Science.gov

Sample records for korrelation zwischen mrt

  1. Minimum resolvable temperature difference (MRT): procedure improvements and dynamic MRT

    NASA Astrophysics Data System (ADS)

    Krapels, Keith; Driggers, Ronald; Vollmerhausen, Richard; Halford, Carl

    2002-02-01

    Minimum resolvable temperature difference (MRT or MRTD) is the primary performance test for tactical military infrared (IR) sensors. It is a lab measurement that may be related to discrimination task performance in the field. Also, a theoretical model exists for deriving the MRT of a particular sensor, where the model is used in sensor design evaluation and trades. The model includes both the human and the sensor/display in the overall system performance and can be considered a visual acuity test of a human looking through the IR imager. Both the model and test are validated for first and second generation forward looking IR sensors. The test procedure has been incorrectly applied to undersampled staring array imagers that are becoming more common today. Additionally, it lacks stringent controllability in the procedures, which hampers test repeatability. As a result, multiple measurements are typically performed and the results averaged. This is usually without regard to statistical requirements for estimating values from distributed data. Improvements to the MRT testing procedure are investigated in this research. Data is reported that supports the use of improved techniques. The first improvement is to standardize the sensor and display configuration procedures. A process for standardization is presented and applied to a mid-wave IR imaging sensor. The currently accepted procedure for the static MRT test is accompanied by errors for undersampled staring array imagers. Thus, the second improvement suggested is to utilize dynamic MRT (DMRT) testing for undersampled IR imaging systems. Two motivations for the study presented here are to minimize the uncertainty associated with MRT testing and to improve the characterization of undersampled imagers. These two goals are achieved by the suggested improvements. The resulting DMRTs are compared with modeled MRTs and static MRTs.

  2. Potential High Resolution Dosimeters For MRT

    NASA Astrophysics Data System (ADS)

    Bräuer-Krisch, E.; Rosenfeld, A.; Lerch, M.; Petasecca, M.; Akselrod, M.; Sykora, J.; Bartz, J.; Ptaszkiewicz, M.; Olko, P.; Berg, A.; Wieland, M.; Doran, S.; Brochard, T.; Kamlowski, A.; Cellere, G.; Paccagnella, A.; Siegbahn, E. A.; Prezado, Y.; Martinez-Rovira, I.; Bravin, A.; Dusseau, L.; Berkvens, P.

    2010-07-01

    Microbeam Radiation Therapy (MRT) uses highly collimated, quasi-parallel arrays of X-ray microbeams of 50-600 keV, produced by 2nd and 3rd generation synchrotron sources, such as the National Synchrotron Light Source (NSLS) in the U.S., and the European Synchrotron Radiation Facility (ESRF) in France, respectively. High dose rates are necessary to deliver therapeutic doses in microscopic volumes, to avoid spreading of the microbeams by cardiosynchronous movement of the tissues. A small beam divergence and a filtered white beam spectrum in the energy range between 30 and 250 keV results in the advantage of steep dose gradients with a sharper penumbra than that produced in conventional radiotherapy. MRT research over the past 20 years has allowed a vast number of results from preclinical trials on different animal models, including mice, rats, piglets and rabbits. Microbeams in the range between 10 and 100 micron width show an unprecedented sparing of normal radiosensitive tissues as well as preferential damage to malignant tumor tissues. Typically, MRT uses arrays of narrow (˜25-100 micron-wide) microplanar beams separated by wider (100-400 microns centre-to-centre, c-t-c) microplanar spaces. We note that thicker microbeams of 0.1-0.68 mm used by investigators at the NSLS are still called microbeams, although some invesigators in the community prefer to call them minibeams. This report, however, limits it discussion to 25-100 μm microbeams. Peak entrance doses of several hundreds of Gy are surprisingly well tolerated by normal tissues. High resolution dosimetry has been developed over the last two decades, but typical dose ranges are adapted to dose delivery in conventional Radiation Therapy (RT). Spatial resolution in the sub-millimetric range has been achieved, which is currently required for quality assurance measurements in Gamma-knife RT. Most typical commercially available detectors are not suitable for MRT applications at a dose rate of 16000 Gy/s, micron

  3. Potential High Resolution Dosimeters For MRT

    SciTech Connect

    Braeuer-Krisch, E.; Brochard, T.; Prezado, Y.; Bravin, A.; Berkvens, P.; Rosenfeld, A.; Lerch, M.; Petasecca, M.; Akselrod, M.; Sykora, J.; Bartz, J.; Ptaszkiewicz, M.; Olko, P.; Berg, A.; Wieland, M.; Doran, S.; Kamlowski, A.; Cellere, G.

    2010-07-23

    Microbeam Radiation Therapy (MRT) uses highly collimated, quasi-parallel arrays of X-ray microbeams of 50-600 keV, produced by 2nd and 3rd generation synchrotron sources, such as the National Synchrotron Light Source (NSLS) in the U.S., and the European Synchrotron Radiation Facility (ESRF) in France, respectively. High dose rates are necessary to deliver therapeutic doses in microscopic volumes, to avoid spreading of the microbeams by cardiosynchronous movement of the tissues. A small beam divergence and a filtered white beam spectrum in the energy range between 30 and 250 keV results in the advantage of steep dose gradients with a sharper penumbra than that produced in conventional radiotherapy. MRT research over the past 20 years has allowed a vast number of results from preclinical trials on different animal models, including mice, rats, piglets and rabbits. Microbeams in the range between 10 and 100 micron width show an unprecedented sparing of normal radiosensitive tissues as well as preferential damage to malignant tumor tissues. Typically, MRT uses arrays of narrow ({approx}25-100 micron-wide) microplanar beams separated by wider (100-400 microns centre-to-centre, c-t-c) microplanar spaces. We note that thicker microbeams of 0.1-0.68 mm used by investigators at the NSLS are still called microbeams, although some invesigators in the community prefer to call them minibeams. This report, however, limits it discussion to 25-100 {mu}m microbeams. Peak entrance doses of several hundreds of Gy are surprisingly well tolerated by normal tissues. High resolution dosimetry has been developed over the last two decades, but typical dose ranges are adapted to dose delivery in conventional Radiation Therapy (RT). Spatial resolution in the sub-millimetric range has been achieved, which is currently required for quality assurance measurements in Gamma-knife RT. Most typical commercially available detectors are not suitable for MRT applications at a dose rate of 16000 Gy

  4. Planar Foil MRT Instability Measurements Using a 1-MA LTD

    NASA Astrophysics Data System (ADS)

    Zier, J. C.; Chalenski, D. A.; Patel, S. G.; French, D. M.; Gilgenbach, R. M.; Gomez, M. R.; Lau, Y. Y.; Steiner, A. M.; Rittersdorf, I. M.; Weis, M. R.; Mazarakis, M. G.; Lopez, M. R.; Cuneo, M. E.

    2011-10-01

    Initial dynamic load experiments were performed on UM's 1-MA linear transformer driver (LTD) facility, MAIZE, to characterize magneto-Rayleigh-Taylor (MRT) instability growth and plasma dynamics on planar-foil plasmas. The loads utilized a double current return plate geometry with a 400 nm-thick Al foil positioned between the return plates. Magnetic pressure accelerated the foil plasma to drive MRT instability that was measured using shadowgraphy. Plasma dynamics were observed to be dominated by an initial expansion phase where both foil interfaces were found to be MRT unstable with 85-105 ns e-folding times. This research was supported by US DoE award number DE-SC0002590, US DoE through SNL award numbers 240985 and 768225 to UM, and from NSF award number PHY 0903340 to UM. JC Zier and SG Patel were supported by NPSC fellowships through SNL.

  5. Validating machine vision MRT performance against trained observer performance for linear shift invariant sensors

    NASA Astrophysics Data System (ADS)

    Burks, Stephen D.; Doe, Joshua M.; Teaney, Brian P.

    2015-05-01

    Researchers at the US Army Night Vision and Electronic Sensors Directorate have added the functionality of Machine Vision MRT (MV-MRT) to the NVLabCap software package. While the original calculations of MV-MRT were compared to human observers performance using digital imagery in a previous effort,1 the technical approach was not tested on 8-bit imagery using a variety of sensors in a variety of gain and level settings. Now that it is more simple to determine the MV-MRT for a sensor in multiple gain settings, it is prudent to compare the results of MV-MRT in multiple gain settings to the performance of human observers for thermal imaging systems that are linear and shift invariant. Here, a comparison of the results for a LWIR system to trained human observers is presented.

  6. The GEANT4 toolkit for microdosimetry calculations: application to microbeam radiation therapy (MRT).

    PubMed

    Spiga, J; Siegbahn, E A; Bräuer-Krisch, E; Randaccio, P; Bravin, A

    2007-11-01

    Theoretical dose distributions for microbeam radiation therapy (MRT) are computed in this paper using the GEANT4 Monte Carlo (MC) simulation toolkit. MRT is an innovative experimental radiotherapy technique carried out using an array of parallel microbeams of synchrotron-wiggler-generated x rays. Although the biological mechanisms underlying the effects of microbeams are still largely unknown, the effectiveness of MRT can be traced back to the natural ability of normal tissues to rapidly repair small damages to the vasculature, and on the lack of a similar healing process in tumoral tissues. Contrary to conventional therapy, in which each beam is at least several millimeters wide, the narrowness of the microbeams allows a rapid regeneration of the blood vessels along the beams' trajectories. For this reason the calculation of the "valley" dose is of crucial importance and the correct use of MC codes for such purposes must be understood. GEANT4 offers, in addition to the standard libraries, a specialized package specifically designed to deal with electromagnetic interactions of particles with matter for energies down to 250 eV. This package implements two different approaches for electron and photon transport, one based on evaluated data libraries, the other adopting analytical models. These features are exploited to cross-check theoretical computations for MRT. The lateral and depth dose profiles are studied for the irradiation of a 20 cm diameter, 20 cm long cylindrical phantom, with cylindrical sources of different size and energy. Microbeam arrays are simulated with the aid of superposition algorithms, and the ratios of peak-to-valley doses are computed for typical cases used in preclinical assays. Dose profiles obtained using the GEANT4 evaluated data libraries and analytical models are compared with simulation results previously obtained using the PENELOPE code. The results show that dose profiles computed with GEANT4's analytical model are almost

  7. Modified recalcification time (MRT): a sensitive cancer test? Review of the evidence.

    PubMed Central

    Spillert, C. R.; Lazaro, E. J.

    1995-01-01

    In the past, hypercoagulability causing cancer-related thrombosis (Trousseau phenomenon) remained unproven for lack of an appropriate coagulation test. This review proves that a modified recalcification time (MRT) test can detect cancer-related hypercoagulability. The hallmark of this test involves incorporating tissue factor (TF) in accurately assessing coagulability. Blood from controls and cancer patients was incubated with saline and endotoxin (to enhance clotting ability by monocyte-generated TF). The MRT with saline incubation (MRTS) and the MRT with endotoxin incubation (MRTE) were determined instrumentally. The MRTE is a more inclusive measure of total TF activity than the MRTS in nonadvanced cancer. The MRTE values (minutes +/- standard deviation) were: controls-5.69 +/- 0.8; miscellaneous cancers-3.17 +/- 1.1; head, neck, and colon cancers-3.9 +/- 0.6; breast cancers-3.6 +/- 0.6; gynecological cancers-4.1 +/- 0.9; and prostate cancers-3.4 +/- 1.1. The MRTE, by demonstrating hypercoagulability in nonadvanced (including occult) cancer, qualifies as a more sensitive marker for cancer than the Trousseau phenomenon. The data suggest that this test may be the most sensitive blood test to detect early cancer. PMID:9583965

  8. SU-C-BRE-04: Microbeam-Radiation-Therapy (MRT): Characterizing a Novel MRT Device Using High Resolution 3D Dosimetry

    SciTech Connect

    Li, Q; Juang, T; Bache, S; Chang, S; Oldham, M

    2014-06-15

    Purpose: The feasibility of MRT has recently been demonstrated utilizing a new technology of Carbon-Nano-Tube(CNT) field emission x-ray sources.This approach can deliver very high dose(10's of Gy) in narrow stripes(sub-mm) of radiation which enables the study of novel radiation treatment approaches. Here we investigate the application of highresolution (50um isotropic) PRESAGE/Optical-CT 3D dosimetry techniques to characterize the radiation delivered in this extremely dosimetrically challenging scenario. Methods: The CNT field emission x-ray source irradiator comprises of a linear cathode array and a novel collimator alignment system. This allows a precise delivery of high-energy small beams up to 160 kVp. A cylindrical dosimeter (∼2.2cm in height ∼2.5cm in diameter) was irradiated by CNT MRT delivering 3 strips of radiation with a nominal entrance dose of 32 Gy.A second dosimeter was irradiated with similar entrance dose, with a regular x-ray irradiator collimated to microscopical strip-beams. 50um (isotropic) 3D dosimetry was performed using an in-house optical-CT system designed and optimized for high resolution imaging (including a stray light deconvolution correction).The percentage depth dose (PDD), peak-to-valley ratio (PVR) and beam width (FWHM) data were obtained and analyzed in both cases. Results: High resolution 3D images were successfully achieved with the prototype system, enabling extraction of PDD and dose profiles. The PDDs for the CNT irradiation showed pronounced attenuation, but less build-up effect than that from the multibeam irradiation. The beam spacing between the three strips has an average value of 0.9mm while that for the 13 strips is 1.5 mm at a depth of 16.5 mm. The stray light corrected image shows line profiles with reduced noise and consistent PVR values. Conclusion: MRT dosimetry is extremely challenging due to the ultra small fields involved.This preliminary application of a novel, ultra-high resolution, optical-CT 3D

  9. Influence of polarization and a source model for dose calculation in MRT

    SciTech Connect

    Bartzsch, Stefan Oelfke, Uwe; Lerch, Michael; Petasecca, Marco; Bräuer-Krisch, Elke

    2014-04-15

    Purpose: Microbeam Radiation Therapy (MRT), an alternative preclinical treatment strategy using spatially modulated synchrotron radiation on a micrometer scale, has the great potential to cure malignant tumors (e.g., brain tumors) while having low side effects on normal tissue. Dose measurement and calculation in MRT is challenging because of the spatial accuracy required and the arising high dose differences. Dose calculation with Monte Carlo simulations is time consuming and their accuracy is still a matter of debate. In particular, the influence of photon polarization has been discussed in the literature. Moreover, it is controversial whether a complete knowledge of phase space trajectories, i.e., the simulation of the machine from the wiggler to the collimator, is necessary in order to accurately calculate the dose. Methods: With Monte Carlo simulations in the Geant4 toolkit, the authors investigate the influence of polarization on the dose distribution and the therapeutically important peak to valley dose ratios (PVDRs). Furthermore, the authors analyze in detail phase space information provided byMartínez-Rovira et al. [“Development and commissioning of a Monte Carlo photon model for the forthcoming clinical trials in microbeam radiation therapy,” Med. Phys. 39(1), 119–131 (2012)] and examine its influence on peak and valley doses. A simple source model is developed using parallel beams and its applicability is shown in a semiadjoint Monte Carlo simulation. Results are compared to measurements and previously published data. Results: Polarization has a significant influence on the scattered dose outside the microbeam field. In the radiation field, however, dose and PVDRs deduced from calculations without polarization and with polarization differ by less than 3%. The authors show that the key consequences from the phase space information for dose calculations are inhomogeneous primary photon flux, partial absorption due to inclined beam incidence outside

  10. A hydrodynamically-consistent MRT lattice Boltzmann model on a 2D rectangular grid

    NASA Astrophysics Data System (ADS)

    Peng, Cheng; Min, Haoda; Guo, Zhaoli; Wang, Lian-Ping

    2016-12-01

    A multiple-relaxation time (MRT) lattice Boltzmann (LB) model on a D2Q9 rectangular grid is designed theoretically and validated numerically in the present work. By introducing stress components into the equilibrium moments, this MRT-LB model restores the isotropy of diffusive momentum transport at the macroscopic level (or in the continuum limit), leading to moment equations that are fully consistent with the Navier-Stokes equations. The model is derived by an inverse design process which is described in detail. Except one moment associated with the energy square, all other eight equilibrium moments can be theoretically and uniquely determined. The model is then carefully validated using both the two-dimensional decaying Taylor-Green vortex flow and lid-driven cavity flow, with different grid aspect ratios. The corresponding results from an earlier model (Bouzidi et al. (2001) [28]) are also presented for comparison. The results of Bouzidi et al.'s model show problems associated with anisotropy of viscosity coefficients, while the present model exhibits full isotropy and is accurate and stable.

  11. Determination of dimensional flow fields in hydrogeological settings via the MRT lattice-Boltzmann method

    NASA Astrophysics Data System (ADS)

    Hilpert, Markus

    2011-09-01

    In this paper we demonstrate how the single and multiple-relaxation-time (MRT) lattice-Boltzmann (LB) method can be used to simulate hydrogeological flows under standard conditions. We explain in detail how real-world hydrogeological flow problems, which are formulated in terms of dimensional boundary and initial conditions, can be related to the nondimensional LB world, in which both the lattice spacing and the time step are nondimensional and typically set to unity. We first demonstrate the method in two examples where analytical solutions are known: steady state and transient flow of water in a square duct where fluid inertia is either negligible or not, respectively. Finally we simulate the flow of water in a sand where inertial forces are not negligible. For steady state flow we also present equations for calculating the permeability. Moreover, we demonstrate and advocate the usage of Richardson's extrapolation, which allows one to estimate LB modeling results for an infinite numerical resolution that include uncertainty intervals. For pressure-driven simulations of steady state creeping flow, we show how one can improve the numerical convergence behavior by performing "light-water" simulations at a lower Reynolds number while still predicting the correct velocity field.

  12. Aorta cross-section calculation and 3D visualization from CT or MRT data using VRML

    NASA Astrophysics Data System (ADS)

    Grabner, Guenther; Modritsch, Robert; Stiegmaier, Wolfgang; Grasser, Simon; Klinger, Thomas

    2005-04-01

    Quantification of vessel diameters of artherosclerotic or congenital stenosis is very important for the diagnosis of vascular diseases. The aorta extraction and cross-section calculation is a software-based application that offers a three-dimensional, platform-independent, colorized visualization of the extracted aorta with augmented reality information of MRT or CT datasets. This project is based on different types of specialized image processing algorithms, dynamical particle filtering and complex mathematical equations. From this three-dimensional model a calculation of minimal cross sections is performed. In user specified distances, the aorta is cut in differently defined directions which are created through vectors with varying length. The extracted aorta and the derived minimal cross-sections are then rendered with the marching cube algorithm and represented together in a three-dimensional virtual reality with a very high degree of immersion. The aim of this study was to develop an imaging software that delivers cardiologists the possibility of (i) furnishing fast vascular diagnosis, (ii) getting precise diameter information, (iii) being able to process exact, local stenosis detection (iv) having permanent data storing and easy access to former datasets, and (v) reliable documentation of results in form of tables and graphical printouts.

  13. Weanling piglet cerebellum: a surrogate for tolerance to MRT (microbeam radiation therapy) in pediatric neuro-oncology

    NASA Astrophysics Data System (ADS)

    Laissue, Jean A.; Blattmann, Hans; Di Michiel, Marco; Slatkin, Daniel N.; Lyubimova, Nadia; Guzman, Raphael; Zimmermann, Werner; Birrer, Stephan; Bley, Tim; Kircher, Patrick; Stettler, Regina; Fatzer, Rosmarie; Jaggy, Andre; Smilowitz, Henry; Brauer, Elke; Bravin, Alberto; Le Duc, Geraldine; Nemoz, Christian; Renier, Michel; Thomlinson, William C.; Stepanek, Jiri; Wagner, Hans-Peter

    2001-12-01

    The cerebellum of the weanling piglet (Yorkshire) was used as a surrogate for the radiosensitive human infant cerebellum in a Swiss-led program of experimental microbeam radiation therapy (MRT) at the ESRF. Five weanlings in a 47 day old litter of seven, and eight weanlings in a 40 day old litter of eleven were irradiated in November, 1999 and June, 2000, respectively. A 1.5 cm-wide x 1.5 xm-high array of equally space approximately equals 20-30 micrometers wide, upright microbeams spaced at 210 micrometers intervals was propagated horizontally, left to right, through the cerebella of the prone, anesthetized piglets. Skin-entrance intra-microbeam peak adsorbed doses were uniform, either 150, 300, 425, or 600 gray (Gy). Peak and inter-microbeam (valley) absorbed doses in the cerebellum were computed with the PSI version of the Monte Carlo code GEANT and benchmarked using Gafchromic and radiochromic film microdosimetry. For approximately equals 66 weeks [first litter; until euthanasia], or approximately equals 57 weeks [second litter; until July 30, 2001] after irradiation, the littermates were developmentally, behaviorally, neurologically and radiologically normal as observed and tested by experienced farmers and veterinary scientists unaware of which piglets were irradiated or sham-irradiated. Morever, MRT implemented at the ESRF with a similar array of microbeams and a uniform skin-entrance peak dose of 625 Gy, followed by immunoprophylaxis, was shown to be palliative or curative in young adult rats bearing intracerebral gliosarcomas. These observations give further credence to MRT's potential as an adjunct therapy for brain tumors in infancy, when seamless therapeutic irradiation of the brain is hazardous.

  14. On Methods for the Analysis of Indefinite Stimuli Perception Characteristics: an fMRT Study of Gender-Specific Differences.

    PubMed

    Fyodorov, A A; Pervushina, O N; Bliznyuk, M V; Khoroshilov, B M; Melnikov, M E; Mazhirina, K G; Stark, M B; Savelov, A A; Petrovsky, E D; Kozlova, L I

    2016-07-01

    Comparative identification of cerebral regions activated in men and women during perception of indefinite images was carried out by fMRT and psychological testing. Nine men and nine women aged 20-26 years took part in the study. The volunteers examined simple geometric figures, slightly structurized images (tables from Rorschach's test), and images of impossible figures. Activation in the cerebellum and visual cortex (bilateral) was more pronounced in women in response to all types of images and less so in the right G. temporalis medius. The right frontal regions (G. precentralis, G. frontalis superior, G. frontalis medius) were also stronger activated in women in response to indefinite stimuli. PMID:27492400

  15. Tanzendes Tier oder exzentrische Positionalität - Philosophische Anthropologie zwischen Darwinismus und Kulturalismus

    NASA Astrophysics Data System (ADS)

    Fischer, Joachim

    Zunächst kurz vorweg zu den Formeln im Titel: "exzentrische Positionalität“ ist der Kategorienvorschlag der Philosophischen Anthropologie (genauer: von Helmuth Plessner) für den Menschen, für seine "Sonderstellung“ unter den Lebewesen - ich werde diesen Begriff erläutern. So viel kann man sagen: Der Terminus ist nicht schwieriger als "Transzendentalität“ oder das "Apriori“ oder "Autopoiesis“, also Begriffe, mit deren Orientierungswert in der intellektuellen Öffentlichkeit bereits gespielt wird, bietet aber möglicherweise mehr Erschließungskraft als die Kunstbegriffe z. B. von Kant, Maturana oder Luhmann. Und "tanzendes Tier“ ist ein glücklicher Anschauungsbegriff, eine Art Übersetzung für "exzentrische Positionalität“ - also ein "verrücktes“ Lebewesen, eine Verrückung im evolutionären Leben, die dieses Lebewesen von Natur aus zu einer bestimmten Art von Lebensführung, nämlich Kultur nötigt. Die Absicht des Beitrages ist es, die Philosophische Anthropologie als eine spezifische Theorietechnik zu präsentieren, um einen adäquaten Begriff des Menschen zu erreichen, und zwar eine Theoriestrategie angesichts des cartesianischen Dualismus - also des Dualismus zwischen Naturalismus und Kulturalismus.

  16. Supraleitung und Interkontinentalraketen „On-line computing“ zwischen Militär, Industrie und Wissenschaft

    NASA Astrophysics Data System (ADS)

    Knolle, Johannes; Joas, Christian

    Der zweite Weltkrieg und der Kalte Krieg veränderten nicht nur das Verhältnis zwischen Militär, Industrie und Wissenschaft, sondern auch die wissenschaftliche Praxis von Physikern und anderen Wissenschaftlern. In den 1950er Jahren stellte die Entwicklung von Interkontinentalraketen die Auftragnehmer des Militärs in der Industrie vor komplexe Fragestellungen, zu deren Lösung sie auf die Expertise von Wissenschaftlern angewiesen waren. Industrieunternehmen gründeten eigene Forschungseinheiten zur Lösung technischer und wissenschaftlicher Probleme.

  17. Completion Report for Multi-Site Incentive MRT 2779 Implement ASC Tripod Initiative by 30SEP08

    SciTech Connect

    East, D; Cerutti, J; Noe, J; Cupps, K; Loncaric, J; Sturtevant, J

    2008-09-22

    This report provides documentation and evidence for the completion of the deployment of the Tripod common operating system (TripodOS, also known as and generally referred to below as TOSS). Background documents for TOSS are provided in Appendices A and B, including the initial TOSS proposal accepted by ASC HQ and Executives in July 2007 and a Governance Model defined by a Tri-Lab working group in September 2007. Appendix C contains a document that clarifies the intent and requirements for the completion criteria associated with MRT 2779. The deployment of TOSS is a Multi-Site Incentive from the ASC FY08-09 Implementation Plan due at the end of Quarter 4 in FY08.

  18. TU-F-BRF-09: Feasibility Study of Spatial and Temporal Fractionation Using a Table-Top Image-Guided MRT System

    SciTech Connect

    Zhang, L; Inscoe, C; Yuan, H; Burk, L; Ger, R; Chtcheprov, P; Lu, J; Chang, S; Zhou, O

    2014-06-15

    Purpose: Microbeam radiation therapy is a promising experimental radiotherapy method for cancer treatment. Synchrotron studies have shown that MRT can preferentially ablate tumors while mostly preserving the surrounding normal tissues. Our purpose is to develop a compact microbeam irradiator that can be accessible for laboratory research on MRT's therapeutic mechanism, with the ultimate goal of translating this technique for clinical applications. Utilizing a carbon nanotube field emission X-ray source array, our lab has developed a first of its kind table-top microbeam irradiator. The purpose of this study is to investigate the possibility of increasing the total dose to the tumor region using spatial and temporal fractionation. Methods: MRI and CT scans were acquired and registered to locate both the target region and the landmark in the treatment coordinate space. A crossbeam treatment configuration was planned to achieve the desired dosage and tumor coverage. One array of 300 μm-thick microbeams was delivered to the target on the first day. Another array, perpendicular to the first one, was delivered the next day targeting the same region. The feasibility of this image-guided MRT procedure was evaluated using a phantom. Gafchromic EBT2 film was employed to characterize the targeting accuracy and the delivered tumor dose. Results: The preliminary phantom study showed that a cross-pattern of microbeam arrays was successfully delivered with sub-millimeter targeting accuracy. The delivered dose in the target region was doubled. The fraction of tumor volume that received the peak dose was increased. Conclusion: Temporal fractionation of crosspatterned microbeams can be delivered to the same target region. The feasibility of this procedure was investigated with a phantom study. Once implemented, this procedure has the potential of increasing the tumor control effect of MRT and of achieving better normal tissue recovery.

  19. Coarse- and fine-grid numerical behavior of MRT/TRT lattice-Boltzmann schemes in regular and random sphere packings

    NASA Astrophysics Data System (ADS)

    Khirevich, Siarhei; Ginzburg, Irina; Tallarek, Ulrich

    2015-01-01

    We analyze the intrinsic impact of free-tunable combinations of the relaxation rates controlling viscosity-independent accuracy of the multiple-relaxation-times (MRT) lattice-Boltzmann models. Preserving all MRT degrees of freedom, we formulate the parametrization conditions which enable the MRT schemes to provide viscosity-independent truncation errors for steady state solutions, and support them with the second- and third-order accurate ("linear" and "parabolic", respectively) boundary schemes. The parabolic schemes demonstrate the advanced accuracy with weak dependency on the relaxation rates, as confirmed by the simulations with the D3Q15 model in three regular arrays (SC, BCC, FCC) of touching spheres. Yet, the low-order, bounce-back boundary rule remains appealing for pore-scale simulations where the precise distance to the boundaries is undetermined. However, the effective accuracy of the bounce-back crucially depends on the free-tunable combinations of the relaxation rates. We find that the combinations of the kinematic viscosity rate with the available "ghost" antisymmetric collision mode rates mainly impact the accuracy of the bounce-back scheme. As the first step, we reduce them to the one combination (presented by so-called "magic" parameter Λ in the frame of the two-relaxation-times (TRT) model), and study its impact on the accuracy of the drag force/permeability computations with the D3Q19 velocity set in two different, dense, random packings of 8000 spheres each. We also run the simulations in the regular (BCC and FCC) packings of the same porosity for the broad range of the discretization resolutions, ranging from 5 to 750 lattice nodes per sphere diameter. A special attention is given to the discretization procedure resulting in significantly reduced scatter of the data obtained at low resolutions. The results reveal the identical Λ-dependency versus the discretization resolution in all four packings, regular and random. While very small

  20. Pore-scale simulation of fluid flow passing over a porously covered square cylinder located at the middle of a channel, using a hybrid MRT-LBM-FVM approach

    NASA Astrophysics Data System (ADS)

    Salimi, Mohammad Reza; Taeibi Rahni, Mohammad; Jam, Freydun

    2015-06-01

    A comprehensive study was performed to analyze the unsteady laminar flow characteristics around a porously covered, a fully porous, and a solid squared section cylinder located in the middle of a plane channel. In order to simulate fluid flow inside porous media and porous-fluid interface accurately (minimizing modeling error), the porous region was analyzed in pore scale, using LBM. Additionally, to minimize the LBM-related compressibility error through the porous region, a multi-block multiple relaxation time lattice Boltzmann method (MRT-LBM) was used. Also, to decrease CPU time, a Navier-Stokes flow solver, based on finite volume method and SIMPLE algorithm, was coupled with MRT-LBM to simulate flow around the porous obstacle. It should be noted that the flow inside the porous layer is in continuum regime, and hence, the no-slip boundary condition was used to treat the solid walls inside the porous media. In our simulations, we considered variations of porosity and Reynolds number ranging from 0.75 to 0.94 and from 60 to 240, respectively. The effects of porosity and Reynolds number on vortex pattern, mean drag coefficient, amplitude of lift coefficient, and Strouhal number were investigated. Comparison of our results with the ones obtained using Open FOAM, as well as published by others, shows the suitable accuracy of our computations. It is seen that at low Reynolds numbers or at low porosities, where the mean flow does not have large enough momentum to penetrate porous media, the resulting flow field and aerodynamic coefficients are relatively close for three different configurations used. However, as the flow Reynolds number or permeability increases, the mean flow penetrates easier into the porous media and thus provides different shedding characteristics and aerodynamic coefficients for different obstacle shapes.

  1. Quantenexperimente zwischen Photon und Fulleren

    NASA Astrophysics Data System (ADS)

    Zeilinger, Anton

    2000-09-01

    Die Quantenphysik hat zu Beginn des zwanzigsten Jahrhunderts unser Weltbild revolutioniert. Jetzt scheint sie sich zur Grundlage einer völlig neuen Informationstechnolgie mit unabsehbaren Folgen zu entwickeln.

  2. Introduction and Mission Response Team (MRT)

    NASA Technical Reports Server (NTRS)

    Pool, Sam

    2005-01-01

    On February 1, 2003 the Space Shuttle Columbia, returning to Earth with a crew of seven astronauts, disintegrated along a track extending from California to Louisiana. Observers on the ground filmed breakup of the spacecraft. Debris fell along a 567 statute mile track from Littlefield, Texas to Fort Polk, Louisiana; the largest ever recorded debris field. At the time of the accident the National Aeronautics and Space Administration (NASA) flight surgeon on-duty at the Mission Control Center (MCC) in Houston, Texas initiated the medical contingency response. The DOD surgeon at Patrick Air Force Base was notified, NASA medical personnel were recalled and the services of Armed Forces Institute of Pathology (AFIP) were requested. Subsequent to the accident the NASA flight surgeons that had supported the crew on orbit now provided medical support to the crewmember s families. Federal Emergency Management Agency (FEMA), the National Transportation Safety Board (NTSB), the Federal Bureau of Investigation (FBI) and numerous other federal, state and local agencies along with the citizens of Texas and Louisiana responded to the disaster. Search and recovery was managed from a Disaster Field Office (DFO) established in Lufkin, Texas. Mishap Investigation Team (MIT) medical operations were managed from Barksdale Air Force Base, Louisiana. Accident investigation teams (Columbia Accident Investigation Task Force (CAITF) and Columbia Accident Investigation Board (CAIB)) appointed immediately after the disaster included current and former authorities in space medicine. In August 2003, the CAIB concluded its investigation and released its findings in a report published in February 2004.

  3. MRT fuel element inspection at Dounreay

    SciTech Connect

    Gibson, J.

    1997-08-01

    To ensure that their production and inspection processes are performed in an acceptable manner, ie. auditable and traceable, the MTR Fuel Element Fabrication Plant at Dounreay operates to a documented quality system. This quality system, together with the fuel element manufacturing and inspection operations, has been independently certified to ISO9002-1987, EN29002-1987 and BS5750:Pt2:1987 by Lloyd`s Register Quality Assurance Limited (LRQA). This certification also provides dual accreditation to the relevant German, Dutch and Australian certification bodies. This paper briefly describes the quality system, together with the various inspection stages involved in the manufacture of MTR fuel elements at Dounreay.

  4. More great saphenous vein valves - less varicose veins?

    PubMed

    Gräub, Anna-Barbara; Naef, Markus; Wagner, Hans E; Mouton, Wolfgang G

    2014-07-01

    Hintergrund: Die Bedeutung der Anzahl der Venenklappen und derer degenerativen Veränderungen sind bei der Krampfadererkrankungen weder umfassend dokumentiert noch erforscht. Ziel dieser prospektiven Studie ist die quantitative und qualitative Erfassung und Beschreibung der Venenklappen bei Venenerkrankungen der CEAP Stadien C2 bis C6. Patienten und Methoden: Innerhalb von zwei Jahren wurden 152 Patienten (entsprechend 223 Beinen) mit Primäroperation der Vena saphena magna in die Studie eingeschlossen. Bei allen Patienten wurde das CEAP Stadium präoperativ für jedes Bein bestimmt (C2 bis C6). Die Klappen wurden nach der Entfernung der Vena saphena magna quantitativ und qualitativ erfasst. Die qualitative Erfassung erfolgte makroskopisch mittels sechs Klappenerkrankungsklassen (0 bis 5). Ergebnisse: Es bestand eine negative Korrelation zwischen dem Patientenalter und der Anzahl der Klappen (p = 0.0035). Die C-Klasse der CEAP-Einteilung stieg mit zunehmendem Patientenalter. Es fand sich keine statistisch signifikante Korrelation zwischen der Anzahl der Klappen pro Meter und der C-Klasse der CEAP-Einteilung. Bei allen CEAP-Klassen wurden zwischen vier und fünf Klappen pro Meter gezählt. Die Klappenerkrankungsklasse war positiv zur CEAP-Klasse korreliert, wenn auch die Klappenerkrankungsklasse die CEAP-Klasse nie überschritt (p < 0.05). Schlussfolgerungen: Die Venenklappenklasse korreliert in unserer Studie mit der klinischen CEAP-Klasse; die Anzahl der Klappen korreliert nicht mit der klinischen CEAP-Klasse.

  5. MRT letter: visual attention driven framework for hysteroscopy video abstraction.

    PubMed

    Ejaz, Naveed; Mehmood, Irfan; Baik, Sung Wook

    2013-06-01

    Diagnostic hysteroscopy is a popular method for investigating the regions in the female reproductive system. The videos generated by hysteroscopy sessions of patients are recurrently archived in medical libraries. Gynecologists often need to browse these libraries in search of similar cases or for reviewing old videos of a patient. Diagnostic hysteroscopy videos contain a lot of information with abundant redundancy. Key frame extraction-based video summarization can be used to reduce this huge amount of data. Moreover, key frames can be used for browsing and indexing of hysteroscopy videos. In this article, a domain specific visual attention driven framework for summarization of hysteroscopy videos is proposed. The visual attention model is materialized by computing saliency based on color, texture, and motion. The experimental results, in comparison with other techniques, demonstrate the efficacy of the proposed framework.

  6. [Magnetic resonance tomography (MRT) of the breast in problem patients].

    PubMed

    Brezina, A; Schwaighofer, B W

    1994-01-01

    Over the past few years MRI has become important in the evaluation of inconclusive mammograms. These studies were performed on high-field strength machines, which have the disadvantage of limited accessibility. We evaluated 185 investigations on 169 patients on a 0.5 Tesla MR machine using a dynamic sequence and gadolinium (Gd) DTPA. The results in 107 patients were correlated with the histological findings and MRI assessment proved correct in 44 of 47 benign lesions (93.6%) and 57 of 60 malignant lesions (95%). The 3 false positive results occurred in patients with mastitis, fibroadenoma and an ectatic vessel, respectively. Of the 3 false negative results 2 occurred in patients with microcarcinomas and were due to partial-volume artefacts, whilst the third was due to a technical error. These results compare with those reported in the literature using mainly high-field strength machines. Furthermore, unsuspected second tumours were diagnosed in the ipsilateral breast of 6 women and infiltration of the adjacent thoracic wall in 4 women, findings which had not been evident on mammography. Hence, our results indicate that a mild-field strength MR machine is a valuable tool not only for the non-invasive differentiation between benign and malignant lesions of the breast, but also for planning therapeutic strategy. PMID:7992497

  7. Black Hawk Down: Film Zwischen Reflektion und Konstruktion Gesellschaftlicher Wirklichkeit

    NASA Astrophysics Data System (ADS)

    Pötzsch, Holger

    2009-05-01

    BLACK HAWK DOWN: FILM BETWEEN THE REFLECTION AND CONSTRUCTION OF SOCIAL REALITY - In this article, Ridley Scott's film Black Hawk Down (USA 2001) is read in the context of contemporary theories concerning cultural memory (Jan and Aleida Assmann) and media culture (Douglas Kellner). It is argued that film (and representation in general) does not merely reflect a preceding reality; it also actively serves to construct it. It is shown how Scott's film privileges one particular perspective on an actual event and how this point of view is objectified and installed in the memory of Western media culture. What potential implications does an increased blurring of fact and fiction in the representation of war have? What are the consequences for political and pedagogical practice? What role can cultural studies play in these processes?

  8. Vom Urknall zum Zerfall. Die Welt zwischen Anfang und Ende.

    NASA Astrophysics Data System (ADS)

    Fritzsch, H.

    Contents: Der Tanz mit dem Ozean. Galaktische Landkarte. Das Maß der Dinge. Der würfelnde Gott der Quantenphysik. Geheimnisvolle Felder. Materie und Antimaterie. Quarks - Urstoff unserer Welt. Zerfallende Protonen und die Einheit der Physik. Der Zauberofen. Das überschaubare Universum. Das explodierende Universum. Nachhall der Schöpfung. Der achtfache Weg der kosmischen Entwicklung. Das Ende der Welt. Einheit in der Vielfalt. Das geistige Universum. Gott und das absurde Universum.

  9. MRT letter: Micro- to nanoscale sample collection for high throughput microscopy.

    PubMed

    Cheong, Brandon Huey-Ping; Liew, Oi Wah; Ng, Tuck Wah

    2013-08-01

    In high throughput microscopy, it is often assumed that the objects under investigation are fixed spatially. In addition, it is also presumed that the objects are sufficiently populated, otherwise there will be need to search through vast tracks of field of views before any recording can be done. The ability to collect objects at one location in the hydrated state is thus desirable and this is a challenge when the density of target objects in a sample is very low. In this work, we report that the generation of a squeezing flow from a circular coverslip compressing on suspensions is able to collect particulate (microbeads, fluorescent nanobeads and live algal cells) and non-particulate (EGFP) objects at the rim region of the coverslip. With a coverslip of 13 mm diameter, volumes between 2 µL and 4 µL were found to completely fill the coverslip without breaching the rims. Sample compression speeds between 100 µm/s and 1000 µm/s did not have any effect on object collection outcomes. In effect, the simple placement of coverslips on top the drop of sample by hand without a motorized translator was found to produce similar collection outcomes. Quantitative measurements confirmed that all the objects investigated were displaced and relocated at the rim regions to a very high degree. PMID:23733610

  10. MRT letter: Quantum noise removal and classification of breast mammogram images.

    PubMed

    Naseem, M Talha; Sulong, Ghazali Bin; Jaffar, M Arfan

    2012-12-01

    Because of the limitations of the X-ray hardware systems in mammogram machines, the quality of the breast mammogram images may undergo from poor resolution or low contrast. Quantum noise occurs in the mammogram images during acquisition due to low-count X-ray photons. In this work, an adaptive frost filter has been used to remove quantum noise. Local binary patterns have been extracted to classify breast mammograms into benign and malignant using different classifiers. Results show the superiority of the proposed algorithm in terms of sensitivity, specificity, and accuracy. Mammographic Institute Society Analysis database of mammography has been used for experimentation. Peak signal-to-noise ratio and structural similarity index measure are used to test the validity of adaptive frost filter. Experiment results show that proposed technique produces better results. PMID:23034955

  11. [The MRT of scaphoid pseudarthrosis with Gd-DTPA. Its staging and clinical correlation].

    PubMed

    Vogl, T J; Beutel, F; Wilhelm, K; Tempka, A; Schedel, H; Haas, R; Felix, R

    1994-11-01

    During a period of two years, 134 patients with pseudo-arthrosis of the scaphoid were examined by conventional radiography and by MRI in the course of a prospective study. The aim of the study was to define radiological staging using contrast enhanced MRI in order to improve the prognostic criteria. All MRI examinations were carried out with a 1.5 tesla scanner (SP63) using a surface coil and T1 weighted spin echo sequences in sagittal and frontal projection and frontal FLASH T2 sequences and axial spin echo T2 sequences. The T1 weighted SE sequences in frontal projection were carried out before and after iv contrast (0.1 mmol Gd-DTPA/kg KG). All sequences were compared with conventional radiographs and the operative findings. Eight patients in stage 0 showed high signal intensity of both fragments in T1 weighted SE sequences and at surgery there was good vascularisation. In 22 cases there was reduced signal intensity in at least one fragment (stage I). 45 patients with scaphoid pseudo-arthrosis showed complete signal loss but marked contrast uptake with still vital nuclei at surgery (stage II). In 22 patients, there was no increase in signal intensity after contrast and complete loss of vitality of the fragments at surgery. Staging was not possible in 37 patients because of previous operative intervention. The use of contrast enhanced MRI provides additional information compared with conventional radiography or plain MRI. PMID:7948999

  12. Christoph Scheiner's life between 1633 and 1650. (German Title: Christoph Scheiners Lebensjahre zwischen 1633 und 1650)

    NASA Astrophysics Data System (ADS)

    Daxecker, Franz

    In 1636, Christoph Scheiner left Rome where the trial of Galilei had taken place, and went to Vienna. The financing of his main work ``Rosa Ursina'' had to be clarified. Until 1636, Scheiner was not in office From 1636 onward, he was alternatively living in Neiße -- today Nysa (Silesia, Poland) -- and Vienna, from 1637 onward, he took his permanent residence in Neiße. Here, Scheiner worked as an advisor of the rector and as father confessor, in addition he gave religious lectures and looked after the garden.

  13. Zwischen Copernicus und Kepler - M. Michael Maestlinus Mathematicus Goeppingensis 1550-1631.

    NASA Astrophysics Data System (ADS)

    Betsch, Gerhard; Hamel, Jürgen

    This book contains the written versions of talks given at a symposium held in Tübingen between 2000 October 11 - 13, and organized by the faculty of physics of Tübingen University. Michael Mästlin (1550 - 1631) was an esteemed astronomer. He was among the first who described comets as cosmic bodies, and who attempted an orbital determination. Already at an early stage, he adhered to Copernicus' heliocentric system, which he transmitted to Kepler. During 47 years, Mästlin was a professor of mathematical sciences in Tübingen, and played an outstanding role in the scientific life of his university. The contributions deal with various aspects of the life and works of Mästlin: his well-received textbook of astronomy, his role in the rejection of the 1582 calender reform by the protestants, his celestial observations, his relation to Kepler and to Galilei, his position to the progress of science of his time. Other contributions analyze contemporary attempts of the quadrature of the circle, give an overview of Mästlin's surviving published and manuscript works, and provide a vivid decription of the everyday life of a Tübingen professor around 1600. All papers are written in German, and have English abstracts.

  14. The Kepler - Mästlin correspondence. (German Title: Der Briefwechsel zwischen Kepler und Mästlin)

    NASA Astrophysics Data System (ADS)

    Seck, Friedrich

    The correspondence between Kepler and Mästlin covers the period from 1594 to 1620. It is interrupted by year-long pauses and ends a full 10 years before Kepler's death. Initially, Mästlin is quite open to Kepler's new ideas (Mysterium Cosmographicum), but later he showed little understanding for the revolutionary innovations of the mature Kepler. Kepler's insistent wishes and the unfounded fear that Kepler might publish his letters gave rise to long periods of silence. Some passages in letters of his associates suggest that Mästlin suffered from melancholy (in today's terms: depression) induced by age.

  15. Der Haupthistokompatibilitätskomplex und die Unterscheidung zwischen Selbst und Fremd durch das Immunsystem

    NASA Astrophysics Data System (ADS)

    Klein, Jan; Rammensee, Hans-Georg; Nagy, Zoltan A.

    1983-06-01

    The major histocompatibility complex (Mhc) is a cluster of closely linked genes which are involved in the distinction between self and non-self. The genes fall into two classes, I and II, which are evolutionarily related but specialized to performing somewhat different functions. The Mhc genes code for proteins which are seen together with foreign substances by the thymus-derived lymphocytes. These lymphocytes thus recognize simultaneously self (Mhc molecules) and non-self (foreign antigen). Some of the Mhc genes are highly polymorphic and this polymorphism probably represents a compensation for the fact that certain combinations of Mhc molecules and antigen fail to be recognized by the T lymphocyte.

  16. Einstellung und Wissen von Lehramtsstudierenden zur Evolution - ein Vergleich zwischen Deutschland und der Türkei

    NASA Astrophysics Data System (ADS)

    Graf, Dittmar; Soran, Haluk

    Es wird eine Untersuchung vorgestellt, in der Wissen und Überzeugungen von Lehramtsstudierenden aller Fächer zum Thema Evolution an zwei Universitäten in Deutschland und der Türkei erhoben worden sind. Die Befragung wurde in Dortmund und in Ankara durchgeführt. Es stellte sich heraus, dass ausgeprägte Defizite im Verständnis der Evolutionsmechanismen herrschen. Viele Studierende, insbesondere aus der Türkei, sind nicht von der Faktizität der Evolution überzeugt. Dies gilt sowohl für Studierende mit Fach Biologie als auch für Studierende mit anderen Fächern. Näher untersucht worden sind die Faktoren, die die Überzeugungen zur Evolution beeinflussen können, was ja in Anbetracht der hohen Ablehnungsrate der Evolution von besonderem Interesse ist. Das Vertrauen in die Wissenschaft spielt hierbei eine besondere Rolle: Wer der Wissenschaft vertraut, ist auch eher von der Evolution überzeugt, als diejenigen, die skeptisch gegenüber der Wissenschaft sind.

  17. Diskrepanzen und Kongruenzen: Das Dilemma des afrikanischen Kindes zwischen Familie und Schule

    NASA Astrophysics Data System (ADS)

    Bauer, Annemarie

    1986-03-01

    This article expounds the theory that the failure of school is due to the incompatibility of the educational goals of school and traditional upbringing in Africa. The thesis is put forward by adherents of the psychoanalytical model of child development and seeks to emphasize the discrepancies between the childhood where children are not frustrated and where their needs are cared for and the school education which represses the drives and its socialization of children. Finding a number of anthropological studies are discussed and reinterpretations of the ethno-psychoanalytical materials attempted. Neither the evaluation of childhood in Africa nor the theory that with school come wholly new expectations of behaviour (e.g., a performance requirement) can no longer be maintained. In conclusion, other explanations for the difficulties encountered by school in Africa are offered.

  18. MRT letter: Spatial distribution of vancomycin-induced damage in Staphylococcus epidermidis biofilm: an electron microscopic study.

    PubMed

    Singh, Rachna; Ray, Pallab; Das, Anindita; Sharma, Meera

    2010-07-01

    This study was planned to elucidate the efficacy of antibiotics on Staphylococcus epidermidis and Staphylococcus aureus biofilms by scanning electron microscopy (SEM). Biofilms of S. epidermidis ATCC 35984 and S. aureus ATCC 29213 were grown on black, polycarbonate membranes placed on tryptic soy agar plates for 48 h at 37 degrees C, and then exposed to vancomycin or amikacin or ciprofloxacin at clinically achievable levels for 24 h at 37 degrees C. The morphology of antibiotic-treated and untreated biofilms was elucidated by SEM. SEM analysis indicated a differential affection of S. epidermidis ATCC 35984 in the center and periphery of biofilm upon treatment with vancomycin. The center of biofilm revealed damaged cells with sparse distribution, smaller size, and irregular shape, whereas cells in the periphery were unaffected. This differential distribution of susceptibility within S. epidermidis ATCC 35984 biofilms was specific for vancomycin only and was not observed on exposure to amikacin or ciprofloxacin. No such response was found in S.aureus ATCC 29213 biofilms. Thus, our study suggests a spatial distribution of vancomycin-induced damage in S. epidermidis biofilms. To our knowledge, this is the first report that indicates a differential affection of S. epidermidis in the center and periphery of biofilm upon treatment with vancomycin. Studies on the factors controlling this differential distribution could provide valuable insights into the mechanisms of antimicrobial resistance in S. epidermidis biofilms.

  19. Fielding the magnetically applied pressure-shear technique on the Z accelerator (completion report for MRT 4519).

    SciTech Connect

    Alexander, C. Scott; Haill, Thomas A.; Dalton, Devon Gardner; Rovang, Dean Curtis; Lamppa, Derek C.

    2013-09-01

    The recently developed Magnetically Applied Pressure-Shear (MAPS) experimental technique to measure material shear strength at high pressures on magneto-hydrodynamic (MHD) drive pulsed power platforms was fielded on August 16, 2013 on shot Z2544 utilizing hardware set A0283A. Several technical and engineering challenges were overcome in the process leading to the attempt to measure the dynamic strength of NNSA Ta at 50 GPa. The MAPS technique relies on the ability to apply an external magnetic field properly aligned and time correlated with the MHD pulse. The load design had to be modified to accommodate the external field coils and additional support was required to manage stresses from the pulsed magnets. Further, this represents the first time transverse velocity interferometry has been applied to diagnose a shot at Z. All subsystems performed well with only minor issues related to the new feed design which can be easily addressed by modifying the current pulse shape. Despite the success of each new component, the experiment failed to measure strength in the samples due to spallation failure, most likely in the diamond anvils. To address this issue, hydrocode simulations are being used to evaluate a modified design using LiF windows to minimize tension in the diamond and prevent spall. Another option to eliminate the diamond material from the experiment is also being investigated.

  20. Dilemmata der ErzieherInnenausbildung Zwischen Institution und Profession (The Dilemma of Educational Training between Institution and Profession).

    ERIC Educational Resources Information Center

    Engelhardt, Walter Josef; Ernst, Heinz

    1992-01-01

    Discusses the change in kindergarten from an emergency or welfare institution to an integral part of family life and early education. Argues that, although the nature of kindergarten has changed, the training of kindergarten teachers has not. Suggests that future kindergarten teachers be trained in teaching theory rather than just personality…

  1. Zwischen Web 2.0, virtuellen Welten und Game-based Learning - Einsatzszenarien und Prototypen im Hochschulumfeld

    NASA Astrophysics Data System (ADS)

    Pongratz, Hans

    Web 2.0, virtuelle Welten und Game-based Learning werden als Allheilmittel moderner Wissensvermittlung an Hochschulen genannt. Dieser Artikel beschreibt nach einer Einführung in die Thematik Einsatzszenarien und Prototypen im Hochschulumfeld anhand ausgewählter Web 2.0-Dienste, der virtuellen Welt Second Life, eines an der TUM entwickelten Frameworks für Gamebased Learning Applikationen und eines Lernspiels. Diese werden anhand von konkreten Lehr- und Lernszenarien vorgestellt und anhand der bisherigen Erfahrungen in diesem Bereich kritisch beleuchtet.

  2. Effect of random structure on permeability and heat transfer characteristics for flow in 2D porous medium based on MRT lattice Boltzmann method

    NASA Astrophysics Data System (ADS)

    Yang, PeiPei; Wen, Zhi; Dou, RuiFeng; Liu, Xunliang

    2016-08-01

    Flow and heat transfer through a 2D random porous medium are studied by using the lattice Boltzmann method (LBM). For the random porous medium, the influence of disordered cylinder arrangement on permeability and Nusselt number are investigated. Results indicate that the permeability and Nusselt number for different cylinder locations are unequal even with the same number and size of cylinders. New correlations for the permeability and coefficient b‧Den of the Forchheimer equation are proposed for random porous medium composed of Gaussian distributed circular cylinders. Furthermore, a general set of heat transfer correlations is proposed and compared with existing experimental data and empirical correlations. Our results show that the Nu number increases with the increase of the porosity, hence heat transfer is found to be accurate considering the effect of porosity.

  3. MRT letter: high resolution SEM imaging of nano-architecture of cured urea-formaldehyde resin using plasma coating of osmium.

    PubMed

    Park, Byung-Dae; Singh, Adya P; Nuryawan, Arif; Hwang, Kiju

    2013-11-01

    Nanoarchitecture of cured urea-formaldehyde (UF) resins was examined with a field-emission scanning electron microscope (FE-SEM) after coating samples with osmium, which is considered to produce particles of considerably smaller size compared to other metal coatings used in SEM studies. This method enabled comparison of the nanoarchitecture of UF resins of low (1.0) and high (1.6) formaldehyde/urea (F/U) mole ratios to be made, based on imaging of extremely small size particles as part of UF resin architecture, not described before. Imaging revealed presence of relatively large globular particles (148.084-703.983 nm size range) as well as smaller substructures (28.004-39.604 nm size range) as part of the architecture of 1.0-mole UF resin. Globular particles were also present in 1.6 mole UF resin, but of considerably smaller size (14.760-50.269 nm). The work presented demonstrates usefulness of osmium coating in unraveling the intricacies of the nanostructural organization of cured UF resins, prompting wider application of this immensely useful but grossly underutilized metal coating type in high resolution SEM examination of biological and materials samples.

  4. Zwischen Gesetz und Fall. Mutmassungen uber Typologien als Padagogische Wissensform (Between General Law and the Individual Case. Conjectures Concerning Typologies as a Form of Pedagogical Knowledge).

    ERIC Educational Resources Information Center

    Herzog, Walter

    2003-01-01

    Considers the mediation between scientific knowledge and practical action as a crucial feature of professional teaching. Investigates the assumption that typologies represent a form of knowledge which can bridge the gap between theory and practice. Differentiates between two forms of typological thinking and discusses reservations concerning…

  5. Zwischen "Fassade" und "wirklicher Absicht": Eine Betrachtung uber die dritte Erziehungsreform in Japan = Between "Facade" and "Real Intent": Observations on Japan's Third Educational Reform.

    ERIC Educational Resources Information Center

    Ito, Toshiko

    1997-01-01

    Asserts that the Japanese educational system consists of the "facade" of ministerially-decreed harmony and the "real intent" of competition. Argues that the balance between the two has been endangered by recent reforms that seek to promote "creativity and diversification." Suggests that policymakers did not analyze factors that might impede…

  6. The Astronomische Gesellschaft between international activities and national barriers (1863-1933). (German Title: Die Astronomische Gesellschaft zwischen internationaler Wirksamkeit und nationalen Schranken (1863-1933))

    NASA Astrophysics Data System (ADS)

    Dick, Wolfgang R.

    The Astronomische Gesellschaft (AG), founded in 1863, was always intended to be an international society of astronomers, but it was at the same time always dominated by German astronomers. This is expressed in the national background of the members and in the usage of German as the business language, as well as in other facts. It is shown that this polarity between international activities and national barriers originated in the circumstances of the foundation. Using examples from publications and archival sources, the international activities of the AG and the relation of some members to these are being traced between 1863 and 1933. For this the regulations in the statutes, the activities and the relation to the International Astronomical Union have been analysed.

  7. "Astronomica" in the Correspondence between Leonhard Euler and Daniel Bernoull (German Title: "Astronomica" im Briefwechsel zwischen Leonhard Euler und Daniel Bernoulli)

    NASA Astrophysics Data System (ADS)

    Verdun, Andreas

    2010-12-01

    The Euler Commission of the Swiss Academy of Sciences intends to terminate the edition of Leonhard Euler's works in the next year 2011 after nearly one hundred years since the beginning of the editorial works. These works include, e.g., Volume 3 of the Series quarta A which will contain the correspondence between Leonhard Euler (1707-1783) and Daniel Bernoulli (1700-1783) and which is currently being edited by Dr. Emil A. Fellmann (Basel) and Prof. Dr. Gleb K. Mikhailov (Moscow). This correspondence contains more than hundred letters, principally from Daniel Bernoulli to Euler. Parts of this correspondence were published uncommented already in 1843. It is astonishing that, apart from mathematics and physics (mainly mechanics and hydrodynamics), many topics addressed concern astronomy. The major part of the preserved correspondence between Euler and Daniel Bernoulli, in which astronomical themes are discussed, concerns celestial mechanics as the dominant discipline of theoretical astronomy of the eighteenth century. It was triggered and coined mainly by the prize questions of the Paris Academy of Science. In more than two thirds of the letters current problems and questions concerning celestial mechanics of that time are treated, focusing on the lunar theory and the great inequality in the motions of Jupiter and Saturn as special applications of the three body problem. In the remaining letters, problems concerning spherical astronomy are solved and attempts are made to explain certain phenomena in the field of "cosmic physics" concerning astronomical observations.

  8. 75 FR 81287 - Mortgagee Review Board: Administrative Actions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-27

    .... RJ Financial Services, Inc., San Antonio, TX, 10-1488-MRT 21. Robert P. Lenz & Associates, Inc.... Midwest Mortgage Partners LLC, Clive, IA, 10-1466-MRT 78. Mortgage Strategies Inc., Benicia, CA,...

  9. Confidence and Gender Differences on the Mental Rotations Test

    ERIC Educational Resources Information Center

    Cooke-Simpson, Amanda; Voyer, Daniel

    2007-01-01

    The present study examined the relation between self-reported confidence ratings, performance on the Mental Rotations Test (MRT), and guessing behavior on the MRT. Eighty undergraduate students (40 males, 40 females) completed the MRT while rating their confidence in the accuracy of their answers for each item. As expected, gender differences in…

  10. The master and the telescopes - the interplay between astronomy and optics in history (German Title: Der Meister und die Fernrohre - Das Wechselspiel zwischen Astronomie und Optik in der Geschichte)

    NASA Astrophysics Data System (ADS)

    Hamel, Jürgen; Keil, Inge

    The use of the telescope for astronomical observations since 1609 was one of the milestones in the celestial research. The contributions in this volume present new insights into the invention of the telescope and its relations to reading stones and spectacles, present investigations of special telescope types of early manufacturers, and analyze the telescopes of some historical observatories and the investigations carried out with them. Other contributions deal with the pictorial appearance of telescopes in baroque art, the connection of telescopes with photography, as well as the development of reflectors in the 20th century. The volume is dedicated to Rolf Riekher, an internationally established specialist ior the history of the telescope, on the occasion of his 85th birthday.

  11. Der Begriff des "Ki" und die japanische Padagogik: Uber Konflikte zwischen westlicher und japanischer Padagogik (The Concept of "Ki" and Japanese Pedagogy: On Conflicts between Western and Japanese Pedagogics).

    ERIC Educational Resources Information Center

    Fujikawa, Nobuo

    1997-01-01

    Sketches the characteristics of the Japanese educational tradition and analyzes conflicts between modern western pedagogies and traditional education. Argues that Japanese socialization processes stress a specifically Japanese construction of the "self" and of behavior. Concludes that Japanese educators should be more aware of this element in the…

  12. The correspondence between H.C. Schumacher and H.C. Oersted (Ørsted). (German Title: Der Briefwechsel zwischen H.C. Schumacher und H.C. Oersted (Ørsted))

    NASA Astrophysics Data System (ADS)

    Hamel, Jürgen

    This paper summarizes the correspondence of H.C. Schumacher (1780-1850) and H.C. Oersted (1777-1851) which is kept among the Schumacher papers in the State Library at Berlin. Some letters, published already in 1920 in a partial edition of Oersted's correspondence are included. The intensity of their cooperation, the variety of topics, as well as the personal relation of the correspondents are clearly indicated in the texts. Since the complete letters cannot be published here, only the most important parts are cited literally.

  13. Zwischen Wollen, aber nicht können und Können, aber nicht wollen: Übergangsprobleme von Jugendlichen in Japan am Beispiel der „Freeter`` und „NEETs``

    NASA Astrophysics Data System (ADS)

    Eswein, Mikiko; Pilz, Matthias

    2012-08-01

    Caught between wanting but not being able to, and being able, but not wanting to: Transitional problems among Japanese youths based on the examples of "Freeters" and "NEETs" - The study of processes of transition from the education system to employment is particularly important in light of youth unemployment. In Japan this transition process is often declared to be successful. In recent years, however, numerous signs have indicated a change in the situation. This article analyses this problem based on the examples of two Japanese social groups, "Freeters" and "NEETs". These terms refer to young adults who do not immediately move into to regular employment. The article begins by analysing the causes, then comments on education policy measures undertaken to tackle the issue. Drawing on scientifically grounded models it is shown that both social groups are characterised by meagre formal school qualifications. Social background, by contrast, is not particularly relevant; although there are hints that parents' financial means play an increasingly important role in determining whether a young person attends a high-level educational institution. Although public opinion in Japan frequently attributes values and attitudes to these groups that deviate from the norm, this is not conclusively supported by existing empirical findings. Consequently, the reasons for these transitional problems tend to be perceived as being connected to the difficult labour market situation resulting from the ongoing economic crisis. In addition to certain education policy initiatives, Japan will therefore rely heavily in future on the ability to effectively manage the integration of its shrinking cohorts of school and university graduates.

  14. The controversy between Alexander Friedmann and Albert Einstein about the possibility of a non-static world (German Title: Die Kontroverse zwischen Alexander Friedmann und Albert Einstein um die Möglichkeit einer nichtstatischen Welt)

    NASA Astrophysics Data System (ADS)

    Singer, Georg

    Einstein's treatment of the cosmological problem as well as his unshakeable adherence to his own static solution of the complete field equations was throughout determined by Ernst Mach's idea of relativity of inertia. Friedmann, however, like Eddington, Weyl and others did not consider Mach's principle to be a part of general relativity, and so he regarded a time dependent developing spatial geometry as being consistent with world matter at relative rest. In his final statement to the controversy, Einstein acknowledged just formal correctness of Friedmann's results. Actually his criticism was not due ``to a miscalculation'', as he was ready to admit, but was owed to a fundamental fixed idea which continued to exist and which was the cause of his disavowal of physical significance of dynamical solutions.

  15. Zwischen den Stuhlen: Untersuchungen zur Situation der Korrektoren an der Fernuniversitat 1980, (In between Chairs: The Situation of Tutors (Correctors) at the FernUniversitat in 1980). ZIFF Papiere 34.

    ERIC Educational Resources Information Center

    Fritsch, Helmut; And Others

    An empirical study of tutors responsible for evaluating students' assignments at the Fernuniversitat in 1980 employed an 18-item questionnaire, analysis of open-ended responses, analysis of graders' comments on more than 1,000 assignments, and interviews with staff. The process of evaluating students' work was shown to be inefficient, with minimal…

  16. Chalcone JAI-51 improves efficacy of synchrotron microbeam radiation therapy of brain tumors.

    PubMed

    Bouchet, Audrey; Boumendjel, Ahcene; Khalil, Enam; Serduc, Raphael; Bräuer, Elke; Siegbahn, Erik Albert; Laissue, Jean A; Boutonnat, Jean

    2012-07-01

    Microbeam radiation therapy (MRT), a preclinical form of radiosurgery, uses spatially fractionated micrometre-wide synchrotron-generated X-ray beams. As MRT alone is predominantly palliative for animal tumors, the effects of the combination of MRT and a newly synthesized chemotherapeutic agent JAI-51 on 9L gliosarcomas have been evaluated. Fourteen days (D14) after implantation (D0), intracerebral 9LGS-bearing rats received either MRT, JAI-51 or both treatments. JAI-51, alone or immediately after MRT, was administered three times per week. Animals were kept up to ∼20 weeks after irradiation or sacrificed at D16 or D28 after treatment for cell cycle analysis. MRT plus JAI-51 increased significantly the lifespan compared with MRT alone (p = 0.0367). JAI-51 treatment alone had no effect on rat survival. MRT alone or associated with JAI-51 induced a cell cycle blockade in G2/M (p < 0.01) while the combined treatment also reduced the proportion of G0/G1 cells. At D28 after irradiation, MRT and MRT/JAI-51 had a smaller cell blockade effect in the G2/M phase owing to a significant increase in tumor cell death rate (<2c) and a proportional increase of endoreplicative cells (>8c). The combination of MRT and JAI-51 increases the survival of 9LGS-bearing rats by inducing endoreduplication of DNA and tumor cell death; further, it slowed the onset of tumor growth resumption two weeks after treatment.

  17. Theoretical and Experimental Studies of Magneto-Rayleigh-Taylor Instabilities

    SciTech Connect

    Lau, Yue Ying; Gilgenbach, Ronald

    2013-07-07

    Magneto-Rayleigh-Taylor instability (MRT) is important to magnetized target fusion, wire-array z-pinches, and equation-of-state studies using flyer plates or isentropic compression. It is also important to the study of the crab nebula. The investigators performed MRT experiments on thin foils, driven by the mega-ampere linear transformer driver (LTD) facility completed in their laboratory. This is the first 1-MA LTD in the USA. Initial experiments on the seeding of MRT were performed. Also completed was an analytic study of MRT for a finite plasma slab with arbitrary magnetic fields tangential to the interfaces. The effects of magnetic shear and feedthrough were analyzed.

  18. Engineered Modular Recombinant Transporters: Application of New Platform for Targeted Radiotherapeutic Agents to {alpha}-Particle Emitting {sup 211}At

    SciTech Connect

    Rosenkranz, Andrey A.; Vaidyanathan, Ganesan; Pozzi, Oscar R.; Lunin, Vladimir G.; Zalutsky, Michael R. Sobolev, Alexander S.

    2008-09-01

    Purpose: To generate and evaluate a modular recombinant transporter (MRT) for targeting {sup 211}At to cancer cells overexpressing the epidermal growth factor receptor (EGFR). Methods and Materials: The MRT was produced with four functional modules: (1) human epidermal growth factor as the internalizable ligand, (2) the optimized nuclear localization sequence of simian vacuolating virus 40 (SV40) large T-antigen, (3) a translocation domain of diphtheria toxin as an endosomolytic module, and (4) the Escherichia coli hemoglobin-like protein (HMP) as a carrier module. MRT was labeled using N-succinimidyl 3-[{sup 211}At]astato-5-guanidinomethylbenzoate (SAGMB), its {sup 125}I analogue SGMIB, or with {sup 131}I using Iodogen. Binding, internalization, and clonogenic assays were performed with EGFR-expressing A431, D247 MG, and U87MG.wtEGFR human cancer cell lines. Results: The affinity of SGMIB-MRT binding to A431 cells, determined by Scatchard analysis, was 22 nM, comparable to that measured before labeling. The binding of SGMIB-MRT and its internalization by A431 cancer cells was 96% and 99% EGFR specific, respectively. Paired label assays demonstrated that compared with Iodogen-labeled MRT, SGMIB-MRT and SAGMB-MRT exhibited more than threefold greater peak levels and durations of intracellular retention of activity. SAGMB-MRT was 10-20 times more cytotoxic than [{sup 211}At]astatide for all three cell lines. Conclusion: The results of this study have demonstrated the initial proof of principle for the MRT approach for designing targeted {alpha}-particle emitting radiotherapeutic agents. The high cytotoxicity of SAGMB-MRT for cancer cells overexpressing EGFR suggests that this {sup 211}At-labeled conjugate has promise for the treatment of malignancies, such as glioma, which overexpress this receptor.

  19. Constructive Play: Building Symbolic Competence through Physical Activity and Social Interaction.

    ERIC Educational Resources Information Center

    Fennel, Linda

    Whether physical activity and verbal communication would affect kindergarten students' scores on the Metropolitan Readiness Tests (MRT) was investigated. Twenty subjects were administered Level I of the MRT when they entered kindergarten. For 5 days per week for 4 weeks, the 10 subjects in the experimental group worked at constructive play tasks…

  20. Comments on "A modified reachability tree approach to analysis of unbounded Petri nets".

    PubMed

    Ru, Yu; Wu, Weimin; Hadjicostis, Christoforos N

    2006-10-01

    The above paper introduced the construction of a modified reachability tree (MRT) for (unbounded) Petri nets and its application to reachability, liveness, and deadlock analysis. This note shows via a counterexample that some of the MRT properties claimed in the above paper are incorrect.

  1. Item Type and Gender Differences on the Mental Rotations Test

    ERIC Educational Resources Information Center

    Voyer, Daniel; Doyle, Randi A.

    2010-01-01

    This study investigated gender differences on the Mental Rotations Test (MRT) as a function of item and response types. Accordingly, 86 male and 109 female undergraduate students completed the MRT without time limits. Responses were coded as reflecting two correct (CC), one correct and one wrong (CW), two wrong (WW), one correct and one blank…

  2. CD146 is a novel marker for highly tumorigenic cells and a potential therapeutic target in malignant rhabdoid tumor

    PubMed Central

    Nodomi, S; Umeda, K; Saida, S; Kinehara, T; Hamabata, T; Daifu, T; Kato, I; Hiramatsu, H; Watanabe, K-i; Kuwahara, Y; Iehara, T; Adachi, S; Konishi, E; Nakahata, T; Hosoi, H; Heike, T

    2016-01-01

    Malignant rhabdoid tumor (MRT) is a rare, highly aggressive pediatric malignancy that primarily develops during infancy and early childhood. Despite the existing standard of intensive multimodal therapy, the prognosis of patients with MRT is dismal; therefore, a greater understanding of the biology of this disease is required to establish novel therapies. In this study, we identified a highly tumorigenic sub-population in MRT, based on the expression of CD146 (also known as melanoma cell adhesion molecule), a cell adhesion molecule expressed by neural crest cells and various derivatives. CD146+ cells isolated from four MRT cell lines by cell sorting exhibited enhanced self-renewal and invasive potential in vitro. In a xenograft model using immunodeficient NOD/Shi-scid IL-2Rγ-null mice, purified CD146+ cells obtained from MRT cell lines or a primary tumor exhibited the exclusive ability to form tumors in vivo. Blocking of CD146-related mechanisms, either by short hairpin RNA knockdown or treatment with a polyclonal antibody against CD146, effectively suppressed tumor growth of MRT cells both in vitro and in vivo via induction of apoptosis by inactivating Akt. Furthermore, CD146 positivity in immunohistological analysis of 11 MRT patient samples was associated with poor patient outcomes. These results suggest that CD146 defines a distinct sub-population in MRT with high tumorigenic capacity and that this marker represents a promising therapeutic target. PMID:27041577

  3. Minimum resolvable temperature difference measurements on undersampled imagers

    NASA Astrophysics Data System (ADS)

    Driggers, Ronald G.; Hodgkin, Van A.; Vollmerhausen, Richard H.; O'Shea, Patrick

    2003-08-01

    Minimum Resolvable Temperature Difference (MRTD) is the primary measurement of performance for infrared imaging systems. Where Modulation Transfer Function (MTF) is a measurement of resolution and three-dimensional noise (or noise equivalent temperature difference) is a measurement of sensitivity, MRTD combines both measurements into a test of observer visual acuity through the imager. MRTD has been incorrectly applied to undersampled thermal imagers as a means for assessing the overall performance of the imager. The incorrect application of the MRTD (or just MRT) test to undersampled imagers includes testing to the half-sample (or Nyquist rate) of the sensor and calling the MRT unresolvable beyond this frequency. This approach is known to give poor predictions in overall system performance. Also, measurements at frequencies below the half-sample rate are strongly dependent on the phase between the sampling geometry and the four-bar target. The result is that very little information in the MRT measurement of an undersampled thermal imager is useful. There are a number of alternatives including Dynamic MRT (DMRT), Minimum Temperature Difference Perceived (MTDP), Triangle Orientation Discrimination (TOD), and objective MRT tests. The NVESD approach is to measure the MTF and system noise and to use these measurements in the MRT calculation to give good sensor performance predictions. This paper describes the problems with MRT for undersampled imagers, describes the alternative measurements, and presents the NVESD approach to MRT measurements.

  4. Master Resilience Training in the U.S. Army

    ERIC Educational Resources Information Center

    Reivich, Karen J.; Seligman, Martin E. P.; McBride, Sharon

    2011-01-01

    The U.S. Army Master Resilience Trainer (MRT) course, which provides face-to-face resilience training, is one of the foundational pillars of the Comprehensive Soldier Fitness program. The 10-day MRT course is the foundation for training resilience skills to sergeants and for teaching sergeants how to teach these skills to their soldiers. The…

  5. An Investigation of the Relationship Between Readiness Test Scores for Kindergarten Children and Achievement Scores Obtained at the End of Grades One and Two. S.S.T.A. Research Centre Report No. 62.

    ERIC Educational Resources Information Center

    Warkentin, Lena

    The primary purpose of this study was to investigate the relationship between Metropolitan Readiness Test (MRT) scores in kindergarten (MRTK) and grade one (MRT1) with the reading scores of the Canadian Tests of Basic Skills (CTBS) at the end of grades one (CTBSR1) and two (CTBSR2). A secondary purpose of the study was to determine whether the…

  6. Learning Anatomy Enhances Spatial Ability

    ERIC Educational Resources Information Center

    Vorstenbosch, Marc A. T. M.; Klaassen, Tim P. F. M.; Donders, A. R. T.; Kooloos, Jan G. M.; Bolhuis, Sanneke M.; Laan, Roland F. J. M.

    2013-01-01

    Spatial ability is an important factor in learning anatomy. Students with high scores on a mental rotation test (MRT) systematically score higher on anatomy examinations. This study aims to investigate if learning anatomy also oppositely improves the MRT-score. Five hundred first year students of medicine ("n" = 242, intervention) and…

  7. Tumor Cell Response to Synchrotron Microbeam Radiation Therapy Differs Markedly From Cells in Normal Tissues

    SciTech Connect

    Crosbie, Jeffrey C.; Anderson, Robin L.; Rothkamm, Kai; Restall, Christina M.; Cann, Leonie; Ruwanpura, Saleela; Meachem, Sarah; Yagi, Naoto; Svalbe, Imants; Lewis, Robert A.; Williams, Bryan R.G.; Rogers, Peter A.W.

    2010-07-01

    Purpose: High-dose synchrotron microbeam radiation therapy (MRT) can be effective at destroying tumors in animal models while causing very little damage to normal tissues. The aim of this study was to investigate the cellular processes behind this observation of potential clinical importance. Methods and Materials: MRT was performed using a lattice of 25 {mu}m-wide, planar, polychromatic, kilovoltage X-ray microbeams, with 200-{mu}m peak separation. Inoculated EMT-6.5 tumor and normal mouse skin tissues were harvested at defined intervals post-MRT. Immunohistochemical detection of {gamma}-H2AX allowed precise localization of irradiated cells, which were also assessed for proliferation and apoptosis. Results: MRT significantly reduced tumor cell proliferation by 24 h post-irradiation (p = 0.002). An unexpected finding was that within 24 h of MRT, peak and valley irradiated zones were indistinguishable in tumors because of extensive cell migration between the zones. This was not seen in MRT-treated normal skin, which appeared to undergo a coordinated repair response. MRT elicited an increase in median survival times of EMT-6.5 and 67NR tumor-inoculated mice similar to that achieved with conventional radiotherapy, while causing markedly less normal tissue damage. Conclusions: This study provides evidence of a differential response at a cellular level between normal and tumor tissues after synchrotron MRT.

  8. Beyond Genetics in Mental Rotation Test Performance: The Power of Effort Attribution

    ERIC Educational Resources Information Center

    Moe, Angelica; Pazzaglia, Francesca

    2010-01-01

    This study compares the effects on Mental Rotation Test (MRT) performance of instructions that stress the importance of (a) personal effort, and (b) genetically driven ability. A total of 120 high-school students were assigned to three groups, and administered two sub-tests of the MRT. Between the first and second sub-tests, the groups received…

  9. Comparison of mean radiant temperature from field experiment and modelling: a case study in Freiburg, Germany

    NASA Astrophysics Data System (ADS)

    Chen, Yung-Chang; Lin, Tzu-Ping; Matzarakis, Andreas

    2014-11-01

    Mean radiant temperature ( T mrt) based on two measurement methods and outputs from three models are compared in this study. They are the six direction radiation method, globe thermometer method, RayMan model, ENVI-met model and SOLWEIG model. The comparison shows that globe thermometer method may overestimate the T mrt since wind velocity is a key variable in the estimation based on this method. For better estimation, T mrt measured by the globe-thermometer method be corrected by the imported wind speed (stable, low and assuming wind speed) and validated by the six-direction radiation method. The comparison of models shows that the RayMan model's evaluation of T mrt involving global radiation with fine time resolution was better than the corresponding evaluations under the other two models (ENVI-met and SOLWEIG) in this case. However, the RayMan model can only assess T mrt for a one-point one-time context, whereas the other two models can evaluate two-dimensional T mrt. For two-dimensional evaluations of T mrt, SOLWEIG have a better prediction of T mrt than ENVI-met, and ENVI-met can simulate several different variables, which are wind field, particle distribution, CO2 distribution and the other thermal parameters ( T a, surface temperature and radiation fluxes), that SOLWEIG cannot.

  10. Treating Brain Tumor with Microbeam Radiation Generated by a Compact Carbon-Nanotube-Based Irradiator: Initial Radiation Efficacy Study

    PubMed Central

    Yuan, Hong; Zhang, Lei; Frank, Jonathan E.; Inscoe, Christina R.; Burk, Laurel M.; Hadsell, Mike; Lee, Yueh Z.; Lu, Jianping; Chang, Sha; Zhou, Otto

    2015-01-01

    Microbeam radiation treatment (MRT) using synchrotron radiation has shown great promise in the treatment of brain tumors, with a demonstrated ability to eradicate the tumor while sparing normal tissue in small animal models. With the goal of expediting the advancement of MRT research beyond the limited number of synchrotron facilities in the world, we recently developed a compact laboratory-scale microbeam irradiator using carbon nanotube (CNT) field emission-based X-ray source array technology. The focus of this study is to evaluate the effects of the microbeam radiation generated by this compact irradiator in terms of tumor control and normal tissue damage in a mouse brain tumor model. Mice with U87MG human glioblastoma were treated with sham irradiation, low-dose MRT, high-dose MRT or 10 Gy broad-beam radiation treatment (BRT). The microbeams were 280 µm wide and spaced at 900 µm center-to-center with peak dose at either 48 Gy (low-dose MRT) or 72 Gy (high-dose MRT). Survival studies showed that the mice treated with both MRT protocols had a significantly extended life span compared to the untreated control group (31.4 and 48.5% of life extension for low- and high-dose MRT, respectively) and had similar survival to the BRT group. Immunostaining on MRT mice demonstrated much higher DNA damage and apoptosis level in tumor tissue compared to the normal brain tissue. Apoptosis in normal tissue was significantly lower in the low-dose MRT group compared to that in the BRT group at 48 h postirradiation. Interestingly, there was a significantly higher level of cell proliferation in the MRT-treated normal tissue compared to that in the BRT-treated mice, indicating rapid normal tissue repairing process after MRT. Microbeam radiation exposure on normal brain tissue causes little apoptosis and no macrophage infiltration at 30 days after exposure. This study is the first biological assessment on MRT effects using the compact CNT-based irradiator. It provides an alternative

  11. "Mitochondrial Replacement" Technologies and Human Germline Nuclear Modification.

    PubMed

    Lane, Alyssa; Nisker, Jeff

    2016-08-01

    In 2015 the United Kingdom became the first jurisdiction to approve "mitochondrial replacement techniques" (MRT), thereby dropping prohibitions against creating human embryos with a permanently altered genetic make-up for purposes of reproduction. MRT is a misnomer because in fact it is the nucleus of the oocyte of the woman who wants a genetically related child that is transferred to the enucleated oocyte of a woman paid to undergo IVF to provide the oocyte. MRT thus constitutes nuclear transfer, which is prohibited by criminal sanctions under sections of laws on reproductive cloning in Canada, the United States, Australia, and European countries that regulate assisted reproduction. By adopting policies permitting the use of MRT, the United Kingdom has become the first jurisdiction to counteract an international consensus prohibiting germline modification. Analyses of the legal, ethical, and societal implications of MRT in assisted human reproduction are essential. PMID:27638985

  12. Nanotube x-ray for cancer therapy: a compact microbeam radiation therapy system for brain tumor treatment

    PubMed Central

    Zhang, Lei; Yuan, Hong; Inscoe, Christina; Chtcheprov, Pavel; Hadsell, Michael; Lee, Yueh; Lu, Jianping; Chang, Sha; Zhou, Otto

    2014-01-01

    Microbeam radiation therapy (MRT) is a promising preclinical modality for cancer treatment, with remarkable preferential tumoricidal effects, that is, tumor eradication without damaging normal tissue functions. Significant lifespan extension has been demonstrated in brain tumor-bearing small animals treated with MRT. So far, MRT experiments can only be performed in a few synchrotron facilities around the world. Limited access to MRT facilities prevents this enormously promising radiotherapy technology from reaching the broader biomedical research community and hinders its potential clinical translation. We recently demonstrated, for the first time, the feasibility of generating microbeam radiation in a laboratory environment using a carbon nanotube x-ray source array and performed initial small animal studies with various brain tumor models. This new nanotechnology-enabled microbeam delivery method, although still in its infancy, has shown promise for achieving comparable therapeutic effects to synchrotron MRT and has offered a potential pathway for clinical translation. PMID:25417729

  13. Validation of the mean radiant temperature simulated by the RayMan software in urban environments

    NASA Astrophysics Data System (ADS)

    Lee, Hyunjung; Mayer, Helmut

    2016-04-01

    The RayMan software is worldwide applied in investigations on different issues in human-biometeorology. However, only the simulated mean radiant temperature (T mrt) has been validated so far in a few case studies. They are based on T mrt values, which were experimentally determined in urban environments by use of a globe thermometer or applying the six-directional method. This study analyses previous T mrt validations in a comparative manner. Their results are extended by a recent validation of T mrt in an urban micro-environment in Freiburg (southwest Germany), which can be regarded as relatively heterogeneous due to different shading intensities by tree crowns. In addition, a validation of the physiologically equivalent temperature (PET) simulated by RayMan is conducted for the first time. The validations are based on experimentally determined T mrt and PET values, which were calculated from measured meteorological variables in the daytime of a clear-sky summer day. In total, the validation results show that RayMan is capable of simulating T mrt satisfactorily under relatively homogeneous site conditions. However, the inaccuracy of simulated T mrt is increasing with lower sun elevation and growing heterogeneity of the simulation site. As T mrt represents the meteorological variable that mostly governs PET in the daytime of clear-sky summer days, the accuracy of simulated T mrt is mainly responsible for the accuracy of simulated PET. The T mrt validations result in some recommendations, which concern an update of physical principles applied in the RayMan software to simulate the short- and long-wave radiant flux densities, especially from vertical building walls and tree crowns.

  14. Impact of new water systems on healthcare-associated colonization or infection with Pseudomonas aeruginosa.

    PubMed

    Lefebvre, Annick; Quantin, Catherine; Vanhems, Philippe; Lucet, Jean-Christophe; Bertrand, Xavier; Astruc, Karine; Chavanet, Pascal; Aho-Glélé, Ludwig S

    2016-01-01

    Zielsetzung: Untersucht werden sollte der Einfluss eines neuen weniger mit P. aeruginosa kontaminierten Wassersystems auf die Inzidenz nosokomialer Kolonisation oder Infektion mit P. aeruginosa in Pflegeeinheiten, die zwischen 2005 und 2014 in ein anderes Gebäude verlagert wurden. Methode: Mit dem Modell der generalisierten Schätzgleichungen (Generalized Estimated Equations) wurde die Inzidenz nosokomialer Fällen von P. aeruginosa zwischen den beiden Gebäuden verglichen. Ergebnisse: 29 Einheiten mit 2.759 in diesen Einheiten nachgewiesenen Fällen wurden während des Studienzeitraums verlagert. Zwischen dem neuem und dem alten Gebäude war keine Differenz nachweisbar.Schlussfolgerung: Die Ergebnisse unterstützen nicht die Hypothese einer positiven Assoziation zwischen der Trinkwasserkontamination und der Inzidenz nosokomialer P. aeruginosa-Fälle. Allerdings bedarf diese Aussage der Überprüfung des Zusammenhangs zwischen kontaminierten Wasserproben und Patientendaten.

  15. Schule in der Transformation--Transformation der Schule? Was man aus Gesprachen mit ehemaligen Schulern uber die Schule "zwischen zwei Diktaturen" erfahren kann (Schools in Transitions--Transformation of the School? What Can Be Learnt from Former Students Who Experienced Schooling under Two Dictatorial Regimes).

    ERIC Educational Resources Information Center

    Kluchert, Gerhard; Leschinsky, Achim

    1998-01-01

    Addresses interviews that focused on former students' educations under two dictatorial regimes. All the interviewees took their school-leaving examinations between 1951 and 1954. Explains that the interviews are evaluated according to the preconditions, limits, and mechanisms of the school's influence on children and adolescents. (CMK)

  16. Astronomical discoveries and the renown of a late humanistic scholar - Marx Welser's role in the discussion on sunspots between Scheiner, Galilei and Kepler. (German Title: Astronomische Entdeckungen und das Renommee eies späthumanistischen Gelehrten - Marx Welsers Rolle in der Sonnenfleckendiskussion zwischen Scheiner, Galilei und Kepler)

    NASA Astrophysics Data System (ADS)

    Ferber, Magnus Ulrich

    The example of the late humanistic scholar Max Welser (1558-1614) from Augsburg proves the gain of recognition of astronomy in the scholarly surroundings, which arose through its new results after the invention of the telescope. This explains why an exponent of the humanistic ideal of education worked towards appearing as the patron of a professional astronomical debate, as it was done by Welser, in 1611-1613, in the debate on sunspots between Christoph Scheiner and Galileo Galilei. Nevertheless, the split in the scholarly world between humanists and scientists proved to be so fundamental at that time, that Welser, in order to be accepted also by the mathematici, had to establish anew his renown in these circles independent of his philological achievements. At the same time, he did not undertake anything to integrate the astronomers into the humanistic res publica litteraria.

  17. SYRA3 COST Action--Microbeam radiation therapy: Roots and prospects.

    PubMed

    Bravin, Alberto; Olko, Pawel; Schültke, Elisabeth; Wilkens, Jan J

    2015-09-01

    Microbeam radiation therapy (MRT) is an irradiation modality for therapeutic purposes which uses arrays of collimated quasi parallel microbeams, each up to 100 μm wide, to deliver high radiation doses. Several studies have reported the extraordinary tolerance of normal tissues to MRT irradiation; conversely, MRT has been shown to be highly efficient on tumor growth control. The original and most widely developed application of MRT, yet in the preclinical phase, consists in using spatially fractionated X-ray beams issued from a synchrotron radiation source in the treatment of brain tumors. More recently, MRT has been tested in successful pioneering assays to reduce or interrupt seizures in preclinical models of epilepsy. The MRT concept has also been extended to proton therapy. The development of MRT towards its clinical implementation is presently driven by an EU-supported consortium of laboratories from 16 countries within the COST Action TD1205 (SYRA3). The results of the first SYRA3 workshop on "Radiation Therapy with Synchrotron Radiation: Achievements and Challenges" held in Krakow (Poland) during March 25-26 2014 are summarized in this issue with an overview presented in this paper. The papers reflect the multidisciplinary international activities of SYRA3. The topics covered in this focus issue include medical physics aspects, pre-clinical studies, clinical applications, and an industrial perspective; finally an outlook towards future prospects of compact sources and proton microbeams. PMID:26123367

  18. Retention of fluid and particles in captive tapirs (Tapirus sp.).

    PubMed

    Clauss, Marcus; Lang-Deuerling, Stefanie; Müller, Dennis W H; Kienzle, Ellen; Steuer, Patrick; Hummel, Jürgen

    2010-09-01

    The retention of ingesta in the digestive tract is a major characteristic of herbivorous animals. We measured particle and fluid mean retention times (MRT) in 13 lowland tapirs (Tapirus terrestris) and 5 Malayan tapirs (Tapirus indicus) from five zoological institutions on their usual zoo diet and 2 lowland and 4 Malayan tapirs additionally on roughage-only diets (total n of trials=24) with cobalt-EDTA as fluid and chromium-mordanted fibre (<2 mm) as particle markers. MRT for fluid and particles averaged 42+/-16 h and 55+/-18 h in lowland and 40+/-13 h and 56+/-14 h in Malayan tapirs. In a General Linear Model, neither Tapir species, body mass or diet (characterised by the proportion of roughage) was significantly related to MRT, but dry matter intake was, with a steep decline in MRT with higher intake levels. Compared to other hindgut fermenters, tapirs have a low defecation frequency, which might be linked to their comparatively low food intake. Their gastrointestinal capacity (in dry matter: 1.63+/-0.63% of body mass) is similar to that calculated for horses. A comparison of the difference in fluid and particle MRT in large hindgut fermenters (horses, rhinoceroses, elephants, and the tapirs of this study) shows that longer absolute particle MRT are linked to shorter relative fluid MRT, possibly indicating a more thorough 'washing' of particulate ingesta with digestive fluids at longer particle MRT. The only outlier to this general pattern, with an exceptionally high difference between fluid and particle MRT, indicating a particularly efficient ingesta washing, is the white rhinoceros (Ceratotherium simum). If possible, results of this study should be compared to findings in tapirs on natural diets. PMID:20363350

  19. Modified radiative transfer theory for a two-layer random medium

    NASA Technical Reports Server (NTRS)

    Zuniga, M. A.; Kong, J. A.

    1980-01-01

    Modified radiative transfer (MRT) equations appropriate for electromagnetic wave propagation in bounded random media are derived from the Bethe-Salpeter equation with the ladder approximation and the Dyson equation with the nonlinear approximation. The MRT equations are then solved with the first-order renormalization approximation to obtain analytical results for the backscattering cross sections of a two-layer random medium with arbitrary three-dimensional correlation functions. The coherent effects of the MRT theory are illustrated and comparisons are made with backscattering cross sections obtained with the first Born approximation to the wave equation.

  20. [Magnetic-resonance tomography in diagnosis of hepatopancreatoduodenal tumors].

    PubMed

    Portnoĭ, L M; Denisova, L B; Utkina, E V; Safiullina, I M; Denisov, V A; Sachechelashvili, G L

    2003-01-01

    Results of magnetic-resonance tomography (MRT) in 112 patients with diseases of hepatopancreatoduodenal zone were analyzed, 24 of them had tumors of bile ducts and pancreas. New noninvasive diagnostic method--magnetic-resonance cholangiopancreatography (MRCPG)--performed in addition to routine MRT was evaluated. The technique of MRCPG, analysis of results, manetic-resonance semiotics are presented. This method is compared with endoscopic retrograde cholangiopancreatography. It is concluded that combination of consentional MRT with MRCPG increases possibilities in diagnosis of hepatopancreatoduodenal cancers, complicated by obstructive jaundice, as a rule.

  1. Tazemetostat Rollover Study (TRuST): An Open-Label Rollover Study

    ClinicalTrials.gov

    2016-09-13

    Diffuse Large B-cell Lymphoma; Follicular Lymphoma; Malignant Rhabdoid Tumors (MRT); Rhabdoid Tumors of the Kidney (RTK); Atypical Teratoid Rhabdoid Tumors (ATRT); Synovial Sarcoma; Epitheliod Sarcoma; Mesothelioma; Advanced Solid Tumors

  2. A Phase II, Multicenter Study of the EZH2 Inhibitor Tazemetostat in Adult Subjects With INI1-Negative Tumors or Relapsed/Refractory Synovial Sarcoma

    ClinicalTrials.gov

    2016-09-20

    Malignant Rhabdoid Tumors (MRT); Rhabdoid Tumors of the Kidney (RTK); Atypical Teratoid Rhabdoid Tumors (ATRT); Selected Tumors With Rhabdoid Features; Synovial Sarcoma; INI1-negative Tumors; Malignant Rhabdoid Tumor of Ovary; Renal Medullary Carcinoma; Epithelioid Sarcoma

  3. SU-E-T-45: Antibody Mean Residence Time in Blood and Its Correlation with Protein Molecular Weight

    SciTech Connect

    Kwok, C; Williams, L

    2014-06-01

    Purpose: Animal biodistribution data are required prior to introducing a new radiopharmaceutical into clinical trials. Protein engineering, using recombinant DNA techniques can produce a large number of related (cognate) antibodies to a given molecular target. Thus, it is important that these constructs be numerically related to one another via a single criterion. In the following, we use the mean residence time (MRT) in murine blood as this criterion. Methods: Five cognate anti-CEA (Carcinoembryonic Antigen) antibodies were compared with regard to their MRT in whole blood of CEA-positive tumor-bearing (LS174T) mice. MRT was defined by blood AUC (area under the curve) divided by the initial blood uptake value; all in units of percent injected dose per gram (%ID/g). Cognates included single chain scFv (25 kDa), diabody (50 kDa), minibody (80 kDa), F(ab')2 (120 kDa), and intact (155 kDa) forms of the murine cT84.66 antibody against CEA. All were labeled with radioactive iodine. Results: The agents, in the sequence listed, exhibited MRT values of 1.16 +/- 0.01 h, 0.99 h, 5.06 +/- 0.70 h, 6.61 +/- 0.36 h, and 59.3 +/- 2.4 h respectively. Because of the monotonic nature of the sequence, a linear correlation analysis was performed between molecular weight (MW) and MRT or ln(MRT) of the 5 proteins. Probability of random correlation was 0.10 for MRT and 0.01 for ln(MRT). Conclusion: MRT values of cognate anti-CEA antibodies were found to be a monotonically increasing sequence with respect to MW. Cognate MW values correlated best to ln(MRT) of the protein species. Thus MRT was proportional to an exponential function of molecular weight. The extended intact antibody circulation time presumably reflected its relatively maximal MW. Presence of an intact FC segment on this native antibody may also have influenced these results.

  4. Immersive virtual reality platform for medical training: a "killer-application".

    PubMed

    2000-01-01

    The Medical Readiness Trainer (MRT) integrates fully immersive Virtual Reality (VR), highly advanced medical simulation technologies, and medical data to enable unprecedented medical education and training. The flexibility offered by the MRT environment serves as a practical teaching tool today and in the near future the will serve as an ideal vehicle for facilitating the transition to the next level of medical practice, i.e., telepresence and next generation Internet-based collaborative learning. PMID:10977542

  5. Internet-Enabled Audio Communication: A Richer Medium For Students Feedback?

    ERIC Educational Resources Information Center

    Johnson, Roy D.; Keil, Mark

    This study compared the effects of using voice mail (v-mail) to electronic mail (e-mail) over the Internet to provide student feedback using Media Richness Theory (MRT) and Social Presence Theory (SPT) as the theoretical framework. MRT and SPT would predict that v-mail would be perceived as higher than e-mail in media richness and social presence.…

  6. Continuous automatic classification of seismic signals of volcanic origin at Mt. Merapi, Java, Indonesia

    NASA Astrophysics Data System (ADS)

    Ohrnberger, Matthias

    2001-07-01

    performs therefore best for VTB-type events, with almost 89% recognition accuracy and 2 FA/day. Seismic signals of the MP- and Guguran-classes are more difficult to detect and classify. Around 64% of MP-events and 74% of Guguran signals are recognized correctly. The average false alarm rate for MP-events is 87 FA/day, whereas for Guguran signals 33 FA/day are obtained. However, the majority of missed events and false alarms for both MP and Guguran events are due to confusion errors between these two event classes in the recognition process. The confusion of MP and Guguran events is interpreted as being a consequence of the selected parametrization approach for the continuous seismic data streams. The observed patterns of the analyzed wavefield attributes for MP and Guguran events show a significant amount of similarity, thus providing not sufficient discriminative information for the numerical classification. The similarity of wavefield parameters obtained for seismic events of MP and Guguran type reflect the commonly observed dominance of path effects on the seismic wave propagation in volcanic environments. The recognition rates obtained for the five-day period of increasing seismicity show, that the presented DHMM-based automatic classification system is a promising approach for the difficult task of classifying volcano-seismic signals. Compared to standard signal detection algorithms, the most significant advantage of the discussed technique is, that the entire seismogram is detected and classified in a single step. Aufgrund seiner nahezu kontinuierlichen eruptiven Aktivität zählt der Merapi zu den gefährlichsten Vulkanen der Welt. Der Merapi befindet sich im Zentralteil der dicht bevölkerten Insel Java (Indonesien). Selbst kleinere Ausbrüche des Merapi stellen deswegen eine große Gefahr für die ansässige Bevölkerung in der Umgebung des Vulkans dar. Die am Merapi beobachtete enge Korrelation zwischen seismischer und vulkanischer Aktivität erlaubt es, mit

  7. Eruptive Ereignisse als Kennzeichen später Sternentwicklung

    NASA Astrophysics Data System (ADS)

    Seitter, W. C.

    Die Autorin hat mit V605 Aql ein vermutliches Bindeglied zwischen planetarischen Nebeln und Novae gefunden. Sie sucht nun nach beobachtbaren Gemeinsamkeiten der beiden Objektklassen und weiterer eruptiver Sterne.

  8. Planning combined treatments of external beam radiation therapy and molecular radiotherapy.

    PubMed

    Cremonesi, Marta; Ferrari, Mahila; Botta, Francesca; Guerriero, Francesco; Garibaldi, Cristina; Bodei, Lisa; De Cicco, Concetta; Grana, Chiara Maria; Pedroli, Guido; Orecchia, Roberto

    2014-08-01

    Molecular radiotherapy (MRT) with radiolabeled molecules has being constantly evolving, leading to notable results in cancer treatment. In some cases, the absorbed doses delivered to tumors by MRT are sufficient to obtain complete responses; in other cases, instead, to be effective, MRT needs to be combined with other therapeutic approaches. Recently, several studies proposed the combination of MRT with external beam radiation therapy (EBRT). Some describe the theoretical basis within radiobiological models, others report the results of clinical phase I-II studies aimed to assess the feasibility and tolerability. The latter includes the treatment of various tumors, such as meningiomas, paragangliomas, non-Hodgkin's lymphomas, bone, brain, hepatic, and breast lesions. The underlying principle of combined MRT and EBRT is the possibility of exploiting the full potential of each modality, given the different organs at risk. Target tissues can indeed receive a higher irradiation, while respecting the threshold limits of more than one critical tissue. Nevertheless, clinical trials are empirical and optimization is still a theoretical issue. This article describes the state of the art of combined MRT and EBRT regarding the rationale and the results of clinical studies, with special focus on the possibility of treatment improvement.

  9. Mediastinal radiation and adverse outcomes after heart transplantation.

    PubMed

    Uriel, Nir; Vainrib, Alan; Jorde, Ulrich P; Cotarlan, Vlad; Farr, Maryjane; Cheema, Faisal H; Naka, Yoshifuma; Mancini, Donna; Colombo, Paolo C

    2010-03-01

    Orthotopic heart transplantation (OHT) may represent the only treatment option for patients with end-stage cardiovascular disease due to mediastinal radiation therapy (MRT). The primary aim of this study was to evaluate the safety and efficacy of OHT in this patient population. We conducted a retrospective, single-center cohort study of patients with MRT-associated cardiovascular disease who underwent OHT between January 1987 and September 2008. Nine patients (3 men), aged 46 +/- 11 years at the time of their OHT, were identified. Time from MRT to OHT was 26 +/- 11 years. Lymphoma was the indication for MRT in all patients. Five patients had non-ischemic dilated cardiomyopathy, 2 had ischemic cardiomyopathy and 2 had constrictive pericarditis. Three patients expired in the peri-operative period, whereas another patient died 3 years post-transplant from lung carcinoma. Two additional patients developed a secondary malignancy post-transplant. Five patients are still alive at a mean follow-up of 10 +/- 8 years. Early survival rate is poor in patients who undergo OHT for MRT-associated end-stage cardiovascular disease. In addition, long-term follow-up shows an elevated incidence of malignancies. Our results raise concern about the safety and efficacy of performing OHT in patients with MRT-associated cardiovascular disease.

  10. High resolution 3D imaging of synchrotron generated microbeams

    SciTech Connect

    Gagliardi, Frank M.; Cornelius, Iwan; Blencowe, Anton; Franich, Rick D.; Geso, Moshi

    2015-12-15

    Purpose: Microbeam radiation therapy (MRT) techniques are under investigation at synchrotrons worldwide. Favourable outcomes from animal and cell culture studies have proven the efficacy of MRT. The aim of MRT researchers currently is to progress to human clinical trials in the near future. The purpose of this study was to demonstrate the high resolution and 3D imaging of synchrotron generated microbeams in PRESAGE® dosimeters using laser fluorescence confocal microscopy. Methods: Water equivalent PRESAGE® dosimeters were fabricated and irradiated with microbeams on the Imaging and Medical Beamline at the Australian Synchrotron. Microbeam arrays comprised of microbeams 25–50 μm wide with 200 or 400 μm peak-to-peak spacing were delivered as single, cross-fire, multidirectional, and interspersed arrays. Imaging of the dosimeters was performed using a NIKON A1 laser fluorescence confocal microscope. Results: The spatial fractionation of the MRT beams was clearly visible in 2D and up to 9 mm in depth. Individual microbeams were easily resolved with the full width at half maximum of microbeams measured on images with resolutions of as low as 0.09 μm/pixel. Profiles obtained demonstrated the change of the peak-to-valley dose ratio for interspersed MRT microbeam arrays and subtle variations in the sample positioning by the sample stage goniometer were measured. Conclusions: Laser fluorescence confocal microscopy of MRT irradiated PRESAGE® dosimeters has been validated in this study as a high resolution imaging tool for the independent spatial and geometrical verification of MRT beam delivery.

  11. Magneto-Rayleigh-Taylor Instability: Theory and simulation in planar and cylindrical pulsed power targets

    NASA Astrophysics Data System (ADS)

    Weis, Matthew R.

    Cylindrical liner implosions in the Magnetized Liner Inertial Fusion (MagLIF) concept are susceptible to the magneto-Rayleigh-Taylor instability (MRT). The danger of MRT enters in two phases, (1) during the main implosion, the outer surface of the liner is MRT unstable, and (2) during the short time period when the liner decelerates onto hot fuel, the inner surface becomes unstable. Growth of MRT on the outer surface may also feedthrough, which may seed the inner surface leading to high MRT growth in the second phase. If MRT growth becomes large enough, confinement of the fuel is lost. To characterize MRT we solve the linearized, ideal MHD equations in both planar and cylindrical geometries, including the presence of an axial magnetic field and the effects of sausage and kink modes (present in cylindrical coordinates only). In general, the total instability growth rates in cylindrical geometry are found to be larger than those in planar geometry. MRT and feedthrough is shown to be suppressed by strong magnetic field line bending (tension). However, for the same amount of field line bending, feedthrough is the most stabilized. Application of the planar and the cylindrical model to results from the Z-machine at Sandia National Laboratories is presented. Analytic MRT growth rates for a typical magnetized MagLIF-like implosion show the kink mode to be the fastest growing early and very late in the liner implosion (during deceleration). 1D HYDRA MHD simulations are used to generate realistic, evolving profiles (in density, pressure, and magnetic field) during the implosion from which instantaneous growth rates can be computed exactly, using either the planar or cylindrical analytic formulae developed in this thesis. Sophisticated 2D HYDRA MHD simulations were also performed to compare with the analytic theory and experimental results. In 2D, highly compressed axial magnetic fields can reduce the growth of perturbations at the fuel/liner interface during the implosion

  12. Pilot study for compact microbeam radiation therapy using a carbon nanotube field emission micro-CT scanner

    SciTech Connect

    Hadsell, Mike Cao, Guohua; Zhang, Jian; Burk, Laurel; Schreiber, Torsten; Lu, Jianping; Zhou, Otto; Schreiber, Eric; Chang, Sha

    2014-06-15

    Purpose: Microbeam radiation therapy (MRT) is defined as the use of parallel, microplanar x-ray beams with an energy spectrum between 50 and 300 keV for cancer treatment and brain radiosurgery. Up until now, the possibilities of MRT have mainly been studied using synchrotron sources due to their high flux (100s Gy/s) and approximately parallel x-ray paths. The authors have proposed a compact x-ray based MRT system capable of delivering MRT dose distributions at a high dose rate. This system would employ carbon nanotube (CNT) field emission technology to create an x-ray source array that surrounds the target of irradiation. Using such a geometry, multiple collimators would shape the irradiation from this array into multiple microbeams that would then overlap or interlace in the target region. This pilot study demonstrates the feasibility of attaining a high dose rate and parallel microbeam beams using such a system. Methods: The microbeam dose distribution was generated by our CNT micro-CT scanner (100μm focal spot) and a custom-made microbeam collimator. An alignment assembly was fabricated and attached to the scanner in order to collimate and superimpose beams coming from different gantry positions. The MRT dose distribution was measured using two orthogonal radiochromic films embedded inside a cylindrical phantom. This target was irradiated with microbeams incident from 44 different gantry angles to simulate an array of x-ray sources as in the proposed compact CNT-based MRT system. Finally, phantom translation in a direction perpendicular to the microplanar beams was used to simulate the use of multiple parallel microbeams. Results: Microbeams delivered from 44 gantry angles were superimposed to form a single microbeam dose distribution in the phantom with a FWHM of 300μm (calculated value was 290 μm). Also, during the multiple beam simulation, a peak to valley dose ratio of ∼10 was found when the phantom translation distance was roughly 4x the beam width

  13. Communicating astronomy in a small island state: The unique role of the Mauritius Radio Telescope

    NASA Astrophysics Data System (ADS)

    Saddul-Hauzaree, S.

    2008-06-01

    The Mauritius Radio Telescope (MRT) is a 2 km x 1 km T-shaped aperture synthesis array that can generate radio images of the southern sky at 151.6 MHz. The sky surveyed can be in the declination range of -70o to -10o. It is located at Bras d'Eau, northeast of Mauritius at latitude 20oS and longitude 60oE. The MRT is a joint project of the University of Mauritius, the Indian Institute of Astrophysics and the Raman Research Institute. One of the main objectives of the MRT is to generate public interest in astronomy. Thus, it is involved in a wide range of onsite outreach activities for young school children. More mature students visiting the telescope learn about sky observation with a radio telescope, get to explore some sets of data, interact with the scientific personnel, get the opportunity to have hands-on experience with image manipulation and can ask a lot of questions on astronomy. This poster gives an overview of the Mauritius Radio Telescope and the attempts of MRT ito communicate astronomy to students as a process and not just as a vast expanse of knowledge. The challenges and dilemmas faced by MRT in conveying astronomy to the general public in a small island state are investigated and presented.

  14. Effects of microbeam radiation therapy on normal and tumoral blood vessels.

    PubMed

    Bouchet, Audrey; Serduc, Raphäel; Laissue, Jean Albert; Djonov, Valentin

    2015-09-01

    Microbeam radiation therapy (MRT) is a new form of preclinical radiotherapy using quasi-parallel arrays of synchrotron X-ray microbeams. While the deposition of several hundred Grays in the microbeam paths, the normal brain tissues presents a high tolerance which is accompanied by the permanence of apparently normal vessels. Conversely, the efficiency of MRT on tumor growth control is thought to be related to a preferential damaging of tumor blood vessels. The high resistance of the healthy vascular network was demonstrated in different animal models by in vivo biphoton microscopy, magnetic resonance imaging, and histological studies. While a transient increase in permeability was shown, the structure of the vessels remained intact. The use of a chick chorioallantoic membrane at different stages of development showed that the damages induced by microbeams depend on vessel maturation. In vivo and ultrastructural observations showed negligible effects of microbeams on the mature vasculature at late stages of development; nevertheless a complete destruction of the immature capillary plexus was found in the microbeam paths. The use of MRT in rodent models revealed a preferential effect on tumor vessels. Although no major modification was observed in the vasculature of normal brain tissue, tumors showed a denudation of capillaries accompanied by transient increased permeability followed by reduced tumor perfusion and finally, a decrease in number of tumor vessels. Thus, MRT is a very promising treatment strategy with pronounced tumor control effects most likely based on the anti-vascular effects of MRT.

  15. Coupling of sausage, kink, and magneto-Rayleigh-Taylor instabilities in a cylindrical liner

    NASA Astrophysics Data System (ADS)

    Weis, M. R.; Zhang, P.; Lau, Y. Y.; Schmit, P. F.; Peterson, K. J.; Hess, M.; Gilgenbach, R. M.

    2015-03-01

    This paper analyzes the coupling of magneto-Rayleigh-Taylor (MRT), sausage, and kink modes in an imploding cylindrical liner, using ideal MHD. A uniform axial magnetic field of arbitrary value is included in each region: liner, its interior, and its exterior. The dispersion relation is solved exactly, for arbitrary radial acceleration (-g), axial wavenumber (k), azimuthal mode number (m), liner aspect ratio, and equilibrium quantities in each region. For small k, a positive g (inward radial acceleration in the lab frame) tends to stabilize the sausage mode, but destabilize the kink mode. For large k, a positive g destabilizes both the kink and sausage mode. Using the 1D-HYDRA simulation results for an equilibrium model that includes a pre-existing axial magnetic field and a preheated fuel, we identify several stages of MRT-sausage-kink mode evolution. We find that the m = 1 kink-MRT mode has a higher growth rate at the initial stage and stagnation stage of the implosion, and that the m = 0 sausage-MRT mode dominates at the main part of implosion. This analysis also sheds light on a puzzling feature in Harris' classic paper of MRT [E. G. Harris, Phys. Fluids 5, 1057 (1962)]. An attempt is made to interpret the persistence of the observed helical structures [Awe et al., Phys. Rev. Lett. 111, 235005 (2013)] in terms of non-axisymmetric eigenmode.

  16. Coupling of sausage, kink, and magneto-Rayleigh-Taylor instabilities in a cylindrical liner

    SciTech Connect

    Weis, M. R.; Zhang, P.; Lau, Y. Y. Gilgenbach, R. M.; Schmit, P. F.; Peterson, K. J.; Hess, M.

    2015-03-15

    This paper analyzes the coupling of magneto-Rayleigh-Taylor (MRT), sausage, and kink modes in an imploding cylindrical liner, using ideal MHD. A uniform axial magnetic field of arbitrary value is included in each region: liner, its interior, and its exterior. The dispersion relation is solved exactly, for arbitrary radial acceleration (-g), axial wavenumber (k), azimuthal mode number (m), liner aspect ratio, and equilibrium quantities in each region. For small k, a positive g (inward radial acceleration in the lab frame) tends to stabilize the sausage mode, but destabilize the kink mode. For large k, a positive g destabilizes both the kink and sausage mode. Using the 1D-HYDRA simulation results for an equilibrium model that includes a pre-existing axial magnetic field and a preheated fuel, we identify several stages of MRT-sausage-kink mode evolution. We find that the m = 1 kink-MRT mode has a higher growth rate at the initial stage and stagnation stage of the implosion, and that the m = 0 sausage-MRT mode dominates at the main part of implosion. This analysis also sheds light on a puzzling feature in Harris' classic paper of MRT [E. G. Harris, Phys. Fluids 5, 1057 (1962)]. An attempt is made to interpret the persistence of the observed helical structures [Awe et al., Phys. Rev. Lett. 111, 235005 (2013)] in terms of non-axisymmetric eigenmode.

  17. Simulation and mitigation of the magneto-Rayleigh-Taylor instabilities in Z-pinch gas discharge extreme ultraviolet plasma radiation sources

    SciTech Connect

    Huang, B.; Tomizuka, T.; Xie, B.; Sakai, Y.; Zhu, Q.; Song, I.; Okino, A.; Xiao, F.; Watanabe, M.; Hotta, E.

    2013-11-15

    The development and use of a single-fluid two-temperature approximated 2-D Magneto-Hydrodynamics code is reported. Z-pinch dynamics and the evolution of Magneto-Rayleigh-Taylor (MRT) instabilities in a gas jet type Extreme Ultraviolet (EUV) source are investigated with this code. The implosion and stagnation processes of the Z-pinch dynamics and the influence of initial perturbations (single mode, multi- mode, and random seeds) on MRT instability are discussed in detail. In the case of single mode seeds, the simulation shows that the growth rates for mm-scale wavelengths up to 4 mm are between 0.05 and 0.065 ns{sup −1}. For multi-mode seeds, the mode coupling effect leads to a series of other harmonics, and complicates MRT instability evolution. For perturbation by random seeds, the modes evolve to longer wavelengths and finally converge to a mm-scale wavelength approximately 1 mm. MRT instabilities can also alter the pinch stagnation state and lead to temperature and density fluctuations along the Z axis, which eventually affects the homogeneity of the EUV radiation output. Finally, the simulation results are related to experimental results to discuss the mitigations of MRT instability.

  18. Multiple-relaxation-time lattice Boltzmann modeling of incompressible flows in porous media

    NASA Astrophysics Data System (ADS)

    Liu, Qing; He, Ya-Ling

    2015-07-01

    In this paper, a two-dimensional eight-velocity multiple-relaxation-time (MRT) lattice Boltzmann (LB) model is proposed for incompressible porous flows at the representative elementary volume scale based on the Brinkman-Forchheimer-extended Darcy model. In the model, the porosity is included into the pressure-based equilibrium moments, and the linear and nonlinear drag forces of the porous matrix are incorporated into the model by adding a forcing term to the MRT-LB equation in the moment space. Through the Chapman-Enskog analysis, the incompressible generalized Navier-Stokes equations can be recovered. Numerical simulations of several typical porous flows are carried out to validate the present MRT-LB model. It is found that the present numerical results agree well with the analytical solutions and/or other numerical results reported in the literature.

  19. Electrothermal instability growth in magnetically driven pulsed power liners

    SciTech Connect

    Peterson, Kyle J.; Sinars, Daniel B.; Yu, Edmund P.; Herrmann, Mark C.; Cuneo, Michael E.; Slutz, Stephen A.; Smith, Ian C.; Atherton, Briggs W.; Knudson, Marcus D.; Nakhleh, Charles

    2012-09-15

    This paper explores the role of electro-thermal instabilities on the dynamics of magnetically accelerated implosion systems. Electro-thermal instabilities result from non-uniform heating due to temperature dependence in the conductivity of a material. Comparatively little is known about these types of instabilities compared to the well known Magneto-Rayleigh-Taylor (MRT) instability. We present simulations that show electrothermal instabilities form immediately after the surface material of a conductor melts and can act as a significant seed to subsequent MRT instability growth. We also present the results of several experiments performed on Sandia National Laboratories Z accelerator to investigate signatures of electrothermal instability growth on well characterized initially solid aluminum and copper rods driven with a 20 MA, 100 ns risetime current pulse. These experiments show excellent agreement with electrothermal instability simulations and exhibit larger instability growth than can be explained by MRT theory alone.

  20. [The importance of computed tomography and magnetic resonance tomography in shockwave cholelithotripsy].

    PubMed

    Golder, W A; Tempel, U; Gmeinwieser, J

    1989-01-01

    With shockwave-lithotripsy a new method of therapy has been introduced, whose efficiency is essentially determined by that of the accompanying imaging diagnostics. This poses several new problems for the diagnostic radiologist. While sonography and conventional cholegraphy have an important place in connection with shockwave-lithotripsy, the role of computed tomography (CT) and magnetic resonance tomography (MRT) has not yet been established. According to our experiences and experimental data pre-interventional CT improves the accuracy for measurements of the calcium content of concrements and gives the best survey on the topography of the upper abdomen of patients with biliary concrements. MRT before lithotripsy does not yield important additional information. Applied after intervention it at least equals CT. Besides localization and description of the diseased gall-bladder the detection of complications with CT and MRT is one of the tasks of the radiologist in connection with shockwave-lithotripsy.

  1. Deadlock checking for one-place unbounded Petri nets based on modified reachability trees.

    PubMed

    Ding, ZhiJun; Jiang, ChangJun; Zhou, MengChu

    2008-06-01

    A deadlock-checking approach for one-place unbounded Petri nets is presented based on modified reachability trees (MRTs). An MRT can provide some useful information that is lost in a finite reachability tree, owing to MRT's use of the expression a + bn(i) rather than symbol omega to represent the value of the components of a marking. The information is helpful to property analysis of unbounded Petri nets. For the deadlock-checking purpose, this correspondence paper classifies full conditional nodes in MRT into two types: true and fake ones. Then, an algorithm is proposed to determine whether a full conditional node is true or not. Finally, a necessary and sufficient condition of deadlocks is presented. Examples are given to illustrate the method.

  2. So-called `relaxation' mode located at 0.1 cm-1 in the low-frequency Raman spectra of ethylene glycol - acetone mixtures

    NASA Astrophysics Data System (ADS)

    Amo, Y.; Kameda, Y.; Usuki, T.

    2016-05-01

    Low frequency Raman spectra of ethylene glycol(EG) and acetone mixtures are investigated by high-resolution double monochrometer. A broad peak located at 0.1 cm-1 in susceptibility spectra is compared with the dielectric loss spectra. Both Raman relaxation time(τMRT1) and dielectric relaxation time(τD1) are determined by the model fitting method. The ratio τMRT1/τD1 does not depend on static dielectric constant of mixtures and is almost constant, ≈3.2, from 1.0 (pure EG) to 0.3 mole fraction. This result indicates that both τMRT1 and τD1 are determined by the same molecular dynamics.

  3. Microwave remote sensing of a two-layer random medium

    NASA Technical Reports Server (NTRS)

    Tsang, L.; Kong, J. A.

    1976-01-01

    A two-variable expansion technique is used to solve for the mean Green's. function from the Dyson equation under the nonlinear approximation. The Bethe-Salpeter equation then gives rise to a set of modified radiative transfer (MRT) equations which accommodate coherent effects essential to bounded media. It is found that the nonlinear approximation, instead of the more popular bilocal approximation, should be used for the case of bounded media. The two approximations yield identical results for unbounded media. The MRT equations are then solved for a two-layer random medium. The MRT equations give rise to simple and useful solutions which are applicable to both active and passive microwave remote sensing.

  4. Setting the chaperonin timer: A two-stroke, two-speed, protein machine

    PubMed Central

    Grason, John P.; Gresham, Jennifer S.; Lorimer, George H.

    2008-01-01

    In a study of the timing mechanism of the chaperonin nanomachine we show that the hemicycle time (HCT) is determined by the mean residence time (MRT) of GroES on the cis ring of GroEL. In turn, this is governed by allosteric interactions within the trans ring of GroEL. Ligands that enhance the R (relaxed) state (residual ADP, the product of the previous hemicycle, and K+) extend the MRT and the HCT, whereas ligands that enhance the T (taut) state (unfolded substrate protein, SP) decrease the MRT and the HCT. In the absence of SP, the chaperonin machine idles in the resting state, but in the presence of SP it operates close to the speed limit, set by the rate of ATP hydrolysis by the cis ring. Thus, the conformational states of the trans ring largely control the speed of the complete chaperonin cycle. PMID:18988739

  5. Calculations of first passage time of delayed tree-like networks

    NASA Astrophysics Data System (ADS)

    Wang, Shuai; Sun, Weigang; Zheng, Song

    2015-10-01

    In this paper, we study random walks in a family of delayed tree-like networks controlled by two network parameters, where an immobile trap is located at the initial node. The novel feature of this family of networks is that the existing nodes have a time delay to give birth to new nodes. By the self-similar network structure, we obtain exact solutions of three types of first passage time (FPT) measuring the efficiency of random walks, which includes the mean receiving time (MRT), mean sending time (MST) and mean first passage time (MFPT). The obtained results show that the MRT, MST and MFPT increase with the network parameters. We further show that the values of MRT, MST and MFPT are much shorter than the nondelayed counterpart, implying that the efficiency of random walks in delayed trees is much higher.

  6. 2D radiation-magnetohydrodynamic simulations of SATURN imploding Z-pinches

    SciTech Connect

    Hammer, J.H.; Eddleman, J.L.; Springer, P.T.

    1995-11-06

    Z-pinch implosions driven by the SATURN device at Sandia National Laboratory are modeled with a 2D radiation magnetohydrodynamic (MHD) code, showing strong growth of magneto-Rayleigh Taylor (MRT) instability. Modeling of the linear and nonlinear development of MRT modes predicts growth of bubble-spike structures that increase the time span of stagnation and the resulting x-ray pulse width. Radiation is important in the pinch dynamics keeping the sheath relatively cool during the run-in and releasing most of the stagnation energy. The calculations give x-ray pulse widths and magnitudes in reasonable agreement with experiments, but predict a radiating region that is too dense and radially localized at stagnation. We also consider peaked initial density profiles with constant imploding sheath velocity that should reduce MRT instability and improve performance. 2D krypton simulations show an output x-ray power > 80 TW for the peaked profile.

  7. Studies on Morphological and Physio-Ecological Variations of the Reniform Nematode, Rotylenchulus reniformis Linford and Oliveira, 1940 with an Emphasis on Differential Geographical Distribution of Amphimictic and Parthenogenetic Populations in Japan

    PubMed Central

    Nakasono, Kazutoshi

    2004-01-01

    The geographical distribution and polymorphism in morphological and biological characters of the reniform nematode, Rotylenchulus reniformis, in Japan were studied. The northern limit of habitat of this nematode was found on the 14 °C isothermal line of annual average-air temperature. Three morphologically different groups were ascertained which corresponded to three biological types based on male frequency. Incidence of males was consistent within populations and was not affected by environmental factors. Sexual attraction of males by females indicated reproductive isolation between the male-numerous type (MNT) and male-rare type (MRT) or male-absent type (MAT). Reproduction was amphimictic in the MNT and parthenogenetic in the MRT and MAT. Larval development in both MRT and MAT, but not that of MNT popula-tions, was inhibited at 34 °C. Differences in host preference were also observed among populations. PMID:19262821

  8. Prevalence of bovine brucellosis in organized dairy farms, using milk ELISA, in quetta city, balochistan, pakistan.

    PubMed

    Shafee, Muhammad; Rabbani, Masood; Sheikh, Ali Ahmad; Ahmad, Mansoor Din; Razzaq, Abdul

    2011-01-24

    A total of 200 milk samples from cattle (n = 86) and buffalo (n = 114) were evaluated using milk ring test (MRT) and indirect enzyme-linked immunosorbent assay (i-ELISA). The overall prevalence was found to be 3% and 8.5% in cattle and buffaloes using MRT and i-ELISA, respectively. The prevalence was 4.6% and 1.7% in cattle and buffalo using MRT, respectively, while i-ELISA exhibited 20% and 0% in cattle and buffalo, respectively. The prevalence was higher in government dairy farm, compared to privately owned dairy farm. This paper points out an alarming situation in the target area with respect to the public health significance.

  9. [Magnetic-resonance tomography in differential diagnosis of brain lesions in demyelinating and systemic autoimmune diseases].

    PubMed

    Totolian, N A

    2005-01-01

    An aim of the study was to establish MRT signs that may be useful for differential diagnosis of multiple sclerosis (MS). Three groups of patients have been examined: 300 patients with MS, 35 with demyelinating diseases (acute disseminated encephalomyelitis, neuromyelitis optica--Devic's syndrome); 90 patients with systemic autoimmune diseases (systemic lupus erythematosus, primary antiphospholipid syndrome, sclerodermatitis, Sjugren's syndrome, autoimmune thyroiditis, vasculitis and vasculopathy). Classification of MRT syndromes in MS and their frequency are presented: syndrome of chronic inflammatory demyelination (79%), syndrome of acute inflammatory demyelination (9%), syndrome of multifocal degenerative leucoencephalopathy (8%), syndrome of combined multifocal diffusive leucoencephalopathy (4%). The similarity and differences in MRT semiotics of the above diseases and MS are described.

  10. Exercise-mediated vasodilation in human obesity and metabolic syndrome: effect of acute ascorbic acid infusion

    PubMed Central

    Limberg, Jacqueline K.; Kellawan, J. Mikhail; Harrell, John W.; Johansson, Rebecca E.; Eldridge, Marlowe W.; Proctor, Lester T.; Sebranek, Joshua J.

    2014-01-01

    We tested the hypothesis that infusion of ascorbic acid (AA), a potent antioxidant, would alter vasodilator responses to exercise in human obesity and metabolic syndrome (MetSyn). Forearm blood flow (FBF, Doppler ultrasound) was measured in lean, obese, and MetSyn adults (n = 39, 32 ± 2 yr). A brachial artery catheter was inserted for blood pressure monitoring and local infusion of AA. FBF was measured during dynamic handgrip exercise (15% maximal effort) with and without AA infusion. To account for group differences in blood pressure and forearm size, and to assess vasodilation, forearm vascular conductance (FVC = FBF/mean arterial blood pressure/lean forearm mass) was calculated. We examined the time to achieve steady-state FVC (mean response time, MRT) and the rise in FVC from rest to steady-state exercise (Δ, exercise − rest) before and during acute AA infusion. The MRT (P = 0.26) and steady-state vasodilator responses to exercise (ΔFVC, P = 0.31) were not different between groups. Intra-arterial infusion of AA resulted in a significant increase in plasma total antioxidant capacity (174 ± 37%). AA infusion did not alter MRT or steady-state FVC in any group (P = 0.90 and P = 0.85, respectively). Interestingly, higher levels of C-reactive protein predicted longer MRT (r = 0.52, P < 0.01) and a greater reduction in MRT with AA infusion (r = −0.43, P = 0.02). We concluded that AA infusion during moderate-intensity, rhythmic forearm exercise does not alter the time course or magnitude of exercise-mediated vasodilation in groups of young lean, obese, or MetSyn adults. However, systemic inflammation may limit the MRT to exercise, which can be improved with AA. PMID:25038148

  11. p16INK4A and p14ARF Tumor Suppressor Pathways Are Deregulated in Malignant Rhabdoid Tumors

    PubMed Central

    Venneti, Sriram; Le, Paul; Martinez, Daniel; Eaton, Katherine W.; Shyam, Nikhil; Jordan-Sciutto, Kelly L.; Pawel, Bruce; Biegel, Jaclyn A.; Judkins, Alexander R.

    2011-01-01

    Malignant rhabdoid tumors (MRT) are aggressive tumors associated with mutations in the SMARCB1 gene. In experimental systems, the loss of SMARCB1 is hypothesized to alter p16INK4A pathways resulting in repression of tumor suppressors. To determine whether these pathways are deregulated in human MRT, we used immunohistochemistry on tissue microarrays to evaluate p16INK4A/E2F1/RB and p14ARF/MDM2/p53 pathways in 25 atypical teratoid/ rhabdoid tumors (AT/RT) and 11 non-CNS MRT. p16INK4A was negative or showed focal weak expression. The p16INK4A downstream targets CDK4/cyclin D1/ppRB were variably expressed at moderate to low levels; E2F1 was negative. Unexpectedly, p14ARF expression was seen in many cases, which correlated positively with p53 and inversely with MDM2 immunostaining in AT/RT. TP53 mutational analysis in 19/25 AT/RT and 8/11 non-CNS MRT cases showed point mutations in only 3 AT/RT cases, suggesting that p53 expression was driven mainly by p14ARF. Finally, nucleophosmin, a protein that stabilizes p53, was positive in the majority of cases and colocalized with p53. Together, these data suggest that in MRT there is deregulation of not only p16INK4A, but also the p14ARF pathway. These results provide insights into cell cycle deregulation in the pathogenesis of human MRT and may aid in the design and evaluation of potential therapies for these tumors. PMID:21666498

  12. 21-cm Observations with the Morehead Radio Telescope: Involving Undergraduates in Observing Programs

    NASA Astrophysics Data System (ADS)

    Malphrus, B. K.; Combs, M. S.; Kruth, J.

    2000-12-01

    Herein we report astronomical observations made by undergraduate students with the Morehead Radio Telescope (MRT). The MRT, located at Morehead State University, Morehead, Kentucky, is small aperture (44-ft.) instrument designed by faculty, students, and industrial partners to provide a research instrument and active laboratory for undergraduate astronomy, physics, pre-engineering, and computer science students. Small aperture telescopes like the MRT have numerous advantages as active laboratories and as research instruments. The benefits to students are based upon a hands-on approach to learning concepts in astrophysics and engineering. Students are provided design and research challenges and are allowed to pursue their own solutions. Problem-solving abilities and research design skills are cultivated by this approach. Additionally, there are still contributions that small aperture centimeter-wave instruments can make. The MRT operates over a 6 MHz bandwidth centered at 1420 MHz (21-cm), which corresponds to the hyperfine transition of atomic hydrogen (HI). The HI spatial distribution and flux density associated with cosmic phenomena can be observed and mapped. The dynamics and kinematics of celestial objects can be investigated by observing over a range of frequencies (up to 2.5 MHz) with a 2048-channel back-end spectrometer, providing up to 1 KHz frequency resolution. The sensitivity and versatility of the telescope design facilitate investigation of a wide variety of cosmic phenomena, including supernova remnants, emission and planetary nebulae, extended HI emission from the Milky Way, quasars, radio galaxies, and the sun. Student observations of galactic sources herein reported include Taurus A, Cygnus X, and the Rosette Nebula. Additionally, we report observations of extragalactic phenomena, including Cygnus A, 3C 147, and 3C 146. These observations serve as a performance and capability test-bed of the MRT. In addition to the astronomical results of these

  13. Preferential Effect of Synchrotron Microbeam Radiation Therapy on Intracerebral 9L Gliosarcoma Vascular Networks

    SciTech Connect

    Bouchet, Audrey; Lemasson, Benjamin; Le Duc, Geraldine; Maisin, Cecile; Braeuer-Krisch, Elke; Siegbahn, Erik Albert; Renaud, Luc; Khalil, Enam; Remy, Chantal; Poillot, Cathy; Bravin, Alberto; Laissue, Jean A.; Barbier, Emmanuel L.; Serduc, Raphael

    2010-12-01

    Purpose: Synchrotron microbeam radiation therapy (MRT) relies on spatial fractionation of the incident photon beam into parallel micron-wide beams. Our aim was to analyze the effects of MRT on normal brain and 9L gliosarcoma tissues, particularly on blood vessels. Methods and Materials: Responses to MRT (two arrays, one lateral, one anteroposterior (2 x 400 Gy), intersecting orthogonally in the tumor region) were studied during 6 weeks using MRI, immunohistochemistry, and vascular endothelial growth factor Western blot. Results: MRT increased the median survival time of irradiated rats (x3.25), significantly increased blood vessel permeability, and inhibited tumor growth; a cytotoxic effect on 9L cells was detected 5 days after irradiation. Significant decreases in tumoral blood volume fraction and vessel diameter were measured from 8 days after irradiation, due to loss of endothelial cells in tumors as detected by immunochemistry. Edema was observed in the normal brain exposed to both crossfired arrays about 6 weeks after irradiation. This edema was associated with changes in blood vessel morphology and an overexpression of vascular endothelial growth factor. Conversely, vascular parameters and vessel morphology in brain regions exposed to one of the two arrays were not damaged, and there was no loss of vascular endothelia. Conclusions: We show for the first time that preferential damage of MRT to tumor vessels versus preservation of radioresistant normal brain vessels contributes to the efficient palliation of 9L gliosarcomas in rats. Molecular pathways of repair mechanisms in normal and tumoral vascular networks after MRT may be essential for the improvement of such differential effects on the vasculature.

  14. Mathematical modelling of digesta passage rate, mean retention time and in vivo apparent digestibility of two different lengths of hay and big-bale grass silage in ponies.

    PubMed

    Moore-Colyer, M J S; Morrow, H J; Longland, A C

    2003-07-01

    Welsh-cross pony geldings (about 300 kg live weight) were used in a 4x4 Latin square experiment to determine the rate of passage and apparent digestibility of unchopped big-bale grass silage (BBL), chopped big-bale grass silage (BBS), unchopped grass hay (HL) and chopped grass hay (HS) offered at approximately 15 g/kg live weight per d. On day 1 of collection weeks, ponies were fed 85 g ytterbium chloride hexahydrate-marked feed 1.5 h after the morning meal. Total faecal collections commenced 8 h later and continued for 168 h. Apparent digestibilities of feed DM, organic matter (OM), crude protein (CP, Nx6.25), acid-detergent fibre (ADF) and neutral-detergent fibre (NDF) were also determined. Faecal excretion data were subjected to the models of Pond et al. (1988) and digesta mean retention time (MRT) calculated from these models and using the algebraic method of Thielmans et al. (1978). Silage had significantly (P<0.05) higher digestibilities of DM, OM, CP, ADF and NDF than hay; however, chop length had no effect. All the models of Pond et al. (1988) accurately described (R(2)>0.8) the pattern of faecal marker excretion. MRT of BBL (29.0 h)>BBS(27 h)>HS and HL (26 h). Compartmental analysis using the G3 model of Pond et al. (1988) showed BBL and HS diets had longer MRT in the time-dependent compartment, whereas BBS and HL had longer MRT in the time-independent compartment. Results from this experiment indicate that BBL and BBS are readily accepted and digested by ponies. While Yb is a successful external marker for determining total tract MRT and for modelling faecal excretion curves in horses, the results did not allow any definite conclusions to be drawn on digesta MRT within the different compartments of the equid gut.

  15. Absorbed dose-to-water protocol applied to synchrotron-generated x-rays at very high dose rates

    NASA Astrophysics Data System (ADS)

    Fournier, P.; Crosbie, J. C.; Cornelius, I.; Berkvens, P.; Donzelli, M.; Clavel, A. H.; Rosenfeld, A. B.; Petasecca, M.; Lerch, M. L. F.; Bräuer-Krisch, E.

    2016-07-01

    Microbeam radiation therapy (MRT) is a new radiation treatment modality in the pre-clinical stage of development at the ID17 Biomedical Beamline of the European synchrotron radiation facility (ESRF) in Grenoble, France. MRT exploits the dose volume effect that is made possible through the spatial fractionation of the high dose rate synchrotron-generated x-ray beam into an array of microbeams. As an important step towards the development of a dosimetry protocol for MRT, we have applied the International Atomic Energy Agency’s TRS 398 absorbed dose-to-water protocol to the synchrotron x-ray beam in the case of the broad beam irradiation geometry (i.e. prior to spatial fractionation into microbeams). The very high dose rates observed here mean the ion recombination correction factor, k s , is the most challenging to quantify of all the necessary corrections to apply for ionization chamber based absolute dosimetry. In the course of this study, we have developed a new method, the so called ‘current ramping’ method, to determine k s for the specific irradiation and filtering conditions typically utilized throughout the development of MRT. Using the new approach we deduced an ion recombination correction factor of 1.047 for the maximum ESRF storage ring current (200 mA) under typical beam spectral filtering conditions in MRT. MRT trials are currently underway with veterinary patients at the ESRF that require additional filtering, and we have estimated a correction factor of 1.025 for these filtration conditions for the same ESRF storage ring current. The protocol described herein provides reference dosimetry data for the associated Treatment Planning System utilized in the current veterinary trials and anticipated future human clinical trials.

  16. High resolution X-ray fluorescence imaging for a microbeam radiation therapy treatment planning system

    NASA Astrophysics Data System (ADS)

    Chtcheprov, Pavel; Inscoe, Christina; Burk, Laurel; Ger, Rachel; Yuan, Hong; Lu, Jianping; Chang, Sha; Zhou, Otto

    2014-03-01

    Microbeam radiation therapy (MRT) uses an array of high-dose, narrow (~100 μm) beams separated by a fraction of a millimeter to treat various radio-resistant, deep-seated tumors. MRT has been shown to spare normal tissue up to 1000 Gy of entrance dose while still being highly tumoricidal. Current methods of tumor localization for our MRT treatments require MRI and X-ray imaging with subject motion and image registration that contribute to the measurement error. The purpose of this study is to develop a novel form of imaging to quickly and accurately assist in high resolution target positioning for MRT treatments using X-ray fluorescence (XRF). The key to this method is using the microbeam to both treat and image. High Z contrast media is injected into the phantom or blood pool of the subject prior to imaging. Using a collimated spectrum analyzer, the region of interest is scanned through the MRT beam and the fluorescence signal is recorded for each slice. The signal can be processed to show vascular differences in the tissue and isolate tumor regions. Using the radiation therapy source as the imaging source, repositioning and registration errors are eliminated. A phantom study showed that a spatial resolution of a fraction of microbeam width can be achieved by precision translation of the mouse stage. Preliminary results from an animal study showed accurate iodine profusion, confirmed by CT. The proposed image guidance method, using XRF to locate and ablate tumors, can be used as a fast and accurate MRT treatment planning system.

  17. Absorbed dose-to-water protocol applied to synchrotron-generated x-rays at very high dose rates.

    PubMed

    Fournier, P; Crosbie, J C; Cornelius, I; Berkvens, P; Donzelli, M; Clavel, A H; Rosenfeld, A B; Petasecca, M; Lerch, M L F; Bräuer-Krisch, E

    2016-07-21

    Microbeam radiation therapy (MRT) is a new radiation treatment modality in the pre-clinical stage of development at the ID17 Biomedical Beamline of the European synchrotron radiation facility (ESRF) in Grenoble, France. MRT exploits the dose volume effect that is made possible through the spatial fractionation of the high dose rate synchrotron-generated x-ray beam into an array of microbeams. As an important step towards the development of a dosimetry protocol for MRT, we have applied the International Atomic Energy Agency's TRS 398 absorbed dose-to-water protocol to the synchrotron x-ray beam in the case of the broad beam irradiation geometry (i.e. prior to spatial fractionation into microbeams). The very high dose rates observed here mean the ion recombination correction factor, k s , is the most challenging to quantify of all the necessary corrections to apply for ionization chamber based absolute dosimetry. In the course of this study, we have developed a new method, the so called 'current ramping' method, to determine k s for the specific irradiation and filtering conditions typically utilized throughout the development of MRT. Using the new approach we deduced an ion recombination correction factor of 1.047 for the maximum ESRF storage ring current (200 mA) under typical beam spectral filtering conditions in MRT. MRT trials are currently underway with veterinary patients at the ESRF that require additional filtering, and we have estimated a correction factor of 1.025 for these filtration conditions for the same ESRF storage ring current. The protocol described herein provides reference dosimetry data for the associated Treatment Planning System utilized in the current veterinary trials and anticipated future human clinical trials. PMID:27366861

  18. WE-G-BRE-01: A High Power Nanotube X-Ray Microbeam Irradiator for Preclinical Brain Tumor Treatment

    SciTech Connect

    Chtcheprov, P; Inscoe, C; Zhang, L; Lu, J; Zhou, O; Chang, S; Sprenger, F; Laganis, P

    2014-06-15

    Purpose: Microbeam radiation therapy (MRT) is a new type of cancer treatment undergoing studies at various synchrotron facilities. The principle of MRT is using arrays of microscopically small, low-energy X-radiation for the treatment of various radio-resistant, deep-seated tumors. Our motivation is to develop a compact and inexpensive image guided MRT irradiator to use in the research lab setting. After a successful initial demonstration, here we report a second generation carbon nanotube (CNT) cathode based MRT tube, capable of producing multiple microbeam lines with an anticipated dose rate of 11 Gy/min per line. Methods: The system uses multiple line CNT source arrays to generate multiple focal lines on the anode. The increase in dose-rate, compared to our first generation system, is achieved by increasing the operating voltage from 160 kVp to 225kVp, adding multiple simultaneous focal lines on the anode, and a more efficient cooling mechanism using a 6kW oil-cooled anode. Results: This work will present the design and development process, challenges and solutions to meeting operating specifications, and the final design of the tube and collimator, along with optimization and stabilization of its use. A detailed characterization of its capabilities will be included with a comprehensive measurement of its X-ray focal line dimensions, an evaluation of its collimator alignment and microbeam dimensions, and phantom-based quantification of its dosimetric output. Conclusion: The development of a second generation, compact, multiple line MRT device using carbon nanotube (CNT) cathode based X-ray technology and a novel oil cooled anode design is presented here. With this new source, we are capable of delivering a total microbeam radiation dose comparable to the low end of the synchrotron based MRT systems for small animal brain tumor models.

  19. Kommunikation mit Mitarbeitern

    NASA Astrophysics Data System (ADS)

    Spychala, Anne; Fleischmann, Jürgen

    Kommunikation ist der Austausch von Nachrichten und Informationen zwischen Mitarbeitern eines Unternehmens (O'Hair et al. 1997). Dieser Austausch kann persönlich, aber z.B. auch per Telefon, E-Mail oder durch Computersysteme erfolgen. In diesem Kapitel betrachten wir die persönliche Kommunikation zwischen Vorgesetzten und Mitarbeitern. Zur persönlichen Kommunikation mit Mitarbeitern zählen sowohl formelle Gespräche mit Mitarbeitern als auch eher informelle Gespräche zwischen Tür und Angel. Die Gespräche können dabei mit einzelnen Mitarbeitern (z.B. jährliches Mitarbeitergespräch) oder mit Gruppen von Mitarbeitern (z.B. regelmäßige Projekt- oder Teambesprechungen) stattfinden.

  20. Modified radiative transfer theory for a two-layer anisotropic random medium

    NASA Technical Reports Server (NTRS)

    Lee, J. K.; Kong, J. A.

    1988-01-01

    The modified radiative transfer (MRT) equations which describe propagation and scattering of the electromagnetic field intensity in a layered anisotropic random medium are derived from the Bethe-Salpeter equation with the ladder approximation and the Dyson equation with the nonlinear approximation. The extinction matrices and scattering phase matrices for both mean and incoherent field intensities are obtained. Backscattering enhancement is observed due to the spatial coherent effect between upward and downward propagating waves. It also occurs for the half-space case, because of coupling between ordinary and extraordinary waves. The depolarization effect is predicted in the first-order renormalization approximation to the MRT equation.

  1. Comparison of different methods of estimating the mean radiant temperature in outdoor thermal comfort studies.

    PubMed

    Krüger, E L; Minella, F O; Matzarakis, A

    2014-10-01

    Correlations between outdoor thermal indices and the calculated or measured mean radiant temperature T(mrt) are in general of high importance because of the combined effect on human energy balance in outdoor spaces. The most accurate way to determine T(mrt) is by means of integral radiation measurements, i.e. measuring the short- and long-wave radiation from six directions using pyranometers and pyrgeometers, an expensive and not always an easily available procedure. Some studies use globe thermometers combined with air temperature and wind speed sensors. An alternative way to determine T(mrt) is based on output from the RayMan model from measured data of incoming global radiation and morphological features of the monitoring site in particular sky view factor (SVF) data. The purpose of this paper is to compare different methods to assess the mean radiant temperature T(mrt) in terms of differences to a reference condition (T(mrt) calculated from field measurements) and to resulting outdoor comfort levels expressed as PET and UTCI values. The T(mrt) obtained from field measurements is a combination of air temperature, wind speed and globe temperature data according to the forced ventilation formula of ISO 7726 for data collected in Glasgow, UK. Four different methods were used in the RayMan model for T(mrt) calculations: input data consisting exclusively of data measured at urban sites; urban data excluding solar radiation, estimated SVF data and solar radiation data measured at a rural site; urban data excluding solar radiation with SVF data for each site; urban data excluding solar radiation and including solar radiation at the rural site taking no account of SVF information. Results show that all methods overestimate T(mrt) when compared to ISO calculations. Correlations were found to be significant for the first method and lower for the other three. Results in terms of comfort (PET, UTCI) suggest that reasonable estimates could be made based on global radiation

  2. Familial handedness and spatial ability: a study with Chinese students aged 14-24.

    PubMed

    Li, Chieh; Zhu, Wenbin; Nuttall, Ronald L

    2003-04-01

    This study tested Annett's right-shift theory on spatial ability with two samples from China. The Vandenberg Mental Rotation Test (MRT), Edinburgh Handedness Inventory, and Family Handedness Questionnaire were administered to 266 high school students and 297 undergraduates. We found very few r++ or r-- among Chinese students. Most Chinese are either moderately right-handed or ambidextrous. Consistent with Casey's finding, we found using different methods to classify handedness leads to different conclusions. However, we did not find the effect of familial handedness that Casey found. Visual strategy is related to success on the MRT but handedness is not.

  3. NYS: Tackling the Issue of High Users of Healthcare.

    PubMed

    Zucker, Howard A

    2014-01-01

    A disproportionate amount of healthcare costs in developed nations are attributed to a small percentage of high-needs patients. New York is no exception. Addressing the needs of this subgroup of Medicaid patients was part of reforms begun in 2011 with the creation of the Medicaid Redesign Team (MRT). The MRT successfully adopted 78 revisions to the Medicaid program. Some broad reforms target all Medicaid enrollees. The state also invested in two specific programs to meet the needs of high users: supportive housing and Health Homes. Close monitoring of both programs is underway and over time, will reveal the value of these two initiatives. PMID:25880864

  4. Investigating the Spatial Abilities of Students Taking Physics in Community College

    NASA Astrophysics Data System (ADS)

    Hossu, M. R.; Cid, X.; Lopez, R.

    2010-10-01

    Two independent tests that involve spatial visualization abilities, the PFT (Paper Folding Test) and the MRT (Mental Rotation Test) were given to different sections of introductory level physics students. The results show a strong correlation between the results of the two tests regardless of the different level of mathematics used in instruction (algebra or calculus). A statistically significant difference was found for both tests between the summer semester students (mostly 4-year university students) and the fall semester students (mostly community college students). No correlation was found between the PFT or MRT and FCI (Force Concept Inventory).

  5. Time-dependent renormalized Redfield theory II for off-diagonal transition in reduced density matrix

    NASA Astrophysics Data System (ADS)

    Kimura, Akihiro

    2016-09-01

    In our previous letter (Kimura, 2016), we constructed time-dependent renormalized Redfield theory (TRRT) only for diagonal transition in a reduced density matrix. In this letter, we formulate the general expression for off-diagonal transition in the reduced density matrix. We discuss the applicability of TRRT by numerically comparing the dependencies on the energy gap of the exciton relaxation rate by using the TRRT and the modified Redfield theory (MRT). In particular, we roughly show that TRRT improves MRT for the detailed balance about the excitation energy transfer reaction.

  6. The Development and Testing of Guidelines for Designing School Classrooms to Maximize Hearing Conditions and Provide for Effective Noise Control. Final Report.

    ERIC Educational Resources Information Center

    Kingsbury, H. F.; Strumpf, F. M.

    Speech intelligibility was tested in three classroom type spaces, one of 700 square feet, and two of 200 square feet, using student listeners and recorded test material. One of the latter two classrooms was fully carpeted. The test material used was Modified Rhyme Test (MRT) tapes, presented via tape reproducer and loudspeaker. Also investigated…

  7. Quantitative and Qualitative Change in Children's Mental Rotation Performance

    ERIC Educational Resources Information Center

    Geiser, Christian; Lehmann, Wolfgang; Corth, Martin; Eid, Michael

    2008-01-01

    This study investigated quantitative and qualitative changes in mental rotation performance and solution strategies with a focus on sex differences. German children (N = 519) completed the Mental Rotations Test (MRT) in the 5th and 6th grades (interval: one year; age range at time 1: 10-11 years). Boys on average outperformed girls on both…

  8. Promise for the Future: An Evaluation of the Texas Master Reading Teacher Program.

    ERIC Educational Resources Information Center

    Hall, Linda DeZell; O'Neill, Kevin J.; Hasbrouck, Jan E.; Parker, Richard I.

    In 1999 the Texas Legislature provided for the creation of the Master Reading Teacher (MRT) Certificate to address several issues. MRTs primary duties are to: serve as reading teachers; consult with and mentor other teachers; and provide research-based information and training. In September 2001 the Texas Education Agency asked Dr. Jan Hasbrouck…

  9. Influence of ground surface characteristics on the mean radiant temperature in urban areas.

    PubMed

    Lindberg, Fredrik; Onomura, Shiho; Grimmond, C S B

    2016-09-01

    The effect of variations in land cover on mean radiant temperature (T mrt ) is explored through a simple scheme developed within the radiation model SOLWEIG. Outgoing longwave radiation is parameterised using surface temperature observations on a grass and an asphalt surface, whereas outgoing shortwave radiation is modelled through variations in albedo for the different surfaces. The influence of ground surface materials on T mrt is small compared to the effects of shadowing. Nevertheless, altering ground surface materials could contribute to a reduction in T mrt to reduce the radiant load during heat-wave episodes in locations where shadowing is not an option. Evaluation of the new scheme suggests that despite its simplicity it can simulate the outgoing fluxes well, especially during sunny conditions. However, it underestimates at night and in shadowed locations. One grass surface used to develop the parameterisation, with very different characteristics compared to an evaluation grass site, caused T mrt to be underestimated. The implications of using high temporal resolution (e.g. 15 minutes) meteorological forcing data under partly cloudy conditions are demonstrated even for fairly proximal sites. PMID:26852384

  10. MRI Based Diagnostics for Temperature Measurements in Turbulent Flows

    NASA Astrophysics Data System (ADS)

    Burton, Lauren Sascha; Elkins, Christopher J.; Eaton, John K.

    2014-11-01

    Accurate modeling of the thermal diffusion in the complex turbulent flows related to cooling high temperature gas turbine blades is critical to optimize the performance and predict the lifetime of the blades. Magnetic Resonance Imaging (MRI) techniques for temperature measurement in simple but related flows are being developed in an effort to obtain full field thermal measurements to better understand diffusion processes and support the development of more accurate computational models in these flows. Magnetic Resonance Thermometry (MRT) utilizes the temperature dependence of the hydrogen proton resonant frequency (PRF) in water. MRT is now routinely used to measure tissue temperatures during medical procedures, and a few previous studies have made velocity and temperature measurements in turbulent pipe flows. In this study, MRT is applied to the flow of a heated single hole film cooling jet (Reynolds number 3000) inclined at 30 degrees injected into a cold developing turbulent channel flow (Reynolds number 25,000 based on bulk velocity and channel height.) The jet fluid temperature is 30 degrees Celsius above the temperature in the channel. The temperature measurements compare well to previously published results for measured passive scalar concentration in the same flow although the temperature measurements show higher uncertainties of 5--10 % of the temperature difference. Techniques for reducing this uncertainty will be presented as well as procedures for applying MRT to quantify the turbulent heat transfer coefficient in turbulent internal flows.

  11. Multi-rate time stepping schemes for hydro-geomechanical model for subsurface methane hydrate reservoirs

    NASA Astrophysics Data System (ADS)

    Gupta, Shubhangi; Wohlmuth, Barbara; Helmig, Rainer

    2016-05-01

    We present an extrapolation-based semi-implicit multi-rate time stepping (MRT) scheme and a compound-fast MRT scheme for a naturally partitioned, multi-time-scale hydro-geomechanical hydrate reservoir model. We evaluate the performance of the two MRT methods compared to an iteratively coupled solution scheme and discuss their advantages and disadvantages. The performance of the two MRT methods is evaluated in terms of speed-up and accuracy by comparison to an iteratively coupled solution scheme. We observe that the extrapolation-based semi-implicit method gives a higher speed-up but is strongly dependent on the relative time scales of the latent (slow) and active (fast) components. On the other hand, the compound-fast method is more robust and less sensitive to the relative time scales, but gives lower speed up as compared to the semi-implicit method, especially when the relative time scales of the active and latent components are comparable.

  12. Physiologically gated micro-beam radiation therapy using electronically controlled field emission x-ray source array

    NASA Astrophysics Data System (ADS)

    Chtcheprov, Pavel; Hadsell, Michael; Burk, Laurel; Ger, Rachel; Zhang, Lei; Yuan, Hong; Lee, Yueh Z.; Chang, Sha; Lu, Jianping; Zhou, Otto

    2013-03-01

    Micro-beam radiation therapy (MRT) uses parallel planes of high dose narrow (10-100 um in width) radiation beams separated by a fraction of a millimeter to treat cancerous tumors. This experimental therapy method based on synchrotron radiation has been shown to spare normal tissue at up to 1000Gy of entrance dose while still being effective in tumor eradication and extending the lifetime of tumor-bearing small animal models. Motion during the treatment can result in significant movement of micro beam positions resulting in broader beam width and lower peak to valley dose ratio (PVDR), and thus can reduce the effectiveness of the MRT. Recently we have developed the first bench-top image guided MRT system for small animal treatment using a high powered carbon nanotube (CNT) x-ray source array. The CNT field emission x-ray source can be electronically synchronized to an external triggering signal to enable physiologically gated firing of x-ray radiation to minimize motion blurring. Here we report the results of phantom study of respiratory gated MRT. A simulation of mouse breathing was performed using a servo motor. Preliminary results show that without gating the micro beam full width at tenth maximum (FWTM) can increase by 70% and PVDR can decrease up to 50%. But with proper gating, both the beam width and PVDR changes can be negligible. Future experiments will involve irradiation of mouse models and comparing histology stains between the controls and the gated irradiation.

  13. Early and Late Inhibitions Elicited by a Peripheral Visual Cue on Manual Response to a Visual Target: Are They Based on Cartesian Coordinates?

    ERIC Educational Resources Information Center

    Gawryszewski, Luiz G.; Carreiro, Luiz Renato R.; Magalhaes, Fabio V.

    2005-01-01

    A non-informative cue (C) elicits an inhibition of manual reaction time (MRT) to a visual target (T). We report an experiment to examine if the spatial distribution of this inhibitory effect follows Polar or Cartesian coordinate systems. C appeared at one out of 8 isoeccentric (7[degrees]) positions, the C-T angular distances (in polar…

  14. SOLWEIG 1.0--modelling spatial variations of 3D radiant fluxes and mean radiant temperature in complex urban settings.

    PubMed

    Lindberg, Fredrik; Holmer, Björn; Thorsson, Sofia

    2008-09-01

    The mean radiant temperature, T(mrt), which sums up all shortwave and longwave radiation fluxes (both direct and reflected) to which the human body is exposed is one of the key meteorological parameters governing human energy balance and the thermal comfort of man. In this paper, a new radiation model (SOLWEIG 1.0), which simulates spatial variations of 3D radiation fluxes and T(mrt) in complex urban settings, is presented. The T(mrt) is derived by modelling shortwave and longwave radiation fluxes in six directions (upward, downward and from the four cardinal points) and angular factors. The model requires a limited number of inputs, such as direct, diffuse and global shortwave radiation, air temperature, relative humidity, urban geometry and geographical information (latitude, longitude and elevation). The model was evaluated using 7 days of integral radiation measurements at two sites with different building geometries--a large square and a small courtyard in Göteborg, Sweden (57 degrees N)--across different seasons and in various weather conditions. The evaluation reveals good agreement between modelled and measured values of T(mrt), with an overall good correspondence of R (2) = 0.94, (p < 0.01, RMSE = 4.8 K). SOLWEIG 1.0 is still under development. Future work will incorporate a vegetation scheme, as well as an improvement of the estimation of fluxes from the four cardinal points.

  15. Blocks and Bodies: Sex Differences in a Novel Version of the Mental Rotations Test

    PubMed Central

    Alexander, Gerianne M.; Evardone, Milagros

    2009-01-01

    A novel version of the Mental Rotations Test (MRT) that alternated the standard block figures with three-dimensional human figures was administered to 99 men and 129 women. Women and men differed predictably in their retrospective reports of childhood play and digit ratios, a putative measure of prenatal androgen action. Compared to the block figure items, human figure items on the modified MRT were associated with an improvement in performance in both sexes. However, consistent with the study hypothesis, the enhancing effect of the human figure condition on performance as measured by conventional scores was smaller in men compared to women and not at all evident in men when performance was measured by ratio scores. A closer inspection of the human figures effects on test scores showed performance in women improved for both male and female figure items. In contrast, relative to scores on block figure items, performance in men improved when stimuli were male figures but did not improve when stimuli were female figures. These results add to the evidence that the magnitude of sex differences in scores on the MRT may vary according to the test content and item properties. The findings suggest that online measures of cognitive processing in response to different classes of test stimuli (e.g., animate vs. inanimate objects, self-relevant vs. neutral stimuli) may prove useful in research aimed at understanding the hormonal and social factors contributing to the sex difference in performance on the MRT. PMID:18036595

  16. Progesterone and mental rotation task: is there any effect?

    PubMed

    Noreika, Donatas; Griškova-Bulanova, Inga; Alaburda, Aidas; Baranauskas, Mindaugas; Grikšienė, Ramunė

    2014-01-01

    Mental rotation task (MRT) incorporates elements of spatial abilities, important in many professions, with people of both genders involved. Importantly, these are the areas where spatial tasks might be performed for long time periods; thus adverse effects of mental fatigue are highly unwanted. Substantial variation of MRT performance in relation to estrogen levels has been observed in many studies, whereas the role of progesterone remains elusive. Here we aimed to elucidate the effect of progesterone level on the long-duration (1.5 hours) performance of MRT. We included three groups of subjects: a group of males as a control, a group of females in their follicular phase (low progesterone) and a group of females in their luteal phase (high progesterone), MRT accuracy and response time, subjective fatigue ratings and cardiovascular measures together with 17 β -estradiol and progesterone concentrations were analyzed. We found that subjective ratings of fatigue increased, performance accuracy increased, and mean response times decreased during the task in all groups. Females in luteal phase were significantly slower not only than men, but also than females in their follicular phase. An increase in subjective fatigue ratings was positively related to progesterone level-at higher progesterone levels, females felt more tired. PMID:24818150

  17. Relationship between Morphofunctional Changes in Open Traumatic Brain Injury and the Severity of Brain Damage in Rats.

    PubMed

    Shakova, F M; Barskov, I V; Gulyaev, M V; Prokhorenko, S V; Romanova, G A; Grechko, A V

    2016-07-01

    A correlation between the severity of morphofunctional disturbances and the volume of brain tissue injury determined by MRT was demonstrated on the model of open traumatic brain injury in rats. A relationship between the studied parameters (limb placing and beam walking tests and histological changes) and impact force (the height of load fell onto exposed brain surface) was revealed.

  18. Magnetic resonance thermometry at 7T for real-time monitoring and correction of ultrasound induced mild hyperthermia.

    PubMed

    Fite, Brett Z; Liu, Yu; Kruse, Dustin E; Caskey, Charles F; Walton, Jeffrey H; Lai, Chun-Yen; Mahakian, Lisa M; Larrat, Benoit; Dumont, Erik; Ferrara, Katherine W

    2012-01-01

    While Magnetic Resonance Thermometry (MRT) has been extensively utilized for non-invasive temperature measurement, there is limited data on the use of high field (≥7T) scanners for this purpose. MR-guided Focused Ultrasound (MRgFUS) is a promising non-invasive method for localized hyperthermia and drug delivery. MRT based on the temperature sensitivity of the proton resonance frequency (PRF) has been implemented in both a tissue phantom and in vivo in a mouse Met-1 tumor model, using partial parallel imaging (PPI) to speed acquisition. An MRgFUS system capable of delivering a controlled 3D acoustic dose during real time MRT with proportional, integral, and derivative (PID) feedback control was developed and validated. Real-time MRT was validated in a tofu phantom with fluoroptic temperature measurements, and acoustic heating simulations were in good agreement with MR temperature maps. In an in vivo Met-1 mouse tumor, the real-time PID feedback control is capable of maintaining the desired temperature with high accuracy. We found that real time MR control of hyperthermia is feasible at high field, and k-space based PPI techniques may be implemented for increasing temporal resolution while maintaining temperature accuracy on the order of 1°C.

  19. Influence of ground surface characteristics on the mean radiant temperature in urban areas

    NASA Astrophysics Data System (ADS)

    Lindberg, Fredrik; Onomura, Shiho; Grimmond, C. S. B.

    2016-09-01

    The effect of variations in land cover on mean radiant temperature ( T mrt ) is explored through a simple scheme developed within the radiation model SOLWEIG. Outgoing longwave radiation is parameterised using surface temperature observations on a grass and an asphalt surface, whereas outgoing shortwave radiation is modelled through variations in albedo for the different surfaces. The influence of ground surface materials on T mrt is small compared to the effects of shadowing. Nevertheless, altering ground surface materials could contribute to a reduction in T mrt to reduce the radiant load during heat-wave episodes in locations where shadowing is not an option. Evaluation of the new scheme suggests that despite its simplicity it can simulate the outgoing fluxes well, especially during sunny conditions. However, it underestimates at night and in shadowed locations. One grass surface used to develop the parameterisation, with very different characteristics compared to an evaluation grass site, caused T mrt to be underestimated. The implications of using high temporal resolution (e.g. 15 minutes) meteorological forcing data under partly cloudy conditions are demonstrated even for fairly proximal sites.

  20. Individual Differences in the Mental Rotation Skills of Turkish Prospective Teachers

    ERIC Educational Resources Information Center

    Turgut, Melih

    2015-01-01

    This study investigated the effects of gender, academic performance and preschool education on mental rotation skills among Turkish prospective teachers. A total of 525 undergraduate students (364 female) from a government university located in western Turkey completed the Mental Rotation Test (MRT). A three-way [2 (gender) × 5 (academic…

  1. The Effects of Written Language Awareness on First Grade Reading Achievement.

    ERIC Educational Resources Information Center

    Taylor, Nancy E.; Blum, Irene H.

    A battery of four reading readiness assessment tasks was administered to 267 first grade students to determine if the tasks predicted reading achievement as well as the Metropolitan Readiness Test (MRT). The four tasks, which were the best predictors in a previous study of seven readiness tasks, were the aural word boundaries task, the…

  2. Genome-Wide Profiles of Extra-cranial Malignant Rhabdoid Tumors Reveal Heterogeneity and Dysregulated Developmental Pathways | Office of Cancer Genomics

    Cancer.gov

    Malignant rhabdoid tumors (MRTs) are rare lethal tumors of childhood that most commonly occur in the kidney and brain. MRTs are driven by SMARCB1 loss, but the molecular consequences of SMARCB1 loss in extra-cranial tumors have not been comprehensively described and genomic resources for analyses of extra-cranial MRT are limited.

  3. Enhancement of Spatial Ability in Girls in a Single-Sex Environment through Spatial Experience and the Impact on Information Seeking

    ERIC Educational Resources Information Center

    Swarlis, Linda L.

    2008-01-01

    The test scores of spatial ability for women lag behind those of men in many spatial tests. On the Mental Rotations Test (MRT), a significant gender gap has existed for over 20 years and continues to exist. High spatial ability has been linked to efficiencies in typical computing tasks including Web and database searching, text editing, and…

  4. Experimental Investigation of the Effects of an Axial Magnetic Field on the Magneto-Rayleigh-Taylor Instability in Ablating Planar Foils

    NASA Astrophysics Data System (ADS)

    Yager-Elorriaga, D. A.; Patel, S. G.; Steiner, A. M.; Jordan, N. M.; Weiss, M. R.; Gilgenbach, R. M.; Lau, Y. Y.

    2014-10-01

    Experiments are underway to study the effects an axial magnetic field on the magneto-Rayleigh-Taylor instability (MRT) in ablating planar foils on the 1-MA LTD at the Michigan Accelerator for Inductive Z-pinch Experiments (MAIZE) facility at the University of Michigan. For 600 kA drive current, a 15 T axial magnetic field is produced using helical return current posts. During the current pulse, the magnetic field may diffuse into the foil, creating a sheared magnetic field along with the possibility of shear stabilization of the MRT instability. Theoretical investigation at UM has shown that a sheared azimuthal magnetic field coupled with an axial magnetic field reduces the MRT growth rate in general. In order to study this effect, the amount of magnetic shear is controlled by offsetting the initial position of the foil. A 775 nm Ti:sapphire laser will be used to shadowgraph the foil in order to measure the MRT growth rate. By comparing these results to previous experiments at UM, the effects of magnetic shear and an axial magnetic field will be determined. This work was supported by US DoE. S.G. Patel and A.M. Steiner supported by NPSC funded by Sandia. D.A. Yager-Elorriaga supported by NSF fellowship Grant DGE 1256260.

  5. Leaf-level nitrogen use efficiency: definition and importance.

    PubMed

    Hirose, Tadaki

    2012-07-01

    Nitrogen use efficiency (NUE) has been widely used to study the relationship between nitrogen uptake and dry mass production in the plant. As a subsystem of plant nitrogen use efficiency (NUE), I have defined leaf-level NUE as the surplus production (gross production minus leaf respiration) per unit amount of nitrogen allocated to the leaf, with factorization into leaf nitrogen productivity (NP) and mean residence time of leaf nitrogen (MRT). These concepts were applied to two herbaceous stands: a perennial Solidago altissima stand and an annual Amaranthus patulus stand. S. altissima had more than three times higher leaf NUE than A. patulus due to nearly three times longer MRT of leaf N. In both species, NUE and NP were higher at the leaf level than at the plant level, because most leaf N is involved directly in the photosynthetic activity and because leaf surplus production is higher than the plant net production. MRT was longer at the plant level. The more than twice as long MRT at the plant level as at the leaf level in S. altissima was due to a large contribution of nitrogen storage belowground in the winter in this species. Thus, comparisons between a perennial and an annual system and between plant- and leaf-level NUE with their components revealed the importance of N allocation, storage, recycling, and turnover of organs for leaf photosynthetic production and plant dry mass growth. PMID:22179330

  6. Restless Mind, Restless Body

    ERIC Educational Resources Information Center

    Seli, Paul; Carriere, Jonathan S. A.; Thomson, David R.; Cheyne, James Allan; Martens, Kaylena A. Ehgoetz; Smilek, Daniel

    2014-01-01

    In the present work, we investigate the hypothesis that failures of task-related executive control that occur during episodes of mind wandering are associated with an increase in extraneous movements (fidgeting). In 2 studies, we assessed mind wandering using thought probes while participants performed the metronome response task (MRT), which…

  7. Synchrotron Radiation Therapy from a Medical Physics point of view

    NASA Astrophysics Data System (ADS)

    Prezado, Y.; Adam, J. F.; Berkvens, P.; Martinez-Rovira, I.; Fois, G.; Thengumpallil, S.; Edouard, M.; Vautrin, M.; Deman, P.; Bräuer-Krisch, E.; Renier, M.; Elleaume, H.; Estève, F.; Bravin, A.

    2010-07-01

    Synchrotron radiation (SR) therapy is a promising alternative to treat brain tumors, whose management is limited due to the high morbidity of the surrounding healthy tissues. Several approaches are being explored by using SR at the European Synchrotron Radiation Facility (ESRF), where three techniques are under development Synchrotron Stereotactic Radiation Therapy (SSRT), Microbeam Radiation Therapy (MRT) and Minibeam Radiation Therapy (MBRT). The sucess of the preclinical studies on SSRT and MRT has paved the way to clinical trials currently in preparation at the ESRF. With this aim, different dosimetric aspects from both theoretical and experimental points of view have been assessed. In particular, the definition of safe irradiation protocols, the beam energy providing the best balance between tumor treatment and healthy tissue sparing in MRT and MBRT, the special dosimetric considerations for small field dosimetry, etc will be described. In addition, for the clinical trials, the definition of appropiate dosimetry protocols for patients according to the well established European Medical Physics recommendations will be discussed. Finally, the state of the art of the MBRT technical developments at the ESRF will be presented. In 2006 A. Dilmanian and collaborators proposed the use of thicker microbeams (0.36-0.68 mm). This new type of radiotherapy is the most recently implemented technique at the ESRF and it has been called MBRT. The main advantage of MBRT with respect to MRT is that it does not require high dose rates. Therefore it can be more easily applied and extended outside synchrotron sources in the future.

  8. Synchrotron Radiation Therapy from a Medical Physics point of view

    SciTech Connect

    Prezado, Y.; Berkvens, P.; Braeuer-Krisch, E.; Renier, M.; Bravin, A.; Adam, J. F.; Martinez-Rovira, I.; Fois, G.; Thengumpallil, S.; Edouard, M.; Deman, P.; Vautrin, M.

    2010-07-23

    Synchrotron radiation (SR) therapy is a promising alternative to treat brain tumors, whose management is limited due to the high morbidity of the surrounding healthy tissues. Several approaches are being explored by using SR at the European Synchrotron Radiation Facility (ESRF), where three techniques are under development Synchrotron Stereotactic Radiation Therapy (SSRT), Microbeam Radiation Therapy (MRT) and Minibeam Radiation Therapy (MBRT).The sucess of the preclinical studies on SSRT and MRT has paved the way to clinical trials currently in preparation at the ESRF. With this aim, different dosimetric aspects from both theoretical and experimental points of view have been assessed. In particular, the definition of safe irradiation protocols, the beam energy providing the best balance between tumor treatment and healthy tissue sparing in MRT and MBRT, the special dosimetric considerations for small field dosimetry, etc will be described. In addition, for the clinical trials, the definition of appropiate dosimetry protocols for patients according to the well established European Medical Physics recommendations will be discussed. Finally, the state of the art of the MBRT technical developments at the ESRF will be presented. In 2006 A. Dilmanian and collaborators proposed the use of thicker microbeams (0.36-0.68 mm). This new type of radiotherapy is the most recently implemented technique at the ESRF and it has been called MBRT. The main advantage of MBRT with respect to MRT is that it does not require high dose rates. Therefore it can be more easily applied and extended outside synchrotron sources in the future.

  9. Targeted magnetic delivery and tracking of cells using a magnetic resonance imaging system.

    PubMed

    Riegler, Johannes; Wells, Jack A; Kyrtatos, Panagiotis G; Price, Anthony N; Pankhurst, Quentin A; Lythgoe, Mark F

    2010-07-01

    The success of cell therapies depends on the ability to deliver the cells to the site of injury. Targeted magnetic cell delivery is an emergent technique for localised cell transplantation therapy. The use of permanent magnets limits such a treatment to organs close to the body surface or an implanted magnetic source. A possible alternative method for magnetic cell delivery is magnetic resonance targeting (MRT), which uses magnetic field gradients inherent to all magnetic resonance imaging system, to steer ferromagnetic particles to their target region. In this study we have assessed the feasibility of such an approach for cell targeting, using a range of flow rates and different super paramagnetic iron oxide particles in a vascular bifurcation phantom. Using MRT we have demonstrated that 75% of labelled cells could be guided within the vascular bifurcation. Furthermore we have demonstrated the ability to image the labelled cells before and after magnetic targeting, which may enable interactive manipulation and assessment of the distribution of cellular therapy. This is the first demonstration of cellular MRT and these initial findings support the potential value of MRT for improved targeting of intravascular cell therapies.

  10. Passage rates in poultry digestion using stable isotope markers and INAA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A method has been developed for the study of passage rates and mean residence times (MRT) of test rations through the gastrointestinal tracts of layer hens. The use of rare earth elements as stable indigestible markers monitored by neutron activation analysis has been previously demonstrated in num...

  11. On the Relationship between Solution Strategies in Two Mental Rotation Tasks

    ERIC Educational Resources Information Center

    Janssen, Anne B.; Geiser, Christian

    2010-01-01

    Individual differences in solution strategies have frequently been reported for different measures of mental rotation (MR) ability. In the present study (N=346 German students), we investigated the relationship between solution strategies on two tests commonly used to identify different patterns of strategies: the Mental Rotations Test (MRT;…

  12. Medical Readers' Theater: Relevance to Geriatrics Medical Education

    ERIC Educational Resources Information Center

    Shapiro, Johanna; Cho, Beverly

    2011-01-01

    Medical Readers' Theater (MRT) is an innovative and simple way of helping medical students to reflect on difficult-to-discuss topics in geriatrics medical education, such as aging stereotypes, disability and loss of independence, sexuality, assisted living, relationships with adult children, and end-of-life issues. The authors describe a required…

  13. Primary Mental Abilities and Metropolitan Readiness Tests as Predictors of Achievement in the First Primary Year.

    ERIC Educational Resources Information Center

    University City School District, MO.

    The prediction of achievement provides teachers with necessary information to help children attain optimal achievement. If some skill prerequistites to learning which are not fully developed can be identified and strengthened, higher levels of achievement may result. The Metropolitan Readiness Tests (MRT) are routinely given to all University City…

  14. Discrete effect on the halfway bounce-back boundary condition of multiple-relaxation-time lattice Boltzmann model for convection-diffusion equations.

    PubMed

    Cui, Shuqi; Hong, Ning; Shi, Baochang; Chai, Zhenhua

    2016-04-01

    In this paper, we will focus on the multiple-relaxation-time (MRT) lattice Boltzmann model for two-dimensional convection-diffusion equations (CDEs), and analyze the discrete effect on the halfway bounce-back (HBB) boundary condition (or sometimes called bounce-back boundary condition) of the MRT model where three different discrete velocity models are considered. We first present a theoretical analysis on the discrete effect of the HBB boundary condition for the simple problems with a parabolic distribution in the x or y direction, and a numerical slip proportional to the second-order of lattice spacing is observed at the boundary, which means that the MRT model has a second-order convergence rate in space. The theoretical analysis also shows that the numerical slip can be eliminated in the MRT model through tuning the free relaxation parameter corresponding to the second-order moment, while it cannot be removed in the single-relaxation-time model or the Bhatnagar-Gross-Krook model unless the relaxation parameter related to the diffusion coefficient is set to be a special value. We then perform some simulations to confirm our theoretical results, and find that the numerical results are consistent with our theoretical analysis. Finally, we would also like to point out the present analysis can be extended to other boundary conditions of lattice Boltzmann models for CDEs.

  15. Fibroblast Growth Factor Receptors as Novel Therapeutic Targets in SNF5-Deleted Malignant Rhabdoid Tumors

    PubMed Central

    Wöhrle, Simon; Jagani, Zainab; Thuery, Anne; Bauer-Probst, Beatrice; Reimann, Flavia; Stamm, Christelle; Pornon, Astrid; Romanet, Vincent; Guagnano, Vito; Brümmendorf, Thomas; Sellers, William R.; Hofmann, Francesco; Roberts, Charles W. M.; Graus Porta, Diana

    2013-01-01

    Malignant rhabdoid tumors (MRTs) are aggressive pediatric cancers arising in brain, kidney and soft tissues, which are characterized by loss of the tumor suppressor SNF5/SMARCB1. MRTs are poorly responsive to chemotherapy and thus a high unmet clinical need exists for novel therapies for MRT patients. SNF5 is a core subunit of the SWI/SNF chromatin remodeling complex which affects gene expression by nucleosome remodeling. Here, we report that loss of SNF5 function correlates with increased expression of fibroblast growth factor receptors (FGFRs) in MRT cell lines and primary tumors and that re-expression of SNF5 in MRT cells causes a marked repression of FGFR expression. Conversely, siRNA-mediated impairment of SWI/SNF function leads to elevated levels of FGFR2 in human fibroblasts. In vivo, treatment with NVP-BGJ398, a selective FGFR inhibitor, blocks progression of a murine MRT model. Hence, we identify FGFR signaling as an aberrantly activated oncogenic pathway in MRTs and propose pharmacological inhibition of FGFRs as a potential novel clinical therapy for MRTs. PMID:24204904

  16. Discrete effect on the halfway bounce-back boundary condition of multiple-relaxation-time lattice Boltzmann model for convection-diffusion equations.

    PubMed

    Cui, Shuqi; Hong, Ning; Shi, Baochang; Chai, Zhenhua

    2016-04-01

    In this paper, we will focus on the multiple-relaxation-time (MRT) lattice Boltzmann model for two-dimensional convection-diffusion equations (CDEs), and analyze the discrete effect on the halfway bounce-back (HBB) boundary condition (or sometimes called bounce-back boundary condition) of the MRT model where three different discrete velocity models are considered. We first present a theoretical analysis on the discrete effect of the HBB boundary condition for the simple problems with a parabolic distribution in the x or y direction, and a numerical slip proportional to the second-order of lattice spacing is observed at the boundary, which means that the MRT model has a second-order convergence rate in space. The theoretical analysis also shows that the numerical slip can be eliminated in the MRT model through tuning the free relaxation parameter corresponding to the second-order moment, while it cannot be removed in the single-relaxation-time model or the Bhatnagar-Gross-Krook model unless the relaxation parameter related to the diffusion coefficient is set to be a special value. We then perform some simulations to confirm our theoretical results, and find that the numerical results are consistent with our theoretical analysis. Finally, we would also like to point out the present analysis can be extended to other boundary conditions of lattice Boltzmann models for CDEs. PMID:27176432

  17. Relationship between Morphofunctional Changes in Open Traumatic Brain Injury and the Severity of Brain Damage in Rats.

    PubMed

    Shakova, F M; Barskov, I V; Gulyaev, M V; Prokhorenko, S V; Romanova, G A; Grechko, A V

    2016-07-01

    A correlation between the severity of morphofunctional disturbances and the volume of brain tissue injury determined by MRT was demonstrated on the model of open traumatic brain injury in rats. A relationship between the studied parameters (limb placing and beam walking tests and histological changes) and impact force (the height of load fell onto exposed brain surface) was revealed. PMID:27496035

  18. Rehabilitation of aphasia: application of melodic-rhythmic therapy to Italian language.

    PubMed

    Cortese, Maria Daniela; Riganello, Francesco; Arcuri, Francesco; Pignataro, Luigina Maria; Buglione, Iolanda

    2015-01-01

    Aphasia is a complex disorder, frequent after stroke (with an incidence of 38%), with a detailed pathophysiological characterization. Effective approaches are crucial for devising an efficient rehabilitative strategy, in order to address the everyday life and professional disability. Several rehabilitative procedures are based on psycholinguistic, cognitive, psychosocial or pragmatic approaches, including amongst those with a neurobehavioral approach the Melodic Intonation Therapy (MIT). Van Eeckhout's adaptation of MIT to French language (Melodic-Rhythmic Therapy: MRT) has implemented the training strategy by adding a rhythmic structure reproducing French prosody. The purpose of this study was to adapt MRT rehabilitation procedures to Italian language and to verify its efficacy in a group of six chronic patients (five males) with severe non-fluent aphasia and without specific aphasic treatments during the previous 9 months. The patients were treated 4 days a week for 16 weeks, with sessions of 30-40 min. They were assessed 6 months after the end of the treatment (follow-up). The patients showed a significant improvement at the Aachener Aphasie Test (AAT) in different fields of spontaneous speech, with superimposable results at the follow-up. Albeit preliminary, these findings support the use of MRT in the rehabilitation after stroke. Specifically, MRT seems to benefit from its stronger structure than the available stimulation-facilitation procedures and allows a better quantification of the rehabilitation efficacy. PMID:26441615

  19. Following the Instructions! Effects of Gender Beliefs in Mental Rotation

    ERIC Educational Resources Information Center

    Moe, Angelica; Pazzaglia, Francesca

    2006-01-01

    Research has widely demonstrated male superiority in the Mental Rotation Test (MRT). Various explanations have been put forward to account for these differences. We considered gender beliefs and argued that women may fare less well than men partly because they are considered unable to perform this kind of task. Beliefs about spatial ability were…

  20. Are Males Always Better than Females in Mental Rotation? Exploring a Gender Belief Explanation

    ERIC Educational Resources Information Center

    Moe, Angelica

    2009-01-01

    Males outperform females in the Mental Rotation Test (MRT) for biological, strategic and cultural reasons. The present research tested a motivational explanation with the hypothesis that females could do better when induced to have positive beliefs and expectations. All-female and all-male samples were divided into six groups, each having listened…

  1. Aeromedical Lessons from the Space Shuttle Columbia Accident Investigation

    NASA Technical Reports Server (NTRS)

    Pool, Sam L.

    2005-01-01

    This paper presents the aeromedical lessons learned from the Space Shuttle Columbia Accident Investigation. The contents include: 1) Introduction and Mission Response Team (MRT); 2) Primary Disaster Field Office (DFO); 3) Mishap Investigation Team (MIT); 4) Kennedy Space Center (KSC) Mishap Response Plan; 5) Armed Forces Institute of Pathology (AFIP); and 6) STS-107 Crew Surgeon.

  2. Gender-Specific Effects of Artificially Induced Gender Beliefs in Mental Rotation

    ERIC Educational Resources Information Center

    Heil, Martin; Jansen, Petra; Quaiser-Pohl, Claudia; Neuburger, Sarah

    2012-01-01

    Men outperform women in the Mental Rotation Test (MRT) by about one standard deviation. The present study replicated a gender belief account [Moe, A., & Pazzaglia, F. (2006). Following the instructions! Effects of gender beliefs in mental rotation. Learning and Individual Differences, 16, 369-377.] for (part of) this effect. A sample of 300…

  3. Magnetic Resonance Thermometry at 7T for Real-Time Monitoring and Correction of Ultrasound Induced Mild Hyperthermia

    PubMed Central

    Fite, Brett Z.; Liu, Yu; Kruse, Dustin E.; Caskey, Charles F.; Walton, Jeffrey H.; Lai, Chun-Yen; Mahakian, Lisa M.; Larrat, Benoit; Dumont, Erik; Ferrara, Katherine W.

    2012-01-01

    While Magnetic Resonance Thermometry (MRT) has been extensively utilized for non-invasive temperature measurement, there is limited data on the use of high field (≥7T) scanners for this purpose. MR-guided Focused Ultrasound (MRgFUS) is a promising non-invasive method for localized hyperthermia and drug delivery. MRT based on the temperature sensitivity of the proton resonance frequency (PRF) has been implemented in both a tissue phantom and in vivo in a mouse Met-1 tumor model, using partial parallel imaging (PPI) to speed acquisition. An MRgFUS system capable of delivering a controlled 3D acoustic dose during real time MRT with proportional, integral, and derivative (PID) feedback control was developed and validated. Real-time MRT was validated in a tofu phantom with fluoroptic temperature measurements, and acoustic heating simulations were in good agreement with MR temperature maps. In an in vivo Met-1 mouse tumor, the real-time PID feedback control is capable of maintaining the desired temperature with high accuracy. We found that real time MR control of hyperthermia is feasible at high field, and k-space based PPI techniques may be implemented for increasing temporal resolution while maintaining temperature accuracy on the order of 1°C. PMID:22536396

  4. Rehabilitation of aphasia: application of melodic-rhythmic therapy to Italian language

    PubMed Central

    Cortese, Maria Daniela; Riganello, Francesco; Arcuri, Francesco; Pignataro, Luigina Maria; Buglione, Iolanda

    2015-01-01

    Aphasia is a complex disorder, frequent after stroke (with an incidence of 38%), with a detailed pathophysiological characterization. Effective approaches are crucial for devising an efficient rehabilitative strategy, in order to address the everyday life and professional disability. Several rehabilitative procedures are based on psycholinguistic, cognitive, psychosocial or pragmatic approaches, including amongst those with a neurobehavioral approach the Melodic Intonation Therapy (MIT). Van Eeckhout’s adaptation of MIT to French language (Melodic-Rhythmic Therapy: MRT) has implemented the training strategy by adding a rhythmic structure reproducing French prosody. The purpose of this study was to adapt MRT rehabilitation procedures to Italian language and to verify its efficacy in a group of six chronic patients (five males) with severe non-fluent aphasia and without specific aphasic treatments during the previous 9 months. The patients were treated 4 days a week for 16 weeks, with sessions of 30–40 min. They were assessed 6 months after the end of the treatment (follow-up). The patients showed a significant improvement at the Aachener Aphasie Test (AAT) in different fields of spontaneous speech, with superimposable results at the follow-up. Albeit preliminary, these findings support the use of MRT in the rehabilitation after stroke. Specifically, MRT seems to benefit from its stronger structure than the available stimulation-facilitation procedures and allows a better quantification of the rehabilitation efficacy. PMID:26441615

  5. Biocrust morphogroups provide an effective and rapid assessment tool for drylands

    PubMed Central

    Read, Cassia F; Duncan, David H; Vesk, Peter A; Elith, Jane; Wan, Shiqiang

    2014-01-01

    Biological soil crusts (biocrusts) occur across most of the world's drylands and are sensitive indicators of dryland degradation. Accounting for shifts in biocrust composition is important for quantifying integrity of arid and semi-arid ecosystems, but the best methods for assessing biocrusts are uncertain. We investigate the utility of surveying biocrust morphogroups, a reduced set of biotic classes, compared to species data, for detecting shifts in biocrust composition and making inference about dryland degradation. We used multivariate regression tree (MRT) analyses to model morphogroup abundance, species abundance and species occurrence data from two independent studies in semi-arid open woodlands of south-eastern Australia. We advanced the MRT method with a ‘best subsets’ model selection procedure, which improved model stability and prediction. Biocrust morphogroup composition responded strongly to surrogate variables of ecological degradation. Further, MRT models of morphogroup data had stronger explanatory power and predictive power than MRT models of species abundance or occurrence data. We also identified morphogroup indicators of degraded and less degraded sites in our study region. Synthesis and applications. Sustainable management of drylands requires methods to assess shifts in ecological integrity. We suggest that biocrust morphogroups are highly suitable for assessment of dryland integrity because they allow for non-expert, rapid survey and are informative about ecological function. Furthermore, morphogroups were more robust than biocrust species data, showed a strong response to ecological degradation and were less influenced by environmental variation, and models of morphogroup abundance were more predictive. PMID:25598550

  6. [Comparison of SCORE and Reynolds cardiovascular risk assessments in a cohort without cardiovascular disease].

    PubMed

    Móczár, Csaba

    2013-10-27

    Bevezetés: A cardiovascularis kockázat meghatározása segít a tünetmentes, de nagy kockázatú egyének kiszűrésében. Célkitűzés: A szerző tanulmányában az irányított betegellátási modellkísérlet keretében szervezett, cardiovascularis betegségtől mentes népesség szűrési adatai alapján a SCORE és a Reynolds kockázatbesorolási rendszer korrelációjának vizsgálatát tűzte ki célul. Módszer: Munkájában 4462 személy (1977 férfi, 2485 nő, átlagéletkor 47,44 év) adatait dolgozta fel. Az összehasonlítás alapját a SCORE rendszer kockázatkategóriái képezték. Eredmények: Alacsony kockázatstátus esetén szorosan korrelált a két rendszer (<2% alatti SCORE-kockázat esetén a Spearman rho = 1, p < 0,001). Közepes kockázat esetén a korreláció gyengébb (3–4% között rho = 0,59–0,49, p < 0,001, 10–14%-nál 0,42, nem szignifikáns), míg magas kockázatstátusnál ismét erősebb volt (>15%-nál rho = 0,8, p = 0,017). Életkori kategóriánként, nemenként vizsgálva: 40 év feletti nőknél volt a leggyengébb a két rendszer közti korreláció. A jelentősen eltérő Reynolds-score esetén a C-reaktív fehérje átlaga szignifikánsan nagyobb volt (4,1 vs. 5,67 mg/l, p < 0,001). Következtetések: Különösen a közepes SCORE kockázatstátusú, középkorú nőknél lehet hasznos a kockázatstátus pontosítása a C-reaktív fehérje felhasználásával, kétlépcsős kockázatbecslés bevezetésével. Orv. Hetil., 2013, 154, 1709–1712.

  7. Quantifizierung neurodegenerativer Veränderungen bei der Alzheimer Krankheit

    NASA Astrophysics Data System (ADS)

    Fritzsche, Klaus H.; Giesel, Frederik L.; Thomann, Philipp A.; Hahn, Horst K.; Essig, Marco; Meinzer, Hans-Peter

    Die objektive Bewertung neurodegenerativer Prozesse stellt für die Diagnose und Therapiebegutachtung neuropsychiatrischer Krankheiten eine wichtige Grundlage dar. Computerbasierte radiodiagnostische Verfahren können pathologische Veränderungen in verschiedenen Hirnarealen quantifizieren und hierbei die rein visuelle Beurteilung der Bilddaten ergänzen. Inhalt dieser Studie ist die Evaluation einer voll automatischen Methode zur voxelbasierten Messung atrophischer Veränderungen im Gehirn, wie sie bei der Alzheimer-Demenz (AD) oder der leichten kognitiven Störung (LKS) auftreten. Es wurde eine signifikante Korrelation mit den semiautomatisch extrahierten Volumina der Temporalhörner festgestellt. Die Präzision, Benutzerfreundlichkeit, Beobachterunabh ängigkeit sowie die kurze Rechenzeit des automatischen Verfahrens sind wichtige Voraussetzungen für den routinemäßigen klinischen Einsatz.

  8. Proton microbeam radiotherapy with scanned pencil-beams--Monte Carlo simulations.

    PubMed

    Kłodowska, M; Olko, P; Waligórski, M P R

    2015-09-01

    Irradiation, delivered by a synchrotron facility, using a set of highly collimated, narrow and parallel photon beams spaced by 1 mm or less, has been termed Microbeam Radiation Therapy (MRT). The tolerance of healthy tissue after MRT was found to be better than after standard broad X-ray beams, together with a more pronounced response of malignant tissue. The microbeam spacing and transverse peak-to-valley dose ratio (PVDR) are considered to be relevant biological MRT parameters. We investigated the MRT concept for proton microbeams, where we expected different depth-dose profiles and PVDR dependences, resulting in skin sparing and homogeneous dose distributions at larger beam depths, due to differences between interactions of proton and photon beams in tissue. Using the FLUKA Monte Carlo code we simulated PVDR distributions for differently spaced 0.1 mm (sigma) pencil-beams of entrance energies 60, 80, 100 and 120 MeV irradiating a cylindrical water phantom with and without a bone layer, representing human head. We calculated PVDR distributions and evaluated uniformity of target irradiation at distal beam ranges of 60-120 MeV microbeams. We also calculated PVDR distributions for a 60 MeV spread-out Bragg peak microbeam configuration. Application of optimised proton MRT in terms of spot size, pencil-beam distribution, entrance beam energy, multiport irradiation, combined with relevant radiobiological investigations, could pave the way for hypofractionation scenarios where tissue sparing at the entrance, better malignant tissue response and better dose conformity of target volume irradiation could be achieved, compared with present proton beam radiotherapy configurations.

  9. Low ambient temperature elevates plasma triiodothyronine concentrations while reducing digesta mean retention time and methane yield in sheep.

    PubMed

    Barnett, M C; McFarlane, J R; Hegarty, R S

    2015-06-01

    Ruminant methane yield (MY) is positively correlated with mean retention time (MRT) of digesta. The hormone triiodothyronine (T3 ), which is negatively correlated with ambient temperature, is known to influence MRT. It was hypothesised that exposing sheep to low ambient temperatures would increase plasma T3 concentration and decrease MRT of digesta within the rumen of sheep, resulting in a reduction of MY. To test this hypothesis, six Merino sheep were exposed to two different ambient temperatures (cold treatment, 9 ± 1 °C; warm control 26 ± 1 °C). The effects on MY, digesta MRT, plasma T3 concentration, CO2 production, DM intake, DM digestibility, change in body weight (BW), rumen volatile fatty acid (VFA) concentrations, estimated microbial protein output, protozoa abundance, wool growth, water intake, urine output and rectal temperature were studied. Cold treatment resulted in a reduction in MY (p < 0.01); digesta MRT in rumen (p < 0.01), hindgut (p = 0.01) and total digestive tract (p < 0.01); protozoa abundance (p < 0.05); and water intake (p < 0.001). Exposure to cold temperature increased plasma T3 concentration (p < 0.05), CO2 production (p = 0.01), total VFA concentrations (p = 0.03) and estimated microbial output from the rumen (p = 0.03). The rate of wool growth increased (p < 0.01) due to cold treatment, but DM intake, DM digestibility and BW change were not affected. The results suggest that exposure of sheep to cold ambient temperatures reduces digesta retention time in the gastrointestinal tract, leading to a reduction in enteric methane yield. Further research is warranted to determine whether T3 could be used as an indirect selection tool for genetic selection of low enteric methane-producing ruminants.

  10. Comparison of two methods for measuring γ-H2AX nuclear fluorescence as a marker of DNA damage in cultured human cells: applications for microbeam radiation therapy

    NASA Astrophysics Data System (ADS)

    Anderson, D.; Andrais, B.; Mirzayans, R.; Siegbahn, E. A.; Fallone, B. G.; Warkentin, B.

    2013-06-01

    Microbeam radiation therapy (MRT) delivers single fractions of very high doses of synchrotron x-rays using arrays of microbeams. In animal experiments, MRT has achieved higher tumour control and less normal tissue toxicity compared to single-fraction broad beam irradiations of much lower dose. The mechanism behind the normal tissue sparing of MRT has yet to be fully explained. An accurate method for evaluating DNA damage, such as the γ-H2AX immunofluorescence assay, will be important for understanding the role of cellular communication in the radiobiological response of normal and cancerous cell types to MRT. We compare two methods of quantifying γ-H2AX nuclear fluorescence for uniformly irradiated cell cultures: manual counting of γ-H2AX foci by eye, and an automated, MATLAB-based fluorescence intensity measurement. We also demonstrate the automated analysis of cell cultures irradiated with an array of microbeams. In addition to offering a relatively high dynamic range of γ-H2AX signal versus irradiation dose ( > 10 Gy), our automated method provides speed, robustness, and objectivity when examining a series of images. Our in-house analysis facilitates the automated extraction of the spatial distribution of the γ-H2AX intensity with respect to the microbeam array — for example, the intensities in the peak (high dose area) and valley (area between two microbeams) regions. The automated analysis is particularly beneficial when processing a large number of samples, as is needed to systematically study the relationship between the numerous dosimetric and geometric parameters involved with MRT (e.g., microbeam width, microbeam spacing, microbeam array dimensions, peak dose, valley dose, and geometric arrangement of multiple arrays) and the resulting DNA damage.

  11. Influence of ruminal methane on digesta retention and digestive physiology in non-lactating dairy cattle.

    PubMed

    Dittmann, Marie T; Hammond, Kirsty J; Kirton, Paul; Humphries, David J; Crompton, Les A; Ortmann, Sylvia; Misselbrook, Tom H; Südekum, Karl-Heinz; Schwarm, Angela; Kreuzer, Michael; Reynolds, Christopher K; Clauss, Marcus

    2016-09-01

    Enteric methane (CH4) production is a side-effect of herbivore digestion, but it is unknown whether CH4 itself influences digestive physiology. We investigated the effect of adding CH4 to, or reducing it in, the reticulorumen (RR) in a 4×4 Latin square experiment with rumen-fistulated, non-lactating cows, with four treatments: (i) control, (ii) insufflation of CH4 (iCH4), (iii) N via rumen fistula, (iv) reduction of CH4 via administration of bromochloromethane (BCM). DM intake (DMI), apparent total tract digestibility, digesta mean retention times (MRT), rumen motility and chewing activity, spot breath CH4 emission (CH4exhal, litre/kg DMI) as well as CH4 dissolved in rumen fluid (CH4RRf, µg/ml) were measured. Data were analysed using mixed models, including treatment (or, alternatively, CH4exhal or CH4RRf) and DMI relative to body mass0·85 (rDMI) as covariates. rDMI was the lowest on the BCM treatment. CH4exhal was highest for iCH4 and lowest for BCM treatments, whereas only BCM affected (reduced) CH4RRf. After adjusting for rDMI, CH4RRf had a negative association with MRT in the gastrointestinal tract but not in the RR, and negative associations with fibre digestibility and measures of rumination activity. Adjusting for rDMI, CH4exhal had additionally a negative association with particle MRT in the RR and a positive association with rumen motility. Thus, higher rumen levels of CH4 (CH4exhal or CH4RRf) were associated with shorter MRT and increased motility. These findings are tentatively interpreted as a feedback mechanism in the ruminant digestive tract that aims at mitigating CH4 losses by shortening MRT at higher CH4. PMID:27452637

  12. SNF5/INI1 Deficiency Redefines Chromatin Remodeling Complex Composition During Tumor Development

    PubMed Central

    Wei, Darmood; Goldfarb, Dennis; Song, Shujie; Cannon, Courtney; Yan, Feng; Sakellariou-Thompson, Donastas; Emanuele, Michael; Major, Michael B.; Weissman, Bernard E.; Kuwahara, Yasumichi

    2014-01-01

    Malignant Rhabdoid Tumors (MRTs), a pediatric cancer that most frequently appears in the kidney and brain, generally lack SNF5 (SMARCB1/INI1), a subunit of the SWI/SNF chromatin-remodeling complex. Recent studies have established that multiple SWI/SNF complexes exist due to the presence or absence of different complex members. Therefore, the effect of SNF5 loss upon SWI/SNF complex formation was investigated in human MRT cells. MRT cells and primary human tumors exhibited reduced levels of many complex proteins. Furthermore, re-expression of SNF5 increased SWI/SNF complex protein levels without concomitant increases in mRNA. Proteomic analysis, using mass spectrometry, of MRT cells before and after SNF5 re-expression indicated the recruitment of different components into the complex along with the expulsion of others. IP-Western blotting confirmed these results and demonstrated similar changes in other MRT cell lines. Finally, reduced expression of SNF5 in normal human fibroblasts led to altered levels of these same complex members. These data establish that SNF5 loss during MRT development alters the repertoire of available SWI/SNF complexes, generally disrupting those associated with cellular differentiation. These findings support a model where SNF5 inactivation blocks the conversion of growth promoting SWI/SNF complexes to differentiation inducing ones. Therefore, restoration of these complexes in tumors cells provides an attractive approach for the treatment of malignant rhabdoid tumors. Implications SNF5 loss dramatically alters SWI/SNF complex composition and prevents formation of complexes required for cellular differentiation. PMID:25009291

  13. Solute and particle retention in a small grazing antelope, the blackbuck (Antilope cervicapra).

    PubMed

    Hummel, Jürgen; Hammer, Sven; Hammer, Catrin; Ruf, Julia; Lechenne, Monique; Clauss, Marcus

    2015-04-01

    Digesta retention patterns have been suggested to play a major role in ruminant diversification. Two major digestion types have been proposed, termed 'cattle-type' and 'moose-type', that broadly correspond to the feeding categories of grazers and intermediate feeders on the one, and browsers on the other hand. We measured and calculated the mean retention time (MRT) of a solute and a particle (<2 mm) marker in the gastrointestinal tract (GIT) and the reticulorumen (RR) of a small grazer, the Indian blackbuck (Antilope cervicapra, n=5, body mass of 26±4 kg) and an intermediate feeder, the nilgai (Boselaphus tragocamelus, n=5, body mass of 168±21 kg). MRT(solute) and MRT(particle) were 29±4.1 h and 60±6.6 h in blackbuck and 28±2.5 h and 54±8.9 h in the nilgai for the GIT, and 14±1.7 h, 45±5.0 h, 19±2.0 h and 45±8.4 h for the RR, respectively. With a selectivity factor (SF, the ratio of MRT(particle) to MRT(solute)) in the RR of 3.2±0.28 for blackbuck and 2.3±0.36 for nilgai, both species are clearly in the category of 'cattle-type' ruminants. In particular, the high SFRR of blackbuck, in spite of its small body size, is remarkable, and leads to specific predictions on the RR anatomy of this species (such as a particularly large omasum), which can be tested in further studies. The adaptive value of a high SFRR is mainly considered as an increase in microbial productivity in the RR.

  14. Transit times of baseflow in New Zealand rivers

    NASA Astrophysics Data System (ADS)

    Morgenstern, Uwe; Stewart, Mike; Daughney, Chris; Townsend, Dougal

    2015-04-01

    Water quantity and quality responses of catchments to climate and land-use changes are difficult to understand and predict due to complexities of subsurface water flow paths and potentially large groundwater stores. It is difficult to relate the hydrologic responses of catchments to measurable catchment properties. Tritium is ideally suited to provide a measurable parameter of hydrologic response. Tritium, a component of meteoric water, decays with a half-life of 12.32 years after the water enters the groundwater system, and can therefore provide information on transit time of water through the groundwater system over the time range 0 to 200 years mean residence time (MRT). Transit time of the water discharge is one of the most crucial parameters for understanding the response of catchments. In recent years it has become possible to use tritium in a straightforward way for dating of stream and river water due to the decay of the bomb-tritium from atmospheric thermo-nuclear weapons testing, and to improved measurement accuracy for the extremely low natural tritium concentrations. Tritium dating of river water during baseflow conditions from over 120 sites throughout New Zealand show consistent patterns and a good correlation between geology and residence times of the water discharges. Basement rock catchments (greywacke, schist) have very young water of MRT less than 1year, sand-, mud-, limestone catchments have moderately old water of MRT 3-15 years, and porous ignimbrite catchments have very old water of MRT greater than 100 years. For example, the tritium data indicate MRT of 6 - 7 years in the Whanganui River, 3 - 3.5 years in the Rangitikei River, and 9 - 11 years in the large discharges from the Tertiary sediments in the Manawatu catchment. The discharges from the greywacke Ruahine and Tararua Ranges contain very young water with MRT of 0 - 2 years. Associated groundwater stores for the Rangitikei, Manawatu, and Whanganui Rivers are 1, 2, and 5 x 109 m3 of

  15. Assessing the Jarman-Bell Principle: Scaling of intake, digestibility, retention time and gut fill with body mass in mammalian herbivores.

    PubMed

    Müller, Dennis W H; Codron, Daryl; Meloro, Carlo; Munn, Adam; Schwarm, Angela; Hummel, Jürgen; Clauss, Marcus

    2013-01-01

    Differences in allometric scaling of physiological characters have the appeal to explain species diversification and niche differentiation along a body mass (BM) gradient - because they lead to different combinations of physiological properties, and thus may facilitate different adaptive strategies. An important argument in physiological ecology is built on the allometries of gut fill (assumed to scale to BM(1.0)) and energy requirements/intake (assumed to scale to BM(0.75)) in mammalian herbivores. From the difference in exponents, it has been postulated that the mean retention time (MRT) of digesta should scale to BM(1.0-0.75)=BM(0.25). This has been used to argue that larger animals have an advantage in digestive efficiency and hence can tolerate lower-quality diets. However, empirical data does not support the BM(0.25) scaling of MRT, and the deduction of MRT scaling implies, according to physical principles, no scaling of digestibility; basing assumptions on digestive efficiency on the thus-derived MRT scaling amounts to circular reasoning. An alternative explanation considers a higher scaling exponent for food intake than for metabolism, allowing larger animals to eat more of a lower quality food without having to increase digestive efficiency; to date, this concept has only been explored in ruminants. Here, using data for 77 species in which intake, digestibility and MRT were measured (allowing the calculation of the dry matter gut contents (DMC)), we show that the unexpected shallow scaling of MRT is common in herbivores and may result from deviations of other scaling exponents from expectations. Notably, DMC have a lower scaling exponent than 1.0, and the 95% confidence intervals of the scaling exponents for intake and DMC generally overlap. Differences in the scaling of wet gut contents and dry matter gut contents confirm a previous finding that the dry matter concentration of gut contents decreases with body mass, possibly compensating for the less

  16. Clinical variability of cyclosporine pharmacokinetics in adult and pediatric patients after renal, cardiac, hepatic, and bone-marrow transplants.

    PubMed

    Clardy, C W; Schroeder, T J; Myre, S A; Wadhwa, N K; Pesce, A J; First, M R; McEnery, P T; Balistreri, W F; Harris, R E; Melvin, D B

    1988-10-01

    The most important limitation associated with the clinical use of cyclosporine is the narrow therapeutic range between its efficacy and toxicity. Effective treatment is further complicated by significant variation in intrapatient and interpatient pharmacokinetics of the drug. We describe a practical approach to pharmacokinetic analysis that does not interfere with the cyclosporine dosage regimen or with clinical management of the patient. To optimize therapy, we individualized patient management by using noncompartmental pharmacokinetic analysis. Mean residence time (MRT) and volume of distribution at steady-state were calculated from data on concentration vs time after dose. We applied this approach to 24 kidney, 12 heart, 8 bone-marrow, 7 liver, and 5 pancreas transplants. Individualized requirements for cyclosporine dose and dosage interval can be predicted from these parameters. MRT is the most useful pharmacokinetic parameter, because it allows prediction of the optimal dosage interval. PMID:3048779

  17. Mitochondrial replacement therapy in reproductive medicine.

    PubMed

    Wolf, Don P; Mitalipov, Nargiz; Mitalipov, Shoukhrat

    2015-02-01

    Mitochondrial dysfunction is implicated in disease and age-related infertility. Mitochondrial replacement therapies (MRT) in oocytes or zygotes, such as pronuclear (PNT), spindle (ST), or polar body (PBT) transfer, could prevent second-generation transmission of mitochondrial DNA (mtDNA) defects. PNT, associated with high levels of mtDNA carryover in mice but low levels in human embryos, carries ethical issues secondary to donor embryo destruction. ST, developed in primates, supports normal development to adults and low mtDNA carryover. PBT in mice, coupled with PN or ST, may increase the yield of reconstructed embryos with low mtDNA carryover. MRT also offers replacement of the deficient cytoplasm in oocytes from older patients, with the expectation of high pregnancy rates following in vitro fertilization. PMID:25573721

  18. Mechanism-based model of a mass rapid transit system: A perspective

    NASA Astrophysics Data System (ADS)

    Legara, Erika Fille; Khoon, Lee Kee; Guang, Hung Gih; Monterola, Christopher

    2015-01-01

    In this paper, we discuss our findings on the spatiotemporal dynamics within the mass rapid transit (MRT) system of Singapore. We show that the trip distribution of Origin-Destination (OD) station pairs follows a power-law, implying the existence of critical OD pairs. We then present and discuss the empirically validated agent-based model (ABM) we have developed. The model allows recreation of the observed statistics and the setting up of various scenarios and their effects on the system, such as increasing the commuter population and the propagation of travel delays within the transportation network. The proposed model further enables identification of bottlenecks that can cause the MRT to break down, and consequently provide foresight on how such disruptions can possibly be managed. This can potentially provide a versatile approach for transport planners and government regulators to make quantifiable policies that optimally balance cost and convenience as a function of the number of the commuting public.

  19. An accelerated photo-magnetic imaging reconstruction algorithm based on an analytical forward solution and a fast Jacobian assembly method

    NASA Astrophysics Data System (ADS)

    Nouizi, F.; Erkol, H.; Luk, A.; Marks, M.; Unlu, M. B.; Gulsen, G.

    2016-10-01

    We previously introduced photo-magnetic imaging (PMI), an imaging technique that illuminates the medium under investigation with near-infrared light and measures the induced temperature increase using magnetic resonance thermometry (MRT). Using a multiphysics solver combining photon migration and heat diffusion, PMI models the spatiotemporal distribution of temperature variation and recovers high resolution optical absorption images using these temperature maps. In this paper, we present a new fast non-iterative reconstruction algorithm for PMI. This new algorithm uses analytic methods during the resolution of the forward problem and the assembly of the sensitivity matrix. We validate our new analytic-based algorithm with the first generation finite element method (FEM) based reconstruction algorithm previously developed by our team. The validation is performed using, first synthetic data and afterwards, real MRT measured temperature maps. Our new method accelerates the reconstruction process 30-fold when compared to a single iteration of the FEM-based algorithm.

  20. Monte Carlo-based treatment planning system calculation engine for microbeam radiation therapy

    SciTech Connect

    Martinez-Rovira, I.; Sempau, J.; Prezado, Y.

    2012-05-15

    Purpose: Microbeam radiation therapy (MRT) is a synchrotron radiotherapy technique that explores the limits of the dose-volume effect. Preclinical studies have shown that MRT irradiations (arrays of 25-75-{mu}m-wide microbeams spaced by 200-400 {mu}m) are able to eradicate highly aggressive animal tumor models while healthy tissue is preserved. These promising results have provided the basis for the forthcoming clinical trials at the ID17 Biomedical Beamline of the European Synchrotron Radiation Facility (ESRF). The first step includes irradiation of pets (cats and dogs) as a milestone before treatment of human patients. Within this context, accurate dose calculations are required. The distinct features of both beam generation and irradiation geometry in MRT with respect to conventional techniques require the development of a specific MRT treatment planning system (TPS). In particular, a Monte Carlo (MC)-based calculation engine for the MRT TPS has been developed in this work. Experimental verification in heterogeneous phantoms and optimization of the computation time have also been performed. Methods: The penelope/penEasy MC code was used to compute dose distributions from a realistic beam source model. Experimental verification was carried out by means of radiochromic films placed within heterogeneous slab-phantoms. Once validation was completed, dose computations in a virtual model of a patient, reconstructed from computed tomography (CT) images, were performed. To this end, decoupling of the CT image voxel grid (a few cubic millimeter volume) to the dose bin grid, which has micrometer dimensions in the transversal direction of the microbeams, was performed. Optimization of the simulation parameters, the use of variance-reduction (VR) techniques, and other methods, such as the parallelization of the simulations, were applied in order to speed up the dose computation. Results: Good agreement between MC simulations and experimental results was achieved, even at

  1. SPECT measurements with /sup 99m/Tc-HM-PAO in focal epilepsy

    SciTech Connect

    Ryding, E.; Rosen, I.; Elmqvist, D.; Ingvar, D.H.

    1988-12-01

    The ability of SPECT measurements with (/sup 99m/Tc)-HM-PAO (Ceretec) to find the location of the epileptic focus was studied in patients under consideration for neurosurgical treatment for therapy-resistant focal epilepsy. The location of low (/sup 99m/Tc)-HM-PAO uptake regions found at interictal measurements, and of high (/sup 99m/Tc)-HM-PAO uptake regions found at ictal measurements, was compared to the findings of extensive ictal and interictal EEG examinations, and to the results of CT and MRT. While EEG revealed focal epileptic activity in all of the 14 patients, SPECT showed regional abnormalities in 13 (93%). CT and MRT showed abnormal findings in 30%.

  2. Monitoring of Brucella reactor does following milk examination using different techniques.

    PubMed

    el-Razik, K A Abd; Ghazi, Y A; Salama, E M

    2007-01-15

    Milk samples from 129 does were collected and monitored for Brucella antibodies using immunological tests such as Milk Ring Test (MRT), Whey Agglutination Test (WAT), Whey Antiglobulin Coombs Test (WCT) and milk ELISA (m ELISA) using Brucella Periplasmic protein antigen. Results obtained from these tests were compared to PCR and bacterial isolation. The highest incidence of positive reactors was given by Whey Antiglobulin and Whey Agglutination Test (9.3%) while the lowest incidence was given by bacterial isolation (Br. melitensis biovars 3, 3.8%). PCR showed the highest agreement with the bacterial isolation, while WAT and WCT showed the lowest one. PCR showed a high sensitivity of 1 x 10 B. melitensis CFU mL(-1) of milk. The results of mELISA here suggests its efficiency to be used as a screening test and/or confirmatory test, while the modified MRT still need more investigations to diagnosis caprine brucellosis. PMID:19070022

  3. Multiple-relaxation-time lattice Boltzmann method for immiscible fluids at high Reynolds numbers.

    PubMed

    Fakhari, Abbas; Lee, Taehun

    2013-02-01

    The lattice Boltzmann method for immiscible multiphase flows with large density ratio is extended to high Reynolds number flows using a multiple-relaxation-time (MRT) collision operator, and its stability and accuracy are assessed by simulating the Kelvin-Helmholtz instability. The MRT model is successful at damping high-frequency oscillations in the kinetic energy emerging from traveling waves generated by the inclusion of curvature. Numerical results are shown to be in good agreement with prior studies using adaptive mesh refinement techniques applied to the Navier-Stokes equations. Effects of viscosity and surface tension, as well as density ratio, are investigated in terms of the Reynolds and Weber numbers. It is shown that increasing the Reynolds number results in a more chaotic interface evolution and eventually shattering of the interface, while surface tension is shown to have a stabilizing effect.

  4. Mitochondrial Replacement Therapy in Reproductive Medicine

    PubMed Central

    Wolf, Don P.; Mitalipov, Nargiz; Mitalipov, Shoukhrat

    2015-01-01

    Mitochondrial dysfunction is implicated in disease and in age-related infertility. Mitochondrial replacement therapies (MRT) in oocytes or zygotes such as pronuclear (PNT), spindle (ST) or polar body (PBT) transfer could prevent second generation transmission of mitochondrial DNA (mtDNA) defects. PNT, associated with high levels of mtDNA carryover in mice but low levels in human embryos, carries ethical issues secondary to donor embryo destruction. ST, developed in primates, supports normal development to adults and low mtDNA carryover. PBT in mice, coupled with PN or ST, may increase the yield of reconstructed embryos with low mtDNA carryover. MRT also offers replacement of the deficient cytoplasm in oocytes from older patients, with the expectation of high pregnancy rates following in vitro fertilization. PMID:25573721

  5. The effect of gender and age differences on media selection in small and medium tourism enterprises.

    PubMed

    Dehkordi, Majid A; Zarei, Behrouz; Dehkordi, Shabnam A

    2008-12-01

    The purpose of this study is to examine the impact that gender and age differences have on the communication media selection within the context of small and medium tourism enterprises (SMEs). Media Richness Theory (MRT) was used to assess media preferences in the firms. Using a mail questionnaire, data from 78 firms were collected on seven popular media in use. Historical data of the firms, media characteristics, and other firm-specific factors were included in the analysis. The results indicated that there are substantial gender and age differences in term of communication media selection. This is consistent with MRT and highlights the importance of choosing the appropriate media in SMEs, according with the employee's behaviors, in order to achieve better outcomes and to smooth the path towards good performance in the future.

  6. Implicit versus explicit momentum relaxation time solution for semiconductor nanowires

    SciTech Connect

    Marin, E. G. Ruiz, F. G. Godoy, A. Tienda-Luna, I. M.; Gámiz, F.

    2015-07-14

    We discuss the necessity of the exact implicit Momentum Relaxation Time (MRT) solution of the Boltzmann transport equation in order to achieve reliable carrier mobility results in semiconductor nanowires. Firstly, the implicit solution for a 1D electron gas with a isotropic bandstructure is presented resulting in the formulation of a simple matrix system. Using this solution as a reference, the explicit approach is demonstrated to be inaccurate for the calculation of inelastic anisotropic mechanisms such as polar optical phonons, characteristic of III-V materials. Its validity for elastic and isotropic mechanisms is also evaluated. Finally, the implications of the MRT explicit approach inaccuracies on the total mobility of Si and III-V NWs are studied.

  7. Mitigation of Electrothermal Instabilities with Thick Insulating Coatings

    NASA Astrophysics Data System (ADS)

    Peterson, Kyle; Awe, Thomas; Yu, Edmund; Sinars, Daniel; Cuneo, Michael

    2013-10-01

    We will show results of recent experiments on Sandia's Z facility that demonstrate a dramatic reduction in instability growth when thick insulating coatings are used to mitigate electrothermal instability growth in magnetically driven imploding liners. These results also provide further evidence that the inherent surface roughness as a result of target fabrication is not the dominant seed for the growth of Magneto-Rayleigh-Taylor (MRT) instabilities in liners with carefully machined smooth surfaces (~100 nm surface RMS or better), but rather electrothermal instabilities that form early in the electrical current pulse as Joule heating melts and vaporizes the liner surface. More importantly, these results suggest a mechanism for possibly reducing the integral MRT instability growth substantially in magnetically driven inertial confinement fusion concepts such as MagLIF. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  8. Does field independence predict visuo-spatial abilities underpinning human navigation? Behavioural evidence.

    PubMed

    Boccia, Maddalena; Piccardi, Laura; Di Marco, Mariangela; Pizzamiglio, Luigi; Guariglia, Cecilia

    2016-10-01

    Field independence (FI) has been defined as the extent to which the individual perceives part of a field as discrete from the surrounding field, rather than embedded in the field. It has been proposed to represent a relatively stable pattern in individuals' predisposition towards information processing. In the present study, we assessed the effect of FI on skills underpinning human navigation. Fifty Healthy individuals took part in this study. FI has been assessed by using the group embedded figures test (GEFT). Participants were also asked to perform several visuo-spatial orientation tasks, including the perspective taking/spatial orientation test (PTSOT), the mental rotation task (MRT) and the vividness task, as well as the Santa Barbara Sense of Direction Scale, a self-reported questionnaire, which has been found to predict environmental spatial orientation ability. We found that performances on the GEFT significantly predicted performances on the PTSOT and the MRT. This result supports the idea that FI predicts human navigation.

  9. Compact cryogenic system with mechanical cryocoolers for antihydrogen synthesis.

    PubMed

    Shibata, M; Mohri, A; Kanai, Y; Enomoto, Y; Yamazaki, Y

    2008-01-01

    We have developed a compact cryogenic system which cools a vacuum chamber housing multi-ring trap electrodes (MRTs) of an antihydrogen synthesis trap using mechanical cryocoolers to achieve background pressure less than 10(-12) Torr. The vacuum chamber and the cryocoolers are thermally connected by copper strips of 99.9999% in purity. All components are installed within a diametric gap between the MRT of phi108 mm and a magnet bore of phi160 mm. An adjusting mechanism is prepared to align the MRT axis to the magnet axis. The vacuum chamber was successfully cooled down to 4.0 K after 14 h of cooling with heat load of 0.8 W.

  10. Accuracy and grid convergence of wall shear stress measured by lattice Boltzmann method

    NASA Astrophysics Data System (ADS)

    Kang, Xiuying; Dun, Zhiya

    2014-04-01

    Based on a two-dimensional Poiseuille and Wormersley flow, accuracy and grid convergence of velocity, shear stress and wall shear stress (WSS) measurements were investigated using the single-relaxation-time (SRT) and multiple-relaxation-time (MRT) lattice Boltzmann models under various open and wall boundary conditions. The results showed that grid convergence of shear stress and WSS are not consistent with that of velocity when flow channels are not aligned to the grids, and strongly rely on the used wall boundary conditions. And the MRT model is slightly superior to the SRT when simulating the complicated border flow. Moreover the WSS should be approximately calculated on the fluid nodes closest to walls under the curved boundary (CB) condition but not for the bounce-back (BB) boundary scheme. As applications, distributions of WSS in a wavy-walled channel and distensible carotid artery were simulated which would much more depend on local roughness of vessel intima than channel diameters.

  11. Attractiveness in African American and Caucasian women: is beauty in the eyes of the observer?

    PubMed

    Davis, Dawnavan S; Sbrocco, Tracy; Odoms-Young, Angela; Smith, Dionne M

    2010-01-01

    Traditional body image studies have been constrained by focusing on body thinness as the sole component of attractiveness. Evidence suggests that African American women may hold a multifactorial view of attractiveness that extends beyond size to include factors such as dress attire and race. The current study employed a culturally sensitive silhouette Model Rating Task (MRT) to examine the effects of attire, body size, and race on attractiveness. Unexpectedly, minimal differences on attractiveness ratings emerged by attire, body size, or model race between African American and Caucasian women. Overall, participants preferred the dressed, underweight, and African American models. Factors such as exposure to diverse groups and changes in African American culture may explain the present findings. Future studies to delineate the components of attractiveness for African American and Caucasian women using the MRT are needed to broaden our understanding and conceptualization of attractiveness across racial groups.

  12. Attractiveness in African American and Caucasian Women: Is Beauty in the Eyes of the Observer?

    PubMed Central

    Davis, Dawnavan S.; Sbrocco, Tracy; Odoms-Young, Angela; Smith, Dionne M.

    2010-01-01

    Traditional body image studies have been constrained by focusing on body thinness as the sole component of attractiveness. Evidence suggests that African American women may hold a multifactorial view of attractiveness that extends beyond size to include factors such as dress attire and race. The current study employed a culturally sensitive silhouette Model Rating Task (MRT) to examine the effects of attire, body size, and race on attractiveness. Unexpectedly, minimal differences on attractiveness ratings emerged by attire, body size, or model race between African American and Caucasian women. Overall, participants preferred the dressed, underweight, and African American models. Factors such as exposure to diverse groups and changes in African American culture may explain the present findings. Future studies to delineate the components of attractiveness for African American and Caucasian women using the MRT are needed to broaden our understanding and conceptualization of attractiveness across racial groups. PMID:19962117

  13. Magneto-Rayleigh-Taylor, Sausage And Kink Mode In Cylindrical Liners

    NASA Astrophysics Data System (ADS)

    Lau, Y. Y.; Zhang, Peng; Weis, Matthew; Gilgenbach, Ronald; Hess, Mark; Peterson, Kyle

    2014-10-01

    This paper analyzes the coupling of magneto-Rayleigh-Taylor (MRT), sausage (azimuthal mode number m = 0) and kink mode (m = 1) in an imploding cylindrical liner, using ideal MHD. A uniform axial magnetic field of arbitrary value is included in each region: liner, its interior, and its exterior. The dispersion relation, the feedthrough factor, and the temporal evolution of perturbations were solved exactly, for arbitrary values of g (= gravity), k (= axial wavenumber), m, aspect ratio, and equilibrium quantities in each region. For small k, a positive g (inward radial acceleration in the lab frame) tends to stabilize the sausage mode, but destabilize the kink mode. For large k, a positive g destabilizes both the kink and sausage mode. This analysis might shed lights into some puzzling features in Harris' classic paper, and in the recent cylindrical liner experiments on MRT. M. R. Weis was supported by the Sandia National Laboratories.

  14. 2D HYDRA Calculations of Magneto-Rayleigh-Taylor Growth and Feedthrough in Cylindrical Liners

    NASA Astrophysics Data System (ADS)

    Weis, Matthew; Zhang, Peng; Lau, Y. Y.; Gilgenbach, Ronald; Peterson, Kyle; Hess, Mark

    2014-10-01

    Cylindrical liner implosions are susceptible to the magneto-Rayleigh-Taylor instability (MRT), along with the azimuthal current-carrying modes (sausage, kink, etc). ``Feedthrough'' of these instabilities has a strong influence on the integrity of the liner/fuel interface in the magnetized liner inertial fusion concept (MagLIF). The linearized ideal MHD equations can be solved to quantify these effects, including the presence of an effective gravity and an axial magnetic field. We investigate the potential of this field to mitigate feedthrough, due to MRT growth from various initial surface finishes (seeded, rough), throughout the implosion using our analytic results and the LLNL code, HYDRA. We will present both low and high convergence cases. Lastly, we illustrate the effect shock compression can have on feedthrough in seeded liners for various fill gases (cold and pre-heated) and magnetic field configurations. M. R. Weis was supported by the Sandia National Laboratories.

  15. Radiotracer investigation in an industrial-scale oxidizer.

    PubMed

    Pant, H J; Sharma, V K

    2015-05-01

    A radiotracer investigation was carried out in an industrial-scale oxidizer. The main objectives of the investigation were to measure residence time distribution (RTD) of organic process fluid, determine the mean residence time (MRT) and investigate the degree of axial mixing. Bromine-82 as p-dibromo biphenyl was used as a radiotracer for measuring RTD of the organic process fluid. The MRT of the fluid in the oxidizer was determined to be 390min. An ideal stirred tank model with a plug flow reactor in recirculation stream was used to simulate the measured RTD data and was found suitable for describing flow in the system. Based on the model simulation the mean residence times in oxidizer and recycle stream were estimated. The results of the investigation showed that the oxidizer behaved as a well-mixed reactor whereas the recycle stream behaved as a plug flow reactor. PMID:25766114

  16. Optimization of Integrated Impeller Mixer via Radiotracer Experiments

    PubMed Central

    Othman, N.; Kamarudin, S. K.; Takriff, M. S.; Rosli, M. I.; Engku Chik, E. M. F.; Adnan, M. A. K.

    2014-01-01

    Radiotracer experiments are carried out in order to determine the mean residence time (MRT) as well as percentage of dead zone, Vdead (%), in an integrated mixer consisting of Rushton and pitched blade turbine (PBT). Conventionally, optimization was performed by varying one parameter and others were held constant (OFAT) which lead to enormous number of experiments. Thus, in this study, a 4-factor 3-level Taguchi L9 orthogonal array was introduced to obtain an accurate optimization of mixing efficiency with minimal number of experiments. This paper describes the optimal conditions of four process parameters, namely, impeller speed, impeller clearance, type of impeller, and sampling time, in obtaining MRT and Vdead (%) using radiotracer experiments. The optimum conditions for the experiments were 100 rpm impeller speed, 50 mm impeller clearance, Type A mixer, and 900 s sampling time to reach optimization. PMID:24741344

  17. Fractionating soils so that others do not have to: radiocarbon informs choice of method for scale, ecosystem, or process

    NASA Astrophysics Data System (ADS)

    Crow, S. E.

    2011-12-01

    Physical separation of soil into various fractions has long been used to address questions concerning mechanisms of soil organic matter stabilization, processes contributing to soil carbon (C) accumulation, and the effects of land use, climate change, and management practice on soil quality and carbon sequestration. However, no published method works well for every soil, ecosystem, or research question. Often a chosen method does not effectively separate soil into C pools that differ in mean residence time (MRT) and sensitivity to change, which can complicate the interpretation of results. Soil C is stabilized by a variety of mechanisms and radiocarbon-based estimates of MRT can reveal the integrated effects of these mechanisms on bulk soil C storage; radiocarbon-based estimates of MRT on isolated soil fractions separated by a carefully chosen method can reveal internal C dynamics invisible to the bulk soil methods. A variety of soils collected around Hawaii (Mollisol, Oxisol, Andisol) were fractionated by several common methods and the radiocarbon-based MRT was estimated for comparison among fractions, soils, and methods. In some cases, depending on the research question of interest, aspects of different methods could be combined to reveal changes in soil C pools on both short and long time frames. For example, for a cultivated, mixed-mineralogy Mollisol, a method that combined a density separation at 1.8 g mL-1 for free light fraction, then calibrated sonication to disrupt aggregates for an occluded fraction, then further sequential fractionation at 2.0 g -1could produce soil C pools with turnover of 3.5 yr (free light fraction), 10 yr (occluded light fraction), 714 yr (1.8-2.0 fraction), and 2090 yr (<2.0 fraction). This method may be ideal for tracking short-term (1-10 year) changes in soil structure due to sustainable agriculture or management practices. For an Andisol, land conversion from old-growth native forest to 80 yr of pasture increased bulk soil C

  18. Pharmacokinetics of tilmicosin in equine tissues and plasma.

    PubMed

    Clark, C; Dowling, P M; Ross, S; Woodbury, M; Boison, J O

    2008-02-01

    The macrolide antibiotic tilmicosin has potential for treating bacterial respiratory tract infections in horses. A pharmacokinetic study evaluated the disposition of tilmicosin in the horse after oral (4 mg/kg) or subcutaneous (s.c.) (10 mg/kg) administration. Tilmicosin was not detected in equine plasma or tissues after oral administration at this dose. With s.c. injection, tilmicosin concentrations reached a maximum concentration of approximately 200 ng/mL in the plasma of the horses. Tilmicosin concentrations in plasma persisted with a mean residence time (MRT) of 19 h. Maximum tissue residue concentrations (C(max)) of tilmicosin measured in equine lung, kidney, liver and muscle tissues after s.c. administration were 2784, 4877, 1398, and 881 ng/g, respectively. The MRT of tilmicosin in these tissues was approximately 27 h. Subcutaneous administration of tilmicosin resulted in severe reactions at the injection sites.

  19. Testosterone levels and mental rotation performance in Chinese men.

    PubMed

    Yang, Chi-Fu Jeffrey; Hooven, Carole K; Boynes, Matthew; Gray, Peter B; Pope, Harrison G

    2007-03-01

    Males achieve markedly higher scores than females on mental rotation tests (MRTs). Therefore, it might be hypothesized that, within groups of males, testosterone levels modulate MRT performance. However, studies of this relationship have yielded inconsistent results. Notably, a recent study of 28 American men, using the computerized Shepard and Metzler MRT (SM), found significant associations between salivary testosterone levels and the intercepts of the functions relating response time and error rate to the angular disparity between comparison objects. Conversely, a study of 35 British men, using the same methodology, found no such associations. We attempted a cross-cultural replication of these studies, in which we obtained salivary testosterone levels, together with performance measures on the SM, from 92 heterosexual right-handed men, aged 21-38, in Beijing, China. We hypothesized that Chinese men might perform more slowly and carefully than Western men on this test (which imposes no time limitations), but that associations of testosterone levels with performance, if real, should nevertheless be detectable across cultures. We found that the Chinese men indeed displayed significantly longer response times than the American men, although the Chinese men were equally accurate. Interestingly, testosterone was significantly associated with the slope of the response time function in Chinese men, whereas the earlier American study had found that testosterone was associated with the intercept, but not the slope, of this function. These observations suggest that differing cultural values regarding speed and accuracy may influence MRT performance--and that these values must be considered in future studies of testosterone and MRT measures.

  20. In vivo efficacy of the histone deacetylase inhibitor suberoylanilide hydroxamic acid in combination with radiotherapy in a malignant rhabdoid tumor mouse model

    PubMed Central

    2012-01-01

    Purpose Histone deacetylase inhibitors are promising new substances in cancer therapy and have also been shown to sensitize different tumor cells to irradiation (XRT). We explored the effect as well as the radiosensitizing properties of suberoylanilide hydroxamic acid (SAHA) in vivo in a malignant rhabdoid tumor (MRT) mouse model. Methods and material Potential radiosensitization by SAHA was assessed in MRT xenografts by analysis of tumor growth delay, necrosis (HE), apoptosis (TUNEL), proliferation (ki-67) and γH2AX expression as well as dynamic 18F-Fluorodeoxyglucose Positron Emission Tomography (18F-FDG -PET) after treatment with either SAHA alone, single-dose (10 Gy) or fractionated XRT (3 × 3Gy) solely as well as in combination with SAHA compared to controls. Results SAHA only had no significant effect on tumor growth. Combination of SAHA for 8 days with single-dose XRT resulted in a higher number of complete remissions, but failed to prove a significant growth delay compared to XRT only. In contrast fractionated XRT plus SAHA for 3 weeks did induce significant tumor growth delay in MRT-xenografts. The histological examination showed a significant effect of XRT in tumor necrosis, expression of Ki-67, γH2AX and apoptosis. SAHA only had no significant effect in the histological examination. Comparison of xenografts treated with XRT and XRT plus SAHA revealed a significantly increased γH2AX expression and apoptosis induction in the mice tumors after combination treatment with single-dose as well as fractionated XRT. The combination of SAHA with XRT showed a tendency to increased necrosis and decrease of proliferation compared to XRT only, which, however, was not significant. The 18F-FDG-PET results showed no significant differences in the standard uptake value or glucose transport kinetics after either treatment. Conclusion SAHA did not have a significant effect alone, but proved to enhance the effect of XRT in our MRT in vivo model. PMID:22458853

  1. Methodology for Validating Building Energy Analysis Simulations

    SciTech Connect

    Judkoff, R.; Wortman, D.; O'Doherty, B.; Burch, J.

    2008-04-01

    The objective of this report was to develop a validation methodology for building energy analysis simulations, collect high-quality, unambiguous empirical data for validation, and apply the validation methodology to the DOE-2.1, BLAST-2MRT, BLAST-3.0, DEROB-3, DEROB-4, and SUNCAT 2.4 computer programs. This report covers background information, literature survey, validation methodology, comparative studies, analytical verification, empirical validation, comparative evaluation of codes, and conclusions.

  2. Detecting the impact of bank and channel modification on invertebrate communities in Mediterranean temporary streams (Sardinia, SW Italy).

    PubMed

    Buffagni, Andrea; Tenchini, Roberta; Cazzola, Marcello; Erba, Stefania; Balestrini, Raffaella; Belfiore, Carlo; Pagnotta, Romano

    2016-09-15

    We hypothesized that reach-scale, bank and channel modification would impact benthic communities in temporary rivers of Sardinia, when pollution and water abstraction are not relevant. A range of variables were considered, which include both artificial structures/alterations and natural features observed in a stream reach. Multivariate regression trees (MRT) were used to assess the effects of the explanatory variables on invertebrate assemblages and five groups, characterized by different habitat modification and/or features, were recognized. Four node variables determined the splits in the MRT analysis: channel reinforcement, tree-related bank and channel habitats, channel modification and bank modification. Continuity of trees in the river corridor diverged among MRT groups and significant differences among groups include presence of alders, extent of channel shading and substrate diversity. Also, the percentage of in-stream organic substrates, in particular CPOM/Xylal, showed highly significant differences among groups. For practical applications, thresholds for the extent of channel reinforcement (40%) and modification (10%) and for bank alteration (≈30%) were provided, that can be used to guide the implementation of restoration measures. In moderately altered river reaches, a significant extent of tree-related habitats (≈5%) can noticeably mitigate the effects of morphological alteration on aquatic invertebrates. The outcomes highlight the importance of riparian zone management as an opportune, achievable prospect in the restoration of Mediterranean temporary streams. The impact of bank and channel modification on ecological status (sensu WFD) was investigated and the tested benthic metrics, especially those based on abundance data, showed legible differences among MRT groups. Finally, bank and channel modification appears to be a potential threat for the conservation of a few Sardo-Corsican endemic species. The introduction of management criteria that

  3. Mixing effects on nitrogen and oxygen concentrations and the relationship to mean residence time in a hyporheic zone of a riffle-pool sequence

    USGS Publications Warehouse

    Naranjo, Ramon C.; Niswonger, Richard G.; Clinton Davis,

    2015-01-01

    Flow paths and residence times in the hyporheic zone are known to influence biogeochemical processes such as nitrification and denitrification. The exchange across the sediment-water interface may involve mixing of surface water and groundwater through complex hyporheic flow paths that contribute to highly variable biogeochemically active zones. Despite the recognition of these patterns in the literature, conceptualization and analysis of flow paths and nitrogen transformations beneath riffle-pool sequences often neglect to consider bed form driven exchange along the entire reach. In this study, the spatial and temporal distribution of dissolved oxygen (DO), nitrate (NO3-) and ammonium (NH4+) were monitored in the hyporheic zone beneath a riffle-pool sequence on a losing section of the Truckee River, NV. Spatially-varying hyporheic exchange and the occurrence of multi-scale hyporheic mixing cells are shown to influence concentrations of DO and NO3- and the mean residence time (MRT) of riffle and pool areas. Distinct patterns observed in piezometers are shown to be influenced by the first large flow event following a steady 8 month period of low flow conditions. Increases in surface water discharge resulted in reversed hydraulic gradients and production of nitrate through nitrification at small vertical spatial scales (0.10 to 0.25 m) beneath the sediment-water interface. In areas with high downward flow rates and low MRT, denitrification may be limited. The use of a longitudinal two-dimensional flow model helped identify important mechanisms such as multi-scale hyporheic mixing cells and spatially varying MRT, an important driver for nitrogen transformation in the riverbed. Our observations of DO and NO3- concentrations and model simulations highlight the role of multi-scale hyporheic mixing cells on MRT and nitrogen transformations in the hyporheic zone of riffle-pool sequences. This article is protected by copyright. All rights reserved.

  4. Benchmarking and validation of a Geant4-SHADOW Monte Carlo simulation for dose calculations in microbeam radiation therapy.

    PubMed

    Cornelius, Iwan; Guatelli, Susanna; Fournier, Pauline; Crosbie, Jeffrey C; Sanchez Del Rio, Manuel; Bräuer-Krisch, Elke; Rosenfeld, Anatoly; Lerch, Michael

    2014-05-01

    Microbeam radiation therapy (MRT) is a synchrotron-based radiotherapy modality that uses high-intensity beams of spatially fractionated radiation to treat tumours. The rapid evolution of MRT towards clinical trials demands accurate treatment planning systems (TPS), as well as independent tools for the verification of TPS calculated dose distributions in order to ensure patient safety and treatment efficacy. Monte Carlo computer simulation represents the most accurate method of dose calculation in patient geometries and is best suited for the purpose of TPS verification. A Monte Carlo model of the ID17 biomedical beamline at the European Synchrotron Radiation Facility has been developed, including recent modifications, using the Geant4 Monte Carlo toolkit interfaced with the SHADOW X-ray optics and ray-tracing libraries. The code was benchmarked by simulating dose profiles in water-equivalent phantoms subject to irradiation by broad-beam (without spatial fractionation) and microbeam (with spatial fractionation) fields, and comparing against those calculated with a previous model of the beamline developed using the PENELOPE code. Validation against additional experimental dose profiles in water-equivalent phantoms subject to broad-beam irradiation was also performed. Good agreement between codes was observed, with the exception of out-of-field doses and toward the field edge for larger field sizes. Microbeam results showed good agreement between both codes and experimental results within uncertainties. Results of the experimental validation showed agreement for different beamline configurations. The asymmetry in the out-of-field dose profiles due to polarization effects was also investigated, yielding important information for the treatment planning process in MRT. This work represents an important step in the development of a Monte Carlo-based independent verification tool for treatment planning in MRT.

  5. Proton Resonance Frequency Chemical Shift Thermometry: Experimental Design and Validation Towards High-Resolution Non-Invasive Temperature Monitoring, and in vivo Experience in a Non-human Primate Model of Acute Ischemic Stroke

    PubMed Central

    Mao, Hui; Howell, Leonard; Zhang, Xiaodong; Pate, K S; Magrath, P R; Tong, Frank; Wei, L; Qiu, D; Fleischer, C; Oshinski, J N

    2016-01-01

    BACKGROUND AND PURPOSE Applications for non-invasive biological temperature monitoring are widespread in biomedicine, and of particular interest in the context of brain temperature regulation, where traditionally costly and invasive monitoring schemes limit their applicability in many settings. Brain thermal regulation therefore remains controversial, motivating the development of non-invasive approaches such as temperature-sensitive NMR phenomena. The purpose of this work was to compare the utility of competing approaches to MR thermometry (MRT) employing proton resonance frequency chemical shift. Three methodologies were tested, hypothesizing the feasibility of a fast and accurate approach to chemical shift thermometry, in a phantom study at 3.0 Tesla. MATERIALS AND METHODS A conventional, paired approach (DIFF-1), an accelerated single-scan approach (DIFF-2), and a new, further accelerated strategy (DIFF-3) were tested. Phantom temperatures were modulated during real-time fiber optic temperature monitoring, with MRT derived simultaneously from temperature-sensitive changes in the water proton chemical shift (~0.01 ppm/°C). MRT was subsequently performed in a series of in vivo non-human primate experiments under physiologic and ischemic conditions testing its reproducibility and overall performance. RESULTS Chemical shift thermometry demonstrated excellent agreement with phantom temperatures for all three approaches (DIFF-1 linear regression R2=0.994, p<0.001, acquisition time 4 min 40 s; DIFF-2 R2=0.996, p<0.001, acquisition time 4 min; DIFF-3 R2=0.998, p<0.001, acquisition time 40 s). CONCLUSION These findings confirm the comparability in performance of three competing approaches MRT, and present in vivo applications under physiologic and ischemic conditions in a primate stroke model. PMID:25655874

  6. The effect of multiple processing and re-use on orthodontic mini-screw torque values

    PubMed Central

    Noorollahian, Saeed; Alavi, Shiva; Rafiei, Elahe

    2015-01-01

    Background: Reusing orthodontic mini-screws would reduce treatment cost and lead to more use of mini-screws and improvement of orthodontic treatments. This study has assessed the effects of reprocessing and reusing the titanium mini-screws on their maximum insertion, removal and fracture torque (FT). Materials and Methods: In this experimental study, 20 titanium mini-screws (1.6-mm × 8-mm) were randomly divided into two equal groups. In the test group, the screws were first sterilized by autoclave and then their FT was assessed. In the control group, FT was assessed after 5 times of insertion, cleaning, processing (37% phosphoric acid for 10 min, 5.25% sodium hypochlorite for 30 min) and sterilizing with autoclave. The maximum insertion and removal torque values were compared using the repeated measure ANOVA and the FT data were analyzed by the t-test. The data were analyzed using the SPSS software (version 13.0) and the significance was set on 0.05. Results: The paired t-test for maximum insertion torque (MIT) showed that MIT1 was significantly lower than other MIT values (P = 0.02) and also MIT2 was significantly higher than MIT5 (P = 0.01), but other MIT values had no significant differences. The paired t-test for maximum removal torque (MRT) showed that only MRT2 was significantly higher than other MRT values (except MRT1) (P = 0.046). Regarding FT, the t-test showed that there was no significant difference between FT0 and FT5 (P = 0.485). Conclusion: Within limitations of this study, five time insertion, cleaning, processing and steam sterilization had no significant negative effect on insertion, removal and FT of the mini-screws. PMID:26005464

  7. Digesta retention patterns of solute and different-sized particles in camelids compared with ruminants and other foregut fermenters.

    PubMed

    Dittmann, Marie T; Runge, Ullrich; Ortmann, Sylvia; Lang, Richard A; Moser, Dario; Galeffi, Cordula; Schwarm, Angela; Kreuzer, Michael; Clauss, Marcus

    2015-07-01

    The mean retention times (MRT) of solute or particles in the gastrointestinal tract and the forestomach (FS) are crucial determinants of digestive physiology in herbivores. Besides ruminants, camelids are the only herbivores that have evolved rumination as an obligatory physiological process consisting of repeated mastication of large food particles, which requires a particle sorting mechanism in the FS. Differences between camelids and ruminants have hardly been investigated so far. In this study we measured MRTs of solute and differently sized particles (2, 10, and 20 mm) and the ratio of large-to-small particle MRT, i.e. the selectivity factors (SF(10/2mm), SF(20/2mm), SF(20/10mm)), in three camelid species: alpacas (Vicugna pacos), llamas (Llama glama), and Bactrian camels (Camelus bactrianus). The camelid data were compared with literature data from ruminants and non-ruminant foregut fermenters (NRFF). Camelids and ruminants both had higher SF(10/2mm)FS than NRFF, suggesting convergence in the function of the FS sorting mechanism in contrast to NRFF, in which such a sorting mechanism is absent. The SF(20/10mm)FS did not differ between ruminants and camelids, indicating that there is a particle size threshold of about 1 cm in both suborders above which particle retention is not increased. Camelids did not differ from ruminants in MRT(2mm)FS, MRTsoluteFS, and the ratio MRT(2mm)FS/MRTsoluteFS, but they were more similar to 'cattle-' than to 'moose-type' ruminants. Camelids had higher SF(10/2mm)FS and higher SF(20/2mm)FS than ruminants, indicating a potentially slower particle sorting in camelids than in ruminants, with larger particles being retained longer in relation to small particles.

  8. The effect of size and density on the mean retention time of particles in the reticulorumen of cattle ( Bos primigenius f. taurus), muskoxen ( Ovibos moschatus) and moose ( Alces alces).

    PubMed

    Clauss, Marcus; Lechner, Isabel; Barboza, Perry; Collins, William; Tervoort, Theo A; Südekum, Karl-Heinz; Codron, Daryl; Hummel, Jürgen

    2011-02-01

    Particle passage from the reticulorumen (RR) depends on particle density and size. Forage particle density and size are related and change over time in the RR. Particle density mainly influences sorting in the reticulum, whereas particle size influences particle retention in the fibre mat of stratified rumen contents ('filter-bed' effect). We investigated these effects independently, by inserting plastic particles of different sizes (1, 10 and 20 mm) and densities (1·03, 1·20 and 1·44 mg/ml) in the RR of cattle (Bos primigenius f. taurus) as a pilot study, and of muskoxen (Ovibos moschatus; n 4) and moose (Alces alces; n 2) both fed two diets (browse and grass). Faeces were analysed for plastic residues for 13 d after dosing to calculate mean retention times (MRT). The results confirmed previous findings of differences in absolute MRT between species. Comparing muskoxen with moose, there was no difference in the effect of particle density on the MRT between species but particle size had a more pronounced effect on the MRT in muskoxen than in moose. This indicated a stronger 'filter-bed effect' in muskoxen, in accord with the reports of stratified RR contents in this species v. the absence of RR content stratification in moose. Low-density particles were retained longer in both species fed on grass diets, indicating a contribution of forage type to the 'filter-bed effect'. The results indicate that retention based on particle size may differ between ruminant species, depending on the presence of a fibre mat in the RR, whereas the density-dependent mechanism of sedimentation in the RR is rather constant across species.

  9. Simulations of Bingham plastic flows with the multiple-relaxation-time lattice Boltzmann model

    NASA Astrophysics Data System (ADS)

    Chen, SongGui; Sun, QiCheng; Jin, Feng; Liu, JianGuo

    2014-03-01

    Fresh cement mortar is a type of workable paste, which can be well approximated as a Bingham plastic and whose flow behavior is of major concern in engineering. In this paper, Papanastasiou's model for Bingham fluids is solved by using the multiplerelaxation-time lattice Boltzmann model (MRT-LB). Analysis of the stress growth exponent m in Bingham fluid flow simulations shows that Papanastasiou's model provides a good approximation of realistic Bingham plastics for values of m > 108. For lower values of m, Papanastasiou's model is valid for fluids between Bingham and Newtonian fluids. The MRT-LB model is validated by two benchmark problems: 2D steady Poiseuille flows and lid-driven cavity flows. Comparing the numerical results of the velocity distributions with corresponding analytical solutions shows that the MRT-LB model is appropriate for studying Bingham fluids while also providing better numerical stability. We further apply the MRT-LB model to simulate flow through a sudden expansion channel and the flow surrounding a round particle. Besides the rich flow structures obtained in this work, the dynamics fluid force on the round particle is calculated. Results show that both the Reynolds number Re and the Bingham number Bn affect the drag coefficients C D , and a drag coefficient with Re and Bn being taken into account is proposed. The relationship of Bn and the ratio of unyielded zone thickness to particle diameter is also analyzed. Finally, the Bingham fluid flowing around a set of randomly dispersed particles is simulated to obtain the apparent viscosity and velocity fields. These results help simulation of fresh concrete flowing in porous media.

  10. Detecting the impact of bank and channel modification on invertebrate communities in Mediterranean temporary streams (Sardinia, SW Italy).

    PubMed

    Buffagni, Andrea; Tenchini, Roberta; Cazzola, Marcello; Erba, Stefania; Balestrini, Raffaella; Belfiore, Carlo; Pagnotta, Romano

    2016-09-15

    We hypothesized that reach-scale, bank and channel modification would impact benthic communities in temporary rivers of Sardinia, when pollution and water abstraction are not relevant. A range of variables were considered, which include both artificial structures/alterations and natural features observed in a stream reach. Multivariate regression trees (MRT) were used to assess the effects of the explanatory variables on invertebrate assemblages and five groups, characterized by different habitat modification and/or features, were recognized. Four node variables determined the splits in the MRT analysis: channel reinforcement, tree-related bank and channel habitats, channel modification and bank modification. Continuity of trees in the river corridor diverged among MRT groups and significant differences among groups include presence of alders, extent of channel shading and substrate diversity. Also, the percentage of in-stream organic substrates, in particular CPOM/Xylal, showed highly significant differences among groups. For practical applications, thresholds for the extent of channel reinforcement (40%) and modification (10%) and for bank alteration (≈30%) were provided, that can be used to guide the implementation of restoration measures. In moderately altered river reaches, a significant extent of tree-related habitats (≈5%) can noticeably mitigate the effects of morphological alteration on aquatic invertebrates. The outcomes highlight the importance of riparian zone management as an opportune, achievable prospect in the restoration of Mediterranean temporary streams. The impact of bank and channel modification on ecological status (sensu WFD) was investigated and the tested benthic metrics, especially those based on abundance data, showed legible differences among MRT groups. Finally, bank and channel modification appears to be a potential threat for the conservation of a few Sardo-Corsican endemic species. The introduction of management criteria that

  11. Testosterone levels and mental rotation performance in Chinese men.

    PubMed

    Yang, Chi-Fu Jeffrey; Hooven, Carole K; Boynes, Matthew; Gray, Peter B; Pope, Harrison G

    2007-03-01

    Males achieve markedly higher scores than females on mental rotation tests (MRTs). Therefore, it might be hypothesized that, within groups of males, testosterone levels modulate MRT performance. However, studies of this relationship have yielded inconsistent results. Notably, a recent study of 28 American men, using the computerized Shepard and Metzler MRT (SM), found significant associations between salivary testosterone levels and the intercepts of the functions relating response time and error rate to the angular disparity between comparison objects. Conversely, a study of 35 British men, using the same methodology, found no such associations. We attempted a cross-cultural replication of these studies, in which we obtained salivary testosterone levels, together with performance measures on the SM, from 92 heterosexual right-handed men, aged 21-38, in Beijing, China. We hypothesized that Chinese men might perform more slowly and carefully than Western men on this test (which imposes no time limitations), but that associations of testosterone levels with performance, if real, should nevertheless be detectable across cultures. We found that the Chinese men indeed displayed significantly longer response times than the American men, although the Chinese men were equally accurate. Interestingly, testosterone was significantly associated with the slope of the response time function in Chinese men, whereas the earlier American study had found that testosterone was associated with the intercept, but not the slope, of this function. These observations suggest that differing cultural values regarding speed and accuracy may influence MRT performance--and that these values must be considered in future studies of testosterone and MRT measures. PMID:17292367

  12. The evidence base for the use of internal dosimetry in the clinical practice of molecular radiotherapy.

    PubMed

    Strigari, Lidia; Konijnenberg, Mark; Chiesa, Carlo; Bardies, Manuel; Du, Yong; Gleisner, Katarina Sjögreen; Lassmann, Michael; Flux, Glenn

    2014-10-01

    Molecular radiotherapy (MRT) has demonstrated unique therapeutic advantages in the treatment of an increasing number of cancers. As with other treatment modalities, there is related toxicity to a number of organs at risk. Despite the large number of clinical trials over the past several decades, considerable uncertainties still remain regarding the optimization of this therapeutic approach and one of the vital issues to be answered is whether an absorbed radiation dose-response exists that could be used to guide personalized treatment. There are only limited and sporadic data investigating MRT dosimetry. The determination of dose-effect relationships for MRT has yet to be the explicit aim of a clinical trial. The aim of this article was to collate and discuss the available evidence for an absorbed radiation dose-effect relationships in MRT through a review of published data. Based on a PubMed search, 92 papers were found. Out of 79 studies investigating dosimetry, an absorbed dose-effect correlation was found in 48. The application of radiobiological modelling to clinical data is of increasing importance and the limited published data on absorbed dose-effect relationships based on these models are also reviewed. Based on National Cancer Institute guideline definition, the studies had a moderate or low rate of clinical relevance due to the limited number of studies investigating overall survival and absorbed dose. Nevertheless, the evidence strongly implies a correlation between the absorbed doses delivered and the response and toxicity, indicating that dosimetry-based personalized treatments would improve outcome and increase survival.

  13. Malignant rhabdoid tumor of the floor of mouth: first reported case in the oral cavity of an adult.

    PubMed

    Wetzel, Stephanie L; Kerpel, Stanley; Reich, Renee F; Freedman, Paul D

    2015-06-01

    Malignant rhabdoid tumors (MRTs) are exceedingly rare lesions. To our knowledge, only 2 cases have been reported in the oral cavity, with both examples occurring in infants. The current case is the third reported case of MRT of the oral cavity and the first reported case to occur in an adult at this location. The following report describes the clinical, histologic and immunohistochemical features of this tumor.

  14. Objective assessment of drowsiness and reaction time during intermittent Ramadan fasting in young men: a case-crossover study

    PubMed Central

    2013-01-01

    Background Ramadan fasting and its attendant lifestyle changes induce changes in the circadian rhythm and in associated physiological and metabolic functions. Previous studies that have assessed psychomotor performance during Ramadan fasting have reported conflicting results. Therefore, we designed this study to objectively assess the effects of intermittent fasting during and outside Ramadan (to control for lifestyle changes) on drowsiness, blink total duration and mean reaction time (MRT) test while controlling for potential confounders. Methods Eight healthy volunteers with a mean age of 25.3 ± 2.9 years and a mean body mass index (BMI) of 23.4 ± 3.2 kg/m2 reported to the sleep laboratory on four occasions for polysomnography (PSG) and drowsiness and psychomotor assessments as follows: 1) adaptation; 2) 4 weeks before Ramadan while performing the Islamic fasting for 1 week (baseline fasting) (BLF); 3) 1 week before Ramadan (non-fasting baseline) (BL); and 4) during the second week of Ramadan while fasting (Ramadan). OPTALERT™ was used to objectively assess daytime drowsiness using the Johns Drowsiness Scale (JDS), and blink total duration and a visual reaction time test were used to assess MRT. Results Rapid eye movement (REM) sleep percentage was significantly lower at BLF (17.7 ± 8.1%) and at Ramadan (18.6 ± 10.7%) compared with BL (25.6 ± 4.8%) (p < 0.05). There were no significant differences between JDS scores and blink total duration during the two test periods in BL, BLF and Ramadan. There were no significant changes in MRT during BL, BLF and Ramadan. Conclusions Under controlled conditions of fixed light/dark exposure, caloric intake, sleep/wake schedule and sleep quality, the Islamic intermittent fasting has no impact on drowsiness and vigilance as measured by the JDS, total blink duration and MRT. PMID:23937904

  15. Modeling, measuring, and mitigating instability growth in liner implosions on Z

    NASA Astrophysics Data System (ADS)

    Peterson, Kyle

    2015-11-01

    Electro-thermal instabilities result from non-uniform heating due to temperature dependence in the conductivity of a material. In this talk, we will discuss the role of electro-thermal instabilities on the dynamics of magnetically accelerated implosion systems. We present simulations that show electro-thermal instabilities form immediately after the surface material of a conductor melts and can act as a significant seed to subsequent magneto-Rayleigh-Taylor (MRT) instability growth. We discuss measurement results from experiments performed on Sandia National Laboratories Z accelerator to investigate signatures of electro-thermal instability growth on well-characterized initially solid aluminum or beryllium rods driven with a 20 MA, 100 ns risetime current pulse. These measurements show good agreement with electro-thermal instability simulations and exhibit larger instability growth than can be explained by MRT theory alone. Recent experiments have confirmed simulation predictions of dramatically reduced instability growth in solid metallic rods when thick dielectric coatings are used to mitigate density perturbations arising from the electro-thermal instability. These results provide further evidence that the inherent surface roughness of the target is not the dominant seed for the MRT instability, in contrast with most inertial confinement fusion approaches. These results suggest a new technique for substantially reducing the integral MRT growth in magnetically driven implosions. Indeed, recent results on the Z facility with 100 km/s Al and Be liner implosions show substantially reduced growth. These new results include axially magnetized, CH-coated beryllium liner radiographs in which the inner liner surface is observed to be remarkably straight and uniform at a radius of about 120 microns (convergence ratio ~20). Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under

  16. Microbeam radiation therapy: A Monte Carlo study of the influence of the source, multislit collimator, and beam divergence on microbeams

    SciTech Connect

    Nettelbeck, H.; Takacs, G. J.; Lerch, M. L. F.; Rosenfeld, A. B.

    2009-02-15

    Microbeam radiation therapy (MRT) is a new oncology method currently under development for the treatment of inoperable pediatric brain tumors. Monte Carlo simulation, or the computational study of radiation transport in matter, is often used in radiotherapy to theoretically estimate the dose required for treatment. However, its potential use in MRT dose planning systems is currently hindered by the significant discrepancies that have been observed between measured and theoretical dose and the PVDR (peak to valley dose ratio). The need to resolve these discrepancies is driven by the desirability of making MRT available to humans in the next few years. This article aims to resolve some of the discrepancies by examining the simplifications adopted in previous MRT Monte Carlo studies, such as the common practice of commencing microbeam transport on the surface of the target which neglects the influence of the distributed synchrotron source, multislit collimator, and the beam divergence between them. This article uses PENELOPE Monte Carlo simulation to investigate the influence of these beamline components upstream of the target on the lateral dose profiles and PVDRs of an array of 25 microbeams. It also compares the dose profiles and PVDRs of a microbeam array produced from a single simulation (full array) to those produced from the superposition of a single microbeam profile (sup array). The effect of modeling the distributed source and the beam divergence was an increase in the absorbed dose in the penumbral and valley regions of the microbeam profiles. Inclusion of the multislit collimator resulted in differences of up to 5 {mu}m in the FWHM of microbeam profiles across the array, which led to minor variations in the corresponding PVDR yields.

  17. Verbesserung der Prozessbedingungen beim Einlippentiefbohren durch unterschiedliche Formen der Vorschubmodulation

    NASA Astrophysics Data System (ADS)

    Eisseler, Rocco

    Das Tiefbohren mit Einlippenwerkzeugen ist bei vielen Anwendungen das Verfahren der ersten Wahl, vor allem wenn kleine und kleinste Bohrungsdurchmesser, ein sehr großes Verhältnis zwischen Bohrtiefe und Durchmesser (l/D) und eine hohe Bearbeitungsqualität gefordert werden. Der erreichbare Durchmesserbereich des Verfahrens liegt zwischen D = 0,5 mm und 40 mm, wobei die möglichen Bohrtiefen von l = 3 x D bis 250 x D reichen. Diese Werte beziehen sich auf das Vollbohren, beim Aufbohren können noch größere Durchmesser erreicht werden [1]. Die erreichbare Oberflächenqualität ist so hoch, dass in den meisten Fällen auf eine nachfolgende Feinbearbeitung verzichtet werden kann.

  18. On the Vacuum-Interaction of Two Parallel Cosmic Strings

    NASA Astrophysics Data System (ADS)

    Bordag, M.

    Cosmic strings are well known solutions of the Einstein equations. In classical physics there is no interaction between such strings. In quantum physics there is an interaction due to vacuum fluctuations like the well known Casimir effect. The interaction energy is calculated in the case of two parallel cosmic strings and shows an attractive force between them.Translated AbstractZur Vakuumwechselwirkung zweier paralleler kosmischer StringsKosmische Strings sind wohlbekannte Lösungen der Einsteinschen Gleichungen. Im Rahmen der klassischen Physik gibt es keine Wechselwirkungen zwischen den Strings. In der Quantenphysik erhalten wir eine Wechselwirkung infolge Vakuumfluktuationen wie im Fall des Casimir-Effekts. Wir berechnen die Wechselwirkungsenergie für den Fall zweier paralleler kosmischer Strings und zeigen, daß eine anziehende Kraft zwischen ihnen besteht.

  19. Internet-Einzelhandel bei Multi-Channel-Unternehmen

    NASA Astrophysics Data System (ADS)

    Breidenbach, Petra; Rauh, Jürgen

    Die unterschiedliche Bedeutung des Internets zu Informations- und Kaufzwecken konnte anhand von quantitativen Online-Befragungen von Konsumenten bei Multi-Channel-Anbietern verschiedener Bedarfsfristigkeitsstufen aufgezeigt werden. Insbesondere der Wechsel zwischen verschiedenen Vertriebskanälen (Multi-Channel-Verhalten) ist sowohl mit verkehrsubstituierenden als auch verkehrgenerierenden Effekten verbunden.Dabei können von der reinen Virtualisierung von Konsumtätigkeiten durch das Internet bei Informationsprozessen Einsparungspotenziale von Informations-(such-)-Verkehr abgeleitet werden. Einsparungseffekte aufgrund von Online-Käufen stehen in Zusammenhang mit den Wechselwirkungen zwischen unternehmerischen Maßnahmen sowie vertriebskanal- und produktspezifische Akzeptanz der Konsumenten zur Nutzung des Internets. Die siedlungsstrukturelle Einordnung der Wohnorte der Konsumenten sowie unternehmerische Vertriebsnetzstrukturensind bei der Bewertung verkehrlicher Wirkung von hoher Relevanz.

  20. Total enthalpy-based lattice Boltzmann method with adaptive mesh refinement for solid-liquid phase change

    NASA Astrophysics Data System (ADS)

    Huang, Rongzong; Wu, Huiying

    2016-06-01

    A total enthalpy-based lattice Boltzmann (LB) method with adaptive mesh refinement (AMR) is developed in this paper to efficiently simulate solid-liquid phase change problem where variables vary significantly near the phase interface and thus finer grid is required. For the total enthalpy-based LB method, the velocity field is solved by an incompressible LB model with multiple-relaxation-time (MRT) collision scheme, and the temperature field is solved by a total enthalpy-based MRT LB model with the phase interface effects considered and the deviation term eliminated. With a kinetic assumption that the density distribution function for solid phase is at equilibrium state, a volumetric LB scheme is proposed to accurately realize the nonslip velocity condition on the diffusive phase interface and in the solid phase. As compared with the previous schemes, this scheme can avoid nonphysical flow in the solid phase. As for the AMR approach, it is developed based on multiblock grids. An indicator function is introduced to control the adaptive generation of multiblock grids, which can guarantee the existence of overlap area between adjacent blocks for information exchange. Since MRT collision schemes are used, the information exchange is directly carried out in the moment space. Numerical tests are firstly performed to validate the strict satisfaction of the nonslip velocity condition, and then melting problems in a square cavity with different Prandtl numbers and Rayleigh numbers are simulated, which demonstrate that the present method can handle solid-liquid phase change problem with high efficiency and accuracy.

  1. Digesta kinetics in gazelles in comparison to other ruminants: Evidence for taxon-specific rumen fluid throughput to adjust digesta washing to the natural diet.

    PubMed

    Dittmann, Marie T; Hummel, Jürgen; Hammer, Sven; Arif, Abdi; Hebel, Christiana; Müller, Dennis W H; Fritz, Julia; Steuer, Patrick; Schwarm, Angela; Kreuzer, Michael; Clauss, Marcus

    2015-07-01

    Digesta flow plays an important role in ruminant digestive physiology. We measured the mean retention time (MRT) of a solute and a particle marker in the gastrointestinal tract (GIT) and the reticulorumen (RR) of five gazelles and one dikdik species. Species-specific differences were independent from body mass (BM) or food intake. Comparative evaluations (including up to 31 other ruminant species) indicate that MRT GIT relate positively to BM, and are less related to feeding type (the percentage of grass in the natural diet, %grass) than MRT RR. The MRTparticleRR is related to BM and (as a trend) %grass, matching a higher RR capacity with increasing BM in grazers compared to browsers. MRTsoluteRR is neither linked to BM nor to %grass but shows a consistent phylogenetic signal. Selectivity factors (SF; MRTparticle/MRTsolute, proxies for the degree of digesta washing) are positively related to %grass, with a threshold effect, where species with >20% grass have higher SF. These findings suggest that in different ruminant taxa, morphophysiological adaptations controlling MRTsoluteRR evolved to achieve a similar SF RR in relation to a %grass threshold. A high SF could facilitate an increased microbial yield from the forestomach. Reasons for variation in SF above the %grass threshold might represent important drivers of ruminant diversification and await closer investigation. PMID:25637787

  2. Creating a Three-Parent Child: An Educational Paradigm for the Responsible Conduct of Research

    PubMed Central

    Fischbach, Ruth L.; Benston, Shawna; Loike, John D.

    2014-01-01

    The field of assisted reproduction is renowned for its remarkable advances and constant pushing forward of research boundaries in an effort to offer innovative and effective methods for enhancing fertility. Accompanying these advances, however, are physiological, psychological, and bioethical consequences that must be considered. These concomitant advances and consequences make assisted reproduction an excellent educational paradigm for inculcating responsible conduct in both research and clinical practice. Ultimately, responsible conduct rests on the ethical researcher and clinician. Here, we present the as-yet unapproved, contentious assisted reproductive technology of mitochondrial replacement transfer (MRT) as an ideal educational platform to foster the responsible conduct of research by advancing dialogue among multi-disciplinary scholars, researchers, and students. Using a likely future case, we present the basic science, legal, and ethical considerations, and the pedagogical principles and strategies for using MRT as an effective educational paradigm. Society will benefit when the ethical issues inherent in creating children with three genetic parents as well as germline interference are discussed across multiple academic levels that include researchers, legal experts, bioethicists, and government-appointed commissions. Furthermore, undergraduate and graduate students should be included because they will likely determine the ethical fates of these biotechnologies. While emerging assisted reproduction technologies such as MRT are highly complex and will take years to be readily available for patients in need, now is the time to consider their scientific, legal, ethical, and cultural/religious implications for ensuring the responsible conduct of research. PMID:25574276

  3. You Should Be the Specialist! Weak Mental Rotation Performance in Aviation Security Screeners - Reduced Performance Level in Aviation Security with No Gender Effect.

    PubMed

    Krüger, Jenny K; Suchan, Boris

    2016-01-01

    Aviation security screeners analyze a large number of X-ray images per day and seem to be experts in mentally rotating diverse kinds of visual objects. A robust gender-effect that men outperform women in the Vandenberg & Kuse mental rotation task has been well documented over the last years. In addition it has been shown that training can positively influence the overall task-performance. Considering this, the aim of the present study was to investigate whether security screeners show better performance in the Mental Rotation Test (MRT) independently of gender. Forty-seven security screeners of both sexes from two German airports were examined with a computer based MRT. Their performance was compared to a large sample of control subjects. The well-known gender-effect favoring men on mental rotation was significant within the control group. However, the security screeners did not show any sex differences suggesting an effect of training and professional performance. Surprisingly this specialized group showed a lower level of overall MRT performance than the control participants. Possible aviation related influences such as secondary effects of work-shift or expertise which can cumulatively cause this result are discussed. PMID:27014142

  4. Partitioned fluid-solid coupling for cardiovascular blood flow: validation study of pressure-driven fluid-domain deformation.

    PubMed

    Krittian, Sebastian; Schenkel, Torsten; Janoske, Uwe; Oertel, Herbert

    2010-08-01

    The Karlsruhe Heart Model (KaHMo) is a patient-specific simulation tool for a three-dimensional blood flow evaluation inside the human heart. Whereas KaHMo MRT is based on geometry movement identified from MRT data, KaHMo FSI allows the consideration of structural properties and the analysis of FSI. Previous investigations by Oertel et al. have shown the ability of KaHMo to gain insight into different intra-ventricular fluid mechanics of both healthy and diseased hearts. However, the in vivo validation of the highly dynamic cavity flow pattern has been a challenging task in recent years. As a first step, the focus of this study is on an artificial ventricular experiment, derived from real heart anatomy. Fluid domain deformation and intra-ventricular flow dynamics are enforced by an outer surface pressure distribution. The pure geometrical representation of KaHMo MRT can now be complemented by constitutive properties, pressure forces, and interaction effects using KaHMo FSI's partitioned code-coupling approach. For the first time, fluid domain deformation and intra-ventricular flow of KaHMo FSI has been compared with experimental data. With a good overall agreement, the proof of KaHMo's validity represents an important step from feasibility study toward patient-specific analysis.

  5. Conceptualization and validation of an open-source closed-loop deep brain stimulation system in rat.

    PubMed

    Wu, Hemmings; Ghekiere, Hartwin; Beeckmans, Dorien; Tambuyzer, Tim; van Kuyck, Kris; Aerts, Jean-Marie; Nuttin, Bart

    2015-01-01

    Conventional deep brain stimulation (DBS) applies constant electrical stimulation to specific brain regions to treat neurological disorders. Closed-loop DBS with real-time feedback is gaining attention in recent years, after proved more effective than conventional DBS in terms of pathological symptom control clinically. Here we demonstrate the conceptualization and validation of a closed-loop DBS system using open-source hardware. We used hippocampal theta oscillations as system input, and electrical stimulation in the mesencephalic reticular formation (mRt) as controller output. It is well documented that hippocampal theta oscillations are highly related to locomotion, while electrical stimulation in the mRt induces freezing. We used an Arduino open-source microcontroller between input and output sources. This allowed us to use hippocampal local field potentials (LFPs) to steer electrical stimulation in the mRt. Our results showed that closed-loop DBS significantly suppressed locomotion compared to no stimulation, and required on average only 56% of the stimulation used in open-loop DBS to reach similar effects. The main advantages of open-source hardware include wide selection and availability, high customizability, and affordability. Our open-source closed-loop DBS system is effective, and warrants further research using open-source hardware for closed-loop neuromodulation. PMID:25897892

  6. Soil nitrogen dynamics within profiles of a managed moist temperate forest chronosequence consistent with long-term harvesting-induced losses

    NASA Astrophysics Data System (ADS)

    Kellman, Lisa; Kumar, Sanjeev; Diochon, Amanda

    2014-07-01

    This study investigates whether clear-cut forest harvesting leads to alterations in the decadal-scale biogeochemical nitrogen (N) cycles of moist temperate forest ecosystems. Using a harvested temperate red spruce (Picea rubens Sarg.) forest chronosequence in Nova Scotia, Canada, representing <1 to >80 year old postharvest conditions, alongside a reference old-growth (125+ year old) site with no documented history of disturbance, we examine harvesting-related changes in soil N pools and fluxes. Specifically, we quantify soil N storage with depth and age across the forest chronosequence, examine changes in physical fractions and δ15N of soil N through depth and time, and quantify gross soil N transformation rates through depth and time using a 15N isotope dilution technique. Our findings point to a large loss of total N in the soil pool, particularly within the deep soil (>20 cm) and organomineral fractions. A pulse of available mineralized N (as ammonium) was observed following harvesting (mean residence time (MRT) > 6 days), but its MRT dropped to <1 day 80 years following harvesting, in contrast to the MRT of 2-3 days observed in the reference old-growth forest site. These mineralization patterns coupled with inferred leaching losses to groundwater are consistent with storage estimates that suggest soil N may not reaccrue for almost a century following this disturbance.

  7. Multi-gradient echo MR thermometry for monitoring of the near-field area during MR-guided high intensity focused ultrasound heating.

    PubMed

    Lam, Mie K; de Greef, Martijn; Bouwman, Job G; Moonen, Chrit T W; Viergever, Max A; Bartels, Lambertus W

    2015-10-01

    The multi-gradient echo MR thermometry (MGE MRT) method is proposed to use at the interface of the muscle and fat layers found in the abdominal wall, to monitor MR-HIFU heating. As MGE MRT uses fat as a reference, it is field-drift corrected. Relative temperature maps were reconstructed by subtracting absolute temperature maps. Because the absolute temperature maps are reconstructed of individual scans, MGE MRT provides the flexibility of interleaved mapping of temperature changes between two arbitrary time points. The method's performance was assessed in an ex vivo water bath experiment. An ex vivo HIFU experiment was performed to show the method's ability to monitor heating of consecutive HIFU sonications and to estimate cooling time constants, in the presence of field drift. The interleaved use between scans of a clinical protocol was demonstrated in vivo in a patient during a clinical uterine fibroid treatment. The relative temperature measurements were accurate (mean absolute error 0.3 °C) and provided excellent visualization of the heating of consecutive HIFU sonications. Maps were reconstructed of estimated cooling time constants and mean ROI values could be well explained by the applied heating pattern. Heating upon HIFU sonication and subsequent cooling could be observed in the in vivo demonstration.

  8. Characterization of surface and ground water δ18O seasonal variation and its use for estimating groundwater residence times

    USGS Publications Warehouse

    Reddy, Michael M.; Schuster, Paul F.; Kendall, Carol; Reddy, Micaela B.

    2006-01-01

    18O is an ideal tracer for characterizing hydrological processes because it can be reliably measured in several watershed hydrological compartments. Here, we present multiyear isotopic data, i.e. 18O variations (δ18O), for precipitation inputs, surface water and groundwater in the Shingobee River Headwaters Area (SRHA), a well-instrumented research catchment in north-central Minnesota. SRHA surface waters exhibit δ18O seasonal variations similar to those of groundwaters, and seasonal δ18O variations plotted versus time fit seasonal sine functions. These seasonal δ18O variations were interpreted to estimate surface water and groundwater mean residence times (MRTs) at sampling locations near topographically closed-basin lakes. MRT variations of about 1 to 16 years have been estimated over an area covering about 9 km2 from the basin boundary to the most downgradient well. Estimated MRT error (±0·3 to ±0·7 years) is small for short MRTs and is much larger (±10 years) for a well with an MRT (16 years) near the limit of the method. Groundwater transit time estimates based on Darcy's law, tritium content, and the seasonal δ18O amplitude approach appear to be consistent within the limits of each method. The results from this study suggest that use of the δ18O seasonal variation method to determine MRTs can help assess groundwater recharge areas in small headwaters catchments.

  9. The key to success in elite athletes? Explicit and implicit motor learning in youth elite and non-elite soccer players.

    PubMed

    Verburgh, L; Scherder, E J A; van Lange, P A M; Oosterlaan, J

    2016-09-01

    In sports, fast and accurate execution of movements is required. It has been shown that implicitly learned movements might be less vulnerable than explicitly learned movements to stressful and fast changing circumstances that exist at the elite sports level. The present study provides insight in explicit and implicit motor learning in youth soccer players with different expertise levels. Twenty-seven youth elite soccer players and 25 non-elite soccer players (aged 10-12) performed a serial reaction time task (SRTT). In the SRTT, one of the sequences must be learned explicitly, the other was implicitly learned. No main effect of group was found for implicit and explicit learning on mean reaction time (MRT) and accuracy. However, for MRT, an interaction was found between learning condition, learning phase and group. Analyses showed no group effects for the explicit learning condition, but youth elite soccer players showed better learning in the implicit learning condition. In particular, during implicit motor learning youth elite soccer showed faster MRTs in the early learning phase and earlier reached asymptote performance in terms of MRT. Present findings may be important for sports because children with superior implicit learning abilities in early learning phases may be able to learn more (durable) motor skills in a shorter time period as compared to other children.

  10. Microbeam radiation therapy

    NASA Astrophysics Data System (ADS)

    Laissue, Jean A.; Lyubimova, Nadia; Wagner, Hans-Peter; Archer, David W.; Slatkin, Daniel N.; Di Michiel, Marco; Nemoz, Christian; Renier, Michel; Brauer, Elke; Spanne, Per O.; Gebbers, Jan-Olef; Dixon, Keith; Blattmann, Hans

    1999-10-01

    The central nervous system of vertebrates, even when immature, displays extraordinary resistance to damage by microscopically narrow, multiple, parallel, planar beams of x rays. Imminently lethal gliosarcomas in the brains of mature rats can be inhibited and ablated by such microbeams with little or no harm to mature brain tissues and neurological function. Potentially palliative, conventional wide-beam radiotherapy of malignant brain tumors in human infants under three years of age is so fraught with the danger of disrupting the functional maturation of immature brain tissues around the targeted tumor that it is implemented infrequently. Other kinds of therapy for such tumors are often inadequate. We suggest that microbeam radiation therapy (MRT) might help to alleviate the situation. Wiggler-generated synchrotron x-rays were first used for experimental microplanar beam (microbeam) radiation therapy (MRT) at Brookhaven National Laboratory's National Synchrotron Light Source in the early 1990s. We now describe the progress achieved in MRT research to date using immature and adult rats irradiated at the European Synchrotron Radiation Facility in Grenoble, France, and investigated thereafter at the Institute of Pathology of the University of Bern.

  11. Multi-gradient echo MR thermometry for monitoring of the near-field area during MR-guided high intensity focused ultrasound heating

    NASA Astrophysics Data System (ADS)

    Lam, Mie K.; de Greef, Martijn; Bouwman, Job G.; Moonen, Chrit T. W.; Viergever, Max A.; Bartels, Lambertus W.

    2015-10-01

    The multi-gradient echo MR thermometry (MGE MRT) method is proposed to use at the interface of the muscle and fat layers found in the abdominal wall, to monitor MR-HIFU heating. As MGE MRT uses fat as a reference, it is field-drift corrected. Relative temperature maps were reconstructed by subtracting absolute temperature maps. Because the absolute temperature maps are reconstructed of individual scans, MGE MRT provides the flexibility of interleaved mapping of temperature changes between two arbitrary time points. The method’s performance was assessed in an ex vivo water bath experiment. An ex vivo HIFU experiment was performed to show the method’s ability to monitor heating of consecutive HIFU sonications and to estimate cooling time constants, in the presence of field drift. The interleaved use between scans of a clinical protocol was demonstrated in vivo in a patient during a clinical uterine fibroid treatment. The relative temperature measurements were accurate (mean absolute error 0.3 °C) and provided excellent visualization of the heating of consecutive HIFU sonications. Maps were reconstructed of estimated cooling time constants and mean ROI values could be well explained by the applied heating pattern. Heating upon HIFU sonication and subsequent cooling could be observed in the in vivo demonstration.

  12. Digesta kinetics in gazelles in comparison to other ruminants: Evidence for taxon-specific rumen fluid throughput to adjust digesta washing to the natural diet.

    PubMed

    Dittmann, Marie T; Hummel, Jürgen; Hammer, Sven; Arif, Abdi; Hebel, Christiana; Müller, Dennis W H; Fritz, Julia; Steuer, Patrick; Schwarm, Angela; Kreuzer, Michael; Clauss, Marcus

    2015-07-01

    Digesta flow plays an important role in ruminant digestive physiology. We measured the mean retention time (MRT) of a solute and a particle marker in the gastrointestinal tract (GIT) and the reticulorumen (RR) of five gazelles and one dikdik species. Species-specific differences were independent from body mass (BM) or food intake. Comparative evaluations (including up to 31 other ruminant species) indicate that MRT GIT relate positively to BM, and are less related to feeding type (the percentage of grass in the natural diet, %grass) than MRT RR. The MRTparticleRR is related to BM and (as a trend) %grass, matching a higher RR capacity with increasing BM in grazers compared to browsers. MRTsoluteRR is neither linked to BM nor to %grass but shows a consistent phylogenetic signal. Selectivity factors (SF; MRTparticle/MRTsolute, proxies for the degree of digesta washing) are positively related to %grass, with a threshold effect, where species with >20% grass have higher SF. These findings suggest that in different ruminant taxa, morphophysiological adaptations controlling MRTsoluteRR evolved to achieve a similar SF RR in relation to a %grass threshold. A high SF could facilitate an increased microbial yield from the forestomach. Reasons for variation in SF above the %grass threshold might represent important drivers of ruminant diversification and await closer investigation.

  13. Effect of D-mannitol on nitrogen retention, fiber digestibility and digesta transit time in adult rabbits.

    PubMed

    Min, Xiao; Li, Xiao; Hiura, Shouko; Kawasaki, Kiyonori; Xiao, Jin; Sakaguchi, Ei

    2013-07-01

    The aim of the current study was to elucidate the effect of gastrointestinal retention time of digesta on fiber digestibility in adult rabbits fed indigestible, but fermentable, sugar D-mannitol. Six adult rabbits were fed alternately a commercial diet containing 5% glucose and a diet containing D-mannitol. Total feces and urine were collected during the experimental period. Nitrogen (N) balance, digestibility of nutrients, and gastrointestinal mean retention time (MRT) were measured. The results indicated that urinary excretion was significantly lowered, whereas N retention and N accumulation rates were significantly increased in the D-mannitol group compared with the glucose group (P < 0.05). However, fecal N excretion was unaffected. Absorption of crude ash (CA) and acid detergent fiber (ADF) digestibility were significantly higher in the D-mannitol group compared with the glucose group (P < 0.05). The addition of D-mannitol to the diet did not affect the MRT of liquid digesta, but increased the MRT of solid digesta compared with the glucose group (P < 0.05). These results suggest that the addition of D-mannitol to the diet stimulates cecal bacterial growth, thereby increasing N utilization and digesta retention time.

  14. The Use of Point-of-Decision Prompts to Increase Stair Climbing in Singapore

    PubMed Central

    Sloan, Robert Alan; Haaland, Benjamin Adam; Leung, Carol; Müller-Riemenschneider, Falk

    2013-01-01

    Physical inactivity is a significant contributor to worldwide mortality and morbidity associated with non-communicable diseases. An excellent avenue to incorporate lifestyle physical activity into regular routine is to encourage the use of stairs during daily commutes. We evaluated the effectiveness of point-of-decision prompts (PODPs) in promoting the use of stairs instead of the escalators in a Singapore Mass Rapid Transit (MRT) station. We measured the number of stair climbers before the PODPs were put up, during the 4 weeks that they were in use, and 2 weeks after they were removed. Measurements at a no intervention control site were additionally taken. The use of stair-riser banners was associated with an increase in the number of people using the stairs by a factor of 1.49 (95% CI 1.34–1.64). After the banners were removed, the number of stair climbers at the experimental station dropped to slightly below baseline levels. The Singapore MRT serves a diverse multi-ethnic population with an average daily ridership of over 2 million and 88 stations island-wide. An increase of physical activity among these MRT commuters would have a large impact at the population level. Our findings can be translated into part of the national strategy to encourage an active lifestyle in Singaporeans. PMID:23296208

  15. The use of point-of-decision prompts to increase stair climbing in Singapore.

    PubMed

    Sloan, Robert Alan; Haaland, Benjamin Adam; Leung, Carol; Müller-Riemenschneider, Falk

    2013-01-01

    Physical inactivity is a significant contributor to worldwide mortality and morbidity associated with non-communicable diseases. An excellent avenue to incorporate lifestyle physical activity into regular routine is to encourage the use of stairs during daily commutes. We evaluated the effectiveness of point-of-decision prompts (PODPs) in promoting the use of stairs instead of the escalators in a Singapore Mass Rapid Transit (MRT) station. We measured the number of stair climbers before the PODPs were put up, during the 4 weeks that they were in use, and 2 weeks after they were removed. Measurements at a no intervention control site were additionally taken. The use of stair-riser banners was associated with an increase in the number of people using the stairs by a factor of 1.49 (95% CI 1.34-1.64). After the banners were removed, the number of stair climbers at the experimental station dropped to slightly below baseline levels. The Singapore MRT serves a diverse multi-ethnic population with an average daily ridership of over 2 million and 88 stations island-wide. An increase of physical activity among these MRT commuters would have a large impact at the population level. Our findings can be translated into part of the national strategy to encourage an active lifestyle in Singaporeans. PMID:23296208

  16. Dosimetry And Its Enhancement Using Gold Nanoparticles In Synchrotron Based Microbeam And Stereotactic Radiosurgery

    SciTech Connect

    Rahman, Wan Nordiana; Davidson, Robert; Geso, Moshi; Wong, Christopher James; Yagi, Naoto

    2010-07-23

    Research into the areas of synchrotron generated microbeam radiotherapy (MRT) and stereotactic radiosurgery is increasing. Such MRT techniques are showing potential of tackling some of the more difficult radiotherapy cases such as certain type of brain tumours. Two challenging aspects of these techniques are addressed in this investigation; the difficulty of dose determination and the delivery of the treatments at lower dose levels. In this research polymer gels were used as phantoms and dosimeters and cells were used to confirm outcomes. Normoxic polyacrylamide gels (nPAG) were tested as potential dosimeters for microbeam dosimetry. Following irradiation using microbeam and minibeam radiation from the BL28BU beam-line at Spring-8, Japan, the nPAG were scanned using a Raman spectroscopy technique. Dose enhancement caused by the inclusion of the gold nanoparticles (AuNPs) in the target was investigated using both cells and polymer gels. The use of AuNP could potentially reduce the dose required for the delivery of MRT. In this study it was shown that using endothelial cells with AuNPs, the minimal dose for clear cell killing along the beam line was reduced to 10 Gy. Both studies cell and gel studies indicates significant dose enhancement caused by the gold atoms in the target.

  17. The effect of insertion angle on orthodontic mini-screw torque

    PubMed Central

    Raji, Seyed Hamid; Noorollahian, Saeed; Niknam, Seyed Mohsen

    2014-01-01

    Background: Primary stability is an important factor for the clinical success of orthodontic mini-screws. The present study made an attempt to evaluate the effect of insertion angle changes on the maximum insertion and removal torque of orthodontic mini-screws. Materials and Methods: In this experimental study, 72 mini-screws (Dual Top Anchor System, Jeil, 1.6 mm diameter, 8 mm length) were used. They were randomly divided into four equal groups and inserted in poly-carbonate plates with 3 mm thickness. Then, their maximum insertion torque (MIT) and maximum removal torque (MRT) were recorded using a digital torque tester/screwdriver. Each group had a different insertion angle (90°, 75°, 60° and 45°). The data were analyzed by SPSS software (version 18) using one-way ANOVA and post-hoc Tukey's tests. The level of significance was set at 0.05. Results: The maximum MIT was observed in 45° insertion angle (14.84 Ncm) and the minimum MIT was reported in 75° insertion angle (12.66 Ncm). The maximum MRT was observed in 45° insertion angle (23.21 Ncm) and the minimum MRT was reported in the 90° insertion angle (17.43 Ncm). Conclusion: Oblique insertion of the mini-screws results in higher insertion and removal torques and probably more primary stability compared to the vertical insertion. PMID:25225557

  18. You Should Be the Specialist! Weak Mental Rotation Performance in Aviation Security Screeners – Reduced Performance Level in Aviation Security with No Gender Effect

    PubMed Central

    Krüger, Jenny K.; Suchan, Boris

    2016-01-01

    Aviation security screeners analyze a large number of X-ray images per day and seem to be experts in mentally rotating diverse kinds of visual objects. A robust gender-effect that men outperform women in the Vandenberg & Kuse mental rotation task has been well documented over the last years. In addition it has been shown that training can positively influence the overall task-performance. Considering this, the aim of the present study was to investigate whether security screeners show better performance in the Mental Rotation Test (MRT) independently of gender. Forty-seven security screeners of both sexes from two German airports were examined with a computer based MRT. Their performance was compared to a large sample of control subjects. The well-known gender-effect favoring men on mental rotation was significant within the control group. However, the security screeners did not show any sex differences suggesting an effect of training and professional performance. Surprisingly this specialized group showed a lower level of overall MRT performance than the control participants. Possible aviation related influences such as secondary effects of work-shift or expertise which can cumulatively cause this result are discussed. PMID:27014142

  19. Evaluation of the unstructured lattice Boltzmann method in porous flow simulations

    NASA Astrophysics Data System (ADS)

    Misztal, Marek; Matin, Rastin; Hernandez, Anier; Mathiesen, Joachim

    2015-11-01

    Flows in porous media are among the most challenging to simulate using the computational fluid dynamics methods, primarily due to the complex boundaries, often characterized by a very broad distribution of pore sizes. The standard (regular grid based) lattice Boltzmann method with the multi-relaxation time (MRT) collision operator is often used to simulate such flows. However, due to the lack of coupling between the positions of the computational grid nodes and the solid boundaries, the properties of the simulated flow might unnaturally vary with the fluid's viscosity, depending on the parameters of the MRT operator. This is, for instance, the case with the otherwise popular, single-relaxation time Bhatnagar-Gross-Krook (BGK) collision operator. Our focus has been on the unstructured grid based, finite element variant of the LBM. By using such approach, we can place the computational grid nodes precisely at the solid boundary. Since there is no prior work on the accuracy of this method in simulating porous flows, we perform a thorough permeability study using both BGK and MRT operators at a wide range of viscosities. We benchmark these models on artificial samples with known solutions, and further, we demonstrate the findings of our studies in the porous networks of real rocks. Predicting Petrophysical Parameters: A Project Sponsored by HTF and Maersk Oil and Gas.

  20. Mechanical and Histological Effects of Resorbable Blasting Media Surface Treatment on the Initial Stability of Orthodontic Mini-Implants

    PubMed Central

    2016-01-01

    Introduction. This study aimed to evaluate the effects of resorbable blasting media (RBM) treatment on early stability of orthodontic mini-implants by mechanical, histomorphometric, and histological analyses. Methods. Ninety-six (64 for mechanical study and 32 for histological study and histomorphometric analysis) titanium orthodontic mini-implants (OMIs) with machined (machined group) or RBM-treated (CaP) surface (RBM group) were implanted in the tibiae of 24 rabbits. Maximum initial torque (MIT) was measured during insertion, and maximum removal torque (MRT) and removal angular momentum (RAM) were measured at 2 and 4 weeks after implantation. Bone-to-implant contact (BIC) and bone area (BA) were analyzed at 4 weeks after implantation. Results. RBM group exhibited significantly lower MIT and significantly higher MRT and RAM at 2 weeks than machined group. No significant difference in MRT, RAM, and BIC between the two groups was noted at 4 weeks, although BA was significantly higher in RBM group than in machined group. RBM group showed little bone resorption, whereas machined group showed new bone formation after bone resorption. Conclusions. RBM surface treatment can provide early stability of OMIs around 2 weeks after insertion, whereas stability of machined surface OMIs may decrease in early stages because of bone resorption, although it can subsequently recover by new bone apposition. PMID:26942200

  1. Experimental Studies of the Electrothermal and Magneto-Rayleigh Taylor Instabilities on Thin Metal Foil Ablations

    NASA Astrophysics Data System (ADS)

    Steiner, Adam; Yager-Elorriaga, David; Patel, Sonal; Jordan, Nicholas; Gilgenbach, Ronald; Lau, Y. Y.

    2015-11-01

    The electrothermal instability (ETI) and magneto-Rayleigh Taylor instability (MRT) are important in the implosion of metallic liners, such as magnetized liner implosion fusion (MagLIF). The MAIZE linear transformer driver (LTD) at the University of Michigan generates 200 ns risetime-current pulses of 500 to 600 kA into Al foil liners to study plasma instabilities and implosion dynamics, most recently MRT growth on imploding cylindrical liners. A full circuit model of MAIZE, along with I-V measurements, yields time-resolved load inductance. This has enabled measurements of an effective current-carrying radius to determine implosion velocity and plasma-vacuum interface acceleration. Measurements are also compared to implosion data from 4-time-frame laser shadowgraphy. Improved resolution measurements on the laser shadowgraph system have been used to examine the liner interface early in the shot to examine surface perturbations resulting from ETI for various seeding conditions. Fourier analysis examines the growth rates of wavelength bands of these structures to examine the transition from ETI to MRT. This work was supported by the U.S. DoE through award DE-SC0012328. S.G. Patel is supported by Sandia National Labs. D.A. Yager is supported by NSF fellowship grant DGE 1256260.

  2. Sex differences in spatial navigation and perception in human adolescents and emerging adults

    PubMed Central

    Sneider, Jennifer Tropp; Hamilton, Derek A.; Cohen-Gilbert, Julia E.; Crowley, David J.; Rosso, Isabelle M.; Silveri, Marisa M.

    2014-01-01

    Males typically outperform females on spatial tasks, beginning early in life and continuing into adulthood. This study aimed to characterize age and sex differences in human spatial ability using a virtual Water Maze Task (vWMT), which is based on the classic Morris water maze spatial navigation task used in rodents. Performance on the vWMT and on a task assessing visuospatial perception, Mental Rotations Test (MRT), was examined in 33 adolescents and 39 emerging adults. For the vWMT, significant effects of age and sex were observed for path length in the target region (narrower spatial sampling), and heading error, with emerging adults performing better than adolescents, and an overall male advantage. For the MRT, males scored higher than females, but only in emerging adulthood. Overall, sex differences in visuospatial perception (MRT) emerge differently from those observed on a classic navigation task, with age and sex-specific superior vWMT performance likely related to the use of more efficient strategies. Importantly, these results extend the developmental timeline of spatial ability characterization to include adolescent males and females performing a virtual version of the classic vWMT. PMID:25464337

  3. Simulations of parallel and transverse remanences in textured nano-patterned thin film media

    NASA Astrophysics Data System (ADS)

    El-Hilo, M.

    2010-05-01

    In this work the effects of dipolar coupling on the distribution of effective orientations in textured nano-patterned media is simulated. The modelled films consist of 50×50 cobalt grains of uniform diameters ( D=20 nm) arranged in hexagonal (triangular) arrays. The grains easy axes are distributed according to a Gaussian texture function with a standard deviation of 30° about the texture direction. For different array separations ( d), the distribution of anisotropy orientations is extracted from the simulated parallel Mrp( β) and transverse Mrt( β) remanence curves where β is the angle by which the film is rotated. For the non-interacting case, predictions show that, Mrt( β)=d Mrp( β)/d β which is consistent with Shrikman and Treves theory whereas for the interacting case, Mrt( β) is deviated from d Mrp( β)/d β. The extracted distribution of effective orientations is found to become narrower as the array separation is decreased which is due to dipolar-induced texturing effects.

  4. Conceptualization and validation of an open-source closed-loop deep brain stimulation system in rat

    PubMed Central

    Wu, Hemmings; Ghekiere, Hartwin; Beeckmans, Dorien; Tambuyzer, Tim; van Kuyck, Kris; Aerts, Jean-Marie; Nuttin, Bart

    2015-01-01

    Conventional deep brain stimulation (DBS) applies constant electrical stimulation to specific brain regions to treat neurological disorders. Closed-loop DBS with real-time feedback is gaining attention in recent years, after proved more effective than conventional DBS in terms of pathological symptom control clinically. Here we demonstrate the conceptualization and validation of a closed-loop DBS system using open-source hardware. We used hippocampal theta oscillations as system input, and electrical stimulation in the mesencephalic reticular formation (mRt) as controller output. It is well documented that hippocampal theta oscillations are highly related to locomotion, while electrical stimulation in the mRt induces freezing. We used an Arduino open-source microcontroller between input and output sources. This allowed us to use hippocampal local field potentials (LFPs) to steer electrical stimulation in the mRt. Our results showed that closed-loop DBS significantly suppressed locomotion compared to no stimulation, and required on average only 56% of the stimulation used in open-loop DBS to reach similar effects. The main advantages of open-source hardware include wide selection and availability, high customizability, and affordability. Our open-source closed-loop DBS system is effective, and warrants further research using open-source hardware for closed-loop neuromodulation. PMID:25897892

  5. Media multitasking and behavioral measures of sustained attention.

    PubMed

    Ralph, Brandon C W; Thomson, David R; Seli, Paul; Carriere, Jonathan S A; Smilek, Daniel

    2015-02-01

    In a series of four studies, self-reported media multitasking (using the media multitasking index; MMI) and general sustained-attention ability, through performance on three sustained-attention tasks: the metronome response task (MRT), the sustained-attention-to-response task (SART), and a vigilance task (here, a modified version of the SART). In Study 1, we found that higher reports of media multitasking were associated with increased response variability (i.e., poor performance) on the MRT. However, in Study 2, no association between reported media multitasking and performance on the SART was observed. These findings were replicated in Studies 3a and 3b, in which we again assessed the relation between media multitasking and performance on both the MRT and SART in two large online samples. Finally, in Study 4, using a large online sample, we tested whether media multitasking was associated with performance on a vigilance task. Although standard vigilance decrements were observed in both sensitivity (A') and response times, media multitasking was not associated with the size of these decrements, nor was media multitasking associated with overall performance, in terms of either sensitivity or response times. Taken together, the results of the studies reported here failed to demonstrate a relation between habitual engagement in media multitasking in everyday life and a general deficit in sustained-attention processes. PMID:25280520

  6. Increased Systemic Exposure of Methotrexate by a Polyphenol-Rich Herb via Modulation on Efflux Transporters Multidrug Resistance-Associated Protein 2 and Breast Cancer Resistance Protein.

    PubMed

    Yu, Chung-Ping; Hsieh, Yun-Chung; Shia, Chi-Sheng; Hsu, Pei-Wen; Chen, Jen-Yuan; Hou, Yu-Chi; Hsieh, Yo-Wen

    2016-01-01

    Scutellariae radix (SR, roots of Scutellaria baicalensis Georgi), a popular Chinese medicine, contains plenty of flavonoids such as baicalin, wogonoside, baicalein, and wogonin. Methotrexate (MTX), an important immunosuppressant with a narrow therapeutic index, is a substrate of multidrug resistance-associated proteins (MRPs) and breast cancer resistance protein (BCRP). This study investigated the effect of SR on MTX pharmacokinetics and the underlying mechanisms. Rats were orally administered MTX alone and with 1.0 or 2.0 g/kg of SR. The serum concentrations of MTX were determined by a fluorescence polarization immunoassay. Cell models were used to explore the involvement of MRP2 and BCRP in the interaction. The results showed that 1.0 g/kg of SR significantly increased Cmax, AUC(0-30), AUC(0-2880), and mean residence time (MRT) of MTX by 50%, 45%, 501%, and 347%, respectively, and 2.0 g/kg of SR significantly enhanced the AUC(0-2880) and MRT by 242% and 293%, respectively, but decreased AUC(0-30) by 41%. Cell line studies indicated that SR activated the BCRP-mediated efflux transport, whereas the serum metabolites of SR inhibited both the BCRP- and MRP2-mediated efflux transports. In conclusion, SR ingestion increased the systemic exposure and MRT of MTX via modulation on MRP2 and BCRP. PMID:26852865

  7. Plasma superwarfarin levels and vitamin K1 treatment in dogs with anticoagulant rodenticide poisoning.

    PubMed

    Robben, J H; Kuijpers, E A; Mout, H C

    1998-01-01

    The plasma concentration, plasma half-life (t1/2), and mean residence time (MRT) of rodenticide anticoagulants were determined in 21 dogs in which a preliminary diagnosis of anticoagulant rodenticide poisoning had been made. Brodifacoum, difethialone, and difenacoum were detected by high-performance liquid chromatography (HPLC) in the plasma of 13, 3, and 2 dogs, respectively. At presentation the plasma concentration ranged from below the detection limit (10 ng/L) to 851 ng/L. Toxin could not be detected in 3 dogs, despite these animals showing characteristic coagulation disturbances and a positive response to therapy with vitamin K1. In 7 dogs the estimated t1/2 of brodifacoum ranged from 0.9 to 4.7 (median 2.4) days with a MRT of 1.9 to 3.7 (median 2.8) days. In 2 dogs the individual t1/2 of difethialone was 2.2 and 3.2 days and the MRT was 2.3 and 2.8 days, respectively. Two dogs died during emergency treatment. Treatment in the remaining 19 dogs consisted of the administration of vitamin K1 and supportive therapy. The dose of vitamin K1 was reduced in a stepwise manner as long as the prothrombin time remained within physiological limits. The variation in initial plasma concentrations of the anticoagulants combined with the results of treatment support the idea that an individual therapeutic approach is warranted. PMID:9477532

  8. Nonequilibrium scheme for computing the flux of the convection-diffusion equation in the framework of the lattice Boltzmann method.

    PubMed

    Chai, Zhenhua; Zhao, T S

    2014-07-01

    In this paper, we propose a local nonequilibrium scheme for computing the flux of the convection-diffusion equation with a source term in the framework of the multiple-relaxation-time (MRT) lattice Boltzmann method (LBM). Both the Chapman-Enskog analysis and the numerical results show that, at the diffusive scaling, the present nonequilibrium scheme has a second-order convergence rate in space. A comparison between the nonequilibrium scheme and the conventional second-order central-difference scheme indicates that, although both schemes have a second-order convergence rate in space, the present nonequilibrium scheme is more accurate than the central-difference scheme. In addition, the flux computation rendered by the present scheme also preserves the parallel computation feature of the LBM, making the scheme more efficient than conventional finite-difference schemes in the study of large-scale problems. Finally, a comparison between the single-relaxation-time model and the MRT model is also conducted, and the results show that the MRT model is more accurate than the single-relaxation-time model, both in solving the convection-diffusion equation and in computing the flux.

  9. The Morehead Radio Telescope: Design and Fabrication of a Research Instrument for Undergraduate Faculty and Student Research in Radio Frequency Astrophysics

    NASA Astrophysics Data System (ADS)

    Malphrus, B. K.

    1996-12-01

    Faculty and students of the Departments of Physical Sciences and Industrial Education and Technology at Morehead State University have designed and assembled the Morehead Radio Telescope (MRT) to provide a research instrument for undergraduate astronomy and physics students and an active laboratory for physics, engineering, and computer science undergraduates and faculty. The instrument will function as a research and educational instrument for undergraduate students, faculty, and science teachers throughout Kentucky. The goals of the MRT program are to enhance the curricula in physics, physical science, electronics, and science education programs by serving to provide: 1.) a research instrument for investigations in astronomy and astrophysics; 2.) an active laboratory in astronomy, physics, electrical engineering, and computer science; and 3.) a research instrument and laboratory for science teacher education and inservice programs. The MRT utilizes a 40-foot parabolic reflector, a low-noise hydrogen line receiver and a fully- automated alt-azimuth positioning system. The telescope incorporates a modular design in which components may be easily removed for use in laboratory investigations and for student research and design projects. The performance characteristics of the telescope allow a varied and in-depth scientific program. The sensitivity and versatility of the telescope design facilitate the investigation of a wide variety of astrophysically interesting phenomena.

  10. Revealing the underlying mechanism of microbeam radiation therapy with low energy Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    McNamara, A. L.; Oelfke, U.; Kuncic, Z.

    2014-03-01

    Microbeam radiation therapy (MRT) is a new experimental oncological modality, intended for the treatment of inoperable brain tumours, particularly in difficult cases where conventional radiation therapy can cause irreversible damage. MRT consists of an array of highly collimated, quasi-parallel x-ray microbeams aimed at the tumour tissue, delivering high dose within the beam path and low doses in regions between the beams. For reasons still not fully understood, healthy tissue exposed to the microbeam array is able to regenerate while tumour volumes are significantly reduced. Low energy Monte Carlo radiative transport simulations provide new insight into understanding the underlying mechanisms of MRT. In particular, predicting the ionisation cluster distribution, which is a significant cause of lethal damage to cells, would provide insight into the biological responses. Geant4-DNA was used to model an x-ray microbeam of width 20 μm in liquid water. Secondary electrons, predominately responsible for ionisation clustering, were tracked to predict damage to cells within and adjacent to the beams. We find that higher energy beams (100 keV) produce less secondary electrons in the regions outside the beam than low energy beams (30-50 keV).

  11. The Clinical Trials Program at the ESRF Biomedical Beamline ID17: Status and Remaining Steps

    SciTech Connect

    Requardt, H.; Bravin, A.; Prezado, Y.; Braeuer-Krisch, E.; Renier, M.; Brochard, Th.; Berkvens, P.; Nemoz, C.; Berruyer, G.; Esteve, F.; Elleaume, H.; Adam, J.-F.; Blattmann, H.; Laissue, J. A.; Kaser-Hotz, B.

    2010-06-23

    For several years the ID17 Biomedical beamline at the ESRF has developed synchrotron radiation therapy preclinical programmes to treat aggressive brain tumours. Two techniques have been developed at the ESRF:a) The Microbeam Radiation Therapy (MRT) using spatially fractionated 'white beam' (energies 50-300 keV) irradiation (beam widths 25-100 {mu}m, spacing between beams 200-400 {mu}m ) with extremely high dose rates (up to about 20 kGy/s) and depositing very high doses (300-1000 Gy) in the targeted tissue.b) The Stereotactic Synchrotron Radiation Therapy (SSRT) using spatially homogeneous monochromatic beam with the energy closely above that of the K-edge of a contrast- or chemotherapeutical agent (iodine, gadolinium, platinum) loaded into the tumour volume for obtaining a dose-enhancement. In 2005 an International review panel of oncology experts has recommended to move to clinical trials on humans in SSRT and on large animals in MRT. The works required for this program were launched in autumn 2007 with constructing a new, dedicated experimental hutch for MRT and a major upgrade of the existing sample-positioning station to a patient-positioning station for SSRT. In parallel, safety systems are developed and progressively implemented and a patient treatment-planning system developed.

  12. Instability growth for magnetized liner inertial fusion seeded by electro-thermal, electro-choric, and material strength effects

    SciTech Connect

    Pecover, J. D.; Chittenden, J. P.

    2015-10-15

    A critical limitation of magnetically imploded systems such as magnetized liner inertial fusion (MagLIF) [Slutz et al., Phys. Plasmas 17, 056303 (2010)] is the magneto-Rayleigh-Taylor (MRT) instability which primarily disrupts the outer surface of the liner. MagLIF-relevant experiments have showed large amplitude multi-mode MRT instability growth growing from surface roughness [McBride et al., Phys. Rev. Lett. 109, 135004 (2012)], which is only reproduced by 3D simulations using our MHD code Gorgon when an artificially azimuthally correlated initialisation is added. We have shown that the missing azimuthal correlation could be provided by a combination of the electro-thermal instability (ETI) and an “electro-choric” instability (ECI); describing, respectively, the tendency of current to correlate azimuthally early in time due to temperature dependent Ohmic heating; and an amplification of the ETI driven by density dependent resistivity around vapourisation. We developed and implemented a material strength model in Gorgon to improve simulation of the solid phase of liner implosions which, when applied to simulations exhibiting the ETI and ECI, gave a significant increase in wavelength and amplitude. Full circumference simulations of the MRT instability provided a significant improvement on previous randomly initialised results and approached agreement with experiment.

  13. Virtual reality adaptive stimulation of limbic networks in the mental readiness training.

    PubMed

    Cosić, Kresimir; Popović, Sinisa; Kostović, Ivica; Judas, Milos

    2010-01-01

    A significant proportion of severe psychological problems in recent large-scale peacekeeping operations underscores the importance of effective methods for strengthening the stress resilience. Virtual reality (VR) adaptive stimulation, based on the estimation of the participant's emotional state from physiological signals, may enhance the mental readiness training (MRT). Understanding neurobiological mechanisms by which the MRT based on VR adaptive stimulation can affect the resilience to stress is important for practical application in the stress resilience management. After the delivery of a traumatic audio-visual stimulus in the VR, the cascade of events occurs in the brain, which evokes various physiological manifestations. In addition to the "limbic" emotional and visceral brain circuitry, other large-scale sensory, cognitive, and memory brain networks participate with less known impact in this physiological response. The MRT based on VR adaptive stimulation may strengthen the stress resilience through targeted brain-body interactions. Integrated interdisciplinary efforts, which would integrate the brain imaging and the proposed approach, may contribute to clarifying the neurobiological foundation of the resilience to stress. PMID:20543262

  14. Increased Systemic Exposure of Methotrexate by a Polyphenol-Rich Herb via Modulation on Efflux Transporters Multidrug Resistance-Associated Protein 2 and Breast Cancer Resistance Protein.

    PubMed

    Yu, Chung-Ping; Hsieh, Yun-Chung; Shia, Chi-Sheng; Hsu, Pei-Wen; Chen, Jen-Yuan; Hou, Yu-Chi; Hsieh, Yo-Wen

    2016-01-01

    Scutellariae radix (SR, roots of Scutellaria baicalensis Georgi), a popular Chinese medicine, contains plenty of flavonoids such as baicalin, wogonoside, baicalein, and wogonin. Methotrexate (MTX), an important immunosuppressant with a narrow therapeutic index, is a substrate of multidrug resistance-associated proteins (MRPs) and breast cancer resistance protein (BCRP). This study investigated the effect of SR on MTX pharmacokinetics and the underlying mechanisms. Rats were orally administered MTX alone and with 1.0 or 2.0 g/kg of SR. The serum concentrations of MTX were determined by a fluorescence polarization immunoassay. Cell models were used to explore the involvement of MRP2 and BCRP in the interaction. The results showed that 1.0 g/kg of SR significantly increased Cmax, AUC(0-30), AUC(0-2880), and mean residence time (MRT) of MTX by 50%, 45%, 501%, and 347%, respectively, and 2.0 g/kg of SR significantly enhanced the AUC(0-2880) and MRT by 242% and 293%, respectively, but decreased AUC(0-30) by 41%. Cell line studies indicated that SR activated the BCRP-mediated efflux transport, whereas the serum metabolites of SR inhibited both the BCRP- and MRP2-mediated efflux transports. In conclusion, SR ingestion increased the systemic exposure and MRT of MTX via modulation on MRP2 and BCRP.

  15. You Should Be the Specialist! Weak Mental Rotation Performance in Aviation Security Screeners - Reduced Performance Level in Aviation Security with No Gender Effect.

    PubMed

    Krüger, Jenny K; Suchan, Boris

    2016-01-01

    Aviation security screeners analyze a large number of X-ray images per day and seem to be experts in mentally rotating diverse kinds of visual objects. A robust gender-effect that men outperform women in the Vandenberg & Kuse mental rotation task has been well documented over the last years. In addition it has been shown that training can positively influence the overall task-performance. Considering this, the aim of the present study was to investigate whether security screeners show better performance in the Mental Rotation Test (MRT) independently of gender. Forty-seven security screeners of both sexes from two German airports were examined with a computer based MRT. Their performance was compared to a large sample of control subjects. The well-known gender-effect favoring men on mental rotation was significant within the control group. However, the security screeners did not show any sex differences suggesting an effect of training and professional performance. Surprisingly this specialized group showed a lower level of overall MRT performance than the control participants. Possible aviation related influences such as secondary effects of work-shift or expertise which can cumulatively cause this result are discussed.

  16. Media multitasking and behavioral measures of sustained attention.

    PubMed

    Ralph, Brandon C W; Thomson, David R; Seli, Paul; Carriere, Jonathan S A; Smilek, Daniel

    2015-02-01

    In a series of four studies, self-reported media multitasking (using the media multitasking index; MMI) and general sustained-attention ability, through performance on three sustained-attention tasks: the metronome response task (MRT), the sustained-attention-to-response task (SART), and a vigilance task (here, a modified version of the SART). In Study 1, we found that higher reports of media multitasking were associated with increased response variability (i.e., poor performance) on the MRT. However, in Study 2, no association between reported media multitasking and performance on the SART was observed. These findings were replicated in Studies 3a and 3b, in which we again assessed the relation between media multitasking and performance on both the MRT and SART in two large online samples. Finally, in Study 4, using a large online sample, we tested whether media multitasking was associated with performance on a vigilance task. Although standard vigilance decrements were observed in both sensitivity (A') and response times, media multitasking was not associated with the size of these decrements, nor was media multitasking associated with overall performance, in terms of either sensitivity or response times. Taken together, the results of the studies reported here failed to demonstrate a relation between habitual engagement in media multitasking in everyday life and a general deficit in sustained-attention processes.

  17. Residence time distribution in a large unconfined-semiconfined aquifer in the Argentine Pampas using 3H/3He and CFC tracers

    NASA Astrophysics Data System (ADS)

    Martínez, D. E.; Fourré, E.; Londoño, O. M. Quiroz; Jean-Baptiste, P.; Galli, M. Glok; Dapoigny, A.; Grondona, S. I.

    2016-08-01

    The Pampa region in Argentina includes vast unconfined-semiconfined aquifers that local economies depend upon, but detailed knowledge of the associated water resources is still lacking. The Pampeano aquifer in the Pampa plain of Argentina covers around 1.5 million km2. In order to achieve a better understanding of the hydrogeological system through the estimation of mean residence times (MRT), water samples were taken from 12 monitoring wells, drilled at different depths in four locations, and analyzed for environmental tracers. The concentrations of 3H, tritiogenic 3He and chlorofluorocarbons (CFCs) can be explained by mixtures of young waters adjusted to exponential piston flow models (EPM) or dispersion models (DM), and different proportions of tracer-free waters (dead water). The sampling site located very close to the water divide shows a dominance of young waters: 85 % of water best represented by a DM model with a MRT of 3 years. For the shallow wells at other sites, best-fitting models result in a DM with MRT between 20 and 35 years, and proportions of dead water between 40 and 60 %. These results lead to important updates in the conceptual model of the Pampeano aquifer. Large proportions of dead water at a few meters depth can be the consequence of upward flows in a multilayered aquifer or diffusive retardation in the inter-bedded clay layers.

  18. Sex differences in spatial navigation and perception in human adolescents and emerging adults.

    PubMed

    Sneider, Jennifer T; Hamilton, Derek A; Cohen-Gilbert, Julia E; Crowley, David J; Rosso, Isabelle M; Silveri, Marisa M

    2015-02-01

    Males typically outperform females on spatial tasks, beginning early in life and continuing into adulthood. This study aimed to characterize age and sex differences in human spatial ability using a virtual Water Maze Task (vWMT), which is based on the classic Morris water maze spatial navigation task used in rodents. Performance on the vWMT and on a task assessing visuospatial perception, Mental Rotations Test (MRT), was examined in 33 adolescents and 39 emerging adults. For the vWMT, significant effects of age and sex were observed for path length in the target region (narrower spatial sampling), and heading error, with emerging adults performing better than adolescents, and an overall male advantage. For the MRT, males scored higher than females, but only in emerging adulthood. Overall, sex differences in visuospatial perception (MRT) emerge differently from those observed on a classic navigation task, with age and sex-specific superior vWMT performance likely related to the use of more efficient strategies. Importantly, these results extend the developmental timeline of spatial ability characterization to include adolescent males and females performing a virtual version of the classic vWMT. PMID:25464337

  19. A lattice-Boltzmann scheme of the Navier-Stokes equations on a 3D cuboid lattice

    NASA Astrophysics Data System (ADS)

    Min, Haoda; Peng, Cheng; Wang, Lian-Ping

    2015-11-01

    The standard lattice-Boltzmann method (LBM) for fluid flow simulation is based on a square (in 2D) or cubic (in 3D) lattice grids. Recently, two new lattice Boltzmann schemes have been developed on a 2D rectangular grid using the MRT (multiple-relaxation-time) collision model, by adding a free parameter in the definition of moments or by extending the equilibrium moments. Here we developed a lattice Boltzmann model on 3D cuboid lattice, namely, a lattice grid with different grid lengths in different spatial directions. We designed our MRT-LBM model by matching the moment equations from the Chapman-Enskog expansion with the Navier-Stokes equations. The model guarantees correct hydrodynamics. A second-order term is added to the equilibrium moments in order to restore the isotropy of viscosity on a cuboid lattice. The form and the coefficients of the extended equilibrium moments are determined through an inverse design process. An additional benefit of the model is that the viscosity can be adjusted independent of the stress-moment relaxation parameter, thus improving the numerical stability of the model. The resulting cuboid MRT-LBM model is then validated through benchmark simulations using laminar channel flow, turbulent channel flow, and the 3D Taylor-Green vortex flow.

  20. Absorption enhancement of rectally infused cefoxitin by medium chain monoglycerides in conscious rats.

    PubMed

    Watanabe, Y; van Hoogdalem, E J; de Boer, A G; Breimer, D D

    1988-10-01

    The enhancing effect of the medium chain monoglycerides glyceryl-1-monoctanoate (GMO), glyceryl-1-monodecanoate (GMD), and glyceryl-1-monododecanoate (GMDD) on rectal absorption of the cephalosporin antibiotic cefoxitin [(6R,7S)-3-hydroxymethyl)-7-methoxy-8-oxo-7-[2-(2-thienyl)acetamido]-5- thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid carbamate (ester)] was investigated in unanesthetized rats. Rectal infusion of 3 mg of cefoxitin sodium without monoglyceride resulted in a mean bioavailability of 31 +/- 18% and a mean residence time (MRT) of 134 +/- 44 min. Coadministration with 53% (w/w) GMO significantly enhanced cefoxitin absorption, resulting in a mean bioavailability of 84 +/- 11% and a mean MRT of 75 +/- 8 min. In a lower concentration, GMD (13% w/w) also significantly promoted cefoxitin bioavailability to 68 +/- 14% and reduced MRT to 70 +/- 11 min. With GMDD only, a trend of increasing bioavailability with increasing monoglyceride concentration was observed, which may be explained by its limited aqueous solubility. Concerning the action of GMO and GMD, the longer monoglyceride is, in terms of effective concentration, more potent in enhancing the extent and rate of cefoxitin absorption. However, a further increase in chain length results in a loss of effect, indicating that the effect of monoglycerides on drug absorption may be determined by their intrinsic absorption enhancing action and solubility.

  1. Ein Framework für echtzeitfähige Ethernet-Netzwerke

    NASA Astrophysics Data System (ADS)

    Dopatka, Frank

    Im Rahmen dieser Arbeit wird die Entwicklung eines formalen Framewoks vorgestellt, mit dessen Hilfe zwischen der Kompatibilität zum verbreiteten baumförmigen Standard-Ethernet und der Einhaltung von Echtzeitanforderungen einer automatisierten Anlage variiert werden kann. Damit kann bereits vor der Auswahl einer bestimmten Technologie eine Schedule der Echtzeit-Übertragungen offline kalkuliert und simuliert werden, sobald die Anforderungen der Geräte im industriellen Echtzeit-Netzwerk bekannt sind.

  2. [Association of peer victimization, coping, and pathological internet use among adolescents].

    PubMed

    Strittmatter, Esther; Brunner, Romuald; Fischer, Gloria; Parzer, Peter; Resch, Franz; Kaess, Michael

    2014-03-01

    Fragestellung: In der vorliegenden Studie wurde untersucht, ob ein Zusammenhang zwischen pathologischem Internetgebrauch, Mobbing und Copingstilen bei Jugendlichen mit Mobbingerfahrungen besteht. Methodik: Im Rahmen einer europäischen schulbasierten Studie (SEYLE) wurde eine repräsentative Querschnittsuntersuchung an 1357 Schülern aus Heidelberg und Umgebung durchgeführt (710 weibliche/647 männlich Jugendliche; mittleres Alter 14.7; SD 0.8). Pathologischer Internetgebrauch wurde mit dem Young Diagnostic Questionnaire erhoben. Mobbing wurde in verbales, körperliches Mobbing und Mobbing in der Beziehung unterteilt. Hinsichtlich der Copingstile wurden aktives Coping, Vermeidung, Hilfe suchen und sonstige Strategien unterschieden. Als Kovariate wurde die psychische Symptombelastung mittels Strengths and Difficulties Questionnaire erfasst. Ergebnisse: 4.8 % der Schüler wiesen einen pathologischen Internetgebrauch auf, 14.4 % zeigten einen problematischen Internetgebrauch. Insgesamt berichteten 52.3 % der Jugendlichen über Erfahrungen mit Mobbing (38.7 % verbales Mobbing, 19.8 % körperliches Mobbing, 34.1 % Mobbing in der Beziehung). Es bestand ein signifikanter Zusammenhang von Mobbingerfahrungen und pathologischem Internetgebrauch, der zum Teil durch die psychische Symptombelastung erklärt werden konnte. Hinsichtlich der Copingstile bei stattgefundenem Mobbing bestand kein signifikanter Unterschied zwischen Schülern mit normalem, problematischem und pathologischem Internetgebrauch. Schlussfolgerungen: Aufgrund des Zusammenhanges zwischen Mobbing, psychischer Symptombelastung und pathologischem Internetgebrauch sind in der Zukunft schulbasierte sowie familienbezogene Präventionsmaßnahmen und evaluierte Therapieprogramme erforderlich.

  3. The development and characterization of a first generation carbon nanotube x-ray based microbeam radiation therapy system

    NASA Astrophysics Data System (ADS)

    Hadsell, Michael John, Jr.

    Microbeam radiation therapy (MRT) is a new type of cancer treatment currently being studied at scattered synchrotron sites throughout the world. It has been shown to be capable of ablating aggressive brain tumors in rats while almost completely sparing the surrounding normal tissue. This promising technique has yet to find its way to the clinic, however, because the radiobiological mechanisms behind its efficacy are still largely unknown. This is partly due to the lack of a compact device that could facilitate more large scale research. The challenges inherent to creating a compact device lie within the structure of MRT, which uses parallel arrays of ultra high-dose, orthovoltage, microplanar beams on the order of 100mum thick and separated by four to ten times their width. Because of focal spot limitations, current commercial orthovoltage devices are simply not capable of creating such arrays at dose rates high enough for effective treatment while maintaining the microbeam pattern necessary to retain the high therapeutic ratio of the technique. Therefore, the development of a compact MRT device using carbon nanotube (CNT) cathode based X-ray technology is presented here. CNT cathodes have been shown to be capable of creating novel focal spot arrays on a single anode while being robust enough for long-term use in X-ray tubes. Using these cathodes, an X-ray tube with a single focal line has been created for the delivery of MRT dose distributions in radiobiological studies on small animals. In this work, the development process and final design of this specialized device will be detailed, along with the optimization and stabilization of its use for small animal studies. In addition, a detailed characterization of its final capabilities will be given; including a comprehensive measurement of its X-ray focal line dimensions, a description and evaluation of its collimator alignment and microbeam dimensions, and a full-scale phantom-based quantification of its dosimetric

  4. Intra and interindividual variability in the kinetics of a poorly and highly metabolising solvent.

    PubMed Central

    Opdam, J J

    1989-01-01

    Human subjects were experimentally exposed three times simultaneously to tetrachloroethene (PER) and trichloroethene (TRI) under conditions of rest and exercise. In each subject the individual kinetics for both PER and TRI were determined three times by means of frequent sampling of alveolar air up to 70-500 and 20-310 hours respectively. For PER the following parameters were found: the weighted pulmonary clearance (Clpul) = 0.27-0.64 l/min, terminal half time (t1/2(z] = 54-250 hours, mean residence time (MRT) = 35-155 hours, and volume of distribution (Vdss) = 1100-3570 1. For TRI the apparent hepatic clearance (CLhep) = 0.5-1.7 l/min, weighted Clpul = 0.41-1.48 l/min, t1/2(z) = 13-55 hours, MRT = 2.3-22 hours, and the Vdss = 420-3100 1. The intra and intersubject variation in the kinetics were reflected in the predictions of the individual time course of the solvent in the blood at repeated exposure up to five weeks (eight hours a day, five days a week). For PER the intrasubject variation in the predicted concentrations on the Monday mornings was within 5-15% whereas the intersubject variation was about twofold. For TRI the intrasubject variation in the predicted morning concentrations was substantial (two to threefold), whereas the intersubject variation was about 10-fold. The intrasubject variation was probably caused mainly by the level of exercise during exposure. The Clhep was not greatly influenced by the level of exercise, whereas exercise during exposure increased the MRT. Exercise during exposure probably speeds up the process of distribution and, therefore, there is a lower concentration in the blood relative to the increased respiratory intake. As a consequence, despite the increased Clpul and the rather unchanged Clhep, pulmonary and metabolic excretion will be delayed and the MRT increased. The MRT is more suited to predict the individual cumulation of both PER and TRI than the terminal t1/2(z). PMID:2611156

  5. A review of current research in microwave resonance therapy: novel opportunities in medical treatment.

    PubMed

    Jovanović-Ignjatić, Z; Raković, D

    1999-01-01

    Microwave Resonance Therapy (MRT) is a novel medical treatment, which represents a synthesis of the ancient Chinese traditional knowledge in medicine (acupuncture) and recent breakthroughs in biophysics. By affecting the appropriate acupuncture points by the generation of high frequency microwaves (52-78 GHz), remarkable clinical results are being achieved in surgery, orthopedic and traumatology, cardiovascular disorders, urology, gynecology, dermatology, gastroenterology, pulmology, upper respiratory tract, cardiology, neurology, and oncology during the last decade--the MRT being contraindicated only in the cases of acute pain in the abdomen demanding an operation, pregnancy, and menstruation cycle. In this paper the quantum-like macroscopic biophysical basis of the MRT and its technical details are elaborated too, offering a new insight in the mechanisms of the assembling gap junction hemichannels upon the internal microwave (MW) electromagnetic field spatio-temporal maximums at the temporary position of the acupuncture system, and, hence, the very biophysical nature of the temporary psychosomatic health or disease. The quantum-like coherent characteristics of the MRT (sharply-resonant sensory response of the disordered organism, extremely low-intensity and low-energy non-thermal biologically efficient MW radiation, and negligible MW energy losses down acupuncture meridians) might be viewed as a consequence of the existence of biological nonlocal selfconsistent macroscopic quantum potentials, which can give rise to nonlinear coherent EM MW long-range maser-like excitations of biological nonlinear absorption medium with the cells as active centers--with acupuncture meridians related to eigenfrequencies and spatio-temporal eigenwaves distributions of every individual biological quantum system. This suggests that a healthy condition might be considered as an absolute minimum (ground state) of the nonlocal selfconsistent macroscopic quantum potential of the organism

  6. The Influence of Ball Velocity and Court Illumination on Reaction Time for Tennis Volley

    PubMed Central

    Tu, Jui-hung; Lin, Yaw-feng; Chin, Shu-chen

    2010-01-01

    The he purpose of this study is to examine the effects of ball velocity, court illumination, and volley type on the reaction time (RT) of a tennis athlete for a volley stroke. Eights cases with two different ball velocities (high and low), two volley types (forehand and backhand ) and two court illumination levels (dark and bright) were studied. The 30 participating subjects consisted of 18 male and 12 female college tennis athletes (age: 24 ± 3.2 yr), with a United States Tennis Association (USTA) ranking above 2.5. In order to ensure the validity of real-world correlations, the experiments were designed to simulate real competition situations. Reaction times were measured for volley strokes in response to different approaching ball velocities (high: 25.05 ± 0.37 m/s and low: 17.56 ± 0.92 m·s-1) for several volley types (forehand and backhand) and court illumination levels (55649 ± 4292 lux and 363.24 ± 6.53 lux on the court). During the tests, the signals from an electromyogram sensor and a 3-axis accelerometer (± 50 g) were recorded using an NI DAQ card (NI PXI-6251) and then analyzed to determine reaction time (RT), premotor reaction time (PRT), and motor reaction time (MRT) through the LabVIEW system. Subsequent 3-way ANOVA analysis indicated no RT, PRT, or MRT interaction between ball velocity, volley type and illumination. The ball velocity and illumination parameters did affect RT and PRT values significantly with p < 0.05, no significant variation in MRT was observed across any implemented experimental conditions. All experimental results indicate that ball velocity and illumination levels strongly affect the value of PRT, but have no significant effect on the value of MRT, the changes in RT were dominated by PRT. Key points RT can generally be divided into two components with the help of the electromyogram (EMG) signal - the premotor reaction time (PRT) and the motor reaction time (MRT). The purpose of this study is to examine the effects of ball

  7. Effect of grass hay intake on fiber digestion and digesta retention time in the hindgut of horses.

    PubMed

    Miyaji, M; Ueda, K; Hata, H; Kondo, S

    2014-04-01

    Eight Thoroughbred horses were used to examine the effects of grass hay intake on the fiber digestion and the retention time of digesta in the total gastrointestinal tract and the hindgut segments. The horses were randomly assigned to 2 groups and offered 2.0 (high intake [HI]) or 1.3 kg DM/(100 kg BW • d; low intake [LI]) of timothy hay in equal amounts every 3 h for 17 d. The digestibility and total tract mean retention time of digesta (tMRT) in the total gastrointestinal tract were measured from d 11 to d 15. To measure the mean retention time of digesta in each hindgut segment (sMRT), the horses were euthanized on d 17, after being fed a series of hay markers that were labeled with different rare earth elements. The digesta were collected from the ileum, cecum, right ventral colon (RVC), left ventral colon (LVC), left dorsal colon, right dorsal colon (RDC), and small colon (SC) to measure fiber digestibility, sMRT, VFA concentration, and fibrolytic activities. The digestibility of NDF and ADF in the total gastrointestinal tract was lower (P < 0.01) for HI than for LI. The cumulative disappearance of NDF and ADF from the ileum to the LVC attained 90% of total tract digestion regardless of hay intake. Values did not differ according to treatments in the ileum and the cecum but were lower (P < 0.01) for HI than for LI in the postcecal segments. This was caused by the smaller increase in the cumulative NDF and ADF disappearance from the cecum to the RVC for HI than for LI. The solid phase tMRT was shorter (P = 0.04) for HI than for LI. Although sMRT in the RDC and SC were shorter (P = 0.04 and P < 0.01, respectively) for HI than for LI, no differences were observed in the other hindgut segments. There was no difference between treatments in the total VFA concentration, VFA proportions, or the specific activity of carboxymethyl cellulase and xylanase in each hindgut segment. The fibrolytic activity for the cecum and RVC were greatest and decreased beyond the LVC

  8. Experiences with Testing the Largest Ground System NASA Has Ever Built

    NASA Technical Reports Server (NTRS)

    Lehtonen, Ken; Messerly, Robert

    2003-01-01

    In the 1980s, the National Aeronautics and Space Administration (NASA) embarked upon a major Earth-focused program called Mission to Planet Earth. The Goddard Space Flight Center (GSFC) was selected to manage and develop a key component - the Earth Observing System (EOS). The EOS consisted of four major missions designed to monitor the Earth. The missions included 4 spacecraft. Terra (launched December 1999), Aqua (launched May 2002), ICESat (Ice, Cloud, and Land Elevation Satellite, launched January 2003), and Aura (scheduled for launch January 2004). The purpose of these missions was to provide support for NASA s long-term research effort for determining how human-induced and natural changes affect our global environment. The EOS Data and Information System (EOSDIS), a globally distributed, large-scale scientific system, was built to support EOS. Its primary function is to capture, collect, process, and distribute the most voluminous set of remotely sensed scientific data to date estimated to be 350 Gbytes per day. The EOSDIS is composed of a diverse set of elements with functional capabilities that require the implementation of a complex set of computers, high-speed networks, mission-unique equipment, and associated Information Technology (IT) software along with mission-specific software. All missions are constrained by schedule, budget, and staffing resources, and rigorous testing has been shown to be critical to the success of each mission. This paper addresses the challenges associated with the planning, test definition. resource scheduling, execution, and discrepancy reporting involved in the mission readiness testing of a ground system on the scale of EOSDIS. The size and complexity of the mission systems supporting the Aqua flight operations, for example, combined with the limited resources available, prompted the project to challenge the prevailing testing culture. The resulting success of the Aqua Mission Readiness Testing (MRT) program was due in no

  9. Sugars in soil: Review of sources, contents, fate and functions

    NASA Astrophysics Data System (ADS)

    Gunina, Anna; Kuzyakov, Yakov

    2015-04-01

    Sugars are the most abundant organic compounds in the biosphere because they are monomers of all polysaccharides. We summarized the results of the last 40 years on sources, content and fate of sugars in soil and discussed their main functions in soil. We especially focused on uptake and utilization of sugars by microorganisms as this is by far the dominating process of sugars transformation in soil. Two databases have been created and analyzed. The 1st database was focused on the contents of cellulose, non-cellulose, hot water and cold water extractable sugars in soils (348 data from 32 studies). This database was also used to determine the primary (plant derived) and secondary (microbially and soil organic matter (SOM) derived) sources of carbohydrates in soil. The galactose+mannose/arabinose+xylose (GM/AX) ratio was calculated to analyze the origin of sugars in soil. The 2nd database was focused on the fate of sugar C in soil (734 data pairs from 32 studies), and only the papers used 13C or 14C labelled sugars were included. All data to the fate were analyzed and presented in dynamics. This allowed to calculate: 1) maximal rate of glucose-C decomposition, 2) mean residence time (MRT) of C of the initially applied sugars, 3) MRT of glucose-C incorporated into microbial biomass (MB) and SOM pools. Content of hexoses was 3-4 times higher than that of pentoses for both cellulose and non-cellulose sugars, because hexoses have two sources in soil: plants and microorganisms. The GM/AX ratio revealed higher contribution of hexoses in forest (ratio was 1.5) than in cropland and grassland soils (ratio was 0.7-1), reflecting high input of hexoses with forest litter. The MRT of sugars in soil solution was much less than 30 minutes. Based on the experiments with 13C or 14C labelled glucose, the maximal rate of glucose C decomposition in microbial biomass was ˜ 1min-1. Considering this rate, the glucose input from plants and content of sugar C in soil, we estimated that only

  10. Threshold groundwater ages and young water fractions estimated from 3H, 3He, and 14C

    NASA Astrophysics Data System (ADS)

    Kirchner, James; Jasechko, Scott

    2016-04-01

    It is widely recognized that a water sample taken from a running stream is not described by a single age, but rather by a distribution of ages. It is less widely recognized that the same principle holds true for groundwaters, as indicated by the commonly observed discordances between model ages obtained from different tracers (e.g., 3H vs 14C) in the same sample. Water age distributions are often characterized by their mean residence times (MRT's). However, MRT estimates are highly uncertain because they depend on the shape of the assumed residence time distribution (in particular on the thickness of the long-time tail), which is difficult or impossible to constrain with data. Furthermore, because MRT's are typically nonlinear functions of age tracer concentrations, they are subject to aggregation bias. That is, MRT estimates derived from a mixture of waters with different ages (and thus different tracer concentrations) will systematically underestimate the mixture's true mean age. Here, building on recent work with stable isotope tracers in surface waters [1-3], we present a new framework for using 3H, 3He and 14C to characterize groundwater age distributions. Rather than describing groundwater age distributions by their MRT, we characterize them by the fraction of the distribution that is younger or older than a threshold age. The threshold age that separates "young" from "old" water depends on the characteristics of the specific tracer, including its history of atmospheric inputs. Our approach depends only on whether a given slice of the age distribution is younger or older than the threshold age, but not on how much younger or older it is. Thus our approach is insensitive to the tails of the age distribution, and is therefore relatively unaffected by uncertainty in the distribution's shape. Here we show that concentrations of 3H, 3He, and 14C are almost linearly related to the fractions of water that are younger or older than specified threshold ages. These

  11. THE INFLUENCE OF SUBMERGED MACROPHYTES ON SEDIMENTARY DIATOM ASSEMBLAGES(1).

    PubMed

    Vermaire, Jesse C; Prairie, Yves T; Gregory-Eaves, Irene

    2011-12-01

    Submerged macrophytes are a central component of lake ecosystems; however, little is known regarding their long-term response to environmental change. We have examined the potential of diatoms as indicators of past macrophyte biomass. We first sampled periphyton to determine whether habitat was a predictor of diatom assemblage. We then sampled 41 lakes in Quebec, Canada, to evaluate whether whole-lake submerged macrophyte biomass (BiomEpiV) influenced surface sediment diatom assemblages. A multivariate regression tree (MRT) was used to construct a semiquantitative model to reconstruct past macrophyte biomass. We determined that periphytic diatom assemblages on macrophytes were significantly different from those on wood and rocks (ANOSIM R = 0.63, P < 0.01). A redundancy analysis (RDA) of the 41-lake data set identified BiomEpiV as a significant (P < 0.05) variable in structuring sedimentary diatom assemblages. The MRT analysis classified the lakes into three groups. These groups were (A) high-macrophyte, nutrient-limited lakes (BiomEpiV ≥525 μg · L(-1) ; total phosphorus [TP] <35 μg · L(-1) ; 23 lakes); (B) low-macrophyte, nutrient-limited lakes (BiomEpiV <525 μg · L(-1) ; TP <35 μg · L(-1) ; 12 lakes); and (C) eutrophic lakes (TP ≥35 μg · L(-1) ; six lakes). A semiquantitative model correctly predicted the MRT group of the lake 71% of the time (P < 0.001). These results suggest that submerged macrophytes have a significant influence on diatom community structure and that sedimentary diatom assemblages can be used to infer past macrophyte abundance.

  12. Active thrusting within the Himalayan orogenic wedge in the Kashmir Himalayas

    NASA Astrophysics Data System (ADS)

    Gavillot, Y.

    2011-12-01

    Numerous lines of evidence indicate that significant distributed deformation occurs within the Himalayan fold-thrust belt. Active thrust faults lie as much as 100 km north of the active thrust front. Whereas geochemical and topographical data provide circumstantial evidence for internal deformation in Nepal, new mapping demonstrates that an active emergent thrust fault system extends stepwise from the Balakot-Bagh fault (source of the Mw 7.6 2005 Kashmir earthquake in Pakistan) more than 200 km to the southeast on the Riasi fault (RT). The RT with a fault length of ~70 km, is a ~50° northeast-dipping reverse fault system, which sits ~40 km north of the deformation front in the Kashmiri Himalaya of northwest India. Our mapping demonstrates that the Riasi thrust consists of two strands. The northern strand, Main Riasi thrust (MRT) strand, places Precambrian Sirban Limestone on folded unconsolidated (Pleistocene?) conglomerates. Undeformed younger alluvial deposits (Holocene?) overlyie the MRT, which implies no Holocene (?) surface rupture on this strand. To the south, the surface expression of the Riasi frontal thrust (RFT) includes a fault scarp and offset ~10 ka terrace deposits dated with 36CL depth profiles. OSL and 10Be depth profile dating indicate an age range between ~80 ka to ~30 ka for the Bidda terrace in the upper plate of the MRT, yielding estimates of long-term uplift rate of 5.0 ± 2.2 mm/yr, slip rate of 6.4 ± 2.9 mm/yr, and shortening rate of 4.1 ± 1.9mm/yr. Given a ~34 mm/yr India-Asia convergence rate in the NW Himalaya, our results indicate that internal deformation within the orogenic belt accounts for at least ~10% of the total India-Eurasia plate convergence, with remaining shortening absorbed mainly at the deformation front.

  13. SWI/SNF mediates polycomb eviction and epigenetic reprogramming of the INK4b-ARF-INK4a locus.

    PubMed

    Kia, Sima Kheradmand; Gorski, Marcin M; Giannakopoulos, Stavros; Verrijzer, C Peter

    2008-05-01

    Stable silencing of the INK4b-ARF-INK4a tumor suppressor locus occurs in a variety of human cancers, including malignant rhabdoid tumors (MRTs). MRTs are extremely aggressive cancers caused by the loss of the hSNF5 subunit of the SWI/SNF chromatin-remodeling complex. We found previously that, in MRT cells, hSNF5 is required for p16(INK4a) induction, mitotic checkpoint activation, and cellular senescence. Here, we investigated how the balance between Polycomb group (PcG) silencing and SWI/SNF activation affects epigenetic control of the INK4b-ARF-INK4a locus in MRT cells. hSNF5 reexpression in MRT cells caused SWI/SNF recruitment and activation of p15(INK4b) and p16(INK4a), but not of p14(ARF). Gene activation by hSNF5 is strictly dependent on the SWI/SNF motor subunit BRG1. SWI/SNF mediates eviction of the PRC1 and PRC2 PcG silencers and extensive chromatin reprogramming. Concomitant with PcG complex removal, the mixed lineage leukemia 1 (MLL1) protein is recruited and active histone marks supplant repressive ones. Strikingly, loss of PcG complexes is accompanied by DNA methyltransferase DNMT3B dissociation and reduced DNA methylation. Thus, various chromatin states can be modulated by SWI/SNF action. Collectively, these findings emphasize the close interconnectivity and dynamics of diverse chromatin modifications in cancer and gene control. PMID:18332116

  14. Mercury in coniferous and deciduous upland forests in Northern New England, USA: implications from climate change

    NASA Astrophysics Data System (ADS)

    Richardson, J. B.; Friedland, A. J.

    2015-07-01

    Climatic changes in the northeastern US are expected to cause coniferous stands to transition to deciduous stands over the next hundred years. Mercury (Hg) sequestration in forest soils may change as a result. In order to understand potential effects of this transition, we studied aboveground vegetation and soils at paired coniferous and deciduous stands on eight mountains in Vermont and New Hampshire, US. Organic horizons at coniferous stands accumulated more Total Hg (THg) (42 ± 6 g ha-1) than deciduous stands (30 ± 4 g ha-1). Total Hg pools in the mineral horizons were similar for coniferous (46 ± 8 g ha-1) and deciduous stands (45 ± 7 g ha-1). Soil properties (C, % clay, and pH) explained 56 % of the variation in mineral soil Hg concentration when multiple regressed. Foliar and bole wood Hg concentrations were generally greater for coniferous species than deciduous species. We estimated Hg mean residence time (MRT) in the organic and mineral horizons at coniferous and deciduous stands using a simple two-box model. Organic horizon MRT were longer at coniferous stands (183 ± 44 yr) than deciduous stands (65 ± 15 yr). Mineral soil horizon MRT values were also longer for coniferous stands (386 ± 57 yr) than for deciduous stands (188 ± 27 yr). We concluded that organic horizon Hg accumulation is influenced by vegetation type but mineral horizons are primarily affected by soil properties. Further investigations into the effect of vegetation type on volatilization, atmospheric deposition, and leaching rates are needed to constrain regional Hg cycling rates.

  15. X-Tream quality assurance in synchrotron X-ray microbeam radiation therapy.

    PubMed

    Fournier, Pauline; Cornelius, Iwan; Donzelli, Mattia; Requardt, Herwig; Nemoz, Christian; Petasecca, Marco; Bräuer-Krisch, Elke; Rosenfeld, Anatoly; Lerch, Michael

    2016-09-01

    Microbeam radiation therapy (MRT) is a novel irradiation technique for brain tumours treatment currently under development at the European Synchrotron Radiation Facility in Grenoble, France. The technique is based on the spatial fractionation of a highly brilliant synchrotron X-ray beam into an array of microbeams using a multi-slit collimator (MSC). After promising pre-clinical results, veterinary trials have recently commenced requiring the need for dedicated quality assurance (QA) procedures. The quality of MRT treatment demands reproducible and precise spatial fractionation of the incoming synchrotron beam. The intensity profile of the microbeams must also be quickly and quantitatively characterized prior to each treatment for comparison with that used for input to the dose-planning calculations. The Centre for Medical Radiation Physics (University of Wollongong, Australia) has developed an X-ray treatment monitoring system (X-Tream) which incorporates a high-spatial-resolution silicon strip detector (SSD) specifically designed for MRT. In-air measurements of the horizontal profile of the intrinsic microbeam X-ray field in order to determine the relative intensity of each microbeam are presented, and the alignment of the MSC is also assessed. The results show that the SSD is able to resolve individual microbeams which therefore provides invaluable QA of the horizontal field size and microbeam number and shape. They also demonstrate that the SSD used in the X-Tream system is very sensitive to any small misalignment of the MSC. In order to allow as rapid QA as possible, a fast alignment procedure of the SSD based on X-ray imaging with a low-intensity low-energy beam has been developed and is presented in this publication. PMID:27577773

  16. Assessment of optical CT as a future QA tool for synchrotron x-ray microbeam therapy

    NASA Astrophysics Data System (ADS)

    McErlean, Ciara M.; Bräuer-Krisch, Elke; Adamovics, John; Doran, Simon J.

    2016-01-01

    Synchrotron microbeam radiation therapy (MRT) is an advanced form of radiotherapy for which it is extremely difficult to provide adequate quality assurance. This may delay or limit its clinical uptake, particularly in the paediatric patient populations for whom it could be especially suitable. This study investigates the extent to which new developments in 3D dosimetry using optical computed tomography (CT) can visualise MRT dose distributions, and assesses what further developments are necessary before fully quantitative 3D measurements can be achieved. Two experiments are reported. In the first cylindrical samples of the radiochromic polymer PRESAGE® were irradiated with different complex MRT geometries including multiport treatments of collimated ‘pencil’ beams, interlaced microplanar arrays and a multiport treatment using an anthropomorphic head phantom. Samples were scanned using transmission optical CT. In the second experiment, optical CT measurements of the biologically important peak-to-valley dose ratio (PVDR) were compared with expected values from Monte Carlo simulations. The depth-of-field (DOF) of the optical CT system was characterised using a knife-edge method and the possibility of spatial resolution improvement through deconvolution of a measured point spread function (PSF) was investigated. 3D datasets from the first experiment revealed excellent visualisation of the 50 μm beams and various discrepancies from the planned delivery dose were found. The optical CT PVDR measurements were found to be consistently 30% of the expected Monte Carlo values and deconvolution of the microbeam profiles was found to lead to increased noise. The reason for the underestimation of the PVDR by optical CT was attributed to lack of spatial resolution, supported by the results of the DOF characterisation. Solutions are suggested for the outstanding challenges and the data are shown already to be useful in identifying potential treatment anomalies.

  17. Independent effect of type 2 diabetes beyond characteristic comorbidities and medications on immediate but not continued knee extensor exercise hyperemia

    PubMed Central

    Poitras, Veronica J.; Bentley, Robert F.; Hopkins-Rosseel, Diana H.; LaHaye, Stephen A.

    2015-01-01

    We tested the hypothesis that type 2 diabetes (T2D), when present in the characteristic constellation of comorbidities (obesity, hypertension, dyslipidemia) and medications, slows the dynamic adjustment of exercising muscle perfusion and blunts the steady state relative to that of controls matched for age, body mass index, fitness, comorbidities, and non-T2D medications. Thirteen persons with T2D and 11 who served as controls performed rhythmic single-leg isometric quadriceps exercise (rest-to-6 kg and 6-to-12 kg transitions, 5 min at each intensity). Measurements included leg blood flow (LBF, femoral artery ultrasound), mean arterial pressure (MAP, finger photoplethysmography), and leg vascular conductance (LVK, calculated). Dynamics were quantified using mean response time (MRT). Measures of amplitude were also used to compare response adjustment: the change from baseline to 1) the peak initial response (greatest 1-s average in the first 10 s; ΔLBFPIR, ΔLVKPIR) and 2) the on-transient (average from curve fit at 15, 45, and 75 s; ΔLBFON, ΔLVKON). ΔLBFPIR was significantly blunted in T2D vs. control individuals (P = 0.037); this was due to a tendency for reduced ΔLVKPIR (P = 0.063). In contrast, the overall response speed was not different between groups (MRT P = 0.856, ΔLBFON P = 0.150) nor was the change from baseline to steady state (P = 0.204). ΔLBFPIR, ΔLBFON, and LBF MRT did not differ between rest-to-6 kg and 6-to-12 kg workload transitions (all P > 0.05). Despite a transient amplitude impairment at the onset of exercise, there is no robust or consistent effect of T2D on top of the comorbidities and medications typical of this population on the overall dynamic adjustment of LBF, or the steady-state levels achieved during low- or moderate-intensity exercise. PMID:26048976

  18. Tsunami, post-tsunami malaria situation in Nancowry group of islands, Nicobar district, Andaman and Nicobar Islands

    PubMed Central

    Manimunda, Sathya Prakash; Sugunan, Attayoor Purushottaman; Sha, Wajid Ali; Singh, Shiv Shankar; Shriram, Ananganallur Nagarajan; Vijayachari, Paluru

    2011-01-01

    Background & objectives: Due to tsunami in 2004 a large proportion of population in Nicobar group of Islands become homeless, and in 2006 large scale labour migration took place to construct the houses. In 2008, a significant increase in malaria incidence was observed in this area. Therefore, in March 2008, the situation of malaria was assessed in Nancowry Islands in Nicobar District to study the reasons for the observed upsurge in the number of cases, and to suggest public health measures to control the infection. Methods: The methods included a retrospective analysis of long term trend in the behaviour of malaria over the years from 2001 to 2008, analysis of the acute malaria situation, and rapid fever and malaria parasitemia survey along with environmental component. Mass radical therapy (MRT) and post-intervention parasitemia survey were carried out. The malaria situation in the aftermath of MRT was analysed. Results: During the post tsunami year (2005) there was a large increase in the incidence of malaria and this trend continued till 2008. The percentage of Plasmodium falciparum increased from 23 to 53 per cent from 2006 to 2007 that coincides with the labour influx from mainland. The study showed that Nancowry was highly endemic, with high transmission setting, and high risk area for malaria. Though, more number of migrant labourers suffered fever (75 vs 20%) and sought malaria treatment over past month but parasitemia survey showed higher point prevalence of malaria among native tribes (7.4 vs 6.5%). Post-MRT, there was a decline in the occurrence of malaria, though it did not last long. Interpretation & conclusions: The study findings suggest that the migrant workers hailing from non-endemic or moderately endemic settings became victims of malaria in epidemic proportion in high endemic and high transmission setting. To find out the reasons for deterioration of malaria situation at Nancowry in the aftermath of tsunami requires further research. PMID

  19. THE INFLUENCE OF SUBMERGED MACROPHYTES ON SEDIMENTARY DIATOM ASSEMBLAGES(1).

    PubMed

    Vermaire, Jesse C; Prairie, Yves T; Gregory-Eaves, Irene

    2011-12-01

    Submerged macrophytes are a central component of lake ecosystems; however, little is known regarding their long-term response to environmental change. We have examined the potential of diatoms as indicators of past macrophyte biomass. We first sampled periphyton to determine whether habitat was a predictor of diatom assemblage. We then sampled 41 lakes in Quebec, Canada, to evaluate whether whole-lake submerged macrophyte biomass (BiomEpiV) influenced surface sediment diatom assemblages. A multivariate regression tree (MRT) was used to construct a semiquantitative model to reconstruct past macrophyte biomass. We determined that periphytic diatom assemblages on macrophytes were significantly different from those on wood and rocks (ANOSIM R = 0.63, P < 0.01). A redundancy analysis (RDA) of the 41-lake data set identified BiomEpiV as a significant (P < 0.05) variable in structuring sedimentary diatom assemblages. The MRT analysis classified the lakes into three groups. These groups were (A) high-macrophyte, nutrient-limited lakes (BiomEpiV ≥525 μg · L(-1) ; total phosphorus [TP] <35 μg · L(-1) ; 23 lakes); (B) low-macrophyte, nutrient-limited lakes (BiomEpiV <525 μg · L(-1) ; TP <35 μg · L(-1) ; 12 lakes); and (C) eutrophic lakes (TP ≥35 μg · L(-1) ; six lakes). A semiquantitative model correctly predicted the MRT group of the lake 71% of the time (P < 0.001). These results suggest that submerged macrophytes have a significant influence on diatom community structure and that sedimentary diatom assemblages can be used to infer past macrophyte abundance. PMID:27020346

  20. The effect of basketball training on the muscle strength of adults with mental retardation.

    PubMed

    Tsimaras, Vasilios K; Samara, Christina A; Kotzamanidou, Marianna C; Bassa, Eleni I; Fotiadou, Eleni G; Kotzamanidis, Christos M

    2009-12-01

    The purpose of this study was to evaluate the effect of basketball training on the muscle strength of adults with mental retardation (MR). Twenty-four adults with and without MR were separated into 3 groups. Eight adults (mean age 25.4 years) with normal IQ constituted the control group (NIQ). Eight adults (mean age 26.5 years) with MR and all participating in a 4-year systematic basketball exercise program constituted the trained group (MR-T), and 8 adults (mean age 25.3 years) with MR exercised occasionally for recreational reasons formed the MR-R group. Parameters measured were isometric and isokinetic concentric and eccentric muscle strength. All subjects performed a leg strength test on a Cybex Norm isokinetic dynamometer. Analysis of variance was used to examine mean differences between the values of the 3 groups. A significance level of 0.05 was used for all tests. The NIQ group showed a statistically significant difference in all measured values compared to the MR groups. The MR-T group presented higher absolute and relative torque scores for both knee extensors and flexors than the MR-R group, whereas the MR-R group presented statistically higher antagonistic activity for both knee extensors and flexors than the MR-T group. In addition, both MR groups presented statistically higher antagonistic activity for both knee extensors and flexors compared to the NIQ group. Data support participation on a systematic and well-designed basketball training program to improve muscle strength levels of adults with MR. Participation in basketball without necessarily focusing on developing specific fitness components may be an effective training strategy for the promotion of strength of adults with MR.

  1. Fine Root Longevity Still Under Debate

    NASA Astrophysics Data System (ADS)

    Keel, S. G.; Blackburn, M.; Campbell, C.; Högberg, M. N.; Richter, A.; Wild, B.; Högberg, P.

    2008-12-01

    Assuming that fine roots (< 2 mm in diameter) turn over once per year, they represent a third of the global annual net primary productivity. These turnover estimates are based on rhizotron studies, where root longevity is determined by monitoring the appearance/disappearance of roots on a screen, which is inserted into the soil. Much slower fine root turnover rates were found using carbon (C) isotope methods (either 14C dating or continuous 13C-labelling), resulting in root longevities of several years. Stable C isotope tracer experiments, are argued to overestimate fine root longevities, mainly because the smallest roots with the highest turn over, are easily missed during sampling. The goal of the present study was therefore to carry out a C-labelling experiment, and specifically focus on the finest roots, namely root tips. In addition we sampled whole fine roots (<1 mm and 1-3 mm in diameter), as in other studies. We pulse labelled 14-year-old Pinus sylvestris (Pine) trees in the field for only three hours with highly 13C-enriched CO2 (24 atom percent). The mean residence time (MRT) of recently assimilated C in root tips was determined, as a measure for root longevity. Already two days after labelling, recent C had been translocated from the crowns to fine roots indicating rapid belowground C allocation. 13C signals in root tips were stronger than in whole roots, which shows that they are the most active part of the root system. MRT of C calculated using first order exponential decay functions of C in bulk roots were around 20 days in both <1mm and 1-3mm roots and 29 days in root tips. A rapid decline in 13C signals was observed which could be explained by a rapid decrease in the signal of the sucrose pool, which had a MRT of 5 days. However, part of the labelled C had been allocated to a pool with a slower turnover rate (most likely structural compounds such as cellulose) as indicated by persisting 13C signals measured 120 days after labelling. MRT of C in

  2. Digesta retention and fibre digestion in maras (Dolichotis patagonum) and guinea-pigs.

    PubMed

    Sakaguchi, E; Nippashi, K; Endoh, G

    1992-04-01

    1. Digestibilities of feed and turnover time (1/k), transit time (TT) and mean retention time (MRT: 1/k+TT) of fluid and particle markers were measured in maras (Dolichotis patagonum) and guinea-pigs (Cavia procellus) fed a diet containing 50% alfalfa. 2. The digestibility of fibre was similar in both animals, however, the digestibilities of crude protein (nitrogen x 6.25) and crude ash were lower in the mara than in the guinea-pig. 3. 1/k of the digesta markers were similar in both animals, suggesting that the two animals possess similar dilution and retention time of digesta in their caecum and proximal colon. PMID:1351463

  3. [Sigmoidoperianal fistula associated with diverticulitis and Cul de Sac situation--diagnostics and therapy].

    PubMed

    Weyand, G; Rinast, E; Englert, A; Houf, M

    2002-07-01

    We report on the case of a 64-year-old female patient who presented herself in our outpatient clinic because of a perianal fistula with recurrent abscesses. We describe the step diagnostics and the surgical treatment of the causal sigmoido-perianal fistula with diverticulitis and Cul de sac situation. Clinical examination, fistulography, colonoscopy and MRT were part of the precise representation and preparation for the high anterior rectosigmoidal resection with simultaneous rectopexy according to Sudeck which were performed without complications. The sigmoidoperianal fistula must be taken into account as a differential diagnosis of a recalcitrant high perianal fistula. PMID:12122593

  4. Regional Groundwater Processes and Flow Dynamics from Age Tracer Data

    NASA Astrophysics Data System (ADS)

    Morgenstern, Uwe; Stewart, Mike K.; Matthews, Abby

    2016-04-01

    Age tracers are now used in New Zealand on regional scales for quantifying the impact and lag time of land use and climate change on the quantity and quality of available groundwater resources within the framework of the National Policy Statement for Freshwater Management 2014. Age tracers provide measurable information on the dynamics of groundwater systems and reaction rates (e.g. denitrification), essential for conceptualising the regional groundwater - surface water system and informing the development of land use and groundwater flow and transport models. In the Horizons Region of New Zealand, around 200 wells have tracer data available, including tritium, SF6, CFCs, 2H, 18O, Ar, N2, CH4 and radon. Well depths range from shallower wells in gravel aquifers in the Horowhenua and Tararua districts, and deeper wells in the aquifers between Palmerston North and Wanganui. Most of the groundwater samples around and north of the Manawatu River west of the Tararua ranges are extremely old (>100 years), even from relatively shallow wells, indicating that these groundwaters are relatively disconnected from fresh surface recharge. The groundwater wells in the Horowhenua tap into a considerably younger groundwater reservoir with groundwater mean residence time (MRT) of 10 - 40 years. Groundwater along the eastern side of the Tararua and Ruahine ranges is significantly younger, typically <5 years MRT. Vertical groundwater recharge rates, as deduced from groundwater depth and MRT, are extremely low in the central coastal area, consistent with confined groundwater systems, or with upwelling of old groundwater close to the coast. Very low vertical recharge rates along the Manawatu River west of the Manawatu Gorge indicate upwelling groundwater conditions in this area, implying groundwater discharge into the river is more likely here than loss of river water into the groundwater system. High recharge rates observed at several wells in the Horowhenua area and in the area east of

  5. Micrometer-resolved film dosimetry using a microscope in microbeam radiation therapy

    SciTech Connect

    Bartzsch, Stefan Oelfke, Uwe; Lott, Johanna; Welsch, Katrin; Bräuer-Krisch, Elke

    2015-07-15

    Purpose: Microbeam radiation therapy (MRT) is a still preclinical tumor therapy approach that uses arrays of a few tens of micrometer wide parallel beams separated by a few 100 μm. The production, measurement, and planning of such radiation fields are a challenge up to now. Here, the authors investigate the feasibility of radiochromic film dosimetry in combination with a microscopic readout as a tool to validate peak and valley doses in MRT, which is an important requirement for a future clinical application of the therapy. Methods: Gafchromic{sup ®} HD-810 and HD-V2 films are exposed to MRT fields at the biomedical beamline ID17 of the European Synchrotron Radiation Facility (ESRF) and are afterward scanned with a microscope. The measured dose is compared with Monte Carlo calculations. Image analysis tools and film handling protocols are developed that allow accurate and reproducible dosimetry. The performance of HD-810 and HD-V2 films is compared and a detailed analysis of the resolution, noise, and energy dependence is carried out. Measurement uncertainties are identified and analyzed. Results: The dose was measured with a resolution of 5 × 1000 μm{sup 2} and an accuracy of 5% in the peak and between 10% and 15% in the valley region. As main causes for dosimetry uncertainties, statistical noise, film inhomogeneities, and calibration errors were identified. Calibration errors strongly increase at low doses and exceeded 3% for doses below 50 and 70 Gy for HD-V2 and HD-810 films, respectively. While the grain size of both film types is approximately 2 μm, the statistical noise in HD-V2 is much higher than in HD-810 films. However, HD-810 films show a higher energy dependence at low photon energies. Conclusions: Both film types are appropriate for dosimetry in MRT and the microscope is superior to the microdensitometer used before at the ESRF with respect to resolution and reproducibility. However, a very careful analysis of the image data is required

  6. Digestive capacity in weanling and mature horses.

    PubMed

    Earing, J E; Lawrence, L M; Hayes, S H; Brummer, M; Vanzant, E

    2013-05-01

    The ability of young and mature horses to digest DM, OM, and NDF was compared using 6 weanling colts and 6 mature (13.2 ± 3.0 yr) geldings. Each colt was paired with a gelding, and the pair was adapted to a diet containing 67% alfalfa cubes and 33% concentrate for 21 d. During the adaptation period, horses were accustomed to housing and all handling procedures. The adaptation period was also used to adjust the amount of feed offered to minimize orts and to maintain similar rates of intake within a pair. After the adaptation period, a 5-d fecal collection period using fecal collection harnesses ensued. The average age of the weanling colts at the start of the 5-d collection period was 181.8 ± 2.9 d. On the morning of the first collection day, Co-EDTA (9 mg Co/kg BW(0.75)) and ytterbium-labeled hay fiber (9 mg Yb/kg BW(0.75)) were added to the concentrate portion of the diet, and horses were closely observed for complete consumption of the markers before additional feed was offered. The fecal collection bags were emptied every 1 to 2 h, and each collection was weighed and subsampled for later measurement of Co and Yb concentrations, which were used to determine the mean retention time (MRT) of the fluid and particulate phases of digesta, respectively. The remaining feces for each horse were composited each day and then subsampled for measurement of DM digestibility (DMD), NDF digestibility (NDFD), and OM digestibility (OMD). During the fecal collection period, DMI was similar between colts and geldings (91.4 and 91.2 g/kg BW(0.75), respectively). There were no differences between colts and mature geldings for DMD, OMD, or NDFD. Across both ages, the MRT of the particulate phase was 24.9 h compared with 21.8 h for the fluid phase (P = 0.002). However, MRT for the particulate phase was not different between colts and mature geldings (24.7 and 25.2 h, respectively). There was no difference in the MRT for the fluid phase between colts and mature geldings (21.5 and 22

  7. Elaboration over a Discourse Facilitates Retrieval in Sentence Processing.

    PubMed

    Troyer, Melissa; Hofmeister, Philip; Kutas, Marta

    2016-01-01

    Language comprehension requires access to stored knowledge and the ability to combine knowledge in new, meaningful ways. Previous work has shown that processing linguistically more complex expressions ('Texas cattle rancher' vs. 'rancher') leads to slow-downs in reading during initial processing, possibly reflecting effort in combining information. Conversely, when this information must subsequently be retrieved (as in filler-gap constructions), processing is facilitated for more complex expressions, possibly because more semantic cues are available during retrieval. To follow up on this hypothesis, we tested whether information distributed across a short discourse can similarly provide effective cues for retrieval. Participants read texts introducing two referents (e.g., two senators), one of whom was described in greater detail than the other (e.g., 'The Democrat had voted for one of the senators, and the Republican had voted for the other, a man from Ohio who was running for president'). The final sentence (e.g., 'The senator who the {Republican/Democrat}had voted for…') contained a relative clause picking out either the Many-Cue referent (with 'Republican') or the One-Cue referent (with 'Democrat'). We predicted facilitated retrieval (faster reading times) for the Many-Cue condition at the verb region ('had voted for'), where readers could understand that 'The senator' is the object of the verb. As predicted, this pattern was observed at the retrieval region and continued throughout the rest of the sentence. Participants also completed the Author/Magazine Recognition Tests (ART/MRT; Stanovich and West, 1989), providing a proxy for world knowledge. Since higher ART/MRT scores may index (a) greater experience accessing relevant knowledge and/or (b) richer/more highly structured representations in semantic memory, we predicted it would be positively associated with effects of elaboration on retrieval. We did not observe the predicted interaction between ART/MRT

  8. Effects of assuming constant optical scattering on measurements of muscle oxygenation by near-infrared spectroscopy during exercise.

    PubMed

    Ferreira, Leonardo F; Hueber, Dennis M; Barstow, Thomas J

    2007-01-01

    The aim of this study was to examine the effects of assuming constant reduced scattering coefficient (mu'(s)) on the muscle oxygenation response to incremental exercise and its recovery kinetics. Fifteen subjects (age: 24 +/- 5 yr) underwent incremental cycling exercise. Frequency domain near-infrared spectroscopy (NIRS) was used to estimate deoxyhemoglobin concentration {[deoxy(Hb+Mb)]} (where Mb is myoglobin), oxyhemoglobin concentration {[oxy(Hb+Mb)]}, total Hb concentration (Total[Hb+Mb]), and tissue O(2) saturation (Sti(O(2))), incorporating both continuous measurements of mu'(s) and assuming constant mu'(s). When measuring mu'(s), we observed significant changes in NIRS variables at peak work rate Delta[deoxy(Hb+Mb)] (15.0 +/- 7.8 microM), Delta[oxy(Hb+Mb)] (-4.8 +/- 5.8 microM), DeltaTotal[Hb+Mb] (10.9 +/- 8.4 microM), and DeltaSti(O(2))(-11.8 +/- 4.1%). Assuming constant mu'(s) resulted in greater (P < 0.01 vs. measured mu'(s)) changes in the NIRS variables at peak work rate, where Delta[deoxy(Hb+Mb)] = 24.5 +/- 15.6 microM, Delta[oxy(Hb+Mb)] = -9.7 +/- 8.2 microM, DeltaTotal[Hb+Mb] = 14.8 +/- 8.7 microM, and DeltaSti(O(2))= -18.7 +/- 8.4%. Regarding the recovery kinetics, the large 95% confidence intervals (CI) for the difference between those determine measuring mu'(s) and assuming constant mu'(s) suggested poor agreement between methods. For the mean response time (MRT), which describes the overall kinetics, the 95% confidence intervals were MRT - [deoxy(Hb+Mb)] = 26.7 s; MRT - [oxy(Hb+Mb)] = 11.8 s, and MRT - Sti(O(2))= 11.8 s. In conclusion, mu'(s) changed from light to peak exercise. Furthermore, assuming a constant mu'(s) led to an overestimation of the changes in NIRS variables during exercise and distortion of the recovery kinetics. PMID:17023569

  9. Elaboration over a Discourse Facilitates Retrieval in Sentence Processing.

    PubMed

    Troyer, Melissa; Hofmeister, Philip; Kutas, Marta

    2016-01-01

    Language comprehension requires access to stored knowledge and the ability to combine knowledge in new, meaningful ways. Previous work has shown that processing linguistically more complex expressions ('Texas cattle rancher' vs. 'rancher') leads to slow-downs in reading during initial processing, possibly reflecting effort in combining information. Conversely, when this information must subsequently be retrieved (as in filler-gap constructions), processing is facilitated for more complex expressions, possibly because more semantic cues are available during retrieval. To follow up on this hypothesis, we tested whether information distributed across a short discourse can similarly provide effective cues for retrieval. Participants read texts introducing two referents (e.g., two senators), one of whom was described in greater detail than the other (e.g., 'The Democrat had voted for one of the senators, and the Republican had voted for the other, a man from Ohio who was running for president'). The final sentence (e.g., 'The senator who the {Republican/Democrat}had voted for…') contained a relative clause picking out either the Many-Cue referent (with 'Republican') or the One-Cue referent (with 'Democrat'). We predicted facilitated retrieval (faster reading times) for the Many-Cue condition at the verb region ('had voted for'), where readers could understand that 'The senator' is the object of the verb. As predicted, this pattern was observed at the retrieval region and continued throughout the rest of the sentence. Participants also completed the Author/Magazine Recognition Tests (ART/MRT; Stanovich and West, 1989), providing a proxy for world knowledge. Since higher ART/MRT scores may index (a) greater experience accessing relevant knowledge and/or (b) richer/more highly structured representations in semantic memory, we predicted it would be positively associated with effects of elaboration on retrieval. We did not observe the predicted interaction between ART/MRT

  10. Elaboration over a Discourse Facilitates Retrieval in Sentence Processing

    PubMed Central

    Troyer, Melissa; Hofmeister, Philip; Kutas, Marta

    2016-01-01

    Language comprehension requires access to stored knowledge and the ability to combine knowledge in new, meaningful ways. Previous work has shown that processing linguistically more complex expressions (‘Texas cattle rancher’ vs. ‘rancher’) leads to slow-downs in reading during initial processing, possibly reflecting effort in combining information. Conversely, when this information must subsequently be retrieved (as in filler-gap constructions), processing is facilitated for more complex expressions, possibly because more semantic cues are available during retrieval. To follow up on this hypothesis, we tested whether information distributed across a short discourse can similarly provide effective cues for retrieval. Participants read texts introducing two referents (e.g., two senators), one of whom was described in greater detail than the other (e.g., ‘The Democrat had voted for one of the senators, and the Republican had voted for the other, a man from Ohio who was running for president’). The final sentence (e.g., ‘The senator who the {Republican/Democrat}had voted for…’) contained a relative clause picking out either the Many-Cue referent (with ‘Republican’) or the One-Cue referent (with ‘Democrat’). We predicted facilitated retrieval (faster reading times) for the Many-Cue condition at the verb region (‘had voted for’), where readers could understand that ‘The senator’ is the object of the verb. As predicted, this pattern was observed at the retrieval region and continued throughout the rest of the sentence. Participants also completed the Author/Magazine Recognition Tests (ART/MRT; Stanovich and West, 1989), providing a proxy for world knowledge. Since higher ART/MRT scores may index (a) greater experience accessing relevant knowledge and/or (b) richer/more highly structured representations in semantic memory, we predicted it would be positively associated with effects of elaboration on retrieval. We did not observe the

  11. Magnetic Resonance (MR) rectography in diagnostics of small-size rectal neoplasms

    NASA Astrophysics Data System (ADS)

    Usova, AV; Frolova, IG; Trukhacheva, NG; Cheremisina, OV; Afanas'ev, SG

    2016-02-01

    Purpose was the assessment of diagnostic efficiency of MR-rectography in diagnostics of small-size rectal neoplasms. 12 patients with polyps and small tumors of a rectum are examined, the size of detected neoplasms varied in the range 3-18 mm. Native MRI and MRI with retrograde contrasting by ultrasonic gel was carried out. Results of MRI are compared with results of videocolonoscopy. Sensitivity of native MRT was 24%, MR- rectography was 88%. MR-rectography can be used in diagnostics of small-size rectal neoplasms.

  12. [Treatment of choroid melanoma by Gamma-Knife radiosurgery].

    PubMed

    Devin, F; Regis, J; Berros, P; Manera, L; Porcheron, D; Sedan, R; Peragut, J C; Saracco, J B

    1996-01-01

    Conservative treatment of uveal melanomas by Gamma Knife Radiosurgery is based on the use of cross fire technique with 201 Cobalt60 sources. A following of 13 months is available for the first case operated by Gamma-Knife Surgery in France. Technical baselines and one year preliminary results are reported. The diagnosis of uveal melanoma T3NOMO was established by converging results of clinical examination, angiography and echography. The definition of the target was based on stereotactic MRT examination. We delivered a dose of 50 Gys to the marginal isodose (50%). Today, one year after treatment the tumor decreased, the visual function was preserved. There were no side effect or complication.

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

    NASA Astrophysics Data System (ADS)

    Kralik, Martin

    2014-05-01

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

  14. Retention time of digesta in the gastrointestinal tract of growing Saanen goats.

    PubMed

    Leite, R F; Krizsan, S J; Figueiredo, F O M; Carvalho, V B; Teixeira, I A M A; Huhtanen, P

    2015-08-01

    This study examined the effect of increased BW on mean retention time (MRT) of both particulate and solute marker, gastrointestinal tract (GIT) development, and fiber digestion in the whole tract of growing Saanen goats using the slaughter technique. A total of 58 Saanen goats with initial BW of 15.7 ± 0.9 kg were allocated into 9 treatments with a 3 × 3 factorial arrangement consisting of 3 sexes (female, castrated males, and intact males) and 3 slaughter weights (initial, intermediate, and final; target BW of 16, 23, and 30 kg at slaughter, respectively). They were fed twice daily (0700 and 1600 h) with the identical diets for ad libitum intake. Mean retention time of particulate matter was estimated by in situ determination of indigestible NDF (iNDF), and the MRT of solute marker was determined by Cr-EDTA. Treatment effects were evaluated in a split-plot design, with sex as the main plot and slaughter weight as the subplot. Orthogonal polynomial contrasts were used to determine linear and quadratic effects of slaughter weight, whereas the effect of sex was compared using the Tukey test. The effects of sex and sex × slaughter weight were not significant for most of variables evaluated. The results showed that DMI (% BW) linearly decreased as slaughter weight increased ( < 0.01). Generally wet weight of the total GIT tissues (% BW) decreased and digesta pool sizes (g) linearly increased with increasing slaughter weight ( ≤ 0.05). The ratio of iNDF:NDF for both ingested diet and reticulorumen digesta linearly increased as slaughter weight increased ( ≤ 0.05). The MRT of particles did not change with increasing slaughter weight ( = 0.94). Mean retention time of particulate matter linearly increased in the omasum but linearly decreased in the abomasum with increasing slaughter weight ( < 0.01). Mean retention time of solute marker in the forestomachs linearly increased with increasing slaughter weight ( < 0.01). The results revealed a decreased selectivity

  15. Retention time of digesta in the gastrointestinal tract of growing Saanen goats.

    PubMed

    Leite, R F; Krizsan, S J; Figueiredo, F O M; Carvalho, V B; Teixeira, I A M A; Huhtanen, P

    2015-08-01

    This study examined the effect of increased BW on mean retention time (MRT) of both particulate and solute marker, gastrointestinal tract (GIT) development, and fiber digestion in the whole tract of growing Saanen goats using the slaughter technique. A total of 58 Saanen goats with initial BW of 15.7 ± 0.9 kg were allocated into 9 treatments with a 3 × 3 factorial arrangement consisting of 3 sexes (female, castrated males, and intact males) and 3 slaughter weights (initial, intermediate, and final; target BW of 16, 23, and 30 kg at slaughter, respectively). They were fed twice daily (0700 and 1600 h) with the identical diets for ad libitum intake. Mean retention time of particulate matter was estimated by in situ determination of indigestible NDF (iNDF), and the MRT of solute marker was determined by Cr-EDTA. Treatment effects were evaluated in a split-plot design, with sex as the main plot and slaughter weight as the subplot. Orthogonal polynomial contrasts were used to determine linear and quadratic effects of slaughter weight, whereas the effect of sex was compared using the Tukey test. The effects of sex and sex × slaughter weight were not significant for most of variables evaluated. The results showed that DMI (% BW) linearly decreased as slaughter weight increased ( < 0.01). Generally wet weight of the total GIT tissues (% BW) decreased and digesta pool sizes (g) linearly increased with increasing slaughter weight ( ≤ 0.05). The ratio of iNDF:NDF for both ingested diet and reticulorumen digesta linearly increased as slaughter weight increased ( ≤ 0.05). The MRT of particles did not change with increasing slaughter weight ( = 0.94). Mean retention time of particulate matter linearly increased in the omasum but linearly decreased in the abomasum with increasing slaughter weight ( < 0.01). Mean retention time of solute marker in the forestomachs linearly increased with increasing slaughter weight ( < 0.01). The results revealed a decreased selectivity

  16. Microbial carbon recycling: an underestimated process controlling soil carbon dynamics - Part 2: A C3-C4 vegetation change field labelling experiment

    NASA Astrophysics Data System (ADS)

    Basler, A.; Dippold, M.; Helfrich, M.; Dyckmans, J.

    2015-11-01

    The mean residence times (MRT) of different compound classes of soil organic matter (SOM) do not match their inherent recalcitrance to decomposition. One reason for this is the stabilization within the soil matrix, but recycling, i.e. the reuse of "old" organic material to form new biomass may also play a role as it uncouples the residence times of organic matter from the lifetime of discrete molecules in soil. We analysed soil sugar dynamics in a natural 30-year old labelling experiment after a wheat-maize vegetation change to determine the extent of recycling and stabilization by assessing differences in turnover dynamics between plant and microbial-derived sugars: while plant-derived sugars are only affected by stabilization processes, microbial sugars may be subject to both, stabilization and recycling. To disentangle the dynamics of soil sugars, we separated different density fractions (free particulate organic matter (fPOM), light occluded particulate organic matter (≤ 1.6 g cm-3; oPOM1.6), dense occluded particulate organic matter (≤ 2 g cm-3; oPOM2) and mineral-associated organic matter (> 2 g cm-3; mineral)) of a silty loam under long-term wheat and maize cultivation. The isotopic signature of neutral sugars was measured by high pressure liquid chromatography coupled to isotope ratio mass spectrometry (HPLC/IRMS), after hydrolysis with 4 M Trifluoroacetic acid. While apparent MRT of sugars were comparable to total organic carbon in the bulk soil and mineral fraction, the apparent MRT of sugar carbon in the oPOM fractions were considerably lower than those of the total carbon of these fractions. This indicates that oPOM formation was fuelled by microbial activity feeding on new plant input. In the bulk soil, MRT of the mainly plant-derived xylose were significantly lower than those of mainly microbial-derived sugars like galactose, rhamnose, fucose, indicating that recycling of organic matter is an important factor regulating organic matter dynamics in

  17. Discrepancy between femoral and capillary blood flow kinetics during knee extension exercise.

    PubMed

    Schlup, S J; Ade, C J; Broxterman, R M; Barstow, T J

    2015-12-01

    Capillary blood flow (QCAP) kinetics have previously been shown to be significantly slower than femoral artery (QFA) kinetics following the onset of dynamic knee extension exercise. If the increase in QCAP does not follow a similar time course to QFA, then a substantial proportion of the available blood flow is not distributed to the working muscle. One possible explanation for this discrepancy is that blood flow also increases to the nonworking lower leg muscles. Therefore, the present study aimed to determine if a reduction in lower limb blood flow, via arterial occlusion below the knee, alters the kinetics of QFA and QCAP during knee extension exercise, and thus provide insight into the potential mechanisms controlling the rapid increase in QFA. Subjects performed a ramp max test to determine the work rate at which gas exchange threshold (GET) occurred. At least four constant work rate trials with and without below-knee occlusion were conducted at work rates eliciting ∼ 80% GET. Pulmonary gas exchange, near-infrared spectroscopy and QFA measurements were taken continuously during each exercise bout. Muscle oxygen uptake (VO2m) and deoxy[hemoglobin+myoglobin] were used to estimate QCAP. There was no significant difference between the uncuffed and cuffed conditions in any response (P>0.05). The mean response times (MRT) of QFA were 18.7 ± 14.2s (uncuffed) and 24.6 ± 14.9s (cuffed). QCAP MRTs were 51.8 ± 23.4s (uncuffed) and 56.7 ± 23.2s (cuffed), which were not significantly different from the time constants (τ) of VO2m (39.7 ± 23.2s (uncuffed) and 46.3 ± 24.1s (cuffed). However, the MRT of QFA was significantly faster (P<0.05) than the MRT of QCAP and τVO2m. τVO2m and MRT QCAP were significantly correlated and estimated QCAP kinetics tracked VO2m following exercise onset. Cuffing below the knee did not significantly change the kinetics of QFA, QCAP or VO2m, although an effect size of 1.02 suggested that a significant effect on QFA may have been hidden

  18. Analysis of catchment behavior using residence time distributions with application to the Thuringian Basin

    NASA Astrophysics Data System (ADS)

    Prykhodko, Vladyslav; Heße, Falk; Kumar, Rohini; Samaniego, Luis; Attinger, Sabine

    2014-05-01

    Residence time distribution (RTD), as presented e.g. by Botter et al., are a novel mathematical framework for a quantitative characterization of hydrological systems. These distributions contain information about water storage, flow pathways and water sources and therefore improve the classical hydrograph methods by allowing both nonlinear as well as time-dependent dynamics. In our study we extend this previous works by applying this theoretical framework on real-world heterogeneous catchments. To that end we use a catchment-scale hydrological model (mHM) and apply the approach of Botter et al. to each spatial grid cell of mHM. To facilitate the coupling we amended Botter's approach by introducing additional fluxes (like runoff from unsaturated zone) and specifying the structure of the groundwater zone. By virtue of this coupling we could then make use of the realistic hydrological fluxes and state variables as provided by mHM. This allowed us to use both observed (precipitation, temperature, soil type etc.) and modeled data sets and asses their impact on the behavior of the resulting RTD's. We extended the aforementioned framework to analyze large catchments by including geomorphic effect due to the actual arrangement of subcatchments around the channel network using the flood routing algorithm of mHM. Additionally we study dependencies of the stochastic characteristics of RTD's on the meteorological and hydrological processes as well as on the morphological structure of the catchment. As a result we gained mean residence times (MRT) of base flow and groundwater flow on the mesoscale (4km x 4km). We compare the spatial distribution of MRT's with land cover and soil moisture maps as well as driving forces like precipitation and temperature. Results showed that land cover is a major predictor for MRT's whereas its impact on the mean evapotranspiration time was much lower. Additionally we determined the temporal evolution of mean travel times by using time series of

  19. Multi radar tracking and multi sensor tracking in air defence systems

    NASA Astrophysics Data System (ADS)

    Berle, F. J.

    1983-10-01

    The netting of radars and the integration of other complementary sensors provide advantages with respect to system survivability and achieve a better quality air picture because of the resulting higher data rate. The paper describes an MST concept resulting from an extension of an operational MRT system and presents the results of a computer evaluation of the concept, emphasizing the processing of data from passive sensors and radars operating in passive mode. Three examples of different target density and number indicate the difficulties of processing sensor data in a jamming situation. Several possibilities of improvements are indicated.

  20. [Acute perilunar dislocations: algorithm for treatment].

    PubMed

    Towfigh, H

    2001-01-01

    In most cases, perilunar dislocations of the wrist are caused by high speed accidents. Usually these injuries occur by a fall on the dorsiflexed superextension of the hand. The instability caused by injuries of various erticular structures (ligament, bone) show various developmental stages. Clinical symptoms are reduced and painful movement, instability of the carpus, snapping and swelling. The diagnosis is established by X-ray, cinematography, arthrography MRT or CT. Perilunar instability with or without associated fractures and particularly de Quervain must be reduced and treated operatively including suture of the ligament and stabilization of the fracture. PMID:11824286

  1. „Überholen ohne einzuholen“ Die Entwicklung von Technologien für übermorgen in Kernenergie und Mikroelektronik der DDR

    NASA Astrophysics Data System (ADS)

    Barkleit, Gerhard

    Dem nuklearen Patt zwischen Ostblock und westlichem Staatenbündnis ist es nach weitgehend übereinstimmender Auffassung von Politik und Wissenschaft zu danken, dass der "Kalte Krieg" in der zweiten Hälfte des 20. Jahrhunderts nicht zum weltumfassenden Flächenbrand eskalierte. An der raschen Herstellung dieses Patts waren zwei Dresdner Physiker maßgeblich beteiligt, deren einer im Manhattan-Projekt in den USA gearbeitet hatte und später in England der Spionage für die Sowjetunion und des Verrats des Know-how der Atombombe überführt wurde.

  2. Aufbau von organisationsübergreifenden Fehlermanagementprozessen im Projekt IntegraTUM

    NASA Astrophysics Data System (ADS)

    Hommel, Wolfgang; Knittl, Silvia

    Das Projekt IntegraTUM wird in enger Kooperation zwischen der Technischen Universität München (TUM) und dem Leibniz-Rechenzentrum (LRZ) durchgeführt. In diesem Projekt werden Dienste gemeinsam entwickelt, die nachhaltig vom LRZ betrieben werden sollen. Die damit verbundene Rezentralisierung erfordert auch eine enge Kooperation im Falle von technischen Störungen und Fehlern im Betriebsablauf bei diesen Diensten über die Organisationsgrenzen hinweg. Unsere Aktivitäten in diesem organisationsübergreifenden Fehlermanagement werden hier beschrieben.

  3. Teilchenphysik SESAME - Forschung für den Frieden

    NASA Astrophysics Data System (ADS)

    Schopper, Herwig

    2002-01-01

    Unter der Schirmherrschaft der UNESCO entsteht in den kommenden Jahren in Jordanien ein internationales Forschungszentrum, dessen wichtigste Forschungsanlage eine Quelle für Synchrotronstrahlung sein wird. Die SESAME (Synchrotron-Light for Experimental Science and Application in the Middle East) genannte Anlage soll auch dazu beitragen, Vertrauen und Toleranz zwischen Wissenschaftlern und Politikern aus verschiedenen Kulturkreisen und Traditionen zu fördern. Das europäische Teilchenlabor CERN diente hier in mancher Hinsicht als Vorbild. Technische Grundlage für SESAME wird das 1999 stillgelegte Berliner Synchrotron BESSY I sein.

  4. Telesurgery via Unmanned Aerial Vehicle (UAV) with a field deployable surgical robot.

    PubMed

    Lum, Mitchell J H; Rosen, Jacob; King, Hawkeye; Friedman, Diana C W; Donlin, Gina; Sankaranarayanan, Ganesh; Harnett, Brett; Huffman, Lynn; Doarn, Charles; Broderick, Timothy; Hannaford, Blake

    2007-01-01

    Robotically assisted surgery stands to further revolutionize the medical field and provide patients with more effective healthcare. Most robotically assisted surgeries are teleoperated from the surgeon console to the patient where both ends of the system are located in the operating room. The challenge of surgical teleoperation across a long distance was already demonstrated through a wired communication network in 2001. New development has shifted towards deploying a surgical robot system in mobile settings and/or extreme environments such as the battlefield or natural disaster areas with surgeons operating wirelessly. As a collaborator in the HAPs/MRT (High Altitude Platform/Mobile Robotic Telesurgery) project, The University of Washington surgical robot was deployed in the desert of Simi Valley, CA for telesurgery experiments on an inanimate model via wireless communication through an Unmanned Aerial Vehicle (UAV). The surgical tasks were performed telerobotically with a maximum time delay between the surgeon's console (master) and the surgical robot (slave) of 20 ms for the robotic control signals and 200 ms for the video stream. This was our first experiment in the area of Mobile Robotic Telesurgery (MRT). The creation and initial testing of a deployable surgical robot system will facilitate growth in this area eventually leading to future systems saving human lives in disaster areas, on the battlefield or in other remote environments.

  5. Optimization of frequency lowering algorithms for getting the highest speech intelligibility improvement by hearing loss simulation.

    PubMed

    Arıöz, Umut; Günel, Banu

    2015-06-01

    High frequency hearing loss is a growing problem for both children and adults. To overcome this impairment, different frequency lowering methods (FLMs) were tried from 1930s, however no satisfaction was provided up to now. In this study, for getting higher speech intelligibility, eight combinations of FLMs which were designed originally were tried with simulated sounds onto normal hearing subjects. These improvements were calculated by the difference with standard hearing aid method, amplification. High frequency hearing loss was simulated with the combined suprathreshold effects. An offline study was carried out for each subject for determining the significant methods used in modified rhyme test (MRT) (Subjective measure for intelligibility). Significant methods were determined according to their speech intelligibility index (SII) (Objective measure for intelligibility). All different cases were tried under four noisy environments and a noise free environment. Twelve hearing impaired subjects were simulated by hearing loss simulation (HLS). MRT was developed for Turkish language as a first time. As the results of improvements, total 71 cases were statistically significant for twelve subjects. Eighty-three percent success of FLMs was achieved against amplification for being an alternative method of amplification in noisy environments. For four subjects, all significant methods gave higher improvements than amplification. As conclusion, specific method recommendations for different noisy environments were done for each subject for getting more speech intelligibility.

  6. Influence of induced axial magnetic field on plasma dynamics and radiative characteristics of Z pinches

    SciTech Connect

    Kantsyrev, V. L.; Esaulov, A. A.; Safronova, A. S.; Osborne, G. C.; Shrestha, I.; Weller, M. E.; Stafford, A.; Shlyaptseva, V. V.; Velikovich, A. L.; Rudakov, L. I.; Williamson, K. M.

    2011-10-15

    The influence of an induced axial magnetic field on plasma dynamics and radiative characteristics of Z pinches is investigated. An axial magnetic field was induced in a novel Z-pinch load: a double planar wire array with skewed wires (DPWAsk), which represents a planar wire array in an open magnetic configuration. The induced axial magnetic field suppressed magneto-Rayleigh-Taylor (MRT) instabilities (with m = 0 and m = 1 instability modes) in the Z-pinch plasma. The influence of the initial axial magnetic field on the structure of the plasma column at stagnation was manifested through the formation of a more uniform plasma column compared to a standard double planar wire array (DPWA) load [V. L. Kantsyrev et al., Phys. Plasmas 15, 030704 (2008)]. The DPWAsk load is characterized by suppression of MRT instabilities and by the formation of the sub-keV radiation pulse that occurs before the main x-ray peak. Gradients in plasma parameters along the cathode-anode gap were observed and analyzed for DPWAsk loads made from low atomic number Z (Al) and mid-Z (brass) wires.

  7. The distribution of radioactive ( 3H, 14C) and stable ( 2H, 18O) isotopes in precipitation, surface and groundwaters of NW Yugoslavia

    NASA Astrophysics Data System (ADS)

    Horvatinčić, Nada; Krajcar-Bronić, Ines; Pezdič, Jože; Srdoč, Dušan; Obelić, Bogomil

    1986-11-01

    The isotopic measurements ( 2H, 3H, 18O) of precipitiation in Zagreb (since 1976) and Ljubljana (since 1981) in NW Yugoslavia show seasonal variations typical of the Northern hemisphere. Continuous measurements of tritium concentration in the Sava River ca 10 km upstream from Zagreb have been performed since 1976. Data show a smooth line without periodical changes, but a steady decrease is obvious. The sampling place is situated ca 30 km downstream from the Kr\\vsko Nuclear Power Plant. No change in tritium concentration due to the operation of the power plant has been observed. A comprehensive program of monitoring of the 14C activity in air CO 2 as well as in vegetables, cereals and tree-rings in the surroundings of the Nuclear Power Plant Kr\\vsko has been carried out since 1984. The measurement of 2H and 18O in karst springs of the Korana River catchmet area (Plitvice National Park) gave a meteoric water line equal to δ2H = 7.9 δ18O + 8.5, which is typical of the NW part of Yugoslavia. A fairly constant concentration of 2H and 18O in spring water indicates a thorough mixing of water in the karst aquifers. The mean residence time (MRT) of karst water was determined by measuring monthly tritium activity of spring water. The MRT is very short, ranging between 1 and 4 years on average.

  8. Highly dispersive electron relaxation and colossal thermoelectricity in the correlated semiconductor FeSb2

    NASA Astrophysics Data System (ADS)

    Sun, Peijie; Xu, Wenhu; Tomczak, Jan M.; Kotliar, Gabriel; Søndergaard, Martin; Iversen, Bo B.; Steglich, Frank

    2013-12-01

    We show that the colossal thermoelectric power S (T) observed in the correlated semiconductor FeSb2 below 30 K is accompanied by a huge Nernst coefficient ν (T) and magnetoresistance MR(T). Markedly, the latter two quantities are enhanced in a strikingly similar manner. While in the same temperature range, S (T) of the reference compound FeAs2, which has a seven-times-larger energy gap, amounts to nearly half of that of FeSb2, its ν (T) and MR(T) are intrinsically different to FeSb2: They are smaller by two orders of magnitude and have no common features. Underlying the essentially different thermoelectric properties between FeSb2 and FeAs2, a large mismatch between the electrical and thermal Hall mobilities is found only in the former compound. With the charge transport of FeAs2 successfully captured by the density functional theory, we emphasize a significantly dispersive electron-relaxation time τ (ɛk) related to electron-electron correlations to be at the heart of the peculiar thermoelectricity and magnetoresistance of FeSb2.

  9. Multiple-relaxation-time color-gradient lattice Boltzmann model for simulating two-phase flows with high density ratio

    NASA Astrophysics Data System (ADS)

    Ba, Yan; Liu, Haihu; Li, Qing; Kang, Qinjun; Sun, Jinju

    2016-08-01

    In this paper we propose a color-gradient lattice Boltzmann (LB) model for simulating two-phase flows with high density ratio and high Reynolds number. The model applies a multirelaxation-time (MRT) collision operator to enhance the stability of the simulation. A source term, which is derived by the Chapman-Enskog analysis, is added into the MRT LB equation so that the Navier-Stokes equations can be exactly recovered. Also, a form of the equilibrium density distribution function is used to simplify the source term. To validate the proposed model, steady flows of a static droplet and the layered channel flow are first simulated with density ratios up to 1000. Small values of spurious velocities and interfacial tension errors are found in the static droplet test, and improved profiles of velocity are obtained by the present model in simulating channel flows. Then, two cases of unsteady flows, Rayleigh-Taylor instability and droplet splashing on a thin film, are simulated. In the former case, the density ratio of 3 and Reynolds numbers of 256 and 2048 are considered. The interface shapes and spike and bubble positions are in good agreement with the results of previous studies. In the latter case, the droplet spreading radius is found to obey the power law proposed in previous studies for the density ratio of 100 and Reynolds number up to 500.

  10. Reaction time variability associated with reading skills in poor readers with ADHD.

    PubMed

    Tamm, Leanne; Epstein, Jeffery N; Denton, Carolyn A; Vaughn, Aaron J; Peugh, James; Willcutt, Erik G

    2014-03-01

    Linkages between neuropsychological functioning (i.e., response inhibition, processing speed, reaction time variability) and word reading have been documented among children with attention-deficit/hyperactivity disorder (ADHD) and children with Reading Disorders. However, associations between neuropsychological functioning and other aspects of reading (i.e., fluency, comprehension) have not been well-documented among children with comorbid ADHD and Reading Disorder. Children with ADHD and poor word reading (i.e., ≤25th percentile) completed a stop signal task (SST) and tests of word reading, reading fluency, and reading comprehension. Multivariate multiple regression was conducted predicting the reading skills from SST variables [i.e., mean reaction time (MRT), reaction time standard deviation (SDRT), and stop signal reaction time (SSRT)]. SDRT predicted word reading, reading fluency, and reading comprehension. MRT and SSRT were not associated with any reading skill. After including word reading in models predicting reading fluency and reading comprehension, the effects of SDRT were minimized. Reaction time variability (i.e., SDRT) reflects impairments in information processing and failure to maintain executive control. The pattern of results from this study suggest SDRT exerts its effects on reading fluency and reading comprehension through its effect on word reading (i.e., decoding) and that this relation may be related to observed deficits in higher-level elements of reading.

  11. Modified helix-like instability structure on imploding z-pinch liners that are pre-imposed with a uniform axial magnetic field

    SciTech Connect

    Awe, T. J. Jennings, C. A.; McBride, R. D.; Cuneo, M. E.; Lamppa, D. C.; Martin, M. R.; Rovang, D. C.; Sinars, D. B.; Slutz, S. A.; Owen, A. C.; Gomez, M. R.; Hansen, S. B.; Herrmann, M. C.; Jones, M. C.; McKenney, J. L.; Robertson, G. K.; Rochau, G. A.; Savage, M. E.; Stygar, W. A.; Tomlinson, K.; and others

    2014-05-15

    Recent experiments at the Sandia National Laboratories Z Facility have, for the first time, studied the implosion dynamics of magnetized liner inertial fusion (MagLIF) style liners that were pre-imposed with a uniform axial magnetic field. As reported [T. J. Awe et al., Phys. Rev. Lett. 111, 235005 (2013)] when premagnetized with a 7 or 10 T axial field, these liners developed 3D-helix-like hydrodynamic instabilities; such instabilities starkly contrast with the azimuthally correlated magneto-Rayleigh-Taylor (MRT) instabilities that have been consistently observed in many earlier non-premagnetized experiments. The helical structure persisted throughout the implosion, even though the azimuthal drive field greatly exceeded the expected axial field at the liner's outer wall for all but the earliest stages of the experiment. Whether this modified instability structure has practical importance for magneto-inertial fusion concepts depends primarily on whether the modified instability structure is more stable than standard azimuthally correlated MRT instabilities. In this manuscript, we discuss the evolution of the helix-like instability observed on premagnetized liners. While a first principles explanation of this observation remains elusive, recent 3D simulations suggest that if a small amplitude helical perturbation can be seeded on the liner's outer surface, no further influence from the axial field is required for the instability to grow.

  12. Immunoassay of specific IgE: use of a single point calibration curve in the modified radioallergosorbent test.

    PubMed

    Williams, P B; Dolen, W K; Koepke, J W; Selner, J C

    1992-07-01

    Interest in immunoassay standardization has prompted development of specific IgE assays reporting results related to the international IgE reference. To examine the single point calibration curve employed in the modified RAST assay (MRT) to convert MRT counts to IgE units, independent dilutions of a 25 kU/L total IgE reference and nine allergic sera (three each for short ragweed, cat, and timothy) were made in horse serum and assayed. In a log-log plot, the single point curve was, by definition, linear over its entire range; the dilution curve was curvilinear because of reagent system saturation, which was at 7 kU/L. Curves were not parallel (P less than .001). Allergen-specific dilution curves showed saturation points at values similar to or less than the total IgE system. The linear portions of these curves paralleled the total IgE dilution curve but not the single point curve. This lack of parallelism would have resulted in varying magnitudes of error in estimation of IgE antibody levels in the upper and lower assay ranges, and would imply a lower detection limit for IgE than that which the assay actually has. Modified RAST assay is not appropriate in research or a clinical situation in which accurate quantitative results are needed. Modified RAST assay would furthermore be an inappropriate means of assigning units to proposed reference preparations for standardization.

  13. Thermal human biometeorological conditions and subjective thermal sensation in pedestrian streets in Chengdu, China

    NASA Astrophysics Data System (ADS)

    Zeng, YuLang; Dong, Liang

    2015-01-01

    The outdoor thermal environment of a public space is highly relevant to the thermal perception of individuals, thereby affecting the use of space. This study aims to connect thermal human biometeorological conditions and subjective thermal sensation in hot and humid regions and to find its influence on street use. We performed a thermal comfort survey at three locations in a pedestrian precinct of Chengdu, China. Meteorological measurements and questionnaire surveys were used to assess the thermal sensation of respondents. The number of people visiting the streets was counted. Meanwhile, mean radiant temperature ( T mrt) and the physiological equivalent temperature (PET) index were used to evaluate the thermal environment. Analytical results reveal that weather and street design drive the trend of diurnal micrometeorological conditions of the street. With the same geometry and orientation, a street with no trees had wider ranges of meteorological parameters and a longer period of discomfort. The neutral temperature in Chengdu (24.4 °C PET) is similar to that in Taiwan, demonstrating substantial human tolerance to hot conditions in hot and humid regions. Visitors' thermal sensation votes showed the strongest positive relationships with air temperature. Overall comfort level was strongly related to every corresponding meteorological parameter, indicating the complexity of people's comfort in outdoor environments. In major alleys with multiple functions, the number of people in the street decreased as thermal indices increased; T mrt and PET had significant negative correlations with the number of people. This study aids in understanding pedestrian street use in hot and humid regions.

  14. Development of azimuthally correlated instabilities for MagLIF seeded by electro-thermal and material strength effects

    NASA Astrophysics Data System (ADS)

    Pecover, James; Weinwurm, Marcus; Chittenden, Jeremy

    2014-10-01

    Magnetized liner inertial fusion (MagLIF) is a promising route to controlled thermonuclear fusion. The concept involves magnetically imploding a metal liner; a key limitation of such systems is the magneto-Rayleigh-Taylor (MRT) instability. MagLIF relevant liner implosions carried out at Sandia showed high amplitude MRT growth. 3D simulations with our MHD code Gorgon have shown that azimuthal correlation required to explain this can be contributed to by early time effects the electro-thermal instability (ETI) and an ``electro-choric instability'' (ECI). Shear forces can damp short wavelength perturbations while the liner remains solid, potentially setting axial wavelengths for the ETI and ECI. We can now model shear stresses in solids with Gorgon using a Johnson-Cook strength model and a bulk modulus calculated from the FEOS equation of state. Gorgon results with the strength model are compared to results from the shock hydrodynamics code iSALE. Results for liners show elongation of perturbations at the outer edge relative to the case without strength. We present results showing the model applied to liner implosions with axial magnetic fields of 0 T and 10 T.

  15. Monitoring gold nanoparticle distribution with high resolution using photo-magnetic imaging

    NASA Astrophysics Data System (ADS)

    Luk, Alex T.; Nouizi, Farouk; Marks, Michael; Kart, Turkay; Gulsen, Gultekin

    2016-03-01

    One major advantage of using gold nanoparticles is the possibility of tuning their absorption peak by modifying their surface plasma resonance. They are proven to be a promising multi-functional platform that can be used for many imaging and therapeutic applications. As a true multi-modality imaging technique, Photo-Magnetic Imaging (PMI) has a great potential to monitor the distribution of gold nanoparticles non-invasively with MR resolution. With a simple addon of a continuous wave laser to an MRI system, PMI uses the laser induced temperature increase, measured by MR Thermometry (MRT), to provide tissue optical absorption maps at MR resolution. PMI utilizes a Finite Element Method (FEM) based algorithm to solve the combined diffusion and bio-heat equations. This system of combined equations models the photon distribution in the tissue and heat generation due to the absorption of the light and consequent heat diffusion. The key characteristic of PMI is that its spatial resolution is preserved at any depth as long as the temperature change within the imaged medium is detectable by MRT. Agar phantoms containing gold nanoparticles are used to validate the ability of PMI in monitoring their distribution. To make PMI suitable for diagnostic purposes, the laser powers has been kept under the American National Standard Institute maximum skin exposure limits in this study.

  16. Application of back-propagation artificial neural network and curve estimation in pharmacokinetics of losartan in rabbit

    PubMed Central

    Lin, Bin; Lin, Gaotong; Liu, Xianyun; Ma, Jianshe; Wang, Xianchuan; Lin, Feiyan; Hu, Lufeng

    2015-01-01

    In order to develop pharmacokinetic model, a well-known multilayer feed-forward algorithm back-propagation artificial neural networks (BP-ANN) was applied to the pharmacokinetics of losartan in rabbit. The plasma concentrations of losartan in twelve rabbits, which were divided into two groups and given losartan 2 mg/kg by intravenous (Iv) and intragastrical (Ig) administration, were determined by LC-MS. The BP-ANN model included one input layer, hidden layers, and one output layer was constructed and compared with curve estimation based on the time-concentration data of losartan. The results showed the BP-ANN model had high goodness of fit index and good coherence (R > 0.99) between forecasted concentration and measured concentration both in Iv and Ig administration. The residuals of each concentrations generated by BP-ANN model were all smaller than Curve estimation. The pharmacokinetic result showed there was no significant difference between measured and simulated pharmacokinetic parameters including AUC(0-t), AUC(0-∞), MRT(0-t), MRT(0-∞), T1/2 V and Cmax (P > 0.05). In conclusion, the BP-ANN model has remarkably accurate predictions ability, which better than Curve estimation, and can be used as a utility tool in pharmacokinetic experiment. PMID:26885213

  17. Growth and nitrogen use in Xanthium canadense grown in an open or in a dense stand.

    PubMed

    Watari, Ryoji; Nagashima, Hisae; Hirose, Tadaki

    2012-04-01

    Plants develop branches profusely when grown solitarily, while less so when grown in a dense stand. Such changes in architecture are associated with changes in dry mass allocation and nitrogen use. Here, we studied what traits in plant growth and nitrogen use were influenced by different light climates in the stand. Annual plants (Xanthium canadense) were grown solitarily or in a dense stand. Dry mass growth was analyzed as the product of the net assimilation rate (NAR) and leaf area (LA). Nitrogen use efficiency (NUE) was analyzed as the product of nitrogen productivity (NP) and the mean residence time (MRT) of nitrogen. These growth variables were further factorized into their components. Solitary plants maintained a high NAR, whereas plants in the dense stand decreased the NAR due to mutual shading. Plants in the dense stand developed a larger LA with a higher specific leaf area than solitary plants. Solitary plants had higher NUE due to higher NP. A temporal increase in NUE was attributed to the increase in MRT of nitrogen. Light climate was different between solitary and dense-stand plants, but they took up a comparable amount of nitrogen and used it differently in response to the given light climate. NUE was thus demonstrated to be a useful tool for analyzing the mechanism leading to different N use in plant growth.

  18. Seasonal recharge and mean residence times of soil and epikarst water in a small karst catchment of southwest China.

    PubMed

    Hu, Ke; Chen, Hongsong; Nie, Yunpeng; Wang, Kelin

    2015-01-01

    Soil and epikarst play an important role in the hydrological cycle in karst regions. This paper focuses on investigating the seasonal recharge and mean residence time (MRT) of soil water and epikarst water in a small karst catchment of southwest China. The deuterium contents in precipitation, creek, soil baseflow (direct recharge of the saturated soil water to the stream), epikarst spring, and soil waters were monitored weekly for two years, and MRT was calculated by an exponential model (EM) and a dispersion model (DM). The obvious seasonal variation of deuterium in rainfall was buffered in epikarst water, indicating sufficient water mixing. Soil baseflow contained less rainy-season rainwater than epikarst spring discharge, reflecting the retarded effect of soil thickness on rainwater recharge. MRTs of all water bodies were 41-71 weeks, and soils in the depression extended those of shallow groundwater. This demonstrated that the deep soil layer played an important role in karst hydrological processes in the study catchment. The creek was recharged mostly by rainfall through epikarst, indicating its crucial role in water circulation. These results showed epikarst had a strong water-holding capacity and also delayed water contact time with dolomite. PMID:25959092

  19. Short-term volcano-tectonic earthquake forecasts based on a moving mean recurrence time algorithm: the El Hierro seismo-volcanic crisis experience

    NASA Astrophysics Data System (ADS)

    García, Alicia; De la Cruz-Reyna, Servando; Marrero, José M.; Ortiz, Ramón

    2016-05-01

    Under certain conditions, volcano-tectonic (VT) earthquakes may pose significant hazards to people living in or near active volcanic regions, especially on volcanic islands; however, hazard arising from VT activity caused by localized volcanic sources is rarely addressed in the literature. The evolution of VT earthquakes resulting from a magmatic intrusion shows some orderly behaviour that may allow the occurrence and magnitude of major events to be forecast. Thus governmental decision makers can be supplied with warnings of the increased probability of larger-magnitude earthquakes on the short-term timescale. We present here a methodology for forecasting the occurrence of large-magnitude VT events during volcanic crises; it is based on a mean recurrence time (MRT) algorithm that translates the Gutenberg-Richter distribution parameter fluctuations into time windows of increased probability of a major VT earthquake. The MRT forecasting algorithm was developed after observing a repetitive pattern in the seismic swarm episodes occurring between July and November 2011 at El Hierro (Canary Islands). From then on, this methodology has been applied to the consecutive seismic crises registered at El Hierro, achieving a high success rate in the real-time forecasting, within 10-day time windows, of volcano-tectonic earthquakes.

  20. Interaction between affordance and handedness recognition: a chronometric study

    PubMed Central

    Lameira, A.P.; Pereira, A.; Conde, E.; Gawryszewski, L.G.

    2015-01-01

    The visualization of tools and manipulable objects activates motor-related areas in the cortex, facilitating possible actions toward them. This pattern of activity may underlie the phenomenon of object affordance. Some cortical motor neurons are also covertly activated during the recognition of body parts such as hands. One hypothesis is that different subpopulations of motor neurons in the frontal cortex are activated in each motor program; for example, canonical neurons in the premotor cortex are responsible for the affordance of visual objects, while mirror neurons support motor imagery triggered during handedness recognition. However, the question remains whether these subpopulations work independently. This hypothesis can be tested with a manual reaction time (MRT) task with a priming paradigm to evaluate whether the view of a manipulable object interferes with the motor imagery of the subject's hand. The MRT provides a measure of the course of information processing in the brain and allows indirect evaluation of cognitive processes. Our results suggest that canonical and mirror neurons work together to create a motor plan involving hand movements to facilitate successful object manipulation. PMID:25714894

  1. Thermal sintering: a novel technique used in the design, optimization and biopharmaceutical evaluation of propranolol HCl gastric floating tablets.

    PubMed

    Venkata Srikanth, Meka; Songa, Ambedkar Sunil; Nali, Sreenivasa Rao; Battu, Janaki Ram; Kolapalli, Venkata Ramana Murthy

    2014-01-01

    The objective of the present investigation was to study the applicability of thermal sintering technique for the development of gastric floating tablets of propranolol HCl. Formulations were prepared using four independent variables, namely (i) polymer quantity, (ii) sodium bicarbonate concentration, (iii) sintering temperature and (iv) sintering time. Floating lag time and t95 were taken as dependent variables. Tablets were prepared by the direct compression method and were evaluated for physicochemical properties, in vitro buoyancy and dissolution studies. From the drug release studies, it was observed that drug retarding property mainly depends upon the sintering temperature and time of exposure. The statistically optimized formulation (PTSso) was characterized by Fourier transform infrared spectroscopy and differential scanning calorimetry studies, and no significant chemical interaction between drug and polymer was observed. Optimized formulation was stable at accelerated conditions for a period of six months. PTSso was evaluated for in vivo buoyancy studies in humans for both fed and fasted states and found that gastric residence time of the floating tablets were enhanced by fed stage but not in fasted state. Optimized formulation PTSso and commercial formulation Ciplar LA 80 were subjected to bioavailability studies in healthy human volunteers by estimating pharmacokinetic parameters such as Cmax, Tmax, area under curve (AUC), elimination rate constant (Kel), biological half-life (t1/2) and mean residence time (MRT). There was a significant increase in the bioavailability of the propranolol HCl from PTSso formulation, which was evident from increased AUC levels and larger MRT values than Ciplar LA 80.

  2. The effects of meteorological factors on the occurrence of Ganoderma sp. spores in the air

    NASA Astrophysics Data System (ADS)

    Grinn-Gofroń, Agnieszka; Strzelczak, Agnieszka

    2011-03-01

    Ganoderma sp. is an airborne fungal spore type known to trigger respiratory allergy symptoms in sensitive patients. Aiming to reduce the risk for allergic individuals, we analysed fungal spore circulation in Szczecin, Poland, and its dependence on meteorological conditions. Statistical models for the airborne spore concentrations of Ganoderma sp.—one of the most abundant fungal taxa in the area—were developed. Aerobiological sampling was conducted over 2004-2008 using a volumetric Lanzoni trap. Simultaneously, the following meteorological parameters were recorded: daily level of precipitation, maximum and average wind speed, relative humidity and maximum, minimum, average and dew point temperatures. These data were used as the explaining variables. Due to the non-linearity and non-normality of the data set, the applied modelling techniques were artificial neural networks (ANN) and mutlivariate regression trees (MRT). The obtained classification and MRT models predicted threshold conditions above which Ganoderma sp. appeared in the air. It turned out that dew point temperature was the main factor influencing the presence or absence of Ganoderma sp. spores. Further analysis of spore seasons revealed that the airborne fungal spore concentration depended only slightly on meteorological factors.

  3. The (Re) Production of the Genetically Related Body in Law, Technology and Culture: Mitochondria Replacement Therapy.

    PubMed

    Griffiths, Danielle

    2016-09-01

    Advances in medicine in the latter half of the twentieth century have dramatically altered human bodies, expanding choices around what we do with them and how they connect to other bodies. Nowhere is this more so than in the area of reproductive technologies (RTs). Reproductive medicine and the laws surrounding it in the UK have reconfigured traditional boundaries surrounding parenthood and the family. Yet culture and regulation surrounding RTs have combined to try to ensure that while traditional boundaries may be pushed, they are reconstructed in similar ways. This paper looks at the most recent RT to be permitted in the UK, mitochondria (mtDNA) replacement therapy (MRT). Despite controversial media headlines surrounding the technique, MRT is in fact an example of how science and regulation seek to expand models of traditional relatedness in a way that doesn't challenge the existing order. Yet, like other RTs, while attempts are made to ensure it doesn't push traditional boundaries too far, fissures and inconsistencies appear in law and culture, which give interesting insights into how genetics, parentage and identity are being mediated in new but familiar ways. PMID:27453050

  4. Absorption and disposition of florfenicol after intravenous, intramuscular and subcutaneous dosing in alpacas.

    PubMed

    Pentecost, Rebecca L; Niehaus, Andrew J; Werle, Nicholas; Lakritz, Jeffrey

    2015-04-01

    The objectives of this study were to define disposition and systemic availability of florfenicol in alpacas. Administration of 20 mg/kg doses to 8 male alpacas by i.v., i.m. and s.c. routes was performed by randomized, 3-way crossover design. Clearance and steady state volumes (Vdss) after i.v. injection were 5 ml/min/kg and 775 ml/kg respectively. Mean residence time (MRT) and terminal phase half-life (T1/2λz) were 2.8 h and 2 h respectively. Maximum serum concentrations (Cmax) after i.m. were higher than s.c. administration (p = 0.034). After s.c. dosing, T1/2λz and MRT were greater than after i.m. injection (p < 0.001; p = 0.006 respectively). Mean absorption time (MAT) after s.c. dosing was also prolonged (p = 0.006). Fractional absorption of florfenicol after i.m. and s.c. was not different (p > 0.05). Serum florfenicol concentrations remained >1.0 µg/ml for 20 h after i.m. dosing. Differences in rate and extent of florfenicol absorption after extravascular dosing could influence therapeutic outcomes.

  5. Experimental Investigation of the Electrothermal Instability on Planar Foil Ablation Experiments

    NASA Astrophysics Data System (ADS)

    Steiner, Adam; Patel, Sonal; Yager-Elorriaga, David; Jordan, Nicholas; Gilgenbach, Ronald; Lau, Y. Y.

    2014-10-01

    The electrothermal instability (ETI) is an important early-time physical effect on pulsed power foil ablation experiments due to its ability to seed the destructive magneto-Rayleigh-Taylor (MRT) instability. ETI occurs whenever electrical resistivity has temperature dependence; when resistivity increases with temperature, as with solid metal liners or foils, ETI forms striation structures perpendicular to current flow. These striations provide an initial perturbation for the MRT instability, which is the dominant late-time instability in planar foil ablations. The MAIZE linear transformer driver was used to drive current pulses of approximately 600 kA into 400 nm-thick aluminum foils in order to study ETI in planar geometry. Shadowgraph images of the aluminum plasmas were taken for multiple shots at various times within approximately 50 ns of current start. Fourier analysis extracted the approximate wavelengths of the instability structures on the plasma-vacuum interface. Surface metrology of pre-shot foils was performed to provide a comparison between surface roughness features and resulting plasma structure. This work was supported by US DoE. S.G. Patel and A.M. Steiner supported by NPSC funded by Sandia. D.A. Yager supported by NSF fellowship Grant # DGE 1256260.

  6. New techniques for trapping antiprotons, positrons, and antihydrogen atoms

    SciTech Connect

    Yamazaki, Y.

    2005-10-26

    A large number of antiprotons have been accumulated, cooled, compressed, and extracted for the first time. This was accomplished combining the AD(Antiproton Decelerator), the RFQD (Radio Frequency Quadrupole Decelerator) and an MRT (Multi-Ring Trap) installed in a 2.5T solenoid. Some 1.2 x 106 antiprotons were stably stored per one AD shot, which was {approx}50 times better in the accumulation efficiency than conventional methods with thick degrader foils. The trapped antiprotons were then cooled by a preloaded electron plasma({approx} 108/cm3), radially compressed by a rotating electric field, and then extracted from the MRT as mono-energetic DC beams of 10-500eV. A similar system with much higher electron density({approx} 1011/cm3) has enabled a new positron accumulation, the efficiency of which is 360e+/s/mCi, some {approx}30 times better than previous UHV compatible schemes. With these ingredients, a cusp trap is under development, which could synthesize and at the same time trap spin-polarized antihydrogen atoms in their ground states.

  7. Effect of Crop cultivation after Mediterranean maquis on soil carbon stock, δ13C spatial distribution and root turnover

    NASA Astrophysics Data System (ADS)

    Novara, Agata; Gristina, Luciano; Santoro, Antonino; La Mantia, Tommaso

    2013-04-01

    The aim of this work was investigate the effect of land use change on soil organic carbon (SOC) stock and distribution in a Mediterranean succession. A succession composed by natural vegetation, cactus pear crop and olive grove, was selected in Sicily. The land use change from mediterranena maquis (C3 plant) to cactus pear (C4 plant) lead to a SOC decrease of 65% after 28 years of cultivation, and a further decrease of 14% after 7 years since the land use from cactus pear to olive grove (C3 plant). Considering this exchange and decrease as well as the periods after the land use changes we calculated the mean residence time (MRT) of soil C of different age. The MRT of C under Mediterranean maquis was about 142 years, but was 10 years under cactus pear. Total SOC and δ13 C were measured along the soil profile (0-75cm) and in the intra-rows in order to evaluate the distribution of new and old carbon derived and the growth of roots. After measuring of weight of cactus pear root, an approach was developed to estimate the turnover of root biomass. Knowledge of root turnover and carbon input are important to evaluate the correlation between carbon input accumulation and SOC stock in order to study the ability of C sink of soils with different use and managements.

  8. Dynamic T2-mapping during magnetic resonance guided high intensity focused ultrasound ablation of bone marrow

    NASA Astrophysics Data System (ADS)

    Waspe, Adam C.; Looi, Thomas; Mougenot, Charles; Amaral, Joao; Temple, Michael; Sivaloganathan, Siv; Drake, James M.

    2012-11-01

    Focal bone tumor treatments include amputation, limb-sparing surgical excision with bone reconstruction, and high-dose external-beam radiation therapy. Magnetic resonance guided high intensity focused ultrasound (MR-HIFU) is an effective non-invasive thermotherapy for palliative management of bone metastases pain. MR thermometry (MRT) measures the proton resonance frequency shift (PRFS) of water molecules and produces accurate (<1°C) and dynamic (<5s) thermal maps in soft tissues. PRFS-MRT is ineffective in fatty tissues such as yellow bone marrow and, since accurate temperature measurements are required in the bone to ensure adequate thermal dose, MR-HIFU is not indicated for primary bone tumor treatments. Magnetic relaxation times are sensitive to lipid temperature and we hypothesize that bone marrow temperature can be determined accurately by measuring changes in T2, since T2 increases linearly in fat during heating. T2-mapping using dual echo times during a dynamic turbo spin-echo pulse sequence enabled rapid measurement of T2. Calibration of T2-based thermal maps involved heating the marrow in a bovine femur and simultaneously measuring T2 and temperature with a thermocouple. A positive T2 temperature dependence in bone marrow of 20 ms/°C was observed. Dynamic T2-mapping should enable accurate temperature monitoring during MR-HIFU treatment of bone marrow and shows promise for improving the safety and reducing the invasiveness of pediatric bone tumor treatments.

  9. Building resilience.

    PubMed

    Seligman, Martin E P

    2011-04-01

    Failure is a familiar trauma in life, but its effects on people differ widely. Some reel, recover, and move on with their lives; others get bogged down by anxiety, depression, and fear of the future. Seligman, who is known as the father of positive psychology, has spent three decades researching failure, helplessness, and optimism. He created a program at the University of Pennsylvania to help young adults and children overcome anxiety and depression, and has worked with colleagues from around the world to develop a program for teaching resilience. That program is being tested by the U.S. Army, an organization of 1.1 million people where trauma is more common and more severe than in any corporate setting. Nevertheless, businesspeo-ple can draw lessons from resilience training, particularly in times of failure and stagnation. The program is called Comprehensive Soldier Fitness, and it has three components: the Global Assessment Tool, a test for psychological fitness (administered to more than 900,000 soldiers to date); self-improvement courses following the test; and "master resilience training" (MRT) for drill sergeants. MRT focuses on enhancing mental toughness, highlighting and honing strengths, and fostering strong relationships-core competencies for any successful manager.

  10. Exploration of MR-guided head and neck hyperthermia by phantom testing of a modified prototype applicator for use with proton resonance frequency shift thermometry.

    PubMed

    Numan, Wouter C M; Hofstetter, Lorne W; Kotek, Gyula; Bakker, Jurriaan F; Fiveland, Eric W; Houston, Gavin C; Kudielka, Guido; Yeo, Desmond T B; Paulides, Margarethus M

    2014-05-01

    Magnetic resonance thermometry (MRT) offers non-invasive temperature imaging and can greatly contribute to the effectiveness of head and neck hyperthermia. We therefore wish to redesign the HYPERcollar head and neck hyperthermia applicator for simultaneous radio frequency (RF) heating and magnetic resonance thermometry. In this work we tested the feasibility of this goal through an exploratory experiment, in which we used a minimally modified applicator prototype to heat a neck model phantom and used an MR scanner to measure its temperature distribution. We identified several distorting factors of our current applicator design and experimental methods to be addressed during development of a fully MR compatible applicator. To allow MR imaging of the electromagnetically shielded inside of the applicator, only the lower half of the HYPERcollar prototype was used. Two of its antennas radiated a microwave signal (150 W, 434 MHz) for 11 min into the phantom, creating a high gradient temperature profile (ΔTmax = 5.35 °C). Thermal distributions were measured sequentially, using drift corrected proton resonance frequency shift-based MRT. Measurement accuracy was assessed using optical probe thermometry and found to be about 0.4 °C (0.1-0.7 °C). Thermal distribution size and shape were verified by thermal simulations and found to have a good correlation (r(2 )= 0.76). PMID:24773040

  11. Advances in Computational Radiation Biophysics for Cancer Therapy: Simulating Nano-Scale Damage by Low-Energy Electrons

    NASA Astrophysics Data System (ADS)

    Kuncic, Zdenka

    Computational radiation biophysics is a rapidly growing area that is contributing, alongside new hardware technologies, to ongoing developments in cancer imaging and therapy. Recent advances in theoretical and computational modeling have enabled the simulation of discrete, event-by-event interactions of very low energy (≪ 100 eV) electrons with water in its liquid thermodynamic phase. This represents a significant advance in our ability to investigate the initial stages of radiation induced biological damage at the molecular level. Such studies are important for the development of novel cancer treatment strategies, an example of which is given by microbeam radiation therapy (MRT). Here, new results are shown demonstrating that when excitations and ionizations are resolved down to nano-scales, their distribution extends well outside the primary microbeam path, into regions that are not directly irradiated. This suggests that radiation dose alone is insufficient to fully quantify biological damage. These results also suggest that the radiation cross-fire may be an important clue to understanding the different observed responses of healthy cells and tumor cells to MRT.

  12. Manual landmark identification and tracking during the medial rotation test of the shoulder: an accuracy study using three-dimensional ultrasound and motion analysis measures.

    PubMed

    Morrissey, D; Morrissey, M C; Driver, W; King, J B; Woledge, R C

    2008-12-01

    Palpation of movement is a common clinical tool for assessment of movement in patients with musculoskeletal symptoms. The purpose of this study was to measure the accuracy of palpation of shoulder girdle translation during the medial rotation test (MRT) of the shoulder. The translation of the gleno-humeral and scapulo-thoracic joints was measured using both three-dimensional ultrasound and palpation in order to determine the accuracy of translation tracking during the MRT of the shoulder. Two movements of 11 normal subjects (mean age 24 (SD=4), range 19-47 years) were measured. The agreement between measures was good for scapulo-thoracic translation (r=0.83). Gleno-humeral translation was systematically under estimated (p=0.03) although moderate correlation was found (r=0.65). These results indicate that translation of the measured joints can be tracked by palpation and further tests of the efficacy of palpation tracking during musculoskeletal assessment may be warranted. PMID:18359266

  13. Seasonal recharge and mean residence times of soil and epikarst water in a small karst catchment of southwest China.

    PubMed

    Hu, Ke; Chen, Hongsong; Nie, Yunpeng; Wang, Kelin

    2015-05-11

    Soil and epikarst play an important role in the hydrological cycle in karst regions. This paper focuses on investigating the seasonal recharge and mean residence time (MRT) of soil water and epikarst water in a small karst catchment of southwest China. The deuterium contents in precipitation, creek, soil baseflow (direct recharge of the saturated soil water to the stream), epikarst spring, and soil waters were monitored weekly for two years, and MRT was calculated by an exponential model (EM) and a dispersion model (DM). The obvious seasonal variation of deuterium in rainfall was buffered in epikarst water, indicating sufficient water mixing. Soil baseflow contained less rainy-season rainwater than epikarst spring discharge, reflecting the retarded effect of soil thickness on rainwater recharge. MRTs of all water bodies were 41-71 weeks, and soils in the depression extended those of shallow groundwater. This demonstrated that the deep soil layer played an important role in karst hydrological processes in the study catchment. The creek was recharged mostly by rainfall through epikarst, indicating its crucial role in water circulation. These results showed epikarst had a strong water-holding capacity and also delayed water contact time with dolomite.

  14. Biologically effective dose in fractionated molecular radiotherapy—application to treatment of neuroblastoma with 131I-mIBG

    NASA Astrophysics Data System (ADS)

    Mínguez, Pablo; Gustafsson, Johan; Flux, Glenn; Sjögreen Gleisner, Katarina

    2016-03-01

    In this work, the biologically effective dose (BED) is investigated for fractionated molecular radiotherapy (MRT). A formula for the Lea-Catcheside G-factor is derived which takes the possibility of combinations of sub-lethal damage due to radiation from different administrations of activity into account. In contrast to the previous formula, the new G-factor has an explicit dependence on the time interval between administrations. The BED of tumour and liver is analysed in MRT of neuroblastoma with 131I-mIBG, following a common two-administration protocol with a mass-based activity prescription. A BED analysis is also made for modified schedules, when due to local regulations there is a maximum permitted activity for each administration. Modifications include both the simplistic approach of delivering this maximum permitted activity in each of the two administrations, and also the introduction of additional administrations while maintaining the protocol-prescribed total activity. For the cases studied with additional (i.e. more than two) administrations, BED of tumour and liver decreases at most 12% and 29%, respectively. The decrease in BED of the tumour is however modest compared to the two-administration schedule using the maximum permitted activity, where the decrease compared to the original schedule is 47%.

  15. Seasonal recharge and mean residence times of soil and epikarst water in a small karst catchment of southwest China

    NASA Astrophysics Data System (ADS)

    Hu, Ke; Chen, Hongsong; Nie, Yunpeng; Wang, Kelin

    2015-05-01

    Soil and epikarst play an important role in the hydrological cycle in karst regions. This paper focuses on investigating the seasonal recharge and mean residence time (MRT) of soil water and epikarst water in a small karst catchment of southwest China. The deuterium contents in precipitation, creek, soil baseflow (direct recharge of the saturated soil water to the stream), epikarst spring, and soil waters were monitored weekly for two years, and MRT was calculated by an exponential model (EM) and a dispersion model (DM). The obvious seasonal variation of deuterium in rainfall was buffered in epikarst water, indicating sufficient water mixing. Soil baseflow contained less rainy-season rainwater than epikarst spring discharge, reflecting the retarded effect of soil thickness on rainwater recharge. MRTs of all water bodies were 41-71 weeks, and soils in the depression extended those of shallow groundwater. This demonstrated that the deep soil layer played an important role in karst hydrological processes in the study catchment. The creek was recharged mostly by rainfall through epikarst, indicating its crucial role in water circulation. These results showed epikarst had a strong water-holding capacity and also delayed water contact time with dolomite.

  16. Does field independence predict visuo-spatial abilities underpinning human navigation? Behavioural evidence.

    PubMed

    Boccia, Maddalena; Piccardi, Laura; Di Marco, Mariangela; Pizzamiglio, Luigi; Guariglia, Cecilia

    2016-10-01

    Field independence (FI) has been defined as the extent to which the individual perceives part of a field as discrete from the surrounding field, rather than embedded in the field. It has been proposed to represent a relatively stable pattern in individuals' predisposition towards information processing. In the present study, we assessed the effect of FI on skills underpinning human navigation. Fifty Healthy individuals took part in this study. FI has been assessed by using the group embedded figures test (GEFT). Participants were also asked to perform several visuo-spatial orientation tasks, including the perspective taking/spatial orientation test (PTSOT), the mental rotation task (MRT) and the vividness task, as well as the Santa Barbara Sense of Direction Scale, a self-reported questionnaire, which has been found to predict environmental spatial orientation ability. We found that performances on the GEFT significantly predicted performances on the PTSOT and the MRT. This result supports the idea that FI predicts human navigation. PMID:27225254

  17. Verification of micro-beam irradiation

    NASA Astrophysics Data System (ADS)

    Li, Qiongge; Juang, Titania; Beth, Rachel; Chang, Sha; Oldham, Mark

    2015-01-01

    Micro-beam Radiation Therapy (MRT) is an experimental radiation therapy with provocative experimental data indicating potential for improved efficacy in some diseases. Here we demonstrated a comprehensive micro-beam verification method utilizing high resolution (50pm) PRESAGE/Micro-Optical-CT 3D Dosimetry. A small PRESAGE cylindrical dosimeter was irradiated by a novel compact Carbon-Nano-Tube (CNT) field emission based MRT system. The Percentage Depth Dose (PDD), Peak-to-Valley Dose Ratio (PVDR) and beam width (FWHM) data were obtained and analyzed from a three strips radiation experiment. A fast dose drop-off with depth, a preserved beam width with depth (an averaged FWHM across three beams remains constant (405.3um, sigma=13.2um) between depth of 3.0~14.0mm), and a high PVDR value (increases with depth from 6.3 at 3.0mm depth to 8.6 at 14.0mm depth) were discovered during this verification process. Some operating procedures such as precise dosimeter mounting, robust mechanical motions (especially rotation) and stray-light artifact management were optimized and developed to achieve a more accurate and dosimetric verification method.

  18. Segmental intelligibility of synthetic speech produced by rule.

    PubMed

    Logan, J S; Greene, B G; Pisoni, D B

    1989-08-01

    This paper reports the results of an investigation that employed the modified rhyme test (MRT) to measure the segmental intelligibility of synthetic speech generated automatically by rule. Synthetic speech produced by ten text-to-speech systems was studied and compared to natural speech. A variation of the standard MRT was also used to study the effects of response set size on perceptual confusions. Results indicated that the segmental intelligibility scores formed a continuum. Several systems displayed very high levels of performance that were close to or equal to scores obtained with natural speech; other systems displayed substantially worse performance compared to natural speech. The overall performance of the best system, DECtalk--Paul, was equivalent to the data obtained with natural speech for consonants in syllable-initial position. The findings from this study are discussed in terms of the use of a set of standardized procedures for measuring intelligibility of synthetic speech under controlled laboratory conditions. Recent work investigating the perception of synthetic speech under more severe conditions in which greater demands are made on the listener's processing resources is also considered. The wide range of intelligibility scores obtained in the present study demonstrates important differences in perception and suggests that not all synthetic speech is perceptually equivalent to the listener. PMID:2527884

  19. Pharmacokinetics of a new long acting endectocide formulation containing 2.25% ivermectin and 1.25% abamectin in cattle.

    PubMed

    Borges, F A; Cho, H S; Santos, E; Oliveira, G P; Costa, A J

    2007-02-01

    The objective of this study was to determine the kinetic parameters of a new formulation that contained 2.25% ivermectin combined with 1.25% abamectin in bovine plasma. The results for 2.25% ivermectin: Cmax (37.11 ng/mL +/- 7.42), Tmax (16 days +/- 5.29), T(1/2) (44.62 days +/- 53.89), AUC (928.2 ng x day/mL +/- 153.83) and MRT (36.73 days +/- 33.64), and for 1.25% abamectin: Cmax (28.70 ng/mL +/- 9.54), Tmax (14 days +/- 4.04), T(1/2) (15.40 days +/- 11.43), AUC (618.05 ng x day/mL +/- 80.27) and MRT (20.79 days +/- 8.43) suggest that this combination of 2.25% ivermectin + 1.25% abamectin possesses properties that give this pharmaceutical formula a longer activity time than two of the commercial products tested (1% ivermectin and 1% abamectin), and showed similarity to 3.15% ivermectin. PMID:17217403

  20. Seasonal recharge and mean residence times of soil and epikarst water in a small karst catchment of southwest China

    PubMed Central

    Hu, Ke; Chen, Hongsong; Nie, Yunpeng; Wang, Kelin

    2015-01-01

    Soil and epikarst play an important role in the hydrological cycle in karst regions. This paper focuses on investigating the seasonal recharge and mean residence time (MRT) of soil water and epikarst water in a small karst catchment of southwest China. The deuterium contents in precipitation, creek, soil baseflow (direct recharge of the saturated soil water to the stream), epikarst spring, and soil waters were monitored weekly for two years, and MRT was calculated by an exponential model (EM) and a dispersion model (DM). The obvious seasonal variation of deuterium in rainfall was buffered in epikarst water, indicating sufficient water mixing. Soil baseflow contained less rainy-season rainwater than epikarst spring discharge, reflecting the retarded effect of soil thickness on rainwater recharge. MRTs of all water bodies were 41-71 weeks, and soils in the depression extended those of shallow groundwater. This demonstrated that the deep soil layer played an important role in karst hydrological processes in the study catchment. The creek was recharged mostly by rainfall through epikarst, indicating its crucial role in water circulation. These results showed epikarst had a strong water-holding capacity and also delayed water contact time with dolomite. PMID:25959092

  1. Thin silicon strip detectors for beam monitoring in Micro-beam Radiation Therapy

    NASA Astrophysics Data System (ADS)

    Povoli, M.; Alagoz, E.; Bravin, A.; Cornelius, I.; Bräuer-Krisch, E.; Fournier, P.; Hansen, T. E.; Kok, A.; Lerch, M.; Monakhov, E.; Morse, J.; Petasecca, M.; Requardt, H.; Rosenfeld, A. B.; Röhrich, D.; Sandaker, H.; Salomé, M.; Stugu, B.

    2015-11-01

    Microbeam Radiation Therapy (MRT) is an emerging cancer treatment that is currently being developed at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. This technique uses a highly collimated and fractionated X-ray beam array with extremely high dose rate and very small divergence, to benefit from the dose-volume effect, thus sparing healthy tissue. In case of any beam anomalies and system malfunctions, special safety measures must be installed, such as an emergency safety shutter that requires continuous monitoring of the beam intensity profile. Within the 3DMiMic project, a novel silicon strip detector that can tackle the special features of MRT, such as the extremely high spatial resolution and dose rate, has been developed to be part of the safety shutter system. The first prototypes have been successfully fabricated, and experiments aimed to demonstrate their suitability for this unique application have been performed. Design, fabrication and the experimental results as well as any identified inadequacies for future optimisation are reported and discussed in this paper.

  2. Advances in Computational Radiation Biophysics for Cancer Therapy: Simulating Nano-Scale Damage by Low-Energy Electrons

    NASA Astrophysics Data System (ADS)

    Kuncic, Zdenka

    2015-10-01

    Computational radiation biophysics is a rapidly growing area that is contributing, alongside new hardware technologies, to ongoing developments in cancer imaging and therapy. Recent advances in theoretical and computational modeling have enabled the simulation of discrete, event-by-event interactions of very low energy (≪ 100 eV) electrons with water in its liquid thermodynamic phase. This represents a significant advance in our ability to investigate the initial stages of radiation induced biological damage at the molecular level. Such studies are important for the development of novel cancer treatment strategies, an example of which is given by microbeam radiation therapy (MRT). Here, new results are shown demonstrating that when excitations and ionizations are resolved down to nano-scales, their distribution extends well outside the primary microbeam path, into regions that are not directly irradiated. This suggests that radiation dose alone is insufficient to fully quantify biological damage. These results also suggest that the radiation cross-fire may be an important clue to understanding the different observed responses of healthy cells and tumor cells to MRT.

  3. Beryllium liner z-pinches for magneto-Rayleigh-Taylor studies on Z

    NASA Astrophysics Data System (ADS)

    McBride, R. D.; Slutz, S. A.; Sinars, D. B.; Lemke, R. W.; Martin, M. R.; Jennings, C. A.; Cuneo, M. E.; Herrmann, M. C.; Blue, B. E.

    2011-10-01

    Magnetized Liner Inertial Fusion (MagLIF) [S. A. Slutz, et al., Phys. Plasmas 17, 056303 (2010)] is a promising new concept for achieving >100 kJ of fusion yield on Z. The greatest threat to this concept is the magneto-Rayleigh-Taylor (MRT) instability. Thus experimental campaigns have been initiated to study MRT growth in fast imploding (<100 ns) cylindrical liners. This talk will present results from experiments that used 6.151-keV radiography to study the implosions of unperturbed (surface roughness only) beryllium (Be) liners. The high transmission efficiency of 6.151-keV photons through Be allowed us to obtain radiographs with finite transmission throughout the radial extent of the imploding liners. The data from these experiments will be shown and compared to simulation data from several magneto-hydrodynamic codes. These data are allowing us to evaluate the integrity of the inside (fuel-confining) surface of the imploding liner as it approaches stagnation. Sandia is a multi-program laboratory operated by Sandia Corp, a Lockheed-Martin company, for the US Dept of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  4. Cognitive functions in patients with liver cirrhosis: A tendency to commit more memory errors

    PubMed Central

    Ciećko-Michalska, Irena; Wójcik, Jan; Senderecka, Magdalena; Wyczesany, Mirosław; Binder, Marek; Szewczyk, Jakub; Dziedzic, Tomasz; Słowik, Agnieszka; Mach, Tomasz

    2013-01-01

    Background Minimal hepatic encephalopathy (MHE) is the mildest form of hepatic encephalopathy (HE). For diagnostic purposes, 2 alternative batteries of psychometric screening tests are recommended. They differ from each other in terms of the cognitive domains assessed. The research was designed to provide a profile of cognitive functioning in patients with liver cirrhosis, using an assessment that covers a wider range of cognitive functions than the usual screening battery. Material/Methods We examined 138 persons, including 88 with liver cirrhosis and 50 healthy volunteers. The Mini Mental State Examination (MMSE) was used for screening and excluding advanced cognitive impairment. Then, to assess cognitive functions in more detail, the following tests were used: Auditory Verbal Learning Test (AVLT), Letter and Semantic Fluency Tests (LF and SF), Trail Making Test (TMT A&B), Digit Symbol Test (DST), Block Design Test (BDT), and Mental Rotation Test (MRT). The MRT task has not been used in MHE diagnosis so far. Finally, 57 patients and 48 controls took part in the entire study. Results Patients with liver cirrhosis commit significantly more errors of intrusions in the AVLT during the delayed free recall trial. Results significantly deviating from the norm in at least 2 tests were found only in 7 cirrhosis patients. Conclusions The results do not provide any specific profile of cognitive disturbances in MHE, but suggest that cirrhosis patients have a tendency to commit more memory errors, probably due to subtle impairments of executive function. PMID:23598598

  5. The ethical challenges of the clinical introduction of mitochondrial replacement techniques.

    PubMed

    Appleby, John B

    2015-11-01

    Mitochondrial DNA (mtDNA) diseases are a group of neuromuscular diseases that often cause suffering and premature death. New mitochondrial replacement techniques (MRTs) may offer women with mtDNA diseases the opportunity to have healthy offspring to whom they are genetically related. MRTs will likely be ready to license for clinical use in the near future and a discussion of the ethics of the clinical introduction of MRTs is needed. This paper begins by evaluating three concerns about the safety of MRTs for clinical use on humans: (1) Is it ethical to use MRTs if safe alternatives exist? (2) Would persons with three genetic contributors be at risk of suffering? and (3) Can society trust that MRTs will be made available for humans only once adequate safety testing has taken place, and that MRTs will only be licensed for clinical use in a way that minimises risks? It is then argued that the ethics debate about MRTs should be reoriented towards recommending ways to reduce the possible risks of MRT use on humans. Two recommendations are made: (1) licensed clinical access to MRTs should only be granted to prospective parents if they intend to tell their children about their MRT conception by adulthood; and (2) sex selection should be used in conjunction with the clinical use of MRTs, in order to reduce transgenerational health risks. PMID:26239841

  6. The preclinical set-up at the ID17 biomedical beamline to achieve high local dose deposition using interlaced microbeams

    NASA Astrophysics Data System (ADS)

    Bräuer-Krisch, E.; Nemoz, C.; Brochard, Th; Berruyer, G.; Renier, M.; Pouyatos, B.; Serduc, R.

    2013-03-01

    Microbeam Radiation Therapy (MRT) uses spatially a fractionated "white beam" (energies 50-350 keV) irradiation from a Synchrotron Source. The typical microbeams used at ID17 are 25-100μm-thick, spaced by 200-400μm, and carry extremely high dose rates (up to about 16 kGy/s). These microbeams are well tolerated by biological tissue, i.e. up to several hundred of Gy in the peaks. When valley doses, caused by Compton scattering in between two microbeams, remain within a dose regime similar to conventional RT, a superior tumour control can be achieved with MRT than with conventional RT. The normal tissue tolerance of these microscopically small beams is outstanding and well documented in the literature. The hypothesis of a differential effect in particular on the vasculature of normal versus tumoral tissue might best be proven by using large animal models with spontaneous tumors instead of small laboratory animals with transplantable tumors, an ongoing project on ID17. An alternative approach to deposit a high dose, while preserving the feature of the spatial separation of these microbeams outside the target has opened up new applications in preclinical research. The instrumentation of this method to produce such interlaced beams is presented with an outlook on the challenges to build a treatment platform for human patients. Dose measurements using Gafchromic films exposed in interlaced geometries with their steep profiles highlight the potential to deposit radiotoxic doses in the vicinity of radiosensitive tissues.

  7. X-Tream: a novel dosimetry system for Synchrotron Microbeam Radiation Therapy

    NASA Astrophysics Data System (ADS)

    Petasecca, M.; Cullen, A.; Fuduli, I.; Espinoza, A.; Porumb, C.; Stanton, C.; Aldosari, A. H.; Bräuer-Krisch, E.; Requardt, H.; Bravin, A.; Perevertaylo, V.; Rosenfeld, A. B.; Lerch, M. L. F.

    2012-07-01

    Microbeam Radiation Therapy (MRT) is a radiation treatment technique under development for inoperable brain tumors. MRT is based on the use of a synchrotron generated X-ray beam with an extremely high dose rate ( ~ 20 kGy/sec), striated into an array of X-ray micro-blades. In order to advance to clinical trials, a real-time dosimeter with excellent spatial resolution must be developed for absolute dosimetry. The design of a real-time dosimeter for such a radiation scenario represents a significant challenge due to the high photon flux and vertically striated radiation field, leading to very steep lateral dose gradients. This article analyses the striated radiation field in the context of the requirements for temporal dosimetric measurements and presents the architecture of a new dosimetry system based on the use of silicon detectors and fast data acquisition electronic interface. The combined system demonstrates micrometer spatial resolution and microsecond real time readout with accurate sensitivity and linearity over five orders of magnitude of input signal. The system will therefore be suitable patient treatment plan verification and may also be expanded for in-vivo beam monitoring for patient safety during the treatment.

  8. Sex and cultural differences in spatial performance between Japanese and North Americans.

    PubMed

    Sakamoto, Maiko; Spiers, Mary V

    2014-04-01

    Previous studies have suggested that Asians perform better than North Americans on spatial tasks but show smaller sex differences. In this study, we evaluated the relationship between long-term experience with a pictorial written language and spatial performance. It was hypothesized that native Japanese Kanji (a complex pictorial written language) educated adults would show smaller sex differences on spatial tasks than Japanese Americans or North Americans without Kanji education. A total of 80 young healthy participants (20 native Japanese speakers, 20 Japanese Americans-non Japanese speaking, and 40 North Americans-non Japanese speaking) completed the Rey Complex Figure Test (RCFT), the Mental Rotations Test (MRT), and customized 2D and 3D spatial object location memory tests. As predicted, main effects revealed men performed better on the MRT and RCFT and women performed better on the spatial object location memory tests. Also, as predicted, native Japanese performed better on all tests than the other groups. In contrast to the other groups, native Japanese showed a decreased magnitude of sex differences on aspects of the RCFT (immediate and delayed recall) and no significant sex difference on the efficiency of the strategy used to copy and encode the RCFT figure. This study lends support to the idea that intensive experience over time with a pictorial written language (i.e., Japanese Kanji) may contribute to increased spatial performance on some spatial tasks as well as diminish sex differences in performance on tasks that most resemble Kanji.

  9. Interaction of rhubarb and methotrexate in rats: in vivo and ex vivo approaches.

    PubMed

    Shia, Chi-Sheng; Juang, Shin-Hun; Tsai, Shang-Yuan; Lee Chao, Pei-Dawn; Hou, Yu-Chi

    2013-01-01

    Rhubarb, the rhizome of Rheum palmatum L. (RP), is a popular herb used in Chinese medicine prescriptions. RP contains a variety of polyphenolic anthraquinones, such as aloe-emodin, rhein, emodin and chrysophanol. Our previous study found that the anthraquinones in RP existed predominantly as glucuronides/sulfates in the bloodstream, which were putative substrates of MRPs. Methotrexate (MTX) is a widely used immunosuppressant and anticancer agent, but it has a narrow therapeutic index. The transcellular transport of MTX is mediated by multidrug resistance associated proteins (MRPs). This study investigated the effects of coadministration of RP on MTX pharmacokinetics in rats. The possible involvement of MRP 2 was verified by using cell models and various typical MRP 2 substrates. The results showed that coadministration of 0.5 mg/kg of RP significantly increased the AUC 0-t and MRT of MTX by 307% and 364%, and 1.0 g/kg of RP significantly increased the AUC 0-t and MRT of MTX by 602% and 419%, respectively. Cell line studies indicated that the activity of MRP 2 was inhibited by the metabolites of RP and rhein. In conclusion, concomitant administration of RP markedly increased the systemic exposure of MTX via inhibiting MRP 2-mediated excretion.

  10. Investigation of Abscopal and Bystander Effects in Immunocompromised Mice After Exposure to Pencilbeam and Microbeam Synchrotron Radiation.

    PubMed

    Fernandez-Palomo, Cristian; Schültke, Elisabeth; Bräuer-Krisch, Elke; Laissue, Jean Albert; Blattmann, Hans; Seymour, Colin; Mothersill, Carmel

    2016-08-01

    Out-of-field effects are of considerable interest in radiotherapy. The mechanisms are poorly understood but are thought to involve signaling processes, which induce responses in non-targeted cells and tissues. The immune response is thought to play a role. The goal of this research was to study the induction of abscopal effects in the bladders of NU-Foxn1 mice after irradiating their brains using Pencil Beam (PB) or microbeam (MRT) irradiation at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. Athymic nude mice injected with F98 glioma cells into their right cerebral hemisphere 7 d earlier were treated with either MRT or PB. After recovery times of 2, 12, and 48 h, the urinary bladders were extracted and cultured as tissue explants for 24 h. The growth medium containing the potential signaling factors was harvested, filtered, and transferred to HaCaT reporter cells to assess their clonogenic survival and calcium signaling potential. The results show that in the tumor-free mice, both treatment modalities produce strong bystander/abscopal signals using the clonogenic reporter assay; however, the calcium data do not support a calcium channel mediated mechanism. The presence of a tumor reduces or reverses the effect. PB produced significantly stronger effects in the bladders of tumor-bearing animals. The authors conclude that immunocompromised mice produce signals, which can alter the response of unirradiated reporter cells; however, a novel mechanism appears to be involved. PMID:27356059

  11. Multiple-relaxation-time color-gradient lattice Boltzmann model for simulating two-phase flows with high density ratio.

    PubMed

    Ba, Yan; Liu, Haihu; Li, Qing; Kang, Qinjun; Sun, Jinju

    2016-08-01

    In this paper we propose a color-gradient lattice Boltzmann (LB) model for simulating two-phase flows with high density ratio and high Reynolds number. The model applies a multirelaxation-time (MRT) collision operator to enhance the stability of the simulation. A source term, which is derived by the Chapman-Enskog analysis, is added into the MRT LB equation so that the Navier-Stokes equations can be exactly recovered. Also, a form of the equilibrium density distribution function is used to simplify the source term. To validate the proposed model, steady flows of a static droplet and the layered channel flow are first simulated with density ratios up to 1000. Small values of spurious velocities and interfacial tension errors are found in the static droplet test, and improved profiles of velocity are obtained by the present model in simulating channel flows. Then, two cases of unsteady flows, Rayleigh-Taylor instability and droplet splashing on a thin film, are simulated. In the former case, the density ratio of 3 and Reynolds numbers of 256 and 2048 are considered. The interface shapes and spike and bubble positions are in good agreement with the results of previous studies. In the latter case, the droplet spreading radius is found to obey the power law proposed in previous studies for the density ratio of 100 and Reynolds number up to 500. PMID:27627415

  12. [Pliability and deflection of diagnostic catheters].

    PubMed

    Pelyhe, Liza; Bognár, Eszter

    2014-09-28

    Bevezetés: A szívkatéter olyan intravascularis katéter, amelyet a szívbe vezetnek vagy ültetnek be diagnosztikus vagy terápiás célból. A katéterek felvezetés/eltávolítás közben megtörhetnek vagy eltörhetnek. Célkitűzés: A szerzők két azonos alapanyagú, de különböző átmérőjű katéter hajlékonyságának meghatározását tűzték ki célul a Food and Drug Administration ajánlása alapján. Módszer: Meghatározták a hajlítási pontokat, a pontokon az átmérőcsökkenést, az elhajlás változását, továbbá e két paraméter csúcstól mért távolságának függését, korrelációjukat és a katéter kezdeti átmérőjének hatását. A katétereket 9-9 ponton (120–280 mm-re a páciensbe bevezetett végtől 20 mm-ként), 16 különböző sugarú idomszeren hajlították meg, amelyek sugara 10 mm-től 2,5 mm-ig 0,5 mm-ként csökkent. Eredmények: Megállapították, hogy az átmérőcsökkenés és az elhajlás lineárisan korrelál egymással, és függetlenek a mérési pont helyétől mindkét katéter esetében. A nagyobb átmérőjű katéternél szignifikánsan (p = 0,05) nagyobb volt az átmérőcsökkenés, mint a kisebbnél, de az átmérőcsökkenés és az elhajlási görbék lefutása hasonló. Következtetések: Az alkalmazott módszer alkalmasnak tűnik az adott típusú katéterek lehetséges gyenge pontjainak vizsgálatára. Orv. Hetil., 2014, 155(39), 1544–1548.

  13. Physiologically gated microbeam radiation using a field emission x-ray source array

    SciTech Connect

    Chtcheprov, Pavel E-mail: zhou@email.unc.edu; Burk, Laurel; Inscoe, Christina; Ger, Rachel; Hadsell, Michael; Lu, Jianping; Yuan, Hong; Zhang, Lei; Chang, Sha; Zhou, Otto E-mail: zhou@email.unc.edu

    2014-08-15

    Purpose: Microbeam radiation therapy (MRT) uses narrow planes of high dose radiation beams to treat cancerous tumors. This experimental therapy method based on synchrotron radiation has been shown to spare normal tissue at up to 1000 Gy of peak entrance dose while still being effective in tumor eradication and extending the lifetime of tumor-bearing small animal models. Motion during treatment can lead to significant movement of microbeam positions resulting in broader beam width and lower peak to valley dose ratio (PVDR), which reduces the effectiveness of MRT. Recently, the authors have demonstrated the feasibility of generating microbeam radiation for small animal treatment using a carbon nanotube (CNT) x-ray source array. The purpose of this study is to incorporate physiological gating to the CNT microbeam irradiator to minimize motion-induced microbeam blurring. Methods: The CNT field emission x-ray source array with a narrow line focal track was operated at 160 kVp. The x-ray radiation was collimated to a single 280 μm wide microbeam at entrance. The microbeam beam pattern was recorded using EBT2 Gafchromic{sup ©} films. For the feasibility study, a strip of EBT2 film was attached to an oscillating mechanical phantom mimicking mouse chest respiratory motion. The servo arm was put against a pressure sensor to monitor the motion. The film was irradiated with three microbeams under gated and nongated conditions and the full width at half maximums and PVDRs were compared. An in vivo study was also performed with adult male athymic mice. The liver was chosen as the target organ for proof of concept due to its large motion during respiration compared to other organs. The mouse was immobilized in a specialized mouse bed and anesthetized using isoflurane. A pressure sensor was attached to a mouse's chest to monitor its respiration. The output signal triggered the electron extraction voltage of the field emission source such that x-ray was generated only during a

  14. Tracer (18O, 3H, 3H/3He, CFC and SF6) and hydrochemistry to elucidate processes and mean residence times in porous aquifers in the South-East of Austria (Grazer and Leibnitzer Feld)

    NASA Astrophysics Data System (ADS)

    Kralik, M.; Humer, F.; Darling, G.; Sültenfuß, J.; Wyhlidal, S.

    2012-04-01

    The European Water Framework Directive requires the surface and groundwater bodies in the EU to be back to good quality conditions by 2015. To elucidate the mean residence time (MRT), the recharge area and the potential source of contaminations in particular monitoring wells a combination of several tracers has to be applied at least over one year to answer these questions with confidence. For the implementation of this goal it is necessary that any measures to improve groundwater quality show an impact depending on the MRT. The two groundwater bodies "Grazer Feld" and "Leibnitzer Feld" in the southern part of Styria, Austria stretch out along the river Mur in the N - S direction and covers an area of 166 and 103 km2. The porous aquifer of 10 - 20 m (Grazer Feld) of 6 - 10 m (Leibnitzer Feld) thickness consists of sandy gravel and boulders. In both groundwater bodies are about 2/3 of the aquifer is covered by loam of variable thickness. The depth to water varies between 2 - 20 and 2 - 8 m, respectively. The mean precipitation rate is 900 mm/a. The groundwater runs more or less along the river Mur with a small gradient. The northern part of the Grazer Feld groundwater body is dominated by the urban structure of the city of Graz. The southern part and the groundwater body Leibnitzer Feld is impacted intensively by agricultural use. Due to the extensive agricultural use it contains high concentrations of nitrate and pesticides and shows other hydrochemical changes caused by urbanisation and industrial use. In 33 monitoring wells delta oxygen-18 was analysed four times during one year within the framework of the Austrian hydrochemical groundwater monitoring system. During one campaign 3H, 3H/3He, CFCs and SF6 was analysed in all wells. In addition, the same methods were applied on depth-resolved groundwater samples at selected wells (Kralik et al. 2011). The results of the 3H-input and 3H/3He-models support in both groundwater bodies the rapid water circulation (<5

  15. Einleitung

    NASA Astrophysics Data System (ADS)

    Lange, Kurt

    Das Fließpressen zählt neben dem Stauchen und Gleitziehen zu den Kernverfahren des Kaltmassivumformens. In beschränktem Maße wird es auch im halbwarmen Bereich zwischen 600ºC und 800°C werkstoff- oder verfahrensbedingt angewandt. Besondere technisch-wirtschaftliche Bedeutung hat das Kaltfließpressen von Stahl erlangt, nachdem 1934 durch Phosphatieren der Rohteile nach dem Singer-Patent die sichere Umformung von Stahlwerkstoffen in Stahlwerkzeugen ohne Kaltverschweißen möglich geworden war. Die Werkstückmassen liegen beim Kaltfließpressen zwischen wenigen Gramm und einigen Kilogramm, seltener auch darüber. Grenzen sind die Werkzeugbelastung einerseits und die hohen Umformkräfte andererseits. Grundsätzlich lassen sich fast alle knetbaren Metalle durch Fließpressen umformen. Heute ist diese Verfahrensgruppe eine leistungsfähige Technologie, die die Fertigung präziser, geometrisch komplexer, hochbeanspruchbarer Werkstücke aus hochfesten Stählen für weite Einsatzbereiche mit geringstem Werkstoffeinsatz ermöglicht.

  16. [The mental health of only children and of siblings with cancer - first results of a multicenter study in Germany].

    PubMed

    Bojanowski, Sabine; Führer, Daniel; Romer, Georg; Bergelt, Corinna; von Klitzing, Kai; Brähler, Elmar; Keller, Monika; Resch, Franz; Flechtner, Hans-Henning; Lehmkuhl, Ulrike; Weschenfelder-Stachwitz, Heike

    2014-07-01

    Theoretischer Hintergrund: Kinder krebskranker Eltern wurden als Risikogruppe für die Entwicklung von psychischen Störungen identifiziert. Ergebnisse der Scheidungsforschung zeigten, dass auch Geschwisterbeziehungen bei belastenden Lebensereignissen vor psychischen Störungen schützen können. Fragestellung: Kann das Vorhandensein eines Geschwisters die Bewältigung einer elterlichen onkologischen Erkrankung unterstützen und somit auch dort als protektiver Faktor wirken? Methodik: In einer multizentrischen Studie wurden 271 Kinder untersucht. 54 % waren Inanspruchnehmer eines psychosozialen Beratungsangebotes. Einzelkinder (N = 89) und Kinder mit Geschwistern (N = 182) wurden im Hinblick auf ihre psychische Belastung (Strength and Difficulties Questionnaire, SDQ, Selbst- und Fremdurteil) miteinander verglichen. Ergebnisse: Im Gruppenvergleich zeigten sich zwischen Einzelkindern und Kindern mit Geschwistern keine signifikanten Unterschiede im Gesamturteil der Eltern. Dies galt sowohl für die Einschätzung durch den gesunden als auch durch den erkrankten Elternteil. In der Selbsteinschätzung zeigten sich bei 2 % der Einzelkinder und bei 9 % der Geschwister klinisch auffällige Werte im Gesamtproblemwert des SDQ. Der Gruppenvergleich zwischen Einzelkindern und Kindern mit Geschwistern offenbarte im Hinblick auf deren psychische Belastung keine bedeutsamen Unterschiede. Es ergaben sich Hinweise darauf, dass eine negative Beziehungsqualität (Sibling Relationship Questionnaire, SRQ) mit verstärkten Problemen in der Peer-Group assoziiert ist. Schlussfolgerungen: Das Vorhandensein eines Geschwisters ist nicht per se ein protektiver Faktor. Einzelkinder wiesen im Vergleich zu Kindern mit Geschwistern keine höhere psychische Belastung auf.

  17. Herschel und die Zukunft der Fern-Infrarot-Astronomie

    NASA Astrophysics Data System (ADS)

    Linz, Hendrik

    2015-06-01

    Schon lange ist die beobachtende Astronomie den engen Grenzen des optisch Sichbaren entwachsen und hat fast alle Bereiche des elektromagnetischen Spektrums für sich dienstbar gemacht. Im sogenannten nahen und mittleren Infrarot (Wellenlängen zwischen 1-30 μm) sowie im Millimeter- und Radio-Regime (Wellenlängen zwischen 1 mm und 10 m) ist die Erdatmosphäre relativ gut durchlässig für elektromagnetische Signale oder hat zumindest eine Vielzahl von spektral begrenzten Transmissionsfenstern, die astronomische Beobachtungen zumindest von höheren Bergen aus möglich machen. Allerdings ist das sogenannte Ferne Infrarot (FIR, 30-300 μm Wellenlänge) von der Erde aus fast völlig unzugänglich für astronomische Beobachtungen. Selbst für die besten Beobachtungsplätze der Erde bleibt die atmosphärische Transmission durch die immense Wasserdampf- Absorption auf ein absolutes Minimum beschränkt. Jedoch erlaubt uns das FIR Zugang zu Informationen, die sehr nützlich sind für die astrophysikalische Forschung und komplementär zu anderen Wellenlängen-Bereichen.

  18. Plasma and milk kinetics of eprinomectin following topical or oral administration to lactating Chinese Holstein cows.

    PubMed

    Wen, Huiqiang; Pan, Baoliang; Wang, Yuwan; Wang, Fangfei; Yang, Zhenzhong; Wang, Ming

    2010-11-24

    Chinese Holstein, bred by mating the Holstein-Friesian to Chinese Yellow Cattle, is a major dairy cattle breed in China. Eprinomectin is widely used in the treatment of nematode and ectoparasite infections in lactating cattle. The pharmacokinetics of eprinomectin in the plasma and milk were determined in Chinese Holstein cows following topical (at 0.5 mg kg(-1)) or oral (at 0.2 mg kg(-1)) administration. For topical administration, the concentrations of eprinomectin in plasma reached peak values (C(max)) of 16.16 ± 6.02 ng ml(-1) at 3.20 ± 1.30 days (T(max)). In milk, the C(max) values of 2.28 ± 0.85 ng ml(-1) were obtained at 3.48 ± 0.65 days. The MRT values were 5.00 ± 0.96 days for plasma and 4.65 ± 0.60 days for milk. The AUC values were 91.00 ± 25.32 ng d ml(-1) for plasma and 10.53 ± 1.55 ng d ml(-1) for milk. The ratio of AUC milk/plasma was 0.124 ± 0.041. Significant differences were found in C(max) and AUC of eprinomectin in plasma between Chinese Holstein and Prim Holstein following topical administration. It was probably due to the lower storage of body fat in Chinese Holstein than in Prim Holstein. For oral administration, the concentrations of eprinomectin reach peak values of 30.02 ± 5.73 ng ml(-1) at 1.60 ± 0.55 days in plasma and 3.14 ± 0.88 ng ml(-1) at 1.40 ± 0.27 days in milk. The MRT values for plasma and milk were 3.00 ± 0.46 and 3.18 ± 0.55 days, respectively. The AUC values were 98.46 ± 24.75 ng d ml(-1) for plasma and 10.42 ± 4.22 ng d ml(-1) for milk. The ratio of AUC milk/plasma was 0.104 ± 0.022. Compared with the topical administration, a significantly shorter MRT of eprinomectin in plasma was obtained following oral administration, which would shorten residue time of this compound in faeces and reduce its ecotoxicological effect. The low exposure of eprinomectin in milk would favor the use of eprinomectin in lactating Chinese Holstein for topical or oral administration. PMID:20851527

  19. In Situ Persistence and Migration of Biochar Carbon and Its Impact on Native Carbon Emission in Contrasting Soils under Managed Temperate Pastures.

    PubMed

    Singh, Bhupinder Pal; Fang, Yunying; Boersma, Mark; Collins, Damian; Van Zwieten, Lukas; Macdonald, Lynne M

    2015-01-01

    Pyrogenic carbon (PyC) is an important component of the global soil carbon (C) pool, but its fate, persistence, and loss dynamics in contrasting soils and environments under planted field conditions are poorly understood. To fill this knowledge gap, a 13C-labelled biochar, as a surrogate material for PyC, produced from Eucalyptus saligna by slow pyrolysis (450°C; δ13C -36.7‰) was surface (0-10 cm) applied in C3 dominated temperate pasture systems across Arenosol, Cambisol and Ferralsol. The results show a low proportion of the applied biochar-C mineralised over 12 months in a relatively clay- and C-poor Arenosol (i.e., 2.0% loss via mineralisation), followed by a clay- and C-rich Cambisol (4.6%), and clay-, C- and earthworm-rich Ferralsol (7.0%). The biochar-C mean residence time (MRT), estimated by different models, varied between 44-1079 (Arenosol), 18-172 (Cambisol), and 11-29 (Ferralsol) years, with the shorter MRT estimated by a one-pool exponential and the longer MRT by an infinite-pool power or a two-pool exponential model. The two-pool model was best fitted to biochar-C mineralisation. The biochar-C recovery in the 12-30 cm soil layer varied from between 1.2% (Arenosol), 2.5-2.7% (Cambisol) and 13.8-15.7% (Ferralsol) of the applied biochar-C after 8-12 months. There was a further migration of biochar-C below the 50-cm depth in the Arenosol, as the combined biochar-C recovery in the mineralised pool and soil profile (up to 30 or 50 cm) was 82%, in contrast to 101% in the Cambisol and 104% in the Ferralsol after 12 months. These results indicate that the downward migration of biochar-C was greatest in the Arenosol (cf. Cambisol and Ferralsol). Cumulative CO2-C emission from native soil-plant sources was lower (p <0.10) in the biochar-amended vs. non-amended Ferralsol. This field-based study shows that the downward migration of biochar-C exceeded its loss via mineralisation in the Arenosol and Ferralsol, but not in the Cambisol. It is thus important to

  20. Human Genome Replication Proceeds through Four Chromatin States

    PubMed Central

    Julienne, Hanna; Zoufir, Azedine; Audit, Benjamin; Arneodo, Alain

    2013-01-01

    Advances in genomic studies have led to significant progress in understanding the epigenetically controlled interplay between chromatin structure and nuclear functions. Epigenetic modifications were shown to play a key role in transcription regulation and genome activity during development and differentiation or in response to the environment. Paradoxically, the molecular mechanisms that regulate the initiation and the maintenance of the spatio-temporal replication program in higher eukaryotes, and in particular their links to epigenetic modifications, still remain elusive. By integrative analysis of the genome-wide distributions of thirteen epigenetic marks in the human cell line K562, at the 100 kb resolution of corresponding mean replication timing (MRT) data, we identify four major groups of chromatin marks with shared features. These states have different MRT, namely from early to late replicating, replication proceeds though a transcriptionally active euchromatin state (C1), a repressive type of chromatin (C2) associated with polycomb complexes, a silent state (C3) not enriched in any available marks, and a gene poor HP1-associated heterochromatin state (C4). When mapping these chromatin states inside the megabase-sized U-domains (U-shaped MRT profile) covering about 50% of the human genome, we reveal that the associated replication fork polarity gradient corresponds to a directional path across the four chromatin states, from C1 at U-domains borders followed by C2, C3 and C4 at centers. Analysis of the other genome half is consistent with early and late replication loci occurring in separate compartments, the former correspond to gene-rich, high-GC domains of intermingled chromatin states C1 and C2, whereas the latter correspond to gene-poor, low-GC domains of alternating chromatin states C3 and C4 or long C4 domains. This new segmentation sheds a new light on the epigenetic regulation of the spatio-temporal replication program in human and provides a

  1. Intake, ingesta retention, particle size distribution and digestibility in the hippopotamidae.

    PubMed

    Clauss, M; Schwarm, A; Ortmann, S; Alber, D; Flach, E J; Kühne, R; Hummel, J; Streich, W J; Hofer, H

    2004-12-01

    Although several aspects of the digestive physiology of the hippopotamidae-non-ruminating foregut fermenters-have been described, ingesta kinetics and passage characteristics of these species are not well understood. The most outstanding feature of the hippo digestive physiology reported so far is the very long mean ingesta retention times (MRTs) measured by Foose [Foose, T., 1982. Trophic strategies of ruminant versus nonruminant ungulates. PhD dissertation, University of Chicago, Chicago.]. Since those data had been investigated with animals without water access, we intended to measure MRT in hippos which were allowed to enter water pools during the night. MRT parameters as well as dry matter (DM) digestibility were determined in four common (Hippopotamus amphibius) and four pygmy hippos (Hexaprotodon liberiensis) on two different diets each using cobalt ethylendiamintetraacetate (Co-EDTA) as a fluid, chromium (Cr)-mordanted fibre (<2 mm) as a particle and acid detergent lignin (ADL) as an internal digestibility marker. Four of the animals additionally received cerium (Ce)-mordanted fibres (2-10 mm) as particle markers. Total MRTs for fluids and particles ranged between 20-35 and 48-106 h in the common and between 13-39 and 32-107 h in the pygmy hippos. The difference between fluid and particle retention was greater than usually reported in ruminants. Excretion patterns of the markers differed from those usually observed in ruminants but resembled those reported for macropods (kangaroos), indicating a plug-flow reactor-like physiology in the hippo forestomach (FRST). This finding complements other described similarities between the macropod and the hippo forestomach. The measurements of larger particle retention profiles suggest that in the hippo, larger particles might be excreted either faster or at the same rate as smaller particles, indicating a general difference between ruminants and hippos with respect to differential particle retention. The digestive

  2. The Morehead State University 18 Meter Radio Telescope Project: Involving Undergraduates in Observational Astrophysics

    NASA Astrophysics Data System (ADS)

    Malphrus, B. K.; Combs, M. S.; Kruth, J.

    2002-12-01

    The Space Science Center at Morehead State University is in the process of developing a large aperture (18-21 meter) cm-wave radio telescope, the Morehead Radio Telescope (MRT). The telescope will be located in the mountainous region of Eastern Kentucky. The instrument will serve as a research instrument and active laboratory for undergraduate astronomy, physics, pre-engineering, and computer science students. The antenna system will be engaged in science programs (in astrophysics) and in satellite mission support services (telemetry, tracking, and control). The benefits to students are based upon a hands-on approach to learning concepts in astrophysics and engineering. Additionally, there are still research contributions that small aperture centimeter-wave instruments can make including long-term observations of microvariability in AGNs, observations of transient events, and surveys. The MRT will operate three receiver systems including an L-band receiver (1.4-1.7 GHz) covering the "water hole", an S-band receiver (2.2-2.4 GHz) and a Ku-band receiver (11.2- 12.7 GHz) for continuum observations and satellite telemetry. The technical specifications for the instrument have been developed and an RFP has been issued inviting antenna vendors to submit proposals. The reflector will have a surface accuracy of 0.020 inches RMS over the entire surface, which will support relatively high frequency (Ku-band) observations. The antenna system will be full-motion and have a slew speed of 2 deg per second and an acceleration of 2 deg per second2. The HI and OH spatial distribution associated with cosmic phenomena will be investigated as well as dynamics and kinematics (particularly in HI) by observing over a range of frequencies (up to 2.5 MHz) with a 2048-channel back-end spectrometer, providing up to 1 KHz frequency resolution. The sensitivity and versatility of the telescope design will facilitate investigation of a wide variety of cosmic phenomena. The MRT is funded by

  3. The stability of Pyrogenic Organic Matter is dependent upon its wood source and charring temperature

    NASA Astrophysics Data System (ADS)

    Gibson, C. D.; Filley, T. R.; Bird, J.; Nadelhoffer, K. J.; Stark, R. E.; Hatton, P. J.

    2015-12-01

    Fire is a major mediator of carbon (C) cycling in forests and can result in the formation of pyrogenic organic matter (PyOM). The biological reactivity of PyOM is largely dependent upon the physiochemical characteristics of source material and production temperature. As a result, PyOM can persist up to centennial time scales after deposition while simultaneously enhancing or suppressing the mineralization of native soil C (NSC). To investigate the interactive effects of PyOM source and production temperature on NSC, we added 13C-enriched red maple (RM) or jack pine (JP) pyrolyzed at 200, 300, 450 or 600°C to a low C (0.5%;), near-surface soil (0-20 cm-depth) at 60% water holding capacity and 11% of native soil C and then incubated the samples in the dark at 25⁰C for 6 months. We found that PyOM mineralization rates decreased with increasing pyrolysis temperature for either species while NSC mineralization was suppressed across all treatments with the largest decrease observed in JP 300⁰C. RM mineralization rates were consistently greater (˜5 to ˜25%) than for JP <600⁰C during the first 17 days. Mean residence time (MRT) of PyOM-C was significantly higher in PyOM >300°C resulting in MRT of ~300 - 550 y compared to 8-30 y in lower temperature PyOM (0-300 °C). RM exhibited significantly lower MRT in 300°C PyOM than JP corresponding to differences observed in PyOM and NSC mineralization rates. The modelled active and slow pools of PyOM-C mineralized decreased with increasing combustion temperature. JP 300°C had a 20% smaller active pool when compared to RM suggesting that for both species, 300⁰C - 450⁰C represented a thermal transition point which was most evident in jack pine. These results highlight how differences in PyOM physiochemical characteristics linked to a species thermal transformation threshold may be a predictor in determining its biological reactivity in soil.

  4. Digestive physiology, metabolism and methane production of captive Linné's two-toed sloths (Choloepus didactylus).

    PubMed

    Vendl, C; Frei, S; Dittmann, M T; Furrer, S; Osmann, C; Ortmann, S; Munn, A; Kreuzer, M; Clauss, M

    2016-06-01

    Sloths are renowned for their low metabolic rate, low food intake and low defecation frequency. We investigated factors of digestive physiology and energy metabolism in four captive individuals (mean body mass 10.0 ± SD 3.7 kg) of a hitherto mostly unstudied sloth species, Linné's two-toed sloth (Choloepus didactylus), in a 2-week digestion recording and 23-h respiration experiment on animals fed a standard zoo diet of vegetables and starchy components. Dry matter intake, defecation frequency and particle mean retention time (MRT) in the gastrointestinal tract (GIT) were 12 ± 3 g/(kg(0.75)  day), once every 5 days and >140 h in three individuals, but 53 g/(kg(0.75)  day), daily and 82 h in one individual that was apparently compensating for a period of weight loss prior to the experiment. In all animals, solute marker was eliminated at a faster rate than the particle marker, indicating 'digesta washing' in the sloths' GIT. The overall metabolic rate calculated from oxygen consumption matched the metabolisable energy intake in three individuals [173 ± 22 vs. 168 ± 44 kJ/(kg(0.75)  day)] but not in the fourth one [225 vs. 698 kJ/(kg(0.75)  day)], supporting the interpretation that this animal was replenishing body stores. In spite of the low food intake and the low-fibre diet (209 ± 26 g neutral detergent fibre/kg dry matter), methane production was rather high accounting for 9.4 ± 0.8% of gross energy intake (2.7% in the fourth individual), which exceeded literature data for ruminants on forage-only diets. These results corroborate literature reports on low intake, low defecation frequency, low metabolic rate and long MRT in other sloth species. The long MRT is probably responsible for the comparatively high methane production, providing more opportunity for methanogenic archaea than in other non-ruminant mammals to produce significant amounts of methane.

  5. Variation in scorpion metabolic rate and rate-temperature relationships: implications for the fundamental equation of the metabolic theory of ecology.

    PubMed

    Terblanche, J S; Janion, C; Chown, S L

    2007-07-01

    The fundamental equation of the metabolic theory of ecology (MTE) indicates that most of the variation in metabolic rate are a consequence of variation in organismal size and environmental temperature. Although evolution is thought to minimize energy costs of nutrient transport, its effects on metabolic rate via adaptation, acclimatization or acclimation are considered small, and restricted mostly to variation in the scaling constant, b(0). This contrasts strongly with many conclusions of evolutionary physiology and life-history theory, making closer examination of the fundamental equation an important task for evolutionary biologists. Here we do so using scorpions as model organisms. First, we investigate the implications for the fundamental equation of metabolic rate variation and its temperature dependence in the scorpion Uroplectes carinatus following laboratory acclimation. During 22 days of acclimation at 25 degrees C metabolic rates declined significantly (from 127.4 to 78.2 microW; P = 0.0001) whereas mean body mass remained constant (367.9-369.1 mg; P = 0.999). In field-fresh scorpions, metabolic rate-temperature (MRT) relationships varied substantially within and among individuals, and therefore had low repeatability values (tau = 0.02) and no significant among-individual variation (P = 0.181). However, acclimation resulted in a decline in within-individual variation of MRT slopes which subsequently revealed significant differences among individuals (P = 0.0031) and resulted in a fourfold increase in repeatability values (tau = 0.08). These results highlight the fact that MRT relationships can show substantial, directional variation within individuals over time. Using a randomization model we demonstrate that the reduction in metabolic rate with acclimation while body mass remains constant causes a decline both in the value of the mass-scaling exponent and the coefficient of determination. Furthermore, interspecific comparisons of activation energy, E

  6. Modeling nonstructural carbohydrate reserve dynamics in forest trees

    NASA Astrophysics Data System (ADS)

    Richardson, A. D.; Keenan, T. F.; Carbone, M. S.; Czimczik, C. I.; Hollinger, D. Y.; Murakami, P.; Schaberg, P.; Xu, X.

    2012-12-01

    Understanding the factors influencing the availability of nonstructural carbohydrate (NSC) reserves is essential for predicting the resilience of forests to climate change and environmental stress. However, carbon allocation processes remain poorly understood and many models either ignore NSC reserves, or use simple and untested representations of NSC allocation and pool dynamics. Using model-data fusion techniques, we combined a parsimonious model of forest ecosystem carbon cycling with novel field sampling and laboratory analyses of NSCs. Simulations were conducted for an evergreen conifer forest and a deciduous broadleaf forest in New England. We used radiocarbon methods based on the 14C "bomb spike" to estimate the age of NSC reserves, and used this to constrain the mean residence time of modeled NSCs. We used additional data, including tower-measured fluxes of CO2, soil and biomass carbon stocks, woody biomass increment, and leaf area index and litterfall, to further constrain the model's parameters and initial conditions. Three years of field measurements indicate that stemwood NSCs are highly dynamic on seasonal time scales. The modeled seasonal dynamics conform to expectations (accumulated in the growing season, depleted in the dormant season) but are inconsistent with the observational data (total stemwood NSC concentrations higher in March than November, lower in August than June). We interpret this contradiction to suggest that stemwood concentrations provide an incomplete picture of the whole-tree NSC budget. A two-pool model structure that accounted for both "fast" (active pool, MRT ≈1 y) and "slow" (passive pool, MRT ≥ 20 y) cycling reserves (1) gives reasonable estimates of the size and MRT of the total NSC pool; (2) greatly improves model predictions of interannual variability in woody biomass increment, compared to zero- or one-pool structures used in the majority of existing models; (3) provides a mechanism by which observations of a one

  7. In Situ Persistence and Migration of Biochar Carbon and Its Impact on Native Carbon Emission in Contrasting Soils under Managed Temperate Pastures.

    PubMed

    Singh, Bhupinder Pal; Fang, Yunying; Boersma, Mark; Collins, Damian; Van Zwieten, Lukas; Macdonald, Lynne M

    2015-01-01

    Pyrogenic carbon (PyC) is an important component of the global soil carbon (C) pool, but its fate, persistence, and loss dynamics in contrasting soils and environments under planted field conditions are poorly understood. To fill this knowledge gap, a 13C-labelled biochar, as a surrogate material for PyC, produced from Eucalyptus saligna by slow pyrolysis (450°C; δ13C -36.7‰) was surface (0-10 cm) applied in C3 dominated temperate pasture systems across Arenosol, Cambisol and Ferralsol. The results show a low proportion of the applied biochar-C mineralised over 12 months in a relatively clay- and C-poor Arenosol (i.e., 2.0% loss via mineralisation), followed by a clay- and C-rich Cambisol (4.6%), and clay-, C- and earthworm-rich Ferralsol (7.0%). The biochar-C mean residence time (MRT), estimated by different models, varied between 44-1079 (Arenosol), 18-172 (Cambisol), and 11-29 (Ferralsol) years, with the shorter MRT estimated by a one-pool exponential and the longer MRT by an infinite-pool power or a two-pool exponential model. The two-pool model was best fitted to biochar-C mineralisation. The biochar-C recovery in the 12-30 cm soil layer varied from between 1.2% (Arenosol), 2.5-2.7% (Cambisol) and 13.8-15.7% (Ferralsol) of the applied biochar-C after 8-12 months. There was a further migration of biochar-C below the 50-cm depth in the Arenosol, as the combined biochar-C recovery in the mineralised pool and soil profile (up to 30 or 50 cm) was 82%, in contrast to 101% in the Cambisol and 104% in the Ferralsol after 12 months. These results indicate that the downward migration of biochar-C was greatest in the Arenosol (cf. Cambisol and Ferralsol). Cumulative CO2-C emission from native soil-plant sources was lower (p <0.10) in the biochar-amended vs. non-amended Ferralsol. This field-based study shows that the downward migration of biochar-C exceeded its loss via mineralisation in the Arenosol and Ferralsol, but not in the Cambisol. It is thus important to

  8. In Situ Persistence and Migration of Biochar Carbon and Its Impact on Native Carbon Emission in Contrasting Soils under Managed Temperate Pastures

    PubMed Central

    Singh, Bhupinder Pal; Fang, Yunying; Boersma, Mark; Collins, Damian; Van Zwieten, Lukas; Macdonald, Lynne M

    2015-01-01

    Pyrogenic carbon (PyC) is an important component of the global soil carbon (C) pool, but its fate, persistence, and loss dynamics in contrasting soils and environments under planted field conditions are poorly understood. To fill this knowledge gap, a 13C-labelled biochar, as a surrogate material for PyC, produced from Eucalyptus saligna by slow pyrolysis (450°C; δ13C -36.7‰) was surface (0−10 cm) applied in C3 dominated temperate pasture systems across Arenosol, Cambisol and Ferralsol. The results show a low proportion of the applied biochar-C mineralised over 12 months in a relatively clay- and C-poor Arenosol (i.e., 2.0% loss via mineralisation), followed by a clay- and C-rich Cambisol (4.6%), and clay-, C- and earthworm-rich Ferralsol (7.0%). The biochar-C mean residence time (MRT), estimated by different models, varied between 44−1079 (Arenosol), 18−172 (Cambisol), and 11−29 (Ferralsol) years, with the shorter MRT estimated by a one-pool exponential and the longer MRT by an infinite-pool power or a two-pool exponential model. The two-pool model was best fitted to biochar-C mineralisation. The biochar-C recovery in the 12−30 cm soil layer varied from between 1.2% (Arenosol), 2.5−2.7% (Cambisol) and 13.8−15.7% (Ferralsol) of the applied biochar-C after 8−12 months. There was a further migration of biochar-C below the 50-cm depth in the Arenosol, as the combined biochar-C recovery in the mineralised pool and soil profile (up to 30 or 50 cm) was 82%, in contrast to 101% in the Cambisol and 104% in the Ferralsol after 12 months. These results indicate that the downward migration of biochar-C was greatest in the Arenosol (cf. Cambisol and Ferralsol). Cumulative CO2-C emission from native soil-plant sources was lower (p <0.10) in the biochar-amended vs. non-amended Ferralsol. This field-based study shows that the downward migration of biochar-C exceeded its loss via mineralisation in the Arenosol and Ferralsol, but not in the Cambisol. It is thus

  9. In vitro-in vivo evaluation of in situ gelling and thermosensitive ketoprofen liquid suppositories.

    PubMed

    Ozgüney, Işık; Kardhiqi, Anita; Yıldız, Gülbeyaz; Ertan, Gökhan

    2014-12-01

    The main objective of this study was to investigate the release and pharmacokinetic profiles of ketoprofen (KP) from developed thermosensitive and mucoadhesive liquid suppositories. Thermosensitive liquid suppositories were prepared using KP, poloxamer 407 (P 407), poloxamer 188 (P 188) and various amounts of different mucoadhesive polymers. In vitro release studies was monitored by the USP XXVI paddle method. The results thus obtained were evaluated kinetically and mechanism of release was analyzed. Identification of poloxamer gel localization in vivo was conducted using white male rabbits by adding 1 % methylene blue. For in vivo studies, twenty-four white male rabbits were randomly divided into three groups. The rabbits in each group were administered with liquid suppository F1 [P407/P188/KP (4/20/2.5 %)], F5 [P407/P188/KP/C (4/20/2.5/0.8 %)] or conventional suppository (F-C) into the rectum. The plasma concentration of KP was analyzed by high performance liquid chromatography (HPLC). C max, AUC, MRT and T max were evaluated. The release of KP was variously affected by the mucoadhesive polymers. In vitro release studies showed that Carbopol 934 P(C) has significant effect on release rate among the mucoadhesive polymers. When the formulations were evaluated kinetically, different kinetic models were obtained. Formulation F6 [P407/P188/KP/C (4/20/2.5/1.6 %)] which contains the highest C concentration and very high viscosity, shows a significantly better fit with Higuchi kinetic model. n value of this formulation was also found approximately 0.5. n exponent results of the other formulations showed that KP might be released from the suppositories by non-Fickian diffusion. Identification of poloxamer gel localization in vivo showed that the suppositories remain in the rectum without leakage after administration. With regard to the results of in vivo studies, the AUC6→14 values of KP in liquid suppository containing C are significantly higher than those in

  10. Microbial carbon recycling: an underestimated process controlling soil carbon dynamics

    NASA Astrophysics Data System (ADS)

    Basler, A.; Dippold, M.; Helfrich, M.; Dyckmans, J.

    2015-07-01

    The mean residence times (MRT) of different compound classes of soil organic matter (SOM) do not match their inherent recalcitrance to decomposition. One reason for this is the stabilisation within the soil matrix, but recycling, i.e. the reuse of "old" organic material to form new biomass may also play a role as it uncouples the residence times of organic matter from the lifetime of discrete molecules in soil. We analysed soil sugar dynamics in a natural 30 years old labelling experiment after a~wheat-maize vegetation change to determine the extent of recycling and stabilisation in plant and microbial derived sugars: while plant derived sugars are only affected by stabilisation processes, microbial sugars may be subject to both, stabilisation and recycling. To disentangle the dynamics of soil sugars, we separated different density fractions (free particulate organic matter (fPOM), light occluded particulate organic matter (≤1.6 g cm-3; oPOM1.6), dense occluded particulate organic matter (≤2 g cm-3; oPOM2) and mineral-associated organic matter (>2 g cm-3; Mineral)) of a~silty loam under long term wheat and maize cultivation. The isotopic signature of sugars was measured by high pressure liquid chromatography coupled to isotope ratio mass spectrometry (HPLC/IRMS), after hydrolysis with 4 M Trifluoroacetic acid (TFA). While apparent mean residence times (MRT) of sugars were comparable to total organic carbon in the bulk soil and mineral fraction, the apparent MRT of sugars in the oPOM fractions were considerably lower than those of the total carbon of these fractions. This indicates that oPOM formation was fuelled by microbial activity feeding on new plant input. In the bulk soil, mean residence times of the mainly plant derived xylose (xyl) were significantly lower than those of mainly microbial derived sugars like galactose (gal), rhamnose (rha), fucose (fuc), indicating that recycling of organic matter is an important factor regulating organic matter dynamics

  11. Stabilization of glucose-C in microbial cell membranes (PLFA) and cell walls (amino sugars) evaluated by 13C-labelling in a field experiment

    NASA Astrophysics Data System (ADS)

    Gunina, Anna; Kuzyakov, Yakov; Glaser, Bruno

    2015-04-01

    Microorganisms control carbon (C) cycle and strongly contribute to formation of soil organic matter. Strong differences in the turnover of microbial groups and cellular compounds complicate the assessment of their contribution to microbial food webs and C sequestration in soil in situ. The uptake and incorporation of 13C labeled glucose by microbial groups were traced during 50 days after the labeling under field conditions. 13C was analysed: i) in the cytosolic pool by chloroform fumigation extraction, ii) in cell membranes by phospholipid fatty acids (PLFA), iii) in cell walls by amino sugars, and iv) remaining in bulk soil. This allowed tracing C in microbial groups as well as cellular compounds. Mean residence times (MRT) of C in PLFA and the cytosol were 47 and 150 days, respectively. Such long cytosol MRT depends on its heterogeneous composition, which includes high and low molecular weight organics. Amino sugars were mainly originated from microbial residues and thus, observation periods higher than 1 year are required for estimation of their MRT. Relative 13C incorporation (13C portion in total pool C) was the highest for PLFAs (~1.5% at day 3), whereas 13C content of the cytosol and amino sugars was one and two orders of magnitude less, respectively. Relative 13C incorporation into amino sugars of living microorganisms showed only 0.57% on day 3. Therefore, the turnover of cell membrane components is two times faster than that of cell walls, even in living microorganisms. Both PLFAs and amino sugars showed that glucose C was preferentially used by bacteria. 13C incorporation into bacterial cell walls and membranes decreased with time, but increased or remained constant for fungi, reflecting faster turnover of bacteria than fungi. Consequently, bacteria contribute more to the decomposition of low molecular weight organics, whereas fungi consume bacterial products or necromass and contribute more to long-term C stabilisation. Thus, tracing of 13C in cellular

  12. Methane emission, digestive characteristics and faecal archaeol in heifers fed diets based on silage from brown midrib maize as compared to conventional maize.

    PubMed

    Schwarm, Angela; Schweigel-Röntgen, Monika; Kreuzer, Michael; Ortmann, Sylvia; Gill, Fiona; Kuhla, Björn; Meyer, Ulrich; Lohölter, Malte; Derno, Michael

    2015-01-01

    The aim of the present experiment was to compare silage prepared from maize having a brown midrib (BMR) mutation with control (CTR) maize to identify their effects on enteric methane emission, digesta mean retention time (MRT), ruminal fermentation and digestibility. In addition, the utility of archaeol present in faecal samples was validated as a proxy for methane production. Seven German Holstein heifers were fed total mixed rations with a maize-silage proportion (either BMR or CTR) of 920 g/kg dry matter (DM) in a change-over design. Heifers were fed boluses with markers to measure MRT; faeces were collected for 7 days and rumen fluid was collected on the penultimate day. Methane emission was measured in respiration chambers on one day. Data were analysed by t-test and regression analysis. DM intake did not differ between the two diets. The apparent digestibility of DM and most nutrients was unaffected by diet type, but apparent digestibility of neutral and acid detergent-fibre was higher in those heifers fed BMR than in those fed CTR. Comparisons between diets revealed no difference in particle or solute MRT in the gastro-intestinal tract and the reticulorumen. Concentrations of short-chain fatty acid and ammonia in rumen fluid and its pH were not affected by silage type. Independent of the mode of expression [l/d, l/kg DM intake, l/kg digested organic matter], methane emissions were not affected by maize-silage type, but with BMR, there was a trend towards lower methane production per unit of digested neutral detergent fibre than there was with CTR silage. Results of the present study show that feeding heifers BMR silage does not increase methane emissions despite a higher fibre digestibility as compared to CTR silage. Therefore, it is assumed that improvements in animal productivity achieved by feeding BMR silage, as some studies have reported, can be obtained without extra environmental cost per unit of milk or meat. Neither faecal archaeol content [µg

  13. Nitrogen response efficiency increased monotonically with decreasing soil resource availability: a case study from a semiarid grassland in northern China.

    PubMed

    Yuan, Zhi-You; Li, Ling-Hao; Han, Xing-Guo; Chen, Shi-Ping; Wang, Zheng-Wen; Chen, Quan-Sheng; Bai, Wen-Ming

    2006-07-01

    The concept of nutrient use efficiency is central to understanding ecosystem functioning because it is the step in which plants can influence the return of nutrients to the soil pool and the quality of the litter. Theory suggests that nutrient efficiency increases unimodally with declining soil resources, but this has not been tested empirically for N and water in grassland ecosystems, where plant growth in these ecosystems is generally thought to be limited by soil N and moisture. In this paper, we tested the N uptake and the N use efficiency (NUE) of two Stipa species (S. grandis and S. krylovii) from 20 sites in the Inner Mongolia grassland by measuring the N content of net primary productivity (NPP). NUE is defined as the total net primary production per unit N absorbed. We further distinguished NUE from N response efficiency (NRE; production per unit N available). We found that NPP increased with soil N and water availability. Efficiency of whole-plant N use, uptake, and response increased monotonically with decreasing soil N and water, being higher on infertile (dry) habitats than on fertile (wet) habitats. We further considered NUE as the product of the N productivity (NP the rate of biomass increase per unit N in the plant) and the mean residence time (MRT; the ratio between the average N pool and the annual N uptake or loss). The NP and NUE of S. grandis growing usually in dry and N-poor habitats exceeded those of S. krylovii abundant in wet and N-rich habitats. NUE differed among sites, and was often affected by the evolutionary trade-off between NP and MRT, where plants and communities had adapted in a way to maximize either NP or MRT, but not both concurrently. Soil N availability and moisture influenced the community-level N uptake efficiency and ultimately the NRE, though the response to N was dependent on the plant community examined. These results show that soil N and water had exerted a great impact on the N efficiency in Stipa species. The

  14. Digestive physiology, metabolism and methane production of captive Linné's two-toed sloths (Choloepus didactylus).

    PubMed

    Vendl, C; Frei, S; Dittmann, M T; Furrer, S; Osmann, C; Ortmann, S; Munn, A; Kreuzer, M; Clauss, M

    2016-06-01

    Sloths are renowned for their low metabolic rate, low food intake and low defecation frequency. We investigated factors of digestive physiology and energy metabolism in four captive individuals (mean body mass 10.0 ± SD 3.7 kg) of a hitherto mostly unstudied sloth species, Linné's two-toed sloth (Choloepus didactylus), in a 2-week digestion recording and 23-h respiration experiment on animals fed a standard zoo diet of vegetables and starchy components. Dry matter intake, defecation frequency and particle mean retention time (MRT) in the gastrointestinal tract (GIT) were 12 ± 3 g/(kg(0.75)  day), once every 5 days and >140 h in three individuals, but 53 g/(kg(0.75)  day), daily and 82 h in one individual that was apparently compensating for a period of weight loss prior to the experiment. In all animals, solute marker was eliminated at a faster rate than the particle marker, indicating 'digesta washing' in the sloths' GIT. The overall metabolic rate calculated from oxygen consumption matched the metabolisable energy intake in three individuals [173 ± 22 vs. 168 ± 44 kJ/(kg(0.75)  day)] but not in the fourth one [225 vs. 698 kJ/(kg(0.75)  day)], supporting the interpretation that this animal was replenishing body stores. In spite of the low food intake and the low-fibre diet (209 ± 26 g neutral detergent fibre/kg dry matter), methane production was rather high accounting for 9.4 ± 0.8% of gross energy intake (2.7% in the fourth individual), which exceeded literature data for ruminants on forage-only diets. These results corroborate literature reports on low intake, low defecation frequency, low metabolic rate and long MRT in other sloth species. The long MRT is probably responsible for the comparatively high methane production, providing more opportunity for methanogenic archaea than in other non-ruminant mammals to produce significant amounts of methane. PMID:26122705

  15. Formal methods in the design of Ada 1995

    NASA Technical Reports Server (NTRS)

    Guaspari, David

    1995-01-01

    Formal, mathematical methods are most useful when applied early in the design and implementation of a software system--that, at least, is the familiar refrain. I will report on a modest effort to apply formal methods at the earliest possible stage, namely, in the design of the Ada 95 programming language itself. This talk is an 'experience report' that provides brief case studies illustrating the kinds of problems we worked on, how we approached them, and the extent (if any) to which the results proved useful. It also derives some lessons and suggestions for those undertaking future projects of this kind. Ada 95 is the first revision of the standard for the Ada programming language. The revision began in 1988, when the Ada Joint Programming Office first asked the Ada Board to recommend a plan for revising the Ada standard. The first step in the revision was to solicit criticisms of Ada 83. A set of requirements for the new language standard, based on those criticisms, was published in 1990. A small design team, the Mapping Revision Team (MRT), became exclusively responsible for revising the language standard to satisfy those requirements. The MRT, from Intermetrics, is led by S. Tucker Taft. The work of the MRT was regularly subject to independent review and criticism by a committee of distinguished Reviewers and by several advisory teams--for example, the two User/Implementor teams, each consisting of an industrial user (attempting to make significant use of the new language on a realistic application) and a compiler vendor (undertaking, experimentally, to modify its current implementation in order to provide the necessary new features). One novel decision established the Language Precision Team (LPT), which investigated language proposals from a mathematical point of view. The LPT applied formal mathematical analysis to help improve the design of Ada 95 (e.g., by clarifying the language proposals) and to help promote its acceptance (e.g., by identifying a

  16. Triglyceride to high density lipoprotein cholesterol ratio, total cholesterol to high density lipoprotein cholesterol ratio and low ankle brachial index in an elderly population.

    PubMed

    Zhan, Yiqiang; Yu, Jinming; Ding, Rongjing; Sun, Yihong; Hu, Dayi

    2014-05-01

    Hintergrund: Der Zusammenhang zwischen den Quotienten aus Triglycerid (TG) und High-density-lipoprotein-cholesterin (HDL‑C) sowie Gesamtcholesterin (TC) und HDL‑C und dem Knöchel-Arm-Index (ABI) wurde selten untersucht. Patienten und Methoden: Insgesamt 2.982 Teinehmer, die über 60 Jahre alt waren, wurden für die bevölkerungsbasierte Querschnittstudie rekrutiert. TG, TC, HDL‑C, und low-density Lipoprotein Cholesterol (LDL-C) wurden bei allen Teilnehmern getestet. Ein niedriger ABI wurde als ABI ≤ 0.9 definiert. Multiple Regressionsmodelle wurden für die Untersuchung der Assoziation zwischen TG/HDL‑C Ratio und TC/HDL‑C Ratio und niedrigem ABI angewendet. Ergebnisse: Die TG/HDL‑C Ratios für ABI > 0.9 und ABI ≤ 0.9 waren 1.28 ± 1.20 und 1.48 ± 1.13 (P < 0.0001), während die TC/HDL‑C Ratios 3.96 ± 1.09 bzw. 4.32 ± 1.15 (P < 0.0001) waren. Nach der Angleichung von Alter, Geschlecht, Body-Mass-Index, Fettleibigkeit, Alkoholkonsum, köperliche Aktivität, Hypertonie, Diabetes, Einnahme von lipidsenkenden Medikamenten, und Herz-Kreislauf-Erkrankungen waren die Odds Ratios (OR) mit 95 % Konfidenzintervall (KI) bei dem niedrigen ABI und TG/HDL‑C Quotient 1,10 (0,96 - 1,26) und 1,34 (1,14 - 1,59) für TC/HDL‑C in der Nichtrauchergruppe. Wenn das TC weiter angeglichen wurde, waren die ORs (95 % CIs) 1.40 (0.79, 2.52) und 1.53 (1.21, 1.93) für die TG/HDL‑C Ratio und TC/HDL‑C Ratio. Nichtlineare Zusammenhänge wurden zwischen der TG/HDL‑C Ratio und TC/HDL‑C Ratio und dem niedrigen ABI in der Raucher- und Nichtrauchergruppe entdeckt. Schlussfolgerungen: Die TC/HDL‑C Ratio war signifikant mit einem niedrigen ABI in der Nichtrauchergruppe verbunden und die Assoziation war unabhängig von TC, TG, HDL‑C und LDL-C. TC/HDL‑C könnte als potentieller Biomarker für die frühe periphere arterielle Verschlusskrankheit beim Screening berücksichtigt werden.

  17. FUNDAMENTAL AREAS OF PHENOMENOLOGY (INCLUDING APPLICATIONS): Lattice Boltzmann Simulation of the Cross Flow Over a Cantilevered and Longitudinally Vibrating Circular Cylinder

    NASA Astrophysics Data System (ADS)

    Xia, Yong; Lu, De-Tang; Liu, Yang; Xu, You-Sheng

    2009-03-01

    The multiple-relaxation-time lattice Boltzmann method (MRT-LBM) is implemented to numerically simulate the cross flow over a longitudinal vibrating circular cylinder. This research is carried out on a three-dimensional (3D) finite cantilevered cylinder to investigate the effect of forced vibration on the wake characteristics and the 3D effect of a cantilevered cylinder. To meet the accuracy of this method, the present calculation is carried out at a low Reynolds number Re = 100, as well as to make the vibration obvious, we make the vibration strong enough. The calculation results indicate that the vibration has significant influence on the wake characteristics. When the vibrating is big enough, our early works show that the 2D vortex shedding would be locked up by vibration. Contrarily, this phenomenon would not appear in the present 3D case because of the end effect of the cantilevered cylinder.

  18. Effects of noise and workload on a communication task

    NASA Astrophysics Data System (ADS)

    Orrell, D. H., II

    1985-05-01

    Communication is of vital importance in the cockpit today. It is essential for pilots to be able to understand the messages sent to them. A major requirement of any aircraft voice communication system is the ability to deliver intelligible speech. In a loose sense, intelligibility may be defined as the understanding of spoken words (Webster, 1979). Several language factors affect intelligibility including vocabulary size, word frequency (familiarity) effects, number of response alternatives, number of syllables, phonetic elements and context (Webster, 1972). Other external considerations include equipment or design features and environment (Webster and Allen, 1972). With such a wide range of sources of influence, it is easy to understand the need for a reliable intelligibility test. One such test found to be particularly useful in studying the effects of aircraft noise has been the Modified Rhyme Test (MRT).

  19. Analytical Method of Correction of B 1 Errors in Mapping of Magnetization Transfer Ratio in Highfield Magnetic Resonance Tomography

    NASA Astrophysics Data System (ADS)

    Yarnykh, V. L.; Khodanovich, M. Yu.

    2015-04-01

    Magnetization Transfer Ratio (MTR) is a widely used parameter for quantitative estimation of tissues in magnetic resonance tomography (MRT). At the same time, MTR is rather sensitive to errors caused by the nonideal characteristics of magnetic resonance tomographs. In particular, MTR depends strongly on the local inhomogeneities of the radio-frequency field B 1 that limits the MTR application for high magnetic field strengths. In the present research, a simple analytical model of the MTR dependence on B 1 is derived. Based on this model, a correction algorithm is developed using a set of parameters independent of tissue. This algorithm is tested for MTR mapping of the human brain in the field with induction of 3 T. The MTR correction demonstrates high accuracy for a wide range of B 1 inhomogeneities. Combination of the analytical algorithm with fast B 1 mapping enables high-precision MTR brain mapping for neuroimaging applications and analysis of histograms on high-field scanners.

  20. Numerical solution of optimal departure frequency of Taipei TMS

    NASA Astrophysics Data System (ADS)

    Young, Lih-jier; Chiu, Chin-Hsin

    2016-05-01

    Route Number 5 (Bannan Line) of Taipei Mass Rapid Transit (MRT) is the most popular line in the Taipei Metro System especially during rush hours periods. It has been estimated there are more than 8,000 passengers on the ticket platform during 18:00∼19:00 at Taipei main station. The purpose of this research is to predict a specific departure frequency of passengers per train. Monte Carlo Simulation will be used to optimize departure frequency according to the passenger information provided by 22 stations, i.e., 22 random variables of route number 5. It is worth mentioning that we used 30,000 iterations to get the different samples of the optimization departure frequency, i.e., 10 trains/hr which matches the practical situation.

  1. Integrated Program of Experimental Diagnostics at the NNSS. An Integrated, Prioritized Work Plan for Diagnostic Development and Maintenance and Supporting Capability

    SciTech Connect

    None, None

    2010-09-01

    This Integrated Program of Experimental Diagnostics at the NNSS is an integrated prioritized work plan for the Nevada National Security Site (NNSS), formerly the Nevada Test Site (NTS), program that is independent of individual National Security Enterprise Laboratories’ (Labs) requests or specific Subprograms being supported. This prioritized work plan is influenced by national priorities presented in the Predictive Capability Framework (PCF) and other strategy documents (Primary and Secondary Assessment Technologies Plans and the Plutonium Experiments Plan). This document satisfies completion criteria for FY 2010 MRT milestone #3496: Document an integrated, prioritized work plan for diagnostic development, maintenance, and supporting capability. This document is an update of the 3-year NNSS plan written a year ago, September 21, 2009, to define and understand Lab requests for diagnostic implementation. This plan is consistent with Lab interpretations of the PCF, Primary Assessment Technologies, and Plutonium Experiment plans.

  2. Automatische Lokalisation und hämodynamische Charakterisierung von Gefäßstrukturen bei arteriovenösen Malformationen

    NASA Astrophysics Data System (ADS)

    Forkert, Nils Daniel; Säring, Dennis; Fiehler, Jens; Illies, Till; Handels, Heinz

    Im Beitrag werden Verfahren zur automatischen Detektion des Kerns der Arteriovenösen Malformation (AVM) sowie der zuleitenden (Feeder), ableitenden (Drainagevenen) und en passge" Blutgef äße präsentiert. Als Eingabe hierfür dienen hochaufgelöste 3D- sowie zeitlich-räumliche 4D-MRT-Bildsequenzen. Durch eine kombinierte Analyse der Intensität, der Geschwindigkeit und des relativen Einflusszeitpunktes des Blutes werden Gefäßstrukturen automatisch charakterisiert. Die vorgestellte Methode zur Detektion des Kerns wurde anhand von manuellen Segmentierungen validiert und ergab eine mittlere Volumen- übereinstimmung von ca. 88%. Drainagevenen und Feeder konnten mit einer Genauigkeit von 95% detektiert werden.

  3. Nasal toxicity of cocaine: a hypercoagulable effect?

    PubMed Central

    Patel, R.; Shah, R.; Baredes, S.; Spillert, C. R.; Lazaro, E. J.

    2000-01-01

    Nasal insufflation of cocaine injures the nasal mucosa and can perforate the septum. Cocaine-induced vasoconstriction resulting in ischemia is one of the methods that may be responsible for this damage. We are determining whether cocaine also produces a hypercoagulable state that may compound factors which have been previously established to cause damage to the nasal mucosa and septum. This study uses Modified Recalcification Time (MRT), a test developed in our laboratory that has the ability to measure the overall coagulation process. Our study revealed no connection between cocaine and enhanced platelet function or monocyte-released tissue factor. The coagulation process was unaffected by the addition of the drug, so we conclude that cocaine does not cause a hypercoagulable state and cannot assist in the explanation regarding the ischemic changes of the nasal septum. PMID:10800286

  4. A review of imaging techniques for plant phenotyping.

    PubMed

    Li, Lei; Zhang, Qin; Huang, Danfeng

    2014-01-01

    Given the rapid development of plant genomic technologies, a lack of access to plant phenotyping capabilities limits our ability to dissect the genetics of quantitative traits. Effective, high-throughput phenotyping platforms have recently been developed to solve this problem. In high-throughput phenotyping platforms, a variety of imaging methodologies are being used to collect data for quantitative studies of complex traits related to the growth, yield and adaptation to biotic or abiotic stress (disease, insects, drought and salinity). These imaging techniques include visible imaging (machine vision), imaging spectroscopy (multispectral and hyperspectral remote sensing), thermal infrared imaging, fluorescence imaging, 3D imaging and tomographic imaging (MRT, PET and CT). This paper presents a brief review on these imaging techniques and their applications in plant phenotyping. The features used to apply these imaging techniques to plant phenotyping are described and discussed in this review. PMID:25347588

  5. Lattice Boltzmann Method for Spacecraft Propellant Slosh Simulation

    NASA Technical Reports Server (NTRS)

    Orr, Jeb S.; Powers, Joseph F.; Yang, Hong Q.

    2015-01-01

    A scalable computational approach to the simulation of propellant tank sloshing dynamics in microgravity is presented. In this work, we use the lattice Boltzmann equation (LBE) to approximate the behavior of two-phase, single-component isothermal flows at very low Bond numbers. Through the use of a non-ideal gas equation of state and a modified multiple relaxation time (MRT) collision operator, the proposed method can simulate thermodynamically consistent phase transitions at temperatures and density ratios consistent with typical spacecraft cryogenic propellants, for example, liquid oxygen. Determination of the tank forces and moments relies upon the global momentum conservation of the fluid domain, and a parametric wall wetting model allows tuning of the free surface contact angle. Development of the interface is implicit and no interface tracking approach is required. Numerical examples illustrate the method's application to predicting bulk fluid motion including lateral propellant slosh in low-g conditions.

  6. Lattice Boltzmann Method for Spacecraft Propellant Slosh Simulation

    NASA Technical Reports Server (NTRS)

    Orr, Jeb S.; Powers, Joseph F.; Yang, Hong Q

    2015-01-01

    A scalable computational approach to the simulation of propellant tank sloshing dynamics in microgravity is presented. In this work, we use the lattice Boltzmann equation (LBE) to approximate the behavior of two-phase, single-component isothermal flows at very low Bond numbers. Through the use of a non-ideal gas equation of state and a modified multiple relaxation time (MRT) collision operator, the proposed method can simulate thermodynamically consistent phase transitions at temperatures and density ratios consistent with typical spacecraft cryogenic propellants, for example, liquid oxygen. Determination of the tank forces and moments is based upon a novel approach that relies on the global momentum conservation of the closed fluid domain, and a parametric wall wetting model allows tuning of the free surface contact angle. Development of the interface is implicit and no interface tracking approach is required. A numerical example illustrates the method's application to prediction of bulk fluid behavior during a spacecraft ullage settling maneuver.

  7. Mitochondrial Replacement: Ethics and Identity

    PubMed Central

    Wilkinson, Stephen; Appleby, John B.

    2015-01-01

    Abstract Mitochondrial replacement techniques (MRTs) have the potential to allow prospective parents who are at risk of passing on debilitating or even life‐threatening mitochondrial disorders to have healthy children to whom they are genetically related. Ethical concerns have however been raised about these techniques. This article focuses on one aspect of the ethical debate, the question of whether there is any moral difference between the two types of MRT proposed: Pronuclear Transfer (PNT) and Maternal Spindle Transfer (MST). It examines how questions of identity impact on the ethical evaluation of each technique and argues that there is an important difference between the two. PNT, it is argued, is a form of therapy based on embryo modification while MST is, instead, an instance of selective reproduction. The article's main ethical conclusion is that, in some circumstances, there is a stronger obligation to use PNT than MST. PMID:26481204

  8. [Comparative efficiency of nootropic drugs in complex treatment of patients with remote consequences of closed craniocereberal trauma].

    PubMed

    Hliebova, O S; Tkachenko, O V

    2008-01-01

    Main data of the research were data obtained after a complex treatment of 120 persons with late consequences of closed craniocereberal trauma (CCRCT). The treatment included administration of one of nootropic agents (noophen, aminolon or entropil), magnesium sulfate, group B vitamins. All patients have passed a complex examination: specially developed questionnaire, anamnesis gathering, neurologic status, neuropsychological status with the use of multiple-aspect scales and questionnaires, examination of fundus of eye, rheoencephalography, echoencephalography, brain MRT. Results of a complex examination proved positive effect of the use of nootropic agents, in particular noophen, entropil and aminolon in complex treatment of late consequences of closed craniocereberal trauma. For optimisation of the use of nootropic agents in the treatment of late consequences of closed craniocereberal trauma it is recommended to consider features of influence of nootropic agents on certain clinical aspects of the disease.

  9. [Application of nootropic agents in complex treatment of patients with concussion of the brain].

    PubMed

    Tkachev, A V

    2007-01-01

    65 patients with a mild craniocereberal trauma have been observed. Medical examination included among general clinical methods the following methods: KT (MRT) of the brain, oculist examination including the observation of eye fundus. For objectification of a patient' complaints the authors used orientation and Galvestona's amnesia tests, feeling scale (psychological test), the table to determine the level of memory. Tests have been carried out on the first, tenth and thirty day of the treatment. Patients of the first group received in a complex treatment -pramistar, patients of the second group - piracetam. Patients of both groups noted considerable improvement during a complex treatment (disappearance of headache, dizziness and nausea) and at the same time patients receiving pramistar had better restoration of orientation and feeling. Pramistar was also more effective in patients with amnesia.

  10. Disposition of marbofloxacin in vulture (Gyps fulvus) after intravenous administration of a single dose.

    PubMed

    Garcia-Montijano, Marino; Waxman, Samanta; de Lucas, J Julio; Luaces, I; de San Andrés, María Dolores; Rodríguez, Casilda

    2011-04-01

    The pharmacokinetics properties of marbofloxacin were studied in adult Eurassian Griffon vulture after single-dose intravenous (IV) administration of 2mg/kg. Drug concentration in plasma was determined by high-performance liquid chromatography and the data obtained were subjected to compartmental and non-compartmental kinetic analysis. Marbofloxacin presented a volume of distribution at steady-state (Vdss) of 1.51±0.22L and total plasma clearance (Cl) of 0.109±0.023L/hkg. The permanence of this drug was long in vultures (T(1/2)(λ)=12.51±2.52h; MRT(∞)=13.54±2.29h). The optimal dose of marbofloxacin estimated is 2.73mg/kg per day for the treatment of infections in vultures with MIC(90)=0.2μg/mL.

  11. [Absolute bioavailability of the adenine derivative VMA-99-82 possessing antiviral activity].

    PubMed

    Smirnova, L A; Suchkov, E A; Riabukha, A F; Kuznetsov, K A; Ozerov, A A

    2013-01-01

    Investigation of the main pharmacokinetic parameters of adenine derivative VMA-99-82 in rats showed large values of the half-life (T1/2 = 11.03 h) and the mean retention time of drug molecules in the organism (MRT = 9.53 h). A high rate of the drug concentration decrease in the plasma determines a small value of the area under the pharmacokinetic curve (AUC = 74.96 mg h/ml). The total distribution volume (V(d) = 10.61 l/kg) is 15.8 times greater than the volume of extracellular fluid in the body of rat, which is indicative of a high ability of VMA-99-82 to be distributed and accumulated in the organs and tissues. The absolute bioavailability of VMA-99-82 is 66%. PMID:24605425

  12. The disposition of free and niosomally encapsulated Rac-flurbiprofen in dairy bovines.

    PubMed

    Confalonieri, E O; Soraci, A L; Becaluba, M; Denzoin, L; Rodriguez, E; Riccio, B; Tapia, O

    2010-02-01

    Pharmacokinetic parameters were established for flurbiprofen (FBP) after intravenous (i.v.) administration (0.5 mg/kg) of niosomal and nonniosomal formulations in dairy cattle. Niosomes of FBP showed a drug loading of 92.0 +/- 0.7% and the intravenous administration of the FBP niosomes to dairy cattle did not produce any immunological reaction associated to niosomal components. Niosomal FBP was slowly eliminated from plasma and mean residual time (MRT) and AUC(0-->t) and t (1/2) values were significantly higher than those for non niosomal FBP formulations. The results presented in this study indicate that the long circulation of FBP niosomes offers a potential application for improving the pharmacokinetic parameters of short half-life drugs for clinical use. Niosomes offer new promising perspectives of drug delivery modules in bovine therapeutics.

  13. [ABSOLUTE AND RELATIVE BIOAVAILABILITY OF GLUTARON--A NEW DERIVATIVE OF GLUTAMIC ACID].

    PubMed

    Smirnova, L A; Ryabukha, A F; Kuznetsov, K A; Suchkov, E A; Perfilova, V N; Tyurenkov, I N

    2015-01-01

    The pharmacokinetics of studies of 3-phenylglutamic acid hydrochloride (glutaron) has been studied in rats. The main pharmacokinetic parameters show low values of the half-life (T1/2 = 3.75 h), mean retention time in the body (MRT = 5.77 h). The medium rate of drug concentration decrease in the blood plasma leads to a low value of the area under pharmacokinetic curve (AUC = 41.18 mg · h/mL). The general volume of distribution (Vd = 3.42 L/kg) is 3.5 times greater than the volume of extracellular fluid in the rat body. These data indicate a high ability of the glutaron to be distributed and accumulated in animal tissues. The value of absolute bioavailability is 84%, and the relative bioavailabity is 100%.

  14. Characterization of a tungsten/gas multislit collimator for microbeam radiation therapy at the European Synchrotron Radiation Facility

    NASA Astrophysics Data System (ADS)

    Bräuer-Krisch, E.; Bravin, A.; Zhang, L.; Siegbahn, E.; Stepanek, J.; Blattmann, H.; Slatkin, D. N.; Gebbers, J.-O.; Jasmin, M.; Laissue, J. A.

    2005-06-01

    Clinical microbeam radiation therapy (MRT) will require a multislit collimator with adjustable uniform slit widths to enable reliable Monte Carlo-based treatment planning. Such a collimator has been designed, fabricated of >99% tungsten [W] by Tecomet/Viasys (Woburn, Massachusetts, USA) and installed at the 6GeV electron-wiggler-generated hard x-ray ID17 beamline of the European Synchrotron Radiation Facility. Its pair of 125 parallel, 8mm deep, 0.100mm wide radiolucent slits, 0.400mm on center, are perfused with nitrogen gas [N2] to dissipate heat during irradiation. Major improvements in uniformity of microbeam widths and good peak/valley dose ratios combined with a very high dose rate in targeted tissues have been achieved.

  15. Mechanisms Controlling Carbon Turnover from Diverse Microbial Groups in Temperate and Tropical Forest Soils

    NASA Astrophysics Data System (ADS)

    Throckmorton, H.; Dane, L.; Bird, J. A.; Firestone, M. K.; Horwath, W. R.

    2010-12-01

    Microorganisms represent an important intermediate along the pathway of plant litter decomposition to the formation of soil organic matter (SOM); yet little is known of the fate and stability of microbial C in soils and the importance of microbial biochemistry as a factor influencing SOM dynamics. This research investigates mechanisms controlling microbial C stabilization in a temperate forest in the Sierra Nevada of California (CA) and a tropical forest in Puerto Rico (PR). Biochemically diverse microbial groups (fungi, actinomycetes, bacteria gram (+), and bacteria gram (-)) were isolated from both sites, grown in the laboratory with C13 media, killed, and nonliving residues were added back to soils as a reciprocal transplant of microbial groups. The native microbial community in CA is dominated by fungi and in PR is dominated by bacteria, which provides an opportunity to asses the metabolic response of distinct microbial communities to the diverse microbial additions. CA and PR soils were sampled five times over a 3 and 2 year period, respectively. In CA there was no significant difference in the mean residence time (MRT) of diverse C13 microbial treatments; whereas in PR there were significant differences, whereby temperate fungi, temperate Gram (+) bacteria, and tropical actinomycetes exhibited a significantly longer MRT as compared with tropical fungi and temperate Gram (-). These results suggest that a bacterial dominated microbial community discriminates more amongst diverse substrates than a fungal-dominated community. MRT for labeled-C in CA was 5.21 ± 1.11 years, and in PR was 2.22 ± 0.45. Despite substantial differences in MRT between sites, physical fractionation of soils into light (LF), aggregated-occluded (OF), and mineral-associated (MF) fractions provided evidence that accelerated decomposition in PR (presumably due to climate) operated primarily on labeled-C unassociated with the mineral matrix (LF); labeled-C occluded within aggregates (OF) or

  16. Measurement Uncertainty Budget of the PMV Thermal Comfort Equation

    NASA Astrophysics Data System (ADS)

    Ekici, Can

    2016-05-01

    Fanger's predicted mean vote (PMV) equation is the result of the combined quantitative effects of the air temperature, mean radiant temperature, air velocity, humidity activity level and clothing thermal resistance. PMV is a mathematical model of thermal comfort which was developed by Fanger. The uncertainty budget of the PMV equation was developed according to GUM in this study. An example is given for the uncertainty model of PMV in the exemplification section of the study. Sensitivity coefficients were derived from the PMV equation. Uncertainty budgets can be seen in the tables. A mathematical model of the sensitivity coefficients of Ta, hc, T_{mrt}, T_{cl}, and Pa is given in this study. And the uncertainty budgets for hc, T_{cl}, and Pa are given in this study.

  17. Human safety and pharmacokinetics of the CFC alternative propellants HFC 134a (1,1,1,2-tetrafluoroethane) and HFC 227 (1,1,1,2,3,3, 3-heptafluoropropane) following whole-body exposure.

    PubMed

    Emmen, H H; Hoogendijk, E M; Klöpping-Ketelaars, W A; Muijser, H; Duistermaat, E; Ravensberg, J C; Alexander, D J; Borkhataria, D; Rusch, G M; Schmit, B

    2000-08-01

    /2)beta (beta elimination half-life) across all exposure concentrations was a mean of 36 and 42 min for CFC 12 and HFC 134a, respectively. Mean residence time (MRT) was an overall mean of 42 and 44 min for CFC 12 and HFC 134a, respectively. In the HFC 227 study, t(1/2)alpha for both CFC 12 and HFC 227, at each exposure level, was short (<9 min) and tended to be lower in males than females. For CFC 12 mean t(1/2)beta ranged from 23 to 43 min and for HFC 227 the mean range was 19-92 min. The values tended to be lower for females than males for HFC 227. For both CFC 12 and HFC 227, MRT was statistically significantly lower (P < 0.05) in males than females and independent of exposure concentration. For CFC 12, MRT was a mean of 37 and 45 min for males and females, respectively, and for HFC 227 MRT was a mean of 36 and 42 min, respectively. Exposure of healthy volunteers to exposure levels up to 8000 ppm HFC 134a, 8000 ppm HFC 227, and 4000 ppm CFC 12 did not result in any adverse effects on pulse, blood pressure, electrocardiogram, or lung function.

  18. Roof sprinkling system sweats down A/C costs

    SciTech Connect

    Not Available

    1984-05-01

    This article describes a roof spray system which enhances the energy efficiency of a building's HVAC system at a nominal cost in relationship to the benefits it yields. Roof spray cooling is based on the fact that water, when it evaporates, absorbs large amounts of heat. The evaporation of one gallon of water will dissipate about 8500 BTU's of heat; and three fallons of water evaporated over one hour's time offers the same cooling capacity as a two-ton airconditioner operated over the same period. By intermittently spraying its surface with water, a direct evaporative cooling system allows a roof to sweat away the sun's radiant heat, cooling an un-airconditioned building from 10 to 12 degrees mrt and reducing summer electric costs by 25%.

  19. Perception of synthetic speech produced automatically by rule: Intelligibility of eight text-to-speech systems.

    PubMed

    Greene, Beth G; Logan, John S; Pisoni, David B

    1986-03-01

    We present the results of studies designed to measure the segmental intelligibility of eight text-to-speech systems and a natural speech control, using the Modified Rhyme Test (MRT). Results indicated that the voices tested could be grouped into four categories: natural speech, high-quality synthetic speech, moderate-quality synthetic speech, and low-quality synthetic speech. The overall performance of the best synthesis system, DECtalk-Paul, was equivalent to natural speech only in terms of performance on initial consonants. The findings are discussed in terms of recent work investigating the perception of synthetic speech under more severe conditions. Suggestions for future research on improving the quality of synthetic speech are also considered. PMID:23225916

  20. Development of a single tube multiplex real-time PCR to detect the most clinically relevant Mucormycetes species.

    PubMed

    Bernal-Martínez, L; Buitrago, M J; Castelli, M V; Rodriguez-Tudela, J L; Cuenca-Estrella, M

    2013-01-01

    Mucormycetes infections are very difficult to treat and a delay in diagnosis could be fatal for the outcome of the patient. A molecular diagnostic technique based on Real Time PCR was developed for the simultaneous detection of Rhizopus oryzae, Rhizopus microsporus and the genus Mucor spp. in both culture and clinical samples. The methodology used was Molecular beacon species-specific probes with an internal control. This multiplex real-time PCR (MRT-PCR) was tested in 22 cultured strains and 12 clinical samples from patients suffering from a proven mucormycosis. Results showed 100% specificity and a detection limit of 1 fg of DNA per microlitre of sample. The sensitivity was 100% for clinical cultured strains and for clinical samples containing species detected by the PCR assay. Other mucormycetes species were not detected in clinical samples. This technique can be useful for clinical diagnosis and further studies are warranted.

  1. A peptide & peptide nucleic acid synthesis technology for transporter molecules and theranostics--the SPPS.

    PubMed

    Pipkorn, Ruediger; Braun, Klaus; Wiessler, Manfred; Waldeck, Waldemar; Schrenk, Hans-Hermann; Koch, Mario; Semmler, Wolfhard; Komljenovic, Dorde

    2014-01-01

    Advances in imaging diagnostics using magnetic resonance tomography (MRT), positron emission tomography (PET) and fluorescence imaging including near infrared (NIR) imaging methods are facilitated by constant improvement of the concepts of peptide synthesis. Feasible patient-specific theranostic platforms in the personalized medicine are particularly dependent on efficient and clinically applicable peptide constructs. The role of peptides in the interrelations between the structure and function of proteins is widely investigated, especially by using computer-assisted methods. Nowadays the solid phase synthesis (SPPS) chemistry emerges as a key technology and is considered as a promising methodology to design peptides for the investigation of molecular pharmacological processes at the transcriptional level. SPPS syntheses could be carried out in core facilities producing peptides for large-scale scientific implementations as presented here. PMID:24843319

  2. A Peptide & Peptide Nucleic Acid Synthesis Technology for Transporter Molecules and Theranostics - The SPPS

    PubMed Central

    Pipkorn, Ruediger; Braun, Klaus; Wiessler, Manfred; Waldeck, Waldemar; Schrenk, Hans-Hermann; Koch, Mario; Semmler, Wolfhard; Komljenovic, Dorde

    2014-01-01

    Advances in imaging diagnostics using magnetic resonance tomography (MRT), positron emission tomography (PET) and fluorescence imaging including near infrared (NIR) imaging methods are facilitated by constant improvement of the concepts of peptide synthesis. Feasible patient-specific theranostic platforms in the personalized medicine are particularly dependent on efficient and clinically applicable peptide constructs. The role of peptides in the interrelations between the structure and function of proteins is widely investigated, especially by using computer-assisted methods. Nowadays the solid phase synthesis (SPPS) chemistry emerges as a key technology and is considered as a promising methodology to design peptides for the investigation of molecular pharmacological processes at the transcriptional level. SPPS syntheses could be carried out in core facilities producing peptides for large-scale scientific implementations as presented here. PMID:24843319

  3. Sedimentological and geochronological evidences of anthropogenic impacts on river basins in the Northern Latium coastal area (Italy)

    NASA Astrophysics Data System (ADS)

    Piazzolla, Daniele; Paladini de Mendoza, Francesco; Scanu, Sergio; Marcelli, Marco

    2015-04-01

    In this work we aimed to compare sedimentological and geochronological data from three sediment core samples (MIG50, MRT50, and GRT50) taken in the Northern Latium (Italy) coastal area, at -50 m depth, to data regarding rainfall, river flows and the land use in the three most important hydrographic basins (Mignone, Marta and Fiora) and in the coastal area. Different trends of sediment mass accumulation rate (MAR) are detected in the three cores: a strongly increasing trend was identified in MIG50 and MRT50 cores while GRT50 doesn't show significant variation. Data from the sedimentological analysis of GRT50 core identify a progressive decrease in the sandy component, which declined from about 30% to the current level of 7% over the last 36 years, while MRT50 and MIG50 cores (mainly composed by pelitic fraction > 95%) showed slight variations of textural ratio between silt and clay. According to the general decrease of pluviometric trend observed in Italy, related to teleconnection pattern tendency (NAO), the statistical analysis of rain identified significative decrease only in the Fiora river basin, whereas in the other two locations the decrease was not as significant. Regarding the Fiora river flow, a significative decreasing trend of average flow is detected, while the flood regime remained unaffected over the past 30 years. The analysis of the land use shows that the human activities are increased of 6-10% over the available time steps (1990 - 2006) in Fiora and Mignone river basins, while the Marta river basin has a strong human impact since 1990 highligting more than 80% of artificial soil covering. The largest variation is observed on the Fiora basin (10%) where the antrhopic activities have expanded to an area of about 85 Km2. Moreover, in the last ten years a large beach nourishment in 2004 (570000 m3) and dredging activities in the early second half of 2000s (1000000 m3 moved) were performed in Marina di Tarquinia beach and in front of the Torrevaldaliga

  4. Lattice Boltzmann Simulation of Mixed Convection Heat Transfer in a Driven Cavity with Non-uniform Heating of the Bottom Wall

    NASA Astrophysics Data System (ADS)

    Soufiene, Bettaibi; Ezeddine, Sediki; Frédéric, Kuznik; Sauro, Succi

    2015-01-01

    The goal of this article is to study numerically the mixed convection in a differentially heated lid-driven cavity with non-uniform heating of the bottom wall. The velocity field is solved by a hybrid scheme with multiple relaxation time Lattice Boltzmann (MRT-LBM) model, while the temperature field is obtained by resolution of the energy balance equation using the finite difference method (FDM). First, the model is checked and validated using data from the literature. Validation of the present results with those available in the literature shows a good agreement. A good efficiency in time simulation is confirmed. Thereafter, the model has been applied to mixed convection in a driven cavity with non-uniform heating wall at the fixed Grashof number Gr = 106. It is found that, the heat transfer is weakened as the Richardson number is augmented. For Gr = 106, we note the appearance of secondary vortices at different positions of the cavity corners.

  5. Adaptation to Room Acoustics Using the Modified Rhyme Test

    PubMed Central

    Brandewie, Eugene; Zahorik, Pavel

    2012-01-01

    The negative effect of reverberant sound energy on speech intelligibility is well documented. Recently, however, prior exposure to room acoustics has been shown to increase intelligibility for a number of listeners in simulated room environments. This room adaptation effect, a possible extension of dynamic echo suppression, has been shown to be specific to reverberant rooms and requires binaural input. Because this effect has been demonstrated only using the Coordinated Response Measure (CRM) corpus it is important to determine whether the increase in intelligibility scores reported previously was due to the specific nature of the CRM task. Here we demonstrate a comparable room-acoustic effect using the Modified Rhyme Test (MRT) corpus in multiple room environments. The results are consistent with the idea that the room adaptation effect may be a natural phenomenon of listening in reverberant environments. PMID:23437415

  6. A Review of Imaging Techniques for Plant Phenotyping

    PubMed Central

    Li, Lei; Zhang, Qin; Huang, Danfeng

    2014-01-01

    Given the rapid development of plant genomic technologies, a lack of access to plant phenotyping capabilities limits our ability to dissect the genetics of quantitative traits. Effective, high-throughput phenotyping platforms have recently been developed to solve this problem. In high-throughput phenotyping platforms, a variety of imaging methodologies are being used to collect data for quantitative studies of complex traits related to the growth, yield and adaptation to biotic or abiotic stress (disease, insects, drought and salinity). These imaging techniques include visible imaging (machine vision), imaging spectroscopy (multispectral and hyperspectral remote sensing), thermal infrared imaging, fluorescence imaging, 3D imaging and tomographic imaging (MRT, PET and CT). This paper presents a brief review on these imaging techniques and their applications in plant phenotyping. The features used to apply these imaging techniques to plant phenotyping are described and discussed in this review. PMID:25347588

  7. A multiple relaxation time extension of the constant speed kinetic model

    NASA Astrophysics Data System (ADS)

    Zadehgol, Abed; Ashrafizaadeh, Mahmud

    2016-02-01

    In this work, a multiple relaxation time (MRT) extension of the recently introduced constant speed kinetic model (CSKM) is proposed. The CSKM, which is an entropic kinetic model and based on unconventional entropies of Burg and Tssalis, was introduced in [A. Zadehgol and M. Ashrafizaadeh, J. Comput. Phys. 274, 803 (2014)]; [A. Zadehgol Phys. Rev. E 91, 063311 (2015)] as an extension of the model of Boghosian et al. [Phys. Rev. E 68, 025103 (2003)] in the limit of fixed speed continuous velocities. The present extension improves the stability of the previous models at very high Reynolds numbers, while allowing for a more convenient orthogonal lattice. The model is verified by solving the following benchmark problems: (i) the lid driven square cavity and (ii) the Kelvin-Helmholtz instability of thin shear layers in a doubly periodic square domain.

  8. Radar and sensor netting - Present and future

    NASA Astrophysics Data System (ADS)

    Farina, A.; Studer, F. A.

    1986-01-01

    It is pointed out that a natural evolution of radar systems leads to the netting of radars dispersed on a certain portion of the surveillance space. The motivation for this evolution was provided by the possibility of fusing a great amount of data taken by radars operating independently. Multiradar tracking (MRT) represents a well-known system employed in civilian and military applications. The multistatic radar system is another well known netting concept. The present paper has the objective to provide some information regarding the potential of the netted system concepts. The netting of sensors other than radars is also promising, taking into account lasers, TV, radiometer, and acoustic devices. Attention is given to details concerning the multiradar system concept (the present), the multistatic system concept, wideband netting (the future), the multisensor system concept (the future), and artificial intelligence.

  9. Screening-induced carrier transport in silicene.

    PubMed

    Hu, Bo

    2015-06-24

    Based on the Boltzmann transport equation in the MRT approximation, we present a theory to investigate low-field carrier transport in dual-gated silicene FETs by taking into account screened charged impurity scattering, which is the most likely scattering mechanism limiting the conductivity. Static RPA dielectric screening is also included in the conductivity calculation to study temperature-dependent silicene transport. It is found that both calculated conductivity and band gap not only depend strongly on carrier sheet density, but also depend strongly on effective offset density. More importantly, screening-induced metal-insulator-transition phenomena in buckled silicene can be observed theoretically, which is similar to that obtained in monolayer graphene.

  10. Modulating mitochondrial quality in disease transmission: towards enabling mitochondrial DNA disease carriers to have healthy children.

    PubMed

    Diot, Alan; Dombi, Eszter; Lodge, Tiffany; Liao, Chunyan; Morten, Karl; Carver, Janet; Wells, Dagan; Child, Tim; Johnston, Iain G; Williams, Suzannah; Poulton, Joanna

    2016-08-15

    One in 400 people has a maternally inherited mutation in mtDNA potentially causing incurable disease. In so-called heteroplasmic disease, mutant and normal mtDNA co-exist in the cells of carrier women. Disease severity depends on the proportion of inherited abnormal mtDNA molecules. Families who have had a child die of severe, maternally inherited mtDNA disease need reliable information on the risk of recurrence in future pregnancies. However, prenatal diagnosis and even estimates of risk are fraught with uncertainty because of the complex and stochastic dynamics of heteroplasmy. These complications include an mtDNA bottleneck, whereby hard-to-predict fluctuations in the proportions of mutant and normal mtDNA may arise between generations. In 'mitochondrial replacement therapy' (MRT), damaged mitochondria are replaced with healthy ones in early human development, using nuclear transfer. We are developing non-invasive alternatives, notably activating autophagy, a cellular quality control mechanism, in which damaged cellular components are engulfed by autophagosomes. This approach could be used in combination with MRT or with the regular management, pre-implantation genetic diagnosis (PGD). Mathematical theory, supported by recent experiments, suggests that this strategy may be fruitful in controlling heteroplasmy. Using mice that are transgenic for fluorescent LC3 (the hallmark of autophagy) we quantified autophagosomes in cleavage stage embryos. We confirmed that the autophagosome count peaks in four-cell embryos and this correlates with a drop in the mtDNA content of the whole embryo. This suggests removal by mitophagy (mitochondria-specific autophagy). We suggest that modulating heteroplasmy by activating mitophagy may be a useful complement to mitochondrial replacement therapy. PMID:27528757

  11. Filter-matrix lattice Boltzmann model for incompressible thermal flows.

    PubMed

    Zhuo, Congshan; Zhong, Chengwen; Cao, Jun

    2012-04-01

    In this study, a new filter-matrix lattice Boltzmann (FMLB) model is proposed and extended to include incompressible thermal flows. A new equilibrium solution is found in the improved FMLB model, which is derived from the Hermite expansion. As a result, the velocity-dependent pressure is removed, which is an inherent defect of Somers's FMLB model. In addition, the improved model is extended to include incompressible thermal flows by introducing a class of temperature-distribution function for evaluating the temperature field. Two different temperature-distribution functions are discussed. The improved FMLB model and the temperature-evaluation equation are combined into one coupled model. Numerical simulations are performed on the two-dimensional (2D) lid-driven square cavity flow and the 2D natural convection flow in a square cavity using the improved FMLB model and the two coupled models, respectively. The numerical results of the 2D lid-driven square cavity flow show that the improved FMLB model is superior to the lattice Bhatnagar-Gross-Krook (LBGK) model in terms of both accuracy and stability. When compared with the multi-relaxation-time (MRT) model, the similar accuracy and slightly enhanced stability can be obtained by the improved model. The advantage of the improved model is that it no longer relies on difficult selection of the free parameters requested by the MRT model; in addition, the force term is already included in the collision operator of the improved model. In the case of 2D natural convection flow, the numerical results of the two present models are almost the same, and both exhibit good agreement with the benchmark solution.

  12. Filter-matrix lattice Boltzmann model for incompressible thermal flows

    NASA Astrophysics Data System (ADS)

    Zhuo, Congshan; Zhong, Chengwen; Cao, Jun

    2012-04-01

    In this study, a new filter-matrix lattice Boltzmann (FMLB) model is proposed and extended to include incompressible thermal flows. A new equilibrium solution is found in the improved FMLB model, which is derived from the Hermite expansion. As a result, the velocity-dependent pressure is removed, which is an inherent defect of Somers's FMLB model. In addition, the improved model is extended to include incompressible thermal flows by introducing a class of temperature-distribution function for evaluating the temperature field. Two different temperature-distribution functions are discussed. The improved FMLB model and the temperature-evaluation equation are combined into one coupled model. Numerical simulations are performed on the two-dimensional (2D) lid-driven square cavity flow and the 2D natural convection flow in a square cavity using the improved FMLB model and the two coupled models, respectively. The numerical results of the 2D lid-driven square cavity flow show that the improved FMLB model is superior to the lattice Bhatnagar-Gross-Krook (LBGK) model in terms of both accuracy and stability. When compared with the multi-relaxation-time (MRT) model, the similar accuracy and slightly enhanced stability can be obtained by the improved model. The advantage of the improved model is that it no longer relies on difficult selection of the free parameters requested by the MRT model; in addition, the force term is already included in the collision operator of the improved model. In the case of 2D natural convection flow, the numerical results of the two present models are almost the same, and both exhibit good agreement with the benchmark solution.

  13. An event-related analysis of P300 by simultaneous EEG/fMRI

    NASA Astrophysics Data System (ADS)

    Wang, Li-qun; Wang, Mingshi; Mizuhara, Hiroaki

    2006-09-01

    In this study, P300 that induced by visual stimuli was examined with simultaneous EEG/fMRI. For the purpose of combine the best temporary resolution with the best special resolution together to estimate the brain function, event-related analysis contributed to this methodological trial. A 64 channel MRT-compatible MR EEG amplifier (BrainAmp: made of Brain Production GmbH, Gennany) was used in the measurement simultaneously with fMRI scanning. The reference channel is between Fz, Cz and Pz. Sampling rate of raw EEG was 5 kHz, and the MRT noise reduction was performed. EEG recording synchronized with MRI scan by our original stimulus system, and an oddball paradigm (four-oriented Landolt Ring presentation) was performed in the official manner. After P300 segmentation, the timing of P300 was exported to event-related analysis of fMRI data with SPM99 software. In single subject study, the significant activations appear in the left superior frontal, Broca's area and on both sides of the parietal lobule when P300 occurred. It is suggest that P300 may be an integration carried out by top-down signal from frontal to the parietal lobule, which regulates an Attention-Logical Judgment process. Compared with other current methods, the event related analysis by simultaneous EEG/IMRI is excellent in the point that can describe the cognitive process with reality unifying further temporary and spatial information. It is expected that examination and demonstration of the obtained result will supply with the promotion of this powerful methods.

  14. MODIS Data and Services at the National Snow and Ice Data Center (NSIDC)

    NASA Astrophysics Data System (ADS)

    McAllister, M.; Booker, L.; Fowler, D. K.; Haran, T. M.

    2014-12-01

    For close to 15 years, the National Snow and Ice Data Center (NSIDC) NASA Distributed Active Archive Center (NDAAC) has archived and distributed snow and sea ice products derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on the NASA Earth Observing System (EOS) Aqua and Terra satellites. The archive contains a wide selection of snow and sea ice data products relevant to cryospheric science. NSIDC offers a variety of methods for obtaining these data. Users can ftp data directly from an online archive which allows for a very quick download. The Reverb Search & Order Tool contains a complete set of metadata for all products which can be searched for and ordered. Reverb allows a user to order spatial, temporal, and parameter subsets of the data. Users can also request that they be added to our subscription list which makes it possible to have new MODIS data automatically ftp'd or staged on a local server as it is archived at NSIDC. Since MODIS products are in HDF-EOS format, a number of tools have been developed to assist with browsing, editing, reprojection, resampling, and format conversion. One such service, Data Access, can be accessed through Reverb and performs subsetting, reformatting, and reprojection. This service can also be accessed via an Application Programming Interface (API) from a user-written client. Other tools include the MODIS Swath-to-Grid Toolbox (MS2GT) and the MODIS Interactive Subsetting Tool (MIST). MS2GT was created to produce a seamless output grid from multiple input files corresponding to successively acquired, 5-minute MODIS scenes. NSIDC also created the MIST to provide subsets of certain Version 5 MODIS products, over the Greenland Climate Network (GC-Net) and the International Arctic Systems for Observing the Atmosphere (IASOA) stations. Tools from other sources include HDFView from the National Center for Supercomputing Applications (NCSA), and the MODIS Reprojection Tool (MRT) and MRT Swath developed

  15. Genetics of Bladder Malignant Tumors in Childhood.

    PubMed

    Zangari, Andrea; Zaini, Johan; Gulìa, Caterina

    2016-02-01

    Bladder masses are represented by either benign or malignant entities. Malignant bladder tumors are frequent causes of disease and death in western countries. However, in children they are less common. Additionally, different features are found in childhood, in which non epithelial tumors are more common than epithelial ones. Rhabdomyosarcoma is the most common pediatric bladder tumor, but many other types of lesions may be found, such as malignant rhabdoid tumor (MRT), inflammatory myofibroblastic tumor and neuroblastoma. Other rarer tumors described in literature include urothelial carcinoma and other epithelial neoplasms. Rhabdomyosarcoma is associated to a variety of genetic syndromes and many genes are involved in tumor development. PAX3-FKHR and PAX7-FKHR (P-F) fusion state has important implications in the pathogenesis and biology of RMS, and different genes alterations are involved in the pathogenesis of P-F negative and embryonal RMS, which are the subsets of tumors most frequently affecting the bladder. These genes include p53, MEF2, MYOG, Ptch1, Gli1, Gli3, Myf5, MyoD1, NF1, NRAS, KRAS, HRAS, FGFR4, PIK3CA, CTNNB1, FBXW7, IGF1R, PDGFRA, ERBB2/4, MET, BCOR. Malignant rhabdoid tumor (MRT) usually shows SMARCB1/INI1 alterations. Anaplastic lymphoma kinase (ALK) gene translocations are the most frequently associated alterations in inflammatory myofibroblastic tumor (IMT). Few genes alterations in urothelial neoplasms have been reported in the paediatric population, which are mainly related to deletion of p16/lnk4, overexpression of CK20 and overexpression of p53. Here, we reviewed available literature to identify genes associated to bladder malignancies in children and discussed their possible relationships with these tumors. PMID:27013922

  16. Microbeam Radiation Therapy: Tissue Dose Penetration and BANG-Gel Dosimetry of Thick-Beams' Array Intelacing

    SciTech Connect

    Dilmanian, F.; Romanelli, P; Zhong, Z; Wang, R; Wagshul, M; Kalef-Ezra, J; Maryanski, M; Rosen, E; Anschel, D

    2008-01-01

    The tissue-sparing effect of parallel, thin (narrower than 100em) synchrotron-generated X-ray planar beams (microbeams) in healthy tissues including the central nervous system (CNS) is known since early 1990s. This, together with a remarkable preferential tumoricidal effect of such beam arrays observed at high doses, has been the basis for labeling the method microbeam radiation therapy (MRT). Recent studies showed that beams as thick as 0.68mm ('thick microbeams') retain part of their sparing effect in the rat's CNS, and that two such orthogonal microbeams arrays can be interlaced to produce an unsegmented field at the target, thus producing focal targeting. We measured the half-value layer (HVL) of our 120-keV median-energy beam in water phantoms, and we irradiated stereotactically bis acrylamide nitrogen gelatin (BANG)-gel-filled phantoms, including one containing a human skull, with interlaced microbeams and imaged them with MRI. A 43-mm water HVL resulted, together with an adequately large peak-to-valley ratio of the microbeams' three-dimensional dose distribution in the vicinity of the 20mmx20mmx20mm target deep into the skull. Furthermore, the 80-20% dose falloff was a fraction of a millimeter as predicted by Monte Carlo simulations. We conclude that clinical MRT will benefit from the use of higher beam energies than those used here, although the current energy could serve certain neurosurgical applications. Furthermore, thick microbeams particularly when interlaced present some advantages over thin microbeams in that they allow the use of higher beam energies and they could conceivably be implemented with high power orthovoltage X-ray tubes.

  17. Image-guided microbeam irradiation to brain tumour bearing mice using a carbon nanotube x-ray source array

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Yuan, Hong; Burk, Laurel M.; Inscoe, Christy R.; Hadsell, Michael J.; Chtcheprov, Pavel; Lee, Yueh Z.; Lu, Jianping; Chang, Sha; Zhou, Otto

    2014-03-01

    Microbeam radiation therapy (MRT) is a promising experimental and preclinical radiotherapy method for cancer treatment. Synchrotron based MRT experiments have shown that spatially fractionated microbeam radiation has the unique capability of preferentially eradicating tumour cells while sparing normal tissue in brain tumour bearing animal models. We recently demonstrated the feasibility of generating orthovoltage microbeam radiation with an adjustable microbeam width using a carbon nanotube based x-ray source array. Here we report the preliminary results from our efforts in developing an image guidance procedure for the targeted delivery of the narrow microbeams to the small tumour region in the mouse brain. Magnetic resonance imaging was used for tumour identification, and on-board x-ray radiography was used for imaging of landmarks without contrast agents. The two images were aligned using 2D rigid body image registration to determine the relative position of the tumour with respect to a landmark. The targeting accuracy and consistency were evaluated by first irradiating a group of mice inoculated with U87 human glioma brain tumours using the present protocol and then determining the locations of the microbeam radiation tracks using γ-H2AX immunofluorescence staining. The histology results showed that among 14 mice irradiated, 11 received the prescribed number of microbeams on the targeted tumour, with an average localization accuracy of 454 µm measured directly from the histology (537 µm if measured from the registered histological images). Two mice received one of the three prescribed microbeams on the tumour site. One mouse was excluded from the analysis due to tissue staining errors.

  18. Molecular characterization of a dual endothelin-1/Angiotensin II receptor.

    PubMed Central

    Ruiz-Opazo, N.; Hirayama, K.; Akimoto, K.; Herrera, V. L.

    1998-01-01

    BACKGROUND: The molecular recognition theory (MRT) provides a conceptual framework that could explain the evolution of intermolecular and intramolecular interaction of peptides and proteins. As such, it predicts that binding sites of peptide hormones, and its receptor binding sites were originally encoded by and evolved from complementary strands of genomic DNA. MATERIALS AND METHODS: On the basis of principles underlying the MRT, we screened a rat brain complementary DNA library using an AngII followed by an endothelin-1 (ET-1) antisense oligonucleotide probe, expecting to isolate potential cognate receptors. RESULTS: An identical cDNA clone was isolated independently from both the AngII and ET-1 oligonucleotide screenings. Structural analysis revealed a receptor polypeptide containing a single predicted transmembrane region with distinct ET-1 and AngII putative binding domains. Functional analysis demonstrated ET-1- and AngII-specific binding as well as ET-1- and AngII-induced coupling to a Ca2+ mobilizing transduction system. Amino acid substitutions within the predicted ET-1 binding domain obliterate ET-1 binding while preserving AngII binding, thus defining the structural determinants of ET-1 binding within the dual ET-1/AngII receptor, as well as corroborating the dual nature of the receptor. CONCLUSIONS: Elucidation of the dual ET-1/AngII receptor provides further molecular genetic evidence in support of the molecular recognition theory and identifies for the first time a molecular link between the ET-1 and AngII hormonal systems that could underlie observed similar physiological responses elicited by ET-1 and AngII in different organ systems. The prominent expression of the ET-1/AngII receptor mRNA in brain and heart tissues suggests an important role in cardiovascular function in normal and pathophysiological states. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:9508787

  19. Identification of the Quorum-Sensing Target DNA Sequence and N-Acyl Homoserine Lactone Responsiveness of the Brucella abortus virB promoter▿

    PubMed Central

    Arocena, Gastón M.; Sieira, Rodrigo; Comerci, Diego J.; Ugalde, Rodolfo A.

    2010-01-01

    VjbR is a LuxR-type quorum-sensing (QS) regulator that plays an essential role in the virulence of the intracellular facultative pathogen Brucella, the causative agent of brucellosis. It was previously described that VjbR regulates a diverse group of genes, including the virB operon. The latter codes for a type IV secretion system (T4SS) that is central for the pathogenesis of Brucella. Although the regulatory role of VjbR on the virB promoter (PvirB) was extensively studied by different groups, the VjbR-binding site had not been identified so far. Here, we identified the target DNA sequence of VjbR in PvirB by DNase I footprinting analyses. Surprisingly, we observed that VjbR specifically recognizes a sequence that is identical to a half-binding site of the QS-related regulator MrtR of Mesorhizobium tianshanense. As shown by DNase I footprinting and electrophoretic mobility shift assays, generation of a palindromic MrtR-like-binding site in PvirB increased both the affinity and the stability of the VjbR-DNA complex, which confirmed that the QS regulator of Brucella is highly related to that of M. tianshanense. The addition of N-dodecanoyl homoserine lactone dissociated VjbR from the promoter, which confirmed previous reports that indicated a negative effect of this signal on the VjbR-mediated activation of PvirB. Our results provide new molecular evidence for the structure of the virB promoter and reveal unusual features of the QS target DNA sequence of the main regulator of virulence in Brucella. PMID:20400542

  20. Weak extremely-low-frequency magnetic fields and regeneration in the planarian Dugesia tigrina

    SciTech Connect

    Jenrow, K.A.; Smith, C.H.; Liboff, A.R.

    1995-06-01

    Extremely-low-frequency (ELF), low-intensity magnetic fields have been shown to influence cell signaling processes in a variety of systems, both in vivo and in vitro. Similar effects have been demonstrated for nervous system development and neurite outgrowth. The authors report that regeneration in planaria, which incorporates many of these processes, is also affected by ELF magnetic fields. The rate of cephalic regeneration, reflected by the mean regeneration time (MRT), for planaria populations regenerating under continuous exposure to combined DC (78.4 {mu}T) and AC (60.0 Hz at 10.0 {mu}T{sub peak}) magnetic fields applied in parallel was found to be significantly delayed (P {much_lt} 0.001) by 48 {+-} 1 h relative to two different types of control populations (MRT {minus}140 {+-} 12 h). One control population was exposed to only the AC component of this field combination, while the other experienced only the ambient geomagnetic field. All measurements were conducted in a low-gradient, low-noise magnetics laboratory under well-maintained temperature conditions. This delay in regeneration was shown to be dependent on the planaria having a fixed orientation with respect to the magnetic field vectors. Results also indicate that this orientation-dependent transduction process does not result from Faraday induction but is consistent with a Ca{sup 2+} cyclotron resonance mechanism. Data interpretation also permits the tentative conclusion that the effect results from an inhibition of events at an early stage in the regeneration process before the onset of proliferation and differentiation.

  1. Microrobotic navigable entities for Magnetic Resonance Targeting.

    PubMed

    Martel, Sylvain

    2010-01-01

    Magnetic Resonance Targeting (MRT) uses MRI for gathering tracking data to determine the position of microscale entities with the goal of guiding them towards a specific target in the body accessible through the vascular network. At full capabilities, a MRT platform designed to treat a human would consist of a clinical MRI scanner running special algorithms and upgraded to provide propulsion gradient up to approximately 400mT/m to enable entities as small as a few tens of micrometers in diameter and containing magnetic nanoparticles (MNP) to be steered at vessel bifurcations based on tracking information. Indeed, using a clinical MRI system, we showed that such single entity with a diameter as small as 15microm is detectable in gradient-echo scans. Among many potential interventions, targeted cancer therapy is a good initial application for such new microrobotic approach since secondary toxicity for the patient could be reduced while increasing therapeutic efficacy using lower dosages. Although many types of such entities are needed to provide a larger set of tools, here, only three initial types designed with different functionalities and for different types of cancer are briefly described. Initially designed for targeted chemo-embolization of liver tumors, the first type known as Therapeutic Magnetic Micro-Carriers (TMMC) consists in its present form of approximately 50 microm PLGA microparticles containing therapeutics and approximately 180 nm FeCo MNP. For the second type, MNP are not only used for propulsion and tracking, but also actuation based on a local elevation of the temperature. In its simplest form, it consists of approxiamtely 20 nm MNP embedded in a thermo-sensitive hydrogel known as PNIPA, allowing additional functionalities such as computer triggered drug release and targeted hyperthermia. The third type initially considered to target colorectal tumors, consists of 1-2 microm MR-trackable and controllable MC-1 Magnetotactic Bacteria (MTB) with

  2. Hydrogen-limited growth of hyperthermophilic methanogens at deep-sea hydrothermal vents.

    PubMed

    Ver Eecke, Helene C; Butterfield, David A; Huber, Julie A; Lilley, Marvin D; Olson, Eric J; Roe, Kevin K; Evans, Leigh J; Merkel, Alexandr Y; Cantin, Holly V; Holden, James F

    2012-08-21

    Microbial productivity at hydrothermal vents is among the highest found anywhere in the deep ocean, but constraints on microbial growth and metabolism at vents are lacking. We used a combination of cultivation, molecular, and geochemical tools to verify pure culture H(2) threshold measurements for hyperthermophilic methanogenesis in low-temperature hydrothermal fluids from Axial Volcano and Endeavour Segment in the northeastern Pacific Ocean. Two Methanocaldococcus strains from Axial and Methanocaldococcus jannaschii showed similar Monod growth kinetics when grown in a bioreactor at varying H(2) concentrations. Their H(2) half-saturation value was 66 μM, and growth ceased below 17-23 μM H(2), 10-fold lower than previously predicted. By comparison, measured H(2) and CH(4) concentrations in fluids suggest that there was generally sufficient H(2) for Methanocaldococcus growth at Axial but not at Endeavour. Fluids from one vent at Axial (Marker 113) had anomalously high CH(4) concentrations and contained various thermal classes of methanogens based on cultivation and mcrA/mrtA analyses. At Endeavour, methanogens were largely undetectable in fluid samples based on cultivation and molecular screens, although abundances of hyperthermophilic heterotrophs were relatively high. Where present, Methanocaldococcus genes were the predominant mcrA/mrtA sequences recovered and comprised ∼0.2-6% of the total archaeal community. Field and coculture data suggest that H(2) limitation may be partly ameliorated by H(2) syntrophy with hyperthermophilic heterotrophs. These data support our estimated H(2) threshold for hyperthermophilic methanogenesis at vents and highlight the need for coupled laboratory and field measurements to constrain microbial distribution and biogeochemical impacts in the deep sea. PMID:22869718

  3. Excretion patterns of fluid and different sized particle passage markers in banteng (Bos javanicus) and pygmy hippopotamus (Hexaprotodon liberiensis): two functionally different foregut fermenters.

    PubMed

    Schwarm, Angela; Ortmann, Sylvia; Wolf, Christian; Streich, W Jürgen; Clauss, Marcus

    2008-05-01

    Processing of ingesta particles plays a crucial role in the digestive physiology of herbivores. In the ruminant forestomach different sized particles are stratified into a small and a large particle fraction and only the latter is regurgitated and remasticated to smaller, easier-to-digest particles. In contrast, it has been suggested that in non-ruminating foregut fermenters, such as hippopotamuses, larger particles should be selectively excreted since they tend to be digested at a slower rate and hence can be considered intake-limiting bulk. In our study we determined the mean retention time (MRT) of fluids and different sized particles (2 mm and 10 mm) in six pygmy hippos (Hexaprotodon liberiensis) and six banteng (Bos javanicus) on a diet of fresh grass at two intake levels. We used cobalt ethylendiamintetraacetate (Co-EDTA) as fluid and chromium (Cr)-mordanted fibre (2 mm) and cerium (Ce)-mordanted fibre (10 mm) as particle markers, mixed in the food. Average total tract MRT for fluid, small and large particles at the high intake level was 32, 76 and 73 h in pygmy hippos and 25, 56 and 60 h in banteng, and at the low intake level 39, 109, and 105 h in pygmy hippos and 22, 51 and 58 h in banteng, respectively. In accordance with the prediction, large particles moved faster than, or as fast as the small particles, through the gut of pygmy hippos. In contrast, large particles were excreted slower than the small particles in the ruminant of this study, the banteng. Pygmy hippos had longer retention times than the banteng, which probably compensate for the less efficient particle size reduction. Although the results were not as distinct as expected, most likely due to the fact that ingestive mastication of the larger particle marker could not be prevented, they confirm our hypothesis of a functional difference in selective particle retention between ruminating and non-ruminating foregut fermenters.

  4. Influence of a Counterion on the Ion Atmosphere of an Anion: A Molecular Dynamics Study of LiX and CsX (X = F(-), Cl(-), I(-)) in Methanol.

    PubMed

    Kumar, Parveen; Kulkarni, Anant D; Yashonath, S

    2015-08-27

    We report molecular dynamics (MD) simulations to explore the influence of a counterion on the structure and dynamics of cationic and anionic solvation shells for various ions in methanol at 298 K. We show that the variation in ionic size of either the cation or the anion in an ion pair influences the solvation structure of the other ion as well as the diffusivity in an electrolyte solution of methanol. The extent of ionic association between the cation and its counteranion of different ionic sizes has been investigated by analyzing the radial distribution functions (RDFs) and the orientation of methanol molecules in the first solvation shell (FSS) of ions. It is shown that the methanol in the FSS of the anion as well the cation exhibit quite different radial and orientational structures as compared to methanol which lie in the FSS of either the anion or the cation but not both. We find that the coordination number (CN) of F(-), Cl(-), and I(-) ions decreases with increasing size of the anion which is contrary to the trend reported for the anions in H2O. The mean residence time (MRT) of methanol molecules in the FSS of ions has been calculated using the stable states picture (SSP) approach. It is seen that the ion-counterion interaction has a considerable influence on the MRT of methanol molecules in the FSS of ions. We also discuss the stability order of the ion-counterion using the potentials of mean force (PMFs) for ion pairs with ions of different sizes. The PMF plots reveal that the Li(+)-F(-) pair (small-small) is highly stable and the Li(+)-I(-) pair is least stable (small-large) in electrolyte solutions.

  5. [Surgical safety cheklist at the management of the hybrid operating room].

    PubMed

    Cherkashin, M A; Berezina, N A; Kuplevatsky, V I; Serov, A V; Mefodovsky, A A

    2016-01-01

    An essential aspect of the work of the operating room is the provision of safety of both the patient and staff. The organization of the activity of the surgical service requires serious elaboration of each of its stage, as well as standardization in using various validated instruments. When speaking of a hybrid operating room with the use of intraoperative magnetic resonance tomography, such an approach becomes not merely a recommendation but rather forced and justified necessity. Simultaneous use of various technologies of imaging and treatment with the engagement of physicians of various specialties requires especially thorough control. A generally accepted international standard of the work of the operating block is the use of checklists, and since 2008 the initiative of the World Health Organization "Safe Surgery Saves Lives" has globally been working to promote implementation of the WHO Surgical Safety Checklists (SSCL) to the real clinical practice. The intraoperative MR-diagnostic stage dictates rigid requirements for proper inventory of ferromagnetic and nonmagnetic surgical tools, verified logistics, and routing of the patient in the conditions of high and extremely high (1.5-3.0 T) magnetic field. A separate and not less important problem is anaesthesiological support during MRT. In order to optimise the patient's movements and adequate monitoring of his/her safety inside the operating department, the authors have modified the standard WHO Surgical Safety Checklist. Implementation of the modified checklist for the MRT-equipped hybrid operating room should improve the control over the processes, as well as increase safety of both the patient and personnel.

  6. Genetics of Bladder Malignant Tumors in Childhood

    PubMed Central

    Zangari, Andrea; Zaini, Johan; Gulìa, Caterina

    2016-01-01

    Bladder masses are represented by either benign or malignant entities. Malignant bladder tumors are frequent causes of disease and death in western countries. However, in children they are less common. Additionally, different features are found in childhood, in which non epithelial tumors are more common than epithelial ones. Rhabdomyosarcoma is the most common pediatric bladder tumor, but many other types of lesions may be found, such as malignant rhabdoid tumor (MRT), inflammatory myofibroblastic tumor and neuroblastoma. Other rarer tumors described in literature include urothelial carcinoma and other epithelial neoplasms. Rhabdomyosarcoma is associated to a variety of genetic syndromes and many genes are involved in tumor development. PAX3-FKHR and PAX7-FKHR (P-F) fusion state has important implications in the pathogenesis and biology of RMS, and different genes alterations are involved in the pathogenesis of P-F negative and embryonal RMS, which are the subsets of tumors most frequently affecting the bladder. These genes include p53, MEF2, MYOG, Ptch1, Gli1, Gli3, Myf5, MyoD1, NF1, NRAS, KRAS, HRAS, FGFR4, PIK3CA, CTNNB1, FBXW7, IGF1R, PDGFRA, ERBB2/4, MET, BCOR. Malignant rhabdoid tumor (MRT) usually shows SMARCB1/INI1 alterations. Anaplastic lymphoma kinase (ALK) gene translocations are the most frequently associated alterations in inflammatory myofibroblastic tumor (IMT). Few genes alterations in urothelial neoplasms have been reported in the paediatric population, which are mainly related to deletion of p16/lnk4, overexpression of CK20 and overexpression of p53. Here, we reviewed available literature to identify genes associated to bladder malignancies in children and discussed their possible relationships with these tumors. PMID:27013922

  7. Interactive control of minerals, wildfire, and erosion on soil carbon stabilization in conifer ecosystems of the western U.S.

    NASA Astrophysics Data System (ADS)

    Rasmussen, C.

    2014-12-01

    Answering the question of what controls the fate and stabilization of organic carbon in forest soils is central to understanding the role of western US ecosystems in mitigating climate change, optimizing forest management, and quantifying local and regional terrestrial carbon budgets. Over half of forest soil C is stored belowground, stabilized by a number of separate, but interacting physical, chemical and biological mechanisms. Here we synthesize data from a series of field and laboratory studies focused on identifying mineral, physical, and landscape position controls on belowground C stabilization mechanisms in western U.S. conifer ecosystems. Results from these studies demonstrate an important for role for short-range-order Fe- and Al-oxyhydroxides and Al-humus complexes in C stabilization, and that the soil mineral assemblage moderates C cycling via control on partitioning of C into physical fractions ("free", "occluded", "mineral") with varying MRT and chemistry. Measures of occluded fraction chemical composition by 13C-NMR indicate this fraction is 2-5 times more enriched in pyrogenic C than the bulk soil and that this fraction is on the order of ~25 to 65% charred materials. Radiocarbon analyses of a large set of conifer soil samples from California and Arizona further indicate the occluded fraction is generally older than either the free light or mineral fraction. In particular, soil C in convergent, water and sediment gathering portions of the landscape are enriched in long MRT charred materials. These results indicate an important role for the interaction of soil mineral assemblage, wildfire, and erosion in controlling belowground C storage and stabilization in western conifer forests. Drought and wildfire are expected to increase with climate change and thus may exert significant control on belowground C storage directly through biochemical and physical changes in aboveground biomass, production of charred materials, and indirectly via post

  8. Optically erasable samarium-doped fluorophosphate glasses for high-dose measurements in microbeam radiation therapy

    NASA Astrophysics Data System (ADS)

    Morrell, B.; Okada, G.; Vahedi, S.; Koughia, C.; Edgar, A.; Varoy, C.; Belev, G.; Wysokinski, T.; Chapman, D.; Sammynaiken, R.; Kasap, S. O.

    2014-02-01

    Previous work has demonstrated that fluorophosphate (FP) glasses doped with trivalent samarium (Sm3+) can be used as a dosimetric detector in microbeam radiation therapy (MRT) to measure high radiation doses and large dose variations with a resolution in the micrometer range. The present work addresses the use of intense optical radiation at 405 nm to erase the recorded dose information in Sm3+-doped FP glass plates and examines the underlying physics. We have evaluated both the conversion and optical erasure of Sm3+-doped FP glasses using synchrotron-generated high-dose x-rays at the Canadian Light Source. The Sm-ion valency conversion is accompanied by the appearance of x-ray induced optical absorbance due to the trapping of holes and electrons into phosphorus-oxygen hole (POHC) and electron (POEC) capture centers. Nearly complete Sm2+ to Sm3+ reconversion (erasure) may be achieved by intense optical illumination. Combined analysis of absorbance and electron spin resonance measurements indicates that the optical illumination causes partial disappearance of the POHC and the appearance of new POEC. The suggested model for the observed phenomena is based on the release of electrons during the Sm2+ to Sm3+ reconversion process, the capture of these electrons by POHC (and hence their disappearance), or by PO groups, with the appearance of new and/or additional POEC. Optical erasure may be used as a practical means to erase the recorded data and permits the reuse of these Sm-doped FP glasses in monitoring dose in MRT.

  9. Pharmacokinetic comparisons by UPLC-MS/MS of isomer paeoniflorin and albiflorin after oral administration decoctions of single-herb Radix Paeoniae Alba and Zengmian Yiliu prescription to rats.

    PubMed

    Gong, Can; Yang, Hong; Wei, Hai; Qi, Cong; Wang, Chang-Hong

    2015-03-01

    Zengmian Yiliu (ZMYL), a traditional Chinese formula, is designed to improve clinical efficacy and reduce adverse effects in combination with cisplatin in ovarian cancer chemotherapy. In ZMYL, Radix Paeoniae Alba (RPA, made from root of Paeonia lactiflora Pall.) acts as an adjunctive drug in cancer treatment by ameliorating side effects induced by radio- and chemotherapy. The pharmacokinetics differences between isomer albiflorin and paeoniflorin, the main components of RPA, after oral administration decoction of single-herb RPA and ZMYL were compared using a sensitive and accurate UPLC-MS/MS. The results indicate that there are statistically significant differences between the pharmacokinetic parameters: decreasing area under the plasma concentration-time curve (AUC), maximum concentration (Cmax ), elimination rate constant (Ke ) and increasing apparent volume of distribution (Vd ) and clearance (CL) for albiflorin, increasing distribution half-life (T1/2d ) and decreasing elimination half-life (T1/2e ), distribution rate constant (Kd ) and absorption rate constant (Ka ) for paeoniflorin in the ZMYL group compared with the single-herb RPA group. In comparison with albiflorin, the pharmacokinetic parameters of paeoniflorin included significantly increasing mean residence time (MRT) and Vd , decreasing CL and Ke in the single-herb RPA group and increasing MRT and T1/2d and decreasing CL, Ke and Kd in the ZMYL group. Both paeoniflorin and albiflorin are more likely, as the main active ingredients in RPA and ZMYL, to play a variety of pharmacological effects, and herb-herb interactions occur, resulting in different pharmacokinetics of albiflorin and paeoniflorin in RPA and ZMYL.

  10. Excretion patterns of fluid and different sized particle passage markers in banteng (Bos javanicus) and pygmy hippopotamus (Hexaprotodon liberiensis): two functionally different foregut fermenters.

    PubMed

    Schwarm, Angela; Ortmann, Sylvia; Wolf, Christian; Streich, W Jürgen; Clauss, Marcus

    2008-05-01

    Processing of ingesta particles plays a crucial role in the digestive physiology of herbivores. In the ruminant forestomach different sized particles are stratified into a small and a large particle fraction and only the latter is regurgitated and remasticated to smaller, easier-to-digest particles. In contrast, it has been suggested that in non-ruminating foregut fermenters, such as hippopotamuses, larger particles should be selectively excreted since they tend to be digested at a slower rate and hence can be considered intake-limiting bulk. In our study we determined the mean retention time (MRT) of fluids and different sized particles (2 mm and 10 mm) in six pygmy hippos (Hexaprotodon liberiensis) and six banteng (Bos javanicus) on a diet of fresh grass at two intake levels. We used cobalt ethylendiamintetraacetate (Co-EDTA) as fluid and chromium (Cr)-mordanted fibre (2 mm) and cerium (Ce)-mordanted fibre (10 mm) as particle markers, mixed in the food. Average total tract MRT for fluid, small and large particles at the high intake level was 32, 76 and 73 h in pygmy hippos and 25, 56 and 60 h in banteng, and at the low intake level 39, 109, and 105 h in pygmy hippos and 22, 51 and 58 h in banteng, respectively. In accordance with the prediction, large particles moved faster than, or as fast as the small particles, through the gut of pygmy hippos. In contrast, large particles were excreted slower than the small particles in the ruminant of this study, the banteng. Pygmy hippos had longer retention times than the banteng, which probably compensate for the less efficient particle size reduction. Although the results were not as distinct as expected, most likely due to the fact that ingestive mastication of the larger particle marker could not be prevented, they confirm our hypothesis of a functional difference in selective particle retention between ruminating and non-ruminating foregut fermenters. PMID:18378479

  11. Indocyanine green clearance varies as a function of N-acetylcysteine treatment in a murine model of acetaminophen toxicity.

    PubMed

    Milesi-Hallé, Alessandra; Abdel-Rahman, Susan M; Brown, Aliza; McCullough, Sandra S; Letzig, Lynda; Hinson, Jack A; James, Laura P

    2011-02-01

    Standard assays to assess acetaminophen (APAP) toxicity in animal models include determination of ALT (alanine aminotransferase) levels and examination of histopathology of liver sections. However, these assays do not reflect the functional capacity of the injured liver. To examine a functional marker of liver injury, the pharmacokinetics of indocyanine green (ICG) were examined in mice treated with APAP, saline, or APAP followed by N-acetylcysteine (NAC) treatment.Male B6C3F1 mice were administered APAP (200 mg/kg IP) or saline. Two additional groups of mice received APAP followed by NAC at 1 or 4 h after APAP. At 24 h, mice were injected with ICG (10 mg/kg IV) and serial blood samples (0, 2, 10, 30, 50 and 75 min) were obtained for determination of serum ICG concentrations and ALT. Mouse livers were removed for measurement of APAP protein adducts and examination of histopathology. Toxicity (ALT values and histology) was significantly increased above saline treated mice in the APAP and APAP/NAC 4 h mice. Mice treated with APAP/NAC 1 h had complete protection from toxicity. APAP protein adducts were increased in all APAP treated groups and were highest in the APAP/NAC 1 h group. Pharmacokinetic analysis of ICG demonstrated that the total body clearance (Cl(T)) of ICG was significantly decreased and the mean residence time (MRT) was significantly increased in the APAP mice compared to the saline mice. Mice treated with NAC at 1 h had Cl(T) and MRT values similar to those of saline treated mice. Conversely, mice that received NAC at 4 h had a similar ICG pharmacokinetic profile to that of the APAP only mice. Prompt treatment with NAC prevented loss of functional activity while late treatment with NAC offered no improvement in ICG clearance at 24 h. ICG clearance in mice with APAP toxicity can be utilized in future studies testing the effects of novel treatments for APAP toxicity.

  12. Image-guided microbeam irradiation to brain tumour bearing mice using a carbon nanotube x-ray source array.

    PubMed

    Zhang, Lei; Yuan, Hong; Burk, Laurel M; Inscoe, Christy R; Hadsell, Michael J; Chtcheprov, Pavel; Lee, Yueh Z; Lu, Jianping; Chang, Sha; Zhou, Otto

    2014-03-01

    Microbeam radiation therapy (MRT) is a promising experimental and preclinical radiotherapy method for cancer treatment. Synchrotron based MRT experiments have shown that spatially fractionated microbeam radiation has the unique capability of preferentially eradicating tumour cells while sparing normal tissue in brain tumour bearing animal models. We recently demonstrated the feasibility of generating orthovoltage microbeam radiation with an adjustable microbeam width using a carbon nanotube based x-ray source array. Here we report the preliminary results from our efforts in developing an image guidance procedure for the targeted delivery of the narrow microbeams to the small tumour region in the mouse brain. Magnetic resonance imaging was used for tumour identification, and on-board x-ray radiography was used for imaging of landmarks without contrast agents. The two images were aligned using 2D rigid body image registration to determine the relative position of the tumour with respect to a landmark. The targeting accuracy and consistency were evaluated by first irradiating a group of mice inoculated with U87 human glioma brain tumours using the present protocol and then determining the locations of the microbeam radiation tracks using γ-H2AX immunofluorescence staining. The histology results showed that among 14 mice irradiated, 11 received the prescribed number of microbeams on the targeted tumour, with an average localization accuracy of 454 µm measured directly from the histology (537 µm if measured from the registered histological images). Two mice received one of the three prescribed microbeams on the tumour site. One mouse was excluded from the analysis due to tissue staining errors.

  13. Dynamic T{sub 2}-mapping during magnetic resonance guided high intensity focused ultrasound ablation of bone marrow

    SciTech Connect

    Waspe, Adam C.; Looi, Thomas; Mougenot, Charles; Amaral, Joao; Temple, Michael; Sivaloganathan, Siv; Drake, James M.

    2012-11-28

    Focal bone tumor treatments include amputation, limb-sparing surgical excision with bone reconstruction, and high-dose external-beam radiation therapy. Magnetic resonance guided high intensity focused ultrasound (MR-HIFU) is an effective non-invasive thermotherapy for palliative management of bone metastases pain. MR thermometry (MRT) measures the proton resonance frequency shift (PRFS) of water molecules and produces accurate (<1 Degree-Sign C) and dynamic (<5s) thermal maps in soft tissues. PRFS-MRT is ineffective in fatty tissues such as yellow bone marrow and, since accurate temperature measurements are required in the bone to ensure adequate thermal dose, MR-HIFU is not indicated for primary bone tumor treatments. Magnetic relaxation times are sensitive to lipid temperature and we hypothesize that bone marrow temperature can be determined accurately by measuring changes in T{sub 2}, since T{sub 2} increases linearly in fat during heating. T{sub 2}-mapping using dual echo times during a dynamic turbo spin-echo pulse sequence enabled rapid measurement of T{sub 2}. Calibration of T{sub 2}-based thermal maps involved heating the marrow in a bovine femur and simultaneously measuring T{sub 2} and temperature with a thermocouple. A positive T{sub 2} temperature dependence in bone marrow of 20 ms/ Degree-Sign C was observed. Dynamic T{sub 2}-mapping should enable accurate temperature monitoring during MR-HIFU treatment of bone marrow and shows promise for improving the safety and reducing the invasiveness of pediatric bone tumor treatments.

  14. Long Term Effect of Land Reclamation from Lake on Chemical Composition of Soil Organic Matter and Its Mineralization

    PubMed Central

    He, Dongmei; Ruan, Honghua

    2014-01-01

    Since the late 1950s, land reclamation from lakes has been a common human disturbance to ecosystems in China. It has greatly diminished the lake area, and altered natural ecological succession. However, little is known about its impact on the carbon (C) cycle. We conducted an experiment to examine the variations of chemical properties of dissolved organic matter (DOM) and C mineralization under four land uses, i.e. coniferous forest (CF), evergreen broadleaf forest (EBF), bamboo forest (BF) and cropland (CL) in a reclaimed land area from Taihu Lake. Soils and lake sediments (LS) were incubated for 360 days in the laboratory and the CO2 evolution from each soil during the incubation was fit to a double exponential model. The DOM was analyzed at the beginning and end of the incubation using UV and fluorescence spectroscopy to understand the relationships between DOM chemistry and C mineralization. The C mineralization in our study was influenced by the land use with different vegetation and management. The greatest cumulative CO2-C emission was observed in BF soil at 0–10 cm depth. The active C pool in EBF at 10–25 cm had longer (62 days) mean residence time (MRT). LS showed the highest cumulative CO2-C and shortest MRT comparing with the terrestrial soils. The carbohydrates in DOM were positively correlated with CO2-C evolution and negatively correlated to phenols in the forest soils. Cropland was consistently an outlier in relationships between DOM chemistry and CO2-evolution, highlighting the unique effects that this land use on soil C cycling, which may be attributed the tillage practices. Our results suggest that C mineralization is closely related to the chemical composition of DOM and sensitive to its variation. Conversion of an aquatic ecosystem into a terrestrial ecosystem may alter the chemical structure of DOM, and then influences soil C mineralization. PMID:24905998

  15. [Surgical safety cheklist at the management of the hybrid operating room].

    PubMed

    Cherkashin, M A; Berezina, N A; Kuplevatsky, V I; Serov, A V; Mefodovsky, A A

    2016-01-01

    An essential aspect of the work of the operating room is the provision of safety of both the patient and staff. The organization of the activity of the surgical service requires serious elaboration of each of its stage, as well as standardization in using various validated instruments. When speaking of a hybrid operating room with the use of intraoperative magnetic resonance tomography, such an approach becomes not merely a recommendation but rather forced and justified necessity. Simultaneous use of various technologies of imaging and treatment with the engagement of physicians of various specialties requires especially thorough control. A generally accepted international standard of the work of the operating block is the use of checklists, and since 2008 the initiative of the World Health Organization "Safe Surgery Saves Lives" has globally been working to promote implementation of the WHO Surgical Safety Checklists (SSCL) to the real clinical practice. The intraoperative MR-diagnostic stage dictates rigid requirements for proper inventory of ferromagnetic and nonmagnetic surgical tools, verified logistics, and routing of the patient in the conditions of high and extremely high (1.5-3.0 T) magnetic field. A separate and not less important problem is anaesthesiological support during MRT. In order to optimise the patient's movements and adequate monitoring of his/her safety inside the operating department, the authors have modified the standard WHO Surgical Safety Checklist. Implementation of the modified checklist for the MRT-equipped hybrid operating room should improve the control over the processes, as well as increase safety of both the patient and personnel. PMID:27336334

  16. Male-typical visuospatial functioning in gynephilic girls with gender dysphoria — organizational and activational effects of testosterone

    PubMed Central

    Burke, Sarah M.; Kreukels, Baudewijntje P.C.; Cohen-Kettenis, Peggy T.; Veltman, Dick J.; Klink, Daniel T.; Bakker, Julie

    2016-01-01

    Background Sex differences in performance and regional brain activity during mental rotation have been reported repeatedly and reflect organizational and activational effects of sex hormones. We investigated whether adolescent girls with gender dysphoria (GD), before and after 10 months of testosterone treatment, showed male-typical brain activity during a mental rotation task (MRT). Methods Girls with GD underwent fMRI while performing the MRT twice: when receiving medication to suppress their endogenous sex hormones before onset of testosterone treatment, and 10 months later during testosterone treatment. Two age-matched control groups participated twice as well. Results We included 21 girls with GD, 20 male controls and 21 female controls in our study. In the absence of any group differences in performance, control girls showed significantly increased activation in frontal brain areas compared with control boys (pFWE = 0.012). Girls with GD before testosterone treatment differed significantly in frontal brain activation from the control girls (pFWE = 0.034), suggesting a masculinization of brain structures associated with visuospatial cognitive functions. After 10 months of testosterone treatment, girls with GD, similar to the control boys, showed increases in brain activation in areas implicated in mental rotation. Limitations Since all girls with GD identified as gynephilic, their resemblance in spatial cognition with the control boys, who were also gynephilic, may have been related to their shared sexual orientation rather than their shared gender identity. We did not account for menstrual cycle phase or contraceptive use in our analyses. Conclusion Our findings suggest atypical sexual differentiation of the brain in natal girls with GD and provide new evidence for organizational and activational effects of testosterone on visuospatial cognitive functioning. PMID:27070350

  17. Rectal Cancer: Mucinous Carcinoma on Magnetic Resonance Imaging Indicates Poor Response to Neoadjuvant Chemoradiation

    SciTech Connect

    Oberholzer, Katja; Menig, Matthias; Kreft, Andreas; Schneider, Astrid; Junginger, Theodor; Heintz, Achim; Kreitner, Karl-Friedrich; Hoetker, Andreas M.; Hansen, Torsten; Dueber, Christoph; Schmidberger, Heinz

    2012-02-01

    Purpose: To assess response of locally advanced rectal carcinoma to chemoradiation with regard to mucinous status and local tumor invasion found at pretherapeutic magnetic resonance imaging (MRI). Methods and Materials: A total of 88 patients were included in this prospective study of patients with advanced mrT3 and mrT4 carcinomas. Carcinomas were categorized by MRI as mucinous (mucin proportion >50% within the tumor volume), and as nonmucinous. Patients received neoadjuvant chemoradiation consisting of 50.4 Gy (1.8 Gy/fraction) and 5-fluorouracil on Days 1 to 5 and Days 29 to 33. Therapy response was assessed by comparing pretherapeutic MRI with histopathology of surgical specimens (minimum distance between outer tumor edge and circumferential resection margin = CRM, T, and N category). Results: A mucinous carcinoma was found in 21 of 88 patients. Pretherapeutic mrCRM was 0 mm (median) in the mucinous and nonmucinous group. Of the 88 patients, 83 underwent surgery with tumor resection. The ypCRM (mm) at histopathology was significantly lower in mucinous carcinomas than in nonmucinous carcinomas (p {<=} 0.001). Positive resection margins (ypCRM {<=} 1 mm) were found more frequently in mucinous carcinomas than in nonmucinous ones (p {<=} 0.001). Treatment had less effect on local tumor stage in mucinous carcinomas than in nonmucinous carcinomas (for T downsizing, p = 0.012; for N downstaging, p = 0.007). Disease progression was observed only in patients with mucinous carcinomas (n = 5). Conclusion: Mucinous status at pretherapeutic MRI was associated with a noticeably worse response to chemoradiation and should be assessed by MRI in addition to local tumor staging to estimate response to treatment before it is initiated.

  18. An investigation of the potential of optical computed tomography for imaging of synchrotron-generated x-rays at high spatial resolution

    NASA Astrophysics Data System (ADS)

    Doran, Simon J.; Brochard, Thierry; Adamovics, John; Krstajic, Nikola; Bräuer-Krisch, Elke

    2010-03-01

    X-ray microbeam radiation therapy (MRT) is a novel form of treatment, currently in its preclinical stage, which uses microplanar x-ray beams from a synchrotron radiation source. It is important to perform accurate dosimetry on these microbeams, but, to date, there has been no accurate enough method available for making 3D dose measurements with isotropic, high spatial resolution to verify the results of Monte Carlo dose simulations. Here, we investigate the potential of optical computed tomography for satisfying these requirements. The construction of a simple optical CT microscopy (optical projection tomography) system from standard commercially available hardware is described. The measurement of optical densities in projection data is shown to be highly linear (r2 = 0.999). The depth-of-field (DOF) of the imaging system is calculated based on the previous literature and measured experimentally using a commercial DOF target. It is shown that high quality images can be acquired despite the evident lack of telecentricity and despite DOF of the system being much lower than the sample diameter. Possible reasons for this are discussed. Results are presented for a complex irradiation of a 22 mm diameter cylinder of the radiochromic polymer PRESAGE™, demonstrating the exquisite 'dose-painting' abilities available in the MRT hutch of beamline ID-17 at the European Synchrotron Radiation Facility. Dose distributions in this initial experiment are equally well resolved on both an optical CT scan and a corresponding transmission image of radiochromic film, down to a line width of 83 µm (6 lp mm-1) with an MTF value of 0.40. A group of 33 µm wide lines was poorly resolved on both the optical CT and film images, and this is attributed to an incorrect exposure time calculation, leading to under-delivery of dose. Image artefacts in the optical CT scan are discussed. PRESAGE™ irradiated using the microbeam facility is proposed as a suitable material for producing phantom

  19. Improved normal tissue protection by proton and X-ray microchannels compared to homogeneous field irradiation.

    PubMed

    Girst, S; Marx, C; Bräuer-Krisch, E; Bravin, A; Bartzsch, S; Oelfke, U; Greubel, C; Reindl, J; Siebenwirth, C; Zlobinskaya, O; Multhoff, G; Dollinger, G; Schmid, T E; Wilkens, J J

    2015-09-01

    The risk of developing normal tissue injuries often limits the radiation dose that can be applied to the tumour in radiation therapy. Microbeam Radiation Therapy (MRT), a spatially fractionated photon radiotherapy is currently tested at the European Synchrotron Radiation Facility (ESRF) to improve normal tissue protection. MRT utilizes an array of microscopically thin and nearly parallel X-ray beams that are generated by a synchrotron. At the ion microprobe SNAKE in Munich focused proton microbeams ("proton microchannels") are studied to improve normal tissue protection. Here, we comparatively investigate microbeam/microchannel irradiations with sub-millimetre X-ray versus proton beams to minimize the risk of normal tissue damage in a human skin model, in vitro. Skin tissues were irradiated with a mean dose of 2 Gy over the irradiated area either with parallel synchrotron-generated X-ray beams at the ESRF or with 20 MeV protons at SNAKE using four different irradiation modes: homogeneous field, parallel lines and microchannel applications using two different channel sizes. Normal tissue viability as determined in an MTT test was significantly higher after proton or X-ray microchannel irradiation compared to a homogeneous field irradiation. In line with these findings genetic damage, as determined by the measurement of micronuclei in keratinocytes, was significantly reduced after proton or X-ray microchannel compared to a homogeneous field irradiation. Our data show that skin irradiation using either X-ray or proton microchannels maintain a higher cell viability and DNA integrity compared to a homogeneous irradiation, and thus might improve normal tissue protection after radiation therapy.

  20. Development and validation of a rotor-gene real-time PCR assay for detection, identification, and quantification of Chlamydia trachomatis in a single reaction.

    PubMed

    Jalal, Hamid; Stephen, Hannah; Curran, Martin D; Burton, Janet; Bradley, Michelle; Carne, Christopher

    2006-01-01

    A multitarget real-time PCR (MRT-PCR) for detection of Chlamydia trachomatis DNA was developed and validated. There were three targets for amplification in a single reaction: the cryptic plasmid (CP), the major outer membrane protein (MOMP) gene, and an internal control. The assay had the following characteristics: (i) detection and confirmation of the presence of C. trachomatis DNA in a single reaction, (ii) detection of all genovars of C. trachomatis without any cross-reactivity with pathogenic bacteria or commensal organisms of the oropharynx and genital tract, (iii) a 95% probability of detection with three copies of MOMP and one copy of CP per reaction mixture, (iv) identification of the inhibition of amplification, (v) a quantitative dynamic range of 25 to 250,000 genome copies per reaction mixture, (vi) high intra- and interassay reproducibilities, and (vii) correct identification of all samples in the validation panel. There were 146 COBAS Amplicor PCR (Amplicor PCR)-positive samples and 122 Amplicor PCR-negative samples in the panel. MRT-PCR detected CP DNA alone in 6 (4%) Amplicor PCR-positive samples and both CP and MOMP DNAs in 140 (96%) of 146 Amplicor PCR-positive samples. The quantity of MOMP DNA in 95 (68%) of 140 samples was within the dynamic range of the assay. The median C. trachomatis load in these samples was 321 genome copies per reaction mixture (range, 26 to 40,137 genome copies per reaction mixture). Due to the inclusion of two different C. trachomatis-specific targets, the assay confirmed 259 (97%) of 268 results in a single reaction. This assay could be used in the qualitative format for the routine detection of C. trachomatis and in the quantitative format for study of the pathogenesis of C. trachomatis-associated diseases. The assay demonstrated the potential to eliminate the need for confirmatory testing in almost all samples, thus reducing the turnaround time and the workload.

  1. Microanalysis, Pharmacokinetics and Tissue Distribution of Polysaccharide-Protein Complexes from Longan Pulp in Mice

    PubMed Central

    Min, Ting; Sun, Jie; Yi, Yang; Wang, Hong-Xun; Hang, Fei; Ai, You-Wei; Wang, Li-Mei

    2015-01-01

    A high performance size exclusion-fluorescence detection (HPSEC-FD) method combined with fluorescein isothiocyanate (FITC) prelabeling was established for the microanalysis of polysaccharide–protein complexes from longan pulp (LPP). FITC-labeled LPP (LPPF) was fractionated by gel filtration chromatography. The weight-average molecular weight and FITC substitution degree of LPPF were 39.01 kDa and 0.20%, respectively. The HPSEC-FD calibration curves linear over the range of 1–200 µg/mL in mouse plasma, spleen and lung samples with correlation coefficients greater than 0.995. The inter-day and intra-day precisions of the method were not more than 6.9%, and the relative recovery ranged from 93.7% to 106.4%. The concentration–time curve of LPPF in plasma following intravenous (i.v.) administration at 40 mg/kg body weight well fitted to a two-compartment model. LPPF rapidly eliminated from plasma according to the short half-lives (t1/2α = 2.23 min, t1/2β = 39.11 min) and mean retention times (MRT0–t = 1.15 h, MRT0–∞ = 1.39 h). After administration over 5 to 360 min, the concentration of LPPF in spleen homogenate decreased from 7.41 to 3.68 µg/mL; the concentration in lung homogenate decreased from 9.08 to 3.40 µg/mL. On the other hand, the increasing concentration of LPPF fraction with low molecular weight in heart homogenate was observed. PMID:26501257

  2. Pharmacokinetics of puerarin and ginsenoside Rg1 of CBN injection and the relation with platelet aggregation in rats.

    PubMed

    Liu, Ruining; Xing, Dongming; Lu, Hong; Wu, Hao; Du, Lijun

    2006-01-01

    In order to study the pharmacokinetics of puerarin and ginsenoside Rg1 of cerebral blood nutrition (CBN) and its relationship with pharmacodynamics of platelet aggregation induced by ADP in rat, the blood samples after injection were collected. The concentrations of puerarin and ginsenoside Rg1 in plasma were determined by RP-HPLC, and the platelet aggregations were observed simultaneously. The data showed that there was distinct statistic significance (p < 0.01) for puerarin processing, which was a single compartment model with quick elimination rate (t(1/2beta) = 18 min) and MRT (26 min), while ginsenoside Rg1 processing was a double compartment model with rapid distribution rate (t(1/2alpha) = 8 min), slow elimination rate (t(1/2beta) = 11 hours) and MRT (3.3 hours). Effects of anti-platelet aggregation were presented at 5-10 min, 45-90 min and 6-8 hours after injection separately, and the corresponding concentrations of puerarin were 25-21 microg/ml, 4.5-0.8 microg/ml and 0 microg/ml, ginsenoside Rg1 were 7.6-6.7 microg/ml, 1.2-0.6 microg/ml and 1.8-0.5 microg/ml. The two components presented a positive correlation between their concentrations and the effect of anti-platelet aggregation in 5-10 min after CBN injection (coefficient of correlation were 0.999 and 0.995). However, it was noted that the effect was still stronger even when concentrations of puerarin and ginsenoside Rg1 in plasma decreased. Therefore, puerarin and ginsenoside Rg1 not only had different pharmacokinetics, but also had a positive correlation with platelet aggregation, just in 5-10 min after CBN injection.

  3. Modulating mitochondrial quality in disease transmission: towards enabling mitochondrial DNA disease carriers to have healthy children

    PubMed Central

    Diot, Alan; Dombi, Eszter; Lodge, Tiffany; Liao, Chunyan; Morten, Karl; Carver, Janet; Wells, Dagan; Child, Tim; Johnston, Iain G.; Williams, Suzannah; Poulton, Joanna

    2016-01-01

    One in 400 people has a maternally inherited mutation in mtDNA potentially causing incurable disease. In so-called heteroplasmic disease, mutant and normal mtDNA co-exist in the cells of carrier women. Disease severity depends on the proportion of inherited abnormal mtDNA molecules. Families who have had a child die of severe, maternally inherited mtDNA disease need reliable information on the risk of recurrence in future pregnancies. However, prenatal diagnosis and even estimates of risk are fraught with uncertainty because of the complex and stochastic dynamics of heteroplasmy. These complications include an mtDNA bottleneck, whereby hard-to-predict fluctuations in the proportions of mutant and normal mtDNA may arise between generations. In ‘mitochondrial replacement therapy’ (MRT), damaged mitochondria are replaced with healthy ones in early human development, using nuclear transfer. We are developing non-invasive alternatives, notably activating autophagy, a cellular quality control mechanism, in which damaged cellular components are engulfed by autophagosomes. This approach could be used in combination with MRT or with the regular management, pre-implantation genetic diagnosis (PGD). Mathematical theory, supported by recent experiments, suggests that this strategy may be fruitful in controlling heteroplasmy. Using mice that are transgenic for fluorescent LC3 (the hallmark of autophagy) we quantified autophagosomes in cleavage stage embryos. We confirmed that the autophagosome count peaks in four-cell embryos and this correlates with a drop in the mtDNA content of the whole embryo. This suggests removal by mitophagy (mitochondria-specific autophagy). We suggest that modulating heteroplasmy by activating mitophagy may be a useful complement to mitochondrial replacement therapy. PMID:27528757

  4. Modelling thermal comfort of visitors at urban squares in hot and arid climate using NN-ARX soft computing method

    NASA Astrophysics Data System (ADS)

    Kariminia, Shahab; Motamedi, Shervin; Shamshirband, Shahaboddin; Piri, Jamshid; Mohammadi, Kasra; Hashim, Roslan; Roy, Chandrabhushan; Petković, Dalibor; Bonakdari, Hossein

    2016-05-01

    Visitors utilize the urban space based on their thermal perception and thermal environment. The thermal adaptation engages the user's behavioural, physiological and psychological aspects. These aspects play critical roles in user's ability to assess the thermal environments. Previous studies have rarely addressed the effects of identified factors such as gender, age and locality on outdoor thermal comfort, particularly in hot, dry climate. This study investigated the thermal comfort of visitors at two city squares in Iran based on their demographics as well as the role of thermal environment. Assessing the thermal comfort required taking physical measurement and questionnaire survey. In this study, a non-linear model known as the neural network autoregressive with exogenous input (NN-ARX) was employed. Five indices of physiological equivalent temperature (PET), predicted mean vote (PMV), standard effective temperature (SET), thermal sensation votes (TSVs) and mean radiant temperature ( T mrt) were trained and tested using the NN-ARX. Then, the results were compared to the artificial neural network (ANN) and the adaptive neuro-fuzzy inference system (ANFIS). The findings showed the superiority of the NN-ARX over the ANN and the ANFIS. For the NN-ARX model, the statistical indicators of the root mean square error (RMSE) and the mean absolute error (MAE) were 0.53 and 0.36 for the PET, 1.28 and 0.71 for the PMV, 2.59 and 1.99 for the SET, 0.29 and 0.08 for the TSV and finally 0.19 and 0.04 for the T mrt.

  5. [Soil organic carbon pools and their turnover under two different types of forest in Xiao-xing'an Mountains, Northeast China].

    PubMed

    Gao, Fei; Jiang, Hang; Cui, Xiao-yang

    2015-07-01

    Soil samples collected from virgin Korean pine forest and broad-leaved secondary forest in Xiaoxing'an Mountains, Northeast China were incubated in laboratory at different temperatures (8, 18 and 28 °C) for 160 days, and the data from the incubation experiment were fitted to a three-compartment, first-order kinetic model which separated soil organic carbon (SOC) into active, slow, and resistant carbon pools. Results showed that the soil organic carbon mineralization rates and the cumulative amount of C mineralized (all based on per unit of dry soil mass) of the broad-leaved secondary forest were both higher than that of the virgin Korean pine forest, whereas the mineralized C accounted for a relatively smaller part of SOC in the broad-leaved secondary forest soil. Soil active and slow carbon pools decreased with soil depth, while their proportions in SOC increased. Soil resistant carbon pool and its contribution to SOC were both greater in the broad-leaved secondary forest soil than in the virgin Korean pine forest soil, suggesting that the broad-leaved secondary forest soil organic carbon was relatively more stable. The mean retention time (MRT) of soil active carbon pool ranged from 9 to 24 d, decreasing with soil depth; while the MRT of slow carbon pool varied between 7 and 24 a, increasing with soil depth. Soil active carbon pool and its proportion in SOC increased linearly with incubation temperature, and consequently, decreased the slow carbon pool. Virgin Korean pine forest soils exhibited a higher increasing rate of active carbon pool along temperature gradient than the broad-leaved secondary forest soils, indicating that the organic carbon pool of virgin Korean pine forest soil was relatively more sensitive to temperature change.

  6. Modelling digestive constraints in non-ruminant and ruminant foregut-fermenting mammals.

    PubMed

    Munn, Adam J; Streich, W Jürgen; Hummel, Jürgen; Clauss, Marcus

    2008-09-01

    It has been suggested that large foregut-fermenting marsupial herbivores, the kangaroos and their relatives, may be less constrained by food intake limitations as compared with ruminants, due mainly to differences in their digestive morphology and management of ingesta particles through the gut. In particular, as the quality of forage declines with increasing contents of plant fibre (cellulose, hemicelluloses and lignin; measured as neutral-detergent fibre, NDF), the tubiform foregut of kangaroos may allow these animals to maintain food intakes more so than ruminants like sheep, which appear to be limited by fibrous bulk filling the foregut and truncating further ingestion. Using available data on dry matter intake (DMI, g kg(-0.75) d(-1)), ingesta mean retention time (MRT, h), and apparent digestibility, we modelled digestible dry matter intake (DDMI) and digestible energy intake (DEI) by ruminant sheep (Ovis aries) and by the largest marsupial herbivore, the red kangaroo (Macropus rufus). Sheep achieved higher MRTs on similar DMIs, and hence sheep achieved higher DDMIs for any given level of DMI as compared with kangaroos. Interestingly, MRT declined in response to increasing DMI in a similar pattern for both species, and the association between DMI and plant NDF contents did not support the hypothesis that kangaroos are less affected by increasing fibre relative to sheep. However, when DEI was modelled according to DDMIs and dietary energy contents, we show that the kangaroos could meet their daily maintenance energy requirements (MER) at lower levels of DMI and on diets with higher fibre contents compared with sheep, due largely to the kangaroos' lower absolute maintenance and basal energy metabolisms compared with eutherians. These results suggest that differences in the metabolic set-point of different species can have profound effects on their nutritional niche, even when their digestive constraints are similar, as was the case for these ruminant and non

  7. Modelling digestive constraints in non-ruminant and ruminant foregut-fermenting mammals.

    PubMed

    Munn, Adam J; Streich, W Jürgen; Hummel, Jürgen; Clauss, Marcus

    2008-09-01

    It has been suggested that large foregut-fermenting marsupial herbivores, the kangaroos and their relatives, may be less constrained by food intake limitations as compared with ruminants, due mainly to differences in their digestive morphology and management of ingesta particles through the gut. In particular, as the quality of forage declines with increasing contents of plant fibre (cellulose, hemicelluloses and lignin; measured as neutral-detergent fibre, NDF), the tubiform foregut of kangaroos may allow these animals to maintain food intakes more so than ruminants like sheep, which appear to be limited by fibrous bulk filling the foregut and truncating further ingestion. Using available data on dry matter intake (DMI, g kg(-0.75) d(-1)), ingesta mean retention time (MRT, h), and apparent digestibility, we modelled digestible dry matter intake (DDMI) and digestible energy intake (DEI) by ruminant sheep (Ovis aries) and by the largest marsupial herbivore, the red kangaroo (Macropus rufus). Sheep achieved higher MRTs on similar DMIs, and hence sheep achieved higher DDMIs for any given level of DMI as compared with kangaroos. Interestingly, MRT declined in response to increasing DMI in a similar pattern for both species, and the association between DMI and plant NDF contents did not support the hypothesis that kangaroos are less affected by increasing fibre relative to sheep. However, when DEI was modelled according to DDMIs and dietary energy contents, we show that the kangaroos could meet their daily maintenance energy requirements (MER) at lower levels of DMI and on diets with higher fibre contents compared with sheep, due largely to the kangaroos' lower absolute maintenance and basal energy metabolisms compared with eutherians. These results suggest that differences in the metabolic set-point of different species can have profound effects on their nutritional niche, even when their digestive constraints are similar, as was the case for these ruminant and non

  8. The Dutch Brucella abortus monitoring programme for cattle: the impact of false-positive serological reactions and comparison of serological tests.

    PubMed

    Emmerzaal, A; de Wit, J J; Dijkstra, Th; Bakker, D; van Zijderveld, F G

    2002-02-01

    The Dutch national Brucella abortus eradication programme for cattle started in 1959. Sporadic cases occurred yearly until 1995; the last infected herd was culled in 1996. In August 1999 the Netherlands was declared officially free of bovine brucellosis by the European Union. Before 1999, the programme to monitor the official Brucella-free status of bovine herds was primarily based on periodical testing of dairy herds with the milk ring test (MRT) and serological testing of all animals older than 1 year of age from non-dairy herds, using the micro-agglutination test (MAT) as screening test. In addition, serum samples of cattle that aborted were tested with the MAT. The high number of false positive reactions in both tests and the serum agglutination test (SAT) and complement fixation test (CFT) used for confirmation seemed to result in unnecessary blockade of herds, subsequent testing and slaughter of animals. For this reason, a validation study was performed in which three indirect enzyme-linked immunosorbent assays (ELISAs), the CFT and the SAT were compared using a panel of sera from brucellosis-free cattle, sera from experimentally infected cattle, and sera from cattle experimentally infected with bacteria which are known to induce cross-reactive antibodies (Pasteurella, Salmonella, Yersinia, and Escherichia). Moreover, four ELISAs and the MRT were compared using a panel of 1000 bulk milk samples from Brucella-free herds and 12 milk samples from Brucella abortus- infected cattle. It is concluded that the ELISA obtained from ID-Lelystad is the most suitable test to monitor the brucelosis free status of herds because it gives rise to fewer false-positive reactions than the SAT.

  9. Hydrogen-limited growth of hyperthermophilic methanogens at deep-sea hydrothermal vents.

    PubMed

    Ver Eecke, Helene C; Butterfield, David A; Huber, Julie A; Lilley, Marvin D; Olson, Eric J; Roe, Kevin K; Evans, Leigh J; Merkel, Alexandr Y; Cantin, Holly V; Holden, James F

    2012-08-21

    Microbial productivity at hydrothermal vents is among the highest found anywhere in the deep ocean, but constraints on microbial growth and metabolism at vents are lacking. We used a combination of cultivation, molecular, and geochemical tools to verify pure culture H(2) threshold measurements for hyperthermophilic methanogenesis in low-temperature hydrothermal fluids from Axial Volcano and Endeavour Segment in the northeastern Pacific Ocean. Two Methanocaldococcus strains from Axial and Methanocaldococcus jannaschii showed similar Monod growth kinetics when grown in a bioreactor at varying H(2) concentrations. Their H(2) half-saturation value was 66 μM, and growth ceased below 17-23 μM H(2), 10-fold lower than previously predicted. By comparison, measured H(2) and CH(4) concentrations in fluids suggest that there was generally sufficient H(2) for Methanocaldococcus growth at Axial but not at Endeavour. Fluids from one vent at Axial (Marker 113) had anomalously high CH(4) concentrations and contained various thermal classes of methanogens based on cultivation and mcrA/mrtA analyses. At Endeavour, methanogens were largely undetectable in fluid samples based on cultivation and molecular screens, although abundances of hyperthermophilic heterotrophs were relatively high. Where present, Methanocaldococcus genes were the predominant mcrA/mrtA sequences recovered and comprised ∼0.2-6% of the total archaeal community. Field and coculture data suggest that H(2) limitation may be partly ameliorated by H(2) syntrophy with hyperthermophilic heterotrophs. These data support our estimated H(2) threshold for hyperthermophilic methanogenesis at vents and highlight the need for coupled laboratory and field measurements to constrain microbial distribution and biogeochemical impacts in the deep sea.

  10. Indocyanine Green Clearance Varies as a Function of N-Acetylcysteine Treatment in a Murine Model of Acetaminophen Toxicity

    PubMed Central

    Milesi-Hallé, Alessandra; Abdel-Rahman, Susan M.; Brown, Aliza; McCullough, Sandra S.; Letzig, Lynda; Hinson, Jack A.; James, Laura P.

    2011-01-01

    Standard assays to assess acetaminophen (APAP) toxicity in animal models include determination of ALT (alanine aminotransferase) levels and examination of histopathology of liver sections. However, these assays do not reflect the functional capacity of the injured liver. To examine a functional marker of liver injury, the pharmacokinetics of indocyanine green (ICG) were examined in mice treated with APAP, saline, or APAP followed by N-acetylcysteine (NAC) treatment. Male B6C3F1 mice were administered APAP (200 mg/kg IP) or saline. Two additional groups of mice received APAP followed by NAC at 1 or 4 h after APAP. At 24 h, mice were injected with ICG (10 mg/kg IV) and serial blood samples (0, 2, 10, 30, 50 and 75 min) were obtained for determination of serum ICG concentrations and ALT. Mouse livers were removed for measurement of APAP protein adducts and examination of histopathology. Toxicity (ALT values and histology) was significantly increased above saline treated mice in the APAP and APAP/NAC 4 h mice. Mice treated with APAP/NAC 1 h had complete protection from toxicity. APAP protein adducts were increased in all APAP treated groups and were highest in the APAP/NAC 1 h group. Pharmacokinetic analysis of ICG demonstrated that the total body clearance (ClT) of ICG was significantly decreased and the mean residence time (MRT) was significantly increased in the APAP mice compared to the saline mice. Mice treated with NAC at 1 h had ClT and MRT values similar to those of saline treated mice. Conversely, mice that received NAC at 4 h had a similar ICG pharmacokinetic profile to that of the APAP only mice. Prompt treatment with NAC prevented loss of functional activity while late treatment with NAC offered no improvement in ICG clearance at 24 h. ICG clearance in mice with APAP toxicity can be utilized in future studies testing the effects of novel treatments for APAP toxicity. PMID:21145883

  11. Microbial carbon recycling - an underestimated process controlling soil carbon dynamics - Part 1: A long-term laboratory incubation experiment

    NASA Astrophysics Data System (ADS)

    Basler, A.; Dippold, M.; Helfrich, M.; Dyckmans, J.

    2015-10-01

    Independent of its chemical structure carbon (C) persists in soil for several decades, controlled by stabilization and recycling. To disentangle the importance of the two factors on the turnover dynamics of soil sugars, an important compound of soil organic matter (SOM), a 3-year incubation experiment was conducted on a silty loam soil under different types of land use (arable land, grassland and forest) by adding 13C-labelled glucose. The compound-specific isotope analysis of soil sugars was used to examine the dynamics of different sugars during incubation. Sugar dynamics were dominated by a pool of high mean residence times (MRT) indicating that recycling plays an important role for sugars. However, this was not substantially affected by soil C content. Six months after label addition the contribution of the label was much higher for microbial biomass than for CO2 production for all examined land use types, corroborating that substrate recycling was very effective within the microbial biomass. Two different patterns of tracer dynamics could be identified for different sugars: while fucose and mannose showed highest label contribution at the beginning of the incubation with a subsequent slow decline, galactose and rhamnose were characterized by slow label incorporation with subsequently constant levels, which indicates that recycling is dominating the dynamics of these sugars. This may correspond to (a) different microbial growing strategies (r and K-strategist) or (b) location within or outside the cell membrane (lipopolysaccharides vs. exopolysaccharides) and thus be subject of different re-use within the microbial food web. Our results show how the microbial community recycles substrate very effectively and that high losses of substrate only occur during initial stages after substrate addition. This study indicates that recycling is one of the major processes explaining the high MRT observed for many SOM fractions and thus is crucial for understanding the

  12. Hydrogen-limited growth of hyperthermophilic methanogens at deep-sea hydrothermal vents

    PubMed Central

    Ver Eecke, Helene C.; Butterfield, David A.; Huber, Julie A.; Lilley, Marvin D.; Olson, Eric J.; Roe, Kevin K.; Evans, Leigh J.; Merkel, Alexandr Y.; Cantin, Holly V.; Holden, James F.

    2012-01-01

    Microbial productivity at hydrothermal vents is among the highest found anywhere in the deep ocean, but constraints on microbial growth and metabolism at vents are lacking. We used a combination of cultivation, molecular, and geochemical tools to verify pure culture H2 threshold measurements for hyperthermophilic methanogenesis in low-temperature hydrothermal fluids from Axial Volcano and Endeavour Segment in the northeastern Pacific Ocean. Two Methanocaldococcus strains from Axial and Methanocaldococcus jannaschii showed similar Monod growth kinetics when grown in a bioreactor at varying H2 concentrations. Their H2 half-saturation value was 66 μM, and growth ceased below 17–23 μM H2, 10-fold lower than previously predicted. By comparison, measured H2 and CH4 concentrations in fluids suggest that there was generally sufficient H2 for Methanocaldococcus growth at Axial but not at Endeavour. Fluids from one vent at Axial (Marker 113) had anomalously high CH4 concentrations and contained various thermal classes of methanogens based on cultivation and mcrA/mrtA analyses. At Endeavour, methanogens were largely undetectable in fluid samples based on cultivation and molecular screens, although abundances of hyperthermophilic heterotrophs were relatively high. Where present, Methanocaldococcus genes were the predominant mcrA/mrtA sequences recovered and comprised ∼0.2–6% of the total archaeal community. Field and coculture data suggest that H2 limitation may be partly ameliorated by H2 syntrophy with hyperthermophilic heterotrophs. These data support our estimated H2 threshold for hyperthermophilic methanogenesis at vents and highlight the need for coupled laboratory and field measurements to constrain microbial distribution and biogeochemical impacts in the deep sea. PMID:22869718

  13. Development of Sustained Release “NanoFDC (Fixed Dose Combination)” for Hypertension – An Experimental Study

    PubMed Central

    Arora, Anjuman; Shafiq, Nusrat; Jain, Sanjay; Khuller, G. K.; Sharma, Sadhana; Malhotra, Samir

    2015-01-01

    Objectives The present study was planned to formulate, characterize and evaluate the pharmacokinetics of a novel “NanoFDC” comprising three commonly prescribed anti-hypertensive drugs, hydrochlorothiazide (a diuretic), candesartan (ARB) and amlodipine (a calcium channel blocker). Basic Methods The candidate drugs were loaded in Poly (DL-lactide-co-gycolide) (PLGA) by emulsion- diffusion-evaporation method. The formulations were evaluated for their size, morphology, drug loading and in vitro release individually. Single dose pharmacokinetic profiles of the nanoformulations alone and in combination, as a NanoFDC, were evaluated in Wistar rats. Results The candidate drugs encapsulated inside PLGA showed entrapment efficiencies ranging from 30%, 33.5% and 32% for hydrochlorothiazide, candesartan and amlodipine respectively. The nanoparticles ranged in size from 110 to 180 nm. In vitro release profile of the nanoformulation showed 100% release by day 6 in the physiological pH 7.4 set up with PBS (phosphate buffer saline) and by day 4-5 in the intestinal pH 1.2 and 8.0 set up SGF (simulated gastric fluid) and SIF (simulated intestinal fluid) respectively. In pharmacokinetic analysis a sustained-release for 6 days and significant increase in the mean residence time (MRT), as compared to the respective free drugs was noted [MRT of amlodipine, hydrochlorothiazide and candesartan changed from 8.9 to 80.59 hours, 11 to 69.20 hours and 9 to 101.49 hours respectively]. Conclusion We have shown for the first time that encapsulating amlodipine, hydrochlorothiazide and candesartan into a single nanoformulation, to get the “NanoFDC (Fixed Dose Combination)” is a feasible strategy which aims to decrease pill burden. PMID:26047011

  14. Pharmacokinetic and pharmacodynamic modelling of marbofloxacin administered alone and in combination with tolfenamic acid in goats.

    PubMed

    Sidhu, P K; Landoni, M F; Aliabadi, F S; Lees, P

    2010-05-01

    In a four-period cross-over study, the fluoroquinolone antibacterial drug marbofloxacin (MB) was administered to goats intramuscularly (IM) at a dose rate of 2 mg/kg, both alone and in combination with the non-steroidal anti-inflammatory drug tolfenamic acid (TA), also administered IM at a dose rate of 2 mg/kg. Using a tissue cage model of inflammation, based on the irritant actions of carrageenan, the pharmacokinetics (PK) of MB and MB in combination with TA were determined. MB mean values of area under concentration-time curve (AUC) were similar for serum (5.60 microg h/mL), inflamed tissue cage fluid (exudate; 5.32 microg h/mL) and non-inflamed tissue cage fluid (transudate; 4.82 microg h/mL). Values of mean residence time (MRT) of MB in exudate (15.5 h) and transudate (15.8 h) differed significantly from serum MRT (4.23 h). Co-administration of TA did not affect the PK profile of MB. The pharmacodynamics of MB were investigated using a caprine strain of Mannheimia haemolytica. Integration of PK data with ex vivo bacterial time-kill curve data for serum, exudate and transudate provided AUC(24h)/minimum inhibitory concentration (MIC) ratios of 160, 133 and 121 h, respectively, for the strain of organism used. Modelling of the ex vivo time-kill data to the sigmoid E(max) equation provided AUC(24h)/MIC values required for bacteriostatic and bactericidal actions of MB and for virtual eradication of the organism of 27.6, 96.2 and 147.3 h, respectively. Corresponding values for MB+TA were 20.5, 66.5 and 103.0 h. These data were used to predict once daily dosage schedules of MB for subsequent clinical evaluation.

  15. MOSFET dosimetry with high spatial resolution in intense synchrotron-generated x-ray microbeams

    SciTech Connect

    Siegbahn, E. A.; Braeuer-Krisch, E.; Bravin, A.; Nettelbeck, H.; Lerch, M. L. F.; Rosenfeld, A. B.

    2009-04-15

    Various dosimeters have been tested for assessing absorbed doses with microscopic spatial resolution in targets irradiated by high-flux, synchrotron-generated, low-energy ({approx}30-300 keV) x-ray microbeams. A MOSFET detector has been used for this study since its radio sensitive element, which is extraordinarily narrow ({approx}1 {mu}m), suits the main applications of interest, microbeam radiation biology and microbeam radiation therapy (MRT). In MRT, micrometer-wide, centimeter-high, and vertically oriented swaths of tissue are irradiated by arrays of rectangular x-ray microbeams produced by a multislit collimator (MSC). We used MOSFETs to measure the dose distribution, produced by arrays of x-ray microbeams shaped by two different MSCs, in a tissue-equivalent phantom. Doses were measured near the center of the arrays and maximum/minimum (peak/valley) dose ratios (PVDRs) were calculated to determine how variations in heights and in widths of the microbeams influenced this for the therapy, potentially important parameter. Monte Carlo (MC) simulations of the absorbed dose distribution in the phantom were also performed. The results show that when the heights of the irradiated swaths were below those applicable to clinical therapy (<1 mm) the MC simulations produce estimates of PVDRs that are up to a factor of 3 higher than the measured values. For arrays of higher microbeams (i.e., 25 {mu}mx1 cm instead of 25x500 {mu}m{sup 2}), this difference between measured and simulated PVDRs becomes less than 50%. Closer agreement was observed between the measured and simulated PVDRs for the Tecomet MSC (current collimator design) than for the Archer MSC. Sources of discrepancies between measured and simulated doses are discussed, of which the energy dependent response of the MOSFET was shown to be among the most important.

  16. Long term effect of land reclamation from lake on chemical composition of soil organic matter and its mineralization.

    PubMed

    He, Dongmei; Ruan, Honghua

    2014-01-01

    Since the late 1950s, land reclamation from lakes has been a common human disturbance to ecosystems in China. It has greatly diminished the lake area, and altered natural ecological succession. However, little is known about its impact on the carbon (C) cycle. We conducted an experiment to examine the variations of chemical properties of dissolved organic matter (DOM) and C mineralization under four land uses, i.e. coniferous forest (CF), evergreen broadleaf forest (EBF), bamboo forest (BF) and cropland (CL) in a reclaimed land area from Taihu Lake. Soils and lake sediments (LS) were incubated for 360 days in the laboratory and the CO2 evolution from each soil during the incubation was fit to a double exponential model. The DOM was analyzed at the beginning and end of the incubation using UV and fluorescence spectroscopy to understand the relationships between DOM chemistry and C mineralization. The C mineralization in our study was influenced by the land use with different vegetation and management. The greatest cumulative CO2-C emission was observed in BF soil at 0-10 cm depth. The active C pool in EBF at 10-25 cm had longer (62 days) mean residence time (MRT). LS showed the highest cumulative CO2-C and shortest MRT comparing with the terrestrial soils. The carbohydrates in DOM were positively correlated with CO2-C evolution and negatively correlated to phenols in the forest soils. Cropland was consistently an outlier in relationships between DOM chemistry and CO2-evolution, highlighting the unique effects that this land use on soil C cycling, which may be attributed the tillage practices. Our results suggest that C mineralization is closely related to the chemical composition of DOM and sensitive to its variation. Conversion of an aquatic ecosystem into a terrestrial ecosystem may alter the chemical structure of DOM, and then influences soil C mineralization.

  17. The effects of Ramadan fasting on sleep patterns and daytime sleepiness: An objective assessment

    PubMed Central

    BaHammam, Ahmed S.; Alaseem, Abdulrhman M.; Alzakri, Abdulmajid A.; Sharif, Munir M.

    2013-01-01

    Background: Ramadan fasting and its associated lifestyle changes have been linked to changes in sleep and daytime sleepiness. This study was designed to assess the effects of Ramadan fasting on patterns of sleep and daytime sleepiness. Methods: The SenseWear Pro Armband™ was used to assess the duration and distribution of sleep in eight Muslim and eight non-Muslim volunteers during the last week of Shaaban [baseline (BL) and the first (R1) and second (R2) weeks of Ramadan (1430 H)]. OPTALERT™ was used to assess daytime drowsiness objectively using the John Drowsiness Scale (JDS) to assess sleepiness, and a visual reaction time test was used to assess mean reaction time (MRT). Results: The mean ages of Muslims and non-Muslims were 36.25 ± 4.46 and 34.75 ± 3.33 years, respectively. Although the start of work was delayed for Muslims from 0730 to 1000 hours, there was no change in working hours for non-Muslims. During Ramadan, bedtime and wake-up time were delayed, and there was a significant reduction in total sleep time for Muslims (5.91 ± 1.36 hours, 4.95 ± 1.46 hours, and 4.78 ± 1.36 hours during BL, R1, and R2, respectively, P < 0.001), but not for non-Muslims. JDS values in both Muslims and non-Muslims were normal at BL (1.70 ± 1.16 and 1.68 ± 1.07, respectively), and no changes occurred during Ramadan (R1 or R2), indicating no increase in daytime sleepiness. There were no significant changes in MRT during R1 and R2 from BL in either group. Conclusion: Although the sleep cycle of the studied sample shifted during Ramadan among fast observers, there was no objective evidence for increased sleepiness during fasting. PMID:23914215

  18. The influence of triple energy window scatter correction on activity quantification for 1 7 7Lu molecular radiotherapy

    NASA Astrophysics Data System (ADS)

    Robinson, Andrew P.; Tipping, Jill; Cullen, David M.; Hamilton, David

    2016-07-01

    Accurate activity quantification is the foundation for all methods of radiation dosimetry for molecular radiotherapy (MRT). The requirements for patient-specific dosimetry using single photon emission computed tomography (SPECT) are challenging, particularly with respect to scatter correction. In this paper data from phantom studies, combined with results from a fully validated Monte Carlo (MC) SPECT camera simulation, are used to investigate the influence of the triple energy window (TEW) scatter correction on SPECT activity quantification for {{}1 7 7} Lu MRT. Results from phantom data show that; (1) activity quantification for the total counts in the SPECT field-of-view demonstrates a significant overestimation in total activity recovery when TEW scatter correction is applied at low activities (≤slant 200 MBq). (2) Applying the TEW scatter correction to activity quantification within a volume-of-interest with no background activity provides minimal benefit. (3) In the case of activity distributions with background activity, an overestimation of recovered activity of up to 30% is observed when using the TEW scatter correction. Data from MC simulation were used to perform a full analysis of the composition of events in a clinically reconstructed volume of interest. This allowed, for the first time, the separation of the relative contributions of partial volume effects (PVE) and inaccuracies in TEW scatter compensation to the observed overestimation of activity recovery. It is shown, that even with perfect partial volume compensation, TEW scatter correction can overestimate activity recovery by up to 11%. MC data is used to demonstrate that even a localized and optimized isotope-specific TEW correction cannot reflect a patient specific activity distribution without prior knowledge of the complete activity distribution. This highlights the important role of MC simulation in SPECT activity quantification.

  19. Pharmacokinetic comparisons by UPLC-MS/MS of isomer paeoniflorin and albiflorin after oral administration decoctions of single-herb Radix Paeoniae Alba and Zengmian Yiliu prescription to rats.

    PubMed

    Gong, Can; Yang, Hong; Wei, Hai; Qi, Cong; Wang, Chang-Hong

    2015-03-01

    Zengmian Yiliu (ZMYL), a traditional Chinese formula, is designed to improve clinical efficacy and reduce adverse effects in combination with cisplatin in ovarian cancer chemotherapy. In ZMYL, Radix Paeoniae Alba (RPA, made from root of Paeonia lactiflora Pall.) acts as an adjunctive drug in cancer treatment by ameliorating side effects induced by radio- and chemotherapy. The pharmacokinetics differences between isomer albiflorin and paeoniflorin, the main components of RPA, after oral administration decoction of single-herb RPA and ZMYL were compared using a sensitive and accurate UPLC-MS/MS. The results indicate that there are statistically significant differences between the pharmacokinetic parameters: decreasing area under the plasma concentration-time curve (AUC), maximum concentration (Cmax ), elimination rate constant (Ke ) and increasing apparent volume of distribution (Vd ) and clearance (CL) for albiflorin, increasing distribution half-life (T1/2d ) and decreasing elimination half-life (T1/2e ), distribution rate constant (Kd ) and absorption rate constant (Ka ) for paeoniflorin in the ZMYL group compared with the single-herb RPA group. In comparison with albiflorin, the pharmacokinetic parameters of paeoniflorin included significantly increasing mean residence time (MRT) and Vd , decreasing CL and Ke in the single-herb RPA group and increasing MRT and T1/2d and decreasing CL, Ke and Kd in the ZMYL group. Both paeoniflorin and albiflorin are more likely, as the main active ingredients in RPA and ZMYL, to play a variety of pharmacological effects, and herb-herb interactions occur, resulting in different pharmacokinetics of albiflorin and paeoniflorin in RPA and ZMYL. PMID:25042570

  20. Optically erasable samarium-doped fluorophosphate glasses for high-dose measurements in microbeam radiation therapy

    SciTech Connect

    Morrell, B.; Okada, G.; Vahedi, S.; Koughia, C. Kasap, S. O.; Edgar, A.; Varoy, C.; Belev, G.; Wysokinski, T.; Chapman, D.; Sammynaiken, R.

    2014-02-14

    Previous work has demonstrated that fluorophosphate (FP) glasses doped with trivalent samarium (Sm{sup 3+}) can be used as a dosimetric detector in microbeam radiation therapy (MRT) to measure high radiation doses and large dose variations with a resolution in the micrometer range. The present work addresses the use of intense optical radiation at 405 nm to erase the recorded dose information in Sm{sup 3+}-doped FP glass plates and examines the underlying physics. We have evaluated both the conversion and optical erasure of Sm{sup 3+}-doped FP glasses using synchrotron-generated high-dose x-rays at the Canadian Light Source. The Sm-ion valency conversion is accompanied by the appearance of x-ray induced optical absorbance due to the trapping of holes and electrons into phosphorus-oxygen hole (POHC) and electron (POEC) capture centers. Nearly complete Sm{sup 2+} to Sm{sup 3+} reconversion (erasure) may be achieved by intense optical illumination. Combined analysis of absorbance and electron spin resonance measurements indicates that the optical illumination causes partial disappearance of the POHC and the appearance of new POEC. The suggested model for the observed phenomena is based on the release of electrons during the Sm{sup 2+} to Sm{sup 3+} reconversion process, the capture of these electrons by POHC (and hence their disappearance), or by PO groups, with the appearance of new and/or additional POEC. Optical erasure may be used as a practical means to erase the recorded data and permits the reuse of these Sm-doped FP glasses in monitoring dose in MRT.

  1. Die qualitätskontrolle als hilfsmittel zur festlegung der produktionsparameter bei der herstellung von lwr-brennstoffen

    NASA Astrophysics Data System (ADS)

    Sondermann, T.

    1982-04-01

    ZusammenfassungDer bekannte Vorteil des AUC-Verfahrens, ein UO 2-Pulver zu liefern, das ohne Zwischenschritte direkt zu Tabletten verpreβt werden kann, geht mit einer weiteren, weniger bekannten positiven Eigenschaft einher: Mit der Wahl der Produktionsparameter bei der UO 2-Pulverherstellung können die Qualitätsmerkmale der Brennstofftabletten direkt gesteuert werden. Wie umfangreiche Untersuchungen gezeigt haben, besteht ein mathematisch formulierbarer Zusammenhang zwischen den Produktionsparametern und den Pulver-bzw. Tablettenqualitäten. Das so erhaltene mathematische Modell gestattet es nun, exakt die Produktionsparameter einzustellen, die zur gewünschten Qualität führen, wobei gleichzeitig die wirtschaftliche Fahrweise gewählt werden kann.

  2. Cyber-Physical Systems - Wissenschaftliche Herausforderungen Bei Der Entwicklung

    NASA Astrophysics Data System (ADS)

    Broy, Manfred

    Cyber-Physical Systems adressieren die enge Verbindung eingebetteter Systeme zur Überwachung und Steuerung physikalischer Vorgänge mittels Sensoren und Aktuatoren über Kommunikationseinrichtungen mit den globalen digitalen Netzen (dem Cyberspace"). Dieser Typus von Systemen ermöglicht über Wirkketten eine Verbindung zwischen Vorgängen der physischen Realität und den heute verfügbaren digitalen Netzinfrastrukturen. Dies erlaubt vielfältige Applikationen mit hohem wirtschaftlichen Potential, und mit starker Innovationskraft. Die vollständige Ausschöpfung des Potentials erfordert aber gezielte wissenschaftliche Anstrengungen bei der Entwicklung solcher Systeme im Hinblick auf Methodik, Technologie, Kostenbeherrschung und funktionale Angemessenheit.

  3. Victor F. Weisskopf (1908 - 2002): Physikgeschichte

    NASA Astrophysics Data System (ADS)

    Jacobi, Manfred

    2002-11-01

    Universal gebildete und interessierte Menschen sind selten geworden in unserer Zeit. Victor F. Weisskopf war einer von ihnen. Sein geistiger Horizont umfasste nicht nur sein eigentliches Fachgebiet, die Physik, wo er sich durch fundamentale Arbeiten in den Bereichen der Quantenfeldtheorie, der Kern- und Elementarteilchenphysik hervortat. Daneben bildeten Kunst und Musik sowie ein außergewöhnliches Engagement in sozialen und politischen Angelegenheiten die Eckpunkte seines Lebens. Der Einsatz für die Verständigung zwischen den Machtblöcken während des Kalten Krieges war für ihn ebenso selbstverständlich wie das Bedürfnis, die neuen Ideen der Physik einem breiten Publikum nahe zu bringen. Die Wissenschaft erschien ihm als das geeignete Mittel, um zum Wohle der Menschheit zu wirken.

  4. Herausforderungen und Best Practices bei der Speicherung von multi-valued Attributen in LDAP-basierten Verzeichnisdiensten

    NASA Astrophysics Data System (ADS)

    Hommel, Wolfgang; Pluta, Daniel

    LDAP-basierte Verzeichnisdienste unterscheiden sich von relationalen Datenbankmanagementsystemen unter anderem stark bezüglich der Datenmodellierung. Dieser Artikel vertieft eingangs die Herausforderungen bei der LDAP-spezifischen Abbildung von Relationen zwischen mehreren multivalued Attributen. Die Diskussion erfolgt vor dem Hintergrund, dass einerseits Verzeichnisdienste generell nur bedingt zur Speicherung von Relationen geeignet sind und dass andererseits multi-valued Attribute ein mächtiges LDAP-Instrument sind, zu dem es in relationalen Datenbanksystemen keine direkte Entsprechung gibt. Anschließend werden Lösungskonzepte vorgestellt und mögliche Weiterentwicklungen des IntegraTUM-LDAP-Schemas zu deren Umsetzung skizziert, eine exemplarische Implementierung präsentiert und die Ergebnisse der bisherigen Entwicklung des IntegraTUM-Schemas gegenübergestellt.

  5. Simulation und virtuelle Realität

    NASA Astrophysics Data System (ADS)

    von Estorff, Otto; Markiewicz, Marian; Özkan, Ali; Zaleski, Olgierd; Blumrich, Reinhard; Genuit, Klaus; Fiebig, André

    Mit Hilfe akustischer Berechnungen ist es möglich, aufwendige Messungen an Fahrzeugprototypen deutlich zu reduzieren. Dieses Kapitel gibt einen kurzen Überblick über die wichtigsten derzeit verfügbaren Methoden. Dabei wird zunächst auf Elementverfahren, wie die Finite-Elemente-Methode (FEM) und die Boundary-Elemente-Methode (BEM), näher eingegangen. Während diese vor allem im tieffrequenten Bereich eingesetzt werden, kommen bei höheren Frequenzen vermehrt Verfahren zum Einsatz, die auf Energieformulierungen beruhen. Exemplarisch wird hier die Funktionsweise und der Einsatz der Statistischen-Energie-Analyse (SEA) erläutert. Anhand von repräsentativen Beispielen werden die Einsatzmöglichkeiten und Grenzen der verschiedenen Verfahren aufgezeigt, wobei vor allem auch auf Vergleiche zwischen Rechnung und Messung eingegangen wird.

  6. Niob

    NASA Astrophysics Data System (ADS)

    Dettner, H. W.; Franssen, H.; Giesen, K.; Hayes, E. T.; Holetzko, H.; Keysselitz, B.; Loebich, O.; Pelzel, E.; Reinsch, W.; Rostoker, W.; Saur, G.; Volk, K. E.; Wallbaum, H. J.; Borchers, Heinz; Schmidt, Ernst

    Niob — im angelsächsischen Schrifttum vielfach auch als "Columbium" (chemisches Zeichen "Cb") bezeichnet — wurde bis vor wenigen Jahren vorwiegend als Legierungselement in den sog. "Superalloys" oder zur Stabilisierung austenitischer Stähle verwendet. In neuerer Zeit wurden zahlreiche hochwarmfeste Legierungen auf Niobbasis für den Triebwerksbau und korrosionsbeständige Legierungen u. a. für die Verwendung als Hüllenwerkstoff im Reaktorbau entwickelt [D 2, G 1, H 2]. Niob-Uran-Legierungen scheinen sich zur Herstellung von Brennstoffelementen in Reaktoren zu bewähren. Vereinzelt wird Niob auch an Stelle des Tantals für hochwertige Senderöhren, Röntgenröhren und Hochspannungsgleichrichter verwendet. In der Vakuumtechnik dient es als wirksames "bulk getter" (nicht verdampfendes Getter) für den Temperaturbereich zwischen 400 und 900 °C [E 5].

  7. Die Struktur von schlankem Materialfluss mit Lean Production Kanban und Innovationen

    NASA Astrophysics Data System (ADS)

    Scheid, Wolf-Michael

    In der Literatur wird Materialfluss überwiegend in Spezialdisziplinen betrachtet, etwa der Steuerungslogik, der Logistiktechnik oder dem Supply Chain Management. Ein charakterisierendes Merkmal des Materialflusses ist jedoch, dass er sich aus vielfältigen Einzelbausteinen zusammensetzt, die alle harmonisch abgestimmt sein müssen. Die maximal erreichbare Effizienz wird nicht durch Höchstleistungen in dem einen oder anderen Spezialthema bestimmt, sondern durch das schwächste Glied im gesamten komplexen Netzwerk. Den Schnittstellen zwischen den betroffenen Fachbereichen in einem Unternehmen kommt hier eine ganz besondere Bedeutung zu: Erst ein harmonischer Einklang ermöglicht hohe Effektivität. Dies setzt umfassendes Verständnis für interdisziplinäre Notwendigkeiten, ein hohes Maß an Abstimmung mit den operativen Prozessen und letztlich einen einvernehmlichen Umgang und den Respekt vor den Problemstellungen des Anderen voraus.

  8. Eine Beziehung seit 650 Jahren: Universität Wien und Kloster Melk - Katalog zur Sonderausstellung

    NASA Astrophysics Data System (ADS)

    Bruckmüller, Ernst; Niederkorn-Bruck, Meta; Beck, Paul G.; Deibl, Jakob; Deibl, Johannes; Denk, Ulrike; Ellegast, Burkard; Floßmann, Gerhard; Glaßner, Gottfried; Kalteis, Bernadette; Kowarik, Wilfried; Rotheneder, Martin

    2015-04-01

    University of Vienna was founded in 1365 and celebrates its 650 anniversary in 2015. Due to the university's anniversary, the Benedictine abbey of Melk, Austria presents an exhibition, depicting six and half centuries of university history and collaboration between the university as well as the abbey in all disciplines present at medieval universities. The publication describes the historic frame work as well as case-by-case descriptions of displayed manuscripts, prints and artifacts. Die Universität Wien wurde 1365 gegründet und feiert 2015 ihr 650jähriges Bestehen. Aus Anlass dieses Jubiläums präsentiert das Benediktiner Stift Melk eine Ausstellung, in der sechseinhalb Jahrhunderte Universistaetsgeschichte aufgearbeitet werden, sowie die Zusammenarbeit zwischen Universität und Abtei auf allen Themenbereichen, die an mittelalterlichen Universitäten angeboten wurden. Die Publikation bietet eine historische Zusammenfassung sowie eine Detailbeschreibung der ausgestellten Handschriften, Drucke sowie Gegenstände.

  9. Räumliches Hören

    NASA Astrophysics Data System (ADS)

    Blauert, Jens; Braasch, Jonas

    Unsere Hörereignisse (Hörobjekte, Laute) existieren jeweils zu ihrer Zeit an ihrem Ort und sind mit jeweils spezifischen Eigenschaften ausgerüstet. "Räumliches Hören“ als wissenschaftliches Fachgebiet erforscht und beschreibt die Beziehungen zwischen den Orten sowie den räumlichen Ausdehnungen der Hörereignisse untereinander und zu den korrelierten Merkmalen anderer Ereignisse - vorwiegend Schallereignisse, aber z. B. auch physiologische Vorgänge, Ereignisse anderer Sinnesgebiete usw. (s. hierzu Blauert 1974 etc., woraus einige der folgenden Bilder entnommen sind). Übersichtsdarstellungen findet man z. B. auch bei (Bloch 1893, Pierce 1901, von Hornbostel 1926, Trimble 1928, Kietz 1953, Woodworth u. Schlosberg 1954, von Békésy 1960, Aschoff 1963, Keidel 1966, Erulkar 1972, Durlach u. Colburn 1978, Gatehouse 1979, Blauert 1983, Yost u. Gourevitch 1987, Wightman u. Kistler 1993, Begault 1994, Gilkey u. Anderson 1996).

  10. Are you afraid of the dark? Notes on the psychology of belief in histories of science and the occult.

    PubMed

    Sommer, Andreas

    2016-04-01

    Infolge der neuesten Fortschritte innerhalb der Wissenschaftsgeschichte gilt der bis dato gängige Blick auf den inhärenten Konflikt zwischen Wissenschaft und dem Okkulten als hinfällig. Diese Neuerungen innerhalb der Wissenschaft wurden jedoch von der Öffentlichkeit nicht wahrgenommen. Insbesondere die Rekonstruktion der Genese der modernen Psychologie und ihren Verbindungen zu parapsychologischen Forschungen zeigen, dass sich letztere nicht einfach als Ausdruck von metaphysischer Voreingenommenheit verstehen lassen. Um nun einen Ausgleich zu schaffen, werde ich Fälle eines ,‘Willens zum Unglauben‘ diskutieren und davon ausgehend den Vorschlag machen, dass allgemeine psychologische Erklärungen nur dann hilfreich für ein Geschichtsverständnis sind, wenn wir sie in einer symmetrischen Art und Weise anwenden.

  11. Atomic Basic Blocks

    NASA Astrophysics Data System (ADS)

    Scheler, Fabian; Mitzlaff, Martin; Schröder-Preikschat, Wolfgang

    Die Entscheidung, einen zeit- bzw. ereignisgesteuerten Ansatz für ein Echtzeitsystem zu verwenden, ist schwierig und sehr weitreichend. Weitreichend vor allem deshalb, weil diese beiden Ansätze mit äußerst unterschiedlichen Kontrollflussabstraktionen verknüpft sind, die eine spätere Migration zum anderen Paradigma sehr schwer oder gar unmöglich machen. Wir schlagen daher die Verwendung einer Zwischendarstellung vor, die unabhängig von der jeweils verwendeten Kontrollflussabstraktion ist. Für diesen Zweck verwenden wir auf Basisblöcken basierende Atomic Basic Blocks (ABB) und bauen darauf ein Werkzeug, den Real-Time Systems Compiler (RTSC) auf, der die Migration zwischen zeit- und ereignisgesteuerten Systemen unterstützt.

  12. Das Vakuum kommt zu Kräften: Der Casimir-Effekt

    NASA Astrophysics Data System (ADS)

    Lambrecht, Astrid

    2005-03-01

    Die Casimir-Kraft zwischen zwei Spiegeln im Vakuum wird durch Vakuumfluktuationen verursacht. Dieser bedeutende Effekt ermöglicht es, in präzisen Laborversuchen unser Verständnis vom Quantenvakuum zu vertiefen. Eine Vielzahl neuer Experimente setzt dazu moderne Techniken wie die atomare Kraftmikroskopie oder mikroelektromechanische Systeme ein. Auch die theoretischen Modelle werden verbessert, um diese Experimente realistischer nachzubilden. Bislang stimmen die experimentellen Daten gut mit den theoretischen Vorhersagen überein. Da der Casimir-Effekt auf kurzen Distanzen dominieren kann, wird er für die zukünftige Nanotechnik wichtig sein. Der Grundlagenforschung bietet er eine gute Möglichkeit, neue Theorien zur Vereinigung aller Kräfte zu überprüfen.

  13. Rückwärtsintegration - Zu den Verhältnissen Gymnasium, Hochschule und Arbeitswelt

    NASA Astrophysics Data System (ADS)

    Schmid, Gerhard; Heppner, Winfried; Focht, Eva

    In seiner 2007 erschienen Sammlung von Vorträgen und Essays beschäftigt sich Wolfgang Frühwald, mit der Frage "Wieviel Wissen brauchen wir?“ [1] Die Kernproblematik moderner Wissenschaft und Forschung sieht der Autor, emeritierter Ordinarius für Neuere Deutsche Literaturwissenschaft und von 1992 bis 1997 Präsident der Deutschen Forschungsgemeinschaft, einerseits in der zunehmenden Spezialisierung der Wissenschaftsbereiche, andererseits in der Gefahr der Abkoppelung der Naturwissenschaften von den Geisteswissenschaften. Wiederholt plädiert er dafür, über der rasanten Entwicklung beispielsweise in der Biologie und Physik, die historische, gesellschaftliche und besonders die ethische Dimension der Forschung nicht zu übersehen und fordert eine übergeordnete Theorie der Wissenschaft, die nur im Dialog zwischen den einzelnen Fachgebieten zu entwickeln sei.

  14. Measurement of specific medical school stress: translation of the "Perceived Medical School Stress Instrument" to the German language.

    PubMed

    Kötter, Thomas; Voltmer, Edgar

    2013-01-01

    Zielsetzung: Medizinstudierende sind spezifischen Stressoren ausgesetzt. Als Folge der Stressbelastung kommt es bei Medizinstudierenden im Vergleich zu gleichaltrigen Berufstätigen häufiger zu Ängsten, Depressionen und Burn-out. Vitaliano et al. haben bereits 1984 ein 13 Items umfassendes Instrument zur Messung der spezifischen Stressbelastung von Medizinstudierenden, das „Perceived Medical School Stress Instrument“ (PMSS), vorgestellt. Es wurde seitdem im englischsprachigen Bereich breit eingesetzt und validiert. Bislang liegt jedoch keine deutschsprachige Version des Instrumentes vor. Ziel des Projektes war die Übersetzung des PMSS in die deutsche Sprache, um es im Rahmen von Studien im deutschsprachigen Raum einzusetzen.Methodik: Die englischsprachigen Items des PMSS wurden von drei Untersuchern in die deutsche Sprache übersetzt. Die Versionen wurden synoptisch gegenübergestellt und auf dieser Basis wurde für jedes Item eine deutschsprachige Version formuliert. Diese Versionen wurden von Muttersprachlerinnen in die englische Sprache zurückübersetzt. Auf der Basis dieser Rückübersetzungen, eines kognitiven Debriefings an 19 deutschen Medizinstudierenden und einer testtheoretischen Evaluation an 169 deutschen Medizinstudierenden wurden dann die endgültigen deutschsprachigen Formulierungen festgelegt. Ergebnisse: Das PMSS konnte ohne größere Schwierigkeiten in die deutsche Sprache übersetzt werden. Sowohl zwischen den Übersetzungen in die deutsche Sprache als auch zwischen beiden Rückübersetzungen waren die Übereinstimmungen groß. Bei Diskrepanzen erfolgte die Einigung schnell und unkompliziert. Der Einsatz der deutschsprachigen Version erbrachte einen guten Wert für die Reliabilität (Cronbachs Alpha 0,81).Schlussfolgerung: Es steht nun auch für deutschsprachigen Raum ein spezifisches Instrument zur Messung der Stressbelastung von Medizinstudierenden zur Verfügung.

  15. The Questionnaire D-RECT German: Adaptation and testtheoretical properties of an instrument for evaluation of the learning climate in medical specialist training.

    PubMed

    Iblher, Peter; Zupanic, M; Ostermann, T

    2015-01-01

    Zielsetzung: In der Arbeitsgruppe von Boor et al. [1] wurde der Fragebogen D-RECT (Dutch Residency Educational Climate Test) zur Erfassung des Lernklimas in der ärztlichen Weiterbildung entwickelt und validiert. Die deutschsprachige Version (D-RECT-German) wird in der vorliegenden Studie testtheoretisch überprüft.Fragestellung: Ist eine Replikation der Ergebnisse aus der Originalarbeit von Boor et al. als Beleg der Validität des D-RECT möglich?Methodik: Die Befragung erfolgte onlinebasiert mit dem Fragebogen D-RECT-German. Mit Item- und Reliabilitätsanalysen wurden die Kennwerte der 50 Items in 11 Subskalen sowie die interne Konsistenz (Cronbach’s α) ermittelt. Die Validitätsprüfung erfolgte mit einer konfirmatorischen Faktorenanalyse unter Verwendung eines Maximum likelihood basierten Strukturgleichungsmodells.Ergebnisse: Die Itemanalysen dieser Replikationsstudie mit 255 WBA an 17 deutschen Krankenhäusern ergaben für die Items heterogene Trennschärfen, auch die interne Konsistenz der Subskalen zeigte variable Werte für Cronbach’s α zwischen 0.57 und 0.85. In der konfirmatorischen Faktorenanalyse wiesen 6 Items standardisierte Regressionskoeffizienten <0.5 auf die vorgegebenen Dimensionen auf, von denen zwei im Konstrukt „Einstellung der betreuenden Fachärzte“ zu finden waren. Die Korrelationen der Faktoren untereinander wies mit Korrelationen von über 0.7 starke Interdependenzen zwischen den Faktoren „Supervision“, „Coaching“ und „Einstellung der betreuenden Fachärzte“ auf.Schlussfolgerungen: In der Replikationsstudie mit dem D-RECT-German für den deutschsprachigen Raum zeigten sich strukturelle Unterschiede hinsichtlich der faktoriellen Validität, so dass weitere Validierungsstudien für den internationalen Vergleich notwendig sind.

  16. The active participation of German-speaking countries in conferences of the Association for Medical Education in Europe (AMEE) between 2005 and 2013: a reflection of the development of medical education research?

    PubMed

    Raes, Patricia; Bauer, Daniel; Schöppe, Franziska; Fischer, Martin R

    2014-01-01

    Zielsetzung: International gewinnt medizinische Ausbildungsforschung an Bedeutung. Seit Anfang der 2000er ist auch in deutschsprachigen Ländern (D-A-CH) ein steigendes Interesse zu beobachten. In einer kontinuierlichen Steigerung der Publikationszahlen deutscher Autoren in internationalen Fachzeitschriften zum Thema „medizinische Ausbildung“ schlug sich das bisher jedoch nicht nieder. Die vorliegende Arbeit untersucht, ob sich jene Entwicklungen aus der aktiven Teilnahme deutschsprachiger Forscher an den Konferenzen der AMEE ablesen lassen.Methoden: Die Tagungsbände der AMEE-Kongresse von 2005-2013 der Kategorien „Postervorträge“, „Short Communications“, „Research Papers“ und „Plenarvorträge“ wurden auf Beteiligung aus D-A-CH hin untersucht. Im Anschluss wurden die Abstracts einer inhaltlichen Analyse unterzogen und nach Studiendesign, Methodik, Untersuchungsgegenstand und Forschungsthema kategorisiert. Ergebnisse: Von 9446 analysierten Abstracts weisen 549 Beiträge mindestens einen Erst-/Co- oder Letztautor aus D-A-CH auf. Die absolute Zahl der Beiträge pro Kongress schwankt zwischen 44 im Jahr 2010 und 77 im Jahr 2013. Der prozentuale Anteil schwankt zwischen 10,0% in 2005 und 4,1% im Jahr 2010. Seit 2010 stieg die Beteiligung jedoch kontinuierlich an. Die Arbeiten sind zumeist deskriptiver Art (62,7%). Studien zu grundlegenden Fragen des Lehrens und Lernens (clarification studies) sind eher selten (4,0%). Angewandt wurden meist quantitative Methoden (51,9%), um Fragestellungen zu Themen wie Lehr- und Lernmethoden (33,0%), Evaluation und Assessment (22,4%) oder Curriculumsentwicklung (14,4%) zu untersuchen. Untersuchungsgegenstand sind meist Studierende (52,5%).Schlussfolgerung: Die Beitragszahlen aus D-A-CH weisen zu Beginn und am Ende des Untersuchungszeitraums ein Maximum auf. Ein kontinuierlicher Anstieg der aktiven Beteiligung seit 2005 ist nicht zu beobachten. Dieser Umstand spiegelt nicht das steigende Interesse an der

  17. [German translation and adaptation of the uncertainty stress scale high risk pregnancy version III (USS-HRPV) for hospitalised women with high-risk pregnancy].

    PubMed

    Amsler, Marlen; König, Claudia; Ikhilor, Paola Origlia; Cignacco, Eva Lucia

    2014-06-01

    Hintergrund: Medizinisch und gesellschaftlich bedingte Faktoren führen zu einer Zunahme hospitalisierter Frauen mit Risikoschwangerschaft. Die Unvorhersehbarkeit des weiteren Schwangerschaftsverlaufs kann zu Ungewissheit und je nach Bewältigungsstrategie auch zu Stress führen. Ziele: Ziele dieser Studie waren die deutsche Übersetzung und Adaptation der USS-HRPV. Methode: Die Übersetzung in die deutsche Sprache erfolgte mittels Vor- und Rückwärtsübersetzung. Die zwei Phasen umfassende Adaptation wurde mit hospitalisierten Frauen mit Risikoschwangerschaft (n = 24) sowie diplomierten Hebammen (n = 10) durchgeführt und beruht sowohl auf kognitiven Interviews wie auch auf einer Testung der Inhaltsvalidität mittels «Content Validity Index» (CVI). Nach jeder Erhebungsphase wurde das Messinstrument mithilfe von Fachexpertinnen (n = 3) modifiziert. Ergebnisse: Der für jedes Item berechnete CVI (I-CVI) ergab in der ersten Phase für beide Teilstichproben Werte zwischen 0,10 und 1,0, der über das gesamte Messinstrument berechnete CVI (S-CVI/Ave) einen Wert von 0,62 respektive 0,70. Die I-CVI-Werte der hospitalisierten Frauen mit Risikoschwangerschaft der zweiten Phase lagen zwischen 0,17 und 1,0, der S-CVI/Ave betrug 0,73. Insgesamt wurden unter Berücksichtigung aller Daten 44 der ursprünglich 86 Items entfernt und 28 sprachlich verändert. Schlussfolgerungen: Aufgrund der methodischen Vorgehensweise konnte eine solide Ausgangslage für die weiteren Validierungsschritte zur Weiterentwicklung des Messinstrumentes für den deutschsprachigen Raum erarbeitet werden.

  18. Chronostratigraphical investigations on Pleistocene fluvioglacial terraces of NW-Austria

    NASA Astrophysics Data System (ADS)

    Terhorst, B.

    2009-04-01

    of loess loam and redeposited material. However, four to five interglacial paleosols are developed inside the studied sequences. Paleomagnetical investigations are leading to the assumption that different Middle Pleistocene excursions could provide chronological data in the future. Terhorst, B., 2007. Korrelation von mittelpleistozänen Löß-/Paläobodensequenzen in Oberösterreich mit einer marinen Sauerstoffisotopenkurve. E & G, Quaternary Science Journal, 56/3: 172 - 185. Terhorst, B., Frechen, M. and Reitner, J., 2002 Chronostratigraphische Ergebnisse aus Lößprofilen der Inn- und Traun-Hochterrassen in Oberösterreich. - Z. Geomorph. N.F., Suppl.-Bd., 127: 213 -232, Berlin, Stuttgart (Gebr. Bornträger).

  19. Biochar carbon sequestration and downward translocation in contrasting soils under field conditions in Australia

    NASA Astrophysics Data System (ADS)

    Pal Singh, Bhupinder; Fang, Yunying; Boersma, Mark; Matta, Pushpinder; Van Zwieten, Lukas; Macdonald, Lynne

    2014-05-01

    Carbon (C) sequestration potential of biochar depends on its stability and stabilisation of native or added organic C in soil. However, the processes of biochar degradation, fate in soil organic matter pools, and downward translocation in the soil profile, and the influence of biochar on emissions or stabilisation of native organic C sources are poorly understood under field conditions. An Eucalyptus saligna green-waste biochar (δ13C -36.6o; total C 66.8%) produced by slow pyrolysis at 450° C was applied at 29.2 t ha-1 to 10-cm depth in circular (0.66-m diameter) micro-plots, encompassing three soils [Tenosol, Dermosol and Ferrosol (Australian Soil Classification); Arenosol, Planosol, Ferralsol (approximate WRB Classification] under contrasting pasture systems across New South Wales and Tasmania (Australia). The aims of this study were to (i) monitor the fate of biochar C in respired CO2 and quantify biochar stability and stabilisation under field conditions, (ii) determine the influence of biochar on native soil C emissions, and (iii) track downward migration of the surface (0-10 cm) applied biochar over a 1-year period. We also periodically monitored the impact of biochar on microbial biomass carbon (MBC) and aboveground biomass production. The soils were separated into light and heavy C fractions and the C recovery of applied biochar C was calculated at 0-8, 8-12, 12-20 and 20-30 cm depths. Biochar C mineralisation rates were generally higher, albeit fluctuated widely, in the first 3 to 4 months. Over the first 7 months, the proportion of added biochar C mineralised in soils ranged between 1.4 and 5.5% and followed the sequence: Tenosol < Dermosol < Ferrosol. The mean residence time (MRT) of biochar ranged from 29 and 70 years. These values of MRT should be treated as highly conservative values, as they mainly reflect the MRT of relatively labile C components in biochar. The cumulative CO2-C emission over the 7-month period from native soil and plant sources

  20. Human serum butyrylcholinesterase: in vitro and in vivo stability, pharmacokinetics, and safety in mice.

    PubMed

    Saxena, Ashima; Sun, Wei; Luo, Chunyuan; Doctor, Bhupendra P

    2005-12-15

    The use of exogenously administered cholinesterases (ChEs) as bioscavengers of highly toxic organophosphate (OP) nerve agents is now sufficiently well documented to make them a highly viable prophylactic treatment against this potential threat. Of the ChEs evaluated so far, human serum butyrylcholinesterase (HuBChE) is most suitable for human use. A dose of 200 mg (3 mg/kg) of HuBChE is envisioned as a prophylactic treatment in humans that can protect from an exposure of up to 2 x LD50 of soman. In addition to its use as a prophylactic for a variety of wartime scenarios, including covert actions, it also has potential use for first responders (civilians) reacting to terrorist nerve gas release. We recently, developed a procedure for the large-scale purification of HuBChE, which yielded approximately 6 g of highly purified enzyme from 120 kg of Cohn fraction IV-4. The enzyme had a specific activity of 700-750 U/mg and migrated as a single band on SDS-PAGE. To provide data for initiating an investigational new drug (IND) application for the use of this enzyme as a bioscavenger in humans, we established its pharmacokinetic properties, examined its safety in mice, and evaluated its shelf life at various temperatures. In mice administered various doses up to 90 mg/kg, enzyme activity reached peak levels in circulation at 10 and 24 h following i.p. and i.m. injections, respectively. The enzyme displayed a mean residence time (MRT) of 40-50 h, regardless of the route of administration or dose of injected enzyme. Mice were euthanized 2 weeks following enzyme administration and tissues were examined grossly or microscopically for possible toxic effects. Results suggest that HuBChE does not exhibit any toxicity in mice as measured by general observation, serum chemistry, hematology, gross or histologic tissue changes. The shelf life of this enzyme stored at 4, 25, 37, and 45 degrees C was determined in lyophilized form. The enzyme was found to be stable when stored in

  1. [Determination of plasma concentration of quercetin, kaempferid and isorhamnetin in Hippophae rhamnoides extract by HPLC-MS/MS and pharmacokinetics in rats].

    PubMed

    Liu, Yu; Yang, Juan; Tuo, Yang-ling; Wei, Ting; Zeng, Yong; Wang, Ping; Meng, Xian-li

    2015-10-01

    To establish an HPLC-MS/MS method for the analysis of quercetin, kaempferid and isorhamnetin in rats plasma and study its pharmamacokinetics after an intragastrical administration of Hippophae rhamnoides extracts. Five healthy male Sprague-Dawley (SD) rats were given single doses of H. rhamnoides extracts (quercetin 26.35 mg x kg(-1), kaempferid 4.040 mg x kg(-1), isorhamnetin 31.37 mg x kg(-1)), and then their orbital sinus blood samples were collected at different time points. The drug plasma concentration of the three flavonoids was determined by HPLC-MS/MS method. After that, the main pharmacokinetics parameters were calculated by using Kinetica 5. 0. 11 software. The methodological test showed that the linear concentration ranges of quercetin, kaempferid and isorhamnetin were 7.500-600.0 μg x L(-1) (R2 = 0.998 5), 1.000-80.00 μg x L(-1) (R2 = 0.998 5 ) and 10.00-800.0 μg x L(-1) (R2 = 0.998 0), respectively. The inner and inter-days precisions were both less than 14.0%. The plasma samples showed a good stability and consistency with the requirement of biological sample analysis after the samples were frozen once and placed at - 20 degrees C for 15 d and room temperature for 6 h and the treated analytes were placed at -20 degrees C for 24 h. For quercetin, the pharmacokinetic parameter t(½β), AUC(0-∞), MRT(0.∞), C.(max) and T(max) were (113.3 ± 19.37) min, (12 542.14 ± 3 504.05) μg x h x L(-1), (119.6 ± 13.29) h, (164.6 ± 27.33) μg x L(-1) and (5.199 ± 0.840 3) h, respectively. For kaempferid, the pharmacokinetic parameters t(½β), AUC(0-t), MRT(0-∞), C(max) and T(max) were (79.85 ± 17.15) min, (934.51 ± 94.59) μg x h x L(-1), (81.50 ± 13.75) h, (80.15 ± 14.24) μg x L(-1) and (3.827 ± 0.902 7) h, respectively. For isorhamnetin, the pharmacokinetic parameters t1,2,, AUC(0-t), MRT(0-∞), C(max) and T(max) were (118.3 ± 20.73) min, (26 067.77 ± 4 124.60) μg x h x L(-1), (129.0 ± 16.30) h, (269.6 ± 29.32) μg x L(-1) and (6.513 ± 1

  2. Cyclosporine pharmacokinetics in pancreas transplant recipients.

    PubMed

    Munda, R; Schroeder, T J; Pedersen, S A; Clardy, C W; Wadhwa, N K; Myre, S A; Stephens, G W; Pesce, A J; Alexander, J W; First, M R

    1988-04-01

    Ten CsA pharmacokinetic studies were performed on five pancreas transplant recipients to determine proper doses and dosing intervals. These cadaver pancreas transplants were performed with exocrine ductal drainage into the urinary tract through a bladder anastomosis in four cases and into the bowel in one case. Four CsA pharmacokinetic studies were performed on diabetic renal transplant recipients and an additional six studies were performed while with pancreas transplant patients taking metoclopramide in an effort to enhance absorption of CsA. Mean CsA dose was 3.7 mg/kg/dose (range 2.1 to 7.5 mg/kg/dose). All patients but one were on twice daily dosing intervals yielding an average daily dose of 7.4 mg/kg/d. Noncompartmental pharmacokinetic analyses were used. The adequacy of a 1-, 2-, or 3-exponential model was determined by breakpoint analysis of the log concentration v time curve using the F statistic. The terminal rate constant was calculated by nonlinear regression analysis. The AUC and AUMC were calculated by the trapezoidal method with exponential extrapolation and these were used to calculate the MRT and Vdss. The unknown fractional absorption, F, was used to correct the oral data. The average CsA concentration maximum (Cmax) was 528 ng/mL with an average time to maximum concentration (Tmax) of 4.7 hours, a mean residence time of 7.75 hours, with a Vdss/%F of 9.61 L/kg in the pancreas transplant recipients. Additional studies of six patients receiving metoclopramide with CsA revealed an average Cmax of 723 ng/mL, an average Tmax of 2.3 hours, an average MRT of 6.08 hours, and an average Vdss/%F of 5.7% L/kg. These results indicate that coexistent gastroparesis in diabetic recipients of either pancreatic or renal transplants may result in reduced bioavailability of CsA. PMID:3284095

  3. Skeletal muscle microvascular oxygenation dynamics in heart failure: exercise training and nitric oxide-mediated function.

    PubMed

    Hirai, Daniel M; Copp, Steven W; Holdsworth, Clark T; Ferguson, Scott K; McCullough, Danielle J; Behnke, Bradley J; Musch, Timothy I; Poole, David C

    2014-03-01

    Chronic heart failure (CHF) impairs nitric oxide (NO)-mediated regulation of skeletal muscle O2 delivery-utilization matching such that microvascular oxygenation falls faster (i.e., speeds PO2mv kinetics) during increases in metabolic demand. Conversely, exercise training improves (slows) muscle PO2mv kinetics following contractions onset in healthy young individuals via NO-dependent mechanisms. We tested the hypothesis that exercise training would improve contracting muscle microvascular oxygenation in CHF rats partly via improved NO-mediated function. CHF rats (left ventricular end-diastolic pressure = 17 ± 2 mmHg) were assigned to sedentary (n = 11) or progressive treadmill exercise training (n = 11; 5 days/wk, 6-8 wk, final workload of 60 min/day at 35 m/min; -14% grade downhill running) groups. PO2mv was measured via phosphorescence quenching in the spinotrapezius muscle at rest and during 1-Hz twitch contractions under control (Krebs-Henseleit solution), sodium nitroprusside (SNP; NO donor; 300 μM), and N(G)-nitro-l-arginine methyl ester (L-NAME, nonspecific NO synthase blockade; 1.5 mM) superfusion conditions. Exercise-trained CHF rats had greater peak oxygen uptake and spinotrapezius muscle citrate synthase activity than their sedentary counterparts (p < 0.05 for both). The overall speed of the PO2mv fall during contractions (mean response time; MRT) was slowed markedly in trained compared with sedentary CHF rats (sedentary: 20.8 ± 1.4, trained: 32.3 ± 3.0 s; p < 0.05), and the effect was not abolished by L-NAME (sedentary: 16.8 ± 1.5, trained: 31.0 ± 3.4 s; p > 0.05). Relative to control, SNP increased MRT in both groups such that trained CHF rats had slower kinetics (sedentary: 43.0 ± 6.8, trained: 55.5 ± 7.8 s; p < 0.05). Improved NO-mediated function is not obligatory for training-induced improvements in skeletal muscle microvascular oxygenation (slowed PO2mv kinetics) following contractions onset in rats with CHF.

  4. Radiography of magnetically-driven implosions of initially solid beryllium cylindrical shells for equation-of-state studies at the Z pulsed-power facility

    NASA Astrophysics Data System (ADS)

    McBride, Ryan

    2011-06-01

    The Z accelerator delivers approximately 4-MV, 26-MA electrical pulses with adjustable current rise times of 100--600 ns, as well as adjustable pulse waveforms. The magnetic pressure produced is used for various applications, including magnetically-driven implosions. The Z-Beamlet Laser (ZBL) is a pulsed (0.3-1.5 ns), multi-kJ, TW-class Nd:glass laser system that provides x-ray radiography capabilities for Z experiments. This talk focuses primarily on the radiography diagnostic used to study the magnetically-driven implosions of initially solid cylindrical shells (also referred to as ``liners''). Specifically, we discuss the 6.151-keV monochromatic backlighting system and its use in obtaining radiographs of imploding beryllium (Be) liners. The high transmission efficiency of 6.151-keV photons in Be allowed us to obtain radiographs with finite transmission throughout the radial extent of the imploding liners. Abel inverting these data, we have obtained time-resolved measurements of the imploding liner's density as a function of both axial and radial location throughout the field of view. These data are allowing us to study magneto-Rayleigh-Taylor (MRT) growth for inertial-confinement-fusion applications, as well as compression-wave propagation for equation-of-state studies (see talks by R.L. Lemke and M.R. Martin). Additionally, Z's pulse-shaping capabilities have enabled us to obtain data for both shock- and quasi-isentropically-compressed Be. Example data from MRT, shock-compression, and quasi-isentropic-compression experiments will be shown. We will also discuss planned upgrades to 25-keV radiography that will allow us to study materials with opacities beyond that of beryllium. This work was done in collaboration with R.W. Lemke, M.R. Martin, J.-P. Davis, M.D. Knudson, D.B. Sinars, S.A. Slutz, C.A. Jennings, M.E. Cuneo, D.G. Flicker, and M.C. Herrmann. Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed-Martin company, for the US

  5. [Pharmacokinetics and relative bioavailability of THC and THC-solid dispersion orally to mice at single dose].

    PubMed

    Liao, Li; Hua, Hua; Zhao, Jun-Ning; Luo, Heng; Yang, An-Dong

    2014-03-01

    To establish a fast sensitive, reproducible LC-MS/MS method to study pharmacokinetic properties of THC, and compare relative bioavailability of THC and its solid dispersion in mice. 200 mice were divided randomly into two groups, and administered orally with THC and THC-solid dispersion after fasting (calculate on THC:400 mg x kg(-1)), used HPLC-MS/MS method to determine the THC concentration of each period at the following times: baseline ( predose ), 15, 30, 45 min, 1, 1.5, 2, 3, 4, 6, 24 h after dosing. Calculating the pharmacokinetic parameters according to the C-t curv, and then use the Phoenix WinNonlin software for data analysis. The calibration curves were linear over the range 9.06-972 microg x L(-1) for THC (R2 = 0.999). The limit of detection (LOD) was 0.7 microg x L(-1), respectively. The average extraction recoveries for THC was above 75%, The methodology recoveries were between 79% and 108%. The intra-day and inter-day RSD were less than 13%, the stability test showed that the plasma samples was stable under different conditions (RSD < 15%). The precision, accuracy, recovery and applicability were found to be adequate for pharmacokinetic studies. Pharmacokinetic parameters of THC and THC-solid dispersion orally to mice shows as fllows: T(max), were 60 and 15 min, AUC(0-t) were 44 500.43 and 57 497.81 mg x L(-1) x min, AUC(0-infinity) were 51 226.00 and 68 031.48 mg x L(-1) x min, MRT(0-infinity) were 596.915 6, 661.747 7 min, CL(z)/F were 0.007 809 and 0.005 88 L x min(-1) x kg(-1). Compared with THC, the MRT and t1/2 of the THC-solid dispersion were all slightly extended, the t(max) was significantly reduced, AUC(0-24 h), AUC(0-infinity) and C(max) were all significantly higher, the relative bioavailability of THC-solid dispersion is 1.34 times of THC. The results of the experiment shows that the precision, accuracy, recovery and applicability were found to be adequate for the pharmacokinetic studies. After oral administration to mice, the relative

  6. Dynamics of noncovalent interactions in all-α and all-β class proteins: implications for the stability of amyloid aggregates.

    PubMed

    Jain, Alok; Sankararamakrishnan, Ramasubbu

    2011-12-27

    A fully folded functional protein is stabilized by several noncovalent interactions. When a protein undergoes conformational motions, the existing noncovalent interactions may be maintained. They may also break or new interactions may be formed. Knowledge of the dynamical nature of the different types of noncovalent interactions is extremely important to understand the structural stability, function, and folding of a protein. There are experimental limitations to investigate the dynamics of different noncovalent interactions simultaneously in a biomolecule. We have carried out molecular dynamics simulations on four different proteins, two belonging to all-α class proteins and the other two are representatives of all-β class proteins. The dynamical nature of eight different noncovalent interactions was studied by monitoring the maximum residence time (MRT) and lifetime (LT). The conventional hydrogen bonds are the dominant interactions in all four proteins, and the majority of those formed between the main-chain atoms were maintained during most of the simulation time with MRT greater than 10 ns. Such interactions with more than 1 ns lifetime provide stability to the secondary structures, and hence they are responsible for the overall stability of the protein. The weak C-H···O hydrogen bond is the next major type of interactions. However, a large number of such interactions are observed between the main-chain atoms only in all-β proteins as interstrand interactions, and, surprisingly, they are observed during most part of the simulation although their average lifetime is only about 20 to 30 ps. The strong cation···π and salt-bridge interactions are present few in number. However, in many cases they are almost uninterrupted indicating the higher strength of these interactions. Four other interactions involving the π-electron cloud of aromatic rings are very small in number, and, in many cases, their presence is not maintained throughout the simulation. Our

  7. Plasma achiral and chiral pharmacokinetic behaviour of intravenous oxfendazole co-administered with piperonyl butoxide in sheep.

    PubMed

    Sánchez, S; Small, J; Jones, D G; McKellar, Q A

    2002-02-01

    Co-administration of piperonyl butoxide (PB) potentiates fenbendazole (FBZ) in small ruminants. The resultant increase in bioavailability of FBZ and its metabolite oxfendazole (OFZ) has important implications for the efficacy of these drugs against benzimidazole (BZD)-resistant strains of Teladorsagia circumcincta. This study evaluated the racemic (achiral) and enantiomeric (chiral) plasma disposition kinetics of OFZ and its metabolites after the co-administration of PB and OFZ in sheep. Six 6-8-month-old, parasite-free, female Dorset sheep (30-40 kg) were used in a two-phase crossover experiment. In phase I, three sheep received 30 mg/kg PB orally, followed by a single intravenous (i.v.) injection of OFZ at 5 mg/kg. The other three animals were treated similarly except that 5 mL of water replaced PB. In phase 2, treatments for the two groups were reversed and were given 14 days after the initiation of phase I. Three analytes OFZ, FBZ and fenbendazole sulphone (FBZSO(2)) were recovered in plasma up to 48 h post-treatment in both experimental groups. Achiral and chiral pharmacokinetic (PK) profiles for OFZ, after the co-administration of PB, were characterized by a significantly greater area under the concentration--time curve (AUC) and a longer mean residence time (MRT). Chiral OFZ distribution ratios were comparable in both treatment groups. Piperonyl butoxide treatment markedly influenced the plasma PK profiles for FBZ and FBZSO(2) following OFZ administration. Production of FBZ was enhanced as reflected by increased (> 60%) AUC, delayed T(max) and a significantly delayed (> 45%) elimination (t(1/2)(el)). Although AUC values for FBZSO(2) were not significantly different between groups, this metabolite was depleted more slowly from plasma (t(1/2)(el) > 60% and MRT > 42%) following PB treatment. This study demonstrated that PB co-administration is associated with an inhibition of OFZ biotransformation, as evidenced by the significantly higher plasma concentrations

  8. Dynamic Angular Control Of Thermal Therapy With Stationary Multi-Sectored Tubular Ultrasound Applicators Under MR Temperature Monitoring

    NASA Astrophysics Data System (ADS)

    Kinsey, Adam M.; Diederich, Chris J.; Nau, William H.; Ross, Anthony B.; Butts Pauly, Kim; Rieke, Viola; Sommer, Graham

    2006-05-01

    Multi-sectored ultrasound heating applicators with dynamic angular and longitudinal control of heating profiles are being investigated for the thermal treatment of tumors in sites such as prostate, uterus, and brain. Multi-sectored tubular ultrasound transducers with independent sector power control were incorporated into interstitial and transurethral applicators and provided dynamic angular control of a heating pattern without requiring device manipulation during treatment. Acoustic beam measurements of each applicator type demonstrated a 35-40° acoustic dead zone between each independent sector, with negligible mechanical or electrical coupling. Despite the acoustic dead zone between sectors, simulations and experiments under MR temperature (MRT) monitoring showed that the variance from the maximum lesion radius (scalloping) with all elements activated on a transducer was minimal and did not affect conformal heating of a target area. A biothermal model with a multi-point controller was used to adjust the applied power and treatment time of individual transducer segments as the tissue temperature changed in simulations of thermal lesions with both interstitial and transurethral applicators. Transurethral ultrasound applicators for benign prostatic hyperplasia (BPH) treatment with either three or four sectors conformed a thermal dose to a simulated target area in the angular and radial dimensions. The simulated treatment was controlled to a maximum temperature of 85°C, and had a maximum duration of 5 min when power was turned off as the 52°C temperature contour reach a predetermined control point for each sector in the tissue. Experiments conducted with multi-sectored applicators under MRT monitoring showed thermal ablation and hyperthermia treatments had little or no border `scalloping', conformed to a pretreatment target area, and correlated very well with the simulated thermal lesions. The radial penetration of the heat treatments in tissue with interstitial

  9. Matching tracer selection to georeservoir typology - A note on geothermal reservoir classification

    NASA Astrophysics Data System (ADS)

    Ghergut, Julia; Behrens, Horst; Licha, Tobias; Sauter, Martin

    2013-04-01

    distribution (with mean residence time MRT) correlates differently with thermal lifetime: the more pronounced the petrothermal character (with effective aperture w), the more the quadratic term (proportional to Dth*MRT2/w2) will prevail within thermal lifetime. It therefore turns out that thermo-sensitive tracers are less useful (roughly speaking) in petrothermal, than in aquifer-based reservoirs; whereas sorptive tracers prove more useful in petrothermally-dominated, than in aquifer-based reservoirs. Acknowledgement: This study was conducted within task unit G6 of the project gebo ('Geothermal Energy and High-Performance Drilling'), funded by the Lower-Saxonian Ministry of Science and Culture and by Baker Hughes (Celle), Germany.

  10. Spacecraft Internal Acoustic Environment Modeling

    NASA Technical Reports Server (NTRS)

    Chu, SShao-sheng R.; Allen, Christopher S.

    2009-01-01

    carried out by acquiring octave band microphone data simultaneously at ten fixed locations throughout the mockup. SPLs (Sound Pressure Levels) predicted by our SEA model match well with measurements for our CM mockup, with a more complicated shape. Additionally in FY09, background NC noise (Noise Criterion) simulation and MRT (Modified Rhyme Test) were developed and performed in the mockup to determine the maximum noise level in CM habitable volume for fair crew voice communications. Numerous demonstrations of simulated noise environment in the mockup and associated SIL (Speech Interference Level) via MRT were performed for various communities, including members from NASA and Orion prime-/sub-contractors. Also, a new HSIR (Human-Systems Integration Requirement) for limiting pre- and post-landing SIL was proposed.

  11. A mass-conserving lattice Boltzmann method with dynamic grid refinement for immiscible two-phase flows

    NASA Astrophysics Data System (ADS)

    Fakhari, Abbas; Geier, Martin; Lee, Taehun

    2016-06-01

    A mass-conserving lattice Boltzmann method (LBM) for multiphase flows is presented in this paper. The proposed LBM improves a previous model (Lee and Liu, 2010 [21]) in terms of mass conservation, speed-up, and efficiency, and also extends its capabilities for implementation on non-uniform grids. The presented model consists of a phase-field lattice Boltzmann equation (LBE) for tracking the interface between different fluids and a pressure-evolution LBM for recovering the hydrodynamic properties. In addition to the mass conservation property and the simplicity of the algorithm, the advantages of the current phase-field LBE are that it is an order of magnitude faster than the previous interface tracking LBE proposed by Lee and Liu (2010) [21] and it requires less memory resources for data storage. Meanwhile, the pressure-evolution LBM is equipped with a multi-relaxation-time (MRT) collision operator to facilitate attainability of small relaxation rates thereby allowing simulation of multiphase flows at higher Reynolds numbers. Additionally, we reformulate the presented MRT-LBM on nonuniform grids within an adaptive mesh refinement (AMR) framework. Various benchmark studies such as a rising bubble and a falling drop under buoyancy, droplet splashing on a wet surface, and droplet coalescence onto a fluid interface are conducted to examine the accuracy and versatility of the proposed AMR-LBM. The proposed model is further validated by comparing the results with other LB models on uniform grids. A factor of about 20 in savings of computational resources is achieved by using the proposed AMR-LBM. As a more demanding application, the Kelvin-Helmholtz instability (KHI) of a shear-layer flow is investigated for both density-matched and density-stratified binary fluids. The KHI results of the density-matched fluids are shown to be in good agreement with the benchmark AMR results based on the sharp-interface approach. When a density contrast between the two fluids exists, a

  12. Recent advances in theoretical and numerical studies of wire array Z-pinch in the IAPCM

    SciTech Connect

    Ding, Ning Zhang, Yang Xiao, Delong Wu, Jiming Huang, Jun Yin, Li Sun, Shunkai Xue, Chuang Dai, Zihuan Ning, Cheng Shu, Xiaojian Wang, Jianguo Li, Hua

    2014-12-15

    Fast Z-pinch has produced the most powerful X-ray radiation source in laboratory and also shows the possibility to drive inertial confinement fusion (ICF). Recent advances in wire-array Z-pinch researches at the Institute of Applied Physics and Computational Mathematics are presented in this paper. A typical wire array Z-pinch process has three phases: wire plasma formation and ablation, implosion and the MRT instability development, stagnation and radiation. A mass injection model with azimuthal modulation coefficient is used to describe the wire initiation, and the dynamics of ablated plasmas of wire-array Z-pinches in (r, θ) geometry is numerically studied. In the implosion phase, a two-dimensional(r, z) three temperature radiation MHD code MARED has been developed to investigate the development of the Magneto-Rayleigh-Taylor(MRT) instability. We also analyze the implosion modes of nested wire-array and find that the inner wire-array is hardly affected before the impaction of the outer wire-array. While the plasma accelerated to high speed in the implosion stage stagnates on the axis, abundant x-ray radiation is produced. The energy spectrum of the radiation and the production mechanism are investigated. The computational x-ray pulse shows a reasonable agreement with the experimental result. We also suggest that using alloyed wire-arrays can increase multi-keV K-shell yield by decreasing the opacity of K-shell lines. In addition, we use a detailed circuit model to study the energy coupling between the generator and the Z-pinch implosion. Recently, we are concentrating on the problems of Z-pinch driven ICF, such as dynamic hohlraum and capsule implosions. Our numerical investigations on the interaction of wire-array Z-pinches on foam convertors show qualitative agreements with experimental results on the “Qiangguang I” facility. An integrated two-dimensional simulation of dynamic hohlraum driven capsule implosion provides us the physical insights of wire

  13. Stability of spironolactone in rat plasma: strict temperature control of blood and plasma samples is required in rat pharmacokinetic studies.

    PubMed

    Tokumura, Tadakazu; Muraoka, Atsushi; Masutomi, Takashi; Machida, Yoshiharu

    2005-06-01

    The stability of spironolactone (SPN) in rat plasma was studied and its degradation was found to be an apparent first-order reaction. The apparent first-order rate constants (k(obs)) at 37, 23.5 and 0 degrees C were 3.543+/-0.261 (h-1, mean+/-S.D., n=3), 6.278+/-0.045 (x10(-1) h-1), and 7.336+/-0.843 (x10(-2) h-1), respectively. The half-lives were 0.20 h, 1.10 h, and 9.53 h. The degradation rate of SPN in rat plasma was markedly decreased when NaF, an esterase inhibitor, was added to the plasma, and the degradation was catalyzed by esterase in the plasma. These results indicated that not only plasma but also blood and serum samples in rat pharmacokinetic studies should be cooled to 0 degrees C, the temperature maintained, and treated as soon as possible. In pharmacokinetic studies reported previously, the temperature control of plasma, blood, and serum samples was not described. The pharmacokinetic study in rats after intravenous administration of SPN at 20 mg/kg was performed with strict temperature control of plasma and blood samples. The AUC, MRT, CL and Vd(ss) values (mean+/-S.E. of 4 rats) for SPN were 4100.8+/-212.9 ng h/ml, 0.29+/-0.01 h, 4915.7+/-248.0 ml/h/kg, and 1435.4+/-48.4 ml/kg, respectively. The AUC value was much larger than that previously reported. The AUC, MRT, Cmax and Tmax values (mean+/-S.E. of 4 rats) of canrenone, an active metabolite of SPN, after the administration of SPN were 4196.1+/-787.5 ng h/ml, 1.99+/-0.13 h, 1546.3+/-436.4 ng/ml and 1.0+/-0.0 h, respectively. This AUC value was almost identical to the value previously reported. PMID:15930762

  14. Differential Responses of Post-Exercise Recovery of Leg Blood Flow and Oxygen Uptake Kinetics in HFpEF versus HFrEF

    PubMed Central

    Thompson, Richard B.; Pagano, Joseph J.; Mathewson, Kory W.; Paterson, Ian; Dyck, Jason R.; Kitzman, Dalane W.; Haykowsky, Mark J.

    2016-01-01

    The goals of the current study were to compare leg blood flow, oxygen extraction and oxygen uptake (VO2) after constant load sub-maximal unilateral knee extension (ULKE) exercise in patients with heart failure with reduced ejection fraction (HFrEF) compared to those with preserved ejection fraction (HFpEF). Previously, it has been shown that prolonged whole body VO2 recovery kinetics are directly related to disease severity and all-cause mortality in HFrEF patients. To date, no study has simultaneously measured muscle-specific blood flow and oxygen extraction post exercise recovery kinetics in HFrEF or HFpEF patients; therefore it is unknown if muscle VO2 recovery kinetics, and more specifically, the recovery kinetics of blood flow and oxygen extraction at the level of the muscle, differ between HF phenotypes. Ten older (68±10yrs) HFrEF (n = 5) and HFpEF (n = 5) patients performed sub-maximal (85% of maximal weight lifted during an incremental test) ULKE exercise for 4 minutes. Femoral venous blood flow and venous O2 saturation were measured continuously from the onset of end-exercise, using a novel MRI method, to determine off-kinetics (mean response times, MRT) for leg VO2 and its determinants. HFpEF and HFrEF patients had similar end-exercise leg blood flow (1.1±0.6 vs. 1.2±0.6 L/min, p>0.05), venous saturation (42±12 vs. 41±11%, p>0.05) and VO2 (0.13±0.08 vs. 0.11±0.05 L/min, p>0.05); however HFrEF had significantly delayed recovery MRT for flow (292±135sec. vs 105±63sec., p = 0.004) and VO2 (95±37sec. vs. 47±15sec., p = 0.005) compared to HFpEF. Impaired muscle VO2 recovery kinetics following ULKE exercise differentiated HFrEF from HFpEF patients and suggests distinct underlying pathology and potential therapeutic approaches in these populations. PMID:27701422

  15. MRI Predictive Factors for Tumor Response in Rectal Cancer Following Neoadjuvant Chemoradiation Therapy - Implications for Induction Chemotherapy?

    SciTech Connect

    Yu, Stanley K.T.; Tait, Diana

    2013-11-01

    Purpose: Clinical and magnetic resonance imaging (MRI) characteristics at baseline and following chemoradiation therapy (CRT) most strongly associated with histopathologic response were investigated and survival outcomes evaluated in accordance with imaging and pathological response. Methods and Materials: Responders were defined as mrT3c/d-4 downstaged to ypT0-2 on pathology or low at risk mrT2 downstaged to ypT1 or T0. Multivariate logistic regression of baseline and posttreatment MRI: T, N, extramural venous invasion (EMVI), circumferential resection margin, craniocaudal length <5 cm, and MRI tumor height ≤5 cm were used to identify independent predictor(s) for response. An association between induction chemotherapy and EMVI status was analyzed. Survival outcomes for pathologic and MRI responders and nonresponders were analyzed. Results: Two hundred eighty-one patients were eligible; 114 (41%) patients were pathology responders. Baseline MRI negative EMVI (odds ratio 2.94, P=.007), tumor height ≤5 cm (OR 1.96, P=.02), and mrEMVI status change (positive to negative) following CRT (OR 3.09, P<.001) were the only predictors for response. There was a strong association detected between induction chemotherapy and ymrEMVI status change after CRT (OR 9.0, P<.003). ymrT0-2 gave a positive predictive value of 80% and OR of 9.1 for ypT0-2. ymrN stage accuracy of ypN stage was 75%. Three-year disease-free survival for pathology and MRI responders were similar at 80% and 79% and significantly better than poor responders. Conclusions: Tumor height and mrEMVI status are more important than baseline size and stage of the tumor as predictors of response to CRT. Both MRI- and pathologic-defined responders have significantly improved survival. “Good response” to CRT in locally advanced rectal cancer with ypT0-2 carries significantly better 3-year overall survival and disease-free survival. Use of induction chemotherapy for improving mrEMVI status and knowledge of MRI

  16. Thermal sensations and comfort investigations in transient conditions in tropical office.

    PubMed

    Dahlan, Nur Dalilah; Gital, Yakubu Yau

    2016-05-01

    The study was done to identify affective and sensory responses observed as a result of hysteresis effects in transient thermal conditions consisting of warm-neutral and neutral - warm performed in a quasi-experiment setting. Air-conditioned building interiors in hot-humid areas have resulted in thermal discomfort and health risks for people moving into and out of buildings. Reports have shown that the instantaneous change in air temperature can cause abrupt thermoregulation responses. Thermal sensation vote (TSV) and thermal comfort vote (TCV) assessments as a consequence of moving through spaces with distinct thermal conditions were conducted in an existing single-story office in a hot-humid microclimate, maintained at an air temperature 24 °C (± 0.5), relative humidity 51% (± 7), air velocity 0.5 m/s (± 0.5), and mean radiant temperature (MRT) 26.6 °C (± 1.2). The measured office is connected to a veranda that showed the following semi-outdoor temperatures: air temperature 35 °C (± 2.1), relative humidity 43% (± 7), air velocity 0.4 m/s (± 0.4), and MRT 36.4 °C (± 2.9). Subjective assessments from 36 college-aged participants consisting of thermal sensations, preferences and comfort votes were correlated against a steady state predicted mean vote (PMV) model. Local skin temperatures on the forehead and dorsal left hand were included to observe physiological responses due to thermal transition. TSV for veranda-office transition showed that no significant means difference with TSV office-veranda transition were found. However, TCV collected from warm-neutral (-0.24, ± 1.2) and neutral-warm (-0.72, ± 1.3) conditions revealed statistically significant mean differences (p < 0.05). Sensory and affective responses as a consequence of thermal transition after travel from warm-neutral-warm conditions did not replicate the hysteresis effects of brief, slightly cool, thermal sensations found in previous laboratory experiments. These findings also indicate that

  17. MRI Risk Stratification for Tumor Relapse in Rectal Cancer Achieving Pathological Complete Remission after Neoadjuvant Chemoradiation Therapy and Curative Resection

    PubMed Central

    Kim, Honsoul; Myoung, Sungmin; Koom, Woong Sub; Kim, Nam Kyu; Kim, Myeong-Jin; Ahn, Joong Bae; Hur, Hyuk; Lim, Joon Seok

    2016-01-01

    Purpose Rectal cancer patients achieving pCR are known to have an excellent prognosis, yet no widely accepted consensus on risk stratification and post-operative management (e.g., adjuvant therapy) has been established. This study aimed to identify magnetic resonance imaging (MRI) high-risk factors for tumor relapse in pathological complete remission (pCR) achieved by rectal cancer patients who have undergone neoadjuvant concurrent chemoradiation therapy (CRT) and curative resection. Materials and Methods We analyzed 88 (male/female = 55/33, median age, 59.5 years [range 34–78]) pCR-proven rectal cancer patients who had undergone pre-CRT MRI, CRT, post-CRT MRI and curative surgery between July 2005 and December 2012. Patients were observed for post-operative tumor relapse. We analyzed the pre/post-CRT MRIs for parameters including mrT stage, mesorectal fascia (mrMRF) status, tumor volume, tumor regression grade (mrTRG), nodal status (mrN), and extramural vessel invasion (mrEMVI). We performed univariate analysis and Kaplan-Meier survival analysis. Results Post-operative tumor relapse occurred in seven patients (8.0%, n = 7/88) between 5.7 and 50.7 (median 16.8) months. No significant relevance was observed between tumor volume, volume reduction rate, mrTRG, mrT, or mrN status. Meanwhile, positive mrMRF (Ppre-CRT = 0.018, Ppre/post-CRT = 0.006) and mrEMVI (Ppre-CRT = 0.026, Ppre-/post-CRT = 0.008) were associated with higher incidence of post-operative tumor relapse. Kaplan-Meier survival analysis revealed a higher risk of tumor relapse in patients with positive mrMRF (Ppre-CRT = 0.029, Ppre-/post-CRT = 0.009) or mrEMVI (Ppre-CRT = 0.024, Ppre-/post-CRT = 0.003). Conclusion Positive mrMRF and mrEMVI status was associated with a higher risk of post-operative tumor relapse of pCR achieved by rectal cancer patients, and therefore, can be applied for risk stratification and to individualize treatment plans. PMID:26730717

  18. Recent advances in theoretical and numerical studies of wire array Z-pinch in the IAPCM

    NASA Astrophysics Data System (ADS)

    Ding, Ning; Zhang, Yang; Xiao, Delong; Wu, Jiming; Huang, Jun; Yin, Li; Sun, Shunkai; Xue, Chuang; Dai, Zihuan; Ning, Cheng; Shu, Xiaojian; Wang, Jianguo; Li, Hua

    2014-12-01

    Fast Z-pinch has produced the most powerful X-ray radiation source in laboratory and also shows the possibility to drive inertial confinement fusion (ICF). Recent advances in wire-array Z-pinch researches at the Institute of Applied Physics and Computational Mathematics are presented in this paper. A typical wire array Z-pinch process has three phases: wire plasma formation and ablation, implosion and the MRT instability development, stagnation and radiation. A mass injection model with azimuthal modulation coefficient is used to describe the wire initiation, and the dynamics of ablated plasmas of wire-array Z-pinches in (r, θ) geometry is numerically studied. In the implosion phase, a two-dimensional(r, z) three temperature radiation MHD code MARED has been developed to investigate the development of the Magneto-Rayleigh-Taylor(MRT) instability. We also analyze the implosion modes of nested wire-array and find that the inner wire-array is hardly affected before the impaction of the outer wire-array. While the plasma accelerated to high speed in the implosion stage stagnates on the axis, abundant x-ray radiation is produced. The energy spectrum of the radiation and the production mechanism are investigated. The computational x-ray pulse shows a reasonable agreement with the experimental result. We also suggest that using alloyed wire-arrays can increase multi-keV K-shell yield by decreasing the opacity of K-shell lines. In addition, we use a detailed circuit model to study the energy coupling between the generator and the Z-pinch implosion. Recently, we are concentrating on the problems of Z-pinch driven ICF, such as dynamic hohlraum and capsule implosions. Our numerical investigations on the interaction of wire-array Z-pinches on foam convertors show qualitative agreements with experimental results on the "Qiangguang I" facility. An integrated two-dimensional simulation of dynamic hohlraum driven capsule implosion provides us the physical insights of wire

  19. Scaling plant nitrogen use and uptake efficiencies in response to nutrient addition in peatlands.

    PubMed

    Iversen, Colleen M; Bridgham, Scott D; Kellogg, Laurie E

    2010-03-01

    Nitrogen (N) is the primary growth-limiting nutrient in many terrestrial ecosystems, and therefore plant production per unit N taken up (i.e., N use efficiency, NUE) is a fundamentally important component of ecosystem function. Nitrogen use efficiency comprises two components: N productivity (A(N), plant production per peak biomass N content) and the mean residence time of N in plant biomass (MRT(N)). We utilized a five-year fertilization experiment to examine the manner in which increases in N and phosphorus (P) availability affected plant NUE at multiple biological scales (i.e., from leaf to community level). We fertilized a natural gradient of nutrient-limited peatland ecosystems in the Upper Peninsula of Michigan, USA, with 6 g N x m(-2) x yr(-1), 2 g P x m(-2) x yr(-1), or a combination of N and P. Our objectives were to determine how changes in carbon and N allocation within a plant to leaf and woody tissue and changes in species composition within a community, both above- and belowground, would affect (1) NUE; (2) the adaptive trade-off between the components of NUE; (3) the efficiency with which plants acquired N from the soil (N uptake efficiency); and (4) plant community production per unit soil N availability (N response efficiency, NRE). As expected, N and P addition generally increased aboveground production and N uptake. In particular, P availability strongly affected the way in which plants took up and used N. Nitrogen use efficiency response to nutrient addition was not straightforward. Nitrogen use efficiency differed between leaf and woody tissue, among species, and across the ombrotrophic-minerotrophic gradient because plants and communities were adapted to maximize either A(N) or MRT(N), but not both concurrently. Increased N availability strongly decreased plant and community N uptake efficiency, while increased P availability increased N uptake efficiency, particularly in a nitrogen-fixing shrub. Nitrogen uptake efficiency was more important

  20. Transport of soluble carbohydrates in temperate deciduous trees: beech (Fagus sylvatica) and ash (Fraxinus excelsior) in comparison

    NASA Astrophysics Data System (ADS)

    Thoms, Ronny; Köhler, Michael; Gessler, Arthur; Gleixner, Gerd

    2015-04-01

    The structure of phloem cells and the physiology of the transport of soluble carbohydrates in plants are well studied. However, the influence of different phloem un- and uploading strategies on the translocation of carbohydrates in different tree species is largely unknown. Therefore, we conducted a pulse labeling on 20 young trees of European beech (Fagus sylvatica) and European ash (Fraxinus excelsior) respectively, using the stable isotope 13C in a temperate deciduous forest in Central Germany. In one growing season each tree species was labeled in a closed transparent plastic chamber with 99% 13CO2 for 5 h. The compound specific δ 13C from carbohydrates in the different compartments leaf, branch, stem and root was measured by high-performance liquid chromatography linked with an isotope ratio mass spectrometer (HPLC-IRMS). We found that both tree species used sucrose as a transport sugar, but carbohydrates of the raffinose group (RFO) served as main transport sugar in ash trees. This indicate that beech used only the apoplastic loading strategy into the phloem cells while ash trees relied on both, apoplastic and symplastic loading, preferring the latter at the end of the growing season. Furthermore, we observed different transport velocities of labeled sugars in the two species. Here, sucrose in beech and carbohydrates of the RFO in ash were transported fastest, whereas sucrose was constantly slowest in ash trees. The label of carbohydrates was found over 60 day in the roots of both tree species, with the highest δ 13C enrichment in carbohydrates of RFO than in the other sugars. Accordingly, the mean residence time (MRT) and half life time (HLT) of 13C in different compartments were longest for carbohydrates of RFO in roots (25.6 days) and sucrose in stems (14.9 days), while the shortest MRT and HLT for sucrose appeared in beech in all compartments. Our results give evidence that RFO are preferentially transported to the root tissue as an agent against frost