Science.gov

Sample records for resonance parameter evaluations

  1. Evaluation of the Chromium Resonance Parameters Including Resonance Parameter Covariance

    SciTech Connect

    Leal, Luiz C; Derrien, Herve; Guber, Klaus H; Arbanas, Goran; Wiarda, Dorothea

    2011-01-01

    The intent of this work is to report the results and describe the procedures utilized to evaluate the chromium isotopes' cross sections, i.e., (50)Cr, (52)Cr, (53)Cr, and (54)Cr, for criticality safety applications. The evaluations were done in the resolved resonance region using the reduced Reich-Moore R-matrix formalism. The novel aspect of this evaluation is the inclusion of new transmission and capture cross-section measurements performed at the Oak Ridge Electron Linear Accelerator (ORELA) for energies below 100 keV and the extension of the (53)Cr energy region. The resonance analysis was performed with the multilevel R-matrix code, SAMMY, which utilizes the generalized least-squares technique based on the Bayes' theory. Complete sets of resonance parameters and resonance parameter covariance matrices (RPCMs) were obtained for each of the chromium isotopes from the SAMMY analysis of the experimental database.

  2. New Resonance Parameter Evaluation of Cl Neutron Cross Sections

    SciTech Connect

    Sayer, R.O.; Guber, K.H.; Leal, L.C.; Larson, N.M.

    2005-05-24

    Better measurements and evaluations are needed for many elements where the existing evaluations or the underlying nuclear cross-section data are not sufficiently accurate for reliable calculation of criticality safety margins. Deficiencies in the existing ENDF/B-VI data evaluation for Cl led to our resonance parameter evaluation of Cl neutron cross sections in the resolved resonance region with the multilevel Reich-Moore R-matrix formalism. Our evaluation takes advantage of recent high-resolution capture and transmission measurements at the Oak Ridge Electron Linear Accelerator (ORELA) as well as older total cross-section measurements at Karlsruhe (KFK) to extend the resolved resonance energy range to 1.2 MeV with much more accurate representation of the data than previous evaluations.

  3. Evaluation of the Covariance Matrix of Estimated Resonance Parameters

    NASA Astrophysics Data System (ADS)

    Becker, B.; Capote, R.; Kopecky, S.; Massimi, C.; Schillebeeckx, P.; Sirakov, I.; Volev, K.

    2014-04-01

    In the resonance region nuclear resonance parameters are mostly obtained by a least square adjustment of a model to experimental data. Derived parameters can be mutually correlated through the adjustment procedure as well as through common experimental or model uncertainties. In this contribution we investigate four different methods to propagate the additional covariance caused by experimental or model uncertainties into the evaluation of the covariance matrix of the estimated parameters: (1) including the additional covariance into the experimental covariance matrix based on calculated or theoretical estimates of the data; (2) including the uncertainty affected parameter in the adjustment procedure; (3) evaluation of the full covariance matrix by Monte Carlo sampling of the common parameter; and (4) retroactively including the additional covariance by using the marginalization procedure of Habert et al.

  4. New evaluation of the{sup 232}Th resonance parameters in the energy range

    SciTech Connect

    Derrien, H.; Leal, L. C.; Larson, N. M.

    2006-07-01

    Neutron resonance parameters of {sup 232}Th were obtained from a Reich-Moore SAMMY analysis of high-resolution neutron transmission measurements performed at the Oak Ridge Linear Accelerator (ORELA) by Olsen et al. in 1981 and of high-resolution neutron capture measurements performed recently at the Geel Linear Accelerator (GELINA (Belgium)) by Schillebeeckx et al. and at n-TOF (CERN (Switzerland)) by Aerts et al. The ORELA data were analyzed previously by Olsen using the Breit-Wigner multilevel code SIOB, and their results were used for the ENDF/B-VI evaluation. In our new analysis of the Olsen neutron transmissions using the modern computer code SAMMY, better accuracy is obtained for the resonance parameters by including recent experimental neutron capture data in the experimental data base. The experimental data base and the method of analysis are described in the report. Neutron transmissions and capture cross sections calculated with the resonance parameters are compared to the experimental values. A description is given of the statistical properties of the resonance parameters. The new evaluation produces a decrease in the capture resonance integral, and improves the prediction of integral thermal benchmarks. (authors)

  5. Evaluation of Silicon Neutron Resonance Parameters in the Energy Range Thermal to 1800 keV

    SciTech Connect

    Derrien, H.

    2002-09-30

    The evaluation of the neutron cross sections of the three stable isotopes of silicon in the energy range thermal to 20 MeV was performed by Hetrick et al. for ENDF/B-VI (Evaluated Nuclear Data File). Resonance parameters were obtained in the energy range thermal to 1500 keV from a SAMMY analysis of the Oak Ridge National Laboratory experimental neutron transmission data. A new measurement of the capture cross section of natural silicon in the energy range 1 to 700 keV has recently been performed at the Oak Ridge Electron Linear Accelerator. Results of this measurement were used in a SAMMY reevaluation of the resonance parameters, allowing determination of the capture width of a large number of resonances. The experimental data base is described; properties of the resonance parameters are given. For the first time the direct neutron capture component has been taken into account from the calculation by Rauscher et al. in the energy range from thermal to 1 MeV. Results of benchmark calculations are also given. The new evaluation is available in the ENDF/B-VI format.

  6. Evaluation of silicon neutron resonance parameters in the thermal to 1800 keV energy range.

    PubMed

    Derrien, H; Leal, L C; Guber, K H; Larson, N M

    2005-01-01

    Because silicon is a major constituent of concrete and soil, neutron and gamma ray information on silicon is important for reactor shielding and criticality safety calculations. Therefore, much effort was put into the ENDF/B-VI evaluation for the three stable isotopes of silicon. The neutron capture cross section of natural silicon was recently measured at the Oak Ridge Electron Linear Accelerator (ORELA) in the energy range 1-700 keV. Using the ENDF/B-VI evaluation for initial values, a new evaluation of the resonance parameters was performed by adding the results of the ORELA capture measurements to the experimental database. The computer code SAMMY was used for the analysis of the experimental data; the new version of SAMMY allows accurate calculations of the self-shielding and multiple scattering effects in the capture measurements. The accuracy of the radiative capture widths of the resonances was improved by this analysis. Accurate values of the s-, p- and d-wave neutron strength functions were also obtained. Although the resonance capture component of the present evaluation is 2-3 times smaller than that in ENDF/B-VI, the total capture cross section is much larger, at least for energies >250 keV, because the direct capture component contributes values of the same order of magnitude as the resonance component. The direct component was not taken into account in the ENDF/B-VI evaluation and was calculated for the first time in the present evaluation.

  7. Evaluation of 238U Resonance Parameters from 0 to 20 keV

    SciTech Connect

    Derrien, H.; Leal, L.C.; Larson, N.; Courcelle, A.; Santamarina, A.

    2005-05-24

    The neutron resonance parameters of 238U were obtained in the energy range 0 to 20 keV from a sequential SAMMY analysis of the most recent high-resolution neutron transmission and neutron capture cross-section measurements. Special care was taken in the analysis of the lowest s-wave resonances leading to resonance parameters slightly different from those of ENDF/B-VI (Moxon-Sowerby resonance parameters). The resolved-resonance range was extended to 20 keV, taking advantage of the high-resolution neutron transmission data of Harvey and neutron capture data of Macklin et al. Preliminary integral tests were performed with the new resonance parameters; thermal low-enriched benchmark calculations show an improvement of the keff prediction, mainly due to a 1.5% decrease of the capture cross section at 0.0253 eV and about a 0.4% decrease of the effective shielded resonance capture integral.

  8. Some highlights in the evaluations of the thermal cross sections and resonance parameters of the actinides

    SciTech Connect

    Mughabghab, S.F.; Divadeenam, M.

    1981-01-01

    The resonance parameters and thermal cross sections of /sup 235/ /sup 238/U and /sup 239/ /sup 240/ /sup 241/ /sup 242/Pu are reevaluated by considering the measurements carried out since 1973. Capture, scattering, fission cross sections as well as resonance integrals are calculated from the parameters and are compared with experimental values with the objective of achieving consistency between calculations and measurements. The Dyson-Metha ..delta../sub 3/ statistical analysis was applied in order to calculate average level spacings. Calculations of average radiative widths based on systematics are carried out and are compared with experimental values as well as with Moore's and Lynn's estimates.

  9. Fascicular Ratio: A New Parameter to Evaluate Peripheral Nerve Pathology on Magnetic Resonance Imaging

    PubMed Central

    Tagliafico, Alberto S.; Tagliafico, Giulio

    2014-01-01

    Abstract The objective of the study was to define and quantitatively evaluate the fascicular ratio (FR) on magnetic resonance imaging (MRI) in patients with peripheral neuropathies compared with healthy controls. Forty control subjects (20 women, 20 men; age, 44.6 ± 13.4 years) and 40 patients with peripheral neuropathy (22 women, 18 men; age, 50.3 ± 10.2 years) were examined with a standard 3T MRI protocol. With customized software (with semiautomatic and automatic interface), the hypointense and hyperintense areas of the peripheral nerves corresponding to fascicular and nonfascicular tissue were examined on T1-weighted sequences. The ratio of fascicular pixels to total pixels was called FR. Correlation with FR calculated on high-resolution ultrasound was performed. The statistical analysis included the Mann–Whitney U test of controls versus patients, the receiver operating characteristic (ROC) analysis, and the subgroup analysis of patients according to etiologies of neuropathy. Intraobserver and interobserver agreement was calculated based on the evaluation made by 3 readers. Finally, a complete automatic evaluation was performed. On MRI, FRs were significantly increased in patients compared with controls (FR, 76.7 ± 15.1 vs 56 ± 12.3; P < 0.0001 for the semiautomatic interface; and FR 66.3 ± 17.5 vs 47.8 ± 18.4; P < 0.0001 for the automatic interface). The increase in FR was caused mainly by an increase in the hypointense part of the nerve. This observation was valid for all causes of neuropathies. ROC analysis found an area under the curve of 0.75 (95% confidence interval, 0.44–0.81) for FR to discriminate neuropathy from control. The correlation coefficient between MRI and ultrasound was significant (r = 0.49; 95% confidence interval for r, 0.21–0.70; P = 0.012). With the semiautomated evaluation, the mean intraobserver agreement was good (K = 0.86). The interobserver agreements were also good (reader 1

  10. New Neutron Cross-Section Measurements from ORELA and New Resonance Parameter Evaluations

    SciTech Connect

    Guber, Klaus H; Koehler, Paul; Wiarda, Dorothea; Harvey, John A; Valentine, Timothy E; Sayer, Royce O; Leal, Luiz C; Larson, Nancy M; Bigelow, Tim S

    2008-01-01

    A series of new measurements has been undertaken in response to deficiencies identified in nuclear data libraries of crucial importance to the Nuclear Criticality Safety Program. New data and evaluations, including covariances, are required for several materials found in mixtures with uranium. For this purpose we performed neutron capture and total cross-section measurements on natural potassium, {sup 41}K, and manganese.

  11. Resonance Parameter Adjustment Based on Integral Experiments

    SciTech Connect

    Sobes, Vladimir; Leal, Luiz; Arbanas, Goran; Forget, Benoit

    2016-06-02

    Our project seeks to allow coupling of differential and integral data evaluation in a continuous-energy framework and to use the generalized linear least-squares (GLLS) methodology in the TSURFER module of the SCALE code package to update the parameters of a resolved resonance region evaluation. We recognize that the GLLS methodology in TSURFER is identical to the mathematical description of a Bayesian update in SAMMY, the SAMINT code was created to use the mathematical machinery of SAMMY to update resolved resonance parameters based on integral data. Traditionally, SAMMY used differential experimental data to adjust nuclear data parameters. Integral experimental data, such as in the International Criticality Safety Benchmark Experiments Project, remain a tool for validation of completed nuclear data evaluations. SAMINT extracts information from integral benchmarks to aid the nuclear data evaluation process. Later, integral data can be used to resolve any remaining ambiguity between differential data sets, highlight troublesome energy regions, determine key nuclear data parameters for integral benchmark calculations, and improve the nuclear data covariance matrix evaluation. Moreover, SAMINT is not intended to bias nuclear data toward specific integral experiments but should be used to supplement the evaluation of differential experimental data. Using GLLS ensures proper weight is given to the differential data.

  12. Resonance Parameter Adjustment Based on Integral Experiments

    DOE PAGES

    Sobes, Vladimir; Leal, Luiz; Arbanas, Goran; ...

    2016-06-02

    Our project seeks to allow coupling of differential and integral data evaluation in a continuous-energy framework and to use the generalized linear least-squares (GLLS) methodology in the TSURFER module of the SCALE code package to update the parameters of a resolved resonance region evaluation. We recognize that the GLLS methodology in TSURFER is identical to the mathematical description of a Bayesian update in SAMMY, the SAMINT code was created to use the mathematical machinery of SAMMY to update resolved resonance parameters based on integral data. Traditionally, SAMMY used differential experimental data to adjust nuclear data parameters. Integral experimental data, suchmore » as in the International Criticality Safety Benchmark Experiments Project, remain a tool for validation of completed nuclear data evaluations. SAMINT extracts information from integral benchmarks to aid the nuclear data evaluation process. Later, integral data can be used to resolve any remaining ambiguity between differential data sets, highlight troublesome energy regions, determine key nuclear data parameters for integral benchmark calculations, and improve the nuclear data covariance matrix evaluation. Moreover, SAMINT is not intended to bias nuclear data toward specific integral experiments but should be used to supplement the evaluation of differential experimental data. Using GLLS ensures proper weight is given to the differential data.« less

  13. Neutron Resonance Parameters for Cm-242 (Curium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Volume 24 `Neutron Resonance Parameters' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms'. It provides the neutron resonance parameters for the isotope Cm-242 (Curium).

  14. Neutron Resonance Parameters for Np-237 (Neptunium)

    NASA Astrophysics Data System (ADS)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Volume 24 `Neutron Resonance Parameters' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms'. It provides the neutron resonance parameters for the isotope Np-237 (Neptunium).

  15. Integral data analysis for resonance parameters determination

    SciTech Connect

    Larson, N.M.; Leal, L.C.; Derrien, H.

    1997-09-01

    Neutron time-of-flight experiments have long been used to determine resonance parameters. Those resonance parameters have then been used in calculations of integral quantities such as Maxwellian averages or resonance integrals, and results of those calculations in turn have been used as a criterion for acceptability of the resonance analysis. However, the calculations were inadequate because covariances on the parameter values were not included in the calculations. In this report an effort to correct for that deficiency is documented: (1) the R-matrix analysis code SAMMY has been modified to include integral quantities of importance, (2) directly within the resonance parameter analysis, and (3) to determine the best fit to both differential (microscopic) and integral (macroscopic) data simultaneously. This modification was implemented because it is expected to have an impact on the intermediate-energy range that is important for criticality safety applications.

  16. Resonance parameter analysis with SAMMY

    SciTech Connect

    Larson, N.M.; Perey, F.G.

    1988-01-01

    The multilevel R-matrix computer code SAMMY has evolved over the past decade to become an important analysis tool for neutron data. SAMMY uses the Reich-Moore approximation to the multilevel R-matrix and includes an optional logarithmic parameterization of the external R-function. Doppler broadening is simulated either by numerical integration using the Gaussian approximation to the free gas model or by a more rigorous solution of the partial differential equation equivalent to the exact free gas model. Resolution broadening of cross sections and derivatives also has new options that more accurately represent the experimental situation. SAMMY treats constant normalization and some types of backgrounds directly and treats other normalizations and/or backgrounds with the introduction of user-generated partial derivatives. The code uses Bayes' method as an efficient alternative to least squares for fitting experimental data. SAMMY allows virtually any parameter to be varied and outputs values, uncertainties, and covariance matrix for all varied parameters. Versions of SAMMY exist for VAX, FPS, and IBM computers.

  17. Influence of resonance parameters' correlations on the resonance integral uncertainty; 55Mn case

    NASA Astrophysics Data System (ADS)

    Žerovnik, Gašper; Trkov, Andrej; Capote, Roberto; Rochman, Dimitri

    2011-03-01

    For nuclides with a large number of resonances the covariance matrix of resonance parameters can become very large and expensive to process in terms of the computation time. By converting covariance matrix of resonance parameters into covariance matrices of background cross-section in a more or less coarse group structure a considerable amount of computer time and memory can be saved. The question is how important is the information that is discarded in the process. First, the uncertainty of the 55Mn resonance integral was estimated in narrow resonance approximation for different levels of self-shielding using Bondarenko method by random sampling of resonance parameters according to their covariance matrices from two different 55Mn evaluations: one from Nuclear Research and Consultancy Group NRG (with large uncertainties but no correlations between resonances), the other from Oak Ridge National Laboratory (with smaller uncertainties but full covariance matrix). We have found out that if all (or at least significant part of the) resonance parameters are correlated, the resonance integral uncertainty greatly depends on the level of self-shielding. Second, it was shown that the commonly used 640-group SAND-II representation cannot describe the increase of the resonance integral uncertainty. A much finer energy mesh for the background covariance matrix would have to be used to take the resonance structure into account explicitly, but then the objective of a more compact data representation is lost.

  18. Rho resonance parameters from lattice QCD

    SciTech Connect

    Guo, Dehua; Alexandru, Andrei; Molina, Raquel; Döring, Michael

    2016-08-01

    We perform a high-precision calculation of the phase shifts for $\\pi$-$\\pi$ scattering in the I = 1, J = 1 channel in the elastic region using elongated lattices with two mass-degenerate quark favors ($N_f = 2$). We extract the $\\rho$ resonance parameters using a Breit-Wigner fit at two different quark masses, corresponding to $m_{\\pi} = 226$MeV and $m_{\\pi} = 315$MeV, and perform an extrapolation to the physical point. The extrapolation is based on a unitarized chiral perturbation theory model that describes well the phase-shifts around the resonance for both quark masses. We find that the extrapolated value, $m_{\\rho} = 720(1)(15)$MeV, is significantly lower that the physical rho mass and we argue that this shift could be due to the absence of the strange quark in our calculation.

  19. Resonance parameter measurements and analysis of gadolinium

    SciTech Connect

    Leinweber, G.; Barry, D. P.; Trbovich, M. J.; Burke, J. A.; Drindak, N. J.; Knox, H. D.; Ballad, R. V.; Block, R. C.; Danon, Y.; Severnyak, L. I.

    2006-07-01

    The purpose of the present work is to measure the neutron cross sections of gadolinium accurately. Gd has the highest thermal absorption cross section of any natural element. Therefore it is an important element for thermal reactor applications Neutron capture and transmission measurements were performed by the time-of-flight technique at the Rensselaer Polytechnic Inst. (RPI) LINAC facility using metallic and liquid Gd samples. The liquid samples were isotopically-enriched in either {sup 155}Gd or {sup 157}Gd. The capture measurements were made at the 25-m flight station with a sodium iodide detector, and the transmission measurements were performed at 15- and 25-m flight stations with {sup 6}Li glass scintillation detectors. The multilevel R-matrix Bayesian code SAMMY was used to extract resonance parameters. The results of the thermal region analysis are significant. Resonance parameters for the low energy doublet, at 0.025 and 0.032 eV, are presented. The thermal (2200 m/s) capture cross section of {sup 157}Gd has been measured to be 11% smaller than that calculated from ENDF/B-VI updated through release 8. Thermal capture cross sections and capture resonance integrals for each isotope as well as elemental gadolinium are presented. In the epithermal region, natural metal samples were measured in capture and transmission. Neutron interaction data up to 300 eV have been analyzed. Substantial improvement to the understanding of gadolinium cross sections is presented, particularly above 180 eV where the ENDF resolved region for {sup 155}Gd ends. (authors)

  20. ORNL Resonance Evaluation for ENDF/B-VII.1

    SciTech Connect

    Leal, Luiz C; Guber, Klaus H; Wiarda, Dorothea; Arbanas, Goran; Dunn, Michael E

    2012-01-01

    Cross-section evaluations in the resonance region are performed at Oak Ridge National Laboratory (ORNL) with the computer code SAMMY based on formalisms derived from the R-matrix theory. Resonance parameters (RPs) obtained in the evaluation, combined with resonance formalism, replicate a regression of the experimental data. The RPs are also used to generate cross-section data for neutron transport calculations in analyses of nuclear reactor design and nuclear criticality safety. In addition to generating RPs, the evaluation also generates the resonance parameter covariance (RPC) data. Several ORNL resonance evaluations, including RPs and RPCs, were incorporated in the recently released US-evaluated nuclear data library, ENDF/B-VII.1. A brief summary of the RPs and RPCs evaluated at ORNL is given.

  1. Single-level resonance parameters fit nuclear cross-sections

    NASA Technical Reports Server (NTRS)

    Drawbaugh, D. W.; Gibson, G.; Miller, M.; Page, S. L.

    1970-01-01

    Least squares analyses of experimental differential cross-section data for the U-235 nucleus have yielded single level Breit-Wigner resonance parameters that fit, simultaneously, three nuclear cross sections of capture, fission, and total.

  2. 239Pu Resonance Evaluation for Thermal Benchmark System Calculations

    SciTech Connect

    Leal, Luiz C; Noguere, G; De Saint Jean, C; Kahler, A.

    2013-01-01

    Analyses of thermal plutonium solution critical benchmark systems have indicated a deciency in the 239Pu resonance evaluation. To investigate possible solutions to this issue, the Organisation for Economic Co-operation and Development (OECD) Nuclear Energy Agency (NEA) Working Party for Evaluation Cooperation (WPEC) established Subgroup 34 to focus on the reevaluation of the 239Pu resolved resonance parameters. In addition, the impacts of the prompt neutron multiplication (nubar) and the prompt neutron ssion spectrum (PFNS) have been investigated. The objective of this paper is to present the results of the 239Pu resolved resonance evaluation eort.

  3. 239Pu Resonance Evaluation for Thermal Benchmark System Calculations

    NASA Astrophysics Data System (ADS)

    Leal, L. C.; Noguere, G.; de Saint Jean, C.; Kahler, A. C.

    2014-04-01

    Analyses of thermal plutonium solution critical benchmark systems have indicated a deficiency in the 239Pu resonance evaluation. To investigate possible solutions to this issue, the Organisation for Economic Co-operation and Development (OECD) Nuclear Energy Agency (NEA) Working Party for Evaluation Cooperation (WPEC) established Subgroup 34 to focus on the reevaluation of the 239Pu resolved resonance parameters. In addition, the impacts of the prompt neutron multiplicity (νbar) and the prompt neutron fission spectrum (PFNS) have been investigated. The objective of this paper is to present the results of the 239Pu resolved resonance evaluation effort.

  4. On random sampling of correlated resonance parameters with large uncertainties

    NASA Astrophysics Data System (ADS)

    Žerovnik, Gašper; Capote, Roberto; Trkov, Andrej

    2013-09-01

    Three different methods for multivariate random sampling of correlated resonance parameters are proposed: the diagonalization method, the Metropolis method, and the correlated sampling method. For small relative uncertainties (typical for s-wave resonances) and weak correlations all methods are equivalent. Differences arise under difficult conditions: large relative uncertainties of inherently positive parameters (typical for widths of higher-l-wave resonances) and/or strong correlations between a large number of parameters. The methods are tested on realistic examples; advantages and disadvantages of each method are pointed out. The correlated sampling method is the only method which produces consistent samples under any conditions. In the field of reactor physics, these methods are mostly used for the sampling of nuclear data, however, they may be used for any data with given uncertainties and correlations.

  5. Neutron Resonance Parameters and Covariance Matrix of 239Pu

    SciTech Connect

    Derrien, Herve; Leal, Luiz C; Larson, Nancy M

    2008-08-01

    In order to obtain the resonance parameters in a single energy range and the corresponding covariance matrix, a reevaluation of 239Pu was performed with the code SAMMY. The most recent experimental data were analyzed or reanalyzed in the energy range thermal to 2.5 keV. The normalization of the fission cross section data was reconsidered by taking into account the most recent measurements of Weston et al. and Wagemans et al. A full resonance parameter covariance matrix was generated. The method used to obtain realistic uncertainties on the average cross section calculated by SAMMY or other processing codes was examined.

  6. 95Mo nuclear magnetic resonance parameters of molybdenum hexacarbonyl from density functional theory: appraisal of computational and geometrical parameters.

    PubMed

    Cuny, Jérôme; Sykina, Kateryna; Fontaine, Bruno; Le Pollès, Laurent; Pickard, Chris J; Gautier, Régis

    2011-11-21

    Solid-state (95)Mo nuclear magnetic resonance (NMR) properties of molybdenum hexacarbonyl have been computed using density functional theory (DFT) based methods. Both quadrupolar coupling and chemical shift parameters were evaluated and compared with parameters of high precision determined using single-crystal (95)Mo NMR experiments. Within a molecular approach, the effects of major computational parameters, i.e. basis set, exchange-correlation functional, treatment of relativity, have been evaluated. Except for the isotropic parameter of both chemical shift and chemical shielding, computed NMR parameters are more sensitive to geometrical variations than computational details. Relativistic effects do not play a crucial part in the calculations of such parameters for the 4d transition metal, in particular isotropic chemical shift. Periodic DFT calculations were tackled to measure the influence of neighbouring molecules on the crystal structure. These effects have to be taken into account to compute accurate solid-state (95)Mo NMR parameters even for such an inorganic molecular compound.

  7. Evaluation of Neutron Resonance Cross Section Data at GELINA

    NASA Astrophysics Data System (ADS)

    Schillebeeckx, P.; Becker, B.; Capote, R.; Emiliani, F.; Guber, K.; Heyse, J.; Kauwenberghs, K.; Kopecky, S.; Lampoudis, C.; Massimi, C.; Mondelaers, W.; Moxon, M.; Noguere, G.; Plompen, A. J. M.; Pronyaev, V.; Siegler, P.; Sirakov, I.; Trkov, A.; Volev, K.; Zerovnik, G.

    2014-05-01

    Over the last decade, the EC-JRC-IRMM, in collaboration with other institutes such as INRNE Sofia (BG), INFN Bologna (IT), ORNL (USA), CEA Cadarache (FR) and CEA Saclay (FR), has made an intense effort to improve the quality of neutron-induced cross section data in the resonance region. These improvements relate to both the infrastructure of the facility and the measurement setup, and the data reduction and analysis procedures. As a result total and reaction cross section data in the resonance region with uncertainties better than 0.5 % and 2 %, respectively, can be produced together with evaluated data files for both the resolved and unresolved resonance region. The methodology to produce full ENDF compatible files, including covariances, is illustrated by the production of resolved resonance parameter files for 241Am, Cd and W and an evaluation for 197Au in the unresolved resonance region.

  8. Parameter measurement of synchronous reluctance motor using LC resonance

    NASA Astrophysics Data System (ADS)

    Ahn, Joonseon; Kim, Ki-Chan; Lee, Ju

    2006-04-01

    The motor characterizing parameters are most important factors to drive precisely, effectively, and robustly. Especially, the exact knowledge of synchronous inductance is necessary to control the torque precisely in synchronous reluctance motor (SynRM). Therefore many works have been done for the exact measurement of motor parameters. In this paper, we propose the simple method of measuring the motor parameters, especially measuring the synchronous inductance of SynRM, which can overcome the demerits of conventional methods and measure the exact values. The proposed method uses the resonance phenomenon between the phase inductance and capacitors externally connected.

  9. Comparison of Resonance Parameter Covariance Generation using CONRAD and SAMMY Computer Codes

    SciTech Connect

    Leal, Luiz C; De Saint Jean, C; Noguere, G

    2010-01-01

    Cross section evaluations in the resolved resonance region are based on formalisms derived from the R-matrix theory. As a result, the evaluations provide a set of resonance parameters that can be used to reproduce the experimental data reasonably well. The evaluated nuclear data are used in neutron transport calculations for the analysis and design of nuclear reactor systems, nuclear criticality safety analyses, etc. To achieve the desired accuracy on the nuclear system calculations, the questions frequently asked are how well the nuclear data are known and how the uncertainty in the nuclear data can be propagated into the final nuclear system results. There have been ongoing efforts at several research centers for generating data uncertainties in the resonance and high-energy regions. The biggest issue in relation to the covariance data is how good the calculated uncertainties are or whether the calculated uncertainties are in agreement with realistic uncertainties derived from an experimental nuclear system or nuclear benchmark. In this work an attempt is made to use two distinct and independently developed computer codes, CONRAD and SAMMY, to evaluate and generate covariance data in the resonance region. The verification study has been performed in support of the U.S. Nuclear Criticality Safety program (NCSP) as the NCSP is working to provide improved nuclear data files to support criticality safety analyses. The objective is to check the procedures and the methodologies used in the resonance region for covariance generation. The studies have been carried out using the 48Ti resolved resonance parameters.

  10. Parameters optimization for magnetic resonance coupling wireless power transmission.

    PubMed

    Li, Changsheng; Zhang, He; Jiang, Xiaohua

    2014-01-01

    Taking maximum power transmission and power stable transmission as research objectives, optimal design for the wireless power transmission system based on magnetic resonance coupling is carried out in this paper. Firstly, based on the mutual coupling model, mathematical expressions of optimal coupling coefficients for the maximum power transmission target are deduced. Whereafter, methods of enhancing power transmission stability based on parameters optimal design are investigated. It is found that the sensitivity of the load power to the transmission parameters can be reduced and the power transmission stability can be enhanced by improving the system resonance frequency or coupling coefficient between the driving/pick-up coil and the transmission/receiving coil. Experiment results are well conformed to the theoretical analysis conclusions.

  11. Giant dipole resonance parameters with uncertainties from photonuclear cross sections

    NASA Astrophysics Data System (ADS)

    Plujko, V. A.; Capote, R.; Gorbachenko, O. M.

    2011-09-01

    Updated values and corresponding uncertainties of isovector giant dipole resonance (IVGDR or GDR) model parameters are presented that are obtained by the least-squares fitting of theoretical photoabsorption cross sections to experimental data. The theoretical photoabsorption cross section is taken as a sum of the components corresponding to excitation of the GDR and quasideuteron contribution to the experimental photoabsorption cross section. The present compilation covers experimental data as of January 2010.

  12. Some principles in choosing parameters of magnetic resonance tomographs

    NASA Astrophysics Data System (ADS)

    Volobuev, A. N.

    2017-01-01

    The problem of amplifying the signal that ensures the visualization of internal organs in the magnetic resonance tomograph due to the optimal selection of some of its parameters has been considered. The operating principle of the tomograph has been analyzed. The relation between the angle of the magnetic moment precession in hydrogen nuclei in an organism, the frequency of the ac magnetic field exciting this precession, and the constant magnetic field used has been determined using quantum-mechanical concepts. This relation makes it possible to determine the optimal parameters for tomograph operation.

  13. Evaluation and Treatment of Resonance Disorders.

    ERIC Educational Resources Information Center

    Kummer, Ann W.; Lee, Linda

    1996-01-01

    Resonance disorders can have a variety of causes but the appropriate evaluation includes a speech pathology evaluation and may require a videofluoroscopic speech study or nasopharyngoscopy assessment. Treatment may include surgery or the use of prosthetic devices, and usually speech therapy. An interdisciplinary approach is best. (Author/DB)

  14. Reevaluation and Validation of the {sup 241}Pu Resonance Parameters in the Energy Range Thermal to 20 eV

    SciTech Connect

    Derrien, H.; Leal, L.C.; Courcelle, A.; Santamarina, A.

    2005-05-15

    A new SAMMY analysis of the {sup 241}Pu resonance parameters from thermal to 20 eV is presented. This evaluation takes into account the trends given by integral experiments [post-irradiation experiments performed in French pressurized water reactors (PWRs)]. Compared to the previous evaluations performed by Derrien and de Saussure, the capture cross section increases especially in the 0.26-eV resonance. It is shown that the new resonance parameters proposed in this work improve the prediction of the {sup 242}Pu buildup in a PWR, which was significantly underestimated with the previous evaluations.

  15. Statistical parameters for gloss evaluation

    SciTech Connect

    Peiponen, Kai-Erik; Juuti, Mikko

    2006-02-13

    The measurement of minute changes in local gloss has not been presented in international standards due to a lack of suitable glossmeters. The development of a diffractive-element-based glossmeter (DOG) made it possible to detect local variation of gloss from planar and complex-shaped surfaces. Hence, a demand for proper statistical gloss parameters for classifying surface quality by gloss, similar to the standardized surface roughness classification, has become necessary. In this letter, we define statistical gloss parameters and utilize them as an example in the characterization of gloss from metal surface roughness standards by the DOG.

  16. Resonance Evaluation of 48Ti Including Covariance for Criticality Safety Applications

    SciTech Connect

    Leal, Luiz C; Guber, Klaus H; Arbanas, Goran; Wiarda, Dorothea; Koehler, Paul Edward; Kahler, A.

    2011-01-01

    In this work we report the methodology and the results of an evaluation carried out for 48Ti in the resolved resonance region for applications in criticality safety calculations. The evaluation was performed using the computer code SAMMY with the reduced R-matrix Reich-Moore formalism. The Bayes scheme was utilized for fitting the experimental data. New transmission and capture data were essential in the evaluation process. A complete set of resonance parameters was obtained in the energy region from thermal to 400 keV. In addition to the resonance parameters, a resonance parameter covariance matrix was also obtained. The impact of the new resonance parameter evaluation in benchmark calculations, as well as the uncertainty, was verified.

  17. On the Methodology to Calculate the Covariance of Estimated Resonance Parameters

    SciTech Connect

    Becker, B.; Kopecky, S.; Schillebeeckx, P.

    2015-01-15

    Principles to determine resonance parameters and their covariance from experimental data are discussed. Different methods to propagate the covariance of experimental parameters are compared. A full Bayesian statistical analysis reveals that the level to which the initial uncertainty of the experimental parameters propagates, strongly depends on the experimental conditions. For high precision data the initial uncertainties of experimental parameters, like a normalization factor, has almost no impact on the covariance of the parameters in case of thick sample measurements and conventional uncertainty propagation or full Bayesian analysis. The covariances derived from a full Bayesian analysis and least-squares fit are derived under the condition that the model describing the experimental observables is perfect. When the quality of the model can not be verified a more conservative method based on a renormalization of the covariance matrix is recommended to propagate fully the uncertainty of experimental systematic effects. Finally, neutron resonance transmission analysis is proposed as an accurate method to validate evaluated data libraries in the resolved resonance region.

  18. Resonance Parameters of the Rho-Meson from Lattice QCD

    SciTech Connect

    Xu Feng, Karl Jansen, Dru Renner

    2011-05-01

    We perform a non-perturbative lattice calculation of the P-wave pion-pion scattering phase in the rho-meson decay channel using two flavors of maximally twisted mass fermions at pion masses ranging from 480 MeV to 290 MeV. Making use of finite-size methods, we evaluate the pion-pion scattering phase in the center-of-mass frame and two moving frames. Applying an effective range formula, we find a good description of our results for the scattering phase as a function of the energy covering the resonance region. This allows us to extract the rho-meson mass and decay width and to study their quark mass dependence.

  19. Compound piezoelectric cylindrical resonators as sensors of the rheological parameters of viscoelastic media.

    PubMed

    Kiełczyński, Piotr; Szalewski, Marek

    2007-06-01

    The electro-elastic behavior of a viscoelastically loaded layered cylindrical resonator (sensor) comprising two coupled hollow cylinders is presented. The inner cylinder is a piezoelectric ceramic tube. The outer cylinder is a non-piezoelectric (passive) metallic cylinder. An analytical formula for the electrical admittance of a compound layered cylindrical resonator loaded with a viscoelastic liquid is established. Admittance (conductance) diagrams were obtained using a continuum electromechanical model. The established analytical formulas enable the determination of the influence of the liquid viscosity, material, and geometrical parameters of a compound cylindrical resonator on the response characteristics of the compound sensor. In the paper, the sensor implications resulting from the performed analysis are described. Moreover, the algorithm of the method developed by the authors to evaluate the rheological parameters of a viscoelastic liquid is presented. Good agreement between the theoretical results and experimental data is shown. The analysis presented in this paper can be utilized for the design and construction of cylindrical piezoelectric viscosity sensors, annular accelerometers, filters, transducers, and multilayer resonators.

  20. Resonance in a weakly nonlinear system with slowly varying parameters

    NASA Astrophysics Data System (ADS)

    Kevorkian, J.

    1980-02-01

    Multiple-variable expansion procedures appropriate for nonlinear systems in resonance are surveyed by the use of the model of two coupled weakly nonlinear oscillators with either constant or slowly varying frequencies. In the autonomous problem it is shown that an n-variable expansion (where n depends on the order of accuracy desired) yields uniformly valid results. The problem of passage through resonance for the nonautonomous problem is also considered and the solution is described by constructing a sequence of three expansions. The solution before resonance is developed as a generalized multiple-variable expansion and is matched with an inner expansion valid during resonance. This latter is then matched with a postresonance solution and determines it completely. Numerical integrations are used to substantiate the theoretical results. The dominant effect of passage through resonance is shown to be the excitation of a higher-order oscillation beyond resonance. Contrary to the claim in a recent work, the total action of the system does not remain constant if one accounts for the leading perturbation terms in the postresonance solution. Instead, the total action goes from one constant value to another.

  1. R-MATRIX RESONANCE ANALYSIS AND STATISTICAL PROPERTIES OF THE RESONANCE PARAMETERS OF 233U IN THE NEUTRON ENERGY RANGE FROM THERMAL TO 600 eV

    SciTech Connect

    Leal, L.C.

    2001-02-27

    The R-matrix resonance analysis of experimental neutron transmission and cross sections of {sup 233}U, with the Reich-Moore Bayesian code SAMMY, was extended up to the neutron energy of 600 eV by taking advantage of new high resolution neutron transmission and fission cross section measurements performed at the Oak Ridge Electron Linear Accelerator (ORELA). The experimental data base is described. In addition to the microscopic data (time-of-flight measurements of transmission and cross sections), some experimental and evaluated integral quantities were included in the data base. Tabulated and graphical comparisons between the experimental data and the SAMMY calculated cross sections are given. The ability of the calculated cross sections to reproduce the effective multiplication factors k{sub eff} for various thermal, intermediate, and fast systems was tested. The statistical properties of the resonance parameters were examined and recommended values of the average s-wave resonance parameters are given.

  2. Evaluation of Tungsten Neutron Cross Sections in the Resolved Resonance Regions

    SciTech Connect

    Pigni, Marco T; Leal, Luiz C; Dunn, Michael E; Guber, Klaus H; Emiliani, F.; Kopecky, S.; Lampoudis, C.; Schillebeeckx, P.; Siegler, P.

    2014-01-01

    We generated a preliminary set of resonance parameters for 182-184,186W in the neutron energy range of thermal up to several keV. The evaluation methodology uses the Reich-Moore approximation to t, with the R-matrix code SAMMY, the high-resolution measurements performed in 2010 and 2012 at the GEel LINear Accelerator (GELINA) facility. Particularly for 183W, the transmission data and the capture cross sections calculated with the set of resonance parameters are compared with the experimental values, and some of the average properties of the resonance parameters are discussed. In the analyzed energy range, this work almost doubles the existing resolved resonance evaluations in the ENDF/B-VII.1 library. The analysis of the performance of the calculated cross sections based on criticality benchmarks is still in progress and it is only briefly discussed.

  3. Effects of relevant parameters on the bandgaps of acoustic metamaterials with multi-resonators

    NASA Astrophysics Data System (ADS)

    Zhou, Xiaoqin; Wang, Jun; Wang, Rongqi; Lin, Jieqiong

    2016-04-01

    Locally resonant acoustic metamaterials with multi-resonators are generally regarded as a fine trend for managing the bandgaps, the different effects of relevant structural parameters on the bandgaps, which will be numerically investigated in this paper. A two-step homogenization method is extended to achieve the effective mass of multi-resonators metamaterial in the lattice system. As comparison, the dispersive wave propagation in lattice system and continuum model is studied. Then, the different effects of relevant parameters on the center frequencies and bandwidth of bandgaps are perfectly revealed, and the steady-state responses in the continuum models with purposed relevant parameters are additionally clarified. The related results can well confirm that the bandgaps exist around the undamped natural frequencies of internal resonators, and also their bandwidth can be efficiently controlled with the ensured center frequencies. Moreover, the design of purposed multi-resonators acoustic metamaterial in vibration control is presented and discussed by an example.

  4. {sup 12}O resonant structure evaluated by the two-proton emission process

    SciTech Connect

    Leite, T. N.; Teruya, N.; Dimarco, A.; Duarte, S. B.; Tavares, O. A. P.

    2009-07-15

    The characteristics of the {sup 12}O resonant ground state are investigated through the analysis of the experimental data for the two-proton decay process. The sequential and simultaneous two-proton emission decay modes have been considered in a statistical calculation of the decay energy distribution. The resonant structures of {sup 11}N have been employed as intermediate states for the sequential mode, having their parameters determined by considering the structure of single particle resonance in quantum scattering problem. The width of the {sup 12}O resonant ground state has been extracted from a best fit to the experimental data. The contributions from the different channels to the decay energy distribution have been evaluated, and width and peak location parameters of the {sup 12}O resonant ground state are compared with results of other works for the sequential and simultaneous two-proton decay modes.

  5. SAMDIST: A Computer Code for Calculating Statistical Distributions for R-Matrix Resonance Parameters

    SciTech Connect

    Leal, L.C.

    1995-01-01

    The: SAMDIST computer code has been developed to calculate distribution of resonance parameters of the Reich-Moore R-matrix type. The program assumes the parameters are in the format compatible with that of the multilevel R-matrix code SAMMY. SAMDIST calculates the energy-level spacing distribution, the resonance width distribution, and the long-range correlation of the energy levels. Results of these calculations are presented in both graphic and tabular forms.

  6. Chronic liver disease: evaluation by magnetic resonance

    SciTech Connect

    Stark, D.D.; Goldberg, H.I.; Moss, A.A.; Bass, N.M.

    1984-01-01

    Magnetic resonance (MR) imaging distinguished hepatitis from fatty liver and cirrhosis in a woman with a history of alcohol abuse. Anatomic and physiologic manifestations of portal hypertension were also demonstrated by MR.

  7. Vibroacoustic test plan evaluation: Parameter variation study

    NASA Technical Reports Server (NTRS)

    Stahle, C. V.; Gongloef, H. R.

    1976-01-01

    Statistical decision models are shown to provide a viable method of evaluating the cost effectiveness of alternate vibroacoustic test plans and the associated test levels. The methodology developed provides a major step toward the development of a realistic tool to quantitatively tailor test programs to specific payloads. Testing is considered at the no test, component, subassembly, or system level of assembly. Component redundancy and partial loss of flight data are considered. Most and probabilistic costs are considered, and incipient failures resulting from ground tests are treated. Optimums defining both component and assembly test levels are indicated for the modified test plans considered. modeling simplifications must be considered in interpreting the results relative to a particular payload. New parameters introduced were a no test option, flight by flight failure probabilities, and a cost to design components for higher vibration requirements. Parameters varied were the shuttle payload bay internal acoustic environment, the STS launch cost, the component retest/repair cost, and the amount of redundancy in the housekeeping section of the payload reliability model.

  8. Magnetic resonance urography in evaluation of duplicated renal collecting systems.

    PubMed

    Adeb, Melkamu; Darge, Kassa; Dillman, Jonathan R; Carr, Michael; Epelman, Monica

    2013-11-01

    Duplex renal collecting systems are common congenital anomalies of the upper urinary tract. In most cases they are incidental findings and not associated with additional pathologies. They demonstrate, however, higher incidences of hydroureteronephrosis, ureteroceles, and ectopic ureters. The most comprehensive morphologic and functional evaluation of duplex systems can be achieved using magnetic resonance urography. Functional magnetic resonance urography allows better separation of the renal poles, thus more accurate calculation of the differential renal functions compared with renal scintigraphy. Magnetic resonance urography is the study of choice when upper urinary tract anatomy is complex or when functional evaluation is needed.

  9. Radio frequency spectral characterization and model parameters extraction of high Q optical resonators

    PubMed Central

    Abdallah, Zeina; Boucher, Yann G.; Fernandez, Arnaud; Balac, Stéphane; Llopis, Olivier

    2016-01-01

    A microwave domain characterization approach is proposed to determine the properties of high quality factor optical resonators. This approach features a very high precision in frequency and aims to acquire a full knowledge of the complex transfer function (amplitude and phase) characterizing an optical resonator using a microwave vector network analyzer. It is able to discriminate between the different coupling regimes, from the under-coupling to the selective amplification, and it is used together with a model from which the main resonator parameters are extracted, i.e. coupling factor, intrinsic losses, phase slope, intrinsic and external quality factor. PMID:27251460

  10. The determination of electrical parameters of quartz crystal resonators with the consideration of dissipation.

    PubMed

    Wang, Ji; Zhao, Wenhua; Du, Jianke

    2006-12-22

    Recently, as the dissipation of quartz crystal through material viscosity is being considered in vibrations of piezoelectric plates, we have the opportunity to obtain electrical parameters from vibration solutions of a crystal plate representing an ideal resonator. Since the solutions are readily available with complex elastic constants from Mindlin plate equations for thickness-shear vibrations, the calculation of resistance and other parameters related to both mechanical deformation and electrical potential is straightforward. We start with the first-order Mindlin plate equations of a piezoelectric plate for the thickness-shear vibration analysis of a simple resonator model. The electrical parameters are derived with emphasis on the resistance that is related to the imaginary part of complex elastic constants, or the viscosity. All the electrical parameters are frequency dependent, enabling the study of the frequency behavior of crystal resonators with a direct formulation. Through the full consideration of complications like partial electrodes and supporting structures, we should be able obtain electrical parameters for practical applications in resonator design.

  11. Very Broad X(4260) and the Resonance Parameters of the ψ(3D) Vector Charmonium State

    NASA Astrophysics Data System (ADS)

    van Beveren, Eef; Rupp, George; Segovia, J.

    2010-09-01

    We argue that the X(4260) enhancement contains a wealth of information on 1-- cc¯ spectroscopy. We discuss the shape of the X(4260) observed in the Okubo-Zweig-Iizuka-forbidden process e+e-→π+π-J/ψ, in particular, at and near vector charmonium resonances as well as open-charm threshold enhancements. The resulting very broad X(4260) structure does not seem to classify itself as a 1-- cc¯ resonance, but its detailed shape allows us to identify new vector charmonium states with higher statistics than in open-charm decay. Here, we estimate the resonance parameters of the ψ(3D). Our approach also provides an explanation for the odd dip in the π+π-J/ψ data precisely at the ψ(4415) resonance.

  12. Very Broad X(4260) and the Resonance Parameters of the {psi}(3D) Vector Charmonium State

    SciTech Connect

    Beveren, Eef van; Rupp, George; Segovia, J.

    2010-09-03

    We argue that the X(4260) enhancement contains a wealth of information on 1{sup --} cc spectroscopy. We discuss the shape of the X(4260) observed in the Okubo-Zweig-Iizuka-forbidden process e{sup +}e{sup -}{yields}{pi}{sup +}{pi}{sup -}J/{psi}, in particular, at and near vector charmonium resonances as well as open-charm threshold enhancements. The resulting very broad X(4260) structure does not seem to classify itself as a 1{sup --} cc resonance, but its detailed shape allows us to identify new vector charmonium states with higher statistics than in open-charm decay. Here, we estimate the resonance parameters of the {psi}(3D). Our approach also provides an explanation for the odd dip in the {pi}{sup +}{pi}{sup -}J/{psi} data precisely at the {psi}(4415) resonance.

  13. New Resolved Resonance Region Evaluation for 63Cu and 65Cu for Nuclear Criticality Safety Program

    SciTech Connect

    Sobes, Vladimir; Leal, Luiz C; Guber, Klaus H; Forget, Benoit; Kopecky, S.; Schillebeeckx, P.; Siegler, P.

    2014-01-01

    A new resolved resonance region evaluation of 63Cu and 65Cu was done in the energy region from 10-5 eV to 99.5 keV. The R-Matrix SAMMY method using the Reich-Moore approximation was used to create a new set of consistent resonance parameters. The new evaluation was based on three experimental transmission data sets; two measured at ORELA and one from MITR, and two radiative capture experimental data sets from GELINA. A total of 141 new resonances were identied for 63Cu and 117 for 65Cu. The corresponding set of external resonances for each isotope was based on the identied resonances above 99.5 keV from the ORELA transmission data. The negative external levels (bound levels) were determined to match the dierential thermal cross section measured at the MITR. Double dierential elastic scattering cross sections were calculated from the new set of resonance parameters. Benchmarking calculations were carried out on a set of ICSBEP benchmarks. This work is in support of the DOE Nuclear Criticality Safety Program.

  14. New Resolved Resonance Region Evaluation for 63,65Cu for Nuclear Criticality Safety Program

    NASA Astrophysics Data System (ADS)

    Sobes, V.; Leal, L. C.; Guber, K.; Forget, B.; Kopecky, S.; Schillebeeckx, P.; Siegler, P.

    2014-04-01

    A new resolved resonance region evaluation of 63,65Cu was done in the energy region from 10-5 eV to 99.5 keV. The R-Matrix SAMMY method using the Reich-Moore approximation was used to create a new set of consistent resonance parameters. The new evaluation is based on three experimental transmission data sets: two measured at ORELA and one at MITR, plus two radiative capture experimental data sets from GELINA. A total of 141 new resonances were identified for 63Cu and 117 for 65Cu. The corresponding set of external resonances for each isotope is based on the identified resonances above 99.5 keV from the ORELA transmission data. The negative external levels (bound levels) have been determined to match the thermal cross section measured at the MITR. Differential elastic scattering cross sections have been calculated from the new set of resonance parameters. Benchmarking calculations were carried out on a set of ICSBEP benchmarks.

  15. Methodological aspects in the calculation of parity-violating effects in nuclear magnetic resonance parameters.

    PubMed

    Weijo, Ville; Bast, Radovan; Manninen, Pekka; Saue, Trond; Vaara, Juha

    2007-02-21

    We examine the quantum chemical calculation of parity-violating (PV) electroweak contributions to the spectral parameters of nuclear magnetic resonance (NMR) from a methodological point of view. Nuclear magnetic shielding and indirect spin-spin coupling constants are considered and evaluated for three chiral molecules, H2O2, H2S2, and H2Se2. The effects of the choice of a one-particle basis set and the treatment of electron correlation, as well as the effects of special relativity, are studied. All of them are found to be relevant. The basis-set dependence is very pronounced, especially at the electron correlated ab initio levels of theory. Coupled-cluster and density-functional theory (DFT) results for PV contributions differ significantly from the Hartree-Fock data. DFT overestimates the PV effects, particularly with nonhybrid exchange-correlation functionals. Beginning from third-row elements, special relativity is of importance for the PV NMR properties, shown here by comparing perturbational one-component and various four-component calculations. In contrast to what is found for nuclear magnetic shielding, the choice of the model for nuclear charge distribution--point charge or extended (Gaussian)--has a significant impact on the PV contribution to the spin-spin coupling constants.

  16. Stochastic Parameter Resonance of Road-Vehicle Systems and Related Bifurcation Problems

    NASA Astrophysics Data System (ADS)

    Wedig, Walter V.

    The paper investigates stochastic dynamics of road-vehicle systems and related bifurcation problems. The ride on rough roads generates vertical car vibrations whose root-mean-squares are resonant for critical car speeds and vanish when the car velocity is increasing, infinitely. These investigations are extended to wheel suspensions with progressive spring characteristics. For weak but still positive damping, the car vibrations become unstable when the velocity reaches the parameter resonance near twice the critical speed bifurcating into stochastic chaos of larger non-stationary car vibrations.

  17. Dependence of radial thermal diffusivity on parameters of toroidal plasma affected by resonant magnetic perturbations

    NASA Astrophysics Data System (ADS)

    Kanno, Ryutaro; Nunami, Masanori; Satake, Shinsuke; Takamaru, Hisanori; Okamoto, Masao

    2013-06-01

    We investigate how the neoclassical thermal diffusivity of an axisymmetric toroidal plasma is modified by the effect of resonant magnetic perturbations (RMPs), using a drift-kinetic simulation code for calculating the radial thermal diffusivity of ion in the perturbed region under an assumption of zero electric field. Here, the perturbed region is assumed to be generated on and near the resonance surfaces, and is wedged in between the regular closed magnetic surfaces. We find that the dependence of the radial thermal diffusivity on parameters of the toroidal plasma is represented as \\chi_r=\\chi_r^{(0)} \\{1+ c_0\\,(\\omega_b/\

  18. Pumping test evaluation of stream depletion parameters.

    PubMed

    Lough, Hilary K; Hunt, Bruce

    2006-01-01

    Descriptions are given of a pumping test and a corresponding analysis that permit calculation of all five hydrogeological parameters appearing in the Hunt (2003) solution for stream depletion caused by ground water abstraction from a well beside a stream. This solution assumes that flow in the pumped aquifer is horizontal, flow in the overlying aquitard or system of aquitards is vertical, and the free surface in the top aquitard is allowed to draw down. The definition of an aquitard in this paper is any layer with a vertical hydraulic conductivity much lower than the horizontal hydraulic conductivity of the pumped aquifer. These "aquitards" may be reasonably permeable layers but are distinguished from the pumped aquifer by their hydraulic conductivity contrast. The pumping test requires a complete set of drawdown measurements from at least one observation well. This well must be deep enough to penetrate the pumped aquifer, and pumping must continue for a sufficient time to ensure that depleted streamflow becomes a significant portion of the well abstraction rate. Furthermore, two of the five parameters characterize an aquitard that overlies the pumped aquifer, and values for these parameters are seen to be dependent upon the initial water table elevation in the aquitard. The field test analyzed herein used a total of eight observation wells screened in the pumped aquifer, and measurements from these wells gave eight sets of parameters that are used in a sensitivity analysis to determine the relative importance of each parameter in the stream depletion calculations.

  19. Evaluation of Control Parameters for the Activated Sludge Process

    ERIC Educational Resources Information Center

    Stall, T. Ray; Sherrard, Josephy H.

    1978-01-01

    An evaluation of the use of the parameters currently being used to design and operate the activated sludge process is presented. The advantages and disadvantages for the use of each parameter are discussed. (MR)

  20. Parameter-induced stochastic resonance based on spectral entropy and its application to weak signal detection

    SciTech Connect

    Zhang, Jinjing; Zhang, Tao

    2015-02-15

    The parameter-induced stochastic resonance based on spectral entropy (PSRSE) method is introduced for the detection of a very weak signal in the presence of strong noise. The effect of stochastic resonance on the detection is optimized using parameters obtained in spectral entropy analysis. Upon processing employing the PSRSE method, the amplitude of the weak signal is enhanced and the noise power is reduced, so that the frequency of the signal can be estimated with greater precision through spectral analysis. While the improvement in the signal-to-noise ratio is similar to that obtained using the Duffing oscillator algorithm, the computational cost reduces from O(N{sup 2}) to O(N). The PSRSE approach is applied to the frequency measurement of a weak signal made by a vortex flow meter. The results are compared with those obtained applying the Duffing oscillator algorithm.

  1. Evaluation Parameters for Computer-Adaptive Testing

    ERIC Educational Resources Information Center

    Georgiadou, Elisabeth; Triantafillou, Evangelos; Economides, Anastasios A.

    2006-01-01

    With the proliferation of computers in test delivery today, adaptive testing has become quite popular, especially when examinees must be classified into two categories (passfail, master nonmaster). Several well-established organisations have provided standards and guidelines for the design and evaluation of educational and psychological testing.…

  2. A parameter study of mode conversion at ion-ion hybrid resonances for ICRF-heating

    NASA Astrophysics Data System (ADS)

    Alava, M. J.; Heikkinen, J. A.

    1992-04-01

    By solving the wave equation for the radial electric field with constant poloidal electric field around the resonance layer of the fast Alfvén wave, various complex characteristics of mode conversion physics can be elucidated and analyzed for ion cyclotron heating of tokamaks. The validity of the Budden and tunnelling model [Ngan, Y. C. and Swanson, D. G., Phys. Fluids 20, 1920 (1977)] for the conversion studies is explored, and the conversion coefficient for the ion-ion hybrid resonance in the presence of cyclotron damping is found in closed form. The analytical results are compared with the numerical solution of the full wave equations expanded to second order in ion Larmor radius. It is found that the standard tunnelling solutions can be erroneous, not only in the case of strong damping, but also when the linearization of the plasma parameters around the resonance, peculiar to the tunnelling model, becomes inaccurate. The effects of the damping and cavity resonances on the conversion are separated in the derived analytical estimates, and the limits of the local theory of conversion are determined.

  3. Practice Parameter for Child and Adolescent Forensic Evaluations

    ERIC Educational Resources Information Center

    Journal of the American Academy of Child & Adolescent Psychiatry, 2011

    2011-01-01

    This Parameter addresses the key concepts that differentiate the forensic evaluation of children and adolescents from a clinical assessment. There are ethical issues unique to the forensic evaluation, because the forensic evaluator's duty is to the person, court, or agency requesting the evaluation, rather than to the patient. The forensic…

  4. Note: Modified π-type Butterworth-Van Dyke model for dual-mode Lamb-wave resonator with precise two-port Y-parameter characterizations

    NASA Astrophysics Data System (ADS)

    Wang, Yong; Hong, Yan; Goh, Wang Ling; Mu, Xiaojing

    2016-10-01

    Dual-mode Lamb-wave resonator has become a powerful component for clock reference and sensing applications, enabling efficient compensations of temperature effects, concurrent measurements of multiple environmental parameters, etc. An equivalent circuit model for the dual-mode Lamb-wave resonator is indispensable as it provides a means as well as being an effective tool for evaluating device characteristics and to aid the designing of circuitry for the resonators. This could be the first time ever that an efficient equivalent-circuit model, i.e., modified π-type Butterworth-Van Dyke model for dual-mode Lamb-wave resonators is reported. Evaluated by experiments, this model attains noteworthy agreements on both the magnitudes and phases of Y11 and Y21 of the measurement results. Compared to literature, the proposed model is capable of modeling the dual resonances efficiently. Moreover, this work also proves more accurate when viewing the Y-parameters across a wide frequency range. The gained features of this model are most beneficial for the analysis of the dual-mode Lamb-wave resonator and also for the designing of circuits.

  5. Note: Modified π-type Butterworth-Van Dyke model for dual-mode Lamb-wave resonator with precise two-port Y-parameter characterizations.

    PubMed

    Wang, Yong; Hong, Yan; Goh, Wang Ling; Mu, Xiaojing

    2016-10-01

    Dual-mode Lamb-wave resonator has become a powerful component for clock reference and sensing applications, enabling efficient compensations of temperature effects, concurrent measurements of multiple environmental parameters, etc. An equivalent circuit model for the dual-mode Lamb-wave resonator is indispensable as it provides a means as well as being an effective tool for evaluating device characteristics and to aid the designing of circuitry for the resonators. This could be the first time ever that an efficient equivalent-circuit model, i.e., modified π-type Butterworth-Van Dyke model for dual-mode Lamb-wave resonators is reported. Evaluated by experiments, this model attains noteworthy agreements on both the magnitudes and phases of Y11 and Y21 of the measurement results. Compared to literature, the proposed model is capable of modeling the dual resonances efficiently. Moreover, this work also proves more accurate when viewing the Y-parameters across a wide frequency range. The gained features of this model are most beneficial for the analysis of the dual-mode Lamb-wave resonator and also for the designing of circuits.

  6. Study of dual wavelength composite output of solid state laser based on adjustment of resonator parameters

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Nie, Jinsong; Wang, Xi; Hu, Yuze

    2016-10-01

    The 1064nm fundamental wave (FW) and the 532nm second harmonic wave (SHW) of Nd:YAG laser have been widely applied in many fields. In some military applications requiring interference in both visible and near-infrared spectrum range, the de-identification interference technology based on the dual wavelength composite output of FW and SHW offers an effective way of making the device or equipment miniaturized and low cost. In this paper, the application of 1064nm and 532nm dual-wavelength composite output technology in military electro-optical countermeasure is studied. A certain resonator configuration that can achieve composite laser output with high power, high beam quality and high repetition rate is proposed. Considering the thermal lens effect, the stability of this certain resonator is analyzed based on the theory of cavity transfer matrix. It shows that with the increase of thermal effect, the intracavity fundamental mode volume decreased, resulting the peak fluctuation of cavity stability parameter. To explore the impact the resonator parameters does to characteristics and output ratio of composite laser, the solid-state laser's dual-wavelength composite output models in both continuous and pulsed condition are established by theory of steady state equation and rate equation. Throughout theoretical simulation and analysis, the optimal KTP length and best FW transmissivity are obtained. The experiment is then carried out to verify the correctness of theoretical calculation result.

  7. Parameter optimization analysis to minimize the polarization error in a localized thermal tunable fiber ring resonator gyro.

    PubMed

    Bobbili, Prasada Rao; Nayak, Jagannath; Pinnoji, Prerana Dabral; Rama Koti Reddy, D V

    2016-03-10

    The accuracy of the resonant frequency servo loop is a major concern for the high-performance operation of a resonant fiber optic gyro. For instance, a bias error as large as tens or even hundreds of degrees/hour has been observed at the demodulated output of the resonant frequency servo loop. The traditional frequency servo mechanism is not an efficient tool to address this problem. In our previous work, we proposed a novel method to minimize the laser frequency noise to the level of the shot noise by refractive index modulation by a thermally tunable resonator. In this paper, we performed the parameter optimization for the resonator coil, multifunction integrated-optics chip, and couplers by the transition matrix using the Jones matrix methodology to minimize the polarization error. With the optimized parameter values, we achieved the bias value of the resonator fiber optic gyro to 1.924°/h.

  8. RIPL - Reference Input Parameter Library for Calculation of Nuclear Reactions and Nuclear Data Evaluations

    NASA Astrophysics Data System (ADS)

    Capote, R.; Herman, M.; Obložinský, P.; Young, P. G.; Goriely, S.; Belgya, T.; Ignatyuk, A. V.; Koning, A. J.; Hilaire, S.; Plujko, V. A.; Avrigeanu, M.; Bersillon, O.; Chadwick, M. B.; Fukahori, T.; Ge, Zhigang; Han, Yinlu; Kailas, S.; Kopecky, J.; Maslov, V. M.; Reffo, G.; Sin, M.; Soukhovitskii, E. Sh.; Talou, P.

    2009-12-01

    We describe the physics and data included in the Reference Input Parameter Library, which is devoted to input parameters needed in calculations of nuclear reactions and nuclear data evaluations. Advanced modelling codes require substantial numerical input, therefore the International Atomic Energy Agency (IAEA) has worked extensively since 1993 on a library of validated nuclear-model input parameters, referred to as the Reference Input Parameter Library (RIPL). A final RIPL coordinated research project (RIPL-3) was brought to a successful conclusion in December 2008, after 15 years of challenging work carried out through three consecutive IAEA projects. The RIPL-3 library was released in January 2009, and is available on the Web through http://www-nds.iaea.org/RIPL-3/. This work and the resulting database are extremely important to theoreticians involved in the development and use of nuclear reaction modelling (ALICE, EMPIRE, GNASH, UNF, TALYS) both for theoretical research and nuclear data evaluations. The numerical data and computer codes included in RIPL-3 are arranged in seven segments: MASSES contains ground-state properties of nuclei for about 9000 nuclei, including three theoretical predictions of masses and the evaluated experimental masses of Audi et al. (2003). DISCRETE LEVELS contains 117 datasets (one for each element) with all known level schemes, electromagnetic and γ-ray decay probabilities available from ENSDF in October 2007. NEUTRON RESONANCES contains average resonance parameters prepared on the basis of the evaluations performed by Ignatyuk and Mughabghab. OPTICAL MODEL contains 495 sets of phenomenological optical model parameters defined in a wide energy range. When there are insufficient experimental data, the evaluator has to resort to either global parameterizations or microscopic approaches. Radial density distributions to be used as input for microscopic calculations are stored in the MASSES segment. LEVEL DENSITIES contains

  9. Parameter allocation of parallel array bistable stochastic resonance and its application in communication systems

    NASA Astrophysics Data System (ADS)

    Liu, Jian; Wang, You-Guo; Zhai, Qi-Qing; Liu, Jin

    2016-10-01

    In this paper, we propose a parameter allocation scheme in a parallel array bistable stochastic resonance-based communication system (P-BSR-CS) to improve the performance of weak binary pulse amplitude modulated (BPAM) signal transmissions. The optimal parameter allocation policy of the P-BSR-CS is provided to minimize the bit error rate (BER) and maximize the channel capacity (CC) under the adiabatic approximation condition. On this basis, we further derive the best parameter selection theorem in realistic communication scenarios via variable transformation. Specifically, the P-BSR structure design not only brings the robustness of parameter selection optimization, where the optimal parameter pair is not fixed but variable in quite a wide range, but also produces outstanding system performance. Theoretical analysis and simulation results indicate that in the P-BSR-CS the proposed parameter allocation scheme yields considerable performance improvement, particularly in very low signal-to-noise ratio (SNR) environments. Project supported by the National Natural Science Foundation of China (Grant No. 61179027), the Qinglan Project of Jiangsu Province of China (Grant No. QL06212006), and the University Postgraduate Research and Innovation Project of Jiangsu Province (Grant Nos. KYLX15_0829, KYLX15_0831).

  10. Determination of acoustic nonlinearity parameter (β) using nonlinear resonance ultrasound spectroscopy: Theory and experiment.

    PubMed

    Chakrapani, Sunil Kishore; Barnard, Daniel J

    2017-02-01

    The present article investigates the possibility of using nonlinear resonance ultrasound spectroscopy to determine the acoustic nonlinearity parameter (β) and third order elastic constant by developing an inverse problem. A theoretical framework was developed for nonlinear forced vibration of a cantilever beam using material nonlinearity (stress-strain nonlinearity). The resulting nonlinear equation was solved using method of multiple time scales to obtain the nonlinear frequency shifts. The present works focuses only on classical nonlinearity and, therefore, a diverse group of intact, classic nonlinear materials were chosen. The samples were tested using nonlinear resonance ultrasound spectroscopy, and the developed theory was used to invert the experimental frequency shifts to obtain the nonlinearity parameters. The third order elastic constants and β were calculated using their analytical relationship with the nonlinearity parameter. The experimentally determined C111 and β values for all various materials agree well with literature values. In addition to determining β, determination of the sign, or phase of β was also explored theoretically and experimentally.

  11. Classification of hydrological parameter sensitivity and evaluation of parameter transferability across 431 US MOPEX basins

    NASA Astrophysics Data System (ADS)

    Ren, Huiying; Hou, Zhangshuan; Huang, Maoyi; Bao, Jie; Sun, Yu; Tesfa, Teklu; Ruby Leung, L.

    2016-05-01

    The Community Land Model (CLM) represents physical, chemical, and biological processes of the terrestrial ecosystems that interact with climate across a range of spatial and temporal scales. As CLM includes numerous sub-models and associated parameters, the high-dimensional parameter space presents a formidable challenge for quantifying uncertainty and improving Earth system predictions needed to assess environmental changes and risks. This study aims to evaluate the potential of transferring hydrologic model parameters in CLM through sensitivity analyses and classification across watersheds from the Model Parameter Estimation Experiment (MOPEX) in the United States. The sensitivity of CLM-simulated water and energy fluxes to hydrological parameters across 431 MOPEX basins are first examined using an efficient stochastic sampling-based sensitivity analysis approach. Linear, interaction, and high-order nonlinear impacts are all identified via statistical tests and stepwise backward removal parameter screening. The basins are then classified according to their parameter sensitivity patterns (internal attributes), as well as their hydrologic indices/attributes (external hydrologic factors) separately, using Principal component analysis (PCA) and expectation-maximization (EM) - based clustering approach. Similarities and differences among the parameter sensitivity-based classification system (S-Class), the hydrologic indices-based classification (H-Class), and the Koppen climate classification systems (K-Class) are discussed. Within each parameter sensitivity-based classification system (S-Class) with similar parameter sensitivity characteristics, similar inversion modeling setups can be used for parameter calibration, and the parameters and their contribution or significance to water and energy cycling may also be more transferrable. This classification study provides guidance on identifiable parameters, and on parameterization and inverse model design for CLM but the

  12. Relationships between nuclear magnetic resonance parameters used to characterize weathering spilled oil and soil toxicity in central Patagonia.

    PubMed

    Ríos, Stella Maris; Barquin, Mercedes; Katusich, Ofelia; Nudelman, Norma

    2014-01-01

    Oil spill in the Central Patagonian zone was studied to evaluate if any relationship exists between the parameters used to characterize weathering spilled oil and soil toxicity for two plant species and to evaluate if the phytotoxicity to local species would be a good index for the soil contamination. Nuclear magnetic resonance (NMR) structural indexes and column chromatography compositional indexes were determined to characterize the oil spill in the soil samples. Bioassays were also carried out using Lactuca sativa L (reference) and Atriplex lampa (native species) as test organisms. Measurements of the total petroleum hydrocarbon (TPH) and the electrical conductivity (EC) of the soil were carried out to evaluate the effect on the bioassays. The principal components analysis of the parameters determined by NMR, compositional indexes, EC, TPH, and toxicology data shows that the first three principal components accounted for the 78% of the total variance (40%, 25%, and 13% for the first, second, and third PC, respectively). A good agreement was found between information obtained by compositional indexes and NMR structural indexes. Soil toxicity increases with the increase of EC and TPH. Other factors, such as, the presence of branched and aromatic hydrocarbons is also significant. The statistical evaluation showed that the Euclidean distances (3D) between the background and each one of the samples might be a better indicator of the soil contamination, compared with chemical criterion of TPH.

  13. Exact two-component relativistic theory for nuclear magnetic resonance parameters.

    PubMed

    Sun, Qiming; Liu, Wenjian; Xiao, Yunlong; Cheng, Lan

    2009-08-28

    An exact two-component (X2C) relativistic theory for nuclear magnetic resonance parameters is obtained by first a single block-diagonalization of the matrix representation of the Dirac operator in a magnetic-field-dependent basis and then a magnetic perturbation expansion of the resultant two-component Hamiltonian and transformation matrices. Such a matrix formulation is not only simple but also general in the sense that the various ways of incorporating the field dependence can be treated in a unified manner. The X2C dia- and paramagnetic terms agree individually with the corresponding four-component ones up to machine accuracy for any basis.

  14. Symmetric Resonance Charge Exchange Cross Section Based on Impact Parameter Treatment

    NASA Technical Reports Server (NTRS)

    Omidvar, Kazem; Murphy, Kendrah; Atlas, Robert (Technical Monitor)

    2002-01-01

    Using a two-state impact parameter approximation, a calculation has been carried out to obtain symmetric resonance charge transfer cross sections between nine ions and their parent atoms or molecules. Calculation is based on a two-dimensional numerical integration. The method is mostly suited for hydrogenic and some closed shell atoms. Good agreement has been obtained with the results of laboratory measurements for the ion-atom pairs H+-H, He+-He, and Ar+-Ar. Several approximations in a similar published calculation have been eliminated.

  15. Longitudinal NMR parameter measurements of Japanese pear fruit during the growing process using a mobile magnetic resonance imaging system

    NASA Astrophysics Data System (ADS)

    Geya, Yuto; Kimura, Takeshi; Fujisaki, Hirotaka; Terada, Yasuhiko; Kose, Katsumi; Haishi, Tomoyuki; Gemma, Hiroshi; Sekozawa, Yoshihiko

    2013-01-01

    Longitudinal nuclear magnetic resonance (NMR) parameter measurements of Japanese pear fruit (Pyrus pyrifolia Nakai, Kosui) were performed using an electrically mobile magnetic resonance imaging (MRI) system with a 0.2 T and 16 cm gap permanent magnet. To measure the relaxation times and apparent diffusion coefficients of the pear fruit in relation to their weight, seven pear fruits were harvested almost every week during the cell enlargement period and measured in a research orchard. To evaluate the in situ relaxation times, six pear fruits were longitudinally measured for about two months during the same period. The measurements for the harvested samples showed good agreement with the in situ measurements. From the measurements of the harvested samples, it is clear that the relaxation rates of the pear fruits linearly change with the inverse of the linear dimension of the fruits, demonstrating that the relaxation mechanism is a surface relaxation. We therefore conclude that the mobile MRI system is a useful device for measuring the NMR parameters of outdoor living plants.

  16. A magnetic resonance imaging study on the articulatory and acoustic speech parameters of Malay vowels.

    PubMed

    Zourmand, Alireza; Mirhassani, Seyed Mostafa; Ting, Hua-Nong; Bux, Shaik Ismail; Ng, Kwan Hoong; Bilgen, Mehmet; Jalaludin, Mohd Amin

    2014-07-25

    The phonetic properties of six Malay vowels are investigated using magnetic resonance imaging (MRI) to visualize the vocal tract in order to obtain dynamic articulatory parameters during speech production. To resolve image blurring due to the tongue movement during the scanning process, a method based on active contour extraction is used to track tongue contours. The proposed method efficiently tracks tongue contours despite the partial blurring of MRI images. Consequently, the articulatory parameters that are effectively measured as tongue movement is observed, and the specific shape of the tongue and its position for all six uttered Malay vowels are determined.Speech rehabilitation procedure demands some kind of visual perceivable prototype of speech articulation. To investigate the validity of the measured articulatory parameters based on acoustic theory of speech production, an acoustic analysis based on the uttered vowels by subjects has been performed. As the acoustic speech and articulatory parameters of uttered speech were examined, a correlation between formant frequencies and articulatory parameters was observed. The experiments reported a positive correlation between the constriction location of the tongue body and the first formant frequency, as well as a negative correlation between the constriction location of the tongue tip and the second formant frequency. The results demonstrate that the proposed method is an effective tool for the dynamic study of speech production.

  17. [Fetal magnetic resonance imaging evaluation of congenital diaphragmatic hernia].

    PubMed

    Sebastià, C; Garcia, R; Gomez, O; Paño, B; Nicolau, C

    2014-01-01

    A diaphragmatic hernia is defined as the protrusion of abdominal viscera into the thoracic cavity through a normal or pathological orifice. The herniated viscera compress the lungs, resulting in pulmonary hypoplasia and secondary pulmonary hypertension, which are the leading causes of neonatal death in patients with congenital diaphragmatic hernia. Congenital diaphragmatic hernia is diagnosed by sonography in routine prenatal screening. Although magnetic resonance imaging is fundamentally used to determine whether the liver is located within the abdomen or has herniated into the thorax, it also can provide useful information about other herniated structures and the degree of pulmonary hypoplasia. The aim of this article is to review the fetal magnetic resonance findings for congenital diaphragmatic hernia and the signs that enable us to establish the neonatal prognosis when evaluating pulmonary hypoplasia.

  18. Evaluation of resonances above the proton threshold in 26Si

    NASA Astrophysics Data System (ADS)

    Chipps, K. A.

    2016-09-01

    26Al remains an intriguing target for observational gamma-ray astronomy, thanks to its characteristic decay. The 25Al(p, γ)26Si reaction is the crucial link in a sequence that bypasses the production of the observable 26Alg . s . in favor of the isomeric state, and as such has been the focus of many studies. Considerable confusion in this regard has arisen from the use of outdated excitation energies and masses in reaction studies and rate evaluations. Recalibration of existing data from the literature has resulted in updated excitation and resonance energies, but open questions remain, particularly with regard to spin assignments and partial widths/resonance strengths. A discussion of the levels just above the proton threshold in 26Si relevant to the astrophysical 25Al(p, γ)26Si reaction rate will be presented. This work is funded by the US Department of Energy, Office of Science, Office of Nuclear Physics.

  19. Theoretical calculations of Electron Paramagnetic Resonance parameters of liquid phase Orotic acid radical

    NASA Astrophysics Data System (ADS)

    Sarikaya, Ebru Karakaş; Dereli, Ömer

    2017-02-01

    To obtain liquid phase molecular structure, conformational analysis of Orotic acid was performed and six conformers were determined. For these conformations, eight possible radicals were modelled by using Density Functional Theory computations with respect to molecular structure. Electron Paramagnetic Resonance parameters of these model radicals were calculated and then they were compared with the experimental ones. Geometry optimizations of the molecule and modeled radicals were performed using Becke's three-parameter hybrid-exchange functional combined with the Lee-Yang-Parr correlation functional of Density Functional Theory and 6-311++G(d,p) basis sets in p-dioxane solution. Because Orotic acid can be mutagenic in mammalian somatic cells and it is also mutagenic for bacteria and yeast, it has been studied.

  20. CONTROL OF LASER RADIATION PARAMETERS: Enhancement of the efficiency and control of emission parameters of an unstable-resonator chemical oxygen—iodine laser

    NASA Astrophysics Data System (ADS)

    Boreisho, A. S.; Lobachev, V. V.; Savin, A. V.; Strakhov, S. Yu; Trilis, A. V.

    2007-07-01

    The outlook is considered for the development of a high-power supersonic flowing chemical oxygen—iodine laser operating as an amplifier and controlled by radiation from a master oscillator by using an unstable resonator with a hole-coupled mirror. The influence of the seed radiation intensity, the coupling-hole diameter, the active-medium length, and the magnification factor on the parameters of laser radiation is analysed. It is shown that the use of such resonators is most advisable in medium-power oxygen—iodine lasers for which classical unstable resonators are inefficient because of their low magnification factors. The use of unstable resonators with a hole-coupled mirror and injection provides the control of radiation parameters and a considerable increase in the output power and brightness of laser radiation.

  1. Practice parameter for child and adolescent forensic evaluations.

    PubMed

    Kraus, Louis J; Thomas, Christopher R; Bukstein, Oscar G; Walter, Heather J; Benson, R Scott; Chrisman, Allan; Farchione, Tiffany R; Hamilton, John; Keable, Helene; Kinlan, Joan; Schoettle, Ulrich; Siegel, Matthew; Stock, Saundra; Ptakowski, Kristin Kroeger; Medicus, Jennifer

    2011-12-01

    This Parameter addresses the key concepts that differentiate the forensic evaluation of children and adolescents from a clinical assessment. There are ethical issues unique to the forensic evaluation, because the forensic evaluator's duty is to the person, court, or agency requesting the evaluation, rather than to the patient. The forensic evaluator clarifies the legal questions to be answered and structures the evaluation to address those issues. The forensic examination may include a review of collateral information, interviews and other assessments of the child or adolescent, and interviews with other relevant informants. The principles in this Parameter suggest the general approach to the forensic evaluation of children and adolescents and are relevant to delinquency, child custody, child maltreatment, personal injury, and other court-ordered and noncourt-ordered evaluations.

  2. JUPITER PROJECT - JOINT UNIVERSAL PARAMETER IDENTIFICATION AND EVALUATION OF RELIABILITY

    EPA Science Inventory

    The JUPITER (Joint Universal Parameter IdenTification and Evaluation of Reliability) project builds on the technology of two widely used codes for sensitivity analysis, data assessment, calibration, and uncertainty analysis of environmental models: PEST and UCODE.

  3. Study and Optimization of CPT Resonance Parameters in 87 Rb/Ar/Ne Microcells Aimed for Application in Metrology

    NASA Astrophysics Data System (ADS)

    Masian, Y.; Sivak, A.; Sevostianov, D.; Vassiliev, V.; Velichansky, V.

    The paper shows the presents results of studies of small-size rubidium cells with argon and neon buffer gases, produced by a patent pended technique of laser welding [Fishman et al. (2014)]. Cells were designed for miniature frequency standard. Temperature dependence of the frequency of the coherent population trapping (CPT) resonance was measured and used to optimize the ratio of partial pressures of buffer gases. The influence of duration and regime of annealing on the CPT-resonance frequency drift was investigated. The parameters of the FM modulation of laser current for two cases which correspond to the highest amplitude of CPT resonance and to the smallest light shifts of the resonance frequency were determined. The temperature dependences of the CPT resonance frequency were found to be surprisingly different in the two cases. A non-linear dependence of CPT resonance frequency on the temperature of the cell with the two extremes was revealed for one of these cases.

  4. Prediction of hydraulic parameters from block joint inversion of magnetic resonance and vertical electric soundings

    NASA Astrophysics Data System (ADS)

    Günther, T.; Müller-Petke, M.

    2012-04-01

    For assessing the impact of climate changes on salinity of coastal aquifers, numerical modelling needs to be done. As input, the spatial distribution of the parameters porosity, hydraulic conductivity and salt concentrations is needed. Airborne resistivity data are available that gives hints to fluid conductivity. Magnetic resonance soundings (MRS) can provide free water content directly yielding porosity, which in turn is needed for fluid conductivities and thus TDS concentrations. Furthermore, hydraulic conductivities can be retrieved by empirical relations using porosity and decay times. For having a unique model with all three primary parameters, vertical electrical and magnetic resonance soundings are inverted jointly using a block discretization. The MRS data were preprocessed using noise cancellation, despiking and a new gate integration scheme. Data errors were derived from fitting and include the effect of gating. Since the resistivity model affects the MRS inversion but demands an extensive kernel calculation, resistivity is updated only once. After inversion, a systematic model variation is done in order to retrieve confidence intervals of the primary and secondary parameters. We apply the methodology to several soundings at the North Sea Island Borkum, where the dynamics of the fresh/salt water interface is currently investigated. All soundings exhibit a very good data quality. One sounding close to a research borehole verifies the approach qualitatively. Another sounding was done to calibrate the petrophysical parameters using a pumping test. Finally, it is applied to a sounding in the flooding area. Whereas single MRS and VES data can be explained by a 3-layer and 4-layer model, respectively, a 5-layer model is needed to find a comprehensive model. Even though porosities are fairly constant, we can distinguish lithology and salinity due to the combination of resistivity and decay time. This case shows two fresh/salt water interfaces separated by a

  5. Thoracic magnetic resonance imaging for the evaluation of pulmonary emphysema.

    PubMed

    Lee, Sang Min; Seo, Joon Beom; Hwang, Hye Jeon; Kim, Eun Young; Oh, Sang Young; Kim, Ji-Eun

    2013-05-01

    Pulmonary emphysema is a pathologic condition characterized by permanently enlarged airspaces distal to the terminal bronchiole with destruction of the alveolar walls. Functional information of the lungs is important to understand the pathophysiology of emphysema and that of chronic obstructive pulmonary disease. With the recent developments in magnetic resonance imaging (MRI) techniques, functional MRI with variable MR sequences can be used for the evaluation of different physiological and anatomic changes seen in cases of pulmonary emphysema. In this review article, we will focus on a brief description of each method, results of some of the most recent work, and the clinical application of such knowledge.

  6. Computed tomography and magnetic resonance imaging evaluation of pericardial disease

    PubMed Central

    Shahid, Muhammad; Watkin, Richard W.

    2016-01-01

    Pericardial diseases are commonly encountered in clinical practice and may present as an isolated process or in association with various systemic conditions. Traditionally transthoracic echocardiography (TTE) has been the method of choice for the evaluation of suspected pericardial disease but increasingly computed tomography (CT) and magnetic resonance imaging (MRI) are also being used as part of a rational multi-modality imaging approach tailored to the specific clinical scenario. This paper reviews the role of CT and MRI across the spectrum of pericardial diseases. PMID:27429911

  7. Estimation of water retention parameters from nuclear magnetic resonance relaxation time distributions

    PubMed Central

    Costabel, Stephan; Yaramanci, Ugur

    2013-01-01

    [1] For characterizing water flow in the vadose zone, the water retention curve (WRC) of the soil must be known. Because conventional WRC measurements demand much time and effort in the laboratory, alternative methods with shortened measurement duration are desired. The WRC can be estimated, for instance, from the cumulative pore size distribution (PSD) of the investigated material. Geophysical applications of nuclear magnetic resonance (NMR) relaxometry have successfully been applied to recover PSDs of sandstones and limestones. It is therefore expected that the multiexponential analysis of the NMR signal from water-saturated loose sediments leads to a reliable estimation of the WRC. We propose an approach to estimate the WRC using the cumulative NMR relaxation time distribution and approximate it with the well-known van-Genuchten (VG) model. Thereby, the VG parameter n, which controls the curvature of the WRC, is of particular interest, because it is the essential parameter to predict the relative hydraulic conductivity. The NMR curves are calibrated with only two conventional WRC measurements, first, to determine the residual water content and, second, to define a fixed point that relates the relaxation time to a corresponding capillary pressure. We test our approach with natural and artificial soil samples and compare the NMR-based results to WRC measurements using a pressure plate apparatus and to WRC predictions from the software ROSETTA. We found that for sandy soils n can reliably be estimated with NMR, whereas for samples with clay and silt contents higher than 10% the estimation fails. This is the case when the hydraulic properties of the soil are mainly controlled by the pore constrictions. For such samples, the sensitivity of the NMR method for the pore bodies hampers a plausible WRC estimation. Citation: Costabel, S., and U. Yaramanci (2013), Estimation of water retention parameters from nuclear magnetic resonance relaxation time distributions, Water

  8. Classification of hydrological parameter sensitivity and evaluation of parameter transferability across 431 US MOPEX basins

    SciTech Connect

    Ren, Huiying; Hou, Zhangshuan; Huang, Maoyi; Bao, Jie; Sun, Yu; Tesfa, Teklu K.; Leung, Lai-Yung R.

    2016-02-27

    The Community Land Model (CLM) represents physical, chemical, and biological processes of the terrestrial ecosystems that interact with climate across a range of spatial and temporal scales. As CLM includes numerous sub-models and associated parameters, the high-dimensional parameter space presents a formidable challenge for quantifying uncertainty and improving Earth system predictions needed to assess environmental changes and risks. This study aims to evaluate the potential of transferring hydrologic model parameters in CLM through sensitivity analyses and classification across watersheds from the Model Parameter Estimation Experiment (MOPEX) in the United States. The sensitivity of CLM-simulated water and energy fluxes to hydrological parameters across 431 MOPEX basins are first examined using an efficient stochastic sampling-based sensitivity analysis approach. Linear, interaction, and high-order nonlinear impacts are all identified via statistical tests and stepwise backward removal parameter screening. The basins are then classified accordingly to their parameter sensitivity patterns (internal attributes), as well as their hydrologic indices/attributes (external hydrologic factors) separately, using a Principal component analyses (PCA) and expectation-maximization (EM) –based clustering approach. Similarities and differences among the parameter sensitivity-based classification system (S-Class), the hydrologic indices-based classification (H-Class), and the Koppen climate classification systems (K-Class) are discussed. Within each S-class with similar parameter sensitivity characteristics, similar inversion modeling setups can be used for parameter calibration, and the parameters and their contribution or significance to water and energy cycling may also be more transferrable. This classification study provides guidance on identifiable parameters, and on parameterization and inverse model design for CLM but the methodology is applicable to other models

  9. Parameter analysis for a nuclear magnetic resonance gyroscope based on 133Cs–129Xe/131Xe

    NASA Astrophysics Data System (ADS)

    Zhang, Da-Wei; Xu, Zheng-Yi; Zhou, Min; Xu, Xin-Ye

    2017-02-01

    We theoretically investigate several parameters for the nuclear magnetic resonance gyroscope based on 133Cs–129Xe/131Xe. For a cell containing a mixture of 133Cs at saturated pressure, we investigate the optimal quenching gas (N2) pressure and the corresponding pump laser intensity to achieve 30% 133Cs polarization at the center of the cell when the static magnetic field B 0 is 5 {{μ }}{{T}} with different 129Xe/131Xe pressure. The effective field produced by spin-exchange polarized 129Xe or 131Xe sensed by 133Cs can also be discussed in different 129Xe/131Xe pressure conditions. Furthermore, the relationship between the detected signal and the probe laser frequency is researched. We obtain the optimum probe laser detuning from the D2 (6{}2{{S}}1/2\\to 6{}2{{P}}3/2) resonance with different 129Xe/131Xe pressure owing to the pressure broadening. Project supported by the National High Technology Research and Development Program of China (Grant No. 2014AA123401), the National Key Basic Research and Development Program of China (Grant Nos. 2016YFA0302103 and 2012CB821302), the National Natural Science Foundation of China (Grant 11134003), and Shanghai Excellent Academic Leaders Program of China (Grant No. 12XD1402400).

  10. Elbow magnetic resonance imaging: imaging anatomy and evaluation.

    PubMed

    Hauptfleisch, Jennifer; English, Collette; Murphy, Darra

    2015-04-01

    The elbow is a complex joint. Magnetic resonance imaging (MRI) is often the imaging modality of choice in the workup of elbow pain, especially in sports injuries and younger patients who often have either a history of a chronic repetitive strain such as the throwing athlete or a distinct traumatic injury. Traumatic injuries and alternative musculoskeletal pathologies can affect the ligaments, musculotendinous, cartilaginous, and osseous structures of the elbow as well as the 3 main nerves to the upper limb, and these structures are best assessed with MRI.Knowledge of the complex anatomy of the elbow joint as well as patterns of injury and disease is important for the radiologist to make an accurate diagnosis in the setting of elbow pain. This chapter will outline elbow anatomy, basic imaging parameters, compartmental pathology, and finally applications of some novel MRI techniques.

  11. Determination of molecular spectroscopic parameters and energy-transfer rates by double-resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Steinfeld, J. I.; Foy, B.; Hetzler, J.; Flannery, C.; Klaassen, J.; Mizugai, Y.; Coy, S.

    1990-05-01

    The spectroscopy of small to medium-size polyatomic molecules can be extremely complex, especially in higher-lying overtone and combination vibrational levels. The high density of levels also complicates the understanding of inelastic collision processes, which is required to model energy transfer and collision broadening of spectral lines. Both of these problems can be addressed by double-resonance spectroscopy, i.e., time-resolved pump-probe measurements using microwave, infrared, near-infrared, and visible-wavelength sources. Information on excited-state spectroscopy, transition moments, inelastic energy transfer rates and propensity rules, and pressure-broadening parameters may be obtained from such experiments. Examples are given for several species of importance in planetary atmospheres, including ozone, silane, ethane, and ammonia.

  12. Neutron capture on Zr94: Resonance parameters and Maxwellian-averaged cross sections

    NASA Astrophysics Data System (ADS)

    Tagliente, G.; Milazzo, P. M.; Fujii, K.; Abbondanno, U.; Aerts, G.; Álvarez, H.; Alvarez-Velarde, F.; Andriamonje, S.; Andrzejewski, J.; Audouin, L.; Badurek, G.; Baumann, P.; Bečvář, F.; Belloni, F.; Berthoumieux, E.; Bisterzo, S.; Calviño, F.; Calviani, M.; Cano-Ott, D.; Capote, R.; Carrapiço, C.; Cennini, P.; Chepel, V.; Chiaveri, E.; Colonna, N.; Cortes, G.; Couture, A.; Cox, J.; Dahlfors, M.; David, S.; Dillmann, I.; Domingo-Pardo, C.; Dridi, W.; Duran, I.; Eleftheriadis, C.; Embid-Segura, M.; Ferrari, A.; Ferreira-Marques, R.; Furman, W.; Gallino, R.; Goncalves, I.; Gonzalez-Romero, E.; Gramegna, F.; Guerrero, C.; Gunsing, F.; Haas, B.; Haight, R.; Heil, M.; Herrera-Martinez, A.; Jericha, E.; Käppeler, F.; Kadi, Y.; Karadimos, D.; Karamanis, D.; Kerveno, M.; Kossionides, E.; Krtička, M.; Lamboudis, C.; Leeb, H.; Lindote, A.; Lopes, I.; Lozano, M.; Lukic, S.; Marganiec, J.; Marrone, S.; Martínez, T.; Massimi, C.; Mastinu, P.; Mengoni, A.; Moreau, C.; Mosconi, M.; Neves, F.; Oberhummer, H.; O'Brien, S.; Pancin, J.; Papachristodoulou, C.; Papadopoulos, C.; Paradela, C.; Patronis, N.; Pavlik, A.; Pavlopoulos, P.; Perrot, L.; Pigni, M. T.; Plag, R.; Plompen, A.; Plukis, A.; Poch, A.; Praena, J.; Pretel, C.; Quesada, J.; Rauscher, T.; Reifarth, R.; Rosetti, M.; Rubbia, C.; Rudolf, G.; Rullhusen, P.; Salgado, J.; Santos, C.; Sarchiapone, L.; Savvidis, I.; Stephan, C.; Tain, J. L.; Tassan-Got, L.; Tavora, L.; Terlizzi, R.; Vannini, G.; Vaz, P.; Ventura, A.; Villamarin, D.; Vincente, M. C.; Vlachoudis, V.; Vlastou, R.; Voss, F.; Walter, S.; Wiescher, M.; Wisshak, K.

    2011-07-01

    The neutron capture cross sections of the Zr isotopes play an important role in nucleosynthesis studies. The s-process reaction flow between the Fe seed and the heavier isotopes passes through the neutron magic nucleus Zr90 and through Zr91,92,93,94, but only part of the flow extends to Zr96 because of the branching point at Zr95. Apart from their effect on the s-process flow, the comparably small isotopic (n,γ) cross sections make Zr also an interesting structural material for nuclear reactors. The Zr94 (n,γ) cross section has been measured with high resolution at the spallation neutron source n_TOF at CERN and resonance parameters are reported up to 60 keV neutron energy.

  13. Contributions of structural connectivity and cerebrovascular parameters to functional magnetic resonance imaging signals in mice at rest and during sensory paw stimulation.

    PubMed

    Schroeter, Aileen; Grandjean, Joanes; Schlegel, Felix; Saab, Bechara J; Rudin, Markus

    2016-01-01

    Previously, we reported widespread bilateral increases in stimulus-evoked functional magnetic resonance imaging signals in mouse brain to unilateral sensory paw stimulation. We attributed the pattern to arousal-related cardiovascular changes overruling cerebral autoregulation thereby masking specific signal changes elicited by local neuronal activity. To rule out the possibility that interhemispheric neuronal communication might contribute to bilateral functional magnetic resonance imaging responses, we compared stimulus-evoked functional magnetic resonance imaging responses to unilateral hindpaw stimulation in acallosal I/LnJ, C57BL/6, and BALB/c mice. We found bilateral blood-oxygenation-level dependent signal changes in all three strains, ruling out a dominant contribution of transcallosal communication as reason for bilaterality. Analysis of functional connectivity derived from resting-state functional magnetic resonance imaging, revealed that bilateral cortical functional connectivity is largely abolished in I/LnJ animals. Cortical functional connectivity in all strains correlated with structural connectivity in corpus callosum as revealed by diffusion tensor imaging. Given the profound influence of systemic hemodynamics on stimulus-evoked functional magnetic resonance imaging outcomes, we evaluated whether functional connectivity data might be affected by cerebrovascular parameters, i.e. baseline cerebral blood volume, vascular reactivity, and reserve. We found that effects of cerebral hemodynamics on functional connectivity are largely outweighed by dominating contributions of structural connectivity. In contrast, contributions of transcallosal interhemispheric communication to the occurrence of ipsilateral functional magnetic resonance imaging response of equal amplitude to unilateral stimuli seem negligible.

  14. Classification of hydrological parameter sensitivity and evaluation of parameter transferability across 431 US MOPEX basins

    SciTech Connect

    Ren, Huiying; Hou, Zhangshuan; Huang, Maoyi; Bao, Jie; Sun, Yu; Tesfa, Teklu; Ruby Leung, L.

    2016-05-01

    Effective uncertainty quantification approaches are needed to identify important parameters or factors that affect complex Earth system models that composed of multi-phase multi-component phenomena and multiple biogeophysical-biogeochemical processes. In this study, the impacts of 10 hydrologic parameters in Community Land Model (CLM) simulations of runoff and latent heat flux in a watershed are evaluated. Simple residual statistics, the Nash-Sutcliffe coefficient, and log mean square error are used as alternative measures of the deviations between the simulated and field observed values. The effects of the input parameters on the deviations are evaluated quantitatively using analysis of variance (ANOVA) based on the generalized linear model (GLM), and using generalized cross validation (GCV) based on the multivariate adaptive regression splines (MARS) model. These analyses 1) help identify how to adjust parameter values and therefore the calibration of the CLM parameters and to improve the model’s simulations, and 2) can approximately predict the model calibration performance. The convergence behavior of the sensitivity analysis with number of sampling points for both ANOVA and GCV is also examined relative to different combinations of input parameters and output response variables and their metrics.

  15. Evaluation of muscle injury using magnetic resonance imaging

    NASA Technical Reports Server (NTRS)

    LeBlanc, A. D.; Jaweed, M.; Evans, H.

    1993-01-01

    The objective of this study was to investigate spin echo T2 relaxation time changes in thigh muscles after intense eccentric exercise in healthy men. Spin echo and calculated T2 relaxation time images of the thighs were obtained on several occasions after exercise of one limb; the contralateral limb served as control. Muscle damage was verified by elevated levels of serum creatine kinase (CK). Thirty percent of the time no exercise effect was discernible on the magnetic resonance (MR) images. In all positive MR images (70%) the semitendinosus muscle was positive, while the biceps femoris, short head, and gracilis muscles were also positive in 50% and 25% of the total cases, respectively. The peak T2 relaxation time and serum CK were correlated (r = 0.94, p<0.01); temporal changes in muscle T2 relaxation time and serum CK were similar, although T2 relaxation time remained positive after serum CK returned to background levels. We conclude that magnetic resonance imaging can serve as a useful tool in the evaluation of eccentric exercise muscle damage by providing a quantitative indicator of damage and its resolution as well as the specific areas and muscles.

  16. Diagnostics of recombining laser plasma parameters based on He-like ion resonance lines intensity ratios

    NASA Astrophysics Data System (ADS)

    Ryazantsev, S. N.; Skobelev, I. Yu; Faenov, A. Ya; Pikuz, T. A.; Grum-Grzhimailo, A. N.; Pikuz, S. A.

    2016-11-01

    While the plasma created by powerful laser expands from the target surface it becomes overcooled, i.e. recombining one. Improving of diagnostic methods applicable for such plasma is rather important problem in laboratory astrophysics nowadays because laser produced jets are fully scalable to young stellar objects. Such scaling is possible because of the plasma hydrodynamic equations invariance under some transformations. In this paper it is shown that relative intensities of the resonance transitions in He-like ions can be used to measure the parameters of recombining plasma. Intensity of the spectral lines corresponding to these transitions is sensitive to the density in the range of 1016-1020 cm-3 while the temperature ranges from 10 to 100 eV for ions with nuclear charge Zn ∼ 10. Calculations were carried out for F VIII ion and allowed to determine parameters of plasma jets created by nanosecond laser system ELFIE (Ecole Polytechnique, France) for astrophysical phenomenon modelling. Obtained dependencies are quite universal and can be used for any recombining plasma containing He-like fluorine ions.

  17. Density functional theory computation of Nuclear Magnetic Resonance parameters in light and heavy nuclei

    NASA Astrophysics Data System (ADS)

    Sutter, Kiplangat

    This thesis illustrates the utilization of Density functional theory (DFT) in calculations of gas and solution phase Nuclear Magnetic Resonance (NMR) properties of light and heavy nuclei. Computing NMR properties is still a challenge and there are many unknown factors that are still being explored. For instance, influence of hydrogen-bonding; thermal motion; vibration; rotation and solvent effects. In one of the theoretical studies of 195Pt NMR chemical shift in cisplatin and its derivatives illustrated in Chapter 2 and 3 of this thesis. The importance of representing explicit solvent molecules explicitly around the Pt center in cisplatin complexes was outlined. In the same complexes, solvent effect contributed about half of the J(Pt-N) coupling constant. Indicating the significance of considering the surrounding solvent molecules in elucidating the NMR measurements of cisplatin binding to DNA. In chapter 4, we explore the Spin-Orbit (SO) effects on the 29Si and 13C chemical shifts induced by surrounding metal and ligands. The unusual Ni, Pd, Pt trends in SO effects to the 29Si in metallasilatrane complexes X-Si-(mu-mt)4-M-Y was interpreted based on electronic and relativistic effects rather than by structural differences between the complexes. In addition, we develop a non-linear model for predicting NMR SO effects in a series of organics bonded to heavy nuclei halides. In chapter 5, we extend the idea of "Chemist's orbitals" LMO analysis to the quantum chemical proton NMR computation of systems with internal resonance-assisted hydrogen bonds. Consequently, we explicitly link the relationship between the NMR parameters related to H-bonded systems and intuitive picture of a chemical bond from quantum calculations. The analysis shows how NMR signatures characteristic of H-bond can be explained by local bonding and electron delocalization concepts. One shortcoming of some of the anti-cancer agents like cisplatin is that they are toxic and researchers are looking for

  18. Evaluation of hail suppression programme effectiveness using radar derived parameters

    NASA Astrophysics Data System (ADS)

    Tani, Satyanarayana; Paulitsch, Helmut; Teschl, Reinhard; Süsser-Rechberger, Barbara

    2016-04-01

    The objective of this study is evaluating "the operational hail suppression programme" in the province of Styria, Austria "for the year 2015". For the evaluation purpose the HAILSYS software tool was developed by integrating single polarization C-band weather radar data, aircraft trajectory, radiosonde freezing level data, hail events and crop damages information from the ground. The hail related radar derived parameters are: hail mass aloft, hail mass flux, probability of hail, vertical integrated hail mass, hail kinetic energy flux, and storm severity index. The spatial maps of hail kinetic energy and hail mass were developed to evaluate the seeding effect. The time history plots of vertical integrated hail mass, hail mass aloft and the probability of hail are drawn over an entire cell lifetime. The sensitivity and variation of radar hail parameters over time and associated changes due to cloud seeding will be presented.

  19. Treatment time reduction through parameter optimization in magnetic resonance guided high intensity focused ultrasound treatments

    NASA Astrophysics Data System (ADS)

    Coon, Joshua

    Magnetic Resonance guided High Intensity Focused Ultrasound (MRgHIFU) treatments are a promising modality for cancer treatments in which a focused beam of ultrasound energy is used to kill tumor tissue. However, obstacles still exist to its widespread clinical implementation, including long treatment times. This research demonstrates reductions in treatment times through intelligent selection of the user-controllable parameters, including: the focal zone treatment path, focal zone size, focal zone spacing, and whether to treat one or several focal zone locations at any given time. Several treatments using various combinations of these parameters were simulated using a finite difference method to solve the Pennes bio-heat transfer equation for an ultrasonically heated tissue region with a wide range of acoustic, thermal, geometric, and tumor properties. The total treatment time was iteratively optimized using either a heuristic method or routines included in the Matlab software package, with constraints imposed for patient safety and treatment efficacy. The results demonstrate that large reductions in treatment time are possible through the intelligent selection of user-controllable treatment parameters. For the treatment path, treatment times are reduced by as much as an order of magnitude if the focal zones are arranged into stacks along the axial direction and a middle-front-back ordering is followed. For situations where normal tissue heating constraints are less stringent, these focal zones should have high levels of adjacency to further decrease treatment times; however, adjacency should be reduced in some cases where normal tissue constraints are more stringent. Also, the use of smaller, more concentrated focal zones produces shorter treatment times than larger, more diluted focal zones, a result verified in an agar phantom model. Further, focal zones should be packed using only a small amount of overlap in the axial direction and with a small gap in the

  20. Crossing resonance of wave fields in a medium with an inhomogeneous coupling parameter

    SciTech Connect

    Ignatchenko, V. A. Polukhin, D. S.

    2013-11-15

    The dynamic susceptibilities (Green functions) of the system of two coupled wave fields of different physical natures in a medium with an arbitrary relation between the mean value ε and rms fluctuation Δε of the coupling parameter have been examined. The self-consistent approximation involving all diagrams with noncrossing correlation lines has been developed for the case where the initial Green’s function of the homogeneous medium describes the system of coupled wave fields. The analysis has been performed for spin and elastic waves. Expressions have been obtained for the diagonal elements G{sub mm} and G{sub uu} of the matrix Green’s function, which describe spin and elastic waves in the case of magnetic and elastic excitations, and for the off-diagonal elements G{sub mu} and G{sub um}, which describe these waves in the case of cross excitation. Change in the forms of these elements has been numerically studied for the case of one-dimensional inhomogeneities with an increase in Δε and with a decrease in ε under the condition that the sum of the squares of these quantities is conserved: two peaks in the frequency dependences of imaginary parts of G{sub mm} and G{sub uu} are broadened and then joined into one broad peak; a fine structure appears in the form of narrow resonance at the vertex of the Green’s function of one wave field and narrow antiresonance at the vertex of the Green function of the other field; peaks of the fine structure are broadened and then disappear with an increase in the correlation wavenumber of the inhomogeneities of the coupling parameter; and the amplitudes of the off-diagonal elements vanish in the limit ε → 0.

  1. Variability of Schumann resonance parameters observed at low latitude stations in China

    NASA Astrophysics Data System (ADS)

    Ouyang, X.-Y.; Xiao, Z.; Hao, Y.-Q.; Zhang, D.-H.

    2015-10-01

    This paper presents a comprehensive analysis of the Schumann resonance (SR) parameters observed at low latitude stations in China for the first time. Variations of SR peak frequency and intensity on different timescales (from minutes to years) are analyzed in detail. Diurnal and seasonal variations are shown and the source-observer distance is calculated to confirm the contributions of lightning activity. Differences in the profiles of SR intensity between the NS and EW components are due to the effects of the source-observer distance and the relative position of the observer to the sources. Diurnal frequency variations are more complicated and cannot be directly linked with the three thunderstorm centers. Seasonal variations are clear for intensity but not for frequency. The differences in the diurnal and seasonal variations between the SR intensity and frequency show that the greatest contributor to SR intensity is global lightning activity, while the SR frequency is not affected solely by lightning, as certain other factors involving ionosphere properties may play non-negligible roles. We also emphasize that our observations do not show a distinct day-night change in the SR parameters, and that the SR intensity does not show abrupt changes across terminators. This observation is consistent with previous simulations. Finally, the response of the SR to a solar flare is discussed. The flare leads to a sudden increase of about 0.2 Hz relative to the 2σ level of the SR frequencies in the first three modes, which is in agreement with other works in the literature. This frequency enhancement is explained using theoretical calculations.

  2. A Mathematical Assessment of the Precision of Parameters in Measuring Resonance Spectra

    NASA Astrophysics Data System (ADS)

    Golding, Elke M.; Golding, Raymund M.

    1998-12-01

    The accurate interpretation ofin vivomagnetic resonance spectroscopy (MRS) spectra requires a complete understanding of the associated noise-induced errors. In this paper, we address the effect of complex correlated noise patterns on the measurement of a set ofpeakparameters. This is examined initially at the level of a single spectral analysis followed by addressing the noise-induced errors associated with determining thesignalparameters from thepeakparameters. We describe a relatively simple method for calculating these errors for any correlated noise pattern in terms of the noise standard deviation and correlation length. The results are presented in such a way that an estimate of the errors may be made from a single MRS spectrum. We also explore how, under certain circumstances, the lineshape of the signal may be determined. We then apply these results to reexamine a set ofin vivo31P MRS spectra obtained from rat brain prior to and following moderate fluid percussion injury. The approach outlined in this paper will demonstrate how meaningful results may be obtained from spectra where the signal-to-noise ratio (SNR) is quite small and where knowledge of the precise shape of the signal and the detail of the noise pattern is unknown. In essence, we show how to determine the expected errors in the spectral parameters from an estimate of the SNR from a single spectrum, thereby allowing a more discriminative interpretation of the data.

  3. Measurement of resonance parameters of orbitally excited narrow B0 mesons.

    PubMed

    Aaltonen, T; Adelman, J; Akimoto, T; Albrow, M G; González, B Alvarez; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Apresyan, A; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Aurisano, A; Azfar, F; Azzurri, P; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Bartsch, V; Bauer, G; Beauchemin, P-H; Bedeschi, F; Beecher, D; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Beringer, J; Bhatti, A; Binkley, M; Bisello, D; Bizjak, I; Blair, R E; Blocker, C; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bolla, G; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Bridgeman, A; Brigliadori, L; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Budd, S; Burke, S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Byrum, K L; Cabrera, S; Calancha, C; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carls, B; Carlsmith, D; Carosi, R; Carrillo, S; Carron, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavaliere, V; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, K; Chokheli, D; Chou, J P; Choudalakis, G; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Chwalek, T; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Compostella, G; Convery, M E; Conway, J; Cordelli, M; Cortiana, G; Cox, C A; Cox, D J; Crescioli, F; Almenar, C Cuenca; Cuevas, J; Culbertson, R; Cully, J C; Dagenhart, D; Datta, M; Davies, T; de Barbaro, P; De Cecco, S; Deisher, A; De Lorenzo, G; Dell'orso, M; Deluca, C; Demortier, L; Deng, J; Deninno, M; Derwent, P F; di Giovanni, G P; Dionisi, C; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Donati, S; Dong, P; Donini, J; Dorigo, T; Dube, S; Efron, J; Elagin, A; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Ferrazza, C; Field, R; Flanagan, G; Forrest, R; Frank, M J; Franklin, M; Freeman, J C; Furic, I; Gallinaro, M; Galyardt, J; Garberson, F; Garcia, J E; Garfinkel, A F; Genser, K; Gerberich, H; Gerdes, D; Gessler, A; Giagu, S; Giakoumopoulou, V; Giannetti, P; Gibson, K; Gimmell, J L; Ginsburg, C M; Giokaris, N; Giordani, M; Giromini, P; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Grinstein, S; Grosso-Pilcher, C; Grundler, U; da Costa, J Guimaraes; Gunay-Unalan, Z; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Han, B-Y; Han, J Y; Happacher, F; Hara, K; Hare, D; Hare, M; Harper, S; Harr, R F; Harris, R M; Hartz, M; Hatakeyama, K; Hays, C; Heck, M; Heijboer, A; Heinrich, J; Henderson, C; Herndon, M; Heuser, J; Hewamanage, S; Hidas, D; Hill, C S; Hirschbuehl, D; Hocker, A; Hou, S; Houlden, M; Hsu, S-C; Huffman, B T; Hughes, R E; Husemann, U; Huston, J; Incandela, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jayatilaka, B; Jeon, E J; Jha, M K; Jindariani, S; Johnson, W; Jones, M; Joo, K K; Jun, S Y; Jung, J E; Junk, T R; Kamon, T; Kar, D; Karchin, P E; Kato, Y; Kephart, R; Keung, J; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, H W; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Kirsch, L; Klimenko, S; Knuteson, B; Ko, B R; Kondo, K; Kong, D J; Konigsberg, J; Korytov, A; Kotwal, A V; Kreps, M; Kroll, J; Krop, D; Krumnack, N; Kruse, M; Krutelyov, V; Kubo, T; Kuhr, T; Kulkarni, N P; Kurata, M; Kusakabe, Y; Kwang, S; Laasanen, A T; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; Lecompte, T; Lee, E; Lee, H S; Lee, S W; Leone, S; Lewis, J D; Lin, C-S; Linacre, J; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, C; Liu, T; Lockyer, N S; Loginov, A; Loreti, M; Lovas, L; Lucchesi, D; Luci, C; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; Macqueen, D; Madrak, R; Maeshima, K; Makhoul, K; Maki, T; Maksimovic, P; Malde, S; Malik, S; Manca, G; Manousakis-Katsikakis, A; Margaroli, F; Marino, C; Marino, C P; Martin, A; Martin, V; Martínez, M; Martínez-Ballarín, R; Maruyama, T; Mastrandrea, P; Masubuchi, T; Mathis, M; Mattson, M E; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Menzione, A; Merkel, P; Mesropian, C; Miao, T; Miladinovic, N; Miller, R; Mills, C; Milnik, M; Mitra, A; Mitselmakher, G; Miyake, H; Moggi, N; Moon, C S; Moore, R; Morello, M J; Morlok, J; Fernandez, P Movilla; Mülmenstädt, J; Mukherjee, A; Muller, Th; Mumford, R; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Nagano, A; Naganoma, J; Nakamura, K; Nakano, I; Napier, A; Necula, V; Nett, J; Neu, C; Neubauer, M S; Neubauer, S; Nielsen, J; Nodulman, L; Norman, M; Norniella, O; Nurse, E; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Griso, S Pagan; Palencia, E; Papadimitriou, V; Papaikonomou, A; Paramonov, A A; Parks, B; Pashapour, S; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Peiffer, T; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Pianori, E; Pinera, L; Pitts, K; Plager, C; 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Wynne, S M; Xie, S; Yagil, A; Yamamoto, K; Yamaoka, J; Yang, U K; Yang, Y C; Yao, W M; Yeh, G P; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanello, L; Zanetti, A; Zhang, X; Zheng, Y; Zucchelli, S

    2009-03-13

    We report a measurement of resonance parameters of the orbitally excited (L=1) narrow B0 mesons in decays to B;{(*)+}pi;{-} using 1.7 fb;{-1} of data collected by the CDF II detector at the Fermilab Tevatron. The mass and width of the B_{2};{*0} state are measured to be m(B_{2};{*0})=5740.2_{-1.8};{+1.7}(stat)-0.8+0.9(syst) MeV/c;{2} and Gamma(B_{2};{*0})=22.7_{-3.2};{+3.8}(stat)-10.2+3.2(syst) MeV/c;{2}. The mass difference between the B_{2};{*0} and B10 states is measured to be 14.9_{-2.5};{+2.2}(stat)-1.4+1.2(syst) MeV/c;{2}, resulting in a B10 mass of 5725.3_{-2.2};{+1.6}(stat)-1.5+1.4(syst) MeV/c;{2}. This is currently the most precise measurement of the masses of these states and the first measurement of the B_{2};{*0} width.

  4. Measurement of Resonance Parameters of Orbitally Excited Narrow B0 Mesons

    NASA Astrophysics Data System (ADS)

    Aaltonen, T.; Adelman, J.; Akimoto, T.; Albrow, M. G.; González, B. Álvarez; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Apresyan, A.; Arisawa, T.; Artikov, A.; Ashmanskas, W.; Attal, A.; Aurisano, A.; Azfar, F.; Azzurri, P.; Badgett, W.; Barbaro-Galtieri, A.; Barnes, V. E.; Barnett, B. A.; Bartsch, V.; Bauer, G.; Beauchemin, P.-H.; Bedeschi, F.; Beecher, D.; Behari, S.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Beretvas, A.; Beringer, J.; Bhatti, A.; Binkley, M.; Bisello, D.; Bizjak, I.; Blair, R. E.; Blocker, C.; Blumenfeld, B.; Bocci, A.; Bodek, A.; Boisvert, V.; Bolla, G.; Bortoletto, D.; Boudreau, J.; Boveia, A.; Brau, B.; Bridgeman, A.; Brigliadori, L.; Bromberg, C.; Brubaker, E.; Budagov, J.; Budd, H. S.; Budd, S.; Burke, S.; Burkett, K.; Busetto, G.; Bussey, P.; Buzatu, A.; Byrum, K. L.; Cabrera, S.; Calancha, C.; Campanelli, M.; Campbell, M.; Canelli, F.; Canepa, A.; Carls, B.; Carlsmith, D.; Carosi, R.; Carrillo, S.; Carron, S.; Casal, B.; Casarsa, M.; Castro, A.; Catastini, P.; Cauz, D.; Cavaliere, V.; Cavalli-Sforza, M.; Cerri, A.; Cerrito, L.; Chang, S. H.; Chen, Y. C.; Chertok, M.; Chiarelli, G.; Chlachidze, G.; Chlebana, F.; Cho, K.; Chokheli, D.; Chou, J. P.; Choudalakis, G.; Chuang, S. H.; Chung, K.; Chung, W. H.; Chung, Y. S.; Chwalek, T.; Ciobanu, C. I.; Ciocci, M. A.; Clark, A.; Clark, D.; Compostella, G.; Convery, M. E.; Conway, J.; Cordelli, M.; Cortiana, G.; Cox, C. A.; Cox, D. J.; Crescioli, F.; Almenar, C. Cuenca; Cuevas, J.; Culbertson, R.; Cully, J. C.; Dagenhart, D.; Datta, M.; Davies, T.; de Barbaro, P.; de Cecco, S.; Deisher, A.; de Lorenzo, G.; Dell'Orso, M.; Deluca, C.; Demortier, L.; Deng, J.; Deninno, M.; Derwent, P. F.; di Giovanni, G. P.; Dionisi, C.; di Ruzza, B.; Dittmann, J. R.; D'Onofrio, M.; Donati, S.; Dong, P.; Donini, J.; Dorigo, T.; Dube, S.; Efron, J.; Elagin, A.; Erbacher, R.; Errede, D.; Errede, S.; Eusebi, R.; Fang, H. C.; Farrington, S.; Fedorko, W. T.; Feild, R. G.; Feindt, M.; Fernandez, J. P.; Ferrazza, C.; Field, R.; Flanagan, G.; Forrest, R.; Frank, M. J.; Franklin, M.; Freeman, J. C.; Furic, I.; Gallinaro, M.; Galyardt, J.; Garberson, F.; Garcia, J. E.; Garfinkel, A. F.; Genser, K.; Gerberich, H.; Gerdes, D.; Gessler, A.; Giagu, S.; Giakoumopoulou, V.; Giannetti, P.; Gibson, K.; Gimmell, J. L.; Ginsburg, C. M.; Giokaris, N.; Giordani, M.; Giromini, P.; Giunta, M.; Giurgiu, G.; Glagolev, V.; Glenzinski, D.; Gold, M.; Goldschmidt, N.; Golossanov, A.; Gomez, G.; Gomez-Ceballos, G.; Goncharov, M.; González, O.; Gorelov, I.; Goshaw, A. T.; Goulianos, K.; Gresele, A.; Grinstein, S.; Grosso-Pilcher, C.; Group, R. C.; Grundler, U.; da Costa, J. Guimaraes; Gunay-Unalan, Z.; Haber, C.; Hahn, K.; Hahn, S. R.; Halkiadakis, E.; Han, B.-Y.; Han, J. Y.; Happacher, F.; Hara, K.; Hare, D.; Hare, M.; Harper, S.; Harr, R. F.; Harris, R. M.; Hartz, M.; Hatakeyama, K.; Hays, C.; Heck, M.; Heijboer, A.; Heinrich, J.; Henderson, C.; Herndon, M.; Heuser, J.; Hewamanage, S.; Hidas, D.; Hill, C. S.; Hirschbuehl, D.; Hocker, A.; Hou, S.; Houlden, M.; Hsu, S.-C.; Huffman, B. T.; Hughes, R. E.; Husemann, U.; Huston, J.; Incandela, J.; Introzzi, G.; Iori, M.; Ivanov, A.; James, E.; Jayatilaka, B.; Jeon, E. J.; Jha, M. K.; Jindariani, S.; Johnson, W.; Jones, M.; Joo, K. K.; Jun, S. Y.; Jung, J. E.; Junk, T. R.; Kamon, T.; Kar, D.; Karchin, P. E.; Kato, Y.; Kephart, R.; Keung, J.; Khotilovich, V.; Kilminster, B.; Kim, D. H.; Kim, H. S.; Kim, H. W.; Kim, J. E.; Kim, M. J.; Kim, S. B.; Kim, S. H.; Kim, Y. K.; Kimura, N.; Kirsch, L.; Klimenko, S.; Knuteson, B.; Ko, B. R.; Kondo, K.; Kong, D. J.; Konigsberg, J.; Korytov, A.; Kotwal, A. V.; Kreps, M.; Kroll, J.; Krop, D.; Krumnack, N.; Kruse, M.; Krutelyov, V.; Kubo, T.; Kuhr, T.; Kulkarni, N. P.; Kurata, M.; Kusakabe, Y.; Kwang, S.; Laasanen, A. T.; Lami, S.; Lammel, S.; Lancaster, M.; Lander, R. L.; Lannon, K.; Lath, A.; Latino, G.; Lazzizzera, I.; Lecompte, T.; Lee, E.; Lee, H. S.; Lee, S. W.; Leone, S.; Lewis, J. D.; Lin, C.-S.; Linacre, J.; Lindgren, M.; Lipeles, E.; Lister, A.; Litvintsev, D. O.; Liu, C.; Liu, T.; Lockyer, N. S.; Loginov, A.; Loreti, M.; Lovas, L.; Lucchesi, D.; Luci, C.; Lueck, J.; Lujan, P.; Lukens, P.; Lungu, G.; Lyons, L.; Lys, J.; Lysak, R.; MacQueen, D.; Madrak, R.; Maeshima, K.; Makhoul, K.; Maki, T.; Maksimovic, P.; Malde, S.; Malik, S.; Manca, G.; Manousakis-Katsikakis, A.; Margaroli, F.; Marino, C.; Marino, C. P.; Martin, A.; Martin, V.; Martínez, M.; Martínez-Ballarín, R.; Maruyama, T.; Mastrandrea, P.; Masubuchi, T.; Mathis, M.; Mattson, M. E.; Mazzanti, P.; McFarland, K. S.; McIntyre, P.; McNulty, R.; Mehta, A.; Mehtala, P.; Menzione, A.; Merkel, P.; Mesropian, C.; Miao, T.; Miladinovic, N.; Miller, R.; Mills, C.; Milnik, M.; Mitra, A.; Mitselmakher, G.; Miyake, H.; Moggi, N.; Moon, C. S.; Moore, R.; Morello, M. J.; Morlok, J.; Fernandez, P. Movilla; Mülmenstädt, J.; Mukherjee, A.; Muller, Th.; Mumford, R.; Murat, P.; Mussini, M.; Nachtman, J.; Nagai, Y.; Nagano, A.; Naganoma, J.; Nakamura, K.; Nakano, I.; Napier, A.; Necula, V.; Nett, J.; Neu, C.; Neubauer, M. S.; Neubauer, S.; Nielsen, J.; Nodulman, L.; Norman, M.; Norniella, O.; Nurse, E.; Oakes, L.; Oh, S. H.; Oh, Y. D.; Oksuzian, I.; Okusawa, T.; Orava, R.; Griso, S. Pagan; Palencia, E.; Papadimitriou, V.; Papaikonomou, A.; Paramonov, A. A.; Parks, B.; Pashapour, S.; Patrick, J.; Pauletta, G.; Paulini, M.; Paus, C.; Peiffer, T.; Pellett, D. E.; Penzo, A.; Phillips, T. J.; Piacentino, G.; Pianori, E.; Pinera, L.; Pitts, K.; Plager, C.; Pondrom, L.; Poukhov, O.; Pounder, N.; Prakoshyn, F.; Pronko, A.; Proudfoot, J.; Ptohos, F.; Pueschel, E.; Punzi, G.; Pursley, J.; Rademacker, J.; Rahaman, A.; Ramakrishnan, V.; Ranjan, N.; Redondo, I.; Rekovic, V.; Renton, P.; Renz, M.; Rescigno, M.; Richter, S.; Rimondi, F.; Ristori, L.; Robson, A.; Rodrigo, T.; Rodriguez, T.; Rogers, E.; Rolli, S.; Roser, R.; Rossi, M.; Rossin, R.; Roy, P.; Ruiz, A.; Russ, J.; Rusu, V.; Safonov, A.; Sakumoto, W. K.; Saltó, O.; Santi, L.; Sarkar, S.; Sartori, L.; Sato, K.; Savoy-Navarro, A.; Schlabach, P.; Schmidt, A.; Schmidt, E. E.; Schmidt, M. A.; Schmidt, M. P.; Schmitt, M.; Schwarz, T.; Scodellaro, L.; Scribano, A.; Scuri, F.; Sedov, A.; Seidel, S.; Seiya, Y.; Semenov, A.; Sexton-Kennedy, L.; Sforza, F.; Sfyrla, A.; Shalhout, S. Z.; Shears, T.; Shepard, P. F.; Shimojima, M.; Shiraishi, S.; Shochet, M.; Shon, Y.; Shreyber, I.; Sidoti, A.; Sinervo, P.; Sisakyan, A.; Slaughter, A. J.; Slaunwhite, J.; Sliwa, K.; Smith, J. R.; Snider, F. D.; Snihur, R.; Soha, A.; Somalwar, S.; Sorin, V.; Spalding, J.; Spreitzer, T.; Squillacioti, P.; Stanitzki, M.; St. Denis, R.; Stelzer, B.; Stelzer-Chilton, O.; Stentz, D.; Strologas, J.; Strycker, G. L.; Stuart, D.; Suh, J. S.; Sukhanov, A.; Suslov, I.; Suzuki, T.; Taffard, A.; Takashima, R.; Takeuchi, Y.; Tanaka, R.; Tecchio, M.; Teng, P. K.; Terashi, K.; Thom, J.; Thompson, A. S.; Thompson, G. A.; Thomson, E.; Tipton, P.; Ttito-Guzmán, P.; Tkaczyk, S.; Toback, D.; Tokar, S.; Tollefson, K.; Tomura, T.; Tonelli, D.; Torre, S.; Torretta, D.; Totaro, P.; Tourneur, S.; Trovato, M.; Tsai, S.-Y.; Tu, Y.; Turini, N.; Ukegawa, F.; Vallecorsa, S.; van Remortel, N.; Varganov, A.; Vataga, E.; Vázquez, F.; Velev, G.; Vellidis, C.; Veszpremi, V.; Vidal, M.; Vidal, R.; Vila, I.; Vilar, R.; Vine, T.; Vogel, M.; Volobouev, I.; Volpi, G.; Wagner, P.; Wagner, R. G.; Wagner, R. L.; Wagner, W.; Wagner-Kuhr, J.; Wakisaka, T.; Wallny, R.; Wang, S. M.; Warburton, A.; Waters, D.; Weinberger, M.; Weinelt, J.; Wester, W. C., III; Whitehouse, B.; Whiteson, D.; Wicklund, A. B.; Wicklund, E.; Wilbur, S.; Williams, G.; Williams, H. H.; Wilson, P.; Winer, B. L.; Wittich, P.; Wolbers, S.; Wolfe, C.; Wright, T.; Wu, X.; Würthwein, F.; Wynne, S. M.; Xie, S.; Yagil, A.; Yamamoto, K.; Yamaoka, J.; Yang, U. K.; Yang, Y. C.; Yao, W. M.; Yeh, G. P.; Yoh, J.; Yorita, K.; Yoshida, T.; Yu, G. B.; Yu, I.; Yu, S. S.; Yun, J. C.; Zanello, L.; Zanetti, A.; Zhang, X.; Zheng, Y.; Zucchelli, S.

    2009-03-01

    We report a measurement of resonance parameters of the orbitally excited (L=1) narrow B0 mesons in decays to B(*)+π- using 1.7fb-1 of data collected by the CDF II detector at the Fermilab Tevatron. The mass and width of the B2*0 state are measured to be m(B2*0)=5740.2-1.8+1.7(stat)-0.8+0.9(syst)MeV/c2 and Γ(B2*0)=22.7-3.2+3.8(stat)-10.2+3.2(syst)MeV/c2. The mass difference between the B2*0 and B10 states is measured to be 14.9-2.5+2.2(stat)-1.4+1.2(syst)MeV/c2, resulting in a B10 mass of 5725.3-2.2+1.6(stat)-1.5+1.4(syst)MeV/c2. This is currently the most precise measurement of the masses of these states and the first measurement of the B2*0 width.

  5. Blade resonance parameter identification based on tip-timing method without the once-per revolution sensor

    NASA Astrophysics Data System (ADS)

    Guo, Haotian; Duan, Fajie; Zhang, Jilong

    2016-01-01

    Blade tip-timing is the most effective method for blade vibration online measurement of turbomachinery. In this article a synchronous resonance vibration measurement method of blade based on tip-timing is presented. This method requires no once-per revolution sensor which makes it more generally applicable in the condition where this sensor is difficult to install, especially for the high-pressure rotors of dual-rotor engines. Only three casing mounted probes are required to identify the engine order, amplitude, natural frequency and the damping coefficient of the blade. A method is developed to identify the blade which a tip-timing data belongs to without once-per revolution sensor. Theoretical analyses of resonance parameter measurement are presented. Theoretic error of the method is investigated and corrected. Experiments are conducted and the results indicate that blade resonance parameter identification is achieved without once-per revolution sensor.

  6. Blind Source Parameters for Performance Evaluation of Despeckling Filters

    PubMed Central

    Biradar, Nagashettappa; Dewal, M. L.; Rohit, ManojKumar; Gowre, Sanjaykumar; Gundge, Yogesh

    2016-01-01

    The speckle noise is inherent to transthoracic echocardiographic images. A standard noise-free reference echocardiographic image does not exist. The evaluation of filters based on the traditional parameters such as peak signal-to-noise ratio, mean square error, and structural similarity index may not reflect the true filter performance on echocardiographic images. Therefore, the performance of despeckling can be evaluated using blind assessment metrics like the speckle suppression index, speckle suppression and mean preservation index (SMPI), and beta metric. The need for noise-free reference image is overcome using these three parameters. This paper presents a comprehensive analysis and evaluation of eleven types of despeckling filters for echocardiographic images in terms of blind and traditional performance parameters along with clinical validation. The noise is effectively suppressed using the logarithmic neighborhood shrinkage (NeighShrink) embedded with Stein's unbiased risk estimation (SURE). The SMPI is three times more effective compared to the wavelet based generalized likelihood estimation approach. The quantitative evaluation and clinical validation reveal that the filters such as the nonlocal mean, posterior sampling based Bayesian estimation, hybrid median, and probabilistic patch based filters are acceptable whereas median, anisotropic diffusion, fuzzy, and Ripplet nonlinear approximation filters have limited applications for echocardiographic images. PMID:27298618

  7. A laboratory study to estimate pore geometric parameters of sandstones using complex conductivity and nuclear magnetic resonance for permeability prediction

    NASA Astrophysics Data System (ADS)

    Osterman, Gordon; Keating, Kristina; Binley, Andrew; Slater, Lee

    2016-06-01

    We estimate parameters from the Katz and Thompson permeability model using laboratory complex electrical conductivity (CC) and nuclear magnetic resonance (NMR) data to build permeability models parameterized with geophysical measurements. We use the Katz and Thompson model based on the characteristic hydraulic length scale, determined from mercury injection capillary pressure estimates of pore throat size, and the intrinsic formation factor, determined from multisalinity conductivity measurements, for this purpose. Two new permeability models are tested, one based on CC data and another that incorporates CC and NMR data. From measurements made on forty-five sandstone cores collected from fifteen different formations, we evaluate how well the CC relaxation time and the NMR transverse relaxation times compare to the characteristic hydraulic length scale and how well the formation factor estimated from CC parameters compares to the intrinsic formation factor. We find: (1) the NMR transverse relaxation time models the characteristic hydraulic length scale more accurately than the CC relaxation time (R2 of 0.69 and 0.33 and normalized root mean square errors (NRMSE) of 0.16 and 0.21, respectively); (2) the CC estimated formation factor is well correlated with the intrinsic formation factor (NRMSE=0.23). We demonstrate that that permeability estimates from the joint-NMR-CC model (NRMSE=0.13) compare favorably to estimates from the Katz and Thompson model (NRMSE=0.074). This model advances the capability of the Katz and Thompson model by employing parameters measureable in the field giving it the potential to more accurately estimate permeability using geophysical measurements than are currently possible.

  8. Quick evaluation of kinase inhibitors by surface plasmon resonance using single-site specifically biotinylated kinases.

    PubMed

    Kitagawa, Daisuke; Gouda, Masaki; Kirii, Yasuyuki

    2014-03-01

    In evaluating kinase inhibitors, kinetic parameters such as association/dissociation rate constants are valuable information, as are equilibrium parameters KD and IC50 values. Surface plasmon resonance (SPR) is a powerful technique to investigate these parameters. However, results are often complicated because of impaired conformations by inappropriate conditions required for protein immobilization and/or heterogeneity of the orientation of immobilization. In addition, conventional SPR experiments are generally time-consuming. Here we introduce the use of single-site specifically biotinylated kinases combined with a multichannel SPR device to improve such problems. Kinetic parameters of four compounds-staurosporine, dasatinib, sunitinib, and lapatinib-against six kinases were determined by the ProteOn XPR36 system. The very slow off-rate of lapatinib from the epidermal growth factor receptor and dasatinib from Bruton's tyrosine kinase and colony stimulating factor 1 receptor (CSF1R) were confirmed. Furthermore, IC50 values were determined by an activity-based assay. Evaluating both physicochemical and biochemical properties would help to understand the detailed character of the compound.

  9. Evaluating Iron Content and Tissue Microstructure with Off-Resonance Saturation MRI

    NASA Astrophysics Data System (ADS)

    Fahmy, Sherif R.

    We present three magnetic resonance imaging (MRI) studies, each focused on applying off-resonance saturation (ORS) imaging to a different context or application. Particularly, we are interested in using ORS to evaluate the uptake of superparamagnetic MRI contrast agents in biological tissue, and to evaluate endogenous iron content. This relies on ORS being applied at low off-resonance frequency offsets where most of the negative contrast is due to signal loss from direct saturation of the water content of the sample. Additionally, we wish to combine this information with magnetization transfer contrast, which is obtained by applying ORS at offsets that are far from the resonance frequency, where magnetization transfer (MT) becomes the dominant effect rather than direct saturation (DS). In the first study, we observed the uptake of ultra-small superparamagnetic iron oxide (USPIO) nanoparticles in a simple model system by imaging the uptake in healthy murine liver in vivo, and by testing different metrics to quantify the uptake. Through this process, we discovered an approach that provides high sensitivity and specificity in low-signal scenarios. In the second study, we evaluated image contrast between brain regions in healthy human adults, and related these to the expected iron content in different regions based on age. Images were evaluated based on different MRI contrast mechanisms including quantitative transverse relaxation rates, as well as parameters obtained from ORS imaging. We also performed a field inhomogeneity adjustment on low-offset ORS data using the information obtained from the coarsely sampled ORS spectrum, and this was sufficient to correct for the inhomogeneities. In the third study, we used transverse relaxation, DS - which is strongly dependent on iron content, and MT contrast, in order to classify ex vivo brain samples having Alzheimer's disease pathology and normal controls, and were able to find strong classifiers. The three studies helped

  10. Performance Evaluation and Parameter Identification on DROID III

    NASA Technical Reports Server (NTRS)

    Plumb, Julianna J.

    2011-01-01

    The DROID III project consisted of two main parts. The former, performance evaluation, focused on the performance characteristics of the aircraft such as lift to drag ratio, thrust required for level flight, and rate of climb. The latter, parameter identification, focused on finding the aerodynamic coefficients for the aircraft using a system that creates a mathematical model to match the flight data of doublet maneuvers and the aircraft s response. Both portions of the project called for flight testing and that data is now available on account of this project. The conclusion of the project is that the performance evaluation data is well-within desired standards but could be improved with a thrust model, and that parameter identification is still in need of more data processing but seems to produce reasonable results thus far.

  11. High-performance lighting evaluated by photobiological parameters.

    PubMed

    Rebec, Katja Malovrh; Gunde, Marta Klanjšek

    2014-08-10

    The human reception of light includes image-forming and non-image-forming effects which are triggered by spectral distribution and intensity of light. Ideal lighting is similar to daylight, which could be evaluated by spectral or chromaticity match. LED-based and CFL-based lighting were analyzed here, proposed according to spectral and chromaticity match, respectively. The photobiological effects were expressed by effectiveness for blue light hazard, cirtopic activity, and photopic vision. Good spectral match provides light with more similar effects to those obtained by the chromaticity match. The new parameters are useful for better evaluation of complex human responses caused by lighting.

  12. Critical evaluation of resonance integrals for activation analysis

    SciTech Connect

    Holden, N.E.

    1993-08-01

    Resonance Integrals are used to calculate neutron reaction rates in the epithermal neutron energy region. Values for the standard capture reactions in gold, cobalt and manganese have been reviewed and recommended resonance integrals are presented. Recommended values for various reactions are presented relative to the capture standards.

  13. Neutron Resonance Parameters of 55Mn from Reich-Moore Analysis of Recent Experimental Neutron Transmission and Capture Cross Sections

    SciTech Connect

    Derrien, Herve; Leal, Luiz C; Larson, Nancy M; Guber, Klaus H; Wiarda, Dorothea; Arbanas, Goran

    2008-01-01

    High-resolution neutron capture cross section measurements of 55Mn were recently performed at GELINA by Schillebeeckx et al. (2005) and at ORELA by Guber et al. (2007). The analysis of the experimental data was performed with the computer code SAMMY using the Bayesian approach in the resonance parameters representation of the cross sections. The neutron transmission data taken in 1988 by Harvey et al. (2007) and not analyzed before were added to the SAMMY experimental data base. More than 95% of the s-wave resonances and more than 85% of the p-wave resonances were identified in the energy range up to 125 keV, leading to the neutron strength functions S0 = (3.90 0.78) x 10-4 and S1 = (0.45 0.08) x 10-4. About 25% of the d-wave resonances were identified with a possible strength function of S2 = 1.0 x 10-4. The capture cross section calculated at 0.0253 eV is 13.27 b, and the capture resonance integral is 13.52 0.30 b. In the energy range 15 to 120 keV, the average capture cross section is 12% lower than Lerigoleur value and 25% smaller than Macklin value. GELINA and ORELA experimental capture cross sections show a background cross section not described by the Reich-Moore resonance parameters. Part of this background could be due to a direct capture component and/or to the missing d-wave resonances. The uncertainty of 10% on the average capture cross section above 20 keV is mainly due to the inaccuracy in the calculation of the background components.

  14. Triangular Ring Resonator: Direct Measurement of the Parity-Odd Parameters of the Photon Sector of SME

    NASA Astrophysics Data System (ADS)

    Exirifard, Qasem

    2014-03-01

    We introduce the Triangular Ring (TR) resonator. We show that the difference between the clockwise and anti-clockwise resonant frequencies of a vacuum TR resonator is sensitive to the birefringence parity-odd parameters of the photon's sector of the minimal Standard Model Extension (mSME): the Standard Model plus all the perturbative parameters encoding the break of the Lorentz symmetry. We report that utilizing the current technology allows for direct measurement of these parameters with a sensitivity of the parity-even ones and improves the best current resonator bounds by couple of orders of magnitudes. We note that, designing an optical table that rotates perpendicular to the gravitational equipotential surface (geoid) allows for direct measurement of the constancy of the light speed at the vicinity of the earth in all directions, in particular, perpendicular to the geoid. If this table could achieve the precision of the ordinary tables, then it would improve the GPS bounds on the constancy of the light speed perpendicular to geoid by about eight orders of magnitude.

  15. Analytical modeling of Schumann resonance and ELF propagation parameters on Mars with a multi-layered ground

    NASA Astrophysics Data System (ADS)

    Kozakiewicz, Joanna; Kulak, Andrzej; Mlynarczyk, Janusz

    2015-11-01

    Two electrically conductive planetary spheres, the ionosphere and the ground, form a spherical waveguide. Within such a planetary cavity a phenomenon called Schumann resonance (SR) can occur. It is a resonance of extremely low frequency (ELF) electromagnetic waves. The resonance parameters are strongly related to the electromagnetic properties of the cavity. On Mars, as there is no liquid water at the planetary surface, the ground has a low conductivity. In such a situation, ELF waves penetrate into the planetary subsurface up to many kilometers depth. To examine the influence of low-conductivity grounds on ELF propagation, we have introduced a recently developed analytical method, which enables to estimate the propagation parameters and explicate their dependence of the ground properties. Since the presented model is fully analytical, it is computationally efficient and can be very useful in finding inverse solutions. To demonstrate the potential of the method, we present the relationship between individual ground properties and the parameters of Schumann resonance. The obtained results indicate that Martian exploration performed by one ELF station located at the planetary surface can reveal, along with the properties of the ionosphere, the existence of liquid water under the Martian surface.

  16. Nuclear magnetic resonance parameters of atomic xenon dissolved in Gay-Berne model liquid crystal.

    PubMed

    Lintuvuori, Juho; Straka, Michal; Vaara, Juha

    2007-03-01

    We present constant-pressure Monte Carlo simulations of nuclear magnetic resonance (NMR) spectral parameters, nuclear magnetic shielding relative to the free atom as well as nuclear quadrupole coupling, for atomic xenon dissolved in a model thermotropic liquid crystal. The solvent is described by Gay-Berne (GB) molecules with parametrization kappa=4.4, kappa{'}=20.0 , and mu=nu=1 . The reduced pressure of P{*}=2.0 is used. Previous simulations of a pure GB system with this parametrization have shown that upon lowering the temperature, the model exhibits isotropic, nematic, smectic- A , and smectic- B /molecular crystal phases. We introduce spherical xenon solutes and adjust the energy and length scales of the GB-Xe interaction to those of the GB-GB interaction. This is done through first principles quantum chemical calculations carried out for a dimer of model mesogens as well as the mesogen-xenon complex. We preparametrize quantum chemically the Xe nuclear shielding and quadrupole coupling tensors when interacting with the model mesogen, and use the parametrization in a pairwise additive fashion in the analysis of the simulation. We present the temperature evolution of {129/131}Xe shielding and 131Xe quadrupole coupling in the different phases of the GB model. From the simulations, separate isotropic and anisotropic contributions to the experimentally available total shielding can be obtained. At the experimentally relevant concentration, the presence of the xenon atoms does not significantly affect the phase behavior as compared to the pure GB model. The simulations reproduce many of the characteristic experimental features of Xe NMR in real thermotropic LCs: Discontinuity in the value or trends of the shielding and quadrupole coupling at the nematic-isotropic and smectic-A-nematic phase transitions, nonlinear shift evolution in the nematic phase reflecting the behavior of the orientational order parameter, and decreasing shift in the smectic-A phase. The last

  17. Neutron Cross Section Processing Methods for Improved Integral Benchmarking of Unresolved Resonance Region Evaluations

    NASA Astrophysics Data System (ADS)

    Walsh, Jonathan A.; Forget, Benoit; Smith, Kord S.; Brown, Forrest B.

    2016-03-01

    In this work we describe the development and application of computational methods for processing neutron cross section data in the unresolved resonance region (URR). These methods are integrated with a continuous-energy Monte Carlo neutron transport code, thereby enabling their use in high-fidelity analyses. Enhanced understanding of the effects of URR evaluation representations on calculated results is then obtained through utilization of the methods in Monte Carlo integral benchmark simulations of fast spectrum critical assemblies. First, we present a so-called on-the-fly (OTF) method for calculating and Doppler broadening URR cross sections. This method proceeds directly from ENDF-6 average unresolved resonance parameters and, thus, eliminates any need for a probability table generation pre-processing step in which tables are constructed at several energies for all desired temperatures. Significant memory reduction may be realized with the OTF method relative to a probability table treatment if many temperatures are needed. Next, we examine the effects of using a multi-level resonance formalism for resonance reconstruction in the URR. A comparison of results obtained by using the same stochastically-generated realization of resonance parameters in both the single-level Breit-Wigner (SLBW) and multi-level Breit-Wigner (MLBW) formalisms allows for the quantification of level-level interference effects on integrated tallies such as keff and energy group reaction rates. Though, as is well-known, cross section values at any given incident energy may differ significantly between single-level and multi-level formulations, the observed effects on integral results are minimal in this investigation. Finally, we demonstrate the calculation of true expected values, and the statistical spread of those values, through independent Monte Carlo simulations, each using an independent realization of URR cross section structure throughout. It is observed that both probability table

  18. Nuclear Magnetic Resonance Nondestructive Evaluation of Composite Materials

    DTIC Science & Technology

    1990-04-09

    Pat. Appl. EP 26265, 8 Apr 1981, 13 pp. (1981). 9. A. N. Garroway , J. Baum, M. G. Munowitz, and A. Pines, NMR Imaging in Solids by Multiple-Quantum...Resonance, J. Magn. Reson. 60(2), 337-41 (1984). 10. J. Baum, A. N. Garroway , M. Munowitz, and A. Pines, Multiple-Quantum NMR in Solids: Application to... Garroway , NMR Images of Solids, J. Magn. Reson. 66(3), 530-5 (1986). 28. J. B. Miller and A. N. Garroway , Removal of Static Field Inhomogeneity and

  19. Quantitative evaluation on the performance and feature enhancement of stochastic resonance for bearing fault diagnosis

    NASA Astrophysics Data System (ADS)

    Li, Guoying; Li, Jimeng; Wang, Shibin; Chen, Xuefeng

    2016-12-01

    Stochastic resonance (SR) has been widely applied in the field of weak signal detection by virtue of its characteristic of utilizing noise to amplify useful signal instead of eliminating noise in nonlinear dynamical systems. How to quantitatively evaluate the performance of SR, including the enhancement effect and the degree of waveform distortion, and how to accurately extract signal amplitude have become two important issues in the research on SR. In this paper, the signal-to-noise ratio (SNR) of the main component to the residual in the SR output is constructed to quantitatively measure the enhancement effect of the SR method. And two indices are constructed to quantitatively measure the degree of waveform distortion of the SR output, including the correlation coefficient between the main component in the SR output and the original signal, and the zero-crossing ratio. These quantitative indices are combined to provide a comprehensive quantitative index for adaptive parameter selection of the SR method, and eventually the adaptive SR method can be effective in enhancing the weak component hidden in the original signal. Fast Fourier Transform and Fourier Transform (FFT+FT) spectrum correction technology can extract the signal amplitude from the original signal and effectively reduce the difficulty of extracting signal amplitude from the distorted resonance output. The application in vibration analysis for bearing fault diagnosis verifies that the proposed quantitative evaluation method for adaptive SR can effectively detect weak fault feature of the vibration signal during the incipient stage of bearing fault.

  20. Vibration evaluation and parameter optimization of hydraulic thruster

    NASA Astrophysics Data System (ADS)

    Peng, Yong; Zhang, Haokun

    2017-01-01

    Two difficult problems which are drilling string vibration and drilling pressure control exist in the process of drilling large displacement horizontal well. Using hydraulic thruster can not only improve the mechanical drilling speed and increase the horizontal section of footage displacement but also obtain better drill string dynamic characteristics and reduce vibration of drilling tool and prolong the life of the bottom hole assembly. By using the spring-damping model of drill string, the dynamic response of the different excitation of the drill bit is analyzed, so as to evaluate the effect of vibration reduction of hydraulic thruster. Use the three factors four levels orthogonal test method to optimize the key design parameters of hydraulic thruster. The analysis shows that the different drilling mud density should be used in the hydraulic thruster with different key parameters, in order to display its superiority.

  1. TRITOX: a multiple parameter evaluation of tritium toxicity

    SciTech Connect

    Carsten, A.L.

    1982-01-01

    The increased use of nuclear reactors for power generation will lead to the introduction of tritium into the environment. The need for assessing possible immediate and long-term effects of exposure to this tritium led to the development of a broad program directed towards evaluating the possible somatic and genetic effects of continuous exposure to tritiated water (HTO). Among the parameters measured are the genetic, cytogenetic, reproductive efficiency, growth, nonspecific lifetime shortening, bone marrow cellularity and stem cell content, relative biological effectiveness as compared to /sup 137/Cesium gamma exposure, and related biochemical and microdosimetric evaluations. These parameters have been evaluated on animals maintained on HTO at 10 to 100 times the maximum permissible concentration (0.03 - 3.0 ..mu..Ci/ml) for HTO. Dominant lethal mutations, chromosome aberrations in regenerating liver, increased sister chromatid exchanges in bone marrow and reduction in bone marrow stem cell content have been observed at the higher concentrations. The relative biological effectiveness for HTO ingestion as compared to external /sup 137/Cesium gamma exposures has been found to be between 1 and 2.

  2. Far-field beam quality evaluation of high-power unstable resonators TEA CO2 Laser

    NASA Astrophysics Data System (ADS)

    Guo, Ruhai; Chen, Ning; Shi, Kui; Wang, Bing

    2013-05-01

    High average power pulsed TEA CO2 lasers have many important applications, such as laser manufacturing, military applications, but there rarely have reports about the theoretical and experimental studies on the virtual confocus resonator of pulsed TEA CO2 laser, especially its far field optical quality. Based on the real date of the unstable resonator modified by the stable resonator of high power TEA CO2, three common theoretical evaluations and analyzes were conducted and compared with the measured results of far field light intensity distribution with 2 kW designed unstable resonator laser with the block ratio is ɛ=0.404. The results show that the unstable resonator can obtain near diffraction limitation and high optical quality beam. The β factor is smaller than 4 times than the stable resonator. Furthermore, the smaller block factor can make higher power in bucket for the unstable resonator. The comprehensive prediction and evaluation of designed unstable resonator need to synthetically use these three theoretical methods of the evaluations. The simulation results, with considering the optical aberration, heat distortion and atmospheric effect, agree well with the real recording image by the infrared imaging system in the distance of 300m. The research of this paper has very important reference value for evaluating the tactical effectiveness and optimization design of high power TEA CO2 laser system with different unstable resonators.

  3. Preoperative Magnetic Resonance Imaging Evaluation in Patients with Adolescent Idiopathic Scoliosis

    PubMed Central

    Lee, Choon Sung; Kim, Nam Heun; Noh, Hyun Min; Lee, Mi Young; Yoon, So Jung; Lee, Dong-Ho

    2017-01-01

    Study Design Retrospective case series. Purpose The purpose of this study was to examine the incidence of neural axis abnormalities and the relevant risk factors in patients with adolescent idiopathic scoliosis (AIS). Overview of Literature The use of preoperative magnetic resonance imaging (MRI) to assess the whole spine in patients with idiopathic scoliosis is controversial, and indications for such MRI evaluations have not been definitively established. However, we routinely use whole-spine MRI in patients with scoliosis who are scheduled to undergo surgical correction. Methods A total of 378 consecutive patients with presumed AIS who were admitted for spinal surgery were examined for neural axis abnormalities using MRI. To differentiate patients with normal and abnormal MRI findings, the following clinical parameters were evaluated: age, sex, menarcheal status, rotation angle (using a scoliometer), coronal balance, shoulder height difference, and low back pain. We radiographically evaluated curve type, thoracic or thoracolumbar curve direction, curve magnitude and flexibility, apical vertebral rotation, curve length, coronal balance, sagittal balance, shoulder height difference, thoracic kyphosis, and the Risser sign. Results Neural axis abnormalities were detected in 24 patients (6.3%). Abnormal MRI findings were significantly more common in males than in females and were associated with increased thoracic kyphosis. However, there were no significant differences in terms of the other measured parameters. Conclusions Among the patients with presumed AIS who received preoperative whole-spine MRI, 6.3% had neural axis abnormalities. Males and patients with increased thoracic kyphosis were at a higher risk. PMID:28243367

  4. Evaluation of haematological, biochemical and histopathological parameters of transgenic rabbits.

    PubMed

    Jurcik, R; Suvegova, K; Hanusova, E; Massanyi, P; Ryban, L; Chrenek, P

    2007-11-01

    The aim of our study was to compare the hFVIII mRNA expression in different organs, pathological changes and selected haematological and biochemical blood parameters between transgenic and non-transgenic rabbits from F3 generation. Selected physiological parameters of 3- to 4-month-old transgenic rabbits from F3 generation carrying human factor VIII gene (hFVIII) were analysed and compared with those of non-transgenic ones. Before slaughtering, the blood for haematological and biochemical analysis was taken from the central ear artery. Pathological and histological examination of vital organs and RT-PCR analysis of several tissue organs of transgenic and non-transgenic animals were performed after slaughtering. Except for the mammary gland tissue, slight hfVIII mRNA expression in the spleen, lung and brain and none expression in the liver, kidney, skeletal muscle and heart of rabbits were recorded. pathological examination of vital organs showed some pathological changes in both transgenic and non-transgenic rabbits which were confirmed by histological qualitative evaluations. Statistically significant lower values of blood haemoglobin in blood of transgenic (11.86+/-0.86) animals compared with non-transgenic (12.41+/-1.02, P<0.05) ones and lower parameters of HCT (39.22+/-2.44 versus 40.89+/-2.26, P<0.01) in blood of transgenic rabbits were observed. Parameters of WBC, RBC and PLT showed no significant differences between the analysed groups. All biochemical serum parameters of transgenic rabbits were higher in comparison with non-transgenic ones. Significant differences were found in the concentration of the urea, AST and GMT between transgenic and non-transgenic animals (P<0.001) and in the total protein content, the difference was significant at P<0.05. In conclusion, our results showed that no considerable impact on the general health was found in transgenic rabbits.

  5. Evaluated 182,183,184,186W Neutron Cross Sections and Covariances in the Resolved Resonance Region

    SciTech Connect

    Pigni, Marco T; Leal, Luiz C

    2015-01-01

    Oak Ridge National Laboratory (ORNL) has recently completed the resonance parameter evaluation of four tungsten isotopes, i.e., 182,183,184,186W, in the neutron energy range of thermal up to several keV. This nuclear data work was performed with support from the US Nuclear Criticality Safety Program (NCSP) in an effort to provide improved tungsten cross section and covariance data for criticality safety analyses. The evaluation methodology uses the Reich-Moore approximation of the R-matrix formalism of the code SAMMY to fit high-resolution measurements performed in 2010 and 2012 at the Geel linear accelerator facility (GELINA), as well as other experimental data sets on natural tungsten available in the EXFOR library. In the analyzed energy range, this work nearly doubles the resolved resonance region (RRR) present in the latest US nuclear data library ENDF/B-VII.1. In view of the interest in tungsten for distinct types of nuclear applications and the relatively homogeneous distribution of the isotopic tungsten—namely, 182W(26.5%), 183W(14.31%), 184W(30.64%), and 186W(28.43%) - the completion of these four evaluations represents a significant contribution to the improvement of the ENDF library. This paper presents an overview of the evaluated resonance parameters and related covariances for total and capture cross sections on the four tungsten isotopes.

  6. A high-fidelity Monte Carlo evaluation of CANDU-6 safety parameters

    SciTech Connect

    Kim, Y.; Hartanto, D.

    2012-07-01

    Important safety parameters such as the fuel temperature coefficient (FTC) and the power coefficient of reactivity (PCR) of the CANDU-6 (CANada Deuterium Uranium) reactor have been evaluated by using a modified MCNPX code. For accurate analysis of the parameters, the DBRC (Doppler Broadening Rejection Correction) scheme was implemented in MCNPX in order to account for the thermal motion of the heavy uranium nucleus in the neutron-U scattering reactions. In this work, a standard fuel lattice has been modeled and the fuel is depleted by using the MCNPX and the FTC value is evaluated for several burnup points including the mid-burnup representing a near-equilibrium core. The Doppler effect has been evaluated by using several cross section libraries such as ENDF/B-VI, ENDF/B-VII, JEFF, JENDLE. The PCR value is also evaluated at mid-burnup conditions to characterize safety features of equilibrium CANDU-6 reactor. To improve the reliability of the Monte Carlo calculations, huge number of neutron histories are considered in this work and the standard deviation of the k-inf values is only 0.5{approx}1 pcm. It has been found that the FTC is significantly enhanced by accounting for the Doppler broadening of scattering resonance and the PCR are clearly improved. (authors)

  7. Calculation of supercritical Dirac resonance parameters for heavy-ion systems from a coupled-differential-equation approach

    SciTech Connect

    Marsman, A.; Horbatsch, M.

    2011-09-15

    Previous work [E. Ackad and M. Horbatsch, Phys. Rev. A 78, 062711 (2008)] on supercritical Dirac resonance parameters from extrapolated analytic continuation, obtained with a Fourier grid method, is generalized by numerically solving the coupled Dirac radial equations to a high precision. The equations, which contain the multipole decomposition of the two-center potential, are augmented by a complex absorbing potential and truncated at various orders in the partial wave expansion to demonstrate convergence of the resonance parameters in the limit of vanishing absorber. The convergence of the partial-wave spinor and of the multipole potential expansions is demonstrated in the supercritical regime. The comparison of critical distances with literature values shows that the work provides benchmark results for future two-center calculations without multipole expansion.

  8. Dependence of nuclear quadrupole resonance transitions on the electric field gradient asymmetry parameter for nuclides with half-integer spins

    SciTech Connect

    Cho, Herman

    2016-02-28

    Allowed transition energies and eigenstate expansions have been calculated and tabulated in numerical form as functions of the electric field gradient asymmetry parameter for the zero field Hamiltonian of quadrupolar nuclides with I = 3/2,5/2,7/2, and 9/2. These results are essential to interpret nuclear quadrupole resonance (NQR) spectra and extract accurate values of the electric field gradient tensors. Furthermore, applications of NQR methods to studies of electronic structure in heavy element systems are proposed.

  9. Dependence of nuclear quadrupole resonance transitions on the electric field gradient asymmetry parameter for nuclides with half-integer spins

    NASA Astrophysics Data System (ADS)

    Cho, Herman

    2016-09-01

    Allowed transition energies and eigenstate expansions have been calculated and tabulated in numerical form as functions of the electric field gradient asymmetry parameter for the zero field Hamiltonian of quadrupolar nuclides with I = 3 / 2 , 5 / 2 , 7 / 2, and 9 / 2. These results are essential to interpret nuclear quadrupole resonance (NQR) spectra and extract accurate values of the electric field gradient tensors. Applications of NQR methods to studies of electronic structure in heavy element systems are proposed.

  10. Neutron Resonance Parameters of 238U and the Calculated Cross Sections from the Reich-Moore Analysis of Experimental Data in the Neutron Energy Range from 0 keV to 20 keV

    SciTech Connect

    Derrien, H

    2005-12-05

    The neutron resonance parameters of {sup 238}U were obtained from a SAMMY analysis of high-resolution neutron transmission measurements and high-resolution capture cross section measurements performed at the Oak Ridge Electron Linear Accelerator (ORELA) in the years 1970-1990, and from more recent transmission and capture cross section measurements performed at the Geel Linear Accelerator (GELINA). Compared with previous evaluations, the energy range for this resonance analysis was extended from 10 to 20 keV, taking advantage of the high resolution of the most recent ORELA transmission measurements. The experimental database and the method of analysis are described in this report. The neutron transmissions and the capture cross sections calculated with the resonance parameters are compared with the experimental data. A description is given of the statistical properties of the resonance parameters and of the recommended values of the average parameters. The new evaluation results in a slight decrease of the effective capture resonance integral and improves the prediction of integral thermal benchmarks by 70 pcm to 200 pcm.

  11. Parameters of Instrumental Swallowing Evaluations: Describing a Diagnostic Dilemma.

    PubMed

    Pisegna, Jessica M; Langmore, Susan E

    2016-06-01

    The aim of this study was to compare selected parameters of two swallow evaluations: fiberoptic endoscopic evaluation of swallowing (FEES) and the modified barium swallow (MBS) study. This was a cross-sectional, descriptive study. Fifty-five clinicians were asked to watch video recordings of swallow evaluations of 2 patients that were done using fluoroscopy and endoscopy simultaneously. In a randomized order, clinicians viewed 4 edited videos from simultaneous evaluations: the FEES and MBS videos of patient 1 and 2 each taking one swallow of 5 mL applesauce. Clinicians filled out a questionnaire that asked (1) which anatomical sites they could visualize on each video, (2) where they saw pharyngeal residue after a swallow, (3) their overall clinical impression of the pharyngeal residue, and (4) their opinions of the evaluation styles. Clinicians reported a significant difference in the visualization of anatomical sites, 11 of the 15 sites were reported as better-visualized on the FEES than on the MBS video (p < 0.05). Clinicians also rated residue to be present in more locations on the FEES than on the MBS. Clinicians' overall impressions of the severity of residue on the same exact swallow were significantly different depending on the evaluation type (FEES vs. MBS for patient 1 χ(2) = 20.05, p < 0.0001; patient 2 χ(2) = 7.52, p = 0.006), with FEES videos rated more severely. FEES advantages were: more visualization of pharyngeal and laryngeal swallowing anatomy and residue. However, as a result, clinicians provided more severe impressions of residue amount on FEES. On one hand, this suggests that FEES is a more sensitive tool than MBS studies, but on the other hand, clinicians might provide more severe interpretations on FEES.

  12. Evaluation of Handwriting Movement Kinematics: From an Ecological to a Magnetic Resonance Environment

    PubMed Central

    Bisio, Ambra; Pedullà, Ludovico; Bonzano, Laura; Ruggeri, Piero; Brichetto, Giampaolo; Bove, Marco

    2016-01-01

    Writing is a means of communication which requires complex motor, perceptual, and cognitive skills. If one of these abilities gets lost following traumatic events or due to neurological diseases, handwriting could deteriorate. Occupational therapy practitioners provide rehabilitation services for people with impaired handwriting. However, to determine the effectiveness of handwriting interventions no studies assessed whether the proposed treatments improved the kinematics of writing movement or had an effect at the level of the central nervous system. There is need to find new quantitative methodologies able to describe the behavioral and the neural outcomes of the rehabilitative interventions for handwriting. In the present study we proposed a combined approach that allowed evaluating the kinematic parameters of handwriting movements, acquired by means of a magnetic resonance-compatible tablet, and their neural correlates obtained simultaneously from a functional magnetic resonance imaging examination. Results showed that the system was reliable in term of reproducibility of the kinematic data during a test/re-test procedure. Further, despite the modifications with respect to an ecological writing movement condition, the kinematic parameters acquired inside the MR-environment were descriptive of individuals’ movement features. At last, the imaging protocol succeeded to show the activation of the cerebral regions associated with the production of writing movement in healthy people. From these findings, this methodology seems to be promising to evaluate the handwriting movement deficits and the potential alterations in the neural activity in those individuals who have handwriting difficulties. Finally, it would provide a mean to quantitatively assess the effect of a rehabilitative treatment. PMID:27746727

  13. Comprehensive evaluation of fracture parameters by dual laterolog data

    NASA Astrophysics Data System (ADS)

    Saboorian-Jooybari, Hadi; Dejam, Morteza; Chen, Zhangxin; Pourafshary, Peyman

    2016-08-01

    Reservoir quality and productivity of tight formations depend heavily on the degree of fracture development. In fact, hard and dense carbonate formations may not be considered as net pay without the presence of fractures that convey fluids towards the wellbore. The evaluation of fractures is key to effective reservoir characterization for purposes like well drilling and completion as well as development and simulation of fractured reservoirs. Although imaging technologies such as Formation Micro-Scanners and Imagers (FMS and FMI) provide useful information about fracture properties (i.e., dip angle, porosity, aperture, and permeability), they are very expensive and may not be available in all wells. In this work, fracture parameters are estimated using conventional dual laterolog (DLL) resistivity which includes shallow (LLS) and deep (LLD) responses. This technique is based on electrical resistivity anomalies resulting from the separation of shallow and deep laterolog curves. Fracture parameters that can be calculated by DLL include dip angle, aperture, porosity, permeability, and cementation factor. The accuracy of the parameters calculated using DLL data is validated by the results of FMI in a well in one of the Iranian fractured reservoirs. Contrary to the image logs, the conventional DLL is run routinely in all drilled wells. Therefore, if a reservoir has limited and insufficient data of image logs, as it is often the case, the DLLs can be used as a reliable replacement in the construction of fracture models. Furthermore, DLL has an advantage of deeper evaluation of fractures in comparison with the immediate borehole investigation of image logs.

  14. Evaluation of the IRT Parameter Invariance Property for the MCAT.

    ERIC Educational Resources Information Center

    Kelkar, Vinaya; Wightman, Linda F.; Luecht, Richard M.

    The purpose of this study was to investigate the viability of the property of parameter invariance for the one-parameter (1P), two-parameter (2P), and three-parameter (3P) item response theory (IRT) models for the Medical College Admissions Tests (MCAT). Invariance of item parameters across different gender, ethnic, and language groups and the…

  15. Surface Plasmon Resonance Evaluation of Colloidal Metal Aerogel Filters

    NASA Technical Reports Server (NTRS)

    Smith, David D.; Sibille, Laurent; Cronise, Raymond J.; Noever, David A.

    1997-01-01

    Surface plasmon resonance imaging has in the past been applied to the characterization of thin films. In this study we apply the surface plasmon technique not to determine macroscopic spatial variations but rather to determine average microscopic information. Specifically, we deduce the dielectric properties of the surrounding gel matrix and information concerning the dynamics of the gelation process from the visible absorption characteristics of colloidal metal nanoparticles contained in aerogel pores. We have fabricated aerogels containing gold and silver nanoparticles. Because the dielectric constant of the metal particles is linked to that of the host matrix at the surface plasmon resonance, any change 'in the dielectric constant of the material surrounding the metal nanoparticles results in a shift in the surface plasmon wavelength. During gelation the surface plasmon resonance shifts to the red as the average or effective dielectric constant of the matrix increases. Conversely, formation of an aerogel or xerogel through supercritical extraction or evaporation of the solvent produces a blue shift in the resonance indicating a decrease in the dielectric constant of the matrix. From the magnitude of this shift we deduce the average fraction of air and of silica in contact with the metal particles. The surface area of metal available for catalytic gas reaction may thus be determined.

  16. A new method of evaluating tight gas sands pore structure from nuclear magnetic resonance (NMR) logs

    NASA Astrophysics Data System (ADS)

    Xiao, Liang; Mao, Zhi-qiang; Xie, Xiu-hong

    2016-04-01

    Tight gas sands always display such characteristics of ultra-low porosity, permeability, high irreducible water, low resistivity contrast, complicated pore structure and strong heterogeneity, these make that the conventional methods are invalid. Many effective gas bearing formations are considered as dry zones or water saturated layers, and cannot be identified and exploited. To improve tight gas sands evaluation, the best method is quantitative characterizing rock pore structure. The mercury injection capillary pressure (MICP) curves are advantageous in predicting formation pore structure. However, the MICP experimental measurements are limited due to the environment and economy factors, this leads formation pore structure cannot be consecutively evaluated. Nuclear magnetic resonance (NMR) logs are considered to be promising in evaluating rock pore structure. Generally, to consecutively quantitatively evaluate tight gas sands pore structure, the best method is constructing pseudo Pc curves from NMR logs. In this paper, based on the analysis of lab experimental results for 20 core samples, which were drilled from tight gas sandstone reservoirs of Sichuan basin, and simultaneously applied for lab MICP and NMR measurements, the relationships of piecewise power function between nuclear magnetic resonance (NMR) transverse relaxation T2 time and pore-throat radius Rc are established. A novel method, which is used to transform NMR reverse cumulative curve as pseudo capillary pressure (Pc) curve is proposed, and the corresponding model is established based on formation classification. By using this model, formation pseudo Pc curves can be consecutively synthesized. The pore throat radius distribution, and pore structure evaluation parameters, such as the average pore throat radius (Rm), the threshold pressure (Pd), the maximum pore throat radius (Rmax) and so on, can also be precisely extracted. After this method is extended into field applications, several tight gas

  17. Markov Chain Monte Carlo Used in Parameter Inference of Magnetic Resonance Spectra

    DOE PAGES

    Hock, Kiel; Earle, Keith

    2016-02-06

    In this paper, we use Boltzmann statistics and the maximum likelihood distribution derived from Bayes’ Theorem to infer parameter values for a Pake Doublet Spectrum, a lineshape of historical significance and contemporary relevance for determining distances between interacting magnetic dipoles. A Metropolis Hastings Markov Chain Monte Carlo algorithm is implemented and designed to find the optimum parameter set and to estimate parameter uncertainties. In conclusion, the posterior distribution allows us to define a metric on parameter space that induces a geometry with negative curvature that affects the parameter uncertainty estimates, particularly for spectra with low signal to noise.

  18. Upstream processes in antibody production: evaluation of critical parameters.

    PubMed

    Jain, Era; Kumar, Ashok

    2008-01-01

    The demand for monoclonal antibody for therapeutic and diagnostic applications is rising constantly which puts up a need to bring down the cost of its production. In this context it becomes a prerequisite to improve the efficiency of the existing processes used for monoclonal antibody production. This review describes various upstream processes used for monoclonal antibody production and evaluates critical parameters and efforts which are being made to enhance the efficiency of the process. The upstream technology has tremendously been upgraded from host cells used for manufacturing to bioreactors type and capacity. The host cells used range from microbial, mammalian to plant cells with mammalian cells dominating the scenario. Disposable bioreactors are being promoted for small scale production due to easy adaptation to process validation and flexibility, though they are limited by the scale of production. In this respect Wave bioreactors for suspension culture have been introduced recently. A novel bioreactor for immobilized cells is described which permits an economical and easy alternative to hollow fiber bioreactor at lab scale production. Modification of the cellular machinery to alter their metabolic characteristics has further added to robustness of cells and perks up cell specific productivity. The process parameters including feeding strategies and environmental parameters are being improved and efforts to validate them to get reproducible results are becoming a trend. Online monitoring of the process and product characterization is increasingly gaining importance. In total the advancement of upstream processes have led to the increase in volumetric productivity by 100-fold over last decade and make the monoclonal antibody production more economical and realistic option for therapeutic applications.

  19. Variable-Rate Pumping Test Analysis for Aquifer Parameter Evaluation

    NASA Astrophysics Data System (ADS)

    Birdsell, K. H.; Mishra, P. K.

    2011-12-01

    The most common method to infer aquifer properties is based on analysis of drawdown and/or recovery data recorded from pumping tests. The analysis is frequently based on fitting observed pressure responses to appropriate analytical solutions for radial flow towards the pumping well. For mathematical simplicity, analytical solutions are commonly derived for constant-rate pumping conditions. However, often times the pumping rate during the test is varied either intentionally or due to technical difficulties during the test. Using principles of superposition, the constant-rate analytical solutions are frequently applied to analyze pumping tests that are conducted with variable pumping rates. In this study, we propose a novel methodology that approximates a time-varying pumping history as a series of segments with linearly varying pumping rates, and use it to evaluate the effects of pumping variation on aquifer parameter estimation. Our approach is demonstrated using existing analytical solutions for confined aquifers (Mishra and Neuman 2011), but it is also applicable to unconfined and/or leaky aquifers. The methodology is validated using a synthetic pumping test. We also apply our methodology to analyze the pumping test data by inversely estimating the apparent aquifer parameters using the code MADS (http://ees.lanl.gov/staff/monty/codes/mads).

  20. Evaluating parasite densities and estimation of parameters in transmission systems.

    PubMed

    Heinzmann, D; Torgerson, P R

    2008-09-01

    Mathematical modelling of parasite transmission systems can provide useful information about host parasite interactions and biology and parasite population dynamics. In addition good predictive models may assist in designing control programmes to reduce the burden of human and animal disease. Model building is only the first part of the process. These models then need to be confronted with data to obtain parameter estimates and the accuracy of these estimates has to be evaluated. Estimation of parasite densities is central to this. Parasite density estimates can include the proportion of hosts infected with parasites (prevalence) or estimates of the parasite biomass within the host population (abundance or intensity estimates). Parasite density estimation is often complicated by highly aggregated distributions of parasites within the hosts. This causes additional challenges when calculating transmission parameters. Using Echinococcus spp. as a model organism, this manuscript gives a brief overview of the types of descriptors of parasite densities, how to estimate them and on the use of these estimates in a transmission model.

  1. Evaluation of Neonatal Hemolytic Jaundice: Clinical and Laboratory Parameters

    PubMed Central

    Cherepnalkovski, Anet Papazovska; Krzelj, Vjekoslav; Zafirovska-Ivanovska, Beti; Gruev, Todor; Markic, Josko; Aluloska, Natasa; Zdraveska, Nikolina; Piperkovska, Katica

    2015-01-01

    BACKGROUND: Neonatal jaundice that occurs in ABO or Rhesus issoimunisation has been recognized as one of the major risk factors for development of severe hyperbilirubinemia and bilirubin neurotoxicity. AIM: Aim of our study was to investigate clinical and laboratory parameters associated with hemolytic jaundice due to Rh and ABO incompatibility and compare results with the group of unspecific jaundice. MATERIAL AND METHODS: One hundred sixty seven (167) neonatal hyperbilirubinemia cases were included in the study, 24.6% of which presented with ABO/Rhesus type hemolytic jaundice, and the rest with unspecific jaundice. Evaluation included: blood count, reticulocites, serum bilirubin, aminotransferases, blood grouping, and Coombs test, also the day of bilirubin peak, duration of the hyperbilirubinemia, and additional bilirubin measurements. RESULTS: We showed significantly lower mean values of hemoglobin, erythrocytes and hematocrit and significantly higher values of reticulocytes in the group of ABO/Rh incompatibility compared to the group of jaundice of unspecific etiology; also an earlier presentation and a higher-grade jaundice in this group. CONCLUSIONS: The laboratory profile in ABO/Rh isoimmunisation cases depicts hemolytic mechanism of jaundice. These cases carry a significant risk for early and severe hyperbilirubinemia and are eligible for neurodevelopmental follow-up. Hematological parameters and blood grouping are simple diagnostic methods that assist the etiological diagnosis of neonatal hyperbilirubinemia. PMID:27275310

  2. Recent Cross-Section Evaluations in the Resonance Region at the Oak Ridge National Laboratory

    SciTech Connect

    Leal, L.C.; Derrien, H.; Guber, K.H.; Sayer, R.; Larson, N.M.

    2005-05-24

    The intent of this work is to present the results and to describe the procedures utilized to evaluate 233U and 19F for criticality safety applications. The evaluation was done in the resolved resonance region using the reduced Reich-Moore R-matrix formalism. The resonance analysis was performed with the multilevel R-matrix code SAMMY, which utilizes the generalized least-squares technique based on Bayes theory.

  3. Generalized Parameter-Adjusted Stochastic Resonance of Duffing Oscillator and Its Application to Weak-Signal Detection.

    PubMed

    Lai, Zhi-Hui; Leng, Yong-Gang

    2015-08-28

    A two-dimensional Duffing oscillator which can produce stochastic resonance (SR) is studied in this paper. We introduce its SR mechanism and present a generalized parameter-adjusted SR (GPASR) model of this oscillator for the necessity of parameter adjustments. The Kramers rate is chosen as the theoretical basis to establish a judgmental function for judging the occurrence of SR in this model; and to analyze and summarize the parameter-adjusted rules under unmatched signal amplitude, frequency, and/or noise-intensity. Furthermore, we propose the weak-signal detection approach based on this GPASR model. Finally, we employ two practical examples to demonstrate the feasibility of the proposed approach in practical engineering application.

  4. Generalized Parameter-Adjusted Stochastic Resonance of Duffing Oscillator and Its Application to Weak-Signal Detection

    PubMed Central

    Lai, Zhi-Hui; Leng, Yong-Gang

    2015-01-01

    A two-dimensional Duffing oscillator which can produce stochastic resonance (SR) is studied in this paper. We introduce its SR mechanism and present a generalized parameter-adjusted SR (GPASR) model of this oscillator for the necessity of parameter adjustments. The Kramers rate is chosen as the theoretical basis to establish a judgmental function for judging the occurrence of SR in this model; and to analyze and summarize the parameter-adjusted rules under unmatched signal amplitude, frequency, and/or noise-intensity. Furthermore, we propose the weak-signal detection approach based on this GPASR model. Finally, we employ two practical examples to demonstrate the feasibility of the proposed approach in practical engineering application. PMID:26343671

  5. Design parameters of a resonant infrared photoconductor with unity quantum efficiency

    NASA Technical Reports Server (NTRS)

    Farhoomand, Jam; Mcmurray, Robert E., Jr.

    1991-01-01

    This paper proposes a concept of a resonant infrared photoconductor that has characteristics of 100 percent quantum efficiency, high photoconductive gain, and very low noise equivalent power. Central to this concept is an establishment of a high-finesse absorption cavity internal to the detector element. A theoretical analysis is carried out, demonstrating this concept and providing some design guidelines. A Ge:Ga FIR detector is presently being fabricated using this approach.

  6. Approximate Schumann resonance parameters for a two-scale-height ionosphere

    NASA Technical Reports Server (NTRS)

    Sentman, D. D.

    1990-01-01

    An isotropic, spherically symmetric two-scale-height ionosphere's transverse magnetic mode eigenfrequencies, as well as the height and angular profiles of its electric and magnetic fields, are presently addressed by an approximate solution. The electromagnetic energy in the eigenmodes is equally partitioned between the electric and magnetic fields, allowing a simple expression of the relative degrees of dissipation within the radial and tangential dissipation layers. The results obtained may be relevant to interpretations of the temporal variations in the Schumann resonances.

  7. Molecular dynamics simulations: Parameter evaluation, application and development

    NASA Astrophysics Data System (ADS)

    Zhou, Jin

    Molecular dynamics (MD) simulation is a theoretical technique for investigating the physical properties of a wide variety of molecules. This dissertation contains my studies on three important parts of the MD simulation: evaluation of parameters in empirical energy functions widely used in MD simulations, application of MD simulation on experimentally interested biological molecules and development of new methods for constraint dynamics simulations. All the work in this thesis made use of CHARMM as an MD simulation tool. The MD simulation uses empirical energy functions parameterized by a set of parameters. These parameters play an important role in the quality of the simulations. I evaluated nine parameter sets from Harvard University and Molecular Simulations, Inc. for protein simulations by the MD simulations of hydrated form of carboxy- myoglobin and interleukin-1/beta, which are rich in two typical protein structure motifs, helix and β sheet structures respectively. It is found that some sets are good at representing helical structure proteins while others are good at β sheet proteins. But all of them need improvement on representing motions at low temperature. Experimental evidence indicates that the 1A coiled-coil domains of the Intermediate Filament (IF) proteins consisting of coiled human keratins 1 and 10 (K1 and K10) are 'hot spots' for substitutional mutations. Some of these mutations are correlated to the human skin diseases-epidermolytic hyperkeratiosis (EH) and epidermolysis bullosa simplex (EBS). The MD simulation technique is used here for the first time to model and simulate these proteins to elucidate the molecular-level effects of these mutations. Lacking the experimental crystal structures, the initial structure of 1A domain of the wild type Intermediate Filament protein and its mutants were modeled from scratch to reproduce the well- known properties of the proteins of this kind followed by identical MD simulations. The important result is

  8. Referencing strategy for the direct comparison of nuclear magnetic resonance and molecular dynamics motional parameters in RNA.

    PubMed

    Musselman, Catherine; Zhang, Qi; Al-Hashimi, Hashim; Andricioaei, Ioan

    2010-01-21

    Nuclear magnetic resonance (NMR) spectroscopy and molecular dynamics (MD) simulations are both techniques that can be used to characterize the structural dynamics of biomolecules and their underlying time scales. Comparison of relaxation parameters obtained through each methodology allows for cross validation of techniques and for complementarity in the analysis of dynamics. Here we present a combined NMR/MD study of the dynamics of HIV-1 transactivation response (TAR) RNA. We compute relaxation constants (R(1), R(2), and NOE) and model-free parameters (S(2) and tau) from a 65 ns molecular dynamics (MD) trajectory and compare them with the respective parameters measured in a domain-elongation NMR experiment. Using the elongated domain as the frame of reference for all computed parameters allows for a direct comparison between experiment and simulation. We see good agreement for many parameters and gain further insight into the nature of the local and global dynamics of TAR, which are found to be quite complex, spanning multiple time scales. For the few cases where agreement is poor, comparison of the dynamical parameters provides insight into the limits of each technique. We suggest a frequency-matching procedure that yields an upper bound for the time scale of dynamics to which the NMR relaxation experiment is sensitive.

  9. Dependence of nuclear quadrupole resonance transitions on the electric field gradient asymmetry parameter for nuclides with half-integer spins

    SciTech Connect

    Cho, Herman

    2016-09-01

    Allowed transition energies and eigenstate expansions have been calculated and tabulated in numerical form as functions of the electric field gradient asymmetry parameter for the zero field Hamiltonian of quadrupolar nuclides with I = 3/2, 5/2, 7/2, and 9/2. These results may be used to interpret nuclear quadrupole resonance (NQR) spectra and extract accurate values of the electric field gradient tensors. Applications of NQR methods to studies of electronic structure in heavy element systems are proposed. This material is based upon work supported by the U.S. Department of Energy Office of Science, Office of Basic Energy Sciences, Heavy Element Chemistry program.

  10. Cardiac Magnetic Resonance for Evaluating Catheter Related FDG Avidity

    PubMed Central

    Gage, Kenneth L.; Berman, Claudia G.; Montilla-Soler, Jaime L.

    2016-01-01

    A 53-year-old female with a history of metastatic left arm melanoma presented for F(18) fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) which showed a moderately FDG avid focus at her port catheter tip near the cavoatrial junction. Although catheter tip related FDG avidity has previously been suggested to be bland thrombus or infection, melanoma can metastasize to unusual locations including the superior vena cava. In addition, the patient had an elevated risk of anticoagulation due to a history of hemorrhagic brain metastases. Therefore, confirmatory cardiac magnetic resonance (CMR) was obtained and findings were consistent with bland catheter-related thrombus. PMID:27867676

  11. Approaches to real-time tsunami wave parameters evaluation

    NASA Astrophysics Data System (ADS)

    Lavrentyev, Mikhail; Titov, Vasily; Romanenko, Alexey

    2014-05-01

    Timely prediction of tsunami wave parameters is still among actual problems for tsunami risk mitigation. After the Great East Japan Earthquake (Mach 11, 2011) it takes only 20 minutes for tsunami wave to approach the cost of Japan after the quake. Existing models and software applications allow experts to simulate tsunami wave propagation rather fast. However, all the models require knowledge about initial see-face disturbance at tsunami source. Seismic data, available right after the event, provide the information about earthquake magnitude and epicenter location. There are a number of approaches to evaluate the initial see-face disturbance (using knowledge about the trench geo structure, satellite imaging, etc.). One of perspective approaches is to recalculate tsunami wave profiles, recorded by deep-ocean stations like DART buoys or GPS equipment, in terms of initial sea surface displacement. The so-called preliminary calculation strategy suggests that the targeted subduction zone is covered by a number rectangular "unit sources" 50x100 km. Wave propagation from each unit source, caused by the unified shape (typical for the given subduction zone), is calculated in advance other the entire aquatoria. After real event the wave profile, measure at certain sensor, is approximated as linear combination of model signals from the above unit sources, calculated at the same point. Method was proved to be rather accurate. However, it takes valuable time to recover initial displacement at tsunami source in case of larger zone of disturbance (e.g. about 20 minutes for processing tsunami epicenter covered with six unit-sources). We suggest new algorithm for above mentioned model. This is based on Fourier theory and involves orthogonal decomposition of simulated profiles, calculated from the unit sources. It takes only about 1 second to recover tsunami source of twenty unit-sources. This allows one to speak about possibility to develop real-time system for evaluating tsunami.

  12. An Analysis Method for Superconducting Resonator Parameter Extraction with Complex Baseline Removal

    NASA Technical Reports Server (NTRS)

    Cataldo, Giuseppe

    2014-01-01

    A new semi-empirical model is proposed for extracting the quality (Q) factors of arrays of superconducting microwave kinetic inductance detectors (MKIDs). The determination of the total internal and coupling Q factors enables the computation of the loss in the superconducting transmission lines. The method used allows the simultaneous analysis of multiple interacting discrete resonators with the presence of a complex spectral baseline arising from reflections in the system. The baseline removal allows an unbiased estimate of the device response as measured in a cryogenic instrumentation setting.

  13. Evaluation of Elution Parameters for Cesium Ion Exchange Resins

    SciTech Connect

    Burgeson, Ingrid E.; Deschane, Jaquetta R.; Cook, Bryan J.; Blanchard, David L.; Weier, Dennis R.

    2006-08-28

    Cesium ion exchange is one of the planned processes for treating and disposing of waste at the U.S. Department of Energy Hanford Site. Radioactive supernatant liquids from the waste tanks will undergo ultrafiltration, followed by cesium ion exchange using a regenerable organic ion exchange resin. Two resins, SuperLig?644 and a Resorcinol-formaldehyde resin are being evaluated for cesium removal and cesium elution characteristics. The main purpose of this study is to optimize the cesium elution to provide a resin which after undergoing elution would meet the U.S. Department of Energy/Office of River Protection Project-Waste Treatment Plant processing and resin disposal criteria. Columns of each resin type were loaded to greater or equal to 90% breakthrough with a Hanford waste stimulant and eluted with nitric acid. The temperature, flow rate and nitric acid concentration were varied to determine the optimal elution conditions. Temperature and eluant flow rate were the most important elution parameters. As would be predicted based upon kinetic consideration alone, decreasing the eluant flow rate and increasing the temperature provided the optimal elution conditions. Varying the nitric acid concentration did not have a significant effect on the elution; however, elutions performed using both high acid concentration (1M) and elevated temperature (45 C) resulted in resin degradation, causing gas generation and resin bed disruption.

  14. Rapid Scan Electron Paramagnetic Resonance Opens New Avenues for Imaging Physiologically Important Parameters In Vivo.

    PubMed

    Biller, Joshua R; Mitchell, Deborah G; Tseytlin, Mark; Elajaili, Hanan; Rinard, George A; Quine, Richard W; Eaton, Sandra S; Eaton, Gareth R

    2016-09-26

    We demonstrate a superior method of 2D spectral-spatial imaging of stable radical reporter molecules at 250 MHz using rapid-scan electron-paramagnetic-resonance (RS-EPR), which can provide quantitative information under in vivo conditions on oxygen concentration, pH, redox status and concentration of signaling molecules (i.e., OH(•), NO(•)). The RS-EPR technique has a higher sensitivity, improved spatial resolution (1 mm), and shorter acquisition time in comparison to the standard continuous wave (CW) technique. A variety of phantom configurations have been tested, with spatial resolution varying from 1 to 6 mm, and spectral width of the reporter molecules ranging from 16 µT (160 mG) to 5 mT (50 G). A cross-loop bimodal resonator decouples excitation and detection, reducing the noise, while the rapid scan effect allows more power to be input to the spin system before saturation, increasing the EPR signal. This leads to a substantially higher signal-to-noise ratio than in conventional CW EPR experiments.

  15. Assessment of Gate Width Size on Lifetime-Based Förster Resonance Energy Transfer Parameter Estimation

    PubMed Central

    Chen, Sez-Jade; Sinsuebphon, Nattawut; Intes, Xavier

    2015-01-01

    Förster Resonance Energy Transfer (FRET) enables the observation of interactions at the nanoscale level through the use of fluorescence optical imaging techniques. In FRET, fluorescence lifetime imaging can be used to quantify the fluorescence lifetime changes of the donor molecule, which are associated with proximity between acceptor and donor molecules. Among the FRET parameters derived from fluorescence lifetime imaging, the percentage of donor that interacts with the acceptor (in proximity) can be estimated via model-based fitting. However, estimation of the lifetime parameters can be affected by the acquisition parameters such as the temporal characteristics of the imaging system. Herein, we investigate the effect of various gate widths on the accuracy of estimation of FRET parameters with focus on the near-infrared spectral window. Experiments were performed in silico, in vitro, and in vivo with gate width sizes ranging from 300 ps to 1000 ps in intervals of 100 ps. For all cases, the FRET parameters were retrieved accurately and the imaging acquisition time was decreased three-fold. These results indicate that increasing the gate width up to 1000 ps still allows for accurate quantification of FRET interactions even in the case of short lifetimes such as those encountered with near-infrared FRET pairs. PMID:26557647

  16. Fully self-consistent study of charge-exchange resonances and the impact on the symmetry energy parameters

    NASA Astrophysics Data System (ADS)

    Roca-Maza, X.; Cao, Li-Gang; Colò, G.; Sagawa, H.

    2016-10-01

    We have examined within a fully self-consistent theoretical framework the energy difference between the anti-analog giant dipole resonance (AGDR) and the isobaric analog state (IAS), EAGDR-EIAS , as an indicator of the neutron skin and of the density behavior of the symmetry energy. We have improved two specific points in our HF+RPA calculations: (1) the exchange term of the two-body Coulomb interaction is treated exactly without Slater approximation; and (2) the two-parameters spin-orbit interaction is treated in a consistent way within the energy density functional theory. The estimated values for the neutron skin in 208Pb and the slope parameter of symmetry energy are compared with previous analysis available in the literature.

  17. Harvesting rockfall hazard evaluation parameters from Google Earth Street View

    NASA Astrophysics Data System (ADS)

    Partsinevelos, Panagiotis; Agioutantis, Zacharias; Tripolitsiotis, Achilles; Steiakakis, Chrysanthos; Mertikas, Stelios

    2015-04-01

    Rockfall incidents along highways and railways prove extremely dangerous for properties, infrastructures and human lives. Several qualitative metrics such as the Rockfall Hazard Rating System (RHRS) and the Colorado Rockfall Hazard Rating System (CRHRS) have been established to estimate rockfall potential and provide risk maps in order to control and monitor rockfall incidents. The implementation of such metrics for efficient and reliable risk modeling require accurate knowledge of multi-parametric attributes such as the geological, geotechnical, topographic parameters of the study area. The Missouri Rockfall Hazard Rating System (MORH RS) identifies the most potentially problematic areas using digital video logging for the determination of parameters like slope height and angle, face irregularities, etc. This study aims to harvest in a semi-automated approach geometric and qualitative measures through open source platforms that may provide 3-dimensional views of the areas of interest. More specifically, the Street View platform from Google Maps, is hereby used to provide essential information that can be used towards 3-dimensional reconstruction of slopes along highways. The potential of image capturing along a programmable virtual route to provide the input data for photogrammetric processing is also evaluated. Moreover, qualitative characterization of the geological and geotechnical status, based on the Street View images, is performed. These attributes are then integrated to deliver a GIS-based rockfall hazard map. The 3-dimensional models are compared to actual photogrammetric measures in a rockfall prone area in Crete, Greece while in-situ geotechnical characterization is also used to compare and validate the hazard risk. This work is considered as the first step towards the exploitation of open source platforms to improve road safety and the development of an operational system where authorized agencies (i.e., civil protection) will be able to acquire near

  18. Magnetic resonance evaluation of hydronephrosis in the dog

    SciTech Connect

    Thickman, D.; Kundel, H.; Biery, D.

    1984-07-01

    The ability of magnetic resonance (MR) imaging to detect and distinguish various stages of obstruction in the canine kidney was investigated. MR images were obtained at acute, subacute, and chronic stages of experimentally produced hydronephrosis. The renal cortex was distinguished from the renal medulla in the normal dog and in the acute and subacute stages of hydronephrosis. T1 relaxation times of the renal cortex and medulla were measured in vitro in 14 normal and nine experimental animals. These values were used to compute the amount of tissue contrast between the cortex and medulla and were compared with the degree of corticomedullary differentiation seen in the image. A relationship was noted between increasing T1 values and increasing water content. Corticomedullary contrast decreased with obstruction. The variation in corticomedullary image contracts may be useful for assessing the duration of hydronephrosis.

  19. Reevaluation of 58Ni and 60Ni Resonance Parameters in the Energy Range Thermal to 800 keV

    SciTech Connect

    Derrien, Herve; Leal, Luiz C; Guber, Klaus H; Wiarda, Dorothea; Arbanas, Goran

    2009-01-01

    The previous 58Ni and 60Ni set of resonance parameters (ENDF/B-VII-0, JEFF-3, etc.) was based on the SAMMY analysis of Oak Ridge National Laboratory neutron transmission, scattering cross section and capture cross section measurements by C. M. Perey et al. The present results were obtained by adding to the SAMMY experimental data base the capture cross sections measured recently at the Oak Ridge Linear Electron Accelerator by Guber et al. and the Geel Electron Linear Accelerator very high-resolution neutron transmission measurements performed by Brusegan et al. A complete resonance parameter covariance matrix (RPCM) was obtained from the SAMMY analysis of the experimental database. The data sets were made consistent, when needed, by adjusting the neutron energy scales, the normalization coefficients, and the background corrections. The RPCM allows the calculation of the cross section uncertainties due mainly to statistical errors in the experimental data. The systematic uncertainties of the experimental data, estimated from the preliminary analyses of the experimental database, were taken into account in the cross section covariance matrix (CSCM) for total, scattering, and capture cross sections. The diagonal elements of the CSCM were obtained by quadratic combination of the different components of the uncertainties. Because of a lack of experimental information, the energy correlations were not obtained, and a value of 0.5 was arbitrarily taken for all the CSCM nondiagonal elements.

  20. Evaluation of a microwave resonator for predicting grain moisture independent of bulk density

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This work evaluated the ability of a planar whispering mode resonator to predict moisture considering moisture and densities expected in an on-harvester application. A calibration model was developed to accurately predict moisture over the moisture, density and temperature ranges evaluated. This mod...

  1. Anomalous Solute Transport in Saturated Porous Media: Linking Transport Model Parameters to Electrical and Nuclear Magnetic Resonance Properties

    NASA Astrophysics Data System (ADS)

    Swanson, R. D.; Binley, A. M.; Keating, K.; France, S.; Osterman, G. K.; Day-Lewis, F. D.; Singha, K.

    2013-12-01

    The advection-dispersion equation fails to describe non-Fickian solute transport in saturated porous media, necessitating the use of other models. The dual-domain mass transfer (DDMT) model partitions the total porosity into mobile and less-mobile domains with solute exchange between the domains; consequently, the DDMT model can produce a better fit to breakthrough curves (BTCs) in systems defined by more- and less-mobile components. However, direct experimental estimation of DDMT model parameters such as rate of exchange and the mobile and less-mobile porosities remains elusive. Consequently, model parameters are often calculated purely as a model fitting exercise. There is a clear need for material characterization techniques that can offer some insight into the pore space geometrical arrangement, particularly if such techniques can be extended to the field scale. Here, we interpret static direct-current (DC) resistivity, complex resistivity (CR) and nuclear magnetic resonance (NMR) geophysical measurements in the characterization of mass transfer parameters. We use two different samples of the zeolite clinoptilolite, a material shown to demonstrate solute mass transfer due to a significant intragranular porosity, along with glass beads as a control. We explore the relation between geophysical and DDMT parameters in conjunction with supporting material characterization methods. Our results reveal how these geophysical measurements can offer some insight into the pore structures controlling the observed anomalous transport behavior.

  2. Decimative Subspace-Based Parameter Estimation Techniques Applied to Magnetic Resonance Spectroscopy Signals

    DTIC Science & Technology

    2007-11-02

    DESE : another decimative subspace-based parameter estimation algorithm, recently proposed as Decimative Spectral Estimation [3]. In what follows...Sponsoring/Monitoring Agency Name(s) and Address(es) US Army Research , Development & Standardization Group (UK) PSC 802 Box 15 FPO AE 09499-1500 Sponsor...1DXstackX∗stack. (12) C. DESE This algorithm was presented very recently [3]. Like HTLS, DESE also makes use of the SVD of a Hankel ma- trix and the

  3. Determination of GLUT1 Oligomerization Parameters using Bioluminescent Förster Resonance Energy Transfer

    PubMed Central

    Looyenga, Brendan; VanOpstall, Calvin; Lee, Zion; Bell, Jed; Lodge, Evans; Wrobel, Katherine; Arnoys, Eric; Louters, Larry

    2016-01-01

    The facilitated glucose transporter GLUT1 (SLC2A1) is an important mediator of glucose homeostasis in humans. Though it is found in most cell types to some extent, the level of GLUT1 expression across different cell types can vary dramatically. Prior studies in erythrocytes—which express particularly high levels of GLUT1—have suggested that GLUT1 is able to form tetrameric complexes with enhanced transport activity. Whether dynamic aggregation of GLUT1 also occurs in cell types with more modest expression of GLUT1, however, is unclear. To address this question, we developed a genetically encoded bioluminescent Förster resonance energy transfer (BRET) assay using the luminescent donor Nanoluciferase and fluorescent acceptor mCherry. By tethering these proteins to the N-terminus of GLUT1 and performing saturation BRET analysis, we were able to demonstrate the formation of multimeric complexes in live cells. Parallel use of flow cytometry and immunoblotting further enabled us to estimate the density of GLUT1 proteins required for spontaneous oligomerization. These data provide new insights into the physiological relevance of GLUT1 multimerization as well as a new variant of BRET assay that is useful for measuring the interactions among other cell membrane proteins in live cells. PMID:27357903

  4. Active Plasma Resonance Spectroscopy: Evaluation of a fluiddynamic-model of the planar multipole resonance probe using functional analytic methods

    NASA Astrophysics Data System (ADS)

    Friedrichs, Michael; Brinkmann, Ralf Peter; Oberrath, Jens

    2016-09-01

    Measuring plasma parameters, e.g. electron density and electron temperature, is an important procedure to verify the stability and behavior of a plasma process. For this purpose the multipole resonance probe (MRP) represents a satisfying solution to measure the electron density. However the influence of the probe on the plasma through its physical presence makes it unattractive for some processes in industrial application. A solution to combine the benefits of the spherical MRP with the ability to integrate the probe into the plasma reactor is introduced by the planar model of the MRP. By coupling the model of the cold plasma with the maxwell equations for electrostatics an analytical model for the admittance of the plasma is derivated, adjusted to cylindrical geometry and solved analytically for the planar MRP using functional analytic methods.

  5. Preliminary resolved resonance region evaluation of copper-63 from 0 to 300 keV

    SciTech Connect

    Sobes, V.; Forget, B.; Leal, L.; Guber, K.

    2012-07-01

    A new preliminary evaluation of Cu-63 was done in the energy region from 0 to 300 keV extending the resolved resonance region of the previous, ENDF/B-VII.0, evaluation three-fold. The new evaluation was based on three experimental transmission data sets; two measured at the Oak Ridge Electron Linear Accelerator (ORELA) and one from the Massachusetts Inst. of Technology Nuclear Reactor (MITR). A total of 275 new resonances were identified and a corresponding set of external resonances was approximated to mock up the external levels. The negative external levels (bound level) were modified to match the thermal cross section values. A preliminary benchmarking calculation was made using 11 ICSBEP benchmarks. This work is in support of the DOE Nuclear Criticality Safety Program. (authors)

  6. Evaluation of the storage function model parameter characteristics

    NASA Astrophysics Data System (ADS)

    Sugiyama, Hironobu; Kadoya, Mutsumi; Nagai, Akihiro; Lansey, Kevin

    1997-04-01

    The storage function hydrograph model is one of the most commonly used models for flood runoff analysis in Japan. This paper studies the generality of the approach and its application to Japanese basins. Through a comparison of the basic equations for the models, the storage function model parameters, K, P, and T1, are shown to be related to the terms, k and p, in the kinematic wave model. This analysis showed that P and p are identical and K and T1 can be related to k, the basin area and its land use. To apply the storage function model throughout Japan, regional parameter relationships for K and T1 were developed for different land-use conditions using data from 22 watersheds and 91 flood events. These relationships combine the kinematic wave parameters with general topographic information using Hack's Law. The sensitivity of the parameters and their physical significance are also described.

  7. Evaluation of Personnel Parameters in Software Cost Estimating Models

    DTIC Science & Technology

    2007-11-02

    ACAP , 1.42; all other parameters would be set to the nominal value of one. The effort multiplier will be a fixed value if the model uses linear...data. The calculated multiplier values were the 45 Table 8. COSTAR Trials For Multiplier Calculation Run ACAP PCAP PCON APEX PLEX LTEX Effort...impact. Table 9. COCOMO II Personnel Parameters Effort Multipliers Driver Lowest Nominal Highest Analyst Capability ( ACAP ) 1.42 1.00 0.71

  8. Interrogating the origin and behavior of magnetic resonance diffusion tensor scalar parameters in the myocardium

    NASA Astrophysics Data System (ADS)

    Abdullah, Osama Mahmoud

    Myocardial microstructure plays an important role in sustaining the orchestrated beating motion of the heart. Several microstructural components, including myocytes and auxiliary cells, extracellular space, and blood vessels provide the infrastructure for normal heart function, including excitation propagation, myocyte contraction, delivery of oxygen and nutrients, and removing byproduct wastes. Cardiac diseases cause deleterious changes to some or all of these microstructural components in the detrimental process of cardiac remodeling. Since heart failure is among the leading causes of death in the world, new and novel tools to noninvasively characterize heart microstructure are needed for monitoring and staging of cardiac disease. In this regards, diffusion magnetic resonance imaging (MRI) provides a promising framework to probe and quantify tissue microstructure without the need for exogenous contrast agent. As diffusion in 3-dimensional space is characterized by the diffusion tensor, MR diffusion tensor imaging (DTI) is being used to noninvasively measure anisotropic diffusion, and thus the magnitude and spatial orientation of microstructural organization of tissues, including the heart. However, even though in vivo cardiac DTI has become more clinically available, to date the origin and behavior of different microstructural components on the measured DTI signal remain to be explicitly specified. The presented studies in this work demonstrate that DTI can be used as a noninvasive and contrast-free imaging modality to characterize myocyte size and density, extracellular collagen content, and the directional magnitude of blood flow. The identified applications are expected to provide metrics to enable physicians to detect, quantify, and stage different microstructural components during progression of cardiac disease.

  9. Evaluation of the Performance Characteristics of BVA Resonators under Static and Dynamic Conditions.

    DTIC Science & Technology

    1981-08-01

    AO-AI05 064 FREQUENCY AND TIME SYSTEMS INC BEVERLY MA F/S 9/1. EVALUATION OF THE PERFORMANCE CHARACTERISTICS OF BVA RESONATORS--ETC(UI AUG 81 D A...HARACTERISTICS OF BVA ESONATORS UNDER STATIC AND YNAMIC CONDITIONS ecuency and Time Systems, Inc. DTIC ELECTE DonaW A. Emmons C APIROVED FOR PUlIC RELEASE... Time Systems, Inc. (FTS) relatinq to a novel quartz frequency control element, the BVA resonator. The pur- pose of the study has been to evaluate the

  10. Evaluation of magnetic resonance safety of veterinary radiofrequency identification devices at 1 T.

    PubMed

    Baker, Martin A; MacDonald, Iain

    2011-01-01

    Implants containing metallic components have the potential to become heated or move within the patient while in the magnetic resonance (MR) environment. Despite containing a ferromagnetic core and having been in use for over 20 years, no information is available on the safety of veterinary radiofrequency identification devices during MR examinations. These devices are the most commonly encountered metallic implants in dogs and cats undergoing MR imaging. Three commercial veterinary microchips were evaluated for safety in the MR environment at 1 T. Parameters tested were translational force, torque, heating, artifact production, and function. Translation and torque were larger than that expected from normal activity under normal gravity. No significant heating was observed. Signal void artifacts may affect diagnosis if they are too close to the area of clinical importance. Microchip function was unaffected by routine clinical MR imaging. Capsule formation around devices is a major factor in counteracting translation and torque. Our findings support that is acceptable for patients to undergo MR imaging with this 1 T system following an interval of 3 months postimplantation to allow capsule growth. Because of the complex interactions involved, these observations may not be translatable to MR scanners of different field strength and/or manufacturer. Further safety testing of these and other radiofrequency identification devices is therefore recommended at different field strengths and equipment specifications.

  11. Electron-paramagnetic-resonance parameters of molybdenum(V) in sulphite oxidase from chicken liver.

    PubMed Central

    Lamy, M T; Gutteridge, S; Bary, R C

    1980-01-01

    A study has been made of e.p.r. signals due to Mo(V) in reduced sulphite oxidase (EC 1.8.3.1) from chicken liver. Reduction by SO3(2-), or photochemically in the presence of a deazaflavin derivative, produces spectra indistinguishable from one another. Three types of spectra from the enzyme were distingusihed and shown to correspond to single chemical species, since they could be simulated at both 9 and 35 GHz by using the same parameters. These were the low-pH form of the enzyme, with gav. 1.9805, the high-pH form, with gav. 1.9681 and a phosphate complex, with gav. 1.9741. The low-H form shows interaction with a single exchangeable proton, with A(1H)av. (hyperfine coupling constant) = 0.98 mT, probably in the form of an MoOH group. Parameters of the signals are compared with those for signals from xanthine oxidase and nitrate reductase. The signal from the phosphate complex of sulphite oxidase in unique among anion complexes of Mo-containing enzymes in showing no hyperfine coupling to protons. There is no evidence for additional weakly coupled protons or nitrogen nuclei in the sulphite oxidase signals. The possibility is considered that the enzymic mechanism involves abstraction of a proton and two electrons from HSO3- by a Mo = O group in the enzyme. PMID:6249254

  12. Two statistics for evaluating parameter identifiability and error reduction

    USGS Publications Warehouse

    Doherty, John; Hunt, Randall J.

    2009-01-01

    Two statistics are presented that can be used to rank input parameters utilized by a model in terms of their relative identifiability based on a given or possible future calibration dataset. Identifiability is defined here as the capability of model calibration to constrain parameters used by a model. Both statistics require that the sensitivity of each model parameter be calculated for each model output for which there are actual or presumed field measurements. Singular value decomposition (SVD) of the weighted sensitivity matrix is then undertaken to quantify the relation between the parameters and observations that, in turn, allows selection of calibration solution and null spaces spanned by unit orthogonal vectors. The first statistic presented, "parameter identifiability", is quantitatively defined as the direction cosine between a parameter and its projection onto the calibration solution space. This varies between zero and one, with zero indicating complete non-identifiability and one indicating complete identifiability. The second statistic, "relative error reduction", indicates the extent to which the calibration process reduces error in estimation of a parameter from its pre-calibration level where its value must be assigned purely on the basis of prior expert knowledge. This is more sophisticated than identifiability, in that it takes greater account of the noise associated with the calibration dataset. Like identifiability, it has a maximum value of one (which can only be achieved if there is no measurement noise). Conceptually it can fall to zero; and even below zero if a calibration problem is poorly posed. An example, based on a coupled groundwater/surface-water model, is included that demonstrates the utility of the statistics. ?? 2009 Elsevier B.V.

  13. Anomalous solute transport in saturated porous media: Relating transport model parameters to electrical and nuclear magnetic resonance properties

    NASA Astrophysics Data System (ADS)

    Swanson, Ryan D.; Binley, Andrew; Keating, Kristina; France, Samantha; Osterman, Gordon; Day-Lewis, Frederick D.; Singha, Kamini

    2015-02-01

    The advection-dispersion equation (ADE) fails to describe commonly observed non-Fickian solute transport in saturated porous media, necessitating the use of other models such as the dual-domain mass-transfer (DDMT) model. DDMT model parameters are commonly calibrated via curve fitting, providing little insight into the relation between effective parameters and physical properties of the medium. There is a clear need for material characterization techniques that can provide insight into the geometry and connectedness of pore spaces related to transport model parameters. Here, we consider proton nuclear magnetic resonance (NMR), direct-current (DC) resistivity, and complex conductivity (CC) measurements for this purpose, and assess these methods using glass beads as a control and two different samples of the zeolite clinoptilolite, a material that demonstrates non-Fickian transport due to intragranular porosity. We estimate DDMT parameters via calibration of a transport model to column-scale solute tracer tests, and compare NMR, DC resistivity, CC results, which reveal that grain size alone does not control transport properties and measured geophysical parameters; rather, volume and arrangement of the pore space play important roles. NMR cannot provide estimates of more-mobile and less-mobile pore volumes in the absence of tracer tests because these estimates depend critically on the selection of a material-dependent and flow-dependent cutoff time. Increased electrical connectedness from DC resistivity measurements are associated with greater mobile pore space determined from transport model calibration. CC was hypothesized to be related to length scales of mass transfer, but the CC response is unrelated to DDMT.

  14. Evaluation of Multi-parameter Test Statistics for Multiple Imputation.

    PubMed

    Liu, Yu; Enders, Craig K

    2017-03-22

    In Ordinary Least Square regression, researchers often are interested in knowing whether a set of parameters is different from zero. With complete data, this could be achieved using the gain in prediction test, hierarchical multiple regression, or an omnibus F test. However, in substantive research scenarios, missing data often exist. In the context of multiple imputation, one of the current state-of-art missing data strategies, there are several different analogous multi-parameter tests of the joint significance of a set of parameters, and these multi-parameter test statistics can be referenced to various distributions to make statistical inferences. However, little is known about the performance of these tests, and virtually no research study has compared the Type 1 error rates and statistical power of these tests in scenarios that are typical of behavioral science data (e.g., small to moderate samples, etc.). This paper uses Monte Carlo simulation techniques to examine the performance of these multi-parameter test statistics for multiple imputation under a variety of realistic conditions. We provide a number of practical recommendations for substantive researchers based on the simulation results, and illustrate the calculation of these test statistics with an empirical example.

  15. Ultrasonography and magnetic resonance imaging evaluation of pediatric spinal anomalies

    PubMed Central

    Dhingani, Dhaval Durlabhbhai; Boruah, Deb Kumar; Dutta, Hemonta Kumar; Gogoi, Rudra Kanta

    2016-01-01

    Context: Spinal dysraphisms are congenital abnormalities of the spine due to imperfect fusion of midline mesenchymal, bony and neural structures. Imaging plays a vital role in their evaluation as significant portion of patients may present with concurrent anomalies that need to be corrected simultaneously to avoid repeat surgeries. Aims: The aims of the study were to evaluate Spinal dysraphisms using USG and MRI and to correlate imaging findings with operative findings in patients undergoing surgery. Settings and Design: Hospital based observational study conducted over a period of year. Materials and Methods: 38 cases of both sexes and below 12 years of age with spinal dysraphism were studied. USG was performed in 29 cases where acoustic window was available for proper evaluation. MRI was performed in all cases. USG findings were compared with MRI findings and operative follow up was taken in 23 cases who underwent operative management. Statistical Analysis Used: Results were analysed using percentage and arithmetic mean. Results: 39.47 % cases were male and 60.53 % cases were female. Neonatal period was the most common presenting age group. Closed spinal dysraphism (63.16%) was more common than open (36.84%). 79.31% cases showed full agreement between spinal USG and MRI examinations and 6 out of 20.69% showed partial agreement. On operative correlation, USG findings were confirmatory in 91.30% cases and MRI findings were confirmatory in 100% cases. Conclusions: USG can be used as the initial modality for evaluation of spinal dysraphism as well as for screening of suspected cases. MRI is indicated to confirm abnormal USG findings, which shows all concurrent abnormalities and also provides additional anatomical details relevant to surgical planning. PMID:27857788

  16. Experimental investigations of tuned liquid damper-structure interactions in resonance considering multiple parameters

    NASA Astrophysics Data System (ADS)

    Ashasi-Sorkhabi, Ali; Malekghasemi, Hadi; Ghaemmaghami, Amirreza; Mercan, Oya

    2017-02-01

    As structures are constructed more slender and taller, their vibrational response and its mitigation become challenging design considerations. Tuned liquid dampers (TLDs) are cost effective and low maintenance vibration absorbers that can be used to suppress structural vibrations. A TLD dissipates energy through liquid boundary layer friction, free surface contamination, and wave breaking. The dynamic characteristics of the TLD and its interaction with the structure is quite complex. In this paper, using a state-of-the-art experimental testing method, namely real-time hybrid simulation (RTHS), a comprehensive parametric study is conducted to investigate the effectiveness of TLDs. During RTHS the TLD response is obtained experimentally while the structure is modeled in a computer, thus capturing the TLD-structure interaction in real-time. By keeping the structure as the analytical model, RTHS offers a unique flexibility in which a wide range of influential parameters can be investigated without modifying the experimental setup. The parameters considered in this study with a wide range of variation include TLD/structure mass ratio, TLD/structure frequency ratio, and structural damping ratio. Additionally, the accuracy of FVM/FEM method that couples the finite volume and finite element approaches to model the liquid and solid domains to capture TLD- structure interaction is assessed experimentally. Results obtained in this study, will not only lead to a better understanding of TLDs and their interaction with the structures but also, contribute to the enhanced design of these devices which will in turn result in their wide-spread application.

  17. The far-infrared laser magnetic resonance spectrum of the SiH radical and determination of ground state parameters

    NASA Technical Reports Server (NTRS)

    Brown, J. M.; Curl, R. F.; Evenson, K. M.

    1984-01-01

    The far-infrared laser magnetic resonance spectrum of the SiH radical in the v = O level of its X2Pi state has been recorded. The signals are rather weak. The molecules were generated in the reaction between fluorine atoms and SiH4. Rotational transitions have been detected in both 2Pi1/2 and 2Pi3/2 spin components but no fine structure transitions between the spin components were observed. Proton hyperfine splittings were resolved on some lines. The measurements have been analyzed, subjected to a least-squares fit using an effective Hamiltonian, and the appropriate molecular parameters determined. The weakness of the spectrum and the failure of attempts to power saturate favorable lines are both consistent with a small value for the electric dipole moment for SiH.

  18. Approximating large resonance parameter covariance matrices with group-wise covariance matrices for advanced nuclear fuel cycle applications

    SciTech Connect

    Dunn, Michael E; Leal, Luiz C; Wiarda, Dorothea; Arbanas, Goran

    2008-01-01

    The large size of resonance parameter covariance matrices (RPCM) in the actinide region often renders them impractical for dissemination via ENDF. Therefore, a method of approximating the RPCM by a much smaller group-wise covariance matrix (GWCM) is described, implemented, and examined. In this work, 233U RPCM is used to generate GWCM's for the 44 group AMPX, 100 group GE, 171 group VITAMIN-C, and 240 group CSWEG. Each of these GWCM's is then used to compute group-wise uncertainties for the groups of the remaining group structures. The group-wise uncertainties thus obtained are compared with those obtained from a full RPCM, i.e. without the approximation. A systematic comparison of group-wise uncertainties based on GWCM's vs. RPCM, for a variety of group structures, will shed light on the validity of this approximation and may suggest which group structure(s) yield a GWCM that could be used in lieu of the RPCM.

  19. Effect of constructional parameters on the performance of a surface plasmon resonance sensor based on a multimode polymer optical fiber.

    PubMed

    Gasior, Katarzyna; Martynkien, Tadeusz; Urbanczyk, Waclaw

    2014-12-10

    We experimentally studied the influence of different constructional parameters on the performance of surface plasmon resonance (SPR) sensors based on a commercially available polymer step-index multimode fiber. For the first time, to the best of our knowledge, we experimentally investigated the influence of polishing depth on the characteristics of SPR sensors based on a straight multimode fiber. We also examined the impact of sensing length on the spectral position and strength of the SPR in side-polished straight fibers. To clarify literature contradictions concerning the effect of fiber bending on SPR, we experimentally investigated the performance of U-bent SPR sensing probes based on multimode fibers. We have shown that the SPR can be significantly amplified by bending the polymer fiber with stripped cladding. We also demonstrated that the side-polishing of U-bent sensing probes has little impact on their performance.

  20. Evaluation of performance parameters of indigenously developed roots pumping system

    NASA Astrophysics Data System (ADS)

    Maqsood, M.; Usman, A.; Bodla, M. F.; Ali, J.

    2016-08-01

    Roots pumping systems are widely used in industries to generate vacuum with high pumping speed. In the present work, the performance parameters of indigenously developed Roots pumping system have been studied. The performance parameters being studied are the ultimate pressure, working temperature, compression ratio and pumping speed. Ultimate pressure of the Roots pump after continuous running of eight hours is found to be 1.1x10-3 mbar. The most important parameter of the roots pump is the zero-gas flow compression Ratio (Ko) which is found to be 18 for the pumping system under study. Efficiency of Roots pump is found to be 76% which is in good agreement as reported in the literature.

  1. Extraction of Resonance Parameters and Role of the Final State Interactions

    NASA Astrophysics Data System (ADS)

    Strakovsky, Igor I.; Briscoe, William J.; Kudryavtsev, Alexander E.; Tarasov, Vladimir E.

    2014-01-01

    We present an overview of the SAID group effort to analyze new γn → π-p cross sections vs. the world database to get new multipoles and determine neutron electromagnetic couplings. The differential cross section for the processes γn → π-p was extracted from new measurements at CLAS and MAMI-B accounting for Fermi motion effects in the impulse approximation (IA) as well as NN- and πN-FSI effects beyond the IA. We evaluated results of several pion photoproduction analyses and compared πN PWA results as a constraint for analyses of pion photoproduction data (Watson's theorem).

  2. The Evaluation of the Parameters in the van Deemter Equation.

    ERIC Educational Resources Information Center

    Moody, Harvey W.

    1982-01-01

    Describes experiment expanding on principles behind measuring efficiency of chromatographic columns and allowing calculation of parameters in the van Deemter equation. Easily accomplished in a three-hour period using a gas chromatograph in which gas flow can be changed and measured. Mathematical solutions can be attained with programmable…

  3. Sexual dimorphism in tooth morphometrics: An evaluation of the parameters

    PubMed Central

    Banerjee, Abhishek; Kamath, Venkatesh V.; Satelur, Krishnanand; Rajkumar, Komali; Sundaram, Lavanya

    2016-01-01

    Aims and Objectives: Sexual dimorphism refers to the variations in tooth size and shape between the sexes. The consistency of these variations is valuable in the identification of the sex of an individual in times of mass disaster when whole body parts get destroyed or are unavailable. There exist differences in the expression of these variables across races and regions. This study aims to tabulate and identify the variations in tooth measurements using standarized reference points in an attempt to establish parameters of sexual dimorphism. Materials and Methods: 100 individuals (50 of each sex) in the age group 19-23 years were assessed for standard morphometric parameters of the maxillary central incisor, canine, premolar and molar. Odontometric measurements of established parameters were recorded from impression casts of the maxillary jaws. The mesiodistal width (MDW), the bucco-ligual width (BLW), the crown length (CL) and the cervical angle (CA) were charted among the teeth. The consistency of the variations was statistically analyzed and a logistic regression table was prepared to identify the sex of the individual from the tooth measurements. Results and Conclusions: The BLW, MDW and CL reflected significant variations among all the teeth to be effective in establishing sexual dimorphism. CA as a parameter was inadequate across all the teeth. The permanent maxillary canine was the most important tooth to be reflective of the gender and statistically significant to be utilized for gender determination. PMID:27051219

  4. Evaluation of brain edema using magnetic resonance proton relaxation times

    SciTech Connect

    Fu, Y.; Tanaka, K.; Nishimura, S. )

    1990-01-01

    Experimental and clinical studies on the evaluation of water content in cases of brain edema were performed in vivo, using MR proton relaxation times (longitudinal relaxation time, T1; transverse relaxation time, T2). Brain edema was produced in the white matter of cats by the direct infusion method. The correlations between proton relaxation times obtained from MR images and the water content of white matter were studied both in autoserum-infused cats and in saline-infused cats. The correlations between T1 as well as T2 and the water content in human vasogenic brain edema were also examined and compared with the data obtained from the serum group. T1 and T2 showed good correlations with the water content of white matter not only in the experimental animals but also in the clinical cases. The quality of the edema fluid did not influence relaxation time and T1 seemed to represent almost solely the water content of the tissue. T2, however, was affected by the nature of existence of water and was more sensitive than T1 in detecting extravasated edema fluid. It seems feasible therefore to evaluate the water content of brain edema on the basis of T1 values.

  5. Tabletop magnetic resonance elastography for the measurement of viscoelastic parameters of small tissue samples

    NASA Astrophysics Data System (ADS)

    Ipek-Ugay, Selcan; Drießle, Toni; Ledwig, Michael; Guo, Jing; Hirsch, Sebastian; Sack, Ingolf; Braun, Jürgen

    2015-02-01

    We demonstrate the feasibility of low-cost tabletop MR elastography (MRE) for quantifying the complex shear modulus G∗ of small soft biological tissue samples as provided by pathologists. The MRE system was developed based on a tabletop MRI scanner equipped with a 0.5 T permanent magnet and a tissue sample holder mounted to a loudspeaker. A spin echo sequence was enhanced with motion-encoding gradients of 250 mT/m amplitude synchronized to acoustic vibration frequencies. Shear wave images suitable for elastography were acquired between vibration frequencies of 0.5 and 1 kHz in agarose, ultrasound gel, porcine liver, porcine skeletal muscle, and bovine heart with a spatial resolution of 234 μm pixel edge length. The measured frequency dependence of G∗ agreed well with previous work based on high-field MR systems. The ratio between loss and storage moduli was highest in liver and ultrasound gel, followed by muscle tissue and agarose gel while ultrasound gel and liver showed similarly low storage moduli compared to the other samples. The shear wave to noise ratio is an important imaging criteria for MRE and was about 4.2 times lower for the preliminary setup of the 0.5 T tabletop system compared to a 7 T animal scanner. In the future, the new tabletop MRE system may serve as a low cost device for preclinical research on the correlation of viscoelastic parameters with histopathology of biological samples.

  6. Effects of subcortical cerebrovascular lesions on cortical hemodynamic parameters assessed by perfusion magnetic resonance imaging.

    PubMed

    Nighoghossian, N; Berthezene, Y; Adeleine, P; Wiart, M; Damien, J; Derex, L; Itti, R; Froment, J C; Trouillas, P

    1999-01-01

    A simultaneous decrease of cerebral blood volume (CBV) and cerebral blood flow (CBF) has been described after subcortical stroke with positron emission tomography. However, this imaging modality cannot be applied routinely to stroke patients. Dynamic susceptibility contrast-enhanced MRI techniques (DSC-MRI) might be interesting in the assessment of these effects. Dynamic T2-weighted echo planar imaging was used to produce DSC-MR images during an intravenous bolus injection of gadopentetate dimeglumine in 9 patients who experienced a subcortical stroke involving thalamus or basal ganglia and in 8 control subjects. A series of 50 consecutive images at 1-second intervals was acquired at the anatomic level of the centrum semiovale quite distant from the subcortical lesion, rCBF and rCBV were determined over frontal and parietal regions of interest and through the entire cortical mantle. DSC-MRI enabled the detection of hemodynamic changes induced by subcortical stroke. Analysis of rCBV and rCBF values showed that the hemodynamic parameters were significantly decreased on the affected side. In controls mean rCBF and rCBV values recorded over the whole cortical mantle of each hemisphere showed no significant interhemispheric asymmetry.

  7. Relativistic theory of nuclear magnetic resonance parameters in a Gaussian basis representation

    SciTech Connect

    Kutzelnigg, Werner; Liu Wenjian

    2009-07-28

    The calculation of NMR parameters from relativistic quantum theory in a Gaussian basis expansion requires some care. While in the absence of a magnetic field the expansion in a kinetically balanced basis converges for the wave function in the mean and for the energy with any desired accuracy, this is not necessarily the case for magnetic properties. The results for the magnetizability or the nuclear magnetic shielding are not even correct in the nonrelativistic limit (nrl) if one expands the original Dirac equation in a kinetically balanced Gaussian basis. This defect disappears if one starts from the unitary transformed Dirac equation as suggested by Kutzelnigg [Phys. Rev. A 67, 032109 (2003)]. However, a new difficulty can arise instead if one applies the transformation in the presence of the magnetic field of a point nucleus. If one decomposes certain contributions, the individual terms may diverge, although their sum is regular. A controlled cancellation may become difficult and numerical instabilities can arise. Various ways exist to avoid these singularities and at the same time get the correct nrl. There are essentially three approaches intermediate between the transformed and the untransformed formulation, namely, the bispinor decomposition, the decomposition of the lower component, and the hybrid unitary transformation partially at operator and partially at matrix level. All three possibilities were first considered by Xiao et al. [J. Chem. Phys. 126, 214101 (2007)] in a different context and in a different nomenclature. Their analysis and classification in a more general context are given here for the first time. Use of an extended balanced basis has no advantages and has other drawbacks and is not competitive, while the use of a restricted magnetic balance basis can be justified.

  8. The Evaluation of Empirical Resonance Energies as Reaction Enthalpies with Particular Reference to Benzene.

    ERIC Educational Resources Information Center

    George, Philip; And Others

    1984-01-01

    Discusses the nature of experimental resonance energy, explaining how its magnitude depends upon choice of reference molecules from which bond energies are derived. Also explains how it can be evaluated more simply, without recourse to bond energies, as enthalpy change for a reaction predetermined by choice of reference molecules. (JN)

  9. Noninvasive amide proton transfer magnetic resonance imaging in evaluating the grading and cellularity of gliomas

    PubMed Central

    Zhang, Wei; Kong, Lingfei; Wang, Lifu; Zuo, Panli; Vallines, Ignacio; Schmitt, Benjamin; Tian, Jie; Song, Xiaolei; Zhou, Jinyuan; Wang, Meiyun

    2017-01-01

    Using noninvasive magnetic resonance imaging techniques to accurately evaluate the grading and cellularity of gliomas is beneficial for improving the patient outcomes. Amide proton transfer imaging is a noninvasive molecular magnetic resonance imaging technique based on chemical exchange saturation transfer mechanism that detects endogenous mobile proteins and peptides in biological tissues. Between August 2012 and November 2015, a total number of 44 patients with pathologically proven gliomas were included in this study. We compared the capability of amide proton transfer magnetic resonance imaging with that of noninvasive diffusion-weighted imaging and noninvasive 3-dimensional pseudo-continuous arterial spin imaging in evaluating the grading and cellularity of gliomas. Our results reveal that amide proton transfer magnetic resonance imaging is a superior imaging technique to diffusion-weighted imaging and 3-dimensional pseudo-continuous arterial spin imaging in the grading of gliomas. In addition, our results showed that the Ki-67 index correlated better with the amide proton transfer-weighted signal intensity than with the apparent diffusion coefficient value or the cerebral blood flow value in the gliomas. Amide proton transfer magnetic resonance imaging is a promising method for predicting the grading and cellularity of gliomas. PMID:27992380

  10. Noninvasive amide proton transfer magnetic resonance imaging in evaluating the grading and cellularity of gliomas.

    PubMed

    Bai, Yan; Lin, Yusong; Zhang, Wei; Kong, Lingfei; Wang, Lifu; Zuo, Panli; Vallines, Ignacio; Schmitt, Benjamin; Tian, Jie; Song, Xiaolei; Zhou, Jinyuan; Wang, Meiyun

    2017-01-24

    Using noninvasive magnetic resonance imaging techniques to accurately evaluate the grading and cellularity of gliomas is beneficial for improving the patient outcomes. Amide proton transfer imaging is a noninvasive molecular magnetic resonance imaging technique based on chemical exchange saturation transfer mechanism that detects endogenous mobile proteins and peptides in biological tissues. Between August 2012 and November 2015, a total number of 44 patients with pathologically proven gliomas were included in this study. We compared the capability of amide proton transfer magnetic resonance imaging with that of noninvasive diffusion-weighted imaging and noninvasive 3-dimensional pseudo-continuous arterial spin imaging in evaluating the grading and cellularity of gliomas. Our results reveal that amide proton transfer magnetic resonance imaging is a superior imaging technique to diffusion-weighted imaging and 3-dimensional pseudo-continuous arterial spin imaging in the grading of gliomas. In addition, our results showed that the Ki-67 index correlated better with the amide proton transfer-weighted signal intensity than with the apparent diffusion coefficient value or the cerebral blood flow value in the gliomas. Amide proton transfer magnetic resonance imaging is a promising method for predicting the grading and cellularity of gliomas.

  11. Experimental evaluation of a modal parameter based system identification procedure

    NASA Astrophysics Data System (ADS)

    Yu, Minli; Feng, Ningsheng; Hahn, Eric J.

    2016-02-01

    Correct modelling of the foundation of a rotor bearing foundation system (RBFS) is an invaluable asset for the balancing and efficient running of turbomachinery. Numerical experiments have shown that a modal parameter based identification approach could be feasible for this purpose but there is a lack of experimental verification of the suitability of such a modal approach for even the simplest systems. In this paper the approach is tested on a simple experimental rig comprising a clamped horizontal bar with lumped masses. It is shown that apart from damping, the proposed approach can identify reasonably accurately the relevant modal parameters of the rig; and that the resulting equivalent system can predict reasonably well the frequency response of the rig. Hence, the proposed approach shows promise but further testing is required, since application to identifying the foundation of an RBFS involves the additional problem of accurately obtaining the force excitation from motion measurements.

  12. Thoughts on standardization of parameters for image evaluation

    NASA Technical Reports Server (NTRS)

    Billingsley, F. C.

    1976-01-01

    Images received for image processing and analysis are obtained from a wide variety of sources and with a wide variety of sensors. Because it is desirable to have image processing algorithms be as universally applicable as possible, they should be designed, where possible, to be insensitive to the parametric variations of the source material. Where this is not possible, these variations must be taken into account. Therefore, it is necessary to consider what parameters may be defined in common across a suite of image types. Objective parameters or measurements of images which, in the proper combinations, may serve as surrogates for real images may be pixel-specific, location dependent, or combinations thereof. Parameters which have proven useful in defining the characteristics of images include the gray scale linearity, granularity of the quantization, spectral content, geometrical fidelity, resolution of the system expressed as either the point spread function or the modulation transfer function, and the spatial frequency content and characteristics of the data itself.

  13. The evaluation of radiation damage parameter for CVD diamond

    NASA Astrophysics Data System (ADS)

    Grilj, V.; Skukan, N.; Jakšić, M.; Pomorski, M.; Kada, W.; Kamiya, T.; Ohshima, T.

    2016-04-01

    There are a few different phenomenological approaches that aim to track the dependence of signal height in irradiated solid state detectors on the fluence of damaging particles. However, none of them are capable to provide a unique radiation hardness parameter that would reflect solely the material capability to withstand high radiation environment. To extract such a parameter for chemical vapor deposited (CVD) diamond, two different diamond detectors were irradiated with proton beams in MeV energy range and subjected afterwards to ion beam induced charge (IBIC) analysis. The change in charge collection efficiency (CCE) due to defects produced was investigated in context of a theoretical model that was developed on the basis of the adjoint method for linearization of the continuity equations of electrons and holes. Detailed modeling of measured data resulted with the first known value of the kσ product for diamond, where k represents the number of charge carriers' traps created per one simulated primary lattice vacancy and σ represents the charge carriers' capture cross section. As discussed in the text, this product could be considered as a true radiation damage parameter.

  14. Advanced techniques in magnetic resonance imaging in the evaluation of the large endolymphatic duct and sac syndrome.

    PubMed

    Harnsberger, H R; Dahlen, R T; Shelton, C; Gray, S D; Parkin, J L

    1995-10-01

    The purpose of this report is to compare temporal bone computed tomography (CT) to high-resolution magnetic resonance (MR) imaging using a novel thin-section fast spin echo (FSE) pulse sequence in identifying and characterizing patients with large vestibular aqueduct syndrome. Sixteen patients with sensorineural hearing loss and a CT diagnosis of large vestibular aqueduct(s) underwent high-resolution fast spin echo magnetic resonance imaging with dual, 3-in phased array receiver coils centered over the external auditory canals. Magnetic resonance imaging parameters included axial and oblique sagittal fast spin echo with an effective slice thickness of 1 mm contiguous. Thirty-eight patients with 76 normal inner ears who underwent MR imaging using this technique had their endolymphatic duct measured. MR alone identified the enlarged endolymphatic sac seen along with the large endolymphatic duct in all cases. Three cases (five inner ears) with enlarged bony vestibular aqueducts on CT showed no evidence of endolymphatic duct or sac enlargement on MR. MR alone identified a single case of mild cochlear anomaly in conjunction with an enlarged endolymphatic duct and sac. In the normal population the size of the normal endolymphatic duct at its midpoint measured from 0.1 to 1.4 mm. Thin-section, high-resolution fast spin echo MR imaging of the inner ear may be superior to CT in the evaluation of patients with the large vestibular aqueduct syndrome.

  15. [Comparison of various parameters for determining an index of myocardial perfusion reserve in detecting coronary stenosis with cardiovascular magnetic resonance tomography].

    PubMed

    al-Saadi, N; Gross, M; Bornstedt, A; Schnackenburg, B; Klein, C; Fleck, E; Nagel, E

    2001-11-01

    For the assessment of myocardial perfusion with cardiac magnetic resonance imaging, different semiquantitative parameters of the first pass signal intensity time curves can be calculated and myocardial perfusion reserve indices can be determined. In this study we evaluated the feasibility of different perfusion parameters and their perfusion reserve indices for the detection of significant coronary artery stenosis. The signal intensity time curves of the first pass of a gadolinium-DTPA bolus injected via a central vein catheter before and after dipyridamole infusion were investigated in 15 patients with single vessel (stenosis > or = 75% area reduction) and five patients without significant coronary artery disease. For the distinction of ischemic and nonischemic myocardial segments, semiquantitative parameters, such as maximal signal intensity, contrast appearance time, time to maximal signal intensity and the steepness of the signal intensity curve's upslope determined by a linear fit, were assessed after correction for the input function. For each parameter a myocardial perfusion reserve index was calculated and cut off values for the detection of significant coronary stenosis were defined. The diagnostic accuracy of each parameter was then examined prospectively in 36 patients with coronary artery disease and compared with coronary angiography. Where as a distinction of ischemic and normal myocardium was possible with myocardial perfusion reserve indices, semiquantitative parameters at rest or after vasodilation alone did not allow such a distinction. The perfusion reserve index calculated from the upslope showed the most significant difference between ischemic and nonischemic myocardial segments (1.19 +/- 0.4 and 2.38 +/- 0.45, p < 0.001) followed by maximum signal intensity, time to maximum signal intensity and contrast apperance time. Sensitivity, specificity and diagnostic accuracy was 87, 82 and 85% for the detection of hypoperfusion induced by significant

  16. Quantifying Uranium Isotope Ratios Using Resonance Ionization Mass Spectrometry: The Influence of Laser Parameters on Relative Ionization Probability

    SciTech Connect

    Isselhardt, Brett H.

    2011-09-01

    Resonance Ionization Mass Spectrometry (RIMS) has been developed as a method to measure relative uranium isotope abundances. In this approach, RIMS is used as an element-selective ionization process to provide a distinction between uranium atoms and potential isobars without the aid of chemical purification and separation. We explore the laser parameters critical to the ionization process and their effects on the measured isotope ratio. Specifically, the use of broad bandwidth lasers with automated feedback control of wavelength was applied to the measurement of 235U/238U ratios to decrease laser-induced isotopic fractionation. By broadening the bandwidth of the first laser in a 3-color, 3-photon ionization process from a bandwidth of 1.8 GHz to about 10 GHz, the variation in sequential relative isotope abundance measurements decreased from >10% to less than 0.5%. This procedure was demonstrated for the direct interrogation of uranium oxide targets with essentially no sample preparation. A rate equation model for predicting the relative ionization probability has been developed to study the effect of variation in laser parameters on the measured isotope ratio. This work demonstrates that RIMS can be used for the robust measurement of uranium isotope ratios.

  17. Evaluation of the Physicochemical Parameters of Functional Whey Beverages

    PubMed Central

    Liutkevičius, Algirdas; Sekmokienė, Dalia; Zaborskienė, Gintarė; Šlapkauskaitė, Jūratė

    2015-01-01

    Summary The objective of this study is to determine the impact of the key technological parameters on the quality indices of functional beverages produced from whey and enriched with 0.2% of cold-pressed flaxseed oil, rich in ω-3 fatty acids. The amount of fatty acids, peroxide and anisidine values, fatty acidity, sedimentation and sensory parameters of whey beverages were estimated. It was found that the addition of flaxseed oil affected the sensory, physical and chemical properties of the beverages. High quantities of oleic and α-linolenic fatty acids (18.97 and 54.82%, respectively) and negligible amounts of palmitic and myristic acids (4.79 and 0.04%, respectively) were found in the product. On the basis of the obtained results, the beverages from whey enriched with flaxseed oil had a favourable ratio of n-6/n-3 polyunsaturated fatty acids and atherogenic and thrombogenic indices. The addition of a stabiliser and the pasteurisation of whey beverages with flaxseed oil did not affect the sensory parameters and the acidity of the products. The highest peroxide value (2.36 meq O2/kg) and acidity (0.34%) were found in the samples with pH=4.0 after 30-day storage at (6±1) °С. A strong negative correlation was estimated between the amount of polyunsaturated fatty acids and anisidine value (R=–0.871; p<0.05), peroxide value (R=–0.728; p<0.05) and fatty acidity (R=–0.948; p<0.05). PMID:27904340

  18. Dose-Volume Histogram Parameters and Local Tumor Control in Magnetic Resonance Image-Guided Cervical Cancer Brachytherapy

    SciTech Connect

    Dimopoulos, Johannes Lang, Stefan; Kirisits, Christian; Fidarova, Elena F.; Berger, Daniel; Georg, Petra; Doerr, Wolfgang; Poetter, Richard

    2009-09-01

    Purpose: To investigate the value of dose-volume histogram (DVH) parameters for predicting local control in magnetic resonance (MR) image-guided brachytherapy (IGBT) for patients with cervical cancer. Methods and Materials: Our study population consists of 141 patients with cervical cancer (Stages IB-IVA) treated with 45-50 Gy external beam radiotherapy plus four times 7 Gy IGBT with or without cisplatin. Gross tumor volume (GTV), high-risk clinical target volume (HRCTV), and intermediate-risk clinical target volume (IRCTV) were contoured, and DVH parameters (minimum dose delivered to 90% of the volume of interest [D90] and D100) were assessed. Doses were converted to the equivalent dose in 2 Gy (EQD2) by applying the linear quadratic model ({alpha}/{beta} = 10 Gy). Groups were defined for patients with or without local recurrence (LR) in the true pelvis for tumor size at diagnosis (GTV at diagnosis [GTVD] of 2-5 cm (Group 1) or greater than 5 cm (Group 2) and for tumor size response at IGBT (HRCTV) of 2-5 cm (Group 2a) or greater than 5 cm (Group 2b). Results: Eighteen LRs were observed. The most important DVH parameters correlated with LR were the D90 and D100 for HRCTV. Mean D90 and D100 values for HRCTV were 86 {+-} 16 and 65 {+-} 10 Gy, respectively. The D90 for HRCTV greater than 87 Gy resulted in an LR incidence of 4% (3 of 68) compared with 20% (15 of 73) for D90 less than 87 Gy. The effect was most pronounced in the tumor group (Group 2b). Conclusions: We showed an increase in local control in IGBT in patients with cervical cancer with the dose delivered, which can be expressed by the D90 and D100 for HRCTV. Local control rates greater than 95% can be achieved if the D90 (EQD2) for HRCTV is 87 Gy or greater.

  19. Evaluation of Parameters for High Efficiency Transformation of Acinetobacter baumannii

    PubMed Central

    Yildirim, Suleyman; Thompson, Mitchell G.; Jacobs, Anna C.; Zurawski, Daniel V.; Kirkup, Benjamin C.

    2016-01-01

    Acinetobacter baumannii is an emerging, nosocomial pathogen that is poorly characterized due to a paucity of genetic tools and methods. While whole genome sequence data from several epidemic and environmental strains have recently become available, the functional characterization of genes is significantly lagging. Efficient transformation is one of the first steps to develop molecular tools that can be used to address these shortcomings. Here we report parameters allowing high efficiency transformation of A. baumannii. Using a multi-factorial experimental design we found that growth phase, voltage, and resistance all significantly contribute to transformation efficiency. The highest efficiency (4.3 × 108 Transformants/μg DNA) was obtained at the stationary growth phase of the bacterium (OD 6.0) using 25 ng of plasmid DNA under 100 Ohms resistance and 1.7 kV/cm voltage. The optimized electroporation parameters reported here provide a useful tool for genetic manipulation of A. baumannii. PMID:26911658

  20. Evaluation of physical fitness parameters in patients with schizophrenia.

    PubMed

    Ozbulut, Omer; Genc, Abdurrahman; Bagcioglu, Erman; Coskun, Kerem Senol; Acar, Tolgahan; Alkoc, Ozan Alper; Karabacak, Hatice; Sener, Umit; Ucok, Kagan

    2013-12-30

    The aims of this study were to compare aerobic and anaerobic exercise capacities, pulmonary functions, body composition and fat distribution parameters in patients with schizophrenia and healthy controls and to investigate the associations among these parameters. Sixty (30 male, 30 female) patients with schizophrenia and 60 (30 male, 30 female) healthy controls were included in the study. Maximal aerobic capacity was estimated with the Astrand submaximal exercise protocol, and anaerobic performance was determined with a Wingate test. Body composition was established with a bioelectrical impedance analyzer. Pulmonary function tests, skinfold thickness and body circumference measurements were also carried out. Maximal aerobic capacity, maximal anaerobic power, anaerobic capacity and pulmonary function tests (forced vital capacity and maximal voluntary ventilation) were found to be lower in male and female schizophrenic groups as compared to the controls. Body fat percentage, waist and abdomen circumferences, and waist to hip ratio were found to be higher in female schizophrenic patients than in controls. We suggest that maximal aerobic capacity, maximal anaerobic power, and anaerobic capacity are poor in the schizophrenia patients as compared to healthy controls. Low cardiorespiratory fitness is related to reduced pulmonary function and impaired body composition in schizophrenia patients.

  1. (239)Pu neutron resonance parameters revisited and covariance matrix in the neutron energy range from thermal to 2.5 keV

    SciTech Connect

    Derrien, Herve; Leal, Luiz C; Larson, Nancy M

    2008-01-01

    To obtain the resonance parameters in a single energy range up to 2.5 keV neutron energy and the corresponding covariance matrix, a reevaluation of 239Pu was performed with the analysis code SAMMY. The most recent experimental data were analyzed in the energy range thermal to 2.5 keV. The experimental data were renormalized, aligned on a common energy scale, and corrected for residual background. Average neutron transmission and cross sections calculated with the new resonance parameters were compared to the corresponding experimental data and to ENDF/B-VI.

  2. Nondestructive evaluation of explosively welded clad rods by resonance acoustic spectroscopy.

    PubMed

    Fan, Y; Tysoe, B; Sim, J; Mirkhani, K; Sinclair, A N; Honarvar, F; Sildva, Harry; Szecket, Alexander; Hardwick, Roy

    2003-07-01

    A resonance acoustic spectroscopy technique is assessed for nondestructive evaluation of explosively welded clad rods. Each rod is modeled as a two-layered cylinder with a spring-mass system to represent a thin interfacial layer containing the weld. A range of interfacial profiles is generated in a set of experimental samples by varying the speed of the explosion that drives the copper cladding into the aluminum core. Excellent agreement is achieved between measured and calculated values of the resonant frequencies of the system, through appropriate adjustment of the interfacial mass and spring constants used in the wave scattering calculations. Destructive analysis of the interface in the experimental specimens confirms that key features of the interfacial profile may be inferred from resonance acoustic spectroscopy analysis applied to ultrasonic measurements.

  3. Evaluation parameters for the alkaline fuel cell oxygen electrode

    NASA Technical Reports Server (NTRS)

    Singer, J.; Srinivasan, V.

    1985-01-01

    Studies were made of Pt- and Au-catalyzed porous electrodes, designed for the cathode of the alkaline H2/O2 fuel cell, employing cyclic voltammetry and the floating half-cell method. The purpose was to obtain parameters from the cyclic voltammograms which could predict performance in the fuel cell. It was found that a satisfactory relationship between these two types of measurement could not be established; however, useful observations were made of relative performance of several types of carbon used as supports for noble metal catalysts and of some Au catalysts. The best half-cell performance with H2/O2 in a 35 percent KOH electrolyte at 80 C was given by unsupported fine particle Au on Teflon; this electrode is used in the Orbiter fuel cell.

  4. Evaluating System Parameters on a Dragonfly using Simulation and Visualization

    SciTech Connect

    Bhatele, Abhinav; Jain, Nikhil; Livnat, Yarden; Pascucci, Valerio; Bremer, Peer-Timo

    2015-04-24

    The dragon y topology is becoming a popular choice for build- ing high-radix, low-diameter networks with high-bandwidth links. Even with a powerful network, preliminary experi- ments on Edison at NERSC have shown that for communica- tion heavy applications, job interference and thus presumably job placement remains an important factor. In this paper, we explore the e ects of job placement, job sizes, parallel workloads and network con gurations on network through- put to better understand inter-job interference. We use a simulation tool called Damsel y to model the network be- havior of Edison and study the impact of various system parameters on network throughput. Parallel workloads based on ve representative communication patters are used and the simulation studies on up to 131,072 cores are aided by a new visualization of the dragon y network.

  5. Resonance wood [Picea abies (L.) Karst.]--evaluation and prediction of violin makers' quality-grading.

    PubMed

    Buksnowitz, Christoph; Teischinger, Alfred; Müller, Ulrich; Pahler, Andreas; Evans, Robert

    2007-04-01

    The definition of quality in the field of resonance wood for musical instrument making has attracted considerable interest over decades but has remained incomplete. The current work compares the traditional knowledge and practical experience of violin makers with a material-science approach to objectively characterize the properties of resonance wood. Norway spruce [Picea abies (L.) Karst.] has earned a very high reputation for the construction of resonance tops of stringed instruments and resonance boards of keyboard instruments, and was therefore chosen as the focus of the investigation. The samples were obtained from numerous renowned resonance wood regions in the European Alps and cover the whole range of available qualities. A set of acoustical, anatomical, mechanical and optical material properties was measured on each sample. These measurements were compared with subjective quality grading by violin makers, who estimated the acoustical, optical and overall suitability for violin making. Multiple linear regression models were applied to evaluate the predictability of the subjective grading using the measured material characteristics as predictors. The results show that luthiers are able to estimate wood quality related to visible features, but predictions of mechanical and acoustical properties proved to be very poor.

  6. Modeling of Resonant Ultrasound Spectroscopy Based Nondestructive Evaluation Using the "XYZ-Algorithm"

    SciTech Connect

    Ahmed, Salahuddin; Bond, Leonard J.

    2007-05-03

    Resonant ultrasound spectroscopy (RUS) is employed as a nondestructive evaluation (NDE) tool in a number of metal/ceramic forming industries [1]. The presence of volumetric defects in an otherwise flaw-free object affects the resonance characteristics of the object. The changes in resonance behavior depend on the number, locations, volume, and material properties of the defects. Since the normal modes of an object depend on its geometry and the position-dependent material properties, namely the density and the complex elastic stiffness tensor, by accurate measurement of a specimen’s resonance frequencies and amplitudes, one can detect and characterize flaws embedded within it. A correct forward mathematical model to predict resonance characteristics is vital to the required analyses. In this paper, we present several computational results depicting the influence of the presence of embedded flaws/defects in a test specimen having simple geometrical shape. The mathematical model is based on the computationally efficient “XYZ Algorithm” of Visscher et al.

  7. Criteria for first- and second-order vibrational resonances and correct evaluation of the Darling-Dennison resonance coefficients using the canonical Van Vleck perturbation theory

    SciTech Connect

    Krasnoshchekov, Sergey V.; Isayeva, Elena V.; Stepanov, Nikolay F.

    2014-12-21

    The second-order vibrational Hamiltonian of a semi-rigid polyatomic molecule when resonances are present can be reduced to a quasi-diagonal form using second-order vibrational perturbation theory. Obtaining exact vibrational energy levels requires subsequent numerical diagonalization of the Hamiltonian matrix including the first- and second-order resonance coupling coefficients. While the first-order Fermi resonance constants can be easily calculated, the evaluation of the second-order Darling-Dennison constants requires more complicated algebra for seven individual cases with different numbers of creation-annihilation vibrational quanta. The difficulty in precise evaluation of the Darling-Dennison coefficients is associated with the previously unrecognized interference with simultaneously present Fermi resonances that affect the form of the canonically transformed Hamiltonian. For the first time, we have presented the correct form of the general expression for the evaluation of the Darling-Dennison constants that accounts for the underlying effect of Fermi resonances. The physically meaningful criteria for selecting both Fermi and Darling-Dennison resonances are discussed and illustrated using numerical examples.

  8. Doppler echocardiographic parameters of evaluation of left ventricular systolic function.

    PubMed

    Drăgulescu, S I; Roşu, D; Abazid, J; Ionac, A

    1993-01-01

    The authors suggest a new method using Doppler echocardiography for the evaluation of cardiac performance. Doppler echocardiography permits the calculation of left ventricular (LV) ejection force (according to Newton's second law of motion). The ejection force was calculated in 36 patients with heart failure subgrouped into 3 groups based on ejection fraction (EF) (> 60%; 41-60%; < 40%) compared to 11 normal subjects. The LV ejection force showed a good linear correlation with LV ejection fraction (r = 0.86). Data of the study suggest that the LV ejection force is a valuable and accurate index for the assessment of cardiac performance, especially in early stages of disease.

  9. Contact angle and indentation velocity dependency for a resonance sensor--evaluation on soft tissue silicone models.

    PubMed

    Astrand, Anders P; Jalkanen, Ville; Andersson, Britt M; Lindahl, Olof A

    2013-04-01

    Human tissue stiffness can vary due to different tissue conditions such as cancer tumours. Earlier studies show that stiffness may be detected with a resonance sensor that measures frequency shift and contact force at application. Through the frequency shift and the contact force, a tissue stiffness parameter can be derived. This study evaluated how the probe application angle and indentation velocity affected the results and determined the maximum parameter errors. The evaluation was made on flat silicone discs with specified hardness. The frequency shift, the force and the stiffness parameter all varied with contact angle and indentation velocity. A contact angle of ≤10° was acceptable for reliable measurements. A low indentation velocity was recommended. The maximum errors for the system were <1.1% of the measured values. It was concluded that contact angle and indentation velocity have to be considered in the clinical setting. The angular dependency is especially important in clinical use for studying stiffness of human soft tissue, e.g. in prostate cancer diagnosis.

  10. Evaluation of oxidative and antioxidative parameters in generalized anxiety disorder.

    PubMed

    Emhan, Ali; Selek, Salih; Bayazıt, Hüseyin; Fatih Karababa, İbrahim; Katı, Mahmut; Aksoy, Nurten

    2015-12-30

    Generalized anxiety disorder (GAD) is a prevalent psychiatric disorder. The exact causes of GAD still unknown, in addition to neurochemical and neuroanatomic disorders, genetic and environmental factors are discussed in etiology. In our study we aimed to evaluate the oxidative metabolism's status and investigate the role of oxidative metabolites in GAD. Blood samples were taken from enrolled subjects in appropriate way and total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) were studied in Harran University Biochemistry Labs. Results were compared between groups. The patients' TOS and OSI levels were significantly higher than control group. The patients' TAS levels were significantly lower than controls'. According to our findings, oxidative stress mechanism might have a role in GAD pathophysiology. In the future, total antioxidants may be used as a biologic marker in GAD etiology but more research is needed.

  11. Key Parameters Evaluation for Hip Prosthesis with Finite Element Analysis

    NASA Astrophysics Data System (ADS)

    Guo, Hongqiang; Li, Dichen; Lian, Qin; Li, Xiang; Jin, Zhongmin

    2007-09-01

    Stem length and cross section are two key parameters that influence the stability and longevity of metallic hip prosthesis in the total hip arthroplasty (THA). In order to assess their influence to the stress and fatigue behavior of hip prosthesis, a series model of hip prosthesis with round-shaped or drum-shaped cross section, and with different stem lengths were created. These models were analyzed under both static and dynamic loading conditions with finite element analysis, and dynamic loading represents normal walking was used in the dynamic analysis. The stress on the metallic stem, cement, and adjacent bone were got, micromotion on the cement-metal interface were got too. Safety factors for fatigue life of the hip prothesis were calculated based on data obtained from dynamic analysis. Static analysis shows that drum-shaped cross section can decrease the displacement of the stem, that stress on drum-shaped stem focus on the corner of the femoral neck and the distal part of hip prosthesis, whereas the stress on the round-shaped stem distributes evenly over most part of the stem, and maximum stress on stem prosthesis fluctuates with stem length bottoming out at stem length range from 80 mm to 110 mm, that drum-shaped stems with drum height 8 mm generate more stress at the distal part of stem than drum-shaped stems with drum height 10 mm and round stems do. Dynamic and fatigue analysis shows that drum-shaped stem with drum height 10 mm and stem length 90 mm has the greatest safety factor therefore long fatigue life.

  12. Using prior knowledge in SVD-based parameter estimation for magnetic resonance spectroscopy--the ATP example.

    PubMed

    Stoica, Petre; Selén, Yngve; Sandgren, Niclas; Van Huffel, Sabine

    2004-09-01

    We introduce the knowledge-based singular value decomposition (KNOB-SVD) method for exploiting prior knowledge in magnetic resonance (MR) spectroscopy based on the SVD of the data matrix. More specifically, we assume that the MR data are well modeled by the superposition of a given number of exponentially damped sinusoidal components and that the dampings alphakappa, frequencies omegakappa, and complex amplitudes rhokappa of some components satisfy the following relations: alphakappa = alpha (alpha = unknown), omegakappa = omega + (kappa- 1)delta (omega = unknown, delta = known), and rhokappa = Ckapparho (rho = unknown, ckappa = known real constants). The adenosine triphosphate (ATP) complex, which has one triple peak and two double peaks whose dampings, frequencies, and amplitudes may in some cases be known to satisfy the above type of relations, is used as a vehicle for describing our SVD-based method throughout the paper. By means of numerical examples, we show that our method provides more accurate parameter estimates than a commonly used general-purpose SVD-based method and a previously suggested prior knowledge-based SVD method.

  13. Infrared and far-infrared laser magnetic resonance spectroscopy of the GeH radical - Determination of ground state parameters

    NASA Technical Reports Server (NTRS)

    Brown, J. M.; Evenson, K. M.; Sears, T. J.

    1985-01-01

    The GeH radical has been detected in its ground 2 Pi state in the gas phase reaction of fluorine atoms with GeH4 by laser magnetic resonance techniques. Rotational transitions within both 2 Pi 1/2 and 2 Pi 3/2 manifolds have been observed at far-infrared wavelengths and rotational transitions between the two fine structure components have been detected at infrared wavelengths (10 microns). Signals have been observed for all five naturally occurring isotopes of germanium. Nuclear hyperfine structure for H-1 and Ge-73 has also been observed. The data for the dominant isotope (/Ge-74/H) have been fitted to within experimental error by an effective Hamiltonian to give a set of molecular parameters for the X 2 Pi state which is very nearly complete. In addition, the dipole moment of GeH in its ground state has been estimated from the relative intensities of electric and magnetic dipole transitions in the 10 micron spectrum to be 1.24(+ or - 0.10) D.

  14. TI-205 nuclear magnetic resonance determination of the thermodynamic parameters for the binding of monovalent cations to gramicidins A and C.

    PubMed Central

    Hinton, J F; Fernandez, J Q; Shungu, D C; Whaley, W L; Koeppe, R E; Millett, F S

    1988-01-01

    Thermodynamic parameters for the binding of the monovalent cations, Li+, Na+, K+, Rb+, Cs+, NH4+, TI+, and Ag+, to gramicidin A and for the binding of TI+ to gramicidin C, incorporated into lysophosphatidylcholine, have been determined using a combination of TI-205 nuclear magnetic resonance spectroscopy and competition binding. The thermodynamic parameters, enthalpy and entropy, are discussed in terms of a process involving the transfer of cations from an aqueous to amide environment. PMID:2462930

  15. Update on Magnetic Resonance Imaging and Ultrasound Evaluation of Crohn’s Disease

    PubMed Central

    Deepak, Parakkal; Kolbe, Amy B.; Fidler, Jeff L.; Fletcher, Joel G.; Knudsen, John M.

    2016-01-01

    Magnetic resonance enterography (MRE) and abdominal ultrasound are integral parts of multimodality assessments for patients with inflammatory bowel disease. Applications include assessing Crohn’s disease (CD) extent and severity, differentiating CD from ulcerative colitis, detecting CD complications, evaluating response to therapy, and demonstrating postoperative recurrence. Magnetic resonance imaging protocols are being developed that may reduce or eliminate the need for intravenous contrast agents and better differentiate inflammatory from fibrotic strictures. MRE scoring systems have been created to objectively quantify disease activity and response to therapy. By utilizing advanced sonographic imaging techniques, including ultrasound contrast and Doppler assessments, the role of abdominal ultrasonography in the evaluation and management of CD continues to expand. Abdominal ultrasound may function as a low-cost, point-of care assessment tool, especially in CD restricted to the terminal ileum and ileocolic anastomosis. PMID:27231453

  16. Fluctuations Above the Resonance Range in Evaluated Data of 55Mn

    NASA Astrophysics Data System (ADS)

    Trkov, A.; Capote, R.; Leal, L. C.; Muir, D. W.; Soukhovitskiı˜, E. Sh.

    2014-04-01

    The evaluation procedures for 55Mn are elaborated, focusing on the issues related to the fluctuations in the cross sections above the resolved resonance range. Smooth cross sections are defined in the unresolved resonance range, based on the resolution-broadened total cross section measurements, where relevant. Above this energy fluctuations in the measured total cross section are introduced by scaling all reaction cross sections, but preserving the resolution-broadened total cross section. Special procedures are designed to match the observed structure in the average cosine of scattering by adjusting the ratio of the shape-elastic and compound-elastic contributions to the elastic scattering cross sections. The evaluated data file is being assembled and subjected to rigorous testing, verification and validation.

  17. Application of Advanced Magnetic Resonance Imaging Techniques in Evaluation of the Lower Extremity

    PubMed Central

    Braun, Hillary J.; Dragoo, Jason L.; Hargreaves, Brian A.; Levenston, Marc E.; Gold, Garry E.

    2012-01-01

    Synopsis This article reviews current magnetic resonance imaging techniques for imaging the lower extremity, focusing on imaging of the knee, ankle, and hip joints. Recent advancements in MRI include imaging at 7 Tesla, using multiple receiver channels, T2* imaging, and metal suppression techniques, allowing more detailed visualization of complex anatomy, evaluation of morphological changes within articular cartilage, and imaging around orthopedic hardware. PMID:23622097

  18. White LED compared with other light sources: age-dependent photobiological effects and parameters for evaluation.

    PubMed

    Rebec, Katja Malovrh; Klanjšek-Gunde, Marta; Bizjak, Grega; Kobav, Matej B

    2015-01-01

    Ergonomic science at work and living places should appraise human factors concerning the photobiological effects of lighting. Thorough knowledge on this subject has been gained in the past; however, few attempts have been made to propose suitable evaluation parameters. The blue light hazard and its influence on melatonin secretion in age-dependent observers is considered in this paper and parameters for its evaluation are proposed. New parameters were applied to analyse the effects of white light-emitting diode (LED) light sources and to compare them with the currently applied light sources. The photobiological effects of light sources with the same illuminance but different spectral power distribution were determined for healthy 4-76-year-old observers. The suitability of new parameters is discussed. Correlated colour temperature, the only parameter currently used to assess photobiological effects, is evaluated and compared to new parameters.

  19. Acute Cardiac Impairment Associated With Concurrent Chemoradiotherapy for Esophageal Cancer: Magnetic Resonance Evaluation

    SciTech Connect

    Hatakenaka, Masamitsu; Yonezawa, Masato; Nonoshita, Takeshi; Nakamura, Katsumasa; Yabuuchi, Hidetake; Shioyama, Yoshiyuki; Nagao, Michinobu; Matsuo, Yoshio; Kamitani, Takeshi; Higo, Taiki; Nishikawa, Kei; Setoguchi, Taro; Honda, Hiroshi

    2012-05-01

    Purpose: To evaluate acute cardiac effects of concurrent chemoradiotherapy (CCRT) for esophageal cancer. Methods and Materials: This prospective study was approved by the institutional review board, and written informed consent was obtained from all participants. The left ventricular function (LVF) of 31 patients with esophageal cancer who received cisplatin and 5-fluorouracil-based CCRT was evaluated using cardiac cine magnetic resonance imaging. The patients were classified into two groups according to mean LV dose. The parameters related to LVF were compared between before and during (40 Gy) or between before and after CCRT using a Wilcoxon matched-pairs single rank test, and parameter ratios (during/before CCRT, after/before CCRT) were also compared between the groups with a t test. Data were expressed as mean {+-} SE. Results: In the low LV-dose group (n = 10; mean LV dose <0.6 Gy), LV ejection fraction decreased significantly (before vs. during vs. after CCRT; 62.7% {+-} 2.98% vs. 59.8% {+-} 2.56% vs. 60.6% {+-} 3.89%; p < 0.05). In the high LV-dose group (n = 21; mean LV dose of 3.6-41.2 Gy), LV end-diastolic volume index (before vs. after CCRT; 69.1 {+-} 2.93 vs. 57.0 {+-} 3.23 mL/m{sup 2}), LV stroke volume index (38.6 {+-} 1.56 vs. 29.9 {+-} 1.60 mL/m{sup 2}), and LV ejection fraction (56.9% {+-} 1.79% vs. 52.8% {+-} 1.15%) decreased significantly (p < 0.05) after CCRT. Heart rate increased significantly (before vs. during vs. after CCRT; 66.8 {+-} 3.05 vs. 72.4 {+-} 4.04 vs. 85.4 {+-} 3.75 beats per minute, p < 0.01). Left ventricle wall motion decreased significantly (p < 0.05) in segments 8 (before vs. during vs. after CCRT; 6.64 {+-} 0.54 vs. 4.78 {+-} 0.43 vs. 4.79 {+-} 0.50 mm), 9 (6.88 {+-} 0.45 vs. 5.04 {+-} 0.38 vs. 5.27 {+-} 0.47 mm), and 10 (9.22 {+-} 0.48 vs. 8.08 {+-} 0.34 vs. 8.19 {+-} 0.56 mm). The parameter ratios of LV end-diastolic volume index, stroke volume index, wall motion in segment 9, and heart rate showed significant difference

  20. Utility of magnetic resonance imaging in the evaluation of left ventricular thickening.

    PubMed

    Fulton, Nicholas; Rajiah, Prabhakar

    2017-04-01

    Left ventricular (LV) thickening can be due to hypertrophy (concentric, asymmetric, eccentric) or remodelling (concentric or asymmetric). Pathological thickening may be caused by pressure overload, volume overload, infiltrative disorders, hypertrophic cardiomyopathy, athlete's heart or neoplastic infiltration. Magnetic resonance imaging (MRI) plays an important role in the comprehensive evaluation of LV thickening, including: establishing diagnosis, determining LV geometry, establishing aetiology, quantification, identifying prognostic factors, serial follow-up and treatment response. In this article, we review the aetiologies and pathophysiology of LV thickening, and demonstrate the comprehensive role of MRI in the evaluation of LV thickening.

  1. Evaluation of kinetic constants of biomolecular interaction on optical surface plasmon resonance sensor with Newton Iteration Method

    NASA Astrophysics Data System (ADS)

    Zhao, Yuanyuan; Jiang, Guoliang; Hu, Jiandong; Hu, Fengjiang; Wei, Jianguang; Shi, Liang

    2010-10-01

    In the immunology, there are two important types of biomolecular interaction: antigens-antibodies and receptors-ligands. Monitoring the response rate and affinity of biomolecular interaction can help analyze the protein function, drug discover, genomics and proteomics research. Moreover the association rate constant and dissociation rate constant of receptors-ligands are the important parameters for the study of signal transmission between cells. Recent advances in bioanalyzer instruments have greatly simplified the measurement of the kinetics of molecular interactions. Non-destructive and real-time monitoring the response to evaluate the parameters between antigens and antibodies can be performed by using optical surface plasmon resonance (SPR) biosensor technology. This technology provides a quantitative analysis that is carried out rapidly with label-free high-throughput detection using the binding curves of antigens-antibodies. Consequently, the kinetic parameters of interaction between antigens and antibodies can be obtained. This article presents a low cost integrated SPR-based bioanalyzer (HPSPR-6000) designed by ourselves. This bioanalyzer is mainly composed of a biosensor TSPR1K23, a touch-screen monitor, a microprocessor PIC24F128, a microflow cell with three channels, a clamp and a photoelectric conversion device. To obtain the kinetic parameters, sensorgrams may be modeled using one of several binding models provided with BIAevaluation software 3.0, SensiQ or Autolab. This allows calculation of the association rate constant (ka) and the dissociation rate constant (kd). The ratio of ka to kd can be used to estimate the equilibrium constant. Another kind is the analysis software OriginPro, which can process the obtained data by nonlinear fitting and then get some correlative parameters, but it can't be embedded into the bioanalyzer, so the bioanalyzer don't support the use of OriginPro. This paper proposes a novel method to evaluate the kinetic parameters

  2. Dose-Volume Histogram Parameters and Late Side Effects in Magnetic Resonance Image-Guided Adaptive Cervical Cancer Brachytherapy

    SciTech Connect

    Georg, Petra; Lang, Stefan; Dimopoulos, Johannes C.A.; Doerr, Wolfgang; Sturdza, Alina E.; Berger, Daniel; Georg, Dietmar; Kirisits, Christian; Poetter, Richard

    2011-02-01

    Purpose: To evaluate the predictive value of dose-volume histogram (DVH) parameters for late side effects of the rectum, sigmoid colon, and bladder in image-guided brachytherapy for cervix cancer patients. Methods and Materials: A total of 141 patients received external-beam radiotherapy and image-guided brachytherapy with or without chemotherapy. The DVH parameters for the most exposed 2, 1, and 0.1 cm{sup 3} (D{sub 2cc}, D{sub 1cc}, and D{sub 0.1cc}) of the rectum, sigmoid, and bladder, as well as International Commission on Radiation Units and Measurements point doses (D{sub ICRU}) were computed. Total doses were converted to equivalent doses in 2 Gy by applying the linear-quadratic model ({alpha}/{beta} = 3 Gy). Late side effects were prospectively assessed using the Late Effects in Normal Tissues-Subjective, Objective, Management and Analytic score. The following patient groups were defined: Group 1: no side effects (Grade 0); Group 2: side effects (Grade 1-4); Group 3: minor side effects (Grade 0-1); and Group 4: major side effects (Grade 2-4). Results: The median follow-up was 51 months. The overall 5-year actuarial side effect rates were 12% for rectum, 3% for sigmoid, and 23% for bladder. The mean total D{sub 2cc} were 65 {+-} 12 Gy for rectum, 62 {+-} 12 Gy for sigmoid, and 95 {+-} 22 Gy for bladder. For rectum, statistically significant differences were observed between Groups 1 and 2 in all DVH parameters and D{sub ICRU}. Between Groups 3 and 4, no difference was observed for D{sub 0.1cc.} For sigmoid, significant differences were observed for D{sub 2cc} and D{sub 1cc}, but not for D{sub 0.1cc} in all groups. For bladder, significant differences were observed for all DVH parameters only comparing Groups 3 and 4. No differences were observed for D{sub ICRU}. Conclusions: The parameters D{sub 2cc} and D{sub 1cc} have a good predictive value for rectal toxicity. For sigmoid, no prediction could be postulated because of limited data. In bladder, DVH

  3. Profiles of ion beams and plasma parameters on a multi-frequencies microwaves large bore electron cyclotron resonance ion source with permanent magnets.

    PubMed

    Kato, Yushi; Sakamoto, Naoki; Kiriyama, Ryutaro; Takenaka, Tomoya; Kurisu, Yosuke; Nozaki, Dai; Sato, Fuminobu; Iida, Toshiyuki

    2012-02-01

    In order to contribute to various applications of plasma and beams based on an electron cyclotron resonance, a new concept on magnetic field with all magnets on plasma production and confinement has been proposed with enhanced efficiency for broad and dense ion beam. The magnetic field configuration consists of a pair of comb-shaped magnet surrounding plasma chamber cylindrically. Resonance zones corresponding for 2.45 GHz and 11-13 GHz frequencies are positioned at spatially different positions. We launch simultaneously multiplex frequencies microwaves operated individually, try to control profiles of the plasma parameters and the extracted ion beams, and to measure them in detail.

  4. Profiles of ion beams and plasma parameters on a multi-frequencies microwaves large bore electron cyclotron resonance ion source with permanent magnets

    SciTech Connect

    Kato, Yushi; Sakamoto, Naoki; Kiriyama, Ryutaro; Takenaka, Tomoya; Kurisu, Yosuke; Nozaki, Dai; Sato, Fuminobu; Iida, Toshiyuki

    2012-02-15

    In order to contribute to various applications of plasma and beams based on an electron cyclotron resonance, a new concept on magnetic field with all magnets on plasma production and confinement has been proposed with enhanced efficiency for broad and dense ion beam. The magnetic field configuration consists of a pair of comb-shaped magnet surrounding plasma chamber cylindrically. Resonance zones corresponding for 2.45 GHz and 11-13 GHz frequencies are positioned at spatially different positions. We launch simultaneously multiplex frequencies microwaves operated individually, try to control profiles of the plasma parameters and the extracted ion beams, and to measure them in detail.

  5. Evaluation of Soft Tissue Sarcoma Response to Preoperative Chemoradiotherapy Using Dynamic Contrast-Enhanced Magnetic Resonance Imaging

    PubMed Central

    Huang, Wei; Beckett, Brooke R.; Tudorica, Alina; Meyer, Janelle M.; Afzal, Aneela; Chen, Yiyi; Mansoor, Atiya; Hayden, James B.; Doung, Yee-Cheen; Hung, Arthur Y.; Holtorf, Megan L.; Aston, Torrie J.; Ryan, Christopher W.

    2016-01-01

    This study aims to assess the utility of quantitative dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) parameters in comparison with imaging tumor size for early prediction and evaluation of soft tissue sarcoma response to preoperative chemoradiotherapy. In total, 20 patients with intermediate- to high-grade soft tissue sarcomas received either a phase I trial regimen of sorafenib + chemoradiotherapy (n = 8) or chemoradiotherapy only (n = 12), and underwent DCE-MRI at baseline, after 2 weeks of treatment with sorafenib or after the first chemotherapy cycle, and after therapy completion. MRI tumor size in the longest diameter (LD) was measured according to the RECIST (Response Evaluation Criteria In Solid Tumors) guidelines. Pharmacokinetic analyses of DCE-MRI data were performed using the Shutter-Speed model. After only 2 weeks of treatment with sorafenib or after 1 chemotherapy cycle, Ktrans (rate constant for plasma/interstitium contrast agent transfer) and its percent change were good early predictors of optimal versus suboptimal pathological response with univariate logistic regression C statistics values of 0.90 and 0.80, respectively, whereas RECIST LD percent change was only a fair predictor (C = 0.72). Post-therapy Ktrans, ve (extravascular and extracellular volume fraction), and kep (intravasation rate constant), not RECIST LD, were excellent (C > 0.90) markers of therapy response. Several DCE-MRI parameters before, during, and after therapy showed significant (P < .05) correlations with percent necrosis of resected tumor specimens. In conclusion, absolute values and percent changes of quantitative DCE-MRI parameters provide better early prediction and evaluation of the pathological response of soft tissue sarcoma to preoperative chemoradiotherapy than the conventional measurement of imaging tumor size change. PMID:28066805

  6. Magnetic resonance imaging of the chest in the evaluation of cancer patients: state of the art

    PubMed Central

    Guimaraes, Marcos Duarte; Hochhegger, Bruno; Santos, Marcel Koenigkam; Santana, Pablo Rydz Pinheiro; Sousa, Arthur Soares; Souza, Luciana Soares; Marchiori, Edson

    2015-01-01

    Magnetic resonance imaging (MRI) has several advantages in the evaluation of cancer patients with thoracic lesions, including involvement of the chest wall, pleura, lungs, mediastinum, esophagus and heart. It is a quite useful tool in the diagnosis, staging, surgical planning, treatment response evaluation and follow-up of these patients. In the present review, the authors contextualize the relevance of MRI in the evaluation of thoracic lesions in cancer patients. Considering that MRI is a widely available method with high contrast and spatial resolution and without the risks associated with the use of ionizing radiation, its use combined with new techniques such as cine-MRI and functional methods such as perfusion- and diffusion-weighted imaging may be useful as an alternative tool with performance comparable or complementary to conventional radiological methods such as radiography, computed tomography and PET/CT imaging in the evaluation of patients with thoracic neoplasias. PMID:25798006

  7. Magnetic resonance imaging of the chest in the evaluation of cancer patients: state of the art.

    PubMed

    Guimaraes, Marcos Duarte; Hochhegger, Bruno; Santos, Marcel Koenigkam; Santana, Pablo Rydz Pinheiro; Sousa, Arthur Soares; Souza, Luciana Soares; Marchiori, Edson

    2015-01-01

    Magnetic resonance imaging (MRI) has several advantages in the evaluation of cancer patients with thoracic lesions, including involvement of the chest wall, pleura, lungs, mediastinum, esophagus and heart. It is a quite useful tool in the diagnosis, staging, surgical planning, treatment response evaluation and follow-up of these patients. In the present review, the authors contextualize the relevance of MRI in the evaluation of thoracic lesions in cancer patients. Considering that MRI is a widely available method with high contrast and spatial resolution and without the risks associated with the use of ionizing radiation, its use combined with new techniques such as cine-MRI and functional methods such as perfusion- and diffusion-weighted imaging may be useful as an alternative tool with performance comparable or complementary to conventional radiological methods such as radiography, computed tomography and PET/CT imaging in the evaluation of patients with thoracic neoplasias.

  8. Evaluation of measures of technical image quality for intracranial magnetic resonance angiography.

    PubMed

    Chapman, B E; Goodrich, C K; Alexander, A L; Blatter, D D; Parker, D L

    1999-12-01

    We evaluate three measures of technical image quality for intracranial magnetic resonance angiography (MRA): (1) a two-alternative forced choice (2AFC) evaluation of vessel visibility, (2) vessel-to-background signal-difference-to-noise ratio (SDNR), and (3) observer ranking of the fidelity of vessel morphology compared to that in a gold standard image. The gold standard used for both the 2AFC and ranking measures is intraarterial catheter angiography. These measures are applied to healthy arterial segments. The 2AFC and SDNR measures directly evaluate the visibility of artery segments for which the existence is known from the gold standard images. We argue that (1) 2AFC evaluates the carrier signals on which any vascular disease process is modulated and provides an upper bound on the detectibility of vascular lesions, (2) SDNR is a predictor of 2AFC, and (3) ranking may be used to predict the relative performance of techniques in the detection of vascular lesions.

  9. BUILDING MODEL ANALYSIS APPLICATIONS WITH THE JOINT UNIVERSAL PARAMETER IDENTIFICATION AND EVALUATION OF RELIABILITY (JUPITER) API

    EPA Science Inventory

    The open-source, public domain JUPITER (Joint Universal Parameter IdenTification and Evaluation of Reliability) API (Application Programming Interface) provides conventions and Fortran-90 modules to develop applications (computer programs) for analyzing process models. The input ...

  10. A COMPUTATIONAL FRAMEWORK FOR EVALUATION OF NPS MANAGEMENT SCENARIOS: ROLE OF PARAMETER UNCERTAINTY

    EPA Science Inventory

    Utility of complex distributed-parameter watershed models for evaluation of the effectiveness of non-point source sediment and nutrient abatement scenarios such as Best Management Practices (BMPs) often follows the traditional {calibrate ---> validate ---> predict} procedure. Des...

  11. Instrumental Dependent Dissociations of n-Propyl/Isopropyl Phosphonate Isomers: Evaluation of Resonant and Non-Resonant Vibrational Activations

    NASA Astrophysics Data System (ADS)

    Bennaceur, Chafia; Afonso, Carlos; Alves, Sandra; Bossée, Anne; Tabet, Jean-Claude

    2013-08-01

    Structural elucidation and distinction of isomeric neurotoxic agents remain a challenge. Tandem mass spectrometry can be used for this purpose in particular if a "diagnostic" product ion is observed. Different vibrational activation methods were investigated to enhance formation of diagnostic ions through consecutive processes from O,O-dialkyl alkylphosphonates. Resonant and non-resonant collisional activation and infrared multiphoton dissociation (IRMPD) were used with different mass spectrometers: a hybrid quadrupole Fourier transform ion cyclotron resonance (Qh-FTICR) and a hybrid linear ion trap-Orbitrap (LTQ/Orbitrap). Double resonance (DR) experiments, in ion cyclotron resonance (ICR) cell, were used for unambiguous determination of direct intermediate yielding diagnostic ions. From protonated n-propyl and isopropyl O-O-dialkyl-phosphonates, a diagnostic m/ z 83 ion characterizes the isopropyl isomer. This ion is produced through consecutive dissociation processes. Conditions to favor its formation and observation using different activation methods were investigated. It was shown that with the LTQ, consecutive experimental steps of isolation/activation with modified trapping conditions limiting the low mass cut off (LMCO) effect were required, whereas with FT-ICR by CID and IRMPD the diagnostic ion detection was provided only by one activation step. Among the different investigated activation methods it was shown that by using low-pressure conditions or using non-resonant methods, efficient and fast differentiation of isomeric neurotoxic agents was obtained. This work constitutes a unique comparison of different activation modes for distinction of isomers showing the instrumental dependence characteristic of the consecutive processes. New insights in the dissociation pathways were obtained based on double-resonance IRMPD experiments using a FT-ICR instrument with limitation at low mass values.

  12. Instrumental dependent dissociations of n-propyl/isopropyl phosphonate isomers: evaluation of resonant and non-resonant vibrational activations.

    PubMed

    Bennaceur, Chafia; Afonso, Carlos; Alves, Sandra; Bossée, Anne; Tabet, Jean-Claude

    2013-08-01

    Structural elucidation and distinction of isomeric neurotoxic agents remain a challenge. Tandem mass spectrometry can be used for this purpose in particular if a "diagnostic" product ion is observed. Different vibrational activation methods were investigated to enhance formation of diagnostic ions through consecutive processes from O,O-dialkyl alkylphosphonates. Resonant and non-resonant collisional activation and infrared multiphoton dissociation (IRMPD) were used with different mass spectrometers: a hybrid quadrupole Fourier transform ion cyclotron resonance (Qh-FTICR) and a hybrid linear ion trap-Orbitrap (LTQ/Orbitrap). Double resonance (DR) experiments, in ion cyclotron resonance (ICR) cell, were used for unambiguous determination of direct intermediate yielding diagnostic ions. From protonated n-propyl and isopropyl O-O-dialkyl-phosphonates, a diagnostic m/z 83 ion characterizes the isopropyl isomer. This ion is produced through consecutive dissociation processes. Conditions to favor its formation and observation using different activation methods were investigated. It was shown that with the LTQ, consecutive experimental steps of isolation/activation with modified trapping conditions limiting the low mass cut off (LMCO) effect were required, whereas with FT-ICR by CID and IRMPD the diagnostic ion detection was provided only by one activation step. Among the different investigated activation methods it was shown that by using low-pressure conditions or using non-resonant methods, efficient and fast differentiation of isomeric neurotoxic agents was obtained. This work constitutes a unique comparison of different activation modes for distinction of isomers showing the instrumental dependence characteristic of the consecutive processes. New insights in the dissociation pathways were obtained based on double-resonance IRMPD experiments using a FT-ICR instrument with limitation at low mass values.

  13. Evaluation of toroidal torque by non-resonant magnetic perturbations in tokamaks for resonant transport regimes using a Hamiltonian approach

    NASA Astrophysics Data System (ADS)

    Albert, Christopher G.; Heyn, Martin F.; Kapper, Gernot; Kasilov, Sergei V.; Kernbichler, Winfried; Martitsch, Andreas F.

    2016-08-01

    Toroidal torque generated by neoclassical viscosity caused by external non-resonant, non-axisymmetric perturbations has a significant influence on toroidal plasma rotation in tokamaks. In this article, a derivation for the expressions of toroidal torque and radial transport in resonant regimes is provided within quasilinear theory in canonical action-angle variables. The proposed approach treats all low-collisional quasilinear resonant neoclassical toroidal viscosity regimes including superbanana-plateau and drift-orbit resonances in a unified way and allows for magnetic drift in all regimes. It is valid for perturbations on toroidally symmetric flux surfaces of the unperturbed equilibrium without specific assumptions on geometry or aspect ratio. The resulting expressions are shown to match the existing analytical results in the large aspect ratio limit. Numerical results from the newly developed code NEO-RT are compared to calculations by the quasilinear version of the code NEO-2 at low collisionalities. The importance of the magnetic shear term in the magnetic drift frequency and a significant effect of the magnetic drift on drift-orbit resonances are demonstrated.

  14. Appearance of monoclonal plasma cell diseases in whole-body magnetic resonance imaging and correlation with parameters of disease activity.

    PubMed

    Kloth, Jost K; Hillengass, Jens; Listl, Karin; Kilk, Kerstin; Hielscher, Thomas; Landgren, Ola; Delorme, Stefan; Goldschmidt, Hartmut; Kauczor, Hans-Ulrich; Weber, Marc-André

    2014-11-15

    The aim of our study was to assess in which way different infiltration patterns of monoclonal plasma cell diseases in whole-body (wb) magnetic resonance imaging (MRI) are associated with clinical stages, plasma cell content in bone marrow samples and established serum markers of disease activity. Institutional review board approval was obtained. We performed wb-MRI in 547 consecutive, unselected and untreated patients with monoclonal gammopathy of undetermined significance (MGUS, n=138), smoldering myeloma (SMM, n=157) and multiple myeloma (MM, n=252) on two 1.5 T MRI-scanners with body array coils. The studies were evaluated in consensus by two experienced radiologists blinded to the diagnosis. We observed focal lesions in 23.9% (MGUS), 34.4% (SMM) and 81.3% (MM), respectively. A diffuse infiltration pattern was detected in 38.4%, 45.9% and 71%, respectively. The differences between all infiltration patterns were significant (p<0.0001). The presence of focal lesions and the presence of a diffuse bone marrow infiltration was associated with an increased plasma cell percentage in bone marrow samples (median 22% vs. 14%, 26% vs. 10%, both p<0.0001) and monoclonal protein concentration (median 18 g/dl vs. 13 g/dl, p=0.003, 20 g/dl vs. 11 g/dl, p<0.0001). Further categorization of the diffuse infiltration patterns in wb-MRI into "salt-and-pepper," moderate and severe identified significant associations with M-protein (median g/dl for S+P/moderate/severe 23/18/25, p=0.04), plasma cell percentage in the bone marrow (median 25%/24%/40%, p=0.02), and age (median years 67/60/57, p<0.0001). Bone marrow infiltration in wb-MRI is significantly different between the various stages of plasma cell disease and correlates well with established markers of disease activity.

  15. Role of magnetic resonance spectroscopy in evaluation of congenital/developmental brain abnormalities.

    PubMed

    Shekdar, Karuna; Wang, Dah-Jyuu

    2011-12-01

    Magnetic resonance spectroscopy (MRS) is an invaluable tool to study brain development and in vivo metabolism of brain. MRS is a noninvasive method and also does not involve ionizing radiation. The spectral patterns obtained from MRS evaluation provide unique information about the neonatal brain in several disease processes including hypoxic-ischemic injury, white matter and metabolic disorders, seizure disorders, and brain tumors. MRS also provides quantitative information about specific metabolites that is useful in the diagnosis and in evaluating treatment response of the disease. This discussion is limited to the use of MRS in evaluation of congenital or developmental brain abnormalities. The discussion of clinical utility of MRS is preceded by a brief overview of the technical aspects of MRS, followed by description of normal brain spectra in the neonates and the changes with normal brain development.

  16. Cine-magnetic resonance imaging evaluation of communication between middle cranial fossa arachnoid cysts and cisterns.

    PubMed

    Eguchi, T; Taoka, T; Nikaido, Y; Shiomi, K; Fujimoto, T; Otsuka, H; Takeuchi, H

    1996-06-01

    Cine-magnetic resonance (MR) imaging examinations were performed in 10 patients with middle cranial fossa arachnoid cysts to evaluate communication between the cysts and the normal cerebrospinal fluid (CSF) space. Eight of 10 patients were evaluated by time of flight cine-MR imaging, and two by phase contrast cine-MR imaging. Two patients underwent membranectomy of the cysts, and were evaluated both pre- and postoperatively. Computed tomography cisternography was used to confirm communication between the cysts and the surrounding cisterns. Pulsatile fluid motion within the cysts was present in all patients. However, marked fluid motion and jet flow between the cysts and the surrounding cisterns were only observed in communicating cysts. In the two patients who underwent membranectomy, postoperative examination found greater fluid motion and jet flow not previously present. Cine-MR imaging demonstration of marked pulsatile fluid motion accompanied by jet flow suggests that a cyst communicates with the normal CSF space.

  17. Recent results of the parameters A and R measurements in the resonance region of the {pi}N-elastic scattering and subsequent investigations

    SciTech Connect

    Sumachev, V. V.; Beloglazov, Yu. A.; Filimonov, E. A.; Kovalev, A. I.; Kozlenko, N. G.; Kruglov, S. P.; Kulbardis, A. A.; Lopatin, I. V.; Novinsky, D. V.; Shchedrov, V. A.; Trautman, V. Yu.; Alekseev, I. G.; Budkovsky, P. E.; Kanavets, V. P.; Koroleva, L. I.; Morozov, B. V.; Nesterov, V. M.; Ryltsov, V. V.; Sulimov, A. D.; Svirida, D. N.

    2008-10-13

    The existing models of baryons usually predict considerably more resonance (three or more in number) than it was found by investigation of elastic pion-nucleon scattering. This disagreement invites further investigation of the pion-nucleon interaction and among other things the measurement of spin rotation parameters A and R in the elastic pion-nucleon scattering.Recent experiments of the PNPI and PNPI-ITEP collaborations resolved a part of twofold ambiguities of the existing partial wave analyses (PWA). These results were used in the last PWA of the George Washington University group SP06. The proposal for the additional spin rotation parameters A and R measurement in the resonance region is motivated. Such additional measurements are necessary to resolve remaining twofold ambiguities of the existing PWAs.

  18. Forward models for extending the mechanical damage evaluation capability of resonant ultrasound spectroscopy.

    PubMed

    Goodlet, B R; Torbet, C J; Biedermann, E J; Jauriqui, L M; Aldrin, J C; Pollock, T M

    2017-02-08

    Finite element (FE) modeling has been coupled with resonant ultrasound spectroscopy (RUS) for nondestructive evaluation (NDE) of high temperature damage induced by mechanical loading. Forward FE models predict mode-specific changes in resonance frequencies (ΔfR), inform RUS measurements of mode-type, and identify diagnostic resonance modes sensitive to individual or multiple concurrent damage mechanisms. The magnitude of modeled ΔfR correlate very well with the magnitude of measured ΔfR from RUS, affording quantitative assessments of damage. This approach was employed to study creep damage in a polycrystalline Ni-based superalloy (Mar-M247) at 950°C. After iterative applications of creep strains up to 8.8%, RUS measurements recorded ΔfR that correspond to the accumulation of plastic deformation and cracks in the gauge section of a cylindrical dog-bone specimen. Of the first 50 resonance modes that occur, ranging from 3 to 220kHz, modes classified as longitudinal bending were most sensitive to creep damage while transverse bending modes were found to be largely unaffected. Measure to model comparisons of ΔfR show that the deformation experienced by the specimen during creep, specifically uniform elongation of the gauge section, is responsible for a majority of the measured ΔfR until at least 6.1% creep strain. After 8.8% strain considerable surface cracking along the gauge section of the dog-bone was observed, for which FE models indicate low-frequency longitudinal bending modes are significantly affected. Key differences between historical implementations of RUS for NDE and the FE model-based framework developed herein are discussed, with attention to general implementation of a FE model-based framework for NDE of damage.

  19. Radiological evaluation by magnetic resonance of the 'new anatomy' of transsexual patients undergoing male to female sex reassignment surgery.

    PubMed

    Brunocilla, E; Soli, M; Franceschelli, A; Schiavina, R; Borghesi, M; Gentile, G; Pultrone, C V; Martorana, G; Orrei, M G; Colombo, F

    2012-09-01

    Magnetic resonance (MR) is the best way to assess the new anatomy of the pelvis after male to female (MtF) sex reassignment surgery. The aim of the study was to evaluate the radiological appearance of the small pelvis after MtF surgery and to compare it with the normal women's anatomy. Fifteen patients who underwent MtF surgery were subjected to pelvic MR at least 6 months after surgery. The anthropometric parameters of the small pelvis were measured and compared with those of ten healthy women (control group). Our personal technique (creation of the mons Veneris under the pubic skin) was performed in all patients. In patients who underwent MtF surgery, the mean neovaginal depth was slightly superior than in women (P=0.009). The length of the inferior pelvic aperture and of the inlet of pelvis was higher in the control group (P<0.005). The inclination between the axis of the neovagina and the inferior pelvis aperture, the thickness of the mons Veneris and the thickness of the rectovaginal septum were comparable between the two study groups. MR consents a detailed assessment of the new pelvic anatomy after MtF surgery. The anthropometric parameters measured in our patients were comparable with those of women.

  20. On the evaluation of vorticity using cardiovascular magnetic resonance velocity measurements.

    PubMed

    Garcia, J; Larose, E; Pibarot, P; Kadem, L

    2013-12-01

    Vorticity and vortical structures play a fundamental role affecting the evaluation of energetic aspects (mainly left ventricle work) of cardiovascular function. Vorticity can be derived from cardiovascular magnetic resonance (CMR) imaging velocity measurements. However, several numerical schemes can be used to evaluate the vorticity field. The main objective of this work is to assess different numerical schemes used to evaluate the vorticity field derived from CMR velocity measurements. We compared the vorticity field obtained using direct differentiation schemes (eight-point circulation and Chapra) and derivate differentiation schemes (Richardson 4* and compact Richardson 4*) from a theoretical velocity field and in vivo CMR velocity measurements. In all cases, the effect of artificial spatial resolution up-sampling and signal-to-noise ratio (SNR) on vorticity computation was evaluated. Theoretical and in vivo results showed that the eight-point circulation method underestimated vorticity. Up-sampling evaluation showed that the artificial improvement of spatial resolution had no effect on mean absolute vorticity estimation but it affected SNR for all methods. The Richardson 4* method and its compact version were the most accurate and stable methods for vorticity magnitude evaluation. Vorticity field determination using the eight-point circulation method, the most common method used in CMR, has reduced accuracy compared to other vorticity schemes. Richardson 4* and its compact version showed stable SNR using both theoretical and in vivo data.

  1. The role of magnetic resonance imaging in the evaluation of transfusional iron overload in myelodysplastic syndromes

    PubMed Central

    Petrou, Emmanouil; Mavrogeni, Sophie; Karali, Vasiliki; Kolovou, Genovefa; Kyrtsonis, Marie-Christine; Sfikakis, Petros P.; Panayiotidis, Panayiotis

    2015-01-01

    Myelodysplastic syndromes represent a group of heterogeneous hematopoietic neoplasms derived from an abnormal multipotent progenitor cell, characterized by a hyperproliferative bone marrow, dysplasia of the cellular hemopoietic elements and ineffective erythropoiesis. Anemia is a common finding in myelodysplastic syndrome patients, and blood transfusions are the only therapeutic option in approximately 40% of cases. The most serious side effect of regular blood transfusion is iron overload. Currently, cardiovascular magnetic resonance using T2 is routinely used to identify patients with myocardial iron overload and to guide chelation therapy, tailored to prevent iron toxicity in the heart. This is a major validated non-invasive measure of myocardial iron overloading and is superior to surrogates such as serum ferritin, liver iron, ventricular ejection fraction and tissue Doppler parameters. The indication for iron chelation therapy in myelodysplastic syndrome patients is currently controversial. However, cardiovascular magnetic resonance may offer an excellent non-invasive, diagnostic tool for iron overload assessment in myelodysplastic syndromes. Further studies are needed to establish the precise indications of chelation therapy and the clinical implications of this treatment on survival in myelodysplastic syndromes. PMID:26190429

  2. Numerical evaluation of aperture coupling in resonant cavities and frequency perturbation analysis

    NASA Astrophysics Data System (ADS)

    Dash, R.; Nayak, B.; Sharma, A.; Mittal, K. C.

    2014-01-01

    This paper presents a general formulation for numerical evaluation of the coupling between two identical resonant cavities by a small elliptical aperture in a plane common wall of arbitrary thickness. It is organized into two parts. In the first one we discuss the aperture coupling that is expressed in terms of electric and magnetic dipole moments and polarizabilities using Carlson symmetric elliptical integrals. Carlson integrals have been numerically evaluated and under zero thickness approximation, the results match with the complete elliptical integrals of first and second kind. It is found that with zero wall thickness, the results obtained are the same as those of Bethe and Collin for an elliptical and circular aperture of zero thickness. In the second part, Slater's perturbation method is applied to find the frequency changes due to apertures of finite thickness on the cavity wall.

  3. Evaluation Of Automated Low-Field Nuclear Magnetic Resonance (NMR) Relaxometry For Analysis Of Silicone Polymers

    SciTech Connect

    M. H. Wilson

    2009-10-02

    Screening studies and Design of Experiments (DoE) were performed to evaluate measurement variation of a new, non-destructive Nuclear Magnetic Resonance (NMR) test system designed to assess age-induced degradation of Outer Pressure Pads (OPP). The test method and results from 54,275 measurements are described. A reduction in measurement error was obtained after metal support struts were replaced with plastic support struts adjacent to the front position of the test chamber. However, remaining interference and a lack of detecting any age-related degradation prevent the use of the NMR system as a non-destructive surveillance test for OPPs. A cursory evaluation of the system with cellular silicone samples obtained more uniform results with increased error as measurements approached the sample’s edge.

  4. Evaluation of Possible Nuclear Magnetic Resonance Diagnostic Techniques for Tokamak Experiments

    SciTech Connect

    S.J. Zweben; T.W. Kornack; D. Majeski; G. Schilling; C.H. Skinner; R. Wilson

    2002-08-05

    Potential applications of nuclear magnetic resonance (NMR) diagnostic techniques to tokamak experiments are evaluated. NMR frequencies for hydrogen isotopes and low-Z nuclei in such experiments are in the frequency range approximately equal to 20-200 MHz, so existing RF [radio-frequency] antennas could be used to rotate the spin polarization and to make the NMR measurements. Our tentative conclusion is that such measurements are possible if highly spin polarized H or (superscript)3He gas sources (which exist) are used to fuel these plasmas. In addition, NMR measurements of the surface layers of the first wall (without plasma) may also be possible, e.g., to evaluate the inventory of tritium inside the vessel.

  5. Comparison of magnetic resonance imaging and ultrasonography in the evaluation of abdominal aortic aneurysms.

    PubMed

    Amparo, E G; Hoddick, W K; Hricak, H; Sollitto, R; Justich, E; Filly, R A; Higgins, C B

    1985-02-01

    Magnetic resonance imaging (MRI) was used to evaluate abdominal aortic aneurysms in 27 patients. The findings were compared retrospectively with CT, ultrasound (US), and angiography in 17 cases and prospectively with US in 10 cases. MRI identified the renal arteries in all cases, demonstrated involvement at or above the origin of the renal arteries in eight patients, and showed extension of the aneurysm into the iliac arteries in 12 cases. The outer dimension of the aneurysm, the diameter of the residual lumen, and the length of the aneurysm were measured easily from the MR images. The measurements of transverse dimension of the abdominal aortic aneurysm were similar for MRI, CT, and US. MRI more accurately defined extension above the renal arteries and below the aortic bifurcation. It is concluded that MRI provides the necessary information for the surveillance and preoperative evaluation of abdominal aortic aneurysms.

  6. Sperm motility parameters to evaluate the seminal quality of Boa constrictor occidentalis, a threatened snake species.

    PubMed

    Tourmente, M; Cardozo, G A; Guidobaldi, H A; Giojalas, L C; Bertona, M; Chiaraviglio, M

    2007-02-01

    Semen quality analysis constitutes a powerful tool to evaluate the fertility potential of males in threatened species. The Argentine boa constrictor or lampalagua (Boa constrictor occidentalis) is a threatened snake species and has been included in Appendix I of CITES. The objective of this work is to characterize the sperm of B. c. occidentalis on the bases of dynamic parameters to improve this species conservation. Dynamic parameters were measured in sperm samples using videomicroscopy and image analysis software. The sperm population showed a high degree of heterogeneity in velocity parameter values and 95% of the cells showed a linear pattern of movement. Studies in other species indicate that the number of motile spermatozoa and their movement speed is directly correlated with fertilization success. This work will help to establish basic parameter values for the evaluation of the reproductive potential of populations of B. c. occidentalis and to resolve questions referred to its reproductive strategies.

  7. Theoretical-Experimental Method for Evaluating the Elastic and Damping Characteristics of Soft Materials Based on Studying the Resonance Flexural Vibrations of Test Specimens

    NASA Astrophysics Data System (ADS)

    Paimushin, V. N.; Firsov, V. A.; Gyunal, I.; Shishkin, V. M.

    2016-11-01

    A hardware and software system for studying the damping and elastic properties of soft materials in a low-frequency range of deformation up to 100 Hz, which most fully corresponds to the range of dynamic actions in actual service conditions of structures, is proposed. A novel identification method for evaluating the elastic and damping properties of soft materials in shear is developed. It employs the frequency and amplitude characteristics of the resonance flexural vibrations of three-layer test specimens with a soft inner layer. Identification of the elastic shear properties is based on a comparison of calculated and experimental frequencies of resonance vibrations of test specimens. To evaluate the shear damping properties of soft materials, the condition of minimum of an objective function containing experimental and calculated amplitudes of vibrations of the free end of a test specimen is used. The possibility of evaluating the properties mentioned from the experimental and calculated internal damping parameters of test specimens, which significantly reduces the laboriousness of the problem considered, is shown. Numerical calculations are carried out for identifying the elastic and damping characteristics of a technical rubber in shear based on an analysis of resonance flexural vibrations of seven test specimens with outer layers made of a D16AT aluminum alloy.

  8. Magnetic resonance angiography for the evaluation of vascular injury in knee dislocations.

    PubMed

    Tocci, Stephen L; Heard, Wendell M R; Fadale, Paul D; Brody, Jeffrey M; Born, Christopher

    2010-12-01

    Knee dislocations can cause extensive soft tissue disruption including vascular insufficiency to the leg secondary to popliteal artery injury. Physical exam may miss vascular injury and possible late occlusion, but there is controversy regarding use of angiography to evaluate patients after dislocation. Magnetic resonance angiography (MRA) has been shown to be equally effective as angiography in evaluating vascular injury and to have fewer complications than angiography. Patients with knee dislocations routinely receive magnetic resonance imaging (MRI) to assess ligament integrity. The purpose of our study was to determine whether it may be prudent and convenient to obtain an MR angiogram at the same time as an MRI scan, with less morbidity and discomfort than with conventional angiography. Sixteen patients with frank and occult knee dislocations were prospectively evaluated over 2 years. After reduction, a physical exam was performed including ankle brachial index (ABI). With ABI < 0.90, emergent vascular surgery consult and angiogram was performed. Patients with ABI > 0.90 were observed for 3 days with serial physical exams, and MRI/MRA was performed as soon as possible. Sixteen dislocations were identified. Two of 16 (12.5%) had abnormal ABIs and received an angiogram and subsequent revascularization. Two had normal exams, but refused MRA. Twelve had normal exams and received MRI/MRA showing a normal popliteal artery with no adverse events. ABI had 100% sensitivity for vascular injury; however, there remains concern among treating surgeons about missing an occult injury such as an intimal tear. Because MRA has been shown to be as accurate and useful as angiography, we may be able to evaluate ligamentous and vascular injury simultaneously with less morbidity than that with conventional angiography.

  9. Evaluation of cathepsin B activity for degrading collagen IV using a surface plasmon resonance method and circular dichroism spectroscopy.

    PubMed

    Shoji, Atsushi; Kabeya, Mitsutaka; Ishida, Yuuki; Yanagida, Akio; Shibusawa, Yoichi; Sugawara, Masao

    2014-07-01

    Evaluation of cathepsin B activities for degrading collagen IV and heat-denatured collagen IV (gelatin) were performed by surface plasmon resonance (SPR) and circular dichroism (CD) measurements. The optimal pH of cathepsin B activity for degrading each substrate was around 4.0. The ΔRU(15 min), which is a decrease in the SPR signal at 15 min after injection of cathepsin B, was smaller for collagen IV than for heat-denatured collagen IV owing to the presence of triple-helical conformation. An unstable nature of the triple-helical conformation of collagen IV at pH 4.0 was shown by the CD study. Degrading collagen IV by cathepsin B was facilitated owing to a local unwinding of the triple-helical conformation caused by proteolytic cleavage of the non-helical region. The concentration dependence of the initial velocity for degrading collagen IV by cathepsin B at pH 4.0 was biphasic, showing that cathepsin B at low concentration exhibits exopeptidase activity, while the enzyme at high concentration exhibits endopeptidase activity. The kinetic parameters for the exopeptidase activity of cathepsin B toward collagen IV and heat-treated collagen IV were evaluated and discussed in terms of the protease mechanism.

  10. Electrical and ionic conductivity effects on magic-angle spinning nuclear magnetic resonance parameters of CuI.

    PubMed

    Yesinowski, James P; Ladouceur, Harold D; Purdy, Andrew P; Miller, Joel B

    2010-12-21

    We investigate experimentally and theoretically the effects of two different types of conductivity, electrical and ionic, upon magic-angle spinning NMR spectra. The experimental demonstration of these effects involves (63)Cu, (65)Cu, and (127)I variable temperature MAS-NMR experiments on samples of γ-CuI, a Cu(+)-ion conductor at elevated temperatures as well as a wide bandgap semiconductor. We extend previous observations that the chemical shifts depend very strongly upon the square of the spinning-speed as well as the particular sample studied and the magnetic field strength. By using the (207)Pb resonance of lead nitrate mixed with the γ-CuI as an internal chemical shift thermometer we show that frictional heating effects of the rotor do not account for the observations. Instead, we find that spinning bulk CuI, a p-type semiconductor due to Cu(+) vacancies in nonstoichiometric samples, in a magnetic field generates induced AC electric currents from the Lorentz force that can resistively heat the sample by over 200 °C. These induced currents oscillate along the rotor spinning axis at the spinning speed. Their associated heating effects are disrupted in samples containing inert filler material, indicating the existence of macroscopic current pathways between micron-sized crystallites. Accurate measurements of the temperature-dependence of the (63)Cu and (127)I chemical shifts in such diluted samples reveal that they are of similar magnitude (ca. 0.27 ppm/K) but opposite sign (being negative for (63)Cu), and appear to depend slightly upon the particular sample. This relationship is identical to the corresponding slopes of the chemical shifts versus square of the spinning speed, again consistent with sample heating as the source of the observed large shift changes. Higher drive-gas pressures are required to spin samples that have higher effective electrical conductivities, indicating the presence of a braking effect arising from the induced currents produced by

  11. Incidence and Evaluation of Incidental Abnormal Bone Marrow Signal on Magnetic Resonance Imaging

    PubMed Central

    Shah, Gunjan L.; Rosenberg, Aaron S.; Jarboe, Jamie; Klein, Andreas; Cossor, Furha

    2014-01-01

    Purpose. The increased use of magnetic resonance imaging (MRI) has resulted in reports of incidental abnormal bone marrow (BM) signal. Our goal was to determine the evaluation of an incidental abnormal BM signal on MRI and the prevalence of a subsequent oncologic diagnosis. Methods. We conducted a retrospective cohort study of patients over age 18 undergoing MRI between May 2005 and October 2010 at Tufts Medical Center (TMC) with follow-up through November 2013. The electronic medical record was queried to determine imaging site, reason for scan, evaluation following radiology report, and final diagnosis. Results. 49,678 MRIs were done with 110 patients meeting inclusion criteria. Twenty two percent underwent some evaluation, most commonly a complete blood count, serum protein electrophoresis, or bone scan. With median follow-up of 41 months, 6% of patients were diagnosed with malignancies including multiple myeloma, non-Hodgkins lymphoma, metastatic non-small cell lung cancer, and metastatic adenocarcinoma. One patient who had not undergone evaluation developed breast cancer 24 months after the MRI. Conclusions. Incidentally noted abnormal or heterogeneous bone marrow signal on MRI was not inconsequential and should prompt further evaluation. PMID:25374938

  12. Evaluation of multiatlas label fusion for in vivo magnetic resonance imaging orbital segmentation

    PubMed Central

    Panda, Swetasudha; Asman, Andrew J.; Khare, Shweta P.; Thompson, Lindsey; Mawn, Louise A.; Smith, Seth A.; Landman, Bennett A.

    2014-01-01

    Abstract. Multiatlas methods have been successful for brain segmentation, but their application to smaller anatomies remains relatively unexplored. We evaluate seven statistical and voting-based label fusion algorithms (and six additional variants) to segment the optic nerves, eye globes, and chiasm. For nonlocal simultaneous truth and performance level estimation (STAPLE), we evaluate different intensity similarity measures (including mean square difference, locally normalized cross-correlation, and a hybrid approach). Each algorithm is evaluated in terms of the Dice overlap and symmetric surface distance metrics. Finally, we evaluate refinement of label fusion results using a learning-based correction method for consistent bias correction and Markov random field regularization. The multiatlas labeling pipelines were evaluated on a cohort of 35 subjects including both healthy controls and patients. Across all three structures, nonlocal spatial STAPLE (NLSS) with a mixed weighting type provided the most consistent results; for the optic nerve NLSS resulted in a median Dice similarity coefficient of 0.81, mean surface distance of 0.41 mm, and Hausdorff distance 2.18 mm for the optic nerves. Joint label fusion resulted in slightly superior median performance for the optic nerves (0.82, 0.39 mm, and 2.15 mm), but slightly worse on the globes. The fully automated multiatlas labeling approach provides robust segmentations of orbital structures on magnetic resonance imaging even in patients for whom significant atrophy (optic nerve head drusen) or inflammation (multiple sclerosis) is present. PMID:25558466

  13. An automated procedure for material parameter evaluation for viscoplastic constitutive models

    NASA Technical Reports Server (NTRS)

    Imbrie, P. K.; James, G. H.; Hill, P. S.; Allen, D. H.; Haisler, W. E.

    1988-01-01

    An automated procedure is presented for evaluating the material parameters in Walker's exponential viscoplastic constitutive model for metals at elevated temperature. Both physical and numerical approximations are utilized to compute the constants for Inconel 718 at 1100 F. When intermediate results are carefully scrutinized and engineering judgement applied, parameters may be computed which yield stress output histories that are in agreement with experimental results. A qualitative assessment of the theta-plot method for predicting the limiting value of stress is also presented. The procedure may also be used as a basis to develop evaluation schemes for other viscoplastic constitutive theories of this type.

  14. Nonlinear resonance

    NASA Astrophysics Data System (ADS)

    Kevorkian, J.; Pernarowski, Mark; Bosley, David L.

    1990-04-01

    The subjects discussed are: transient and sustained resonance for systems with very slowly varying parameters; free electron lasers with very slow wiggler taper; and bursting oscillations in biological systems. Plans are discussed for: FEL applications; transient and sustained resonance; and bursting oscillations.

  15. Study of the selection of indicator parameters in marine water quality evaluation and the evaluation methodology

    NASA Astrophysics Data System (ADS)

    Zhang, Ying; Pan, Delu; Wang, Difeng; Fu, Dongyang

    2014-10-01

    In order to obtain the indicator types which must be introduced in marine water quality evaluation as well as the suitable evaluation methodology, GB3097-1997 National Marine Water Quality Standards is, in the first place, analyzed to establish a hypothetical sample which is consisting of 2000 stances, each stance containing the information of 21 indicators. And then a stepwise discriminant method is utilized to filter the 21 indicators in accordance with their water quality classification discriminant abilities. And finally, 6 indicators with significant discriminant ability, biochemical oxygen demand(BOD5), oil type(Oil), total phosphorus(P), cadmium(Cd), cyanide(HH) and chemical oxygen demand(COD), are selected and the water quality evaluation chart of the corresponding six indicators is also established. Theoretically, the water quality indicator types and the suitable evaluation methodology, which must be introduced when the water quality evaluation is done in all the waters under the jurisdiction of China, are discussed in this paper, providing theoretical basis for the subsequent marine water quality evaluation based on field observation.

  16. CONTROL OF LASER RADIATION PARAMETERS: Method for calculating a negative-dispersion resonator-type multilayer mirror

    NASA Astrophysics Data System (ADS)

    Kholokhonova, Polina A.; Erg, G. V.

    2005-11-01

    A method is proposed for the calculation of negative-dispersion mirrors with resonator cavities. The mirror optimisation algorithm combines the capabilities of the gradient method and the random search method. A multilayer mirror structure with a reflectivity R>99.9% and a group delay dispersion of -60±10 fs2 in the 930-1070 nm wavelength range was calculated. The sensitivity of the obtained structure to random variations of layer thicknesses was analysed.

  17. Detection and Classification of Buried UXO and Determination of Seafloor Parameters in Littoral Environments using Resonance Scattering Sonar

    DTIC Science & Technology

    2010-04-02

    Environmental Technology Technical Symposium and Workshop, Washington, D.C. Cobb, W. (2006), Acoustic identification of filler materials in unexploded...Underwater UXO Using Resonance Scattered Sonar, Partners in Environmental Technology Technical Symposium and Workshop, Washington, D.C., Dec. 1-3...Nelson, H., Yoder, T, Kraus, L. and Carin L., 2009, Broadband, Multi-Aspect Scattering from UXO, Partners in Environmental Technology Technical

  18. Evaluation of thermal effects on the beam quality of disk laser with unstable resonator

    NASA Astrophysics Data System (ADS)

    Shayganmanesh, Mahdi; Beirami, Reza

    2017-01-01

    In this paper thermal effects of the disk active medium and associated effects on the beam quality of laser are investigated. Using Collins integral and iterative method, transverse mode of an unstable resonator including a Yb:YAG active medium in disk geometry is calculated. After that the beam quality of the laser is calculated based on the generalized beam characterization method. Thermal lensing of the disk is calculated based on the OPD (Optical Path Difference) concept. Five factors influencing the OPD including temperature gradient, disk thermal expansion, photo-elastic effect, electronic lens and disk deformation are considered in our calculations. The calculations show that the effect of disk deformation factor on the quality of laser beam in the resonator is strong. However the total effect of all the thermal factors on the internal beam quality is fewer. Also it is shown that thermal effects degrade the output power, beam profile and beam quality of the output laser beam severely. As well the magnitude of each of affecting factors is evaluated distinctly.

  19. Classification of the micro and nanoparticles and biological agents by neural network analysis of the parameters of optical resonance of whispering gallery mode in dielectric microspheres

    NASA Astrophysics Data System (ADS)

    Saetchnikov, Vladimir A.; Tcherniavskaia, Elina A.; Schweiger, Gustav; Ostendorf, Andreas

    2011-07-01

    A novel technique for the label-free analysis of micro and nanoparticles including biomolecules using optical micro cavity resonance of whispering-gallery-type modes is being developed. Various schemes of the method using both standard and specially produced microspheres have been investigated to make further development for microbial application. It was demonstrated that optical resonance under optimal geometry could be detected under the laser power of less 1 microwatt. The sensitivity of developed schemes has been tested by monitoring the spectral shift of the whispering gallery modes. Water solutions of ethanol, ascorbic acid, blood phantoms including albumin and HCl, glucose, biotin, biomarker like C reactive protein so as bacteria and virus phantoms (gels of silica micro and nanoparticles) have been used. Structure of resonance spectra of the solutions was a specific subject of investigation. Probabilistic neural network classifier for biological agents and micro/nano particles classification has been developed. Several parameters of resonance spectra as spectral shift, broadening, diffuseness and others have been used as input parameters to develop a network classifier for micro and nanoparticles and biological agents in solution. Classification probability of approximately 98% for probes under investigation have been achieved. Developed approach have been demonstrated to be a promising technology platform for sensitive, lab-on-chip type sensor which can be used for development of diagnostic tools for different biological molecules, e.g. proteins, oligonucleotides, oligosaccharides, lipids, small molecules, viral particles, cells as well as in different experimental contexts e.g. proteomics, genomics, drug discovery, and membrane studies.

  20. Quantitative evaluation of proteins with bicinchoninic acid (BCA): resonance Raman and surface-enhanced resonance Raman scattering-based methods.

    PubMed

    Chen, Lei; Yu, Zhi; Lee, Youngju; Wang, Xu; Zhao, Bing; Jung, Young Mee

    2012-12-21

    A rapid and highly sensitive bicinchoninic acid (BCA) reagent-based protein quantitation tool was developed using competitive resonance Raman (RR) and surface-enhanced resonance Raman scattering (SERRS) methods. A chelation reaction between BCA and Cu(+), which is reduced by protein in an alkaline environment, is exploited to create a BCA-Cu(+) complex that has strong RR and SERRS activities. Using these methods, protein concentrations in solutions can be quantitatively measured at concentrations as low as 50 μg mL(-1) and 10 pg mL(-1). There are many advantages of using RR and SERRS-based assays. These assays exhibit a much wider linear concentration range and provide an additional one (RR method) to four (SERRS method) orders of magnitude increase in detection limits relative to UV-based methods. Protein-to-protein variation is determined using a reference to a standard curve at concentrations of BSA that exhibits excellent recoveries. These novel methods are extremely accurate in detecting total protein concentrations in solution. This improvement in protein detection sensitivity could yield advances in the biological sciences and medical diagnostic field and extend the applications of reagent-based protein assay techniques.

  1. SENSITIVE PARAMETER EVALUATION FOR A VADOSE ZONE FATE AND TRANSPORT MODEL

    EPA Science Inventory

    This report presents information pertaining to quantitative evaluation of the potential impact of selected parameters on output of vadose zone transport and fate models used to describe the behavior of hazardous chemicals in soil. The Vadose 2one Interactive Processes (VIP) model...

  2. Important Physiological Parameters and Physical Activity Data for Evaluating Exposure Modeling Performance: a Synthesis

    EPA Science Inventory

    The purpose of this report is to develop a database of physiological parameters needed for understanding and evaluating performance of the APEX and SHEDS exposure/intake dose rate model used by the Environmental Protection Agency (EPA) as part of its regulatory activities. The A...

  3. Mathematical modeling and evaluation of radionuclide transport parameters from the ANL Laboratory Analog Program

    SciTech Connect

    Chen, B.C.J.; Hull, J.R.; Seitz, M.G.; Sha, W.T.; Shah, V.L.; Soo, S.L.

    1984-07-01

    Computer model simulation is required to evaluate the performance of proposed or future high-level radioactive waste geological repositories. However, the accuracy of a model in predicting the real situation depends on how well the values of the transport properties are prescribed as input parameters. Knowledge of transport parameters is therefore essential. We have modeled ANL's Experiment Analog Program which was designed to simulate long-term radwaste migration process by groundwater flowing through a high-level radioactive waste repository. Using this model and experimental measurements, we have evaluated neptunium (actinide) deposition velocity and analyzed the complex phenomena of simultaneous deposition, erosion, and reentrainment of bentonite when groundwater is flowing through a narrow crack in a basalt rock. The present modeling demonstrates that we can obtain the values of transport parameters, as added information without any additional cost, from the available measurements of laboratory analog experiments. 8 figures, 3 tables.

  4. Multi-frequency weak signal detection based on wavelet transform and parameter compensation band-pass multi-stable stochastic resonance

    NASA Astrophysics Data System (ADS)

    Han, Dongying; li, Pei; An, Shujun; Shi, Peiming

    2016-03-01

    In actual fault diagnosis, useful information is often submerged in heavy noise, and the feature information is difficult to extract. A novel weak signal detection method aimed at the problem of detecting multi-frequency signals buried under heavy background noise is proposed based on wavelet transform and parameter compensation band-pass multi-stable stochastic resonance (SR). First, the noisy signal is processed by parameter compensation, with the noise and system parameters expanded 10 times to counteract the effect of the damping term. The processed signal is decomposed into multiple signals of different scale frequencies by wavelet transform. Following this, we adjust the size of the scaled signals' amplitudes and reconstruct the signals; the weak signal frequency components are then enhanced by multi-stable stochastic resonance. The enhanced components of the signal are processed through a band-pass filter, leaving the enhanced sections of the signal. The processed signal is analyzed by FFT to achieve detection of the multi-frequency weak signals. The simulation and experimental results show that the proposed method can enhance the signal amplitude, can effectively detect multi-frequency weak signals buried under heavy noise and is valuable and usable for bearing fault signal analysis.

  5. Usefulness of contrast-enhanced magnetic resonance imaging for evaluating solitary pulmonary nodules

    PubMed Central

    2008-01-01

    Abstract Evaluation of solitary pulmonary nodules (SPNs) poses a challenge to radiologists. Chest computed tomography (CT) is considered the standard technique for assessing morphologic findings and intrathoracic spread of an SPN. Although the clinical role of magnetic resonance imaging (MRI) for SPNs remains limited, considerable experience has been gained with MRI of thoracic diseases. Dynamic MRI and dynamic CT are useful for differentiating between malignant and benign SPNs (especially tuberculomas and hamartomas). Furthermore, dynamic MRI is useful for assessing tumor vascularity, interstitium, and vascular endothelial growth factor expression, and for predicting survival outcome among patients with peripheral pulmonary carcinoma. These advantages make dynamic MRI a promising method and a potential biomarker for characterizing tumor response to anti-angiogenic treatment as well as for predicting survival outcomes after treatment. PMID:18331971

  6. Comparison of magnetic resonance imaging and radionuclide imaging in the evaluation of renal transplant failure

    SciTech Connect

    Goldsmith, M.S.; Tanasescu, D.E.; Waxman, A.D.; Crues, J.V. III

    1988-04-01

    Magnetic resonance imaging (MRI) was compared with radionuclide scintigraphy (RNS) in 16 patients with renal transplants undergoing renal failure to determine which modality could best discriminate between rejection, acute tubular necrosis (ATN), and cyclosporin nephrotoxicity (CN). Although all rejecting transplants had reduced corticomedullary differentiation (CMD) on T1-weighted MR images, four of five cases of ATN had appearances that could not be distinguished from rejection. A normal CMD suggests nonrejection, but diminished CMD is nonspecific. Tc-99m DTPA/I-131 hippuran RNS was superior to MRI in differentiating rejection from ATN. Although ATN and CN have similar RNS patterns, this distinction can usually be made based on the clinical time course. Other potential uses of MRI in the evaluation of the renal transplants are discussed.

  7. Hepatic hemangiomas: evaluation by magnetic resonance imaging and technetium-99m red blood cell scintigraphy

    SciTech Connect

    Brown, R.K.; Gomes, A.; King, W.; Pusey, E.; Lois, J.; Goldstein, L.; Busuttil, R.W.; Hawkins, R.A.

    1987-11-01

    A study was performed to evaluate and compare the sensitivity of magnetic resonance imaging (MRI) and radionuclide blood-pool scanning in the detection of hepatic hemangiomas. All patients had known hemangiomas which were first detected on either ultrasound or computed tomography. Sixteen patients with a total of 23 lesions were investigated. Eleven patients had both MRI and blood-pool scans performed. In the group studied by both modalities, 18 lesions were detected ranging in size from 1 to 11 cm. All lesions were detected by both techniques. However, two of the 18 lesions had an atypical appearance on MRI. Our experience to date indicates that the anatomic location and specific diagnosis of hemangiomas can be made with a high degree of certainty when both MRI and blood-pool scanning techniques are utilized.

  8. Cavernosal nerve functionality evaluation after magnetic resonance imaging-guided transurethral ultrasound treatment of the prostate

    PubMed Central

    Sammet, Steffen; Partanen, Ari; Yousuf, Ambereen; Sammet, Christina L; Ward, Emily V; Wardrip, Craig; Niekrasz, Marek; Antic, Tatjana; Razmaria, Aria; Farahani, Keyvan; Sokka, Shunmugavelu; Karczmar, Gregory; Oto, Aytekin

    2015-01-01

    AIM: To evaluate the feasibility of using therapeutic ultrasound as an alternative treatment option for organ-confined prostate cancer. METHODS: In this study, a trans-urethral therapeutic ultrasound applicator in combination with 3T magnetic resonance imaging (MRI) guidance was used for real-time multi-planar MRI-based temperature monitoring and temperature feedback control of prostatic tissue thermal ablation in vivo. We evaluated the feasibility and safety of MRI-guided trans-urethral ultrasound to effectively and accurately ablate prostate tissue while minimizing the damage to surrounding tissues in eight canine prostates. MRI was used to plan sonications, monitor temperature changes during therapy, and to evaluate treatment outcome. Real-time temperature and thermal dose maps were calculated using the proton resonance frequency shift technique and were displayed as two-dimensional color-coded overlays on top of the anatomical images. After ultrasound treatment, an evaluation of the integrity of cavernosal nerves was performed during prostatectomy with a nerve stimulator that measured tumescence response quantitatively and indicated intact cavernous nerve functionality. Planned sonication volumes were visually correlated to MRI ablation volumes and corresponding histo-pathological sections after prostatectomy. RESULTS: A total of 16 sonications were performed in 8 canines. MR images acquired before ultrasound treatment were used to localize the prostate and to prescribe sonication targets in all canines. Temperature elevations corresponded within 1 degree of the targeted sonication angle, as well as with the width and length of the active transducer elements. The ultrasound treatment procedures were automatically interrupted when the temperature in the target zone reached 56 °C. In all canines erectile responses were evaluated with a cavernous nerve stimulator post-treatment and showed a tumescence response after stimulation with an electric current. These

  9. Evaluation of an instrumented walkway for measurement of the kinematic parameters of gait.

    PubMed

    Cutlip, R G; Mancinelli, C; Huber, F; DiPasquale, J

    2000-10-01

    The purpose of this study was to compare kinematic gait parameters measured with an instrumented walkway system (GAITRite(R)) and a video-based system (peak performance motus 3.1(R)). Subjects walked across a GAITRite mat with embedded pressure sensors. Reflective markers were attached to subjects' shoes and video capture was simultaneously performed during each trial. Video data were then digitized manually using peak software. Correlation coefficients for all parameters measured with both systems were high (>/=0.94). Significant differences between systems were found with analysis of variance (ANOVA) for two parameters, step length and stride velocity (P=0.003, 0.0002). The results of this study indicate that the instrumented walkway gave comparable results for temporal parameters but further investigation is needed to evaluate the fidelity of its spatial performance.

  10. Evaluation of a new parallel numerical parameter optimization algorithm for a dynamical system

    NASA Astrophysics Data System (ADS)

    Duran, Ahmet; Tuncel, Mehmet

    2016-10-01

    It is important to have a scalable parallel numerical parameter optimization algorithm for a dynamical system used in financial applications where time limitation is crucial. We use Message Passing Interface parallel programming and present such a new parallel algorithm for parameter estimation. For example, we apply the algorithm to the asset flow differential equations that have been developed and analyzed since 1989 (see [3-6] and references contained therein). We achieved speed-up for some time series to run up to 512 cores (see [10]). Unlike [10], we consider more extensive financial market situations, for example, in presence of low volatility, high volatility and stock market price at a discount/premium to its net asset value with varying magnitude, in this work. Moreover, we evaluated the convergence of the model parameter vector, the nonlinear least squares error and maximum improvement factor to quantify the success of the optimization process depending on the number of initial parameter vectors.

  11. Relating objective measurements to expert evaluation of voice quality in Western classical singing: critical perceptual parameters.

    PubMed

    Ekholm, E; Papagiannis, G C; Chagnon, F P

    1998-06-01

    Communication between voice pedagogues and voice scientists is often impeded by reliance on colorful and sometimes seemingly contradictory descriptions of vocal production and voice quality. A recent study identified perceptual criteria which are generally used by voice experts for the assessment of voice quality in classical singing. In the present study, performances by singers of various voice types and levels of accomplishment were rated by panels of expert voice teachers according to four perceptual criteria: "resonance/ring," "color/warmth," "clarity/focus," and "appropriate vibrato." Subjective ratings were related to objective measurements taken from acoustic analysis of the voice signal. Possible acoustic correlates of critical perceptual parameters influencing judgments of voice quality were thus identified. Results could help bridge the terminology gap between vocal artists and scientists, and help to promote understanding of the way in which acoustic stimuli influence perception of voice quality.

  12. Impact of gamma analysis parameters on dose evaluation using Gafchromic EBT2 films

    NASA Astrophysics Data System (ADS)

    Lee, Seu-Ran; Park, Ji-Yeon; Suh, Tae-Suk; Park, Hae-Jin; Lee, Jeong-Woo; Jung, Won-Gyun

    2012-10-01

    To recommend optimal gamma analysis parameters (grid size and search range) for detecting dose errors, we evaluated the impact of gamma models and parameters on dose verification in volumetric modulated fields. Delivered doses were verified under open, 45° wedged, and volumetric modulated fields for prostate, anal, head and neck, and brain cancer by using Gafchromic EBT2 films for gamma evaluation. Two gamma models (a conventional method and a modified method to compensate for unintended dose errors caused by misalignments between reference and evaluated matrixes) were employed. The variation in the detected dose errors was evaluated in each gamma model for different grid sizes (0.5, 1, and 2 mm) and search ranges (1, 2, and 4 mm) applied to determine distant-to-agreement. The dose discrepancy of each evaluation was qualitatively and quantitatively evaluated using a pass ratio in analysis software developed in-house. The modified gamma model with a small search range and grid size showed a higher pass ratio than the conventional model in volumetric modulated arc therapy. The pass ratio for 2 mm grid size decreased by over 40% as compared to that for 1 mm grid size. The pass ratio decreased by more than 30% as the search range was increased from 1 mm to 4 mm. Therefore, 1 mm grid size and 1 mm search range may be appropriate to evaluate dose errors in modulated fields after using the modified gamma model.

  13. Evaluating Human Breast Ductal Carcinomas with High-Resolution Magic-Angle Spinning Proton Magnetic Resonance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Cheng, Leo Ling; Chang, I.-Wen; Smith, Barbara L.; Gonzalez, R. Gilberto

    1998-11-01

    We report the results of a study of human breast ductal carcinomas, conducted by using high resolution magic angle spinning proton magnetic resonance spectroscopy (HRMAS 1HMRS). This recently developed spectroscopic technique can measure tissue metabolism from intact pathological specimens and identify tissue biochemical changes, which closely correspond to tumorin vivostate. This procedure objectively indicates diagnostic parameters, independent of the skill and experience of the investigator, and has the potential to reduce the sampling errors inherently associated with procedures of conventional histopathology. In this study, we measured 19 cases of female ductal carcinomas. Our results demonstrate that: (1) highly resolved spectra of intact specimens of human breast ductal carcinomas can be obtained; (2) carcinoma-free tissues and carcinomas are distinguishable by alterations in the intensities and the spin-spin relaxation time T2 of cellular metabolites; and (3) tumor metabolic markers, such as phosphocholine, lactate, and lipids, may correlate with the histopathological grade determined from evaluation of the adjacent specimen. Our results suggest that biochemical markers thus measured may function as a valuable adjunct to histopathology to improve the accuracy of and reduce the time frame required for the diagnosis of human breast cancer.

  14. A two-temperature model for evaluation of thermoelastic damping in the vibration of a nanoscale resonators

    NASA Astrophysics Data System (ADS)

    Abbas, Ibrahim A.

    2016-11-01

    In this work, the thermoelastic damping of a nano-scale resonator is analyzed by the generalized thermoelasticity theory based on two-temperature model (2TLS). The effect of two-temperature parameter and relaxation time in nano-scale resonator are investigated for beams under clamped conditions. Analytical expressions for deflection, temperature change, frequency shifts, and thermoelastic damping in the beam have been derived. The theories of coupled termoelasticity and generalized thermoelasticity with one relaxation time can extracted as limited and special cases of the present model. The numerical results have been presented graphically in respect of thermoelastic damping and frequency shift.

  15. Evaluation and interpretation of Thematic Mapper ratios in equations for estimating corn growth parameters

    NASA Technical Reports Server (NTRS)

    Dardner, B. R.; Blad, B. L.; Thompson, D. R.; Henderson, K. E.

    1985-01-01

    Reflectance and agronomic Thematic Mapper (TM) data were analyzed to determine possible data transformations for evaluating several plant parameters of corn. Three transformation forms were used: the ratio of two TM bands, logarithms of two-band ratios, and normalized differences of two bands. Normalized differences and logarithms of two-band ratios responsed similarly in the equations for estimating the plant growth parameters evaluated in this study. Two-term equations were required to obtain the maximum predictability of percent ground cover, canopy moisture content, and total wet phytomass. Standard error of estimate values were 15-26 percent lower for two-term estimates of these parameters than for one-term estimates. The terms log(TM4/TM2) and (TM4/TM5) produced the maximum predictability for leaf area and dry green leaf weight, respectively. The middle infrared bands TM5 and TM7 are essential for maximizing predictability for all measured plant parameters except leaf area index. The estimating models were evaluated over bare soil to discriminate between equations which are statistically similar. Qualitative interpretations of the resulting prediction equations are consistent with general agronomic and remote sensing theory.

  16. Incremental parameter evaluation from incomplete data with application to the population pharmacology of anticoagulants

    PubMed Central

    Vlad, Marcel O.; Dan Corlan, Alexandru; Morán, Federico; Oefner, Peter; Ross, John

    2008-01-01

    We develop a method for parameter evaluation from incomplete data. Improved estimates of the desired parameters are evaluated step by step, from experiment to experiment by using both Bayesian and informational methods. We make dynamical, improved predictions while the experiments are still going on and keep and interpret information about local fluctuations, which is lost on applying global techniques. The input of information in small packets leads to semi-analytic methods for data processing. An evolution criterion for parameter evaluation, similar to Fisher's theorem of population selection, is derived. We develop direct processing methods, which can be applied to low dimensional systems, semi-analytic methods based on direct or double logarithmic phase expansions, steepest descent approaches, variation and perturbation methods. The techniques are illustrated by developing a method of long-term planning of treatments with oral anticoagulants based on limited clinical data. The efficiency of treatment by oral anticoagulants depends strongly on various anthropometric and genotypic factors, which lead to large variations of the clinical response. We use the clinical data, which accumulates from medical consultations, for extracting improved, incremental information about the statistical properties of the kinetic and anthropometric parameters for a given patient, which in turn is used for making repeated, improved clinical predictions as the treatment proceeds. PMID:18353988

  17. Slope stability susceptibility evaluation parameter (SSEP) rating scheme - An approach for landslide hazard zonation

    NASA Astrophysics Data System (ADS)

    Raghuvanshi, Tarun Kumar; Ibrahim, Jemal; Ayalew, Dereje

    2014-11-01

    In this paper a new slope susceptibility evaluation parameter (SSEP) rating scheme is presented which is developed as an expert evaluation approach for landslide hazard zonation. The SSEP rating scheme is developed by considering intrinsic and external triggering parameters that are responsible for slope instability. The intrinsic parameters which are considered are; slope geometry, slope material (rock or soil type), structural discontinuities, landuse and landcover and groundwater. Besides, external triggering parameters such as, seismicity, rainfall and manmade activities are also considered. For SSEP empirical technique numerical ratings are assigned to each of the intrinsic and triggering parameters on the basis of logical judgments acquired from experience of studies of intrinsic and external triggering factors and their relative impact in inducing instability to the slope. Further, the distribution of maximum SSEP ratings is based on their relative order of importance in contributing instability to the slope. Finally, summation of all ratings for intrinsic and triggering parameter based on actual observation will provide the expected degree of landslide in a given land unit. This information may be utilized to develop a landslide hazard zonation map. The SSEP technique was applied in the area around Wurgessa Kebelle of North Wollo Zonal Administration, Amhara National Regional State in northern Ethiopia, some 490 km from Addis Ababa. The results obtained indicates that 8.33% of the area fall under Moderately hazard and 83.33% fall within High hazard whereas 8.34% of the area fall under Very high hazard. Further, in order to validate the LHZ map prepared during the study, active landslide activities and potential instability areas, delineated through inventory mapping was overlain on it. All active landslide activities and potential instability areas fall within very high and high hazard zone. Thus, the satisfactory agreement confirms the rationality of

  18. [Study of the effect of the microenvironment on magnetic resonance parameters of spin-labeled human serum albumin in a 2-mm ESR range].

    PubMed

    Krinichnyĭ, V I; Grinberg, O Ia; Likhtenshteĭn, G I; Lebedev, Ia S

    1985-01-01

    Basic values of g-tensor and Azz component of HF tensor of two spin labels and spin probe on HSA and nitroxyl radicals HO-15, HO-34 in the solvents of different polarity were measured by 2 mm band ESR of 2 mm range. Magnetic-resonance parameters of liophylized and water-solved spin-labeled HSA were shown to correspond to the parameters of the solvents of the label HO-15 and HO-34 in ethyl alcohol and water. A conclusion was drawn concerning the identity of microenvironment of the nitroxyl fragment of liophylized HSA and frozen solution of the label HO-15 and HO-34 in ethyl alcohol and solvatation of the nitroxyl fragment of spin-labeled HSA and label HO-15 (HO-34) by water molecules.

  19. Comparison of three lines of broiler breeders differing in ascites susceptibility or growth rate. 1. Relationship between acoustic resonance data and embryonic or hatching parameters.

    PubMed

    Tona, K; Kemps, B; Bruggeman, V; Bamelis, F; De Smit, L; Onagbesan, O; De Baerdemaeker, J; Decuypere, E

    2005-09-01

    Ascites is a prevalent cardiovascular disease among modern broilers with negative impacts on production and animal welfare. The peak of mortality due to ascites occurs at the end of the growing period, but the etiology of this problem may start during embryonic development. A few recent reports have demonstrated that the signs of ascites susceptibility are manifested during the late stages of incubation. In the current study, we used a nondestructive method based on egg acoustic resonance parameters [resonant frequency (RF) and damping] to establish a relationship between embryo physiological events during early development in broiler eggs and susceptibility to ascites. The hatching eggs of 3 broiler lines differing in ascites susceptibility were used for this study: ascites-resistant dam line (DAR), ascites-sensitive dam line (DAS), and ascites-sensitive sire line (SASL). These lines were selected on the basis of fast growth, high breast meat yield, and ascites induction at low temperatures such that the order of ascites susceptibility in terms of mortality was SASL > DAS > DAR. Eggs were incubated under standard conditions in forced-draft incubators. We measured egg weights at setting, albumen pH, Haugh units (HU) at setting, and embryo weights at d 11 and 18, at internal pipping (IP), and at hatch. The durations of IP, external pipping (EP), and hatching were also determined. At 2 hourly periods during incubation, egg RF and damping were also measured. There were differences in egg weights between DAR and SASL vs. DAS, but albumen HU, albumen pH, and the ratio of yolk weight to egg weight were similar. There were differences in RF, damping, embryonic growth rates, and hatching events. Changes in resonant frequency and damping, which certainly suggest eggshell differences among lines, were not totally related to variations in physiological events during early and late embryonic development. A comparison between DAR and DAS, between DAS and SASL, or DAR and SASL

  20. Diagnostic accuracy of susceptibility-weighted magnetic resonance imaging for the evaluation of pineal gland calcification

    PubMed Central

    Böker, Sarah M.; Bender, Yvonne Y.; Diederichs, Gerd; Fallenberg, Eva M.; Wagner, Moritz; Hamm, Bernd; Makowski, Marcus R.

    2017-01-01

    Objectives To determine the diagnostic performance of susceptibility-weighted magnetic resonance imaging (SWMR) for the detection of pineal gland calcifications (PGC) compared to conventional magnetic resonance imaging (MRI) sequences, using computed tomography (CT) as a reference standard. Methods 384 patients who received a 1.5 Tesla MRI scan including SWMR sequences and a CT scan of the brain between January 2014 and October 2016 were retrospectively evaluated. 346 patients were included in the analysis, of which 214 showed PGC on CT scans. To assess correlation between imaging modalities, the maximum calcification diameter was used. Sensitivity and specificity and intra- and interobserver reliability were calculated for SWMR and conventional MRI sequences. Results SWMR reached a sensitivity of 95% (95% CI: 91%-97%) and a specificity of 96% (95% CI: 91%-99%) for the detection of PGC, whereas conventional MRI achieved a sensitivity of 43% (95% CI: 36%-50%) and a specificity of 96% (95% CI: 91%-99%). Detection rates for calcifications in SWMR and conventional MRI differed significantly (95% versus 43%, p<0.001). Diameter measurements between SWMR and CT showed a close correlation (R2 = 0.85, p<0.001) with a slight but not significant overestimation of size (SWMR: 6.5 mm ± 2.5; CT: 5.9 mm ± 2.4, p = 0.02). Interobserver-agreement for diameter measurements was excellent on SWMR (ICC = 0.984, p < 0.0001). Conclusions Combining SWMR magnitude and phase information enables the accurate detection of PGC and offers a better diagnostic performance than conventional MRI with CT as a reference standard. PMID:28278291

  1. Parameter-adjusted stochastic resonance system for the aperiodic echo chirp signal in optimal FrFT domain

    NASA Astrophysics Data System (ADS)

    Lin, Li-feng; Yu, Lei; Wang, Huiqi; Zhong, Suchuan

    2017-02-01

    In order to improve the system performance for moving target detection and localization, this paper presents a new aperiodic chirp signal and additive noise driving stochastic dynamical system, in which the internal frequency has the linear variation matching with the driving frequency. By using the fractional Fourier transform (FrFT) operator with the optimal order, the proposed time-domain dynamical system is transformed into the equivalent FrFT-domain system driven by the periodic signal and noise. Therefore, system performance is conveniently analyzed from the view of output signal-to-noise ratio (SNR) in optimal FrFT domain. Simulation results demonstrate that the output SNR, as a function of system parameter, shows the different generalized SR behaviors in the case of various internal parameters of driving chirp signal and external parameters of the moving target.

  2. Contribution of cardiovascular magnetic resonance in the evaluation of coronary arteries

    PubMed Central

    Mavrogeni, Sophie; Markousis-Mavrogenis, George; Kolovou, Genovefa

    2014-01-01

    Cardiovascular magnetic resonance (CMR) allows the nonradiating assessment of coronary arteries; to achieve better image quality cardiorespiratory artefacts should be corrected. Coronary MRA (CMRA) at the moment is indicated only for the detection of abnormal coronary origin, coronary artery ectasia and/or aneurysms (class I indication) and coronary bypass grafts (class II indication). CMRA utilisation for coronary artery disease is not yet part of clinical routine. However, the lack of radiation is of special value for the coronary artery evaluation in children and women. CMRA can assess the proximal part of coronary arteries in almost all cases. The best results have been observed in the evaluation of the left anterior descending and the right coronary artery, while the left circumflex, which is located far away from the coil elements, is frequently imaged with reduced quality, compared to the other two. Different studies detected an increase in wall thickness of the coronaries in patients with type I diabetes and abnormal renal function. Additionally, the non-contrast enhanced T1-weighed images detected the presence of thrombus in acute myocardial infarction. New techniques using delayed gadolinium enhanced imaging promise the direct visualization of inflamed plaques in the coronary arteries. The major advantage of CMR is the potential of an integrated protocol offering assessment of coronary artery anatomy, cardiac function, inflammation and stress perfusion-fibrosis in the same study, providing an individualized clinical profile of patients with heart disease. PMID:25349650

  3. Horizontal Long Axis Imaging Plane for Evaluation of Right Ventricular Function on Cardiac Magnetic Resonance Imaging

    PubMed Central

    Chaturvedi, Abhishek; Whitnah, Joseph; Maki, Jeffrey H; Baran, Timothy; Mitsumori, Lee M

    2016-01-01

    Purpose: The purpose of this study was to evaluate a horizontal long axis (HLA) magnetic resonance imaging (MRI) plane aligned to the long axis of the right ventricular (RV) cavity for functional analysis by comparing the measurement variability and time required for the analysis with that using a short-axis (SAX) image orientation. Materials and Methods: Thirty-four cardiac MRI exams with cine balanced steady-state free precession image stacks in both the SAX and the HLA of the RV (RHLA) were evaluated. Two reviewers independently traced RV endocardial borders on each image of the cine stacks. The time required to complete each set of traces was recorded, and the RV end-diastolic volume, end-systolic volume, and ejection fraction were calculated. Analysis times and RV measurements were compared between the two orientations. Results: Analysis time for each reviewer was significantly shorter for the RHLA stack (reviewer 1 = 6.4 ± 1.8 min, reviewer 2 = 6.0 ± 3.3 min) than for the SAX stack (7.5 ± 2.1 and 6.9 ± 3.6 min, respectively; P < 0.002). Bland–Altman analysis revealed lower mean differences, limits of agreement, and coefficients of variation for RV measurements obtained with the RHLA stack. Conclusions: RV functional analysis using a RHLA stack resulted in shorter analysis times and lower measurement variability than for a SAX stack orientation. PMID:28123842

  4. Evaluation of masticatory activity during unilateral single tooth clenching using muscle functional magnetic resonance imaging.

    PubMed

    Okada, C; Yamaguchi, S; Watanabe, Y; Watanabe, M; Hattori, Y

    2016-08-01

    Masticatory muscle activity during teeth clenching is affected by occlusal pattern. However, few studies have performed simultaneous evaluation of all masticatory activities during teeth clenching under various occlusal conditions. The aim of this study was to use muscle functional magnetic resonance imaging (mfMRI) to evaluate the effects of changes in occlusal point on masticatory activity during single tooth clenching. Changes in mean proton transverse relaxation time (∆T2) as an index of activity in all masticatory muscles during left unilateral clenching at the first molar or first premolar for 1 min were examined in nine healthy volunteers. Bite force was maintained at 40% of the maximum voluntary clenching force. The ∆T2 values of the masseter and lateral pterygoid muscles were analysed separately for superficial and deep layers, and for superior and inferior heads. The ∆T2 values for the ipsilateral deep masseter were significantly lower, and for the superior head of the ipsilateral lateral pterygoid muscles were significantly higher, after left first premolar clenching compared to left first molar clenching. These results quantitatively demonstrate a significant increase in activity of the superior head of the ipsilateral lateral pterygoid muscle and a significant decrease in activity of the ipsilateral deep masseter muscle with forward displacement of the occlusal contact point during unilateral tooth clenching.

  5. Measurement and calculation of the Stark-broadening parameters for the resonance lines of singly ionized calcium and magnesium.

    NASA Technical Reports Server (NTRS)

    Jones, W. W.; Sanchez, A.; Greig, J. R.; Griem, H. R.

    1972-01-01

    The electron-impact-broadened profiles of the resonance lines of singly ionized calcium and magnesium have been measured using an electromagnetically driven shock tube and a rapid-scanning Fabry-Perot spectrometer. For an electron density of 10 to the 17th power per cu cm and a temperature of 19,000 K, we found the Lorentzian half-width of the Ca+ line to be 0.086 A plus or minus 10% and of the Mg+ line to be 0.044 A plus or minus 10%. Using the quantum-mechanical theory of Barnes and Peach and our semiclassical calculation for the calcium lines, we found that the temperature dependence of the theoretical curves is close to that measured, although both theories predict actual values which are somewhat large.

  6. Performance evaluation of the Particle Smoother with Sequential Importance Resampling for soil hydraulic parameter estimation

    NASA Astrophysics Data System (ADS)

    Montzka, C.; Moradkhani, H.; Han, X.; Hendricks Franssen, H. J.; Puetz, T.; Vereecken, H.

    2014-12-01

    An adequate description of soil hydraulic properties is essential for a good performance of hydrological forecasts and soil water fluxes. So far, several studies showed that data assimilation could reduce the parameter uncertainty by considering soil moisture observations. However, these observations and also the model forcings were recorded with a specific measurement error. It seems a logical step to base state updating and parameter estimation on observations made at multiple time steps, in order to reduce the influence of outliers at single time steps given measurement errors and unknown model forcings. Such outliers could result in erroneous state estimation as well as inadequate parameters. This has been one of the reasons to use a smoothing technique as implemented for Bayesian data assimilation methods such as the Ensemble Kalman Filter (i.e. Ensemble Kalman Smoother). In this contribution we present a Particle Smoother (SIR-PS) with sequentially smoothing of particle weights for state and parameter resampling within a time window as opposed to the single time step data assimilation used in filtering techniques. This can be seen as an intermediate variant between a parameter estimation technique using global optimization with estimation of single parameter sets valid for the whole period, and sequential Monte Carlo techniques with estimation of parameter sets evolving from one time step to another. The aims are i) to improve the soil moisture forecast by estimating hydraulic parameters, ii) to reduce the impact of single erroneous model inputs/observations by a smoothing method, and iii) to evaluate the performance of the SIR-PS as opposed to the SIR-PF using different ensemble and smoothing window sizes. In order to validate the performance of the proposed method for real world conditions, experimental data obtained from a two year lysimeter study were used.

  7. Comparison of gradient echo with spin echo magnetic resonance imaging and echocardiography in the evaluation of major aortopulmonary collateral arteries.

    PubMed

    Vick, G W; Wendt, R E; Rokey, R

    1994-05-01

    This study compared gradient echo magnetic resonance imaging, spin echo magnetic resonance imaging, echocardiography, and echocardiography with x-ray cineangiography in the evaluation of major aortopulmonary collateral arteries. Twelve patients (ages 9 months to 35 years, mean 11 +/- 11 years) with known or suspected major aortopulmonary collateral arteries were studied. The aortic insertion and proximal course of 29 major aortopulmonary collateral arteries demonstrated by x-ray contrast angiography were shown in all 29 cases by gradient echo magnetic resonance imaging but in only 23 of the 29 cases by spin echo magnetic resonance imaging. Color Doppler-echocardiography detected aortopulmonary collateral arteries in four patients but did not define the proximal course or distal anatomy. Gradient echo images of distal aortopulmonary collateral anatomy were qualitatively superior to spin echo images. The contrast-to-noise ratio between the vessel lumen and adjacent lung was greater for gradient echo (6.06 +/- 2.91) than for spin echo (1.45 +/- 1.13)(p < 0.05). Gradient echo magnetic resonance imaging is a useful method for identification and characterization of aortopulmonary collateral arteries in patients of all ages and is superior to spin echo magnetic resonance imaging and echocardiography.

  8. A preliminary evaluation of an F100 engine parameter estimation process using flight data

    NASA Technical Reports Server (NTRS)

    Maine, Trindel A.; Gilyard, Glenn B.; Lambert, Heather H.

    1990-01-01

    The parameter estimation algorithm developed for the F100 engine is described. The algorithm is a two-step process. The first step consists of a Kalman filter estimation of five deterioration parameters, which model the off-nominal behavior of the engine during flight. The second step is based on a simplified steady-state model of the compact engine model (CEM). In this step, the control vector in the CEM is augmented by the deterioration parameters estimated in the first step. The results of an evaluation made using flight data from the F-15 aircraft are presented, indicating that the algorithm can provide reasonable estimates of engine variables for an advanced propulsion control law development.

  9. Monte Carlo evaluation of biological variation: Random generation of correlated non-Gaussian model parameters

    NASA Astrophysics Data System (ADS)

    Hertog, Maarten L. A. T. M.; Scheerlinck, Nico; Nicolaï, Bart M.

    2009-01-01

    When modelling the behaviour of horticultural products, demonstrating large sources of biological variation, we often run into the issue of non-Gaussian distributed model parameters. This work presents an algorithm to reproduce such correlated non-Gaussian model parameters for use with Monte Carlo simulations. The algorithm works around the problem of non-Gaussian distributions by transforming the observed non-Gaussian probability distributions using a proposed SKN-distribution function before applying the covariance decomposition algorithm to generate Gaussian random co-varying parameter sets. The proposed SKN-distribution function is based on the standard Gaussian distribution function and can exhibit different degrees of both skewness and kurtosis. This technique is demonstrated using a case study on modelling the ripening of tomato fruit evaluating the propagation of biological variation with time.

  10. A parameter estimation algorithm for spatial sine testing - Theory and evaluation

    NASA Technical Reports Server (NTRS)

    Rost, R. W.; Deblauwe, F.

    1992-01-01

    This paper presents the theory and an evaluation of a spatial sine testing parameter estimation algorithm that uses directly the measured forced mode of vibration and the measured force vector. The parameter estimation algorithm uses an ARMA model and a recursive QR algorithm is applied for data reduction. In this first evaluation, the algorithm has been applied to a frequency response matrix (which is a particular set of forced mode of vibration) using a sliding frequency window. The objective of the sliding frequency window is to execute the analysis simultaneously with the data acquisition. Since the pole values and the modal density are obtained from this analysis during the acquisition, the analysis information can be used to help determine the forcing vectors during the experimental data acquisition.

  11. Temperature evaluation of traveling-wave ultrasonic motor considering interaction between temperature rise and motor parameters.

    PubMed

    Li, Shiyang; Ou, Wenchu; Yang, Ming; Guo, Chao; Lu, Cunyue; Hu, Junhui

    2015-03-01

    In this paper, a novel model for evaluating the temperature of traveling-wave ultrasonic motor (TWUSM) is developed. The proposed model, where the interaction between the temperature rise and motor parameters is considered, differs from the previous reported models with constant parameters. In this model, losses and temperature rises of the motor were evaluated based on the temperature-related varying parameters: the feedback voltage Vaux of the stator, dielectric permittivity ɛ and dielectric loss factor tanδ. At each new temperature, Vaux, ɛ and tanδ were updated. The feasibility and effectiveness of this proposed model was verified by comparing the predicted temperatures with the measured one. The effects of driving voltage, driving frequency and ambient temperature on the predicted temperature were also analyzed. The results show that the proposed model has more accurate predicted temperature than that with constant parameters. This will be very useful for the optimal design, reducing the heat loss, improvement of control and reliability life of TWUSM.

  12. Effects of chiral fragrances on human autonomic nervous system parameters and self-evaluation.

    PubMed

    Heuberger, E; Hongratanaworakit, T; Böhm, C; Weber, R; Buchbauer, G

    2001-03-01

    The effects of chiral fragrances (enantiomers of limonene and carvone) on the human autonomic nervous system (ANS) and on self-evaluation were studied in 20 healthy volunteers. Each fragrance was administered to each subject by inhalation using an A-A-B design. Individuals were tested in four separate sessions; in one session one fragrance was administered. ANS parameters recorded were skin temperature, skin conductance, breathing rate, pulse rate, blood oxygen saturation and systolic as well as diastolic blood pressure. Subjective experience was assessed in terms of mood, calmness and alertness on visual analog scales. In addition, fragrances were rated in terms of pleasantness, intensity and stimulating property. Inhalation of (+)-limonene led to increased systolic blood pressure, subjective alertness and restlessness. Inhalation of (-)-limonene caused an increase in systolic blood pressure but had no effects on psychological parameters. Inhalation of (-)-carvone caused increases in pulse rate, diastolic blood pressure and subjective restlessness. After inhalation of (+)-carvone increased levels of systolic as well as diastolic blood pressure were observed. Correlational analyses revealed that changes in both ANS parameters and self-evaluation were in part related to subjective evaluation of the odor and suggest that both pharmacological and psychological mechanisms are involved in the observed effects. In conclusion, the present study indicates that: (i) prolonged inhalation of fragrances influences ANS parameters as well as mental and emotional conditions; (ii) effects of fragrances are in part based on subjective evaluation of odor; (iii) chirality of odor molecules seems to be a central factor with respect to the biological activity of fragrances.

  13. Assessment of cardiac parameters in evaluation of cardiac functions in patients with thalassemia major.

    PubMed

    Oztarhan, Kazim; Delibas, Yavuz; Salcioglu, Zafer; Kaya, Guldemet; Bakari, Suleyman; Bornaun, Helen; Aydogan, Gonul

    2012-04-01

    The aim of the study was to evaluate cardiac function and early cardiac dysfunction of patients followed as thalassemia major. In this study, the authors compared 100 patients, diagnosed as thalassemia major with mean age 11.84 ± 4.35, with 60 healthy control subjects at the same age between 2008 and 2011. Early diagnosis of iron overload that may occur after repeated transfusions is important in this patient group. To detect early iron accumulation, the authors compared ferritin with the echo findings, the 24-hour Holter, and cardiac magnetic resonance imaging (MRI) T2* values in the patients of same age and sex, treated with chelators, without heart failure, nonsplenectomized, and do not differ in the presence of hepatitis C. Ferritin levels, left ventricular systolic functions (ejection fraction [EF], shortening fraction [SF]), left ventricular measurements, left ventricular diastolic functions, T2* image on cardiac magnetic resonance, heart rate variables in 24 hours, and Holter rhythm were evaluated to show the early failure of cardiac functions. In this study the authors confirmed that iron-related cardiac toxicity damages electrical activity earlier than myocardial contractility. Left ventricular diastolic diameter (LVDd), left ventricular mass (LVM), and LV systolic diameter (LVDs) levels were significantly higher in the patient group with ectopia. Patients with ectopia are the ones in whom LVM and LVDd are increased. In thalassemia major patients with ectopia, LF/HF ratio was markedly increased, QTc dispersion was clearly found higher in patients with ectopia rather than nonectopic patients. The standard deviation all normal RR interval series (SDNN) was found clearly lower in thalassemia major group with ectopia than control group because it is assumed that increase in cardiac sympathetic neuronal activity is related to exposure to chronic diastolic and systolic failure.

  14. Evaluation of the anterolateral ligament of the knee by means of magnetic resonance examination☆

    PubMed Central

    Helito, Camilo Partezani; Demange, Marco Kawamura; Helito, Paulo Victor Partezani; Costa, Hugo Pereira; Bonadio, Marcelo Batista; Pecora, Jose Ricardo; Rodrigues, Marcelo Bordalo; Camanho, Gilberto Luis

    2015-01-01

    Objective To evaluate the presence of the anterolateral ligament (ALL) of the knee in magnetic resonance imaging (MRI) examinations. Methods Thirty-three MRI examinations on patients’ knees that were done because of indications unrelated to ligament instability or trauma were evaluated. T1-weighted images in the sagittal plane and T2-weighted images with fat saturation in the axial, sagittal and coronal planes were obtained. The images were evaluated by two radiologists with experience of musculoskeletal pathological conditions. In assessing ligament visibility, we divided the analysis into three portions of the ligament: from its origin in the femur to its point of bifurcation; from the bifurcation to the meniscal insertion; and from the bifurcation to the tibial insertion. The capacity to view the ligament in each of its portions and overall was taken to be a dichotomous categorical variable (yes or no). Results The ALL was viewed with signal characteristics similar to those of the other ligament structures of the knee, with T2 hyposignal with fat saturation. The main plane in which the ligament was viewed was the coronal plane. Some portion of the ligament was viewed clearly in 27 knees (81.8%). The meniscal portion was evident in 25 knees (75.7%), the femoral portion in 23 (69.6%) and the tibial portion in 13 (39.3%). The three portions were viewed together in 11 knees (33.3%). Conclusion The anterolateral ligament of the knee is best viewed in sequences in the coronal plane. The ligament was completely characterized in 33.3% of the cases. The meniscal portion was the part most easily identified and the tibial portion was the part least encountered. PMID:26229919

  15. Magnetic Resonance Imaging (MRI) Evaluation for Anterior Disc Displacement of the Temporomandibular Joint

    PubMed Central

    Yang, Zhongjun; Wang, Mingguo; Ma, Yingwei; Lai, Qingguo; Tong, Dongdong; Zhang, Fenghe; Dong, Lili

    2017-01-01

    Background Magnetic resonance imaging (MRI) is the criterion standard imaging technique for visualization of the temporomandibular joint (TMJ) region, and is currently considered the optimum modality for comprehensive evaluation in patients with temporomandibular joint disorder (TMD). This study was aimed at finding the value of MRI in pre-clinical diagnosis of TMJ disc displacement. Material/Methods Patients primarily diagnosed as having anterior disc displacement by clinical symptoms and X-ray were selected in the present study. MRI was used to evaluate surrounding anatomical structures and position, as well as morphological and signal intensity change between patients and normal controls. Results Posterior band position was significantly different between the patient group and control group. At the maximum opened-mouth position, the location of disc intermediate zone returned to normal. At closed-mouth position, the thickness of anterior and middle, but not posterior, band increased. The motion range of the condyle in the anterior disc displacement without reduction (ADDWR) patient group was significantly less than the value in the anterior disc displacement with reduction (ADDR) patient group and the control group. Whether at closed-mouth position or maximum opened-mouth position, the exudate volume in the patient group was greater than in the normal group. Conclusions MRI can be successfully used to evaluate multiple morphological changes at different mouth positions of normal volunteers and patients. The disc-condyle relationship can serve as an important indicator in assessing anterior disc displacement, and can be used to distinguish disc displacement with or without reduction. PMID:28176754

  16. Subsonic flight test evaluation of a propulsion system parameter estimation process for the F100 engine

    NASA Technical Reports Server (NTRS)

    Orme, John S.; Gilyard, Glenn B.

    1992-01-01

    Integrated engine-airframe optimal control technology may significantly improve aircraft performance. This technology requires a reliable and accurate parameter estimator to predict unmeasured variables. To develop this technology base, NASA Dryden Flight Research Facility (Edwards, CA), McDonnell Aircraft Company (St. Louis, MO), and Pratt & Whitney (West Palm Beach, FL) have developed and flight-tested an adaptive performance seeking control system which optimizes the quasi-steady-state performance of the F-15 propulsion system. This paper presents flight and ground test evaluations of the propulsion system parameter estimation process used by the performance seeking control system. The estimator consists of a compact propulsion system model and an extended Kalman filter. The extended Laman filter estimates five engine component deviation parameters from measured inputs. The compact model uses measurements and Kalman-filter estimates as inputs to predict unmeasured propulsion parameters such as net propulsive force and fan stall margin. The ability to track trends and estimate absolute values of propulsion system parameters was demonstrated. For example, thrust stand results show a good correlation, especially in trends, between the performance seeking control estimated and measured thrust.

  17. Evaluation of a classification method for biodegradable solid wastes using anaerobic degradation parameters.

    PubMed

    Zheng, Wei; Phoungthong, Khamphe; Lü, Fan; Shao, Li-Ming; He, Pin-Jing

    2013-12-01

    We studied the biochemical and anaerobic degradation characteristics of 29 types of materials to evaluate the effects of a physical composition classification method for degradable solid waste on the computation of anaerobic degradation parameters, including the methane yield potential (L0), anaerobic decay rate (k), and carbon sequestration factor (CSF). Biochemical methane potential tests were conducted to determine the anaerobic degradation parameters of each material. The results indicated that the anaerobic degradation parameters of nut waste were quite different from those of other food waste and nut waste was classified separately. Paper was subdivided into two categories according to its lignin content: degradable paper with lignin content of <0.05 g g VS(-1), and refractory paper with lignin content >0.15 g g VS(-1). The L0, k, and CSF parameters of leaves, a type of garden waste, were similar to those of grass. This classification method for degradable solid waste may provide a theoretical basis that facilitates the more accurate calculation of anaerobic degradation parameters.

  18. Evaluation of unconfined-aquifer parameters from pumping test data by nonlinear least squares

    USGS Publications Warehouse

    Heidari, M.; Moench, A.

    1997-01-01

    Nonlinear least squares (NLS) with automatic differentiation was used to estimate aquifer parameters from drawdown data obtained from published pumping tests conducted in homogeneous, water-table aquifers. The method is based on a technique that seeks to minimize the squares of residuals between observed and calculated drawdown subject to bounds that are placed on the parameter of interest. The analytical model developed by Neuman for flow to a partially penetrating well of infinitesimal diameter situated in an infinite, homogeneous and anisotropic aquifer was used to obtain calculated drawdown. NLS was first applied to synthetic drawdown data from a hypothetical but realistic aquifer to demonstrate that the relevant hydraulic parameters (storativity, specific yield, and horizontal and vertical hydraulic conductivity) can be evaluated accurately. Next the method was used to estimate the parameters at three field sites with widely varying hydraulic properties. NLS produced unbiased estimates of the aquifer parameters that are close to the estimates obtained with the same data using a visual curve-matching approach. Small differences in the estimates are a consequence of subjective interpretation introduced in the visual approach.

  19. Resonant alteration of propagation in guiding structures with complex Robin parameter and its magnetic-field-induced restoration

    SciTech Connect

    Olendski, O.

    2011-06-15

    Highlights: > Solutions of the wave equation are analyzed for the confined circular geometry with complex Robin boundary conditions. > Sharp extremum is found in the energy dependence on the imaginary part of the extrapolation length. > Nonzero real part of the Robin length or/and magnetic field wipe out the resonance. - Abstract: Solutions of the scalar Helmholtz wave equation are derived for the analysis of the transport and thermodynamic properties of the two-dimensional disk and three-dimensional infinitely long straight wire in the external uniform longitudinal magnetic field B under the assumption that the Robin boundary condition contains extrapolation length {Lambda} with nonzero imaginary part {Lambda}{sub i}. As a result of this complexity, the self-adjointness of the Hamiltonian is lost, its eigenvalues E become complex too and the discrete bound states of the disk characteristic for the real {Lambda} turn into the corresponding quasibound states with their lifetime defined by the eigenenergies imaginary parts E{sub i}. Accordingly, the longitudinal flux undergoes an alteration as it flows along the wire with its attenuation/amplification being E{sub i}-dependent too. It is shown that, for zero magnetic field, the component E{sub i} as a function of the Robin imaginary part exhibits a pronounced sharp extremum with its magnitude being the largest for the zero real part {Lambda}{sub r} of the extrapolation length. Increasing magnitude of {Lambda}{sub r} quenches the E{sub i} - {Lambda}{sub i} resonance and at very large {Lambda}{sub r} the eigenenergies E approach the asymptotic real values independent of {Lambda}{sub i}. The extremum is also wiped out by the magnetic field when, for the large B, the energies tend to the Landau levels. Mathematical and physical interpretations of the obtained results are provided; in particular, it is shown that the finite lifetime of the disk quasibound states stems from the {Lambda}{sub i}-induced currents flowing

  20. A simple general method to evaluate intra-specific transpiration parameters within and among seedling families.

    PubMed

    Leonardi, Stefano; Piovani, Paolo; Magnani, Federico; Menozzi, Paolo

    2006-08-01

    A method to evaluate the genetic control of plant response to increasing soil water deficit is proposed. A description of single tree transpiration behavior was obtained considering parameters independent from air and soil conditions. We removed environmental effects by using two approaches: the normalization of drought data to control (watered) plants and the fitting of a process model. We analyzed the transpiration of 475 4-year-old European beech seedlings, belonging to eight full-sib families. Approximately, one-third of the seedlings were kept in well-watered conditions while the others were exposed to drought for 14 days. Daily plant transpiration was estimated as the difference between two subsequent gravimetric measurements. A mechanistic model was fitted to transpiration data separately for each tree. In the model, the relationship of transpiration with vapor pressure deficit and soil water deficit of each tree is modulated by three parameters: maximum leaf conductance (gM1), maximum transpiration in well-watered soil conditions E(M0)1 and a parameter describing stomatal sensitivity to soil water deficit (c). The model successfully fitted most single tree data and a distribution of estimates for the three parameters (gM1, E(M0)1 and c) was obtained. Predicted transpiration values were in good agreement with observed data (R (2) = 0.86). The model approach produced parameters significantly correlated with those of the "normalization to control" approach. Estimated parameters vary considerably among trees, suggesting the presence of individual differences in stomatal behavior and response to drought. In spite of a large among tree (within family) variation, the among families component for gM1, E(M0)1 and c explained 9.5, 3.3 and 0.1% of total parameters variation suggesting a significant genetic control of transpiration processes.

  1. Uncertainty evaluation of nuclear reaction model parameters using integral and microscopic measurements. Covariances evaluation with CONRAD code

    NASA Astrophysics Data System (ADS)

    de Saint Jean, C.; Habert, B.; Archier, P.; Noguere, G.; Bernard, D.; Tommasi, J.; Blaise, P.

    2010-10-01

    In the [eV;MeV] energy range, modelling of the neutron induced reactions are based on nuclear reaction models having parameters. Estimation of co-variances on cross sections or on nuclear reaction model parameters is a recurrent puzzle in nuclear data evaluation. Major breakthroughs were asked by nuclear reactor physicists to assess proper uncertainties to be used in applications. In this paper, mathematical methods developped in the CONRAD code[2] will be presented to explain the treatment of all type of uncertainties, including experimental ones (statistical and systematic) and propagate them to nuclear reaction model parameters or cross sections. Marginalization procedure will thus be exposed using analytical or Monte-Carlo solutions. Furthermore, one major drawback found by reactor physicist is the fact that integral or analytical experiments (reactor mock-up or simple integral experiment, e.g. ICSBEP, …) were not taken into account sufficiently soon in the evaluation process to remove discrepancies. In this paper, we will describe a mathematical framework to take into account properly this kind of information.

  2. Multi-Group Formulation of the Temperature-Dependent Resonance Scattering Model and its Impact on Reactor Core Parameters

    SciTech Connect

    Ghrayeb, Shadi Z.; Ougouag, Abderrafi M.; Ouisloumen, Mohamed; Ivanov, Kostadin N.

    2014-01-01

    A multi-group formulation for the exact neutron elastic scattering kernel is developed. It incorporates the neutron up-scattering effects, stemming from lattice atoms thermal motion and accounts for it within the resulting effective nuclear cross-section data. The effects pertain essentially to resonant scattering off of heavy nuclei. The formulation, implemented into a standalone code, produces effective nuclear scattering data that are then supplied directly into the DRAGON lattice physics code where the effects on Doppler Reactivity and neutron flux are demonstrated. The correct accounting for the crystal lattice effects influences the estimated values for the probability of neutron absorption and scattering, which in turn affect the estimation of core reactivity and burnup characteristics. The results show an increase in values of Doppler temperature feedback coefficients up to -10% for UOX and MOX LWR fuels compared to the corresponding values derived using the traditional asymptotic elastic scattering kernel. This paper also summarizes the results done on this topic to date.

  3. Litchi freshness rapid non-destructive evaluating method using electronic nose and non-linear dynamics stochastic resonance model.

    PubMed

    Ying, Xiaoguo; Liu, Wei; Hui, Guohua

    2015-01-01

    In this paper, litchi freshness rapid non-destructive evaluating method using electronic nose (e-nose) and non-linear stochastic resonance (SR) was proposed. EN responses to litchi samples were continuously detected for 6 d Principal component analysis (PCA) and non-linear stochastic resonance (SR) methods were utilized to analyze EN detection data. PCA method could not totally discriminate litchi samples, while SR signal-to-noise ratio (SNR) eigen spectrum successfully discriminated all litchi samples. Litchi freshness predictive model developed using SNR eigen values shows high predictive accuracy with regression coefficients R(2) = 0 .99396.

  4. Evaluation of the photoelectric performance parameters measurement for electron multiplying CCD

    NASA Astrophysics Data System (ADS)

    Fang, Jie; Zhang, Wenwen; Gao, Jin; Li, Chaowei; Chen, Qian; Gu, Guohua

    2016-10-01

    The measurement of the electron multiplying CCD(EMCCD) photoelectric performance parameters plays an important role in the development of the chip and imaging system. Measurement uncertainty is an important index to evaluate the quality of the measurement results. A measurement platform for EMCCD photoelectric performance parameters is set up. An EMCCD camera's photoelectric performance parameters are measured based on photon transfer technique and the uncertainty of the measurement results is analyzed. Based on the method of GUM, the influences of the integrating sphere light source stability, EMCCD camera electronics system stability, installation posture, stray light in dark environment, camera's digital resolution and measurement sampling on the measurement results are analyzed. Based on the theoretical model of different photoelectric performance parameters, the uncertainty sources are discussed. The combined standard uncertainty is determined by the type A uncertainty and the type B uncertainty. The uncertainty evaluation model is established for the measurement of EMCCD photoelectric performance parameters, including convert gain, readout noise, full well, signal to noise ratio and multiplication gain. The uncertainty of the measurement results is calculated by using the established model. At last, we get the following results: relative standard uncertainty of the convert gain is 0.637% (k = 1), relative standard uncertainty of the readout noise is 0.653% (k = 1), relative standard uncertainty of the full well is 2.384% (k = 1), relative standard uncertainty of the signal to noise ratio is 2.301% (k = 1) and relative standard uncertainty of the multiplication gain is 1.259% (k = 1). The above uncertainty results show that the measurement results of this paper are accurate and reliable.

  5. Combustion of pistachio shell: physicochemical characterization and evaluation of kinetic parameters.

    PubMed

    da Silva, Jean Constantino Gomes; Alves, José Luiz Francisco; Galdino, Wendell Venicio de Araujo; Moreira, Regina de Fátima Peralta Muniz; José, Humberto Jorge; de Sena, Rennio Felix; Andersen, Silvia Layara Floriani

    2017-04-06

    The study of different renewable energy sources has been intensifying due to the current climate changes; therefore, the present work had the objective to characterize physicochemically the pistachio shell waste and evaluate kinetic parameters of its combustion. The pistachio shell was characterized through proximate analysis, ultimate analysis, SEM, and FTIR. The thermal and kinetic behaviors were evaluated by a thermogravimetric analyzer under oxidant atmosphere between room temperature and 1000 °C, in which the process was performed in three different heating rates (20, 30, and 40 °C min(-1)). The combustion of the pistachio shell presented two regions in the derivative thermogravimetric curves, where the first represents the devolatilization of volatile matter compounds and the second one is associated to the biochar oxidation. These zones were considered for the evaluation of the kinetic parameters E a , A, and f(α) by the modified method of Coats-Redfern, compensation effect, and master plot, respectively. The kinetic parameters for zone 1 were E a1 = 84.11 kJ mol(-1), A 1 = 6.39 × 10(6) min(-1), and f(α)1 = 3(1 - α)(2/3), while for zone 2, the kinetic parameters were E a2 = 37.47 kJ mol(-1), A 2 = 57.14 min(-1), and f(α)2 = 2(1 - α)(1/2).

  6. Evaluation of shoulder balance in the normal adolescent population and its correlation with radiological parameters.

    PubMed

    Akel, Ibrahim; Pekmezci, Murat; Hayran, Mutlu; Genc, Yasemin; Kocak, Ozgur; Derman, Orhan; Erdoğan, Ilkay; Yazici, Muharrem

    2008-03-01

    A descriptive clinical study in healthy adolescents was done to evaluate the clinical shoulder balance and analyze the correlation between clinical and radiological parameters which are currently used to evaluate shoulder balance. In addition to trunk shift and rib hump, shoulder balance is one of the criteria that are used to evaluate the outcomes in spinal deformity surgery. Several methods have been proposed to evaluate the shoulder balance in scoliotic patients; however, there is no uniformity to these methods in the current literature. Patients who applied to pediatric clinic without musculoskeletal pathology formed the patient population. Volunteers were asked to fill out a questionnaire assessing shoulder balance perception and had their clinical photograph taken simultaneously with a P-A chest X-ray. The clinical shoulder balance was evaluated through analysis of the clinical photograph. The X-rays were used to evaluate the radiological shoulder balance. The evaluated parameters included coracoid height difference (CHD), clavicular angle (CA), the clavicle-rib cage intersection difference (CRID), clavicular tilt angle difference (CTAD), and T1-tilt. The study group was composed of 48 male and 43 female patients with an average age of 13.6 +/- 2.1 (10-18) years. In the questionnaire, all patients stated that their shoulders were level. The digital photographs revealed that only 17(18.7%) adolescents had absolutely level shoulders. The average height difference between shoulders was 7.5 +/- 5.8 mm. The average CHD was 6.9 +/- 5.8 mm, average CA was 2.2 +/- 1.7 degrees , average CRID was 4.8 +/- 3.6 mm, average CTAD was 4 +/- 3.2 degrees , and average T1-tilt was 1.3 +/- 1.4 degrees . CHD, CA, and CRID demonstrated high correlation with clinical pictures, whereas CTAD demonstrated moderate and T1-tilt demonstrated only mild correlation. The radiological parameters used to evaluate the shoulder balance correlate with the clinical appearance. Contrary to popular

  7. Subtypes evaluation of motor dysfunction in Parkinson's disease using neuromelanin-sensitive magnetic resonance imaging.

    PubMed

    Xiang, Yuanyuan; Gong, Tao; Wu, Junwei; Li, Jifeng; Chen, Yan; Wang, Yongxiang; Li, Shan; Cong, Lin; Lin, Youting; Han, Yuxiang; Yin, Ling; Wang, Guangbin; Du, Yifeng

    2017-01-18

    Parkinson's disease (PD) is characterized by the loss of neuromelanin (NM)-containing neurons in the substantia nigra pars compacta (SNc), and it is divided into two motor subtypes: the postural instability gait difficulty (PIGD) and the tremor dominant (TD) subtypes. With NM-sensitive Magnetic Resonance Imaging (NM-MRI), investigators have been able to accurately detect signal attenuation in SNc of PD; however, the difference of NM loss between PIGD and TD subtypes is still unclear. Thus, the aim of this study was to evaluate the differences in NM-MRI between PD motor subtypes. PD patients were classified into PIGD (n=14) and TD groups (n=9); 20 age and sex matched controls were recruited. We compared the signal intensity contrast ratios in medial and lateral regions of the SNc using NM-MRI in PIGD, TD, and controls, respectively. Remarkable signal attenuation was observed in the lateral part of SNc in PD when compared with the controls, and we were able to detect more severe signal attenuation in the medial part of SNc in PIGD patients in comparison with that in the TD group. Also, the medial part of SNc, ipsilateral to the most clinically affected side, showed the highest power to discriminate the PD motor subtypes (AUC, 81%; sensitivity, 71.4%; specificity, 77.8%). Our results indicated a potential diagnostic value of NM-MRI to discriminate the PD motor subtypes, providing new evidence for the neuropathology-based differences between the two subtypes.

  8. The Emerging Role of Cardiovascular Magnetic Resonance Imaging in the Evaluation of Metabolic Cardiomyopathies.

    PubMed

    Mavrogeni, S; Markousis-Mavrogenis, G; Markussis, V; Kolovou, G

    2015-08-01

    The aim of this review is to discuss the role of Cardiovascular Magnetic Resonance (CMR) in the diagnosis, risk stratification, and follow-up of metabolic cardiomyopathies. The classification of myocardial diseases, proposed by WHO/ISFC task force, distinguished specific cardiomyopathies, caused by metabolic disorders, into 4 types: 1) endocrine disorders, 2) storage or infiltration disorders (amyloidosis, hemochromatosis and familial storage disorders), 3) nutritional disorders (Kwashiorkor, beri-beri, obesity, and alcohol), and 4) diabetic heart. Thyroid disease, pheochromocytoma, and growth hormone excess or deficiency may contribute to usually reversible dilated cardiomyopathy. Glucogen storage diseases can be presented with myopathy, liver, and heart failure. Lysosomal storage diseases can provoke cardiac hypertrophy, mimicking hypertrophic cardiomyopathy and arrhythmias. Hereditary hemochromatosis, an inherited disorder of iron metabolism, leads to tissue iron overload in different organs, including the heart. Cardiac amyloidosis is the result of amyloid deposition in the heart, formed from breakdown of normal or abnormal proteins that leads to increased heart stiffness, restrictive cardiomyopathy, and heart failure. Finally, nutritional disturbances and metabolic diseases, such as Kwashiorkor, beri-beri, obesity, alcohol consumption, and diabetes mellitus may also lead to severe cardiac dysfunction. CMR, through its capability to reliably assess anatomy, function, inflammation, rest-stress myocardial perfusion, myocardial fibrosis, aortic distensibility, iron and/or fat deposition can serve as an excellent tool for early diagnosis of heart involvement, risk stratification, treatment evaluation, and long term follow-up of patients with metabolic cardiomyopathies.

  9. Radiographic Evaluation of Valvular Heart Disease With Computed Tomography and Magnetic Resonance Correlation.

    PubMed

    Lempel, Jason K; Bolen, Michael A; Renapurkar, Rahul D; Azok, Joseph T; White, Charles S

    2016-09-01

    Valvular heart disease is a group of complex entities with varying etiologies and clinical presentations. There are a number of imaging tools available to supplement clinical evaluation of suspected valvular heart disease, with echocardiography being the most common and clinically established, and more recent emergence of computed tomography and magnetic resonance imaging as additional supportive techniques. Yet even with these newer and more sophisticated modalities, chest radiography remains one of the earliest and most common diagnostic examinations performed during the triage of patients with suspected cardiac dysfunction. Recognizing the anatomic and pathologic features of cardiac radiography including the heart's adaptation to varying hemodynamic changes can provide clues to the radiologist regarding the underlying etiology. In this article, we will elucidate several principles relating to chamber modifications in response to pressure and volume overload as well as radiographic appearances associated with pulmonary fluid status and cardiac dysfunction. We will also present a pattern approach to optimize analysis of the chest radiograph for valvular heart disease, which will help guide the radiologist down a differential diagnostic pathway and create a more meaningful clinical report.

  10. Evaluation of crocin and curcumin affinity on mushroom tyrosinase using surface plasmon resonance.

    PubMed

    Patil, Sushama; Srinivas, Sistla; Jadhav, Jyoti

    2014-04-01

    Tyrosinase inhibitors have potential applications in the cosmetics and food industries for preventing browning reactions and also as therapeutic drugs for neurodegenerative diseases such as Parkinson's. In this article, crocin and curcumin were evaluated as mushroom tyrosinase inhibitors. Results showed that, both compounds strongly inhibited the diphenolase activity than monophenolase. The IC50 values for diphenolase activity were estimated to be 0.11 mM and 0.18 mM for crocin and curcumin respectively. The binding kinetics of crocin and curcumin was studied with mushroom tyrosinase using surface plasmon resonance (SPR). Tyrosinase was immobilized on the gold surface of a Biacore sensor chip through amine coupling. Binding of inhibitors was analyzed by SPR without the need to further modify the surface or the use of other reagents. The binding constant KD (M) for mushroom tyrosinase obtained was 1.21×10(-4) M for crocin and 1.64×10(-4) M for curcumin, while showing a higher affinity for L-DOPA 1.95×10(-8) M, a substrate for tyrosinase (positive control). The study reveals the SPR sensor's ability to detect binding of the inhibitors.

  11. Protection of dehydrated chicken meat by natural antioxidants as evaluated by electron spin resonance spectrometry.

    PubMed

    Nissen, L R; Månsson, L; Bertelsen, G; Huynh-Ba, T; Skibsted, L H

    2000-11-01

    Dehydrated chicken meat (a(w) = 0.20-0.35) made from mechanically deboned chicken necks can be protected against oxidative deterioration during storage by rosemary extract (at a sensory acceptable level of 1000 ppm, incorporated prior to drying). The efficiency of the rosemary extract was similar to that obtained by synthetic antioxidants in a reference product (70 ppm butylated hydroxyanisole and 70 ppm octyl gallate). Tea extract and coffee extract were less efficient than rosemary and synthetic antioxidants. Among the natural antioxidants tested, grape skin extract provided the least protection against oxidative changes in dehydrated chicken meat. Radicals in the product, quantified by direct measurement by electron spin resonance (ESR) spectrometry, developed similarly to headspace ethane, pentane, and hexanal, and to oxygen depletion both in unprotected and protected products. The ESR signal intensity and headspace hexanal both correlated with the sensory descriptor "rancidity" as evaluated by a trained sensory panel. Hexanal, as a secondary lipid oxidation product, showed an exponential dependence on the level of radicals in the product in agreement with a chain reaction mechanism for autoxidation, and direct ESR measurement may be used in quality control of dehydrated food products.

  12. Resonance Raman Spectroscopic Evaluation of Skin Carotenoids as a Biomarker of Carotenoid Status for Human Studies

    PubMed Central

    Mayne, Susan T.; Cartmel, Brenda; Scarmo, Stephanie; Jahns, Lisa; Ermakov, Igor V.; Gellermann, Werner

    2013-01-01

    Resonance Raman Spectroscopy (RRS) is a non-invasive method that has been developed to assess carotenoid status in human tissues including human skin in vivo. Skin carotenoid status has been suggested as a promising biomarker for human studies. This manuscript describes research done relevant to the development of this biomarker, including its reproducibility, validity, feasibility for use in field settings, and factors that affect the biomarker such as diet, smoking, and adiposity. Recent studies have evaluated the response of the biomarker to controlled carotenoid interventions, both supplement-based and dietary [e.g., provision of a high-carotenoid fruit and vegetable (F/V)-enriched diet], demonstrating consistent response to intervention. The totality of evidence supports the use of skin carotenoid status as an objective biomarker of F/V intake, although in the cross-sectional setting, diet explains only some of the variation in this biomarker. However, this limitation is also a strength in that skin carotenoids may effectively serve as an integrated biomarker of health, with higher status reflecting greater F/V intake, lack of smoking, and lack of adiposity. Thus, this biomarker holds promise as both a health biomarker and an objective indicator of F/V intake, supporting its further development and utilization for medical and public health purposes. PMID:23823930

  13. Microvascular Obstruction Evaluation Using Cardiovascular Magnetic Resonance (CMR) in ST-Elevated Myocardial Infarction (STEMI) Patients

    PubMed Central

    Piotrowska-Kownacka, Dorota; Kownacki, Łukasz; Kochman, Janusz; Kołodzińska, Agnieszka; Kobylecka, Małgorzata; Królicki, Leszek

    2015-01-01

    Summary Backround Restoration of blood flow in epicardial coronary artery in patients with acute myocardial infarction can, but does not have to restore efficient blood flow in coronary circulation. The aim of the study was a direct comparison of microvascular obstruction (MVO) detected by rest and stress perfusion imaging and gadolinium enhancement obtained 2 min. (early MVO) and 15 min. (delayed MVO) post contrast. Material/Methods 106 patients with first anterior myocardial infarction were studied. Cardiovascular magnetic resonance (CMR) was performed 5±2 days after primary percutaneous coronary intervention (pPCI). Stress and rest perfusion imaging was performed as well as early and delayed gadolinium enhancement and systolic function assessment. Scoring of segmental function, perfusion defect, MVO and scar transmurality was performed in 16 segment left ventricular model. Results The prevalence of MVO varies significantly between imaging techniques ranging from 48.8% for delayed MVO to 94% with stress perfusion. Median sum of scores was significantly different for each technique: stress perfusion 13 (7; 18), rest perfusion 3 (0.5; 6), early MVO 3 (0; 8), delayed MVO 0 (0; 4); p<0.05. Infarct size, stress and rest perfusion defects were independent predictors of LV EF at discharge from hospital. Conclusions Imaging protocol has a significant impact on MVO results. The study is the first to describe a stress-induced MVO in STEMI patients. Further research is needed to evaluate its impact on a long term prognosis. PMID:26740825

  14. Resonance Raman spectroscopic evaluation of skin carotenoids as a biomarker of carotenoid status for human studies.

    PubMed

    Mayne, Susan T; Cartmel, Brenda; Scarmo, Stephanie; Jahns, Lisa; Ermakov, Igor V; Gellermann, Werner

    2013-11-15

    Resonance Raman spectroscopy (RRS) is a non-invasive method that has been developed to assess carotenoid status in human tissues including human skin in vivo. Skin carotenoid status has been suggested as a promising biomarker for human studies. This manuscript describes research done relevant to the development of this biomarker, including its reproducibility, validity, feasibility for use in field settings, and factors that affect the biomarker such as diet, smoking, and adiposity. Recent studies have evaluated the response of the biomarker to controlled carotenoid interventions, both supplement-based and dietary [e.g., provision of a high-carotenoid fruit and vegetable (F/V)-enriched diet], demonstrating consistent response to intervention. The totality of evidence supports the use of skin carotenoid status as an objective biomarker of F/V intake, although in the cross-sectional setting, diet explains only some of the variation in this biomarker. However, this limitation is also a strength in that skin carotenoids may effectively serve as an integrated biomarker of health, with higher status reflecting greater F/V intake, lack of smoking, and lack of adiposity. Thus, this biomarker holds promise as both a health biomarker and an objective indicator of F/V intake, supporting its further development and utilization for medical and public health purposes.

  15. Evaluation of expert criteria for preoperative magnetic resonance imaging of newly diagnosed breast cancer.

    PubMed

    Behrendt, Carolyn E; Tumyan, Lusine; Gonser, Laura; Shaw, Sara L; Vora, Lalit; Paz, I Benjamin; Ellenhorn, Joshua D I; Yim, John H

    2014-08-01

    Despite 2 randomized trials reporting no reduction in operations or local recurrence at 1 year, preoperative magnetic resonance imaging (MRI) is increasingly used in diagnostic workup of breast cancer. We evaluated 5 utilization criteria recently proposed by experts. Of women (n = 340) newly diagnosed with unilateral breast cancer who underwent bilateral MRI, most (69.4%) met at least 1 criterion before MRI: mammographic density (44.4%), under consideration for partial breast irradiation (PBI) (19.7%), genetic-familial risk (12.9%), invasive lobular carcinoma (11.8%), and multifocal/multicentric disease (10.6%). MRI detected occult malignant lesion or extension of index lesion in 21.2% of index, 3.3% of contralateral, breasts. No expert criterion was associated with MRI-detected malignant lesion, which associated instead with pre-MRI plan of lumpectomy without PBI (48.2% of subjects): Odds Ratio 3.05, 95% CI 1.57-5.91 (p adjusted for multiple hypothesis testing = 0.007, adjusted for index-vs-contralateral breast and covariates). The expert guidelines were not confirmed by clinical evidence.

  16. Applications of nuclear magnetic resonance to nondestructive evaluation of advanced materials

    SciTech Connect

    Lizak, M.J.

    1991-01-01

    Two applications of nuclear magnetic resonance to nondestructive evaluation are presented. The first application is NMR imaging of gases and liquids imbibed into porous ceramic matrix composites. This inspection technique takes advantages of the porosity of the ceramic composite material. A fluorocarbon liquid or gas is infiltrated into the pores of the material, and NMR imaging is performed on the fluorine nuclei. The gases and liquids have more amenable relaxation times for imaging than the ceramic itself, enabling imaging to be performed on commercially available equipment. The ceramic composite restricts the diffusion rate of the gas and dramatically alters the spin relaxation times. These differences provide good contrast mechanisms for the NMR imaging techniques. The second application is to monitoring curing of epoxies. Relaxation times were measured for several curing-epoxy systems. It was found that the transverse relaxation time, T{sub 2}, and the relaxation time of dipolar order, T{sub 1D}, were good indicators of the epoxy cure state. The relaxation times are easy to measure and are relatively insensitive to instrumental settings.

  17. Magnetic resonance enterography for the evaluation of the deep small intestine in Crohn's disease

    PubMed Central

    Takenaka, Kento; Kitazume, Yoshio; Fujii, Toshimitsu; Matsuoka, Katsuyoshi; Kimura, Maiko; Nagaishi, Takashi; Watanabe, Mamoru

    2016-01-01

    For the control of Crohn's disease (CD) a thorough assessment of the small intestine is essential; several modalities may be utilized, with cross-sectional imaging being important. Magnetic resonance (MR) enterography, i.e., MRE is recommended as a modality with the highest accuracy for CD lesions. MRE and MR enteroclysis are the two methods performed following distension of the small intestine. MRE has sensitivity and specificity comparable to computed tomography enterography (CTE); although images obtained using MRE are less clear compared with CTE, MRE does not expose the patient to radiation and is superior for soft-tissue contrast. Furthermore, it can assess not only static but also dynamic and functional imaging and reveals signs of CD, such as abscess, comb sign, fat edema, fistula, lymph node enhancement, less motility, mucosal lesions, stricture, and wall enhancement. Several indices of inflammatory changes and intestinal damage have been proposed for objective evaluation. Recently, diffusion-weighted imaging has been proposed, which does not need bowel preparation and contrast enhancement. Comprehension of the characteristics of MRE and other modalities is important for better management of CD. PMID:27175112

  18. Using Magnetic Resonance Imaging to Evaluate Dendritic Cell-Based Vaccination

    PubMed Central

    Ferguson, Peter M.; Slocombe, Angela; Tilley, Richard D.; Hermans, Ian F.

    2013-01-01

    Cancer immunotherapy with antigen-loaded dendritic cell-based vaccines can induce clinical responses in some patients, but further optimization is required to unlock the full potential of this strategy in the clinic. Optimization is dependent on being able to monitor the cellular events that take place once the dendritic cells have been injected in vivo, and to establish whether antigen-specific immune responses to the tumour have been induced. Here we describe the use of magnetic resonance imaging (MRI) as a simple, non-invasive approach to evaluate vaccine success. By loading the dendritic cells with highly magnetic iron nanoparticles it is possible to assess whether the injected cells drain to the lymph nodes. It is also possible to establish whether an antigen-specific response is initiated by assessing migration of successive rounds of antigen-loaded dendritic cells; in the face of a successfully primed cytotoxic response, the bulk of antigen-loaded cells are eradicated on-route to the node, whereas cells without antigen can reach the node unchecked. It is also possible to verify the induction of a vaccine-induced response by simply monitoring increases in draining lymph node size as a consequence of vaccine-induced lymphocyte trapping, which is an antigen-specific response that becomes more pronounced with repeated vaccination. Overall, these MRI techniques can provide useful early feedback on vaccination strategies, and could also be used in decision making to select responders from non-responders early in therapy. PMID:23734246

  19. Magnetic resonance imaging evaluation of meniscoid superior labrum: normal variant or superior labral tear*

    PubMed Central

    Simão, Marcelo Novelino; Vinson, Emily N.; Spritzer, Charles E.

    2016-01-01

    Objective The objective of this study was to determine the incidence of a "meniscoid" superior labrum. Materials and Methods This was a retrospective analysis of 582 magnetic resonance imaging examinations of shoulders. Of those 582 examinations, 110 were excluded, for a variety of reasons, and the final analysis therefore included 472 cases. Consensus readings were performed by three musculoskeletal radiologists using specific criteria to diagnose meniscoid labra. Results A meniscoid superior labrum was identified in 48 (10.2%) of the 472 cases evaluated. Arthroscopic proof was available in 21 cases (43.8%). In 10 (47.6%) of those 21 cases, the operative report did not include the mention a superior labral tear, thus suggesting the presence of a meniscoid labrum. In only one of those cases were there specific comments about a mobile superior labrum (i.e., meniscoid labrum). In the remaining 11 (52.4%), surgical correlation demonstrated superior labral tears. Conclusion A meniscoid superior labrum is not an infrequent finding. Depending upon assumptions and the requirement of surgical proof, the prevalence of a meniscoid superior labrum in this study was between 2.1% (surgically proven) and 4.8% (projected). However, superior labral tears are just as common and are often confused with meniscoid labra. PMID:27777474

  20. Multidetector Computed Tomography and Magnetic Resonance Imaging Evaluation of Craniovertebral junction Abnormalities

    PubMed Central

    Dhadve, Rajshree U.; Garge, Shaileshkumar S.; Vyas, Pooja D.; Thakker, Nirav R.; Shah, Sonali H.; Jaggi, Sunila T.; Talwar, Inder A.

    2015-01-01

    Background: Craniovertebral junction (CVJ) abnormalities constitute an important group of treatable neurological disorders with diagnostic dilemma. Their precise diagnosis, identification of probable etiology, and pretreatment evaluation significantly affects prognosis and quality of life of patients. Aims: The study was to classify various craniovertebral junction disorders according to their etiology and to define the importance of precise diagnosis for pretreatment evaluation with multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI). Materials and Methods: This is a prospective observational study of 62 patients referred to our department between October 2012 and September 2014. All patients suspected to have a craniovertebral junction disorder were included in the study, from all age groups and both genders. Detailed clinical history was taken. Radiographs of cervical spine were collected if available. All patients were subjected to MDCT and/or MRI. Results: In our study of 62 patients; 39 were males and 23 were females, with male to female ratio of 1.6:1. Most common age group was 2nd -3rd decade (19 patients, 30.64%). Developmental anomalies (33 patients, 53.22%) were the most common etiology group followed by traumatic (10 patients, 16.12%), degenerative (eight patients, 12.90%), infective (four patients, 6.45%), inflammatory and neoplastic (three patients each, 4.8%), and no cause found in one patient. Conclusions: CVJ abnormalities constitute an important group of treatable neurological disorders, especially in certain ethnic groups and are approached with much caution by clinicians. Thus, it is essential that radiologists should be able to make a precise diagnosis of craniovertebral junction abnormalities, classify them into etiological group, and rule out important mimickers on MDCT and/or MRI, as this information ultimately helps determine the management of such abnormalities, prognosis, and quality of life of patients. PMID

  1. Evaluation of an Automated Analysis Tool for Prostate Cancer Prediction Using Multiparametric Magnetic Resonance Imaging

    PubMed Central

    Roethke, Matthias C.; Kuru, Timur H.; Mueller-Wolf, Maya B.; Agterhuis, Erik; Edler, Christopher; Hohenfellner, Markus; Schlemmer, Heinz-Peter; Hadaschik, Boris A.

    2016-01-01

    Objective To evaluate the diagnostic performance of an automated analysis tool for the assessment of prostate cancer based on multiparametric magnetic resonance imaging (mpMRI) of the prostate. Methods A fully automated analysis tool was used for a retrospective analysis of mpMRI sets (T2-weighted, T1-weighted dynamic contrast-enhanced, and diffusion-weighted sequences). The software provided a malignancy prediction value for each image pixel, defined as Malignancy Attention Index (MAI) that can be depicted as a colour map overlay on the original images. The malignancy maps were compared to histopathology derived from a combination of MRI-targeted and systematic transperineal MRI/TRUS-fusion biopsies. Results In total, mpMRI data of 45 patients were evaluated. With a sensitivity of 85.7% (with 95% CI of 65.4–95.0), a specificity of 87.5% (with 95% CI of 69.0–95.7) and a diagnostic accuracy of 86.7% (with 95% CI of 73.8–93.8) for detection of prostate cancer, the automated analysis results corresponded well with the reported diagnostic accuracies by human readers based on the PI-RADS system in the current literature. Conclusion The study revealed comparable diagnostic accuracies for the detection of prostate cancer of a user-independent MAI-based automated analysis tool and PI-RADS-scoring-based human reader analysis of mpMRI. Thus, the analysis tool could serve as a detection support system for less experienced readers. The results of the study also suggest the potential of MAI-based analysis for advanced lesion assessments, such as cancer extent and staging prediction. PMID:27454770

  2. Programmable infusion pump and catheter: evaluation using 3-tesla magnetic resonance imaging.

    PubMed

    Shellock, Frank G; Crivelli, Rocco; Venugopalan, Ramakrishna

    2008-07-01

    Objective.  This study assessed 3-Tesla magnetic resonance imaging (MRI) issues for a programmable infusion pump and associated catheters. Methods.  A programmable infusion pump and associated catheters (MedStream Programmable Infusion Pump, 40 mL; SureStream TI Coil-Reinforced Intraspinal Catheter; SureStream TI Connector; and SureStream Silicone Catheter; Codman and Shurtleff Inc., a Johnson & Johnson Company, Raynham, MA, USA) underwent evaluation for magnetic field interactions (deflection angle and torque), heating (transmit/receive body radiofrequency coil; whole-body averaged specific absorption rate, 3 W/kg for 15 min), functional changes (before and after MRI using eight different MRI conditions), and artifacts (T1-weighted spin-echo and gradient-echo pulse sequences) at 3-Tesla. Results.  The programmable infusion pump and associated catheters exhibited minor magnetic field interactions. Heating was not excessive (≤ 1.9°), especially considering the experimental conditions used for this evaluation (ie, relatively high radiofrequency power/specific absorption rate level and use of a nonperfused phantom). The function of three out of six pumps was temporarily altered by exposures to 3-Tesla MRI conditions. Reset was achieved in each case. Artifacts were relatively large for the pump and minor for the catheter. Conclusions.  The programmable infusion pump and catheters will not pose increased risk to a patient examined using 3-Tesla MRI as long as specific safety guidelines are followed, which includes interrogation of the pump post-MRI to ensure proper settings. Artifacts for the programmable infusion pump may impact the diagnostic use of MRI if the area of interest is in the same area or near the device.

  3. Magnetic resonance imaging and ultrasound evaluation of "healthy" joints in young subjects with severe haemophilia A.

    PubMed

    Di Minno, M N D; Iervolino, S; Soscia, E; Tosetto, A; Coppola, A; Schiavulli, M; Marrone, E; Ruosi, C; Salvatore, M; Di Minno, G

    2013-05-01

    Magnetic resonance imaging (MRI) and ultrasonography (US) are increasingly used in haemophilia A (HA) to detect early joint changes. A total of 40 clinically asymptomatic joints, never involved by bleeding events ["healthy joints" (HJ)], were evaluated by MRI and, in parallel, by US in 20 young subjects with severe HA (22.45 ± 2.72 years old; no history of arthritides, of viral infections or of inhibitors against factor VIII). The same joints were evaluated in 20 matched non-haemophilic (no-HA) subjects (mean age 23.90 ± 2.31 years, P = 0.078 vs. HA subjects). US images were obtained with specific probe positions according to validated procedures. A validated US score and progressive (P-MRI) and additive (A-MRI) MRI scores were employed for data collection and analysis. The US score was higher in HA than in no-HA subjects (3.40 ± 1.72 vs. 0.80 ± 1.10, P < 0.001). Taking into account only moderate/severe alterations, joint effusion was found in 55% of HA and in 5% of no-HA joints (P < 0.001); synovial hypertrophy was found in 20% of HA and in none of the no-HA joints; cartilage erosion was found in 30% of HA and in none of no-HA joints. MRI examinations confirmed these findings and the US score correlated with the A-MRI (r = 0.732, P < 0.001) and with the P-MRI (r = 0.598, P < 0.001) scores. MRI and US data significantly correlated as to effusion (r = 0.819, P = 0.002), synovial hypertrophy (r = 0.633, P = 0.036) and cartilage erosion (r = 0.734, P = 0.010). Despite inherent limitations, joint US examination identified subclinical abnormalities of HJ in young subjects with severe HA.

  4. Evaluation on Micro Cracks in Ceramic Bearing Balls by Using the Floating Resonance of Surface Acoustic Waves

    NASA Astrophysics Data System (ADS)

    Cho, Hideo; Komatsu, Kouichi; Ishikawa, Satoru; Tanimoto, Kiyoshi; Takii, Hirokazu; Yamanaka, Kazushi

    2003-05-01

    Although resonant ultrasound spectroscopy is useful for testing the surface and the inside of objects, the acoustic properties (resonance frequency, mode amplitude ratio, attenuation, etc.) are disturbed by the contact made with supports and transducers. To eliminate this disturbance, we developed the floating resonance (FR) method in which the acoustic properties of bulk and surface acoustic waves (SAWs) are evaluated using laser ultrasound after floating the objects, thus avoiding the contact with the supports and transducers. In this work we applied the FR method to detect artificial flaws on the surface of ceramic bearing balls and a slit as shallow as 50 μm was successfully detected from the attenuation of SAWs after multiple round trips with as many as 20 turns.

  5. Top-down, decoupled control of constitutive parameters in electromagnetic metamaterials with dielectric resonators of internal anisotropy

    NASA Astrophysics Data System (ADS)

    Koo, Sukmo; Mason, Daniel R.; Kim, Yunjung; Park, Namkyoo

    2017-02-01

    A meta-atom platform providing decoupled tuning for the constitutive wave parameters remains as a challenging problem, since the proposition of Pendry. Here we propose an electromagnetic meta-atom design of internal anisotropy (εr ≠ εθ), as a pathway for decoupling of the effective- permittivity εeff and permeability μeff. Deriving effective parameters for anisotropic meta-atom from the first principles, and then subsequent inverse-solving the obtained decoupled solution for a target set of εeff and μeff, we also achieve an analytic, top-down determination for the internal structure of a meta-atom. To realize the anisotropy from isotropic materials, a particle of spatial permittivity modulation in r or θ direction is proposed. As an application example, a matched zero index dielectric meta-atom is demonstrated, to enable the super-funneling of a 50λ-wide flux through a sub-λ slit; unharnessing the flux collection limit dictated by the λ-zone.

  6. Top-down, decoupled control of constitutive parameters in electromagnetic metamaterials with dielectric resonators of internal anisotropy.

    PubMed

    Koo, Sukmo; Mason, Daniel R; Kim, Yunjung; Park, Namkyoo

    2017-02-10

    A meta-atom platform providing decoupled tuning for the constitutive wave parameters remains as a challenging problem, since the proposition of Pendry. Here we propose an electromagnetic meta-atom design of internal anisotropy (εr ≠ εθ), as a pathway for decoupling of the effective- permittivity εeff and permeability μeff. Deriving effective parameters for anisotropic meta-atom from the first principles, and then subsequent inverse-solving the obtained decoupled solution for a target set of εeff and μeff, we also achieve an analytic, top-down determination for the internal structure of a meta-atom. To realize the anisotropy from isotropic materials, a particle of spatial permittivity modulation in r or θ direction is proposed. As an application example, a matched zero index dielectric meta-atom is demonstrated, to enable the super-funneling of a 50λ-wide flux through a sub-λ slit; unharnessing the flux collection limit dictated by the λ-zone.

  7. Top-down, decoupled control of constitutive parameters in electromagnetic metamaterials with dielectric resonators of internal anisotropy

    PubMed Central

    Koo, Sukmo; Mason, Daniel R.; Kim, Yunjung; Park, Namkyoo

    2017-01-01

    A meta-atom platform providing decoupled tuning for the constitutive wave parameters remains as a challenging problem, since the proposition of Pendry. Here we propose an electromagnetic meta-atom design of internal anisotropy (εr ≠ εθ), as a pathway for decoupling of the effective- permittivity εeff and permeability μeff. Deriving effective parameters for anisotropic meta-atom from the first principles, and then subsequent inverse-solving the obtained decoupled solution for a target set of εeff and μeff, we also achieve an analytic, top-down determination for the internal structure of a meta-atom. To realize the anisotropy from isotropic materials, a particle of spatial permittivity modulation in r or θ direction is proposed. As an application example, a matched zero index dielectric meta-atom is demonstrated, to enable the super-funneling of a 50λ-wide flux through a sub-λ slit; unharnessing the flux collection limit dictated by the λ-zone. PMID:28186157

  8. Efficient method for calculating kinetic parameters using T1-weighted dynamic contrast-enhanced magnetic resonance imaging.

    PubMed

    Murase, Kenya

    2004-04-01

    It has become increasingly important to quantitatively estimate tissue physiological parameters such as perfusion, capillary permeability, and the volume of extravascular-extracellular space (EES) using T(1)-weighted dynamic contrast-enhanced MRI (DCE-MRI). A linear equation was derived by integrating the differential equation describing the kinetic behavior of contrast agent (CA) in tissue, from which K(1) (rate constant for the transfer of CA from plasma to EES), k(2) (rate constant for the transfer from EES to plasma), and V(p) (plasma volume) can be easily obtained by the linear least-squares (LLSQ) method. The usefulness of this method was investigated by means of computer simulations, in comparison with the nonlinear least-squares (NLSQ) method. The new method calculated the above parameters faster than the NLSQ method by a factor of approximately 6, and estimated them more accurately than the NLSQ method at a signal-to-noise ratio (SNR) of < approximately 10. This method will be useful for generating functional images of K(1), k(2), and V(p) from DCE-MRI data.

  9. Treatment envelope evaluation in transcranial magnetic resonance-guided focused ultrasound utilizing 3D MR thermometry

    PubMed Central

    2014-01-01

    Background Current clinical targets for transcranial magnetic resonance-guided focused ultrasound (tcMRgFUS) are all located close to the geometric center of the skull convexity, which minimizes challenges related to focusing the ultrasound through the skull bone. Non-central targets will have to be reached to treat a wider variety of neurological disorders and solid tumors. Treatment envelope studies utilizing two-dimensional (2D) magnetic resonance (MR) thermometry have previously been performed to determine the regions in which therapeutic levels of FUS can currently be delivered. Since 2D MR thermometry was used, very limited information about unintended heating in near-field tissue/bone interfaces could be deduced. Methods In this paper, we present a proof-of-concept treatment envelope study with three-dimensional (3D) MR thermometry monitoring of FUS heatings performed in a phantom and a lamb model. While the moderate-sized transducer used was not designed for transcranial geometries, the 3D temperature maps enable monitoring of the entire sonication field of view, including both the focal spot and near-field tissue/bone interfaces, for full characterization of all heating that may occur. 3D MR thermometry is achieved by a combination of k-space subsampling and a previously described temporally constrained reconstruction method. Results We present two different types of treatment envelopes. The first is based only on the focal spot heating—the type that can be derived from 2D MR thermometry. The second type is based on the relative near-field heating and is calculated as the ratio between the focal spot heating and the near-field heating. This utilizes the full 3D MR thermometry data achieved in this study. Conclusions It is shown that 3D MR thermometry can be used to improve the safety assessment in treatment envelope evaluations. Using a non-optimal transducer, it is shown that some regions where therapeutic levels of FUS can be delivered, as suggested by

  10. Evaluation of Coronal Shock Wave Velocities from the II Type Radio Bursts Parameters

    NASA Astrophysics Data System (ADS)

    Galanin, V. V.; Isaeva, E. A.; Kravetz, R. O.

    The work presents the results of research of connection between the coronal shock waves and the parameters of type II (mII) meter-decameter bursts in 25-180 MHz band for 66 solar proton events. The velocities of coronal shock waves for this two cases where determined. In the first case the velocities of the shock waves was evaluated according to the Newkirck model and in the second case - directly from the type II radio burst parameters. The calculated values of shock waves velocity was compared with the same velocity values that is published on NGDC site. The comparative analysis showed that precision of coronal shock waves velocity estimation which gets directly from type II radio bursts parameters was higher than the same one which used the Newkirck model. Research showed that there is exist the sufficiently strong connection between the shock wave velocity and the delay of type II burst intensity maximum on the second harmonica. Correlation coefficient between the studied parameters was equal to ≍ 0.65.

  11. Evaluation of multivariate linear regression and artificial neural networks in prediction of water quality parameters

    PubMed Central

    2014-01-01

    This paper examined the efficiency of multivariate linear regression (MLR) and artificial neural network (ANN) models in prediction of two major water quality parameters in a wastewater treatment plant. Biochemical oxygen demand (BOD) and chemical oxygen demand (COD) as well as indirect indicators of organic matters are representative parameters for sewer water quality. Performance of the ANN models was evaluated using coefficient of correlation (r), root mean square error (RMSE) and bias values. The computed values of BOD and COD by model, ANN method and regression analysis were in close agreement with their respective measured values. Results showed that the ANN performance model was better than the MLR model. Comparative indices of the optimized ANN with input values of temperature (T), pH, total suspended solid (TSS) and total suspended (TS) for prediction of BOD was RMSE = 25.1 mg/L, r = 0.83 and for prediction of COD was RMSE = 49.4 mg/L, r = 0.81. It was found that the ANN model could be employed successfully in estimating the BOD and COD in the inlet of wastewater biochemical treatment plants. Moreover, sensitive examination results showed that pH parameter have more effect on BOD and COD predicting to another parameters. Also, both implemented models have predicted BOD better than COD. PMID:24456676

  12. A tailored multi-frequency EPR approach to accurately determine the magnetic resonance parameters of dynamic nuclear polarization agents: application to AMUPol.

    PubMed

    Gast, P; Mance, D; Zurlo, E; Ivanov, K L; Baldus, M; Huber, M

    2017-02-01

    To understand the dynamic nuclear polarization (DNP) enhancements of biradical polarizing agents, the magnetic resonance parameters need to be known. We describe a tailored EPR approach to accurately determine electron spin-spin coupling parameters using a combination of standard (9 GHz), high (95 GHz) and ultra-high (275 GHz) frequency EPR. Comparing liquid- and frozen-solution continuous-wave EPR spectra provides accurate anisotropic dipolar interaction D and isotropic exchange interaction J parameters of the DNP biradical AMUPol. We found that D was larger by as much as 30% compared to earlier estimates, and that J is 43 MHz, whereas before it was considered to be negligible. With the refined data, quantum mechanical calculations confirm that an increase in dipolar electron-electron couplings leads to higher cross-effect DNP efficiencies. Moreover, the DNP calculations qualitatively reproduce the difference of TOTAPOL and AMUPol DNP efficiencies found experimentally and suggest that AMUPol is particularly effective in improving the DNP efficiency at magnetic fields higher than 500 MHz. The multi-frequency EPR approach will aid in predicting the optimal structures for future DNP agents.

  13. Evaluation of seatback vibration based on ISO 2631-1 (1997) standard method: The influence of vehicle seat structural resonance.

    PubMed

    Ittianuwat, R; Fard, M; Kato, K

    2017-01-01

    Although much research has been done in developing the current ISO 2631-1 (1997) standard method for assessment seat vibration comfort, little consideration has been given to the influence of vehicle seat structural dynamics on comfort assessment. Previous research has shown that there are inconsistencies between standard methods and subjective evaluation of comfort at around vehicle seat twisting resonant frequencies. This study reports the frequency-weighted r.m.s. accelerations in [Formula: see text], [Formula: see text] and [Formula: see text] axes and the total vibration (point vibration total value) at five locations on seatback surface at around vehicle seat twisting resonant frequencies. The results show that the vibration measured at the centre of seatback surface, suggested by current ISO 2631-1 (1997), at around twisting resonant frequencies was the least for all tested vehicle seats. The greatest point vibration total value on the seatback surface varies among vehicle seats. The variations in vibration measured at different locations on seatback surface at around twisting resonant frequencies were sufficiently great that might affect the comfort assessment of vehicle seat.Practitioner Summary: The influence of vehicle seat structural dynamics has not been considered in current ISO 2631-1 (1997). The results of this study show that the vibration measures on seatback surface at around vehicle seat twisting resonant frequency depends on vehicle seats and dominate at the top or the bottom of seatback but not at the centre.

  14. Evaluation of an active magnetic resonance tracking system for interstitial brachytherapy

    PubMed Central

    Wang, Wei; Viswanathan, Akila N.; Damato, Antonio L.; Chen, Yue; Tse, Zion; Pan, Li; Tokuda, Junichi; Seethamraju, Ravi T.; Dumoulin, Charles L.; Schmidt, Ehud J.; Cormack, Robert A.

    2015-01-01

    Purpose: In gynecologic cancers, magnetic resonance (MR) imaging is the modality of choice for visualizing tumors and their surroundings because of superior soft-tissue contrast. Real-time MR guidance of catheter placement in interstitial brachytherapy facilitates target coverage, and would be further improved by providing intraprocedural estimates of dosimetric coverage. A major obstacle to intraprocedural dosimetry is the time needed for catheter trajectory reconstruction. Herein the authors evaluate an active MR tracking (MRTR) system which provides rapid catheter tip localization and trajectory reconstruction. The authors assess the reliability and spatial accuracy of the MRTR system in comparison to standard catheter digitization using magnetic resonance imaging (MRI) and CT. Methods: The MRTR system includes a stylet with microcoils mounted on its shaft, which can be inserted into brachytherapy catheters and tracked by a dedicated MRTR sequence. Catheter tip localization errors of the MRTR system and their dependence on catheter locations and orientation inside the MR scanner were quantified with a water phantom. The distances between the tracked tip positions of the MRTR stylet and the predefined ground-truth tip positions were calculated for measurements performed at seven locations and with nine orientations. To evaluate catheter trajectory reconstruction, fifteen brachytherapy catheters were placed into a gel phantom with an embedded catheter fixation framework, with parallel or crossed paths. The MRTR stylet was then inserted sequentially into each catheter. During the removal of the MRTR stylet from within each catheter, a MRTR measurement was performed at 40 Hz to acquire the instantaneous stylet tip position, resulting in a series of three-dimensional (3D) positions along the catheter’s trajectory. A 3D polynomial curve was fit to the tracked positions for each catheter, and equally spaced dwell points were then generated along the curve. High

  15. Evaluation of an active magnetic resonance tracking system for interstitial brachytherapy

    SciTech Connect

    Wang, Wei; Pan, Li; Tokuda, Junichi; Schmidt, Ehud J.; Seethamraju, Ravi T.; Dumoulin, Charles L.

    2015-12-15

    Purpose: In gynecologic cancers, magnetic resonance (MR) imaging is the modality of choice for visualizing tumors and their surroundings because of superior soft-tissue contrast. Real-time MR guidance of catheter placement in interstitial brachytherapy facilitates target coverage, and would be further improved by providing intraprocedural estimates of dosimetric coverage. A major obstacle to intraprocedural dosimetry is the time needed for catheter trajectory reconstruction. Herein the authors evaluate an active MR tracking (MRTR) system which provides rapid catheter tip localization and trajectory reconstruction. The authors assess the reliability and spatial accuracy of the MRTR system in comparison to standard catheter digitization using magnetic resonance imaging (MRI) and CT. Methods: The MRTR system includes a stylet with microcoils mounted on its shaft, which can be inserted into brachytherapy catheters and tracked by a dedicated MRTR sequence. Catheter tip localization errors of the MRTR system and their dependence on catheter locations and orientation inside the MR scanner were quantified with a water phantom. The distances between the tracked tip positions of the MRTR stylet and the predefined ground-truth tip positions were calculated for measurements performed at seven locations and with nine orientations. To evaluate catheter trajectory reconstruction, fifteen brachytherapy catheters were placed into a gel phantom with an embedded catheter fixation framework, with parallel or crossed paths. The MRTR stylet was then inserted sequentially into each catheter. During the removal of the MRTR stylet from within each catheter, a MRTR measurement was performed at 40 Hz to acquire the instantaneous stylet tip position, resulting in a series of three-dimensional (3D) positions along the catheter’s trajectory. A 3D polynomial curve was fit to the tracked positions for each catheter, and equally spaced dwell points were then generated along the curve. High

  16. Controlling precise magnetic field configuration around electron cyclotron resonance zone for enhancing plasma parameters and beam current.

    PubMed

    Yano, Keisuke; Kurisu, Yosuke; Nozaki, Dai; Kimura, Daiju; Imai, Youta; Kumakura, Sho; Sato, Fuminobu; Kato, Yushi; Iida, Toshiyuki

    2014-02-01

    Multi-charged ion source which has wide operating conditions is required in various application fields. We have constructed tandem type ECR ion source (ECRIS); one of the features of its main stage is an additional coil for controlling magnetic field distribution around the mirror bottom precisely. Here the effect of magnetic field variation caused by the additional coil is experimentally considered in terms of plasma parameters and beam current as the first investigation of the main stage plasma. Furthermore, behavior of magnetic lines of force flowing from the ECR zone is calculated, and is compared with measurement results aiming for better understanding of interrelationship between plasma production and ion beam generation on the ECRIS.

  17. Evaluation of AGNI SFR core neutronics parameters with VESTA and ERANOS

    NASA Astrophysics Data System (ADS)

    Ecrabet, Fabrice; Haeck, Wim; Chaitanya Tadepalli, Sai

    2014-06-01

    This paper presents the calculation of core neutronics parameters for so called AGNI Sodium Fast Reactor (SFR) model performed with ERANOS code and Monte Carlo depletion interface software VESTA. The AGNI core has been developed at IRSN for its own R&D needs, i.e. to test performance of calculation codes for safety assessment of a generation IV SFR project. The ERANOS code is used as reference code for SFR core calculations at IRSN. In this work, VESTA calculations have been performed and compared with corresponding ERANOS results. These calculations have a double purpose: mastering the use of tools for the evaluation of SFR core static neutronics parameters and validate the use of VESTA for SFR cores.

  18. Evaluation of Experimental Parameters in the Accelerated Aging of Closed-Cell Foam Insulation

    SciTech Connect

    Stovall, Therese K; Vanderlan, Michael; Atchley, Jerald Allen

    2012-12-01

    The thermal conductivity of many closed-cell foam insulation products changes over time as production gases diffuse out of the cell matrix and atmospheric gases diffuse into the cells. Thin slicing has been shown to be an effective means of accelerating this process in such a way as to produce meaningful results. Efforts to produce a more prescriptive version of the ASTM C1303 standard test method led to the ruggedness test described here. This test program included the aging of full size insulation specimens for time periods of five years for direct comparison to the predicted results. Experimental parameters under investigation include: slice thickness, slice origin (at the surface or from the core of the slab), thin slice stack composition, product facings, original product thickness, product density, and product type. The test protocol has been completed and this report provides a detailed evaluation of the impact of the test parameters on the accuracy of the 5-year thermal conductivity prediction.

  19. Evaluation of the Ecochemical Status of the Danube in Serbia in Terms of Water Quality Parameters

    PubMed Central

    Takić, Ljiljana; Mladenović-Ranisavljević, Ivana; Vuković, Milovan; Mladenović, Ilija

    2012-01-01

    The Danube is an international river passing partly through Serbia. The protection of the environment and sustainable use of water resources is a primary task that implies constant monitoring of the quality status and evaluation of ecochemical status of the water in the Danube basin. The investigation includes calculation of all-inclusive water quality by the Serbian water quality index (SWQI) method and an evaluation of eco-chemical status of the Danube water in terms of water quality parameters from the entry to the exit point along its course through Serbia in the year of 2009. The results show that the overall quality of the Danube water on the territory of Serbia corresponds to the descriptive indicator of “very good” water. According to the Council Directive75/440/EEC, the evaluation of the ecostatus, with slight deviation of individual parameters at Pančevo, corresponds to A1 category of the surface water quality intended for the abstraction of drinking water supplies in member states. PMID:22645471

  20. On the evaluation of Pierce parameters C and Q in a traveling wave tube

    NASA Astrophysics Data System (ADS)

    Simon, D. H.; Wong, P.; Chernin, D.; Lau, Y. Y.; Hoff, B.; Zhang, P.; Dong, C. F.; Gilgenbach, R. M.

    2017-03-01

    A study of an exactly solvable model of a traveling wave tube (TWT) shows that Pierce gain parameter C and space charge parameter Q generally depend on wavenumber k in addition to frequency ω. The choice of k at which C and Q are evaluated may strongly affect their values and, consequently, the values of the small signal gain obtained from 3- and 4-wave Pierce theory. In order to illustrate this effect, we calculate the spatial amplification rate, ki, from the exact dispersion relation for a dielectric TWT model which is exactly solvable. We compare this exact value of ki with approximate values obtained from Pierce's classical 3-wave and 4-wave dispersion relations, obtained by making various assumptions on k in the evaluation of C and Q. We find that the various ways to approximate C and Q will have a significant influence on the numerical values of ki. For our dielectric TWT example, Pierce's 4-wave TWT dispersion relation generally yields the most accurate values of ki if Q is evaluated for k = ω/v0, where v0 is the beam velocity, and if the complete frequency and wavelength dependence of C is retained. Pierce's 3-wave theory also yields accurate values of ki using a different form of Q from the 4-wave theory. The implications of this result for TWT design are explored.

  1. Evaluation of breast cancer chemotherapy efficacy with multifractal spectrum analysis of magnetic resonance image.

    PubMed

    Li, Li; Hu, Wen-yong; Liu, Li-zhi; Pang, Ya-chun; Shao, Yuan-zhi

    2014-01-01

    Multifractal spectrum analysis of dynamic contrast enhanced (DCE) breast MR images was used to establish a new quantitative analysis method for solid tumor blood perfusion and to explore its applicability in evaluating efficacy of breast cancer chemotherapy. Five randomly selected patients suffering from newly diagnosed malignant breast nodule lesions were enrolled in this study, and four of them were treated with neoadjuvant chemotherapy. Their DCE breast MR images were collected before and after treatment. Chemotherapeutic efficacy was analyzed using international response evaluation criteria for solid tumors (RECIST). Sandbox method for statistical number density was employed to measure and calculate multifractal spectra of DCE breast MR images with spatiotemporal characteristics. Multifractal spectral data of malignant lesions before and after chemotherapy were compared. Multifractal spectra of malignant lesions show an asymmetric bell-shape. Chemotherapy efficacy was assessed to be partial remission (PR) for three patients and their multifractal spectral width significantly increased after chemotherapy while to be stable disease (SD) for other patient and of her changed slightly. Multifractal spectral width correlates with blood-supply condition of tumor lesion before and after chemotherapy, providing a potential suitable characteristic parameter for evaluating chemotherapeutic efficacy quantitatively.

  2. Evaluation of partial widths and branching ratios from resonance wave functions

    SciTech Connect

    Goldzak, Tamar; Gilary, Ido; Moiseyev, Nimrod

    2010-11-15

    A quantum system in a given resonance state has different open channels for decay. Partial widths are the decay rates of the resonance (metastable) state into the different open channels. Here we present a rigorous derivation of the partial widths from the solution of a time-dependent Schroedinger equation with outgoing boundary conditions. We show that the sum of the partial widths obtained from the resonance wave function is equal to the total width. The difference with respect to previous studies on partial widths and branching ratios is discussed.

  3. Quantifiable Imaging Biomarkers for Evaluation of the Posterior Cruciate Ligament Using 3-T Magnetic Resonance Imaging

    PubMed Central

    Wilson, Katharine J.; Surowiec, Rachel K.; Ho, Charles P.; Devitt, Brian M.; Fripp, Jurgen; Smith, W. Sean; Spiegl, Ulrich J.; Dornan, Grant J.; LaPrade, Robert F.

    2016-01-01

    Background: Quantitative magnetic resonance imaging (MRI) techniques, such as T2 and T2 star (T2*) mapping, have been used to evaluate ligamentous tissue in vitro and to identify significant changes in structural integrity of a healing ligament. These studies lay the foundation for a clinical study that uses quantitative mapping to evaluate ligaments in vivo, particularly the posterior cruciate ligament (PCL). To establish quantitative mapping as a clinical tool for identifying and evaluating chronic or acute PCL injuries, T2 and T2* values first must be determined for an asymptomatic population. Purpose: To quantify T2 and T2* mapping properties, including texture variables (entropy, variance, contrast, homogeneity), of the PCL in an asymptomatic population. It was hypothesized that biomarker values would be consistent throughout the ligament, as measured across 3 clinically relevant subregions (proximal, middle, and distal thirds) in the asymptomatic cohort. Study Design: Cross-sectional study; Level of evidence, 4. Methods: Unilateral knee MRI scans were acquired for 25 asymptomatic subjects with a 3.0-T MRI system using T2 and T2* mapping sequences in the sagittal plane. The PCL was manually segmented and divided into thirds (proximal, middle, and distal). Summary statistics for T2 and T2* values were calculated. Intra- and interrater reliability was assessed across 3 raters to 2 time points. Results: The asymptomatic PCL cohort had mean T2 values of 36.7, 29.2, and 29.6 ms in the distal, middle, and proximal regions, respectively. The distal PCL exhibited significantly higher mean, variance, and contrast and lower homogeneity of T2 values than the middle and proximal subregions (P < .05). T2* results exhibited substantial positive skew and were therefore presented as median and quartile (Q) values. Median T2* values were 7.3 ms (Q1-Q3, 6.8-8.9 ms), 7.3 ms (Q1-Q3, 7.0-8.5 ms), and 7.3 ms (Q1-Q3, 6.4-8.2 ms) in the distal, middle, and proximal subregions

  4. Benchmark Testing of a New 56Fe Evaluation for Criticality Safety Applications

    SciTech Connect

    Leal, Luiz C; Ivanov, E.

    2015-01-01

    The SAMMY code was used to evaluate resonance parameters of the 56Fe cross section in the resolved resonance energy range of 0–2 MeV using transmission data, capture, elastic, inelastic, and double differential elastic cross sections. The resonance analysis was performed with the code SAMMY that fits R-matrix resonance parameters using the generalized least-squares technique (Bayes’ theory). The evaluation yielded a set of resonance parameters that reproduced the experimental data very well, along with a resonance parameter covariance matrix for data uncertainty calculations. Benchmark tests were conducted to assess the evaluation performance in benchmark calculations.

  5. Experimental evaluation of the effects of pravastatin on electrophysiological parameters of rat skeletal muscle.

    PubMed

    Pierno, S; De Luca, A; Tricarico, D; Ferrannini, E; Conte, T; D'Alò, G; Camerino, D C

    1992-11-01

    The effects of daily chronic treatment for 6 months with pravastatin was evaluated on the performance of the skeletal muscle system of different rat groups. At all doses (0.1 mg/kg-20 mg/kg) the righting reflex and the electromyographic signals observed in vivo did not show any abnormality. At the end of the treatment the Extensor digitorum longus muscles were dissected from treated and control rats and their passive and active electrical parameters were analyzed in vitro by standard microelectrodes technique. Pravastatin did not modify the chloride conductance nor the excitability characteristics of the fibers. Chronic treatment with pravastatin does not produce any alteration of skeletal muscle function.

  6. Evaluation of the Parameters Affecting the Cohesion of Fine Grained Soil

    NASA Astrophysics Data System (ADS)

    Vondráčková, Terezie; Kmec, Ján; Čejka, Jiří; Bartuška, Ladislav; Stopka, Ondrej

    2016-10-01

    Cohesion of the soils is one of the most important parameters which soil is evaluated in terms of its suitability for building foundations. Safety of construction is in fact dependent on the strength of soil, respectively shear strength. Fine-grained soil represents very specific group, in which is distinguished an effective and total cohesion of soils. The water in the soil thus drastically affects its cohesion contrary to gravel and sandy soils. The publication compares the tabular values of the effective and total cohesion and define the influence of water, grain size and consistency of her behaviour.

  7. Incorporating doubly resonant W ± data in a global fit of SMEFT parameters to lift flat directions

    NASA Astrophysics Data System (ADS)

    Berthier, Laure; Bjørn, Mikkel; Trott, Michael

    2016-09-01

    We calculate the double pole contribution to two to four fermion scattering through W ± currents at tree level in the Standard Model Effective Field Theory (SMEFT). We assume all fermions to be massless, U(3)5 flavour and CP symmetry. Using this result, we update the global constraint picture on SMEFT parameters including LEPII data on these charged current processes, and also modifications to our fit procedure motivated by a companion paper focused on W ± mass extractions. The fit reported is now to 177 observables and emphasises the need for a consistent inclusion of theoretical errors, and a consistent treatment of observables. Including charged current data lifts the two-fold degeneracy previously encountered in LEP (and lower energy) data, and allows us to set simultaneous constraints on 20 of 53 Wilson coefficients in the SMEFT, consistent with our assumptions. This allows the model independent inclusion of LEP data in SMEFT studies at LHC, which are projected into the SMEFT in a consistent fashion. We show how stronger constraints can be obtained by using some combinations of Wilson coefficients, when making assumptions on the UV completion of the Standard Model, or in an inconsistent analysis. We explain why strong bounds at the per-mille or sub-per-mille level on some combinations of Wilson coefficients in the Effective Lagrangian can be artificially enhanced in fits of this form in detail. This explains some of the different claims present in the literature.

  8. Modifications in Dynamic Contrast-Enhanced Magnetic Resonance Imaging Parameters After α-Particle-Emitting {sup 227}Th-trastuzumab Therapy of HER2-Expressing Ovarian Cancer Xenografts

    SciTech Connect

    Heyerdahl, Helen; Røe, Kathrine; Brevik, Ellen Mengshoel; Dahle, Jostein

    2013-09-01

    Purpose: The purpose of this study was to investigate the effect of α-particle-emitting {sup 227}Th-trastuzumab radioimmunotherapy on tumor vasculature to increase the knowledge about the mechanisms of action of {sup 227}Th-trastuzumab. Methods and Materials: Human HER2-expressing SKOV-3 ovarian cancer xenografts were grown bilaterally in athymic nude mice. Mice with tumor volumes 253 ± 36 mm{sup 3} (mean ± SEM) were treated with a single injection of either {sup 227}Th-trastuzumab at a dose of 1000 kBq/kg body weight (treated group, n=14 tumors) or 0.9% NaCl (control group, n=10 tumors). Dynamic T1-weighted contrast-enhanced magnetic resonance imaging (DCEMRI) was used to study the effect of {sup 227}Th-trastuzumab on tumor vasculature. DCEMRI was performed before treatment and 1, 2, and 3 weeks after therapy. Tumor contrast-enhancement curves were extracted voxel by voxel and fitted to the Brix pharmacokinetic model. Pharmacokinetic parameters for the tumors that underwent radioimmunotherapy were compared with the corresponding parameters of control tumors. Results: Significant increases of k{sub ep}, the rate constant of diffusion from the extravascular extracellular space to the plasma (P<.05), and k{sub el,} the rate of clearance of contrast agent from the plasma (P<.01), were seen in the radioimmunotherapy group 2 and 3 weeks after injection, compared with the control group. The product of k{sub ep} and the amplitude parameter A, associated with increased vessel permeability and perfusion, was also significantly increased in the radioimmunotherapy group 2 and 3 weeks after injection (P<.01). Conclusions: Pharmacokinetic modeling of MRI contrast-enhancement curves evidenced significant alterations in parameters associated with increased tumor vessel permeability and tumor perfusion after {sup 227}Th-trastuzumab treatment of HER2-expressing ovarian cancer xenografts.

  9. An evaluation of neural networks for identification of system parameters in reactor noise signals

    SciTech Connect

    Miller, L.F.

    1991-12-31

    Several backpropagation neural networks for identifying fundamental mode eigenvalues were evaluated. The networks were trained and tested on analytical data and on results from other numerical methods. They were then used to predict first mode break frequencies for noise data from several sources. These predictions were, in turn, compared with analytical values and with results from alternative methods. Comparisons of results for some data sets suggest that the accuracy of predictions from neural networks are essentially equivalent to results from conventional methods while other evaluations indicate that either method may be superior. Experience gained from these numerical experiments provide insight for improving the performance of neural networks relative to other methods for identifying parameters associated with experimental data. Neural networks may also be used in support of conventional algorithms by providing starting points for nonlinear minimization algorithms.

  10. Magnetic Resonance Image Evaluation of Temporomandibular Joint Osteophytes: Influence of Clinical Factors and Artrogenics Changes.

    PubMed

    Grossmann, Eduardo; Remedi, Marcelo Pereira; Ferreira, Luciano Ambrosio; Carvalho, Antonio Carlos Pires

    2016-03-01

    This research aims to examine the presence of osteophyte in patients with arthrogenic temporomandibular disorders through magnetic resonance imaging (MRI); to investigate the influence of sex and clinical symptoms in its prevalence; and the position of the osteophytes in the condyle. The study was based on 100 MRI and on reports of patients, which corresponded to the evaluation of 200 joints. Patients of both sexes were aged from 18 to 82 years (average = 49.48) and were subjected to the aforementioned examination from January 2006 to March 2009. The assessment considered the type of disc displacement, the presence of effusion, bone marrow edema, condyle changes, joint noise and pain. The MRI machine used was the GE Signa HDX (General Electric, Milwaukee, WI), with T1 and T2-weighted, 1.5 T magnetic field, sagittal oblique (mouth closed, mouth open) and coronal (mouth closed) imaging, with spherical surface coil and an asymmetric matrix. All images were interpreted by an experienced radiologist. A total of 28% (n = 56) of the temporomandibular joints showed osteophytes on the anterior surface of the mandible. No relationship was found between sex and osteophytes. The authors found a statistically significant difference between osteophytes and disc displacement without reduction (P < 0.001). The presence of osteophytes suggested a possible cause and effect relationship between osteoarthritis and disc displacement without reduction; the osteophyte was always located in the anterior surface of condyle, regardless of the sex variable; no significant difference was found between osteophytes and the main complaints of the patient.

  11. Further Evaluation of the Neutron Resonance Transmission Analysis (NRTA) Technique for Assaying Plutonium in Spent Fuel

    SciTech Connect

    J. W. Sterbentz; D. L. Chichester

    2011-09-01

    This is an end-of-year report (Fiscal Year (FY) 2011) for the second year of effort on a project funded by the National Nuclear Security Administration's Office of Nuclear Safeguards (NA-241). The goal of this project is to investigate the feasibility of using Neutron Resonance Transmission Analysis (NRTA) to assay plutonium in commercial light-water-reactor spent fuel. This project is part of a larger research effort within the Next-Generation Safeguards Initiative (NGSI) to evaluate methods for assaying plutonium in spent fuel, the Plutonium Assay Challenge. The second-year goals for this project included: (1) assessing the neutron source strength needed for the NRTA technique, (2) estimating count times, (3) assessing the effect of temperature on the transmitted signal, (4) estimating plutonium content in a spent fuel assembly, (5) providing a preliminary assessment of the neutron detectors, and (6) documenting this work in an end of the year report (this report). Research teams at Los Alamos National Laboratory (LANL), Lawrence Berkeley National Laboratory (LBNL), Pacific Northwest National Laboratory (PNNL), and at several universities are also working to investigate plutonium assay methods for spent-fuel safeguards. While the NRTA technique is well proven in the scientific literature for assaying individual spent fuel pins, it is a newcomer to the current NGSI efforts studying Pu assay method techniques having just started in March 2010; several analytical techniques have been under investigation within this program for two to three years or more. This report summarizes work performed over a nine month period from January-September 2011 and is to be considered a follow-on or add-on report to our previous published summary report from December 2010 (INL/EXT-10-20620).

  12. Evaluation of Angiographic and Technical Aspects of Carotid Stenting with Diffusion-Weighted Magnetic Resonance Imaging

    SciTech Connect

    Blasel, Stella Hattingen, Elke; Berkefeld, Joachim; Kurre, Wiebke; Morawe, Gerald; Zanella, Friedhelm; Rochemont, Richard Du Mesnil de

    2009-07-15

    The detection of clinically silent ischemic lesions on postprocedural diffusion-weighted magnetic resonance images has become a preferred method for the description of embolic risks. The purpose of this single-center study was to evaluate whether diffusion-weighted imaging (DWI) could determine material related or technical risk factors of filter-protected carotid stenting. Eighty-four patients with symptomatic severe ({>=}60%) carotid artery stenoses received filter-protected carotid stenting. Standard DWI (b = 1000) was performed within 48 h before and after carotid stenting. The occurrence and load of new postinterventional DWI lesions were assessed. Multivariate analysis was performed to determine risk factors associated with DWI lesions, with emphasis on technical factors such as use of different access devices (guiding catheter method vs. long carotid sheath method), type of stent (open-cell nitinol stent vs. closed-cell Wallstent), and protective device (filters with 80-{mu}m vs. 110-120-{mu}m pore size). Markers for generalized atherosclerosis and for degree and site of stenosis were assessed to allow comparison of adequate risk profiles. Access, protective device, and stent type were not significantly associated with new embolic DWI lesions when we compared patients with equivalent risk profiles (long carotid sheath method 48% [11 of 23] vs. guiding catheter method 44% [27 of 61], Wallstent 47% [15 of 32] vs. nitinol stent 44% [23 of 52], and small pore size filter 61% [11 of 18] vs. large pore size filter 41% [27 of 66]). Single-center DWI studies with a moderate number of cases are inadequate for proper assessment of the embolic risk of technical- or material-related risk factors in carotid stenting. Larger multicenter studies with more cases are needed.

  13. Evaluation of Oxidative Stress Parameters and Urinary Deoxypyridinoline Levels in Geriatric Patients with Osteoporosis

    PubMed Central

    Demir, Mehmet; Ulas, Turgay; Tutoglu, Ahmet; Boyaci, Ahmet; Karakas, Emel Yigit; Sezen, Hatice; Ustunel, Murat; Bilinc, Hasan; Gencer, Mehmet; Buyukhatipoglu, Hakan

    2014-01-01

    [Purpose] To evaluate the oxidative stress parameters and urinary deoxypyridinoline levels in geriatric patients with osteoporosis. [Subjects and Methods] Eighty geriatric patients aged over 65 years were recruited. Patients were divided into two groups: Group 1 (n=40) consisted of patients with osteoporosis, and Group 2 (n=40) consisted of patients without osteoporosis. Bone mineral density measurements were performed for all patients using DEXA. Oxidative stress parameters were analyzed in blood samples, and deoxypyridinoline levels were analyzed in 24-hour urinary samples. [Results] Compared to Group 2, the total antioxidant status and oxidative stress index levels of Group 1 were not significantly different; however, total oxidant status and 24-hour urinary deoxypyridinoline levels were significantly higher. Pearson correlation coefficients indicated that OSI and urinary deoxypyridinoline levels were not correlated with any biochemical parameters. ROC-curve analysis revealed that urinary deoxypyridinoline levels over 30.80 mg/ml predicted osteoporosis with 67% sensitivity and 68% specificity (area under the curve = 0.734; %95 CI: 0.624–0.844). [Conclusion] Our results indicate that oxidative stress would play a role in the pathogenesis of osteoporosis, and that urinary deoxypyridinoline levels may be a useful screening test for osteoporosis. PMID:25276024

  14. Evaluation of Anaerobic Biofilm Reactor Kinetic Parameters Using Ant Colony Optimization.

    PubMed

    Satya, Eswari Jujjavarapu; Venkateswarlu, Chimmiri

    2013-09-01

    Fixed bed reactors with naturally attached biofilms are increasingly used for anaerobic treatment of industry wastewaters due their effective treatment performance. The complex nature of biological reactions in biofilm processes often poses difficulty in analyzing them experimentally, and mathematical models could be very useful for their design and analysis. However, effective application of biofilm reactor models to practical problems suffers due to the lack of knowledge of accurate kinetic models and uncertainty in model parameters. In this work, an inverse modeling approach based on ant colony optimization is proposed and applied to estimate the kinetic and film thickness model parameters of wastewater treatment process in an anaerobic fixed bed biofilm reactor. Experimental data of pharmaceutical industry wastewater treatment process are used to determine the model parameters as a consequence of the solution of the rigorous mathematical models of the process. Results were evaluated for different modeling configurations derived from the combination of mathematical models, kinetic expressions, and optimization algorithms. Analysis of results showed that the two-dimensional mathematical model with Haldane kinetics better represents the pharmaceutical wastewater treatment in the biofilm reactor. The mathematical and kinetic modeling of this work forms a useful basis for the design and optimization of industry wastewater treating biofilm reactors.

  15. Evaluation of voice pathology based on the estimation of vocal fold biomechanical parameters.

    PubMed

    Gómez-Vilda, P; Fernández-Baillo, R; Nieto, A; Díaz, F; Fernández-Camacho, F J; Rodellar, V; Alvarez, A; Martínez, R

    2007-07-01

    Voice disorders are a source of increasing concern as normal voice quality is a social demand for at least one third of the population in developed countries in cases where voice is an essential resource in professional exercise. In addition, the growing exposure to certain pathogenic factors such as smoking, alcohol abuse, air pollution, and acoustic contamination, and other problems such as gastro-esopharyngeal reflux or allergy as well as aging, aggravate voice disorders. Voice pathologies justify the assignment of larger resources to prevention policies, early detection, and less aggressive treatments. Traditional pathology detection relies on perceptive evaluation methods (GRABS), acoustic analysis, and visual inspection (indirect laryngoscopy, and modern fibro-endo-stroboscopy). This article describes a method for voice pathology detection based on the noninvasive estimation of vocal cord biomechanical parameters derived from voice using specific signal processing methods. Preliminary results using records from patients showing four frequent causes of voice pathology (nodules, polyps, chronic laryngitis, and Reinke's edema) are given. The results show that the alteration (distortion, unbalance, or deviation) of cord biomechanical parameters may serve as an indicator of pathology. Statistical methods based on hierarchical clustering and principal component analysis reveal that combining biomechanical estimates with classic perturbation parameters increases the accuracy of acoustic analysis, improving the detection of voice pathology. This research could open new possibilities for noninvasive screening of vocal fold pathologies and could be used in the implantation of e-health voice care services.

  16. A possible parameter for gait clinimetric evaluation in Parkinson’s disease patients

    NASA Astrophysics Data System (ADS)

    Lescano, C. N.; Rodrigo, S. E.; Christian, D. A.

    2016-04-01

    The strength and usefulness of a rating scale for describing disease evolution relies on the accurate determination of variations representing clinically relevant changes. In this sense, the habitually used Hoehn-Yahr (HY) Scale for Parkinson Disease (PD) in its modified version distinguishes between the 2 and 2.5 stages to explain if the bilateral involvement is or is not accompanied by body balance impairment. Nevertheless, this scaling does not allow for differentiating the symptoms and signs associated with each stage accurately. Considering this difference, this work aims at analyzing some gait parameters-stance and swing phase times and magnitude of the vertical component of ground reaction force during the gait cycle-of PD patients classified as HY=2 and HY=2.5 in contrast with healthy subjects (HY=0), with the purpose of assessing whether there is a statistically significant difference among all these HY categories. For all gait parameters evaluated, the results indicated significant differences between HY=0 and HY=2.5. However, only the magnitude of the vertical component of ground reaction force presented relevant differences between HY=2 and 2.5. As expected, therefore, these results show the potential of such parameter to clinimetrically identify the level of gait impairment/disability in PD patients on the Hoehn-Yahr Scale.

  17. An evaluation of earthquake hazard parameters in the Iranian Plateau based on the Gumbel III distribution

    NASA Astrophysics Data System (ADS)

    Mohammadi, Hiwa; Bayrak, Yusuf

    2016-04-01

    The Gumbel's third asymptotic distribution (GIII) of the extreme value method is employed to evaluate the earthquake hazard parameters in the Iranian Plateau. This research quantifies spatial mapping of earthquake hazard parameters like annual and 100-year mode beside their 90 % probability of not being exceeded (NBE) in the Iranian Plateau. Therefore, we used a homogeneous and complete earthquake catalogue during the period 1900-2013 with magnitude M w ≥ 4.0, and the Iranian Plateau is separated into equal area mesh of 1° late × 1° long. The estimated result of annual mode with 90 % probability of NBE is expected to exceed the values of M w 6.0 in the Eastern part of Makran, most parts of Central and East Iran, Kopeh Dagh, Alborz, Azerbaijan, and SE Zagros. The 100-year mode with 90 % probability of NBE is expected to overpass the value of M w 7.0 in the Eastern part of Makran, Central and East Iran, Alborz, Kopeh Dagh, and Azerbaijan. The spatial distribution of 100-year mode with 90 % probability of NBE uncovers the high values of earthquake hazard parameters which are frequently connected with the main tectonic regimes of the studied area. It appears that there is a close communication among the seismicity and the tectonics of the region.

  18. Information Theory Approach to Evaluate the Geomagnetic and Ionospheric Response to Solar Wind Parameters

    NASA Astrophysics Data System (ADS)

    Seemala, G. K.; R, S.; Bhaskara, V.; Ramesh, D. S.

    2014-12-01

    The importance of space weather and understanding onset o geomagnetic storms is increasing day by day as the space missions increase. It is known from the ground-based and space-borne observations that a geomagnetic storm is a temporary disturbance of earth's magnetosphere caused by a solar wind and/or solar eruptions. Geomagnetic storms are more disruptive now than in the past because of our greater dependence on technical systems that can be affected by electric currents and energetic particles high in the Earth's magnetosphere. It is known that number of phenomena occurs during the space weather events; and there are many un-solved questions like solar wind coupling with magnetosphere and ionosphere, relationship between geomagnetic storms & sub-storms etc. To evaluate contribution of various interplanetary parameters that have major role in the geomagnetic storm/geomagnetic variations, the information theory approach is used. In information theory, the measure of uncertainty or randomness of a signal can be quantified by using Shannon entropy or entropy for short. And Transfer entropy is capable of quantifying the directional flow of information between two signals. Thus the Transfer entropy is capable of distinguishing effectively driving and responding signals. In this study, we use Transfer entropy function on Solar wind parameters and ground magnetic data to derive the drivers and relations between them, and also study their contributed effect on ionospheric TEC. In this presentation, we will evaluate and present the results obtained, and discuss about the driving forces on the geomagnetic field disturbances.

  19. Evaluation of demographic parameters of native rodent populations and implications for control

    PubMed Central

    French, Norman R.

    1975-01-01

    The ecology of the multimammate mouse ,Mastomys natalensis, is reviewed and approximations are derived for the parameters governing population growth. By means of computer simulation, the relative importance of the timing of reproduction, the age class distribution or age structure of the population, the competition between Mastomys and Rattus, and the interaction with a predator are evaluated. Although each of these demographic or ecological factors modifies the fate of the Mastomys population, the greatest single impact results from a reproductive season that is divided into two parts rather than a single continuous reproductive season. Division into two parts, correlated with a similar distribution of rainfall, allows time for maturing of the young born early in the season and for production of young by them, thus adding to the momentum of population increase. The interaction of density-dependent factors controlling population growth, competition with another rodent, or predation by a Viverrid predator, may increase the growth rate of the Mastomys population or may depress population growth rate, even to the point of extinction. These simulation studies demonstrate the necessity for critical evaluation of the demographic parameters and ecological characteristics of a particular Mastomys population before an effective control programme can be designed. They also demonstrate, however, that if the programme is based upon sound ecological theory control can be effected. PMID:1085223

  20. Evaluation of Toxicity Effects of Asafetida on Biochemical, Hematological, and Histological Parameters in Male Wistar Rats

    PubMed Central

    Bagheri, Seyyed Majid; Yadegari, Maryam; Mirjalily, Aghdas; Rezvani, Mohammd Ebrahim

    2015-01-01

    Objectives: Asafetida is traditionally used in folklore medicine for the treatment of various ailments. To validate its use in traditional medicine, it is important to evaluate its toxicity in the animal system. Therefore, this study aimed to evaluate the toxicological effects of asafetida in Wistar albino rats. Materials and Methods: Acute toxicity tests were conducted by the oral administration of 250, 500, and 1,000 mg/kg body weight of the animal. In chronic study, animals were administered with various doses of asafetida (25, 50, 100, and 200 mg/kg body weight) for a period of 6 weeks. At end of experiment, the effects of asafetida on hematological, renal, and hepatic markers and histological parameters were analyzed. Results: In acute toxicity study, no mortality was seen up to 72 h of the administration of asafetida. No signs of neurological and behavioral changes were noticed within 24 h. In the chronic study, the asafetida intake has changed the hematological parameters such as red blood cell (RBC), white blood cell (WBC), hematocrit (HCT), and platelets. Aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) were significantly increased in treated animals. The plasma level of urea and creatinine were not altered by the administration of asafetida throughout the study. Histopathology study indicates hepatotoxicity, but no signs of prominent pathological changes in kidney. Conclusions: Asafetida did not show any acute toxicity, but chronic administration could have undesirable effects on hepatocytes and hematological factors. PMID:26862262

  1. Markers/parameters for the evaluation of natural resistance status of small ruminants against gastrointestinal nematodes.

    PubMed

    Saddiqi, H A; Sarwar, M; Iqbal, Z; Nisa, M; Shahzad, M A

    2012-06-01

    The high prevalence of anthelmintic-resistant gastrointestinal nematodes (GINs) throughout the world has led to the need for alternative worm control strategies. One of the possible substitutes to reduce the problems of drug resistance and residue is the evaluation/breeding of small ruminants for greater resistance to the GINs (organically produced), which in turn would be a helpful tool to predict the performance of an animal. At present, the existing diversity in the genetic potential to resist/tolerate GINs infection both within and between breeds has been validated. Successful selection of animals to define the genotype and identified resistance is related to the employed markers. A number of phenotypic traits such as faecal egg count (FEC), worm burden, serum antibodies, peripheral eosinophilia, packed cell volume, live weight, serum protein and albumin concentrations have been used for this purpose both in natural and artificial infections. Relatively resistant/tolerant animals have also been found to have mastocytosis, globule leucocytes, high levels of histamine and immunoglobulin (Ig) A and IgE concentrations. Of these traits, the principal and most practical measurement used to assess resistance status in animals undergoing similar parasite challenges is FEC. FEC has a positive/negative correlation with other biochemical, cellular and immunological parameters; however, the reliability of individual trial is often questioned and valuable information regarding the genetic makeup can be obtained from pooled data of a large number of trials and parameters. This paper covers all the aspects reported in the literature on various parameters considered to evaluate the resistance status of a range of small ruminant breeds.

  2. Economic analysis of Royalactin production under uncertainty: Evaluating the effect of parameter optimization.

    PubMed

    Torres-Acosta, Mario A; Aguilar-Yañez, Jose M; Rito-Palomares, Marco; Titchener-Hooker, Nigel J

    2015-01-01

    Royalactin is a protein with several different potential uses in humans. Research, in insects and in mammalian cells, has shown that it can accelerate cell division and prevent apoptosis. The method of action is through the use of the epidermal growth factor receptor, which is present in humans. Potential use in humans could be to lower cholesterolemic levels in blood, and to elicit similar effects to those seen in bees, e.g., increased lifespan. Mass production of Royalactin has not been accomplished, though a recent article presented a Pichia pastoris fermentation and recovery by aqueous two-phase systems at laboratory scale as a possible basis for production. Economic modelling is a useful tool with which compare possible outcomes for the production of such a molecule and in particular, to locate areas where additional research is needed and optimization may be required. This study uses the BioSolve software to perform an economic analysis on the scale-up of the putative process for Royalactin. The key parameters affecting the cost of production were located via a sensitivity analysis and then evaluated by Monte Carlo analysis. Results show that if titer is not optimized the strategy to maintain a low cost of goods is process oriented. After optimization of this parameter the strategy changes to a product-oriented and the target output becomes the critical parameter determining the cost of goods. This study serves to provide a framework for the evaluation of strategies for future production of Royalactin, by analyzing the factors that influence its cost of manufacture.

  3. Fiber-optic sensors for monitoring patient physiological parameters: a review of applicable technologies and relevance to use during magnetic resonance imaging procedures.

    PubMed

    Dziuda, Łukasz

    2015-01-01

    The issues involved with recording vital functions in the magnetic resonance imaging (MRI) environment using fiber-optic sensors are considered in this paper. Basic physiological parameters, such as respiration and heart rate, are fundamental for predicting the risk of anxiety, panic, and claustrophobic episodes in patients undergoing MRI examinations. Electronic transducers are generally hazardous to the patient and are prone to erroneous operation in heavily electromagnetically penetrated MRI environments; however, nonmetallic fiber-optic sensors are inherently immune to electromagnetic effects and will be crucial for acquiring the above-mentioned physiological parameters. Forty-seven MRI-tested or potentially MRI-compatible sensors have appeared in the literature over the last 20 years. The author classifies these sensors into several categories and subcategories, depending on the sensing element placement, method of application, and measure and type. The author includes five in-house-designed fiber Bragg grating based sensors and shares experience in acquiring physiological measurements during MRI scans. This paper aims to systematize the knowledge of fiber-optic techniques for recording life functions and to indicate the current directions of development in this area.

  4. An analytical method for estimating the {sup 14}N nuclear quadrupole resonance parameters of organic compounds with complex free induction decays for radiation effects studies

    SciTech Connect

    Iselin, L.H.

    1992-12-31

    The use of {sup 14}N nuclear quadrupole resonance (NQR) as a radiation dosimetry tool has only recently been explored. An analytical method for analyzing {sup 14}N NQR complex free induction decays is presented with the background necessary to conduct pulsed NQR experiments. The {sup 14}N NQR energy levels and possible transitions are derived in step-by-step detail. The components of a pulsed NQR spectrometer are discussed along with the experimental techniques for conducting radiation effects experiments using the spectrometer. Three data analysis techniques -- the power spectral density Fourier transform, state space singular value decomposition (HSVD), and nonlinear curve fitting (using the downhill simplex method of global optimization and the Levenberg-Marquart method) -- are explained. These three techniques are integrated into an analytical method which uses these numerical techniques in this order to determine the physical NQR parameters. Sample data sets of urea and guanidine sulfate data are used to demonstrate how these methods can be employed to analyze both simple and complex free induction decays. By determining baseline values for biologically significant organics, radiation effects on the NQR parameters can be studied to provide a link between current radiation dosimetry techniques and the biological effects of radiation.

  5. Fiber-optic sensors for monitoring patient physiological parameters: a review of applicable technologies and relevance to use during magnetic resonance imaging procedures

    NASA Astrophysics Data System (ADS)

    Dziuda, Łukasz

    2015-01-01

    The issues involved with recording vital functions in the magnetic resonance imaging (MRI) environment using fiber-optic sensors are considered in this paper. Basic physiological parameters, such as respiration and heart rate, are fundamental for predicting the risk of anxiety, panic, and claustrophobic episodes in patients undergoing MRI examinations. Electronic transducers are generally hazardous to the patient and are prone to erroneous operation in heavily electromagnetically penetrated MRI environments; however, nonmetallic fiber-optic sensors are inherently immune to electromagnetic effects and will be crucial for acquiring the above-mentioned physiological parameters. Forty-seven MRI-tested or potentially MRI-compatible sensors have appeared in the literature over the last 20 years. The author classifies these sensors into several categories and subcategories, depending on the sensing element placement, method of application, and measurand type. The author includes five in-house-designed fiber Bragg grating based sensors and shares experience in acquiring physiological measurements during MRI scans. This paper aims to systematize the knowledge of fiber-optic techniques for recording life functions and to indicate the current directions of development in this area.

  6. Evaluation of Nutritional Biochemical Parameters in Haemodialysis Patients over a Ten-year Period

    PubMed Central

    Alfonso, AIQ; Castillo, RF; Jimenez, FJ Gomez; Negrillo, AM Nuñez

    2015-01-01

    ABSTRACT Aim: Protein-energy malnutrition as well as systemic inflammation and metabolic disorders are common in patients with chronic kidney failure who require renal replacement therapy (haemodialysis). Such malnutrition is a factor that significantly contributes to their morbidity and mortality. This study evaluated the nutritional status of haemodialysis patients by assessing biochemical and anthropometric parameters in order to determine whether these patients suffered disorders reflecting nutritional deterioration directly related to time on haemodialysis. Subjects and Method: This research comprised 90 patients of both genders with chronic kidney failure, who regularly received haemodialysis at our unit over a period of ten years. The patients' blood was tested quarterly for plasma albumin, total cholesterol and total proteins, and tested monthly for transferrin. The patients' weight, height and body mass index (BMI) were monitored. Body mass index was calculated using the formula: weight (kg)/height (m2) and classified in one of the following categories defined in the World Health Organization (WHO) Global Database on Body Mass Index: (i) underweight [BMI < 18.50], (ii) normal [BMI 18.50 – 24.99], (iii) overweight [BMI 25 – 29.99], (iv) obese [BMI ≥ 30]. Results: In the ten-year period of the study, the patients experienced a substantial decline in their biochemical parameters. Nevertheless, their BMI did not show any significant changes despite the patients' state of malnutrition. Conclusions: The prevalence of malnutrition in haemodialysis patients was evident. Nevertheless, the BMI of the subjects did not correspond to the biochemical parameters measured. Consequently, the results showed that the nutritional deterioration of these patients was mainly reflected in their biochemical parameters rather than in their anthropometric measurements. PMID:26426172

  7. A prospective evaluation of cardiovascular magnetic resonance measures of dyssynchrony in the prediction of response to cardiac resynchronization therapy

    PubMed Central

    2014-01-01

    Background Many patients with electrical dyssynchrony who undergo cardiac resynchronization therapy (CRT) do not obtain substantial benefit. Assessing mechanical dyssynchrony may improve patient selection. Results from studies using echocardiographic imaging to measure dyssynchrony have ultimately proved disappointing. We sought to evaluate cardiac motion in patients with heart failure and electrical dyssynchrony using cardiovascular magnetic resonance (CMR). We developed a framework for comparing measures of myocardial mechanics and evaluated how well they predicted response to CRT. Methods CMR was performed at 1.5 Tesla prior to CRT. Steady-state free precession (SSFP) cine images and complementary modulation of magnetization (CSPAMM) tagged cine images were acquired. Images were processed using a novel framework to extract regional ventricular volume-change, thickening and deformation fields (strain). A systolic dyssynchrony index (SDI) for all parameters within a 16-segment model of the ventricle was computed with high SDI denoting more dyssynchrony. Once identified, the optimal measure was applied to a second patient population to determine its utility as a predictor of CRT response compared to current accepted predictors (QRS duration, LBBB morphology and scar burden). Results Forty-four patients were recruited in the first phase (91% male, 63.3 ± 14.1 years; 80% NYHA class III) with mean QRSd 154 ± 24 ms. Twenty-one out of 44 (48%) patients showed reverse remodelling (RR) with a decrease in end systolic volume (ESV) ≥ 15% at 6 months. Volume-change SDI was the strongest predictor of RR (PR 5.67; 95% CI 1.95-16.5; P = 0.003). SDI derived from myocardial strain was least predictive. Volume-change SDI was applied as a predictor of RR to a second population of 50 patients (70% male, mean age 68.6 ± 12.2 years, 76% NYHA class III) with mean QRSd 146 ± 21 ms. When compared to QRSd, LBBB morphology and scar burden, volume

  8. Interference effect in the dipole and nondipole anisotropy parameters of the Kr 4p photoelectrons in the vicinity of the Kr (3d){sup -1{yields}}np resonant excitations

    SciTech Connect

    Ricz, S.; Ricsoka, T.; Holste, K.; Borovik, A. Jr.; Bernhardt, D.; Schippers, S.; Mueller, A.; Koever, A.; Varga, D.

    2010-04-15

    The angular distribution of the Kr 4p photoelectrons was investigated in the photon energy range of the (3d){sup -1{yields}}np resonant excitations. The experimental dipole ({beta}) and nondipole ({gamma} and {delta}) anisotropy parameters were determined for the spin-orbit components of the Kr 4p shell. A simple theoretical model was developed for the description of the photoionization and excitation processes. An interference effect was observed between the direct photoionization and the resonant excitation participator Auger decay processes in the photon energy dependence of the experimental anisotropy parameters.

  9. Site-specific experiments on folding/unfolding of Jun coiled coils: thermodynamic and kinetic parameters from spin inversion transfer nuclear magnetic resonance at leucine-18.

    PubMed

    d'Avignon, D André; Bretthorst, G Larry; Holtzer, Marilyn Emerson; Schwarz, Kathleen A; Angeletti, Ruth Hogue; Mints, Lisa; Holtzer, Alfred

    2006-10-15

    The 32-residue leucine zipper subsequence, called here Jun-lz, associates in benign media to form a parallel two-stranded coiled coil. Studies are reported of its thermal unfolding/folding transition by circular dichroism (CD) on samples of natural isotopic abundance and by both equilibrium and spin inversion transfer (SIT) nuclear magnetic resonance (NMR) on samples labeled at the leucine-18 alpha-carbon with 99% 13C. The data cover a wide range of temperature and concentration, and show that Jun-lz unfolds below room temperature, being far less stable than some other leucine zippers such as GCN4. 13C-NMR shows two well-separated resonances. We ascribe the upfield one to 13C spins on unfolded single chains and the downfield one to 13C spins on coiled-coil dimers. Their relative intensities provide a measure of the unfolding equilibrium constant. In SIT NMR, the recovery of the equilibrium magnetization after one resonance is inverted is modulated in part by the unfolding and folding rate constants, which are accessible from the data. Global Bayesian analysis of the equilibrium and SIT NMR data provide values for the standard enthalpy, entropy, and heat capacity of unfolding, and show the latter to be unusually large. The CD results are compatible with the NMR findings. Global Bayesian analysis of the SIT NMR data yields the corresponding activation parameters for unfolding and folding. The results show that both reaction directions are activated processes. Activation for unfolding is entropy driven, enthalpy opposed. Activation for folding is strongly enthalpy opposed and somewhat entropy opposed, falsifying the idea that the barrier for folding is solely due to a purely entropic search for properly registered partners. The activation heat capacity is much larger for folding, so almost the entire overall change is due to the folding direction. This latter finding, if it applies to GCN4 leucine zippers, clears up an extant apparent disagreement between folding rate

  10. Evaluating Swallowing Muscles Essential for Hyolaryngeal Elevation by Using Muscle Functional Magnetic Resonance Imaging

    SciTech Connect

    Pearson, William G.; Hindson, David F.; Langmore, Susan E.; Zumwalt, Ann C.

    2013-03-01

    Purpose: Reduced hyolaryngeal elevation, a critical event in swallowing, is associated with radiation therapy. Two muscle groups that suspend the hyoid, larynx, and pharynx have been proposed to elevate the hyolaryngeal complex: the suprahyoid and longitudinal pharyngeal muscles. Thought to assist both groups is the thyrohyoid, a muscle intrinsic to the hyolaryngeal complex. Intensity modulated radiation therapy guidelines designed to preserve structures important to swallowing currently exclude the suprahyoid and thyrohyoid muscles. This study used muscle functional magnetic resonance imaging (mfMRI) in normal healthy adults to determine whether both muscle groups are active in swallowing and to test therapeutic exercises thought to be specific to hyolaryngeal elevation. Methods and Materials: mfMRI data were acquired from 11 healthy subjects before and after normal swallowing and after swallowing exercise regimens (the Mendelsohn maneuver and effortful pitch glide). Whole-muscle transverse relaxation time (T2 signal, measured in milliseconds) profiles of 7 test muscles were used to evaluate the physiologic response of each muscle to each condition. Changes in effect size (using the Cohen d measure) of whole-muscle T2 profiles were used to determine which muscles underlie swallowing and swallowing exercises. Results: Post-swallowing effect size changes (where a d value of >0.20 indicates significant activity during swallowing) for the T2 signal profile of the thyrohyoid was a d value of 0.09; a d value of 0.40 for the mylohyoid, 0.80 for the geniohyoid, 0.04 for the anterior digastric, and 0.25 for the posterior digastric-stylohyoid in the suprahyoid muscle group; and d values of 0.47 for the palatopharyngeus and 0.28 for the stylopharyngeus muscles in the longitudinal pharyngeal muscle group. The Mendelsohn maneuver and effortful pitch glide swallowing exercises showed significant effect size changes for all muscles tested, except for the thyrohyoid. Conclusions

  11. Quantitative Evaluation of Mitral Regurgitation Secondary to Mitral Valve Prolapse by Magnetic Resonance Imaging and Echocardiography.

    PubMed

    Le Goffic, Caroline; Toledano, Manuel; Ennezat, Pierre-Vladimir; Binda, Camille; Castel, Anne-Laure; Delelis, François; Graux, Pierre; Tribouilloy, Christophe; Maréchaux, Sylvestre

    2015-11-01

    The present prospective study was designed to evaluate the accuracy of quantitative assessment of mitral regurgitant fraction (MRF) by echocardiography and cardiac magnetic resonance imaging (cMRI) in the modern era using as reference method the blinded multiparametric integrative assessment of mitral regurgitation (MR) severity. 2-Dimensional (2D) and 3-dimensional (3D) MRF by echocardiography (2D echo MRF and 3D echo MRF) were obtained by measuring the difference in left ventricular (LV) total stroke volume (obtained from either 2D or 3D acquisition) and aortic forward stroke volume normalized to LV total stroke volume. MRF was calculated by cMRI using either (1) (LV stroke volume - systolic aortic outflow volume by phase contrast)/LV stroke volume (cMRI MRF [volumetric]) or (2) (mitral inflow volume - systolic aortic outflow volume)/mitral inflow volume (cMRI MRF [phase contrast]). Six patients had 1 + MR, 6 patients had 2 + MR, 12 patients had 3 + MR, and 10 had 4 + MR. A significant correlation was observed between MR grading and 2D echo MRF (r = 0.60, p <0.0001) and 3D echo MRF (r = 0.79, p <0.0001), cMRI MRF (volumetric) (r = 0.87, p <0.0001), and cMRI MRF (phase contrast r = 0.72, p <0.001). The accuracy of MRF for the diagnosis of MR ≥3+ or 4+ was the highest with cMRI MRF (volumetric) (area under the receiver-operating characteristic curve [AUC] = 0.98), followed by 3D echo MRF (AUC = 0.96), 2D echo MRF (AUC = 0.90), and cMRI MRF (phase contrast; AUC = 0.83). In conclusion, MRF by cMRI (volumetric method) and 3D echo MRF had the highest diagnostic value to detect significant MR, whereas the diagnostic value of 2D echo MRF and cMRI MRF (phase contrast) was lower. Hence, the present study suggests that both cMRI (volumetric method) and 3D echo represent best approaches for calculating MRF.

  12. Paraganglioma of the heart. The value of magnetic resonance imaging in the preoperative evaluation.

    PubMed

    Conti, V R; Saydjari, R; Amparo, E G

    1986-10-01

    Although the 131I-metaiodobenzylguanidine scan has proven reliable in identifying mediastinal paragangliomas, further localization has usually required dynamic computerized tomographic scanning which requires rapid bolus injection of contrast material. In the case presented herein, magnetic resonance imaging provided accurate preoperative localization and added important anatomic detail that was not appreciated with dynamic computerized tomograms or with other studies. Magnetic resonance imaging can accurately localize cardiac paragangliomas without injection of contrast material and may provide more detailed information for better guidance for surgical excision.

  13. Evaluation of stimulus parameters and electrode geometry for an effective suprachoroidal retinal prosthesis.

    PubMed

    Shivdasani, Mohit N; Luu, Chi D; Cicione, Rosemary; Fallon, James B; Allen, Penny J; Leuenberger, James; Suaning, Gregg J; Lovell, Nigel H; Shepherd, Robert K; Williams, Chris E

    2010-06-01

    Several approaches have been proposed for placement of retinal prostheses: epiretinal, subretinal and suprachoroidal. We aimed to systematically evaluate the effectiveness of varying a range of stimulus parameters and electrode geometry for a suprachoroidal electrode array, using cortical evoked responses to monopolar electrical stimulation in cats. Our results indicate that charge thresholds were not dependent on electrode size, pulse widths or position of the return electrode tested, but were dependent on the number of sites stimulated in parallel. Further, we found that the combination of monopolar stimulation with large diameter electrodes, wide pulse widths and parallel stimulation minimized the voltage requirements for stimulation. These results provide useful insights for the design specifications of a low voltage suprachoroidal stimulator.

  14. The stable status evaluation for female breast implant surgery by calculating related physics parameters.

    PubMed

    Sun, Shuh-Ping; Hsu, Ko-Wen; Chen, Jing-Shyr

    2008-05-01

    Cosmetic doctor utilizes the position, size and shapes of female's breast to judge whether the breast is under steady-state condition after breast implant plastic surgery. Since, doctor evaluates the breast condition with the subjective discrimination (such as vision, sense of touch) without using the objective physical parameters auxiliary. This study uses the 3D optics scanner editing 3D image to obtain full-scale 3D female breasts image. The CAD system converts the breast position, size and shapes, as the length of the curve between UBL (upper breast line) and NBL (nipple base line), the length of the curve between NBL and LBL (lower breast line), breast volume and breasts congruence rate. The stability after the breast implant plastic surgery is one of the important successful indexes of plastic surgery, so with the continuity analysis the breast curve length, volume and congruence rate can let the doctor really grasp the stability of the breast after plastic surgery.

  15. Magnetic bead processor for rapid evaluation and optimization of parameters for phosphopeptide enrichment.

    PubMed

    Ficarro, Scott B; Adelmant, Guillaume; Tomar, Maria N; Zhang, Yi; Cheng, Vincent J; Marto, Jarrod A

    2009-06-01

    Qualitative and quantitative analysis of phosphorylation continues to be both an important and a challenging experimental paradigm in proteomics-based research. Unfortunately researchers face difficulties inherent to the optimization of complex, multivariable methods and their application to the analysis of rare and often experimentally intractable phosphorylated peptides. Here we describe a platform based on manipulation of magnetic beads in a 96-well format that facilitates rapid evaluation of experimental parameters required for enrichment of phosphopeptides. Optimized methods provided for automated enrichment and subsequent LC-MS/MS detection of over 1000 unique phosphopeptides (approximately 1% FDR) from 50 microg of cell lysates. In addition we demonstrate use of this platform for identification of phosphopeptides derived from proteins separated by SDS-PAGE and visualized near the detection limit of silver staining.

  16. Immunologic parameters evaluations in Nile tilapia (Oreochromis niloticus) exposed to sublethal concentrations of diazinon.

    PubMed

    Girón-Pérez, M I; Velázquez-Fernández, J; Díaz-Resendiz, K; Díaz-Salas, F; Canto-Montero, C; Medina-Díaz, I; Robledo-Marenco, M; Rojas-García, A; Zaitseva, G

    2009-08-01

    Fish resistance to microorganisms depends basically on the immune response. Although there are several studies on the diazinon mammalian immunotoxicity, in the case of fish there are only few. The aim of present study was to evaluate the effect of diazinon on immunological parameters (relative spleen weight, splenocytes count, lysozyme activity, respiratory burst and IgM concentration) in Nile tilapia. Diazinon at sublethal concentrations (0.39 and 0.78 mg/L) did not alter RSW, splenocytes count or lysozyme activity. However, at the highest concentration tested (1.96 mg/L) diazinon significantly increased respiratory burst and IgM concentration. In summary, diazinon (and perhaps other pesticides) could alter immunological response and induce oxidative stress.

  17. Evaluation of the toxic and genotoxic potential of acid mine drainage using physicochemical parameters and bioassays.

    PubMed

    Netto, E; Madeira, R A; Silveira, F Z; Fiori, M A; Angioleto, E; Pich, C T; Geremias, R

    2013-05-01

    Carboniferous activity generates acid mine drainage (AMD) which is capable of unleashing toxic effects on the exposed biota. The aim of this study was to evaluate the toxic and genotoxic potential of untreated-AMD and AMD treated with calcinated sediment, using physicochemical parameters and bioassays. Results revealed that untreated-AMD presented low pH values and elevated concentrations of the metals Fe, Al, Mn, Zn and Cu. High acute toxicity was observed in Artemia sp. and Daphnia magna, and sub-chronic toxicity and genotoxicity in Allium cepa L. as well as scission of plasmid DNA exposed to untreated-AMD. Treatment of AMD with calcinated sediment promoted the reduction of acidity and the removal of metals, as well as a reduction in toxic and genotoxic effects. In conclusion, the calcinated sediment can be used as an alternative AMD treatment.

  18. Severe Portal Hypertension in Cirrhosis: Evaluation of Perfusion Parameters with Contrast-Enhanced Ultrasonography

    PubMed Central

    Sohn, Joo Hyun; Kim, Yongsoo; Kim, Jinoo

    2015-01-01

    Objective To investigate the role of contrast-enhanced ultrasonography (CEUS) and Doppler ultrasonography (DUS) in the diagnosis of severe portal hypertension (PH) in patients with liver cirrhosis (LC). Methods Patients with PH scheduled to receive hepatic venous pressure gradient (HVPG) measurement were recruited for this study. Hepatic DUS and CEUS were performed successively. Several Doppler and CEUS parameters were explored for correlation with HVPG values and their association with severe PH (≥ 12 mmHg of HVPG). Comparison of the parameters between the severe and non-severe PH groups and their correlation with HVPG values was evaluated. A receiver operating characteristic (ROC) curve analysis was also performed to investigate the performance in order to diagnose severe PH. Results Fifty-three consecutive patients were enrolled in this study. Among them, 43 patients did not have significant ascites. Compared with the non-severe PH group, portal venous velocity and intrahepatic transit time (ITT) were significantly reduced in the severe PH group (all p<0.05). Difference between inspiratory and expiratory hepatic venous damping indices (ΔHVDI), hepatic venous arrival time (HVAT) and ITT moderately correlated with HVPG (r = -0.358, -0.338, and -0.613, respectively). Areas under the curves for severe PH were 0.94 of ITT and 0.72 of HVAT, respectively (all p<0.05). ITT under 6 seconds indicated severe PH with a sensitivity of 92% and a specificity of 89%. Conclusions Hepatic CEUS may be more useful in estimating the HVPG value and determining the presence of severe PH compared to DUS, and ITT was the most accurate parameter to diagnose severe PH. PMID:25798930

  19. Optimization strategies for evaluation of brain hemodynamic parameters with qBOLD technique.

    PubMed

    Wang, Xiaoqi; Sukstanskii, Alexander L; Yablonskiy, Dmitriy A

    2013-04-01

    Quantitative blood oxygenation level dependent technique provides an MRI-based method to measure tissue hemodynamic parameters such as oxygen extraction fraction and deoxyhemoglobin-containing (veins and prevenous part of capillaries) cerebral blood volume fraction. It is based on a theory of MR signal dephasing in the presence of blood vessel network and experimental method-gradient echo sampling of spin echo previously proposed and validated on phantoms and animals. In vivo human studies also demonstrated feasibility of this approach but also recognized that obtaining reliable results requires high signal-to-noise ratio in the data. In this paper, we analyze in detail the uncertainties of the quantitative blood oxygenation level dependent parameter estimates in the framework of the Bayesian probability theory, namely, we examine how the estimated parameters oxygen extraction fraction and deoxygenated cerebral blood volume fraction depend on their "true values," signal-to-noise ratio, and data sampling strategies. On the basis of this analysis, we develop strategies for optimization of the quantitative blood oxygenation level dependent technique for deoxygenated cerebral blood volume and oxygen extraction fraction evaluation. In particular, it is demonstrated that the use of gradient echo sampling of spin echo sequence allows substantial decrease of measurement errors as the data are acquired on both sides of spin echo. We test our theory on phantom mimicking the structure of blood vessel network. A 3D gradient echo sampling of spin echo pulse sequence is used for the acquisition of the MRI signal that was subsequently analyzed by Bayesian Application Software. The experimental results demonstrated a good agreement with theoretical predictions.

  20. Evaluation of crack parameters by a nonlinear frequency-mixing laser ultrasonics method.

    PubMed

    Mezil, Sylvain; Chigarev, Nikolay; Tournat, Vincent; Gusev, Vitalyi

    2016-07-01

    The local evaluation of several parameters of a crack is realized with a nonlinear laser ultrasonic method. The method is based on the sample excitation by two laser beams, independently intensity modulated at two cyclic frequencies ωH and ωL (ωH≫ωL) and on the detection of nonlinear frequency-mixing ultrasonic components at frequencies ωH±nωL (n an integer). Frequency-mixing is a nonlinear process originating from the modulation of the crack state at low frequency ωL by laser-induced thermo-elastic stresses, which causes in turn the modulation of the acoustic waves at frequency ωH reflected/transmitted by the crack. We carry experiments with increasing laser power and observe a non-monotonous variation in the amplitude of up to 6 nonlinear sidelobes. We also improve a previously introduced theoretical model which leads to interpreting the experimental observations by the combined action on the crack of the thermo-elastic waves at low frequency ωL and of the stationary thermo-elastic stresses at ω=0. The latter are induced by the average laser power absorbed by the sample. While thermo-elastic wave can periodically modulate the parameters of the crack up to its periodic opening/closing, the stationary heating could cause complete local closure of the crack. By fitting the experimental amplitude evolutions for all monitored sidelobes with the theoretically predicted ones, various local parameters of the crack are extracted, including its local width and effective rigidity.

  1. A resonator sensor for measurement of intraocular pressure--evaluation in an in vitro pig-eye model.

    PubMed

    Eklund, A; Bäcklund, T; Lindahl, O A

    2000-08-01

    Intraocular pressure (IOP) measurement is performed routinely at every eye clinic. High IOP, which can be a sign of glaucoma, can lead to degeneration of the retina and can cause blindness. In this study we developed a resonator sensor for IOP measurement based on an oscillator consisting of a piezoelectric element made of lead zirconate titanate, a flat contact piece of nylon and a feedback circuit. The aim of this study was to evaluate the new sensor's ability to determine lOP in an in vitro pig-eye model. Six eyes from four pigs were removed and fixed in agar. They were then pressurized by a saline column (10-35 cm H2O) through a cannula inserted into the vitreous chamber. The IOP was measured with the resonator sensor applied to cornea. An Alcon applanation pneumatonometer and a standard Viggo-Spectramed pressure sensor connected to the saline column were used as references. The IOP as measured with the resonator sensor correlated well with the pressure elicited by the saline column for individual eyes (r = 0.96-0.99, n = 60) and for all eyes (r = 0.92, n = 360). The correlation between the resonance sensor and the pneumatonometer was r = 0.92 (n = 360). The pneumatonometer also showed a good correlation with the saline column (r = 0.98, n = 360). We conclude that our in vitro pig-eye model made it possible to induce reproducible variation in IOP, and measurement of that pressure with the newly developed resonator sensor gave very promising results for development of a clinically applicable IOP tonometer with unique properties.

  2. A comparative evaluation of semen parameters in pre- and post-Hurricane Katrina human population.

    PubMed

    Baran, Caner; Hellstrom, Wayne J; Sikka, Suresh C

    2015-01-01

    A natural disaster leading to accumulation of environmental contaminants may have substantial effects on the male reproductive system. Our aim was to compare and assess semen parameters in a normospermic population residing in the Southern Louisiana, USA area pre- and post-Hurricane Katrina. We retrospectively evaluated semen analyses data (n = 3452) of 1855 patients who attended the Tulane University Andrology/Fertility Clinic between 1999 and 2013. The study inclusion criteria were men whose semen analyses showed ≥ 1.5 ml volume; ≥15 million ml -1 sperm concentration; ≥39 million total sperm count; ≥40% motility; >30% morphology, with an abstinence interval of 2-7 days. After the inclusion criteria applied to the population, 367 normospermic patients were included in the study. Descriptive statistics and group-based analyses were performed to interpret the differences between the pre-Katrina (Group 1, 1999-2005) and the post-Katrina (Group 2, 2006-2013) populations. There were significant differences in motility, morphology, number of white blood cell, immature germ cell count, pH and presence of sperm agglutination, but surprisingly there were no significant differences in sperm count between the two populations. This long-term comparative analysis further documents that a major natural disaster with its accompanied environmental issues can influence certain semen parameters (e.g., motility and morphology) and, by extension, fertility potential of the population of such areas.

  3. A comparative evaluation of semen parameters in pre- and post-Hurricane Katrina human population

    PubMed Central

    Baran, Caner; Hellstrom, Wayne J; Sikka, Suresh C

    2015-01-01

    A natural disaster leading to accumulation of environmental contaminants may have substantial effects on the male reproductive system. Our aim was to compare and assess semen parameters in a normospermic population residing in the Southern Louisiana, USA area pre- and post-Hurricane Katrina. We retrospectively evaluated semen analyses data (n = 3452) of 1855 patients who attended the Tulane University Andrology/Fertility Clinic between 1999 and 2013. The study inclusion criteria were men whose semen analyses showed ≥ 1.5 ml volume; ≥15 million ml-1 sperm concentration; ≥39 million total sperm count; ≥40% motility; >30% morphology, with an abstinence interval of 2–7 days. After the inclusion criteria applied to the population, 367 normospermic patients were included in the study. Descriptive statistics and group-based analyses were performed to interpret the differences between the pre-Katrina (Group 1, 1999–2005) and the post-Katrina (Group 2, 2006–2013) populations. There were significant differences in motility, morphology, number of white blood cell, immature germ cell count, pH and presence of sperm agglutination, but surprisingly there were no significant differences in sperm count between the two populations. This long-term comparative analysis further documents that a major natural disaster with its accompanied environmental issues can influence certain semen parameters (e.g., motility and morphology) and, by extension, fertility potential of the population of such areas. PMID:25677132

  4. Evaluating the Surface Topography of Pyrolytic Carbon Finger Prostheses through Measurement of Various Roughness Parameters

    PubMed Central

    Naylor, Andrew; Talwalkar, Sumedh C.; Trail, Ian A.; Joyce, Thomas J.

    2016-01-01

    The articulating surfaces of four different sizes of unused pyrolytic carbon proximal interphalangeal prostheses (PIP) were evaluated though measuring several topographical parameters using a white light interferometer: average roughness (Sa); root mean-square roughness (Sq); skewness (Ssk); and kurtosis (Sku). The radii of the articulating surfaces were measured using a coordinate measuring machine, and were found to be: 2.5, 3.3, 4.2 and 4.7 mm for proximal, and 4.0, 5.1, 5.6 and 6.3 mm for medial components. ANOVA was used to assess the relationship between the component radii and each roughness parameter. Sa, Sq and Ssk correlated negatively with radius (p = 0.001, 0.001, 0.023), whilst Sku correlated positively with radius (p = 0.03). Ergo, the surfaces with the largest radii possessed the better topographical characteristics: low roughness, negative skewness, high kurtosis. Conversely, the surfaces with the smallest radii had poorer topographical characteristics. PMID:27089375

  5. Introduction of Environmentally Degradable Parameters to Evaluate the Biodegradability of Biodegradable Polymers

    PubMed Central

    Yang, Chao; Song, Cunjiang; Geng, Weitao; Li, Qiang; Wang, Yuanyuan; Kong, Meimei; Wang, Shufang

    2012-01-01

    Environmentally Degradable Parameter (EdK) is of importance in the describing of biodegradability of environmentally biodegradable polymers (BDPs). In this study, a concept EdK was introduced. A test procedure of using the ISO 14852 method and detecting the evolved carbon dioxide as an analytical parameter was developed, and the calculated EdK was used as an indicator for the ultimate biodegradability of materials. Starch and polyethylene used as reference materials were defined as the EdK values of 100 and 0, respectively. Natural soil samples were inoculated into bioreactors, followed by determining the rates of biodegradation of the reference materials and 15 commercial BDPs over a 2-week test period. Finally, a formula was deduced to calculate the value of EdK for each material. The EdK values of the tested materials have a positive correlation to their biodegradation rates in the simulated soil environment, and they indicated the relative biodegradation rate of each material among all the tested materials. Therefore, the EdK was shown to be a reliable indicator for quantitatively evaluating the potential biodegradability of BDPs in the natural environment. PMID:22675455

  6. Evaluating kinetic models for preferential CO-oxidation catalysts using optimization-based parameter estimation

    NASA Astrophysics Data System (ADS)

    Baughman, Adam C.; Huang, Xinqun; Martin, Lealon L.

    2012-07-01

    We adapt a general-purpose optimization-based parameter estimation technique previously described in the literature [1] to evaluate the suitability of a number of common kinetic models for the representation of key performance characteristics (conversion and selectivity) of catalysts used for the preferential oxidation of CO in the presence of H2. We find that, for process engineering applications, there is no clear practical advantage to using mechanistically based kinetic models (e.g. Langmuir-Hinshelwood) unless the precise chemical mechanism is known. Empirical rate models are found generally to provide equivalent or better simulations of key performance variables for a diverse group of catalyst formulations. Furthermore, we demonstrate that the water-gas-shift (WGS) reaction is relevant within PROX reaction systems under conditons containing high fractions of CO2 and H2, confirming the expectations of Choi and Stenger (2004) [2]. Finally, we attempt to identify any emergent trends in kinetic parameters among catalysts sharing similar active metal or metal oxide components. Unfortunately, apart from confirming that the activation barrier for CO oxidation is generally less than the barrier for H2 oxidation (an expected relationship for PROX catalysts), no such trends are found.

  7. Electrical parameter evaluation of a 1 MW HTS motor via analysis and experiments

    NASA Astrophysics Data System (ADS)

    Baik, S. K.; Kwon, Y. K.; Kim, H. M.; Kim, S. H.; Lee, J. D.; Kim, Y. C.; Park, H. J.; Kwon, W. S.; Park, G. S.

    2009-06-01

    A 1 MW class HTS (high-temperature superconducting) synchronous motor has been developed. Design concerns of the developed motor are focused on smaller machine size and higher efficiency than conventional motors or generators with the same rating simultaneously reducing expensive Bi-2223 HTS wire which is used for superconducting field coil carrying the operating current around 30 K (-243 °C). Influence of an important parameter, synchronous reactance, has been analyzed on the machine performances such as voltage variation and output power during motor and generator operation. The developed motor was also analyzed by three-dimensional electromagnetic FEM (finite element method) to get magnetic field distribution, inductance, electromagnetic stress and so forth. This motor is aimed to be utilized for industrial application such as large motors operating in large plants. The HTS field coil of the developed motor is cooled by way of Neon thermosiphon mechanism and the stator (armature) coil is cooled by water through hollow copper conductor. This paper also describes evaluation of some electrical parameters from performance test results which were obtained at steady state in generator and motor mode of our HTS machine.

  8. Evaluation of bone metabolism in newborn twins using quantitative ultrasound and biochemical parameters.

    PubMed

    Kara, Semra; Güzoğlu, Nilüfer; Göçer, Emine; Arıkan, Fatma Inci; Dilmen, Uğur; Dallar Bilge, Yıldız

    2016-03-01

    Metabolic bone disease (MBD) is one of the important complications of prematurity. Early and adequate nutritional interventions may reduce the incidence and potential complications of MBD. The present study aimed to evaluate bone metabolism in twins via biochemical parameters and quantitative ultrasound (QUS) and to compare the results between twin pairs. Moreover, twin infants were evaluated in terms of potential risk factors likely to have impact on MBD. Forty-three pairs of twins were included in the study. Serum calcium, phosphorus, magnesium, and alkaline phosphatase concentrations were assessed and bone mineral density was measured using QUS (speed of sound, SOS) at postnatal 30 d. Co-twin with the higher birth weight was assigned to Group 1 (n = 36) and the other twin was assigned to Group 2 (n = 36). Birth weight and head circumference were significantly higher in the infants of Group 1 compared with Group 2. No significant difference was found among the groups in terms of gender, history of resuscitation, length of stay in intensive care unit (ICU) or in the incubator, duration of total parenteral nutrition (TPN), type of nutrition, vitamin D use, biochemical parameters, and the SOS value. The factors likely to affect SOS, including type of pregnancy, maternal drug use, gender of infant, birth weight, head circumference at birth, gestational week, length of stay at the ICU, duration of TPN, type of nutrition, resuscitation, vitamin D use, and levels of calcium, phosphorus, magnesium, and alkaline phosphatase were entered into the model. The phosphorus level and the maternal drug use were found to be the factors that significantly reduced SOS, whereas pregnancy after assisted reproductive techniques was found to be a significant enhancing factor.

  9. Evaluating the safety of intracameral bevacizumab application using oxidative stress and apoptotic parameters in corneal tissue

    PubMed Central

    Akal, Ali; Ulas, Turgay; Goncu, Tugba; Guldur, Muhammet Emin; Kocarslan, Sezen; Taskin, Abdullah; Sezen, Hatice; Ozkan, Kudret; Yilmaz, Omer Faruk; Buyukhatipoglu, Hakan

    2015-01-01

    AIM To investigate the possible effects of intracameral bevacizumab on oxidative stress parameters and apoptosis in corneal tissue. METHODS In total, 30 rats were assigned randomly into the following three groups of 10 rats each: a sham group (Group 1; n=10), a control group [Group 2; balanced salt solution (BSS) was administered at 0.01 mL; n=10], and a treatment group (Group 3; bevacizumab was administered at 0.25 mg/0.01 mL; n=10). The total antioxidant status (TAS) and the total oxidant status (TOS) in the corneal tissue and blood samples were measured, and the oxidative stress index (OSI) was calculated. Additionally, corneal tissue histopathology was evaluated for caspase-3 and -8 staining and apoptotic activity. RESULTS In the blood samples, the TAS, TOS, and OSI levels were not significantly different (all P>0.05). Compared with the sham and control groups, the TOS and OSI levels in the corneal tissues were significantly different in the bevacizumab group (all P<0.05). No statistically significant differences were observed between the sham and control groups (all P>0.05). However, compared with the sham and control groups, greater immunohistochemical staining for caspases-3 and -8 and an elevated level of apoptotic activity were observed in the bevacizumab group. CONCLUSION This study revealed that intracameral bevacizumab injections seemed to be systemically safe but may have elicited local toxic effects in the corneal tissue, as indicated by the oxidative stress parameters and histopathological evaluations. PMID:26309865

  10. Evaluation of ventricular geometry and performance in congenital heart disease utilizing magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Fogel, Mark A.

    1994-05-01

    We have recently embarked on a systematic evaluation of the regional and global mechanical processes of the systemic, morphologic right ventricle (RV) which is in either a single or dual chambered circulation as well as single left ventricles (LV). An MRI tagging technique which lays down 2 sets of parallel stripes perpendicular to each other on the myocardium as well as standard cine MRI were utilized. Finite strain analysis was applied to the grid lines to derive principle strains and the motion of the intersection points were tracked through systole to determine regional radial shortening and twist. Cine sequences were used to derive the various parameters of ventricular geometry and performance as well as visualizing flow profiles in the aorta. We noted a marked decrease in vol, EF, and CO in the Fontan group of patients when compared to other surgical subgroups. It is hypothesized that atrial stiffening by surgical placement of baffles may contribute to the observed changes in ventricular mechanics. Aortic flow profiles in the reconstructed aorta were noted to be heterogenous across the aortic diameter.

  11. Resonance Raman spectroscopic evaluation of skin carotenoids as a biomarker of carotenoid status for human studies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Resonance Raman Spectroscopy (RRS) is a non-invasive method that has been developed to assess carotenoid status in human tissues including human skin in vivo. Skin carotenoid status, as assessed by RRS, has been suggested as a promising biomarker for use in human studies. This manuscript describes...

  12. Cardiovascular magnetic resonance in the evaluation of heart failure: a luxury or a need?

    PubMed

    D'Andrea, Antonello; Fontana, Marianna; Cocchia, Rosangela; Scarafile, Raffaella; Calabrò, Raffaele; Moon, James C

    2012-01-01

    Heart failure is a common syndrome with multiple causes. Cardiovascular magnetic resonance (CMR), using the available range of technique, is establishing itself as the gold standard noninvasive test for determining the underlying causes, and adding prognostic value, guiding therapy. Progress is continuing and rapid with promising new techniques such as diffuse fibrosis assessment. This article discusses the diverse roles of CMR in heart failure.

  13. Cardiovascular magnetic resonance evaluation of aortic stenosis severity using single plane measurement of effective orifice area

    PubMed Central

    2012-01-01

    Background Transthoracic echocardiography (TTE) is the standard method for the evaluation of the severity of aortic stenosis (AS). Valve effective orifice area (EOA) measured by the continuity equation is one of the most frequently used stenotic indices. However, TTE measurement of aortic valve EOA is not feasible or not reliable in a significant proportion of patients. Cardiovascular magnetic resonance (CMR) has emerged as a non-invasive alternative to evaluate EOA using velocity measurements. The objectives of this study were: 1) to validate a new CMR method using jet shear layer detection (JSLD) based on acoustical source term (AST) concept to estimate the valve EOA; 2) to introduce a simplified JSLD method not requiring vorticity field derivation. Methods and results We performed an in vitro study where EOA was measured by CMR in 4 fixed stenoses (EOA = 0.48, 1.00, 1.38 and 2.11 cm2) under the same steady flow conditions (4-20 L/min). The in vivo study included eight (8) healthy subjects and 37 patients with mild to severe AS (0.72 cm2 ≤ EOA ≤ 1.71 cm2). All subjects underwent TTE and CMR examinations. EOA was determinated by TTE with the use of continuity equation method (TTECONT). For CMR estimation of EOA, we used 3 methods: 1) Continuity equation (CMRCONT); 2) Shear layer detection (CMRJSLD), which was computed from the velocity field of a single CMR velocity profile at the peak systolic phase; 3) Single plane velocity truncation (CMRSPVT), which is a simplified version of CMRJSLD method. There was a good agreement between the EOAs obtained in vitro by the different CMR methods and the EOA predicted from the potential flow theory. In the in vivo study, there was good correlation and concordance between the EOA measured by the TTECONT method versus those measured by each of the CMR methods: CMRCONT (r = 0.88), CMRJSLD (r = 0.93) and CMRSPVT (r = 0.93). The intra- and inter- observer variability of EOA measurements was 5 ± 5% and 9 ± 5% for TTECONT, 2

  14. Radiation-Induced Damage to Microstructure of Parotid Gland: Evaluation Using High-Resolution Magnetic Resonance Imaging

    SciTech Connect

    Kan, Tomoko; Kodani, Kazuhiko; Michimoto, Koichi; Fujii, Shinya; Ogawa, Toshihide

    2010-07-15

    Purpose: To elucidate the radiation-induced damage to the microstructure of the parotid gland using high-resolution magnetic resonance imaging. Methods and Materials: High-resolution magnetic resonance imaging of the parotid gland was performed before radiotherapy (RT) and during the RT period or {<=}3 weeks after RT completion for 12 head-and-neck cancer patients using a 1.5-T scanner with a microscopy coil. The maximal cross-sectional area of the gland was evaluated, and changes in the internal architecture of the gland were assessed both visually and quantitatively. Results: Magnetic resonance images were obtained at a median parotid gland dose of 36 Gy (range, 11-64). According to the quantitative analysis, the maximal cross-sectional area of the gland was reduced, the width of the main duct was narrowed, and the intensity ratio of the main duct lumen to background was significantly decreased after RT (p <.0001). According to the visual assessment, the width of the main duct tended to narrow and the contrast of the duct lumen tended to be decreased, but no significant differences were noted. The visibility of the duct branches was unclear in 10 patients (p = .039), and the septum became dense in 11 patients (p = .006) after RT. Conclusion: High-resolution magnetic resonance imaging is a noninvasive method of evaluating radiation-induced changes to the internal architecture of the parotid gland. Morphologic changes in the irradiated parotid gland were demonstrated during the RT course even when a relatively small dose was delivered to the gland.

  15. Evaluation onto life cycle parameters of Ceriodaphnia silvestrii submitted to 36 days dietary copper exposure.

    PubMed

    Rodgher, Suzelei; Lombardi, Ana Teresa; Gama Melão, Maria da Graça

    2009-09-01

    The present study aimed to investigate the response of several life history parameters (body length and age of primipara, duration of embryonic development, maximum body length, reproduction and survival) of the zooplankton Ceriodaphnia silvestrii while exposed to copper contaminated algae Pseudokirchneriella subcapitata. In order to evaluate chronic exposure on the animal's life history, long-term experimental design was used. Cladocerans were fed with a dietary copper concentration ranging from 3 to 68 fg Cu cell(-1). Low waterborne copper exposure (around 10(-10)molL(-1) free Cu(2+) ions) was kept in the experiments. The results showed that by exposure of cladocerans during 7 days to contaminated food with 68 fg Cu cell(-1), a significant reduction in neonate production, survival and body size were obtained. Inhibition on egg production of zooplankton at 38 fg Cu cell(-1) were observed in 36 days chronic dietary copper exposure. The importance of entire life cycle study to better evaluate cladoceran responses to chronic dietary metal exposure was demonstrated.

  16. Measurement of the CP-Violation Parameter sin2Φ₁ with a New Tagging Method at the Υ(5S) Resonance

    SciTech Connect

    Sato, Y.; Yamamoto, H.; Aihara, H.; Asner, D. M.; Aulchenko, V.; Aushev, T.; Aziz, T.; Bakich, A. M.; Bhardwaj, V.; Bhuyan, B.; Bischofberger, M.; Bondar, A.; Bozek, A.; Bračko, M.; Browder, T. E.; Chang, P.; Chen, P.; Cheon, B. G.; Chilikin, K.; Chistov, R.; Cho, I.-S.; Cho, K.; Choi, S.-K.; Choi, Y.; Dalseno, J.; Doležal, Z.; Drásal, Z.; Eidelman, S.; Epifanov, D.; Fast, J. E.; Gaur, V.; Gabyshev, N.; Goh, Y. M.; Golob, B.; Haba, J.; Hara, T.; Hayasaka, K.; Hayashii, H.; Horii, Y.; Hoshi, Y.; Hou, W.-S.; Hyun, H. J.; Ishikawa, A.; Itoh, R.; Iwabuchi, M.; Iwasaki, Y.; Iwashita, T.; Julius, T.; Kapusta, P.; Kawasaki, T.; Kichimi, H.; Kiesling, C.; Kim, H. J.; Kim, H. O.; Kim, J. B.; Kim, J. H.; Kim, K. T.; Kim, M. J.; Kim, S. K.; Kim, Y. J.; Kinoshita, K.; Ko, B. R.; Kobayashi, N.; Kodyš, P.; Korpar, S.; Križan, P.; Krokovny, P.; Kuhr, T.; Kumar, R.; Kumita, T.; Kuzmin, A.; Kwon, Y.-J.; Lange, J. S.; Lee, S.-H.; Li, J.; Li, Y.; Liu, C.; Liu, Z. Q.; Louvot, R.; McOnie, S.; Miyabayashi, K.; Miyata, H.; Mizuk, R.; Mohanty, G. B.; Moll, A.; Muramatsu, N.; Nakano, E.; Nakao, M.; Nakazawa, H.; Natkaniec, Z.; Nishida, S.; Nishimura, K.; Nitoh, O.; Ogawa, S.; Ohshima, T.; Okuno, S.; Olsen, S. L.; Onuki, Y.; Ostrowicz, W.; Pakhlov, P.; Pakhlova, G.; Park, C. W.; Park, H.; Park, H. K.; Pedlar, T. K.; Petrič, M.; Piilonen, L. E.; Poluektov, A.; Röhrken, M.; Ryu, S.; Sahoo, H.; Sakai, Y.; Sanuki, T.; Schneider, O.; Schwanda, C.; Schwartz, A. J.; Seidl, R.; Senyo, K.; Seon, O.; Sevior, M. E.; Shapkin, M.; Shen, C. P.; Shibata, T.-A.; Shiu, J.-G.; Shwartz, B.; Sibidanov, A.; Simon, F.; Smerkol, P.; Sohn, Y.-S.; Sokolov, A.; Solovieva, E.; Stanič, S.; Starič, M.; Stypula, J.; Sumihama, M.; Sumiyoshi, T.; Tanaka, S.; Tatishvili, G.; Teramoto, Y.; Trabelsi, K.; Uchida, M.; Uglov, T.; Unno, Y.; Uno, S.; Urquijo, P.; Varner, G.; Varvell, K. E.; Wang, C. H.; Wang, M.-Z.; Wang, P.; Wang, X. L.; Watanabe, M.; Watanabe, Y.; Wicht, J.; Won, E.; Yabsley, B. D.; Yamashita, Y.; Yusa, Y.; Zhang, Z. P.; Zhilich, V.; Zhulanov, V.; Zupanc, A.

    2012-04-23

    We report a measurement of the CP-violation parameter sin2Φ₁ at the Υ(5S) resonance using a new tagging method, called “B-π tagging.” In Υ(5S) decays containing a neutral B meson, a charged B, and a charged pion, the neutral B is reconstructed in the J/ψK0SCP-eigenstate decay channel. The initial flavor of the neutral B meson at the moment of the Υ(5S) decay is opposite to that of the charged B and may thus be inferred from the charge of the pion without reconstructing the charged B. From the asymmetry between B-π⁺ and Bπ⁻ tagged J/ψK0S yields, we determine sin2Φ₁=0.57±0.58(stat)±0.06(syst). The results are based on 121 fb⁻¹ of data recorded by the Belle detector at the KEKB e⁺e⁻ collider.

  17. Measurement of the CP-Violation Parameter sin2Φ₁ with a New Tagging Method at the Υ(5S) Resonance

    DOE PAGES

    Sato, Y.; Yamamoto, H.; Aihara, H.; ...

    2012-04-23

    We report a measurement of the CP-violation parameter sin2Φ₁ at the Υ(5S) resonance using a new tagging method, called “B-π tagging.” In Υ(5S) decays containing a neutral B meson, a charged B, and a charged pion, the neutral B is reconstructed in the J/ψK0SCP-eigenstate decay channel. The initial flavor of the neutral B meson at the moment of the Υ(5S) decay is opposite to that of the charged B and may thus be inferred from the charge of the pion without reconstructing the charged B. From the asymmetry between B-π⁺ and Bπ⁻ tagged J/ψK0S yields, we determine sin2Φ₁=0.57±0.58(stat)±0.06(syst). The resultsmore » are based on 121 fb⁻¹ of data recorded by the Belle detector at the KEKB e⁺e⁻ collider.« less

  18. A laser gyro with a four-mirror square resonator: formulas for simulating the dynamics of the synchronisation zone parameters of the frequencies of counterpropagating waves during the device operation in the self-heating regime

    SciTech Connect

    Bondarenko, E A

    2014-04-28

    For a laser gyro with a four-mirror square resonator we have developed a mathematical model, which allows one to simulate the temporal behaviour of the synchronisation zone parameters of the frequencies of counterpropagating waves in a situation when the device operates in the self-heating regime and is switched-on at different initial temperatures. (laser gyroscopes)

  19. Vulnerable atherosclerotic carotid plaque evaluation by ultrasound, computed tomography angiography, and magnetic resonance imaging: an overview.

    PubMed

    Naim, Cyrille; Douziech, Maxime; Therasse, Eric; Robillard, Pierre; Giroux, Marie-France; Arsenault, Frederic; Cloutier, Guy; Soulez, Gilles

    2014-08-01

    Ischemic syndromes associated with carotid atherosclerotic disease are often related to plaque rupture. The benefit of endarterectomy for high-grade carotid stenosis in symptomatic patients has been established. However, in asymptomatic patients, the benefit of endarterectomy remains equivocal. Current research seeks to risk stratify asymptomatic patients by characterizing vulnerable, rupture-prone atherosclerotic plaques. Plaque composition, biology, and biomechanics are studied by noninvasive imaging techniques such as magnetic resonance imaging, computed tomography, ultrasound, and ultrasound elastography. These techniques are at a developmental stage and have yet to be used in clinical practice. This review will describe noninvasive techniques in ultrasound, magnetic resonance imaging, and computed tomography imaging modalities used to characterize atherosclerotic plaque, and will discuss their potential clinical applications, benefits, and drawbacks.

  20. Magnetic Resonance Imaging and Other Imaging Modalities in Diagnostic and Tumor Response Evaluation.

    PubMed

    Lambregts, Doenja M J; Maas, Monique; Stokkel, Marcel P M; Beets-Tan, Regina G H

    2016-07-01

    Functional imaging is emerging as a valuable contributor to the clinical management of patients with rectal cancer. Techniques such as diffusion-weighted magnetic resonance imaging, perfusion imaging, and positron emission tomography can offer meaningful insights into tissue architecture, vascularity, and metabolism. Moreover, new techniques targeting other aspects of tumor biology are now being developed and studied. This study reviews the potential role of functional imaging for the diagnosis, treatment monitoring, and assessment of prognosis in patients with rectal cancer.

  1. In vitro evaluation of genotoxic effects under magnetic resonant coupling wireless power transfer.

    PubMed

    Mizuno, Kohei; Shinohara, Naoki; Miyakoshi, Junji

    2015-04-07

    Wireless power transfer (WPT) technology using the resonant coupling phenomenon has been widely studied, but there are very few studies concerning the possible relationship between WPT exposure and human health. In this study, we investigated whether exposure to magnetic resonant coupling WPT has genotoxic effects on WI38VA13 subcloned 2RA human fibroblast cells. WPT exposure was performed using a helical coil-based exposure system designed to transfer power with 85.4% efficiency at a 12.5-MHz resonant frequency. The magnetic field at the positions of the cell culture dishes is approximately twice the reference level for occupational exposure as stated in the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. The specific absorption rate at the positions of the cell culture dishes matches the respective reference levels stated in the ICNIRP guidelines. For assessment of genotoxicity, we studied cell growth, cell cycle distribution, DNA strand breaks using the comet assay, micronucleus formation, and hypoxanthine-guanine phosphoribosyltransferase (HPRT) gene mutation, and did not detect any significant effects between the WPT-exposed cells and control cells. Our results suggest that WPT exposure under the conditions of the ICNIRP guidelines does not cause detectable cellular genotoxicity.

  2. Validation of Supervised Automated Algorithm for Fast Quantitative Evaluation of Organ Motion on Magnetic Resonance Imaging

    SciTech Connect

    Prakash, Varuna; Stainsby, Jeffrey A.; Satkunasingham, Janakan; Craig, Tim; Catton, Charles; Chan, Philip; Dawson, Laura; Hensel, Jennifer; Jaffray, David; Milosevic, Michael; Nichol, Alan; Sussman, Marshall S.; Lockwood, Gina; Menard, Cynthia

    2008-07-15

    Purpose: To validate a correlation coefficient template-matching algorithm applied to the supervised automated quantification of abdominal-pelvic organ motion captured on time-resolved magnetic resonance imaging. Methods and Materials: Magnetic resonance images of 21 patients across four anatomic sites were analyzed. Representative anatomic points of interest were chosen as surrogates for organ motion. The point of interest displacements across each image frame relative to baseline were quantified manually and through the use of a template-matching software tool, termed 'Motiontrack.' Automated and manually acquired displacement measures, as well as the standard deviation of intrafraction motion, were compared for each image frame and for each patient. Results: Discrepancies between the automated and manual displacements of {>=}2 mm were uncommon, ranging in frequency of 0-9.7% (liver and prostate, respectively). The standard deviations of intrafraction motion measured with each method correlated highly (r = 0.99). Considerable interpatient variability in organ motion was demonstrated by a wide range of standard deviations in the liver (1.4-7.5 mm), uterus (1.1-8.4 mm), and prostate gland (0.8-2.7 mm). The automated algorithm performed successfully in all patients but 1 and substantially improved efficiency compared with manual quantification techniques (5 min vs. 60-90 min). Conclusion: Supervised automated quantification of organ motion captured on magnetic resonance imaging using a correlation coefficient template-matching algorithm was efficient, accurate, and may play an important role in off-line adaptive approaches to intrafraction motion management.

  3. LUMPED-PARAMETER MODEL ANALYSES OF DATA FROM THE 1992 NEW HOUSE EVALUATION PROJECT - FLORIDA RADON RESEARCH PROGRAM

    EPA Science Inventory

    The report documents analyses of Phase 2 data from the Florida Radon Research Program's New House Evaluation Project (NHEP) that were performed using a lumped-parameter model. The houses evaluated in Phase 2 were monitored by the Florida Solar Energy Center (FSEC) and the Univers...

  4. Evaluation of stress-related anterior lower leg pain with magnetic resonance imaging and intracompartmental pressure measurement.

    PubMed

    Kiuru, Martti J; Mantysaari, Matti J; Pihlajamaki, Harri K; Ahovuo, Juhani A

    2003-01-01

    The purpose of this work was to evaluate stress-related anterior lower leg pain with clinical examination, magnetic resonance imaging, and measurement of anterior tibial compartment pressure findings. All medical data were gathered from 24 conscripts with stress-related anterior lower leg pain. Twenty exhibited bilateral symptoms. In 22 of the 44 cases, the intracompartmental pressure was pathological. Symptoms were exhibited for longer periods by patients with chronic exertional compartment syndrome (CECS) than by other patients (p < 0.01). At rest, magnetic resonance imaging revealed no abnormal findings in the soft tissues of the legs but showed bone abnormalities in 35 symptomatic legs. Thirty-three exhibited bone stress injuries, and two exhibited leg traction periostitis. On magnetic resonance imaging, there was no difference in bone findings between patients with and without CECS (p > 0.05). Stress-related anterior lower leg pain can be related to CECS, bone stress injury, and traction periostitis. Clinical diagnosis is unreliable. CECS and bone stress injury or traction periostitis can occur separately or together.

  5. Functional evaluation of extracardiac ventriculopulmonary conduits and of the right ventricle with magnetic resonance imaging and velocity mapping.

    PubMed

    Holmqvist, C; Oskarsson, G; Ståhlberg, F; Thilén, U; Björkhem, G; Laurin, S

    1999-03-15

    Extracardiac ventriculopulmonary conduits tend to deteriorate over time, developing both obstruction and regurgitation. In this prospective study, magnetic resonance imaging (MRI) was compared with Doppler echocardiography to determine whether MRI improves the noninvasive evaluation of conduit patients. Twenty-five patients (median age 10 years, range 2.5 to 32) were investigated 27 times with Doppler echocardiography and an MRI protocol with spin echo sequences for morphology, velocity mapping, and multislice gradient echo technique for right ventricular volume measuring. Cardiac catheterization data were available in 6 patients. Echocardiography could assess the morphology of the conduits in 6 patients, whereas MRI demonstrated all conduits efficiently. Doppler echocardiography could evaluate the occurrence of regurgitation in 18 patients and could quantify peak velocity in 20 of the patients. A technically adequate MRI velocity mapping was obtained in 25 patients. There was good agreement between MRI and Doppler echocardiography in establishing or not establishing regurgitation, but Doppler echocardiography was less reliable in evaluating the degree of regurgitation. The correlation between peak velocity determined with Doppler and magnetic resonance imaging was r = 0.63 [corrected]. Correlations between catheterization pressure gradients and noninvasive techniques were r = 0.97 for magnetic resonance imaging [corrected] versus catheterization, and r = 0.86 [corrected] for Doppler versus catheterization. MRI can provide complete information on the morphology and function of extracardiac ventriculopulmonary conduits, as well as of the right ventricle. If the results of MRI and echocardiography with Doppler are in agreement, heart catheterization and angiography can be avoided, even in patients considered for conduit replacement.

  6. Optimising magnetic resonance imaging-based evaluation of the ossification of the medial clavicular epiphysis: a multi-centre study.

    PubMed

    Schmidt, S; Henke, C A; Wittschieber, D; Vieth, V; Bajanowski, T; Ramsthaler, F; Püschel, K; Pfeiffer, H; Schmeling, A; Schulz, R

    2016-11-01

    Evaluation of the ossification of the medial clavicular epiphysis plays a key role in forensic age estimation, particularly in determining whether the age of 18 has been attained. A key research objective in the forensic age estimation field at present is to establish non-X-ray methods for investigating the clavicle. This paper looks at the use of magnetic resonance imaging for evaluating the developmental state of the medial clavicular epiphysis. Clavicle specimens obtained from autopsies of 125 female and 270 male subjects aged from 10 to 30 were examined using a 3-T magnetic resonance scanner. One FFE-3D-T1 gradient echo sequence and one 2D-T2 turbo spin echo sequence were acquired. In each case, two investigators undertook a consensual determination of the ossification stage of the medial clavicular epiphysis using recognised classification systems. To determine intra-observer and inter-observer agreement, 80 clavicle specimens were subjected to repeat evaluation. We present statistics relating to the ossification stages. The inclusion of established sub-stages of clavicular ossification offers an additional option for determining whether a subject has attained the age of 18 which is applicable in both sexes. For both sexes, the minimum ages for ossification stages 4 and 5 allow conclusions to be drawn about a subject's age at a point in time lying several years in the past. Magnetic resonance imaging is a valid investigatory procedure for determining the ossification stage of the medial clavicular epiphysis. This paper makes a contribution to expanding the range of methods available for forensic age estimation.

  7. Evaluation of Magnetic Resonance Imaging-Compatible Needles and Interactive Sequences for Musculoskeletal Interventions Using an Open High-Field Magnetic Resonance Imaging Scanner

    SciTech Connect

    Wonneberger, Uta; Schnackenburg, Bernhard; Streitparth, Florian Walter, Thula Rump, Jens Teichgraeber, Ulf K. M.

    2010-04-15

    In this article, we study in vitro evaluation of needle artefacts and image quality for musculoskeletal laser-interventions in an open high-field magnetic resonance imaging (MRI) scanner at 1.0T with vertical field orientation. Five commercially available MRI-compatible puncture needles were assessed based on artefact characteristics in a CuSO4 phantom (0.1%) and in human cadaveric lumbar spines. First, six different interventional sequences were evaluated with varying needle orientation to the main magnetic field B0 (0{sup o} to 90{sup o}) in a sequence test. Artefact width, needle-tip error, and contrast-to-noise ratio (CNR) were calculated. Second, a gradient-echo sequence used for thermometric monitoring was assessed and in varying echo times, artefact width, tip error, and signal-to-noise ratio (SNR) were measured. Artefact width and needle-tip error correlated with needle material, instrument orientation to B0, and sequence type. Fast spin-echo sequences produced the smallest needle artefacts for all needles, except for the carbon fibre needle (width <3.5 mm, tip error <2 mm) at 45{sup o} to B0. Overall, the proton density-weighted spin-echo sequences had the best CNR (CNR{sub Muscle/Needle} >16.8). Concerning the thermometric gradient echo sequence, artefacts remained <5 mm, and the SNR reached its maximum at an echo time of 15 ms. If needle materials and sequences are accordingly combined, guidance and monitoring of musculoskeletal laser interventions may be feasible in a vertical magnetic field at 1.0T.

  8. Potential inert matrix materials: Materials synthesis and evaluation of in-service engineering parameters

    NASA Astrophysics Data System (ADS)

    Xu, Peng

    Containing no fertile materials, inert matrix fuel (IMF) has been introduced as a potential transmutation solution for the increasing inventory of both weapon grade and reactor grade plutonium (Pu). In the present work, the MgO-pyrochlore (Nd2Zr2O7) composites and spinel magnesium stannate (Mg2SnO4) were selected as potential inert matrix (IM) materials. A comprehensive investigation was conducted on evaluation of the engineering parameters of the potential IM materials. The MgO-Nd2Zr2O7 composites and Mg 2SnO4 were fabricated through conventional solid state processing. The crystal structure and microstructure of the synthesized composites and Mg2SnO4 were studied. The irradiation tolerance of the potential IM materials was first assessed. The resistance of Mg2SnO 4 against irradiation induced amorphization was assessed experimentally using in situ TEM technique. The critical amorphization doses for Mg2SnO4 irradiated by 1 MeV Kr2+ ions were determined to be 5.5 dpa at 50 K and 11.0 dpa at 150 K, respectively. The obtained results were compared with other spinels especially MgAl 2O4, and the radiation tolerance of spinels were discussed. The next evaluation was water corrosion resistance of the potential IM materials. Homogeneous MgO-Nd2Zr2O7 composites exhibited an improved hydrothermal corrosion resistance than inhomogeneous composites and pure MgO. Even though spinel Mg2SnO4 was not stable in water at 300°C and saturation pressure, the corrosion was limited only to the surface, and the volume and mass changes were less than 1 % after 720 h corrosion. Feasibility of aqueous reprocessing was evaluated by studying the dissolution behavior of the potential IM materials in acidic solutions, with an emphasis on nitric acid. Dissolution of the MgO-Nd2Zr2O 7 composites in HNO3 resulted in a selective dissolution of MgO. Mechanical agitation such as magnetic bar stirring was necessary to achieve a completed dissolution of MgO and disintegration of porous Nd 2Zr2O7

  9. Evaluation of Parameter Uncertainty Reduction in Groundwater Flow Modeling Using Multiple Environmental Tracers

    NASA Astrophysics Data System (ADS)

    Arnold, B. W.; Gardner, P.

    2013-12-01

    Calibration of groundwater flow models for the purpose of evaluating flow and aquifer heterogeneity typically uses observations of hydraulic head in wells and appropriate boundary conditions. Environmental tracers have a wide variety of decay rates and input signals in recharge, resulting in a potentially broad source of additional information to constrain flow rates and heterogeneity. A numerical study was conducted to evaluate the reduction in uncertainty during model calibration using observations of various environmental tracers and combinations of tracers. A synthetic data set was constructed by simulating steady groundwater flow and transient tracer transport in a high-resolution, 2-D aquifer with heterogeneous permeability and porosity using the PFLOTRAN software code. Data on pressure and tracer concentration were extracted at well locations and then used as observations for automated calibration of a flow and transport model using the pilot point method and the PEST code. Optimization runs were performed to estimate parameter values of permeability at 30 pilot points in the model domain for cases using 42 observations of: 1) pressure, 2) pressure and CFC11 concentrations, 3) pressure and Ar-39 concentrations, and 4) pressure, CFC11, Ar-39, tritium, and He-3 concentrations. Results show significantly lower uncertainty, as indicated by the 95% linear confidence intervals, in permeability values at the pilot points for cases including observations of environmental tracer concentrations. The average linear uncertainty range for permeability at the pilot points using pressure observations alone is 4.6 orders of magnitude, using pressure and CFC11 concentrations is 1.6 orders of magnitude, using pressure and Ar-39 concentrations is 0.9 order of magnitude, and using pressure, CFC11, Ar-39, tritium, and He-3 concentrations is 1.0 order of magnitude. Data on Ar-39 concentrations result in the greatest parameter uncertainty reduction because its half-life of 269

  10. Is there a place for cardiovascular magnetic resonance imaging in the evaluation of cardiovascular involvement in rheumatic diseases?

    PubMed

    Mavrogeni, Sophie; Vassilopoulos, Dimitrios

    2011-12-01

    Cardiovascular magnetic resonance (CMR) is a noninvasive, nonradiating imaging technique, which provides novel information for the evaluation of cardiovascular diseases. Until now it has been successfully used for the evaluation of congenital and acquired heart diseases, cardiac tumors-mass, iron overload, and myocardial fibrosis detection. Recently, its diagnostic capabilities have been extended to the evaluation of myocardial inflammation and myocardial perfusion. Currently, it is considered the gold standard for the evaluation of volumes, mass, ejection fraction of atriums and ventricles, quantification of iron overload in different organs, detection and follow-up of myocardial inflammation, myocardial infarction and its complications, evaluation of the aorta, detection of anomalous coronary arteries, and ectatic or aneurysmatic coronary arteries. All the above applications and mainly the CMR ability to detect myocardial inflammation, perfusion defects, fibrosis, coronary and great arteries aneurysms make it a valuable tool for cardiovascular system assessment, commonly affected during the course of rheumatic diseases. The technique has been already successfully used in the evaluation of vasculitides, systemic lupus erythematosus, myositis, and scleroderma. However, further studies are needed to evaluate its usefulness as a diagnostic and monitoring tool of cardiovascular involvement in rheumatic patients.

  11. Updating Nutritional Data and Evaluation of Technological Parameters of Italian Milk.

    PubMed

    Manzi, Pamela; Di Costanzo, Maria Gabriella; Mattera, Maria

    2013-06-20

    Different technologically treated Italian milks (whole and semi-skimmed ultra-high temperature (UHT), pasteurized and microfiltered milk), collected from 2009 to 2012, were evaluated for nutritional and technological properties. No significant differences in calcium and sodium were detected (p > 0.05), while significant differences were observed concerning phosphorus content, between whole and semi-skimmed milk, and lactose content, between pasteurized and UHT milk (p < 0.05). In UHT milk, lactose isomerization occurred, and lactulose (from 8.6 to 104.0 mg/100 g) was detected. No significant differences (p > 0.05) were detected for choline, a functional molecule, between whole (11.3-14.6 mg/100 g) and semi-skimmed milk (11.1-14.7 mg/100 g), but there were significant differences (p < 0.05) in processing milk (UHT vs. pasteurized milk and UHT vs. microfiltered milk). Among the unsaponifiable compounds, only 13 cis retinol and trans retinol showed differences in technologically treated milk (pasteurized vs. UHT milk and microfiltered vs. UHT milk; p < 0.05). In this research, the greater was the "severity" of milk treatment, the higher was the percent ratio 13 cis/trans retinol (DRI, degree of retinol isomerization). The degree of antioxidant protection parameter (DAP), useful to estimate the potential oxidative stability of fat in foods, was significantly different between whole and semi-skimmed milk (p < 0.05). Finally, the evaluation of color measurement of whole milk showed a good correlation between beta carotene and b* (r = 0.854) and between lactulose and a* (r = 0.862).

  12. Parasitic analysis and π-type Butterworth-Van Dyke model for complementary-metal-oxide-semiconductor Lamb wave resonator with accurate two-port Y-parameter characterizations

    NASA Astrophysics Data System (ADS)

    Wang, Yong; Goh, Wang Ling; Chai, Kevin T.-C.; Mu, Xiaojing; Hong, Yan; Kropelnicki, Piotr; Je, Minkyu

    2016-04-01

    The parasitic effects from electromechanical resonance, coupling, and substrate losses were collected to derive a new two-port equivalent-circuit model for Lamb wave resonators, especially for those fabricated on silicon technology. The proposed model is a hybrid π-type Butterworth-Van Dyke (PiBVD) model that accounts for the above mentioned parasitic effects which are commonly observed in Lamb-wave resonators. It is a combination of interdigital capacitor of both plate capacitance and fringe capacitance, interdigital resistance, Ohmic losses in substrate, and the acoustic motional behavior of typical Modified Butterworth-Van Dyke (MBVD) model. In the case studies presented in this paper using two-port Y-parameters, the PiBVD model fitted significantly better than the typical MBVD model, strengthening the capability on characterizing both magnitude and phase of either Y11 or Y21. The accurate modelling on two-port Y-parameters makes the PiBVD model beneficial in the characterization of Lamb-wave resonators, providing accurate simulation to Lamb-wave resonators and oscillators.

  13. Evaluation of control parameters for Spray-In-Air (SIA) aqueous cleaning for shuttle RSRM hardware

    NASA Technical Reports Server (NTRS)

    Davis, S. J.; Deweese, C. D.

    1995-01-01

    HD-2 grease is deliberately applied to Shuttle Redesigned Solid Rocket Motor (RSRM) D6AC steel hardware parts as a temporary protective coating for storage and shipping. This HD-2 grease is the most common form of surface contamination on RSRM hardware and must be removed prior to subsequent surface treatment. Failure to achieve an acceptable level of cleanliness (HD-2 calcium grease removal) is a common cause of defect incidence. Common failures from ineffective cleaning include poor adhesion of surface coatings, reduced bond performance of structural adhesives, and failure to pass cleanliness inspection standards. The RSRM hardware is currently cleaned and refurbished using methyl chloroform (1,1,1-trichloroethane). This chlorinated solvent is mandated for elimination due to its ozone depleting characteristics. This report describes an experimental study of an aqueous cleaning system (which uses Brulin 815 GD) as a replacement for methyl chloroform. Evaluation of process control parameters for this cleaner are discussed as well as cleaning mechanisms for a spray-in-air process.

  14. A prospective evaluation of obesometric parameters associated with renal stone recurrence

    PubMed Central

    Bos, Derek; Dason, Shawn; Matsumoto, Edward; Pinthus, Jehonathan; Allard, Christopher

    2016-01-01

    Introduction: Our aim was to evaluate whether obesometric serum hormones and body fat distribution are associated with renal stone recurrence. Methods: We conducted a prospective cohort study of participants undergoing renal stone (RS) intervention at a single institution from November 2009–June 2010 and followed them for a median 62 months. Obesometric parameters were measured at baseline, including body mass index (BMI), fasting serum leptin and adiponectin, and proportion of visceral adipose tissue (%VAT) averaged from three fixed axial computed tomography (CT) slices. The primary study outcome was stone recurrence. Results: A total of 110 participants were enrolled. Elevated %VAT was associated RS recurrence; participants with %VAT in the highest quartile had a five-year stone-free rate of 47.1% compared to 72.2% among other participants (p=0.004). Adjusting for gender, elevated %VAT was independently predictive of renal stone recurrence among initial stone formers (n=74; hazard ratio [HR] 4.53, 95% confidence interval [CI] 1.08–19.02), but not among recurrent stone formers (n=19; HR 0.51, 95% CI 0.054–4.72). Other obesometric factors, including leptin, adiponectin, and BMI, were not significantly predictive of recurrence. Conclusions: We report a novel association between an elevated %VAT and stone recurrence. These findings may inform patient counselling and followup regimens. The metabolic basis for these findings requires further investigation. PMID:27878041

  15. Statistical evaluation of hydrobiological parameters of Narmada River water at Hoshangabad City, India.

    PubMed

    Sharma, Shraddha; Dixit, Savita; Jain, Praveen; Shah, K W; Vishwakarma, Rakesh

    2008-08-01

    Narmada is considered to be the lifeline of the state of Madhya Pradesh in Central India. The Narmada water is used for bathing, drinking, irrigation and industrial purposes. The city sewage and industrial effluent from Security paper mill at Hoshangabad drains in the Narmada River and pollutes the water quality. Urban sewage enters into Narmada through main nallas. River water quality at Hoshangabad has become a matter of concern due to continuous changing environment and increasing social and industrial activity that influence the water quality directly or indirectly. The present investigation is undertaken to study the effect of domestic sewage and effluent from Security paper Mill on the water quality and ecology of river Narmada at Hoshangabad. The study is carried on at four sites along with the bank of river Narmada. Water samples from four stations were collected, out of which three main sewage mixing points of the city and one fresh water site are taken into account. The samples collected were analyzed, as per standard methods parameters such as Temperature, pH, were measured in-situ. The statistical evaluations were also made. The result showed increase in BOD, Nitrates, Phosphates and Total Coliforms, No. of phytoplanktons. The results revealed that most of the water samples were below or out of limited; according to the WHO, BIS standards.

  16. Evaluation of control parameters for Spray-In-Air (SIA) aqueous cleaning for shuttle RSRM hardware

    NASA Astrophysics Data System (ADS)

    Davis, S. J.; Deweese, C. D.

    1995-03-01

    HD-2 grease is deliberately applied to Shuttle Redesigned Solid Rocket Motor (RSRM) D6AC steel hardware parts as a temporary protective coating for storage and shipping. This HD-2 grease is the most common form of surface contamination on RSRM hardware and must be removed prior to subsequent surface treatment. Failure to achieve an acceptable level of cleanliness (HD-2 calcium grease removal) is a common cause of defect incidence. Common failures from ineffective cleaning include poor adhesion of surface coatings, reduced bond performance of structural adhesives, and failure to pass cleanliness inspection standards. The RSRM hardware is currently cleaned and refurbished using methyl chloroform (1,1,1-trichloroethane). This chlorinated solvent is mandated for elimination due to its ozone depleting characteristics. This report describes an experimental study of an aqueous cleaning system (which uses Brulin 815 GD) as a replacement for methyl chloroform. Evaluation of process control parameters for this cleaner are discussed as well as cleaning mechanisms for a spray-in-air process.

  17. Low-level laser therapy on skeletal muscle inflammation: evaluation of irradiation parameters

    NASA Astrophysics Data System (ADS)

    Mantineo, Matías; Pinheiro, João P.; Morgado, António M.

    2014-09-01

    We evaluated the effect of different irradiation parameters in low-level laser therapy (LLLT) for treating inflammation induced in the gastrocnemius muscle of rats through cytokines concentration in systemic blood and analysis of muscle tissue. We used continuous (830 and 980 nm) and pulsed illuminations (830 nm). Animals were divided into five groups per wavelength (10, 20, 30, 40, and 50 mW), and a control group. LLLT was applied during 5 days with a constant irradiation time and area. TNF-α, IL-1β, IL-2, and IL-6 cytokines were quantified by ELISA. Inflammatory cells were counted using microscopy. Identical methodology was used with pulsed illumination. Average power (40 mW) and duty cycle were kept constant (80%) at five frequencies (5, 25, 50, 100, and 200 Hz). For continuous irradiation, treatment effects occurred for all doses, with a reduction of TNF-α, IL-1β, and IL-6 cytokines and inflammatory cells. Continuous irradiation at 830 nm was more effective, a result explained by the action spectrum of cytochrome c oxidase (CCO). Best results were obtained for 40 mW, with data suggesting a biphasic dose response. Pulsed wave irradiation was only effective for higher frequencies, a result that might be related to the rate constants of the CCO internal electron transfer process.

  18. A critical evaluation of the relevant parameters for drug redispersion from adhesive mixtures during inhalation.

    PubMed

    de Boer, A H; Dickhoff, B H J; Hagedoorn, P; Gjaltema, D; Goede, J; Lambregts, D; Frijlink, H W

    2005-04-27

    In this paper, the parameters that are relevant to the drug redispersion from adhesive mixtures during inhalation are discussed and evaluated. The results obtained with air classifier technology give strong evidence for a dominating influence of carrier surface properties on the fraction of drug detached during inhalation at a low carrier payload (< or =1%, w/w), versus a dominating effect of carrier bulk properties at higher payloads. Furthermore, the results indicate that there is a fundamental difference between so-called active carrier sites and large surface discontinuities. The difference refers to the saturation concentrations, the rates of saturation and their effects on drug detachment during inhalation. The degree of saturation of the active sites appears to be proportional with the square root of the carrier surface payload (after 10 min mixing time in a Turbula mixer at 90 rpm). The storage volume of the discontinuities seems largely independent of the carrier diameter for particles derived from the same batch of crystalline lactose. Saturation of these discontinuities is completed at a much lower carrier surface payload than saturation of the active sites. Relatively large discontinuities are beneficial to de-agglomeration principles that make use of inertial separation forces during inhalation, as they provide shelter from inertial and frictional press-on forces during mixing which increase the strength of the interparticulate bonds in the powder mixture. For de-agglomeration principles generating frictional, drag or lift forces, carrier surface depressions and projections are disadvantageous however, as they also provide shelter from these removal forces.

  19. Prostate Histotripsy: Evaluation of Prostatic Urethral Treatment Parameters in a Canine Model

    PubMed Central

    Schade, George R.; Styn, Nicholas R.; Ives, Kimberly A.; Hall, Timothy L.; Roberts, William W.

    2013-01-01

    Objective - To assess the impact of histotripsy treatment parameters (pulse number and pulse-repetition frequency [PRF]) on the efficiency of histotripsy induced homogenization of the prostatic urethra. Material and Methods - A total of 34 transabdominal prostate histotripsy treatments were applied along a perpendicular plane traversing the prostatic urethra of 21 canine subjects. - Prostate histotripsy was applied with 1) escalating pulse number with fixed PRF or 2) at fixed pulse number with varying PRFs. - The development of urethral homognization within 14 days of histotripsy was evaluated endoscopically and confirmed histologically. Results - Within 14 days of histotripsy 50%, 83%, 83%, and 100% of subjects receiving 12.5k, 25k, 50k, and 100k pulses per mm of treatment path (delivered at 500Hz PRF), respectively developed prostatic urethral disintegration. - Delivery of 100k pulses per mm was required to achieve urethral disintegration in all subjects within 24 hours of histotripsy treatment. - Increasing histotripsy PRF from 50Hz to 500Hz to 2,000Hz while applying a constant dose of 25k pulses per mm treatment was associated with increased rate of urethral disintegration (50% vs 75% vs 100% at 14 days, respectively). Conclusions - Increasing the number of histotripsy pulses and/or increasing the PRF of histotripsy treatment applied to the urethra may improve the rate and efficiency of prostatic urethral disintegration in the canine model. - This understanding will aid in the development of treatment strategies for prostate histotripsy for BPH in human trials. PMID:24176120

  20. Remote detection of trace effluents using Resonance Raman spectroscopy: Field results and evaluation

    SciTech Connect

    Sedlacek, A.J.; Chen, C.L.

    1995-10-01

    Resonance Raman spectroscopy (RRS) possesses many characteristics that are important for detecting, identifying and monitoring chemical effluents. Raman scattering is a coherent, inelastic, two-photon scattering process where an exciting photon of energy h{nu} promotes a molecule to a virtual level and the subsequently emitted photon is shifted in frequency in accordance with the rotational-vibrational structure of the irradiated species, thereby providing a unique fingerprint of the molecule. Under resonance enhancement, the Raman scattering cross-sections have been observed to increase up to 6 orders of magnitude above the normal scattering cross-sections, thereby providing the practical basis for a remote chemical sensor. Some of the other advantages that a Raman sensor possesses are: (1) very high selectivity (chemical specific fingerprints), (2) independence of the spectral fingerprint on the excitation wavelength (ability to monitor in the solar blind region), (3) chemical mixture fingerprints are the sum of its individual components (no spectral cross-talk), (4) near independence of the Raman fingerprint to its physical state (very similar spectra for gas, liquid, solid or solutions), (5) no absolute calibration is necessary because all Raman signals observed from a given species can be compared with the Raman signal for N{sub 2}, whose concentration is known very accurately, and (6) insensitivity of the Raman signature to environmental conditions (no quenching, or interference from water vapor). In this presentation, the technology of resonance Raman spectroscopy as applied to the detection of narcotics production activities will be presented along with some recent experimental results.

  1. [Magnetic resonance imaging in the evaluation in utero of Siamese twins].

    PubMed

    Cosson, M; Vinatier, D; Patey, P; Maunoury-Lefebvre, C; Bartkowiak, D; Sault, M C; Monnier, J C

    1990-01-01

    The authors report a case of twins conjoined at the umbilicus and diagnosed by ultrasound after 19 weeks of amenorrhoea in whom an assessment in utero was carried out using magnetic resonance imaging after the patient had been curarized. A review of the literature on this very difficult problem of conjoined twins has given us the possibility to assess the diagnostic measures as well as the prognosis of this pathology. In particular we point out the results that can be obtained using MRI in utero during the second and third trimesters of the pregnancy.

  2. NONDESTRUCTIVE EVALUATION OF HYBRID BEARING CERAMIC ROLLERS USING PROCESS COMPENSATED RESONANT TESTING (PCRT)

    SciTech Connect

    Singh, Surendra; Jauriqui, Leanne; Sloan, Trista

    2010-02-22

    We have used Process Compensated Resonant Testing (PCRT) for studying structural integrity and functional performance of ceramic balls used in various auxiliary power units (APUs), propulsion engines, and defense and space missiles. The results show that PCRT is successful in sorting acceptable parts from parts with defects such as micro-structural changes, C-cracks, and scuffs. However, PCRT suffers from limitations, generally not determining the type, size or location of the anomaly. The pursuit of improvements to PCRT is an on-going process.

  3. Magnetic resonance imaging in the evaluation of partial growth arrest after physeal injuries in children.

    PubMed

    Havránek, P; Lízler, J

    1991-09-01

    The precise delineation of the size, shape, and location of an osseous bridge is a critical step in the management of children who have a partial growth arrest of the epiphyseal plate. Five children between the ages of ten and fourteen years were diagnosed, with the aid of conventional roentgenograms, as having a partial growth arrest. Magnetic resonance-imaging studies were carried out to determine the exact size, shape, and location of the osseous bridge. The information derived from the imaging studies was essential for the determination of the appropriate treatment and for the planning and undertaking of any operative intervention.

  4. Estimation of Ecosystem Parameters of the Community Land Model with DREAM: Evaluation of the Potential for Upscaling Net Ecosystem Exchange

    NASA Astrophysics Data System (ADS)

    Hendricks Franssen, H. J.; Post, H.; Vrugt, J. A.; Fox, A. M.; Baatz, R.; Kumbhar, P.; Vereecken, H.

    2015-12-01

    Estimation of net ecosystem exchange (NEE) by land surface models is strongly affected by uncertain ecosystem parameters and initial conditions. A possible approach is the estimation of plant functional type (PFT) specific parameters for sites with measurement data like NEE and application of the parameters at other sites with the same PFT and no measurements. This upscaling strategy was evaluated in this work for sites in Germany and France. Ecosystem parameters and initial conditions were estimated with NEE-time series of one year length, or a time series of only one season. The DREAM(zs) algorithm was used for the estimation of parameters and initial conditions. DREAM(zs) is not limited to Gaussian distributions and can condition to large time series of measurement data simultaneously. DREAM(zs) was used in combination with the Community Land Model (CLM) v4.5. Parameter estimates were evaluated by model predictions at the same site for an independent verification period. In addition, the parameter estimates were evaluated at other, independent sites situated >500km away with the same PFT. The main conclusions are: i) simulations with estimated parameters reproduced better the NEE measurement data in the verification periods, including the annual NEE-sum (23% improvement), annual NEE-cycle and average diurnal NEE course (error reduction by factor 1,6); ii) estimated parameters based on seasonal NEE-data outperformed estimated parameters based on yearly data; iii) in addition, those seasonal parameters were often also significantly different from their yearly equivalents; iv) estimated parameters were significantly different if initial conditions were estimated together with the parameters. We conclude that estimated PFT-specific parameters improve land surface model predictions significantly at independent verification sites and for independent verification periods so that their potential for upscaling is demonstrated. However, simulation results also indicate

  5. [Parameters and paradigms for meta-evaluation: an exploratory and reflective review].

    PubMed

    Furtado, Juarez Pereira; Laperrière, Hélène

    2012-03-01

    The evaluation of an evaluation is not a mere play on words or simply an investigation into the person who evaluates the evaluation. It is far more than that. It is about how to evaluate the diverse components of the evaluation process and the evaluators per se. In this paper, we discuss some promising possibilities for meta-evaluation in the field of evaluation of programs and services. These include fostering interaction between theoretical and practical production in fieldwork and supporting the definition of methods and strategies in a sector imbued with political interests and a profusion of methodological possibilities, and promoting ethical and scientific rigor in the evaluation practices. We conclude this exploratory and reflective review by raising some historical and political questions related to evaluation and meta-evaluation of programs and services and by criticizing the universalist and egalitarian pretensions contained in some evaluation approaches.

  6. Treatment of Locally Advanced Vaginal Cancer With Radiochemotherapy and Magnetic Resonance Image-Guided Adaptive Brachytherapy: Dose-Volume Parameters and First Clinical Results

    SciTech Connect

    Dimopoulos, Johannes C.A.; Schmid, Maximilian P.; Fidarova, Elena; Berger, Daniel; Kirisits, Christian; Poetter, Richard

    2012-04-01

    Purpose: To investigate the clinical feasibility of magnetic resonance image-guided adaptive brachytherapy (IGABT) for patients with locally advanced vaginal cancer and to report treatment outcomes. Methods and Materials: Thirteen patients with vaginal cancer were treated with external beam radiotherapy (45-50.4 Gy) plus IGABT with or without chemotherapy. Distribution of International Federation of Gynecology and Obstetrics stages among patients were as follows: 4 patients had Stage II cancer, 5 patients had Stage III cancer, and 4 patients had Stage IV cancer. The concept of IGABT as developed for cervix cancer was transferred and adapted for vaginal cancer, with corresponding treatment planning and reporting. Doses were converted to the equivalent dose in 2 Gy, applying the linear quadratic model ({alpha}/{beta} = 10 Gy for tumor; {alpha}/{beta} = 3 for organs at risk). Endpoints studied were gross tumor volume (GTV), dose-volume parameters for high-risk clinical target volume (HRCTV), and organs at risk, local control (LC), adverse side effects, and survival. Results: The mean GTV ({+-} 1 standard deviation) at diagnosis was 45.3 ({+-}30) cm{sup 3}, and the mean GTV at brachytherapy was 10 ({+-}14) cm{sup 3}. The mean D90 for the HRCTV was 86 ({+-}13) Gy. The mean D2cc for bladder, urethra, rectum, and sigmoid colon were 80 ({+-}20) Gy, 76 ({+-}16) Gy, 70 ({+-}9) Gy, and 60 ({+-}9) Gy, respectively. After a median follow-up of 43 months (range, 19-87 months), one local recurrence and two distant metastases cases were observed. Actuarial LC and overall survival rates at 3 years were 92% and 85%. One patient with Stage IVA and 1 patient with Stage III disease experienced fistulas (one vesicovaginal, one rectovaginal), and 1 patient developed periurethral necrosis. Conclusions: The concept of IGABT, originally developed for treating cervix cancer, appears to be applicable to vaginal cancer treatment with only minor adaptations. Dose-volume parameters for HRCTV and

  7. Utilizing magnetic resonance imaging logs, openhole logs, and sidewall core analyses to evaluate shaly sands for water-free production

    SciTech Connect

    Taylor, D.A.; Morganti, J.K.; White, H.J. ); Noblett, B.R. )

    1996-01-01

    Nuclear magnetic resonance (NMR) logging using the new C Series Magnetic Resonance Imaging Log (MRIL) system is rapidly enhancing formation evaluation throughout the industry. By measuring irreducible water saturations, permeabilities, and effective porosities, MRIL data can help petrophysicists evaluate low-resistivity pays. In these environments, conventional openhole logs may not define all of the pay intervals. The MRIL system can also reduce the number of unnecessary completions in zones of potentially high water cut. MRIL tool theory and log presentations used with conventional logs and sidewall cores are presented along with field examples. Scanning electron microscope (SEM) analysis shows good correlation of varying grain size in sandstones with the T2 distribution and bulk volume irreducible water determined from the MRIL measurements. Analysis of each new well drilled in the study area shows how water-free production zones were defined. Because the MRIL data were not recorded on one of the wells, predictions from the conventional logs and the MRIL data collected on the other two wells were used to estimate productive zones in the first well. Discussion of additional formation characteristics, completion procedures, actual production, and predicted producibility of the shaly sands is presented. Integrated methodologies resulted in the perforation of 3 new wells for a gross initial potential of 690 BOPD and 0 BWPD.

  8. Utilizing magnetic resonance imaging logs, openhole logs, and sidewall core analyses to evaluate shaly sands for water-free production

    SciTech Connect

    Taylor, D.A.; Morganti, J.K.; White, H.J.; Noblett, B.R.

    1996-12-31

    Nuclear magnetic resonance (NMR) logging using the new C Series Magnetic Resonance Imaging Log (MRIL) system is rapidly enhancing formation evaluation throughout the industry. By measuring irreducible water saturations, permeabilities, and effective porosities, MRIL data can help petrophysicists evaluate low-resistivity pays. In these environments, conventional openhole logs may not define all of the pay intervals. The MRIL system can also reduce the number of unnecessary completions in zones of potentially high water cut. MRIL tool theory and log presentations used with conventional logs and sidewall cores are presented along with field examples. Scanning electron microscope (SEM) analysis shows good correlation of varying grain size in sandstones with the T2 distribution and bulk volume irreducible water determined from the MRIL measurements. Analysis of each new well drilled in the study area shows how water-free production zones were defined. Because the MRIL data were not recorded on one of the wells, predictions from the conventional logs and the MRIL data collected on the other two wells were used to estimate productive zones in the first well. Discussion of additional formation characteristics, completion procedures, actual production, and predicted producibility of the shaly sands is presented. Integrated methodologies resulted in the perforation of 3 new wells for a gross initial potential of 690 BOPD and 0 BWPD.

  9. Magnetic Resonance Spectroscopy for Evaluating Portal-Systemic Encephalopathy in Patients with Chronic Hepatic Schistosomiasis Japonicum

    PubMed Central

    Li, Ying; Mei, Lihong; Qiang, Jinwei; Ju, Shuai; Zhao, Shuhui

    2016-01-01

    Portal-systemic encephalopathy (PSE) is classified as type B hepatic encephalopathy. Portal-systemic shunting rather than liver dysfunction is the main cause of PSE in chronic hepatic schistosomiasis japonicum (HSJ) patients. Owing to lack of detectable evidence of intrinsic liver disease, chronic HSJ patients with PSE are frequently clinically undetected or misdiagnosed, especially chronic HSJ patients with covert PSE (subclinical encephalopathy). In this study, we investigated whether magnetic resonance spectroscopy (MRS) could be a useful tool for diagnosing PSE in chronic HSJ patients. Magnetic resonance (MR) T1-weighted imaging, diffusion-weighted imaging, and MRS were performed in 41 chronic HSJ patients with suspected PSE and in 21 age-matched controls. The T1 signal intensity index (T1SI) and apparent diffusion coefficient (ADC) value were obtained in the Globus pallidus. Liver function was also investigated via serum ammonia and liver function tests. Higher T1SI and ADC values, increased lactate and glutamine levels, and decreased myo-inositol were found in the bilateral Globus pallidus in chronic HSJ patients with PSE. No significantly abnormal serum ammonia or liver function tests were observed in chronic HSJ patients with PSE. On the basis of these findings, we propose a diagnostic procedure for PSE in chronic HSJ patients. This study reveals that MRS can be useful for diagnosing PSE in chronic HSJ patients. PMID:27977668

  10. Magnetic Resonance Spectroscopy for Evaluating Portal-Systemic Encephalopathy in Patients with Chronic Hepatic Schistosomiasis Japonicum.

    PubMed

    Li, Ying; Mei, Lihong; Qiang, Jinwei; Ju, Shuai; Zhao, Shuhui

    2016-12-01

    Portal-systemic encephalopathy (PSE) is classified as type B hepatic encephalopathy. Portal-systemic shunting rather than liver dysfunction is the main cause of PSE in chronic hepatic schistosomiasis japonicum (HSJ) patients. Owing to lack of detectable evidence of intrinsic liver disease, chronic HSJ patients with PSE are frequently clinically undetected or misdiagnosed, especially chronic HSJ patients with covert PSE (subclinical encephalopathy). In this study, we investigated whether magnetic resonance spectroscopy (MRS) could be a useful tool for diagnosing PSE in chronic HSJ patients. Magnetic resonance (MR) T1-weighted imaging, diffusion-weighted imaging, and MRS were performed in 41 chronic HSJ patients with suspected PSE and in 21 age-matched controls. The T1 signal intensity index (T1SI) and apparent diffusion coefficient (ADC) value were obtained in the Globus pallidus. Liver function was also investigated via serum ammonia and liver function tests. Higher T1SI and ADC values, increased lactate and glutamine levels, and decreased myo-inositol were found in the bilateral Globus pallidus in chronic HSJ patients with PSE. No significantly abnormal serum ammonia or liver function tests were observed in chronic HSJ patients with PSE. On the basis of these findings, we propose a diagnostic procedure for PSE in chronic HSJ patients. This study reveals that MRS can be useful for diagnosing PSE in chronic HSJ patients.

  11. Magnetic resonance imaging is superior to radiography in evaluating spinal cord trauma in three bald eagles (Haliaeetus leucocephalus).

    PubMed

    Stauber, Erik; Holmes, Shannon; DeGhetto, Darlene L; Finch, Nickol

    2007-09-01

    Three bald eagles (Haliaeetus leucocephalus) found along highways and unable to fly were presented for evaluation. All eagles exhibited sternal recumbency, as well as flaccid hind limb and tail paralysis. Vertebral column and spinal cord trauma were suspected as the cause. One bird died, whereas the remaining 2 birds were stabilized for diagnostic imaging studies. All 3 birds were evaluated by radiography and magnetic resonance imaging (MRI) for diagnosis and for prognosis in the live birds. Radiographic findings in all 3 birds were inconclusive, whereas MRI results showed extensive damage of the spinal cord and vertebral column, precluding functional recovery. The 2 surviving birds were euthanatized. In all birds, MRI assessments correlated well with necropsy and histopathologic findings.

  12. Global retrieval of ATSR cloud parameters and evaluation (GRAPE): dataset assessment

    NASA Astrophysics Data System (ADS)

    Sayer, A. M.; Poulsen, C. A.; Arnold, C.; Campmany, E.; Dean, S.; Ewen, G. B. L.; Grainger, R. G.; Lawrence, B. N.; Siddans, R.; Thomas, G. E.; Watts, P. D.

    2011-04-01

    The Along-Track Scanning Radiometers (ATSRs) provide a long time-series of measurements suitable for the retrieval of cloud properties. This work evaluates the freely-available Global Retrieval of ATSR Cloud Parameters and Evaluation (GRAPE) dataset (version 3) created from the ATSR-2 (1995-2003) and Advanced ATSR (AATSR; 2002 onwards) records. Users are recommended to consider only retrievals flagged as high-quality, where there is a good consistency between the measurements and the retrieved state (corresponding to about 60% of converged retrievals over sea, and more than 80% over land). Cloud properties are found to be generally free of any significant spurious trends relating to satellite zenith angle. Estimates of the random error on retrieved cloud properties are suggested to be generally appropriate for optically-thick clouds, and up to a factor of two too small for optically-thin cases. The correspondence between ATSR-2 and AATSR cloud properties is high, but a relative calibration difference between the sensors of order 5-10% at 660 nm and 870 nm limits the potential of the current version of the dataset for trend analysis. As ATSR-2 is thought to have the better absolute calibration, the discussion focusses on this portion of the record. Cloud-top heights from GRAPE compare well to ground-based data at four sites, particularly for shallow clouds. Clouds forming in boundary-layer inversions are typically around 1 km too high in GRAPE due to poorly-resolved inversions in the modelled temperature profiles used. Global cloud fields are compared to satellite products derived from the Moderate Resolution Imaging Spectroradiometer (MODIS), Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) measurements, and a climatology of liquid water content derived from satellite microwave radiometers. In all cases the main reasons for differences are linked to differing sensitivity to, and treatment of, multi-layer cloud systems. The correlation coefficient between

  13. Global retrieval of ATSR cloud parameters and evaluation (GRAPE): dataset assessment

    NASA Astrophysics Data System (ADS)

    Sayer, A. M.; Poulsen, C. A.; Arnold, C.; Campmany, E.; Dean, S.; Ewen, G. B. L.; Grainger, R. G.; Lawrence, B. N.; Siddans, R.; Thomas, G. E.; Watts, P. D.

    2010-11-01

    The Along-Track Scanning Radiometers (ATSRs) provide a long time-series of measurements suitable for the retrieval of cloud properties. This work evaluates the freely-available Global Retrieval of ATSR Cloud Parameters and Evaluation (GRAPE) dataset (version 3) created from the ATSR-2 (1995-2003) and Advanced ATSR (AATSR; 2002 onwards) records. Users are recommended to consider only retrievals flagged as high-quality, where there is a good consistency between the measurements and the retrieved state (corresponding to about 60% of converged retrievals over sea, and more than 80% over land). Cloud properties are found to be generally free of any significant spurious trends relating to satellite zenith angle. Estimates of the random error on retrieved cloud properties are suggested to be generally appropriate for optically-thick clouds, and up to a factor of two too small for optically-thin cases. The correspondence between ATSR-2 and AATSR cloud properties is high, but a relative calibration difference between the sensors of order 5-10% at 660 nm and 870 nm limits the potential of the current version of the dataset for trend analysis. As ATSR-2 is thought to have the better absolute calibration, the discussion focusses on this portion of the record. Cloud-top heights from GRAPE compare well to ground-based data at four sites, particularly for shallow clouds. Clouds forming in boundary-layer inversions are typically around 1 km too high in GRAPE due to poorly-resolved inversions in the modelled temperature profiles used. Global cloud fields are compared to satellite products derived from the Moderate Resolution Imaging Spectroradiometer (MODIS), Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) measurements, and a climatology of liquid water content derived from satellite microwave radiometers. In all cases the main reasons for differences are linked to differing sensitivity to, and treatment of, multi-layer cloud systems. The correlation coefficient between

  14. Radiation Pneumonitis After Hypofractionated Radiotherapy: Evaluation of the LQ(L) Model and Different Dose Parameters

    SciTech Connect

    Borst, Gerben R.; Ishikawa, Masayori; Nijkamp, Jasper

    2010-08-01

    Purpose: To evaluate the linear quadratic (LQ) model for hypofractionated radiotherapy within the context of predicting radiation pneumonitis (RP) and to investigate the effect if a linear (L) model in the high region (LQL model) is used. Methods and Materials: The radiation doses used for 128 patients treated with hypofractionated radiotherapy were converted to the equivalent doses given in fractions of 2 Gy for a range of {alpha}/{beta} ratios (1 Gy to infinity) according to the LQ(L) model. For the LQL model, different cut-off values between the LQ model and the linear component were used. The Lyman model parameters were fitted to the events of RP grade 2 or higher to derive the normal tissue complication probability (NTCP). The lung dose was calculated as the mean lung dose and the percentage of lung volume (V) receiving doses higher than a threshold dose of xGy (V{sub x}). Results: The best NTCP fit was found if the mean lung dose, or V{sub x}, was calculated with an {alpha}/{beta} ratio of 3 Gy. The NTCP fit of other {alpha}/{beta} ratios and the LQL model were worse but within the 95% confidence interval of the NTCP fit of the LQ model with an {alpha}/{beta} ratio of 3 Gy. The V{sub 50} NTCP fit was better than the NTCP fit of lower threshold doses. Conclusions: For high fraction doses, the LQ model with an {alpha}/{beta} ratio of 3 Gy was the best method for converting the physical lung dose to predict RP.

  15. Evaluation of total oxidative stress parameters in patients with nasal polyps.

    PubMed

    Bozkus, F; San, I; Ulas, T; Iynen, I; Yesilova, Y; Guler, Y; Aksoy, N

    2013-08-01

    Oxidative stress, an imbalance between reactive oxygen species production and antioxidative defense activity, is believed to have a role in the development and pathogenesis of nasal polyps (NPs). Based on this assumption, several known oxidants and antioxidants have been studied in patients with NPs. The purpose of this study was to evaluate the association between oxidative stress parameters with a more valid and reliable method in patients with NPs. Seventy-three patients with NPs, septal deviations and middle concha hypertrophies were recruited. Patients were divided into two groups; group 1 (n = 38) consisted of patients with NPs, and group 2 (n = 35) included patients with septal deviations and middle concha hypertrophies. Polyp specimens were taken from all patients who underwent endoscopic surgery for NPs. Control specimens were obtained from patients who underwent an operation for septoplasty or middle concha hypertrophy. Blood and tissue samples were obtained to assess total oxidant status (TOS), total antioxidant status (TAS) and oxidative stress index (OSI). Compared to group 2, group 1 had significantly higher TOS and OSI and lower TAS levels both in serum and tissue samples (p < 0.001 for all). In group 1, tissue TOS and OSI levels were significantly higher, and TAS levels were significantly lower than in serum (p < 0.001 for all), whereas no significant difference was found in TOS, OSI and TAS levels either in serum or tissue samples in group 2 (p = 1.0; p = 1; p = 0.208, respectively). In group 1, serum OSI levels were significantly correlated with age (r = 0.442, p = 0.005). Our study demonstrated that oxidative stress, both in serum and tissues in patients with NPs, was higher than in patients without NPs. Our study differs from previous studies in that we used a more reliable method that measures both TOS and TAS.

  16. Evaluation of Sensitivity and Robustness of Geothermal Resource Parameters Using Detailed and Approximate Stratigraphy

    NASA Astrophysics Data System (ADS)

    Whealton, C.; Jordan, T. E.; Frone, Z. S.; Smith, J. D.; Horowitz, F. G.; Stedinger, J. R.

    2015-12-01

    Accurate assessment of the spatial variation of geothermal heat is key to distinguishing among locations for geothermal project development. Resource assessment over large areas can be accelerated by using existing subsurface data collected for other purposes, such as petroleum industry bottom-hole temperature (BHT) datasets. BHT data are notoriously noisy but in many sedimentary basins their abundance offsets the potential low quality of an individual BHT measurement. Analysis requires description of conductivity stratigraphy, which for thousands of wells with BHT values is daunting. For regional assessment, a streamlined method is to approximate the thickness and conductivity of each formation using a set of standard columns rescaled to the sediment thickness at a location. Surface heat flow and related geothermal resource metrics are estimated from these and additional parameters. This study uses Monte Carlo techniques to compare the accuracy and precision of thermal predictions at single locations by the streamlined approach to well-specific conductivity stratigraphy. For 77 wells distributed across the Appalachian Basin of NY, PA, and WV, local geological experts made available detailed information on unit thicknesses . For the streamlined method we used the Correlation of Stratigraphic Units of North America (COSUNA) columns. For both data sets, we described thermal conductivity of the strata using generic values or values from the geologically similar Anadarko Basin. The well-specific surface heat flow and temperature-at-depth were evaluated using a one-dimensional conductive heat flow model. This research addresses the sensitivity of the estimated geothermal output to the model inputs (BHT, thermal conductivity) and the robustness of the approximate stratigraphic column assumptions when estimating the geothermal output. This research was conducted as part of the Dept. of Energy Geothermal Play Fairway Analysis program.

  17. Evaluation of an affinity-amplified immunoassay of graphene oxide using surface plasmon resonance biosensors

    NASA Astrophysics Data System (ADS)

    Chiu, Nan-Fu; Huang, Teng-Yi; Kuo, Chun-Chuan

    2015-05-01

    We describe a fundamental study on the plasmonic properties and advanced biosensing mechanisms of functionalized graphene. We discuss a specific design using modified carboxyl groups, which can modulate surface plasmon (SP) coupling and provide an advantage for their binding to the sensing layer with high-performance affinity in an immunological reaction. The functionalized graphene-based surface plasmon resonance (SPR) biosensors have three advantages: high performance, high sensitivity, and excellent molecular kinetic response. In the future, functionalized graphene sheets will make a unique contribution to photonic and SPR diagnosis devices. We wish to highlight the essential characteristics of functionalized graphene-based SPR biosensors to assist researchers in developing and advancing suitable biosensors for unique applications.

  18. [Evaluation of cardiac tumors by multidetector computed tomography and magnetic resonance imaging].

    PubMed

    Mercado-Guzman, Marcela P; Meléndez-Ramírez, Gabriela; Castillo-Castellon, Francisco; Kimura-Hayama, Eric

    Cardiac tumors, are a rare pathology (0.002-0.3%) in all age groups, however, they have a clinic importance, due the affected organ. They are classified in primary (benign or malignant) and secondary (metastasis) types. Among primary type, mixoma, is the most common benign tumor, and sarcoma represents most of the malignant injuries. Cardiac metastasis are more frequent than primary tumors. Clinic effects of cardiac tumors are unspecific and vary according their location, size and agresivity. The use of Multidetector Computed Tomography (MDCT) and Magnetic Resonance Imaging (MRI) assist on the location, sizing, anatomical relationships and the compromise of adyacents structures, besides, MRI is useful for tissue characterization of the tumor. Due to the previous reasons, studies based on noninvasive cardiovascular imaging, have an important role on the characterization of these lesions and the differential diagnosis among them.

  19. Head trauma evaluated by magnetic resonance and computed tomography: a comparison

    SciTech Connect

    Han, J.G.; Kaufman, B.; Alfidi, R.J.

    1984-01-01

    Magnetic resonance (MR) images and computed tomograms of 25 patients with head trauma were compared. MR proved to be superior in many ways for demonstrating extracerebral as well as intracerebral traumatic lesions. Isodense subdural hemotomas, which present a diagnostic dilemma on CT images were clearly seen on MR, regardless of their varying CT densities. In a case of epidural hematoma, the dura mater was shown directly as nearly devoid of signal on MR. Direct coronal images provided excellent visualization of extracerebral collections along the peritentorial space and subtemporal area. In a patient with intracerebral hematoma CT failed to demonstrate residual parenchymal changes in a 3-month follow-up study, but MR clearly depicted the abnormalities. The superiority of MR over CT was also well illustrated in a patient with post-traumatic osteomyelitis of the calvarium.

  20. Evaluating the Robustness of Graded Response Model and Classical Test Theory Parameter Estimates to Deviant Items.

    ERIC Educational Resources Information Center

    Sinar, Evan F.; Zickar, Michael J.

    2002-01-01

    Examined the influence of deviant scale items on item parameter estimates of focal scale items and person parameter estimates through a comparison of item response theory (IRT) and classical test theory (CTT) models. Used Monte Carlo methods to explore results from a pilot investigation of job attitude data. Discusses implications for researchers…

  1. Using an ensemble smoother to evaluate parameter uncertainty of an integrated hydrological model of Yanqi basin

    NASA Astrophysics Data System (ADS)

    Li, Ning; McLaughlin, Dennis; Kinzelbach, Wolfgang; Li, WenPeng; Dong, XinGuang

    2015-10-01

    Model uncertainty needs to be quantified to provide objective assessments of the reliability of model predictions and of the risk associated with management decisions that rely on these predictions. This is particularly true in water resource studies that depend on model-based assessments of alternative management strategies. In recent decades, Bayesian data assimilation methods have been widely used in hydrology to assess uncertain model parameters and predictions. In this case study, a particular data assimilation algorithm, the Ensemble Smoother with Multiple Data Assimilation (ESMDA) (Emerick and Reynolds, 2012), is used to derive posterior samples of uncertain model parameters and forecasts for a distributed hydrological model of Yanqi basin, China. This model is constructed using MIKESHE/MIKE11software, which provides for coupling between surface and subsurface processes (DHI, 2011a-d). The random samples in the posterior parameter ensemble are obtained by using measurements to update 50 prior parameter samples generated with a Latin Hypercube Sampling (LHS) procedure. The posterior forecast samples are obtained from model runs that use the corresponding posterior parameter samples. Two iterative sample update methods are considered: one based on an a perturbed observation Kalman filter update and one based on a square root Kalman filter update. These alternatives give nearly the same results and converge in only two iterations. The uncertain parameters considered include hydraulic conductivities, drainage and river leakage factors, van Genuchten soil property parameters, and dispersion coefficients. The results show that the uncertainty in many of the parameters is reduced during the smoother updating process, reflecting information obtained from the observations. Some of the parameters are insensitive and do not benefit from measurement information. The correlation coefficients among certain parameters increase in each iteration, although they generally

  2. Evaluation of second-order texture parameters for sea ice classification from radar images

    NASA Astrophysics Data System (ADS)

    Shokr, Mohammed E.

    1991-06-01

    With the advent of airborne and spaceborne synthetic aperture radar (SAR) systems, sea ice classification from SAR images has become an important research subject. Since gray tone alone has proven to be of limited capability in differentiating ice types, texture has naturally become an attractive avenue to explore. Accordingly, performance of texture quantification parameters as related to their ability to discriminate ice types has to be examined. SAR image appearance depends on radar parameters involved in the image construction procedures from the doppler history record. Therefore the feasibility of using universal texture/ice type relationships that hold for all combinations of radar parameters also has to be investigated. To that end, imagery data from three different SAR systems were used in this study. Five conventional texture parameters, derived from the gray level co-occurrence matrix (GLCM), were examined. Two of them were modified to ensure their invariant character under linear gray tone transformations. Results indicated that all parameters were highly correlated. The parameters did not, in general, vary with the computational variables used in generating co-occurrence matrices. Ice types can be identified uniquely by the mean value of any texture parameter. The relatively high variability of texture parameters, however, confuses ice discrimination, particularly of smoother ice types. Ice classification was conducted using a per-pixel maximum likelihood supervised scheme. When texture was combined with gray tone, the overall average classification accuracy was improved. Texture was successful in improving the classification accuracy of multiyear ice but was less promising in discriminating first-season ice types. The best two GLCM texture parameters, according to the computed overall average classification accuracies, were the inverse difference moment and the entropy. A brief description of GLCM texture parameters as related to ice's physical

  3. Biomechanical evaluation of oversized drilling technique on primary implant stability measured by insertion torque and resonance frequency analysis

    PubMed Central

    Santamaría-Arrieta, Gorka; Brizuela-Velasco, Aritza; Fernández-González, Felipe J.; Chávarri-Prado, David; Chento-Valiente, Yelko; Solaberrieta, Eneko; Diéguez-Pereira, Markel; Yurrebaso-Asúa, Jaime

    2016-01-01

    Background This study evaluated the influence of implant site preparation depth on primary stability measured by insertion torque and resonance frequency analysis (RFA). Material and Methods Thirty-two implant sites were prepared in eight veal rib blocks. Sixteen sites were prepared using the conventional drilling sequence recommended by the manufacturer to a working depth of 10mm. The remaining 16 sites were prepared using an oversize drilling technique (overpreparation) to a working depth of 12mm. Bone density was determined using cone beam computerized tomography (CBCT). The implants were placed and primary stability was measured by two methods: insertion torque (Ncm), and RFA (implant stability quotient [ISQ]). Results The highest torque values were achieved by the conventional drilling technique (10mm). The ANOVA test confirmed that there was a significant correlation between torque and drilling depth (p<0.05). However, no statistically significant differences were obtained between ISQ values at 10 or 12 mm drilling depths (p>0.05) at either measurement direction (cortical and medullar). No statistical relation between torque and ISQ values was identified, or between bone density and primary stability (p >0.05). Conclusions Vertical overpreparation of the implant bed will obtain lower insertion torque values, but does not produce statistically significant differences in ISQ values. Key words:Implant stability quotient, overdrilling, primary stability, resonance frequency analysis, torque. PMID:27398182

  4. Magnetic Resonance Spectroscopy and Single-Photon Emission Computed Tomography in the Evaluation of Cerebral Tumors: A Case Report

    PubMed Central

    Siasios, Ioannis; Valotassiou, Varvara; Kapsalaki, Eftychia; Tsougos, Ioannis; Georgoulias, Panagiotis; Fotiadou, Aggeliki; Ioannou, Maria; Koukoulis, Georgios; Dimopoulos, Vassilios; Fountas, Kostas

    2017-01-01

    In their daily clinical practice, physicians have to confront diagnostic dilemmas which cannot be resolved by the application of only one imaging technique. In this case report, we present a 66-year-old woman who was admitted to our institution for the surgical resection of a recently diagnosed brain tumor. The patient had a history of epileptic seizures and was hospitalized in the past for anti-phospholipid syndrome related to a non-Hodgkin lymphoma in remission. Magnetic resonance imaging (MRI) examination revealed an enhancing right parasagittal lesion with significant edema suggestive of a high grade glioma. Advanced MRI techniques including proton magnetic resonance spectroscopy (1H-MRS) showed findings compatible of glioma. An additional examination was performed as part of a protocol that we are routinely performing in our institution for all brain tumors including not only the gold standard advanced MRI techniques but also single-photon emission computed tomography (SPECT) with technetium-99m (Tc99m). Brain SPECT indicated the presence of a meningioma which was verified by the histopathology of the resected specimen. In conclusion, a multimodality approach for the pre-surgical assessment of brain tumors has significant advantages not only for the diagnosis but also for the evaluation of intracranial tumors histology. PMID:27924180

  5. An Evaluation of the Permittivity of Two Different Rock Types Using Microwave Resonator and Waveguide Cutoff Principles

    NASA Astrophysics Data System (ADS)

    Olkkonen, Martta-Kaisa; Eskelinen, Pekka; Huuskonen-Snicker, Eeva; Pellinen, Terhi; Olmos Martinez, Pablo

    2015-01-01

    Methods of measuring the complex permittivity of different rock types are demonstrated in the frequency range from 6 GHz to 17 GHz. The used methods are based on the cylindrical resonator and waveguide cutoff frequency principles. This study is part of a larger research project that aims to characterize the electrical properties of asphalt for road surveying purposes. The studied rock types are metavolcanic rock with intermediate composition and pegmatite. The permittivity values gained with the resonator method are 6.2 for the metavolcanic rock and 4.5 for the pegmatite rock type, whereas the imaginary parts are 0.04 and 0.02. The permittivity values gained with the cutoff frequency method are 6.17 and 4.76 respectively. A reference measurement was made only for the metavolcanic rock in a transmission configuration with two antennas and the permittivity result was 6.21. The three different methods provide consistent permittivity values and are suitable for reliable permittivity evaluation.

  6. Förster resonance energy transfer, absorption and emission spectra in multichromophoric systems. III. Exact stochastic path integral evaluation

    SciTech Connect

    Moix, Jeremy M.; Ma, Jian; Cao, Jianshu

    2015-03-07

    A numerically exact path integral treatment of the absorption and emission spectra of open quantum systems is presented that requires only the straightforward solution of a stochastic differential equation. The approach converges rapidly enabling the calculation of spectra of large excitonic systems across the complete range of system parameters and for arbitrary bath spectral densities. With the numerically exact absorption and emission operators, one can also immediately compute energy transfer rates using the multi-chromophoric Förster resonant energy transfer formalism. Benchmark calculations on the emission spectra of two level systems are presented demonstrating the efficacy of the stochastic approach. This is followed by calculations of the energy transfer rates between two weakly coupled dimer systems as a function of temperature and system-bath coupling strength. It is shown that the recently developed hybrid cumulant expansion (see Paper II) is the only perturbative method capable of generating uniformly reliable energy transfer rates and emission spectra across a broad range of system parameters.

  7. Förster resonance energy transfer, absorption and emission spectra in multichromophoric systems. III. Exact stochastic path integral evaluation.

    PubMed

    Moix, Jeremy M; Ma, Jian; Cao, Jianshu

    2015-03-07

    A numerically exact path integral treatment of the absorption and emission spectra of open quantum systems is presented that requires only the straightforward solution of a stochastic differential equation. The approach converges rapidly enabling the calculation of spectra of large excitonic systems across the complete range of system parameters and for arbitrary bath spectral densities. With the numerically exact absorption and emission operators, one can also immediately compute energy transfer rates using the multi-chromophoric Förster resonant energy transfer formalism. Benchmark calculations on the emission spectra of two level systems are presented demonstrating the efficacy of the stochastic approach. This is followed by calculations of the energy transfer rates between two weakly coupled dimer systems as a function of temperature and system-bath coupling strength. It is shown that the recently developed hybrid cumulant expansion (see Paper II) is the only perturbative method capable of generating uniformly reliable energy transfer rates and emission spectra across a broad range of system parameters.

  8. Ultrasonic evaluation of the Jahn-Teller effect parameters. Application to ZnSe:Cr2 +

    NASA Astrophysics Data System (ADS)

    Gudkov, V. V.; Bersuker, I. B.; Zhevstovskikh, I. V.; Korostelin, Yu V.; Landman, A. I.

    2011-03-01

    A method is constructed that uses ultrasonic experiments to evaluate the parameters of the Jahn-Teller (JT) effect in impurity centers in crystals. The method is based on measurements of temperature dependent attenuation and phase velocity and does not require assumptions about mechanisms of relaxation. The results are illustrated by measurements performed on the impurity system ZnSe:Cr2 + , in which the Cr2 + ion has a threefold degenerate T term in the ground state, subject to the T\\otimes (e+t_2) JT problem. Ultrasound propagation anomalies show that the main JT distortions of the tetrahedral environment of the Cr2 + ion are of tetragonal E type and hence the lowest branch of the adiabatic potential energy surface (APES) is formed in accordance with the T\\otimes e problem. With dopant concentration 3.8 × 1018 cm - 3 the modulus of the constant of linear vibronic coupling to tetragonal E type vibrations is determined by two independent experiments: |FE| = 5.49 × 10 - 5 dyn revealed from attenuation measurements, while a slightly different value |FE| = 5.57 × 10 - 5 dyn emerges from phase velocity measurements. Contributions of other active vibronic modes to the elastic modulus Cl = (C11 + C12 + 2C44)/2 are analyzed and it is shown that the influence of the totally symmetric mode is negligible. Using additional information about this system obtained from independent sources, we also estimated the primary force constant in the E direction (KE≈(1.4-4.2) × 104 dyn cm - 1) and orthorhombic and trigonal saddle points of the APES in the five-dimensional space of the tetragonal and trigonal coordinates, their stabilization energies being EJTO≈81-450 cm - 1 and EJTT≈48-417 cm - 1, respectively (the variations of the KE, EJTO and EJTT values are due to different literature data for EJTE). With these data the APES of the JT linear T\\otimes (e+t_2) problem for the Cr2 + ion in the ZnSe:Cr2 + system is revealed.

  9. Bench-scale evaluation of drinking water treatment parameters on iron particles and water quality.

    PubMed

    Rahman, M Safiur; Gagnon, Graham A

    2014-01-01

    Discoloration of water resulting from suspended iron particles is one of the main customer complaints received by water suppliers. However, understanding of the mechanisms of discoloration as well as role of materials involved in the process is limited. In this study, an array of bench scale experiments were conducted to evaluate the impact of the most common variables (pH, PO4, Cl2 and DOM) on the properties of iron particles and suspensions derived from the oxygenation of Fe(II) ions in NaHCO3 buffered synthetic water systems. The most important factors as well as their rank influencing iron suspension color and turbidity formation were identified for a range of water quality parameters. This was accomplished using a 2(4) full factorial design approach at a 95% confidence level. The statistical analysis revealed that phosphate was found to be the most significant factor to alter color (contribution: 37.9%) and turbidity (contribution: 45.5%) in an iron-water system. A comprehensive study revealed that phosphate and chlorine produced iron suspension with reduced color and turbidity, made ζ-potential more negative, reduced the average particle size, and increased iron suspension stability. In the presence of DOM, color was observed to increase but a reverse trend was observed to decrease the turbidity and to alter particle size distribution. HPSEC results suggest that higher molecular weight fractions of DOM tend to adsorb onto the surfaces of iron particles at early stages, resulting in alteration of the surface charge of iron particles. This in turn limits particles aggregation and makes iron colloids highly stable. In the presence of a phosphate based corrosion inhibitor, this study demonstrated that color and turbidity resulting from suspended iron were lower at a pH value of 6.5 (compared to pH of 8.5). The same trend was observed in presence of DOM. This study also suggested that iron colloid suspension color and turbidity in chlorinated drinking water

  10. Quantitative non-destructive evaluation of composite materials based on ultrasonic parameters

    NASA Technical Reports Server (NTRS)

    Miller, James G.

    1987-01-01

    Research into the nondestructive evaluation of advanced reinforced composite laminates is summarized. The applicability of the Framers-Kronig equations to the nondestructive evaluation of composite materials is described.

  11. Performance evaluation of pitch lap in correcting mid-spatial-frequency errors under different smoothing parameters

    NASA Astrophysics Data System (ADS)

    Xu, Lichao; Wan, Yongjian; Liu, Haitao; Wang, Jia

    2016-10-01

    Smoothing is a convenient and efficient way to restrain middle spatial frequency (MSF) errors. Based on the experience, lap diameter, rotation speed, lap pressure and the hardness of pitch layer are important to correcting MSF errors. Therefore, nine groups of experiments are designed with the orthogonal method to confirm the significance of the above parameters. Based on the Zhang's model, PV (Peak and Valley) and RMS (Root Mean Square) versus processing cycles are analyzed before and after smoothing. At the same time, the smoothing limit and smoothing rate for different parameters to correct MSF errors are analyzed. Combined with the deviation analysis, we distinguish between dominant and subordinate parameters, and find out the optimal combination and law of various parameters, so as to guide the further research and fabrication.

  12. GRS Method for Uncertainties Evaluation of Parameters in a Prospective Fast Reactor

    NASA Astrophysics Data System (ADS)

    Peregudov, A.; Andrianova, O.; Raskach, K.; Tsibulya, A.

    2014-04-01

    A number of recent studies have been devoted to the uncertainty estimation of reactor calculation parameters by the GRS (Generation Random Sampled) method. This method is based on direct sampling input data resulting in formation of random sets of input parameters which are used for multiple calculations. Once these calculations are performed, statistical processing of the calculation results is carried out to determine the mean value and the variance of each calculation parameter of interest. In our study this method is used to estimate the uncertainty of calculation parameters (keff, power density, dose rate) of a prospective sodium-cooled fast reactor. Neutron transport calculations were performed by the nodal diffusion code TRIGEX and Monte Carlo code MMK.

  13. Evaluation of Bioreactor-Cultivated Bone by Magnetic Resonance Microscopy and FTIR Microspectroscopy

    PubMed Central

    Chesnick, Ingrid E.; Avallone, Frank; Leapman, Richard D.; Landis, William J.; Eidelman, Naomi; Potter, Kimberlee

    2007-01-01

    We present a three-dimensional mineralizing model based on a hollow fiber bioreactor (HFBR) inoculated with primary osteoblasts isolated from embryonic chick calvaria. Using non-invasive magnetic resonance microscopy (MRM), the growth and development of the mineralized tissue around the individual fibers were monitored over a period of nine weeks. Spatial maps of the water proton MRM properties of the intact tissue, with 78 μm resolution, were used to determine changes in tissue composition with development. Unique changes in the mineral and collagen content of the tissue were detected with high specificity by proton density (PD) and magnetization transfer ratio (MTR) maps, respectively. At the end of the growth period, the presence of a bone-like tissue was verified by histology and the formation of poorly crystalline apatite was verified by selected area electron diffraction and electron probe X-ray microanalysis. FTIR microspectroscopy confirmed the heterogeneous nature of the bone-like tissue formed. FTIR-derived phosphate maps confirmed that those locations with the lowest PD values contained the most mineral, and FTIR-derived collagen maps confirmed that bright pixels on MTR maps corresponded to regions of high collagen content. In conclusion, the spatial mapping of tissue constituents by FTIR microspectroscopy corroborated the findings of non-invasive MRM measurements and supported the role of MRM in monitoring the bone formation process in vitro. PMID:17174620

  14. Dosimetric evaluation for exposure of patient to a z-gradient coil in magnetic resonance imaging

    SciTech Connect

    Lu Mai; Ueno, Shoogo

    2011-04-01

    In magnetic resonance imaging, time-varied gradient magnetic fields may stimulate nerves and muscles by inducing electric fields and currents in patients, which may potentially cause health problems. In this paper, a realistic z-gradient coil was numerically designed and the exposure level in a 3D real human man model was calculated by using the impedance method. It was found that the z-gradient coil produces a magnetic flux density (B-field) with two regions of good homogeneity along the coil length, separated by a very weak B-field in the middle of the coil. The spatially averaged B-field is 281 times greater than that of the International Commission on Non-Ionizing Radiation Protection's (ICNIRP) reference level. The 1-cm{sup 2}-averaged induced current density in the central nervous system is 87 times greater than that of the ICNIRP's basic restriction. The maximum current density in all of the body tissues is above the nerve stimulation threshold.

  15. Preclinical and clinical evaluation of the liver tumor irreversible electroporation by magnetic resonance imaging

    PubMed Central

    Figini, Matteo; Wang, Xifu; Lyu, Tianchu; Su, Zhanliang; Procissi, Daniele; Yaghmai, Vahid; Larson, Andrew C; Zhang, Zhuoli

    2017-01-01

    Irreversible electroporation (IRE) is a relatively new technique for tumor ablation. It has shown promising results in difficult cases where surgery is not recommended and delicate anatomic structures are present near or within the tumor. Currently, liver cancer is one of the most common targets for IRE treatment. Pre-operative and post-operative imaging has a key role in IRE procedures and research studies. Although ultrasound is usually the first choice, especially for intra-operative guidance, magnetic resonance imaging (MRI) plays an important role in the visualization and characterization of tumor before and after IRE in clinical and preclinical studies. However, the appearance of liver lesions after IRE with different MRI sequences has never been systematically investigated, and the most common practice is to limit the acquisition protocol to only contrast-enhanced T1-weighted images. In this work, the role of MRI in clinical and preclinical assessment of hepatic tumors treated with IRE is reviewed and discussed. PMID:28337285

  16. Flexion strength of the toes in the normal foot. An evaluation using magnetic resonance imaging.

    PubMed

    Green, S M; Briggs, P J

    2013-12-01

    Flexion of the toes may be active from muscle contraction or passive from the reversed windlass function of the plantar aponeurosis. The aim of this study was to estimate the flexion moments the muscles of the foot and long digital flexors may be capable of generating and compare these calculations with published data. Magnetic resonance images were used to measure the maximal cross-sectional area of the foot muscles and long digital flexors, along with the radius of curvature of the metatarsal heads. Using known physiological data the maximal flexion moments the muscles may be able to generate at the metatarsophalangeal (MTP) joints were calculated. The methodology overestimates muscle strength and flexion moments at the metatarsophalangeal joints. The calculated maximal flexion moment at the 1st MTP joint is 4.27-6.84 Nm, for the 2nd, 3rd and 4th MTP joints 3.06-4.91 Nm, and the 5th MTP joint 0.47-0.75 Nm. The flexion moments the muscles may generate at the MTP joints do not account for the flexion forces seen in normal walking. Given that maximal strength is not used in normal walking, we conclude that the reversed windlass mechanism of the plantar aponeurosis must be important in normal function of the toes.

  17. Evaluation of congenital heart disease by cine magnetic resonance imaging (MRI)

    SciTech Connect

    Feiglin, D.H.I.; Moodie, D.S.; O'Donnell, J.K.; Go, R.T.; Sterba, R.; MacIntyre, W.J.

    1985-05-01

    The authors studied 11 adult patients (pts) with atrial septal defect (ASD) and 4 adult pts with ventricular septal defect (VSD) using cine magnetic resonance. All studies were performed using a .6T superconducting magnet with ECG gating and electronic axial rotation when appropriate. Repeated multislice image with no change in physiologic delay of the spin echo pulse sequence, but varying the time by offsetting one slice at each imaging stage allowed for an N x N collection of data where N is the number of slices in one collection set and is equal to the number of sets collected. Algebraic manipulation of the T1 weighted images (TE=30mSec TR

  18. Evaluation of peripheral blood basophil activation by means of surface plasmon resonance imaging.

    PubMed

    Yanase, Yuhki; Hiragun, Takaaki; Yanase, Tetsuji; Kawaguchi, Tomoko; Ishii, Kaori; Hide, Michihiro

    2012-02-15

    Basophil activation in response to antigen may represent specificities of type I allergy of individuals and their reactions in the body. We previously demonstrated that surface plasmon resonance (SPR) sensor could detect the activation of human basophils in response to antigens. In this study, we further developed a technique based on SPR imaging (SPRI) system to detect reactions of individual basophils isolated from human blood, and investigated the potential of this sensor as a tool for diagnosis of type I allergy. To detect the change of refractive index (RI) in individual basophils, human basophils were isolated by negative selection with antibodies conjugated with magnetic beads, fixed on a gold film with anti-basophil antibody and stimulated with various antigens under the measurement of SPRI. The sensor could detect the reactions of individual basophils in response to specific antigens as well as non-specific activators. Moreover, the sensor well allocated two spots of basophils on a sensor chip and detected individual reactions to antigen. Thus, the technique developed in this study can visualize the effect of various stimuli or inhibitors on basophils as change of intracellular RI distribution at the single cell level. In combination with a device to rapidly isolate basophils from peripheral blood, this technique may be a useful tool as a high throughput screening system in clinical diagnosis for type I allergy.

  19. Re-evaluation of biotin-streptavidin conjugation in Förster resonance energy transfer applications

    PubMed Central

    Saremi, Bahar; Wei, Ming-Yuan; Liu, Yuan; Cheng, Bingbing; Yuan, Baohong

    2014-01-01

    Abstract. Bioaffinity conjugation between streptavidin (SA) and biotin has been widely used to link donors and acceptors for investigating the distance-dependent Förster resonance energy transfer (FRET). When studying a commonly used FRET system of (QD-SA)-(biotin-DNA-dye) [donor: quantum dot (QD); acceptor: small organic fluorescent dye; and linker: deoxyribose nucleic acid (DNA) molecule via SA-biotin conjugation], however, a contradictory finding was recently reported in the literature. It was found that the FRET lost its dependence on the number of DNA base pairs when using a phosphate-buffered saline (PBS) solution. We found that the conflicted results were caused by the ionic strength of the adopted buffer solutions. Our results suggest that the dependent FRET on the number of DNA bases is favorable in a low-ionic-strength buffer, whereas in relatively high-ionic-strength buffers, the FRET loses the DNA length dependence. We propose that the independence is mainly caused by the conformational change of DNA molecules from a stretched to a coiled mode when the cations in the high-ionic-strength buffer neutralize the negatively charged backbone of DNA molecules, thereby bringing the acceptors close to the donors. PMID:25162908

  20. Magnetic Resonance Imaging as an Adjunct to Ultrasound in Evaluating Cesarean Scar Ectopic Pregnancy

    PubMed Central

    Wu, Rebecca; Klein, Michelle A.; Mahboob, Sabrina; Gupta, Mala; Katz, Douglas S.

    2013-01-01

    Cesarean scar pregnancies (CSPs) are a relatively rare form of ectopic pregnancy in which the embryo is implanted within the fibrous scar of a previous cesarean section. A greater number of cases of CSPs are currently being reported as the rates of cesarean section are increasing globally and as detection of scar pregnancy has improved with use of transvaginal ultrasound (TVUS) with color Doppler imaging. Delayed diagnosis and management of this potentially life-threatening condition may result in complications, predominantly uterine rupture and hemorrhage with significant potential maternal morbidity. Diagnosis of a cesarean scar pregnancy (CSP) requires a high index of clinical suspicion, as up to 40% of patients may be asymptomatic. TVUS has a reported sensitivity of 84.6% and has become the imaging examination of choice for diagnosis of a CSP. Magnetic resonance imaging (MRI) has been used in a small number of patients as an adjunct to TVUS. In the present report, MRI is highlighted as a problem-solving tool capable of more precisely identifying the relationship of a CSP to adjacent structures, thereby providing additional information critical to directing appropriate patient management and therapy. PMID:23814688

  1. Evaluation of Gastric Volumes: Comparison of 3-D Ultrasound and Magnetic Resonance Imaging.

    PubMed

    Buisman, Wijnand J; Mauritz, Femke A; Westerhuis, Wouter E; Gilja, Odd Helge; van der Zee, David C; van Herwaarden-Lindeboom, Maud Y A

    2016-07-01

    To investigate gastric accommodation, accurate measurements of gastric volumes are necessary. An excellent technique to measure gastric volumes is dynamic magnetic resonance imaging (MRI). Unfortunately, dynamic MRI is expensive and not always available. A new 3-D ultrasound (US) method using a matrix transducer was developed to measure gastric volumes. In this prospective study, 14 healthy volunteers underwent a dynamic MRI and a 3-D US. Gastric volumes were calculated with intra-gastric liquid content and total gastric volume. Mean postprandial liquid gastric content was 397 ± 96.5 mL. Mean volume difference was 1.0 mL with limits of agreement of -8.9 to 10.9 mL. When gastric air was taken into account, mean total gastric volume was 540 ± 115.4 mL SD. Mean volume difference was 2.3 mL with limits of agreement of -21.1 to 26.4 mL. The matrix 3-D US showed excellent agreement with dynamic MRI. Therefore matrix 3-D US is a reliable alternative to measure gastric volumes.

  2. Evaluation of nonlinear impact resonance spectroscopy method for detecting delayed ettringite formation

    NASA Astrophysics Data System (ADS)

    Rashidi, M. M. N.; Paul, A.; Kim, J.-Y.; Jacobs, L. J.; Kurtis, K. E.

    2015-03-01

    The use of the Nonlinear Impact Resonance Acoustic Spectroscopy (NIRAS) method to monitor the evolution of damage due to delayed ettringite formation (DEF) is examined. In practice, the temperature of concrete during casting of precast concrete members or massive concrete structures may reach higher than 70°C which can provide suitable conditions for damage to occur due to DEF, particularly in concrete which is subsequently exposed to wet environments. While expansion - often in excess of 1% - is characteristic of DEF, the evolution of damage begins with microcracking. Unfortunately, there is no standard to test the susceptibility of materials or material combinations to DEF. On the other hand, NIRAS shows great sensitivity to the detection of microcracks and has been successfully applied to concrete to detect thermal and alkali silica reaction in concrete. In this preliminary research, the NIRAS method is used to discriminate among mortar samples which are relatively undamaged and those in the early stages of DEF. The results show that NIRAS could be a reliable and robust method in the detection of microcracks due to DEF.

  3. Evaluation of moving-coil loudspeaker and passive radiator parameters using normal-incidence sound transmission measurements: theoretical developments.

    PubMed

    Leishman, Timothy W; Anderson, Brian E

    2013-07-01

    The parameters of moving-coil loudspeaker drivers are typically determined using direct electrical excitation and measurement. However, as electro-mechano-acoustical devices, their parameters should also follow from suitable mechanical or acoustical evaluations. This paper presents the theory of an acoustical method of excitation and measurement using normal-incidence sound transmission through a baffled driver as a plane-wave tube partition. Analogous circuits enable key parameters to be extracted from measurement results in terms of open and closed-circuit driver conditions. Associated tools are presented that facilitate adjacent field decompositions and derivations of sound transmission coefficients (in terms of driver parameters) directly from the circuits. The paper also clarifies the impact of nonanechoic receiving tube terminations and the specific benefits of downstream field decompositions.

  4. Inversion recovery measurements in the presence of radiation damping and implications for evaluating contrast agents in magnetic resonance.

    PubMed

    Eykyn, Thomas R; Payne, Geoffrey S; Leach, Martin O

    2005-11-21

    Relaxation measurements performed at high magnetic field in magnetic resonance (MR) may be adversely affected by the influence of radiation damping in concentrated samples such as water. We consider how the measured value of T1 is affected by this phenomenon for a gadolinium-doped water sample and for an undoped water sample and consider the implications for evaluating contrast agents. A simple method involving the application of a pulsed field gradient to de-phase residual transverse components of the magnetization is shown to be an effective method for suppressing this effect. Given the central role that measurement of the T1 of water plays in the assessment of contrast agents as well as a host of other MR applications, care should always be employed when measuring and interpreting T1 measurements at high magnetic fields.

  5. Linearized forward and inverse problems of the resonant ultrasound spectroscopy for the evaluation of thin surface layers.

    PubMed

    Růzek, Michal; Sedlák, Petr; Seiner, Hanus; Kruisová, Alena; Landa, Michal

    2010-12-01

    In this paper, linearized approximations of both the forward and the inverse problems of resonant ultrasound spectroscopy for the determination of mechanical properties of thin surface layers are presented. The linear relations between the frequency shifts induced by the deposition of the layer and the in-plane elastic coefficients of the layer are derived and inverted, the applicability range of the obtained linear model is discussed by a comparison with nonlinear models and finite element method (FEM), and an algorithm for the estimation of experimental errors in the inversely determined elastic coefficients is described. In the final part of the paper, the linearized inverse procedure is applied to evaluate elastic coefficients of a 310 nm thick diamond-like carbon layer deposited on a silicon substrate.

  6. Repaired tetralogy of Fallot: the roles of cardiovascular magnetic resonance in evaluating pathophysiology and for pulmonary valve replacement decision support

    PubMed Central

    2011-01-01

    Surgical management of tetralogy of Fallot (TOF) results in anatomic and functional abnormalities in the majority of patients. Although right ventricular volume load due to severe pulmonary regurgitation can be tolerated for many years, there is now evidence that the compensatory mechanisms of the right ventricular myocardium ultimately fail and that if the volume load is not eliminated or reduced by pulmonary valve replacement the dysfunction might be irreversible. Cardiovascular magnetic resonance (CMR) has evolved during the last 2 decades as the reference standard imaging modality to assess the anatomic and functional sequelae in patients with repaired TOF. This article reviews the pathophysiology of chronic right ventricular volume load after TOF repair and the risks and benefits of pulmonary valve replacement. The CMR techniques used to comprehensively evaluate the patient with repaired TOF are reviewed and the role of CMR in supporting clinical decisions regarding pulmonary valve replacement is discussed. PMID:21251297

  7. Resonances and resonance widths

    SciTech Connect

    Collins, T.

    1986-05-01

    Two-dimensional betatron resonances are much more important than their simple one-dimensional counterparts and exhibit a strong dependence on the betatron phase advance per cell. A practical definition of ''width'' is expanded upon in order to display these relations in tables. A primarily pedagogical introduction is given to explain the tables, and also to encourage a wider capability for deriving resonance behavior and wider use of ''designer'' resonances.

  8. Change in resonance parameters of a linear molecule as it bends: Evidence in electron-impact vibrational transitions of hot COS and CO2 molecules*

    NASA Astrophysics Data System (ADS)

    Hoshino, Masamitsu; Ishijima, Yohei; Kato, Hidetoshi; Mogi, Daisuke; Takahashi, Yoshinao; Fukae, Katsuya; Limão-Vieira, Paulo; Tanaka, Hiroshi; Shimamura, Isao

    2016-04-01

    Inelastic and superelastic electron-impact vibrational excitation functions of hot carbonyl sulphide COS (and hot CO2) are measured for electron energies from 0.5 to 3.0 eV (1.5 to 6.0 eV) and at a scattering angle of 90°. Based on the vibrational populations and the principle of detailed balance, these excitation functions are decomposed into contributions from state-to-state vibrational transitions involving up to the second bending overtone (030) in the electronically ground state. Both the 2Π resonance for COS around 1.2 eV and the 2Πu resonance for CO2 around 3.8 eV are shifted to lower energies as the initial vibrational state is excited in the bending mode. The width of the resonance hump for COS changes only little as the molecule bends, whereas that of the overall boomerang resonance for CO2 becomes narrower. The angular distribution of the electrons resonantly scattered by hot COS and hot CO2 is also measured. The different shapes depending on the vibrational transitions and gas temperatures are discussed in terms of the symmetry of the vibrational wave functions. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.

  9. Detection and Evaluation of Early Breast Cancer via Magnetic Resonance Imaging: Studies of Mouse Models and Clinical Implementation

    DTIC Science & Technology

    2007-03-01

    fibrocystic change (FCC), fibroadenoma , papilloma and other. Two-tailed unequal variance Student’s t-tests were performed to evaluate which parameters...lesions ( fibroadenoma , papilloma and FCC). Receiver operating characteristic (ROC) analysis was performed to compare the diagnostic capability of the...studied here. Some typical examples of the modified EMM fits are shown in Fig. 1 for various benign (top row – FCC, fibroadenoma , and papilloma) and

  10. Contribution of magnetic resonance microscopy in the 12-week neurotoxicity evaluation of carbonyl sulfide in Fischer 344 rats.

    PubMed

    Sills, Robert C; Morgan, Daniel L; Herr, David W; Little, Peter B; George, Nneka M; Ton, Thai Vu; Love, Nancy E; Maronpot, Robert R; Johnson, G Allan

    2004-01-01

    In this carbonyl sulfide (COS) study, magnetic resonance microscopy (MRM) and detailed light microscopic evaluation effectively functioned in parallel to assure that the distribution and degree of pathology in the brain was accurately represented. MRM is a powerful imaging modality that allows for excellent identification of neuroanatomical structures coupled with the ability to acquire 200 or more cross-sectional images of the brain, and the ability to display them in multiple planes. F344 rats were exposed to 200-600 ppm COS for up to 12 weeks. Prior to MRM, rats were anesthetized and cardiac perfused with McDowell Trump's fixative containing a gadolinium MR contrast medium. Fixed specimens were scanned at the Duke Center for In Vivo Microscopy on a 9.4 Tesla magnetic resonance system adapted explicitly for microscopic imaging. An advantage of MRM in this study was the ability to identify lesions in rats that appeared clinically normal prior to sacrifice and the opportunity to identify lesions in areas of the brain which would not be included in conventional studies. Other advantages include the ability to examine the brain in multiple planes (transverse, dorsal, sagittal) and obtain and save the MRM images in a digital format that allows for postexperimental data processing and manipulation. MRM images were correlated with neuroanatomical and neuropathological findings. All suspected MRM images were compared to corresponding H&E slides. An important aspect of this study was that MRM was critical in defining our strategy for sectioning the brain, and for designing mechanistic studies (cytochrome oxidase evaluations) and functional assessments (electrophysiology studies) on specifically targeted anatomical sites following COS exposure.

  11. Adalimumab markedly improves enthesitis in patients with psoriatic arthritis: Evaluation with a magnetic resonance imaging scoring system.

    PubMed

    Yanaba, Koichi; Sadaoka, Akari; Yonenaga, Takenori; Saeki, Hidehisa; Umezawa, Yoshinori; Tojo, Shinjiro; Ito, Toshihiro; Kikuchi, Sota; Fukuda, Kunihiko; Nakagawa, Hidemi

    2015-12-01

    Psoriatic arthritis (PsA), a seronegative arthropathy, may often result in progressive joint damage without treatment, leading to disability and impaired quality of life. Early therapeutic intervention of PsA is therefore crucial before the development of irreversible joint damage. Because psoriatic skin lesions generally precede the onset of PsA, dermatologists occupy an important position in treating patients with early PsA. This study aimed to evaluate the efficacy of adalimumab in treating joint disease in patients with PsA, using the PsA magnetic resonance imaging scoring system (PsAMRIS). Five adult Japanese male patients with active PsA were treated with adalimumab. Magnetic resonance imaging was obtained at baseline and 8-32 weeks with 2-3 time points following adalimumab treatment and assessed using PsAMRIS. Adalimumab treatment markedly improved clinical symptoms and disease activities of joint disease, which was confirmed by the reduction of PsAMRIS scores in all patients. Bone marrow edema and periarticular inflammation, reflecting the presence of enthesitis, were dramatically improved at week 8, while improvement of synovitis and flexor tenosynovitis was observed later, at week 24 or 32. However, bone erosion was not improved by adalimumab treatment during the follow-up period. These results indicate that adalimumab treatment is associated with dramatic improvement of enthesitis in patients with PsA, whereas bone erosion may be resistant to such treatment. PsAMRIS appears to be useful for the evaluation of treatment efficacy in PsA.

  12. Reliability measures of functional magnetic resonance imaging in a longitudinal evaluation of mild cognitive impairment.

    PubMed

    Zanto, Theodore P; Pa, Judy; Gazzaley, Adam

    2014-01-01

    As the aging population grows, it has become increasingly important to carefully characterize amnestic mild cognitive impairment (aMCI), a preclinical stage of Alzheimer's disease (AD). Functional magnetic resonance imaging (fMRI) is a valuable tool for monitoring disease progression in selectively vulnerable brain regions associated with AD neuropathology. However, the reliability of fMRI data in longitudinal studies of older adults with aMCI is largely unexplored. To address this, aMCI participants completed two visual working tasks, a Delayed-Recognition task and a One-Back task, on three separate scanning sessions over a three-month period. Test-retest reliability of the fMRI blood oxygen level dependent (BOLD) activity was assessed using an intraclass correlation (ICC) analysis approach. Results indicated that brain regions engaged during the task displayed greater reliability across sessions compared to regions that were not utilized by the task. During task-engagement, differential reliability scores were observed across the brain such that the frontal lobe, medial temporal lobe, and subcortical structures exhibited fair to moderate reliability (ICC=0.3-0.6), while temporal, parietal, and occipital regions exhibited moderate to good reliability (ICC=0.4-0.7). Additionally, reliability across brain regions was more stable when three fMRI sessions were used in the ICC calculation relative to two fMRI sessions. In conclusion, the fMRI BOLD signal is reliable across scanning sessions in this population and thus a useful tool for tracking longitudinal change in observational and interventional studies in aMCI.

  13. Evaluation of apical subtype of hypertrophic cardiomyopathy using cardiac magnetic resonance imaging with gadolinium enhancement.

    PubMed

    Kebed, Kalie Y; Al Adham, Raed I; Bishu, Kalkidan; Askew, J Wells; Klarich, Kyle W; Araoz, Philip A; Foley, Thomas A; Glockner, James F; Nishimura, Rick A; Anavekar, Nandan S

    2014-09-01

    Apical hypertrophic cardiomyopathy (HC) is an uncommon variant of HC. We sought to characterize cardiac magnetic resonance imaging (MRI) findings among apical HC patients. This was a retrospective review of consecutive patients with a diagnosis of apical HC who underwent cardiac MRI examinations at the Mayo Clinic (Rochester, MN) from August 1999 to October 2011. Clinical and demographic data at the time of cardiac MRI study were abstracted. Cardiac MRI study and 2-dimensional echocardiograms performed within 6 months of the cardiac MRI were reviewed; 96 patients with apical HC underwent cardiac MRI examinations. LV end-diastolic and end-systolic volumes were 130.7 ± 39.1 ml and 44.2 ± 20.9 ml, respectively. Maximum LV thickness was 19 ± 5 mm. Hypertrophy extended beyond the apex into other segments in 57 (59.4%) patients. Obstructive physiology was seen in 12 (12.5%) and was more common in the mixed apical phenotype than the pure apical (19.3 vs 2.6%, p = 0.02). Apical pouches were noted in 39 (40.6%) patients. Late gadolinium enhancement (LGE) was present in 70 (74.5%) patients. LGE was associated with severe symptoms and increased maximal LV wall thickness. In conclusion, cardiac MRI is well suited for studying the apical form of HC because of difficulty imaging the cardiac apex with standard echocardiography. Cardiac MRI is uniquely suited to delineate the presence or absence of an apical pouch and abnormal myocardial LGE that may have implications in the natural history of apical HM. In particular, the presence of abnormal LGE is associated with clinical symptoms and increased wall thickness.

  14. Design and evaluation of a detunable water-based quadrature HEM11 mode dielectric resonator as a new type of volume coil for high field MRI.

    PubMed

    Aussenhofer, Sebastian A; Webb, Andrew G

    2012-10-01

    An annular dielectric resonator made from distilled water has been designed to operate in degenerate quadrature HEM11 modes at 298.1 MHz (7 Tesla). The circularly polarized B1+ field has a high degree of homogeneity throughout a sample placed within the annulus. The sensitivity of the resonator was measured to be essentially identical to that of an eight-rung high-pass birdcage resonator with the same physical dimensions. High resolution in vivo images have been obtained from the human wrist. A new method of electronically detuning the resonator has also been evaluated. The design is extremely simple and rapid to build, with direct applicability to very high field imaging and also potential integration into human and animal hybrid position emission tomography (PET)/MRI and single-photon emission computed tomography (SPECT)/MRI systems due to the lack of conductor attenuation-induced artifacts in the reconstructed nuclear medicine images.

  15. Evaluation of a motion artifacts removal approach on breath-hold cine-magnetic resonance images of hypertrophic cardiomyopathy subjects

    NASA Astrophysics Data System (ADS)

    Betancur, Julián.; Simon, Antoine; Schnell, Frédéric; Donal, Erwan; Hernández, Alfredo; Garreau, Mireille

    2013-11-01

    The acquisition of ECG-gated cine magnetic resonance images of the heart is routinely performed in apnea in order to suppress the motion artifacts caused by breathing. However, many factors including the 2D nature of the acquisition and the use of di erent beats to acquire the multiple-view cine images, cause this kind of artifacts to appear. This paper presents the qualitative evaluation of a method aiming to remove motion artifacts in multipleview cine images acquired on patients with hypertrophic cardiomyopathy diagnosis. The approach uses iconic registration to reduce for in-plane artifacts in long-axis-view image stacks and in-plane and out-of-plane motion artifacts in sort-axis-view image stack. Four similarity measures were evaluated: the normalized correlation, the normalized mutual information, the sum of absolute voxel di erences and the Slomka metric proposed by Slomka et al. The qualitative evaluation assessed the misalignment of di erent anatomical structures of the left ventricle as follows: the misalignment of the interventricular septum and the lateral wall for short-axis-view acquisitions and the misalignment between the short-axis-view image and long-axis-view images. Results showed the correction using the normalized correlation as the most appropriated with an 80% of success.

  16. Comparison of computed tomographic angiography and noncontrast magnetic resonance angiography in preoperative evaluation of living renal donors

    PubMed Central

    Patil, Abhijit Dnyandeo; Shailage, K.; Nadarajah, Jeyaseelan; Harigovind, P.; Mohan, R. Krishna

    2017-01-01

    Introduction: The computed tomographic angiography (CTA) renal donor protocol is an established method of preoperative renal vascular pedicle evaluation in prospective renal donors. However, CTA is associated with significant radiation exposure and intravenous contrast administration. The newer noncontrast-enhanced magnetic resonance angiography (NCE-MRA) techniques, especially arterial spin labeling (ASL) with steady-state free precession (SSFP) hold promise as an effective alternative. We prospectively compared CTA with NCE MRA for accuracy in the evaluation of renal arterial anatomy in prospective renal donors. Methods: A total of 43 subjects underwent CTA followed by NCE MRA in a prospective comparative study. The number of renal arteries and early branching of renal arteries were noted in both kidneys in all subjects. Intermodality agreement was calculated using “K” (Kappa) statistics and 95% confidence interval for both modalities. Results: A total of 63 single, 21 double, and 2 triple arteries were detected in 43 subjects on CTA. CTA showed an early branch in 17 kidneys. NCE MRAshowed 64 single arteries, 20 double arteries, and 2 triple arteries. A total of 14 kidneys showed an early branch. Unweighted Kappa statistic of agreement between CTA and NCE MRA for number of renal arteries and for frequency of early branching was 0.9707 and 0.8822, respectively. Conclusions: The newer NCE MRA techniques such as ASL with SSFP among others are potential alternatives for CTA, in the evaluation of prospective renal donors. PMID:28197027

  17. Comparison of intravenous urography and magnetic resonance urography in preoperative evaluation of pelvi-ureteric junction obstruction in children

    PubMed Central

    Sharma, Alok; Sodhi, Kushaljit Singh; Saxena, Akshay Kumar; Bhatia, Anmol; Menon, Prema; Rao, Katragadda L. N.; Khandelwal, Niranjan

    2016-01-01

    Aims: To compare intravenous urography (IVU) and magnetic resonance urography (MRU) in the preoperative evaluation of pelvi-ureteric junction obstruction (PUJO) in children. Materials and Methods: A total of 35 children up to 10 years of age in whom unilateral or bilateral PUJO were suspected on ultrasonography were enrolled in this prospective study. All children underwent IVU and MRU, and the findings were compared. Results: Of the 70 kidneys evaluated, 14 (20%) were not visualized on IVU because of nonexcretion of contrast, whereas all the 70 (100%) kidneys were visualized on MRU. On IVU, nephrogram was not visualized in 66 (94.2%) of the 70 kidneys, whereas MRU showed prompt and homogeneous nephrogram in 68 (97.1%) of the 70 kidneys. No evidence of PUJO was seen in 31 (44.2%) kidneys on both IVU and MRU. IVU showed PUJO in 26 (37.1%) kidneys, whereas MRU showed it in 38 (54.2%) kidneys. MRU detected two duplex systems that were missed on IVU. A focal renal lesion and two incidental extra renal abnormalities were detected on MRU, which were not visualized on IVU. Conclusion: MRU is better than IVU, especially in case of poorly functioning kidneys which are not visualized on IVU. MRU also provides anatomic details of the ureter and vessels with better evaluation of renal parenchyma. It also has an additional advantage of detecting incidental extra renal abnormalities, if present. PMID:27695208

  18. Quantitative evaluation of susceptibility effects caused by dental materials in head magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Strocchi, S.; Ghielmi, M.; Basilico, F.; Macchi, A.; Novario, R.; Ferretti, R.; Binaghi, E.

    2016-03-01

    This work quantitatively evaluates the effects induced by susceptibility characteristics of materials commonly used in dental practice on the quality of head MR images in a clinical 1.5T device. The proposed evaluation procedure measures the image artifacts induced by susceptibility in MR images by providing an index consistent with the global degradation as perceived by the experts. Susceptibility artifacts were evaluated in a near-clinical setup, using a phantom with susceptibility and geometric characteristics similar to that of a human head. We tested different dentist materials, called PAL Keramit, Ti6Al4V-ELI, Keramit NP, ILOR F, Zirconia and used different clinical MR acquisition sequences, such as "classical" SE and fast, gradient, and diffusion sequences. The evaluation is designed as a matching process between reference and artifacts affected images recording the same scene. The extent of the degradation induced by susceptibility is then measured in terms of similarity with the corresponding reference image. The matching process involves a multimodal registration task and the use an adequate similarity index psychophysically validated, based on correlation coefficient. The proposed analyses are integrated within a computer-supported procedure that interactively guides the users in the different phases of the evaluation method. 2-Dimensional and 3-dimensional indexes are used for each material and each acquisition sequence. From these, we drew a ranking of the materials, averaging the results obtained. Zirconia and ILOR F appear to be the best choice from the susceptibility artefacts point of view, followed, in order, by PAL Keramit, Ti6Al4V-ELI and Keramit NP.

  19. Evaluation of some biological tests as parameters for microbial activities in soils. II. Field investigations.

    PubMed

    Abd-El-Malek, Y; Monib, M; Rizk, S G; Shehata, S M

    1976-01-01

    Investigations were designed to study the effect of certain factors on the microbial activities in soil. The parameters, used as an index of the microbial activities, were total bacterial counts, dehydrogenase activity, oxidation of organic carbon, and CO2 evolved/7 days. Bahteem Farm clay soil was examined for determining the effects of depth, type of fertilization, and crop rotation on the microbial activities. It appears that the microbial activities, as indicated by the tested parameters, were more pronounced in the surface 15 cm-layer than in the subsurface layer (15-30 cm). Results of all the parameters tested showed markedly higher increases with farmyard manure than with nitrogenous fertilizer and in the control, without significant differences between the latter two. Moreover, the time of sampling had no effect on the results obtained for all parameters. Different types of rotations did not exert significant variation in total bacterial counts, though more than one crop per year increased the organic carbon content of soil and mostly the dehydrogenase activity, whereas the evolution of CO2 tended to decrease. At Gabal el-Asfar Farm, the effect of irrigation with sewage effluent, for long periods, on the microbial activities of sandy soil was investigated. Sewage water stimulated the total bacteria, raised the dehydrogenase activity, the organic carbon, and the production of CO2. In North El Tahreer and Mariut Sectors, the effect of both the type and age of cultivation on the microbial activities in the calcareous soils were examined. Cultivation raised the figures of all the tested parameters progressively with time of cultivation. It was also noticed that crops exerted more beneficial effects on microbial activities than orchards, and the dehydrogenase test was the most reliable parameter to reveal this fact.

  20. Noise estimation from averaged diffusion weighted images: Can unbiased quantitative decay parameters assist cancer evaluation?

    PubMed Central

    Dikaios, Nikolaos; Punwani, Shonit; Hamy, Valentin; Purpura, Pierpaolo; Rice, Scott; Forster, Martin; Mendes, Ruheena; Taylor, Stuart; Atkinson, David

    2014-01-01

    Purpose Multiexponential decay parameters are estimated from diffusion-weighted-imaging that generally have inherently low signal-to-noise ratio and non-normal noise distributions, especially at high b-values. Conventional nonlinear regression algorithms assume normally distributed noise, introducing bias into the calculated decay parameters and potentially affecting their ability to classify tumors. This study aims to accurately estimate noise of averaged diffusion-weighted-imaging, to correct the noise induced bias, and to assess the effect upon cancer classification. Methods A new adaptation of the median-absolute-deviation technique in the wavelet-domain, using a closed form approximation of convolved probability-distribution-functions, is proposed to estimate noise. Nonlinear regression algorithms that account for the underlying noise (maximum probability) fit the biexponential/stretched exponential decay models to the diffusion-weighted signal. A logistic-regression model was built from the decay parameters to discriminate benign from metastatic neck lymph nodes in 40 patients. Results The adapted median-absolute-deviation method accurately predicted the noise of simulated (R2 = 0.96) and neck diffusion-weighted-imaging (averaged once or four times). Maximum probability recovers the true apparent-diffusion-coefficient of the simulated data better than nonlinear regression (up to 40%), whereas no apparent differences were found for the other decay parameters. Conclusions Perfusion-related parameters were best at cancer classification. Noise-corrected decay parameters did not significantly improve classification for the clinical data set though simulations show benefit for lower signal-to-noise ratio acquisitions. PMID:23913479

  1. Evaluation of Neoadjuvant Chemotherapy Response with Dynamic Contrast Enhanced Breast Magnetic Resonance Imaging in Locally Advanced Invasive Breast Cancer

    PubMed Central

    Gezer, Naciye Sinem; Orbay, Özge; Balcı, Pınar; Durak, Merih Guray; Demirkan, Binnaz; Saydam, Serdar

    2014-01-01

    Objective The reliability of traditional methods such as physical examination, ultrasonography (US) and mammography is limited in determining the type of treatment response in patients with neoadjuvant chemotherapy (NAC) application for locally advanced breast cancer (LABC). Dynamic contrast-enhanced magnetic resonance imaging (MRI) is gaining popularity in the evaluation of NAC response. This study aimed to compare NAC response as determined by dynamic contrast-enhanced breast MRI in patients with LABC to histopathology that is the gold standard; and evaluate the compatibility of MRI, mammography and US with response types. Materials and Methods The US, mammography and MRI findings of 38 patients who received NAC with a diagnosis of locally advanced breast cancer and surgical treatment were retrospectively analyzed and compared to histopathology results. Type of response to treatment was determined according to the “Criteria in Solid Tumors Response Evolution 1.1” by mammography, US and MRI criteria. The relationship between response types as defined by all three imaging modalities and histopathology were evaluated, and the correlation of response type as detected by MRI and pathological response and histopathological type of breast cancer was further determined. For statistical analysis, the chi-square, paired t test, correlation and kappa tests were used. Results There is a statistical moderate positive correlation between response type according to pathology and MRI (kappa: 0.63). There was a weak correlation between response type according to mammography or US and according to pathology (kappa: 0.2). When the distribution of treatment response by MRI is stratified according to histopathological types, partial response was higher in all histopathological types similar to the type of pathologic response. When compared with pathology MRI detected treatment response accurately in 84.2% of the patients. Conclusion Dynamic contrast-enhanced breast MRI appears to

  2. Study of the influence of reference system in surface finishing parameters