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Sample records for absolute dose difference

  1. A patient-specific quality assurance study on absolute dose verification using ionization chambers of different volumes in RapidArc treatments

    SciTech Connect

    Syam Kumar, S.A.; Sukumar, Prabakar; Sriram, Padmanaban; Rajasekaran, Dhanabalan; Aketi, Srinu; Vivekanandan, Nagarajan

    2012-01-01

    The recalculation of 1 fraction from a patient treatment plan on a phantom and subsequent measurements have become the norms for measurement-based verification, which combines the quality assurance recommendations that deal with the treatment planning system and the beam delivery system. This type of evaluation has prompted attention to measurement equipment and techniques. Ionization chambers are considered the gold standard because of their precision, availability, and relative ease of use. This study evaluates and compares 5 different ionization chambers: phantom combinations for verification in routine patient-specific quality assurance of RapidArc treatments. Fifteen different RapidArc plans conforming to the clinical standards were selected for the study. Verification plans were then created for each treatment plan with different chamber-phantom combinations scanned by computed tomography. This includes Medtec intensity modulated radiation therapy (IMRT) phantom with micro-ionization chamber (0.007 cm{sup 3}) and pinpoint chamber (0.015 cm{sup 3}), PTW-Octavius phantom with semiflex chamber (0.125 cm{sup 3}) and 2D array (0.125 cm{sup 3}), and indigenously made Circular wax phantom with 0.6 cm{sup 3} chamber. The measured isocenter absolute dose was compared with the treatment planning system (TPS) plan. The micro-ionization chamber shows more deviations when compared with semiflex and 0.6 cm{sup 3} with a maximum variation of -4.76%, -1.49%, and 2.23% for micro-ionization, semiflex, and farmer chambers, respectively. The positive variations indicate that the chamber with larger volume overestimates. Farmer chamber shows higher deviation when compared with 0.125 cm{sup 3}. In general the deviation was found to be <1% with the semiflex and farmer chambers. A maximum variation of 2% was observed for the 0.007 cm{sup 3} ionization chamber, except in a few cases. Pinpoint chamber underestimates the calculated isocenter dose by a maximum of 4.8%. Absolute dose

  2. Comprehensive fluence model for absolute portal dose image prediction

    SciTech Connect

    Chytyk, K.; McCurdy, B. M. C.

    2009-04-15

    Amorphous silicon (a-Si) electronic portal imaging devices (EPIDs) continue to be investigated as treatment verification tools, with a particular focus on intensity modulated radiation therapy (IMRT). This verification could be accomplished through a comparison of measured portal images to predicted portal dose images. A general fluence determination tailored to portal dose image prediction would be a great asset in order to model the complex modulation of IMRT. A proposed physics-based parameter fluence model was commissioned by matching predicted EPID images to corresponding measured EPID images of multileaf collimator (MLC) defined fields. The two-source fluence model was composed of a focal Gaussian and an extrafocal Gaussian-like source. Specific aspects of the MLC and secondary collimators were also modeled (e.g., jaw and MLC transmission factors, MLC rounded leaf tips, tongue and groove effect, interleaf leakage, and leaf offsets). Several unique aspects of the model were developed based on the results of detailed Monte Carlo simulations of the linear accelerator including (1) use of a non-Gaussian extrafocal fluence source function, (2) separate energy spectra used for focal and extrafocal fluence, and (3) different off-axis energy spectra softening used for focal and extrafocal fluences. The predicted energy fluence was then convolved with Monte Carlo generated, EPID-specific dose kernels to convert incident fluence to dose delivered to the EPID. Measured EPID data were obtained with an a-Si EPID for various MLC-defined fields (from 1x1 to 20x20 cm{sup 2}) over a range of source-to-detector distances. These measured profiles were used to determine the fluence model parameters in a process analogous to the commissioning of a treatment planning system. The resulting model was tested on 20 clinical IMRT plans, including ten prostate and ten oropharyngeal cases. The model predicted the open-field profiles within 2%, 2 mm, while a mean of 96.6% of pixels over

  3. An absolute dose determination of helical tomotherapy accelerator, TomoTherapy High-Art II

    SciTech Connect

    Bailat, Claude J.; Buchillier, Thierry; Pachoud, Marc; Moeckli, Raphaeel; Bochud, Francois O.

    2009-09-15

    Purpose: A helical tomotherapy accelerator presents a dosimetric challenge because, to this day, there is no internationally accepted protocol for the determination of the absolute dose. Because of this reality, we investigated the different alternatives for characterizing and measuring the absolute dose of such an accelerator. We tested several dosimetric techniques with various metrological traceabilities as well as using a number of phantoms in static and helical modes. Methods: Firstly, the relationship between the reading of ionization chambers and the absorbed dose is dependent on the beam quality value of the photon beam. For high energy photons, the beam quality is specified by the tissue phantom ratio (TPR{sub 20,10}) and it is therefore necessary to know the TPR{sub 20,10} to calculate the dose delivered by a given accelerator. This parameter is obtained through the ratio of the absorbed dose at 20 and 10 cm depths in water and was measured in the particular conditions of the tomotherapy accelerator. Afterward, measurements were performed using the ionization chamber (model A1SL) delivered as a reference instrument by the vendor. This chamber is traceable in absorbed dose to water in a Co-60 beam to a water calorimeter of the American metrology institute (NIST). Similarly, in Switzerland, each radiotherapy department is directly traceable to the Swiss metrology institute (METAS) in absorbed dose to water based on a water calorimeter. For our research, this traceability was obtained by using an ionization chamber traceable to METAS (model NE 2611A), which is the secondary standard of our institute. Furthermore, in order to have another fully independent measurement method, we determined the dose using alanine dosimeters provided by and traceable to the British metrology institute (NPL); they are calibrated in absorbed dose to water using a graphite calorimeter. And finally, we wanted to take into account the type of chamber routinely used in clinical

  4. The impact of water temperature on the measurement of absolute dose

    NASA Astrophysics Data System (ADS)

    Islam, Naveed Mehdi

    To standardize reference dosimetry in radiation therapy, Task Group 51 (TG 51) of American Association of Physicist's in Medicine (AAPM) recommends that dose calibration measurements be made in a water tank at a depth of 10 cm and at a reference geometry. Methodologies are provided for calculating various correction factors to be applied in calculating the absolute dose. However the protocol does not specify the water temperature to be used. In practice, the temperature of water during dosimetry may vary considerably between independent sessions and different centers. In this work the effect of water temperature on absolute dosimetry has been investigated. Density of water varies with temperature, which in turn may impact the beam attenuation and scatter properties. Furthermore, due to thermal expansion or contraction air volume inside the chamber may change. All of these effects can result in a change in the measurement. Dosimetric measurements were made using a Farmer type ion chamber on a Varian Linear Accelerator for 6 MV and 23 MV photon energies for temperatures ranging from 10 to 40 °C. A thermal insulation was designed for the water tank in order to maintain relatively stable temperature over the duration of the experiment. Dose measured at higher temperatures were found to be consistently higher by a very small magnitude. Although the differences in dose were less than the uncertainty in each measurement, a linear regression of the data suggests that the trend is statistically significant with p-values of 0.002 and 0.013 for 6 and 23 MV beams respectively. For a 10 degree difference in water phantom temperatures, which is a realistic deviation across clinics, the final calculated reference dose can differ by 0.24% or more. To address this effect, first a reference temperature (e.g.22 °C) can be set as the standard; subsequently a correction factor can be implemented for deviations from this reference. Such a correction factor is expected to be of similar

  5. Use of intensity quotients and differences in absolute structure refinement.

    PubMed

    Parsons, Simon; Flack, Howard D; Wagner, Trixie

    2013-06-01

    Several methods for absolute structure refinement were tested using single-crystal X-ray diffraction data collected using Cu Kα radiation for 23 crystals with no element heavier than oxygen: conventional refinement using an inversion twin model, estimation using intensity quotients in SHELXL2012, estimation using Bayesian methods in PLATON, estimation using restraints consisting of numerical intensity differences in CRYSTALS and estimation using differences and quotients in TOPAS-Academic where both quantities were coded in terms of other structural parameters and implemented as restraints. The conventional refinement approach yielded accurate values of the Flack parameter, but with standard uncertainties ranging from 0.15 to 0.77. The other methods also yielded accurate values of the Flack parameter, but with much higher precision. Absolute structure was established in all cases, even for a hydrocarbon. The procedures in which restraints are coded explicitly in terms of other structural parameters enable the Flack parameter to correlate with these other parameters, so that it is determined along with those parameters during refinement. PMID:23719469

  6. Using a dose-area product for absolute measurements in small fields: a feasibility study.

    PubMed

    Dufreneix, S; Ostrowsky, A; Le Roy, M; Sommier, L; Gouriou, J; Delaunay, F; Rapp, B; Daures, J; Bordy, J-M

    2016-01-21

    To extend the dosimetric reference system to field sizes smaller than 2 cm × 2 cm, the LNE-LNHB laboratory is studying an approach based on a new dosimetric quantity named the dose-area product instead of the commonly used absorbed dose at a point. A graphite calorimeter and a plane parallel ion chamber with a sensitive surface of 3 cm diameter were designed and built for measurements in fields of 2, 1 and 0.75 cm diameter. The detector surface being larger than the beam section, most of the issues linked with absolute dose measurements at a point could be avoided. Calibration factors of the plane parallel ionization chamber were established in terms of dose-area product in water for small fields with an uncertainty smaller than 0.9%. PMID:26690271

  7. Evaluation of clinical IMRT treatment planning using the GATE Monte Carlo simulation platform for absolute and relative dose calculations

    SciTech Connect

    Benhalouche, S.; Le Maitre, A.; Visvikis, D.; Pradier, O.; Boussion, N.

    2013-02-15

    Purpose: The objective of this study was to evaluate and validate the use of the Geant4 application for emission tomography (GATE) Monte Carlo simulation platform for clinical intensity modulated radiotherapy (IMRT) dosimetry studies. Methods: The first step consisted of modeling a 6 MV photon beam linear accelerator (LINAC), with its corresponding validation carried out using percent depth dose evaluation, transverse profiles, tissue phantom ratio, and output factor on water phantom. The IMRT evaluation was performed by comparing simulation and measurements in terms of absolute and relative doses using IMRT dedicated quality assurance phantoms considering seven different patient datasets. Results: Concerning the LINAC simulated model validation tissue phantom ratios at 20 and 10 cm in water TPR{sub 10}{sup 20} obtained from GATE and measurements were 0.672 {+-} 0.063 and 0.675, respectively. In terms of percent depth dose and transverse profiles, error ranges were, respectively: 1.472%{+-} 0.285% and 4.827%{+-} 1.323% for field size of 4 Multiplication-Sign 4, 5 Multiplication-Sign 5, 10 Multiplication-Sign 10, 15 Multiplication-Sign 15, 20 Multiplication-Sign 20, 25 Multiplication-Sign 25, 30 Multiplication-Sign 30, and 40 Multiplication-Sign 40 cm{sup 2}. Most errors were observed at the edge of radiation fields because of higher dose gradient in these areas. Output factors showed good agreement between simulation and measurements with a maximum error of 1.22%. Finally, for IMRT simulations considering seven patient datasets, GATE provided good results with a relative error of 0.43%{+-} 0.25% on absolute dose between simulated and measured beams (measurements at the isocenter, volume 0.125 cm{sup 3}). Planar dose comparisons were also performed using gamma-index analysis. For the whole set of beams considered the mean gamma-index value was 0.497 {+-} 0.152 and 90.8%{+-} 3.6% of the evaluated dose points satisfied the 5%/ 4 mm criterion. Conclusions: These

  8. Single- and Multiple-Dose Pharmacokinetics and Absolute Bioavailability of Tedizolid

    PubMed Central

    Flanagan, Shawn; Fang, Edward; Muñoz, Kelly A; Minassian, Sonia L; Prokocimer, Philippe G

    2014-01-01

    Objectives Tedizolid phosphate is a novel antibacterial under investigation for the treatment of gram-positive infections. This study was conducted to assess the pharmacokinetics, safety, and tolerability of intravenous tedizolid phosphate as well as the oral bioavailability of tedizolid phosphate. Design Double-blind, single-ascending dose, multiple-dose pharmacokinetics study, as well as tolerability and open-label crossover studies. Setting Single center in the United States (Covance Clinical Research Unit, Madison, WI) between September 2009 and January 2010. Participants Ninety healthy volunteers. Intervention Single intravenous (IV) doses of tedizolid phosphate 50 mg (lead-in) and 100–400 mg. Single oral and IV dose of tedizolid phosphate 200 mg in crossover fashion. Multiple IV doses of tedizolid phosphate 200 and 300 mg for up to 7 days. Measurements and Main Results A dose-dependent increase was observed in the maximum plasma concentration (1.2–5.1 μg/ml) and the area under the concentration-time curve (17.4–58.7 μg × hr/ml) of tedizolid (the microbiologically active moiety of tedizolid phosphate) after single IV doses of tedizolid phosphate 100–400 mg. Administration of IV tedizolid phosphate 200 mg once/day for 7 days resulted in minimal (28%) tedizolid accumulation. The absolute oral bioavailability of tedizolid after a single 200-mg dose of tedizolid phosphate was 91%; pharmacokinetic parameters of tedizolid were similar with oral and IV administration. Treatment-related adverse events occurred in 41% of subjects. Most adverse events were related to infusion site and became more frequent with multiple dosing. In an additional 3-day tolerability study, IV tedizolid phosphate 200 mg and placebo were similarly tolerated, based on visual infusion phlebitis scores. Conclusion These results from a population of healthy volunteers support once/day dosing of tedizolid phosphate 200 mg with both the oral and IV formulations, without the

  9. Absolute depth-dose-rate measurements for an {sup 192}Ir HDR brachytherapy source in water using MOSFET detectors

    SciTech Connect

    Zilio, Valery Olivier; Joneja, Om Parkash; Popowski, Youri; Rosenfeld, Anatoly; Chawla, Rakesh

    2006-06-15

    Reported MOSFET measurements concern mostly external radiotherapy and in vivo dosimetry. In this paper, we apply the technique for absolute dosimetry in the context of HDR brachytherapy using an {sup 192}Ir source. Measured radial dose rate distributions in water for different planes perpendicular to the source axis are presented and special attention is paid to the calibration of the R and K type detectors, and to the determination of appropriate correction factors for the sensitivity variation with the increase of the threshold voltage and the energy dependence. The experimental results are compared with Monte Carlo simulated dose rate distributions. The experimental results show a good agreement with the Monte Carlo simulations: the discrepancy between experimental and Monte Carlo results being within 5% for 82% of the points and within 10% for 95% of the points. Moreover, all points except two are found to lie within the experimental uncertainties, confirming thereby the quality of the results obtained.

  10. Individual Differences in Absolute and Relative Metacomprehension Accuracy

    ERIC Educational Resources Information Center

    Maki, Ruth H.; Shields, Micheal; Wheeler, Amanda Easton; Zacchilli, Tammy Lowery

    2005-01-01

    The authors investigated absolute and relative metacomprehension accuracy as a function of verbal ability in college students. Students read hard texts, revised texts, or a mixed set of texts. They then predicted their performance, took a multiple-choice test on the texts, and made posttest judgments about their performance. With hard texts,…

  11. Effect of various methods for rectum delineation on relative and absolute dose-volume histograms for prostate IMRT treatment planning.

    PubMed

    Kusumoto, Chiaki; Ohira, Shingo; Miyazaki, Masayoshi; Ueda, Yoshihiro; Isono, Masaru; Teshima, Teruki

    2016-01-01

    Several reports have dealt with correlations of late rectal toxicity with rectal dose-volume histograms (DVHs) for high dose levels. There are 2 techniques to assess rectal volume for reception of a specific dose: relative-DVH (R-DVH, %) that indicates relative volume for a vertical axis, and absolute-DVH (A-DVH, cc) with its vertical axis showing absolute volume of the rectum. The parameters of DVH vary depending on the rectum delineation method, but the literature does not present any standardization of such methods. The aim of the present study was to evaluate the effects of different delineation methods on rectal DVHs. The enrollment for this study comprised 28 patients with high-risk localized prostate cancer, who had undergone intensity-modulated radiation therapy (IMRT) with the prescription dose of 78Gy. The rectum was contoured with 4 different methods using 2 lengths, short (Sh) and long (Lg), and 2 cross sections, rectum (Rec) and rectal wall (Rw). Sh means the length from 1cm above the seminal vesicles to 1cm below the prostate and Lg the length from the rectosigmoid junction to the anus. Rec represents the entire rectal volume including the rectal contents and Rw the rectal volume of the area with a wall thickness of 4mm. We compared dose-volume parameters by using 4 rectal contour methods for the same plan with the R-DVHs as well as the A-DVHs. For the high dose levels, the R-DVH parameters varied widely. The mean of V70 for Sh-Rw was the highest (19.4%) and nearly twice as high as that for Lg-Rec (10.4%). On the contrary, only small variations were observed in the A-DVH parameters (4.3, 4.3, 5.5, and 5.5cc for Sh-Rw, Lg-Rw, Sh-Rec, and Lg-Rec, respectively). As for R-DVHs, the parameters of V70 varied depending on the rectal lengths (Sh-Rec vs Lg-Rec: R = 0.76; Sh-Rw vs Lg-Rw: R = 0.85) and cross sections (Sh-Rec vs Sh-Rw: R = 0.49; Lg-Rec vs Lg-Rw: R = 0.65). For A-DVHs, however, the parameters of Sh rectal A-DVHs hardly changed regardless of

  12. TU-A-12A-09: Absolute Blood Flow Measurement in a Cardiac Phantom Using Low Dose CT

    SciTech Connect

    Ziemer, B; Hubbard, L; Lipinski, J; Molloi, S

    2014-06-15

    Purpose: To investigate a first pass analysis technique to measure absolute flow from low dose CT images in a cardiac phantom. This technique can be combined with a myocardial mass assignment to yield absolute perfusion using only two volume scans and reduce the radiation dose to the patient. Methods: A four-chamber cardiac phantom and perfusion chamber were constructed from poly-acrylic and connected with tubing to approximate anatomical features. The system was connected to a pulsatile pump, input/output reservoirs and power contrast injector. Flow was varied in the range of 1-2.67 mL/s with the pump operating at 60 beats/min. The system was imaged once a second for 14 seconds with a 320-row scanner (Toshiba Medical Systems) using a contrast-enhanced, prospective-gated cardiac perfusion protocol. Flow was calculated by the following steps: subsequent images of the perfusion volume were subtracted to find the contrast entering the volume; this was normalized by an upstream, known volume region to convert Hounsfield (HU) values to concentration; this was divided by the subtracted images time difference. The technique requires a relatively stable input contrast concentration and no contrast can leave the perfusion volume before the flow measurement is completed. Results: The flow calculated from the images showed an excellent correlation with the known rates. The data was fit to a linear function with slope 1.03, intercept 0.02 and an R{sup 2} value of 0.99. The average root mean square (RMS) error was 0.15 mL/s and the average standard deviation was 0.14 mL/s. The flow rate was stable within 7.7% across the full scan and served to validate model assumptions. Conclusion: Accurate, absolute flow rates were measured from CT images using a conservation of mass model. Measurements can be made using two volume scans which can substantially reduce the radiation dose compared with current dynamic perfusion techniques.

  13. Commissioning and Implementation of an EPID Based IMRT QA System "Dosimetry Check" for 3D Absolute Dose Measurements and Quantitative Comparisons to MapCheck

    NASA Astrophysics Data System (ADS)

    Patel, Jalpa A.

    The software package "Dosimetry Check" by MathResolutions, LLC, provides an absolute 3D volumetric dose measurement for IMRT QA using the existing Electronic Portal Imaging Device (EPID) mounted on most linear accelerators. This package provides a feedback loop using the patient's treatment planning CT data as the phantom for dose reconstruction. The aim of this work is to study the difference between point, planar and volumetric doses with MapCheck and Dosimetry Check via the use of the EPID and the diode array respectively. Evaluating tools such as point doses at isocenter, 1-D profiles, gamma volume histograms, and dose volume histograms are used for IMRT dose comparison in three types of cases: head and neck, prostate, and lung. Dosimetry Check can be a valuable tool for IMRT QA as it uses patient specific attenuation corrections and the superiority of the EPID as compared to the MapCheck diode array. This helps reduce the uncertainty in dose for less variability in delivery and a more realistic measured vs computed dose verification system as compared to MapCheck.

  14. Easy Absolute Values? Absolutely

    ERIC Educational Resources Information Center

    Taylor, Sharon E.; Mittag, Kathleen Cage

    2015-01-01

    The authors teach a problem-solving course for preservice middle-grades education majors that includes concepts dealing with absolute-value computations, equations, and inequalities. Many of these students like mathematics and plan to teach it, so they are adept at symbolic manipulations. Getting them to think differently about a concept that they…

  15. Sci—Fri PM: Dosimetry — 03: Delta4 diode absolute dose response for large and small target volume IMRT QA

    SciTech Connect

    Simard, D; Thakur, V

    2014-08-15

    The goal of this project was to quantify the over-response/under-response of the Delta4 diodes for Helical Tomotherapy plans on extreme target volume sizes. A custom Delta4 phantom quarter with a hole to insert an ionisation chamber (IC) close to the center of the phantom have been used to acquire simultaneous IC and diodes absolute dose measurements. Eight plans for different target volumes were created from 20cm to 1cm diameter. Diodes dose measurements in the target were compared with IC measurement, to quantify absolute dose accuracy. IC measurements show a good agreement with planned dose (±2%). Diode measurements demonstrate a good agreement with IC for regular target size of 5 and 10cm (0 to 1%). For larger targets, an over-response is observed for FW 25mm and 10mm (2 to 3%). for small target of 1cm diameter, a major under-response is observed for FW 25mm and 10mm (−8 and −36%). The over-response could to be due to the extra amount of scattered radiation and the opposite for under-response. Although this scatter hypothesis still has to be proven, early testing demonstrates an over-response of 40%/20% of the central diodes compare to IC when an open helical rotational beam is delivered 75mm/25mm away from the center of the phantom. These results are in agreement with the real patient Delta4 DQA results at our center.

  16. Mass versus molar doses, similarities and differences.

    PubMed

    Chmielewska, A; Lamparczyk, H

    2008-11-01

    Generally, they are two systems expressing the amounts of active substance in a given drug product, i.e. mass and molar dose. Currently, the dose system based on the mass is widely used in which doses are expressed in grams or milligrams. On the other hand, the molar dose system is in direct relation to the number of molecules. Hence, the objective of this work was to compare both systems in order to find their advantages and disadvantages. Active substances belonging to the groups of antibiotics, nootropic agents, beta-blockers, vitamins, GABA-analog, COX-2 inhibitors, calcium channel antagonists, benzodiazepine receptor agonists, lipid-modifying agents (fibrates), non-steroidal anti-inflammatory drugs (profens), estrogens, neuroleptics, analgesics and benzodiazepines were considered. Moreover, products containing two active substances were also taken into account. These are mixtures of hydrochlorothiazide with active substances influencing the renin-angiotensin system and combined oral contraceptives. For each active substance, belonging to the groups mentioned above molar doses were calculated from mass doses and molar mass. Hence, groups of drugs with a single active substance, drugs with similar pharmacological activities, pharmaceutical alternatives, and drugs with a single active ingredient manufactured in different doses were compared in order to find which dose system describes more adequately differences between and within the groups mentioned above. Comparisons were supported by a number of equations, which theoretically justify the data, and relationships derived from calculations. PMID:19069248

  17. Absolute dose measurements by means of a small cylindrical ionization chamber for very high dose per pulse high energy electron beams

    SciTech Connect

    Karaj, E.; Righi, S.; Di Martino, F.

    2007-03-15

    Very high dose per pulse (3-13 cGy/pulse) high energy electron beams are currently produced by special linear accelerators (linac) dedicated to Intra Operative Radiation Therapy (IORT). The electron beams produced by such linacs are collimated by special Perspex applicators of various size and cylindrically shaped. The biggest problems from the dosimetric point of view are caused by the high dose-per-pulse values and the use of inclined applicators. In this work measurements of absolute dose for the inclined applicators were done by using a small cylindrical ionization chamber, type CC01 (Wellhofer), a parallel plane ionization chamber type Markus (PTW 23343) and radiochromic films type EBT. We show a method which allows calculating the quality correction factors for CC01 chamber with an uncertainty of 1% and the absolute dose value for the inclined applicators using CC01 with an uncertainty of 3.1% for electron beams of energy of 6 and 7 MeV produced by the linac dedicated to IORT Novac7.

  18. Relative and Absolute Error Control in a Finite-Difference Method Solution of Poisson's Equation

    ERIC Educational Resources Information Center

    Prentice, J. S. C.

    2012-01-01

    An algorithm for error control (absolute and relative) in the five-point finite-difference method applied to Poisson's equation is described. The algorithm is based on discretization of the domain of the problem by means of three rectilinear grids, each of different resolution. We discuss some hardware limitations associated with the algorithm,…

  19. Absolute calibration of the Gamma Knife{sup ®} Perfexion™ and delivered dose verification using EPR/alanine dosimetry

    SciTech Connect

    Hornbeck, Amaury E-mail: tristan.garcia@cea.fr; Garcia, Tristan E-mail: tristan.garcia@cea.fr; Cuttat, Marguerite; Jenny, Catherine

    2014-06-15

    Purpose: Elekta Leksell Gamma Knife{sup ®} (LGK) is a radiotherapy beam machine whose features are not compliant with the international calibration protocols for radiotherapy. In this scope, the Laboratoire National Henri Becquerel and the Pitié-Salpêtrière Hospital decided to conceive a new LKG dose calibration method and to compare it with the currently used one. Furthermore, the accuracy of the dose delivered by the LGK machine was checked using an “end-to-end” test. This study also aims to compare doses delivered by the two latest software versions of the Gammaplan treatment planning system (TPS). Methods: The dosimetric method chosen is the electron paramagnetic resonance (EPR) of alanine. Dose rate (calibration) verification was done without TPS using a spherical phantom. Absolute calibration was done with factors calculated by Monte Carlo simulation (MCNP-X). For “end-to-end” test, irradiations in an anthropomorphic head phantom, close to real treatment conditions, are done using the TPS in order to verify the delivered dose. Results: The comparison of the currently used calibration method with the new one revealed a deviation of +0.8% between the dose rates measured by ion chamber and EPR/alanine. For simple fields configuration (less than 16 mm diameter), the “end-to-end” tests showed out average deviations of −1.7% and −0.9% between the measured dose and the calculated dose by Gammaplan v9 and v10, respectively. Conclusions: This paper shows there is a good agreement between the new calibration method and the currently used one. There is also a good agreement between the calculated and delivered doses especially for Gammaplan v10.

  20. SU-E-J-85: Leave-One-Out Perturbation (LOOP) Fitting Algorithm for Absolute Dose Film Calibration

    SciTech Connect

    Chu, A; Ahmad, M; Chen, Z; Nath, R

    2014-06-01

    Purpose: To introduce an outliers-recognition fitting routine for film dosimetry. It cannot only be flexible with any linear and non-linear regression but also can provide information for the minimal number of sampling points, critical sampling distributions and evaluating analytical functions for absolute film-dose calibration. Methods: The technique, leave-one-out (LOO) cross validation, is often used for statistical analyses on model performance. We used LOO analyses with perturbed bootstrap fitting called leave-one-out perturbation (LOOP) for film-dose calibration . Given a threshold, the LOO process detects unfit points (“outliers”) compared to other cohorts, and a bootstrap fitting process follows to seek any possibilities of using perturbations for further improvement. After that outliers were reconfirmed by a traditional t-test statistics and eliminated, then another LOOP feedback resulted in the final. An over-sampled film-dose- calibration dataset was collected as a reference (dose range: 0-800cGy), and various simulated conditions for outliers and sampling distributions were derived from the reference. Comparisons over the various conditions were made, and the performance of fitting functions, polynomial and rational functions, were evaluated. Results: (1) LOOP can prove its sensitive outlier-recognition by its statistical correlation to an exceptional better goodness-of-fit as outliers being left-out. (2) With sufficient statistical information, the LOOP can correct outliers under some low-sampling conditions that other “robust fits”, e.g. Least Absolute Residuals, cannot. (3) Complete cross-validated analyses of LOOP indicate that the function of rational type demonstrates a much superior performance compared to the polynomial. Even with 5 data points including one outlier, using LOOP with rational function can restore more than a 95% value back to its reference values, while the polynomial fitting completely failed under the same conditions

  1. The Impact of Different Absolute Solar Irradiance Values on Current Climate Model Simulations

    NASA Technical Reports Server (NTRS)

    Rind, David H.; Lean, Judith L.; Jonas, Jeffrey

    2014-01-01

    Simulations of the preindustrial and doubled CO2 climates are made with the GISS Global Climate Middle Atmosphere Model 3 using two different estimates of the absolute solar irradiance value: a higher value measured by solar radiometers in the 1990s and a lower value measured recently by the Solar Radiation and Climate Experiment. Each of the model simulations is adjusted to achieve global energy balance; without this adjustment the difference in irradiance produces a global temperature change of 0.48C, comparable to the cooling estimated for the Maunder Minimum. The results indicate that by altering cloud cover the model properly compensates for the different absolute solar irradiance values on a global level when simulating both preindustrial and doubled CO2 climates. On a regional level, the preindustrial climate simulations and the patterns of change with doubled CO2 concentrations are again remarkably similar, but there are some differences. Using a higher absolute solar irradiance value and the requisite cloud cover affects the model's depictions of high-latitude surface air temperature, sea level pressure, and stratospheric ozone, as well as tropical precipitation. In the climate change experiments it leads to an underestimation of North Atlantic warming, reduced precipitation in the tropical western Pacific, and smaller total ozone growth at high northern latitudes. Although significant, these differences are typically modest compared with the magnitude of the regional changes expected for doubled greenhouse gas concentrations. Nevertheless, the model simulations demonstrate that achieving the highest possible fidelity when simulating regional climate change requires that climate models use as input the most accurate (lower) solar irradiance value.

  2. OCT angiography by absolute intensity difference applied to normal and diseased human retinas

    PubMed Central

    Ruminski, Daniel; Sikorski, Bartosz L.; Bukowska, Danuta; Szkulmowski, Maciej; Krawiec, Krzysztof; Malukiewicz, Grazyna; Bieganowski, Lech; Wojtkowski, Maciej

    2015-01-01

    We compare four optical coherence tomography techniques for noninvasive visualization of microcapillary network in the human retina and murine cortex. We perform phantom studies to investigate contrast-to-noise ratio for angiographic images obtained with each of the algorithm. We show that the computationally simplest absolute intensity difference angiographic OCT algorithm that bases only on two cross-sectional intensity images may be successfully used in clinical study of healthy eyes and eyes with diabetic maculopathy and branch retinal vein occlusion. PMID:26309740

  3. SU-E-T-189: First Experimental Verification of the Accuracy of Absolute Dose Reconstruction From PET-CT Imaging of Yttrium 90 Microspheres

    SciTech Connect

    Veltchev, I; Fourkal, E; Doss, M; Ma, C; Meyer, J; Yu, M; Horwitz, E

    2014-06-01

    Purpose: In the past few years there have been numerous proposals for 3D dose reconstruction from the PET-CT imaging of patients undergoing radioembolization treatment of the liver with yttrium-90 microspheres. One of the most promising techniques uses convolution of the measured PET activity distribution with a pre-calculated Monte Carlo dose deposition kernel. The goal of the present study is to experimentally verify the accuracy of this method and to analyze the significance of various error sources. Methods: Optically stimulated luminescence detectors (OSLD) were used (NanoDot, Landauer) in this experiment. Two detectors were mounted on the central axis of a cylinder filled with water solution of yttrium-90 chloride. The total initial activity was 90mCi. The cylinder was inserted in a larger water phantom and scanned on a Siemens Biograph 16 Truepoint PET-CT scanner. Scans were performed daily over a period of 20 days to build a calibration curve for the measured absolute activity spanning 7 yttrium-90 half-lives. The OSLDs were mounted in the phantom for a predetermined period of time in order to record 2Gy dose. The measured dose was then compared to the dose reconstructed from the activity density at the location of each dosimeter. Results: Thorough error analysis of the dose reconstruction algorithm takes into account the uncertainties in the absolute PET activity, branching ratios, and nonlinearity of the calibration curve. The measured dose for 105-minute exposure on day 10 of the experiment was 219(11)cGy, while the reconstructed dose at the location of the detector was 215(47)cGy. Conclusion: We present the first experimental verification of the accuracy of the convolution algorithm for absolute dose reconstruction of yttrium-90 microspheres. The excellent agreement between the measured and calculated point doses will encourage the broad clinical adoption of the convolution-based dose reconstruction algorithm, making future quantitative dose

  4. An evaluation method based on absolute difference to validate the performance of SBNUC algorithms

    NASA Astrophysics Data System (ADS)

    Jin, Minglei; Jin, Weiqi; Li, Yiyang; Li, Shuo

    2016-09-01

    Scene-based non-uniformity correction (SBNUC) algorithms are an important part of infrared image processing; however, SBNUC algorithms usually cause two defects: (1) ghosting artifacts and (2) over-correction. In this paper, we use the absolute difference based on guided image filter (AD-GF) method to validate the performance of SBNUC algorithms. We obtain a self-separation source using the improved guided image filter to process the input image, and use the self-separation source to obtain the space-high-frequency parts of the input image and the corrected image. Finally, we use the absolute difference between the two space-high-frequency parts as the evaluation result. Based on experimental results, the AD-GF method has better robustness and can validate the performance of SBNUC algorithms even if ghosting artifacts or over-correction occur. Also the AD-GF method can measure how SBNUC algorithms perform in the time domain, it's an effective evaluation method for SBNUC algorithm.

  5. Comparison of different standards for real-time PCR-based absolute quantification.

    PubMed

    Dhanasekaran, S; Doherty, T Mark; Kenneth, John

    2010-03-31

    Quantitative real-time PCR (qPCR) is a powerful tool used for both research and diagnostic, which has the advantage, compared to relative quantification, of providing an absolute copy number for a particular target. However, reliable standards are essential for qPCR. In this study, we have compared four types of commonly-used standards--PCR products (with and without purification) and cloned target sequences (circular and linear plasmid) for their stability during storage (using percentage of variance in copy numbers, PCR efficiency and regression curve correlation coefficient (R(2))) using hydrolysis probe (TaqMan) chemistry. Results, expressed as copy numbers/microl, are presented from a sample human system in which absolute levels of HuPO (reference gene) and the cytokine gene IFN-gamma were measured. To ensure the suitability and stability of the four standards, the experiments were performed at 0, 7 and 14 day intervals and repeated 6 times. We have found that the copy numbers vary (due to degradation of standards) over the period of time during storage at 4 degrees C and -20 degrees C, which affected PCR efficiency significantly. The cloned target sequences were noticeably more stable than the PCR product, which could lead to substantial variance in results using standards constructed by different routes. Standard quality and stability should be routinely tested for assays using qPCR.

  6. Radioactivity measurements of 177Lu, 111In and 123I by different absolute methods.

    PubMed

    Rezende, E A; Correia, A R; Iwahara, A; da Silva, C J; Tauhata, L; Poledna, R; da Silva, R L; de Oliveira, E M; de Oliveira, A E

    2012-09-01

    The activities of (177)Lu, (111)In and (123)I solutions have been absolutely determined using three different measurement methods. (177)Lu solution was standardized using the 4πβ(PC)-γ(NaI) coincidence and 4πβ(LS)-γ(NaI) live-timed anticoincidence methods. For the (111)In and (123)I solutions, besides these two mentioned methods, the coincidence sum-peak method was also applied. The measured activities results using these different methods are consistent within the evaluated experimental uncertainties demonstrating the equivalence of these methods. As an additional contribution to nuclear data, the half-lives have been determined using a well type IG12 ionization chamber.

  7. Radioactivity measurements of 177Lu, 111In and 123I by different absolute methods.

    PubMed

    Rezende, E A; Correia, A R; Iwahara, A; da Silva, C J; Tauhata, L; Poledna, R; da Silva, R L; de Oliveira, E M; de Oliveira, A E

    2012-09-01

    The activities of (177)Lu, (111)In and (123)I solutions have been absolutely determined using three different measurement methods. (177)Lu solution was standardized using the 4πβ(PC)-γ(NaI) coincidence and 4πβ(LS)-γ(NaI) live-timed anticoincidence methods. For the (111)In and (123)I solutions, besides these two mentioned methods, the coincidence sum-peak method was also applied. The measured activities results using these different methods are consistent within the evaluated experimental uncertainties demonstrating the equivalence of these methods. As an additional contribution to nuclear data, the half-lives have been determined using a well type IG12 ionization chamber. PMID:22401938

  8. Modeling absolute differences in life expectancy with a censored skew-normal regression approach

    PubMed Central

    Clough-Gorr, Kerri; Zwahlen, Marcel

    2015-01-01

    Parameter estimates from commonly used multivariable parametric survival regression models do not directly quantify differences in years of life expectancy. Gaussian linear regression models give results in terms of absolute mean differences, but are not appropriate in modeling life expectancy, because in many situations time to death has a negative skewed distribution. A regression approach using a skew-normal distribution would be an alternative to parametric survival models in the modeling of life expectancy, because parameter estimates can be interpreted in terms of survival time differences while allowing for skewness of the distribution. In this paper we show how to use the skew-normal regression so that censored and left-truncated observations are accounted for. With this we model differences in life expectancy using data from the Swiss National Cohort Study and from official life expectancy estimates and compare the results with those derived from commonly used survival regression models. We conclude that a censored skew-normal survival regression approach for left-truncated observations can be used to model differences in life expectancy across covariates of interest. PMID:26339544

  9. TH-E-BRE-09: TrueBeam Monte Carlo Absolute Dose Calculations Using Monitor Chamber Backscatter Simulations and Linac-Logged Target Current

    SciTech Connect

    A, Popescu I; Lobo, J; Sawkey, D; Svatos, M

    2014-06-15

    Purpose: To simulate and measure radiation backscattered into the monitor chamber of a TrueBeam linac; establish a rigorous framework for absolute dose calculations for TrueBeam Monte Carlo (MC) simulations through a novel approach, taking into account the backscattered radiation and the actual machine output during beam delivery; improve agreement between measured and simulated relative output factors. Methods: The ‘monitor backscatter factor’ is an essential ingredient of a well-established MC absolute dose formalism (the MC equivalent of the TG-51 protocol). This quantity was determined for the 6 MV, 6X FFF, and 10X FFF beams by two independent Methods: (1) MC simulations in the monitor chamber of the TrueBeam linac; (2) linac-generated beam record data for target current, logged for each beam delivery. Upper head MC simulations used a freelyavailable manufacturer-provided interface to a cloud-based platform, allowing use of the same head model as that used to generate the publicly-available TrueBeam phase spaces, without revealing the upper head design. The MC absolute dose formalism was expanded to allow direct use of target current data. Results: The relation between backscatter, number of electrons incident on the target for one monitor unit, and MC absolute dose was analyzed for open fields, as well as a jaw-tracking VMAT plan. The agreement between the two methods was better than 0.15%. It was demonstrated that the agreement between measured and simulated relative output factors improves across all field sizes when backscatter is taken into account. Conclusion: For the first time, simulated monitor chamber dose and measured target current for an actual TrueBeam linac were incorporated in the MC absolute dose formalism. In conjunction with the use of MC inputs generated from post-delivery trajectory-log files, the present method allows accurate MC dose calculations, without resorting to any of the simplifying assumptions previously made in the True

  10. A Simplified Confinement Method (SCM) for Calculating Absolute Free Energies and Free Energy and Entropy Differences

    PubMed Central

    Ovchinnikov, Victor; Cecchini, Marco; Karplus, Martin

    2013-01-01

    A simple and robust formulation of the path-independent confinement method for the calculation of free energies is presented. The simplified confinement method (SCM) does not require matrix diagonalization or switching off the molecular force field, and has a simple convergence criterion. The method can be readily implemented in molecular dynamics programs with minimal or no code modifications. Because the confinement method is a special case of thermodynamic integration, it is trivially parallel over the integration variable. The accuracy of the method is demonstrated using a model diatomic molecule, for which exact results can be computed analytically. The method is then applied to the alanine dipeptide in vacuum, and to the α-helix ↔ β-sheet transition in a sixteen-residue peptide modeled in implicit solvent. The SCM requires less effort for the calculation of free energy differences than previous formulations because it does not require computing normal modes. The SCM has a diminished advantage for determining absolute free energy values, because it requires decreasing the MD integration step to obtain accurate results. An approximate confinement procedure is introduced, which can be used to estimate directly the configurational entropy difference between two macrostates, without the need for additional computation of the difference in the free energy or enthalpy. The approximation has similar convergence properties as the standard confinement method for the calculation of free energies. The use of the approximation requires about five times less wall-clock simulation time than that needed to compute enthalpy differences to similar precision from an MD trajectory. For the biomolecular systems considered in this study, the errors in the entropy approximation are under 10%. The approximation will therefore be most useful for cases in which the dominant source of error is insufficient sampling in the estimation of enthalpies, as arises in simulations of large

  11. Evaluation of activity through dynamic laser speckle using the absolute value of the differences

    NASA Astrophysics Data System (ADS)

    Braga, R. A.; Nobre, C. M. B.; Costa, A. G.; Sáfadi, T.; da Costa, F. M.

    2011-01-01

    When a material is illuminated with a laser beam, it is possible to verify a phenomenon known as dynamic speckle or biospeckle. It exhibits an interference image that contains lots of information about the process being analyzed, and one of its most important applications is determining the activity quantity from the materials under study. The numerical analysis of the dynamic speckle images can be carried out by means of a co-occurrence matrix (COM) that assembles the intensity distributions of a speckle pattern with regard to time. An operational method that is widely used on the biospeckle COMs is the inertia moment (IM). Some studies demonstrate that IM is more sensitive on analyzing processes that involve high activities or high frequencies if considering the spectral analysis of the phenomena. However, when this variation is not so intense, this method is less efficient. For low variations on the activity or low frequencies, qualitative methods such as wavelet based entropy and cross-spectrum analysis have presented better results; however, processes that are in the intermediate range of activity are not well covered for any of these techniques mentioned earlier. The contribution of this research is to present an alternative approach, based on the absolute value of the differences (AVD) when handling the biospeckle COM. By using AVD on the seed-drying process, was found that it is efficient on verifying the behavior of the intermediate frequencies. Accumulated sum test (Coates and Diggle) showed that AVD and IM are generated from the same stochastic process. Thus, AVD is useful as an alternative method in some cases or even as a complementary tool for analyzing the dynamic speckle, mainly when the information of the activity is not present on high frequencies.

  12. Total ionizing dose effects of domestic SiGe HBTs under different dose rates

    NASA Astrophysics Data System (ADS)

    Liu, Mo-Han; Lu, Wu; Ma, Wu-Ying; Wang, Xin; Guo, Qi; He, Cheng-Fa; Jiang, Ke; Li, Xiao-Long; Xun, Ming-Zhu

    2016-03-01

    The total ionizing radiation (TID) response of commercial NPN silicon germanium hetero-junction bipolar transistors (SiGe HBTs) produced domestically are investigated under dose rates of 800 mGy(Si)/s and 1.3 mGy(Si)/s with a Co-60 gamma irradiation source. The changes of transistor parameters such as Gummel characteristics, and excess base current before and after irradiation, are examined. The results of the experiments show that for the KT1151, the radiation damage is slightly different under the different dose rates after prolonged annealing, and shows a time dependent effect (TDE). For the KT9041, however, the degradations of low dose rate irradiation is higher than for the high dose rate, demonstrating that there is a potential enhanced low dose rate sensitivity (ELDRS) effect for the KT9041. The possible underlying physical mechanisms of the different dose rates responses induced by the gamma rays are discussed.

  13. Absolute Configuration from Different Multifragmentation Pathways in Light-Induced Coulomb Explosion Imaging.

    PubMed

    Pitzer, Martin; Kastirke, Gregor; Kunitski, Maksim; Jahnke, Till; Bauer, Tobias; Goihl, Christoph; Trinter, Florian; Schober, Carl; Henrichs, Kevin; Becht, Jasper; Zeller, Stefan; Gassert, Helena; Waitz, Markus; Kuhlins, Andreas; Sann, Hendrik; Sturm, Felix; Wiegandt, Florian; Wallauer, Robert; Schmidt, Lothar Ph H; Johnson, Allan S; Mazenauer, Manuel; Spenger, Benjamin; Marquardt, Sabrina; Marquardt, Sebastian; Schmidt-Böcking, Horst; Stohner, Jürgen; Dörner, Reinhard; Schöffler, Markus; Berger, Robert

    2016-08-18

    The absolute configuration of individual small molecules in the gas phase can be determined directly by light-induced Coulomb explosion imaging (CEI). Herein, this approach is demonstrated for ionization with a single X-ray photon from a synchrotron light source, leading to enhanced efficiency and faster fragmentation as compared to previous experiments with a femtosecond laser. In addition, it is shown that even incomplete fragmentation pathways of individual molecules from a racemic CHBrClF sample can give access to the absolute configuration in CEI. This leads to a significant increase of the applicability of the method as compared to the previously reported complete break-up into atomic ions and can pave the way for routine stereochemical analysis of larger chiral molecules by light-induced CEI. PMID:27298209

  14. Relative vs Absolute Antenna Calibrations: How, when, and why do they differ? A Comparison of Antenna Calibration Catalogs

    NASA Astrophysics Data System (ADS)

    Mader, G. L.; Bilich, A. L.

    2013-12-01

    Since 1994, NGS has computed relative antenna calibrations for more than 350 antenna models used by NGS customers and geodetic networks worldwide. In a 'relative' calibration, the antenna under test is calibrated relative to a standard reference antenna, the AOA D/M_T chokering. The majority of NGS calibrations have been made publicly available at the web site www.ngs.noaa.gov/ANTCAL as well as via the NGS master calibrations file ant_info.003. In the mid-2000's, institutions in Germany began distributing 'absolute' antenna calibrations, where the antenna under test is calibrated independent of any reference antenna. These calibration methods also overcame some limitations of relative calibrations by going to lower elevation angles and capturing azimuthal variations. Soon thereafter (2008), the International GNSS Service (IGS) initiated a geodetic community movement away from relative calibrations and toward absolute calibrations as the defacto standard. The IGS now distributes a catalog of absolute calibrations taken from several institutions, distributed as the IGS master calibrations file igs08.atx. The competing methods and files have raised many questions about when it is or is not valid to process a geodetic network using a combination of relative and absolute calibrations, and if/when it is valid to combine the NGS and IGS catalogs. Therefore, in this study, we compare the NGS catalog of relative calibrations against the IGS catalog of absolute calibrations. As of the writing of this abstract, there are 77 antenna+radome combinations which are common to both the NGS relative and IGS absolute catalogs, spanning 16 years of testing (1997 to present). 50 different antenna models and 8 manufacturers are represented in the study sample. We apply the widely-accepted standard method for converting relative to absolute, then difference the calibrations. Various statistics describe the observed differences between phase center offset (PCO), phase center variation

  15. Eosinophil count - absolute

    MedlinePlus

    Eosinophils; Absolute eosinophil count ... the white blood cell count to give the absolute eosinophil count. ... than 500 cells per microliter (cells/mcL). Normal value ranges may vary slightly among different laboratories. Talk ...

  16. Absolute pitch among American and Chinese conservatory students: prevalence differences, and evidence for a speech-related critical period.

    PubMed

    Deutsch, Diana; Henthorn, Trevor; Marvin, Elizabeth; Xu, HongShuai

    2006-02-01

    Absolute pitch is extremely rare in the U.S. and Europe; this rarity has so far been unexplained. This paper reports a substantial difference in the prevalence of absolute pitch in two normal populations, in a large-scale study employing an on-site test, without self-selection from within the target populations. Music conservatory students in the U.S. and China were tested. The Chinese subjects spoke the tone language Mandarin, in which pitch is involved in conveying the meaning of words. The American subjects were nontone language speakers. The earlier the age of onset of musical training, the greater the prevalence of absolute pitch; however, its prevalence was far greater among the Chinese than the U.S. students for each level of age of onset of musical training. The findings suggest that the potential for acquiring absolute pitch may be universal, and may be realized by enabling infants to associate pitches with verbal labels during the critical period for acquisition of features of their native language.

  17. Primary activity standardization of ⁹⁹Tc by three different absolute methods.

    PubMed

    da Cruz, Paulo A L; da Silva, Carlos J; Moreira, Denise S; Iwahara, Akira; Tauhata, Luiz; Lopes, Ricardo T

    2014-05-01

    The activity concentration of a solution of (99)Tc was absolutely determined by liquid scintillation measurements based on the triple-to double-coincidence ratio method (TDCR) and compared with the results given by 4πβ(LS)-γ(NaI) live-timed anticoincidence (with extending dead-time) and classical 4πβ(PC)-γ(NaI) coincidence counting systems based on using (60)Co as the efficiency-tracing radionuclide. The results of anticoincidence and coincidence counting are, respectively, 0.18% and 0.66% higher than the result from TDCR measurements, but they are consistent within uncertainties. PMID:24365467

  18. The performance of different propensity score methods for estimating absolute effects of treatments on survival outcomes: A simulation study

    PubMed Central

    Schuster, Tibor

    2014-01-01

    Observational studies are increasingly being used to estimate the effect of treatments, interventions and exposures on outcomes that can occur over time. Historically, the hazard ratio, which is a relative measure of effect, has been reported. However, medical decision making is best informed when both relative and absolute measures of effect are reported. When outcomes are time-to-event in nature, the effect of treatment can also be quantified as the change in mean or median survival time due to treatment and the absolute reduction in the probability of the occurrence of an event within a specified duration of follow-up. We describe how three different propensity score methods, propensity score matching, stratification on the propensity score and inverse probability of treatment weighting using the propensity score, can be used to estimate absolute measures of treatment effect on survival outcomes. These methods are all based on estimating marginal survival functions under treatment and lack of treatment. We then conducted an extensive series of Monte Carlo simulations to compare the relative performance of these methods for estimating the absolute effects of treatment on survival outcomes. We found that stratification on the propensity score resulted in the greatest bias. Caliper matching on the propensity score and a method based on earlier work by Cole and Hernán tended to have the best performance for estimating absolute effects of treatment on survival outcomes. When the prevalence of treatment was less extreme, then inverse probability of treatment weighting-based methods tended to perform better than matching-based methods. PMID:24463885

  19. Interplanetary crew doses and dose equivalents: variations among different bone marrow and skin sites

    NASA Astrophysics Data System (ADS)

    Hoff, J. L.; Townsend, L. W.; Zapp, E. N.

    2004-01-01

    Previously, calculations of bone marrow dose from the large solar particle event (SPE) of July 2000 were carried out using the BRYNTRN space radiation transport code and the computerized anatomical man (CAM) model. Results indicated that the dose for a bone marrow site in the mid-thigh might be twice as large as the dose for a site in the pelvis. These large variations may be significant for space radiation protection purposes, which traditionally use an average of many (typically 33) sites throughout the body. Other organs that cover large portions of the body, such as the skin, may also exhibit similar variations with doses differing from site to site. The skin traditionally uses an average of 32 sites throughout the body. Variations also occur from site to site among the dose equivalents, which may be important in determining stochastic effects. In this work, the magnitudes of dose and dose equivalent variations from site to site are investigated. The BRYNTRN and HZETRN transport codes and the CAM model are used to estimate bone marrow and skin doses and dose equivalents as a function of position in the body for several large solar particle events and annual galactic cosmic ray spectra from throughout the space era. These position-specific results are compared with the average values usually used for radiation protection purposes. Various thicknesses of aluminum shielding, representative of nominal spacecraft, are used in the analyses.

  20. Interplanetary Crew Doses and Dose Equivalents: Variations among Different Bone Marrow and Skin Sites

    NASA Astrophysics Data System (ADS)

    Hoff, J.; Townsend, L.; Zapp, E.

    Previously, calculations of bone marrow dose from the large solar particle event (SPE) of July 2000 were carried out using the BRYNTRN space radiation transport code and the Computerized Anatomical Man (CAM) model. Results indicated that the dose for a bone marrow site in the mid-thigh might be twice as large as the dose for a site in the pelvis. These large variations may be significant for space radiation protection purposes, which traditionally use an average of many (typically 33) sites throughout the body. Other organs that cover large portions of the body, such as the skin, may also exhibit similar variations with doses differing from site to site. The skin traditionally uses an average of 32 sites throughout the body. Variations also occur from site to site among the dose equivalents, which may be important in determining stochastic effects. In this work, the magnitudes of dose and dose equivalent variations from site to site are investigated. The BRYNTRN and HZETRN transport codes and the CAM model are used to estimate bone marrow and skin doses and dose equivalents as a function of position in the body for several large solar particle events and annual galactic cosmic ray (GCR) spectra from throughout the space era. These position-specific results are compared with the average values usually used for radiation protection purposes. Various thicknesses of aluminum shielding, representative of nominal spacecraft and SPE "storm shelter" designs, are used in the analyses.

  1. Differences in absolute and relative growth between two shell forms of Pinna nobilis (Mollusca: Bivalvia) along the Tunisian coastline

    NASA Astrophysics Data System (ADS)

    Rabaoui, Lotfi; Tlig-Zouari, Sabiha; Katsanevakis, Stelios; Belgacem, Walid; Hassine, Oum Kalthoum Ben

    2011-08-01

    This study investigated the absolute and relative growth patterns of the fan mussel Pinna nobilis along the Tunisian coastline, taking into consideration both the variability among different areas and between the two shell forms "combed" and "straight and wide". Five subpopulations of the species were sampled, one from northern, two from eastern and two from southern Tunisia. Various assumptions on the growth patterns were tested based on an information theory approach and multi-model inference. For absolute growth, the assumption of different growth patterns between the two shell forms of P. nobilis and no difference among subpopulations was the most supported by the data. For the same age, "straight and wide" individuals gained on average greater lengths than the "combed" individuals. The absolute growth of the species was found to be asymptotic and the logistic model was the one most supported by the data. As for the relative growth, apart from the classical allometric model Y = aXb, more complicated models of the form ln Y = f(ln X) that either assumed non-linearities or breakpoints were tested in combination with assumptions for possible differences between the two forms and among subpopulations. Among the eight studied relationships between morphometric characters, the classical allometric model was supported in only two cases, while in all other cases more complicated models were supported. Moreover, the assumption of different growth patterns between the two forms was supported in three cases and the assumption of different growth patterns among subpopulations in four cases. Although precise relationships between the morphometric plasticity of the fan mussel and environmental factors have not been proven in this paper, local small scale constraints might be responsible of the different growth patterns observed in the same locality. A possible co-action of genetic factors should be evaluated in the future.

  2. [The nootropic and anxiolytic properties of different doses of piracetam].

    PubMed

    Voronina, T A; Molodavkin, G M; Borlikova, G G; Ostrovskaia, R U; Tushmalova, N A; Naznamov, G G

    2000-01-01

    The effect of piracetam at various doses on the behavioral and electrophysiological characteristics was studied, including the development of passive and active avoidance conditional reflexes in rats, their behavior in conflict situations, and the transcallosal evoked response (TER) in rabbit brain. In the dose range from 50 to 300 mg/kg, piracetam improved the avoidance performance of both types and produced a dose-dependent increase in the TER amplitude, but did not affect the behavior of rats in conflict situations. As the drug dose was increased to 400-1000 mg/kg, the positive learning influence disappeared (sometimes the effect was even negative) and the TER increase changed to decrease. In contrast, the conflict situation tests revealed pronounced anxiolytic activity of piracetam at elevated doses. Thus, the nootropic and anxiolytic effects of piracetam (and, probably, of the other tranquilizers as well) do not coexist and are significantly shifted relative to one another on the dose scale, being probably realized via different mechanisms.

  3. Absolute quantification of a very virulent Marek's disease virus dynamic quantity and distributions in different tissues.

    PubMed

    Zhang, Zhenjie; Liu, Shaoqiong; Ma, Chengtai; Zhao, Peng; Cui, Zhizhong

    2015-06-01

    Chickens infected with Marek's disease virus (MDV) carry the virus consistently for a long time, which increases the incidence and rate of virus-induced multi-organ tumors and increases its potential for horizontal transmission. There is a positive correlation between very virulent (vv) MDV quantity and the pathology. The purpose of this study was to determine the vvMDV loads dynamics in different phases, and the correlation between the viral quantity and tumor development. We used a SYBR Green duplex real-time quantitative PCR (q-PCR) assay to detect and quantify MDV loads and distributions in different tissues, targeting the Eco-Q protein gene (meq) of the virus and the house-keeping ovotransferrin (ovo) gene of chickens. The q-PCR was performed using different tissue DNA preparations derived from chickens which were infected with 1,000 pfu of the SDWJ1302 strain and tissue samples were collected from control and MDV-infected birds on 7, 10, 15, 21, 28, 40, 60, and 90 d post-infection (DPI). The data indicated that the MDV genome was almost quantifiable in immune organs of infected chickens as early as 7 DPI, and the number of MDV genome copies in the blood and different organs peaked by 28 DPI, but then gradually decreased by 40 DPI. The levels of viral quantity in the lymphocytes, liver, and spleen were all higher than those in other organs, and that in the feather follicles was the highest among different phases of MDV infection. The vvMDV could still be detected in peripheral blood and tissues by 90 DPI, and the vast existence of virus will stimulate tissue destruction. The data provided further evidence of viral infection involving multi-organ distribution and mainly involving immune organ proliferation, resulting in immunosuppression. PMID:25834249

  4. Investigation of the Entrance Surface Dose and Dose to Different Organs in Lumbar Spine Imaging

    PubMed Central

    Sina, S; Zeinali, B; Karimipoorfard, M; Lotfalizadeh, F; Sadeghi, M; Zamani, E; Faghihi, R

    2014-01-01

    Background: Dose assessment using proper dosimeters is especially important in radiation protection optimization and imaging justification in diagnostic radiology. Objective: The aim of this study is to obtain the Entrance Skin Dose (ESD) of patients undergoing lumbar spine imaging using two thermoluminescence dosimeters TLD-100 (LiF: Mg, Ti) and GR-200 (LiF: Mg, Cu, P) and also to obtain the absorbed dose to different organs in lumbar spine imaging with several views. Methods: To measure the ESD values of the patients undergoing lumbar spine imaging, the two TLD types were put on their skin surface. The ESD values for different views of lumbar spine imaging were also measured by putting the TLDs at the surface of the Rando phantom. Several TLD chips were inserted inside different organs of Rando phantom to measure the absorbed dose to different organs in lumbar spine imaging. Results: The results indicate that there is a close agreement between the results of the two dosimeters. Based on the results of this experiment, the ESD dose of the 16 patients included in this study varied between 2.71 mGy and 26.29 mGy with the average of 11.89 mGy for TLD-100, and between 2.55 mGy and 27.41 mGy with the average of 12.32 mGy for GR-200 measurements. The ESDs obtained by putting the two types of TLDs at the surface of Rando phantom are in close agreement. Conclusion: According to the results, the GR200 has greater sensitivity than the TLD-100. PMID:25599058

  5. Improvement in carbofuran degradation by different Fenton's reagent dosing processes.

    PubMed

    Ma, Ying-Shih

    2011-11-01

    Attempts were made in this study to examine the efficiency of Fenton's reagent with different dosing processes and H(2)O(2) and Fe(2+) concentrations for the treatment of carbofuran wastewater. Carbofuran degradation, total organic carbon (TOC) removal and H(2)O(2) consumption were determined during the experiments. Increases in H(2)O(2) and Fe(2+) concentrations led to an increase in the degradation of carbofuran. Almost 100% of carbofuran could be degraded at pH 3, 120 mg L(-1) H(2)O(2), 24 mg L(-1) Fe(2+) and 30 minutes reaction time; removals of TOC were among 48.8%-53.3% under different dosing processes. A continuous dosing process was beneficial to improve the removal of TOC by Fenton's reagent. Rate constants of carbofuran degradation could be calculated by the first-order kinetics; increase in the Fenton's reagent generally increased the rate constants. Gas chromatography-mass spectrometry analysis found five degradation products by hydroxyl radicals attack. Thus, this study might offer an effective dosing way for carbofuran wastewater treatment by Fenton's reagent.

  6. Resolving Differences in Absolute Irradiance Measurements Between the SOHO/CELIAS/SEM and the SDO/EVE

    NASA Astrophysics Data System (ADS)

    Wieman, S. R.; Didkovsky, L. V.; Judge, D. L.

    2014-08-01

    The Solar EUV Monitor (SEM) onboard SOHO has measured absolute extreme ultraviolet (EUV) and soft X-ray solar irradiance nearly continuously since January 1996. The EUV Variability Experiment (EVE) on SDO, in operation since April of 2010, measures solar irradiance in a wide spectral range that encompasses the band passes (26 - 34 nm and 0.1 - 50 nm) measured by SOHO/SEM. However, throughout the mission overlap, irradiance values from these two instruments have differed by more than the combined stated uncertainties of the measurements. In an effort to identify the sources of these differences and eliminate them, we investigate in this work the effect of reprocessing the SEM data using a more accurate SEM response function (obtained from synchrotron measurements with a SEM sounding-rocket clone instrument taken after SOHO was already in orbit) and time-dependent, measured solar spectral distributions - i.e., solar reference spectra that were unavailable prior to the launch of the SDO. We find that recalculating the SEM data with these improved parameters reduces mean differences with the EVE measurements from about 20 % to less than 5 % in the 26 - 34 nm band, and from about 35 % to about 15 % for irradiances in the 0.1 - 7 nm band extracted from the SEM 0.1 - 50 nm channel.

  7. Direct dose mapping versus energy/mass transfer mapping for 4D dose accumulation: fundamental differences and dosimetric consequences

    NASA Astrophysics Data System (ADS)

    Li, Haisen S.; Zhong, Hualiang; Kim, Jinkoo; Glide-Hurst, Carri; Gulam, Misbah; Nurushev, Teamour S.; Chetty, Indrin J.

    2014-01-01

    The direct dose mapping (DDM) and energy/mass transfer (EMT) mapping are two essential algorithms for accumulating the dose from different anatomic phases to the reference phase when there is organ motion or tumor/tissue deformation during the delivery of radiation therapy. DDM is based on interpolation of the dose values from one dose grid to another and thus lacks rigor in defining the dose when there are multiple dose values mapped to one dose voxel in the reference phase due to tissue/tumor deformation. On the other hand, EMT counts the total energy and mass transferred to each voxel in the reference phase and calculates the dose by dividing the energy by mass. Therefore it is based on fundamentally sound physics principles. In this study, we implemented the two algorithms and integrated them within the Eclipse treatment planning system. We then compared the clinical dosimetric difference between the two algorithms for ten lung cancer patients receiving stereotactic radiosurgery treatment, by accumulating the delivered dose to the end-of-exhale (EE) phase. Specifically, the respiratory period was divided into ten phases and the dose to each phase was calculated and mapped to the EE phase and then accumulated. The displacement vector field generated by Demons-based registration of the source and reference images was used to transfer the dose and energy. The DDM and EMT algorithms produced noticeably different cumulative dose in the regions with sharp mass density variations and/or high dose gradients. For the planning target volume (PTV) and internal target volume (ITV) minimum dose, the difference was up to 11% and 4% respectively. This suggests that DDM might not be adequate for obtaining an accurate dose distribution of the cumulative plan, instead, EMT should be considered.

  8. Difference in dose-volumetric data between the analytical anisotropic algorithm, the dose-to-medium, and the dose-to-water reporting modes of the Acuros XB for lung stereotactic body radiation therapy.

    PubMed

    Mampuya, Wambaka A; Nakamura, Mitsuhiro; Hirose, Yoshinori; Kitsuda, Kenji; Ishigaki, Takashi; Mizowaki, Takashi; Hiraoka, Masahiro

    2016-01-01

    The purpose of this study was to evaluate the difference in dose-volumetric data between the analytical anisotropic algorithms (AAA) and the two dose reporting modes of the Acuros XB, namely, the dose to water (AXB_Dw) and dose to medium (AXB_Dm) in lung stereotactic body radiotherapy (SBRT). Thirty-eight plans were generated using the AXB_Dm in Eclipse Treatment Planning System (TPS) and then recalculated with the AXB_Dw and AAA, using identical beam setup. A dose of 50 Gy in 4 fractions was prescribed to the isocenter and the planning target volume (PTV) D95%. The isocenter was always inside the PTV. The following dose-volumetric parameters were evaluated; D2%, D50%, D95%, and D98% for the internal target volume (ITV) and the PTV. Two-tailed paired Student's t-tests determined the statistical significance. Although for most of the parameters evaluated, the mean differences observed between the AAA, AXB_Dm, and AXB_Dw were statistically significant (p < 0.05), absolute differences were rather small, in general less than 5% points. The maximum mean difference was observed in the ITV D50% between the AXB_Dm and the AAA and was 1.7% points under the isocenter prescription and 3.3% points under the D95 prescription. AXB_Dm produced higher values than AXB_Dw with differences ranging from 0.4 to 1.1% points under isocenter prescription and 0.0 to 0.7% points under the PTV D95% prescription. The differences observed under the PTV D95% prescription were larger compared to those observed for the isocenter prescription between AXB_Dm and AAA, AXB_Dm and AXB_Dw, and AXB_Dw and AAA. Although statistically significant, the mean differences between the three algorithms are within 3.3% points. PMID:27685138

  9. Difference in dose-volumetric data between the analytical anisotropic algorithm, the dose-to-medium, and the dose-to-water reporting modes of the Acuros XB for lung stereotactic body radiation therapy.

    PubMed

    Mampuya, Wambaka A; Nakamura, Mitsuhiro; Hirose, Yoshinori; Kitsuda, Kenji; Ishigaki, Takashi; Mizowaki, Takashi; Hiraoka, Masahiro

    2016-01-01

    The purpose of this study was to evaluate the difference in dose-volumetric data between the analytical anisotropic algorithms (AAA) and the two dose reporting modes of the Acuros XB, namely, the dose to water (AXB_Dw) and dose to medium (AXB_Dm) in lung stereotactic body radiotherapy (SBRT). Thirty-eight plans were generated using the AXB_Dm in Eclipse Treatment Planning System (TPS) and then recalculated with the AXB_Dw and AAA, using identical beam setup. A dose of 50 Gy in 4 fractions was prescribed to the isocenter and the planning target volume (PTV) D95%. The isocenter was always inside the PTV. The following dose-volumetric parameters were evaluated; D2%, D50%, D95%, and D98% for the internal target volume (ITV) and the PTV. Two-tailed paired Student's t-tests determined the statistical significance. Although for most of the parameters evaluated, the mean differences observed between the AAA, AXB_Dm, and AXB_Dw were statistically significant (p < 0.05), absolute differences were rather small, in general less than 5% points. The maximum mean difference was observed in the ITV D50% between the AXB_Dm and the AAA and was 1.7% points under the isocenter prescription and 3.3% points under the D95 prescription. AXB_Dm produced higher values than AXB_Dw with differences ranging from 0.4 to 1.1% points under isocenter prescription and 0.0 to 0.7% points under the PTV D95% prescription. The differences observed under the PTV D95% prescription were larger compared to those observed for the isocenter prescription between AXB_Dm and AAA, AXB_Dm and AXB_Dw, and AXB_Dw and AAA. Although statistically significant, the mean differences between the three algorithms are within 3.3% points.

  10. Absolute Summ

    NASA Astrophysics Data System (ADS)

    Phillips, Alfred, Jr.

    Summ means the entirety of the multiverse. It seems clear, from the inflation theories of A. Guth and others, that the creation of many universes is plausible. We argue that Absolute cosmological ideas, not unlike those of I. Newton, may be consistent with dynamic multiverse creations. As suggested in W. Heisenberg's uncertainty principle, and with the Anthropic Principle defended by S. Hawking, et al., human consciousness, buttressed by findings of neuroscience, may have to be considered in our models. Predictability, as A. Einstein realized with Invariants and General Relativity, may be required for new ideas to be part of physics. We present here a two postulate model geared to an Absolute Summ. The seedbed of this work is part of Akhnaton's philosophy (see S. Freud, Moses and Monotheism). Most important, however, is that the structure of human consciousness, manifest in Kenya's Rift Valley 200,000 years ago as Homo sapiens, who were the culmination of the six million year co-creation process of Hominins and Nature in Africa, allows us to do the physics that we do. .

  11. Morphological transformation of Syrian hamster embryo cells by low doses of fission neutrons delivered at different dose rates

    SciTech Connect

    Jones, C.A.; Sedita, B.A. ); Hill, C.K. . Cancer Research Lab.); Elkind, M.M. . Dept. of Radiology and Radiation Biology)

    1991-01-01

    Both induction of cell transformation and killing were examined with Syrian hamster embryo (SHE) fibroblasts exposed to low doses of JANUS fission-spectrum neutrons delivered at high (10.3 cGy/min) and low (0.43 and 0.086 cGy/min) dose rates. Second-passage cells were irradiated in mass cultures, then cloned over feeder cells. Morphologically transformed colonies were identified 8-10 days later. Cell killing was independent of dose rate, but the yield of transformation was greater after low-dose-rate irradiations. Decreasing the neutron dose-rate from 10.3 to 0.086 cGy/min resulted in a two- to threefold increase in the yield of transformation for neutron exposures below 50 cGy, and enhancement which was consistently observed in repetitive experiments in different radiosensitive SHE cell preparations. 43 refs., 5 figs., 1 tab.

  12. Clinical trial on different dose patterns of Shodhanartha Abhyantara Snehana

    PubMed Central

    Patil, Vasant C.; Thakar, Anup B.; Baghel, Madhav Singh

    2013-01-01

    Internal oleation (Snehana) is a major preparatory procedures performed before Bio-Purification (Shodhana). Oleation leads and decides the total outcome of the Bio-purification therapy; hence, standard guidelines are needed for performing the internal oleation in an effective manner and also for avoiding the inadequate and excess oleation. It is obligatory to start and increase the dose of lipids (Sneha) in appropriate and judicious way considering the bio-fire (Agni) and nature of bowel habit (Koshtha) of the subject. The outcome of Bio-Purification depends upon proper mobilization of Dosha from the periphery (Shakha) to gastrointestinal tract (Koshtha); which is achieved with the help of oleation therapy (Snehana Karma) and sudation therapy (Svedana Karma). This clinical study was carried out on 29 subjects to standardize the dose and duration of internal oleation and to develop the oleation grade for the assessment of internal oleation therapy. The selected subjects were randomly divided into two groups, in which group A was given fixed increase dose of ghee and in group B non-fixed increase dose was given. Results of this study show that the total percentage of oleation was 33.57% in group A and it was 45.28% in group B. Subjects of Group B (non-fixed dose schedule) have shown better oleation in all the aspects, i.e. duration, oleation grade, and purification grade. PMID:24250122

  13. Assessment of factors associated with dose differences between Japan and the United States.

    PubMed

    Arnold, F L; Fukunaga, S; Kusama, M; Matsuki, N; Ono, S

    2014-05-01

    Although it is well known that there are differences in approved doses between Japan and the United States, there has been no comprehensive research into the causes thereof. This study furthers the discussion of our previous investigation in 2010, with particular focus on pharmaceutical industry strategy and regulatory policy, among drugs approved in Japan between 2001 and 2009. Dose differences were observed in 73 of 190 drugs. Non-Japanese firms were more likely to have a similar dose approved between Japan and the United States, the association being more pronounced when limiting the analysis to drugs for which a Japanese dose-finding study was not conducted. Furthermore, dose differences were less frequent when non-Japanese efficacy data were included in the application data package. No relation between potential intrinsic ethnic difference and dose difference could be identified. The results suggest that the pathway of drug development is more strongly associated with dose difference than are drug characteristics.

  14. A graphite calorimeter for absolute measurements of absorbed dose to water: application in medium-energy x-ray filtered beams

    NASA Astrophysics Data System (ADS)

    Pinto, M.; Pimpinella, M.; Quini, M.; D'Arienzo, M.; Astefanoaei, I.; Loreti, S.; Guerra, A. S.

    2016-02-01

    The Italian National Institute of Ionizing Radiation Metrology (ENEA-INMRI) has designed and built a graphite calorimeter that, in a water phantom, has allowed the determination of the absorbed dose to water in medium-energy x-rays with generating voltages from 180 to 250 kV. The new standard is a miniaturized three-bodies calorimeter, with a disc-shaped core of 21 mm diameter and 2 mm thickness weighing 1.134 g, sealed in a PMMA waterproof envelope with air-evacuated gaps. The measured absorbed dose to graphite is converted into absorbed dose to water by means of an energy-dependent conversion factor obtained from Monte Carlo simulations. Heat-transfer correction factors were determined by FEM calculations. At a source-to-detector distance of 100 cm, a depth in water of 2 g cm-2, and at a dose rate of about 0.15 Gy min-1, results of calorimetric measurements of absorbed dose to water, D w, were compared to experimental determinations, D wK, obtained via an ionization chamber calibrated in terms of air kerma, according to established dosimetry protocols. The combined standard uncertainty of D w and D wK were estimated as 1.9% and 1.7%, respectively. The two absorbed dose to water determinations were in agreement within 1%, well below the stated measurement uncertainties. Advancements are in progress to extend the measurement capability of the new in-water-phantom graphite calorimeter to other filtered medium-energy x-ray qualities and to reduce the D w uncertainty to around 1%. The new calorimeter represents the first implementation of in-water-phantom graphite calorimetry in the kilovoltage range and, allowing independent determinations of D w, it will contribute to establish a robust system of absorbed dose to water primary standards for medium-energy x-ray beams.

  15. The performance of different propensity-score methods for estimating differences in proportions (risk differences or absolute risk reductions) in observational studies.

    PubMed

    Austin, Peter C

    2010-09-10

    Propensity score methods are increasingly being used to estimate the effects of treatments on health outcomes using observational data. There are four methods for using the propensity score to estimate treatment effects: covariate adjustment using the propensity score, stratification on the propensity score, propensity-score matching, and inverse probability of treatment weighting (IPTW) using the propensity score. When outcomes are binary, the effect of treatment on the outcome can be described using odds ratios, relative risks, risk differences, or the number needed to treat. Several clinical commentators suggested that risk differences and numbers needed to treat are more meaningful for clinical decision making than are odds ratios or relative risks. However, there is a paucity of information about the relative performance of the different propensity-score methods for estimating risk differences. We conducted a series of Monte Carlo simulations to examine this issue. We examined bias, variance estimation, coverage of confidence intervals, mean-squared error (MSE), and type I error rates. A doubly robust version of IPTW had superior performance compared with the other propensity-score methods. It resulted in unbiased estimation of risk differences, treatment effects with the lowest standard errors, confidence intervals with the correct coverage rates, and correct type I error rates. Stratification, matching on the propensity score, and covariate adjustment using the propensity score resulted in minor to modest bias in estimating risk differences. Estimators based on IPTW had lower MSE compared with other propensity-score methods. Differences between IPTW and propensity-score matching may reflect that these two methods estimate the average treatment effect and the average treatment effect for the treated, respectively.

  16. A graphite calorimeter for absolute measurements of absorbed dose to water: application in medium-energy x-ray filtered beams.

    PubMed

    Pinto, M; Pimpinella, M; Quini, M; D'Arienzo, M; Astefanoaei, I; Loreti, S; Guerra, A S

    2016-02-21

    The Italian National Institute of Ionizing Radiation Metrology (ENEA-INMRI) has designed and built a graphite calorimeter that, in a water phantom, has allowed the determination of the absorbed dose to water in medium-energy x-rays with generating voltages from 180 to 250 kV. The new standard is a miniaturized three-bodies calorimeter, with a disc-shaped core of 21 mm diameter and 2 mm thickness weighing 1.134 g, sealed in a PMMA waterproof envelope with air-evacuated gaps. The measured absorbed dose to graphite is converted into absorbed dose to water by means of an energy-dependent conversion factor obtained from Monte Carlo simulations. Heat-transfer correction factors were determined by FEM calculations. At a source-to-detector distance of 100 cm, a depth in water of 2 g cm(-2), and at a dose rate of about 0.15 Gy min(-1), results of calorimetric measurements of absorbed dose to water, D(w), were compared to experimental determinations, D wK, obtained via an ionization chamber calibrated in terms of air kerma, according to established dosimetry protocols. The combined standard uncertainty of D(w) and D(wK) were estimated as 1.9% and 1.7%, respectively. The two absorbed dose to water determinations were in agreement within 1%, well below the stated measurement uncertainties. Advancements are in progress to extend the measurement capability of the new in-water-phantom graphite calorimeter to other filtered medium-energy x-ray qualities and to reduce the D(w) uncertainty to around 1%. The new calorimeter represents the first implementation of in-water-phantom graphite calorimetry in the kilovoltage range and, allowing independent determinations of D(w), it will contribute to establish a robust system of absorbed dose to water primary standards for medium-energy x-ray beams. PMID:26841127

  17. Interoceptive conditioning in rats: effects of using a single training dose or a set of 5 different doses of nicotine.

    PubMed

    Pittenger, Steven T; Bevins, Rick A

    2013-12-01

    Interoceptive conditioning contributes to the tenacity of nicotine dependence. Previous research investigating nicotine as an interoceptive stimulus has typically employed administration of a single training dose of nicotine over an extended time. This approach has allowed for careful study of the nicotine stimulus. In humans, the nicotine stimulus is unlikely to be fixed across learning episodes. Thus, from a translational perspective, systematic variation of nicotine dose in training might better approximate interoceptive conditioning in humans. Notably, training with a class or set of discrete exteroceptive stimuli (e.g., different pictures of cars) produces interesting behavioral differences relative to training with a single stimulus. The present study sought to determine whether similar differences would occur if a set of nicotine stimuli were used in place of a single dose. To investigate this question, one group of male Sprague-Dawley rats was trained on a discriminated goal-tracking task with a set of nicotine doses (0.05, 0.125, 0.2, 0.275, and 0.35mg/kg). A second group received the standard protocol of training with a single nicotine dose (0.2mg/kg). On each nicotine session, there was intermittent access to liquid sucrose (26%) in a conditioning chamber. On intermixed saline sessions, sucrose was withheld. We examined acquisition, subsequent extinction, transfer of extinction, nicotine generalization, and mecamylamine blockade. Both groups reliably discriminated between nicotine and saline sessions, were sensitive to non-reinforcement, displayed transfer of extinction, demonstrated dose-dependent nicotine generalization, and responding was blocked by mecamylamine. There were no significant differences between the two groups. The unique nature of an interoceptive pharmacological stimulus and the challenges posed for studying the impact of training with a set of interoceptive stimuli are discussed.

  18. Comparison of different dose reduction system in computed tomography for orthodontic applications

    PubMed Central

    FANUCCI, E.; FIASCHETTI, V.; OTTRIA, L.; MATALONI, M; ACAMPORA, V.; LIONE, R.; BARLATTANI, A.; SIMONETTI, G.

    2011-01-01

    SUMMARY To correlate different CT system: MSCT (multislice computed tomography) with different acquisition parameters (100KV, 80KV), different reconstruction algorithm (ASIR) and CBCT (cone beam computed tomography) examination in terms of absorbed X-ray dose and diagnostic accuracy. 80 KV protocols compared with 100 KV protocols resulted in reduced total radiation dose without relevant loss of diagnostic image information and quality. CBCT protocols compared with 80 KV MSCT protocols resulted in reduced total radiation dose but loss of diagnostic image information and quality although no so relevant. In addition the new system applies to equipment ASIR applicable on MSCT allows 50% of the dose without compromising image quality. PMID:23285397

  19. Teaching Absolute Value Meaningfully

    ERIC Educational Resources Information Center

    Wade, Angela

    2012-01-01

    What is the meaning of absolute value? And why do teachers teach students how to solve absolute value equations? Absolute value is a concept introduced in first-year algebra and then reinforced in later courses. Various authors have suggested instructional methods for teaching absolute value to high school students (Wei 2005; Stallings-Roberts…

  20. Variations of Patient Doses in Interventional Examinations at Different Angiographic Units

    SciTech Connect

    Bor, Dogan Toklu, Tuerkay; Olgar, Turan; Sancak, Tanzer; Cekirge, Saruhan; Onal, Baran; Bilgic, Sadik

    2006-10-15

    Purpose. We analyzed doses for various angiographic procedures using different X-ray systems in order to assess dose variations. Methods. Dose-area product (DAP), skin doses from thermoluminescent dosimeters and air kerma measurements of 308 patients (239 diagnostic and 69 interventional) were assessed for five different angiographic units. All fluoroscopic and radiographic exposure parameters were recorded online for single and multiprojection studies. Radiation outputs of each X-ray system were also measured for all the modes of exposure using standard protocols for such measurements. Results. In general, the complexity of the angiographic procedure was found to be the most important reason for high radiation doses. Skill of the radiologist, management of the exposure parameters and calibration of the system are the other factors to be considered. Lateral cerebral interventional studies carry the highest risk for deterministic effects on the lens of the eye. Effective doses were calculated from DAP measurements and maximum fatal cancer risk factors were found for carotid studies. Conclusions. Interventional radiologists should measure patient doses for their examinations. If there is a lack of necessary instrumentation for this purpose, then published dose reports should be used in order to predict the dose levels from some of the exposure parameters. Patient dose information should include not only the measured quantity but also the measured radiation output of the X-ray unit and exposure parameters used during radiographic and fluoroscopic exposures.

  1. Neighbourhood socioeconomic inequalities in incidence of acute myocardial infarction: a cohort study quantifying age- and gender-specific differences in relative and absolute terms

    PubMed Central

    2012-01-01

    Background Socioeconomic status has a profound effect on the risk of having a first acute myocardial infarction (AMI). Information on socioeconomic inequalities in AMI incidence across age- gender-groups is lacking. Our objective was to examine socioeconomic inequalities in the incidence of AMI considering both relative and absolute measures of risk differences, with a particular focus on age and gender. Methods We identified all patients with a first AMI from 1997 to 2007 through linked hospital discharge and death records covering the Dutch population. Relative risks (RR) of AMI incidence were estimated by mean equivalent household income at neighbourhood-level for strata of age and gender using Poisson regression models. Socioeconomic inequalities were also shown within the stratified age-gender groups by calculating the total number of events attributable to socioeconomic disadvantage. Results Between 1997 and 2007, 317,564 people had a first AMI. When comparing the most deprived socioeconomic quintile with the most affluent quintile, the overall RR for AMI was 1.34 (95 % confidence interval (CI): 1.32 – 1.36) in men and 1.44 (95 % CI: 1.42 – 1.47) in women. The socioeconomic gradient decreased with age. Relative socioeconomic inequalities were most apparent in men under 35 years and in women under 65 years. The largest number of events attributable to socioeconomic inequalities was found in men aged 45–74 years and in women aged 65–84 years. The total proportion of AMIs that was attributable to socioeconomic inequalities in the Dutch population of 1997 to 2007 was 14 % in men and 18 % in women. Conclusions Neighbourhood socioeconomic inequalities were observed in AMI incidence in the Netherlands, but the magnitude across age-gender groups depended on whether inequality was expressed in relative or absolute terms. Relative socioeconomic inequalities were high in young persons and women, where the absolute burden of AMI was low. Absolute

  2. A comparison of absolute performance of different correlative and mechanistic species distribution models in an independent area.

    PubMed

    Shabani, Farzin; Kumar, Lalit; Ahmadi, Mohsen

    2016-08-01

    To investigate the comparative abilities of six different bioclimatic models in an independent area, utilizing the distribution of eight different species available at a global scale and in Australia. Global scale and Australia. We tested a variety of bioclimatic models for eight different plant species employing five discriminatory correlative species distribution models (SDMs) including Generalized Linear Model (GLM), MaxEnt, Random Forest (RF), Boosted Regression Tree (BRT), Bioclim, together with CLIMEX (CL) as a mechanistic niche model. These models were fitted using a training dataset of available global data, but with the exclusion of Australian locations. The capabilities of these techniques in projecting suitable climate, based on independent records for these species in Australia, were compared. Thus, Australia is not used to calibrate the models and therefore it is as an independent area regarding geographic locations. To assess and compare performance, we utilized the area under the receiver operating characteristic (ROC) curves (AUC), true skill statistic (TSS), and fractional predicted areas for all SDMs. In addition, we assessed satisfactory agreements between the outputs of the six different bioclimatic models, for all eight species in Australia. The modeling method impacted on potential distribution predictions under current climate. However, the utilization of sensitivity and the fractional predicted areas showed that GLM, MaxEnt, Bioclim, and CL had the highest sensitivity for Australian climate conditions. Bioclim calculated the highest fractional predicted area of an independent area, while RF and BRT were poor. For many applications, it is difficult to decide which bioclimatic model to use. This research shows that variable results are obtained using different SDMs in an independent area. This research also shows that the SDMs produce different results for different species; for example, Bioclim may not be good for one species but works better

  3. A comparison of absolute performance of different correlative and mechanistic species distribution models in an independent area.

    PubMed

    Shabani, Farzin; Kumar, Lalit; Ahmadi, Mohsen

    2016-08-01

    To investigate the comparative abilities of six different bioclimatic models in an independent area, utilizing the distribution of eight different species available at a global scale and in Australia. Global scale and Australia. We tested a variety of bioclimatic models for eight different plant species employing five discriminatory correlative species distribution models (SDMs) including Generalized Linear Model (GLM), MaxEnt, Random Forest (RF), Boosted Regression Tree (BRT), Bioclim, together with CLIMEX (CL) as a mechanistic niche model. These models were fitted using a training dataset of available global data, but with the exclusion of Australian locations. The capabilities of these techniques in projecting suitable climate, based on independent records for these species in Australia, were compared. Thus, Australia is not used to calibrate the models and therefore it is as an independent area regarding geographic locations. To assess and compare performance, we utilized the area under the receiver operating characteristic (ROC) curves (AUC), true skill statistic (TSS), and fractional predicted areas for all SDMs. In addition, we assessed satisfactory agreements between the outputs of the six different bioclimatic models, for all eight species in Australia. The modeling method impacted on potential distribution predictions under current climate. However, the utilization of sensitivity and the fractional predicted areas showed that GLM, MaxEnt, Bioclim, and CL had the highest sensitivity for Australian climate conditions. Bioclim calculated the highest fractional predicted area of an independent area, while RF and BRT were poor. For many applications, it is difficult to decide which bioclimatic model to use. This research shows that variable results are obtained using different SDMs in an independent area. This research also shows that the SDMs produce different results for different species; for example, Bioclim may not be good for one species but works better

  4. Comparative transcriptome analysis of rice seedlings induced by different doses of heavy ion radiation

    NASA Astrophysics Data System (ADS)

    Zhao, Qian; Sun, Yeqing; Wang, Wei

    2016-07-01

    Highly ionizing radiation (HZE) in space is considered as a main factor causing biological effects on plant seeds. To investigate the different effects on genome-wide gene expression of low-dose and high-dose ion radiation, we carried out ground-base carbon particle HZE experiments with different cumulative doses (0Gy, 0.2Gy, 2Gy) to rice seeds and then performed comparative transcriptome analysis of the rice seedlings. We identified a total of 2551 and 1464 differentially expressed genes (DEGs) in low-dose and high-dose radiation groups, respectively. Gene ontology analyses indicated that low-dose and high-dose ion radiation both led to multiple physiological and biochemical activities changes in rice. By Gene Ontology analyses, the results showed that only one process-oxidation reduction process was enriched in the biological process category after high-dose ion radiation, while more processes such as response to biotic stimulus, heme binding, tetrapyrrole binding, oxidoreductase activity, catalytic activity and oxidoreductase activity were significantly enriched after low-dose ion radiation. The results indicated that the rice plants only focused on the process of oxidation reduction to response to high-dose ion radiation, whereas it was a coordination of multiple biological processes to response to low-dose ion radiation. To elucidate the transcriptional regulation of radiation stress-responsive genes, we identified several DEGs-encoding TFs. AP2/EREBP, bHLH, C2H2, MYB and WRKY TF families were altered significantly in response to ion radiation. Mapman analysis speculated that the biological effects on rice seedlings caused by the radiation stress might share similar mechanisms with the biotic stress. Our findings highlight important alterations in the expression of radiation response genes, metabolic pathways, and TF-encoding genes in rice seedlings exposed to low-dose and high-dose ion radiation.

  5. Absolute measurement of species differences in sodium taurocholate cotransporting polypeptide (NTCP/Ntcp) and its modulation in cultured hepatocytes.

    PubMed

    Qiu, Xi; Bi, Yi-An; Balogh, Larissa M; Lai, Yurong

    2013-09-01

    Species differences among membrane transporters can be remarkable and difficult to properly assess by conventional methods. Herein, we employed the first use of stable isotope labeling in mammals or stable isotope-labeled peptides combined with mass spectrometry to identify species differences in sodium taurocholate cotransporting polypeptide (NTCP/Ntcp) protein expression in liver tissue and to characterize the modulation of protein expression in sandwich-cultured human (SCHH) and rat hepatocytes (SCRH). The lower limit of quantification was established to be 5 fmol on column with a standard curve that was linear up to 2000 fmol. The accuracy and precision were evaluated with three quality control samples and known amounts of synthetic proteotypic peptides that were spiked into the membrane protein extracts. The overall relative error and coefficient of variation were less than 10%. The expression of Ntcp in mouse and rat was significant higher than that in human (five-fold) and monkey (two-fold) and ranked as mouse > rat > monkey > human. In the cultured hepatocytes, although significant downregulation of Ntcp expression in SCRH at day 5 after the culture was detected, NTCP expression in SCHH was comparable to the suspension hepatocytes. The results suggested that NTCP/Ntcp modulation in cultured hepatocytes is species specific.

  6. Morphological changes induced by different doses of gamma irradiation in garlic sprouts

    NASA Astrophysics Data System (ADS)

    Pellegrini, C. N.; Croci, C. A.; Orioli, G. A.

    2000-03-01

    The objective of this work was to evaluate the effects of different doses of gamma rays applied in dormancy and post-dormancy on garlic bulbs in relation with some morphophysiological parameters. High (commercial) doses cause the complete inhibition of sprouting and mitosis (due to nuclear aberrations). Relatively low doses show no effects on bulbs but doses of 10 Gy applied in post-dormancy reduce sprouting and stop mitosis. This inhibition becomes noticeable from 150 days post-harvest onwards. Exogenous growth regulators can reverse these effects. Results may reinforce the good practice of radioinhibition processes in garlic.

  7. The effective dose of different scanning protocols using the Sirona GALILEOS® comfort CBCT scanner

    PubMed Central

    Bohay, R; Kaci, L; Barnett, R; Battista, J

    2015-01-01

    Objectives: To determine the effective dose and CT dose index (CTDI) for a range of imaging protocols using the Sirona GALILEOS® Comfort CBCT scanner (Sirona Dental Systems GmbH, Bensheim, Germany). Methods: Calibrated optically stimulated luminescence dosemeters were placed at 26 sites in the head and neck of a modified RANDO® phantom (The Phantom Laboratory, Greenwich, NY). Effective dose was calculated for 12 different scanning protocols. CTDI measurements were also performed to determine the dose–length product (DLP) and the ratio of effective dose to DLP for each scanning protocol. Results: The effective dose for a full maxillomandibular scan at 42 mAs was 102 ± 1 μSv and remained unchanged with varying contrast and resolution settings. This compares with 71 μSv for a maxillary scan and 76 μSv for a mandibular scan with identical milliampere-seconds (mAs) at high contrast and resolution settings. Conclusions: Changes to mAs and beam collimation have a significant influence on effective dose. Effective dose and DLP vary linearly with mAs. A collimated maxillary or mandibular scan decreases effective dose by approximately 29% and 24%, respectively, as compared with a full maxillomandibular scan. Changes to contrast and resolution settings have little influence on effective dose. This study provides data for setting individualized patient exposure protocols to minimize patient dose from ionizing radiation used for diagnostic or treatment planning tasks in dentistry. PMID:25358865

  8. Lunch-time food choices in preschoolers: Relationships between absolute and relative intakes of different food categories, and appetitive characteristics and weight.

    PubMed

    Carnell, S; Pryor, K; Mais, L A; Warkentin, S; Benson, L; Cheng, R

    2016-08-01

    Children's appetitive characteristics measured by parent-report questionnaires are reliably associated with body weight, as well as behavioral tests of appetite, but relatively little is known about relationships with food choice. As part of a larger preloading study, we served 4-5year olds from primary school classes five school lunches at which they were presented with the same standardized multi-item meal. Parents completed Child Eating Behavior Questionnaire (CEBQ) sub-scales assessing satiety responsiveness (CEBQ-SR), food responsiveness (CEBQ-FR) and enjoyment of food (CEBQ-EF), and children were weighed and measured. Despite differing preload conditions, children showed remarkable consistency of intake patterns across all five meals with day-to-day intra-class correlations in absolute and percentage intake of each food category ranging from 0.78 to 0.91. Higher CEBQ-SR was associated with lower mean intake of all food categories across all five meals, with the weakest association apparent for snack foods. Higher CEBQ-FR was associated with higher intake of white bread and fruits and vegetables, and higher CEBQ-EF was associated with greater intake of all categories, with the strongest association apparent for white bread. Analyses of intake of each food group as a percentage of total intake, treated here as an index of the child's choice to consume relatively more or relatively less of each different food category when composing their total lunch-time meal, further suggested that children who were higher in CEBQ-SR ate relatively more snack foods and relatively less fruits and vegetables, while children with higher CEBQ-EF ate relatively less snack foods and relatively more white bread. Higher absolute intakes of white bread and snack foods were associated with higher BMI z score. CEBQ sub-scale associations with food intake variables were largely unchanged by controlling for daily metabolic needs. However, descriptive comparisons of lunch intakes with

  9. Estimates of absorbed dose in different organs in children treated with radium for skin hemangiomas

    SciTech Connect

    Lundell, M.

    1994-12-01

    Between 1930 and 1959, more than 10,000 infants were treated at Radiumhemmet, Stockholm, with radium ({sup 226}Ra) needles and/or tubes for hemangioma of the skin. Absorbed dose to the brain, eye lenses, parotid glands, thyroid gland, breast enlarge, lungs, stomach, intestine, ovaries, testicles and bone marrow were calculated for each individual. The mean absorbed dose to the different organs ranged from 0.06 to 0.48 Gy. The highest absorbed dose was given to the breast (maximum 47.7 Gy). There was a wide dose range for each organ which was due mainly to differences in the distance between the applicator and the organ. The absorbed dose to all organs decreased on average by 32% during the study period. This was due to a 25% decrease in the treatment time and a change in the distribution of the treatment sites. 17 refs., 4 figs., 4 tabs.

  10. Association between absolute volumes of lung spared from low-dose irradiation and radiation-induced lung injury after intensity-modulated radiotherapy in lung cancer: a retrospective analysis

    PubMed Central

    Chen, Jinmei; Hong, Jinsheng; Zou, Xi; Lv, Wenlong; Guo, Feibao; Hong, Hualan; Zhang, Weijian

    2015-01-01

    The aim of this study was to investigate the association between absolute volumes of lung spared from low-dose irradiation and radiation-induced lung injury (RILI) after intensity-modulated radiotherapy (IMRT) for lung cancer. The normal lung relative volumes receiving greater than 5, 10, 20 and 30 Gy (V5–30) mean lung dose (MLD), and absolute volumes spared from greater than 5, 10, 20 and 30 Gy (AVS5–30) for the bilateral and ipsilateral lungs of 83 patients were recorded. Any association of clinical factors and dose–volume parameters with Grade ≥2 RILI was analyzed. The median follow-up was 12.3 months; 18 (21.7%) cases of Grade 2 RILI, seven (8.4%) of Grade 3 and two (2.4%) of Grade 4 were observed. Univariate analysis revealed the located lobe of the primary tumor. V5, V10, V20, MLD of the ipsilateral lung, V5, V10, V20, V30 and MLD of the bilateral lung, and AVS5 and AVS10 of the ipsilateral lung were associated with Grade ≥2 RILI (P < 0.05). Multivariate analysis indicated AVS5 of the ipsilateral lung was prognostic for Grade ≥2 RILI (P = 0.010, OR = 0.272, 95% CI: 0.102–0.729). Receiver operating characteristic curves indicated Grade ≥2 RILI could be predicted using AVS5 of the ipsilateral lung (area under curve, 0.668; cutoff value, 564.9 cm3; sensitivity, 60.7%; specificity, 70.4%). The incidence of Grade ≥2 RILI was significantly lower with AVS5 of the ipsilateral lung ≥564.9 cm3 than with AVS5 < 564.9 cm3 (P = 0.008). Low-dose irradiation relative volumes and MLD of the bilateral or ipsilateral lung were associated with Grade ≥2 RILI, and AVS5 of the ipsilateral lung was prognostic for Grade ≥2 RILI for lung cancer after IMRT. PMID:26454068

  11. Biphasic and triphasic dose responses in zebrafish embryos to low-dose 150 kV X-rays with different levels of hardness.

    PubMed

    Kong, Eva Yi; Cheng, Shuk Han; Yu, Kwan Ngok

    2016-07-01

    The in vivo low-dose responses of zebrafish (Danio rerio) embryos to 150 kV X-rays with different levels of hardness were examined through the number of apoptotic events revealed at 24 h post fertilization by vital dye acridine orange staining. Our results suggested that a triphasic dose response was likely a common phenomenon in living organisms irradiated by X-rays, which comprised an ultra-low-dose inhibition, low-dose stimulation and high-dose inhibition. Our results also suggested that the hormetic zone (or the stimulation zone) was shifted towards lower doses with application of filters. The non-detection of a triphasic dose response in previous experiments could likely be attributed to the use of hard X-rays, which shifted the hormetic zone into an unmonitored ultra-low-dose region. In such cases where the subhormetic zone was missed, a biphasic dose response would be reported instead.

  12. Biphasic and triphasic dose responses in zebrafish embryos to low-dose 150 kV X-rays with different levels of hardness

    PubMed Central

    Kong, Eva Yi; Cheng, Shuk Han; Yu, Kwan Ngok

    2016-01-01

    The in vivo low-dose responses of zebrafish (Danio rerio) embryos to 150 kV X-rays with different levels of hardness were examined through the number of apoptotic events revealed at 24 h post fertilization by vital dye acridine orange staining. Our results suggested that a triphasic dose response was likely a common phenomenon in living organisms irradiated by X-rays, which comprised an ultra-low-dose inhibition, low-dose stimulation and high-dose inhibition. Our results also suggested that the hormetic zone (or the stimulation zone) was shifted towards lower doses with application of filters. The non-detection of a triphasic dose response in previous experiments could likely be attributed to the use of hard X-rays, which shifted the hormetic zone into an unmonitored ultra-low-dose region. In such cases where the subhormetic zone was missed, a biphasic dose response would be reported instead. PMID:26951078

  13. ANALYSIS OF RESPIRATORY DESPOSITION DOSE OF INHALED AMBIENT AEROSOLS FOR DIFFERENT SIZE FRACTIONS

    EPA Science Inventory

    ANALYSIS OF RESPIRATORY DEPOSITION DOSE OF INHALED AMBIENT AEROSOLS FOR DIFFERENT SIZE FRACTIONS. Chong S. Kim, SC. Hu**, PA Jaques*, US EPA, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC 27711; **IIT Research Institute, Chicago, IL; *S...

  14. Effects of the difference in tube voltage of the CT scanner on dose calculation

    NASA Astrophysics Data System (ADS)

    Rhee, Dong Joo; Kim, Sung-woo; Jeong, Dong Hyeok; Moon, Young Min; Kim, Jung Ki

    2015-07-01

    Computed tomography (CT) measures the attenuation coefficient of an object and converts the value assigned to each voxel into a CT number. In radiation therapy, the CT number, which is directly proportional to the linear attenuation coefficient, must be converted to an electron density for radiation dose calculations for cancer treatment. However, if various tube voltages are applied to take the patient's CT image without applying the specific CT number to the electron density conversion curve, the accuracy of the dose calculation is not assured. In this study, changes in CT numbers for different materials due to changes in the tube voltage were demonstrated, and the dose calculation errors in the percentage depth dose (PDD), along with a clinical case were analyzed. The maximum dose difference in the PDD from the treatment planning system (TPS) dose calculation and from the Monte Carlo simulation were 1.3% and 1.1%, respectively, when applying the same CT number to the electron density conversion curve for the 80-kVp and 140-kVp images. In the clinical case, different CT number to electron density conversion curves at tube voltage of 80 kVp and 140 kVp were applied to the same image and the maximum differences in the mean, maximum, and minimum doses were 1.1%, 1.2%, and 1.0%, respectively, at the central region of the phantom and 0.6%, 0.9%, and 0.8%, respectively, at the peripheral region of the phantom.

  15. Interfractional trend analysis of dose differences based on 2D transit portal dosimetry

    NASA Astrophysics Data System (ADS)

    Persoon, L. C. G. G.; Nijsten, S. M. J. J. G.; Wilbrink, F. J.; Podesta, M.; Snaith, J. A. D.; Lustberg, T.; van Elmpt, W. J. C.; van Gils, F.; Verhaegen, F.

    2012-10-01

    Dose delivery of a radiotherapy treatment can be influenced by a number of factors. It has been demonstrated that the electronic portal imaging device (EPID) is valuable for transit portal dosimetry verification. Patient related dose differences can emerge at any time during treatment and can be categorized in two types: (1) systematic—appearing repeatedly, (2) random—appearing sporadically during treatment. The aim of this study is to investigate how systematic and random information appears in 2D transit dose distributions measured in the EPID plane over the entire course of a treatment and how this information can be used to examine interfractional trends, building toward a methodology to support adaptive radiotherapy. To create a trend overview of the interfractional changes in transit dose, the predicted portal dose for the different beams is compared to a measured portal dose using a γ evaluation. For each beam of the delivered fraction, information is extracted from the γ images to differentiate systematic from random dose delivery errors. From the systematic differences of a fraction for a projected anatomical structures, several metrics are extracted like percentage pixels with |γ| > 1. We demonstrate for four example cases the trends and dose difference causes which can be detected with this method. Two sample prostate cases show the occurrence of a random and systematic difference and identify the organ that causes the difference. In a lung cancer case a trend is shown of a rapidly diminishing atelectasis (lung fluid) during the course of treatment, which was detected with this trend analysis method. The final example is a breast cancer case where we show the influence of set-up differences on the 2D transit dose. A method is presented based on 2D portal transit dosimetry to record dose changes throughout the course of treatment, and to allow trend analysis of dose discrepancies. We show in example cases that this method can identify the causes of

  16. Evaluation of the medical exposure doses regarding dental examinations with different X-ray instruments

    NASA Astrophysics Data System (ADS)

    Liu, Yi-Chi; Chuang, Keh-Shih; Yu, Cheng-Ching; Chao, Jiunn-Hsing; Hsu, Fang-Yuh

    2015-11-01

    Modern dental X-ray examination that consists of traditional form, panorama, and cone-beamed 3D technologies is one of the most frequent diagnostic applications nowadays. This study used the Rando Phantom and thermoluminescence dosimeters (TLD) to measure the absorbed doses of radiosensitive organs recommended by International Commission on Radiological Protection (ICRP), and whole body effective doses which were delivered due to dental X-ray examination performed with different types of X-ray instrument. Besides, enamel samples which performed reading with Electronic Paramagnetic Resonance (EPR) procedure were also used to estimate the tooth doses. EPR is a dose reconstruction method of measuring free radicals induced by radiation exposure to the calcified tissue (mainly in the tooth enamel or bone) to evaluate the accepted high dose. The tooth doses estimated by TLD and EPR methods were compared. Relationships between the tooth doses and effective doses by dental X-ray examinations with different types of X-ray equipment were investigated in this work.

  17. Individual-dose distribution for the population in different regions with radioactive contamination

    SciTech Connect

    Keirim-Markus, I.B.; Kleshchenko, E.D.; Kushnereva, K.K.

    1995-09-01

    The reconstruction of individual doses as a result of the Chernobyl accident often relied on the method of EPR measurement from the enamel from extracted teeth. This method was used reliably, with individual confirmations of its indications being obtained. In determining the relatively small irradiation dose to the population, doubts arise because of the fact that the measured dose is often greater than the dose calculated by an indirect method---from external radiation fields at the location and the contents of radionuclides in foods. It is necessary, therefore, to perform an independent check of the results. In this paper, we describe one method for checking the reliability---comparing the measurements of the dose from several teeth in the same individual---in determining the dose from tooth enamel for the population of the Kamensk-Ural region of Sverdlovsk province. This group lived in the zone of passage for the eastern Ural radioactive wake in 1957. The error of the dose determination for different samples was different, since it depends on the mass and quality of the enamel obtained. The results presented show that the method of EPR dosimetry using the enamel of extracted teeth makes it possible to determine quite reliably the individual dose of external radiation from the background up to several Gy of the measurements. Our method compares measurements.

  18. Dose rate dependence for different dosimeters and detectors: TLD, OSL, EBT films, and diamond detectors

    SciTech Connect

    Karsch, L.; Beyreuther, E.; Burris-Mog, T.; Kraft, S.; Richter, C.; Zeil, K.; Pawelke, J.

    2012-05-15

    Purpose: The use of laser accelerators in radiation therapy can perhaps increase the low number of proton and ion therapy facilities in some years due to the low investment costs and small size. The laser-based acceleration technology leads to a very high peak dose rate of about 10{sup 11} Gy/s. A first dosimetric task is the evaluation of dose rate dependence of clinical dosimeters and other detectors. Methods: The measurements were done at ELBE, a superconductive linear electron accelerator which generates electron pulses with 5 ps length at 20 MeV. The different dose rates are reached by adjusting the number of electrons in one beam pulse. Three clinical dosimeters (TLD, OSL, and EBT radiochromic films) were irradiated with four different dose rates and nearly the same dose. A faraday cup, an integrating current transformer, and an ionization chamber were used to control the particle flux on the dosimeters. Furthermore two diamond detectors were tested. Results: The dosimeters are dose rate independent up to 410{sup 9} Gy/s within 2% (OSL and TLD) and up to 1510{sup 9} Gy/s within 5% (EBT films). The diamond detectors show strong dose rate dependence. Conclusions: TLD, OSL dosimeters, and EBT films are suitable for pulsed beams with a very high pulse dose rate like laser accelerated particle beams.

  19. A spatially encoded dose difference maximal intensity projection map for patient dose evaluation: A new first line patient quality assurance tool

    SciTech Connect

    Hu Weigang; Graff, Pierre; Boettger, Thomas; Pouliot, Jean; and others

    2011-04-15

    Purpose: To develop a spatially encoded dose difference maximal intensity projection (DD-MIP) as an online patient dose evaluation tool for visualizing the dose differences between the planning dose and dose on the treatment day. Methods: Megavoltage cone-beam CT (MVCBCT) images acquired on the treatment day are used for generating the dose difference index. Each index is represented by different colors for underdose, acceptable, and overdose regions. A maximal intensity projection (MIP) algorithm is developed to compress all the information of an arbitrary 3D dose difference index into a 2D DD-MIP image. In such an algorithm, a distance transformation is generated based on the planning CT. Then, two new volumes representing the overdose and underdose regions of the dose difference index are encoded with the distance transformation map. The distance-encoded indices of each volume are normalized using the skin distance obtained on the planning CT. After that, two MIPs are generated based on the underdose and overdose volumes with green-to-blue and green-to-red lookup tables, respectively. Finally, the two MIPs are merged with an appropriate transparency level and rendered in planning CT images. Results: The spatially encoded DD-MIP was implemented in a dose-guided radiotherapy prototype and tested on 33 MVCBCT images from six patients. The user can easily establish the threshold for the overdose and underdose. A 3% difference between the treatment and planning dose was used as the threshold in the study; hence, the DD-MIP shows red or blue color for the dose difference >3% or {<=}3%, respectively. With such a method, the overdose and underdose regions can be visualized and distinguished without being overshadowed by superficial dose differences. Conclusions: A DD-MIP algorithm was developed that compresses information from 3D into a single or two orthogonal projections while hinting the user whether the dose difference is on the skin surface or deeper.

  20. GaAs detectors irradiated by electrons at different dose rates

    NASA Astrophysics Data System (ADS)

    Sagatova, A.; Zatko, B.; Sedlackova, K.; Pavlovic, M.; Fulop, M.; Bohacek, P.; Necas, V.

    2014-12-01

    The radiation hardness of Semi-Insulating (SI) GaAs detectors against high-energy electrons was investigated. The detectors were irradiated by 5 MeV electrons. The influence of two irradiation parameters, the total absorbed dose (up to 24 kGy) and the applied dose rate (20, 40 and 80 kGy/h), on their spectrometric properties was studied. An 241Am gamma-ray source was used to evaluate the spectrometric properties. The applied dose has negatively affected the detector CCE (Charge Collection Efficiency) and has influenced also the energy resolution. Nevertheless, a global increase of detection efficiency with the dose was observed. Three different dose rates used during irradiation did not affect the CCE, but in the range of doses from 4 to 16 kGy an influence of the applied dose rate upon two other parameters was observed. With higher dose rates, a steeper increase in the detection efficiency and significant worsening of energy resolution were achieved.

  1. High and Low Doses of Ionizing Radiation Induce Different Secretome Profiles in a Human Skin Model

    SciTech Connect

    Zhang, Qibin; Matzke, Melissa M.; Schepmoes, Athena A.; Moore, Ronald J.; Webb-Robertson, Bobbie-Jo M.; Hu, Zeping; Monroe, Matthew E.; Qian, Weijun; Smith, Richard D.; Morgan, William F.

    2014-03-18

    It is postulated that secreted soluble factors are important contributors of bystander effect and adaptive responses observed in low dose ionizing radiation. Using multidimensional liquid chromatography-mass spectrometry based proteomics, we quantified the changes of skin tissue secretome – the proteins secreted from a full thickness, reconstituted 3-dimensional skin tissue model 48 hr after exposure to 3, 10 and 200 cGy of X-rays. Overall, 135 proteins showed statistical significant difference between the sham (0 cGy) and any of the irradiated groups (3, 10 or 200 cGy) on the basis of Dunnett adjusted t-test; among these, 97 proteins showed a trend of downregulation and 9 proteins showed a trend of upregulation with increasing radiation dose. In addition, there were 21 and 8 proteins observed to have irregular trends with the 10 cGy irradiated group either having the highest or the lowest level among all three radiated doses. Moreover, two proteins, carboxypeptidase E and ubiquitin carboxyl-terminal hydrolase isozyme L1 were sensitive to ionizing radiation, but relatively independent of radiation dose. Conversely, proteasome activator complex subunit 2 protein appeared to be sensitive to the dose of radiation, as rapid upregulation of this protein was observed when radiation doses were increased from 3, to 10 or 200 cGy. These results suggest that different mechanisms of action exist at the secretome level for low and high doses of ionizing radiation.

  2. Radiation Pneumonitis After Hypofractionated Radiotherapy: Evaluation of the LQ(L) Model and Different Dose Parameters

    SciTech Connect

    Borst, Gerben R.; Ishikawa, Masayori; Nijkamp, Jasper

    2010-08-01

    Purpose: To evaluate the linear quadratic (LQ) model for hypofractionated radiotherapy within the context of predicting radiation pneumonitis (RP) and to investigate the effect if a linear (L) model in the high region (LQL model) is used. Methods and Materials: The radiation doses used for 128 patients treated with hypofractionated radiotherapy were converted to the equivalent doses given in fractions of 2 Gy for a range of {alpha}/{beta} ratios (1 Gy to infinity) according to the LQ(L) model. For the LQL model, different cut-off values between the LQ model and the linear component were used. The Lyman model parameters were fitted to the events of RP grade 2 or higher to derive the normal tissue complication probability (NTCP). The lung dose was calculated as the mean lung dose and the percentage of lung volume (V) receiving doses higher than a threshold dose of xGy (V{sub x}). Results: The best NTCP fit was found if the mean lung dose, or V{sub x}, was calculated with an {alpha}/{beta} ratio of 3 Gy. The NTCP fit of other {alpha}/{beta} ratios and the LQL model were worse but within the 95% confidence interval of the NTCP fit of the LQ model with an {alpha}/{beta} ratio of 3 Gy. The V{sub 50} NTCP fit was better than the NTCP fit of lower threshold doses. Conclusions: For high fraction doses, the LQ model with an {alpha}/{beta} ratio of 3 Gy was the best method for converting the physical lung dose to predict RP.

  3. Gene interaction network analysis suggests differences between high and low doses of acetaminophen

    SciTech Connect

    Toyoshiba, Hiroyoshi . E-mail: toyoshiba.hiroyoshi@nies.go.jp; Sone, Hideko; Yamanaka, Takeharu; Parham, Frederick M.; Irwin, Richard D.; Boorman, Gary A.; Portier, Christopher J.

    2006-09-15

    Bayesian networks for quantifying linkages between genes were applied to detect differences in gene expression interaction networks between multiple doses of acetaminophen at multiple time points. Seventeen (17) genes were selected from the gene expression profiles from livers of rats orally exposed to 50, 150 and 1500 mg/kg acetaminophen (APAP) at 6, 24 and 48 h after exposure using a variety of statistical and bioinformatics approaches. The selected genes are related to three biological categories: apoptosis, oxidative stress and other. Gene interaction networks between all 17 genes were identified for the nine dose-time observation points by the TAO-Gen algorithm. Using k-means clustering analysis, the estimated nine networks could be clustered into two consensus networks, the first consisting of the low and middle dose groups, and the second consisting of the high dose. The analysis suggests that the networks could be segregated by doses and were consistent in structure over time of observation within grouped doses. The consensus networks were quantified to calculate the probability distribution for the strength of the linkage between genes connected in the networks. The quantifying analysis showed that, at lower doses, the genes related to the oxidative stress signaling pathway did not interact with the apoptosis-related genes. In contrast, the high-dose network demonstrated significant interactions between the oxidative stress genes and the apoptosis genes and also demonstrated a different network between genes in the oxidative stress pathway. The approaches shown here could provide predictive information to understand high- versus low-dose mechanisms of toxicity.

  4. Acute and repeated dose toxicity studies of different β-cyclodextrin-based nanosponge formulations.

    PubMed

    Shende, Pravin; Kulkarni, Yogesh A; Gaud, R S; Deshmukh, Kiran; Cavalli, Roberta; Trotta, Francesco; Caldera, Fabrizio

    2015-05-01

    Nanosponges (NS) show promising results in different fields such as medicine, agriculture, water purification, fire engineering and so on. The present study was designed to evaluate toxicity of different NS formulations (namely, S1-S6) synthesized with different cross-linking agents such as carbonyl diimidazole, pyromellitic dianhydride and hexamethylene diisocynate; and preparation methods in experimental animals. Acute and repeated dose toxicity studies of formulations were carried out as per OECD guidelines 423 and 407, respectively. For acute toxicity study, formulations were administered to female rats at doses of 300 and 2000 mg/kg orally. The general behaviour of the rats was continuously monitored for 1 h after dosing, periodically during the first 24 h and daily thereafter for a total of 14 days. On day 14, animals were fasted overnight, weighed, and sacrificed. After sacrification, animals were subjected to necropsy. For repeated dose toxicity study, rats of either sex were orally administered with formulations at the dose of 300 mg/kg per day for a period of 28 days. The maximally tolerated dose of all formulations was found to be 2000 mg/kg. Repeated administration of formulations for 28 days did not show any significant changes in haematological and biochemical parameters in experimental animals. These results indicate that the formulations are safe, when tested in experimental animals.

  5. Study of damage to red blood cells exposed to different doses of γ-ray irradiation

    PubMed Central

    Xu, Deyi; Peng, Mingxi; Zhang, Zhe; Dong, Guofei; Zhang, Yiqin; Yu, Hongwei

    2012-01-01

    Background. The aims of this research were to study alterations in the ultrastructure of red blood cells, the changes in concentrations of plasma electrolytes and the killing effect of lymphocytes in samples of blood exposed to different doses of γ-ray irradiation. Materials and methods. Blood samples were treated with different doses of γ-ray irradiation and then preserved for different periods. Specimens were prepared for standard electron microscopy and transmission electron microscopy. At the same time, changes in the concentrations of Na+, K+ and Cl− and pH values in the plasma as well as Fas and FasL expression of lymphocytes before and after irradiation were determined. Results. The proportions of reversibly and irreversibly transformed cells, for example, echinocytes, sphero-echinocytes, and degenerated forms, increased with increasing doses of irradiation and storage period, while the number of discocyte shaped red blood cells decreased. The change in K+ concentration was greater than that of Na+ or Cl− after irradiation and was dosage-dependent. Plasma pH was influenced by different doses of radiation and storage time. After exposure to 137Cs γ-irradiation, the expression of both Fas and FasL in lymphocytes differed significantly from that in the control group: the expression was positively correlated with irradiation dose (r=0.95, 0.96), but no significant difference in the Fas/FasL ratio was observed (P>0.05). Discussion. We conclude that the ultrastructure of red blood cells is not changed obviously by irradiation with some doses of γ-rays and various periods of storage. However, irradiation does have some dose-dependent and time-dependent adverse effects on the erythrocytes. PMID:22682338

  6. Mitigation of Atmospheric Delay in SAR Absolute Ranging Using Global Numerical Weather Prediction Data: Corner Reflector Experiments at 3 Different Test Sites

    NASA Astrophysics Data System (ADS)

    Cong, Xiaoying; Balss, Ulrich; Eineder, Michael

    2015-04-01

    The atmospheric delay due to vertical stratification, the so-called stratified atmospheric delay, has a great impact on both interferometric and absolute range measurements. In our current researches [1][2][3], centimeter-range accuracy has been proven based on Corner Reflector (CR) based measurements by applying atmospheric delay correction using the Zenith Path Delay (ZPD) corrections derived from nearby Global Positioning System (GPS) stations. For a global usage, an effective method has been introduced to estimate the stratified delay based on global 4-dimensional Numerical Weather Prediction (NWP) products: the direct integration method [4][5]. Two products, ERA-Interim and operational data, provided by European Centre for Medium-Range Weather Forecast (ECMWF) are used to integrate the stratified delay. In order to access the integration accuracy, a validation approach is investigated based on ZPD derived from six permanent GPS stations located in different meteorological conditions. Range accuracy at centimeter level is demonstrated using both ECMWF products. Further experiments have been carried out in order to determine the best interpolation method by analyzing the temporal and spatial correlation of atmospheric delay using both ECMWF and GPS ZPD. Finally, the integrated atmospheric delays in slant direction (Slant Path Delay, SPD) have been applied instead of the GPS ZPD for CR experiments at three different test sites with more than 200 TerraSAR-X High Resolution SpotLight (HRSL) images. The delay accuracy is around 1-3 cm depending on the location of test site due to the local water vapor variation and the acquisition time/date. [1] Eineder M., Minet C., Steigenberger P., et al. Imaging geodesy - Toward centimeter-level ranging accuracy with TerraSAR-X. Geoscience and Remote Sensing, IEEE Transactions on, 2011, 49(2): 661-671. [2] Balss U., Gisinger C., Cong X. Y., et al. Precise Measurements on the Absolute Localization Accuracy of TerraSAR-X on the

  7. Variation of indoor radon concentration and ambient dose equivalent rate in different outdoor and indoor environments.

    PubMed

    Stojanovska, Zdenka; Boev, Blazo; Zunic, Zora S; Ivanova, Kremena; Ristova, Mimoza; Tsenova, Martina; Ajka, Sorsa; Janevik, Emilija; Taleski, Vaso; Bossew, Peter

    2016-05-01

    Subject of this study is an investigation of the variations of indoor radon concentration and ambient dose equivalent rate in outdoor and indoor environments of 40 dwellings, 31 elementary schools and five kindergartens. The buildings are located in three municipalities of two, geologically different, areas of the Republic of Macedonia. Indoor radon concentrations were measured by nuclear track detectors, deployed in the most occupied room of the building, between June 2013 and May 2014. During the deploying campaign, indoor and outdoor ambient dose equivalent rates were measured simultaneously at the same location. It appeared that the measured values varied from 22 to 990 Bq/m(3) for indoor radon concentrations, from 50 to 195 nSv/h for outdoor ambient dose equivalent rates, and from 38 to 184 nSv/h for indoor ambient dose equivalent rates. The geometric mean value of indoor to outdoor ambient dose equivalent rates was found to be 0.88, i.e. the outdoor ambient dose equivalent rates were on average higher than the indoor ambient dose equivalent rates. All measured can reasonably well be described by log-normal distributions. A detailed statistical analysis of factors which influence the measured quantities is reported. PMID:26943159

  8. Assessment of leakage doses around the treatment heads of different linear accelerators.

    PubMed

    Lonski, P; Taylor, M L; Franich, R D; Harty, P; Kron, T

    2012-12-01

    Out-of-field doses to untargeted organs may have long-term detrimental health effects for patients treated with radiotherapy. It has been observed that equivalent treatments delivered to patients with different accelerators may result in significant differences in the out-of-field dose. In this work, the points of leakage dose are identified about the gantry of several treatment units. The origin of the observed higher doses is investigated. LiF:Mg,Cu,P thermoluminescent dosimetry has been employed to quantify the dose at a several points around the linac head of various linear accelerators (linacs): a Varian 600C, Varian 21-iX, Siemens Primus and Elekta Synergy-II. Comparisons are also made between different energy modes, collimator rotations and field sizes. Significant differences in leaked photon doses were identified when comparing the various linac models. The isocentric-waveguide 600C generally exhibits the lowest leakage directed towards the patient. The Siemens and Elekta models generally produce a greater leakage than the Varian models. The leakage 'hotspots' are evident on the gantry section housing the waveguide on the 21-iX. For all machines, there are significant differences in the x and y directions. Larger field sizes result in a greater leakage at the interface plate. There is a greater leakage around the waveguide when operating in a low-energy mode, but a greater leakage for the high-energy mode at the linac face. Of the vendors investigated, the Varian 600C showed the lowest average leakage dose. The Varian 21-iX showed double the dose of the 600C. The Elekta Synergy-II had on average four times the dose leakage than the 600C, and the Siemens Primus showed an average of five times that of the 600C. All vendors show strong differences in the x and y directions. The results offer the potential for patient-positioning strategies, linac choice and shielding strategies to reduce the leakage dose to patients.

  9. Radiation dose differences between digital mammography and digital breast tomosynthesis are dependent on breast thickness

    NASA Astrophysics Data System (ADS)

    Alakhras, Maram M.; Mello-Thoms, Claudia; Bourne, Roger; Rickard, Mary; Diffey, Jennifer; Brennan, Patrick C.

    2016-03-01

    Purpose To evaluate the radiation dose derived from digital mammography (DM) and digital breast tomosynthesis (DBT) at different tube current-exposure time product (mAs) and at 6 phantom thicknesses from 10 to 60 mm. Materials and Methods A total of 240 DM and DBT cranio-caudal (CC) phantom images were acquired at each thickness and at four exposure levels (the baseline mAs, 50%, 25% and 12.5% the baseline mAs). The incident Air Kerma (K) at the surface of the phantoms was measured using a solid state dosimeter. Mean Glandular Doses (MGD) were calculated for both modalities (DM and DBT). Results DBT dose was greater than that of DM for all mAs at each phantom thickness. For a breast thickness of 50 mm (close to average sized breast), the dose for DBT (2.32 mGy) was 13% higher than that for DM (2.05 mGy). The results also show that the difference in MGD between DM and DBT was less for the thicker compared with the thinner phantom, this difference being approximately a factor of 2.58 at 10 mm compared with a factor of 1.08 at 60 mm. While the MGD increased with increasing phantom thickness for both modalities, the dose increase with DBT was less than for DM, with the difference between 10 and 60 mm being a factor of 7 for DM and 3 for DBT. Conclusion The radiation dose from DBT was higher than that of DM and the difference in dose between DM and DBT decreases as phantom thickness increases.

  10. Tumor Induction in Mice After Localized Single- or Fractionated-Dose Irradiation: Differences in Tumor Histotype and Genetic Susceptibility Based on Dose Scheduling

    SciTech Connect

    Edmondson, Elijah F.; Hunter, Nancy R.; Weil, Michael M.; Mason, Kathryn A.

    2015-07-15

    Purpose: To investigate differences in tumor histotype, incidence, latency, and strain susceptibility in mice exposed to single-dose or clinically relevant, fractioned-dose γ-ray radiation. Methods and Materials: C3Hf/Kam and C57BL/6J mice were locally irradiated to the right hindlimb with either single large doses between 10 and 70 Gy or fractionated doses totaling 40 to 80 Gy delivered at 2-Gy/d fractions, 5 d/wk, for 4 to 8 weeks. The mice were closely evaluated for tumor development in the irradiated field for 800 days after irradiation, and all tumors were characterized histologically. Results: A total of 210 tumors were induced within the radiation field in 788 mice. An overall decrease in tumor incidence was observed after fractionated irradiation (16.4%) in comparison with single-dose irradiation (36.1%). Sarcomas were the predominant postirradiation tumor observed (n=201), with carcinomas occurring less frequently (n=9). The proportion of mice developing tumors increased significantly with total dose for both single-dose and fractionated schedules, and latencies were significantly decreased in mice exposed to larger total doses. C3Hf/Kam mice were more susceptible to tumor induction than C57BL/6J mice after single-dose irradiation; however, significant differences in tumor susceptibilities after fractionated radiation were not observed. For both strains of mice, osteosarcomas and hemangiosarcomas were significantly more common after fractionated irradiation, whereas fibrosarcomas and malignant fibrous histiocytomas were significantly more common after single-dose irradiation. Conclusions: This study investigated the tumorigenic effect of acute large doses in comparison with fractionated radiation in which both the dose and delivery schedule were similar to those used in clinical radiation therapy. Differences in tumor histotype after single-dose or fractionated radiation exposures provide novel in vivo evidence for differences in tumor

  11. Absolute nuclear material assay

    DOEpatents

    Prasad, Manoj K.; Snyderman, Neal J.; Rowland, Mark S.

    2012-05-15

    A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

  12. Absolute nuclear material assay

    DOEpatents

    Prasad, Manoj K.; Snyderman, Neal J.; Rowland, Mark S.

    2010-07-13

    A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

  13. Absolute Equilibrium Entropy

    NASA Technical Reports Server (NTRS)

    Shebalin, John V.

    1997-01-01

    The entropy associated with absolute equilibrium ensemble theories of ideal, homogeneous, fluid and magneto-fluid turbulence is discussed and the three-dimensional fluid case is examined in detail. A sigma-function is defined, whose minimum value with respect to global parameters is the entropy. A comparison is made between the use of global functions sigma and phase functions H (associated with the development of various H-theorems of ideal turbulence). It is shown that the two approaches are complimentary though conceptually different: H-theorems show that an isolated system tends to equilibrium while sigma-functions allow the demonstration that entropy never decreases when two previously isolated systems are combined. This provides a more complete picture of entropy in the statistical mechanics of ideal fluids.

  14. A Comparison of Four Indices for Combining Distance and Dose Differences

    SciTech Connect

    Thomas, Simon J.; Cowley, Ian R.

    2012-04-01

    Purpose: When one is comparing two dose distributions, a number of methods have been published to combine dose difference and distance to agreement into a single measure. Some have been defined as pass/fail indices and some as numeric indices. We show that the pass/fail indices can all be used to derive numeric indices, and we compare the results of using these indices to evaluate one-dimensional (1D) and three-dimensional (3D) dose distributions, with the aim of selecting the most appropriate index for use in different circumstances. Methods and Materials: The indices compared are the gamma index, the kappa index, the index in International Commission on Radiation Units and Measurements Report 83, and a box index. Comparisons are made for 1D and 3D distributions. The 1D distribution is chosen to have a variety of dose gradients. The 3D distribution is taken from a clinical treatment plan. The effect of offsetting distributions by known distances and doses is studied. Results: The International Commission on Radiation Units and Measurements Report 83 index causes large discontinuities unless the dose gradient cutoff is set to equal the ratio of the dose tolerance to the distance tolerance. If it is so set, it returns identical results to the kappa index. Where the gradient is very high or very low, all the indices studied in this article give similar results for the same tolerance values. For moderate gradients, they differ, with the box index being the least strict, followed by the gamma index, and with the kappa index being the most strict. Conclusions: If the clinical tolerances are much greater than the uncertainties of the measuring system, the kappa index should be used, with tolerance values determined by the clinical tolerances. In cases where the uncertainties of the measuring system dominate, the box index will be best able to determine errors in the delivery system.

  15. Responses of criterion variables to different supplemental doses of L-carnitine L-tartrate.

    PubMed

    Spiering, Barry A; Kraemer, William J; Vingren, Jakob L; Hatfield, Disa L; Fragala, Maren S; Ho, Jen-Yu; Maresh, Carl M; Anderson, Jeffrey M; Volek, Jeff S

    2007-02-01

    L-carnitine L-tartrate (LCLT) supplementation beneficially affects markers of postexercise metabolic stress and muscle damage. However, to date, no study has determined the dose response of LCLT to elicit such responses. Therefore, the purpose of this study was to determine the effects of different doses of LCLT on criterion variables previously shown to be responsive to LCLT supplementation. Eight healthy men (22 +/- 3 y, 174 +/- 5 cm, 83.0 +/- 15.3 kg) were supplemented with 0 g, 1 g, and 2 g of LCLT for 3 weeks and then performed a bout of resistance exercise (5 sets of 15-20 repetition maximum with a 2-min rest between sets) with associated blood draws. This procedure was performed in a balanced, randomized, repeated measures design. Serum carnitine concentrations increased (p < or = 0.05) following the 1 g and 2 g doses, with the 2-g dose providing the highest carnitine concentrations. The 1- and 2-g doses reduced postexercise serum hypoxanthine, serum xanthine oxidase, serum myoglobin, and perceived muscle soreness. In conclusion, both the 1- and 2-g doses were effective in mediating various markers of metabolic stress and of muscle soreness. Use of LCLT appears to attenuate metabolic stress and the hypoxic chain of events leading to muscle damage after exercise.

  16. The dose delivery effect of the different Beam ON interval in FFF SBRT: TrueBEAM

    NASA Astrophysics Data System (ADS)

    Tawonwong, T.; Suriyapee, S.; Oonsiri, S.; Sanghangthum, T.; Oonsiri, P.

    2016-03-01

    The purpose of this study is to determine the dose delivery effect of the different Beam ON interval in Flattening Filter Free Stereotactic Body Radiation Therapy (FFF-SBRT). The three 10MV-FFF SBRT plans (2 half rotating Rapid Arc, 9 to10 Gray/Fraction) were selected and irradiated in three different intervals (100%, 50% and 25%) using the RPM gating system. The plan verification was performed by the ArcCHECK for gamma analysis and the ionization chamber for point dose measurement. The dose delivery time of each interval were observed. For gamma analysis (2%&2mm criteria), the average percent pass of all plans for 100%, 50% and 25% intervals were 86.1±3.3%, 86.0±3.0% and 86.1±3.3%, respectively. For point dose measurement, the average ratios of each interval to the treatment planning were 1.012±0.015, 1.011±0.014 and 1.011±0.013 for 100%, 50% and 25% interval, respectively. The average dose delivery time was increasing from 74.3±5.0 second for 100% interval to 154.3±12.6 and 347.9±20.3 second for 50% and 25% interval, respectively. The same quality of the dose delivery from different Beam ON intervals in FFF-SBRT by TrueBEAM was illustrated. While the 100% interval represents the breath-hold treatment technique, the differences for the free-breathing using RPM gating system can be treated confidently.

  17. Immunological responses following experimental endobronchial infection of badgers (Meles meles) with different doses of Mycobacterium bovis.

    PubMed

    Lesellier, Sandrine; Corner, Leigh; Costello, Eamon; Sleeman, Paddy; Lyashchenko, Konstantin P; Greenwald, Rena; Esfandiari, Javan; Glyn Hewinson, R; Chambers, Mark; Gormley, Eamonn

    2009-01-15

    The Eurasian badger (Meles meles) is a wildlife reservoir for Mycobacterium bovis infection in Ireland and Great Britain and has been implicated in the transmission of tuberculosis to cattle. Vaccination of badgers is an option that could be used as part of a strategy to control the disease. In this study we used an endobronchial infection procedure to inoculate groups of badgers with three different doses (3x10(3), 2x10(2) and <10 Colony Forming Units (CFUs)) of M. bovis. After 17 weeks the disease status of each animal was determined by post-mortem pathology and culture for M. bovis. Each of the inoculum doses resulted in establishment of infection in the badgers. The cell-mediated immune (CMI) responses were measured by lymphocyte transformation assay (LTA) of peripheral blood mononuclear cells (PBMCs) cultured with bovine tuberculin (PPD-B). In each infected group the CMI responses increased with a kinetic profile corresponding to the delivered dose and the post-mortem pathology. The serological responses were measured by ELISA and a multi-antigen print immunoassay (MAPIA) in order to investigate any changes in the antigenic repertoire associated with different infective doses. In contrast to the CMI responses, the ELISA and MAPIA showed that the recognition of antigens by the badgers was intermittent and not strongly influenced by the dose of M. bovis.

  18. The impact of different dose response parameters on biologically optimized IMRT in breast cancer

    NASA Astrophysics Data System (ADS)

    Costa Ferreira, Brigida; Mavroidis, Panayiotis; Adamus-Górka, Magdalena; Svensson, Roger; Lind, Bengt K.

    2008-05-01

    The full potential of biologically optimized radiation therapy can only be maximized with the prediction of individual patient radiosensitivity prior to treatment. Unfortunately, the available biological parameters, derived from clinical trials, reflect an average radiosensitivity of the examined populations. In the present study, a breast cancer patient of stage I II with positive lymph nodes was chosen in order to analyse the effect of the variation of individual radiosensitivity on the optimal dose distribution. Thus, deviations from the average biological parameters, describing tumour, heart and lung response, were introduced covering the range of patient radiosensitivity reported in the literature. Two treatment configurations of three and seven biologically optimized intensity-modulated beams were employed. The different dose distributions were analysed using biological and physical parameters such as the complication-free tumour control probability (P+), the biologically effective uniform dose (\\bar{\\bar{D}} ), dose volume histograms, mean doses, standard deviations, maximum and minimum doses. In the three-beam plan, the difference in P+ between the optimal dose distribution (when the individual patient radiosensitivity is known) and the reference dose distribution, which is optimal for the average patient biology, ranges up to 13.9% when varying the radiosensitivity of the target volume, up to 0.9% when varying the radiosensitivity of the heart and up to 1.3% when varying the radiosensitivity of the lung. Similarly, in the seven-beam plan, the differences in P+ are up to 13.1% for the target, up to 1.6% for the heart and up to 0.9% for the left lung. When the radiosensitivity of the most important tissues in breast cancer radiation therapy was simultaneously changed, the maximum gain in outcome was as high as 7.7%. The impact of the dose response uncertainties on the treatment outcome was clinically insignificant for the majority of the simulated patients

  19. ANALYSIS OF RESPIRATORY DEPOSITION OF INHALED PARTICLES FOR DIFFERENT DOSE METRICS: COMPARISON OF NUMBER, SURFACE AREA AND MASS DOSE OF TYPICAL AMBIENT BI-MODAL AEROSOLS

    EPA Science Inventory

    ANALYSIS OF RESPIRATORY DEPOSITION OF INHALED PARTICLES FOR DIFFERENT DOSE METRICS: COMPARISON OF NUMBER, SURFACE AREA AND MASS DOSE OF TYPICAL AMBIENT BI-MODAL AEROSOLS.
    Chong S. Kim, SC. Hu*, PA Jaques*, US EPA, National Health and Environmental Effects Research Laboratory, ...

  20. ANALYSIS OF RESPIRATORY DEPOSITION OF INHALED AMBIENT AEROSOLS FOR DIFFERENT DOSE METRICS

    EPA Science Inventory

    ANALYSIS OF RESPIRATORY DEPOSITION OF INHALED AMBIENT AEROSOLS FOR DIFFERENT DOSE METRICS.
    Chong S. Kim, SC. Hu**, PA Jaques*, US EPA, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC 27711; **IIT Research Institute, Chicago, IL; *South...

  1. Dose distributions in phantoms irradiated in thermal columns of two different nuclear reactors.

    PubMed

    Gambarini, G; Agosteo, S; Altieri, S; Bortolussi, S; Carrara, M; Gay, S; Nava, E; Petrovich, C; Rosi, G; Valente, M

    2007-01-01

    In-phantom dosimetry studies have been carried out at the thermal columns of a thermal- and a fast-nuclear reactor for investigating: (a) the spatial distribution of the gamma dose and the thermal neutron fluence and (b) the accuracy at which the boron concentration should be estimated in an explanted organ of a boron neutron capture therapy patient. The phantom was a cylinder (11 cm in diameter and 12 cm in height) of tissue-equivalent gel. Dose images were acquired with gel dosemeters across the axial section of the phantom. The thermal neutron fluence rate was measured with activation foils in a few positions of this phantom. Dose and fluence rate profiles were also calculated with Monte Carlo simulations. The trend of these profiles do not show significant differences for the thermal columns considered in this work.

  2. Effects of different food doses on cadmium toxicity to Daphnia magna

    SciTech Connect

    Kluettgen, B.; Ratte, H.T. )

    1994-10-01

    Chronic toxicity tests were conducted with Daphnia magma using cadmium concentrations of 0, 0.5, 1, 2, and 5 [mu]g/L Cd with algae doses of 0.8, 4, 8, and 16 [center dot] 10[sup 6] cells/d of Chlorella saccharophila for each. In this way, the authors were able to determine the effects of cadmium on the life-table data of individuals, under different nutritional conditions. The development of juveniles was found to be inhibited by cadmium at low food doses, whereas body length and reproduction were strongly affected at higher food levels. The molting interval of adults and the development rate of embryos proved to be unaffected by cadmium. Cadmium-stressed animals lived longer than did the unstressed controls. The intrinsic rate of natural increase was generally reduced by cadmium, independent of the food dose.

  3. Degradation and annealing studies on gamma rays irradiated COTS PPD CISs at different dose rates

    NASA Astrophysics Data System (ADS)

    Wang, Zujun; Ma, Yingwu; Liu, Jing; Xue, Yuan; He, Baoping; Yao, Zhibin; Huang, Shaoyan; Liu, Minbo; Sheng, Jiangkun

    2016-06-01

    The degradation and annealing studies on Colbalt-60 gamma-rays irradiated commercial-off-the-shelf (COTS) pinned photodiode (PPD) CMOS image sensors (CISs) at the various dose rates are presented. The irradiation experiments of COTS PPD CISs are carried out at 0.3, 3.0 and 30.0 rad(Si)/s. The COTS PPD CISs are manufactured using a standard 0.18-μm CMOS technology with four-transistor pixel PPD architecture. The behavior of the tested CISs shows a remarkable degradation after irradiation and differs in the dose rates. The dark current, dark signal non-uniformity (DSNU), random noise, saturation output, signal to noise ratio (SNR), and dynamic range (DR) versus the total ionizing dose (TID) at the various dose rates are investigated. The tendency of dark current, DSNU, and random noise increase and saturation output, SNR, and DR to decrease at 3.0 rad(Si)/s are far greater than those at 0.3 and 30.0 rad(Si)/s. The damage mechanisms caused by TID irradiation at the various dose rates are also analyzed. The annealing tests are carried out at room temperature with unbiased conditions after irradiation.

  4. Comparative Study of Different {beta}-Radiation Doses for Preventing Pterygium Recurrence

    SciTech Connect

    Yamada, Takayuki; Mochizuki, Hideki; Ue, Takahiro; Kiuchi, Yoshiaki; Takahashi, Yasuhiro; Oinaka, Matsuyoshi

    2011-12-01

    Purpose: To compare the pterygium recurrence rates after treatment with two different {beta}-radiation doses. Methods and Materials: A total of 84 patients with a mean age of 63.0 {+-} 10.3 years (men, 48 eyes, and women, 47 eyes) and initially treated with {beta}-radiation after pterygium excision were recruited. The mean follow-up period was 49.9 {+-} 51.3 months. The patients were assigned to two dose groups: a high-dose (40 Gy) or a low-dose (20 Gy) group. The statistical significance of differences in patient age, pterygium size, and interval between surgery and radiotherapy were analyzed in the 20-Gy group using the Cox proportional hazard model at p < .05. Results: The high- and low-dose groups included 28 and 67 eyes, respectively. Pterygia recurred in 11 eyes, all in the low-dose group. The interval between surgery and radiotherapy was not a significant predictor of recurrence. Smaller pterygia had a lower risk of recurrence than pterygia that had encroached the pupillary area (pterygium located within one-third of the corneal radius from the limbus, corrected hazard ratio [HR], 0.069; 95% confidence interval [CI], 0.006-0.766; p = .030; pterygium extending beyond one-third of the corneal radius, corrected HR, 0.188; 95% CI, 0.018-0.696; p = 0.019; and pterygium reaching the pupillary area, corrected HR, 0.184; 95% CI, 0.036-0.929; p = .040). Older age was marginally significant as a negative predictor of recurrence (HR, 0.943; 95% CI, 0.887-1.003; p = .061). No scleromalacia developed during the follow-up period. Conclusions: {beta}-Radiation at 40 Gy was more efficacious than at 20 Gy in preventing pterygium recurrence without scleromalacia development, particularly for large-size pterygia and those in young patients.

  5. Differences in clinical disease and immune response of pigs challenged with a high-dose versus low-dose inoculum of porcine reproductive and respiratory syndrome virus.

    PubMed

    Loving, Crystal L; Brockmeier, Susan L; Vincent, Amy L; Lager, Kelly M; Sacco, Randy E

    2008-09-01

    Porcine reproductive and respiratory syndrome virus (PRRSV) continues to be an economically important infectious disease of swine. Mechanisms governing activation of the innate immune response to PRRSV remain to be elucidated. Virulence differences observed between PRRSV isolates have been attributed to replication ability in vivo, though immunogenic differences likely contribute to virulence also. The current study utilized a single PRRSV isolate given at two different challenge doses to investigate the effect of viral replication and load on immune responses, including type I interferon activation. Body temperature, viral load, antibody levels, cellular infiltration into pulmonary tissue, and the interferon response were measured in animals receiving either a low (10(2) CCID(50)) or high (10(6) CCID(50)) dose of inoculum to understand the role of challenge dose in acute immune responses. Initial PRRSV dose did not correlate with serum levels of PRRSV vRNA or antibody titers during the acute stage of infection (days 2-12 PI), but did have an effect on the immune response and mortality. Type I interferon responses, measured by transcriptional changes in IFN-beta, IFN-alpha, Mx, and PKR, were uniquely different when assessed relative to viral dose or cell type, but no overall trend existed to discern responses based on challenge dose. Serum IFN-gamma levels correlated with serum viral RNA load at day 19 PI. Overall, between days 2 and 12 PI, serum vRNA load was not significantly different between pigs challenged with a low or high dose of PRRSV. Animals receiving high-dose inoculum were viremic longer and eventually succumbed to respiratory disease. IFN-gamma may play a role in PRRSV pathogenesis, as serum levels increased significantly in pigs challenged with the high dose of PRRSV.

  6. Serious complications in experiments in which UV doses are affected by using different lamp heights

    NASA Astrophysics Data System (ADS)

    Flint, Stephan D.; Ryel, Ronald J.; Caldwell, Martyn M.

    2004-10-01

    Many experiments examining plant responses to enhanced UV-B radiation simply compare an enhanced UV-B radiation treatment with ambient UV-B (or no UV-B in most greenhouse and controlled environment studies). However, some experiments utilize multiple doses of UV-B radiation. A number of different techniques have been used to adjust the UV dose, each with advantages and disadvantages. One common technique is to place racks of fluorescent UV-B lamps at different heights above the plant canopy. A generally ignored consequence of this technique is that the pattern of shade which plants receive from the lamps is distributed differently over the course of the day at different lamp heights. To determine the effects of using lamps at different heights above the canopy, we grew three species (canola, sunflower, and maize) in the greenhouse under racks of unenergized lamps that were placed at two different heights above the plant canopy. Many plant growth characteristics differed between plants grown under the two lamp heights. These differences can potentially enhance or obscure true UV-B effects. Even more troubling is that changes in leaf mass per foliage area, which were observed in this experiment, could contribute to differences in plant UV-B sensitivity. We recommend the use of other techniques for achieving multiple doses of UV-B radiation. These range from simple and inexpensive approaches (wrapping individual fluorescent tubes in different layers of a neutral density filter such as cheese cloth) to more technical and expensive alternatives (electronically modulated lamp control systems). These choices should be determined by the goals of the particular experiment.

  7. Absolute biological needs.

    PubMed

    McLeod, Stephen

    2014-07-01

    Absolute needs (as against instrumental needs) are independent of the ends, goals and purposes of personal agents. Against the view that the only needs are instrumental needs, David Wiggins and Garrett Thomson have defended absolute needs on the grounds that the verb 'need' has instrumental and absolute senses. While remaining neutral about it, this article does not adopt that approach. Instead, it suggests that there are absolute biological needs. The absolute nature of these needs is defended by appeal to: their objectivity (as against mind-dependence); the universality of the phenomenon of needing across the plant and animal kingdoms; the impossibility that biological needs depend wholly upon the exercise of the abilities characteristic of personal agency; the contention that the possession of biological needs is prior to the possession of the abilities characteristic of personal agency. Finally, three philosophical usages of 'normative' are distinguished. On two of these, to describe a phenomenon or claim as 'normative' is to describe it as value-dependent. A description of a phenomenon or claim as 'normative' in the third sense does not entail such value-dependency, though it leaves open the possibility that value depends upon the phenomenon or upon the truth of the claim. It is argued that while survival needs (or claims about them) may well be normative in this third sense, they are normative in neither of the first two. Thus, the idea of absolute need is not inherently normative in either of the first two senses. PMID:23586876

  8. Absolute biological needs.

    PubMed

    McLeod, Stephen

    2014-07-01

    Absolute needs (as against instrumental needs) are independent of the ends, goals and purposes of personal agents. Against the view that the only needs are instrumental needs, David Wiggins and Garrett Thomson have defended absolute needs on the grounds that the verb 'need' has instrumental and absolute senses. While remaining neutral about it, this article does not adopt that approach. Instead, it suggests that there are absolute biological needs. The absolute nature of these needs is defended by appeal to: their objectivity (as against mind-dependence); the universality of the phenomenon of needing across the plant and animal kingdoms; the impossibility that biological needs depend wholly upon the exercise of the abilities characteristic of personal agency; the contention that the possession of biological needs is prior to the possession of the abilities characteristic of personal agency. Finally, three philosophical usages of 'normative' are distinguished. On two of these, to describe a phenomenon or claim as 'normative' is to describe it as value-dependent. A description of a phenomenon or claim as 'normative' in the third sense does not entail such value-dependency, though it leaves open the possibility that value depends upon the phenomenon or upon the truth of the claim. It is argued that while survival needs (or claims about them) may well be normative in this third sense, they are normative in neither of the first two. Thus, the idea of absolute need is not inherently normative in either of the first two senses.

  9. SU-E-T-633: Dose Differences in Lung Cancer SBRT: The Influences of MLC Width

    SciTech Connect

    Chen, J; Yin, Y

    2014-06-15

    Purpose: The aim is to compare the plan dose distribution of lung SBRT with MLCs in different width. Methods: Cases with phase INSCLC were enrolled. 9 cases were undergone 4D-CT scanning in the supine position with both arms raised. 3D-CT images without IV contrast were afterwards acquired with 3mm thickness and used for dose calculations. ITV was generated by using the inspiration and expiration images. The ITV can be expanded by geometric set-up uncertainty (5 mm) to generate the PTV. All chest normal tissues including chest wall were contoured by doctors. A total dose of 55 Gy will be given in 5 fractions within 10–14 days with an inter fraction interval of 2–3 days. Guided by the RTOG trial 3502 protocol, 11–13 non-coplanar fields with 6MV photon were arranged. Three types of MLCs with width of 3mm, 5mm and 10mm at isocenter position, were used separately to generate a CRT plan for each case. Monte Carlo algorithm was applied to dose calculation. All plans were adjusted as possible to meet the dose constraints. Dose-volume parameters from plans as followed were compared and analysized: PTV V55Gy, COMPTV D70% (70% of normalization dose), volume A (body minus PTV), and R100% and R50% (the ratio of x% of prescription dose isoline volume to PTV volume). Results: MLCs, 3mm and 5mm wide, played the identical roles on dosimetry of the plans, excluding the parameter volume A (p<0.05). On the contrary, MLC with width of 10mm was significantly inferior to the other two types on most parameters (p<0.05). For R50%, all types contributed equally (p>0.05). Conclusion: For lung cancer SBRT, MLC width had influence to dosimetry, especially in irradiation area. Small size MLC, e.g. 3mm and 5mm, are helpful to generate a high quality treatment plan, which could meet the strict criteria for targets and OAR.

  10. The effects of different doses of caffeine on endurance cycling time trial performance.

    PubMed

    Desbrow, Ben; Biddulph, Caren; Devlin, Brooke; Grant, Gary D; Anoopkumar-Dukie, Shailendra; Leveritt, Michael D

    2012-01-01

    This study investigated the effects of two different doses of caffeine on endurance cycle time trial performance in male athletes. Using a randomised, placebo-controlled, double-blind crossover study design, sixteen well-trained and familiarised male cyclists (Mean ± s: Age = 32.6 ± 8.3 years; Body mass = 78.5 ± 6.0 kg; Height = 180.9 ± 5.5 cm VO2(peak) = 60.4 ± 4.1 ml x kg(-1) x min(-1)) completed three experimental trials, following training and dietary standardisation. Participants ingested either a placebo, or 3 or 6 mg x kg(-1) body mass of caffeine 90 min prior to completing a set amount of work equivalent to 75% of peak sustainable power output for 60 min. Exercise performance was significantly (P < 0.05) improved with both caffeine treatments as compared to placebo (4.2% with 3 mg x kg(-1) body mass and 2.9% with 6 mg x kg(-1) body mass). The difference between the two caffeine doses was not statistically significant (P = 0.24). Caffeine ingestion at either dose resulted in significantly higher heart rate values than the placebo conditions (P < 0.05), but no statistically significant treatment effects in ratings of perceived exertion (RPE) were observed (P = 0.39). A caffeine dose of 3 mg x kg(-1) body mass appears to improve cycling performance in well-trained and familiarised athletes. Doubling the dose to 6 mg x kg(-1) body mass does not confer any additional improvements in performance.

  11. Differences in Radiation Dose Response between Small and Large Intestinal Crypts.

    PubMed

    Otsuka, Kensuke; Suzuki, Keiji

    2016-09-01

    The protection of intestinal epithelial cells from the lethal effects induced by high-dose radiation is an important issue in radiotherapy and in the treatment of acute radiation syndrome. However, the effects of middle- and low-dose radiation on intestinal epithelial cells remain unclear. Because the accumulation of DNA damage in intestinal stem cells may be crucial for the development of cancer-initiating cells, it is important to understand the kinetics of DNA repair and tissue response (which are involved in the elimination of damaged cells and tissue injury repair) to middle- to low-dose irradiation. In this study, mice were X-ray irradiated with 0.1, 1 or 4 Gy, after which the small intestine (duodenum and ileum) and colon were harvested from the animals. DNA damage repair and the elimination of damaged cells were quantified by measuring the number of foci of 53BP1, a surrogate marker for DNA double-strand breaks. Tissue-proliferative response was evaluated by determining the number of Ki-67(+) and mitotic cells. Intra-crypt response differed considerably between the small intestine and the colon. In the small intestine, 53BP1 foci were detected immediately after irradiation, but rapidly disappeared thereafter, especially noticeable in Lgr5(+) stem cells. Cellular growth was temporally arrested; however, cell numbers and mitotic cell numbers in the crypt did not change. The kinetics of DNA damage repair in Lgr5(+) stem cells were similar to those in the small intestines, while the colon was more susceptible to radiation-induced damage. Preferential cell loss in the lower crypt was clearly observed in the colon; and after low-dose X-ray irradiation, only the colon exhibited considerably reduced cell numbers and dramatic induction of mitosis. These results suggest that differences in radiation dose response between the small and the large intestine may depend on the growth activity of stem cells after DNA repair.

  12. Differences in Radiation Dose Response between Small and Large Intestinal Crypts.

    PubMed

    Otsuka, Kensuke; Suzuki, Keiji

    2016-09-01

    The protection of intestinal epithelial cells from the lethal effects induced by high-dose radiation is an important issue in radiotherapy and in the treatment of acute radiation syndrome. However, the effects of middle- and low-dose radiation on intestinal epithelial cells remain unclear. Because the accumulation of DNA damage in intestinal stem cells may be crucial for the development of cancer-initiating cells, it is important to understand the kinetics of DNA repair and tissue response (which are involved in the elimination of damaged cells and tissue injury repair) to middle- to low-dose irradiation. In this study, mice were X-ray irradiated with 0.1, 1 or 4 Gy, after which the small intestine (duodenum and ileum) and colon were harvested from the animals. DNA damage repair and the elimination of damaged cells were quantified by measuring the number of foci of 53BP1, a surrogate marker for DNA double-strand breaks. Tissue-proliferative response was evaluated by determining the number of Ki-67(+) and mitotic cells. Intra-crypt response differed considerably between the small intestine and the colon. In the small intestine, 53BP1 foci were detected immediately after irradiation, but rapidly disappeared thereafter, especially noticeable in Lgr5(+) stem cells. Cellular growth was temporally arrested; however, cell numbers and mitotic cell numbers in the crypt did not change. The kinetics of DNA damage repair in Lgr5(+) stem cells were similar to those in the small intestines, while the colon was more susceptible to radiation-induced damage. Preferential cell loss in the lower crypt was clearly observed in the colon; and after low-dose X-ray irradiation, only the colon exhibited considerably reduced cell numbers and dramatic induction of mitosis. These results suggest that differences in radiation dose response between the small and the large intestine may depend on the growth activity of stem cells after DNA repair. PMID:27556352

  13. Dose differences in intensity-modulated radiotherapy plans calculated with pencil beam and Monte Carlo for lung SBRT.

    PubMed

    Liu, Han; Zhuang, Tingliang; Stephans, Kevin; Videtic, Gregory; Raithel, Stephen; Djemil, Toufik; Xia, Ping

    2015-11-08

    For patients with medically inoperable early-stage non-small cell lung cancer (NSCLC) treated with stereotactic body radiation therapy, early treatment plans were based on a simpler dose calculation algorithm, the pencil beam (PB) calculation. Because these patients had the longest treatment follow-up, identifying dose differences between the PB calculated dose and Monte Carlo calculated dose is clinically important for understanding of treatment outcomes. Previous studies found significant dose differences between the PB dose calculation and more accurate dose calculation algorithms, such as convolution-based or Monte Carlo (MC), mostly for three-dimensional conformal radiotherapy (3D CRT) plans. The aim of this study is to investigate whether these observed dose differences also exist for intensity-modulated radiotherapy (IMRT) plans for both centrally and peripherally located tumors. Seventy patients (35 central and 35 peripheral) were retrospectively selected for this study. The clinical IMRT plans that were initially calculated with the PB algorithm were recalculated with the MC algorithm. Among these paired plans, dosimetric parameters were compared for the targets and critical organs. When compared to MC calculation, PB calculation overestimated doses to the planning target volumes (PTVs) of central and peripheral tumors with different magnitudes. The doses to 95% of the central and peripheral PTVs were overestimated by 9.7% ± 5.6% and 12.0% ± 7.3%, respectively. This dose overestimation did not affect doses to the critical organs, such as the spinal cord and lung. In conclusion, for NSCLC treated with IMRT, dose differences between the PB and MC calculations were different from that of 3D CRT. No significant dose differences in critical organs were observed between the two calculations.

  14. Dose differences in intensity-modulated radiotherapy plans calculated with pencil beam and Monte Carlo for lung SBRT.

    PubMed

    Liu, Han; Zhuang, Tingliang; Stephans, Kevin; Videtic, Gregory; Raithel, Stephen; Djemil, Toufik; Xia, Ping

    2015-01-01

    For patients with medically inoperable early-stage non-small cell lung cancer (NSCLC) treated with stereotactic body radiation therapy, early treatment plans were based on a simpler dose calculation algorithm, the pencil beam (PB) calculation. Because these patients had the longest treatment follow-up, identifying dose differences between the PB calculated dose and Monte Carlo calculated dose is clinically important for understanding of treatment outcomes. Previous studies found significant dose differences between the PB dose calculation and more accurate dose calculation algorithms, such as convolution-based or Monte Carlo (MC), mostly for three-dimensional conformal radiotherapy (3D CRT) plans. The aim of this study is to investigate whether these observed dose differences also exist for intensity-modulated radiotherapy (IMRT) plans for both centrally and peripherally located tumors. Seventy patients (35 central and 35 peripheral) were retrospectively selected for this study. The clinical IMRT plans that were initially calculated with the PB algorithm were recalculated with the MC algorithm. Among these paired plans, dosimetric parameters were compared for the targets and critical organs. When compared to MC calculation, PB calculation overestimated doses to the planning target volumes (PTVs) of central and peripheral tumors with different magnitudes. The doses to 95% of the central and peripheral PTVs were overestimated by 9.7% ± 5.6% and 12.0% ± 7.3%, respectively. This dose overestimation did not affect doses to the critical organs, such as the spinal cord and lung. In conclusion, for NSCLC treated with IMRT, dose differences between the PB and MC calculations were different from that of 3D CRT. No significant dose differences in critical organs were observed between the two calculations. PMID:26699560

  15. Absolute neutrino mass measurements

    SciTech Connect

    Wolf, Joachim

    2011-10-06

    The neutrino mass plays an important role in particle physics, astrophysics and cosmology. In recent years the detection of neutrino flavour oscillations proved that neutrinos carry mass. However, oscillation experiments are only sensitive to the mass-squared difference of the mass eigenvalues. In contrast to cosmological observations and neutrino-less double beta decay (0v2{beta}) searches, single {beta}-decay experiments provide a direct, model-independent way to determine the absolute neutrino mass by measuring the energy spectrum of decay electrons at the endpoint region with high accuracy.Currently the best kinematic upper limits on the neutrino mass of 2.2eV have been set by two experiments in Mainz and Troitsk, using tritium as beta emitter. The next generation tritium {beta}-experiment KATRIN is currently under construction in Karlsruhe/Germany by an international collaboration. KATRIN intends to improve the sensitivity by one order of magnitude to 0.2eV. The investigation of a second isotope ({sup 137}Rh) is being pursued by the international MARE collaboration using micro-calorimeters to measure the beta spectrum. The technology needed to reach 0.2eV sensitivity is still in the R and D phase. This paper reviews the present status of neutrino-mass measurements with cosmological data, 0v2{beta} decay and single {beta}-decay.

  16. An evaluation of different doses of soluble aspirin and aspirin tablets in postoperative dental pain.

    PubMed Central

    Holland, I S; Seymour, R A; Ward-Booth, R P; Ord, R A; Lim, K L; Hoare, R C

    1988-01-01

    1. The efficacy of three different single doses (600, 900 and 1200 mg of soluble aspirin and aspirin tablets) was determined in a randomized placebo-controlled parallel study in 140 patients (70 females) with postoperative pain after removal of impacted third molars. 2. Patients treated with soluble aspirin 600 mg, 900 mg, 1200 mg and aspirin tablet 1200 mg reported significantly less pain (P less than 0.01) throughout the investigation period than those treated with placebo. 3. Overall pain scores after treatment with aspirin tablets 600 and 900 mg did not differ significantly from those after treatment with placebo (P greater than 0.05). 4. On a comparative dose basis, soluble aspirin was significantly more potent (P less than 0.05) than aspirin tablets. PMID:3190996

  17. Changes in soil aggregate stability under different irrigation doses of waste water

    NASA Astrophysics Data System (ADS)

    Morugán, Alicia; García-Orenes, Fuensanta; Mataix-Solera, Jorge; Arcenegui, Victoria; Bárcenas, Gema

    2010-05-01

    Freshwater availability and soil degradation are two of the most important environmental problems in the Mediterranean area acerbated by incorrect agricultural use of irrigation in which organic matter is not correctly managed, the use of low quality water for irrigation, and the inefficiency of dose irrigation. For these reasons strategies for saving water and for the restoration of the mean properties of soil are necessary. The use of treated waste water for the irrigation of agricultural land could be a good solution to these problems, as it reduces the utilization of fresh water and could potentially improve key soil properties. In this work we have been studying, for more than three years, the effects on soil properties of different doses of irrigation with waste water. Here we show the results on aggregate stability. The study is located in an agricultural area at Biar (Alicante, SE of Spain), with a crop of grape (Vitis labrusca). Three types of waters are being used in the irrigation of the soil: fresh water (control) (TC), and treated waste water from secondary (T2) and tertiary treatment (T3). Three different doses of irrigation have been applied to fit the efficiency of the irrigation to the crop and soil type: D10 (10 L m-2 every week during 17 months), D50 (50 L m-2 every fifteen days during 14 moths) and D30 (30 L m-2 every week during 6 months up to present day). The results showed a clear decrease of aggregate stability during the period we used the second dose (D50) independent of the type of water used. That dose of irrigation and frequency produced strong wetting and drying cycles (WD) in the soil, and this is suspected to be the main factor responsible for the results. When we changed the dose of irrigation to D30, reducing the quantity per event and increasing the frequency, the soil aggregate stability started to improve. This dose avoids strong drying periods between irrigation events and the aggregate stability is confirmed to be slowly

  18. Genetic differences in Native Americans and tacrolimus dosing after kidney transplantation.

    PubMed

    Chakkera, H A; Chang, Y-H; Bodner, J K; Behmen, S; Heilman, R L; Reddy, K S; Mulligan, D C; Moss, A A; Khamash, H; Katariya, N; Hewitt, W R; Pitta, T L; Frassetto, L A

    2013-01-01

    Tacrolimus pharmacokinetics vary due to single nucleotide polymorphisms (SNPs) in metabolizing enzymes and membrane transporters that alter drug elimination. Clinically we observed that Native Americans require lower dosages of tacrolimus to attain trough levels similar to Caucasians. We previously demonstrated that Native Americans have decreased oral clearance of tacrolimus, suggesting that Native Americans may have more variant SNPs and, therefore, altered tacrolimus pharmacokinetic parameters. We conducted 12-hour pharmacokinetic studies on 24 adult Native American kidney transplant recipients on stable doses of tacrolimus for at least 1 month posttransplantation. Twenty-four Caucasian kidney transplant recipients were compared as controls. SNPs encoding the genes for the enzymes (CYP3A4, CYP3A5) and transporters (ABCB1, BCRP, and MRP1) were typed using TaqMan. The mean daily tacrolimus dose in the Native Americans was 0.03 ± 0.02 compared with the Caucasians 0.5 ± 0.3 (mg/kg/d; P = .002), with no significant differences in trough levels, (6.7 ± 3.1 vs 7.4 ± 2.1 ng/dL; P = .4). Many Native Americans, but not Caucasians, demonstrated the 3/*3 - C3435T CC and the *3/*3 -G2677T GG genotype combination previously associated with low tacrolimus dosing. Native Americans required significantly lower tacrolimus doses than Caucasians to achieve similar tacrolimus trough levels, in part due to lower tacrolimus clearance from decreased drug metabolism and excretion. PMID:23375287

  19. Effective Dose of Radon 222 Bottled Water in Different Age Groups Humans: Bandar Abbas City, Iran.

    PubMed

    Fakhri, Yadolah; Mahvi, Amir Hossein; Langarizadeh, Ghazaleh; Zandsalimi, Yahya; Amirhajeloo, Leila Rasouli; Kargosha, Morteza; Moradi, Mahboobeh; Moradi, Bigard; Mirzaei, Maryam

    2016-01-01

    Radon 222 is a natural radioactive element with a half-life of 3.8 days. It is odorless and colorless as well as water-soluble. Consuming waters which contain high concentration of 222Rn would increase the effective dose received by different age groups. It would also be followed by an increased prevalence of cancer. In this research, 72 samples of the most commonly used bottled water in Bandar Abbas were collected in 3 consecutive months, May, June and July of 2013. Concentration 222Rn of was measured by radon-meter model RTM166-2. The effective dose received by the 4 age groups, male and female adults as well as children and infants was estimated using the equation proposed by UNSCEAR. The results revealed that the mean and range concentration of 222Rn in bottled waters were 641±9 Bq/m3 and 0-901 Bq/m3, respectively. The mean concentration of 222Rn in the well-known Marks followed this Zam Zam>Bishe>Koohrng>Dassani>Christal>Polour>Damavand>Sivan. Infants were observed to receive a higher effective dose than children. The highest and lowest effective dose received was found to belong to male adults and children, respectively. PMID:26383192

  20. Effective Dose of Radon 222 Bottled Water in Different Age Groups Humans: Bandar Abbas City, Iran.

    PubMed

    Fakhri, Yadolah; Mahvi, Amir Hossein; Langarizadeh, Ghazaleh; Zandsalimi, Yahya; Amirhajeloo, Leila Rasouli; Kargosha, Morteza; Moradi, Mahboobeh; Moradi, Bigard; Mirzaei, Maryam

    2015-06-04

    Radon 222 is a natural radioactive element with a half-life of 3.8 days. It is odorless and colorless as well as water-soluble. Consuming waters which contain high concentration of 222Rn would increase the effective dose received by different age groups. It would also be followed by an increased prevalence of cancer. In this research, 72 samples of the most commonly used bottled water in Bandar Abbas were collected in 3 consecutive months, May, June and July of 2013. Concentration 222Rn of was measured by radon-meter model RTM166-2. The effective dose received by the 4 age groups, male and female adults as well as children and infants was estimated using the equation proposed by UNSCEAR. The results revealed that the mean and range concentration of 222Rn in bottled waters were 641±9 Bq/m3 and 0-901 Bq/m3, respectively. The mean concentration of 222Rn in the well-known Marks followed this Zam Zam>Bishe>Koohrng>Dassani>Christal>Polour>Damavand>Sivan. Infants were observed to receive a higher effective dose than children. The highest and lowest effective dose received was found to belong to male adults and children, respectively.

  1. Effective Dose of Radon 222 Bottled Water in Different Age Groups Humans: Bandar Abbas City, Iran

    PubMed Central

    Fakhri, Yadolah; Mahvi, Amir Hossein; Langarizadeh, Ghazaleh; Zandsalimi, Yahya; Amirhajeloo, Leila Rasouli; Kargosha, Morteza; Moradi, Mahboobeh; Moradi, Bigard; Mirzaei, Maryam

    2016-01-01

    Radon 222 is a natural radioactive element with a half-life of 3.8 days. It is odorless and colorless as well as water-soluble. Consuming waters which contain high concentration of 222Rn would increase the effective dose received by different age groups. It would also be followed by an increased prevalence of cancer. In this research, 72 samples of the most commonly used bottled water in Bandar Abbas were collected in 3 consecutive months, May, June and July of 2013. Concentration 222Rn of was measured by radon-meter model RTM166-2. The effective dose received by the 4 age groups, male and female adults as well as children and infants was estimated using the equation proposed by UNSCEAR. The results revealed that the mean and range concentration of 222Rn in bottled waters were 641±9 Bq/m3 and 0-901 Bq/m3, respectively. The mean concentration of 222Rn in the well-known Marks followed this Zam Zam>Bishe>Koohrng>Dassani>Christal>Polour>Damavand>Sivan. Infants were observed to receive a higher effective dose than children. The highest and lowest effective dose received was found to belong to male adults and children, respectively. PMID:26383192

  2. Doses delivered to normal brain under different treatment protocols at Brookhaven National Laboratory

    SciTech Connect

    Capala, J.; Coderre, J.A.; Liu, H.B.

    1996-12-31

    As of October 31, 1996, 23 glioblastoma multiforme patients underwent BNCT under several treatment protocols at the Brookhaven Medical Research Reactor. For treatment planning and dosimetry purposes, these protocols may be divided into four groups. The first group comprises protocols that used an 8-cm collimator and allowed a peak normal brain dose of 10.5 Gy-Eq to avolume of 1 cm{sup 3} were the thermal neutron flux was maximal (even if it happened to be in the tumor volume). The second group differs from the first in that it allowed a peak normal brain dose of 12.6 Gy-Eq. The protocols of the third and fourth groups allowed the prescribed peak normal brain dose of 12.6 Gy-Eq to be outside of the tumor volume, used a 12-cm collimator and, respectively, uni- or bilateral irradiations. We describe the treatment planning procedures and report the doses delivered to various structures of the brain.

  3. Effect of different doses of un-fractionated green and black tea extracts on thyroid physiology.

    PubMed

    Chandra, Amar K; De, Neela; Choudhury, Shyamosree Roy

    2011-08-01

    Tea is a rich source of polyphenolic flavonoids including catechins, which are thought to contribute to the health benefits of it. Flavonoids have been reported to have antithyroid and goitrogenic effect. The purpose of this study was to evaluate whether high doses of green and black tea have a harmful effect on thyroid physiology. Un-fractionated green and black tea extracts were administered orally to male rats for 30 days at doses of 1.25 g%, 2.5 g% and 5.0 g%. The results showed that green tea extract at 2.5 g% and 5.0 g% doses and black tea extract only at 5.0 g% dose have the potential to alter the thyroid gland physiology and architecture, that is, enlargement of thyroid gland as well as hypertrophy and/or hyperplasia of the thyroid follicles and inhibition of the activity of thyroid peroxidase and 5(')-deiodinase I with elevated thyroidal Na+, K+-ATPase activity along with significant decrease in serum T3 and T4, and a parallel increase in serum thyroid stimulating hormone (TSH). This study concludes that goitrogenic/antithyroidal potential of un-fractionated green tea extract is much more than black tea extract because of the differences in catechin contents in the tea extracts.

  4. Effects of different doses of caffeine on anaerobic exercise in boys.

    PubMed

    Turley, Ken; Eusse, Paola A; Thomas, Myles M; Townsend, Jeremy R; Morton, Aaron B

    2015-02-01

    This study investigated effects of low (1 mg·kg-1), moderate (3 mg·kg-1) and high (5 mg·kg-1) doses of caffeine on anaerobic performance in boys. Twenty-six 8- to 10-year-old boys participated in a double-blind, crossover, counter-balanced study. Boys received in random order a placebo (PL) or anhydrous caffeine: 1 (CAF-1), 3 (CAF-3), or 5 (CAF-5) mg caffeine·kg-1 body mass in cherry flavored Sprite. Sixty minutes following consumption boys performed a static handgrip test and then a 30-s Wingate test. Maximal grip strength (21.5 ± 4.9 & 21.6 ± 4.7 vs. 20.4 ± 4.0 kg) was significantly higher in CAF-5 & CAF-3 vs PL, respectively. Absolute and relative peak power (287 ± 72 vs 281 ± 69 W & 8.0 ± 0.9 vs 7.8 ± 1.0 W·kg-1) were significantly higher in CAF-3 vs PL, respectively. Mean power (153 ± 48 vs 146 ± 43 W) was significantly higher in CAF-5 vs PL, respectively. Peak Wingate HR was significantly higher (189 ± 8 vs 185 ± 9 beats·min-1) in CAF-5 vs PL, respectively. These findings suggest that in boys CAF-1 did not affect performance. During the Wingate test CAF-3 resulted in higher peak power while CAF-5 increased mean power. The significant increase in peak HR following the Wingate test is likely related to greater mean power generated during CAF-5. PMID:25051124

  5. Effects of different doses of caffeine on anaerobic exercise in boys.

    PubMed

    Turley, Ken; Eusse, Paola A; Thomas, Myles M; Townsend, Jeremy R; Morton, Aaron B

    2015-02-01

    This study investigated effects of low (1 mg·kg-1), moderate (3 mg·kg-1) and high (5 mg·kg-1) doses of caffeine on anaerobic performance in boys. Twenty-six 8- to 10-year-old boys participated in a double-blind, crossover, counter-balanced study. Boys received in random order a placebo (PL) or anhydrous caffeine: 1 (CAF-1), 3 (CAF-3), or 5 (CAF-5) mg caffeine·kg-1 body mass in cherry flavored Sprite. Sixty minutes following consumption boys performed a static handgrip test and then a 30-s Wingate test. Maximal grip strength (21.5 ± 4.9 & 21.6 ± 4.7 vs. 20.4 ± 4.0 kg) was significantly higher in CAF-5 & CAF-3 vs PL, respectively. Absolute and relative peak power (287 ± 72 vs 281 ± 69 W & 8.0 ± 0.9 vs 7.8 ± 1.0 W·kg-1) were significantly higher in CAF-3 vs PL, respectively. Mean power (153 ± 48 vs 146 ± 43 W) was significantly higher in CAF-5 vs PL, respectively. Peak Wingate HR was significantly higher (189 ± 8 vs 185 ± 9 beats·min-1) in CAF-5 vs PL, respectively. These findings suggest that in boys CAF-1 did not affect performance. During the Wingate test CAF-3 resulted in higher peak power while CAF-5 increased mean power. The significant increase in peak HR following the Wingate test is likely related to greater mean power generated during CAF-5.

  6. Effect of different doses of Manuka honey in experimentally induced inflammatory bowel disease in rats.

    PubMed

    Prakash, A; Medhi, B; Avti, P K; Saikia, U N; Pandhi, P; Khanduja, K L

    2008-11-01

    To evaluate the effect of different doses of Manuka honey in experimentally induced inflammatory bowel disease in rats. Adult Wistar rats of either sex were used (n = 30). Colitis was induced by a single intracolonic administration of TNBS dissolved in 35% ethanol. The rats (n = 30) were divided into five groups (n = 6) and were treated with vehicle (ethanol), TNBS, Manuka honey (5 g/kg, p.o.), Manuka honey (10 g/kg, p.o.) or sulfasalazine (360 mg/kg, p.o.) body weight for 14 days. After completion of treatment, the animals were killed and the following parameters were assessed: morphological score, histological score and different antioxidant parameters.Manuka honey at different doses provided protection against TNBS-induced colonic damage. There was significant protection with Manuka honey 5 g/kg as well as with 10 g/kg body weight compared with the control (p < 0.001). All the treated groups showed reduced colonic inflammation and all the biochemical parameters were significantly reduced compared with the control in the Manuka honey treated groups (p < 0.001). Manuka honey at different doses restored lipid peroxidation as well as improved antioxidant parameters. Morphological and histological scores were significantly reduced in the low dose Manuka honey treated group (p < 0.001). In the inflammatory model of colitis, oral administration of Manuka honey 5 g/kg and Manuka honey 10 g/kg body weight significantly reduced the colonic inflammation. The present study indicates that Manuka honey is efficacious in the TNBS-induced rat colitis model, but these results require further confirmation in human studies.

  7. Influence of difference in cross-sectional dose profile in a CTDI phantom on X-ray CT dose estimation: a Monte Carlo study.

    PubMed

    Haba, Tomonobu; Koyama, Shuji; Ida, Yoshihiro

    2014-01-01

    The longitudinal dose profile in a computed tomography dose index (CTDI) phantom had been studied by many researchers. The cross-sectional dose profile in the CTDI phantom, however, has not been studied. It is also important to understand the cross-sectional dose profile in the CTDI phantom for dose estimation in X-ray CT. In this study, the cross-sectional dose profile in the CTDI phantom was calculated by use of a Monte Carlo (MC) simulation method. A helical or a 320-detector-row cone-beam X-ray CT scanner was simulated. The cross-sectional dose profile in the CTDI phantom from surface to surface through the center point was calculated by MC simulation. The shape of the calculation region was a cylinder of 1-mm-diameter. The length of the cylinder was 23, 100, or 300 mm to represent various CT ionization chamber lengths. Detailed analyses of the energy depositions demonstrated that the cross-sectional dose profile was different in measurement methods and phantom sizes. In this study, we also focused on the validation of the weighting factor used in weighted CTDI (CTDI w ). As it stands now, the weighting factor used in CTDI w is (1/3, 2/3) for the (central, peripheral) axes. Our results showed that an equal weighting factor, which is (1/2, 1/2) for the (central, peripheral) axes, is more suitable to estimate the average cross-sectional dose when X-ray CT dose estimation is performed.

  8. Growth alteration and leaf biochemical responses in Phaseolus vulgaris exposed to different doses of ionising radiation.

    PubMed

    Arena, C; De Micco, V; De Maio, A

    2014-01-01

    Ionising radiation may have different effects on plant metabolism, growth and reproduction, depending on radiation dose, plant species, developmental stage and physiological traits. In this study, exposure of dwarf bean plants to different doses of X-rays (0.3, 10, 50, 100 Gy) was investigated with a multidisciplinary approach consisting of morphological, ecophysiological and biochemical analysis. Both mature and young leaves still growing during the X-rays exposure were compared with non-irradiated control leaves. In particular, leaf expansion, leaf anatomy and functional traits, as well as photosynthetic pigment content and Rubisco expression were analysed. Moreover, the activity of poly(ADP-ribose) polymerase (PARP) was also measured as an indicator of radiation-induced DNA damage. Our data showed that leaf growth is affected by high levels of radiation and demonstrate that mature leaves are more radio-resistant than young leaves, which experience severe dose-dependent changes in leaf functional traits. In particular, young leaves exhibited a reduction of area and an increase in specific mass and dry matter content, as well as a decline in Rubisco activity. Moreover, they showed elevated PARP activity and an increase in phenolic compounds in wall cells if compared with mature leaves. Both of these strategies have been interpreted as a way to help developing leaves withstand irradiation.

  9. Analysis of the space radiation doses obtained simultaneously at two different locations outside the ISS

    NASA Astrophysics Data System (ADS)

    Dachev, T. P.

    2013-12-01

    Space weather and related ionizing radiation has been recognized as one of the main health concerns for the International Space Station (ISS) crew. The estimation of the radiation effect on humans outside the ISS requires at first order accurate knowledge of their accumulated absorbed dose rates, which depend on the global space radiation distribution, solar cycle and local variations generated by the 3D mass distribution surrounding the ISS. The R3DE (Radiation Risks Radiometer-Dosimeter for the EXPOSE-E platform) on the European Technological Exposure Facility (EuTEF) worked successfully outside of the European Columbus module between February 2008 and September 2009. A very similar instrument named R3DR for the EXPOSE-R platform worked outside the Russian Zvezda module of the ISS between March 2009 and August 2010. Both are Liulin-type detectors, Bulgarian-built miniature spectrometer-dosimeters. The acquired approximately 5 million deposited energy spectra from which the flux and absorbed dose rate were calculated with 10 s resolution behind less than 0.41 g cm-2 shielding. This paper analyses the spectra collected in 2009 by the R3DE/R instruments and the long-term variations in the different radiation environments of Galactic Cosmic Rays (GCR), inner radiation belt trapped protons in the region of the South Atlantic Anomaly (SAA) and relativistic electrons from the Outer Radiation Belt (ORB). The R3DE instrument, heavily shielded by the surrounding structures, measured smaller primary fluxes and dose rates from energetic protons from the SAA and relativistic electrons from the ORB but higher values from GCRs because of the contribution from secondary particles. The main conclusion from this investigation is that the dose rates from different radiation sources around the International Space Station (ISS) have a large special and temporal dynamic range. The collected data can be interpreted as possible doses obtained by the cosmonauts and astronauts during

  10. Population pharmacokinetics of arbekacin in different infectious disease settings and evaluation of dosing regimens.

    PubMed

    Hagihara, Mao; Kato, Hideo; Hamada, Yukihiro; Hirai, Jun; Sakanashi, Daisuke; Suematsu, Hiroyuki; Nishiyama, Naoya; Koizumi, Yusuke; Yamagishi, Yuka; Matsuura, Katsuhiko; Mikamo, Hiroshige

    2016-07-01

    The efficacy of arbekacin in patients with MRSA infections is influenced by the peak concentration (Cpeak)/MIC ratio (≧8). A daily arbekacin dose of 4-6 mg/kg is primarily used for the treatment of MRSA infection. However, clinical pharmacokinetic studies of arbekacin that evaluate changes in patients with different infectious diseases have been limited. This study was to evaluate the pharmacokinetics of arbekacin in different infectious diseases and to evaluate its dosing regimens. This work describes a single-centre, retrospective study. The pharmacokinetic parameters of arbekacin were calculated from individual serum-concentration data using WinNonlin ver. 6.3. A total of 331 serum samples were obtained from 170 patients. Our drug concentration-time data were well described by a two-compartment open model. The final model showed that drug clearance was related to creatinine clearance and that the total distribution volume (Vd) was related to actual body weight and the presence of bacteremia. The individual Vd in bacteremia patients was significantly higher than those of other patients (bacteremia: 29.7 ± 0.5 L, pneumonia: 20.8 ± 0.4 L, other infections: 21.4 ± 0.4 L; p < 0.05). Additionally, Monte Carlo simulation showed that target (Cpeak/MIC ≧ 8) attainment was only 10.1%, even at a dose of 6 mg/kg, especially for MRSA bacteremia patients with an arbekacin MIC = 2 μg/mL. In conclusion, our study revealed that the Vd may be higher in bacteremia patients than in patients with other infectious diseases. Therefore, an increase in the daily dose of arbekacin should be considered for bacteremia patients. PMID:27260679

  11. The absolute path command

    2012-05-11

    The ap command traveres all symlinks in a given file, directory, or executable name to identify the final absolute path. It can print just the final path, each intermediate link along with the symlink chan, and the permissions and ownership of each directory component in the final path. It has functionality similar to "which", except that it shows the final path instead of the first path. It is also similar to "pwd", but it canmore » provide the absolute path to a relative directory from the current working directory.« less

  12. The absolute path command

    SciTech Connect

    Moody, A.

    2012-05-11

    The ap command traveres all symlinks in a given file, directory, or executable name to identify the final absolute path. It can print just the final path, each intermediate link along with the symlink chan, and the permissions and ownership of each directory component in the final path. It has functionality similar to "which", except that it shows the final path instead of the first path. It is also similar to "pwd", but it can provide the absolute path to a relative directory from the current working directory.

  13. Measurement of eye lens dose for Varian On-Board Imaging with different cone-beam computed tomography acquisition techniques.

    PubMed

    Deshpande, Sudesh; Dhote, Deepak; Thakur, Kalpna; Pawar, Amol; Kumar, Rajesh; Kumar, Munish; Kulkarni, M S; Sharma, S D; Kannan, V

    2016-01-01

    The objective of this work was to measure patient eye lens dose for different cone-beam computed tomography (CBCT) acquisition protocols of Varian's On-Board Imaging (OBI) system using optically stimulated luminescence dosimeter (OSLD) and to study the variation in eye lens dose with patient geometry and distance of isocenter to the eye lens. During the experimental measurements, OSLD was placed on the patient between the eyebrows of both eyes in line of nose during CBCT image acquisition to measure eye lens doses. The eye lens dose measurements were carried out for three different cone-beam acquisition protocols (standard dose head, low-dose head [LDH], and high-quality head [HQH]) of Varian OBI. Measured doses were correlated with patient geometry and distance between isocenter and eye lens. Measured eye lens doses for standard head and HQH protocols were in the range of 1.8-3.2 mGy and 4.5-9.9 mGy, respectively. However, the measured eye lens dose for the LDH protocol was in the range of 0.3-0.7 mGy. The measured data indicate that eye lens dose to patient depends on the selected imaging protocol. It was also observed that eye lens dose does not depend on patient geometry but strongly depends on distance between eye lens and treatment field isocenter. However, undoubted advantages of imaging system should not be counterbalanced by inappropriate selection of imaging protocol, especially for very intense imaging protocol. PMID:27651564

  14. Effects of different SRT on anaerobic digestion of MSW dosed with various MSWI ashes.

    PubMed

    Lo, H M; Chiu, H Y; Lo, S W; Lo, F C

    2012-12-01

    This study investigated different solid retention time (SRT) on municipal solid waste (MSW) anaerobic digestion with various MSW incinerator fly ash (FA) and bottom ash (BA) addition. Results showed that biogas production rates (BPRs, ≈ 200 to ≈ 400 mL/gVS) with organic loading rate of ≈ 0.053 gVS/gVS(reactor) (Day 1-435, SRT 20 days, SRT20) at FA 1g/d (FA1), BA 12 g/d (BA12) and BA 24 g/d (BA24) dosed bioreactors increased after adaptation. BPRs with SRT10 and SRT5 decreased while BPRs with SRT40 showed to increase compared to initial BPRs (≈ 200 mL/gVS) with SRT20. SRT5 operation reduced the BPRs (≈ 10 - ≈ 90 mL/gVS) significantly and only BA12 and BA24 dosed bioreactors could recover the BPRs (≈ 100 - ≈ 200 mL/gVS) after SRT20 operation (Day 613-617) compared to FA1 and FA3 and control. Released levels of Co, Mo and W at BA12 and BA24 dosed bioreactors showed most potential to improve MSW anaerobic digestion. PMID:23026339

  15. Different doses of partial liver irradiation promotes hepatic regeneration in rat.

    PubMed

    Liu, Ying; Shi, Changzheng; Cui, Meng; Yang, Zhenhua; Gan, Danhui; Wang, Yiming

    2015-01-01

    The aim of this study is to investigate whether partial liver irradiation promotes hepatic regeneration in rat. Left-half liver of rat was irradiated to 10 Gy, and the Right-half to 0, 5, 10 and 15 Gy, respectively. Then, serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) levels were evaluated on 0 day, 15-day, 30-day, 45-day and 60-day after liver irradiation. Next, the serum HGF, NF-κB and TGF-β1 levels were also analyzed on 60-day after liver irradiation. Lastly, the cyclinD1 protein expression was appraised by western blots on 60-day after liver irradiation. ALT, AST and ALP levels were reduced compared with that of controls. The serum HGF, NF-κB and TGF-β1 levels, and the cyclinD1 protein expression in liver irradiation group were increased compared with that of controls group. However, hepatic regeneration of higher dose-irradiated cirrhotic liver was triggered a more enhanced regeneration, compared with that of higher doses group. In summary, these results suggest that different doses of partial liver irradiation promotes hepatic regeneration in rat.

  16. Dose response of CaF2:Tm to charged particles of different LET.

    PubMed

    Moyers, M F; Nelson, G A

    2009-08-01

    Thermoluminescent dosimeters are well established for performing calibrations in radiotherapy and for monitoring dose to personnel exposed to low linear energy transfer (LET) ionizing radiation. Patients undergoing light ion therapy and astronauts engaged in space flight are, however, exposed to radiation fields consisting of a mix of low- and high-LET charged particles. In this study, glow curves from CaF2:Tm chips were examined after exposure to various electron and ion beams. The annealing and readout procedures for these chips were optimized for these beams. After a 10 min prereadout annealing at 100 degrees C, the optimized glow curve samples the light output between 95 and 335 degrees C with a heating rate of 2 degrees C/s. The ratio of the integral of the glow curve under peaks 4-6 to the integral under peak 3 was approximately 0.9 for electrons, 1.0 for entrance protons, 1.6 for peak protons, and 2.2 for entrance carbon, silicon, and iron ions. The integral light output per unit dose in water for the iron exposures was about half as much as for the electron exposures. The peak-area-ratio can be used to determine a dose response factor for different LET radiations. PMID:19746804

  17. Comparison of different approaches of estimating effective dose from reported exposure data in 3D imaging with interventional fluoroscopy systems

    NASA Astrophysics Data System (ADS)

    Svalkvist, Angelica; Hansson, Jonny; Bâth, Magnus

    2014-03-01

    Three-dimensional (3D) imaging with interventional fluoroscopy systems is today a common examination. The examination includes acquisition of two-dimensional projection images, used to reconstruct section images of the patient. The aim of the present study was to investigate the difference in resulting effective dose obtained using different levels of complexity in calculations of effective doses from these examinations. In the study the Siemens Artis Zeego interventional fluoroscopy system (Siemens Medical Solutions, Erlangen, Germany) was used. Images of anthropomorphic chest and pelvis phantoms were acquired. The exposure values obtained were used to calculate the resulting effective doses from the examinations, using the computer software PCXMC (STUK, Helsinki, Finland). The dose calculations were performed using three different methods: 1. using individual exposure values for each projection image, 2. using the mean tube voltage and the total DAP value, evenly distributed over the projection images, and 3. using the mean kV and the total DAP value, evenly distributed over smaller selection of projection images. The results revealed that the difference in resulting effective dose between the first two methods was smaller than 5%. When only a selection of projection images were used in the dose calculations the difference increased to over 10%. Given the uncertainties associated with the effective dose concept, the results indicate that dose calculations based on average exposure values distributed over a smaller selection of projection angles can provide reasonably accurate estimations of the radiation doses from 3D imaging using interventional fluoroscopy systems.

  18. Serious complications in experiments in which UV doses are effected by using different lamp heights.

    PubMed

    Flint, Stephan D; Ryel, Ronald J; Hudelson, Timothy J; Caldwell, Martyn M

    2009-10-01

    Many experiments examining plant responses to enhanced ultraviolet-B radiation (280-315nm) simply compare an enhanced UV-B treatment with ambient UV-B (or no UV-B radiation in most greenhouse and controlled-environment studies). Some more detailed experiments utilize multiple levels of UV-B radiation. A number of different techniques have been used to adjust the UV dose. One common technique is to place racks of fluorescent UV-emitting lamps at different heights above the plant canopy. However, the lamps and associated support structure cast shadows on the plant bed below. We calculated one example of the sequence of shade intervals for two common heights of lamp racks and show the patterns and duration of shade which the plants receive is distributed differently over the course of the day for different heights of the lamp racks. We also conducted a greenhouse experiment with plants (canola, sunflower and maize) grown under unenergized lamp racks suspended at the same two heights above the canopy. Growth characteristics differed in unpredictable ways between plants grown under the two heights of lamp racks. These differences could enhance or obscure potential UV-B effects. Also, differences in leaf mass per unit foliage area, which were observed in this experiment, could contribute to differences in plant UV-B sensitivity. We recommend the use of other techniques for achieving multiple doses of UV-B radiation. These range from simple and inexpensive approaches (e.g., wrapping individual fluorescent tubes in layers of a neutral-density filter such as cheese cloth) to more technical and expensive alternatives (e.g., electronically modulated lamp control systems). These choices should be determined according to the goals of the particular experiment. PMID:19709898

  19. Organ doses, effective doses, and risk indices in adult CT: Comparison of four types of reference phantoms across different examination protocols

    SciTech Connect

    Zhang Yakun; Li Xiang; Paul Segars, W.; Samei, Ehsan

    2012-06-15

    Purpose: Radiation exposure from computed tomography (CT) to the public has increased the concern among radiation protection professionals. Being able to accurately assess the radiation dose patients receive during CT procedures is a crucial step in the management of CT dose. Currently, various computational anthropomorphic phantoms are used to assess radiation dose by different research groups. It is desirable to better understand how the dose results are affected by different choices of phantoms. In this study, the authors assessed the uncertainties in CT dose and risk estimation associated with different types of computational phantoms for a selected group of representative CT protocols. Methods: Routinely used CT examinations were categorized into ten body and three neurological examination categories. Organ doses, effective doses, risk indices, and conversion coefficients to effective dose and risk index (k and q factors, respectively) were estimated for these examinations for a clinical CT system (LightSpeed VCT, GE Healthcare). Four methods were used, each employing a different type of reference phantoms. The first and second methods employed a Monte Carlo program previously developed and validated in our laboratory. In the first method, the reference male and female extended cardiac-torso (XCAT) phantoms were used, which were initially created from the Visible Human data and later adjusted to match organ masses defined in ICRP publication 89. In the second method, the reference male and female phantoms described in ICRP publication 110 were used, which were initially developed from tomographic data of two patients and later modified to match ICRP 89 organ masses. The third method employed a commercial dosimetry spreadsheet (ImPACT group, London, England) with its own hermaphrodite stylized phantom. In the fourth method, another widely used dosimetry spreadsheet (CT-Expo, Medizinische Hochschule, Hannover, Germany) was employed together with its associated

  20. Modification of spectral ultraviolet doses by different types of overcast cloudiness and atmospheric aerosol.

    PubMed

    Aun, Margit; Eerme, Kalju; Ansko, Ilmar; Veismann, Uno; Lätt, Silver

    2011-01-01

    Wavelength-dependent attenuation of ground-level ultraviolet (UV) dose by different cloud and aerosol situations at the Tartu Observatory site (58°15' N, 26°28' E, 70 m a.s.l) is under scrutiny. The spectra at wavelengths ranging below 400 nm have been recorded by the simple Avantes, Inc. array spectrometer AvaSpec-256 in 2004-2009. The spectral information was supported by the conventional broadband solar irradiance and by the necessary meteorological data. The average cloud modification factor (CMF) on overcast days from May to August has been quite low, 0.36 in UVA and 0.35 in UVB. In the UVA range, the reduction of the daily dose with increasing noon solar zenith angle (SZA) from 35-50° to 65-80° in overcast days has been about 20% more than in clear days, while in the UVB range it was 45% larger. No clear difference in the influence of SZA on CMF between low level (St, Ns) and medium level (As, Ac) overcast cloudiness has been found. The aerosol attenuation during large aerosol optical depth (AOD) episode has been comparable with that of medium level clouds with the wavelength dependency in the UVA range different from that of clouds.

  1. Thermal stability of PVC formulations gamma irradiated at different dose rates

    NASA Astrophysics Data System (ADS)

    Castañeda-Facio, A.; Benavides, R.; Martínez-Pardo, M. E.

    2014-04-01

    Polyvinyl chloride (PVC) formulated with two different stabilizer systems (Ca/Zn stearates and dibasic lead phthalate) irradiated at 75 kGy at two different dose rates were studied in order to evaluate their effect in thermal stability. Samples were degraded in a TGA instrument at different heating rates and the activation energy (Ea) to dehydrochlorination was calculated using the Arrhenius method in accordance with ASTM E 1641-07. TGA evaluations show that temperature for HCl evolution is higher when increasing heating rate, as well as higher resistance to degradation, for irradiated lead formulations; however, after activation energies calculation the irradiated Ca/Zn formulations are more stable. The controversial results are due to the low initial stability of lead additives in PVC.

  2. Development of immunoglobulin and antibody-synthesizing cells after immunization with different doses of antigen.

    PubMed Central

    Antoine, J C; Petit, C; Avrameas, S

    1976-01-01

    The kinetics of development of antibody-synthesizing cells and of cells synthesizing immunoglobulins without detectable antibody function were studied in rats immunized with different doses (0-1, 1, 10, 100 mg) of horse radish peroxidase, bovine serum albumin, human serum albumin, hen ovalbumin, or human IgG, which had been deaggregated or heat-aggregated. Each antigen was injected once or twice as a solution in saline. Antibody and immunoglobulin-producing cells were detected in draining lymph nodes by immunohistochemical staining. In the primary response a few antibody-synthesizing cells were found whatever the dose injected. No increase or some increase was found with the amount of antigen injected, according to the protein used, but with all doses of antigen injected, the population of cells remained small, except with human IgG where a relatively high number of positive cells was detected even after injection of 1 mg of antigen. In the secondary response a few antibody-forming cells were also detected with the lower doses of antigen, but this population increased after boosting with 100 mg of antigen. With human IgG a greater number of positive cells was induced withall the doses tested. A correlation between the number of cells synthesizing immunoglobulins without antibody function and the amount of antigen injected was observed in the primary and secondary responses. The relative size of these two populations varied with the stage of immunity of the animals. In the primary response, the population of cells synthesizing immunoglobulins without antibody function was larger than the population of antibody-forming cells. The same was true in the secondary response, but if after a booster injection the level of antibody-synthesizing cells exceeded that reached in the primary response, the increase of cells synthesizing Ig without antibody function was smaller than the increase in antibody-forming cells. In general the more immunogenic an antigen was, the smaller

  3. Mutation induction by different dose rates of gamma rays in radiation-sensitive mutants of mouse leukemia cells

    SciTech Connect

    Furuno-Fukushi, I.; Matsudaira, H. )

    1989-11-01

    Induction of cell killing and mutation to 6-thioguanine resistance was examined in a radiation-sensitive mutant strain LX830 of mouse leukemia cells following gamma irradiation at dose rates of 30 Gy/h (acute), 20 cGy/h (low dose rate), and 6.2 mGy/h (very low dose rate). LX830 cells were hypersensitive to killing by acute gamma rays. A slight but significant increase was observed in cell survival with decreasing dose rate down to 6.2 mGy/h, where the survival leveled off above certain total doses. The cells were also hypersensitive to mutation induction compared to the wild type. The mutation frequency increased linearly with increasing dose for all dose rates. No significant difference was observed in the frequency of induced mutations versus total dose at the three different dose rates so that the mutation frequency in LX830 cells at 6.2 mGy/h was not significantly different from that for moderate or acute irradiation.

  4. SU-E-T-422: Correlation Between 2D Passing Rates and 3D Dose Differences for Pretreatment VMAT QA

    SciTech Connect

    Jin, X; Xie, C

    2014-06-01

    Purpose: Volumetric modulated arc therapy (VMAT) quality assurance (QA) is typically using QA methods and action levels taken from fixedbeam intensity-modulated radiotherapy (IMRT) QA methods. However, recent studies demonstrated that there is no correlation between the percent gamma passing rate (%GP) and the magnitude of dose discrepancy between the planned dose and the actual delivered dose for IMRT. The purpose of this study is to investigate whether %GP is correlated with clinical dosimetric difference for VMAT. Methods: Twenty nasopharyngeal cancer (NPC) patients treated with dual-arc simultaneous integrated boost VMAT and 20 esophageal cancer patients treated with one-arc VMAT were enrolled in this study. Pretreatment VMAT QA was performed by a 3D diode array ArcCheck. Acceptance criteria of 2%/2mm, 3%/3mm, and 4%/4mm were applied for 2D %GP. Dose values below 10% of the per-measured normalization maximum dose were ignored.Mean DVH values obtained from 3DVH software and TPS were calculated and percentage dose differences were calculated. Statistical correlation between %GP and percent dose difference was studied by using Pearson correlation. Results: The %GP for criteria 2%/2mm, 3%/3mm, and 4%/4mm were 82.33±4.45, 93.47±2.31, 97.13±2.41, respectively. Dose differences calculated from 3DVH and TPS for beam isocenter, mean dose of PTV, maximum dose of PTV, D2 of PTV and D98 of PTV were -1.04±3.24, -0.74±1.71, 2.92±3.62, 0.89±3.29, -1.46±1.97, respectively. No correction were found between %GP and dose differences. Conclusion: There are weak correlations between the 2D %GP and dose differences calculated from 3DVH. The %GP acceptance criteria of 3%/3mm usually applied for pretreatment QA of IMRT and VMAT is not indicating strong clinical correlation with 3D dose difference. 3D dose reconstructions on patient anatomy may be necessary for physicist to predict the accuracy of delivered dose for VMAT QA.

  5. A 3-lever discrimination procedure reveals differences in the subjective effects of low and high doses of MDMA.

    PubMed

    Harper, David N; Langen, Anna-Lena; Schenk, Susan

    2014-01-01

    Drug discrimination studies have suggested that the subjective effects of low doses of (±)3,4-methylenedioxymethamphetamine (MDMA) are readily differentiated from those of d-amphetamine (AMPH) and that the discriminative stimulus properties are mediated by serotonergic and dopaminergic mechanisms, respectively. Previous studies, however, have primarily examined responses to doses that do not produce substantial increases in extracellular dopamine. The present study determined whether doses of MDMA that produce increases in synaptic dopamine would also produce subjective effects that were more like AMPH and were sensitive to pharmacological manipulation of D1-like receptors. A three-lever drug discrimination paradigm was used. Rats were trained to respond on different levers following saline, AMPH (0.5mg/kg, IP) or MDMA (1.5mg/kg, IP) injections. Generalization curves were generated for a range of different doses of both drugs and the effect of the D1-like antagonist, SCH23390 on the discriminative stimulus effects of different doses of MDMA was determined. Rats accurately discriminated MDMA, AMPH and saline. Low doses of MDMA produced almost exclusive responding on the MDMA lever but at doses of 3.0mg/kg MDMA or higher, responding shifted to the AMPH lever. The AMPH response produced by higher doses of MDMA was attenuated by pretreatment with SCH23390. The data suggest that low doses and higher doses of MDMA produce distinct discriminative stimuli. The shift to AMPH-like responding following administration of higher doses of MDMA, and the decrease in this response following administration of SCH23390 suggests a dopaminergic component to the subjective experience of MDMA at higher doses.

  6. Circulating inflammatory miRNA signature in response to different doses of aerobic exercise.

    PubMed

    de Gonzalo-Calvo, David; Dávalos, Alberto; Montero, Ana; García-González, Ángela; Tyshkovska, Iryna; González-Medina, Antonio; Soares, Sara M A; Martínez-Camblor, Pablo; Casas-Agustench, Patricia; Rabadán, Manuel; Díaz-Martínez, Ángel E; Úbeda, Natalia; Iglesias-Gutiérrez, Eduardo

    2015-07-15

    While moderate acute exercise has been associated with strong anti-inflammatory mechanisms, strenuous exercise has been linked to deleterious inflammatory perturbations. It is therefore fundamental to elucidate the mechanisms that regulate the exercise-induced inflammatory cascade. Information on novel regulators such as circulating inflammatory microRNAs (c-inflammamiRs) is incomplete. In this study, we evaluated the response of a panel of c-inflammamiRs to different doses of acute aerobic exercise. We first studied the exercise-induced inflammatory cascade in serum samples of nine active middle-aged males immediately before and after (0 h, 24 h, 72 h) 10-km, half-marathon, and marathon races. Next, we analyzed the circulating profile of 106 specific c-inflammamiRs immediately before) and after (0 h, 24 h) 10-km (low inflammatory response) and marathon (high inflammatory response) races. Analysis of classical inflammatory parameters revealed a dose-dependent effect of aerobic exercise on systemic inflammation, with higher levels detected after marathon. We observed an increase in miR-150-5p immediately after the 10-km race. Levels of 12 c-inflammamiRs were increased immediately after the marathon (let-7d-3p, let-7f-2-3p, miR-125b-5p, miR-132-3p, miR-143-3p, miR-148a-3p, miR-223-3p, miR-223-5p, miR-29a-3p, miR-34a-5p, miR-424-3p, and miR-424-5p). c-inflammamiRs returned to basal levels after 24 h. Correlation and in silico analyses supported a close association between the observed c-inflammamiR pattern and regulation of the inflammatory process. In conclusion, we found that different doses of acute aerobic exercise induced a distinct and specific c-inflammamiR response, which may be associated with control of the exercise-induced inflammatory cascade. Our findings point to c-inflammamiRs as potential biomarkers of exercise-induced inflammation, and hence, exercise dose.

  7. Effect of different doses of Manuka honey in experimentally induced mouse typhoid.

    PubMed

    Hannan, Abdul; Jabeen, Kokab; Saleem, Sidrah

    2015-05-01

    Typhoid fever is a major cause of morbidity and mortality in the developing world. Data from World Health Organization (WHO) shows that 21 million cases of typhoid occur globally every year and over 200,000 die each year; most of them at a very young age. The situation in Pakistan is similar. Typhi and other typhoidal salmonellae have developed resistance to chloramphenicol and other first line anti-typhoid. There is a rapid increase in multi-drug resistance (MDR) throughout the world. There is an urgent need to find out alternative medicine to sort out this problem. This study was conducted to establish preventive as well as therapeutic potential of Manuka honey. A total of eighty pathogen free BALB/C mice between 8 weeks to 12 weeks of age, weighing 25-30 grams were taken and divided into 4 groups. Group A, B and C were infected through oral route with 10(8) colony forming unit (CFU) of Salmonella typhimurium ATCC 14028 to produce typhoid like disease in mice. Group A, which comprised of 20 mice was further divided in A1 and A2 given Manuka honey at a dose of 15ml/kg and 20 ml/kg respectively. Group B, which comprised of 20 mice was further divided in B1 and B2 was given Manuka honey at dose of 20ml/kg and 25ml/kg respectively. Clinical features of mouse typhoid, like body temperature, respiratory rate, number of stools and general behavior were recorded twice daily. Blood cultures of mice in different groups were taken at different days to evaluate the establishment of infection as well as to observe the therapeutic and preventive potential of Manuka honey in mouse typhoid. Fisher's Exact, Chi- Square and t-test were used to analyze the data. Significant association was observed in the ultimate fate of mice in Group A1 and Group A2 (P<0.001), showing that from a total of 20 mice in both groups, 10 mice fall in Group A1 of which 10 (100%) developed infection as it was not prevented by honey at a dose of 15ml/kg body weight (15.00±0.00) in Group A1 and ten mice

  8. Effect of different doses of Manuka honey in experimentally induced mouse typhoid.

    PubMed

    Hannan, Abdul; Jabeen, Kokab; Saleem, Sidrah

    2015-05-01

    Typhoid fever is a major cause of morbidity and mortality in the developing world. Data from World Health Organization (WHO) shows that 21 million cases of typhoid occur globally every year and over 200,000 die each year; most of them at a very young age. The situation in Pakistan is similar. Typhi and other typhoidal salmonellae have developed resistance to chloramphenicol and other first line anti-typhoid. There is a rapid increase in multi-drug resistance (MDR) throughout the world. There is an urgent need to find out alternative medicine to sort out this problem. This study was conducted to establish preventive as well as therapeutic potential of Manuka honey. A total of eighty pathogen free BALB/C mice between 8 weeks to 12 weeks of age, weighing 25-30 grams were taken and divided into 4 groups. Group A, B and C were infected through oral route with 10(8) colony forming unit (CFU) of Salmonella typhimurium ATCC 14028 to produce typhoid like disease in mice. Group A, which comprised of 20 mice was further divided in A1 and A2 given Manuka honey at a dose of 15ml/kg and 20 ml/kg respectively. Group B, which comprised of 20 mice was further divided in B1 and B2 was given Manuka honey at dose of 20ml/kg and 25ml/kg respectively. Clinical features of mouse typhoid, like body temperature, respiratory rate, number of stools and general behavior were recorded twice daily. Blood cultures of mice in different groups were taken at different days to evaluate the establishment of infection as well as to observe the therapeutic and preventive potential of Manuka honey in mouse typhoid. Fisher's Exact, Chi- Square and t-test were used to analyze the data. Significant association was observed in the ultimate fate of mice in Group A1 and Group A2 (P<0.001), showing that from a total of 20 mice in both groups, 10 mice fall in Group A1 of which 10 (100%) developed infection as it was not prevented by honey at a dose of 15ml/kg body weight (15.00±0.00) in Group A1 and ten mice

  9. High-Dose-Rate Brachytherapy Boost for Prostate Cancer: Comparison of Two Different Fractionation Schemes

    SciTech Connect

    Kaprealian, Tania; Weinberg, Vivian; Speight, Joycelyn L.; Gottschalk, Alexander R.; Roach, Mack; Shinohara, Katsuto; Hsu, I.-Chow

    2012-01-01

    Purpose: This is a retrospective study comparing our experience with high-dose-rate (HDR) brachytherapy boost for prostate cancer, using two different fractionation schemes, 600 cGy Multiplication-Sign 3 fractions (patient group 1) and 950 cGy Multiplication-Sign 2 fractions (patient group 2). Methods and Materials: A total of 165 patients were treated for prostate cancer using external beam radiation therapy up to a dose of 45 Gy, followed by an HDR brachytherapy prostate radiation boost. Between July 1997 and Nov 1999, 64 patients were treated with an HDR boost of 600 cGy Multiplication-Sign 3 fractions; and between June 2000 and Nov 2005, 101 patients were treated with an HDR boost of 950 cGy Multiplication-Sign 2 fractions. All but 9 patients had at least one of the following risk features: pretreatment prostate-specific antigen (PSA) level >10, a Gleason score {>=}7, and/or clinical stage T3 disease. Results: Median follow-up was 105 months for group 1 and 43 months for group 2. Patients in group 2 had a greater number of high-risk features than group 1 (p = 0.02). Adjusted for comparable follow-up, there was no difference in biochemical no-evidence-of-disease (bNED) rate between the two fractionation scheme approaches, with 5-year Kaplan-Meier estimates of 93.5% in group 1 and 87.3% in group 2 (p = 0.19). The 5-year estimates of progression-free survival were 86% for group 1 and 83% for group 2 (p = 0.53). Among high-risk patients, there were no differences in bNED or PFS rate due to fractionation. Conclusions: Results were excellent for both groups. Adjusted for comparable follow-up, no differences were found between groups.

  10. Performance of turkey poults fed different doses of aflatoxins in the diet.

    PubMed

    Rauber, R H; Dilkin, P; Giacomini, L Z; Araújo de Almeida, C A; Mallmann, C A

    2007-08-01

    This work was conduced to determine the performance parameters of initial-phase turkey poults fed 7 different doses of aflatoxins in the diet. Three hundred thirty-six 1-d-old male turkey poults were used in this research. Turkeys were divided into 7 treatments according to aflatoxin doses (T1 = control; T2 = 20 ppb aflatoxins; T3 = 50 ppb; T4 = 100 ppb; T5 = 200 ppb; T6 = 500 ppb; T7 = 1,000 ppb). Birds were killed in 2 periods: half of them after 21 d of experiment and the remaining birds after 42 d of experiment. In both periods, the evaluated parameters were as follows: feed consumption, BW, relative weights of organs (liver, gizzard, heart, and bursa of Fabricius) and meat (breast and thighs), and clinical biochemistry parameters (total plasmatic proteins, albumin, uric acid, cholesterol, alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase). At 21 d of experiment, both feed consumption and BW were significantly affected by the aflatoxins present in the diet. Nevertheless, gizzard relative weight, total plasmatic proteins, and cholesterol levels were also affected. At the 42-d evaluation, besides feed consumption and BW, gizzard and liver relative weights and cholesterol levels were also affected by the presence of aflatoxins in the diet. Turkey poults are very sensitive to aflatoxin poisoning, because they are at least 3 to 6 times more sensitive to these contaminants than broilers.

  11. Low-intensity laser therapy to treat dentin hypersensitivity: comparative clinical study using different light doses

    NASA Astrophysics Data System (ADS)

    Lizarelli, Rosane F. Z.; Mazzetto, Marcello O.; Bagnato, Vanderlei S.

    2001-04-01

    Dentin hypersensitivity is the most common patient's complain related to pain. In fact, this is a challenge to treat specially if conventional techniques are used. The possibility to treat pain through a low intensity laser gives us an opportunity to solve this important clinical problem without promote a discomfort to patient. The main point here is not if this kind of treatment is anti- inflammatory to pulp and/or biostimulatory to production of irregular secondary dentin. The most important point here is to understand how much energy is necessary to reach conditions where to tooth become insensible to external stimulus. Our double-blinded study compared a group without laser (Placebo) with five other groups where different doses at 660 nm low intensity laser were employed. The final conclusion is that for 660 nm laser therapy, the doses from 0.13 to 2.0 J/cm2 were more efficiency than the others. The follow up care in this study was of 45 days.

  12. Emitted dose and lung deposition of inhaled terbutaline from Turbuhaler at different conditions.

    PubMed

    Abdelrahim, Mohamed E

    2010-05-01

    Turbuhaler has a very high resistance hence patient inhalation flow when using it would be low. The total emitted dose (TED) of 500microg terbutaline sulphate from a Bricanyl Turbuhaler was determined using a range of inhalation flows (10-60L min(-1)) with inhalation volume of 2 and 4L using a DPI sampling apparatus after one and two inhalations. The relative lung and systemic bioavailability of terbutaline from Bricanyl Turbuhaler when used by healthy subjects and COPD patients were determined after one and two inhalations at slow and fast inhalation flows using a novel urinary terbutaline pharmacokinetic method. The TED resulted from the one and two inhalations increased significantly (p<0.05) with the increase of the inhalation flow at both 2 and 4L inhalation volumes. The relative lung and systemic bioavailability after one inhalation at fast inhalation flow were significantly higher (p<0.01) than at slow inhalation flow in both healthy subjects and patients. Also the healthy subjects results were significantly higher (p<0.05) than the COPD patients after one inhalation. However after two inhalations there was no significant difference between slow and fast inhalation flow or healthy subjects and COPD patients. Hence it is essential to inhale twice and as deep and hard as possible from each dose of Turbuhaler for patients with low inspiratory flow and limited inhalation volume as they may not receive much benefit from one inhalation. PMID:20004090

  13. Apoptosis induced by different doses of caffeine on Chinese hamster ovary cells.

    PubMed

    Fernández, M J; López, A; Santa-Maria, A

    2003-01-01

    Caffeine has been investigated for its potential mutagenic activity to bacteria, fungi and mammalian cells in culture, and at high concentrations it is also an inducer of apoptosis. Caffeine can exert acute cellular toxicity, including inhibition of cell growth and cell death, in Chinese hamster ovary cells. The aim of this study was to evaluate the cell survival and apoptotic or non-apoptotic effects of caffeine to different concentrations in Chinese hamster ovary cells (CHO-K1). These effects were evaluated by measuring cell viability, caspase 8 activity and fragmented DNA. This study suggests that the concentration of caffeine is of critical importance because high doses of caffeine induce apoptosis and low concentrations can act as an antioxidant. Previously, the cytotoxicity of caffeine was evaluated using a wide range of concentrations by the neutral red test. From this screening, adequate doses were selected to perform the caspase activity and fragmentation DNA studies. The potential antioxidant effect of caffeine was studied using tert-butyl-hydroperoxide as a free-radical generator. The repeatability was checked through three separate tests with the same concentration.

  14. Multistep introduction of bacteria to natural substrates at different initial inoculation doses

    NASA Astrophysics Data System (ADS)

    Kupriyanov, A. A.; Semenov, A. M.; Kunenkova, N. N.; van Bruggen, A. H. C.

    2009-09-01

    The population dynamics of the saprotrophic Pseudomonas fluorescens 32 gfp bacteria and two conventionally pathogenic enterobacteria ( Escherichia coli 0157:H7 and Salmonella enterica var. Typhimurium) were investigated in their inoculation at different doses into cattle excreta and their subsequent entering soil and plants and migration through the gastroenteric tract of invertebrates. All the introduced bacteria investigated are shown to be able to overcome ecological barriers as they migrate through the natural substrates and habitats. The introduce microorganisms maintain their high population density even at the lowest initial inoculation dose—105 CFU/g of dry matter. Plants were found to be a favorable substrate for the survival of the bacteria investigated (for enteropathogens, in particular). Enteropathogens are able to pass through the gastroenteric tract of invertebrates. Therefore, these organisms can function as incubators and carriers of enteroinfections in nature.

  15. Tolerability of different dosing regimens of bisphosphonates for the treatment of osteoporosis and malignant bone disease.

    PubMed

    Bobba, Raja S; Beattie, Karen; Parkinson, Bill; Kumbhare, Dinesh; Adachi, Jonathan D

    2006-01-01

    Bisphosphonates are the primary pharmacological agents used for the management of osteoporosis and hypercalcaemia of malignant bone disease. The efficacy of these agents in these two conditions has been demonstrated in many well designed trials published over the past 2 decades. The variety of bisphosphonates currently available to us provides a wide range of tolerability and dosing profiles thus necessitating a thorough comparison of the most recent oral and intravenous bisphosphonates to differentiate the clinical context in which they should be used. Despite the fact that bisphosphonates are generally well accepted, their tolerability is dependent on complications which encompass gastrointestinal (GI) and renal toxicity. Other adverse events include osteonecrosis of the jaw, arthralgias, flu-like symptoms and uveitis. Studies have shown that various dosing regimens are able to modulate these rates of toxicity. To maximise tolerability, the direction of future therapy will likely fall into a pattern of decreasing the frequency of administration of bisphosphonates, whether it is oral or intravenous formulations, thus improving patient adherence. To review the literature on different dosing regimens of various bisphosphonates and their associated tolerability, we searched MEDLINE for articles from 1975 to 2006. Oral bisphosphonates, in particular alendronate and risedronate, have been systematically evaluated with regards to GI toxicity. Overall tolerability with these oral formulations has found GI toxicity to be the primary adverse event of interest. Both alendronate and risedronate have been found to have similar rates of GI toxicity when compared with placebo. Mounting evidence has developed validating the use of intravenous ibandronate and zoledronic acid for the purpose of treating hypercalcaemia secondary to malignancy. Unique to all other bisphosphonates, ibandronate also has an oral form which has a similar GI-toxicity profile to placebo. In addition, no

  16. Various roles of astrocytes during recovery from repeated exposure to different doses of lipopolysaccharide.

    PubMed

    Bian, Yanqing; Zhao, Xiujun; Li, Menghu; Zeng, Shaohua; Zhao, Baohua

    2013-09-15

    Previous studies have demonstrated that the outcomes associated with neuroinflammation induced by intraperitoneal injection of lipopolysaccharide (LPS) at different dosages vary and either resolve or result in sepsis. The mechanisms underlying differential recoveries from varying doses of LPS are unclear. Additionally, changes in recovery involving chronic or continuous systemic inflammatory responses remain unclear. The present experiments were designed to evaluate the effects of systemic inflammation induced by repeated intraperitoneal injection of LPS at different doses on cognitive impairment. These experiments were also designed to investigate the roles of microglia and astrocytes in systemic inflammation and confirm the mechanisms that influence these processes. Kunming mice were given intraperitoneal injections of LPS at either 5mg/kg or 10mg/kg or saline for 7 consecutive days. Following the 7-day course of injections, a number of mice were kept undisturbed in their home cage for 30 days (30-day recovery), and other mice were similarly kept for 90 days (90-day recovery). The results revealed that the cognitive and physiological changes induced by 5mg/kg LPS included weight loss, impairments in spatial learning and memory, phenotypic changes in glia cells, and altered levels of pro-inflammatory cytokines; all of which were reversible. A potential recovery mechanism involves a neuroprotective function of activated astrocytes that secreted glial-derived neurotrophic factor (GDNF) following 30-day recovery. The changes induced by 10mg/kg LPS included weight loss, phenotypic changes in glia cells, and altered levels of pro-inflammatory cytokines were also reversible; however, a longer recovery was required (90 days). Although 10mg/kg LPS-induced neuroinflammation was reversible, the associated impairments in spatial learning and memory were permanent. A potential mechanism underlying permanent damage associated with 10mg/kg LPS involves the role of the activated

  17. Measurement of eye lens dose for Varian On-Board Imaging with different cone-beam computed tomography acquisition techniques

    PubMed Central

    Deshpande, Sudesh; Dhote, Deepak; Thakur, Kalpna; Pawar, Amol; Kumar, Rajesh; Kumar, Munish; Kulkarni, M. S.; Sharma, S. D.; Kannan, V.

    2016-01-01

    The objective of this work was to measure patient eye lens dose for different cone-beam computed tomography (CBCT) acquisition protocols of Varian's On-Board Imaging (OBI) system using optically stimulated luminescence dosimeter (OSLD) and to study the variation in eye lens dose with patient geometry and distance of isocenter to the eye lens. During the experimental measurements, OSLD was placed on the patient between the eyebrows of both eyes in line of nose during CBCT image acquisition to measure eye lens doses. The eye lens dose measurements were carried out for three different cone-beam acquisition protocols (standard dose head, low-dose head [LDH], and high-quality head [HQH]) of Varian OBI. Measured doses were correlated with patient geometry and distance between isocenter and eye lens. Measured eye lens doses for standard head and HQH protocols were in the range of 1.8–3.2 mGy and 4.5–9.9 mGy, respectively. However, the measured eye lens dose for the LDH protocol was in the range of 0.3–0.7 mGy. The measured data indicate that eye lens dose to patient depends on the selected imaging protocol. It was also observed that eye lens dose does not depend on patient geometry but strongly depends on distance between eye lens and treatment field isocenter. However, undoubted advantages of imaging system should not be counterbalanced by inappropriate selection of imaging protocol, especially for very intense imaging protocol. PMID:27651564

  18. Absolute and relative dosimetry for ELIMED

    SciTech Connect

    Cirrone, G. A. P.; Schillaci, F.; Scuderi, V.; Cuttone, G.; Candiano, G.; Musumarra, A.; Pisciotta, P.; Romano, F.; Carpinelli, M.; Presti, D. Lo; Raffaele, L.; Tramontana, A.; Cirio, R.; Sacchi, R.; Monaco, V.; Marchetto, F.; Giordanengo, S.

    2013-07-26

    The definition of detectors, methods and procedures for the absolute and relative dosimetry of laser-driven proton beams is a crucial step toward the clinical use of this new kind of beams. Hence, one of the ELIMED task, will be the definition of procedures aiming to obtain an absolute dose measure at the end of the transport beamline with an accuracy as close as possible to the one required for clinical applications (i.e. of the order of 5% or less). Relative dosimetry procedures must be established, as well: they are necessary in order to determine and verify the beam dose distributions and to monitor the beam fluence and the energetic spectra during irradiations. Radiochromic films, CR39, Faraday Cup, Secondary Emission Monitor (SEM) and transmission ionization chamber will be considered, designed and studied in order to perform a fully dosimetric characterization of the ELIMED proton beam.

  19. Small angle neutron scattering on an absolute intensity scale and the internal surface of diatom frustules from three species of differing morphologies.

    PubMed

    Garvey, C J; Strobl, M; Percot, A; Saroun, J; Haug, J; Vyverman, W; Chepurnov, V A; Ferris, J M

    2013-05-01

    The internal nanostructure of the diatoms Cyclotella meneghiniana, Seminavis robusta and Achnanthes subsessilis was investigated using small angle neutron scattering (SANS) to examine thin biosilica samples, consisting of isotropic (powder) from their isolated cell walls. The interpretation of SANS data was assisted by several other measurements. The N2 adsorption, interpreted within the Branuer-Emmet-Teller isotherm, yielded the specific surface area of the material. Fourier transform infrared (FTIR) and Raman spectroscopy indicates that the isolated material is amorphous silica with small amounts of organic cell wall materials acting as a filling material between the silica particles. A two-phase (air and amorphous silica) model was used to interpret small angle neutron scattering data. After correction for instrumental resolution, the measurements on two SANS instruments covered an extended range of scattering vectors 0.0011 nm(-1) < q < 5.6 nm(-1), giving an almost continuous SANS curve over a range of scattering vectors, q, on an absolute scale of intensity for each sample. Each of the samples gave a characteristic scattering curve where log (intensity) versus log (q) has a -4 dependence, with other features superimposed. In the high-q regime, departure from this behaviour was observed at a length-scales equivalent to the proposed unitary silica particle. The limiting Porod scattering law was used to determine the specific area per unit of volume of each sample illuminated by the neutron beam. The Porod behaviour, and divergence from this behaviour, is discussed in terms of various structural features and the proposed mechanisms for the bio-assembly of unitary silica particles in frustules.

  20. Absolute x-ray dosimetry on a synchrotron medical beam line with a graphite calorimeter

    SciTech Connect

    Harty, P. D. Ramanathan, G.; Butler, D. J.; Johnston, P. N.; Lye, J. E.; Hall, C. J.; Stevenson, A. W.

    2014-05-15

    Purpose: The absolute dose rate of the Imaging and Medical Beamline (IMBL) on the Australian Synchrotron was measured with a graphite calorimeter. The calorimetry results were compared to measurements from the existing free-air chamber, to provide a robust determination of the absolute dose in the synchrotron beam and provide confidence in the first implementation of a graphite calorimeter on a synchrotron medical beam line. Methods: The graphite calorimeter has a core which rises in temperature when irradiated by the beam. A collimated x-ray beam from the synchrotron with well-defined edges was used to partially irradiate the core. Two filtration sets were used, one corresponding to an average beam energy of about 80 keV, with dose rate about 50 Gy/s, and the second filtration set corresponding to average beam energy of 90 keV, with dose rate about 20 Gy/s. The temperature rise from this beam was measured by a calibrated thermistor embedded in the core which was then converted to absorbed dose to graphite by multiplying the rise in temperature by the specific heat capacity for graphite and the ratio of cross-sectional areas of the core and beam. Conversion of the measured absorbed dose to graphite to absorbed dose to water was achieved using Monte Carlo calculations with the EGSnrc code. The air kerma measurements from the free-air chamber were converted to absorbed dose to water using the AAPM TG-61 protocol. Results: Absolute measurements of the IMBL dose rate were made using the graphite calorimeter and compared to measurements with the free-air chamber. The measurements were at three different depths in graphite and two different filtrations. The calorimetry measurements at depths in graphite show agreement within 1% with free-air chamber measurements, when converted to absorbed dose to water. The calorimetry at the surface and free-air chamber results show agreement of order 3% when converted to absorbed dose to water. The combined standard uncertainty is 3

  1. The Effect of Different Doses of Cigarette Smoke in a Mouse Lung Tumor Model

    PubMed Central

    Santiago, Ludmilla Nadir; de Camargo Fenley, Juliana; Braga, Lúcia Campanario; Cordeiro, José Antônio; Cury, Patrícia M.

    2009-01-01

    Few studies have used Balb/c mice as an animal model for lung carcinogenesis. In this study, we investigated the effect of different doses of cigarette smoking in the urethane-induced Balb/c mouse lung cancer model. After injection of 3mg/kg urethane intraperitoneally, the mice were then exposed to tobacco smoke once or twice a day, five times a week, in a closed chamber. The animals were randomly divided into four groups. The control group (G0) received urethane only. The experimental groups (G1, G2 and G3) received urethane and exposure to the smoke of 3 cigarettes for 10 minutes once a day, 3 cigarettes for 10 minutes twice a day, and 6 cigarettes for 10 minutes twice a day, respectively. The mice were sacrificed after 16 weeks of exposure, and the number of nodules and hyperplasia in the lungs was counted. The results showed no statistically significant difference in the mean number of nodules and hyperplasia among the different groups, suggesting that the Balb/c mice are not suitable to study the pathogenesis of tobacco smoking-induced tumor progression in the lungs. PMID:19079653

  2. Comparison of distribution and toxicity following repeated oral dosing of different vanadium oxide nanoparticles in mice.

    PubMed

    Park, Eun-Jung; Lee, Gwang-Hee; Yoon, Cheolho; Kim, Dong-Wan

    2016-10-01

    Vanadium is an important ultra-trace element derived from fuel product combustion. With the development of nanotechnology, vanadium oxide nanoparticles (VO NPs) have been considered for application in various fields, thus the possibility of release into the environment and human exposure is also increasing. Considering that verification of bioaccumulation and relevant biological responses are essential for safe application of products, in this study, we aimed to identify the physicochemical properties that determine their health effects by comparing the biological effects and tissue distribution of different types of VO NPs in mice. For this, we prepared five types of VO NPs, commercial (C)-VO2 and -V2O5 NPs and synthetic (S)-VO2, -V2O3, and -V2O5 NPs. While the hydrodynamic diameter of the two types of C-VO NPs was irregular and impossible to measure, those of the three types of S-VO NPs was in the range of 125-170nm. The S- and C-V2O5 NPs showed higher dissolution rates compared to other VO NPs. We orally dosed the five types of VO NPs (70 and 210μg/mouse, approximately 2 and 6mg/kg) to mice for 28 days and compared their biodistribution and toxic effects. We found that S-V2O5 and S-V2O3 NPs more accumulated in tissues compared to other three types of VO NPs, and the accumulated level was in order of heart>liver>kidney>spleen. Additionally, tissue levels of redox reaction-related elements and electrolytes (Na(+), K(+), and Ca(2+)) were most clearly altered in the heart of treated mice. Notably, all S- and C-VO NPs decreased the number of WBCs at the higher dose, while total protein and albumin levels were reduced at the higher dose of S-V2O5 and S-V2O3 NPs. Taken together, we conclude that the biodistribution and toxic effects of VO NPs depend on their dissolution rates and size (surface area). Additionally, we suggest that further studies are needed to clarify effects of VO NPs on functions of the heart and the immune system.

  3. ABSOLUTE POLARIMETRY AT RHIC.

    SciTech Connect

    OKADA; BRAVAR, A.; BUNCE, G.; GILL, R.; HUANG, H.; MAKDISI, Y.; NASS, A.; WOOD, J.; ZELENSKI, Z.; ET AL.

    2007-09-10

    Precise and absolute beam polarization measurements are critical for the RHIC spin physics program. Because all experimental spin-dependent results are normalized by beam polarization, the normalization uncertainty contributes directly to final physics uncertainties. We aimed to perform the beam polarization measurement to an accuracy Of {Delta}P{sub beam}/P{sub beam} < 5%. The absolute polarimeter consists of Polarized Atomic Hydrogen Gas Jet Target and left-right pairs of silicon strip detectors and was installed in the RHIC-ring in 2004. This system features proton-proton elastic scattering in the Coulomb nuclear interference (CNI) region. Precise measurements of the analyzing power A{sub N} of this process has allowed us to achieve {Delta}P{sub beam}/P{sub beam} = 4.2% in 2005 for the first long spin-physics run. In this report, we describe the entire set up and performance of the system. The procedure of beam polarization measurement and analysis results from 2004-2005 are described. Physics topics of AN in the CNI region (four-momentum transfer squared 0.001 < -t < 0.032 (GeV/c){sup 2}) are also discussed. We point out the current issues and expected optimum accuracy in 2006 and the future.

  4. Dose Distributions of an 192Ir Brachytherapy Source in Different Media

    PubMed Central

    Wu, C. H.; Liao, Y. J.; Liu, Y. W. Hsueh; Hung, S. K.; Lee, M. S.; Hsu, S. M.

    2014-01-01

    This study used MCNPX code to investigate the brachytherapy 192Ir dose distributions in water, bone, and lung tissue and performed radiophotoluminescent glass dosimeter measurements to verify the obtained MCNPX results. The results showed that the dose-rate constant, radial dose function, and anisotropy function in water were highly consistent with data in the literature. However, the lung dose near the source would be overestimated by up to 12%, if the lung tissue is assumed to be water, and, hence, if a tumor is located in the lung, the tumor dose will be overestimated, if the material density is not taken into consideration. In contrast, the lung dose far from the source would be underestimated by up to 30%. Radial dose functions were found to depend not only on the phantom size but also on the material density. The phantom size affects the radial dose function in bone more than those in the other tissues. On the other hand, the anisotropy function in lung tissue was not dependent on the radial distance. Our simulation results could represent valid clinical reference data and be used to improve the accuracy of the doses delivered during brachytherapy applied to patients with lung cancer. PMID:24804263

  5. Influence trend of temperature distribution in skin tissue generated by different exposure dose pulse laser

    NASA Astrophysics Data System (ADS)

    Shan, Ning; Wang, Zhijing; Liu, Xia

    2014-11-01

    Laser is widely applied in military and medicine fields because of its excellent capability. In order to effectively defend excess damage by laser, the thermal processing theory of skin tissue generated by laser should be carried out. The heating rate and thermal damage area should be studied. The mathematics model of bio-tissue heat transfer that is irradiated by laser is analyzed. And boundary conditions of bio-tissue are discussed. Three layer FEM grid model of bio-tissue is established. The temperature rising inducing by pulse laser in the tissue is modeled numerically by adopting ANSYS software. The changing trend of temperature in the tissue is imitated and studied under the conditions of different exposure dose pulse laser. The results show that temperature rising in the tissue depends on the parameters of pulse laser largely. In the same conditions, the pulse width of laser is smaller and its instant power is higher. And temperature rising effect in the tissue is very clear. On the contrary, temperature rising effect in the tissue is lower. The cooling time inducing by temperature rising effect in the tissue is longer along with pulse separation of laser is bigger. And the temperature difference is bigger in the pulse period.

  6. Computational Modeling of Cellular Effects Post-Irradiation with Low- and High-Let Particles and Different Absorbed Doses

    PubMed Central

    Tavares, Adriana Alexandre S.; Tavares, João Manuel R. S.

    2013-01-01

    The use of computational methods to improve the understanding of biological responses to various types of radiation is an approach where multiple parameters can be modelled and a variety of data is generated. This study compares cellular effects modelled for low absorbed doses against high absorbed doses. The authors hypothesized that low and high absorbed doses would contribute to cell killing via different mechanisms, potentially impacting on targeted tumour radiotherapy outcomes. Cellular kinetics following irradiation with selective low- and high-linear energy transfer (LET) particles were investigated using the Virtual Cell (VC) radiobiology algorithm. Two different cell types were assessed using the VC radiobiology algorithm: human fibroblasts and human crypt cells. The results showed that at lower doses (0.01 to 0.2 Gy), all radiation sources used were equally able to induce cell death (p>0.05, ANOVA). On the other hand, at higher doses (1.0 to 8.0 Gy), the radiation response was LET and dose dependent (p<0.05, ANOVA). The data obtained suggests that the computational methods used might provide some insight into the cellular effects following irradiation. The results also suggest that it may be necessary to re-evaluate cellular radiation-induced effects, particularly at low doses that could affect therapeutic effectiveness. PMID:23930101

  7. SU-E-P-11: Comparison of Image Quality and Radiation Dose Between Different Scanner System in Routine Abdomen CT

    SciTech Connect

    Liao, S; Wang, Y; Weng, H

    2015-06-15

    Purpose To evaluate image quality and radiation dose of routine abdomen computed tomography exam with the automatic current modulation technique (ATCM) performed in two different brand 64-slice CT scanners in our site. Materials and Methods A retrospective review of routine abdomen CT exam performed with two scanners; scanner A and scanner B in our site. To calculate standard deviation of the portal hepatic level with a region of interest of 12.5 mm x 12.5mm represented to the image noise. The radiation dose was obtained from CT DICOM image information. Using Computed tomography dose index volume (CTDIv) to represented CT radiation dose. The patient data in this study were with normal weight (about 65–75 Kg). Results The standard deviation of Scanner A was smaller than scanner B, the scanner A might with better image quality than scanner B. On the other hand, the radiation dose of scanner A was higher than scanner B(about higher 50–60%) with ATCM. Both of them, the radiation dose was under diagnostic reference level. Conclusion The ATCM systems in modern CT scanners can contribute a significant reduction in radiation dose to the patient. But the reduction by ATCM systems from different CT scanner manufacturers has slightly variation. Whatever CT scanner we use, it is necessary to find the acceptable threshold of image quality with the minimum possible radiation exposure to the patient in agreement with the ALARA principle.

  8. Dose conversion coefficients for monoenergetic electrons incident on a realistic human eye model with different lens cell populations

    NASA Astrophysics Data System (ADS)

    Nogueira, P.; Zankl, M.; Schlattl, H.; Vaz, P.

    2011-11-01

    The radiation-induced posterior subcapsular cataract has long been generally accepted to be a deterministic effect that does not occur at doses below a threshold of at least 2 Gy. Recent epidemiological studies indicate that the threshold for cataract induction may be much lower or that there may be no threshold at all. A thorough study of this subject requires more accurate dose estimates for the eye lens than those available in ICRP Publication 74. Eye lens absorbed dose per unit fluence conversion coefficients for electron irradiation were calculated using a geometrical model of the eye that takes into account different cell populations of the lens epithelium, together with the MCNPX Monte Carlo radiation transport code package. For the cell population most sensitive to ionizing radiation—the germinative cells—absorbed dose per unit fluence conversion coefficients were determined that are up to a factor of 4.8 higher than the mean eye lens absorbed dose conversion coefficients for electron energies below 2 MeV. Comparison of the results with previously published values for a slightly different eye model showed generally good agreement for all electron energies. Finally, the influence of individual anatomical variability was quantified by positioning the lens at various depths below the cornea. A depth difference of 2 mm between the shallowest and the deepest location of the germinative zone can lead to a difference between the resulting absorbed doses of up to nearly a factor of 5000 for electron energy of 0.7 MeV.

  9. Sterility and Sexual Competitiveness of Tapachula-7 Anastrepha ludens Males Irradiated at Different Doses

    PubMed Central

    Orozco-Dávila, Dina; Adriano-Anaya, Maria de Lourdes; Quintero-Fong, Luis; Salvador-Figueroa, Miguel

    2015-01-01

    A genetic sexing strain of Anastrepha ludens (Loew), Tapachula-7, was developed by the Mexican Program Against Fruit Flies to produce and release only males in programs where the sterile insect technique (SIT) is applied. Currently, breeding are found at a massive scale, and it is necessary to determine the optimum irradiation dose that releases sterile males with minimum damage to their sexual competitiveness. Under laboratory and field conditions, we evaluated the effects of gamma irradiation at doses of 0, 20, 40, 60 and 80 Gy on the sexual competitiveness of males, the induction of sterility in wild females and offspring survivorship. The results of the study indicate that irradiation doses have a significant effect on the sexual behavior of males. A reduction of mating capacity was inversely proportional to the irradiation dose of males. It is estimated that a dose of 60 Gy can induce more than 99% sterility in wild females. In all treatments, the degree of offspring fertility was correlated with the irradiation dose of the parents. In conclusion, the results of the study indicate that a dose of 60 Gy can be applied in sterile insect technique release programs. The application of this dose in the new genetic sexing strain of A. ludens is discussed. PMID:26274926

  10. SU-E-J-07: IGRT Gently: Evaluating Imaging Dose in Phantoms of Different Sizes

    SciTech Connect

    Morris, B; Duggar, W; Stanford, J; Yang, C

    2015-06-15

    Purpose: IGRT imaging procedures have emerged as a common method of patient position verification in radiotherapy, though imaging dose is generally neglected in the treatment plan. Consequently, evaluating and optimizing the dose from these procedures is worthwhile. This process is especially important for children, who are more radiosensitive than adults. The aim of this work was to gain some understanding of the relative doses involved with various XVI-preset parameters for an “adult” and “child” phantom set, with the hopes that imaging dose for a child can be reduced. Methods: 32 and 16cm CTDI-phantoms were used as surrogates for adult and child torsos, respectively. Dose was measured in the central and peripheral chamber positions of the phantoms. CBCT scans were made for both phantoms using Elekta’s Chest-preset to establish a dose baseline. The child-phantom was then scanned using the Elekta Head and Neck (HN) preset. A modified HN-preset (named Peds Abd-pelvis) was also created with a doubled mAs to maintain a reduction in dose to the child-phantom (relative to the baseline), while providing clinically-usable image quality. Results: The baseline dose to the child-phantom from the Chest-preset was 310% that of the adult-phantom for the center chamber position and 150% at the periphery. An average dose reduction of 97% was obtained in the childphantom by switching from the Chest-preset to the HN-preset, while the Peds Abd-pelvis-preset similarly reduced the dose by an average of 92%. Conclusion: XVI-preset parameters significantly affect dose, and should be optimized to reduce dose, while ensuring clinically-usable image quality. Using a modified imaging preset (Peds Abd-pelvis-preset) greatly reduced the dose to the child-phantom compared to the dose for the Chest-preset for both the child and adult-phantoms. This outcome provides support for the development of child-specific protocols for IGRT imaging in pediatric patients.

  11. Radiosensitivity of human clonogenic myeloma cells and normal bone marrow precursors: Effect of different dose rates and fractionation

    SciTech Connect

    Glueck, S.; Van Dyk, J.; Messner, H.A. )

    1994-03-01

    Evaluation of radiation dose rate and fractionation effects on clonogenic myeloma cells was carried out. The radiosensitivity of clonogenic myeloma cells was evaluated for seven human myeloma cell lines. The lines were maintained in liquid suspension culture. Following radiation, cells were plated in semisolid medium using methylcellulose as viscous support. Radiation doses up to 12 Gy were delivered at dose rates of 0.05 and 0.5 Gy/min by a [sup 60]Co source. Each total dose was administered either as a single dose or in multiple fractions of 2 Gy. The data were analyzed according to the linear quadratic and multi target model of irradiation. Clonogenic progenitors of the seven myeloma cell lines differed in their radiosensitivity as measured by multiple parameters. The differences were mainly observed at low dose. The most effective cytoreduction was seen when radiation was administered in a single fraction at high dose rate. The cytoreductive effect on clonogenic myeloma cells was compared for clinically practiced total body irradiation (TBI) schedules delivered either in a single or in multiple fractions without causing significant pulmonary toxicity. The administration of 12 Gy delivered in six fractions of 2 Gy resulted in a superior reduction of clonogenic cells compared to a single fraction of 5 Gy. The preparation of bone marrow transplant recipients with multiple myeloma using fractionated radiation with a total dose of 12 Gy appears to afford better ablation than a single dose of 5 Gy while maintaining a low incidence of pulmonary toxicity. 20 refs., 4 figs., 4 tabs.

  12. Apparent absence of a proton beam dose rate effect and possible differences in RBE between Bragg peak and plateau

    SciTech Connect

    Matsuura, Taeko; Egashira, Yusuke; Nishio, Teiji; Matsumoto, Yoshitaka; Wada, Mami; Koike, Sachiko; Furusawa, Yoshiya; Kohno, Ryosuke; Nishioka, Shie; Kameoka, Satoru; Tsuchihara, Katsuya; Kawashima, Mitsuhiko; Ogino, Takashi

    2010-10-15

    Purpose: Respiration-gated irradiation for a moving target requires a longer time to deliver single fraction in proton radiotherapy (PRT). Ultrahigh dose rate (UDR) proton beam, which is 10-100 times higher than that is used in current clinical practice, has been investigated to deliver daily dose in single breath hold duration. The purpose of this study is to investigate the survival curve and relative biological effectiveness (RBE) of such an ultrahigh dose rate proton beam and their linear energy transfer (LET) dependence. Methods: HSG cells were irradiated by a spatially and temporally uniform proton beam at two different dose rates: 8 Gy/min (CDR, clinical dose rate) and 325 Gy/min (UDR, ultrahigh dose rate) at the Bragg peak and 1.75 (CDR) and 114 Gy/min (UDR) at the plateau. To study LET dependence, the cells were positioned at the Bragg peak, where the absorbed dose-averaged LET was 3.19 keV/{mu}m, and at the plateau, where it was 0.56 keV/{mu}m. After the cell exposure and colony assay, the measured data were fitted by the linear quadratic (LQ) model and the survival curves and RBE at 10% survival were compared. Results: No significant difference was observed in the survival curves between the two proton dose rates. The ratio of the RBE for CDR/UDR was 0.98{+-}0.04 at the Bragg peak and 0.96{+-}0.06 at the plateau. On the other hand, Bragg peak/plateau RBE ratio was 1.15{+-}0.05 for UDR and 1.18{+-}0.07 for CDR. Conclusions: Present RBE can be consistently used in treatment planning of PRT using ultrahigh dose rate radiation. Because a significant increase in RBE toward the Bragg peak was observed for both UDR and CDR, further evaluation of RBE enhancement toward the Bragg peak and beyond is required.

  13. Toxicogenomic analysis of placenta samples from mice exposed to different doses of BPA.

    PubMed

    Tait, Sabrina; Tassinari, Roberta; Maranghi, Francesca; Mantovani, Alberto

    2015-06-01

    Bisphenol A (BPA), a widespread Endocrine Disrupter mainly used in food contact plastics, may induce adverse effects especially on susceptible lifestages, first of all pregnancy. The present study considered placental development as a potential target of BPA and investigated potential differences in the modes of action of two doses of BPA by a toxicogenomic approach. Pregnant CD-1 mice were administered with vehicle, 0.5 (BPA05) or 50 mg/kg (BPA50) body weight (bw)/die of BPA, from gestational day (GD) 1 to GD11. At GD12 dams were sacrificed and transcriptomic analysis was performed on placenta samples. Histological, histomorphometrical and immunohistochemical analyses were also performed to phenotypically anchor transcriptional changes associated with BPA exposure. The interpretation and description of the overall data are included in a manuscript under revision [1]. Here we describe the experimental design and the analysis performed on the gene expression data which are publicly available through the Gene Expression Omnibus (GEO) database with accession number GSE63852.

  14. Toxicogenomic analysis of placenta samples from mice exposed to different doses of BPA.

    PubMed

    Tait, Sabrina; Tassinari, Roberta; Maranghi, Francesca; Mantovani, Alberto

    2015-06-01

    Bisphenol A (BPA), a widespread Endocrine Disrupter mainly used in food contact plastics, may induce adverse effects especially on susceptible lifestages, first of all pregnancy. The present study considered placental development as a potential target of BPA and investigated potential differences in the modes of action of two doses of BPA by a toxicogenomic approach. Pregnant CD-1 mice were administered with vehicle, 0.5 (BPA05) or 50 mg/kg (BPA50) body weight (bw)/die of BPA, from gestational day (GD) 1 to GD11. At GD12 dams were sacrificed and transcriptomic analysis was performed on placenta samples. Histological, histomorphometrical and immunohistochemical analyses were also performed to phenotypically anchor transcriptional changes associated with BPA exposure. The interpretation and description of the overall data are included in a manuscript under revision [1]. Here we describe the experimental design and the analysis performed on the gene expression data which are publicly available through the Gene Expression Omnibus (GEO) database with accession number GSE63852. PMID:26484192

  15. Effects of Different Doses of Physical Activity on C-Reactive Protein Among Women

    PubMed Central

    Stewart, Laura K.; Earnest, Conrad P.; Blair, Steven N.; Church, Timothy S.

    2009-01-01

    Elevated C-reactive protein (CRP) is associated with an increased risk of cardiovascular disease. Physical activity has been inversely associated with CRP. However, the clinical trials examining the effect of exercise training have produced conflicting results. Purpose The purpose of this study was to examine the influence an exercise training program on CRP in postmenopausal women. Methods Sedentary, overweight/obese, postmenopausal women with elevated systolic blood pressure (120.0 to 159.9 mm Hg) (N= 464) were randomized into 1 of 4 groups: a non-exercise control or 1 of 3 aerobic exercise groups; exercise energy expenditure of 4, 8, or 12 kcal/kg/week (KKW), for 6 months at a training intensity of 50% of peak VO2. Results Complete data was available of 421 participants and mean baseline CRP was 5.7 (5.5) mg/L with no significant differences across groups. While VO2 increased in a dose response manner, there were no significant changes in CRP in any of the exercise intervention groups compared to the control group. Change in fitness was not associated with change in CRP, whereas change in weight was significantly associated with change in CRP. Conclusion Despite increasing fitness, six months of aerobic exercise training did not improve CRP. However, improvements in CRP were associated with reductions in weight. PMID:19952829

  16. Characterization of differences in calculated and actual measured skin doses to canine limbs during stereotactic radiosurgery using Gafchromic film

    SciTech Connect

    Walters, Jerri; Ryan, Stewart; Harmon, Joseph F.

    2012-07-01

    Accurate calculation of absorbed dose to the skin, especially the superficial and radiosensitive basal cell layer, is difficult for many reasons including, but not limited to, the build-up effect of megavoltage photons, tangential beam effects, mixed energy scatter from support devices, and dose interpolation caused by a finite resolution calculation matrix. Stereotactic body radiotherapy (SBRT) has been developed as an alternative limb salvage treatment option at Colorado State University Veterinary Teaching Hospital for dogs with extremity bone tumors. Optimal dose delivery to the tumor during SBRT treatment can be limited by uncertainty in skin dose calculation. The aim of this study was to characterize the difference between measured and calculated radiation dose by the Varian Eclipse (Varian Medical Systems, Palo Alto, CA) AAA treatment planning algorithm (for 1-mm, 2-mm, and 5-mm calculation voxel dimensions) as a function of distance from the skin surface. The study used Gafchromic EBT film (International Specialty Products, Wayne, NJ), FilmQA analysis software, a limb phantom constructed from plastic water Trade-Mark-Sign (fluke Biomedical, Everett, WA) and a canine cadaver forelimb. The limb phantom was exposed to 6-MV treatments consisting of a single-beam, a pair of parallel opposed beams, and a 7-beam coplanar treatment plan. The canine forelimb was exposed to the 7-beam coplanar plan. Radiation dose to the forelimb skin at the surface and at depths of 1.65 mm and 1.35 mm below the skin surface were also measured with the Gafchromic film. The calculation algorithm estimated the dose well at depths beyond buildup for all calculation voxel sizes. The calculation algorithm underestimated the dose in portions of the buildup region of tissue for all comparisons, with the most significant differences observed in the 5-mm calculation voxel and the least difference in the 1-mm voxel. Results indicate a significant difference between measured and calculated data

  17. Behavioural thermoregulation in mice: effects of low doses of general anaesthetics of different potency.

    PubMed

    Pertwee, R G; Marshall, N R; Macdonald, A G

    1990-09-01

    Chloroform, monochlorodifluoromethane and nitrous oxide produced dose-related decreases in the rectal temperatures of mice allowed to choose between a warm and a cool environment. The doses used were subanaesthetic, respectively 0.0013-0.004, 0.028-0.085 and 0.25-0.5 atm. The hypothermia (up to 3.6 degrees C) was usually associated with significant reductions in time spent in the warm. The log dose-hypothermic response plots were approximately parallel and there was a marked correlation between anaesthetic potency, as measured by the abolition of the righting response, and hypothermic potency.

  18. Effects of different doses of nandrolone decanoate on estrous cycle and ovarian tissue of rats after treatment and recovery periods.

    PubMed

    Simão, Vinícius Augusto; Berloffa Belardin, Larissa; Araújo Leite, Gabriel Adan; de Almeida Chuffa, Luiz Gustavo; Camargo, Isabel Cristina Cherici

    2015-10-01

    This study tested the hypothesis that different doses of nandrolone decanoate (ND) will cause changes in the estrous cycle and ovarian tissue of adult rats; and investigated the duration of the recovery period that is sufficient to restore the damage in the animals treated with different doses. Wistar rats were treated with ND at doses of 1.87, 3.75, 7.5 and 15 mg/kg body weight, or received mineral oil (control group) for 15 days, subcutaneously. All animals were divided into three groups according to the treatment periods: (i) ND treatment for 15 days; (ii) ND treatment followed by a 30-day recovery; and (iii) ND treatment followed by a 60-day recovery. Estrous cycle was monitored daily, and at the end of each period, the animals were euthanized for histopathological analysis. During ND treatment and after 30-day recovery, all animals exhibited persistent diestrus. After a 60-day recovery, persistent diestrus was only maintained in the group that had received the highest dose. Ovarian weight was decreased significantly after the 30-day recovery, regardless of ND doses, compared with the control group. There was a reduction (P < 0.05) in the number of corpora lutea and antral and growing follicles, in contrast to an increase (P < 0.05) in atretic follicles in a dose- and time-dependent manner. Remarkable histopathological changes occurred in the ovaries of all ND-treated groups. In conclusion, the different doses of ND caused changes in the estrous cycle and ovarian tissue of rats, and recovery periods (30 and 60 days) were insufficient to completely restore the damage in the animals treated with the highest dose. PMID:26575430

  19. Comparison of elicitation potential of chloroatranol and atranol--2 allergens in oak moss absolute.

    PubMed

    Johansen, Jeanne D; Bernard, Guillaume; Giménez-Arnau, Elena; Lepoittevin, Jean-Pierre; Bruze, Magnus; Andersen, Klaus E

    2006-04-01

    Chloroatranol and atranol are degradation products of chloroatranorin and atranorin, respectively, and have recently been identified as important contact allergens in the natural fragrance extract, oak moss absolute. Oak moss absolute is widely used in perfumery and is the cause of many cases of fragrance allergic contact dermatitis. Chloroatranol elicits reactions at very low levels of exposure. In oak moss absolute, chloroatranol and atranol are present together and both may contribute to the allergenicity and eliciting capacity of the natural extract. In this study, 10 eczema patients with known sensitization to chloroatranol and oak moss absolute were tested simultaneously to a serial dilution of chloroatranol and atranol in ethanol, in equimolar concentrations (0.0034-1072 microM). Dose-response curves were estimated and analysed by logistic regression. The estimated difference in elicitation potency of chloroatranol relative to atranol based on testing with equimolar concentrations was 217% (95% confidence interval 116-409%). Both substances elicited reactions at very low levels of exposure. It is concluded that the differences in elicitation capacity between the 2 substances are counterbalanced by exposure being greater to atranol than to chloroatranol and that both substances contribute to the clinical problems seen in oak moss absolute-sensitized individuals. PMID:16650093

  20. Immune reconstitution after haematopoietic transplantation with two different doses of pre-graft antithymocyte globulin.

    PubMed

    Duval, M; Pédron, B; Rohrlich, P; Legrand, F; Faye, A; Lescoeur, B; Bensaid, P; Larchee, R; Sterkers, G; Vilmer, E

    2002-10-01

    Antithymocyte globulin is widely used before haematopoietic transplantation with HLA-matched unrelated donors or mismatched relatives to prevent rejection and graft-versus-host disease (GVHD). However, optimal dosage is still under debate. Thirty-one consecutive children, mainly with haematological malignancies, were transplanted in a single institution with such donors, selected by HLA-A -B compatibility by serology and DRB1* by DNA typing. Antithymocyte globulin (Thymoglobuline; Sangstat) was infused at days -3, -2, -1. Total dosage varied: 16 patients received a median of 7.5 mg/kg (2.5 to 10.5: low-dose group), and 15 a median of 15.5 mg/kg (14.4 to 19.4: high-dose group). Post-transplant GVHD prophylaxis consisted of cyclosporine, short-course methotrexate and steroids. CD3(+), CD4(+) and CD19(+) cell reconstitution was slower in the high-dose group. Median time to reach 100 CD4(+) cells was 8 months vs 4 months (P = 0.03). Median time to normal CD19(+) cells was 16 months vs 8 months (P = 0.01). CD16(+)CD56(+) and CD8(+) cell reconstitution was similar. Nine patients in the high-dose group and two in the low-dose group experienced life-threatening opportunistic infections (P = 0.009). Although obtained from a limited number of patients, our data suggest that a higher pre-graft dose of antithymocyte globulin may negatively influence immune reconstitution.

  1. Sex differences in nicotine self-administration in rats during progressive unit dose reduction: implications for nicotine regulation policy.

    PubMed

    Grebenstein, Patricia; Burroughs, Danielle; Zhang, Yan; LeSage, Mark G

    2013-12-01

    Reducing the nicotine content in tobacco products is being considered by the FDA as a policy to reduce the addictiveness of tobacco products. Understanding individual differences in response to nicotine reduction will be critical to developing safe and effective policy. Animal and human research demonstrating sex differences in the reinforcing effects of nicotine suggests that males and females may respond differently to nicotine-reduction policies. However, no studies have directly examined sex differences in the effects of nicotine unit-dose reduction on nicotine self-administration (NSA) in animals. The purpose of the present study was to examine this issue in a rodent self-administration model. Male and female rats were trained to self-administer nicotine (0.06mg/kg) under an FR 3 schedule during daily 23h sessions. Rats were then exposed to saline extinction and reacquisition of NSA, followed by weekly reductions in the unit dose (0.03 to 0.00025mg/kg) until extinction levels of responding were achieved. Males and females were compared with respect to baseline levels of intake, resistance to extinction, degree of compensatory increases in responding during dose reduction, and the threshold reinforcing unit dose of nicotine. Exponential demand-curve analysis was also conducted to compare the sensitivity of males and females to increases in the unit price (FR/unit dose) of nicotine (i.e., elasticity of demand or reinforcing efficacy). Females exhibited significantly higher baseline intake and less compensation than males. However, there were no sex differences in the reinforcement threshold or elasticity of demand. Dose-response relationships were very well described by the exponential demand function (r(2) values>0.96 for individual subjects). These findings suggest that females may exhibit less compensatory smoking in response to nicotine reduction policies, even though their nicotine reinforcement threshold and elasticity of demand may not differ from males

  2. The antiapoptotic effects of different doses of β-carotene in chronic ethanol-fed rats

    PubMed Central

    Peng, Hsiang-Chi; Chen, Ya-Ling; Yang, Shin-Yi; Ho, Pei-Yin; Yang, Sien-Sing

    2013-01-01

    Background Ethanol consumption might induce hepatic apoptosis and cause liver damage. The study was to investigate the effects of different doses of β-carotene supplementation on the antioxidant capacity and hepatic apoptosis in chronic ethanol-fed rats. Methods Rats were divided into 6 groups: C (control liquid diet), CLB [control liquid diet with β-carotene supplementation at 0.52 mg/kg body weight (BW)/day], CHB (control liquid diet with β-carotene supplementation at 2.6 mg/kg BW/day), E (ethanol liquid diet), ELB (ethanol liquid diet with β-carotene supplementation at 0.52 mg/kg BW/day), and EHB (ethanol liquid diet with β-carotene supplementation at 2.6 mg/kg BW/day). After 12 weeks, rats were sacrificed and blood and liver samples were collected for analysis. Results Lipid peroxidation and hepatic cytochrome P450 2E1 (CYP2E1) expression had increased, and hepatic Fas ligand, caspase-8, cytochrome c, caspase-9, and -3 expressions had significantly increased in the E group. However, lipid peroxidation and CYP2E1, caspase-9, and -3 expressions were significantly lower and Bcl-xL expression was higher in the ELB group. The hepatic tumor necrosis factor (TNF)-α level, lipid peroxidation, and cytochrome c expression were significantly lower and Bcl-2 expression was significantly higher in the EHB group. Conclusions The results suggest that ethanol treatment causes oxidative stress and hepatic apoptosis leading to liver injury, and β-carotene supplementation (0.52 mg/kg BW/day) can prevent ethanol-induced liver damage by decreasing ethanol-induced oxidative stress and inhibiting apoptosis in the liver. PMID:24570931

  3. Automatic image registration performance for two different CBCT systems; variation with imaging dose

    NASA Astrophysics Data System (ADS)

    Barber, J.; Sykes, J. R.; Holloway, L.; Thwaites, D. I.

    2014-03-01

    The performance of an automatic image registration algorithm was compared on image sets collected with two commercial CBCT systems, and the relationship with imaging dose was explored. CBCT images of a CIRS Virtually Human Male Pelvis phantom (VHMP) were collected on Varian TrueBeam/OBI and Elekta Synergy/XVI linear accelerators, across a range of mAs settings. Each CBCT image was registered 100 times, with random initial offsets introduced. Image registration was performed using the grey value correlation ratio algorithm in the Elekta XVI software, to a mask of the prostate volume with 5 mm expansion. Residual registration errors were calculated after correcting for the initial introduced phantom set-up error. Registration performance with the OBI images was similar to that of XVI. There was a clear dependence on imaging dose for the XVI images with residual errors increasing below 4mGy. It was not possible to acquire images with doses lower than ~5mGy with the OBI system and no evidence of reduced performance was observed at this dose. Registration failures (maximum target registration error > 3.6 mm on the surface of a 30mm sphere) occurred in 5% to 9% of registrations except for the lowest dose XVI scan (31%). The uncertainty in automatic image registration with both OBI and XVI images was found to be adequate for clinical use within a normal range of acquisition settings.

  4. Determination of gelation doses of gamma-irradiated hydrophilic polymers by different methods

    NASA Astrophysics Data System (ADS)

    Yiǧit, Fatma; Tekin, Niket; Erkan, Sevin; Güven, Olgun

    1994-04-01

    Poly(acrylic acid) and poly(vinyl pyrrolidone) are hydrophilic polymers. Poly(acrylic acid) is a polyelectrolyte which ionizes in water to produce an electrically conducting medium. Therefore, the gelation dose of poly(acrylic acid) can be determined by conductometric titration, simple titration and the measurement of pH. The conventional techniques of determining gelation dose are very time and material consuming especially for poly(acrylic acid) and subject to serious errors due to its electrolytic behavior. In this study, it has been shown that the gelation dose of poly(acrylic acid) can be determined by conductimetric and titrimetric methods with NaOH and measuring pH of aqueous solution of γ-irradiated polymer. In order to develop new, simpler and rapid methods for the determination of gelation dose of PVP, its complexation with gallic acid in dilute aqueous solution has been used. The complex formation between gallic acid and irradiated PVP in aqueous solutions is followed by UV-vis spectroscopy. The reliability of the dose value found, 120 kGy for poly(acrylic acid) and 140 kGy for poly(vinyl pyrrolidone), are also verified by viscometric and solubility measurements.

  5. Radiation-induced 1/f noise degradation of PNP bipolar junction transistors at different dose rates

    NASA Astrophysics Data System (ADS)

    Qi-Feng, Zhao; Yi-Qi, Zhuang; Jun-Lin, Bao; Wei, Hu

    2016-04-01

    It is found that ionizing-radiation can lead to the base current and the 1/f noise degradations in PNP bipolar junction transistors. In this paper, it is suggested that the surface of the space charge region of the emitter-base junction is the main source of the base surface 1/f noise. A model is developed which identifies the parameters and describes their interactive contributions to the recombination current at the surface of the space charge region. Based on the theory of carrier number fluctuation and the model of surface recombination current, a 1/f noise model is developed. This model suggests that 1/f noise degradations are the result of the accumulation of oxide-trapped charges and interface states. Combining models of ELDRS, this model can explain the reason why the 1/f noise degradation is more severe at a low dose rate than at a high dose rate. The radiations were performed in a Co60 source up to a total dose of 700 Gy(Si). The low dose rate was 0.001 Gy(Si)/s and the high dose rate was 0.1 Gy(Si)/s. The model accords well with the experimental results. Project supported by the National Natural Science Foundation of China (Grant Nos. 61076101 and 61204092).

  6. Model of radiation-induced gain degradation of NPN bipolar junction transistor at different dose rates

    NASA Astrophysics Data System (ADS)

    Qifeng, Zhao; Yiqi, Zhuang; Junlin, Bao; Wei, Hu

    2015-06-01

    Ionizing-radiation-induced current gain degradation in NPN bipolar junction transistors is due to an increase in base current as a result of recombination at the surface of the device. A model is presented which identifies the physical mechanism responsible for current gain degradation. The increase in surface recombination velocity due to interface states results in an increase in base current. Besides, changing the surface potential along the base surface induced by the oxide-trapped charges can also lead to an increased base current. By combining the production mechanisms of oxide-trapped charges and interface states, this model can explain the fact that the current gain degradation is more severe at a low dose rate than at a high dose rate. The radiations were performed in a Co60 source up to a total dose of 70 krad(Si). The low dose rate was 0.1 rad(Si)/s and the high dose rate was 10 rad(Si)/s. The model accords well with the experimental results. Project supported by the National Natural Science Foundation of China (Nos. 61076101, 61204092).

  7. Indoor terrestrial gamma dose rate mapping in France: a case study using two different geostatistical models.

    PubMed

    Warnery, E; Ielsch, G; Lajaunie, C; Cale, E; Wackernagel, H; Debayle, C; Guillevic, J

    2015-01-01

    Terrestrial gamma dose rates show important spatial variations in France. Previous studies resulted in maps of arithmetic means of indoor terrestrial gamma dose rates by "departement" (French district). However, numerous areas could not be characterized due to the lack of data. The aim of our work was to obtain more precise estimates of the spatial variability of indoor terrestrial gamma dose rates in France by using a more recent and complete data base and geostatistics. The study was based on the exploitation of 97,595 measurements results distributed in 17,404 locations covering all of France. Measurements were done by the Institute for Radioprotection and Nuclear Safety (IRSN) using RPL (Radio Photo Luminescent) dosimeters, exposed during several months between years 2011 and 2012 in French dentist surgeries and veterinary clinics. The data used came from dosimeters which were not exposed to anthropic sources. After removing the cosmic rays contribution in order to study only the telluric gamma radiation, it was decided to work with the arithmetic means of the time-series measurements, weighted by the time-exposure of the dosimeters, for each location. The values varied between 13 and 349 nSv/h, with an arithmetic mean of 76 nSv/h. The observed statistical distribution of the gamma dose rates was skewed to the right. Firstly, ordinary kriging was performed in order to predict the gamma dose rate on cells of 1*1 km(2), all over the domain. The second step of the study was to use an auxiliary variable in estimates. The IRSN achieved in 2010 a classification of the French geological formations, characterizing their uranium potential on the bases of geology and local measurement results of rocks uranium content. This information is georeferenced in a map at the scale 1:1,000,000. The geological uranium potential (GUP) was classified in 5 qualitative categories. As telluric gamma rays mostly come from the progenies of the (238)Uranium series present in rocks, this

  8. Dose conversion coefficients for monoenergetic electrons incident on a realistic human eye model with different lens cell populations.

    PubMed

    Nogueira, P; Zankl, M; Schlattl, H; Vaz, P

    2011-11-01

    The radiation-induced posterior subcapsular cataract has long been generally accepted to be a deterministic effect that does not occur at doses below a threshold of at least 2 Gy. Recent epidemiological studies indicate that the threshold for cataract induction may be much lower or that there may be no threshold at all. A thorough study of this subject requires more accurate dose estimates for the eye lens than those available in ICRP Publication 74. Eye lens absorbed dose per unit fluence conversion coefficients for electron irradiation were calculated using a geometrical model of the eye that takes into account different cell populations of the lens epithelium, together with the MCNPX Monte Carlo radiation transport code package. For the cell population most sensitive to ionizing radiation-the germinative cells-absorbed dose per unit fluence conversion coefficients were determined that are up to a factor of 4.8 higher than the mean eye lens absorbed dose conversion coefficients for electron energies below 2 MeV. Comparison of the results with previously published values for a slightly different eye model showed generally good agreement for all electron energies. Finally, the influence of individual anatomical variability was quantified by positioning the lens at various depths below the cornea. A depth difference of 2 mm between the shallowest and the deepest location of the germinative zone can lead to a difference between the resulting absorbed doses of up to nearly a factor of 5000 for electron energy of 0.7 MeV. PMID:21983644

  9. Development of a graphite probe calorimeter for absolute clinical dosimetry.

    PubMed

    Renaud, James; Marchington, David; Seuntjens, Jan; Sarfehnia, Arman

    2013-02-01

    The aim of this work is to present the numerical design optimization, construction, and experimental proof of concept of a graphite probe calorimeter (GPC) conceived for dose measurement in the clinical environment (U.S. provisional patent 61∕652,540). A finite element method (FEM) based numerical heat transfer study was conducted using a commercial software package to explore the feasibility of the GPC and to optimize the shape, dimensions, and materials used in its design. A functioning prototype was constructed inhouse and used to perform dose to water measurements under a 6 MV photon beam at 400 and 1000 MU∕min, in a thermally insulated water phantom. Heat loss correction factors were determined using FEM analysis while the radiation field perturbation and the graphite to water absorbed dose conversion factors were calculated using Monte Carlo simulations. The difference in the average measured dose to water for the 400 and 1000 MU∕min runs using the TG-51 protocol and the GPC was 0.2% and 1.2%, respectively. Heat loss correction factors ranged from 1.001 to 1.002, while the product of the perturbation and dose conversion factors was calculated to be 1.130. The combined relative uncertainty was estimated to be 1.4%, with the largest contributors being the specific heat capacity of the graphite (type B, 0.8%) and the reproducibility, defined as the standard deviation of the mean measured dose (type A, 0.6%). By establishing the feasibility of using the GPC as a practical clinical absolute photon dosimeter, this work lays the foundation for further device enhancements, including the development of an isothermal mode of operation and an overall miniaturization, making it potentially suitable for use in small and composite radiation fields. It is anticipated that, through the incorporation of isothermal stabilization provided by temperature controllers, a subpercent overall uncertainty will be achieved.

  10. Development of a graphite probe calorimeter for absolute clinical dosimetry

    SciTech Connect

    Renaud, James; Seuntjens, Jan; Sarfehnia, Arman; Marchington, David

    2013-02-15

    The aim of this work is to present the numerical design optimization, construction, and experimental proof of concept of a graphite probe calorimeter (GPC) conceived for dose measurement in the clinical environment (U.S. provisional patent 61/652,540). A finite element method (FEM) based numerical heat transfer study was conducted using a commercial software package to explore the feasibility of the GPC and to optimize the shape, dimensions, and materials used in its design. A functioning prototype was constructed inhouse and used to perform dose to water measurements under a 6 MV photon beam at 400 and 1000 MU/min, in a thermally insulated water phantom. Heat loss correction factors were determined using FEM analysis while the radiation field perturbation and the graphite to water absorbed dose conversion factors were calculated using Monte Carlo simulations. The difference in the average measured dose to water for the 400 and 1000 MU/min runs using the TG-51 protocol and the GPC was 0.2% and 1.2%, respectively. Heat loss correction factors ranged from 1.001 to 1.002, while the product of the perturbation and dose conversion factors was calculated to be 1.130. The combined relative uncertainty was estimated to be 1.4%, with the largest contributors being the specific heat capacity of the graphite (type B, 0.8%) and the reproducibility, defined as the standard deviation of the mean measured dose (type A, 0.6%). By establishing the feasibility of using the GPC as a practical clinical absolute photon dosimeter, this work lays the foundation for further device enhancements, including the development of an isothermal mode of operation and an overall miniaturization, making it potentially suitable for use in small and composite radiation fields. It is anticipated that, through the incorporation of isothermal stabilization provided by temperature controllers, a subpercent overall uncertainty will be achieved.

  11. Effects of Different Doses of Levetiracetam on Aquaporin 4 Expression in Rats with Brain Edema Following Fluid Percussion Injury.

    PubMed

    Jin, Hongbo; Li, Wenling; Dong, Changzheng; Ma, Li; Wu, Jiang; Zhao, Wenqing

    2016-01-01

    BACKGROUND This study was designed to investigate the effects of different doses of levetiracetam on aquaporin 4 (AQP4) expression in rats after fluid percussion injury. MATERIAL AND METHODS Sprague-Dawley rats were randomly divided into 4 groups: sham operation group, traumatic brain injury group, low-dose levetiracetam group, and high-dose levetiracetam group. Brain edema models were established by fluid percussion injury, and intervened by the administration of levetiracetam. Samples from the 4 groups were collected at 2, 6, 12, and 24 h, and at 3 and 7 days after injury. Histological observation was performed using hematoxylin-eosin staining and immunohistochemical staining. AQP4 and AQP4 mRNA expression was detected using Western blot assay and RT-PCR. Brain water content was measured by the dry-wet method. RESULTS Compared with the traumatic brain injury group, brain water content, AQP4 expression, and AQP4 mRNA expression were lower in the levetiracetam groups at each time point and the differences were statistically significant (P<0.05). The intervention effects of high-dose levetiracetam were more apparent. CONCLUSIONS Levetiracetam can lessen brain edema from fluid percussion injury by down-regulating AQP4 and AQP4 mRNA expression. There is a dose-effect relationship in the preventive effect of levetiracetam within a certain extent. PMID:26927633

  12. Effects of Different Doses of Levetiracetam on Aquaporin 4 Expression in Rats with Brain Edema Following Fluid Percussion Injury

    PubMed Central

    Jin, Hongbo; Li, Wenling; Dong, Changzheng; Ma, Li; Wu, Jiang; Zhao, Wenqing

    2016-01-01

    Background This study was designed to investigate the effects of different doses of levetiracetam on aquaporin 4 (AQP4) expression in rats after fluid percussion injury. Material/Methods Sprague-Dawley rats were randomly divided into 4 groups: sham operation group, traumatic brain injury group, low-dose levetiracetam group, and high-dose levetiracetam group. Brain edema models were established by fluid percussion injury, and intervened by the administration of levetiracetam. Samples from the 4 groups were collected at 2, 6, 12, and 24 h, and at 3 and 7 days after injury. Histological observation was performed using hematoxylin-eosin staining and immunohistochemical staining. AQP4 and AQP4 mRNA expression was detected using Western blot assay and RT-PCR. Brain water content was measured by the dry-wet method. Results Compared with the traumatic brain injury group, brain water content, AQP4 expression, and AQP4 mRNA expression were lower in the levetiracetam groups at each time point and the differences were statistically significant (P<0.05). The intervention effects of high-dose levetiracetam were more apparent. Conclusions Levetiracetam can lessen brain edema from fluid percussion injury by down-regulating AQP4 and AQP4 mRNA expression. There is a dose-effect relationship in the preventive effect of levetiracetam within a certain extent. PMID:26927633

  13. [Retrospective Cytogenetic Dose Evaluation. II. Computer Data Processing in Persons Irradiated in Different Radiation Accidents].

    PubMed

    Nugis, V Yu; Khvostunov, I K; Goloub, E V; Kozlova, M G; Nadejinal, N M; Galstian, I A

    2015-01-01

    The method for retrospective dose assessment based on the analysis of cell distribution by the number of dicentrics and unstable aberrations using a special computer program was earlier developed based on the data about the persons irradiated as a result of the accident at the Chernobyl nuclear power plant. This method was applied for the same purpose for data processing of repeated cytogenetic studies of the patients exposed to γ-, γ-β- or γ-neutron radiation in various situations. As a whole, this group was followed up in more distant periods (17-50 years) after exposure than Chernobyl patients (up to 25 years). The use for retrospective dose assessment of the multiple regression equations obtained for the Chernobyl cohort showed that the equation, which includes computer recovered estimate of the dose and the time elapsed after irradiation, was generally unsatisfactory (r = 0.069 at p = 0.599). Similar equations with recovered estimate of the dose and frequency of abnormal chromosomes in a distant period or with all three parameters as variables gave better results (r = 0.686 at p = 0.000000001 and r = 0.542 at p = 0.000008, respectively). PMID:26863777

  14. Effect of different doses of coated butyric acid on growth performance and energy utilization in broilers.

    PubMed

    Kaczmarek, S A; Barri, A; Hejdysz, M; Rutkowski, A

    2016-04-01

    We recently applied four dietary treatments in experiments I and II to determine the effect of protected calcium butyrate (BP) on growth performance and nutrient digestibility in broiler chickens. A group of one-day-old male Ross 308 broiler chicks (total 960, 480 per trial) were used in the study. In experiment I, the basal diets were fed with protected BP inclusion (0.2, 0.3, or 0.4 g/kg of finished feed) (BP) or without (C). In experiment II, 4 different diets were tested: 1) basal diet with no supplementation (C), 2) basal diet supplemented with protected BP (0.3 g/kg) (BP), 3) basal diet supplemented with avilamycin (6 mg/kg, active substance) a common antibiotic growth promoter (AGP) (Av), and 4) basal diet supplemented with the combination of both avilaymicin and BP. In experiment I, considering the entire study period, the use of BP improved feed conversion ratio (P<0.05) irrespective of the dose. Apparent total tract crude fat digestibility and apparent metabolizable energy corrected for nitrogen (AMEN) were improved after BP supplementation (P<0.05). In experiment II, A or AB diets improved (P<0.05) body weight gain compared to the control treatment. The diets Av, BP, and AvB improved (P<0.05) feed conversion ratio compared to the control treatment. Birds from the treatment diet were characterized by having the thickest mucosa (P<0.05). On days 14, 35, and 42, the use of AB diets improved AMENcontent compared to the control treatment (P<0.05). The apparent ileal digestibility of amino acid data showed that Av or AvB treated birds were characterized by higher Asp, Glu, Cys, Gly, and Ala ileal digestibility than the control animals (P<0.05). The use of Av, BP, or AvB increased ileal digestibility of Thr, Ser, and Pro (P<0.05). There is an indication that BP, alone or in combination with avilamycin, improve the digestion and absorptive processes and consequently birds performance results. PMID:26740137

  15. Absolute Identification by Relative Judgment

    ERIC Educational Resources Information Center

    Stewart, Neil; Brown, Gordon D. A.; Chater, Nick

    2005-01-01

    In unidimensional absolute identification tasks, participants identify stimuli that vary along a single dimension. Performance is surprisingly poor compared with discrimination of the same stimuli. Existing models assume that identification is achieved using long-term representations of absolute magnitudes. The authors propose an alternative…

  16. Be Resolute about Absolute Value

    ERIC Educational Resources Information Center

    Kidd, Margaret L.

    2007-01-01

    This article explores how conceptualization of absolute value can start long before it is introduced. The manner in which absolute value is introduced to students in middle school has far-reaching consequences for their future mathematical understanding. It begins to lay the foundation for students' understanding of algebra, which can change…

  17. Clinical research on erythrocyte deformability with different doses of He-Ne exposure in patient with ischemia disease

    NASA Astrophysics Data System (ADS)

    Zhao, Yanping; Liu, Song-hao; Sun, Jinbo; Luo, Gangyue; Hua, Rong; Liu, Qianqin

    2005-01-01

    The aim of this study was to test human erythrocyte deformability with the exposure of erythrocyte from apoplexy patient and other ischemia diseases, contracted with normal donors' blood sample, and the doses-effect of Low-power He_Ne laser in vitro were discussed. Fresh blood sample from adult health donors and patients with different diseases such as apoplexy, diabetes, heart block etc in emergency department were collected and divided into different groups in which there were no less than 6 persons. Fresh human blood samples were irradiated with a He-Ne laser (Lamba=632.8nm), power output around 4.5MW, 9MW, 15mW, and 18mW, et al., exposure time from 7.5min, 15min, and 30min, operating in continuous wave. Measurements of human erythrocyte deformability were taken. Erythrocyte deformability appearance shown some different in the health contracted group and the other ischemia disease group. Some notice difference also shown among some disease group with nonirradiation and the same disease group with laser irradiation. The dose-effects of He-Ne laser therapy was discussed on the further research on the erythrocyte deformability of blood sample from patients with apoplexy disease treated with He-Ne laser at different doses, and a certain optimal doses which could take a beneficial effect in clinic were speculated on. This study revealed that the He-Ne laser have some different effects on erythrocyte deformability in vitro, which were related with the disease condition, red cell state, and outpower-doses, et al closely.

  18. Sex differences in nicotine self-administration in rats during progressive unit dose reduction: Implications for nicotine regulation policy

    PubMed Central

    Grebenstein, Patricia; Burroughs, Danielle; Zhang, Yan; LeSage, Mark G.

    2013-01-01

    Reducing the nicotine content in tobacco products is being considered by the FDA as a policy to reduce the addictiveness of tobacco products. Understanding individual differences in response to nicotine reduction will be critical to developing safe and effective policy. Animal and human research demonstrating sex differences in the reinforcing effects of nicotine suggests that males and females may respond differently to nicotine-reduction policies. However, no studies have directly examined sex differences in the effects of nicotine unit-dose reduction on nicotine self-administration (NSA) in animals. The purpose of the present study was to examine this issue in a rodent self-administration model. Male and female rats were trained to self-administer nicotine (0.06 mg/kg) under an FR 3 schedule during daily 23 h sessions. Rats were then exposed to saline extinction and reacquisition of NSA, followed by weekly reductions in the unit dose (0.03 to 0.00025 mg/kg) until extinction levels of responding were achieved. Males and females were compared with respect to baseline levels of intake, resistance to extinction, degree of compensatory increases in responding during dose reduction, and the threshold reinforcing unit dose of nicotine. Exponential demand-curve analysis was also conducted to compare the sensitivity of males and females to increases in the unit price (FR/unit dose) of nicotine (i.e., elasticity of demand or reinforcing efficacy). Females exhibited significantly higher baseline intake and less compensation than males. However, there were no sex differences in the reinforcement threshold or elasticity of demand. Dose–response relationships were very well described by the exponential demand function (r2 values > 0.96 for individual subjects). These findings suggest that females may exhibit less compensatory smoking in response to nicotine reduction policies, even though their nicotine reinforcement threshold and elasticity of demand may not differ from

  19. Different doses of prophylactic platelet transfusion for preventing bleeding in patients with haematological disorders after chemotherapy or stem cell transplantation

    PubMed Central

    Estcourt, Lise J; Stanworth, Simon; Doree, Carolyn; Trivella, Marialena; Hopewell, Sally; Murphy, Michael F; Tinmouth, Alan

    2014-01-01

    This is the protocol for a review and there is no abstract. The objectives are as follows: To determine whether different doses of prophylactic platelet transfusions (platelet transfusions given to prevent bleeding) affect their efficacy and safety in preventing bleeding in patients with haematological disorders after chemotherapy with or without stem cell transplantation. PMID:25722652

  20. Influence of two different doses of infectious bovine rhinotracheitis virus (IBRV) on immune and physiological parameters in steers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To evaluate the effects different doses of IBRV and the impact they have on immunological and physiological parameters of cattle, 18 Holstein steers (450.11 ± 75.70 kg) were randomly assigned to either a control group or 1 of 2 IBRV challenged groups. Prior to the challenge, steers were fitted with ...

  1. Comparing Two Different Doses of Intravenous Midazolam in Pediatric Sedation and Analgesia

    PubMed Central

    Barzegari, Hassan; Masoumi, Kambiz; Motamed, Hassan; Zohrevandi, Behzad; Zeynadini Meymand, Shima

    2016-01-01

    Introduction: Midazolam has turned into a common drug for pediatric procedural sedation and analgesia. However, there is not much data regarding its proper dose and potential side effects in the Iranian children population. Therefore, the present study was done to compare 2 doses of IV midazolam in this regard. Methods: The present clinical trial was performed to compare 0.1 and 0.3 mg/kg doses of IV midazolam in induction of sedation for head trauma infant patients in need of brain computed tomography (CT) scan. Conscious infants under 2 years old, with stable hemodynamics were included. Onset and duration of action as well as probable side effects were compared between the two groups using SPSS version 22. Results: 110 infants with the mean age of 14.0 ± 5.9 months (range: 4 - 24) and mean weight of 9.7 ± 2 kg (range: 5 - 15) were randomly allocated to one of the 2 study groups (54.6% female). Success rate in 0.1 and 0.3 mg/kg groups were 38.2% (21 patients) and 60% (33 patients), respectively (p = 0.018). Overall, 56 (50.9%) patients did not reach proper sedation and were sedated receiving ketamine (22 patients) or another dose of midazolam (34 patients, mean additional dose needed was 2.1 ± 1.1 mg). Conclusion: The results of the present study demonstrated the higher success rate and longer duration of action for 0.3 mg/kg midazolam compared to 0.1 mg/kg. The groups were equal regarding onset of action, effect on vital signs and probable side effects. PMID:27800539

  2. The absolute disparity anomaly and the mechanism of relative disparities.

    PubMed

    Chopin, Adrien; Levi, Dennis; Knill, David; Bavelier, Daphne

    2016-06-01

    There has been a long-standing debate about the mechanisms underlying the perception of stereoscopic depth and the computation of the relative disparities that it relies on. Relative disparities between visual objects could be computed in two ways: (a) using the difference in the object's absolute disparities (Hypothesis 1) or (b) using relative disparities based on the differences in the monocular separations between objects (Hypothesis 2). To differentiate between these hypotheses, we measured stereoscopic discrimination thresholds for lines with different absolute and relative disparities. Participants were asked to judge the depth of two lines presented at the same distance from the fixation plane (absolute disparity) or the depth between two lines presented at different distances (relative disparity). We used a single stimulus method involving a unique memory component for both conditions, and no extraneous references were available. We also measured vergence noise using Nonius lines. Stereo thresholds were substantially worse for absolute disparities than for relative disparities, and the difference could not be explained by vergence noise. We attribute this difference to an absence of conscious readout of absolute disparities, termed the absolute disparity anomaly. We further show that the pattern of correlations between vergence noise and absolute and relative disparity acuities can be explained jointly by the existence of the absolute disparity anomaly and by the assumption that relative disparity information is computed from absolute disparities (Hypothesis 1).

  3. The absolute disparity anomaly and the mechanism of relative disparities

    PubMed Central

    Chopin, Adrien; Levi, Dennis; Knill, David; Bavelier, Daphne

    2016-01-01

    There has been a long-standing debate about the mechanisms underlying the perception of stereoscopic depth and the computation of the relative disparities that it relies on. Relative disparities between visual objects could be computed in two ways: (a) using the difference in the object's absolute disparities (Hypothesis 1) or (b) using relative disparities based on the differences in the monocular separations between objects (Hypothesis 2). To differentiate between these hypotheses, we measured stereoscopic discrimination thresholds for lines with different absolute and relative disparities. Participants were asked to judge the depth of two lines presented at the same distance from the fixation plane (absolute disparity) or the depth between two lines presented at different distances (relative disparity). We used a single stimulus method involving a unique memory component for both conditions, and no extraneous references were available. We also measured vergence noise using Nonius lines. Stereo thresholds were substantially worse for absolute disparities than for relative disparities, and the difference could not be explained by vergence noise. We attribute this difference to an absence of conscious readout of absolute disparities, termed the absolute disparity anomaly. We further show that the pattern of correlations between vergence noise and absolute and relative disparity acuities can be explained jointly by the existence of the absolute disparity anomaly and by the assumption that relative disparity information is computed from absolute disparities (Hypothesis 1). PMID:27248566

  4. Effect of different phenylephrine bolus doses for treatment of hypotension during spinal anaesthesia in patients undergoing elective caesarean section.

    PubMed

    Mohta, M; Harisinghani, P; Sethi, A K; Agarwal, D

    2015-01-01

    The efficacy of phenylephrine might be improved by giving doses higher than that traditionally used (100 µg). This study compared the effects of three initial bolus doses of intravenous phenylephrine; 100 µg (group P100), 125 µg (group P125) and 150 µg (group P150), for the treatment of post-spinal hypotension in patients undergoing elective caesarean delivery. If hypotension was not corrected by this dose, additional boluses of 25 µg were given every minute. Further hypotensive episodes were treated with half the initial bolus dose, followed by 25 µg boluses, as required. Umbilical arterial and venous blood samples were obtained for blood gas analysis and Apgar scores recorded. One hundred and twenty subjects (40 per group) who developed post-spinal hypotension (75%) were included in this randomised, double blind trial. Although systolic blood pressure was higher at certain time-points after 150 µg phenylephrine, there were no statistically significant differences in the effectiveness of the first bolus of phenylephrine to treat hypotension (85%, 95% and 95% in groups P100, P125 and P150, respectively, P=0.215); the additional dose of phenylephrine after the first bolus (P=0.810); the number of additional boluses (P=0.318) or of hypotensive episodes (P=0.118). There were no significant differences in the number of patients developing reactive hypertension or bradycardia, in maternal side-effects or in neonatal outcomes. Although the study may have been underpowered, initial phenylephrine bolus doses of 100 µg, 125 µg and 150 µg did not significantly differ in efficacy to treat post-spinal hypotension in these patients.

  5. Absolute Measurements of Radiation Damage in Nanometer Thick Films

    PubMed Central

    Alizadeh, Elahe; Sanche, Léon

    2013-01-01

    We address the problem of absolute measurements of radiation damage in films of nanometer thicknesses. Thin films of DNA (~ 2–160nm) are deposited onto glass substrates and irradiated with varying doses of 1.5 keV X-rays under dry N2 at atmospheric pressure and room temperature. For each different thickness, the damage is assessed by measuring the loss of the supercoiled configuration as a function of incident photon fluence. From the exposure curves, the G-values are deduced, assuming that X-ray photons interacting with DNA, deposit all of their energy in the film. The results show that the G-value (i.e., damage per unit of deposited energy) increases with film thickness and reaches a plateau at 30±5 nm. This thickness dependence provides a correction factor to estimate the actual G-value for films with thicknesses below 30nm thickness. Thus, the absolute values of damage can be compared with that of films of any thickness under different experimental conditions. PMID:22562941

  6. Dosimetric verification of surface and superficial doses for head and neck IMRT with different PTV shrinkage margins

    SciTech Connect

    Shiau, An-Cheng; Lai, Pei-Ling; Liang, Ji-An; and others

    2011-03-15

    Purpose: Dosimetric uncertainty in the surface and superficial regions is still a major concern for radiation therapy and becomes more important when using the inverse planning algorithm for IMRT. The purpose of this study was to measure dose distributions and to evaluate the calculation accuracy in the superficial region for different planning target volume (PTV) shrinkage methods for head and neck IMRT plans. Methods: A spherical polystyrene phantom 160 mm in diameter (ball phantom) was used to simulate the shape of the head. Strips of superflab bolus with thicknesses of 3.5 and 7.0 mm were spread on the surface of the ball phantom. Three sets of CT images were acquired for the ball phantom without and with the bolus. The hypothetical clinical target volume (CTV) and critical structures (spinal cord and parotid glands) were outlined on each set of CT images. The PTVs were initially created by expanding an isotropic 3 mm margin from the CTV and then margins of 0, 3, and 5 mm were shrunk from the phantom surface for dosimetric analysis. Seven-field IMRT plans with a prescribed dose of 180 cGy and same dose constraints were designed using an Eclipse treatment planning system. Superficial doses at depths of 0, 3.5, and 7.0 mm and at seven beam axis positions (gantry angles of 0 deg., 30 deg., 60 deg., 80 deg., 330 deg., 300 deg., and 280 deg.) were measured for each PTV shrinkage margin using 0.1 mm ultrathin thermoluminescent dosimeters. For each plan, the measured doses were compared to the calculated doses. Results: The PTV without shrinkage had the highest intensity and the steepest dose gradient in the superficial region. The mean measured doses for different positions at depths of 0, 3.5, and 7.0 mm were 106{+-}18, 185{+-}16, and 188{+-}12 cGy, respectively. For a PTV with 3 mm shrinkage, the mean measured doses were 94{+-}13, 183{+-}8, and 191{+-}8 cGy. For a PTV with 5 mm shrinkage, the mean measured doses were 86{+-}11, 173{+-}8, and 187{+-}5 cGy. The

  7. Increased beam attenuation and surface dose by different couch inserts of treatment tables used in megavoltage radiotherapy.

    PubMed

    Seppälä, Jan K H; Kulmala, Jarmo A J

    2011-11-15

    The use of solid carbon fiber table materials in radiotherapy has become more common with the implementation of image-guided radiotherapy (IGRT), since the solid materials give less imaging artifacts than the so-called tennis racket couchtops. The downside of the solid carbon fiber couch inserts is that they increase the beam attenuation, resulting in increased surface doses and inaccuracies in determine the dose in the patient. The purpose of this study was to evaluate the interaction of 6 and 15 MV photons with eight different couch inserts. The presented results enable direct comparison of the attenuation properties of the studied couchtops. With a direct posterior beam the maximum attenuations reach 3.6% and 2.4% with 6 and 15 MV, respectively. The measured maximum attenuation by a couchtop with an oblique gantry angle was 10.8% and 7.4% at 6 and 15 MV energies, respectively. The skin-sparing effect was decreased substantially with every couchtop. The highest increases in surface doses were recorded to be four- and threefold, as compared to the direct posterior open field surface doses of 6 and 15 MV, respectively. In conclusion, the carbon fiber tabletops decrease the skin-sparing effect of megavoltage photon energies. The increased beam attenuation and skin doses should be taken into account in the process of treatment planning.

  8. Comparison of the efficacy and safety of different doses of propacetamol for postoperative pain control after breast surgery.

    PubMed

    Kang, Joo-Eun; Park, Sun-Kyung; Song, In-Kyung; Lee, Ji-Hyun; Kim, Jin-Tae; Kim, Hee-Soo

    2015-06-01

    Intravenous propacetamol has been shown to be effective for postoperative pain control. However, the recommendations regarding propacetamol doses for pain control are vague. The present study was performed to compare the efficacy and safety of propacetamol at a dose of 1 g or 2 g. After breast-conserving surgery, patients received 1 g or 2 g intravenous propacetamol. Treatment efficacy for pain control was assessed using a 100 mm visual analog scale at 15, 30, 45, and 60 minutes and 4 hours after surgery, and global evaluation was assessed by a 4-point categorical scale at the end of the 4-hour study period. Safety was monitored through adverse event reporting. Patients were allowed rescue analgesia, and the timing of requests was recorded. A total of 111 patients were enrolled in the study. There were no differences in efficacy variables, including visual analog scale, the 4-point categorical scale, and requests for rescue analgesia, between propacetamol doses of 1 g and 2 g. Adverse events were similar in the two groups. Intravenous propacetamol at a dose of 2 g is not superior to the lower dose of 1 g with regard to postoperative analgesia or the incidence of side effects in breast-conserving surgery. PMID:26025796

  9. Influence of seed extract of Syzygium Cumini (Jamun) on mice exposed to different doses of gamma-radiation.

    PubMed

    Jagetia, Ganesh Chandra; Baliga, Manjeshwar Shrinath; Venkatesh, Ponemone

    2005-03-01

    The radioprotective activity of the hydroalcoholic extract of jamun seeds (SCE) was studied in mice exposed to different doses of gamma radiation. The mice were injected with 0, 5, 10, 20, 40, 60, 80, 100, 120, 140 or 160 mg/kg body weight of SCE, before exposure to 10 Gy of gamma radiation, to select the optimum dose of radiation protection. The 80 mg/kg SCE was found to offer highest protection, therefore, further studies were carried out using this dose. The drug was more effective when administered through the intraperitoneal route at equimolar doses than the oral route. Since higher survival was observed for the i.p. route (50%), than the oral route (29.2%), all other studies were carried out by injecting SCE intraperitoneally. The mice treated with 80 mg/kg body weight SCE intraperitoneally before exposure to 6, 7, 8, 9, 10 and 11 Gy of gamma radiation showed reduction in the symptoms of radiation sickness and mortality at all exposure doses and caused a significant increase in the animal survival when compared with the concurrent double distilled water (DDW) + irradiation group. The SCE treatment protected mice against the gastrointestinal as well as bone marrow deaths and the DRF was found to be 1.24. PMID:15802860

  10. Combined Use of Absolute and Differential Seismic Arrival Time Data to Improve Absolute Event Location

    NASA Astrophysics Data System (ADS)

    Myers, S.; Johannesson, G.

    2012-12-01

    Arrival time measurements based on waveform cross correlation are becoming more common as advanced signal processing methods are applied to seismic data archives and real-time data streams. Waveform correlation can precisely measure the time difference between the arrival of two phases, and differential time data can be used to constrain relative location of events. Absolute locations are needed for many applications, which generally requires the use of absolute time data. Current methods for measuring absolute time data are approximately two orders of magnitude less precise than differential time measurements. To exploit the strengths of both absolute and differential time data, we extend our multiple-event location method Bayesloc, which previously used absolute time data only, to include the use of differential time measurements that are based on waveform cross correlation. Fundamentally, Bayesloc is a formulation of the joint probability over all parameters comprising the multiple event location system. The Markov-Chain Monte Carlo method is used to sample from the joint probability distribution given arrival data sets. The differential time component of Bayesloc includes scaling a stochastic estimate of differential time measurement precision based the waveform correlation coefficient for each datum. For a regional-distance synthetic data set with absolute and differential time measurement error of 0.25 seconds and 0.01 second, respectively, epicenter location accuracy is improved from and average of 1.05 km when solely absolute time data are used to 0.28 km when absolute and differential time data are used jointly (73% improvement). The improvement in absolute location accuracy is the result of conditionally limiting absolute location probability regions based on the precise relative position with respect to neighboring events. Bayesloc estimates of data precision are found to be accurate for the synthetic test, with absolute and differential time measurement

  11. [Genetic changes in yeast cells Saccharomyces irradiated by fast neutrons with different dose rate].

    PubMed

    Malinova, I V; Tsyb, T S; Komarova, E V

    2009-01-01

    No neutron dose rate effects in the wide range of 10(-3) Gy/s to 10(6) Gy/s were observed in yeast diploid cells for induction of mitotic segregation and crossing-over. The RBE values for these effects were determined as doses ratio (Dgamma/D(n)) at maximum effects. The RBE were 2.2-1.9 for neutrons of the reactor BR-10 (E = = 0.85 MeV) and the pulse reactor BARS-6 (E = 1.44 MeV). The RBE values for genetic effects were 1.0 at the equal survival level for neutrons and gamma-rays 60Co.

  12. Humoral response to blastospores and mycelium in mice injected with different doses of Candida albicans.

    PubMed

    Mesón, O E; Valdez, J C; de Alderete, N G; Sirena, A; Perdigón, G

    1992-01-01

    An indirect immunofluorescence assay was carry out to determine the IgM and IgG antibody responses to yeast and mycelial forms of Candida albicans in mice injected with a 5 x 5(5) and 5 x 10(7) live cells suspensions. Prior adsorption of the serum samples with heat-killed blastospores enabled us to follow the specific antimycelial response which were detected considerably later than expected. Slow level of antibodies were obtained within an infection of 5 x 10(5) cell for both antibody classes and for yeast and mycelial forms. When a 5 x 10(7) cell dose was used for inoculation, maximum titers of antibodies to blastospores and mycelium in non-adsorbed sera appeared almost simultaneously (days 15 and 13, respectively). When serum samples from mice infected with the same dose were previously adsorbed with blastospores, the antimycelium antibodies for both types of Igs, were detected delayed during the infection course. In this case the higher titer for IgG appeared on day 33 and on day 23 for IgM. We suggest that the high titer obtained with the blastospore forms for the 5 x 10(7) cell dose may be due to a major immunogenicity of this forms, for to induce an immune response in the host, or that the delay in the antimycelium antibodies detection could be due to that a blastospore form is the predominant in the infection early stages. Implications of this fact for pathogenesis are discussed.

  13. Effects on lung stress of position and different doses of perfluorocarbon in a model of ARDS.

    PubMed

    López-Aguilar, Josefina; Lucangelo, Umberto; Albaiceta, Guillermo M; Nahum, Avi; Murias, Gastón; Cañizares, Rosario; Oliva, Joan Carles; Romero, Pablo V; Blanch, Lluís

    2015-05-01

    We determined whether the combination of low dose partial liquid ventilation (PLV) with perfluorocarbons (PFC) and prone positioning improved lung function while inducing minimal stress. Eighteen pigs with acute lung injury were assigned to conventional mechanical ventilation (CMV) or PLV (5 or 10 ml/kg of PFC). Positive end-expiratory pressure (PEEP) trials in supine and prone positions were performed. Data were analyzed by a multivariate polynomial regression model. The interplay between PLV and position depended on the PEEP level. In supine PLV dampened the stress induced by increased PEEP during the trial. The PFC dose of 5 ml/kg was more effective than the dose 10 ml/kg. This effect was not observed in prone. Oxygenation was significantly higher in prone than in supine position mainly at lower levels of PEEP. In conclusion, MV settings should take both gas exchange and stress/strain into account. When protective CMV fails, rescue strategies combining prone positioning and PLV with optimal PEEP should improve gas exchange with minimal stress.

  14. Long-term metabolic effects of different doses of niacin-bound chromium on Sprague-Dawley rats.

    PubMed

    Perricone, N V; Bagchi, D; Echard, B; Preuss, Harry G

    2010-05-01

    We simultaneously assessed benefits and risks of niacin-bound chromium (NBC) intake at varying doses over a prolonged period of time (>1.2 years) in male and female Sprague-Dawley (SD) rats. We performed the study in two phases. First, we followed 60 male and 60 female SD rats, each gender divided into six groups. Through day 150 (phase 1A), all SD rats received a high sucrose diet (30% w/w) with or without different concentrations of NBC. The male/female groups were: 1] control without NBC n = 10, 2] low NBC (2.8 ppm, n = 10), 3] medium NBC (8.7 ppm, n = 20), 4] high NBC (28.0 ppm, n = 20). Based on dosing, we refer to the three treatment groups as 1X, 3X, and 10X. During days 151-312 (phase 1B), NBC was removed from diets of one half of the 3X and 10X groups. These are referred to as 3X satellite and 10X satellite. In phase 2 (days 313-460), males from groups 1X, 3X, 10X, 3X satellite, and 10X satellite received the same 3X dose of NBC (8.7 ppm). The last two groups also ingested different doses of a formulation of natural products in addition to NBC. We examined blood pressure, the renin-angiotensin system (RAS), nitric oxide (NO), and insulin systems and inflammatory parameters. Results in male and female SD rats were comparable. NBC lowered systolic blood pressure (SBP) in a dose-dependent fashion; however, after 200 days, the SBP of the low dose group (1X) began to rise and returned to baseline control. After raising the dose of NBC to 3X, the SBP in the 1X group decreased significantly once more. When half the test rats (3X and 10X) were deprived of NBC, SBP rose gradually to control levels after 2 to 3 months. However, the SBP decreased significantly once more when each satellite group returned to the 3X dose. Special testing suggests that NBC at adequate dosing increases insulin sensitivity, lowers HbA1C, decreases activity of the RAS, at least in part, through ACE inhibition, enhances NO activity, and is without signs of toxicity. The addition of a

  15. Long-term metabolic effects of different doses of niacin-bound chromium on Sprague-Dawley rats.

    PubMed

    Perricone, N V; Bagchi, D; Echard, B; Preuss, Harry G

    2010-05-01

    We simultaneously assessed benefits and risks of niacin-bound chromium (NBC) intake at varying doses over a prolonged period of time (>1.2 years) in male and female Sprague-Dawley (SD) rats. We performed the study in two phases. First, we followed 60 male and 60 female SD rats, each gender divided into six groups. Through day 150 (phase 1A), all SD rats received a high sucrose diet (30% w/w) with or without different concentrations of NBC. The male/female groups were: 1] control without NBC n = 10, 2] low NBC (2.8 ppm, n = 10), 3] medium NBC (8.7 ppm, n = 20), 4] high NBC (28.0 ppm, n = 20). Based on dosing, we refer to the three treatment groups as 1X, 3X, and 10X. During days 151-312 (phase 1B), NBC was removed from diets of one half of the 3X and 10X groups. These are referred to as 3X satellite and 10X satellite. In phase 2 (days 313-460), males from groups 1X, 3X, 10X, 3X satellite, and 10X satellite received the same 3X dose of NBC (8.7 ppm). The last two groups also ingested different doses of a formulation of natural products in addition to NBC. We examined blood pressure, the renin-angiotensin system (RAS), nitric oxide (NO), and insulin systems and inflammatory parameters. Results in male and female SD rats were comparable. NBC lowered systolic blood pressure (SBP) in a dose-dependent fashion; however, after 200 days, the SBP of the low dose group (1X) began to rise and returned to baseline control. After raising the dose of NBC to 3X, the SBP in the 1X group decreased significantly once more. When half the test rats (3X and 10X) were deprived of NBC, SBP rose gradually to control levels after 2 to 3 months. However, the SBP decreased significantly once more when each satellite group returned to the 3X dose. Special testing suggests that NBC at adequate dosing increases insulin sensitivity, lowers HbA1C, decreases activity of the RAS, at least in part, through ACE inhibition, enhances NO activity, and is without signs of toxicity. The addition of a

  16. Humoral response to blastospores and mycelium in mice injected with different doses of Candida albicans.

    PubMed

    Mesón, O E; Valdez, J C; de Alderete, N G; Sirena, A; Perdigón, G

    1992-01-01

    An indirect immunofluorescence assay was carry out to determine the IgM and IgG antibody responses to yeast and mycelial forms of Candida albicans in mice injected with a 5 x 5(5) and 5 x 10(7) live cells suspensions. Prior adsorption of the serum samples with heat-killed blastospores enabled us to follow the specific antimycelial response which were detected considerably later than expected. Slow level of antibodies were obtained within an infection of 5 x 10(5) cell for both antibody classes and for yeast and mycelial forms. When a 5 x 10(7) cell dose was used for inoculation, maximum titers of antibodies to blastospores and mycelium in non-adsorbed sera appeared almost simultaneously (days 15 and 13, respectively). When serum samples from mice infected with the same dose were previously adsorbed with blastospores, the antimycelium antibodies for both types of Igs, were detected delayed during the infection course. In this case the higher titer for IgG appeared on day 33 and on day 23 for IgM. We suggest that the high titer obtained with the blastospore forms for the 5 x 10(7) cell dose may be due to a major immunogenicity of this forms, for to induce an immune response in the host, or that the delay in the antimycelium antibodies detection could be due to that a blastospore form is the predominant in the infection early stages. Implications of this fact for pathogenesis are discussed. PMID:1345309

  17. Influence of robust optimization in intensity-modulated proton therapy with different dose delivery techniques

    SciTech Connect

    Liu Wei; Li Yupeng; Li Xiaoqiang; Cao Wenhua; Zhang Xiaodong

    2012-06-15

    Purpose: The distal edge tracking (DET) technique in intensity-modulated proton therapy (IMPT) allows for high energy efficiency, fast and simple delivery, and simple inverse treatment planning; however, it is highly sensitive to uncertainties. In this study, the authors explored the application of DET in IMPT (IMPT-DET) and conducted robust optimization of IMPT-DET to see if the planning technique's sensitivity to uncertainties was reduced. They also compared conventional and robust optimization of IMPT-DET with three-dimensional IMPT (IMPT-3D) to gain understanding about how plan robustness is achieved. Methods: They compared the robustness of IMPT-DET and IMPT-3D plans to uncertainties by analyzing plans created for a typical prostate cancer case and a base of skull (BOS) cancer case (using data for patients who had undergone proton therapy at our institution). Spots with the highest and second highest energy layers were chosen so that the Bragg peak would be at the distal edge of the targets in IMPT-DET using 36 equally spaced angle beams; in IMPT-3D, 3 beams with angles chosen by a beam angle optimization algorithm were planned. Dose contributions for a number of range and setup uncertainties were calculated, and a worst-case robust optimization was performed. A robust quantification technique was used to evaluate the plans' sensitivity to uncertainties. Results: With no uncertainties considered, the DET is less robust to uncertainties than is the 3D method but offers better normal tissue protection. With robust optimization to account for range and setup uncertainties, robust optimization can improve the robustness of IMPT plans to uncertainties; however, our findings show the extent of improvement varies. Conclusions: IMPT's sensitivity to uncertainties can be improved by using robust optimization. They found two possible mechanisms that made improvements possible: (1) a localized single-field uniform dose distribution (LSFUD) mechanism, in which the

  18. SU-E-T-227: Least Restrictive Assignment of Dose-Distance Differences (LRAD) in IMRT On a Conventional Linac

    SciTech Connect

    Dong, P; Faddegon, B

    2014-06-01

    Purpose: To develop a method to compare dose distributions based on the least restrictive of dose and distance differences, and to evaluate the method for IMRT QA on a conventional linac. Methods: Lrad is defined as the least restrictive of the dose difference at each point in the distributions being compared (%D), with dose normalized by the same factor, and the distance to agreement (DTA in millimeters), limited to directions parallel and perpendicular to MLC motion. If %D<%Do, Lrad=%D. Otherwise, if L=%D/DTA>Lo, Lrad=DTA, else Lrad=%D. Lrad fails at any point when Lrad>DTAo or Lrad>%Do. We compared LRAD (Lo=1%/mm, DTAo=2mm, %Do=2%) with Gamma index tool (2%/2mm pass/fail criteria) for IMRT QA with 2D detector arrays. Dose distribution measured for 6 MV and 18 MV x-rays for various field sizes and shapes, including 6 IMRT plans, were compared to measurements made with output, beam flatness, beam symmetry, MLC leaf positions, and detector array translation and rotation adjusted at up to twice published acceptable tolerance. Results: LRAD was more effective than Gamma in detecting a 2% drift in output (dose per monitor unit), 1–2 mm drifts in MLC leaf position for 1–8 leaves in the field, and beam flatness and symmetry drifts that resulted in a 3% change in the off-axis ratio. LRAD and Gamma were equally effective for larger output changes and for detector translations and rotations. For all ∼400 measurements performed, LRAD detected 78% of the error and Gamma detected 52% of the errors. By using a color scale to display dose differences and grey scale for spatial errors, the reason for failure was self evident, whether it be beam or mechanical changes. Conclusion: LRAD proved to be advantageous in its ability to detect and distinguish between realistic changes in beam and mechanical settings in comparison to the Gamma Index.

  19. Is wax equivalent to tissue in electron conformal therapy planning? A Monte Carlo study of material approximation introduced dose difference.

    PubMed

    Zhang, Ray R; Feygelman, Vladimir; Harris, Eleanor R; Rao, Nikhil; Moros, Eduardo G; Zhang, Geoffrey G

    2013-01-07

    With CT-based Monte Carlo (MC) dose calculations, material composition is often assigned based on the standard Hounsfield unit ranges. This is known as the density threshold method. In bolus electron conformal therapy (BolusECT), the bolus material, machineable wax, would be assigned as soft tissue and the electron density is assumed equivalent to soft tissue based on its Hounsfield unit. This study investigates the dose errors introduced by this material assignment. BEAMnrc was used to simulate electron beams from a Trilogy accelerator. SPRRZnrc was used to calculate stopping power ratios (SPR) of tissue to wax, SPR (tissue) (wax), and tissue to water, SPR(tissue) (water), for 6, 9, 12, 15, and 18 MeV electron beams, of which 12 and 15MeV beams are the most commonly used energies in BolusECT. DOSXYZnrc was applied in dose distribution calculations in a tissue phantom with either flat wax slabs of various thicknesses or a wedge-shaped bolus on top. Dose distribution for two clinical cases, a chest wall and a head and neck, were compared with the bolus material treated as wax or tissue. The SPR(tissue) (wax) values for 12 and 15MeV beams are between 0.935 and 0.945, while the SPR(tissue) (water) values are between 0.990 and 0.991. For a 12 MeV beam, the dose in tissue immediately under the bolus is overestimated by 2.5% for a 3 cm bolus thickness if the wax bolus is treated as tissue. For 15 MeV beams, the error is 1.4%. However, in both clinical cases the differences in the PTV DVH is negligible. Due to stopping power differences, dose differences of up to 2.5% are observed in MC simulations if the bolus material is misassigned as tissue in BolusECT dose calculations. However, for boluses thinner than 2 cm that are more likely encountered in practice, the error is within clinical tolerance.

  20. Singular perturbation of absolute stability.

    NASA Technical Reports Server (NTRS)

    Siljak, D. D.

    1972-01-01

    It was previously shown (author, 1969) that the regions of absolute stability in the parameter space can be determined when the parameters appear on the right-hand side of the system equations, i.e., the regular case. Here, the effect on absolute stability of a small parameter attached to higher derivatives in the equations (the singular case) is studied. The Lur'e-Postnikov class of nonlinear systems is considered.

  1. Issues in Absolute Spectral Radiometric Calibration: Intercomparison of Eight Sources

    NASA Technical Reports Server (NTRS)

    Goetz, Alexander F. H.; Kindel, Bruce; Pilewskie, Peter

    1998-01-01

    The application of atmospheric models to AVIRIS and other spectral imaging data to derive surface reflectance requires that the sensor output be calibrated to absolute radiance. Uncertainties in absolute calibration are to be expected, and claims of 92% accuracy have been published. Measurements of accurate surface albedos and cloud absorption to be used in radiative balance calculations depend critically on knowing the absolute spectral-radiometric response of the sensor. The Earth Observing System project is implementing a rigorous program of absolute radiometric calibration for all optical sensors. Since a number of imaging instruments that provide output in terms of absolute radiance are calibrated at different sites, it is important to determine the errors that can be expected among calibration sites. Another question exists about the errors in the absolute knowledge of the exoatmospheric spectral solar irradiance.

  2. Determination of radionuclides and pathways contributing to cumulative dose. Hanford Environmental Dose Reconstruction Project: Dose code recovery activities, Calculation 004

    SciTech Connect

    Napier, B.A.

    1992-12-01

    A series of scoping calculations has been undertaken to evaluate the absolute and relative contributions of different radionuclides and exposure pathways to doses that may have been received by individuals living in the vicinity of the Hanford Site. This scoping calculation (Calculation 004) examined the contributions of numerous radionuclides to cumulative dose via environmental exposures and accumulation in foods. Addressed in this calculation were the contributions to organ and effective dose of infants and adults from (1) air submersion and groundshine external dose, (2) inhalation, (3) ingestion of soil by humans, (4) ingestion of leafy vegetables, (5) ingestion of other vegetables and fruits, (6) ingestion of meat, (7) ingestion of eggs, and (8) ingestion of cows` milk from Feeding Regime 1, as described in calculation 002. This calculation specifically addresses cumulative radiation doses to infants and adults resulting from releases occurring over the period 1945 through 1972.

  3. Application of mesotrione at different doses in an amended soil: Dissipation and effect on the soil microbial biomass and activity.

    PubMed

    Pose-Juan, Eva; Sánchez-Martín, María Jesús; Herrero-Hernández, Eliseo; Rodríguez-Cruz, María Sonia

    2015-12-01

    The aim of this work was to estimate the dissipation of mesotrione applied at three doses (2, 10 and 50 mg kg(-1) dw) in an unamended agricultural soil, and this same soil amended with two organic residues (green compost (C) and sewage sludge (SS)). The effects of herbicide and organic residue on the abundance and activity of soil microbial communities were also assessed by determining soil microbial parameters such as biomass, dehydrogenase activity (DHA), and respiration. Lower dissipation rates were observed for a higher herbicide dose. The highest half-life (DT50) values were observed in the SS-amended soil for the three herbicide doses applied. Biomass values increased in the amended soils compared to the unamended one in all the cases studied, and increased over the incubation period in the SS-amended soil. DHA mean values significantly decreased in the SS-amended soil, and increased in the C-amended soil compared to the unamended ones, under all conditions. At time 0 days, respiration values were significantly higher in SS-amended soils (untreated and treated with mesotrione) than in the unamended and C-amended soils. The effect of mesotrione on soil biomass, DHA and respiration was different depending on incubation time and soil amendment and herbicide dose applied. The results support the need to consider the possible non-target effects of pesticides and organic amendments simultaneously applied on soil microbial communities to prevent negative impacts on soil quality. PMID:26188530

  4. Selenium metabolite levels in human urine after dosing selenium in different chemical forms

    SciTech Connect

    Hasunuma, Ryoichi; Tsuda, Morizo; Ogawa, Tadao; Kawanishi, Yasuhiro

    1993-11-01

    It has been well known that selenium in marine fish such as tuna and swordfish protects the toxicity of methylmercury in vivo. The protective potency might depend on the chemical forms of selenium in the meat of marine fish sebastes and sperm whale. Little has been revealed, however, on the chemical forms of selenium in the meat of these animals or the selenium metabolites in urine, because the amount of the element is very scarce. Urine is the major excretory route for selenium. The chemical forms of urinary selenium may reflect the metabolism of the element. We have developed methodology for analysis of selenium-containing components in human urine. Using this method, we have observed the time courses of excretory levels of urinary selenium components after a single dose of selenium as selenious acid, selenomethionine, trimethylselenonium ion or tuna meat. 14 refs., 6 figs., 1 tab.

  5. Defining Dose across Different Experimental Designs: Fiber Equivalent Diameter and Surface Area

    EPA Science Inventory

    Inhaled fibers (elongated bio-durable particles) of all lengths have been shown to induce pathological responses, but different sizes are respirable in different species. To be able to accurately assess the health effects observed in toxicological or epidemiological studies,...

  6. In vitro gas production of foliage from three browse tree species treated with different dose levels of exogenous fibrolytic enzymes.

    PubMed

    López, D; Vázquez-Armijo, J F; López-Villalobos, N; Lee-Rangel, H A; Salem, A Z M; Borquez-Gastelum, J L; Domínguez-Vara, I A; Rojo-Rubio, R

    2016-10-01

    The aim of this study was to evaluate the effect of different dose levels of exogenous fibrolytic enzymes (EFE) on in vitro ruminal fermentation kinetics and energy utilization of foliages from three browse trees (Pithecellobium dulce, Heliocarpus velutinus and Guazuma ulmifolia). Mixture of EFE product was added to the leaves of the three browse tree species at three dose levels: 0 (control), 3.5 and 7.0 mg/g of DM. Chemical composition of the foliages, including plant secondary metabolites such as total phenolics (TP), saponins (SAP) and aqueous fraction (AF), was determined. In addition, in vitro assaying of ruminal gas production kinetics was determined for the three browse three foliages treated with EFE. P. dulce had the highest crude protein content (p < 0.05), whereas G. ulmifolia had the highest content of neutral detergent fibre and SAP (p < 0.05) and H. velutinus had the lowest content of TP (p < 0.05). The interaction between tree species and dose level of EFE was significant (p < 0.05) for gas production (GP) at 24 h of incubation, parameters b and c of the accumulated GP curve, short-chain fatty acids (SCFA) and metabolizable energy (ME). The lowest (p < 0.01) extent of accumulated GP as well as the b and c values occurred in G. ulmifolia at 0 mg EFE/g DM. P. dulce had the highest (p < 0.05) values for ME and SCFA at the highest dose of EFE. Tree species and dose level had significant (p < 0.05) effects on all parameters describing in vitro ruminal fermentation kinetics and energy utilization. Addition of EFE improved the fermentation kinetics of the browse species considered in this study.

  7. Protection of Eurasian badgers (Meles meles) from tuberculosis after intra-muscular vaccination with different doses of BCG.

    PubMed

    Lesellier, Sandrine; Palmer, Si; Gowtage-Sequiera, Sonya; Ashford, Roland; Dalley, Deanna; Davé, Dipesh; Weyer, Ute; Salguero, F Javier; Nunez, Alejandro; Crawshaw, Timothy; Corner, Leigh A L; Hewinson, R Glyn; Chambers, Mark A

    2011-05-12

    Mycobacterium bovis infection is widespread in Eurasian badger (Meles meles) populations in Great Britain and the Republic of Ireland where they act as a wildlife reservoir of infection for cattle. Removal of infected badgers can significantly reduce the incidence of bovine tuberculosis (TB) in local cattle herds. However, control measures based on culling of native wildlife are contentious and may even be detrimental to disease control. Vaccinating badgers with bacillus Calmette-Guerin (BCG) has been shown to be efficacious against experimentally induced TB of badgers when administered subcutaneously and orally. Vaccination may be an alternative or complementary strategy to other disease control measures. As the subcutaneous route is impractical for vaccinating wild badgers and an oral vaccine bait formulation is currently unavailable, we evaluated the intramuscular (IM) route of BCG administration. It has been demonstrated that the IM route is safe in badgers. IM administration has the practical advantage of being relatively easy to perform on trapped wild badgers without recourse to chemical immobilisation. We report the evaluation of the efficacy of IM administration of BCG Danish strain 1331 at two different doses: the dose prescribed for adult humans (2-8×10(5)colony forming units) and a 10-fold higher dose. Vaccination generated a dose-dependent cell-mediated immune response characterised by the production of interferon-γ (IFNγ) and protection against endobronchial challenge with virulent M. bovis. Protection, expressed in terms of a significant reduction in the severity of disease, the number of tissues containing acid-fast bacilli, and reduced bacterial excretion was statistically significant with the higher dose only.

  8. SU-E-J-11: Measurement of Eye Lens Dose for Varian On-Board Imaging with Different CBCT Acquisition Techniques

    SciTech Connect

    Deshpande, S; Dhote, D; Kumar, R; Thakur, K

    2015-06-15

    Purpose: To measure actual patient eye lens dose for different cone beam computed tomography (CBCT) acquisition protocol of Varian’s On Board Imagining (OBI) system using Optically Stimulated Luminescence (OSL) dosimeter and study the eye lens dose with patient geometry and distance of isocenter to the eye lens Methods: OSL dosimeter was used to measure eye lens dose of patient. OSL dosimeter was placed on patient forehead center during CBCT image acquisition to measure eye lens dose. For three different cone beam acquisition protocol (standard dose head, low dose head and high quality head) of Varian On-Board Imaging, eye lens doses were measured. Measured doses were correlated with patient geometry and distance between isocenter to eye lens. Results: Measured eye lens dose for standard dose head was in the range of 1.8 mGy to 3.2 mGy, for high quality head protocol dose was in range of 4.5mGy to 9.9 mGy whereas for low dose head was in the range of 0.3mGy to 0.7mGy. Dose to eye lens is depends upon position of isocenter. For posterioraly located tumor eye lens dose is less. Conclusion: From measured doses it can be concluded that by proper selection of imagining protocol and frequency of imaging, it is possible to restrict the eye lens dose below the new limit set by ICRP. However, undoubted advantages of imaging system should be counter balanced by careful consideration of imaging protocol especially for very intense imaging sequences for Adoptive Radiotherapy or IMRT.

  9. Comparative evaluation of different doses of intrathecal neostigmine as an adjuvant to bupivacaine for postoperative analgesia

    PubMed Central

    Pandey, Vandana; Mohindra, B. K.; Sodhi, Gurdip Singh

    2016-01-01

    Objective: To study the efficacy and safety of intrathecal neostigmine at dose of 50 μg and 150 μg as an adjuvant to bupivacaine for postoperative analgesia under spinal anesthesia. Materials and Methods: 75 patients of either sex, belonging to American Society of Anesthesiologists (ASA) physical status I and II in the age group of 30-65 years scheduled to undergo lower abdominal and lower limb surgeries were allocated randomly into 3 groups of 25 each. Spinal anesthesia was administered in Group I (control group) with 12.5 mg (2.5 ml) of 0.5% hyperbaric bupivacaine, in Group II (50 μg group) with 12.5 mg (2.5 ml) of 0.5% hyperbaric bupivacaine and 50 μg (0.1 ml) of neostigmine methylsulphate and in Group III (150 μg group) with 12.5 mg (2.5 ml) of 0.5% hyperbaric bupivacaine and 150 μg (0.3 ml) of neostigmine methylsulphate. Hemodynamic parameters, onset and level of sensory block were recorded. Postoperative analgesic assessment was made in terms of total Visual Analogue Scale-Pain (VAS-P) scores in 24 hrs, duration of analgesia (time to requirement of first analgesic) and total number of rescue analgesic (diclofenac sodium 75 mg intramuscularly) consumption in 24 hours. Side effects were recorded. Results: The total VAS-P score in group I was 23.12 ± 3.21, which was higher than the VAS-P score in group II (18.4 ± 2.92) and group III (16.24 ± 1.85). The total duration of analgesia was significantly prolonged in neostigmine groups (224.40 ± 23.28 min in group I, 367.60 ± 42.15 min in group II and 625.60 ± 87.70 min in group III). In group I, the patients required 2.48 ± 0.51 number of analgesics in 24 hours, which was much higher than required in group II (1.92 ± 0.64) and group III (1.32 ± 0.47). The incidence of nausea and vomiting was more with 150 μg neostigmine group compared to 50 μg neostigmine. Conclusions: The administration of intrathecal neostigmine in dose of 50 μg as an adjuvant to bupivacaine produces hemodynamically stable

  10. [Regulation of the neuronal functional state by ultra low doses of different biologically active substances. Nonspecific effect ].

    PubMed

    Terekhova, S F; Grechenko, T N

    2003-01-01

    The role of biologically active substances in ultra-low doses (10(-15)-10(-27) mol/l) is discussed from the different points of view. The most detailed analysis of neurobiological effects produced by these doses can be studied on the preparate of completely isolated molluscan neurones. In this case the possibility arises to control the first modifications of action at the electrophysiological characteristics of neuronal activity. These changes of electrical activity can be regarded as a reaction to biologically active substance. The following characteristics were controlled: the level of membrane resting potential (MP), the electroexcitable membrane and pacemaker mechanism, chemical sensitivity of somatic membrane loci to neurotransmitter acetylcholine (Ach). Several substances were used in these experiments: two kinds of synthetic antioxidant, GABA, ethanol, serotonine, DSIP (delta-sleep inducing peptide), antibiotic ruboxil, nootrop GVS-111. The isolated neurones were placed into the special chamber. All these substances (0.35 ml) were added single dosing into this chamber with living physiological solution in concentration 10(-15)-10(-27) mol/l. The results demonstrated that all substances had initiated the development of prolonged neurophysiological responses. The intensities of neuronal reactions didn't depend in contact period on the concentration and on the type of substance. It is suggested that these data reveal the existence of unknown modes of regulation of neuronal functional states and presence of hidden channel for information transfer and receiving. This different way of regulation is extremely important influence living organisms. PMID:12881986

  11. [High dose medroxyprogesterone acetate in metastatic breast cancer. Comparative clinical, pharmacokinetic and pharmacodynamic data of different forms of administration].

    PubMed

    Blossey, H C; Wander, H E; Nagel, G A; Köbberling, J; Kleeberg, U

    1982-08-01

    In the therapy of metastatic breast cancer MAP was used with different dosages and different forms of administration. Pharmacokinetics and pharmacodynamics were investigated. MAP plasma concentrations are dose dependent with great interindividual variation. The cortisol suppressive effect is dependent on plasma concentrations with only narrow interindividual variability. The oral administration of the crystal suspension is equivalent to the administration of tablets concerning plasma levels und endocrine effects. The therapy schedule for i.m. application used here leads to lower MAP plasma concentrations and correspondingly to a minor endocrine effect than in oral therapy. Tumor effective and cortisol suppressive plasma concentrations seem to have the same level.

  12. Monte Carlo calculations for absolute dosimetry to determine machine outputs for proton therapy fields

    PubMed Central

    Paganetti, Harald

    2008-01-01

    The prescribed dose in radiation therapy has to be converted into machine monitor units for patient treatment. This is done routinely for each spread-out Bragg peak (SOBP) field either by calibration measurements, by using analytical algorithms or by relying on empirical data. At the Northeast Proton Therapy Center, a monitor unit corresponds to a fixed amount of charge collected in a segmented transmission ionization chamber inside the treatment head. The goal of this work was to use a detailed Monte Carlo model of the treatment head to calculate the dose delivered to the patient as a function of ionization chamber reading, i.e. to yield absolute dose in patients in terms of machine monitor units. The results show excellent agreement with measurements. For 50 SOBP fields considered in this study, the mean absolute difference between the experimental and the calculated value is 1.5%, where ~50% of the fields agree within 1%. This is within the uncertainties of the data. The Monte Carlo method has advantages over analytical algorithms because it takes into account scattered and secondary radiation, does not rely on empirical parameters, and provides a tool to study the influence of parts of the treatment head on the ionization chamber reading. Compared to experimental methods the Monte Carlo method has the advantage of being able to verify the dose in the patient geometry. PMID:16723767

  13. Different behavioral effect dose-response profiles in mice exposed to two-carbon chlorinated hydrocarbons: influence of structural and physical properties.

    PubMed

    Umezu, Toyoshi; Shibata, Yasuyuki

    2014-09-01

    The present study aimed to clarify whether dose-response profiles of acute behavioral effects of 1,2-dichloroethane (DCE), 1,1,1-trichloroethane (TCE), trichloroethylene (TRIC), and tetrachloroethylene (PERC) differ. A test battery involving 6 behavioral endpoints was applied to evaluate the effects of DCE, TCE, TRIC, and PERC in male ICR strain mice under the same experimental conditions. The behavioral effect dose-response profiles of these compounds differed. Regression analysis was used to evaluate the relationship between the dose-response profiles and structural and physical properties of the compounds. Dose-response profile differences correlated significantly with differences in specific structural and physical properties. These results suggest that differences in specific structural and physical properties of DCE, TCE, TRIC, and PERC are responsible for differences in behavioral effects that lead to a variety of dose-response profiles.

  14. Absolute flux scale for radioastronomy

    SciTech Connect

    Ivanov, V.P.; Stankevich, K.S.

    1986-07-01

    The authors propose and provide support for a new absolute flux scale for radio astronomy, which is not encumbered with the inadequacies of the previous scales. In constructing it the method of relative spectra was used (a powerful tool for choosing reference spectra). A review is given of previous flux scales. The authors compare the AIS scale with the scale they propose. Both scales are based on absolute measurements by the ''artificial moon'' method, and they are practically coincident in the range from 0.96 to 6 GHz. At frequencies above 6 GHz, 0.96 GHz, the AIS scale is overestimated because of incorrect extrapolation of the spectra of the primary and secondary standards. The major results which have emerged from this review of absolute scales in radio astronomy are summarized.

  15. The absolute spectrophotometric catalog by Anita Cochran

    NASA Astrophysics Data System (ADS)

    Burnashev, V. I.; Burnasheva, B. A.; Ruban, E. V.; Hagen-Torn, E. I.

    2014-06-01

    The absolute spectrophotometric catalog by Anita Cochran is presented in a machine-readable form. The catalog systematizes observations acquired at the McDonald Observatory in 1977-1978. The data are compared with other sources, in particular, the calculated broadband stellar magnitudes are compared with photometric observations by other authors, to show that the observational data given in the catalog are reliable and suitable for a variety of applications. Observations of variable stars of different types make Cochran's catalog especially valuable.

  16. Methods to Analyze Bone Regenerative Response to Different rhBMP-2 Doses in Rabbit Craniofacial Defects

    PubMed Central

    Guda, Teja; Darr, Aniq; Silliman, David T.; Magno, Maria H.R.; Wenke, Joseph C.; Kohn, Joachim

    2014-01-01

    Multiple assessment methods are available to evaluate the performance of engineered scaffolds in accepted bone healing animal models. Evaluation and comparison of these methods can aid in the planning of future animal studies, as well as, inform clinical assessments as the engineered scaffolds translate into clinical studies and applications. To evaluate multiple bone assessment techniques, bone regrowth potential of tyrosine-derived polycarbonate (TyrPC) scaffolds loaded with various dosages of recombinant human bone morphogenetic protein-2 (rhBMP-2) (0, 10, 25, and 50 μg) was assessed after 16 weeks in vivo in a rabbit calvarial model. Traditional X-ray radiography and micro-computed tomography (micro-CT) analyses were used to quantify the volume and density of regenerated bone. Histomorphometric analysis was performed as the traditional gold standard of evaluation. While these techniques are fairly standard in bone tissue engineering, we also investigated 64-slice CT, a tool more commonly used clinically, for comparison and to guide translational efforts. The 64-slice CT scans were carried out at 4 and 16 weeks to monitor temporal bone healing patterns. Study results indicated a clear dose-dependent response of increasing regenerated bone volume with rhBMP-2 loaded on the TyrPC scaffolds after 16 weeks of implantation. Significantly more bone formation was observed at the highest dose of rhBMP-2 (50 μg), which is 25–50% of the previously recommended dose (100–200 μg) for this defect. A significant difference was observed between the lowest and highest doses using radiographs (p<0.001), micro-CT (p=0.002), and CT (p<0.001) and a high correlation was found between techniques (R2 values between 0.446 and 0.911). It was found that the number of animals required per group to detect significant dose effects ranged between 6 and 8 for the imaging methods while histomorphometric analysis would require 25 animals per group to detect similar differences

  17. Pharmacokinetic differences between chlorofluorocarbon and chlorofluorocarbon-free metered dose inhalers of beclomethasone dipropionate in adult asthmatics.

    PubMed

    Harrison, L I; Soria, I; Cline, A C; Ekholm, B P

    1999-11-01

    We have compared the serum pharmacokinetics of the metabolites of beclomethasone dipropionate after inhalation from chlorofluorocarbon (CFC) and hydrofluoroalkane HFA-134a (HFA) formulations in asthmatic patients. Twenty-three patients completed this open-label, randomized, single-dose, three-period crossover study. Each patient received in separate periods 200 microg or 400 microg HFA-beclomethasone dipropionate, or 400 microg CFC-beclomethasone dipropionate. Venous blood samples were collected over 24 h for the determination of beclomethasone esters and beclomethasone in the serum. Significant differences in pharmacokinetics following HFA- and CFC-beclomethasone dipropionate were observed. Following a 400 microg beclomethasone dipropionate dose, the HFA formulation gave mean maximum concentrations (Cmax) and area under the curve (AUC) values of beclomethasone esters of 1153 pg mL(-1) and 4328 pg h mL(-1), respectively, and beclomethasone Cmax and AUC values of 69 pg mL(-1) and 682 pg h mL(-1), respectively. These values were approximately 2-3-fold those seen with the CFC formulation (beclomethasone esters Cmax and AUC of 380 pg mL(-1) and 1764 pg h mL(-1), respectively; beclomethasone Cmax and AUC of 41 pg ml(-1) and 366 pg h mL(-1), respectively). Beclomethasone esters, the major component of beclomethasone dipropionate in the serum, peaked significantly earlier for the HFA formulation (0.8 h) than for the CFC formulation (2 h). Tests for dose proportionality of beclomethasone esters pharmacokinetics following HFA-beclomethasone dipropionate showed that the two hydrofluoroalkane strengths were proportional. The more rapid and greater efficiency of systemic drug delivery of the HFA formulation compared with the CFC formulation can be explained if most of each inhalation from CFC-beclomethasone dipropionate is swallowed and absorbed orally, whereas most of each inhalation from HFA-beclomethasone dipropionate is absorbed through the lungs. There is a need for

  18. Gender Differences in Predictors of Treatment Attrition with High Dose Naltrexone in Cocaine and Alcohol Dependence

    PubMed Central

    Suh, Jesse J.; Pettinati, Helen M.; Kampman, Kyle M.; O’Brien, Charles P.

    2008-01-01

    Recently, we reported that naltrexone at 150mg/day significantly decreased cocaine and alcohol use for men, but not women with co-occurring cocaine and alcohol dependence. The present study is an exploratory investigation of predictors that explain the different gender response to naltrexone, with a particular focus on differential predictors of treatment attrition. No significant predictors were associated with treatment discontinuation in men. Women, however, were more likely to discontinue treatment when reporting severe pre-treatment psychiatric problems, or nausea while in treatment. Further research on the impact of pre-treatment and in-treatment gender differences with naltrexone is warranted. PMID:19034737

  19. Electronic brachytherapy for superficial and nodular basal cell carcinoma: a report of two prospective pilot trials using different doses

    PubMed Central

    Pons-Llanas, Olga; Candela-Juan, Cristian; Celada-Álvarez, Francisco Javier; Barker, Christopher A.; Tormo-Micó, Alejandro; Pérez-Calatayud, Jose; Botella-Estrada, Rafael

    2016-01-01

    Purpose Basal cell carcinoma (BCC) is a very common cancer in the Caucasian population. Treatment aims to eradicate the tumor with the lowest possible functional and aesthetic impact. Electronic brachytherapy (EBT) is a treatment technique currently emerging. This study aims to show the outcomes of two consecutive prospective pilot clinical trials using different radiation doses of EBT with Esteya® EB system for the treatment of superficial and nodular basal cell carcinoma. Material and methods Two prospective, single-center, non-randomized, pilot studies were conducted. Twenty patients were treated in each study with different doses. The first group (1) was treated with 36.6 Gy in 6 fractions of 6.1 Gy, and the second group (2) with 42 Gy in 6 fractions of 7 Gy. Cure rate, acute toxicity, and late toxicity related to cosmesis were analyzed in the two treatment groups. Results In group 1, a complete response in 90% of cases was observed at the first year of follow-up, whereas in group 2, the complete response was 95%. The differences with reference to acute toxicity and the cosmetic results between the two treatment groups were not statistically significant. Conclusions Our initial experience with Esteya® EB system to treat superficial and nodular BCC shows that a dose of 36.6 Gy and 42 Gy delivered in 6 fraction of 7 Gy achieves a 90% and 95% clinical cure rate at 1 year, respectively. Both groups had a tolerable toxicity and a very good cosmesis. The role of EBT in the treatment of BCC is still to be defined. It will probably become an established option for selected patients in the near future. PMID:26985197

  20. Different doses of prophylactic platelet transfusion for preventing bleeding in people with haematological disorders after myelosuppressive chemotherapy or stem cell transplantation

    PubMed Central

    Estcourt, Lise J; Stanworth, Simon; Doree, Carolyn; Trivella, Marialena; Hopewell, Sally; Blanco, Patricia; Murphy, Michael F

    2015-01-01

    Background Platelet transfusions are used in modern clinical practice to prevent and treat bleeding in people who are thrombocytopenic due to bone marrow failure. Although considerable advances have been made in platelet transfusion therapy in the last 40 years, some areas continue to provoke debate, especially concerning the use of prophylactic platelet transfusions for the prevention of thrombocytopenic bleeding. This is an update of a Cochrane review first published in 2004, and updated in 2012 that addressed four separate questions: prophylactic versus therapeutic-only platelet transfusion policy; prophylactic platelet transfusion threshold; prophylactic platelet transfusion dose; and platelet transfusions compared to alternative treatments. This review has now been split into four smaller reviews; this review compares different platelet transfusion doses. Objectives To determine whether different doses of prophylactic platelet transfusions (platelet transfusions given to prevent bleeding) affect their efficacy and safety in preventing bleeding in people with haematological disorders undergoing myelosuppressive chemotherapy with or without haematopoietic stem cell transplantation (HSCT). Search methods We searched for randomised controlled trials in the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library 2015, Issue 6), MEDLINE (from 1946), Embase (from 1974), CINAHL (from 1937), the Transfusion Evidence Library (from 1950), and ongoing trial databases to 23 July 2015. Selection criteria Randomised controlled trials involving transfusions of platelet concentrates, prepared either from individual units of whole blood or by apheresis, and given to prevent bleeding in people with malignant haematological disorders or undergoing HSCT that compared different platelet component doses (low dose 1.1 × 1011/m2 ± 25%, standard dose 2.2 × 1011/m2 ± 25%, high dose 4.4 × 1011/m2 ± 25%). Data collection and analysis We used the standard

  1. Relativistic Absolutism in Moral Education.

    ERIC Educational Resources Information Center

    Vogt, W. Paul

    1982-01-01

    Discusses Emile Durkheim's "Moral Education: A Study in the Theory and Application of the Sociology of Education," which holds that morally healthy societies may vary in culture and organization but must possess absolute rules of moral behavior. Compares this moral theory with current theory and practice of American educators. (MJL)

  2. Absolute transition probabilities of phosphorus.

    NASA Technical Reports Server (NTRS)

    Miller, M. H.; Roig, R. A.; Bengtson, R. D.

    1971-01-01

    Use of a gas-driven shock tube to measure the absolute strengths of 21 P I lines and 126 P II lines (from 3300 to 6900 A). Accuracy for prominent, isolated neutral and ionic lines is estimated to be 28 to 40% and 18 to 30%, respectively. The data and the corresponding theoretical predictions are examined for conformity with the sum rules.-

  3. Probing absolute spin polarization at the nanoscale.

    PubMed

    Eltschka, Matthias; Jäck, Berthold; Assig, Maximilian; Kondrashov, Oleg V; Skvortsov, Mikhail A; Etzkorn, Markus; Ast, Christian R; Kern, Klaus

    2014-12-10

    Probing absolute values of spin polarization at the nanoscale offers insight into the fundamental mechanisms of spin-dependent transport. Employing the Zeeman splitting in superconducting tips (Meservey-Tedrow-Fulde effect), we introduce a novel spin-polarized scanning tunneling microscopy that combines the probing capability of the absolute values of spin polarization with precise control at the atomic scale. We utilize our novel approach to measure the locally resolved spin polarization of magnetic Co nanoislands on Cu(111). We find that the spin polarization is enhanced by 65% when increasing the width of the tunnel barrier by only 2.3 Å due to the different decay of the electron orbitals into vacuum. PMID:25423049

  4. A Methodology for Absolute Isotope Composition Measurement

    NASA Astrophysics Data System (ADS)

    Shen, J. J.; Lee, D.; Liang, W.

    2007-12-01

    Double spike technique was a well defined method for isotope composition measurement by TIMS of samples which have natural mass fractionation effect, but it is still a problem to define the isotope composition for double spike itself. In this study, we modified the old double spike technique and found that we could use the modified technique to solve the ¡§true¡¨ isotope composition of double spike itself. According the true isotope composition of double spike, we can measure the absolute isotope composition if the sample has natural fractionation effect. A new vector analytical method has been developed in order to obtain the true isotopic composition of a 42Ca-48Ca double spike, and this is achieved by using two different sample-spike mixtures combined with the double spike and the natural Ca data. Because the natural sample, the two mixtures, and the spike should all lie on a single mixing line, we are able to constrain the true isotopic composition of our double spike using this new approach. This method not only can be used in Ca system but also in Ti, Cr, Fe, Ni, Zn, Mo, Ba and Pb systems. The absolute double spike isotopic ratio is important, which can save a lot of time to check different reference standards. Especially for Pb, radiogenic isotope system, the decay systems embodied in three of four naturally occurring isotopes induce difficult to obtain true isotopic ratios for absolute dating.

  5. Effect of the normalized prescription isodose line on the magnitude of Monte Carlo vs. pencil beam target dose differences for lung stereotactic body radiotherapy.

    PubMed

    Zheng, Dandan; Zhang, Qinghui; Liang, Xiaoying; Zhu, Xiaofeng; Verma, Vivek; Wang, Shuo; Zhou, Sumin

    2016-07-08

    In lung stereotactic body radiotherapy (SBRT) cases, the pencil beam (PB) dose calculation algorithm is known to overestimate target dose as compared to the more accurate Monte Carlo (MC) algorithm. We investigated whether changing the normalized prescription isodose line affected the magnitude of MC vs. PB target dose differences. Forty-eight patient plans and twenty virtual-tumor phantom plans were studied. For patient plans, four alternative plans prescribed to 60%, 70%, 80%, and 90% isodose lines were each created for 12 patients who previously received lung SBRT treatments. Using 6 MV dynamic conformal arcs, the plans were individually optimized to achieve similar dose coverage and conformity for all plans of the same patient, albeit at the different prescription levels. These plans, having used a PB algorithm, were all recalculated with MC to compare the target dose differences. The relative MC vs. PB target dose variations were investigated by comparing PTV D95, Dmean, and D5 loss at the four prescription levels. The MC-to-PB ratio of the plan heterogeneity index (HI) was also evaluated and compared among different isodose levels. To definitively demonstrate the cause of the isodose line dependence, a simulated phantom study was conducted using simple, spherical virtual tumors planned with uniform block margins. The tumor size and beam energy were also altered in the phantom study to investigate the interplay between these confounding factors and the isodose line effect. The magnitude of the target dose overestimation by PB was greater for higher prescription isodose levels. The MC vs. PB reduction in the target dose coverage indices, D95 and V100 of PTV, were found to monotonically increase with increasing isodose lines from 60% to 90%, resulting in more pronounced target dose coverage deficiency at higher isodose prescription levels. No isodose level-dependent trend was observed for the dose errors in the target mean or high dose indices, Dmean or D5. The

  6. In vitro gas production of foliage from three browse tree species treated with different dose levels of exogenous fibrolytic enzymes.

    PubMed

    López, D; Vázquez-Armijo, J F; López-Villalobos, N; Lee-Rangel, H A; Salem, A Z M; Borquez-Gastelum, J L; Domínguez-Vara, I A; Rojo-Rubio, R

    2016-10-01

    The aim of this study was to evaluate the effect of different dose levels of exogenous fibrolytic enzymes (EFE) on in vitro ruminal fermentation kinetics and energy utilization of foliages from three browse trees (Pithecellobium dulce, Heliocarpus velutinus and Guazuma ulmifolia). Mixture of EFE product was added to the leaves of the three browse tree species at three dose levels: 0 (control), 3.5 and 7.0 mg/g of DM. Chemical composition of the foliages, including plant secondary metabolites such as total phenolics (TP), saponins (SAP) and aqueous fraction (AF), was determined. In addition, in vitro assaying of ruminal gas production kinetics was determined for the three browse three foliages treated with EFE. P. dulce had the highest crude protein content (p < 0.05), whereas G. ulmifolia had the highest content of neutral detergent fibre and SAP (p < 0.05) and H. velutinus had the lowest content of TP (p < 0.05). The interaction between tree species and dose level of EFE was significant (p < 0.05) for gas production (GP) at 24 h of incubation, parameters b and c of the accumulated GP curve, short-chain fatty acids (SCFA) and metabolizable energy (ME). The lowest (p < 0.01) extent of accumulated GP as well as the b and c values occurred in G. ulmifolia at 0 mg EFE/g DM. P. dulce had the highest (p < 0.05) values for ME and SCFA at the highest dose of EFE. Tree species and dose level had significant (p < 0.05) effects on all parameters describing in vitro ruminal fermentation kinetics and energy utilization. Addition of EFE improved the fermentation kinetics of the browse species considered in this study. PMID:27080456

  7. Determination of dose distributions and parameter sensitivity. Hanford Environmental Dose Reconstruction Project; dose code recovery activities; Calculation 005

    SciTech Connect

    Napier, B.A.; Farris, W.T.; Simpson, J.C.

    1992-12-01

    A series of scoping calculations has been undertaken to evaluate the absolute and relative contribution of different radionuclides and exposure pathways to doses that may have been received by individuals living in the vicinity of the Hanford site. This scoping calculation (Calculation 005) examined the contributions of numerous parameters to the uncertainty distribution of doses calculated for environmental exposures and accumulation in foods. This study builds on the work initiated in the first scoping study of iodine in cow`s milk and the third scoping study, which added additional pathways. Addressed in this calculation were the contributions to thyroid dose of infants from (1) air submersion and groundshine external dose, (2) inhalation, (3) ingestion of soil by humans, (4) ingestion of leafy vegetables, (5) ingestion of other vegetables and fruits, (6) ingestion of meat, (7) ingestion of eggs, and (8) ingestion of cows` milk from Feeding Regime 1 as described in Calculation 001.

  8. Mercury demethylation in waterbird livers: Dose-response thresholds and differences among species

    USGS Publications Warehouse

    Eagles-Smith, C. A.; Ackerman, J.T.; Julie, Y.E.E.; Adelsbach, T.L.

    2009-01-01

    We assessed methylmercury (MeHg) demethylation in the livers of adults and chicks of four waterbird species that commonly breed in San Francisco Bay: American avocets, black-necked stilts, Caspian terns, and Forster's terns. In adults (all species combined), we found strong evidence for a threshold, model where MeHg demethylation occurred above a hepatic total mercury concentration threshold of 8.51 ?? 0.93 ??g/g dry weight, and there was a strong decline in %MeHg values as total mercury (THg) concentrations increased above 8.51 ??g/g dry weight. Conversely, there was no evidence for a demethylation threshold in chicks, and we found that %MeHg values declined linearly with increasing THg concentrations. For adults, we also found taxonomie differences in the demethylation responses, with avocets and stilts showing a higher demethylation rate than that of terns when concentrations exceeded the threshold, whereas terns had a lower demethylation threshold (7.48 ?? 1.48 ??g/g dry wt) than that of avocets and stilts (9.91 ?? 1.29 ??g/g dry wt). Finally, we assessed the role of selenium (Se) in the demethylation process. Selenium concentrations were positively correlated with inorganic Hg in livers of birds above the demethylation threshold but not below. This suggests that Se may act as a binding site for demethylated Hg and may reduce the potential for secondary toxicity. Our findings indicate that waterbirds demethylate mercury in their livers if exposure exceeds a threshold value and suggest that taxonomie differences in demethylation ability may be an important factor in evaluating species-specific risk to MeHg exposure. Further, we provide strong evidence for a threshold of approximately 8.5 ??g/g dry weight of THg in the liver where demethylation is initiated. ?? 2009 SETAC.

  9. Determination of dose distributions and parameter sensitivity

    SciTech Connect

    Napier, B.A.; Farris, W.T.; Simpson, J.C.

    1992-12-01

    A series of scoping calculations has been undertaken to evaluate the absolute and relative contribution of different radionuclides and exposure pathways to doses that may have been received by individuals living in the vicinity of the Hanford site. This scoping calculation (Calculation 005) examined the contributions of numerous parameters to the uncertainty distribution of doses calculated for environmental exposures and accumulation in foods. This study builds on the work initiated in the first scoping study of iodine in cow's milk and the third scoping study, which added additional pathways. Addressed in this calculation were the contributions to thyroid dose of infants from (1) air submersion and groundshine external dose, (2) inhalation, (3) ingestion of soil by humans, (4) ingestion of leafy vegetables, (5) ingestion of other vegetables and fruits, (6) ingestion of meat, (7) ingestion of eggs, and (8) ingestion of cows' milk from Feeding Regime 1 as described in Calculation 001.

  10. Effects of Dietary Different Doses of Copper and High Fructose Feeding on Rat Fecal Metabolome.

    PubMed

    Wei, Xiaoli; Song, Ming; Yin, Xinmin; Schuschke, Dale A; Koo, Imhoi; McClain, Craig J; Zhang, Xiang

    2015-09-01

    The gut microbiota plays a critical role in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). Increased fructose consumption and inadequate copper intake are two critical risk factors in the development of NAFLD. To gain insight into the role of gut microbiota, fecal metabolites, obtained from rats exposed to different dietary levels of copper with and without high fructose intake for 4 weeks, were analyzed by comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOF MS). In parallel, liver tissues were assessed by histology and triglyceride assay. Our data showed that high fructose feeding led to obvious hepatic steatosis in both marginal copper deficient rats and copper supplementation rats. Among the 38 metabolites detected with significant abundance alteration between groups, short chain fatty acids were markedly decreased with excessive fructose intake irrespective of copper levels. C15:0 and C17:0 long chain fatty acids, produced only by bacteria, were increased by either high copper level or high fructose intake. In addition, increased fecal urea and malic acid paralleled the increased hepatic fat accumulation. Collectively, GC × GC-TOF MS analysis of rat fecal samples revealed distinct fecal metabolome profiles associated with the dietary high fructose and copper level, with some metabolites possibly serving as potential noninvasive biomarkers of fructose induced-NAFLD.

  11. Factors affecting stomatal uptake of ozone by different canopies and a comparison between dose and exposure.

    PubMed

    Zhang, Leiming; Vet, Robert; Brook, Jeffrey R; Legge, Allan H

    2006-10-15

    Measured ozone (O(3)) and carbon dioxide (CO(2)) concentrations and fluxes over five different canopies (mixed coniferous-deciduous forest, deciduous forest, corn, soybean and pasture) in the eastern USA were analyzed to investigate the stomatal uptake of O(3). It was found that the ambient O(3) concentration levels had little effect on stomatal conductance. However, the accumulated stomatal uptake of O(3), upon reaching a threshold value on any given day, appears to reduce the rate of further O(3) uptake substantially. This may explain why the maximum O(3) deposition velocity often appeared in the early morning hours over some forest canopies. Substantially reduced CO(2) fluxes over wet canopies compared to dry canopies suggest that stomata were likely partially or totally blocked by water droplets or films when canopies were wet. By using a big-leaf dry deposition model, measured O(3) fluxes were separated into stomatal and non-stomatal portions. It was estimated that stomatal uptake contributed 55-75% of the total daytime O(3) fluxes and 40-60% of the total daytime plus nighttime fluxes, depending on canopy type. This suggests that about half of the total O(3) flux occurred through the non-stomatal pathway. At three locations (deciduous forest, corn and soybean sites), O(3) concentrations of 30-60 ppb and of 60-85 ppb contributed equally to the accumulated stomatal fluxes, while at the other two locations (mixed coniferous-deciduous forest and pasture sites), concentrations of 30-60 ppb contributed twice as much as those from 60 to 85 ppb.

  12. Curtailing patient-specific IMRT QA procedures from 2D dose error distribution

    PubMed Central

    Kurosu, Keita; Sumida, Iori; Mizuno, Hirokazu; Otani, Yuki; Oda, Michio; Isohashi, Fumiaki; Seo, Yuji; Suzuki, Osamu; Ogawa, Kazuhiko

    2016-01-01

    A patient-specific quality assurance (QA) test is conducted to verify the accuracy of dose delivery. It generally consists of three verification processes: the absolute point dose difference, the planar dose differences at each gantry angle, and the planar dose differences by 3D composite irradiation. However, this imposes a substantial workload on medical physicists. The objective of this study was to determine whether our novel method that predicts the 3D delivered dose allows certain patient-specific IMRT QAs to be curtailed. The object was IMRT QA for the pelvic region with regard to point dose and composite planar dose differences. We compared measured doses, doses calculated in the treatment planning system, and doses predicted by in-house software. The 3D predicted dose was reconstructed from the per-field measurement by incorporating the relative dose error distribution into the original dose grid of each beam. All point dose differences between the measured and the calculated dose were within ±3%, whereas 93.3% of them between the predicted and the calculated dose were within ±3%. As for planar dose differences, the gamma passing rates between the calculated and the predicted dose were higher than those between the calculated and the measured dose. Comparison and statistical analysis revealed a correlation between the predicted and the measured dose with regard to both point dose and planar dose differences. We concluded that the prediction-based approach is an accurate substitute for the conventional measurement-based approach in IMRT QA for the pelvic region. Our novel approach will help medical physicists save time on IMRT QA. PMID:26661854

  13. Evaluation of the Effect of Two Different Systemic Doses of Viola Odorata on Prevention of Induced Tongue Dysplasia in Rats

    PubMed Central

    Helli, Sanaz; Damghani, Hossein; Mohajeri, Daryoush; Mesgari Abbasi, Mehran; Attaran, Rana; Zahed, Maryam

    2016-01-01

    Statement of the Problem Oral cancer is among the ten most common cancers worldwide. It affects the life quality of patients in many ways. Purpose The aim of this study was to compare the effects of two different systemic doses of Viola Odorata syrup on the prevention of 4-Nitroquinoline-1-oxide (4-NQO) induced tongue dysplasia in rats. Materials and Method Forty-eight male Wistar rats were divided into four groups of A, B, C and D. Group A served as the control group. The rats in groups B to D received 30 ppm of 4-NQO in drinking water for 12 weeks. Additionally, the rats in groups B and C received Viola Odorata syrup at doses of 15 and 5 ml/kg, respectively, 3 times a week. Body weights were measured three times a week. At the end, the rats were euthanized and the tongue was removed. Histological evaluations for carcinogenesis were carried out under a light microscope. Results The mean body weight of the rats in groups B, C, and D were lower than that in group A (p< 0.01). After 12 weeks of treatment, microscopically no histological changes of the tongue base epithelia were observed in the control group. The rats in group B did not show severe dysplastic changes; only mild to moderate histological changes including hyperplasia and hyperkeratosis were evident. These incidences were significantly more apparent in groups C with moderate to severe changes (p< 0.05) and group D with severe dysplastic changes (p< 0.01). Almost all rats in group D had hyperplasia and manifested all of the stages of dysplasia. Conclusion Viola Odorata extract has dose-dependent inhibitory effects on the development of tongue induced dysplasia. PMID:27602393

  14. Evaluation of the Effect of Two Different Systemic Doses of Viola Odorata on Prevention of Induced Tongue Dysplasia in Rats

    PubMed Central

    Helli, Sanaz; Damghani, Hossein; Mohajeri, Daryoush; Mesgari Abbasi, Mehran; Attaran, Rana; Zahed, Maryam

    2016-01-01

    Statement of the Problem Oral cancer is among the ten most common cancers worldwide. It affects the life quality of patients in many ways. Purpose The aim of this study was to compare the effects of two different systemic doses of Viola Odorata syrup on the prevention of 4-Nitroquinoline-1-oxide (4-NQO) induced tongue dysplasia in rats. Materials and Method Forty-eight male Wistar rats were divided into four groups of A, B, C and D. Group A served as the control group. The rats in groups B to D received 30 ppm of 4-NQO in drinking water for 12 weeks. Additionally, the rats in groups B and C received Viola Odorata syrup at doses of 15 and 5 ml/kg, respectively, 3 times a week. Body weights were measured three times a week. At the end, the rats were euthanized and the tongue was removed. Histological evaluations for carcinogenesis were carried out under a light microscope. Results The mean body weight of the rats in groups B, C, and D were lower than that in group A (p< 0.01). After 12 weeks of treatment, microscopically no histological changes of the tongue base epithelia were observed in the control group. The rats in group B did not show severe dysplastic changes; only mild to moderate histological changes including hyperplasia and hyperkeratosis were evident. These incidences were significantly more apparent in groups C with moderate to severe changes (p< 0.05) and group D with severe dysplastic changes (p< 0.01). Almost all rats in group D had hyperplasia and manifested all of the stages of dysplasia. Conclusion Viola Odorata extract has dose-dependent inhibitory effects on the development of tongue induced dysplasia.

  15. Chemical composition of French mimosa absolute oil.

    PubMed

    Perriot, Rodolphe; Breme, Katharina; Meierhenrich, Uwe J; Carenini, Elise; Ferrando, Georges; Baldovini, Nicolas

    2010-02-10

    Since decades mimosa (Acacia dealbata) absolute oil has been used in the flavor and perfume industry. Today, it finds an application in over 80 perfumes, and its worldwide industrial production is estimated five tons per year. Here we report on the chemical composition of French mimosa absolute oil. Straight-chain analogues from C6 to C26 with different functional groups (hydrocarbons, esters, aldehydes, diethyl acetals, alcohols, and ketones) were identified in the volatile fraction. Most of them are long-chain molecules: (Z)-heptadec-8-ene, heptadecane, nonadecane, and palmitic acid are the most abundant, and constituents such as 2-phenethyl alcohol, methyl anisate, and ethyl palmitate are present in smaller amounts. The heavier constituents were mainly triterpenoids such as lupenone and lupeol, which were identified as two of the main components. (Z)-Heptadec-8-ene, lupenone, and lupeol were quantified by GC-MS in SIM mode using external standards and represents 6%, 20%, and 7.8% (w/w) of the absolute oil. Moreover, odorant compounds were extracted by SPME and analyzed by GC-sniffing leading to the perception of 57 odorant zones, of which 37 compounds were identified by their odorant description, mass spectrum, retention index, and injection of the reference compound. PMID:20070087

  16. Chemical composition of French mimosa absolute oil.

    PubMed

    Perriot, Rodolphe; Breme, Katharina; Meierhenrich, Uwe J; Carenini, Elise; Ferrando, Georges; Baldovini, Nicolas

    2010-02-10

    Since decades mimosa (Acacia dealbata) absolute oil has been used in the flavor and perfume industry. Today, it finds an application in over 80 perfumes, and its worldwide industrial production is estimated five tons per year. Here we report on the chemical composition of French mimosa absolute oil. Straight-chain analogues from C6 to C26 with different functional groups (hydrocarbons, esters, aldehydes, diethyl acetals, alcohols, and ketones) were identified in the volatile fraction. Most of them are long-chain molecules: (Z)-heptadec-8-ene, heptadecane, nonadecane, and palmitic acid are the most abundant, and constituents such as 2-phenethyl alcohol, methyl anisate, and ethyl palmitate are present in smaller amounts. The heavier constituents were mainly triterpenoids such as lupenone and lupeol, which were identified as two of the main components. (Z)-Heptadec-8-ene, lupenone, and lupeol were quantified by GC-MS in SIM mode using external standards and represents 6%, 20%, and 7.8% (w/w) of the absolute oil. Moreover, odorant compounds were extracted by SPME and analyzed by GC-sniffing leading to the perception of 57 odorant zones, of which 37 compounds were identified by their odorant description, mass spectrum, retention index, and injection of the reference compound.

  17. Optomechanics for absolute rotation detection

    NASA Astrophysics Data System (ADS)

    Davuluri, Sankar

    2016-07-01

    In this article, we present an application of optomechanical cavity for the absolute rotation detection. The optomechanical cavity is arranged in a Michelson interferometer in such a way that the classical centrifugal force due to rotation changes the length of the optomechanical cavity. The change in the cavity length induces a shift in the frequency of the cavity mode. The phase shift corresponding to the frequency shift in the cavity mode is measured at the interferometer output to estimate the angular velocity of absolute rotation. We derived an analytic expression to estimate the minimum detectable rotation rate in our scheme for a given optomechanical cavity. Temperature dependence of the rotation detection sensitivity is studied.

  18. Moral absolutism and ectopic pregnancy.

    PubMed

    Kaczor, C

    2001-02-01

    If one accepts a version of absolutism that excludes the intentional killing of any innocent human person from conception to natural death, ectopic pregnancy poses vexing difficulties. Given that the embryonic life almost certainly will die anyway, how can one retain one's moral principle and yet adequately respond to a situation that gravely threatens the life of the mother and her future fertility? The four options of treatment most often discussed in the literature are non-intervention, salpingectomy (removal of tube with embryo), salpingostomy (removal of embryo alone), and use of methotrexate (MXT). In this essay, I review these four options and introduce a fifth (the milking technique). In order to assess these options in terms of the absolutism mentioned, it will also be necessary to discuss various accounts of the intention/foresight distinction. I conclude that salpingectomy, salpingostomy, and the milking technique are compatible with absolutist presuppositions, but not the use of methotrexate.

  19. Moral absolutism and ectopic pregnancy.

    PubMed

    Kaczor, C

    2001-02-01

    If one accepts a version of absolutism that excludes the intentional killing of any innocent human person from conception to natural death, ectopic pregnancy poses vexing difficulties. Given that the embryonic life almost certainly will die anyway, how can one retain one's moral principle and yet adequately respond to a situation that gravely threatens the life of the mother and her future fertility? The four options of treatment most often discussed in the literature are non-intervention, salpingectomy (removal of tube with embryo), salpingostomy (removal of embryo alone), and use of methotrexate (MXT). In this essay, I review these four options and introduce a fifth (the milking technique). In order to assess these options in terms of the absolutism mentioned, it will also be necessary to discuss various accounts of the intention/foresight distinction. I conclude that salpingectomy, salpingostomy, and the milking technique are compatible with absolutist presuppositions, but not the use of methotrexate. PMID:11262641

  20. The Absolute Spectrum Polarimeter (ASP)

    NASA Technical Reports Server (NTRS)

    Kogut, A. J.

    2010-01-01

    The Absolute Spectrum Polarimeter (ASP) is an Explorer-class mission to map the absolute intensity and linear polarization of the cosmic microwave background and diffuse astrophysical foregrounds over the full sky from 30 GHz to 5 THz. The principal science goal is the detection and characterization of linear polarization from an inflationary epoch in the early universe, with tensor-to-scalar ratio r much greater than 1O(raised to the power of { -3}) and Compton distortion y < 10 (raised to the power of{-6}). We describe the ASP instrument and mission architecture needed to detect the signature of an inflationary epoch in the early universe using only 4 semiconductor bolometers.

  1. Classification images predict absolute efficiency.

    PubMed

    Murray, Richard F; Bennett, Patrick J; Sekuler, Allison B

    2005-02-24

    How well do classification images characterize human observers' strategies in perceptual tasks? We show mathematically that from the classification image of a noisy linear observer, it is possible to recover the observer's absolute efficiency. If we could similarly predict human observers' performance from their classification images, this would suggest that the linear model that underlies use of the classification image method is adequate over the small range of stimuli typically encountered in a classification image experiment, and that a classification image captures most important aspects of human observers' performance over this range. In a contrast discrimination task and in a shape discrimination task, we found that observers' absolute efficiencies were generally well predicted by their classification images, although consistently slightly (approximately 13%) higher than predicted. We consider whether a number of plausible nonlinearities can account for the slight under prediction, and of these we find that only a form of phase uncertainty can account for the discrepancy.

  2. Absolute calibration of optical flats

    DOEpatents

    Sommargren, Gary E.

    2005-04-05

    The invention uses the phase shifting diffraction interferometer (PSDI) to provide a true point-by-point measurement of absolute flatness over the surface of optical flats. Beams exiting the fiber optics in a PSDI have perfect spherical wavefronts. The measurement beam is reflected from the optical flat and passed through an auxiliary optic to then be combined with the reference beam on a CCD. The combined beams include phase errors due to both the optic under test and the auxiliary optic. Standard phase extraction algorithms are used to calculate this combined phase error. The optical flat is then removed from the system and the measurement fiber is moved to recombine the two beams. The newly combined beams include only the phase errors due to the auxiliary optic. When the second phase measurement is subtracted from the first phase measurement, the absolute phase error of the optical flat is obtained.

  3. Relative errors can cue absolute visuomotor mappings.

    PubMed

    van Dam, Loes C J; Ernst, Marc O

    2015-12-01

    When repeatedly switching between two visuomotor mappings, e.g. in a reaching or pointing task, adaptation tends to speed up over time. That is, when the error in the feedback corresponds to a mapping switch, fast adaptation occurs. Yet, what is learned, the relative error or the absolute mappings? When switching between mappings, errors with a size corresponding to the relative difference between the mappings will occur more often than other large errors. Thus, we could learn to correct more for errors with this familiar size (Error Learning). On the other hand, it has been shown that the human visuomotor system can store several absolute visuomotor mappings (Mapping Learning) and can use associated contextual cues to retrieve them. Thus, when contextual information is present, no error feedback is needed to switch between mappings. Using a rapid pointing task, we investigated how these two types of learning may each contribute when repeatedly switching between mappings in the absence of task-irrelevant contextual cues. After training, we examined how participants changed their behaviour when a single error probe indicated either the often-experienced error (Error Learning) or one of the previously experienced absolute mappings (Mapping Learning). Results were consistent with Mapping Learning despite the relative nature of the error information in the feedback. This shows that errors in the feedback can have a double role in visuomotor behaviour: they drive the general adaptation process by making corrections possible on subsequent movements, as well as serve as contextual cues that can signal a learned absolute mapping. PMID:26280315

  4. Absolute magnitudes and kinematics of barium stars.

    NASA Astrophysics Data System (ADS)

    Gomez, A. E.; Luri, X.; Grenier, S.; Prevot, L.; Mennessier, M. O.; Figueras, F.; Torra, J.

    1997-03-01

    The absolute magnitude of barium stars has been obtained from kinematical data using a new algorithm based on the maximum-likelihood principle. The method allows to separate a sample into groups characterized by different mean absolute magnitudes, kinematics and z-scale heights. It also takes into account, simultaneously, the censorship in the sample and the errors on the observables. The method has been applied to a sample of 318 barium stars. Four groups have been detected. Three of them show a kinematical behaviour corresponding to disk population stars. The fourth group contains stars with halo kinematics. The luminosities of the disk population groups spread a large range. The intrinsically brightest one (M_v_=-1.5mag, σ_M_=0.5mag) seems to be an inhomogeneous group containing barium binaries as well as AGB single stars. The most numerous group (about 150 stars) has a mean absolute magnitude corresponding to stars in the red giant branch (M_v_=0.9mag, σ_M_=0.8mag). The third group contains barium dwarfs, the obtained mean absolute magnitude is characteristic of stars on the main sequence or on the subgiant branch (M_v_=3.3mag, σ_M_=0.5mag). The obtained mean luminosities as well as the kinematical results are compatible with an evolutionary link between barium dwarfs and classical barium giants. The highly luminous group is not linked with these last two groups. More high-resolution spectroscopic data will be necessary in order to better discriminate between barium and non-barium stars.

  5. Differences in dose-volumetric data between the analytical anisotropic algorithm and the x-ray voxel Monte Carlo algorithm in stereotactic body radiation therapy for lung cancer

    SciTech Connect

    Mampuya, Wambaka Ange; Matsuo, Yukinori; Nakamura, Akira; Nakamura, Mitsuhiro; Mukumoto, Nobutaka; Miyabe, Yuki; Narabayashi, Masaru; Sakanaka, Katsuyuki; Mizowaki, Takashi; Hiraoka, Masahiro

    2013-04-01

    The objective of this study was to evaluate the differences in dose-volumetric data obtained using the analytical anisotropic algorithm (AAA) vs the x-ray voxel Monte Carlo (XVMC) algorithm for stereotactic body radiation therapy (SBRT) for lung cancer. Dose-volumetric data from 20 patients treated with SBRT for solitary lung cancer generated using the iPlan XVMC for the Novalis system consisting of a 6-MV linear accelerator and micro-multileaf collimators were recalculated with the AAA in Eclipse using the same monitor units and identical beam setup. The mean isocenter dose was 100.2% and 98.7% of the prescribed dose according to XVMC and AAA, respectively. Mean values of the maximal dose (D{sub max}), the minimal dose (D{sub min}), and dose received by 95% volume (D{sub 95}) for the planning target volume (PTV) with XVMC were 104.3%, 75.1%, and 86.2%, respectively. When recalculated with the AAA, those values were 100.8%, 77.1%, and 85.4%, respectively. Mean dose parameter values considered for the normal lung, namely the mean lung dose, V{sub 5}, and V{sub 20}, were 3.7 Gy, 19.4%, and 5.0% for XVMC and 3.6 Gy, 18.3%, and 4.7% for the AAA, respectively. All of these dose-volumetric differences between the 2 algorithms were within 5% of the prescribed dose. The effect of PTV size and tumor location, respectively, on the differences in dose parameters for the PTV between the AAA and XVMC was evaluated. A significant effect of the PTV on the difference in D{sub 95} between the AAA and XVMC was observed (p = 0.03). Differences in the marginal doses, namely D{sub min} and D{sub 95}, were statistically significant between peripherally and centrally located tumors (p = 0.04 and p = 0.02, respectively). Tumor location and volume might have an effect on the differences in dose-volumetric parameters. The differences between AAA and XVMC were considered to be within an acceptable range (<5 percentage points)

  6. Angular dependence of dose sensitivity of nanoDot optically stimulated luminescent dosimeters in different radiation geometries

    SciTech Connect

    Jursinic, Paul A.

    2015-10-15

    Purpose: A type of in vivo dosimeter, an optically stimulated luminescent dosimeter, OSLD, may have dose sensitivity that depends on the angle of incidence of radiation. This work measures how angular dependence of a nanoDot changes with the geometry of the phantom in which irradiation occurs and with the intrinsic structure of the nanoDot. Methods: The OSLDs used in this work were nanoDot dosimeters (Landauer, Inc., Glenwood, IL), which were read with a MicroStar reader (Landauer, Inc., Glenwood, IL). Dose to the OSLDs was delivered by 6 MV x-rays. NanoDots with various intrinsic sensitivities were irradiated in numerous phantoms that had geometric shapes of cylinders, rectangles, and a cube. Results: No angular dependence was seen in cylindrical phantoms, cubic phantoms, or rectangular phantoms with a thickness to width ratio of 0.3 or 1.5. An angular dependence of 1% was observed in rectangular phantoms with a thickness to width of 0.433–0.633. A group of nanoDots had sensitive layers with mass density of 2.42–2.58 g/cm{sup 3} and relative sensitivity of 0.92–1.09 and no difference in their angular dependence. Within experimental uncertainty, nanoDot measurements agree with a parallel-plate ion chamber at a depth of maximum dose. Conclusions: When irradiated in cylindrical, rectangular, and cubic phantoms, nanoDots show a maximum angular dependence of 1% or less at an incidence angle of 90°. For a sample of 78 new nanoDots, the range of their relative intrinsic sensitivity is 0.92–1.09. For a sample of ten nanoDots, on average, the mass in the sensitive layer is 73.1% Al{sub 2}O{sub 3}:C and 26.9% polyester. The mass density of the sensitive layer of a nanoDot disc is between 2.42 and 2.58 g/cm{sup 3}. The angular dependence is not related to Al{sub 2}O{sub 3}:C loading of the nanoDot disc. The nanoDot at the depth of maximum dose has no more angular dependence than a parallel-plate ion chamber.

  7. Short Communication: Rheological properties of blood serum of rats after irradiation with different gamma radiation doses in vivo.

    PubMed

    Abdelhalim, Mohamed Anwar K; Moussa, Sherif Aa; Ms, Al-Ayed

    2016-01-01

    The blood serum rheological properties open the door to find suitable radio-protectors and convenient therapy for many cases of radiation exposure. The present study aimed to investigate the rheological properties of rat blood serum at wide range of shear rates after whole body irradiation with different gamma radiation doses in vivo. Healthy male rats were divided into five groups; one control group and 4 irradiated groups. The irradiation process was carried out using Co60 source with dose rate of 0.883cG/sec. Several rheological parameters were measured using Brookfield LVDV-III Programmable rheometer. A significant increase in viscosity and shear stress was observed with 25 and 50Gy corresponding to each shear rate compared with the control; while a significant decrease observed with 75 and 100Gy. The viscosity exhibited a Non-Newtonian behaviour with the shear rate while shear stress values were linearly related with shear rate. The decrease in blood viscosity might be attributed to changes in molecular weight, pH sensitivity and protein structure. The changes in rheological properties of irradiated rats' blood serum might be attributed to destruction changes in the haematological and dimensional properties of rats' blood products. PMID:27005501

  8. Effect of different doses of monosodium glutamate on the thyroid follicular cells of adult male albino rats: a histological study

    PubMed Central

    Khalaf, Hanaa A; Arafat, Eetmad A

    2015-01-01

    Monosodium glutamate (MSG) is a major flavor enhancer used as a food additive. The present study investigates the effects of different doses of MSG on the morphometric and histological changes of the thyroid gland. 28 male albino rats were used. The rats were divided into four groups: group I control, group II, III and IV treated with MSG (0.25 g/kg, 3 g/kg, 6 g/kg daily for one month) respectively. The thyroid glands were dissected out and prepared for light and electron microscopic examination. Light microscopic examination of thyroid gland of group II revealed increase in follicular epithelial height. Groups III & IV showed decrease in the follicular diameter and irregularity in the shape of some follicles with discontinuity of basement membrane. Follicular hyperplasia was detected in some follicles with appearance of multiple pyknotic nuclei in follicular and interfollicular cells and multiple exfoliated cells in the colloid. In addition, areas of loss of follicular pattern were appeared in group IV. Immunohistochemical examination of BCL2 immunoexpression of the thyroid glands of groups III & IV reveals weak positive reaction in the follicular cells cytoplasm. Ultrathin sections examination of groups III & IV revealed follicular cells with irregular hyperchromatic nuclei, marked dilatation of rER and increased lysosomes with areas of short or lost apical microvilli. In addition, vacuolation of mitochondria was detected in group IV. The results displayed that MSG even at low doses is capable of producing alterations in the body weights and thyroid tissue function and histology. PMID:26884820

  9. Assessment of different doses of N applied to a melon crop in the quality of groundwater: environmental impact indexes.

    NASA Astrophysics Data System (ADS)

    Castellanos, M. T.; Cartagena, M. C.; Ribas, F.; Cabello, M. J.; Arce, A.; Tarquis, A. M.

    2010-05-01

    Provided that the intensive use of N in agricultural systems has negatively impacted environmental quality, because a higher fertilization requirements of the crop to make the nitrate leached into the aquifer contaminating, as well as increasing their presence on the ground resulting in a time of intercropping nitrates washing with the arrival of rains. It's necessary to know the N management to reduce the pollution risks and may lead the higher production with the fewer economic cost, environmental and health. The aim of this study was to asses how different doses of nitrogen applied to a melon crop affected the quality of groundwater. The doses of N applied ranged between 11 and 393 kg ha-1. Several indexes, based in N leaching consequence of the agricultural practice, were calculated and provided an essential tool for knowing the risks of groundwater pollution with the practices used. Drinking water impact, irrigation water management impact and environmental impact indexes were obtained during four years in a vulnerable area of the centre of Spain. Acknowledgements: This project has been supported by INIA-RTA04-111

  10. Repair rates of DNA double-strand breaks under different doses of proton and γ-ray irradiation

    NASA Astrophysics Data System (ADS)

    Wu, Jingwen; Fu, Qibin; Quan, Yi; Wang, Weikang; Mei, Tao; Li, Jia; Yang, Gen; Ren, Xiaotang; Xue, Jianming; Wang, Yugang

    2012-04-01

    It is known that DNA double-strand breaks (DSBs), which can be induced by a variety of treatments including ionizing radiation (IR), can cause most deleterious consequences among all kinds of DNA lesions. However, it is still under debate about whether DSBs repair is equally efficient after low and high-LET radiation, especially the basic biological responses after exposure to high-LET particles. In present study, synchronous fibroblast normal Human lung fibroblast (NHLF) cells were irradiated with graded doses of proton and γ-ray. Then γ-H2AX foci assay was used to monitor DSBs induction and repair at 0.5, 1, 2, 4, and 18 h post irradiation. The results showed that the γ-ray irradiation could produce more γ-H2AX foci than proton irradiation at the same dose. However, compared to low LET radiation with γ-ray, the results also showed a much slower DSBs repair rate after high LET radiation with protons, suggesting that the cellular ability to eliminate DSBs after low and high-LET ionizing radiation is quite different.

  11. Evaluation of radiation dose of triple rule-out coronary angiography protocols with different scan length using 256-slice CT

    NASA Astrophysics Data System (ADS)

    Tsai, Chia-Jung; Lee, Jason J. S.; Chen, Liang-Kuang; Mok, Greta S. P.; Hsu, Shih-Ming; Wu, Tung-Hsin

    2011-10-01

    Triple rule-out coronary CT angiography (TRO-CTA) is a new approach for providing noninvasive visualization of coronary arteries with simultaneous evaluation of pulmonary arteries, thoracic aorta and other intrathoracic structures. The increasing use of TRO-CTA examination with longer scan length is associated with the concerns about radiation dose and their corresponding cancer risk. The purpose of this study is to evaluate organ dose and effective dose for the TRO-CTA examination with 2 scan lengths: TRO std and TRO ext, using 256-slice CT. TRO-CTA examinations were performed on a 256-slice CT scanner without ECG-based tube current modulation. Absorbed organ doses were measured using an anthropomorphic phantom and thermal-luminance dosimeters (TLDs). Effective dose was determined by taking a sum of the measured absorbed organ doses multiplied with the tissue weighting factor based on ICRP-103, and compared to that calculated using the dose-length product (DLP) method. We obtained high organ doses in the thyroid, esophagus, breast, heart and lung in both TRO-CTA protocols. Effective doses of the TRO std and TRO ext protocols with the phantom method were 26.37 and 42.49 mSv, while those with the DLP method were 19.68 and 38.96 mSv, respectively. Our quantitative dose information establishes a relationship between radiation dose and scanning length, and can provide a practical guidance to best clinical practice.

  12. Comparison of two different dose regimens of nedocromil sodium with placebo in the management of childhood asthma.

    PubMed

    Sekerel, B E; Saraçlar, Y; Etikan, I; Kalayci, O

    1999-01-01

    According to the recent guidelines, persistent asthma requires daily antiinflammatory treatment with either nedocromil sodium, cromolyn sodium or inhaled corticosteroids. In choosing the most appropriate drug, it is wise to weigh the therapeutic advantages against possible side effects, particularly in patients at the milder end of disease spectrum and in children. Cromolyn sodium and nedocromil sodium both have strong safety profiles, and nedocromil sodium has been reported to have a broader spectrum of efficacy than cromolyn sodium. In an attempt to provide data for the efficacy of two different dose regimens of inhaled nedocromil sodium in childhood asthma, a placebo-controlled, randomized, double-blind, double-dummy, parallel group study was conducted in 38 subjects with mild to moderate persistent asthma. After a 2-week run-in period, patients were randomly allocated into one of the three study groups and treated with either placebo or with two times daily (4 mg b.i.d.) or four times daily (4 mg q.i.d.) regimens of inhaled nedocromil sodium for 8 weeks. Symptom scores, bronchodilator requirements, FEV1, daily PEFs and methacholine hyperreactivity were evaluated at study entry, before randomization and at weeks 4 and 8 of treatment. In the four times daily treatment group, slight but significant increases were observed in FEV1, peak expiratory flows and symptom scores (p < 0.05 for each). However, there was no significant change in methacholine hyperreactivity and bronchodilator requirement. In the two times dose regimen and placebo groups, there were no improvements in any of the variables. The compliance, measured as the reduced weight of the canisters, was low, but was not different between the two nedocromil sodium treatment groups. The four times daily regimen of nedocromil sodium was effective in improving control of mild to moderate persistent asthma in children, whereas the two times daily regimen failed.

  13. Why to compare absolute numbers of mitochondria.

    PubMed

    Schmitt, Sabine; Schulz, Sabine; Schropp, Eva-Maria; Eberhagen, Carola; Simmons, Alisha; Beisker, Wolfgang; Aichler, Michaela; Zischka, Hans

    2014-11-01

    Prompted by pronounced structural differences between rat liver and rat hepatocellular carcinoma mitochondria, we suspected these mitochondrial populations to differ massively in their molecular composition. Aiming to reveal these mitochondrial differences, we came across the issue on how to normalize such comparisons and decided to focus on the absolute number of mitochondria. To this end, fluorescently stained mitochondria were quantified by flow cytometry. For rat liver mitochondria, this approach resulted in mitochondrial protein contents comparable to earlier reports using alternative methods. We determined similar protein contents for rat liver, heart and kidney mitochondria. In contrast, however, lower protein contents were determined for rat brain mitochondria and for mitochondria from the rat hepatocellular carcinoma cell line McA 7777. This result challenges mitochondrial comparisons that rely on equal protein amounts as a typical normalization method. Exemplarily, we therefore compared the activity and susceptibility toward inhibition of complex II of rat liver and hepatocellular carcinoma mitochondria and obtained significant discrepancies by either normalizing to protein amount or to absolute mitochondrial number. Importantly, the latter normalization, in contrast to the former, demonstrated a lower complex II activity and higher susceptibility toward inhibition in hepatocellular carcinoma mitochondria compared to liver mitochondria. These findings demonstrate that solely normalizing to protein amount may obscure essential molecular differences between mitochondrial populations.

  14. SU-E-I-57: Evaluation and Optimization of Effective-Dose Using Different Beam-Hardening Filters in Clinical Pediatric Shunt CT Protocol

    SciTech Connect

    Gill, K; Aldoohan, S; Collier, J

    2014-06-01

    Purpose: Study image optimization and radiation dose reduction in pediatric shunt CT scanning protocol through the use of different beam-hardening filters Methods: A 64-slice CT scanner at OU Childrens Hospital has been used to evaluate CT image contrast-to-noise ratio (CNR) and measure effective-doses based on the concept of CT dose index (CTDIvol) using the pediatric head shunt scanning protocol. The routine axial pediatric head shunt scanning protocol that has been optimized for the intrinsic x-ray tube filter has been used to evaluate CNR by acquiring images using the ACR approved CT-phantom and radiation dose CTphantom, which was used to measure CTDIvol. These results were set as reference points to study and evaluate the effects of adding different filtering materials (i.e. Tungsten, Tantalum, Titanium, Nickel and Copper filters) to the existing filter on image quality and radiation dose. To ensure optimal image quality, the scanner routine air calibration was run for each added filter. The image CNR was evaluated for different kVps and wide range of mAs values using above mentioned beam-hardening filters. These scanning protocols were run under axial as well as under helical techniques. The CTDIvol and the effective-dose were measured and calculated for all scanning protocols and added filtration, including the intrinsic x-ray tube filter. Results: Beam-hardening filter shapes energy spectrum, which reduces the dose by 27%. No noticeable changes in image low contrast detectability Conclusion: Effective-dose is very much dependent on the CTDIVol, which is further very much dependent on beam-hardening filters. Substantial reduction in effective-dose is realized using beam-hardening filters as compare to the intrinsic filter. This phantom study showed that significant radiation dose reduction could be achieved in CT pediatric shunt scanning protocols without compromising in diagnostic value of image quality.

  15. LDL-cholesterol-lowering effect of plant sterols and stanols across different dose ranges: a meta-analysis of randomised controlled studies.

    PubMed

    Ras, Rouyanne T; Geleijnse, Johanna M; Trautwein, Elke A

    2014-07-28

    Phytosterols (PS, comprising plant sterols and plant stanols) have been proven to lower LDL-cholesterol concentrations. The dose-response relationship for this effect has been evaluated in several meta-analyses by calculating averages for different dose ranges or by applying continuous dose-response functions. Both approaches have advantages and disadvantages. So far, the calculation of averages for different dose ranges has not been done for plant sterols and stanols separately. The objective of the present meta-analysis was to investigate the combined and separate effects of plant sterols and stanols when classified into different dose ranges. Studies were searched and selected based on predefined criteria. Relevant data were extracted. Average LDL-cholesterol effects were calculated when studies were categorised by dose, according to random-effects models while using the variance as weighing factor. This was done for plant sterols and stanols combined and separately. In total, 124 studies (201 strata) were included. Plant sterols and stanols were administered in 129 and fifty-nine strata, respectively; the remaining used a mix of both. The average PS dose was 2.1 (range 0.2-9.0) g/d. PS intakes of 0.6-3.3 g/d were found to gradually reduce LDL-cholesterol concentrations by, on average, 6-12%. When plant sterols and stanols were analysed separately, clear and comparable dose-response relationships were observed. Studies carried out with PS doses exceeding 4 g/d were not pooled, as these were scarce and scattered across a wide range of doses. In conclusion, the LDL-cholesterol-lowering effect of both plant sterols and stanols continues to increase up to intakes of approximately 3 g/d to an average effect of 12%.

  16. Absolute rate theories of epigenetic stability

    NASA Astrophysics Data System (ADS)

    Walczak, Aleksandra M.; Onuchic, José N.; Wolynes, Peter G.

    2005-12-01

    Spontaneous switching events in most characterized genetic switches are rare, resulting in extremely stable epigenetic properties. We show how simple arguments lead to theories of the rate of such events much like the absolute rate theory of chemical reactions corrected by a transmission factor. Both the probability of the rare cellular states that allow epigenetic escape and the transmission factor depend on the rates of DNA binding and unbinding events and on the rates of protein synthesis and degradation. Different mechanisms of escape from the stable attractors occur in the nonadiabatic, weakly adiabatic, and strictly adiabatic regimes, characterized by the relative values of those input rates. rate theory | stochastic gene expression | gene switches

  17. Characterization of the DARA solar absolute radiometer

    NASA Astrophysics Data System (ADS)

    Finsterle, W.; Suter, M.; Fehlmann, A.; Kopp, G.

    2011-12-01

    The Davos Absolute Radiometer (DARA) prototype is an Electrical Substitution Radiometer (ESR) which has been developed as a successor of the PMO6 type on future space missions and ground based TSI measurements. The DARA implements an improved thermal design of the cavity detector and heat sink assembly to minimize air-vacuum differences and to maximize thermal symmetry of measuring and compensating cavity. The DARA also employs an inverted viewing geometry to reduce internal stray light. We will report on the characterization and calibration experiments which were carried out at PMOD/WRC and LASP (TRF).

  18. The AFGL absolute gravity program

    NASA Technical Reports Server (NTRS)

    Hammond, J. A.; Iliff, R. L.

    1978-01-01

    A brief discussion of the AFGL's (Air Force Geophysics Laboratory) program in absolute gravity is presented. Support of outside work and in-house studies relating to gravity instrumentation are discussed. A description of the current transportable system is included and the latest results are presented. These results show good agreement with measurements at the AFGL site by an Italian system. The accuracy obtained by the transportable apparatus is better than 0.1 microns sq sec 10 microgal and agreement with previous measurements is within the combined uncertainties of the measurements.

  19. Familial Aggregation of Absolute Pitch

    PubMed Central

    Baharloo, Siamak; Service, Susan K.; Risch, Neil; Gitschier, Jane; Freimer, Nelson B.

    2000-01-01

    Absolute pitch (AP) is a behavioral trait that is defined as the ability to identify the pitch of tones in the absence of a reference pitch. AP is an ideal phenotype for investigation of gene and environment interactions in the development of complex human behaviors. Individuals who score exceptionally well on formalized auditory tests of pitch perception are designated as “AP-1.” As described in this report, auditory testing of siblings of AP-1 probands and of a control sample indicates that AP-1 aggregates in families. The implications of this finding for the mapping of loci for AP-1 predisposition are discussed. PMID:10924408

  20. A Special Application of Absolute Value Techniques in Authentic Problem Solving

    ERIC Educational Resources Information Center

    Stupel, Moshe

    2013-01-01

    There are at least five different equivalent definitions of the absolute value concept. In instances where the task is an equation or inequality with only one or two absolute value expressions, it is a worthy educational experience for learners to solve the task using each one of the definitions. On the other hand, if more than two absolute value…

  1. Constraint on Absolute Accuracy of Metacomprehension Assessments: The Anchoring and Adjustment Model vs. the Standards Model

    ERIC Educational Resources Information Center

    Kwon, Heekyung

    2011-01-01

    The objective of this study is to provide a systematic account of three typical phenomena surrounding absolute accuracy of metacomprehension assessments: (1) the absolute accuracy of predictions is typically quite low; (2) there exist individual differences in absolute accuracy of predictions as a function of reading skill; and (3) postdictions…

  2. Species differences in toxicokinetic parameters of glycidol after a single dose of glycidol or glycidol linoleate in rats and monkeys.

    PubMed

    Wakabayashi, Ken-ichi; Kurata, Yoshimasa; Harada, Tomoo; Tamaki, Yasushi; Nishiyama, Naohiro; Kasamatsu, Toshio

    2012-01-01

    Glycidol fatty acid esters (GEs) have been identified as contaminants in refined edible oils. Although the possible release of glycidol (G) from GEs is a concern, little is known about the conversion of GEs to G in the human body. This study addressed the toxicokinetics of glycidol linoleate (GL) and G in male Crl:CD(SD) rats and cynomolgus monkeys. Equimolar amounts of GL (341 mg/kg) or G (75 mg/kg) were administered by gavage to each animal. G was found in both species after the G and GL administration, while plasma GL concentrations were below the lower limit of quantification (5 ng/ml) in both species. In rats, the administration of GL or G produced similar concentration-time profiles for G. In monkeys, the C(max) and AUC values after GL administration were significantly lower than those after G administration. The oral bioavailability of G in monkeys (34.3%) was remarkably lower than that in rats (68.8%) at 75 mg/kg G administration. In addition, plasma G concentrations after oral administration at three lower doses of GL or G were measured in both species. In monkeys, G was detected only at the highest dose of G. In contrast, the rats exhibited similar plasma G concentration-time profiles after GL or G administration with significantly higher G levels than those in monkeys. In conclusion, these results indicate that there are remarkable species differences in the toxicokinetics of GEs and G between rodents and primates, findings that should be considered when assessing the human risk of GEs.

  3. Microscopic examination on cytological changes in Allium cepa and shift in phytoplankton population at different doses of Atrazine

    NASA Astrophysics Data System (ADS)

    Ghosh, Nabarun; Finger, Kristen; Usnick, Samantha; Rogers, William J.; Das, A. B.; Smith, Don W.

    2010-06-01

    Atrazine is a wide-range herbicide. For over 50 years, atrazine has been used as a selective broadleaf herbicide in many capacities, from pre-plant to pre-emergence to post-emergence, depending on the crop and application. Currently, 96% of all atrazine used is for commercial applications in fields for the control of broadleaf and grassy weeds in crops such as sorghum, corn, sugarcane, pineapple and for the control of undesirable weeds in rangeland. Many panhandle wells have also detected atrazine in samples taken. The concern for the public is the long-term effect of atrazine with its increasing popularity, and the impact on public health. We investigated the effect of different concentrations of atrazine on Allium cepa (onion), a standard plant test system. We established a control with the Allium bulbs grown on hydroponics culture. Varying concentrations of atrazine was used on the standard plant test system, Allium cepa grown hydroponically. The mitotic indices varied and with higher doses, we observed various chromosomal abnormalities including sticky bridges, early and late separations, and lag chromosomes with higher doses of treatments. In the second part of the experiment, 0.1ppb, 1ppb, 10ppb, and 100ppb concentrations of atrazine were applied to established phytoplankton cultures from the Lake Tanglewood, Texas. Study with a Sedgwick-Rafter counter, a BX-40 Olympus microscope with DP-70 camera revealed a gradual shift in the phytoplankton community from obligatory to facultative autotroph and finally to a parasitic planktonic community. This explains the periodic fish kill in the lakes after applications of atrazine in crop fields.

  4. Polymer gel dosimeters with reduced toxicity: a preliminary investigation of the NMR and optical dose response using different monomers

    NASA Astrophysics Data System (ADS)

    Senden, R. J.; DeJean, P.; McAuley, K. B.; Schreiner, L. J.

    2006-07-01

    In this work, three new polymer gel dosimeter recipes were investigated that may be more suitable for widespread applications than polyacrylamide gel dosimeters, since the extremely toxic acrylamide has been replaced with the less harmful monomers N-isopropylacrylamide (NIPAM), diacetone acrylamide and N-vinylformamide. The new gel dosimeters studied contained gelatin (5 wt%), monomer (3 wt%), N,N'-methylene-bis-acrylamide crosslinker (3 wt%) and tetrakis (hydroxymethyl) phosphonium chloride antioxidant (10 mM). The NMR response (R2) of the dosimeters was analysed for conditions of varying dose, dose rate, time post-irradiation, and temperature during irradiation and scanning. It was shown that the dose-response behaviour of the NIPAM/Bis gel dosimeter is comparable to that of normoxic polyacrylamide gel (PAGAT) in terms of high dose-sensitivity and low dependence on dose rate and irradiation temperature, within the ranges considered. The dose-response (R2) of NIPAM/Bis appears to be linear over a greater dose range than the PAGAT gel dosimeter. The effects of time post-irradiation (temporal instability) and temperature during NMR scanning on the R2 response were more significant for NIPAM/Bis dosimeters. Diacetone acrylamide and N-vinylformamide gel dosimeters possessed considerably lower dose-sensitivities. The optical dose-response, measured in terms of the attenuation coefficient for each polymer gel dosimeter, showed potential for the use of optical imaging techniques in future studies.

  5. Polymer gel dosimeters with reduced toxicity: a preliminary investigation of the NMR and optical dose-response using different monomers.

    PubMed

    Senden, R J; De Jean, P; McAuley, K B; Schreiner, L J

    2006-07-21

    In this work, three new polymer gel dosimeter recipes were investigated that may be more suitable for widespread applications than polyacrylamide gel dosimeters, since the extremely toxic acrylamide has been replaced with the less harmful monomers N-isopropylacrylamide (NIPAM), diacetone acrylamide and N-vinylformamide. The new gel dosimeters studied contained gelatin (5 wt%), monomer (3 wt%), N,N'-methylene-bis-acrylamide crosslinker (3 wt%) and tetrakis (hydroxymethyl) phosphonium chloride antioxidant (10 mM). The NMR response (R2) of the dosimeters was analysed for conditions of varying dose, dose rate, time post-irradiation, and temperature during irradiation and scanning. It was shown that the dose-response behaviour of the NIPAM/Bis gel dosimeter is comparable to that of normoxic polyacrylamide gel (PAGAT) in terms of high dose-sensitivity and low dependence on dose rate and irradiation temperature, within the ranges considered. The dose-response (R2) of NIPAM/Bis appears to be linear over a greater dose range than the PAGAT gel dosimeter. The effects of time post-irradiation (temporal instability) and temperature during NMR scanning on the R2 response were more significant for NIPAM/Bis dosimeters. Diacetone acrylamide and N-vinylformamide gel dosimeters possessed considerably lower dose-sensitivities. The optical dose-response, measured in terms of the attenuation coefficient for each polymer gel dosimeter, showed potential for the use of optical imaging techniques in future studies. PMID:16825731

  6. No difference in frontal cortical activity during an executive functioning task after acute doses of aripiprazole and haloperidol

    PubMed Central

    Bolstad, Ingeborg; Andreassen, Ole A.; Groote, Inge R.; Haatveit, Beathe; Server, Andres; Jensen, Jimmy

    2015-01-01

    Background: Aripiprazole is an atypical antipsychotic drug that is characterized by partial dopamine D2 receptor agonism. Its pharmacodynamic profile is proposed to be beneficial in the treatment of cognitive impairment, which is prevalent in psychotic disorders. This study compared brain activation characteristics produced by aripiprazole with that of haloperidol, a typical D2 receptor antagonist, during a task targeting executive functioning. Methods: Healthy participants received an acute oral dose of haloperidol, aripiprazole or placebo before performing an executive functioning task while blood-oxygen-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) was carried out. Results: There was a tendency towards reduced performance in the aripiprazole group compared to the two other groups. The image analysis yielded a strong task-related BOLD-fMRI response within each group. An uncorrected between-group analysis showed that aripiprazole challenge resulted in stronger activation in the frontal and temporal gyri and the putamen compared with haloperidol challenge, but after correcting for multiple testing there was no significant group difference. Conclusion: No significant group differences between aripiprazole and haloperidol in frontal cortical activation were obtained when corrected for multiple comparisons. This study is registered in ClinicalTrials.gov (identifier: 2009-016222-14).1 PMID:26074803

  7. Absolute Antenna Calibration at the US National Geodetic Survey

    NASA Astrophysics Data System (ADS)

    Mader, G. L.; Bilich, A. L.

    2012-12-01

    Geodetic GNSS applications routinely demand millimeter precision and extremely high levels of accuracy. To achieve these accuracies, measurement and instrument biases at the centimeter to millimeter level must be understood. One of these biases is the antenna phase center, the apparent point of signal reception for a GNSS antenna. It has been well established that phase center patterns differ between antenna models and manufacturers; additional research suggests that the addition of a radome or the choice of antenna mount can significantly alter those a priori phase center patterns. For the more demanding GNSS positioning applications and especially in cases of mixed-antenna networks, it is all the more important to know antenna phase center variations as a function of both elevation and azimuth in the antenna reference frame and incorporate these models into analysis software. Determination of antenna phase center behavior is known as "antenna calibration". Since 1994, NGS has computed relative antenna calibrations for more than 350 antennas. In recent years, the geodetic community has moved to absolute calibrations - the IGS adopted absolute antenna phase center calibrations in 2006 for use in their orbit and clock products, and NGS's CORS group began using absolute antenna calibration upon the release of the new CORS coordinates in IGS08 epoch 2005.00 and NAD 83(2011,MA11,PA11) epoch 2010.00. Although NGS relative calibrations can be and have been converted to absolute, it is considered best practice to independently measure phase center characteristics in an absolute sense. Consequently, NGS has developed and operates an absolute calibration system. These absolute antenna calibrations accommodate the demand for greater accuracy and for 2-dimensional (elevation and azimuth) parameterization. NGS will continue to provide calibration values via the NGS web site www.ngs.noaa.gov/ANTCAL, and will publish calibrations in the ANTEX format as well as the legacy ANTINFO

  8. SU-E-T-491: Importance of Energy Dependent Protons Per MU Calibration Factors in IMPT Dose Calculations Using Monte Carlo Technique

    SciTech Connect

    Randeniya, S; Mirkovic, D; Titt, U; Guan, F; Mohan, R

    2014-06-01

    Purpose: In intensity modulated proton therapy (IMPT), energy dependent, protons per monitor unit (MU) calibration factors are important parameters that determine absolute dose values from energy deposition data obtained from Monte Carlo (MC) simulations. Purpose of this study was to assess the sensitivity of MC-computed absolute dose distributions to the protons/MU calibration factors in IMPT. Methods: A “verification plan” (i.e., treatment beams applied individually to water phantom) of a head and neck patient plan was calculated using MC technique. The patient plan had three beams; one posterior-anterior (PA); two anterior oblique. Dose prescription was 66 Gy in 30 fractions. Of the total MUs, 58% was delivered in PA beam, 25% and 17% in other two. Energy deposition data obtained from the MC simulation were converted to Gy using energy dependent protons/MU calibrations factors obtained from two methods. First method is based on experimental measurements and MC simulations. Second is based on hand calculations, based on how many ion pairs were produced per proton in the dose monitor and how many ion pairs is equal to 1 MU (vendor recommended method). Dose distributions obtained from method one was compared with those from method two. Results: Average difference of 8% in protons/MU calibration factors between method one and two converted into 27 % difference in absolute dose values for PA beam; although dose distributions preserved the shape of 3D dose distribution qualitatively, they were different quantitatively. For two oblique beams, significant difference in absolute dose was not observed. Conclusion: Results demonstrate that protons/MU calibration factors can have a significant impact on absolute dose values in IMPT depending on the fraction of MUs delivered. When number of MUs increases the effect due to the calibration factors amplify. In determining protons/MU calibration factors, experimental method should be preferred in MC dose calculations

  9. Optimal dose selection of N-methyl-N-nitrosourea for the rat comet assay to evaluate DNA damage in organs with different susceptibility to cytotoxicity.

    PubMed

    Kitamoto, Sachiko; Matsuyama, Ryoko; Uematsu, Yasuaki; Ogata, Keiko; Ota, Mika; Yamada, Toru; Miyata, Kaori; Funabashi, Hitoshi; Saito, Koichi

    2015-07-01

    The in vivo rodent alkaline comet assay (comet assay) is a promising technique to evaluate DNA damage in vivo. However, there is no agreement on a method to evaluate DNA damage in organs where cytotoxicity is observed. As a part of the Japanese Center for the Validation of Alternative Methods (JaCVAM)-initiative international validation study of the comet assay, we examined DNA damage in the liver, stomach, and bone marrow of rats given three oral doses of N-methyl-N-nitrosourea (MNU) up to the maximum tolerated dose based on systemic toxicity. MNU significantly increased the % tail DNA in all the organs. Histopathological analysis showed no cytotoxic effect on the liver, indicating clearly that MNU has a genotoxic potential in the liver. In the stomach, however, the cytotoxic effects were very severe at systemically non-toxic doses. Low-dose MNU significantly increased the % tail DNA even at a non-cytotoxic dose, indicating that MNU has a genotoxic potential also in the stomach. Part of the DNA damage at cytotoxic doses was considered to be a secondary effect of severe cell damage. In the bone marrow, both the % tail DNA and incidence of micronucleated polychromatic erythrocytes significantly increased at non-hematotoxic doses, which were different from the non-cytotoxic doses for liver and stomach. These findings indicate that an optimal dose for detecting DNA damage may vary among organs and that careful attention is required to select an optimum dose for the comet assay based on systemic toxicity such as mortality and clinical observations. The present study shows that when serious cytotoxicity is suggested by increased % hedgehogs in the comet assay, histopathological examination should be included for the evaluation of a positive response.

  10. Metabolomic profiling of urine samples from mice exposed to protons reveals radiation quality and dose specific differences.

    PubMed

    Laiakis, Evagelia C; Trani, Daniela; Moon, Bo-Hyun; Strawn, Steven J; Fornace, Albert J

    2015-04-01

    As space travel is expanding to include private tourism and travel beyond low-Earth orbit, so is the risk of exposure to space radiation. Galactic cosmic rays and solar particle events have the potential to expose space travelers to significant doses of radiation that can lead to increased cancer risk and other adverse health consequences. Metabolomics has the potential to assess an individual's risk by exploring the metabolic perturbations in a biofluid or tissue. In this study, C57BL/6 mice were exposed to 0.5 and 2 Gy of 1 GeV/nucleon of protons and the levels of metabolites were evaluated in urine at 4 h after radiation exposure through liquid chromatography coupled to time-of-flight mass spectrometry. Significant differences were identified in metabolites that map to the tricarboxylic acid (TCA) cycle and fatty acid metabolism, suggesting that energy metabolism is severely impacted after exposure to protons. Additionally, various pathways of amino acid metabolism (tryptophan, tyrosine, arginine and proline and phenylalanine) were affected with potential implications for DNA damage repair and cognitive impairment. Finally, presence of products of purine and pyrimidine metabolism points to direct DNA damage or increased apoptosis. Comparison of these metabolomic data to previously published data from our laboratory with gamma radiation strongly suggests a more pronounced effect on metabolism with protons. This is the first metabolomics study with space radiation in an easily accessible biofluid such as urine that further investigates and exemplifies the biological differences at early time points after exposure to different radiation qualities.

  11. Metabolomic profiling of urine samples from mice exposed to protons reveals radiation quality and dose specific differences.

    PubMed

    Laiakis, Evagelia C; Trani, Daniela; Moon, Bo-Hyun; Strawn, Steven J; Fornace, Albert J

    2015-04-01

    As space travel is expanding to include private tourism and travel beyond low-Earth orbit, so is the risk of exposure to space radiation. Galactic cosmic rays and solar particle events have the potential to expose space travelers to significant doses of radiation that can lead to increased cancer risk and other adverse health consequences. Metabolomics has the potential to assess an individual's risk by exploring the metabolic perturbations in a biofluid or tissue. In this study, C57BL/6 mice were exposed to 0.5 and 2 Gy of 1 GeV/nucleon of protons and the levels of metabolites were evaluated in urine at 4 h after radiation exposure through liquid chromatography coupled to time-of-flight mass spectrometry. Significant differences were identified in metabolites that map to the tricarboxylic acid (TCA) cycle and fatty acid metabolism, suggesting that energy metabolism is severely impacted after exposure to protons. Additionally, various pathways of amino acid metabolism (tryptophan, tyrosine, arginine and proline and phenylalanine) were affected with potential implications for DNA damage repair and cognitive impairment. Finally, presence of products of purine and pyrimidine metabolism points to direct DNA damage or increased apoptosis. Comparison of these metabolomic data to previously published data from our laboratory with gamma radiation strongly suggests a more pronounced effect on metabolism with protons. This is the first metabolomics study with space radiation in an easily accessible biofluid such as urine that further investigates and exemplifies the biological differences at early time points after exposure to different radiation qualities. PMID:25768838

  12. Low-Dose Topical 5-Aminolevulinic Acid Photodynamic Therapy in the Treatment of Different Severity of Acne Vulgaris.

    PubMed

    Tao, Shi-Qin; Li, Fei; Cao, Lei; Xia, Ru-Shan; Fan, Hua; Fan, Ying; Sun, Hui; Jing, Cheng; Yang, Li-Jia

    2015-12-01

    The objective of this article is to investigate the effectiveness and safety of photodynamic therapy (PDT) with 3.6 % topical aminolevulinic acid (ALA) and a short incubation time with red light in moderate to severe acne. One hundred and thirty-six patients with moderate to severe acne were treated with 3.6 % topical ALA-PDT for three sessions with an interval of 2 weeks. Patients were evaluated for efficacy and safety on week 2, 4, 6, 8, and 12 after the initial treatment. Most patients showed apparent clearance of acne lesions at the treated site after three sessions. The effective treatment rates were increased after the multiple therapies. The clinical outcomes are the best at 4 weeks after the final treatment. The total effectiveness rate and cure rate of the low-dose ALA-PDT procedure is 92.65 and 47.06 %, respectively. Thirty-one patients and nineteen patients showed apparent exacerbation of acne lesions before the 2nd and 3rd treatment, respectively, but all of them showed good or excellent improvement after a three-course treatment. A few patients showed mild relapse including papules and comedos at 8 weeks after the final treatment. No significant differences are found in the effects of different acne severity and different genders. Adverse reactions are mild and transient. A 3.6 % topical ALA-PDT with a short time incubation with red light is a simple and an effective treatment option for moderate to severe acne with mild side effects in Chinese people.

  13. Metabolomic Profiling of Urine Samples from Mice Exposed to Protons Reveals Radiation Quality and Dose Specific Differences

    PubMed Central

    Laiakis, Evagelia C.; Trani, Daniela; Moon, Bo-Hyun; Strawn, Steven J.; Fornace, Albert J.

    2015-01-01

    As space travel is expanding to include private tourism and travel beyond low-Earth orbit, so is the risk of exposure to space radiation. Galactic cosmic rays and solar particle events have the potential to expose space travelers to significant doses of radiation that can lead to increased cancer risk and other adverse health consequences. Metabolomics has the potential to assess an individual’s risk by exploring the metabolic perturbations in a biofluid or tissue. In this study, C57BL/6 mice were exposed to 0.5 and 2 Gy of 1 GeV/nucleon of protons and the levels of metabolites were evaluated in urine at 4 h after radiation exposure through liquid chromatography coupled to time-of-flight mass spectrometry. Significant differences were identified in metabolites that map to the tricarboxylic acid (TCA) cycle and fatty acid metabolism, suggesting that energy metabolism is severely impacted after exposure to protons. Additionally, various pathways of amino acid metabolism (tryptophan, tyrosine, arginine and proline and phenylalanine) were affected with potential implications for DNA damage repair and cognitive impairment. Finally, presence of products of purine and pyrimidine metabolism points to direct DNA damage or increased apoptosis. Comparison of these metabolomic data to previously published data from our laboratory with gamma radiation strongly suggests a more pronounced effect on metabolism with protons. This is the first metabolomics study with space radiation in an easily accessible biofluid such as urine that further investigates and exemplifies the biological differences at early time points after exposure to different radiation qualities. PMID:25768838

  14. Cosmology with negative absolute temperatures

    NASA Astrophysics Data System (ADS)

    Vieira, J. P. P.; Byrnes, Christian T.; Lewis, Antony

    2016-08-01

    Negative absolute temperatures (NAT) are an exotic thermodynamical consequence of quantum physics which has been known since the 1950's (having been achieved in the lab on a number of occasions). Recently, the work of Braun et al. [1] has rekindled interest in negative temperatures and hinted at a possibility of using NAT systems in the lab as dark energy analogues. This paper goes one step further, looking into the cosmological consequences of the existence of a NAT component in the Universe. NAT-dominated expanding Universes experience a borderline phantom expansion (w < ‑1) with no Big Rip, and their contracting counterparts are forced to bounce after the energy density becomes sufficiently large. Both scenarios might be used to solve horizon and flatness problems analogously to standard inflation and bouncing cosmologies. We discuss the difficulties in obtaining and ending a NAT-dominated epoch, and possible ways of obtaining density perturbations with an acceptable spectrum.

  15. Apparatus for absolute pressure measurement

    NASA Technical Reports Server (NTRS)

    Hecht, R. (Inventor)

    1969-01-01

    An absolute pressure sensor (e.g., the diaphragm of a capacitance manometer) was subjected to a superimposed potential to effectively reduce the mechanical stiffness of the sensor. This substantially increases the sensitivity of the sensor and is particularly useful in vacuum gauges. An oscillating component of the superimposed potential induced vibrations of the sensor. The phase of these vibrations with respect to that of the oscillating component was monitored, and served to initiate an automatic adjustment of the static component of the superimposed potential, so as to bring the sensor into resonance at the frequency of the oscillating component. This establishes a selected sensitivity for the sensor, since a definite relationship exists between resonant frequency and sensitivity.

  16. Cosmology with negative absolute temperatures

    NASA Astrophysics Data System (ADS)

    Vieira, J. P. P.; Byrnes, Christian T.; Lewis, Antony

    2016-08-01

    Negative absolute temperatures (NAT) are an exotic thermodynamical consequence of quantum physics which has been known since the 1950's (having been achieved in the lab on a number of occasions). Recently, the work of Braun et al. [1] has rekindled interest in negative temperatures and hinted at a possibility of using NAT systems in the lab as dark energy analogues. This paper goes one step further, looking into the cosmological consequences of the existence of a NAT component in the Universe. NAT-dominated expanding Universes experience a borderline phantom expansion (w < -1) with no Big Rip, and their contracting counterparts are forced to bounce after the energy density becomes sufficiently large. Both scenarios might be used to solve horizon and flatness problems analogously to standard inflation and bouncing cosmologies. We discuss the difficulties in obtaining and ending a NAT-dominated epoch, and possible ways of obtaining density perturbations with an acceptable spectrum.

  17. [Long-term evacuation after the nuclear accident in Fukushima ~Different daily living under low-dose radioactive suffering~].

    PubMed

    Ishikawa, Kazunobu

    2013-01-01

    One year has passed since the Great East Japan Earthquake and the Fukushima No. 1 nuclear power plant accident. Even currently, more than 150,000 evacuees in Fukushima Prefecture are forced to leave their home and to move throughout Japan. Because of the limited space of temporary housing and the weakening of personal ties in local communities, many families need to move and have separate lives. As a consequence, Fukushima has a serious shortage of caregivers for the elderly. There have been more than 1,300 disaster-related deaths due to shock and stress after long-distance drifts from town to town. Most of the victims were the elderly, who collapsed, caught pneumonia, suffered stroke and heart attack. Concerns about the safety of low-dose radiation exposure deprived the elderly of important contact with playing outside with their grandchildren in Fukushima. Fear of invisible radioactive contamination inactivated outdoor activities such as farming, dairy, fishing, gardening, hiking and wild-vegetable/mushroom hunting, although most of these activities have been traditionally supported by the wisdom of the elderly. Several recent questionnaire investigations revealed that older evacuees wish to go home even if the environment has significant contamination. In contrast, more than half of younger generation with small children have a different attitude. Nuclear accident brought serious social pains although it did not acutely hurt our bodies.

  18. [Long-term evacuation after the nuclear accident in Fukushima ~Different daily living under low-dose radioactive suffering~].

    PubMed

    Ishikawa, Kazunobu

    2013-01-01

    One year has passed since the Great East Japan Earthquake and the Fukushima No. 1 nuclear power plant accident. Even currently, more than 150,000 evacuees in Fukushima Prefecture are forced to leave their home and to move throughout Japan. Because of the limited space of temporary housing and the weakening of personal ties in local communities, many families need to move and have separate lives. As a consequence, Fukushima has a serious shortage of caregivers for the elderly. There have been more than 1,300 disaster-related deaths due to shock and stress after long-distance drifts from town to town. Most of the victims were the elderly, who collapsed, caught pneumonia, suffered stroke and heart attack. Concerns about the safety of low-dose radiation exposure deprived the elderly of important contact with playing outside with their grandchildren in Fukushima. Fear of invisible radioactive contamination inactivated outdoor activities such as farming, dairy, fishing, gardening, hiking and wild-vegetable/mushroom hunting, although most of these activities have been traditionally supported by the wisdom of the elderly. Several recent questionnaire investigations revealed that older evacuees wish to go home even if the environment has significant contamination. In contrast, more than half of younger generation with small children have a different attitude. Nuclear accident brought serious social pains although it did not acutely hurt our bodies. PMID:23925101

  19. Differences in rates of decrease of environmental radiation dose rates by ground surface property in Fukushima City after the Fukushima Daiichi nuclear power plant accident.

    PubMed

    Kakamu, Takeyasu; Kanda, Hideyuki; Tsuji, Masayoshi; Kobayashi, Daisuke; Miyake, Masao; Hayakawa, Takehito; Katsuda, Shin-ichiro; Mori, Yayoi; Okouchi, Toshiyasu; Hazama, Akihiro; Fukushima, Tetsuhito

    2013-01-01

    After the Great East Japan Earthquake on 11 March 2011, the environmental radiation dose in Fukushima City increased. On 11 April, 1 mo after the earthquake, the environmental radiation dose rate at various surfaces in the same area differed greatly by surface property. Environmental radiation measurements continue in order to determine the estimated time to 50% reduction in environmental radiation dose rates by surface property in order to make suggestions for decontamination in Fukushima. The measurements were carried out from 11 April to 11 November 2011. Forty-eight (48) measurement points were selected, including four kinds of ground surface properties: grass (13), soil (5), artificial turf (7), and asphalt (23). Environmental radiation dose rate was measured at heights of 100 cm above the ground surface. Time to 50% reduction of environmental radiation dose rates was estimated for each ground surface property. Radiation dose rates on 11 November had decreased significantly compared with those on 11 April for all surface properties. Artificial turf showed the longest time to 50% reduction (544.32 d, standard error: 96.86), and soil showed the shortest (213.20 d, standard error: 35.88). The authors found the environmental radiation dose rate on artificial materials to have a longer 50% reduction time than that on natural materials. These results contribute to determining an order of priority for decontamination after nuclear disasters.

  20. Bioavailability of Pyrene Associated with Suspended Sediment of Different Grain Sizes to Daphnia magna as Investigated by Passive Dosing Devices.

    PubMed

    Zhang, Xiaotian; Xia, Xinghui; Li, Husheng; Zhu, Baotong; Dong, Jianwei

    2015-08-18

    Suspended sediment (SPS) is widely present in rivers around the world. However, the bioavailability of hydrophobic organic compounds (HOCs) associated with SPS is not well understood. In this work, the influence of SPS grain size on the bioavailability of SPS-associated pyrene to Daphnia magna was studied using a passive dosing device, which maintained a constant freely dissolved pyrene concentration (Cfree) in the exposure systems. The immobilization and protein as well as enzymatic activities of Daphnia magna were investigated to study the bioavailability of SPS-associated pyrene. With Cfree of pyrene ranging from 20.0 to 60.0 μg L(-1), the immobilization of Daphnia magna in the presence of 1 g L(-1) SPS was 1.11-2.89 times that in the absence of SPS. The immobilization caused by pyrene associated with different grain size SPS was on the order of 50-100 μm > 0-50 μm > 100-150 μm. When pyrene Cfree was 20.0 μg L(-1), the immobilization caused by pyrene associated with 50-100 μm SPS was 1.42 and 2.43 times that with 0-50 and 100-150 μm SPS, respectively. The protein and enzymatic activities of Daphnia magna also varied with the SPS grain size. The effect of SPS grain size on the bioavailability of SPS-associated pyrene was mainly due to the difference in SPS ingestion by Daphnia magna and SPS composition, especially the organic carbon type, among the three size fractions. This study suggests that not only the concentration but also the size distribution of SPS should be considered for the development of a biological effect database and establishment of water quality criteria for HOCs in natural waters.

  1. Bioavailability of Pyrene Associated with Suspended Sediment of Different Grain Sizes to Daphnia magna as Investigated by Passive Dosing Devices.

    PubMed

    Zhang, Xiaotian; Xia, Xinghui; Li, Husheng; Zhu, Baotong; Dong, Jianwei

    2015-08-18

    Suspended sediment (SPS) is widely present in rivers around the world. However, the bioavailability of hydrophobic organic compounds (HOCs) associated with SPS is not well understood. In this work, the influence of SPS grain size on the bioavailability of SPS-associated pyrene to Daphnia magna was studied using a passive dosing device, which maintained a constant freely dissolved pyrene concentration (Cfree) in the exposure systems. The immobilization and protein as well as enzymatic activities of Daphnia magna were investigated to study the bioavailability of SPS-associated pyrene. With Cfree of pyrene ranging from 20.0 to 60.0 μg L(-1), the immobilization of Daphnia magna in the presence of 1 g L(-1) SPS was 1.11-2.89 times that in the absence of SPS. The immobilization caused by pyrene associated with different grain size SPS was on the order of 50-100 μm > 0-50 μm > 100-150 μm. When pyrene Cfree was 20.0 μg L(-1), the immobilization caused by pyrene associated with 50-100 μm SPS was 1.42 and 2.43 times that with 0-50 and 100-150 μm SPS, respectively. The protein and enzymatic activities of Daphnia magna also varied with the SPS grain size. The effect of SPS grain size on the bioavailability of SPS-associated pyrene was mainly due to the difference in SPS ingestion by Daphnia magna and SPS composition, especially the organic carbon type, among the three size fractions. This study suggests that not only the concentration but also the size distribution of SPS should be considered for the development of a biological effect database and establishment of water quality criteria for HOCs in natural waters. PMID:26199982

  2. Experimental results for absolute cylindrical wavefront testing

    NASA Astrophysics Data System (ADS)

    Reardon, Patrick J.; Alatawi, Ayshah

    2014-09-01

    Applications for Cylindrical and near-cylindrical surfaces are ever-increasing. However, fabrication of high quality cylindrical surfaces is limited by the difficulty of accurate and affordable metrology. Absolute testing of such surfaces represents a challenge to the optical testing community as cylindrical reference wavefronts are difficult to produce. In this paper, preliminary results for a new method of absolute testing of cylindrical wavefronts are presented. The method is based on the merging of the random ball test method with the fiber optic reference test. The random ball test assumes a large number of interferograms of a good quality sphere with errors that are statistically distributed such that the average of the errors goes to zero. The fiber optic reference test utilizes a specially processed optical fiber to provide a clean high quality reference wave from an incident line focus from the cylindrical wave under test. By taking measurements at different rotation and translations of the fiber, an analogous procedure can be employed to determine the quality of the converging cylindrical wavefront with high accuracy. This paper presents and discusses the results of recent tests of this method using a null optic formed by a COTS cylindrical lens and a free-form polished corrector element.

  3. Transient absolute robustness in stochastic biochemical networks.

    PubMed

    Enciso, German A

    2016-08-01

    Absolute robustness allows biochemical networks to sustain a consistent steady-state output in the face of protein concentration variability from cell to cell. This property is structural and can be determined from the topology of the network alone regardless of rate parameters. An important question regarding these systems is the effect of discrete biochemical noise in the dynamical behaviour. In this paper, a variable freezing technique is developed to show that under mild hypotheses the corresponding stochastic system has a transiently robust behaviour. Specifically, after finite time the distribution of the output approximates a Poisson distribution, centred around the deterministic mean. The approximation becomes increasingly accurate, and it holds for increasingly long finite times, as the total protein concentrations grow to infinity. In particular, the stochastic system retains a transient, absolutely robust behaviour corresponding to the deterministic case. This result contrasts with the long-term dynamics of the stochastic system, which eventually must undergo an extinction event that eliminates robustness and is completely different from the deterministic dynamics. The transiently robust behaviour may be sufficient to carry out many forms of robust signal transduction and cellular decision-making in cellular organisms. PMID:27581485

  4. Determination of radionuclides and pathways contributing to cumulative dose

    SciTech Connect

    Napier, B.A.

    1992-12-01

    A series of scoping calculations has been undertaken to evaluate the absolute and relative contributions of different radionuclides and exposure pathways to doses that may have been received by individuals living in the vicinity of the Hanford Site. This scoping calculation (Calculation 004) examined the contributions of numerous radionuclides to cumulative dose via environmental exposures and accumulation in foods. Addressed in this calculation were the contributions to organ and effective dose of infants and adults from (1) air submersion and groundshine external dose, (2) inhalation, (3) ingestion of soil by humans, (4) ingestion of leafy vegetables, (5) ingestion of other vegetables and fruits, (6) ingestion of meat, (7) ingestion of eggs, and (8) ingestion of cows' milk from Feeding Regime 1, as described in calculation 002. This calculation specifically addresses cumulative radiation doses to infants and adults resulting from releases occurring over the period 1945 through 1972.

  5. The Absolute Radiometric Calibration of Space - Sensors.

    NASA Astrophysics Data System (ADS)

    Holm, Ronald Gene

    1987-09-01

    The need for absolute radiometric calibration of space-based sensors will continue to increase as new generations of space sensors are developed. A reflectance -based in-flight calibration procedure is used to determine the radiance reaching the entrance pupil of the sensor. This procedure uses ground-based measurements coupled with a radiative transfer code to characterize the effects the atmosphere has on the signal reaching the sensor. The computed radiance is compared to the digital count output of the sensor associated with the image of a test site. This provides an update to the preflight calibration of the system and a check on the on-board internal calibrator. This calibration procedure was used to perform a series of five calibrations of the Landsat-5 Thematic Mapper (TM). For the 12 measurements made in TM bands 1-3, the RMS variation from the mean as a percentage of the mean is (+OR-) 1.9%, and for measurements in the IR, TM bands 4,5, and 7, the value is (+OR-) 3.4%. The RMS variation for all 23 measurements is (+OR-) 2.8%. The absolute calibration techniques were put to another test with a series of three calibration of the SPOT-1 High Resolution Visible, (HRV), sensors. The ratio, HRV-2/HRV-1, of absolute calibration coefficients compared very well with ratios of histogrammed data obtained when the cameras simultaneously imaged the same ground site. Bands PA, B1 and B3 agreed to within 3%, while band B2 showed a 7% difference. The procedure for performing a satellite calibration was then used to demonstrate how a calibrated satellite sensor can be used to quantitatively evaluate surface reflectance over a wide range of surface features. Predicted reflectance factors were compared to values obtained from aircraft -based radiometer data. This procedure was applied on four dates with two different surface conditions per date. A strong correlation, R('2) = .996, was shown between reflectance values determined from satellite imagery and low-flying aircraft

  6. Different doses of low-level laser irradiation modulate the in vitro response of osteoblast-like cells.

    PubMed

    Incerti Parenti, Serena; Checchi, Luigi; Fini, Milena; Tschon, Matilde

    2014-01-01

    Because osteoblasts play a key role in bone remodeling and the influence of low-level laser therapy on this process is not clear, Saos-2 human osteoblast-like cells were irradiated by a gallium-aluminum-arsenide diode laser (915 nm) for 10, 48, 96, 193, and 482 s using doses 1, 5, 10, 20, and 50 J/cm2, respectively. A control group was not irradiated. Morphology, viability, and cytotoxicity analyses were carried out after 1 hr, 1 day, and 3 days. Deoxyribose nucleic acid (DNA) content and release of vascular endothelial growth factor (VEGF), receptor activator of nuclear factor kappa B ligand (RANKL), and osteoprotegerin (OPG) were evaluated. Viability was modulated by laser irradiation in a dose-dependent manner, with 10 J/cm2 inducing a biostimulatory response and 20 to 50 J/cm2 determining a bioinhibitory and cytotoxic effect. Accordingly, DNA content was generally increased for the 10 J/cm2 dose and decreased for the 50 J/cm2 dose. A rapid and transitory trend toward increased RANKL/OPG ratio and a tendency toward a delayed increase in VEGF release for doses of 1 to 10 J/cm2 was found. Further investigations using the biostimulatory dose of 10 J/cm2 emerged from this study are needed to establish the ideal treatment regimens in the laboratory as well as in clinical practice. PMID:25279541

  7. Different doses of low-level laser irradiation modulate the in vitro response of osteoblast-like cells

    NASA Astrophysics Data System (ADS)

    Incerti Parenti, Serena; Checchi, Luigi; Fini, Milena; Tschon, Matilde

    2014-10-01

    Because osteoblasts play a key role in bone remodeling and the influence of low-level laser therapy on this process is not clear, Saos-2 human osteoblast-like cells were irradiated by a gallium-aluminum-arsenide diode laser (915 nm) for 10, 48, 96, 193, and 482 s using doses 1, 5, 10, 20, and 50 J/cm2, respectively. A control group was not irradiated. Morphology, viability, and cytotoxicity analyses were carried out after 1 hr, 1 day, and 3 days. Deoxyribose nucleic acid (DNA) content and release of vascular endothelial growth factor (VEGF), receptor activator of nuclear factor kappa B ligand (RANKL), and osteoprotegerin (OPG) were evaluated. Viability was modulated by laser irradiation in a dose-dependent manner, with 10 J/cm2 inducing a biostimulatory response and 20 to 50 J/cm2 determining a bioinhibitory and cytotoxic effect. Accordingly, DNA content was generally increased for the 10 J/cm2 dose and decreased for the 50 J/cm2 dose. A rapid and transitory trend toward increased RANKL/OPG ratio and a tendency toward a delayed increase in VEGF release for doses of 1 to 10 J/cm2 was found. Further investigations using the biostimulatory dose of 10 J/cm2 emerged from this study are needed to establish the ideal treatment regimens in the laboratory as well as in clinical practice.

  8. Determination of key radionuclides and parameters related to dose from the Columbia River pathway. Hanford Environmental Dose Reconstruction Project

    SciTech Connect

    Napier, B.A.

    1993-03-01

    A series of scoping calculations has been undertaken to evaluate the absolute and relative contributions of different radionuclides and exposure pathways to doses that may have been received by individuals living in the vicinity of the Hanford Site. These scoping calculations may include some radionuclides and pathways that were included in the Phase 1 Columbia River pathway dose evaluations, as well as other potential exposure pathways being evaluated for possible inclusion in future Hanford Environmental Dose Reconstruction Project (HEDR) modeling efforts. This scoping calculation (Calculation 009) examines the contributions of numerous radionuclides to dose via environmental exposures and accumulation in water, fish, and other aquatic biota. Addressed in these calculations are the contributions to effective dose from (1) external exposure to contaminated river water, ( 2) ingestion of contaminated drinking water, and (3) ingestion of contaminated resident Columbia River fish. Additional information on contamination of anadromous fish and waterfowl is provided.

  9. Consolidation Radiotherapy in Primary Central Nervous System Lymphomas: Impact on Outcome of Different Fields and Doses in Patients in Complete Remission After Upfront Chemotherapy

    SciTech Connect

    Ferreri, Andres Jose Maria; Verona, Chiara; Politi, Letterio Salvatore; Chiara, Anna; Perna, Lucia; Villa, Eugenio; Reni, Michele

    2011-05-01

    Purpose: Avoidance radiotherapy or reduction of irradiation doses in patients with primary central nervous system lymphoma (PCNSL) in complete remission (CR) after high-dose methotrexate (HD-MTX)-based chemotherapy has been proposed to minimize the neurotoxicity risk. Nevertheless, no study has focused on the survival impact of radiation parameters, as far as we know, and the optimal radiation schedule remains to be defined. Methods and Materials: The impact on outcome and neurologic performance of different radiation fields and doses was assessed in 33 patients with PCNSL who achieved CR after MTX-containing chemotherapy and were referred to consolidation whole-brain irradiation (WBRT). Patterns of relapse were analyzed on computed tomography-guided treatment planning, and neurologic impairment was assessed by the Mini Mental Status Examination. Results: At a median follow-up of 50 months, 21 patients are relapse-free (5-year failure-free survival [FFS], 51%). WBRT doses {>=}40 Gy were not associated with improved disease control in comparison with a WBRT dose of 30 to 36 Gy (relapse rate, 46% vs. 30%; 5-year FFS, 51% vs. 50%; p = 0.26). Disease control was not significantly different between patients irradiated to the tumor bed with 45 to 54 Gy or with 36 to 44 Gy, with a 5-year FFS of 35% and 44% (p = 0.43), respectively. Twenty patients are alive (5-year overall survival, 54%); WB and tumor bed doses did not have an impact on survival. Impairment as assessed by the Mini Mental Status Examination was significantly more common in patients treated with a WBRT dose {>=}40 Gy. Conclusion: Consolidation with WBRT 36 Gy is advisable in patients with PCNSL in CR after HD-MTX-based chemotherapy. Higher doses do not change the outcome and could increase the risk of neurotoxicity.

  10. A double-blind randomized clinical trial of different doses of transdermal nicotine patch for smoking reduction and cessation in long-term hospitalized schizophrenic patients.

    PubMed

    Chen, Hsing-Kang; Lan, Tsuo-Hung; Wu, Bo-Jian

    2013-02-01

    There have been many studies of smoking cessation using nicotine replacement therapy (NRT) with schizophrenic patients, but none exploring the smoking-reduction effects of varying doses of NRT in long-stay patients with schizophrenia. This study aimed to examine the effect of different doses of the nicotine transdermal patch on smoking-reduction and cessation outcomes in long-term hospitalized schizophrenic patients. A total of 184 subjects participated in a randomized, controlled, double-blind 8-week clinical trial. Participants were randomized into two groups using two different doses of NRT: a high-dose NRT group (31.2 mg for the first 4 weeks, then 20.8 mg for 4 weeks, n = 92) or a low-dose NRT group (20.8 mg for 8 weeks, n = 92). The 7-day point prevalence of abstinence was 2.7 % (5/184). Participants in the low-dose NRT group reduced smoking by 3.1 more cigarettes on average than those in the high-dose group (p = 0.005). However, a repeated measures analysis of variance revealed that the main effect of changes in the number of cigarettes smoked, comparing the two types of treatment across periods, was not significant (p = 0.35, partial eta square = 0.018). In summary, among a cohort of chronic institutionalized schizophrenic patients, smoking cessation and reduction outcomes were not correlated with NRT dose, and the cessation rate was much lower than rates in similar studies. It indicates that long-term hospitalized schizophrenic patients have more difficulties with quitting smoking. More effective integrative smoking cessation programs should be addressed for these patients.

  11. Neural Sensitivity to Absolute and Relative Anticipated Reward in Adolescents

    PubMed Central

    Vaidya, Jatin G.; Knutson, Brian; O'Leary, Daniel S.; Block, Robert I.; Magnotta, Vincent

    2013-01-01

    Adolescence is associated with a dramatic increase in risky and impulsive behaviors that have been attributed to developmental differences in neural processing of rewards. In the present study, we sought to identify age differences in anticipation of absolute and relative rewards. To do so, we modified a commonly used monetary incentive delay (MID) task in order to examine brain activity to relative anticipated reward value (neural sensitivity to the value of a reward as a function of other available rewards). This design also made it possible to examine developmental differences in brain activation to absolute anticipated reward magnitude (the degree to which neural activity increases with increasing reward magnitude). While undergoing fMRI, 18 adolescents and 18 adult participants were presented with cues associated with different reward magnitudes. After the cue, participants responded to a target to win money on that trial. Presentation of cues was blocked such that two reward cues associated with $.20, $1.00, or $5.00 were in play on a given block. Thus, the relative value of the $1.00 reward varied depending on whether it was paired with a smaller or larger reward. Reflecting age differences in neural responses to relative anticipated reward (i.e., reference dependent processing), adults, but not adolescents, demonstrated greater activity to a $1 reward when it was the larger of the two available rewards. Adults also demonstrated a more linear increase in ventral striatal activity as a function of increasing absolute reward magnitude compared to adolescents. Additionally, reduced ventral striatal sensitivity to absolute anticipated reward (i.e., the difference in activity to medium versus small rewards) correlated with higher levels of trait Impulsivity. Thus, ventral striatal activity in anticipation of absolute and relative rewards develops with age. Absolute reward processing is also linked to individual differences in Impulsivity. PMID:23544046

  12. Neural sensitivity to absolute and relative anticipated reward in adolescents.

    PubMed

    Vaidya, Jatin G; Knutson, Brian; O'Leary, Daniel S; Block, Robert I; Magnotta, Vincent

    2013-01-01

    Adolescence is associated with a dramatic increase in risky and impulsive behaviors that have been attributed to developmental differences in neural processing of rewards. In the present study, we sought to identify age differences in anticipation of absolute and relative rewards. To do so, we modified a commonly used monetary incentive delay (MID) task in order to examine brain activity to relative anticipated reward value (neural sensitivity to the value of a reward as a function of other available rewards). This design also made it possible to examine developmental differences in brain activation to absolute anticipated reward magnitude (the degree to which neural activity increases with increasing reward magnitude). While undergoing fMRI, 18 adolescents and 18 adult participants were presented with cues associated with different reward magnitudes. After the cue, participants responded to a target to win money on that trial. Presentation of cues was blocked such that two reward cues associated with $.20, $1.00, or $5.00 were in play on a given block. Thus, the relative value of the $1.00 reward varied depending on whether it was paired with a smaller or larger reward. Reflecting age differences in neural responses to relative anticipated reward (i.e., reference dependent processing), adults, but not adolescents, demonstrated greater activity to a $1 reward when it was the larger of the two available rewards. Adults also demonstrated a more linear increase in ventral striatal activity as a function of increasing absolute reward magnitude compared to adolescents. Additionally, reduced ventral striatal sensitivity to absolute anticipated reward (i.e., the difference in activity to medium versus small rewards) correlated with higher levels of trait Impulsivity. Thus, ventral striatal activity in anticipation of absolute and relative rewards develops with age. Absolute reward processing is also linked to individual differences in Impulsivity. PMID:23544046

  13. Comparison of two different doses of lidocaine on the pain sensation during transrectal ultrasound-guided prostate biopsy

    PubMed Central

    Ateş, Ferhat; Dursun, Furkan; Malkoç, Ercan; Yılmaz, Ömer; Soydan, Hasan; Şen, Hüseyin; Başal, Şeref; Zekey, Fatih; Karademir, Kenan

    2016-01-01

    Objective To compare two different doses of lidocaine used for periprostatic nerve block on pain perception during transrectal ultrasound (TRUS) guided prostate biopsy. Material and methods A total of 288 patients with elevated prostate specific antigen (PSA) levels and/or abnormal digital rectal examination who underwent TRUS-guided prostate biopsy were included in the study. The patients were divided into 3 groups: Group 1 (n=103) prostate biopsy were performed after administering perianal intrarectal application of 10 mL 2% lidocaine gel, Group 2 (n=98) 2 mL of 2% lidocaine injection on each side following rectal installation of lidocaine gel and Group 3 (n=87) 4 mL of 2% lidocaine injection on each side after rectal instillation of lidocaine gel. Patients’ pain scores during biopsy procedure were reported using visual analogue score (VAS). Independent sample t test, ANOVA test and Tukey test were used for statistical evaluation. Results The mean age, prostate volume and PSA level were 65.6±8.4 years, 58.2±34.8 mL, and 11.8±3.4 ng/mL respectively. There were no statistically significant differences in baseline characteristics between the groups. The mean VAS scores were 2.4±1.8 in Group 1, 2.5±1.9 in Group 2 and 1.6±1.6 in Group 3. Patients in Group 3, reported significant pain reduction compared with patients in Groups 1 and 2 (p=0.002, and 0.001, respectively). However, there was no statistically significant difference in VAS scores between Groups 1 and 2 (p=0.815). Conclusion According to our results we recommend the use of perianal intrarectal lidocain gel application, and periprostatic nerve block with injection of 4 ml 2% lidocaine per side combination in TRUS-guided prostate biopsies. Further large-scale randomized control studies are needed to validate these finding.

  14. Comparison of two different doses of lidocaine on the pain sensation during transrectal ultrasound-guided prostate biopsy

    PubMed Central

    Ateş, Ferhat; Dursun, Furkan; Malkoç, Ercan; Yılmaz, Ömer; Soydan, Hasan; Şen, Hüseyin; Başal, Şeref; Zekey, Fatih; Karademir, Kenan

    2016-01-01

    Objective To compare two different doses of lidocaine used for periprostatic nerve block on pain perception during transrectal ultrasound (TRUS) guided prostate biopsy. Material and methods A total of 288 patients with elevated prostate specific antigen (PSA) levels and/or abnormal digital rectal examination who underwent TRUS-guided prostate biopsy were included in the study. The patients were divided into 3 groups: Group 1 (n=103) prostate biopsy were performed after administering perianal intrarectal application of 10 mL 2% lidocaine gel, Group 2 (n=98) 2 mL of 2% lidocaine injection on each side following rectal installation of lidocaine gel and Group 3 (n=87) 4 mL of 2% lidocaine injection on each side after rectal instillation of lidocaine gel. Patients’ pain scores during biopsy procedure were reported using visual analogue score (VAS). Independent sample t test, ANOVA test and Tukey test were used for statistical evaluation. Results The mean age, prostate volume and PSA level were 65.6±8.4 years, 58.2±34.8 mL, and 11.8±3.4 ng/mL respectively. There were no statistically significant differences in baseline characteristics between the groups. The mean VAS scores were 2.4±1.8 in Group 1, 2.5±1.9 in Group 2 and 1.6±1.6 in Group 3. Patients in Group 3, reported significant pain reduction compared with patients in Groups 1 and 2 (p=0.002, and 0.001, respectively). However, there was no statistically significant difference in VAS scores between Groups 1 and 2 (p=0.815). Conclusion According to our results we recommend the use of perianal intrarectal lidocain gel application, and periprostatic nerve block with injection of 4 ml 2% lidocaine per side combination in TRUS-guided prostate biopsies. Further large-scale randomized control studies are needed to validate these finding. PMID:27635288

  15. Tolerance doses for treatment planning

    SciTech Connect

    Lyman, J.T.

    1985-10-01

    Data for the tolerance of normal tissues or organs to (low-LET) radiation has been compiled from a number of sources which are referenced at the end of this document. This tolerance dose data are ostensibly for uniform irradiation of all or part of an organ, and are for either 5% (TD/sub 5/) or 50% (TD/sub 50/) complication probability. The ''size'' of the irradiated organ is variously stated in terms of the absolute volume or the fraction of the organ volume irradiated, or the area or the length of the treatment field. The accuracy of these data is questionable. Much of the data represents doses that one or several experienced therapists have estimated could be safely given rather than quantitative analyses of clinical observations. Because these data have been obtained from multiple sources with possible different criteria for the definition of a complication, there are sometimes different values for what is apparently the same endpoint. The data from some sources shows a tendancy to be quantized in 5 Gy increments. This reflects the size of possible round off errors. It is believed that all these data have been accumulated without the benefit of 3-D dose distributions and therefore the estimates of the size of the volume and/or the uniformity of the irradiation may be less accurate than is now possible. 19 refs., 4 figs.

  16. Prospective randomized study of two different doses of clindamycin admixed with gentamicin in the management of perforated appendicitis.

    PubMed

    Yellin, A E; Berne, T V; Heseltine, P N; Appleman, M D; Gill, M; Chin, A; Baker, F J

    1993-04-01

    Septic complications after surgery for enterogenous peritonitis are minimized by adjuvant antibiotics effective against aerobes and anaerobes. Historically, "gold standard" therapy included an aminoglycoside plus clindamycin, the latter given at 600 mg intravenous piggyback (IVPB), every 6 hours. Clindamycin pharmacokinetics suggests that it can be given q8h and admixed with gentamicin, thereby markedly reducing the cost of administration. Although this is now common practice, there is no prospective study comparing the efficacy of the two dose schedules in peritonitis. This study was designed to test the hypothesis regarding the clinical efficacy of the two regimens. One hundred twenty-six patients with gangrenous (n = 34) or perforated appendicitis (n = 91) were randomized (2:1) to receive gentamicin admixed with clindamycin 900 mg IVPB every 8 hours (Group I n = 80) or gentamicin IVPB q8h plus clindamycin 600 mg IVPB every 6 hours (Group II n = 46). Appendectomy was performed, and aerobic and anaerobic cultures were obtained. Twenty-one patients had simultaneous determinations of clindamycin levels in plasma, peritoneal fluid, and appendix. Outcome analysis revealed no significant differences in postoperative days of fever, days non per os, antibiotic therapy, or hospitalization. There were 6 failures (4 abscesses and 2 wound infections) in Group I and 4 failures (1 abscess and 3 wound infections) in Group II. Both antibiotic regimens provided clinically equivalent results in mixed infections due to aerobic and anaerobic bacteria. The admixed clindamycin, administered every 8 hours, results in at least 20% reduction in costs. This is an important consideration.

  17. Absolute configuration of isovouacapenol C

    PubMed Central

    Fun, Hoong-Kun; Yodsaoue, Orapun; Karalai, Chatchanok; Chantrapromma, Suchada

    2010-01-01

    The title compound, C27H34O5 {systematic name: (4aR,5R,6R,6aS,7R,11aS,11bR)-4a,6-dihy­droxy-4,4,7,11b-tetra­methyl-1,2,3,4,4a,5,6,6a,7,11,11a,11b-dodeca­hydro­phenanthro[3,2-b]furan-5-yl benzoate}, is a cassane furan­oditerpene, which was isolated from the roots of Caesalpinia pulcherrima. The three cyclo­hexane rings are trans fused: two of these are in chair conformations with the third in a twisted half-chair conformation, whereas the furan ring is almost planar (r.m.s. deviation = 0.003 Å). An intra­molecular C—H⋯O inter­action generates an S(6) ring. The absolute configurations of the stereogenic centres at positions 4a, 5, 6, 6a, 7, 11a and 11b are R, R, R, S, R, S and R, respectively. In the crystal, mol­ecules are linked into infinite chains along [010] by O—H⋯O hydrogen bonds. C⋯O [3.306 (2)–3.347 (2) Å] short contacts and C—H⋯π inter­actions also occur. PMID:21588364

  18. Frequency-domain analysis of absolute gravimeters

    NASA Astrophysics Data System (ADS)

    Svitlov, S.

    2012-12-01

    An absolute gravimeter is analysed as a linear time-invariant system in the frequency domain. Frequency responses of absolute gravimeters are derived analytically based on the propagation of the complex exponential signal through their linear measurement functions. Depending on the model of motion and the number of time-distance coordinates, an absolute gravimeter is considered as a second-order (three-level scheme) or third-order (multiple-level scheme) low-pass filter. It is shown that the behaviour of an atom absolute gravimeter in the frequency domain corresponds to that of the three-level corner-cube absolute gravimeter. Theoretical results are applied for evaluation of random and systematic measurement errors and optimization of an experiment. The developed theory agrees with known results of an absolute gravimeter analysis in the time and frequency domains and can be used for measurement uncertainty analyses, building of vibration-isolation systems and synthesis of digital filtering algorithms.

  19. Study of absolute fast neutron dosimetry using CR-39 track detectors

    NASA Astrophysics Data System (ADS)

    El-Sersy, A. R.

    2010-06-01

    In this work, CR-39 track detectors have extensively been used in the determination of fast neutron fluence-to-dose factor. The registration efficiency, ɛ, of CR-39 detectors for fast neutrons was calculated using different theoretical approaches according to each mode of neutron interaction with the constituent atoms (H, C and O) of the detector material. The induced proton-recoiled showed the most common interaction among the others. The dependence of ɛ on both neutron energy and etching time was also studied. In addition, the neutron dose was calculated as a function of neutron energy in the range from 0.5 to 14 MeV using the values of (d E/d X) for each recoil particle in CR-39 detector. Results showed that the values of ɛ were obviously affected by both neutron energy and etching time where the contribution in ɛ from proton recoil was the most. The contribution from carbon and oxygen recoils in dose calculation was pronounced due to their higher corresponding values of d E/d X in comparison to those from proton recoils. The present calculated fluence-to-dose factor was in agreement with that either from ICRP no. 74 or from TRS no. 285 of IAEA, which reflected the importance of using CR-39 in absolute fast neutron dosimetry.

  20. SU-E-J-109: Evaluation of Deformable Accumulated Parotid Doses Using Different Registration Algorithms in Adaptive Head and Neck Radiotherapy

    SciTech Connect

    Xu, S; Liu, B

    2015-06-15

    Purpose: Three deformable image registration (DIR) algorithms are utilized to perform deformable dose accumulation for head and neck tomotherapy treatment, and the differences of the accumulated doses are evaluated. Methods: Daily MVCT data for 10 patients with pathologically proven nasopharyngeal cancers were analyzed. The data were acquired using tomotherapy (TomoTherapy, Accuray) at the PLA General Hospital. The prescription dose to the primary target was 70Gy in 33 fractions.Three DIR methods (B-spline, Diffeomorphic Demons and MIMvista) were used to propagate parotid structures from planning CTs to the daily CTs and accumulate fractionated dose on the planning CTs. The mean accumulated doses of parotids were quantitatively compared and the uncertainties of the propagated parotid contours were evaluated using Dice similarity index (DSI). Results: The planned mean dose of the ipsilateral parotids (32.42±3.13Gy) was slightly higher than those of the contralateral parotids (31.38±3.19Gy)in 10 patients. The difference between the accumulated mean doses of the ipsilateral parotids in the B-spline, Demons and MIMvista deformation algorithms (36.40±5.78Gy, 34.08±6.72Gy and 33.72±2.63Gy ) were statistically significant (B-spline vs Demons, P<0.0001, B-spline vs MIMvista, p =0.002). And The difference between those of the contralateral parotids in the B-spline, Demons and MIMvista deformation algorithms (34.08±4.82Gy, 32.42±4.80Gy and 33.92±4.65Gy ) were also significant (B-spline vs Demons, p =0.009, B-spline vs MIMvista, p =0.074). For the DSI analysis, the scores of B-spline, Demons and MIMvista DIRs were 0.90, 0.89 and 0.76. Conclusion: Shrinkage of parotid volumes results in the dose increase to the parotid glands in adaptive head and neck radiotherapy. The accumulated doses of parotids show significant difference using the different DIR algorithms between kVCT and MVCT. Therefore, the volume-based criterion (i.e. DSI) as a quantitative evaluation of

  1. [Dyslipidemic patients with coronary cardiopathy. Effect of different doses of OMEGA-3 fatty acids on serum lipids and lipoproteins].

    PubMed

    Arteaga, A; Villanueva, C L; Skorin, C; Guasch, V; Solís de Ovando, F; Velasco, N; Acosta, A M; Leighton, F

    1993-06-01

    Twenty one male patients aged 35 to 70 years, with coronary artery disease and dislipidemia refractory to dietary treatment, were assigned to three parallel groups of 7 individuals each that received a supplemental dose of 2, 4 and 6 g/day of omega-3 fatty acids during 60 days. After a 30 days wash-out period and 60 of supplementation, subjects were weighed, a dietary survey was performed, serum levels of total cholesterol and triglycerides, the lipid content of serum lipoproteins and the content of EPA+DHA in plasma phospholipids were measured. A dose dependent increase in EPA+DHA content of phospholipids and no changes in weight or nutrient intake were observed during the supplementation period. With the 6 g dose, a significant reduction in total cholesterol, with a reduction in VLDL and increase in LDL cholesterol and a decline in VLDL triglycerides was observed. With the 4 g dose a reduction in total cholesterol at the expense of VLDL and HDL cholesterol and a reduction in VLDL triglycerides but no changes in total triglycerides was observed. No changes in serum lipids were observed with 2 g dose. In patients with type IIA hyperlipidemia, a significant positive correlation was observed between DHA+EPA content of plasma phospholipids and LDL cholesterol, this correlation was not observed in patients with IIB or IV phenotypes. It is concluded that omega-3 fatty acids are ineffective as the only treatment for dislipidemias refractory to diet.

  2. Absolute calibration of ultraviolet filter photometry

    NASA Technical Reports Server (NTRS)

    Bless, R. C.; Fairchild, T.; Code, A. D.

    1972-01-01

    The essential features of the calibration procedure can be divided into three parts. First, the shape of the bandpass of each photometer was determined by measuring the transmissions of the individual optical components and also by measuring the response of the photometer as a whole. Secondly, each photometer was placed in the essentially-collimated synchrotron radiation bundle maintained at a constant intensity level, and the output signal was determined from about 100 points on the objective. Finally, two or three points on the objective were illuminated by synchrotron radiation at several different intensity levels covering the dynamic range of the photometers. The output signals were placed on an absolute basis by the electron counting technique described earlier.

  3. Impact of oral bisphenol A at reference doses on intestinal barrier function and sex differences after perinatal exposure in rats

    PubMed Central

    Braniste, Viorica; Jouault, Aurore; Gaultier, Eric; Polizzi, Arnaud; Buisson-Brenac, Claire; Leveque, Mathilde; Martin, Pascal G.; Theodorou, Vassilia; Fioramonti, Jean; Houdeau, Eric

    2009-01-01

    Bisphenol A (BPA), a chemical estrogen widely used in the food-packaging industry and baby bottles, is recovered in human fluids (0.1–10 nM). Recent studies have reported that BPA is hormonally active at low doses, emphasizing the debate of a risk for human health. Estrogen receptors are expressed in the colon, and although the major route of BPA exposure is food, the effects on gut have received no attention. We first examined the endocrine disrupting potency of BPA on colonic paracellular permeability (CPP), experimental colitis, and visceral sensitivity in ovariectomized rats orally exposed to 5 mg/kg/d BPA (i.e., the no observed adverse effect level), 50 μg/kg/d BPA (i.e., tolerable daily intake), or lower doses. BPA dose-dependently decreased basal CPP, with a half-maximal inhibitory dose of 5.2 μg/kg/d, 10-fold below the tolerable daily intake. This correlated with an increase in epithelial tight junction sealing, also observed in Caco-2 cells exposed to 10 nM BPA. When ovariectomized rats were fed with BPA at the no observed adverse effect level, the severity of colitis was reduced, whereas the same dose increased pain sensitivity to colorectal stimuli. We then examined the impact of perinatal exposure to BPA on intestinal permeability and inflammatory response in the offspring. In female rats, but not in male rats, perinatal BPA evoked a decrease of CPP in adulthood, whereas the proinflammatory response of colonic mucosa was strengthened. This study first demonstrates that the xenoestrogen BPA at reference doses influences intestinal barrier function and gut nociception. Moreover, perinatal exposure promotes the development of severe inflammation in adult female offspring only. PMID:20018722

  4. Detection of changes in DNA methylation induced by different doses of ground-base ion radiation in rice(oryza sativa L.)

    NASA Astrophysics Data System (ADS)

    Zhao, Qian; Sun, Yeqing; Wang, Wei; Wen, Bin

    Spaceflight represents a very complex environmental condition with highly ionizing radiations (HZE). To further investigate the incentives of ion effects in space environment, we performed on-ground simulated HZE particle radiations to rice seeds with different cumulative doses (0Gy, 0.01Gy, 0.02Gy, 0.1Gy, 0.2Gy, 1Gy , 2Gy, 5Gy, 20Gy ). Using Methylation-Sensitive Amplification Polymorphism (MSAP) analysis technology, differential polymorphism sites of DNA methylation of seedlings were analysed and acquired. The results showed that changes of methylation and demethylation on CCGG sites had taken place after irradiated treatments in all doses. It was noted that there was a stimulating effect in low-dose radiation(≤1 Gy). The minimum proportion of DNA methylation polymorphism level was 3.15% in 0.1Gy, whereas the maximum proportion was 9.87% in 2Gy, interestingly the proportion reduced with radiation doses increased, suggesting the dosage effects of radiation. We further found that the CG site tended to have a higher proportion of cytosine methylation alterations than CNG site in six of the eight dose groups. The results also indicated that different dose treatment groups showed various frequencies of methylation variation patterns: The type of CG hypermethylation was higher than CG hypormethylation in four low-dose groups (<≤2 Gy) ,whereas the result presented the opposite trends in all high-dose groups(>≥1 Gy). In addition, the type of CNG hypormethylation was obviously higher than the CNG hypermethylation in seven dose groups. This result indicated that the methylation variation patterns caused by radiation had site preferences. To investigate the mechanisms of sequences underlying alterations in DNA methylation after ion irradiation, we isolated, cloned and sequenced a subset of bands which showed obvious mutational bias. BLAST analysis indicated that many sequences showed significant homology to known function genes, most of which were related to

  5. Determination of the contribution of livestock water ingestion to dose from the cow-milk pathway. Hanford Environmental Dose Reconstruction Project: Dose code recovery activities, Calculation 002

    SciTech Connect

    Ikenberry, T.A.

    1992-12-01

    As part of the Hanford Environmental Dose Reconstruction (HEDR) Project, a series of calculations has been undertaken to evaluate the absolute and relative contribution of different exposure pathways to thyroid doses that may have been received by individuals living in the vicinity of the Hanford Site. These evaluations include some pathways that were included in the Phase I air-pathway dose evaluations (HEDR staff 1991, page xx), as well as other potential exposure pathways being evaluated for possible inclusion in the future HEDR modeling efforts. This calculation (002) examined the possible doses that may have been received by individuals who drank milk from cows that drank from sources of water (stock tanks and farm ponds) exposed to iodine-131 in the atmosphere during 1945.

  6. Determination of radionuclides and pathways contributing to dose in 1945. Hanford Environmental Dose Reconstruction Project: Dose code recovery activities, Calculation 003

    SciTech Connect

    Napier, B.A.

    1992-12-01

    A series of scoping calculations has been undertaken to evaluate the absolute and relative contributions of different radionuclides and exposure pathways to doses that may have been received by individuals living in the vicinity of the Hanford Site. This scoping calculation (Calculation 003) examined the contributions of numerous radionuclides to dose via environmental exposures and accumulation in foods. This study builds on the work initiated in the first scoping study of iodine in cow`s milk (calculation 001). Addressed in this calculation were the contributions to organ and effective dose of infants and adults from (1) air submersion and groundshine external dose, (2) inhalation, (3) ingestion of soil by humans, (4) ingestion of leafy vegetables, (5) ingestion of other vegetables and fruits, (6) ingestion of meat, (7) ingestion of eggs, and (8) ingestion of cows` milk from Feeding Regime 1, as described in Calculation 001.

  7. Antimuscarinic-induced convulsions in fasted animals after food intake: evaluation of the effects of levetiracetam, topiramate and different doses of atropine.

    PubMed

    Büget, Bahar; Türkmen, Aslı Zengin; Allahverdiyev, Oruc; Enginar, Nurhan

    2016-01-01

    This study evaluated the effects of different doses of atropine and new antiepileptics, levetiracetam and topiramate, on the development of convulsions triggered by food intake in antimuscarinic-treated fasted animals. Mice deprived of food for 24 h and treated i.p. with atropine at a dose of 2.4 or 24 mg/kg developed convulsions after being allowed to eat ad libitum. No convulsions were observed in fasted animals treated with 0.24 mg/kg atropine. There was no difference in the incidence of convulsions between the two atropine treatments, but latency to convulsions was longer in 24 mg/kg atropine treated animals. The lowest dose of atropine, 0.24 mg/kg, caused stage 1 and stage 2 activity, but did not provide the convulsive endpoint (stage 3, 4, 5 activity). Administration of levetiracetam (50 or 200 mg/kg) or topiramate (50 or 100 mg/kg) to another group of 24-h fasted mice was ineffective in reducing the incidence of convulsions developed in the animals after 2.4 mg/kg atropine treatment and food intake. However, the higher dose of levetiracetam prolonged the onset of convulsions. Present results demonstrated the efficacy of low and high doses of atropine on the development of convulsions in fasted animals and provided additional evidence for the ineffectiveness of antiepileptic treatment in these seizures.

  8. Scoping calculation for components of the cow-milk dose pathway for evaluating the dose contribution from iodine-131. Hanford Environmental Dose Reconstruction Project: Dose code recovery activities

    SciTech Connect

    Ikenberry, T.A.; Napier, B.A.

    1992-12-01

    A series of scoping calculations have been undertaken to evaluate The absolute and relative contribution of different exposure pathways to doses that may have been received by individuals living in the vicinity of the Hanford site. This scoping calculation (Calculation 001) examined the contributions of the various exposure pathways associated with environmental transport and accumulation of iodine-131 in the pasture-cow-milk pathway. Addressed in this calculation were the contributions to thyroid dose of infants and adult from (1) the ingestion by dairy cattle of various feedstuffs (pasturage, silage, alfalfa hay, and grass hay) in four different feeding regimes; (2) ingestion of soil by dairy cattle; (3) ingestion of stared feed on which airborne iodine-131 had been deposited; and (4) inhalation of airborne iodine-131 by dairy cows.

  9. SU-E-J-203: Investigation of 1.5T Magnetic Field Dose Effects On Organs of Different Density

    SciTech Connect

    Lee, H; Rubinstein, A; Ibbott, G

    2015-06-15

    Purpose: For the combined 1.5T/6MV MRI-linac system, the perpendicular magnetic field to the radiation beam results in altered radiation dose distributions. This Monte Carlo study investigates the change in dose at interfaces for common organs neighboring soft tissue. Methods: MCNP6 was used to simulate the effects of a 1.5T magnetic field when irradiating tissues with a 6 MV beam. The geometries used in this study were not necessarily anatomically representative in size in order to directly compare quantitative dose effects for each tissue at the same depths. For this purpose, a 512 cm{sup 3} cubic material was positioned at the center of a 2744 cm{sup 3} cubic soft tissue material phantom. The following tissue materials and their densities were used in this study: lung (0.296 g/cm{sup 3}), fat (0.95), spinal cord (1.038), soft tissue (1.04), muscle (1.05), eye (1.076), trabecular bone (1.40), and cortical bone (1.85). Results: The addition of a 1.5T magnetic field caused dose changes of +46.5%, +2.4%, −0.9%, −0.8%, −1.5%, −6.5%, and −8.8% at the entrance interface between soft tissue and lung, fat, spinal cord, muscle, eye, trabecular bone, and cortical bone tissues respectively. Dose changes of −39.4%, −4.1%, −0.8%, −0.8%, +0.5%, +6.7%, and +10.9% were observed at the second interface between the same tissues respectively and soft tissue. On average, the build-up distance was reduced by 0.6 cm, and a dose increase of 62.7% was observed at the exit interface between soft tissue and air of the entire phantom. Conclusion: The greatest changes in dose were observed at interfaces containing lung and bone tissues. Due to the prevalence and proximity of bony anatomy to soft tissues throughout the human body, these results encourage further examination of these tissues with anatomically representative geometries using multiple beam configurations for safe treatment using the MRI-linac system.

  10. [Absolute bioavailability of a special sustained-release acetylsalicylic acid formulation].

    PubMed

    Lücker, P W; Swoboda, M; Wetzelsberger, N

    1989-03-01

    Absolute Bioavailability of a Special Acetylsalicylic Acid Sustained Release Formulation. The absolute bioavailability of an acetylsalicylic acid (ASA) sustained release formulation (Contrheuma retard), containing 300 mg ASA as initial dose and 350 mg in a retard formulation, was determined in comparison to a standard ASA solution for intravenous administration in a two-treatment, two-period cross-over trial with 6 healthy male volunteers by comparing the areas under the plasma-fluctuation-time curves of the primary metabolite. In addition, it was examined by comparison of the mean times after administration of both formulations, whether the test formulation meets the requirements of a sustained release formulation. The investigations led to the following results: The absolute bioavailability of the test formulation was 95%. The statistical comparison of the areas under the concentration-time courses allowed no decision (neither for equivalence nor difference). The maximal concentration of SA after intravenous administration of the standard formulation was reached after 0.4 h on an average and amounted to 62 micrograms/ml. After oral administration of the test formulation, a mean concentration maximum of 28 micrograms/ml was calculated, which had been reached after about 2 h. The differences are statistically significant. The mean time for SA was 6 h after the standard formulation, whereas after administration of the test compound, a mean of 11.5 h was calculated. 24 h following administration, the concentration of SA was 1.3 micrograms/ml after intravenous administration of the standard formulation and 5.5 micrograms/ml after administration of the test formulation. These differences, too, are statistically significant. From the comparison of the mean time for SA, a retard factor of 1.9 was calculated. PMID:2757664

  11. Sex Differences in Dose Escalation and Overdose Death during Chronic Opioid Therapy: A Population-Based Cohort Study

    PubMed Central

    Kaplovitch, Eric; Gomes, Tara; Camacho, Ximena; Dhalla, Irfan A.; Mamdani, Muhammad M.; Juurlink, David N.

    2015-01-01

    Background The use of opioids for noncancer pain is widespread, and more than 16,000 die of opioid-related causes in the United States annually. The patients at greatest risk of death are those receiving high doses of opioids. Whether sex influences the risk of dose escalation or opioid-related mortality is unknown. Methods and Findings We conducted a cohort study using healthcare records of 32,499 individuals aged 15 to 64 who commenced chronic opioid therapy for noncancer pain between April 1, 1997 and December 31, 2010 in Ontario, Canada. Patients were followed from their first opioid prescription until discontinuation of therapy, death from any cause or the end of the study period. Among patients receiving chronic opioid therapy, 589 (1.8%) escalated to high dose therapy and n = 59 (0.2%) died of opioid-related causes while on treatment. After multivariable adjustment, men were more likely than women to escalate to high-dose opioid therapy (adjusted hazard ratio 1.44; 95% confidence interval 1.21 to 1.70) and twice as likely to die of opioid-related causes (adjusted hazard ratio 2.04; 95% confidence interval 1.18 to 3.53). These associations were maintained in a secondary analysis of 285,520 individuals receiving any opioid regardless of the duration of therapy. Conclusions Men are at higher risk than women for escalation to high-dose opioid therapy and death from opioid-related causes. Both outcomes were more common than anticipated. PMID:26291716

  12. Role of shielding in modulating the effects of solar particle events: Monte Carlo calculation of absorbed dose and DNA complex lesions in different organs

    NASA Astrophysics Data System (ADS)

    Ballarini, F.; Biaggi, M.; De Biaggi, L.; Ferrari, A.; Ottolenghi, A.; Panzarasa, A.; Paretzke, H. G.; Pelliccioni, M.; Sala, P.; Scannicchio, D.; Zankl, M.

    2004-01-01

    Distributions of absorbed dose and DNA clustered damage yields in various organs and tissues following the October 1989 solar particle event (SPE) were calculated by coupling the FLUKA Monte Carlo transport code with two anthropomorphic phantoms (a mathematical model and a voxel model), with the main aim of quantifying the role of the shielding features in modulating organ doses. The phantoms, which were assumed to be in deep space, were inserted into a shielding box of variable thickness and material and were irradiated with the proton spectra of the October 1989 event. Average numbers of DNA lesions per cell in different organs were calculated by adopting a technique already tested in previous works, consisting of integrating into "condensed-history" Monte Carlo transport codes - such as FLUKA - yields of radiobiological damage, either calculated with "event-by-event" track structure simulations, or taken from experimental works available in the literature. More specifically, the yields of "Complex Lesions" (or "CL", defined and calculated as a clustered DNA damage in a previous work) per unit dose and DNA mass (CL Gy -1 Da -1) due to the various beam components, including those derived from nuclear interactions with the shielding and the human body, were integrated in FLUKA. This provided spatial distributions of CL/cell yields in different organs, as well as distributions of absorbed doses. The contributions of primary protons and secondary hadrons were calculated separately, and the simulations were repeated for values of Al shielding thickness ranging between 1 and 20 g/cm 2. Slight differences were found between the two phantom types. Skin and eye lenses were found to receive larger doses with respect to internal organs; however, shielding was more effective for skin and lenses. Secondary particles arising from nuclear interactions were found to have a minor role, although their relative contribution was found to be larger for the Complex Lesions than for

  13. Absorbed dose to water reference dosimetry using solid phantoms in the context of absorbed-dose protocols

    SciTech Connect

    Seuntjens, Jan; Olivares, Marina; Evans, Michael; Podgorsak, Ervin

    2005-09-15

    For reasons of phantom material reproducibility, the absorbed dose protocols of the American Association of Physicists in Medicine (AAPM) (TG-51) and the International Atomic Energy Agency (IAEA) (TRS-398) have made the use of liquid water as a phantom material for reference dosimetry mandatory. In this work we provide a formal framework for the measurement of absorbed dose to water using ionization chambers calibrated in terms of absorbed dose to water but irradiated in solid phantoms. Such a framework is useful when there is a desire to put dose measurements using solid phantoms on an absolute basis. Putting solid phantom measurements on an absolute basis has distinct advantages in verification measurements and quality assurance. We introduce a phantom dose conversion factor that converts a measurement made in a solid phantom and analyzed using an absorbed dose calibration protocol into absorbed dose to water under reference conditions. We provide techniques to measure and calculate the dose transfer from solid phantom to water. For an Exradin A12 ionization chamber, we measured and calculated the phantom dose conversion factor for six Solid Water{sup TM} phantoms and for a single Lucite phantom for photon energies between {sup 60}Co and 18 MV photons. For Solid Water{sup TM} of certified grade, the difference between measured and calculated factors varied between 0.0% and 0.7% with the average dose conversion factor being low by 0.4% compared with the calculation whereas for Lucite, the agreement was within 0.2% for the one phantom examined. The composition of commercial plastic phantoms and their homogeneity may not always be reproducible and consistent with assumed composition. By comparing measured and calculated phantom conversion factors, our work provides methods to verify the consistency of a given plastic for the purpose of clinical reference dosimetry.

  14. Reducing Dose Uncertainty for Spot-Scanning Proton Beam Therapy of Moving Tumors by Optimizing the Spot Delivery Sequence

    PubMed Central

    Li, Heng; Zhu, X. Ronald; Zhang, Xiaodong

    2016-01-01

    Purpose To develop and validate a novel delivery strategy for reducing the respiratory motion–induced dose uncertainty of spot-scanning proton therapy. Methods and Materials The spot delivery sequence was optimized to reduce dose uncertainty. The effectiveness of the delivery sequence optimization was evaluated using measurements and patient simulation. One hundred ninety-one 2-dimensional measurements using different delivery sequences of a single-layer uniform pattern were obtained with a detector array on a 1-dimensional moving platform. Intensity modulated proton therapy plans were generated for 10 lung cancer patients, and dose uncertainties for different delivery sequences were evaluated by simulation. Results Without delivery sequence optimization, the maximum absolute dose error can be up to 97.2% in a single measurement, whereas the optimized delivery sequence results in a maximum absolute dose error of ≤11.8%. In patient simulation, the optimized delivery sequence reduces the mean of fractional maximum absolute dose error compared with the regular delivery sequence by 3.3% to 10.6% (32.5-68.0% relative reduction) for different patients. Conclusions Optimizing the delivery sequence can reduce dose uncertainty due to respiratory motion in spot-scanning proton therapy, assuming the 4-dimensional CT is a true representation of the patients’ breathing patterns. PMID:26460997

  15. Absolute Income, Relative Income, and Happiness

    ERIC Educational Resources Information Center

    Ball, Richard; Chernova, Kateryna

    2008-01-01

    This paper uses data from the World Values Survey to investigate how an individual's self-reported happiness is related to (i) the level of her income in absolute terms, and (ii) the level of her income relative to other people in her country. The main findings are that (i) both absolute and relative income are positively and significantly…

  16. Investigating Absolute Value: A Real World Application

    ERIC Educational Resources Information Center

    Kidd, Margaret; Pagni, David

    2009-01-01

    Making connections between various representations is important in mathematics. In this article, the authors discuss the numeric, algebraic, and graphical representations of sums of absolute values of linear functions. The initial explanations are accessible to all students who have experience graphing and who understand that absolute value simply…

  17. Preschoolers' Success at Coding Absolute Size Values.

    ERIC Educational Resources Information Center

    Russell, James

    1980-01-01

    Forty-five 2-year-old and forty-five 3-year-old children coded relative and absolute sizes using 1.5-inch, 6-inch, and 18-inch cardboard squares. Results indicate that absolute coding is possible for children of this age. (Author/RH)

  18. Introducing the Mean Absolute Deviation "Effect" Size

    ERIC Educational Resources Information Center

    Gorard, Stephen

    2015-01-01

    This paper revisits the use of effect sizes in the analysis of experimental and similar results, and reminds readers of the relative advantages of the mean absolute deviation as a measure of variation, as opposed to the more complex standard deviation. The mean absolute deviation is easier to use and understand, and more tolerant of extreme…

  19. Monolithically integrated absolute frequency comb laser system

    DOEpatents

    Wanke, Michael C.

    2016-07-12

    Rather than down-convert optical frequencies, a QCL laser system directly generates a THz frequency comb in a compact monolithically integrated chip that can be locked to an absolute frequency without the need of a frequency-comb synthesizer. The monolithic, absolute frequency comb can provide a THz frequency reference and tool for high-resolution broad band spectroscopy.

  20. Estimating the absolute wealth of households

    PubMed Central

    Gerkey, Drew; Hadley, Craig

    2015-01-01

    Abstract Objective To estimate the absolute wealth of households using data from demographic and health surveys. Methods We developed a new metric, the absolute wealth estimate, based on the rank of each surveyed household according to its material assets and the assumed shape of the distribution of wealth among surveyed households. Using data from 156 demographic and health surveys in 66 countries, we calculated absolute wealth estimates for households. We validated the method by comparing the proportion of households defined as poor using our estimates with published World Bank poverty headcounts. We also compared the accuracy of absolute versus relative wealth estimates for the prediction of anthropometric measures. Findings The median absolute wealth estimates of 1 403 186 households were 2056 international dollars per capita (interquartile range: 723–6103). The proportion of poor households based on absolute wealth estimates were strongly correlated with World Bank estimates of populations living on less than 2.00 United States dollars per capita per day (R2 = 0.84). Absolute wealth estimates were better predictors of anthropometric measures than relative wealth indexes. Conclusion Absolute wealth estimates provide new opportunities for comparative research to assess the effects of economic resources on health and human capital, as well as the long-term health consequences of economic change and inequality. PMID:26170506

  1. Absolute optical metrology : nanometers to kilometers

    NASA Technical Reports Server (NTRS)

    Dubovitsky, Serge; Lay, O. P.; Peters, R. D.; Liebe, C. C.

    2005-01-01

    We provide and overview of the developments in the field of high-accuracy absolute optical metrology with emphasis on space-based applications. Specific work on the Modulation Sideband Technology for Absolute Ranging (MSTAR) sensor is described along with novel applications of the sensor.

  2. SU-E-T-371: Validation of Organ Doses Delivered During Craniospinal Irradiation with Helical Tomotherapy

    SciTech Connect

    Perez-Andujar, A; Chen, J; Garcia, A; Haas-Kogan, D

    2014-06-01

    Purpose: New techniques have been developed to deliver more conformal treatments to the craniospinal axis. One concern, however, is the widespread low dose delivered and implications for possible late effects. The purpose of this work is for the first time to validate the organ doses calculated by the treatment planning system (TPS), including out-of-field doses for a pediatric craniospinal treatment (CSI). Methods: A CSI plan prescribed to 23.4 Gy and a posterior fossa boost plan to 30.6 Gy (total dose 54.0 Gy) was developed for a pediatric anthropomorphic phantom representing a 13 yearold- child. For the CSI plan, the planning target volumes (PTV) consisted of the brain and spinal cord with 2 mm and 5 mm expansions, respectively. Organs at risk (OAR) were contoured and included in the plan optimization. The plans were delivered on a helical tomotherapy unit. Thermoluminescent dosimeters (TLDs) were used to measure the dose at 54 positions within the PTV and OARs. Results: For the CSI treatment, the mean percent difference between TPS dose calculations and measurements was 5% for the PTV and 10% for the OARs. For the boost, the average was 3% for the PTV. The percent difference for the OARs, which lie outside the field and received a small fraction of the prescription dose, varied from 15% to 200%. However in terms of absolute dose, the average difference between measurement and TPS per treatment Gy was 2 cGy/Gy and 3 mGy/Gy for the CSI and boost plans, respectively. Conclusion: There was good agreement between doses calculated by the TPS and measurements for the CSI treatment. Higher percent differences were observed for out-of-field doses in the boost plan, but absolute dose differences were very small compared to the prescription dose. These findings can help in the estimation of late effects after radiotherapy for pediatric patients.

  3. Effect of differing doses of inhaled budesonide on markers of airway inflammation in patients with mild asthma

    PubMed Central

    Jatakanon, A.; Kharitonov, S.; Lim, S.; Barnes, P.

    1999-01-01

    BACKGROUND—It is desirable to prescribe the minimal effective dose of inhaled steroids to control asthma. To ensure that inflammation is suppressed whilst using the lowest possible dose, a sensitive and specific method for assessing airway inflammation is needed.
METHODS—The usefulness of exhaled nitric oxide (NO), sputum eosinophils, and methacholine airway responsiveness (PC20) for monitoring airway inflammatory changes following four weeks of treatment with an inhaled corticosteroid (budesonide via Turbohaler) were compared. Mild stable steroid naive asthmatic subjects were randomised into two double blind, placebo controlled studies. The first was a parallel group study involving three groups receiving either 100 µg/day budesonide (n = 8), 400 µg/day budesonide (n = 7), or a matched placebo (n = 6). The second was a crossover study involving 10 subjects randomised to receive 1600 µg budesonide or placebo. The groups were matched with respect to age, PC20, baseline FEV1 (% predicted), exhaled NO, and sputum eosinophilia.
RESULTS—There were significant improvements in FEV1 following 400 µg and 1600 µg budesonide (11.3% and 6.5%, respectively, p<0.05). This was accompanied by significant reductions in eosinophil numbers in induced sputum (0.7 and 0.9 fold, p<0.05). However, levels of exhaled NO were reduced following each budesonide dose while PC20 was improved only with 1600 µg budesonide. These results suggest that exhaled NO and PC20 may not reflect the control of airway inflammation as accurately as the number of eosinophils in sputum. There were dose dependent changes in exhaled NO, sputum eosinophils, and PC20 to inhaled budesonide but a plateau response of exhaled NO was found at a dose of 400 µg daily.
CONCLUSION—Monitoring the number of eosinophils in induced sputum may be the most accurate guide to establish the minimum dose of inhaled steroids needed to control inflammation. This, however, requires further studies involving a larger

  4. Absolute instability of the Gaussian wake profile

    NASA Technical Reports Server (NTRS)

    Hultgren, Lennart S.; Aggarwal, Arun K.

    1987-01-01

    Linear parallel-flow stability theory has been used to investigate the effect of viscosity on the local absolute instability of a family of wake profiles with a Gaussian velocity distribution. The type of local instability, i.e., convective or absolute, is determined by the location of a branch-point singularity with zero group velocity of the complex dispersion relation for the instability waves. The effects of viscosity were found to be weak for values of the wake Reynolds number, based on the center-line velocity defect and the wake half-width, larger than about 400. Absolute instability occurs only for sufficiently large values of the center-line wake defect. The critical value of this parameter increases with decreasing wake Reynolds number, thereby indicating a shrinking region of absolute instability with decreasing wake Reynolds number. If backflow is not allowed, absolute instability does not occur for wake Reynolds numbers smaller than about 38.

  5. Absolute neutrophil values in malignant patients on cytotoxic chemotherapy.

    PubMed

    Madu, A J; Ibegbulam, O G; Ocheni, S; Madu, K A; Aguwa, E N

    2011-01-01

    A total of eighty patients with various malignancies seen between September 2008 and April 2009 at the University of Nigeria Teaching Hospital (UNTH) Ituku Ozalla, Enugu, Nigeria, had their absolute neutrophil counts, done at Days 0 and 12 of the first cycle of their various chemotherapeutic regimens. They were adult patients who had been diagnosed of various malignancies, consisting of Breast cancer 36 (45%), Non-Hodgkin's lymphoma 8 (10%), Hodgkin's lymphoma 13 (16.25%), Colorectal carcinoma 6 (7.5%), Multiple myeloma 7 (8.75%), Cervical carcinoma 1 (1.25%) and other malignancies 9 (11.25%), Manual counting of absolute neutrophil count was done using Turks solution and improved Neubauer counting chamber and Galen 2000 Olympus microscope. The socio demographic data of the patients were assessed from a questionnaire. There were 27 males (33.75%) and 53 females (66.25%). Their ages ranged from 18 - 80 years with a median of 45 years. The mean absolute neutrophil count of the respondents pre-and post chemotherapy was 3.7 +/- 2.1 x 10(9)/L and 2.5 +/- 1.6 x 10(9)/L respectively. There were significant differences in both the absolute neutrophil count (p=0.00) compared to the pre-chemotherapy values. Chemotherapeutic combinations containing cyclophosphamide and Adriamycin were observed to cause significant reduction in absolute neutrophil.

  6. A clinical trial of malaria prophylaxis using a single dose of chloroquine at different intervals in an endemic malarious area.

    PubMed

    Karunakaran, C S

    1980-10-01

    A controlled trial of chloroquine prophylaxis was carried out to find whether this drug could be administered at intervals longer than the conventional ones recommended, in endemic malarious areas. Statistically significant results obtained show that chloroquine at suitable doses could be used successfully at intervals of 3 months. The possibility of chloroquine and acquired immunity acting together synergistically is discussed. The author is of the opinion that with this dose regime, the community would still be able to build up substantial immunity, so that in the event of the drug being discontinued, the community would not be faced with the problem of overwhelming malarial infections. The various advantages in using this regime are also considered.

  7. [Hypoglycemic action of different doses of nopal (Opuntia streptacantha Lemaire) in patients with type II diabetes mellitus].

    PubMed

    Frati-Munari, A C; Del Valle-Martínez, L M; Ariza-Andraca, C R; Islas-Andrade, S; Chávez-Negrete, A

    1989-01-01

    To assess the relationship between the doses of O. streptacantha Lem. and its acute hypoglycemic action in diabetics, eight patients with type II diabetes mellitus were studied. Four test were performed to each patient with the intake of: (a) 400 ml of water, (b) 100 g (c) 300 g and (d) 500 g of broiled stems of O. streptacantha Lem. Serum glucose was measured at 0, 60, 120 and 180 minutes. Maximal decrease of serum glucose was noticed at 180 minutes, with a mean of 2.3, 10, 30.1 and 46.7 mg/dl less than basal value with 0, 100, 300 and 500 g respectively (P = NS, less than 0.05, less than 0.001 and less than 0.001 respectively). A significant direct correlation (r = 0.690, P less than 0.001) was noticed between the doses and the hypoglycemic effect. PMID:2557805

  8. The Protective Effect of Low-Dose Aspirin against Colorectal Cancer Is Unlikely Explained by Selection Bias: Results from Three Different Study Designs in Clinical Practice

    PubMed Central

    Cea Soriano, Lucía; Soriano-Gabarró, Montse; García Rodríguez, Luis A.

    2016-01-01

    Background We conducted three differently designed nested case–control studies to evaluate whether the protective effect of low-dose aspirin against colorectal cancer (CRC) is explained by selection bias. Methods Using a large validated UK primary care database, we followed different cohorts of patients, who varied in their demographic and clinical characteristics, to identify first ever cases of CRC. In Studies 1 and 2, two cohorts were followed, i) new users of low-dose aspirin at start of follow-up (N = 170,336 in Study 1, N = 171,527 in Study 2) and either ii) non-users of low-dose aspirin (Study 1, N = 170,336) or new users of paracetamol (Study 2, N = 149,597) at start of follow-up. In Study 3 a single cohort of individuals näive to low-dose aspirin at the start of observation was followed. Controls were selected using incidence sampling and logistic regression used to obtain an unbiased estimate of the incidence rate ratio (RR) with 95% confidence intervals (CIs). Low-dose aspirin exposure was analyzed ‘as-treated’ before the index date (CRC date for cases, random date for controls). Results In the three studies, median (maximum) follow-up was 5.1 (12), 5.8 (12) and 7.5 (13) years, respectively. 3033 incident CRC cases were identified in Study 1, 3174 in Study 2, and 12,333 in Study 3. Current use of low-dose aspirin was associated with a significantly reduced risk of 34%, 29% and 31% in the three studies, respectively; corresponding RRs (95% CIs) were 0.66 (0.60–0.73), 0.71 (0.63–0.80) and 0.69 (0.64–0.74). In each study, significantly reduced risks of CRC were seen when low-dose aspirin was used for primary or secondary cardiovascular disease prevention, in both sexes, and across all age groups evaluated. Conclusion Low-dose aspirin is associated with a significantly reduced risk of CRC. The consistency of our findings across different studies makes selection bias an unlikely explanation. PMID:27428004

  9. Blast cell methotrexate-polyglutamate accumulation in vivo differs by lineage, ploidy, and methotrexate dose in acute lymphoblastic leukemia.

    PubMed Central

    Synold, T W; Relling, M V; Boyett, J M; Rivera, G K; Sandlund, J T; Mahmoud, H; Crist, W M; Pui, C H; Evans, W E

    1994-01-01

    High-dose methotrexate (HDMTX) is a component of most treatment protocols for childhood acute lymphoblastic leukemia (ALL), yet recent studies of receptor-mediated transport and saturable polyglutamylation have questioned its rationale. To investigate this in vivo, methotrexate and its active polyglutamated metabolites (MTX-PG) were measured in bone marrow blasts obtained from 101 children randomized to single-agent therapy with either HDMTX (1 g/m2 per 24 h i.v., n = 47) or low-dose MTX (LDMTX, 30 mg/m2 by mouth every 6 h x 6, n = 54), before remission induction therapy. Blast concentrations of total MTX-PGs (median 460 vs 1380 pmol/10(9) cells) and of long-chain MTX-glu4-6 were both significantly higher after HDMTX (P < 0.001). With either treatment, MTX-PGs were significantly higher in B-lineage blasts than in T-lineage blasts (LDMTX P = 0.001, HDMTX P = 0.03). In a multiple regression analysis of B-lineage ALL, blast MTX-PG was significantly related to MTX dose (or plasma MTX concentration), lymphoblast ploidy (hyperdiploid > nonhyperdiploid), and percentage S-phase. This is the first evidence that HDMTX achieves higher MTX-PG concentrations in ALL blasts in vivo, establishing a rationale for HDMTX in the treatment of childhood ALL, especially T-lineage or nonhyperdiploid B-lineage ALL, disease characteristics associated with a poor prognosis on conventional therapy. Images PMID:7525652

  10. Analysis of standard reference materials by absolute INAA

    SciTech Connect

    Heft, R.E.; Koszykowski, R.F.

    1981-07-01

    Three standard reference materials, flyash, soil, and ASI 4340 steel, were analyzed by a method of absolute instrumental neutron activation analysis (INAA). Two different light water pool-type reactors were used to produce equivalent analytical results even though the epithermal to thermal flux ratio in one reactor was higher than that in the other by a factor of two.

  11. Multifrequency continuous wave terahertz spectroscopy for absolute thickness determination

    SciTech Connect

    Scheller, Maik; Baaske, Kai; Koch, Martin

    2010-04-12

    We present a tunable multifrequency continuous wave terahertz spectrometer based on two laser diodes, photoconductive antennas, and a coherent detection scheme. The system is employed to determine the absolute thickness of samples utilizing a proposed synthetic difference frequency method to circumvent the 2pi uncertainty known from conventional photomixing systems while preserving a high spatial resolution.

  12. Pharmacogenetic-Based Efavirenz Dose Modification: Suggestions for an African Population and the Different CYP2B6 Genotypes

    PubMed Central

    Mukonzo, Jackson K.; Owen, Joel S.; Ogwal-Okeng, Jasper; Kuteesa, Ronald B.; Nanzigu, Sarah; Sewankambo, Nelson; Thabane, Lehana; Gustafsson, Lars L.; Ross, Colin; Aklillu, Eleni

    2014-01-01

    Background Pharmacogenetics contributes to inter-individual variability in pharmacokinetics (PK) of efavirenz (EFV), leading to variations in both efficacy and toxicity. The purpose of this study was to assess the effect of genetic factors on EFV pharmacokinetics, treatment outcomes and genotype based EFV dose recommendations for adult HIV-1 infected Ugandans. Methods In total, 556 steady-state plasma EFV concentrations from 99 HIV infected patients (64 female) treated with EFV/lamivudine/zidovidine were analyzed. Patient genotypes for CYP2B6 (*6 & *11), CYP3A5 (*3,*6 & *7) and ABCB1 c.4046A>G, baseline biochemistries and CD4 and viral load change from baseline were determined. A one-compartment population PK model with first-order absorption (NONMEM) was used to estimate genotype effects on EFV pharmacokinetics. PK simulations were performed based upon population genotype frequencies. Predicted AUCs were compared between the product label and simulations for doses of 300 mg, 450 mg, and 600 mg. Results EFV apparent clearance (CL/F) was 2.2 and 1.74 fold higher in CYP2B6*6 (*1/*1) and CYP2B6*6 (*1/*6) compared CYP2B6*6 (*6/*6) carriers, while a 22% increase in F1 was observed for carriers of ABCB1 c.4046A>G variant allele. Higher mean AUC was attained in CYP2B6 *6/*6 genotypes compared to CYP2B6 *1/*1 (p<0.0001). Simulation based AUCs for 600 mg doses were 1.25 and 2.10 times the product label mean AUC for the Ugandan population in general and CYP2B6*6/*6 genotypes respectively. Simulated exposures for EFV daily doses of 300 mg and 450 mg are comparable to the product label. Viral load fell precipitously on treatment, with only six patients having HIV RNA >40 copies/mL after 84 days of treatment. No trend with exposure was noted for these six patients. Conclusion Results of this study suggest that daily doses of 450 mg and 300 mg might meet the EFV treatment needs of HIV-1 infected Ugandans in general and individuals homozygous for CYP2B6*6 mutation, respectively

  13. Determination of radionuclides and pathways contributing to dose in 1945

    SciTech Connect

    Napier, B.A.

    1992-12-01

    A series of scoping calculations has been undertaken to evaluate the absolute and relative contributions of different radionuclides and exposure pathways to doses that may have been received by individuals living in the vicinity of the Hanford Site. This scoping calculation (Calculation 003) examined the contributions of numerous radionuclides to dose via environmental exposures and accumulation in foods. This study builds on the work initiated in the first scoping study of iodine in cow's milk (calculation 001). Addressed in this calculation were the contributions to organ and effective dose of infants and adults from (1) air submersion and groundshine external dose, (2) inhalation, (3) ingestion of soil by humans, (4) ingestion of leafy vegetables, (5) ingestion of other vegetables and fruits, (6) ingestion of meat, (7) ingestion of eggs, and (8) ingestion of cows' milk from Feeding Regime 1, as described in Calculation 001.

  14. Estimation of dose to man from environmental tritium

    SciTech Connect

    Rohwer, P S; Etnier, E L

    1980-01-01

    Factors important for characterization of tritium in environmental pathways leading to exposure of man are reviewed and quantification of those factors is discussed. Parameters characterizing the behavior of tritium in man are also subjected to review. Factors to be discussed include organic binding, bioaccumulation, quality factor and transmutation. A variety of models are presently in use to estimate dose to man from environmental releases of tritium. Results from four representative models are compared and discussed. Site-specific information is always preferable when parameterizing models to estimate dose to man. There may be significant differences in dose potential among geographic regions due to variable factors. An example of one such factor examined is absolute humidity. It is concluded that adequate methodologies exist for estimation of dose to man from environmental tritium although a number of areas are identified where additional tritium research is desirable.

  15. The Impact of Different Levels of Adaptive Iterative Dose Reduction 3D on Image Quality of 320-Row Coronary CT Angiography: A Clinical Trial

    PubMed Central

    Feger, Sarah; Rief, Matthias; Zimmermann, Elke; Martus, Peter; Schuijf, Joanne Désirée; Blobel, Jörg; Richter, Felicitas; Dewey, Marc

    2015-01-01

    Purpose The aim of this study was the systematic image quality evaluation of coronary CT angiography (CTA), reconstructed with the 3 different levels of adaptive iterative dose reduction (AIDR 3D) and compared to filtered back projection (FBP) with quantum denoising software (QDS). Methods Standard-dose CTA raw data of 30 patients with mean radiation dose of 3.2 ± 2.6 mSv were reconstructed using AIDR 3D mild, standard, strong and compared to FBP/QDS. Objective image quality comparison (signal, noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), contour sharpness) was performed using 21 measurement points per patient, including measurements in each coronary artery from proximal to distal. Results Objective image quality parameters improved with increasing levels of AIDR 3D. Noise was lowest in AIDR 3D strong (p≤0.001 at 20/21 measurement points; compared with FBP/QDS). Signal and contour sharpness analysis showed no significant difference between the reconstruction algorithms for most measurement points. Best coronary SNR and CNR were achieved with AIDR 3D strong. No loss of SNR or CNR in distal segments was seen with AIDR 3D as compared to FBP. Conclusions On standard-dose coronary CTA images, AIDR 3D strong showed higher objective image quality than FBP/QDS without reducing contour sharpness. Trial Registration Clinicaltrials.gov NCT00967876 PMID:25945924

  16. A study protocol for quantitative targeted absolute proteomics (QTAP) by LC-MS/MS: application for inter-strain differences in protein expression levels of transporters, receptors, claudin-5, and marker proteins at the blood–brain barrier in ddY, FVB, and C57BL/6J mice

    PubMed Central

    2013-01-01

    Proteomics has opened a new horizon in biological sciences. Global proteomic analysis is a promising technology for the discovery of thousands of proteins, post-translational modifications, polymorphisms, and molecular interactions in a variety of biological systems. The activities and roles of the identified proteins must also be elucidated, but this is complicated by the inability of conventional proteomic methods to yield quantitative information for protein expression. Thus, a variety of biological systems remain “black boxes”. Quantitative targeted absolute proteomics (QTAP) enables the determination of absolute expression levels (mol) of any target protein, including low-abundance functional proteins, such as transporters and receptors. Therefore, QTAP will be useful for understanding the activities and roles of individual proteins and their differences, including normal/disease, human/animal, or in vitro/in vivo. Here, we describe the study protocols and precautions for QTAP experiments including in silico target peptide selection, determination of peptide concentration by amino acid analysis, setup of selected/multiple reaction monitoring (SRM/MRM) analysis in liquid chromatography–tandem mass spectrometry, preparation of protein samples (brain capillaries and plasma membrane fractions) followed by the preparation of peptide samples, simultaneous absolute quantification of target proteins by SRM/MRM analysis, data analysis, and troubleshooting. An application of QTAP in biological sciences was introduced that utilizes data from inter-strain differences in the protein expression levels of transporters, receptors, tight junction proteins and marker proteins at the blood–brain barrier in ddY, FVB, and C57BL/6J mice. Among 18 molecules, 13 (abcb1a/mdr1a/P-gp, abcc4/mrp4, abcg2/bcrp, slc2a1/glut1, slc7a5/lat1, slc16a1/mct1, slc22a8/oat3, insr, lrp1, tfr1, claudin-5, Na+/K+-ATPase, and γ-gtp) were detected in the isolated brain capillaries, and their

  17. Behaviors of the percentage depth dose curves along the beam axis of a phantom filled with different clinical PTO objects, a Monte Carlo Geant4 study

    NASA Astrophysics Data System (ADS)

    EL Bakkali, Jaafar; EL Bardouni, Tarek; Safavi, Seyedmostafa; Mohammed, Maged; Saeed, Mroan

    2016-08-01

    The aim of this work is to assess the capabilities of Monte Carlo Geant4 code to reproduce the real percentage depth dose (PDD) curves generated in phantoms which mimic three important clinical treatment situations that include lung slab, bone slab, bone-lung slab geometries. It is hoped that this work will lead us to a better understanding of dose distributions in an inhomogeneous medium, and to identify any limitations of dose calculation algorithm implemented in the Geant4 code. For this purpose, the PDD dosimetric functions associated to the three clinical situations described above, were compared to one produced in a homogeneous water phantom. Our results show, firstly, that the Geant4 simulation shows potential mistakes on the shape of the calculated PDD curve of the first physical test object (PTO), and it is obviously not able to successfully predict dose values in regions near to the boundaries between two different materials. This is, surely due to the electron transport algorithm and it is well-known as the artifacts at interface phenomenon. To deal with this issue, we have added and optimized the StepMax parameter to the dose calculation program; consequently the artifacts due to the electron transport were quasi disappeared. However, the Geant4 simulation becomes painfully slow when we attempt to completely resolve the electron artifact problems by considering a smaller value of an electron StepMax parameter. After electron transport optimization, our results demonstrate the medium-level capabilities of the Geant4 code to modeling dose distribution in clinical PTO objects.

  18. Differences in Clinical Results After LINAC-Based Single-Dose Radiosurgery Versus Fractionated Stereotactic Radiotherapy for Patients With Vestibular Schwannomas

    SciTech Connect

    Combs, Stephanie E.; Welzel, Thomas; Schulz-Ertner, Daniela; Huber, Peter E.; Debus, Juergen

    2010-01-15

    Purpose: To evaluate the outcomes of patients with vestibular schwannoma (VS) treated with fractionated stereotactic radiotherapy (FSRT) vs. those treated with stereotactic radiosurgery (SRS). Methods and Materials: This study is based on an analysis of 200 patients with 202 VSs treated with FSRT (n = 172) or SRS (n = 30). Patients with tumor progression and/or progression of clinical symptoms were selected for treatment. In 165 out of 202 VSs (82%), RT was performed as the primary treatment for VS, and for 37 VSs (18%), RT was conducted for tumor progression after neurosurgical intervention. For patients receiving FSRT, a median total dose of 57.6 Gy was prescribed, with a median fractionation of 5 x 1.8 Gy per week. For patients who underwent SRS, a median single dose of 13 Gy was prescribed to the 80% isodose. Results: FSRT and SRS were well tolerated. Median follow-up time was 75 months. Local control was not statistically different for both groups. The probability of maintaining the pretreatment hearing level after SRS with doses of <=13 Gy was comparable to that of FSRT. The radiation dose for the SRS group (<=13 Gy vs. >13 Gy) significantly influenced hearing preservation rates (p = 0.03). In the group of patients treated with SRS doses of <=13 Gy, cranial nerve toxicity was comparable to that of the FSRT group. Conclusions: FSRT and SRS are both safe and effective alternatives for the treatment of VS. Local control rates are comparable in both groups. SRS with doses of <=13 Gy is a safe alternative to FSRT. While FSRT can be applied safely for the treatment of VSs of all sizes, SRS should be reserved for smaller lesions.

  19. Evaluation of dose equivalent by the electronic personal dosemeter for neutron 'Saphydose-N' at different workplaces of nuclear facilities.

    PubMed

    Chau, Q; Lahaye, T

    2007-01-01

    This paper presents the results of measurements made with the electronic personal neutron Saphydose-N during the four campaigns of the European contract EVIDOS (EValuation of Individual DOSimetry in mixed neutron and photon radiation fields). These measurements were performed at Institute for Radiological Protection and Nuclear Safety (IRSN) in France (C0), at the Krümmel Nuclear Power Plant in Germany (C1), at the VENUS Research Reactor and the Belgonucléaire fuel processing plant in Belgium (C2) and at the Ringhals Nuclear Power Plant in Sweden (C3). The results for Saphydose-N are compared with reference values for dose equivalent.

  20. Differences in 3D dose distributions due to calculation method of voxel S-values and the influence of image blurring in SPECT

    NASA Astrophysics Data System (ADS)

    Pacilio, Massimiliano; Amato, Ernesto; Lanconelli, Nico; Basile, Chiara; Torres, Leonel Alberto; Botta, Francesca; Ferrari, Mahila; Cornejo Diaz, Nestor; Coca Perez, Marco; Fernández, María; Lassmann, Michael; Vergara Gil, Alex; Cremonesi, Marta

    2015-03-01

    This study compares 3D dose distributions obtained with voxel S values (VSVs) for soft tissue, calculated by several methods at their current state-of-the-art, varying the degree of image blurring. The methods were: 1) convolution of Dose Point Kernel (DPK) for water, using a scaling factor method; 2) an analytical model (AM), fitting the deposited energy as a function of the source-target distance; 3) a rescaling method (RSM) based on a set of high-resolution VSVs for each isotope; 4) local energy deposition (LED). VSVs calculated by direct Monte Carlo simulations were assumed as reference. Dose distributions were calculated considering spheroidal clusters with various sizes (251, 1237 and 4139 voxels of 3 mm size), uniformly filled with 131I, 177Lu, 188Re or 90Y. The activity distributions were blurred with Gaussian filters of various widths (6, 8 and 12 mm). Moreover, 3D-dosimetry was performed for 10 treatments with 90Y derivatives. Cumulative Dose Volume Histograms (cDVHs) were compared, studying the differences in D95%, D50% or Dmax (ΔD95%, ΔD50% and ΔDmax) and dose profiles. For unblurred spheroidal clusters, ΔD95%, ΔD50% and ΔDmax were mostly within some percents, slightly higher for 177Lu with DPK (8%) and RSM (12%) and considerably higher for LED (ΔD95% up to 59%). Increasing the blurring, differences decreased and also LED yielded very similar results, but D95% and D50% underestimations between 30-60% and 15-50%, respectively (with respect to 3D-dosimetry with unblurred distributions), were evidenced. Also for clinical images (affected by blurring as well), cDVHs differences for most methods were within few percents, except for slightly higher differences with LED, and almost systematic for dose profiles with DPK (-1.2%), AM (-3.0%) and RSM (4.5%), whereas showed an oscillating trend with LED. The major concern for 3D-dosimetry on clinical SPECT images is more strongly represented by image blurring than by differences among the VSVs

  1. Enhancement of Peroxidase Release from Non-Malignant and Malignant Cells through Low-Dose Irradiation with Different Radiation Quality.

    PubMed

    Abdelrazzak, Abdelrazek B; Pottgießer, Stefanie J; Hill, Mark A; O'Neill, Peter; Bauer, Georg

    2016-02-01

    The release of peroxidase by nontransformed or transformed fibroblasts or epithelial cells (effector cells) triggers apoptosis induction selectively in transformed fibroblasts or transformed epithelial cells (target cells) through intercellular apoptosis-inducing signaling. The release of peroxidase can be induced either by treatment with transforming growth factor beta 1 or by low doses of alpha particles, gamma rays or ultrasoft X rays. In addiation, data indicates that radiation quality does not determine the overall efficiency of peroxidase release and the effects among a wide range of radiation doses are indistinguishable. These findings suggested that peroxidase release might be being triggered through intercellular bystander signaling. We show here that maximal peroxidase release does indeed occur after coculture of a small number of irradiated cells with an excess of unirradiated cells and demonstrate an enhanced effector function of nontransformed cells after the addition of a small number of irradiated cells. These data strongly indicate that peroxidase release is indeed triggered through bystander signaling mechanisms in mammalian cells.

  2. Effects of different doses of gamma irradiation on oxygen and water vapour transmission rate of preserved human amniotic membrane.

    PubMed

    Zahari, Nor Kamalia; Sheikh Ab Hamid, Suzina; Yusof, Norimah

    2015-03-01

    Preserved human amniotic membrane either air dried or glycerol preserved has been used effectively to treat superficial and partial thickness wounds without leaving any obvious hypertrophic scar. The preserved amnion, sterilised by ionising radiation, is known as an effective barrier for heat, fluid and protein loss while adheres nicely on wound. Air drying slightly reduced the oxygen transmission rate (OTR) of the amnion and the value significantly dropped after 15 kGy (p < 0.05). Glycerol preservation significantly reduced (p < 0.05) the OTR indicating less oxygen transmitted through the well structured cells of the amnion. Increase in the OTR with the increasing radiation doses up to 35 kGy possibly due to direct effects of radiation that resulted in large intercellular gaps. Both preservation methods significantly increased (p < 0.05) the water vapour transmission rate (WVTR). However, the low WVTR in the air dried amnion at 15 and 25 kGy was postulated due to cross-linking of collagen. Changes in the biophysical properties can be linked to direct and indirect effects of radiation on collagen bundles. The radiation dose of 25 kGy caused no adverse effect on biophysical properties hence it is still acceptable to sterilize both the air dried and the glycerol preserved amnions.

  3. Filling, postcholecystokinin emptying, and refilling of normal gallbladder: effects of two different doses of CCK on refilling: concise communication

    SciTech Connect

    Mesgarzadeh, M.; Krishnamurthy, G.T.; Bobba, V.R.; Langrell, K.

    1983-08-01

    A study of 18 normal subjects was undertaken to evaluate the rapidity of gallbladder filling with Tc-99m IDA during fast, and the degree of emptying and incidence of refilling after intravenous infusion of either 20 or 40 ng/kg of octapeptide of cholecystokinin (CCK-8). During fast, the frequency of onset of gallbladder filling with Tc-99m IDA at 20, 30, 40, and 42 min was 68%, 84%, 95%, and 100%, respectively. Following CCK-8 infusion, the gallbladder mean ejection period of 11 +- 4 (s.d.) min and ejection fraction of 40% +- 23 were similar in subjects given either a 20 ng/kg or a 40 ng/kg dose. The frequency of onset of refilling at 20, 30, 40, and 50 min after CCK-8 was 33%, 63%, 71%, and 79%, respectively for the combined groups. There was no correlation between the degree of emptying (ejection fraction) and onset of refilling. We conclude that the frequency of post CCK-8 onset of gallbladder refilling, which reflects sphincter tone recovery, is widely variable, depending upon both the dose and the duration from the time of infusion of CCK-8 and should be taken into consideration if a preemptying procedure is adopted during hepatobiliary imaging with Tc-99m IDA agents.

  4. Filling, postcholecystokinin emptying, and refilling of normal gallbladder: effects of two different doses of CCK on refilling: concise communication

    SciTech Connect

    Mesgarzadeh, M.; Krishnamurthy, G.T.; Bobba, V.R.; Langrell, K.

    1983-08-01

    A study of 18 normal subjects was undertaken to evaluate the rapidity of gallbladder filling with Tc-99m IDA during fast, and the degree of emptying and incidence of refilling after intravenous infusion of either 20 or 40 ng/kg of octapeptide of cholecystokinin (CCK-8). During fast, the frequency of onset of gallbladder filling with Tc-99m IDA at 20, 30, 40, and 42 min was 68%, 84%, 95%, and 100%, respectively. Following CCK-8 infusion, the gallbladder mean ejection period of 11 +/- 4 (s.d.) min and ejection fraction of 40% +/- 23 were similar in subjects given either a 20 ng/kg or a 40 ng/kg dose. The frequency of onset of refilling at 20, 30, 40, and 50 min after CCK-8 was 33%, 63%, 71%, and 79%, respectively for the combined groups. At 50 min after CCK-8, all subjects given 20 ng/kg refilled, whereas only 63% of the 40-ng/kg group did so. There was no correlation between the degree of emptying (ejection fraction) and onset of refilling. We conclude that the frequency of post CCK-8 onset of gallbladder refilling, which reflects sphincter tone recovery, is widely variable, depending upon both the dose and the duration from the time of infusion of CCK-8 and should be taken into consideration if a pre-emptying procedure is adopted during hepatobiliary imaging with Tc-99m IDA agents.

  5. Enhancement of Peroxidase Release from Non-Malignant and Malignant Cells through Low-Dose Irradiation with Different Radiation Quality.

    PubMed

    Abdelrazzak, Abdelrazek B; Pottgießer, Stefanie J; Hill, Mark A; O'Neill, Peter; Bauer, Georg

    2016-02-01

    The release of peroxidase by nontransformed or transformed fibroblasts or epithelial cells (effector cells) triggers apoptosis induction selectively in transformed fibroblasts or transformed epithelial cells (target cells) through intercellular apoptosis-inducing signaling. The release of peroxidase can be induced either by treatment with transforming growth factor beta 1 or by low doses of alpha particles, gamma rays or ultrasoft X rays. In addiation, data indicates that radiation quality does not determine the overall efficiency of peroxidase release and the effects among a wide range of radiation doses are indistinguishable. These findings suggested that peroxidase release might be being triggered through intercellular bystander signaling. We show here that maximal peroxidase release does indeed occur after coculture of a small number of irradiated cells with an excess of unirradiated cells and demonstrate an enhanced effector function of nontransformed cells after the addition of a small number of irradiated cells. These data strongly indicate that peroxidase release is indeed triggered through bystander signaling mechanisms in mammalian cells. PMID:26849404

  6. Investigation into image quality and dose for different patient geometries with multiple cone-beam CT systems

    SciTech Connect

    Gardner, Stephen J.; Studenski, Matthew T.; Giaddui, Tawfik; Galvin, James; Yu, Yan; Xiao, Ying; Cui, Yunfeng

    2014-03-15

    Purpose: To provide quantitative and qualitative image quality metrics and imaging dose for modern Varian On-board Imager (OBI) (ver. 1.5) and Elekta X-ray Volume Imager (XVI) (ver. 4.5R) cone-beam computed tomography (CBCT) systems in a clinical adaptive radiation therapy environment by accounting for varying patient thickness. Methods: Image quality measurements were acquired with Catphan 504 phantom (nominal diameter and with additional 10 cm thickness) for OBI and XVI systems and compared to planning CT (pCT) (GE LightSpeed). Various clinical protocols were analyzed for the OBI and XVI systems and analyzed using image quality metrics, including spatial resolution, low contrast detectability, uniformity, and HU sensitivity. Imaging dose measurements were acquired in Wellhofer Scanditronix i'mRT phantom at nominal phantom diameter and with additional 4 cm phantom diameter using GafChromic XRQA2 film. Calibration curves were generated using previously published in-air Air Kerma calibration method. Results: The OBI system full trajectory scans exhibited very little dependence on phantom thickness for accurate HU calculation, while half-trajectory scans with full-fan filter exhibited dependence of HU calculation on phantom thickness. The contrast-to-noise ratio (CNR) for the OBI scans decreased with additional phantom thickness. The uniformity of Head protocol scan was most significantly affected with additional phantom thickness. The spatial resolution and CNR compared favorably with pCT, while the uniformity of the OBI system was slightly inferior to pCT. The OBI scan protocol dose levels for nominal phantom thickness at the central portion of the phantom were 2.61, 0.72, and 1.88 cGy, and for additional phantom thickness were 1.95, 0.48, and 1.52 cGy, for the Pelvis, Thorax, and Spotlight protocols, respectively. The XVI system scans exhibited dependence on phantom thickness for accurate HU calculation regardless of trajectory. The CNR for the XVI scans decreased

  7. [Correction of the combined vitamin deficiency in growing rats fed fiber enriched diets with different doses of vitamins].

    PubMed

    Beketova, N A; Kodentsova, V M; Vrzhesinskaia, O A; Kosheleva, O V; Pereverzeva, O G; Sokol'nikov, A A; Aksenov, I V

    2014-01-01

    The effect of 5% dietary wheat bran (WB) on the correction of combined vitamin deficiency by two doses of vitamins (physiological and enhanced) has been analyzed using a rat model (8 groups, n = 8/group). Vitamin deficiency in male weanling Wistar rats (58.1 ± 0.5 g) was induced by 5-fold reduction of vitamin mixture amount in the feed and complete vitamin E, B1 and B2 exclusion from the mixture for 30 days, then deficit was corrected within 5 days. Rats from control group were fed a complete semisynthetic diet containing microcrystalline cellulose 2%. Vitamin deficient diet for 35 days resulted in reduced (p < 0.05) levels of vitamin A in the liver by 25 fold, vitamin E and B1--2.0-2.3 fold, vitamin B2--by 40%, 25(OH)D blood plasma concentration--by 21% compared with the control. Feed consumption of the animals treated with vitamin deficient diet and WB was higher by 43% than in rats with vitamin deficit. Their rate of weight occupied the intermediate position between the rates of weight in deficit and in control animals, and they could not serve a full control to evaluate the WB impact on vitamin sufficiency. After filling the vitamin diet content to an adequate level vitamin E liver content was fully restored. To restore vitamins B1 and B2 liver level higher doses of vitamins (120-160% of adequate content) were required, and to restore the reduced levels of vitamin A in rat liver even 2-fold increased dose of vitamin A was insufficient. The diet enrichment with WB had no effect on vitamin B1 and B2 liver content, regardless of the amount of vitamins in the diet. Adding fiber to the diet of animals adequately provided with vitamins resulted in significantly 1,3-fold increase of 25(OH)D blood plasma concentration and a slight but significant decrease of α-tocopherol liver level by 16% as compared to rats not receiving WB. The enrichment of rat diet with dietary fibers worsened restoration of the reduced vitamin E status not only by filling vitamin content in the

  8. Angular on-line tube current modulation in multidetector CT examinations of children and adults: The influence of different scanning parameters on dose reduction

    SciTech Connect

    Papadakis, Antonios E.; Perisinakis, Kostas; Damilakis, John

    2007-07-15

    The purpose of this study was to assess the potential of angular on-line tube current modulation on dose reduction in pediatric and adult patients undergoing multidetector computed tomography (MDCT) examinations. Five physical anthropomorphic phantoms that simulate the average individual as neonate, 1-year-old, 5-year-old, 10-year-old, and adult were employed in the current study. Phantoms were scanned with the use of on-line tube current modulation (TCM). Percent dose reduction (%DR) factors achieved by applying TCM, were determined for standard protocols used for head and neck, shoulder, thorax, thorax and abdomen, abdomen, abdomen and pelvis, pelvis, and whole body examinations. A preliminary study on the application of TCM in MDCT examinations of adult patients was performed to validate the results obtained in anthropomorphic phantoms. Dose reduction was estimated as the percentage difference of the modulated milliamperes for each scan and the preset milliamperes prescribed by the scan protocol. The dose reduction in children was found to be much lower than the corresponding reduction achieved for adults. For helical scans the %DR factors, ranged between 1.6% and 7.4% for the neonate, 2.9% and 8.7% for the 1-year old, 2% and 6% for the 5-year-old, 5% and 10.9% for the 10-year-old, and 10.4% and 20.7% for the adult individual. For sequential scans the corresponding %DR factors ranged between 1.3% and 6.7%, 4.5% and 11%, 4.2% and 6.6%, 6.4% and 12.3%, and 8.9% and 23.3%, respectively. Broader beam collimations are associated with decreased %DR factors, when other scanning parameters are held constant. TCM did not impair image noise. In adult patients, the %DR values were found to be in good agreement with the corresponding results obtained in the anthropomorphic adult phantom. In conclusion, on-line TCM may be considered as a valuable tool for reducing dose in routine CT examinations of pediatric and adult patients. However, the dose reduction achieved with TCM

  9. Differences in HCV Viral Decline between Low and Standard-Dose Pegylated-Interferon-Alpha-2a with Ribavirin in HIV/HCV Genotype 3 Patients

    PubMed Central

    Rivero-Juárez, Antonio; Lopez-Cortes, Luis F.; Camacho, Angela; Torres-Cornejo, Almudena; Pineda, Juan A.; Marquez-Solero, Manuel; Caruz, Antonio; Ruiz-Valderas, Rosa; Torre-Cisneros, Julian; Gutierrez-Valencia, Alicia; Rivero, Antonio

    2012-01-01

    Background The aim of the study was to analyze the different impact of standard and low-dose Peg-IFN-α2a/RBV therapies on HCV viral decline in HIV/HCV genotype 3 co-infected patients during the first weeks of treatment. Methods Plasma HCV viral decline was analyzed between baseline and weeks 1, 2 and 4 in two groups of treatment-naïve HCV genotype 3 patients with HIV co-infection. The Standard Dose Group (SDG) included patients who received Peg-IFN at 180 µg/per week with a weight-adjusted dose of ribavirin; Low-Dose Group (LDG) patients received Peg-IFN at 135 µg/per week with 800 mg/day ribavirin. The effect of IL28B genotype on HCV viral decline was evaluated in both groups. HCV viral decline was analyzed using a multivariate linear regression model. Results One hundred and six patients were included: 48 patients in the SDG and 58 in the LDG. HCV viral decline for patients in the LDG was less than for those in the SDG (week 1∶1.72±0.74 log10 IU/mL versus 1.78±0.67 log10 IU/mL, p = 0.827; week 2∶2.3±0.89 log10 IU/mL versus 3.01±1.02 log10 IU/mL, p = 0.013; week 4∶3.52±1.2 log10 IU/mL versus 4.09±1.1 log10 IU/mL, p = 0.005). The linear regression model identified the Peg-IFN/RBV dose as an independent factor for HCV viral decline at week 4. Conclusions Our results showed that HCV viral decline was less for patients in the low-dose group compared to those receiving the standard dose. Until a randomized clinical trial is conducted, clinicians should be cautious about using lower doses of Peg-IFN/RBV in HIV/HCV genotype 3 co-infected patients. PMID:23145040

  10. Mobilization and collection of CD34+ cells for autologous transplantation of peripheral blood hematopoietic progenitor cells in children: analysis of two different granulocyte-colony stimulating factor doses

    PubMed Central

    Eid, Kátia Aparecida de Brito; Miranda, Eliana Cristina Martins; Aguiar, Simone dos Santos

    2015-01-01

    Introduction The use of peripheral hematopoietic progenitor cells (HPCs) is the cell choice in autologous transplantation. The classic dose of granulocyte-colony stimulating factor (G-CSF) for mobilization is a single daily dose of 10 μg/kg of patient body weight. There is a theory that higher doses of granulocyte-colony stimulating factor applied twice daily could increase the number of CD34+ cells collected in fewer leukapheresis procedures. Objective The aim of this study was to compare a fractionated dose of 15 μg G-CSF/kg of body weight and the conventional dose of granulocyte-colony stimulating factor in respect to the number of leukapheresis procedures required to achieve a minimum collection of 3 × 106 CD34+ cells/kg body weight. Methods Patients were divided into two groups: Group 10 – patients who received a single daily dose of 10 μg G-CSF/kg body weight and Group 15 – patients who received a fractioned dose of 15 μg G-CSF/kg body weight daily. The leukapheresis procedure was carried out in an automated cell separator. The autologous transplantation was carried out when a minimum number of 3 × 106 CD34+ cells/kg body weight was achieved. Results Group 10 comprised 39 patients and Group 15 comprised 26 patients. A total of 146 apheresis procedures were performed: 110 (75.3%) for Group 10 and 36 (24.7%) for Group 15. For Group 10, a median of three (range: 1–7) leukapheresis procedures and a mean of 8.89 × 106 CD34+ cells/kg body weight (±9.59) were collected whereas for Group 15 the corresponding values were one (range: 1–3) and 5.29 × 106 cells/kg body weight (±4.95). A statistically significant difference was found in relation to the number of apheresis procedures (p-value <0.0001). Conclusions To collect a minimum target of 3 × 106 CD34+ cells/kg body weight, the administration of a fractionated dose of 15 μg G-CSF/kg body weight significantly decreased the number of leukapheresis procedures performed. PMID:26041417

  11. Dissolution profiles of perindopril and indapamide in their fixed-dose formulations by a new HPLC method and different mathematical approaches.

    PubMed

    Gumieniczek, Anna; Mączka, Paulina; Komsta, Łukasz; Pietraś, Rafał

    2015-09-01

    A new HPLC method was introduced and validated for simultaneous determination of perindopril and indapamide. Validation procedure included specificity, sensitivity, robustness, stability, linearity, precision and accuracy. The method was used for the dissolution test of perindopril and indapamide in three fixed-dose formulations. The dissolution procedure was optimized using different media, different pH of the buffer, surfactants, paddle speed and temperature. Similarity of dissolution profiles was estimated using different model-independent and model-dependent methods and, additionally, by principal component analysis (PCA). Also, some kinetic models were checked for dissolved amounts of drugs as a function of time. PMID:26431103

  12. Absolute magnitudes of trans-neptunian objects

    NASA Astrophysics Data System (ADS)

    Duffard, R.; Alvarez-candal, A.; Pinilla-Alonso, N.; Ortiz, J. L.; Morales, N.; Santos-Sanz, P.; Thirouin, A.

    2015-10-01

    Accurate measurements of diameters of trans- Neptunian objects are extremely complicated to obtain. Radiomatric techniques applied to thermal measurements can provide good results, but precise absolute magnitudes are needed to constrain diameters and albedos. Our objective is to measure accurate absolute magnitudes for a sample of trans- Neptunian objects, many of which have been observed, and modelled, by the "TNOs are cool" team, one of Herschel Space Observatory key projects grantes with ~ 400 hours of observing time. We observed 56 objects in filters V and R, if possible. These data, along with data available in the literature, was used to obtain phase curves and to measure absolute magnitudes by assuming a linear trend of the phase curves and considering magnitude variability due to rotational light-curve. In total we obtained 234 new magnitudes for the 56 objects, 6 of them with no reported previous measurements. Including the data from the literature we report a total of 109 absolute magnitudes.

  13. A New Gimmick for Assigning Absolute Configuration.

    ERIC Educational Resources Information Center

    Ayorinde, F. O.

    1983-01-01

    A five-step procedure is provided to help students in making the assignment absolute configuration less bothersome. Examples for both single (2-butanol) and multi-chiral carbon (3-chloro-2-butanol) molecules are included. (JN)

  14. The Simplicity Argument and Absolute Morality

    ERIC Educational Resources Information Center

    Mijuskovic, Ben

    1975-01-01

    In this paper the author has maintained that there is a similarity of thought to be found in the writings of Cudworth, Emerson, and Husserl in his investigation of an absolute system of morality. (Author/RK)

  15. Mathematical Model for Absolute Magnetic Measuring Systems in Industrial Applications

    NASA Astrophysics Data System (ADS)

    Fügenschuh, Armin; Fügenschuh, Marzena; Ludszuweit, Marina; Mojsic, Aleksandar; Sokół, Joanna

    2015-09-01

    Scales for measuring systems are either based on incremental or absolute measuring methods. Incremental scales need to initialize a measurement cycle at a reference point. From there, the position is computed by counting increments of a periodic graduation. Absolute methods do not need reference points, since the position can be read directly from the scale. The positions on the complete scales are encoded using two incremental tracks with different graduation. We present a new method for absolute measuring using only one track for position encoding up to micrometre range. Instead of the common perpendicular magnetic areas, we use a pattern of trapezoidal magnetic areas, to store more complex information. For positioning, we use the magnetic field where every position is characterized by a set of values measured by a hall sensor array. We implement a method for reconstruction of absolute positions from the set of unique measured values. We compare two patterns with respect to uniqueness, accuracy, stability and robustness of positioning. We discuss how stability and robustness are influenced by different errors during the measurement in real applications and how those errors can be compensated.

  16. Analysis of dose-incidence relationships for marrow failure in different species, in terms of radiosensitivity of tissue-rescuing units

    SciTech Connect

    Hendry, J.H.; Roberts, S.A. )

    1990-05-01

    The analysis of 68 published sets of dose-incidence data for marrow failure in different species, using a double-log mortality function, indicates: (a) There is more heterogeneity, i.e. greater sums-of-squares per degree of freedom, within the data sets for mouse than for larger species (monkey, dog, sheep, goat, pig). (b) For mice the curves for acute doses are characterized by a D0 of about 100 cGy for tissue-rescuing units (or target cells), which are depleted at most to about 3 x 10(-4) at LD50. (c) Larger species are much less tolerant to target-cell depletion, the corresponding level being consistently in the range of 10(-2)-10(-3) at LD50. Also, the D0 is often lower (approximately 55 cGy), which is compatible in the dog with such a value for hemopoietic progenitor cells. (d) With larger species there is an unexpected reduction in heterogeneity when the dose rate is lower, which gives a D0 lower than expected and a higher extrapolate. It is concluded that the position and slope of the dose-incidence curves are compatible with interpretations based primarily on target-cell number and survival characteristics, modified by additional heterogeneity factors.

  17. Evaluation of different doses of mashua (Tropaeolum tuberosum) on the reduction of sperm production, motility and morphology in adult male rats.

    PubMed

    Leiva-Revilla, J; Cárdenas-Valencia, I; Rubio, J; Guerra-Castañón, F; Olcese-Mori, P; Gasco, M; Gonzales, G F

    2012-05-01

    Mashua is an edible-tuber crop that grows in the Andean region. Folk medicine describes the use of mashua to reduce reproductive function in men. The present study aimed: (i) to determine whether different doses of mashua (0.01, 0.1, 1 and 2 g kg(-1)) produced a dose-response reduction on sperm production and quality; and, (ii) to determine whether these anti-reproductive effects of mashua can be reversible after cessation of treatment (12 and 24 days of recovery time). Mashua-treated rats showed lower values of daily sperm production, epididymal and vas deferens sperm count and sperm motility; meanwhile, mashua increased the percentage of abnormal sperm morphology and epididymal sperm transit rate. The following variables follow a dose-response effect: sperm number in vas deferens, sperm motility and sperm transit rate. In addition, it was demonstrated that the reduction in reproduction function in male rats treated with mashua was reversible after 24 days of recovery time. Finally, lower doses mashua reduces sperm number and quality (motility and morphology), and these adverse effects on male reproductive system may be reversible after 24 days after cessation of the treatment.

  18. Comparison of Accuracy in Calculation of Absorbed Dose to Patients Following Bone Scan with 99mTc-Marked Diphosphonates by Two Different Background Correction Methods

    PubMed Central

    Shahbazi-Gahrouei, Daryoush; Damoori, Mehri; Tavakoli, Mohammad Bagher; Moslehi, Masoud

    2016-01-01

    To improve the accuracy of the activity quantification and the image quality in scintigraphy, scatter correction is a vital procedure. The aim of this study is to compare the accuracy in calculation of absorbed dose to patients following bone scan with 99mTc-marked diphosphonates (99mTc-MDP) by two different methods of background correction in conjugate view method. This study involved 22 patients referring to the Nuclear Medicine Center of Shahid Chamran Hospital, Isfahan, Iran. After the injection of 99mTc-MDP, whole-body images from patients were acquired at 10, 60, 90, and 180 min. Organ activities were calculated using the conjugate view method by Buijs and conventional background correction. Finally, the absorbed dose was calculated using the Medical Internal Radiation Dosimetry (MIRD) technique. The results of this study showed that the absorbed dose per unit of injected activity (rad/mCi) ± standard deviation for pelvis bone, bladder, and kidneys by Buijs method was 0.19 ± 0.05, 0.08 ± 0.01, and 0.03 ± 0.01 and by conventional method was 0.13 ± 0.04, 0.08 ± 0.01, and 0.024 ± 0.01, respectively. This showed that Buijs background correction method had a high accuracy compared to conventional method for the estimated absorbed dose of bone and kidneys whereas, for the bladder, its accuracy was low. PMID:27014610

  19. Analysis of small field percent depth dose and profiles: Comparison of measurements with various detectors and effects of detector orientation with different jaw settings

    PubMed Central

    Godson, Henry Finlay; Ravikumar, M.; Sathiyan, S.; Ganesh, K. M.; Ponmalar, Y. Retna; Varatharaj, C.

    2016-01-01

    The advent of modern technologies in radiotherapy poses an increased challenge in the determination of dosimetric parameters of small fields that exhibit a high degree of uncertainty. Percent depth dose and beam profiles were acquired using different detectors in two different orientations. The parameters such as relative surface dose (DS), depth of dose maximum (Dmax), percentage dose at 10 cm (D10), penumbral width, flatness, and symmetry were evaluated with different detectors. The dosimetric data were acquired for fields defined by jaws alone, multileaf collimator (MLC) alone, and by MLC while the jaws were positioned at 0, 0.25, 0.5, and 1.0 cm away from MLC leaf-end using a Varian linear accelerator with 6 MV photon beam. The accuracy in the measurement of dosimetric parameters with various detectors for three different field definitions was evaluated. The relative DS(38.1%) with photon field diode in parallel orientation was higher than electron field diode (EFD) (27.9%) values for 1 cm ×1 cm field. An overestimation of 5.7% and 8.6% in D10 depth were observed for 1 cm ×1 cm field with RK ion chamber in parallel and perpendicular orientation, respectively, for the fields defined by MLC while jaw positioned at the edge of the field when compared to EFD values in parallel orientation. For this field definition, the in-plane penumbral widths obtained with ion chamber in parallel and perpendicular orientation were 3.9 mm, 5.6 mm for 1 cm ×1 cm field, respectively. Among all detectors used in the study, the unshielded diodes were found to be an appropriate choice of detector for the measurement of beam parameters in small fields. PMID:27051165

  20. Analysis of small field percent depth dose and profiles: Comparison of measurements with various detectors and effects of detector orientation with different jaw settings.

    PubMed

    Godson, Henry Finlay; Ravikumar, M; Sathiyan, S; Ganesh, K M; Ponmalar, Y Retna; Varatharaj, C

    2016-01-01

    The advent of modern technologies in radiotherapy poses an increased challenge in the determination of dosimetric parameters of small fields that exhibit a high degree of uncertainty. Percent depth dose and beam profiles were acquired using different detectors in two different orientations. The parameters such as relative surface dose (D S), depth of dose maximum (D max), percentage dose at 10 cm (D 10), penumbral width, flatness, and symmetry were evaluated with different detectors. The dosimetric data were acquired for fields defined by jaws alone, multileaf collimator (MLC) alone, and by MLC while the jaws were positioned at 0, 0.25, 0.5, and 1.0 cm away from MLC leaf-end using a Varian linear accelerator with 6 MV photon beam. The accuracy in the measurement of dosimetric parameters with various detectors for three different field definitions was evaluated. The relative D S(38.1%) with photon field diode in parallel orientation was higher than electron field diode (EFD) (27.9%) values for 1 cm ×1 cm field. An overestimation of 5.7% and 8.6% in D 10 depth were observed for 1 cm ×1 cm field with RK ion chamber in parallel and perpendicular orientation, respectively, for the fields defined by MLC while jaw positioned at the edge of the field when compared to EFD values in parallel orientation. For this field definition, the in-plane penumbral widths obtained with ion chamber in parallel and perpendicular orientation were 3.9 mm, 5.6 mm for 1 cm ×1 cm field, respectively. Among all detectors used in the study, the unshielded diodes were found to be an appropriate choice of detector for the measurement of beam parameters in small fields. PMID:27051165

  1. The UV limits of life on extrasolar planets: an experiment with halophile archaeabacteria at different UV doses.

    NASA Astrophysics Data System (ADS)

    Abrevaya, X. C.; Adamo, H. P.; Cortó N, E.; Mauas, P. J. D.

    Terrestial-type planets around M stars are proposed as feasible places for development of life as we know it. Nevertheless many dMe stars emit large amounts of UV radiation during flares and it is unknown if these events could be deleterious for life. Since terrestrial biological systems are particularly vulnerable to this kind of radiation, this fact could set a limit for habitability. Organisms as halophile archaeabacteria were found in ancient evaporites on Earth. Evaporites have been detected in Martian meteorites, so these organisms are proposed as plausible inhabitants of Mars-like planets or other extrasolar planets. We examine the effect of UV-C on the halophile archaea Natrialba magadii. Results show that these organisms are able to survive at the UV doses tested.

  2. Evaluation of different doses of UV irradiation to loach eggs for genetic inactivation of the maternal genome.

    PubMed

    Fujimoto, Takafumi; Sakao, Suzu; Yamaha, Etsuro; Arai, Katsutoshi

    2007-08-01

    Genetic inactivation of the egg nucleus is an indispensable step in the production of androgenetic embryos in teleosts. However, few experimental studies have focused on determining the most effective means of achieving complete inactivation of the maternal genome. Here, we sought to identify the optimum conditions of ultraviolet (UV) irradiation for complete inactivation of the loach egg nucleus. Unfertilized eggs were UV irradiated from above with a dose in the range 0-200 mJ/cm2. Successful inactivation of the maternal genome was evaluated by the exclusive expression of a paternally inherited color phenotype. The presence or absence of putative maternal chromosome fragments was screened by flow cytometry of DNA content and by cytogenetic analysis. The majority of the larvae derived from irradiated eggs had an abnormal appearance. Haploid individuals were detected by measurement of DNA content flow cytometry and by chromosome counting in the groups that received more than 75 mJ/cm2 groups. Although the coefficient of variation of DNA content was apparently reduced in the 125-200 mJ/cm2 groups, chromosome fragments were still detected in all the groups from irradiated eggs. Inactivation of the egg nucleus was also histologically elucidated by the presence or absence of residual nuclear material in anuclear embryos that developed from UV-irradiated eggs fertilized with UV-irradiated sperm. Embryos that were completely or near-completely anuclear were found in the 150 and 200 mJ/cm2 groups. We conclude that the optimum UV dose for complete genetic inactivation of the egg nucleus is more than 150 mJ/cm2. PMID:17607702

  3. Low-intermediate dose testosterone replacement therapy by different pharmaceutical preparations improves frailty score in elderly hypogonadal hyperglycaemic patients.

    PubMed

    Strollo, Felice; Strollo, Giovanna; Morè, Massimo; Magni, Paolo; Macchi, Chiara; Masini, Maria Angela; Carucci, Iarba; Celotti, Fabio; Ruscica, Massimiliano; Gentile, Sandro

    2013-06-01

    An open-label follow-up study of low-to-intermediate dose testosterone replacement therapy (TRT) was conducted in 64 overweight patients (aged 65-75 years) with late onset hypogonadism (LOH) and increased fasting plasma glucose (FPG). Patients were subdivided into four treatment groups: oral testosterone (T) (T undecanoate, 80 mg/d), transmucosal T (60 mg/d), transdermal T (30 mg/d) or no treatment (control), and evaluated at 0 and 6 months. FPG, hemoglobin (Hb), prostate-specific antigen (PSA) and total T were measured and the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) index was calculated. Body mass index (BMI), waist circumference, fitness level (6-min walking test), Aging Males' Symptoms (AMS) scale, handgrip strength and energy expenditure with physical activity (Minnesota questionnaire for Leisure Time Physical Activity (LTPA)) were evaluated and a "frailty score" (based on: grip strength, gait speed and LTPA) was calculated. T levels increased in all treatment groups; the oral T group had values still in the hypogonadal range (5.9 ± 1.1 nmol/L). PSA and Hb concentrations did not change in any group. BMI, waist circumference, FPG and HOMA-IR improved in all T-treated groups after 6 months, with a greater effect seen with transmucosal and transdermal T compared with oral T. This study indicates that low-to-intermediate dose TRT may be safely utilized in LOH patients to ameliorate somatic and psychological frailty symptoms in association with improved anthropometric and glycometabolic parameters in aging, overweight men with LOH and impaired fasting glucose. PMID:23517433

  4. A critical study of different Monte Carlo scoring methods of dose average linear-energy-transfer maps calculated in voxelized geometries irradiated with clinical proton beams.

    PubMed

    Cortés-Giraldo, M A; Carabe, A

    2015-04-01

    We compare unrestricted dose average linear energy transfer (LET) maps calculated with three different Monte Carlo scoring methods in voxelized geometries irradiated with proton therapy beams with three different Monte Carlo scoring methods. Simulations were done with the Geant4 (Geometry ANd Tracking) toolkit. The first method corresponds to a step-by-step computation of LET which has been reported previously in the literature. We found that this scoring strategy is influenced by spurious high LET components, which relative contribution in the dose average LET calculations significantly increases as the voxel size becomes smaller. Dose average LET values calculated for primary protons in water with voxel size of 0.2 mm were a factor ~1.8 higher than those obtained with a size of 2.0 mm at the plateau region for a 160 MeV beam. Such high LET components are a consequence of proton steps in which the condensed-history algorithm determines an energy transfer to an electron of the material close to the maximum value, while the step length remains limited due to voxel boundary crossing. Two alternative methods were derived to overcome this problem. The second scores LET along the entire path described by each proton within the voxel. The third followed the same approach of the first method, but the LET was evaluated at each step from stopping power tables according to the proton kinetic energy value. We carried out microdosimetry calculations with the aim of deriving reference dose average LET values from microdosimetric quantities. Significant differences between the methods were reported either with pristine or spread-out Bragg peaks (SOBPs). The first method reported values systematically higher than the other two at depths proximal to SOBP by about 15% for a 5.9 cm wide SOBP and about 30% for a 11.0 cm one. At distal SOBP, the second method gave values about 15% lower than the others. Overall, we found that the third method gave the most consistent

  5. Role of shielding in modulating the effects of solar particle events: Monte Carlo calculation of absorbed dose and DNA complex lesions in different organs

    NASA Technical Reports Server (NTRS)

    Ballarini, F.; Biaggi, M.; De Biaggi, L.; Ferrari, A.; Ottolenghi, A.; Panzarasa, A.; Paretzke, H. G.; Pelliccioni, M.; Sala, P.; Scannicchio, D.; Zankl, M.; Townsend, L. W. (Principal Investigator)

    2004-01-01

    Distributions of absorbed dose and DNA clustered damage yields in various organs and tissues following the October 1989 solar particle event (SPE) were calculated by coupling the FLUKA Monte Carlo transport code with two anthropomorphic phantoms (a mathematical model and a voxel model), with the main aim of quantifying the role of the shielding features in modulating organ doses. The phantoms, which were assumed to be in deep space, were inserted into a shielding box of variable thickness and material and were irradiated with the proton spectra of the October 1989 event. Average numbers of DNA lesions per cell in different organs were calculated by adopting a technique already tested in previous works, consisting of integrating into "condensed-history" Monte Carlo transport codes--such as FLUKA--yields of radiobiological damage, either calculated with "event-by-event" track structure simulations, or taken from experimental works available in the literature. More specifically, the yields of "Complex Lesions" (or "CL", defined and calculated as a clustered DNA damage in a previous work) per unit dose and DNA mass (CL Gy-1 Da-1) due to the various beam components, including those derived from nuclear interactions with the shielding and the human body, were integrated in FLUKA. This provided spatial distributions of CL/cell yields in different organs, as well as distributions of absorbed doses. The contributions of primary protons and secondary hadrons were calculated separately, and the simulations were repeated for values of Al shielding thickness ranging between 1 and 20 g/cm2. Slight differences were found between the two phantom types. Skin and eye lenses were found to receive larger doses with respect to internal organs; however, shielding was more effective for skin and lenses. Secondary particles arising from nuclear interactions were found to have a minor role, although their relative contribution was found to be larger for the Complex Lesions than for the

  6. Different doses of intravenous Magnesium sulfate on cardiovascular changes following the laryngoscopy and tracheal intubation: A double-blind randomized controlled trial

    PubMed Central

    Honarmand, Azim; Safavi, Mohammadreza; Badiei, Sajad; Daftari-Fard, Neda

    2015-01-01

    Objective: Laryngoscopy and intratracheal intubation may cause acute hemodynamic instabilities due to catecholamine release. Magnesium sulfate (MgSO4) prevents catecholamine release and results in bradycardia and vasodilatation, so can be used to diminish complications of laryngoscopy and intubation in doses > 50 mg/kg. The aim of this study was to compare the different doses of MgSO4 used to improve cardiovascular instabilities due to laryngoscopy and intratracheal intubation. Methods: In this double-blind randomized controlled trial, 120 patients undergoing elective surgery were divided equally into four groups (n = 30) and received different doses of MgSO4 as case groups (Group I: 30 mg/kg, Group II: 40 mg/kg, Group III: 50 mg/kg) or the equal volume of normal saline as a control group. The patients’ hemodynamic status was recorded at baseline, before laryngoscopy and in 1, 3, 5, and 10 minutes after laryngoscopy. Bradycardia, tachycardia, hypertension, hypotension, ST-T changes, arrhythmias, and duration of extubation and laryngoscopy were also recorded. Findings: There was no significant difference in heart rate between four groups (Pbaseline = 0.46, Ppreoperation = 0.55, P1 min = 0.86, P3 min = 0.30, P5 min = 0.63, P10 min = 0.74). Systolic, diastolic and mean arterial pressures were statistically significant less at 1, 3, and 5 minutes after intubation in comparison with other times of following-up in the three groups received MgSO4 than the control group. Conclusion: The use of MgSO4 in doses less than 50 mg/kg can be effective to reduce cardiovascular instability related to laryngoscopy and tracheal intubation. PMID:25984545

  7. Quantification of Contralateral Breast Dose and Risk Estimate of Radiation-Induced Contralateral Breast Cancer Among Young Women Using Tangential Fields and Different Modes of Breathing

    SciTech Connect

    Zurl, Brigitte; Stranzl, Heidi; Winkler, Peter; Kapp, Karin Sigrid

    2013-02-01

    Purpose: Whole breast irradiation with deep-inspiration breath-hold (DIBH) technique among left-sided breast cancer patients significantly reduces cardiac irradiation; however, a potential disadvantage is increased incidental irradiation of the contralateral breast. Methods and Materials: Contralateral breast dose (CBD) was calculated by comparing 400 treatment plans of 200 left-sided breast cancer patients whose tangential fields had been planned on gated and nongated CT data sets. Various anatomic and field parameters were analyzed for their impact on CBD. For a subgroup of patients (aged {<=}45 years) second cancer risk in the contralateral breast (CB) was modeled by applying the linear quadratic model, compound models, and compound models considering dose-volume information (DVH). Results: The mean CBD was significantly higher in DIBH with 0.69 Gy compared with 0.65 Gy in normal breathing (P=.01). The greatest impact on CBD was due to a shift of the inner field margin toward the CB in DIBH (mean 0.4 cm; range, 0-2), followed by field size in magnitude. Calculation with different risk models for CBC revealed values of excess relative risk/Gy ranging from 0.48-0.65 vs 0.46-0.61 for DIBH vs normal breathing, respectively. Conclusion: Contralateral breast dose, although within a low dose range, was mildly but significantly increased in 200 treatment plans generated under gated conditions, predominately due to a shift in the medial field margin. Risk modeling for CBC among women aged {<=}45 years also pointed to a higher risk when comparing DIBH with normal breathing. This risk, however, was substantially lower in the model considering DVH information. We think that clinical decisions should not be affected by this small increase in CBD with DIBH because DIBH is effective in reducing the dose to the heart in all patients.

  8. DOSE-RESPONSE Relationships Between Whole-Body Vibration and Lumbar Disk DISEASE—A Field Study on 388 Drivers of Different Vehicles

    NASA Astrophysics Data System (ADS)

    Schwarze, S.; Notbohm, G.; Dupuis, H.; Hartung, E.

    1998-08-01

    In a longitudinal study, the dose-response relationships between long term occupational exposure to whole-body vibration and degenerative processes in the lumbar spine caused by the lumbar disks were examined. From 1990 to 1992, 388 vibration-exposed workers from different driving jobs were examined medically and by lumbar X-ray. For each individual, a history of all exposure conditions was recorded, and a cumulative vibration dose was calculated allowing comparisons between groups of low, middle, and high intensity of exposure. 310 subjects were selected for a follow-up four years later, of whom 90·6% (n=281) agreed to participate. In comparing the exposure groups, the results indicate that the limit value ofazw(8h)=0·8 m/s2should be reviewed. The best fit between the lifelong vibration dose and the occurrence of a lumbar syndrome was obtained by applying a daily reference ofazw(8h)=0·6 ms2as a limit value. The results became more distinct still when only those subjects were included in the statistical analysis who had had no lumbar symptoms up to the end of the first year of exposure. The prevalence of lumbar syndrome is 1·55 times higher in the highly exposed group when compared to the reference group with low exposure (CI95%=1·24/1·95). Calculating the cumulative incidence of new cases of lumbar syndrome in the follow-up period yields a relative risk ofRRMH=1·37 (CI95%=0·86/2·17) for the highly exposed group. It is concluded that the limit value for the calculation of an individual lifelong vibration dose should be based on a daily reference exposure ofazw(8h)=0·6 m/s2. With increasing dose it is more and more probable that cases of lumbar syndrome are caused by exposure to vibration.

  9. Dose-response effects of Lepidium meyenii (Maca) aqueous extract on testicular function and weight of different organs in adult rats.

    PubMed

    Chung, Francisco; Rubio, Julio; Gonzales, Carla; Gasco, Manuel; Gonzales, Gustavo F

    2005-04-01

    Lepidium meyenii (Brassicaceae) known as Maca grows exclusively between 4000 and 4500 m over the sea level in the Peruvian central Andes. The dried hypocotyls of Maca are traditionally used as food and for its supposed fertility-enhancing properties. A dose-response study was performed to determine the effect of 7 days oral administration of an aqueous lyophilized extract of Maca at 0.01-5 g/kg (corresponding to 0.022-11 g dry hypocotyls of Maca/kg) on body and different organ weights, stages of the seminiferous tubules, epididymal sperm count and motility, and serum testosterone and estradiol levels in rats. In doses up to 5 g extract/kg, no toxicity was observed. Almost all organ weights were similar in controls and in the Maca extract-treated groups. Seminal vesicles weight was significantly reduced at 0.01 and 0.10 g extract/kg. Maca increased in length of stages VII-VIII of the seminiferous tubules in a dose-response fashion, with highest response at 1.0 g/kg, while caput/corpus epididymal sperm count increased at the 1.0 g dose. Cauda epididymal sperm count, sperm motility, and serum estradiol level were not affected at any of the doses studied. Serum testosterone was lower at 0.10 g extract/kg. Low-seminal vesicle weights correlated with low-serum testosterone levels (R2=0.33; P<0.0001) and low-testosterone/estradiol ratio (R2=0.35; P<0.0001). Increase in epididymal sperm count was related to lengths of stages VII-VIII. Highest effect on stages VII-VIII of the seminiferous tubules was observed at 1.0 g Maca aqueous extract/kg. The present study demonstrated that Maca extract in doses up to 5 g/kg (equivalent to the intake of 770 g hypocotyls in a man of 70 kg) was safe and that higher effect on reproductive parameters was elicited with a dose of 1 g extract/kg corresponding to 2.2 g dry Maca hypocotyls/kg. PMID:15763375

  10. Quantification of absorption, retention and elimination of two different oral doses of vitamin A in Zambian boys using accelerator mass spectrometry

    SciTech Connect

    Aklamati, E K; Mulenga, M; Dueker, S R; Buchholz, B A; Peerson, J M; Kafwembe, E; Brown, K H; Haskell, M J

    2009-10-12

    A recent survey indicated that high-dose vitamin A supplements (HD-VAS) had no apparent effect on vitamin A (VA) status of Zambian children <5 y of age. To explore possible reasons for the lack of response to HD-VAS among Zambian children, we quantified the absorption, retention, and urinary elimination of either a single HDVAS (60 mg) or a smaller dose of stable isotope (SI)-labeled VA (5 mg), which was used to estimate VA pool size, in 3-4 y old Zambian boys (n = 4 for each VA dose). A 25 nCi tracer dose of [{sup 14}C{sub 2}]-labeled VA was co-administered with the HD-VAS or SI-labeled VA, and 24-hr stool and urine samples were collected for 3 and 7 consecutive days, respectively, and 24-hr urine samples at 4 later time points. Accelerator Mass Spectrometry (AMS) was used to measure the cumulative excretion of {sup 14}C in stool and urine 3d after dosing to estimate, respectively, absorption and retention of the VAS and SI-labeled VA. The urinary elimination rate (UER) was estimated by plotting {sup 14}C in urine vs. time, and fitting an exponential equation to the data. Estimates of mean absorption, retention and the UER were 83.8 {+-} 7.1%, 76.3 {+-} 6.7%, and 1.9 {+-} 0.6%/d, respectively, for the HD-VAS and 76.5 {+-} 9.5%, 71.1 {+-} 9.4%, and 1.8 {+-} 1.2%/d, respectively for the smaller dose of SI-labeled VA. Estimates of absorption, retention and the UER did not differ by size of the VA dose administered (P=0.26, 0.40, 0.88, respectively). Estimated absorption and retention were negatively associated with reported fever (P=0.011) and malaria (P =0.010). HD-VAS and SI-labeled VA were adequately absorbed, retained and utilized in apparently healthy Zambian preschool-age boys, although absorption and retention may be affected by recent infections.

  11. Models and Monte Carlo simulations of GCR and SPE organ doses with different shielding, based on the FLUKA code coupled with anthropomorphic phantoms

    NASA Astrophysics Data System (ADS)

    Ballarini, F.; Fluka-Phantoms Team

    Astronauts' exposure to space radiation is of major concern for long-term missions, especially for those in deep space such as a possible mission to Mars. Shielding optimization is therefore a crucial issue, and simulations based on radiation transport codes coupled with anthropomorphic model phantoms can be of great help. In this work, carried out with the FLUKA MC code and two anthropomorphic phantoms (a mathematical model and a "voxel" model), distributions of physical (i.e. absorbed), equivalent and "biological" dose in the various tissues and organs were calculated in different shielding conditions for solar minimum and solar maximum GCR spectra, as well as for the August 1972 Solar Particle Event. The biological dose was modeled as the average number of "Complex Lesions" (CL) per cell in a given organ. CLs are clustered DNA breaks previously calculated with "event-by-event" track structure simulations and integrated in the condensed-history FLUKA code. This approach is peculiar in that it is an example of a mechanistically-based quantification of the ionizing radiation action in biological targets; indeed CLs have been shown to play a fundamental role in chromosome aberration induction. The contributions of primary particles and secondary hadrons were calculated separately, thus allowing quantification of the role of nuclear reactions in the shield and in the human body. As expected, the doses calculated for the 1972 SPE decrease dramatically with increasing the Al shielding; nuclear reactions were found to be of minor importance, although their role is higher for internal organs and large shielding. An Al shield thickness of 10 g/cm2 appears sufficient to respect the 30-day deterministic limits recommended by NCRP for missions in Low Earth Orbit. In contrast with the results obtained for SPE, GCR doses to internal organs are not significantly lower than skin doses. However, the relative contribution of secondary hadrons was found to be more important for

  12. Absolute calibration in the 1750 - 3350 A region

    NASA Technical Reports Server (NTRS)

    Strongylis, G. J.; Bohlin, R. C.

    1977-01-01

    The absolute flux measurements in the rocket ultraviolet made by Bohlin, Frimout, and Lillie (BFL) are revised using a more correct treatment of the air extinction that enters the air calibration of their instrument. The absorption by molecular oxygen and ozone, Rayleigh scattering, and extinction by aerosols is tabulated for general use in ultraviolet calibrations performed in air. The revised absolute flux of eta UMa and final fluxes for alpha Lyr and zeta Oph are presented in the 1750-3350 A region. The absolute flux of the star eta UMa is compared to four other independent determinations in the 1200-3400 A region and a maximum difference of 35% is found near 1500 A between the OAO-2 and Apollo 17 fluxes. The rocket measurements of BFL, the ANS and TD-1 satellite data, and the Apollo 17 data are compared to the ultraviolet fluxes from the OAO-2, demonstrating a photometric reproducibility of about + or - 3 percent. Therefore, all four sets of spectrophotometry can be reduced to a common absolute scale.

  13. Absolute phase effects on CPMG-type pulse sequences

    NASA Astrophysics Data System (ADS)

    Mandal, Soumyajit; Oh, Sangwon; Hürlimann, Martin D.

    2015-12-01

    We describe and analyze the effects of transients within radio-frequency (RF) pulses on multiple-pulse NMR measurements such as the well-known Carr-Purcell-Meiboom-Gill (CPMG) sequence. These transients are functions of the absolute RF phases at the beginning and end of the pulse, and are thus affected by the timing of the pulse sequence with respect to the period of the RF waveform. Changes in transients between refocusing pulses in CPMG-type sequences can result in signal decay, persistent oscillations, changes in echo shape, and other effects. We have explored such effects by performing experiments in two different low-frequency NMR systems. The first uses a conventional tuned-and-matched probe circuit, while the second uses an ultra-broadband un-tuned or non-resonant probe circuit. We show that there are distinct differences between the absolute phase effects in these two systems, and present simple models that explain these differences.

  14. Accompanying of parameters of color, gloss and hardness on polymeric films coated with pigmented inks cured by different radiation doses of ultraviolet light

    NASA Astrophysics Data System (ADS)

    Bardi, Marcelo Augusto Gonçalves; Machado, Luci Diva Brocardo

    2012-09-01

    In the search for alternatives to traditional paint systems solvent-based, the curing process of polymer coatings by ultraviolet light (UV) has been widely studied and discussed, especially because of their high content of solids and null emission of VOC. In UV-curing technology, organic solvents are replaced by reactive diluents, such as monomers. This paper aims to investigate variations on color, gloss and hardness of print inks cured by different UV radiation doses. The ratio pigment/clear coating was kept constant. The clear coating presented higher average values for König hardness than pigmented ones, indicating that UV-light absorption has been reduced by the presence of pigments. Besides, they have indicated a slight variation in function of cure degree for the studied radiation doses range. The gloss loss related to UV light exposition allows inferring that some degradation occurred at the surface of print ink films.

  15. Cone Beam CT vs. Fan Beam CT: A Comparison of Image Quality and Dose Delivered Between Two Differing CT Imaging Modalities

    PubMed Central

    Weidlich, Georg A.

    2016-01-01

    A comparison of image quality and dose delivered between two differing computed tomography (CT) imaging modalities—fan beam and cone beam—was performed. A literature review of quantitative analyses for various image quality aspects such as uniformity, signal-to-noise ratio, artifact presence, spatial resolution, modulation transfer function (MTF), and low contrast resolution was generated. With these aspects quantified, cone beam computed tomography (CBCT) shows a superior spatial resolution to that of fan beam, while fan beam shows a greater ability to produce clear and anatomically correct images with better soft tissue differentiation. The results indicate that fan beam CT produces superior images to that of on-board imaging (OBI) cone beam CT systems, while providing a considerably less dose to the patient. PMID:27752404

  16. [Radiolysis of liposomes, of solutions of ferrous sulphate and of albumin mixed by gamma-neutron radiation at different dose rates].

    PubMed

    Riabchenko, N I; Ul'ianenko, S E; Riabchenko, V I; Dzikovskaia, L A; Ivannik, V P; Sokolov, V A

    2005-01-01

    Solutions of the ferrous sulfate, of the albumin and of the suspension of liposomes were irradiated by mixed gamma-neutron radiation (fission spectrum neutrons, contribution of gamma-component to the absorbed dose up to 20%) at the pulse reactor BARS-6 with single-pulse (duration 100 micros) or continuous radiation (duration 60 min). It was shown, that after the pulse irradiation the concentration of the malonic dialdehyde in liposomes was in 3-4 times higher than after the continuous radiation at equal absorbed doses (p < 0.05). On the contrary, the irradiation of the liposomes suspension as well as of the solutions of the ferrous sulfate and of the albumin in a mode of single-pulse or of continuous mode did not reveal the statistically significant differences in the production of Fe3+ ions and of peroxides of the albumin for two mode of the radiation action. PMID:16304771

  17. Day and Night GSH and MDA Levels in Healthy Adults and Effects of Different Doses of Melatonin on These Parameters.

    PubMed

    Chakravarty, Shilpa; Rizvi, Syed Ibrahim

    2011-01-01

    The pineal secretory product melatonin (chemically, N-acetyl-5-methoxytryptamine) acts as an effective antioxidant and free-radical scavenger and plays an important role in several physiological functions such as sleep induction, immunomodulation, cardiovascular protection, thermoregulation, neuroprotection, tumor-suppression and oncostasis. Membrane lipid-peroxidation in terms of malondialdehyde (MDA) and intracellular glutathione (GSH) is considered to be a reliable marker of oxidative stress. The present work was undertaken to study the modulating effect of melatonin on MDA and GSH in human erythrocytes during day and night. Our observation shows the modulation of these two biomarkers by melatonin, and this may have important therapeutic implications. In vitro dose-dependent effect of melatonin also showed variation during day and night. We explain our observations on the basis of melatonin's antioxidative function and its effect on the fluidity of plasma membrane of red blood cells. Rhythmic modulation of MDA and GSH contents emphasized the role of melatonin as an antioxidant and its function against oxidative stress.

  18. Changing the Tune: The Structure of the Input Affects Infants' Use of Absolute and Relative Pitch

    ERIC Educational Resources Information Center

    Saffran, Jenny R.; Reeck, Karelyn; Niebuhr, Aimee; Wilson, Diana

    2005-01-01

    Sequences of notes contain several different types of pitch cues, including both absolute and relative pitch information. What factors determine which of these cues are used when learning about tone sequences? Previous research suggests that infants tend to preferentially process absolute pitch patterns in continuous tone sequences, while other…

  19. An Integrated Model of Choices and Response Times in Absolute Identification

    ERIC Educational Resources Information Center

    Brown, Scott D.; Marley, A. A. J.; Donkin, Christopher; Heathcote, Andrew

    2008-01-01

    Recent theoretical developments in the field of absolute identification have stressed differences between relative and absolute processes, that is, whether stimulus magnitudes are judged relative to a shorter term context provided by recently presented stimuli or a longer term context provided by the entire set of stimuli. The authors developed a…

  20. The Relation between the Absolute Level of Parenting and Differential Parental Treatment with Adolescent Siblings' Adjustment

    ERIC Educational Resources Information Center

    Tamrouti-Makkink, Ilse D.; Dubas, Judith Semon; Gerris, Jan R. M.; van Aken, Marcel A. G.

    2004-01-01

    Background: The present study extends existing studies on the role of differential parental treatment in explaining individual differences in adolescent problem behaviors above the absolute level of parenting and clarifies the function of gender of the child, birth rank and gender constellation of the sibling dyads. Method: The absolute level of…

  1. Jasminum flexile flower absolute from India--a detailed comparison with three other jasmine absolutes.

    PubMed

    Braun, Norbert A; Kohlenberg, Birgit; Sim, Sherina; Meier, Manfred; Hammerschmidt, Franz-Josef

    2009-09-01

    Jasminum flexile flower absolute from the south of India and the corresponding vacuum headspace (VHS) sample of the absolute were analyzed using GC and GC-MS. Three other commercially available Indian jasmine absolutes from the species: J. sambac, J. officinale subsp. grandiflorum, and J. auriculatum and the respective VHS samples were used for comparison purposes. One hundred and twenty-one compounds were characterized in J. flexile flower absolute, with methyl linolate, benzyl salicylate, benzyl benzoate, (2E,6E)-farnesol, and benzyl acetate as the main constituents. A detailed olfactory evaluation was also performed.

  2. SU-E-I-31: Differences Observed in Radiation Doses Across 2 Similar CT Scanners From Adult Brain-Neck CT Angiography

    SciTech Connect

    Fujii, K; McMillan, K; Bostani, M; Cagnon, C; McNitt-Gray, M

    2015-06-15

    Purpose: The aim of this study is to evaluate the difference in radiation doses from adult Brain-Neck CT angiography (CTA) between two CT scanners. Methods: We collected CT dose index data (CTDIvol, DLP) from adult Brain-Neck CTA performed with two CT scanners (Sensation 64 (S64) and Definition AS (AS), Siemens Healthcare) performed at two of our facilities from Jan 1st to Dec 31th, 2014. X-ray dose management software (Radmetrics, Bayer Healthcare) was used to mine these data. All exams were performed with Tube Current Modulation (Care Dose 4D), tube voltage of 120 kVp, quality reference mAs of 300, beam collimation of 64*0.6 mm. The rotation time was set to 0.5 sec for S64 and 1.0 sec for AS. We also scanned an anthropomorphic skull and chest phantom under routine Brain-Neck CTA protocol with the two scanners and extracted the tube current values from the raw projection data. Results: The mean CTDIvol and DLP in Brain-Neck CTA was 72 mGy and 2554 mGy*cm for AS, which was substantially larger than the mean values of 46 mGy and 1699 mGy*cm for S64. The maximum tube current was 583 mA for most cases on the S64 while the maximum was 666 mA for AS even though the rotation time set for AS was 1.0 sec. Measurements obtained with the anthropomorphic phantom showed that the tube current reached 583 mA at the shoulder region for S64 while it reached to 666 mA for AS. Conclusion: The results of this study showed that substantially different CT doses can Result from Brain-Neck CTA protocols even when similar scanners and similar settings are used. Though both scanners have a similar maximum mA rating, differences in mA were observed through the shoulders, resulting in substantially different CTDIvol values.

  3. Body fat loss and compensatory mechanisms in response to different doses of aerobic exercise--a randomized controlled trial in overweight sedentary males.

    PubMed

    Rosenkilde, Mads; Auerbach, Pernille; Reichkendler, Michala Holm; Ploug, Thorkil; Stallknecht, Bente Merete; Sjödin, Anders

    2012-09-15

    The amount of weight loss induced by exercise is often disappointing. A diet-induced negative energy balance triggers compensatory mechanisms, e.g., lower metabolic rate and increased appetite. However, knowledge about potential compensatory mechanisms triggered by increased aerobic exercise is limited. A randomized controlled trial was performed in healthy, sedentary, moderately overweight young men to examine the effects of increasing doses of aerobic exercise on body composition, accumulated energy balance, and the degree of compensation. Eighteen participants were randomized to a continuous sedentary control group, 21 to a moderate-exercise (MOD; 300 kcal/day), and 22 to a high-exercise (HIGH; 600 kcal/day) group for 13 wk, corresponding to ∼30 and 60 min of daily aerobic exercise, respectively. Body weight (MOD: -3.6 kg, P < 0.001; HIGH: -2.7 kg, P = 0.01) and fat mass (MOD: -4.0 kg, P < 0.001 and HIGH: -3.8 kg, P < 0.001) decreased similarly in both exercise groups. Although the exercise-induced energy expenditure in HIGH was twice that of MOD, the resulting accumulated energy balance, calculated from changes in body composition, was not different (MOD: -39.6 Mcal, HIGH: -34.3 Mcal, not significant). Energy balance was 83% more negative than expected in MOD, while it was 20% less negative than expected in HIGH. No statistically significant changes were found in energy intake or nonexercise physical activity that could explain the different compensatory responses associated with 30 vs. 60 min of daily aerobic exercise. In conclusion, a similar body fat loss was obtained regardless of exercise dose. A moderate dose of exercise induced a markedly greater than expected negative energy balance, while a higher dose induced a small but quantifiable degree of compensation.

  4. Absolute Radiometric Calibration of KOMPSAT-3A

    NASA Astrophysics Data System (ADS)

    Ahn, H. Y.; Shin, D. Y.; Kim, J. S.; Seo, D. C.; Choi, C. U.

    2016-06-01

    This paper presents a vicarious radiometric calibration of the Korea Multi-Purpose Satellite-3A (KOMPSAT-3A) performed by the Korea Aerospace Research Institute (KARI) and the Pukyong National University Remote Sensing Group (PKNU RSG) in 2015.The primary stages of this study are summarized as follows: (1) A field campaign to determine radiometric calibrated target fields was undertaken in Mongolia and South Korea. Surface reflectance data obtained in the campaign were input to a radiative transfer code that predicted at-sensor radiance. Through this process, equations and parameters were derived for the KOMPSAT-3A sensor to enable the conversion of calibrated DN to physical units, such as at-sensor radiance or TOA reflectance. (2) To validate the absolute calibration coefficients for the KOMPSAT-3A sensor, we performed a radiometric validation with a comparison of KOMPSAT-3A and Landsat-8 TOA reflectance using one of the six PICS (Libya 4). Correlations between top-of-atmosphere (TOA) radiances and the spectral band responses of the KOMPSAT-3A sensors at the Zuunmod, Mongolia and Goheung, South Korea sites were significant for multispectral bands. The average difference in TOA reflectance between KOMPSAT-3A and Landsat-8 image over the Libya 4, Libya site in the red-green-blue (RGB) region was under 3%, whereas in the NIR band, the TOA reflectance of KOMPSAT-3A was lower than the that of Landsat-8 due to the difference in the band passes of two sensors. The KOMPSAT-3Aensor includes a band pass near 940 nm that can be strongly absorbed by water vapor and therefore displayed low reflectance. Toovercome this, we need to undertake a detailed analysis using rescale methods, such as the spectral bandwidth adjustment factor.

  5. Universal Cosmic Absolute and Modern Science

    NASA Astrophysics Data System (ADS)

    Kostro, Ludwik

    The official Sciences, especially all natural sciences, respect in their researches the principle of methodic naturalism i.e. they consider all phenomena as entirely natural and therefore in their scientific explanations they do never adduce or cite supernatural entities and forces. The purpose of this paper is to show that Modern Science has its own self-existent, self-acting, and self-sufficient Natural All-in Being or Omni-Being i.e. the entire Nature as a Whole that justifies the scientific methodic naturalism. Since this Natural All-in Being is one and only It should be considered as the own scientifically justified Natural Absolute of Science and should be called, in my opinion, the Universal Cosmic Absolute of Modern Science. It will be also shown that the Universal Cosmic Absolute is ontologically enormously stratified and is in its ultimate i.e. in its most fundamental stratum trans-reistic and trans-personal. It means that in its basic stratum. It is neither a Thing or a Person although It contains in Itself all things and persons with all other sentient and conscious individuals as well, On the turn of the 20th century the Science has begun to look for a theory of everything, for a final theory, for a master theory. In my opinion the natural Universal Cosmic Absolute will constitute in such a theory the radical all penetrating Ultimate Basic Reality and will substitute step by step the traditional supernatural personal Absolute.

  6. Absolute Plate Velocities from Seismic Anisotropy

    NASA Astrophysics Data System (ADS)

    Kreemer, Corné; Zheng, Lin; Gordon, Richard

    2015-04-01

    The orientation of seismic anisotropy inferred beneath plate interiors may provide a means to estimate the motions of the plate relative to the sub-asthenospheric mantle. Here we analyze two global sets of shear-wave splitting data, that of Kreemer [2009] and an updated and expanded data set, to estimate plate motions and to better understand the dispersion of the data, correlations in the errors, and their relation to plate speed. We also explore the effect of using geologically current plate velocities (i.e., the MORVEL set of angular velocities [DeMets et al. 2010]) compared with geodetically current plate velocities (i.e., the GSRM v1.2 angular velocities [Kreemer et al. 2014]). We demonstrate that the errors in plate motion azimuths inferred from shear-wave splitting beneath any one tectonic plate are correlated with the errors of other azimuths from the same plate. To account for these correlations, we adopt a two-tier analysis: First, find the pole of rotation and confidence limits for each plate individually. Second, solve for the best fit to these poles while constraining relative plate angular velocities to consistency with the MORVEL relative plate angular velocities. The SKS-MORVEL absolute plate angular velocities (based on the Kreemer [2009] data set) are determined from the poles from eight plates weighted proportionally to the root-mean-square velocity of each plate. SKS-MORVEL indicates that eight plates (Amur, Antarctica, Caribbean, Eurasia, Lwandle, Somalia, Sundaland, and Yangtze) have angular velocities that differ insignificantly from zero. The net rotation of the lithosphere is 0.25±0.11° Ma-1 (95% confidence limits) right-handed about 57.1°S, 68.6°E. The within-plate dispersion of seismic anisotropy for oceanic lithosphere (σ=19.2° ) differs insignificantly from that for continental lithosphere (σ=21.6° ). The between-plate dispersion, however, is significantly smaller for oceanic lithosphere (σ=7.4° ) than for continental

  7. WE-E-BRE-06: High-Dose Microbeam Radiation Induces Different Responses in Tumor Microenvironment Compared to Conventional Seamless Radiation in Window Chamber Tumor Models

    SciTech Connect

    Chang, S; Zhang, J; Hadsell, M; Fontanella, A; Schroeder, T; Palmer, G; Dewhirst, M; Boss, M; Berman, K

    2014-06-15

    Purpose: Microbeam radiation therapy and GRID therapy are different forms of Spatially-Fractioned Radiation Therapy (SFRT) that is fundamentally different from the conventional seamless and temporally fractionated radiation therapy. SFRT is characterized by a ultra-high dose (10s –100s Gy) dose single treatment with drastic inhomogeneity pattern of given spatial frequencies. Preclinical and limited clinical studies have shown that the SFRT treatments may offer significant improvements in reducing treatment toxicity, especially for those patients who have not benefited from the state-of-the-art radiation therapy approaches. This preliminary study aims to elucidate the underlying working mechanisms of SFRT, which currently remains poorly understood. Methods: A genetically engineered 4T1 murine mammary carcinoma cell line and nude mice skin fold window chamber were used. A nanotechnology-based 160kV x-ray irradiator delivered 50Gy (entrance dose) single treatments of microbeam or seamless radiation. Animals were in 3 groups: mock, seamless radiation, and 300μm microbeam radiation. The windows were imaged using a hyperspectral system to capture total hemoglobin/saturation, GFP fluorescence emission, RFP fluorescence emission, and vessel density at 9 time points up to 7 days post radiation. Results: We found unique physiologic changes in different tumor/normal tissue regions and differential effects between seamless and microbeam treatments. They include 1) compared to microbeam and mock radiation seamless radiation damaged more microvasculature in tumor-surrounding normal tissue, 2) a pronounced angiogenic effect was observed with vascular proliferation in the microbeam irradiated portion of the tumor days post treatment (no such effect observed in seamless and mock groups), and 3) a notable change in tumor vascular orientation was observed where vessels initially oriented parallel to the beam length were replaced by vessels running perpendicular to the irradiation

  8. Absolute Gravity Datum in the Age of Cold Atom Gravimeters

    NASA Astrophysics Data System (ADS)

    Childers, V. A.; Eckl, M. C.

    2014-12-01

    increase in accuracy. Our presentation will also explore the impact of such an instrument on our theory of how to constrain the gravity datum and on how to ensure stability, repeatability, and reproducibility across different absolute gravimeter systems.

  9. GNSS Absolute Antenna Calibration at the National Geodetic Survey

    NASA Astrophysics Data System (ADS)

    Mader, G. L.; Bilich, A. L.; Geoghegan, C.

    2011-12-01

    Geodetic GNSS applications routinely demand millimeter precision and extremely high levels of accuracy. To achieve these accuracies, measurement and instrument biases at the centimeter to millimeter level must be understood. One of these biases is the antenna phase center, the apparent point of signal reception for a GNSS antenna. It has been well established that phase center patterns differ between antenna models and manufacturers; additional research suggests that the addition of a radome or the choice of antenna mount can significantly alter those a priori phase center patterns. For the more demanding GNSS positioning applications and especially in cases of mixed-antenna networks, it is all the more important to know antenna phase center variations as a function of both elevation and azimuth in the antenna reference frame and incorporate these models into analysis software. To help meet the needs of the high-precision GNSS community, the National Geodetic Survey (NGS) now operates an absolute antenna calibration facility. Located in Corbin, Virginia, this facility uses field measurements and actual GNSS satellite signals to quantitatively determine the carrier phase advance/delay introduced by the antenna element. The NGS facility was built to serve traditional NGS constituents such as the surveying and geodesy communities, however calibration services are open and available to all GNSS users as the calibration schedule permits. All phase center patterns computed by this facility will be publicly available and disseminated in both the ANTEX and NGS formats. We describe the NGS calibration facility, and discuss the observation models and strategy currently used to generate NGS absolute calibrations. We demonstrate that NGS absolute phase center variation (PCV) patterns are consistent with published values determined by other absolute antenna calibration facilities, and compare absolute calibrations to the traditional NGS relative calibrations.

  10. Quantum theory allows for absolute maximal contextuality

    NASA Astrophysics Data System (ADS)

    Amaral, Barbara; Cunha, Marcelo Terra; Cabello, Adán

    2015-12-01

    Contextuality is a fundamental feature of quantum theory and a necessary resource for quantum computation and communication. It is therefore important to investigate how large contextuality can be in quantum theory. Linear contextuality witnesses can be expressed as a sum S of n probabilities, and the independence number α and the Tsirelson-like number ϑ of the corresponding exclusivity graph are, respectively, the maximum of S for noncontextual theories and for the theory under consideration. A theory allows for absolute maximal contextuality if it has scenarios in which ϑ /α approaches n . Here we show that quantum theory allows for absolute maximal contextuality despite what is suggested by the examination of the quantum violations of Bell and noncontextuality inequalities considered in the past. Our proof is not constructive and does not single out explicit scenarios. Nevertheless, we identify scenarios in which quantum theory allows for almost-absolute-maximal contextuality.

  11. Absolute calibration in vivo measurement systems

    SciTech Connect

    Kruchten, D.A.; Hickman, D.P.

    1991-02-01

    Lawrence Livermore National Laboratory (LLNL) is currently investigating a new method for obtaining absolute calibration factors for radiation measurement systems used to measure internally deposited radionuclides in vivo. Absolute calibration of in vivo measurement systems will eliminate the need to generate a series of human surrogate structures (i.e., phantoms) for calibrating in vivo measurement systems. The absolute calibration of in vivo measurement systems utilizes magnetic resonance imaging (MRI) to define physiological structure, size, and composition. The MRI image provides a digitized representation of the physiological structure, which allows for any mathematical distribution of radionuclides within the body. Using Monte Carlo transport codes, the emission spectrum from the body is predicted. The in vivo measurement equipment is calibrated using the Monte Carlo code and adjusting for the intrinsic properties of the detection system. The calibration factors are verified using measurements of existing phantoms and previously obtained measurements of human volunteers. 8 refs.

  12. Stimulus probability effects in absolute identification.

    PubMed

    Kent, Christopher; Lamberts, Koen

    2016-05-01

    This study investigated the effect of stimulus presentation probability on accuracy and response times in an absolute identification task. Three schedules of presentation were used to investigate the interaction between presentation probability and stimulus position within the set. Data from individual participants indicated strong effects of presentation probability on both proportion correct and response times. The effects were moderated by the ubiquitous stimulus position effect. The accuracy and response time data were predicted by an exemplar-based model of perceptual cognition (Kent & Lamberts, 2005). The bow in discriminability was also attenuated when presentation probability for middle items was relatively high, an effect that will constrain future model development. The study provides evidence for item-specific learning in absolute identification. Implications for other theories of absolute identification are discussed. (PsycINFO Database Record

  13. Quantitative standards for absolute linguistic universals.

    PubMed

    Piantadosi, Steven T; Gibson, Edward

    2014-01-01

    Absolute linguistic universals are often justified by cross-linguistic analysis: If all observed languages exhibit a property, the property is taken to be a likely universal, perhaps specified in the cognitive or linguistic systems of language learners and users. In many cases, these patterns are then taken to motivate linguistic theory. Here, we show that cross-linguistic analysis will very rarely be able to statistically justify absolute, inviolable patterns in language. We formalize two statistical methods--frequentist and Bayesian--and show that in both it is possible to find strict linguistic universals, but that the numbers of independent languages necessary to do so is generally unachievable. This suggests that methods other than typological statistics are necessary to establish absolute properties of human language, and thus that many of the purported universals in linguistics have not received sufficient empirical justification.

  14. Absolute photoacoustic thermometry in deep tissue.

    PubMed

    Yao, Junjie; Ke, Haixin; Tai, Stephen; Zhou, Yong; Wang, Lihong V

    2013-12-15

    Photoacoustic thermography is a promising tool for temperature measurement in deep tissue. Here we propose an absolute temperature measurement method based on the dual temperature dependences of the Grüneisen parameter and the speed of sound in tissue. By taking ratiometric measurements at two adjacent temperatures, we can eliminate the factors that are temperature irrelevant but difficult to correct for in deep tissue. To validate our method, absolute temperatures of blood-filled tubes embedded ~9 mm deep in chicken tissue were measured in a biologically relevant range from 28°C to 46°C. The temperature measurement accuracy was ~0.6°C. The results suggest that our method can be potentially used for absolute temperature monitoring in deep tissue during thermotherapy.

  15. Molecular iodine absolute frequencies. Final report

    SciTech Connect

    Sansonetti, C.J.

    1990-06-25

    Fifty specified lines of {sup 127}I{sub 2} were studied by Doppler-free frequency modulation spectroscopy. For each line the classification of the molecular transition was determined, hyperfine components were identified, and one well-resolved component was selected for precise determination of its absolute frequency. In 3 cases, a nearby alternate line was selected for measurement because no well-resolved component was found for the specified line. Absolute frequency determinations were made with an estimated uncertainty of 1.1 MHz by locking a dye laser to the selected hyperfine component and measuring its wave number with a high-precision Fabry-Perot wavemeter. For each line results of the absolute measurement, the line classification, and a Doppler-free spectrum are given.

  16. Systematic review using meta-analyses to estimate dose-response relationships between iodine intake and biomarkers of iodine status in different population groups.

    PubMed

    Ristić-Medić, Danijela; Dullemeijer, Carla; Tepsić, Jasna; Petrović-Oggiano, Gordana; Popović, Tamara; Arsić, Aleksandra; Glibetić, Marija; Souverein, Olga W; Collings, Rachel; Cavelaars, Adriënne; de Groot, Lisette; van't Veer, Pieter; Gurinović, Mirjana

    2014-03-01

    The objective of this systematic review was to identify studies investigating iodine intake and biomarkers of iodine status, to assess the data of the selected studies, and to estimate dose-response relationships using meta-analysis. All randomized controlled trials, prospective cohort studies, nested case-control studies, and cross-sectional studies that supplied or measured dietary iodine and measured iodine biomarkers were included. The overall pooled regression coefficient (β) and the standard error of β were calculated by random-effects meta-analysis on a double-log scale, using the calculated intake-status regression coefficient (β) for each individual study. The results of pooled randomized controlled trials indicated that the doubling of dietary iodine intake increased urinary iodine concentrations by 14% in children and adolescents, by 57% in adults and the elderly, and by 81% in pregnant women. The dose-response relationship between iodine intake and biomarkers of iodine status indicated a 12% decrease in thyroid-stimulating hormone and a 31% decrease in thyroglobulin in pregnant women. The model of dose-response quantification used to describe the relationship between iodine intake and biomarkers of iodine status may be useful for providing complementary evidence to support recommendations for iodine intake in different population groups.

  17. Development of TV003/TV005, a single dose, highly immunogenic live attenuated dengue vaccine; what makes this vaccine different from the Sanofi-Pasteur CYD™ vaccine?

    PubMed

    Whitehead, Stephen S

    2016-01-01

    Dengue is caused by four serotype-distinct dengue viruses (DENVs), and developing a multivalent vaccine against dengue has not been straightforward since partial immunity to DENV may predispose to more severe disease upon subsequent DENV infection. The vaccine that is furthest along in development is CYD™, a live attenuated tetravalent vaccine (LATV) produced by Sanofi Pasteur. Although the multi-dose vaccine demonstrated protection against severe dengue, its overall efficacy was limited by DENV serotype, serostatus at vaccination, region and age. The National Institute of Allergy and Infectious Diseases has developed the LATV dengue vaccines TV003/TV005. A single dose of either TV003 or TV005 induced seroconversion to four DENV serotypes in 74-92% (TV003) and 90% (TV005) of flavivirus seronegative adults and elicited near-sterilizing immunity to a second dose of vaccine administered 6-12 months later. The important differences in the structure, infectivity and immune responses to TV003/TV005 are compared with CYD™. PMID:26559731

  18. Ecological half-time and effective dose from chernobyl debris and from nuclear weapons fallout of 137Cs as measured in different Swedish populations.

    PubMed

    Rääf, C L; Hubbard, L; Falk, R; Agren, G; Vesanen, R

    2006-05-01

    The fallout in Sweden of radiocesium from nuclear weapons tests during the 1960's (137Cs) and from the Chernobyl accident in 1986 (134Cs and 137Cs) has transferred to humans through different ecological pathways. Data from whole-body burden measurements of 134Cs, 137Cs, and 40K in various Swedish populations between 1964 and 2002 have been compiled. This database enables an evaluation of the temporal and geographical dependence of the transfer of radiocesium from ground deposition to humans and the associated absorbed dose. The body burdens of 137Cs gradually decrease after the peak values reached in 1965 from nuclear weapons fallout and in 1987 from the Chernobyl fallout, but at a varying rate depending on the population. Assuming a dual exponential decrease, a short-term component of typically 1-2 y and a long-term component of 5-10 y are found in urban populations in Sweden. Among reindeer herders and hunters the effective ecological half-time is mono-exponential with a half-time of 5-7 y. The estimated time-integrated effective dose to an individual during a period of 50 y from the Chernobyl fallout is, on average, approximately 10 mSv for reindeer herders, which is 10-100 times higher than the estimated dose received by urban populations in the three major Swedish urban areas (Malmö, Göteborg, and Stockholm).

  19. Utilising pseudo-CT data for dose calculation and plan optimization in adaptive radiotherapy.

    PubMed

    Whelan, Brendan; Kumar, Shivani; Dowling, Jason; Begg, Jarrad; Lambert, Jonathan; Lim, Karen; Vinod, Shalini K; Greer, Peter B; Holloway, Lois

    2015-12-01

    To quantify the dose calculation error and resulting optimization uncertainty caused by performing inverse treatment planning on inaccurate electron density data (pseudo-CT) as needed for adaptive radiotherapy and Magnetic Resonance Imaging (MRI) based treatment planning. Planning Computer Tomography (CT) data from 10 cervix cancer patients was used to generate 4 pseudo-CT data sets. Each pseudo-CT was created based on an available method of assigning electron density to an anatomic image. An inversely modulated radiotherapy (IMRT) plan was developed on each planning CT. The dose calculation error caused by each pseudo-CT data set was quantified by comparing the dose calculated each pseudo-CT data set with that calculated on the original planning CT for the same IMRT plan. The optimization uncertainty introduced by the dose calculation error was quantified by re-optimizing the same optimization parameters on each pseudo-CT data set and comparing against the original planning CT. Dose differences were quantified by assessing the Equivalent Uniform Dose (EUD) for targets and relevant organs at risk. Across all pseudo-CT data sets and all organs, the absolute mean dose calculation error was 0.2 Gy, and was within 2 % of the prescription dose in 98.5 % of cases. Then absolute mean optimisation error was 0.3 Gy EUD, indicating that that inverse optimisation is impacted by the dose calculation error. However, the additional uncertainty introduced to plan optimisation is small compared the sources of variation which already exist. Use of inaccurate electron density data for inverse treatment planning results in a dose calculation error, which in turn introduces additional uncertainty into the plan optimization process. In this study, we showed that both of these effects are clinically acceptable for cervix cancer patients using four different pseudo-CT data sets. Dose calculation and inverse optimization on pseudo-CT is feasible for this patient cohort.

  20. Effect of intravenous clonidine premedication for the bloodless surgical field in patients undergoing middle ear or nasal surgery: A comparison of three different doses

    PubMed Central

    Ramchandani, Sarita; Lakra, Anand Masih; Shah, Pratibha Jain; Lalwani, Jaya; Sahare, Kamal Kishore

    2015-01-01

    Aim: To evaluate the effect of intravenous (IV) clonidine premedication for the bloodless surgical field in patients undergoing middle ear or nasal surgery comparing three different doses. Subjects and Methods: This prospective randomized, clinical trial was performed on 90 normotensive patients belonging to American Society of Anesthesiologists grade I/II, aged 18–60 years, of either sex, undergoing routine middle ear or nasal surgery. These patients were divided into three Groups A, B, and C with 30 patients in each according to the dose of IV clonidine used as premedicant that is 3, 4, and 5 µg/kg, respectively. The hypotensive period commenced 10 min after the start of surgery till the surgeon's request for no hypotension required any longer. The target mean blood pressure for producing bloodless surgical field was 60–70 mmHg. During the hypotensive period, the surgeons were asked to rate the bleeding severity score on a six-point scale from 0 (no bleeding) to 5 (severe bleeding). Statistical Analysis Used: ANOVA, Chi-square test, Z-test, standard deviation and P value. Results: IV clonidine premedication in a dose of 4 and 5 µg/kg reduces bleeding and provides a clear field for surgery. It also reduces the requirement of isoflurane, fentanyl, and metoprolol for controlled hypotension. However, clonidine 5 µg/kg was not more effective than clonidine 4 µg/kg in producing these effects rather was associated with some side effects. Conclusion: IV clonidine premedication in a dose of 4 µg/kg is safe and effective for producing a bloodless surgical field in the middle ear and nasal surgery. PMID:26712981

  1. Absolute Stability And Hyperstability In Hilbert Space

    NASA Technical Reports Server (NTRS)

    Wen, John Ting-Yung

    1989-01-01

    Theorems on stabilities of feedback control systems proved. Paper presents recent developments regarding theorems of absolute stability and hyperstability of feedforward-and-feedback control system. Theorems applied in analysis of nonlinear, adaptive, and robust control. Extended to provide sufficient conditions for stability in system including nonlinear feedback subsystem and linear time-invariant (LTI) feedforward subsystem, state space of which is Hilbert space, and input and output spaces having finite numbers of dimensions. (In case of absolute stability, feedback subsystem memoryless and possibly time varying. For hyperstability, feedback system dynamical system.)

  2. Successful treatment of pyogenic granuloma with injection of absolute ethanol.

    PubMed

    Ichimiya, Makoto; Yoshikawa, Yoshiaki; Hamamoto, Yoshiaki; Muto, Masahiko

    2004-04-01

    Pyogenic granuloma (PG) is a small, almost always solitary, sessile or pedunculated, raspberry-like vegetation of exuberant granulation tissue. Conservative treatment by techniques such as cryosurgery, laser surgery, and electrodesiccation are usually adequate, whereas excisional treatment can often result in noticeable scars. We attempted a different approach using an injection of absolute ethanol in five patients with recurrence due to inadequate cryosurgery. This therapy is less invasive than surgical excision and appears to be an alternative therapy for PG.

  3. [Correction of polyhypovitaminosis in rats, having standard and enriched with polyunsaturated fatty acids family omega-3 diets with different doses of vitamins].

    PubMed

    Beketova, N A; Vrzhesinskaia, O A; Kodentsova, V M; Kosheleva, O V; Preverzeva, O G; Sokol'nikov, A A

    2013-01-01

    The efficiency of the correction of combined alimentary vitamin deficit in male Wistar rats (body weight 90-121 g) fed standard diet or enriched with omega-3 polyunsaturated fatty acids diet (by replacing sunflower oil (4.5% of the diet) with linseed oil) with different doses (physiological and enhanced) of vitamins has been investigated. The control group of animals (n = 12) received a complete semisynthetic diet during all experimental period (42 d). The animals of the test groups (each of 20 rats) received vitamin-deficient diet containing sunflower or linseed oil and 20% per cent of vitamin mixture amount in control diet from which vitamin E had been excluded. After 28 days of such feeding each of test groups was divided into two subgroups (6-8 rats in each), and the next 14 days the animals of subgroups received the diet with different degree of vitamin compensation (50 or 180% percent of vitamin content in the diet of the control group). The addition of both low and high vitamin dose in deficient diet based on standard fat component did not compensate the reduced liver vitamin A content, which amounted to 47.4% of the level in the liver of the control group. The lack of vitamin E in animals was eliminated only after adding of the enhanced dose of vitamin E to the ration. Recovering of decreased plasma and liver B2 level, plasma 25(OH)D and liver vitamin B1 content have been occurred after addition of the low dose of these vitamins to rat diet. Increasing of omega-3 PUFA diet level improved vitamins A and D sufficiency to some extent, but was accompanied by the significant reduction of rat liver alfa-tocopherol content both under combined vitamin deficiency (by 14%) and increased vitamins consumption (by 43%). PUFA enrichment of the diet of rats with vitamin deficiency had no impact on vitamin B1 and B2 liver level. The use of high doses of vitamins for a long time to eliminate a combined deficiency of vitamins has been proved.

  4. Absolute determination of local tropospheric OH concentrations

    NASA Technical Reports Server (NTRS)

    Armerding, Wolfgang; Comes, Franz-Josef

    1994-01-01

    Long path absorption (LPA) according to Lambert Beer's law is a method to determine absolute concentrations of trace gases such as tropospheric OH. We have developed a LPA instrument which is based on a rapid tuning of the light source which is a frequency doubled dye laser. The laser is tuned across two or three OH absorption features around 308 nm with a scanning speed of 0.07 cm(exp -1)/microsecond and a repetition rate of 1.3 kHz. This high scanning speed greatly reduces the fluctuation of the light intensity caused by the atmosphere. To obtain the required high sensitivity the laser output power is additionally made constant and stabilized by an electro-optical modulator. The present sensitivity is of the order of a few times 10(exp 5) OH per cm(exp 3) for an acquisition time of a minute and an absorption path length of only 1200 meters so that a folding of the optical path in a multireflection cell was possible leading to a lateral dimension of the cell of a few meters. This allows local measurements to be made. Tropospheric measurements have been carried out in 1991 resulting in the determination of OH diurnal variation at specific days in late summer. Comparison with model calculations have been made. Interferences are mainly due to SO2 absorption. The problem of OH self generation in the multireflection cell is of minor extent. This could be shown by using different experimental methods. The minimum-maximum signal to noise ratio is about 8 x 10(exp -4) for a single scan. Due to the small size of the absorption cell the realization of an open air laboratory is possible in which by use of an additional UV light source or by additional fluxes of trace gases the chemistry can be changed under controlled conditions allowing kinetic studies of tropospheric photochemistry to be made in open air.

  5. Sensitivity to change in cognitive performance and mood measures of energy and fatigue in response to differing doses of caffeine or breakfast.

    PubMed

    Maridakis, Victor; Herring, Matthew P; O'Connor, Patrick J

    2009-01-01

    This double-blind, placebo-controlled, within-subjects (N = 18) experiment compared the sensitivity to change of cognitive performance and mood measures of mental energy following consumption of either 100 or 200-mg caffeine or a 440-calorie breakfast. Breakfast and 200-mg caffeine improved mood and cognitive performance. The sensitivity to change of the measures did not differ in response to any treatment (all p values > .05). The mood and cognitive measures of mental energy used here have similar sensitivity to detecting change in response to a moderate dose of caffeine and breakfast consumption. PMID:19466633

  6. Son preference in Indian families: absolute versus relative wealth effects.

    PubMed

    Gaudin, Sylvestre

    2011-02-01

    The desire for male children is prevalent in India, where son preference has been shown to affect fertility behavior and intrahousehold allocation of resources. Economic theory predicts less gender discrimination in wealthier households, but demographers and sociologists have argued that wealth can exacerbate bias in the Indian context. I argue that these apparently conflicting theories can be reconciled and simultaneously tested if one considers that they are based on two different notions of wealth: one related to resource constraints (absolute wealth), and the other to notions of local status (relative wealth). Using cross-sectional data from the 1998-1999 and 2005-2006 National Family and Health Surveys, I construct measures of absolute and relative wealth by using principal components analysis. A series of statistical models of son preference is estimated by using multilevel methods. Results consistently show that higher absolute wealth is strongly associated with lower son preference, and the effect is 20%-40% stronger when the household's community-specific wealth score is included in the regression. Coefficients on relative wealth are positive and significant although lower in magnitude. Results are robust to using different samples, alternative groupings of households in local areas, different estimation methods, and alternative dependent variables.

  7. Effect of pineal proteins at different dose level on fluoride-induced changes in plasma biochemicals and blood antioxidants enzymes in rats.

    PubMed

    Bharti, Vijay K; Srivastava, R S

    2011-06-01

    Pineal glands secrets melatonin and various proteins and peptides which has many physiological functions. In keeping with this view, present experiment was conducted to know the effect of buffalo (Bubalus bubalis) pineal proteins (PP) at different dose level on fluoride-induced changes in plasma biochemicals and blood antioxidants enzymes in female rats. For this, we took 30 adult female Wistar rats (133-145 g body weights, BW) and divided into five groups (control, group I; 150 ppm fluoride (F), group II; F+ 50 µg pineal proteins, group III; F+ 100 µg PP, group IV; F+ 200 µg PP, group V). We administered fluoride (150 ppm, drinking water) and F+ pineal proteins at 50, 100, and 200 µg/kg BW, i.p. daily for 21 days. Blood samples were collected at the end of the experiments to estimate plasma glucose, proteins, F, lipid peroxidation (LPO), alkaline phosphatase (ALP), and acetyl cholinesterase (AChE) activity. Red blood cells (RBCs) were separated for analysis of LPO, AChE, catalase (CAT), superoxide dismutase (SOD), reduced glutathione (GSH), glutathione peroxidase (GPx), and glutathione reductase (GR) in different groups of animals. Total plasma glucose and protein level did not significantly change in F-treated rats. Plasma ALP and F level were significantly (p < 0.05) high in group II as compared with control and groups III, IV, and V. Administration of PP at different dose level significantly (p < 0.05) reduced the F concentration and ALP activity. Plasma and RBCs AChE activity was significantly (p < 0.05) reduced in F-treated animals as compared with control rats and significantly (p < 0.05) elevated on exogenous administration of PP (groups III and IV). Plasma and RBCs LPO level was significantly (p < 0.05) high in F-alone-treated rats, and PP caused significant (p < 0.05) reduction of LPO in groups IV and V. However, PP treatment in group IV brought better amelioration of F-induced high LPO than in groups III and V. At no

  8. Absolute Points for Multiple Assignment Problems

    ERIC Educational Resources Information Center

    Adlakha, V.; Kowalski, K.

    2006-01-01

    An algorithm is presented to solve multiple assignment problems in which a cost is incurred only when an assignment is made at a given cell. The proposed method recursively searches for single/group absolute points to identify cells that must be loaded in any optimal solution. Unlike other methods, the first solution is the optimal solution. The…

  9. Absolute partial photoionization cross sections of ozone.

    SciTech Connect

    Berkowitz, J.; Chemistry

    2008-04-01

    Despite the current concerns about ozone, absolute partial photoionization cross sections for this molecule in the vacuum ultraviolet (valence) region have been unavailable. By eclectic re-evaluation of old/new data and plausible assumptions, such cross sections have been assembled to fill this void.

  10. Stimulus Probability Effects in Absolute Identification

    ERIC Educational Resources Information Center

    Kent, Christopher; Lamberts, Koen

    2016-01-01

    This study investigated the effect of stimulus presentation probability on accuracy and response times in an absolute identification task. Three schedules of presentation were used to investigate the interaction between presentation probability and stimulus position within the set. Data from individual participants indicated strong effects of…

  11. Teaching Absolute Value Inequalities to Mature Students

    ERIC Educational Resources Information Center

    Sierpinska, Anna; Bobos, Georgeana; Pruncut, Andreea

    2011-01-01

    This paper gives an account of a teaching experiment on absolute value inequalities, whose aim was to identify characteristics of an approach that would realize the potential of the topic to develop theoretical thinking in students enrolled in prerequisite mathematics courses at a large, urban North American university. The potential is…

  12. Solving Absolute Value Equations Algebraically and Geometrically

    ERIC Educational Resources Information Center

    Shiyuan, Wei

    2005-01-01

    The way in which students can improve their comprehension by understanding the geometrical meaning of algebraic equations or solving algebraic equation geometrically is described. Students can experiment with the conditions of the absolute value equation presented, for an interesting way to form an overall understanding of the concept.

  13. Increasing Capacity: Practice Effects in Absolute Identification

    ERIC Educational Resources Information Center

    Dodds, Pennie; Donkin, Christopher; Brown, Scott D.; Heathcote, Andrew

    2011-01-01

    In most of the long history of the study of absolute identification--since Miller's (1956) seminal article--a severe limit on performance has been observed, and this limit has resisted improvement even by extensive practice. In a startling result, Rouder, Morey, Cowan, and Pfaltz (2004) found substantially improved performance with practice in the…

  14. Absolute Radiometric Calibration Of The Thematic Mapper

    NASA Astrophysics Data System (ADS)

    Slater, P. N.; Biggar, S. F.; Holm, R. G.; Jackson, R. D.; Mao, Y.; Moran, M. S.; Palmer, J. M.; Yuan, B.

    1986-11-01

    The results are presented of five in-flight absolute radiometric calibrations, made in the period July 1984 to November 1985, at White Sands, New Mexico, of the solar reflective bands of the Landsat-5 Thematic Mapper (TM) . The 23 bandcalibrations made on the five dates show a ± 2.8% RMS variation from the mean as a percentage of the mean.

  15. On Relative and Absolute Conviction in Mathematics

    ERIC Educational Resources Information Center

    Weber, Keith; Mejia-Ramos, Juan Pablo

    2015-01-01

    Conviction is a central construct in mathematics education research on justification and proof. In this paper, we claim that it is important to distinguish between absolute conviction and relative conviction. We argue that researchers in mathematics education frequently have not done so and this has lead to researchers making unwarranted claims…

  16. TH-C-BRD-04: Beam Modeling and Validation with Triple and Double Gaussian Dose Kernel for Spot Scanning Proton Beams

    SciTech Connect

    Hirayama, S; Takayanagi, T; Fujii, Y; Fujimoto, R; Fujitaka, S; Umezawa, M; Nagamine, Y; Hosaka, M; Yasui, K; Toshito, T

    2014-06-15

    Purpose: To present the validity of our beam modeling with double and triple Gaussian dose kernels for spot scanning proton beams in Nagoya Proton Therapy Center. This study investigates the conformance between the measurements and calculation results in absolute dose with two types of beam kernel. Methods: A dose kernel is one of the important input data required for the treatment planning software. The dose kernel is the 3D dose distribution of an infinitesimal pencil beam of protons in water and consists of integral depth doses and lateral distributions. We have adopted double and triple Gaussian model as lateral distribution in order to take account of the large angle scattering due to nuclear reaction by fitting simulated inwater lateral dose profile for needle proton beam at various depths. The fitted parameters were interpolated as a function of depth in water and were stored as a separate look-up table for the each beam energy. The process of beam modeling is based on the method of MDACC [X.R.Zhu 2013]. Results: From the comparison results between the absolute doses calculated by double Gaussian model and those measured at the center of SOBP, the difference is increased up to 3.5% in the high-energy region because the large angle scattering due to nuclear reaction is not sufficiently considered at intermediate depths in the double Gaussian model. In case of employing triple Gaussian dose kernels, the measured absolute dose at the center of SOBP agrees with calculation within ±1% regardless of the SOBP width and maximum range. Conclusion: We have demonstrated the beam modeling results of dose distribution employing double and triple Gaussian dose kernel. Treatment planning system with the triple Gaussian dose kernel has been successfully verified and applied to the patient treatment with a spot scanning technique in Nagoya Proton Therapy Center.

  17. Comparative effects of insecticides with different mechanisms of action on Chrysoperla externa (Neuroptera: Chrysopidae): lethal, sublethal and dose-response effects.

    PubMed

    Joao Zotti, Moises; Dionel Grutzmacher, Anderson; Heres Lopes, Isac; Smagghe, Guy

    2013-12-01

    The comprehensive knowledge that the delayed systemic and reproduction side effects can be even more deleterious than acute toxicity, has caused a shift in focus toward sublethal effects assessment on physiology and behavior of beneficial insects. In this study, we assessed the risks posed by some insecticides with different mode of action through lethal and delayed systemic sublethal effects on the pupation, adult emergence, and reproduction of the chrysopid Chrysoperla externa (Hagen, 1861; Neuroptera: Chrysopidae), an important predator in pest biological control. The maximum field recommended dose (MFRD) and twice (2×MFRD) for chlorantraniliprole, tebufenozide, and pyriproxyfen were harmless to C. externa. In contrast, all the tested chitin synthesis inhibitors (CSIs) were highly detrimental to the predator, despite of their lack of acute lethal toxicity. Therefore, the safety assumed by using IGRs toward beneficial insects is not valid for chrysopids. Dose-response data showed that although all CSIs have a similar mechanism of action, the relative extent of toxicity may differ (novaluron > lufenuron > teflubenzuron). For CSIs, the delayed systemic effects became obvious at adult emergence, where the predicted no observable effect dose (NOED) was 1/2 048 of the MFRD for novaluron (0.085 ng/insect), and 1/256 of the MFRD for both lufenuron (0.25 ng/insect) and teflubenzuron (0.6 ng/insect). Finally, this work emphasized the significance of performing toxicity risk assessments with an adequate posttreatment period to avoid underestimating the toxicities of insecticides, as the acute lethal toxicity assays may not provide accurate information regarding the long-range effects of hazardous compounds. PMID:23956013

  18. Age-related differences of Ascaridia galli egg output and worm burden in chickens following a single dose infection.

    PubMed

    Gauly, M; Homann, T; Erhardt, G

    2005-03-10

    Ninety white chickens (Lohmann LSL) were reared under helminth-free conditions and divided into five groups. Four groups were artificially infected with 250 embryonated Ascaridia galli eggs at the age of 6, 12, 18 or 24 weeks. Ten birds were kept as uninfected controls. Six and 10 weeks after infection (p.i.), individual faecal egg counts (FEC) were performed. The birds were slaughtered after the second sampling and their gastrointestinal tracts were examined for the presence of adult A. galli. The FEC increased from the first to the second sampling significantly in all the infected groups. The highest increase was shown in the group infected at 12 weeks of age, whereas the increase in the other groups was relatively moderate. However, the total worm burden and mean FEC at the second sampling were highest (p<0.01) in those birds infected at an age of 12 or 18 weeks. The serum protein and triiodothyronine (T3) levels did not differ significantly (p>0.05) between any of the groups. Thyroxine (T4) was significantly different between the groups infected at 6 and 18 weeks of age (p<0.05), and those at 6 and 24 weeks of age (p<0.01). The thyroid hormone levels correlated significantly with the FEC. Age does not seem to play a major role in resistance to A. galli infections in layers, whereas a bird's hormonal and immune status, related to laying activity, seems to have a significant negative impact on resistance.

  19. Absolute concentration measurements inside a jet plume using video digitization

    NASA Astrophysics Data System (ADS)

    Vauquelin, O.

    An experimental system based on digitized video image analysis is used to measure the local value of the concentration inside a plume. Experiments are carried out in a wind-tunnel for a smoke-seeded turbulent jet plume illuminated with a laser beam. Each test is filmed, subsequently video images are digitized and analysed in order to determine the smoke absolute concentration corresponding to each pixel gray level. This non-intrusive measurement technique is first calibrated and different laws connecting gray level to concentration are established. As a first application, concentration measurements are made inside a turbulent jet plume and compared with measurements conducted using a classic gas analysis method. We finally present and discuss the possibilities offered for the measurements of absolute concentration fluctuations.

  20. Simultaneously improving the sensitivity and absolute accuracy of CPT magnetometer.

    PubMed

    Liang, Shang-Qing; Yang, Guo-Qing; Xu, Yun-Fei; Lin, Qiang; Liu, Zhi-Heng; Chen, Zheng-Xiang

    2014-03-24

    A new method to improve the sensitivity and absolute accuracy simultaneously for coherent population trapping (CPT) magnetometer based on the differential detection method is presented. Two modulated optical beams with orthogonal circular polarizations are applied, in one of which two magnetic resonances are excited simultaneously by modulating a 3.4GHz microwave with Larmor frequency. When a microwave frequency shift is introduced, the difference in the power transmitted through the cell in each beam shows a low noise resonance. The sensitivity of 2pT/Hz @ 10Hz is achieved. Meanwhile, the absolute accuracy of ± 0.5nT within the magnetic field ranging from 20000nT to 100000nT is realized.

  1. Brachiaria ruziziensis Responses to Different Fertilization Doses and to the Attack of Mahanarva spectabilis (Hemiptera: Cercopidae) Nymphs and Adults

    PubMed Central

    Aguiar, Daniela de Melo; Auad, Alexander Machado; Fonseca, Marcy das Graças; Leite, Melissa Vieira

    2014-01-01

    Cropping practices are necessary in order to help reduce the population of pest insect, such as the induction of resistance through fertilization. Therefore, this study aimed to assess alterations on the production and quality of Brachiaria ruziziensis when receiving the fertilization composed by the macronutrients NPK and/or exposed to the attack of Mahanarva spectabilis nymphs and adults. B. ruziziensis plants were fertilized according to the recommendation (R), half of the recommended fertilization (H), or non-fertilization (C). They were also exposed to different M. spectabilis nymph and adult densities. The damage, regrowth, and bromatological components were evaluated. The fertilization treatment promoted a higher M. spectabilis nymph survival on B. ruziziensis; however, it reduced the damage caused by the forage exposed to nymphs and adults of pest insect, and it did not alter the quality of the signal grass. Moreover, the fertilization treatment enabled forage recovery, even when exposed to 5 nymphs or 10 spittlebug adults. PMID:24578645

  2. The effect of differences in data base on the determination of absorbed dose in high-energy photon beams using the American Association of Physicists in Medicine protocol.

    PubMed

    Mijnheer, B J; Chin, L M

    1989-01-01

    Exposure rates were adjusted at the National Institute of Standards and Technology (NIST) on January 1, 1986 to take into account more recent values for some physical parameters, mainly in electron stopping power ratios. Exposure calibration factors for 60Co gamma rays Nx will therefore be lowered by 1.1%. Consequently, absorbed dose determinations in high-energy photon beams will be reduced by the same amount if the values for these physical parameters remain unchanged in the American Association of Physicists in Medicine (AAPM) protocol. If the same data base as used at NIST is applied in the AAPM protocol, then Ngas/Nx values, water-air stopping power ratios, and Pwall values will be different. The overall change in absorbed dose determinations using a consistent set of data will be a reduction of 0.8% for 60Co gamma rays and 1.5% for a 20-MV x-ray beam compared to the values before January 1, 1986. Since the net effect is small when different sets of data are applied, the new NIST exposure calibration factors may be used in combination with the AAPM protocol without significant error.

  3. Dose-dependent mortality of the noble crayfish (Astacus astacus) to different strains of the crayfish plague (Aphanomyces astaci).

    PubMed

    Makkonen, Jenny; Kokko, Harri; Vainikka, Anssi; Kortet, Raine; Jussila, Japo

    2014-01-01

    Several reports of the European crayfish species carrying a latent infection of the crayfish plague (Aphanomyces astaci) have emerged and the discussion has focused especially on the lowered virulence of As-genotypes behind decreased mortality. The aim of this study was to compare the killing rate of different A. astaci strains in controlled infection experiments. Two separate infection experiments with three A. astaci strains (UEFT2B (As), Evira6462/06 (As) and UEF8866-2 (PsI)) were made to compare the noble crayfish populations from the Lake Viitajärvi, Tervo, (Expt I) and the Lake Mikitänjärvi, Hyrynsalmi (Expt II). In the Expt III, the Lake Koivujärvi population noble crayfish were infected with A. astaci strains UEF8866-2 (PsI) and Evira6462/06 (As) using different dosages (1, 10, 100 and 1000sporesml(-1)) of A. astaci zoospores. The results confirmed that PsI-genotype strain is highly virulent and kills all the crayfish within a few days. The tested two As-genotype strains caused the mortalities more slowly, and part of the challenged crayfish survived until the end of the follow-up period. Our results also confirmed the variance of virulence among A. astaci strains within the As-genotype and demonstrated that the mortality is dependent on the number of zoospores used in the infections. It also appeared, that some noble crayfish populations show increased resistance towards the crayfish plague, especially against the As-genotype of A. astaci.

  4. Beam Elements with Trapezoidal Cross Section Deformation Modes Based on the Absolute Nodal Coordinate Formulation

    NASA Astrophysics Data System (ADS)

    Matikainen, Marko K.; Dmitrochenko, Oleg; Mikkola, Aki

    2010-09-01

    In this study, higher order beam elements are developed based on the absolute nodal coordinate formulation. The absolute nodal coordinate formulation is a finite element procedure that was recently proposed for flexible multibody applications. Many different elements based on the absolute nodal coordinate formulation are introduced, but still the beam elements are not able to describe the trapezoidal cross section mode. This leads to the locking phenomena, and therefore, the beam elements based on the absolute nodal coordinate formulation with three dimensional elasticity converge to an inexact solution. In order to avoid the locking phenomena, the trapezoidal cross section deformation mode is included in the beam elements based on the absolute nodal coordinate with additional degrees of freedom. The proper description for the trapezoidal cross section deformation is important for the continuum beam elements based on three-dimensional elasticity where the material model is often based on general continuum mechanics.

  5. Influence of coefficient of variation in determining significant difference of quantitative values obtained from 28-day repeated-dose toxicity studies in rats.

    PubMed

    Kobayashi, Katsumi; Sakuratani, Yuki; Abe, Takemaru; Yamazaki, Kazuko; Nishikawa, Satoshi; Yamada, Jun; Hirose, Akihiko; Kamata, Eiichi; Hayashi, Makoto

    2011-01-01

    In order to understand the influence of coefficient of variation (CV) in determining significant difference of quantitative values of 28-day repeated-dose toxicity studies, we examined 59 parameters of 153 studies conducted in accordance with Chemical Substance Control Law in 12 test facilities. Sex difference was observed in 12 parameters and 10 parameters showed large CV in females. The minimum CV was 0.74% for sodium. CV of electrolytes was comparatively small, whereas enzymes had large CV. Large differences in CV were observed for major parameters among 7-8 test facilities. The changes in CV were grossly classified into 11. Our study revealed that a statistical significant difference is usually detected if there is a difference of 7% in mean values between the groups and the groups have a CV of about 7%. A parameter with a CV as high as 30% may be significantly different, if the difference of the mean between the groups is 30%. It would be ideal to use median value to assess the treatment-related effect, rather than mean, when the CV is very high. We recommend using CV of the body weight as a standard to judge the adverse effect level.

  6. Different doses of supplemental vitamin D maintain interleukin-5 without altering skeletal muscle strength: a randomized, double-blind, placebo-controlled study in vitamin D sufficient adults

    PubMed Central

    2012-01-01

    Background Supplemental vitamin D modulates inflammatory cytokines and skeletal muscle function, but results are inconsistent. It is unknown if these inconsistencies are dependent on the supplemental dose of vitamin D. Therefore, the purpose of this study was to identify the influence of different doses of supplemental vitamin D on inflammatory cytokines and muscular strength in young adults. Methods Men (n = 15) and women (n = 15) received a daily placebo or vitamin D supplement (200 or 4000 IU) for 28-d during the winter. Serum 25-hydroxyvitamin D (25(OH)D), cytokine concentrations and muscular (leg) strength measurements were performed prior to and during supplementation. Statistical significance of data were assessed with a two-way (time, treatment) analysis of variance (ANOVA) with repeated measures, followed by a Tukey's Honestly Significant Difference to test multiple pairwise comparisons. Results Upon enrollment, 63% of the subjects were vitamin D sufficient (serum 25(OH)D ≥ 30 ng/ml). Serum 25(OH)D and interleukin (IL)-5 decreased (P < 0.05) across time in the placebo group. Supplemental vitamin D at 200 IU maintained serum 25(OH)D concentrations and increased IL-5 (P < 0.05). Supplemental vitamin D at 4000 IU increased (P < 0.05) serum 25(OH)D without altering IL-5 concentrations. Although serum 25(OH)D concentrations correlated (P < 0.05) with muscle strength, muscle strength was not changed by supplemental vitamin D. Conclusion In young adults who were vitamin D sufficient prior to supplementation, we conclude that a low-daily dose of supplemental vitamin D prevents serum 25(OH)D and IL-5 concentration decreases, and that muscular strength does not parallel the 25(OH)D increase induced by a high-daily dose of supplemental vitamin D. Considering that IL-5 protects against viruses and bacterial infections, these findings could have a broad physiological importance regarding the ability of vitamin D sufficiency to mediate the immune systems protection

  7. Procyanidins improve some disrupted glucose homoeostatic situations: an analysis of doses and treatments according to different animal models.

    PubMed

    Pinent, Montserrat; Cedó, Lidia; Montagut, Gemma; Blay, Mayte; Ardévol, Anna

    2012-01-01

    This review analyses the potential beneficial effects of procyanidins, the main class of flavonoids, in situations in which glucose homeostasis is disrupted. Because the disruption of glucose homeostasis can occur as a result of various causes, we critically review the effects of procyanidins based on the specific origin of each type of disruption. Where little or no insulin is present (Type I diabetic animals), summarized studies of procyanidin treatment suggest that procyanidins have a short-lived insulin-mimetic effect on the internal targets of the organism, an effect not reproduced in normoglycemic, normoinsulinemic healthy animals. Insulin resistance (usually linked to hyperinsulinemia) poses a very different situation. Preventive studies using fructose-fed models indicate that procyanidins may be useful in preventing the induction of damage and thus in limiting hyperglycemia. But the results of other studies using models such as high-fat diet treated rats or genetically obese animals are controversial. Although the effects on glucose parameters are hazy, it is known that procyanidins target key tissues involved in its homeostasis. Interestingly, all available data suggest that procyanidins are more effective when administered in one acute load than when mixed with food.

  8. Aerobic to anaerobic transition in Biomphalaria glabrata (Say, 1818) infected with different miracidial doses of Echinostoma paraensei (Lie and Basch, 1967) by high-performance liquid chromatography.

    PubMed

    Tunholi, Victor Menezes; Tunholi-Alves, Vinícius Menezes; Lustrino, Danilo; Castro, Rosane N; Sant'Ana, Luiza D'Oliveira; Garcia, Juberlan Silva; Maldonado, Arnaldo; dos Santos, Marcos Antônio José; de Lurdes de Azevedo Rodrigues, Maria; Pinheiro, Jairo

    2013-04-01

    The glucose content in the hemolymph and glycogen content in the digestive gland-gonad complex (DGG) and cephalopedal mass of Biomphalaria glabrata exposed to different parasite doses (5 and 50 miracidia) of Echinostoma paraensei as well as the activity of lactate dehydrogenase were evaluated. HPLC (high-performance liquid chromatography) analyses were also performed to determine the concentrations of four organic acids (oxalic, succinic, pyruvic and lactic) present in the hemolymph of infected and uninfected snails, to better understand the effect of infection on the host's energetic/oxidative metabolism. The snails were dissected 1-4 weeks after infection to collect the hemolymph and separate the tissues. There was alteration in the glycemia of the snails at both parasite doses, with a significant increase of glycemia from of the third week after infection in comparison to the control group. Changes were also observed in the lactate dehydrogenase activity, with increased activity as the infection progressed. In parallel, there was a decrease in the glycogen content in the storage tissues, with a markedly greater reduction in the digestive gland-gonad complex (larval development site) in comparison with the cephalopedal mass. Additionally, the infection by both miracidial doses resulted in an increase of oxalic and lactic acid levels, as well as in a decline of piruvic and succinic acid levels in B. glabrata, thus explaining the reduction of the oxidative decarboxylation rate in the tricarboxylic acid cycle and acceleration of the anaerobic degradation of carbohydrates in the snails, through lactic fermentation, which is essential to ensure energy supply and success of the infection.

  9. Effects of low-power laser irradiation (LPLI) at different wavelengths and doses on oxidative stress and fibrogenesis parameters in an animal model of wound healing.

    PubMed

    Silveira, Paulo Cesar Lock; Silva, Luciano A; Freitas, Tiago P; Latini, Alexandra; Pinho, Ricardo A

    2011-01-01

    Gallium-arsenide (GaAs) and helium-neon (HeNe) lasers are the most commonly used low-energy lasers in physiotherapy for promoting wound healing and pain modulation. The aim of this study was investigate the effect of low-power laser irradiation (LPLI) at different wavelengths and doses on oxidative stress and fibrogenesis parameters in an animal model of wound healing. The animals were randomly divided into five groups (n=6): Controls (skin injured animals without local or systemic treatment), skin injury treated with HeNe 1 J/cm(2) (two seg); skin injury treated with HeNe 3 J/cm(2) (six seg); skin injury treated with GaAs 1 J/cm(2) (three seg); skin injury treated with GaAs 3 J/cm(2) (nine seg). A single circular wound measuring 8 mm in diameter was surgically created on the back of the animal. The rats were irradiated at 2, 12, 24, 48, 72, 96, and 120 h after skin injury. The parameters, namely hydroxyproline content, activities of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), and lipid (TBARS) and protein oxidation (carbonyl groups) measurements were assessed. In addition, wound size regression was also analyzed. The results showed an improvement in the wound healing reflected by the reduction in wound size and increased collagen synthesis. Moreover, a significant reduction in TBARS levels, carbonyl content, and SOD and CAT activities were observed after laser irradiation, particularly with the treatments HeNe laser 1 and 3 J/cm(2) dose and GaAs 3 J/cm(2) dose. The data strongly indicate that LPLI therapy is efficient in accelerating the skin wound healing process after wounding, probably by reducing the inflammatory phase and inducing collagen synthesis.

  10. The effect of dose and type of cloprostenol on the luteolytic response of dairy cattle during the Ovsynch protocol under different oestrous cycle and physiological characteristics.

    PubMed

    Valldecabres-Torres, X; Larrosa-Morales, P; Cuervo-Arango, J

    2013-10-01

    The objective of this study was to characterize the effect of dose and type of cloprostenol (CLO) on the luteolytic response of dairy cattle during the Ovsynch protocol under different oestrus cycle and physiological characteristics. Twelve non-lactating dairy cows and 111 lactating dairy cows were used in three experiments. In Experiment I, cows were synchronized so that they had only a 5.5- to 6-day-old corpus luteum (CL) at the time of the prostaglandin F2α (PGF2α ) treatment of Ovsynch. In Experiment II, cows were synchronized so that they had at least a CL of approximately 14 days old at the time of PGF2α treatment and an accessory CL if they had responded to the first GnRH of Ovsynch. Furthermore, in each experiment, cows received either a standard or a double dose of d-CLO as the luteolytic treatment. In Experiment III, lactating cows were blocked by parity and assigned to one of three luteolytic treatments during Ovsynch: 500 μg d,l-CLO, 150 or 300 μg of d-CLO. In Experiment I, the dose of d-CLO had an effect (p = 0.08) on the percentage of cows with full luteolysis, but not in Experiment II (p > 0.1). More cows in Experiment II had full luteolysis than did cows of Experiment I (87% vs 58%, respectively; p = 0.007). In Experiment III, 87.1%, 84.4% and 86.2% lactating dairy cows had full luteolysis and 37.8%, 36.8% and 36.1% of cows became pregnant after treatment with 500 μg d,l-CLO, 150 or 300 μg of d-CLO, respectively (p > 0.05).

  11. A method to evaluate dose errors introduced by dose mapping processes for mass conserving deformations

    PubMed Central

    Yan, C.; Hugo, G.; Salguero, F. J.; Saleh-Sayah, N.; Weiss, E.; Sleeman, W. C.; Siebers, J. V.

    2012-01-01

    Purpose: To present a method to evaluate the dose mapping error introduced by the dose mapping process. In addition, apply the method to evaluate the dose mapping error introduced by the 4D dose calculation process implemented in a research version of commercial treatment planning system for a patient case. Methods: The average dose accumulated in a finite volume should be unchanged when the dose delivered to one anatomic instance of that volume is mapped to a different anatomic instance—provided that the tissue deformation between the anatomic instances is mass conserving. The average dose to a finite volume on image S is defined as dS¯=es/mS, where eS is the energy deposited in the mass mS contained in the volume. Since mass and energy should be conserved, when dS¯ is mapped to an image R(dS→R¯=dR¯), the mean dose mapping error is defined as Δdm¯=|dR¯-dS¯|=|eR/mR-eS/mS|, where the eR and eS are integral doses (energy deposited), and mR and mS are the masses within the region of interest (ROI) on image R and the corresponding ROI on image S, where R and S are the two anatomic instances from the same patient. Alternatively, application of simple differential propagation yields the differential dose mapping error, Δdd¯=|∂d¯∂e*Δe+∂d¯∂m*Δm|=|(eS-eR)mR-(mS-mR)mR2*eR|=α|dR¯-dS¯| with α=mS/mR. A 4D treatment plan on a ten-phase 4D-CT lung patient is used to demonstrate the dose mapping error evaluations for a patient case, in which the accumulated dose, DR¯=∑S=09dS→R¯, and associated error values (ΔDm¯ and ΔDd¯) are calculated for a uniformly spaced set of ROIs. Results: For the single sample patient dose distribution, the average accumulated differential dose mapping error is 4.3%, the average absolute differential dose mapping error is 10.8%, and the average accumulated mean dose mapping error is 5.0%. Accumulated differential dose mapping errors within the gross tumor volume (GTV) and planning target volume (PTV) are lower, 0

  12. Absolute measurements of nonlinear absorption near LIDT at 193 nm

    NASA Astrophysics Data System (ADS)

    Blaschke, Holger; Ristau, Detlev; Welsch, Eberhard; Apel, Oliver

    2001-04-01

    Previous investigations indicate that oxide coatings exhibit non-linear absorption phenomena below 200 nm. Hereby, absorption data of Al2O3 thin film coatings has been determined absolutely by laser calorimetry (LCA) at 193 nm in the low fluence regime. As an alternative, on the basis of the pulsed surface thermal lens technique (STL), photothermal measurements allow to determine the absorption relatively at fluence levels both in the subdamage fluence range far from the damage onset and close to the LIDT. By combining the two measurement techniques, the absolute determination of linear as well as multiphoton absorption can be achieved also in the vicinity of the laser damage fluences. This is of crucial interest because the initiation of damage onset can be observed immediately. Absolute absorption data of Al2O3 coatings at different laser fluences stating of some mJoule/cm2 will be presented for the wavelength 193 nm. Thus, the correlation between the increase of absorption and the onset of breakdown can be illustrated impressively. The evaluation and discussion of the experimental results are focused on the degree of non-linearity of the investigated absorption behavior of oxide single layers initiating the optical breakdown of UV oxide coatings.

  13. Absolute photoionization cross-section of the propargyl radical

    SciTech Connect

    Savee, John D.; Welz, Oliver; Taatjes, Craig A.; Osborn, David L.; Soorkia, Satchin; Selby, Talitha M.

    2012-04-07

    Using synchrotron-generated vacuum-ultraviolet radiation and multiplexed time-resolved photoionization mass spectrometry we have measured the absolute photoionization cross-section for the propargyl (C{sub 3}H{sub 3}) radical, {sigma}{sub propargyl}{sup ion}(E), relative to the known absolute cross-section of the methyl (CH{sub 3}) radical. We generated a stoichiometric 1:1 ratio of C{sub 3}H{sub 3} : CH{sub 3} from 193 nm photolysis of two different C{sub 4}H{sub 6} isomers (1-butyne and 1,3-butadiene). Photolysis of 1-butyne yielded values of {sigma}{sub propargyl}{sup ion}(10.213 eV)=(26.1{+-}4.2) Mb and {sigma}{sub propargyl}{sup ion}(10.413 eV)=(23.4{+-}3.2) Mb, whereas photolysis of 1,3-butadiene yielded values of {sigma}{sub propargyl}{sup ion}(10.213 eV)=(23.6{+-}3.6) Mb and {sigma}{sub propargyl}{sup ion}(10.413 eV)=(25.1{+-}3.5) Mb. These measurements place our relative photoionization cross-section spectrum for propargyl on an absolute scale between 8.6 and 10.5 eV. The cross-section derived from our results is approximately a factor of three larger than previous determinations.

  14. Cardiorespiratory and antinociceptive effects of two different doses of lidocaine administered to horses during a constant intravenous infusion of xylazine and ketamine

    PubMed Central

    2013-01-01

    Background This study investigated the antinociceptive effects of a constant rate infusion (CRI) of lidocaine during xylazine and ketamine anesthesia in horses and aimed to correlate these effects with cardiorespiratory variables, bispectral index (BIS) and plasma lidocaine concentrations. Six adult crossbred mares weighing 320–400 kg were anesthetized on three different occasions. Sedation was performed with xylazine (0.75 mg/kg IV) and anesthetic induction with guaifenesin (75 mg/kg IV) and ketamine (2 mg/kg IV). Anesthesia was maintained with 37.5 μg/kg/min of xylazine and 87.5 μg/kg/min of ketamine both administered intravenously for 75 min. The three treatments consisted of: lidocaine (loading dose: 5 mg/kg, CRI: 100 μg/kg/min; THL); lidocaine (loading dose: 2.5 mg/kg; CRI: 50 μg/kg/min: TLL); and saline (TS); all given 15 min after induction and maintained for 1 h. Antinociception was measured by response to electrical stimulation and bispectral index (BIS) was recorded during anesthesia. Parametric and non-parametric data were compared using ANOVA followed by Student-Newman-Keuls and Friedman tests, respectively. Results Plasma lidocaine concentrations peaked at the end of lidocaine loading dose and was greater in THL (9.61 ± 2.75 μg/mL) vs TLL (4.50 ± 3.34 μg/mL). Electrical noxious stimulation caused purposeful movement in all horses from TS, but no response in THL. The BIS was decreased in THL only and was less when compared to the other treatments throughout anesthesia. Blood pressure, PaO2 and PaCO2 increased and heart rate (HR), respiratory rate (RR), pH, total plasma protein and temperature decreased during anesthesia in all treatments. PaCO2 and HR were greater and RR and pH less in THL compared to TLL and TS at 30 min during anesthesia. All recoveries were considered excellent. Time to standing was longer after THL (60 ± 20 min) than following TLL and TS (32 ± 17 and 30 ± 15 min, respectively

  15. Different doses of equine chorionic gonadotropin on ovarian follicular growth and pregnancy rate of suckled Bos taurus beef cows subjected to timed artificial insemination protocol.

    PubMed

    Pessoa, G A; Martini, A P; Carloto, G W; Rodrigues, M C C; Claro Júnior, I; Baruselli, P S; Brauner, C C; Rubin, M I B; Corrêa, M N; Leivas, F G; Sá Filho, M F

    2016-03-15

    This study evaluated the effect of different doses of eCG (control, 300 or 400 IU) administered at progesterone (P4) device removal in suckled Bos taurus beef cows undergoing a timed artificial insemination (TAI) protocol. A total of 966 cows received a P4 insert and 2.0 mg intramuscular estradiol benzoate at the onset of the synchronization. After 9 days, P4 insert was removed, and 12.5 mg of dinoprost tromethamine and 1 mg of estradiol cypionate were administered, followed by TAI 48 hours later. Then, the cows received one of three treatments as follows: control (n = 323), 300 (n = 326), or 400 IU of eCG (n = 317). A subset (n = 435) of cows in anestrus had their ovaries evaluated using ultrasound at the time of P4 removal and at TAI. Data were analyzed by orthogonal contrasts (C): C1 (eCG effect) and C2 (eCG dose effect). Estrous occurrence (control = 53.7%, 300 IU = 70.6%, and 400 IU = 77.0%) and pregnancy per artificial insemination (control = 29.7%, 300 IU = 44.8%, and 400 IU = 47.6%) were improved by eCG treatment (C1; P = 0.0004 and P < 0.0001, respectively). Furthermore, the cows receiving eCG presented larger follicles at TAI (control = 13.5 ± 0.3 mm, 300 IU = 14.0 ± 0.2 mm, and 400 IU = 15.1 ± 0.3 mm; P < 0.0001; C1). However, there was no effect of eCG dose on any response variables studied (C2; P > 0.15). In conclusion, the eCG treatment administered at the time of P4 removal increased the occurrence of estrus, the larger follicles at TAI, and pregnancy per artificial insemination of suckled B taurus beef cows. Despite the greater occurrence of estrus in noncyclic cows receiving 400 IU of eCG, both eCG doses (300 and 400 IU) were equally efficient to improve pregnancy to artificial insemination.

  16. An absolute measure for a key currency

    NASA Astrophysics Data System (ADS)

    Oya, Shunsuke; Aihara, Kazuyuki; Hirata, Yoshito

    It is generally considered that the US dollar and the euro are the key currencies in the world and in Europe, respectively. However, there is no absolute general measure for a key currency. Here, we investigate the 24-hour periodicity of foreign exchange markets using a recurrence plot, and define an absolute measure for a key currency based on the strength of the periodicity. Moreover, we analyze the time evolution of this measure. The results show that the credibility of the US dollar has not decreased significantly since the Lehman shock, when the Lehman Brothers bankrupted and influenced the economic markets, and has increased even relatively better than that of the euro and that of the Japanese yen.

  17. Absolute radiometry and the solar constant

    NASA Technical Reports Server (NTRS)

    Willson, R. C.

    1974-01-01

    A series of active cavity radiometers (ACRs) are described which have been developed as standard detectors for the accurate measurement of irradiance in absolute units. It is noted that the ACR is an electrical substitution calorimeter, is designed for automatic remote operation in any environment, and can make irradiance measurements in the range from low-level IR fluxes up to 30 solar constants with small absolute uncertainty. The instrument operates in a differential mode by chopping the radiant flux to be measured at a slow rate, and irradiance is determined from two electrical power measurements together with the instrumental constant. Results are reported for measurements of the solar constant with two types of ACRs. The more accurate measurement yielded a value of 136.6 plus or minus 0.7 mW/sq cm (1.958 plus or minus 0.010 cal/sq cm per min).

  18. From Hubble's NGSL to Absolute Fluxes

    NASA Technical Reports Server (NTRS)

    Heap, Sara R.; Lindler, Don

    2012-01-01

    Hubble's Next Generation Spectral Library (NGSL) consists of R-l000 spectra of 374 stars of assorted temperature, gravity, and metallicity. Each spectrum covers the wavelength range, 0.18-1.00 microns. The library can be viewed and/or downloaded from the website, http://archive.stsci.edu/prepds/stisngsll. Stars in the NGSL are now being used as absolute flux standards at ground-based observatories. However, the uncertainty in the absolute flux is about 2%, which does not meet the requirements of dark-energy surveys. We are therefore developing an observing procedure that should yield fluxes with uncertainties less than 1 % and will take part in an HST proposal to observe up to 15 stars using this new procedure.

  19. Impact of Winko on absolute discharges.

    PubMed

    Balachandra, Krishna; Swaminath, Sam; Litman, Larry C

    2004-01-01

    In Canada, case laws have had a significant impact on the way mentally ill offenders are managed, both in the criminal justice system and in the forensic mental health system. The Supreme Court of Canada's decision with respect to Winko has set a major precedent in the application of the test of significant risk to the safety of the public in making dispositions by the Ontario Review Board and granting absolute discharges to the mentally ill offenders in the forensic health system. Our study examines the impact of the Supreme Court of Canada's decision before and after Winko. The results show that the numbers of absolute discharges have increased post-Winko, which was statistically significant, but there could be other factors influencing this increase.

  20. Asteroid absolute magnitudes and slope parameters

    NASA Technical Reports Server (NTRS)

    Tedesco, Edward F.

    1991-01-01

    A new listing of absolute magnitudes (H) and slope parameters (G) has been created and published in the Minor Planet Circulars; this same listing will appear in the 1992 Ephemerides of Minor Planets. Unlike previous listings, the values of the current list were derived from fits of data at the V band. All observations were reduced in the same fashion using, where appropriate, a single basis default value of 0.15 for the slope parameter. Distances and phase angles were computed for each observation. The data for 113 asteroids was of sufficiently high quality to permit derivation of their H and G. These improved absolute magnitudes and slope parameters will be used to deduce the most reliable bias-corrected asteroid size-frequency distribution yet made.

  1. Absolute-magnitude distributions of supernovae

    SciTech Connect

    Richardson, Dean; Wright, John; Jenkins III, Robert L.; Maddox, Larry

    2014-05-01

    The absolute-magnitude distributions of seven supernova (SN) types are presented. The data used here were primarily taken from the Asiago Supernova Catalogue, but were supplemented with additional data. We accounted for both foreground and host-galaxy extinction. A bootstrap method is used to correct the samples for Malmquist bias. Separately, we generate volume-limited samples, restricted to events within 100 Mpc. We find that the superluminous events (M{sub B} < –21) make up only about 0.1% of all SNe in the bias-corrected sample. The subluminous events (M{sub B} > –15) make up about 3%. The normal Ia distribution was the brightest with a mean absolute blue magnitude of –19.25. The IIP distribution was the dimmest at –16.75.

  2. Similar Comparative Low and High Doses of Deltamethrin and Acetamiprid Differently Impair the Retrieval of the Proboscis Extension Reflex in the Forager Honey Bee (Apis mellifera).

    PubMed

    Thany, Steeve H; Bourdin, Céline M; Graton, Jérôme; Laurent, Adèle D; Mathé-Allainmat, Monique; Lebreton, Jacques; Questel, Jean-Yves le

    2015-01-01

    In the present study, the effects of low (10 ng/bee) and high (100 ng/bee) doses of acetamiprid and deltamethrin insecticides on multi-trial learning and retrieval were evaluated in the honey bee Apis mellifera. After oral application, acetamiprid and deltamethrin at the concentrations used were not able to impair learning sessions. When the retention tests were performed 1 h, 6 h, and 24 h after learning, we found a significant difference between bees after learning sessions when drugs were applied 24 h before learning. Deltamethrin-treated bees were found to be more sensitive at 10 ng/bee and 100 ng/bee doses compared to acetamiprid-treated bees, only with amounts of 100 ng/bee and at 6 h and 24 h delays. When insecticides were applied during learning sessions, none of the tested insecticides was able to impair learning performance at 10 ng/bee or 100 ng/bee but retention performance was altered 24 h after learning sessions. Acetamiprid was the only one to impair retrieval at 10 ng/bee, whereas at 100 ng/bee an impairment of retrieval was found with both insecticides. The present results therefore suggest that acetamiprid and deltamethrin are able to impair retrieval performance in the honey bee Apis mellifera. PMID:26466901

  3. Similar Comparative Low and High Doses of Deltamethrin and Acetamiprid Differently Impair the Retrieval of the Proboscis Extension Reflex in the Forager Honey Bee (Apis mellifera)

    PubMed Central

    Thany, Steeve H.; Bourdin, Céline M.; Graton, Jérôme; Laurent, Adèle D.; Mathé-Allainmat, Monique; Lebreton, Jacques; Le Questel, Jean-Yves

    2015-01-01

    In the present study, the effects of low (10 ng/bee) and high (100 ng/bee) doses of acetamiprid and deltamethrin insecticides on multi-trial learning and retrieval were evaluated in the honey bee Apis mellifera. After oral application, acetamiprid and deltamethrin at the concentrations used were not able to impair learning sessions. When the retention tests were performed 1 h, 6 h, and 24 h after learning, we found a significant difference between bees after learning sessions when drugs were applied 24 h before learning. Deltamethrin-treated bees were found to be more sensitive at 10 ng/bee and 100 ng/bee doses compared to acetamiprid-treated bees, only with amounts of 100 ng/bee and at 6 h and 24 h delays. When insecticides were applied during learning sessions, none of the tested insecticides was able to impair learning performance at 10 ng/bee or 100 ng/bee but retention performance was altered 24 h after learning sessions. Acetamiprid was the only one to impair retrieval at 10 ng/bee, whereas at 100 ng/bee an impairment of retrieval was found with both insecticides. The present results therefore suggest that acetamiprid and deltamethrin are able to impair retrieval performance in the honey bee Apis mellifera. PMID:26466901

  4. Absolute GNSS Antenna Calibration at the National Geodetic Survey

    NASA Astrophysics Data System (ADS)

    Mader, G.; Bilich, A.; Geoghegan, C.

    2012-04-01

    Geodetic GNSS applications routinely demand millimeter precision and extremely high levels of accuracy. To achieve these accuracies, measurement and instrument biases at the centimeter to millimeter level must be understood. One of these biases is the antenna phase center, the apparent point of signal reception for a GNSS antenna. It has been well established that phase center patterns differ between antenna models and manufacturers; additional research suggests that the addition of a radome or the choice of antenna mount can significantly alter those a priori phase center patterns. For the more demanding GNSS positioning applications and especially in cases of mixed-antenna networks, it is all the more important to know antenna phase center variations as a function of both elevation and azimuth in the antenna reference frame and incorporate these models into analysis software. To help meet the needs of the high-precision GNSS community, the National Geodetic Survey (NGS) now operates an absolute antenna calibration facility. Located in Corbin, Virginia, this facility uses field measurements and actual GNSS satellite signals to quantitatively determine the carrier phase advance/delay introduced by the antenna element. The NGS facility was built to serve traditional NGS constituents such as the surveying and geodesy communities, however calibration services are open and available to all GNSS users as the calibration schedule permits. All phase center patterns computed by this facility will be publicly available and disseminated in both the ANTEX and NGS formats. We describe the NGS calibration facility, and discuss the observation models and strategy currently used to generate NGS absolute calibrations. We demonstrate that NGS absolute phase center variation (PCV) patterns are consistent with published values determined by other absolute antenna calibration facilities, and outline future planned refinements to the system.

  5. Absolute photoionization cross sections of atomic oxygen

    NASA Technical Reports Server (NTRS)

    Samson, J. A. R.; Pareek, P. N.

    1985-01-01

    The absolute values of photoionization cross sections of atomic oxygen were measured from the ionization threshold to 120 A. An auto-ionizing resonance belonging to the 2S2P4(4P)3P(3Do, 3So) transition was observed at 479.43 A and another line at 389.97 A. The experimental data is in excellent agreement with rigorous close-coupling calculations that include electron correlations in both the initial and final states.

  6. Absolute photoionization cross sections of atomic oxygen

    NASA Technical Reports Server (NTRS)

    Samson, J. A. R.; Pareek, P. N.

    1982-01-01

    The absolute values of photoionization cross sections of atomic oxygen were measured from the ionization threshold to 120 A. An auto-ionizing resonance belonging to the 2S2P4(4P)3P(3Do, 3So)