were studied. The pigment removal, lipid quantity, and matrix effects of the three cleanup methods were evaluated. Results indicated that the gel permeation chromatography method is the most effective way to compare the dispersive solid-phase extraction and low-temperature precipitation. Pyraclostrobin and epoxiconazole applied extensively in oil-crop production were selected as typical pesticides to study and a trace analytical method was developed by gel permeation chromatography and ultra high performance liquid chromatography with tandem mass spectrometry. Average recoveries of the target pesticides at three levels (10, 50, and 100 μg/kg) were in the range of 74.7-96.8% with relative standard deviation values below 9.2%. The limits of detection did not exceed 0.46 μg/kg, whereas the limits of quantification were below 1.54 μg/kg and much lower than maximum residue limit in all matrices. This study may provide the essential data for optimizing the analytical method of pesticides in oil-crop samples. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. A Label-Free Porous Silicon Immunosensor for Broad Detection of Opiates in a Blind Clinical Study and Result Comparison to Commercial Analytical Chemistry Techniques

    PubMed Central

    Bonanno, Lisa M.; Kwong, Tai C.; DeLouise, Lisa A.

    2010-01-01

    In this work we evaluate for the first time the performance of a label-free porous silicon (PSi) immunosensor assay in a blind clinical study designed to screen authentic patient urine specimens for a broad range of opiates. The PSi opiate immunosensor achieved 96% concordance with liquid chromatography-mass spectrometry/tandem mass spectrometry (LC-MS/MS) results on samples that underwent standard opiate testing (n=50). In addition, successful detection of a commonly abused opiate, oxycodone, resulted in 100% qualitative agreement between the PSi opiate sensor and LC-MS/MS. In contrast, a commercial broad opiate immunoassay technique (CEDIA®) achieved 65% qualitative concordance with LC-MS/MS. Evaluation of important performance attributes including precision, accuracy, and recovery was completed on blank urine specimens spiked with test analytes. Variability of morphine detection as a model opiate target was < 9% both within-run and between-day at and above the cutoff limit of 300 ng ml−1. This study validates the analytical screening capability of label-free PSi opiate immunosensors in authentic patient samples and is the first semi-quantitative demonstration of the technology’s successful clinical use. These results motivate future development of PSi technology to reduce complexity and cost of diagnostic testing particularly in a point-of-care setting. PMID:21062030

  9. Meta-analytic moderators of experimental exposure to media portrayals of women on female appearance satisfaction: Social comparisons as automatic processes.

    PubMed

    Want, Stephen C

    2009-09-01

    Experimental exposure to idealized media portrayals of women is thought to induce social comparisons in female viewers and thereby to be generally detrimental to female viewers' satisfaction with their own appearance. Through meta-analysis, the present paper examines the impact of moderators of this effect, some identified and updated from a prior meta-analysis and some that have hitherto received little attention. Participants' pre-existing appearance concerns and the processing instructions participants were given when exposed to media portrayals were found to significantly moderate effect sizes. With regard to processing instructions, a novel and counter-intuitive pattern was revealed; effect sizes were smallest when participants were instructed to focus on the appearance of women in media portrayals, and largest when participants processed the portrayals on a distracting, non-appearance dimension. These results are interpreted through a framework that suggests that social comparisons are automatic processes, the effects of which can be modified through conscious processing.

  10. Automated S/TEM metrology on advanced semiconductor gate structures

    NASA Astrophysics Data System (ADS)

    Strauss, M.; Arjavac, J.; Horspool, D. N.; Nakahara, K.; Deeb, C.; Hobbs, C.

    2012-03-01

    Alternate techniques for obatining metrology data from advanced semiconductor device structures may be required. Automated STEM-based dimensional metrology (CD-STEM) was developed for complex 3D geometries in read/write head metrology in teh hard disk drive industry. It has been widely adopted, and is the process of record for metrology. Fully automated S/TEM metrology on advanced semiconductor gate structures is viable, with good repeatability and robustness. Consistent automated throughput of 10 samples per hour was achieved. Automated sample preparation was developed with sufficient throughput and quality to support the automated CD-STEM.

  11. TEM studies of calcium phosphates for the understanding of biomineralization

    NASA Astrophysics Data System (ADS)

    Xin, Renlong

    Calcium phosphate (Ca-P) formation and bone minerals have been the focus of research for several decades because achievements in these areas could provide valuable insights into the understanding of biomineralization. In this thesis work, Ca-P formation, octacalcium phosphate (OCP) to hydroxyapatite (HA) transformation and bone minerals were systematically studied by transmission electron microscopy (TEM) techniques. Ca-P formations on various bioceramics in simulated body fluid and in rabbit muscle sites were investigated. The bioceramics included sintered bioglass RTM, A-W glass-ceramics, HA, alpha-tricalcium phosphate (TCP), beta-TCP and HA-TCP. The comparative studies showed that OCP formation occurred on all types of bioceramic surfaces in vitro and in vivo, except on beta-TCP; however HA formation did not occur on every type of bioceramics; it less likely occurred on the surfaces of HA and alpha-TCP. These findings were contradicted to the common statements in literatures. OCP to HA transformations in vitro and in vivo were observed by high-resolution TEM (HRTEM). The in vitro transformation was induced by electron beam irradiations of in situ TEM on synthetic OCP crystals. The in vivo transformation was revealed on rod-like HA precipitates formed in dog muscle sites. Based on HRTEM examinations and image simulations, OCP/HA crystallographic orientations were determined to be OCP (010) // HA (01¯0) and OCP (001) // HA (001¯), which differed from a well known model proposed by Brown et al. The minerals of cortical bone were extracted from human tibiae and rat femurs using 10% neutral ethylenediamine tetraacetic acid (EDTA) solution. TEM examinations showed that the dominance of bone minerals was plate-like and a few were needle-like. The length of most plate-like minerals ranged from 50 to 150 nm but could be up to 200 nm. To the author's knowledge, OCP structure was for the first time, identified in a number of plate-like bone minerals by selected area

  12. TEM Pump With External Heat Source And Sink

    NASA Technical Reports Server (NTRS)

    Nesmith, Bill J.

    1991-01-01

    Proposed thermoelectric/electromagnetic (TEM) pump driven by external source of heat and by two or more heat pipe radiator heat sink(s). Thermoelectrics generate electrical current to circulate liquid metal in secondary loop of two-fluid-loop system. Intended for use with space and terrestrial dual loop liquid metal nuclear reactors. Applications include spacecraft on long missions or terrestrial beacons or scientific instruments having to operate in remote areas for long times. Design modified to include multiple radiators, converters, and ducts, as dictated by particular application.

  13. Modeling of planar quasi-TEM superconducting transmission lines

    NASA Technical Reports Server (NTRS)

    Antsos, Dimitrios; Chew, Wilbert; Riley, A. L.; Hunt, Brian D.; Foote, Marc C.; Bajuk, Louis J.; Rascoe, Daniel L.; Cooley, Thomas W.

    1992-01-01

    An application of the phenomenological loss equivalence method (Lee and Itoh, 1989) in modeling the microwave behavior of planar quasi-TEM superconducting transmission lines is presented. For validation of the model, data are used from measurements of a YBCO superconducting thin-film coplanar-waveguide lowpass filter on a lanthanum aluminate substrate. Measured and modeled S-parameters of an existing superconducting coplanar waveguide lowpass filter agree to within 0.3 dB in magnitude and 0.5 radians in phase. Extracted values for penetration depth and real part of the conductivity of the superconducting film are within 10 percent of other researchers' findings.

  14. Low voltage TEM: influences on electron energy loss spectrometry experiments.

    PubMed

    Stöger-Pollach, M

    2010-08-01

    We discuss the advantages and disadvantages of electron energy loss spectrometry (EELS) a transmission electron microscope (TEM) at different high tensions. Instrumental effects such as energy resolution, spatial resolution, and point spread function of the detecting system, as well as physical effects like inelastic (Coloumb) delocalization and Cerenkov losses are dealt with. It is found that the actually available equipment is suitable for performing low voltage experiments. The energy resolution of a thermo-ionic emitter can be tremendously improved at lower energies, and the detector also has advantageous behaviour. (c) 2010 Elsevier Ltd. All rights reserved.

  15. Production of defects in metals by collision cascades: TEM experiments

    SciTech Connect

    Kirk, M.A.

    1996-01-01

    This paper reviews experimental TEM data on production of dislocation loops by low energy ion bombardment to low doses, as simulations of similar collision cascades produced by fast neutrons, in various metals and alloys. Dependence of vacancy dislocation loop formation on recoil energy, temperature and metal/alloy is examined. Emphasis is placed on effects on dilute alloy additions. A model for cascade melting is used to understand these effects; this will require an examination of the role of electron-phonon coupling in cascade cooling and recrystallization. Formation of interstitial dislocation loops as cascade defects and the effect of nearby surfaces are briefly discussed.

  16. A Fast 4-D TEM System for UXO Characterization

    DTIC Science & Technology

    2004-11-01

    eliminates the need to transport all gear back and forth between the field site and the hotel . At Aberdeen, the only piece of gear we transported back to...the hotel after work was the NT-32II transceiver. We had a problem with getting our GPS system operational and lost a few hours while we troubleshot...Orleans Mariott : U.S. Dept. of Defense. 9. Carlson, N.E., and Kenneth L. Zonge. The utility of horizontal component measurements in random-walk TEM

  17. TEM Pump With External Heat Source And Sink

    NASA Technical Reports Server (NTRS)

    Nesmith, Bill J.

    1991-01-01

    Proposed thermoelectric/electromagnetic (TEM) pump driven by external source of heat and by two or more heat pipe radiator heat sink(s). Thermoelectrics generate electrical current to circulate liquid metal in secondary loop of two-fluid-loop system. Intended for use with space and terrestrial dual loop liquid metal nuclear reactors. Applications include spacecraft on long missions or terrestrial beacons or scientific instruments having to operate in remote areas for long times. Design modified to include multiple radiators, converters, and ducts, as dictated by particular application.

  18. Comparison of Petrifilm Staph Express Count System with the bacteriological analytical manual direct-plating method for enumeration of Staphylococcus aureus in artificially contaminated hard cheese.

    PubMed

    Fedio, Willis M; Wendakoon, Chitra N; Zapata, Ruben; Carrillo, Christina; Browning, Paul

    2008-01-01

    The 3M Petrifilm Staph Express Count System was compared with the U.S. Food and Drug Administration's Bacteriological Analytical Manual (BAM) direct-plate count method for the enumeration of Staphylococcus aureus in 6 types of artificially contaminated hard cheese (Asiago, Cheddar, Gruyère, Parmesan, Romano, and Swiss). Five different samples of each cheese type were inoculated with S. aureus (ATCC 25923) to achieve low, medium, and high inoculum levels. S. aureus was enumerated by the Petrifilm and BAM methods, and the results were compared. Multivariate analysis of variance revealed no significant differences (P<0.05) between the 2 methods. The Petrifilm method compared favorably with the BAM procedure. The rapid method was more convenient to use, considerably faster, and less expensive to perform than the BAM method.

  19. Comparison of modified immunodiffusion and Bacteriological Analytical Manual (BAM) methods for detection of Salmonella in raw flesh and highly contaminated food types.

    PubMed

    Feldsine, P T; Falbo-Nelson, M T

    1995-01-01

    A wide variety of naturally contaminated and inoculated raw flesh and highly contaminated food types was analyzed by a modified immunodiffusion enrichment protocol and the Bacteriological Analytical Manual (BAM) method to determine the equivalence of these methods. This modification was developed by Agriculture Canada to allow addition of a high-temperature selective enrichment step in tetrathionate brilliant green broth at 42 degrees C while maintaining a 2-day total test time. Foods representing red meat, white meat, frog, and seafoods and one type of animal meal were evaluated. A total of 320 samples was tested, resulting in false negative rates of 5.2 and 3.5%, respectively, for the modified immunodiffusion and the BAM culture methods. The overall agreement rate was 96.9%.

  20. Analytical model for determination of parameters of helical structures in solution by small angle scattering: comparison of RecA structures by SANS.

    PubMed

    Lebedev, D V; Baitin, D M; Islamov, A Kh; Kuklin, A I; Shalguev, V Kh; Lanzov, V A; Isaev-Ivanov, V V

    2003-02-27

    The filament structures of the self-polymers of RecA proteins from Escherichia coli and Pseudomonas aeruginosa, their complexes with ATPgammaS, phage M13 single-stranded DNA (ssDNA) and the tertiary complexes RecA::ATPgammaS::ssDNA were compared by small angle neutron scattering. A model was developed that allowed for an analytical solution for small angle scattering on a long helical filament, making it possible to obtain the helical pitch and the mean diameter of the protein filament from the scattering curves. The results suggest that the structure of the filaments formed by these two RecA proteins, and particularly their complexes with ATPgammaS, is conservative.

  1. Comparison between a Direct-Flow SPR Immunosensor for Ampicillin and a Competitive Conventional Amperometric Device: Analytical Features and Possible Applications to Real Samples.

    PubMed

    Tomassetti, Mauro; Merola, Giovanni; Martini, Elisabetta; Campanella, Luigi; Sanzò, Gabriella; Favero, Gabriele; Mazzei, Franco

    2017-04-10

    In this research, we developed a direct-flow surface plasmon resonance (SPR) immunosensor for ampicillin to perform direct, simple, and fast measurements of this important antibiotic. In order to better evaluate the performance, it was compared with a conventional amperometric immunosensor, working with a competitive format with the aim of finding out experimental real advantages and disadvantages of two respective methods. Results showed that certain analytical features of the new SPR immunodevice, such as the lower limit of detection (LOD) value and the width of the linear range, are poorer than those of a conventional amperometric immunosensor, which adversely affects the application to samples such as natural waters. On the other hand, the SPR immunosensor was more selective to ampicillin, and measurements were more easily and quickly attained compared to those performed with the conventional competitive immunosensor.

  2. Statistical comparison of the results from six analytical chemistry laboratories of the mercury content of muscle tissue of two species of sharks.

    PubMed

    Walker, T I

    1977-01-01

    Statistical tests were carried out on the results of chemical analysis for total mercury concentrations of replicate samples of muscle tissue of school shark Galeorhinus australis (Macleay) and gummy shark Mustelus antarcticus Guenther from six independent analytical laboratories. These tests showed that one laboratory produced results 9% below the overall average of all results, another 1% below average while the other four were all 5% above average. Moreover, one laboratory had significantly lower scatter of results than the others, and the percentage scatter (standard error expressed as a percentage of the mean) in two of the laboratories tended to diminish as the magnitude of the results increased. Correction for what were concluded to be wild points indicated that the scatter for all laboratories was below 14%.

  3. Analytical comparison of the first- and second-order resonances for implementation of the dynamical Casimir effect in nonstationary circuit QED

    NASA Astrophysics Data System (ADS)

    Silva, E. L. S.; Dodonov, A. V.

    2016-12-01

    We investigate analytically and numerically the nonstationary circuit QED setup in which N independent qubits interact with a single mode of the Electromagnetic field confined in a resonator. We consider the harmonic time modulation of some parameter (atomic transition frequency or the atom-field coupling strength) and derive the unitary dynamics up to the second order in the modulation depth for N = 1 and N\\gg 1. It is shown that all the resonant phenomena that occur for modulation frequencies ∼ 2{ω }0 (where {ω }0 is the cavity frequency) also occur for the halved frequencies. However, in the latter case the associated transition rates are significantly smaller and the modulation of the coupling strength is less effective. The transition rates are evaluated explicitly and the prospects of employing the second-order resonances in the phenomena related to the dynamical Casimir effect are examined.

  4. Comparison of analytical predictions and verification flight test results for the performance of the Spacelab environmental control and life support subsystem as obtained during the 1st mission.

    PubMed

    Loser, H

    1985-12-01

    The environmental control and life support subsystem (ECLS) of the Spacelab module provides various functions which can be assigned to its various branches as follows: Thermal insulation from the external environment is achieved by the passive thermal control subsystem (PTCS). Rejection of the heat produced by the Spacelab subsystem equipment and by the various experiments is the task of the active thermal control subsystem (ATCS). Life support in the form of cabin air ventilation, oxygen/carbon dioxide partial pressure control; total pressure and air temperature/humidity control is achieved by the life support subsystem (LSS). In the first part of the paper a brief description of the various elements and loops forming the Spacelab ECLS will be given by discussing the PTCS, ATCS and LSS in some detail. Objective of the verification flight test program--as implied in the title already--is the verification of major requirements the ECLS has to comply with. Those requirements will then be comprehensively discussed in the second part of the paper. A description of the analytical approach is given in the third part of the paper. However, only those areas will be addressed which were included in the verification flight test program. A brief description of the flight instrumentation, the data transmission and collection follows then in the fourth part of the paper. In the fifth part of the paper the approach to select and compile flight test data obtained during the first mission (Shuttle flight STS 9) from November 28 till December 8, 1983 is illustrated. Flight test data are compared with the analytical predictions in form of examples. In the sixth and last portion of the paper the actual/measured performance is compared with the requirements, and conclusions are drawn with respect to comprehensiveness/accuracy of the flight test verification and the compliance of the Spacelab actual performance with the requirements.

  5. Comparison of Cerebrospinal Fluid Levels of Tau and Aß1-42 in Alzheimer’s disease and Frontotemporal Degeneration Using Two Analytical Platforms

    PubMed Central

    Irwin, David J.; McMillan, Corey T.; Toledo, Jon B.; Arnold, Steven E.; Shaw, Leslie M.; Wang, Li-San; Lee, Virginia M.-Y.; Trojanowski, John Q.; Grossman, Murray

    2012-01-01

    Objective To utilize values of cerebrospinal fluid (CSF) tau and ß-amyloid obtained from two different analytical immunoassays to differentiate Alzheimer’s disease (AD) from frontotemporal lobar degeneration (FTLD). Design CSF values of total tau (t-tau) and ß-amyloid (Aß1-42) obtained using the INNOTEST® ELISA were transformed using a linear regression model to equivalent values obtained using the INNO-BIA AlzBio3™ (xMAP Luminex) assay. Cutoff values obtained from the xMAP assay were developed in a series of autopsy-confirmed cases and cross-validated in another series of autopsy-confirmed samples using transformed ELISA values to assess sensitivity and specificity for differentiating AD from FTLD. Setting Tertiary memory disorders clinics and neuropathological and biomarker core centers. Participants 75 samples from patients with CSF data obtained from both assays were used for transformation of ELISA values. 40 autopsy-confirmed cases (30 AD, 10 FTLD) were used to establish diagnostic cutoff values, and then cross-validated in a second sample set of 21 autopsy-confirmed cases (11 AD, 10 FTLD) with transformed ELISA values. Main outcome measure Diagnostic accuracy using transformed biomarker values. Results Data obtained from both assays were highly correlated. The t-tau:Aß1-42 ratio had the highest correlation between measures (r=0.928, p<0.001) and high reliability of transformation (ICC=0.89). A cutoff of 0.34 for the t-tau:Aß1-42 ratio had 90% and 100% sensitivity and 96.7% and 91% specificity to differentiate FTLD cases in the validation and cross-validation samples, respectively. Conclusions Values from two analytical platforms can be transformed into equivalent units, which can distinguish AD from FTLD more accurately than the clinical diagnosis. PMID:22490326

  6. Comparison of different immunoassay methods to detect human anti-drug antibody using the WHO erythropoietin antibody reference panel for analytes.

    PubMed

    Shibata, Hiroko; Nishimura, Kazuko; Miyama, Chizuru; Tada, Minoru; Suzuki, Takuo; Saito, Yoshiro; Ishii-Watabe, Akiko

    2017-09-29

    Development of an appropriate assay to detect anti-drug antibody (ADA) is important for assessing immunogenicity to therapeutic protein products. However, characterizing ADA assay methods is difficult because human ADA as a reference standard is not available in most cases. We compared the analytical performance of three ligand-binding assay methods for ADA, namely, surface plasmon resonance (SPR), electrochemiluminescence (ECL), and biolayer interferometry (BLI) methods, by using the anti-erythropoietin (EPO) monoclonal antibody reference panel developed by the World Health Organization (WHO) in 2015. Dose-dependent binding responses were observed for all nine anti-EPO antibodies in the anti-EPO panel by the SPR and BLI methods. In contrast, the ECL method did not clearly detect binding of low-affinity anti-EPO antibodies. Regarding IgG2 and IgM antibodies derived from the same clone, IgG2 exhibited a higher binding response in the SPR assay, whereas the IgM binding response was higher than that of IgG2 in the ECL assay. In the case of the BLI method, there was no consistent pattern observed in the binding responses of IgG2 or IgM. Results of the anti-EPO antibody reference panel, which contains a variety of monoclonal antibodies, indicated that the ability to detect ADAs differed among these assay methods. Therefore, with ligand-binding assays, differences in assay platforms can affect the sensitivity and other characteristics of assays to detect ADAs. These results show that understanding the analytical performance of ADA assays is important for an appropriate assessment of immunogenicity. Our study also indicated the benefits of using the established human ADA reference panel to assess the assay methods for ADA detection. Copyright © 2017. Published by Elsevier B.V.

  7. Effects of in-pulse transverse relaxation in 3D ultrashort echo time sequences: analytical derivation, comparison to numerical simulation and experimental application at 3T.

    PubMed

    Springer, Fabian; Steidle, Günter; Martirosian, Petros; Claussen, Claus D; Schick, Fritz

    2010-09-01

    The introduction of ultrashort-echo-time-(UTE)-sequences to clinical whole-body MR scanners has opened up the field of MR characterization of materials or tissues with extremely fast signal decay. If the transverse relaxation time is in the range of the RF-pulse duration, approximation of the RF-pulse by an instantaneous rotation applied at the middle of the RF-pulse and immediately followed by free relaxation will lead to a distinctly underestimated echo signal. Thus, the regular Ernst equation is not adequate to correctly describe steady state signal under those conditions. The paper presents an analytically derived modified Ernst equation, which correctly describes in-pulse relaxation of transverse magnetization under typical conditions: The equation is valid for rectangular excitation pulses, usually applied in 3D UTE sequences. Longitudinal relaxation time of the specimen must be clearly longer than RF-pulse duration, which is fulfilled for tendons and bony structures as well as many solid materials. Under these conditions, the proposed modified Ernst equation enables adequate and relatively simple calculation of the magnetization of materials or tissues. Analytically derived data are compared to numerical results obtained by using an established Runge-Kutta-algorithm based on the Bloch equations. Validity of the new approach was also tested by systematical measurements of a solid polymeric material on a 3T whole-body MR scanner. Thus, the presented modified Ernst equation provides a suitable basis for T1 measurements, even in tissues with T2 values as short as the RF-pulse duration: independent of RF-pulse duration, the 'variable flip angle method' led to consistent results of longitudinal relaxation time T1, if the T2 relaxation time of the material of interest is known as well.

  8. An analytical comparison of gas gain in spherical, cylindrical and hemispherical low-pressure proportional counters intended for use in experimental microdosimetry

    NASA Astrophysics Data System (ADS)

    Broughton, David; Waker, Anthony J.

    2016-12-01

    Traditionally experimental microdosimetry has employed low pressure single cavity spherical Tissue Equivalent Proportional Counters (TEPCs). Multi-Element Tissue Equivalent Proportional Counters (METEPCs) with numerous cylindrical cavities have been constructed in order to increase sensitivity per unit volume; however existing METEPC designs are prohibitively complex and sensitive to motion and audible noise. This work proposes a novel hemispherical element with a wire-less anode ball as a solution to these issues. The gas gain characteristics of this hemispherical METEPC element were analyzed first for a single hemispherical TEPC to evaluate performance relative to current cylindrical and spherical counter designs that have been demonstrated experimentally to perform very well. This gain analysis evaluated relative avalanche size and the uniformity in maximum gain for electrons originating throughout the gas cavities of each of the three counters. Radial gas gain distributions for each counter were determined using both theoretical potential distributions as well as analytical equipotential distributions generated with ANSYS Maxwell (V. 14.0) to solve the Townsend equation. It was found that the hemispherical counter exhibits completely uniform gas gain for electrons approaching the anode from all directions and its avalanche region occupies only 3.5×10-3% of the entire gas cavity volume, whereas in the cylindrical and spherical counters the avalanche occupies 0.6% and 0.12% of the total respective gas cavity volumes. These analytical gas gain results are promising, suggesting that the hemisphere should exhibit uniform signal amplification throughout the gas cavity and if the recommended follow-up experimental work demonstrates the hemispherical counter works as anticipated it will be ready to be incorporated into an METEPC design.

  9. TEM transmission line coil with double nuclear capability.

    PubMed

    Erickson, Matthew G; Kurpad, Krishna N; Holmes, James H; Fain, Sean B

    2007-10-01

    MR imaging and spectroscopy requires RF fields of high homogeneity. Quadrature volume coils meeting this requirement include the birdcage coil and the TEM resonator. We describe here a quadrature volume coil designed around a modified coaxial transmission line in which multiple inner conductors are arrayed on a circular perimeter and surrounded by a common shield. Current antinodes are established at appropriate points on the inner conductors by series transmission line stubs, either open circuit or short circuit, which terminate the line. Quadrature phasing is generated by a novel circuit constructed from a pair of high-performance current baluns and a commercial quadrature hybrid. The coil is a "pure" TEM coil as it is simply a resonant transmission line. There is no mode structure to consider. The construction of a prototype quadrature four-element coil is described and preliminary test results from this coil in a 4.7T horizontal bore magnet are reported. A related double nuclear coil design for (3)He and (1)H in which two linear transmission line coils are arrayed on a circular perimeter and simultaneously tuned and matched to their respective frequencies is also described. Preliminary tests from this coil in a 1.5T clinical scanner are reported.

  10. A modified relativistic magnetron with TEM output mode

    NASA Astrophysics Data System (ADS)

    Shi, Di-Fu; Qian, Bao-Liang; Wang, Hong-Gang; Li, Wei; Ju, Jin-Chuan; Du, Guang-Xing

    2017-01-01

    A modified relativistic magnetron (RM) with TEM output mode is proposed. By setting the coupling slots at the bottom of the resonant cavities in the transmission region rather than in the interaction region, besides possessing the original RM's advantages of high power conversion efficiency and radiating the lowest order mode, the modified RM not only improves the compactness and miniaturization of the magnetic field system, which is beneficial to realize the RMs packed by a permanent magnet, but also improves the robustness of operating frequency to structural perturbations of the coupling slots, which contributes to optimize the RM performance by adjusting the coupling slot dimensions with a relatively stable operating frequency. In the three-dimensional particle-in-cell (PIC) simulation, the modified RM with a reduction of 27.2% in the weight of the coils, 35.8% in the occupied space of the coils, and 18.6% in the operating current, can output a relatively pure TEM mode, which has been demonstrated as the dominant output mode by simulation, corresponding to an output power of 495.0 MW and a power conversion efficiency of 56.4%, at the resonant frequency of 4.30 GHz. In addition, an output power of above 2 GW can also be obtained from the RM in simulations.

  11. Studying dynamic processes in liquids by TEM/STEM/DTEM

    NASA Astrophysics Data System (ADS)

    Abellan, Patricia; Evans, James; Woehl, Taylor; Jungjohann, Katherine; Parent, Lucas; Arslan, Ilke; Ristenpart, William; Browning, Nigel; Mater. Sci. Group Team; Microsc. Group Team; Catal. Sci. Group Collaboration; Ristenpart Res. Group Collaboration

    2013-03-01

    In order to study dynamic phenomena such as corrosion or catalysis, extreme environmental conditions must be reproduced around the specimen - these include high-temperatures, high-pressures, specific oxidizing/reducing atmospheres or a liquid environment. The use of environmental stages specifically designed to fit in any transmission electron microscope (TEM) allows us to apply the distinct capabilities of each instrument to study dynamic processes. Localized gas/fluid conditions are created around the sample and separated from the high vacuum inside the microscope using hermetically sealed windowed-cells. Advanced capabilities of these techniques include spatial resolutions of ~1 Angstrom or better in aberration corrected instruments or temporal resolutions in the microsecond-nanosecond range in a dynamic TEM (DTEM). Here, unique qualities of the DTEM that benefit the in-situ experiments with gas/fluid environmental cells will be discussed. We also present our results with a liquid stage allowing atomic resolution imaging of nanomaterials in a colloidal suspension, core EEL spectra acquisition, continuous flow, controlled growth of nanocrystals and systematic calibration of the effect of the electron dose on silver nuclei formation.

  12. Determination of Ro 48-3656 in rat plasma by reversed-phase high-performance liquid chromatography. Comparison of 1.5-microm nonporous silica to 3.5-microm porous silica analytical columns.

    PubMed

    Paasch, B D; Lin, Y S; Porter, S; Modi, N B; Barder, T J

    1997-12-19

    We describe a method for measuring Ro 48-3656 in EDTA rat plasma by neutral pH, reversed-phase high-performance liquid chromatography using a 1.5-microm nonporous silica, C18 analytical column and UV absorbance detection to support pharmacokinetic studies. We also describe a comparison of the 1.5-microm nonporous silica C18 column versus 3.5-microm porous silica C18 columns. The final method using the 1.5-microm nonporous silica column demonstrated good precision (of both quantification and retention time), accuracy and recovery, linearity of dilution and limit of quantification (40 ng/ml Ro 48-3656 using a 20 microl injection). Samples of neat EDTA rat plasma were prepared by ultrafiltration followed by direct injection onto the HPLC column.

  13. Comparison of analytical and experimental subsonic steady and unsteady pressure distributions for a high-aspect-ratio-supercritical wing model with oscillating control surfaces

    NASA Technical Reports Server (NTRS)

    Mccain, W. E.

    1982-01-01

    The results of a comparative study using the unsteady aerodynamic lifting surface theory, known as the Doublet Lattice method, and experimental subsonic steady- and unsteady-pressure measurements, are presented for a high-aspect-ratio supercritical wing model. Comparisons of pressure distributions due to wing angle of attack and control-surface deflections were made. In general, good correlation existed between experimental and theoretical data over most of the wing planform. The more significant deviations found between experimental and theoretical data were in the vicinity of control surfaces for both static and oscillatory control-surface deflections.

  14. Determination of the initial oxidation behavior of Zircaloy-4 by in-situ TEM

    NASA Astrophysics Data System (ADS)

    Harlow, Wayne; Ghassemi, Hessam; Taheri, Mitra L.

    2016-06-01

    The corrosion behavior of Zircaloy-4 (Zry-4), specifically by oxidation, is a problem of great importance as this material is critical for current nuclear reactor cladding. The early formation behavior and structure of the oxide layer during oxidation was studied using in-situ TEM techniques that allowed for Zry-4 to be monitored during corrosion. These environmental exposure experiments were coupled with precession electron diffraction to identify and quantify the phases present in the samples before and after the oxidation. Following short-term, high temperature oxidation, the dominant phase was revealed to be monoclinic ZrO2 in a columnar structure. These samples oxidized in-situ contained structures that correlated well with bulk Zry-4 subjected to autoclave treatment, which were used for comparison and validation of this technique. By using in-situ TEM the effect of microstructure features, such as grain boundaries, on oxidation behavior of an alloy can be studied. The technique presented herein holds the potential to be applied any alloy system to study these effects.

  15. SEM, TEM and SLEEM (scanning low energy electron microscopy) of CB2 steel after creep testing

    NASA Astrophysics Data System (ADS)

    Kasl, J.; Mikmeková, Š.; Jandová, D.

    2014-03-01

    The demand to produce electrical power with higher efficiency and with lower environmental pollution is leading to the use of new advanced materials in the production of power plant equipment. To understand the processes taking place in parts produced from these materials during their operation under severe conditions (such as high temperature, high stress, and environmental corrosion) requires detailed evaluation of their substructure. It is usually necessary to use transmission electron microscopy (TEM). However, this method is very exacting and time-consuming. So there is an effort to use new scanning electron microscopy techniques instead of TEM. One of them is scanning low energy electron microscopy (SLEEM). This paper deals with an assessment of the possibility to use SLEEM for describing the substructure of creep resistant steel CB2 after long-term creep testing. In the SLEEM images more information is contained about the microstructure of the material in comparison with standard scanning electron microscopy. Study of materials using slow and very slow electrons opens the way to better understanding their microstructures.

  16. High-resolution methane emission estimates using the InTEM inversion system

    NASA Astrophysics Data System (ADS)

    Connors, S.; Manning, A.; Robinson, A. D.; Riddick, S. N.; Forster, G.; Oram, D.; O'Doherty, S.; Harris, N. R. P.

    2014-12-01

    There is a growing need for comparisons between emission estimates produced using bottom-up and top-down techniques at high spatial resolution. In response to this, an inversion approach, InTEM, was adapted to estimate methane emissions for a region in the South East of the UK (~100 x 150 km). We present results covering a 2-year period (July 2012 - July 2014) in which atmospheric methane concentrations were recorded at 1 - 2 minute time-steps at four locations within the region of interest. Precise measurements were obtained using gas chromatography with flame ionisation detection (GC-FID) for all sites except one, which used a PICARRO Cavity Ring-Down Spectrometer (CRDS). These observations, along with the UK Met Office's Lagrangian particle dispersion model (NAME) were used within InTEM to produce the methane emission fields. Emission estimates were produced at varying spatial resolutions, for annual and seasonal time frames . We present results indicating the optimum number of observation sites required for this region, and how this can affect our uncertainty estimates. These results are compared with the UK National Atmospheric Emissions Inventory (NAEI) which is compiled using bottom-up methods and available at 1x1 km resolution. To our knowledge, no inversion technique has been implemented on such a fine spatial resolution. This is a pilot project which, given proof of concept, could be scaled up as an alternative method for producing national scale emission inventories.

  17. Estimation of Survival Probabilities for Use in Cost-effectiveness Analyses: A Comparison of a Multi-state Modeling Survival Analysis Approach with Partitioned Survival and Markov Decision-Analytic Modeling.

    PubMed

    Williams, Claire; Lewsey, James D; Mackay, Daniel F; Briggs, Andrew H

    2017-05-01

    Modeling of clinical-effectiveness in a cost-effectiveness analysis typically involves some form of partitioned survival or Markov decision-analytic modeling. The health states progression-free, progression and death and the transitions between them are frequently of interest. With partitioned survival, progression is not modeled directly as a state; instead, time in that state is derived from the difference in area between the overall survival and the progression-free survival curves. With Markov decision-analytic modeling, a priori assumptions are often made with regard to the transitions rather than using the individual patient data directly to model them. This article compares a multi-state modeling survival regression approach to these two common methods. As a case study, we use a trial comparing rituximab in combination with fludarabine and cyclophosphamide v. fludarabine and cyclophosphamide alone for the first-line treatment of chronic lymphocytic leukemia. We calculated mean Life Years and QALYs that involved extrapolation of survival outcomes in the trial. We adapted an existing multi-state modeling approach to incorporate parametric distributions for transition hazards, to allow extrapolation. The comparison showed that, due to the different assumptions used in the different approaches, a discrepancy in results was evident. The partitioned survival and Markov decision-analytic modeling deemed the treatment cost-effective with ICERs of just over £16,000 and £13,000, respectively. However, the results with the multi-state modeling were less conclusive, with an ICER of just over £29,000. This work has illustrated that it is imperative to check whether assumptions are realistic, as different model choices can influence clinical and cost-effectiveness results.

  18. Estimation of Survival Probabilities for Use in Cost-effectiveness Analyses: A Comparison of a Multi-state Modeling Survival Analysis Approach with Partitioned Survival and Markov Decision-Analytic Modeling

    PubMed Central

    Williams, Claire; Lewsey, James D.; Mackay, Daniel F.; Briggs, Andrew H.

    2016-01-01

    Modeling of clinical-effectiveness in a cost-effectiveness analysis typically involves some form of partitioned survival or Markov decision-analytic modeling. The health states progression-free, progression and death and the transitions between them are frequently of interest. With partitioned survival, progression is not modeled directly as a state; instead, time in that state is derived from the difference in area between the overall survival and the progression-free survival curves. With Markov decision-analytic modeling, a priori assumptions are often made with regard to the transitions rather than using the individual patient data directly to model them. This article compares a multi-state modeling survival regression approach to these two common methods. As a case study, we use a trial comparing rituximab in combination with fludarabine and cyclophosphamide v. fludarabine and cyclophosphamide alone for the first-line treatment of chronic lymphocytic leukemia. We calculated mean Life Years and QALYs that involved extrapolation of survival outcomes in the trial. We adapted an existing multi-state modeling approach to incorporate parametric distributions for transition hazards, to allow extrapolation. The comparison showed that, due to the different assumptions used in the different approaches, a discrepancy in results was evident. The partitioned survival and Markov decision-analytic modeling deemed the treatment cost-effective with ICERs of just over £16,000 and £13,000, respectively. However, the results with the multi-state modeling were less conclusive, with an ICER of just over £29,000. This work has illustrated that it is imperative to check whether assumptions are realistic, as different model choices can influence clinical and cost-effectiveness results. PMID:27698003

  19. Comparative quantification and statistical analysis of η′ and η precipitates in aluminum alloy AA7075-T651 by TEM and AFM

    SciTech Connect

    Garcia-Garcia, Adrian Luis Dominguez-Lopez, Ivan Lopez-Jimenez, Luis Barceinas-Sanchez, J.D. Oscar

    2014-01-15

    Quantification of nanometric precipitates in metallic alloys has been traditionally performed using transmission electron microscopy, which is nominally a low throughput technique. This work presents a comparative study of quantification of η′ and η precipitates in aluminum alloy AA7075-T651 using transmission electron microscopy (TEM) and non-contact atomic force microscopy (AFM). AFM quantification was compared with 2-D stereological results reported elsewhere. Also, a method was developed, using specialized software, to characterize nanometric size precipitates observed in dark-field TEM micrographs. Statistical analysis of the quantification results from both measurement techniques supports the use of AFM for precipitate characterization. Once the precipitate stoichiometry has been determined by appropriate analytical techniques like TEM, as it is the case for η′ and η in AA7075-T651, the relative ease with which specimens are prepared for AFM analysis could be advantageous in product and process development, and quality control, where a large number of samples are expected for analysis on a regular basis. - Highlights: • Nanometric MgZn{sub 2} precipitates in AA7075-T651 were characterized using AFM and TEM. • Phase-contrast AFM was used to differentiate metal matrix from MgZn{sub 2} precipitates. • TEM and AFM micrographs were analyzed using commercially available software. • AFM image analysis and TEM 2-D stereology render statistically equivalent results.

  20. A study of the rotor wake of a small-scale rotor model in forward flight using laser light sheet flow visualization with comparisons to analytical models

    NASA Technical Reports Server (NTRS)

    Ghee, Terence A.; Elliott, Joe W.

    1992-01-01

    An experimental investigation was conducted in the 14 by 22 ft subsonic tunnel at NASA Langley Research Center to quantify the rotor wake behind a scale model helicopter rotor in forward flight (mu = 0.15 and 0.23) at one thrust level (C sub T = 0.0064). The rotor system used in the present test consisted of a four-bladed, fully articulated hub and utilized blades of rectangular planform with a NACA-0012 airfoil section. A laser light sheet, seeded with propylene glycol smoke, was used to visualize the flow in planes parallel and perpendicular to the freestream flow. Quantitative measurements of vortex location, vertical skew angle, and vortex particle void radius were obtained for vortices in the flow; convective velocities were obtained for blade tip vortices. Comparisons were made between the experimental results and the wake geometry generated by computational predictions. The results of these comparisons show that the interaction between wake vortex structures is an important consideration for correctly predicting the wake geometry.

  1. Minimum SNR and acquisition for bias-free estimation of fractional anisotropy in diffusion tensor imaging - a comparison of two analytical techniques and field strengths.

    PubMed

    Seo, Youngseob; Wang, Zhiyue J; Morriss, Michael C; Rollins, Nancy K

    2012-10-01

    Although it is known that low signal-to-noise ratio (SNR) can affect tensor metrics, few studies reporting disease or treatment effects on fractional anisotropy (FA) report SNR; the implicit assumption is that SNR is adequate. However, the level at which low SNR causes bias in FA may vary with tissue FA, field strength and analytical methodology. We determined the SNR thresholds at 1.5 T vs. 3 T in regions of white matter (WM) with different FA and compared FA derived using manual region-of-interest (ROI) analysis to tract-based spatial statistics (TBSS), an operator-independent whole-brain analysis tool. Using ROI analysis, SNR thresholds on our hardware-software magnetic resonance platforms were 25 at 1.5 T and 20 at 3 T in the callosal genu (CG), 40 at 1.5 and 3 T in the anterior corona radiata (ACR), and 50 at 1.5 T and 70 at 3 T in the putamen (PUT). Using TBSS, SNR thresholds were 20 at 1.5 T and 3 T in the CG, and 35 at 1.5 T and 40 at 3 T in the ACR. Below these thresholds, the mean FA increased logarithmically, and the standard deviations widened. Achieving bias-free SNR in the PUT required at least nine acquisitions at 1.5 T and six acquisitions at 3 T. In the CG and ACR, bias-free SNR was achieved with at least three acquisitions at 1.5 T and one acquisition at 3 T. Using diffusion tensor imaging (DTI) to study regions of low FA, e.g., basal ganglia, cerebral cortex, and WM in the abnormal brain, SNR should be documented. SNR thresholds below which FA is biased varied with the analytical technique, inherent tissue FA and field strength. Studies using DTI to study WM injury should document that bias-free SNR has been achieved in the region of the brain being studied as part of quality control. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Active compensation of aperture discontinuities for WFIRST-AFTA: analytical and numerical comparison of propagation methods and preliminary results with a WFIRST-AFTA-like pupil

    NASA Astrophysics Data System (ADS)

    Mazoyer, Johan; Pueyo, Laurent; Norman, Colin; N'Diaye, Mamadou; van der Marel, Roeland P.; Soummer, Rémi

    2016-03-01

    The new frontier in the quest for the highest contrast levels in the focal plane of a coronagraph is now the correction of the large diffraction artifacts introduced at the science camera by apertures of increasing complexity. Indeed, the future generation of space- and ground-based coronagraphic instruments will be mounted on on-axis and/or segmented telescopes; the design of coronagraphic instruments for such observatories is currently a domain undergoing rapid progress. One approach consists of using two sequential deformable mirrors (DMs) to correct for aberrations introduced by secondary mirror structures and segmentation of the primary mirror. The coronagraph for the WFIRST-AFTA mission will be the first of such instruments in space with a two-DM wavefront control system. Regardless of the control algorithm for these multiple DMs, they will have to rely on quick and accurate simulation of the propagation effects introduced by the out-of-pupil surface. In the first part of this paper, we present the analytical description of the different approximations to simulate these propagation effects. In Appendix A, we prove analytically that in the special case of surfaces inducing a converging beam, the Fresnel method yields high fidelity for simulations of these effects. We provide numerical simulations showing this effect. In the second part, we use these tools in the framework of the active compensation of aperture discontinuities (ACAD) technique applied to pupil geometries similar to WFIRST-AFTA. We present these simulations in the context of the optical layout of the high-contrast imager for complex aperture telescopes, which will test ACAD on a optical bench. The results of this analysis show that using the ACAD method, an apodized pupil Lyot coronagraph, and the performance of our current DMs, we are able to obtain, in numerical simulations, a dark hole with a WFIRST-AFTA-like. Our numerical simulation shows that we can obtain contrast better than 2×10-9 in

  3. Poster - Thur Eve - 68: Evaluation and analytical comparison of different 2D and 3D treatment planning systems using dosimetry in anthropomorphic phantom.

    PubMed

    Khosravi, H R; Nodehi, Mr Golrokh; Asnaashari, Kh; Mahdavi, S R; Shirazi, A R; Gholami, S

    2012-07-01

    The aim of this study was to evaluate and analytically compare different calculation algorithms applied in our country radiotherapy centers base on the methodology developed by IAEA for treatment planning systems (TPS) commissioning (IAEA TEC-DOC 1583). Thorax anthropomorphic phantom (002LFC CIRS inc.), was used to measure 7 tests that simulate the whole chain of external beam TPS. The dose were measured with ion chambers and the deviation between measured and TPS calculated dose was reported. This methodology, which employs the same phantom and the same setup test cases, was tested in 4 different hospitals which were using 5 different algorithms/ inhomogeneity correction methods implemented in different TPS. The algorithms in this study were divided into two groups including correction based and model based algorithms. A total of 84 clinical test case datasets for different energies and calculation algorithms were produced, which amounts of differences in inhomogeneity points with low density (lung) and high density (bone) was decreased meaningfully with advanced algorithms. The number of deviations outside agreement criteria was increased with the beam energy and decreased with advancement of the TPS calculation algorithm. Large deviations were seen in some correction based algorithms, so sophisticated algorithms, would be preferred in clinical practices, especially for calculation in inhomogeneous media. Use of model based algorithms with lateral transport calculation, is recommended. Some systematic errors which were revealed during this study, is showing necessity of performing periodic audits on TPS in radiotherapy centers. © 2012 American Association of Physicists in Medicine.

  4. Radiative transfer equation for predicting light propagation in biological media: comparison of a modified finite volume method, the Monte Carlo technique, and an exact analytical solution.

    PubMed

    Asllanaj, Fatmir; Contassot-Vivier, Sylvain; Liemert, André; Kienle, Alwin

    2014-01-01

    We examine the accuracy of a modified finite volume method compared to analytical and Monte Carlo solutions for solving the radiative transfer equation. The model is used for predicting light propagation within a two-dimensional absorbing and highly forward-scattering medium such as biological tissue subjected to a collimated light beam. Numerical simulations for the spatially resolved reflectance and transmittance are presented considering refractive index mismatch with Fresnel reflection at the interface, homogeneous and two-layered media. Time-dependent as well as steady-state cases are considered. In the steady state, it is found that the modified finite volume method is in good agreement with the other two methods. The relative differences between the solutions are found to decrease with spatial mesh refinement applied for the modified finite volume method obtaining <2.4%. In the time domain, the fourth-order Runge-Kutta method is used for the time semi-discretization of the radiative transfer equation. An agreement among the modified finite volume method, Runge-Kutta method, and Monte Carlo solutions are shown, but with relative differences higher than in the steady state.

  5. Comparison of two analytical methods for the evaluation of the complexed metal in fertilizers and the complexing capacity of complexing agents.

    PubMed

    Villén, María; Lucena, Juan José; Cartagena, M Carmen; Bravo, Raquel; García-Mina, Josemaría; de la Hinojosa, M Ignacia Martín

    2007-07-11

    The aim of this research is to develop an analytical methodology for the determination of complexed element in fertilizers and, then, to obtain an adequate criteria for the inclusion of these products in European Regulations on Fertilizers. This paper compares the CEN method EN 13366:2001, based on the retention of the cations into a sulfonated resin, and an AOAC modified method, based on the precipitation of the inorganic forms at pH 9. A limited interlaboratory trial was carried out to demonstrate the applicability of the AOAC modified method and to study the effect of the removal of organic compounds and the addition of a matrix modifier solution before the element quantification. Then, a global interlaboratory trial was developed to evaluate the validation and quality parameters of the method. As a second objective, the AOAC modified method was applied to the determination of the complexing capacity of complexing agents based on lignosulfonates and amino acids. The AOAC modified method was the choice methodology because it is adequate for the determination of complexing capacity of micronutrients in fertilizer.

  6. Screening biological stains with qPCR versus lateral flow immunochromatographic test strips: a quantitative comparison using analytical figures of merit.

    PubMed

    Oechsle, Crystal Simson; Haddad, Sandra; Sgueglia, Joanne B; Grgicak, Catherine M

    2014-01-01

    Biological fluid identification is an important facet of evidence examination in forensic laboratories worldwide. While identifying bodily fluids may provide insight into which downstream DNA methods to employ, these screening techniques consume a vital portion of the available evidence, are usually qualitative, and rely on visual interpretation. In contrast, qPCR yields information regarding the amount and proportion of amplifiable genetic material. In this study, dilution series of either semen or male saliva were prepared in either buffer or female blood. The samples were subjected to both lateral flow immunochromatographic test strips and qPCR analysis. Analytical figures of merit-including sensitivity, minimum distinguishable signal (MDS) and limit of detection (LOD)-were calculated and compared between methods. By applying the theory of the propagation of random errors, LODs were determined to be 0.05 μL of saliva for the RSID™ Saliva cards, 0.03 μL of saliva for Quantifiler(®) Duo, and 0.001 μL of semen for Quantifiler(®) Duo. In conclusion, quantitative PCR was deemed a viable and effective screening method for subsequent DNA profiling due to its stability in different matrices, sensitivity, and low limits of detection.

  7. Laser Based In Situ Techniques: Novel Methods for Generating Extreme Conditions in TEM Samples

    SciTech Connect

    Taheri, M; Lagrange, T; Reed, B; Armstrong, M; Campbell, G; DeHope, W; Kim, J; King, W; Masiel, D; Browning, N

    2008-02-25

    The Dynamic Transmission Electron Microscope (DTEM) is introduced as a novel tool for in situ processing of materials. Examples of various types of dynamic studies outline the advantages and differences of laser-based heating in the DTEM in comparison to conventional (resistive) heating in situ TEM methods. We demonstrate various unique capabilities of the drive laser, namely, in situ processing of nanoscale materials, rapid and high temperature phase transformations, and controlled thermal activation of materials. These experiments would otherwise be impossible without the use of the DTEM drive laser. Thus, the potential of the DTEM to as a new technique to process and characterize the growth of a myriad of micro and nanostructures is demonstrated.

  8. (S)TEM analysis of functional transition metal oxides

    NASA Astrophysics Data System (ADS)

    Chi, Miaofang

    Perovskite vanadates (AVO3) form an ideal family to study the structure-property relationships in transition metal oxides because their physical properties can easily be tailored by varying the A-site cations. (S)TEM is an ideal tool for this type of study due to its capacity for simultaneous imaging and chemical analysis. Determination of the oxidation state of vanadium in complex oxides have been carried out by electron energy loss spectroscopy. SrVO3/LaAlO3 is then studied both experimentally and theoretically as a prototype system. Extra electrons have been detected on the interface layer, and further proven to originate mainly from a change in the local bonding configuration of V at the La-O terminated substrate surface. Cr-containing stainless steel deposited with a LaCrO3 thin-film layer is a promising interconnect material of Solid Oxide Fuel Cells (SOFC). Our investigation on its microstructural evolution reveals that the LaCrO 3 thin film plays a role in inhibiting the growth of an oxide layer on the metal surface and thus protects the surface of the stainless steel. Ca-doped LaCoO3 is a promising SOFC cathode material. The domain structures and the oxidation state of Co in Ca-doped LaCoO3, which are directly related to its mechanical properties and electronic conductivity, are investigated by in-situ TEM and EELS. The formation of microcracks is observed during thermal cycles. Ca-doping in LaCoO3 is shown to not only improve the electronic conductivity of the material, but is also likely to strengthen the grain boundaries. The realization of its application in SOFCs depends on depressing the ferroelastisity to reduce strain formation during thermal cycles. The application of the (S)TEM techniques used for studying the perovskite systems are further extended to other compounds containing transition metal elements. The refractory minerals from Comet 81 P/Wild-2 are studied to investigate the formation of the early solar system. A relatively high Ti3+/Ti 4

  9. Analysis of the radiation shielding of the bunker of a 230MeV proton cyclotron therapy facility; comparison of analytical and Monte Carlo techniques.

    PubMed

    Sunil, C

    2016-04-01

    The neutron ambient dose equivalent outside the radiation shield of a proton therapy cyclotron vault is estimated using the unshielded dose equivalent rates and the attenuation lengths obtained from the literature and by simulations carried out with the FLUKA Monte Carlo radiation transport code. The source terms derived from the literature and that obtained from the FLUKA calculations differ by a factor of 2-3, while the attenuation lengths obtained from the literature differ by 20-40%. The instantaneous dose equivalent rates outside the shield differ by a few orders of magnitude, not only in comparison with the Monte Carlo simulation results, but also with the results obtained by line of sight attenuation calculations with the different parameters obtained from the literature. The attenuation of neutrons caused by the presence of bulk iron, such as magnet yokes is expected to reduce the dose equivalent by as much as a couple of orders of magnitude outside the shield walls.

  10. Normality in Analytical Psychology

    PubMed Central

    Myers, Steve

    2013-01-01

    Although C.G. Jung’s interest in normality wavered throughout his career, it was one of the areas he identified in later life as worthy of further research. He began his career using a definition of normality which would have been the target of Foucault’s criticism, had Foucault chosen to review Jung’s work. However, Jung then evolved his thinking to a standpoint that was more aligned to Foucault’s own. Thereafter, the post Jungian concept of normality has remained relatively undeveloped by comparison with psychoanalysis and mainstream psychology. Jung’s disjecta membra on the subject suggest that, in contemporary analytical psychology, too much focus is placed on the process of individuation to the neglect of applications that consider collective processes. Also, there is potential for useful research and development into the nature of conflict between individuals and societies, and how normal people typically develop in relation to the spectrum between individuation and collectivity. PMID:25379262

  11. Correlation Analysis of TEM Images of Nanocrystal Molecules

    SciTech Connect

    Micheel, Christine; Zanchet, Daniele; Alivisatos, A. Paul

    2008-05-21

    Quantitative characterizataion of images of naocrystals and nanostructures is a challenging but important task. The development and optimization of methods for the construction of complex nanostructures rely on imaging techniques. Computer programs were developed to quantify TEM images of nanocrystal/DNA nanostructures, and results are presented for heterodimers annd trimers of gold nanocrystals. The programs presented here have also been used to analyze more complex trimers and tetramers linked by branched DNA, as well as for structures made from attaching gold nanocrystals to CdSe/ZnS core-shell quantum dots. This work has the additional goal of enabling others to quickly and easily adapt the methods for their own use.

  12. AFM, SEM and TEM Studies on Porous Anodic Alumina

    PubMed Central

    2010-01-01

    Porous anodic alumina (PAA) has been intensively studied in past decade due to its applications for fabricating nanostructured materials. Since PAA’s pore diameter, thickness and shape vary too much, a systematical study on the methods of morphology characterization is meaningful and essential for its proper development and utilization. In this paper, we present detailed AFM, SEM and TEM studies on PAA and its evolvements with abundant microstructures, and discuss the advantages and disadvantages of each method. The sample preparation, testing skills and morphology analysis are discussed, especially on the differentiation during characterizing complex cross-sections and ultrasmall nanopores. The versatility of PAAs is also demonstrated by the diversity of PAAs’ microstructure. PMID:20672104

  13. Identification of cooked bone using TEM imaging of bone collagen.

    PubMed

    Koon, Hannah E C

    2012-01-01

    Mild heating (≤100° C, 1 h)-typical of cooking-does not lead to detectable changes in any biochemical parameter yet measured; consequently bones that have been cooked, but which have not reached a temperature that will induce charring go undetected. We have used a microscopy based approach to investigate changes in the organization of the bone protein, collagen, as it is heated, using bone from heating experiments, short term burials, and archaeological sites. The work has revealed that the presence of a mineral matrix stabilizes the collagen enabling the damage to accumulate, but preventing it from causing immediate gelatinization. Once the mineral is removed, the damage can be observed using appropriate visualization methods. This chapter describes the transmission electron microscopy (TEM) technique that has been used to detect cooked bone by visualizing minor heat-induced damage at the level of the collagen fibril.

  14. TSAR modeling of a TEM horn and surrounding structure

    SciTech Connect

    Ng, W.C.; Pennock, S.T.

    1993-11-01

    Modeling of a TEM horn was performed with the TSAR FDTD electromagnetics code. The modeling was done in stages, beginning with the simplest case, the bare antenna itself. Complexity was added in the form of a dielectric lens, an enclosing cylinder, a layer of absorber inside the cylinder, resistive terminations between the horn and cylinder, and a flat plate over all, electrically separate from the cylinder. The final configuration included all of the above, plus a ring of ferrite inside the cylinder, just ahead of the horn. Predictions of the far-field were made at roughly ten degree increments, more closely spaced near boresight, in both vertical and horizontal planes, through the antenna`s centerline. Time histories at those points were evaluated, and from the time histories power densities were calculated. Both time histories and power densities will be presented for the configurations modeled.

  15. Production of defects in metals by collision cascades: TEM experiments

    SciTech Connect

    Kirk, M.A.

    1995-03-01

    This paper reviews experimental TEM data on production of dislocation loops by low energy ion bombardment to low doses, as simulations of similar collision cascades produced by fast neutron irradiation, in various metals and alloys. The dependence of vacancy dislocation loop formation on recoil energy, sample temperature, and specific metal or alloy will be examined. Special emphasis will be placed on the effects of dilute alloy additions. A model for cascade melting will be employed to understand these effects, and will require an examination of the role of electron-phonon coupling in cascade cooling and recrystallization. The formation of interstitial dislocation loops as cascade defects, and the influence of the nearby surfaces in these experiments is briefly discussed.

  16. Examination of subaerially altered basaltic glass with TEM and EELS

    SciTech Connect

    Luo, J.-S.

    1998-06-17

    We have examined the weathered surfaces of 720 year old Hawaiian basalt glasses that were recovered from a subaerial environment with high-resolution transmission electron microscopy (TEM) and energy filtered imaging and electron energy loss spectroscopy (EELS) techniques. Whereas the alteration products (palagonite) were physically detached from the underlying glass in most samples, a gel-like amorphous layer was observed adjacent to the glass in a few samples. To our knowledge, this is the first time a gel layer has been observed on weathered basalt. This is significant because analogous gel layers have been observed on nuclear waste glasses reacted in laboratory tests, and this demonstrates an important similarity in the mechanisms of the weathering of basalt and the corrosion of waste glasses.

  17. Wideband TEM-TE11 mode convertor for HPM applications.

    NASA Astrophysics Data System (ADS)

    Bykov, D. N.; Bykov, N. M.; Kurkan, I. K.

    2017-05-01

    The mode convertor design of fundamental coaxial TEM to the lowest asymmetric TE11-mode of a circular waveguide was proposed and optimized with ANSYS HFSS software. It includes axially aligned parts: the input coaxial line with the high voltage insulator, conical coaxial matching line, wave-coax transition section and output circular waveguide. The most losses in this type of convertor caused by the wave of coaxial TE11-mode running back to the microwave source. To minimize these losses, there is the matching conical coaxial line with the cut-off insertion for coaxial TE11-mode. Characteristics of the convertor are as follows: the maximum input peak power - 3GW, the input impedance - 28Ohm, the central operating frequency - 1.14GHz. The power conversion efficiency to the output mode is from 90% upto 100% in the frequency band of 20%.

  18. Onion cells after high pressure and thermal processing: comparison of membrane integrity changes using different analytical methods and impact on tissue texture.

    PubMed

    Gonzalez, Maria E; Anthon, Gordon E; Barrett, Diane M

    2010-09-01

    Two different analytical methods were evaluated for their capacity to provide quantitative information on onion cell membrane permeability and integrity after high pressure and thermal processing and to study the impact of these processing treatments on cell compartmentalization and texture quality. To determine changes in cell membrane permeability and/or integrity the methodologies utilized were: (1) measurement of a biochemical product, pyruvate, formed as a result of membrane permeabilization followed by enzymatic activity and (2) leakage of electrolytes into solution. These results were compared to previously determined methods that quantified cell viability and ¹H-NMR T(2) of onions. These methods allowed for the monitoring of changes in the plasma and tonoplast membranes after high pressure or thermal processing. High pressure treatments consisted of 5 min holding times at 50, 100, 200, 300, or 600 MPa. Thermal treatments consisted of 30 min water bath exposure to 40, 50, 60, 70, or 90 °C. There was strong agreement between the methods in the determination of the ranges of high pressure and temperature that induce changes in the integrity of the plasma and tonoplast membranes. Membrane rupture could clearly be identified at 300 MPa and above in high pressure treatments and at 60 °C and above in the thermal treatments. Membrane destabilization effects could already be visualized following the 200 MPa and 50 °C treatments. The texture of onions was influenced by the state of the membranes and was abruptly modified once membrane integrity was lost. In this study, we used chemical, biochemical, and histological techniques to obtain information on cell membrane permeability and onion tissue integrity after high pressure and thermal processing. Because there was strong agreement between the various methods used, it is possible to implement something relatively simple, such as ion leakage, into routine quality assurance measurements to determine the severity of

  19. Determination of medicinal and illicit drugs in post mortem dental hard tissues and comparison with analytical results for body fluids and hair samples.

    PubMed

    Klima, Miriam; Altenburger, Markus J; Kempf, Jürgen; Auwärter, Volker; Neukamm, Merja A

    2016-08-01

    In burnt or skeletonized bodies dental hard tissue sometimes is the only remaining specimen available. Therefore, it could be used as an alternative matrix in post mortem toxicology. Additionally, analysis of dental tissues could provide a unique retrospective window of detection. For forensic interpretation, routes and rates of incorporation of different drugs as well as physicochemical differences between tooth root, tooth crown and carious material have to be taken into account. In a pilot study, one post mortem tooth each from three drug users was analyzed for medicinal and illicit drugs. The pulp was removed in two cases; in one case the tooth was root canal treated. The teeth were separated into root, crown and carious material and drugs were extracted from the powdered material with methanol under ultrasonication. The extracts were screened for drugs by LC-MS(n) (ToxTyper™) and quantitatively analyzed with LC-ESI-MS/MS in MRM mode. The findings were compared to the analytical results for cardiac blood, femoral blood, urine, stomach content and hair. In dental hard tissues, 11 drugs (amphetamine, MDMA, morphine, codeine, norcodeine, methadone, EDDP, fentanyl, tramadol, diazepam, nordazepam, and promethazine) could be detected and concentrations ranged from approximately 0.13pg/mg to 2,400pg/mg. The concentrations declined in the following order: carious material>root>crown. Only the root canal treated tooth showed higher concentrations in the crown than in the root. In post mortem toxicology, dental hard tissue could be a useful alternative matrix facilitating a more differentiated consideration of drug consumption patterns, as the window of detection seems to overlap those for body fluids and hair. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  20. Measuring patients' priorities using the Analytic Hierarchy Process in comparison with Best-Worst-Scaling and rating cards: methodological aspects and ranking tasks.

    PubMed

    Schmidt, Katharina; Babac, Ana; Pauer, Frédéric; Damm, Kathrin; von der Schulenburg, J-Matthias

    2016-12-01

    Identifying patient priorities and preference measurements have gained importance as patients claim a more active role in health care decision making. Due to the variety of existing methods, it is challenging to define an appropriate method for each decision problem. This study demonstrates the impact of the non-standardized Analytic Hierarchy Process (AHP) method on priorities, and compares it with Best-Worst-Scaling (BWS) and ranking card methods. We investigated AHP results for different Consistency Ratio (CR) thresholds, aggregation methods, and sensitivity analyses. We also compared criteria rankings of AHP with BWS and ranking cards results by Kendall's tau b. The sample for our decision analysis consisted of 39 patients with rare diseases and mean age of 53.82 years. The mean weights of the two groups of CR ≤ 0.1 and CR ≤ 0.2 did not differ significantly. For the aggregation by individual priority (AIP) method, the CR was higher than for aggregation by individual judgment (AIJ). In contrast, the weights of AIJ were similar compared to AIP, but some criteria's rankings differed. Weights aggregated by geometric mean, median, and mean showed deviating results and rank reversals. Sensitivity analyses showed instable rankings. Moderate to high correlations between the rankings resulting from AHP and BWS. Limitations were the small sample size and the heterogeneity of the patients with different rare diseases. In the AHP method, the number of included patients is associated with the threshold of the CR and choice of the aggregation method, whereas both directions of influence could be demonstrated. Therefore, it is important to implement standards for the AHP method. The choice of method should depend on the trade-off between the burden for participants and possibilities for analyses.

  1. Modeling of slender laminated piezoelastic beams with resistive electrodes—comparison of analytical results with three-dimensional finite element calculations

    NASA Astrophysics Data System (ADS)

    Buchberger, G.; Schoeftner, J.

    2013-03-01

    In this work a theory for a slender piezoelectric laminated beam taking into account lossy electrodes is developed. For the modeling of the bending behavior of the beam with conductivity, the kinematical assumptions of Bernoulli-Euler and a simplified form of the Telegraph equations are used. Applying d’Alembert’s principle, Gauss’ law of electrostatics and Kirchhoff’s voltage and current rules, the partial differential equations of motion are derived, describing the bending vibrations of the beam and the voltage distribution and current flow along the resistive electrodes. The theory is valid for applications that are used for actuation and for sensing. In the first case the voltage at a certain location on the electrodes is prescribed and the beam is deformed, whereas in the second case the structure is excited by a distributed external load and the voltage distribution is a result of the structural deformation. For a bimorph with constant width and constant material properties the beam is governed by two coupled partial differential equations for the elastic deformation and for the voltage distribution: the first one is an extension of the Bernoulli-Euler equation of an elastic beam, the second one is a diffusion equation for the voltage. The analytical results of the developed theory are validated by means of three-dimensional electromechanically coupled finite element simulations with ANSYS 11.0. Different mechanical and electrical boundary conditions and resistances of the electrodes are considered in the numerical case study. Eigenfrequencies are compared and the frequency responses of the mechanical and electrical quantities show a good agreement between the proposed beam theory and FE results.

  2. Analytical comparison of a US generic enoxaparin with the originator product: The focus on comparative assessment of antithrombin-binding components.

    PubMed

    Mourier, Pierre A J; Herman, Fréderic; Sizun, Philippe; Viskov, Christian

    2016-09-10

    Enoxaparin sodium, a low-molecular-weight heparin (LMWH) prepared from porcine intestinal heparin, is widely used for the prevention and treatment of venous thromboembolism. The antithrombotic activity of heparin is mediated mainly through its activation of antithrombin (AT) and subsequent inhibition of coagulation factors. Heparin is a complex heteropolymer and the sulfation pattern of its alternating uronic acid and glucosamine sugar units is a major factor influencing its biological activity. The manufacturing process itself is associated with the introduction of exogenous microheterogeneities that may further affect its biological efficacy. This is important since enoxaparin is prepared by depolymerizing the heparin with the aim of optimizing its biological activity and safety. Changes during its manufacture could thus affect its biological activity and safety. The current study was performed to assess potential differences between the originator enoxaparin and a new generic enoxaparin commercialized by Teva. Heparinase digestion, AT affinity chromatography, gel permeation chromatography, anion exchange chromatography, and nuclear magnetic resonance methodologies were used. The results indicated differences in oligosaccharides related to the cleavage selectivity around the heparin AT-binding sequences of the Teva Enoxaparin Sodium Injection, USP and the originator Sanofi enoxaparin. These differences influence the strength of the AT-binding affinity of the individual oligosaccharides, their ability to activate AT and, therefore, the inhibitory potency on the proteases of the coagulation cascade. This study, together with other published analytical reports, describes specific compositional differences between generics and originator LWMHs. However, it is yet to be established whether such variations might have any clinical relevance. Copyright © 2016 The Author(s). Published by Elsevier B.V. All rights reserved.

  3. Enabling direct nanoscale observations of biological reactions with dynamic TEM

    SciTech Connect

    Evans, James E.; Browning, Nigel D.

    2013-02-18

    Biological processes can occur over a wide range of spatial and temporal scales; from femtoseconds to hours and from angstroms to meters. Although no single experimental method can fully cover this entire phase space, many new biological insights can be expected from a better understanding of the processes that occur on the very fast timescales and very small length scales. In this regard, new instruments that use fast x-ray or electron pulses are now available that are expected to reveal new mechanistic insights for macromolecular protein dynamics. To ensure that any observed conformational change is physiologically relevant and not constrained by three-dimensional crystal packing, it would be preferable for experiments to utilize smaller protein samples such as single particles or two-dimensional crystals that mimic the target protein’s native environment. These samples aren’t typically amenable to x-ray analysis, but transmission electron microscopy has successfully imaged such sample geometries for over 40 years and permits data acquisition using both direct imaging and diffraction modes. While conventional transmission electron microscopes (TEM) have only visualized biological samples with atomic resolution in an arrested or frozen state, the recent development of the dynamic TEM (DTEM) extends electron microscopy capabilities into dynamics. A new 2nd generation DTEM that is currently being constructed has the potential to observe live biological processes with unprecedented spatiotemporal resolution by using pulsed electron packets to probe the sample on the micro- and nanosecond timescale. In addition to the enhanced temporal resolution, the DTEM also operates in the pump-probe regime that can permit visualizing reactions propagating in real-time. This article reviews the experimental parameters necessary for coupling DTEM with in situ liquid microscopy to allow direct imaging of protein conformational dynamics in a fully hydrated environment.

  4. Enabling direct nanoscale observations of biological reactions with dynamic TEM

    PubMed Central

    Evans, James E.; Browning, Nigel D.

    2013-01-01

    Biological processes occur on a wide range of spatial and temporal scales: from femtoseconds to hours and from angstroms to meters. Many new biological insights can be expected from a better understanding of the processes that occur on these very fast and very small scales. In this regard, new instruments that use fast X-ray or electron pulses are expected to reveal novel mechanistic details for macromolecular protein dynamics. To ensure that any observed conformational change is physiologically relevant and not constrained by 3D crystal packing, it would be preferable for experiments to utilize small protein samples such as single particles or 2D crystals that mimic the target protein's native environment. These samples are not typically amenable to X-ray analysis, but transmission electron microscopy has imaged such sample geometries for over 40 years using both direct imaging and diffraction modes. While conventional transmission electron microscopes (TEM) have visualized biological samples with atomic resolution in an arrested or frozen state, the recent development of the dynamic TEM (DTEM) extends electron microscopy into a dynamic regime using pump-probe imaging. A new second-generation DTEM, which is currently being constructed, has the potential to observe live biological processes with unprecedented spatiotemporal resolution by using pulsed electron packets to probe the sample on micro- and nanosecond timescales. This article reviews the experimental parameters necessary for coupling DTEM with in situ liquid microscopy to enable direct imaging of protein conformational dynamics in a fully hydrated environment and visualize reactions propagating in real time. PMID:23315566

  5. Visualization of Colloidal Nanocrystal Formation and Electrode-Electrolyte Interfaces in Liquids Using TEM.

    PubMed

    Zeng, Zhiyuan; Zheng, Wenjing; Zheng, Haimei

    2017-08-15

    Transmission electron microscopy (TEM) has become a powerful analytical tool for addressing unique scientific problems in chemical sciences as well as in materials sciences and other disciplines. There has been a lot of recent interest in the development and applications of liquid phase environmental TEM. In this Account, we review the development and applications of liquid cell TEM for the study of dynamic phenomena at liquid-solid interfaces, focusing on two areas: (1) nucleation, growth, and self-assembly of colloidal nanocrystals and (2) electrode-electrolyte interfaces during charge and discharge processes. We highlight the achievements and progress that have been made in these two topical areas of our studies. For example, tracking single platinum particle growth trajectories revealed that two different pathways of growth, either by monomer attachment or coalescence between nanoparticles, led to the same particle size. With the improved spatial resolution and fast electron detection, we were able to trace individual facet development during platinum nanocube platinum nanocube growth. The results showed that different from the surface energy minimization rule prediction, the growth rates of all low-energy facets, such as {100}, {110}, and {111}, were similar. The {100} facets stopped growth early, and the continuous growth of the rest facets resulted in a nanocube. Density functional theory calculations showed that the amine ligands with low mobility on the {100} facets blocked the further growth of the facets. The effect of the ligand on nanoparticle shape evolution were further studied systematically using a Pt-Fe nanoparticle system by changing the oleylamine concentration. With 20%, 30%, or 50% oleylamine, Pt-Fe nanowires or nanoparticles with different morphologies and stabilities were achieved. Real-time imaging of nanoparticles in solution also enabled the study of interactions between nanoparticles during self-assembly. We further compared the study of

  6. Comprehensive analysis of TEM methods for LiFePO4/FePO4 phase mapping: spectroscopic techniques (EFTEM, STEM-EELS) and STEM diffraction techniques (ACOM-TEM).

    PubMed

    Mu, X; Kobler, A; Wang, D; Chakravadhanula, V S K; Schlabach, S; Szabó, D V; Norby, P; Kübel, C

    2016-11-01

    Transmission electron microscopy (TEM) has been used intensively in investigating battery materials, e.g. to obtain phase maps of partially (dis)charged (lithium) iron phosphate (LFP/FP), which is one of the most promising cathode material for next generation lithium ion (Li-ion) batteries. Due to the weak interaction between Li atoms and fast electrons, mapping of the Li distribution is not straightforward. In this work, we revisited the issue of TEM measurements of Li distribution maps for LFP/FP. Different TEM techniques, including spectroscopic techniques (energy filtered (EF)TEM in the energy range from low-loss to core-loss) and a STEM diffraction technique (automated crystal orientation mapping (ACOM)), were applied to map the lithiation of the same location in the same sample. This enabled a direct comparison of the results. The maps obtained by all methods showed excellent agreement with each other. Because of the strong difference in the imaging mechanisms, it proves the reliability of both the spectroscopic and STEM diffraction phase mapping. A comprehensive comparison of all methods is given in terms of information content, dose level, acquisition time and signal quality. The latter three are crucial for the design of in-situ experiments with beam sensitive Li-ion battery materials. Furthermore, we demonstrated the power of STEM diffraction (ACOM-STEM) providing additional crystallographic information, which can be analyzed to gain a deeper understanding of the LFP/FP interface properties such as statistical information on phase boundary orientation and misorientation between domains.

  7. Comparison between red-green-blue imaging and visible-near infrared reflectance as potential process analytical tools for monitoring syneresis.

    PubMed

    Mateo, M J; O'Callaghan, D J; O'Donnell, C P

    2010-05-01

    The current work focuses on the comparison of 2 on-line optical sensing systems; namely red-green-blue imaging and visible-near infrared reflectance, for monitoring syneresis during cheese manufacture. The experimental design consisted of 3 temperature treatments carried out in an 11-L cheese vat in triplicate. Both systems were shown to predict syneresis without significant differences in prediction accuracy. However, a single-wavelength near infrared model was the most parsimonious (standard error of prediction=4.35g/100g) for predicting syneresis. This technique was also the simplest in terms of parameters in the model (standard error of prediction=4.15g/100g with 2 parameters), when time after gel cutting and process parameters (temperature and cutting time) were included in the models. The study showed that either system could be employed to control syneresis in cheese manufacture and improve the control of moisture content in cheese. Copyright 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  8. Analytical framework for screening long-time and large-scale soil moisture variability and its comparison with GRACE satellite data

    NASA Astrophysics Data System (ADS)

    Verrot, Lucile; Destouni, Georgia

    2016-04-01

    Soil moisture is a central component of the hydrologic cycle and its spatiotemporal variability offers a great challenge in assessing large-scale hydrological processes. As this variability depends greatly on prevailing hydro-climate, along with soil texture and its primarily spatial heterogeneity, soil moisture may be relatively easily constrained by large-scale water balance consideration in time and knowledge of soil property distribution in space. We have developed a relatively simple soil moisture model that relies on explicit account of spatial soil hydraulics parameters and catchment-wise organized hydro-climatic data and their variation in time. The current state of field techniques does not allow the retrieval of large-scale soil moisture data for direct comparison with model results. However, the recent GRACE satellite data provides for the first time large-scale directly comparative of large-scale water storage variability. This study compares the developed soil moisture model's ability to reproduce main variability dynamics in long-term data series of unsaturated water content and groundwater table position at the catchment scale with GRACE data, for a set of large tropical catchments.

  9. Comparison of analytical procedures to estimate CH4 and N2O fluxes from a two-year ecosystem study in a constructed wetland system

    NASA Astrophysics Data System (ADS)

    Ramos, J., Jr.; Chapman, E. J.; Weller, N.; Susanto, P.; Childers, D. L.

    2014-12-01

    estimated only by linear regression. Our results highlight the importance of weather conditions, vegetation, and nutrient loading on GHG fluxes in a CWS. Finally, it is important to establish long-term ecosystem-wide studies and at the same time, maintain a constant evaluation of analytical methods available for calculating GHG flux estimates.

  10. An Analytical Comparison of the Opinions of Physicians Working in Emergency and Trauma Surgery Departments at Tabriz and Vienna Medical Universities Regarding Family Presence during Resuscitation

    PubMed Central

    Soleimanpour, Hassan; Behringer, Wilhelm; Tabrizi, Jafar Sadegh; Sarahrudi, Kambiz; Golzari, Samad E J; Hajdu, Stefan; Rasouli, Maryam; Nikakhtar, Mehdi; Mehdizadeh Esfanjani, Robab

    2015-01-01

    The present study evaluated the opinions of physicians working in the emergency and trauma surgery departments of Vienna Medical University, in Austria, and Tabriz Medical University, in Iran, regarding the presence of patients’ relatives during resuscitation. In a descriptive-analytical study, the data obtained from questionnaires that had been distributed randomly to 40 specialists and residents at each of the participating universities were analyzed. The questionnaire consisted of two sections aimed at capturing the participants’ demographic data, the participants’ opinions regarding their support for the family’s presence during resuscitation, and the multiple potential factors affecting the participants’ attitudes, including health beliefs, triggers that could facilitate the procedure, self-efficacy, intellectual norms, and perceived behavioral control. The questionnaire also included a direct question (Question 16) on whether the participants approved of family presence. Each question could be answered using a Likert-type scale. The results showed that the mean scores for Question 16 were 4.31 ± 0.64 and 3.57 ± 1.31 for participants at Vienna and Tabriz universities, respectively. Moreover, physicians at Vienna University disapproved of the presence of patients’ families during resuscitation to a higher extent than did those at Tabriz University (P = 0.018). Of the studied prognostic factors affecting the perspectives of Vienna Medical University’s physicians, health beliefs (P = 0.000; B = 1.146), triggers (P = 0.000; B = 1.050), and norms (P = 0.000; B = 0.714) were found to be significant. Moreover, of the studied prognostic factors affecting the perspectives of Tabriz Medical University’s physicians, health beliefs (P = 0.000; B = 0.875), triggers (P = 0.000; B = 1.11), self-efficacy (P = 0.001; B = 0.5), and perceived behavioral control (P = 0.03; B = 0.713) were significant. Most physicians at Vienna and Tabriz Medical universities

  11. Development, evaluation and comparison of two independent sampling and analytical methods for ortho-phthalaldehyde vapors and condensation aerosols in air† ‡

    PubMed Central

    2015-01-01

    Two independent sampling and analytical methods for ortho-phthalaldehyde (OPA) in air have been developed, evaluated and compared (1) a reagent-coated solid sorbent HPLC-UV method and (2) an impinger-fluorescence method. In the first method, air sampling is conducted at 1.0 L min−1 with a sampler containing 350 mg of silica gel coated with 1 mg of acidified 2,4-dinitrophenylhydrazine (DNPH). After sampling, excess DNPH in ethyl acetate is added to the sampler prior to storage for 68 hours. The OPA-DNPH derivative is eluted with 4.0 mL of dimethyl sulfoxide (DMSO) for measurement by HPLC with a UV detector set at 3S5 nm. The estimated detection limit is 0.016 µg per sample or 0.067 µg m−3 (0.012 ppb) for a 240 L air sample. Recoveries of vapor spikes at levels of 1.2 to 6.2 µg were 96 to 101%. Recoveries of spikes as mixtures of vapor and condensation aerosols were 97 to 100%. In the second method, air sampling is conducted at 1.0 L mm−1 with a midget impinger containing 10 mL of DMSO solution containing N-acetyl-l-cysteine and ethylenediamine. The fluorescence reading is taken 80 min after the completion of air sampling. Since the time of taking the fluorescence reading is critical, the reading is taken with a portable fluorometer. The estimated detection limit is 0.024 µg per sample or 0.1 µg m−3 (0.018 ppb) for a 240 L air sample. Recoveries of OPA vapor spikes at levels of 1.4 to 5.0 µg per sample were 97 to 105%. Recoveries of spikes as mixtures of vapors and condensation aerosols were 95 to 99%. The collection efficiency for a mixture of vapor and condensation aerosol was 99.4%. The two methods were compared side-by-side in a generation system constructed for producing controlled atmospheres of OPA vapor in air. Average air concentrations of OPA vapor found by both methods agreed within ±10%. PMID:26346658

  12. Predictive accuracy comparison of MELD and Child-Turcotte-Pugh scores for survival in patients underwent TIPS placement: a systematic meta-analytic review.

    PubMed

    Zhou, Chunze; Hou, Changlong; Cheng, Delei; Tang, Wenjing; Lv, Weifu

    2015-01-01

    Child-Turcotte-Pugh (CTP) and the model for end-stage liver disease (MELD) scores have been used commonly to predict the survival in the patients with liver diseases underwent transjugular intrahepatic portosystemic shunt (TIPS). However, a debate has continued for years whether CTP could be replaced by MELD score. We performed a systematic meta-analytic review to compare the prediction capability of both scores in survival among patients with TIPS. Retrospective cohort studies among patients with TIPS were published as of May 2013 were identified by systematically searching four electronic literature database, such as Ovid Medline, PubMed, EMBASE, and ISI Web of Science. The difference of standardized mean difference (SMD) of c-statistics for the predictive accuracy of 1-, 3-, 6-, and 12-month survival for both MELD and CP scores, defined as effect size (ES), was calculated for each individual study and then pooled across studies using standard meta-analyses with a random effects model. Publication bias was evaluated using funnel plots and Kendall's rank correlation tests. 174 researches articles or conference abstracts were searched and reviewed using the combination of relevant terms in the articles. Finally, 11 articles were defined as eligible studies to evaluate simultaneously the predictive accuracy of MELD and CTP scores. In the meta-analyses, MELD score was superior to CP score in predicting 3-month survival after TIPS (mean ES, 0.63; 95% confidence interval [CI], 0.13-1.14; P=0.01), but the predictive capability in 1-month, 6-month, and 12-month survival was not significant (1-month: mean ES, 0.79; 95% CI, -0.24-1.83; P=0.13; 6-month: mean ES, 0.46; 95% CI, -2.46-3.37; P=0.76; 12-month: mean ES, 0.36; 95% CI, -0.25-0.96; P=0.25). No enough evidence are confirmed so far that MELD score is better than CTP score to assess the overall prognosis after TIPS, especially long-term predictions, but 3-month predictive capability of MELD score significantly

  13. Comparison of a novel strategy for the detection and isolation of Salmonella in shell eggs with the Food and Drug Administration Bacteriological Analytical Manual method.

    PubMed

    Zhang, Guodong; Thau, Eve; Brown, Eric W; Hammack, Thomas S

    2013-12-01

    The current FDA Bacteriological Analytical Manual (BAM) method for the detection of Salmonella in eggs requires 2 wk to complete. The objective of this project was to improve the BAM method for the detection and isolation of Salmonella in whole shell eggs. A novel protocol, using 1,000 g of liquid eggs for direct preenrichment with 2 L of tryptic soy broth (TSB) followed by enrichment using Rappaport-Vassiliadis and Tetrathionate broths, was compared with the standard BAM method, which requires 96 h room temperature incubation of whole shell egg samples followed by preenrichment in TSB supplemented with FeSO4. Four Salmonella ser. Enteritidis (4 phage types) and one Salmonella ser. Heidelberg isolates were used in the study. Bulk inoculated pooled liquid eggs, weighing 52 or 56 kg (approximately 1,100 eggs) were used in each trial. Twenty 1,000-g test portions were withdrawn from the pooled eggs for both the alternative and the reference methods. Test portions were inoculated with Salmonella at 1 to 5 cfu/1,000 g eggs. Two replicates were performed for each isolate. In the 8 trials conducted with Salmonella ser. Enteritidis, the alternative method was significantly (P < 0.05) more productive than the reference method in 3 trials, and significantly (P < 0.05) less productive than the reference method in 1 trial. There were no significant (P < 0.05) differences between the 2 methods for the other 4 trials. For Salmonella ser. Heidelberg, combined data from 2 trials showed the alternative method was significantly (P < 0.05) more efficient than the BAM method. We have concluded that the alternative method, described herein, has the potential to replace the current BAM culture method for detection and isolation of Salmonella from shell eggs based on the following factors: 1) the alternative method is 4 d shorter than the reference method; 2) it uses regular TSB instead of the more complicated TSB supplemented with FeSO4; and 3) it was equivalent or superior to the

  14. Duplex Oxide Formation during Transient Oxidation of Cu-5%Ni(001) Investigated by In situ UHV-TEM and XPS

    SciTech Connect

    Yang, J.C.; Starr, D.; Kang, Y.; Luo, L.; Tong, X.; Zhou, G.

    2012-05-20

    The transient oxidation stage of a model metal alloy thin film was characterized with in situ ultra-high vacuum (UHV) transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and analytic high-resolution TEM. We observed the formations of nanosized NiO and Cu{sub 2}O islands when Cu-5a5%Ni(100) was exposed to oxygen partial pressure, pO{sub 2} = 1 x 10{sup -4} Torr and various temperatures in situ. At 350 C epitaxial Cu{sub 2}O islands formed initially and then NiO islands appeared on the surface of the Cu{sub 2}O island, whereas at 750 C NiO appeared first. XPS and TEM was used to reveal a sequential formation of NiO and then Cu{sub 2}O islands at 550 C. The temperature-dependant oxide selection may be due to an increase of the diffusivity of Ni in Cu with increasing temperature.

  15. TEM-E1: a novel beta-lactamase conferring resistance to ceftazidime.

    PubMed

    Payne, D J; Marriott, M S; Amyes, S G

    1989-05-01

    A novel beta-lactamase, conferring resistance to ceftazidime, has been identified to be encoded by a 31 kb plasmid (pUK720) in a clinical E. coli strain isolated in Belgium. The beta-lactamase, new designated TEM-E1, has a pI of approximately 5.4 and lies in between the iso-electric focused bands of the beta-lactamases TEM-1 and TEM-7. The TEM-E1 beta-lactamase has a similar molecular weight of 22,000 to the TEM-1 and it is also inhibited by clavulanic acid. However, the TEM-E1 enzyme differs from TEM-1 by its low rates and efficiency of hydrolysis for ceftazidime and cefotaxime, TEM-E1 has similar efficiency of hydrolysis values for ceftazidime and cefotaxime, but only confers resistance to ceftazidime.

  16. Analytical Relativity of Black Holes

    NASA Astrophysics Data System (ADS)

    Damour, Thibault

    The successful detection and analysis of gravitational wave (GW) signals from coalescing binary black holes necessitates the accurate prior knowledge of the form of the GW signals. This knowledge can be acquired through a synergy between Analytical Relativity (AR) methods and Numerical Relativity (NR) ones. We describe here the most promising AR formalism for describing the motion and radiation of coalescing binary black holes, the Effective One Body (EOB) method, and discuss its comparison with NR simulations.

  17. Comparison of sample types and analytical methods for the detection of highly campylobacter-colonized broiler flocks at different stages in the poultry meat production chain.

    PubMed

    Seliwiorstow, Tomasz; Duarte, Alexandra; Baré, Julie; Botteldoorn, Nadine; Dierick, Katelijne; Uyttendaele, Mieke; De Zutter, Lieven

    2015-05-01

    Exclusion of broiler batches, highly colonized with Campylobacter (>7.5 log10 colony-forming units/g), from the fresh poultry meat market might decrease the risk of human campylobacteriosis. The objective of this study was to compare different sample types (both at the farm and the slaughterhouse) and methods (direct culture, quantitative real-time polymerase chain reaction [qPCR], propidium monoazide [PMA]-qPCR) applied for the quantification of the Campylobacter colonization level. In addition, the applicability of the lateral flow-based immunoassay, Singlepath(®) Direct Campy Poultry test (Singlepath(®) test), was evaluated as a rapid method for the qualitative detection of Campylobacter in highly colonized broiler batches. Campylobacter counts differed significantly between sample types collected at farm level (cecal droppings, feces, boot swabs) and at slaughterhouse level (cecal content, fecal material from crates). Furthermore, comparison of Campylobacter counts obtained by different methods (direct culture, qPCR, PMA-qPCR) in cecal droppings revealed significant differences, although this was not observed for cecal-content samples. Evaluation of the Singlepath(®) test on cecal droppings and cecal-content samples revealed an acceptable level of sensitivity and specificity. In conclusion, cecal droppings and cecal content are proposed as the most representative sample types for quantification of Campylobacter colonization level of broilers at farm and slaughterhouse, respectively. Direct culture and qPCR are equally sensitive for quantification of Campylobacter in fresh cecal-content samples. PMA treatment before qPCR inhibits the signal from dead Campylobacter cells. Consequently, when samples are extensively stored and/or transported, qPCR is preferred to direct culture and PMA-qPCR. Furthermore, the Singlepath(®) test offers a convenient alternative method for rapid detection of Campylobacter in highly colonized broiler batches.

  18. A meta-analytical comparison of atenolol with angiotensin-converting enzyme inhibitors on arterial stiffness, peripheral blood pressure and heart rate in hypertensive patients.

    PubMed

    Xie, Hong; Luo, Gaoqing; Zheng, Yong; Peng, Feng; Xie, Liangdi

    2017-01-01

    This meta-analysis of randomized parallel controlled trials was designed to compare the efficacy of atenolol with angiotensin-converting enzyme inhibitors (ACEIs) in changing pulse wave velocity (PWV), peripheral blood pressure and heart rate (HR) among patients with essential hypertension. This study was conducted according to the PRISMA guideline. Data collection was independently completed by two investigators. Statistical analyses were completed by Stata software (v12.0). Eight clinical trials were meta-analyzed in this study. Overall changes in PWV (weighted mean difference or WMD = 0.068, 95% confidence interval or CI: -0.487 to -0.623, P = 0.811) and peripheral systolic blood pressure (PSBP) (WMD = -1.281 mmHg, 95% CI: -6.936 to 4.375, P = 0.657) did not differ significantly between atenolol and ACEIs treatment. Relative to ACEIs, atenolol had a more favorable impact on peripheral diastolic blood pressure (PDBP) (WMD = -1.912 mmHg, 95% CI: -3.732 to -0.091, P = 0.040) and HR (WMD = -9.23 bpm, 95% CI: -12.53 to -5.93, P < 0.001). In stratified analyses, particularly by follow-up period, atenolol was observed to be superior over ACEIs within early 3-month treatment in PSBP (WMD = -4.097 mmHg, 95% CI: -6.589 to -1.605, P = 0.001), PDBP (WMD = -6.802 mmHg, 95% CI: -8.517 to -5.087, P < 0.001) and HR (WMD = -14.242 bpm, 95% CI: -16.427 to -12.058, P = 0.028), without heterogeneity (I(2) = 0.0%). There were low probabilities of publication bias for all comparisons. Our findings demonstrate that atenolol and ACEIs were equally effective in reducing PWV and PSBP, while atenolol was superior over ACEIs in improving PDBP and HR, especially within short-term treatment.

  19. Determination of the content of rosmarinic acid by HPLC and analytical comparison of volatile constituents by GC-MS in different parts of Perilla frutescens (L.) Britt.

    PubMed

    Liu, Jing; Wan, Yuklam; Zhao, Zhongzhen; Chen, Hubiao

    2013-04-01

    Perilla frutescens (L.) Britt. is not only an edible plant but also a traditional medicinal plant commonly used for treating common cold. It is widely cultivated in southern China. The anatomical parts of P. frutescens that are recorded as medicines in the Chinese material medica are: Perillae Caulis, Perillae Folium and Perillae Fructus, which are the dried stems, the dried leaves and the dried ripe fruits, respectively. Rosmarinic acid is one of major polyphenolic ingredients found in all three Perillae Caulis, Perillae Folium and Perillae Fructus. The characteristic volatile oil of P. frutescens is believed to be another essential composition of the herb, giving its wide range of use. A simple, rapid and accurate HPLC-DAD method was set up, suitable for the assay of rosmarinic acid in Perillae Fructus, Perillae Folium and Perillae Caulis. 12 batches of Perillae Caulis, 12 batches of Perillae Folium and 13 batches of Perillae Fructus from 8 different regions of mainland China and Hong Kong herbal markets were collected for evaluating the quality of P. frutescens. Results showed that Perillae Folium typically had the highest content of rosmarinic acid. Certain macroscopic characteristics were related to the concentration of rosmarinic acid. The volatile components were identified and compared in Perillae Fructus, Perillae Folium and Perillae Caulis by gas chromatography-mass spectrometry (GC-MS). Extracts were prepared by steam distillation. Twelve, seventeen and nine compounds were identified and accounted for 69.71%, 50.54% and 81.73% of all identified peak areas in Perillae Caulis, Perillae Folium and Perillae Fructus respectively. The identified components were analyzed for comparison of Perillae Caulis, Perillae Folium and Perillae Fructus more effectively. This work provides a means by which samples of various parts of P. frutescens can be evaluated in terms of their pharmacologically active components. It should be of value in the efficient exploitation of

  20. TransAnal Minimally Invasive Surgery (TAMIS) with SILS™ port versus Transanal Endoscopic Microsurgery (TEM): a comparative experimental study.

    PubMed

    Rimonda, Roberto; Arezzo, Alberto; Arolfo, Simone; Salvai, Alessandro; Morino, Mario

    2013-10-01

    TransAnal Minimally Invasive Surgery (TAMIS) has been proposed as an alternative to Transanal Endoscopic Microsurgery (TEM) for resection of benign polyps and early cancers of rectum. Since clinical application has begun in the absence of any experimental validation, we assessed its feasibility and efficacy ex vivo in a pilot study. In a dedicated trainer box for transanal procedures, 10 surgeons with no experience in transanal surgery were asked to perform a dissection/suture task using both TAMIS and TEM in randomly allocated order. Surgeons were asked to dissect two identically drawn lesions of ~3 cm in larger diameter. Precision of dissection was assessed using a quantitative photographic method, while the time needed for dissection and suturing was considered a measure of quantitative evaluation. Each participant expressed a subjective opinion regarding difficulty with dissection, difficulty with suturing, vision quality, and conflict between instruments on a scale from 1 to 5. No difference was observed between the two techniques regarding the accuracy of dissection as the margin was interrupted along 4.1 % of the circumference in the TEM group compared with 2.48 % in the SILS group (P = 0.271). Dissection and suturing were significantly quicker in the TEM group [04:30 vs. 06:35 min (P = 0.049) and 14:34 versus 19:18 min (P = 0.003)]. In three cases in the SILS group, completing the suture was not considered possible, and the procedures were terminated by TEM. Subjective evaluation revealed a better appreciation of TEM in all proposed comparisons: dissection (2.6 vs. 3.5, P = 0.004), suturing difficulty (3.1 vs. 4.6, P < 0.001), quality of vision (2.3 vs. 2.8, P = 0.18), and instrument conflicts (3.1 vs. 4.0, P = 0.054). In the ex vivo setting, both techniques were comparable for achieving a good dissection, although TAMIS failed to prove effective in suturing the rectal wall. Moreover, TEM was significantly quicker despite the small groups

  1. Comparison and validation of Logistic Regression and Analytic Hierarchy Process models of landslide susceptibility in monoclinic regions. A case study in Moldavian Plateau, N-E Romania

    NASA Astrophysics Data System (ADS)

    Ciprian Margarint, Mihai; Niculita, Mihai

    2014-05-01

    , were chosen. As measures of validation for the fit of the model, we have used AUROC value, cross-validation estimates of predictive accuracy and the percent of mapping units correctly classified. For the same sample, the Analytic Hierarchy Process (AHP) approach was applied for landslide susceptibility assessment, using 7 predictors (slope angle, slope aspect, plan and profile curvature, distance to river network, distance to roads, and land use). The validation of the LR and AHP approaches was assessed using the inventories with active landslides for 1978 and 2010 situations. For estimating the level of replicability of the results, an extra-domain sample it was used, situated in the vicinity of the first area, having the same size (90 km2). For the extra-domain area, the same weights obtained for LR approach and the same predictors and weights assigned for the AHP approaches, were used in the modelling. The extra-domain resulted AUROC values are closed with the ones from the original area, but there is small variance, a decrease by 0.07% for LR and by 0.05% for AHP approach. These results allow us to consider that applying both quantitative (LR) and semi-quantitative (AHP) methods for landslide susceptibility assessment at medium scale, in regions with high level of geomorphologic uniformity, such as monoclinic areas, could be applied with good results. Using these two methods for an extra-domain area, we can assess the sensitivity of the input covariates. Also, two maps showing the differences between the two models of landslide susceptibility, both for the first and for the extra-domain sample, were carried out and interpreted.

  2. Quantitative chemical analysis of ocular melanosomes in the TEM.

    PubMed

    Eibl, O; Schultheiss, S; Blitgen-Heinecke, P; Schraermeyer, U

    2006-01-01

    Melanosomes in retinal tissues of a human, monkey and rat were analyzed by EDX in the TEM. Samples were prepared by ultramicrotomy at different thicknesses. The material was mounted on Al grids and samples were analyzed in a Zeiss 912 TEM equipped with an Omega filter and EDX detector with ultrathin window. Melanosomes consist of C and O as main components, mole fractions are about 90 and 3-10 at.%, respectively, and small mole fraction ratios, between 2 and 0.1 at.%, of Na, Mg, K, Si, P, S, Cl, Ca. All elements were measured quantitatively by standardless EDX with high precision. Mole fractions of transition metals Fe, Cu and Zn were also measured. For Fe a mole fraction ratio of less than 0.1at.% was found and gives the melanin its paramagnetic properties. Its mole fraction is however close to or below the minimum detectable mass fraction of the used equipment. Only in the human eye and only in the retinal pigment epitelium (rpe) the mole fractions of Zn (0.1 at.% or 5000 microg/g) and Cu were clearly beyond the minimum detectable mass fraction. In the rat and monkey eye the mole fraction of Zn was at or below the minimum detectable mass fraction and could not be measured quantitatively. The obtained results yielded the chemical composition of the melanosomes in the choroidal tissue and the retinal pigment epitelium (rpe) of the three different species. The results of the chemical analysis are discussed by mole fraction correlation diagrams. Similarities and differences between the different species are outlined. Correlation behavior was found to hold over species, e.g. the Ca-O correlation. It indicates that Ca is bound to oxygen rich sites in the melanin. These are the first quantitative analyses of melanosomes by EDX reported so far. The quantitative chemical analysis should open a deeper understanding of the metabolic processes in the eye that are of central importance for the understanding of a large number of eye-related diseases. The chemical analysis also

  3. Analytics for Education

    ERIC Educational Resources Information Center

    MacNeill, Sheila; Campbell, Lorna M.; Hawksey, Martin

    2014-01-01

    This article presents an overview of the development and use of analytics in the context of education. Using Buckingham Shum's three levels of analytics, the authors present a critical analysis of current developments in the domain of learning analytics, and contrast the potential value of analytics research and development with real world…

  4. Let's Talk... Analytics

    ERIC Educational Resources Information Center

    Oblinger, Diana G.

    2012-01-01

    Talk about analytics seems to be everywhere. Everyone is talking about analytics. Yet even with all the talk, many in higher education have questions about--and objections to--using analytics in colleges and universities. In this article, the author explores the use of analytics in, and all around, higher education. (Contains 1 note.)

  5. TEM study of impurity segregations in beryllium pebbles

    NASA Astrophysics Data System (ADS)

    Klimenkov, M.; Chakin, V.; Moeslang, A.; Rolli, R.

    2014-12-01

    Beryllium is planned to be used as a neutron multiplier in the Helium-cooled Pebble Bed European concept of a breeding blanket of demonstration power reactor DEMO. In order to evaluate the irradiation performance, individual pebbles and constrained pebble beds were neutron-irradiated at temperatures typical of fusion blankets. Beryllium pebbles 1 mm in diameter produced by the rotating electrode method were subjected to a TEM study before and after irradiation at High Flux Reactor, Petten, Netherlands at 861 K. The grain size varied in a wide range from sub-micron size up to several tens of micrometers, which indicated formation bimodal grain size distribution. Based on the application of combined electron energy loss spectroscopy and energy dispersive X-ray spectroscopy methods, we suggest that impurity precipitates play an important role in controlling the mechanical properties of beryllium. The impurity elements were present in beryllium at a sub-percent concentration form beryllide particles of a complex (Fe/Al/Mn/Cr)B composition. These particles are often ordered along dislocations lines, forming several micron-long chains. It can be suggested that fracture surfaces often extended along these chains in irradiated material.

  6. Quantitative TEM analysis of the barn owl basilar papilla.

    PubMed

    Fischer, F P

    1994-02-01

    The morphology of the barn owl's basilar papilla was quantitatively analyzed using TEM methods. The hair-cell (HC) parameters studied in the basal two-thirds of the papilla are remarkably constant. This large portion represents an extended high frequency area, or fovea [Köppl et al. (1993) J. Comp. Physiol. A 171, 695-704]. In the apical third of the papilla, in contrast, these parameters change regularly, as they do in other avian species. The HC in the most neural position remain morphologically more similar along the entire length of the papilla than do neighbouring cell rows. In the behaviourally most important frequency range (4-9 kHz), the afferent innervation of these neural HC is very dense and is reminiscent of the situation in mammals. Differences in HC morphology also indicate a specialization of the extreme apex of the papilla in the barn owl. Avian HC morphology is not correlated with a specific place along the basilar papilla but rather with the best frequency. Based on the body of recent quantitative morphological data on avian HC structure, a modified definition of HC types in birds is suggested (while keeping introduced terms): THC (tall hair cells) are defined as all those HC with afferent (and normally also efferent) innervation. SHC (short hair cells) are the (more specialized) HC without afferent innervation; obviously their function is restricted to the papilla itself.

  7. TEM in situ lithiation of tin nanoneedles for battery applications

    SciTech Connect

    Janish, Matthew T.; Mackay, David T.; Liu, Yang; Jungjohann, Katherine L.; Carter, C. Barry; Norton, M. Grant

    2015-08-12

    Materials such as tin (Sn) and silicon that alloy with lithium (Li) have attracted renewed interest as anode materials in Li-ion batteries. Although their superior capacity to graphite and other intercalation materials has been known for decades, their mechanical instability due to extreme volume changes during cycling has traditionally limited their commercial viability. This limitation is changing as processes emerge that produce nanostructured electrodes. The nanostructures can accommodate the repeated expansion and contraction as Li is inserted and removed without failing mechanically. Recently, one such nano-manufacturing process, which is capable of depositing coatings of Sn “nanoneedles” at low temperature with no template and at industrial scales, has been described. The present work is concerned with observations of the lithiation and delithiation behavior of these Sn nanoneedles during in situ experiments in the transmission electron microscope, along with a brief review of how in situ TEM experiments have been used to study the lithiation of Li-alloying materials. Individual needles are successfully lithiated and delithiated in solid-state half-cells against a Li-metal counter-electrode. Furthermore the microstructural evolution of the needles is discussed, including the transformation of one needle from single-crystal Sn to polycrystalline Sn–Li and back to single-crystal Sn.

  8. TEM in situ lithiation of tin nanoneedles for battery applications

    DOE PAGES

    Janish, Matthew T.; Mackay, David T.; Liu, Yang; ...

    2015-08-12

    Materials such as tin (Sn) and silicon that alloy with lithium (Li) have attracted renewed interest as anode materials in Li-ion batteries. Although their superior capacity to graphite and other intercalation materials has been known for decades, their mechanical instability due to extreme volume changes during cycling has traditionally limited their commercial viability. This limitation is changing as processes emerge that produce nanostructured electrodes. The nanostructures can accommodate the repeated expansion and contraction as Li is inserted and removed without failing mechanically. Recently, one such nano-manufacturing process, which is capable of depositing coatings of Sn “nanoneedles” at low temperature withmore » no template and at industrial scales, has been described. The present work is concerned with observations of the lithiation and delithiation behavior of these Sn nanoneedles during in situ experiments in the transmission electron microscope, along with a brief review of how in situ TEM experiments have been used to study the lithiation of Li-alloying materials. Individual needles are successfully lithiated and delithiated in solid-state half-cells against a Li-metal counter-electrode. Furthermore the microstructural evolution of the needles is discussed, including the transformation of one needle from single-crystal Sn to polycrystalline Sn–Li and back to single-crystal Sn.« less

  9. Advanced TEM Sample Preparation Using Low Energy (Preprint)

    DTIC Science & Technology

    2007-11-01

    1.69 C - O 288.95 2.00 C - O - C (=O) - C O 1s 47.99 531.01 2.33 Al2O3 • 0.30 Ga2O3 • 2.68 H2O 532.55 45.66 SiO2 • 0.35 H2O, C - O - C (=O) - C, C - O...Si 2p 24.43 99.09 7.39 Si 103.29 17.04 SiO2 • 0.35 H2O Al 2p 0.67 72.68 0.29 Al 75.59 0.71 Al2O3 • 0.30 Ga2O3 • 2.68 H2O Ga 3d 0.50 18.72 0.29 Ga...21.22 0.21 Al2O3 • 0.30 Ga2O3 • 2.68 H2O Results of subsequent imaging and TEM-EDS analyses before and after low energy Ar milling are shown below

  10. Aquifer characterisation in East Timor, with ground TEM

    NASA Astrophysics Data System (ADS)

    Ley-Cooper, A.

    2011-12-01

    An assessment of Climate Change Impacts on Groundwater Resources in East Timor led by Geosciences Australia is aimed at assisting East Timor's government to better understand and manage their groundwater resources. Form the current known information most aquifers in Timor-Leste are recharged by rainfall during the wet season. There is a concern that without a regular recharge, the stored groundwater capacity will decrease. Timor's population increase has caused a higher demand for groundwater which is currently been met by regulated pumping bores which are taped into deep aquifers, plus the sprouting of unregulated spear point bores in the shallow aquifers . Both groundwater recharge and the aquifers morphology need to be better understood in order to ensure supply and so groundwater can be managed for the future. Current weather patterns are expected to change and this could cause longer periods of drought or more intense rainfall, which in turn, would affect the availability and quality of groundwater. Salt water intrusions pose a threat on the low-lying aquifers as sea level rises. Australia's CSIRO has undertaken a series hydrogeophysical investigations employing ground TEM to assist in the characterisation of three aquifers near Dili, Timor Leste's capital. Interpreting ground water chemistry and dating; jointly with EM data has enhanced the understanding of the aquifers architecture, groundwater quality and helped identify potential risks of seawater intrusions.

  11. Microscopic measurement of the degree of mixing for nanoparticles in polymer nanocomposites by TEM images.

    PubMed

    Kim, Dongsik; Lee, Jun S; Barry, Carol M F; Mead, Joey L

    2007-06-01

    For polymer nanocomposites, the small size of the fillers makes it difficult to analyze the degree of mixing quantitatively and often requires direct assessment via transmission electron microscopy (TEM). To date, qualitative comparisons and indirect measurements of the degree of mixing by measurement of certain properties are the most common methods. Better methods to quantitatively characterize the degree of mixing in nanocomposites would aid in studies investigating the effect of process conditions on the mixing behavior. Alumina/PET nanocomposites of identical composition, but with different degrees of mixing were prepared using a batch mixer. For evaluation of the degree of mixing with respect to both dispersion and distribution, three different techniques were applied and compared. TEM particle density was useful for dispersion, but did not adequately characterize distribution, while the Morisita's index gave poor results due to a wide range of effective particle sizes. Both methods ranked the samples differently compared to direct visual observation. In contrast, the skewness calculated by the quadrat method produced results consistent with visual rankings, and was found to be most effective in comparing and quantifying the degree of mixing. Although the quadrat method requires proper selection of quadrat size for a particular particle concentration, the skewness from the quadrat method was found to be most suitable as a standard index for the degree of mixing in nanocomposites. The usefulness of the quadrat method was verified using a second set of nanocomposites prepared by a twin screw extruder showing the potential for application of this technique for process development and quality control in commercial nanomanufacturing processes. Copyright (c) 2007 Wiley-Liss, Inc.

  12. Limited interaction of a self-adhesive flowable composite with dentin/enamel characterized by TEM.

    PubMed

    Mine, Atsushi; De Munck, Jan; Van Ende, Annelies; Poitevin, André; Matsumoto, Mariko; Yoshida, Yasuhiro; Kuboki, Takuo; Van Landuyt, Kirsten L; Yatani, Hirofumi; Van Meerbeek, Bart

    2017-02-01

    A new category of composite which does not require any acid etching or bonding protocol prior to application has been introduced. The purpose of this study was to characterize the interfacial ultra-structure at enamel and dentin surfaces by means of transmission electron microscopy (TEM). Non-carious human third molars were randomly divided into 6 groups (bur-cut dentin, SiC-ground dentin, fractured dentin, bur-cut enamel, SiC-ground enamel, and un-cut enamel). After preparation of the respective surfaces, the self-adhesive flowable composite (Vertise Flow, Kerr) was applied. Non-demineralized/demineralized and non-stained/stained sections of 70-90nm were prepared following common TEM-specimen processing procedures. Additional specimens were immersed in an ammoniacal silver nitrate solution. The composite-dentin interface was free of voids and no de-bonding occurred during specimen preparation. For bur-cut and SiC-ground dentin, no surface demineralization was observed and the smear contained residual hydroxyapatite. On fractured dentin (i.e. without smear interference), a very thin interaction area of 100-200nm without apparent signs of surface demineralization was seen. When the composite was bonded to enamel, a distinct separation between the self-adhesive composite and enamel was present in all three groups. A tight interaction, yet without distinct dissolution of hydroxyapatite, could only be seen in some regions at bur-cut enamel where smear was absent or sparse. Silver nitrate infiltration was associated with the presence of smear. The self-adhesive composite showed limited interaction with smear-covered substrates and aprismatic enamel, which explains its inferior diminished bonding capacity in comparison with current adhesives. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  13. Characterization of Pebax angioplasty balloon surfaces with AFM, SEM, TEM, and SAXS.

    PubMed

    Warner, Jacob A; Forsyth, Bruce; Zhou, Fang; Myers, Jason; Frethem, Chris; Haugstad, Greg

    2016-04-01

    In the medical device industry, angioplasty balloons have been widely used in the less invasive treatment of heart disease by expanding and relieving clogged structures in various arterial segments. However, new applications using thin coatings on the balloon surface have been explored to enhance therapeutic value in the delivery of pharmaceuticals (drug-elution) or control thermal energy output (RF ablation). In this study, angioplasty balloon materials comprised of poly(ether-block-amide) (Pebax) were investigated via atomic force microscopy (AFM), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and small-angle X-ray scattering (SAXS) to characterize physical properties at the balloon surface that may affect coating adhesion. The soft segment of this Pebax 1074 material is polyethylene oxide (PEO) and the hard segment is nylon-12. The morphology of the hard segments of this block co-polymer are found via AFM stiffness measurements to be (40 ± 20) nm by (300 ± 150) nm and are oriented parallel to the surface of the balloon. SAXS measurements found the lamellar spacing to be (18.5 ± 0.5) nm, and demonstrate a preferential orientation in agreement with TEM and AFM measurements. Fixation of this balloon in resin, followed by cryo-sectioning is shown to provide a novel manner in which to investigate surface characteristics on the balloon such as material or coating thickness as well as uniformity in comparison to the bulk structure. These outputs were deemed critical to improve overall balloon processing such as molding and surface treatment options for robust designs toward better procedural outcomes targeting new therapeutic areas.

  14. High-resolution methane emission estimates using surface measurements and the InTEM inversion system.

    NASA Astrophysics Data System (ADS)

    Connors, Sarah; Manning, Alistair; Robinson, Andrew; Riddick, Stuart; Forster, Grant; Oram, Dave; O'Doherty, Simon; Harris, Neil

    2015-04-01

    High quality GHG emission estimates will be required to successfully tackle climate change. There is a growing need for comparisons between emission estimates produced using bottom-up and top-down techniques at high spatial resolution. Here, a top-down inversion approach combining multi-year atmospheric measurements and an inversion model, InTEM, was used to estimate methane emissions for a region in the South East of the UK (~100 x 150 km). We present results covering a 2-year period (July 2012 - July 2014) in which atmospheric methane concentrations were recorded at 1 - 2 minute time-steps at four locations within the region of interest. Precise measurements were obtained using gas chromatography with flame ionisation detection (GC-FID) for all sites except one, which used a PICARRO Cavity Ring-Down Spectrometer (CRDS). These observations, along with the UK Met Office's Lagrangian particle dispersion model, NAME, were used within InTEM to produce the methane emission fields. We present results from both Bayesian and non-prior based inversion analysis at varying spatial resolutions, for annual, seasonal and monthly time frames. These results are compared with the UK National Atmospheric Emissions Inventory (NAEI) which is compiled using bottom-up methods and available at 1x1 km resolution. A thorough assessment of uncertainty is incorporated into this technique which is represented in the results. This project is part of the UK GAUGE campaign which aims to produce robust estimates of the UK GHG budget using new and existing measurement networks (e.g. the UK DECC GHG network) and modelling activities at a range of scales.

  15. An in situ heating TEM analysis method for an interface reaction.

    PubMed

    Tanigaki, Toshiaki; Ito, Katsuji; Nagakubo, Yasuhira; Asakawa, Takayuki; Kanemura, Takashi

    2009-10-01

    In order to analyze the thermal property of nano-sized materials, an in situ observation technique that allows highly sensitive energy dispersive x-ray spectroscopic (EDX) analyses and high-resolution in situ heating observation of precision specimens is required. A method for the in situ observation of the interface reaction using an analytical transmission electron microscopy (TEM) and a specimen-heating holder was developed. The specimen holder used in this study was a direct-heating type having a fine tungsten wire heater. For sensitive analyses including an EDX map of composition changes during the interface reaction, a space toward the EDX detector with a take-off angle of 20 degrees was made in the specimen holder. Samples were prepared by attaching a micro-sample directly to the heater using the focused ion beam (FIB) micro-sampling technique. It was confirmed that the sensitive EDX map and electron diffraction analyses were possible during the reaction, and that the resolution of this technique was of the order of 0.223 nm at 550 degrees C.

  16. TEM Study of Manganese Biosorption by Cyanobacterium Synechocystis 6803

    SciTech Connect

    Dohnalkova, Alice; Bilskis, Christina L.; Kennedy, David W.

    2006-09-01

    The capture of solar energy and its conversion into chemical energy in photosynthetic organisms involves a series of charge reactions across photosynthetic membranes. Oxygen is generated by a proton-electron coupling in photosystem II (PSII) during a water oxidation process where hydrogen is extracted from water terminally bound to a Mn4Ca1Clx inorganic cluster [1]. Manganese is, therefore, an essential catalytic element for photosynthetic growth in cyanobacteria and plants. Since bioavailability of this micronutrient largely depends on the Mn concentration in natural environments, cells have to manage its uptake in order to endure Mn fluctuations. Previous studies have shown that metal biosorption in cyanobacteria can occur by passive adsorption to their outer membrane (pool A), and by metabolically mediated internal uptake [2]. The fresh water cyanobacterium Synechocystis 6803 has been widely used as a model organism for studying photosynthetic processes. This Gram-negative organism has an intricate architecture of internal thylakoid membranes where photosynthetic electron transfer takes place. Here we report on the spatial distribution of Mn biosorbed by cells in both external pool A and intracellular pool B, as observed and analyzed by methods of TEM. The Synechocystis 6803 cells were cultured in BG11 medium at 30 C with continuous irradiance and constant air bubbling. To determine the influence of solid or liquid Mn substrate and its oxidation state on the cell biosorption ability, cells were exposed to two Mn substrates: 1mM solution of MnCl2, and 0.5mM suspension of nanocrystalline MnO2. Cells were incubated with the respective Mn solutions for 48 hours, harvested, and processed using a modified protocol for plastic embedding of bacterial samples containing minerals that was developed in our laboratory [3]. In order to preserve the fragile redox conditions within the cells, all the common heavy metal-based fixatives and stains were omitted, resulting in

  17. The transfer of analytical procedures.

    PubMed

    Ermer, J; Limberger, M; Lis, K; Wätzig, H

    2013-11-01

    Analytical method transfers are certainly among the most discussed topics in the GMP regulated sector. However, they are surprisingly little regulated in detail. General information is provided by USP, WHO, and ISPE in particular. Most recently, the EU emphasized the importance of analytical transfer by including it in their draft of the revised GMP Guideline. In this article, an overview and comparison of these guidelines is provided. The key to success for method transfers is the excellent communication between sending and receiving unit. In order to facilitate this communication, procedures, flow charts and checklists for responsibilities, success factors, transfer categories, the transfer plan and report, strategies in case of failed transfers, tables with acceptance limits are provided here, together with a comprehensive glossary. Potential pitfalls are described such that they can be avoided. In order to assure an efficient and sustainable transfer of analytical procedures, a practically relevant and scientifically sound evaluation with corresponding acceptance criteria is crucial. Various strategies and statistical tools such as significance tests, absolute acceptance criteria, and equivalence tests are thoroughly descibed and compared in detail giving examples. Significance tests should be avoided. The success criterion is not statistical significance, but rather analytical relevance. Depending on a risk assessment of the analytical procedure in question, statistical equivalence tests are recommended, because they include both, a practically relevant acceptance limit and a direct control of the statistical risks. However, for lower risk procedures, a simple comparison of the transfer performance parameters to absolute limits is also regarded as sufficient. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Three Dimensional TEM Forward Modeling Using FDTD Accelerated by GPU

    NASA Astrophysics Data System (ADS)

    Li, Z.; Huang, Q.

    2015-12-01

    Three dimensional inversion of transient electromagnetic (TEM) data is still challenging. The inversion speed mostly depends on the forward modeling. Finite-difference time-domain (FDTD) method is one of the popular forward modeling scheme. In an explicit type, which is based on the Du Fort-Frankel scheme, the time step is under the constraint of quasi-static approximation. Often an upward-continuation boundary condition (UCBC) is applied on the earth-air surface to avoid time stepping in the model air. However, UCBC is not suitable for models with topography and has a low parallel efficiency. Modeling without UCBC may cause a much smaller time step because of the resistive attribute of the air and the quasi-static constraint, which may also low the efficiency greatly. Our recent research shows that the time step in the model air is not needed to be constrained by the quasi-static approximation, which can let the time step without UCBC much closer to that with UCBC. The parallel performance of FDTD is then largely released. On a computer with a 4-core CPU, this newly developed method is obviously faster than the method using UCBC. Besides, without UCBC, this method can be easily accelerated by Graphics Processing Unit (GPU). On a computer with a CPU of 4790k@4.4GHz and a GPU of GTX 970, the speed accelerated by CUDA is almost 10 times of that using CPU only. For a model with a grid size of 140×140×130, if the conductivity of the model earth is 0.02S/m, and the minimal space interval is 15m, it takes only 80 seconds to evolve the field from excitation to 0.032s.

  19. In-situ TEM characterization of Copper Growth

    NASA Astrophysics Data System (ADS)

    Shelberg, Daniel T.

    In-situ liquid experiments in the transmission electron microscope (TEM) allow dynamic phenomena to be imaged at the nanoscale. This opens the opportunity to view electrochemical depositions at the nano scale in real time. However, there are a number of issues regarding in situ imaging that prevent a straightforward approach. This thesis addresses two issues regarding in-situ experiments; the fabrication of electron transparent windows and the nucleation of a metal from an electrolyte as a result of beam damage. Silicon chips that were 2.6mm x 2.6mm with 50mum x 50mum windows consisting of 50nm S3N 4 were fabricated with the goal of minimizing fabrication complexity at a cost significantly below commercial prices. These silicon nitride windows were used to sandwich a small volume of CuSO4 solution and observe copper nucleation as a result of the radiolysis damage of water due to the electron beam. Scanning transmission electron microscopy (STEM) was used to image growth, and reducing species are shown to diffuse on the order of hundreds of nanometers in solution. Copper nanoparticle growth was compared to Oswald ripening, and diffusion limited growth was observed at high electron dose rates. The diffusion limited growth was suppressed and led to a slower growth rate, with a calculated diffusion coefficient for Cu 2+ of 2 x 10--10 m2/s. Low electron dose rates corresponding to low magnifications in STEM yielded kinetic limited or mixed growth and yielded faceted nanoparticles. Atomic resolution was achieved in copper film deposited at low magnifications, and lattice fringes corresponding to the copper <111> were observed.

  20. Tumor endothelial marker 7 (TEM-7): a novel target for antiangiogenic therapy.

    PubMed

    Bagley, Rebecca G; Rouleau, Cecile; Weber, William; Mehraein, Khodadad; Smale, Robert; Curiel, Maritza; Callahan, Michelle; Roy, Andre; Boutin, Paula; St Martin, Thia; Nacht, Mariana; Teicher, Beverly A

    2011-11-01

    Antiangiogenesis has been validated as a therapeutic strategy to treat cancer, however, a need remains to identify new targets and therapies for specific diseases and to improve clinical benefit from antiangiogenic agents. Tumor endothelial marker 7 (TEM-7) was investigated as a possible target for therapeutic antiangiogenic intervention in cancer. TEM-7 expression was assessed by in situ hybridization or by immunohistochemistry (IHC) in 130 formalin-fixed paraffin-embedded (FFPE) and 410 frozen human clinical specimens of cancer plus 301 normal tissue samples. In vitro TEM-7 expression was evaluated in 4 human endothelial cell models and in 32 human cancer cell lines by RT-PCR and flow cytometry. An anti-TEM-7 antibody was tested in vitro on human SKOV3 ovarian and MDA-MB-231 breast carcinoma cells that expressed TEM-7 in antibody-dependent cellular cytotoxicity (ADCC) and phagocytosis assays. In frozen tumor tissues, TEM-7 mRNA and protein was detected in all but one of the cancer types tested and was infrequently expressed in normal frozen tissues. In FFPE tumor tissues, TEM-7 protein was detected by IHC in colon, breast, lung, bladder, ovarian and endometrial cancers and in sarcomas. TEM-7 protein was not detected in head and neck, prostate or liver cancers. TEM-7 expression was restricted to the vasculature and was absent from tumor cells. In vitro, TEM-7 was not detected in human microvascular endothelial cells (HMVEC) or human umbilical vein endothelial cells (HUVEC) but was induced in endothelial precursor/progenitor cells (EPC) in the presence of the mitogen phorbol ester PMA. An anti-TEM-7 antibody mediated ADCC and phagocytosis in SKOV3 and MDA-MB-231 cell lines infected with an adenovirus expressing TEM-7. These data demonstrate that TEM-7 is a vascular protein associated with angiogenic states. TEM-7 is a novel and attractive target for antiangiogenic therapy. Copyright © 2011 Elsevier Inc. All rights reserved.

  1. Gonococcal Antimicrobial Susceptibility and the Prevalence of blaTEM-1 and blaTEM-135 Genes in Neisseria gonorrhoeae Isolates from Thailand.

    PubMed

    Tribuddharat, Chanwit; Pongpech, Pintip; Charoenwatanachokchai, Angkana; Lokpichart, Somchai; Srifuengfung, Somporn; Sonprasert, Suthatta

    2017-03-24

    We studied the antimicrobial susceptibility and prevalence of the blaTEM-1 and blaTEM-135 genes in Neisseria gonorrhoeae isolates obtained in Thailand. The isolates were tested using the disk diffusion method, and 100% of 370 isolates were found susceptible to cefixime, ceftriaxone, cefotaxime, ceftazidime, cefepime, spectinomycin, and azithromycin. Some of the isolates were resistant to penicillin (85.7%), ciprofloxacin (88.0%), ofloxacin (97.4%), or tetracycline (89.1%). Penicillinase-producing N. gonorrhoeae accounted for 83.8% of isolates, with 70.0% of these further identified as penicillinase-producing plus tetracycline resistant N. gonorrhoeae. Penicillin, tetracycline, and ciprofloxacin are not recommended for treatment because of the high prevalence (89.7%) of multidrug resistant gonococci. A study of genes controlling enzyme of beta-lactamase production (blaTEM-1 and blaTEM-135) was performed using mismatch amplification mutation assay PCR method and DNA sequencing. Beta-lactamase positive N. gonorrhoeae carried blaTEM-1 (69.6%) and blaTEM-135 (30.4%), indicating that there is a significant increase and spread of blaTEM-135 among gonococci in Thailand.

  2. Evolution of the Mobile Information SysTem (MIST)

    NASA Technical Reports Server (NTRS)

    Litaker, Harry L., Jr.; Thompson, Shelby; Archer, Ronald D.

    2008-01-01

    The Mobile Information SysTem (MIST) had its origins in the need to determine whether commercial off the shelf (COTS) technologies could improve intervehicular activities (IVA) on International Space Station (ISS) crew maintenance productivity. It began with an exploration of head mounted displays (HMDs), but quickly evolved to include voice recognition, mobile personal computing, and data collection. The unique characteristic of the MIST lies within its mobility, in which a vest is worn that contains a mini-computer and supporting equipment, and a headband with attachments for a HMD, lipstick camera, and microphone. Data is then captured directly by the computer running Morae(TM) or similar software for analysis. To date, the MIST system has been tested in numerous environments such as two parabolic flights on NASA's C-9 microgravity aircraft and several mockup facilities ranging from ISS to the Altair Lunar Sortie Lander. Functional capabilities have included its lightweight and compact design, commonality across systems and environments, and usefulness in remote collaboration. Human Factors evaluations of the system have proven the MIST's ability to be worn for long durations of time (approximately four continuous hours) with no adverse physical deficits, moderate operator compensation, and low workload being reported as measured by Corlett Bishop Discomfort Scale, Cooper-Harper Ratings, and the NASA Total Workload Index (TLX), respectively. Additionally, through development of the system, it has spawned several new applications useful in research. For example, by only employing the lipstick camera, microphone, and a compact digital video recorder (DVR), we created a portable, lightweight data collection device. Video is recorded from the participants point of view (POV) through the use of the camera mounted on the side of the head. Both the video and audio is recorded directly into the DVR located on a belt around the waist. This data is then transferred to

  3. Carbonate Mineral Assemblages as Inclusions in Yakutian Diamonds: TEM Verifications

    NASA Astrophysics Data System (ADS)

    Logvinova, A. M.; Wirth, R.; Sobolev, N. V.; Taylor, L. A.

    2014-12-01

    Carbonate mineral inclusions are quite rare in diamonds from the upper mantle, but are evidence for a carbonate abundance in the mantle. It is believed that such carbonatitic inclusions originated from high-density fluids (HDFs) that were enclosed in diamond during its growth. Using TEM and EPMA, several kinds of carbonate inclusions have been identified in Yakutian diamonds : aragonite, dolomite, magnesite, Ba-, Sr-, and Fe-rich carbonates. Most of them are represented by multi-phase inclusions of various chemically distinct carbonates, rich in Ca, Mg, and K and associated with minor amounts of silicate, oxide, saline, and volatile phases. Volatiles, leaving some porosity, played a significant role in the diamond growth. A single crystal of aragonite (60μm) is herein reported for the first time. This inclusion is located in the center of a diamond from the Komsomolskaya pipe. Careful CL imaging reveals the total absence of cracks around the aragonite inclusion - i.e., closed system. This inclusion has been identified by X-ray diffraction and microprobe analysis. At temperatures above 1000 0C, aragonite is only stable at high pressures of 5-6 GPa. Inside this aragonite, we observed nanocrystalline inclusions of titanite, Ni-rich sulfide, magnetite, water-bearing Mg-silicate, and fluid bubbles. Dolomite is common in carbonate multi-phase inclusions in diamonds from the Internatsionalnaya, Yubileinaya, and Udachnaya kimberlite pipes. Alluvial diamonds of the northeastern Siberian Platform are divided into two groups based on the composition of HDFs: 1) Mg-rich multi-phase inclusions (60% magnesite + dolomite + Fe-spinel + Ti-silicate + fluid bubbles); and 2) Ca-rich multi-phase inclusions (Ca,Ba-, Ca,Sr-, Ca,Fe-carbonates + Ti-silicate + Ba-apatite + fluid bubbles). High-density fluids also contain K. Volatiles in the fluid bubbles are represented by water, Cl, F, S, CO2, CH4, and heavy hydrocarbons. Origin of the second group of HDFs may be related to the non

  4. Evolution of the Mobile Information SysTem (MIST)

    NASA Technical Reports Server (NTRS)

    Litaker, Harry L., Jr.; Thompson, Shelby; Archer, Ronald D.

    2008-01-01

    The Mobile Information SysTem (MIST) had its origins in the need to determine whether commercial off the shelf (COTS) technologies could improve intervehicular activities (IVA) on International Space Station (ISS) crew maintenance productivity. It began with an exploration of head mounted displays (HMDs), but quickly evolved to include voice recognition, mobile personal computing, and data collection. The unique characteristic of the MIST lies within its mobility, in which a vest is worn that contains a mini-computer and supporting equipment, and a headband with attachments for a HMD, lipstick camera, and microphone. Data is then captured directly by the computer running Morae(TM) or similar software for analysis. To date, the MIST system has been tested in numerous environments such as two parabolic flights on NASA's C-9 microgravity aircraft and several mockup facilities ranging from ISS to the Altair Lunar Sortie Lander. Functional capabilities have included its lightweight and compact design, commonality across systems and environments, and usefulness in remote collaboration. Human Factors evaluations of the system have proven the MIST's ability to be worn for long durations of time (approximately four continuous hours) with no adverse physical deficits, moderate operator compensation, and low workload being reported as measured by Corlett Bishop Discomfort Scale, Cooper-Harper Ratings, and the NASA Total Workload Index (TLX), respectively. Additionally, through development of the system, it has spawned several new applications useful in research. For example, by only employing the lipstick camera, microphone, and a compact digital video recorder (DVR), we created a portable, lightweight data collection device. Video is recorded from the participants point of view (POV) through the use of the camera mounted on the side of the head. Both the video and audio is recorded directly into the DVR located on a belt around the waist. This data is then transferred to

  5. Multimedia Analysis plus Visual Analytics = Multimedia Analytics

    SciTech Connect

    Chinchor, Nancy; Thomas, James J.; Wong, Pak C.; Christel, Michael; Ribarsky, Martin W.

    2010-10-01

    Multimedia analysis has focused on images, video, and to some extent audio and has made progress in single channels excluding text. Visual analytics has focused on the user interaction with data during the analytic process plus the fundamental mathematics and has continued to treat text as did its precursor, information visualization. The general problem we address in this tutorial is the combining of multimedia analysis and visual analytics to deal with multimedia information gathered from different sources, with different goals or objectives, and containing all media types and combinations in common usage.

  6. Development of 89Zr-Ontuxizumab for in vivo TEM-1/endosialin PET applications.

    PubMed

    Lange, Sara E S; Zheleznyak, Alex; Studer, Matthew; O'Shannessy, Daniel J; Lapi, Suzanne E; Van Tine, Brian A

    2016-03-15

    The complexity of sarcoma has led to the need for patient selection via in vivo biomarkers. Tumor endothelial marker-1 (TEM-1) is a cell surface marker expressed by the tumor microenvironment. Currently MORAb-004 (Ontuxizumab), an anti-TEM-1 humanized monoclonal antibody, is in sarcoma clinical trials. Development of positron emission tomography (PET) for in vivo TEM-1 expression may allow for stratification of patients, potentially enhancing clinical outcomes seen with Ontuxizumab. Characterization of cell lines revealed clear differences in TEM-1 expression. One high expressing (RD-ES) and one low expressing (LUPI) cell line were xenografted, and mice were injected with 89Zr-Ontuxizumab. PET imaging post-injection revealed that TEM-1 was highly expressed and readily detectable in vivo only in RD-ES. In vivo biodistribution studies confirmed high radiopharmaceutical uptake in tumor relative to normal organs. Sarcoma cell lines were characterized for TEM-1 expression. Ontuxizumab was labeled with 89Zr and evaluated for immunoreactivity preservation. 89Zr-Ontuxizumab was injected into mice with high or null expressing TEM-1 xenografts. In vivo PET imaging experiments were performed. 89Zr-Ontuxizumab can be used in vivo to determine high versus low TEM-1 expression. Reliable PET imaging of TEM-1 in sarcoma patients may allow for identification of patients that will attain the greatest benefit from anti-TEM-1 therapy.

  7. Direct observation of liquid crystals using cryo-TEM: specimen preparation and low-dose imaging.

    PubMed

    Gao, Min; Kim, Young-Ki; Zhang, Cuiyu; Borshch, Volodymyr; Zhou, Shuang; Park, Heung-Shik; Jákli, Antal; Lavrentovich, Oleg D; Tamba, Maria-Gabriela; Kohlmeier, Alexandra; Mehl, Georg H; Weissflog, Wolfgang; Studer, Daniel; Zuber, Benoît; Gnägi, Helmut; Lin, Fang

    2014-10-01

    Liquid crystals (LCs) represent a challenging group of materials for direct transmission electron microscopy (TEM) studies due to the complications in specimen preparation and the severe radiation damage. In this paper, we summarize a series of specimen preparation methods, including thin film and cryo-sectioning approaches, as a comprehensive toolset enabling high-resolution direct cryo-TEM observation of a broad range of LCs. We also present comparative analysis using cryo-TEM and replica freeze-fracture TEM on both thermotropic and lyotropic LCs. In addition to the revisits of previous practices, some new concepts are introduced, e.g., suspended thermotropic LC thin films, combined high-pressure freezing and cryo-sectioning of lyotropic LCs, and the complementary applications of direct TEM and indirect replica TEM techniques. The significance of subnanometer resolution cryo-TEM observation is demonstrated in a few important issues in LC studies, including providing direct evidences for the existence of nanoscale smectic domains in nematic bent-core thermotropic LCs, comprehensive understanding of the twist-bend nematic phase, and probing the packing of columnar aggregates in lyotropic chromonic LCs. Direct TEM observation opens ways to a variety of TEM techniques, suggesting that TEM (replica, cryo, and in situ techniques), in general, may be a promising part of the solution to the lack of effective structural probe at the molecular scale in LC studies. © 2014 Wiley Periodicals, Inc.

  8. Using ground-based geophysics to constrain the interpretation of airborne TEM data recorded across the Okavango Delta, Botswana

    NASA Astrophysics Data System (ADS)

    Podgorski, J. E.; Kalscheuer, T.; Doetsch, J.; Rabenstein, L.; Tshoso, G.; Meier, P.; Horstmeyer, H.; Kgotlhang, L.; Ploug, C.; Auken, E.; Kinzelbach, W. K.; Green, A. G.

    2011-12-01

    The Okavango Delta in northern Botswana is a near endorheic inland delta that has developed over the past ~2 MA in an active graben at the southwestern end of the East Africa Rift System. An annual flood from the north causes a slowly flowing surface water regime in the delta, but previous wetter climatic periods were responsible for intermittent lacustrine environments. The Okavango Delta is the largest permanent water body in the Kalahari Desert and, as such, represents an important resource for wildlife and humans alike. An airborne time-domain electromagnetic (TEM) survey, commissioned by the Botswana government, was undertaken in 2007 for the purpose of better understanding the hydrogeology of the delta. Initial processing and inversion of these data show within the main fan of the delta a resistive 20-50 m thick surface layer underlain by a 30-200 m thick conductive layer. In the upper fan, the conductive layer is underlain by a resistive unit beginning at about 150 m depth. This unit exhibits a dendritic pattern implying a fluvial origin. To help interpret this and other structures, geophysical field work was initiated in early 2011 at various locations in the delta. Seismic reflection and refraction, electrical resistive tomography (ERT), and ground TEM methods were employed. The seismic methods are useful for delineating the boundaries of the weathering and basement layers, whereas ERT provides an independent estimate of the resistivity structure, particularly at shallow depths. Ground TEM allows for a direct comparison with the airborne TEM soundings, helping to estimate the accuracy of the latter. Though still evolving, the current large-scale hydrogeological interpretation of the airborne data set includes a fresh water-saturated surface layer underlain by a saline aquifer and clay aquitard. In the upper fan of the delta, a fresh water aquifer appears to lie between the aquitard and the basement rock.

  9. EBSD and TEM investigation of the hot deformation substructure characteristics of a type 316L austenitic stainless steel.

    PubMed

    Cizek, P; Whiteman, J A; Rainforth, W M; Beynon, J H

    2004-03-01

    The evolution of crystallographic texture and deformation substructure was studied in a type 316L austenitic stainless steel, deformed in rolling at 900 degrees C to true strain levels of about 0.3 and 0.7. Electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) were used in the investigation and a comparison of the substructural characteristics obtained by these techniques was made. At the lower strain level, the deformation substructure observed by EBSD appeared to be rather poorly developed. There was considerable evidence of a rotation of the pre-existing twin boundaries from their original orientation relationship, as well as the formation of highly distorted grain boundary regions. In TEM, at this strain level, the substructure was more clearly revealed, although it appeared rather inhomogeneously developed from grain to grain. The subgrains were frequently elongated and their boundaries often approximated to traces of [111] slip planes. The corresponding misorientations were small and largely displayed a non-cumulative character. At the larger strain, the substructure within most grains became well developed and the corresponding misorientations increased. This resulted in better detection of sub-boundaries by EBSD, although the percentage of indexing slightly decreased. TEM revealed splitting of some sub-boundaries to form fine microbands, as well as the localized formation of microshear bands. The substructural characteristics observed by EBSD, in particular at the larger strain, generally appeared to compare well with those obtained using TEM. With increased strain level, the mean subgrain size became finer, the corresponding mean misorientation angle increased and both these characteristics became less dependent on a particular grain orientation. The statistically representative data obtained will assist in the development of physically based models of microstructural evolution during thermomechanical processing of austenitic

  10. Analytical Challenges in Biotechnology.

    ERIC Educational Resources Information Center

    Glajch, Joseph L.

    1986-01-01

    Highlights five major analytical areas (electrophoresis, immunoassay, chromatographic separations, protein and DNA sequencing, and molecular structures determination) and discusses how analytical chemistry could further improve these techniques and thereby have a major impact on biotechnology. (JN)

  11. Analytical Challenges in Biotechnology.

    ERIC Educational Resources Information Center

    Glajch, Joseph L.

    1986-01-01

    Highlights five major analytical areas (electrophoresis, immunoassay, chromatographic separations, protein and DNA sequencing, and molecular structures determination) and discusses how analytical chemistry could further improve these techniques and thereby have a major impact on biotechnology. (JN)

  12. Analyticity without Differentiability

    ERIC Educational Resources Information Center

    Kirillova, Evgenia; Spindler, Karlheinz

    2008-01-01

    In this article we derive all salient properties of analytic functions, including the analytic version of the inverse function theorem, using only the most elementary convergence properties of series. Not even the notion of differentiability is required to do so. Instead, analytical arguments are replaced by combinatorial arguments exhibiting…

  13. Quench in superconducting magnets. 2: Analytic solution

    NASA Astrophysics Data System (ADS)

    Shajii, A.; Freidberg, J. P.

    1994-09-01

    A set of analytic solutions fo