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Sample records for sampling small solution

  1. Maybe Small Is Too Small a Term: Introduction to Advancing Small Sample Prevention Science.

    Science.gov (United States)

    Fok, Carlotta Ching Ting; Henry, David; Allen, James

    2015-10-01

    Prevention research addressing health disparities often involves work with small population groups experiencing such disparities. The goals of this special section are to (1) address the question of what constitutes a small sample; (2) identify some of the key research design and analytic issues that arise in prevention research with small samples; (3) develop applied, problem-oriented, and methodologically innovative solutions to these design and analytic issues; and (4) evaluate the potential role of these innovative solutions in describing phenomena, testing theory, and evaluating interventions in prevention research. Through these efforts, we hope to promote broader application of these methodological innovations. We also seek whenever possible, to explore their implications in more general problems that appear in research with small samples but concern all areas of prevention research. This special section includes two sections. The first section aims to provide input for researchers at the design phase, while the second focuses on analysis. Each article describes an innovative solution to one or more challenges posed by the analysis of small samples, with special emphasis on testing for intervention effects in prevention research. A concluding article summarizes some of their broader implications, along with conclusions regarding future directions in research with small samples in prevention science. Finally, a commentary provides the perspective of the federal agencies that sponsored the conference that gave rise to this special section.

  2. Test of a sample container for shipment of small size plutonium samples with PAT-2

    International Nuclear Information System (INIS)

    Kuhn, E.; Aigner, H.; Deron, S.

    1981-11-01

    A light-weight container for the air transport of plutonium, to be designated PAT-2, has been developed in the USA and is presently undergoing licensing. The very limited effective space for bearing plutonium required the design of small size sample canisters to meet the needs of international safeguards for the shipment of plutonium samples. The applicability of a small canister for the sampling of small size powder and solution samples has been tested in an intralaboratory experiment. The results of the experiment, based on the concept of pre-weighed samples, show that the tested canister can successfully be used for the sampling of small size PuO 2 -powder samples of homogeneous source material, as well as for dried aliquands of plutonium nitrate solutions. (author)

  3. Measurements of accurate x-ray scattering data of protein solutions using small stationary sample cells

    Science.gov (United States)

    Hong, Xinguo; Hao, Quan

    2009-01-01

    In this paper, we report a method of precise in situ x-ray scattering measurements on protein solutions using small stationary sample cells. Although reduction in the radiation damage induced by intense synchrotron radiation sources is indispensable for the correct interpretation of scattering data, there is still a lack of effective methods to overcome radiation-induced aggregation and extract scattering profiles free from chemical or structural damage. It is found that radiation-induced aggregation mainly begins on the surface of the sample cell and grows along the beam path; the diameter of the damaged region is comparable to the x-ray beam size. Radiation-induced aggregation can be effectively avoided by using a two-dimensional scan (2D mode), with an interval as small as 1.5 times the beam size, at low temperature (e.g., 4 °C). A radiation sensitive protein, bovine hemoglobin, was used to test the method. A standard deviation of less than 5% in the small angle region was observed from a series of nine spectra recorded in 2D mode, in contrast to the intensity variation seen using the conventional stationary technique, which can exceed 100%. Wide-angle x-ray scattering data were collected at a standard macromolecular diffraction station using the same data collection protocol and showed a good signal/noise ratio (better than the reported data on the same protein using a flow cell). The results indicate that this method is an effective approach for obtaining precise measurements of protein solution scattering.

  4. Measurements of accurate x-ray scattering data of protein solutions using small stationary sample cells

    International Nuclear Information System (INIS)

    Hong Xinguo; Hao Quan

    2009-01-01

    In this paper, we report a method of precise in situ x-ray scattering measurements on protein solutions using small stationary sample cells. Although reduction in the radiation damage induced by intense synchrotron radiation sources is indispensable for the correct interpretation of scattering data, there is still a lack of effective methods to overcome radiation-induced aggregation and extract scattering profiles free from chemical or structural damage. It is found that radiation-induced aggregation mainly begins on the surface of the sample cell and grows along the beam path; the diameter of the damaged region is comparable to the x-ray beam size. Radiation-induced aggregation can be effectively avoided by using a two-dimensional scan (2D mode), with an interval as small as 1.5 times the beam size, at low temperature (e.g., 4 deg. C). A radiation sensitive protein, bovine hemoglobin, was used to test the method. A standard deviation of less than 5% in the small angle region was observed from a series of nine spectra recorded in 2D mode, in contrast to the intensity variation seen using the conventional stationary technique, which can exceed 100%. Wide-angle x-ray scattering data were collected at a standard macromolecular diffraction station using the same data collection protocol and showed a good signal/noise ratio (better than the reported data on the same protein using a flow cell). The results indicate that this method is an effective approach for obtaining precise measurements of protein solution scattering.

  5. Gaseous radiocarbon measurements of small samples

    International Nuclear Information System (INIS)

    Ruff, M.; Szidat, S.; Gaeggeler, H.W.; Suter, M.; Synal, H.-A.; Wacker, L.

    2010-01-01

    Radiocarbon dating by means of accelerator mass spectrometry (AMS) is a well-established method for samples containing carbon in the milligram range. However, the measurement of small samples containing less than 50 μg carbon often fails. It is difficult to graphitise these samples and the preparation is prone to contamination. To avoid graphitisation, a solution can be the direct measurement of carbon dioxide. The MICADAS, the smallest accelerator for radiocarbon dating in Zurich, is equipped with a hybrid Cs sputter ion source. It allows the measurement of both, graphite targets and gaseous CO 2 samples, without any rebuilding. This work presents experiences dealing with small samples containing 1-40 μg carbon. 500 unknown samples of different environmental research fields have been measured yet. Most of the samples were measured with the gas ion source. These data are compared with earlier measurements of small graphite samples. The performance of the two different techniques is discussed and main contributions to the blank determined. An analysis of blank and standard data measured within years allowed a quantification of the contamination, which was found to be of the order of 55 ng and 750 ng carbon (50 pMC) for the gaseous and the graphite samples, respectively. For quality control, a number of certified standards were measured using the gas ion source to demonstrate reliability of the data.

  6. Pitfall in quantum mechanical/molecular mechanical molecular dynamics simulation of small solutes in solution.

    Science.gov (United States)

    Hu, Hao; Liu, Haiyan

    2013-05-30

    Developments in computing hardware and algorithms have made direct molecular dynamics simulation with the combined quantum mechanical/molecular mechanical methods affordable for small solute molecules in solution, in which much improved accuracy can be obtained via the quantum mechanical treatment of the solute molecule and even sometimes water molecules in the first solvation shell. However, unlike the conventional molecular mechanical simulations of large molecules, e.g., proteins, in solutions, special care must be taken in the technical details of the simulation, including the thermostat of the solute/solvent system, so that the conformational space of the solute molecules can be properly sampled. We show here that the common setup for classical molecular mechanical molecular dynamics simulations, such as the Berendsen or single Nose-Hoover thermostat, and/or rigid water models could lead to pathological sampling of the solutes' conformation. In the extreme example of a methanol molecule in aqueous solution, improper and sluggish setups could generate two peaks in the distribution of the O-H bond length. We discuss the factors responsible for this somewhat unexpected result and evoke a simple and ancient technical fix-up to resolve this problem.

  7. A Geology Sampling System for Small Bodies

    Science.gov (United States)

    Naids, Adam J.; Hood, Anthony D.; Abell, Paul; Graff, Trevor; Buffington, Jesse

    2016-01-01

    Human exploration of microgravity bodies is being investigated as a precursor to a Mars surface mission. Asteroids, comets, dwarf planets, and the moons of Mars all fall into this microgravity category and some are being discussed as potential mission targets. Obtaining geological samples for return to Earth will be a major objective for any mission to a small body. Currently, the knowledge base for geology sampling in microgravity is in its infancy. Humans interacting with non-engineered surfaces in microgravity environment pose unique challenges. In preparation for such missions a team at the NASA Johnson Space Center has been working to gain experience on how to safely obtain numerous sample types in such an environment. This paper describes the type of samples the science community is interested in, highlights notable prototype work, and discusses an integrated geology sampling solution.

  8. In situ sampling of small volumes of soil solution using modified micro-suction cups

    NARCIS (Netherlands)

    Shen, Jianbo; Hoffland, E.

    2007-01-01

    Two modified designs of micro-pore-water samplers were tested for their capacity to collect unbiased soil solution samples containing zinc and citrate. The samplers had either ceramic or polyethersulfone (PES) suction cups. Laboratory tests of the micro-samplers were conducted using (a) standard

  9. Data Analysis Of Small Angle X-Ray Solution Scattering And Its ...

    African Journals Online (AJOL)

    Small Angle X-ray Scattering analysis was used for the study of the protein, Human Tumour Necrosis Factor (TNF) homogeneously dispersed in solution. The experiment consisted in sending a well collimated beam of synchrotron radiation of wavelength, λ through the sample and measuring the variation of the intensity as a ...

  10. Big Data, Small Sample.

    Science.gov (United States)

    Gerlovina, Inna; van der Laan, Mark J; Hubbard, Alan

    2017-05-20

    Multiple comparisons and small sample size, common characteristics of many types of "Big Data" including those that are produced by genomic studies, present specific challenges that affect reliability of inference. Use of multiple testing procedures necessitates calculation of very small tail probabilities of a test statistic distribution. Results based on large deviation theory provide a formal condition that is necessary to guarantee error rate control given practical sample sizes, linking the number of tests and the sample size; this condition, however, is rarely satisfied. Using methods that are based on Edgeworth expansions (relying especially on the work of Peter Hall), we explore the impact of departures of sampling distributions from typical assumptions on actual error rates. Our investigation illustrates how far the actual error rates can be from the declared nominal levels, suggesting potentially wide-spread problems with error rate control, specifically excessive false positives. This is an important factor that contributes to "reproducibility crisis". We also review some other commonly used methods (such as permutation and methods based on finite sampling inequalities) in their application to multiple testing/small sample data. We point out that Edgeworth expansions, providing higher order approximations to the sampling distribution, offer a promising direction for data analysis that could improve reliability of studies relying on large numbers of comparisons with modest sample sizes.

  11. Small-sample-worth perturbation methods

    International Nuclear Information System (INIS)

    1985-01-01

    It has been assumed that the perturbed region, R/sub p/, is large enough so that: (1) even without a great deal of biasing there is a substantial probability that an average source-neutron will enter it; and (2) once having entered, the neutron is likely to make several collisions in R/sub p/ during its lifetime. Unfortunately neither assumption is valid for the typical configurations one encounters in small-sample-worth experiments. In such experiments one measures the reactivity change which is induced when a very small void in a critical assembly is filled with a sample of some test-material. Only a minute fraction of the fission-source neutrons ever gets into the sample and, of those neutrons that do, most emerge uncollided. Monte Carlo small-sample perturbations computations are described

  12. Standard Deviation for Small Samples

    Science.gov (United States)

    Joarder, Anwar H.; Latif, Raja M.

    2006-01-01

    Neater representations for variance are given for small sample sizes, especially for 3 and 4. With these representations, variance can be calculated without a calculator if sample sizes are small and observations are integers, and an upper bound for the standard deviation is immediate. Accessible proofs of lower and upper bounds are presented for…

  13. SAMPL5: 3D-RISM partition coefficient calculations with partial molar volume corrections and solute conformational sampling

    Science.gov (United States)

    Luchko, Tyler; Blinov, Nikolay; Limon, Garrett C.; Joyce, Kevin P.; Kovalenko, Andriy

    2016-11-01

    Implicit solvent methods for classical molecular modeling are frequently used to provide fast, physics-based hydration free energies of macromolecules. Less commonly considered is the transferability of these methods to other solvents. The Statistical Assessment of Modeling of Proteins and Ligands 5 (SAMPL5) distribution coefficient dataset and the accompanying explicit solvent partition coefficient reference calculations provide a direct test of solvent model transferability. Here we use the 3D reference interaction site model (3D-RISM) statistical-mechanical solvation theory, with a well tested water model and a new united atom cyclohexane model, to calculate partition coefficients for the SAMPL5 dataset. The cyclohexane model performed well in training and testing (R=0.98 for amino acid neutral side chain analogues) but only if a parameterized solvation free energy correction was used. In contrast, the same protocol, using single solute conformations, performed poorly on the SAMPL5 dataset, obtaining R=0.73 compared to the reference partition coefficients, likely due to the much larger solute sizes. Including solute conformational sampling through molecular dynamics coupled with 3D-RISM (MD/3D-RISM) improved agreement with the reference calculation to R=0.93. Since our initial calculations only considered partition coefficients and not distribution coefficients, solute sampling provided little benefit comparing against experiment, where ionized and tautomer states are more important. Applying a simple pK_{ {a}} correction improved agreement with experiment from R=0.54 to R=0.66, despite a small number of outliers. Better agreement is possible by accounting for tautomers and improving the ionization correction.

  14. SAMPL5: 3D-RISM partition coefficient calculations with partial molar volume corrections and solute conformational sampling.

    Science.gov (United States)

    Luchko, Tyler; Blinov, Nikolay; Limon, Garrett C; Joyce, Kevin P; Kovalenko, Andriy

    2016-11-01

    Implicit solvent methods for classical molecular modeling are frequently used to provide fast, physics-based hydration free energies of macromolecules. Less commonly considered is the transferability of these methods to other solvents. The Statistical Assessment of Modeling of Proteins and Ligands 5 (SAMPL5) distribution coefficient dataset and the accompanying explicit solvent partition coefficient reference calculations provide a direct test of solvent model transferability. Here we use the 3D reference interaction site model (3D-RISM) statistical-mechanical solvation theory, with a well tested water model and a new united atom cyclohexane model, to calculate partition coefficients for the SAMPL5 dataset. The cyclohexane model performed well in training and testing ([Formula: see text] for amino acid neutral side chain analogues) but only if a parameterized solvation free energy correction was used. In contrast, the same protocol, using single solute conformations, performed poorly on the SAMPL5 dataset, obtaining [Formula: see text] compared to the reference partition coefficients, likely due to the much larger solute sizes. Including solute conformational sampling through molecular dynamics coupled with 3D-RISM (MD/3D-RISM) improved agreement with the reference calculation to [Formula: see text]. Since our initial calculations only considered partition coefficients and not distribution coefficients, solute sampling provided little benefit comparing against experiment, where ionized and tautomer states are more important. Applying a simple [Formula: see text] correction improved agreement with experiment from [Formula: see text] to [Formula: see text], despite a small number of outliers. Better agreement is possible by accounting for tautomers and improving the ionization correction.

  15. Determination of phosphorus in small amounts of protein samples by ICP-MS.

    Science.gov (United States)

    Becker, J Sabine; Boulyga, Sergei F; Pickhardt, Carola; Becker, J; Buddrus, Stefan; Przybylski, Michael

    2003-02-01

    Inductively coupled plasma mass spectrometry (ICP-MS) is used for phosphorus determination in protein samples. A small amount of solid protein sample (down to 1 micro g) or digest (1-10 micro L) protein solution was denatured in nitric acid and hydrogen peroxide by closed-microvessel microwave digestion. Phosphorus determination was performed with an optimized analytical method using a double-focusing sector field inductively coupled plasma mass spectrometer (ICP-SFMS) and quadrupole-based ICP-MS (ICP-QMS). For quality control of phosphorus determination a certified reference material (CRM), single cell proteins (BCR 273) with a high phosphorus content of 26.8+/-0.4 mg g(-1), was analyzed. For studies on phosphorus determination in proteins while reducing the sample amount as low as possible the homogeneity of CRM BCR 273 was investigated. Relative standard deviation and measurement accuracy in ICP-QMS was within 2%, 3.5%, 11% and 12% when using CRM BCR 273 sample weights of 40 mg, 5 mg, 1 mg and 0.3 mg, respectively. The lowest possible sample weight for an accurate phosphorus analysis in protein samples by ICP-MS is discussed. The analytical method developed was applied for the analysis of homogeneous protein samples in very low amounts [1-100 micro g of solid protein sample, e.g. beta-casein or down to 1 micro L of protein or digest in solution (e.g., tau protein)]. A further reduction of the diluted protein solution volume was achieved by the application of flow injection in ICP-SFMS, which is discussed with reference to real protein digests after protein separation using 2D gel electrophoresis.The detection limits for phosphorus in biological samples were determined by ICP-SFMS down to the ng g(-1) level. The present work discusses the figure of merit for the determination of phosphorus in a small amount of protein sample with ICP-SFMS in comparison to ICP-QMS.

  16. Solution-based targeted genomic enrichment for precious DNA samples

    Directory of Open Access Journals (Sweden)

    Shearer Aiden

    2012-05-01

    Full Text Available Abstract Background Solution-based targeted genomic enrichment (TGE protocols permit selective sequencing of genomic regions of interest on a massively parallel scale. These protocols could be improved by: 1 modifying or eliminating time consuming steps; 2 increasing yield to reduce input DNA and excessive PCR cycling; and 3 enhancing reproducible. Results We developed a solution-based TGE method for downstream Illumina sequencing in a non-automated workflow, adding standard Illumina barcode indexes during the post-hybridization amplification to allow for sample pooling prior to sequencing. The method utilizes Agilent SureSelect baits, primers and hybridization reagents for the capture, off-the-shelf reagents for the library preparation steps, and adaptor oligonucleotides for Illumina paired-end sequencing purchased directly from an oligonucleotide manufacturing company. Conclusions This solution-based TGE method for Illumina sequencing is optimized for small- or medium-sized laboratories and addresses the weaknesses of standard protocols by reducing the amount of input DNA required, increasing capture yield, optimizing efficiency, and improving reproducibility.

  17. Direct visualization of solute locations in laboratory ice samples

    Directory of Open Access Journals (Sweden)

    T. Hullar

    2016-09-01

    Full Text Available Many important chemical reactions occur in polar snow, where solutes may be present in several reservoirs, including at the air–ice interface and in liquid-like regions within the ice matrix. Some recent laboratory studies suggest chemical reaction rates may differ in these two reservoirs. While investigations have examined where solutes are found in natural snow and ice, few studies have examined either solute locations in laboratory samples or the possible factors controlling solute segregation. To address this, we used micro-computed tomography (microCT to examine solute locations in ice samples prepared from either aqueous cesium chloride (CsCl or rose bengal solutions that were frozen using several different methods. Samples frozen in a laboratory freezer had the largest liquid-like inclusions and air bubbles, while samples frozen in a custom freeze chamber had somewhat smaller air bubbles and inclusions; in contrast, samples frozen in liquid nitrogen showed much smaller concentrated inclusions and air bubbles, only slightly larger than the resolution limit of our images (∼ 2 µm. Freezing solutions in plastic vs. glass vials had significant impacts on the sample structure, perhaps because the poor heat conductivity of plastic vials changes how heat is removed from the sample as it cools. Similarly, the choice of solute had a significant impact on sample structure, with rose bengal solutions yielding smaller inclusions and air bubbles compared to CsCl solutions frozen using the same method. Additional experiments using higher-resolution imaging of an ice sample show that CsCl moves in a thermal gradient, supporting the idea that the solutes in ice are present in mobile liquid-like regions. Our work shows that the structure of laboratory ice samples, including the location of solutes, is sensitive to the freezing method, sample container, and solute characteristics, requiring careful experimental design and interpretation of results.

  18. Searching for the Optimal Sampling Solution: Variation in Invertebrate Communities, Sample Condition and DNA Quality.

    Directory of Open Access Journals (Sweden)

    Martin M Gossner

    Full Text Available There is a great demand for standardising biodiversity assessments in order to allow optimal comparison across research groups. For invertebrates, pitfall or flight-interception traps are commonly used, but sampling solution differs widely between studies, which could influence the communities collected and affect sample processing (morphological or genetic. We assessed arthropod communities with flight-interception traps using three commonly used sampling solutions across two forest types and two vertical strata. We first considered the effect of sampling solution and its interaction with forest type, vertical stratum, and position of sampling jar at the trap on sample condition and community composition. We found that samples collected in copper sulphate were more mouldy and fragmented relative to other solutions which might impair morphological identification, but condition depended on forest type, trap type and the position of the jar. Community composition, based on order-level identification, did not differ across sampling solutions and only varied with forest type and vertical stratum. Species richness and species-level community composition, however, differed greatly among sampling solutions. Renner solution was highly attractant for beetles and repellent for true bugs. Secondly, we tested whether sampling solution affects subsequent molecular analyses and found that DNA barcoding success was species-specific. Samples from copper sulphate produced the fewest successful DNA sequences for genetic identification, and since DNA yield or quality was not particularly reduced in these samples additional interactions between the solution and DNA must also be occurring. Our results show that the choice of sampling solution should be an important consideration in biodiversity studies. Due to the potential bias towards or against certain species by Ethanol-containing sampling solution we suggest ethylene glycol as a suitable sampling solution when

  19. BioSAXS Sample Changer: a robotic sample changer for rapid and reliable high-throughput X-ray solution scattering experiments

    Energy Technology Data Exchange (ETDEWEB)

    Round, Adam, E-mail: around@embl.fr; Felisaz, Franck [European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble (France); Université Grenoble Alpes–EMBL–CNRS, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble (France); Fodinger, Lukas; Gobbo, Alexandre [European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble (France); Huet, Julien [European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble (France); Université Grenoble Alpes–EMBL–CNRS, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble (France); Villard, Cyril [European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble (France); Blanchet, Clement E., E-mail: around@embl.fr [EMBL c/o DESY, Notkestrasse 85, 22603 Hamburg (Germany); Pernot, Petra; McSweeney, Sean [ESRF, 6 Rue Jules Horowitz, 38000 Grenoble (France); Roessle, Manfred; Svergun, Dmitri I. [EMBL c/o DESY, Notkestrasse 85, 22603 Hamburg (Germany); Cipriani, Florent, E-mail: around@embl.fr [European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble (France); Université Grenoble Alpes–EMBL–CNRS, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble (France)

    2015-01-01

    A robotic sample changer for solution X-ray scattering experiments optimized for speed and to use the minimum amount of material has been developed. This system is now in routine use at three high-brilliance European synchrotron sites, each capable of several hundred measurements per day. Small-angle X-ray scattering (SAXS) of macromolecules in solution is in increasing demand by an ever more diverse research community, both academic and industrial. To better serve user needs, and to allow automated and high-throughput operation, a sample changer (BioSAXS Sample Changer) that is able to perform unattended measurements of up to several hundred samples per day has been developed. The Sample Changer is able to handle and expose sample volumes of down to 5 µl with a measurement/cleaning cycle of under 1 min. The samples are stored in standard 96-well plates and the data are collected in a vacuum-mounted capillary with automated positioning of the solution in the X-ray beam. Fast and efficient capillary cleaning avoids cross-contamination and ensures reproducibility of the measurements. Independent temperature control for the well storage and for the measurement capillary allows the samples to be kept cool while still collecting data at physiological temperatures. The Sample Changer has been installed at three major third-generation synchrotrons: on the BM29 beamline at the European Synchrotron Radiation Facility (ESRF), the P12 beamline at the PETRA-III synchrotron (EMBL@PETRA-III) and the I22/B21 beamlines at Diamond Light Source, with the latter being the first commercial unit supplied by Bruker ASC.

  20. Robust, high-throughput solution structural analyses by small angle X-ray scattering (SAXS)

    Energy Technology Data Exchange (ETDEWEB)

    Hura, Greg L.; Menon, Angeli L.; Hammel, Michal; Rambo, Robert P.; Poole II, Farris L.; Tsutakawa, Susan E.; Jenney Jr, Francis E.; Classen, Scott; Frankel, Kenneth A.; Hopkins, Robert C.; Yang, Sungjae; Scott, Joseph W.; Dillard, Bret D.; Adams, Michael W. W.; Tainer, John A.

    2009-07-20

    We present an efficient pipeline enabling high-throughput analysis of protein structure in solution with small angle X-ray scattering (SAXS). Our SAXS pipeline combines automated sample handling of microliter volumes, temperature and anaerobic control, rapid data collection and data analysis, and couples structural analysis with automated archiving. We subjected 50 representative proteins, mostly from Pyrococcus furiosus, to this pipeline and found that 30 were multimeric structures in solution. SAXS analysis allowed us to distinguish aggregated and unfolded proteins, define global structural parameters and oligomeric states for most samples, identify shapes and similar structures for 25 unknown structures, and determine envelopes for 41 proteins. We believe that high-throughput SAXS is an enabling technology that may change the way that structural genomics research is done.

  1. Small deformations of the Prasad-Sommerfield solution

    International Nuclear Information System (INIS)

    Adler, S.L.

    1979-01-01

    I study solutions of the static Euclidean anti-self-dual SU(2) Yang-Mills equations which differ by a small perturbation from the Prasad-Sommerfield solution. I find explicit expressions for two series of perturbation mode functions of angular momentum l and even and odd parity, and classify the modes according to several criteria. There are seven nondilatational modes which have singularities removable by gauge transformation: 3 translations (l = 1), 1 gauge mode (l = 0), and a family of 3 odd-parity gauge modes (l = 1). The translations and l = 0 gauge modes have nonvanishing, and normalizable, projections into the background gauge, while the odd-parity l = 1 modes have vanishing projection into the background gauge. Among the singular modes, there are an infinite number of modes, irregular at r = 0, which nonetheless satisfy the boundary conditions for finite-energy solutions on the sphere at infinity. I show, by discussing the analogous problem of the axially symmetric solutions of the stationary Einstein equations, that non-normalizable modes are relevant in determining whether a spherically symmetric solution of a nonlinear system has axially symmetric extensions. The analysis of perturbations around the Prasad-Sommerfield solution implies that if an axially symmetric extension exists, it cannot be reached by integration out along a tangent vector defined by a nonvanishing, nonsingular small-perturbation mode of the class explicitly constructed

  2. An Improvement to Interval Estimation for Small Samples

    Directory of Open Access Journals (Sweden)

    SUN Hui-Ling

    2017-02-01

    Full Text Available Because it is difficult and complex to determine the probability distribution of small samples,it is improper to use traditional probability theory to process parameter estimation for small samples. Bayes Bootstrap method is always used in the project. Although,the Bayes Bootstrap method has its own limitation,In this article an improvement is given to the Bayes Bootstrap method,This method extended the amount of samples by numerical simulation without changing the circumstances in a small sample of the original sample. And the new method can give the accurate interval estimation for the small samples. Finally,by using the Monte Carlo simulation to model simulation to the specific small sample problems. The effectiveness and practicability of the Improved-Bootstrap method was proved.

  3. Comparing interval estimates for small sample ordinal CFA models.

    Science.gov (United States)

    Natesan, Prathiba

    2015-01-01

    Robust maximum likelihood (RML) and asymptotically generalized least squares (AGLS) methods have been recommended for fitting ordinal structural equation models. Studies show that some of these methods underestimate standard errors. However, these studies have not investigated the coverage and bias of interval estimates. An estimate with a reasonable standard error could still be severely biased. This can only be known by systematically investigating the interval estimates. The present study compares Bayesian, RML, and AGLS interval estimates of factor correlations in ordinal confirmatory factor analysis models (CFA) for small sample data. Six sample sizes, 3 factor correlations, and 2 factor score distributions (multivariate normal and multivariate mildly skewed) were studied. Two Bayesian prior specifications, informative and relatively less informative were studied. Undercoverage of confidence intervals and underestimation of standard errors was common in non-Bayesian methods. Underestimated standard errors may lead to inflated Type-I error rates. Non-Bayesian intervals were more positive biased than negatively biased, that is, most intervals that did not contain the true value were greater than the true value. Some non-Bayesian methods had non-converging and inadmissible solutions for small samples and non-normal data. Bayesian empirical standard error estimates for informative and relatively less informative priors were closer to the average standard errors of the estimates. The coverage of Bayesian credibility intervals was closer to what was expected with overcoverage in a few cases. Although some Bayesian credibility intervals were wider, they reflected the nature of statistical uncertainty that comes with the data (e.g., small sample). Bayesian point estimates were also more accurate than non-Bayesian estimates. The results illustrate the importance of analyzing coverage and bias of interval estimates, and how ignoring interval estimates can be misleading

  4. Fast reactors as a solution for future small-scale nuclear energy

    International Nuclear Information System (INIS)

    Kudryavtseva, A.; Danilenko, K.; Dorofeev, K.

    2013-01-01

    Small nuclear power plants can provide a future platform for decentralized energy supply providing better levels of accessibility, safety and environmental friendliness. The optimal solution for SMR deployment is fast reactors with inherent safety. To compete alternative solutions SMRs must exhibit some evident advantages in: safety, technology, and economic. Small modular reactors with lead-bismuth coolant (SVBR-100) under development in Russia can be a prospective solution for future small and decentralized energy

  5. Small sample whole-genome amplification

    Science.gov (United States)

    Hara, Christine; Nguyen, Christine; Wheeler, Elizabeth; Sorensen, Karen; Arroyo, Erin; Vrankovich, Greg; Christian, Allen

    2005-11-01

    Many challenges arise when trying to amplify and analyze human samples collected in the field due to limitations in sample quantity, and contamination of the starting material. Tests such as DNA fingerprinting and mitochondrial typing require a certain sample size and are carried out in large volume reactions; in cases where insufficient sample is present whole genome amplification (WGA) can be used. WGA allows very small quantities of DNA to be amplified in a way that enables subsequent DNA-based tests to be performed. A limiting step to WGA is sample preparation. To minimize the necessary sample size, we have developed two modifications of WGA: the first allows for an increase in amplified product from small, nanoscale, purified samples with the use of carrier DNA while the second is a single-step method for cleaning and amplifying samples all in one column. Conventional DNA cleanup involves binding the DNA to silica, washing away impurities, and then releasing the DNA for subsequent testing. We have eliminated losses associated with incomplete sample release, thereby decreasing the required amount of starting template for DNA testing. Both techniques address the limitations of sample size by providing ample copies of genomic samples. Carrier DNA, included in our WGA reactions, can be used when amplifying samples with the standard purification method, or can be used in conjunction with our single-step DNA purification technique to potentially further decrease the amount of starting sample necessary for future forensic DNA-based assays.

  6. Small-scale engagement model with arrivals: analytical solutions

    International Nuclear Information System (INIS)

    Engi, D.

    1977-04-01

    This report presents an analytical model of small-scale battles. The specific impetus for this effort was provided by a need to characterize hypothetical battles between guards at a nuclear facility and their potential adversaries. The solution procedure can be used to find measures of a number of critical parameters; for example, the win probabilities and the expected duration of the battle. Numerical solutions are obtainable if the total number of individual combatants on the opposing sides is less than 10. For smaller force size battles, with one or two combatants on each side, symbolic solutions can be found. The symbolic solutions express the output parameters abstractly in terms of symbolic representations of the input parameters while the numerical solutions are expressed as numerical values. The input parameters are derived from the probability distributions of the attrition and arrival processes. The solution procedure reduces to solving sets of linear equations that have been constructed from the input parameters. The approach presented in this report does not address the problems associated with measuring the inputs. Rather, this report attempts to establish a relatively simple structure within which small-scale battles can be studied

  7. BioSAXS Sample Changer: a robotic sample changer for rapid and reliable high-throughput X-ray solution scattering experiments.

    Science.gov (United States)

    Round, Adam; Felisaz, Franck; Fodinger, Lukas; Gobbo, Alexandre; Huet, Julien; Villard, Cyril; Blanchet, Clement E; Pernot, Petra; McSweeney, Sean; Roessle, Manfred; Svergun, Dmitri I; Cipriani, Florent

    2015-01-01

    Small-angle X-ray scattering (SAXS) of macromolecules in solution is in increasing demand by an ever more diverse research community, both academic and industrial. To better serve user needs, and to allow automated and high-throughput operation, a sample changer (BioSAXS Sample Changer) that is able to perform unattended measurements of up to several hundred samples per day has been developed. The Sample Changer is able to handle and expose sample volumes of down to 5 µl with a measurement/cleaning cycle of under 1 min. The samples are stored in standard 96-well plates and the data are collected in a vacuum-mounted capillary with automated positioning of the solution in the X-ray beam. Fast and efficient capillary cleaning avoids cross-contamination and ensures reproducibility of the measurements. Independent temperature control for the well storage and for the measurement capillary allows the samples to be kept cool while still collecting data at physiological temperatures. The Sample Changer has been installed at three major third-generation synchrotrons: on the BM29 beamline at the European Synchrotron Radiation Facility (ESRF), the P12 beamline at the PETRA-III synchrotron (EMBL@PETRA-III) and the I22/B21 beamlines at Diamond Light Source, with the latter being the first commercial unit supplied by Bruker ASC.

  8. STATISTICAL EVALUATION OF SMALL SCALE MIXING DEMONSTRATION SAMPLING AND BATCH TRANSFER PERFORMANCE - 12093

    Energy Technology Data Exchange (ETDEWEB)

    GREER DA; THIEN MG

    2012-01-12

    The ability to effectively mix, sample, certify, and deliver consistent batches of High Level Waste (HLW) feed from the Hanford Double Shell Tanks (DST) to the Waste Treatment and Immobilization Plant (WTP) presents a significant mission risk with potential to impact mission length and the quantity of HLW glass produced. DOE's Tank Operations Contractor, Washington River Protection Solutions (WRPS) has previously presented the results of mixing performance in two different sizes of small scale DSTs to support scale up estimates of full scale DST mixing performance. Currently, sufficient sampling of DSTs is one of the largest programmatic risks that could prevent timely delivery of high level waste to the WTP. WRPS has performed small scale mixing and sampling demonstrations to study the ability to sufficiently sample the tanks. The statistical evaluation of the demonstration results which lead to the conclusion that the two scales of small DST are behaving similarly and that full scale performance is predictable will be presented. This work is essential to reduce the risk of requiring a new dedicated feed sampling facility and will guide future optimization work to ensure the waste feed delivery mission will be accomplished successfully. This paper will focus on the analytical data collected from mixing, sampling, and batch transfer testing from the small scale mixing demonstration tanks and how those data are being interpreted to begin to understand the relationship between samples taken prior to transfer and samples from the subsequent batches transferred. An overview of the types of data collected and examples of typical raw data will be provided. The paper will then discuss the processing and manipulation of the data which is necessary to begin evaluating sampling and batch transfer performance. This discussion will also include the evaluation of the analytical measurement capability with regard to the simulant material used in the demonstration tests. The

  9. Investigation of Phase Transition-Based Tethered Systems for Small Body Sample Capture

    Science.gov (United States)

    Quadrelli, Marco; Backes, Paul; Wilkie, Keats; Giersch, Lou; Quijano, Ubaldo; Scharf, Daniel; Mukherjee, Rudranarayan

    2009-01-01

    This paper summarizes the modeling, simulation, and testing work related to the development of technology to investigate the potential that shape memory actuation has to provide mechanically simple and affordable solutions for delivering assets to a surface and for sample capture and possible return to Earth. We investigate the structural dynamics and controllability aspects of an adaptive beam carrying an end-effector which, by changing equilibrium phases is able to actively decouple the end-effector dynamics from the spacecraft dynamics during the surface contact phase. Asset delivery and sample capture and return are at the heart of several emerging potential missions to small bodies, such as asteroids and comets, and to the surface of large bodies, such as Titan.

  10. ANL small-sample calorimeter system design and operation

    International Nuclear Information System (INIS)

    Roche, C.T.; Perry, R.B.; Lewis, R.N.; Jung, E.A.; Haumann, J.R.

    1978-07-01

    The Small-Sample Calorimetric System is a portable instrument designed to measure the thermal power produced by radioactive decay of plutonium-containing fuels. The small-sample calorimeter is capable of measuring samples producing power up to 32 milliwatts at a rate of one sample every 20 min. The instrument is contained in two packages: a data-acquisition module consisting of a microprocessor with an 8K-byte nonvolatile memory, and a measurement module consisting of the calorimeter and a sample preheater. The total weight of the system is 18 kg

  11. Using the multi-objective optimization replica exchange Monte Carlo enhanced sampling method for protein-small molecule docking.

    Science.gov (United States)

    Wang, Hongrui; Liu, Hongwei; Cai, Leixin; Wang, Caixia; Lv, Qiang

    2017-07-10

    In this study, we extended the replica exchange Monte Carlo (REMC) sampling method to protein-small molecule docking conformational prediction using RosettaLigand. In contrast to the traditional Monte Carlo (MC) and REMC sampling methods, these methods use multi-objective optimization Pareto front information to facilitate the selection of replicas for exchange. The Pareto front information generated to select lower energy conformations as representative conformation structure replicas can facilitate the convergence of the available conformational space, including available near-native structures. Furthermore, our approach directly provides min-min scenario Pareto optimal solutions, as well as a hybrid of the min-min and max-min scenario Pareto optimal solutions with lower energy conformations for use as structure templates in the REMC sampling method. These methods were validated based on a thorough analysis of a benchmark data set containing 16 benchmark test cases. An in-depth comparison between MC, REMC, multi-objective optimization-REMC (MO-REMC), and hybrid MO-REMC (HMO-REMC) sampling methods was performed to illustrate the differences between the four conformational search strategies. Our findings demonstrate that the MO-REMC and HMO-REMC conformational sampling methods are powerful approaches for obtaining protein-small molecule docking conformational predictions based on the binding energy of complexes in RosettaLigand.

  12. Sampling solution traces for the problem of sorting permutations by signed reversals

    Science.gov (United States)

    2012-01-01

    Background Traditional algorithms to solve the problem of sorting by signed reversals output just one optimal solution while the space of all optimal solutions can be huge. A so-called trace represents a group of solutions which share the same set of reversals that must be applied to sort the original permutation following a partial ordering. By using traces, we therefore can represent the set of optimal solutions in a more compact way. Algorithms for enumerating the complete set of traces of solutions were developed. However, due to their exponential complexity, their practical use is limited to small permutations. A partial enumeration of traces is a sampling of the complete set of traces and can be an alternative for the study of distinct evolutionary scenarios of big permutations. Ideally, the sampling should be done uniformly from the space of all optimal solutions. This is however conjectured to be ♯P-complete. Results We propose and evaluate three algorithms for producing a sampling of the complete set of traces that instead can be shown in practice to preserve some of the characteristics of the space of all solutions. The first algorithm (RA) performs the construction of traces through a random selection of reversals on the list of optimal 1-sequences. The second algorithm (DFALT) consists in a slight modification of an algorithm that performs the complete enumeration of traces. Finally, the third algorithm (SWA) is based on a sliding window strategy to improve the enumeration of traces. All proposed algorithms were able to enumerate traces for permutations with up to 200 elements. Conclusions We analysed the distribution of the enumerated traces with respect to their height and average reversal length. Various works indicate that the reversal length can be an important aspect in genome rearrangements. The algorithms RA and SWA show a tendency to lose traces with high average reversal length. Such traces are however rare, and qualitatively our results

  13. Local entropy as a measure for sampling solutions in constraint satisfaction problems

    International Nuclear Information System (INIS)

    Baldassi, Carlo; Ingrosso, Alessandro; Lucibello, Carlo; Saglietti, Luca; Zecchina, Riccardo

    2016-01-01

    We introduce a novel entropy-driven Monte Carlo (EdMC) strategy to efficiently sample solutions of random constraint satisfaction problems (CSPs). First, we extend a recent result that, using a large-deviation analysis, shows that the geometry of the space of solutions of the binary perceptron learning problem (a prototypical CSP), contains regions of very high-density of solutions. Despite being sub-dominant, these regions can be found by optimizing a local entropy measure. Building on these results, we construct a fast solver that relies exclusively on a local entropy estimate, and can be applied to general CSPs. We describe its performance not only for the perceptron learning problem but also for the random K-satisfiabilty problem (another prototypical CSP with a radically different structure), and show numerically that a simple zero-temperature Metropolis search in the smooth local entropy landscape can reach sub-dominant clusters of optimal solutions in a small number of steps, while standard Simulated Annealing either requires extremely long cooling procedures or just fails. We also discuss how the EdMC can heuristically be made even more efficient for the cases we studied. (paper: disordered systems, classical and quantum)

  14. Development of electric discharge equipment for small specimen sampling

    International Nuclear Information System (INIS)

    Okamoto, Koji; Kitagawa, Hideaki; Kusumoto, Junichi; Kanaya, Akihiro; Kobayashi, Toshimi

    2009-01-01

    We have developed the on-site electric discharge sampling equipment that can effectively take samples such as small specimens from the surface portion of the plant components. Compared with the conventional sampling equipment, our sampling equipment can take samples that are thinner in depth and larger in area. In addition, the affection to the equipment can be held down to the minimum, and the thermally-affected zone of the material due to electric discharge is small, which is to be ignored. Therefore, our equipment is excellent in taking samples for various tests such as residual life evaluation.

  15. Small angle neutron scattering by polymer solutions

    International Nuclear Information System (INIS)

    Farnoux, B.; Jannink, G.

    1980-08-01

    Small angle neutron scattering is an experimental technique introduced since about 10 years for the observation of the polymer conformation in all the concentration range from dilute solution to the melt. After a brief recall of the elementary relations between scattering amplitude, index of refraction and scattered intensity, two concepts related to this last quantity (the contrast and the pair correlation function) are discussed in details

  16. Rapid Resuscitation with Small Volume Hypertonic Saline Solution ...

    African Journals Online (AJOL)

    Rapid Resuscitation with Small Volume Hypertonic Saline Solution for Patients in Traumatic Haemorrhagic Shock. ... The data were entered into a computer data base and analysed. Results: Forty five patients were enrolled and resuscitated with 250 mls 7.5% HSS. Among the studied patients, 88.9% recovered from shock ...

  17. Accelerator mass spectrometry of small biological samples.

    Science.gov (United States)

    Salehpour, Mehran; Forsgard, Niklas; Possnert, Göran

    2008-12-01

    Accelerator mass spectrometry (AMS) is an ultra-sensitive technique for isotopic ratio measurements. In the biomedical field, AMS can be used to measure femtomolar concentrations of labeled drugs in body fluids, with direct applications in early drug development such as Microdosing. Likewise, the regenerative properties of cells which are of fundamental significance in stem-cell research can be determined with an accuracy of a few years by AMS analysis of human DNA. However, AMS nominally requires about 1 mg of carbon per sample which is not always available when dealing with specific body substances such as localized, organ-specific DNA samples. Consequently, it is of analytical interest to develop methods for the routine analysis of small samples in the range of a few tens of microg. We have used a 5 MV Pelletron tandem accelerator to study small biological samples using AMS. Different methods are presented and compared. A (12)C-carrier sample preparation method is described which is potentially more sensitive and less susceptible to contamination than the standard procedures.

  18. Influence of multiple well defined conformations on small-angle scattering of proteins in solution.

    Science.gov (United States)

    Heller, William T

    2005-01-01

    A common structural motif for many proteins comprises rigid domains connected by a flexible hinge or linker. The flexibility afforded by these domains is important for proper function and such proteins may be able to adopt more than one conformation in solution under equilibrium conditions. Small-angle scattering of proteins in solution samples all conformations that exist in the sampled volume during the time of the measurement, providing an ensemble-averaged intensity. In this paper, the influence of sampling an ensemble of well defined protein structures on the small-angle solution scattering intensity profile is examined through common analysis methods. Two tests were performed using simulated data: one with the extended and collapsed states of the bilobal calcium-binding protein calmodulin and the second with the catalytic subunit of protein kinase A, which has two globular domains connected by a glycine hinge. In addition to analyzing the simulated data for the radii of gyration Rg, distance distribution function P(r) and particle volume, shape restoration was applied to the simulated data. Rg and P(r) of the ensemble profiles could be easily mistaken for a single intermediate state. The particle volumes and models of the ensemble intensity profiles show that some indication of multiple conformations exists in the case of calmodulin, which manifests an enlarged volume and shapes that are clear superpositions of the conformations used. The effect on the structural parameters and models is much more subtle in the case of the catalytic subunit of protein kinase A. Examples of how noise influences the data and analyses are also presented. These examples demonstrate the loss of the indications of multiple conformations in cases where even broad distributions of structures exist. While the tests using calmodulin show that the ensemble states remain discernible from the other ensembles tested or a single partially collapsed state, the tests performed using the

  19. Modeling and Testing of Phase Transition-Based Deployable Systems for Small Body Sample Capture

    Science.gov (United States)

    Quadrelli, Marco; Backes, Paul; Wilkie, Keats; Giersch, Lou; Quijano, Ubaldo; Keim, Jason; Mukherjee, Rudranarayan

    2009-01-01

    This paper summarizes the modeling, simulation, and testing work related to the development of technology to investigate the potential that shape memory actuation has to provide mechanically simple and affordable solutions for delivering assets to a surface and for sample capture and return. We investigate the structural dynamics and controllability aspects of an adaptive beam carrying an end-effector which, by changing equilibrium phases is able to actively decouple the end-effector dynamics from the spacecraft dynamics during the surface contact phase. Asset delivery and sample capture and return are at the heart of several emerging potential missions to small bodies, such as asteroids and comets, and to the surface of large bodies, such as Titan.

  20. Estimation for small domains in double sampling for stratification ...

    African Journals Online (AJOL)

    In this article, we investigate the effect of randomness of the size of a small domain on the precision of an estimator of mean for the domain under double sampling for stratification. The result shows that for a small domain that cuts across various strata with unknown weights, the sampling variance depends on the within ...

  1. Structure of fullerene aggregates in pyridine/water solutions by small-angle neutron scattering

    International Nuclear Information System (INIS)

    Aksenov, V.L.; Belushkin, A.V.; Avdeev, M.V.; Rosta, L.; Mihailovic, D.; Mrzel, A.; Serdyuk, I.N.; Timchenko, A.A.

    2001-01-01

    Results of small-angle neutron scattering experiments on fullerenes (C 60 ) in pyridine/water solutions are reported. They confirm conclusions of the previous studies, in particular, dynamic light scattering experiments. Aggregates with characteristic radius of about 20 nm are formed in the solutions. The contrast variation using different combinations of protonated/deuterated components (water and pyridine) of the solutions points to the small pyridine content inside the aggregates. This fact testifies that the aggregates consist of a massive fullerene core covered by a thin pyridine shell

  2. Solution-processed white organic light-emitting devices based on small-molecule materials

    International Nuclear Information System (INIS)

    Wang Dongdong; Wu Zhaoxin; Zhang Xinwen; Wang Dawei; Hou Xun

    2010-01-01

    We investigated solution-processed films of 4,4'-bis(2,2-diphenylvinyl)-1,1'-bibenyl (DPVBi) and its blends with N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TPD) by atomic force microscopy (AFM). The AFM result shows that the solution-processed films are pin-free and their morphology is smooth enough to be used in OLEDs. We have developed a solution-processed white organic light-emitting device (WOLEDs) based on small-molecules, in which the light-emitting layer (EML) was formed by spin-coating the solution of small-molecules on top of the solution-processed hole-transporting layer. This WOLEDs, in which the EML consists of co-host (DPVBi and TPD), the blue dopant (4,4'-bis[2-(4-(N,N-diphenylamino)phenyl)vinyl]biphenyl) and the yellow dye (5,6,11,12-tetraphenylnaphtacene), has a current efficiency of 6.0 cd/A at a practical luminance of 1000 cd/m 2 , a maximum luminance of 22500 cd/m 2 , and its color coordinates are quite stable. Our research shows a possible approach to achieve efficient and low-cost small-molecule-based WOLEDs, which avoids the complexities of the co-evaporation process of multiple dopants and host materials in vacuum depositions.

  3. Small-angle X-ray scattering of solutions

    International Nuclear Information System (INIS)

    Koch, M.H.J.; Stuhrmann, H.B.; Vachette, P.; Tardieu, A.

    1982-01-01

    The use of synchrotron radiation in small-angle X-ray scattering (SAXS) techniques in biological structural studies is described. The main features of the monochromatic radiation systems and the white radiation systems are considered. The detectors, data acquisition and experimental procedures are briefly described. Experimental results are presented for 1) measurements on dilute solutions and weak scatterers, 2) measurement of conformational transitions, 3) contrast variation experiments, 4) time-resolved measurements and 5) complex contrast variation. (U.K.)

  4. Pulsed Direct Current Electrospray: Enabling Systematic Analysis of Small Volume Sample by Boosting Sample Economy.

    Science.gov (United States)

    Wei, Zhenwei; Xiong, Xingchuang; Guo, Chengan; Si, Xingyu; Zhao, Yaoyao; He, Muyi; Yang, Chengdui; Xu, Wei; Tang, Fei; Fang, Xiang; Zhang, Sichun; Zhang, Xinrong

    2015-11-17

    We had developed pulsed direct current electrospray ionization mass spectrometry (pulsed-dc-ESI-MS) for systematically profiling and determining components in small volume sample. Pulsed-dc-ESI utilized constant high voltage to induce the generation of single polarity pulsed electrospray remotely. This method had significantly boosted the sample economy, so as to obtain several minutes MS signal duration from merely picoliter volume sample. The elongated MS signal duration enable us to collect abundant MS(2) information on interested components in a small volume sample for systematical analysis. This method had been successfully applied for single cell metabolomics analysis. We had obtained 2-D profile of metabolites (including exact mass and MS(2) data) from single plant and mammalian cell, concerning 1034 components and 656 components for Allium cepa and HeLa cells, respectively. Further identification had found 162 compounds and 28 different modification groups of 141 saccharides in a single Allium cepa cell, indicating pulsed-dc-ESI a powerful tool for small volume sample systematical analysis.

  5. [Progress in sample preparation and analytical methods for trace polar small molecules in complex samples].

    Science.gov (United States)

    Zhang, Qianchun; Luo, Xialin; Li, Gongke; Xiao, Xiaohua

    2015-09-01

    Small polar molecules such as nucleosides, amines, amino acids are important analytes in biological, food, environmental, and other fields. It is necessary to develop efficient sample preparation and sensitive analytical methods for rapid analysis of these polar small molecules in complex matrices. Some typical materials in sample preparation, including silica, polymer, carbon, boric acid and so on, are introduced in this paper. Meanwhile, the applications and developments of analytical methods of polar small molecules, such as reversed-phase liquid chromatography, hydrophilic interaction chromatography, etc., are also reviewed.

  6. Integrating sphere based reflectance measurements for small-area semiconductor samples

    Science.gov (United States)

    Saylan, S.; Howells, C. T.; Dahlem, M. S.

    2018-05-01

    This article describes a method that enables reflectance spectroscopy of small semiconductor samples using an integrating sphere, without the use of additional optical elements. We employed an inexpensive sample holder to measure the reflectance of different samples through 2-, 3-, and 4.5-mm-diameter apertures and applied a mathematical formulation to remove the bias from the measured spectra caused by illumination of the holder. Using the proposed method, the reflectance of samples fabricated using expensive or rare materials and/or low-throughput processes can be measured. It can also be incorporated to infer the internal quantum efficiency of small-area, research-level solar cells. Moreover, small samples that reflect light at large angles and develop scattering may also be measured reliably, by virtue of an integrating sphere insensitive to directionalities.

  7. Decision Support on Small size Passive Samples

    Directory of Open Access Journals (Sweden)

    Vladimir Popukaylo

    2018-05-01

    Full Text Available A construction technique of adequate mathematical models for small size passive samples, in conditions when classical probabilistic-statis\\-tical methods do not allow obtaining valid conclusions was developed.

  8. Consensus of heterogeneous multi-agent systems based on sampled data with a small sampling delay

    International Nuclear Information System (INIS)

    Wang Na; Wu Zhi-Hai; Peng Li

    2014-01-01

    In this paper, consensus problems of heterogeneous multi-agent systems based on sampled data with a small sampling delay are considered. First, a consensus protocol based on sampled data with a small sampling delay for heterogeneous multi-agent systems is proposed. Then, the algebra graph theory, the matrix method, the stability theory of linear systems, and some other techniques are employed to derive the necessary and sufficient conditions guaranteeing heterogeneous multi-agent systems to asymptotically achieve the stationary consensus. Finally, simulations are performed to demonstrate the correctness of the theoretical results. (interdisciplinary physics and related areas of science and technology)

  9. Electroerosion of metal in aqueous solution for sample introduction into an inductively coupled plasma mass spectrometer

    International Nuclear Information System (INIS)

    Goltz, Douglas; Boileau, Michael; Reinfelds, Gundars

    2003-01-01

    When high current (1-10 A cm -2 ) is applied between two conductive samples (metals) in aqueous solution, electroerosion occurs on the surface as a result of electrolysis and possibly collisions of dissolved ions with the metal surface. The power supply for the electroerosion apparatus in this work was a modified spark source unit. Current could be varied in intervals of 2.5, 5 and 10 A in either half-wave (unipolar) or full-wave (bipolar) output. The electroeroded metal forms a colloidal suspension in aqueous solution with particle sizes of the order of 1-10 μm and possibly larger. The suspension is readily dissolved using a small amount (100 μl) of concentrated acid (HCl or HNO 3 ) prior to analysis. Electroerosion of steel and brass in aqueous solution is described both for rapid sample dissolution and as a solid sampling approach for ICP-MS. Some of the electroerosion properties described in this paper include rates of erosion as a function of gap between the conductive samples and solution conductivity. Rates of electroerosion decreased from 120 to 30 μg s -1 as the gap was increased from 2 to 5 mm. Rates of electroerosion also increased significantly from 200 to 1000 μg s -1 as the conductivity of the electroerosion solution increased from 0.01 to 0.05 M NaCl. Interfacing the electroerosion apparatus to an ICP-MS was straight forward, as no special equipment was required. Therefore, the electroerosion apparatus can be used for rapid 'on-line' sample dissolution prior to introduction into an ICP. ICP-MS time profiles of selected metals in stainless steel 308L illustrate the behavior of 52 Cr + , 55 Mn + and 60 Ni + during a typical electroerosion cycle. Aspiration of the colloidal suspension into the ICP did not appear to load the plasma significantly, however, all of the metals produced noisy signals (±10%). A glass concentric nebulizer was used without clogging, so it is likely that the heterogeneous nature of the colloidal suspension caused this effect

  10. Electroerosion of metal in aqueous solution for sample introduction into an inductively coupled plasma mass spectrometer

    Science.gov (United States)

    Goltz, Douglas; Boileau, Michael; Reinfelds, Gundars

    2003-07-01

    When high current (1-10 A cm -2) is applied between two conductive samples (metals) in aqueous solution, electroerosion occurs on the surface as a result of electrolysis and possibly collisions of dissolved ions with the metal surface. The power supply for the electroerosion apparatus in this work was a modified spark source unit. Current could be varied in intervals of 2.5, 5 and 10 A in either half-wave (unipolar) or full-wave (bipolar) output. The electroeroded metal forms a colloidal suspension in aqueous solution with particle sizes of the order of 1-10 μm and possibly larger. The suspension is readily dissolved using a small amount (100 μl) of concentrated acid (HCl or HNO 3) prior to analysis. Electroerosion of steel and brass in aqueous solution is described both for rapid sample dissolution and as a solid sampling approach for ICP-MS. Some of the electroerosion properties described in this paper include rates of erosion as a function of gap between the conductive samples and solution conductivity. Rates of electroerosion decreased from 120 to 30 μg s -1 as the gap was increased from 2 to 5 mm. Rates of electroerosion also increased significantly from 200 to 1000 μg s -1 as the conductivity of the electroerosion solution increased from 0.01 to 0.05 M NaCl. Interfacing the electroerosion apparatus to an ICP-MS was straight forward, as no special equipment was required. Therefore, the electroerosion apparatus can be used for rapid 'on-line' sample dissolution prior to introduction into an ICP. ICP-MS time profiles of selected metals in stainless steel 308L illustrate the behavior of 52Cr +, 55Mn + and 60Ni + during a typical electroerosion cycle. Aspiration of the colloidal suspension into the ICP did not appear to load the plasma significantly, however, all of the metals produced noisy signals (±10%). A glass concentric nebulizer was used without clogging, so it is likely that the heterogeneous nature of the colloidal suspension caused this effect.

  11. INNOVATIVE SOLUTIONS FOR SMALL SCALE VERTICAL AXIS WIND TURBINES USED IN HARBOURS AND SHORE AREAS

    Directory of Open Access Journals (Sweden)

    IONESCU Raluca Dora

    2014-09-01

    Full Text Available The paper aims to analyse the wind turbine solutions implemented in harbours and on shore areas. Also a thorough study of the blade design solutions for small power Vertical axis wind turbines (VAWTs has been conducted, with their advantages and disadvantages, in order to find the best solution that minimises the loads and helps with the self-starting capabilities of the wind turbine. First are presented all the solutions, next are discussed several research results for each solution and, in the end, a combination of solutions is chosen for our new small power VAWT with a pre-dimensioning analysis.

  12. Small Scale Mixing Demonstration Batch Transfer and Sampling Performance of Simulated HLW - 12307

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Jesse; Townson, Paul; Vanatta, Matt [EnergySolutions, Engineering and Technology Group, Richland, WA, 99354 (United States)

    2012-07-01

    The ability to effectively mix, sample, certify, and deliver consistent batches of High Level Waste (HLW) feed from the Hanford Double Shell Tanks (DST) to the Waste treatment Plant (WTP) has been recognized as a significant mission risk with potential to impact mission length and the quantity of HLW glass produced. At the end of 2009 DOE's Tank Operations Contractor, Washington River Protection Solutions (WRPS), awarded a contract to EnergySolutions to design, fabricate and operate a demonstration platform called the Small Scale Mixing Demonstration (SSMD) to establish pre-transfer sampling capacity, and batch transfer performance data at two different scales. This data will be used to examine the baseline capacity for a tank mixed via rotational jet mixers to transfer consistent or bounding batches, and provide scale up information to predict full scale operational performance. This information will then in turn be used to define the baseline capacity of such a system to transfer and sample batches sent to WTP. The Small Scale Mixing Demonstration (SSMD) platform consists of 43'' and 120'' diameter clear acrylic test vessels, each equipped with two scaled jet mixer pump assemblies, and all supporting vessels, controls, services, and simulant make up facilities. All tank internals have been modeled including the air lift circulators (ALCs), the steam heating coil, and the radius between the wall and floor. The test vessels are set up to simulate the transfer of HLW out of a mixed tank, and collect a pre-transfer sample in a manner similar to the proposed baseline configuration. The collected material is submitted to an NQA-1 laboratory for chemical analysis. Previous work has been done to assess tank mixing performance at both scales. This work involved a combination of unique instruments to understand the three dimensional distribution of solids using a combination of Coriolis meter measurements, in situ chord length distribution

  13. Normal solutions of the Boltzmann equation with small Knudsen number

    International Nuclear Information System (INIS)

    Ding, E.J.; Huang, Z.Q.

    1986-01-01

    A singular perturbation method is used to find the normal solutions of the Boltzmann equation with small Knudsen number. It is proved that the secular terms may be removed by improving the Hilbert expansion and the Enskog expansion

  14. Multi-element analysis of small biological samples

    International Nuclear Information System (INIS)

    Rokita, E.; Cafmeyer, J.; Maenhaut, W.

    1983-01-01

    A method combining PIXE and INAA was developed to determine the elemental composition of small biological samples. The method needs virtually no sample preparation and less than 1 mg is sufficient for the analysis. The method was used for determining up to 18 elements in leaves taken from Cracow Herbaceous. The factors which influence the elemental composition of leaves and the possible use of leaves as an environmental pollution indicator are discussed

  15. Mechanical characteristics of historic mortars from tests on small-sample non-standard on small-sample non-standard specimens

    Czech Academy of Sciences Publication Activity Database

    Drdácký, Miloš; Slížková, Zuzana

    2008-01-01

    Roč. 17, č. 1 (2008), s. 20-29 ISSN 1407-7353 R&D Projects: GA ČR(CZ) GA103/06/1609 Institutional research plan: CEZ:AV0Z20710524 Keywords : small-sample non-standard testing * lime * historic mortar Subject RIV: AL - Art, Architecture, Cultural Heritage

  16. Peritoneal fluid transport in CAPD patients with different transport rates of small solutes.

    Science.gov (United States)

    Sobiecka, Danuta; Waniewski, Jacek; Weryński, Andrzej; Lindholm, Bengt

    2004-01-01

    Continuous ambulatory peritoneal dialysis (CAPD) patients with high peritoneal solute transport rate often have inadequate peritoneal fluid transport. It is not known whether this inadequate fluid transport is due solely to a too rapid fall of osmotic pressure, or if the decreased effectiveness of fluid transport is also a contributing factor. To analyze fluid transport parameters and the effectiveness of dialysis fluid osmotic pressure in the induction of fluid flow in CAPD patients with different small solute transport rates. 44 CAPD patients were placed in low (n = 6), low-average (n = 13), high-average (n = 19), and high (n = 6) transport groups according to a modified peritoneal equilibration test (PET). The study involved a 6-hour peritoneal dialysis dwell with 2 L 3.86% glucose dialysis fluid for each patient. Radioisotopically labeled serum albumin was added as a volume marker.The fluid transport parameters (osmotic conductance and fluid absorption rate) were estimated using three mathematical models of fluid transport: (1) Pyle model (model P), which describes ultrafiltration rate as an exponential function of time; (2) model OS, which is based on the linear relationship of ultrafiltration rate and overall osmolality gradient between dialysis fluid and blood; and (3) model G, which is based on the linear relationship between ultrafiltration rate and glucose concentration gradient between dialysis fluid and blood. Diffusive mass transport coefficients (K(BD)) for glucose, urea, creatinine, potassium, and sodium were estimated using the modified Babb-Randerson-Farrell model. The high transport group had significantly lower dialysate volume and glucose and osmolality gradients between dialysate and blood, but significantly higher K(BD) for small solutes compared with the other transport groups. Osmotic conductance, fluid absorption rate, and initial ultrafiltration rate did not differ among the transport groups for model OS and model P. Model G yielded

  17. Exploratory Factor Analysis With Small Samples and Missing Data.

    Science.gov (United States)

    McNeish, Daniel

    2017-01-01

    Exploratory factor analysis (EFA) is an extremely popular method for determining the underlying factor structure for a set of variables. Due to its exploratory nature, EFA is notorious for being conducted with small sample sizes, and recent reviews of psychological research have reported that between 40% and 60% of applied studies have 200 or fewer observations. Recent methodological studies have addressed small size requirements for EFA models; however, these models have only considered complete data, which are the exception rather than the rule in psychology. Furthermore, the extant literature on missing data techniques with small samples is scant, and nearly all existing studies focus on topics that are not of primary interest to EFA models. Therefore, this article presents a simulation to assess the performance of various missing data techniques for EFA models with both small samples and missing data. Results show that deletion methods do not extract the proper number of factors and estimate the factor loadings with severe bias, even when data are missing completely at random. Predictive mean matching is the best method overall when considering extracting the correct number of factors and estimating factor loadings without bias, although 2-stage estimation was a close second.

  18. Global existence of small solutions to semilinear Schroedinger equations

    International Nuclear Information System (INIS)

    Chihara, Hiroyuki

    1996-01-01

    We present global existence theorem for semilinear Schrodinger equations. In general, Schrodinger-type equations do not admit the classical energy estimates. To avoid this difficulty, we use S. Doi's method for linear Schrodinger-type equations. Combining his method and L p -L q estimates, we prove the global existence of solutions with small initial data

  19. Evaluation of energy deposition by 153Sm in small samples

    International Nuclear Information System (INIS)

    Cury, M.I.C.; Siqueira, P.T.D.; Yoriyaz, H.; Coelho, P.R.P.; Da Silva, M.A.; Okazaki, K.

    2002-01-01

    Aim: This work presents evaluations of the absorbed dose by 'in vitro' blood cultures when mixed with 153 Sm solutions of different concentrations. Although 153 Sm is used as radiopharmaceutical mainly due to its beta emission, which is short-range radiation, it also emits gamma radiation which has a longer-range penetration. Therefore it turns to be a difficult task to determine the absorbed dose by small samples where the infinite approximation is no longer valid. Materials and Methods: MCNP-4C (Monte Carlo N - Particle transport code) has been used to perform the evaluations. It is not a deterministic code that calculates the value of a specific quantity solving the physical equations involved in the problem, but a virtual experiment where the events related to the problems are simulated and the concerned quantities are tallied. MCNP also stands out by its possibilities to specify geometrically any problem. However, these features, among others, turns MCNP in a time consuming code. The simulated problem consists of a cylindrical plastic tube with 1.5 cm internal diameter and 0.1cm thickness. It also has 2.0 cm height conic bottom end, so that the represented sample has 4.0 ml ( consisted by 1 ml of blood and 3 ml culture medium). To evaluate the energy deposition in the blood culture in each 153 Sm decay, the problem has been divided in 3 steps to account to the β- emissions (which has a continuum spectrum), gammas and conversion and Auger electrons emissions. Afterwards each emission contribution was weighted and summed to present the final value. Besides this radiation 'fragmentation', simulations were performed for many different amounts of 153 Sm solution added to the sample. These amounts cover a range from 1μl to 0.5 ml. Results: The average energy per disintegration of 153 Sm is 331 keV [1]. Gammas account for 63 keV and β-, conversion and Auger electrons account for 268 keV. The simulations performed showed an average energy deposition of 260 ke

  20. Testing of Small Graphite Samples for Nuclear Qualification

    Energy Technology Data Exchange (ETDEWEB)

    Julie Chapman

    2010-11-01

    Accurately determining the mechanical properties of small irradiated samples is crucial to predicting the behavior of the overal irradiated graphite components within a Very High Temperature Reactor. The sample size allowed in a material test reactor, however, is limited, and this poses some difficulties with respect to mechanical testing. In the case of graphite with a larger grain size, a small sample may exhibit characteristics not representative of the bulk material, leading to inaccuracies in the data. A study to determine a potential size effect on the tensile strength was pursued under the Next Generation Nuclear Plant program. It focuses first on optimizing the tensile testing procedure identified in the American Society for Testing and Materials (ASTM) Standard C 781-08. Once the testing procedure was verified, a size effect was assessed by gradually reducing the diameter of the specimens. By monitoring the material response, a size effect was successfully identified.

  1. OPC Paste Samples Exposed To Aggressive Solutions. Cementitious Barriers Partnership

    Energy Technology Data Exchange (ETDEWEB)

    Langton, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2014-11-01

    The study presented in this report focused on a low-activity wasteform containing a high-pH pore solution with a significant level of sulfate. The purpose of the study was to improve understanding of the complex concrete/wasteform reactive transport problem, in particular, the role of pH in sulfate attack. Paste samples prepared at three different water-to-cement ratios were tested. The mixtures were prepared with ASTM Type I cement, without additional admixtures. The samples were exposed to two different sodium sulfate contact solutions. The first solution was prepared at 0.15M Na2SO4. The second solution also incorporated 0.5M NaOH, to mimic the high pH conditions found in Saltstone. The data collected indicated that, in Na2SO4 solution, damage occurs to the pastes. In the case of the high-pH sulfate solution (Na2SO4 + NaOH), no signs of damage were observed on any of the paste mixtures. These results indicate that the high sulfate content found in the wasteform pore solution will not necessarily lead to severe damage to concrete. Good-quality mixtures could thus prove durable over the long term, and act as an effective barrier to prevent radionuclides from reaching the environment.

  2. Considerable improvement in the stability of solution processed small molecule OLED by annealing

    Energy Technology Data Exchange (ETDEWEB)

    Mao Guilin [Key Laboratory of Photonics Technology for Information, Key Laboratory for Physical Electronics and Devices of the Ministry of Education, School of Electronic and Information Engineering, Xi' an Jiaotong University, Xi' an, 710049 (China); Wu Zhaoxin, E-mail: zhaoxinwu@mail.xjtu.edu.cn [Key Laboratory of Photonics Technology for Information, Key Laboratory for Physical Electronics and Devices of the Ministry of Education, School of Electronic and Information Engineering, Xi' an Jiaotong University, Xi' an, 710049 (China); He Qiang [Key Laboratory of Photonics Technology for Information, Key Laboratory for Physical Electronics and Devices of the Ministry of Education, School of Electronic and Information Engineering, Xi' an Jiaotong University, Xi' an, 710049 (China); Department of UAV, Wuhan Ordnance Noncommissioned Officers Academy, Wuhan, 430075 (China); Jiao Bo; Xu Guojin; Hou Xun [Key Laboratory of Photonics Technology for Information, Key Laboratory for Physical Electronics and Devices of the Ministry of Education, School of Electronic and Information Engineering, Xi' an Jiaotong University, Xi' an, 710049 (China); Chen Zhijian; Gong Qihuang [State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing, 100871 (China)

    2011-06-15

    We investigated the annealing effect on solution processed small organic molecule organic films, which were annealed with various conditions. It was found that the densities of the spin-coated (SC) films increased and the surface roughness decreased as the annealing temperature rose. We fabricated corresponding organic light emitting diodes (OLEDs) by spin coating on the same annealing conditions. The solution processed OLEDs show the considerable efficiency and stability, which were prior or equivalent to the vacuum-deposited (VD) counterparts. Our research shows that annealing process plays a key role in prolonging the lifetime of solution processed small molecule OLEDs, and the mechanism for the improvement of the device performance upon annealing was also discussed.

  3. Electroerosion of metal in aqueous solution for sample introduction into an inductively coupled plasma mass spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Goltz, Douglas E-mail: dgoltz@uwinnipeg.ca; Boileau, Michael; Reinfelds, Gundars

    2003-07-18

    When high current (1-10 A cm{sup -2}) is applied between two conductive samples (metals) in aqueous solution, electroerosion occurs on the surface as a result of electrolysis and possibly collisions of dissolved ions with the metal surface. The power supply for the electroerosion apparatus in this work was a modified spark source unit. Current could be varied in intervals of 2.5, 5 and 10 A in either half-wave (unipolar) or full-wave (bipolar) output. The electroeroded metal forms a colloidal suspension in aqueous solution with particle sizes of the order of 1-10 {mu}m and possibly larger. The suspension is readily dissolved using a small amount (100 {mu}l) of concentrated acid (HCl or HNO{sub 3}) prior to analysis. Electroerosion of steel and brass in aqueous solution is described both for rapid sample dissolution and as a solid sampling approach for ICP-MS. Some of the electroerosion properties described in this paper include rates of erosion as a function of gap between the conductive samples and solution conductivity. Rates of electroerosion decreased from 120 to 30 {mu}g s{sup -1} as the gap was increased from 2 to 5 mm. Rates of electroerosion also increased significantly from 200 to 1000 {mu}g s{sup -1} as the conductivity of the electroerosion solution increased from 0.01 to 0.05 M NaCl. Interfacing the electroerosion apparatus to an ICP-MS was straight forward, as no special equipment was required. Therefore, the electroerosion apparatus can be used for rapid 'on-line' sample dissolution prior to introduction into an ICP. ICP-MS time profiles of selected metals in stainless steel 308L illustrate the behavior of {sup 52}Cr{sup +}, {sup 55}Mn{sup +} and {sup 60}Ni{sup +} during a typical electroerosion cycle. Aspiration of the colloidal suspension into the ICP did not appear to load the plasma significantly, however, all of the metals produced noisy signals ({+-}10%). A glass concentric nebulizer was used without clogging, so it is likely that the

  4. Removal of fission products from waste solutions using 16 different soil samples

    International Nuclear Information System (INIS)

    Bangash, M.A.; Hanif, J.

    1997-01-01

    Most of the nuclear sites use pits in the surrounding soils for the storage/disposal of low active waste (LAW) solutions. The characteristics of the soil if not suitable for the fixation or adsorption of the radioactive nuclides, may cause migration of these nuclides to hydrosphere. The phenomenon has the risk of radio toxic pollution for the living bodies therefore minerals composing the soil and their adsorption properties need to be investigated. For this purpose 16 different soil samples were collected from all over Pakistan. Mineralogical composition of the soils was determined by X-ray diffraction analysis. It was found that most of the samples contained clay minerals, illite, kaolinite and montmorillonite. Studies for the removal of fission products like, /sup 137/Cs. /sup 60/Sr and activation product /sup 60/CO from solution were carried out on these samples. The sorption experiments were performed by batch technique using radioactive as tracers. Distribution co-efficient were determined by mixing he element solution at pH 3 with the soil at soil solution ratios of 1 to 20. It is revealed from the experimental data that efficient removal of fission products from solutions is achieved by soil samples containing clay mineral montmorillonite, followed by little and kaolinite. These soils thus can be effectively used for the disposal of low level radioactive waste solutions without causing any environmental hazard. (author)

  5. Combination of acoustic levitation with small angle scattering techniques and synchrotron radiation circular dichroism. Application to the study of protein solutions.

    Science.gov (United States)

    Cristiglio, Viviana; Grillo, Isabelle; Fomina, Margarita; Wien, Frank; Shalaev, Evgenyi; Novikov, Alexey; Brassamin, Séverine; Réfrégiers, Matthieu; Pérez, Javier; Hennet, Louis

    2017-01-01

    The acoustic levitation technique is a useful sample handling method for small solid and liquids samples, suspended in air by means of an ultrasonic field. This method was previously used at synchrotron sources for studying pharmaceutical liquids and protein solutions using x-ray diffraction and small angle x-ray scattering (SAXS). In this work we combined for the first time this containerless method with small angle neutron scattering (SANS) and synchrotron radiation circular dichroism (SRCD) to study the structural behavior of proteins in solutions during the water evaporation. SANS results are also compared with SAXS experiments. The aggregation behavior of 45μl droplets of lysozyme protein diluted in water was followed during the continuous increase of the sample concentration by evaporating the solvent. The evaporation kinetics was followed at different drying stage by SANS and SAXS with a good data quality. In a prospective work using SRCD, we also studied the evolution of the secondary structure of the myoglobin protein in water solution in the same evaporation conditions. Acoustic levitation was applied for the first time with SANS and the high performances of the used neutron instruments made it possible to monitor fast container-less reactions in situ. A preliminary work using SRCD shows the potentiality of its combination with acoustic levitation for studying the evolution of the protein structure with time. This multi-techniques approach could give novel insights into crystallization and self-assembly phenomena of biological compound with promising potential applications in pharmaceutical, food and cosmetics industry. This article is part of a Special Issue entitled "Science for Life" Guest Editor: Dr. Austen Angell, Dr. Salvatore Magazù and Dr. Federica Migliardo. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Small sample GEE estimation of regression parameters for longitudinal data.

    Science.gov (United States)

    Paul, Sudhir; Zhang, Xuemao

    2014-09-28

    Longitudinal (clustered) response data arise in many bio-statistical applications which, in general, cannot be assumed to be independent. Generalized estimating equation (GEE) is a widely used method to estimate marginal regression parameters for correlated responses. The advantage of the GEE is that the estimates of the regression parameters are asymptotically unbiased even if the correlation structure is misspecified, although their small sample properties are not known. In this paper, two bias adjusted GEE estimators of the regression parameters in longitudinal data are obtained when the number of subjects is small. One is based on a bias correction, and the other is based on a bias reduction. Simulations show that the performances of both the bias-corrected methods are similar in terms of bias, efficiency, coverage probability, average coverage length, impact of misspecification of correlation structure, and impact of cluster size on bias correction. Both these methods show superior properties over the GEE estimates for small samples. Further, analysis of data involving a small number of subjects also shows improvement in bias, MSE, standard error, and length of the confidence interval of the estimates by the two bias adjusted methods over the GEE estimates. For small to moderate sample sizes (N ≤50), either of the bias-corrected methods GEEBc and GEEBr can be used. However, the method GEEBc should be preferred over GEEBr, as the former is computationally easier. For large sample sizes, the GEE method can be used. Copyright © 2014 John Wiley & Sons, Ltd.

  7. Quantification of RNA in bacteriophage MS2-like viruses in solution by small-angle X-ray scattering

    International Nuclear Information System (INIS)

    Kuzmanovic, Deborah A.; Elashvili, Ilya; Wick, Charles; O'Connell, Catherine; Krueger, Susan

    2006-01-01

    Recombinant forms of bacteriophage MS2 virus particles, wild-type MS2 and MS2 capsids have been examined in solution using small-angle X-ray scattering (SAXS). SAXS was used to determine the overall size of the virus particles and to quantify the amount of encapsulated viral RNA. These studies show that analysis of natural and recombinant forms of MS2 virus by SAXS can be used as both a quantitative measure of nucleic acid content in situ and diagnostic indicator of sample integrity

  8. Accurate EPR radiosensitivity calibration using small sample masses

    Science.gov (United States)

    Hayes, R. B.; Haskell, E. H.; Barrus, J. K.; Kenner, G. H.; Romanyukha, A. A.

    2000-03-01

    We demonstrate a procedure in retrospective EPR dosimetry which allows for virtually nondestructive sample evaluation in terms of sample irradiations. For this procedure to work, it is shown that corrections must be made for cavity response characteristics when using variable mass samples. Likewise, methods are employed to correct for empty tube signals, sample anisotropy and frequency drift while considering the effects of dose distribution optimization. A demonstration of the method's utility is given by comparing sample portions evaluated using both the described methodology and standard full sample additive dose techniques. The samples used in this study are tooth enamel from teeth removed during routine dental care. We show that by making all the recommended corrections, very small masses can be both accurately measured and correlated with measurements of other samples. Some issues relating to dose distribution optimization are also addressed.

  9. Accurate EPR radiosensitivity calibration using small sample masses

    International Nuclear Information System (INIS)

    Hayes, R.B.; Haskell, E.H.; Barrus, J.K.; Kenner, G.H.; Romanyukha, A.A.

    2000-01-01

    We demonstrate a procedure in retrospective EPR dosimetry which allows for virtually nondestructive sample evaluation in terms of sample irradiations. For this procedure to work, it is shown that corrections must be made for cavity response characteristics when using variable mass samples. Likewise, methods are employed to correct for empty tube signals, sample anisotropy and frequency drift while considering the effects of dose distribution optimization. A demonstration of the method's utility is given by comparing sample portions evaluated using both the described methodology and standard full sample additive dose techniques. The samples used in this study are tooth enamel from teeth removed during routine dental care. We show that by making all the recommended corrections, very small masses can be both accurately measured and correlated with measurements of other samples. Some issues relating to dose distribution optimization are also addressed

  10. Small Mammal Sampling in Mortandad and Los Alamos Canyons, 2005

    International Nuclear Information System (INIS)

    Kathy Bennett; Sherri Sherwood; Rhonda Robinson

    2006-01-01

    As part of an ongoing ecological field investigation at Los Alamos National Laboratory, a study was conducted that compared measured contaminant concentrations in sediment to population parameters for small mammals in the Mortandad Canyon watershed. Mortandad Canyon and its tributary canyons have received contaminants from multiple solid waste management units and areas of concern since establishment of the Laboratory in the 1940s. The study included three reaches within Effluent and Mortandad canyons (E-1W, M-2W, and M-3) that had a spread in the concentrations of metals and radionuclides and included locations where polychlorinated biphenyls and perchlorate had been detected. A reference location, reach LA-BKG in upper Los Alamos Canyon, was also included in the study for comparison purposes. A small mammal study was initiated to assess whether potential adverse effects were evident in Mortandad Canyon due to the presence of contaminants, designated as contaminants of potential ecological concern, in the terrestrial media. Study sites, including the reference site, were sampled in late July/early August. Species diversity and the mean daily capture rate were the highest for E-1W reach and the lowest for the reference site. Species composition among the three reaches in Mortandad was similar with very little overlap with the reference canyon. Differences in species composition and diversity were most likely due to differences in habitat. Sex ratios, body weights, and reproductive status of small mammals were also evaluated. However, small sample sizes of some species within some sites affected the analysis. Ratios of males to females by species of each site (n = 5) were tested using a Chi-square analysis. No differences were detected. Where there was sufficient sample size, body weights of adult small mammals were compared between sites. No differences in body weights were found. Reproductive status of species appears to be similar across sites. However, sample

  11. Small Mammal Sampling in Mortandad and Los Alamos Canyons, 2005

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, Kathy; Sherwood, Sherri; Robinson, Rhonda

    2006-08-15

    As part of an ongoing ecological field investigation at Los Alamos National Laboratory, a study was conducted that compared measured contaminant concentrations in sediment to population parameters for small mammals in the Mortandad Canyon watershed. Mortandad Canyon and its tributary canyons have received contaminants from multiple solid waste management units and areas of concern since establishment of the Laboratory in the 1940s. The study included three reaches within Effluent and Mortandad canyons (E-1W, M-2W, and M-3) that had a spread in the concentrations of metals and radionuclides and included locations where polychlorinated biphenyls and perchlorate had been detected. A reference location, reach LA-BKG in upper Los Alamos Canyon, was also included in the study for comparison purposes. A small mammal study was initiated to assess whether potential adverse effects were evident in Mortandad Canyon due to the presence of contaminants, designated as contaminants of potential ecological concern, in the terrestrial media. Study sites, including the reference site, were sampled in late July/early August. Species diversity and the mean daily capture rate were the highest for E-1W reach and the lowest for the reference site. Species composition among the three reaches in Mortandad was similar with very little overlap with the reference canyon. Differences in species composition and diversity were most likely due to differences in habitat. Sex ratios, body weights, and reproductive status of small mammals were also evaluated. However, small sample sizes of some species within some sites affected the analysis. Ratios of males to females by species of each site (n = 5) were tested using a Chi-square analysis. No differences were detected. Where there was sufficient sample size, body weights of adult small mammals were compared between sites. No differences in body weights were found. Reproductive status of species appears to be similar across sites. However, sample

  12. Solution processable organic polymers and small molecules for bulk-heterojunction solar cells: A review

    International Nuclear Information System (INIS)

    Sharma, G. D.

    2011-01-01

    Solution processed bulk heterojunction (BHJ) organic solar cells (OSCs) have gained wide interest in past few years and are established as one of the leading next generation photovoltaic technologies for low cost power production. Power conversion efficiencies up to 6% and 6.5% have been reported in the literature for single layer and tandem solar cells, respectively using conjugated polymers. A recent record efficiency about 8.13% with active area of 1.13 cm 2 has been reported. However Solution processable small molecules have been widely applied for photovoltaic (PV) devices in recent years because they show strong absorption properties, and they can be easily purified and deposited onto flexible substrates at low cost. Introducing different donor and acceptor groups to construct donor--acceptor (D--A) structure small molecules has proved to be an efficient way to improve the properties of organic solar cells (OSCs). The power conversion efficiency about 4.4 % has been reported for OSCs based on the small molecules. This review deals with the recent progress of solution processable D--A structure small molecules and discusses the key factors affecting the properties of OSCs based on D--A structure small molecules: sunlight absorption, charge transport and the energy level of the molecules.

  13. Use of the small gas proportional counters for the carbon-14 measurement of very small samples

    International Nuclear Information System (INIS)

    Sayre, E.V.; Harbottle, G.; Stoenner, R.W.; Otlet, R.L.; Evans, G.V.

    1981-01-01

    Two recent developments are: the first is the mass-spectrometric separation of 14 C and 12 C ions, followed by counting of the 14 C, while the second is the extension of conventional proportional counter operation, using CO 2 as counting gas, to very small counters and samples. Although the second method is slow (months of counting time are required for 10 mg of carbon) it does not require operator intervention and many samples may be counted simultaneously. Also, it costs only a fraction of the capital expense of an accelerator installation. The development, construction and operation of suitable small counters are described, and results of three actual dating studies involving milligram scale carbon samples will be given. None of these could have been carried out if conventional, gram-sized samples had been needed. New installations, based on the use of these counters, are under construction or in the planning stages. These are located at Brookhaven Laboratory, the National Bureau of Standards (USA) and Harwell (UK). The Harwell installation, which is in advanced stages of construction, will be described in outline. The main significance of the small-counter method is, that although it will not suffice to measure the smallest (much less than 10 mg) or oldest samples, it will permit existing radiocarbon laboratories to extend their capability considerably, in the direction of smaller samples, at modest expense

  14. Local heterogeneity effects on small-sample worths

    International Nuclear Information System (INIS)

    Schaefer, R.W.

    1986-01-01

    One of the parameters usually measured in a fast reactor critical assembly is the reactivity associated with inserting a small sample of a material into the core (sample worth). Local heterogeneities introduced by the worth measurement techniques can have a significant effect on the sample worth. Unfortunately, the capability is lacking to model some of the heterogeneity effects associated with the experimental technique traditionally used at ANL (the radial tube technique). It has been suggested that these effects could account for a large portion of what remains of the longstanding central worth discrepancy. The purpose of this paper is to describe a large body of experimental data - most of which has never been reported - that shows the effect of radial tube-related local heterogeneities

  15. Method to make accurate concentration and isotopic measurements for small gas samples

    Science.gov (United States)

    Palmer, M. R.; Wahl, E.; Cunningham, K. L.

    2013-12-01

    Carbon isotopic ratio measurements of CO2 and CH4 provide valuable insight into carbon cycle processes. However, many of these studies, like soil gas, soil flux, and water head space experiments, provide very small gas sample volumes, too small for direct measurement by current constant-flow Cavity Ring-Down (CRDS) isotopic analyzers. Previously, we addressed this issue by developing a sample introduction module which enabled the isotopic ratio measurement of 40ml samples or smaller. However, the system, called the Small Sample Isotope Module (SSIM), does dilute the sample during the delivery with inert carrier gas which causes a ~5% reduction in concentration. The isotopic ratio measurements are not affected by this small dilution, but researchers are naturally interested accurate concentration measurements. We present the accuracy and precision of a new method of using this delivery module which we call 'double injection.' Two portions of the 40ml of the sample (20ml each) are introduced to the analyzer, the first injection of which flushes out the diluting gas and the second injection is measured. The accuracy of this new method is demonstrated by comparing the concentration and isotopic ratio measurements for a gas sampled directly and that same gas measured through the SSIM. The data show that the CO2 concentration measurements were the same within instrument precision. The isotopic ratio precision (1σ) of repeated measurements was 0.16 permil for CO2 and 1.15 permil for CH4 at ambient concentrations. This new method provides a significant enhancement in the information provided by small samples.

  16. Multiple solutions and stability of the steady transonic small-disturbance equation

    Directory of Open Access Journals (Sweden)

    Ya Liu

    2017-09-01

    Full Text Available Numerical solutions of the steady transonic small-disturbance (TSD potential equation are computed using the conservative Murman−Cole scheme. Multiple solutions are discovered and mapped out for the Mach number range at zero angle of attack and the angle of attack range at Mach number 0.85 for the NACA 0012 airfoil. We present a linear stability analysis method by directly assembling and evaluating the Jacobian matrix of the nonlinear finite-difference equation of the TSD equation. The stability of all the discovered multiple solutions are then determined by the proposed eigen analysis. The relation of stability to convergence of the iterative method for solving the TSD equation is discussed. Computations and the stability analysis demonstrate the possibility of eliminating the multiple solutions and stabilizing the remaining unique solution by adding a sufficiently long splitter plate downstream the airfoil trailing edge. Finally, instability of the solution of the TSD equation is shown to be closely connected to the onset of transonic buffet by comparing with experimental data.

  17. Small data global solutions for the Camassa–Choi equations

    Science.gov (United States)

    Harrop-Griffiths, Benjamin; Marzuola, Jeremy L.

    2018-05-01

    We consider solutions to the Cauchy problem for an internal-wave model derived by Camassa–Choi (1996 J. Fluid Mech. 313 83–103). This model is a natural generalization of the Benjamin–Ono and intermediate long wave equations for weak transverse effects as in the case of the Kadomtsev–Petviashvili equations for the Korteweg-de Vries equation. For that reason they are often referred to as the KP-ILW or the KP–Benjamin–Ono equations regarding finite or infinite depth respectively. We prove the existence and long-time dynamics of global solutions from small, smooth, spatially localized initial data on . The techniques applied here involve testing by wave packet techniques developed by Ifrim and Tataru in (2015 Nonlinearity 28 2661–75 2016 Bull. Soc. Math. France 144 369–94).

  18. Small angle X-ray scattering on concentrated hemoglobin solutions

    International Nuclear Information System (INIS)

    Zinke, M.; Damaschun, G.; Mueller, J.J.; Ruckpaul, K.

    1978-01-01

    The small-angle X-ray scattering technique was used to determine the intermolecular structure and interaction potentials in oxi-and deoxi-hemoglobin solutions. The pair correlation function obtained by the ZERNICKE-PRINS equation characterizes the intermolecular structure of the hemoglobin molecules. The intermolecular structure is concentration dependent. The hemoglobin molecules have a 'short range order structure' with a range of about 4 molecule diameters at 324 g/l. The potential functions of the hemoglobin-hemoglobin interaction have been determined on the basis of fluid theories. Except for the deoxi-hemoglobin solution having the concentration 370 g/l, the pair interaction consists in a short repulsion and a weak short-range attraction against kT. The potential minimum is between 1.2 - 1.5 nm above the greatest hemoglobin diameter. (author)

  19. Monitoring, Modeling, and Diagnosis of Alkali-Silica Reaction in Small Concrete Samples

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, Vivek [Idaho National Lab. (INL), Idaho Falls, ID (United States); Cai, Guowei [Idaho National Lab. (INL), Idaho Falls, ID (United States); Gribok, Andrei V. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mahadevan, Sankaran [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-01

    Assessment and management of aging concrete structures in nuclear power plants require a more systematic approach than simple reliance on existing code margins of safety. Structural health monitoring of concrete structures aims to understand the current health condition of a structure based on heterogeneous measurements to produce high-confidence actionable information regarding structural integrity that supports operational and maintenance decisions. This report describes alkali-silica reaction (ASR) degradation mechanisms and factors influencing the ASR. A fully coupled thermo-hydro-mechanical-chemical model developed by Saouma and Perotti by taking into consideration the effects of stress on the reaction kinetics and anisotropic volumetric expansion is presented in this report. This model is implemented in the GRIZZLY code based on the Multiphysics Object Oriented Simulation Environment. The implemented model in the GRIZZLY code is randomly used to initiate ASR in a 2D and 3D lattice to study the percolation aspects of concrete. The percolation aspects help determine the transport properties of the material and therefore the durability and service life of concrete. This report summarizes the effort to develop small-size concrete samples with embedded glass to mimic ASR. The concrete samples were treated in water and sodium hydroxide solution at elevated temperature to study how ingress of sodium ions and hydroxide ions at elevated temperature impacts concrete samples embedded with glass. Thermal camera was used to monitor the changes in the concrete sample and results are summarized.

  20. Multi-solution processes of small molecule for flexible white organic light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Yu-Sheng, E-mail: ystsai@nfu.edu.tw [Institute of Electro-optical and Materials Science, National Formosa University, Yunlin 63201, Taiwan, ROC (China); Chittawanij, Apisit; Hong, Lin-Ann; Guo, Siou-Wei [Institute of Electro-optical and Materials Science, National Formosa University, Yunlin 63201, Taiwan, ROC (China); Wang, Ching-Chiun [Department of Solid State Lighting Technology, Mechanical and Systems Research Laboratories, Industrial Technology Research Institute, Hsinchu 31040, Taiwan, ROC (China); Juang, Fuh-Shyang [Institute of Electro-optical and Materials Science, National Formosa University, Yunlin 63201, Taiwan, ROC (China); Lai, Shih-Hsiang [Department of Solid State Lighting Technology, Mechanical and Systems Research Laboratories, Industrial Technology Research Institute, Hsinchu 31040, Taiwan, ROC (China); Lin, Yang-Ching [Institute of Electro-optical and Materials Science, National Formosa University, Yunlin 63201, Taiwan, ROC (China)

    2016-04-01

    Most small molecule organic light emitting diode (SM-OLED) device structures are made in one layer using solution-based processing because the solution is usually a high dissolvent material that easily attacks the layer below it. We demonstrate a simple and reliable stamping technique for fabricating multi-solution process flexible white SM-OLEDs. The structure is anode/spin-hole injection layer/spin-emitting layer/stamping-electron transport layer/cathode. Poly(di-methyl silane) (PDMS) stamp is used for transferring electron transport layer. An intermediate ultraviolet-ozone surface treatment is introduced to temporarily modify the PDMS stamp surface. Then, the solution-based electron transport layer film can therefore be uniformly formed on top of the PDMS surface. After that the electron transport layer film on the PDMS stamp is transfer-printed onto the emitting layer with suitable heating and pressing. A solution-based processing is successfully established to efficiently fabricate flexible white SM-OLEDs. The SM-OLEDs were obtained at the current density of 20 mA/cm{sup 2}, luminance of 1062 cd/m{sup 2}, current efficiency of 5.57 cd/A, and Commission internationale de l'éclairage coordinate of (0.32, 0.35). - Highlights: • All solution-processed small molecule materials (emitting layer, electron transport layer). • Poly(di-methylsilane) (PDMS) stamp is subsequently used for stamping transfer. • The flexible white SM-OLEDs are based on solution-processes with a low-cost method.

  1. Multi-solution processes of small molecule for flexible white organic light-emitting diodes

    International Nuclear Information System (INIS)

    Tsai, Yu-Sheng; Chittawanij, Apisit; Hong, Lin-Ann; Guo, Siou-Wei; Wang, Ching-Chiun; Juang, Fuh-Shyang; Lai, Shih-Hsiang; Lin, Yang-Ching

    2016-01-01

    Most small molecule organic light emitting diode (SM-OLED) device structures are made in one layer using solution-based processing because the solution is usually a high dissolvent material that easily attacks the layer below it. We demonstrate a simple and reliable stamping technique for fabricating multi-solution process flexible white SM-OLEDs. The structure is anode/spin-hole injection layer/spin-emitting layer/stamping-electron transport layer/cathode. Poly(di-methyl silane) (PDMS) stamp is used for transferring electron transport layer. An intermediate ultraviolet-ozone surface treatment is introduced to temporarily modify the PDMS stamp surface. Then, the solution-based electron transport layer film can therefore be uniformly formed on top of the PDMS surface. After that the electron transport layer film on the PDMS stamp is transfer-printed onto the emitting layer with suitable heating and pressing. A solution-based processing is successfully established to efficiently fabricate flexible white SM-OLEDs. The SM-OLEDs were obtained at the current density of 20 mA/cm"2, luminance of 1062 cd/m"2, current efficiency of 5.57 cd/A, and Commission internationale de l'éclairage coordinate of (0.32, 0.35). - Highlights: • All solution-processed small molecule materials (emitting layer, electron transport layer). • Poly(di-methylsilane) (PDMS) stamp is subsequently used for stamping transfer. • The flexible white SM-OLEDs are based on solution-processes with a low-cost method.

  2. Weighted piecewise LDA for solving the small sample size problem in face verification.

    Science.gov (United States)

    Kyperountas, Marios; Tefas, Anastasios; Pitas, Ioannis

    2007-03-01

    A novel algorithm that can be used to boost the performance of face-verification methods that utilize Fisher's criterion is presented and evaluated. The algorithm is applied to similarity, or matching error, data and provides a general solution for overcoming the "small sample size" (SSS) problem, where the lack of sufficient training samples causes improper estimation of a linear separation hyperplane between the classes. Two independent phases constitute the proposed method. Initially, a set of weighted piecewise discriminant hyperplanes are used in order to provide a more accurate discriminant decision than the one produced by the traditional linear discriminant analysis (LDA) methodology. The expected classification ability of this method is investigated throughout a series of simulations. The second phase defines proper combinations for person-specific similarity scores and describes an outlier removal process that further enhances the classification ability. The proposed technique has been tested on the M2VTS and XM2VTS frontal face databases. Experimental results indicate that the proposed framework greatly improves the face-verification performance.

  3. Evaluation of a pyridoxylated hemoglobin polyoxyethylene conjugate solution as a perfusate for small intestine preservation.

    Science.gov (United States)

    Liu, H; Agishi, T; Kawai, T; Hayashi, T; Fujita, S; Fuchinoue, S; Takahashi, K; Teraoka, S; Ota, K

    1992-01-01

    A new type of artificial blood, pyridoxylated hemoglobin-polyoxyethylene conjugate (PHP) solution, (developed by PHP research group of the department of health and welfare of Japan, and produced by Ajinomoto Co., Inc. Tokyo) as an oxygen-carrying component, has been recently devised using hemoglobin obtained from hemolyzed human erythrocytes. Recently, the studies using this solution as a preservation solution were performed in some instances. To examine the mechanism of improved viability using this solution as a preservation solution, we developed a model of orthotopic small intestine transplantation (OIT) in the rat. As a baseline study, we compared parameters of viability of the grafts preserved in Collins and UW solution to those preserved in PHP solution including a survival rate, a serum level total protein and albumin, and a change in body weight after transplantation. In our study, the simple hypothermia storage together with intestinal perfusion preservation with PHP solution was performed. Animals were divided into 6, 12, and 24 hr preservation groups. All of the rats survived after 6 hr preservation following transplantation. However, in 12 hr storage, five of six rats in PHP solution preservation survived and recovery in body weight after grafting was better than those with Collins and UW solution. We conclude that the PHP solution is, therefore, considered to possibly be a more suitable perfusate for small intestine preservation than Collins and UW solution.

  4. 77 FR 11618 - Solutions Capital I, L.P.; Notice Seeking Exemption Under the Small Business Investment Act...

    Science.gov (United States)

    2012-02-27

    ... SMALL BUSINESS ADMINISTRATION [License No. 03/03-0247] Solutions Capital I, L.P.; Notice Seeking Exemption Under the Small Business Investment Act, Conflicts of Interest Notice is hereby given that Solutions Capital I, L.P., 1100 Wilson Blvd., Suite 3000, Arlington, VA 22209, a Federal Licensee under the...

  5. Radioenzymatic assay for trimethoprim in very small serum samples.

    OpenAIRE

    Yogev, R; Melick, C; Tan-Pong, L

    1985-01-01

    A modification of the methotrexate radioassay kit (supplied by New England Enzyme Center) enabled determination of trimethoprim levels in 5-microliter serum samples. An excellent correlation between this assay and high-pressure liquid chromatography assay was found. These preliminary results suggest that with this method rapid determination of trimethoprim levels in very small samples (5 to 10 microliters) can be achieved.

  6. Radioenzymatic assay for trimethoprim in very small serum samples

    International Nuclear Information System (INIS)

    Yogev, R.; Melick, C.; Tan-Pong, L.

    1985-01-01

    A modification of the methotrexate radioassay kit (supplied by New England Enzyme Center) enabled determination of trimethoprim levels in 5-microliter serum samples. An excellent correlation between this assay and high-pressure liquid chromatography assay was found. These preliminary results suggest that with this method rapid determination of trimethoprim levels in very small samples (5 to 10 microliters) can be achieved

  7. High-resolution neutron spectroscopy on protein solution samples

    International Nuclear Information System (INIS)

    Grimaldo, M.; Henning, M.; Roosen-Runge, F.; Seydel, T.; Jalarvo, N.; Zamponi, M.; Zanini, F.; Zhang, F.; Schreiber, F.

    2015-01-01

    Proteins in solution are subject to a complex superposition of global translational and rotational diffusion as well as internal relaxations covering a wide range of time scales. With the advent of new high-flux neutron spectrometers in combination with enhanced analysis frameworks it has become possible to separate these different contributions. We discuss new approaches to the analysis by presenting example spectra and fits from data recorded on the backscattering spectrometers IN16, IN16B, and BASIS on the same protein solution sample. We illustrate the separation of the rotational and translational diffusion contribution, the accurate treatment of the solvent contribution, and the extraction of information on internal fluctuations. We also highlight the progress made in passing from second- to third-generation backscattering spectrometers. (authors)

  8. Estimating sample size for a small-quadrat method of botanical ...

    African Journals Online (AJOL)

    Reports the results of a study conducted to determine an appropriate sample size for a small-quadrat method of botanical survey for application in the Mixed Bushveld of South Africa. Species density and grass density were measured using a small-quadrat method in eight plant communities in the Nylsvley Nature Reserve.

  9. Predictive Sampling of Rare Conformational Events in Aqueous Solution: Designing a Generalized Orthogonal Space Tempering Method.

    Science.gov (United States)

    Lu, Chao; Li, Xubin; Wu, Dongsheng; Zheng, Lianqing; Yang, Wei

    2016-01-12

    In aqueous solution, solute conformational transitions are governed by intimate interplays of the fluctuations of solute-solute, solute-water, and water-water interactions. To promote molecular fluctuations to enhance sampling of essential conformational changes, a common strategy is to construct an expanded Hamiltonian through a series of Hamiltonian perturbations and thereby broaden the distribution of certain interactions of focus. Due to a lack of active sampling of configuration response to Hamiltonian transitions, it is challenging for common expanded Hamiltonian methods to robustly explore solvent mediated rare conformational events. The orthogonal space sampling (OSS) scheme, as exemplified by the orthogonal space random walk and orthogonal space tempering methods, provides a general framework for synchronous acceleration of slow configuration responses. To more effectively sample conformational transitions in aqueous solution, in this work, we devised a generalized orthogonal space tempering (gOST) algorithm. Specifically, in the Hamiltonian perturbation part, a solvent-accessible-surface-area-dependent term is introduced to implicitly perturb near-solute water-water fluctuations; more importantly in the orthogonal space response part, the generalized force order parameter is generalized as a two-dimension order parameter set, in which essential solute-solvent and solute-solute components are separately treated. The gOST algorithm is evaluated through a molecular dynamics simulation study on the explicitly solvated deca-alanine (Ala10) peptide. On the basis of a fully automated sampling protocol, the gOST simulation enabled repetitive folding and unfolding of the solvated peptide within a single continuous trajectory and allowed for detailed constructions of Ala10 folding/unfolding free energy surfaces. The gOST result reveals that solvent cooperative fluctuations play a pivotal role in Ala10 folding/unfolding transitions. In addition, our assessment

  10. Overestimation of test performance by ROC analysis: Effect of small sample size

    International Nuclear Information System (INIS)

    Seeley, G.W.; Borgstrom, M.C.; Patton, D.D.; Myers, K.J.; Barrett, H.H.

    1984-01-01

    New imaging systems are often observer-rated by ROC techniques. For practical reasons the number of different images, or sample size (SS), is kept small. Any systematic bias due to small SS would bias system evaluation. The authors set about to determine whether the area under the ROC curve (AUC) would be systematically biased by small SS. Monte Carlo techniques were used to simulate observer performance in distinguishing signal (SN) from noise (N) on a 6-point scale; P(SN) = P(N) = .5. Four sample sizes (15, 25, 50 and 100 each of SN and N), three ROC slopes (0.8, 1.0 and 1.25), and three intercepts (0.8, 1.0 and 1.25) were considered. In each of the 36 combinations of SS, slope and intercept, 2000 runs were simulated. Results showed a systematic bias: the observed AUC exceeded the expected AUC in every one of the 36 combinations for all sample sizes, with the smallest sample sizes having the largest bias. This suggests that evaluations of imaging systems using ROC curves based on small sample size systematically overestimate system performance. The effect is consistent but subtle (maximum 10% of AUC standard deviation), and is probably masked by the s.d. in most practical settings. Although there is a statistically significant effect (F = 33.34, P<0.0001) due to sample size, none was found for either the ROC curve slope or intercept. Overestimation of test performance by small SS seems to be an inherent characteristic of the ROC technique that has not previously been described

  11. Statistical issues in reporting quality data: small samples and casemix variation.

    Science.gov (United States)

    Zaslavsky, A M

    2001-12-01

    To present two key statistical issues that arise in analysis and reporting of quality data. Casemix variation is relevant to quality reporting when the units being measured have differing distributions of patient characteristics that also affect the quality outcome. When this is the case, adjustment using stratification or regression may be appropriate. Such adjustments may be controversial when the patient characteristic does not have an obvious relationship to the outcome. Stratified reporting poses problems for sample size and reporting format, but may be useful when casemix effects vary across units. Although there are no absolute standards of reliability, high reliabilities (interunit F > or = 10 or reliability > or = 0.9) are desirable for distinguishing above- and below-average units. When small or unequal sample sizes complicate reporting, precision may be improved using indirect estimation techniques that incorporate auxiliary information, and 'shrinkage' estimation can help to summarize the strength of evidence about units with small samples. With broader understanding of casemix adjustment and methods for analyzing small samples, quality data can be analysed and reported more accurately.

  12. SCM Paste Samples Exposed To Aggressive Solutions. Cementitious Barriers Partnership

    International Nuclear Information System (INIS)

    Foster, T.

    2014-01-01

    This report summarizes experimental work performed by SIMCO Technologies Inc. (SIMCO) as part of the Cementitious Barriers Partnership (CBP) project. The test series followed an experimental program dedicated to the study of ordinary Portland cement (OPC) hydrated cement pastes exposed to aggressive solutions. In the present study, the scope is extended to hydrated cement pastes incorporating supplementary cementitious materials (SCM) such as fly ash and ground granulated blast furnace slag (GGBFS). Also, the range of aggressive contact solutions was expanded. The experimental program aimed at testing aggressive contact solutions that more closely mimic the chemical composition of saltstone pore solution. Five different solutions, some of which incorporated high levels of carbonate and nitrate, were placed in contact with four different hydrated cement paste mixes. In all solutions, 150 mmol/L of SO 4 2- (14 400 ppm) were present. The solutions included different pH conditions and different sodium content. Two paste mixes were equivalent to Vault 1/4 and Vault 2 concrete mixes used at SRS in storage structures. Two additional paste mixes, cast at the same water-to-cement ratio and using the same cements but without SCMs, were also tested. The damage evolution in samples was monitored using ultrasonic pulse velocity (UPV) and mass measurements. After three and twelve months of exposure conditions, samples were taken out of solution containers and analyzed to perform migration tests and porosity measurements. Globally, results were in line with the previous study and confirmed that high pH may limit the formation of some deleterious phases like gypsum. In this case, ettringite may form but is not necessarily associated with damage. However, the high concentration of sodium may be associated with the formation of an AFm-like mineral called U-phase. The most significant evidences of damage were all associated with the Vault 2 paste analog. This material

  13. SCM Paste Samples Exposed To Aggressive Solutions. Cementitious Barriers Partnership

    Energy Technology Data Exchange (ETDEWEB)

    Foster, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2014-12-01

    This report summarizes experimental work performed by SIMCO Technologies Inc. (SIMCO) as part of the Cementitious Barriers Partnership (CBP) project. The test series followed an experimental program dedicated to the study of ordinary Portland cement (OPC) hydrated cement pastes exposed to aggressive solutions. In the present study, the scope is extended to hydrated cement pastes incorporating supplementary cementitious materials (SCM) such as fly ash and ground granulated blast furnace slag (GGBFS). Also, the range of aggressive contact solutions was expanded. The experimental program aimed at testing aggressive contact solutions that more closely mimic the chemical composition of saltstone pore solution. Five different solutions, some of which incorporated high levels of carbonate and nitrate, were placed in contact with four different hydrated cement paste mixes. In all solutions, 150 mmol/L of SO42– (14 400 ppm) were present. The solutions included different pH conditions and different sodium content. Two paste mixes were equivalent to Vault 1/4 and Vault 2 concrete mixes used at SRS in storage structures. Two additional paste mixes, cast at the same water-to-cement ratio and using the same cements but without SCMs, were also tested. The damage evolution in samples was monitored using ultrasonic pulse velocity (UPV) and mass measurements. After three and twelve months of exposure conditions, samples were taken out of solution containers and analyzed to perform migration tests and porosity measurements. Globally, results were in line with the previous study and confirmed that high pH may limit the formation of some deleterious phases like gypsum. In this case, ettringite may form but is not necessarily associated with damage. However, the high concentration of sodium may be associated with the formation of an AFm-like mineral called U-phase. The most significant evidences of damage were all associated with the Vault 2 paste analog. This

  14. Optimizing the triple-axis spectrometer PANDA at the MLZ for small samples and complex sample environment conditions

    Science.gov (United States)

    Utschick, C.; Skoulatos, M.; Schneidewind, A.; Böni, P.

    2016-11-01

    The cold-neutron triple-axis spectrometer PANDA at the neutron source FRM II has been serving an international user community studying condensed matter physics problems. We report on a new setup, improving the signal-to-noise ratio for small samples and pressure cell setups. Analytical and numerical Monte Carlo methods are used for the optimization of elliptic and parabolic focusing guides. They are placed between the monochromator and sample positions, and the flux at the sample is compared to the one achieved by standard monochromator focusing techniques. A 25 times smaller spot size is achieved, associated with a factor of 2 increased intensity, within the same divergence limits, ± 2 ° . This optional neutron focusing guide shall establish a top-class spectrometer for studying novel exotic properties of matter in combination with more stringent sample environment conditions such as extreme pressures associated with small sample sizes.

  15. Toward new instruments for measurement of low concentration hydrogen sulfide in small-quantity aqueous solutions

    International Nuclear Information System (INIS)

    Wu, Xiao Chu; Wu, Dong Qing; Zhang, W J; Sammynaiken, R; Yang, Wei; Wang, Rui

    2008-01-01

    Endogenously generated hydrogen sulfide (H 2 S) has been found to play some important physiological roles in the nervous and cardiovascular systems, such as a neuromodulator and a vasorelaxant. These roles are in contrast to our common perception that H 2 S is toxic. However, whether H 2 S plays a positive or negative role is dependent on the H 2 S concentration levels in mammals. This further puts a high demand on the accurate measurement of H 2 S in mammals with a further desire to be real time, continuous and in vivo. Existing methods for H 2 S measurement require a large number of tissue samples with complex procedures, and these methods are extremely invasive. The development of new in vivo and real-time methods for measuring H 2 S is, however, a great challenge. In the present study, we proposed and examined five potential H 2 S measurement methods: (1) atomic force microscopy with coating materials, (2) Raman spectroscopy on the H 2 S solutions, (3) gas chromatography/mass spectroscopy (with the static headspace technique) on the H 2 S solutions, (4) mass spectroscopy on unfunctionalized carbon nanotubes treated with the H 2 S solutions and (5) Raman spectroscopy on unfunctionalized carbon nanotubes treated with the H 2 S solutions. Our study concluded that method (5) is the most promising one for detecting low concentration H 2 S in small-quantity aqueous solutions in terms of measurement resolution and non-invasiveness, but the method is not very robust

  16. System for sampling active solutions in transport container; Systeme de prelevements de solutions actives sur les recipients de transport

    Energy Technology Data Exchange (ETDEWEB)

    Fradin, J.

    1958-12-03

    This report presents a system aimed at sampling active solution from a specific transport container (SCRGR model) while transferring this solution with a maximum safety. The sampling principle is described (a flexible tube connected to the receiving container, with a needle at the other end which goes through a rubber membrane and enters a plunger tube). Its benefits are outlined (operator protection, reduction of contamination risk; only the rubber membrane is removed and replaced). Some manufacturing details are described concerning the membrane and the cover.

  17. Systems and methods for laser assisted sample transfer to solution for chemical analysis

    Science.gov (United States)

    Van Berkel, Gary J; Kertesz, Vilmos; Ovchinnikova, Olga S

    2013-08-27

    Systems and methods are described for laser ablation of an analyte from a specimen and capturing of the analyte in a dispensed solvent to form a testing solution. A solvent dispensing and extraction system can form a liquid microjunction with the specimen. The solvent dispensing and extraction system can include a surface sampling probe. The laser beam can be directed through the surface sampling probe. The surface sampling probe can also serve as an atomic force microscopy probe. The surface sampling probe can form a seal with the specimen. The testing solution including the analyte can then be analyzed using an analytical instrument or undergo further processing.

  18. Analysis of the Sodium Recirculation Theory of Solute Coupled Water Transport in Small Intestine

    DEFF Research Database (Denmark)

    Larsen, E. H.; Sørensen, Jens Nørkær; Sørensen, J. B.

    2002-01-01

    Our previous mathematical model of solute-coupled water transport through the intestinal epithelium is extended for dealing with electrolytes rather than electroneutral solutes. A 3Na+-2K+ pump in the lateral membranes provides the energy-requiring step for driving transjunctional and translateral......, computations predict that the concentration differences between lis and bathing solutions are small for all three ions. Nevertheless, the diffusion fluxes of the ions out of lis significantly exceed their mass transports. It is concluded that isotonic transport requires recirculation of all three ions....... The computed sodium recirculation flux that is required for isotonic transport corresponds to that estimated in experiments on toad small intestine. This result is shown to be robust and independent of whether the apical entrance mechanism for the sodium ion is a channel, a SGLT1 transporter driving inward...

  19. Preparing Monodisperse Macromolecular Samples for Successful Biological Small-Angle X-ray and Neutron Scattering Experiments

    Science.gov (United States)

    Jeffries, Cy M.; Graewert, Melissa A.; Blanchet, Clément E.; Langley, David B.; Whitten, Andrew E.; Svergun, Dmitri I

    2017-01-01

    Small-angle X-ray and neutron scattering (SAXS and SANS) are techniques used to extract structural parameters and determine the overall structures and shapes of biological macromolecules, complexes and assemblies in solution. The scattering intensities measured from a sample contain contributions from all atoms within the illuminated sample volume including the solvent and buffer components as well as the macromolecules of interest. In order to obtain structural information, it is essential to prepare an exactly matched solvent blank so that background scattering contributions can be accurately subtracted from the sample scattering to obtain the net scattering from the macromolecules in the sample. In addition, sample heterogeneity caused by contaminants, aggregates, mismatched solvents, radiation damage or other factors can severely influence and complicate data analysis so it is essential that the samples are pure and monodisperse for the duration of the experiment. This Protocol outlines the basic physics of SAXS and SANS and reveals how the underlying conceptual principles of the techniques ultimately ‘translate’ into practical laboratory guidance for the production of samples of sufficiently high quality for scattering experiments. The procedure describes how to prepare and characterize protein and nucleic acid samples for both SAXS and SANS using gel electrophoresis, size exclusion chromatography and light scattering. Also included are procedures specific to X-rays (in-line size exclusion chromatography SAXS) and neutrons, specifically preparing samples for contrast matching/variation experiments and deuterium labeling of proteins. PMID:27711050

  20. Conversion of Small Algal Oil Sample to JP-8

    Science.gov (United States)

    2012-01-01

    cracking of Algal Oil to SPK Hydroprocessing Lab Plant uop Nitrogen Hydrogen Product ., __ Small Scale Lab Hydprocessing plant - Down flow trickle ... bed configuration - Capable of retaining 25 cc of catalyst bed Meter UOP ·CONFIDENTIAL File Number The catalytic deoxygenation stage of the...content which combined with the samples acidity, is a challenge to reactor metallurgy. None the less, an attempt was made to convert this sample to

  1. Small molecule solution-processed bulk heterojunction solar cells with inverted structure using porphyrin donor

    Science.gov (United States)

    Yamamoto, Takaki; Hatano, Junichi; Nakagawa, Takafumi; Yamaguchi, Shigeru; Matsuo, Yutaka

    2013-01-01

    Utilizing tetraethynyl porphyrin derivative (TE-Por) as a small molecule donor material, we fabricated a small molecule solution-processed bulk heterojunction (BHJ) solar cell with inverted structure, which exhibited 1.6% power conversion efficiency (JSC (short-circuit current) = 4.6 mA/cm2, VOC (open-circuit voltage) = 0.90 V, and FF (fill factor) = 0.39) in the device configuration indium tin oxide/TiOx (titanium sub-oxide)/[6,6]-phenyl-C61-butyric acid methyl ester:TE-Por (5:1)/MoOx (molybdenum sub-oxide)/Au under AM1.5 G illumination at 100 mW/cm2. Without encapsulation, the small molecule solution-processed inverted BHJ solar cell also showed remarkable durability to air, where it kept over 73% of its initial power conversion efficiency after storage for 28 days under ambient atmosphere in the dark.

  2. Periodic Solutions of a System of Delay Differential Equations for a Small Delay

    Directory of Open Access Journals (Sweden)

    Adu A.M. Wasike

    2002-06-01

    Full Text Available We prove the existence of an asymptotically stable periodic solution of a system of delay differential equations with a small time delay t > 0. To achieve this, we transform the system of equations into a system of perturbed ordinary differential equations and then use perturbation results to show the existence of an asymptotically stable periodic solution. This approach is contingent on the fact that the system of equations with t = 0 has a stable limit cycle. We also provide a comparative study of the solutions of the original system and the perturbed system.  This comparison lays the ground for proving the existence of periodic solutions of the original system by Schauder's fixed point theorem.

  3. Some Factors Hindering Acceptance of Three Gamification Solutions in Motivation Systems, in Small and Medium Enterprises

    Directory of Open Access Journals (Sweden)

    Jacek WOŹNIAK

    2017-12-01

    Full Text Available Gamification, understood as a use of chosen game mechanisms for motivating actors in non-game contexts, is increasingly popular and has become one of the “hot topics” of managerial practice and science. Despite its widespread use in HRM, several barriers preventing its progress in certain types of organizations have been identified. Small and medium enterprises (SMEs, where employees are not accustomed to formal procedures are a specific example, as gamification is based on formal procedures. The goal of the text is to analyze employees’ opinions concerning the incorporation of chosen gaming mechanisms into their motivation systems, to check if not being accustomed to formal procedures is a barrier. Beside “typical” SMEs where the entrepreneur is present, direct relations within a team are also characteristic of company departments which achieve their goals almost without contact with the rest of the organization – as in the case of a discount stores chain. The study bases on two samples to check if being accustomed to formal procedures in the small team facilitates acceptance of gamification. Two questionnaires (one on a sample of 100 employees of a discount store chain, and the second on 73 “typical” SME employees asked respondents to declare their preferences for different types of rewards in motivation systems, including readiness to be involved in two gamification-type solutions: based on (i lotteries, or (ii BLAP gaming with non-material and material prizes. The effects of chosen factors: psychological (risk aversion and situational (dissatisfaction with current incentive system on the perception of two different ways of incorporating gamification into motivational systems, were analyzed. The results show that dissatisfaction with the current incentive system and not being risk-averse favor accepting the incorporation of gamification solutions into motivational systems. The responses of discount store employees and SME

  4. A scanning tunneling microscope capable of imaging specified micron-scale small samples

    Science.gov (United States)

    Tao, Wei; Cao, Yufei; Wang, Huafeng; Wang, Kaiyou; Lu, Qingyou

    2012-12-01

    We present a home-built scanning tunneling microscope (STM) which allows us to precisely position the tip on any specified small sample or sample feature of micron scale. The core structure is a stand-alone soft junction mechanical loop (SJML), in which a small piezoelectric tube scanner is mounted on a sliding piece and a "U"-like soft spring strip has its one end fixed to the sliding piece and its opposite end holding the tip pointing to the sample on the scanner. Here, the tip can be precisely aligned to a specified small sample of micron scale by adjusting the position of the spring-clamped sample on the scanner in the field of view of an optical microscope. The aligned SJML can be transferred to a piezoelectric inertial motor for coarse approach, during which the U-spring is pushed towards the sample, causing the tip to approach the pre-aligned small sample. We have successfully approached a hand cut tip that was made from 0.1 mm thin Pt/Ir wire to an isolated individual 32.5 × 32.5 μm2 graphite flake. Good atomic resolution images and high quality tunneling current spectra for that specified tiny flake are obtained in ambient conditions with high repeatability within one month showing high and long term stability of the new STM structure. In addition, frequency spectra of the tunneling current signals do not show outstanding tip mount related resonant frequency (low frequency), which further confirms the stability of the STM structure.

  5. A scanning tunneling microscope capable of imaging specified micron-scale small samples.

    Science.gov (United States)

    Tao, Wei; Cao, Yufei; Wang, Huafeng; Wang, Kaiyou; Lu, Qingyou

    2012-12-01

    We present a home-built scanning tunneling microscope (STM) which allows us to precisely position the tip on any specified small sample or sample feature of micron scale. The core structure is a stand-alone soft junction mechanical loop (SJML), in which a small piezoelectric tube scanner is mounted on a sliding piece and a "U"-like soft spring strip has its one end fixed to the sliding piece and its opposite end holding the tip pointing to the sample on the scanner. Here, the tip can be precisely aligned to a specified small sample of micron scale by adjusting the position of the spring-clamped sample on the scanner in the field of view of an optical microscope. The aligned SJML can be transferred to a piezoelectric inertial motor for coarse approach, during which the U-spring is pushed towards the sample, causing the tip to approach the pre-aligned small sample. We have successfully approached a hand cut tip that was made from 0.1 mm thin Pt∕Ir wire to an isolated individual 32.5 × 32.5 μm(2) graphite flake. Good atomic resolution images and high quality tunneling current spectra for that specified tiny flake are obtained in ambient conditions with high repeatability within one month showing high and long term stability of the new STM structure. In addition, frequency spectra of the tunneling current signals do not show outstanding tip mount related resonant frequency (low frequency), which further confirms the stability of the STM structure.

  6. Small angle x-ray scattering from proteins in solution

    International Nuclear Information System (INIS)

    de Souza, C.F.; Torriani, I.L.; Bonafe, C.F.S.; Merrelles, N.C.; Vachette, P.

    1989-01-01

    In this work the authors report experiments performed with giant respiratory proteins from annelids (erythrocruorins), known to have a molecular weight in the order of four million Daltons. Preliminary x-ray scattering data was obtained using a conventional rotating anode source. High resolution small angle scattering curves were obtained with synchrotron radiation from the DCI storage ring at LURE. Data from solutions with several protein concentrations were analyzed in order to determine low resolution dimensional parameters, using Guinier plots from the smeared scattering curves and the inverse transformation method

  7. Low cost infrastructure solutions for small embedded wind generators

    Energy Technology Data Exchange (ETDEWEB)

    Robb, C.

    2003-07-01

    This report gives details of a project to demonstrate novel economic solutions to increase the potential for installing small-scale embedded wind generator systems at many UK sites which have so far been dismissed as too difficult. Details are given of the first phase of the study which examined current solutions to infrastructure problems and potential techniques. The use of drilled rock anchor foundations to minimise the need for delivery of ready-mix concrete to wind turbine sites, and the use of a winch and A-frame system for erecting a wind turbine to avoid the use of cranes are discussed. The demonstration of the installation of a 50kW wind turbine on the Isle of Luing in Scotland where there is no access for cranes or larger vehicles in the second phase of the project is described. The potential for the use of these techniques on larger wind turbines is considered.

  8. Existence of Generalized Homoclinic Solutions of Lotka-Volterra System under a Small Perturbation

    OpenAIRE

    Mi, Yuzhen

    2016-01-01

    This paper investigates Lotka-Volterra system under a small perturbation vxx=-μ(1-a2u-v)v+ϵf(ϵ,v,vx,u,ux), uxx=-(1-u-a1v)u+ϵg(ϵ,v,vx,u,ux). By the Fourier series expansion technique method, the fixed point theorem, the perturbation theorem, and the reversibility, we prove that near μ=0 the system has a generalized homoclinic solution exponentially approaching a periodic solution.

  9. Existence of Generalized Homoclinic Solutions of Lotka-Volterra System under a Small Perturbation

    Directory of Open Access Journals (Sweden)

    Yuzhen Mi

    2016-01-01

    Full Text Available This paper investigates Lotka-Volterra system under a small perturbation vxx=-μ(1-a2u-vv+ϵf(ϵ,v,vx,u,ux, uxx=-(1-u-a1vu+ϵg(ϵ,v,vx,u,ux. By the Fourier series expansion technique method, the fixed point theorem, the perturbation theorem, and the reversibility, we prove that near μ=0 the system has a generalized homoclinic solution exponentially approaching a periodic solution.

  10. Thermal neutron absorption cross-section for small samples (experiments in cylindrical geometry)

    International Nuclear Information System (INIS)

    Czubek, J.A.; Drozdowicz, K.; Igielski, A.; Krynicka-Drozdowicz, E.; Woznicka, U.

    1982-01-01

    Measurement results for thermal neutron macroscopic absorption cross-sections Σsub(a)1 when applying the cylindrical sample-moderator system are presented. Experiments for liquid (water solutions of H 3 BO 3 ) and solid (crushed basalts) samples are reported. Solid samples have been saturated with the H 3 BO 3 ''poisoning'' solution. The accuracy obtained for the determination of the absorption cross-section of the solid material was σ(Σsub(ma))=(1.2+2.2) c.u. in the case when porosity was measured with the accuracy of σ(phi)=0.001+0.002. The dispersion of the Σsub(ma) data obtained for basalts (taken from different quarries) was higher than the accuracy of the measurement. All experimental data for the fundamental decay constants lambda 0 together with the whole information about the samples are given. (author)

  11. Small-angle neutron scattering study of D2O-alcohol solutions

    International Nuclear Information System (INIS)

    D'Arrigo, G.

    1990-01-01

    Small-angle neutron scattering (SANS) measurements have been carried out on heavy water solutions of ethanol, isopropyl alcohol, n-propyl alcohol, t-butyl alcohol and butoxyethanol between 5 and 37 0 C at the concentrations where ultrasonic attenuation exhibits peak values. The wavevector dependence and the absolute intensity of the scattered intensities were analysed according to a microscopic model of the solutions in terms of aggregated complexes. The results indicate that at 25 0 C there exist either alcohol 'micelle-like' structures or alcohol-heavy water complexes which increase on going from the lower to higher alcohol solutions. As temperature increases from 25 to 37 0 C a higher aggregation is observed in butyl alcohol and butoxyethanol solutions. This behaviour is attributed to the demixing tendency of these systems at high temperatures. On going from 25 to 5 0 C the aggregation increases again. This trend is associated with the anomalous behaviour of the specific heat and ultrasonic attenuation of these systems. The occurrence of a low-temperature phase transition suggested by these anomalies is supported by our results. (author)

  12. Fluorimetrich determination of uranium in mineral samples and phosphoric solutions

    International Nuclear Information System (INIS)

    Pupo Gonzales, I.; Cuevillas, J.; Estevez, J.

    1991-01-01

    In this paper an analytical technique for the determination of uranium in different cuban minerals and acid leaching liquors of phosphorites is proposed. The method used for solid samples includes their disolution and further dilution of the solution obtained. For liquid samples dilution is the only intermediate step used. A study of HNO3 concentration (pH) was made in fluorimetric measurements. The method was applied to the uranium analysis in two IAEA standard reference samples (phosphate base), in natural phosphorites and a synthetic one, in clays and phosphoric liquors. The results agree with those obtained by other methods

  13. Shock formation in small-data solutions to 3D quasilinear wave equations

    CERN Document Server

    Speck, Jared

    2016-01-01

    In 1848 James Challis showed that smooth solutions to the compressible Euler equations can become multivalued, thus signifying the onset of a shock singularity. Today it is known that, for many hyperbolic systems, such singularities often develop. However, most shock-formation results have been proved only in one spatial dimension. Serge Alinhac's groundbreaking work on wave equations in the late 1990s was the first to treat more than one spatial dimension. In 2007, for the compressible Euler equations in vorticity-free regions, Demetrios Christodoulou remarkably sharpened Alinhac's results and gave a complete description of shock formation. In this monograph, Christodoulou's framework is extended to two classes of wave equations in three spatial dimensions. It is shown that if the nonlinear terms fail to satisfy the null condition, then for small data, shocks are the only possible singularities that can develop. Moreover, the author exhibits an open set of small data whose solutions form a shock, and he prov...

  14. Solute-solute interactions in intermetallic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Debashis; Murray, Ryan; Collins, Gary S., E-mail: collins@wsu.edu [Washington State University, Department of Physics and Astronomy (United States); Zacate, Matthew O. [Northern Kentucky University, Department of Physics and Geology (United States)

    2017-11-15

    Experiments were carried out on highly ordered GdAl{sub 2} samples containing extremely dilute mole fractions of{sup 111}In/Cd probe-atom solutes (about 10{sup −11}), intrinsic antisite atoms Al{sub Gd} having mole fractions of order 0-10{sup −2}, and doped with Ag solutes at mole fractions of order 10{sup −2}. Three types of defect interactions were investigated. (1) Quadrupole interactions caused by Ag-solute atoms neighboring{sup 111}In/Cd solute probe atoms were detected using the method of perturbed angular correlation of gamma rays (PAC). Three complexes of pairs of In-probes and Ag-solutes occupying neighboring positions on Gd- and Al-sublattices were identified by comparing site fractions in Gd-poor and Gd-rich GdAl{sub 2}(Ag) samples and from the symmetry of the quadrupole interactions. Interaction enthalpies between solute-atom pairs were determined from temperature dependences of observed site fractions. Repulsive interactions were observed for close-neighbor complexes In{sub Gd}+Ag{sub Gd} and In{sub Gd}+Ag{sub Al} pairs, whereas a slightly attractive interaction was observed for In{sub Al}+Ag{sub Al}. Interaction enthalpies were all small, in the range ±0.15 eV. (2) Quadrupole interactions caused by intrinsic antisite atoms Al{sub Gd} neighboring In{sub Gd} probes were also detected and site fractions measured as a function of temperature, as in previous work on samples not doped with Ag-solutes [Temperature- and composition-driven changes in site occupation of solutes in Gd{sub 1+3x}Al{sub 2−3x}, Zacate and Collins (Phys. Rev. B69, 174202 (1))]. However, the effective binding enthalpy between In{sub Gd} probe and Al{sub Gd} antisite was found to change sign from -0.12 eV (attractive interaction) in undoped samples to + 0.24 eV (repulsive) in Ag-doped samples. This may be attributed to an attractive interaction between Al{sub Gd} antisite atoms and Ag-dopants that competes with the attractive interaction between In{sub Gd} and Al{sub Gd

  15. Fock space, symbolic algebra, and analytical solutions for small stochastic systems.

    Science.gov (United States)

    Santos, Fernando A N; Gadêlha, Hermes; Gaffney, Eamonn A

    2015-12-01

    Randomness is ubiquitous in nature. From single-molecule biochemical reactions to macroscale biological systems, stochasticity permeates individual interactions and often regulates emergent properties of the system. While such systems are regularly studied from a modeling viewpoint using stochastic simulation algorithms, numerous potential analytical tools can be inherited from statistical and quantum physics, replacing randomness due to quantum fluctuations with low-copy-number stochasticity. Nevertheless, classical studies remained limited to the abstract level, demonstrating a more general applicability and equivalence between systems in physics and biology rather than exploiting the physics tools to study biological systems. Here the Fock space representation, used in quantum mechanics, is combined with the symbolic algebra of creation and annihilation operators to consider explicit solutions for the chemical master equations describing small, well-mixed, biochemical, or biological systems. This is illustrated with an exact solution for a Michaelis-Menten single enzyme interacting with limited substrate, including a consideration of very short time scales, which emphasizes when stiffness is present even for small copy numbers. Furthermore, we present a general matrix representation for Michaelis-Menten kinetics with an arbitrary number of enzymes and substrates that, following diagonalization, leads to the solution of this ubiquitous, nonlinear enzyme kinetics problem. For this, a flexible symbolic maple code is provided, demonstrating the prospective advantages of this framework compared to stochastic simulation algorithms. This further highlights the possibilities for analytically based studies of stochastic systems in biology and chemistry using tools from theoretical quantum physics.

  16. In situ microfluidic dialysis for biological small-angle X-ray scattering

    DEFF Research Database (Denmark)

    Skou, Magda; Skou, Soren; Jensen, Thomas Glasdam

    2014-01-01

    Owing to the demand for low sample consumption and automated sample changing capabilities at synchrotron small-angle X-ray (solution) scattering (SAXS) beamlines, X-ray microfluidics is receiving continuously increasing attention. Here, a remote-controlled microfluidic device is presented for sim...... in incidental sample purification. Hence, this versatile microfluidic device enables investigation of experimentally induced structural changes under dynamically controllable sample conditions. (C) 2014 International Union of Crystallography......Owing to the demand for low sample consumption and automated sample changing capabilities at synchrotron small-angle X-ray (solution) scattering (SAXS) beamlines, X-ray microfluidics is receiving continuously increasing attention. Here, a remote-controlled microfluidic device is presented...

  17. Respondent-driven sampling and the recruitment of people with small injecting networks.

    Science.gov (United States)

    Paquette, Dana; Bryant, Joanne; de Wit, John

    2012-05-01

    Respondent-driven sampling (RDS) is a form of chain-referral sampling, similar to snowball sampling, which was developed to reach hidden populations such as people who inject drugs (PWID). RDS is said to reach members of a hidden population that may not be accessible through other sampling methods. However, less attention has been paid as to whether there are segments of the population that are more likely to be missed by RDS. This study examined the ability of RDS to capture people with small injecting networks. A study of PWID, using RDS, was conducted in 2009 in Sydney, Australia. The size of participants' injecting networks was examined by recruitment chain and wave. Participants' injecting network characteristics were compared to those of participants from a separate pharmacy-based study. A logistic regression analysis was conducted to examine the characteristics independently associated with having small injecting networks, using the combined RDS and pharmacy-based samples. In comparison with the pharmacy-recruited participants, RDS participants were almost 80% less likely to have small injecting networks, after adjusting for other variables. RDS participants were also more likely to have their injecting networks form a larger proportion of those in their social networks, and to have acquaintances as part of their injecting networks. Compared to those with larger injecting networks, individuals with small injecting networks were equally likely to engage in receptive sharing of injecting equipment, but less likely to have had contact with prevention services. These findings suggest that those with small injecting networks are an important group to recruit, and that RDS is less likely to capture these individuals.

  18. ASSESSING SMALL SAMPLE WAR-GAMING DATASETS

    Directory of Open Access Journals (Sweden)

    W. J. HURLEY

    2013-10-01

    Full Text Available One of the fundamental problems faced by military planners is the assessment of changes to force structure. An example is whether to replace an existing capability with an enhanced system. This can be done directly with a comparison of measures such as accuracy, lethality, survivability, etc. However this approach does not allow an assessment of the force multiplier effects of the proposed change. To gauge these effects, planners often turn to war-gaming. For many war-gaming experiments, it is expensive, both in terms of time and dollars, to generate a large number of sample observations. This puts a premium on the statistical methodology used to examine these small datasets. In this paper we compare the power of three tests to assess population differences: the Wald-Wolfowitz test, the Mann-Whitney U test, and re-sampling. We employ a series of Monte Carlo simulation experiments. Not unexpectedly, we find that the Mann-Whitney test performs better than the Wald-Wolfowitz test. Resampling is judged to perform slightly better than the Mann-Whitney test.

  19. Estimation of reference intervals from small samples: an example using canine plasma creatinine.

    Science.gov (United States)

    Geffré, A; Braun, J P; Trumel, C; Concordet, D

    2009-12-01

    According to international recommendations, reference intervals should be determined from at least 120 reference individuals, which often are impossible to achieve in veterinary clinical pathology, especially for wild animals. When only a small number of reference subjects is available, the possible bias cannot be known and the normality of the distribution cannot be evaluated. A comparison of reference intervals estimated by different methods could be helpful. The purpose of this study was to compare reference limits determined from a large set of canine plasma creatinine reference values, and large subsets of this data, with estimates obtained from small samples selected randomly. Twenty sets each of 120 and 27 samples were randomly selected from a set of 1439 plasma creatinine results obtained from healthy dogs in another study. Reference intervals for the whole sample and for the large samples were determined by a nonparametric method. The estimated reference limits for the small samples were minimum and maximum, mean +/- 2 SD of native and Box-Cox-transformed values, 2.5th and 97.5th percentiles by a robust method on native and Box-Cox-transformed values, and estimates from diagrams of cumulative distribution functions. The whole sample had a heavily skewed distribution, which approached Gaussian after Box-Cox transformation. The reference limits estimated from small samples were highly variable. The closest estimates to the 1439-result reference interval for 27-result subsamples were obtained by both parametric and robust methods after Box-Cox transformation but were grossly erroneous in some cases. For small samples, it is recommended that all values be reported graphically in a dot plot or histogram and that estimates of the reference limits be compared using different methods.

  20. Accelerator mass spectrometry of ultra-small samples with applications in the biosciences

    International Nuclear Information System (INIS)

    Salehpour, Mehran; Håkansson, Karl; Possnert, Göran

    2013-01-01

    An overview is presented covering the biological accelerator mass spectrometry activities at Uppsala University. The research utilizes the Uppsala University Tandem laboratory facilities, including a 5 MV Pelletron tandem accelerator and two stable isotope ratio mass spectrometers. In addition, a dedicated sample preparation laboratory for biological samples with natural activity is in use, as well as another laboratory specifically for 14 C-labeled samples. A variety of ongoing projects are described and presented. Examples are: (1) Ultra-small sample AMS. We routinely analyze samples with masses in the 5–10 μg C range. Data is presented regarding the sample preparation method, (2) bomb peak biological dating of ultra-small samples. A long term project is presented where purified and cell-specific DNA from various part of the human body including the heart and the brain are analyzed with the aim of extracting regeneration rate of the various human cells, (3) biological dating of various human biopsies, including atherosclerosis related plaques is presented. The average built up time of the surgically removed human carotid plaques have been measured and correlated to various data including the level of insulin in the human blood, and (4) In addition to standard microdosing type measurements using small pharmaceutical drugs, pre-clinical pharmacokinetic data from a macromolecular drug candidate are discussed.

  1. Accelerator mass spectrometry of ultra-small samples with applications in the biosciences

    Energy Technology Data Exchange (ETDEWEB)

    Salehpour, Mehran, E-mail: mehran.salehpour@physics.uu.se [Department of Physics and Astronomy, Ion Physics, PO Box 516, SE-751 20 Uppsala (Sweden); Hakansson, Karl; Possnert, Goeran [Department of Physics and Astronomy, Ion Physics, PO Box 516, SE-751 20 Uppsala (Sweden)

    2013-01-15

    An overview is presented covering the biological accelerator mass spectrometry activities at Uppsala University. The research utilizes the Uppsala University Tandem laboratory facilities, including a 5 MV Pelletron tandem accelerator and two stable isotope ratio mass spectrometers. In addition, a dedicated sample preparation laboratory for biological samples with natural activity is in use, as well as another laboratory specifically for {sup 14}C-labeled samples. A variety of ongoing projects are described and presented. Examples are: (1) Ultra-small sample AMS. We routinely analyze samples with masses in the 5-10 {mu}g C range. Data is presented regarding the sample preparation method, (2) bomb peak biological dating of ultra-small samples. A long term project is presented where purified and cell-specific DNA from various part of the human body including the heart and the brain are analyzed with the aim of extracting regeneration rate of the various human cells, (3) biological dating of various human biopsies, including atherosclerosis related plaques is presented. The average built up time of the surgically removed human carotid plaques have been measured and correlated to various data including the level of insulin in the human blood, and (4) In addition to standard microdosing type measurements using small pharmaceutical drugs, pre-clinical pharmacokinetic data from a macromolecular drug candidate are discussed.

  2. Transportable high sensitivity small sample radiometric calorimeter

    International Nuclear Information System (INIS)

    Wetzel, J.R.; Biddle, R.S.; Cordova, B.S.; Sampson, T.E.; Dye, H.R.; McDow, J.G.

    1998-01-01

    A new small-sample, high-sensitivity transportable radiometric calorimeter, which can be operated in different modes, contains an electrical calibration method, and can be used to develop secondary standards, will be described in this presentation. The data taken from preliminary tests will be presented to indicate the precision and accuracy of the instrument. The calorimeter and temperature-controlled bath, at present, require only a 30-in. by 20-in. tabletop area. The calorimeter is operated from a laptop computer system using unique measurement module capable of monitoring all necessary calorimeter signals. The calorimeter can be operated in the normal calorimeter equilibration mode, as a comparison instrument, using twin chambers and an external electrical calibration method. The sample chamber is 0.75 in (1.9 cm) in diameter by 2.5 in. (6.35 cm) long. This size will accommodate most 238 Pu heat standards manufactured in the past. The power range runs from 0.001 W to <20 W. The high end is only limited by sample size

  3. EDXRF applied to the chemical element determination of small invertebrate samples

    International Nuclear Information System (INIS)

    Magalhaes, Marcelo L.R.; Santos, Mariana L.O.; Cantinha, Rebeca S.; Souza, Thomas Marques de; Franca, Elvis J. de

    2015-01-01

    Energy Dispersion X-Ray Fluorescence - EDXRF is a fast analytical technique of easy operation, however demanding reliable analytical curves due to the intrinsic matrix dependence and interference during the analysis. By using biological materials of diverse matrices, multielemental analytical protocols can be implemented and a group of chemical elements could be determined in diverse biological matrices depending on the chemical element concentration. Particularly for invertebrates, EDXRF presents some advantages associated to the possibility of the analysis of small size samples, in which a collimator can be used that directing the incidence of X-rays to a small surface of the analyzed samples. In this work, EDXRF was applied to determine Cl, Fe, P, S and Zn in invertebrate samples using the collimator of 3 mm and 10 mm. For the assessment of the analytical protocol, the SRM 2976 Trace Elements in Mollusk produced and SRM 8415 Whole Egg Powder by the National Institute of Standards and Technology - NIST were also analyzed. After sampling by using pitfall traps, invertebrate were lyophilized, milled and transferred to polyethylene vials covered by XRF polyethylene. Analyses were performed at atmosphere lower than 30 Pa, varying voltage and electric current according to the chemical element to be analyzed. For comparison, Zn in the invertebrate material was also quantified by graphite furnace atomic absorption spectrometry after acid treatment (mixture of nitric acid and hydrogen peroxide) of samples have. Compared to the collimator of 10 mm, the SRM 2976 and SRM 8415 results obtained by the 3 mm collimator agreed well at the 95% confidence level since the E n Number were in the range of -1 and 1. Results from GFAAS were in accordance to the EDXRF values for composite samples. Therefore, determination of some chemical elements by EDXRF can be recommended for very small invertebrate samples (lower than 100 mg) with advantage of preserving the samples. (author)

  4. Nano-Scale Sample Acquisition Systems for Small Class Exploration Spacecraft

    Science.gov (United States)

    Paulsen, G.

    2015-12-01

    The paradigm for space exploration is changing. Large and expensive missions are very rare and the space community is turning to smaller, lighter, and less expensive missions that could still perform great exploration. These missions are also within reach of commercial companies such as the Google Lunar X Prize teams that develop small scale lunar missions. Recent commercial endeavors such as "Planet Labs inc." and Sky Box Imaging, inc. show that there are new benefits and business models associated with miniaturization of space hardware. The Nano-Scale Sample Acquisition System includes NanoDrill for capture of small rock cores and PlanetVac for capture of surface regolith. These two systems are part of the ongoing effort to develop "Micro Sampling" systems for deployment by the small spacecraft with limited payload capacities. The ideal applications include prospecting missions to the Moon and Asteroids. The MicroDrill is a rotary-percussive coring drill that captures cores 7 mm in diameter and up to 2 cm long. The drill weighs less than 1 kg and can capture a core from a 40 MPa strength rock within a few minutes, with less than 10 Watt power and less than 10 Newton of preload. The PlanetVac is a pneumatic based regolith acquisition system that can capture surface sample in touch-and-go maneuver. These sampling systems were integrated within the footpads of commercial quadcopter for testing. As such, they could also be used by geologists on Earth to explore difficult to get to locations.

  5. A thermostat for precise measurements of thermoresistance of small samples

    International Nuclear Information System (INIS)

    Rusinowski, Z.; Slowinski, B.; Winiewski, R.

    1996-01-01

    In the work a simple experimental set-up is described in which special attention is paid to the important problem of the thermal stability of thermoresistance measurements of small samples of manganin

  6. Auto-validating von Neumann rejection sampling from small phylogenetic tree spaces

    Directory of Open Access Journals (Sweden)

    York Thomas

    2009-01-01

    Full Text Available Abstract Background In phylogenetic inference one is interested in obtaining samples from the posterior distribution over the tree space on the basis of some observed DNA sequence data. One of the simplest sampling methods is the rejection sampler due to von Neumann. Here we introduce an auto-validating version of the rejection sampler, via interval analysis, to rigorously draw samples from posterior distributions over small phylogenetic tree spaces. Results The posterior samples from the auto-validating sampler are used to rigorously (i estimate posterior probabilities for different rooted topologies based on mitochondrial DNA from human, chimpanzee and gorilla, (ii conduct a non-parametric test of rate variation between protein-coding and tRNA-coding sites from three primates and (iii obtain a posterior estimate of the human-neanderthal divergence time. Conclusion This solves the open problem of rigorously drawing independent and identically distributed samples from the posterior distribution over rooted and unrooted small tree spaces (3 or 4 taxa based on any multiply-aligned sequence data.

  7. A comparison of confidence/credible interval methods for the area under the ROC curve for continuous diagnostic tests with small sample size.

    Science.gov (United States)

    Feng, Dai; Cortese, Giuliana; Baumgartner, Richard

    2017-12-01

    The receiver operating characteristic (ROC) curve is frequently used as a measure of accuracy of continuous markers in diagnostic tests. The area under the ROC curve (AUC) is arguably the most widely used summary index for the ROC curve. Although the small sample size scenario is common in medical tests, a comprehensive study of small sample size properties of various methods for the construction of the confidence/credible interval (CI) for the AUC has been by and large missing in the literature. In this paper, we describe and compare 29 non-parametric and parametric methods for the construction of the CI for the AUC when the number of available observations is small. The methods considered include not only those that have been widely adopted, but also those that have been less frequently mentioned or, to our knowledge, never applied to the AUC context. To compare different methods, we carried out a simulation study with data generated from binormal models with equal and unequal variances and from exponential models with various parameters and with equal and unequal small sample sizes. We found that the larger the true AUC value and the smaller the sample size, the larger the discrepancy among the results of different approaches. When the model is correctly specified, the parametric approaches tend to outperform the non-parametric ones. Moreover, in the non-parametric domain, we found that a method based on the Mann-Whitney statistic is in general superior to the others. We further elucidate potential issues and provide possible solutions to along with general guidance on the CI construction for the AUC when the sample size is small. Finally, we illustrate the utility of different methods through real life examples.

  8. Systematic studies of small scintillators for new sampling calorimeter

    Indian Academy of Sciences (India)

    A new sampling calorimeter using very thin scintillators and the multi-pixel photon counter (MPPC) has been proposed to produce better position resolution for the international linear collider (ILC) experiment. As part of this R & D study, small plastic scintillators of different sizes, thickness and wrapping reflectors are ...

  9. LIBS detection of heavy metal elements in liquid solutions by using wood pellet as sample matrix

    International Nuclear Information System (INIS)

    Wen Guanhong; Sun Duixiong; Su Maogen; Dong Chenzhong

    2013-01-01

    Laser-induced breakdown spectroscopy (LIBS) has been applied to the analysis of heavy metals in liquid sample. A new approach was presented to improve the detection limit and minimize the sample matrix effects, in which dried wood pellets absorbed the given amounts of Cr standard solutions and then were baked because they have stronger and rapid absorption properties for liquid samples as well as simple elemental compositions. In this work, we have taken a typical heavy metal Cr element as an example, and investigated the spectral feasibility of Cr solutions and dried wood pellets before and after absorbing Cr solutions at the same experimental conditions, respectively. The results were demonstrated to successfully produce a superior analytical response for heavy metal elements by using wood pellet as sample matrix according to obtained LOD of 0.07 ppm for Cr element in solutions. (author)

  10. LIBS Detection of Heavy Metal Elements in Liquid Solutions by Using Wood Pellet as Sample Matrix

    International Nuclear Information System (INIS)

    Wen Guanhong; Sun Duixiong; Su Maogen; Dong Chenzhong

    2014-01-01

    Laser-induced breakdown spectroscopy (LIBS) has been applied to the analysis of heavy metals in liquid samples. A new approach was presented to lower the limit of detection (LOD) and minimize the sample matrix effects, in which dried wood pellets absorbed the given amounts of Cr standard solutions and then were baked because they have stronger and rapid absorption properties for liquid samples as well as simple elemental compositions. In this work, we have taken a typical heavy metal Cr element as an example, and investigated the spectral feasibility of Cr solutions and dried wood pellets before and after absorbing Cr solutions at the same experimental conditions. The results were demonstrated to successfully produce a superior analytical response for heavy metal elements by using wood pellet as sample matrix according to the obtained LOD of 0.07 ppm for Cr element in solutions

  11. Suitability of small diagnostic peripheral-blood samples for cell-therapy studies.

    Science.gov (United States)

    Stephanou, Coralea; Papasavva, Panayiota; Zachariou, Myria; Patsali, Petros; Epitropou, Marilena; Ladas, Petros; Al-Abdulla, Ruba; Christou, Soteroulla; Antoniou, Michael N; Lederer, Carsten W; Kleanthous, Marina

    2017-02-01

    Primary hematopoietic stem and progenitor cells (HSPCs) are key components of cell-based therapies for blood disorders and are thus the authentic substrate for related research. We propose that ubiquitous small-volume diagnostic samples represent a readily available and as yet untapped resource of primary patient-derived cells for cell- and gene-therapy studies. In the present study we compare isolation and storage methods for HSPCs from normal and thalassemic small-volume blood samples, considering genotype, density-gradient versus lysis-based cell isolation and cryostorage media with different serum contents. Downstream analyses include viability, recovery, differentiation in semi-solid media and performance in liquid cultures and viral transductions. We demonstrate that HSPCs isolated either by ammonium-chloride potassium (ACK)-based lysis or by gradient isolation are suitable for functional analyses in clonogenic assays, high-level HSPC expansion and efficient lentiviral transduction. For cryostorage of cells, gradient isolation is superior to ACK lysis, and cryostorage in freezing media containing 50% fetal bovine serum demonstrated good results across all tested criteria. For assays on freshly isolated cells, ACK lysis performed similar to, and for thalassemic samples better than, gradient isolation, at a fraction of the cost and hands-on time. All isolation and storage methods show considerable variation within sample groups, but this is particularly acute for density gradient isolation of thalassemic samples. This study demonstrates the suitability of small-volume blood samples for storage and preclinical studies, opening up the research field of HSPC and gene therapy to any blood diagnostic laboratory with corresponding bioethics approval for experimental use of surplus material. Copyright © 2017 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

  12. A Third Moment Adjusted Test Statistic for Small Sample Factor Analysis.

    Science.gov (United States)

    Lin, Johnny; Bentler, Peter M

    2012-01-01

    Goodness of fit testing in factor analysis is based on the assumption that the test statistic is asymptotically chi-square; but this property may not hold in small samples even when the factors and errors are normally distributed in the population. Robust methods such as Browne's asymptotically distribution-free method and Satorra Bentler's mean scaling statistic were developed under the presumption of non-normality in the factors and errors. This paper finds new application to the case where factors and errors are normally distributed in the population but the skewness of the obtained test statistic is still high due to sampling error in the observed indicators. An extension of Satorra Bentler's statistic is proposed that not only scales the mean but also adjusts the degrees of freedom based on the skewness of the obtained test statistic in order to improve its robustness under small samples. A simple simulation study shows that this third moment adjusted statistic asymptotically performs on par with previously proposed methods, and at a very small sample size offers superior Type I error rates under a properly specified model. Data from Mardia, Kent and Bibby's study of students tested for their ability in five content areas that were either open or closed book were used to illustrate the real-world performance of this statistic.

  13. A General Linear Method for Equating with Small Samples

    Science.gov (United States)

    Albano, Anthony D.

    2015-01-01

    Research on equating with small samples has shown that methods with stronger assumptions and fewer statistical estimates can lead to decreased error in the estimated equating function. This article introduces a new approach to linear observed-score equating, one which provides flexible control over how form difficulty is assumed versus estimated…

  14. Biota dose assessment of small mammals sampled near uranium mines in northern Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Jannik, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Minter, K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Kuhne, W. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Kubilius, W. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2018-01-09

    In 2015, the U. S. Geological Survey (USGS) collected approximately 50 small mammal carcasses from Northern Arizona uranium mines and other background locations. Based on the highest gross alpha results, 11 small mammal samples were selected for radioisotopic analyses. None of the background samples had significant gross alpha results. The 11 small mammals were identified relative to the three ‘indicator’ mines located south of Fredonia, AZ on the Kanab Plateau (Kanab North Mine, Pinenut Mine, and Arizona 1 Mine) (Figure 1-1) and are operated by Energy Fuels Resources Inc. (EFRI). EFRI annually reports soil analysis for uranium and radium-226 using Arizona Department of Environmental Quality (ADEQ)-approved Standard Operating Procedures for Soil Sampling (EFRI 2016a, 2016b, 2017). In combination with the USGS small mammal radioiosotopic tissue analyses, a biota dose assessment was completed by Savannah River National Laboratory (SRNL) using the RESidual RADioactivity-BIOTA (RESRAD-BIOTA, V. 1.8) dose assessment tool provided by the Argonne National Laboratory (ANL 2017).

  15. Automated Sampling and Extraction of Krypton from Small Air Samples for Kr-85 Measurement Using Atom Trap Trace Analysis

    International Nuclear Information System (INIS)

    Hebel, S.; Hands, J.; Goering, F.; Kirchner, G.; Purtschert, R.

    2015-01-01

    Atom-Trap-Trace-Analysis (ATTA) provides the capability of measuring the Krypton-85 concentration in microlitre amounts of krypton extracted from air samples of about 1 litre. This sample size is sufficiently small to allow for a range of applications, including on-site spot sampling and continuous sampling over periods of several hours. All samples can be easily handled and transported to an off-site laboratory for ATTA measurement, or stored and analyzed on demand. Bayesian sampling methodologies can be applied by blending samples for bulk measurement and performing in-depth analysis as required. Prerequisite for measurement is the extraction of a pure krypton fraction from the sample. This paper introduces an extraction unit able to isolate the krypton in small ambient air samples with high speed, high efficiency and in a fully automated manner using a combination of cryogenic distillation and gas chromatography. Air samples are collected using an automated smart sampler developed in-house to achieve a constant sampling rate over adjustable time periods ranging from 5 minutes to 3 hours per sample. The smart sampler can be deployed in the field and operate on battery for one week to take up to 60 air samples. This high flexibility of sampling and the fast, robust sample preparation are a valuable tool for research and the application of Kr-85 measurements to novel Safeguards procedures. (author)

  16. EDXRF applied to the chemical element determination of small invertebrate samples

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, Marcelo L.R.; Santos, Mariana L.O.; Cantinha, Rebeca S.; Souza, Thomas Marques de; Franca, Elvis J. de, E-mail: marcelo_rlm@hotmail.com, E-mail: marianasantos_ufpe@hotmail.com, E-mail: rebecanuclear@gmail.com, E-mail: thomasmarques@live.com.pt, E-mail: ejfranca@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2015-07-01

    Energy Dispersion X-Ray Fluorescence - EDXRF is a fast analytical technique of easy operation, however demanding reliable analytical curves due to the intrinsic matrix dependence and interference during the analysis. By using biological materials of diverse matrices, multielemental analytical protocols can be implemented and a group of chemical elements could be determined in diverse biological matrices depending on the chemical element concentration. Particularly for invertebrates, EDXRF presents some advantages associated to the possibility of the analysis of small size samples, in which a collimator can be used that directing the incidence of X-rays to a small surface of the analyzed samples. In this work, EDXRF was applied to determine Cl, Fe, P, S and Zn in invertebrate samples using the collimator of 3 mm and 10 mm. For the assessment of the analytical protocol, the SRM 2976 Trace Elements in Mollusk produced and SRM 8415 Whole Egg Powder by the National Institute of Standards and Technology - NIST were also analyzed. After sampling by using pitfall traps, invertebrate were lyophilized, milled and transferred to polyethylene vials covered by XRF polyethylene. Analyses were performed at atmosphere lower than 30 Pa, varying voltage and electric current according to the chemical element to be analyzed. For comparison, Zn in the invertebrate material was also quantified by graphite furnace atomic absorption spectrometry after acid treatment (mixture of nitric acid and hydrogen peroxide) of samples have. Compared to the collimator of 10 mm, the SRM 2976 and SRM 8415 results obtained by the 3 mm collimator agreed well at the 95% confidence level since the E{sub n} Number were in the range of -1 and 1. Results from GFAAS were in accordance to the EDXRF values for composite samples. Therefore, determination of some chemical elements by EDXRF can be recommended for very small invertebrate samples (lower than 100 mg) with advantage of preserving the samples. (author)

  17. Evaluation of solution stability for two-component polydisperse systems by small-angle scattering

    Science.gov (United States)

    Kryukova, A. E.; Konarev, P. V.; Volkov, V. V.

    2017-12-01

    The article is devoted to the modelling of small-angle scattering data using the program MIXTURE designed for the study of polydisperse multicomponent mixtures. In this work we present the results of solution stability studies for theoretical small-angle scattering data sets from two-component models. It was demonstrated that the addition of the noise to the data influences the stability range of the restored structural parameters. The recommendations for the optimal minimization schemes that permit to restore the volume size distributions for polydisperse systems are suggested.

  18. Line printing solution-processable small molecules with uniform surface profile via ink-jet printer.

    Science.gov (United States)

    Liu, Huimin; Xu, Wei; Tan, Wanyi; Zhu, Xuhui; Wang, Jian; Peng, Junbiao; Cao, Yong

    2016-03-01

    Line printing offers a feasible approach to remove the pixel well structure which is widely used to confine the ink-jet printed solution. In the study, a uniform line is printed by an ink-jet printer. To achieve a uniform surface profile of the printed line, 10vol% low-volatile solvent DMA (3,4-Dimethylanisole) is mixed with high-volatile solvent Pxy (p-xylene) as the solvent. After a solution-processable small molecule is dissolved, the surface tension of DMA solution becomes lower than that of Pxy solution, which creates an inward Marangoni flow during the solvent evaporation. The inward Marangoni flow balances out the outward capillary flow, thereby forming a flat film surface. The line width of the printed line depends on the contact angle of the solution on the hole injection layer. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Privacy problems in the small sample selection

    Directory of Open Access Journals (Sweden)

    Loredana Cerbara

    2013-05-01

    Full Text Available The side of social research that uses small samples for the production of micro data, today finds some operating difficulties due to the privacy law. The privacy code is a really important and necessary law because it guarantees the Italian citizen’s rights, as already happens in other Countries of the world. However it does not seem appropriate to limit once more the possibilities of the data production of the national centres of research. That possibilities are already moreover compromised due to insufficient founds is a common problem becoming more and more frequent in the research field. It would be necessary, therefore, to include in the law the possibility to use telephonic lists to select samples useful for activities directly of interest and importance to the citizen, such as the collection of the data carried out on the basis of opinion polls by the centres of research of the Italian CNR and some universities.

  20. NMR and molecular dynamics of small solutes in liquid crystals

    International Nuclear Information System (INIS)

    Luyten, P.R.

    1984-01-01

    NMR relaxation measurements, using a wide variety of modern pulse techniques, can yield valuable information about molecular motions. In this thesis the applicability of theories developed to describe spin relaxation phenomena in partially ordered media is studied for small solutes in liquid crystals. 1 H, 2 H, 13 C and 14 N relaxation measurements are interpreted by means of a model, in which fast anisotropic re-orientational motion in an orienting potential combined with contributions from cooperative fluctuations in the surrounding liquid crystal molecules, induce the observed frequency dependent relaxation behavior. (orig.)

  1. Radiocarbon measurements of small gaseous samples at CologneAMS

    Science.gov (United States)

    Stolz, A.; Dewald, A.; Altenkirch, R.; Herb, S.; Heinze, S.; Schiffer, M.; Feuerstein, C.; Müller-Gatermann, C.; Wotte, A.; Rethemeyer, J.; Dunai, T.

    2017-09-01

    A second SO-110 B (Arnold et al., 2010) ion source was installed at the 6 MV CologneAMS for the measurement of gaseous samples. For the gas supply a dedicated device from Ionplus AG was connected to the ion source. Special effort was devoted to determine optimized operation parameters for the ion source, which give a high carbon current output and a high 14C- yield. The latter is essential in cases when only small samples are available. Additionally a modified immersion lens and modified target pieces were tested and the target position was optimized.

  2. A multi-dimensional sampling method for locating small scatterers

    International Nuclear Information System (INIS)

    Song, Rencheng; Zhong, Yu; Chen, Xudong

    2012-01-01

    A multiple signal classification (MUSIC)-like multi-dimensional sampling method (MDSM) is introduced to locate small three-dimensional scatterers using electromagnetic waves. The indicator is built with the most stable part of signal subspace of the multi-static response matrix on a set of combinatorial sampling nodes inside the domain of interest. It has two main advantages compared to the conventional MUSIC methods. First, the MDSM is more robust against noise. Second, it can work with a single incidence even for multi-scatterers. Numerical simulations are presented to show the good performance of the proposed method. (paper)

  3. The Accuracy of Inference in Small Samples of Dynamic Panel Data Models

    NARCIS (Netherlands)

    Bun, M.J.G.; Kiviet, J.F.

    2001-01-01

    Through Monte Carlo experiments the small sample behavior is examined of various inference techniques for dynamic panel data models when both the time-series and cross-section dimensions of the data set are small. The LSDV technique and corrected versions of it are compared with IV and GMM

  4. Ambipolar Small-Molecule:Polymer Blend Semiconductors for Solution-Processable Organic Field-Effect Transistors.

    Science.gov (United States)

    Kang, Minji; Hwang, Hansu; Park, Won-Tae; Khim, Dongyoon; Yeo, Jun-Seok; Kim, Yunseul; Kim, Yeon-Ju; Noh, Yong-Young; Kim, Dong-Yu

    2017-01-25

    We report on the fabrication of an organic thin-film semiconductor formed using a blend solution of soluble ambipolar small molecules and an insulating polymer binder that exhibits vertical phase separation and uniform film formation. The semiconductor thin films are produced in a single step from a mixture containing a small molecular semiconductor, namely, quinoidal biselenophene (QBS), and a binder polymer, namely, poly(2-vinylnaphthalene) (PVN). Organic field-effect transistors (OFETs) based on QBS/PVN blend semiconductor are then assembled using top-gate/bottom-contact device configuration, which achieve almost four times higher mobility than the neat QBS semiconductor. Depth profile via secondary ion mass spectrometry and atomic force microscopy images indicate that the QBS domains in the films made from the blend are evenly distributed with a smooth morphology at the bottom of the PVN layer. Bias stress test and variable-temperature measurements on QBS-based OFETs reveal that the QBS/PVN blend semiconductor remarkably reduces the number of trap sites at the gate dielectric/semiconductor interface and the activation energy in the transistor channel. This work provides a one-step solution processing technique, which makes use of soluble ambipolar small molecules to form a thin-film semiconductor for application in high-performance OFETs.

  5. On the Structure of Cortical Microcircuits Inferred from Small Sample Sizes.

    Science.gov (United States)

    Vegué, Marina; Perin, Rodrigo; Roxin, Alex

    2017-08-30

    The structure in cortical microcircuits deviates from what would be expected in a purely random network, which has been seen as evidence of clustering. To address this issue, we sought to reproduce the nonrandom features of cortical circuits by considering several distinct classes of network topology, including clustered networks, networks with distance-dependent connectivity, and those with broad degree distributions. To our surprise, we found that all of these qualitatively distinct topologies could account equally well for all reported nonrandom features despite being easily distinguishable from one another at the network level. This apparent paradox was a consequence of estimating network properties given only small sample sizes. In other words, networks that differ markedly in their global structure can look quite similar locally. This makes inferring network structure from small sample sizes, a necessity given the technical difficulty inherent in simultaneous intracellular recordings, problematic. We found that a network statistic called the sample degree correlation (SDC) overcomes this difficulty. The SDC depends only on parameters that can be estimated reliably given small sample sizes and is an accurate fingerprint of every topological family. We applied the SDC criterion to data from rat visual and somatosensory cortex and discovered that the connectivity was not consistent with any of these main topological classes. However, we were able to fit the experimental data with a more general network class, of which all previous topologies were special cases. The resulting network topology could be interpreted as a combination of physical spatial dependence and nonspatial, hierarchical clustering. SIGNIFICANCE STATEMENT The connectivity of cortical microcircuits exhibits features that are inconsistent with a simple random network. Here, we show that several classes of network models can account for this nonrandom structure despite qualitative differences in

  6. inverse gaussian model for small area estimation via gibbs sampling

    African Journals Online (AJOL)

    ADMIN

    For example, MacGibbon and Tomberlin. (1989) have considered estimating small area rates and binomial parameters using empirical Bayes methods. Stroud (1991) used hierarchical Bayes approach for univariate natural exponential families with quadratic variance functions in sample survey applications, while Chaubey ...

  7. Rules of attraction: The role of bait in small mammal sampling at ...

    African Journals Online (AJOL)

    Baits or lures are commonly used for surveying small mammal communities, not only because they attract large numbers of these animals, but also because they provide sustenance for trapped individuals. In this study we used Sherman live traps with five bait treatments to sample small mammal populations at three ...

  8. Self-interacting inelastic dark matter: a viable solution to the small scale structure problems

    Energy Technology Data Exchange (ETDEWEB)

    Blennow, Mattias; Clementz, Stefan; Herrero-Garcia, Juan, E-mail: emb@kth.se, E-mail: scl@kth.se, E-mail: juan.herrero-garcia@adelaide.edu.au [Department of Physics, School of Engineering Sciences, KTH Royal Institute of Technology, AlbaNova University Center, 106 91 Stockholm (Sweden)

    2017-03-01

    Self-interacting dark matter has been proposed as a solution to the small-scale structure problems, such as the observed flat cores in dwarf and low surface brightness galaxies. If scattering takes place through light mediators, the scattering cross section relevant to solve these problems may fall into the non-perturbative regime leading to a non-trivial velocity dependence, which allows compatibility with limits stemming from cluster-size objects. However, these models are strongly constrained by different observations, in particular from the requirements that the decay of the light mediator is sufficiently rapid (before Big Bang Nucleosynthesis) and from direct detection. A natural solution to reconcile both requirements are inelastic endothermic interactions, such that scatterings in direct detection experiments are suppressed or even kinematically forbidden if the mass splitting between the two-states is sufficiently large. Using an exact solution when numerically solving the Schrödinger equation, we study such scenarios and find regions in the parameter space of dark matter and mediator masses, and the mass splitting of the states, where the small scale structure problems can be solved, the dark matter has the correct relic abundance and direct detection limits can be evaded.

  9. Uncertainty budget in internal monostandard NAA for small and large size samples analysis

    International Nuclear Information System (INIS)

    Dasari, K.B.; Acharya, R.

    2014-01-01

    Total uncertainty budget evaluation on determined concentration value is important under quality assurance programme. Concentration calculation in NAA or carried out by relative NAA and k0 based internal monostandard NAA (IM-NAA) method. IM-NAA method has been used for small and large sample analysis of clay potteries. An attempt was made to identify the uncertainty components in IM-NAA and uncertainty budget for La in both small and large size samples has been evaluated and compared. (author)

  10. Thermal neutron absorption cross section of small samples

    International Nuclear Information System (INIS)

    Nghiep, T.D.; Vinh, T.T.; Son, N.N.; Vuong, T.V.; Hung, N.T.

    1989-01-01

    A modified steady method for determining the macroscopic thermal neutron absorption cross section of small samples 500 cm 3 in volume is described. The method uses a moderating block of paraffin, Pu-Be neutron source emitting 1.1x10 6 n.s. -1 , SNM-14 counter and ordinary counting equipment. The interval of cross section from 2.6 to 1.3x10 4 (10 -3 cm 2 g -1 ) was measured. The experimental data are described by calculation formulae. 7 refs.; 4 figs

  11. Segment-segment interactions of poly(N-isopropylacrylamide) in aqueous methanol solutions by using small-angle scattering

    International Nuclear Information System (INIS)

    Shimizu, S.; Kurita, K.; Furusaka, M.

    2002-01-01

    Small-angle neutron and X-ray scattering from semidilute solutions of poly(N-isopropylacrylamide) in D 2 O, methanol and methanol-water mixtures has been measured in the poor solvent regime. The binary and the ternary cluster integrals of polymer segments were determined from the concentration dependence of the correlation length at several temperatures just below the lower critical solution temperature. Then, contributions of segment-segment interactions to the entropy and the enthalpy have been calculated from the temperature dependence of interaction parameters and it has been found that both values are positive in the D 2 O and the methanol-water systems at a small content of methanol, while both values are negative in the other system. (orig.)

  12. Inverse problems with non-trivial priors: efficient solution through sequential Gibbs sampling

    DEFF Research Database (Denmark)

    Hansen, Thomas Mejer; Cordua, Knud Skou; Mosegaard, Klaus

    2012-01-01

    Markov chain Monte Carlo methods such as the Gibbs sampler and the Metropolis algorithm can be used to sample solutions to non-linear inverse problems. In principle, these methods allow incorporation of prior information of arbitrary complexity. If an analytical closed form description of the prior...... is available, which is the case when the prior can be described by a multidimensional Gaussian distribution, such prior information can easily be considered. In reality, prior information is often more complex than can be described by the Gaussian model, and no closed form expression of the prior can be given....... We propose an algorithm, called sequential Gibbs sampling, allowing the Metropolis algorithm to efficiently incorporate complex priors into the solution of an inverse problem, also for the case where no closed form description of the prior exists. First, we lay out the theoretical background...

  13. System for sampling liquids in small jugs obturated by screwed taps

    International Nuclear Information System (INIS)

    Besnier, J.

    1995-01-01

    This invention describes a machine which samples automatically liquids in small jugs obturated by screwed taps. This device can be situated in an isolated room in order to work with radioactive liquids. The machine can be divided in three main parts: a module to catch the jug, in order to take and fix it, a module to open and to close it, and a module to sample. The later takes the liquid thanks to a suction device and puts it in a container, in order to analyse the sample. (TEC)

  14. Research of pneumatic control transmission system for small irradiation samples

    International Nuclear Information System (INIS)

    Bai Zhongxiong; Zhang Haibing; Rong Ru; Zhang Tao

    2008-01-01

    In order to reduce the absorbed dose damage for the operator, pneumatic control has been adopted to realize the rapid transmission of small irradiation samples. On/off of pneumatic circuit and directions for the rapid transmission system are controlled by the electrical control part. The main program initializes the system and detects the location of the manual/automatic change-over switch, and call for the corresponding subprogram to achieve the automatic or manual operation. Automatic subprogram achieves the automatic sample transmission; Manual subprogram completes the deflation, and back and forth movement of the radiation samples. This paper introduces in detail the implementation of the system, in terms of both hardware and software design. (authors)

  15. Small Modular Reactors for Countries with Small to Medium Electric Grids - An Economically Sensible Solution

    International Nuclear Information System (INIS)

    Young, P.

    2012-01-01

    There has recently been a renewed interest throughout the world in small nuclear units for generating electricity and for other applications. A report by the World Nuclear Association discussing the advantages of small modular nuclear reactors (SMRs) over traditional nuclear reactor designs, states that ''modern small reactors for power generation are expected to have greater simplicity of design, economy of mass production, and reduced siting costs. Many are also designed for a high level of passive or inherent safety in the event of malfunction.'' Since the inception of nuclear power, the size of reactor units has grown from under 100 MWe to more than 1600 MWe. Today, due partly to the high capital cost of large power reactors and partly to the need to service small electricity grids, there is a move to develop smaller units. These may be built individually or as modules in a larger plant. SMRs are a good fit in markets where anticipated electricity demand is projected to increase incrementally, because SMRs could be built in series as needed. SMRs might be particularly attractive in countries that currently rely on diesel generators for producing electricity. Small reactors could make economic sense because of the high cost of diesel generation compared to the low marginal cost of producing electricity from nuclear energy. (Keeping in mind the initial investment costs and the need to establish a national regulatory program.) Some SMR designs are fabricated in a factory and then delivered to the site. This could be a solution for markets that lack the qualified engineers and skilled craft workers needed to construct large reactors on site. This paper will provide an overview of the types and attributes of SMRs in use or under development worldwide, describe the similarities and important differences between designs, discuss potential applications for SMRs, including baseload electricity generation, electricity generation for remote locations and areas with

  16. Small Sample Properties of Bayesian Multivariate Autoregressive Time Series Models

    Science.gov (United States)

    Price, Larry R.

    2012-01-01

    The aim of this study was to compare the small sample (N = 1, 3, 5, 10, 15) performance of a Bayesian multivariate vector autoregressive (BVAR-SEM) time series model relative to frequentist power and parameter estimation bias. A multivariate autoregressive model was developed based on correlated autoregressive time series vectors of varying…

  17. Soybean yield modeling using bootstrap methods for small samples

    Energy Technology Data Exchange (ETDEWEB)

    Dalposso, G.A.; Uribe-Opazo, M.A.; Johann, J.A.

    2016-11-01

    One of the problems that occur when working with regression models is regarding the sample size; once the statistical methods used in inferential analyzes are asymptotic if the sample is small the analysis may be compromised because the estimates will be biased. An alternative is to use the bootstrap methodology, which in its non-parametric version does not need to guess or know the probability distribution that generated the original sample. In this work we used a set of soybean yield data and physical and chemical soil properties formed with fewer samples to determine a multiple linear regression model. Bootstrap methods were used for variable selection, identification of influential points and for determination of confidence intervals of the model parameters. The results showed that the bootstrap methods enabled us to select the physical and chemical soil properties, which were significant in the construction of the soybean yield regression model, construct the confidence intervals of the parameters and identify the points that had great influence on the estimated parameters. (Author)

  18. A cell transportation solution that preserves live circulating tumor cells in patient blood samples

    International Nuclear Information System (INIS)

    Stefansson, Steingrimur; Adams, Daniel L.; Ershler, William B.; Le, Huyen; Ho, David H.

    2016-01-01

    Circulating tumor cells (CTCs) are typically collected into CellSave fixative tubes, which kills the cells, but preserves their morphology. Currently, the clinical utility of CTCs is mostly limited to their enumeration. More detailed investigation of CTC biology can be performed on live cells, but obtaining live CTCs is technically challenging, requiring blood collection into biocompatible solutions and rapid isolation which limits transportation options. To overcome the instability of CTCs, we formulated a sugar based cell transportation solution (SBTS) that stabilizes cell viability at ambient temperature. In this study we examined the long term viability of human cancer cell lines, primary cells and CTCs in human blood samples in the SBTS for transportation purposes. Four cell lines, 5 primary human cells and purified human PBMCs were tested to determine the viability of cells stored in the transportation solution at ambient temperature for up to 7 days. We then demonstrated viability of MCF-7 cells spiked into normal blood with SBTS and stored for up to 7 days. A pilot study was then run on blood samples from 3 patients with metastatic malignancies stored with or without SBTS for 6 days. CTCs were then purified by Ficoll separation/microfilter isolation and identified using CTC markers. Cell viability was assessed using trypan blue or CellTracker™ live cell stain. Our results suggest that primary/immortalized cell lines stored in SBTS remain ~90 % viable for > 72 h. Further, MCF-7 cells spiked into whole blood remain viable when stored with SBTS for up to 7 days. Finally, live CTCs were isolated from cancer patient blood samples kept in SBTS at ambient temperature for 6 days. No CTCs were isolated from blood samples stored without SBTS. In this proof of principle pilot study we show that viability of cell lines is preserved for days using SBTS. Further, this solution can be used to store patient derived blood samples for eventual isolation of viable CTCs

  19. A cell transportation solution that preserves live circulating tumor cells in patient blood samples.

    Science.gov (United States)

    Stefansson, Steingrimur; Adams, Daniel L; Ershler, William B; Le, Huyen; Ho, David H

    2016-05-06

    Circulating tumor cells (CTCs) are typically collected into CellSave fixative tubes, which kills the cells, but preserves their morphology. Currently, the clinical utility of CTCs is mostly limited to their enumeration. More detailed investigation of CTC biology can be performed on live cells, but obtaining live CTCs is technically challenging, requiring blood collection into biocompatible solutions and rapid isolation which limits transportation options. To overcome the instability of CTCs, we formulated a sugar based cell transportation solution (SBTS) that stabilizes cell viability at ambient temperature. In this study we examined the long term viability of human cancer cell lines, primary cells and CTCs in human blood samples in the SBTS for transportation purposes. Four cell lines, 5 primary human cells and purified human PBMCs were tested to determine the viability of cells stored in the transportation solution at ambient temperature for up to 7 days. We then demonstrated viability of MCF-7 cells spiked into normal blood with SBTS and stored for up to 7 days. A pilot study was then run on blood samples from 3 patients with metastatic malignancies stored with or without SBTS for 6 days. CTCs were then purified by Ficoll separation/microfilter isolation and identified using CTC markers. Cell viability was assessed using trypan blue or CellTracker™ live cell stain. Our results suggest that primary/immortalized cell lines stored in SBTS remain ~90% viable for > 72 h. Further, MCF-7 cells spiked into whole blood remain viable when stored with SBTS for up to 7 days. Finally, live CTCs were isolated from cancer patient blood samples kept in SBTS at ambient temperature for 6 days. No CTCs were isolated from blood samples stored without SBTS. In this proof of principle pilot study we show that viability of cell lines is preserved for days using SBTS. Further, this solution can be used to store patient derived blood samples for eventual isolation of viable CTCs after

  20. Temperature Dependence of Charge Localization in High-Mobility, Solution-Crystallized Small Molecule Semiconductors Studied by Charge Modulation Spectroscopy

    DEFF Research Database (Denmark)

    Meneau, Aurélie Y. B.; Olivier, Yoann; Backlund, Tomas

    2016-01-01

    In solution-processable small molecule semiconductors, the extent of charge carrier wavefunction localization induced by dynamic disorder can be probed spectroscopically as a function of temperature using charge modulation spectroscopy (CMS). Here, it is shown based on combined fi eld-effect tran......In solution-processable small molecule semiconductors, the extent of charge carrier wavefunction localization induced by dynamic disorder can be probed spectroscopically as a function of temperature using charge modulation spectroscopy (CMS). Here, it is shown based on combined fi eld......-effect transistor and CMS measurements as a function of temperature that in certain molecular semiconductors, such as solution-processible pentacene, charge carriers become trapped at low temperatures in environments in which the charges become highly localized on individual molecules, while in some other molecules...

  1. TableSim--A program for analysis of small-sample categorical data.

    Science.gov (United States)

    David J. Rugg

    2003-01-01

    Documents a computer program for calculating correct P-values of 1-way and 2-way tables when sample sizes are small. The program is written in Fortran 90; the executable code runs in 32-bit Microsoft-- command line environments.

  2. Segment-segment interactions of poly(N-isopropylacrylamide) in aqueous methanol solutions by using small-angle scattering

    CERN Document Server

    Shimizu, S; Furusaka, M

    2002-01-01

    Small-angle neutron and X-ray scattering from semidilute solutions of poly(N-isopropylacrylamide) in D sub 2 O, methanol and methanol-water mixtures has been measured in the poor solvent regime. The binary and the ternary cluster integrals of polymer segments were determined from the concentration dependence of the correlation length at several temperatures just below the lower critical solution temperature. Then, contributions of segment-segment interactions to the entropy and the enthalpy have been calculated from the temperature dependence of interaction parameters and it has been found that both values are positive in the D sub 2 O and the methanol-water systems at a small content of methanol, while both values are negative in the other system. (orig.)

  3. Sample types applied for molecular diagnosis of therapeutic management of advanced non-small cell lung cancer in the precision medicine.

    Science.gov (United States)

    Han, Yanxi; Li, Jinming

    2017-10-26

    In this era of precision medicine, molecular biology is becoming increasingly significant for the diagnosis and therapeutic management of non-small cell lung cancer. The specimen as the primary element of the whole testing flow is particularly important for maintaining the accuracy of gene alteration testing. Presently, the main sample types applied in routine diagnosis are tissue and cytology biopsies. Liquid biopsies are considered as the most promising alternatives when tissue and cytology samples are not available. Each sample type possesses its own strengths and weaknesses, pertaining to the disparity of sampling, preparation and preservation procedures, the heterogeneity of inter- or intratumors, the tumor cellularity (percentage and number of tumor cells) of specimens, etc., and none of them can individually be a "one size to fit all". Therefore, in this review, we summarized the strengths and weaknesses of different sample types that are widely used in clinical practice, offered solutions to reduce the negative impact of the samples and proposed an optimized strategy for choice of samples during the entire diagnostic course. We hope to provide valuable information to laboratories for choosing optimal clinical specimens to achieve comprehensive functional genomic landscapes and formulate individually tailored treatment plans for NSCLC patients that are in advanced stages.

  4. Crystallization behavior of polyethylene on silicon wafers in solution casting processes traced by time-resolved measurements of synchrotron grazing-incidence small-angle and wide-angle X-ray scattering

    International Nuclear Information System (INIS)

    Sasaki, S; Masunaga, H; Takata, M; Itou, K; Tashiro, K; Okuda, H; Takahara, A

    2009-01-01

    Crystallization behavior of polyethylene (PE) on silicon wafers in solution casting processes has been successfully traced by time-resolved grazing-incidence small-angle and wide-angle X-ray scattering (GISWAXS) measurements utilizing synchrotron radiation. A p-xylene solution of PE kept at ca. 343 K was dropped on a silicon wafer at ca. 298 K. While the p-xylene evaporated naturally from the dropped solution sample, PE chains crystallized to be a thin film. Raman spectral measurements were performed simultaneously with the GISWAXS measurements to evaluate quantitatively the p-xylene the dropped solution contained. Grazing-incidence wide-angle X-ray scattering (GIWAXS) patterns indicated nucleation and crystal growth in the dropped solution and the following as-cast film. GIWAXS and Raman spectral data revealed that crystallization of PE was enhanced after complete evaporation of the p-xylene from the dropped solution. The [110] and [200] directions of the orthorhombic PE crystal became relatively parallel to the wafer surface with time, which implied that the flat-on lamellae with respect to the wafer surface were mainly formed in the as-cast film. On the other hand, grazing-incidence small-angle X-ray scattering (GISAXS) patterns implied formation of isolated lamellae in the dropped solution. The lamellae and amorphous might alternatively be stacked in the preferred direction perpendicular to the wafer surface. The synchrotron GISWAXS experimental method could be applied for kinetic study on hierarchical structure of polymer thin films.

  5. Evaluating the Acceptance of Cloud-Based Productivity Computer Solutions in Small and Medium Enterprises

    Science.gov (United States)

    Dominguez, Alfredo

    2013-01-01

    Cloud computing has emerged as a new paradigm for on-demand delivery and consumption of shared IT resources over the Internet. Research has predicted that small and medium organizations (SMEs) would be among the earliest adopters of cloud solutions; however, this projection has not materialized. This study set out to investigate if behavior…

  6. 75 FR 32230 - Solutions Capital I, L.P.; Notice Seeking Exemption Under Section 312 of the Small Business...

    Science.gov (United States)

    2010-06-07

    ... working capital and general corporate purposes. The financing is brought within the purview of Sec. 107... SMALL BUSINESS ADMINISTRATION [License No. 03/03-0247] Solutions Capital I, L.P.; Notice Seeking... given that Solutions Capital I, L.P., 1100 Wilson Blvd., Suite 3000, Arlington, VA 22209, a Federal...

  7. Sensitivity study of micro four-point probe measurements on small samples

    DEFF Research Database (Denmark)

    Wang, Fei; Petersen, Dirch Hjorth; Hansen, Torben Mikael

    2010-01-01

    probes than near the outer ones. The sensitive area is defined for infinite film, circular, square, and rectangular test pads, and convergent sensitivities are observed for small samples. The simulations show that the Hall sheet resistance RH in micro Hall measurements with position error suppression...

  8. Gas-driven pump for ground-water samples

    Science.gov (United States)

    Signor, Donald C.

    1978-01-01

    Observation wells installed for artificial-recharge research and other wells used in different ground-water programs are frequently cased with small-diameter steel pipe. To obtain samples from these small-diameter wells in order to monitor water quality, and to calibrate solute-transport models, a small-diameter pump with unique operating characteristics is required that causes a minimum alternation of samples during field sampling. A small-diameter gas-driven pump was designed and built to obtain water samples from wells of two-inch diameter or larger. The pump is a double-piston type with the following characteristics: (1) The water sample is isolated from the operating gas, (2) no source of electricity is ncessary, (3) operation is continuous, (4) use of compressed gas is efficient, and (5) operation is reliable over extended periods of time. Principles of operation, actual operation techniques, gas-use analyses and operating experience are described. Complete working drawings and a component list are included. Recent modifications and pump construction for high-pressure applications also are described. (Woodard-USGS)

  9. Photolysis of Periodate and Periodic Acid in Aqueous Solution

    DEFF Research Database (Denmark)

    Sehested, Knud; Kläning, U. K.

    1978-01-01

    The photochemistry of periodate and periodic acid in aqueous solution was studied (i) by quantum yield measurements at low light intensity (ii) by flash photolysis, and (iii) by photolysis of glassy samples at 77 K. The photochemical studies were supplemented with pulse radiolysis studies...... of aqueous periodate solutions and with kinetic studies using stopped-flow technique. In strongly alkaline solution the photodecomposition of periodate proceeds via formation of O– and IVI. At pH solution O3 P is formed in a small...

  10. Quantifying predictability through information theory: small sample estimation in a non-Gaussian framework

    International Nuclear Information System (INIS)

    Haven, Kyle; Majda, Andrew; Abramov, Rafail

    2005-01-01

    Many situations in complex systems require quantitative estimates of the lack of information in one probability distribution relative to another. In short term climate and weather prediction, examples of these issues might involve the lack of information in the historical climate record compared with an ensemble prediction, or the lack of information in a particular Gaussian ensemble prediction strategy involving the first and second moments compared with the non-Gaussian ensemble itself. The relative entropy is a natural way to quantify the predictive utility in this information, and recently a systematic computationally feasible hierarchical framework has been developed. In practical systems with many degrees of freedom, computational overhead limits ensemble predictions to relatively small sample sizes. Here the notion of predictive utility, in a relative entropy framework, is extended to small random samples by the definition of a sample utility, a measure of the unlikeliness that a random sample was produced by a given prediction strategy. The sample utility is the minimum predictability, with a statistical level of confidence, which is implied by the data. Two practical algorithms for measuring such a sample utility are developed here. The first technique is based on the statistical method of null-hypothesis testing, while the second is based upon a central limit theorem for the relative entropy of moment-based probability densities. These techniques are tested on known probability densities with parameterized bimodality and skewness, and then applied to the Lorenz '96 model, a recently developed 'toy' climate model with chaotic dynamics mimicking the atmosphere. The results show a detection of non-Gaussian tendencies of prediction densities at small ensemble sizes with between 50 and 100 members, with a 95% confidence level

  11. Protein crowding in solution, frozen and freeze-dried states: small-angle neutron and X-ray scattering study of lysozyme/sorbitol/water systems

    Science.gov (United States)

    Krueger, Susan; Khodadadi, Sheila; Clark, Nicholas; McAuley, Arnold; Cristiglio, Viviana; Theyencheri, Narayanan; Curtis, Joseph; Shalaev, Evgenyi

    2015-03-01

    For effective preservation, proteins are often stored as frozen solutions or in glassy states using a freeze-drying process. However, aggregation is often observed after freeze-thaw or reconstitution of freeze-dried powder and the stability of the protein is no longer assured. In this study, small-angle neutron and X-ray scattering (SANS and SAXS) have been used to investigate changes in protein-protein interaction distances of a model protein/cryoprotectant system of lysozyme/sorbitol/water, under representative pharmaceutical processing conditions. The results demonstrate the utility of SAXS and SANS methods to monitor protein crowding at different stages of freezing and drying. The SANS measurements of solution samples showed at least one protein interaction peak corresponding to an interaction distance of ~ 90 Å. In the frozen state, two protein interaction peaks were observed by SANS with corresponding interaction distances at 40 Å as well as 90 Å. On the other hand, both SAXS and SANS data for freeze-dried samples showed three peaks, suggesting interaction distances ranging from ~ 15 Å to 170 Å. Possible interpretations of these interaction peaks will be discussed, as well as the role of sorbitol as a cryoprotectant during the freezing and drying process.

  12. Influence of convection on the diffusive transport and sieving of water and small solutes across the peritoneal membrane.

    Science.gov (United States)

    Asghar, Ramzana B; Diskin, Ann M; Spanel, Patrik; Smith, David; Davies, Simon J

    2005-02-01

    The three-pore model of peritoneal membrane physiology predicts sieving of small solutes as a result of the presence of a water-exclusive pathway. The purpose of this study was to measure the diffusive and convective components of small solute transport, including water, under differing convection. Triplicate studies were performed in eight stable individuals using 2-L exchanges of bicarbonate buffered 1.36 or 3.86% glucose and icodextrin. Diffusion of water was estimated by establishing an artificial gradient of deuterated water (HDO) between blood/body water and the dialysate. (125)RISA (radio-iodinated serum albumin) was used as an intraperitoneal volume marker to determine the net ultrafiltration and reabsorption of fluid. The mass transfer area coefficient (MTAC) for HDO and solutes was estimated using the Garred and Waniewski equations. The MTAC of HDO calculated for 1.36% glucose and icodextrin were similar (36.8 versus 39.7 ml/min; P = 0.3), whereas for other solutes, values obtained using icodextrin were consistently higher (P solutes is a reflection of their sieving. The increase in the MTAC of water and urea associated with an increase in convection is most likely due to increased mixing within the interstitium.

  13. A comparison of chemical reference materials for solution calorimeters.

    Science.gov (United States)

    Ramos, Rita; Gaisford, Simon; Buckton, Graham; Royall, Paul G; Yff, Barbara T S; O'Neill, Michael A A

    2005-08-11

    Solution calorimeters are based on semi-adiabatic or isothermal heat-conduction principles and differ in the way they record data. They also have different measuring sensitivities and require different quantities of solute and solvent. As such, the choice of chemical test substance is not straightforward. Usually the dilution of KCl is recommended; it is possible to purchase a reference sample of KCl that has a certified enthalpy of solution and this standard material is usually used to test semi-adiabatic instruments. Here, we review the suitability of a range of chemical test substances (KCl, sucrose and Tris) for an isothermal heat-conduction solution calorimeter. It was found that KCl was not the best test material because its relatively high enthalpy of solution (DeltasolH) necessitated the use of small samples (2 mg), resulting in a relatively large standard deviation (sigman-1) in the values recorded (DeltasolH=17.14+/-0.49 kJ mol-1); furthermore, KCl data must be corrected to account for the effect of dilution, although the correction was found to be small (0.07 kJ mol-1) under the experimental conditions employed here. Sucrose appears to be a much more robust test material for isothermal heat-conduction instruments because its lower enthalpy of solution allows the use of much larger samples (20 mg), which minimises experimental errors. The DeltasolH value returned (6.14+/-0.08 kJ mol-1) is in excellent agreement with the literature. It is also cheap, readily available and requires minimal preparation although its widespread use would require the preparation of a certified reference sample.

  14. A review of empirical research related to the use of small quantitative samples in clinical outcome scale development.

    Science.gov (United States)

    Houts, Carrie R; Edwards, Michael C; Wirth, R J; Deal, Linda S

    2016-11-01

    There has been a notable increase in the advocacy of using small-sample designs as an initial quantitative assessment of item and scale performance during the scale development process. This is particularly true in the development of clinical outcome assessments (COAs), where Rasch analysis has been advanced as an appropriate statistical tool for evaluating the developing COAs using a small sample. We review the benefits such methods are purported to offer from both a practical and statistical standpoint and detail several problematic areas, including both practical and statistical theory concerns, with respect to the use of quantitative methods, including Rasch-consistent methods, with small samples. The feasibility of obtaining accurate information and the potential negative impacts of misusing large-sample statistical methods with small samples during COA development are discussed.

  15. System and method for laser assisted sample transfer to solution for chemical analysis

    Science.gov (United States)

    Van Berkel, Gary J; Kertesz, Vilmos

    2014-01-28

    A system and method for laser desorption of an analyte from a specimen and capturing of the analyte in a suspended solvent to form a testing solution are described. The method can include providing a specimen supported by a desorption region of a specimen stage and desorbing an analyte from a target site of the specimen with a laser beam centered at a radiation wavelength (.lamda.). The desorption region is transparent to the radiation wavelength (.lamda.) and the sampling probe and a laser source emitting the laser beam are on opposite sides of a primary surface of the specimen stage. The system can also be arranged where the laser source and the sampling probe are on the same side of a primary surface of the specimen stage. The testing solution can then be analyzed using an analytical instrument or undergo further processing.

  16. A DFT study of the stability of SIAs and small SIA clusters in the vicinity of solute atoms in Fe

    Science.gov (United States)

    Becquart, C. S.; Ngayam Happy, R.; Olsson, P.; Domain, C.

    2018-03-01

    The energetics, defect volume and magnetic properties of single SIAs and small SIA clusters up to size 6 have been calculated by DFT for different configurations like the parallel 〈110〉 dumbbell, the non parallel 〈110〉 dumbbell and the C15 structure. The most stable configurations of each type have been further analyzed to determine the influence on their stability of various solute atoms (Ti, V, Cr, Mn, Co, Ni, Cu, Mo, W, Pd, Al, Si, P), relevant for steels used under irradiation. The results show that the presence of solute atoms does not change the relative stability order among SIA clusters. The small SIA clusters investigated can bind to both undersized and oversized solutes. Several descriptors have been considered to derive interesting trends from results. It appears that the local atomic volume available for the solute is the main physical quantity governing the binding energy evolution, whatever the solute type (undersized or oversized) and the cluster configuration (size and type).

  17. Cerebral Small Vessel Disease: Cognition, Mood, Daily Functioning, and Imaging Findings from a Small Pilot Sample

    Directory of Open Access Journals (Sweden)

    John G. Baker

    2012-04-01

    Full Text Available Cerebral small vessel disease, a leading cause of cognitive decline, is considered a relatively homogeneous disease process, and it can co-occur with Alzheimer’s disease. Clinical reports of magnetic resonance imaging (MRI/computed tomography and single photon emission computed tomography (SPECT imaging and neuropsychology testing for a small pilot sample of 14 patients are presented to illustrate disease characteristics through findings from structural and functional imaging and cognitive assessment. Participants showed some decreases in executive functioning, attention, processing speed, and memory retrieval, consistent with previous literature. An older subgroup showed lower age-corrected scores at a single time point compared to younger participants. Performance on a computer-administered cognitive measure showed a slight overall decline over a period of 8–28 months. For a case study with mild neuropsychology findings, the MRI report was normal while the SPECT report identified perfusion abnormalities. Future research can test whether advances in imaging analysis allow for identification of cerebral small vessel disease before changes are detected in cognition.

  18. Dynamic Conformations of Nucleosome Arrays in Solution from Small-Angle X-ray Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Howell, Steven C. [George Washington Univ., Washington, DC (United States)

    2016-01-31

    We set out to determine quantitative information regarding the dynamic conformation of nucleosome arrays in solution using experimental SAXS. Toward this end, we developed a CG simulation algorithm for dsDNA which rapidly generates ensembles of structures through Metropolis MC sampling of a Markov chain.

  19. Nanopteron solutions of diatomic Fermi-Pasta-Ulam-Tsingou lattices with small mass-ratio

    Science.gov (United States)

    Hoffman, Aaron; Wright, J. Douglas

    2017-11-01

    Consider an infinite chain of masses, each connected to its nearest neighbors by a (nonlinear) spring. This is a Fermi-Pasta-Ulam-Tsingou lattice. We prove the existence of traveling waves in the setting where the masses alternate in size. In particular we address the limit where the mass ratio tends to zero. The problem is inherently singular and we find that the traveling waves are not true solitary waves but rather ;nanopterons;, which is to say, waves which are asymptotic at spatial infinity to very small amplitude periodic waves. Moreover, we can only find solutions when the mass ratio lies in a certain open set. The difficulties in the problem all revolve around understanding Jost solutions of a nonlocal Schrödinger operator in its semi-classical limit.

  20. Properties of solutions in semi-hyperbolic patches for unsteady transonic small disturbance equations

    Directory of Open Access Journals (Sweden)

    Ilija Jegdic

    2015-09-01

    Full Text Available We consider a two-dimensional Riemann problem for the unsteady transonic small disturbance equation resulting in diverging rarefaction waves. We write the problem in self-similar coordinates and we obtain a mixed type (hyperbolic-elliptic system. Resolving the one-dimensional discontinuities in the far field, where the system is hyperbolic, and using characteristics, we formulate the problem in a semi-hyperbolic patch that is between the hyperbolic and the elliptic regions. A semi-hyperbolic patch is known as a region where one family out of two nonlinear families of characteristics starts on a sonic curve and ends on a transonic shock. We obtain existence of a smooth local solution in this semi-hyperbolic patch and we prove various properties of global smooth solutions based on a characteristic decomposition using directional derivatives.

  1. Quantum superposition of the state discrete spectrum of mathematical correlation molecule for small samples of biometric data

    Directory of Open Access Journals (Sweden)

    Vladimir I. Volchikhin

    2017-06-01

    Full Text Available Introduction: The study promotes to decrease a number of errors of calculating the correlation coefficient in small test samples. Materials and Methods: We used simulation tool for the distribution functions of the density values of the correlation coefficient in small samples. A method for quantization of the data, allows obtaining a discrete spectrum states of one of the varieties of correlation functional. This allows us to consider the proposed structure as a mathematical correlation molecule, described by some analogue continuous-quantum Schrödinger equation. Results: The chi-squared Pearson’s molecule on small samples allows enhancing power of classical chi-squared test to 20 times. A mathematical correlation molecule described in the article has similar properties. It allows in the future reducing calculation errors of the classical correlation coefficients in small samples. Discussion and Conclusions: The authors suggest that there are infinitely many mathematical molecules are similar in their properties to the actual physical molecules. Schrödinger equations are not unique, their analogues can be constructed for each mathematical molecule. You can expect a mathematical synthesis of molecules for a large number of known statistical tests and statistical moments. All this should make it possible to reduce calculation errors due to quantum effects that occur in small test samples.

  2. Addressing small sample size bias in multiple-biomarker trials: Inclusion of biomarker-negative patients and Firth correction.

    Science.gov (United States)

    Habermehl, Christina; Benner, Axel; Kopp-Schneider, Annette

    2018-03-01

    In recent years, numerous approaches for biomarker-based clinical trials have been developed. One of these developments are multiple-biomarker trials, which aim to investigate multiple biomarkers simultaneously in independent subtrials. For low-prevalence biomarkers, small sample sizes within the subtrials have to be expected, as well as many biomarker-negative patients at the screening stage. The small sample sizes may make it unfeasible to analyze the subtrials individually. This imposes the need to develop new approaches for the analysis of such trials. With an expected large group of biomarker-negative patients, it seems reasonable to explore options to benefit from including them in such trials. We consider advantages and disadvantages of the inclusion of biomarker-negative patients in a multiple-biomarker trial with a survival endpoint. We discuss design options that include biomarker-negative patients in the study and address the issue of small sample size bias in such trials. We carry out a simulation study for a design where biomarker-negative patients are kept in the study and are treated with standard of care. We compare three different analysis approaches based on the Cox model to examine if the inclusion of biomarker-negative patients can provide a benefit with respect to bias and variance of the treatment effect estimates. We apply the Firth correction to reduce the small sample size bias. The results of the simulation study suggest that for small sample situations, the Firth correction should be applied to adjust for the small sample size bias. Additional to the Firth penalty, the inclusion of biomarker-negative patients in the analysis can lead to further but small improvements in bias and standard deviation of the estimates. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Sorption of molybdenum by cellulose polyphosphate from acid solutions

    International Nuclear Information System (INIS)

    Luneva, N.K.; Oputina, A.G.; Ermolenko, I.N.

    1985-01-01

    The sorption of molybdenum on cellulose polyphosphate from acid solutions of ammonium molybdate depending on the phosphorus content in samples, concentration and pH of the solution, sorption time is studied. It is shown that a maximum molybdenum content on the cellulose samples with different phosphorus content is pointed out at an ammonium molybdate concentration 0.02 M. Saturation of the sorption curve is attained at molar ratio of adsrbed molybdenum to phosphorus 1:4. In case of small fillings the compound with molybdenum to phosphorus ratio 1:10 is formed

  4. The Core Flight System (cFS) Community: Providing Low Cost Solutions for Small Spacecraft

    Science.gov (United States)

    McComas, David; Wilmot, Jonathan; Cudmore, Alan

    2016-01-01

    In February 2015 the NASA Goddard Space Flight Center (GSFC) completed the open source release of the entire Core Flight Software (cFS) suite. After the open source release a multi-NASA center Configuration Control Board (CCB) was established that has managed multiple cFS product releases. The cFS was developed and is being maintained in compliance with the NASA Class B software development process requirements and the open source release includes all Class B artifacts. The cFS is currently running on three operational science spacecraft and is being used on multiple spacecraft and instrument development efforts. While the cFS itself is a viable flight software (FSW) solution, we have discovered that the cFS community is a continuous source of innovation and growth that provides products and tools that serve the entire FSW lifecycle and future mission needs. This paper summarizes the current state of the cFS community, the key FSW technologies being pursued, the development/verification tools and opportunities for the small satellite community to become engaged. The cFS is a proven high quality and cost-effective solution for small satellites with constrained budgets.

  5. Bayesian estimation of the hydraulic and solute transport properties of a small-scale unsaturated soil column

    NARCIS (Netherlands)

    Moreira, Paulo H S; Van Genuchten, Martinus Th; Orlande, Helcio R B; Cotta, Renato M.

    2016-01-01

    In this study the hydraulic and solute transport properties of an unsaturated soil were estimated simultaneously from a relatively simple small-scale laboratory column infiltration/outflow experiment. As governing equations we used the Richards equation for variably saturated flow and a physical

  6. Solutions of simple dual bootstrap models satisfying Lee--Veneziano relation and the smallness of cut discontinuities

    International Nuclear Information System (INIS)

    Chiu, C.B.; Hossain, M.; Tow, D.M.

    1977-07-01

    To investigate the t-dependent solutions of simple dual bootstrap models, two general formulations are discussed, one without and one with cut cancellation at the planar level. The possible corresponding production mechanisms are discussed. In contrast to Bishari's formulation, both models recover the Lee-Veneziano relation, i.e., in the peak approximation the Pomeron intercept is unity. The solutions based on an exponential form for the reduced triple-Reggeon vertex for both models are discussed in detail. Also calculated are the cut discontinuities for both models and for Bishari's and it is shown that at both the planar and cylinder levels they are small compared with the corresponding pole residues. Precocious asymptotic planarity is also found in the solutions

  7. Evaluating mobile solutions of integrated Community Case ...

    African Journals Online (AJOL)

    evaluating mobile solutions of iCCM is of mixed quality. (e.g. few explanatory and confirmatory experimental studies, small sample sizes and observation periods, lack of a control). This casts into question the robustness of the evidence. Some shortcomings may be attributed to methodological choices during study design.

  8. Determination of the thermodynamic state of concentrated hemoglobin solutions by means of small angle X-ray scattering

    International Nuclear Information System (INIS)

    Zinke, M.

    1979-01-01

    Exemplified by hemoglobin, the thermodynamic equilibrium properties of the dissolved macromolecular system could be determined solely from the small angle X-ray scattering of concentrated macromolecular solutions via the intermolecular structure of the dissolved macromolecules and their intermolecular potentials. From the scattering experiment on concentrated Hb solutions the concentration dependence of the following properties of the dissolved Hb system were determined: fluctuation, isothermic compressibility, internal energy, surface tension, and osmotic pressure. (author)

  9. Continuous Passive Sampling of Solutes from Agricultural Subsurface Drainage Tubes

    Science.gov (United States)

    Lindblad Vendelboe, Anders; de Jonge, Hubert; Rozemeijer, Joachim; Wollesen de Jonge, Lis

    2015-04-01

    Agricultural subsurface tube drain systems play an important role in water and solute transport. One study, focusing on lowland agricultural catchments, showed that subsurface tube drainage contributed up to 80% of the annual discharge and 90% of the annual NO3 load from agricultural fields to the receiving water bodies. Knowledge of e.g. nutrient loads and drainage volumes, based on measurements and modelling, are important for adequate water quality management. Despite the importance of tube drain transport of solutes, monitoring data are scarce. This scarcity is a result of the existing monitoring techniques for flow and contaminant load from tube drains being expensive and labor-extensive. The study presented here aimed at developing a cheap, simple, and robust method to monitor solute loads from tube drains. The method is based on the newly developed Flowcap, which can be attached to existing tube drain outlets and can measure total flow, contaminant load and flow-averaged concentrations of solutes in the drainage. The Flowcap builds on the existing Sorbicell principle, a passive sampling system that measures average concentrations over longer periods of time (days to months) for various compounds. The Sorbicell consists of two compartments permeable to water. One compartment contains an adsorbent and one contains a tracer. When water passes through the Sorbicell the compound of interest is absorbed while a tracer is released. Using the tracer loss to calculate the volume of water that has passed the Sorbicell it is possible to calculate the average concentration of the compound. When mounting Sorbicells in the Flowcap, a flow-proportional part of the drainage is sampled from the main stream. To accommodate the wide range of drainage flow rates two Flowcaps with different capacities were tested in the laboratory: one with a capacity of 25 L min-1 (Q25) and one with a capacity of 256 L min-1 (Q256). In addition, Sorbicells with two different hydraulic

  10. Generic Learning-Based Ensemble Framework for Small Sample Size Face Recognition in Multi-Camera Networks.

    Science.gov (United States)

    Zhang, Cuicui; Liang, Xuefeng; Matsuyama, Takashi

    2014-12-08

    Multi-camera networks have gained great interest in video-based surveillance systems for security monitoring, access control, etc. Person re-identification is an essential and challenging task in multi-camera networks, which aims to determine if a given individual has already appeared over the camera network. Individual recognition often uses faces as a trial and requires a large number of samples during the training phrase. This is difficult to fulfill due to the limitation of the camera hardware system and the unconstrained image capturing conditions. Conventional face recognition algorithms often encounter the "small sample size" (SSS) problem arising from the small number of training samples compared to the high dimensionality of the sample space. To overcome this problem, interest in the combination of multiple base classifiers has sparked research efforts in ensemble methods. However, existing ensemble methods still open two questions: (1) how to define diverse base classifiers from the small data; (2) how to avoid the diversity/accuracy dilemma occurring during ensemble. To address these problems, this paper proposes a novel generic learning-based ensemble framework, which augments the small data by generating new samples based on a generic distribution and introduces a tailored 0-1 knapsack algorithm to alleviate the diversity/accuracy dilemma. More diverse base classifiers can be generated from the expanded face space, and more appropriate base classifiers are selected for ensemble. Extensive experimental results on four benchmarks demonstrate the higher ability of our system to cope with the SSS problem compared to the state-of-the-art system.

  11. Generic Learning-Based Ensemble Framework for Small Sample Size Face Recognition in Multi-Camera Networks

    Directory of Open Access Journals (Sweden)

    Cuicui Zhang

    2014-12-01

    Full Text Available Multi-camera networks have gained great interest in video-based surveillance systems for security monitoring, access control, etc. Person re-identification is an essential and challenging task in multi-camera networks, which aims to determine if a given individual has already appeared over the camera network. Individual recognition often uses faces as a trial and requires a large number of samples during the training phrase. This is difficult to fulfill due to the limitation of the camera hardware system and the unconstrained image capturing conditions. Conventional face recognition algorithms often encounter the “small sample size” (SSS problem arising from the small number of training samples compared to the high dimensionality of the sample space. To overcome this problem, interest in the combination of multiple base classifiers has sparked research efforts in ensemble methods. However, existing ensemble methods still open two questions: (1 how to define diverse base classifiers from the small data; (2 how to avoid the diversity/accuracy dilemma occurring during ensemble. To address these problems, this paper proposes a novel generic learning-based ensemble framework, which augments the small data by generating new samples based on a generic distribution and introduces a tailored 0–1 knapsack algorithm to alleviate the diversity/accuracy dilemma. More diverse base classifiers can be generated from the expanded face space, and more appropriate base classifiers are selected for ensemble. Extensive experimental results on four benchmarks demonstrate the higher ability of our system to cope with the SSS problem compared to the state-of-the-art system.

  12. Small angle neutron scattering study of the gemini nonionic surfactant in heavy water solutions

    International Nuclear Information System (INIS)

    Rajewska, A

    2012-01-01

    The nonionic gemini surfactant α α'-[2,4,7,9-tetramethyl-5-decyne-4,7diyl]bis[ω hydroxyl-polyoxyethylene] (S-10) was investigated in heavy water solutions only for concentrations: 2.3%, 2.5%,3%, 3.4%, 4% and 5% at temperature 25 C with small angle neutron scattering (SANS) method. All of surfactants solutions were prepared using D 2 O (99.9% deuterated, Prikladnaia Chimia, St. Petersburg, Russia) as a solvent. The nonionic gemini surfactant S-10 was obtained from Air Products and Chemicals, Inc., and used without further purification. All SANS measurements were performed on V-4 SANS spectrometer at BENSC, Berlin (Germany). Neutrons were used in wavelength range of 0.02 - 4 nm - 1. For the measurements quartz cells of were used during experiment. Up to 14 such cells were placed in a holder. Results from experiment was calculated and evaluated with PCG 2.0 program from Graz University (Austria). In the investigated solutions two axis ellipsoidal micelles was observed.

  13. Rural and small-town attitudes about alcohol use during pregnancy: a community and provider sample.

    Science.gov (United States)

    Logan, T K; Walker, Robert; Nagle, Laura; Lewis, Jimmie; Wiesenhahn, Donna

    2003-01-01

    While there has been considerable research on prenatal alcohol use, there have been limited studies focused on women in rural and small-town environments. This 2-part study examines gender differences in attitudes and perceived barriers to intervention in large community sample of persons living in rural and small-town environments in Kentucky (n = 3,346). The study also examines rural/small-town prenatal service providers' perceptions of barriers to assessment and intervention with pregnant substance abusers (n = 138). Surveys were administered to a convenience sample of employees and customers from 16 rural and small-town community outlets. There were 1503 males (45%) and 1843 females (55%) ranging in age from under 18 years old to over 66 years old. Surveys also were mailed to prenatal providers in county health departments of the 13-county study area, with 138 of 149 responding. Overall results of the community sample suggest that neither males nor females were knowledgeable about the harmful effects of alcohol use during pregnancy. Results also indicate substantial gender differences in alcohol attitudes, knowledge, and perceived barriers. Further, prenatal care providers identified several barriers in assessment and treatment of pregnant women with alcohol use problems in rural and small-town communities, including lack of knowledge and comfort with assessment as well as a lack of available and accessible treatment for referrals.

  14. Assessment of reagent effectiveness and preservation methods for equine faecal samples

    Directory of Open Access Journals (Sweden)

    Eva Vavrouchova

    2015-03-01

    Full Text Available The aim of our study was to identify the most suitable flotation solution and effective preservation method for the examination of equine faeces samples using the FLOTAC technique. Samples from naturally infected horses were transported to the laboratory andanalysed accordingly. The sample from each horse was homogenized and divided into four parts: one was frozen, another two were preserved in different reagents such as sodium acetate-acetic-acid–formalin (SAF or 5% formalin.The last part was examined as a fresh sample in three different flotation solutions (Sheather´s solution, sodium chloride and sodium nitrate solution, all with a specific gravity 1.200. The preserved samples were examined in the period from 14 to21days after collection. According to our results, the sucrose solution was the most suitable flotation solution for fresh samples (small strongyle egg per gram was 706 compared to 360 in sodium chlorid and 507 in sodium nitrate and the sodium nitrate solution was the most efficient for the preserved samples (egg per gram was 382 compared to 295 in salt solution and 305 in sucrose solution. Freezing appears to be the most effective method of sample preservation, resulting in minimal damage to fragile strongyle eggs and therefore it is the most simple and effective preservation method for the examination of large numbers of faecal samples without the necessity of examining them all within 48 hours of collection. Deep freezing as a preservation method for equine faeces samples has not, according to our knowledge, been yet published.

  15. Method for Measuring Thermal Conductivity of Small Samples Having Very Low Thermal Conductivity

    Science.gov (United States)

    Miller, Robert A.; Kuczmarski, Maria a.

    2009-01-01

    This paper describes the development of a hot plate method capable of using air as a standard reference material for the steady-state measurement of the thermal conductivity of very small test samples having thermal conductivity on the order of air. As with other approaches, care is taken to ensure that the heat flow through the test sample is essentially one-dimensional. However, unlike other approaches, no attempt is made to use heated guards to block the flow of heat from the hot plate to the surroundings. It is argued that since large correction factors must be applied to account for guard imperfections when sample dimensions are small, it may be preferable to simply measure and correct for the heat that flows from the heater disc to directions other than into the sample. Experimental measurements taken in a prototype apparatus, combined with extensive computational modeling of the heat transfer in the apparatus, show that sufficiently accurate measurements can be obtained to allow determination of the thermal conductivity of low thermal conductivity materials. Suggestions are made for further improvements in the method based on results from regression analyses of the generated data.

  16. Analysis of small sample size studies using nonparametric bootstrap test with pooled resampling method.

    Science.gov (United States)

    Dwivedi, Alok Kumar; Mallawaarachchi, Indika; Alvarado, Luis A

    2017-06-30

    Experimental studies in biomedical research frequently pose analytical problems related to small sample size. In such studies, there are conflicting findings regarding the choice of parametric and nonparametric analysis, especially with non-normal data. In such instances, some methodologists questioned the validity of parametric tests and suggested nonparametric tests. In contrast, other methodologists found nonparametric tests to be too conservative and less powerful and thus preferred using parametric tests. Some researchers have recommended using a bootstrap test; however, this method also has small sample size limitation. We used a pooled method in nonparametric bootstrap test that may overcome the problem related with small samples in hypothesis testing. The present study compared nonparametric bootstrap test with pooled resampling method corresponding to parametric, nonparametric, and permutation tests through extensive simulations under various conditions and using real data examples. The nonparametric pooled bootstrap t-test provided equal or greater power for comparing two means as compared with unpaired t-test, Welch t-test, Wilcoxon rank sum test, and permutation test while maintaining type I error probability for any conditions except for Cauchy and extreme variable lognormal distributions. In such cases, we suggest using an exact Wilcoxon rank sum test. Nonparametric bootstrap paired t-test also provided better performance than other alternatives. Nonparametric bootstrap test provided benefit over exact Kruskal-Wallis test. We suggest using nonparametric bootstrap test with pooled resampling method for comparing paired or unpaired means and for validating the one way analysis of variance test results for non-normal data in small sample size studies. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  17. A-π-D-π-A Electron-Donating Small Molecules for Solution-Processed Organic Solar Cells: A Review.

    Science.gov (United States)

    Wang, Zhen; Zhu, Lingyun; Shuai, Zhigang; Wei, Zhixiang

    2017-11-01

    Organic solar cells based on semiconducting polymers and small molecules have attracted considerable attention in the last two decades. Moreover, the power conversion efficiencies for solution-processed solar cells containing A-π-D-π-A-type small molecules and fullerenes have reached 11%. However, the method for designing high-performance, photovoltaic small molecules still remains unclear. In this review, recent studies on A-π-D-π-A electron-donating small molecules for organic solar cells are introduced. Moreover, the relationships between molecular properties and device performances are summarized, from which inspiration for the future design of high performance organic solar cells may be obtained. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Structure of polyacrylic acid and polymethacrylic acid solutions : a small angle neutron scattering study

    OpenAIRE

    Moussaid , A.; Schosseler , F.; Munch , J.; Candau , S.

    1993-01-01

    The intensity scattered from polyacrylic acid and polymethacrylic acid solutions has been measured by small angle neutron scattering experiemnts. The influence of polymer concentration, ionization degree, temperature and salt content has been investigated. Results are in qualitative agreement with a model which predicts the existence of microphases in the unstable region of the phase diagram. Quantitative comparison with the theory is performed by fitting the theoretical structure factor to t...

  19. A technique of evaluating most probable stochastic valuables from a small number of samples and their accuracies and degrees of confidence

    Energy Technology Data Exchange (ETDEWEB)

    Katoh, K [Ibaraki Pref. Univ. Health Sci., (Japan)

    1997-12-31

    A problem of estimating stochastic characteristics of a population from a small number of samples is solved as an inverse problem, from view point of information theory and with the Bayesian statistics. For both Poisson-process and Bernoulli-process, the most probable values of the characteristics of the mother population and their accuracies and degrees of confidence are successfully obtained. Mathematical expressions are given to the general case where a limit amount of information and/or knowledge with the stochastic characteristics are available and a special case where no a priori information nor knowledge are available. Mathematical properties of the solutions obtained, practical appreciation to the problem to radiation measurement are also discussed.

  20. Small Sample Properties of the Wilcoxon Signed Rank Test with Discontinuous and Dependent Observations

    OpenAIRE

    Nadine Chlass; Jens J. Krueger

    2007-01-01

    This Monte-Carlo study investigates sensitivity of the Wilcoxon signed rank test to certain assumption violations in small samples. Emphasis is put on within-sample-dependence, between-sample dependence, and the presence of ties. Our results show that both assumption violations induce severe size distortions and entail power losses. Surprisingly, these consequences do vary substantially with other properties the data may display. Results provided are particularly relevant for experimental set...

  1. Investigation of microwave assisted drying of samples and evaporation of aqueous solutions in trace element analysis

    Energy Technology Data Exchange (ETDEWEB)

    Maichin, B.; Knapp, G. [Technische Univ., Graz (Austria). Inst. fuer Analytische Chemie, Mikro- und Radiochemie; Kettisch, P. [Anton Paar GmbH, Graz (Austria)

    2000-01-01

    Investigations of microwave assisted drying of sample materials and microwave assisted evaporation of aqueous sample solutions and acidic digestion residues were accomplished by means of special rotors for the microwave digestion system MULTIWAVE. To check the results obtained by microwave assisted drying, the samples were also conventionally dried at 105 C in an oven. The following samples have been dried: 10 g each of meat, fish, apple, cucumber, potato, mustard, yogurt, clay and marl; 1 g each of certified reference material TORT 2 (lobster hepatopancreas), BCR 278 (mussel tissue) and BCR 422 (cod muscle); 500 g garden mould. Microwave assisted drying takes 40 min for organic samples and 30 min for inorganic material. Important is a slow increase of microwave power during the first 20 min. The results agree well with conventional drying at 105 C. Losses of As, Se and Hg have been investigated for 3 CRMs. Only Se shows losses in the range of 20%. Losses of As, Be, Cd, Co, Cr, Cu, Fe, Hg, Li, Mg, Mn, Mo, Ni, Pb, Sb, Se, Sr, Ti, Tl, V and Zn after evaporation of aqueous samples and acidic solutions after wet digestion, respectively, have been investigated. 50 mL aqueous solution was evaporated almost to dryness within 25 min. The recovery of Hg is 40-50%, of Se 90-95% and of the other elements 97-102%. 0.2 g each of TORT 2, BCR 278 and BCR 422 have been digested with 4 mL nitric acid and 1 mL hydrochloric acid by means of the microwave digestion system MULTIWAVE. The digestion residue was evaporated almost to dryness and dissolved again in 10 mL diluted nitric acid. In this case no element losses have been observed. The measured concentration of As, Cd, Cu, Fe, Mn, Hg, Pb, Mo, Ni, Se, Sr, V and Zn agree very well with the certified values. An important prerequisite for good recoveries is not to evaporate the solutions to complete dryness. (orig.)

  2. Small-angle x-ray scattering investigation of the solution structure of troponin C

    International Nuclear Information System (INIS)

    Hubbard, S.R.; Hodgson, K.O.; Doniach, S.

    1988-01-01

    X-ray crystallographic studies of troponin C have revealed a novel protein structure consisting of two globular domains, each containing two Ca 2+ -binding sites, connected via a nine-turn alpha-helix, three turns of which are fully exposed to solvent. Since the crystals were grown at pH approximately 5, it is of interest to determine whether this structure is applicable to the protein in solution under physiological conditions. We have used small-angle x-ray scattering to examine the solution structure of troponin C at pH 6.8 and the effect of Ca 2+ on the structure. The scattering data are consistent with an elongated structure in solution with a radius of gyration of approximately 23.0 A, which is quite comparable to that computed for the crystal structure. The experimental scattering profile and the scattering profile computed from the crystal structure coordinates do, however, exhibit differences at the 40-A level. A weak Ca 2+ -facilitated dimerization of troponin C was observed. The data rule out large Ca 2+ -induced structural changes, indicating rather that the molecule with Ca 2+ bound is only slightly more compact than the Ca 2+ -free molecule

  3. Sample-averaged biexciton quantum yield measured by solution-phase photon correlation.

    Science.gov (United States)

    Beyler, Andrew P; Bischof, Thomas S; Cui, Jian; Coropceanu, Igor; Harris, Daniel K; Bawendi, Moungi G

    2014-12-10

    The brightness of nanoscale optical materials such as semiconductor nanocrystals is currently limited in high excitation flux applications by inefficient multiexciton fluorescence. We have devised a solution-phase photon correlation measurement that can conveniently and reliably measure the average biexciton-to-exciton quantum yield ratio of an entire sample without user selection bias. This technique can be used to investigate the multiexciton recombination dynamics of a broad scope of synthetically underdeveloped materials, including those with low exciton quantum yields and poor fluorescence stability. Here, we have applied this method to measure weak biexciton fluorescence in samples of visible-emitting InP/ZnS and InAs/ZnS core/shell nanocrystals, and to demonstrate that a rapid CdS shell growth procedure can markedly increase the biexciton fluorescence of CdSe nanocrystals.

  4. Identification of multiple mRNA and DNA sequences from small tissue samples isolated by laser-assisted microdissection.

    Science.gov (United States)

    Bernsen, M R; Dijkman, H B; de Vries, E; Figdor, C G; Ruiter, D J; Adema, G J; van Muijen, G N

    1998-10-01

    Molecular analysis of small tissue samples has become increasingly important in biomedical studies. Using a laser dissection microscope and modified nucleic acid isolation protocols, we demonstrate that multiple mRNA as well as DNA sequences can be identified from a single-cell sample. In addition, we show that the specificity of procurement of tissue samples is not compromised by smear contamination resulting from scraping of the microtome knife during sectioning of lesions. The procedures described herein thus allow for efficient RT-PCR or PCR analysis of multiple nucleic acid sequences from small tissue samples obtained by laser-assisted microdissection.

  5. Gray bootstrap method for estimating frequency-varying random vibration signals with small samples

    Directory of Open Access Journals (Sweden)

    Wang Yanqing

    2014-04-01

    Full Text Available During environment testing, the estimation of random vibration signals (RVS is an important technique for the airborne platform safety and reliability. However, the available methods including extreme value envelope method (EVEM, statistical tolerances method (STM and improved statistical tolerance method (ISTM require large samples and typical probability distribution. Moreover, the frequency-varying characteristic of RVS is usually not taken into account. Gray bootstrap method (GBM is proposed to solve the problem of estimating frequency-varying RVS with small samples. Firstly, the estimated indexes are obtained including the estimated interval, the estimated uncertainty, the estimated value, the estimated error and estimated reliability. In addition, GBM is applied to estimating the single flight testing of certain aircraft. At last, in order to evaluate the estimated performance, GBM is compared with bootstrap method (BM and gray method (GM in testing analysis. The result shows that GBM has superiority for estimating dynamic signals with small samples and estimated reliability is proved to be 100% at the given confidence level.

  6. Basic distribution free identification tests for small size samples of environmental data

    International Nuclear Information System (INIS)

    Federico, A.G.; Musmeci, F.

    1998-01-01

    Testing two or more data sets for the hypothesis that they are sampled form the same population is often required in environmental data analysis. Typically the available samples have a small number of data and often then assumption of normal distributions is not realistic. On the other hand the diffusion of the days powerful Personal Computers opens new possible opportunities based on a massive use of the CPU resources. The paper reviews the problem introducing the feasibility of two non parametric approaches based on intrinsic equi probability properties of the data samples. The first one is based on a full re sampling while the second is based on a bootstrap approach. A easy to use program is presented. A case study is given based on the Chernobyl children contamination data [it

  7. Bayesian estimation of the hydraulic and solute transport properties of a small-scale unsaturated soil column

    Directory of Open Access Journals (Sweden)

    Moreira Paulo H. S.

    2016-03-01

    Full Text Available In this study the hydraulic and solute transport properties of an unsaturated soil were estimated simultaneously from a relatively simple small-scale laboratory column infiltration/outflow experiment. As governing equations we used the Richards equation for variably saturated flow and a physical non-equilibrium dual-porosity type formulation for solute transport. A Bayesian parameter estimation approach was used in which the unknown parameters were estimated with the Markov Chain Monte Carlo (MCMC method through implementation of the Metropolis-Hastings algorithm. Sensitivity coefficients were examined in order to determine the most meaningful measurements for identifying the unknown hydraulic and transport parameters. Results obtained using the measured pressure head and solute concentration data collected during the unsaturated soil column experiment revealed the robustness of the proposed approach.

  8. High performance photovoltaic applications using solution-processed small molecules.

    Science.gov (United States)

    Chen, Yongsheng; Wan, Xiangjian; Long, Guankui

    2013-11-19

    Energy remains a critical issue for the survival and prosperity of humancivilization. Many experts believe that the eventual solution for sustainable energy is the use of direct solar energy as the main energy source. Among the options for renewable energy, photovoltaic technologies that harness solar energy offer a way to harness an unlimited resource and minimum environment impact in contrast with other alternatives such as water, nuclear, and wind energy. Currently, almost all commercial photovoltaic technologies use Si-based technology, which has a number of disadvantages including high cost, lack of flexibility, and the serious environmental impact of the Si industry. Other technologies, such as organic photovoltaic (OPV) cells, can overcome some of these issues. Today, polymer-based OPV (P-OPV) devices have achieved power conversion efficiencies (PCEs) that exceed 9%. Compared with P-OPV, small molecules based OPV (SM-OPV) offers further advantages, including a defined structure for more reproducible performance, higher mobility and open circuit voltage, and easier synthetic control that leads to more diversified structures. Therefore, while largely undeveloped, SM-OPV is an important emerging technology with performance comparable to P-OPV. In this Account, we summarize our recent results on solution-processed SM-OPV. We believe that solution processing is essential for taking full advantage of OPV technologies. Our work started with the synthesis of oligothiophene derivatives with an acceptor-donor-acceptor (A-D-A) structure. Both the backbone conjugation length and electron withdrawing terminal groups play an important role in the light absorption, energy levels and performance of the devices. Among those molecules, devices using a 7-thiophene-unit backbone and a 3-ethylrhodanine (RD) terminal unit produced a 6.1% PCE. With the optimized conjugation length and terminal unit, we borrowed from the results with P-OPV devices to optimize the backbone. Thus we

  9. Microsoft Access Small Business Solutions State-of-the-Art Database Models for Sales, Marketing, Customer Management, and More Key Business Activities

    CERN Document Server

    Hennig, Teresa; Linson, Larry; Purvis, Leigh; Spaulding, Brent

    2010-01-01

    Database models developed by a team of leading Microsoft Access MVPs that provide ready-to-use solutions for sales, marketing, customer management and other key business activities for most small businesses. As the most popular relational database in the world, Microsoft Access is widely used by small business owners. This book responds to the growing need for resources that help business managers and end users design and build effective Access database solutions for specific business functions. Coverage includes::; Elements of a Microsoft Access Database; Relational Data Model; Dealing with C

  10. Oxalic acid as a liquid dosimeter for absorbed dose measurement in large-scale of sample solution

    International Nuclear Information System (INIS)

    Biramontri, S.; Dechburam, S.; Vitittheeranon, A.; Wanitsuksombut, W.; Thongmitr, W.

    1999-01-01

    This study shows the feasibility for, applying 2.5 mM aqueous oxalic acid solution using spectrophotometric analysis method for absorbed dose measurement from 1 to 10 kGy in a large-scale of sample solution. The optimum wavelength of 220 nm was selected. The stability of the response of the dosimeter over 25 days was better than 1 % for unirradiated and ± 2% for irradiated solution. The reproducibility in the same batch was within 1%. The variation of the dosimeter response between batches was also studied. (author)

  11. Replica exchange with solute tempering: A method for sampling biological systems in explicit water

    Science.gov (United States)

    Liu, Pu; Kim, Byungchan; Friesner, Richard A.; Berne, B. J.

    2005-09-01

    An innovative replica exchange (parallel tempering) method called replica exchange with solute tempering (REST) for the efficient sampling of aqueous protein solutions is presented here. The method bypasses the poor scaling with system size of standard replica exchange and thus reduces the number of replicas (parallel processes) that must be used. This reduction is accomplished by deforming the Hamiltonian function for each replica in such a way that the acceptance probability for the exchange of replica configurations does not depend on the number of explicit water molecules in the system. For proof of concept, REST is compared with standard replica exchange for an alanine dipeptide molecule in water. The comparisons confirm that REST greatly reduces the number of CPUs required by regular replica exchange and increases the sampling efficiency. This method reduces the CPU time required for calculating thermodynamic averages and for the ab initio folding of proteins in explicit water. Author contributions: B.J.B. designed research; P.L. and B.K. performed research; P.L. and B.K. analyzed data; and P.L., B.K., R.A.F., and B.J.B. wrote the paper.Abbreviations: REST, replica exchange with solute tempering; REM, replica exchange method; MD, molecular dynamics.*P.L. and B.K. contributed equally to this work.

  12. Mixing of Process Heels, Process Solutions and Recycle Streams: Small-Scale Simulant

    International Nuclear Information System (INIS)

    Kaplan, D.I.

    2001-01-01

    The overall objective of this small-scale simulant mixing study was to identify the processes within the Hanford Site River Protection Project - Waste Treatment Plant (RPP-WTP) that may generate precipitates and to identify the types of precipitates formed. This information can be used to identify where mixtures of various solutions will cause precipitation of solids, potentially causing operational problems such as fouling equipment or increasing the amount of High Level Waste glass produced. Having this information will help guide protocols for flushing or draining tanks, mixing internal recycle streams, and mixing waste tank supernates. This report contains the discussion and thermodynamic chemical speciation modeling of the raw data

  13. Decoder calibration with ultra small current sample set for intracortical brain-machine interface

    Science.gov (United States)

    Zhang, Peng; Ma, Xuan; Chen, Luyao; Zhou, Jin; Wang, Changyong; Li, Wei; He, Jiping

    2018-04-01

    Objective. Intracortical brain-machine interfaces (iBMIs) aim to restore efficient communication and movement ability for paralyzed patients. However, frequent recalibration is required for consistency and reliability, and every recalibration will require relatively large most current sample set. The aim in this study is to develop an effective decoder calibration method that can achieve good performance while minimizing recalibration time. Approach. Two rhesus macaques implanted with intracortical microelectrode arrays were trained separately on movement and sensory paradigm. Neural signals were recorded to decode reaching positions or grasping postures. A novel principal component analysis-based domain adaptation (PDA) method was proposed to recalibrate the decoder with only ultra small current sample set by taking advantage of large historical data, and the decoding performance was compared with other three calibration methods for evaluation. Main results. The PDA method closed the gap between historical and current data effectively, and made it possible to take advantage of large historical data for decoder recalibration in current data decoding. Using only ultra small current sample set (five trials of each category), the decoder calibrated using the PDA method could achieve much better and more robust performance in all sessions than using other three calibration methods in both monkeys. Significance. (1) By this study, transfer learning theory was brought into iBMIs decoder calibration for the first time. (2) Different from most transfer learning studies, the target data in this study were ultra small sample set and were transferred to the source data. (3) By taking advantage of historical data, the PDA method was demonstrated to be effective in reducing recalibration time for both movement paradigm and sensory paradigm, indicating a viable generalization. By reducing the demand for large current training data, this new method may facilitate the application

  14. Specific wavelength colorimeter. [for measuring given solute concentration in test sample

    Science.gov (United States)

    Brawner, C. C.; Mcdavid, L. S.; Walsh, J. M. (Inventor)

    1974-01-01

    A self contained, specific wavelength, single beam colorimeter is described for direct spectrophotometric measurement of the concentration of a given solute in a test sample. An electrical circuit employing a photoconductive cell converts the optical output into a linear, directly readable meter output. The colorimeter is simple to operate and is adapted for use in zero gravity conditions. In a specific application, the colorimeter is designed to analyze the concentration of iodine in potable water carried aboard a space vehicle such as the 4B stage of Skylab.

  15. A simple high performance liquid chromatography method for analyzing paraquat in soil solution samples.

    Science.gov (United States)

    Ouyang, Ying; Mansell, Robert S; Nkedi-Kizza, Peter

    2004-01-01

    A high performance liquid chromatography (HPLC) method with UV detection was developed to analyze paraquat (1,1'-dimethyl-4,4'-dipyridinium dichloride) herbicide content in soil solution samples. The analytical method was compared with the liquid scintillation counting (LSC) method using 14C-paraquat. Agreement obtained between the two methods was reasonable. However, the detection limit for paraquat analysis was 0.5 mg L(-1) by the HPLC method and 0.05 mg L(-1) by the LSC method. The LSC method was, therefore, 10 times more precise than the HPLC method for solution concentrations less than 1 mg L(-1). In spite of the high detection limit, the UC (nonradioactive) HPLC method provides an inexpensive and environmentally safe means for determining paraquat concentration in soil solution compared with the 14C-LSC method.

  16. Baysian estimation of P(X > x) from a small sample of Gaussian data

    DEFF Research Database (Denmark)

    Ditlevsen, Ove Dalager

    2017-01-01

    The classical statistical uncertainty problem of estimation of upper tail probabilities on the basis of a small sample of observations of a Gaussian random variable is considered. Predictive posterior estimation is discussed, adopting the standard statistical model with diffuse priors of the two...

  17. Taking sputum samples from small children with cystic fibrosis: a matter of cooperation

    DEFF Research Database (Denmark)

    Pehn, Mette; Bregnballe, Vibeke

    2014-01-01

    Objectives: An important part of the disease control in Danish guidelines for care of patients with cystic fibrosis (CF) is a monthly sputum sample by tracheal suchtion. Coping to this unpleasant procedure in small children depends heavily on the support from parents and nurse. The objective...... of this study was to develop a tool to help parents and children to cope with tracheal suctioning. Methods: Three short videos showing how nurses perform tracheal suctioning to get a sputum sample from small children with cystic fibrosis were made. The videos were shown to and discussed with parents...... and children to help them identify their own challenges in coping with the procedure. The study was carried out in the outpatient clinic at the CF centre, Aarhus Univeristy Hospital. Results: The videos are a useful tool to convince the parents, nurses and children from the age of about four years...

  18. On the use of the Lie group technique for differential equations with a small parameter: Approximate solutions and integrable equations

    International Nuclear Information System (INIS)

    Burde, G.I.

    2002-01-01

    A new approach to the use of the Lie group technique for partial and ordinary differential equations dependent on a small parameter is developed. In addition to determining approximate solutions to the perturbed equation, the approach allows constructing integrable equations that have solutions with (partially) prescribed features. Examples of application of the approach to partial differential equations are given

  19. The applications of small-angle X-ray scattering in studying nano-scaled polyoxometalate clusters in solutions

    Science.gov (United States)

    Li, Mu; Zhang, Mingxin; Wang, Weiyu; Cheng, Stephen Z. D.; Yin, Panchao

    2018-05-01

    Nano-scaled polyoxometalates (POMs) clusters with sizes ranging from 1 to 10 nm attract tremendous attention and have been extensively studied due to POMs' fascinating structural characteristics and prospects for wide-ranging applications. As a unique class of nanoparticles with well-defined structural topologies and monodispersed masses, the structures and properties of POMs in both bulk state and solutions have been explored with several well-developed protocols. Small-angle X-ray scattering (SAXS) technique, as a powerful tool for studying polymers and nanoparticles, has been recently extended to the investigating of solution behaviors of POMs. In this mini-review, the general principle and typical experimental procedures of SAXS are illustrated first. The applications of SAXS in characterizing POMs' morphology, counterion distribution around POMs, and short-range interactions among POMs in solutions are highlighted. [Figure not available: see fulltext.

  20. Small-vessel Survey and Auction Sampling to Estimate Growth and Maturity of Eteline Snappers

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Small-vessel Survey and Auction Sampling to Estimate Growth and Maturity of Eteline Snappers and Improve Data-Limited Stock Assessments. This biosampling project...

  1. Conditional estimation of local pooled dispersion parameter in small-sample RNA-Seq data improves differential expression test.

    Science.gov (United States)

    Gim, Jungsoo; Won, Sungho; Park, Taesung

    2016-10-01

    High throughput sequencing technology in transcriptomics studies contribute to the understanding of gene regulation mechanism and its cellular function, but also increases a need for accurate statistical methods to assess quantitative differences between experiments. Many methods have been developed to account for the specifics of count data: non-normality, a dependence of the variance on the mean, and small sample size. Among them, the small number of samples in typical experiments is still a challenge. Here we present a method for differential analysis of count data, using conditional estimation of local pooled dispersion parameters. A comprehensive evaluation of our proposed method in the aspect of differential gene expression analysis using both simulated and real data sets shows that the proposed method is more powerful than other existing methods while controlling the false discovery rates. By introducing conditional estimation of local pooled dispersion parameters, we successfully overcome the limitation of small power and enable a powerful quantitative analysis focused on differential expression test with the small number of samples.

  2. Study of particles in solution by small angle x-ray scattering

    International Nuclear Information System (INIS)

    Itri, R.

    1986-01-01

    The implantation of SAXS technique is presented, and mycellas in solution of the dodecyl sodium sulfate SLS/water system are studied. A synthesis of SAXS theory to study parameters such as, volume, radii of gyration and specific surface and distribution function of the distance of homogenous and inhomogeneous particles is also presented. The technique was implanted by the study of a vitreous coal sample with voids in amorphous matrix. Computer programs were used for data treatment. It was concluded that the void configuration must be an oblate ellipsoid with rippled external surface and radii of gyration of ∼20A . The study of mycellas in solution of the SLL/H 2 O binary system showed spherical mycellas with paraffinic radii of 16A and total radii of 25.5 A. Interaction effects start to appear in 15% SLS concentrations. The change in the scattering curve occurs due to the interactions between mycellas. The isotropic-nematic transition in the ternary system by decanol addition was also investigated. (M.C.K.) [pt

  3. Clustering Methods with Qualitative Data: a Mixed-Methods Approach for Prevention Research with Small Samples.

    Science.gov (United States)

    Henry, David; Dymnicki, Allison B; Mohatt, Nathaniel; Allen, James; Kelly, James G

    2015-10-01

    Qualitative methods potentially add depth to prevention research but can produce large amounts of complex data even with small samples. Studies conducted with culturally distinct samples often produce voluminous qualitative data but may lack sufficient sample sizes for sophisticated quantitative analysis. Currently lacking in mixed-methods research are methods allowing for more fully integrating qualitative and quantitative analysis techniques. Cluster analysis can be applied to coded qualitative data to clarify the findings of prevention studies by aiding efforts to reveal such things as the motives of participants for their actions and the reasons behind counterintuitive findings. By clustering groups of participants with similar profiles of codes in a quantitative analysis, cluster analysis can serve as a key component in mixed-methods research. This article reports two studies. In the first study, we conduct simulations to test the accuracy of cluster assignment using three different clustering methods with binary data as produced when coding qualitative interviews. Results indicated that hierarchical clustering, K-means clustering, and latent class analysis produced similar levels of accuracy with binary data and that the accuracy of these methods did not decrease with samples as small as 50. Whereas the first study explores the feasibility of using common clustering methods with binary data, the second study provides a "real-world" example using data from a qualitative study of community leadership connected with a drug abuse prevention project. We discuss the implications of this approach for conducting prevention research, especially with small samples and culturally distinct communities.

  4. Clustering Methods with Qualitative Data: A Mixed Methods Approach for Prevention Research with Small Samples

    Science.gov (United States)

    Henry, David; Dymnicki, Allison B.; Mohatt, Nathaniel; Allen, James; Kelly, James G.

    2016-01-01

    Qualitative methods potentially add depth to prevention research, but can produce large amounts of complex data even with small samples. Studies conducted with culturally distinct samples often produce voluminous qualitative data, but may lack sufficient sample sizes for sophisticated quantitative analysis. Currently lacking in mixed methods research are methods allowing for more fully integrating qualitative and quantitative analysis techniques. Cluster analysis can be applied to coded qualitative data to clarify the findings of prevention studies by aiding efforts to reveal such things as the motives of participants for their actions and the reasons behind counterintuitive findings. By clustering groups of participants with similar profiles of codes in a quantitative analysis, cluster analysis can serve as a key component in mixed methods research. This article reports two studies. In the first study, we conduct simulations to test the accuracy of cluster assignment using three different clustering methods with binary data as produced when coding qualitative interviews. Results indicated that hierarchical clustering, K-Means clustering, and latent class analysis produced similar levels of accuracy with binary data, and that the accuracy of these methods did not decrease with samples as small as 50. Whereas the first study explores the feasibility of using common clustering methods with binary data, the second study provides a “real-world” example using data from a qualitative study of community leadership connected with a drug abuse prevention project. We discuss the implications of this approach for conducting prevention research, especially with small samples and culturally distinct communities. PMID:25946969

  5. Interval estimation methods of the mean in small sample situation and the results' comparison

    International Nuclear Information System (INIS)

    Wu Changli; Guo Chunying; Jiang Meng; Lin Yuangen

    2009-01-01

    The methods of the sample mean's interval estimation, namely the classical method, the Bootstrap method, the Bayesian Bootstrap method, the Jackknife method and the spread method of the Empirical Characteristic distribution function are described. Numerical calculation on the samples' mean intervals is carried out where the numbers of the samples are 4, 5, 6 respectively. The results indicate the Bootstrap method and the Bayesian Bootstrap method are much more appropriate than others in small sample situation. (authors)

  6. Compact structure of ribosomal protein S4 in solution as revealed by small-angle X-ray scattering

    International Nuclear Information System (INIS)

    Serdyuk, I.N.; Sarkisyan, M.A.; Gogia, Z.V.

    1981-01-01

    The authors report the results of a small-angle X-ray scattering study of ribosomal protein preparations obtained by neutron scattering method. The theoretical resolution of the diffractometer (Kratky camera, the entrance slit 80 μm, the receiving slit 190 μm, the sample-detector distance 20.4 cm) was the same as the resolution of X-ray diffractometers, on which high rsub(g) values for ribosomal proteins were obtained. They used protein S4 adjusted to 20 mg/ml without any essential loss of solubility. The scattering indicatrix obtained in a wide range of angles has demonstrated that the X-ray rsub(g) obtained here coincides with the earlier obtained neutron rsub(g) and the outer part of the scattering curve is similar to that of slightly elongated compact bodies. They conclude that all discrepancies between their data on the study of ribosomal protein structure in solution and other data are not connected with the characteristics of the instruments used but only with the quality of the protein preparations. (Auth.)

  7. Proteins in solution: Fractal surfaces in solutions

    Directory of Open Access Journals (Sweden)

    R. Tscheliessnig

    2016-02-01

    Full Text Available The concept of the surface of a protein in solution, as well of the interface between protein and 'bulk solution', is introduced. The experimental technique of small angle X-ray and neutron scattering is introduced and described briefly. Molecular dynamics simulation, as an appropriate computational tool for studying the hydration shell of proteins, is also discussed. The concept of protein surfaces with fractal dimensions is elaborated. We finish by exposing an experimental (using small angle X-ray scattering and a computer simulation case study, which are meant as demonstrations of the possibilities we have at hand for investigating the delicate interfaces that connect (and divide protein molecules and the neighboring electrolyte solution.

  8. Blood gas sample spiking with total parenteral nutrition, lipid emulsion, and concentrated dextrose solutions as a model for predicting sample contamination based on glucose result.

    Science.gov (United States)

    Jara-Aguirre, Jose C; Smeets, Steven W; Wockenfus, Amy M; Karon, Brad S

    2018-05-01

    Evaluate the effects of blood gas sample contamination with total parenteral nutrition (TPN)/lipid emulsion and dextrose 50% (D50) solutions on blood gas and electrolyte measurement; and determine whether glucose concentration can predict blood gas sample contamination with TPN/lipid emulsion or D50. Residual lithium heparin arterial blood gas samples were spiked with TPN/lipid emulsion (0 to 15%) and D50 solutions (0 to 2.5%). Blood gas (pH, pCO2, pO2), electrolytes (Na+, K+ ionized calcium) and hemoglobin were measured with a Radiometer ABL90. Glucose concentration was measured in separated plasma by Roche Cobas c501. Chart review of neonatal blood gas results with glucose >300 mg/dL (>16.65 mmol/L) over a seven month period was performed to determine whether repeat (within 4 h) blood gas results suggested pre-analytical errors in blood gas results. Results were used to determine whether a glucose threshold could predict contamination resulting in blood gas and electrolyte results with greater than laboratory-defined allowable error. Samples spiked with 5% or more TPN/lipid emulsion solution or 1% D50 showed glucose concentration >500 mg/dL (>27.75 mmol/L) and produced blood gas (pH, pO 2 , pCO 2 ) results with greater than laboratory-defined allowable error. TPN/lipid emulsion, but not D50, produced greater than allowable error in electrolyte (Na + ,K + ,Ca ++ ,Hb) results at these concentrations. Based on chart review of 144 neonatal blood gas results with glucose >250 mg/dL received over seven months, four of ten neonatal intensive care unit (NICU) patients with glucose results >500 mg/dL and repeat blood gas results within 4 h had results highly suggestive of pre-analytical error. Only 3 of 36 NICU patients with glucose results 300-500 mg/dL and repeat blood gas results within 4 h had clear pre-analytical errors in blood gas results. Glucose concentration can be used as an indicator of significant blood sample contamination with either TPN

  9. Reliable structural interpretation of small-angle scattering data from bio-molecules in solution--the importance of quality control and a standard reporting framework.

    Science.gov (United States)

    Jacques, David A; Guss, Jules Mitchell; Trewhella, Jill

    2012-05-17

    Small-angle scattering is becoming an increasingly popular tool for the study of bio-molecular structures in solution. The large number of publications with 3D-structural models generated from small-angle solution scattering data has led to a growing consensus for the need to establish a standard reporting framework for their publication. The International Union of Crystallography recently established a set of guidelines for the necessary information required for the publication of such structural models. Here we describe the rationale for these guidelines and the importance of standardising the way in which small-angle scattering data from bio-molecules and associated structural interpretations are reported.

  10. Reliable structural interpretation of small-angle scattering data from bio-molecules in solution - the importance of quality control and a standard reporting framework

    Directory of Open Access Journals (Sweden)

    Jacques David A

    2012-05-01

    Full Text Available Abstract Small-angle scattering is becoming an increasingly popular tool for the study of bio-molecular structures in solution. The large number of publications with 3D-structural models generated from small-angle solution scattering data has led to a growing consensus for the need to establish a standard reporting framework for their publication. The International Union of Crystallography recently established a set of guidelines for the necessary information required for the publication of such structural models. Here we describe the rationale for these guidelines and the importance of standardising the way in which small-angle scattering data from bio-molecules and associated structural interpretations are reported.

  11. Shrinkage-based diagonal Hotelling’s tests for high-dimensional small sample size data

    KAUST Repository

    Dong, Kai

    2015-09-16

    DNA sequencing techniques bring novel tools and also statistical challenges to genetic research. In addition to detecting differentially expressed genes, testing the significance of gene sets or pathway analysis has been recognized as an equally important problem. Owing to the “large pp small nn” paradigm, the traditional Hotelling’s T2T2 test suffers from the singularity problem and therefore is not valid in this setting. In this paper, we propose a shrinkage-based diagonal Hotelling’s test for both one-sample and two-sample cases. We also suggest several different ways to derive the approximate null distribution under different scenarios of pp and nn for our proposed shrinkage-based test. Simulation studies show that the proposed method performs comparably to existing competitors when nn is moderate or large, but it is better when nn is small. In addition, we analyze four gene expression data sets and they demonstrate the advantage of our proposed shrinkage-based diagonal Hotelling’s test.

  12. Shrinkage-based diagonal Hotelling’s tests for high-dimensional small sample size data

    KAUST Repository

    Dong, Kai; Pang, Herbert; Tong, Tiejun; Genton, Marc G.

    2015-01-01

    DNA sequencing techniques bring novel tools and also statistical challenges to genetic research. In addition to detecting differentially expressed genes, testing the significance of gene sets or pathway analysis has been recognized as an equally important problem. Owing to the “large pp small nn” paradigm, the traditional Hotelling’s T2T2 test suffers from the singularity problem and therefore is not valid in this setting. In this paper, we propose a shrinkage-based diagonal Hotelling’s test for both one-sample and two-sample cases. We also suggest several different ways to derive the approximate null distribution under different scenarios of pp and nn for our proposed shrinkage-based test. Simulation studies show that the proposed method performs comparably to existing competitors when nn is moderate or large, but it is better when nn is small. In addition, we analyze four gene expression data sets and they demonstrate the advantage of our proposed shrinkage-based diagonal Hotelling’s test.

  13. ANALYSIS OF MONTE CARLO SIMULATION SAMPLING TECHNIQUES ON SMALL SIGNAL STABILITY OF WIND GENERATOR- CONNECTED POWER SYSTEM

    Directory of Open Access Journals (Sweden)

    TEMITOPE RAPHAEL AYODELE

    2016-04-01

    Full Text Available Monte Carlo simulation using Simple Random Sampling (SRS technique is popularly known for its ability to handle complex uncertainty problems. However, to produce a reasonable result, it requires huge sample size. This makes it to be computationally expensive, time consuming and unfit for online power system applications. In this article, the performance of Latin Hypercube Sampling (LHS technique is explored and compared with SRS in term of accuracy, robustness and speed for small signal stability application in a wind generator-connected power system. The analysis is performed using probabilistic techniques via eigenvalue analysis on two standard networks (Single Machine Infinite Bus and IEEE 16–machine 68 bus test system. The accuracy of the two sampling techniques is determined by comparing their different sample sizes with the IDEAL (conventional. The robustness is determined based on a significant variance reduction when the experiment is repeated 100 times with different sample sizes using the two sampling techniques in turn. Some of the results show that sample sizes generated from LHS for small signal stability application produces the same result as that of the IDEAL values starting from 100 sample size. This shows that about 100 sample size of random variable generated using LHS method is good enough to produce reasonable results for practical purpose in small signal stability application. It is also revealed that LHS has the least variance when the experiment is repeated 100 times compared to SRS techniques. This signifies the robustness of LHS over that of SRS techniques. 100 sample size of LHS produces the same result as that of the conventional method consisting of 50000 sample size. The reduced sample size required by LHS gives it computational speed advantage (about six times over the conventional method.

  14. Use of a commercially available nucleating agent to control the morphological development of solution-processed small molecule bulk heterojunction organic solar cells

    KAUST Repository

    Sharenko, Alexander; Treat, Neil D.; Love, John A.; Toney, Michael F.; Stingelin, Natalie; Nguyen, Thuc-Quyen

    2014-01-01

    © the Partner Organisations 2014. The nucleating agent DMDBS is used to modulate the crystallization of solution-processed small molecule donor molecules in bulk heterojunction organic photovoltaic (BHJ OPV) devices. This control over donor molecule crystallization leads to a reduction in optimized thermal annealing times as well as smaller donor molecule crystallites, and therefore more efficient devices, when using an excessive amount of solvent additive. We therefore demonstrate the use of nucleating agents as a powerful and versatile processing strategy for solution-processed, small molecule BHJ OPVs. This journal is

  15. Use of a commercially available nucleating agent to control the morphological development of solution-processed small molecule bulk heterojunction organic solar cells

    KAUST Repository

    Sharenko, Alexander

    2014-08-12

    © the Partner Organisations 2014. The nucleating agent DMDBS is used to modulate the crystallization of solution-processed small molecule donor molecules in bulk heterojunction organic photovoltaic (BHJ OPV) devices. This control over donor molecule crystallization leads to a reduction in optimized thermal annealing times as well as smaller donor molecule crystallites, and therefore more efficient devices, when using an excessive amount of solvent additive. We therefore demonstrate the use of nucleating agents as a powerful and versatile processing strategy for solution-processed, small molecule BHJ OPVs. This journal is

  16. Calculation of coincidence summing corrections for a specific small soil sample geometry

    Energy Technology Data Exchange (ETDEWEB)

    Helmer, R.G.; Gehrke, R.J.

    1996-10-01

    Previously, a system was developed at the INEL for measuring the {gamma}-ray emitting nuclides in small soil samples for the purpose of environmental monitoring. These samples were counted close to a {approx}20% Ge detector and, therefore, it was necessary to take into account the coincidence summing that occurs for some nuclides. In order to improve the technical basis for the coincidence summing corrections, the authors have carried out a study of the variation in the coincidence summing probability with position within the sample volume. A Monte Carlo electron and photon transport code (CYLTRAN) was used to compute peak and total efficiencies for various photon energies from 30 to 2,000 keV at 30 points throughout the sample volume. The geometry for these calculations included the various components of the detector and source along with the shielding. The associated coincidence summing corrections were computed at these 30 positions in the sample volume and then averaged for the whole source. The influence of the soil and the detector shielding on the efficiencies was investigated.

  17. Speeding Up Non-Parametric Bootstrap Computations for Statistics Based on Sample Moments in Small/Moderate Sample Size Applications.

    Directory of Open Access Journals (Sweden)

    Elias Chaibub Neto

    Full Text Available In this paper we propose a vectorized implementation of the non-parametric bootstrap for statistics based on sample moments. Basically, we adopt the multinomial sampling formulation of the non-parametric bootstrap, and compute bootstrap replications of sample moment statistics by simply weighting the observed data according to multinomial counts instead of evaluating the statistic on a resampled version of the observed data. Using this formulation we can generate a matrix of bootstrap weights and compute the entire vector of bootstrap replications with a few matrix multiplications. Vectorization is particularly important for matrix-oriented programming languages such as R, where matrix/vector calculations tend to be faster than scalar operations implemented in a loop. We illustrate the application of the vectorized implementation in real and simulated data sets, when bootstrapping Pearson's sample correlation coefficient, and compared its performance against two state-of-the-art R implementations of the non-parametric bootstrap, as well as a straightforward one based on a for loop. Our investigations spanned varying sample sizes and number of bootstrap replications. The vectorized bootstrap compared favorably against the state-of-the-art implementations in all cases tested, and was remarkably/considerably faster for small/moderate sample sizes. The same results were observed in the comparison with the straightforward implementation, except for large sample sizes, where the vectorized bootstrap was slightly slower than the straightforward implementation due to increased time expenditures in the generation of weight matrices via multinomial sampling.

  18. Mixing of process heels, process solutions, and recycle streams: Results of the small-scale radioactive tests

    International Nuclear Information System (INIS)

    Lumetta, G.J.; Bramson, J.P.; Farmer III, O.T.; Greenwood, L.R.; Hoopes, F.V.; Mann, M.A.; Steele, M.J.; Steele, R.T.; Swoboda, R.G.; Urie, M.W.

    2000-01-01

    Various recycle streams will be combined with the low-activity waste (LAW) or the high-level waste (HLW) feed solutions during the processing of the Hanford tank wastes by BNFL, Inc. In addition, the LAW and HLW feed solutions will also be mixed with heels present in the processing equipment. This report describes the results of a test conducted by Battelle to assess the effects of mixing specific process streams. Observations were made regarding adverse reactions (mainly precipitation) and effects on the Tc oxidation state (as indicated by K d measurements with SuperLigreg s ign 639). The work was conducted according to test plan BNFL-TP-29953-023, Rev. 0, Small Scale Mixing of Process Heels, Solutions, and Recycle Streams. The test went according to plan, with only minor deviations from the test plan. The deviations from the test plan are discussed in the experimental section

  19. Direct protein quantification in complex sample solutions by surface-engineered nanorod probes

    KAUST Repository

    Schrittwieser, Stefan

    2017-06-30

    Detecting biomarkers from complex sample solutions is the key objective of molecular diagnostics. Being able to do so in a simple approach that does not require laborious sample preparation, sophisticated equipment and trained staff is vital for point-of-care applications. Here, we report on the specific detection of the breast cancer biomarker sHER2 directly from serum and saliva samples by a nanorod-based homogeneous biosensing approach, which is easy to operate as it only requires mixing of the samples with the nanorod probes. By careful nanorod surface engineering and homogeneous assay design, we demonstrate that the formation of a protein corona around the nanoparticles does not limit the applicability of our detection method, but on the contrary enables us to conduct in-situ reference measurements, thus further strengthening the point-of-care applicability of our method. Making use of sandwich assays on top of the nanorods, we obtain a limit of detection of 110 pM and 470 pM in 10-fold diluted spiked saliva and serum samples, respectively. In conclusion, our results open up numerous applications in direct protein biomarker quantification, specifically in point-of-care settings where resources are limited and ease-of-use is of essence.

  20. Direct protein quantification in complex sample solutions by surface-engineered nanorod probes

    KAUST Repository

    Schrittwieser, Stefan; Pelaz, Beatriz; Parak, Wolfgang J.; Lentijo Mozo, Sergio; Soulantica, Katerina; Dieckhoff, Jan; Ludwig, Frank; Schotter, Joerg

    2017-01-01

    Detecting biomarkers from complex sample solutions is the key objective of molecular diagnostics. Being able to do so in a simple approach that does not require laborious sample preparation, sophisticated equipment and trained staff is vital for point-of-care applications. Here, we report on the specific detection of the breast cancer biomarker sHER2 directly from serum and saliva samples by a nanorod-based homogeneous biosensing approach, which is easy to operate as it only requires mixing of the samples with the nanorod probes. By careful nanorod surface engineering and homogeneous assay design, we demonstrate that the formation of a protein corona around the nanoparticles does not limit the applicability of our detection method, but on the contrary enables us to conduct in-situ reference measurements, thus further strengthening the point-of-care applicability of our method. Making use of sandwich assays on top of the nanorods, we obtain a limit of detection of 110 pM and 470 pM in 10-fold diluted spiked saliva and serum samples, respectively. In conclusion, our results open up numerous applications in direct protein biomarker quantification, specifically in point-of-care settings where resources are limited and ease-of-use is of essence.

  1. Comparison of soil solution sampling techniques to assess metal fluxes from contaminated soil to groundwater.

    Science.gov (United States)

    Coutelot, F; Sappin-Didier, V; Keller, C; Atteia, O

    2014-12-01

    The unsaturated zone plays a major role in elemental fluxes in terrestrial ecosystems. A representative chemical analysis of soil pore water is required for the interpretation of soil chemical phenomena and particularly to assess Trace Elements (TEs) mobility. This requires an optimal sampling system to avoid modification of the extracted soil water chemistry and allow for an accurate estimation of solute fluxes. In this paper, the chemical composition of soil solutions sampled by Rhizon® samplers connected to a standard syringe was compared to two other types of suction probes (Rhizon® + vacuum tube and Rhizon® + diverted flow system). We investigated the effects of different vacuum application procedures on concentrations of spiked elements (Cr, As, Zn) mixed as powder into the first 20 cm of 100-cm columns and non-spiked elements (Ca, Na, Mg) concentrations in two types of columns (SiO2 sand and a mixture of kaolinite + SiO2 sand substrates). Rhizon® was installed at different depths. The metals concentrations showed that (i) in sand, peak concentrations cannot be correctly sampled, thus the flux cannot be estimated, and the errors can easily reach a factor 2; (ii) in sand + clay columns, peak concentrations were larger, indicating that they could be sampled but, due to sorption on clay, it was not possible to compare fluxes at different depths. The different samplers tested were not able to reflect the elemental flux to groundwater and, although the Rhizon® + syringe device was more accurate, the best solution remains to be the use of a lysimeter, whose bottom is kept continuously at a suction close to the one existing in the soil.

  2. Colloid mobilization and heavy metal transport in the sampling of soil solution from Duckum soil in South Korea.

    Science.gov (United States)

    Lee, Seyong; Ko, Il-Won; Yoon, In-Ho; Kim, Dong-Wook; Kim, Kyoung-Woong

    2018-03-24

    Colloid mobilization is a significant process governing colloid-associated transport of heavy metals in subsurface environments. It has been studied for the last three decades to understand this process. However, colloid mobilization and heavy metal transport in soil solutions have rarely been studied using soils in South Korea. We investigated the colloid mobilization in a variety of flow rates during sampling soil solutions in sand columns. The colloid concentrations were increased at low flow rates and in saturated regimes. Colloid concentrations increased 1000-fold higher at pH 9.2 than at pH 7.3 in the absence of 10 mM NaCl solution. In addition, those were fourfold higher in the absence than in the presence of the NaCl solution at pH 9.2. It was suggested that the mobility of colloids should be enhanced in porous media under the basic conditions and the low ionic strength. In real field soils, the concentrations of As, Cr, and Pb in soil solutions increased with the increase in colloid concentrations at initial momentarily changed soil water pressure, whereas the concentrations of Cd, Cu, Fe, Ni, Al, and Co lagged behind the colloid release. Therefore, physicochemical changes and heavy metal characteristics have important implications for colloid-facilitated transport during sampling soil solutions.

  3. Investigation of hydrophobic substrates for solution residue analysis utilizing an ambient desorption liquid sampling-atmospheric pressure glow discharge microplasma.

    Science.gov (United States)

    Paing, Htoo W; Marcus, R Kenneth

    2018-03-12

    A practical method for preparation of solution residue samples for analysis utilizing the ambient desorption liquid sampling-atmospheric pressure glow discharge optical emission spectroscopy (AD-LS-APGD-OES) microplasma is described. Initial efforts involving placement of solution aliquots in wells drilled into copper substrates, proved unsuccessful. A design-of-experiment (DOE) approach was carried out to determine influential factors during sample deposition including solution volume, solute concentration, number of droplets deposited, and the solution matrix. These various aspects are manifested in the mass of analyte deposited as well as the size/shape of the product residue. Statistical analysis demonstrated that only those initial attributes were significant factors towards the emission response of the analyte. Various approaches were investigated to better control the location/uniformity of the deposited sample. Three alternative substrates, a glass slide, a poly(tetrafluoro)ethylene (PTFE) sheet, and a polydimethylsiloxane (PDMS)-coated glass slide, were evaluated towards the microplasma analytical performance. Co-deposition with simple organic dyes provided an accurate means of determining the location of the analyte with only minor influence on emission responses. The PDMS-coated glass provided the best performance by virtue of its providing a uniform spatial distribution of the residue material. This uniformity yielded an improved limits of detection by approximately 22× for 20 μL and 4 x for 2 μL over the other two substrates. While they operate by fundamentally different processes, this choice of substrate is not restricted to the LS-APGD, but may also be applicable to other AD methods such as DESI, DART, or LIBS. Further developments will be directed towards a field-deployable ambient desorption OES source for quantitative analysis of microvolume solution residues of nuclear forensics importance.

  4. The use of commercially available PC-interface cards for elemental mapping in small samples using XRF

    International Nuclear Information System (INIS)

    Abu Bakar bin Ghazali; Hoyes Garnet

    1991-01-01

    This paper demonstrates the use of ADC and reed relay cards to scan a small sample for acquiring data of X-ray fluorescence. The result shows the distribution of an element such as zinc content in the sample by means of colours, signifying the concentration

  5. A novel device for batch-wise isolation of α-cellulose from small-amount wholewood samples

    OpenAIRE

    T. Wieloch; Gerhard Helle; Ingo Heinrich; Michael Voigt; P. Schyma

    2011-01-01

    A novel device for the chemical isolation of α-cellulose from wholewood material of tree rings was designed by the Potsdam Dendro Laboratory. It allows the simultaneous treatment of up to several hundred micro samples. Key features are the batch-wise exchange of the chemical solutions, the reusability of all major parts and the easy and unambiguous labelling of each individual sample. Compared to classical methods labour intensity and running costs are significantly reduced.

  6. Structure of polyacrylic acid and polymethacrylic acid solutions: a small angle neutron scattering study

    Energy Technology Data Exchange (ETDEWEB)

    Moussaid, A. (Lab. d' Ultrasons et de Dynamique des Fluides Complexes, Univ. Louis Pasteur, 67 - Strasbourg (France)); Schosseler, F. (Lab. d' Ultrasons et de Dynamique des Fluides Complexes, Univ. Louis Pasteur, 67 - Strasbourg (France)); Munch, J.P. (Lab. d' Ultrasons et de Dynamique des Fluides Complexes, Univ. Louis Pasteur, 67 - Strasbourg (France)); Candau, S.J. (Lab. d' Ultrasons et de Dynamique des Fluides Complexes, Univ. Louis Pasteur, 67 - Strasbourg (France))

    1993-04-01

    The intensity scattered from polyacrylic acid and polymethacrylic acid solutions has been measured by small angle neutron scattering experiments. The influence of polymer concentration, ionization degree, temperature and salt content has been investigated. Results are in qualitative agreement with a model which predicts the existence of microphases in the unstable region of the phase diagram. Quantitative comparison with the theory is performed by fitting the theoretical structure factor to the experimental data. For a narrow range of ionization degrees nearly quantitative agreement with the theory is found for the polyacrylic acid system. (orig.).

  7. Structure of polyacrylic acid and polymethacrylic acid solutions : a small angle neutron scattering study

    Science.gov (United States)

    Moussaid, A.; Schosseler, F.; Munch, J. P.; Candau, S. J.

    1993-04-01

    The intensity scattered from polyacrylic acid and polymethacrylic acid solutions has been measured by small angle neutron scattering experiemnts. The influence of polymer concentration, ionization degree, temperature and salt content has been investigated. Results are in qualitative agreement with a model which predicts the existence of microphases in the unstable region of the phase diagram. Quantitative comparison with the theory is performed by fitting the theoretical structure factor to the experimental data. For a narrow range of ionizaiton degrees nearly quantitative agreement with the theory is found for the polyacrylic acide system.

  8. Correcting Model Fit Criteria for Small Sample Latent Growth Models with Incomplete Data

    Science.gov (United States)

    McNeish, Daniel; Harring, Jeffrey R.

    2017-01-01

    To date, small sample problems with latent growth models (LGMs) have not received the amount of attention in the literature as related mixed-effect models (MEMs). Although many models can be interchangeably framed as a LGM or a MEM, LGMs uniquely provide criteria to assess global data-model fit. However, previous studies have demonstrated poor…

  9. Using Data-Dependent Priors to Mitigate Small Sample Bias in Latent Growth Models: A Discussion and Illustration Using M"plus"

    Science.gov (United States)

    McNeish, Daniel M.

    2016-01-01

    Mixed-effects models (MEMs) and latent growth models (LGMs) are often considered interchangeable save the discipline-specific nomenclature. Software implementations of these models, however, are not interchangeable, particularly with small sample sizes. Restricted maximum likelihood estimation that mitigates small sample bias in MEMs has not been…

  10. X-ray small angle scattering of polymer solutions

    International Nuclear Information System (INIS)

    Koyama, Ryuzo

    1975-01-01

    In recent papers, the calculated results were reported on the angular dependence of the intensity of scattered light or X-ray by chain polymers, on the basis of a stiff chain model. As the results, the curves of S 2 P (theta) corresponding to Kratky plot, for different molecular expansion, showed a plateau, and the height of the plateau was proportional to the inverse of molecular expansion coefficient α 2 . But as seen later, there is some possibility that the assumption made in the calculation overestimated the expansion of small segments which theoretically determines scattering curves at large scattering angles, such as the plateau. Accordingly, modified calculation was carried out by adopting the stiff chain polymer model as the previous case. When the contour length of a chain segment is very long, it can be treated approximately as a Gaussian coil, thus the equation for a chain segment expansion coefficient α (t) was obtained. Then the mean square distance of chain segments of polymer molecules was able to be determined, and the equation for a particle scattering factor P(theta) was obtained. The numerical calculation of P(theta) showed that this modified assumption considerably decreased the effect of molecular expansion on P(theta), and the curves of S 2 P(theta) increased monotonously without showing the plateau. The result of this calculation was compared with the experimental curves of polystyrene-toluene solution, and the agreement better than before was obtained. (Kako, I.)

  11. Simultaneous determination of iodide and iodate in soil solution samples by HPLC with electrochemical detection and post-column reaction method

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Akira; Takaku, Yuichi; Hisamatsu, Shun' ichi [Department of Radioecology, Institute for Environmental Sciences, Aomori 039-3212 (Japan); Tsukada, Hirofumi [Department of Radioecology, Institute for Environmental Sciences, Aomori 039-3212 (Japan); Institute of Environmental Radioactivity, Fukushima University, Fukushima 960-1196 (Japan)

    2014-07-01

    Iodine-129 (half-life 1.6 x 10{sup 7} y) discharged into the atmosphere from nuclear facilities (e.g., a nuclear fuel reprocessing plant) is partly deposited on land and introduced into soil. Stable iodine ({sup 127}I) can be used as a natural analogue to predict the long-term behavior of {sup 129}I in the terrestrial environment. Iodine in soil mainly exists as I{sup -}, IO{sub 3}{sup -}, and organic iodine. Because the mobilities of these species in soil are quite different, iodine speciation in soil solution is a key for predicting the behavior of iodine in soil. We developed a new speciation method suitable for routine analysis of many soil solution samples, and successfully applied the method to real samples. The method involves determining the concentration of total iodine and then separately measuring the I{sup -} and IO{sub 3}{sup -} concentrations with an HPLC system. The HPLC system (Nano-space SI-2; Shiseido, Tokyo, Japan) consisted of a UV/Vis spectrometer and an electrochemical (amperometric) detector (50 mV Ag/AgCl). Two reverse-phase columns (2.0 x 50 mm Capcel Pak DD C8 and 2.0 x 250 mm Capcel Pak MGII C18; Shiseido) were serially connected, and a switching valve was set between them. I{sup -} and IO{sub 3}{sup -} in the sample solution were separated from each other in the DD C8 column. IO{sub 3}{sup -} eluted first from the column, while I{sup -} was retained. After IO{sub 3}{sup -} was further separated from other halogen acids with the C18 column, IO{sub 3}{sup -} was reacted with KBr and o-dianisidine in a thermos-reactor (90 deg. C), and absorption at 450 nm was measured with the UV/Vis spectrometer. The concentration of I{sup -} eluted from the first column was determined with the electrochemical detector. To determine the concentration of total iodine in the sample solution, organic iodine was decomposed by UV irradiation (UV digester 705; Metrohm AG, Herisau, Switzerland) for 30 min at 20 deg. C. The iodine in the solution was reduced to I

  12. Acoustically levitated droplets: a contactless sampling method for fluorescence studies.

    Science.gov (United States)

    Leiterer, Jork; Grabolle, Markus; Rurack, Knut; Resch-Genger, Ute; Ziegler, Jan; Nann, Thomas; Panne, Ulrich

    2008-01-01

    Acoustic levitation is used as a new tool to study concentration-dependent processes in fluorescence spectroscopy. With this technique, small amounts of liquid and solid samples can be measured without the need for sample supports or containers, which often limits signal acquisition and can even alter sample properties due to interactions with the support material. We demonstrate that, because of the small sample volume, fluorescence measurements at high concentrations of an organic dye are possible without the limitation of inner-filter effects, which hamper such experiments in conventional, cuvette-based measurements. Furthermore, we show that acoustic levitation of liquid samples provides an experimentally simple way to study distance-dependent fluorescence modulations in semiconductor nanocrystals. The evaporation of the solvent during levitation leads to a continuous increase of solute concentration and can easily be monitored by laser-induced fluorescence.

  13. Oral contrast agents for small bowel distension in MRI: influence of the osmolarity for small bowel distention

    International Nuclear Information System (INIS)

    Ajaj, Waleed; Kuehle, Christiane; Nuefer, Michael; Goehde, Susanne C.; Lauenstein, Thomas C.; Goyen, Mathias; Schneemann, Hubert; Ruehm, Stefan G.

    2005-01-01

    To assess the effect of the osmolarity for small bowel distension in MRI, ten volunteers ingested at two separate occasions negative oral contrast agents with different quantity and osmolarity: (1) a water solution combined with 2.0% sorbitol and 0.2% locus bean gum (LBG) with a quantity of 1500 ml and an osmolarity of 148 mOsmol/l, (2) a water solution combined with 2.0% sorbitol and 2.0% barium sulphate with a quantity of 1000 ml and an osmolarity of 194 mOsmol/l. Small bowel distension was quantified on coronal 2D-TrueFISP images by measuring the small bowel diameters. There were no statistically significant differences in mean small bowel diameter between both contrast agents. The mean small bowel distension was 19.2 mm after ingestion of 1500 ml of sorbitol-LBG solution and 19.0 mm after ingestion of 1000-ml sorbitol-barium sulphate solution. Furthermore, all volunteers found the ingestion of 1000-ml solution more pleasant than the 1500-ml solution. The ingestion of 1000 ml of sorbitol-barium sulphate solution led to a sufficient small bowel distension compared to 1500 ml of sorbitol-LBG solution. The side effect rate of both solutions was low. Based on these data, we recommend a quantity of 1000 ml of sorbitol-barium sulphate solution as an alternative for 1500-ml sorbitol-LBG solution for optimal bowel distension. (orig.)

  14. Small Column Ion Exchange Analysis for Removal of Cesium from SRS Low Curie Salt Solutions Using Crystalline Silicotitanate (CST) Resin

    International Nuclear Information System (INIS)

    ALEMAN, SEBASTIAN

    2004-01-01

    Savannah River Technology Center (SRTC) researchers modeled ion exchange removal of cesium from dissolved salt waste solutions. The results assist in evaluating proposed configurations for an ion exchange process to remove residual cesium from low curie waste streams. A process for polishing (i.e., removing small amounts) of cesium may prove useful should supernate draining fail to meet the Low Curie Salt (LCS) target limit of 0.1 Ci of Cs-137 per gallon of salt solution. Cesium loading isotherms and column breakthrough curves for Low Curie dissolved salt solutions were computed to provide performance predictions for various column designs

  15. Using CMB spectral distortions to distinguish between dark matter solutions to the small-scale crisis

    Energy Technology Data Exchange (ETDEWEB)

    Diacoumis, James A.D.; Wong, Yvonne Y.Y., E-mail: j.diacoumis@unsw.edu.au, E-mail: yvonne.y.wong@unsw.edu.au [School of Physics, The University of New South Wales, Sydney NSW 2052 (Australia)

    2017-09-01

    The dissipation of small-scale perturbations in the early universe produces a distortion in the blackbody spectrum of cosmic microwave background photons. In this work, we propose to use these distortions as a probe of the microphysics of dark matter on scales 1 Mpc{sup -1}∼< k ∼< 10{sup 4} Mpc{sup -1}. We consider in particular models in which the dark matter is kinetically coupled to either neutrinos or photons until shortly before recombination, and compute the photon heating rate and the resultant μ-distortion in both cases. We show that the μ-parameter is generally enhanced relative to ΛCDM for interactions with neutrinos, and may be either enhanced or suppressed in the case of interactions with photons. The deviations from the ΛCDM signal are potentially within the sensitivity reach of a PRISM-like experiment if σ{sub DM-γ} ∼> 1.1 × 10{sup -30} (m{sub DM}/GeV) cm{sup 2} and σ{sub DM-ν} ∼> 4.8 × 10{sup -32} (m{sub DM}/GeV) cm{sup 2} for time-independent cross sections, and σ{sup 0}{sub DM-γ} ∼> 1.8 × 10{sup -40} (m{sub DM}/GeV) cm{sup 2} and σ{sup 0}{sub DM-ν} ∼> 2.5 × 10{sup -47} (m{sub DM}/GeV) cm{sup 2} for cross sections scaling as temperature squared, coinciding with the parameter regions in which late kinetic decoupling may serve as a solution to the small-scale crisis. Furthermore, these μ-distortion signals differ from those of warm dark matter (no deviation from ΛCDM) and a suppressed primordial power spectrum (a strongly suppressed or negative μ-parameter), demonstrating that CMB spectral distortion can potentially be used to distinguish between solutions to the small-scale crisis.

  16. Sequential determination of nickel and cadmium in tobacco, molasses and refill solutions for e-cigarettes samples by molecular fluorescence.

    Science.gov (United States)

    Talio, María Carolina; Alesso, Magdalena; Acosta, Mariano; Wills, Verónica S; Fernández, Liliana P

    2017-11-01

    In this work, a new procedure was developed for separation and preconcentration of nickel(II) and cadmium(II) in several and varied tobacco samples. Tobacco samples were selected considering the main products consumed by segments of the population, in particular the age (youth) and lifestyle of the consumer. To guarantee representative samples, a randomized strategy of sampling was used. In the first step, a chemofiltration on nylon membrane is carried out employing eosin (Eo) and carbon nanotubes dispersed in sodium dodecylsulfate (SDS) solution (phosphate buffer pH 7). In this condition, Ni(II) was selectively retained on the solid support. After that, the filtrate liquid with Cd(II) was re-conditioned with acetic acid /acetate buffer solution (pH 5) and followed by detection. A spectrofluorimetric determination of both metals was carried out, on the solid support and the filtered aqueous solution, for Ni(II) and Cd(II), respectively. The solid surface fluorescence (SSF) determination was performed at λ em = 545nm (λ ex = 515nm) for Ni(II)-Eo complex and the fluorescence of Cd(II)-Eo was quantified in aqueous solution using λ em = 565nm (λ ex = 540nm). The calibration graphs resulted linear in a range of 0.058-29.35μgL -1 for Ni(II) and 0.124-56.20μgL -1 for Cd(II), with detection limits of 0.019 and 0.041μgL -1 (S/N = 3). The developed methodology shows good sensitivity and adequate selectivity, and it was successfully applied to the determination of trace amounts of nickel and cadmium present in tobacco samples (refill solutions for e-cigarettes, snuff used in narguille (molasses) and traditional tobacco) with satisfactory results. The new methodology was validated by ICP-MS with adequate agreement. The proposed methodology represents a novel fluorescence application to Ni(II) and Cd(II) quantification with sensitivity and accuracy similar to atomic spectroscopies, introducing for the first time the quenching effect on SSF. Copyright © 2017 Elsevier B

  17. Evaluation of Approaches to Analyzing Continuous Correlated Eye Data When Sample Size Is Small.

    Science.gov (United States)

    Huang, Jing; Huang, Jiayan; Chen, Yong; Ying, Gui-Shuang

    2018-02-01

    To evaluate the performance of commonly used statistical methods for analyzing continuous correlated eye data when sample size is small. We simulated correlated continuous data from two designs: (1) two eyes of a subject in two comparison groups; (2) two eyes of a subject in the same comparison group, under various sample size (5-50), inter-eye correlation (0-0.75) and effect size (0-0.8). Simulated data were analyzed using paired t-test, two sample t-test, Wald test and score test using the generalized estimating equations (GEE) and F-test using linear mixed effects model (LMM). We compared type I error rates and statistical powers, and demonstrated analysis approaches through analyzing two real datasets. In design 1, paired t-test and LMM perform better than GEE, with nominal type 1 error rate and higher statistical power. In design 2, no test performs uniformly well: two sample t-test (average of two eyes or a random eye) achieves better control of type I error but yields lower statistical power. In both designs, the GEE Wald test inflates type I error rate and GEE score test has lower power. When sample size is small, some commonly used statistical methods do not perform well. Paired t-test and LMM perform best when two eyes of a subject are in two different comparison groups, and t-test using the average of two eyes performs best when the two eyes are in the same comparison group. When selecting the appropriate analysis approach the study design should be considered.

  18. Small-angle X-Ray analysis of macromolecular structure: the structure of protein NS2 (NEP) in solution

    Science.gov (United States)

    Shtykova, E. V.; Bogacheva, E. N.; Dadinova, L. A.; Jeffries, C. M.; Fedorova, N. V.; Golovko, A. O.; Baratova, L. A.; Batishchev, O. V.

    2017-11-01

    A complex structural analysis of nuclear export protein NS2 (NEP) of influenza virus A has been performed using bioinformatics predictive methods and small-angle X-ray scattering data. The behavior of NEP molecules in a solution (their aggregation, oligomerization, and dissociation, depending on the buffer composition) has been investigated. It was shown that stable associates are formed even in a conventional aqueous salt solution at physiological pH value. For the first time we have managed to get NEP dimers in solution, to analyze their structure, and to compare the models obtained using the method of the molecular tectonics with the spatial protein structure predicted by us using the bioinformatics methods. The results of the study provide a new insight into the structural features of nuclear export protein NS2 (NEP) of the influenza virus A, which is very important for viral infection development.

  19. Air Emissions Sampling from Vacuum Thermal Desorption for Mixed Wastes Designated with a Combustion Treatment Code for the Energy Solutions LLC Mixed Waste Facility

    International Nuclear Information System (INIS)

    Christensen, M.E.; Willoughby, O.H.

    2009-01-01

    EnergySolutions LLC is permitted by the State of Utah to treat organically-contaminated Mixed Waste by a vacuum thermal desorption (VTD) treatment process at its Clive, Utah treatment, storage, and disposal facility. The VTD process separates organics from organically-contaminated waste by heating the material in an inert atmosphere, and captures them as concentrated liquid by condensation. The majority of the radioactive materials present in the feed to the VTD are retained with the treated solids; the recovered aqueous and organic condensates are not radioactive. This is generally true when the radioactivity is present in solid form such as inorganic salts, metals or metallic oxides. The exception is when volatile radioactive materials are present such as radon gas, tritium, or carbon-14 organic chemicals. Volatile radioactive materials are a small fraction of the feed material. On August 28, 2006, EnergySolutions submitted a request to the USEPA for a variance to the Land Disposal Restrictions (LDR) standards for wastes designated with the combustion treatment code (CMBST). The final rule granting a site specific treatment variance was effective June 13, 2008. This variance is an alternative treatment standard to treatment by CMBST required for these wastes under USEPA's rules. The State of Utah provides oversight of the VTD processing operations. A demonstration test for treating CMBST-coded wastes was performed on April 29, 2008 through May 1, 2008. Three separate process cycles were conducted during this test. Both solid/liquid samples and emission samples were collected each day during the demonstration test. To adequately challenge the unit, feed material was spiked with trichloroethylene, o-cresol, dibenzofuran, and coal tar. Emission testing was conducted by EnergySolutions' emissions test contractor and sampling for radioactivity within the off-gas was completed by EnergySolutions' Health Physics department. This report discusses the emission testing

  20. Sensitivity and specificity of normality tests and consequences on reference interval accuracy at small sample size: a computer-simulation study.

    Science.gov (United States)

    Le Boedec, Kevin

    2016-12-01

    According to international guidelines, parametric methods must be chosen for RI construction when the sample size is small and the distribution is Gaussian. However, normality tests may not be accurate at small sample size. The purpose of the study was to evaluate normality test performance to properly identify samples extracted from a Gaussian population at small sample sizes, and assess the consequences on RI accuracy of applying parametric methods to samples that falsely identified the parent population as Gaussian. Samples of n = 60 and n = 30 values were randomly selected 100 times from simulated Gaussian, lognormal, and asymmetric populations of 10,000 values. The sensitivity and specificity of 4 normality tests were compared. Reference intervals were calculated using 6 different statistical methods from samples that falsely identified the parent population as Gaussian, and their accuracy was compared. Shapiro-Wilk and D'Agostino-Pearson tests were the best performing normality tests. However, their specificity was poor at sample size n = 30 (specificity for P Box-Cox transformation) on all samples regardless of their distribution or adjusting, the significance level of normality tests depending on sample size would limit the risk of constructing inaccurate RI. © 2016 American Society for Veterinary Clinical Pathology.

  1. Sampling Molecular Conformers in Solution with Quantum Mechanical Accuracy at a Nearly Molecular-Mechanics Cost.

    Science.gov (United States)

    Rosa, Marta; Micciarelli, Marco; Laio, Alessandro; Baroni, Stefano

    2016-09-13

    We introduce a method to evaluate the relative populations of different conformers of molecular species in solution, aiming at quantum mechanical accuracy, while keeping the computational cost at a nearly molecular-mechanics level. This goal is achieved by combining long classical molecular-dynamics simulations to sample the free-energy landscape of the system, advanced clustering techniques to identify the most relevant conformers, and thermodynamic perturbation theory to correct the resulting populations, using quantum-mechanical energies from density functional theory. A quantitative criterion for assessing the accuracy thus achieved is proposed. The resulting methodology is demonstrated in the specific case of cyanin (cyanidin-3-glucoside) in water solution.

  2. A Rational Approach for Discovering and Validating Cancer Markers in Very Small Samples Using Mass Spectrometry and ELISA Microarrays

    Directory of Open Access Journals (Sweden)

    Richard C. Zangar

    2004-01-01

    Full Text Available Identifying useful markers of cancer can be problematic due to limited amounts of sample. Some samples such as nipple aspirate fluid (NAF or early-stage tumors are inherently small. Other samples such as serum are collected in larger volumes but archives of these samples are very valuable and only small amounts of each sample may be available for a single study. Also, given the diverse nature of cancer and the inherent variability in individual protein levels, it seems likely that the best approach to screen for cancer will be to determine the profile of a battery of proteins. As a result, a major challenge in identifying protein markers of disease is the ability to screen many proteins using very small amounts of sample. In this review, we outline some technological advances in proteomics that greatly advance this capability. Specifically, we propose a strategy for identifying markers of breast cancer in NAF that utilizes mass spectrometry (MS to simultaneously screen hundreds or thousands of proteins in each sample. The best potential markers identified by the MS analysis can then be extensively characterized using an ELISA microarray assay. Because the microarray analysis is quantitative and large numbers of samples can be efficiently analyzed, this approach offers the ability to rapidly assess a battery of selected proteins in a manner that is directly relevant to traditional clinical assays.

  3. Microdochium nivale and Microdochium majus in seed samples of Danish small grain cereals

    DEFF Research Database (Denmark)

    Nielsen, L. K.; Justesen, A. F.; Jensen, J. D.

    2013-01-01

    Microdochium nivale and Microdochium majus are two of fungal species found in the Fusarium Head Blight (FHB) complex infecting small grain cereals. Quantitative real-time PCR assays were designed to separate the two Microdochium species based on the translation elongation factor 1a gene (TEF-1a......) and used to analyse a total of 374 seed samples of wheat, barley, triticale, rye and oat sampled from farmers’ fields across Denmark from 2003 to 2007. Both fungal species were detected in the five cereal species but M. majus showed a higher prevalence compared to M. nivale in most years in all cereal...... species except rye, in which M. nivale represented a larger proportion of the biomass and was more prevalent than M. majus in some samples. Historical samples of wheat and barley from 1957 to 2000 similarly showed a strong prevalence of M. majus over M. nivale indicating that M. majus has been the main...

  4. Glycan characterization of the NIST RM monoclonal antibody using a total analytical solution: From sample preparation to data analysis.

    Science.gov (United States)

    Hilliard, Mark; Alley, William R; McManus, Ciara A; Yu, Ying Qing; Hallinan, Sinead; Gebler, John; Rudd, Pauline M

    Glycosylation is an important attribute of biopharmaceutical products to monitor from development through production. However, glycosylation analysis has traditionally been a time-consuming process with long sample preparation protocols and manual interpretation of the data. To address the challenges associated with glycan analysis, we developed a streamlined analytical solution that covers the entire process from sample preparation to data analysis. In this communication, we describe the complete analytical solution that begins with a simplified and fast N-linked glycan sample preparation protocol that can be completed in less than 1 hr. The sample preparation includes labelling with RapiFluor-MS tag to improve both fluorescence (FLR) and mass spectral (MS) sensitivities. Following HILIC-UPLC/FLR/MS analyses, the data are processed and a library search based on glucose units has been included to expedite the task of structural assignment. We then applied this total analytical solution to characterize the glycosylation of the NIST Reference Material mAb 8761. For this glycoprotein, we confidently identified 35 N-linked glycans and all three major classes, high mannose, complex, and hybrid, were present. The majority of the glycans were neutral and fucosylated; glycans featuring N-glycolylneuraminic acid and those with two galactoses connected via an α1,3-linkage were also identified.

  5. A single lysis solution for the analysis of tissue samples by different proteomic technologies

    DEFF Research Database (Denmark)

    Gromov, P.; Celis, J.E.; Gromova, I.

    2008-01-01

    -based proteomics (reverse-phase lysate arrays or direct antibody arrays), allowing the direct comparison of qualitative and quantitative data yielded by these technologies when applied to the same samples. The usefulness of the CLB1 solution for gel-based proteomics was further established by 2D PAGE analysis...... dissease, is driving scientists to increasingly use clinically relevant samples for biomarker and target discovery. Tissues are heterogeneous and as a result optimization of sample preparation is critical for generating accurate, representative, and highly reproducible quantitative data. Although a large...... number of protocols for preparation of tissue lysates has been published, so far no single recipe is able to provide a "one-size fits all" solubilization procedure that can be used to analyse the same lysate using different proteomics technologies. Here we present evidence showing that cell lysis buffer...

  6. Electron-rich anthracene semiconductors containing triarylamine for solution-processed small-molecule organic solar cells.

    Science.gov (United States)

    Choi, Hyeju; Ko, Haye Min; Cho, Nara; Song, Kihyung; Lee, Jae Kwan; Ko, Jaejung

    2012-10-01

    New electron-rich anthracene derivatives containing triarylamine hole stabilizers, 2,6-bis[5,5'-bis(N,N'-diphenylaniline)-2,2'-bithiophen-5-yl]-9,10-bis-[(triisopropylsilyl)ethynyl]anthracene (TIPSAntBT-TPA) and 2,6-bis(5,5'-bis{4-[bis(9,9-dimethyl-9H-fluoren-2-yl)amino]phenyl}-2,2'-bithiophen-5-yl)-9,10-bis-[(triisopropylsilyl)ethynyl]anthracene (TIPSAntBT-bisDMFA), linked with π-conjugated bithiophene bridges, were synthesized and their photovoltaic characteristics were investigated in solution-processed small-molecule organic solar cells (SMOSCs). These new materials exhibited superior intramolecular charge transfer from triarylamine to anthracene, leading to a more electron-rich anthracene core that facilitated electron transfer into phenyl-C(61)-butyric acid methyl ester. Compared with TIPSAntBT and triarylamine, these materials show a threefold improvement in hole-transporting properties and better photovoltaic performance in solution-processed SMOSCs, with the best power conversion efficiency being 2.96 % at a high open-circuit voltage of 0.85 V. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Solution small-angle x-ray scattering as a screening and predictive tool in the fabrication of asymmetric block copolymer membranes

    KAUST Repository

    Dorin, Rachel Mika; Marques, Debora S.; Sai, Hiroaki; Vainio, Ulla; Phillip, William A.; Peinemann, Klaus; Nunes, Suzana Pereira; Wiesner, Ulrich B.

    2012-01-01

    Small-angle X-ray scattering (SAXS) analysis of the diblock copolymer poly(styrene-b-(4-vinyl)pyridine) in a ternary solvent system of 1,4-dioxane, tetrahydrofuran, and N,N-dimethylformamide, and the triblock terpolymer poly(isoprene-b-styrene-b-(4-vinyl)-pyridine) in a binary solvent system of 1,4-dioxane and tetrahydrofuran, reveals a concentration-dependent onset of ordered structure formation. Asymmetric membranes fabricated from casting solutions with polymer concentrations at or slightly below this ordering concentration possess selective layers with the desired nanostructure. In addition to rapidly screening possible polymer solution concentrations, solution SAXS analysis also predicts hexagonal and square pore lattices of the final membrane surface structure. These results suggest solution SAXS as a powerful tool for screening casting solution concentrations and predicting surface structure in the fabrication of asymmetric ultrafiltration membranes from self-assembled block copolymers. (Figure presented) © 2012 American Chemical Society.

  8. Solution small-angle x-ray scattering as a screening and predictive tool in the fabrication of asymmetric block copolymer membranes

    KAUST Repository

    Dorin, Rachel Mika

    2012-05-15

    Small-angle X-ray scattering (SAXS) analysis of the diblock copolymer poly(styrene-b-(4-vinyl)pyridine) in a ternary solvent system of 1,4-dioxane, tetrahydrofuran, and N,N-dimethylformamide, and the triblock terpolymer poly(isoprene-b-styrene-b-(4-vinyl)-pyridine) in a binary solvent system of 1,4-dioxane and tetrahydrofuran, reveals a concentration-dependent onset of ordered structure formation. Asymmetric membranes fabricated from casting solutions with polymer concentrations at or slightly below this ordering concentration possess selective layers with the desired nanostructure. In addition to rapidly screening possible polymer solution concentrations, solution SAXS analysis also predicts hexagonal and square pore lattices of the final membrane surface structure. These results suggest solution SAXS as a powerful tool for screening casting solution concentrations and predicting surface structure in the fabrication of asymmetric ultrafiltration membranes from self-assembled block copolymers. (Figure presented) © 2012 American Chemical Society.

  9. Measurement of phthalates in small samples of mammalian tissue

    International Nuclear Information System (INIS)

    Acott, P.D.; Murphy, M.G.; Ogborn, M.R.; Crocker, J.F.S.

    1987-01-01

    Di-(2-ethylhexyl)-phthalate (DEHP) is a phthalic acid ester that is used as a plasticizer in polyvinyl chloride products, many of which have widespread medical application. DEHP has been shown to be leached from products used for storage and delivery of blood transfusions during procedures such as plasmaphoresis, hemodialysis and open heart surgery. Results of studies in this laboratory have suggested that there is an association between the absorption and deposition of DEHP (and/or related chemicals) in the kidney and the acquired renal cystic disease (ACD) frequently seen in patients who have undergone prolonged dialysis treatment. In order to determine the relationship between the two, it has been necessary to establish a method for extracting and accurately quantitating minute amounts of these chemicals in small tissue samples. The authors have now established such a method using kidneys from normal rats and from a rat model for ACD

  10. A novel approach for small sample size family-based association studies: sequential tests.

    Science.gov (United States)

    Ilk, Ozlem; Rajabli, Farid; Dungul, Dilay Ciglidag; Ozdag, Hilal; Ilk, Hakki Gokhan

    2011-08-01

    In this paper, we propose a sequential probability ratio test (SPRT) to overcome the problem of limited samples in studies related to complex genetic diseases. The results of this novel approach are compared with the ones obtained from the traditional transmission disequilibrium test (TDT) on simulated data. Although TDT classifies single-nucleotide polymorphisms (SNPs) to only two groups (SNPs associated with the disease and the others), SPRT has the flexibility of assigning SNPs to a third group, that is, those for which we do not have enough evidence and should keep sampling. It is shown that SPRT results in smaller ratios of false positives and negatives, as well as better accuracy and sensitivity values for classifying SNPs when compared with TDT. By using SPRT, data with small sample size become usable for an accurate association analysis.

  11. Equipment for collecting samples of radioactive solutions

    International Nuclear Information System (INIS)

    Raggenbass, A.; Fradin, J.; Joubert, G.

    1958-01-01

    The authors present an equipment aimed at collecting samples of fission products to perform radio-chemical analysis. As the sample must have a total activity between 1 and 50 micro-Curie, this installation comprises a sampling system and a dilution device which aims at bringing the sample to the suitable activity. Samples are collected by means of needles. The sample reproducibility is discussed. The dilution device is described

  12. TF4SM: A Framework for Developing Traceability Solutions in Small Manufacturing Companies

    Science.gov (United States)

    Bordel Sánchez, Borja; Alcarria, Ramón; Martín, Diego; Robles, Tomás

    2015-01-01

    Nowadays, manufacturing processes have become highly complex. Besides, more and more, governmental institutions require companies to implement systems to trace a product’s life (especially for foods, clinical materials or similar items). In this paper, we propose a new framework, based on cyber-physical systems, for developing traceability systems in small manufacturing companies (which because of their size cannot implement other commercial products). We propose a general theoretical framework, study the requirements of these companies in relation to traceability systems, propose a reference architecture based on both previous elements and build the first minimum functional prototype, to compare our solution to a traditional tag-based traceability system. Results show that our system reduces the number of inefficiencies and reaction time. PMID:26610509

  13. Analysis of the aggregation structure from amphiphilic block copolymers in solutions by small-angle x-ray scattering

    CERN Document Server

    Rong Li Xia; Wang Jun; Wei Liu He; Li Fu Mian; Li Zi Chen

    2002-01-01

    The aggregation structure of polystyrene-p vinyl benzoic amphiphilic block copolymers which were prepared in different conditions was investigated by synchrotron radiation small-angle x-ray scattering (SAXS). The micelle was self-assembled in selective solvents of the block copolymers. Authors' results demonstrate that the structure of the micelle depends on the factors, such as the composition of the copolymers, the nature of the solvent and the concentration of the solution

  14. Report of the advisory group meeting on elemental analysis of extremely small samples

    International Nuclear Information System (INIS)

    2002-01-01

    This publication contains summary of discussions held at the meeting with brief description and comparative characteristics of most common nuclear analytical techniques used for analysis of very small samples as well as the conclusions of the meeting. Some aspect of reference materials and quality control are also discussed. The publication also contains individual contributions made by the participants, each of these papers haven provided with an abstract and indexed separately

  15. Planetary Sample Caching System Design Options

    Science.gov (United States)

    Collins, Curtis; Younse, Paulo; Backes, Paul

    2009-01-01

    Potential Mars Sample Return missions would aspire to collect small core and regolith samples using a rover with a sample acquisition tool and sample caching system. Samples would need to be stored in individual sealed tubes in a canister that could be transfered to a Mars ascent vehicle and returned to Earth. A sample handling, encapsulation and containerization system (SHEC) has been developed as part of an integrated system for acquiring and storing core samples for application to future potential MSR and other potential sample return missions. Requirements and design options for the SHEC system were studied and a recommended design concept developed. Two families of solutions were explored: 1)transfer of a raw sample from the tool to the SHEC subsystem and 2)transfer of a tube containing the sample to the SHEC subsystem. The recommended design utilizes sample tool bit change out as the mechanism for transferring tubes to and samples in tubes from the tool. The SHEC subsystem design, called the Bit Changeout Caching(BiCC) design, is intended for operations on a MER class rover.

  16. Uncertainty of solute flux estimation in ungauged small streams: potential implications for input-output nutrient mass balances at stream reach scale

    Directory of Open Access Journals (Sweden)

    A. Butturini

    2005-01-01

    Full Text Available Input-output mass balances within stream reaches provide in situ estimates of stream nutrient retention/release under a wide spectrum of hydrological conditions. Providing good estimates of the mass balances for nutrients depends on precise hydrological monitoring and good chemical characterisation of stream water at the input and output ends of the stream reach. There is a need to optimise the hydrological monitoring and the frequencies of water sampling to yield precise annual mass balances, so as to avoid undue cost - high resolution monitoring and subsequent chemical analysis can be labour intensive and costly. In this paper, simulation exercises were performed using a data set created to represent the instantaneous discharge and solute dynamics at the input and output ends of a model stream reach during a one year period. At the output end, stream discharge and water chemistry were monitored continuously, while the input end was assumed to be ungauged; water sampling frequency was changed arbitrarily. Instantaneous discharge at the ungauged sampling point was estimated with an empirical power model linking the discharge to the catchment area (Hooper, 1986. The model thus substitutes for the additional gauge station. Simulations showed that 10 days was the longest chemical sampling interval which could provide reach annual mass balances of acceptable precision. Presently, the relationship between discharge and catchment area is usually assumed to be linear but simulations indicate that small departures from the linearity of this relationship could cause dramatic changes in the mass balance estimations.

  17. Evaluation applications of instrument calibration research findings in psychology for very small samples

    Science.gov (United States)

    Fisher, W. P., Jr.; Petry, P.

    2016-11-01

    Many published research studies document item calibration invariance across samples using Rasch's probabilistic models for measurement. A new approach to outcomes evaluation for very small samples was employed for two workshop series focused on stress reduction and joyful living conducted for health system employees and caregivers since 2012. Rasch-calibrated self-report instruments measuring depression, anxiety and stress, and the joyful living effects of mindfulness behaviors were identified in peer-reviewed journal articles. Items from one instrument were modified for use with a US population, other items were simplified, and some new items were written. Participants provided ratings of their depression, anxiety and stress, and the effects of their mindfulness behaviors before and after each workshop series. The numbers of participants providing both pre- and post-workshop data were low (16 and 14). Analysis of these small data sets produce results showing that, with some exceptions, the item hierarchies defining the constructs retained the same invariant profiles they had exhibited in the published research (correlations (not disattenuated) range from 0.85 to 0.96). In addition, comparisons of the pre- and post-workshop measures for the three constructs showed substantively and statistically significant changes. Implications for program evaluation comparisons, quality improvement efforts, and the organization of communications concerning outcomes in clinical fields are explored.

  18. Asymptotic solutions of steady magneto-fluid-dynamic motion between two rotating disks with a small gap

    International Nuclear Information System (INIS)

    Xu, J.J.; Woo, J.T.

    1987-01-01

    The steady-state flow of a conducting fluid between two coaxial rotating disks in the presence of an axial magnetic field is considered for the following conditions: (1) the gap d between two disks is very small compared with the radial extension of the disks R; (2) the angular velocity of the disks is not too high, so that the thickness of the Eckman layer δ is still larger than the gap d, (d/δ) 1 /sup // 4 2 /d 2 . Under these conditions asymptotic solutions to the problem are obtained in terms of the small parameter Epsilon = d/R. The results show that to the lowest-order approximation, the electric properties of the disks are not important to the flow field, while the magnitude of the magnetic field plays an important role in the equilibrium flow profile

  19. Electro chemical studies on stress corrosion cracking of Incoloy-800 in caustic solution, part I: As received samples

    Directory of Open Access Journals (Sweden)

    Dinu Alice

    2005-01-01

    Full Text Available Many non-volatile impurities accidentally introduced into the steam generator tend to Concentrate on its surface in restricted flow areas. In this way these impurities can lead to stress corrosion cracking (SCC on stressed tubes of the steam generator. Such impurities can be strong alkaline or acid solutions. To evaluate the effect of alkaline concentrated environments on SCC of steam generator tubes, the tests were con ducted on stressed samples of Incoloy-800 in 10% NaOH solution. To accelerate the SCC process, stressed specimens were anodically polarised in a caustic solution in an electro chemical cell. The method of stressing of Incoloy-800 tubes used in our experiments was the C-ring. Using the cathodic zone of the potentiodynamic curves it was possible to calculate the most important electrochemical parameters: the corrosion current, the corrosion rate, and the polarization resistance. We found that the value of the corrosion potential to initiate the SCC microcracks was -100 mV. The tested samples were examined using the metallographic method. The main experimental results showed that the in crease of the stress state promoted the in crease of the SCC susceptibility of Incoloy-800 samples tested under the same conditions, and that the length of the SCC-type microcracks in creased with the growth of the stress value.

  20. Accounting for thermodynamic non-ideality in the Guinier region of small-angle scattering data of proteins.

    Science.gov (United States)

    Scott, David J

    2016-12-01

    Hydrodynamic studies of the solution properties of proteins and other biological macromolecules are often hard to interpret when the sample is present at a reasonably concentrated solution. The reason for this is that solutions exhibit deviations from ideal behaviour which is manifested as thermodynamic non-ideality. The range of concentrations at which this behaviour typically is exhibited is as low as 1-2 mg/ml, well within the range of concentrations used for their analysis by techniques such as small-angle scattering. Here we discuss thermodynamic non-ideality used previously used in the context of light scattering and sedimentation equilibrium analytical ultracentrifugation and apply it to the Guinier region of small-angle scattering data. The results show that there is a complementarity between the radially averaged structure factor derived from small-angle X-ray scattering/small-angle neutron scattering studies and the second virial coefficient derived from sedimentation equilibrium analytical ultracentrifugation experiments.

  1. Mass amplifying probe for sensitive fluorescence anisotropy detection of small molecules in complex biological samples.

    Science.gov (United States)

    Cui, Liang; Zou, Yuan; Lin, Ninghang; Zhu, Zhi; Jenkins, Gareth; Yang, Chaoyong James

    2012-07-03

    Fluorescence anisotropy (FA) is a reliable and excellent choice for fluorescence sensing. One of the key factors influencing the FA value for any molecule is the molar mass of the molecule being measured. As a result, the FA method with functional nucleic acid aptamers has been limited to macromolecules such as proteins and is generally not applicable for the analysis of small molecules because their molecular masses are relatively too small to produce observable FA value changes. We report here a molecular mass amplifying strategy to construct anisotropy aptamer probes for small molecules. The probe is designed in such a way that only when a target molecule binds to the probe does it activate its binding ability to an anisotropy amplifier (a high molecular mass molecule such as protein), thus significantly increasing the molecular mass and FA value of the probe/target complex. Specifically, a mass amplifying probe (MAP) consists of a targeting aptamer domain against a target molecule and molecular mass amplifying aptamer domain for the amplifier protein. The probe is initially rendered inactive by a small blocking strand partially complementary to both target aptamer and amplifier protein aptamer so that the mass amplifying aptamer domain would not bind to the amplifier protein unless the probe has been activated by the target. In this way, we prepared two probes that constitute a target (ATP and cocaine respectively) aptamer, a thrombin (as the mass amplifier) aptamer, and a fluorophore. Both probes worked well against their corresponding small molecule targets, and the detection limits for ATP and cocaine were 0.5 μM and 0.8 μM, respectively. More importantly, because FA is less affected by environmental interferences, ATP in cell media and cocaine in urine were directly detected without any tedious sample pretreatment. Our results established that our molecular mass amplifying strategy can be used to design aptamer probes for rapid, sensitive, and selective

  2. 40 CFR Appendix A to Subpart F of... - Sampling Plans for Selective Enforcement Auditing of Small Nonroad Engines

    Science.gov (United States)

    2010-07-01

    ... Enforcement Auditing of Small Nonroad Engines A Appendix A to Subpart F of Part 90 Protection of Environment...-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Selective Enforcement Auditing Pt. 90, Subpt. F, App. A Appendix A to Subpart F of Part 90—Sampling Plans for Selective Enforcement Auditing of Small Nonroad Engines...

  3. [Monitoring microbiological safety of small systems of water distribution. Comparison of two sampling programs in a town in central Italy].

    Science.gov (United States)

    Papini, Paolo; Faustini, Annunziata; Manganello, Rosa; Borzacchi, Giancarlo; Spera, Domenico; Perucci, Carlo A

    2005-01-01

    To determine the frequency of sampling in small water distribution systems (distribution. We carried out two sampling programs to monitor the water distribution system in a town in Central Italy between July and September 1992; the Poisson distribution assumption implied 4 water samples, the assumption of negative binomial distribution implied 21 samples. Coliform organisms were used as indicators of water safety. The network consisted of two pipe rings and two wells fed by the same water source. The number of summer customers varied considerably from 3,000 to 20,000. The mean density was 2.33 coliforms/100 ml (sd= 5.29) for 21 samples and 3 coliforms/100 ml (sd= 6) for four samples. However the hypothesis of homogeneity was rejected (p-value samples (beta= 0.24) than with 21 (beta= 0.05). For this small network, determining the samples' size according to heterogeneity hypothesis strengthens the statement that water is drinkable compared with homogeneity assumption.

  4. Stability of small-amplitude periodic solutions near Hopf bifurcations in time-delayed fully-connected PLL networks

    Science.gov (United States)

    Ferruzzo Correa, Diego P.; Bueno, Átila M.; Castilho Piqueira, José R.

    2017-04-01

    In this paper we investigate stability conditions for small-amplitude periodic solutions emerging near symmetry-preserving Hopf bifurcations in a time-delayed fully-connected N-node PLL network. The study of this type of systems which includes the time delay between connections has attracted much attention among researchers mainly because the delayed coupling between nodes emerges almost naturally in mathematical modeling in many areas of science such as neurobiology, population dynamics, physiology and engineering. In a previous work it has been shown that symmetry breaking and symmetry preserving Hopf bifurcations can emerge in the parameter space. We analyze the stability along branches of periodic solutions near fully-synchronized Hopf bifurcations in the fixed-point space, based on the reduction of the infinite-dimensional space onto a two-dimensional center manifold in normal form. Numerical results are also presented in order to confirm our analytical results.

  5. Sensitive power compensated scanning calorimeter for analysis of phase transformations in small samples

    International Nuclear Information System (INIS)

    Lopeandia, A.F.; Cerdo, Ll.; Clavaguera-Mora, M.T.; Arana, Leonel R.; Jensen, K.F.; Munoz, F.J.; Rodriguez-Viejo, J.

    2005-01-01

    We have designed and developed a sensitive scanning calorimeter for use with microgram or submicrogram, thin film, or powder samples. Semiconductor processing techniques are used to fabricate membrane based microreactors with a small heat capacity of the addenda, 120 nJ/K at room temperature. At heating rates below 10 K/s the heat released or absorbed by the sample during a given transformation is compensated through a resistive Pt heater by a digital controller so that the calorimeter works as a power compensated device. Its use and dynamic sensitivity is demonstrated by analyzing the melting behavior of thin films of indium and high density polyethylene. Melting enthalpies in the range of 40-250 μJ for sample masses on the order of 1.5 μg have been measured with accuracy better than 5% at heating rates ∼0.2 K/s. The signal-to-noise ratio, limited by the electronic setup, is 200 nW

  6. So you've got your sample in solution. What next? (W7)

    International Nuclear Information System (INIS)

    Brindle, I.P.

    2002-01-01

    Full text: Several factors must be considered after the sample is prepared for analysis. These factors include memory, oxidation state of analyte, presence of interfering elements, etc. Some elements are 'sticky' and exhibit prodigious memory effects. For elements like mercury, gold and boron, memory effects make it difficult to determine elemental concentrations in samples that vary widely in concentration. When selenium is determined by hydride generation, the selenium cannot be in the VI oxidation state, since borohydride will not reduce this oxidation state. Different treatments must be used. The treatment of organometallics may require, in addition, the presence of reagents to improve the yield of derivitized species that are to be determined. Interfering elements must sometimes be masked or removed before determination of the analyte can proceed. In this presentation, these various issues will be discussed. Solutions to some of the problems, from the analytical chemistry laboratories at Brock University, will be presented. In addition, options for the simultaneous determination of elements by vapor generation and nebulization will be discussed, based on recent work in the Brock laboratories. (author)

  7. 2017 publication guidelines for structural modelling of small-angle scattering data from biomolecules in solution: an update.

    Science.gov (United States)

    Trewhella, Jill; Duff, Anthony P; Durand, Dominique; Gabel, Frank; Guss, J Mitchell; Hendrickson, Wayne A; Hura, Greg L; Jacques, David A; Kirby, Nigel M; Kwan, Ann H; Pérez, Javier; Pollack, Lois; Ryan, Timothy M; Sali, Andrej; Schneidman-Duhovny, Dina; Schwede, Torsten; Svergun, Dmitri I; Sugiyama, Masaaki; Tainer, John A; Vachette, Patrice; Westbrook, John; Whitten, Andrew E

    2017-09-01

    In 2012, preliminary guidelines were published addressing sample quality, data acquisition and reduction, presentation of scattering data and validation, and modelling for biomolecular small-angle scattering (SAS) experiments. Biomolecular SAS has since continued to grow and authors have increasingly adopted the preliminary guidelines. In parallel, integrative/hybrid determination of biomolecular structures is a rapidly growing field that is expanding the scope of structural biology. For SAS to contribute maximally to this field, it is essential to ensure open access to the information required for evaluation of the quality of SAS samples and data, as well as the validity of SAS-based structural models. To this end, the preliminary guidelines for data presentation in a publication are reviewed and updated, and the deposition of data and associated models in a public archive is recommended. These guidelines and recommendations have been prepared in consultation with the members of the International Union of Crystallography (IUCr) Small-Angle Scattering and Journals Commissions, the Worldwide Protein Data Bank (wwPDB) Small-Angle Scattering Validation Task Force and additional experts in the field.

  8. An investigation of calibration methods for solution calorimetry.

    Science.gov (United States)

    Yff, Barbara T S; Royall, Paul G; Brown, Marc B; Martin, Gary P

    2004-01-28

    Solution calorimetry has been used in a number of varying applications within pharmaceutical research as a technique for the physical characterisation of pharmaceutical materials, such as quantifying small degrees of amorphous content, identifying polymorphs and investigating interactions between drugs and carbohydrates or proteins and carbohydrates. A calibration test procedure is necessary to validate the instrumentation; a few of the suggested calibration reactions are the enthalpies of solution associated with dissolving Tris in 0.1 M HCl or NaCl, KCl or propan-1-ol in water. In addition, there are a number of different methods available to determine enthalpies of solution from the experimental data provided by the calorimeter, for example, the Regnault-Pfaundler's method, a graphical extrapolation based on the Dickinson method, or a manual integration-based method. Thus, the aim of the study was to investigate how each of these methods influences the values for the enthalpy of solution. Experiments were performed according to the method outlined by Hogan and Buckton [Int. J. Pharm. 207 (2000) 57] using KCl (samples of 50, 100 and 200 mg), Tris and sucrose as calibrants. For all three materials the manual integration method was found to be the most consistent with the KCl in water (sample mass of 200 mg) being the most precise. Thus, this method is recommended for the validation of solution calorimeters.

  9. Software-as-a-Service and Cloud Computing, a solution for small and medium-sized companies

    Directory of Open Access Journals (Sweden)

    Bajenaru, A.

    2010-12-01

    Full Text Available Small and medium-sized companies are an important part of today’s world economy, for their ability to offer new jobs but also for their capacity of innovation. At the same time, they are in a constant struggle with larger companies that take advantage of their negotiating power to impose their way of doing business to the SMEs. In an ICT enabled world, most large companies being intense ICT users, the lag of ICT adoption in SMEs may create a strong barrier between SMEs and large companies, promoting an over growing digital divide, the SMEs being in danger of being left out in some economic sectors. This paper aims at finding a possible solution in the Software-as-a-Service and Cloud Computing model, a rather new solution, yet more and more sought off by SMEs but also larger companies, especially considering the global financial and economic crisis, as well as evaluating the European Union’s main views and policies regarding the SAAS – Cloud model.

  10. Solution-Processed Small-Molecule Bulk Heterojunctions: Leakage Currents and the Dewetting Issue for Inverted Solar Cells.

    Science.gov (United States)

    Destouesse, Elodie; Chambon, Sylvain; Courtel, Stéphanie; Hirsch, Lionel; Wantz, Guillaume

    2015-11-11

    In organic photovoltaic (PV) devices based on solution-processed small molecules, we report here that the physicochemical properties of the substrate are critical for achieving high-performances organic solar cells. Three different substrates were tested: ITO coated with PSS, ZnO sol-gel, and ZnO nanoparticles. PV performances are found to be low when the ZnO nanoparticles layer is used. This performance loss is attributed to the formation of many dewetting points in the active layer, because of a relatively high roughness of the ZnO nanoparticles layer, compared to the other layers. We successfully circumvented this phenomenon by adding a small quantity of polystyrene (PS) in the active layer. The introduction of PS improves the quality of film forming and reduces the dark currents of solar cells. Using this method, high-efficiency devices were achieved, even in the case of substrates with higher roughness.

  11. Effective interactions in lysozyme aqueous solutions: a small-angle neutron scattering and computer simulation study.

    Science.gov (United States)

    Abramo, M C; Caccamo, C; Costa, D; Pellicane, G; Ruberto, R; Wanderlingh, U

    2012-01-21

    We report protein-protein structure factors of aqueous lysozyme solutions at different pH and ionic strengths, as determined by small-angle neutron scattering experiments. The observed upturn of the structure factor at small wavevectors, as the pH increases, marks a crossover between two different regimes, one dominated by repulsive forces, and another one where attractive interactions become prominent, with the ensuing development of enhanced density fluctuations. In order to rationalize such experimental outcome from a microscopic viewpoint, we have carried out extensive simulations of different coarse-grained models. We have first studied a model in which macromolecules are described as soft spheres interacting through an attractive r(-6) potential, plus embedded pH-dependent discrete charges; we show that the uprise undergone by the structure factor is qualitatively predicted. We have then studied a Derjaguin-Landau-Verwey-Overbeek (DLVO) model, in which only central interactions are advocated; we demonstrate that this model leads to a protein-rich/protein-poor coexistence curve that agrees quite well with the experimental counterpart; experimental correlations are instead reproduced only at low pH and ionic strengths. We have finally investigated a third, "mixed" model in which the central attractive term of the DLVO potential is imported within the distributed-charge approach; it turns out that the different balance of interactions, with a much shorter-range attractive contribution, leads in this latter case to an improved agreement with the experimental crossover. We discuss the relationship between experimental correlations, phase coexistence, and features of effective interactions, as well as possible paths toward a quantitative prediction of structural properties of real lysozyme solutions. © 2012 American Institute of Physics

  12. Communication: Newton homotopies for sampling stationary points of potential energy landscapes

    Energy Technology Data Exchange (ETDEWEB)

    Mehta, Dhagash, E-mail: dmehta@nd.edu [Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, Indiana 46556 (United States); University Chemical Laboratory, The University of Cambridge, Cambridge CB2 1EW (United Kingdom); Chen, Tianran, E-mail: chentia1@msu.edu [Department of Mathematics, Michigan State University, East Lansing, Michigan 48823 (United States); Hauenstein, Jonathan D., E-mail: hauenstein@nd.edu [Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Wales, David J., E-mail: dw34@cam.ac.uk [University Chemical Laboratory, The University of Cambridge, Cambridge CB2 1EW (United Kingdom)

    2014-09-28

    One of the most challenging and frequently arising problems in many areas of science is to find solutions of a system of multivariate nonlinear equations. There are several numerical methods that can find many (or all if the system is small enough) solutions but they all exhibit characteristic problems. Moreover, traditional methods can break down if the system contains singular solutions. Here, we propose an efficient implementation of Newton homotopies, which can sample a large number of the stationary points of complicated many-body potentials. We demonstrate how the procedure works by applying it to the nearest-neighbor ϕ{sup 4} model and atomic clusters.

  13. Communication: Newton homotopies for sampling stationary points of potential energy landscapes

    International Nuclear Information System (INIS)

    Mehta, Dhagash; Chen, Tianran; Hauenstein, Jonathan D.; Wales, David J.

    2014-01-01

    One of the most challenging and frequently arising problems in many areas of science is to find solutions of a system of multivariate nonlinear equations. There are several numerical methods that can find many (or all if the system is small enough) solutions but they all exhibit characteristic problems. Moreover, traditional methods can break down if the system contains singular solutions. Here, we propose an efficient implementation of Newton homotopies, which can sample a large number of the stationary points of complicated many-body potentials. We demonstrate how the procedure works by applying it to the nearest-neighbor ϕ 4 model and atomic clusters

  14. Evaluating the biological potential in samples returned from planetary satellites and small solar system bodies: framework for decision making

    National Research Council Canada - National Science Library

    National Research Council Staff; Space Studies Board; Division on Engineering and Physical Sciences; National Research Council; National Academy of Sciences

    ... from Planetary Satellites and Small Solar System Bodies Framework for Decision Making Task Group on Sample Return from Small Solar System Bodies Space Studies Board Commission on Physical Sciences, Mathematics, and Applications National Research Council NATIONAL ACADEMY PRESS Washington, D.C. 1998 i Copyrightthe true use are Please breaks...

  15. Biological Small Angle Scattering: Techniques, Strategies and Tips

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhuri, Barnali [University at Buffalo (SUNY); Muñoz, Inés G. [Centro Nacional de Investigaciones Oncológicas Madrid, Madrid, Spain; Urban, Volker S. [ORNL; Qian, Shuo [ORNL

    2017-12-01

    This book provides a clear, comprehensible and up-to-date description of how Small Angle Scattering (SAS) can help structural biology researchers. SAS is an efficient technique that offers structural information on how biological macromolecules behave in solution. SAS provides distinct and complementary data for integrative structural biology approaches in combination with other widely used probes, such as X-ray crystallography, Nuclear magnetic resonance, Mass spectrometry and Cryo-electron Microscopy. The development of brilliant synchrotron small-angle X-ray scattering (SAXS) beam lines has increased the number of researchers interested in solution scattering. SAS is especially useful for studying conformational changes in proteins, highly flexible proteins, and intrinsically disordered proteins. Small-angle neutron scattering (SANS) with neutron contrast variation is ideally suited for studying multi-component assemblies as well as membrane proteins that are stabilized in surfactant micelles or vesicles. SAS is also used for studying dynamic processes of protein fibrillation in amyloid diseases, and pharmaceutical drug delivery. The combination with size-exclusion chromatography further increases the range of SAS applications.The book is written by leading experts in solution SAS methodologies. The principles and theoretical background of various SAS techniques are included, along with practical aspects that range from sample preparation to data presentation for publication. Topics covered include techniques for improving data quality and analysis, as well as different scientific applications of SAS. With abundant illustrations and practical tips, we hope the clear explanations of the principles and the reviews on the latest progresses will serve as a guide through all aspects of biological solution SAS.The scope of this book is particularly relevant for structural biology researchers who are new to SAS. Advanced users of the technique will find it helpful for

  16. A simple Bayesian approach to quantifying confidence level of adverse event incidence proportion in small samples.

    Science.gov (United States)

    Liu, Fang

    2016-01-01

    In both clinical development and post-marketing of a new therapy or a new treatment, incidence of an adverse event (AE) is always a concern. When sample sizes are small, large sample-based inferential approaches on an AE incidence proportion in a certain time period no longer apply. In this brief discussion, we introduce a simple Bayesian framework to quantify, in small sample studies and the rare AE case, (1) the confidence level that the incidence proportion of a particular AE p is over or below a threshold, (2) the lower or upper bounds on p with a certain level of confidence, and (3) the minimum required number of patients with an AE before we can be certain that p surpasses a specific threshold, or the maximum allowable number of patients with an AE after which we can no longer be certain that p is below a certain threshold, given a certain confidence level. The method is easy to understand and implement; the interpretation of the results is intuitive. This article also demonstrates the usefulness of simple Bayesian concepts when it comes to answering practical questions.

  17. Small Sample Reactivity Measurements in the RRR/SEG Facility: Reanalysis using TRIPOLI-4

    Energy Technology Data Exchange (ETDEWEB)

    Hummel, Andrew [Idaho National Lab. (INL), Idaho Falls, ID (United States); Palmiotti, Guiseppe [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-08-01

    This work involved reanalyzing the RRR/SEG integral experiments performed at the Rossendorf facility in Germany throughout the 1970s and 80s. These small sample reactivity worth measurements were carried out using the pile oscillator technique for many different fission products, structural materials, and standards. The coupled fast-thermal system was designed such that the measurements would provide insight into elemental data, specifically the competing effects between neutron capture and scatter. Comparing the measured to calculated reactivity values can then provide adjustment criteria to ultimately improve nuclear data for fast reactor designs. Due to the extremely small reactivity effects measured (typically less than 1 pcm) and the specific heterogeneity of the core, the tool chosen for this analysis was TRIPOLI-4. This code allows for high fidelity 3-dimensional geometric modeling, and the most recent, unreleased version, is capable of exact perturbation theory.

  18. Improvement of 137Cs analysis in small volume seawater samples using the Ogoya underground facility

    International Nuclear Information System (INIS)

    Hirose, K.; Komura, K.; Kanazawa University, Ishikawa; Aoyama, M.; Igarashi, Y.

    2008-01-01

    137 Cs in seawater is one of the most powerful tracers of water motion. Large volumes of samples have been required for determination of 137 Cs in seawater. This paper describes improvement of separation and purification processes of 137 Cs in seawater, which includes purification of 137 Cs using hexachloroplatinic acid in addition to ammonium phosphomolybdate (AMP) precipitation. As a result, we succeeded the 137 Cs determination in seawater with a smaller sample volume of 10 liter by using ultra-low background gamma-spectrometry in the Ogoya underground facility. 137 Cs detection limit was about 0.1 mBq (counting time: 10 6 s). This method is applied to determine 137 Cs in small samples of the South Pacific deep waters. (author)

  19. The small sample uncertainty aspect in relation to bullwhip effect measurement

    DEFF Research Database (Denmark)

    Nielsen, Erland Hejn

    2009-01-01

    The bullwhip effect as a concept has been known for almost half a century starting with the Forrester effect. The bullwhip effect is observed in many supply chains, and it is generally accepted as a potential malice. Despite of this fact, the bullwhip effect still seems to be first and foremost...... a conceptual phenomenon. This paper intends primarily to investigate why this might be so and thereby investigate the various aspects, possibilities and obstacles that must be taken into account, when considering the potential practical use and measure of the bullwhip effect in order to actually get the supply...... chain under control. This paper will put special emphasis on the unavoidable small-sample uncertainty aspects relating to the measurement or estimation of the bullwhip effect.  ...

  20. Sampling Error in Relation to Cyst Nematode Population Density Estimation in Small Field Plots.

    Science.gov (United States)

    Župunski, Vesna; Jevtić, Radivoje; Jokić, Vesna Spasić; Župunski, Ljubica; Lalošević, Mirjana; Ćirić, Mihajlo; Ćurčić, Živko

    2017-06-01

    Cyst nematodes are serious plant-parasitic pests which could cause severe yield losses and extensive damage. Since there is still very little information about error of population density estimation in small field plots, this study contributes to the broad issue of population density assessment. It was shown that there was no significant difference between cyst counts of five or seven bulk samples taken per each 1-m 2 plot, if average cyst count per examined plot exceeds 75 cysts per 100 g of soil. Goodness of fit of data to probability distribution tested with χ 2 test confirmed a negative binomial distribution of cyst counts for 21 out of 23 plots. The recommended measure of sampling precision of 17% expressed through coefficient of variation ( cv ) was achieved if the plots of 1 m 2 contaminated with more than 90 cysts per 100 g of soil were sampled with 10-core bulk samples taken in five repetitions. If plots were contaminated with less than 75 cysts per 100 g of soil, 10-core bulk samples taken in seven repetitions gave cv higher than 23%. This study indicates that more attention should be paid on estimation of sampling error in experimental field plots to ensure more reliable estimation of population density of cyst nematodes.

  1. Results For The Third Quarter Calendar Year 2016 Tank 50H Salt Solution Sample

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-10-13

    In this memorandum, the chemical and radionuclide contaminant results from the Third Quarter Calendar Year 2016 (CY16) sample of Tank 50H salt solution are presented in tabulated form. The Third Quarter CY16 Tank 50H samples (a 200 mL sample obtained 6” below the surface (HTF-5-16-63) and a 1 L sample obtained 66” from the tank bottom (HTF-50-16-64)) were obtained on July 14, 2016 and received at Savannah River National Laboratory (SRNL) on the same day. Prior to obtaining the samples from Tank 50H, a single pump was run at least 4.4 hours, and the samples were pulled immediately after pump shut down. The information from this characterization will be used by Defense Waste Processing Facility (DWPF) & Saltstone Facility Engineering for the transfer of aqueous waste from Tank 50H to the Saltstone Production Facility, where the waste will be treated and disposed of in the Saltstone Disposal Facility. This memorandum compares results, where applicable, to Saltstone Waste Acceptance Criteria (WAC) limits and targets. Data pertaining to the regulatory limits for Resource Conservation and Recovery Act (RCRA) metals will be documented at a later time per the Task Technical and Quality Assurance Plan (TTQAP) for the Tank 50H saltstone task. The chemical and radionuclide contaminant results from the characterization of the Third Quarter CY16 sampling of Tank 50H were requested by Savannah River Remediation (SRR) personnel and details of the testing are presented in the SRNL TTQAP.

  2. Fast micro Hall effect measurements on small pads

    DEFF Research Database (Denmark)

    Østerberg, Frederik Westergaard; Petersen, Dirch Hjorth; Nielsen, Peter F.

    2011-01-01

    Sheet resistance, carrier mobility, and sheet carrier density are important parameters in semiconductor production, and it is therefore important to be able to rapidly and accurately measure these parameters even on small samples or pads. The interpretation of four-point probe measurements on small...... pads is non-trivial. In this paper we discuss how conformal mapping can be used to evaluate theoretically expected measurement values on small pads. Theoretical values calculated from analytical mappings of simple geometries are compared to the values found from the numerical conformal mapping...... of a square onto the infinite half-plane, where well-established solutions are known. Hall effect measurements are performed to show, experimentally, that it is possible to measure Hall mobility in less than one minute on squares as small as 7070 lm2 with a deviation of 66.5% on a 1r level from accurate...

  3. Impact of the electron-transport layer on the performance of solution-processed small-molecule organic solar cells.

    Science.gov (United States)

    Long, Guankui; Wan, Xiangjian; Kan, Bin; Hu, Zhicheng; Yang, Xuan; Zhang, Yi; Zhang, Mingtao; Wu, Hongbing; Huang, Fei; Su, Shijian; Cao, Yong; Chen, Yongsheng

    2014-08-01

    Although the performance of polymer solar cells has been improved significantly recently through careful optimization with different interlayers for the same materials, more improvement is needed in this respect for small-molecule-based solar cells, particularly for the electron-transport layers (ETLs). In this work, three different solution-processed ETLs, PFN, ZnO nanoparticles, and LiF, were investigated and compared in the performance of small-molecule-based devices, and power conversion efficiencies (PCEs) of 8.32, 7.30, and 7.38% were achieved, respectively. The mechanism for the ETL-induced enhancement has been studied, and different ETLs have a significantly different impact on the device performance. The clearly improved performance of PFN is attributed to the combination of reduced bimolecular recombination and increased effective photon absorption in the active layer. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Assessing pesticide concentrations and fluxes in the stream of a small vineyard catchment - Effect of sampling frequency

    International Nuclear Information System (INIS)

    Rabiet, M.; Margoum, C.; Gouy, V.; Carluer, N.; Coquery, M.

    2010-01-01

    This study reports on the occurrence and behaviour of six pesticides and one metabolite in a small stream draining a vineyard catchment. Base flow and flood events were monitored in order to assess the variability of pesticide concentrations according to the season and to evaluate the role of sampling frequency on the evaluation of fluxes estimates. Results showed that dissolved pesticide concentrations displayed a strong temporal and spatial variability. A large mobilisation of pesticides was observed during floods, with total dissolved pesticide fluxes per event ranging from 5.7 x 10 -3 g/Ha to 0.34 g/Ha. These results highlight the major role of floods in the transport of pesticides in this small stream which contributed to more than 89% of the total load of diuron during August 2007. The evaluation of pesticide loads using different sampling strategies and method calculation, showed that grab sampling largely underestimated pesticide concentrations and fluxes transiting through the stream. - This work brings new insights about the fluxes of pesticides in surface water of a vineyard catchment, notably during flood events.

  5. Assessing pesticide concentrations and fluxes in the stream of a small vineyard catchment - Effect of sampling frequency

    Energy Technology Data Exchange (ETDEWEB)

    Rabiet, M., E-mail: marion.rabiet@unilim.f [Cemagref, UR QELY, 3bis quai Chauveau, CP 220, F-69336 Lyon (France); Margoum, C.; Gouy, V.; Carluer, N.; Coquery, M. [Cemagref, UR QELY, 3bis quai Chauveau, CP 220, F-69336 Lyon (France)

    2010-03-15

    This study reports on the occurrence and behaviour of six pesticides and one metabolite in a small stream draining a vineyard catchment. Base flow and flood events were monitored in order to assess the variability of pesticide concentrations according to the season and to evaluate the role of sampling frequency on the evaluation of fluxes estimates. Results showed that dissolved pesticide concentrations displayed a strong temporal and spatial variability. A large mobilisation of pesticides was observed during floods, with total dissolved pesticide fluxes per event ranging from 5.7 x 10{sup -3} g/Ha to 0.34 g/Ha. These results highlight the major role of floods in the transport of pesticides in this small stream which contributed to more than 89% of the total load of diuron during August 2007. The evaluation of pesticide loads using different sampling strategies and method calculation, showed that grab sampling largely underestimated pesticide concentrations and fluxes transiting through the stream. - This work brings new insights about the fluxes of pesticides in surface water of a vineyard catchment, notably during flood events.

  6. Simultaneous small-sample comparisons in longitudinal or multi-endpoint trials using multiple marginal models

    DEFF Research Database (Denmark)

    Pallmann, Philip; Ritz, Christian; Hothorn, Ludwig A

    2018-01-01

    , however only asymptotically. In this paper, we show how to make the approach also applicable to small-sample data problems. Specifically, we discuss the computation of adjusted P values and simultaneous confidence bounds for comparisons of randomised treatment groups as well as for levels......Simultaneous inference in longitudinal, repeated-measures, and multi-endpoint designs can be onerous, especially when trying to find a reasonable joint model from which the interesting effects and covariances are estimated. A novel statistical approach known as multiple marginal models greatly...... simplifies the modelling process: the core idea is to "marginalise" the problem and fit multiple small models to different portions of the data, and then estimate the overall covariance matrix in a subsequent, separate step. Using these estimates guarantees strong control of the family-wise error rate...

  7. Automated microfluidic sample-preparation platform for high-throughput structural investigation of proteins by small-angle X-ray scattering

    DEFF Research Database (Denmark)

    Lafleur, Josiane P.; Snakenborg, Detlef; Nielsen, Søren Skou

    2011-01-01

    A new microfluidic sample-preparation system is presented for the structural investigation of proteins using small-angle X-ray scattering (SAXS) at synchrotrons. The system includes hardware and software features for precise fluidic control, sample mixing by diffusion, automated X-ray exposure...... control, UV absorbance measurements and automated data analysis. As little as 15 l of sample is required to perform a complete analysis cycle, including sample mixing, SAXS measurement, continuous UV absorbance measurements, and cleaning of the channels and X-ray cell with buffer. The complete analysis...

  8. Results for the first quarter calendar year 2017 tank 50H salt solution sample

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, C. L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-04-12

    In this memorandum, the chemical and radionuclide contaminant results from the First Quarter Calendar Year 2017 (CY17) sample of Tank 50H salt solution are presented in tabulated form. The First Quarter CY17 Tank 50H samples [a 200 mL sample obtained 6” below the surface (HTF-50-17-7) and a 1 L sample obtained 66” from the tank bottom (HTF-50-17-8)] were obtained on January 15, 2017 and received at Savannah River National Laboratory (SRNL) on January 16, 2017. Prior to obtaining the samples from Tank 50H, a single pump was run at least 4.4 hours and the samples were pulled immediately after pump shut down. All volatile organic analysis (VOA) and semi-volatile organic analysis (SVOA) were performed on the surface sample and all other analyses were performed on the variable depth sample. The information from this characterization will be used by Savannah River Remediation (SRR) for the transfer of aqueous waste from Tank 50H to the Saltstone Production Facility, where the waste will be treated and disposed of in the Saltstone Disposal Facility. This memorandum compares results, where applicable, to Saltstone Waste Acceptance Criteria (WAC) limits and targets. The chemical and radionuclide contaminant results from the characterization of the First Quarter CY17 sampling of Tank 50H were requested by SRR personnel and details of the testing are presented in the SRNL Task Technical and Quality Assurance Plan (TTQAP). This memorandum is part of Deliverable 2 from SRR request. Data pertaining to the regulatory limits for Resource Conservation and Recovery Act (RCRA) metals will be documented at a later time per the TTQAP for the Tank 50H saltstone task.

  9. Radiochromic liquid solution

    International Nuclear Information System (INIS)

    Noakes, J.E.; Culp, R.A.

    1983-01-01

    A radiochromic solution which is sensitive to small dosages of ionizing and ultraviolet radiation is described. It consists of a solution of a leucocyanide dye in a clear polar solvent with enough organic acid added to make the solution at least slightly acidic and responds to radiation by permanently changing color. Up to one half of the solution by weight can be replaced by a second solution of an aromatic solvent and an organic fluor. Another modification of the invention is a solution of a leucocyanide dye in a clear polar solvent having an aromatic group, an organic fluor, and enough organic acid to make the solution at least slightly acidic. (author)

  10. On rotational solutions for elliptically excited pendulum

    International Nuclear Information System (INIS)

    Belyakov, Anton O.

    2011-01-01

    The author considers the planar rotational motion of the mathematical pendulum with its pivot oscillating both vertically and horizontally, so the trajectory of the pivot is an ellipse close to a circle. The analysis is based on the exact rotational solutions in the case of circular pivot trajectory and zero gravity. The conditions for existence and stability of such solutions are derived. Assuming that the amplitudes of excitations are not small while the pivot trajectory has small ellipticity the approximate solutions are found both for high and small linear dampings. Comparison between approximate and numerical solutions is made for different values of the damping parameter. -- Highlights: → We study rotations of the mathematical pendulum when its pivot moves along an ellipse. → There are stable exact solutions for a circular pivot trajectory and zero gravity. → Asymptotic solutions are found for an elliptical pivot trajectory

  11. A simple technique for measuring the superconducting critical temperature of small (>= 10 μg) samples

    International Nuclear Information System (INIS)

    Pereira, R.F.R.; Meyer, E.; Silveira, M.F. da.

    1983-01-01

    A simple technique for measuring the superconducting critical temperature of small (>=10μg) samples is described. The apparatus is built in the form of a probe, which can be introduced directly into a liquid He storage dewar and permits the determination of the critical temperature, with an imprecision of +- 0.05 K above 4.2 K, in about 10 minutes. (Author) [pt

  12. An Inset CT Specimen for Evaluating Fracture in Small Samples of Material

    Science.gov (United States)

    Yahyazadehfar, M.; Nazari, A.; Kruzic, J.J.; Quinn, G.D.; Arola, D.

    2013-01-01

    In evaluations on the fracture behavior of hard tissues and many biomaterials, the volume of material available to study is not always sufficient to apply a standard method of practice. In the present study an inset Compact Tension (inset CT) specimen is described, which uses a small cube of material (approximately 2×2×2 mm3) that is molded within a secondary material to form the compact tension geometry. A generalized equation describing the Mode I stress intensity was developed for the specimen using the solutions from a finite element model that was defined over permissible crack lengths, variations in specimen geometry, and a range in elastic properties of the inset and mold materials. A validation of the generalized equation was performed using estimates for the fracture toughness of a commercial dental composite via the “inset CT” specimen and the standard geometry defined by ASTM E399. Results showed that the average fracture toughness obtained from the new specimen (1.23 ± 0.02 MPa•m0.5) was within 2% of that from the standard. Applications of the inset CT specimen are presented for experimental evaluations on the crack growth resistance of dental enamel and root dentin, including their fracture resistance curves. Potential errors in adopting this specimen are then discussed, including the effects of debonding between the inset and molding material on the estimated stress intensity distribution. Results of the investigation show that the inset CT specimen offers a viable approach for studying the fracture behavior of small volumes of structural materials. PMID:24268892

  13. Autoclave corrosion of zircaloy-4 cladding samples in LiOH solutions

    International Nuclear Information System (INIS)

    Hermann, A.

    2010-03-01

    In reactor operation, pH of the cooling water is adjusted by addition of alkaline hydroxides, and LiOH has been found to be the most suitable one. The addition of LiOH above a certain concentration level (depending on temperature) increases the corrosion rate of zirconium and its alloys. Hydrogen pick-up by the metal is also increased, and this effect is used to produce hydrided specimens for different investigations using the corrosion reaction. At the Paul Scherrer Institute several projects were accomplished to investigate the influence of hydrogen in Zircaloy cladding on its mechanical properties. In order to produce hydrided specimens for comparison and for adjusting new equipment, Zircaloy tubing samples were hydrogen charged by autoclave corrosion in lithiated water. Results of the corrosion experiments are outlined in this publication. Because of the great variety of possible experimental parameters these results are still of interest for the scientific community. Autoclave corrosion was accomplished in 0.2 M or 0.5 M LiOH solution at a constant temperature of 340 o C and a pressure of 160 bar. The corrosion rate increases from 84 mg/(dm 2 d) in 0.2 M LiOH to 153 mg/(dm 2 d) in 0.5 M LiOH. The hydrogen pick-up fraction in 0.5 M LiOH amounts to 80%. In 0.5 M LiOH, Zircaloy tubing samples can be charged with ∼ 500 ppm hydrogen in about 40 hours. In the corrosion experiments described in this report a homogeneous distribution of hydrides should be expected (except very high hydride concentrations) because no temperature gradient exists through the tubing wall. Hydrogen stringers are homogeneously distributed with circumferential orientation (stress-relieved tubing samples). (author)

  14. Forward flux sampling calculation of homogeneous nucleation rates from aqueous NaCl solutions.

    Science.gov (United States)

    Jiang, Hao; Haji-Akbari, Amir; Debenedetti, Pablo G; Panagiotopoulos, Athanassios Z

    2018-01-28

    We used molecular dynamics simulations and the path sampling technique known as forward flux sampling to study homogeneous nucleation of NaCl crystals from supersaturated aqueous solutions at 298 K and 1 bar. Nucleation rates were obtained for a range of salt concentrations for the Joung-Cheatham NaCl force field combined with the Extended Simple Point Charge (SPC/E) water model. The calculated nucleation rates are significantly lower than the available experimental measurements. The estimates for the nucleation rates in this work do not rely on classical nucleation theory, but the pathways observed in the simulations suggest that the nucleation process is better described by classical nucleation theory than an alternative interpretation based on Ostwald's step rule, in contrast to some prior simulations of related models. In addition to the size of NaCl nucleus, we find that the crystallinity of a nascent cluster plays an important role in the nucleation process. Nuclei with high crystallinity were found to have higher growth probability and longer lifetimes, possibly because they are less exposed to hydration water.

  15. Sophistication of 14C measurement at JAEA-AMS-MUTSU. Attempt on a small quantity of sample

    International Nuclear Information System (INIS)

    Tanaka, Takayuki; Kabuto, Shoji; Kinoshita, Naoki; Yamamoto, Nobuo

    2010-01-01

    In the investigations on substance dynamics using the molecular weight and chemical fractionation, the utilization of 14 C measurement by an accelerator mass spectrometry (AMS) have started. As a result of the fractionation, sample contents required for AMS measurement have been downsized. We expect that this trend toward a small quantity of sample will be steadily accelerated in the future. As 14 C measurement by AMS established at Mutsu office require about 2 mg of sample content at present, our AMS lags behind the others in the trend. We try to downsize the needed sample content for 14 C measurement by our AMS. In this study, we modified the shape of the target-piece in which the sample is packed and which is regularly needed to radiocarbon measurement by our AMS. Moreover, we improved on the apparatus needed to pack the sample. As a result of the improvement, we revealed that it is possible to measure the 14 C using our AMS even by the amount of the sample of about 0.5 mg. (author)

  16. Enrichment and determination of small amounts of 90Sr/90Y in water samples

    International Nuclear Information System (INIS)

    Mundschenk, H.

    1979-01-01

    Small amounts of 90 Sr/ 90 Y can be concentrated from large volumes of surface water (100 l) by precipitation of the phosphates, using bentonite as adsorber matrix. In the case of samples containing no or nearly no suspended matter (tap water, ground water, sea water), the daughter 90 Y can be extracted directly by using filter beds impregnated with HDEHP. The applicability of both techniques is demonstrated under realistic conditions. (orig.) 891 HP/orig. 892 MKO [de

  17. Basic distribution free identification tests for small size samples of environmental data

    Energy Technology Data Exchange (ETDEWEB)

    Federico, A.G.; Musmeci, F. [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Ambiente

    1998-01-01

    Testing two or more data sets for the hypothesis that they are sampled form the same population is often required in environmental data analysis. Typically the available samples have a small number of data and often then assumption of normal distributions is not realistic. On the other hand the diffusion of the days powerful Personal Computers opens new possible opportunities based on a massive use of the CPU resources. The paper reviews the problem introducing the feasibility of two non parametric approaches based on intrinsic equi probability properties of the data samples. The first one is based on a full re sampling while the second is based on a bootstrap approach. A easy to use program is presented. A case study is given based on the Chernobyl children contamination data. [Italiano] Nell`analisi di dati ambientali ricorre spesso il caso di dover sottoporre a test l`ipotesi di provenienza di due, o piu`, insiemi di dati dalla stessa popolazione. Tipicamente i dati disponibili sono pochi e spesso l`ipotesi di provenienza da distribuzioni normali non e` sostenibile. D`altra aprte la diffusione odierna di Personal Computer fornisce nuove possibili soluzioni basate sull`uso intensivo delle risorse della CPU. Il rapporto analizza il problema e presenta la possibilita` di utilizzo di due test non parametrici basati sulle proprieta` intrinseche di equiprobabilita` dei campioni. Il primo e` basato su una tecnica di ricampionamento esaustivo mentre il secondo su un approccio di tipo bootstrap. E` presentato un programma di semplice utilizzo e un caso di studio basato su dati di contaminazione di bambini a Chernobyl.

  18. Autoregressive Prediction with Rolling Mechanism for Time Series Forecasting with Small Sample Size

    Directory of Open Access Journals (Sweden)

    Zhihua Wang

    2014-01-01

    Full Text Available Reasonable prediction makes significant practical sense to stochastic and unstable time series analysis with small or limited sample size. Motivated by the rolling idea in grey theory and the practical relevance of very short-term forecasting or 1-step-ahead prediction, a novel autoregressive (AR prediction approach with rolling mechanism is proposed. In the modeling procedure, a new developed AR equation, which can be used to model nonstationary time series, is constructed in each prediction step. Meanwhile, the data window, for the next step ahead forecasting, rolls on by adding the most recent derived prediction result while deleting the first value of the former used sample data set. This rolling mechanism is an efficient technique for its advantages of improved forecasting accuracy, applicability in the case of limited and unstable data situations, and requirement of little computational effort. The general performance, influence of sample size, nonlinearity dynamic mechanism, and significance of the observed trends, as well as innovation variance, are illustrated and verified with Monte Carlo simulations. The proposed methodology is then applied to several practical data sets, including multiple building settlement sequences and two economic series.

  19. A Complete First-Order Analytical Solution for Optimal Low-Thrust Limited-Power Transfers Between Coplanar Orbits with Small Eccentricities

    Science.gov (United States)

    Da Silva Fernandes, Sandro; Das Chagas Carvalho, Francisco; Vilhena de Moraes, Rodolpho

    The purpose of this work is to present a complete first order analytical solution, which includes short periodic terms, for the problem of optimal low-thrust limited power trajectories with large amplitude transfers (no rendezvous) between coplanar orbits with small eccentricities in Newtonian central gravity field. The study of these transfers is particularly interesting because the orbits found in practice often have a small eccentricity and the problem of transferring a vehicle from a low earth orbit to a high earth orbit is frequently found. Besides, the analysis has been motivated by the renewed interest in the use of low-thrust propulsion systems in space missions verified in the last two decades. Several researchers have obtained numerical and sometimes analytical solutions for a number of specific initial orbits and specific thrust profiles. Averaging methods are also used in such researches. Firstly, the optimization problem associated to the space transfer problem is formulated as a Mayer problem of optimal control with Cartesian elements - position and velocity vectors - as state variables. After applying the Pontryagin Maximum Principle, successive Mathieu transformations are performed and suitable sets of orbital elements are introduced. The short periodic terms are eliminated from the maximum Hamiltonian function through an infinitesimal canonical transformation built through Hori method - a perturbation canonical method based on Lie series. The new Hamiltonian function, which results from the infinitesimal canonical transformation, describes the extremal trajectories for long duration maneuvers. Closed-form analytical solutions are obtained for the new canonical system by solving the Hamilton-Jacobi equation through the separation of variables technique. By applying the transformation equations of the algorithm of Hori method, a first order analytical solution for the problem is obtained in non-singular orbital elements. For long duration maneuvers

  20. Measuring Blood Glucose Concentrations in Photometric Glucometers Requiring Very Small Sample Volumes.

    Science.gov (United States)

    Demitri, Nevine; Zoubir, Abdelhak M

    2017-01-01

    Glucometers present an important self-monitoring tool for diabetes patients and, therefore, must exhibit high accuracy as well as good usability features. Based on an invasive photometric measurement principle that drastically reduces the volume of the blood sample needed from the patient, we present a framework that is capable of dealing with small blood samples, while maintaining the required accuracy. The framework consists of two major parts: 1) image segmentation; and 2) convergence detection. Step 1 is based on iterative mode-seeking methods to estimate the intensity value of the region of interest. We present several variations of these methods and give theoretical proofs of their convergence. Our approach is able to deal with changes in the number and position of clusters without any prior knowledge. Furthermore, we propose a method based on sparse approximation to decrease the computational load, while maintaining accuracy. Step 2 is achieved by employing temporal tracking and prediction, herewith decreasing the measurement time, and, thus, improving usability. Our framework is tested on several real datasets with different characteristics. We show that we are able to estimate the underlying glucose concentration from much smaller blood samples than is currently state of the art with sufficient accuracy according to the most recent ISO standards and reduce measurement time significantly compared to state-of-the-art methods.

  1. Strategies for Small Volume Resuscitation: Hyperosmotic-Hyperoncotic Solutions, Hemoglobin Based Oxygen Carriers and Closed-Loop Resuscitation

    Science.gov (United States)

    Kramer, George C.; Wade, Charles E.; Dubick, Michael A.; Atkins, James L.

    2004-01-01

    Introduction: Logistic constraints on combat casualty care preclude traditional resuscitation strategies which can require volumes and weights 3 fold or greater than hemorrhaged volume. We present a review of quantitative analyses of clinical and animal data on small volume strategies using 1) hypertonic-hyperosmotic solutions (HHS); 2) hemoglobin based oxygen carriers (HBOCs) and 3) closed-loop infusion regimens.Methods and Results: Literature searches and recent queries to industry and academic researchers have allowed us to evaluate the record of 81 human HHS studies (12 trauma trials), 19 human HBOCs studies (3trauma trials) and two clinical studies of closed-loop resuscitation.There are several hundreds animal studies and at least 82 clinical trials and reports evaluating small volume7.2%-7.5% hypertonic saline (HS) most often combined with colloids, e.g., dextran (HSD) or hetastarch(HSS). HSD and HSS data has been published for 1,108 and 392 patients, respectively. Human studies have documented volume sparing and hemodynamic improvements. Meta-analyses suggest improved survival for hypotensive trauma patients treated with HSD with significant reductions in mortality found for patients with blood pressure surgery. HSD and HSS have received regulatory approval in 14 and 3 countries, respectively, with 81,000+ units sold. The primary reported use was head injury and trauma resuscitation. Complications and reported adverse events are surprisingly rare and not significantly different from other solutions.HBOCs are potent volume expanders in addition to oxygen carriers with volume expansion greater than standard colloids. Several investigators have evaluated small volume hyperoncotic HBOCs or HS-HBOC formulations for hypotensive and normotensive resuscitation in animals. A consistent finding in resuscitation with HBOCs is depressed cardiac output. There is some evidence that HBOCs more efficiently unload oxygen from plasma hemoglobin as well as facilitate RBC

  2. Characteristic Performance Evaluation of a new SAGe Well Detector for Small and Large Sample Geometries

    International Nuclear Information System (INIS)

    Adekola, A.S.; Colaresi, J.; Douwen, J.; Jaederstroem, H.; Mueller, W.F.; Yocum, K.M.; Carmichael, K.

    2015-01-01

    Environmental scientific research requires a detector that has sensitivity low enough to reveal the presence of any contaminant in the sample at a reasonable counting time. Canberra developed the germanium detector geometry called Small Anode Germanium (SAGe) Well detector, which is now available commercially. The SAGe Well detector is a new type of low capacitance germanium well detector manufactured using small anode technology capable of advancing many environmental scientific research applications. The performance of this detector has been evaluated for a range of sample sizes and geometries counted inside the well, and on the end cap of the detector. The detector has energy resolution performance similar to semi-planar detectors, and offers significant improvement over the existing coaxial and Well detectors. Energy resolution performance of 750 eV Full Width at Half Maximum (FWHM) at 122 keV γ-ray energy and resolution of 2.0 - 2.3 keV FWHM at 1332 keV γ-ray energy are guaranteed for detector volumes up to 425 cm 3 . The SAGe Well detector offers an optional 28 mm well diameter with the same energy resolution as the standard 16 mm well. Such outstanding resolution performance will benefit environmental applications in revealing the detailed radionuclide content of samples, particularly at low energy, and will enhance the detection sensitivity resulting in reduced counting time. The detector is compatible with electric coolers without any sacrifice in performance and supports the Canberra Mathematical efficiency calibration method (In situ Object Calibration Software or ISOCS, and Laboratory Source-less Calibration Software or LABSOCS). In addition, the SAGe Well detector supports true coincidence summing available in the ISOCS/LABSOCS framework. The improved resolution performance greatly enhances detection sensitivity of this new detector for a range of sample sizes and geometries counted inside the well. This results in lower minimum detectable

  3. Characteristic Performance Evaluation of a new SAGe Well Detector for Small and Large Sample Geometries

    Energy Technology Data Exchange (ETDEWEB)

    Adekola, A.S.; Colaresi, J.; Douwen, J.; Jaederstroem, H.; Mueller, W.F.; Yocum, K.M.; Carmichael, K. [Canberra Industries Inc., 800 Research Parkway, Meriden, CT 06450 (United States)

    2015-07-01

    Environmental scientific research requires a detector that has sensitivity low enough to reveal the presence of any contaminant in the sample at a reasonable counting time. Canberra developed the germanium detector geometry called Small Anode Germanium (SAGe) Well detector, which is now available commercially. The SAGe Well detector is a new type of low capacitance germanium well detector manufactured using small anode technology capable of advancing many environmental scientific research applications. The performance of this detector has been evaluated for a range of sample sizes and geometries counted inside the well, and on the end cap of the detector. The detector has energy resolution performance similar to semi-planar detectors, and offers significant improvement over the existing coaxial and Well detectors. Energy resolution performance of 750 eV Full Width at Half Maximum (FWHM) at 122 keV γ-ray energy and resolution of 2.0 - 2.3 keV FWHM at 1332 keV γ-ray energy are guaranteed for detector volumes up to 425 cm{sup 3}. The SAGe Well detector offers an optional 28 mm well diameter with the same energy resolution as the standard 16 mm well. Such outstanding resolution performance will benefit environmental applications in revealing the detailed radionuclide content of samples, particularly at low energy, and will enhance the detection sensitivity resulting in reduced counting time. The detector is compatible with electric coolers without any sacrifice in performance and supports the Canberra Mathematical efficiency calibration method (In situ Object Calibration Software or ISOCS, and Laboratory Source-less Calibration Software or LABSOCS). In addition, the SAGe Well detector supports true coincidence summing available in the ISOCS/LABSOCS framework. The improved resolution performance greatly enhances detection sensitivity of this new detector for a range of sample sizes and geometries counted inside the well. This results in lower minimum detectable

  4. Quantitative Characterization of Configurational Space Sampled by HIV-1 Nucleocapsid Using Solution NMR, X-ray Scattering and Protein Engineering.

    Science.gov (United States)

    Deshmukh, Lalit; Schwieters, Charles D; Grishaev, Alexander; Clore, G Marius

    2016-06-03

    Nucleic-acid-related events in the HIV-1 replication cycle are mediated by nucleocapsid, a small protein comprising two zinc knuckles connected by a short flexible linker and flanked by disordered termini. Combining experimental NMR residual dipolar couplings, solution X-ray scattering and protein engineering with ensemble simulated annealing, we obtain a quantitative description of the configurational space sampled by the two zinc knuckles, the linker and disordered termini in the absence of nucleic acids. We first compute the conformational ensemble (with an optimal size of three members) of an engineered nucleocapsid construct lacking the N- and C-termini that satisfies the experimental restraints, and then validate this ensemble, as well as characterize the disordered termini, using the experimental data from the full-length nucleocapsid construct. The experimental and computational strategy is generally applicable to multidomain proteins. Differential flexibility within the linker results in asymmetric motion of the zinc knuckles which may explain their functionally distinct roles despite high sequence identity. One of the configurations (populated at a level of ≈40 %) closely resembles that observed in various ligand-bound forms, providing evidence for conformational selection and a mechanistic link between protein dynamics and function. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Structure and dynamics of nonaqueous electrolyte solutions by small angle neutron scattering, brownian dynamics and primitive model theories

    International Nuclear Information System (INIS)

    Kunz, W.; Turq, P.

    1990-01-01

    The study of electrolyte solutions by small angle neutron scattering (static) of quasi-elastic neutron scattering (dynamics) gives new perspectives to the primitive model of electrolytes, for both static and dynamic properties of those systems. Whereas all properties can be interpreted by brownian dynamics, integral equations cannot be used at the present time to get transport coefficients in all cases. As regards the choice of the potentials at the McMillan Mayer level, specific Gurney terms for solvation are not needed for tetraalkylammonium salts. (orig.)

  6. Sample Preparation and Extraction in Small Sample Volumes Suitable for Pediatric Clinical Studies: Challenges, Advances, and Experiences of a Bioanalytical HPLC-MS/MS Method Validation Using Enalapril and Enalaprilat

    Science.gov (United States)

    Burckhardt, Bjoern B.; Laeer, Stephanie

    2015-01-01

    In USA and Europe, medicines agencies force the development of child-appropriate medications and intend to increase the availability of information on the pediatric use. This asks for bioanalytical methods which are able to deal with small sample volumes as the trial-related blood lost is very restricted in children. Broadly used HPLC-MS/MS, being able to cope with small volumes, is susceptible to matrix effects. The latter restrains the precise drug quantification through, for example, causing signal suppression. Sophisticated sample preparation and purification utilizing solid-phase extraction was applied to reduce and control matrix effects. A scale-up from vacuum manifold to positive pressure manifold was conducted to meet the demands of high-throughput within a clinical setting. Faced challenges, advances, and experiences in solid-phase extraction are exemplarily presented on the basis of the bioanalytical method development and validation of low-volume samples (50 μL serum). Enalapril, enalaprilat, and benazepril served as sample drugs. The applied sample preparation and extraction successfully reduced the absolute and relative matrix effect to comply with international guidelines. Recoveries ranged from 77 to 104% for enalapril and from 93 to 118% for enalaprilat. The bioanalytical method comprising sample extraction by solid-phase extraction was fully validated according to FDA and EMA bioanalytical guidelines and was used in a Phase I study in 24 volunteers. PMID:25873972

  7. Sample Preparation and Extraction in Small Sample Volumes Suitable for Pediatric Clinical Studies: Challenges, Advances, and Experiences of a Bioanalytical HPLC-MS/MS Method Validation Using Enalapril and Enalaprilat

    Directory of Open Access Journals (Sweden)

    Bjoern B. Burckhardt

    2015-01-01

    Full Text Available In USA and Europe, medicines agencies force the development of child-appropriate medications and intend to increase the availability of information on the pediatric use. This asks for bioanalytical methods which are able to deal with small sample volumes as the trial-related blood lost is very restricted in children. Broadly used HPLC-MS/MS, being able to cope with small volumes, is susceptible to matrix effects. The latter restrains the precise drug quantification through, for example, causing signal suppression. Sophisticated sample preparation and purification utilizing solid-phase extraction was applied to reduce and control matrix effects. A scale-up from vacuum manifold to positive pressure manifold was conducted to meet the demands of high-throughput within a clinical setting. Faced challenges, advances, and experiences in solid-phase extraction are exemplarily presented on the basis of the bioanalytical method development and validation of low-volume samples (50 μL serum. Enalapril, enalaprilat, and benazepril served as sample drugs. The applied sample preparation and extraction successfully reduced the absolute and relative matrix effect to comply with international guidelines. Recoveries ranged from 77 to 104% for enalapril and from 93 to 118% for enalaprilat. The bioanalytical method comprising sample extraction by solid-phase extraction was fully validated according to FDA and EMA bioanalytical guidelines and was used in a Phase I study in 24 volunteers.

  8. Characterization of Nanoparticles and Colloids in Aquatic Systems 1. Small Angle Neutron Scattering Investigations of Suwannee River Fulvic Acid Aggregates in Aqueous Solutions

    International Nuclear Information System (INIS)

    Diallo, Mamadou S.; Glinka, Charles J.; Goddard, William A.; Johnson, James H.

    2005-01-01

    Fulvic acids (FA) and humic acids (HA) constitute 30-50% of dissolved organic matter in natural aquatic systems. In aqueous solutions, a commonly accepted view is that FA and HA exist as soluble macroligands at low concentration and as supramolecular aggregates at higher concentration. The size, shape and structure of these aggregates are still the subject of ongoing debate in the environmental chemistry literature. In this article, we use small angle neutron scattering (SANS) to assess the effects of solute concentration, solution pH and background electrolyte (NaCl) concentration on the structures of Suwannee River FA (SRFA) aggregates in D 2 O. The qualitative features of the SANS curves and data analysis are not consistent with the view point that SRFA forms micelle-like aggregates as its concentration in aqueous solution increases. We find that SRFA forms fractal aggregates in D 2 0 with size greater than 242 nm. The SRFA aggregates undergo a significant degree of restructuring in compactness as solution pH, solute concentration and NaCl concentration increase

  9. Assay of fissionable isotopes in aqueous solution by pulsed neutron interrogation

    International Nuclear Information System (INIS)

    Campbell, P.; Gardy, E.M.; Boase, D.G.

    1978-04-01

    Non-destructive assay of uranium-235 and thorium-232 in aqueous nitric acid solutions has been accomplished by irradiation with pulses of neutrons from a 14-MeV Cockcroft-Walton neutron generator, and counting of the delayed neutrons emitted from the fissions induced. Design of the delayed neutron detector assemblies is described, together with the neutron pulse timing and counting systems. The effects of irradiation time, counting time, neutron moderation, detector design and sample geometry on the delayed neutron response from uranium-235 and 238 and thorium-232 are discussed. By using polyethylene to moderate the interrogating neutrons, solutions can be analyzed for both uranium-235 and thorium. Comparative analyses with chemical and γ-spectrometric methods show good agreement. The neutron method is rapid and is shown to be unaffected by the presence in solution of impurities such as iron, nickel, chromium, and aluminum. With the experimental equipment described, detection limits of 0.6 mg of 235 U and 9 mg of 232 Th in a sample volume of 25 mL have been achieved. Analyses of highly radioactive samples may be done easily since the measurements are not affected by the presence of large amounts of βγ radiation. Samples can be enclosed in small lead-shielded flasks during analysis to protect the analyst. The potential of the technique to on-line analysis applications is explored briefly. (author)

  10. Structural and phase transition changes of sodium dodecyl sulfate micellar solution in alcohols probed by small-angle neutron scattering (SANS)

    Energy Technology Data Exchange (ETDEWEB)

    Putra, Edy Giri Rachman [Neutron Scattering Laboratory, National Nuclear Energy Agency of Indonesia (BATAN), Gedung 40 BATAN, Kawasan Puspiptek Serpong, Tangerang 15314 (Indonesia); Patriati, Arum [Neutron Scattering Laboratory, National Nuclear Energy Agency of Indonesia (BATAN), Gedung 40 BATAN, Kawasan Puspiptek Serpong, Tangerang 15314 (Indonesia); Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Gadjah Mada, Bulaksumur, Yogyakarta 55281, Indonesia giri@batan.go.id (Indonesia)

    2015-04-16

    Small-angle neutron scattering (SANS) measurements on 0.3M sodium dodecyl sulfate (SDS) micellar solutions have been performed in the presence of n-alcohols, from ethanol to decanol at different alcohol concentrations, 2–10 wt%. The ellipsoid micellar structure which occurred in the 0.3M SDS in aqueous solution with the size range of 30–50 Å has different behavior at various hydrocarbon chain length and concentration of alcohols. At low concentration and short chain-length of alcohols, such as ethanol, propanol, and butanol, the size of micelles reduced and had a spherical-like structure. The opposite effect occurred as medium to long chain alcohols, such as hexanol, octanol and decanol was added into the 0.3M SDS micellar solutions. The micelles structure changed to be more elongated in major axis and then crossed the critical phase transition from micellar solution into liquid crystal phase as lamellar structure emerged by further addition of alcohols. The inter-lamellar distances were also depending on the hydrocarbon chain length and concentration of alcohols. In the meantime, the persistent micellar structures occurred in addition of medium chain of n-alcohol, pentanol at all concentrations.

  11. Structural and phase transition changes of sodium dodecyl sulfate micellar solution in alcohols probed by small-angle neutron scattering (SANS)

    International Nuclear Information System (INIS)

    Putra, Edy Giri Rachman; Patriati, Arum

    2015-01-01

    Small-angle neutron scattering (SANS) measurements on 0.3M sodium dodecyl sulfate (SDS) micellar solutions have been performed in the presence of n-alcohols, from ethanol to decanol at different alcohol concentrations, 2–10 wt%. The ellipsoid micellar structure which occurred in the 0.3M SDS in aqueous solution with the size range of 30–50 Å has different behavior at various hydrocarbon chain length and concentration of alcohols. At low concentration and short chain-length of alcohols, such as ethanol, propanol, and butanol, the size of micelles reduced and had a spherical-like structure. The opposite effect occurred as medium to long chain alcohols, such as hexanol, octanol and decanol was added into the 0.3M SDS micellar solutions. The micelles structure changed to be more elongated in major axis and then crossed the critical phase transition from micellar solution into liquid crystal phase as lamellar structure emerged by further addition of alcohols. The inter-lamellar distances were also depending on the hydrocarbon chain length and concentration of alcohols. In the meantime, the persistent micellar structures occurred in addition of medium chain of n-alcohol, pentanol at all concentrations

  12. Studies in small angle scattering techniques

    International Nuclear Information System (INIS)

    Moellenbach, K.

    1980-03-01

    Small angle scattering of neutrons, X-rays and γ-rays are found among the spectroscopic methods developed in the recent years. Although these techniques differ from each other in many respects, e.g. radiation sources and technical equipment needed, their power to resolve physical phenomena and areas of application can be discussed in a general scheme. Selected examples are given illustrating the use of specific technical methods. Jahn-Teller driven structural phase transitions in Rare Earth zircons were studied with neutron scattering as well as small angle γ-ray diffraction. The study of neutron scattering from formations of magnetic domains in the Ising ferromagnet LiTbF 4 is a second example. Both these examples represent more than experimental test cases since the theoretical interpretations of the data obtained are discussed as well. As a last example the use of small angle scattering methods for the study of molecular biological samples is discussed. In particular the experimental procedures used in connection with scattering from aqueous solutions of proteins and protein complexes are given. (Auth.)

  13. Adiponectin levels measured in dried blood spot samples from neonates born small and appropriate for gestational age

    DEFF Research Database (Denmark)

    Klamer, A; Skogstrand, Kristin; Hougaard, D M

    2007-01-01

    Adiponectin levels measured in neonatal dried blood spot samples (DBSS) might be affected by both prematurity and being born small for gestational age (SGA). The aim of the study was to measure adiponectin levels in routinely collected neonatal DBSS taken on day 5 (range 3-12) postnatal from...

  14. The use of secondary ion mass spectrometry in forensic analyses of ultra-small samples

    Science.gov (United States)

    Cliff, John

    2010-05-01

    It is becoming increasingly important in forensic science to perform chemical and isotopic analyses on very small sample sizes. Moreover, in some instances the signature of interest may be incorporated in a vast background making analyses impossible by bulk methods. Recent advances in instrumentation make secondary ion mass spectrometry (SIMS) a powerful tool to apply to these problems. As an introduction, we present three types of forensic analyses in which SIMS may be useful. The causal organism of anthrax (Bacillus anthracis) chelates Ca and other metals during spore formation. Thus, the spores contain a trace element signature related to the growth medium that produced the organisms. Although other techniques have been shown to be useful in analyzing these signatures, the sample size requirements are generally relatively large. We have shown that time of flight SIMS (TOF-SIMS) combined with multivariate analysis, can clearly separate Bacillus sp. cultures prepared in different growth media using analytical spot sizes containing approximately one nanogram of spores. An important emerging field in forensic analysis is that of provenance of fecal pollution. The strategy of choice for these analyses-developing host-specific nucleic acid probes-has met with considerable difficulty due to lack of specificity of the probes. One potentially fruitful strategy is to combine in situ nucleic acid probing with high precision isotopic analyses. Bulk analyses of human and bovine fecal bacteria, for example, indicate a relative difference in d13C content of about 4 per mil. We have shown that sample sizes of several nanograms can be analyzed with the IMS 1280 with precisions capable of separating two per mil differences in d13C. The NanoSIMS 50 is capable of much better spatial resolution than the IMS 1280, albeit at a cost of analytical precision. Nevertheless we have documented precision capable of separating five per mil differences in d13C using analytical spots containing

  15. Sampling in Developmental Science: Situations, Shortcomings, Solutions, and Standards

    OpenAIRE

    Bornstein, Marc H.; Jager, Justin; Putnick, Diane L.

    2013-01-01

    Sampling is a key feature of every study in developmental science. Although sampling has far-reaching implications, too little attention is paid to sampling. Here, we describe, discuss, and evaluate four prominent sampling strategies in developmental science: population-based probability sampling, convenience sampling, quota sampling, and homogeneous sampling. We then judge these sampling strategies by five criteria: whether they yield representative and generalizable estimates of a study’s t...

  16. Results for the Fourth Quarter Calendar Year 2015 Tank 50H Salt Solution Sample

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-01-11

    In this memorandum, the chemical and radionuclide contaminant results from the Fourth Quarter Calendar Year 2015 (CY15) sample of Tank 50H salt solution are presented in tabulated form. The Fourth Quarter CY15 Tank 50H samples were obtained on October 29, 2015 and received at Savannah River National Laboratory (SRNL) on October 30, 2015. The information from this characterization will be used by Defense Waste Processing Facility (DWPF) & Saltstone Facility Engineering for the transfer of aqueous waste from Tank 50H to the Salt Feed Tank in the Saltstone Production Facility, where the waste will be treated and disposed of in the Saltstone Disposal Facility. This memorandum compares results, where applicable, to Saltstone Waste Acceptance Criteria (WAC) limits and targets. Data pertaining to the regulatory limits for Resource Conservation and Recovery Act (RCRA) metals will be documented at a later time per the Task Technical and Quality Assurance Plan (TTQAP) for the Tank 50H saltstone task. The chemical and radionuclide contaminant results from the characterization of the Fourth Quarter Calendar Year 2015 (CY15) sampling of Tank 50H were requested by SRR personnel and details of the testing are presented in the SRNL Task Technical and Quality Assurance Plan.

  17. Dynamic proton polarisation on polymers in solution: creating contrast in neutron scattering

    International Nuclear Information System (INIS)

    Grinten, M.G.D. van der

    1995-01-01

    Dynamic nuclear polarisation (DNP) as an alternative or additional method to create contrast in neutron small angle scattering has been investigated with emphasis on the study of polymers in solution. The need for high polarisations imposes specific requirements on the sample and its environment. Vitreous beads have been used as samples. Nuclear relaxation times show that they contain dissolved air. Parasitic scattering from the solvent is observed, probably arising from nanometer air bubbles. DNP is shown to be useful, in particular for samples that consist of mixtures of hydrogen-free and hydrogen-rich molecules, where the different molecules can be highlighted by changing the polarisation. ((orig.))

  18. Analysis of femtogram-sized plutonium samples by thermal ionization mass spectrometry

    International Nuclear Information System (INIS)

    Smith, D.H.; Duckworth, D.C.; Bostick, D.T.; Coleman, R.M.; McPherson, R.L.; McKown, H.S.

    1994-01-01

    The goal of this investigation was to extend the ability to perform isotopic analysis of plutonium to samples as small as possible. Plutonium ionizes thermally with quite good efficiency (first ionization potential 5.7 eV). Sub-nanogram sized samples can be analyzed on a near-routine basis given the necessary instrumentation. Efforts in this laboratory have been directed at rhenium-carbon systems; solutions of carbon in rhenium provide surfaces with work functions higher than pure rhenium (5.8 vs. ∼ 5.4 eV). Using a single resin bead as a sample loading medium both concentrates the sample nearly to a point and, due to its interaction with rhenium, produces the desired composite surface. Earlier work in this area showed that a layer of rhenium powder slurried in solution containing carbon substantially enhanced precision of isotopic measurements for uranium. Isotopic fractionation was virtually eliminated, and ionization efficiencies 2-5 times better than previously measured were attained for both Pu and U (1.7 and 0.5%, respectively). The other side of this coin should be the ability to analyze smaller samples, which is the subject of this report

  19. Oxygenation in carbonate microbialites and associated facies after the end-Permian mass extinction: Problems and potential solutions

    Directory of Open Access Journals (Sweden)

    Stephen Kershaw

    2018-01-01

    The oxygenation state of post-end-Permian extinction shallow marine facies continues to present a challenge of interpretation, and requires high-resolution sampling and careful attention to small-scale changes, as well as loss of rock through pressure solution, as the next step to resolve the issue.

  20. Sampling in Developmental Science: Situations, Shortcomings, Solutions, and Standards.

    Science.gov (United States)

    Bornstein, Marc H; Jager, Justin; Putnick, Diane L

    2013-12-01

    Sampling is a key feature of every study in developmental science. Although sampling has far-reaching implications, too little attention is paid to sampling. Here, we describe, discuss, and evaluate four prominent sampling strategies in developmental science: population-based probability sampling, convenience sampling, quota sampling, and homogeneous sampling. We then judge these sampling strategies by five criteria: whether they yield representative and generalizable estimates of a study's target population, whether they yield representative and generalizable estimates of subsamples within a study's target population, the recruitment efforts and costs they entail, whether they yield sufficient power to detect subsample differences, and whether they introduce "noise" related to variation in subsamples and whether that "noise" can be accounted for statistically. We use sample composition of gender, ethnicity, and socioeconomic status to illustrate and assess the four sampling strategies. Finally, we tally the use of the four sampling strategies in five prominent developmental science journals and make recommendations about best practices for sample selection and reporting.

  1. Exploring the structure of biological macromolecules in solution using Quokka, the small angle neutron scattering instrument, at ANSTO

    International Nuclear Information System (INIS)

    Wood, Kathleen; Jeffries, Cy M.; Knott, Robert B.; Sokolova, Anna; Jacques, David A.; Duff, Anthony P.

    2015-01-01

    Small angle neutron scattering (SANS) is widely used to extract structural parameters, shape and other types of information from a vast array of materials. The technique is applied to biological macromolecules and their complexes in solution to reveal information often not accessible by other techniques. SANS measurements on biomolecules present some particular challenges however, one of which is suitable instrumentation. This review details SANS experiments performed on two well-characterised globular proteins (lysozyme and glucose isomerase) using Quokka, the recently commissioned SANS instrument at the Australian Nuclear Science and Technology Organisation (ANSTO). The instrument configuration as well as data collection and reduction strategies for biological investigations are discussed and act as a general reference for structural biologists who use the instrument. Both model independent analysis of the two proteins and ab initio modelling illustrate that Quokka-SANS data can be used to successfully model the overall shapes of proteins in solution, providing a benchmark for users

  2. Tools for Inspecting and Sampling Waste in Underground Radioactive Storage Tanks with Small Access Riser Openings

    International Nuclear Information System (INIS)

    Nance, T.A.

    1998-01-01

    Underground storage tanks with 2 inches to 3 inches diameter access ports at the Department of Energy's Savannah River Site have been used to store radioactive solvents and sludge. In order to close these tanks, the contents of the tanks need to first be quantified in terms of volume and chemical and radioactive characteristics. To provide information on the volume of waste contained within the tanks, a small remote inspection system was needed. This inspection system was designed to provide lighting and provide pan and tilt capabilities in an inexpensive package with zoom abilities and color video. This system also needed to be utilized inside of a plastic tent built over the access port to contain any contamination exiting from the port. This system had to be build to travel into the small port opening, through the riser pipe, into the tank evacuated space, and out of the riser pipe and access port with no possibility of being caught and blocking the access riser. Long thin plates were found in many access riser pipes that blocked the inspection system from penetrating into the tank interiors. Retrieval tools to clear the plates from the tanks using developed sampling devices while providing safe containment for the samples. This paper will discuss the inspection systems, tools for clearing access pipes, and solvent sampling tools developed to evaluate the tank contents of the underground solvent storage tanks

  3. Sampling in Developmental Science: Situations, Shortcomings, Solutions, and Standards

    Science.gov (United States)

    Bornstein, Marc H.; Jager, Justin; Putnick, Diane L.

    2014-01-01

    Sampling is a key feature of every study in developmental science. Although sampling has far-reaching implications, too little attention is paid to sampling. Here, we describe, discuss, and evaluate four prominent sampling strategies in developmental science: population-based probability sampling, convenience sampling, quota sampling, and homogeneous sampling. We then judge these sampling strategies by five criteria: whether they yield representative and generalizable estimates of a study’s target population, whether they yield representative and generalizable estimates of subsamples within a study’s target population, the recruitment efforts and costs they entail, whether they yield sufficient power to detect subsample differences, and whether they introduce “noise” related to variation in subsamples and whether that “noise” can be accounted for statistically. We use sample composition of gender, ethnicity, and socioeconomic status to illustrate and assess the four sampling strategies. Finally, we tally the use of the four sampling strategies in five prominent developmental science journals and make recommendations about best practices for sample selection and reporting. PMID:25580049

  4. Asymptotic solution of the non-isothermal Cahn-Hilliard system

    International Nuclear Information System (INIS)

    Omel'yanov, G.A.

    1995-05-01

    The non-isothermal Cahn-Hillard questions with a small parameter in the n-dimensional case (n = 2.3) are considered. The small parameter is proportional both to the relaxation time and to the linear scale of transition zone, so the large time process is examined. The asymptotic solution describing the free interface dynamics is constructed. As the small parameter tends to zero, the limiting solution satisfies the modified Stefan problem with corrected Gibbs-Thomson law. The justification of the asymptotic solution is proved. (author). 26 refs

  5. Perspectives of an acoustic–electrostatic/electrodynamic hybrid levitator for small fluid and solid samples

    International Nuclear Information System (INIS)

    Lierke, E G; Holitzner, L

    2008-01-01

    The feasibility of an acoustic–electrostatic hybrid levitator for small fluid and solid samples is evaluated. A proposed design and its theoretical assessment are based on the optional implementation of simple hardware components (ring electrodes) and standard laboratory equipment into typical commercial ultrasonic standing wave levitators. These levitators allow precise electrical charging of drops during syringe- or ink-jet-type deployment. The homogeneous electric 'Millikan field' between the grounded ultrasonic transducer and the electrically charged reflector provide an axial compensation of the sample weight in an indifferent equilibrium, which can be balanced by using commercial optical position sensors in combination with standard electronic PID position control. Radial electrostatic repulsion forces between the charged sample and concentric ring electrodes of the same polarity provide stable positioning at the centre of the levitator. The levitator can be used in a pure acoustic or electrostatic mode or in a hybrid combination of both subsystems. Analytical evaluations of the radial–axial force profiles are verified with detailed numerical finite element calculations under consideration of alternative boundary conditions. The simple hardware modification with implemented double-ring electrodes in ac/dc operation is also feasible for an electrodynamic/acoustic hybrid levitator

  6. Strategies for Small Volume Resuscitation: Hyperosmotic-Hyperoncotic Solutions, Hemoglobin Based Oxygen Carriers and Closed-Loop Resuscitation

    Science.gov (United States)

    Kramer, George C.; Wade, Charles E.; Dubick, Michael A.; Atkins, James L.

    2004-01-01

    Introduction: Logistic constraints on combat casualty care preclude traditional resuscitation strategies which can require volumes and weights 3 fold or greater than hemorrhaged volume. We present a review of quantitative analyses of clinical and animal data on small volume strategies using 1) hypertonic-hyperosmotic solutions (HHS); 2) hemoglobin based oxygen carriers (HBOCs) and 3) closed-loop infusion regimens.Methods and Results: Literature searches and recent queries to industry and academic researchers have allowed us to evaluate the record of 81 human HHS studies (12 trauma trials), 19 human HBOCs studies (3trauma trials) and two clinical studies of closed-loop resuscitation.There are several hundreds animal studies and at least 82 clinical trials and reports evaluating small volume7.2%-7.5% hypertonic saline (HS) most often combined with colloids, e.g., dextran (HSD) or hetastarch(HSS). HSD and HSS data has been published for 1,108 and 392 patients, respectively. Human studies have documented volume sparing and hemodynamic improvements. Meta-analyses suggest improved survival for hypotensive trauma patients treated with HSD with significant reductions in mortality found for patients with blood pressure blood use and lower mortality compared to historic controls of patients refusing blood. Transfusion reductions with HBOC use have been modest. Two HBOCs (Hemopure and Polyheme) are now in new or planned large-scale multicenter prehospital trials of trauma treatment. A new implementation of small volume resuscitation is closed-loop resuscitation (CLR), which employs microprocessors to titrate just enough fluid to reach a physiologic target . Animal studies suggest less risk of rebleeding in uncontrolled hemorrhage and a reduction in fluid needs with CLR. The first clinical application of CLR was treatment of burn shock and the US Army. Conclusions: Independently sponsored civilian trauma trials and clinical evaluations in operational combat conditions of

  7. Solute-solvent cavity and bridge functions. I. Varying size of the solute

    International Nuclear Information System (INIS)

    Vyalov, I.; Chuev, G.; Georgi, N.

    2014-01-01

    In this work we present the results of the extensive molecular simulations of solute-solvent cavity and bridge functions. The mixtures of Lennard-Jones solvent with Lennard-Jones solute at infinite dilution are considered for different solute-solvent size ratios—up to 4:1. The Percus-Yevick and hypernetted chain closures deviate substantially from simulation results in the investigated temperature and density ranges. We also find that the behavior of the indirect and cavity correlation functions is non-monotonous within the hard-core region, but the latter can be successfully approximated by mean-field theory if the solute-solvent interaction energy is divided into repulsive and attractive contribution, according to Weeks-Chandler-Andersen theory. Furthermore, in spite of the non-monotonous behavior of logarithm of the cavity function and the indirect correlation function, their difference, i.e., the bridge function remains constant within the hard-core region. Such behavior of the bridge and indirect correlation functions at small distances and for small values of indirect correlation function is well known from the Duh-Haymet plots, where the non-unique relationship results in loops of the bridge function vs. indirect correlation function graphs. We show that the same pathological behavior appears also when distance is small and indirect correlation function is large. We further show that the unique functional behavior of the bridge function can be established when bridge is represented as a function of the renormalized, repulsive indirect correlation function

  8. Beyond simple small-angle X-ray scattering: developments in online complementary techniques and sample environments.

    Science.gov (United States)

    Bras, Wim; Koizumi, Satoshi; Terrill, Nicholas J

    2014-11-01

    Small- and wide-angle X-ray scattering (SAXS, WAXS) are standard tools in materials research. The simultaneous measurement of SAXS and WAXS data in time-resolved studies has gained popularity due to the complementary information obtained. Furthermore, the combination of these data with non X-ray based techniques, via either simultaneous or independent measurements, has advanced understanding of the driving forces that lead to the structures and morphologies of materials, which in turn give rise to their properties. The simultaneous measurement of different data regimes and types, using either X-rays or neutrons, and the desire to control parameters that initiate and control structural changes have led to greater demands on sample environments. Examples of developments in technique combinations and sample environment design are discussed, together with a brief speculation about promising future developments.

  9. Patient Safety Outcomes in Small Urban and Small Rural Hospitals

    Science.gov (United States)

    Vartak, Smruti; Ward, Marcia M.; Vaughn, Thomas E.

    2010-01-01

    Purpose: To assess patient safety outcomes in small urban and small rural hospitals and to examine the relationship of hospital and patient factors to patient safety outcomes. Methods: The Nationwide Inpatient Sample and American Hospital Association annual survey data were used for analyses. To increase comparability, the study sample was…

  10. Starfruit Leaves as Glucose Absorption Inhibitor in Mice’s Small Intestinal Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Rifqi Y Muhammad

    2016-12-01

    Full Text Available Background: Starfruit (Averrhoa carambola leaves contain flavone derivatives that exhibit anti-hyperglycemic effects. This study aims to determine the effect of starfruit leaves in reducing glucose absorption in intestinal epithelial cells of mice. Methods: This study was done by performing perfusion on the small intestines of mice. The mice that were used in this study were divided into four groups. The control group was given glucose solution without infused starfruit leaves whereas, the remaining 3 groups were given 3 mmol (540 mg/dL glucose solution with infused starfruit leaves of varying concentrations; 200, 400, and 600 mg/kg. Samples were collected at 0, 15th, 30th, 45th, and 60th minute. The sample was tested for glucose levels using spectrophotometry. Results: Test of significance showed a significant difference between the control group and the test group with p < 0.05. Conclusions: Starfruit leaves have a reduction effect towards glucose absorption in the small intestines in Wistar strains where the group using 600 mg/kg of infused starfruit leaves have the most significant effect as compared to other groups.

  11. Brighter for small power plants

    International Nuclear Information System (INIS)

    Haaland, Leif

    2003-01-01

    The article presents a small tunnel drilling machine aimed at using for the construction of small hydroelectric power plants and mentions briefly some advantages economically and environmentally of both the machine and the power production solution

  12. Small area estimation (SAE) model: Case study of poverty in West Java Province

    Science.gov (United States)

    Suhartini, Titin; Sadik, Kusman; Indahwati

    2016-02-01

    This paper showed the comparative of direct estimation and indirect/Small Area Estimation (SAE) model. Model selection included resolve multicollinearity problem in auxiliary variable, such as choosing only variable non-multicollinearity and implemented principal component (PC). Concern parameters in this paper were the proportion of agricultural venture poor households and agricultural poor households area level in West Java Province. The approach for estimating these parameters could be performed based on direct estimation and SAE. The problem of direct estimation, three area even zero and could not be conducted by directly estimation, because small sample size. The proportion of agricultural venture poor households showed 19.22% and agricultural poor households showed 46.79%. The best model from agricultural venture poor households by choosing only variable non-multicollinearity and the best model from agricultural poor households by implemented PC. The best estimator showed SAE better then direct estimation both of the proportion of agricultural venture poor households and agricultural poor households area level in West Java Province. The solution overcame small sample size and obtained estimation for small area was implemented small area estimation method for evidence higher accuracy and better precision improved direct estimator.

  13. Analytical solution of strongly nonlinear Duffing oscillators

    Directory of Open Access Journals (Sweden)

    A.M. El-Naggar

    2016-06-01

    Full Text Available In this paper, a new perturbation technique is employed to solve strongly nonlinear Duffing oscillators, in which a new parameter α=α(ε is defined such that the value of α is always small regardless of the magnitude of the original parameter ε. Therefore, the strongly nonlinear Duffing oscillators with large parameter ε are transformed into a small parameter system with respect to α. Approximate solution obtained by the present method is compared with the solution of energy balance method, homotopy perturbation method, global error minimization method and lastly numerical solution. We observe from the results that this method is very simple, easy to apply, and gives a very good accuracy not only for small parameter εbut also for large values of ε.

  14. Closed-form solution for the Wigner phase-space distribution function for diffuse reflection and small-angle scattering in a random medium.

    Science.gov (United States)

    Yura, H T; Thrane, L; Andersen, P E

    2000-12-01

    Within the paraxial approximation, a closed-form solution for the Wigner phase-space distribution function is derived for diffuse reflection and small-angle scattering in a random medium. This solution is based on the extended Huygens-Fresnel principle for the optical field, which is widely used in studies of wave propagation through random media. The results are general in that they apply to both an arbitrary small-angle volume scattering function, and arbitrary (real) ABCD optical systems. Furthermore, they are valid in both the single- and multiple-scattering regimes. Some general features of the Wigner phase-space distribution function are discussed, and analytic results are obtained for various types of scattering functions in the asymptotic limit s > 1, where s is the optical depth. In particular, explicit results are presented for optical coherence tomography (OCT) systems. On this basis, a novel way of creating OCT images based on measurements of the momentum width of the Wigner phase-space distribution is suggested, and the advantage over conventional OCT images is discussed. Because all previous published studies regarding the Wigner function are carried out in the transmission geometry, it is important to note that the extended Huygens-Fresnel principle and the ABCD matrix formalism may be used successfully to describe this geometry (within the paraxial approximation). Therefore for completeness we present in an appendix the general closed-form solution for the Wigner phase-space distribution function in ABCD paraxial optical systems for direct propagation through random media, and in a second appendix absorption effects are included.

  15. Ultra-trace plutonium determination in small volume seawater by sector field inductively coupled plasma mass spectrometry with application to Fukushima seawater samples.

    Science.gov (United States)

    Bu, Wenting; Zheng, Jian; Guo, Qiuju; Aono, Tatsuo; Tagami, Keiko; Uchida, Shigeo; Tazoe, Hirofumi; Yamada, Masatoshi

    2014-04-11

    Long-term monitoring of Pu isotopes in seawater is required for assessing Pu contamination in the marine environment from the Fukushima Dai-ichi Nuclear Power Plant accident. In this study, we established an accurate and precise analytical method based on anion-exchange chromatography and SF-ICP-MS. This method was able to determine Pu isotopes in seawater samples with small volumes (20-60L). The U decontamination factor was 3×10(7)-1×10(8), which provided sufficient removal of interfering U from the seawater samples. The estimated limits of detection for (239)Pu and (240)Pu were 0.11fgmL(-1) and 0.08fgmL(-1), respectively, which corresponded to 0.01mBqm(-3) for (239)Pu and 0.03mBqm(-3) for (240)Pu when a 20L volume of seawater was measured. We achieved good precision (2.9%) and accuracy (0.8%) for measurement of the (240)Pu/(239)Pu atom ratio in the standard Pu solution with a (239)Pu concentration of 11fgmL(-1) and (240)Pu concentration of 2.7fgmL(-1). Seawater reference materials were used for the method validation and both the (239+240)Pu activities and (240)Pu/(239)Pu atom ratios agreed well with the expected values. Surface and bottom seawater samples collected off Fukushima in the western North Pacific since March 2011 were analyzed. Our results suggested that there was no significant variation of the Pu distribution in seawater in the investigated areas compared to the distribution before the accident. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Computational model for simulation small testing launcher, technical solution

    Energy Technology Data Exchange (ETDEWEB)

    Chelaru, Teodor-Viorel, E-mail: teodor.chelaru@upb.ro [University POLITEHNICA of Bucharest - Research Center for Aeronautics and Space, Str. Ghe Polizu, nr. 1, Bucharest, Sector 1 (Romania); Cristian, Barbu, E-mail: barbucr@mta.ro [Military Technical Academy, Romania, B-dul. George Coşbuc, nr. 81-83, Bucharest, Sector 5 (Romania); Chelaru, Adrian, E-mail: achelaru@incas.ro [INCAS -National Institute for Aerospace Research Elie Carafoli, B-dul Iuliu Maniu 220, 061126, Bucharest, Sector 6 (Romania)

    2014-12-10

    The purpose of this paper is to present some aspects regarding the computational model and technical solutions for multistage suborbital launcher for testing (SLT) used to test spatial equipment and scientific measurements. The computational model consists in numerical simulation of SLT evolution for different start conditions. The launcher model presented will be with six degrees of freedom (6DOF) and variable mass. The results analysed will be the flight parameters and ballistic performances. The discussions area will focus around the technical possibility to realize a small multi-stage launcher, by recycling military rocket motors. From technical point of view, the paper is focused on national project 'Suborbital Launcher for Testing' (SLT), which is based on hybrid propulsion and control systems, obtained through an original design. Therefore, while classical suborbital sounding rockets are unguided and they use as propulsion solid fuel motor having an uncontrolled ballistic flight, SLT project is introducing a different approach, by proposing the creation of a guided suborbital launcher, which is basically a satellite launcher at a smaller scale, containing its main subsystems. This is why the project itself can be considered an intermediary step in the development of a wider range of launching systems based on hybrid propulsion technology, which may have a major impact in the future European launchers programs. SLT project, as it is shown in the title, has two major objectives: first, a short term objective, which consists in obtaining a suborbital launching system which will be able to go into service in a predictable period of time, and a long term objective that consists in the development and testing of some unconventional sub-systems which will be integrated later in the satellite launcher as a part of the European space program. This is why the technical content of the project must be carried out beyond the range of the existing suborbital

  17. Anomalous and resonance small-angle scattering

    International Nuclear Information System (INIS)

    Epperson, J.E.; Thiyagarajan, P.

    1988-01-01

    Significant changes in the small-angle scattered intensity can be induced by making measurements with radiation close to an absorption edge of an appropriate atomic species contained in the sample. These changes can be related quantitatively to the real and imaginary anomalous-dispersion terms for the scattering factor (X-rays) or scattering length (neutrons). The physics inherent in these anomalous-dispersion terms is first discussed before consideration of how they enter the relevant scattering theory. Two major areas of anomalous-scattering research have emerged; macromolecules in solution and unmixing of metallic alloys. Research in each area is reviewed, illustrating both the feasibility and potential of these techniques. All the experimental results reported to date have been obtained with X-rays. However, it is pointed out that the formalism is the same for the analog experiment with neutrons, and a number of suitable isotopes exist which exhibit resonance in an accessible range of energy. Potential applications of resonance small-angle neutron scattering are discussed. (orig.)

  18. Electrical Conductivity and Chemical Composition of Soil Solution: Comparison of Solution Samplers in Tropical Soils

    Directory of Open Access Journals (Sweden)

    Davi Lopes do Carmo

    2016-01-01

    Full Text Available ABSTRACT Soil solution samplers may have the same working principle, but they differ in relation to chemical and physical characteristics, cost and handling, and these aspects exert influence on the chemical composition of the soil solution obtained. This study was carried out to evaluate, over time, the chemical composition of solutions extracted by Suolo Acqua, with the hydrophilic membrane (HM as a standard, using soils with contrasting characteristics, and to determine the relationship between electrical conductivity (EC and concentration of ions and pH of soil solution samples. This study was carried out under laboratory conditions, using three soils samples with different clay and organic matter (OM contents. Soil solution contents of F−, Cl−, NO−3, Br−, SO42−, Na+, NH4+, K+, Mg2+, Ca2+, were analyzed, as well as inorganic, organic, and total C contents, pH, and EC, in four successive sampling times. Soil solution chemical composition extracted by the Suolo Acqua sampler is similar to that collected by the HM, but the Suolo Acqua extracted more Na+ and soluble organic C than the HM solution. Solution EC, cation and anion concentrations, and soluble C levels are higher in the soil with greater clay and OM contents (Latossolo and Cambissolo in this case. Soil solution composition varied over time, with considerable changes in pH, EC, and nutrient concentrations, especially associated with soil OM. Thus, single and isolated sampling of the soil solution must be avoided, otherwise composition of the soil solution may not be correctly evaluated. Soil solution EC was regulated by pH, as well as the sum of cation and anion concentrations, and the C contents determined in the soil liquid phase.

  19. Chartering Launchers for Small Satellites

    Science.gov (United States)

    Hernandez, Daniel

    The question of how to launch small satellites has been solved over the years by the larger launchers offering small satellites the possibility of piggy-backing. Specific fixtures have been developed and commercialized: Arianespace developed the ASAP interface, the USAF studied ESPA, NASA has promoted Shuttle launch possibilities, Russian authorities and companies have been able to find solutions with many different launchers... It is fair to say that most launcher suppliers have worked hard and finally often been able to find solutions to launch most small satellites into orbit. It is also true, however, that most of these small satellites were technology demonstration missions capable of accepting a wide range of orbit and launch characteristics: orbit altitude and inclination, launch date, etc. In some cases the small satellite missions required a well-defined type of orbit and have therefore been obliged to hire a small launcher on which they were the prime passenger. In our paper we would like to propose an additional solution to all these possibilities: launchers could plan well in advance (for example about 3 years), trips to precisely defined orbits to allow potential passengers to organize themselves and be ready on the D-Day. On the scheduled date the chartered launcher goes to the stated orbit while on another date, another chartered launcher goes to another orbit. The idea is to organize departures for space like trains or airplanes leaving on known schedules for known destinations.

  20. A TIMS-based method for the high precision measurements of the three-isotope potassium composition of small samples

    DEFF Research Database (Denmark)

    Wielandt, Daniel Kim Peel; Bizzarro, Martin

    2011-01-01

    A novel thermal ionization mass spectrometry (TIMS) method for the three-isotope analysis of K has been developed, and ion chromatographic methods for the separation of K have been adapted for the processing of small samples. The precise measurement of K-isotopes is challenged by the presence of ...

  1. An Integrated Solution-Based Rapid Sample Preparation Procedure for the Analysis of N-Glycans From Therapeutic Monoclonal Antibodies.

    Science.gov (United States)

    Aich, Udayanath; Liu, Aston; Lakbub, Jude; Mozdzanowski, Jacek; Byrne, Michael; Shah, Nilesh; Galosy, Sybille; Patel, Pramthesh; Bam, Narendra

    2016-03-01

    Consistent glycosylation in therapeutic monoclonal antibodies is a major concern in the biopharmaceutical industry as it impacts the drug's safety and efficacy and manufacturing processes. Large numbers of samples are created for the analysis of glycans during various stages of recombinant proteins drug development. Profiling and quantifying protein N-glycosylation is important but extremely challenging due to its microheterogeneity and more importantly the limitations of existing time-consuming sample preparation methods. Thus, a quantitative method with fast sample preparation is crucial for understanding, controlling, and modifying the glycoform variance in therapeutic monoclonal antibody development. Presented here is a rapid and highly quantitative method for the analysis of N-glycans from monoclonal antibodies. The method comprises a simple and fast solution-based sample preparation method that uses nontoxic reducing reagents for direct labeling of N-glycans. The complete work flow for the preparation of fluorescently labeled N-glycans takes a total of 3 h with less than 30 min needed for the release of N-glycans from monoclonal antibody samples. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  2. Equipment for collecting samples of radioactive solutions; Installation de prelevements d'echantillons de solutions radioactives

    Energy Technology Data Exchange (ETDEWEB)

    Raggenbass, A.; Fradin, J.; Joubert, G.

    1958-12-03

    The authors present an equipment aimed at collecting samples of fission products to perform radio-chemical analysis. As the sample must have a total activity between 1 and 50 micro-Curie, this installation comprises a sampling system and a dilution device which aims at bringing the sample to the suitable activity. Samples are collected by means of needles. The sample reproducibility is discussed. The dilution device is described.

  3. QNB: differential RNA methylation analysis for count-based small-sample sequencing data with a quad-negative binomial model.

    Science.gov (United States)

    Liu, Lian; Zhang, Shao-Wu; Huang, Yufei; Meng, Jia

    2017-08-31

    As a newly emerged research area, RNA epigenetics has drawn increasing attention recently for the participation of RNA methylation and other modifications in a number of crucial biological processes. Thanks to high throughput sequencing techniques, such as, MeRIP-Seq, transcriptome-wide RNA methylation profile is now available in the form of count-based data, with which it is often of interests to study the dynamics at epitranscriptomic layer. However, the sample size of RNA methylation experiment is usually very small due to its costs; and additionally, there usually exist a large number of genes whose methylation level cannot be accurately estimated due to their low expression level, making differential RNA methylation analysis a difficult task. We present QNB, a statistical approach for differential RNA methylation analysis with count-based small-sample sequencing data. Compared with previous approaches such as DRME model based on a statistical test covering the IP samples only with 2 negative binomial distributions, QNB is based on 4 independent negative binomial distributions with their variances and means linked by local regressions, and in the way, the input control samples are also properly taken care of. In addition, different from DRME approach, which relies only the input control sample only for estimating the background, QNB uses a more robust estimator for gene expression by combining information from both input and IP samples, which could largely improve the testing performance for very lowly expressed genes. QNB showed improved performance on both simulated and real MeRIP-Seq datasets when compared with competing algorithms. And the QNB model is also applicable to other datasets related RNA modifications, including but not limited to RNA bisulfite sequencing, m 1 A-Seq, Par-CLIP, RIP-Seq, etc.

  4. A compact time-of-flight SANS instrument optimised for measurements of small sample volumes at the European Spallation Source

    Energy Technology Data Exchange (ETDEWEB)

    Kynde, Søren, E-mail: kynde@nbi.ku.dk [Niels Bohr Institute, University of Copenhagen (Denmark); Hewitt Klenø, Kaspar [Niels Bohr Institute, University of Copenhagen (Denmark); Nagy, Gergely [SINQ, Paul Scherrer Institute (Switzerland); Mortensen, Kell; Lefmann, Kim [Niels Bohr Institute, University of Copenhagen (Denmark); Kohlbrecher, Joachim, E-mail: Joachim.kohlbrecher@psi.ch [SINQ, Paul Scherrer Institute (Switzerland); Arleth, Lise, E-mail: arleth@nbi.ku.dk [Niels Bohr Institute, University of Copenhagen (Denmark)

    2014-11-11

    The high flux at European Spallation Source (ESS) will allow for performing experiments with relatively small beam-sizes while maintaining a high intensity of the incoming beam. The pulsed nature of the source makes the facility optimal for time-of-flight small-angle neutron scattering (ToF-SANS). We find that a relatively compact SANS instrument becomes the optimal choice in order to obtain the widest possible q-range in a single setting and the best possible exploitation of the neutrons in each pulse and hence obtaining the highest possible flux at the sample position. The instrument proposed in the present article is optimised for performing fast measurements of small scattering volumes, typically down to 2×2×2 mm{sup 3}, while covering a broad q-range from about 0.005 1/Å to 0.5 1/Å in a single instrument setting. This q-range corresponds to that available at a typical good BioSAXS instrument and is relevant for a wide set of biomacromolecular samples. A central advantage of covering the whole q-range in a single setting is that each sample has to be loaded only once. This makes it convenient to use the fully automated high-throughput flow-through sample changers commonly applied at modern synchrotron BioSAXS-facilities. The central drawback of choosing a very compact instrument is that the resolution in terms of δλ/λ obtained with the short wavelength neutrons becomes worse than what is usually the standard at state-of-the-art SANS instruments. Our McStas based simulations of the instrument performance for a set of characteristic biomacromolecular samples show that the resulting smearing effects still have relatively minor effects on the obtained data and can be compensated for in the data analysis. However, in cases where a better resolution is required in combination with the large simultaneous q-range characteristic of the instrument, we show that this can be obtained by inserting a set of choppers.

  5. A Wavefront Division Polarimeter for the Measurements of Solute Concentrations in Solutions

    Directory of Open Access Journals (Sweden)

    Sergio Calixto

    2017-12-01

    Full Text Available Polarimeters are useful instruments that measure concentrations of optically active substances in a given solution. The conventional polarimetric principle consists of measuring the rotation angle of linearly polarized light. Here, we present a novel polarimeter based on the study of interference patterns. A Mach–Zehnder interferometer with linearly polarized light at the input is used. One beam passes through the liquid sample and the other is a reference beam. As the linearly polarized sample beam propagates through the optically active solution the vibration plane of the electric field will rotate. As a result, the visibility of the interference pattern at the interferometer output will decrease. Fringe contrast will be maximum when both beams present a polarization perpendicular to the plane of incidence. However, minimum visibility is obtained when, after propagation through the sample the polarization of the sample beam is oriented parallel to the plane of incidence. By using different solute concentrations, a calibration plot is obtained showing the behavior of visibility.

  6. Analytical solutions for the surface response to small amplitude perturbations in boundary data in the shallow-ice-stream approximation

    Directory of Open Access Journals (Sweden)

    G. H. Gudmundsson

    2008-07-01

    Full Text Available New analytical solutions describing the effects of small-amplitude perturbations in boundary data on flow in the shallow-ice-stream approximation are presented. These solutions are valid for a non-linear Weertman-type sliding law and for Newtonian ice rheology. Comparison is made with corresponding solutions of the shallow-ice-sheet approximation, and with solutions of the full Stokes equations. The shallow-ice-stream approximation is commonly used to describe large-scale ice stream flow over a weak bed, while the shallow-ice-sheet approximation forms the basis of most current large-scale ice sheet models. It is found that the shallow-ice-stream approximation overestimates the effects of bed topography perturbations on surface profile for wavelengths less than about 5 to 10 ice thicknesses, the exact number depending on values of surface slope and slip ratio. For high slip ratios, the shallow-ice-stream approximation gives a very simple description of the relationship between bed and surface topography, with the corresponding transfer amplitudes being close to unity for any given wavelength. The shallow-ice-stream estimates for the timescales that govern the transient response of ice streams to external perturbations are considerably more accurate than those based on the shallow-ice-sheet approximation. In particular, in contrast to the shallow-ice-sheet approximation, the shallow-ice-stream approximation correctly reproduces the short-wavelength limit of the kinematic phase speed given by solving a linearised version of the full Stokes system. In accordance with the full Stokes solutions, the shallow-ice-sheet approximation predicts surface fields to react weakly to spatial variations in basal slipperiness with wavelengths less than about 10 to 20 ice thicknesses.

  7. Solution-processed small molecule-polymer blend organic thin-film transistors with hole mobility greater than 5 cm 2/Vs

    KAUST Repository

    Smith, Jeremy N.; Zhang, Weimin; Sougrat, Rachid; Zhao, Kui; Li, Ruipeng; Cha, Dong Kyu; Amassian, Aram; Heeney, Martin J.; McCulloch, Iain A.; Anthopoulos, Thomas D.

    2012-01-01

    Using phase-separated organic semiconducting blends containing a small molecule, as the hole transporting material, and a conjugated amorphous polymer, as the binder material, we demonstrate solution-processed organic thin-film transistors with superior performance characteristics that include; hole mobility >5 cm 2/Vs, current on/off ratio ≥10 6 and narrow transistor parameter spread. These exceptional characteristics are attributed to the electronic properties of the binder polymer and the advantageous nanomorphology of the blend film. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Solution-processed small molecule-polymer blend organic thin-film transistors with hole mobility greater than 5 cm 2/Vs

    KAUST Repository

    Smith, Jeremy N.

    2012-04-10

    Using phase-separated organic semiconducting blends containing a small molecule, as the hole transporting material, and a conjugated amorphous polymer, as the binder material, we demonstrate solution-processed organic thin-film transistors with superior performance characteristics that include; hole mobility >5 cm 2/Vs, current on/off ratio ≥10 6 and narrow transistor parameter spread. These exceptional characteristics are attributed to the electronic properties of the binder polymer and the advantageous nanomorphology of the blend film. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Beyond simple small-angle X-ray scattering: developments in online complementary techniques and sample environments

    Directory of Open Access Journals (Sweden)

    Wim Bras

    2014-11-01

    Full Text Available Small- and wide-angle X-ray scattering (SAXS, WAXS are standard tools in materials research. The simultaneous measurement of SAXS and WAXS data in time-resolved studies has gained popularity due to the complementary information obtained. Furthermore, the combination of these data with non X-ray based techniques, via either simultaneous or independent measurements, has advanced understanding of the driving forces that lead to the structures and morphologies of materials, which in turn give rise to their properties. The simultaneous measurement of different data regimes and types, using either X-rays or neutrons, and the desire to control parameters that initiate and control structural changes have led to greater demands on sample environments. Examples of developments in technique combinations and sample environment design are discussed, together with a brief speculation about promising future developments.

  10. On the stability of non-supersymmetric supergravity solutions

    Science.gov (United States)

    Imaanpur, Ali; Zameni, Razieh

    2017-09-01

    We examine the stability of some non-supersymmetric supergravity solutions that have been found recently. The first solution is AdS5 ×M6, for M6 an stretched CP3. We consider breathing and squashing mode deformations of the metric, and find that the solution is stable against small fluctuations of this kind. Next we consider type IIB solution of AdS2 ×M8, where the compact space is a U (1) bundle over N (1 , 1). We study its stability under the deformation of M8 and the 5-form flux. In this case we also find that the solution is stable under small fluctuation modes of the corresponding deformations.

  11. On the stability of non-supersymmetric supergravity solutions

    Directory of Open Access Journals (Sweden)

    Ali Imaanpur

    2017-09-01

    Full Text Available We examine the stability of some non-supersymmetric supergravity solutions that have been found recently. The first solution is AdS5×M6, for M6 an stretched CP3. We consider breathing and squashing mode deformations of the metric, and find that the solution is stable against small fluctuations of this kind. Next we consider type IIB solution of AdS2×M8, where the compact space is a U(1 bundle over N(1,1. We study its stability under the deformation of M8 and the 5-form flux. In this case we also find that the solution is stable under small fluctuation modes of the corresponding deformations.

  12. A combined approach of generalized additive model and bootstrap with small sample sets for fault diagnosis in fermentation process of glutamate.

    Science.gov (United States)

    Liu, Chunbo; Pan, Feng; Li, Yun

    2016-07-29

    Glutamate is of great importance in food and pharmaceutical industries. There is still lack of effective statistical approaches for fault diagnosis in the fermentation process of glutamate. To date, the statistical approach based on generalized additive model (GAM) and bootstrap has not been used for fault diagnosis in fermentation processes, much less the fermentation process of glutamate with small samples sets. A combined approach of GAM and bootstrap was developed for the online fault diagnosis in the fermentation process of glutamate with small sample sets. GAM was first used to model the relationship between glutamate production and different fermentation parameters using online data from four normal fermentation experiments of glutamate. The fitted GAM with fermentation time, dissolved oxygen, oxygen uptake rate and carbon dioxide evolution rate captured 99.6 % variance of glutamate production during fermentation process. Bootstrap was then used to quantify the uncertainty of the estimated production of glutamate from the fitted GAM using 95 % confidence interval. The proposed approach was then used for the online fault diagnosis in the abnormal fermentation processes of glutamate, and a fault was defined as the estimated production of glutamate fell outside the 95 % confidence interval. The online fault diagnosis based on the proposed approach identified not only the start of the fault in the fermentation process, but also the end of the fault when the fermentation conditions were back to normal. The proposed approach only used a small sample sets from normal fermentations excitements to establish the approach, and then only required online recorded data on fermentation parameters for fault diagnosis in the fermentation process of glutamate. The proposed approach based on GAM and bootstrap provides a new and effective way for the fault diagnosis in the fermentation process of glutamate with small sample sets.

  13. Small angle X-ray scattering from protein in solution

    International Nuclear Information System (INIS)

    Souza, C.F. de; Torriani, I.L.

    1988-01-01

    In this work we report experiments performed with giant respiratory proteins from annelids. X-ray scattering data were obtained both by the use of conventional rotating anod source and synchotron radiation. Data from solutions with several protein concentrations were analyzed. (A.C.A.S.) [pt

  14. Indium flotation from hydrometallurgical solutions

    International Nuclear Information System (INIS)

    Sviridov, V.V.; Mal'tsev, G.I.; Petryakova, N.K.; Gomzikov, A.I.

    1980-01-01

    The principal possibility of flotation of indium small quantities (10 -4 gxion/l) is established from sulphuric-acid solutions of leaching converter dusts of the copper melting production in the form of complex compounds with sodium hexametaphosphate and cation-active nitrogen-containing surfactants. It is shown that the flotation process effectiveness is determined by the molar ratio of hexametaphosphate and collector introduced into the solution, solution oxidity and surfactant nature

  15. Complex solutions for generalised fitzhughnagumo equation

    International Nuclear Information System (INIS)

    Neirameh, A.

    2014-01-01

    During present investigation, a direct algebraic method on complex solutions of nonlinear partial differential equation is developed and tested in the case of generalized Burgers-Huxley equation. The proposed scheme can be used in a wide class of nonlinear reaction-diffusion equations. These calculations demonstrate that the accuracy of the direct algebraic solutions is quite high even in the case of a small number of grid points. This method is a very reliable, simple, small computation costs, flexible, and convenient alternative method. (author)

  16. Efficient solution-processed small molecule: Cadmium selenide quantum dot bulk heterojunction solar cells

    International Nuclear Information System (INIS)

    Gupta, Vinay; Upreti, Tanvi; Chand, Suresh

    2013-01-01

    We report bulk heterojunction solar cells based on blends of solution-processed small molecule [7,7′-(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b′]dithiophene-2,6-diyl) bis(6-fluoro-4-(5′-hexyl-[2,2′-bithiophen]-5yl)benzo[c] [1,2,5] thiadiazole)] p-DTS(FBTTh 2 ) 2 : Cadmium Selenide (CdSe) (70:30, 60:40, 50:50, and 40:60) in the device configuration: Indium Tin Oxide /poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/p-DTS(FBTTh 2 ) 2 : CdSe/Ca/Al. The optimized ratio of p-DTS(FBTTh 2 ) 2 :CdSe::60:40 leads to a short circuit current density (J sc ) = 5.45 mA/cm 2 , open circuit voltage (V oc ) = 0.727 V, and fill factor (FF) = 51%, and a power conversion efficiency = 2.02% at 100 mW/cm 2 under AM1.5G illumination. The J sc and FF are sensitive to the ratio of p-DTS(FBTTh 2 ) 2 :CdSe, which is a crucial factor for the device performance

  17. Effect of peritoneal lavage solution temperature on body temperature in anaesthetised cats and small dogs.

    Science.gov (United States)

    Barnes, D C; Leece, E A; Trimble, T A; Demetriou, J L

    2017-05-20

    A prospective, randomised, non-blinded, clinical study to assess the effect of peritoneal lavage using warmed fluid on body temperature in anesthetised cats and dogs of less than 10 kg body mass undergoing coeliotomy. A standardised anaesthetic protocol was used. Oesophageal and rectal temperatures were measured at various time points. At the end of surgery, group 1 patients (n=10) were lavaged with 200 ml/kg sterile isotonic saline at 34±1°C and group 2 (n=10) at 40±1°C. Groups were similar with respect to age, mass, body condition and surgical incision length. Duration of anaesthesia, surgical procedures and peritoneal lavage was similar between groups. Linear regression showed no significant change in oesophageal temperature during the lavage period for group 1 (P=0.64), but a significant increase for group 2 patients (Ptemperature changes of -0.5°C (from (36.3°C to 35.9°C) and +0.9°C (from 35.4°C to 36.3°C), respectively. Similar results were found for rectal temperature, with mean changes of -0.5°C and +0.8°C (P=0.922 and 0.045), respectively. The use of isotonic crystalloid solution for peritoneal lavage at a temperature of 40±1°C significantly warms small animal patients, when applied in a clinical setting, compared with lavage solution at 34±1°C. British Veterinary Association.

  18. Gravimetric and volumetric approaches adapted for hydrogen sorption measurements with in situ conditioning on small sorbent samples

    International Nuclear Information System (INIS)

    Poirier, E.; Chahine, R.; Tessier, A.; Bose, T.K.

    2005-01-01

    We present high sensitivity (0 to 1 bar, 295 K) gravimetric and volumetric hydrogen sorption measurement systems adapted for in situ sample conditioning at high temperature and high vacuum. These systems are designed especially for experiments on sorbents available in small masses (mg) and requiring thorough degassing prior to sorption measurements. Uncertainty analysis from instrumental specifications and hydrogen absorption measurements on palladium are presented. The gravimetric and volumetric systems yield cross-checkable results within about 0.05 wt % on samples weighing from (3 to 25) mg. Hydrogen storage capacities of single-walled carbon nanotubes measured at 1 bar and 295 K with both systems are presented

  19. The Safe and Efficient Evaporation of a Solvent from Solution

    Science.gov (United States)

    Mahon, Andrew R.

    1997-02-01

    The process of evaporating a solvent from a solution can cause problems for many students. By using a water-vacuum aspirator, backflashes of water can flood the sample tube and be detrimental to the experiment. This type of apparatus can also cause problems by drawing the solution it is evaporating back into the vacuum hose, causing the student to lose part or all of the products of their experiment. Macroscale and Microscale Organic Experiments, 2nd edition (1), suggested two techniques to dissolve solvents from a mixture. It suggested blowing a stream of air over the solution from a Pasteur pipet, or attaching a Pasteur pipet to an aspirator and drawing air over the surface of the liquid. Again, the danger of blowing air over the solution leaves the risk of splattering the solution, and drawing air over the surface of the liquid as described further endangers the products of the experiment through the risk of sucking the products up into the pipet aspirator. In an effort to eliminate these problems, a new technique has been developed. By inverting an ordinary 200-mL vacuum flask and pulling a steady current of air from the vacuum apparatus through it, any type of small container can be placed under it, allowing the solvent to be evaporated in a steady, mistake-free manner . By evaporating the solvent from the container that the products will be submitted in, no sample is lost through the process of transferring it from a vacuum flask or beaker to the final container.

  20. Small angle neutron scattering (SANS) study of gastric mucin solutions

    Science.gov (United States)

    Hong, Z.; Bansil, R.; Waigh, T.; Turner, B.; Bhaskar, K. R.; Afdhal, N.; Lal, J.

    2002-03-01

    We report the first results from a SANS study of purified porcine gastric mucin solutions in D2O. The ability of this glycoprotein to protect the stomach epithelium from acid damage, may be due to a pH dependent conformational transition which leads to gelation at low pH Cao et. al. (Biophysical. J. 76, 1250, 1999). SANS measurements were made over the concentration range of 1 -15 mg/ml at pH 7, 4 and 2. The data indicate that at pH 7 the excluded volume exponent is 1.7, characteristic of swollen chains whereas at pH 2 this exponent increases to 2, indicating theta or poor solvent conditions, consistent with the hydrophobic interactions increasing at lower pH. From a Guinier analysis of the 1mg/ml data at low q's (0.003- 0.007 Å-1) we estimate the cross section radius of the effective cylinder to be 23nm and its length as 96nm in an unbuffered sample, i.e. close to pH 7. In the intermediate q-range (0.01 -0.1Å-1) at pH 7 a fit to the Debye chain gives radius of gyration Rg of 16nm. Mucin is best modelled as an elongated micelle with a cylindrical or worm-like chain to represent the protein core and the sugar chains forming the corona. Results of such calculations will be presented.

  1. Inverse Gaussian model for small area estimation via Gibbs sampling

    African Journals Online (AJOL)

    We present a Bayesian method for estimating small area parameters under an inverse Gaussian model. The method is extended to estimate small area parameters for finite populations. The Gibbs sampler is proposed as a mechanism for implementing the Bayesian paradigm. We illustrate the method by application to ...

  2. Small-angle scattering at a pulsed neutron source: comparison with a steady-state reactor

    Energy Technology Data Exchange (ETDEWEB)

    Borso, C S; Carpenter, J M; Williamson, F S; Holmblad, G L; Mueller, M H; Faber, J Jr; Epperson, J E; Danyluk, S S [Argonne National Lab., IL (USA)

    1982-08-01

    A time-of-flight small-angle diffractometer employing seven tapered collimator elements and a two-dimensional gas proportional counter was successfully utilized to collect small-angle scattering data from a solution sample of the lipid salt cetylpyridinium chloride, C/sub 21/H/sub 38/N/sup +/.Cl/sup -/, at the Argonne National Laboratory prototype pulsed spallation neutron source, ZING-P'. Comparison of the small-angle scattering observed from the same compound at the University of Missouri Research Reactor corroborated the ZING-P' results. The results are used to compare the neutron flux available from the ZING-P' source relative to the well characterized University of Missouri source. Calculations based on experimentally determined parameters indicated the time-averaged rate of detected neutrons at the ZING-P' pulsed spallation source to have been at least 33% higher than the steady-state count rate from the same sample. Differences between time-of-flight techniques and conventional steady-state techniques are discussed.

  3. Small-kernel constrained-least-squares restoration of sampled image data

    Science.gov (United States)

    Hazra, Rajeeb; Park, Stephen K.

    1992-10-01

    Constrained least-squares image restoration, first proposed by Hunt twenty years ago, is a linear image restoration technique in which the restoration filter is derived by maximizing the smoothness of the restored image while satisfying a fidelity constraint related to how well the restored image matches the actual data. The traditional derivation and implementation of the constrained least-squares restoration filter is based on an incomplete discrete/discrete system model which does not account for the effects of spatial sampling and image reconstruction. For many imaging systems, these effects are significant and should not be ignored. In a recent paper Park demonstrated that a derivation of the Wiener filter based on the incomplete discrete/discrete model can be extended to a more comprehensive end-to-end, continuous/discrete/continuous model. In a similar way, in this paper, we show that a derivation of the constrained least-squares filter based on the discrete/discrete model can also be extended to this more comprehensive continuous/discrete/continuous model and, by so doing, an improved restoration filter is derived. Building on previous work by Reichenbach and Park for the Wiener filter, we also show that this improved constrained least-squares restoration filter can be efficiently implemented as a small-kernel convolution in the spatial domain.

  4. Health indicators: eliminating bias from convenience sampling estimators.

    Science.gov (United States)

    Hedt, Bethany L; Pagano, Marcello

    2011-02-28

    Public health practitioners are often called upon to make inference about a health indicator for a population at large when the sole available information are data gathered from a convenience sample, such as data gathered on visitors to a clinic. These data may be of the highest quality and quite extensive, but the biases inherent in a convenience sample preclude the legitimate use of powerful inferential tools that are usually associated with a random sample. In general, we know nothing about those who do not visit the clinic beyond the fact that they do not visit the clinic. An alternative is to take a random sample of the population. However, we show that this solution would be wasteful if it excluded the use of available information. Hence, we present a simple annealing methodology that combines a relatively small, and presumably far less expensive, random sample with the convenience sample. This allows us to not only take advantage of powerful inferential tools, but also provides more accurate information than that available from just using data from the random sample alone. Copyright © 2011 John Wiley & Sons, Ltd.

  5. Determination of Organic Pollutants in Small Samples of Groundwaters by Liquid-Liquid Extraction and Capillary Gas Chromatography

    DEFF Research Database (Denmark)

    Harrison, I.; Leader, R.U.; Higgo, J.J.W.

    1994-01-01

    A method is presented for the determination of 22 organic compounds in polluted groundwaters. The method includes liquid-liquid extraction of the base/neutral organics from small, alkaline groundwater samples, followed by derivatisation and liquid-liquid extraction of phenolic compounds after neu...... neutralisation. The extracts were analysed by capillary gas chromatography. Dual detection by flame Ionisation and electron capture was used to reduce analysis time....

  6. Present status of NMCC and sample preparation method for bio-samples

    International Nuclear Information System (INIS)

    Futatsugawa, S.; Hatakeyama, S.; Saitou, S.; Sera, K.

    1993-01-01

    In NMCC(Nishina Memorial Cyclotron Center) we are doing researches on PET of nuclear medicine (Positron Emission Computed Tomography) and PIXE analysis (Particle Induced X-ray Emission) using a small cyclotron of compactly designed. The NMCC facilities have been opened to researchers of other institutions since April 1993. The present status of NMCC is described. Bio-samples (medical samples, plants, animals and environmental samples) have mainly been analyzed by PIXE in NMCC. Small amounts of bio-samples for PIXE are decomposed quickly and easily in a sealed PTFE (polytetrafluoroethylene) vessel with a microwave oven. This sample preparation method of bio-samples also is described. (author)

  7. Use of aspiration method for collecting brain samples for rabies diagnosis in small wild animals.

    Science.gov (United States)

    Iamamoto, K; Quadros, J; Queiroz, L H

    2011-02-01

    In developing countries such as Brazil, where canine rabies is still a considerable problem, samples from wildlife species are infrequently collected and submitted for screening for rabies. A collaborative study was established involving environmental biologists and veterinarians for rabies epidemiological research in a specific ecological area located at the Sao Paulo State, Brazil. The wild animals' brains are required to be collected without skull damage because the skull's measurements are important in the identification of the captured animal species. For this purpose, samples from bats and small mammals were collected using an aspiration method by inserting a plastic pipette into the brain through the magnum foramen. While there is a progressive increase in the use of the plastic pipette technique in various studies undertaken, it is also appreciated that this method could foster collaborative research between wildlife scientists and rabies epidemiologists thus improving rabies surveillance. © 2009 Blackwell Verlag GmbH.

  8. An determination of man-made γ-emitting radionuclides in coal fly ash and standard solution

    International Nuclear Information System (INIS)

    Xu Cuihua; Zhou Qiang

    2004-01-01

    We participated an international comparison on the determination of man-made γ-emitting radionuclides in coal fly ash and in standard solution organized by the Analytical Quality Control Service of the IAEA in 2002. The sample was dispensed in 100.0 ± 0.1 g aliquots in plastic container and was spiked with known amounts of certified standard γ-emitting radionuclides 54 Mn, 57 Co, 60 Co, 65 Zn, 88 Y, 134 Cs, 137 Cs and 241 Am. The determination of the anthropogenic )γ-emitting radionuclides in the test samples was carried out with an ORTEC gamma-ray spectrometry system coupled with a HPGe detector with resolution of 1.75 keV and relative efficiency of 55% for 137 Cs, located in a 10 cm thick lead container. The energy and efficiency calibration were with home-made volume calibration sources containing some of the radionuclides to be analyzed. The analysis procedure is described elsewhere. Table 1 lists the results of the determination and the comparisons with IAEA reference data and evaluation. Overall our results are agreeable in ±8.6% with the IAEA reference data, except for 60 Co. The differences for 60 Co was -10.8%. It may be caused by the 60 Co calibration source made with residual of quiet old standard solution. The difference for 241 Am is due to self-absorption in the fly ash sample. This bias was small for the solution sample. For standard solution sample, the results are agreeable within ±3.7% for all radionuclides except for 60 Co, being 12%. (authors)

  9. Transabdominal ultrasonography of the small bowel after oral administration of a non-absorbable anechoic solution: Comparison with barium enteroclysis

    Energy Technology Data Exchange (ETDEWEB)

    Cittadini, Giuseppe; Giasotto, Veronica; Garlaschi, Giacomo; De Cicco, Enzo; Gallo, Alessandra; Cittadini, Giorgio

    2001-03-01

    AIM: The aim of this study was to determine if oral administration of a non-absorbable anechoic solution conveys any benefit during abdominal ultrasound (US), with special reference to its accuracy. MATERIALS AND METHODS: Fifty-three adult out-patients scheduled for small bowel barium enema (SBE) were included. The day before SBE all patients underwent abdominal US before and after oral administration of an isotonic non-absorbable electrolyte solution containing polyethylene glycol (PEG-ELS). Sensitivity and specificity were evaluated using SBE as a gold standard. RESULTS: After ingestion of PEG-ELS satisfactory distension of the intestinal lumen was obtained (11-25 mm) with sequential visualization of jejunoileal loops in 30.9 {+-} 17.3 min. In 15 out of 53 cases both US and SBE showed bowel changes characteristic of Crohn's disease. In three out of 53 cases both US and SBE showed neoplasms. In one out of 53 cases US was negative, SBE positive for local nodularity and ulcerations typical of Crohn's disease. In one out of 53 cases US was negative, SBE positive for macronodularity consistent with coeliac disease. In five out of 53 cases US was negative, while SBE was positive for mininodularity expressive of lymphoid hyperplasia. In 28 out of 53 cases both examinations were negative. CONCLUSION: PEG-ELS administration allows a thorough US investigation of the small bowel, with fair sensitivity (72%) and excellent specificity (100%). False negative findings are mainly due to lymphoid hyperplasia, a feature of uncertain significance in adults. Cittadini G. et al.(2001)

  10. Small Business Demand Response with Communicating Thermostats: SMUD's Summer Solutions Research Pilot

    Energy Technology Data Exchange (ETDEWEB)

    Herter, Karen; Wayland, Seth; Rasin, Josh

    2009-09-25

    This report documents a field study of 78 small commercial customers in the Sacramento Municipal Utility District service territory who volunteered for an integrated energy-efficiency/demand-response (EE-DR) program in the summer of 2008. The original objective for the pilot was to provide a better understanding of demand response issues in the small commercial sector. Early findings justified a focus on offering small businesses (1) help with the energy efficiency of their buildings in exchange for occasional load shed, and (2) a portfolio of options to meet the needs of a diverse customer sector. To meet these expressed needs, the research pilot provided on-site energy efficiency advice and offered participants several program options, including the choice of either a dynamic rate or monthly payment for air-conditioning setpoint control. An analysis of hourly load data indicates that the offices and retail stores in our sample provided significant demand response, while the restaurants did not. Thermostat data provides further evidence that restaurants attempted to precool and reduce AC service during event hours, but were unable to because their air-conditioning units were undersized. On a 100 F reference day, load impacts of all participants during events averaged 14%, while load impacts of office and retail buildings (excluding restaurants) reached 20%. Overall, pilot participants including restaurants had 2007-2008 summer energy savings of 20% and bill savings of 30%. About 80% of participants said that the program met or surpassed their expectations, and three-quarters said they would probably or definitely participate again without the $120 participation incentive. These results provide evidence that energy efficiency programs, dynamic rates and load control programs can be used concurrently and effectively in the small business sector, and that communicating thermostats are a reliable tool for providing air-conditioning load shed and enhancing the ability

  11. Systematic studies of small scintillators for new sampling calorimeter

    International Nuclear Information System (INIS)

    Jacosalem, E.P.; Sanchez, A.L.C.; Bacala, A.M.; Iba, S.; Nakajima, N.; Ono, H.; Miyata, H.

    2007-01-01

    A new sampling calorimeter using very thin scintillators and the multi-pixel photon counter (MPPC) has been proposed to produce better position resolution for the international linear collider (ILC) experiment. As part of this R and D study, small plastic scintillators of different sizes, thickness and wrapping reflectors are systematically studied. The scintillation light due to beta rays from a collimated 90 Sr source are collected from the scintillator by wavelength-shifting (WLS) fiber and converted into electrical signals at the PMT. The wrapped scintillator that gives the best light yield is determined by comparing the measured pulse height of each 10 x 40 x 2 mm strip scintillator covered with 3M reflective mirror film, teflon, white paint, black tape, gold, aluminum and white paint+teflon. The pulse height dependence on position, length and thickness of the 3M reflective mirror film and teflon wrapped scintillators are measured. Results show that the 3M radiant mirror film-wrapped scintillator has the greatest light yield with an average of 9.2 photoelectrons. It is observed that light yield slightly increases with scintillator length, but increases to about 100% when WLS fiber diameter is increased from 1.0 mm to 1.6 mm. The position dependence measurement along the strip scintillator showed the uniformity of light transmission from the sensor to the PMT. A dip across the strip is observed which is 40% of the maximum pulse height. The block type scintillator pulse height, on the other hand, is found to be almost proportional to scintillator thickness. (author)

  12. Efficient parallel implementations of QM/MM-REMD (quantum mechanical/molecular mechanics-replica-exchange MD) and umbrella sampling: isomerization of H2O2 in aqueous solution.

    Science.gov (United States)

    Fedorov, Dmitri G; Sugita, Yuji; Choi, Cheol Ho

    2013-07-03

    An efficient parallel implementation of QM/MM-based replica-exchange molecular dynamics (REMD) as well as umbrella samplings techniques was proposed by adopting the generalized distributed data interface (GDDI). Parallelization speed-up of 40.5 on 48 cores was achieved, making our QM/MM-MD engine a robust tool for studying complex chemical dynamics in solution. They were comparatively used to study the torsional isomerization of hydrogen peroxide in aqueous solution. All results by QM/MM-REMD and QM/MM umbrella sampling techniques yielded nearly identical potentials of mean force (PMFs) regardless of the particular QM theories for solute, showing that the overall dynamics are mainly determined by solvation. Although the entropic penalty of solvent rearrangements exists in cisoid conformers, it was found that both strong intermolecular hydrogen bonding and dipole-dipole interactions preferentially stabilize them in solution, reducing the torsional free-energy barrier at 0° by about 3 kcal/mol as compared to that in gas phase.

  13. Dried blood spots on carboxymethyl cellulose sheets: Rapid sample preparation based on dissolution and precipitation

    DEFF Research Database (Denmark)

    Skoglund Ask, Kristine; Pedersen-Bjergaard, Stig; Gjelstad, Astrid

    2016-01-01

    This short communication describes the use of carboxymethyl cellulose sheets as sampling material for dried blood spots. Whole blood, spiked with quetiapine, a hydrophobic and basic small molecule drug substance, was spotted on the sheet and subsequently dried. The dried spot was then almost...... completely dissolved in acidified aqueous solution. It was shown that the dissolved polymer, together with major blood components can easily be precipitated and removed with acetonitrile. The presented sampling on a water-soluble biopolymer derivative followed by precipitation resulted in a simple protocol...

  14. Comparative exploration of hydrogen sulfide and water transmembrane free energy surfaces via orthogonal space tempering free energy sampling.

    Science.gov (United States)

    Lv, Chao; Aitchison, Erick W; Wu, Dongsheng; Zheng, Lianqing; Cheng, Xiaolin; Yang, Wei

    2016-03-05

    Hydrogen sulfide (H2 S), a commonly known toxic gas compound, possesses unique chemical features that allow this small solute molecule to quickly diffuse through cell membranes. Taking advantage of the recent orthogonal space tempering (OST) method, we comparatively mapped the transmembrane free energy landscapes of H2 S and its structural analogue, water (H2 O), seeking to decipher the molecular determinants that govern their drastically different permeabilities. As revealed by our OST sampling results, in contrast to the highly polar water solute, hydrogen sulfide is evidently amphipathic, and thus inside membrane is favorably localized at the interfacial region, that is, the interface between the polar head-group and nonpolar acyl chain regions. Because the membrane binding affinity of H2 S is mainly governed by its small hydrophobic moiety and the barrier height inbetween the interfacial region and the membrane center is largely determined by its moderate polarity, the transmembrane free energy barriers to encounter by this toxic molecule are very small. Moreover when H2 S diffuses from the bulk solution to the membrane center, the above two effects nearly cancel each other, so as to lead to a negligible free energy difference. This study not only explains why H2 S can quickly pass through cell membranes but also provides a practical illustration on how to use the OST free energy sampling method to conveniently analyze complex molecular processes. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  15. Exploring manufacturing solutions for SMEs

    DEFF Research Database (Denmark)

    Radziwon, Agnieszka; Blichfeldt, Henrik; Bilberg, Arne

    This exploratory study provides an overview over current state of manufacturing solutions in small and medium sized enterprises (SMEs) in region of Southern Denmark. Building on manufacturing paradigms, this paper reveals relevant aspects for the development and implementation of improving SMEs...... of manufacturing solutions, which are required to increase their competitiveness and assure sustainable growth....

  16. Reduced detection by Ziehl-Neelsen method of acid-fast bacilli in sputum samples preserved in cetylpyridinium chloride solution.

    Science.gov (United States)

    Selvakumar, N; Sudhamathi, S; Duraipandian, M; Frieden, T R; Narayanan, P R

    2004-02-01

    Twelve health facilities implementing the DOTS strategy, and the Tuberculosis Research Centre (TRC), Chennai, India. To determine the detection rates using Ziehl-Neelsen (ZN) and auramine-phenol to stain acid-fast bacilli (AFB) in sputum samples stored in cetylpyridinium chloride (CPC) solution. Two smears were prepared from each of 988 sputum samples collected in CPC and randomly allocated, one to ZN and the other to auramine-phenol staining. All samples were processed for culture of Mycobacterium tuberculosis. A significantly higher proportion of samples were negative using the ZN method compared to the auramine-phenol method (74.5% vs. 61.8%, McNamara's paired chi2 test; P < 0.001). Among 377 samples that were positive using auramine-phenol, 44% were negative using ZN. There were more culture-positive, smear-negative samples in ZN (52.7%) than in auramine-phenol (30%); the difference attained statistical significance (McNemar's paired chi2 test; P < 0.00004). Using ZN, of the 104 smears made immediately after collection, 52 were positive for AFB, of which only 35 (67.3%) were positive after storage in CPC; the reduction in the number of positive smears attained statistical significance (McNemar's paired chi2 test; P = 0.004). Detection of AFB in sputum samples preserved in CPC is significantly reduced using ZN staining.

  17. Detection of small conformational changes of proteins by small-angle scattering

    International Nuclear Information System (INIS)

    Durchschlag, H.; Purr, G.; Zipper, P.; Wilfing, R.

    1991-01-01

    In the past the technique of small-angle scattering has been a powerful tool for studying conformational changes of protein which occur, for example, upon binding with ligands. Results obtained by different authors from X-ray and neutron experiments on a variety of proteins and under various conditions have been compiled. This offers the possibility of comparing the extent of changes in the molecular parameters investigated (e.g. change of the radius of gyration). Problems encountered with the detection of small changes are discussed. As an example, conformational changes of the enzyme citrate synthase upon substrate binding (oxaloacetate) are presented. X-ray crystallography had already found distinct changes between open and closed forms of the enzyme. Small-angle X-ray scattering studies registered slight changes of some parameters in solution. These changes could be paralleled with the results of other solution techniques (UV absorption, fluorescence and circular dichroism spectroscopy, analytical ultracentrifugation). The results found for citrate synthase are also compared with previous findings for malate synthase, an enzyme of similar enzymatic function. Above all, this study shows that care has to be taken when studying small conformational changes. It is absolutely necessary to use different methods and conditions and to study the problem from different points of view to avoid pitfalls. (orig.)

  18. Mutational status of synchronous and metachronous tumor samples in patients with metastatic non-small-cell lung cancer

    International Nuclear Information System (INIS)

    Quéré, Gilles; Descourt, Renaud; Robinet, Gilles; Autret, Sandrine; Raguenes, Odile; Fercot, Brigitte; Alemany, Pierre; Uguen, Arnaud; Férec, Claude; Quintin-Roué, Isabelle; Le Gac, Gérald

    2016-01-01

    Despite reported discordance between the mutational status of primary lung cancers and their metastases, metastatic sites are rarely biopsied and targeted therapy is guided by genetic biomarkers detected in the primary tumor. This situation is mostly explained by the apparent stability of EGFR-activating mutations. Given the dramatic increase in the range of candidate drugs and high rates of drug resistance, rebiopsy or liquid biopsy may become widespread. The purpose of this study was to test genetic biomarkers used in clinical practice (EGFR, ALK) and candidate biomarkers identified by the French National Cancer Institute (KRAS, BRAF, PIK3CA, HER2) in patients with metastatic non-small-cell lung cancer for whom two tumor samples were available. A retrospective study identified 88 tumor samples collected synchronously or metachronously, from the same or two different sites, in 44 patients. Mutation analysis used SNaPshot (EGFR, KRAS, BRAF missense mutations), pyrosequencing (EGFR and PIK3CA missense mutations), sizing assays (EGFR and HER2 indels) and IHC and/or FISH (ALK rearrangements). About half the patients (52 %) harbored at least one mutation. Five patients had an activating mutation of EGFR in both the primary tumor and the metastasis. The T790M resistance mutation was detected in metastases in 3 patients with acquired resistance to EGFR tyrosine kinase inhibitors. FISH showed discordance in ALK status between a small biopsy sample and the surgical specimen. KRAS mutations were observed in 36 % of samples, six patients (14 %) having discordant genotypes; all discordances concerned sampling from different sites. Two patients (5 %) showed PI3KCA mutations. One metastasis harbored both PI3KCA and KRAS mutations, while the synchronously sampled primary tumor was mutation free. No mutations were detected in BRAF and HER2. This study highlighted noteworthy intra-individual discordance in KRAS mutational status, whereas EGFR status was stable. Intratumoral

  19. Enhancement of Performance and Mechanism Studies of All-Solution Processed Small-Molecule based Solar Cells with an Inverted Structure.

    Science.gov (United States)

    Long, Guankui; Wu, Bo; Yang, Xuan; Kan, Bin; Zhou, Ye-Cheng; Chen, Li-Chuan; Wan, Xiangjian; Zhang, Hao-Li; Sum, Tze Chien; Chen, Yongsheng

    2015-09-30

    Both solution-processed polymers and small molecule based solar cells have achieved PCEs over 9% with the conventional device structure. However, for the practical applications of photovoltaic technology, further enhancement of both device performance and stability are urgently required, particularly for the inverted structure devices, since this architecture will probably be most promising for the possible coming commercialization. In this work, we have fabricated both conventional and inverted structure devices using the same small molecular donor/acceptor materials and compared the performance of both device structures, and found that the inverted structure based device gave significantly improved performance, the highest PCE so far for inverted structure based device using small molecules as the donor. Furthermore, the inverted device shows a remarkable stability with almost no obvious degradation after three months. Systematic device physics and charge generation dynamics studies, including optical simulation, light-intensity-dependent current-voltage experiments, photocurrent density-effective voltage analyses, transient absorption measurements, and electrical simulations, indicate that the significantly enhanced performance using inverted device is ascribed to the increasing of Jsc compared to the conventional device, which in turn is mainly attributed to the increased absorption of photons in the active layers, rather than the reduced nongeminate recombination.

  20. Analytic Solutions and Resonant Solutions of Hyperbolic Partial Differential Equations

    Science.gov (United States)

    Wagenmaker, Timothy Roger

    This dissertation contains two main subject areas. The first deals with solutions to the wave equation Du/Dt + a Du/Dx = 0, where D/Dt and D/Dx represent partial derivatives and a(t,x) is real valued. The question I studied, which arises in control theory, is whether solutions which are real analytic with respect to the time variable are dense in the space of all solutions. If a is real analytic in t and x, the Cauchy-Kovalevsky Theorem implies that the solutions real analytic in t and x are dense, since it suffices to approximate the initial data by polynomials. The same positive result is valid when a is continuously differentiable and independent of t. This is proved by regularization in time. The hypothesis that a is independent of t cannot be replaced by the weaker assumption that a is real analytic in t, even when it is infinitely smooth. I construct a(t,x) for which the solutions which are analytic in time are automatically periodic in time. In particular these solutions are not dense in the space of all solutions. The second area concerns the resonant interaction of oscillatory waves propagating in a compressible inviscid fluid. An asymptotic description given by Andrew Majda, Rodolfo Rosales, and Maria Schonbek (MRS) involves the genuinely nonlinear quasilinear hyperbolic system Du/Dt + D(uu/2)/Dt + v = 0, Dv/Dt - D(vv/2)/Dt - u = 0. They performed many numerical simulations which indicated that small amplitude solutions of this system tend to evade shock formation, and conjectured that "smooth initial data with a sufficiently small amplitude never develop shocks throughout a long time interval of integration.". I proved that for smooth periodic U(x), V(x) and initial data u(0,x) = epsilonU(x), v(0,x) = epsilonV(x), the solution is smooth for time at least constant times | ln epsilon| /epsilon. This is longer than the lifetime order 1/ epsilon of the solution to the decoupled Burgers equations. The decoupled equation describes nonresonant interaction of

  1. Conformation and arrangement of polyelectrolytes in semi-diluted solution. A study by small angle neutrons scattering; Conformation et arrangement des polyelectrolytes en solution semi-diluee. Etude par diffusion des neutrons aux petits angles

    Energy Technology Data Exchange (ETDEWEB)

    Spiteri, M N

    1997-03-25

    Polyelectrolytes have particular physical and chemical properties and can thus be used for instance for petroleum production. Some of their microscopic properties have been studied in this work. With the particular zero average contrast technique, the small angle neutron scattering allows to directly know the form factors in semi-diluted solutions of polyelectrolytes where the chains are mixed. Another measure leads to the crystal structure. The electrostatic screen effects when salt is added in aqueous solutions of completely charged PSSNa solutions (f=1) (sodium polystyrene sulfonate) are studied. It seems that the chains take a vermiform conformation. Their persistence length varies as I{sup -1/3} (I is the ionic force). The hydrophobicity effects in partially charged PSSNa solutions (f<1) are given too. They lead to a progressive collapse of the chains when their charge rates decrease. The screen and condensation effects when the charge rate f of the PSSNa (f>f(Manning)) varies in a polar solvent (DMSO) are studied. The vermiform chains have the same persistence length (for each f) which varies as I{sup -1/4}. Lastly, the f variation effects in the case of a weakly charged hydrophilic poly-ion (f

  2. Complete solution of the modified Cherry oscillator problem

    International Nuclear Information System (INIS)

    Pfirsch, D.

    1990-04-01

    In 1925, T.M. Cherry presented a simple example demonstrating that linear stability analysis will in general not be sufficient for finding out whether a system is stable or not with respect to small-amplitude perturbations. The example consisted of two nonlinearly coupled oscillators, one possessing positive energy, the other negative energy, with frequencies ω 1 =2ω 2 allowing third-order resonance. In a previous paper, the present author reformulated Cherry's example and then generalized it to three coupled oscillators corresponding to three-wave interaction in a continuum theory like that of Maxwell-Vlasov. Cherry was able to present a two-parameter solution set for his example which would, however, allow a four-parameter solution set, and a three-parameter solution set for the resonant three-oscillator case was obtained which, however, would allow a six-parameter solution set. Nonlinear instability could therefore be proven only for a very small part of the phase space of the oscillators. This paper now gives the complete solution for the three-oscillator case and shows that, except for a singular case, all initial conditions, especially those with arbitrarily small amplitudes, lead to explosive behaviour. This is true of the resonant case. The non-resonant oscillators can sometimes also become explosively unstable, but only if the initial amplitudes are not infinitesimally small. (orig.)

  3. Technical Note: New methodology for measuring viscosities in small volumes characteristic of environmental chamber particle samples

    Directory of Open Access Journals (Sweden)

    L. Renbaum-Wolff

    2013-01-01

    Full Text Available Herein, a method for the determination of viscosities of small sample volumes is introduced, with important implications for the viscosity determination of particle samples from environmental chambers (used to simulate atmospheric conditions. The amount of sample needed is < 1 μl, and the technique is capable of determining viscosities (η ranging between 10−3 and 103 Pascal seconds (Pa s in samples that cover a range of chemical properties and with real-time relative humidity and temperature control; hence, the technique should be well-suited for determining the viscosities, under atmospherically relevant conditions, of particles collected from environmental chambers. In this technique, supermicron particles are first deposited on an inert hydrophobic substrate. Then, insoluble beads (~1 μm in diameter are embedded in the particles. Next, a flow of gas is introduced over the particles, which generates a shear stress on the particle surfaces. The sample responds to this shear stress by generating internal circulations, which are quantified with an optical microscope by monitoring the movement of the beads. The rate of internal circulation is shown to be a function of particle viscosity but independent of the particle material for a wide range of organic and organic-water samples. A calibration curve is constructed from the experimental data that relates the rate of internal circulation to particle viscosity, and this calibration curve is successfully used to predict viscosities in multicomponent organic mixtures.

  4. Static, Mixed-Array Total Evaporation for Improved Quantitation of Plutonium Minor Isotopes in Small Samples

    Science.gov (United States)

    Stanley, F. E.; Byerly, Benjamin L.; Thomas, Mariam R.; Spencer, Khalil J.

    2016-06-01

    Actinide isotope measurements are a critical signature capability in the modern nuclear forensics "toolbox", especially when interrogating anthropogenic constituents in real-world scenarios. Unfortunately, established methodologies, such as traditional total evaporation via thermal ionization mass spectrometry, struggle to confidently measure low abundance isotope ratios (evaporation techniques as a straightforward means of improving plutonium minor isotope measurements, which have been resistant to enhancement in recent years because of elevated radiologic concerns. Results are presented for small sample (~20 ng) applications involving a well-known plutonium isotope reference material, CRM-126a, and compared with traditional total evaporation methods.

  5. Dynamics of dilute polymer solutions

    International Nuclear Information System (INIS)

    Nicholson, L.K.; Higgins, J.S.

    1980-01-01

    Neutrons scattered by nuclei undergoing slow motion e.g. the internal motion within polymer chains, lose or gain very small amounts of energy. It is therefore the quasi-elastic region of the neutron scattering spectrum which is of interest and in particular the time correlation function (or intermediate scattering law S(Q,t)) which is ideally required to define the motion. The neutron spin echo spectrometer (IN11) at the ILL facilitates the measurement of very small energy changes (down to 10 neV) on scattering from a sample, by changing and keeping track of neutron beam polarization non-parallel to the magnetic guide-field (1). The resultant neutron beam polarization, when normalized against a standard (totally elastic) scatterer is directly proportional to the cosine Fourier Transform of the scattering law S(Q,ω), which is to say the time correlation function is measured directly. Dilute solutions of deuterated polystyrene (PSD) and deuterated polytetrahydrofuran (PTDF) in carbon disulphide, and of their hydrogeneous counterparts (PSH and PTHF respectively) in deuterated benzene were investigated in the range 0.027 A -1 -1 , at 30 0 C. (orig./FKS)

  6. Optimization of palm oil extraction from Decanter cake of small crude palm oil mill by aqueous surfactant solution using RSM

    Science.gov (United States)

    Ahmadi Pirshahid, Shewa; Arirob, Wallop; Punsuvon, Vittaya

    2018-04-01

    The use of hexane to extract vegetable oil from oilseeds or seed cake is of growing concern due to its environmental impact such as its smelling and toxicity. In our method, used Response Surface Methodology (RSM) was applied to study the optimum condition of decanter cake obtained from small crude palm oil with aqueous surfactant solution. For the first time, we provide an optimum condition of preliminary study with decanter cake extraction to obtain the maximum of oil yield. The result from preliminary was further used in RSM study by using Central Composite Design (CCD) that consisted of thirty experiments. The effect of four independent variables: the concentration of Sodium Dodecyl Sulfate (SDS) as surfactant, temperature, the ratio by weight to volume of cake to surfactant solution and the amount of sodium chloride (NaCl) on dependent variables are studied. Data were analyzed using Design-Expert 8 software. The results showed that the optimum condition of decanter cake extraction were 0.016M of SDS solution concentration, 73°C of extraction temperature, 1:10 (g:ml) of the ratio of decanter cake to SDS solution and 2% (w/w) of NaCl amount. This condition gave 77.05% (w/w) oil yield. The chemical properties of the extracted palm oil from this aqueous surfactant extraction are further investigated compared with the hexane extraction. The obtained result showed that all properties of both extractions were nearly the same.

  7. A passive guard for low thermal conductivity measurement of small samples by the hot plate method

    International Nuclear Information System (INIS)

    Jannot, Yves; Godefroy, Justine; Degiovanni, Alain; Grigorova-Moutiers, Veneta

    2017-01-01

    Hot plate methods under steady state conditions are based on a 1D model to estimate the thermal conductivity, using measurements of the temperatures T 0 and T 1 of the two sides of the sample and of the heat flux crossing it. To be consistent with the hypothesis of the 1D heat flux, either a hot plate guarded apparatus is used, or the temperature is measured at the centre of the sample. On one hand the latter method can be used only if the ratio thickness/width of the sample is sufficiently low and on the other hand the guarded hot plate method requires large width samples (typical cross section of 0.6  ×  0.6 m 2 ). That is why both methods cannot be used for low width samples. The method presented in this paper is based on an optimal choice of the temperatures T 0 and T 1 compared to the ambient temperature T a , enabling the estimation of the thermal conductivity with a centered hot plate method, by applying the 1D heat flux model. It will be shown that these optimal values do not depend on the size or on the thermal conductivity of samples (in the range 0.015–0.2 W m −1 K −1 ), but only on T a . The experimental results obtained validate the method for several reference samples for values of the ratio thickness/width up to 0.3, thus enabling the measurement of the thermal conductivity of samples having a small cross-section, down to 0.045  ×  0.045 m 2 . (paper)

  8. Vertical Sampling Scales for Atmospheric Boundary Layer Measurements from Small Unmanned Aircraft Systems (sUAS

    Directory of Open Access Journals (Sweden)

    Benjamin L. Hemingway

    2017-09-01

    Full Text Available The lowest portion of the Earth’s atmosphere, known as the atmospheric boundary layer (ABL, plays an important role in the formation of weather events. Simple meteorological measurements collected from within the ABL, such as temperature, pressure, humidity, and wind velocity, are key to understanding the exchange of energy within this region, but conventional surveillance techniques such as towers, radar, weather balloons, and satellites do not provide adequate spatial and/or temporal coverage for monitoring weather events. Small unmanned aircraft, or aerial, systems (sUAS provide a versatile, dynamic platform for atmospheric sensing that can provide higher spatio-temporal sampling frequencies than available through most satellite sensing methods. They are also able to sense portions of the atmosphere that cannot be measured from ground-based radar, weather stations, or weather balloons and have the potential to fill gaps in atmospheric sampling. However, research on the vertical sampling scales for collecting atmospheric measurements from sUAS and the variabilities of these scales across atmospheric phenomena (e.g., temperature and humidity is needed. The objective of this study is to use variogram analysis, a common geostatistical technique, to determine optimal spatial sampling scales for two atmospheric variables (temperature and relative humidity captured from sUAS. Results show that vertical sampling scales of approximately 3 m for temperature and 1.5–2 m for relative humidity were sufficient to capture the spatial structure of these phenomena under the conditions tested. Future work is needed to model these scales across the entire ABL as well as under variable conditions.

  9. 7 CFR 201.42 - Small containers.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Small containers. 201.42 Section 201.42 Agriculture... REGULATIONS Sampling in the Administration of the Act § 201.42 Small containers. In sampling seed in small containers that it is not practical to sample as required in § 201.41, a portion of one unopened container or...

  10. The small displacement elastic solution to the ball-on-ring testing method

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund

    2012-01-01

    The ball-on-ring experiment is used for testing of the biaxial strength of ceramics. In this work the solution for the stress distribution and displacements of the disc specimen in the ball-on-ring experiment are determined on closed form. The solution comprises the displacement field and its...

  11. Photo-stability study of a solution-processed small molecule solar cell system: correlation between molecular conformation and degradation.

    Science.gov (United States)

    Newman, Michael J; Speller, Emily M; Barbé, Jérémy; Luke, Joel; Li, Meng; Li, Zhe; Wang, Zhao-Kui; Jain, Sagar M; Kim, Ji-Seon; Lee, Harrison Ka Hin; Tsoi, Wing Chung

    2018-01-01

    Solution-processed organic small molecule solar cells (SMSCs) have achieved efficiency over 11%. However, very few studies have focused on their stability under illumination and the origin of the degradation during the so-called burn-in period. Here, we studied the burn-in period of a solution-processed SMSC using benzodithiophene terthiophene rhodamine:[6,6]-phenyl C 71 butyric acid methyl ester (BTR:PC 71 BM) with increasing solvent vapour annealing time applied to the active layer, controlling the crystallisation of the BTR phase. We find that the burn-in behaviour is strongly correlated to the crystallinity of BTR. To look at the possible degradation mechanisms, we studied the fresh and photo-aged blend films with grazing incidence X-ray diffraction, UV-vis absorbance, Raman spectroscopy and photoluminescence (PL) spectroscopy. Although the crystallinity of BTR affects the performance drop during the burn-in period, the degradation is found not to originate from the crystallinity changes of the BTR phase, but correlates with changes in molecular conformation - rotation of the thiophene side chains, as resolved by Raman spectroscopy which could be correlated to slight photobleaching and changes in PL spectra.

  12. Conformational effect on small angle neutron scattering behavior of interacting polyelectrolyte solutions: a perspective of integral equation theory.

    Science.gov (United States)

    Shew, Chwen-Yang; Do, Changwoo; Hong, Kunlun; Liu, Yun; Porcar, Lionel; Smith, Gregory S; Chen, Wei-Ren

    2012-07-14

    We present small angle neutron scattering (SANS) measurements of deuterium oxide (D(2)O) solutions of linear and star sodium poly(styrene sulfonate) (NaPSS) as a function of polyelectrolyte concentration. Emphasis is on understanding the dependence of their SANS coherent scattering cross section I(Q) on the molecular architecture of single polyelectrolyte. The key finding is that for a given concentration, star polyelectrolytes exhibit more pronounced characteristic peaks in I(Q), and the position of the first peak occurs at a smaller Q compared to their linear counterparts. Based on a model of integral equation theory, we first compare the SANS experimental I(Q) of salt-free polyelectrolyte solutions with that predicted theoretically. Having seen their satisfactory qualitative agreement, the dependence of counterion association behavior on polyelectrolyte geometry and concentration is further explored. Our predictions reveal that the ionic environment of polyelectrolyte exhibits a strong dependence on polyelectrolyte geometry at lower polyelectrolyte concentration. However, when both linear and star polyelectrolytes exceed their overlap concentrations, the spatial distribution of counterion is found to be essentially insensitive to polyelectrolyte geometry due to the steric effect.

  13. Efficient solution-processed small molecule: Cadmium selenide quantum dot bulk heterojunction solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Vinay, E-mail: drvinaygupta@netscape.net [Physics of Energy Harvesting Division, Organic and Hybrid Solar Cell Group, CSIR-National Physical Laboratory, New Delhi-110012 (India); Department of Physics, University of California, Santa Barbara, California 93106 (United States); Upreti, Tanvi; Chand, Suresh [Physics of Energy Harvesting Division, Organic and Hybrid Solar Cell Group, CSIR-National Physical Laboratory, New Delhi-110012 (India)

    2013-12-16

    We report bulk heterojunction solar cells based on blends of solution-processed small molecule [7,7′-(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b′]dithiophene-2,6-diyl) bis(6-fluoro-4-(5′-hexyl-[2,2′-bithiophen]-5yl)benzo[c] [1,2,5] thiadiazole)] p-DTS(FBTTh{sub 2}){sub 2}: Cadmium Selenide (CdSe) (70:30, 60:40, 50:50, and 40:60) in the device configuration: Indium Tin Oxide /poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/p-DTS(FBTTh{sub 2}){sub 2}: CdSe/Ca/Al. The optimized ratio of p-DTS(FBTTh{sub 2}){sub 2}:CdSe::60:40 leads to a short circuit current density (J{sub sc}) = 5.45 mA/cm{sup 2}, open circuit voltage (V{sub oc}) = 0.727 V, and fill factor (FF) = 51%, and a power conversion efficiency = 2.02% at 100 mW/cm{sup 2} under AM1.5G illumination. The J{sub sc} and FF are sensitive to the ratio of p-DTS(FBTTh{sub 2}){sub 2}:CdSe, which is a crucial factor for the device performance.

  14. A Simple Method for Automated Solid Phase Extraction of Water Samples for Immunological Analysis of Small Pollutants.

    Science.gov (United States)

    Heub, Sarah; Tscharner, Noe; Kehl, Florian; Dittrich, Petra S; Follonier, Stéphane; Barbe, Laurent

    2016-01-01

    A new method for solid phase extraction (SPE) of environmental water samples is proposed. The developed prototype is cost-efficient and user friendly, and enables to perform rapid, automated and simple SPE. The pre-concentrated solution is compatible with analysis by immunoassay, with a low organic solvent content. A method is described for the extraction and pre-concentration of natural hormone 17β-estradiol in 100 ml water samples. Reverse phase SPE is performed with octadecyl-silica sorbent and elution is done with 200 µl of methanol 50% v/v. Eluent is diluted by adding di-water to lower the amount of methanol. After preparing manually the SPE column, the overall procedure is performed automatically within 1 hr. At the end of the process, estradiol concentration is measured by using a commercial enzyme-linked immune-sorbent assay (ELISA). 100-fold pre-concentration is achieved and the methanol content in only 10% v/v. Full recoveries of the molecule are achieved with 1 ng/L spiked de-ionized and synthetic sea water samples.

  15. Safety evaluation of small samples for isotope production

    International Nuclear Information System (INIS)

    Sharma, Archana; Singh, Tej; Varde, P.V.

    2015-09-01

    Radioactive isotopes are widely used in basic and applied science and engineering, most notably as environmental and industrial tracers, and for medical imaging procedures. Production of radioisotope constitutes important activity of Indian nuclear program. Since its initial criticality DHRUVA reactor has been facilitating the regular supply of most of the radioisotopes required in the country for application in the fields of medicine, industry and agriculture. In-pile irradiation of the samples requires a prior estimation of the sample reactivity load, heating rate, activity developed and shielding thickness required for post irradiation handling. This report is an attempt to highlight the contributions of DHRUVA reactor, as well as to explain in detail the methodologies used in safety evaluation of the in pile irradiation samples. (author)

  16. The Modification of Sodium Polyacrylate Water Solution Cooling Properties by AL2O3

    Directory of Open Access Journals (Sweden)

    Wojciech Gęstwa

    2010-01-01

    Based on cooling curves, it can be concluded that for the water solution of sodium polyacrylate with AL2O3 nanoparticles in comparison to water and 10% polymer water solution lower cooling speed is obtained. The cooling medium containing nanoparticles provides lower cooling speed in the smallest surface austenite occurance (500–600 C in the charts of the CTP for most nonalloy structural steels and low-alloy steels. However lower cooling temperature at the beginning of martensitic transformation causes the formation of smaller internal stresses, leading to smaller dimensional changes and hardening deformation. For the quenching media the wetting angle was appointed by the drop-shape method. These studies showed the best wettability of polymer water solution (sodium polyacrylate with the addition of AL2O3 nanoparticles, whose wetting angle was about 65 degrees. Obtaining the smallest wetting angle for the medium containing nanoparticles suggests that the heat transfer to the cooling medium is larger. This allows slower cooling at the same time ensuring its homogeneity. The obtained values of wetting angle confirm the conclusions drawn on the basis of cooling curves and allowus to conclude that in the case of the heat transfer rate it will have a lower value than for water and 10% polymer water solution. In the research on hardened carburized steel samples C10 and 16MnCr5 surface hardness, impact strength and changes in the size of cracks in Navy C-ring sample are examined. On this basis of the obtained results it can be concluded that polymer water solution with nanoparticles allows to obtain a better impact strength at comparable hardness on the surface. Research on the dimensional changes on the basis of the sample of Navy C-ring also shows small dimensional changes for samples carburized and hardened in 10% polymer water solution with the addition of nanoparticles AL2O3. Smaller dimensional changes were obtained for samples of steel 16MnCr5 thanfar C10. The

  17. Algorithm for computing significance levels using the Kolmogorov-Smirnov statistic and valid for both large and small samples

    Energy Technology Data Exchange (ETDEWEB)

    Kurtz, S.E.; Fields, D.E.

    1983-10-01

    The KSTEST code presented here is designed to perform the Kolmogorov-Smirnov one-sample test. The code may be used as a stand-alone program or the principal subroutines may be excerpted and used to service other programs. The Kolmogorov-Smirnov one-sample test is a nonparametric goodness-of-fit test. A number of codes to perform this test are in existence, but they suffer from the inability to provide meaningful results in the case of small sample sizes (number of values less than or equal to 80). The KSTEST code overcomes this inadequacy by using two distinct algorithms. If the sample size is greater than 80, an asymptotic series developed by Smirnov is evaluated. If the sample size is 80 or less, a table of values generated by Birnbaum is referenced. Valid results can be obtained from KSTEST when the sample contains from 3 to 300 data points. The program was developed on a Digital Equipment Corporation PDP-10 computer using the FORTRAN-10 language. The code size is approximately 450 card images and the typical CPU execution time is 0.19 s.

  18. Business Intelligence and Implementation in a Small Enterprise

    Directory of Open Access Journals (Sweden)

    Marketa Horakova

    2013-04-01

    Full Text Available Business Intelligence (BI systems provide users for information and analysis to better support with tactical and strategic business decision processes. This article summarizes the current trends in BI systems, discusses aspects of BI tools and BI solutions in small and medium businesses. Principles of integration of multidimensional views of business data with analytical and visualization tools are studied and described here. An example of a BI solution implementation in a small company shows how the multidimensional analytical data model and related applications can be designed, created and implemented for the small company.

  19. Improvement of Physico-mechanical Properties of Partially Amorphous Acetaminophen Developed from Hydroalcoholic Solution Using Spray Drying Technique

    Science.gov (United States)

    Sadeghi, Fatemeh; Torab, Mansour; Khattab, Mostafa; Homayouni, Alireza; Afrasiabi Garekani, Hadi

    2013-01-01

    Objective(s): This study was performed aiming to investigate the effect of particle engineering via spray drying of hydroalcoholic solution on solid states and physico-mechanical properties of acetaminophen. Materials and Methods: Spray drying of hydroalcoholic solution (25% v/v ethanol/water) of acetaminophen (5% w/v) in the presence of small amounts of polyninylpyrrolidone K30 (PVP) (0, 1.25, 2.5 and 5% w/w based on acetaminophen weight) was carried out. The properties of spray dried particles namely morphology, surface characteristics, particle size, crystallinity, dissolution rate and compactibility were evaluated. Results: Spray drying process significantly changed the morphology of acetaminophen crystals from acicular (rod shape) to spherical microparticle. Differential scanning calorimetery (DSC) and x-ray powder diffraction (XRPD) studies ruled out any polymorphism in spray dried samples, however, a major reduction in crystallinity up to 65%, especially for those containing 5% w/w PVP was observed. Spray dried acetaminophen particles especially those obtained in the presence of PVP exhibited an obvious improvement of the dissolution and compaction properties. Tablets produced from spray dried samples exhibited excellent crushing strengths and no tendency to cap. Conclusions: The findings of this study revealed that spray drying of acetaminophen from hydroalcoholic solution in the presence of small amount of PVP produced partially amorphous particles with improved dissolution and excellent compaction properties. PMID:24379968

  20. Electrochemical studies on stress corrosion cracking of incoloy-800 in caustic solution. Part II: Precracking samples

    Directory of Open Access Journals (Sweden)

    Dinu Alice

    2006-01-01

    Full Text Available Stress corrosion cracking (SCC in a caustic medium may affect the secondary circuit tubing of a CANDU NPP cooled with river water, due to an accidental formation of a concentrated alkaline environment in the areas with restricted circulation, as a result of a leakage of cooling water from the condenser. To evaluate the susceptibility of Incoloy-800 (used to manufacture steam generator tubes for CANDU NPP to SCC, some accelerated corrosion tests were conducted in an alkaline solution (10% NaOH, pH = 13. These experiments were performed at ambient temperature and 85 °C. We used the potentiodynamic method and the potentiostatic method, simultaneously monitoring the variation of the open circuit potential during a time period (E corr/time curve. The C-ring method was used to stress the samples. In order to create stress concentrations, mechanical precracks with a depth of 100 or 250 μm were made on the outer side of the C-rings. Experimental results showed that the stressed samples were more susceptible to SCC than the unstressed samples whereas the increase in temperature and crack depth lead to an increase in SCC susceptibility. Incipient micro cracks of a depth of 30 μm were detected in the area of the highest peak of the mechanical precrack.

  1. Determination of 129I/127I isotope ratios in liquid solutions and environmental soil samples by ICP-MS with hexapole collision cell

    OpenAIRE

    Izmer, A. V.; Boulyga, S. F.; Becker, J. S.

    2003-01-01

    The determination of I-129 in environmental samples at ultratrace levels is very difficult by ICP-MS due to a high noise caused by Xe impurities in argon plasma gas (interference of Xe-129(+)), possible (IH2+)-I-127 interference and an insufficient abundance ratio sensitivity of the ICP mass spectrometer for I-129/I-127 isotope ratio measurement. A sensitive, powerful and fast analytical technique for iodine isotope ratio measurements in aqueous solutions and contaminated soil samples directl...

  2. A rheo-optical apparatus for real time kinetic studies on shear-induced alignment of self-assembled soft matter with small sample volumes

    Science.gov (United States)

    Laiho, Ari; Ikkala, Olli

    2007-01-01

    In soft materials, self-assembled nanoscale structures can allow new functionalities but a general problem is to align such local structures aiming at monodomain overall order. In order to achieve shear alignment in a controlled manner, a novel type of rheo-optical apparatus has here been developed that allows small sample volumes and in situ monitoring of the alignment process during the shear. Both the amplitude and orientation angles of low level linear birefringence and dichroism are measured while the sample is subjected to large amplitude oscillatory shear flow. The apparatus is based on a commercial rheometer where we have constructed a flow cell that consists of two quartz teeth. The lower tooth can be set in oscillatory motion whereas the upper one is connected to the force transducers of the rheometer. A custom made cylindrical oven allows the operation of the flow cell at elevated temperatures up to 200 °C. Only a small sample volume is needed (from 9 to 25 mm3), which makes the apparatus suitable especially for studying new materials which are usually obtainable only in small quantities. Using this apparatus the flow alignment kinetics of a lamellar polystyrene-b-polyisoprene diblock copolymer is studied during shear under two different conditions which lead to parallel and perpendicular alignment of the lamellae. The open device geometry allows even combined optical/x-ray in situ characterization of the alignment process by combining small-angle x-ray scattering using concepts shown by Polushkin et al. [Macromolecules 36, 1421 (2003)].

  3. The Effect of Small Sample Size on Measurement Equivalence of Psychometric Questionnaires in MIMIC Model: A Simulation Study

    Directory of Open Access Journals (Sweden)

    Jamshid Jamali

    2017-01-01

    Full Text Available Evaluating measurement equivalence (also known as differential item functioning (DIF is an important part of the process of validating psychometric questionnaires. This study aimed at evaluating the multiple indicators multiple causes (MIMIC model for DIF detection when latent construct distribution is nonnormal and the focal group sample size is small. In this simulation-based study, Type I error rates and power of MIMIC model for detecting uniform-DIF were investigated under different combinations of reference to focal group sample size ratio, magnitude of the uniform-DIF effect, scale length, the number of response categories, and latent trait distribution. Moderate and high skewness in the latent trait distribution led to a decrease of 0.33% and 0.47% power of MIMIC model for detecting uniform-DIF, respectively. The findings indicated that, by increasing the scale length, the number of response categories and magnitude DIF improved the power of MIMIC model, by 3.47%, 4.83%, and 20.35%, respectively; it also decreased Type I error of MIMIC approach by 2.81%, 5.66%, and 0.04%, respectively. This study revealed that power of MIMIC model was at an acceptable level when latent trait distributions were skewed. However, empirical Type I error rate was slightly greater than nominal significance level. Consequently, the MIMIC was recommended for detection of uniform-DIF when latent construct distribution is nonnormal and the focal group sample size is small.

  4. The Effect of Small Sample Size on Measurement Equivalence of Psychometric Questionnaires in MIMIC Model: A Simulation Study.

    Science.gov (United States)

    Jamali, Jamshid; Ayatollahi, Seyyed Mohammad Taghi; Jafari, Peyman

    2017-01-01

    Evaluating measurement equivalence (also known as differential item functioning (DIF)) is an important part of the process of validating psychometric questionnaires. This study aimed at evaluating the multiple indicators multiple causes (MIMIC) model for DIF detection when latent construct distribution is nonnormal and the focal group sample size is small. In this simulation-based study, Type I error rates and power of MIMIC model for detecting uniform-DIF were investigated under different combinations of reference to focal group sample size ratio, magnitude of the uniform-DIF effect, scale length, the number of response categories, and latent trait distribution. Moderate and high skewness in the latent trait distribution led to a decrease of 0.33% and 0.47% power of MIMIC model for detecting uniform-DIF, respectively. The findings indicated that, by increasing the scale length, the number of response categories and magnitude DIF improved the power of MIMIC model, by 3.47%, 4.83%, and 20.35%, respectively; it also decreased Type I error of MIMIC approach by 2.81%, 5.66%, and 0.04%, respectively. This study revealed that power of MIMIC model was at an acceptable level when latent trait distributions were skewed. However, empirical Type I error rate was slightly greater than nominal significance level. Consequently, the MIMIC was recommended for detection of uniform-DIF when latent construct distribution is nonnormal and the focal group sample size is small.

  5. On the microstructure of organic solutions of mono-carboxylic acids: Combined study by infrared spectroscopy, small-angle neutron scattering and molecular dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Eremin, Roman A., E-mail: era@jinr.ru [Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Kholmurodov, Kholmirzo T. [Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); International University “Dubna”, Dubna 141980 (Russian Federation); Petrenko, Viktor I. [Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Taras Shevchenko National University of Kyiv, Kyiv 03022 (Ukraine); Rosta, László [Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest H-1525 (Hungary); Grigoryeva, Natalia A. [Faculty of Physics, Saint-Petersburg State University, 198504 Saint-Petersburg (Russian Federation); Avdeev, Mikhail V. [Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation)

    2015-11-05

    Highlights: • The model of the scattering particle for a reliable SANS analysis is proposed. • The structural parameters of saturated mono-carboxylic acids in solutions are obtained. • The differences in nematic transitions correlate to solvation peculiarities. - Abstract: The data of infrared spectroscopy (IR), molecular dynamics (MD) simulations and small-angle neutron scattering (SANS) have been combined to conclude about the nanoscale structural organization of organic non-polar solutions of saturated mono-carboxylic acids with different alkyl chain lengths for diluted solutions of saturated myristic (C14) and stearic (C18) acids in benzene and decalin. In particular, the degree of dimerization was found from the IR spectra. The structural anisotropy of the acids and their dimers was used in the treatment of the data of MD simulations to describe the solute–solvent interface in a cylindrical approximation and show its rather strong influence on SANS. The corresponding scattering length density profiles were used to fit the experimental SANS data comprising the information about the acid molecule isomerization. The SANS data from concentrated solutions showed a partial self-assembling of the acids within the nematic transition is different for two solvents due to lyophobic peculiarities.

  6. 197 Au Mössbauer study of the gold species adsorbed on carbon from cyanide solutions

    Science.gov (United States)

    Kongolo, K.; Bahr, A.; Friedl, J.; Wagner, F. E.

    1990-04-01

    The gold species present on activated carbon after adsorption from solutions of Au(CN)2 - have been studied by197Au Mössbauer spectroscopy as a function of the pH value of the solution, the loading of the carbon, the coadsorption of polyvalent cations, and the treatment of the samples after adsorption. The gold was found to be adsorbed mainly as Au(CN)2 -. Coadsorbed polyvalent cations (Ca²+, Gd³+) have no influence on the Mössbauer parameters of the adsorbed gold complex. After adsorption from acidic solutions (pH ≲ 4), one finds a substantial amount of adsorbed gold with Mössbauer parameters similar to those of crystalline AuCN. Presumably, this gold is bound in Aux(CN)x+1 oligomers which form during drying. An additional product with Mössbauer parameters close to those of KAu(CN)2Cl2 was observed on dried samples after adsorption at pH 1. A minor gold species with an uncommonly small electric quadrupole splitting was found on wet carbons but disappeared on drying.

  7. Small population size of Pribilof Rock Sandpipers confirmed through distance-sampling surveys in Alaska

    Science.gov (United States)

    Ruthrauff, Daniel R.; Tibbitts, T. Lee; Gill, Robert E.; Dementyev, Maksim N.; Handel, Colleen M.

    2012-01-01

    The Rock Sandpiper (Calidris ptilocnemis) is endemic to the Bering Sea region and unique among shorebirds in the North Pacific for wintering at high latitudes. The nominate subspecies, the Pribilof Rock Sandpiper (C. p. ptilocnemis), breeds on four isolated islands in the Bering Sea and appears to spend the winter primarily in Cook Inlet, Alaska. We used a stratified systematic sampling design and line-transect method to survey the entire breeding range of this population during springs 2001-2003. Densities were up to four times higher on the uninhabited and more northerly St. Matthew and Hall islands than on St. Paul and St. George islands, which both have small human settlements and introduced reindeer herds. Differences in density, however, appeared to be more related to differences in vegetation than to anthropogenic factors, raising some concern for prospective effects of climate change. We estimated the total population at 19 832 birds (95% CI 17 853–21 930), ranking it among the smallest of North American shorebird populations. To determine the vulnerability of C. p. ptilocnemis to anthropogenic and stochastic environmental threats, future studies should focus on determining the amount of gene flow among island subpopulations, the full extent of the subspecies' winter range, and the current trajectory of this small population.

  8. Evolution of pH during in-situ leaching in small concrete cavities

    Energy Technology Data Exchange (ETDEWEB)

    Saguees, A.A. [Univ. of South Florida, Tampa, FL (United States). Dept. of Civil and Environmental Engineering; Moreno, E.I. [Univ. of South Florida, Tampa, FL (United States). Dept. of Civil and Environmental Engineering]|[CINVESTAV Merida-Unit (Mexico); Andrade, C. [CSIC, Madrid (Spain). Inst. Eduardo Torroja de Ciencias de la Construccion

    1997-11-01

    Small amounts (0.4 cc) of neutral water placed in small cylindrical cavities (5 mm diameter) in concrete exposed to 100% relative humidity first developed a pH comparable to that of a saturated Ca(OH){sub 2} solution. The pH then increased over a period of days-weeks toward a higher terminal value. A micro pH electrode arrangement was used. This behavior was observed in samples of 12 different concrete mix designs, including some with pozzolanic additions. The average terminal cavity pH closely approached that of expressed pore water from the same concretes. A simplified mathematical model reproduced the experimentally observed behavior. The model assumed inward diffusional transport of the pH-determining species in the surrounding concrete pore solution. The experimental results were consistent with the model predictions when using diffusion parameters on the order of those previously reported for alkali cations in concrete. The cavity size, cavity water content, and exposure to atmospheric CO{sub 2} should be minimized when attempting to obtain cavity pH values approaching those of the surrounding pore water.

  9. Solution of Full Wave Equation for Global Modes in Small Aspect Ratio Tokamaks with Non-Circular Cross-Section

    International Nuclear Information System (INIS)

    Burma, C.; Cuperman, S.; Komoshvili, K.

    1998-01-01

    The wave equation for strongly toroidal small aspect ratio (spherical) tokamaks with non-circular cross-section is properly formulated and solved for global waves, in the Alfven frequency range. The current-carrying toroidal plasma is surrounded by a helical sheet-current antenna, which is enclosed within a perfectly conducting wall. The problem is formulated in terms of the vector and scalar potentials (A,Φ), thus avoiding the numerical solution occurring in the case of (E,B) formulation. Adequate boundary conditions are applied at the vacuum - metallic wall interface and the magnetic axis. A recently derived dielectric tensor-operator, able to describe the anisotropic plasma response in spherical tokamaks, is used for this purpose; except for its linear character, no physical or geometrical limitations are imposed on it. The equilibrium profiles (magnetic field, pressure and current) are obtained from a numerical solution of the Grad-Shafranov equation. Specifically, the wave equation is solved by the aid of a numerical code we developed for the present problem, based on the well documented 2(1/2)D finite element solver proposed by E.G. Sewell. With the definitions V i (θ,ρ) = U i (-θ,ρ) (V i U i = A j , Φ; j = ρ,φ,θ), our code solves simultaneously 16 second order partial differential equations (eight equations for each of real and imaginary set of functions V i , U i ). A systematic analysis of the solutions obtained for various values and combinations of wavenumbers and frequencies in the Alfven range is presented

  10. Why are small software organisations different?

    OpenAIRE

    Richardson, Ita; Gresse von Wangenheim, Christiane

    2007-01-01

    peer-reviewed Small software organizations independently financed and organized companies with fewer than 50 employees are fundamental to many national economies' growth. In the US, Brazil, Canada, China, India, Finland, Ireland, Hungary, and many other countries, small companies represent up to 85 percent of all software organizations. However, to persist and grow, small software companies need efficient, effective software engineering solutions.

  11. A study on the structure of thorium salt solutions

    International Nuclear Information System (INIS)

    Magini, M.; Cabrini, A.; Di Bartolomeo, A.

    1975-01-01

    The structure of highly hydrolyzed thorium salt solutions has been investigated by large and small angle X-ray scattering techniques. The diffraction data obtained with large angle measurements show the presence in solution of microcrystalline particles with the thorium oxide structure. Particles larger than those were discovered by small angle measurements. A possible shape of these colloidal particles has been discussed

  12. Ions, solutes and solvents, oh my!

    Energy Technology Data Exchange (ETDEWEB)

    Kemp, Daniel David [Iowa State Univ., Ames, IA (United States)

    2009-08-01

    Modern methods in ab initio quantum mechanics have become efficient and accurate enough to study many gas-phase systems. However, chemists often work in the solution phase. The presence of solvent molecules has been shown to affect reaction mechanisms1, lower reaction energy barriers2, participate in energy transfer with the solute3 and change the physical properties of the solute4. These effects would be overlooked in simple gas phase calculations. Careful study of specific solvents and solutes must be done in order to fully understand the chemistry of the solution phase. Water is a key solvent in chemical and biological applications. The properties of an individual water molecule (a monomer) and the behavior of thousands of molecules (bulk solution) are well known for many solvents. Much is also understood about aqueous microsolvation (small clusters containing ten water molecules or fewer) and the solvation characteristics when bulk water is chosen to solvate a solute. However, much less is known about how these properties behave as the cluster size transitions from the microsolvated cluster size to the bulk. This thesis will focus on species solvated with water clusters that are large enough to exhibit the properties of the bulk but small enough to consist of fewer than one hundred solvent molecules. New methods to study such systems will also be presented.

  13. Uremic Solutes in Chronic Kidney Disease and Their Role in Progression.

    Directory of Open Access Journals (Sweden)

    Jan A J G van den Brand

    Full Text Available To date, over 150 possible uremic solutes have been listed, but their role in the progression of CKD is largely unknown. Here, the association between a selected panel of uremic solutes and progression in CKD patients was investigated.Patients from the MASTERPLAN study, a randomized controlled trial in CKD patients with a creatinine clearance between 20 and 70 ml/min per 1.73m2, were selected based on their rate of eGFR decline during the first five years of follow-up. They were categorized as rapid (decline >5 ml/min per year or slow progressors. Concentrations of eleven uremic solutes were obtained at baseline and after one year of follow-up. Logistic regression was used to compare the odds for rapid to slow progression by uremic solute concentrations at baseline. Variability in uremic solute levels was assessed using scatter plots, and limits of variability were calculated.In total, 40 rapidly and 40 slowly progressing patients were included. Uremic solutes were elevated in all patients compared to reference values for healthy persons. The serum levels of uremic solutes were not associated with rapid progression. Moreover, we observed substantial variability in solute levels over time.Elevated concentrations of uremic solutes measured in this study did not explain differences in rate of eGFR decline in CKD patients, possibly due to lack of power as a result of the small sample size, substantial between patient variability, and variability in solute concentrations over time. The etiology of intra-individual variation in uremic solute levels remains to be elucidated.

  14. Uremic Solutes in Chronic Kidney Disease and Their Role in Progression.

    Science.gov (United States)

    van den Brand, Jan A J G; Mutsaers, Henricus A M; van Zuilen, Arjan D; Blankestijn, Peter J; van den Broek, Petra H; Russel, Frans G M; Masereeuw, Rosalinde; Wetzels, Jack F M

    2016-01-01

    To date, over 150 possible uremic solutes have been listed, but their role in the progression of CKD is largely unknown. Here, the association between a selected panel of uremic solutes and progression in CKD patients was investigated. Patients from the MASTERPLAN study, a randomized controlled trial in CKD patients with a creatinine clearance between 20 and 70 ml/min per 1.73m2, were selected based on their rate of eGFR decline during the first five years of follow-up. They were categorized as rapid (decline >5 ml/min per year) or slow progressors. Concentrations of eleven uremic solutes were obtained at baseline and after one year of follow-up. Logistic regression was used to compare the odds for rapid to slow progression by uremic solute concentrations at baseline. Variability in uremic solute levels was assessed using scatter plots, and limits of variability were calculated. In total, 40 rapidly and 40 slowly progressing patients were included. Uremic solutes were elevated in all patients compared to reference values for healthy persons. The serum levels of uremic solutes were not associated with rapid progression. Moreover, we observed substantial variability in solute levels over time. Elevated concentrations of uremic solutes measured in this study did not explain differences in rate of eGFR decline in CKD patients, possibly due to lack of power as a result of the small sample size, substantial between patient variability, and variability in solute concentrations over time. The etiology of intra-individual variation in uremic solute levels remains to be elucidated.

  15. Automated acquisition and analysis of small angle X-ray scattering data

    International Nuclear Information System (INIS)

    Franke, Daniel; Kikhney, Alexey G.; Svergun, Dmitri I.

    2012-01-01

    Small Angle X-ray Scattering (SAXS) is a powerful tool in the study of biological macromolecules providing information about the shape, conformation, assembly and folding states in solution. Recent advances in robotic fluid handling make it possible to perform automated high throughput experiments including fast screening of solution conditions, measurement of structural responses to ligand binding, changes in temperature or chemical modifications. Here, an approach to full automation of SAXS data acquisition and data analysis is presented, which advances automated experiments to the level of a routine tool suitable for large scale structural studies. The approach links automated sample loading, primary data reduction and further processing, facilitating queuing of multiple samples for subsequent measurement and analysis and providing means of remote experiment control. The system was implemented and comprehensively tested in user operation at the BioSAXS beamlines X33 and P12 of EMBL at the DORIS and PETRA storage rings of DESY, Hamburg, respectively, but is also easily applicable to other SAXS stations due to its modular design.

  16. Analytical solution of strongly nonlinear Duffing oscillators

    OpenAIRE

    El-Naggar, A.M.; Ismail, G.M.

    2016-01-01

    In this paper, a new perturbation technique is employed to solve strongly nonlinear Duffing oscillators, in which a new parameter α=α(ε)α=α(ε) is defined such that the value of α is always small regardless of the magnitude of the original parameter εε. Therefore, the strongly nonlinear Duffing oscillators with large parameter ε are transformed into a small parameter system with respect to αα. Approximate solution obtained by the present method is compared with the solution of energy balance m...

  17. Sample Results From Tank 48H Samples HTF-48-14-158, -159, -169, and -170

    Energy Technology Data Exchange (ETDEWEB)

    Peters, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hang, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-04-28

    Savannah River National Laboratory (SRNL) analyzed samples from Tank 48H in support of determining the cause for the unusually high dose rates at the sampling points for this tank. A set of two samples was taken from the quiescent tank, and two additional samples were taken after the contents of the tank were mixed. The results of the analyses of all the samples show that the contents of the tank have changed very little since the analysis of the previous sample in 2012. The solids are almost exclusively composed of tetraphenylborate (TPB) salts, and there is no indication of acceleration in the TPB decomposition. The filtrate composition shows a moderate increase in salt concentration and density, which is attributable to the addition of NaOH for the purposes of corrosion control. An older modeling simulation of the TPB degradation was updated, and the supernate results from a 2012 sample were run in the model. This result was compared to the results from the 2014 recent sample results reported in this document. The model indicates there is no change in the TPB degradation from 2012 to 2014. SRNL measured the buoyancy of the TPB solids in Tank 48H simulant solutions. It was determined that a solution of density 1.279 g/mL (~6.5M sodium) was capable of indefinitely suspending the TPB solids evenly throughout the solution. A solution of density 1.296 g/mL (~7M sodium) caused a significant fraction of the solids to float on the solution surface. As the experiments could not include the effect of additional buoyancy elements such as benzene or hydrogen generation, the buoyancy measurements provide an upper bound estimate of the density in Tank 48H required to float the solids.

  18. A new perspective on the nonextremal Enhancon solution

    International Nuclear Information System (INIS)

    Barrett, Jessica K.

    2006-01-01

    We discuss the nonextremal generalisation of the enhancon mechanism. We find that the nonextremal shell branch solution does not violate the Weak Energy Condition when the nonextremality parameter is small, in contrast to earlier discussions of this subject. We show that this physical shell branch solution fills the mass gap between the extremal enhancon solution and the nonextremal horizon branch solution

  19. Antibiotic Resistance in Animal and Environmental Samples Associated with Small-Scale Poultry Farming in Northwestern Ecuador.

    Science.gov (United States)

    Braykov, Nikolay P; Eisenberg, Joseph N S; Grossman, Marissa; Zhang, Lixin; Vasco, Karla; Cevallos, William; Muñoz, Diana; Acevedo, Andrés; Moser, Kara A; Marrs, Carl F; Foxman, Betsy; Trostle, James; Trueba, Gabriel; Levy, Karen

    2016-01-01

    The effects of animal agriculture on the spread of antibiotic resistance (AR) are cross-cutting and thus require a multidisciplinary perspective. Here we use ecological, epidemiological, and ethnographic methods to examine populations of Escherichia coli circulating in the production poultry farming environment versus the domestic environment in rural Ecuador, where small-scale poultry production employing nontherapeutic antibiotics is increasingly common. We sampled 262 "production birds" (commercially raised broiler chickens and laying hens) and 455 "household birds" (raised for domestic use) and household and coop environmental samples from 17 villages between 2010 and 2013. We analyzed data on zones of inhibition from Kirby-Bauer tests, rather than established clinical breakpoints for AR, to distinguish between populations of organisms. We saw significantly higher levels of AR in bacteria from production versus household birds; resistance to either amoxicillin-clavulanate, cephalothin, cefotaxime, and gentamicin was found in 52.8% of production bird isolates and 16% of household ones. A strain jointly resistant to the 4 drugs was exclusive to a subset of isolates from production birds (7.6%) and coop surfaces (6.5%) and was associated with a particular purchase site. The prevalence of AR in production birds declined with bird age (P resistance (AR) in E. coli isolates from small-scale poultry production environments versus domestic environments in rural Ecuador, where such backyard poultry operations have become established over the past decade. Our previous research in the region suggests that introduction of AR bacteria through travel and commerce may be an important source of AR in villages of this region. This report extends the prior analysis by examining small-scale production chicken farming as a potential source of resistant strains. Our results suggest that AR strains associated with poultry production likely originate from sources outside the study

  20. Gas generation from Hanford grout samples

    International Nuclear Information System (INIS)

    Jonah, C.D.; Kapoor, S.; Matheson, M.S.; Mulac, W.A.; Meisel, D.

    1996-01-01

    In an extension of our work on the radiolytic processes that occur in the waste tanks at the Hanford site, we studied the gas generation from grout samples that contained nuclear waste simulants. Grout is one option for the long-term storage of low-level nuclear waste solutions but the radiolytic effects on grout have not been thoroughly defined. In particular, the generation of potentially flammable and hazardous gases required quantification. A research team at Argonne examined this issue and found that the total amount of gases generated radiolytically from the WHC samples was an order of magnitude higher than predicted. This implies that novel pathways fro charge migration from the solid grout to the associated water are responsible for gas evolution. The grout samples produced hydrogen, nitrous oxide, and carbon monoxide as well as nitrogen and oxygen. Yields of each of these substances were determined for doses that are equivalent to about 80 years storage of the grout. Carbon monoxide, which was produced in 2% yield, is of particular importance because even small amounts may adversely affect catalytic conversion instrumentation that has been planned for installation in the storage vaults

  1. Small polaron hopping conduction in samples of ceramic La1.4Sr1.6Mn2O7.06

    International Nuclear Information System (INIS)

    Nakatsugawa, H.; Iguchi, E.; Jung, W.H.; Munakata, F.

    1999-01-01

    The ceramic sample of La 1.4 Sr 1.6 Mn 2 O 7.06 exhibits the metal-insulator transition and a negative magnetoresistance in the vicinity of the Curie temperature (T C ∼ 100 K). The dc magnetic susceptibility between 100 K and 280 K is nearly constant and decreases gradually with increasing temperature above 280 K. The measurements of dc resistivity and the thermoelectric power indicate that small polaron hopping conduction takes place at T > 280 K. The spin ordering due to the two-dimensional d x 2 -y 2 state occurring at T > 280 K is directly related to the hopping conduction above 280 K, although the spin ordering due to the one-dimensional d 3z 2 -r 2 state takes place at T > T C . The two-dimensional d x 2 -y 2 state extending within the MnO 2 sheets starts to narrow and leads to the carrier localisation at 280 K. The effective number of holes in this sample estimated from the thermoelectric power is considerably smaller than the nominal value. This indicates that the small polaron hopping conduction takes place predominantly within the in-plane MnO 2 sheets. A discussion is given of the experimental results of the ceramic sample of La 2/3 Ca 1/3 MnO 2.98 . Copyright (1999) CSIRO Australia

  2. A new technique to preserve raw materials of ancient monuments against the humidity and its test using 22Na labeled solutions

    International Nuclear Information System (INIS)

    Martinez, G.L.; Navarrete, J.M.

    2007-01-01

    Erosion caused by external factors such as wind, rain, sunlight and temperature changes is considerable in raw materials used to build pre-hispanic monuments. However, there does exist an internal destruction factor even stronger: the humidity coming from the soil, which goes up by capillarity, depositing soluble salts on the walls surface. Therefore, one way to find some figure related to the specific capillarity or porosity shown by each raw material, is to obtain small prism-shaped pieces cut out from the large debris fallen down spontaneously from ancient walls due to internal humidity. Once these small samples are placed in contact with a 22 Na labeled solution during a given time, at the same geometrical conditions, dried overnight, conditioned either in test tubes or wrapped into polyethylene and detected in a well type 3' x 3' scintillation detector, the counts accumulated per time and weight units are a measure of the relative porosity shown by each material. In order to pull down this porosity, the samples are impregnated with a gelatin solution (50 g/l) at 60-80 deg C plus food preservatives such as potassium sorbate (2.5%) and sodium benzoate (2.5%). When gelatin begins to be formed 3 hours later and the samples look humid and brilliant, they are impregnated with formaldehyde solution (38%), and their absorption rate is dramatically reduced overnight (75-100%), which can be proven when samples are tested by making use of the 22 Na labeled solution. This technique has been applied at real scale in some pre-hispanic monuments. Ancient raw materials seems to be much more compact and well preserved during one limited period of time (10 to 13 months). Treatment is unnoticeable and reversible, and it may be applied periodically. (author)

  3. Success and failure rates of tumor genotyping techniques in routine pathological samples with non-small-cell lung cancer.

    Science.gov (United States)

    Vanderlaan, Paul A; Yamaguchi, Norihiro; Folch, Erik; Boucher, David H; Kent, Michael S; Gangadharan, Sidharta P; Majid, Adnan; Goldstein, Michael A; Huberman, Mark S; Kocher, Olivier N; Costa, Daniel B

    2014-04-01

    Identification of some somatic molecular alterations in non-small-cell lung cancer (NSCLC) has become evidence-based practice. The success and failure rate of using commercially available tumor genotyping techniques in routine day-to-day NSCLC pathology samples is not well described. We sought to evaluate the success and failure rate of EGFR mutation, KRAS mutation, and ALK FISH in a cohort of lung cancers subjected to routine clinical tumor genotype. Clinicopathologic data, tumor genotype success and failure rates were retrospectively compiled and analyzed from 381 patient-tumor samples. From these 381 patients with lung cancer, the mean age was 65 years, 61.2% were women, 75.9% were white, 27.8% were never smokers, 73.8% had advanced NSCLC and 86.1% had adenocarcinoma histology. The tumor tissue was obtained from surgical specimens in 48.8%, core needle biopsies in 17.9%, and as cell blocks from aspirates or fluid in 33.3% of cases. Anatomic sites for tissue collection included lung (49.3%), lymph nodes (22.3%), pleura (11.8%), bone (6.0%), brain (6.0%), among others. The overall success rate for EGFR mutation analysis was 94.2%, for KRAS mutation 91.6% and for ALK FISH 91.6%. The highest failure rates were observed when the tissue was obtained from image-guided percutaneous transthoracic core-needle biopsies (31.8%, 27.3%, and 35.3% for EGFR, KRAS, and ALK tests, respectively) and bone specimens (23.1%, 15.4%, and 23.1%, respectively). In specimens obtained from bone, the failure rates were significantly higher for biopsies than resection specimens (40% vs. 0%, p=0.024 for EGFR) and for decalcified compared to non-decalcified samples (60% vs. 5.5%, p=0.021 for EGFR). Tumor genotype techniques are feasible in most samples, outside small image-guided percutaneous transthoracic core-needle biopsies and bone samples from core biopsies with decalcification, and therefore expansion of routine tumor genotype into the care of patients with NSCLC may not require special

  4. Fluidic sampling

    International Nuclear Information System (INIS)

    Houck, E.D.

    1992-01-01

    This paper covers the development of the fluidic sampler and its testing in a fluidic transfer system. The major findings of this paper are as follows. Fluidic jet samples can dependably produce unbiased samples of acceptable volume. The fluidic transfer system with a fluidic sampler in-line will transfer water to a net lift of 37.2--39.9 feet at an average ratio of 0.02--0.05 gpm (77--192 cc/min). The fluidic sample system circulation rate compares very favorably with the normal 0.016--0.026 gpm (60--100 cc/min) circulation rate that is commonly produced for this lift and solution with the jet-assisted airlift sample system that is normally used at ICPP. The volume of the sample taken with a fluidic sampler is dependant on the motive pressure to the fluidic sampler, the sample bottle size and on the fluidic sampler jet characteristics. The fluidic sampler should be supplied with fluid having the motive pressure of the 140--150 percent of the peak vacuum producing motive pressure for the jet in the sampler. Fluidic transfer systems should be operated by emptying a full pumping chamber to nearly empty or empty during the pumping cycle, this maximizes the solution transfer rate

  5. Variational Approach to Enhanced Sampling and Free Energy Calculations

    Science.gov (United States)

    Valsson, Omar; Parrinello, Michele

    2014-08-01

    The ability of widely used sampling methods, such as molecular dynamics or Monte Carlo simulations, to explore complex free energy landscapes is severely hampered by the presence of kinetic bottlenecks. A large number of solutions have been proposed to alleviate this problem. Many are based on the introduction of a bias potential which is a function of a small number of collective variables. However constructing such a bias is not simple. Here we introduce a functional of the bias potential and an associated variational principle. The bias that minimizes the functional relates in a simple way to the free energy surface. This variational principle can be turned into a practical, efficient, and flexible sampling method. A number of numerical examples are presented which include the determination of a three-dimensional free energy surface. We argue that, beside being numerically advantageous, our variational approach provides a convenient and novel standpoint for looking at the sampling problem.

  6. Compressive sampling of polynomial chaos expansions: Convergence analysis and sampling strategies

    International Nuclear Information System (INIS)

    Hampton, Jerrad; Doostan, Alireza

    2015-01-01

    Sampling orthogonal polynomial bases via Monte Carlo is of interest for uncertainty quantification of models with random inputs, using Polynomial Chaos (PC) expansions. It is known that bounding a probabilistic parameter, referred to as coherence, yields a bound on the number of samples necessary to identify coefficients in a sparse PC expansion via solution to an ℓ 1 -minimization problem. Utilizing results for orthogonal polynomials, we bound the coherence parameter for polynomials of Hermite and Legendre type under their respective natural sampling distribution. In both polynomial bases we identify an importance sampling distribution which yields a bound with weaker dependence on the order of the approximation. For more general orthonormal bases, we propose the coherence-optimal sampling: a Markov Chain Monte Carlo sampling, which directly uses the basis functions under consideration to achieve a statistical optimality among all sampling schemes with identical support. We demonstrate these different sampling strategies numerically in both high-order and high-dimensional, manufactured PC expansions. In addition, the quality of each sampling method is compared in the identification of solutions to two differential equations, one with a high-dimensional random input and the other with a high-order PC expansion. In both cases, the coherence-optimal sampling scheme leads to similar or considerably improved accuracy

  7. Compressive sampling of polynomial chaos expansions: Convergence analysis and sampling strategies

    Science.gov (United States)

    Hampton, Jerrad; Doostan, Alireza

    2015-01-01

    Sampling orthogonal polynomial bases via Monte Carlo is of interest for uncertainty quantification of models with random inputs, using Polynomial Chaos (PC) expansions. It is known that bounding a probabilistic parameter, referred to as coherence, yields a bound on the number of samples necessary to identify coefficients in a sparse PC expansion via solution to an ℓ1-minimization problem. Utilizing results for orthogonal polynomials, we bound the coherence parameter for polynomials of Hermite and Legendre type under their respective natural sampling distribution. In both polynomial bases we identify an importance sampling distribution which yields a bound with weaker dependence on the order of the approximation. For more general orthonormal bases, we propose the coherence-optimal sampling: a Markov Chain Monte Carlo sampling, which directly uses the basis functions under consideration to achieve a statistical optimality among all sampling schemes with identical support. We demonstrate these different sampling strategies numerically in both high-order and high-dimensional, manufactured PC expansions. In addition, the quality of each sampling method is compared in the identification of solutions to two differential equations, one with a high-dimensional random input and the other with a high-order PC expansion. In both cases, the coherence-optimal sampling scheme leads to similar or considerably improved accuracy.

  8. Enabling optical metrology on small 5×5μm2 in-cell targets to support flexible sampling and higher order overlay and CD control for advanced logic devices nodes

    Science.gov (United States)

    Salerno, Antonio; de la Fuente, Isabel; Hsu, Zack; Tai, Alan; Chang, Hammer; McNamara, Elliott; Cramer, Hugo; Li, Daoping

    2018-03-01

    In next generation Logic devices, overlay control requirements shrink to sub 2.5nm level on-product overlay. Historically on-product overlay has been defined by the overlay capability of after-develop in-scribe targets. However, due to design and dimension, the after development metrology targets are not completely representative for the final overlay of the device. In addition, they are confined to the scribe-lane area, which limits the sampling possibilities. To address these two issues, metrology on structures matching the device structure and which can be sampled with high density across the device is required. Conventional after-etch CDSEM techniques on logic devices present difficulties in discerning the layers of interest, potential destructive charging effects and finally, they are limited by the long measurement times[1] [2] [3] . All together, limit the sampling densities and making CDSEM less attractive for control applications. Optical metrology can overcome most of these limitations. Such measurement, however, does require repetitive structures. This requirement is not fulfilled by logic devices, as the features vary in pitch and CD over the exposure field. The solution is to use small targets, with a maximum pad size of 5x5um2 , which can easily be placed in the logic cell area. These targets share the process and architecture of the device features of interest, but with a modified design that replicates as close as possible the device layout, allowing for in-device metrology for both CD and Overlay. This solution enables measuring closer to the actual product feature location and, not being limited to scribe-lanes, it opens the possibility of higher-density sampling schemes across the field. In summary, these targets become the facilitator of in-device metrology (IDM), that is, enabling the measurements both in-device Overlay and the CD parameters of interest and can deliver accurate, high-throughput, dense and after-etch measurements for Logic

  9. Global solutions to random 3D vorticity equations for small initial data

    Science.gov (United States)

    Barbu, Viorel; Röckner, Michael

    2017-11-01

    One proves the existence and uniqueness in (Lp (R3)) 3, 3/2 4p - 6)3 with respect to the time variable. Furthermore, we obtain the pathwise continuous dependence of solutions with respect to the initial data. In particular, one gets a locally unique solution of 3D stochastic Navier-Stokes equation in vorticity form up to some explosion stopping time τ adapted to the Brownian motion.

  10. Investigation of the Effect of Small Hardening Spots Created on the Sample Surface by Laser Complex with Solid-State Laser

    Science.gov (United States)

    Nozdrina, O.; Zykov, I.; Melnikov, A.; Tsipilev, V.; Turanov, S.

    2018-03-01

    This paper describes the results of an investigation of the effect of small hardening spots (about 1 mm) created on the surface of a sample by laser complex with solid-state laser. The melted area of the steel sample is not exceed 5%. Steel microhardness change in the region subjected to laser treatment is studied. Also there is a graph of the deformation of samples dependence on the tension. As a result, the yield plateau and plastic properties changes were detected. The flow line was tracked in the series of speckle photographs. As a result we can see how mm surface inhomogeneity can influence on the deformation and strength properties of steel.

  11. Sampling versus systematic full lymphatic dissection in surgical treatment of non-small cell lung cancer.

    Science.gov (United States)

    Koulaxouzidis, Georgios; Karagkiouzis, Grigorios; Konstantinou, Marios; Gkiozos, Ioannis; Syrigos, Konstantinos

    2013-04-22

    The extent of mediastinal lymph node assessment during surgery for non-small cell cancer remains controversial. Different techniques are used, ranging from simple visual inspection of the unopened mediastinum to an extended bilateral lymph node dissection. Furthermore, different terms are used to define these techniques. Sampling is the removal of one or more lymph nodes under the guidance of pre-operative findings. Systematic (full) nodal dissection is the removal of all mediastinal tissue containing the lymph nodes systematically within anatomical landmarks. A Medline search was conducted to identify articles in the English language that addressed the role of mediastinal lymph node resection in the treatment of non-small cell lung cancer. Opinions as to the reasons for favoring full lymphatic dissection include complete resection, improved nodal staging and better local control due to resection of undetected micrometastasis. Arguments against routine full lymphatic dissection are increased morbidity, increase in operative time, and lack of evidence of improved survival. For complete resection of non-small cell lung cancer, many authors recommend a systematic nodal dissection as the standard approach during surgery, and suggest that this provides both adequate nodal staging and guarantees complete resection. Whether extending the lymph node dissection influences survival or recurrence rate is still not known. There are valid arguments in favor in terms not only of an improved local control but also of an improved long-term survival. However, the impact of lymph node dissection on long-term survival should be further assessed by large-scale multicenter randomized trials.

  12. Determination of 35S-aminoacyl-transfer ribonucleic acid specific radioactivity in small tissue samples

    International Nuclear Information System (INIS)

    Samarel, A.M.; Ogunro, E.A.; Ferguson, A.G.; Lesch, M.

    1981-01-01

    Rate determination of protein synthesis utilizing tracer amino acid incorporation requires accurate assessment of the specific radioactivity of the labeled precursor aminoacyl-tRNA pool. Previously published methods presumably useful for the measurement of any aminoacyl-tRNA were unsuccessful when applied to [ 35 S]methionine, due to the unique chemical properties of this amino acid. Herein we describe modifications of these methods necessary for the measurement of 35 S-aminoacyl-tRNA specific radioactivity from small tissue samples incubated in the presence of [ 35 S]methionine. The use of [ 35 S]methionine of high specific radioactivity enables analysis of the methionyl-tRNA from less than 100 mg of tissue. Conditions for optimal recovery of 35 S-labeled dansyl-amino acid derivatives are presented and possible applications of this method are discussed

  13. Brine Sampling and Evaluation Program: Phase 1 report

    International Nuclear Information System (INIS)

    Deal, D.E.; Case, J.B.

    1987-01-01

    This interim report presents preliminary data obtained in the course of the WIPP Brine Sampling and Evaluation Program. The investigations focus on the brine present in the near-field environment around the WIPP underground workings. Although the WIPP underground workings are considered dry, small amounts of brine are present. This amount of brine is not unexpected in rocks of marine sedimentary origin. Part of that brine can and does migrate into the repository in response to pressure gradients, at essentially isothermal conditions. These small volumes of brine have little effect on the day-to-day operations, but are pervasive throughout the repository and may contribute enough moisture over a period of years to affect resaturation and repressurization after sealing and closure. Gas bubbles are observed in many of the brine occurrences. Gas is also known to exsolve from solution as the brine is poured from container to container. 68 refs., 9 figs., 2 tabs

  14. Interparticle interactions and structure in nonideal solutions of human serum albumin studied by small-angle neutron scattering and Monte Carlo simulation

    DEFF Research Database (Denmark)

    Sjöberg, B.; Mortensen, K.

    1994-01-01

    of human serum albumin (HSA) up to a concentration of 0.26 g/cm(3) in 1.08 M NaCl. In order to obtain a model for the interactions we have combined the SANS data with results obtained by Monte Carlo simulations where we calculate the structure factor S(Q) and the pair correlation function g......Moderately or highly concentrated nonideal solutions of macromolecules are very important systems e.g. in biology and in many technical processes. In this work we have used the small-angle neutron scattering technique (SANS) to study the interactions and interparticle structure in solutions......(r). The advantage of using the Monte Carlo method is that completely general models for the particle shape and the interactions can be considered. It is found that the SANS data can be explained by a model where the shape of the HSA molecule is approximated by an ellipsoid of revolution with semiaxes a = 6.8 nm...

  15. Difficulties encountered and solutions found when implementing stereotactic radiotherapy of non-small cell lung cancer

    International Nuclear Information System (INIS)

    Assouline, A.; Halley, A.; Belghith, B.; Mazeron, J.J.; Feuvret, L.

    2012-01-01

    The aim of this paper is to describe the difficulties encountered when implementing stereotactic radiotherapy of non-small cell lung cancer (T1-T2, N0, M0) using a voluntary breath-hold technique. From 25/03/2010 to 22/02/2011, eight patients with a non-small cell lung cancer were selected for treatment. CT images were obtained with the patient maintaining breath-hold using a spirometer. Treatment was delivered when the patient maintains this level of breath-hold. Treatment was performed with a 4 MV and 10 MV photon beams from a linear accelerator Varian 2100CS, equipped with a 120 leaves collimator. 60 Gy or 48 Gy were delivered, in four sessions, to the 80% isodose. The planning target volume (PTV) was defined by adding a 5 mm margin to the internal target volume (ITV), the ITV corresponding to the gross tumour volume (GTV) plus a 3 mm margin. CTV is considered equal to GTV. The non-understanding of the gating technique, the great number of beams and the limited breath-hold times led to the failure of some treatments. It can be explained by some patients insufficient respiratory abilities and the low dose rate of one of the beams used for treatment, thus forcing some radiation fields to be delivered in two or three times. Implementing such a technique can be limited by the patients' physical abilities and the materials used. Some solutions were found: a training phase more intense with a coaching of the breath-hold technique more precise, or the use of an abdominal compression device. (authors)

  16. Open focused microwave-assisted sample preparation for rapid total and mercury species determination in environmental solid samples

    OpenAIRE

    Tseng, C. M.; Garraud, H.; Amouroux, D.; Donard, O. F. X.; de Diego, A.

    1998-01-01

    This paper describes rapid, simple microwave-assisted leaching/ digestion procedures for total and mercury species determination in sediment samples and biomaterials. An open focused microwave system allowed the sample preparation time to be dramatically reduced to only 24 min when a power of 40-80 W was applied. Quantitative leaching of methylmercury from sediments by HNO3 solution and complete dissolution of biomaterials by an alkaline solution, such as 25% TMAH solution, were obtained. Met...

  17. Spinning solutions in general relativity with infinite central density

    Science.gov (United States)

    Flammer, P. D.

    2018-05-01

    This paper presents general relativistic numerical simulations of uniformly rotating polytropes. Equations are developed using MSQI coordinates, but taking a logarithm of the radial coordinate. The result is relatively simple elliptical differential equations. Due to the logarithmic scale, we can resolve solutions with near-singular mass distributions near their center, while the solution domain extends many orders of magnitude larger than the radius of the distribution (to connect with flat space-time). Rotating solutions are found with very high central energy densities for a range of adiabatic exponents. Analytically, assuming the pressure is proportional to the energy density (which is true for polytropes in the limit of large energy density), we determine the small radius behavior of the metric potentials and energy density. This small radius behavior agrees well with the small radius behavior of large central density numerical results, lending confidence to our numerical approach. We compare results with rotating solutions available in the literature, which show good agreement. We study the stability of spherical solutions: instability sets in at the first maximum in mass versus central energy density; this is also consistent with results in the literature, and further lends confidence to the numerical approach.

  18. Preparation of rock samples for measurement of the thermal neutron macroscopic absorption cross-section

    International Nuclear Information System (INIS)

    Czubek, J.A.; Burda, J.; Drozdowicz, K.; Igielski, A.; Kowalik, W.; Krynicka-Drozdowicz, E.; Woznicka, U.

    1986-03-01

    Preparation of rock samples for the measurement of the thermal neutron macroscopic absorption cross-section in small cylindrical two-region systems by a pulsed technique is presented. Requirements which should be fulfilled during the preparation of the samples due to physical assumptions of the method are given. A cylindrical vessel is filled with crushed rock and saturated with a medium strongly absorbing thermal neutrons. Water solutions of boric acid of well-known macroscopic absorption cross-section are used. Mass contributions of the components in the sample are specified. This is necessary for the calculation of the thermal neutron macroscopic absorption cross-section of the rock matrix. The conditions necessary for assuring the required accuracy of the measurement are given and the detailed procedure of preparation of the rock sample is described. (author)

  19. The corrosion resistance of Nitinol alloy in simulated physiological solutions

    International Nuclear Information System (INIS)

    Milošev, Ingrid; Kapun, Barbara

    2012-01-01

    The corrosion behaviour of Nitinol alloy containing nearly equi-atomic composition of nickel and titanium and its constituent metals (nickel and titanium) was investigated in simulated Hanks physiological solution (pH value 7.5) and pH modified simulated Hanks physiological solution (pH values 4.5 and 6.5) and by electrochemical method of anodic potentiodynamic polarization at 37 °C. In this chloride-rich medium the corrosion stability of Nitinol is limited by the susceptibility to localized corrosion and is in that sense more similar to nickel than to titanium. The corrosion stability of Nitinol is strongly dependent on the surface preparation—grinding, polishing or chemical etching. Whereas a ground surface is not resistant to localized corrosion, polished and chemically etched surfaces are resistant to this type of corrosion attack. The reasons for this behaviour were investigated through metallurgical, topographical and chemical properties of the surface as a function of surface preparation. For that purpose, scanning electron microscopy combined with chemical analysis, confocal microscopy and X-ray photoelectron spectroscopy were used. The surface roughness decreased in the following order: chemically etched > ground > polished surface. Besides differences in topography, distinct differences in the chemical composition of the outermost surface are observed. Ground, rough surfaces comprised mainly titanium oxides and small amounts of nickel metal. Chemically etched and, especially, polished surfaces are composed of a mixture of titanium, nickel and titanium oxides, as studied by angle resolved X-ray photoelectron spectroscopy. These results emphasize the importance of detailed investigation of the metal surface since small differences in surface preparation may induce large differences in corrosion stability of material when exposed to corrosive environments. - Highlights: ► The corrosion resistance of Nitinol is dependent on the surface preparation.

  20. On-capillary sample cleanup method for the electrophoretic determination of carbohydrates in juice samples.

    Science.gov (United States)

    Morales-Cid, Gabriel; Simonet, Bartolomé M; Cárdenas, Soledad; Valcárcel, Miguel

    2007-05-01

    On many occasions, sample treatment is a critical step in electrophoretic analysis. As an alternative to batch procedures, in this work, a new strategy is presented with a view to develop an on-capillary sample cleanup method. This strategy is based on the partial filling of the capillary with carboxylated single-walled carbon nanotube (c-SWNT). The nanoparticles retain interferences from the matrix allowing the determination and quantification of carbohydrates (viz glucose, maltose and fructose). The precision of the method for the analysis of real samples ranged from 5.3 to 6.4%. The proposed method was compared with a method based on a batch filtration of the juice sample through diatomaceous earth and further electrophoretic determination. This method was also validated in this work. The RSD for this other method ranged from 5.1 to 6%. The results obtained by both methods were statistically comparable demonstrating the accuracy of the proposed methods and their effectiveness. Electrophoretic separation of carbohydrates was achieved using 200 mM borate solution as a buffer at pH 9.5 and applying 15 kV. During separation, the capillary temperature was kept constant at 40 degrees C. For the on-capillary cleanup method, a solution containing 50 mg/L of c-SWNTs prepared in 300 mM borate solution at pH 9.5 was introduced for 60 s into the capillary just before sample introduction. For the electrophoretic analysis of samples cleaned in batch with diatomaceous earth, it is also recommended to introduce into the capillary, just before the sample, a 300 mM borate solution as it enhances the sensitivity and electrophoretic resolution.

  1. Highly eccentric hip-hop solutions of the 2 N-body problem

    Science.gov (United States)

    Barrabés, Esther; Cors, Josep M.; Pinyol, Conxita; Soler, Jaume

    2010-02-01

    We show the existence of families of hip-hop solutions in the equal-mass 2 N-body problem which are close to highly eccentric planar elliptic homographic motions of 2 N bodies plus small perpendicular non-harmonic oscillations. By introducing a parameter ɛ, the homographic motion and the small amplitude oscillations can be uncoupled into a purely Keplerian homographic motion of fixed period and a vertical oscillation described by a Hill type equation. Small changes in the eccentricity induce large variations in the period of the perpendicular oscillation and give rise, via a Bolzano argument, to resonant periodic solutions of the uncoupled system in a rotating frame. For small ɛ≠0, the topological transversality persists and Brouwer’s fixed point theorem shows the existence of this kind of solutions in the full system.

  2. Sampling of finite elements for sparse recovery in large scale 3D electrical impedance tomography

    International Nuclear Information System (INIS)

    Javaherian, Ashkan; Moeller, Knut; Soleimani, Manuchehr

    2015-01-01

    This study proposes a method to improve performance of sparse recovery inverse solvers in 3D electrical impedance tomography (3D EIT), especially when the volume under study contains small-sized inclusions, e.g. 3D imaging of breast tumours. Initially, a quadratic regularized inverse solver is applied in a fast manner with a stopping threshold much greater than the optimum. Based on assuming a fixed level of sparsity for the conductivity field, finite elements are then sampled via applying a compressive sensing (CS) algorithm to the rough blurred estimation previously made by the quadratic solver. Finally, a sparse inverse solver is applied solely to the sampled finite elements, with the solution to the CS as its initial guess. The results show the great potential of the proposed CS-based sparse recovery in improving accuracy of sparse solution to the large-size 3D EIT. (paper)

  3. Effect of solution composition on the adsorption and desorption of 137Cs on forest soils

    International Nuclear Information System (INIS)

    Staunton, S.; Wells, C.; Shaw, G.

    2004-01-01

    There is ongoing debate as to the pertinence of measurements of soil-liquid distribution coefficients in dilute suspension to the understanding and the prediction of the mobility of radionuclides in soil. This debate is particularly active in the case of radiocaesium. Several factors could cause significant discrepancies between measured and effective in situ distributions of radiocaesium. 1. Differences in solution composition, notably ionic strength and concentration in cations such as potassium and ammonium; 2. Differences in soil:solution ratio; 3. Time dependent reactions; 4. Reversibility of the adsorption reaction; 5. Concentration dependence of adsorption. We have attempted to assess the importance of some of these factors by studying 137 Cs adsorption on soils sampled from different horizons of a forest soil. Kd was measured in suspension. Soil:solution ratio and initial 137 Cs concentration and concentration of potassium and stable Cs in solution were varied. Adsorption and desorption Kd values were measured under similar conditions and compared. Kd values were in the lower range of values reported in the literature (5-30 1/kg). Samples from surface layers showed no concentration dependence at trace additions of 137 Cs, whereas some decrease in Kd was observed with increasing 137 Cs concentration on the Ea horizon. Data obtained at different soil:solution ratios all fell on the same adsorption isotherms as those obtained by varying initial 137 Cs concentration. Stable caesium and, to a lesser extent, potassium inhibited 137 Cs adsorption. This effect was greater in the Ea horizon than the surface soils, probably due to the mineral content. For all samples the desorption Kd was greater than the adsorption Kd in the same solution, indicating a small but significant degree of irreversibility. (author)

  4. Intrinsic neutron source strengths in uranium solutions

    International Nuclear Information System (INIS)

    Anderson, R.E.; Robba, A.A.; Seale, R.L.; Rutherford, D.A.; Butterfield, K.B.; Brunson, G.S.

    1991-01-01

    Neutron production rates for 5% enriched uranyl fluoride and 93% uranyl nitrate solutions have been measured using a high-efficiency neutron well counter. Measurements were made for both solution types as a function of sample volume. These results were extrapolated to zero sample volume to eliminate sample size effects, such as multiplication and absorption. For the 5% enriched uranyl fluoride solution, a neutron production rate of 0.0414 ± 0.0041 n/s/ml was measured; for the 93% enriched uranyl nitrate solution, a neutron production rate of 0.0232 ± 0.0023 n/s/ml was measured. The biggest uncertainty is in measuring the detector efficiency, and further work on this aspect of the experiment is planned. Calculations for the neutron production rates based on measured thick-target (alpha, n) production rates and shown alpha stopping powers are in reasonable agreement with the data for the uranyl nitrate solution, but are in poor agreement with the data for the uranyl fluoride solution. 8 refs., 7 figs., 5 tabs

  5. A combined Importance Sampling and Kriging reliability method for small failure probabilities with time-demanding numerical models

    International Nuclear Information System (INIS)

    Echard, B.; Gayton, N.; Lemaire, M.; Relun, N.

    2013-01-01

    Applying reliability methods to a complex structure is often delicate for two main reasons. First, such a structure is fortunately designed with codified rules leading to a large safety margin which means that failure is a small probability event. Such a probability level is difficult to assess efficiently. Second, the structure mechanical behaviour is modelled numerically in an attempt to reproduce the real response and numerical model tends to be more and more time-demanding as its complexity is increased to improve accuracy and to consider particular mechanical behaviour. As a consequence, performing a large number of model computations cannot be considered in order to assess the failure probability. To overcome these issues, this paper proposes an original and easily implementable method called AK-IS for active learning and Kriging-based Importance Sampling. This new method is based on the AK-MCS algorithm previously published by Echard et al. [AK-MCS: an active learning reliability method combining Kriging and Monte Carlo simulation. Structural Safety 2011;33(2):145–54]. It associates the Kriging metamodel and its advantageous stochastic property with the Importance Sampling method to assess small failure probabilities. It enables the correction or validation of the FORM approximation with only a very few mechanical model computations. The efficiency of the method is, first, proved on two academic applications. It is then conducted for assessing the reliability of a challenging aerospace case study submitted to fatigue.

  6. Reducing Transaction Costs for Energy Efficiency Investments and Analysis of Economic Risk Associated With Building Performance Uncertainties: Small Buildings and Small Portfolios Program

    Energy Technology Data Exchange (ETDEWEB)

    Langner, R.; Hendron, B.; Bonnema, E.

    2014-08-01

    The small buildings and small portfolios (SBSP) sector face a number of barriers that inhibit SBSP owners from adopting energy efficiency solutions. This pilot project focused on overcoming two of the largest barriers to financing energy efficiency in small buildings: disproportionately high transaction costs and unknown or unacceptable risk. Solutions to these barriers can often be at odds, because inexpensive turnkey solutions are often not sufficiently tailored to the unique circumstances of each building, reducing confidence that the expected energy savings will be achieved. To address these barriers, NREL worked with two innovative, forward-thinking lead partners, Michigan Saves and Energi, to develop technical solutions that provide a quick and easy process to encourage energy efficiency investments while managing risk. The pilot project was broken into two stages: the first stage focused on reducing transaction costs, and the second stage focused on reducing performance risk. In the first stage, NREL worked with the non-profit organization, Michigan Saves, to analyze the effects of 8 energy efficiency measures (EEMs) on 81 different baseline small office building models in Holland, Michigan (climate zone 5A). The results of this analysis (totaling over 30,000 cases) are summarized in a simple spreadsheet tool that enables users to easily sort through the results and find appropriate small office EEM packages that meet a particular energy savings threshold and are likely to be cost-effective.

  7. Precise Th/U-dating of small and heavily coated samples of deep sea corals

    Science.gov (United States)

    Lomitschka, Michael; Mangini, Augusto

    1999-07-01

    Marine carbonate skeletons like deep-sea corals are frequently coated with iron and manganese oxides/hydroxides which adsorb additional thorium and uranium out of the sea water. A new cleaning procedure has been developed to reduce this contamination. In this further cleaning step a solution of Na 2EDTA (Na 2H 2T B) and ascorbic acid is used which composition is optimised especially for samples of 20 mg of weight. It was first tested on aliquots of a reef-building coral which had been artificially contaminated with powdered ferromanganese nodule. Applied on heavily contaminated deep-sea corals (scleractinia), it reduced excess 230Th by another order of magnitude in addition to usual cleaning procedures. The measurement of at least three fractions of different contamination, together with an additional standard correction for contaminated carbonates results in Th/U-ages corrected for the authigenic component. A good agreement between Th/U- and 14C-ages can be achieved even for extremely coated corals.

  8. Small angle neutron scattering and small angle X-ray scattering ...

    Indian Academy of Sciences (India)

    Abstract. The morphology of carbon nanofoam samples comprising platinum nanopar- ticles dispersed in the matrix was characterized by small angle neutron scattering (SANS) and small angle X-ray scattering (SAXS) techniques. Results show that the structure of pores of carbon matrix exhibits a mass (pore) fractal nature ...

  9. Predicting Antitumor Activity of Peptides by Consensus of Regression Models Trained on a Small Data Sample

    Directory of Open Access Journals (Sweden)

    Ivanka Jerić

    2011-11-01

    Full Text Available Predicting antitumor activity of compounds using regression models trained on a small number of compounds with measured biological activity is an ill-posed inverse problem. Yet, it occurs very often within the academic community. To counteract, up to some extent, overfitting problems caused by a small training data, we propose to use consensus of six regression models for prediction of biological activity of virtual library of compounds. The QSAR descriptors of 22 compounds related to the opioid growth factor (OGF, Tyr-Gly-Gly-Phe-Met with known antitumor activity were used to train regression models: the feed-forward artificial neural network, the k-nearest neighbor, sparseness constrained linear regression, the linear and nonlinear (with polynomial and Gaussian kernel support vector machine. Regression models were applied on a virtual library of 429 compounds that resulted in six lists with candidate compounds ranked by predicted antitumor activity. The highly ranked candidate compounds were synthesized, characterized and tested for an antiproliferative activity. Some of prepared peptides showed more pronounced activity compared with the native OGF; however, they were less active than highly ranked compounds selected previously by the radial basis function support vector machine (RBF SVM regression model. The ill-posedness of the related inverse problem causes unstable behavior of trained regression models on test data. These results point to high complexity of prediction based on the regression models trained on a small data sample.

  10. Sediment control - an appropriate solution for small irrigation channels

    International Nuclear Information System (INIS)

    Shoag, M.A.

    2002-01-01

    Sediment control is one of the key factors considered prior to the design of an irrigation channel. When the channel takes off from its headworks, its slope is usually smaller than that of the parent stream to obtain required head. If the sediment load is heavy then the channel can not maintain equilibrium since the high influx can not be transported fully due to its small gradient. This results in the deposition of part incoming sediment in the channel itself. A typical irrigation intake suitable for small schemes, which consists of a simple settling basin with double orifice: one at the inlet from the river and the other at the outlet to the canal. The basin is provided with a side spill weir near its downstream end, to discharge flows in excess of the maximum canal capacity. This paper deals with the experimental study of such an arrangement. Different flows were run covering a range of levels in the river, from minimum to flood flows to check the hydraulic performance of the layout and in particular to study its effectiveness in settling sediment at low flows and avoiding excessive sediment input to the canal during flood. (author)

  11. Focused-microwave-assisted sample preparation (M8)

    International Nuclear Information System (INIS)

    Nobrega, J.A.; Santos, D.M.; Trevizan, L.C.; Costa, L.M.; Nogueira, A.R.A.

    2002-01-01

    Full text: Focused-microwave-assisted sample preparation is a suitable strategy when dealing with high masses of organic samples. However, the final acid concentration of the digestate can difficult routine analytical measurements using spectroscopic techniques. Acids could be evaporated, but this step could be slow even when using microwave-assisted heating and requires a scrubber system for acid vapor collection and neutralization. We are investigating two procedures to decrease the acid concentration of digestates. The first one is based on acid vapor phase digestion of samples contained in PTFE devices' inserted into the microwave flask. The acid solution is heated by absorption of microwave radiation, then the acid vapor partially condenses in the upper part of the reaction flask and it is partially collected in each sample container. Calcium, Fe, Mg, Mn, and Zn were quantitatively recovered in samples of animal and vegetable tissues. Better recoveries were attained when adding a small volume of sodium hypochlorite to the sample. This effect is probably related to the generation of chlorine in the sample container after collecting condensed acid. The second procedure developed is based on the gradual addition of liquid samples to a previously heated acid digestion mixture. This procedure was successfully applied for digestion of milk, fruit juices, and red wine. The main advantage is the possibility of digesting up to four-fold more sample using up to ten-fold lower amounts of concentrated acids. Results obtained using both digestion procedures and measurements by ICP-OES with axial view will be presented. (author)

  12. Energy efficient design of cognitive small cells

    NARCIS (Netherlands)

    Wildemeersch, Matthias; Wildemeersch, Matthias; Quek, Tony Q.S.; Rabbachin, Alberto; Slump, Cornelis H.; Huang, Aiping; Kim, Dong-In; Mueller, P.

    2013-01-01

    Heterogeneous networks consisting of a macrocell tier and a small cell tier are considered an attractive solution to cope with the fierce increase of mobile traffic demand. Nevertheless, a massive deployment of small cell access points (SAPs) leads also to a considerable increase in energy

  13. MaxEnt’s parameter configuration and small samples: are we paying attention to recommendations? A systematic review

    Directory of Open Access Journals (Sweden)

    Narkis S. Morales

    2017-03-01

    Full Text Available Environmental niche modeling (ENM is commonly used to develop probabilistic maps of species distribution. Among available ENM techniques, MaxEnt has become one of the most popular tools for modeling species distribution, with hundreds of peer-reviewed articles published each year. MaxEnt’s popularity is mainly due to the use of a graphical interface and automatic parameter configuration capabilities. However, recent studies have shown that using the default automatic configuration may not be always appropriate because it can produce non-optimal models; particularly when dealing with a small number of species presence points. Thus, the recommendation is to evaluate the best potential combination of parameters (feature classes and regularization multiplier to select the most appropriate model. In this work we reviewed 244 articles published between 2013 and 2015 to assess whether researchers are following recommendations to avoid using the default parameter configuration when dealing with small sample sizes, or if they are using MaxEnt as a “black box tool.” Our results show that in only 16% of analyzed articles authors evaluated best feature classes, in 6.9% evaluated best regularization multipliers, and in a meager 3.7% evaluated simultaneously both parameters before producing the definitive distribution model. We analyzed 20 articles to quantify the potential differences in resulting outputs when using software default parameters instead of the alternative best model. Results from our analysis reveal important differences between the use of default parameters and the best model approach, especially in the total area identified as suitable for the assessed species and the specific areas that are identified as suitable by both modelling approaches. These results are worrying, because publications are potentially reporting over-complex or over-simplistic models that can undermine the applicability of their results. Of particular importance

  14. Classical solutions for a one phase osmosis model

    NARCIS (Netherlands)

    Lippoth, F.; Prokert, G.

    2011-01-01

    For a moving boundary problem modelling the motion of a semipermeable membrane by osmotic pressure and surface tension we prove the existence and uniqueness of classical solutions on small time intervals. Moreover, we construct solutions existing on arbitrary long time intervals, provided the

  15. Scaling laws and accurate small-amplitude stationary solution for the motion of a planar vortex filament in the Cartesian form of the local induction approximation.

    Science.gov (United States)

    Van Gorder, Robert A

    2013-04-01

    We provide a formulation of the local induction approximation (LIA) for the motion of a vortex filament in the Cartesian reference frame (the extrinsic coordinate system) which allows for scaling of the reference coordinate. For general monotone scalings of the reference coordinate, we derive an equation for the planar solution to the derivative nonlinear Schrödinger equation governing the LIA. We proceed to solve this equation perturbatively in small amplitude through an application of multiple-scales analysis, which allows for accurate computation of the period of the planar vortex filament. The perturbation result is shown to agree strongly with numerical simulations, and we also relate this solution back to the solution obtained in the arclength reference frame (the intrinsic coordinate system). Finally, we discuss nonmonotone coordinate scalings and their application for finding self-intersections of vortex filaments. These self-intersecting vortex filaments are likely unstable and collapse into other structures or dissipate completely.

  16. Effect of Intravenous Small-Volume Hypertonic Sodium Bicarbonate, Sodium Chloride, and Glucose Solutions in Decreasing Plasma Potassium Concentration in Hyperkalemic Neonatal Calves with Diarrhea.

    Science.gov (United States)

    Trefz, F M; Constable, P D; Lorenz, I

    2017-05-01

    Hyperkalemia is a frequently observed electrolyte imbalance in dehydrated neonatal diarrheic calves that can result in skeletal muscle weakness and life-threatening cardiac conduction abnormalities and arrhythmias. Intravenous administration of a small-volume hypertonic NaHCO 3 solution is clinically more effective in decreasing the plasma potassium concentration (cK) in hyperkalemic diarrheic calves than hypertonic NaCl or glucose solutions. Twenty-two neonatal diarrheic calves with cK >5.8 mmol/L. Prospective randomized clinical trial. Calves randomly received either 8.4% NaHCO 3 (6.4 mL/kg BW; n = 7), 7.5% NaCl (5 mL/kg BW; n = 8), or 46.2% glucose (5 mL/kg BW; n = 7) IV over 5 minutes and were subsequently allowed to suckle 2 L of an electrolyte solution. Infusions with NaHCO 3 and NaCl provided an identical sodium load of 6.4 mmol/kg BW. Hypertonic NaHCO 3 infusions produced an immediate and sustained decrease in plasma cK. Hypertonic glucose infusions resulted in marked hyperglycemia and hyperinsulinemia, but cK remained unchanged for 20 minutes. Between 30 and 120 minutes after initiation of treatment, the most marked decrements in cK from baseline occurred in group NaHCO 3 , which were significantly (P < .05) larger during this period of time than in calves in group NaCl, but not group glucose. After 120 minutes, the mean decrease in cK from baseline was -26 ± 10%, -9 ± 8%, and -22 ± 6% in groups NaHCO 3 , NaCl, and glucose, respectively. Small-volume hypertonic NaHCO 3 infusions appear to have clinical advantages for the rapid resuscitation of hyperkalemic diarrheic calves, compared to hypertonic NaCl or glucose solutions. Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

  17. CHARACTERIZATION AND ACTUAL WASTE TEST WITH TANK 5F SAMPLES

    International Nuclear Information System (INIS)

    Fletcher, D.

    2007-01-01

    during the cleaning test with oxalic acid along with the iron, aluminum, and sodium in the sludge. During the neutralization of the oxalic acid, the majority of the uranium precipitates from solution along with the iron and other typical sludge elements. The CSEM results of the 75 C neutralization test provide some evidence of uranium separation from other sludge elements. However, the CSEM analysis looked at a very small amount of sample, which might not be representative of the bulk material and the sludge sample also showed areas of high uranium concentration. Additionally, how the test results will scale to the full-scale neutralization in a waste tank remains uncertain. The analysis of the oxalic acid filtrates indicates that only a small portion of the plutonium dissolved during the tank cleaning test. However, the analytical data from the solid residues filtered from the cleaning test contradict the solution data and indicate approximately half of the plutonium dissolved

  18. Versatile application of indirect Fourier transformation to structure factor analysis: from X-ray diffraction of molecular liquids to small angle scattering of protein solutions.

    Science.gov (United States)

    Fukasawa, Toshiko; Sato, Takaaki

    2011-02-28

    We highlight versatile applicability of a structure-factor indirect Fourier transformation (IFT) technique, hereafter called SQ-IFT. The original IFT aims at the pair distance distribution function, p(r), of colloidal particles from small angle scattering of X-rays (SAXS) and neutrons (SANS), allowing the conversion of the experimental form factor, P(q), into a more intuitive real-space spatial autocorrelation function. Instead, SQ-IFT is an interaction potential model-free approach to the 'effective' or 'experimental' structure factor to yield the pair correlation functions (PCFs), g(r), of colloidal dispersions like globular protein solutions for small-angle scattering data as well as the radial distribution functions (RDFs) of molecular liquids in liquid diffraction (LD) experiments. We show that SQ-IFT yields accurate RDFs of liquid H(2)O and monohydric alcohol reflecting their local intermolecular structures, in which q-weighted structure function, qH(q), conventionally utilized in many LD studies out of necessity of performing direct Fourier transformation, is no longer required. We also show that SQ-IFT applied to theoretically calculated structure factors for uncharged and charged colloidal dispersions almost perfectly reproduces g(r) obtained as a solution of the Ornstein-Zernike (OZ) equation. We further demonstrate the relevance of SQ-IFT in its practical applications, using SANS effective structure factors of lysozyme solutions reported in recent literatures which revealed the equilibrium cluster formation due to coexisting long range electrostatic repulsion and short range attraction between the proteins. Finally, we present SAXS experiments on human serum albumin (HSA) at different ionic strength and protein concentration, in which we discuss the real space picture of spatial distributions of the proteins via the interaction potential model-free route.

  19. The effect of sample preparation methods on glass performance

    International Nuclear Information System (INIS)

    Oh, M.S.; Oversby, V.M.

    1990-01-01

    A series of experiments was conducted using SRL 165 synthetic waste glass to investigate the effects of surface preparation and leaching solution composition on the alteration of the glass. Samples of glass with as-cast surfaces produced smooth reaction layers and some evidence for precipitation of secondary phases from solution. Secondary phases were more abundant in samples reacted in deionized water than for those reacted in a silicate solution. Samples with saw-cut surfaces showed a large reduction in surface roughness after 7 days of reaction in either solution. Reaction in silicate solution for up to 91 days produced no further change in surface morphology, while reaction in DIW produced a spongy surface that formed the substrate for further surface layer development. The differences in the surface morphology of the samples may create microclimates that control the details of development of alteration layers on the glass; however, the concentrations of elements in leaching solutions show differences of 50% or less between samples prepared with different surface conditions for tests of a few months duration. 6 refs., 7 figs., 1 tab

  20. Synthesis and Rheological Properties of an Associative Star Polymer in Aqueous Solutions

    DEFF Research Database (Denmark)

    Hietala, Sami; Mononen, Pekka; Strandman, Satu

    2007-01-01

    synthesised by atom transfer radical. polymerization (ATRP) was found to fonn hydrogels at room temperature at polymer concentrations. Cp, over 22 gIL due to the interpolymer drophobic association of the PS blocks. Increasing Cp leads to stronger elastic networks at room temperature that show a gel......Rheological properties of aqueous solutions and hydrogels fonned by an amphiphiIic star block copolymer poly(acrylic acid)-blockpolystyrene (PAAS4-b-PS6)4. were investigated as a function of the polymer concentration (Cp), temperature, and added saIt concentration. The water-soluble polymer......-to-solution transition with increasing temperature. Increase of ionic strength decreases the moduli compared with the pure hydrogel but did not affect the gel-sol transition temperature significantly. Small-angle X-ray experiments showed two distinct scattering correlation peaks for samples above the gelling Cp, which...

  1. A Mathematical Model of Solute Coupled Water Transport in Toad Intestine Incorporating Recirculation of the Actively Transported Solute

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Sørensen, Jakob Balslev; Sørensen, Jens Nørkær

    2000-01-01

    those of tight junction and interspace basement membrane by convection-diffusion. With solute permeability of paracellular pathway large relative to paracellular water flow, the paracellular flux ratio of the solute (influx/outflux) is small (2-4) in agreement with experiments. The virtual solute......A mathematical model of an absorbing leaky epithelium is developed for analysis of solute coupled water transport. The non-charged driving solute diffuses into cells and is pumped from cells into the lateral intercellular space (lis). All membranes contain water channels with the solute passing...... increases with hydraulic conductance of the pathway carrying water from mucosal solution into lis. Uphill water transport is accomplished, but with high hydraulic conductance of cell membranes strength of transport is obscured by water flow through cells. Anomalous solvent drag occurs when back flux...

  2. Feasibility study on small modular reactors for modern microgrids

    Energy Technology Data Exchange (ETDEWEB)

    Islam, R.; Gabbar, H.A., E-mail: hossam.gabbar@uoit.ca [Univ. of Ontario Inst. of Technology, Faculty of Energy Systems and Nuclear Science, Oshawa, Ontario (Canada)

    2013-07-01

    Microgrid is a solution of conventional power grid problem and offer sustainable decentralized power system. Microgrid with modern distributed energy resources (DER) could play an important role to alleviate dependency on the main electricity grid. Distributed energy resource comprises wind turbine, solar photovoltaic, diesel generator, gas engine, micro turbine, fuel cells, etc.Due to the gap between typical loads and supply within microgrid, larger scale energy generation could provide a possible solution to balance power demand and supply. Feasibility study of Small Nuclear Power Plant, such as Small Modular reactor (SMR), within microgrids could be achieved via different cases. To achieve the target, a comprehensive feasibility study is conducted on microgrid with SMR through electricity generation profiles, geographical and environmental assessment, as well as cost analysis using simulation practices and data analysis.Also potency of SMRs is analyzed. Parameters and Key Performance Indicators (KPIs) could be analyzed to achieve feasible solution of microgrids with small modular reactor (SMR) to improve the overall microgrid performance.The study shows that SMR could be a feasible solution if microgrid parameters are selected properly. (author)

  3. Feasibility study on small modular reactors for modern microgrids

    International Nuclear Information System (INIS)

    Islam, R.; Gabbar, H.A.

    2013-01-01

    Microgrid is a solution of conventional power grid problem and offer sustainable decentralized power system. Microgrid with modern distributed energy resources (DER) could play an important role to alleviate dependency on the main electricity grid. Distributed energy resource comprises wind turbine, solar photovoltaic, diesel generator, gas engine, micro turbine, fuel cells, etc.Due to the gap between typical loads and supply within microgrid, larger scale energy generation could provide a possible solution to balance power demand and supply. Feasibility study of Small Nuclear Power Plant, such as Small Modular reactor (SMR), within microgrids could be achieved via different cases. To achieve the target, a comprehensive feasibility study is conducted on microgrid with SMR through electricity generation profiles, geographical and environmental assessment, as well as cost analysis using simulation practices and data analysis.Also potency of SMRs is analyzed. Parameters and Key Performance Indicators (KPIs) could be analyzed to achieve feasible solution of microgrids with small modular reactor (SMR) to improve the overall microgrid performance.The study shows that SMR could be a feasible solution if microgrid parameters are selected properly. (author)

  4. Orbital Resonances in the Vinti Solution

    Science.gov (United States)

    Zurita, L. D.

    As space becomes more congested, contested, and competitive, high-accuracy orbital predictions become critical for space operations. Current orbit propagators use the two-body solution with perturbations added, which have significant error growth when numerically integrated for long time periods. The Vinti Solution is a more accurate model than the two-body problem because it also accounts for the equatorial bulge of the Earth. Unfortunately, the Vinti solution contains small divisors near orbital resonances in the perturbative terms of the Hamiltonian, which lead to inaccurate orbital predictions. One approach to avoid the small divisors is to apply transformation theory, which is presented in this research. The methodology of this research is to identify the perturbative terms of the Vinti Solution, perform a coordinate transformation, and derive the new equations of motion for the Vinti system near orbital resonances. An analysis of these equations of motion offers insight into the dynamics found near orbital resonances. The analysis in this research focuses on the 2:1 resonance, which includes the Global Positioning System. The phase portrait of a nominal Global Positioning System satellite orbit is found to contain a libration region and a chaotic region. Further analysis shows that the dynamics of the 2:1 resonance affects orbits with semi-major axes ranging from -5.0 to +5.4 kilometers from an exactly 2:1 resonant orbit. Truth orbits of seven Global Positioning System satellites are produced for 10 years. Two of the satellites are found to be outside of the resonance region and three are found to be influenced by the libration dynamics of the resonance. The final satellite is found to be influenced by the chaotic dynamics of the resonance. This research provides a method of avoiding the small divisors found in the perturbative terms of the Vinti Solution near orbital resonances.

  5. Influence of immersion freezing in NaCl solutions and of frozen storage on the viscoelastic behavior of mozzarella cheese.

    Science.gov (United States)

    Ribero, G G; Rubiolo, A C; Zorrilla, S E

    2007-06-01

    The freezing of Mozzarella cheese by immersion in NaCl solutions may be an innovative procedure for the dairy industry because it combines conveniently salting and freezing processes. In this work, the influence of this type of freezing method and of the frozen storage of samples on the viscoelastic behavior of Mozzarella cheese was studied. Slabs (2 x 10 x 10 cm(3)) were immersed in 23% w/w NaCl solutions (control samples: 4 degrees C, 90 min; frozen samples: -15 degrees C, 180 min). Half of the frozen samples were immediately thawed at 4 degrees C . The other half was stored at -20 degrees C for 2 mo and then was thawed at 4 degrees C (frozen-stored samples). Samples were stored at 4 degrees C and assayed at 1, 7, 14, 20, 27, 34, and 41 d. Rheological tests were carried out in oscillatory mode (parallel-plate geometry, diameter: 20 mm, gap: 1 mm, frequency: 1 Hz). Strain sweeps were run (0.001 immersion freezing of Mozzarella cheese affects some of the studied parameters, the differences observed between frozen and frozen-stored samples with control samples were small. Therefore, it was considered that the immersion freezing might be useful for the manufacture and commercialization of Mozzarella cheese.

  6. A new method to measure intestinal secretion using fluorescein isothiocyanate-inulin in small bowel of rats.

    Science.gov (United States)

    Munoz-Abraham, Armando Salim; Judeeba, Sami; Alkukhun, Abedalrazaq; Alfadda, Tariq; Patron-Lozano, Roger; Rodriguez-Davalos, Manuel I; Geibel, John P

    2015-08-01

    Small intestine ischemia can be seen in various conditions such as intestinal transplantation. To further understand the pathologic disruption in ischemia-reperfusion injury, we have developed a method to measure fluid changes in the intestinal lumen of rats. Two 10-cm rat intestine segments were procured, connected to the terminal apertures of a perfusion device, and continuously infused with 3 mL of HEPES solution (control solution) containing 50 μM of fluorescein isothiocyanate (FITC)-inulin. The perfusion device consists of concentric chambers that contain the perfused bowel segments, which are maintained at 37°C via H₂O bath. The individual chamber has four apertures as follows: two fill and/or drain the surrounding HEPES solution on the blood side of the tissue. The others provide flow of HEPES solution containing FITC-inulin through the lumens. The experimental intestine was infused with the same solution with 100 μM of Forskolin. A pump continuously circulated solutions at 6 mL/min. Samples were collected at 15-min intervals until 150 min and were measured by the nanoflourospectrometer. A mean of 6-μM decrease in the FITC-inulin concentration in the Forskolin-treated experimental intestine was observed in comparison with that in the control intestine. The FITC-inulin count dilution in the experimental intestine is a result of an increase of fluid secretion produced by the effect of Forskolin, with P values inulin to allow real-time determinations of fluid and/or electrolyte movement along the small intestine. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. A high-efficiency neutron coincidence counter for small samples

    International Nuclear Information System (INIS)

    Miller, M.C.; Menlove, H.O.; Russo, P.A.

    1991-01-01

    The inventory sample coincidence counter (INVS) has been modified to enhance its performance. The new design is suitable for use with a glove box sample-well (in-line application) as well as for use in the standard at-line mode. The counter has been redesigned to count more efficiently and be less sensitive to variations in sample position. These factors lead to a higher degree of precision and accuracy in a given counting period and allow for the practical use of the INVS counter with gamma-ray isotopics to obtain a plutonium assay independent of operator declarations and time-consuming chemicals analysis. A calculation study was performed using the Los Alamos transport code MCNP to optimize the design parameters. 5 refs., 7 figs., 8 tabs

  8. Choosing a suitable sample size in descriptive sampling

    International Nuclear Information System (INIS)

    Lee, Yong Kyun; Choi, Dong Hoon; Cha, Kyung Joon

    2010-01-01

    Descriptive sampling (DS) is an alternative to crude Monte Carlo sampling (CMCS) in finding solutions to structural reliability problems. It is known to be an effective sampling method in approximating the distribution of a random variable because it uses the deterministic selection of sample values and their random permutation,. However, because this method is difficult to apply to complex simulations, the sample size is occasionally determined without thorough consideration. Input sample variability may cause the sample size to change between runs, leading to poor simulation results. This paper proposes a numerical method for choosing a suitable sample size for use in DS. Using this method, one can estimate a more accurate probability of failure in a reliability problem while running a minimal number of simulations. The method is then applied to several examples and compared with CMCS and conventional DS to validate its usefulness and efficiency

  9. Mastering Microsoft Windows Small Business Server 2008

    CERN Document Server

    Johnson, Steven

    2010-01-01

    A complete, winning approach to the number one small business solution. Do you have 75 or fewer users or devices on your small-business network? Find out how to integrate everything you need for your mini-enterprise with Microsoft's new Windows Server 2008 Small Business Server, a custom collection of server and management technologies designed to help small operations run smoothly without a giant IT department. This comprehensive guide shows you how to master all SBS components as well as handle integration with other Microsoft technologies.: Focuses on Windows Server 2008 Small Business Serv

  10. Going Extreme For Small Solutions To Big Environmental Challenges

    Energy Technology Data Exchange (ETDEWEB)

    Bagwell, Christopher E.

    2011-03-31

    This chapter is devoted to the scale, scope, and specific issues confronting the cleanup and long-term disposal of the U.S. nuclear legacy generated during WWII and the Cold War Era. The research reported is aimed at complex microbiological interactions with legacy waste materials generated by past nuclear production activities in the United States. The intended purpose of this research is to identify cost effective solutions to the specific problems (stability) and environmental challenges (fate, transport, exposure) in managing and detoxifying persistent contaminant species. Specifically addressed are high level waste microbiology and bacteria inhabiting plutonium laden soils in the unsaturated subsurface.

  11. Composition and method for solution mining of uranium ores

    International Nuclear Information System (INIS)

    Lawes, B.C.; Watts, J.C.

    1981-01-01

    It has been found that, in the solution mining of uranium ores using ammonium carbonate solutions containing hydrogen peroxide or ozone as an oxidant, the tendency of the formation being treated to become less permeable during the leaching process can be overcome by including in the leaching solution a very small concentration of sodium silicate

  12. Analysis of liquid samples using dried-droplet laser ablation inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Do, Trong-Mui; Hsieh, Hui-Fang; Chang, Wei-Ciang [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, 30013 Taiwan (China); Chang, E.-E. [Department of Biochemistry, Taipei Medical University, Taipei City, 11031 Taiwan (China); Wang, Chu-Fang, E-mail: cfwang@mx.nthu.edu.tw [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, 30013 Taiwan (China); Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2011-08-15

    In this study we developed a dried-droplet method for laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The proposed method provides accurate and precise results when building calibration curves and determining elements of interest in real liquid samples. After placing just 1 {mu}L of a liquid standard solution or a real sample onto the filter surface and then converting the solution into a very small, thin dry spot, the sample could be applied as an analytical subject for LA. To demonstrate the feasibility of this proposed method, we used LA-ICP-MS and conventional ICP-MS to determine the levels of 13 elements (Li, V, Mn, Co, Ni, Cu, Zn, As, Mo, Cd, Sb, Tl, and Pb) in five water samples. The correlation coefficients obtained from the various calibration curves ranged from 0.9920 ({sup 205}Tl) to 0.9998 ({sup 51}V), sufficient to allow the determination of a wide range of elements in the samples. We also investigated the effects of Methylene Blue (MB) and the NaCl concentration on the elemental analyses. MB could be used as an indicator during the ablation process; its presence in the samples only negligibly influenced the intensities of the signals of most of the tested elements. Notably, high NaCl contents led to signal suppression for some of the elements. In comparison with the established sample introduction by nebulization, our developed technique abrogates the need for time-consuming sample preparation and reduces the possibility of sample contamination.

  13. A Novel Method for Fabricating Double Layers Porous Anodic Alumina in Phosphoric/Oxalic Acid Solution and Oxalic Acid Solution

    Directory of Open Access Journals (Sweden)

    Yanfang Xu

    2016-01-01

    Full Text Available A novel method for fabricating ordered double layers porous anodic alumina (DL-PAA with controllable nanopore size was presented. Highly ordered large pore layer with interpore distance of 480 nm was fabricated in phosphoric acid solution with oxalic acid addition at the potential of 195 V and the small pore layer was fabricated in oxalic acid solution at the potential from 60 to 100 V. Experimental results show that the thickness of large pore layer is linearly correlative with anodizing time, and pore diameter is linearly correlative with pore widening time. When the anodizing potential in oxalic acid solution was adjusted from 60 to 100 V, the small pore layers with continuously tunable interpore distance from 142 to 241 nm and pore density from 1.94×109 to 4.89×109 cm−2 were obtained. And the interpore distance and the pore density of small pore layers are closely correlative with the anodizing potential. The fabricated DL-PAA templates can be widely utilized for fabrication of ordered nanomaterials, such as superhydrophobic or gecko-inspired adhesive materials and metal or semiconductor nanowires.

  14. Deliquescence and efflorescence of small particles.

    Science.gov (United States)

    McGraw, Robert; Lewis, Ernie R

    2009-11-21

    We examine size-dependent deliquescence/efflorescence phase transformation for particles down to several nanometers in size. Thermodynamic properties of inorganic salt particles, coated with aqueous solution layers of varying thickness and surrounded by vapor, are analyzed. A thin layer criterion (TLC) is introduced to define a limiting deliquescence relative humidity (RH(D)) for small particles. This requires: (1) equality of chemical potentials between salt in an undissolved core, and thin adsorbed solution layer, and (2) equality of chemical potentials between water in the thin layer and vapor phase. The usual bulk deliquescence conditions are recovered in the limit of large dry particle size. Nanosize particles are found to deliquesce at relative humidity just below the RH(D) on crossing a nucleation barrier, located at a critical solution layer thickness. This barrier vanishes precisely at the RH(D) defined by the TLC. Concepts and methods from nucleation theory including the kinetic potential, self-consistent nucleation theory, nucleation theorems, and the Gibbs dividing surface provide theoretical foundation and point to unifying features of small particle deliquescence/efflorescence processes. These include common thermodynamic area constructions, useful for interpretation of small particle water uptake measurements, and a common free-energy surface, with constant RH cross sections describing deliquescence and efflorescence related through the nucleation theorem.

  15. An accurate coarse-grained model for chitosan polysaccharides in aqueous solution.

    Directory of Open Access Journals (Sweden)

    Levan Tsereteli

    Full Text Available Computational models can provide detailed information about molecular conformations and interactions in solution, which is currently inaccessible by other means in many cases. Here we describe an efficient and precise coarse-grained model for long polysaccharides in aqueous solution at different physico-chemical conditions such as pH and ionic strength. The Model is carefully constructed based on all-atom simulations of small saccharides and metadynamics sampling of the dihedral angles in the glycosidic links, which represent the most flexible degrees of freedom of the polysaccharides. The model is validated against experimental data for Chitosan molecules in solution with various degree of deacetylation, and is shown to closely reproduce the available experimental data. For long polymers, subtle differences of the free energy maps of the glycosidic links are found to significantly affect the measurable polymer properties. Therefore, for titratable monomers the free energy maps of the corresponding links are updated according to the current charge of the monomers. We then characterize the microscopic and mesoscopic structural properties of large chitosan polysaccharides in solution for a wide range of solvent pH and ionic strength, and investigate the effect of polymer length and degree and pattern of deacetylation on the polymer properties.

  16. An accurate coarse-grained model for chitosan polysaccharides in aqueous solution.

    Science.gov (United States)

    Tsereteli, Levan; Grafmüller, Andrea

    2017-01-01

    Computational models can provide detailed information about molecular conformations and interactions in solution, which is currently inaccessible by other means in many cases. Here we describe an efficient and precise coarse-grained model for long polysaccharides in aqueous solution at different physico-chemical conditions such as pH and ionic strength. The Model is carefully constructed based on all-atom simulations of small saccharides and metadynamics sampling of the dihedral angles in the glycosidic links, which represent the most flexible degrees of freedom of the polysaccharides. The model is validated against experimental data for Chitosan molecules in solution with various degree of deacetylation, and is shown to closely reproduce the available experimental data. For long polymers, subtle differences of the free energy maps of the glycosidic links are found to significantly affect the measurable polymer properties. Therefore, for titratable monomers the free energy maps of the corresponding links are updated according to the current charge of the monomers. We then characterize the microscopic and mesoscopic structural properties of large chitosan polysaccharides in solution for a wide range of solvent pH and ionic strength, and investigate the effect of polymer length and degree and pattern of deacetylation on the polymer properties.

  17. Split Hopkinson Resonant Bar Test for Sonic-Frequency Acoustic Velocity and Attenuation Measurements of Small, Isotropic Geologic Samples

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa, S.

    2011-04-01

    Mechanical properties (seismic velocities and attenuation) of geological materials are often frequency dependent, which necessitates measurements of the properties at frequencies relevant to a problem at hand. Conventional acoustic resonant bar tests allow measuring seismic properties of rocks and sediments at sonic frequencies (several kilohertz) that are close to the frequencies employed for geophysical exploration of oil and gas resources. However, the tests require a long, slender sample, which is often difficult to obtain from the deep subsurface or from weak and fractured geological formations. In this paper, an alternative measurement technique to conventional resonant bar tests is presented. This technique uses only a small, jacketed rock or sediment core sample mediating a pair of long, metal extension bars with attached seismic source and receiver - the same geometry as the split Hopkinson pressure bar test for large-strain, dynamic impact experiments. Because of the length and mass added to the sample, the resonance frequency of the entire system can be lowered significantly, compared to the sample alone. The experiment can be conducted under elevated confining pressures up to tens of MPa and temperatures above 100 C, and concurrently with x-ray CT imaging. The described Split Hopkinson Resonant Bar (SHRB) test is applied in two steps. First, extension and torsion-mode resonance frequencies and attenuation of the entire system are measured. Next, numerical inversions for the complex Young's and shear moduli of the sample are performed. One particularly important step is the correction of the inverted Young's moduli for the effect of sample-rod interfaces. Examples of the application are given for homogeneous, isotropic polymer samples and a natural rock sample.

  18. Small-scale variability in peatland pore-water biogeochemistry, Hudson Bay Lowland, Canada.

    Science.gov (United States)

    Ulanowski, T A; Branfireun, B A

    2013-06-01

    The Hudson Bay Lowland (HBL) of northern Ontario, Manitoba and Quebec, Canada is the second largest contiguous peatland complex in the world, currently containing more than half of Canada's soil carbon. Recent concerns about the ecohydrological impacts to these large northern peatlands resulting from climate change and resource extraction have catalyzed a resurgence in scientific research into this ecologically important region. However, the sheer size, heterogeneity and elaborate landscape arrangements of this ecosystem raise important questions concerning representative sampling of environmental media for chemical or physical characterization. To begin to quantify such variability, this study assessed the small-scale spatial (1m) and short temporal (21 day) variability of surface pore-water biogeochemistry (pH, dissolved organic carbon, and major ions) in a Sphagnum spp.-dominated, ombrotrophic raised bog, and a Carex spp.-dominated intermediate fen in the HBL. In general, pore-water pH and concentrations of dissolved solutes were similar to previously reported literature values from this region. However, systematic sampling revealed consistent statistically significant differences in pore-water chemistries between the bog and fen peatland types, and large within-site spatiotemporal variability. We found that microtopography in the bog was associated with consistent differences in most biogeochemical variables. Temporal changes in dissolved solute chemistry, particularly base cations (Na(+), Ca(2+) and Mg(2+)), were statistically significant in the intermediate fen, likely a result of a dynamic connection between surficial waters and mineral-rich deep groundwater. In both the bog and fen, concentrations of SO4(2-) showed considerable spatial variability, and a significant decrease in concentrations over the study period. The observed variability in peatland pore-water biogeochemistry over such small spatial and temporal scales suggests that under-sampling in

  19. Oriented Structure of Pentablock Copolymers Induced by Solution Extrusion

    Science.gov (United States)

    Harada, Tamotsu; Bates, Frank S.; Lodge, Timothy P.

    2002-03-01

    Highly oriented structure of a poly(styrene-co-butadiene) pentablock copolymer (Mw; 104,700 g/mol, weight percentage of polybutadiene blocks; 29 wt of concentrated solutions. The pentablock copolymer was dissolved into mixtures of toluene and heptane, and the polymer concentration ranged from 40 wt extrusion, the pentablock copolymer was solidified either by coagulation in methanol or by evaporation of the solvent. Interestingly, a highly oriented lamellar structure was confirmed through the small angle X-ray scattering over a specific range of heptane composition, which is a good solvent for polybutadiene, although the hexagonal cylinder morphology was identified for the melt sample. The transition from the oriented lamellar to highly oriented cylinder structure was observed by annealing the samples at temperatures above the glass transition temperature of polystyrene. Moreover, a transition from parallel to perpendicular orientation in the lamellar state was observed with an increase of the extrusion shear rate. A comparison between pentablock and triblock copolymers will be also discussed.

  20. The effect of albedo neutrons on the neutron multiplication of small plutonium oxide samples in a PNCC chamber

    CERN Document Server

    Bourva, L C A; Weaver, D R

    2002-01-01

    This paper describes how to evaluate the effect of neutrons reflected from parts of a passive neutron coincidence chamber on the neutron leakage self-multiplication, M sub L , of a fissile sample. It is shown that albedo neutrons contribute, in the case of small plutonium bearing samples, to a significant part of M sub L , and that their effect has to be taken into account in the relationship between the measured coincidence count rates and the sup 2 sup 4 sup 0 Pu effective mass of the sample. A simple one-interaction model has been used to write the balance of neutron gains and losses in the material when exposed to the re-entrant neutron flux. The energy and intensity profiles of the re-entrant flux have been parameterised using Monte Carlo MCNP sup T sup M calculations. This technique has been implemented for the On Site Laboratory neutron/gamma counter within the existing MEPL 1.0 code for the determination of the neutron leakage self-multiplication. Benchmark tests of the resulting MEPL 2.0 code with MC...