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Sample records for absorbed fraction internal irradiation

  1. Specific absorbed fraction for Korean adult voxel phantom from internal photon source.

    PubMed

    Lee, C; Park, S; Lee, J K

    2007-01-01

    Absorbed fraction (AF) and specific absorbed fraction (SAF) are crucial values for the calculation of radionuclide S-values and consequently for internal dose estimates. The formalism of the Medical Internal Radiation Dose (MIRD) committee of the Society of Nuclear Medicine (SNM) has been utilised as a standard in the calculation of individual organ doses for biologically distributed radionuclides and for different types of radiation. Although those quantities are highly sensitive to individual anatomical difference, the SAF dataset calculated by Caucasian-based stylised phantoms have been applied to Korean population until now. This study was intended to calculate the SAFs by using realistic Korean voxel phantom and Monte Carlo transport technique for the first time and compare the results with those of the existing Caucasian-based data and the Korean stylised phantom published recently. The up-to-date realistic Korean voxel phantom, KTMAN-2, which was developed from computed tomography (CT) images of an average Korean adult male, was employed for Monte Carlo calculation using EGSnrc user-code, developed for the purpose of this study. The SAFs for 32 target organs and tissues from the photon source, uniformly deposited in a total of 37 source organs and tissues, were calculated from KTMAN-2. The results were compared with those for an adult phantom of Oak Ridge National Laboratory (ORNL) and Korean adult stylised phantom. Two major reasons of discrepancy were analysed: (1) racial difference between the Korean and the Caucasian and (2) anatomical difference between stylised and voxel phantoms. When the source organ was identical to the target organ, difference in SAF caused by the difference in target-organ mass between the Korean and the Caucasian phantoms was mainly observed. When the source and target organs were not identical, significant difference in SAF was observed which was mainly attributed to the difference in inter-organ distance and organ shape between

  2. Specific absorbed fractions of energy at various ages from internal photon sources: 6, Newborn

    SciTech Connect

    Cristy, M.; Eckerman, K.F.

    1987-04-01

    Specific absorbed fraction (PHI's) in various organs of the body (target organs) from sources of monoenergetic photons in various other organs (source organs) are tabulated. In this volume PHI-values are tabulated for a newborn or 3.4-kg person. These PHI-values can be used in calculating the photon component of the dose-equivalent rate in a given target from a given radionuclide that is present in a given source organ. The International Commission on Radiological Protection recognizes that the endosteal, or bone surface, cells are the tissue at risk for bone cancer. We have applied the dosimetry methods that Spiers and co-workers developed for beta-emitting radionuclides deposited in bone to follow the transport of secondary electrons that were freed by photon interactions through the microscopic structure of the skeleton. With these methods we can estimate PHI in the endosteal cells and can better estimate PHI in the active marrow; the latter is overestimated with other methods at photon energies below 200 keV. 12 refs., 2 tabs.

  3. Specific absorbed fractions of energy from internal photon sources in brain tumor and cerebrospinal fluid

    SciTech Connect

    Evans, J.F. )); Stubbs, J.B. )

    1995-03-01

    Transferrin, radiolabeled with In-111, can be coinjected into glioblastoma multiforme lesions, and subsequent scintigraphic imaging can demonstrate the biokinetics of the cytotoxic transferrin. The administration of [sup 111]In transferrin into a brain tumor results in distribution of radioactivity in the brain, brain tumor, and the cerebrospinal fluid (CSF). Information about absorbed radiation doses to these regions, as well as other nearby tissues and organs, is important for evaluating radiation-related risks from this procedure. The radiation dose is usually estimated for a mathematical representation of the human body. We have included source/target regions for the eye, lens of the eye, spinal column, spinal CSF, cranial CSF, and a 100-g tumor within the brain of an adult male phantom developed by Cristy and Eckerman. The spinal column, spinal CSF, and the eyes have not been routinely included in photon transport simulations. Specific absorbed fractions (SAFs) as a function of photon energy were calculated using the ALGAMP computer code, which utilizes Monte Carlo techniques for simulating photon transport. The ALGAMP code was run three times, with the source activity distributed uniformly within the tumor, cranial CSF, and the spinal CSF volumes. These SAFs, which were generated for 12 discrete photon energies ranging from 0.01 to 4.0 MeV, were used with decay scheme data to calculate [ital S]-values needed for estimating absorbed doses. [ital S]-values for [sup 111]In are given for three source regions (brain tumor, cranial CSF, and spinal CSF) and all standard target regions/organs, the eye and lens, as well as to tissues within these source regions. [ital S]-values for the skeletal regions containing active marrow are estimated. These results are useful in evaluating the radiation doses from intracranial administration of [sup 111]In transferrin.

  4. Internal photomechanical fracture of spatially limited absorbers irradiated by short laser pulses

    NASA Astrophysics Data System (ADS)

    Paltauf, Guenther; Schmidt-Kloiber, Heinz

    1998-05-01

    A photomechanical damage mechanism in abosrbing regions or particles surrounded by a non-abosrbing medium after irradiation with a short laser pulse is investigated experimentally and theoretically. In tissue, such absorbers are for example melanosomes, blood vessels or tatoo pigments. It follows from theoretical considerations that the photoacoustic wave caused by irradiation of a spatially limited volume contains both compressive and tensile stress. Experiments were performed to test whether these tensile stresses cause cavitation in absorbers of spherical or cylindrical shape. High-speed video images of liquid spheres or gelatin cylinders (diameters 200 to 300 micrometer) suspended in oil showed that cavitation occurs at the center of the spheres or on the cylinder axis, respectively, shortly after irradiation with a light pulse (6 ns duration) from an optical parametric oscillator. The cavitation effect was observed at maximum temperatures below and above the boiling point and at ratios of the absorber size on the absorption length larger and smaller than one. The experimental findings are supported by theoretical calculations, from which strong tensile stresses are predicted in the interior of the absorbers, even if the values of acoustic impedance inside and outside the absorbing volume are equal. The reported effect is believed to cause damage to absorbers if the pulse duration is short enough to provide stress confinement, that is if the time an acoustic wave needs to cross the abosrbing region is longer than the pulse duration. For small absorbers such as melanosomes with a size of about 1 micrometer this requires a laser pulse duration in the picosecond regime.

  5. Internal absorber solar collector

    DOEpatents

    Sletten, Carlyle J.; Herskovitz, Sheldon B.; Holt, F. S.; Sletten, E. J.

    1981-01-01

    Thin solar collecting panels are described made from arrays of small rod collectors consisting of a refracting dielectric rod lens with an absorber imbedded within it and a reflecting mirror coated on the back side of the dielectric rod. Non-tracking collector panels on vertical walls or roof tops receive approximately 90% of solar radiation within an acceptance zone 60.degree. in elevation angle by 120.degree. or more in the azimuth sectors with a collector concentration ratio of approximately 3.0. Miniaturized construction of the circular dielectric rods with internal absorbers reduces the weight per area of glass, plastic and metal used in the collector panels. No external parts or insulation are needed as heat losses are low due to partial vacuum or low conductivity gas surrounding heated portions of the collector. The miniature internal absorbers are generally made of solid copper with black selective surface and the collected solar heat is extracted at the collector ends by thermal conductivity along the absorber rods. Heat is removed from end fittings by use of liquid circulants. Several alternate constructions are provided for simplifying collector panel fabrication and for preventing the thermal expansion and contraction of the heated absorber or circulant tubes from damaging vacuum seals. In a modified version of the internal absorber collector, oil with temperature dependent viscosity is pumped through a segmented absorber which is now composed of closely spaced insulated metal tubes. In this way the circulant is automatically diverted through heated portions of the absorber giving higher collector concentration ratios than theoretically possible for an unsegmented absorber.

  6. Specific absorbed fractions from the image-based VIP-Man body model and EGS4-VLSI Monte Carlo code: internal electron emitters

    NASA Astrophysics Data System (ADS)

    Chao, T. C.; Xu, X. G.

    2001-04-01

    VIP-Man is a whole-body anatomical model newly developed at Rensselaer from the high-resolution colour images of the National Library of Medicine's Visible Human Project. This paper summarizes the use of VIP-Man and the Monte Carlo method to calculate specific absorbed fractions from internal electron emitters. A specially designed EGS4 user code, named EGS4-VLSI, was developed to use the extremely large number of image data contained in the VIP-Man. Monoenergetic and isotropic electron emitters with energies from 100 keV to 4 MeV are considered to be uniformly distributed in 26 organs. This paper presents, for the first time, results of internal electron exposures based on a realistic whole-body tomographic model. Because VIP-Man has many organs and tissues that were previously not well defined (or not available) in other models, the efforts at Rensselaer and elsewhere bring an unprecedented opportunity to significantly improve the internal dosimetry.

  7. Application of the ICRP/ICRU reference computational phantoms to internal dosimetry: calculation of specific absorbed fractions of energy for photons and electrons.

    PubMed

    Hadid, L; Desbrée, A; Schlattl, H; Franck, D; Blanchardon, E; Zankl, M

    2010-07-01

    The emission of radiation from a contaminated body region is connected with the dose received by radiosensitive tissue through the specific absorbed fractions (SAFs) of emitted energy, which is therefore an essential quantity for internal dose assessment. A set of SAFs were calculated using the new adult reference computational phantoms, released by the International Commission on Radiological Protection (ICRP) together with the International Commission on Radiation Units and Measurements (ICRU). Part of these results has been recently published in ICRP Publication 110 (2009 Adult reference computational phantoms (Oxford: Elsevier)). In this paper, we mainly discuss the results and also present them in numeric form. The emission of monoenergetic photons and electrons with energies ranging from 10 keV to 10 MeV was simulated for three source organs: lungs, thyroid and liver. SAFs were calculated for four target regions in the body: lungs, colon wall, breasts and stomach wall. For quality assurance purposes, the simulations were performed simultaneously at the Helmholtz Zentrum München (HMGU, Germany) and at the Institute for Radiological Protection and Nuclear Safety (IRSN, France), using the Monte Carlo transport codes EGSnrc and MCNPX, respectively. The comparison of results shows overall agreement for photons and high-energy electrons with differences lower than 8%. Nevertheless, significant differences were found for electrons at lower energy for distant source/target organ pairs. Finally, the results for photons were compared to the SAF values derived using mathematical phantoms. Significant variations that can amount to 200% were found. The main reason for these differences is the change of geometry in the more realistic voxel body models. For electrons, no SAFs have been computed with the mathematical phantoms; instead, approximate formulae have been used by both the Medical Internal Radiation Dose committee (MIRD) and the ICRP due to the limitations imposed

  8. Application of the ICRP/ICRU reference computational phantoms to internal dosimetry: calculation of specific absorbed fractions of energy for photons and electrons

    NASA Astrophysics Data System (ADS)

    Hadid, L.; Desbrée, A.; Schlattl, H.; Franck, D.; Blanchardon, E.; Zankl, M.

    2010-07-01

    The emission of radiation from a contaminated body region is connected with the dose received by radiosensitive tissue through the specific absorbed fractions (SAFs) of emitted energy, which is therefore an essential quantity for internal dose assessment. A set of SAFs were calculated using the new adult reference computational phantoms, released by the International Commission on Radiological Protection (ICRP) together with the International Commission on Radiation Units and Measurements (ICRU). Part of these results has been recently published in ICRP Publication 110 (2009 Adult reference computational phantoms (Oxford: Elsevier)). In this paper, we mainly discuss the results and also present them in numeric form. The emission of monoenergetic photons and electrons with energies ranging from 10 keV to 10 MeV was simulated for three source organs: lungs, thyroid and liver. SAFs were calculated for four target regions in the body: lungs, colon wall, breasts and stomach wall. For quality assurance purposes, the simulations were performed simultaneously at the Helmholtz Zentrum München (HMGU, Germany) and at the Institute for Radiological Protection and Nuclear Safety (IRSN, France), using the Monte Carlo transport codes EGSnrc and MCNPX, respectively. The comparison of results shows overall agreement for photons and high-energy electrons with differences lower than 8%. Nevertheless, significant differences were found for electrons at lower energy for distant source/target organ pairs. Finally, the results for photons were compared to the SAF values derived using mathematical phantoms. Significant variations that can amount to 200% were found. The main reason for these differences is the change of geometry in the more realistic voxel body models. For electrons, no SAFs have been computed with the mathematical phantoms; instead, approximate formulae have been used by both the Medical Internal Radiation Dose committee (MIRD) and the ICRP due to the limitations imposed

  9. Comparison of internal doses calculated using the specific absorbed fractions of the average adult Japanese male phantom with those of the reference computational phantom-adult male of ICRP publication 110

    NASA Astrophysics Data System (ADS)

    Manabe, Kentaro; Sato, Kaoru; Endo, Akira

    2014-03-01

    In order to study the effects of body sizes and masses of organs and tissues on internal dose assessment, the values corresponding to effective dose coefficients for intakes of radionuclides were calculated using the specific absorbed fractions (SAFs) of two phantoms: the average adult Japanese male phantom (JM-103) and the reference computational phantom-adult male (RCP-AM) of the International Commission on Radiological Protection. SAFs were evaluated using the phantoms and Monte Carlo radiation transport code MCNPX or were taken from published data. As a result of a comparison for 2894 cases of 923 radionuclides, the maximum discrepancy in the effective dose coefficients between the JM-103 and RCP-AM was about 40%. However, the discrepancies were smaller than 10% in 97% of all cases.

  10. Specific absorbed fractions of electrons and photons for Rad-HUMAN phantom using Monte Carlo method

    NASA Astrophysics Data System (ADS)

    Wang, Wen; Cheng, Meng-Yun; Long, Peng-Cheng; Hu, Li-Qin

    2015-07-01

    The specific absorbed fractions (SAF) for self- and cross-irradiation are effective tools for the internal dose estimation of inhalation and ingestion intakes of radionuclides. A set of SAFs of photons and electrons were calculated using the Rad-HUMAN phantom, which is a computational voxel phantom of a Chinese adult female that was created using the color photographic image of the Chinese Visible Human (CVH) data set by the FDS Team. The model can represent most Chinese adult female anatomical characteristics and can be taken as an individual phantom to investigate the difference of internal dose with Caucasians. In this study, the emission of mono-energetic photons and electrons of 10 keV to 4 MeV energy were calculated using the Monte Carlo particle transport calculation code MCNP. Results were compared with the values from ICRP reference and ORNL models. The results showed that SAF from the Rad-HUMAN have similar trends but are larger than those from the other two models. The differences were due to the racial and anatomical differences in organ mass and inter-organ distance. The SAFs based on the Rad-HUMAN phantom provide an accurate and reliable data for internal radiation dose calculations for Chinese females. Supported by Strategic Priority Research Program of Chinese Academy of Sciences (XDA03040000), National Natural Science Foundation of China (910266004, 11305205, 11305203) and National Special Program for ITER (2014GB112001)

  11. Monte Carlo calculation of specific absorbed fractions: variance reduction techniques

    NASA Astrophysics Data System (ADS)

    Díaz-Londoño, G.; García-Pareja, S.; Salvat, F.; Lallena, A. M.

    2015-04-01

    The purpose of the present work is to calculate specific absorbed fractions using variance reduction techniques and assess the effectiveness of these techniques in improving the efficiency (i.e. reducing the statistical uncertainties) of simulation results in cases where the distance between the source and the target organs is large and/or the target organ is small. The variance reduction techniques of interaction forcing and an ant colony algorithm, which drives the application of splitting and Russian roulette, were applied in Monte Carlo calculations performed with the code penelope for photons with energies from 30 keV to 2 MeV. In the simulations we used a mathematical phantom derived from the well-known MIRD-type adult phantom. The thyroid gland was assumed to be the source organ and urinary bladder, testicles, uterus and ovaries were considered as target organs. Simulations were performed, for each target organ and for photons with different energies, using these variance reduction techniques, all run on the same processor and during a CPU time of 1.5 · 105 s. For energies above 100 keV both interaction forcing and the ant colony method allowed reaching relative uncertainties of the average absorbed dose in the target organs below 4% in all studied cases. When these two techniques were used together, the uncertainty was further reduced, by a factor of 0.5 or less. For photons with energies below 100 keV, an adapted initialization of the ant colony algorithm was required. By using interaction forcing and the ant colony algorithm, realistic values of the specific absorbed fractions can be obtained with relative uncertainties small enough to permit discriminating among simulations performed with different Monte Carlo codes and phantoms. The methodology described in the present work can be employed to calculate specific absorbed fractions for arbitrary arrangements, i.e. energy spectrum of primary radiation, phantom model and source and target organs.

  12. Monte Carlo calculation of specific absorbed fractions: variance reduction techniques.

    PubMed

    Díaz-Londoño, G; García-Pareja, S; Salvat, F; Lallena, A M

    2015-04-01

    The purpose of the present work is to calculate specific absorbed fractions using variance reduction techniques and assess the effectiveness of these techniques in improving the efficiency (i.e. reducing the statistical uncertainties) of simulation results in cases where the distance between the source and the target organs is large and/or the target organ is small. The variance reduction techniques of interaction forcing and an ant colony algorithm, which drives the application of splitting and Russian roulette, were applied in Monte Carlo calculations performed with the code penelope for photons with energies from 30 keV to 2 MeV. In the simulations we used a mathematical phantom derived from the well-known MIRD-type adult phantom. The thyroid gland was assumed to be the source organ and urinary bladder, testicles, uterus and ovaries were considered as target organs. Simulations were performed, for each target organ and for photons with different energies, using these variance reduction techniques, all run on the same processor and during a CPU time of 1.5 · 10(5) s. For energies above 100 keV both interaction forcing and the ant colony method allowed reaching relative uncertainties of the average absorbed dose in the target organs below 4% in all studied cases. When these two techniques were used together, the uncertainty was further reduced, by a factor of 0.5 or less. For photons with energies below 100 keV, an adapted initialization of the ant colony algorithm was required. By using interaction forcing and the ant colony algorithm, realistic values of the specific absorbed fractions can be obtained with relative uncertainties small enough to permit discriminating among simulations performed with different Monte Carlo codes and phantoms. The methodology described in the present work can be employed to calculate specific absorbed fractions for arbitrary arrangements, i.e. energy spectrum of primary radiation, phantom model and source and target organs. PMID

  13. Estimation of dose absorbed fraction for 131I-beta rays in rat thyroid.

    PubMed

    Endo, S; Nitta, Y; Ohtaki, M; Takada, J; Stepanenko, V; Komatsu, K; Tauchi, H; Matsuura, S; Iaskova, E; Hoshi, M

    1998-09-01

    The dose absorbed fraction of rat thyroid by internal deposit of 131I has been calculated as a function of effective diameter of thyroid. The calculations were done using two types of Monte Carlo simulations: one was by a simple energy-loss calculation in spherical volume according to the electron stopping power, and another by a more realistic simulation using Monte Carlo N-Particle Transport code system Version 4A (MCNP). These two calculations were consistent with each other within a deviation of 5%. The absorbed fractions in spherical thyroid were drastically changed up to 5 mm diameter, and then almost all energy was deposited within 10 mm diameter. For the practical application to the animal experiment, the absorbed fractions of ellipsoid-shaped thyroids were also calculated for 1-, 4- and 9-week-old rats, where the fractions were estimated to be 0.61, 0.67 and 0.68, respectively. It was also found that the absorbed fraction of the ellipsoid with various dimensions can be simulated by a calculation for spherical volume with a comparable effective diameter. PMID:9868871

  14. A mathematical model of the nine-month pregnant woman for calculating specific absorbed fractions

    SciTech Connect

    Watson, E.E.; Stabin, M.G.

    1986-01-01

    Existing models that allow calculation of internal doses from radionuclide intakes by both men and women are based on a mathematical model of Reference Man. No attempt has been made to allow for the changing geometric relationships that occur during pregnancy which would affect the doses to the mother's organs and to the fetus. As pregnancy progresses, many of the mother's abdominal organs are repositioned, and their shapes may be somewhat changed. Estimation of specific absorbed fractions requires that existing mathematical models be modified to accommodate these changes. Specific absorbed fractions for Reference Woman at three, six, and nine months of pregnancy should be sufficient for estimating the doses to the pregnant woman and the fetus. This report describes a model for the pregnant woman at nine months. An enlarged uterus was incorporated into a model for Reference Woman. Several abdominal organs as well as the exterior of the trunk were modified to accommodate the new uterus. This model will allow calculation of specific absorbed fractions for the fetus from photon emitters in maternal organs. Specific absorbed fractions for the repositioned maternal organs from other organs can also be calculated. 14 refs., 2 figs.

  15. Fractionated total body irradiation for metastatic neuroblastoma

    SciTech Connect

    Kun, L.E.; Casper, J.T.; Kline, R.W.; Piaskowski, V.D.

    1981-11-01

    Twelve patients over one year old with neuroblastoma (NBL) metastatic to bone and bone marrow entered a study of adjuvant low-dose, fractionated total body irradiation (TBI). Six children who achieved a ''complete clinical response'' following chemotherapy (cyclophosphamide and adriamycin) and surgical resection of the abdominal primary received TBI (10 rad/fraction to totals of 100-120 rad/10-12 fx/12-25 days). Two children received concurrent local irradiation for residual abdominal tumor. The intervals from cessation of chemotherapy to documented progression ranged from 2-16 months, not substatially different from patients receiving similar chemotherapy and surgery without TBI. Three additional children with progressive NBL received similar TBI (80-120 rad/8-12 fx) without objective response.

  16. Photon and electron absorbed fractions calculated from a new tomographic rat model

    NASA Astrophysics Data System (ADS)

    Peixoto, P. H. R.; Vieira, J. W.; Yoriyaz, H.; Lima, F. R. A.

    2008-10-01

    This paper describes the development of a tomographic model of a rat developed using CT images of an adult male Wistar rat for radiation transport studies. It also presents calculations of absorbed fractions (AFs) under internal photon and electron sources using this rat model and the Monte Carlo code MCNP. All data related to the developed phantom were made available for the scientific community as well as the MCNP inputs prepared for AF calculations in that phantom and also all estimated AF values, which could be used to obtain absorbed dose estimates—following the MIRD methodology—in rats similar in size to the presently developed model. Comparison between the rat model developed in this study and that published by Stabin et al (2006 J. Nucl. Med. 47 655) for a 248 g Sprague-Dawley rat, as well as between the estimated AF values for both models, has been presented.

  17. Photon and electron absorbed fractions calculated from a new tomographic rat model.

    PubMed

    Peixoto, P H R; Vieira, J W; Yoriyaz, H; Lima, F R A

    2008-10-01

    This paper describes the development of a tomographic model of a rat developed using CT images of an adult male Wistar rat for radiation transport studies. It also presents calculations of absorbed fractions (AFs) under internal photon and electron sources using this rat model and the Monte Carlo code MCNP. All data related to the developed phantom were made available for the scientific community as well as the MCNP inputs prepared for AF calculations in that phantom and also all estimated AF values, which could be used to obtain absorbed dose estimates--following the MIRD methodology--in rats similar in size to the presently developed model. Comparison between the rat model developed in this study and that published by Stabin et al (2006 J. Nucl. Med. 47 655) for a 248 g Sprague-Dawley rat, as well as between the estimated AF values for both models, has been presented. PMID:18758003

  18. Pterygia: Single-fraction postoperative beta irradiation

    SciTech Connect

    Beyer, D.C. )

    1991-02-01

    A retrospective evaluation was performed with records of 128 patients with 146 eyes that underwent applications of strontium-90 after pterygium excisions performed between 1982 and 1988. With a median follow-up of 13 months, 135 eyes were evaluable. Most pterygia (127 of 135) were treated with a single postoperative application of Sr-90 that delivered 3,000 cGy of beta radiation in one fraction. The actuarial freedom from relapse was 87%; all recurrences occurred within the first 18 months, and 46% of these within the first 3 months. Of the 13 recurrences, 10 have been re-treated with surgery and a second course of beta irradiation with excellent results. All eight eyes for which follow-up was available had no evidence of disease. The ultimate control rate was 96.3% for the series. Correlation of various treatment parameters, including age, bilaterality, prior recurrence, and interval from surgery to irradiation, was performed, and no statistically significant difference was seen. No serious complications have developed. Transient conjunctivitis and photophobia were almost universally seen, with five cases lasting beyond 5 months. The authors conclude that a single application of Sr-90 after surgery is effective and safe in managing pterygia.

  19. Prospects of international trade in irradiated foods

    NASA Astrophysics Data System (ADS)

    Loaharanu, P.

    Irradiation is gaining recognition as a physical process for reducing food losses, enhancing hygienic quality of food and facilitating food trade. At present, 36 countries have approved the use of irradiation for processing collectively over 40 food items either on an unconditional or restricted basis. Commercial use of irradiated foods and food ingredients is being carried out in 22 countries. Technology transfer on food irradiation is being intensified to local industry in different regions. worldwide, a total of 40 commercial/demonstration irradiators available for treating foods have been or are being constructed. Acceptance and control of international trade in irradiated foods were discussed at the International Conference on the Acceptance, Control of and Trade in Irradiated Food, jointly convened by FAO, IAEA, WHO and ITC-UNCTAD/GATT in Geneva, Switzerland, 12-16 December 1988. An "International Document on Food Irradiation" was adopted by consensus at this Conference which will facilitate wider acceptance and control of international trade in irradiated foods.

  20. Experimental demonstration of a transparent graphene millimetre wave absorber with 28% fractional bandwidth at 140 GHz.

    PubMed

    Wu, Bian; Tuncer, Hatice M; Naeem, Majid; Yang, Bin; Cole, Matthew T; Milne, William I; Hao, Yang

    2014-01-01

    The development of transparent radio-frequency electronics has been limited, until recently, by the lack of suitable materials. Naturally thin and transparent graphene may lead to disruptive innovations in such applications. Here, we realize optically transparent broadband absorbers operating in the millimetre wave regime achieved by stacking graphene bearing quartz substrates on a ground plate. Broadband absorption is a result of mutually coupled Fabry-Perot resonators represented by each graphene-quartz substrate. An analytical model has been developed to predict the absorption performance and the angular dependence of the absorber. Using a repeated transfer-and-etch process, multilayer graphene was processed to control its surface resistivity. Millimetre wave reflectometer measurements of the stacked graphene-quartz absorbers demonstrated excellent broadband absorption of 90% with a 28% fractional bandwidth from 125-165 GHz. Our data suggests that the absorbers' operation can also be extended to microwave and low-terahertz bands with negligible loss in performance. PMID:24549254

  1. Experimental demonstration of a transparent graphene millimetre wave absorber with 28% fractional bandwidth at 140 GHz

    PubMed Central

    Wu, Bian; Tuncer, Hatice M.; Naeem, Majid; Yang, Bin; Cole, Matthew T.; Milne, William I.; Hao, Yang

    2014-01-01

    The development of transparent radio-frequency electronics has been limited, until recently, by the lack of suitable materials. Naturally thin and transparent graphene may lead to disruptive innovations in such applications. Here, we realize optically transparent broadband absorbers operating in the millimetre wave regime achieved by stacking graphene bearing quartz substrates on a ground plate. Broadband absorption is a result of mutually coupled Fabry-Perot resonators represented by each graphene-quartz substrate. An analytical model has been developed to predict the absorption performance and the angular dependence of the absorber. Using a repeated transfer-and-etch process, multilayer graphene was processed to control its surface resistivity. Millimetre wave reflectometer measurements of the stacked graphene-quartz absorbers demonstrated excellent broadband absorption of 90% with a 28% fractional bandwidth from 125–165 GHz. Our data suggests that the absorbers' operation can also be extended to microwave and low-terahertz bands with negligible loss in performance. PMID:24549254

  2. Immunosuppression by fractionated total lymphoid irradiation in collagen arthritis

    SciTech Connect

    McCune, W.J.; Buckley, J.A.; Belli, J.A.; Trentham, D.E.

    1982-05-01

    Treatments with fractionated total lymphoid irradiation (TLI) and cyclophosphamide were evaluated for rats injected with type II collagen. Preadministration of TLI and repeated injections of cyclophosphamide suppressed the severity of arthritis and lowered antibody titers to collagen significantly. TLI initiated at the onset of collagen arthritis decreased humoral and cellular responses to collagen but did not affect the severity of arthritis. These data demonstrate that both TLi and cyclophosphamide are immunosuppressive in an experimentally inducible autoimmune disease.

  3. ESR spectroscopy for detecting gamma-irradiated dried vegetables and estimating absorbed doses

    NASA Astrophysics Data System (ADS)

    Kwon, Joong-Ho; Chung, Hyung-Wook; Byun, Myung-Woo

    2000-03-01

    In view of an increasing demand for food irradiation technology, the development of a reliable means of detection for the control of irradiated foods has become necessary. Various vegetable food materials (dried cabbage, carrot, chunggyungchae, garlic, onion, and green onion), which can be legally irradiated in Korea, were subjected to a detection study using ESR spectroscopy. Correlation coefficients ( R2) between absorbed doses (2.5-15 kGy) and their corresponding ESR signals were identified from ESR signals. Pre-established threshold values were successfully applied to the detection of 54 coded unknown samples of dried clean vegetables ( chunggyungchae, Brassica camestris var. chinensis), both non-irradiated and irradiated. The ESR signals of irradiated chunggyungchae decreased over a longer storage time, however, even after 6 months of ambient storage, these signals were still distinguishable from those of non-irradiated samples. The most successful estimates of absorbed dose (5 and 8 kGy) were obtained immediately after irradiation using a quadratic fit with average values of 4.85 and 8.65 kGy being calculated.

  4. New pallet irradiation for Gammaster International

    NASA Astrophysics Data System (ADS)

    Möhlmann, Mr. J. H. F.

    1993-07-01

    State of the art technology offers many opportunities to improve production process with ionizing radiation. Also the requirements to this process become more and more stringent; who was aware of the ISO-9000 Standards? Now it is a necessary concept? Internal and external audits, in particular by Regulatory Bodies such as the FDA and DHSS/MCA, are necessary and commonplace requirements when operating in the Healthcare and Pharmaceutical sectors. Efficiency is a major requirement for industry and also for our radiation business. With all the above mentioned items in mind, Gammaster International B.V. in close cooperation with Nordion International Inc. has developed and built a new type Pallet Irradiator. In this new concept, our 22 years experience in gamma processing and the expertise gained in 10 years of operation of pallet irradiators was incorporated. For this irradiator Gammaster International designed and built a new process control console, incorporating state of the art technology such as: - A well-balanced safety system - A control panel, with status indication for all essential operating and safety parameters - Advances warning for necessary maintenance work - Automatic timer-setting control in addition to an automatic timer setting modification - Clear indication of the position of the product inside the unit and its status - Fully automatic product information generated when the product leaves the irradiation unit - Visual process control with the help of a color monitor - Incremental dose-control - Fault identification

  5. Therapeutic use of fractionated total body and subtotal body irradiation

    SciTech Connect

    Loeffler, R.K.

    1981-05-01

    Ninety-one patients were treated using fractionated subtotal body (STBI) or total body irradiation (TBI). These patients had generalized lymphomas, Hodgkin's disease, leukemias, myelomas, seminomas, or oat-cell carcinomas. Subtotal body irradiation is delivered to the entire body, except for the skull and extremities. It was expected that a significantly higher radiation dose could be administered with STBI than with TBI. STBI was given when there was a reasonable likelihood that malignancy did not involve the shielded volumes. A five- to ten-fold increase in tolerance for STBI was demonstrated. Many of these patients have had long-term (up to 17 year--.permanent) remissions. There is little or no treatment-induced symptomatology, and no sanctuary sites. STBI and TBI are useful therapeutic modalities for many of these malignancies.

  6. SU-D-19A-02: Electron and Photon Absorbed Fractions for Tumors of Varying Sizes and Compositions

    SciTech Connect

    Olguin, E; Bolch, W

    2014-06-01

    Purpose: To calculate absorbed fractions for mono-energetic photons and electrons in tumors of varying compositions using Monte Carlo simulations in MCNPX. Although tumor dosimetry has been previously investigated, these studies are very limited as they only consider absorbed fractions for soft-tissue tumors. Methods: The tumors were modeled as spheres with radii ranging from 0.10 cm to 6.0 cm and with compositions varying from 100% soft tissue to 100% bone. The energies of both the photons and electrons were varied from 10 keV to 10 MeV and were homogenously distributed throughout the tumor volume. Furthermore, this investigation addresses the issue of spherical versus elliptical tumors. Both prolate and oblate spheroid tumors of different compositions were modeled, and absorbed fractions were calculated for various electron and photon energies. Results: The data clearly shows an absorbed fraction dependence on tumor composition. For example, a soft-tissue model for a 3 MeV electron emitted in a 1 cm diameter bone tumor would have an 83% error, and this same assumption for a 500 keV photon would yield a 74% error. Ultimately, empirical fits were created for each of the five material compositions in order to facilitate the absorbed fraction calculation, requiring only the tumor size and particle energy. Furthermore, the data shows that absorbed fractions for moderate spheroids can be well approximated by spherical tumors of equal mass to within 8%, but in the extreme cases where the spheroid resembles more of a disk, the errors can be as high as 30%. Conclusion: This comprehensive data set is most valuable for nuclear medicine dosimetry because it incorporates particle type, particle energy, tumor size, and tumor composition. Although mono-energetic particles were modeled, absorbed fractions and S-values may be calculated for any radionuclide via linear interpolation, as long as the particle energies or spectra are known.

  7. Response functions for computing absorbed dose to skeletal tissues from neutron irradiation.

    PubMed

    Bahadori, Amir A; Johnson, Perry; Jokisch, Derek W; Eckerman, Keith F; Bolch, Wesley E

    2011-11-01

    Spongiosa in the adult human skeleton consists of three tissues-active marrow (AM), inactive marrow (IM) and trabecularized mineral bone (TB). AM is considered to be the target tissue for assessment of both long-term leukemia risk and acute marrow toxicity following radiation exposure. The total shallow marrow (TM(50)), defined as all tissues lying within the first 50 µm of the bone surfaces, is considered to be the radiation target tissue of relevance for radiogenic bone cancer induction. For irradiation by sources external to the body, kerma to homogeneous spongiosa has been used as a surrogate for absorbed dose to both of these tissues, as direct dose calculations are not possible using computational phantoms with homogenized spongiosa. Recent micro-CT imaging of a 40 year old male cadaver has allowed for the accurate modeling of the fine microscopic structure of spongiosa in many regions of the adult skeleton (Hough et al 2011 Phys. Med. Biol. 56 2309-46). This microstructure, along with associated masses and tissue compositions, was used to compute specific absorbed fraction (SAF) values for protons originating in axial and appendicular bone sites (Jokisch et al 2011 Phys. Med. Biol. 56 6857-72). These proton SAFs, bone masses, tissue compositions and proton production cross sections, were subsequently used to construct neutron dose-response functions (DRFs) for both AM and TM(50) targets in each bone of the reference adult male. Kerma conditions were assumed for other resultant charged particles. For comparison, AM, TM(50) and spongiosa kerma coefficients were also calculated. At low incident neutron energies, AM kerma coefficients for neutrons correlate well with values of the AM DRF, while total marrow (TM) kerma coefficients correlate well with values of the TM(50) DRF. At high incident neutron energies, all kerma coefficients and DRFs tend to converge as charged-particle equilibrium is established across the bone site. In the range of 10 eV to 100 Me

  8. Response functions for computing absorbed dose to skeletal tissues from neutron irradiation

    NASA Astrophysics Data System (ADS)

    Bahadori, Amir A.; Johnson, Perry; Jokisch, Derek W.; Eckerman, Keith F.; Bolch, Wesley E.

    2011-11-01

    Spongiosa in the adult human skeleton consists of three tissues—active marrow (AM), inactive marrow (IM) and trabecularized mineral bone (TB). AM is considered to be the target tissue for assessment of both long-term leukemia risk and acute marrow toxicity following radiation exposure. The total shallow marrow (TM50), defined as all tissues lying within the first 50 µm of the bone surfaces, is considered to be the radiation target tissue of relevance for radiogenic bone cancer induction. For irradiation by sources external to the body, kerma to homogeneous spongiosa has been used as a surrogate for absorbed dose to both of these tissues, as direct dose calculations are not possible using computational phantoms with homogenized spongiosa. Recent micro-CT imaging of a 40 year old male cadaver has allowed for the accurate modeling of the fine microscopic structure of spongiosa in many regions of the adult skeleton (Hough et al 2011 Phys. Med. Biol. 56 2309-46). This microstructure, along with associated masses and tissue compositions, was used to compute specific absorbed fraction (SAF) values for protons originating in axial and appendicular bone sites (Jokisch et al 2011 Phys. Med. Biol. 56 6857-72). These proton SAFs, bone masses, tissue compositions and proton production cross sections, were subsequently used to construct neutron dose-response functions (DRFs) for both AM and TM50 targets in each bone of the reference adult male. Kerma conditions were assumed for other resultant charged particles. For comparison, AM, TM50 and spongiosa kerma coefficients were also calculated. At low incident neutron energies, AM kerma coefficients for neutrons correlate well with values of the AM DRF, while total marrow (TM) kerma coefficients correlate well with values of the TM50 DRF. At high incident neutron energies, all kerma coefficients and DRFs tend to converge as charged-particle equilibrium is established across the bone site. In the range of 10 eV to 100 Me

  9. Uneven surface absorbed dose distribution in electron-accelerator irradiation of rubber items

    SciTech Connect

    Gorbunov, I.F.; Pashinin, V.I.; Vanyushkin, B.M.

    1988-02-01

    Electron accelerators for industrial use are equipped with scanning devices, where the scan frequency or linear velocity along the window may vary. In a flow technology, where the items are transported to the irradiation zone at a set rate, the speed of an item may be comparable with the scan speed, so there is substantial nonuniformity in the absorbed dose, which adversely affects the quality. We have examined the dose nonuniformity for long rubber items during vulcanization by means of LUE-8-5RV and ELV-2 accelerators. The absorbed dose is calculated for an elementary part along which the irradiation is uniform on the assumption that current density distribution in the unswept beam is uniform as a result of scattering in the foil.

  10. An international dosimetry exchange for boron neutron capture therapy, Part I: Absorbed dose measurements

    SciTech Connect

    Binns, P.J.; Riley, K.J.; Harling, O.K.

    2005-12-15

    An international collaboration was organized to undertake a dosimetry exchange to enable the future combination of clinical data from different centers conducting neutron capture therapy trials. As a first step (Part I) the dosimetry group from the Americas, represented by MIT, visited the clinical centers at Studsvik (Sweden), VTT Espoo (Finland), and the Nuclear Research Institute (NRI) at Rez (Czech Republic). A combined VTT/NRI group reciprocated with a visit to MIT. Each participant performed a series of dosimetry measurements under equivalent irradiation conditions using methods appropriate to their clinical protocols. This entailed in-air measurements and dose versus depth measurements in a large water phantom. Thermal neutron flux as well as fast neutron and photon absorbed dose rates were measured. Satisfactory agreement in determining absorbed dose within the experimental uncertainties was obtained between the different groups although the measurement uncertainties are large, ranging between 3% and 30% depending upon the dose component and the depth of measurement. To improve the precision in the specification of absorbed dose amongst the participants, the individually measured dose components were normalized to the results from a single method. Assuming a boron concentration of 15 {mu}g g{sup -1} that is typical of concentrations realized clinically with the boron delivery compound boronophenylalanine-fructose, systematic discrepancies in the specification of the total biologically weighted dose of up to 10% were apparent between the different groups. The results from these measurements will be used in future to normalize treatment plan calculations between the different clinical dosimetry protocols as Part II of this study.

  11. An international dosimetry exchange for boron neutron capture therapy. Part I: Absorbed dose measurements.

    PubMed

    Binns, P J; Riley, K J; Harling, O K; Kiger, W S; Munck af Rosenschöld, P M; Giusti, V; Capala, J; Sköld, K; Auterinen, I; Serén, T; Kotiluoto, P; Uusi-Simola, J; Marek, M; Viererbl, L; Spurny, F

    2005-12-01

    An international collaboration was organized to undertake a dosimetry exchange to enable the future combination of clinical data from different centers conducting neutron capture therapy trials. As a first step (Part I) the dosimetry group from the Americas, represented by MIT, visited the clinical centers at Studsvik (Sweden), VTT Espoo (Finland), and the Nuclear Research Institute (NRI) at Rez (Czech Republic). A combined VTT/NRI group reciprocated with a visit to MIT. Each participant performed a series of dosimetry measurements under equivalent irradiation conditions using methods appropriate to their clinical protocols. This entailed in-air measurements and dose versus depth measurements in a large water phantom. Thermal neutron flux as well as fast neutron and photon absorbed dose rates were measured. Satisfactory agreement in determining absorbed dose within the experimental uncertainties was obtained between the different groups although the measurement uncertainties are large, ranging between 3% and 30% depending upon the dose component and the depth of measurement. To improve the precision in the specification of absorbed dose amongst the participants, the individually measured dose components were normalized to the results from a single method. Assuming a boron concentration of 15 microg g(-1) that is typical of concentrations realized clinically with the boron delivery compound boronophenylalanine-fructose, systematic discrepancies in the specification of the total biologically weighted dose of up to 10% were apparent between the different groups. The results from these measurements will be used in future to normalize treatment plan calculations between the different clinical dosimetry protocols as Part II of this study. PMID:16475772

  12. Side branch absorber for exhaust manifold of two-stroke internal combustion engine

    SciTech Connect

    Harris, Ralph E.; Broerman, III, Eugene L.; Bourn, Gary D.

    2011-01-11

    A method of improving scavenging operation of a two-stroke internal combustion engine. The exhaust pressure of the engine is analyzed to determine if there is a pulsation frequency. Acoustic modeling is used to design an absorber. An appropriately designed side branch absorber may be attached to the exhaust manifold.

  13. Mean Absorbed Dose to the Anal-Sphincter Region and Fecal Leakage among Irradiated Prostate Cancer Survivors

    SciTech Connect

    Alsadius, David; Hedelin, Maria; Lundstedt, Dan; Pettersson, Niclas; Wilderaeng, Ulrica; Steineck, Gunnar

    2012-10-01

    Purpose: To supplement previous findings that the absorbed dose of ionizing radiation to the anal sphincter or lower rectum affects the occurrence of fecal leakage among irradiated prostate-cancer survivors. We also wanted to determine whether anatomically defining the anal-sphincter region as the organ at risk could increase the degree of evidence underlying clinical guidelines for restriction doses to eliminate this excess risk. Methods and Materials: We identified 985 men irradiated for prostate cancer between 1993 and 2006. In 2008, we assessed long-term gastrointestinal symptoms among these men using a study-specific questionnaire. We restrict the analysis to the 414 men who had been treated with external beam radiation therapy only (no brachytherapy) to a total dose of 70 Gy in 2-Gy daily fractions to the prostate or postoperative prostatic region. On reconstructed original radiation therapy dose plans, we delineated the anal-sphincter region as an organ at risk. Results: We found that the prevalence of long-term fecal leakage at least once per month was strongly correlated with the mean dose to the anal-sphincter region. Examining different dose intervals, we found a large increase at 40 Gy; {>=}40 Gy compared with <40 Gy gave a prevalence ratio of 3.8 (95% confidence interval 1.6-8.6). Conclusions: This long-term study shows that mean absorbed dose to the anal-sphincter region is associated with the occurrence of long-term fecal leakage among irradiated prostate-cancer survivors; delineating the anal-sphincter region separately from the rectum and applying a restriction of a mean dose <40 Gy will, according to our data, reduce the risk considerably.

  14. Perturbation theory for fractional Brownian motion in presence of absorbing boundaries

    NASA Astrophysics Data System (ADS)

    Wiese, Kay Jörg; Majumdar, Satya N.; Rosso, Alberto

    2011-06-01

    Fractional Brownian motion is a Gaussian process x(t) with zero mean and two-time correlations =D(t12H+t22H-|t1-t2|2H), where H, with 0absorbing boundary at the origin and focus on the probability density P+(x,t) for the process to arrive at x at time t, starting near the origin at time 0, given that it has never crossed the origin. It has a scaling form P+(x,t)~t-HR+(x/tH). Our objective is to compute the scaling function R+(y), which up to now was only known for the Markov case H=1/2. We develop a systematic perturbation theory around this limit, setting H=1/2+ɛ, to calculate the scaling function R+(y) to first order in ɛ. We find that R+(y) behaves as R+(y)~yϕ as y→0 (near the absorbing boundary), while R+(y)~yγexp(-y2/2) as y→∞, with ϕ=1-4ɛ+O(ɛ2) and γ=1-2ɛ+O(ɛ2). Our ɛ-expansion result confirms the scaling relation ϕ=(1-H)/H proposed in Zoia, Rosso, and Majumdar [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.102.120602 102, 120602 (2009)]. We verify our findings via numerical simulations for H=2/3. The tools developed here are versatile, powerful, and adaptable to different situations.

  15. IRRADIATION TESTING OF THE RERTR FUEL MINIPLATES WITH BURNABLE ABSORBERS IN THE ADVANCED TEST REACTOR

    SciTech Connect

    I. Glagolenko; D. Wachs; N. Woolstenhulme; G. Chang; B. Rabin; C. Clark; T. Wiencek

    2010-10-01

    Based on the results of the reactor physics assessment, conversion of the Advanced Test Reactor (ATR) at the Idaho National Laboratory (INL) can be potentially accomplished in two ways, by either using U-10Mo monolithic or U-7Mo dispersion type plates in the ATR fuel element. Both designs, however, would require incorporation of the burnable absorber in several plates of the fuel element to compensate for the excess reactivity and to flatten the radial power profile. Several different types of burnable absorbers were considered initially, but only borated compounds, such as B4C, ZrB2 and Al-B alloys, were selected for testing primarily due to the length of the ATR fuel cycle and fuel manufacturing constraints. To assess and compare irradiation performance of the U-Mo fuels with different burnable absorbers we have designed and manufactured 28 RERTR miniplates (20 fueled and 8 non-fueled) containing fore-mentioned borated compounds. These miniplates will be tested in the ATR as part of the RERTR-13 experiment, which is described in this paper. Detailed plate design, compositions and irradiations conditions are discussed.

  16. The Impact of Atmospheric Aerosols on the Fraction of absorbed Photosynthetically Active Radiation

    NASA Astrophysics Data System (ADS)

    Veroustraete, Frank

    2010-05-01

    Aerosol pollution attracts a growing interest from atmospheric scientists with regard to their impact on health, the global climate and vegetation stress. A hypothesis, less investigated, is whether atmospheric aerosol interactions in the solar radiation field affect the amount of radiation absorbed by vegetation canopies and hence terrestrial vegetation productivity. Typically, aerosols affect vegetation canopy radiation absorption efficiency by altering the physical characteristics of solar radiation incoming on for example a forest canopy. It has been illustrated, that increasing mixing ratio's of atmospheric particulate matter lead to a higher fraction of diffuse sunlight as opposed to direct sunlight. It can be demonstrated, based on the application of atmospheric (MODTRAN) and leaf/canopy radiative transfer (LIBERTY/SPRINT) models, that radiation absorption efficiency in the PAR band of Picea like forests increases with increasing levels of diffuse radiation. It can be documented - on a theoretical basis - as well, that increasing aerosol loads in the atmosphere, induce and increased canopy PAR absorption efficiency. In this paper it is suggested, that atmospheric aerosols have to be taken into account when estimating vegetation gross primary productivity (GPP). The results suggest that Northern hemisphere vegetation CO2 uptake magnitude may increase with increasing atmospheric aerosol loads. Many climate impact scenario's related to vegetation productivity estimates, do not take this phenomenon into account. Boldly speaking, the results suggest a larger sink function for terrestrial vegetation than generally accepted. Keywords: Aerosols, vegetation, fAPAR, CO2 uptake, diffuse radiation.

  17. Marrow toxicity of fractionated vs. single dose total body irradiation is identical in a canine model

    SciTech Connect

    Storb, R.; Raff, R.F.; Graham, T.; Appelbaum, F.R.; Deeg, H.J.; Schuening, F.G.; Shulman, H.; Pepe, M. )

    1993-03-20

    The authors explored in dogs the marrow toxicity of single dose total body irradiation delivered from two opposing [sup 60]Co sources at a rate of 10 cGy/min and compared results to those seen with total body irradiation administered in 100 cGy fractions with minimum interfraction intervals of 6 hr. Dogs were not given marrow transplants. They found that 200 cGy single dose total body irradiation was sublethal, with 12 of 13 dogs showing hematopoietic recovery and survival. Seven of 21 dogs given 300 cGy single dose total body irradiation survived compared to 6 of 10 dogs given 300 cGy fractionated total body irradiation. One of 28 dogs given 400 cGy single dose total body irradiation survived compared to none of six given fractionated radiation. With granulocyte colony stimulating factor (GCSF) administered from day 0-21 after 400 cGy total body irradiation, most dogs survived with hematological recovery. Because of the almost uniform success with GCSF after 400 cGy single dose total body irradiation, a study of GCSF after 400 cGy fractionated total body irradiation was deemed not to be informative and, thus, not carried out. Additional comparisons between single dose and fractionated total body irradiation were carried out with GCSF administered after 500 and 600 cGy of total body irradiation. As with lower doses of total body irradiation, no significant survival differences were seen between the two modes of total body irradiation, and only 3 of 26 dogs studied survived with complete hematological recovery. Overall, therefore, survival among dogs given single dose total body irradiation was not different from that of dogs given fractionated total body irradiation (p = .67). Similarly, the slopes of the postirradiation declines of granulocyte and platelet counts and the rates of their recovery in surviving dogs given equal total doses of single versus fractionated total body irradiation were indistinguishable. 24 refs., 3 figs., 2 tabs.

  18. Uncertainties in electron-absorbed fractions and lung doses from inhaled beta-emitters.

    PubMed

    Farfán, Eduardo B; Bolch, Wesley E; Huston, Thomas E; Rajon, Didier A; Huh, Chulhaeng; Bolch, W Emmett

    2005-01-01

    The computer code LUDUC (Lung Dose Uncertainty Code), developed at the University of Florida, was originally used to investigate the range of potential doses from the inhalation of either plutonium or uranium oxides. The code employs the ICRP Publication 66 Human Respiratory Tract model; however, rather than using simple point estimates for each of the model parameters associated with particle deposition, clearance, and lung-tissue dosimetry, probability density functions are ascribed to these parameters based upon detailed literature review. These distributions are subsequently sampled within LUDUC using Latin hypercube sampling techniques to generate multiple (e.g., approximately 1,000) sets of input vectors (i.e., trials), each yielding a unique estimate of lung dose. In the present study, the dosimetry component of the ICRP-66 model within LUDUC has been extended to explicitly consider variations in the beta particle absorbed fraction due to corresponding uncertainties and biological variabilities in both source and target tissue depths and thicknesses within the bronchi and bronchioles of the thoracic airways. Example dose distributions are given for the inhalation of absorption Type S compounds of 90Sr (Tmax = 546 keV) and 90Y (Tmax = 2,284 keV) as a function of particle size. Over the particle size range of 0.001 to 1 microm, estimates of total lung dose vary by a factor of 10 for 90Sr particles and by a factor of 4 to 10 for 90Y particles. As the particle size increases to 10 microm, dose uncertainties reach a factor of 100 for both radionuclides. In comparisons to identical exposures scenarios run by the LUDEP 2.0 code, Reference Man doses for inhaled beta-emitters were shown to provide slightly conservative estimates of lung dose compared to those in this study where uncertainties in lung airway histology are considered. PMID:15596988

  19. Kantian fractionalization predicts the conflict propensity of the international system

    PubMed Central

    Cranmer, Skyler J.; Menninga, Elizabeth J.; Mucha, Peter J.

    2015-01-01

    Network science has spurred a reexamination of relational phenomena in political science, including the study of international conflict. We introduce a new direction to the study of conflict by showing that the multiplex fractionalization of the international system along three key dimensions is a powerful predictor of the propensity for violent interstate conflict. Even after controlling for well-established conflict indicators, our new measure contributes more to model fit for interstate conflict than all of the previously established measures combined. Moreover, joint democracy plays little, if any, role in predicting system stability, thus challenging perhaps the major empirical finding of the international relations literature. Lastly, the temporal variability of our measure with conflict is consistent with a causal relationship. Our results have real-world policy implications as changes in our fractionalization measure substantially aid the prediction of conflict up to 10 years into the future, allowing it to serve as an early warning sign of international instability. PMID:26338977

  20. Kantian fractionalization predicts the conflict propensity of the international system.

    PubMed

    Cranmer, Skyler J; Menninga, Elizabeth J; Mucha, Peter J

    2015-09-22

    Network science has spurred a reexamination of relational phenomena in political science, including the study of international conflict. We introduce a new direction to the study of conflict by showing that the multiplex fractionalization of the international system along three key dimensions is a powerful predictor of the propensity for violent interstate conflict. Even after controlling for well-established conflict indicators, our new measure contributes more to model fit for interstate conflict than all of the previously established measures combined. Moreover, joint democracy plays little, if any, role in predicting system stability, thus challenging perhaps the major empirical finding of the international relations literature. Lastly, the temporal variability of our measure with conflict is consistent with a causal relationship. Our results have real-world policy implications as changes in our fractionalization measure substantially aid the prediction of conflict up to 10 years into the future, allowing it to serve as an early warning sign of international instability. PMID:26338977

  1. [Estimation of Fraction of Absorbed Photosynthetically Active Radiation for Winter Wheat Based on Hyperspectral Characteristic Parameters].

    PubMed

    Zhang, Chao; Cai, Huan-jie; Li, Zhi-jun

    2015-09-01

    Estimating fraction of absorbed photosynthetically active radiation (FPAR) precisely has great importance for detecting vegetation water content, energy and carbon cycle balance. Based on this, ASD FieldSpec 3 and SunScan canopy analyzer were applied to measure the canopy spectral reflectance and photosynthetically active radiation over whole growth stage of winter wheat. Canopy reflectance spectral data was used to build up 24 hyperspectral characteristic parameters and the correlation between FPAR and different spectral characteristic parameters were analyzed to establish the estimation model of FPAR for winter wheat. The results indicated that there were extremely significant correlations (p<0.01) between FPAR and hyperspectral characteristic parameters except the slope of blue edge (Db). The correlation coefficient between FPAR and the ratio of red edge area to blue edge area (VI4) was the highest, reaching at 0.836. Seven spectral parameters with higher correlation coefficient were selected to establish optimal linear and nonlinear estimation models of FPAR, and the best estimating models of FPAR were obtained by accuracy analysis. For the linear model, the inversin model between green edge and FPAR was the best, with R2, RMSE and RRMSE of predicted model reaching 0.679, 0.111 and 20.82% respectively. For the nonlinear model, the inversion model between VI2 (normalized ratio of green peak to red valley of reflectivity) and FPAR was the best, with R2, RMSE and RRMSE of predicted model reaching 0.724, 0.088 and 21.84% for. In order to further improve the precision of the model, the multiple linear regression and BP neural network methods were used to establish models with multiple high spectral parameters BP neural network model (R2=0.906, RMSE=0.08, RRMSE=16.57%) could significantly improve the inversion precision compared with the single variable model. The results show that using hyperspectral characteristic parameters to estimate FPAR of winter wheat is

  2. A Comparison of Model Calculation and Measurement of Absorbed Dose for Proton Irradiation. Chapter 5

    NASA Technical Reports Server (NTRS)

    Zapp, N.; Semones, E.; Saganti, P.; Cucinotta, F.

    2003-01-01

    With the increase in the amount of time spent EVA that is necessary to complete the construction and subsequent maintenance of ISS, it will become increasingly important for ground support personnel to accurately characterize the radiation exposures incurred by EVA crewmembers. Since exposure measurements cannot be taken within the organs of interest, it is necessary to estimate these exposures by calculation. To validate the methods and tools used to develop these estimates, it is necessary to model experiments performed in a controlled environment. This work is such an effort. A human phantom was outfitted with detector equipment and then placed in American EMU and Orlan-M EVA space suits. The suited phantom was irradiated at the LLUPTF with proton beams of known energies. Absorbed dose measurements were made by the spaceflight operational dosimetrist from JSC at multiple sites in the skin, eye, brain, stomach, and small intestine locations in the phantom. These exposures are then modeled using the BRYNTRN radiation transport code developed at the NASA Langley Research Center, and the CAM (computerized anatomical male) human geometry model of Billings and Yucker. Comparisons of absorbed dose calculations with measurements show excellent agreement. This suggests that there is reason to be confident in the ability of both the transport code and the human body model to estimate proton exposure in ground-based laboratory experiments.

  3. A Model for Assessing Cognitive Impairment after Fractionated Whole-Brain Irradiation in Nonhuman Primates

    PubMed Central

    Robbins, Mike E.; Bourland, J. Daniel; Cline, J. Mark; Wheeler, Kenneth T.; Deadwyler, Sam A.

    2013-01-01

    To investigate the effect of fractionated whole-brain irradiation on nonhuman primates, 6–9-year-old male rhesus monkeys were irradiated with 40 Gy delivered as two 5-Gy fractions/week for 4 weeks. Cognitive function was assessed 5 days/week for 4 months prior to fractionated whole-brain irradiation and for 11 months after irradiation using a Delayed-Match-to-Sample (DMS) task at both low and high cognitive loads. Local rates of cerebral glucose metabolism were measured prior to and 9 months after irradiation using [18F]-2-deoxy-2-fluoro-D-glucose positron emission tomography. Low cognitive load trials did not reveal a significant reduction in performance until 7 months after irradiation; performance then declined progressively. In high cognitive load trials, the initial impairment was observed ~1 month after irradiation. This was followed by a transient recovery period over the next 1–2 months, after which performance declined progressively through 11 months after irradiation. Nine months after irradiation, glucose uptake during the DMS task was decreased in the cuneate and prefrontal cortex and was increased in the cerebellum and thalamus compared with the levels prior to irradiation. Results from this pilot study suggest that the radiation-induced changes in cognition and brain metabolism observed in rhesus monkeys may be similar to those observed in brain tumor patients receiving brain irradiation. PMID:21275607

  4. A model for assessing cognitive impairment after fractionated whole-brain irradiation in nonhuman primates.

    PubMed

    Robbins, Mike E; Bourland, J Daniel; Cline, J Mark; Wheeler, Kenneth T; Deadwyler, Sam A

    2011-04-01

    To investigate the effect of fractionated whole-brain irradiation on nonhuman primates, 6-9-year-old male rhesus monkeys were irradiated with 40 Gy delivered as two 5-Gy fractions/week for 4 weeks. Cognitive function was assessed 5 days/week for 4 months prior to fractionated whole-brain irradiation and for 11 months after irradiation using a Delayed-Match-to-Sample (DMS) task at both low and high cognitive loads. Local rates of cerebral glucose metabolism were measured prior to and 9 months after irradiation using [(18)F]-2-deoxy-2-fluoro-d-glucose positron emission tomography. Low cognitive load trials did not reveal a significant reduction in performance until 7 months after irradiation; performance then declined progressively. In high cognitive load trials, the initial impairment was observed ∼1 month after irradiation. This was followed by a transient recovery period over the next 1-2 months, after which performance declined progressively through 11 months after irradiation. Nine months after irradiation, glucose uptake during the DMS task was decreased in the cuneate and prefrontal cortex and was increased in the cerebellum and thalamus compared with the levels prior to irradiation. Results from this pilot study suggest that the radiation-induced changes in cognition and brain metabolism observed in rhesus monkeys may be similar to those observed in brain tumor patients receiving brain irradiation. PMID:21275607

  5. Study of the spatial distribution of the absorbed dose in blood volumes irradiated using a teletherapy unit

    NASA Astrophysics Data System (ADS)

    Góes, E. G.; Nicolucci, P.; Nali, I. C.; Pelá, C. A.; Bruço, J. L.; Borges, J. C.; Covas, D. T.

    2010-06-01

    Blood irradiation can be performed using a dedicated blood irradiator or a teletherapy unit. A thermal device providing appropriate storage conditions during blood components irradiation with a teletherapy unit has been recently proposed. However, the most appropriated volume of the thermal device was not indicated. The goal of this study was to indicate the most appropriated blood volume for irradiation using a teletherapy unit in order to minimize both the dose heterogeneity in the volume and the blood irradiation time using these equipments. Theoretical and experimental methods were used to study the dose distribution in the blood volume irradiated using a linear accelerator and a cobalt-60 therapy machine. The calculation of absorbed doses in the middle plane of cylindrical acrylic volumes was accomplished by a treatment planning system. Experimentally, we also used cylindrical acrylic phantoms and thermoluminescent dosimeters to confirm the calculated doses. The data obtained were represented by isodose curves. We observed that an irradiation volume should have a height of 28 cm and a diameter of 28 cm and a height of 35 cm and a diameter of 35 cm, when the irradiation is to be performed by a linear accelerator and a cobalt-60 teletherapy unit, respectively. Calculated values of relative doses varied from 93% to 100% in the smaller volume, and from 66% to 100% in the largest one. A difference of 5.0%, approximately, was observed between calculated and experimental data. The size of these volumes permits the irradiation of blood bags in only one bath without compromising the homogeneity of the absorbed dose over the irradiated volume. Thus, these irradiation volumes can be recommend to minimize the irradiation time when a teletherapy unit is used to irradiate blood.

  6. Global surface solar irradiance product derived from SCIAMACHY FRESCO cloud fraction

    NASA Astrophysics Data System (ADS)

    Wang, Ping; Stammes, Piet; Müller, Richard

    The FRESCO cloud retrieval algorithm has been developed as a simple but fast and efficient algorithm for GOME and SCIAMACHY (Koelemeijer et al., 2001; Fournier et al., 2006; Wang et al., 2008). FRESCO employs the O2 A band at 760 nm to retrieve the effective cloud fraction and cloud pressure using a simple Lambertian cloud model. The effective cloud fraction is a combination of geometric cloud fraction and cloud optical thickness, which yield the same reflectance at the top of the atmosphere as the cloud in the scene. It is well-known that clouds reduce the surface solar irradiance. Therefore the all-sky irradiance can be derived from the clear-sky irradiance with a scaling factor related to the cloud index. The cloud index is very similar to the effective cloud fraction by definition. The MAGIC (Mesoscale Atmospheric Global Irradiance Code) software converts the cloud index to the surface solar irradiance using the Heliosat method (Mueller et al. 2009). The MAGIC algorithm is also used by the CM-SAF surface solar irradiance product for clear sky cases. We applied the MAGIC software to FRESCO effective cloud fraction with slight modifications. In this presentation we will show the FRESCO-SSI monthly mean product and the comparison with the BSRN global irradiance data at Cabauw, the Netherlands and surface solar irradiance measurement at Tibetan plateau in China.

  7. Optimum combinations of visible and near-infrared reflectances for estimating the fraction of photosynthetically available radiation absorbed by plants

    NASA Technical Reports Server (NTRS)

    Podaire, Alain; Deschamps, Pierre-Yves; Frouin, R.; Asrar, Ghassem

    1991-01-01

    A useful parameter to estimate terrestrial primary productivity, that can be sensed from space, is the daily averaged fraction of Photosynthetically Available Radiation (PAR) absorbed by plants. To evaluate this parameter, investigators have relied on the fact that the relative amount of radiation reflected by a vegetated surface in the visible and near infrared depends on the fraction of the surface covered by the vegetation and therefore, correlates with absorbed PAR. They have used vegetation indices, namely normalized difference and simple ratio, to derive absorbed PAR. The problem with normalized difference and simple ratio is first, they are non linear functions of radiance or reflectance and therefore, cannot be readily applied to heterogeneous targets, second, they are used in generally nonlinear relationships, which make time integrals of the indices not proportional to primary productivity, and third, the relationships depend strongly on the type of canopy and background. To remove these limitations, linear combinations of visible and near infrared reflectances at optimum (one or two) viewing zenith angles are proposed.

  8. Immunologic changes after loco-regional radiotherapy and fractionated total body irradiation (TBI) in mice

    SciTech Connect

    De Ruysscher, D.; Waer, M.; Vandeputte, M.; van der Schueren, E. )

    1989-12-01

    The immunologic effects of fractionated irradiation to both hind limbs and the tail of adult mice were investigated. A dose of 34 Gy given in 17 fractions of 2 Gy, 1 fraction per day, 5 days per week, was delivered with a 60Co source. A significant decrease of the total splenocyte count and of the PHA(phytohemagglutinin)-induced proliferation of T cells was found immediately after irradiation. Both parameters normalized within 30 days after irradiation. Immediately after irradiation, the MLC (mixed lymphocyte culture) was supranormal, dropped to 45% 1 week later, and normalized within 1 month after radiotherapy. The NK (natural killer) activity was significantly decreased only the first week after loco-regional irradiation, while the LAK (lymphokine activated killer) activity was not altered at all. The percentage of goat-anti-mouse+ cells (mainly B lymphocytes) was not changed immediately after loco-regional irradiation, but rose to supranormal values (175% of control level) 3 months after irradiation. A persistent decrease of the percentage and the absolute numbers of the Lyt2+ cells (= CD8+ cells, suppressor/cytotoxic phenotype) was observed up to 3 months after irradiation, while the percentage of L3T4+ cells (= CD4+ cells, helper phenotype) remained normal for the total follow-up. No differences in allogeneic skin graft survival could be demonstrated between irradiated and control animals. The observed immunological effects could not be explained by the scatter irradiation to the whole body as total body irradiation (TBI) administered in a dose and dose rate similar to the scatter dose did not result in persistent immunologic changes. No dose-rate effect could be demonstrated in a low dose fractionated total body irradiation schedule. A total body irradiation similar to the scatter dose in humans did not result in significant immunologic changes.

  9. Fractionated sublethal total body irradiation and donor bone marrow infusion for induction of specific allograft tolerance

    SciTech Connect

    Pierce, G.E.; Kimler, B.F.; Thomas, J.H.; Watts, L.M.; Kinnaman, M.L.

    1981-03-01

    Fractionated total lymphoid irradiation (FT-lymphoid-I) plus donor bone marrow (BM) can induce tolerance to skin allografts. In the present study, fractionated total body irradiation (FT-body-I) was studied as an alternative to FT-lymphoid-I. FT-body-I produces less pulmonary and gastrointestinal injury than does single exposure total body irradiation, but because of the decreased capacity of lymphoid tissues to recover from the effects of irradiation between fractions, the effect of FT-body-I on lymphoid cells, when delivered within 24 h, is approximately the same as an equivalent single exposure of total body irradiation. Therefore, FT-body-I, like FT-lymphoid-I, has some selectivity for lymphoid tissues and has the advantage that it can be delivered within the time constraints of ex vivo organ preservation.

  10. Prolongation of experimental islet transplant survival by fractionated splenic irradiation. [Dogs

    SciTech Connect

    Kolb, E.; Casanova, M.; Largiader, F.

    1980-12-01

    Experiments designed to delay the rejection of intrasplenic pancreatic fragment allotransplants in dogs showed increased transplant survival times from 3.1 days (controls) to 5.5 days with fractionated splenic irradiation and to 7.5 days with combined local irradiation and immunosuppressive chemotherapy. Drug treatment alone had no beneficial effect.

  11. Accumulation of DNA Double-Strand Breaks in Normal Tissues After Fractionated Irradiation

    SciTech Connect

    Ruebe, Claudia E.

    2010-03-15

    Purpose: There is increasing evidence that genetic factors regulating the recognition and/or repair of DNA double-strand breaks (DSBs) are responsible for differences in radiosensitivity among patients. Genetically defined DSB repair capacities are supposed to determine patients' individual susceptibility to develop adverse normal tissue reactions after radiotherapy. In a preclinical murine model, we analyzed the impact of different DSB repair capacities on the cumulative DNA damage in normal tissues during the course of fractionated irradiation. Material and Methods: Different strains of mice with defined genetic backgrounds (SCID{sup -/-} homozygous, ATM{sup -/-} homozygous, ATM{sup +/-}heterozygous, and ATM{sup +/+}wild-type mice) were subjected to single (2 Gy) or fractionated irradiation (5 x 2 Gy). By enumerating gammaH2AX foci, the formation and rejoining of DSBs were analyzed in organs representative of both early-responding (small intestine) and late-responding tissues (lung, kidney, and heart). Results: In repair-deficient SCID{sup -/-} and ATM{sup -/-}homozygous mice, large proportions of radiation-induced DSBs remained unrepaired after each fraction, leading to the pronounced accumulation of residual DNA damage after fractionated irradiation, similarly visible in early- and late-responding tissues. The slight DSB repair impairment of ATM{sup +/-}heterozygous mice was not detectable after single-dose irradiation but resulted in a significant increase in unrepaired DSBs during the fractionated irradiation scheme. Conclusions: Radiation-induced DSBs accumulate similarly in acute- and late-responding tissues during fractionated irradiation, whereas the whole extent of residual DNA damage depends decisively on the underlying genetically defined DSB repair capacity. Moreover, our data indicate that even minor impairments in DSB repair lead to exceeding DNA damage accumulation during fractionated irradiation and thus may have a significant impact on normal

  12. Unstable Chromosome Aberrations Do Not Accumulate in Normal Human Fibroblast after Fractionated X-Irradiation

    PubMed Central

    Ojima, Mitsuaki; Ito, Maki; Suzuki, Keiji; Kai, Michiaki

    2015-01-01

    We determined the frequencies of dicentric chromosomes per cell in non-dividing confluent normal human fibroblasts (MRC-5) irradiated with a single 1 Gy dose or a fractionated 1 Gy dose (10X0.1 Gy, 5X0.2 Gy, and 2X0.5 Gy). The interval between fractions was between 1 min to 1440 min. After the completion of X-irradiation, the cells were incubated for 24 hours before re-plating at a low density. Then, demecolcine was administrated at 6 hours, and the first mitotic cells were collected for 42 hours. Our study demonstrated that frequencies of dicentric chromosomes in cells irradiated with a 1 Gy dose at different fractions were significantly reduced if the fraction interval was increased from 1 min to 5 min (p<0.05, χ2-test). Further increasing the fraction interval from 5 up to 1440 min did not significantly affect the frequency of dicentric chromosomes. Since misrejoining of two independent chromosome breaks introduced in close proximity gives rise to dicentric chromosome, our results indicated that such circumstances might be quite infrequent in cells exposed to fractionated X-irradiation with prolonged fraction intervals. Our findings should contribute to improve current estimation of cancer risk from chronic low-dose-rate exposure, or intermittent exposure of low-dose radiation by medical exposure. PMID:25723489

  13. On tests of equal effect per fraction in microcolony assays of survival after fractionated irradiations.

    PubMed

    Taylor, J M

    1985-01-01

    H. D. Thames, Jr. and H. R. Withers [Br. J. Radiol. 53, 1071-1077 (1980)] propose a test of an equal effect per fraction in microcolony assays after fractionated radiation, in which the total effect is measured by counting microcolonies derived from surviving cells in a tissue. The factors considered to influence the cytocidal effect per fraction are incomplete repair, repopulation, and synchrony. The statistics used in the method are criticized and conditions are given under which the test should not be used. An alternative method of testing for an equal effect per fraction is proposed. The pros and cons of each test are discussed and compared using some mouse jejunal crypt cell survival data. PMID:3969441

  14. Effects of titania nanoparticles on phosphorus fractions and its release in resuspended sediments under UV irradiation.

    PubMed

    Luo, Zhuanxi; Wang, Zhenhong; Li, Qingzhao; Pan, Qikun; Yan, Changzhou

    2010-02-15

    Little is known about the effects of nano-TiO(2) on the transformation and transport of phosphorus (P) in resuspended sediments. Chemical sequential extraction was used to investigate P fractions and its release in resuspended sediments under the influence of nano-TiO(2) and UV irradiation. The results showed that the contents of sediment P in all fractions decreased with increasing nano-TiO(2) concentration in UV irradiation, while increased in the dark controls. Furthermore, P release from all fractions was greater in UV irradiation than in the controls. Elevated concentrations (10-50 mg L(-1)) of nano-TiO(2) in UV irradiation significantly facilitated the release of P from organic and Fe oxide fractions, possibly resulting from the partial photo-degradation of organic matter and photochemical transformation of Fe oxides. Apparently, nano-TiO(2) in UV irradiation did not immobilize the loosely sorbed P and reductant soluble P release from the resuspended sediments, possible because (1) some of P released from those fractions were refurnished by the P released from OM; (2) photocatalysis of nano-TiO(2) reduced binding capacity of the resuspended sediments. Our results suggest that the photocatalysis of nano-TiO(2) may offer the potential to regulate the transformation and transport of sediment P in the aquatic environment. PMID:19850408

  15. Clinical and immunologic effects of fractionated total lymphoid irradiation in refractory rheumatoid arthritis

    SciTech Connect

    Trentham, D.E.; Belli, J.A.; Anderson, R.J.; Buckley, J.A.; Goetzl, E.J.; David, J.R.; Austen, K.F.

    1981-10-22

    Ten patients with refractory rheumatoid arthritis were given 3000 rad of fractionated total lymphoid irradiation in an uncontrolled therapeutic trial. Total lymphoid irradiation was associated with objective evidence of considerable clinical improvement in eight patients and with reduced blood lymphocyte counts in all 10. On completion of irradiation, there was an abrogation of lymphocyte reactivity in vitro in the patients with clinical responses, but abnormal antibody activities characteristic of rheumatoid arthritis and normal components of humoral immunity were not suppressed. Partial recrudescence of arthritis occurred shortly after a year after the completion of irradiation and was paralleled by a restitution of lymphocyte concentrations and responsiveness to mitogens to levels similar to those observed before irradiation. These data provide further evidence of T-cell involvement in the pathogenesis of rheumatoid arthritis and demonstrate that total lymphoid irradiation can induce temporary relief, but they do not ascertain whether the natural history of this disease was altered.

  16. Clinical and immunologic effects of fractionated total lymphoid irradiation in refractory rheumatoid arthritis

    SciTech Connect

    Trentham, D.E.; Belli, J.A.Anderson, R.J.; Buckley, J.A.; Goetzl, E.J.; David, J.R.; Austen, K.F.

    1981-10-01

    Ten patients with refractory rheumatoid arthritis were given 3000 rad of fractionated total lymphoid irradiation in an uncontrolled therapeutic trial. Total lymphoid irradiation was associated with objective evidence of considerable clinical improvement in eight patients and with reduced blood lymphocyte counts in all 10. On completion of irradiation, there was an abrogation of lymphocyte reactivity in vitro in the patients with clinical responses, but abnormal antibody activities characteristic of rheumatoid arthritis and normal components of humoral immunity were not suppressed. Partial recrudescence of arthritis occurred shortly before a year after the completion of irradiation and was paralleled by a restitution of lymphocyte concentrations and responsiveness to mitogens to levels similar to those observed before irradiation. These data provide further evidence of T-cell involvement in the pathogenesis of rheumatoid arthritis and demonstrate that total lymphoid irradiation can induce temporary relief, but they do not ascertain whether the natural history of this disease was altered.

  17. Role of Rad52 in fractionated irradiation induced signaling in A549 lung adenocarcinoma cells.

    PubMed

    Ghosh, Somnath; Krishna, Malini

    2012-01-01

    The effect of fractionated doses of γ-irradiation (2Gy per fraction over 5 days), as delivered in cancer radiotherapy, was compared with acute doses of 10 and 2Gy, in A549 cells. A549 cells were found to be relatively more radioresistant if the 10Gy dose was delivered as a fractionated regimen. Microarray analysis showed upregulation of DNA repair and cell cycle arrest genes in the cells exposed to fractionated irradiation. There was intense activation of DNA repair pathway-associated genes (DNA-PK, ATM, Rad52, MLH1 and BRCA1), efficient DNA repair and phospho-p53 was found to be translocated to the nucleus of A549 cells exposed to fractionated irradiation. MCF-7 cells responded differently in fractionated regimen. Silencing of the Rad52 gene in fractionated group of A549 cells made the cells radiosensitive. The above result indicated increased radioresistance in A549 cells due to the activation of Rad52 gene. PMID:22001234

  18. Use of narrow-band spectra to estimate the fraction of absorbed photosynthetically active radiation

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G.; Huemmrich, Karl F.; Goward, Samuel N.

    1990-01-01

    A novel approach is proposed for using high-spectral resolution imagers to estimate the fraction of photosynthetically active radiation adsorbed, f(apar), by vegetated land surfaces. In comparison to approaches using broad-band vegetation indices, the proposed method appears to be relatively insensitive to the reflectance of nonphotosynthetically active material beneath the canopy, such as leaf litter or soil. The method is based on a relationship between the second derivative of the reflectance vs wavelength function for terrestrial vegetation and f(apar). The relationship can be defined by the second derivatives in either of two windows, one in the visible region centered at 0.69 micron, another in the near-infrared region centered at 0.74 micron.

  19. Monitoring PAI-1 and VEGF Levels in 6 Human Squamous Cell Carcinoma Xenografts During Fractionated Irradiation

    SciTech Connect

    Bayer, Christine; Kielow, Achim; Schilling, Daniela; Maftei, Constantin-Alin; Zips, Daniel; Yaromina, Ala; Baumann, Michael; Molls, Michael; Multhoff, Gabriele

    2012-11-01

    Purpose: Previous studies have shown that the plasminogen activator inhibitor type-1 (PAI-1) and vascular endothelial growth factor (VEGF) are regulated by hypoxia and irradiation and are involved in neoangiogenesis. The aim of this study was to determine in vivo whether changes in PAI-1 and VEGF during fractionated irradiation could predict for radiation resistance. Methods and Materials: Six xenografted tumor lines from human squamous cell carcinomas (HSCC) of the head and neck were irradiated with 0, 3, 5, 10, and 15 daily fractions of 2 Gy. The PAI-1 and VEGF antigen levels in tumor lysates were determined by enzyme-linked immunosorbent assay kits. The amounts of PAI-1 and VEGF were compared with the dose to cure 50% of tumors (TCD{sub 50}). Colocalization of PAI-1, pimonidazole (hypoxia), CD31 (endothelium), and Hoechst 33342 (perfusion) was examined by immunofluorescence. Results: Human PAI-1 and VEGF (hVEGF) expression levels were induced by fractionated irradiation in UT-SCC-15, UT-SCC-14, and UT-SCC-5 tumors, and mouse VEGF (msVEGF) was induced only in UT-SCC-5 tumors. High hVEGF levels were significantly associated with radiation sensitivity after 5 fractions (P=.021), and high msVEGF levels were significantly associated with radiation resistance after 10 fractions (P=.007). PAI-1 staining was observed in the extracellular matrix, the cytoplasm of fibroblast-like stroma cells, and individual tumor cells at all doses of irradiation. Colocalization studies showed PAI-1 staining close to microvessels. Conclusions: These results indicate that the concentration of tumor-specific and host-specific VEGF during fractionated irradiation could provide considerably divergent information for the outcome of radiation therapy.

  20. Curcumin Stimulates the Antioxidant Mechanisms in Mouse Skin Exposed to Fractionated γ-Irradiation.

    PubMed

    Jagetia, Ganesh Chandra; Rajanikant, Golgod Krishnamurthy

    2015-01-01

    Fractionated irradiation is one of the important radiotherapy regimens to treat different types of neoplasia. Despite of the immense therapeutic gains accrued by delivering fractionated irradiation to tumors, the radiation burden on skin increases significantly. Low doses of irradiation to skin adversely affect its molecular and metabolic status. The use of antioxidant/s may help to alleviate the radiation-induced changes in the skin and allow delivering a higher dose of radiation to attain better therapeutic gains. Curcumin is an antioxidant and a free radical scavenging dietary supplement, commonly used as a flavoring agent in curries. Therefore, the effect of 100 mg/kg body weight curcumin was studied on the antioxidant status of mice skin exposed to a total dose of 10, 20 and 40 Gy γ-radiation below the rib cage delivered as a single fraction of 2 Gy per day for 5, 10 or 20 days. Skin biopsies from both the curcumin treated or untreated irradiated groups were collected for the biochemical estimations at various post-irradiation times. The irradiation of animals caused a dose dependent decline in the glutathione concentration, glutathione peroxidase, and superoxide dismutase activities and increased the lipid peroxidation in the irradiated skin. Curcumin treatment before irradiation resulted in a significant rise in the glutathione concentration and activities of both the glutathione peroxidase and superoxide dismutase enzymes in mouse skin, whereas lipid peroxidation declined significantly. The present study indicates that curcumin treatment increased the antioxidant status of mouse exposed to different doses of fractionated γ-radiation. PMID:26785336

  1. Seasonal Variation in Fraction of Absorbed Photosynthetically Active Radiation and Vegetation Properties in Burned Forests in Interior Alaska

    NASA Astrophysics Data System (ADS)

    Iwata, H.; Harazono, Y.; Iwama, C.; Ueyama, M.

    2011-12-01

    Wildfire is a major disturbance in boreal forest ecosystems, and it significantly influences carbon exchange processes. It is important to explicitly incorporate burned areas in estimating regional carbon dioxide (CO2) exchange. A simple approach to quantify regional CO2 exchange is an application of a light-use efficiency model with satellite data. The model calculates CO2 uptake from light-use efficiency and absorbed photosynthetically active radiation (PAR). In the regional application, the fraction of absorbed PAR (FAPAR) provided from MODIS satellite data, together with incident PAR, is often used to calculate absorbed PAR. In spite of the importance of FAPAR in estimating CO2 uptake, an earlier study revealed that the MODIS FAPAR data are overestimated for a burned boreal forest. This study aims to provide ground truth data to validate MODIS FAPAR in other burned boreal forests. It also focuses on obtaining an empirical relationship to estimate seasonal and interannual variation in FAPAR from satellite data such as the normalized difference vegetation index (NDVI) in the early stage of recovery after wildfire. We observed incident, reflected, and transmitted PAR to obtain FAPAR in one- and six-year-old burned black spruce forests. Vegetation properties such as NDVI, leaf area index (LAI), and vegetation cover were also observed to explain seasonal variation of FAPAR. CO2 flux was also continuously monitored using the eddy covariance technique. The analysis showed that MODIS FAPAR was overestimated in the two burned forests, and the degree of overestimation was especially large for the younger burned forest. The relationship between FAPAR and NDVI was similar at the two burned forests, implying that this single relationship can be applied to estimate FAPAR from MODIS NDVI regardless of age after wildfire for the early stage of recovery.

  2. Mechanical cutting of irradiated reactor internal components

    SciTech Connect

    Anderson, Michael G.

    2008-01-15

    Mechanical cutting methods to volume reduce and package reactor internal components are now a viable solution for stakeholders challenged with the retirement of first generation nuclear facilities. The recent completion of the removal of the Reactor Vessel Internals (RVI) from within the Sacramento Municipal Utility District's (SMUD) Rancho Seco Nuclear Power Plant demonstrates that unlike previous methods, inclusive of plasma arc and abrasive water-jet cutting, mechanical cutting minimizes exposure to workers, costly water cleanup, and excessive secondary waste generation. Reactor internal components were segmented, packaged, and removed from the reactor building for shipment or storage, allowing the reactor cavity to be drained and follow-on reactor segmentation activities to proceed in the dry state. Area exposure rates at the work positions during the segmentation process were generally 1 mR per hr. Radiological exposure documented for the underwater segmentation processes totaled 13 person rem. The reactor internals weighing 343,000 pounds were segmented into over 200 pieces for maximum shipping package efficiency and produced 5,600 lb of stainless steel chips and shavings which were packaged in void spaces of existing disposal containers, therefore creating no additional disposal volume. Because no secondary waste was driven into suspension in the reactor cavity water, the water was free released after one pass through a charcoal bed and ion exchange filter system. Mechanical cutting techniques are capable of underwater segmentation of highly radioactive components on a large scale. This method minimized radiological exposure and costly water cleanup while creating no secondary waste.

  3. Exploratory Study of the Prognostic Value of Microenvironmental Parameters During Fractionated Irradiation in Human Squamous Cell Carcinoma Xenografts

    SciTech Connect

    Yaromina, Ala; Kroeber, Theresa; Meinzer, Andreas; Boeke, Simon; Thames, Howard; Baumann, Michael; Zips, Daniel

    2011-07-15

    Purpose: To explore the prognostic value of microenvironmental parameters for local tumor control determined before and during fractionated irradiation. Methods and Materials: Six human squamous cell carcinoma (hSCC) lines were transplanted subcutaneously into the right hind leg of nude mice. Tumors were irradiated with 30 fractions within 6 weeks. Local tumor control was determined 120 days after irradiation. Radiation response was quantified as dose to cure 50% of tumors (TCD{sub 50}). In parallel, untreated and irradiated tumors were excised after injection of pimonidazole (hypoxia marker) and Hoechst 33342 (perfusion marker) for histological evaluation. Results: Pimonidazole hypoxia decreased during fractionated irradiation in the majority of tumor lines. Fraction of perfused vessels and vascular area showed modest changes during fractionated irradiation. Histological parameters before treatment and after three and five fractions did not significantly correlate with TCD{sub 50} after irradiation with 30 fractions within 6 weeks (p > 0.05). Hypoxic volume and perfused vessels after 10 fractions showed a significant association with local tumor control after fractionated irradiation (p = 0.018 and p = 0.019, respectively). None of these parameters remained statistically significant when the p value was adjusted for multiple comparisons. Conclusions: The results from this exploratory study suggest that determination of microenvironmental parameters during treatment provides better prognostic information for the outcome after fractionated radiotherapy than pretreatment parameters, which warrants further investigation and confirmation in experimental and clinical studies.

  4. Evaluation of absorbed dose in irradiated sugar-containing plant material (peony roots) by an ESR method

    NASA Astrophysics Data System (ADS)

    Yamaoki, Rumi; Kimura, Shojiro; Ohta, Masatoshi

    2015-12-01

    The relationship between electron spin resonance (ESR) signal intensity of irradiated plant materials and sugar content was investigated by spectral analysis using peony roots. A weak background signal near g=2.005 was observed in the roots. After a 10 kGy irradiation, the ESR line broadened and the intensity increased, and the spectral characteristics were similar to a typical spectrum of irradiated food containing crystalline sugars. The free radical concentration was nearly stable 30 days after irradiation. The spectrum of peony root 30 days after irradiation was simulated using the summation of the intensities of six assumed components: radical signals derived from (a) sucrose, (b) glucose, (c) fructose, (d) cellulose, (e) the background signal near g=2.005 and (f) unidentified component. The simulated spectra using the six components were in agreement with the observed sample spectra. The intensity of sucrose radical signal in irradiated samples increased proportionally up to 20 kGy. In addition, the intensity of sucrose radical signals was strongly correlated with the sucrose contents of the samples. The results showed that the radiation sensitivity of sucrose in peony roots was influenced little by other plant constituents. There was also a good correlation between the total area of the spectra and the sucrose content, because the sucrose content was higher than that of other sugars in the samples. In peony roots, estimation of the absorbed dose from the ESR signal intensity may be possible by a calibration method based on the sucrose content.

  5. Mathematical models and specific absorbed fractions of photon energy in the nonpregnant adult female and at the end of each trimester of pregnancy

    SciTech Connect

    Stabin, M.G.; Watson, E.E.; Cristy, M.; Ryman, J.C.; Eckerman, K.F.; Davis, J.L.; Marshall, D.; Gehlen, M.K.

    1995-05-08

    Mathematical phantoms representing the adult female at three, six, and nine months of gestation are described. They are modifications of the 15-year-old male/adult female phantom (15-AF phantom) of Cristy and Eckerman (1987). The model of uterine contents includes the fetus, fetal skeleton, and placenta. The model is suitable for dose calculations for the fetus as a whole; individual organs within the fetus (other than the skeleton) are not modeled. A new model for the nonpregnant adult female is also described, comprising (1) the 15-AF phantom; (2) an adjustment to specific absorbed fractions for organ self-dose from photons to better match Reference Woman masses; and (3) computation of specific absorbed fractions with Reference Woman masses from ICRP Publication 23 for both penetrating and nonpenetrating radiations. Specific absorbed fractions for photons emitted from various source regions are tabulated for the new non;pregnant adult female model and the three pregnancy models.

  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. An image-based skeletal model for the ICRP reference adult male-specific absorbed fractions for neutron-generated recoil protons.

    PubMed

    Jokisch, D W; Rajon, D A; Bahadori, A A; Bolch, W E

    2011-11-01

    Recoiling hydrogen nuclei are a principle mechanism for energy deposition from incident neutrons. For neutrons incident on the human skeleton, the small sizes of two contrasting media (trabecular bone and marrow) present unique problems due to a lack of charged-particle (protons) equilibrium. Specific absorbed fractions have been computed for protons originating in the human skeletal tissues for use in computing neutron dose response functions. The proton specific absorbed fractions were computed using a pathlength-based range-energy calculation in trabecular skeletal samples of a 40 year old male cadaver. PMID:21983482

  8. Comprehensive study on regional human intestinal permeability and prediction of fraction absorbed of drugs using the Ussing chamber technique.

    PubMed

    Sjöberg, Åsa; Lutz, Mareike; Tannergren, Christer; Wingolf, Caroline; Borde, Anders; Ungell, Anna-Lena

    2013-01-23

    The purpose of this study was to evaluate the use of human intestinal tissue in Ussing chamber to predict oral and colonic drug absorption and intestinal metabolism. Data on viability, correlation between apparent permeability coefficients (P(app)) and fraction absorbed (f(a)) after oral and colonic administration, regional permeability, active uptake and efflux of drugs as well as intestinal metabolism were compiled from experiments using 159 human donors. Permeability coefficients for up to 28 drugs were determined using one or several of four intestinal regions: duodenum, jejunum, ileum and colon and 10 drugs were studied bidirectionally. Viability was monitored simultaneously with transport experiments by recording potential difference (PD), short-circuit current (SCC) and the resistance (TER). Intestinal metabolism was studied using testosterone and midazolam as probe substrates. There was a steep sigmoidal correlation between P(app) in the Ussing chamber, using jejunal segments, and oral f(a) in humans, for a set of 25 drugs (R(2): 0.85, p<0.01). A clear sigmoidal relationship was also obtained between P(app) in colonic segments and f(a) after colonic administration in humans for a set of 10 drugs (R(2): 0.93, p<0.05). Regional permeability data showed a tendency for highly permeable compounds to have higher or similar P(app) in colon as in the small intestinal segments, while the colonic regions showed a lower P(app) for more polar compounds as well as for d-glucose and l-leucine. Bidirectional transport (mucosa to serosa and serosa to mucosa direction) in jejunum showed well functioning efflux- and uptake asymmetry. Intestinal metabolic extraction during transport across jejunum segments was found for both testosterone and midazolam. In conclusion, viable excised human intestine mounted in the Ussing chamber, is a powerful technique for predicting regional fraction absorbed (f(a)), transporter-mediated uptake or efflux as well as intestinal metabolism of

  9. Effects of single-dose and fractionated cranial irradiation on rat brain accumulation of methotrexate

    SciTech Connect

    Kamen, B.A.; Moulder, J.E.; Kun, L.E.; Ring, B.J.; Adams, S.M.; Fish, B.L.; Holcenberg, J.S.

    1984-11-01

    The effects of single-dose and fractionated whole-brain irradiation on brain methotrexate (MTX) has been studied in a rat model. The amount of MTX present in the brain 24 hr after a single i.p. dose (100 mg/kg) was the same whether animals were sham irradiated or given a single dose of 2000 rads 6 or 48 hr prior to the drug (6.9, 8.3, and 6.8 pmol MTX/g, wet weight, respectively). Animals sham irradiated or given 2000 rads in 10 fractions over 11 days and treated with an average dose of 1.2 mg MTX/kg i.p. twice a week for 24 weeks did not differ significantly in their brain MTX concentration (7.9 and 8.3 pmol MTX/g, wet weight, respectively). Chronically MTX-treated animals became folate deficient whether they were irradiated or not (450 and 670 pmol folate/g, wet weight, brain in MTX-treated and control animals). Thus, MTX accumulates in the brain with acute or chronic administration, and this accumulation is not altered by this amount of brain irradiation.

  10. Dental Enamel Irradiated with Infrared Diode Laser and Photo-Absorbing Cream: Part 2—EDX Study

    PubMed Central

    dos Santos, Edson Aparecido Pereira; Soares, Luís Eduardo Silva; do Espírito Santo, Ana Maria; Martin, Airton Abrahão; Duarte, Danilo Antônio; Pacheco-Soares, Cristina; Brugnera, Aldo

    2009-01-01

    Abstract Objective: The effects of laser-induced compositional changes on the enamel were investigated by energy-dispersive X-ray fluorescence spectrometry (μ-EDX). After cariogenic challenge, we administered treatment of low-level infrared diode laser and a photo-absorbing cream (used to intensify the superficial light absorption). Background Data: Dental caries is considered the most prevalent oral disease. A simple and noninvasive caries preventive regimen is treating tooth enamel with a laser, either alone or in combination with fluoride, which reduces enamel solubility and dissolution rates. High power lasers are still not widely used in private practice. Low-power near-infrared lasers may be an alternative approach. Energy-dispersive μ-EDX is a versatile and nondestructive spectroscopic technique that allows for a qualitative and quantitative elemental analysis of inorganic enamel components, such as calcium and phosphorus. Materials and Methods: Twenty-four extracted or exfoliated caries-free deciduous molars were divided into six groups: 1) control group (CTR-no treatment); 2) infrared laser treatment (L) (λ = 810 nm, 100 mW/cm2, 90 sec, 4.47 J/cm2, 9 J); 3) infrared laser irradiation and photo-absorbing agent (CL); 4) photo-absorbing agent alone (C); 5) infrared laser irradiation and fluoridated photo-absorbing agent (FCL); and 6) fluoridated photo-absorbing agent alone (FC). Samples were analyzed using μ-EDX after two sets of treatments and pH cycling cariogenic challenges. Results: The CL group showed statistically significant increases in calcium and phosphorus (wt%) compared with the CTR group. The Ca/P ratio was similar in the FCL and CTR groups. There was a significant laser-induced reduction compared with the CTR group, and there was a possible modification of the organic balance content in enamel treated with laser and cream. Conclusion: μ-EDX may be able to detect compositional changes in mineral phases of lased enamel under

  11. Therapeutic use of fractionated total body and subtotal body irradiation. [X-rays

    SciTech Connect

    Loeffler, R.K.

    1981-05-01

    Ninety-one patients were treated using fractionated subtotal body (STBI) or total body irradiation (TBI). These patients had generalized lymphomas, Hodgkin's disease, leukemias, myelomas, seminomas, or oat-cell carcinomas. Subtotal body irradiation is delivered to the entire body, except for the skull and extremities. It was expected that a significantly higher radiation dose could be administered with STBI than with TBI. A five- to ten-fold increase in tolerance for STBI was demonstrated. Many of these patients have had long-term emissions. There is little or no treatment-induced symptomatology, and no sanctuary sites.

  12. Single-Pass Intestinal Perfusion (SPIP) and prediction of fraction absorbed and permeability in humans: A study with antiretroviral drugs.

    PubMed

    Dezani, Thaisa Marinho; Dezani, André Bersani; Junior, João Batista da Silva; Serra, Cristina Helena Dos Reis

    2016-07-01

    In recent years, the prediction of oral drug absorption in humans has been a challenge for researchers and many techniques for permeability studies have been developed for several purposes, including biowaiver processes. The Single-Pass Intestinal Perfusion (SPIP) method performed in rats can provide permeability results closest to in vivo condition. The purpose of the present study was to evaluate the intestinal permeability of the antiretroviral drugs lamivudine, stavudine and zidovudine using the SPIP method in rats and to predict their permeability (Peff,humans) and fraction absorbed (Fa) in humans. Metoprolol and fluorescein were used as marker compounds of high and low permeability, respectively. The effective permeability (Peff) results showed that stavudine and zidovudine have high permeability characteristics while lamivudine presented the lowest result. From Peff values obtained in rats, the Peff,humans and Fa were calculated. The use of SPIP in rats and calculations for absorption prediction in humans may indicate the transport mechanisms and/or pre-systemic metabolism involved on permeation processes of drugs, since this model is the closest to in vivo conditions. PMID:27130787

  13. Total internal reflection-based module for fluorescence and absorbance detection

    NASA Astrophysics Data System (ADS)

    Verschooten, Tom; Ottevaere, Heidi; Vervaeke, Michael; Van Erps, Jürgen; Thienpont, Hugo

    2014-07-01

    We present a miniaturized polymer-based micro-optical detection unit for ultraviolet and visible laser-induced fluorescence (LIF) and absorbance (ABS) analysis with an interaction length of 3 mm. We use nonsequential optical ray tracing simulations to model the system and to optimize its performance with respect to optical efficiency and system complexity. The design features a compact optical system combining total internal reflection (TIR) mirrors and refractive optics. The detection module is prototyped with deep proton writing in 2-mm-thick polymethylmethacrylate and quantitatively characterized using a three-dimensional coordinate measurement machine. We demonstrate the proof-of-concept of this TIR mirror-based module for coumarin 480 obtaining limits of detection of 50 pM and 500 nM for LIF and ABS, respectively.

  14. Single high-dose irradiation aggravates eosinophil-mediated fibrosis through IL-33 secreted from impaired vessels in the skin compared to fractionated irradiation.

    PubMed

    Lee, Eun-Jung; Kim, Jun Won; Yoo, Hyun; Kwak, Woori; Choi, Won Hoon; Cho, Seoae; Choi, Yu Jeong; Lee, Yoon-Jin; Cho, Jaeho

    2015-08-14

    We have revealed in a porcine skin injury model that eosinophil recruitment was dose-dependently enhanced by a single high-dose irradiation. In this study, we investigated the underlying mechanism of eosinophil-associated skin fibrosis and the effect of high-dose-per-fraction radiation. The dorsal skin of a mini-pig was divided into two sections containing 4-cm(2) fields that were irradiated with 30 Gy in a single fraction or 5 fractions and biopsied regularly over 14 weeks. Eosinophil-related Th2 cytokines such as interleukin (IL)-4, IL-5, and C-C motif chemokine-11 (CCL11/eotaxin) were evaluated by quantitative real-time PCR. RNA-sequencing using 30 Gy-irradiated mouse skin and functional assays in a co-culture system of THP-1 and irradiated-human umbilical vein endothelial cells (HUVECs) were performed to investigate the mechanism of eosinophil-mediated radiation fibrosis. Single high-dose-per-fraction irradiation caused pronounced eosinophil accumulation, increased profibrotic factors collagen and transforming growth factor-β, enhanced production of eosinophil-related cytokines including IL-4, IL-5, CCL11, IL-13, and IL-33, and reduced vessels compared with 5-fraction irradiation. IL-33 notably increased in pig and mouse skin vessels after single high-dose irradiation of 30 Gy, as well as in irradiated HUVECs following 12 Gy. Blocking IL-33 suppressed the migration ability of THP-1 cells and cytokine secretion in a co-culture system of THP-1 cells and irradiated HUVECs. Hence, high-dose-per-fraction irradiation appears to enhance eosinophil-mediated fibrotic responses, and IL-33 may be a key molecule operating in eosinophil-mediated fibrosis in high-dose-per fraction irradiated skin. PMID:26047701

  15. Toward the development of transcriptional biodosimetry for the identification of irradiated individuals and assessment of absorbed radiation dose.

    PubMed

    Brzóska, Kamil; Kruszewski, Marcin

    2015-08-01

    The most frequently used and the best established method of biological dosimetry at present is the dicentric chromosome assay, which is poorly suitable for a mass casualties scenario. This gives rise to the need for the development of new, high-throughput assays for rapid identification of the subjects exposed to ionizing radiation. In the present study, we tested the usefulness of gene expression analysis in blood cells for biological dosimetry. Human peripheral blood from three healthy donors was X-irradiated with doses of 0 (control), 0.6, and 2 Gy. The mRNA level of 16 genes (ATF3, BAX, BBC3, BCL2, CDKN1A, DDB2, FDXR, GADD45A, GDF15, MDM2, PLK3, SERPINE1, SESN2, TNFRSF10B, TNFSF4, and VWCE) was assessed by reverse transcription quantitative PCR 6, 12, 24, and 48 h after exposure with ITFG1 and DPM1 used as a reference genes. The panel of radiation-responsive genes was selected comprising GADD45A, CDKN1A, BAX, BBC3, DDB2, TNFSF4, GDF15, and FDXR. Cluster analysis showed that ΔC t values of the selected genes contained sufficient information to allow discrimination between irradiated and non-irradiated blood samples. The samples were clearly grouped according to the absorbed doses of radiation and not to the time interval after irradiation or to the blood donor. PMID:25972268

  16. Recovery capacity of glial progenitors after in vivo fission-neutron or X irradiation: age dependence, fractionation and low-dose-rate irradiations.

    PubMed

    Philippo, H; Winter, E A M; van der Kogel, A J; Huiskamp, R

    2005-06-01

    Previous experiments on the radiosensitivity of O-2A glial progenitors determined for single-dose fission-neutron and X irradiation showed log-linear survival curves, suggesting a lack of accumulation of recovery of sublethal damage. In the present study, we addressed this question and further characterized the radiobiological properties of these glial stem cells by investigating the recovery capacity of glial stem cells using either fractionated or protracted whole-body irradiation. Irradiations were performed on newborn, 2-week-old or 12-week-old rats. Fractionated irradiations (four fractions) were performed with 24-h intervals, followed by cell isolations 16- 24 h after the last irradiation. Single-dose irradiations were followed by cell isolation 16-24 h after irradiation or delayed cell isolation (4 days after irradiation) of the O-2A progenitor cells from either spinal cord (newborns) or optic nerve (2- and 12-week-old rats). Results for neonatal progenitor cell survival show effect ratios for both fractionated fission-neutron and X irradiation of the order of 1.8 when compared with single-dose irradiation. A similar ratio was found after single-dose irradiation combined with delayed plating. Comparable results were observed for juvenile and adult optic nerve progenitors, with effect ratios of the order of 1.2. The present investigation clearly shows that fractionated irradiation regimens using X rays or fission neutrons and CNS tissue from rats of various ages results in an increase in O-2A progenitor cell survival while repair is virtually absent. This recovery of the progenitor pool after irradiation can be observed at all ages but is greatest in the neonatal spinal cord and can probably be attributed to repopulation. PMID:15913395

  17. Monte Carlo MCNP-4B energy absorbed fractions in Head and Brain calculated in "The ORNL mathematical phantom series" and in "MIRD 15" mathematical phantoms

    NASA Astrophysics Data System (ADS)

    Valle, Saúl H.; Lorenzo, Daniel M.; Gual, Maritza R.

    2002-08-01

    Due to the use of many new radiopharmaceuticals in Brain imaging there exists the need of predicting absorbed energy and doses during the irradiation process within the head specificity in brain. In order to evaluate the MCNP-4b capability of calculating absorbed energy in Brain and Head we calculated it first using the geometrical data from "The ORNL mathematical phantom series" and subsequently a more anthropomorphic model "current MIRD 15". The results are compared with validated data and the conclusions are shown at the end.

  18. Fractionated beam radiotherapy is a special case of continuous beam radiotherapy when irradiation time is small.

    PubMed

    Biswas, Jayanta; Rajguru, Tapan K; Choudhury, Krishnangshu B; Dutta, Sumita; Sharma, Shyam; Sarkar, Aniruddha

    2013-01-01

    Fractionated beam radiotherapy, in other terms, external beam radiotherapy (EBRT) and continuous beam radiotherapy or Brachytherapy are two modes of radiotherapy techniques. Although in many ways, they appear to be different, radiobiologically, with the help of mathematics, it can be proved that the biological effective dose (BED) of EBRT is similar to BED of Brachytherapy, when irradiation time is small. Here an attempt is made to correlate these two predominant modes of radiotherapy techniques. PMID:24125964

  19. Measured Wavelength-Dependent Absorption Enhancement of Internally Mixed Black Carbon with Absorbing and Nonabsorbing Materials.

    PubMed

    You, Rian; Radney, James G; Zachariah, Michael R; Zangmeister, Christopher D

    2016-08-01

    Optical absorption spectra of laboratory generated aerosols consisting of black carbon (BC) internally mixed with nonabsorbing materials (ammonium sulfate, AS, and sodium chloride, NaCl) and BC with a weakly absorbing brown carbon surrogate derived from humic acid (HA) were measured across the visible to near-IR (550 to 840 nm). Spectra were measured in situ using a photoacoustic spectrometer and step-scanning a supercontinuum laser source with a tunable wavelength and bandwidth filter. BC had a mass-specific absorption cross section (MAC) of 7.89 ± 0.25 m(2) g(-1) at λ = 550 nm and an absorption Ångström exponent (AAE) of 1.03 ± 0.09 (2σ). For internally mixed BC, the ratio of BC mass to the total mass of the mixture was chosen as 0.13 to mimic particles observed in the terrestrial atmosphere. The manner in which BC mixed with each material was determined from transmission electron microscopy (TEM). AS/BC and HA/BC particles were fully internally mixed, and the BC was both internally and externally mixed for NaCl/BC particles. The AS/BC, NaCl/BC, and HA/BC particles had AAEs of 1.43 ± 0.05, 1.34 ± 0.06, and 1.91 ± 0.05, respectively. The observed absorption enhancement of mixed BC relative to the pure BC was wavelength dependent for AS/BC and decreased from 1.5 at λ = 550 nm with increasing wavelength while the NaCl/BC enhancement was essentially wavelength independent. For HA/BC, the enhancement ranged from 2 to 3 and was strongly wavelength dependent. Removal of the HA absorption contribution to enhancement revealed that the enhancement was ≈1.5 and independent of wavelength. PMID:27359341

  20. Physical models, cross sections, and numerical approximations used in MCNP and GEANT4 Monte Carlo codes for photon and electron absorbed fraction calculation

    SciTech Connect

    Yoriyaz, Helio; Moralles, Mauricio; Tarso Dalledone Siqueira, Paulo de; Costa Guimaraes, Carla da; Belonsi Cintra, Felipe; Santos, Adimir dos

    2009-11-15

    Purpose: Radiopharmaceutical applications in nuclear medicine require a detailed dosimetry estimate of the radiation energy delivered to the human tissues. Over the past years, several publications addressed the problem of internal dose estimate in volumes of several sizes considering photon and electron sources. Most of them used Monte Carlo radiation transport codes. Despite the widespread use of these codes due to the variety of resources and potentials they offered to carry out dose calculations, several aspects like physical models, cross sections, and numerical approximations used in the simulations still remain an object of study. Accurate dose estimate depends on the correct selection of a set of simulation options that should be carefully chosen. This article presents an analysis of several simulation options provided by two of the most used codes worldwide: MCNP and GEANT4. Methods: For this purpose, comparisons of absorbed fraction estimates obtained with different physical models, cross sections, and numerical approximations are presented for spheres of several sizes and composed as five different biological tissues. Results: Considerable discrepancies have been found in some cases not only between the different codes but also between different cross sections and algorithms in the same code. Maximum differences found between the two codes are 5.0% and 10%, respectively, for photons and electrons.Conclusion: Even for simple problems as spheres and uniform radiation sources, the set of parameters chosen by any Monte Carlo code significantly affects the final results of a simulation, demonstrating the importance of the correct choice of parameters in the simulation.

  1. Degradation and decoloration of textiles wastewater by electron beam irradiation: Effect of energy, current and absorbed dose

    SciTech Connect

    Bakar, Khomsaton Abu; Zulkafli,; Hashim, Siti A'aisah; Ahmad, Pauzi

    2014-09-03

    In this study, electron beam accelerator (EB) was used to treat textiles wastewater from Rawang Industrial Park, Selangor. The objectives were to determine effective energy, beam current and absorbed dose required for decoloration and degradation of the textiles effluent. The textiles effluent was irradiated in a batch with various energy of 1MeV to 3MeV at constant beam current of 30mA. It was observed that removal of color and COD increases with higher beam energy. The EB energy of 1MeV effectively to removed 58% color and 19% COD. For textile effluent sample irradiated at fix energy of 1MeV and 3Mev but at different beam current 10mA, 20mA and 30mA. It was observed that removal of color and COD increases with the increased of beam current at each energy. However removal of color was significantly better at 1Mev as compared to 3Mev. In the case of textiles effluent, irradiated at doses of 17, 20,25,30, 35, 100 and 200kGy using 30 kW power of EB (1Mev, 30mA), results shows removal of BOD{sub 5}, COD and color were in the range 9%-33%, 14%-38% and 43%-78% respectively.

  2. Development of in vitro models for investigating spatially fractionated irradiation: physics and biological results

    NASA Astrophysics Data System (ADS)

    Blockhuys, S; Vanhoecke, B; Paelinck, L; Bracke, M; DeWagter, C

    2009-03-01

    We present different in vitro experimental models which allow us to evaluate the effect of spatially fractionated dose distributions on metabolic activity. We irradiated a monolayer of MCF-7/6 human breast cancer cells with a steep and a smooth 6 MV x-ray dose gradient. In the steep gradient model, we irradiated the cells with three separate small fields. We also developed two smooth gradient models. In the first model, the cells are cultured in a T25 flask and irradiated with a smooth dose gradient over the length of the flask, while in the second one, the cells are cultured in a 96-well plate and also irradiated over the length of the plate. In an attempt to correlate the spatially fractionated dose distributions with metabolic activity, the effect of irradiation was evaluated by means of the MTT assay. This assay is used to determine the metabolic activity by measuring the amount of formazan formed after the conversion of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) by cellular dehydrogenases. The results obtained with our different models suggest a dose-specific effect on metabolic activity, characterized by an increased formazan optical density occurring in the dose range 1.0-4.0 Gy in the steep dose gradient model and in the dose ranges 4.2-6.5 Gy and 2.3-5.1 Gy in the two smooth dose gradient models. The corresponding times for maximal formazan accumulation were 5-7 days in the steep dose gradient model and day 9-13 and day 9-11 in the smooth dose gradient models. Altogether, our results suggest that the MTT assay may be used as a biological dose-response meter to monitor the radiotherapeutic effectiveness.

  3. Single high-dose irradiation aggravates eosinophil-mediated fibrosis through IL-33 secreted from impaired vessels in the skin compared to fractionated irradiation

    SciTech Connect

    Lee, Eun-Jung; Kim, Jun Won; Yoo, Hyun; Kwak, Woori; Choi, Won Hoon; Cho, Seoae; Choi, Yu Jeong; Lee, Yoon-Jin; Cho, Jaeho

    2015-08-14

    We have revealed in a porcine skin injury model that eosinophil recruitment was dose-dependently enhanced by a single high-dose irradiation. In this study, we investigated the underlying mechanism of eosinophil-associated skin fibrosis and the effect of high-dose-per-fraction radiation. The dorsal skin of a mini-pig was divided into two sections containing 4-cm{sup 2} fields that were irradiated with 30 Gy in a single fraction or 5 fractions and biopsied regularly over 14 weeks. Eosinophil-related Th2 cytokines such as interleukin (IL)-4, IL-5, and C–C motif chemokine-11 (CCL11/eotaxin) were evaluated by quantitative real-time PCR. RNA-sequencing using 30 Gy-irradiated mouse skin and functional assays in a co-culture system of THP-1 and irradiated-human umbilical vein endothelial cells (HUVECs) were performed to investigate the mechanism of eosinophil-mediated radiation fibrosis. Single high-dose-per-fraction irradiation caused pronounced eosinophil accumulation, increased profibrotic factors collagen and transforming growth factor-β, enhanced production of eosinophil-related cytokines including IL-4, IL-5, CCL11, IL-13, and IL-33, and reduced vessels compared with 5-fraction irradiation. IL-33 notably increased in pig and mouse skin vessels after single high-dose irradiation of 30 Gy, as well as in irradiated HUVECs following 12 Gy. Blocking IL-33 suppressed the migration ability of THP-1 cells and cytokine secretion in a co-culture system of THP-1 cells and irradiated HUVECs. Hence, high-dose-per-fraction irradiation appears to enhance eosinophil-mediated fibrotic responses, and IL-33 may be a key molecule operating in eosinophil-mediated fibrosis in high-dose-per fraction irradiated skin. - Highlights: • Single high-dose irradiation aggravates eosinophil-mediated fibrosis through IL-33. • Vascular endothelial cells damaged by high-dose radiation secrete IL-33. • Blocking IL-33 suppressed migration of inflammatory cells and cytokine secretion. • IL

  4. Hippocampal Neuron Number Is Unchanged 1 Year After Fractionated Whole-Brain Irradiation at Middle Age

    SciTech Connect

    Shi Lei Molina, Doris P.; Robbins, Michael E.; Wheeler, Kenneth T.; Brunso-Bechtold, Judy K.

    2008-06-01

    Purpose: To determine whether hippocampal neurons are lost 12 months after middle-aged rats received a fractionated course of whole-brain irradiation (WBI) that is expected to be biologically equivalent to the regimens used clinically in the treatment of brain tumors. Methods and Materials: Twelve-month-old Fischer 344 X Brown Norway male rats were divided into WBI and control (CON) groups (n = 6 per group). Anesthetized WBI rats received 45 Gy of {sup 137}Cs {gamma} rays delivered as 9 5-Gy fractions twice per week for 4.5 weeks. Control rats were anesthetized but not irradiated. Twelve months after WBI completion, all rats were anesthetized and perfused with paraformaldehyde, and hippocampal sections were immunostained with the neuron-specific antibody NeuN. Using unbiased stereology, total neuron number and the volume of the neuronal and neuropil layers were determined in the dentate gyrus, CA3, and CA1 subregions of hippocampus. Results: No differences in tissue integrity or neuron distribution were observed between the WBI and CON groups. Moreover, quantitative analysis demonstrated that neither total neuron number nor the volume of neuronal or neuropil layers differed between the two groups for any subregion. Conclusions: Impairment on a hippocampal-dependent learning and memory test occurs 1 year after fractionated WBI at middle age. The same WBI regimen, however, does not lead to a loss of neurons or a reduction in the volume of hippocampus.

  5. Response of human tumor cell lines in vitro to fractionated irradiation.

    PubMed

    Matthews, J H; Meeker, B E; Chapman, J D

    1989-01-01

    The surviving fraction of human tumor cell lines after 2 Gy (SF2) varies between 0.1 and 0.8. It has been postulated that differences in inherent radiosensitivity of tumor cells are a major determinant of radiation response in vivo. Assays of inherent radiosensitivity based on acute survival are being developed as predictors of tumor response which often assume that the same inherent radiosensitivity persists throughout a fractionated treatment. We have investigated the response of 2 human tumor cell lines (A549 and MCF7) with different inherent radiosensitivities to in vitro fractionated irradiation. A549 cells had an SF2 of 0.62 and a mean inactivation dose (D) of 3.07 Gy whereas MCF7 cells had an SF2 of 0.30 and a D of 1.52 Gy. Split dose repair capacity (at equal survival levels) was less for A549 than for MCF7 cells and recovery kinetics for both cell lines were substantially longer than those of rodent cell lines. Survival after 5 fractions of 2 Gy given 12 hr apart at 37 degrees C was near to that predicted from the acute survival curve, assuming complete repair and no proliferation. Acute survival of A549 cells which survived 5 fractions of 2 Gy given 12 hr apart was similar to the acute survival of unirradiated cells. When A549 cells were incubated at 22 degrees C between 5 fractions of 2 Gy given 12 hr apart, proliferation and split dose repair were substantially inhibited. These studies support the proposals to use in vitro inherent radiosensitivity assays for the prediction of in vivo response of tumors to fractionated treatment. PMID:2912934

  6. Comparison of hyperbaric xoygen and misonidazole in fractionated irradiation of murine tumors. [/sup 137/Cs

    SciTech Connect

    Suit, H.D.; Maimonis, P.; Michaels, H.B.; Sedlacek, R.

    1981-08-01

    The enhancement ratios for hyperbaric oxygen (O/sub 2/3ATA) and for misonidazole (0.3 mg/g body wt) for fractionated irradiation (5 or 10 equal doses) of two spontaneous tumors and of normal skin of the C3H mouse have been determined. Acute skin reactions were scored for mice irradiated 18 days after plucking hair from the leg. Enhancement ratios for the TCD/sub 50/ values were virtually the same for O/sub 2/3ATA and misonidazole, 1.45 to 1.55. For acute skin reaction the enhancement ratio was higher for O/sub 2/3ATA, i.e., 1.94 vs 1.54 for misonidazole.

  7. Enrofloxacin and marbofloxacin in horses: comparison of pharmacokinetic parameters, use of urinary and metabolite data to estimate first-pass effect and absorbed fraction.

    PubMed

    Peyrou, M; Bousquet-Melou, A; Laroute, V; Vrins, A; Doucet, M Y

    2006-10-01

    Enrofloxacin and marbofloxacin are two veterinary fluoroquinolones used to treat severe bacterial infections in horses. A repeated measures study has been designed to compare their pharmacokinetic parameters, to investigate their bioavailability and to estimate their absorbed fraction and first-pass effect by using plasma, urinary and metabolite data collected from five healthy mares. Clearance and V(d(ss)) were greater for enrofloxacin (mean +/- SD = 6.34 +/- 1.5 mL/min/kg and 2.32 +/- 0.32 L/kg, respectively) than for marbofloxacin (4.62 +/- 0.67 mL/min/kg and 1.6 +/- 0.25 L/kg, respectively). Variance of the AUC(0-inf) of marbofloxacin was lower than that for enrofloxacin, with, respectively, a CV = 15% and 26% intravenously and a CV = 31% and 55% after oral administration. Mean oral bioavailability was not significantly different between marbofloxacin (59%) and enrofloxacin (55%). The mean percentage of the dose eliminated unchanged in urine was significantly higher for marbofloxacin (39.7%) than that for enrofloxacin (3.4%). Absorbed fraction and first-pass effect were only determinable for enrofloxacin, whereas the percentage of the dose absorbed in the portal circulation was estimated to be 78% and the fraction not extracted during the first pass through the liver was 65%. Consequently, the moderate observed bioavailability of enrofloxacin appears to be mainly caused by hepatic first-pass effect. PMID:16958777

  8. Extrapolation of Normal Tissue Complication Probability for Different Fractionations in Liver Irradiation

    SciTech Connect

    Tai An; Erickson, Beth; Li, X. Allen

    2009-05-01

    Purpose: The ability to predict normal tissue complication probability (NTCP) is essential for NTCP-based treatment planning. The purpose of this work is to estimate the Lyman NTCP model parameters for liver irradiation from published clinical data of different fractionation regimens. A new expression of normalized total dose (NTD) is proposed to convert NTCP data between different treatment schemes. Method and Materials: The NTCP data of radiation- induced liver disease (RILD) from external beam radiation therapy for primary liver cancer patients were selected for analysis. The data were collected from 4 institutions for tumor sizes in the range of of 8-10 cm. The dose per fraction ranged from 1.5 Gy to 6 Gy. A modified linear-quadratic model with two components corresponding to radiosensitive and radioresistant cells in the normal liver tissue was proposed to understand the new NTD formalism. Results: There are five parameters in the model: TD{sub 50}, m, n, {alpha}/{beta} and f. With two parameters n and {alpha}/{beta} fixed to be 1.0 and 2.0 Gy, respectively, the extracted parameters from the fitting are TD{sub 50}(1) = 40.3 {+-} 8.4Gy, m =0.36 {+-} 0.09, f = 0.156 {+-} 0.074 Gy and TD{sub 50}(1) = 23.9 {+-} 5.3Gy, m = 0.41 {+-} 0.15, f = 0.0 {+-} 0.04 Gy for patients with liver cirrhosis scores of Child-Pugh A and Child-Pugh B, respectively. The fitting results showed that the liver cirrhosis score significantly affects fractional dose dependence of NTD. Conclusion: The Lyman parameters generated presently and the new form of NTD may be used to predict NTCP for treatment planning of innovative liver irradiation with different fractionations, such as hypofractioned stereotactic body radiation therapy.

  9. Total body irradiation in bone marrow transplantation: the influence of fractionation and delay of marrow infusion

    SciTech Connect

    Lichter, A.S.; Tracy, D.; Lam, W.C.; Order, S.E.

    1980-03-01

    Bone marrow transplantation (BMT) after total body irradiation (TBI) and cyclophosphamide is being employed increasingly in the therapy of end stage leukemia. Interstitial pneumonitis (IP) represents a major acute toxicity after allogeneic transplantation. A more rapid reconstitution of lymphoid organs and bone marrow post transplant may result in increased immune competence and hence fewer opportunistic pulmonary infections and IP. By delaying the infusion of marrow to 72 hr after TBI (1250 rad at 7.5 rad/min) instead of the customary 24 hr, we can demonstrate an increase in initial repopulation of thymus, spleen and bone marrow, with syngeneic transplants in Lewis rats. Interstitial pneumonitis may also be caused, in part, by the pulmonary toxicity of large single exposures of TBI. Clinical and laboratory data suggest that fractionated TBI may be less toxic to the lung. When fractionated TBI (625 rad x 2, 7.5 rad/min) is compared to single dose TBI (1250 rad, 7.5 rad/min), and increased initial repopulation of lymphoid organs is observed when fractionated therapy is employed. Delay in marrow infusion and fractionation of TBI exposure may have clinical advantages in patients who receive BMT.

  10. Cataracts after total body irradiation and marrow transplantation: a sparing effect of dose fractionation

    SciTech Connect

    Deeg, H.J.; Flournoy, N.; Sullivan, K.M.; Sheehan, K.; Buckner, C.D.; Sanders, J.E.; Storb, R.; Witherspoon, R.P.; Thomas, E.D.

    1984-07-01

    Two hundred seventy-seven patients, who have been followed for 1 to 12 years after marrow transplantation, have been examined for cataract development. In preparation for transplantation, 96 patients with aplastic anemia were conditioned with chemotherapy only, while 181 patients (two with aplastic anemia and 179 with a hematologic malignancy) were conditioned with a regimen of total body irradiation (TBI) and chemotherapy. TBI was delivered from two opposing /sup 60/Co sources at an exposure rate of 4 to 8 cGy/min, either as a single dose of 10 Gy (105 patients) or in fractions (76 patients). To date, 86 patients have developed cataracts. Kaplan-Meier product limit estimates of the incidence of cataracts for patients given chemotherapy only and no TBI, single-dose TBI, and fractionated TBI are 19, 80, 18%, respectively. On the basis of proportional hazards regression analyses, patients given single-dose TBI had a relative risk of developing cataracts that was 4.7-fold higher than in patients given fractionated TBI or chemotherapy only, suggesting a significant sparing effect with use of TBI dose fractionation.

  11. Electron absorbed fractions of energy and S-values in an adult human skeleton based on µCT images of trabecular bone

    NASA Astrophysics Data System (ADS)

    Kramer, R.; Richardson, R. B.; Cassola, V. F.; Vieira, J. W.; Khoury, H. J.; Lira, C. A. B. de O.; Robson Brown, K.

    2011-03-01

    When the human body is exposed to ionizing radiation, among the soft tissues at risk are the active marrow (AM) and the bone endosteum (BE) located in tiny, irregular cavities of trabecular bone. Determination of absorbed fractions (AFs) of energy or absorbed dose in the AM and the BE represent one of the major challenges of dosimetry. Recently, at the Department of Nuclear Energy at the Federal University of Pernambuco, a skeletal dosimetry method based on µCT images of trabecular bone introduced into the spongiosa voxels of human phantoms has been developed and applied mainly to external exposure to photons. This study uses the same method to calculate AFs of energy and S-values (absorbed dose per unit activity) for electron-emitting radionuclides known to concentrate in skeletal tissues. The modelling of the skeletal tissue regions follows ICRP110, which defines the BE as a 50 µm thick sub-region of marrow next to the bone surfaces. The paper presents mono-energetic AFs for the AM and the BE for eight different skeletal regions for electron source energies between 1 keV and 10 MeV. The S-values are given for the beta emitters 14C, 59Fe, 131I, 89Sr, 32P and 90Y. Comparisons with results from other investigations showed good agreement provided that differences between methodologies and trabecular bone volume fractions were properly taken into account. Additionally, a comparison was made between specific AFs of energy in the BE calculated for the actual 50 µm endosteum and the previously recommended 10 µm endosteum. The increase in endosteum thickness leads to a decrease of the endosteum absorbed dose by up to 3.7 fold when bone is the source region, while absorbed dose increases by ~20% when the beta emitters are in marrow.

  12. Pathologic findings in canine brain irradiated with fractionated fast neutrons or photons

    SciTech Connect

    Zook, B.C.; Bradley, E.W.; Casarett, G.W.; Rogers, C.C.

    1980-12-01

    Thirty-seven adult male purebred beagles received total doses of 1333, 2000, 3000, or 4500 rad of fast neutrons (15 MeV av) in 4 fractions/week for 7 weeks to the entire brain. Nineteen dogs received 4000, 6000, or 9000 rad of photons (/sup 60/Co) in an identical fractionation pattern. Dogs receiving 4500, 3000, and 2000 rad of neutrons and 9000 rad of photons developed neurologic signs and died or were euthanatized when moribund followed irradiation. Cerebrospinal fluid contained excess protein and erythrocytes during and sometimes before the generally brief course. The onset of neurologic symptoms was usually followed by a moribund state in less than 48 h. The relative biological effectiveness (RBE) as measured by onset of neurologic symptoms and mortality was greater than 4.5. Gross changes included hemorrhage, edema, and malacia primarily in the white matter, especially the corona radiata, cerebellar white matter, corpus callosum, and corpus fornicis. One beagle developed a brain tumor and died 1207 days following 1333-rad neutron irradiation.

  13. Engraftment of DLA-nonidentical unrelated canine marrow after high-dose fractionated total body irradiation

    SciTech Connect

    Deeg, H.J.; Storb, R.; Shulman, H.M.; Weiden, P.L.; Graham, T.C.; Thomas, E.D.

    1982-04-01

    Marrow transplants were carried out between unrelated DLA-nonidentical dogs. Recipients were conditioned for transplantation by total body irradiation (TBI) given eigher as a single dose of 9 Gy (900 rad) or fractionated in three increments of 6 Gy (600 rad) each at intervals of 48 hr. All recipients received marrow, less than or equal to 4 x 10(8) cells/kg, and no buffy coat cells. No immunosuppression was given after grafting. All 10 dogs given single dose total body irradiation failed to show engraftment and died with marrow aplasia and infectious complications (median survival 12 days). In contrast, all 10 dogs given fractionated TBI had sustained engraftment and died with graft-versus-host disease (GVHD) and infectious complications (median survival 12.5 days). None of the dogs died from radiation-induced gastroenteritis. In conclusion, resistance to DLA-nonidentical unrelated marrow grafts can be abrogated by high-dose TBI. This technique may allow hemopoietic engraftment even after i vitro manipulation of the marrow such as lymphocyte depletion by cell separation or treatment with anti-T cell antisera.

  14. Engraftment of DLA-nonidentical unrelated canine marrow after high-dose fractionated total body irradiation

    SciTech Connect

    Deeg, H.J.; Storb, R.; Shulman, H.M.; Weiden, P.L.; Graham, T.C.; Thomas, E.D.

    1982-04-01

    Marrow transplants were carried out between unrelated DLA-nonidentical dogs. Recipients were conditioned for transplantation by total body irradiation (TBI) given either as a single dose of 9 Gy (900 rad) or fractionated in three increments of 6 Gy (600 rad) each at intervals of 48 hr. All recipients received marrow, less than or equal to to 4 X 10/sup 8/ cells/kg, and no buffy coat cells. No immunosuppression was given after grafting. All 10 dogs given single-dose total body irradiation failed to show engraftment and died with marrow aplasia and infectious complications (median survival 12 days). In contrast, all 10 dogs given fractionated TBI had sustained engraftment and died with graft-versus-host disease (GVHD) and infectious complications (median survival 12.5 days). None of the dogs died from radiation-induced gastroenteritis.In conclusion, resistance to DLA-nonidentical unrelated marrow grafts can be abrogated by high-dose TBI. This technique may allow hemopoietic engraftment even after in vitro manipulation of the marrow such as lymphocyte depletion by cell separation or treatment with anti-T cell antisera.

  15. Fractional absorption of active absorbable algal calcium (AAACa) and calcium carbonate measured by a dual stable-isotope method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With the use of stable isotopes, this study aimed to compare the bioavailability of active absorbable algal calcium (AAACa), obtained from oyster shell powder heated to a high temperature, with an additional heated seaweed component (Heated Algal Ingredient, HAI), with that of calcium carbonate. In ...

  16. Simvastatin Ameliorates Radiation Enteropathy Development After Localized, Fractionated Irradiation by a Protein C-Independent Mechanism

    SciTech Connect

    Wang Junru; Boerma, Marjan; Fu Qiang; Kulkarni, Ashwini; Fink, Louis M.; Hauer-Jensen, Martin . E-mail: mhjensen@life.uams.edu

    2007-08-01

    Purpose: Microvascular injury plays a key role in normal tissue radiation responses. Statins, in addition to their lipid-lowering effects, have vasculoprotective properties that may counteract some effects of radiation on normal tissues. We examined whether administration of simvastatin ameliorates intestinal radiation injury, and whether the effect depends on protein C activation. Methods and Materials: Rats received localized, fractionated small bowel irradiation. The animals were fed either regular chow or chow containing simvastatin from 2 weeks before irradiation until termination of the experiment. Groups of rats were euthanized at 2 weeks and 26 weeks for assessment of early and delayed radiation injury by quantitative histology, morphometry, and quantitative immunohistochemistry. Dependency on protein C activation was examined in thrombomodulin (TM) mutant mice with deficient ability to activate protein C. Results: Simvastatin administration was associated with lower radiation injury scores (p < 0.0001), improved mucosal preservation (p = 0.0009), and reduced thickening of the intestinal wall and subserosa (p = 0.008 and p = 0.004), neutrophil infiltration (p = 0.04), and accumulation of collagen I (p = 0.0003). The effect of simvastatin was consistently more pronounced for delayed than for early injury. Surprisingly, simvastatin reduced intestinal radiation injury in TM mutant mice, indicating that the enteroprotective effect of simvastatin after localized irradiation is unrelated to protein C activation. Conclusions: Simvastatin ameliorates the intestinal radiation response. The radioprotective effect of simvastatin after localized small bowel irradiation does not appear to be related to protein C activation. Statins should undergo clinical testing as a strategy to minimize side effects of radiation on the intestine and other normal tissues.

  17. Fractionated total lymphoid irradiation as preparative immunosuppression in high risk renal transplantation: clinical and immunological studies

    SciTech Connect

    Najarian, J.S.; Ferguson, R.M.; Sutherland, D.E.; Slavin, S.; Kim, T.; Kersey, J.; Simmons, R.S.

    1982-10-01

    Twenty-two patients at high risk to reject renal allografts have been treated with fractionated total lymphoid irradiation (FTLI) prior to transplantation of primary (2), secondary (16) or teritary (4) renal allografts. All patients undergoing retransplantation had rapidly rejected previous grafts. At 24 months following transplantation, 72% of grafts were functioning in the TLI group compared with a 38% graft function in an historical control group of recipients receiving secondary or tertiary grafts and treated with conventional immunosuppression. Important variables in determining success of transplantation following fractionated TLI include the dose of TLI, the interval from radiation to transplantation, and maintenance, post-transplant immunosuppressive therapy. Optimal results were achieved with 2500 rads delivered in 100 rad fractions followed by transplantation within two weeks, and a tapering prednisone schedule and maintenance azathioprine post-transplantation. Seventeen patients had significant complications of the radiation treatment and there was one death, prior to transplantation, associated with pneumonitis. In vitro assessment of immune function demonstrated marked peripheral T cell depletion and loss of in vitro responsiveness to mitogen and allogeneic stimulation following FTLI. The administration of donor bone marrow at the time of transplantation did not produce chimerism. The results suggest that when properly utilized FTLI can produce effective adjunctive immunosuppression for clinical transplantation.

  18. Fractionated total lymphoid irradiation as preparative immunosuppression in high risk renal transplantation

    SciTech Connect

    Najarian, J.S.; Ferguson, R.M.; Sutherland, D.E.; Slavin, S.; Kim, T.; Kersey, J.; Simmons, R.L.

    1982-10-01

    Twenty-two patients at high risk to reject renal allografts have been treated with fractionated total lymphoid irradiation (FTLI) prior to transplantation of primary (2), secondary (16) or tertiary (4) renal allografts. All patients undergoing retransplantation had rapidly rejected previous grafts. At 24 months following transplantation, 72% of grafts were functioning in the TLI group compared with a 38% graft function in an historical control group of recipients receiving secondary or tertiary grafts and treated with conventional immunosuppression. Important variables in determining success of transplantation following fractionated TLI include the dose of TLI, the interval from radiation to transplantation, and maintenance post-transplant immunosuppressive therapy. Optimal results were achieved with 2500 rads delivered in 100 rad fractions followed by transplantation within two weeks, and a tapering prednisone schedule and maintenance azathioprine post-transplantation. Seventeen patients had significant complications of the radiation treatment and there was one death, prior to transplantation, associated with pneumonitis. In vitro assessment of immune function demonstrated marked peripheral T cell depletion and loss of in vitro responsiveness to mitogen and allogeneic stimulation following FTLI. The administration of donor bone marrow at the time of transplantation did not produce chimerism. The results suggest that when properly utilized FTLI can produce effective adjunctive immunosuppression for clinical transplantation.

  19. Multiple MTS Assay as the Alternative Method to Determine Survival Fraction of the Irradiated HT-29 Colon Cancer Cells

    PubMed Central

    Arab-Bafrani, Zahra; Shahbazi-Gahrouei, Daryoush; Abbasian, Mahdi; Fesharaki, Mehrafarin

    2016-01-01

    A multiple colorimetric assay has been introduced to evaluate the proliferation and determination of survival fraction (SF) of irradiated cells. The estimation of SF based on the cell-growth curve information is the major advantage of this assay. In this study, the utility of multiple-MTS assay for the SF estimation of irradiated HT-29 colon cancer cells, which were plated before irradiation, was evaluated. The SF of HT-29 colon cancer cells under irradiation with 9 MV photon was estimated using multiple-MTS assay and colony assay. Finally, the correlation between two assays was evaluated. Results showed that there are no significant differences between the SF obtained by two assays at different radiation doses (P > 0.05), and the survival curves have quite similar trends. In conclusion, multiple MTS-assay can be a reliable method to determine the SF of irradiated colon cancer cells that plated before irradiation. PMID:27186539

  20. Absorbed dose calculations to blood and blood vessels for internally deposited radionuclides

    SciTech Connect

    Akabani, G. ); Poston, J.W. . Dept. of Nuclear Engineering)

    1991-05-01

    At present, absorbed dose calculations for radionuclides in the human circulatory system used relatively simple models and are restricted in their applications. To determine absorbed doses to the blood and to the surface of the blood vessel wall, EGS4 Monte Carlo calculations were performed. Absorbed doses were calculated for the blood and the blood vessel wall (lumen) for different blood vessels sizes. The radionuclides chosen for this study were those commonly used in nuclear medicine. No diffusion of the radionuclide into the blood vessel was assumed nor cross fire between vessel was assumed. Results are useful in assessing the dose in blood and blood vessel walls for different nuclear medicine procedures. 6 refs., 6 figs., 5 tabs.

  1. Absorbed dose calculations to blood and blood vessels for internally deposited radionuclides

    SciTech Connect

    Akabani, G.; Poston, J.W. Sr. )

    1991-05-01

    At present, absorbed dose calculations for radionuclides in the human circulatory system used relatively simple models and are restricted in their applications. To determine absorbed doses to the blood and to the surface of the blood vessel wall, EGS4 Monte Carlo calculations were performed. Absorbed doses were calculated for the blood and the blood vessel wall (lumen) for different blood vessels sizes. The radionuclides chosen for this study were those commonly used in nuclear medicine. No penetration of the radionuclide into the blood vessel was assumed nor was cross fire between the vessel assumed. The results are useful in assessing the dose to blood and blood vessel walls for different nuclear medicine procedures.

  2. Accidental embryo irradiation during barium enema examinations: An estimation of absorbed dose

    SciTech Connect

    Damilakis, J.; Perisinakis, K.; Grammatikakis, J.

    1996-04-01

    The purpose of this report is to investigate the possibility of an embryo to receive a dose of more than 10 cGy, the threshold of malformation induction in embryos reported by the International Commission on Radiological Protection, during barium enema examinations. Thermoluminescent dosimeters were place in a phantom to calculate the depth-to-skin conversion coefficient needed for dose estimation at the average embryo depth in patients. Barium enema examinations were performed in 20 women of childbearing age with diagnostic problems demanding longer fluoroscopy times. Doses at 6 cm, the average embryo depth, were determined by measurements at the patients` skin followed by dose calculation at the site of interest. The range of doses estimated at embryo depth for patients was 1.9 to 8.2 cGy. The dose always exceeded 5 cGy when fluoroscopy time was longer than 7 minutes. The dose at the embryo depth never exceeded 10 cGy. This study indicates that fluoroscopy time should not exceed 7 minutes in childbearing-age female patients undergoing barium enema examinations. 6 refs., 1 fig., 2 tabs.

  3. Re-irradiation with hypo-fractionated stereotactic robotic radiotherapy for salvage in adult patients with brainstem glioma

    PubMed Central

    Susheela, Sridhar P; Revannasiddaiah, Swaroop; Muzumder, Sandeep; Mallarajapatna, Govindarajan; Kallur, Kumar; Basavalingaiah, Ajaikumar S

    2013-01-01

    Purpose Brainstem glioma (BSG) is often treated with definitive irradiation. However, subsequent progression and death occur as a rule rather than the exception, after varying periods of control. The outlook of patients with post-irradiation progression is dismal, and most of these patients are treated with supportive care alone. Despite the obvious risks with an area as critical as the brainstem, it is a possibility to encounter situations wherein the patients (themselves or their associates) ask for re-irradiation, with the hope of a few extra months of life. The risk of radiation-induced brainstem toxicity may be justifiable under the strict assumption that the patients stand a chance of benefiting from re-irradiation but still may not live long enough to manifest brainstem toxicity. Methods Five adult BSG patients were treated with re-irradiation using robotic-arm stereotactic radiation therapy (SRT) between September 2009 and July 2012, primarily at the request of the concerned patient parties. Re-irradiation doses ranged from 16 to 25 Gray (Gy) delivered by robotic arm stereotactic irradiation in 2–5 fractions. Results Four out of five patients enjoyed a prolongation of survival in the order of months (three, five, six, and 14 months), which was very significant given that all patients had severe neurological compromise and poor performance status prior to re-irradiation. One patient has survived 36 months after re-irradiation and thus has lived long enough to manifest late radiation-induced brainstem toxicity. Conclusion Despite the obvious risks of brainstem toxicity associated with the use of re-irradiation for BSG, the use of fractionated stereotactic re-irradiation seems to offers prospects of additional periods of local control and augments duration of life. PMID:24171050

  4. Diversification of existing reference phantoms in nuclear medicine: Calculation of specific absorbed fractions for 21 mathematical phantoms and validation through dose estimates resulting from the administration of (18)F-FDG.

    PubMed

    Blaickner, Matthias; Kindl, Peter

    2008-12-01

    Current dose assessment in nuclear medicine patient studies relies on published S-values, which are, in turn, based on calculated specific absorbed fractions (SAFs) available for a limited number of anthro-pomorphic computational phantoms. In order to take the individual physiognomy of patients more into account, this study aimed to broaden the supply of phantoms and their respective SAFs. An ensemble of 21 mathematical phantoms was submitted to the Monte Carlo Code MCNP4c2 for the purpose of calculation of SAFs for annihilation radiation. These values were incorporated into an internal dose assessment following the Medical Internal Radiation Dose (MIRD) schema and relying on published biokinetic data for intravenous administration of (18)F-FDG. The results were compared with data from the ICRP, MIRD reports and concurrent calculations with OLINDA/EXM. A very good agreement with sources relying on the SAFs of Cristy and Eckerman (i.e., the ICRP and OLINDA/EXM) was observed, with the absorbed dose in lung being the only exception. In the case of dose to red marrow, the King Spiers factors were omitted in the three-factor approximation, which led to a precise accordance with the Cristy/Eckerman values. Summarizing, one can say that the coincidence with published data justifies the method chosen and demonstrates successfully the expansion of available reference phantoms for dose assessment in nuclear medicine. PMID:19111050

  5. Damage Thresholds and Morphology of the Front- and Back-Irradiated SiO2 Thin Films Containing Gold Nanoparticles as Artificial Absorbing Defects

    SciTech Connect

    Papernov, S.; Schmid, A.W.; Oliver, J.B.; Rigatti, A.L.

    2008-01-30

    Previous ultraviolet-pulsed, laser-damage studies using model thin films with gold nanoparticles as artificial absorbing defects revealed damage morphology in a form of submicrometer-scaled craters. It was also demonstrated that for defects smaller than 20 nm, crater formation is preceded by plasma-ball formation around absorbing defects. In this work an attempt is made to verify symmetry of the plasma ball by conducting film irradiation from the side of the air/film or substrate/film interfaces. In each case, crater-formation thresholds are derived and crater morphology is analyzed by means of atomic force microscopy.

  6. Benefits of online in vivo dosimetry for single-fraction total body irradiation

    SciTech Connect

    Eaton, David J.; Warry, Alison J.; Trimble, Rachel E.; Vilarino-Varela, Maria J.; Collis, Christopher H.

    2014-01-01

    Use of a patient test dose before single-fraction total body irradiation (TBI) allows review of in vivo dosimetry and modification of the main treatment setup. However, use of computed tomography (CT) planning and online in vivo dosimetry may reduce the need for this additional step. Patients were treated using a supine CT-planned extended source-to-surface distance (SSD) technique with lead compensators and bolus. In vivo dosimetry was performed using thermoluminescent dosimeters (TLDs) and diodes at 10 representative anatomical locations, for both a 0.1-Gy test dose and the treatment dose. In total, 28 patients were treated between April 2007 and July 2013, with changes made in 10 cases (36%) following test dose results. Overall, 98.1% of measured in vivo treatment doses were within 10% of the prescribed dose, compared with 97.0% of test dose readings. Changes made following the test dose could have been applied during the single-fraction treatment itself, assuming that the dose was delivered in subportions and online in vivo dosimetry was available for all clinically important anatomical sites. This alleviates the need for a test dose, saving considerable time and resources.

  7. Benefits of online in vivo dosimetry for single-fraction total body irradiation.

    PubMed

    Eaton, David J; Warry, Alison J; Trimble, Rachel E; Vilarino-Varela, Maria J; Collis, Christopher H

    2014-01-01

    Use of a patient test dose before single-fraction total body irradiation (TBI) allows review of in vivo dosimetry and modification of the main treatment setup. However, use of computed tomography (CT) planning and online in vivo dosimetry may reduce the need for this additional step. Patients were treated using a supine CT-planned extended source-to-surface distance (SSD) technique with lead compensators and bolus. In vivo dosimetry was performed using thermoluminescent dosimeters (TLDs) and diodes at 10 representative anatomical locations, for both a 0.1-Gy test dose and the treatment dose. In total, 28 patients were treated between April 2007 and July 2013, with changes made in 10 cases (36%) following test dose results. Overall, 98.1% of measured in vivo treatment doses were within 10% of the prescribed dose, compared with 97.0% of test dose readings. Changes made following the test dose could have been applied during the single-fraction treatment itself, assuming that the dose was delivered in subportions and online in vivo dosimetry was available for all clinically important anatomical sites. This alleviates the need for a test dose, saving considerable time and resources. PMID:25151596

  8. Irradiation-assisted stress corrosion cracking behavior of austenitic stainless steels applicable to LWR core internals.

    SciTech Connect

    Chung, H. M.; Shack, W. J.; Energy Technology

    2006-01-31

    This report summarizes work performed at Argonne National Laboratory on irradiation-assisted stress corrosion cracking (IASCC) of austenitic stainless steels that were irradiated in the Halden reactor in simulation of irradiation-induced degradation of boiling water reactor (BWR) core internal components. Slow-strain-rate tensile tests in BWR-like oxidizing water were conducted on 27 austenitic stainless steel alloys that were irradiated at 288 C in helium to 0.4, 1.3, and 3.0 dpa. Fractographic analysis was conducted to determine the fracture surface morphology. Microchemical analysis by Auger electron spectroscopy was performed on BWR neutron absorber tubes to characterize grain-boundary segregation of important elements under BWR conditions. At 0.4 and 1.4 dpa, transgranular fracture was mixed with intergranular fracture. At 3 dpa, transgranular cracking was negligible, and fracture surface was either dominantly intergranular, as in field-cracked core internals, or dominantly ductile or mixed. This behavior indicates that percent intergranular stress corrosion cracking determined at {approx}3 dpa is a good measure of IASCC susceptibility. At {approx}1.4 dpa, a beneficial effect of a high concentration of Si (0.8-1.5 wt.%) was observed. At {approx}3 dpa, however, such effect was obscured by a deleterious effect of S. Excellent resistance to IASCC was observed up to {approx}3 dpa for eight heats of Types 304, 316, and 348 steel that contain very low concentrations of S. Susceptibility of Types 304 and 316 steels that contain >0.003 wt.% S increased drastically. This indicates that a sulfur related critical phenomenon plays an important role in IASCC. A sulfur content of <0.002 wt.% is the primary material factor necessary to ensure good resistance to IASCC. However, for Types 304L and 316L steel and their high-purity counterparts, a sulfur content of <0.002 wt.% alone is not a sufficient condition to ensure good resistance to IASCC. This is in distinct contrast to

  9. Spinal Cord Tolerance to Single-Fraction Partial-Volume Irradiation: A Swine Model

    SciTech Connect

    Medin, Paul M.; Foster, Ryan D.; Kogel, Albert J. van der; Sayre, James W.; McBride, William H.; Solberg, Timothy D.

    2011-01-01

    Purpose: To determine the spinal cord tolerance to single-fraction, partial-volume irradiation in swine. Methods and Materials: A 5-cm-long cervical segment was irradiated in 38-47-week-old Yucatan minipigs using a dedicated, image-guided radiosurgery linear accelerator. The radiation was delivered to a cylindrical volume approximately 5 cm in length and 2 cm in diameter that was positioned lateral to the cervical spinal cord, resulting in a dose distribution with the 90%, 50%, and 10% isodose lines traversing the ipsilateral, central, and contralateral spinal cord, respectively. The dose was prescribed to the 90% isodose line. A total of 26 pigs were stratified into eight dose groups of 12-47 Gy. The mean maximum spinal cord dose was 16.9 {+-} 0.1, 18.9 {+-} 0.1, 21.0 {+-} 0.1, 23.0 {+-} 0.2, and 25.3 {+-} 0.3 Gy in the 16-, 18-, 20-, 22-, and 24-Gy dose groups, respectively. The mean percentage of spinal cord volumes receiving {>=}10 Gy for the same groups were 43% {+-} 3%, 48% {+-} 4%, 51% {+-} 2%, 57% {+-} 2%, and 59% {+-} 4%. The study endpoint was motor neurologic deficit determined by a change in gait during a 1-year follow-up period. Results: A steep dose-response curve was observed with a median effective dose for the maximum dose point of 20.0 Gy (95% confidence interval, 18.3-21.7). Excellent agreement was observed between the occurrence of neurologic change and the presence of histologic change. All the minipigs with motor deficits showed some degree of demyelination and focal white matter necrosis on the irradiated side, with relative sparing of the gray matter. The histologic findings were unremarkable in the minipigs with normal neurologic status. Conclusions: Our results have indicated that for a dose distribution with a steep lateral gradient, the pigs had a lower median effective dose for paralysis than has been observed in rats and more closely resembles that for rats, mice, and guinea pigs receiving uniform spinal cord irradiation.

  10. Dose Calculation Evolution for Internal Organ Irradiation in Humans

    NASA Astrophysics Data System (ADS)

    Jimenez V., Reina A.

    2007-10-01

    The International Commission of Radiation Units (ICRU) has established through the years, a discrimination system regarding the security levels on the prescription and administration of doses in radiation treatments (Radiotherapy, Brach therapy, Nuclear Medicine). The first level is concerned with the prescription and posterior assurance of dose administration to a point of interest (POI), commonly located at the geometrical center of the region to be treated. In this, the effects of radiation around that POI, is not a priority. The second level refers to the dose specifications in a particular plane inside the patient, mostly the middle plane of the lesion. The dose is calculated to all the structures in that plane regardless if they are tumor or healthy tissue. In this case, the dose is not represented by a point value, but by level curves called "isodoses" as in a topographic map, so you can assure the level of doses to this particular plane, but it also leave with no information about how this values go thru adjacent planes. This is why the third level is referred to the volumetrical description of doses so these isodoses construct now a volume (named "cloud") that give us better assurance about tissue irradiation around the volume of the lesion and its margin (sub clinical spread or microscopic illness). This work shows how this evolution has resulted, not only in healthy tissue protection improvement but in a rise of tumor control, quality of life, better treatment tolerance and minimum permanent secuelae.

  11. Dose Calculation Evolution for Internal Organ Irradiation in Humans

    SciTech Connect

    Jimenez V, Reina A.

    2007-10-26

    The International Commission of Radiation Units (ICRU) has established through the years, a discrimination system regarding the security levels on the prescription and administration of doses in radiation treatments (Radiotherapy, Brach therapy, Nuclear Medicine). The first level is concerned with the prescription and posterior assurance of dose administration to a point of interest (POI), commonly located at the geometrical center of the region to be treated. In this, the effects of radiation around that POI, is not a priority. The second level refers to the dose specifications in a particular plane inside the patient, mostly the middle plane of the lesion. The dose is calculated to all the structures in that plane regardless if they are tumor or healthy tissue. In this case, the dose is not represented by a point value, but by level curves called 'isodoses' as in a topographic map, so you can assure the level of doses to this particular plane, but it also leave with no information about how this values go thru adjacent planes. This is why the third level is referred to the volumetrical description of doses so these isodoses construct now a volume (named 'cloud') that give us better assurance about tissue irradiation around the volume of the lesion and its margin (sub clinical spread or microscopic illness). This work shows how this evolution has resulted, not only in healthy tissue protection improvement but in a rise of tumor control, quality of life, better treatment tolerance and minimum permanent secuelae.

  12. Radiosensitizing effect of misonidazole in acute and fractionated irradiation of a human osteosarcoma xenograft. [/sup 60/Co

    SciTech Connect

    Rofstad, E.K.; Brustad, T.

    1980-09-01

    The radiosensitizing effect of misonidazole (Ro-07-0582) in acute and fractionated irradiation of a human osteosarcoma grown in the athymic mutant nude mouse was studied. Tumor regrowth delay was used as a measure of response. The enhancement ratio of misonidazole was found to be 1.45 for an actue dose of 12.50 Gy and 1.25 for four fractions of 3.75 Gy, delivered over four consecutive days. It is concluded that the present osteosarcoma xenograft reoxygenated inadequately during the three day period which elapsed from the first to the fourth fraction of 3.75 Gy.

  13. Fractionated irradiation-induced EMT-like phenotype conferred radioresistance in esophageal squamous cell carcinoma

    PubMed Central

    Zhang, Hongfang; Luo, Honglei; Jiang, Zhenzhen; Yue, Jing; Hou, Qiang; Xie, Ruifei; Wu, Shixiu

    2016-01-01

    The efficacy of radiotherapy, one major treatment modality for esophageal squamous cell carcinoma (ESCC) is severely attenuated by radioresistance. Epithelial-to-mesenchymal transition (EMT) is a cellular process that determines therapy response and tumor progression. However, whether EMT is induced by ionizing radiation and involved in tumor radioresistance has been less studied in ESCC. Using multiple fractionated irradiation, the radioresistant esophageal squamous cancer cell line KYSE-150R had been established from its parental cell line KYSE-150. We found KYSE-150R displayed a significant EMT phenotype with an elongated spindle shape and down-regulated epithelial marker E-cadherin and up-regulated mesenchymal marker N-cadherin in comparison with KYSE-150. Furthermore, KYSE-150R also possessed some stemness-like properties characterized by density-dependent growth promotion and strong capability for sphere formation and tumorigenesis in NOD-SCID mice. Mechanical studies have revealed that WISP1, a secreted matricellular protein, is highly expressed in KYSE-150R and mediates EMT-associated radioresistance both in ESCC cells and in xenograft tumor models. Moreover, WISP1 has been demonstrated to be closely associated with the EMT phenotype observed in ESCC patients and to be an independent prognosis factor of ESCC patients treated with radiotherapy. Our study highlighted WISP1 as an attractive target to reverse EMT-associated radioresistance in ESCC and can be used as an independent prognostic factor of patients treated with radiotherapy. PMID:27125498

  14. Inhibiting the Aurora B Kinase Potently Suppresses Repopulation During Fractionated Irradiation of Human Lung Cancer Cell Lines

    SciTech Connect

    Sak, Ali; Stuschke, Martin; Groneberg, Michael; Kuebler, Dennis; Poettgen, Christoph; Eberhardt, Wilfried E.E.

    2012-10-01

    Purpose: The use of molecular-targeted agents during radiotherapy of non-small-cell lung cancer (NSCLC) is a promising strategy to inhibit repopulation, thereby improving therapeutic outcome. We assessed the combined effectiveness of inhibiting Aurora B kinase and irradiation on human NSCLC cell lines in vitro. Methods and Materials: NSCLC cell lines were exposed to concentrations of AZD1152-hydroxyquinazoline pyrazol anilide (AZD1152-HQPA) inhibiting colony formation by 50% (IC50{sub clone}) in combination with single dose irradiation or different fractionation schedules using multiple 2-Gy fractions per day up to total doses of 4-40 Gy. The total irradiation dose required to control growth of 50% of the plaque monolayers (TCD50) was determined. Apoptosis, G2/M progression, and polyploidization were also analyzed. Results: TCD50 values after single dose irradiation were similar for the H460 and H661 cell lines with 11.4 {+-} 0.2 Gy and 10.7 {+-} 0.3 Gy, respectively. Fractionated irradiation using 3 Multiplication-Sign 2 Gy/day, 2 Multiplication-Sign 2 Gy/day, and 1 Multiplication-Sign 2 Gy/day schedules significantly increased TCD50 values for both cell lines grown as plaque monolayers with increasing radiation treatment time. This could be explained by a repopulation effect per day that counteracts 75 {+-} 8% and 27 {+-} 6% of the effect of a 2-Gy fraction in H460 and H661 cells, respectively. AZD1152-HQPA treatment concomitant to radiotherapy significantly decreased the daily repopulation effect (H460: 28 {+-} 5%, H661: 10 {+-} 4% of a 2-Gy fraction per day). Treatment with IC50{sub clone} AZD1152-HPQA did not induce apoptosis, prolong radiation-induced G2 arrest, or delay cell cycle progression before the spindle check point. However, polyploidization was detected, especially in cell lines without functional p53. Conclusions: Inhibition of Aurora B kinase with low AZD1152-HQPA concentrations during irradiation of NSCLC cell lines affects repopulation during

  15. Effects of internal low-dose irradiation from 131I on gene expression in normal tissues in Balb/c mice

    PubMed Central

    2011-01-01

    Background The aim of this study was to investigate the global gene expression response of normal tissues following internal low absorbed dose irradiation of 131I. Methods Balb/c mice were intravenously injected with 13 to 260 kBq of 131I and euthanized 24 h after injection. Kidneys, liver, lungs, and spleen were surgically removed. The absorbed dose to the tissues was 0.1 to 9.7 mGy. Total RNA was extracted, and Illumina MouseRef-8 Whole-Genome Expression BeadChips (Illumina, Inc., San Diego, California, USA) were used to compare the gene expression of the irradiated tissues to that of non-irradiated controls. The Benjamini-Hochberg method was used to determine differentially expressed transcripts and control for false discovery rate. Only transcripts with a modulation of 1.5-fold or higher, either positively or negatively regulated, were included in the analysis. Results The number of transcripts affected ranged from 260 in the kidney cortex to 857 in the lungs. The majority of the affected transcripts were specific for the different absorbed doses delivered, and few transcripts were shared between the different tissues investigated. The response of the transcripts affected at all dose levels was generally found to be independent of dose, and only a few transcripts showed increasing or decreasing regulation with increasing absorbed dose. Few biological processes were affected at all absorbed dose levels studied or in all tissues studied. The types of biological processes affected were clearly tissue-dependent. Immune response was the only biological process affected in all tissues, and processes affected in more than three tissues were primarily associated with the response to stimuli and metabolism. Conclusion Despite the low absorbed doses delivered to the tissues investigated, a surprisingly strong response was observed. Affected biological processes were primarily associated with the normal function of the tissues, and only small deviations from the normal

  16. Evaluation of Beta-Absorbed Fractions in a Mouse Model for 90Y, 188Re, 166Ho, 149Pm, 64Cu, and 177Lu Radionuclides

    SciTech Connect

    Miller, William H.; Hartmann-Siantar, Christine; Fisher, Darrell R.; Descalle, Marie-Anne; Daly, Tom; Lehmann, Joerg; Lewis, Michael R.; Hoffman, Timothy J.; Smith, Jeff; Situ, Peter D.; Volkert, Wynn A.

    2005-08-01

    Several short-lived, high-energy beta emitters are being proposed as the radionuclide components for molecular-targeted potential cancer therapeutic agents. The laboratory mice used to determine the efficacy of these new agents have organs that are relatively small compared to the ranges of these high-energy particles. The dosimetry model developed by Hui et al. was extended to provide realistic beta-dose estimates for organs in mice that received therapeutic radiopharmaceuticals containing 90Y, 188Re, 166Ho, 149Pm, 64Cu, and 177 Lu. Major organs in this model included the liver, spleen, kidneys, lungs, heart, stomach, small and large bowel, thyroid, pancreas, bone, marrow, carcass, and a 0.025-g tumor. The study as reported in this paper verifies their results for 90Y and extends them by using their organ geometry factors combined with newly calculated organ self-absorbed fractions from PEREGRINE and MCNP. PEREGRINE and MCNP agree to within 8% for the worst-case organ with average differences (averaged over all organs) decreasing from 5% for 90Y to 1% for 177Lu. When used with typical biodistribution data, the three different models predict doses that are in agreement to within 5% for the worst-case organ. The beta-absorbed fractions and cross-organ-deposited energy provided in this paper can be used by researchers to predict mouse-organ doses and should contribute to an improved understanding of the relationship between dose and radiation toxicity in mouse models where use of these isotopes is favorable.

  17. Evaluation of beta-absorbed fractions in a mouse model for 90Y, 188Re, 166Ho, 149Pm, 64Cu, and 177Lu radionuclides.

    PubMed

    Miller, William H; Hartmann-Siantar, Christine; Fisher, Darrell; Descalle, Marie-Anne; Daly, Tom; Lehmann, Joerg; Lewis, Michael R; Hoffman, Timothy; Smith, Jeff; Situ, Peter D; Volkert, Wynn A

    2005-08-01

    Several short-lived, high-energy beta emitters are being proposed as the radionuclide components for molecular- targeted potential cancer therapeutic agents. The laboratory mice used to determine the efficacy of these new agents have organs that are relatively small compared to the ranges of these high-energy particles. The dosimetry model developed by Hui et al. was extended to provide realistic beta-dose estimates for organs in mice that received therapeutic radiopharmaceuticals containing (90)Y, (188)Re, (166)Ho, (149)Pm, (64)Cu, and (177)Lu. Major organs in this model included the liver, spleen, kidneys, lungs, heart, stomach, small and large bowel, thyroid, pancreas, bone, marrow, carcass, and a 0.025-g tumor. The study as reported in this paper verifies their results for (90)Y and extends them by using their organ geometry factors combined with newly calculated organ self-absorbed fractions from PEREGRINE and MCNP. PEREGRINE and MCNP agree to within 8% for the worst-case organ with average differences (averaged over all organs) decreasing from 5% for (90)Y to 1% for (177)Lu. When used with typical biodistribution data, the three different models predict doses that are in agreement to within 5% for the worst-case organ. The beta-absorbed fractions and cross-organ-deposited energy provided in this paper can be used by researchers to predict mouse-organ doses and should contribute to an improved understanding of the relationship between dose and radiation toxicity in mouse models where use of these isotopes is favorable. PMID:16114992

  18. Tuning algorithms for fractional order internal model controllers for time delay processes

    NASA Astrophysics Data System (ADS)

    Muresan, Cristina I.; Dutta, Abhishek; Dulf, Eva H.; Pinar, Zehra; Maxim, Anca; Ionescu, Clara M.

    2016-03-01

    This paper presents two tuning algorithms for fractional-order internal model control (IMC) controllers for time delay processes. The two tuning algorithms are based on two specific closed-loop control configurations: the IMC control structure and the Smith predictor structure. In the latter, the equivalency between IMC and Smith predictor control structures is used to tune a fractional-order IMC controller as the primary controller of the Smith predictor structure. Fractional-order IMC controllers are designed in both cases in order to enhance the closed-loop performance and robustness of classical integer order IMC controllers. The tuning procedures are exemplified for both single-input-single-output as well as multivariable processes, described by first-order and second-order transfer functions with time delays. Different numerical examples are provided, including a general multivariable time delay process. Integer order IMC controllers are designed in each case, as well as fractional-order IMC controllers. The simulation results show that the proposed fractional-order IMC controller ensures an increased robustness to modelling uncertainties. Experimental results are also provided, for the design of a multivariable fractional-order IMC controller in a Smith predictor structure for a quadruple-tank system.

  19. CMSAF products Cloud Fraction Coverage and Cloud Type used for solar global irradiance estimation

    NASA Astrophysics Data System (ADS)

    Badescu, Viorel; Dumitrescu, Alexandru

    2016-01-01

    Two products provided by the climate monitoring satellite application facility (CMSAF) are the instantaneous Cloud Fractional Coverage (iCFC) and the instantaneous Cloud Type (iCTY) products. Previous studies based on the iCFC product show that the simple solar radiation models belonging to the cloudiness index class n CFC = 0.1-1.0 have rRMSE values ranging between 68 and 71 %. The products iCFC and iCTY are used here to develop simple models providing hourly estimates for solar global irradiance. Measurements performed at five weather stations of Romania (South-Eastern Europe) are used. Two three-class characterizations of the state-of-the-sky, based on the iCTY product, are defined. In case of the first new sky state classification, which is roughly related with cloud altitude, the solar radiation models proposed here perform worst for the iCTY class 4-15, with rRMSE values ranging between 46 and 57 %. The spreading error of the simple models is lower than that of the MAGIC model for the iCTY classes 1-4 and 15-19, but larger for iCTY classes 4-15. In case of the second new sky state classification, which takes into account in a weighted manner the chance for the sun to be covered by different types of clouds, the solar radiation models proposed here perform worst for the cloudiness index class n CTY = 0.7-0.1, with rRMSE values ranging between 51 and 66 %. Therefore, the two new sky state classifications based on the iCTY product are useful in increasing the accuracy of solar radiation models.

  20. CMSAF products Cloud Fraction Coverage and Cloud Type used for solar global irradiance estimation

    NASA Astrophysics Data System (ADS)

    Badescu, Viorel; Dumitrescu, Alexandru

    2016-08-01

    Two products provided by the climate monitoring satellite application facility (CMSAF) are the instantaneous Cloud Fractional Coverage (iCFC) and the instantaneous Cloud Type (iCTY) products. Previous studies based on the iCFC product show that the simple solar radiation models belonging to the cloudiness index class n CFC = 0.1-1.0 have rRMSE values ranging between 68 and 71 %. The products iCFC and iCTY are used here to develop simple models providing hourly estimates for solar global irradiance. Measurements performed at five weather stations of Romania (South-Eastern Europe) are used. Two three-class characterizations of the state-of-the-sky, based on the iCTY product, are defined. In case of the first new sky state classification, which is roughly related with cloud altitude, the solar radiation models proposed here perform worst for the iCTY class 4-15, with rRMSE values ranging between 46 and 57 %. The spreading error of the simple models is lower than that of the MAGIC model for the iCTY classes 1-4 and 15-19, but larger for iCTY classes 4-15. In case of the second new sky state classification, which takes into account in a weighted manner the chance for the sun to be covered by different types of clouds, the solar radiation models proposed here perform worst for the cloudiness index class n CTY = 0.7-0.1, with rRMSE values ranging between 51 and 66 %. Therefore, the two new sky state classifications based on the iCTY product are useful in increasing the accuracy of solar radiation models.

  1. Total lymphoid irradiation in rat heart albgrafts: dose, fractionation, and combination with cyclosporin-A. [X-ray

    SciTech Connect

    Rynasiewicz, J.J.; Sutherland, D.E.R.; Kawahara, K.; Kim, T.; Najarian, J.S.

    1981-03-01

    The survival or organ allografts is prolonged in mice and rats treated with fractionated, high-dose total lymphoid irradiation (TLI). We have studied the effect of TLI, alone or in combination with donor bone marrow or pharmacologic immunosuppression (cyclosporin-A: CY-A), on the survival of heterotopic rat heart allografts. Specifically, we evaluated the generalized immunosuppressive effect of TLI as a function of accumulated dose and fractionation schedule. In addition, TLI and CY-A were used individually in schedules that by themselves gave only moderate graft prolongation and then subsequently in sequential combination.

  2. Photosynthesis, Growth, and Ultraviolet Irradiance Absorbance of Cucurbita pepo L. Leaves Exposed to Ultraviolet-B Radiation (280-315 nm) 1

    PubMed Central

    Sisson, William B.

    1981-01-01

    Net photosynthesis, growth, and ultraviolet (UV) radiation absorbance were determined for the first leaf of Cucurbita pepo L. exposed to two levels of UV-B irradiation and a UV-B radiation-free control treatment. Absorbance by extracted flavonoid pigments and other UV-B radiation-absorbing compounds from the first leaves increased with time and level of UV-B radiation impinging on leaf surfaces. Although absorbance of UV-B radiation by extracted pigments increased substantially, UV-B radiation attenuation apparently was insufficient to protect completely the photosynthetic apparatus or leaf growth processes. Leaf expansion was repressed by daily exposure to 1365 Joules per meter per day of biologically effective UV-B radiation but not by exposure to 660 Joules per meter per day. Photosynthesis measured through ontogenesis of the first leaf was depressed by both UV-B radiation treatments. Repression of photosynthesis by UV-B radiation was especially evident during the ontogenetic period of maximum photosynthetic activity. PMID:16661610

  3. Radiobiological basis of total body irradiation with different dose rate and fractionation: repair capacity of hemopoietic cells

    SciTech Connect

    Song, C.W.; Kim, T.H.; Khan, F.M.; Kersey, J.H.; Levitt, S.H.

    1981-12-01

    Total body irradiation (TBI) followed by bone marrow transplantation is being used in the treatment of malignant or non-malignant hemopoietic disorders. It has been believed that the ability of hemopoietic cells to repair sublethal radiation damage is negligible. Therefore, several schools of investigators suggested that TBI in a single exposure at extremely low dose rate (5 rad/min) over several hours, or in several fractions in 2-3 days, should yield a higher therapeutic gain, as compared with a single exposure at a high dose rate (26 rad/min). We reviewed the existing data in the literature, in particular, the response of hemopoietic cells to fractionated doses of irradiation and found that the repair capacity of both malignant and non-malignant hemopoietic cells might be greater than has been thought. It is concluded that we should not underestimate the ability of hemopoietic cells to repair sublethal radiation damage in using TBI.

  4. Radiobiological basis of total body irradiation with different dose rate and fractionation: repair capacity of hemopoietic cells

    SciTech Connect

    Song, C.W.; Kim, T.H.; Khan, F.M.; Kersey, J.H.; Levitt, S.H.

    1981-12-01

    Total body irradiation (TBI) followed by bone marrow transplantation is being used in the treatment of malignant or non-malignant hemopoietic disorders. It has been believed that the ability of hemopoietic cells to repair sublethal radiation damage is negligible. Therefore, several schools of investigators suggested that TBI in a single exposure at extremely low dose rate (5 rad/min) over several hours, or in several fractions in 2-3 days, should yield a higher therapeutic gain, as compared with a single exposure at a high dose rate (25 rad/min). We reviewed the existing data in the literature, in particular, the response of hemopoietic cells to fractionated doses of irradiation and found that the repair capacity of both malignant and non-malignant hemopoietic cells might be greater than has been thought. It is concluded that we should not underestimate the ability of hemopoietic cells to repair sublethal radiation damage in using TBI.

  5. A Conceptual Design of an Internal Injection Absorber of 8 GeV H-Injection into the Fermilab Main Injector

    SciTech Connect

    Johnson, D.E.; Chen, A.; Rakhno, I.; /Fermilab

    2007-06-01

    An 8 GeV superconducting linear accelerator (SCL) has been proposed as a single stage H{sup -} injector into the Main Injector (MI) synchrotron[1]. This would be the highest energy H{sup -} multi-turn injection system in the world. An injection absorber is required to absorb a few percent o the incoming beam on a regular pulse by pulse basis. The requirements and conceptual design of an internal absorber, capable of steady state 6.5 kW is discussed.

  6. A primary experience of conventional fractionated three-dimensional conformal partial breast irradiation for early-stage breast cancer

    PubMed Central

    LIAO, LINGXIA; HAN, GUANG; LI, YANPING; WANG, ZHAOHUA; LIU, DONG; PI, ZHENGCHAO

    2011-01-01

    Recently, a number of clinical trials assessing partial breast irradiation (PBI), in particular accelerated partial breast irradiation, have been conducted in patients with early-stage breast cancer after breast-conserving surgery (BCS) in Europe and the US. By contrast, PBI is rarely performed in Eastern countries. In general, there are many physiological differences between Eastern and Western populations, and whether PBI is suitable for Eastern populations remains uncertain. Moreover, PBI is still in the stage of clinical research, and numerous questions have yet to be resolved. Thus, we designed a PBI trial to explore its feasibility and effectiveness for Eastern patients. According to the study criteria, 12 patients were enrolled between June 2003 and March 2007. Using three-dimensional conformal partial breast irradiation, they received a conventional fraction of 2 Gy/fraction/day, 5 fractions/week, DT60 Gy. According to follow-up data collected in August 2010, the rates of local recurrence and distant metastasis were 0%. The most common adverse reactions included grade 2 radioactive erythema in 2 (17%) cases and pigment deposition in 10 (83%). The results revealed that the patients exhibited good local tumor control, with minor adverse reactions and satisfactory cosmetic results. More samples and long-term observations are required to further assess the validity and feasibility of PBI. PMID:22977539

  7. Decoloration and mineralization of reactive dyes using electron beam irradiation, Part I: Effect of the dye structure, concentration and absorbed dose (single, binary and ternary systems)

    NASA Astrophysics Data System (ADS)

    Vahdat, Ali; Bahrami, S. Hajir; Arami, M.; Bahjat, A.; Tabakh, F.; Khairkhah, M.

    2012-07-01

    In this study, three different reactive dyes (C.I. Reactive Red 4, C.I. Reactive Blue 2 and C.I. Reactive Yellow 4) and their blend solutions were irradiated with 10 MeV electron beam. Effect of absorbed dose, dye structure and primary solution concentrations on the pH value changes, degree of decoloration and chemical oxygen demand (COD) removal of solutions were investigated. Results show that this method is effective in decomposition and decoloration of the dyes solutions. This method can be applied in mineralization of wastewater containing different dyes.

  8. Absorbed dose of secondary neutrons from galactic cosmic rays inside the International Space Station.

    PubMed

    Getselev, I; Rumin, S; Sobolevsky, N; Ufimtsev, M; Podzolko, M

    2004-01-01

    In this paper, we present the results of Monte-Carlo simulations of the flux and energy spectra of neutrons generated as a result of galactic cosmic ray proton interactions with the material of International Space Station (ISS) inside Zvezda Service Module, the Airlock between Russian and USA segments and one of Russian Research Modules for a full configuration of ISS. Calculations were made for ISS orbit for the energy ranges <10 and >10 MeV for both maximum and minimum of solar activity. To test the accuracy of the calculations the same simulations were made for MIR orbital station and for CORONAS-I satellite and compared with the results of measurements. Calculated and measured fluxes are in reasonable agreement. PMID:15881787

  9. Tumor induction in mice following localized single or fractionated dose irradiation: differences in tumor histotype and genetic susceptibility based on dose scheduling

    PubMed Central

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

    2015-01-01

    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 C3Hf/Kam and C57BL/6J mice were locally irradiated to the right hindlimb with either single large doses between 10 and 70 Gray (Gy) or fractionated doses totaling 40 to 80 Gy delivered at 2 Gy/day fractions, 5 days/week, for 4 to 8 weeks. The mice were closely evaluated for tumor development in the irradiated field for 800 days following 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 following fractionated irradiation (16.4%) in comparison to single dose irradiation (36.1%). Sarcomas were the predominant post-irradiation 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 following single dose irradiation, however, significant differences in tumor susceptibilities following fractionated radiation were not observed. For both strains of mice, osteosarcomas and hemangiosarcomas were significantly more common following fractionated irradiation whereas fibrosarcomas and malignant fibrous histiocytomas were significantly more common following single dose irradiation. Conclusions This study investigated the tumorigenic effect of acute large doses in comparison to fractionated radiation in which both the dose and delivery schedule were similar to those used in clinical radiotherapy. Differences in tumor histotype following single dose or fractionated radiation exposures provides novel in vivo evidence for differences in tumor

  10. Effect of gamma irradiation on ethylene-octene copolymers

    NASA Astrophysics Data System (ADS)

    Li, Jiuqiang; Peng, Jing; Qiao, Jinliang; Jin, Dongbin; Wei, Genshuan

    2002-03-01

    Two ethylene-octene copolymers (POE) were irradiated with 60Co gamma radiation and influence of irradiation atmosphere, absorbed dose and heat treatment of samples on the crosslinking were studied. Thermal properties and crystalline morphology of non-irradiated and irradiated POE were determined by using differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXS), respectively. The Charlesby-Pinner equation was used to describe the relationship between absorbed dose and sol fraction. The gel fraction of irradiated POE was lower and decreased with the increase of octene content when irradiated in oxygen, compared to irradiation in nitrogen atmosphere. The gel fraction increased significantly with the increasing of absorbed dose for the two copolymers. Heat treatment of samples prohibited the crosslinking of irradiated POE. The DSC results indicated that a subtle change of thermal properties of POE was observed before and after gamma irradiation at low dose. No change was found from the WAXS spectra of non-irradiated and irradiated POE. For heat-treating samples, the Charlesby-Pinner equation can not fit perfectly with the relationship between the sol fraction and absorbed dose, but it fits well with the crosslinking reaction of POE pellets.

  11. Reduced-order model for laminar vortex-induced vibration of a rigid circular cylinder with an internal nonlinear absorber

    NASA Astrophysics Data System (ADS)

    Tumkur, Ravi Kumar R.; Domany, Elad; Gendelman, Oleg V.; Masud, Arif; Bergman, Lawrence A.; Vakakis, Alexander F.

    2013-07-01

    The nonlinear interaction of a laminar flow and a sprung rigid circular cylinder results in vortex-induced vibration (VIV) of the cylinder. Passive suppression of the VIV by attaching an internal nonlinear vibration absorber that acts, in essence, as a nonlinear energy sink (NES) to the cylinder has been observed in finite-element computations involving thousands of degrees of freedom (DOF). A single-DOF self-excited oscillator is developed to approximate the limit-cycle oscillation (LCO) of the cylinder undergoing VIV. This self-excited oscillator models the interaction of the flow and the cylinder. Then, a two-DOF reduced-order model for the system with the internal NES is constructed by coupling the single-DOF NES to the single-DOF self-excited oscillator. Hence, the complicated high-dimensional system of flow-cylinder-NES involving thousands of DOF is reduced to a two-DOF model. The two targeted energy transfer mechanisms responsible for passive VIV suppression that are observed in the finite-element computations are fully reproduced using the two-DOF reduced-order model. This reduction of the dynamics to an easily tractable low-dimensional reduced-order model facilitates the approximate analysis of the underlying dynamics. Moreover, the underlying assumptions of the order reduction, and the parameter ranges of validity of the reduced-order model are formulated and systematically studied.

  12. 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

  13. The AT1 receptor antagonist, L-158,809, prevents or ameliorates fractionated whole-brain irradiation-induced cognitive impairment

    PubMed Central

    Robbins, Mike E.; Payne, Valerie; Tommasi, Ellen; Diz, Debra I; Hsu, Fang-Chi; Brown, William R.; Wheeler, Kenneth T.; Olson, John; Zhao, Weiling

    2009-01-01

    Purpose We hypothesized that administration of the angiotensin type 1 (AT1) receptor antagonist, L-158,809, to young adult male rats would prevent or ameliorate fractionated whole-brain irradiation (WBI)-induced cognitive impairment. Methods and Materials Groups of 80 young adult male Fischer 344 × Brown Norway (F344×BN) rats, 12–14 weeks old, received either: i] fractionated WBI; 40 Gy of γ rays in 4 weeks, 2 fractions/week, ii] sham-irradiation; iii] WBI plus L-158,809 (20 mg/L drinking water) starting 3 days prior, during and for 14, 28, or 54 weeks post-irradiation; and iv] sham-irradiation plus L-158,809 for 14, 28, or 54 weeks post-irradiation. An additional group of rats (n = 20) received L-158,809 prior to, during, and for 5 weeks post-irradiation, after which they received normal drinking water up to 28 weeks post-irradiation Results Administration of L-158,809 prior to, during, and for 28 or 54 weeks after fractionated WBI prevented or ameliorated the radiation-induced cognitive impairment observed 26 and 52 weeks post-irradiation. Moreover, giving L-158,809 prior to, during, and for only 5 weeks post-irradiation ameliorated the significant cognitive impairment observed 26 weeks post-irradiation. These radiation-induced cognitive impairments occurred without any changes in brain metabolites or gross histologic changes assessed at 28 and 54 weeks post-irradiation, respectively. Conclusions Administering L-158,809 prior to, during, and after fractionated WBI can prevent or ameliorate the chronic, progressive, cognitive impairment observed in rats at 26 and 52 weeks post-irradiation. These findings offer the promise of improving the quality of life for brain tumor patients. PMID:19084353

  14. Effect of fractionated versus unfractionated total body irradiation on the growth of the BN acute myelocytic leukemia

    SciTech Connect

    Hagenbeek, A.; Martens, A.C.M.

    1981-08-01

    The efficacy of various total body irradiation (TBI) regimens prior to bone marrow transplantation was evaluated in a rat model for acute myelocytic leukemia (Dq = 85.1 cGy gamma ; N = 3.7). Using high dose rate gamma-irradiation (115 cGy/min), fractionated TBI with large total daily doses (400 to 600 cGy), either given as acute doses or as split doses at 8 hr intervals, was most effective. Split doses (2 fractions per day) offered no additional advantage. At the most, a 4 log leukemic cell kill was induced. No lethal toxicity was observed. Nine-hundred cGy flash TBI had a similar anti-tumor effect, but with this regimen almost half of the rats died from radiation-induced toxicity (lungs and gastro-intestinal tract). The results are explained in terms of differences between normal and leukemic cells as regards (a) repair of sublethal damage; and (b) repopulation. Low dose rate continuous gamma-irradiation (0.26 cGy/min) with total doses ranging from 900 to 2000 cGy was also quite effective. Maximally a 4 log cell kill was obtained. With 2000 cGy, 50% of the rats died from the gastro-intestinal tract-syndrome. In addition to the major role played by chemotherapy, TBI is mainly of importance in sterilizing the various sanctuaries in the body which contain leukemic cells anatomically resistant to most cytostatic agents.

  15. A review of irradiation effects on LWR core internal materials - neutron embrittlement.

    SciTech Connect

    Chopra, O. K.; Rao, A. S.

    2011-05-01

    Austenitic stainless steels (SSs) are used extensively as structural alloys in the internal components of light water reactor (LWR) pressure vessels because of their relatively high strength, ductility, and fracture toughness. However, exposure to neutron irradiation for extended periods not only changes the microstructure and microchemistry of these steels, but also degrades their fracture properties. The existing data on irradiated austenitic SSs are reviewed to determine the effects of key parameters such as material type and condition and irradiation temperature, dose, and dose rate on neutron embrittlement. Differences in the radiation-induced degradation of fracture properties between LWR and fast-reactor irradiations are also discussed. The results are used to (a) define a threshold fluence above which irradiation effects on fracture toughness of the material are significant, (b) evaluate the potential of neutron embrittlement under LWR operating conditions, and (c) assess the potential effects of voids on fracture toughness.

  16. A review of irradiation effects on LWR core internal materials - Neutron embrittlement

    NASA Astrophysics Data System (ADS)

    Chopra, O. K.; Rao, A. S.

    2011-05-01

    Austenitic stainless steels (SSs) are used extensively as structural alloys in the internal components of light water reactor (LWR) pressure vessels because of their relatively high strength, ductility, and fracture toughness. However, exposure to neutron irradiation for extended periods not only changes the microstructure and microchemistry of these steels, but also degrades their fracture properties. The existing data on irradiated austenitic SSs are reviewed to determine the effects of key parameters such as material type and condition and irradiation temperature, dose, and dose rate on neutron embrittlement. Differences in the radiation-induced degradation of fracture properties between LWR and fast-reactor irradiations are also discussed. The results are used to (a) define a threshold fluence above which irradiation effects on fracture toughness of the material are significant, (b) evaluate the potential of neutron embrittlement under LWR operating conditions, and (c) assess the potential effects of voids on fracture toughness.

  17. Toward absolute quantification of iron oxide nanoparticles as well as cell internalized fraction using multiparametric MRI

    PubMed Central

    Girard, O. M.; Ramirez, R.; McCarty, S.; Mattrey, R. F.

    2012-01-01

    Iron oxide nanoparticles (IONPs) are widely used as MR contrast agents because of their strong magnetic properties and broad range of applications. The contrast induced by IONPs typically depends on concentration, water accessibility, particle size, and heterogeneity of IONP distribution within the microenvironment. Although the latter could be a tool to assess local physiological effects at the molecular level, it renders IONP quantification from relaxation measurements challenging. This study aims to quantify IONP concentration using susceptibility measurements. In addition, further analysis of relaxation data is proposed to extract quantitative information about the IONP spatial distribution. Mesenchymal stem cells were labeled with IONPs and the IONP concentration measured by mass spectroscopy. MR relaxation parameters (T1, T2, T2*) as well as magnetic susceptibility of cylindrical samples containing serial dilutions of mixtures of free and cell-internalized IONPs were measured and correlated with IONP concentration. Unlike relaxation data, magnetic susceptibility was independent of whether IONPs were free or internalized, making it an excellent candidate for IONP quantification. Using IONP concentration derived from mass spectroscopy and measured relaxation times, free and internalized IONP fractions were accurately calculated. Magnetic susceptibility was shown to be a robust technique to measure IONP concentration in this preliminary study. Novel imaging based susceptibility mapping techniques could prove to be valuable tools to quantify IONP concentration directly by MRI, for samples of arbitrarily shape. Combined with relaxation time mapping techniques, especially T2 and T2*, this could be an efficient way to measure both IONP concentration and the internalized IONP fraction in vivo using MRI, to gain insight into tissue function and molecular imaging paradigms. PMID:22649047

  18. Raman line imaging for spatially and temporally resolved mole fraction measurements in internal combustion engines.

    PubMed

    Miles, P C

    1999-03-20

    An optical diagnostic system based on line imaging of Raman-scattered light has been developed to study the mixing processes in internal combustion engines. The system permits multipoint, single laser-shot measurements of CO(2), O(2), N(2), C(3)H(8), and H(2)O mole fractions with submillimeter spatial resolution. Selection of appropriate system hardware is discussed, as are subsequent data reduction and analysis procedures. Results are reported for data obtained at multiple crank angles and in two different engine flow fields. Measurements are made at 12 locations simultaneously, each location having measurement volume dimensions of 0.5 mm x 0.5 mm x 0.9 mm. The data are analyzed to obtain statistics of species mole fractions: mean, rms, histograms, and both spatial and cross-species covariance functions. The covariance functions are used to quantify the accuracy of the measured rms mole fraction fluctuations, to determine the integral length scales of the mixture inhomogeneities, and to quantify the cycle-to-cycle fluctuations in bulk mixture composition under well-mixed conditions. PMID:18305796

  19. Correlation functions for the fractional generalized Langevin equation in the presence of internal and external noise

    SciTech Connect

    Sandev, Trifce; Metzler, Ralf; Department of Physics, Tampere University of Technology, FI-33101 Tampere ; Tomovski, Živorad

    2014-02-15

    We study generalized fractional Langevin equations in the presence of a harmonic potential. General expressions for the mean velocity and particle displacement, the mean squared displacement, position and velocity correlation functions, as well as normalized displacement correlation function are derived. We report exact results for the cases of internal and external friction, that is, when the driving noise is either internal and thus the fluctuation-dissipation relation is fulfilled or when the noise is external. The asymptotic behavior of the generalized stochastic oscillator is investigated, and the case of high viscous damping (overdamped limit) is considered. Additional behaviors of the normalized displacement correlation functions different from those for the regular damped harmonic oscillator are observed. In addition, the cases of a constant external force and the force free case are obtained. The validity of the generalized Einstein relation for this process is discussed. The considered fractional generalized Langevin equation may be used to model anomalous diffusive processes including single file-type diffusion.

  20. Influence of serotonin on fraction of lesions in DNA induced by ultraviolet light and roentgen irradiation

    SciTech Connect

    Ivanova, E.V.; Fraikin, G.Ya.

    1986-02-20

    The influence of serotonin on the yield of thymine dimers and rupture of the N-glycoside bond (the yield of thymine in DNA irradiated with ultraviolet light and roentgen irradiation) was studied by means of two-dimensional thin-layer chromatography. It was found that serotonin bound to DNA decreases the formation of UV-induced thymine dimers, but has no effect on the number of breaks in the N-glycoside bond in thymidine residues induced by roentgen irradiation. The data obtained are discussed in terms of the question of the mechanisms of the protective effect of serotonin in the photoprotection of yeast cells against the lethal action of UV- and roentgen radiation.

  1. A 3D Monte Carlo Method for Estimation of Patient-specific Internal Organs Absorbed Dose for (99m)Tc-hynic-Tyr(3)-octreotide Imaging.

    PubMed

    Momennezhad, Mehdi; Nasseri, Shahrokh; Zakavi, Seyed Rasoul; Parach, Ali Asghar; Ghorbani, Mahdi; Asl, Ruhollah Ghahraman

    2016-01-01

    Single-photon emission computed tomography (SPECT)-based tracers are easily available and more widely used than positron emission tomography (PET)-based tracers, and SPECT imaging still remains the most prevalent nuclear medicine imaging modality worldwide. The aim of this study is to implement an image-based Monte Carlo method for patient-specific three-dimensional (3D) absorbed dose calculation in patients after injection of (99m)Tc-hydrazinonicotinamide (hynic)-Tyr(3)-octreotide as a SPECT radiotracer. (99m)Tc patient-specific S values and the absorbed doses were calculated with GATE code for each source-target organ pair in four patients who were imaged for suspected neuroendocrine tumors. Each patient underwent multiple whole-body planar scans as well as SPECT imaging over a period of 1-24 h after intravenous injection of (99m)hynic-Tyr(3)-octreotide. The patient-specific S values calculated by GATE Monte Carlo code and the corresponding S values obtained by MIRDOSE program differed within 4.3% on an average for self-irradiation, and differed within 69.6% on an average for cross-irradiation. However, the agreement between total organ doses calculated by GATE code and MIRDOSE program for all patients was reasonably well (percentage difference was about 4.6% on an average). Normal and tumor absorbed doses calculated with GATE were slightly higher than those calculated with MIRDOSE program. The average ratio of GATE absorbed doses to MIRDOSE was 1.07 ± 0.11 (ranging from 0.94 to 1.36). According to the results, it is proposed that when cross-organ irradiation is dominant, a comprehensive approach such as GATE Monte Carlo dosimetry be used since it provides more reliable dosimetric results. PMID:27134562

  2. A 3D Monte Carlo Method for Estimation of Patient-specific Internal Organs Absorbed Dose for 99mTc-hynic-Tyr3-octreotide Imaging

    PubMed Central

    Momennezhad, Mehdi; Nasseri, Shahrokh; Zakavi, Seyed Rasoul; Parach, Ali Asghar; Ghorbani, Mahdi; Asl, Ruhollah Ghahraman

    2016-01-01

    Single-photon emission computed tomography (SPECT)-based tracers are easily available and more widely used than positron emission tomography (PET)-based tracers, and SPECT imaging still remains the most prevalent nuclear medicine imaging modality worldwide. The aim of this study is to implement an image-based Monte Carlo method for patient-specific three-dimensional (3D) absorbed dose calculation in patients after injection of 99mTc-hydrazinonicotinamide (hynic)-Tyr3-octreotide as a SPECT radiotracer. 99mTc patient-specific S values and the absorbed doses were calculated with GATE code for each source-target organ pair in four patients who were imaged for suspected neuroendocrine tumors. Each patient underwent multiple whole-body planar scans as well as SPECT imaging over a period of 1-24 h after intravenous injection of 99mhynic-Tyr3-octreotide. The patient-specific S values calculated by GATE Monte Carlo code and the corresponding S values obtained by MIRDOSE program differed within 4.3% on an average for self-irradiation, and differed within 69.6% on an average for cross-irradiation. However, the agreement between total organ doses calculated by GATE code and MIRDOSE program for all patients was reasonably well (percentage difference was about 4.6% on an average). Normal and tumor absorbed doses calculated with GATE were slightly higher than those calculated with MIRDOSE program. The average ratio of GATE absorbed doses to MIRDOSE was 1.07 ± 0.11 (ranging from 0.94 to 1.36). According to the results, it is proposed that when cross-organ irradiation is dominant, a comprehensive approach such as GATE Monte Carlo dosimetry be used since it provides more reliable dosimetric results. PMID:27134562

  3. Phototropism of Arabidopsis thaliana in microgravity and fractional gravity on the International Space Station.

    PubMed

    Kiss, John Z; Millar, Katherine D L; Edelmann, Richard E

    2012-08-01

    While there is a great deal of knowledge regarding plant growth and development in microgravity aboard orbiting spacecraft, there is little information available about these parameters in reduced or fractional gravity conditions (less than the nominal 1g on Earth). Thus, in these experiments using the European Modular Cultivation System on the International Space Station, we studied the interaction between phototropism and gravitropism in the WT and mutants of phytochrome A and B of Arabidopis thaliana. Fractional gravity and the 1 g control were provided by centrifuges in the spaceflight hardware, and unidirectional red and blue illumination followed a white light growth period in the time line of the space experiments. The existence of red-light-based positive phototropism in hypocotyls of seedlings that is mediated by phytochrome was confirmed in these microgravity experiments. Fractional gravity studies showed an attenuation of red-light-based phototropism in both roots and hypocotyls of seedlings occurring due to gravitational accelerations ranging from 0.l to 0.3 g. In contrast, blue-light negative phototropism in roots, which was enhanced in microgravity compared with the 1g control, showed a significant attenuation at 0.3 g. In addition, our studies suggest that the well-known red-light enhancement of blue-light-induced phototropism in hypocotyls is likely due to an indirect effect by the attenuation of gravitropism. However, red-light enhancement of root blue-light-based phototropism may occur via a more direct effect on the phototropism system itself, most likely through the phytochrome photoreceptors. To our knowledge, these experiments represent the first to examine the behavior of flowering plants in fractional or reduced gravity conditions. PMID:22481136

  4. Cycloheximide and disulfoton are positive in the photoclastogencity assay but do not absorb UV irradiation: another example of pseudophotoclastogenicity?

    PubMed

    Lynch, Anthony M; Robinson, Sharon A; Wilcox, Phil; Smith, Mark D; Kleinman, Mark; Jiang, Kaina; Rees, Robert W

    2008-03-01

    There is considerable concern regarding the biological plausibility of the response of certain chemicals in the in vitro photoclastogenicity assay, suggesting that this assay is oversensitive and lacks specificity. To explore this further, four coded compounds (aminotriazole, propantheline bromide, cycloheximide and disulfoton) were evaluated for their potential response in a photoclastogenicity assay in cultured Chinese hamster ovary (CHO) cells. None of the four compounds were shown to absorb ultraviolet radiation (UVR) or visible light in the 290- to 700-nm region of the electromagnetic spectrum. A fifth coded compound, tetracycline, which absorbs UVR, was also tested as this has previously been shown to be phototoxic in vitro (3T3-NRU assay) and is cytotoxic, but not genotoxic, at high concentrations in standard 'dark' genotoxicity assays in mammalian cells. The results showed that cycloheximide, disulfoton and tetracycline were clastogenic in CHO cells following UVR exposure (solar-simulated light at 700 mJ/cm(2)) but not in the absence of UVR. Aminotriazole and propantheline were negative in the presence and absence of UVR exposure. Follow-up testing showed that neither cycloheximide nor disulfoton was positive in the 3T3-NRU assay, the standard in vitro regulatory test for phototoxicity, a result consistent with their inability to absorb UVR. These data suggest that both cycloheximide and disulfoton are pseudophotoclastogens, like zinc oxide. Together, these data question the specificity of the in vitro photoclastogencity assay in CHO cells and raises further concern regarding its use for the assessment of chemical photosafety for regulatory purposes. At the very least, a review of the current guidance documents for the photosafety evaluation of pharmaceuticals and cosmetics should be undertaken urgently. PMID:18227081

  5. First international comparison of primary absorbed dose to water standards in the medium-energy X-ray range

    NASA Astrophysics Data System (ADS)

    Büermann, Ludwig; Guerra, Antonio Stefano; Pimpinella, Maria; Pinto, Massimo; de Pooter, Jacco; de Prez, Leon; Jansen, Bartel; Denoziere, Marc; Rapp, Benjamin

    2016-01-01

    This report presents the results of the first international comparison of primary measurement standards of absorbed dose to water for the medium-energy X-ray range. Three of the participants (VSL, PTB, LNE-LNHB) used their existing water calorimeter based standards and one participant (ENEA) recently developed a new standard based on a water-graphite calorimeter. The participants calibrated three transfer chambers of the same type in terms of absorbed dose to water (NDw) and in addition in terms of air kerma (NK) using the CCRI radiation qualities in the range 100 kV to 250 kV. The additional NK values were intended to be used for a physical analysis of the ratios NDw/NK. All participants had previously participated in the BIPM.RI(I)-K3 key comparison of air kerma standards. Ratios of pairs of NMI's NK results of the current comparison were found to be consistent with the corresponding key comparison results within the expanded uncertainties of 0.6 % - 1 %. The NDw results were analysed in terms of the degrees of equivalence with the comparison reference values which were calculated for each beam quality as the weighted means of all results. The participant's results were consistent with the reference value within the expanded uncertainties. However, these expanded uncertainties varied significantly and ranged between about 1-1.8 % for the water calorimeter based standards and were estimated at 3.7 % for the water-graphite calorimeter. It was shown previously that the ratios NDw/NK for the type of ionization chamber used as transfer chamber in this comparison were very close (within less than 1 %) to the calculated values of (bar muen/ρ)w,ad, the mean values of the water-to-air ratio of the mass-energy-absorption coefficients at the depth d in water. Some of the participant's results deviated significantly from the expected behavior. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of

  6. Dosimetry of single fraction high dose total body irradiation as measured by thermoluminescent dosimeters

    SciTech Connect

    Liu, J.C.; Bacza, E.T.; Findley, D.O.; Forell, B.W.

    1983-09-01

    Eighty-five patients with acute myelogenous or acute lymphoblastic leukemia were treated at the Cit of Hope National Medicine Center with chemotherapy, total body irradiation, and bone marrow transplant. The average mid-line dose to these patients was 1002 rad with a uniformity of 8%.

  7. Late Toxicity of a Novel Allogeneic Stem Cell Transplant Using Single Fraction Total Body Irradiation for Hematologic Malignancies in Children

    PubMed Central

    Ngwube, Alexander I.; Shenoy, Shalini; Druley, Todd E.; Hayashi, Robert J.

    2015-01-01

    Single fraction total body irradiation (SFTBI) as part of a myeloablative preparative regimen in allogeneic hematopoietic stem cell transplantation (HSCT) for hematopoietic malignancies was shown to have similar survival compared with fractionated total body irradiation (FTBI)-containing regimens, with less acute toxicity. The objective of this study was to determine long-term toxicity >2 years following SFTBI-based HSCT. Twenty-one patients were evaluated at a median follow-up of 6.8 years. Thyroid dysfunction was found in 21% of patients, 1 of whom (5.2%) was symptomatic; 23% had gonadal failure; 50% of patients with growth potential had linear growth disturbance; 27% had mild to moderate pulmonary disease; and 25% had cataracts. Intelligence quotient was stable. cGVHD was present in 28%, and 4 patients (19%) were on immune suppression 2 years posttransplant. Overall survival subsequent to 2 years posttransplant was 76% in this cohort of patients. No secondary malignancies were observed. In conclusion, the toxicities of SFTBI occurred at similar or reduced frequency compared with FTBI. SFTBI should be considered for patients who may benefit from a radiation-containing HSCT preparative regimen. PMID:25333837

  8. Release of monocyte migration signals by breast cancer cell lines after ablative and fractionated γ-irradiation

    PubMed Central

    2014-01-01

    Background Radiotherapy, administered in fractionated as well as ablative settings, is an essential treatment component for breast cancer. Besides the direct tumor cell death inducing effects, there is growing evidence that immune mechanisms contribute - at least in part - to its therapeutic success. The present study was designed to characterize the type and the extent of cell death induced by fractionated and ablative radiotherapy as well as its impact on the release of monocyte migration stimulating factors by dying breast cancer cells. Methods Cell death and senescence assays were employed to characterize the response of a panel of breast cancer cell lines with different receptor and p53 status towards γ-irradiation applied in a fractionated (daily doses of 2 Gy) or ablative setting (single dose of 20 Gy). Cell-free culture supernatants were examined for their monocyte migration stimulating potential in transwell migration and 2D chemotaxis/chemokinesis assays. Irradiation-induced transcriptional responses were analyzed by qRT-PCR, and CD39 surface expression was measured by flow cytometry. Results Fast proliferating, hormone receptor negative breast cancer cell lines with defective p53 predominantly underwent primary necrosis in response to γ-irradiation when applied at a single, ablative dose of 20 Gy, whereas hormone receptor positive, p53 wildtype cells revealed a combination of apoptosis, primary, and secondary (post-apoptotic) necrosis. During necrosis the dying tumor cells released apyrase-sensitive nucleotides, which effectively stimulated monocyte migration and chemokinesis. In hormone receptor positive cells with functional p53 this was hampered by irradiation-induced surface expression of the ectonucleotidase CD39. Conclusions Our study shows that ablative radiotherapy potently induces necrosis in fast proliferating, hormone receptor negative breast cancer cell lines with mutant p53, which in turn release monocyte migration and chemokinesis

  9. Analysis of Phosphorus in Soil Humic Acid Fractions by Enzymatic Hydrolysis and Ultraviolet Irradiation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Humic acid is an important soil component which influences chemical, biological, and physical soil properties. In this study, we investigated lability of phosphorus (P) in the mobile humic acid (MHA) and calcium humate (CaHA) fractions of four soils by orthophosphate-releasing enzymatic hydrolysis a...

  10. Comparison of Radiation-Induced Bystander Effect in QU-DB Cells after Acute and Fractionated Irradiation: An In Vitro Study

    PubMed Central

    Soleymanifard, Shokouhozaman; Bahreyni Toossi, Mohammad Taghi; Kamran Samani, Roghayeh; Mohebbi, Shokoufeh

    2016-01-01

    Objective Radiation effects induced in non-irradiated cells are termed radiation-induced bystander effects (RIBE). The present study intends to examine the RIBE response of QU-DB bystander cells to first, second and third radiation fractions and compare their cumulative outcome with an equal, single acute dose. Materials and Methods This experimental study irradiated three groups of target cells for one, two and three times with60Co gamma rays. One hour after irradiation, we transferred their culture media to non-irradiated (bystander) cells. We used the cytokinesis block micronucleus assay to evaluate RIBE response in the bystander cells. The numbers of micronuclei generated in bystander cells were determined. Results RIBE response to single acute doses increased up to 4 Gy, then decreased, and finally at the 8 Gy dose disappeared. The second and third fractions induced RIBE in bystander cells, except when RIBE reached to the maximum level at the first fraction. We split the 4 Gy acute dose into two fractions, which decreased the RIBE response. However, fractionation of 6 Gy (into two fractions of 3 Gy or three fractions of 2 Gy) had no effect on RIBE response. When we split the 8 Gy acute dose into two fractions we observed RIBE, which had disappeared following the single 8 Gy dose. Conclusion The impact of dose fractionation on RIBE induced in QU-DB cells de- pended on the RIBE dose-response relationship. Where RIBE increased proportion- ally with the dose, fractionation reduced the RIBE response. In contrast, at high dos- es where RIBE decreased proportionally with the dose, fractionation either did not change RIBE (at 6 Gy) or increased it (at 8 Gy). PMID:27602316

  11. Effects of mixing-induced irradiance fluctuations on nitrogen uptake in size-fractionated coastal phytoplankton communities

    NASA Astrophysics Data System (ADS)

    Maguer, Jean-François; L'Helguen, Stéphane; Waeles, Matthieu

    2015-03-01

    In coastal waters subjected to strong tidal forcing, phytoplankton populations are exposed to highly variable light regimes. To grow under such fluctuating light environments, phytoplankton adjust their physiological properties. Here, we investigated nitrogen (N) uptake patterns in the western English Channel to determine whether phytoplankton modify their physiological processes involved in N uptake in response to changing irradiance conditions induced by spring-neap tidal cycles. Nitrate (NO3-) and ammonium (NH4+) uptake kinetics as a function of irradiance (VN-E curves) were assessed using 15N tracer techniques on two size fractions (<10 and >10 μm) of phytoplankton collected at 50% and 1% of surface irradiance during two spring-neap tidal cycles. Overall, the results showed that both small and large phytoplankton, whatever their vertical position in the water column, increased their maximum uptake capacity and their light utilization efficiency for the two N substrates following the decrease in vertical mixing intensity. Moreover, the improvement of irradiance conditions at neap tides was of greater benefit for the larger cells than for the smaller ones and was more favorable for NO3- uptake than for NH4+ uptake. These findings show that the light regime fluctuation resulting from the relaxation of tidal mixing during spring-neap tidal cycle leads to profound physiological adjustments of N uptake processes in phytoplankton communities. They suggest that the changes in NO3- uptake by large phytoplankton associated with the fortnightly spring-neap tidal cycle can account for most of the deviation in background productivity in the western English Channel which is based on NH4+ and is dominated by small cells. The dynamic light regime inherent to macrotidal coastal ecosystems could therefore determine, to a large extent, the importance of new vs. regenerated production as well as the size structure of the phytoplankton community.

  12. Elective Lymph Node Irradiation With Intensity-Modulated Radiotherapy: Is Conventional Dose Fractionation Necessary?

    SciTech Connect

    Bedi, Meena; Firat, Selim; Semenenko, Vladimir A.; Schultz, Christopher; Tripp, Patrick; Byhardt, Roger; Wang, Dian

    2012-05-01

    Purpose: Intensity-modulated radiation therapy (IMRT) is the standard of care for head-and-neck cancer (HNC). We treated patients with HNC by delivering either a moderate hypofractionation (MHF) schedule (66 Gy at 2.2 Gy per fraction to the gross tumor [primary and nodal]) with standard dose fractionation (54-60 Gy at 1.8-2.0 Gy per fraction) to the elective neck lymphatics or a conventional dose and fractionation (CDF) schedule (70 Gy at 2.0 Gy per fraction) to the gross tumor (primary and nodal) with reduced dose to the elective neck lymphatics. We analyzed these two cohorts for treatment outcomes. Methods and Materials: Between November 2001 and February 2009, 89 patients with primary carcinomas of the oral cavity, larynx, oropharynx, hypopharynx, and nasopharynx received definitive IMRT with or without concurrent chemotherapy. Twenty patients were treated using the MHF schedule, while 69 patients were treated with the CDF schedule. Patient characteristics and dosimetry plans were reviewed. Patterns of failure including local recurrence (LR), regional recurrence (RR), distant metastasis (DM), disease-free survival (DFS), overall survival (OS), and toxicities, including rate of feeding tube placement and percentage of weight loss, were reviewed and analyzed. Results: Median follow-up was 31.2 months. Thirty-five percent of patients in the MHF cohort and 77% of patients in the CDF cohort received chemotherapy. No RR was observed in either cohort. OS, DFS, LR, and DM rates for the entire group at 2 years were 89.3%, 81.4%, 7.1%, and 9.4%, respectively. Subgroup analysis showed no significant differences in OS (p = 0.595), DFS (p = 0.863), LR (p = 0.833), or DM (p = 0.917) between these two cohorts. Similarly, no significant differences were observed in rates of feeding tube placement and percentages of weight loss. Conclusions: Similar treatment outcomes were observed for MHF and CDF cohorts. A dose of 50 Gy at 1.43 Gy per fraction may be sufficient to electively

  13. Fractionation of 50kGy electron beam irradiation: effects on biomechanics of human flexor digitorum superficialis tendons treated with ascorbate.

    PubMed

    Wei, Wei; Liu, Yujie; Yang, Xu; Tian, Shaoqi; Liu, Chao; Zhang, Yang; Xu, Zhaoning; Hu, Baiqiang; Tian, Zhen; Sun, Kang

    2013-02-22

    The electron beam (Ebeam) irradiation has begun to be considered as an efficient alternative to gamma irradiation in the sterilization of allografts in the reconstruction of anterior cruciate ligament. The purpose of this study was to evaluate the biomechanical properties of human tendons after exposure to electron beam and free radical scavenger ascorbate. Forty human flexor digitorum superficialis tendons were prepared from five fresh cadavers and divided randomly into four groups: A, fresh (0kGy); B, 50kGy Ebeam irradiation; C, fractionated 50kGy Ebeam irradiation; D, fractionated 50kGy Ebeam on ascorbate-treated tendons. The fractionation of 50kGy was achieved by repeated irradiation of 2.5kGy for 20 repetitions. Biomechanical properties were analyzed during load-to-failure testing. The fresh tendons were found to be significant different in ultimate load, ultimate elongation relative to tendons in group B. Statistical differences were found between group B and C in ultimate load. No differences were detected between group A and C in all the parameters. Compare tendons in group C and D, significant differences were found in ultimate load and ultimate stress. It is recommended that fractionated 50kGy electron beam irradiation and free radical scavenger ascorbate should be applied in the sterilization of allografts tendons. PMID:23261247

  14. Improving external beam radiotherapy by combination with internal irradiation

    PubMed Central

    Koi, L; Zöphel, K; Sihver, W; Kotzerke, J; Baumann, M; Krause, M

    2015-01-01

    The efficacy of external beam radiotherapy (EBRT) is dose dependent, but the dose that can be applied to solid tumour lesions is limited by the sensitivity of the surrounding tissue. The combination of EBRT with systemically applied radioimmunotherapy (RIT) is a promising approach to increase efficacy of radiotherapy. Toxicities of both treatment modalities of this combination of internal and external radiotherapy (CIERT) are not additive, as different organs at risk are in target. However, advantages of both single treatments are combined, for example, precise high dose delivery to the bulk tumour via standard EBRT, which can be increased by addition of RIT, and potential targeting of micrometastases by RIT. Eventually, theragnostic radionuclide pairs can be used to predict uptake of the radiotherapeutic drug prior to and during therapy and find individual patients who may benefit from this treatment. This review aims to highlight the outcome of pre-clinical studies on CIERT and resultant questions for translation into the clinic. Few clinical data are available until now and reasons as well as challenges for clinical implementation are discussed. PMID:25782328

  15. The 3D plant canopy radiative transfer analysis in an Alaskan black spruce forest: the characteristics of fraction of absorbed photosynthetically active radiation in the heterogeneous landscape

    NASA Astrophysics Data System (ADS)

    Kobayashi, H.; Suzuki, R.; Nagai, S.; Nakai, T.; Kim, Y.

    2012-12-01

    Over the last couple of decades, the three dimensional plant canopy radiative transfer models have been developed, improved and used for the retrievals of biophysical variables of vegetative surface. Fraction of absorbed photosynthetically active radiation (FAPAR) by plant canopy, a similar variable to heating rate in the atmosphere, is one of the important biophysical variables to infer the terrestrial plant canopy photosynthesis. FAPAR can be estimated by the radiative transfer model inversion or the empirical relationships between FAPAR and vegetation indices such as normalized difference vegetation index (NDVI). To date, some global FAPAR products are publicly available. These products are estimated from the moderate resolution satellites such as MODIS and SPOT-VEGETATION. One may apply the similar FAPAR algorithms to higher spatial resolution satellites if the ecosystem structures are horizontally homogeneous, which means that the adjacent satellite pixels have a similar spectral properties. If the vegetation surface is highly heterogeneous, "domain average FAPAR", which assumes no net horizontal radiation fluxes, can be unrealistically high (more than 1). In this presentation, we analyzed the characteristics of FAPAR in a heterogeneous landscape. As a case study, we selected our study site in a sparse black spruce forest in Alaska. We conducted the field campaigns to measure forest structural and optical properties that are used in the radiative transfer simulation. We used a 3D radiative transfer, FLiES (Kobayashi, H. and H. Iwabuchi (2008), A coupled 1-D atmosphere and 3-D canopy radiative transfer model for canopy reflectance, light environment, and photosynthesis simulation in a heterogeneous landscape, Remote Sensing of Environment, 112, 173-185) to create a high resolution simulated spectral reflectance and FAPAR images over the course of the growing season. From the analysis, we show (1) FAPAR with no net horizontal fluxes assumption can be higher than

  16. Effect of ultrasound irradiation on bacterial internalization and bacteria-mediated gene transfer to cancer cells.

    PubMed

    Ninomiya, Kazuaki; Yamada, Ryuji; Meisaku, Hitomi; Shimizu, Nobuaki

    2014-05-01

    The present study demonstrates that ultrasound irradiation can facilitate bacteria-mediated gene delivery (bactofection). Escherichia coli modified with avidin were employed as a vehicle for delivery of the green fluorescent protein (GFP) gene, a model heterologous gene, into the breast cancer cell line MCF-7. Avidin-mediated binding of E. coli to MCF-7 cells enhanced the internalization of E. coli by approximately 17%, irrespective of the use of ultrasound irradiation. Furthermore, the use of ultrasound irradiation increased the internalization by approximately 5%, irrespective of the presence of avidin on the E. coli cell surface. The percentages of GFP-expressing MCF-7 cells at 24h after bactofection were below 0.5% and 2% for the case with only avidin-modification of E. coli cell surface and only ultrasound irradiation, respectively. However, combining avidin modification with the ultrasound treatment increased this value to 8%. Thus, the use of avidin-modified bacteria in conjunction with ultrasound irradiation has potential as an effective strategy for tumor-targeted bactofection. PMID:24373691

  17. Comparison of Absorbents and Drugs for Internal Decorporation of Radiocesium: Advances of Polyvinyl Alcohol Hydrogel Microsphere Preparations Containing Magnetite and Prussian Blue.

    PubMed

    Tanaka, Izumi; Ishihara, Hiroshi; Yakumaru, Haruko; Tanaka, Mika; Yokochi, Kazuko; Tajima, Katsushi; Akashi, Makoto

    2016-01-01

    Radiocesium nuclides, used as a gamma ray source in various types of industrial equipments and found in nuclear waste, are strictly controlled to avoid their leakage into the environment. When large amounts of radiocesium are accidentally incorporated into the human body, decorporation therapy should be considered. Although standard decorporation methods have been studied since the 1960s and were established in the 1970s with the drug Radiogardase(®) (a Prussian blue preparation), application of recent advances in pharmacokinetics and ethical standards could improve these methods. Here we designed a modern dosage form of hydrogel containing cesium-absorbents to alleviate intestinal mucosa irritation due to the cesium-binding capacity of the absorbents. The effectiveness of the dosage form on fecal excretion was confirmed by quantitative mouse experiments. The total cesium excretion rate of the crystal form (1.37±0.09) was improved by the hydrogel form (1.52±0.10) at the same dose of Prussian blue, with a longer gastrointestinal tract transit time. Using a mouse model, we compared the effects of several drugs on fecal and urinary excretion of internal cesium, without the use of absorbents. Only phenylephrine hydrochloride significantly enhanced cesium excretion (excretion rate of 1.17±0.08) via the urinary pathway, whereas none of the diuretic drugs tested had this effect. These findings indicate that modifying the dosage form of cesium absorbents is important for the decorporation of internal radiocesium contamination. PMID:26725529

  18. Thermal damage of tissue during near-infrared laser irradiation with assistance of light-absorbing dye

    NASA Astrophysics Data System (ADS)

    Gnyawali, Surya C.; Le, Kelvin; Le, Henry; Wicksted, James P.; Bartels, Kenneth E.; Liu, Hong; Chen, Yichao; Chen, Wei R.

    2008-02-01

    The selective photothermal-tissue interaction using dye enhancement has been proven to be effective in minimizing the peripheral normal tissue damage during cancer treatment. It is important that the tissue-thermal damage be analyzed and the damage rate process be estimated before the photothermal-immunotherapy for cancer treatment. In this study, we have used the EMT6 mouse tumor model for the laser-tumor treatment with a simultaneous surface temperature measurement using infrared thermography. The images acquired were processed to obtain the temperature profiles. The saturation temperature and corresponding time of irradiation from the temporal profiles were used to calculate the damage parameter using Arrhenius rate process equation. The damage parameters obtained from six mice were compared. Our results of in vivo study show that the damage analyses agree with the previous in vitro study on skins.

  19. Effect of respiratory motion on internal radiation dosimetry

    SciTech Connect

    Xie, Tianwu; Zaidi, Habib

    2014-11-01

    Purpose: Estimation of the radiation dose to internal organs is essential for the assessment of radiation risks and benefits to patients undergoing diagnostic and therapeutic nuclear medicine procedures including PET. Respiratory motion induces notable internal organ displacement, which influences the absorbed dose for external exposure to radiation. However, to their knowledge, the effect of respiratory motion on internal radiation dosimetry has never been reported before. Methods: Thirteen computational models representing the adult male at different respiratory phases corresponding to the normal respiratory cycle were generated from the 4D dynamic XCAT phantom. Monte Carlo calculations were performed using the MCNP transport code to estimate the specific absorbed fractions (SAFs) of monoenergetic photons/electrons, the S-values of common positron-emitting radionuclides (C-11, N-13, O-15, F-18, Cu-64, Ga-68, Rb-82, Y-86, and I-124), and the absorbed dose of {sup 18}F-fluorodeoxyglucose ({sup 18}F-FDG) in 28 target regions for both the static (average of dynamic frames) and dynamic phantoms. Results: The self-absorbed dose for most organs/tissues is only slightly influenced by respiratory motion. However, for the lung, the self-absorbed SAF is about 11.5% higher at the peak exhale phase than the peak inhale phase for photon energies above 50 keV. The cross-absorbed dose is obviously affected by respiratory motion for many combinations of source-target pairs. The cross-absorbed S-values for the heart contents irradiating the lung are about 7.5% higher in the peak exhale phase than the peak inhale phase for different positron-emitting radionuclides. For {sup 18}F-FDG, organ absorbed doses are less influenced by respiratory motion. Conclusions: Respiration-induced volume variations of the lungs and the repositioning of internal organs affect the self-absorbed dose of the lungs and cross-absorbed dose between organs in internal radiation dosimetry. The dynamic

  20. Accelerated partial breast irradiation using once-daily fractionation: analysis of 312 cases with four years median follow-up

    PubMed Central

    2012-01-01

    Background There are limited data on accelerated partial breast irradiation (APBI) using external beam techniques. Moreover, there are recent reports of increased fibrosis and unacceptable cosmesis with APBI using external beam with BID fractionation. We adopted a once daily regimen of APBI with fractionation similar to that shown to be effective in a Canadian randomized trial of whole breast irradiation. It is unclear whether patients with DCIS or invasive lobular carcinoma (ILC) are suitable for APBI. Methods The retrospective cohort included 310 patients with 312 tumors of T1-T2N0-N1micM0 invasive ductal carcinoma (IDC), ILC, or Tis (DCIS) treated with APBI via external beam. Most patients were treated using IMRT with 16 daily fractions of 270 cGy to a dose of 4320 cGy. The target volume included the lumpectomy cavity plus 1.0 cm to account for microscopic disease and an additional 0.5 to 1.0 cm for setup uncertainty and breathing motion. Ipsilateral breast failure (IBF) was pathologically confirmed as a local failure (LF) or an elsewhere failure (EF). Results Median follow-up was 49 months. Among the 312 cases, 213 were IDC, 31 ILC, and 68 DCIS. Median tumor size was 1.0 cm. There were 9 IBFs (2.9%) including 5 LFs and 4 EFs. The IBF rates among patients with IDC, ILC, and DCIS were 2.4%, 3.2%, and 4.4%, respectively, with no significant difference between histologies. When patients were analyzed by the ASTRO APBI consensus statement risk groups, 32% of treated cases were considered suitable, 50% cautionary, and 18% unsuitable. The IBF rates among suitable, cautionary, and unsuitable patients were 4.0%, 2.6%, and 1.8%, respectively, with no significant difference between risk groups. Acute skin reactions were rare and long-term cosmetic outcome was very good to excellent. Conclusions External beam APBI with once daily fractionation has a low rate of IBF consistent with other published APBI studies. The ASTRO risk stratification did not differentiate a subset of

  1. Phase I trial of panobinostat and fractionated stereotactic re-irradiation therapy for recurrent high grade gliomas.

    PubMed

    Shi, Wenyin; Palmer, Joshua D; Werner-Wasik, Maria; Andrews, David W; Evans, James J; Glass, Jon; Kim, Lyndon; Bar-Ad, Voichita; Judy, Kevin; Farrell, Christopher; Simone, Nicole; Liu, Haisong; Dicker, Adam P; Lawrence, Yaacov R

    2016-05-01

    Panobinostat is an oral HDAC inhibitor with radiosensitizing activity. We investigated the safety, tolerability and preliminary efficacy of panobinostat combined with fractionated stereotactic re-irradiation therapy (FSRT) for recurrent high grade gliomas. Patients with recurrent high grade gliomas were enrolled in a 3 + 3 dose escalation study to determine dose limiting toxicities (DLTs), maximum tolerated dose (MTD), safety, tolerability, and preliminary efficacy. FSRT was prescribed to 30-35 Gy delivered in 10 fractions. Panobinostat was administrated concurrently with radiotherapy. Of 12 evaluable patients, 8 had recurrent GBM, and 4 had recurrent anaplastic astrocytoma. There were three grade 3 or higher toxicities in each the 10 and 30 mg cohorts. In the 30 mg cohort, there was one DLT; grade 4 neutropenia. One patient developed late grade 3 radionecrosis. The median follow up was 18.8 months. The PFS6 was 67, 33, and 83 % for 10, 20, and 30 mg cohorts, respectively. The median OS was 7.8, 6.1 and 16.1 months for the 10, 20 and 30 mg cohorts, respectively. Panobinostat administrated with FSRT is well tolerated at 30 mg. A phase II trial is warranted to assess the efficacy of panobinostat plus FSRT for recurrent glioma. PMID:26821711

  2. In vivo study of laser irradiation of fractionated drug administration based mechanism for effective photodynamic therapy in rat liver

    NASA Astrophysics Data System (ADS)

    Khurshid, A.; Firdous, S.; Ahmat, L.; Ferraria, J.; Vollet-Filho, J. D.; Kurachi, C.; Bagneto, V. S.; Nawaz, M.; Ikram, M.; Ahmad, M.

    2011-11-01

    Up-regulation of stress-activated proteins in cancer cells plays a protective role against photodynamic induced apoptosis. Post photodynamic therapy extracted normal rat liver tissue usually shows a fraction of surviving cells, the photodynamic resistant cells, residing in the necrotic region. To treat these photodynamic resistant cells a technique has been proposed based on fractionated drug administration of diluted photosensitizer, keeping the net concentration (5 mg/kg) constant, and subsequently varying drug light interval (DLI). Flourescence measurements were made for the presence of photosensitizer in a tissue. For qualitative analysis both histological and morphological studies were made. Although preliminary aim of this approach was not achieved but there were some interesting observation made i.e. for higher dilution of photosensitizer there was a sharp boundary between necrotic and normal portion of tissue. An increase in the absorption coefficient (α) from 2.7 → 2.9 was observed as photosensitizer was diluted while the corresponding threshold dose (D th) persistently decreases from (0.10 → 0.02) J/cm2 when irradiated with a 635 nm laser fluence of 150 J/cm2.

  3. Retroductal Submandibular Gland Instillation and Localized Fractionated Irradiation in a Rat Model of Salivary Hypofunction.

    PubMed

    Nair, Renjith Parameswaran; Zheng, Changyu; Sunavala-Dossabhoy, Gulshan

    2016-01-01

    Normal tissues that lie within the portals of radiation are inadvertently damaged. Salivary glands are often injured during head and neck radiotherapy. Irreparable cell damage results in a chronic loss of salivary function that impairs basic oral activities, and increases the risk of oral infections and dental caries. Salivary hypofunction and its complications gravely impact a patient's comfort. Current symptomatic management of the condition is ineffective, and newer therapies to assuage the condition are needed. Salivary glands are exocrine glands, which expel their secretions into the mouth via excretory ducts. Cannulation of these ducts provides direct access to the glands. Retroductal delivery of a contrast agent to major salivary glands is a routine out-patient procedure for diagnostic imaging. Using a similar procedure, localized treatment of the glands is feasible. However, performing this technique in preclinical studies with small animals poses unique challenges. In this study we describe the technique of retroductal administration in rat submandibular glands, a procedure that was refined in Dr. Bruce Baum's laboratory (NIH)(1), and lay out a procedure for local gland irradiation. PMID:27168158

  4. An experimental investigation of fractionation by sputter deposition. [application to solar wind irradiation of lunar soil

    NASA Technical Reports Server (NTRS)

    Paruso, D. M.; Cassidy, W. A.; Hapke, B. W.

    1978-01-01

    Artificial glass targets composed of elements varying widely in atomic weight were irradiated at an angle of incidence of 45 deg by 2-keV hydrogen ions at a current density of .33 mA/sq cm, and sputtered atoms were caught on a molybdenum film. Analyses of the sputter-deposited films and unsputtered target glasses were carried out by electron microprobe. The backward-sputtered component was found to be enriched in elements of low atomic weight, while the forward-sputtered component was enriched in heavy atoms. These results indicate that at the lunar surface lighter elements and isotopes would tend to be ejected in backward directions, escaping directly through the openings which admit bombarding ions without first striking an adjacent grain surface; heavy elements and isotopes would be forward-sputtered deeper into the soil and be preferentially retained, contributing to the reported enrichments of heavy elements and isotopes. Additional results show that the binding energy of an element in its oxide form influences the sticking coefficient of a sputtered atom; elements of low binding energy are likely to desorb, while elements of high binding energy tend to stick to the first bounce surface.

  5. Acute and Short-Term Toxicities of Conventionally Fractionated Versus Hypofractionated Whole Breast Irradiation in a Prospective, Randomized Trial

    PubMed Central

    Shaitelman, Simona F.; Schlembach, Pamela J.; Arzu, Isidora; Ballo, Matthew; Bloom, Elizabeth S.; Buchholz, Daniel; Chronowski, Gregory M.; Dvorak, Tomas; Grade, Emily; Hoffman, Karen E.; Kelly, Patrick; Ludwig, Michelle; Perkins, George H.; Reed, Valerie; Shah, Shalin; Stauder, Michael C.; Strom, Eric A.; Tereffe, Welela; Woodward, Wendy A.; Ensor, Joe; Baumann, Donald; Thompson, Alastair M.; Amaya, Diana; Davis, Tanisha; Guerra, William; Hamblin, Lois; Hortobagyi, Gabriel; Hunt, Kelly K.; Buchholz, Thomas A.; Smith, Benjamin D.

    2015-01-01

    IMPORTANCE The most appropriate dose-fractionation for whole breast irradiation (WBI) remains uncertain. OBJECTIVE To assess acute and six-month toxicity and quality of life (QoL) with conventionally fractionated WBI (CF-WBI) versus hypofractionated WBI (HF-WBI). DESIGN Unblinded randomized trial of CF-WBI (n=149; 50 Gy/25 fractions + boost [10–14 Gy/5–7 fractions]) versus HF-WBI (n=138; 42.56 Gy/16 fractions + boost [10–12.5 Gy/4–5 fractions]). SETTING Community-based and academic cancer centers. PARTICIPANTS 287 women age ≥ 40 years with stage 0–II breast cancer treated with breast-conserving surgery for whom whole breast irradiation without addition of a third field was recommended. 76% (n=217) were overweight or obese. Patients were enrolled from February 2011 through February 2014. INTERVENTION(S) FOR CLINICAL TRIALS CF-WBI versus HF-WBI. MAIN OUTCOME MEASURES Physician-reported acute and six-month toxicities using NCICTCv4.0 and patient-reported QoL using the FACT-B version 4. All analyses were intention-to-treat, with outcomes compared using chi-square, Cochran-Armitage test, and ordinal logistic regression. Patients were followed for a minimum of 6 months. RESULTS Treatment arms were well-matched for baseline characteristics including FACT-B total score (P=0.46) and individual QoL items such as lack of energy (P=0.86) and trouble meeting family needs (P=0.54). Maximal physician-reported acute dermatitis (P<0.001), pruritus (P<0.001), breast pain (P=0.001), hyperpigmentation (P=0.002), and fatigue (P=0.02) during radiation were lower in patients randomized to HF-WBI. Overall grade ≥2 acute toxicity was less with HF-WBI vs. CF-WBI (47% vs. 78%; P<0.001). Six months after radiation, physicians reported less fatigue in patients randomized to HF-WBI (P=0.01), and patients randomized to HF-WBI reported less lack of energy (P<0.001) and less trouble meeting family needs (P=0.01). Multivariable regression confirmed the superiority of HF-WBI in terms

  6. Internal stress distribution for generating closure domains in laser-irradiated Fe–3%Si(110) steels

    SciTech Connect

    Iwata, Keiji; Imafuku, Muneyuki; Orihara, Hideto; Sakai, Yusuke; Ohya, Shin-Ichi; Suzuki, Tamaki; Shobu, Takahisa; Akita, Koichi; Ishiyama, Kazushi

    2015-05-07

    Internal stress distribution for generating closure domains occurring in laser-irradiated Fe–3%Si(110) steels was investigated using high-energy X-ray analysis and domain theory based on the variational principle. The measured triaxial stresses inside the specimen were compressive and the stress in the rolling direction became more dominant than stresses in the other directions. The calculations based on the variational principle of magnetic energy for closure domains showed that the measured triaxial stresses made the closure domains more stable than the basic domain without closure domains. The experimental and calculation results reveal that the laser-introduced internal stresses result in the occurrence of the closure domains.

  7. Persistent DNA Damage in Spermatogonial Stem Cells After Fractionated Low-Dose Irradiation of Testicular Tissue

    SciTech Connect

    Grewenig, Angelika; Schuler, Nadine; Rübe, Claudia E.

    2015-08-01

    Purpose: Testicular spermatogenesis is extremely sensitive to radiation-induced damage, and even low scattered doses to testis from radiation therapy may pose reproductive risks with potential treatment-related infertility. Radiation-induced DNA double-strand breaks (DSBs) represent the greatest threat to the genomic integrity of spermatogonial stem cells (SSCs), which are essential to maintain spermatogenesis and prevent reproduction failure. Methods and Materials: During daily low-dose radiation with 100 mGy or 10 mGy, radiation-induced DSBs were monitored in mouse testis by quantifying 53 binding protein 1 (53BP-1) foci in SSCs within their stem cell niche. The accumulation of DSBs was correlated with proliferation, differentiation, and apoptosis of testicular germ cell populations. Results: Even very low doses of ionizing radiation arrested spermatogenesis, primarily by inducing apoptosis in spermatogonia. Eventual recovery of spermatogenesis depended on the survival of SSCs and their functional ability to proliferate and differentiate to provide adequate numbers of differentiating spermatogonia. Importantly, apoptosis-resistant SSCs resulted in increased 53BP-1 foci levels during, and even several months after, fractionated low-dose radiation, suggesting that surviving SSCs have accumulated an increased load of DNA damage. Conclusions: SSCs revealed elevated levels of DSBs for weeks after radiation, and if these DSBs persist through differentiation to spermatozoa, this may have severe consequences for the genomic integrity of the fertilizing sperm.

  8. Comparison of the Absorbed Dose for 99mTc-Diethylenetriaminepentaacetic Acid and 99mTc-Ethylenedicysteine Radiopharmaceuticals using Medical Internal Radiation Dosimetry

    PubMed Central

    Pirdamooie, Shokufeh; Shanei, Ahmad; Moslehi, Masoud

    2015-01-01

    The aim of this study was the investigation of absorbed dose to the kidneys, spleen, and liver during technetium-99 m ethylene dicysteine and technetium-99 m diethylenetriaminepentaacetic acid (99mTc-EC and 99mTc-DTPA) kidney scan. Patients who had been prepared for the kidney scan, were divided into two groups (Groups 1 and 2). The first group (Group 1) and the second group (Group 2) received intravenous injection of 99mTc-EC and 99mTc-DTP, respectively. A certain amount of radiopharmaceuticals was injected into each patient and was immediately imaged with dual-head gamma camera to calculate the activity through the conjugated view method. Then, the doses of kidney, liver, and spleen were measured using medical internal radiation dosimetry method. Finally, absorbed dose of these organs was compared. Based on these different results (P < 0.05), organs absorbed dose was significantly less with radiopharmaceutical 99mTc-EC as compared with 99mTc-DTPA. PMID:26284173

  9. Pretransplant pulmonary function tests predict risk of mortality following fractionated total body irradiation and allogeneic peripheral blood stem cell transplant

    SciTech Connect

    Singh, Anurag K. . E-mail: singan@mail.nih.gov; Karimpour, Shervin E.; Savani, Bipin N.; Guion, Peter M.S.; Hope, Andrew J.; Mansueti, John R.; Ning, Holly; Altemus, Rosemary M. Ph.D.; Wu, Colin O.; Barrett, A. John

    2006-10-01

    Purpose: To determine the value of pulmonary function tests (PFTs) done before peripheral blood stem cell transplant (PBSCT) in predicting mortality after total body irradiation (TBI) performed with or without dose reduction to the lung. Methods and Materials: From 1997 to 2004, 146 consecutive patients with hematologic malignancies received fractionated TBI before PBSCT. With regimen A (n = 85), patients were treated without lung dose reduction to 13.6 gray (Gy). In regimen B (n = 35), total body dose was decreased to 12 Gy (1.5 Gy twice per day for 4 days) and lung dose was limited to 9 Gy by use of lung shielding. In regimen C (n = 26), lung dose was reduced to 6 Gy. All patients received PFTs before treatment, 90 days after treatment, and annually. Results: Median follow-up was 44 months (range, 12-90 months). Sixty-one patients had combined ventilation/diffusion capacity deficits defined as both a forced expiratory volume in the first second (FEV{sub 1}) and a diffusion capacity of carbon dioxide (DLCO) <100% predicted. In this group, there was a 20% improvement in one-year overall survival with lung dose reduction (70 vs. 50%, log-rank test p = 0.042). Conclusion: Among those with combined ventilation/diffusion capacity deficits, lung dose reduction during TBI significantly improved survival.

  10. IFMIF - International Fusion Materials Irradiation Facility Conceptual Design Activity/Interim Report

    SciTech Connect

    Rennich, M.J.

    1995-12-01

    Environmental acceptability, safety, and economic viability win ultimately be the keys to the widespread introduction of fusion power. This will entail the development of radiation- resistant and low- activation materials. These low-activation materials must also survive exposure to damage from neutrons having an energy spectrum peaked near 14 MeV with annual radiation doses in the range of 20 displacements per atom (dpa). Testing of candidate materials, therefore, requires a high-flux source of high energy neutrons. The problem is that there is currently no high-flux source of neutrons in the energy range above a few MeV. The goal, is therefore, to provide an irradiation facility for use by fusion material scientists in the search for low-activation and damage-resistant materials. An accellerator-based neutron source has been established through a number of international studies and workshops` as an essential step for materials development and testing. The mission of the International Fusion Materials Irradiation Facility (IFMIF) is to provide an accelerator-based, deuterium-lithium (D-Li) neutron source to produce high energy neutrons at sufficient intensity and irradiation volume to test samples of candidate materials up to about a full lifetime of anticipated use in fusion energy reactors. would also provide calibration and validation of data from fission reactor and other accelerator-based irradiation tests. It would generate material- specific activation and radiological properties data, and support the analysis of materials for use in safety, maintenance, recycling, decommissioning, and waste disposal systems.

  11. A review of irradiation effects on LWR core internal materials - IASCC susceptibility and crack growth rates of austenitic stainless steels

    NASA Astrophysics Data System (ADS)

    Chopra, O. K.; Rao, A. S.

    2011-02-01

    Austenitic stainless steels (SSs) are used extensively as structural alloys in the internal components of light water reactor (LWR) pressure vessels because of their relatively high strength, ductility, and fracture toughness. However, exposure to neutron irradiation for extended periods changes the microstructure (radiation hardening) and microchemistry (radiation-induced segregation) of these steels, and degrades their fracture properties. Irradiation-assisted stress corrosion cracking (IASCC) is another degradation process that affects LWR internal components exposed to neutron radiation. The existing data on irradiated austenitic SSs were reviewed to evaluate the effects of key parameters such as material composition, irradiation dose, and water chemistry on IASCC susceptibility and crack growth rates of these materials in LWR environments. The significance of microstructural and microchemistry changes in the material on IASCC susceptibility is also discussed. The results are used to determine (a) the threshold fluence for IASCC and (b) the disposition curves for cyclic and IASCC growth rates for irradiated SSs in LWR environments.

  12. The Solar Spectral Irradiance Measured on Board the International Space Station and the Picard Spacecraft

    NASA Astrophysics Data System (ADS)

    Thuillier, G. O.; Bolsee, D.; Schmidtke, G.; Schmutz, W. K.

    2011-12-01

    On board the International Space Station, the spectrometers SOL-ACES and SOLSPEC measure the solar spectrum irradiance from 17 to 150 nm and 170 to 2900 nm, respectively. On board PICARD launched on 15 June 2010, the PREMOS instrument consists in a radiometer and several sunphotometers operated at several fixed wavelengths. We shall present spectra at different solar activity levels as well as their quoted accuracy. Comparison with similar data from other missions presently running in space will be shown incorporating the PREMOS measurements. Some special solar events will be also presented and interpreted.

  13. Effect of weight fraction of carbon black and number of plies of E-glass fiber to reflection loss of E-glass/ripoxy composite for radar absorbing structure (RAS)

    NASA Astrophysics Data System (ADS)

    Widyastuti, Ramadhan, Rizal; Ardhyananta, Hosta; Zainuri, Mochamad

    2013-09-01

    Nowadays, studies on investigating radar absorbing structure (RAS) using fiber reinforced polymeric (FRP) composite materials are becoming popular research field because the electromagnetic properties of FRP composites can be tailored effectively by just adding some electromagnetic powders, such as carbon black, ferrite, carbonyl iron, and etc., to the matrix of composites. The RAS works not only as a load bearing structure to hold the antenna system, but also has the important function of absorbing the in-band electromagnetic wave coming from the electromagnetic energy of tracking systems. In this study, E-glass fiber reinforced ripoxy resin composite was fabricated by blending the conductive carbon black (Ketjenblack EC300J) with the binder matrix of the composite material and maximizing the coefficient of absorption more than 90% (more than -10 dB) within the X-band frequency (8 - 12 GHz). It was measured by electrical conductivity (LCR meter) and vector network analyzer (VNA). Finally, the composite RAS with 0.02 weight fraction of carbon black and 4 plies of E-glass fiber showed thickness of 2.1 mm, electrical conductivity of 8.33 × 10-6 S/m, and maximum reflection loss of -27.123 dB, which can absorb more than 90% of incident EM wave throughout the entire X-band frequency range, has been developed.

  14. A case report of image-based dosimetry of bone metastases with Alpharadin ((223)Ra-dichloride) therapy: inter-fraction variability of absorbed dose and follow-up.

    PubMed

    Pacilio, Massimiliano; Ventroni, Guido; Cassano, Bartolomeo; Ialongo, Pasquale; Lorenzon, Leda; Di Castro, Elisabetta; Recine, Federica; Sternberg, Cora N; Mango, Lucio

    2016-02-01

    A 70-year-old man affected by bone metastases from castration resistant prostate cancer underwent Alpharadin ((223)Ra-dichloride) therapy (6 administrations of 50 kBq per kg i.v., once every 4 weeks). The inter-fraction variability of the absorbed dose to lesions was evaluated for four injections. Dosimetric assessments were performed following the MIRD approach and a recently published methodology. The mean absorbed dose and standard deviation for 4 lesions [mean (σ %)] were: 434 mGy (15%) and 516 mGy (21%) for the right and left humeral head, 1205 mGy (14%) and 781 mGy (8%) for the right and left glenoid. The estimated total absorbed dose after the whole treatment, considering also the relative-biological effectiveness of alpha particles (RBE = 5), yielded a D RBE range of 13-36 Gy. A good correlation between (99m)Tc and (223)Ra uptake was obtained (R (2) = 0.7613). The tumour-non-tumour (TNT) ratio of 8 lesions (those above, plus 4 additional), monitored by six (99m)Tc-MDP bone scans over a period of about 10 months, evidenced a TNT reduction in two lesions (-42 and -48 %), but in most lesions the TNT remained fairly constant, evidencing that (223)Ra-dichloride therapy tends to prevent further progression of osseous disease, leading to chronicity of the metastatic status. PMID:26613714

  15. IAEA international studies on irradiation embrittlement of reactor pressure vessel steels

    SciTech Connect

    Brumovsky, M.; Steele, L.E.

    1997-02-01

    In last 25 years, three phases a Co-operative Research Programme on Irradiation Embrittlement of Reactor Pressure Vessel Steels has been organized by the International Atomic Energy Agency. This programme started with eight countries in 1971 and finally 16 countries took part in phase III of the Programme in 1983. Several main efforts were put into preparation of the programme, but the principal task was concentrated on an international comparison of radiation damage characterization by different laboratories for steels of {open_quotes}old{close_quotes} (with high impurity contents) and {open_quotes}advanced{close_quotes} (with low impurity contents) types as well as on development of small scale fracture mechanics procedures applicable to reactor pressure vessel surveillance programmes. This year, a new programme has been opened, concentrated mostly on small scale fracture mechanics testing.

  16. On the definition of absorbed dose

    NASA Astrophysics Data System (ADS)

    Grusell, Erik

    2015-02-01

    Purpose: The quantity absorbed dose is used extensively in all areas concerning the interaction of ionizing radiation with biological organisms, as well as with matter in general. The most recent and authoritative definition of absorbed dose is given by the International Commission on Radiation Units and Measurements (ICRU) in ICRU Report 85. However, that definition is incomplete. The purpose of the present work is to give a rigorous definition of absorbed dose. Methods: Absorbed dose is defined in terms of the random variable specific energy imparted. A random variable is a mathematical function, and it cannot be defined without specifying its domain of definition which is a probability space. This is not done in report 85 by the ICRU, mentioned above. Results: In the present work a definition of a suitable probability space is given, so that a rigorous definition of absorbed dose is possible. This necessarily includes the specification of the experiment which the probability space describes. In this case this is an irradiation, which is specified by the initial particles released and by the material objects which can interact with the radiation. Some consequences are discussed. Specific energy imparted is defined for a volume, and the definition of absorbed dose as a point function involves the specific energy imparted for a small mass contained in a volume surrounding the point. A possible more precise definition of this volume is suggested and discussed. Conclusions: The importance of absorbed dose motivates a proper definition, and one is given in the present work. No rigorous definition has been presented before.

  17. Renal tubulointerstitial changes after internal irradiation with alpha-particle-emitting actinium daughters.

    PubMed

    Jaggi, Jaspreet Singh; Seshan, Surya V; McDevitt, Michael R; LaPerle, Krista; Sgouros, George; Scheinberg, David A

    2005-09-01

    The effect of external gamma irradiation on the kidneys is well described. However, the mechanisms of radiation nephropathy as a consequence of targeted radionuclide therapies are poorly understood. The functional and morphologic changes were studied chronologically (from 10 to 40 wk) in mouse kidneys after injection with an actinium-225 (225Ac) nanogenerator, a molecular-sized, antibody-targeted, in vivo generator of alpha-particle-emitting elements. Renal irradiation from free, radioactive daughters of 225Ac led to time-dependent reduction in renal function manifesting as increase in blood urea nitrogen. The histopathologic changes corresponded with the decline in renal function. Glomerular, tubular, and endothelial cell nuclear pleomorphism and focal tubular cell injury, lysis, and karyorrhexis were observed as early as 10 wk. Progressive thinning of the cortex as a result of widespread tubulolysis, collapsed tubules, glomerular crowding, decrease in glomerular cellularity, interstitial inflammation, and an elevated juxtaglomerular cell count were noted at 20 to 30 wk after treatment. By 35 to 40 wk, regeneration of simplified tubules with tubular atrophy and loss with focal, mild interstitial fibrosis had occurred. A lower juxtaglomerular cell count with focal cytoplasmic vacuolization, suggesting increased degranulation, was also observed in this period. A focal increase in tubular and interstitial cell TGF-beta1 expression starting at 20 wk, peaking at 25 wk, and later declining in intensity with mild increase in the extracellular matrix deposition was noticed. These findings suggest that internally delivered alpha-particle irradiation-induced loss of tubular epithelial cells triggers a chain of adaptive changes that result in progressive renal parenchymal damage accompanied by a loss of renal function. These findings are dissimilar to those seen after gamma or beta irradiation of kidneys. PMID:15987754

  18. High-dose total-body irradiation and autologous marrow reconstitution in dogs: dose-rate-related acute toxicity and fractionation-dependent long-term survival

    SciTech Connect

    Deeg, H.J.; Storb, R.; Weiden, P.L.; Schumacher, D.; Shulman, H.; Graham, T.; Thomas, E.D.

    1981-11-01

    Beagle dogs treated by total-body irradiation (TBI) were given autologous marrow grafts in order to avoid death from marrow toxicity. Acute and delayed non-marrow toxicities of high single-dose (27 dogs) and fractionated TBI (20 dogs) delivered at 0.05 or 0.1 Gy/min were compared. Fractionated TBI was given in increments of 2 Gy every 6 hr for three increments per day. Acute toxicity and early mortality (<1 month) at identical total irradiation doses were comparable for dogs given fractionated or single-dose TBI. With single-dose TBI, 14, 16, and 18 Gy, respectively, given at 0.05 Gy/min, 0/5, 5/5, and 2/2 dogs died from acute toxicity; with 10, 12, and 14 Gy, respectively, given at 0.1 Gy/min, 1/5, 4/5, and 5/5 dogs died acutely. With fractionated TBI, 14 and 16 Gy, respectively, given at 0.1 Gy/min, 1/5, 4/5, and 2/2 dogs died auctely. Early deaths were due to radiation enteritis with or without associated septicemia (29 dogs; less than or equal to Day 10). Three dogs given 10 Gy of TBI at 0.1 Gy/min died from bacterial pneumonia; one (Day 18) had been given fractionated and two (Days 14, 22) single-dose TBI. Fifteen dogs survived beyond 1 month; eight of these had single-dose TBI (10-14 Gy) and all died within 7 months of irradiation from a syndrome consisting of hepatic damage, pancreatic fibrosis, malnutrition, wasting, and anemia. Seven of the 15 had fractionated TBI, and only one (14 Gy) died on Day 33 from hepatic failure, whereas 6 (10-14 Gy) are alive and well 250 to 500 days after irradiation. In conclusion, fractionated TBI did not offer advantages over single-dose TBI with regard to acute toxicity and early mortality; rather, these were dependent upon the total dose of TBI. The total acutely tolerated dose was dependent upon the exposure rate; however, only dogs given fractionated TBI became healthy long-term survivors.

  19. Final report (Grant No. DOE DE-FG02-97ER62366) [Retrieval of cloud fraction and type using broadband diffuse and total shortwave irradiance measurements

    SciTech Connect

    Clothiaux, Eugene

    2001-05-17

    The primary research effort supported by Grant No. DOE DEFG02-97ER62366 titled ''Retrieval of Cloud Fraction and Type Using Broadband Diffuse and Total Shortwave Irradiance Measurements'' was application of clear-sky identification and cloud fraction estimation algorithms developed by Charles N. Long and Thomas P. Ackerman to the downwelling total, direct and diffuse shortwave irradiance measurements made at all of the central, boundary, and extended facilities of the DOE Atmospheric Radiation Measurement (ARM) Program Southern Great Plains (SOP) site. Goals of the research were finalization and publication of the two algorithms in the peer-reviewed literature and operational application of them to all of aforementioned data streams from the ARM SGP site. The clear-sky identification algorithm was published as Long and Ackerman (2000) in the Journal of Geophysical Research, while a description of the cloud fraction estimation algorithm made it to the scientific literature as Long et al. (1999) in the Proceedings of the 10th American Meteorological Association Conference on Atmospheric Radiation held in Madison, Wisconsin. The cloud fraction estimation algorithm relies on empirical relationships between the outputs of the clear-sky identification algorithm and cloud fraction; as such, the cloud fraction estimation algorithm requires significant amounts of data both to properly develop the empirical relationships and to thoroughly test them. With this perspective in mind the major focus of our research efforts in the later half of the project became the operational implementation of the clear-sky identification algorithm on DOE ARM SGP data so that we could develop the data set necessary for final tuning of the cloud fraction estimation algorithm in research extending beyond the lifetime of the project.

  20. The AT{sub 1} Receptor Antagonist, L-158,809, Prevents or Ameliorates Fractionated Whole-Brain Irradiation-Induced Cognitive Impairment

    SciTech Connect

    Robbins, Mike E. Payne, Valerie B.S.; Tommasi, Ellen B.S.; Diz, Debra I.; Hsu, Fang-Chi; Brown, William R.; Wheeler, Kenneth T.; Olson, John; Zhao Weiling

    2009-02-01

    Purpose: We hypothesized that administration of the angiotensin type 1 (AT1) receptor antagonist, L-158,809, to young adult male rats would prevent or ameliorate fractionated whole-brain irradiation (WBI)-induced cognitive impairment. Materials and Methods: Groups of 80 young adult male Fischer 344 x Brown Norway (F344xBN) rats, 12-14 weeks old, received either: (1) fractionated WBI; 40 Gy of {gamma} rays in 4 weeks, 2 fractions/week, (2) sham-irradiation; (3) WBI plus L-158,809 (20 mg/L drinking water) starting 3 days prior, during, and for 14, 28, or 54 weeks postirradiation; and (4) sham-irradiation plus L-158,809 for 14, 28, or 54 weeks postirradiation. An additional group of rats (n = 20) received L-158,809 before, during, and for 5 weeks postirradiation, after which they received normal drinking water up to 28 weeks postirradiation. Results: Administration of L-158,809 before, during, and for 28 or 54 weeks after fractionated WBI prevented or ameliorated the radiation-induced cognitive impairment observed 26 and 52 weeks postirradiation. Moreover, giving L-158,809 before, during, and for only 5 weeks postirradiation ameliorated the significant cognitive impairment observed 26 weeks postirradiation. These radiation-induced cognitive impairments occurred without any changes in brain metabolites or gross histologic changes assessed at 28 and 54 weeks postirradiation, respectively. Conclusions: Administering L-158,809 before, during, and after fractionated WBI can prevent or ameliorate the chronic, progressive, cognitive impairment observed in rats at 26 and 52 weeks postirradiation. These findings offer the promise of improving the quality of life for brain tumor patients.

  1. Irradiance formations of on-axis Lambertian pointlike sources in polygonal total-internal-reflection straight light pipes.

    PubMed

    Cheng, Yi-Kai; Wang, Meng-Hua; Chern, Jyh-Long

    2007-09-01

    Different geometric shapes of light pipes cause different irradiance distributions. We analytically explore the irradiance distributions of on-axis Lambertian pointlike sources in polygonal total-internal-reflection (TIR) straight light pipes. It is analytically shown that the irradiance of pentagonal light pipes concentrates on the center of the exit plane. Numerical verifications are also provided, and experimental explorations with different shapes of acrylic light pipes are carried out for comparison. We also analyze the influence of light-pipe length on distribution uniformity and deduce the smallest uniform-mixing length/circumradius ratios for polygonal light pipes. PMID:17767244

  2. High Dose-Per-Fraction Irradiation of Limited Lung Volumes Using an Image-Guided, Highly Focused Irradiator: Simulating Stereotactic Body Radiotherapy Regimens in a Small-Animal Model

    SciTech Connect

    Cho, Jaeho; Kodym, Reinhard; Seliounine, Serguei

    2010-07-01

    Purpose: To investigate the underlying biology associated with stereotactic body radiotherapy (SBRT), both in vivo models and image-guided, highly focal irradiation systems are necessary. Here, we describe such an irradiation system and use it to examine normal tissue toxicity in a small-animal model at lung volumes similar to those associated with human therapy. Methods and Materials: High-dose radiation was delivered to a small volume of the left lung of C3H/HeJCr mice using a small-animal stereotactic irradiator. The irradiator has a collimation mechanism to produce focal radiation beams, an imaging subsystem consisting of a fluorescent screen coupled to a charge-coupled device camera, and a manual positioning stage. Histopathologic examination and micro-CT were used to evaluate the radiation response. Results: Focal obliteration of the alveoli by fibrous connective tissue, hyperplasia of the bronchiolar epithelium, and presence of a small number of inflammatory cells are the main reactions to low-volume/high-dose irradiation of the mouse lung. The tissue response suggested a radiation dose threshold for early phase fibrosis lying between 40 and 100 Gy. The irradiation system satisfied our requirements of high-dose-rate, small beam diameter, and precise localization and verification. Conclusions: We have established an experimental model and image-guided animal irradiation system for the study of high dose per fraction irradiations such as those used with SBRT at volumes analogous to those used in human beings. It will also allow the targeting of specific anatomical structures of the thorax or ultimately, orthotopic tumors of the lung.

  3. Installation and first operation of the International Fusion Materials Irradiation Facility injector at the Rokkasho site.

    PubMed

    Gobin, Raphael; Bogard, Daniel; Bolzon, Benoit; Bourdelle, Gilles; Chauvin, Nicolas; Chel, Stéphane; Girardot, Patrick; Gomes, Adelino; Guiho, Patrice; Harrault, Francis; Loiseau, Denis; Lussignol, Yves; Misiara, Nicolas; Roger, Arnaud; Senée, Franck; Valette, Matthieu; Cara, Philippe; Duglué, Daniel; Gex, Dominique; Okumura, Yoshikazu; Ayala, Juan Marcos; Knaster, Juan; Marqueta, Alvaro; Kasugai, Atsushi; O'Hira, Shigeru; Shinto, Katsuhiro; Takahashi, Hiroki

    2016-02-01

    The International Fusion Materials Irradiation Facility (IFMIF) linear IFMIF prototype accelerator injector dedicated to high intensity deuteron beam production has been designed, built, and tested at CEA/Saclay between 2008 and 2012. After the completion of the acceptance tests at Saclay, the injector has been fully sent to Japan. The re-assembly of the injector has been performed between March and May 2014. Then after the check-out phase, the production of the first proton beam occurred in November 2014. Hydrogen and deuteron beam commissioning is now in progress after having proceeded with the final tests on the entire injector equipment including high power diagnostics. This article reports the different phases of the injector installation pointing out the safety and security needs, as well as the first beam production results in Japan and chopper tests. Detailed operation and commissioning results (with H(+) and D(+) 100 keV beams) are reported in a second article. PMID:26931944

  4. Present status of the liquid lithium target facility in the international fusion materials irradiation facility (IFMIF)

    NASA Astrophysics Data System (ADS)

    Nakamura, Hiroo; Riccardi, B.; Loginov, N.; Ara, K.; Burgazzi, L.; Cevolani, S.; Dell'Orco, G.; Fazio, C.; Giusti, D.; Horiike, H.; Ida, M.; Ise, H.; Kakui, H.; Matsui, H.; Micciche, G.; Muroga, T.; Nakamura, Hideo; Shimizu, K.; Sugimoto, M.; Suzuki, A.; Takeuchi, H.; Tanaka, S.; Yoneoka, T.

    2004-08-01

    During the three year key element technology phase of the International Fusion Materials Irradiation Facility (IFMIF) project, completed at the end of 2002, key technologies have been validated. In this paper, these results are summarized. A water jet experiment simulating Li flow validated stable flow up to 20 m/s with a double reducer nozzle. In addition, a small Li loop experiment validated stable Li flow up to 14 m/s. To control the nitrogen content in Li below 10 wppm will require surface area of a V-Ti alloy getter of 135 m 2. Conceptual designs of diagnostics have been carried out. Moreover, the concept of a remote handling system to replace the back wall based on `cut and reweld' and `bayonet' options has been established. Analysis by FMEA showed safe operation of the target system. Recent activities in the transition phase, started in 2003, and plan for the next phase are also described.

  5. Installation and first operation of the International Fusion Materials Irradiation Facility injector at the Rokkasho site

    NASA Astrophysics Data System (ADS)

    Gobin, Raphael; Bogard, Daniel; Bolzon, Benoit; Bourdelle, Gilles; Chauvin, Nicolas; Chel, Stéphane; Girardot, Patrick; Gomes, Adelino; Guiho, Patrice; Harrault, Francis; Loiseau, Denis; Lussignol, Yves; Misiara, Nicolas; Roger, Arnaud; Senée, Franck; Valette, Matthieu; Cara, Philippe; Duglué, Daniel; Gex, Dominique; Okumura, Yoshikazu; Marcos Ayala, Juan; Knaster, Juan; Marqueta, Alvaro; Kasugai, Atsushi; O'Hira, Shigeru; Shinto, Katsuhiro; Takahashi, Hiroki

    2016-02-01

    The International Fusion Materials Irradiation Facility (IFMIF) linear IFMIF prototype accelerator injector dedicated to high intensity deuteron beam production has been designed, built, and tested at CEA/Saclay between 2008 and 2012. After the completion of the acceptance tests at Saclay, the injector has been fully sent to Japan. The re-assembly of the injector has been performed between March and May 2014. Then after the check-out phase, the production of the first proton beam occurred in November 2014. Hydrogen and deuteron beam commissioning is now in progress after having proceeded with the final tests on the entire injector equipment including high power diagnostics. This article reports the different phases of the injector installation pointing out the safety and security needs, as well as the first beam production results in Japan and chopper tests. Detailed operation and commissioning results (with H+ and D+ 100 keV beams) are reported in a second article.

  6. Sound Absorbers

    NASA Astrophysics Data System (ADS)

    Fuchs, H. V.; Möser, M.

    Sound absorption indicates the transformation of sound energy into heat. It is, for instance, employed to design the acoustics in rooms. The noise emitted by machinery and plants shall be reduced before arriving at a workplace; auditoria such as lecture rooms or concert halls require a certain reverberation time. Such design goals are realised by installing absorbing components at the walls with well-defined absorption characteristics, which are adjusted for corresponding demands. Sound absorbers also play an important role in acoustic capsules, ducts and screens to avoid sound immission from noise intensive environments into the neighbourhood.

  7. Can a Satellite-Derived Estimate of the Fraction of PAR Absorbed by Chlorophyll (FAPAR(sub chl)) Improve Predictions of Light-Use Efficiency and Ecosystem Photosynthesis for a Boreal Aspen Forest?

    NASA Technical Reports Server (NTRS)

    Zhang, Qingyuan; Middleton, Elizabeth M.; Margolis, Hank A.; Drolet, Guillaume G.; Barr, Alan A.; Black, T. Andrew

    2009-01-01

    Gross primary production (GPP) is a key terrestrial ecophysiological process that links atmospheric composition and vegetation processes. Study of GPP is important to global carbon cycles and global warming. One of the most important of these processes, plant photosynthesis, requires solar radiation in the 0.4-0.7 micron range (also known as photosynthetically active radiation or PAR), water, carbon dioxide (CO2), and nutrients. A vegetation canopy is composed primarily of photosynthetically active vegetation (PAV) and non-photosynthetic vegetation (NPV; e.g., senescent foliage, branches and stems). A green leaf is composed of chlorophyll and various proportions of nonphotosynthetic components (e.g., other pigments in the leaf, primary/secondary/tertiary veins, and cell walls). The fraction of PAR absorbed by whole vegetation canopy (FAPAR(sub canopy)) has been widely used in satellite-based Production Efficiency Models to estimate GPP (as a product of FAPAR(sub canopy)x PAR x LUE(sub canopy), where LUE(sub canopy) is light use efficiency at canopy level). However, only the PAR absorbed by chlorophyll (a product of FAPAR(sub chl) x PAR) is used for photosynthesis. Therefore, remote sensing driven biogeochemical models that use FAPAR(sub chl) in estimating GPP (as a product of FAPAR(sub chl x PAR x LUE(sub chl) are more likely to be consistent with plant photosynthesis processes.

  8. Single-Dose and Fractionated Irradiation Promote Initiation and Progression of Atherosclerosis and Induce an Inflammatory Plaque Phenotype in ApoE{sup -/-} Mice

    SciTech Connect

    Hoving, Saske; Heeneman, Sylvia; Gijbels, Marion J.J.; Poele, Johannes A.M. te; Russell, Nicola S.; Daemen, Mat J.A.P.; Stewart, Fiona A.

    2008-07-01

    Purpose: Increased risk of atherosclerosis and stroke has been demonstrated in patients receiving radiotherapy for Hodgkin's lymphoma and head-and-neck cancer. We previously showed that 14 Gy to the carotid arteries of hypercholesterolemic ApoE{sup -/-} mice resulted in accelerated development of macrophage-rich, inflammatory atherosclerotic lesions. Here we investigate whether clinically relevant fractionated irradiation schedules and lower single doses also predispose to an inflammatory plaque phenotype. Methods and Materials: ApoE{sup -/-} mice were given 8 or 14 Gy, or 20 x 2.0 Gy in 4 weeks to the neck, and the carotid arteries were subsequently examinated for presence of atherosclerotic lesions, plaque size, and phenotype. Results: At 4 weeks, early atherosclerotic lesions were found in 44% of the mice after single doses of 14 Gy but not in age-matched controls. At 22 to 30 weeks after irradiation there was a twofold increase in the mean number of carotid lesions (8-14 Gy and 20 x 2.0 Gy) and total plaque burden (single doses only), compared with age-matched controls. The majority of lesions seen at 30 to 34 weeks after fractionated irradiation or 14-Gy single doses were granulocyte rich (100% and 63%, respectively), with thrombotic features (90% and 88%), whereas these phenotypes were much less common in age-matched controls or after a single dose of 8 Gy. Conclusions: We showed that fractionated irradiation accelerated the development of atherosclerosis in ApoE{sup -/-} mice and predisposed to the formation of an inflammatory, thrombotic plaque phenotype.

  9. Mitigation of radiation nephropathy after internal {alpha}-particle irradiation of kidneys

    SciTech Connect

    Jaggi, Jaspreet Singh; Seshan, Surya V.; McDevitt, Michael R.; Sgouros, George; Hyjek, Elizabeth; Scheinberg, David A. . E-mail: d-scheinberg@ski.mskcc.org

    2006-04-01

    Purpose: Internal irradiation of kidneys as a consequence of radioimmunotherapy, radiation accidents, or nuclear terrorism can result in radiation nephropathy. We attempted to modify pharmacologically, the functional and morphologic changes in mouse kidneys after injection with the actinium ({sup 225}Ac) nanogenerator, an in vivo generator of {alpha}- and {beta}-particle emitting elements. Methods and Materials: The animals were injected with 0.35 {mu}Ci of the {sup 225}Ac nanogenerator, which delivers a dose of 27.6 Gy to the kidneys. Then, they were randomized to receive captopril (angiotensin-converting enzyme inhibitor), L-158,809 (angiotensin II receptor-1 blocker), spironolactone (aldosterone receptor antagonist), or a placebo. Results: Forty weeks after the {sup 225}Ac injection, the placebo-control mice showed a significant increase in blood urea nitrogen (BUN) (87.6 {+-} 6.9 mg/dL), dilated Bowman spaces, and tubulolysis with basement membrane thickening. Captopril treatment accentuated the functional (BUN 119.0 {+-} 4.0 mg/dL; p <0.01 vs. placebo controls) and histopathologic damage. In contrast, L-158,809 offered moderate protection (BUN 66.6 {+-} 3.9 mg/dL; p = 0.02 vs. placebo controls). Spironolactone treatment, however, significantly prevented the development of histopathologic and functional changes (BUN 31.2 {+-} 2.5 mg/dL; p <0.001 vs. placebo controls). Conclusions: Low-dose spironolactone and, to a lesser extent, angiotensin receptor-1 blockade can offer renal protection in a mouse model of internal {alpha}-particle irradiation.

  10. Fractionated irradiation and early changes in salivary glands. Different effects on potassium efflux, exocytotic amylase release and gland morphology

    SciTech Connect

    Franzen, L.; Funegard, U.S.; Sundstroem, S.G.; Gustafsson, H.; Danielsson, A.; Henriksson, R. )

    1991-02-01

    Irradiation is a potent treatment modality of head and neck cancer. However, the irradiation is usually associated with an influence on salivary glands with ensuing dryness and discomfort for the patients. In the present study we used different in vitro secretory models and morphologic characterization of rat parotid gland. Radiation was given to one gland on a 5-day schedule with 6 MV photons (total dose 20, 30, 35, 40, 45 Gy). The contralateral gland served as control, and the analysis of glands were performed 10 days after the last irradiation treatment. The noradrenaline stimulated electrolyte secretion (86rubidium tracer for potassium) was decreased in relation to the irradiation dose and in comparison to contralateral control glands. Noradrenaline stimulated exocytotic amylase release was not affected by irradiation and, there were no signs of obvious quantitative morphologic alterations after irradiation compared with controls. The results suggest that there are differences in the sensitivity to radiation for the two different secretory processes in salivary glands, and, thus, the structures regulating electrolyte and fluid secretion seem to be more vulnerable to irradiation than the process of exocytosis. The results, however, do not allow discrimination between temporary cellular impairment and irreversible damage leading to cell death.

  11. Analysis of Leaf Area Index and Fraction of PAR Absorbed by Vegetation Products from the Terra MODIS Sensor: 2000-2005

    NASA Technical Reports Server (NTRS)

    Yang, Wenze; Huang, Dong; Tan, Bin; Stroeve, Julienne C.; Shabanov, Nikolay V.; Knyazikhin, Yuri; Nemani, Ramakrishna R.; Myneni, Ranga B.

    2006-01-01

    The analysis of two years of Collection 3 and five years of Collection 4 Terra Moderate Resolution Imaging Spectroradiometer (MODIS) Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) data sets is presented in this article with the goal of understanding product quality with respect to version (Collection 3 versus 4), algorithm (main versus backup), snow (snow-free versus snow on the ground), and cloud (cloud-free versus cloudy) conditions. Retrievals from the main radiative transfer algorithm increased from 55% in Collection 3 to 67% in Collection 4 due to algorithm refinements and improved inputs. Anomalously high LAI/FPAR values observed in Collection 3 product in some vegetation types were corrected in Collection 4. The problem of reflectance saturation and too few main algorithm retrievals in broadleaf forests persisted in Collection 4. The spurious seasonality in needleleaf LAI/FPAR fields was traced to fewer reliable input data and retrievals during the boreal winter period. About 97% of the snow covered pixels were processed by the backup Normalized Difference Vegetation Index-based algorithm. Similarly, a majority of retrievals under cloudy conditions were obtained from the backup algorithm. For these reasons, the users are advised to consult the quality flags accompanying the LAI and FPAR product.

  12. Ionizing radiation and autoimmunity: Induction of autoimmune disease in mice by high dose fractionated total lymphoid irradiation and its prevention by inoculating normal T cells

    SciTech Connect

    Sakaguchi, N.; Sakaguchi, S. Scripps Research Institute, La Jolla, CA PRESTO, JRDC, Institute of Phical and Chemical Research, Tsukuba, Ibaraki ); Miyai, K. )

    1992-11-01

    Ionizing radiation can functionally alter the immune system and break self-tolerance. High dose (42.5 Gy), fractionated (2.5 Gy 17 times) total lymphoid irradiation (TLI) on mice caused various organ-specific autoimmune diseases, such as gastritis, thyroiditis, and orchitis, depending on the radiation dosages, the extent of lymphoid irradiation, and the genetic background of the mouse strains. Radiation-induced tissue damage is not the primary cause of the autoimmune disease because irradiation of the target organs alone failed to elicit the autoimmunity and shielding of the organs from irradiation was unable to prevent it. In contrast, irradiation of both the thymus and the peripheral lymphoid organs/tissues was required for efficient induction of autoimmune disease by TLI. TLI eliminated the majority of mature thymocytes and the peripheral T cells for 1 mo, and inoculation of spleen cell, thymocyte, or bone marrow cell suspensions (prepared from syngeneic nonirradiated mice) within 2 wk after TLI effectively prevented the autoimmune development. Depletion of T cells from the inocula abrogated the preventive activity. CD4[sup +] T cells mediated the autoimmune prevention but CD8[sup +] T cells did not. CD4[sup +] T cells also appeared to mediate the TLI-induced autoimmune disease because CD4[sup +] T cells from disease-bearing TLI mice adoptively transferred the autoimmune disease to syngeneic naive mice. Taken together, these results indicate that high dose, fractionated ionizing radiation on the lymphoid organs/tissues can cause autoimmune disease by affecting the T cell immune system, rather than the target self-Ags, presumably by altering T cell-dependent control of self-reactive T cells. 62 refs., 9 figs., 2 tabs.

  13. Application of lumped-mass vibration absorber on the vibration reduction of a nonlinear beam-spring-mass system with internal resonances

    NASA Astrophysics Data System (ADS)

    Wang, Yi-Ren; Liang, Tzu-Wen

    2015-08-01

    The objective of this study was to optimize the damping effects of a lumped-mass vibration absorber (LMVA) attached to a hinged-hinged nonlinear beam held on a nonlinear elastic foundation. The LMVA was located at various points along the beam and supported by a spring from beneath. Analysis was performed on the internal resonance conditions with the aim of eliminating internal resonance and reducing the amplitude of vibrations in the beam by altering the location and mass of the LMVA as well as the spring constant. We employed the method of multiple scales (MOMS) for the analysis of frequency response in various modes. Fixed points plots were constructed and 3D maximum amplitude contour plots (3D MACPs) were compiled to identify the LMVA combinations with the optimal damping effects. The best damping results in the 3rd mode were achieved when the LMVA was placed between 1/4l and 1/2l in combinations of M^ (mass of LMVA/mass of beam) and K˜ (LMVA spring constant/elastic foundation spring constant) followed a linear relationship of K˜=10M^.

  14. Safety evaluation report related to the Department of Energy`s proposal for the irradiation of lead test assemblies containing tritium-producing burnable absorber rods in commercial light-water reactors. Project Number 697

    SciTech Connect

    1997-05-01

    The NRC staff has reviewed a report, submitted by DOE to determine whether the use of a commercial light-water reactor (CLWR) to irradiate a limited number of tritium-producing burnable absorber rods (TPBARs) in lead test assemblies (LTAs) raises generic issues involving an unreviewed safety question. The staff has prepared this safety evaluation to address the acceptability of these LTAs in accordance with the provision of 10 CFR 50.59 without NRC licensing action. As summarized in Section 10 of this safety evaluation, the staff has identified issues that require NRC review. The staff has also identified a number of areas in which an individual licensee undertaking irradiation of TPBAR LTAs will have to supplement the information in the DOE report before the staff can determine whether the proposed irradiation is acceptable at a particular facility. The staff concludes that a licensee undertaking irradiation of TPBAR LTAs in a CLWR will have to submit an application for amendment to its facility operating license before inserting the LTAs into the reactor.

  15. Effet de la dose d'irradiation sur la fraction tocophérolique d'huiles végétales

    NASA Astrophysics Data System (ADS)

    Chaouch, A.; El Fartah, S.; Pouliquen-Sonaglia, I.; Lesgards, G.; Raffi, J.; Trihi, M.

    1999-01-01

    Tocopherols, minor components of vegetable oils, are very important due to their high antioxydant power; we studied separation and quantification of tocopherol fraction with regard to the irradiation dose, using liquid chromatography combined with electrochemical detection. Dans les huiles végétales, les tocophérols sont des constituants mineurs très importants grâce à leur pouvoir antioxydant très élevé. Notre travail s'est porté sur la séparation et la quantification de la fraction tocophérolique et son évolution en fonction des différentes doses d'ionisation par la technique C.L.H.P. / détection électrochimique.

  16. Gamma-irradiation of liposomes composed of saturated phospholipids: effect of bilayer composition, size, concentration and absorbed dose on chemical degradation and physical destabilization of liposomes.

    PubMed

    Zuidam, N J; Versluis, C; Vernooy, E A; Crommelin, D J

    1996-04-01

    Liposomes composed of dipalmitoylphosphatidylcholine (DPPC), dipalmitoylphosphatidylglycerol (DPPG), or mixtures of these two phospholipids were exposed to gamma-irradiation in an air environment. Disappearance of the mother compounds was monitored by HPLC analysis. Plotting of the logarithmic values of residual DPPC or DPPG concentration versus irradiation dose resulted in straight lines. The slopes of these lines (overall degradation constants) depended on the type of phospholipids, concentration of the liposomes and the size of the liposomes. Under the chosen conditions, addition of DPPG in DPPC-liposomes did not affect the degradation rate constant of DPPC and vice versa. The presence of phosphate buffer (pH 7.4), pH or presence of sodium chloride did not affect the irradiation damage either. Minor changes were found upon analysis of total fatty acids by GLC and upon measurement of water soluble phosphate compounds. These changes were less pronounced than the changes monitored by HPLC of phospholipids, because the HPLC analysis monitored the overall degradation of the liposomal phospholipids. Thin-layer chromatography/fast atom bombardment mass spectrometry (TLC/FAB-MS) analysis of irradiated and non-irradiated DPPC or DPPG provided information on the structure of several degradation products. Degradation routes which include these degradation products are proposed. Gamma-irradiation neither affected the size of the liposomes nor the bilayer rigidity as determined by dynamic light scattering and fluorescence anisotropy of the probe 1,6-diphenyl-1,3,5-hexatriene (DPH), respectively. However, upon gamma-irradiation, changes in the melting characteristics of the liposomes were found by differential scanning calorimetry (DSC) measurements. The pre-transition melting enthalpy of the liposomal bilayer decreased or disappeared and the main-transition broadened. The changes found in DSC scans correlated qualitatively well with the changes recorded after HPLC analysis

  17. Radiation cross-linked carboxymethyl sago pulp hydrogels loaded with ciprofloxacin: Influence of irradiation on gel fraction, entrapped drug and in vitro release

    NASA Astrophysics Data System (ADS)

    Lam, Yi Lyn; Muniyandy, Saravanan; Kamaruddin, Hashim; Mansor, Ahmad; Janarthanan, Pushpamalar

    2015-01-01

    Carboxymethyl sago pulp (CMSP) with 0.4 DS, viscosity 184 dl/g and molecular weight 76,000 g/mol was synthesized from sago waste. 10 and 20% w/v solutions of CMSP were irradiated at 10-30 kGy to form hydrogels and were characterized by % gel fraction (GF). Irradiation of 20% CMSP using 25 kGy has produced stable hydrogels with the highest % GF and hence loaded with ciprofloxacin HCl. Drug-loaded hydrogels were produced by irradiating the mixture of drug and 20% CMSP solution at 25 kGy. After irradiation, the hydrogels were cut into circular discs with a diameter of 6±1 mm and evaluated for physicochemical properties as well as drug release kinetics. The ciprofloxacin loading in the disc was 14.7%±1 w/w with an entrapment efficiency of 73.5% w/w. The low standard deviation of drug-loaded discs indicated uniform thickness (1.5±0.3 mm). The unloaded discs were thinner (1±0.4 mm) and more brittle than the drug-loaded discs. FESEM, FT-IR, XRD, DSC and TGA analysis revealed the absence of polymer-drug interaction and transformation of crystalline to amorphous form of ciprofloxacin in the discs. The disc sustained the drug release in phosphate buffer pH 7.4 over 36 h in a first-order manner. The mechanism of the drug release was found to be swelling controlled diffusion and matrix erosion. The anti-bacterial effect of ciprofloxacin was retained after irradiation and CMSP disc could be a promising device for ocular drug delivery.

  18. IFMIF, International Fusion Materials Irradiation Facility conceptual design activity cost report

    SciTech Connect

    Rennich, M.J.

    1996-12-01

    This report documents the cost estimate for the International Fusion Materials Irradiation Facility (IFMIF) at the completion of the Conceptual Design Activity (CDA). The estimate corresponds to the design documented in the Final IFMIF CDA Report. In order to effectively involve all the collaborating parties in the development of the estimate, a preparatory meeting was held at Oak Ridge National Laboratory in March 1996 to jointly establish guidelines to insure that the estimate was uniformly prepared while still permitting each country to use customary costing techniques. These guidelines are described in Section 4. A preliminary cost estimate was issued in July 1996 based on the results of the Second Design Integration Meeting, May 20--27, 1996 at JAERI, Tokai, Japan. This document served as the basis for the final costing and review efforts culminating in a final review during the Third IFMIF Design Integration Meeting, October 14--25, 1996, ENEA, Frascati, Italy. The present estimate is a baseline cost estimate which does not apply to a specific site. A revised cost estimate will be prepared following the assignment of both the site and all the facility responsibilities.

  19. The melanosome: threshold temperature for explosive vaporization and internal absorption coefficient during pulsed laser irradiation.

    PubMed

    Jacques, S L; McAuliffe, D J

    1991-06-01

    The explosive vaporization of melanosomes in situ in skin during pulsed laser irradiation (pulse duration less than 1 microsecond) is observed as a visible whitening of the superficial epidermal layer due to stratum corneum disruption. In this study, the ruby laser (694 nm) was used to determine the threshold radiant exposure, H0 (J/cm2), required to elicit whitening for in vitro black (Negroid) human skin samples which were pre-equilibrated at an initial temperature, Ti, of 0, 20, or 50 degrees C. A plot of H0 vs Ti yields a straight line whose x-intercept indicates the threshold temperature of explosive vaporization to be 112 +/- 7 degrees C (SD, N = 3). The slope, delta H0/delta Ti, specifies the internal absorption coefficient, mua, within the melanosome: mua = -rho C/(slope(1 + 7.1 Rd)), where rho C is the product of density and specific heat, and Rd is the total diffuse reflectance from the skin. A summary of the absorption spectrum (mua) for the melanosome interior (351-1064 nm) is presented based on H0 data from this study and the literature. The in vivo absorption spectrum (380-820 nm) for human epidermal melanin was measured by an optical fiber spectrophotometer and is compared with the melanosome spectrum. PMID:1886936

  20. Segmented Ge detector rejection of internal beta activity produced by neutron irradiation

    NASA Technical Reports Server (NTRS)

    Varnell, L. S.; Callas, J. L.; Mahoney, W. A.; Pehl, R. H.; Landis, D. A.

    1991-01-01

    Future Ge spectrometers flown in space to observe cosmic gamma-ray sources will incorporate segmented detectors to reduce the background from radioactivity produced by energetic particle reactions. To demonstrate the effectiveness of a segmented Ge detector in rejecting background events due to the beta decay of internal radioactivity, a laboratory experiment has been carried out in which radioactivity was produced in the detector by neutron irradiation. A Cf-252 source of neutrons was used to produce, by neutron capture on Ge-74 (36.5 percent of natural Ge) in the detector itself, Ge-75 (t sub 1/2 = 82.78 min), which decays by beta emission with a maximum electron kinetic energy of 1188 keV. By requiring that an ionizing event deposit energy in two or more of the five segments of the detector, each about 1-cm thick, the beta particles, which have a range of about 1-mm, are rejected, while most external gamma rays incident on the detector are counted. Analysis of this experiment indicates that over 85 percent of the beta events from the decay of Ge-75 are rejected, which is in good agreement with Monte Carlo calculations.

  1. High Levels of Dietary Supplement Vitamins A, C and E are Absorbed in the Small Intestine and Protect Nutrient Transport Against Chronic Gamma Irradiation.

    PubMed

    Roche, Marjolaine; Neti, Prasad V S V; Kemp, Francis W; Azzam, Edouard I; Ferraris, Ronaldo P; Howell, Roger W

    2015-11-01

    We examined nutrient transport in the intestines of mice exposed to chronic low-LET 137Cs gamma rays. The mice were whole-body irradiated for 3 days at dose rates of 0, 0.13 and 0.20 Gy/h, for total dose delivery of 0, 9.6 or 14.4 Gy, respectively. The mice were fed either a control diet or a diet supplemented with high levels of vitamins A, C and E. Our results showed that nutrient transport was perturbed by the chronic irradiation conditions. However, no apparent alteration of the macroscopic intestinal structures of the small intestine were observed up to day 10 after initiating irradiation. Jejunal fructose uptake measured in vitro was strongly affected by the chronic irradiation, whereas uptake of proline, carnosine and the bile acid taurocholate in the ileum was less affected. D-glucose transport did not appear to be inhibited significantly by either 9.6 or 14.4 Gy exposure. In the 14.4 Gy irradiated groups, the diet supplemented with high levels of vitamins A, C and E increased intestinal transport of fructose compared to the control diet (day 10; t test, P = 0.032), which correlated with elevated levels of vitamins A, C and E in the plasma and jejunal enterocytes. Our earlier studies with mice exposed acutely to 137Cs gamma rays demonstrated significant protection for transport of fructose, glucose, proline and carnosine. Taken together, these results suggest that high levels of vitamins A, C and E dietary supplements help preserve intestinal nutrient transport when intestines are irradiated chronically or acutely with low-LET gamma rays. PMID:26484399

  2. International Fusion Materials Irradiation Facility injector acceptance tests at CEA/Saclay: 140 mA/100 keV deuteron beam characterization.

    PubMed

    Gobin, R; Bogard, D; Cara, P; Chauvin, N; Chel, S; Delferrière, O; Harrault, F; Mattei, P; Mosnier, A; Senée, F; Shidara, H; Okumura, Y

    2014-02-01

    In the framework of the ITER broader approach, the International Fusion Materials Irradiation Facility (IFMIF) deuteron accelerator (2 × 125 mA at 40 MeV) is an irradiation tool dedicated to high neutron flux production for future nuclear plant material studies. During the validation phase, the Linear IFMIF Prototype Accelerator (LIPAc) machine will be tested on the Rokkasho site in Japan. This demonstrator aims to produce 125 mA/9 MeV deuteron beam. Involved in the LIPAc project for several years, specialists from CEA/Saclay designed the injector based on a SILHI type ECR source operating at 2.45 GHz and a 2 solenoid low energy beam line to produce such high intensity beam. The whole injector, equipped with its dedicated diagnostics, has been then installed and tested on the Saclay site. Before shipment from Europe to Japan, acceptance tests have been performed in November 2012 with 100 keV deuteron beam and intensity as high as 140 mA in continuous and pulsed mode. In this paper, the emittance measurements done for different duty cycles and different beam intensities will be presented as well as beam species fraction analysis. Then the reinstallation in Japan and commissioning plan on site will be reported. PMID:24593497

  3. Three-year outcomes of a once daily fractionation scheme for accelerated partial breast irradiation (APBI) using 3-D conformal radiotherapy (3D-CRT)

    PubMed Central

    Goyal, Sharad; Daroui, Parima; Khan, Atif J; Kearney, Thomas; Kirstein, Laurie; Haffty, Bruce G

    2013-01-01

    The aim of this study was to report 3-year outcomes of toxicity, cosmesis, and local control using a once daily fractionation scheme (49.95 Gy in 3.33 Gy once daily fractions) for accelerated partial breast irradiation (APBI) using three-dimensional conformal radiotherapy (3D-CRT). Between July 2008 and August 2010, women aged ≥40 years with ductal carcinoma in situ or node-negative invasive breast cancer ≤3 cm in diameter, treated with breast-conserving surgery achieving negative margins, were accrued to a prospective study. Women were treated with APBI using 3–5 photon beams, delivering 49.95 Gy over 15 once daily fractions over 3 weeks. Patients were assessed for toxicities, cosmesis, and local control rates before APBI and at specified time points. Thirty-four patients (mean age 60 years) with Tis 0 (n = 9) and T1N0 (n = 25) breast cancer were treated and followed up for an average of 39 months. Only 3% (1/34) patients experienced a grade 3 subcutaneous fibrosis and breast edema and 97% of the patients had good/excellent cosmetic outcome at 3 years. The 3-year rate of ipsilateral breast tumor recurrence (IBTR) was 0% while the rate of contralateral breast events was 6%. The 3-year disease-free survival (DFS), overall survival (OS), and breast cancer-specific survival (BCSS) was 94%, 100%, and 100%, respectively. Our novel accelerated partial breast fractionation scheme of 15 once daily fractions of 3.33 Gy (49.95 Gy total) is a remarkably well-tolerated regimen of 3D-CRT-based APBI. A larger cohort of patients is needed to further ascertain the toxicity of this accelerated partial breast regimen. PMID:24403270

  4. Explication of Definitional Description and Empirical Use of Fraction of Orally Administered Drugs Absorbed From the Intestine (Fa) and Intestinal Availability (Fg): Effect of P-glycoprotein and CYP3A on Fa and Fg.

    PubMed

    Tanaka, Yuta; Kitamura, Yoshiaki; Maeda, Kazuya; Sugiyama, Yuichi

    2016-02-01

    Conventionally, it is believed that the fraction of orally administered drugs absorbed from the intestine (Fa) and intestinal availability (Fg) are independently determined by the apical membrane permeation and intestinal metabolism, respectively. However, the validity of this belief has not been well discussed, and Fa and Fg are often used without careful definition. In this review, Fa and Fg are mathematically described based on their definitions under the linear kinetics of metabolism and transport. Even considering with different models, intestinal metabolic enzymes such as cytochrome P450 3A affected both Fa and Fg, whereas apical efflux transporters including P-glycoprotein had no influence on Fg at least under the linear condition. To determine whether Fa and Fg calculated using different clinical methods are identical, empirical Fa and Fg were mathematically described based on "feces method" and "grapefruit juice method" and compared with their definitions. Fa and Fg obtained by the feces method corresponded with their definitions whereas the grapefruit juice method provided smaller Fa and larger Fg particularly for dual substrates of P-glycoprotein and cytochrome P450 3A with low membrane permeability. Our analyses suggest that the definitions and calculation methods of Fa and Fg should be considered when we intend to separately determine these values. PMID:26869410

  5. Absolute Cavity Pyrgeometer to Measure the Absolute Outdoor Longwave Irradiance with Traceability to International System of Units, SI

    SciTech Connect

    Reda, I.; Zeng, J.; Scheuch, J.; Hanssen, L.; Wilthan, B.; Myers, D.; Stoffel, T.

    2012-03-01

    This article describes a method of measuring the absolute outdoor longwave irradiance using an absolute cavity pyrgeometer (ACP), U.S. Patent application no. 13/049, 275. The ACP consists of domeless thermopile pyrgeometer, gold-plated concentrator, temperature controller, and data acquisition. The dome was removed from the pyrgeometer to remove errors associated with dome transmittance and the dome correction factor. To avoid thermal convection and wind effect errors resulting from using a domeless thermopile, the gold-plated concentrator was placed above the thermopile. The concentrator is a dual compound parabolic concentrator (CPC) with 180{sup o} view angle to measure the outdoor incoming longwave irradiance from the atmosphere. The incoming irradiance is reflected from the specular gold surface of the CPC and concentrated on the 11 mm diameter of the pyrgeometer's blackened thermopile. The CPC's interior surface design and the resulting cavitation result in a throughput value that was characterized by the National Institute of Standards and Technology. The ACP was installed horizontally outdoor on an aluminum plate connected to the temperature controller to control the pyrgeometer's case temperature. The responsivity of the pyrgeometer's thermopile detector was determined by lowering the case temperature and calculating the rate of change of the thermopile output voltage versus the changing net irradiance. The responsivity is then used to calculate the absolute atmospheric longwave irradiance with an uncertainty estimate (U{sub 95}) of {+-}3.96 W m{sup 02} with traceability to the International System of Units, SI. The measured irradiance was compared with the irradiance measured by two pyrgeometers calibrated by the World Radiation Center with traceability to the Interim World Infrared Standard Group, WISG. A total of 408 readings were collected over three different nights. The calculated irradiance measured by the ACP was 1.5 W/m{sup 2} lower than that

  6. An absolute cavity pyrgeometer to measure the absolute outdoor longwave irradiance with traceability to international system of units, SI

    NASA Astrophysics Data System (ADS)

    Reda, Ibrahim; Zeng, Jinan; Scheuch, Jonathan; Hanssen, Leonard; Wilthan, Boris; Myers, Daryl; Stoffel, Tom

    2012-03-01

    This article describes a method of measuring the absolute outdoor longwave irradiance using an absolute cavity pyrgeometer (ACP), U.S. Patent application no. 13/049, 275. The ACP consists of domeless thermopile pyrgeometer, gold-plated concentrator, temperature controller, and data acquisition. The dome was removed from the pyrgeometer to remove errors associated with dome transmittance and the dome correction factor. To avoid thermal convection and wind effect errors resulting from using a domeless thermopile, the gold-plated concentrator was placed above the thermopile. The concentrator is a dual compound parabolic concentrator (CPC) with 180° view angle to measure the outdoor incoming longwave irradiance from the atmosphere. The incoming irradiance is reflected from the specular gold surface of the CPC and concentrated on the 11 mm diameter of the pyrgeometer's blackened thermopile. The CPC's interior surface design and the resulting cavitation result in a throughput value that was characterized by the National Institute of Standards and Technology. The ACP was installed horizontally outdoor on an aluminum plate connected to the temperature controller to control the pyrgeometer's case temperature. The responsivity of the pyrgeometer's thermopile detector was determined by lowering the case temperature and calculating the rate of change of the thermopile output voltage versus the changing net irradiance. The responsivity is then used to calculate the absolute atmospheric longwave irradiance with an uncertainty estimate (U95) of ±3.96 W m-2 with traceability to the International System of Units, SI. The measured irradiance was compared with the irradiance measured by two pyrgeometers calibrated by the World Radiation Center with traceability to the Interim World Infrared Standard Group, WISG. A total of 408 readings were collected over three different nights. The calculated irradiance measured by the ACP was 1.5 W/m2 lower than that measured by the two

  7. The Sun as a variable star: Solar and stellar irradiance variations; Colloquium of the International Astronomical Union, 143rd, Boulder, CO, Jun. 20-25, 1993

    NASA Technical Reports Server (NTRS)

    Pap, Judit M. (Editor); Froehlich, Claus (Editor); Hudson, Hugh S. (Editor); Tobiska, W. Kent (Editor)

    1994-01-01

    Variations in solar and stellar irradiances have long been of interest. An International Astronomical Union (IAU) colloquium reviewed such relevant subjects as observations, theoretical interpretations, and empirical and physical models, with a special emphasis on climatic impact of solar irradiance variability. Specific topics discussed included: (1) General Reviews on Observations of Solar and Stellar Irradiance Variability; (2) Observational Programs for Solar and Stellar Irradiance Variability; (3) Variability of Solar and Stellar Irradiance Related to the Network, Active Regions (Sunspots and Plages), and Large-Scale Magnetic Structures; (4) Empirical Models of Solar Total and Spectral Irradiance Variability; (5) Solar and Stellar Oscillations, Irradiance Variations and their Interpretations; and (6) The Response of the Earth's Atmosphere to Solar Irradiance Variations and Sun-Climate Connections.

  8. Effect of neutron irradiation on tensile properties of materials for pressure vessel internals of WWER type reactors

    NASA Astrophysics Data System (ADS)

    Sorokin, A. A.; Margolin, B. Z.; Kursevich, I. P.; Minkin, A. J.; Neustroev, V. S.

    2014-01-01

    Tensile properties of austenitic stainless steels used for pressure vessel internals of WWER type reactors (18Cr-10Ni-Ti steel and its weld metal) in the initial and irradiated conditions were investigated. Based on the presented original investigations and generalization of the available experimental data the dependences of yield strength and ultimate strength on a neutron damage dose up to 108 dpa, irradiation temperature range 320-450 °C and test temperature range 20-450 °C were obtained. The method of determination of the stress-strain curve parameters was proposed which does not require uniform elongation of a specimen as an input parameter. The dependences was proposed allowing one to calculate the stress-strain curve parameters for 18Cr-10Ni-Ti steel and its weld metal for different test temperatures, different irradiation temperatures and doses. The dependences were obtained to describe the fracture strain decrease under irradiation at a temperature range 320-340 °C when irradiation swelling is absent.

  9. Post-irradiation effects in polyethylenes irradiated under various atmospheres

    NASA Astrophysics Data System (ADS)

    Suljovrujic, E.

    2013-08-01

    If a large amount of polymer free radicals remain trapped after irradiation of polymers, the post-irradiation effects may result in a significant alteration of physical properties during long-term shelf storage and use. In the case of polyethylenes (PEs) some failures are attributed to the post-irradiation oxidative degradation initiated by the reaction of residual free radicals (mainly trapped in crystal phase) with oxygen. Oxidation products such as carbonyl groups act as deep traps and introduce changes in carrier mobility and significant deterioration in the PEs electrical insulating properties. The post-irradiation behaviour of three different PEs, low density polyethylene (LDPE), linear low density polyethylene (LLDPE) and high density polyethylene (HDPE) was studied; previously, the post-irradiation behaviour of the PEs was investigated after the irradiation in air (Suljovrujic, 2010). In this paper, in order to investigate the influence of different irradiation media on the post-irradiation behaviour, the samples were irradiated in air and nitrogen gas, to an absorbed dose of 300 kGy. The annealing treatment of irradiated PEs, which can substantially reduce the concentration of free radicals, is used in this study, too. Dielectric relaxation behaviour is related to the difference in the initial structure of PEs (such as branching, crystallinity etc.), to the changes induced by irradiation in different media and to the post-irradiation changes induced by storage of the samples in air. Electron spin resonance (ESR), differential scanning calorimetry (DSC), infra-red (IR) spectroscopy and gel measurements were used to determine the changes in the free radical concentration, crystal fraction, oxidation and degree of network formation, respectively.

  10. Multiple Types of Light Absorbing Carbon Aerosol in East Asian Outflow: Variatons in Morphology and Internal Structure as Characterized by Transmission Electron Microscopy

    NASA Astrophysics Data System (ADS)

    Anderson, J. R.; Alexander, D. T.; Crozier, P. A.

    2010-12-01

    The importance of light absorbing carbon (LAC) aerosols to climate forcing is well established, but such aerosols are typically treated in climate models as uniform in optical properties. When examined by electron microscopy, however, LAC aerosols from regions with significant anthropogenic pollution show a wide variety of morphologies and internal structures. Electron energy loss spectral analysis to date on brown carbon and black carbon, albeit limited, suggests a linkage between internal structure and fundamental optical properties. Some of these LAC varieties can be easily defined as distinct “types” and other varieties show a continuum of variation within which general “types” can be defined. The data discussed here are from a research flight of the NCAR C-130 aircraft flown in April 2001 above the Yellow Sea during the ACE-Asia project. Perhaps the most common LAC type is “soot”, branched and chainlike aggregates of carbonaceous spherules. The spherule size in East Asian soot particles is 20-60 nm in many cases, but soot with large spherules (100 nm or larger) are also present. Spherule size is a “source effect” and not something altered during transport and aging. Some laboratory studies have suggested that as soot ages, the aggregates become more compact, but in these aerosols both compact and open soot particles coexist and compact soot is known to be the initial LAC product under some combustion conditions. In cases where the spherule size of the compact soot is different from that of open-structured soot, clearly the compact soot is not an aged form of the latter. Variability of ordering of the graphene sheets that make up the spherules is also a source effect. The more ordered soot particles consist of graphene sheets that curve concentrically, onion-like, around the spherule center, probably indicative of a high degree of carbonization that accompanies high temperature combustion. There is a range of ordering from highly ordered down to

  11. A practical alpha particle irradiator for studying internal alpha particle exposure.

    PubMed

    Lee, Ki-Man; Lee, Ui-Seob; Kim, Eun-Hee

    2016-09-01

    An alpha particle irradiator has been built in the Radiation Bioengineering Laboratory at Seoul National University (SNU) to investigate the cellular responses to alpha emissions from radon and the progeny. This irradiator is designed to have the energy of alpha particles entering target cells similar to that of alpha emissions from the radon progeny Po-218 and Po-214 residing in the human respiratory tract. For the SNU alpha particle irradiator, an irradiation system is equipped with cell dishes of 4µm thick Mylar bottom and a special setup of cells on slide for gamma-H2AX assay. Dose calibration for the alpha particle irradiator was performed by dual approaches, detection and computer simulation, in consideration of the source-to-target distance (STD) and the size of a cell dish. The uniformity of dose among cells in a dish is achieved by keeping the STD and the size of cell dish in certain ranges. The performance of the SNU alpha particle irradiator has been proven to be reliable through the gamma-H2AX assay with the human lung epithelial cells irradiated. PMID:27475622

  12. Photocatalytic CO2 reduction over B4C/C3N4 with internal electric field under visible light irradiation.

    PubMed

    Zhang, Xiaojie; Wang, Lei; Du, Quanchao; Wang, Zhiyong; Ma, Shuguo; Yu, Miao

    2016-02-15

    Boron carbide/graphitic carbon nitride (B4C/g-C3N4) p-n hetero-junction photocatalyst with an internal electric field was synthesized by a facile solvent evaporation method and characterized by field emission scanning electron microscope (FESEM), UV-Vis diffuse reflectance spectra (UV-Vis DRS), photoluminescence spectra (PL), etc. Photocatalytic activity of the composite B4C/g-C3N4 loaded with Pt co-catalyst was evaluated using CO2 conversion to CH4 with H2 as the hydrogen source and reductant under visible light irradiation. The coupling of p-type B4C with n-type g-C3N4 significantly improved the performance of photocatalytic CO2 reduction; with the optimum B4C mass fraction of 1/6, the composite photocatalyst showed approximately 6 and 8 times higher CH4 generation rate than g-C3N4 and B4C, respectively. The enhancement was attributed to efficient photo-excited electron/hole separation due to the formation of internal electric field at the p-B4C/n-C3N4 interface. PMID:26609927

  13. T-cell differentation in lethally irradiated and reconstituted mice: functional recovery of PNA-fractionated subpopulations. [X ray

    SciTech Connect

    Kraal, G.; Groeneveld, P.H.P.; Boden, D.; Kors, N.

    1981-07-15

    In mammals T lymphocytes are generated in the thymus from hemopoietic precursor cells. The thymus is able to instruct the T cells during their differentiation resulting in functionally different subpopulations which can leave the thymus for the peripheral lymphoid organs. These functionally different T-cell subpopulations have been described using the alloantigens Ly-1, 2, and 3. Another probe to study thymus subpopulations is the use of the nonmitogenic lectin peanut agglutinin (PNA). After lethal irradiation and reconsitution (IR) there is a 6-day lag before thymus cells start to proliferate. In the first 6 days there is a relative enrichment of PNA-negative cells, which are Ly-1/sup +/ and radioresistant. After IR the mitogenic responses of the PNA-negative cells recover earlier than those of the PNA-positive cells; the implications of this finding for different T-cell lineages are discussed.

  14. Determination of oxygen extraction fraction using magnetic resonance imaging in canine models with internal carotid artery occlusion

    PubMed Central

    Chang, Fei-Yan; Xiao, Jiang-Xi; Xie, Sheng; Yu, Lei; Zhang, Zhen-Xia; Wang, Wu; Luo, Jie; Zhang, Zhong-Ping; Guo, Hua

    2016-01-01

    Perfusion of the penumbra tissue below the flow threshold for functional disturbance but above that for the maintenance of morphological integrity is the target for therapy in acute ischaemic stroke. The measurement of the oxygen extraction fraction (OEF) may provide a direct assessment of tissue viability, so that irreversible tissue damage and penumbra can be reliably identified. By using an asymmetric spin echo single-shot echo planar imaging (ASE-SSEPI) sequence, the quantitative OEF was obtained in the ischaemic brain tissues of canine models with internal carotid artery occlusion. TTC staining, which delineated the regions of infarct and penumbra, was used for defining the corresponding regions on OEF maps. The threshold of the OEF to discriminate the infarct cores and penumbral tissues was then determined according to the OEF values at different times. With repeated-measures ANOVA, the OEF of the infarcted regions was found to be time dependent. An OEF greater than 0.48 best predicted cortical infarction at 1.5 hr, with an area under the receiving operating characteristic curve of 0.968, a sensitivity of 97.5%, and a specificity of 92.5%. Our results may be helpful in the evaluation of tissue viability during stroke events. PMID:27443195

  15. Determination of oxygen extraction fraction using magnetic resonance imaging in canine models with internal carotid artery occlusion.

    PubMed

    Chang, Fei-Yan; Xiao, Jiang-Xi; Xie, Sheng; Yu, Lei; Zhang, Zhen-Xia; Wang, Wu; Luo, Jie; Zhang, Zhong-Ping; Guo, Hua

    2016-01-01

    Perfusion of the penumbra tissue below the flow threshold for functional disturbance but above that for the maintenance of morphological integrity is the target for therapy in acute ischaemic stroke. The measurement of the oxygen extraction fraction (OEF) may provide a direct assessment of tissue viability, so that irreversible tissue damage and penumbra can be reliably identified. By using an asymmetric spin echo single-shot echo planar imaging (ASE-SSEPI) sequence, the quantitative OEF was obtained in the ischaemic brain tissues of canine models with internal carotid artery occlusion. TTC staining, which delineated the regions of infarct and penumbra, was used for defining the corresponding regions on OEF maps. The threshold of the OEF to discriminate the infarct cores and penumbral tissues was then determined according to the OEF values at different times. With repeated-measures ANOVA, the OEF of the infarcted regions was found to be time dependent. An OEF greater than 0.48 best predicted cortical infarction at 1.5 hr, with an area under the receiving operating characteristic curve of 0.968, a sensitivity of 97.5%, and a specificity of 92.5%. Our results may be helpful in the evaluation of tissue viability during stroke events. PMID:27443195

  16. Comparison between absorbed dose to water standards established by water calorimetry at the LNE-LNHB and by application of international air-kerma based protocols for kilovoltage medium energy x-rays

    NASA Astrophysics Data System (ADS)

    Perichon, N.; Rapp, B.; Denoziere, M.; Daures, J.; Ostrowsky, A.; Bordy, J.-M.

    2013-05-01

    Nowadays, the absorbed dose to water for kilovoltage x-ray beams is determined from standards in terms of air-kerma by application of international dosimetry protocols. New standards in terms of absorbed dose to water has just been established for these beams at the LNE-LNHB, using water calorimetry, at a depth of 2 cm in water in accordance with protocols. The aim of this study is to compare these new standards in terms of absorbed dose to water, to the dose values calculated from the application of four international protocols based on air-kerma standards (IAEA TRS-277, AAPM TG-61, IPEMB and NCS-10). The acceleration potentials of the six beams studied are between 80 and 300 kV with half-value layers between 3.01 mm of aluminum and 3.40 mm of copper. A difference between the two methods smaller than 2.1% was reported. The standard uncertainty of water calorimetry being below 0.8%, and the one associated with the values from protocols being around 2.5%, the results are in good agreement. The calibration coefficients of some ionization chambers in terms of absorbed dose to water, established by application of calorimetry and air-kerma based dosimetry protocols, were also compared. The best agreement with the calibration coefficients established by water calorimetry was found for those established with the AAPM TG-61 protocol.

  17. Using EO-1 Hyperion to Simulate HyspIRI Products for a Coniferous Forest: The Fraction of PAR Absorbed by Chlorophyll (fAPAR(sub chl)) and Leaf Water Content (LWC)

    NASA Technical Reports Server (NTRS)

    Zhang, Qingyuan; Middleton, Elizabeth M.; Gao, Bo-Cai; Cheng, Yen-Ben

    2011-01-01

    This study presents development of prototype products for terrestrial ecosystems in preparation for the future imaging spectrometer planned for the Hyperspectral Infrared Imager (HyspIRI) mission. We present a successful demonstration example in a coniferous forest of two product prototypes: fraction of photosynthetic active radiation (PAR) absorbed by chlorophyll of a canopy (fAPAR(sub chl)) and leaf water content (LWC), for future HyspIRI implementation at 60 m spatial resolution. For this, we used existing 30 m resolution imaging spectrometer data available from the Earth Observing One (EO-1) Hyperion satellite to simulate and prototype the level one radiometrically corrected radiance (L1R) images expected from the HyspIRI visible through shortwave infrared spectrometer. The HyspIRI-like images were atmospherically corrected to obtain surface reflectance, and spectrally resampled to produce 60 m reflectance images for wavelength regions that were comparable to all seven of the MODerate resolution Imaging Spectroradiometer (MODIS) land bands. Thus, we developed MODIS-like surface reflectance in seven spectral bands at the HyspIRI-like spatial scale, which was utilized to derive fAPARchl and LWC with a coupled canopy-leaf radiative transfer model (PROSAIL2) for the coniferous forest[1]. With this study, we provide additional evidence that the fAPARchl product is more realistic for describing the physiologically active canopy than the traditional fAPAR parameter for the whole canopy (fAPAR(sub canopy)), and thus should replace it in ecosystem process models to reduce uncertainties in terrestrial carbon cycle studies and ecosystem studies.

  18. Using EO-1 Hyperion to Simulate HyspIRI Products for a Coniferous Forest: The Fraction of PAR Absorbed by Chlorophyll (fAPAR(sub chl)) and Leaf Water Content(LWC)

    NASA Technical Reports Server (NTRS)

    Zhang, Qingyuan; Middleton, Elizabeth M.; Gao, Bo-Cai; Cheng, Yen-Ben

    2012-01-01

    This paper presents development of prototype products for terrestrial ecosystems in preparation for the future imaging spectrometer planned for the Hyperspectral Infrared Imager (HyspIRI) mission. We present a successful demonstration example in a coniferous forest of two product prototypes: fraction of photosynthetically active radiation (PAR) absorbed by chlorophyll of a canopy (fAPARchl) and leaf water content (LWC), for future HyspIRI implementation at 60-m spatial resolution. For this, we used existing 30-m resolution imaging spectrometer data available from the Earth Observing One (EO-1) Hyperion satellite to simulate and prototype the level one radiometrically corrected radiance (L1R) images expected from the HyspIRI visible through shortwave infrared spectrometer. The HyspIRIlike images were atmospherically corrected to obtain surface reflectance and spectrally resampled to produce 60-m reflectance images for wavelength regions that were comparable to all seven of the MODerate resolution Imaging Spectroradiometer (MODIS) land bands. Thus, we developed MODIS-like surface reflectance in seven spectral bands at the HyspIRI-like spatial scale, which was utilized to derive fAPARchl and LWC with a coupled canopy-leaf radiative transfer model (PROSAIL2) for the coniferous forest. With this paper, we provide additional evidence that the fAPARchl product is more realistic in describing the physiologically active canopy than the traditional fAPAR parameter for the whole canopy (fAPARcanopy), and thus, it should replace it in ecosystem process models to reduce uncertainties in terrestrial carbon cycle and ecosystem studies.

  19. Phase 2 Trial of Accelerated, Hypofractionated Whole-Breast Irradiation of 39 Gy in 13 Fractions Followed by a Tumor Bed Boost Sequentially Delivering 9 Gy in 3 Fractions in Early-Stage Breast Cancer

    SciTech Connect

    Kim, Ja Young; Jung, So-Youn; Lee, Seeyoun; Kang, Han-Sung; Lee, Eun Sook; Park, In Hae; Lee, Keun Seok; Ro, Jungsil; Lee, Nam Kwon; Shin, Kyung Hwan

    2013-12-01

    Purpose: To report a phase 2 trial of accelerated, hypofractionated whole-breast irradiation (AH-WBI) delivered as a daily dose of 3 Gy to the whole breast followed by a tumor bed boost. Methods and Materials: Two hundred seventy-six patients diagnosed with breast cancer (pT1-2 and pN0-1a) who had undergone breast-conserving surgery in which the operative margins were negative were treated with AH-WBI delivered as 39 Gy in 13 fractions of 3 Gy to the whole breast once daily over 5 consecutive working days, and 9 Gy in 3 sequential fractions of 3 Gy to a lumpectomy cavity, all within 3.2 weeks. Results: After a median follow-up period of 57 months (range: 27-75 months), the rate of 5-year locoregional recurrence was 1.4% (n=4), whereas that of disease-free survival was 97.4%. No grade 3 skin toxicity was reported during the follow-up period. Qualitative physician cosmetic assessments of good or excellent were noted in 82% of the patients at 2 months after the completion of AH-WBI. The global cosmetic outcome did not worsen over time, and a good or excellent cosmetic outcome was reported in 82% of the patients at 3 years. The mean pretreatment percentage breast retraction assessment was 12.00 (95% confidence interval [CI]: 11.14-12.86). The mean value of percentage breast retraction assessment increased to 13.99 (95% CI: 12.17-15.96) after 1 year and decreased to 13.54 (95% CI: 11.84-15.46) after 3 years but was not significant (P>.05). Conclusions: AH-WBI consisting of 39 Gy in 13 fractions followed by a tumor bed boost sequentially delivering 9 Gy in 3 fractions can be delivered with excellent disease control and tolerable skin toxicity in patients with early-stage breast cancer after breast-conserving surgery.

  20. Initiation stress threshold irradiation assisted stress corrosion cracking criterion assessment for core internals in PWR environment

    SciTech Connect

    Tanguy, Benoit; Stern, Anthony; Bossis, Philippe; Pokor, Cedric

    2012-07-01

    Irradiation assisted stress corrosion cracking (IASCC) is a problem of growing importance in pressurized water reactors (PWR). An understanding of the mechanism(s) of IASCC is required in order to provide guidance for the development of mitigation strategies. One of the principal reasons why the IASCC mechanism(s) has been so difficult to understand is the inseparability of the different IASCC potential contributors evolutions due to neutron irradiation. The potential contributors to IASCC in PWR primary water are: (i) radiation induced segregation (RIS) at grain boundaries, (ii) radiation induced microstructure (formation and growth of dislocations loops, voids, bubbles, phases), (iii) localized deformation under loading, (iv) irradiation creep and transmutations. While the development of some of the contributors (RIS, microstructure) with increasing doses are at least qualitatively well understood, the role of these changes on IASCC remains unclear. Parallel to fundamental understanding developments relative to IASCC, well controlled laboratory tests on neutron irradiated stainless steels are needed to assess the main mechanisms and also to establish an engineering criterion relative to the initiation of fracture due to IASCC. First part of this study describes the methodology carried out at CEA in order to provide more experimental data from constant load tests dedicated to the study of initiation of SCC on neutron irradiated stainless steel. A description of the autoclave recirculation loop dedicated to SCC tests on neutron irradiated materials is then given. This autoclave recirculation loop has been started on July 2010 with the first SCC test on an irradiated stainless steel (grade 316) performed at CEA. The main steps of the interrupted SCC tests are then described. Second part of this paper reports the partial results of the first test performed on a highly neutron irradiated material. (authors)

  1. Prospective randomized study of various irradiation doses and fractionation schedules in the treatment of inoperable non-oat-cell carcinoma of the lung

    SciTech Connect

    Perez, C.A.; Stanley, K.; Rubin, P.; Kramer, S.; Brady, L.; Perez-Tamayo, R.; Brown, G.S.; Concannon, J.; Rotman, M.; Seydel, H.G.

    1980-06-01

    Analysis is presented of a prospective randomized study involving 365 patients with histologically proven unresectable non-oat-cell carcinoma of the lung treated with deffinitive radiotherapy. The patients were radomized to one of four treatment regimens: 4000 rad split course, or 4000, 5000, or 6000-rad continuous courses in five fractions per week. Ninety to 100 patients were accessioned to each group. The one-year survival rate is 50% and the two-year survival rate, 25%. The patients treated with the split course have the lowest survival rate in comparison with the other groups. The complete and partial local regression of tumor was 49% in patients treated with 4000 rad and 55% in the groups treated with 5000 and 6000 rad. For patients who achieved complete regression of the tumor following irradiation, the two-year survival rate is 40%, in contrast to 20% for those with partial regression, and no survivors among the patients with stable or progressive disease. The incidence of intrathoracic recurrence was 33% for patients treated with 6000 rad, 39% for those receiving 5000 rad, and 44 to 49% for those treated with a 4000-rad split or continuous course. At present, the data stongly suggest that patients treated with 5000 or 6000 rad have a better response, tumor control, and survival rate than those receiving lower doses. Patients with high performance status or with tumors in earlier stages have a two-year survival rate of approx. 40%, in comparison with 20% for other patients. The various irradiation regimens have been well tolerated, with complications being slightly higher in the 4000-rad split course group and in the 6000-rad continuous course group. The most frequent complications have been pneumonitis, pulmonary fibrosis, and dyspagia due to transient esophagitis. Further investigation will be necessary before the optimal management of patients with bronchogenic carcinoma by irradiation is established.

  2. Heterogeneous Combustion Particles with Distinctive Light-Absorbing and Light-Scattering Phases as Mimics of Internally-Mixed Ambient Atmospheric Particles

    NASA Astrophysics Data System (ADS)

    Conny, J. M.; Ma, X.; Gunn, L. R.

    2011-12-01

    Particles with heterogeneously-distributed light-absorbing and light-scattering phases were generated from incomplete combustion or thermal decomposition to mimic real atmospheric particles with distinctive optical properties. Individual particles and particle populations were characterized microscopically. The purpose was to examine how optical property measurements of internally-mixed ambient air particles might vary based on the properties of laboratory-generated particles produced under controlled conditions. The project is an initial stage in producing reference samples for calibrating instrumentation for monitoring climatically-important atmospheric aerosols. Binary-phase particles containing black carbon (BC) and a metal or a metal oxide phase were generated from the thermal decomposition or partial combustion of liquid fuels at a variety of temperatures from 600 °C to 1100 °C. Fuels included mixtures of toluene or isooctane and iron pentacarbonyl or titanium tetrachloride. Scanning electron microscopy with energy-dispersive x-ray spectroscopy revealed that burning the fuels at different temperatures resulted in distinctive differences in morphology and carbon vs. metal/metal oxide composition. Particles from toluene/Fe(CO)5 thermal decomposition exhibited aggregated morphologies that were classified as dendritic, soot-like, globular, or composited (dendritic-globular). Particles from isooctane/TiCl4 combustion were typically spherical with surface adducts or aggregates. Diameters of the BC/TiO2 particles averaged 0.68 μm to 0.70 μm. Regardless of combustion temperature, the most abundant particles in each BC/TiO2 sample had an aspect ratio of 1.2. However, for the 600 °C and 900 °C samples the distribution of aspect ratios was skewed toward much larger ratios suggesting significant chainlike aggregation. Carbon and titanium compositions (wt.) for the 600 °C sample were 12 % and 53 %, respectively. In contrast, the composition trended in the opposite

  3. Geant4 Monte Carlo simulation of absorbed dose and radiolysis yields enhancement from a gold nanoparticle under MeV proton irradiation

    NASA Astrophysics Data System (ADS)

    Tran, H. N.; Karamitros, M.; Ivanchenko, V. N.; Guatelli, S.; McKinnon, S.; Murakami, K.; Sasaki, T.; Okada, S.; Bordage, M. C.; Francis, Z.; El Bitar, Z.; Bernal, M. A.; Shin, J. I.; Lee, S. B.; Barberet, Ph.; Tran, T. T.; Brown, J. M. C.; Nhan Hao, T. V.; Incerti, S.

    2016-04-01

    Gold nanoparticles have been reported as a possible radio-sensitizer agent in radiation therapy due to their ability to increase energy deposition and subsequent direct damage to cells and DNA within their local vicinity. Moreover, this increase in energy deposition also results in an increase of the radiochemical yields. In this work we present, for the first time, an in silico investigation, based on the general purpose Monte Carlo simulation toolkit Geant4, into energy deposition and radical species production around a spherical gold nanoparticle 50 nm in diameter via proton irradiation. Simulations were preformed for incident proton energies ranging from 2 to 170 MeV, which are of interest for clinical proton therapy.

  4. Marrow transplantation for acute nonlymphoblastic leukemia in first remission: toxicity and long-term follow-up of patients conditioned with single dose or fractionated total body irradiation.

    PubMed

    Deeg, H J; Sullivan, K M; Buckner, C D; Storb, R; Appelbaum, F R; Clift, R A; Doney, K; Sanders, J E; Witherspoon, R P; Thomas, E D

    1986-12-01

    Seventy-five patients with acute nonlymphoblastic leukemia (ANL) in first remission were treated with cyclophosphamide, 60 mg/kg on each of two consecutive days followed by total body irradiation (TBI) at an exposure rate of 4-6 cGy/min from two opposing 60Co sources. The first 22 patients were given 9.2 Gy of TBI as a single dose. Subsequently 53 patients were randomized to receive either 10 Gy single dose TBI (n = 27) or 6 x 2 Gy fractionated TBI (n = 26). All patients received marrow transplants from HLA-identical siblings and all had sustained engraftment. Patients given 10 Gy of TBI had more early toxicity, especially veno-occlusive disease of the liver, than patients given 9.2 or 6 x 2 Gy of TBI. Idiopathic interstitial pneumonitis appeared to be more frequent in patients given 9.2 or 10 Gy single-dose TBI than in patients given 6 x 2 Gy fractionated TBI. Patients have now been followed from 5 to 9 years. Survival (+/- 95% confidence limits) at 5 years is 54 +/- 31% among patients given 9.2 Gy single dose TBI, 33 +/- 31% among patients given 10 Gy single dose TBI, and 54 +/- 26% among patients given 6 x 2 Gy fractionated TBI (P = 0.04). These results indicate that about half the patients with ANL transplanted while in first chemotherapy-induced remission can be expected to become long-term survivors.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3332129

  5. HemoHIM ameliorates the persistent down-regulation of Th1-like immune responses in fractionated γ-irradiated mice by modulating the IL-12p70-STAT4 signaling pathway.

    PubMed

    Park, Hae-Ran; Jo, Sung-Kee; Choi, Nam-Hee; Jung, Uhee

    2012-05-01

    Whole body irradiated mice appear to experience a down-regulation of the helper T (Th)1-like immune response, and maintain a persistent immunological imbalance. In the current study, we evaluated the effect of HemoHIM (an herbal product made from Angelica Radix, Cnidium officinale , and Paeonia japonica cultivated in Korea) to ameliorate the immunological imbalance induce in fractionated γ-irradiated mice. The mice were exposed to γ rays twice a week (0.5 Gy fractions) for a total dose of 5 Gy, and HemoHIM was administrated orally from 1 week before the first irradiation to 1 week before the final analysis. All experiments were performed 4 and 6 months after their first exposure. HemoHIM ameliorated the Th1- and Th2-related immune responses normally occur in irradiated mice with or without dinitrophenylated keyhole limpet hemocyanin immunization. HemoHIM also restored the natural killer cell activities without changing the percentage of natural killer cells in irradiated mice. Furthermore, the administration of HemoHIM prevented the reduction in levels of interleukin-12p70 in irradiated mice. Finally, we found that HemoHIM enhanced the phosphorylation of signal transducer and activator of transcription (STAT) 4 that was reduced in irradiated mice. Our findings suggest that HemoHIM ameliorates the persistent down-regulation of Th1-like immune responses by modulating the IL-12p70/pSTAT4 signaling pathway. PMID:22439601

  6. Paired organs--Should they be treated jointly or separately in internal dosimetry?

    SciTech Connect

    Parach, Ali-Asghar; Rajabi, Hossein; Askari, Mohammad-Ali

    2011-10-15

    Purpose: Size, shape, and the position of paired organs are different in abdomen. However, the counterpart organs are conventionally treated jointly together in internal dosimetry. This study was performed to quantify the difference of specific absorbed fraction of organs in considering paired organs jointly like single organs or as two separate organs. Methods: Zubal phantom and GATE Monte Carlo package were used to calculate the SAF for the self-absorption and cross-irradiation of the lungs, kidneys, adrenal glands (paired organs), liver, spleen, stomach, and pancreas (single organs). The activity was assumed uniformly distributed in the organs, and simulation was performed for monoenergetic photons of 10, 50, 100, 500, 1000 keV and mono-energetic electrons of 350, 500, 690, 935, 1200 keV. Results: The results demonstrated that self-absorption of left and right counterpart organs may be different depending upon the differences in their masses. The cross-irradiations between left-to-right and right-to-left counterpart organs are always equal irrespective of difference in their masses. Cross-irradiation from the left and right counterpart organs to other organs are different (4-24 times in Zubal phantom) depending on the photon energy and organs. The irradiation from a single source organ to the left and right counterpart paired organs is always different irrespective of activity concentration. Conclusions: Left and right counterpart organs always receive different absorbed doses from target organs and deliver different absorbed doses to target organs. Therefore, in application of radiopharmaceuticals in which the dose to the organs plays a role, counterpart organs should be treated separately as two separate organs.

  7. Protective Effect of the Ethyl Acetate Fraction of Sargassum muticum Against Ultraviolet B–Irradiated Damage in Human Keratinocytes

    PubMed Central

    Piao, Mei Jing; Yoon, Weon Jong; Kang, Hee Kyoung; Yoo, Eun Sook; Koh, Young Sang; Kim, Dong Sam; Lee, Nam Ho; Hyun, Jin Won

    2011-01-01

    The aim of this study was to investigate the cytoprotective properties of the ethyl acetate fraction of Sargassum muticum (SME) against ultraviolet B (UVB)-induced cell damage in human keratinocytes (HaCaT cells). SME exhibited scavenging activity toward the 1,1-diphenyl-2-picrylhydrazyl radicals and hydrogen peroxide (H2O2) and UVB-induced intracellular reactive oxygen species (ROS). SME also scavenged the hydroxyl radicals generated by the Fenton reaction (FeSO4 + H2O2), which was detected using electron spin resonance spectrometry. In addition, SME decreased the level of lipid peroxidation that was increased by UVB radiation, and restored the level of protein expression and the activities of antioxidant enzymes that were decreased by UVB radiation. Furthermore, SME reduced UVB-induced apoptosis as shown by decreased DNA fragmentation and numbers of apoptotic bodies. These results suggest that SME protects human keratinocytes against UVB-induced oxidative stress by enhancing antioxidant activity in cells, thereby inhibiting apoptosis. PMID:22174656

  8. Comparison of the immunosuppressive effect of fractionated total lymphoid irradiation (TLI) vs conventional immunosuppression (CI) in renal cadaveric allotransplantation

    SciTech Connect

    Waer, M.; Vanrenterghem, Y.; Ang, K.K.; van der Schueren, E.; Michielsen, P.; Vandeputte, M.

    1984-02-01

    Beginning in November 1981, eight patients with end stage diabetic nephropathy underwent renal cadaveric transplantation after TLI. Transplantation was done between 2 to 11 days after the end of a fractionated TLI to a total dose of 20 to 30 Gy. During the same observation period, 60 nondiabetic patients with end stage renal disease of different origin also received a cadaveric kidney graft, with a conventional regimen of immunosuppression that consists of anti-lymphocyte-globulin, tapering high doses of prednisone, and azathioprine. Phytohemagglutinin (PHA)-, concanavalin A (con A)-, and pokeweed mitogen (PWM)-induced blastogenesis, as well as the mixed lymphocyte reaction (MLR) and the cell-mediated lympholysis (CML) decreased progressively during the first months after conventional immunosuppression to 50% of the pretransplantation level, and remained there for the first year after transplantation. These tests were much more impaired after TLI and again no recovery occurred during the first year. In the clinic, the more profound immunosuppression in TLI patients was more frequently associated with viral infections (cytomegalovirus and herpes zoster). The incidence of rejections, however, was somewhat less frequent in the TLI-treated group and occurred significantly later. After TLI, the mean cumulative dose of steroids needed for kidney transplantation during the first year after transplantation could be substantially reduced.

  9. Absorbed dose assessment in newborns during x-ray examinations

    NASA Astrophysics Data System (ADS)

    Taipe, Patricia K.; Berrocal, Mariella J.; Carita, Raúl F.

    2012-02-01

    Often a newborn presents breathing problems during the early days of life, i.e. bronchopneumonia, wich are caused in most of cases, by aspirating a mixture of meconium and amniotic fluid. In these cases, it is necessary to make use of a radiograph, requested by the physician to reach a diagnosis. This paper seeks to evaluate the absorbed doses in neonates undergoing a radiograph. For this reason we try to simulate the real conditions in a X-ray room from Lima hospitals. With this finality we perform a simulation made according a questionnaire related to technical data of X-ray equipment, distance between the source and the neonate, and its position to be irradiated. The information obtained has been used to determine the absorbed dose by infants, using the MCNP code. Finally, the results are compared with reference values of international health agencies.

  10. Synthesis of Strong Light Scattering Absorber of TiO₂-CMK-3/Ag for Photocatalytic Water Splitting under Visible Light Irradiation.

    PubMed

    Hung, Wei Hsuan; Lai, Sz Nian; Lo, An Ya

    2015-04-29

    The enhanced water splitting photocurrent has been observed through plasmonic mesoporous composite electrode TiO2-CMK-3/Ag under visible light irradiation. Strong light absorption achieved from the integrations of ordered mesoporous carbon (CMK-3) and silver plasmonic nanoparticles (NPs) layer in the TiO2, which significantly increased the effective optical depth of TiO2-CMK-3/Ag photoelectrode. The carbon-based CMK-3 also increased the surface wetting behavior and conductivity of the photoelectrodes, which resulted in a higher ion exchange rate and faster electron transport. The synthesis of high crystalline TiO2-CMK-3/Ag composite photocatalyst was verified by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Pronounced enhancement of light absorption of TiO2-CMK-3/Ag photoelectrode was confirmed by UV/vis spectrophotometers. Two orders of magnitude of the enhanced water splitting photocurrent were obtained in the TiO2-CMK-3/Ag composite photoelectrode with respect to TiO2 only. Finally, spatially resolved mapping photocurrents were also demonstrated in this study. PMID:25848834

  11. Current Role of Selective Internal Irradiation With Yttrium-90 Microspheres in the Management of Hepatocellular Carcinoma: A Systematic Review

    SciTech Connect

    Lau, Wan Yee; Lai, Eric C.H.; Leung, Thomas W.T.

    2011-10-01

    Purpose: This article reviews the role of selective internal irradiation (SIR) with yttrium-90 ({sup 90}Y) microspheres for hepatocellular carcinoma (HCC). Methods and Materials: Studies were identified by searching Medline and PubMed databases for articles from 1990 to 2009 using the keywords 'selective internal irradiation,' 'hepatocellular carcinoma,' 'therapeutic embolization,' and 'yttrium-90.' Results: {sup 90}Y microspheres are a safe and well-tolerated therapy for unresectable HCC (median survival range, 7 -21.6 months). The evidence was limited to cohort studies and comparative studies with historical control. {sup 90}Y microspheres have been reported to downstage unresectable HCC to allow for salvage treatments with curative intent, act as a bridging therapy before liver transplantation, and treat HCC with curative intent for patients who are not surgical candidates because of comorbidities. Conclusions: {sup 90}Y microsphere is recommended as an option of palliative therapy for large or multifocal HCC without major portal vein invasion or extrahepatic spread. It can also be used for recurrent unresectable HCC, as a bridging therapy before liver transplantation, as a tumor downstaging treatment, and as a curative treatment for patients with associated comorbidities who are not candidates for surgery.

  12. Improvement of colour strength and colourfastness properties of gamma irradiated cotton using reactive black-5

    NASA Astrophysics Data System (ADS)

    Ahmad Bhatti, Ijaz; Adeel, Shahid; Nadeem, Raziya; Asghar, Toheed

    2012-03-01

    The dyeing behaviour of gamma irradiated cotton fabric using Reactive Black-5 dye powder has been investigated. The mercerized, bleached and plain weaved cotton fabric was irradiated to different absorbed doses of 100, 200, 300, 400, 500 and 600 Gy using Co-60 gamma irradiator. Dyeing was performed using irradiated and un-irradiated cotton with dye solutions. The dyeing parameters such as temperature of dyeing, time of dyeing and pH of dyeing solutions were optimised. The colour strength values of dyed fabrics were evaluated by comparing irradiated and un-irradiated cotton in CIE Lab system using Spectra flash SF650. Methods suggested by International Standard Organisation (ISO) were employed to study the effect of gamma irradiation on the colourfastness properties of dyed fabric. It is found that gamma irradiated cotton dyed with Reactive Black-5 has not only improved the colour strength but also enhanced the rating of fastness properties.

  13. [Long-term results and cause of failure analysis in larynx cancer patients irradiated conventionally and with accelerated fractionation schedules in 1995-1998].

    PubMed

    Szutkowski, Zbigniew; Kawecki, Andrzej; Jarząbski, Andrzej

    2014-01-01

    The clinical material consists of 217 patients with squamous cell carcinoma in supraglottic and glottic larynx in clinical stage T1-3N0M0 irradiated radically in Warsaw Oncology Centre in 1995-1998. All patients were treated with Co-60, according to two schedules of fractionation, with maintenance of the consistent therapeutic protocol. The same team of doctors worked on the treatment of patients and on the follow-up as well. The clinical material is a part of a three-phased clinical trial KBN 0295. In the course of observation, the progression of cancer was not observed in 157 patients, among whom, 66% were treated conventionally and 79% with accelerated fractionation method. 60 cases of loco-regional recurrences were noted, among which 55 were regional. The majority of failure cases was observed until the 30(th) of the month after the radiotherapy ended. In conventional fractionation treatment, recurrences in T1 were 8/31 (26%), in T2 22/59 (37%) and in T3 8/20 (40%). In patients treated with AF, recurrences were T1 5/39 (13%), T2 15/55 (27%) and T3 2/13 (15%) respectively. The percentage of primary site tumour recurrences for each localization and kind of treatment was analysed. In CF 28/78 (37%) of glottic tumour recurrences and 10/34 (29%) of supraglottic tumour, recurrences were observed. In AF, 12/71 (17%) and 10/36 (28%) were observed respectively. In 48 cases salvage surgery was used, and 12 patients were not qualified because of tumour massive progression or because they refused to have a surgery. Among 34 cases (16%) of the second primary tumour or distant methastases, 25 were observed with glottic cancer, among which 23 were observed in early stages, and 9 cases with supraglottic cancer, among which, 6 showed early stage of tumour. In only 3 cases out of all the patients, distant methastases were confirmed in histopatology examination. The main cause of failure in larynx cancer patients in stage T1 is that 3N0M0 are local recurrences. Second primary or

  14. Determination of neutron absorbed doses in lithium aluminates.

    PubMed

    Delfín Loya, A; Carrera, L M; Ureña-Núñez, F; Palacios, O; Bosch, P

    2003-04-01

    Lithium-based ceramics have been proposed as tritium breeders for fusion reactors. The lithium aluminate (gamma phase) seems to be thermally and structurally stable, the damages produced by neutron irradiation depend on the absorbed dose. A method based on the measurement of neutron activation of foils through neutron capture has been developed to obtain the neutron absorbed dose in lithium aluminates irradiated in the thermal column facility and in the fixed irradiation system of a Triga Mark III Nuclear Reactor. PMID:12672632

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

    PubMed

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

    2016-07-21

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  17. Production and in vivo imaging of (203)Pb as a surrogate isotope for in vivo (212)Pb internal absorbed dose studies.

    PubMed

    Máthé, Domokos; Szigeti, Krisztián; Hegedűs, Nikolett; Horváth, Ildikó; Veres, Dániel S; Kovács, Béla; Szűcs, Zoltán

    2016-08-01

    (212)Pb is a clinically relevant therapeutic alpha emitter isotope. A surrogate, (203)Pb, if prepared with sufficiently high specific activity could be used to estimate (212)Pb in vivo absorbed doses. An improved production procedure of (203)Pb with a simple, new separation method and high specific radioactivity for imaging is reported. We determined the in-vivo biodistribution of (203)Pb in mice by SPECT/CT. This highlights application possibilities of (203)Pb for further in vivo and clinical uses (radiolabeled (212)Pb-peptide co-injection, dosimetry calculation). PMID:27156049

  18. SOLSPEC investigation on board the International Space Station: The Absolute Solar Spectral Irradiance in the Infrared Domain

    NASA Astrophysics Data System (ADS)

    Thuillier, Gérard; Harder, Jerry; Shapiro, Alexander; Woods, Thomas; Perrin, Jean-Marie; Snow, Marty; Sukhodolov, Timofei; Schmutz, Werner

    2015-04-01

    Onboard the SOLAR payload of the International Space Station (ISS), the SOLSPEC spectrometer measures the solar spectral irradiance (SSI) from 16 to 2900 nm. This instrument uses lamps to monitor its behavior in orbit. In particular, it employs two tungsten ribbon lamps in the IR domain (1000-2900 nm). Initially, the infrared absolute irradiance scale was determined from the preflight laboratory calibration coefficients and the in-flight measurements gathered at first light in April 2008. Subsequent publications suggest a systematic discrepancy between SOLAR-ISS measurements and the ATLAS 3 spectrum obtained from SOLSPEC observations onboard the shuttle-ATLAS missions with the discrepancy reaching 10 % at 1800 nm. We show that such a discrepancy has strong implications for the Total Solar Irradiance (TSI) and the brightness temperature of the lower solar photosphere. Furthermore, comparisons with independent spectra either obtained on ground and in space will be also shown and commented. The origin of the ATLAS 3 to SOLSPEC differences have been extensively analyzed; the onboard lamp and solar data time series indicates that the IR spectrometer did not reach a permanent regime until after several months of operation. The solar measurements at first light and in permanent regime show a difference, which provides an effective wavelength dependent correction factor for the first light spectrum. The SOLSPEC-ISS spectrum obtained in this permanent regime is consistent with the ATLAS 3 spectrum within their combined uncertainties and will be identified in the literature as SOLAR 2rev. We present analysis of this SOLAR 2rev spectrum in terms of its contribution to TSI, the lower photospheric temperature, and comparisons with independently measured IR spectra from ground-based and on-orbit platforms.

  19. Solar EUV Irradiance Measurements by the Auto-Calibrating EUV Spectrometers (SolACES) Aboard the International Space Station (ISS)

    NASA Astrophysics Data System (ADS)

    Schmidtke, G.; Nikutowski, B.; Jacobi, C.; Brunner, R.; Erhardt, C.; Knecht, S.; Scherle, J.; Schlagenhauf, J.

    2014-05-01

    SolACES is part of the ESA SOLAR ISS mission that started aboard the shuttle mission STS-122 on 7 February 2008. The instrument has recorded solar extreme ultraviolet (EUV) irradiance from 16 to 150 nm during the extended solar activity minimum and the beginning solar cycle 24 with rising solar activity and increasingly changing spectral composition. The SOLAR mission has been extended from a period of 18 months to > 8 years until the end of 2016. SolACES is operating three grazing incidence planar grating spectrometers and two three-current ionization chambers. The latter ones are considered as primary radiometric detector standards. Re-filling the ionization chambers with three different gases repeatedly and using overlapping band-pass filters, the absolute EUV fluxes are derived in these spectral intervals. This way the serious problem of continuing efficiency changes in space-borne instrumentation is overcome during the mission. Evaluating the three currents of the ionization chambers, the overlapping spectral ranges of the spectrometers and of the filters plus inter-comparing the results from the EUV photon absorption in the gases with different absorption cross sections, there are manifold instrumental possibilities to cross-check the results providing a high degree of reliability to the spectral irradiance derived. During the mission a very strong up-and-down variability of the spectrometric efficiency by orders of magnitude is observed. One of the effects involved is channeltron degradation. However, there are still open questions on other effects contributing to these changes. A survey of the measurements carried out and first results of the solar spectral irradiance (SSI) data are presented. Inter-comparison with EUV data from other space missions shows good agreement such that the international effort has started to elaborate a complete set of EUV-SSI data taking into account all data available from 2008 to 2013.

  20. Measurement of ion species in high current ECR H+/D+ ion source for IFMIF (International Fusion Materials Irradiation Facility)

    NASA Astrophysics Data System (ADS)

    Shinto, K.; Senée, F.; Ayala, J.-M.; Bolzon, B.; Chauvin, N.; Gobin, R.; Ichimiya, R.; Ihara, A.; Ikeda, Y.; Kasugai, A.; Kitano, T.; Kondo, K.; Marqueta, A.; Okumura, Y.; Takahashi, H.; Valette, M.

    2016-02-01

    Ion species ratio of high current positive hydrogen/deuterium ion beams extracted from an electron-cyclotron-resonance ion source for International Fusion Materials Irradiation Facility accelerator was measured by the Doppler shift Balmer-α line spectroscopy. The proton (H+) ratio at the middle of the low energy beam transport reached 80% at the hydrogen ion beam extraction of 100 keV/160 mA and the deuteron (D+) ratio reached 75% at the deuterium ion beam extraction of 100 keV/113 mA. It is found that the H+ ratio measured by the spectroscopy gives lower than that derived from the phase-space diagram measured by an Allison scanner type emittance monitor. The H+/D+ ratio estimated by the emittance monitor was more than 90% at those extraction currents.

  1. External Beam Accelerated Partial-Breast Irradiation Using 32 Gy in 8 Twice-Daily Fractions: 5-Year Results of a Prospective Study

    SciTech Connect

    Pashtan, Itai M.; Recht, Abram; Ancukiewicz, Marek; Brachtel, Elena; Abi-Raad, Rita F.; D'Alessandro, Helen A.; Levy, Antonin; Wo, Jennifer Y.; Hirsch, Ariel E.; Kachnic, Lisa A.; Goldberg, Saveli; Specht, Michelle; Gadd, Michelle; Smith, Barbara L.; Powell, Simon N.; Taghian, Alphonse G.

    2012-11-01

    Purpose: External beam accelerated partial breast irradiation (APBI) is an increasingly popular technique for treatment of patients with early stage breast cancer following breast-conserving surgery. Here we present 5-year results of a prospective trial. Methods and Materials: From October 2003 through November 2005, 98 evaluable patients with stage I breast cancer were enrolled in the first dose step (32 Gy delivered in 8 twice-daily fractions) of a prospective, multi-institutional, dose escalation clinical trial of 3-dimensional conformal external beam APBI (3D-APBI). Median age was 61 years; median tumor size was 0.8 cm; 89% of tumors were estrogen receptor positive; 10% had a triple-negative phenotype; and 1% had a HER-2-positive subtype. Median follow-up was 71 months (range, 2-88 months; interquartile range, 64-75 months). Results: Five patients developed ipsilateral breast tumor recurrence (IBTR), for a 5-year actuarial IBTR rate of 5% (95% confidence interval [CI], 1%-10%). Three of these cases occurred in patients with triple-negative disease and 2 in non-triple-negative patients, for 5-year actuarial IBTR rates of 33% (95% CI, 0%-57%) and 2% (95% CI, 0%-6%; P<.0001), respectively. On multivariable analysis, triple-negative phenotype was the only predictor of IBTR, with borderline statistical significance after adjusting for tumor grade (P=.0537). Conclusions: Overall outcomes were excellent, particularly for patients with estrogen receptor-positive disease. Patients in this study with triple-negative breast cancer had a significantly higher IBTR rate than patients with other receptor phenotypes when treated with 3D-APBI. Larger, prospective 3D-APBI clinical trials should continue to evaluate the effect of hormone receptor phenotype on IBTR rates.

  2. Academic difficulties and occupational outcomes of adult survivors of childhood leukemia who have undergone allogeneic hematopoietic stem cell transplantation and fractionated total body irradiation conditioning.

    PubMed

    Freycon, Fernand; Trombert-Paviot, Béatrice; Casagranda, Léonie; Frappaz, Didier; Mialou, Valérie; Armari-Alla, Corinne; Gomez, Frederic; Faure-Conter, Cécile; Plantaz, Dominique; Berger, Claire

    2014-04-01

    We studied academic and employment outcomes in 59 subjects who underwent allogeneic hematopoietic stem cell transplantation (a-HSCT) with fractionated total body irradiation (fTBI) for childhood leukemia, comparing them with, first, the general French population and, second, findings in 19 who underwent a-HSCT with chemotherapy conditioning. We observed an average academic delay of 0.98 years among the 59 subjects by Year 10 of secondary school (French class Troisième), which was higher than the 0.34-year delay in the normal population (P < .001) but not significantly higher than the delay of 0.68 years in our cohort of 19 subjects who underwent a-HSCT with chemotherapy. The delay was dependent on age at leukemia diagnosis, but not at fTBI. This delay increased to 1.32 years by the final year of secondary school (Year 13, Terminale) for our 59 subjects versus 0.51 years in the normal population (P = .0002), but did not differ significantly from the 1.08-year delay observed in our cohort of 19 subjects. The number of students who received their secondary school diploma (Baccalaureate) was similar to the expected rate in the general French population for girls (observed/expected = 1.02) but significantly decreased for boys (O/E = 0.48; CI: 95%[0.3-0.7]). Compared with 13.8% of the general population, 15.3% of the cancer survivors received no diploma (P = NS). Reported job distribution did not differ significantly between our cohort of childhood cancer survivors and the general population except that more female survivors were employed in intermediate-level professional positions. Academic difficulties after fTBI are common and their early identification will facilitate educational and professional achievement. PMID:24087985

  3. Development of mathematical pediatric phantoms for internal dose calculations: designs, limitations, and prospects

    SciTech Connect

    Cristy, M.

    1980-01-01

    Mathematical phantoms of the human body at various ages are employed with Monte Carlo radiation transport codes for calculation of photon specific absorbed fractions. The author has developed a pediatric phantom series based on the design of the adult phantom, but with explicit equations for each organ so that organ sizes and marrow distributions could be assigned properly. Since the phantoms comprise simple geometric shapes, predictive dose capability is limited when geometry is critical to the calculation. Hence, there is a demand for better phantom design in situations where geometry is critical, such as for external irradiation or for internal emitters with low energy photons. Recent advances in computerized axial tomography (CAT) present the potential for derivation of anatomical information, which is so critical to development of phantoms, and ongoing developmental work on compuer architecture to handle large arrays for Monte Carlo calculations should make complex-geometry dose calculations economically feasible within this decade.

  4. Mucool Hydrogen Absorber R and D

    SciTech Connect

    Cummings, Mary Anne

    2006-03-20

    The Mucool hydrogen absorber program will be presented. An update of current projects will be described, and the next year's plan will be reviewed, along with efforts in collaboration with the Muon International Cooling Experiment.

  5. Effect of mercerization and gamma irradiation on the dyeing behaviour of cotton using stilbene based direct dye

    NASA Astrophysics Data System (ADS)

    Bhatti, Ijaz Ahmad; Adeel, Shahid; Fazal-ur-Rehman; Irshad, Misbah; Abbas, Muhammad

    2012-07-01

    The dyeing behaviour of mercerized and gamma irradiated cotton fabric using stilbene based direct dye has been investigated. The fabric was treated with different concentrations of alkali to optimize the mercerization. The optimum mercerized cotton fabric was irradiated to absorbed doses of 2, 4, 6, 8 and 10 kGy using Cs-137 gamma irradiator. Dyeing was performed using irradiated and un-irradiated cotton with dye solutions. The dyeing parameters such as temperature, time of dyeing, pH of dyeing solutions and salt concentration were optimized. The colour strength values of dyed fabrics were evaluated by comparing irradiated and un-irradiated cotton in CIE Lab system using Spectra flash SF650. Methods suggested by International Standard Organization (ISO) were employed to study the effect of gamma irradiation on the colourfastness properties of dyed fabric. It was found that mercerized and irradiated cotton have not only improved the colour strength but enhanced the rating of fastness properties also.

  6. Escherichia coli O157:H7 biofilm formation and internalization on lettuce and spinach leaf surfaces reduces efficacy of irradiation and sodium hypochlorite washes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Escherichia coli O157:H7 contamination of leafy green vegetables is an ongoing concern for consumers. Biofilm-associated and internalized pathogens are relatively resistant to chemical treatments, but little is known about the response of these protected pathogens to irradiation. Leaves of Romaine l...

  7. Optimization of the fractionated irradiation scheme considering physical doses to tumor and organ at risk based on dose–volume histograms

    SciTech Connect

    Sugano, Yasutaka; Mizuta, Masahiro; Takao, Seishin; Shirato, Hiroki; Sutherland, Kenneth L.; Date, Hiroyuki

    2015-11-15

    Purpose: Radiotherapy of solid tumors has been performed with various fractionation regimens such as multi- and hypofractionations. However, the ability to optimize the fractionation regimen considering the physical dose distribution remains insufficient. This study aims to optimize the fractionation regimen, in which the authors propose a graphical method for selecting the optimal number of fractions (n) and dose per fraction (d) based on dose–volume histograms for tumor and normal tissues of organs around the tumor. Methods: Modified linear-quadratic models were employed to estimate the radiation effects on the tumor and an organ at risk (OAR), where the repopulation of the tumor cells and the linearity of the dose-response curve in the high dose range of the surviving fraction were considered. The minimization problem for the damage effect on the OAR was solved under the constraint that the radiation effect on the tumor is fixed by a graphical method. Here, the damage effect on the OAR was estimated based on the dose–volume histogram. Results: It was found that the optimization of fractionation scheme incorporating the dose–volume histogram is possible by employing appropriate cell surviving models. The graphical method considering the repopulation of tumor cells and a rectilinear response in the high dose range enables them to derive the optimal number of fractions and dose per fraction. For example, in the treatment of prostate cancer, the optimal fractionation was suggested to lie in the range of 8–32 fractions with a daily dose of 2.2–6.3 Gy. Conclusions: It is possible to optimize the number of fractions and dose per fraction based on the physical dose distribution (i.e., dose–volume histogram) by the graphical method considering the effects on tumor and OARs around the tumor. This method may stipulate a new guideline to optimize the fractionation regimen for physics-guided fractionation.

  8. Influence of the fractioned irradiation energy in the phototherapy with low intensity laser on the growth of human dental pulp fibroblasts

    NASA Astrophysics Data System (ADS)

    Meneguzzo, D. T.; Eduardo, C. P.; Ribeiro, M. S.; Marques, M. M.

    2008-03-01

    Laser phototherapy has proven to improve treatment of several pathologies in dentistry. The aim of the present study was to analyze the low power laser phototherapy effects comparing multiple irradiations with the same total energy at once. This in vitro study focuses on the biostimulation of cellular growth of pulp fibroblasts (FP5 cell lineage). The cells were grown in Dulbecco's Modified Eagle's (DME) medium with either 5% (nutritional deficit) or 10% fetal bovine serum (FBS). Laser irradiation was carried out with diode lasers with the following parameters: 685 nm, 40 mW, spot size 0.019 cm2. The groups were: G1(6.3J/cm2, 3 s, 0.12J), G2 (12.6J/cm2, 6 s, 0.24J), G3 (18.9J/cm2, 9 s, 0.36J), G4 (2 irradiations of 6.3J/cm2, 0.24J), G5 (3 irradiations of 6.3J/cm2, 0.36J), G6 (5% SFB, negative control, without irradiation), and G7 (10% SFB, positive control, without irradiation). On groups G4 and G5 the irradiation was performed with 6h-intervals. For growth analysis, the MTT test was used 24 hours after the last irradiation. The data from spectrophotometer were analyzed by ANOVA followed by the Tukey's test. The groups submitted to multiple irradiations presented significantly higher cell growth than the groups with single irradiation. This cell growth was similar to that of positive control group. The laser phototherapy with multiple irradiations is more effective on cellular growth.

  9. PILOT STUDY: An international comparison of mass fraction purity assignment of theophylline: CCQM Pilot Study CCQM-P20.e (Theophylline)

    NASA Astrophysics Data System (ADS)

    Westwood, S.; Josephs, R.; Daireaux, A.; Wielgosz, R.; Davies, S.; Kang, M.; Ting, H.; Phillip, R.; Malz, F.; Shimizu, Y.; Frias, E.; Pérez, M.; Apps, P.; Fernandes-Whaley, M.; DeVos, B.; Wiangnon, K.; Ruangrittinon, N.; Wood, S.; Duewer, D.; Schantz, M.; Bedner, M.; Hancock, D.; Esker, J.

    2009-01-01

    Under the auspices of the Organic Analysis Working Group (OAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) a laboratory comparison, CCQM-P20.e, was coordinated by the Bureau International de Poids et Mesures (BIPM) in 2006/2007. Nine national measurement institutes, two expert laboratories and the BIPM participated in the comparison. Participants were required to assign the mass fraction of theophylline present as the main component in two separate study samples (CCQM-P20.e.1 and CCQM-P20.e.2). CCQM-P20.e.1 consisted of a high-purity theophylline material obtained from a commercial supplier. CCQM-P20.e.2 consisted of theophylline to which known amounts of the related structure compounds theobromine and caffeine were added in a homogenous, gravimetrically controlled fashion. For the CCQM-P20.e.2 sample it was possible to estimate gravimetric reference values both for the main component and for the two spiked impurities. In addition to assigning the mass fraction content of theophylline for both materials, participants were requested but not obliged to provide mass fraction estimates for the minor components they identified in each sample. The results reported by the study participants for the mass fraction content of theophylline in both materials showed good levels of agreement both with each other and with the gravimetric reference value assigned to the CCQM-P20.e.2 material. There was also satisfactory agreement overall, albeit at higher levels of uncertainty, in the quantification data reported for the minor components present in both samples. In the few cases where a significant deviation was observed from the consensus values reported by the comparison participants or gravimetric reference values where these where available, they appeared to arise from the use of non-optimal chromatographic separation conditions. The results demonstrate the feasibility for laboratories to assign mass fraction content with associated absolute expanded

  10. 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.

  11. Operation and commissioning of IFMIF (International Fusion Materials Irradiation Facility) LIPAc injector.

    PubMed

    Okumura, Y; Gobin, R; Knaster, J; Heidinger, R; Ayala, J-M; Bolzon, B; Cara, P; Chauvin, N; Chel, S; Gex, D; Harrault, F; Ichimiya, R; Ihara, A; Ikeda, Y; Kasugai, A; Kikuchi, T; Kitano, T; Komata, M; Kondo, K; Maebara, S; Marqueta, A; O'Hira, S; Perez, M; Phillips, G; Pruneri, G; Sakamoto, K; Scantamburlo, F; Senée, F; Shinto, K; Sugimoto, M; Takahashi, H; Usami, H; Valette, M

    2016-02-01

    The objective of linear IFMIF prototype accelerator is to demonstrate 125 mA/CW deuterium ion beam acceleration up to 9 MeV. The injector has been developed in CEA Saclay and already demonstrated 140 mA/100 keV deuterium beam [R. Gobin et al., Rev. Sci. Instrum. 85, 02A918 (2014)]. The injector was disassembled and delivered to the International Fusion Energy Research Center in Rokkasho, Japan. After reassembling the injector, commissioning has started in 2014. Up to now, 100 keV/120 mA/CW hydrogen and 100 keV/90 mA/CW deuterium ion beams have been produced stably from a 10 mm diameter extraction aperture with a low beam emittance of 0.21 π mm mrad (rms, normalized). Neutron production by D-D reaction up to 2.4 × 10(9) n/s has been observed in the deuterium operation. PMID:26931957

  12. Composition for absorbing hydrogen

    DOEpatents

    Heung, L.K.; Wicks, G.G.; Enz, G.L.

    1995-05-02

    A hydrogen absorbing composition is described. The composition comprises a porous glass matrix, made by a sol-gel process, having a hydrogen-absorbing material dispersed throughout the matrix. A sol, made from tetraethyl orthosilicate, is mixed with a hydrogen-absorbing material and solidified to form a porous glass matrix with the hydrogen-absorbing material dispersed uniformly throughout the matrix. The glass matrix has pores large enough to allow gases having hydrogen to pass through the matrix, yet small enough to hold the particles dispersed within the matrix so that the hydrogen-absorbing particles are not released during repeated hydrogen absorption/desorption cycles.

  13. Composition for absorbing hydrogen

    DOEpatents

    Heung, Leung K.; Wicks, George G.; Enz, Glenn L.

    1995-01-01

    A hydrogen absorbing composition. The composition comprises a porous glass matrix, made by a sol-gel process, having a hydrogen-absorbing material dispersed throughout the matrix. A sol, made from tetraethyl orthosilicate, is mixed with a hydrogen-absorbing material and solidified to form a porous glass matrix with the hydrogen-absorbing material dispersed uniformly throughout the matrix. The glass matrix has pores large enough to allow gases having hydrogen to pass through the matrix, yet small enough to hold the particles dispersed within the matrix so that the hydrogen-absorbing particles are not released during repeated hydrogen absorption/desorption cycles.

  14. Use of the Normalized Absorbance Ratio as an Internal Standardization Approach To Minimize Measurement Error in Enzyme-Linked Immunosorbent Assays for Diagnosis of Human Papillomavirus Infection▿

    PubMed Central

    Ramanakumar, Agnihotram V.; Thomann, Patricia; Candeias, Joao M.; Ferreira, Silvaneide; Villa, Luisa L.; Franco, Eduardo L.

    2010-01-01

    The serological detection of antibodies against human papillomavirus (HPV) antigens is a useful tool to determine exposure to genital HPV infection and in predicting the risk of infection persistence and associated lesions. Enzyme-linked immunosorbent assays (ELISAs) are commonly used for seroepidemiological studies of HPV infection but are not standardized. Intra- and interassay performance variation is difficult to control, especially in cohort studies that require the testing of specimens over extended periods. We propose the use of normalized absorbance ratios (NARs) as a standardization procedure to control for such variations and minimize measurement error. We compared NAR and ELISA optical density (OD) values for the strength of the correlation between serological results for paired visits 4 months apart and HPV-16 DNA positivity in cervical specimens from a cohort investigation of 2,048 women tested with an ELISA using HPV-16 virus-like particles. NARs were calculated by dividing the mean blank-subtracted (net) ODs by the equivalent values of a control serum pool included in the same plate in triplicate, using different dilutions. Stronger correlations were observed with NAR values than with net ODs at every dilution, with an overall reduction in nonexplained regression variability of 39%. Using logistic regression, the ranges of odds ratios of HPV-16 DNA positivity contrasting upper and lower quintiles at different dilutions and their averages were 4.73 to 5.47 for NARs and 2.78 to 3.28 for net ODs, with corresponding significant improvements in seroreactivity-risk trends across quintiles when NARs were used. The NAR standardization is a simple procedure to reduce measurement error in seroepidemiological studies of HPV infection. PMID:20053861

  15. Internal Mammary Lymph Node Irradiation Contributes to Heart Dose in Breast Cancer

    SciTech Connect

    Chargari, Cyrus; Castadot, Pierre; MacDermed, Dhara; Vandekerkhove, Christophe; Bourgois, Nicolas; Van Houtte, Paul; Magne, Nicolas

    2010-10-01

    We assessed the impact of internal mammary chain radiotherapy (IMC RT) to the radiation dose received by the heart in terms of heart dose-volume histogram (DVH). Thirty-six consecutive breast cancer patients presenting with indications for IMC RT were enrolled in a prospective study. The IMC was treated by a standard conformal RT technique (50 Gy). For each patient, a cardiac DVH was generated by taking into account the sole contribution of IMC RT. Cardiac HDV were compared according to breast cancer laterality and the type of previous surgical procedure, simple mastectomy or breast conservative therapy (BCT). The contribution of IMC RT to the heart dose was significantly greater for patients with left-sided versus right-sided tumors (13.8% and 12.8% for left-sided tumors versus 3.9% and 4.2% for right-sided tumors in the BCT group and the mastectomy group, respectively; p < 0.0001). There was no statistically significant difference in IMC contribution depending on the initial surgical procedure. IMC RT contributes to cardiac dose for both left-sided and right-sided breast cancers, although the relative contribution is greater in patients with left-sided tumors.

  16. Research in radiobiology: Annual report of work in progress in the internal irradiation program

    SciTech Connect

    Miller, S.C.; Buster, D.S.

    1987-12-31

    In the early 1950's the Atomic Energy Commission established at the University of Utah a large, long-term study designed to investigate the toxicity of internally deposited radionuclides in beagles. The first animals were injected on December 1, 1952 and thus began an odyssey unusual in modern science both for its duration and continued scientific interest and relevance. The original dogs were injected with /sup 239/Pu and /sup 226/Ra. Later, studies were initiated with /sup 241/Am, /sup 249/Cf, /sup 252/Cf, /sup 253/Es, /sup 224/Ra, /sup 228/Ra, /sup 90/Sr, and /sup 228/Th. These studies were unique and have and will continue to contribute valuable scientific information on the behavior and effects of these substances in biological systems. We feel that the data collected from these studies will be useful for many decades to come as we ask more demanding questions relative to radionuclides and environmental, biological and health issues. While this publication will be the last of our series Research in Radiobiology, the lifespan carcinogenesis studies are continuing under a collaborative arrangement with the I.T.R.I. Beginning in 1988, the colony status tables of dogs in the Utah studies and reports of research by the Radiobiology faculty will be included in the annual I.T.R.I. report. Under our new collaborative arrangements with the I.T.R.I. for the conduct of the lifespan carcinogenesis studies, we expect a continued high level of scientific productivity from our faculty.

  17. Radiation-Free Weekend Rescued! Continuous Accelerated Irradiation of 7-Days per Week Is Equal to Accelerated Fractionation With Concomitant Boost of 7 Fractions in 5-Days per Week: Report on Phase 3 Clinical Trial in Head-and-Neck Cancer Patients

    SciTech Connect

    Skladowski, Krzysztof; Hutnik, Marcin; Wygoda, Andrzej; Golen, Maria; Pilecki, Boleslaw; Przeorek, Wieslawa; Rutkowski, Tomasz; Lukaszczyk-Widel, Beata; Heyda, Alicja; Suwinski, Rafal; Tarnawski, Rafal; Maciejewski, Boguslaw

    2013-03-01

    Purpose: To report long-term results of randomized trial comparing 2 accelerated fractionations of definitive radiation therapy assessing the need to irradiate during weekend in patients with head and neck squamous cell carcinoma. Methods and Materials: A total of 345 patients with SCC of the oral cavity, larynx, and oro- or hypo-pharynx, stage T2-4N0-1M0, were randomized to receive continuous accelerated irradiation (CAIR: once per day, 7 days per week) or concomitant accelerated boost (CB: once per day, 3 days per week, and twice per day, 2 days per week). Total dose ranged from 66.6-72 Gy, dose per fraction was 1.8 Gy, number of fractions ranged from 37-40 fractions, and overall treatment time ranged from 37-40 days. Results: No differences for all trial end-points were noted. At 5 and 10 years, the actuarial rates of local-regional control were 63% and 60% for CAIR vs 65% and 60% for CB, and the corresponding overall survival were 40% and 25% vs 44% and 25%, respectively. Confluent mucositis was the main acute toxicity, with an incidence of 89% in CAIR and 86% in CB patients. The 5-year rate of grade 3-4 late radiation morbidity was 6% for both regimens. Conclusions: Results of this trial indicate that the effects of accelerated fractionation can be achieve by delivering twice-per-day irradiation on weekday(s). This trial has also confirmed that an accelerated, 6-weeks schedule is a reasonable option for patients with intermediate-stage head-and-neck squamous cell carcinoma because of the associated high cure rate and minimal severe late toxicity.

  18. Optimization of the Internal Magnetic Configuration for High Bootstrap Current Fraction and High Beta for Steady-state

    NASA Astrophysics Data System (ADS)

    Ferron, J. E.; Luce, T. C.; Politzer, P. A.; Deboo, J. C.; Petrie, T. W.; Petty, C. C.; La Haye, R. J.; Holcomb, C. T.; White, A. E.; Turco, F.; Doyle, E. J.; Rhodes, T. L.; Zeng, L.

    2009-11-01

    A systematic scan of the safety factor (q) profile has been used to study the optimum for steady-state operation, which requires the maximum possible beta and bootstrap current fraction (fBS) and good alignment between the total current density and the bootstrap current density (JBS). The ne, Te, and Ti profiles at constant βN= 2.7 were measured in a scan of the minimum q (1.12, and 3.8 at qmin= 1.1. These opposite trends in βN and fBS, and the improved current profile alignment for qmin<2, point to intermediate qmin and q95 as optimal for steady-state operation.

  19. Comparative assessment of single-dose and fractionated boron neutron capture therapy

    SciTech Connect

    Coderre, J.A.; Micca, P.L.; Fisher, C.D.

    1995-12-01

    The effects of fractionating boron neutron capture therapy (BNCT) were evaluated in the intracerebral rat 9L gliosarcoma and rat spinal cord models using the Brookhaven Medical Research Reactor (BMRR) thermal neutron beam. The amino acid analog p-boronophenylalanine (BPA) was administered prior to each exposure to the thermal neutron beam. The total physical absorbed dose to the tumor during BNCT using BPA was 91% high-linear energy transfer (LET) radiation. Two tumor doses of 5.2 Gy spaced 48 h apart (n = 14) or three tumor doses of 5.2 Gy, each separated by 48 h (n = 10), produced 50 and 60% long-term (>1 year) survivors, respectively. The outcome of neither the two nor the three fractions of radiation was statistically different from that of the corresponding single-fraction group. In the rat spinal cord, the ED{sub 50} for radiation myelopathy (as indicated by limb paralysis within 7 months) after exposure to the thermal beam alone was 13.6 {+-} 0.4 Gy. Dividing the beam-only irradiation into two or four consecutive daily fractions increased the ED{sub 50} to 14.7 {+-} 0.2 Gy and 15.5 {+-} 0.4 Gy, respectively. Thermal neutron irradiation in the presence of BPA resulted in an ED{sub 50} for myelopathy of 13.8 {+-} 0.6 Gy after a single fraction and 14.9 {+-} 0.9 Gy after two fractions. An increase in the number of fractions to four resulted in an ED{sub 50} of 14.3 {+-} 0.6 Gy. The total physical absorbed dose to the blood in the vasculature of the spinal cord during BNCT using BPA was 80% high-LET radiation. It was observed that fractionation was of minor significance in the amelioration of damage to the normal central nervous system in the rat after boron neutron capture irradiation. 30 refs., 5 figs., 3 tabs.

  20. Measuring absorbed dose for i-CAT CBCT examinations in child, adolescent and adult phantoms

    PubMed Central

    Choi, E

    2015-01-01

    Objectives: Design and construct child and adolescent head phantoms to measure the absorbed doses imparted during dental CBCT and compare with the absorbed dose measured in an adult phantom. Methods: A child phantom was developed to represent the smallest patients receiving CBCT, usually for craniofacial developmental concerns, and an adolescent phantom was developed to represent healthy orthodontic patients. Absorbed doses were measured using a thimble ionization chamber for the custom-built child and adolescent phantoms and compared with measurements using a commercially available adult phantom. Imaging was performed with an i-CAT Next Generation (Imaging Sciences International, Hatfield, PA) CBCT using two different fields of view covering the craniofacial complex (130 mm high) or maxilla/mandible (60 mm high). Results: Measured absorbed doses varied depending on the location of the ionization chamber within the phantoms. For CBCT images obtained using the same protocol for all phantoms, the highest absorbed dose was measured in all locations of the small child phantom. The lowest absorbed dose was measured in the adult phantom. Conclusions: Images were obtained with the same protocol for the adult, adolescent and child phantoms. A consistent trend was observed with the highest absorbed dose being measured in the smallest phantom (child), while the lowest absorbed dose was measured in the largest phantom (adult). This study demonstrates the importance of child-sizing the dose by using dedicated paediatric protocols optimized for the imaging task, which is critical as children are more sensitive to harmful effects of radiation and have a longer life-span post-irradiation for radiation-induced symptoms to develop than do adults. PMID:25785822

  1. Modelling Absorbent Phenomena of Absorbent Structure

    NASA Astrophysics Data System (ADS)

    Sayeb, S.; Ladhari, N.; Ben Hassen, M.; Sakli, F.

    Absorption, retention and strike through time, as evaluating criteria of absorbent structures quality were studied. Determination of influent parameters on these criteria were realized by using the design method of experimental sets. In this study, the studied parameters are: Super absorbent polymer (SAP)/fluff ratio, compression and the porosity of the non woven used as a cover stock. Absorption capacity and retention are mostly influenced by SAP/fluff ratio. However, strike through time is affected by compression. Thus, a modelling of these characteristics in function of the important parameter was established.

  2. Methods for absorbing neutrons

    DOEpatents

    Guillen, Donna P.; Longhurst, Glen R.; Porter, Douglas L.; Parry, James R.

    2012-07-24

    A conduction cooled neutron absorber may include a metal matrix composite that comprises a metal having a thermal neutron cross-section of at least about 50 barns and a metal having a thermal conductivity of at least about 1 W/cmK. Apparatus for providing a neutron flux having a high fast-to-thermal neutron ratio may include a source of neutrons that produces fast neutrons and thermal neutrons. A neutron absorber positioned adjacent the neutron source absorbs at least some of the thermal neutrons so that a region adjacent the neutron absorber has a fast-to-thermal neutron ratio of at least about 15. A coolant in thermal contact with the neutron absorber removes heat from the neutron absorber.

  3. Externally tuned vibration absorber

    DOEpatents

    Vincent, Ronald J.

    1987-09-22

    A vibration absorber unit or units are mounted on the exterior housing of a hydraulic drive system of the type that is powered from a pressure wave generated, e.g., by a Stirling engine. The hydraulic drive system employs a piston which is hydraulically driven to oscillate in a direction perpendicular to the axis of the hydraulic drive system. The vibration absorbers each include a spring or other resilient member having one side affixed to the housing and another side to which an absorber mass is affixed. In a preferred embodiment, a pair of vibration absorbers is employed, each absorber being formed of a pair of leaf spring assemblies, between which the absorber mass is suspended.

  4. Long-term Survival Outcomes Following Internal Mammary Node Irradiation in Stage II-III Breast Cancer: Results of a Large Retrospective Study With 12-Year Follow-up

    SciTech Connect

    Chang, Jee Suk; Park, Won; Kim, Yong Bae; Lee, Ik Jae; Keum, Ki Chang; Lee, Chang Geol; Choi, Doo Ho; Suh, Chang-Ok; Huh, Seung Jae

    2013-08-01

    Purpose: To examine the effect of internal mammary node irradiation (IMNI) on disease-free survival (DFS) and overall survival (OS) in breast cancer patients treated with modified radical mastectomy and postoperative radiation therapy. Methods and Materials: Between 1994 and 2002, 396 patients with stage II-III breast cancer were treated with postmastectomy radiation therapy with (n=197) or without (n=199) IMNI. Patients who received neoadjuvant chemotherapy were excluded. IMNI was administered at the clinical discretion of the treating physician. Median RT dose was 50.4 Gy (range, 45.0-59.4 Gy) in 28 fractions, with inclusion of the supraclavicular fossa in 96% of patients. Adjuvant chemotherapy was administered to 99.7% of the patients and endocrine therapy to 53%. Results: The median follow-up was 149 months (range, 124-202). IMNI patients had more advanced nodal stage and non-high grade tumors than those without IMNI (P<.001). Otherwise, disease and treatment characteristics were well balanced. The 10-year DFS with and without IMNI was 65% and 57%, respectively (P=.05). Multivariate analysis demonstrated that IMNI was an independent, positive predictor of DFS (hazard ratio [HR], 0.70; P=.02). Benefits of IMNI in DFS were seen most apparently in N2 patients (HR, 0.44; 95% confidence interval [CI], 0.26-0.74) and inner/central tumors (HR, 0.55; 95% CI, 0.34-0.90). The 10-year OS with and without IMNI was 72% and 66%, respectively (P=.62). The 10-year DFS and OS were 61%, and 69%, respectively. Conclusions: Internal mammary node irradiation significantly improved DFS in postmastectomy breast cancer patients. Pending long-term results from randomized trials, treatment of internal mammary nodes should be considered in postmastectomy radiation therapy.

  5. Blood irradiation: Rationale and technique

    SciTech Connect

    Lewis, M.C. )

    1990-01-01

    Upon request by the local American Red Cross, the Savannah Regional Center for Cancer Care irradiates whole blood or blood components to prevent post-transfusion graft-versus-host reaction in patients who have severely depressed immune systems. The rationale for blood irradiation, the total absorbed dose, the type of patients who require irradiated blood, and the regulations that apply to irradiated blood are presented. A method of irradiating blood using a linear accelerator is described.

  6. Leaf absorbance and photosynthesis

    NASA Technical Reports Server (NTRS)

    Schurer, Kees

    1994-01-01

    The absorption spectrum of a leaf is often thought to contain some clues to the photosynthetic action spectrum of chlorophyll. Of course, absorption of photons is needed for photosynthesis, but the reverse, photosynthesis when there is absorption, is not necessarily true. As a check on the existence of absorption limits we measured spectra for a few different leaves. Two techniques for measuring absorption have been used, viz. the separate determination of the diffuse reflectance and the diffuse transmittance with the leaf at a port of an integrating sphere and the direct determination of the non-absorbed fraction with the leaf in the sphere. In a cross-check both methods yielded the same results for the absorption spectrum. The spectrum of a Fuchsia leaf, covering the short-wave region from 350 to 2500 nm, shows a high absorption in UV, blue and red, the well known dip in the green and a steep fall-off at 700 nm. Absorption drops to virtually zero in the near infrared, with subsequent absorptions, corresponding to the water absorption bands. In more detailed spectra, taken at 5 nm intervals with a 5 nm bandwidth, differences in chlorophyll content show in the different depths of the dip around 550 nm and in a small shift of the absorption edge at 700 nm. Spectra for Geranium (Pelargonium zonale) and Hibiscus (with a higher chlorophyll content) show that the upper limit for photosynthesis can not be much above 700 nm. No evidence, however, is to be seen of a lower limit for photosynthesis and, in fact, some experiments down to 300 nm still did not show a decrease of the absorption although it is well recognized that no photosynthesis results with 300 nm wavelengths.

  7. Solar Spectral Irradiance Variability in November/December 2012: Comparison of Observations by Instruments on the International Space Station and Models

    NASA Astrophysics Data System (ADS)

    Thuillier, G.; Schmidtke, G.; Erhardt, C.; Nikutowski, B.; Shapiro, A. I.; Bolduc, C.; Lean, J.; Krivova, N.; Charbonneau, P.; Cessateur, G.; Haberreiter, M.; Melo, S.; Delouille, V.; Mampaey, B.; Yeo, K. L.; Schmutz, W.

    2014-12-01

    Onboard the International Space Station (ISS), two instruments are observing the solar spectral irradiance (SSI) at wavelengths from 16 to 2900 nm. Although the ISS platform orientation generally precludes pointing at the Sun more than 10 - 14 days per month, in November/December 2012 a continuous period of measurements was obtained by implementing an ISS `bridging' maneuver. This enabled observations to be made of the solar spectral irradiance (SSI) during a complete solar rotation. We present these measurements, which quantify the impact of active regions on SSI, and compare them with data simultaneously gathered from other platforms, and with models of spectral irradiance variability. Our analysis demonstrates that the instruments onboard the ISS have the capability to measure SSI variations consistent with other instruments in space. A comparison among all available SSI measurements during November-December 2012 in absolute units with reconstructions using solar proxies and observed solar activity features is presented and discussed in terms of accuracy.

  8. Compatibility of internal transport barrier with steady-state operation in the high bootstrap fraction regime on DIII-D

    NASA Astrophysics Data System (ADS)

    Garofalo, A. M.; Gong, X.; Grierson, B. A.; Ren, Q.; Solomon, W. M.; Strait, E. J.; Van Zeeland, M. A.; Holcomb, C. T.; Meneghini, O.; Smith, S. P.; Staebler, G. M.; Wan, B.; Bravenec, R.; Budny, R. V.; Ding, S.; Hanson, J. M.; Heidbrink, W. W.; Lao, L. L.; Li, G.; Pan, C.; Petty, C. C.; Qian, J.; Paz-Soldan, C.; Xu, G.

    2015-11-01

    Recent EAST/DIII-D joint experiments on the high poloidal beta tokamak regime in DIII-D have demonstrated fully noninductive operation with an internal transport barrier (ITB) at large minor radius, at normalized fusion performance increased by  ⩾30% relative to earlier work (Politzer et al 2005 Nucl. Fusion 45 417). The advancement was enabled by improved understanding of the ‘relaxation oscillations’, previously attributed to repetitive ITB collapses, and of the fast ion behavior in this regime. It was found that the ‘relaxation oscillations’ are coupled core-edge modes amenable to wall-stabilization, and that fast ion losses which previously dictated a large plasma-wall separation to avoid wall over-heating, can be reduced to classical levels with sufficient plasma density. By using optimized waveforms of the plasma-wall separation and plasma density, fully noninductive plasmas have been sustained for long durations with excellent energy confinement quality, bootstrap fraction  ⩾80%, {β\\text{N}}≤slant 4 , {β\\text{P}}≥slant 3 , and {β\\text{T}}≥slant 2% . These results bolster the applicability of the high poloidal beta tokamak regime toward the realization of a steady-state fusion reactor.

  9. A method for a short-term forecast of the absorbed dose accumulation dynamics on the international space station based on radiation monitoring system data

    NASA Astrophysics Data System (ADS)

    Lishnevskii, A. E.; Benghin, V. V.

    2014-12-01

    Many papers are devoted to the prediction of radiation conditions on board of a spacecraft (Pichkhadze et al., 2004; Khamidullina et al., 2008; 2012), and a number of software systems for corresponding calculations have been developed: the US information system CREME96 (https://creme.isde.vander-bilt.edu/); European SPENVIS (http://www.spenvis.oma.be/intro.php); Russian SEREIS (Kuznetsov et al., 2001; Model' kosmosa, 2007) and COSRAD (http://cosrad.sinp.msu.ru/manual.html; Kuznetsov et al., 2011) based on the models of the radiation environment in near-Earth space (Bashkirov et al., 1998; Nymmik, 2004; Model' kosmosa, 2007; Kuznetsov et al., 2011). In this paper we propose a simple calculation algorithm of short-term (for a few days) forecasting of dynamics of the radiation dose on the International Space Station (ISS) in radiation environment undisturbed by solar proton events. This algorithm does not use radiation environment models and detailed ballistic calculations, while it uses data of the onboard radiation monitoring system (RMS) and empirical relations, obtained for ISS orbital motion.

  10. The Next Spaceflight Solar Irradiance Sensor: TSIS

    NASA Astrophysics Data System (ADS)

    Kopp, Greg; Pilewskie, Peter; Richard, Erik

    2016-05-01

    The Total and Spectral Solar Irradiance Sensor (TSIS) will continue measurements of the solar irradiance with improved accuracies and stabilities over extant spaceflight instruments. The two TSIS solar-observing instruments include the Total Irradiance Monitor (TIM) and the Spectral Irradiance Monitor (SIM) for measuring total- and spectral- solar-irradiance, respectively. The former provides the net energy powering the Earth’s climate system while the latter helps attribute where that energy is absorbed by the Earth’s atmosphere and surface. Both spaceflight instruments are assembled and being prepared for integration on the International Space Station. With operations commencing in late 2017, the TSIS is intended to overlap with NASA’s ongoing SOlar Radiation and Climate Experiment (SORCE) mission, which launched in 2003 and contains the first versions of both the TIM and SIM instruments, as well as with the TSI Calibration Transfer Experiment (TCTE), which began total solar irradiance measurements in 2013. We summarize the TSIS’s instrument improvements and intended solar-irradiance measurements.

  11. Advanced neutron absorber materials

    DOEpatents

    Branagan, Daniel J.; Smolik, Galen R.

    2000-01-01

    A neutron absorbing material and method utilizing rare earth elements such as gadolinium, europium and samarium to form metallic glasses and/or noble base nano/microcrystalline materials, the neutron absorbing material having a combination of superior neutron capture cross sections coupled with enhanced resistance to corrosion, oxidation and leaching.

  12. Multispectral metamaterial absorber.

    PubMed

    Grant, J; McCrindle, I J H; Li, C; Cumming, D R S

    2014-03-01

    We present the simulation, implementation, and measurement of a multispectral metamaterial absorber (MSMMA) and show that we can realize a simple absorber structure that operates in the mid-IR and terahertz (THz) bands. By embedding an IR metamaterial absorber layer into a standard THz metamaterial absorber stack, a narrowband resonance is induced at a wavelength of 4.3 μm. This resonance is in addition to the THz metamaterial absorption resonance at 109 μm (2.75 THz). We demonstrate the inherent scalability and versatility of our MSMMA by describing a second device whereby the MM-induced IR absorption peak frequency is tuned by varying the IR absorber geometry. Such a MSMMA could be coupled with a suitable sensor and formed into a focal plane array, enabling multispectral imaging. PMID:24690713

  13. Effect of Nodal Irradiation and Fraction Size on Cardiac and Cerebrovascular Mortality in Women With Breast Cancer Treated With Local and Locoregional Radiotherapy

    SciTech Connect

    Stokes, Erika L.; Tyldesley, Scott; Woods, Ryan; Wai, Elaine; Olivotto, Ivo A.

    2011-06-01

    Purpose: To determine whether the adjuvant breast cancer radiation volume or fraction size (>2 Gy vs. {<=}2 Gy) affected the risk of fatal cardiac or cerebrovascular (CCV) events and to determine whether the addition of regional radiotherapy (RT) increased the risk of fatal cerebrovascular events compared with breast/chest wall RT alone. Methods and Materials: Overall survival was compared for patients receiving breast/chest wall RT alone or breast/chest wall plus regional node RT (BRCW+NRT) in a population-based cohort of women with early-stage breast cancer who had undergone RT between 1990 and 1996. The effect of laterality, age, systemic therapy, radiation volume, and fraction size on the risk of fatal CCV events was analyzed using a competing risk method. Results: A total of 4,929 women underwent adjuvant RT. The median follow-up was 11.7 years. BRCW+NRT was associated with an increased risk of CCV death at 12 years (5% for BRCW+NRT vs. 3.5% for breast/chest wall RT alone; p = .004), but the fraction size was not (3.92% for a fraction size >2 Gy vs. 3.54% for a fraction size <2 Gy; p = .83). The 12-year absolute risk of death from stroke alone did not differ for either radiation volume (1.17% for BRCW+NRT vs. 0.8% for breast/chest wall RT alone; p = .22) or fraction size (p = .59). Conclusion: Regional RT was associated with a small (1.5% at 12 years), but statistically significant, increased risk of death from a CCV event. The addition of regional RT did not significantly increase the risk of death from stroke, although the number of events was small. An increased fraction size was not significantly associated with a greater risk of fatal CCV events. These data support the continued use of hypofractionated adjuvant regional RT.

  14. Metal shearing energy absorber

    NASA Technical Reports Server (NTRS)

    Fay, R. J.; Wittrock, E. P. (Inventor)

    1973-01-01

    A metal shearing energy absorber is described. The absorber is composed of a flat thin strip of metal which is pulled through a slot in a cutter member of a metal, harder than the metal of the strip. The slot's length, in the direction perpendicular to the pull direction, is less than the strip's width so that as the strip is pulled through the slot, its edges are sheared off, thereby absorbing some of the pulling energy. In one embodiment the cutter member is a flat plate of steel, while in another embodiment the cutter member is U-shaped with the slot at its base.

  15. Lipid-absorbing Polymers

    NASA Technical Reports Server (NTRS)

    Marsh, H. E., Jr.; Wallace, C. J.

    1973-01-01

    The removal of bile acids and cholesterol by polymeric absorption is discussed in terms of micelle-polymer interaction. The results obtained with a polymer composed of 75 parts PEO and 25 parts PB plus curing ingredients show an absorption of 305 to 309%, based on original polymer weight. Particle size effects on absorption rate are analyzed. It is concluded that crosslinked polyethylene oxide polymers will absorb water, crosslinked polybutadiene polymers will absorb lipids; neither polymer will absorb appreciable amounts of lipids from micellar solutions of lipids in water.

  16. An improved characterization method for international accountancy measurements of fresh and irradiated mixed oxide (MOX) fuel: helping achieve continual monitoring and safeguards through the fuel cycle

    SciTech Connect

    Evans, Louise G; Croft, Stephen; Swinhoe, Martyn T; Tobin, S. J.; Menlove, H. O.; Schear, M. A.; Worrall, Andrew

    2011-01-13

    Nuclear fuel accountancy measurements are conducted at several points through the nuclear fuel cycle to ensure continuity of knowledge (CofK) of special nuclear material (SNM). Non-destructive assay (NDA) measurements are performed on fresh fuel (prior to irradiation in a reactor) and spent nuclear fuel (SNF) post-irradiation. We have developed a fuel assembly characterization system, based on the novel concept of 'neutron fingerprinting' with multiplicity signatures to ensure detailed CofK of nuclear fuel through the entire fuel cycle. The neutron fingerprint in this case is determined by the measurement of the various correlated neutron signatures, specific to fuel isotopic composition, and therefore offers greater sensitivity to variations in fissile content among fuel assemblies than other techniques such as gross neutron counting. This neutron fingerprint could be measured at the point of fuel dispatch (e.g. from a fuel fabrication plant prior to irradiation, or from a reactor site post-irradiation), monitored during transportation of the fuel assembly, and measured at a subsequent receiving site (e.g. at the reactor site prior to irradiation, or reprocessing facility post-irradiation); this would confirm that no unexpected changes to the fuel composition or amount have taken place during transportation and/ or reactor operations. Changes may indicate an attempt to divert material for example. Here, we present the current state of the practice of fuel measurements for both fresh mixed oxide (MOX) fuel and SNF (both MOX and uranium dioxide). This is presented in the framework of international safeguards perspectives from the US and UK. We also postulate as to how the neutron fingerprinting concept could lead to improved fuel characterization (both fresh MOX and SNF) resulting in: (a) assured CofK of fuel across the nuclear fuel cycle, (b) improved detection of SNM diversion, and (c) greater confidence in safeguards of SNF transportation.

  17. An improved characterization method for international accountancy measurements of fresh and irradiated mixed oxide (MOX) fuel: helping achieve continual monitoring and safeguards through the fuel cycle

    SciTech Connect

    Evans, Louise G; Croft, Stephen; Swinhoe, Martyn T; Tobin, S. J.; Boyer, B. D.; Menlove, H. O.; Schear, M. A.; Worrall, Andrew

    2010-11-24

    Nuclear fuel accountancy measurements are conducted at several points through the nuclear fuel cycle to ensure continuity of knowledge (CofK) of special nuclear material (SNM). Non-destructive assay (NDA) measurements are performed on fresh fuel (prior to irradiation in a reactor) and spent nuclear fuel (SNF) post-irradiation. We have developed a fuel assembly characterization system, based on the novel concept of 'neutron fingerprinting' with multiplicity signatures to ensure detailed CofK of nuclear fuel through the entire fuel cycle. The neutron fingerprint in this case is determined by the measurement of the various correlated neutron signatures, specific to fuel isotopic composition, and therefore offers greater sensitivity to variations in fissile content among fuel assemblies than other techniques such as gross neutron counting. This neutron fingerprint could be measured at the point of fuel dispatch (e.g. from a fuel fabrication plant prior to irradiation, or from a reactor site post-irradiation), monitored during transportation of the fuel assembly, and measured at a subsequent receiving site (e.g. at the reactor site prior to irradiation, or reprocessing facility post-irradiation); this would confirm that no unexpected changes to the fuel composition or amount have taken place during transportation and/or reactor operations. Changes may indicate an attempt to divert material for example. Here, we present the current state of the practice of fuel measurements for both fresh mixed oxide (MOX) fuel and SNF (both MOX and uranium dioxide). This is presented in the framework of international safeguards perspectives from the US and UK. We also postulate as to how the neutron fingerprinting concept could lead to improved fuel characterization (both fresh MOX and SNF) resulting in: (a) assured CofK of fuel across the nuclear fuel cycle, (b) improved detection of SNM diversion, and (c) greater confidence in safeguards of SNF transportation.

  18. Dyeing behaviour of gamma irradiated cotton fabric using Lawson dye extracted from henna leaves (Lawsonia inermis)

    NASA Astrophysics Data System (ADS)

    Rehman, Fazal-ur; Adeel, Shahid; Qaiser, Summia; Ahmad Bhatti, Ijaz; Shahid, Muhammad; Zuber, Mohammad

    2012-11-01

    Dyeing behavior of gamma irradiated cotton fabric using Lawson dye extracted from henna leaves has been investigated. Cotton and dye powder are irradiated to different absorbed doses of 2, 4, 6, 8 and 10 kGy using Cs-137 gamma irradiator. The dyeing parameters such as dyeing time, electrolyte (salt) concentration and mordant concentrations using copper and iron as mordants are optimized. Dyeing is performed using un-irradiated and irradiated cotton with dye solutions and their color strength values are evaluated in CIE Lab system using Spectraflash -SF650. Methods suggested by International Standard Organization (ISO) have been employed to investigate the colourfastness properties such as colourfastness to light, washing and rubbing of irradiated dyed fabric. It is found that gamma ray treatment of cotton dyed with extracts of henna leaves has significantly improved the color strength as well as enhanced the rating of fastness properties.

  19. The MIRD method of estimating absorbed dose

    SciTech Connect

    Weber, D.A.

    1991-01-01

    The estimate of absorbed radiation dose from internal emitters provides the information required to assess the radiation risk associated with the administration of radiopharmaceuticals for medical applications. The MIRD (Medical Internal Radiation Dose) system of dose calculation provides a systematic approach to combining the biologic distribution data and clearance data of radiopharmaceuticals and the physical properties of radionuclides to obtain dose estimates. This tutorial presents a review of the MIRD schema, the derivation of the equations used to calculate absorbed dose, and shows how the MIRD schema can be applied to estimate dose from radiopharmaceuticals used in nuclear medicine.

  20. "Smart" Electromechanical Shock Absorber

    NASA Technical Reports Server (NTRS)

    Stokes, Lebarian; Glenn, Dean C.; Carroll, Monty B.

    1989-01-01

    Shock-absorbing apparatus includes electromechanical actuator and digital feedback control circuitry rather than springs and hydraulic damping as in conventional shock absorbers. Device not subject to leakage and requires little or no maintenance. Attenuator parameters adjusted in response to sensory feedback and predictive algorithms to obtain desired damping characteristic. Device programmed to decelerate slowly approaching vehicle or other large object according to prescribed damping characteristic.

  1. Iron Chalcogenide Photovoltaic Absorbers

    SciTech Connect

    Yu, Liping; Lany, Stephan; Kykyneshi, Robert; Jieratum, Vorranutch; Ravichandran, Ram; Pelatt, Brian; Altschul, Emmeline; Platt, Heather A. S.; Wager, John F.; Keszler, Douglas A.; Zunger, Alex

    2011-08-10

    An integrated computational and experimental study of FeS₂ pyrite reveals that phase coexistence is an important factor limiting performance as a thin-film solar absorber. This phase coexistence is suppressed with the ternary materials Fe₂SiS₄ and Fe₂GeS₄, which also exhibit higher band gaps than FeS₂. Thus, the ternaries provide a new entry point for development of thin-film absorbers and high-efficiency photovoltaics.

  2. Decreased DAB2IP gene expression, which could be induced by fractionated irradiation, is associated with resistance to γ‑rays and α‑particles in prostate cancer cells.

    PubMed

    Yang, Chen; He, Hui; Zhang, Tingting; Chen, Ying; Kong, Zhaolu

    2016-07-01

    External beam radiation therapy, alone or combined with androgen deprivation, is a well‑established treatment for prostate cancer (PCa). However, not all patients benefit from radiotherapy due to congenital or acquired radioresistance. The preliminary results of the present study indicated that the loss of disabled homolog 2 interactive protein (DAB2IP) expression in PCa and normal prostate epithelia results in the resistance to γ‑rays. To further explore the association between DAB2IP and ionizing radiation (IR), PCa cells were fractionally irradiated 12 times with 2 Gy of γ‑rays and the change in DAB2IP mRNA expression was monitored. Notably, along with a continuous reduction of DAB2IP expression levels, increased expression levels of ataxia‑telangiectasia mutated (ATM) was observed in IR‑treated cells. In order to improve the sensitivity of DAB2IP‑deficient cells to IR, α‑particles, a type of high linear energy transfer radiation and KU55933, an ATM inhibitor, were used in the current study. It was determined that α‑particle irradiations were more effective than γ‑rays on cells expressing expected and decreased levels of DAB2IP. However, cells with a dysfunctional DAB2IP gene were resistant to α‑particle irradiation. Treatment with KU55933 did not enhance cell sensitivity to α‑irradiation. Therefore, this suggested that DAB2IP downregulation induced by radiotherapy may be associated with acquired radioresistance in patients with PCa. PMID:27177018

  3. Food irradiation and sterilization

    NASA Astrophysics Data System (ADS)

    Josephson, Edward S.

    Radiation sterilization of food (radappertization) requires exposing food in sealed containers to ionizing radiation at absorbed doses high enough (25-70 kGy) to kill all organisms of food spoilage and public health significance. Radappertization is analogous to thermal canning is achieving shelf stability (long term storage without refrigeration). Except for dry products in which autolysis is negligible, the radappertization process also requires that the food be heated to an internal temperature of 70-80°C (bacon to 53°C) to inactivate autolytic enzymes which catalyze spoilage during storage without refrigeration. To minimize the occurence of irradiation induced off-flavors and odors, undesirable color changes, and textural and nutritional losses from exposure to the high doses required for radappertization, the foods are vacuum sealed and irradiated frozen (-40°C to -20°C). Radappertozed foods have the characteristic of fresh foods prepared for eating. Radappertization can substitute in whole or in part for some chemical food additives such as ethylene oxide and nitrites which are either toxic, carcinogenic, mutagenic, or teratogenic. After 27 years of testing for "wholesomeness" (safety for consumption) of radappertized foods, no confirmed evidence has been obtained of any adverse effecys of radappertization on the "wholesomeness" characteristics of these foods.

  4. On-Going International Research Program on Irradiated Concrete Conducted by DOE, EPRI and Japan Research Institutions. Roadmap, Achievements and Path Forward

    SciTech Connect

    Le Pape, Yann; Rosseel, Thomas M.

    2015-10-01

    The Joint Department of Energy (DOE)-Electric Power Research Institute (EPRI) Program (Light Water Reactor Sustainability (LWRS) Program–Material Pathway–Concrete and Long-Term Operation (LTO) Program) and US Nuclear Regulatory Commission (NRC) research studies aim at understanding the most prominent degradation modes and their effects on the long-term operation of concrete structures to nuclear power generation. Based on the results of the Expanded Materials Degradation Analysis (EMDA), (NUREG/CR-7153, ORNL/TM-2011/545), irradiated concrete and alkali-silica reaction (ASR)-affected concrete structures are the two prioritized topics of on-going research. This report focuses specifically on the topic of irradiated concrete and summarizes the main accomplishments obtained by this joint program, but also provides an overview of current relevant activities domestically and internationally. Possible paths forward are also suggested to help near-future orientation of this program.

  5. Effects of aqueous-soluble organic compounds on the removal of selected radionuclides from high-level waste part I: Distribution of Sr, Cs, and Tc onto 18 absorbers from an irradiated, organic-containing leachate simulant for Hanford Tank 101-SY

    SciTech Connect

    Marsh, S.F.; Svitra, Z.V.; Bowen, S.M.

    1995-01-01

    Many of the radioactive waste storage tanks at U.S. Department of Energy facilities contain organic compounds that have been degraded by radiolysis and chemical reactions. In this investigation, we measured the effect of some aqueous-soluble organic compounds on the sorption of strontium, cesium, and technetium onto 18 absorbers that offer high sorption of strontium from organic-free solutions. For our test solution we used a leachate from a simulated slurry for Hanford Tank 101-SY that initially contained ethylenediaminetetraacetic acid (EDTA) and then was gamma-irradiated to 34 Mrads. We measured distribution coefficients (Kds) for each element/absorber combination for dynamic contact periods of 30 min, 2 h, and 6 h to obtain information about sorption kinetics. To facilitate comparisons, we include Kd values for these same element/absorber combinations from three organic-free simulant solutions. The Kd values for strontium sorption from the simulant that contained the degraded organics usually decreased by large factors, whereas the Kd values for cesium and technetium sorption were relatively unaffected.

  6. Simultaneous experimental determination of labile proton fraction ratio and exchange rate with irradiation radio frequency power-dependent quantitative CEST MRI analysis.

    PubMed

    Sun, Phillip Zhe; Wang, Yu; Xiao, Gang; Wu, Renhua

    2013-01-01

    Chemical exchange saturation transfer (CEST) imaging is sensitive to dilute proteins/peptides and microenvironmental properties, and has been increasingly evaluated for molecular imaging and in vivo applications. However, the experimentally measured CEST effect depends on the CEST agent concentration, exchange rate and relaxation time. In addition, there may be non-negligible direct radio-frequency (RF) saturation effects, particularly severe for diamagnetic CEST (DIACEST) agents owing to their relatively small chemical shift difference from that of the bulk water resonance. As such, the commonly used asymmetry analysis only provides CEST-weighted information. Recently, it has been shown with numerical simulation that both labile proton concentration and exchange rate can be determined by evaluating the RF power dependence of DIACEST effect. To validate the simulation results, we prepared and imaged two CEST phantoms: a pH phantom of serially titrated pH at a fixed creatine concentration and a concentration phantom of serially varied creatine concentration titrated to the same pH, and solved the labile proton fraction ratio and exchange rate per-pixel. For the concentration phantom, we showed that the labile proton fraction ratio is proportional to the CEST agent concentration with negligible change in the exchange rate. Additionally, we found the exchange rate of the pH phantom is dominantly base-catalyzed with little difference in the labile proton fraction ratio. In summary, our study demonstrated quantitative DIACEST MRI, which remains promising to augment the conventional CEST-weighted MRI analysis. PMID:23606428

  7. Simultaneous determination of labile proton fraction ratio and exchange rate with irradiation radio frequency (RF) power dependent quantitative CEST MRI analysis

    PubMed Central

    Sun, Phillip Zhe; Wang, Yu; Xiao, Gang; Wu, Renhua

    2014-01-01

    Chemical exchange saturation transfer (CEST) imaging is sensitive to dilute proteins/peptides and microenvironmental properties, and has been increasingly evaluated for molecular imaging and in vivo applications. However, the experimentally measured CEST effect depends on the CEST agent concentration, exchange rate and relaxation time. In addition, there may be non-negligible direct radio-frequency (RF) saturation effects, particularly severe for diamagnetic CEST (DIACEST) agents due to their relatively small chemical shift difference from that of the bulk water resonance. As such, the commonly used asymmetry analysis only provides CEST-weighted information. Recently, it has been shown with numerical simulation that both labile proton concentration and exchange rate can be determined by evaluating the RF power dependence of DIACEST effect. To validate the simulation results, we prepared and imaged two CEST phantoms: a pH phantom of serially titrated pH at a fixed creatine concentration and a concentration phantom of serially varied creatine concentration titrated to the same pH, and solved the labile proton fraction ratio and exchange rate per-pixel. For the concentration phantom, we showed that the labile proton fraction ratio is proportional to the CEST agent concentration with negligible change in the exchange rate. Additionally, we found the exchange rate of the pH phantom is dominantly base-catalyzed with little difference in the labile proton fraction ratio. In summary, our study demonstrated quantitative DIACEST MRI, which remains promising to augment the conventional CEST-weighted MRI analysis. PMID:23606428

  8. Unidirectional perfect absorber.

    PubMed

    Jin, L; Wang, P; Song, Z

    2016-01-01

    This study proposes a unidirectional perfect absorber (UPA), which we realized with a two-arm Aharonov-Bohm interferometer, that consists of a dissipative resonator side-coupled to a uniform resonator array. The UPA has reflection-less full absorption on one direction, and reflectionless full transmission on the other, with an appropriate magnetic flux and coupling, detuning, and loss of the side-coupled resonator. The magnetic flux controls the transmission, the left transmission is larger for magnetic flux less than one-half flux quantum; and the right transmission is larger for magnetic flux between one-half and one flux quantum. Besides, a perfect absorber (PA) can be realized based on the UPA, in which light waves from both sides, with arbitrary superposition of the ampli- tude and phase, are perfectly absorbed. The UPA is expected to be useful in the design of novel optical devices. PMID:27615125

  9. Multiple-layer Radiation Absorber

    NASA Astrophysics Data System (ADS)

    Baker, Robert M. L.; Baker, Bonnie Sue

    A structure is discussed for absorbing incident radiation, either electromagnetic (EM) or sound. Such a surface structure is needed, for example, in a highly sensitive high-frequency gravitational wave or HFGW detector such as the Li-Baker. The multi-layer absorber, which is discussed, is constructed with metamaterial [MM] layer or layers on top. This MM is configured for a specific EM or sound radiation frequency band, which absorbs incident EM or sound radiation without reflection. Below these top MM layers is a substrate of conventional EM-radiation absorbing or acoustical absorbing reflective material, such as an array of pyramidal foam absorbers. Incident radiation is partially absorbed by the MM layer or layers, and then it is more absorbed by the lower absorbing and reflecting substrate. The remaining reflected radiation is even further absorbed by the MM layers on its "way out_ so that essentially all of the incident radiation is absorbed _ a nearly perfect black-body absorber. In a HFGW detector a substrate, such as foam absorbers, may outgas into a high vacuum and reduce the capability of the vacuum-producing equipment, however, the layers above this lowest substrate will seal the absorbing and reflecting substrate from any external vacuum. The layers also serve to seal the absorbing material against air or water flow past the surfaces of aircraft, watercraft or submarines. Other applications for such a multiple-level radiation absorber include stealth aircraft, missiles and submarines.

  10. Neutron Absorbing Alloys

    DOEpatents

    Mizia, Ronald E.; Shaber, Eric L.; DuPont, John N.; Robino, Charles V.; Williams, David B.

    2004-05-04

    The present invention is drawn to new classes of advanced neutron absorbing structural materials for use in spent nuclear fuel applications requiring structural strength, weldability, and long term corrosion resistance. Particularly, an austenitic stainless steel alloy containing gadolinium and less than 5% of a ferrite content is disclosed. Additionally, a nickel-based alloy containing gadolinium and greater than 50% nickel is also disclosed.

  11. Alternatives to dose, quality factor and dose equivalent for low level irradiation

    SciTech Connect

    Sondhaus, C.A.; Bond, V.P.; Feinendegen, L.E.

    1988-01-01

    Randomly occurring energy deposition events produced by low levels of ionizing radiation interacting with tissue deliver variable amounts of energy to the sensitive target volumes within a small fraction of the cell population. A model is described in which an experimentally derived function relating event size to cell response probability operates mathematically on the microdosimetric event size distribution characterizing a given irradiation and thus determines the total fractional number of responding cells; this fraction measures the effectiveness of the given radiation. Normalizing to equal numbers of events produced by different radiations and applying this cell response or hit size effectiveness function (HSEF) should define radiation quality, or relative effectiveness, on a more nearly absolute basis than do the absorbed dose and dose evaluation, which are confounded when applied to low level irradiations. Examples using both calculation and experimental data are presented. 15 refs., 18 figs.

  12. An extremely wideband and lightweight metamaterial absorber

    PubMed Central

    Shen, Yang; Pei, Zhibin; Pang, Yongqiang; Wang, Jiafu; Zhang, Anxue; Qu, Shaobo

    2015-01-01

    This paper presents a three-dimensional microwave metamaterial absorber based on the stand-up resistive film patch array. The absorber has wideband absorption, lightweight, and polarization-independent properties. Our design comes from the array of unidirectional stand-up resistive film patches backed by a metallic plane, which can excite multiple standing wave modes. By rolling the resistive film patches as a square enclosure, we obtain the polarization-independent property. Due to the multiple standing wave modes, the most incident energy is dissipated by the resistive film patches, and thus, the ultra-wideband absorption can be achieved by overlapping all the absorption modes at different frequencies. Both the simulated and experimental results show that the absorber possesses a fractional bandwidth of 148.2% with the absorption above 90% in the frequency range from 3.9 to 26.2 GHz. Moreover, the proposed absorber is extremely lightweight. The areal density of the fabricated sample is about 0.062 g/cm2, which is approximately equivalent to that of eight stacked standard A4 office papers. It is expected that our proposed absorber may find potential applications such as electromagnetic interference and stealth technologies. PMID:26130845

  13. An extremely wideband and lightweight metamaterial absorber

    NASA Astrophysics Data System (ADS)

    Shen, Yang; Pei, Zhibin; Pang, Yongqiang; Wang, Jiafu; Zhang, Anxue; Qu, Shaobo

    2015-06-01

    This paper presents a three-dimensional microwave metamaterial absorber based on the stand-up resistive film patch array. The absorber has wideband absorption, lightweight, and polarization-independent properties. Our design comes from the array of unidirectional stand-up resistive film patches backed by a metallic plane, which can excite multiple standing wave modes. By rolling the resistive film patches as a square enclosure, we obtain the polarization-independent property. Due to the multiple standing wave modes, the most incident energy is dissipated by the resistive film patches, and thus, the ultra-wideband absorption can be achieved by overlapping all the absorption modes at different frequencies. Both the simulated and experimental results show that the absorber possesses a fractional bandwidth of 148.2% with the absorption above 90% in the frequency range from 3.9 to 26.2 GHz. Moreover, the proposed absorber is extremely lightweight. The areal density of the fabricated sample is about 0.062 g/cm2, which is approximately equivalent to that of eight stacked standard A4 office papers. It is expected that our proposed absorber may find potential applications such as electromagnetic interference and stealth technologies.

  14. External and internal irradiation of a rural Bryansk (Russia) population from 1990 to 2000, following high deposition of radioactive caesium from the Chernobyl accident.

    PubMed

    Thornberg, C; Vesanen, R; Wallström, E; Zvonova, I; Jesko, T; Balonov, M; Mattsson, S

    2005-10-01

    In 1990, a joint Nordic-Russian project was initiated in order to make independent estimations of the effective dose to selected groups of inhabitants in a highly contaminated area around the city of Novozybkov in the western Bryansk region of Russia. The inhabitants were living in six villages with initial contamination levels of (137)Cs between 0.9 and 2.7 MBq m(-2). Some villages had been decontaminated, others not. Both school children and adults participated in the study. The external irradiation of 100-130 inhabitants was determined during 1 month in September-October each year from 1990 to 2000 (except 1999), using individual thermoluminescent dosemeters. The body burden of (137,134)Cs was determined by in vivo measurements in about 500 inhabitants annually from 1991 to 2000, and for a subgroup also with analysis of the (137)Cs concentration in urine. The mean effective dose (E) from external and internal irradiation due to (137,134)Cs deposition varied between 2.5 and 1.2 mSv per year between 1990 and 2000. The total mean E decreased, on average, by 9% per year, while the mean external dose decreased by 16% per year. The dose rate from internal radiation decreased more slowly than the dose rate from external radiation, and also showed an irregular time variation. The contribution from the internal dose to the total E was 30-50%, depending on the village. Predictions for the long-term changes in the effective dose to people living in the areas are presented. The cumulated E for the 70 years following the accident was estimated to be about 90 mSv with the assumption that both internal and external dose decrease by 2% per year after year 2000. The highest E during a life-time received by single individuals living in the area may amount to around 500 mSv considering the individual variations in E. PMID:16175396

  15. Solar Irradiance Variation and the Response of the Upper Atmosphere - A Review of Recent Progress in the International TIGER Program

    NASA Astrophysics Data System (ADS)

    Solomon, Stanley

    Solar irradiance in the ultraviolet, extreme-ultraviolet, and X-ray spectral regions are a key determinant of the state and variation of upper atmosphere and ionosphere parameters, including densities, temperatures, composition, photoelectron fluxes, airglow emission processes, and magnetosphere-ionosphere coupling. The Thermosphere-Ionosphere-Geosphere Research (TIGER) program was established in 1998 with the objective of obtaining a better quantitative understanding of variations in solar irradiance and the effects on the upper atmosphere. The TIGER program has contributed to progress in this area through an ongoing series of conferences, workshops, publications, and data exchange. Advances in measurement and modeling of the solar spectrum have led to improved understanding of the atmosphere/ionosphere response, and to closure between models and measurements in several areas. In this paper, a brief overview of recent results is provided, some critical outstanding questions are identified, and the prospects for new solar and terrestrial observational programs are described.

  16. Antifungal impact of volatile fractions of Peumus boldus and Lippia turbinata on Aspergillus section Flavi and residual levels of these oils in irradiated peanut.

    PubMed

    Passone, María Alejandra; Etcheverry, Miriam

    2014-01-01

    To investigate the antifungal properties of essential oil (EO) vapors from boldo and poleo on Aspergillus section Flavi and the residual levels of the oils in peanut, irradiated peanuts conditioned at three water activities (0.98, 0.95, 0.93) were treated with 2 and 3 μL/g of boldo and 3 and 5 μL/g of poleo. EO treatments produced the greatest impact on fungal growth parameters, followed by oil concentrations and aW levels. The three main components in peanut exposed to oil vapors were piperitone oxide, α-terpinene and eucalyptol for boldo and β-caryophyllene epoxide, limonene and piperitenone for poleo. Residues of boldo and poleo EO were significantly decreased from 24.7 to 100% and from 26.6 to 99.7% at the end of the incubation period, respectively. The application of nontoxic boldo oil as fumigant in the control of Aspergillus section Flavi may represent a potential alternative antifungal treatment, without significant residues after 35 days. PMID:24211775

  17. Laser Assisted Cancer Immunotherapy: Surface Irradiation

    NASA Astrophysics Data System (ADS)

    Wilson, Joshua; Chen, Hsin-Wei; Bandyopadhyay, Pradip

    2006-03-01

    Experiments in our laboratory incorporate a non-invasive approach to treat superficial tumors in animal models. Based on the concept of Laser Assisted Cancer Immunotherapy, surface irradiation provides good information to compare to invasive alternatives. The procedure involves injecting an immunoadjuvant (Glycated Chitosan) as well as a light absorbing dye (Indocyanine Green) directly into the tumor (5 to 7 mm in diameter). The temperature of the tumor is raised using an infrared diode laser operating at 804 nm, with a silica fiber tip placed a set distance away from the surface of the tumor. We monitor the surface temperature using non-invasive (infrared detector probe) as well as the internal temperature of the tumor using invasive (micro thermocouples) methods. This study aims at the success of the surface irradiation mode to treat solid tumors. * This work is supported by a grant from The National Institute of Health.

  18. MODIS Measures Fraction of Sunlight Absorbed by Plants

    NASA Technical Reports Server (NTRS)

    2002-01-01

    At the height of the solar cycle, the Sun is finally displaying some fireworks. This image from the Solar and Heliospheric Observatory (SOHO) shows a large solar flare from June 6, 2000 at 1424 Universal Time (10:24 AM Eastern Daylight Savings Time). Associated with the flare was a coronal mass ejection that sent a wave of fast moving charged particles straight towards Earth. (The image was acquired by the Extreme ultaviolet Imaging Telescope (EIT), one of 12 instruments aboard SOHO) Solar activity affects the Earth in several ways. The particles generated by flares can disrupt satellite communications and interfere with power transmission on the Earth's surface. Earth's climate is tied to the total energy emitted by the sun, cooling when the sun radiates less energy and warming when solar output increases. Solar radiation also produces ozone in the stratosphere, so total ozone levels tend to increase during the solar maximum. For more information about these solar flares and the SOHO mission, see NASA Science News or the SOHO home page. For more about the links between the sun and climate change, see Sunspots and the Solar Max. Image courtesy SOHO Extreme ultaviolet Imaging Telescope, ESA/NASA

  19. Solar absorber material stability under high solar flux

    NASA Astrophysics Data System (ADS)

    Ignatiev, A.; Zajac, G.; Smith, G. B.

    1982-04-01

    Solar absorbing Black Chrome coatings have been exposed to high temperatures (350-400 C) under high solar fluxes (0.4 to 2.0 MW/sq m) to test for their stability under actual operating conditions. Field tests at the White Sands Solar Furnace have shown higher stability than expected from oven tested samples. Laboratory studies utilizing spectrally selective concentrated solar simulated radiation have indicated that the cause of the higher stability under solar irradiation is photo-stimulated desorption of oxygen bearing species at the absorber surface and resultant reduced oxidation of the absorber.

  20. Metasurface Broadband Solar Absorber

    DOE PAGESBeta

    Azad, Abul K.; Kort-Kamp, Wilton J. M.; Sykora, Milan; Weisse-Bernstein, Nina R.; Luk, Ting S.; Taylor, Antoinette J.; Dalvit, Diego A. R.; Chen, Hou-Tong

    2016-02-01

    Here, we demonstrate a broadband, polarization independent, wide-angle absorber based on a metallic metasurface architecture, which accomplishes greater than 90% absorptance in the visible and near-infrared range of the solar spectrum, and exhibits low absorptivity (emissivity) at mid- and far-infrared wavelengths. The complex unit cell of the metasurface solar absorber consists of eight pairs of gold nano-resonators that are separated from a gold ground plane by a thin silicon dioxide spacer. Moreover, our experimental measurements reveal high-performance absorption over a wide range of incidence angles for both s- and p-polarizations. We also investigate numerically the frequency-dependent field and current distributionsmore » to elucidate how the absorption occurs within the metasurface structure.« less

  1. Metasurface Broadband Solar Absorber

    PubMed Central

    Azad, Abul K.; Kort-Kamp, Wilton J. M.; Sykora, Milan; Weisse-Bernstein, Nina R.; Luk, Ting S.; Taylor, Antoinette J.; Dalvit, Diego A. R.; Chen, Hou-Tong

    2016-01-01

    We demonstrate a broadband, polarization independent, wide-angle absorber based on a metallic metasurface architecture, which accomplishes greater than 90% absorptance in the visible and near-infrared range of the solar spectrum, and exhibits low absorptivity (emissivity) at mid- and far-infrared wavelengths. The complex unit cell of the metasurface solar absorber consists of eight pairs of gold nano-resonators that are separated from a gold ground plane by a thin silicon dioxide spacer. Our experimental measurements reveal high-performance absorption over a wide range of incidence angles for both s- and p-polarizations. We also investigate numerically the frequency-dependent field and current distributions to elucidate how the absorption occurs within the metasurface structure. PMID:26828999

  2. Metasurface Broadband Solar Absorber

    NASA Astrophysics Data System (ADS)

    Azad, Abul K.; Kort-Kamp, Wilton J. M.; Sykora, Milan; Weisse-Bernstein, Nina R.; Luk, Ting S.; Taylor, Antoinette J.; Dalvit, Diego A. R.; Chen, Hou-Tong

    2016-02-01

    We demonstrate a broadband, polarization independent, wide-angle absorber based on a metallic metasurface architecture, which accomplishes greater than 90% absorptance in the visible and near-infrared range of the solar spectrum, and exhibits low absorptivity (emissivity) at mid- and far-infrared wavelengths. The complex unit cell of the metasurface solar absorber consists of eight pairs of gold nano-resonators that are separated from a gold ground plane by a thin silicon dioxide spacer. Our experimental measurements reveal high-performance absorption over a wide range of incidence angles for both s- and p-polarizations. We also investigate numerically the frequency-dependent field and current distributions to elucidate how the absorption occurs within the metasurface structure.

  3. Metasurface Broadband Solar Absorber.

    PubMed

    Azad, Abul K; Kort-Kamp, Wilton J M; Sykora, Milan; Weisse-Bernstein, Nina R; Luk, Ting S; Taylor, Antoinette J; Dalvit, Diego A R; Chen, Hou-Tong

    2016-01-01

    We demonstrate a broadband, polarization independent, wide-angle absorber based on a metallic metasurface architecture, which accomplishes greater than 90% absorptance in the visible and near-infrared range of the solar spectrum, and exhibits low absorptivity (emissivity) at mid- and far-infrared wavelengths. The complex unit cell of the metasurface solar absorber consists of eight pairs of gold nano-resonators that are separated from a gold ground plane by a thin silicon dioxide spacer. Our experimental measurements reveal high-performance absorption over a wide range of incidence angles for both s- and p-polarizations. We also investigate numerically the frequency-dependent field and current distributions to elucidate how the absorption occurs within the metasurface structure. PMID:26828999

  4. Naval Reactors Prime Contractor Team (NRPCT) Experiences and Considerations With Irradiation Test Performance in an International Environment

    SciTech Connect

    MH Lane

    2006-02-15

    This letter forwards a compilation of knowledge gained regarding international interactions and issues associated with Project Prometheus. The following topics are discussed herein: (1) Assessment of international fast reactor capability and availability; (2) Japanese fast reactor (JOYO) contracting strategy; (3) NRPCT/Program Office international contract follow; (4) Completion of the Japan Atomic Energy Agency (JAEA)/Pacific Northwest National Laboratory (PNNL) contract for manufacture of reactor test components; (5) US/Japanese Departmental interactions and required Treaties and Agreements; and (6) Non-technical details--interactions and considerations.

  5. Ionized Absorbers in AGN

    NASA Astrophysics Data System (ADS)

    Mathur, S.

    1999-08-01

    As a part of this program, we observed three AGN:PKS2251 + 113, PG0043 = 039 and PLH909. Two objects show signatures of absorbtion in their UV spectra. Based on our earlier modeling of X-ray warm absorbents, we expected to observe X-ray observation in these objects. The third, PLH909, is known to have soft excess in EINSTEIN data. Attachment: "Exploratory ASCA observation of broad absorption line quasi-stellar objects".

  6. Ionized Absorbers in AGN

    NASA Technical Reports Server (NTRS)

    Mathur, S.

    1999-01-01

    As a part of this program, we observed three AGN:PKS2251 + 113, PG0043 = 039 and PLH909. Two objects show signatures of absorbtion in their UV spectra. Based on our earlier modeling of X-ray warm absorbents, we expected to observe X-ray observation in these objects. The third, PLH909, is known to have soft excess in EINSTEIN data. Attachment: "Exploratory ASCA observation of broad absorption line quasi-stellar objects".

  7. Effect of treatment in fractionated schedules with the combination of x-irradiation and six cytotoxic drugs on the RIF-1 tumor and normal mouse skin

    SciTech Connect

    Lelieveld, P.; Scoles, M.A.; Brown, J.M.; Phil, D.; Kallman, R.F.

    1985-01-01

    RIF-1 tumors, implanted syngeneically in the gastrocnemius muscles of the right hind legs of C3H/Km mice, were treated either with X ray alone, drug alone, or drug and X ray combined. The drugs tested were bleomycin, BCNU, cis-diamminedichloro platinum, adriamycin, cyclophosphamide, and actinomycin-D. All drugs were administered either in the maximum tolerated dose or a dose that causes minimal tumor growth delay. Both drugs and X rays were administered either as a single dose or in five daily fractions. In addition to the single modality controls, seven different schedules of combined modalities were tested. Tumors were measured periodically after treatment in order that the day at which each tumor reached 4 times its initial cross-sectional area, i.e., its size at the time of treatment, could be determined. The effect of treatment on tumors was based upon excess growth delay (GD), i.e., T400% (treated)-T400% (untreated control). Treatment effects for the same combined modality schedules were also determined for normal skin, using the early skin reaction as an endpoint. Dose effect factors (DEF) were computed for all combined modality schedules and were based upon calculated radiation dose equivalents. We also calculated supra-additivity ratios, SR/sub I/ and SR/sub II/, therapeutic gain factors and adjusted therapeutic gain factors. The only drugs to produce significant supra-additivity with X rays were cis-Pt and cyclo.

  8. A Dynamic Absorber With Active Vibration Control

    NASA Astrophysics Data System (ADS)

    Huang, S.-J.; Lian, R.-J.

    1994-12-01

    The design and construction of a dynamic absorber incorporating active vibration control is described. The absorber is a two-degrees-of-freedom spring — lumped mass system sliding on a guide pillar, with two internal vibration disturbance sources. Both the main mass and the secondary absorber mass are acted on by DC servo motors, respectively, to suppress the vibration amplitude. The state variable technique is used to model this dynamic system and a decoupling PID control method is used. First, the discrete time state space model is identified by using the commercial software MATLAB. Then the decoupling controller of this multi-input/multi-output system is derived from the identified model. Finally the results of some experiments are presented. The experimental results show that the system is effective in suppressing vibration. Also, the performance of this control strategy for position tracking control is evaluated based on experimental data.

  9. Final report on key comparison CCQM-K55.a (estradiol): An international comparison of mass fraction purity assignment of estradiol

    NASA Astrophysics Data System (ADS)

    Westwood, Steven; Josephs, Ralf; Daireaux, Adeline; Wielgosz, Robert; Davies, Stephen; Wang, Hongjie; Rodrigues, Jainana; Wollinger, Wagner; Windust, Anthony; Kang, Ma; Fuhai, Su; Philipp, Rosemarie; Kuhlich, Paul; Wong, Siu-kay; Shimizu, Yoshitaka; Pérez, Melina; Avila, Marco; Fernandes-Whaley, Maria; Prevoo, D.; de Vos, J.; Visser, R.; Archer, M.; LeGoff, Thierry; Wood, Steve; Bearden, Dan; Bedner, Mary; Boroujerdi, Arezue; Duewer, David; Hancock, Diane; Lang, Brian; Porter, Barbara; Schantz, Michele; Sieber, John; White, Edward; Wise, Stephen A.

    2012-01-01

    Under the auspices of the Organic Analysis Working Group (OAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) a key comparison, CCQM K55.a, was coordinated by the Bureau International des Poids et Mesures (BIPM) in 2009/2010. Eleven national measurement institutes and the BIPM participated. Participants were required to assign the mass fraction of estradiol present as the main component in the comparison sample (CCQM-K55.a) which consisted of a bulk estradiol hemihydrate material obtained from a commercial supplier that had been extensively but not exhaustively dried prior to sub-division into the units supplied for the comparison. Estradiol was selected to be representative of the performance of a laboratory's measurement capability for the purity assignment of organic compounds of medium structural complexity [molar mass range 300-500 Da] and low polarity (pKOW < -2) for which related structure impurities can be quantified by capillary gas phase chromatography (GC) or by high performance liquid chromatography (LC). The majority of participants used a mass balance approach to determine the estradiol content. The key comparison reference value (KCRV) for estradiol in CCQM-K55.a was assigned by combination of KCRVs assigned by consensus from participant results for each orthogonal impurity class. This allowed participants to demonstrate the efficacy (or otherwise) of their implementation of the mass balance approach and to demonstrate that their assigned value for the main component agreed with the KCRV through use of internally consistent contributing methods. The KCRV for the estradiol content of the material was 984.3 mg/g with a combined standard uncertainty of 0.42 mg/g. The individual participant results showed that a relative expanded uncertainty for the purity assignment of 0.2% is a reasonable estimate of the best achievable result by an individual laboratory for a material of this complexity available in this amount at this level of

  10. Absorber for terahertz radiation management

    DOEpatents

    Biallas, George Herman; Apeldoorn, Cornelis; Williams, Gwyn P.; Benson, Stephen V.; Shinn, Michelle D.; Heckman, John D.

    2015-12-08

    A method and apparatus for minimizing the degradation of power in a free electron laser (FEL) generating terahertz (THz) radiation. The method includes inserting an absorber ring in the FEL beam path for absorbing any irregular THz radiation and thus minimizes the degradation of downstream optics and the resulting degradation of the FEL output power. The absorber ring includes an upstream side, a downstream side, and a plurality of wedges spaced radially around the absorber ring. The wedges form a scallop-like feature on the innermost edges of the absorber ring that acts as an apodizer, stopping diffractive focusing of the THz radiation that is not intercepted by the absorber. Spacing between the scallop-like features and the shape of the features approximates the Bartlett apodization function. The absorber ring provides a smooth intensity distribution, rather than one that is peaked on-center, thereby eliminating minor distortion downstream of the absorber.

  11. First result from the Alpha Magnetic Spectrometer on the International Space Station: precision measurement of the positron fraction in primary cosmic rays of 0.5-350 GeV.

    PubMed

    Aguilar, M; Alberti, G; Alpat, B; Alvino, A; Ambrosi, G; Andeen, K; Anderhub, H; Arruda, L; Azzarello, P; Bachlechner, A; Barao, F; Baret, B; Barrau, A; Barrin, L; Bartoloni, A; Basara, L; Basili, A; Batalha, L; Bates, J; Battiston, R; Bazo, J; Becker, R; Becker, U; Behlmann, M; Beischer, B; Berdugo, J; Berges, P; Bertucci, B; Bigongiari, G; Biland, A; Bindi, V; Bizzaglia, S; Boella, G; de Boer, W; Bollweg, K; Bolmont, J; Borgia, B; Borsini, S; Boschini, M J; Boudoul, G; Bourquin, M; Brun, P; Buénerd, M; Burger, J; Burger, W; Cadoux, F; Cai, X D; Capell, M; Casadei, D; Casaus, J; Cascioli, V; Castellini, G; Cernuda, I; Cervelli, F; Chae, M J; Chang, Y H; Chen, A I; Chen, C R; Chen, H; Cheng, G M; Chen, H S; Cheng, L; Chernoplyiokov, N; Chikanian, A; Choumilov, E; Choutko, V; Chung, C H; Clark, C; Clavero, R; Coignet, G; Commichau, V; Consolandi, C; Contin, A; Corti, C; Costado Dios, M T; Coste, B; Crespo, D; Cui, Z; Dai, M; Delgado, C; Della Torre, S; Demirkoz, B; Dennett, P; Derome, L; Di Falco, S; Diao, X H; Diago, A; Djambazov, L; Díaz, C; von Doetinchem, P; Du, W J; Dubois, J M; Duperay, R; Duranti, M; D'Urso, D; Egorov, A; Eline, A; Eppling, F J; Eronen, T; van Es, J; Esser, H; Falvard, A; Fiandrini, E; Fiasson, A; Finch, E; Fisher, P; Flood, K; Foglio, R; Fohey, M; Fopp, S; Fouque, N; Galaktionov, Y; Gallilee, M; Gallin-Martel, L; Gallucci, G; García, B; García, J; García-López, R; García-Tabares, L; Gargiulo, C; Gast, H; Gebauer, I; Gentile, S; Gervasi, M; Gillard, W; Giovacchini, F; Girard, L; Goglov, P; Gong, J; Goy-Henningsen, C; Grandi, D; Graziani, M; Grechko, A; Gross, A; Guerri, I; de la Guía, C; Guo, K H; Habiby, M; Haino, S; Hauler, F; He, Z H; Heil, M; Heilig, J; Hermel, R; Hofer, H; Huang, Z C; Hungerford, W; Incagli, M; Ionica, M; Jacholkowska, A; Jang, W Y; Jinchi, H; Jongmanns, M; Journet, L; Jungermann, L; Karpinski, W; Kim, G N; Kim, K S; Kirn, Th; Kossakowski, R; Koulemzine, A; Kounina, O; Kounine, A; Koutsenko, V; Krafczyk, M S; Laudi, E; Laurenti, G; Lauritzen, C; Lebedev, A; Lee, M W; Lee, S C; Leluc, C; León Vargas, H; Lepareur, V; Li, J Q; Li, Q; Li, T X; Li, W; Li, Z H; Lipari, P; Lin, C H; Liu, D; Liu, H; Lomtadze, T; Lu, Y S; Lucidi, S; Lübelsmeyer, K; Luo, J Z; Lustermann, W; Lv, S; Madsen, J; Majka, R; Malinin, A; Mañá, C; Marín, J; Martin, T; Martínez, G; Masciocchi, F; Masi, N; Maurin, D; McInturff, A; McIntyre, P; Menchaca-Rocha, A; Meng, Q; Menichelli, M; Mereu, I; Millinger, M; Mo, D C; Molina, M; Mott, P; Mujunen, A; Natale, S; Nemeth, P; Ni, J Q; Nikonov, N; Nozzoli, F; Nunes, P; Obermeier, A; Oh, S; Oliva, A; Palmonari, F; Palomares, C; Paniccia, M; Papi, A; Park, W H; Pauluzzi, M; Pauss, F; Pauw, A; Pedreschi, E; Pensotti, S; Pereira, R; Perrin, E; Pessina, G; Pierschel, G; Pilo, F; Piluso, A; Pizzolotto, C; Plyaskin, V; Pochon, J; Pohl, M; Poireau, V; Porter, S; Pouxe, J; Putze, A; Quadrani, L; Qi, X N; Rancoita, P G; Rapin, D; Ren, Z L; Ricol, J S; Riihonen, E; Rodríguez, I; Roeser, U; Rosier-Lees, S; Rossi, L; Rozhkov, A; Rozza, D; Sabellek, A; Sagdeev, R; Sandweiss, J; Santos, B; Saouter, P; Sarchioni, M; Schael, S; Schinzel, D; Schmanau, M; Schwering, G; Schulz von Dratzig, A; Scolieri, G; Seo, E S; Shan, B S; Shi, J Y; Shi, Y M; Siedenburg, T; Siedling, R; Son, D; Spada, F; Spinella, F; Steuer, M; Stiff, K; Sun, W; Sun, W H; Sun, X H; Tacconi, M; Tang, C P; Tang, X W; Tang, Z C; Tao, L; Tassan-Viol, J; Ting, Samuel C C; Ting, S M; Titus, C; Tomassetti, N; Toral, F; Torsti, J; Tsai, J R; Tutt, J C; Ulbricht, J; Urban, T; Vagelli, V; Valente, E; Vannini, C; Valtonen, E; Vargas Trevino, M; Vaurynovich, S; Vecchi, M; Vergain, M; Verlaat, B; Vescovi, C; Vialle, J P; Viertel, G; Volpini, G; Wang, D; Wang, N H; Wang, Q L; Wang, R S; Wang, X; Wang, Z X; Wallraff, W; Weng, Z L; Willenbrock, M; Wlochal, M; Wu, H; Wu, K Y; Wu, Z S; Xiao, W J; Xie, S; Xiong, R Q; Xin, G M; Xu, N S; Xu, W; Yan, Q; Yang, J; Yang, M; Ye, Q H; Yi, H; Yu, Y J; Yu, Z Q; Zeissler, S; Zhang, J G; Zhang, Z; Zhang, M M; Zheng, Z M; Zhuang, H L; Zhukov, V; Zichichi, A; Zuccon, P; Zurbach, C

    2013-04-01

    A precision measurement by the Alpha Magnetic Spectrometer on the International Space Station of the positron fraction in primary cosmic rays in the energy range from 0.5 to 350 GeV based on 6.8 × 10(6) positron and electron events is presented. The very accurate data show that the positron fraction is steadily increasing from 10 to ∼ 250  GeV, but, from 20 to 250 GeV, the slope decreases by an order of magnitude. The positron fraction spectrum shows no fine structure, and the positron to electron ratio shows no observable anisotropy. Together, these features show the existence of new physical phenomena. PMID:25166975

  12. Corrosion resistant neutron absorbing coatings

    SciTech Connect

    Choi, Jor-Shan; Farmer, Joseph C.; Lee, Chuck K.; Walker, Jeffrey; Russell, Paige; Kirkwood, Jon; Yang, Nancy; Champagne, Victor

    2012-05-29

    A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

  13. Corrosion resistant neutron absorbing coatings

    SciTech Connect

    Choi, Jor-Shan; Farmer, Joseph C; Lee, Chuck K; Walker, Jeffrey; Russell, Paige; Kirkwood, Jon; Yang, Nancy; Champagne, Victor

    2013-11-12

    A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

  14. Optically absorbing nanoparticle mediated cell membrane permeabilization.

    PubMed

    Bhattacharyya, Kiran; Mehta, Smit; Viator, John

    2012-11-01

    Membrane permeabilization is imperative for gene and drug delivery systems, along with other cell manipulation methods, since the average eukaryotic cell membrane is not permeable to polar and large nonpolar molecules. Antibody conjugated optically absorbing gold nanospheres are targeted to the cell membrane of T47D breast cancer cell line and irradiated with 5 ns pulse, 20 Hz, 532 nm light to increase membrane permeability. Up to 90% permeabilization with less than 6% death is reported at radiant exposures up to 10 times lower than those of other comparable studies. PMID:23114334

  15. Diffusion Tensor Magnetic Resonance Imaging Finding of Discrepant Fractional Anisotropy Between the Frontal and Parietal Lobes After Whole-Brain Irradiation in Childhood Medulloblastoma Survivors: Reflection of Regional White Matter Radiosensitivity?

    SciTech Connect

    Qiu Deqiang; Kwong, Dora; Chan, Godfrey; Leung, Lucullus; Khong, P.-L.

    2007-11-01

    Purpose: To test the hypothesis that fractional anisotropy (FA) is more severely reduced in white matter of the frontal lobe compared with the parietal lobe after receiving the same whole-brain irradiation dose in a cohort of childhood medulloblastoma survivors. Methods and Materials: Twenty-two medulloblastoma survivors (15 male, mean [{+-} SD] age = 12.1 {+-} 4.6 years) and the same number of control subjects (15 male, aged 12.0 {+-} 4.2 years) were recruited for diffusion tensor magnetic resonance imaging scans. Using an automated tissue classification method and the Talairach Daemon atlas, FA values of frontal and parietal lobes receiving the same radiation dose, and the ratio between them were quantified and denoted as FFA, PFA, and FA{sub f/p}, respectively. The Mann-Whitney U test was used to test for significant differences of FFA, PFA, and FA{sub f/p} between medulloblastoma survivors and control subjects. Results: Frontal lobe and parietal lobe white matter FA were found to be significantly less in medulloblastoma survivors compared with control subjects (frontal p = 0.001, parietal p = 0.026). Moreover, these differences were found to be discrepant, with the frontal lobe having a significantly larger difference in FA compared with the parietal lobe. The FA{sub f/p} of control and medulloblastoma survivors was 1.110 and 1.082, respectively (p = 0.029). Conclusion: Discrepant FA changes after the same irradiation dose suggest radiosensitivity of the frontal lobe white matter compared with the parietal lobe. Special efforts to address the potentially vulnerable frontal lobe after treatment with whole-brain radiation may be needed so as to balance disease control and treatment-related morbidity.

  16. Solar radiation absorbing material

    DOEpatents

    Googin, John M.; Schmitt, Charles R.; Schreyer, James M.; Whitehead, Harlan D.

    1977-01-01

    Solar energy absorbing means in solar collectors are provided by a solar selective carbon surface. A solar selective carbon surface is a microporous carbon surface having pores within the range of 0.2 to 2 micrometers. Such a surface is provided in a microporous carbon article by controlling the pore size. A thermally conductive substrate is provided with a solar selective surface by adhering an array of carbon particles in a suitable binder to the substrate, a majority of said particles having diameters within the range of about 0.2-10 microns.

  17. Absorber for solar power.

    PubMed

    Powell, W R

    1974-10-01

    A simple, economical absorber utilizing a new principle of operation to achieve very low reradiation losses while generating temperatures limited by material properties of quartz is described. Its performance is analyzed and indicates approximately 90% thermal efficiency and 73% conversion efficiency for an earth based unit with moderately concentrated (~tenfold) sunlight incident. It is consequently compatible with the most economic of concentrator mirrors (stamped) or mirrors deployable in space. Space applications are particularly attractive, as temperatures significantly below 300 K are possible and permit even higher conversion efficiency. PMID:20134700

  18. Nitrogen-atom endohedral fullerene synthesis with high efficiency by controlling plasma-ion irradiation energy and C{sub 60} internal energy

    SciTech Connect

    Cho, Soon Cheon; Kaneko, Toshiro Ishida, Hiroyasu; Hatakeyama, Rikizo

    2015-03-28

    The nitrogen-atom endohedral fullerene (N@C{sub 60}) has been synthesized by controlling the plasma ion irradiation energy (E{sub i}) and fullerene (C{sub 60}) behavior in the sublimation phase. We examined the relationship between the synthesis purity of N@C{sub 60} [molar concentration ratio of N@C{sub 60} to pristine fullerene (C{sub 60})] and E{sub i}, which was controlled by changing the substrate bias voltages (V{sub sub}) and gas pressure (P{sub N2}) during the plasma irradiation process. High-density nitrogen-molecular ions (N{sub 2}{sup +}) with a suitable E{sub i} near 80 eV are confirmed to be the optimum condition of the nitrogen plasma for the synthesis of high-purity N@C{sub 60}. In addition, high sublimation of C{sub 60} contributes to a higher yield due to the high internal energy of C{sub 60} and the related cage defects that are present under these conditions. As a result, a purity of 0.83% is realized for the first time, which is almost two orders of magnitude higher than that using other methods.

  19. The AMINO experiment: methane photolysis under Solar VUV irradiation on the EXPOSE-R facility of the International Space Station

    NASA Astrophysics Data System (ADS)

    Carrasco, Nathalie; Cottin, Hervé; Cloix, Mégane; Jérome, Murielle; Bénilan, Yves; Coll, Patrice; Gazeau, Marie-Claire; Raulin, François; Saiagh, Kafila; Chaput, Didier

    2015-01-01

    The scientific aim of the present campaign is to study the whole chain of methane photo-degradation, as initiated by Solar vacuum-ultraviolet irradiation in Titan's atmosphere. For this purpose, the AMINO experiment on the EXPOSE-R mission has loaded closed cells for gas-phase photochemistry in space conditions. Two different gas mixtures have been exposed, named Titan 1 and Titan 2, involving both N2-CH4 gas mixtures, without and with CO2, respectively. CO2 is added as a source of reactive oxygen in the cells. The cell contents were analysed thanks to infrared absorption spectroscopy, gas chromatography and mass spectrometry. Methane consumption leads to the formation of saturated hydrocarbons, with no detectable influence of CO2. This successful campaign provides a first benchmark for characterizing the whole methane photochemical system in space conditions. A thin film of tholin-like compounds appears to form on the cell walls of the exposed cells.

  20. Measurement of ion species in high current ECR H⁺/D⁺ ion source for IFMIF (International Fusion Materials Irradiation Facility).

    PubMed

    Shinto, K; Senée, F; Ayala, J-M; Bolzon, B; Chauvin, N; Gobin, R; Ichimiya, R; Ihara, A; Ikeda, Y; Kasugai, A; Kitano, T; Kondo, K; Marqueta, A; Okumura, Y; Takahashi, H; Valette, M

    2016-02-01

    Ion species ratio of high current positive hydrogen/deuterium ion beams extracted from an electron-cyclotron-resonance ion source for International Fusion Materials Irradiation Facility accelerator was measured by the Doppler shift Balmer-α line spectroscopy. The proton (H(+)) ratio at the middle of the low energy beam transport reached 80% at the hydrogen ion beam extraction of 100 keV/160 mA and the deuteron (D(+)) ratio reached 75% at the deuterium ion beam extraction of 100 keV/113 mA. It is found that the H(+) ratio measured by the spectroscopy gives lower than that derived from the phase-space diagram measured by an Allison scanner type emittance monitor. The H(+)/D(+) ratio estimated by the emittance monitor was more than 90% at those extraction currents. PMID:26931945

  1. Fractional oscillator.

    PubMed

    Stanislavsky, A A

    2004-11-01

    We consider a fractional oscillator which is a generalization of the conventional linear oscillator in the framework of fractional calculus. It is interpreted as an ensemble average of ordinary harmonic oscillators governed by a stochastic time arrow. The intrinsic absorption of the fractional oscillator results from the full contribution of the harmonic oscillator ensemble: these oscillators differ a little from each other in frequency so that each response is compensated by an antiphase response of another harmonic oscillator. This allows one to draw a parallel in the dispersion analysis for media described by a fractional oscillator and an ensemble of ordinary harmonic oscillators with damping. The features of this analysis are discussed. PMID:15600586

  2. Particle size effect on microwave absorbing of La0.67Ba0.33Mn0.94Ti0.06O3 powders prepared by mechanical alloying with the assistance of ultrasonic irradiation

    NASA Astrophysics Data System (ADS)

    Saptari, Sitti Ahmiatri; Manaf, Azwar; Kurniawan, Budhy

    2016-03-01

    Doped manganites have attracted substantial interest due to their unique chemical and physics properties, which makes it possible to be used for microwave absorbing materials. In this paper we report synthesizes and characterization of La0.67Ba0.33Mn0.94Ti0.06O3 powders prepared by mechanical alloying with the assistance of a high power ultrasonic treatment. After solid state reaction, the presence of single phase was confirmed by X-ray Diffraction (XRD). Refinement results showed that samples are single phase with monoclinic structure. It was found that powder materials derived from mechanical alloying results in large variation in the particle size. A significant improvement was obtained upon subjecting the mechanically milled powder materials to an ultrasonication treatment for a relatively short period of time. As determined by particle size analyzer (PSA), the mean particle size gradually decreased from the original size of 5.02 µm to 0.36 µm. Magnetic properties were characterized by VSM, and hysteresis loops results showed that samples are soft magnetic. It was found that when the mean particle size decreases, saturation was increases and coersitivity was decreases. Microwave absorption properties were investigated in the frequency range of 8-12 GHz using vector network analyzer. An optimal reflection loss of 24.44 dB is reached at 11.4 GHz.

  3. Final report on key comparison CCQM-K55.b (aldrin): An international comparison of mass fraction purity assignment of aldrin

    NASA Astrophysics Data System (ADS)

    Westwood, Steven; Josephs, Ralf; Choteau, Tiphaine; Daireaux, Adeline; Mesquida, Charline; Wielgosz, Robert; Rosso, Adriana; Ruiz de Arechavaleta, Mariana; Davies, Stephen; Wang, Hongjie; Pires do Rego, Eliane Cristina; Marques Rodrigues, Janaína; de Freitas Guimarães, Evelyn; Vinicius Barreto Sousa, Marcus; Monteiro, Tânia Maria; Alves das Neves Valente, Laura; Marques Violante, Fernando Gustavo; Rubim Ribeiro Almeida, Renato; Baptista Quaresma, Maria Cristina; Nogueira, Raquel; Windust, Anthony; Dai, Xinhua; Li, Xiaomin; Zhang, Wei; Li, Ming; Shao, Mingwu; Wei, Chao; Wong, Siu-kay; Cabillic, Julie; Gantois, Fanny; Philipp, Rosemarie; Pfeifer, Dietmar; Hein, Sebastian; Klyk-Seitz, Urszula-Anna; Ishikawa, Keiichiro; Castro, Esther; Gonzalez, Norma; Krylov, Anatoly; Tang Lin, Teo; Tong Kooi, Lee; Fernandes-Whaley, M.; Prévoo, D.; Archer, M.; Visser, R.; Nlhapo, N.; de Vos, B.; Ahn, Seonghee; Pookrod, Preeyaporn; Wiangnon, Kanjana; Sudsiri, Nittaya; Muaksang, Kittiya; Cherdchu, Chainarong; Ceyhan Gören, Ahmet; Bilsel, Mine; LeGoff, Thierry; Bearden, Dan; Bedner, Mary; Duewer, David; Hancock, Diane; Lang, Brian; Lippa, Katrice; Schantz, Michele; Sieber, John

    2012-01-01

    Under the auspices of the Organic Analysis Working Group (OAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) a key comparison, CCQM K55.b, was coordinated by the Bureau International des Poids et Mesures (BIPM) in 2010/2011. Nineteen national measurement institutes and the BIPM participated. Participants were required to assign the mass fraction of aldrin present as the main component in the comparison sample for CCQM-K55.b which consisted of technical grade aldrin obtained from the National Measurement Institute Australia that had been subject to serial recrystallization and drying prior to sub-division into the units supplied for the comparison. Aldrin was selected to be representative of the performance of a laboratory's measurement capability for the purity assignment of organic compounds of medium structural complexity [molar mass range 300 Da to 500 Da] and low polarity (pKOW < -2) for which related structure impurities can be quantified by capillary gas phase chromatography (GC). The key comparison reference value (KCRV) for the aldrin content of the material was 950.8 mg/g with a combined standard uncertainty of 0.85 mg/g. The KCRV was assigned by combination of KCRVs assigned by consensus from participant results for each orthogonal impurity class. The relative expanded uncertainties reported by laboratories having results consistent with the KCRV ranged from 0.3% to 0.6% using a mass balance approach and 0.5% to 1% using a qNMR method. The major analytical challenge posed by the material proved to be the detection and quantification of a significant amount of oligomeric organic material within the sample and most participants relying on a mass balance approach displayed a positive bias relative to the KCRV (overestimation of aldrin content) in excess of 10 mg/g due to not having adequate procedures in place to detect and quantify the non-volatile content—specifically the non-volatile organics content—of the comparison sample. There

  4. Liquid Cryogen Absorber for MICE

    SciTech Connect

    Baynham, D.E.; Bish, P.; Bradshaw, T.W.; Cummings, M.A.; Green,M.A.; Ishimoto, S.; Ivaniouchenkov, I.; Lau, W.; Yang, S.Q.; Zisman, M.S.

    2005-08-20

    The Muon Ionization Cooling Experiment (MICE) will test ionization cooling of muons. In order to have effective ionization cooling, one must use an absorber that is made from a low-z material. The most effective low z materials for ionization cooling are hydrogen, helium, lithium hydride, lithium and beryllium, in that order. In order to measure the effect of material on cooling, several absorber materials must be used. This report describes a liquid-hydrogen absorber that is within a pair of superconducting focusing solenoids. The absorber must also be suitable for use with liquid helium. The following absorber components are discussed in this report; the absorber body, its heat exchanger, the hydrogen system, and the hydrogen safety. Absorber cooling and the thin windows are not discussed here.

  5. Artificial and enhanced humification of soil organic matter using microwave irradiation.

    PubMed

    Kim, Min Chan; Kim, Han S

    2013-04-01

    Microwave (MW) irradiation, a less energy-intensive irradiation technique, was employed to promote the changes in physicochemical properties of soil organic matter (SOM). MW was irradiated to forest soils for 10 min. Then, the physical and chemical properties of the SOM were analyzed with UV absorbance spectroscopy, Fourier transform infrared spectroscopy, elemental analysis, and size exclusion chromatography. Also, the SOM was fractionated into biopolymer, fulvic acid, and humic acid, and each fraction was analyzed quantitatively. These analyses revealed that the SOM became more aromatic and nonpolar, highly condensed, and macromolecular organic substances that possess a higher amount of functional groups found in highly humified substances than the original SOM as a result of the MW irradiation. The humification-like alteration of SOM property was attributable to the thermal cracking and to the radical reaction, particularly when the MW was irradiated along with activated carbon under the aerobic condition. The results of this study suggest that the artificial and enhanced property changes of SOM can be accomplished by MW irradiation on an engineering time scale, which can contribute to the successful soil and groundwater remediation practice. PMID:22895631

  6. Nanostructured light-absorbing crystalline CuIn{sub (1–x)}Ga{sub x}Se{sub 2} thin films grown through high flux, low energy ion irradiation

    SciTech Connect

    Hall, Allen J.; Hebert, Damon; Rockett, Angus A.; Shah, Amish B.; Bettge, Martin

    2013-10-21

    A hybrid effusion/sputtering vacuum system was modified with an inductively coupled plasma (ICP) coil enabling ion assisted physical vapor deposition of CuIn{sub 1−x}Ga{sub x}Se{sub 2} thin films on GaAs single crystals and stainless steel foils. With <80 W rf power to the ICP coil at 620–740 °C, film morphologies were unchanged compared to those grown without the ICP. At low temperature (600–670 °C) and high rf power (80–400 W), a light absorbing nanostructured highly anisotropic platelet morphology was produced with surface planes dominated by (112){sub T} facets. At 80–400 W rf power and 640–740 °C, both interconnected void and small platelet morphologies were observed while at >270 W and above >715 °C nanostructured pillars with large inter-pillar voids were produced. The latter appeared black and exhibited a strong (112){sub T} texture with interpillar twist angles of ±8°. Application of a negative dc bias of 0–50 V to the film during growth was not found to alter the film morphology or stoichiometry. The results are interpreted as resulting from the plasma causing strong etching favoring formation of (112){sub T} planes and preferential nucleation of new grains, balanced against conventional thermal diffusion and normal growth mechanisms at higher temperatures. The absence of effects due to applied substrate bias suggests that physical sputtering or ion bombardment effects were minimal. The nanostructured platelet and pillar films were found to exhibit less than one percent reflectivity at angles up to 75° from the surface normal.

  7. Metamaterial electromagnetic wave absorbers.

    PubMed

    Watts, Claire M; Liu, Xianliang; Padilla, Willie J

    2012-06-19

    The advent of negative index materials has spawned extensive research into metamaterials over the past decade. Metamaterials are attractive not only for their exotic electromagnetic properties, but also their promise for applications. A particular branch-the metamaterial perfect absorber (MPA)-has garnered interest due to the fact that it can achieve unity absorptivity of electromagnetic waves. Since its first experimental demonstration in 2008, the MPA has progressed significantly with designs shown across the electromagnetic spectrum, from microwave to optical. In this Progress Report we give an overview of the field and discuss a selection of examples and related applications. The ability of the MPA to exhibit extreme performance flexibility will be discussed and the theory underlying their operation and limitations will be established. Insight is given into what we can expect from this rapidly expanding field and future challenges will be addressed. PMID:22627995

  8. Absorber coatings' degradation

    SciTech Connect

    Moore, S.W.

    1984-01-01

    This report is intended to document some of the Los Alamos efforts that have been carried out under the Department of Energy (DOE) Active Heating and Cooling Materials Reliability, Maintainability, and Exposure Testing program. Funding for these activities is obtained directly from DOE although they represent a variety of projects and coordination with other agencies. Major limitations to the use of solar energy are the uncertain reliability and lifetimes of solar systems. This program is aimed at determining material operating limitations, durabilities, and failure modes such that materials improvements can be made and lifetimes can be extended. Although many active and passive materials and systems are being studied at Los Alamos, this paper will concentrate on absorber coatings and degradation of these coatings.

  9. XIIth international meeting on radiation processing Avignon 25-30 March 2001 (Polymer irradiation: past-present and future)

    NASA Astrophysics Data System (ADS)

    Chapiro, Adolphe

    2002-03-01

    Radiations are used efficiently and economically for the production of new or modified polymers. The following processes are considered: Radiation curing; Radiation cross-linking; Radiation grafting. These processes are commonly used today in industry and provide a broad range of new potential applications in various fields. The history of their development is briefly reported. The chemical reactions underlying these processes are described. (1) Radiation curing is used commercially on a large scale for the production of improved coatings, lacquers and inks. The process can be conducted at very high speeds. Curing of magnetic formulations leads to particularly stable products, which compete favourably with more conventional materials. (2) Radiation cross-linking is an established technology in the wire and cable industry. It emparts to the modified insulators improved resistance to solvents, to ageing and to elevated temperatures. The resulting cross-linked network also reduces the migration of fillers and thereby stabilizes in time any message imprinted with magnetic or colored pigments dispersed in a polymer. (3) Radiation grafting is a powerful method for modifying more profoundly the properties of a polymer and for creating numerous, entirely new materials. The chemical modification can be applied at will into the bulk of the material or limited to a surface zone of any desired depth. This method can be used for instance, for introducing polar groups in the bulk or on the surface of non-polar polymers, for increasing or reducing the wettability of a polymer, for imparting a better compatibility of a polymer to a specific coating and the like. The irradiation of water-soluble polymers in aqueous solutions, with or without the addition of another monomer gives rise to a variety of cross-linked gels which find useful applications in the biomedical field. Other promising applications will be considered.

  10. Characterization of low molecular weight fragments from gamma irradiated κ-carrageenan used as plant growth promoter

    NASA Astrophysics Data System (ADS)

    Abad, Lucille V.; Aurigue, Fernando B.; Relleve, Lorna S.; Montefalcon, Djowel Recto V.; Lopez, Girlie Eunice P.

    2016-01-01

    Radiation degraded κ-carrageenan (1% solution at absorbed doses of 20 kGy and 30 kGy) were tested for its plant growth promoter (PGP) effect on pechay plants under hydroponics condition. Results revealed that higher PGP effects were found in κ-carrageenan irradiated at an absorbed dose of 30 kGy. Mw of irradiated κ-carrageenan as measured by GPC were determined to be 7362 Da and 6762 Da for 20 kGy and 30 kGy, respectively. Fractionation of the irradiated κ-carrageenan (30 kGy) was done to separate different Mw fractions using Mw cut-off filters of 1 kDa, 3 kDa, and 5 kDa. The PGP effect of the different retentates showed that biological activity in plants followed the order of 5 kDa>3 kDa>1 kDa using hydroponics condition but the reverse was observed in the order of 1 kDa>3 kDa>5 kDa when absorbed in plants by foliar spraying. GPC chromatogram indicated at least three (3) low molecular weight (LMW) fragments from radiation modified κ-carrageenan solution with an Mw<2000 Da. A fragment has also been identified with an Mw of as low as 160 Da which was produced under acidic (un-neutralized) condition. This may be attributed to the formation of 5-hydroxymethylfurfural (5-HMF).

  11. Electrochemically regenerable carbon dioxide absorber

    NASA Technical Reports Server (NTRS)

    Woods, R. R.; Marshall, R. D.; Schubert, F. H.; Heppner, D. B.

    1979-01-01

    Preliminary designs were generated for two electrochemically regenerable carbon dioxide absorber concepts. Initially, an electrochemically regenerable absorption bed concept was designed. This concept incorporated the required electrochemical regeneration components in the absorber design, permitting the absorbent to be regenerated within the absorption bed. This hardware was identified as the electrochemical absorber hardware. The second hardware concept separated the functional components of the regeneration and absorption process. This design approach minimized the extravehicular activity component volume by eliminating regeneration hardware components within the absorber. The electrochemical absorber hardware was extensively characterized for major operating parameters such as inlet carbon dioxide partial pressure, process air flow rate, operational pressure, inlet relative humidity, regeneration current density and absorption/regeneration cycle endurance testing.

  12. Liquid Hydrogen Absorber for MICE

    SciTech Connect

    Ishimoto, S.; Suzuki, S.; Yoshida, M.; Green, Michael A.; Kuno, Y.; Lau, Wing

    2010-05-30

    Liquid hydrogen absorbers for the Muon Ionization Cooling Experiment (MICE) have been developed, and the first absorber has been tested at KEK. In the preliminary test at KEK we have successfully filled the absorber with {approx}2 liters of liquid hydrogen. The measured hydrogen condensation speed was 2.5 liters/day at 1.0 bar. No hydrogen leakage to vacuum was found between 300 K and 20 K. The MICE experiment includes three AFC (absorber focusing coil) modules, each containing a 21 liter liquid hydrogen absorber made of aluminum. The AFC module has safety windows to separate its vacuum from that of neighboring modules. Liquid hydrogen is supplied from a cryocooler with cooling power 1.5 W at 4.2 K. The first absorber will be assembled in the AFC module and installed in MICE at RAL.

  13. Broadband patterned magnetic microwave absorber

    SciTech Connect

    Li, Wei; Wu, Tianlong; Wang, Wei; Guan, Jianguo; Zhai, Pengcheng

    2014-07-28

    It is a tough task to greatly improve the working bandwidth for the traditional flat microwave absorbers because of the restriction of available material parameters. In this work, a simple patterning method is proposed to drastically broaden the absorption bandwidth of a conventional magnetic absorber. As a demonstration, an ultra-broadband microwave absorber with more than 90% absorption in the frequency range of 4–40 GHz is designed and experimentally realized, which has a thin thickness of 3.7 mm and a light weight equivalent to a 2-mm-thick flat absorber. In such a patterned absorber, the broadband strong absorption is mainly originated from the simultaneous incorporation of multiple λ/4 resonances and edge diffraction effects. This work provides a facile route to greatly extend the microwave absorption bandwidth for the currently available absorbing materials.

  14. SU-C-210-07: Assessment of Intra-/Inter-Fractional Internal Tumor and Organ Movement in Radiotherapy of Head and Neck Cancer Using On-Board Cine MRI

    SciTech Connect

    Chen, H; Dolly, S; Anastasio, M; Fischer-Valuck, B; Kashani, R; Green, O; Rodriguez, V; Mutic, S; Gay, H; Thorstad, W; Li, H; Victoria, J; Dempsey, J; Ruan, S; Low, D

    2015-06-15

    Purpose: Head and neck (H&N) internal organ motion has previously been determined with low frequency and temporary nature based on population-based pre- and post-treatment studies. Using immobilization masks and adding a 4–6 mm planning-tumor-volume margin, geometric uncertainties of patients are routinely considered clinically inconsequential in H&N radiotherapy. Using the first commercially-available MR-IGRT system, we conducted the first quantitative study on inter-patient, intra- and inter-fractional H&N internal motion patterns to evaluate the necessity of individualized asymmetric internal margins. Methods: Ninety cine sagittal MR image sequences were acquired during the entire treatment course (6–7 weeks) of three H&N cancer patients using the ViewRay™ MR-IGRT system. The images were 5 mm thick and acquired at 4 frames/per second. One of the patients had a tracheostomy tube. The cross-sectional H&N airway (nasopharynx, oropharynx, and laryngopharynx portions) movement was analyzed comprehensively using in-house developed motion detection software. Results: Large inter-patient variations of swallowing frequency (0–1 times/per fraction), swallowing duration (1–3 seconds), and pharyngeal cross-sectional area (238–2516 mm2) were observed. Extensive pharyngeal motion occurred during swallowing, while nonzero and periodic change of airway geometry was observed in resting. For patient 1 with tracheostomy tube replacement, 30.3%, 30.0%, 48.7% and 0.3% of total frames showed ≥ 4 mm displacements in the anterior, posterior, inferior, and superior airway boundaries, respectively; similarly, (5.7%, 0.0%, 0.0%, 0.3%) and (23.3%, 0.0%, 35.7%, 1.7%) occurred for patients 2 and 3. Area overlapping coefficients with respect to the first frame were 76.3+/−6.4%, 90.3+/−0.6%, and 92.3+/−1.2% for the three patients, respectively. Conclusion: Both the resting and swallowing motions varied in frequency and amplitude among the patients and across fractions of a

  15. Plants absorb heavy metals

    SciTech Connect

    Parry, J.

    1995-02-01

    Decontamination of heavy metals-polluted soils remains one of the most intractable problems of cleanup technology. Currently available techniques include extraction of the metals by physical and chemical means, such as acid leaching and electroosmosis, or immobilization by vitrification. There are presently no techniques for cleanup which are low cost and retain soil fertility after metals removal. But a solution to the problem could be on the horizon. A small but growing number of plants native to metalliferous soils are known to be capable of accumulating extremely high concentrations of metals in their aboveground portions. These hyperaccumulators, as they are called, contain up to 1,000 times larger metal concentrations in their aboveground parts than normal species. Their distribution is global, including many different families of flowering plants of varying growth forms, from herbaceous plants to trees. Hyperaccumulators absorb metals they do not need for their own nutrition. The metals are accumulated in the leaf and stem vacuoles, and to a lesser extent in the roots.

  16. Intracellular Cadmium Isotope Fractionation

    NASA Astrophysics Data System (ADS)

    Horner, T. J.; Lee, R. B.; Henderson, G. M.; Rickaby, R. E.

    2011-12-01

    Recent stable isotope studies into the biological utilization of transition metals (e.g. Cu, Fe, Zn, Cd) suggest several stepwise cellular processes can fractionate isotopes in both culture and nature. However, the determination of fractionation factors is often unsatisfactory, as significant variability can exist - even between different organisms with the same cellular functions. Thus, it has not been possible to adequately understand the source and mechanisms of metal isotopic fractionation. In order to address this problem, we investigated the biological fractionation of Cd isotopes within genetically-modified bacteria (E. coli). There is currently only one known biological use or requirement of Cd, a Cd/Zn carbonic anhydrase (CdCA, from the marine diatom T. weissfloggii), which we introduce into the E. coli genome. We have also developed a cleaning procedure that allows for the treating of bacteria so as to study the isotopic composition of different cellular components. We find that whole cells always exhibit a preference for uptake of the lighter isotopes of Cd. Notably, whole cells appear to have a similar Cd isotopic composition regardless of the expression of CdCA within the E. coli. However, isotopic fractionation can occur within the genetically modified E. coli during Cd use, such that Cd bound in CdCA can display a distinct isotopic composition compared to the cell as a whole. Thus, the externally observed fractionation is independent of the internal uses of Cd, with the largest Cd isotope fractionation occurring during cross-membrane transport. A general implication of these experiments is that trace metal isotopic fractionation most likely reflects metal transport into biological cells (either actively or passively), rather than relating to expression of specific physiological function and genetic expression of different metalloenzymes.

  17. Fraction Reduction through Continued Fractions

    ERIC Educational Resources Information Center

    Carley, Holly

    2011-01-01

    This article presents a method of reducing fractions without factoring. The ideas presented may be useful as a project for motivated students in an undergraduate number theory course. The discussion is related to the Euclidean Algorithm and its variations may lead to projects or early examples involving efficiency of an algorithm.

  18. What is the best microwave absorber?

    SciTech Connect

    Hutcheon, R.M.; Adams, F.P.; De Jong, M.S.

    1995-12-31

    The absorption of microwave power by samples with different shapes and dielectric properties was studied for single-mode excitation of a microwave applicator. Exact calculations were done of the quality factor, Q and the frequency shift of a cylindrically-symmetric cavity with a small, cylindrically-symmetric sample on-axis in the cavity, demonstrating the influence of sample shape and dielectric properties on the power absorption per unit volume of the sample. An approximate, but very general, analytical formalism was developed for calculating the power absorbed by the sample and thus the contribution of the sample to the Q of the cavity. This simple formalism is shown, by comparison with the exact calculations, to be quite accurate over a very broad range of properties. Thus, it can be used to calculate the power absorbed by samples which are smaller than the internal wavelength, and also to gain insight into the factors that influence the microwave absorption.

  19. Pulsed photothermal radiometry in optically transparent media containing discrete optical absorbers.

    PubMed

    Vitkin, I A; Wilson, B C; Anderson, R R; Prahl, S A

    1994-10-01

    A description of heat transport by conduction and radiation in inhomogeneous materials following absorption of a brief optical pulse is presented, and investigated experimentally using pulsed photothermal radiometry (PPTR). The model indicates that the role of radiation as an intramedium heat transfer modality increases with increasing temperatures and decreasing infrared (IR) absorption of the medium. However, for the range of conditions analysed in this study, conductive transfer dominates. Thus, the inclusion of radiation does not significantly perturb the internal temperature profiles, although it does influence the radiometric emission from the sample, and hence the PPTR signal. The thermal confinement effects described in this study may be relevant in photomedicine, for example in pulsed laser irradiation of tissues containing small absorbing targets. PMID:15551541

  20. Energy absorber for the CETA

    NASA Astrophysics Data System (ADS)

    Wesselski, Clarence J.

    1994-05-01

    The energy absorber that was developed for the CETA (Crew Equipment and Translation Aid) on Space Station Freedom is a metal on metal frictional type and has a load regulating feature that prevents excessive stroking loads from occurring while in operation. This paper highlights some of the design and operating aspects and the testing of this energy absorber.

  1. Energy absorber for the CETA

    NASA Technical Reports Server (NTRS)

    Wesselski, Clarence J.

    1994-01-01

    The energy absorber that was developed for the CETA (Crew Equipment and Translation Aid) on Space Station Freedom is a metal on metal frictional type and has a load regulating feature that prevents excessive stroking loads from occurring while in operation. This paper highlights some of the design and operating aspects and the testing of this energy absorber.

  2. Metal-shearing energy absorber

    NASA Technical Reports Server (NTRS)

    Fay, R. J.; Wittrock, E. P.

    1971-01-01

    Device, consisting of tongue of thin aluminum alloy strip, pull tab, slotted steel plate which serves as cutter, and steel buckle, absorbs mechanical energy when its ends are subjected to tensile loading. Device is applicable as auxiliary shock absorbing anchor for automobile and airplane safety belts.

  3. Uncertainties of organ-absorbed doses to patients from 18f-choline

    NASA Astrophysics Data System (ADS)

    Li, W. B.; Janzen, T.; Zankl, M.; Giussani, A.; Hoeschen, C.

    2011-03-01

    Radiation doses of radiopharmaceuticals to patients in nuclear medicine are, as the standard method, estimated by the administered activity, medical imaging (e.g. PET imaging), compartmental modeling and Monte Carlo simulation of radiation with reference digital human phantoms. However, in each of the contributing terms, individual uncertainty due to measurement techniques, patient variability and computation methods may propagate to the uncertainties of the calculated organ doses to the individual patient. To evaluate the overall uncertainties and the quality assurance of internal absorbed doses, a method was developed within the framework of the MADEIRA Project (Minimizing Activity and Dose with Enhanced Image quality by Radiopharmaceutical Administrations) to quantitatively analyze the uncertainties in each component of the organ absorbed doses after administration of 18F-choline to prostate cancer patients undergoing nuclear medicine diagnostics. First, on the basis of the organ PET and CT images of the patients as well as blood and urine samples, a model structure of 18F-choline was developed and the uncertainties of the model parameters were determined. Second, the model parameter values were sampled and biokinetic modeling using these sampled parameter values were performed. Third, the uncertainties of the new specific absorbed fraction (SAF) values derived with different phantoms representing individual patients were presented. Finally, the uncertainties of absorbed doses to the patients were calculated by applying the ICRP/ICRU adult male reference computational phantom. In addition to the uncertainty analysis, the sensitivity of the model parameters on the organ PET images and absorbed doses was indicated by coupling the model input and output using regression and partial correlation analysis. The results showed that the uncertainty factors of absorbed dose to patients are in most cases less than a factor of 2 without taking into account the uncertainties

  4. Visible light broadband perfect absorbers

    NASA Astrophysics Data System (ADS)

    Jia, X. L.; Meng, Q. X.; Yuan, C. X.; Zhou, Z. X.; Wang, X. O.

    2016-03-01

    The visible light broadband perfect absorbers based on the silver (Ag) nano elliptical disks and holes array are studied using finite difference time domain simulations. The semiconducting indium silicon dioxide thin film is introduced as the space layer in this sandwiched structure. Utilizing the asymmetrical geometry of the structures, polarization sensitivity for transverse electric wave (TE)/transverse magnetic wave (TM) and left circular polarization wave (LCP)/right circular polarization wave (RCP) of the broadband absorption are gained. The absorbers with Ag nano disks and holes array show several peaks absorbance of 100% by numerical simulation. These simple and flexible perfect absorbers are particularly desirable for various potential applications including the solar energy absorber.

  5. thin films as absorber

    NASA Astrophysics Data System (ADS)

    González, J. O.; Shaji, S.; Avellaneda, D.; Castillo, G. A.; Das Roy, T. K.; Krishnan, B.

    2014-09-01

    Photovoltaic structures were prepared using AgSb(S x Se1- x )2 as absorber and CdS as window layer at various conditions via a hybrid technique of chemical bath deposition and thermal evaporation followed by heat treatments. Silver antimony sulfo selenide thin films [AgSb(S x Se1- x )2] were prepared by heating multilayers of sequentially deposited Sb2S3/Ag dipped in Na2SeSO3 solution, glass/Sb2S3/Ag/Se. For this, Sb2S3 thin films were deposited from a chemical bath containing SbCl3 and Na2S2O3. Then, Ag thin films were thermally evaporated on glass/Sb2S3, followed by selenization by dipping in an acidic solution of Na2SeSO3. The duration of dipping was varied as 3, 4 and 5 h. Two different heat treatments, one at 350 °C for 20 min in vacuum followed by a post-heat treatment at 325 °C for 2 h in Ar, and the other at 350 °C for 1 h in Ar, were applied to the multilayers of different configurations. X-ray diffraction results showed the formation of AgSb(S x Se1- x )2 thin films as the primary phase and AgSb(S,Se)2 and Sb2S3 as secondary phases. Morphology and elemental detection were done by scanning electron microscopy and energy dispersive X-ray analysis. X-ray photoelectron spectroscopic studies showed the depthwise composition of the films. Optical properties were determined by UV-vis-IR transmittance and reflection spectral analysis. AgSb(S x Se1- x )2 formed at different conditions was incorporated in PV structures glass/FTO/CdS/AgSb(S x Se1- x )2/C/Ag. Chemically deposited post-annealed CdS thin films of various thicknesses were used as window layer. J- V characteristics of the cells were measured under dark and AM1.5 illumination. Analysis of the J- V characteristics resulted in the best solar cell parameters of V oc = 520 mV, J sc = 9.70 mA cm-2, FF = 0.50 and η = 2.7 %.

  6. The changes in optical absorbance of ZrO2 thin film with the rise of the absorbed dose

    NASA Astrophysics Data System (ADS)

    Abayli, D.; Baydogan, N.

    2016-03-01

    In this study, zirconium oxide (ZrO2) thin film samples prepared by sol-gel method were irradiated using Co-60 radioisotope as gamma source. Then, it was investigated the ionizing effect on optical properties of ZrO2 thin film samples with the rise of the absorbed dose. The changes in the optical absorbance of ZrO2 thin films were determined by using optical transmittance and the reflectance measurements in the range between 190 - 1100 nm obtained from PG Instruments T80 UV-Vis spectrophotometer.

  7. UNDERSTANDING TRENDS ASSOCIATED WITH CLOUDS IN IRRADIATED EXOPLANETS

    SciTech Connect

    Heng, Kevin; Demory, Brice-Olivier E-mail: demory@mit.edu

    2013-11-10

    Unlike previously explored relationships between the properties of hot Jovian atmospheres, the geometric albedo and the incident stellar flux do not exhibit a clear correlation, as revealed by our re-analysis of Q0-Q14 Kepler data. If the albedo is primarily associated with the presence of clouds in these irradiated atmospheres, a holistic modeling approach needs to relate the following properties: the strength of stellar irradiation (and hence the strength and depth of atmospheric circulation), the geometric albedo (which controls both the fraction of starlight absorbed and the pressure level at which it is predominantly absorbed), and the properties of the embedded cloud particles (which determine the albedo). The anticipated diversity in cloud properties renders any correlation between the geometric albedo and the stellar flux weak and characterized by considerable scatter. In the limit of vertically uniform populations of scatterers and absorbers, we use an analytical model and scaling relations to relate the temperature-pressure profile of an irradiated atmosphere and the photon deposition layer and to estimate whether a cloud particle will be lofted by atmospheric circulation. We derive an analytical formula for computing the albedo spectrum in terms of the cloud properties, which we compare to the measured albedo spectrum of HD 189733b by Evans et al. Furthermore, we show that whether an optical phase curve is flat or sinusoidal depends on whether the particles are small or large as defined by the Knudsen number. This may be an explanation for why Kepler-7b exhibits evidence for the longitudinal variation in abundance of condensates, while Kepler-12b shows no evidence for the presence of condensates despite the incident stellar flux being similar for both exoplanets. We include an 'observer's cookbook' for deciphering various scenarios associated with the optical phase curve, the peak offset of the infrared phase curve, and the geometric albedo.

  8. Understanding Trends Associated with Clouds in Irradiated Exoplanets

    NASA Astrophysics Data System (ADS)

    Heng, Kevin; Demory, Brice-Olivier

    2013-11-01

    Unlike previously explored relationships between the properties of hot Jovian atmospheres, the geometric albedo and the incident stellar flux do not exhibit a clear correlation, as revealed by our re-analysis of Q0-Q14 Kepler data. If the albedo is primarily associated with the presence of clouds in these irradiated atmospheres, a holistic modeling approach needs to relate the following properties: the strength of stellar irradiation (and hence the strength and depth of atmospheric circulation), the geometric albedo (which controls both the fraction of starlight absorbed and the pressure level at which it is predominantly absorbed), and the properties of the embedded cloud particles (which determine the albedo). The anticipated diversity in cloud properties renders any correlation between the geometric albedo and the stellar flux weak and characterized by considerable scatter. In the limit of vertically uniform populations of scatterers and absorbers, we use an analytical model and scaling relations to relate the temperature-pressure profile of an irradiated atmosphere and the photon deposition layer and to estimate whether a cloud particle will be lofted by atmospheric circulation. We derive an analytical formula for computing the albedo spectrum in terms of the cloud properties, which we compare to the measured albedo spectrum of HD 189733b by Evans et al. Furthermore, we show that whether an optical phase curve is flat or sinusoidal depends on whether the particles are small or large as defined by the Knudsen number. This may be an explanation for why Kepler-7b exhibits evidence for the longitudinal variation in abundance of condensates, while Kepler-12b shows no evidence for the presence of condensates despite the incident stellar flux being similar for both exoplanets. We include an "observer's cookbook" for deciphering various scenarios associated with the optical phase curve, the peak offset of the infrared phase curve, and the geometric albedo.

  9. Absorbent product to absorb fluids. [for collection of human wastes

    NASA Technical Reports Server (NTRS)

    Dawn, F. S.; Correale, J. V. (Inventor)

    1982-01-01

    A multi-layer absorbent product for use in contact with the skin to absorb fluids is discussed. The product utilizes a water pervious facing layer for contacting the skin, overlayed by a first fibrous wicking layer, the wicking layer preferably being of the one-way variety in which fluid or liquid is moved away from the facing layer. The product further includes a first container section defined by inner and outer layer of a water pervious wicking material between which is disposed a first absorbent mass. A second container section defined by inner and outer layers between which is disposed a second absorbent mass and a liquid impermeable/gas permeable layer. Spacesuit applications are discussed.

  10. Self-irradiation of the blood from selected nuclides in nuclear medicine

    NASA Astrophysics Data System (ADS)

    Hänscheid, H.; Fernández, M.; Eberlein, U.; Lassmann, M.

    2014-03-01

    Nuclear medicine dosimetry and research in biodosimetry often require the knowledge of the absorbed dose to the blood. This study provides coefficients for the absorbed dose rates to the blood related to the activity concentration in the blood as a function of the vessel radius for radionuclides commonly used in targeted radiotherapy and in PET-diagnostics: C-11, F-18, Ga-68, Y-90, Tc-99 m, I-124, I-131, and Lu-177. The energy deposition patterns after nuclear disintegrations in blood vessel lumina (cylinders homogeneously filled with blood) with radii from 0.01 to 25.0 mm were simulated with the Monte-Carlo radiation transport code MCNPX. An additional contribution from photon radiation from activity in blood in the remainder of the body was taken into account based on a reasonable blood distribution model. The fraction of energy absorbed from non-penetrating radiation in the blood is low in thin blood vessels but approaches the total energy emitted by particles with increasing lumen radius. For photon radiation, irradiation to blood in small vessels is almost completely due to radioactive decays in distant blood distributed throughout the body, whereas the contribution from activity in the vessel becomes dominant for lumen radii exceeding 13 mm. The dependences of the absorbed dose rates on the lumen radius can be described with good accuracy by empirical functions which can be used to determine the absorbed doses to the blood and to the surrounding tissue.

  11. Evaluation of absorbed dose in Gadolinium neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Abdullaeva, Gayane; Djuraeva, Gulnara; Kim, Andrey; Koblik, Yuriy; Kulabdullaev, Gairatulla; Rakhmonov, Turdimukhammad; Saytjanov, Shavkat

    2015-02-01

    Gadolinium neutron capture therapy (GdNCT) is used for treatment of radioresistant malignant tumors. The absorbed dose in GdNCT can be divided into four primary dose components: thermal neutron, fast neutron, photon and natural gadolinium doses. The most significant is the dose created by natural gadolinium. The amount of gadolinium at the irradiated region is changeable and depends on the gadolinium delivery agent and on the structure of the location where the agent is injected. To de- fine the time dependence of the gadolinium concentration ρ(t) in the irradiated region the pharmacokinetics of gadolinium delivery agent (Magnevist) was studied at intratumoral injection in mice and intramuscular injection in rats. A polynomial approximation was applied to the experimental data and the influence of ρ(t) on the relative change of the absorbed dose of gadolinium was studied.

  12. 1.22 {mu}m GaInNAs Saturable Absorber Mirrors with Tailored Recovery Time

    SciTech Connect

    Puustinen, Janne; Guina, Mircea; Korpijaervi, Ville-Markus; Tukiainen, Antti; Kivistoe, Samuli; Pessa, Markus; Marcinkevicius, Saulius

    2010-11-10

    The effect of in-situ N-ion irradiation on the recombination dynamics of GaInNAs/GaAs semiconductor saturable absorber mirrors has been studied. The samples were fabricated by molecular beam epitaxy using a radio frequency plasma source for nitrogen incorporation in the absorber layers as well as for the irradiation. The recombination dynamics of irradiated samples were studied by pump-probe measurements. The recombination time of the absorbers could be reduced by increasing the irradiation time. The effect of the reduced recombination time on the pulse dynamics of a mode-locked laser setup was studied with a Bi-doped fibre laser. The pulse quality was found to improve with increased irradiation time and reduced recombination time, demonstrating the potential of the in-situ irradiation method for device applications.

  13. Tracking the Partial Covering Absorbers in NGC 2110 with Suzaku: Constraints on Clumpy Absorber Models

    NASA Astrophysics Data System (ADS)

    Rothschild, Richard

    How do matter, energy, space and time behave under the extraordinarily diverse conditions of the cosmos? How did the Universe originate and evolve to produce the galaxies we see today? These are some of the biggest unanswered questions in astronomy today. In our study of Active Galactic Nuclei (AGN) we want to explore these questions and ask more explicitly what is the accretion history of the Universe? How do supermassive black holes acquire material and what happens when it does? To answer this we need to know the physical conditions and geometry of the accreting circumnuclear material in the vicinity of the supermassive black holes in AGN. This is an important piece of the AGN puzzle that we are able to study through detailed X-ray spectroscopic observations of AGN. We herein request support for our analysis of two Suzaku observations of the AGN NGC 2110, an unpublished archival observation from 2005 and an upcoming observation. This type 2 Seyfert AGN shows significant obscuration in the soft X-ray band from a complex of multiple absorbers with different column densities and covering fractions. Studying these partial-covering absorbers can tell us about the material surrounding the central black hole. We can learn how much material there is by through the level of absorption and the location of the accreting gas from the black hole via measurements of the level of ionization. Additionally, covering fractions and particularly time variability of covering fractions can hint at the clumpiness of the medium. Taking advantage of Suzaku s large energy range we can also quantify the Compton reflection hump, a broad spectral feature which peaks around 20 30 keV and is indicative of reflection off Compton-thick material in the vicinity of the central black hole. most likely either the accretion disk itself or a geometrically thick torus of material further out. The nature of this material is still an open question and recent work has been done using infrared

  14. Countercurrent flow absorber and desorber

    DOEpatents

    Wilkinson, William H.

    1984-01-01

    Countercurrent flow absorber and desorber devices are provided for use in absorption cycle refrigeration systems and thermal boosting systems. The devices have increased residence time and surface area resulting in improved heat and mass transfer characteristics. The apparatuses may be incorporated into open cycle thermal boosting systems in which steam serves both as the refrigerant vapor which is supplied to the absorber section and as the supply of heat to drive the desorber section of the system.

  15. Hyperuniformity of critical absorbing states.

    PubMed

    Hexner, Daniel; Levine, Dov

    2015-03-20

    The properties of the absorbing states of nonequilibrium models belonging to the conserved directed percolation universality class are studied. We find that, at the critical point, the absorbing states are hyperuniform, exhibiting anomalously small density fluctuations. The exponent characterizing the fluctuations is measured numerically, a scaling relation to other known exponents is suggested, and a new correlation length relating to this ordering is proposed. These results may have relevance to photonic band-gap materials. PMID:25839254

  16. Hyperuniformity of Critical Absorbing States

    NASA Astrophysics Data System (ADS)

    Hexner, Daniel; Levine, Dov

    2015-03-01

    The properties of the absorbing states of nonequilibrium models belonging to the conserved directed percolation universality class are studied. We find that, at the critical point, the absorbing states are hyperuniform, exhibiting anomalously small density fluctuations. The exponent characterizing the fluctuations is measured numerically, a scaling relation to other known exponents is suggested, and a new correlation length relating to this ordering is proposed. These results may have relevance to photonic band-gap materials.

  17. Packed Alumina Absorbs Hypergolic Vapors

    NASA Technical Reports Server (NTRS)

    Thomas, J. J.; Mauro, D. M.

    1984-01-01

    Beds of activated alumina effective as filters to remove hypergolic vapors from gas streams. Beds absorb such substances as nitrogen oxides and hydrazines and may also absorb acetylene, ethylene, hydrogen sulfide, benzene, butadiene, butene, styrene, toluene, and xoylene. Bed has no moving parts such as pumps, blowers and mixers. Reliable and energy-conservative. Bed readily adapted to any size from small portable units for use where little vapor release is expected to large stationary units for extensive transfer operations.

  18. Countercurrent flow absorber and desorber

    DOEpatents

    Wilkinson, W.H.

    1984-10-16

    Countercurrent flow absorber and desorber devices are provided for use in absorption cycle refrigeration systems and thermal boosting systems. The devices have increased residence time and surface area resulting in improved heat and mass transfer characteristics. The apparatuses may be incorporated into open cycle thermal boosting systems in which steam serves both as the refrigerant vapor which is supplied to the absorber section and as the supply of heat to drive the desorber section of the system. 9 figs.

  19. Incidental irradiation of internal mammary lymph nodes in breast cancer: conventional two-dimensional radiotherapy versus conformal three-dimensional radiotherapy*

    PubMed Central

    Leite, Elton Trigo Teixeira; Ugino, Rafael Tsuneki; Santana, Marco Antônio; Ferreira, Denis Vasconcelos; Lopes, Maurício Russo; Pelosi, Edilson Lopes; da Silva, João Luis Fernandes; Carvalho, Heloisa de Andrade

    2016-01-01

    Objective To evaluate incidental irradiation of the internal mammary lymph nodes (IMLNs) through opposed tangential fields with conventional two-dimensional (2D) or three-dimensional (3D) radiotherapy techniques and to compare the results between the two techniques. Materials and Methods This was a retrospective study of 80 breast cancer patients in whom radiotherapy of the IMLNs was not indicated: 40 underwent 2D radiotherapy with computed tomography for dosimetric control, and 40 underwent 3D radiotherapy. The total prescribed dose was 50.0 Gy or 50.4 Gy (2.0 or 1.8 Gy/day, respectively). We reviewed all plans and defined the IMLNs following the Radiation Therapy Oncology Group recommendations. For the IMLNs, we analyzed the proportion of the volume that received 45 Gy, the proportion of the volume that received 25 Gy, the dose to 95% of the volume, the dose to 50% of the volume, the mean dose, the minimum dose (Dmin), and the maximum dose (Dmax). Results Left-sided treatments predominated in the 3D cohort. There were no differences between the 2D and 3D cohorts regarding tumor stage, type of surgery (mastectomy, breast-conserving surgery, or mastectomy with immediate reconstruction), or mean delineated IMLN volume (6.8 vs. 5.9 mL; p = 0.411). Except for the Dmin, all dosimetric parameters presented higher mean values in the 3D cohort (p < 0.05). The median Dmax in the 3D cohort was 50.34 Gy. However, the mean dose to the IMLNs was 7.93 Gy in the 2D cohort, compared with 20.64 Gy in the 3D cohort. Conclusion Neither technique delivered enough doses to the IMLNs to achieve subclinical disease control. However, all of the dosimetric parameters were significantly higher for the 3D technique. PMID:27403017

  20. EPR Investigation of Irradiated Curry Powder

    SciTech Connect

    Duliu, O. G.; Ali, S. I.; Georgescu, R.

    2007-04-23

    Gamma-ray irradiated curry powder, a well priced oriental spice was investigated in order to establish the ability of EPR to detect the presence and time stability of free irradiation free-radicals. Accordingly, curry powder aliquots were irradiated with gradually increasing absorbed doses up to 11.3 kGy. The EPR spectra of all irradiated samples show the presence of al last two different species of free radicals, whose concentration increased monotonously with the absorbed doses. A 100 deg. C isothermal annealing of irradiated samples has shown a differential reduction of amplitude of various components of the initial spectra, but even after 3.6 h of thermal treatment, the remaining amplitude represents no less then 30% of the initial ones. The same peculiarities have been noticed after more than one year storage at room temperature, all of them being very useful in establishing the existence of any previous irradiation treatment.

  1. A discrete chemo-dynamical model of the giant elliptical galaxy NGC 5846: dark matter fraction, internal rotation and velocity anisotropy out to six effective radii

    NASA Astrophysics Data System (ADS)

    Zhu, Ling; Romanowsky, Aaron J.; van de Ven, Glenn; Long, R. J.; Watkins, Laura L.; Pota, Vincenzo; Napolitano, Nicola R.; Forbes, Duncan A.; Brodie, Jean; Foster, Caroline

    2016-08-01

    We construct a suite of discrete chemo-dynamical models of the giant elliptical galaxy NGC 5846. These models are a powerful tool to constrain both the mass distribution and internal dynamics of multiple tracer populations. We use Jeans models to simultaneously fit stellar kinematics within the effective radius Re, planetary nebula (PN) radial velocities out to 3 Re, and globular cluster (GC) radial velocities and colours out to 6 Re. The best-fitting model is a cored DM halo which contributes ˜10% of the total mass within 1 Re, and 67% ± 10% within 6 Re, although a cusped DM halo is also acceptable. The red GCs exhibit mild rotation with vmax/σ0 ˜ 0.3 in the region R > Re, aligned with but counter-rotating to the stars in the inner parts, while the blue GCs and PNe kinematics are consistent with no rotation. The red GCs are tangentially anisotropic, the blue GCs are mildly radially anisotropic, and the PNe vary from radially to tangentially anisotropic from the inner to the outer region. This is confirmed by general made-to-measure models. The tangential anisotropy of the red GCs in the inner regions could stem from the preferential destruction of red GCs on more radial orbits, while their outer tangential anisotropy - similar to the PNe in this region - has no good explanation. The mild radial anisotropy of the blue GCs is consistent with an accretion scenario.

  2. [Analysis of the importance of cosmonaut's location and orientation onboard the International space station to levels of visceral irradiation during traverse of the region of the South Atlantic Anomaly].

    PubMed

    Drobyshev, S G; Benghin, V V

    2015-01-01

    Parametric analysis of absorbed radiation dose to the cosmonaut working in the Service module (SM) of the International space station (ISS) was made with allowance for anisotropy of the radiation field of the South Atlantic Anomaly. Calculation data show that in weakly shielded SM compartments the radiation dose to poorly shielded viscera may depend essentially on cosmonaut's location and orientation relative to the ISS shell. Difference of the lens absorbed dose can be as high as 5 times depending on orientation of the cosmonaut and the ISS. The effect is less pronounced on the deep seated hematopoietic system; however, it may increase up to 2.5 times during the extravehicular activities. When the cosmonaut is outside on the ISS SM side presented eastward, the absorbed dose can be affected noticeably by remoteness from the SM. At a distance less than 1.5 meters away from the SM east side in the course of ascending circuits, the calculated lens dose is approximately half as compared with the situation when the cosmonaut is not shielded by the ISS material. PMID:25958468

  3. Direct MC conversion of absorbed dose to graphite to absorbed dose to water for 60Co radiation.

    PubMed

    Lye, J E; Butler, D J; Franich, R D; Harty, P D; Oliver, C P; Ramanathan, G; Webb, D V; Wright, T

    2013-06-01

    The ARPANSA calibration service for (60)Co gamma rays is based on a primary standard graphite calorimeter that measures absorbed dose to graphite. Measurements with the calorimeter are converted to the absorbed dose to water using the calculation of the ratio of the absorbed dose in the calorimeter to the absorbed dose in a water phantom. ARPANSA has recently changed the basis of this calculation from a photon fluence scaling method to a direct Monte Carlo (MC) calculation. The MC conversion uses an EGSnrc model of the cobalt source that has been validated against water tank and graphite phantom measurements, a step that is required to quantify uncertainties in the underlying interaction coefficients in the MC code. A comparison with the Bureau International des Poids et Mesures (BIPM) as part of the key comparison BIPM.RI(I)-K4 showed an agreement of 0.9973 (53). PMID:23152147

  4. Carbon Absorber Retrofit Equipment (CARE)

    SciTech Connect

    Klein, Eric

    2015-12-23

    During Project DE-FE0007528, CARE (Carbon Absorber Retrofit Equipment), Neumann Systems Group (NSG) designed, installed and tested a 0.5MW NeuStream® carbon dioxide (CO2) capture system using the patented NeuStream® absorber equipment and concentrated (6 molal) piperazine (PZ) as the solvent at Colorado Springs Utilities’ (CSU’s) Martin Drake pulverized coal (PC) power plant. The 36 month project included design, build and test phases. The 0.5MW NeuStream® CO2 capture system was successfully tested on flue gas from both coal and natural gas combustion sources and was shown to meet project objectives. Ninety percent CO2 removal was achieved with greater than 95% CO2product purity. The absorbers tested support a 90% reduction in absorber volume compared to packed towers and with an absorber parasitic power of less than 1% when configured for operation with a 550MW coal plant. The preliminary techno-economic analysis (TEA) performed by the Energy and Environmental Research Center (EERC) predicted an over-the-fence cost of $25.73/tonne of CO2 captured from a sub-critical PC plant.

  5. Mushroom plasmonic metamaterial infrared absorbers

    NASA Astrophysics Data System (ADS)

    Ogawa, Shinpei; Fujisawa, Daisuke; Hata, Hisatoshi; Uetsuki, Mitsuharu; Misaki, Koji; Kimata, Masafumi

    2015-01-01

    There has been a considerable amount of interest in the development of various types of electromagnetic wave absorbers for use in different wavelength ranges. In particular, infrared (IR) absorbers with wavelength selectivity can be applied to advanced uncooled IR sensors, which would be capable of identifying objects through their radiation spectrum. In the present study, mushroom plasmonic metamaterial absorbers (MPMAs) for the IR wavelength region were designed and fabricated. The MPMAs consist of a periodic array of thin metal micropatches connected to a thin metal plate with narrow silicon (Si) posts. A Si post height of 200 nm was achieved by isotropic XeF2 etching of a thin Si layer sandwiched between metal plates. This fabrication procedure is relatively simple and is consistent with complementary metal oxide semiconductor technology. The absorption spectra of the fabricated MPMAs were experimentally measured. In addition, theoretical calculations of their absorption properties were conducted using rigorous coupled wave analysis. Both the calculated and measured absorbance results demonstrated that these MPMAs can realize strong selective absorption at wavelengths beyond the period of the array by varying the micropatch width. Absorbance values greater than 90% were achieved. Dual- or single-mode absorption can also be selected by varying the width of the Si posts. Pixel structures using such MPMAs could be used as high responsivity, high resolution and fast uncooled IR sensors.

  6. Additive manufacturing of RF absorbers

    NASA Astrophysics Data System (ADS)

    Mills, Matthew S.

    The ability of additive manufacturing techniques to fabricate integrated electromagnetic absorbers tuned for specific radio frequency bands within structural composites allows for unique combinations of mechanical and electromagnetic properties. These composites and films can be used for RF shielding of sensitive electromagnetic components through in-plane and out-of-plane RF absorption. Structural composites are a common building block of many commercial platforms. These platforms may be placed in situations in which there is a need for embedded RF absorbing properties along with structural properties. Instead of adding radar absorbing treatments to the external surface of existing structures, which adds increased size, weight and cost; it could prove to be advantageous to integrate the microwave absorbing properties directly into the composite during the fabrication process. In this thesis, a method based on additive manufacturing techniques of composites structures with prescribed electromagnetic loss, within the frequency range 1 to 26GHz, is presented. This method utilizes screen printing and nScrypt micro dispensing to pattern a carbon based ink onto low loss substrates. The materials chosen for this study will be presented, and the fabrication technique that these materials went through to create RF absorbing structures will be described. The calibration methods used, the modeling of the RF structures, and the applications in which this technology can be utilized will also be presented.

  7. Mushroom plasmonic metamaterial infrared absorbers

    SciTech Connect

    Ogawa, Shinpei Fujisawa, Daisuke; Hata, Hisatoshi; Uetsuki, Mitsuharu; Misaki, Koji; Kimata, Masafumi

    2015-01-26

    There has been a considerable amount of interest in the development of various types of electromagnetic wave absorbers for use in different wavelength ranges. In particular, infrared (IR) absorbers with wavelength selectivity can be applied to advanced uncooled IR sensors, which would be capable of identifying objects through their radiation spectrum. In the present study, mushroom plasmonic metamaterial absorbers (MPMAs) for the IR wavelength region were designed and fabricated. The MPMAs consist of a periodic array of thin metal micropatches connected to a thin metal plate with narrow silicon (Si) posts. A Si post height of 200 nm was achieved by isotropic XeF{sub 2} etching of a thin Si layer sandwiched between metal plates. This fabrication procedure is relatively simple and is consistent with complementary metal oxide semiconductor technology. The absorption spectra of the fabricated MPMAs were experimentally measured. In addition, theoretical calculations of their absorption properties were conducted using rigorous coupled wave analysis. Both the calculated and measured absorbance results demonstrated that these MPMAs can realize strong selective absorption at wavelengths beyond the period of the array by varying the micropatch width. Absorbance values greater than 90% were achieved. Dual- or single-mode absorption can also be selected by varying the width of the Si posts. Pixel structures using such MPMAs could be used as high responsivity, high resolution and fast uncooled IR sensors.

  8. Nonventing, Regenerable, Lightweight Heat Absorber

    NASA Technical Reports Server (NTRS)

    Izenson, Michael G.; Chen, Weibo

    2008-01-01

    A lightweight, regenerable heat absorber (RHA), developed for rejecting metabolic heat from a space suit, may also be useful on Earth for short-term cooling of heavy protective garments. Unlike prior space-suit-cooling systems, a system that includes this RHA does not vent water. The closed system contains water reservoirs, tubes through which water is circulated to absorb heat, an evaporator, and an absorber/radiator. The radiator includes a solution of LiCl contained in a porous material in titanium tubes. The evaporator cools water that circulates through a liquid-cooled garment. Water vapor produced in the evaporator enters the radiator tubes where it is absorbed into the LiCl solution, releasing heat. Much of the heat of absorption is rejected to the environment via the radiator. After use, the RHA is regenerated by heating it to a temperature of 100 C for about 2 hours to drive the absorbed water back to the evaporator. A system including a prototype of the RHA was found to be capable of maintaining a temperature of 20 C while removing heat at a rate of 200 W for 6 hours.

  9. Characterization and dosimetry of a practical X-ray alternative to self-shielded gamma irradiators

    NASA Astrophysics Data System (ADS)

    Mehta, Kishor; Parker, Andrew

    2011-01-01

    The Insect Pest Control Laboratory of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture recently purchased an X-ray irradiator as part of their programme to develop the sterile insect technique (SIT). It is a self-contained type with a maximum X-ray beam energy of 150 keV using a newly developed 4 π X-ray tube to provide a very uniform dose to the product. This paper describes the results of our characterization study, which includes determination of dose rate in the centre of a canister as well as establishing absorbed dose distribution in the canister. The irradiation geometry consists of five canisters rotating around an X-ray tube—the volume of each canister being 3.5 l. The dose rate at the maximum allowed power of the tube (about 6.75 kW) in the centre of a canister filled with insects (or a simulated product) is about 14 Gy min -1. The dose uniformity ratio is about 1.3. The dose rate was measured using a Farmer type 0.18-cm 3 ionization chamber calibrated at the relevant low photon energies. Routine absorbed dose measurement and absorbed dose mapping can be performed using a Gafchromic® film dosimetry system. The radiation response of Gafchromic film is almost independent of X-ray energy in the range 100-150 keV, but is very sensitive to the surrounding material with which it is in immediate contact. It is important, therefore, to ensure that all absorbed dose measurements are performed under identical conditions to those used for the calibration of the dosimetry system. Our study indicates that this X-ray irradiator provides a practical alternative to self-shielded gamma irradiators for SIT programmes. Food and Agriculture Organization/International Atomic Energy Agency.

  10. Damage tolerant light absorbing material

    DOEpatents

    Lauf, R.J.; Hamby, C. Jr.; Akerman, M.A.; Seals, R.D.

    1993-09-07

    A light absorbing article comprised of a composite of carbon-bonded carbon fibers, is prepared by: blending carbon fibers with a carbonizable organic powder to form a mixture; dispersing the mixture into an aqueous slurry; vacuum molding the aqueous slurry to form a green article; drying and curing the green article to form a cured article; and, carbonizing the cured article at a temperature of at least about 1000 C to form a carbon-bonded carbon fiber light absorbing composite article having a bulk density less than 1 g/cm[sup 3]. 9 figures.

  11. Damage tolerant light absorbing material

    DOEpatents

    Lauf, Robert J.; Hamby, Jr., Clyde; Akerman, M. Alfred; Seals, Roland D.

    1993-01-01

    A light absorbing article comprised of a composite of carbon-bonded carbon fibers, prepared by: blending carbon fibers with a carbonizable organic powder to form a mixture; dispersing the mixture into an aqueous slurry; vacuum molding the aqueous slurry to form a green article; drying and curing the green article to form a cured article; and, carbonizing the cured article at a temperature of at least about 1000.degree. C. to form a carbon-bonded carbon fiber light absorbing composite article having a bulk density less than 1 g/cm.sup.3.

  12. Adaptive inertial shock-absorber

    NASA Astrophysics Data System (ADS)

    Faraj, Rami; Holnicki-Szulc, Jan; Knap, Lech; Seńko, Jarosław

    2016-03-01

    This paper introduces and discusses a new concept of impact absorption by means of impact energy management and storage in dedicated rotating inertial discs. The effectiveness of the concept is demonstrated in a selected case-study involving spinning management, a recently developed novel impact-absorber. A specific control technique performed on this device is demonstrated to be the main source of significant improvement in the overall efficiency of impact damping process. The influence of various parameters on the performance of the shock-absorber is investigated. Design and manufacturing challenges and directions of further research are formulated.

  13. Laser ablation of absorbing liquids under transparent cover: acoustical and optical monitoring

    NASA Astrophysics Data System (ADS)

    Samokhin, A. A.; Il'ichev, N. N.; Pivovarov, P. A.; Sidorin, A. V.

    2016-06-01

    Phase transition induced with infrared (λ = 2920 nm and λ = 2940 nm) nanosecond laser pulses in strongly absorbing liquids (water, ethanol) under transparent solid cover is investigated with the help of acoustical and optical monitoring. LiNbO3 transducer is used for registration of pressure pulses generated in irradiated liquids. Optical signals due to scattering and specular reflection of probing optical beams are explored with the schemes involving total internal reflection and interference effects. Combination of these two optical diagnostic methods permits for the first time to show that irradiation of covered liquids leads to vapor cavity formation which is divided from the cover with thin (submicron) liquid film despite the fact that radiation intensity maximum is located just at the liquid-plate boundary. The cavity formation is due to explosive boiling which occurs when the superheated liquid reaches its superheating limit in near critical region. After the first acoustical signal, the second signal is observed with several hundreds microseconds time delay which is caused by the vapor cavity collapse. Some results of optical and acoustical diagnostics in the case of free liquid surface are also presented.

  14. Distinct EUV minimum of the solar irradiance (16-40 nm) observed by SolACES spectrometers onboard the International Space Station (ISS) in August/September 2009

    NASA Astrophysics Data System (ADS)

    Nikutowski, B.; Brunner, R.; Erhardt, Ch.; Knecht, St.; Schmidtke, G.

    2011-09-01

    In the field of terrestrial climatology the continuous monitoring of the solar irradiance with highest possible accuracy is an important goal. SolACES as a part of the ESA mission SOLAR on the ISS is measuring the short-wavelength solar EUV irradiance from 16-150 nm. This data will be made available to the scientific community to investigate the impact of the solar irradiance variability on the Earth's climate as well as the thermospheric/ionospheric interactions that are pursued in the TIGER program. Since the successful launch with the shuttle mission STS-122 on February 7th, 2008, SolACES initially recorded the low EUV irradiance during the extended solar activity minimum. Thereafter it has been observing the EUV irradiance during the increasing solar activity with enhanced intensity and changing spectral composition. SolACES consists of three grazing incidence planar grating spectrometers. In addition there are two three-signal ionisation chambers, each with exchangeable band-pass filters to determine the absolute EUV fluxes repeatedly during the mission. One important problem of space-borne instrumentation recording the solar EUV irradiance is the degradation of the spectrometer sensitivity. The two double ionisation chambers of SolACES, which could be re-filled with three different gases for each recording, allow the recalibration of the efficiencies of the three SolACES spectrometers from time to time.

  15. Progress on the MICE Liquid Absorber Cooling and CryogenicDistribution System

    SciTech Connect

    Green, M.A.; Baynham, E.; Bradshaw, T.; Drumm, P.; Ivanyushenkov,Y.; Ishimoto, S.; Cummings, M.A.C.; Lau, W.W.; Yang, S.Q.

    2005-05-13

    This report describes the progress made on the design of the cryogenic cooling system for the liquid absorber for the international Muon Ionization Cooling Experiment (MICE). The absorber consists of a 20.7-liter vessel that contains liquid hydrogen (1.48 kg at 20.3 K) or liquid helium (2.59 kg at 4.2 K). The liquid cryogen vessel is located within the warm bore of the focusing magnet for the MICE. The purpose of the magnet is to provide a low beam beta region within the absorber. For safety reasons, the vacuum vessel for the hydrogen absorber is separated from the vacuum vessel for the superconducting magnet and the vacuum that surrounds the RF cavities or the detector. The absorber thin windows separate the liquid in the absorber from the absorber vacuum. The absorber vacuum vessel also has thin windows that separate the absorber vacuum space from adjacent vacuum spaces. Because the muon beam in MICE is of low intensity, there is no beam heating in the absorber. The absorber can use a single 4 K cooler to cool either liquid helium or liquid hydrogen within the absorber.

  16. New Green Polymeric Composites Based on Hemp and Natural Rubber Processed by Electron Beam Irradiation

    PubMed Central

    Stelescu, Maria-Daniela; Craciun, Gabriela; Dumitrascu, Maria

    2014-01-01

    A new polymeric composite based on natural rubber reinforced with hemp has been processed by electron beam irradiation and characterized by several methods. The mechanical characteristics: gel fraction, crosslink density, water uptake, swelling parameters, and FTIR of natural rubber/hemp fiber composites have been investigated as a function of the hemp content and absorbed dose. Physical and mechanical properties present a significant improvement as a result of adding hemp fibres in blends. Our experiments showed that the hemp fibers have a reinforcing effect on natural rubber similar to mineral fillers (chalk, carbon black, silica). The crosslinking rates of samples, measured using the Flory-Rehner equation, increase as a result of the amount of hemp in blends and the electron beam irradiation dose increasing. The swelling parameters of samples significantly depend on the amount of hemp in blends, because the latter have hydrophilic characteristics. PMID:24688419

  17. Counterflow absorber for an absorption refrigeration system

    DOEpatents

    Reimann, Robert C.

    1984-01-01

    An air-cooled, vertical tube absorber for an absorption refrigeration system is disclosed. Strong absorbent solution is supplied to the top of the absorber and refrigerant vapor is supplied to the bottom of the absorber to create a direct counterflow of refrigerant vapor and absorbent solution in the absorber. The refrigeration system is designed so that the volume flow rate of refrigerant vapor in the tubes of the absorber is sufficient to create a substantially direct counterflow along the entire length of each tube in the absorber. This provides several advantages for the absorber such as higher efficiency and improved heat transfer characteristics, and allows improved purging of non-condensibles from the absorber.

  18. Oil and fat absorbing polymers

    NASA Technical Reports Server (NTRS)

    Marsh, H. E., Jr. (Inventor)

    1977-01-01

    A method is described for forming a solid network polymer having a minimal amount of crosslinking for use in absorbing fats and oils. The polymer remains solid at a swelling ratio in oil or fat of at least ten and provides an oil absorption greater than 900 weight percent.

  19. Increased long-term expression of pentraxin 3 in irradiated human arteries and veins compared to internal controls from free tissue transfers

    PubMed Central

    2013-01-01

    Background Clinical studies have shown that radiotherapy increases the risk of cardiovascular disease at irradiated sites years after exposure. However, there is a lack of biological explanations in humans. We therefore examined human blood vessels exposed to radiotherapy and studied C-reactive protein (CRP) and pentraxin 3 (PTX3), a new marker for adverse cardiovascular outcome dependent on TNF- alpha (TNFα) or interleukin-1beta (IL-1β) expression. Methods Pairs of irradiated and non-irradiated human conduit arteries and veins were harvested from the same patient during autologous free tissue transfer for cancer-reconstruction at a median time of 48 weeks after radiotherapy. Differential gene expression was studied using qRT-PCR, confirmed by immunohistochemistry and cellular origins determined by immunofluorescence. Results Gene expression in irradiated arteries compared to non-irradiated showed a consistent up-regulation of PTX3 in all patients and in a majority of veins (p < 0.001). Both TNFα and IL-1β were increased in irradiated compared to non-irradiated arteries (p < 0.01) and IL-1β correlated to the PTX3 expression (p = 0.017). Immunohistochemical and immunofluorescence staining confirmed an increased expression of PTX3 in endothelial cells, macrophages and smooth muscle cells. Conclusions The sustained expression of PTX3 in arteries and veins tie biological evidence in humans to clinical studies and encourage further exploration of innate immunity in the pathogenesis of a radiation-induced vasculopathy. PMID:24060373

  20. Identification of peptides that bind to irradiated pancreatic tumor cells

    SciTech Connect

    Huang Canhui; Liu, Xiang Y.; Rehemtulla, Alnawaz; Lawrence, Theodore S. . E-mail: tsl@med.umich.edu

    2005-08-01

    Purpose: Peptides targeting tumor vascular cells or tumor cells themselves have the potential to be used as vectors for delivering either DNA in gene therapy or antitumor agents in chemotherapy. We wished to determine if peptides identified by phage display could be used to target irradiated pancreatic cancer cells. Methods and Materials: Irradiated Capan-2 cells were incubated with 5 x 10{sup 12} plaque-forming units of a phage display library. Internalized phage were recovered and absorbed against unirradiated cells. After five such cycles of enrichment, the recovered phage were subjected to DNA sequencing analysis and synthetic peptides made. The binding of both phage and synthetic peptides was evaluated by fluorescence staining and flow cytometry in vitro and in vivo. Results: We identified one 12-mer peptide (PA1) that binds to irradiated Capan-2 pancreatic adenocarcinoma cells but not to unirradiated cells. The binding of peptide was significant after 48 h incubation with cells. In vivo experiments with Capan-2 xenografts in nude mice demonstrated that these small peptides are able to penetrate tumor tissue after intravenous injections and bind specifically to irradiated tumor cells. Conclusion: These data suggest that peptides can be identified that target tumors with radiation-induced cell markers and may be clinically useful.

  1. Genetic effects induced by neutrons in Drosophila melanogaster I. Determination of absorbed dose.

    PubMed

    Delfin, A; Paredes, L C; Zambrano, F; Guzmán-Rincón, J; Ureña-Nuñez, F

    2001-12-01

    A method to obtain the absorbed dose in Drosophila melanogaster irradiated in the thermal column facility of the Triga Mark III Reactor has been developed. The method is based on the measurements of neutron activation of gold foils produced by neutron capture to obtain the neutron fluxes. These fluxes, combined with the calculations of kinetic energy released per unit mass, enables one to obtain the absorbed doses in Drosophila melanogaster. PMID:11761104

  2. [Study of new blended chemical absorbents to absorb CO2].

    PubMed

    Wang, Jin-Lian; Fang, Meng-Xiang; Yan, Shui-Ping; Luo, Zhong-Yang; Cen, Ke-Fa

    2007-11-01

    Three kinds of blended absorbents were investigated on bench-scale experimental bench according to absorption rate and regeneration grade to select a reasonable additive concentration. The results show that, among methyldiethanolamine (MDEA) and piperazine (PZ) mixtures, comparing MDEA : PZ = 1 : 0.4 (m : m) with MDEA : PZ = 1 : 0.2 (m : m), the absorption rate is increased by about 70% at 0.2 mol x mol(-1). When regeneration lasting for 40 min, regeneration grade of blended absorbents with PZ concentration of 0.2, 0.4, and 0.8 is decreased to 83.06%, 77.77% and 76.67% respectively while 91.04% for PZ concentration of 0. MDEA : PZ = 1 : 0.4(m : m) is a suitable ratio for MDEA/PZ mixtures as absorption and regeneration properties of the blended absorbents are all improved. The aqueous blends with 10% primary amines and 2% tertiary amines could keep high CO2 absorption rate, and lower regeneration energy consumption. Adding 2% 2-Amino-2-methyl-1-propanol (AMP) to 10% diethanolamine (DEA), the blended amine solvents have an advantage in absorption and regeneration properties over other DEA/AMP mixtures. Blended solvents, which consist of a mixture of primary amines with a small amount of tertiary amines, have the highest absorption rate among the three. And mixed absorbents of secondary amines and a small amount of sterically hindered amines have the best regeneration property. To combine absorption and regeneration properties, blends with medium activator addition to tertiary amines are competitive. PMID:18290495

  3. Nanowire heating by optical electromagnetic irradiation.

    PubMed

    Roder, Paden B; Pauzauskie, Peter J; Davis, E James

    2012-11-20

    The dissipative absorption of electromagnetic energy by 1D nanoscale structures at optical frequencies is applicable to several important phenomena, including biomedical photothermal theranostics, nanoscale photovoltaic materials, atmospheric aerosols, and integrated photonic devices. Closed-form analytical calculations are presented for the temperature rise within infinite circular cylinders with nanometer-scale diameters (nanowires) that are irradiated at right angles by a continuous-wave laser source polarized along the nanowire's axis. Solutions for the heat source are compared to both numerical finite-difference time domain (FDTD) simulations and well-known Mie scattering cross sections for infinite cylinders. The analysis predicts that the maximum temperature increase is affected not only by the cylinder's composition and porosity but also by morphology-dependent resonances (MDRs) that lead to significant spikes in the local temperature at particular diameters. Furthermore, silicon nanowires with high thermal conductivities are observed to exhibit extremely uniform internal temperatures during electromagnetic heating to 1 part in 10(6), including cases where there are substantial fluctuations of the internal electric-field source term that generates the Joule heating. For a highly absorbing material such as carbon, much higher temperatures are predicted, the internal temperature distribution is nonuniform, and MDRs are not encountered. PMID:23061375

  4. High-Efficiency Absorber for Damping the Transverse Wake Fields

    SciTech Connect

    Novokhatski, A.; Seeman, J.; Weathersby, S.; /SLAC

    2007-02-28

    Transverse wake fields generated by intense beams may propagate long distances in the vacuum chamber and dissipate power in different shielded elements such as bellows, vacuum valves or vacuum pumps. Induced heating in these elements may be high enough to deteriorate vacuum conditions. We have developed a broadband water-cooled bellows-absorber to capture and damp these harmful transverse fields without impacting the longitudinal beam impedance. Experimental results at the PEP-II SLAC B-factory demonstrate high efficiency of this device. This absorber may be useful in other machines like synchrotron light sources or International Linear Collider.

  5. Computational determination of absorbed dose distributions from gamma ray sources

    NASA Astrophysics Data System (ADS)

    Zhou, Chuanyu; Inanc, Feyzi

    2001-04-01

    A biomedical procedure known as brachytherapy involves insertion of many radioactive seeds into a sick gland for eliminating sick tissue. For such implementations, the spatial distribution of absorbed dose is very important. A simulation tool has been developed to determine the spatial distribution of absorbed dose in heterogeneous environments where the gamma ray source consists of many small internal radiation emitters. The computation is base on integral transport method and the computations are done in a parallel fashion. Preliminary results involving 137Cs and 125I sources surrounded by water and comparison of the results to the experimental and computational data available in the literature are presented.

  6. High-efficiency absorber for damping transverse wakefields

    NASA Astrophysics Data System (ADS)

    Novokhatski, A.; Seeman, J.; Weathersby, S.

    2007-04-01

    Transverse wakefields generated by intense beams may propagate long distances in a vacuum chamber and dissipate power in different shielded elements such as bellows, vacuum valves, or vacuum pumps. Induced heating in these elements may be high enough to deteriorate vacuum conditions. We have developed a broadband water-cooled bellows absorber to capture and damp these harmful transverse fields without impacting the longitudinal beam impedance. Experimental results at the PEP-II SLAC B-factory demonstrate a high efficiency for this device. This absorber may be useful in super B-factories, the International Linear Collider, the Large Hadron Collider, or synchrotron light sources.

  7. Single scattering properties of semi-embedded soot morphologies with intersecting and non-intersecting surfaces of absorbing spheres and non-absorbing host

    NASA Astrophysics Data System (ADS)

    Wu, Yu; Cheng, Tianhai; Zheng, Lijuan; Chen, Hao; Xu, Hui

    2015-05-01

    The optical properties of light absorbing soot aerosols generally change through interactions with weakly absorbing particles, resulting in complex mixing states, and have been highlighted as a major uncertainty in assessing their radiative forcing and climatic impact. The single scattering properties of soot aggregates partially embedded in the host sulfate particle (semi-embedded soot-containing mixtures) are investigated for two kinds of morphologies with intersecting and non-intersecting surfaces. The surfaces cannot be overlapped in the non-intersecting surface morphology, while the intersecting surface morphology is unconstrained. Based on the modified diffusion limited aggregation (DLA) algorithm, the models with non-intersecting surfaces are simulated and applied for the single scattering calculations of semi-embedded soot-containing mixtures using the superposition T-matrix (STM) method. For comparison, the models with intersecting surfaces are simulated with the same morphological parameters, but some soot monomers are intersected by the host sphere. Due to the limitation of current STM method, the optical properties of these models with intersecting surfaces are calculated using the discrete dipole approximation (DDA) method. The soot volume fractions outside sulfate host (Fs,out) are introduced and applied to characterize the mixing states of the soot-containing aerosols. These simulations show that the absorption cross-sections of those internally, deeply, half and slightly embedded mixed soot particles (Fs,out = 0.0, 0.2, 0.5, 0.8) are ~105%, ~65%, ~43% and ~14% larger than the semi-external mixtures (Fs,out = 1.0), respectively. The results also indicate that the differences of extinction cross-sections, single scattering albedo (SSA) and asymmetry parameter (ASY) between simulations with intersecting and non-intersecting surfaces are small (<1%) for semi-embedded soot-containing mixtures with the same morphological parameters. Within the range of

  8. Fluorescence spectroscopy: considerations for highly absorbing dissolved organic matter samples

    NASA Astrophysics Data System (ADS)

    Simone, B. E.; Miller, M.; McKnight, D. M.

    2009-12-01

    Fluorescence spectroscopy is a robust method for characterizing organic matter (OM). However, proper collection and correction of spectra are necessary to provide useful data. One important correction is the inner-filter correction, which primarily accounts for the inner-filter effect by adjusting for the wavelength dependent attenuation of emitted light by the solution prior to detection by the fluorometer. The most commonly used correction is based on an assumption that light is emitted at the center of the pathlength. Thus, the inner-filter effect is more pronounced in highly absorbing samples, and has the potential to skew the fluorescence spectra. For this study, the terrestrially derived Suwannee River fulvic acid (SRFA) and microbially derived Pony Lake fulvic acid (PLFA), from the International Humic Substances Society (IHSS), were diluted to incremental absorbances at a wavelength of 254 nm from 0.05 to 1.0 at pH 4 and 7. Three dimensional fluorescence spectra were measured and modeled with the Cory and McKnight (2005) parallel factor analysis (PARAFAC) model which resolves the fluorescence spectra into 13 components, including quinone-like and protein-like components. In the absence of inner-filter effects, plots of absorbance vs. loadings should be linear. Using the data from absorbance of 0.05 to 0.3, where the inner-filter affect is least pronounced, a linear regression was created and used as a baseline to predict component loadings at higher absorbance values in the absence of inner-filter effects. Results indicate that at absorbance values greater than 0.3, the commonly-used inner-filter correction is not able to remove the inner-filter effect. Therefore, in order to obtain reliable component loadings and correctly interpret the spectra, samples should be diluted to absorbance values less than 0.3 at 254 nm prior to collection of three dimensional fluorescence scans. The recommendation of a maximum absorbance of 0.3 agrees with the results of a

  9. An international comparison of mass fraction purity assignment of digoxin: The Comité Consultatif pour la Quantité de Matière (CCQM) Pilot Study CCQM-P20.f (Digoxin)

    NASA Astrophysics Data System (ADS)

    Westwood, S.; Josephs, R.; Choteau, T.; Mesquida, C.; Daireaux, A.; Wielgosz, R.; Davies, S.; Windust, A.; Kang, M.; Ting, H.; Kato, K.; Frias, E.; Pérez, M.; Apps, P.; Fernandes-Whaley, M.; Wiangnon, K.; Ruangrittinon, N.; Wood, S.; LeGoff, T.; Duewer, D.; Schantz, M.; Siekmann, L.; Esker, J.

    2011-01-01

    Under the auspices of the Organic Analysis Working Group (OAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) a laboratory comparison, CCQM-P20.f, was coordinated by the Bureau International des Poids et Mesures (BIPM) in 2007/2008. Nine national measurement institutes, four expert laboratories and the BIPM participated in the comparison. Participants were required to assign the mass fraction of digoxin present as the main component in the comparison sample (CCQM-P20.f) which consisted of digoxin material obtained from a commercial supplier stated to comply with USP requirements. In addition to assigning the mass fraction content of digoxin for the material, participants were requested, but not obliged, to provide mass fraction estimates for the minor components they identified in each sample. In contrast with the previous round of the CCQM-P20 series, in which the mass fraction content of theophylline in two comparison samples (CCQM-P20.e.1 and CCQM-P20.e.2) was determined, a wider range of results were reported for the mass fraction content of digoxin in the CCQM-P20.f comparison. A minority of participants did not appear to use conditions capable of fully resolving and/or quantifying the major related structure impurities present in the comparison sample. Among those that did achieve suitable separations, there was further variation in their reported quantifications of the individual and total related substance content which reflected in part the limited availability of reference standards for these materials and the resulting assumptions that had to be made regarding the structure and response factors relative to digoxin for each individual impurity. This was particularly relevant because of the span of molecular masses of the impurities present in the sample, which ranged from aglycones to glycones with tetrameric carbohydrate chains, relative to that of digoxin. A significant additional factor also contributed to the observed variation of

  10. Polymeric near-infrared absorbing dendritic nanogels for efficient in vivo photothermal cancer therapy.

    PubMed

    Molina, Maria; Wedepohl, Stefanie; Calderón, Marcelo

    2016-03-10

    In recent years, several near-infrared light absorbing inorganic nanomaterials have been developed for photothermal therapy. However, their biological fate after injection limits their clinical utilization. In this work, we developed a novel polymeric near-infrared light absorbing material based on a biocompatible thermoresponsive nanogel that is semi-interpenetrated with polyaniline, a conjugated polymer with strong near-infrared absorbance. This polymeric nanocomposite generates heat after being irradiated by NIR light, thereby inducing a local hyperthermia that is used for photothermal cancer therapy in vitro and in vivo. PMID:26931077

  11. Self-assembly of highly efficient, broadband plasmonic absorbers for solar steam generation.

    PubMed

    Zhou, Lin; Tan, Yingling; Ji, Dengxin; Zhu, Bin; Zhang, Pei; Xu, Jun; Gan, Qiaoqiang; Yu, Zongfu; Zhu, Jia

    2016-04-01

    The study of ideal absorbers, which can efficiently absorb light over a broad range of wavelengths, is of fundamental importance, as well as critical for many applications from solar steam generation and thermophotovoltaics to light/thermal detectors. As a result of recent advances in plasmonics, plasmonic absorbers have attracted a lot of attention. However, the performance and scalability of these absorbers, predominantly fabricated by the top-down approach, need to be further improved to enable widespread applications. We report a plasmonic absorber which can enable an average measured absorbance of ~99% across the wavelengths from 400 nm to 10 μm, the most efficient and broadband plasmonic absorber reported to date. The absorber is fabricated through self-assembly of metallic nanoparticles onto a nanoporous template by a one-step deposition process. Because of its efficient light absorption, strong field enhancement, and porous structures, which together enable not only efficient solar absorption but also significant local heating and continuous stream flow, plasmonic absorber-based solar steam generation has over 90% efficiency under solar irradiation of only 4-sun intensity (4 kW m(-2)). The pronounced light absorption effect coupled with the high-throughput self-assembly process could lead toward large-scale manufacturing of other nanophotonic structures and devices. PMID:27152335

  12. [Absorbable coronary stents. New promising technology].

    PubMed

    Erbel, Raimund; Böse, Dirk; Haude, Michael; Kordish, Igor; Churzidze, Sofia; Malyar, Nasser; Konorza, Thomas; Sack, Stefan

    2007-06-01

    Coronary stent implantation started in Germany 20 years ago. In the beginning, the progress was very slow and accelerated 10 years later. Meanwhile, coronary stent implantation is a standard procedure in interventional cardiology. From the beginning of permanent stent implantation, research started to provide temporary stenting of coronary arteries, first with catheter-based systems, later with stent-alone technology. Stents were produced from polymers or metal. The first polymer stent implantation failed except the Igaki-Tamai stent in Japan. Newly developed absorbable polymer stents seem to be very promising, as intravascular ultrasound (IVUS) and optical coherence tomography have demonstrated. Temporary metal stents were developed based on iron and magnesium. Currently, the iron stent is tested in peripheral arteries. The absorbable magnesium stent (Biotronik, Berlin, Germany) was tested in peripheral arteries below the knee and meanwhile in the multicenter international PROGRESS-AMS (Clinical Performance and Angiographic Results of Coronary Stenting with Absorbable Metal Stents) study. The first magnesium stent implantation was performed on July 30, 2004 after extended experimental testing in Essen. The magnesium stent behaved like a bare-metal stent with low recoil of 5-7%. The stent struts were absorbed when tested with IVUS. Stent struts were not visible by fluoroscopy or computed tomography (CT) as well as magnetic resonance imaging (MRI). That means, that the magnesium stent is invisible and therefore CT and MRI can be used for imaging of interventions. Only using micro-CT the stent struts were visible. The absorption process could be demonstrated in a patient 18 days after implantation due to suspected acute coronary syndrome, which was excluded. IVUS showed a nice open lumen. Stent struts were no longer visible, but replaced by tissue indicating the previous stent location. Coronary angiography after 4 months showed an ischemia-driven target lesion

  13. Simultaneous measurements of absorbed dose and linear energy transfer in therapeutic proton beams

    NASA Astrophysics Data System (ADS)

    Granville, Dal A.; Sahoo, Narayan; Sawakuchi, Gabriel O.

    2016-02-01

    The biological response resulting from proton therapy depends on both the absorbed dose in the irradiated tissue and the linear energy transfer (LET) of the beam. Currently, optimization of proton therapy treatment plans is based only on absorbed dose. However, recent advances in proton therapy delivery have made it possible to vary the LET distribution for potential therapeutic gain, leading to investigations of using LET as an additional parameter in plan optimization. Having a method to measure and verify both absorbed dose and LET as part of a quality assurance program would be ideal for the safe delivery of such plans. Here we demonstrated the potential of an optically stimulated luminescence (OSL) technique to simultaneously measure absorbed dose and LET. We calibrated the ratio of ultraviolet (UV) to blue emission intensities from Al2O3:C OSL detectors as a function of LET to facilitate LET measurements. We also calibrated the intensity of the blue OSL emission for absorbed dose measurements and introduced a technique to correct for the LET-dependent dose response of OSL detectors exposed to therapeutic proton beams. We demonstrated the potential of our OSL technique by using it to measure LET and absorbed dose under new irradiation conditions, including patient-specific proton therapy treatment plans. In the beams investigated, we found the OSL technique to measure dose-weighted LET within 7.9% of Monte Carlo-simulated values and absorbed dose within 2.5% of ionization chamber measurements.

  14. Simultaneous measurements of absorbed dose and linear energy transfer in therapeutic proton beams.

    PubMed

    Granville, Dal A; Sahoo, Narayan; Sawakuchi, Gabriel O

    2016-02-21

    The biological response resulting from proton therapy depends on both the absorbed dose in the irradiated tissue and the linear energy transfer (LET) of the beam. Currently, optimization of proton therapy treatment plans is based only on absorbed dose. However, recent advances in proton therapy delivery have made it possible to vary the LET distribution for potential therapeutic gain, leading to investigations of using LET as an additional parameter in plan optimization. Having a method to measure and verify both absorbed dose and LET as part of a quality assurance program would be ideal for the safe delivery of such plans. Here we demonstrated the potential of an optically stimulated luminescence (OSL) technique to simultaneously measure absorbed dose and LET. We calibrated the ratio of ultraviolet (UV) to blue emission intensities from Al2O3:C OSL detectors as a function of LET to facilitate LET measurements. We also calibrated the intensity of the blue OSL emission for absorbed dose measurements and introduced a technique to correct for the LET-dependent dose response of OSL detectors exposed to therapeutic proton beams. We demonstrated the potential of our OSL technique by using it to measure LET and absorbed dose under new irradiation conditions, including patient-specific proton therapy treatment plans. In the beams investigated, we found the OSL technique to measure dose-weighted LET within 7.9% of Monte Carlo-simulated values and absorbed dose within 2.5% of ionization chamber measurements. PMID:26859539

  15. Batch-Equilibrium Hot-Cell Tests of Caustic-Side Solvent Extraction (CSSX) with SRS Simulant Waste and Internal 137Cs Irradiation

    SciTech Connect

    Spence, R.D.

    2001-09-17

    The solvent was loaded with {sup 137}Cs and subsamples were stored on a shaker table while in contact with the extract, scrub, or strip aqueous phases. Evidence of solvent degradation was evaluated at exposure times of 0, 20, 54, and 83 days. This resulted in estimated solvent doses ranging up to 1.24 Mrad, equivalent to the dose expected to be received during 16.5 years of operation at the plant proposed for the Savannah River Site. The break times and distribution of cesium of the batch samples remained constant within experimental error; in addition, no third-phase formation was observed. The solvent concentrations of calix[4]arene-bis-(tert-octylbenzo-crown-6) and 1-(2,2,3,3-tetra-fluoroproproxy)-3-(4-sec-butylphenoxy)-2-propanol remained constant within experimental error. Solvent degradation with irradiation was evidenced by a decrease in the trioctylamine (TOA) concentration in the solvent and an increase in the solvent concentration of the degradation product 4-sec-butylphenol. No decline in extraction or scrubbing performance of the irradiated solvents was observed. The stripping performance of the solvent was seriously impaired with irradiation; however, a mild caustic wash and replenishment of the TOA concentration restored the ability to strip the irradiated solvent.

  16. Energy-Absorbing, Lightweight Wheels

    NASA Technical Reports Server (NTRS)

    Waydo, Peter

    2003-01-01

    Improved energy-absorbing wheels are under development for use on special-purpose vehicles that must traverse rough terrain under conditions (e.g., extreme cold) in which rubber pneumatic tires would fail. The designs of these wheels differ from those of prior non-pneumatic energy-absorbing wheels in ways that result in lighter weights and more effective reduction of stresses generated by ground/wheel contact forces. These wheels could be made of metals and/or composite materials to withstand the expected extreme operating conditions. As shown in the figure, a wheel according to this concept would include an isogrid tire connected to a hub via spring rods. The isogrid tire would be a stiff, lightweight structure typically made of aluminum. The isogrid aspect of the structure would both impart stiffness and act as a traction surface. The hub would be a thin-walled body of revolution having a simple or compound conical or other shape chosen for structural efficiency. The spring rods would absorb energy and partially isolate the hub and the supported vehicle from impact loads. The general spring-rod configuration shown in the figure was chosen because it would distribute contact and impact loads nearly evenly around the periphery of the hub, thereby helping to protect the hub against damage that would otherwise be caused by large loads concentrated onto small portions of the hub.

  17. Practical dosimetric aspects of blood and blood product irradiation

    SciTech Connect

    Fearon, T.C.; Luban, N.L.

    1986-09-01

    The method of choice to reduce susceptibility to transfusion-transmitted graft-versus-host disease is irradiation of allogenic blood and blood products for transfusion to immunosuppressed recipients. Optimal irradiation requires delivery of a known and homogeneous absorbed dose. The use of absorbed dose in air measured at the center of the irradiation volume without proper compensation for sample absorption can lead to approximately 20 percent underexposure. A lucite cylinder was used to provide the delivery of a homogeneous irradiation dose to blood products of different volumes by allowing rotation of the product.

  18. Scattering Properties of Heterogeneous Mineral Particles with Absorbing Inclusions

    NASA Technical Reports Server (NTRS)

    Dlugach, Janna M.; Mishchenko, Michael I.

    2015-01-01

    We analyze the results of numerically exact computer modeling of scattering and absorption properties of randomly oriented poly-disperse heterogeneous particles obtained by placing microscopic absorbing grains randomly on the surfaces of much larger spherical mineral hosts or by imbedding them randomly inside the hosts. These computations are paralleled by those for heterogeneous particles obtained by fully encapsulating fractal-like absorbing clusters in the mineral hosts. All computations are performed using the superposition T-matrix method. In the case of randomly distributed inclusions, the results are compared with the outcome of Lorenz-Mie computations for an external mixture of the mineral hosts and absorbing grains. We conclude that internal aggregation can affect strongly both the integral radiometric and differential scattering characteristics of the heterogeneous particle mixtures.

  19. Experimental and Mathematical Evaluation of Dynamic Behaviour of AN Oil-Air Coupling Shock Absorber

    NASA Astrophysics Data System (ADS)

    PING, Y.

    2003-11-01

    The physical mechanism of the actual shock absorber with multi-types of damping and non-linear stiffness through coupling the oil, air, rubber and spring by ingenious devices is systematically investigated. The experimental results of the key-model machine in multi-parameter coupling dynamic test show complex non-linearity dynamic characteristics. Based on this, the non-linear dynamic model for the shock absorber is presented by analysing the internal fluid dynamic phenomenon with respect to the shock absorber. Comparisons with experimental data confirm the validity of the model. Using the model, it is possible to evaluate the importance of different factors for designing the shock absorber.

  20. Food irradiation in perspective

    NASA Astrophysics Data System (ADS)

    Henon, Y. M.

    1995-02-01

    Food irradiation already has a long history of hopes and disappointments. Nowhere in the world it plays the role that it should have, including in the much needed prevention of foodborne diseases. Irradiated food sold well wherever consumers were given a chance to buy them. Differences between national regulations do not allow the international trade of irradiated foods. While in many countries food irradiation is still illegal, in most others it is regulated as a food additive and based on the knowledge of the sixties. Until 1980, wholesomeness was the big issue. Then the "prerequisite" became detection methods. Large amounts of money have been spent to design and validate tests which, in fact, aim at enforcing unjustified restrictions on the use of the process. In spite of all the difficulties, it is believed that the efforts of various UN organizations and a growing legitimate demand for food safety should in the end lead to recognition and acceptance.

  1. 26 CFR 26.2642-4 - Redetermination of applicable fraction.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 14 2010-04-01 2010-04-01 false Redetermination of applicable fraction. 26.2642....2642-4 Redetermination of applicable fraction. (a) In general. The applicable fraction for a trust is... the redetermined applicable fraction is the sum of the amount of GST exemption currently...

  2. 26 CFR 26.2642-4 - Redetermination of applicable fraction.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 14 2011-04-01 2010-04-01 true Redetermination of applicable fraction. 26.2642....2642-4 Redetermination of applicable fraction. (a) In general. The applicable fraction for a trust is... the redetermined applicable fraction is the sum of the amount of GST exemption currently...

  3. High-precision temperature determination of evaporating light-absorbing and non-light-absorbing droplets.

    PubMed

    Derkachov, G; Jakubczyk, D; Woźniak, M; Archer, J; Kolwas, M

    2014-10-30

    Models describing evaporation or condensation of a droplet have existed for over a century, and the temporal evolutions of droplet radius and temperature could be predicted. However, the accuracy of results was questionable, since the models contain free parameters and the means of accurate calibration were not available. In previous work (Hołyst et al. Soft Matter 2013, 9, 7766), a model with an efficacious parametrization in terms of the mean free path was proposed and calibrated with molecular dynamics numerical experiment. It was shown that it is essentially possible to determine reliably the temperature of a steadily evaporating/condensing homogeneous droplet relative to ambient temperature when the evolution of the droplet radius is known. The accuracy of such measurement can reach fractions of mK. In the case of an evaporating droplet of pure liquid, the (droplet) temperature is constant during the stationary stage of evaporation. In this paper, we show that, in many cases, it is also possible to determine the temporal evolution of droplet temperature from the evolution of the droplet radius if the droplet (initial) composition is known. We found the droplet radius evolution with high accuracy and obtained the evolution of droplet temperature (and composition) for droplets of (i) a two-component mixture of pure liquids; (ii) solutions of solid in liquid, one that is non-surface-active and another that is; and (iii) suspensions of non-light-absorbing and light-absorbing particles. PMID:25290035

  4. Influence of microwave irradiation on enzyme kinetics

    NASA Astrophysics Data System (ADS)

    Pavelkić, V. M.; Stanisavljev, D. R.; Gopčević, K. R.; Beljanski, M. V.

    2009-09-01

    The in vitro effect of 2.45 GHz microwave irradiation on porcine pepsin activity under controlled temperature and absorbed microwave power via kinetic parameters was evaluated. Kinetic study with respect of time of irradiation demonstrated the existence of an inactivation effect of microwaves at pH 2 on pepsin molecule. Bovine serum albumin (BSA)-bromphenol blue (BPB) complex was used as substrate for the assay of pepsin by kinetic method. Depending on absorbed microwave dose, the degree of caused inactivation varies from 39.11 to 45.91% for 5 and 20 min of pepsin MW irradiation, respectively. The V maxapp and K mapp were calculated for low (5 min of MW irradiation) and higher specific absorbed dose (20 min of MW irradiation), as well as for untreated enzyme, from double reciprocal Lineweaver-Burk plot. The effect of microwaves on substrate (BSA-BPB complex) was also investigated. For reaction performed with MW irradiated substrate for 5 min the reaction rate was decreased for 15.15%, while for 20 min of substrate irradiation reaction rate was decreased for 25.52% compared to the control reaction.

  5. Irradiating insect pests

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This is a non-technical article focusing on phytosanitary uses of irradiation. In a series of interview questions, I present information on the scope of the invasive species problem and the contribution of international trade in agricultural products to the movement of invasive insects. This is foll...

  6. Shock absorber operates over wide range

    NASA Technical Reports Server (NTRS)

    Creasy, W. K.; Jones, J. C.

    1965-01-01

    Piston-type hydraulic shock absorber, with a metered damping system, operates over a wide range of kinetic energy loading rates. It is used for absorbing shock and vibration on mounted machinery and heavy earth-moving equipment.

  7. Experimental characterization of a nonlinear vibration absorber using free vibration

    NASA Astrophysics Data System (ADS)

    Tang, Bin; Brennan, M. J.; Gatti, G.; Ferguson, N. S.

    2016-04-01

    Knowledge of the nonlinear characteristics of a vibration absorber is important if its performance is to be predicted accurately when connected to a host structure. This can be achieved theoretically, but experimental validation is necessary to verify the modelling procedure and assumptions. This paper describes the characterization of such an absorber using a novel experimental procedure. The estimation method is based on a free vibration test, which is appropriate for a lightly damped device. The nonlinear absorber is attached to a shaker which is operated such that the shaker works in its mass-controlled regime, which means that the shaker dynamics, which are also included in the measurement, are considerably simplified, which facilitates a simple estimation of the absorber properties. From the free vibration time history, the instantaneous amplitude and instantaneous damped natural frequency are estimated using the Hilbert transform. The stiffness and damping of the nonlinear vibration absorber are then estimated from these quantities. The results are compared with an analytical solution for the free vibration of the nonlinear system with cubic stiffness and viscous damping, which is also derived in the paper using an alternative approach to the conventional perturbation methods. To further verify the approach, the results are compared with a method in which the internal forces are balanced at each measured instant in time.

  8. Report From the International Atomic Energy Agency (IAEA) Consultants' Meeting on Elective Nodal Irradiation in Lung Cancer: Non-Small-Cell Lung Cancer (NSCLC)

    SciTech Connect

    Belderbos, Jose; Martel, Mary K.; Videtic, Gregory; Jeremic, Branislav

    2008-10-01

    Lymphatic spread is an important pathway of progression in non-small-cell lung cancer (NSCLC), along with local spread and distant metastasis. The probability of lymph node (LN) involvement is dependent on the site of the primary tumor, stage, and histology. Elective nodal irradiation (ENI) is the irradiation of clinical and radiological uninvolved LN to account for microscopic tumor invasion in these LNs because we have not been able to determine the extent of LN spread accurately. The clinical value of ENI is uncertain. The impact of ENI is dependent on many (staging-, treatment-, and patient-related) factors. The purpose of this report is to analyze the current status of ENI and to provide comprehensive in-depth analysis and guidance on how to generally approach this issue in NSCLC.

  9. Inactivation of Escherichia Coli O157:H7 Internalized in Romaine Lettuce and Baby Spinach Leaves:Sodium Hypochlorite Wash vs. Irradiation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pathogenic bacteria which are internalized in leaf tissues are protected from the antimicrobial effects of surface treatments. Ionizing radiation is known to penetrate foods, but the efficacy of the process against internalized bacteria is unknown. Leaves of romaine lettuce and baby spinach were cut...

  10. Irradiation Compared with Chlorination for Elimination of Escherichia Coli O157:H7 Internalized in Lettuce Leaves: Influence of Lettuce Variety

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pathogenic bacteria internalized in leaf tissues are not effectively removed by surface treatments. Ionizing radiation has been shown to inactivate leaf-internalized bacteria, but many aspects of targeting these protected pathogens remain unknown. Leaves of Iceberg, Boston, green leaf and red leaf l...

  11. Relative Efficacy of Sodium Hypochlorite Wash Versus Irradiation to Inactivate Escherichia coli O157:H7 Internalized in Leaves of Romaine Lettuce and Baby Spinach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pathogenic bacteria which are internalized in leaf tissues are protected from the antimicrobial effects of surface treatments. Ionizing radiation is known to penetrate foods, but the efficacy of the process against internalized bacteria is unknown. Leaves of romaine lettuce and baby spinach were cut...

  12. The Lack of Cytotoxic Effect and Radioadaptive Response in Splenocytes of Mice Exposed to Low Level Internal β-Particle Irradiation through Tritiated Drinking Water in Vivo

    PubMed Central

    Flegal, Matthew; Blimkie, Melinda; Roch-Lefevre, Sandrine; Gregoire, Eric; Klokov, Dmitry

    2013-01-01

    Health effects of tritium, a β-emitter and a by-product of the nuclear industry, is a subject of significant controversy. This mouse in vivo study was undertaken to monitor biological effects of low level tritium exposure. Mice were exposed to tritiated drinking water (HTO) at 10 KBq/L, 1 MBq/L and 20 MBq/L concentrations for one month. The treatment did not result in a significant increase of apoptosis in splenocytes. To examine if this low level tritium exposure alters radiosensitivity, the extracted splenocytes were challenged in vitro with 2 Gy γ-radiation, and apoptotic responses at 1 and 24 h were measured. No alterations in the radiosensitivity were detected in cells from mice exposed to tritium compared to sham-treated mice. In contrast, low dose γ-irradiation at 20 or 100 mGy, resulted in a significant increase in resistance to apoptotic cell death after 2 Gy irradiation; an indication of the radioadaptive response. Overall, our data suggest that low concentrations of tritium given to mice as HTO in drinking water do not exert cytotoxic effect in splenocytes, nor do they change cellular sensitivity to additional high dose γ-radiation. The latter may be considered as the lack of a radioadaptive response, typically observed after low dose γ-irradiation. PMID:24317437

  13. 21 CFR 872.6050 - Saliva absorber.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Saliva absorber. 872.6050 Section 872.6050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL... absorber is a device made of paper or cotton intended to absorb moisture from the oral cavity during...

  14. 21 CFR 872.6050 - Saliva absorber.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Saliva absorber. 872.6050 Section 872.6050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL... absorber is a device made of paper or cotton intended to absorb moisture from the oral cavity during...

  15. Improving the laboratory monitoring of absorbent oil

    SciTech Connect

    V.S. Shved; S.S. Sychev; I.V. Safina; S.A. Klykov

    2009-05-15

    The performance of absorbent coal tar oil is analyzed as a function of the constituent and group composition. The qualitative and quantitative composition of the oil that ensures the required absorbent properties is determined. Operative monitoring may be based on absorbent characteristics that permit regulation of the beginning and end of regeneration.

  16. Embedded absorbers for helicopter rotor lag damping

    NASA Astrophysics Data System (ADS)

    Byers, Lynn; Gandhi, Farhan

    2009-09-01

    Radial and chordwise damped vibration absorbers embedded in the rotor blade are compared for rotor lag damping augmentation. Results show that the radial absorber is more effective in transferring damping to the rotor blade lag mode. The chordwise absorber needs to be at a more outboard location and have a larger mass to introduce levels of lag damping comparable to that introduced by the radial absorber. The 1/rev amplitude of a chordwise absorber at the blade tip, per degree of blade lead-lag motion in forward flight, is of the order of 35% of the blade chord, and such a stroke might be difficult to accommodate. The 1/rev amplitude of a radial absorber at 70% span (having significantly lower mass than the chordwise absorber and producing comparable lag damping) is of the order of 4% of the rotor blade span. The static displacement of the radial absorber under centrifugal load needs to be limited using a frequency-dependent (high static stiffness, low dynamic stiffness) or nonlinear spring. The chordwise absorber can also undergo a large static displacement under the chordwise component of the centrifugal load if there is an offset from the feather axis, and this would again have to be limited using a strategy such as a frequency-dependent spring. Significant advantages of the radial absorber are—higher lag damping, lower absorber mass, space for absorber mass travel, and no chordwise travel of blade center of gravity reducing susceptibility to aeroelastic instability and dynamic pitch-link loads.

  17. Porcelain enamel neutron absorbing material

    DOEpatents

    Iverson, Daniel C.

    1990-02-06

    A porcelain enamel composition as a neutron absorbing material can be prepared of a major proportion by weight of a cadmium compound and a minor proportion of compounds of boron, lithium and silicon. These compounds in the form of a porcelain enamel coating or layer on several alloys has been found to be particularly effective in enhancing the nuclear safety of equipment for use in the processing and storage of fissile material. The composition of the porcelain enamel coating can be tailored to match the coefficient of thermal expansion of the equipment to be coated and excellent coating adhesion can be achieved.

  18. Porcelain enamel neutron absorbing material

    DOEpatents

    Iverson, D.C.

    1987-11-20

    A porcelain enamel composition as a neutron absorbing material can be prepared of a major proportion by weight of a cadmium compound and a minor proportion of compound of boron, lithium and silicon. These compounds in the form of a porcelain enamel coating or layer on several alloys has been found to be particularly effective in enhancing the nuclear safety of equipment for use in the processing and storage of fissile material. The composition of the porcelain enamel coating can be tailored to match the coefficient of thermal expansion of the equipment to be coated and excellent coating adhesion can be achieved. 2 figs.

  19. Porcelain enamel neutron absorbing material

    DOEpatents

    Iverson, Daniel C.

    1990-01-01

    A porcelain enamel composition as a neutron absorbing material can be prepared of a major proportion by weight of a cadmium compound and a minor proportion of compounds of boron, lithium and silicon. These compounds in the form of a porcelain enamel coating or layer on several alloys has been found to be particularly effective in enhancing the nuclear safety of equipment for use in the processing and storage of fissile material. The composition of the porcelain enamel coating can be tailored to match the coefficient of thermal expansion of the equipment to be coated and excellent coating adhesion can be achieved.

  20. Constraining MHD Disk-Winds with X-ray Absorbers

    NASA Astrophysics Data System (ADS)

    Fukumura, Keigo; Tombesi, F.; Shrader, C. R.; Kazanas, D.; Contopoulos, J.; Behar, E.

    2014-01-01

    From the state-of-the-art spectroscopic observations of active galactic nuclei (AGNs) the robust features of absorption lines (e.g. most notably by H/He-like ions), called warm absorbers (WAs), have been often detected in soft X-rays (< 2 keV). While the identified WAs are often mildly blueshifted to yield line-of-sight velocities up to ~100-3,000 km/sec in typical X-ray-bright Seyfert 1 AGNs, a fraction of Seyfert galaxies such as PG 1211+143 exhibits even faster absorbers (v/ 0.1-0.2) called ultra-fast outflows (UFOs) whose physical condition is much more extreme compared with the WAs. Motivated by these recent X-ray data we show that the magnetically- driven accretion-disk wind model is a plausible scenario to explain the characteristic property of these X-ray absorbers. As a preliminary case study we demonstrate that the wind model parameters (e.g. viewing angle and wind density) can be constrained by data from PG 1211+143 at a statistically significant level with chi-squared spectral analysis. Our wind models can thus be implemented into the standard analysis package, XSPEC, as a table spectrum model for general analysis of X-ray absorbers.

  1. Testing Asymmetry in Plasma-Ball Growth Seeded by a Nanoscale Absorbing Defect Embedded in a SiO2 Thin-Film Matrix Subjected to UV Pulsed-Laser Radiation

    SciTech Connect

    Papernov, S.; Schmid, A.W.

    2008-09-16

    Previous studies of ultraviolet, nanosecond-pulsed-laser damage in thin films revealed nanoscale absorbing defects as a major source of damage initiation. It was also demonstrated that damage (crater formation) is facilitated by plasma-ball formation around absorbing defects. In this work an attempt is made to verify the symmetry of the plasma ball by irradiating SiO2 thin film with embedded gold nanoparticles from the side of either the air/film or substrate/film interfaces. Crater-formation thresholds derived in each case support preferential plasma-ball growth in the direction of the laser-beam source. The strong impact of internal E-field distribution is identified.

  2. Testing asymmetry in plasma-ball growth seeded by a nanoscale absorbing defect embedded in a SiO{sub 2} thin-film matrix subjected to UV pulsed-laser radiation

    SciTech Connect

    Papernov, S.; Schmid, A. W.

    2008-09-15

    Previous studies of ultraviolet, nanosecond-pulsed-laser damage in thin films revealed nanoscale absorbing defects as a major source of damage initiation. It was also demonstrated that damage (crater formation) is facilitated by plasma-ball formation around absorbing defects. In this work an attempt is made to verify the symmetry of the plasma ball by irradiating SiO{sub 2} thin film with embedded gold nanoparticles from the side of either the air/film or substrate/film interfaces. Crater-formation thresholds derived in each case support preferential plasma-ball growth in the direction of the laser-beam source. The strong impact of internal E-field distribution is identified.

  3. Fractional vector calculus and fractional Maxwell's equations

    SciTech Connect

    Tarasov, Vasily E.

    2008-11-15

    The theory of derivatives and integrals of non-integer order goes back to Leibniz, Liouville, Grunwald, Letnikov and Riemann. The history of fractional vector calculus (FVC) has only 10 years. The main approaches to formulate a FVC, which are used in the physics during the past few years, will be briefly described in this paper. We solve some problems of consistent formulations of FVC by using a fractional generalization of the Fundamental Theorem of Calculus. We define the differential and integral vector operations. The fractional Green's, Stokes' and Gauss's theorems are formulated. The proofs of these theorems are realized for simplest regions. A fractional generalization of exterior differential calculus of differential forms is discussed. Fractional nonlocal Maxwell's equations and the corresponding fractional wave equations are considered.

  4. Removal of fluorescence and ultraviolet absorbance of dissolved organic matter in reclaimed water by solar light.

    PubMed

    Wu, Qianyuan; Li, Chao; Wang, Wenlong; He, Tao; Hu, Hongying; Du, Ye; Wang, Ting

    2016-05-01

    Storing reclaimed water in lakes is a widely used method of accommodating changes in the consumption of reclaimed water during wastewater reclamation and reuse. Solar light serves as an important function in degrading pollutants during storage, and its effect on dissolved organic matter (DOM) was investigated in this study. Solar light significantly decreased the UV254 absorbance and fluorescence (FLU) intensity of reclaimed water. However, its effect on the dissolved organic carbon (DOC) value of reclaimed water was very limited. The decrease in the UV254 absorbance intensity and FLU excitation-emission matrix regional integration volume (FLU volume) of reclaimed water during solar light irradiation was fit with pseudo-first order reaction kinetics. The decrease of UV254 absorbance was much slower than that of the FLU volume. Ultraviolet light in solar light had a key role in decreasing the UV254 absorbance and FLU intensity during solar light irradiation. The light fluence-based removal kinetic constants of the UV254 and FLU intensity were independent of light intensity. The peaks of the UV254 absorbance and FLU intensity with an apparent molecular weight (AMW) of 100Da to 2000Da decreased after solar irradiation, whereas the DOC value of the major peaks did not significantly change. PMID:27155416

  5. Self-assembly of highly efficient, broadband plasmonic absorbers for solar steam generation

    PubMed Central

    Zhou, Lin; Tan, Yingling; Ji, Dengxin; Zhu, Bin; Zhang, Pei; Xu, Jun; Gan, Qiaoqiang; Yu, Zongfu; Zhu, Jia

    2016-01-01

    The study of ideal absorbers, which can efficiently absorb light over a broad range of wavelengths, is of fundamental importance, as well as critical for many applications from solar steam generation and thermophotovoltaics to light/thermal detectors. As a result of recent advances in plasmonics, plasmonic absorbers have attracted a lot of attention. However, the performance and scalability of these absorbers, predominantly fabricated by the top-down approach, need to be further improved to enable widespread applications. We report a plasmonic absorber which can enable an average measured absorbance of ~99% across the wavelengths from 400 nm to 10 μm, the most efficient and broadband plasmonic absorber reported to date. The absorber is fabricated through self-assembly of metallic nanoparticles onto a nanoporous template by a one-step deposition process. Because of its efficient light absorption, strong field enhancement, and porous structures, which together enable not only efficient solar absorption but also significant local heating and continuous stream flow, plasmonic absorber–based solar steam generation has over 90% efficiency under solar irradiation of only 4-sun intensity (4 kW m−2). The pronounced light absorption effect coupled with the high-throughput self-assembly process could lead toward large-scale manufacturing of other nanophotonic structures and devices. PMID:27152335

  6. UV-B absorbance and UV-B absorbing compounds (para-coumaric acid) in pollen and sporopollenin: the perspective to track historic UV-B levels.

    PubMed

    Rozema, J; Broekman, R A; Blokker, P; Meijkamp, B B; de Bakker, N; van de Staaij, J; van Beem, A; Ariese, F; Kars, S M

    2001-09-01

    UV-B absorbance and UV-B absorbing compounds (UACs) of the pollen of Vicia faba, Betula pendula, Helleborus foetidus and Pinus sylvestris were studied. Sequential extraction demonstrated considerable UV-B absorbance both in the soluble (acid methanol) and insoluble sporopollenin (acetolysis resistant residue) fractions of UACs, while the wall-bound fraction of UACs was small. The UV-B absorbance of the soluble and sporopollenin fraction of pollen of Vicia faba plants exposed to enhanced UV-B (10 kJ m(-2) day(-1) UV-B(BE)) was higher than that of plants that received 0 kJ m(-2) day(-1) UV-B(BB). Pyrolysis gas chromatography-mass spectrometry (py-GC-MS) analysis of pollen demonstrated that p-coumaric acid and ferulic acid formed part of the sporopollenin fraction of the pollen. The amount of these aromatic monomers in the sporopollenin of Vicia faba appeared to increase in response to enhanced UV-B (10 kJ m(-2) day(-1) UV-B(BE)). The detection limit of pyGC-MS was sufficiently low to quantify these phenolic acids in ten pollen grains of Betula and Pinus. The experimental data presented provide evidence for the possibility that polyphenolic compounds in pollen of plants are indicators of solar UV-B and may be applied as a new proxy for the reconstruction of historic variation in solar UV-B levels. PMID:11693361

  7. RERTR-13 Irradiation Summary Report

    SciTech Connect

    D. M. Perez; M. A. Lillo; G. S. Chang; D. M. Wachs; G. A. Roth; N. E. Woolstenhulme

    2012-09-01

    The Reduced Enrichment for Research and Test Reactor (RERTR) experiment RERTR-13 was designed to assess performance of different types of neutron absorbers that can be potentially used as burnable poisons in the low enriched uranium-molybdenum based dispersion and monolithic fuels.1 The following report summarizes the life of the RERTR-13 experiment through end of irradiation, including as-run neutronic analysis results, thermal analysis results and hydraulic testing results.

  8. The Double Absorbing Boundary method

    NASA Astrophysics Data System (ADS)

    Hagstrom, Thomas; Givoli, Dan; Rabinovich, Daniel; Bielak, Jacobo

    2014-02-01

    A new approach is devised for solving wave problems in unbounded domains. It has common features to each of two types of existing techniques: local high-order Absorbing Boundary Conditions (ABC) and Perfectly Matched Layers (PML). However, it is different from both and enjoys relative advantages with respect to both. The new method, called the Double Absorbing Boundary (DAB) method, is based on truncating the unbounded domain to produce a finite computational domain Ω, and on applying a local high-order ABC on two parallel artificial boundaries, which are a small distance apart, and thus form a thin non-reflecting layer. Auxiliary variables are defined on the two boundaries and inside the layer bounded by them, and participate in the numerical scheme. The DAB method is first introduced in general terms, using the 2D scalar time-dependent wave equation as a model. Then it is applied to the 1D Klein-Gordon equation, using finite difference discretization in space and time, and to the 2D wave equation in a wave guide, using finite element discretization in space and dissipative time stepping. The computational aspects of the method are discussed, and numerical experiments demonstrate its performance.

  9. High Conduction Neutron Absorber to Simulate Fast Reactor Environment in an Existing Test Reactor

    SciTech Connect

    Guillen, Donna; Greenwood, Lawrence R.; Parry, James

    2014-06-22

    A need was determined for a thermal neutron absorbing material that could be cooled in a gas reactor environment without using large amounts of a coolant that would thermalize the neutron flux. A new neutron absorbing material was developed that provided high conduction so a small amount of water would be sufficient for cooling thereby thermalizing the flux as little as possible. An irradiation experiment was performed to assess the effects of radiation and the performance of a new neutron absorbing material. Neutron fluence monitors were placed inside specially fabricated holders within a set of drop-in capsules and irradiated for up to four cycles in the Advanced Test Reactor. Following irradiation, the neutron fluence monitor wires were analyzed by gamma and x-ray spectrometry to determine the activities of the activation products. The adjusted neutron fluences were calculated and grouped into three bins – thermal, epithermal and fast to evaluate the spectral shift created by the new material. Fluence monitors were evaluated after four different irradiation periods to evaluate the effects of burn-up in the absorbing material. Additionally, activities of the three highest activity isotopes present in the specimens are given.

  10. Multi-institutional Feasibility Study of a Fast Patient Localization Method in Total Marrow Irradiation With Helical Tomotherapy: A Global Health Initiative by the International Consortium of Total Marrow Irradiation

    PubMed Central

    Takahashi, Yutaka; Vagge, Stefano; Agostinelli, Stefano; Han, Eunyoung; Matulewicz, Lukasz; Schubert, Kai; Chityala, Ravishankar; Ratanatharathorn, Vaneerat; Tournel, Koen; Penagaricano, Jose A.; Florian, Sterzing; Mahe, Marc-Andre; Verneris, Michael R.; Weisdorf, Daniel J.; Corvo, Renzo; Dusenbery, Kathryn E.; Storme, Guy; Hui, Susanta K.

    2014-01-01

    Purpose To develop, characterize, and implement a fast patient localization method for total marrow irradiation. Methods and Materials Topographic images were acquired using megavoltage computed tomography (MVCT) detector data by delivering static orthogonal beams while the couch traversed through the gantry. Geometric and detector response corrections were performed to generate a megavoltage topogram (MVtopo). We also generated kilovoltage topograms (kVtopo) from the projection data of 3-dimensional CT images to reproduce the same geometry as helical tomotherapy. The MVtopo imaging dose and the optimal image acquisition parameters were investigated. A multi-institutional phantom study was performed to verify the image registration uncertainty. Forty-five MVtopo images were acquired and analyzed with in-house image registration software. Results The smallest jaw size (front and backup jaws of 0) provided the best image contrast and longitudinal resolution. Couch velocity did not affect the image quality or geometric accuracy. The MVtopo dose was less than the MVCT dose. The image registration uncertainty from the multi-institutional study was within 2.8 mm. In patient localization, the differences in calculated couch shift between the registration with MVtopo-kVtopo and MVCT-kVCT images in lateral, cranial–caudal, and vertical directions were 2.2 ± 1.7 mm, 2.6 ± 1.4 mm, and 2.7 ± 1.1 mm, respectively. The imaging time in MVtopo acquisition at the couch speed of 3 cm/s was <1 minute, compared with ≥15 minutes in MVCT for all patients. Conclusion Whole-body MVtopo imaging could be an effective alternative to time-consuming MVCT for total marrow irradiation patient localization. PMID:25442340

  11. Multi-institutional Feasibility Study of a Fast Patient Localization Method in Total Marrow Irradiation With Helical Tomotherapy: A Global Health Initiative by the International Consortium of Total Marrow Irradiation

    SciTech Connect

    Takahashi, Yutaka; Vagge, Stefano; Agostinelli, Stefano; Han, Eunyoung; Matulewicz, Lukasz; Schubert, Kai; Chityala, Ravishankar; Ratanatharathorn, Vaneerat; Tournel, Koen; Penagaricano, Jose A.; Florian, Sterzing; Mahe, Marc-Andre; Verneris, Michael R.; Weisdorf, Daniel J.; and others

    2015-01-01

    Purpose: To develop, characterize, and implement a fast patient localization method for total marrow irradiation. Methods and Materials: Topographic images were acquired using megavoltage computed tomography (MVCT) detector data by delivering static orthogonal beams while the couch traversed through the gantry. Geometric and detector response corrections were performed to generate a megavoltage topogram (MVtopo). We also generated kilovoltage topograms (kVtopo) from the projection data of 3-dimensional CT images to reproduce the same geometry as helical tomotherapy. The MVtopo imaging dose and the optimal image acquisition parameters were investigated. A multi-institutional phantom study was performed to verify the image registration uncertainty. Forty-five MVtopo images were acquired and analyzed with in-house image registration software. Results: The smallest jaw size (front and backup jaws of 0) provided the best image contrast and longitudinal resolution. Couch velocity did not affect the image quality or geometric accuracy. The MVtopo dose was less than the MVCT dose. The image registration uncertainty from the multi-institutional study was within 2.8 mm. In patient localization, the differences in calculated couch shift between the registration with MVtopo-kVtopo and MVCT-kVCT images in lateral, cranial–caudal, and vertical directions were 2.2 ± 1.7 mm, 2.6 ± 1.4 mm, and 2.7 ± 1.1 mm, respectively. The imaging time in MVtopo acquisition at the couch speed of 3 cm/s was <1 minute, compared with ≥15 minutes in MVCT for all patients. Conclusion: Whole-body MVtopo imaging could be an effective alternative to time-consuming MVCT for total marrow irradiation patient localization.

  12. Initialized Fractional Calculus

    NASA Technical Reports Server (NTRS)

    Lorenzo, Carl F.; Hartley, Tom T.

    2000-01-01

    This paper demonstrates the need for a nonconstant initialization for the fractional calculus and establishes a basic definition set for the initialized fractional differintegral. This definition set allows the formalization of an initialized fractional calculus. Two basis calculi are considered; the Riemann-Liouville and the Grunwald fractional calculi. Two forms of initialization, terminal and side are developed.

  13. Polymeric near-infrared absorbing dendritic nanogels for efficient in vivo photothermal cancer therapy

    NASA Astrophysics Data System (ADS)

    Molina, Maria; Wedepohl, Stefanie; Calderón, Marcelo

    2016-03-01

    In recent years, several near-infrared light absorbing inorganic nanomaterials have been developed for photothermal therapy. However, their biological fate after injection limits their clinical utilization. In this work, we developed a novel polymeric near-infrared light absorbing material based on a biocompatible thermoresponsive nanogel that is semi-interpenetrated with polyaniline, a conjugated polymer with strong near-infrared absorbance. This polymeric nanocomposite generates heat after being irradiated by NIR light, thereby inducing a local hyperthermia that is used for photothermal cancer therapy in vitro and in vivo.In recent years, several near-infrared light absorbing inorganic nanomaterials have been developed for photothermal therapy. However, their biological fate after injection limits their clinical utilization. In this work, we developed a novel polymeric near-infrared light absorbing material based on a biocompatible thermoresponsive nanogel that is semi-interpenetrated with polyaniline, a conjugated polymer with strong near-infrared absorbance. This polymeric nanocomposite generates heat after being irradiated by NIR light, thereby inducing a local hyperthermia that is used for photothermal cancer therapy in vitro and in vivo. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr07587d

  14. Evaluation of internal alpha-particle radiation exposure and subsequent fertility among a cohort of women formerly employed in the radium dial industry

    SciTech Connect

    Schieve, L.A.; Davis, F.; Freels, S.

    1997-02-01

    This study examined the effect of internal exposure to {alpha}-particle radiation on subsequent fertility among women employed in radium dial industry prior to 1930, when appreciable amounts of radium were often ingested through the practice of pointing the paint brush with the lips. The analysis was limited to women for whom a radium body burden measurement had been obtained and who were married prior to age 45 (n = 603). Internal radiation dose to the ovary was calculated based on initial intakes of radium-226 and radium-228, average ovarian mass, number and energy of {alpha} particles emitted, fraction of energy absorbed within the ovary, effective retention integrals and estimated photon irradiation. Time between marriage and pregnancy, number of pregnancies and number of live births served as surrogates for fertility. Radiation appeared to have no effect on fertility at estimated cumulative ovarian dose equivalents below 5 Sv; above this dose, however, statistically significant declines in both number of pregnancies and live births were observed. These trends persisted after multivariable adjustment for potential confounding variables and after exclusion of subjects contributing a potential classification or selection bias to the study. Additionally, the high-dose group experienced fewer live births than would have been expected based on population rates. There were no differences in time to first pregnancy between high- and low-dose groups. These results are consistent with earlier studies of {gamma}-ray exposures and suggest that exposure to high doses of radiation from internally deposited radium reduces fertility rather than inducing sterility. 42 refs., 5 tabs.

  15. Evaluation of internal alpha radiation exposure and subsequent infertility among a cohort of women formerly employed in the radium dial industry.

    SciTech Connect

    Schieve, L. A.; Davis, F.; Roeske, J.; Handler, A.; Freels, S.; Stinchcomb, T.; Keane, A.; Environmental Research; Univ. of Illinois at Chicago; Univ. of Chicago; DePaul Univ.

    1997-02-01

    This study examined the effect of internal exposure to {alpha}-particle radiation on subsequent fertility among women employed in the radium dial industry prior to 1930, when appreciable amounts of radium were often ingested through the practice of pointing the paint brush with the lips. The analysis was limited to women for whom a radium body burden measurement had been obtained and who were married prior to age 45 (n=603). Internal radiation dose to the ovary was calculated based on initial intakes of radium-226 and radium-228, average ovarian mass, number and energy of {alpha} particles emitted, fraction of energy absorbed with in the ovary, effective retention integrals and estimated photon irradiation. Time between marriage and pregnancy, number of pregnancies and number of live births served as surrogates for fertility. Radiation appeared to have no effect on fertility at estimated cumulative ovarian dose equivalents below 5 Sv; above this dose, however, statistically significant declines in both number of pregnancies and live births were observed. These trends persisted after multivariable adjustment for potential confounding variables and after exclusion of subjects contributing a potential classification or selection bias to the study. Additionally, the high-dose group experienced fewer live births than would have been expected based on population rates. There were no differences in time to first pregnancy between high- and low-dose groups. These results are consistent with earlier studies of {gamma}-ray exposures and suggest that exposure to high doses of radiation from internally deposited radium reduces fertility rather than inducing sterility.

  16. Evaluation of internal alpha-particle radiation exposure and subsequent fertility among a cohort of women formerly employed in the radium dial industry.

    PubMed

    Schieve, L A; Davis, F; Roeske, J; Handler, A; Freels, S; Stinchcomb, T; Keane, A

    1997-02-01

    This study examined the effect of internal exposure to alpha-particle radiation on subsequent fertility among women employed in the radium dial industry prior to 1930, when appreciable amounts of radium were often ingested through the practice of pointing the paint brush with the lips. The analysis was limited to women for whom a radium body burden measurement had been obtained and who were married prior to age 45 (n = 603). Internal radiation dose to the ovary was calculated based on initial intakes of radium-226 and radium-228, average ovarian mass, number and energy of alpha particles emitted, fraction of energy absorbed within the ovary, effective retention integrals and estimated photon irradiation. Time between marriage and pregnancy, number of pregnancies and number of live births served as surrogates for fertility. Radiation appeared to have no effect on fertility at estimated cumulative ovarian dose equivalents below 5 Sv; above this dose, however, statistically significant declines in both number of pregnancies and live births were observed. These trends persisted after multivariable adjustment for potential confounding variables and after exclusion of subjects contributing a potential classification or selection bias to the study. Additionally, the high-dose group experienced fewer live births than would have been expected based on population rates. There were no differences in time to first pregnancy between high- and low-dose groups. These results are consistent with earlier studies of gamma-ray exposures and suggest that exposure to high doses of radiation from internally deposited radium reduces fertility rather than inducing sterility. PMID:9008216

  17. Tempered fractional calculus

    NASA Astrophysics Data System (ADS)

    Sabzikar, Farzad; Meerschaert, Mark M.; Chen, Jinghua

    2015-07-01

    Fractional derivatives and integrals are convolutions with a power law. Multiplying by an exponential factor leads to tempered fractional derivatives and integrals. Tempered fractional diffusion equations, where the usual second derivative in space is replaced by a tempered fractional derivative, govern the limits of random walk models with an exponentially tempered power law jump distribution. The limiting tempered stable probability densities exhibit semi-heavy tails, which are commonly observed in finance. Tempered power law waiting times lead to tempered fractional time derivatives, which have proven useful in geophysics. The tempered fractional derivative or integral of a Brownian motion, called a tempered fractional Brownian motion, can exhibit semi-long range dependence. The increments of this process, called tempered fractional Gaussian noise, provide a useful new stochastic model for wind speed data. A tempered fractional difference forms the basis for numerical methods to solve tempered fractional diffusion equations, and it also provides a useful new correlation model in time series.

  18. Tempered fractional calculus

    SciTech Connect

    Sabzikar, Farzad; Meerschaert, Mark M.; Chen, Jinghua

    2015-07-15

    Fractional derivatives and integrals are convolutions with a power law. Multiplying by an exponential factor leads to tempered fractional derivatives and integrals. Tempered fractional diffusion equations, where the usual second derivative in space is replaced by a tempered fractional derivative, govern the limits of random walk models with an exponentially tempered power law jump distribution. The limiting tempered stable probability densities exhibit semi-heavy tails, which are commonly observed in finance. Tempered power law waiting times lead to tempered fractional time derivatives, which have proven useful in geophysics. The tempered fractional derivative or integral of a Brownian motion, called a tempered fractional Brownian motion, can exhibit semi-long range dependence. The increments of this process, called tempered fractional Gaussian noise, provide a useful new stochastic model for wind speed data. A tempered fractional difference forms the basis for numerical methods to solve tempered fractional diffusion equations, and it also provides a useful new correlation model in time series.

  19. Regional Radiation Pneumonitis After SIRT of a Subcapsular Liver Metastasis: What is the Effect of Direct Beta Irradiation?

    SciTech Connect

    Dobrocky, Tomas; Fuerstner, Markus Klaeser, Bernd; Lopez-Benitez, Ruben; Wälti, Yara Banz; Kara, Levent

    2015-08-15

    We herein present a patient undergoing selective internal radiation therapy with an almost normal lung shunt fraction of 11.5 %, developing histologically proven radiation pneumonitis. Due to a predominance of pulmonary consolidations in the right lower lung and its proximity to a large liver metastases located in the dome of the right liver lobe a Monte Carlo simulation was performed to estimate the effect of direct irradiation of the lung parenchyma. According to our calculations direct irradiation seems negligible and RP is almost exclusively due to ectopic draining of radioactive spheres.

  20. Stromal-epithelial dynamics in response to fractionated radiotherapy

    NASA Astrophysics Data System (ADS)

    Qayyum, Muqeem Abdul

    signaling in post-surgical breast cancer recurrence would be to assist radiation oncologists in designing an improved therapeutic strategy. To relate the parameters of cellular function to therapeutic prescriptions which offer an enhanced clinical outcome would address the lack of knowledge regarding recurrence of disease, tumor control and whether the tumor microenvironment requires more aggressive treatments. In our work to date, we have developed a three-dimensional co-culture model to determine how alternative dose fractionations affect the post-surgical microenvironment. This work suggests that 3-D co-cultures provide the microenvironmental cues needed to reexamine the radiobiological basis underlying radiation therapy. The findings suggest dose escalation to the tumor region may deactivate the reactive stroma, thus minimizing the cancer promoting environment. Large-fraction irradiation may be used to sterilize residual tumor cells and inhibit activation of intracellular transduction pathways that are promoted during the post-surgical wound-healing period. Wound-healing mechanisms are characterized by angiogenesis, fibroplasia, collagen production and granulation tissue formation all of which impact patient prognosis. In fact, tumor dose escalation trials have been proven to reduce local recurrence rates and thus new approaches to partial breast irradiation and tumor bed boosting using external-beam electrons and intensity-modulated radiotherapy (IMRT) techniques are currently under use. These techniques minimize absorbed dose to healthy breast tissues. Treating the residual cancer cells and the reactive stroma that has been stimulated by wound healing requires that we look at the interplay between cell types as well as the mechanical and biochemical factors driving disease. We have discovered that the reason hypofractionation schemes (larger irradiation fractions per day with less total dose) offer therapeutic advantages to some patients could be that it is more

  1. Modeling the Absorbing Aerosol Index

    NASA Technical Reports Server (NTRS)

    Penner, Joyce; Zhang, Sophia

    2003-01-01

    We propose a scheme to model the absorbing aerosol index and improve the biomass carbon inventories by optimizing the difference between TOMS aerosol index (AI) and modeled AI with an inverse model. Two absorbing aerosol types are considered, including biomass carbon and mineral dust. A priori biomass carbon source was generated by Liousse et al [1996]. Mineral dust emission is parameterized according to surface wind and soil moisture using the method developed by Ginoux [2000]. In this initial study, the coupled CCM1 and GRANTOUR model was used to determine the aerosol spatial and temporal distribution. With modeled aerosol concentrations and optical properties, we calculate the radiance at the top of the atmosphere at 340 nm and 380 nm with a radiative transfer model. The contrast of radiance at these two wavelengths will be used to calculate AI. Then we compare the modeled AI with TOMS AI. This paper reports our initial modeling for AI and its comparison with TOMS Nimbus 7 AI. For our follow-on project we will model the global AI with aerosol spatial and temporal distribution recomputed from the IMPACT model and DAO GEOS-1 meteorology fields. Then we will build an inverse model, which applies a Bayesian inverse technique to optimize the agreement of between model and observational data. The inverse model will tune the biomass burning source strength to reduce the difference between modelled AI and TOMS AI. Further simulations with a posteriori biomass carbon sources from the inverse model will be carried out. Results will be compared to available observations such as surface concentration and aerosol optical depth.

  2. Comparisons of Monte Carlo calculations with absorbed dose determinations in flat materials using high-current, energetic electron beams

    NASA Astrophysics Data System (ADS)

    Cleland, Marshall R.; Galloway, Richard A.; Heiss, Arthur H.; Logar, John R.

    2007-08-01

    International standards and guidelines for calibrating high-dose dosimetry systems to be used in industrial radiation processing recommend that dose-rate effects on dosimeters be evaluated under conditions of use. This is important when the irradiation relies on high-current electron accelerators, which usually provide very high dose-rates. However, most dosimeter calibration facilities use low-intensity gamma radiation or low-current electron accelerators, which deliver comparatively low dose-rates. Because of issues of thermal conductivity and response, portable calorimeters cannot be practically used with high-current accelerators, where product conveyor speeds under an electron beam can exceed several meters per second and the calorimeter is not suitable for use with product handling systems. As an alternative, Monte Carlo calculations can give theoretical estimates of the absorbed dose in materials with flat or complex configurations such that the results are independent of dose-rate. Monte Carlo results can then be compared to experimental dose determinations to see whether dose-rate effects in the dosimeters are significant. A Monte Carlo code has been used in this study to calculate the absorbed doses in alanine film dosimeters supported by flat sheets of plywood irradiated with electrons using incident energies extending from 1.0 MeV to 10 MeV with beam currents up to 30 mA. The same process conditions have been used for dose determinations with high-current electron beams using low dose-rate gamma calibrated alanine film dosimeters. The close agreement between these calculations and the dosimeter determinations indicates that the response of this type of dosimeter system is independent of the dose-rate, and provides assurance that Monte Carlo calculations can yield results with sufficient accuracy for many industrial applications.

  3. Absorbed dose measurements and predictions on LDEF

    NASA Technical Reports Server (NTRS)

    Frank, A. L.; Benton, E. V.; Armstrong, T. W.; Colborn, B. L.

    1993-01-01

    The overall radiation environment of the Long Duration Exposure Facility (LDEF) was determined in part through the use of thermoluminescent detectors (TLD's) which were included in several experiments. The results given are from four experiments (A0015 Biostack, M0004 Fiber Optics Data Link, P0004 Seeds in Space, and P0006 Linear Energy Transfer Spectrum Measurement) and represent a large fraction of existing absorbed dose data. The TLD's were located on the leading and the trailing edges and the Earth end of the spacecraft under various shielding depths (0.48 to 15.4 g/sq cm). The measured absorbed doses were found to reflect both directional dependence of incident trapped protons and shielding. At the leading edge, doses ranged from 2.10 to 2.58 Gy under shielding of 2.90 to 1.37 g/sq cm Al equivalent (M0004). At the trailing edge, doses varied from 3.04 to 4.49 Gy under shielding of 11.7 to 3.85 g/sq cm (A0015), doses varied from 2.91 to 6.64 Gy under shielding of 11.1 to 0.48 g/sq cm (P0004), and a dose range of 2.66 to 6.48 Gy was measured under shielding of 15.4 to 0.48 g/sq cm (P0006). At the Earth end of the spacecraft, doses from 2.41 to 3.93 Gy were found under shielding of 10.0 to 1.66 g/sq cm (A0015). The effect of the trapped proton anisotropy was such that the western side of LDEF received more than 2 times the dose of the eastern side at shielding depths of approximately 1 g/sq cm. Calculations utilizing a directional model of trapped proton spectra predict smaller doses than those measured, being about 50 percent of measured values at the trailing edge and Earth end, and about 80 percent near the leading edge.

  4. TEMPERED FRACTIONAL CALCULUS

    PubMed Central

    MEERSCHAERT, MARK M.; SABZIKAR, FARZAD; CHEN, JINGHUA

    2014-01-01

    Fractional derivatives and integrals are convolutions with a power law. Multiplying by an exponential factor leads to tempered fractional derivatives and integrals. Tempered fractional diffusion equations, where the usual second derivative in space is replaced by a tempered fractional derivative, govern the limits of random walk models with an exponentially tempered power law jump distribution. The limiting tempered stable probability densities exhibit semi-heavy tails, which are commonly observed in finance. Tempered power law waiting times lead to tempered fractional time derivatives, which have proven useful in geophysics. The tempered fractional derivative or integral of a Brownian motion, called a tempered fractional Brownian motion, can exhibit semi-long range dependence. The increments of this process, called tempered fractional Gaussian noise, provide a useful new stochastic model for wind speed data. A tempered difference forms the basis for numerical methods to solve tempered fractional diffusion equations, and it also provides a useful new correlation model in time series. PMID:26085690

  5. Fast ionized X-ray absorbers in AGNs

    NASA Astrophysics Data System (ADS)

    Fukumura, K.; Tombesi, F.; Kazanas, D.; Shrader, C.; Behar, E.; Contopoulos, I.

    2016-05-01

    We investigate the physics of the X-ray ionized absorbers often identified as warm absorbers (WAs) and ultra-fast outflows (UFOs) in Seyfert AGNs from spectroscopic studies in the context of magnetically-driven accretion-disk wind scenario. Launched and accelerated by the action of a global magnetic field anchored to an underlying accretion disk around a black hole, outflowing plasma is irradiated and ionized by an AGN radiation field characterized by its spectral energy density (SED). By numerically solving the Grad-Shafranov equation in the magnetohydrodynamic (MHD) framework, the physical property of the magnetized disk-wind is determined by a wind parameter set, which is then incorporated into radiative transfer calculations with xstar photoionization code under heating-cooling equilibrium state to compute the absorber's properties such as column density N_H, line-of-sight (LoS) velocity v, ionization parameter ξ, among others. Assuming that the wind density scales as n ∝ r-1, we calculate theoretical absorption measure distribution (AMD) for various ions seen in AGNs as well as line spectra especially for the Fe Kα absorption feature by focusing on a bright quasar PG 1211+143 as a case study and show the model's plausibility. In this note we demonstrate that the proposed MHD-driven disk-wind scenario is not only consistent with the observed X-ray data, but also help better constrain the underlying nature of the AGN environment in a close proximity to a central engine.

  6. Dummy Run of Quality Assurance Program in a Phase 3 Randomized Trial Investigating the Role of Internal Mammary Lymph Node Irradiation in Breast Cancer Patients: Korean Radiation Oncology Group 08-06 Study

    SciTech Connect

    Chung, Yoonsun; Kim, Jun Won; Shin, Kyung Hwan; Kim, Su Ssan; Ahn, Sung-Ja; Park, Won; Lee, Hyung-Sik; Kim, Dong Won; Lee, Kyu Chan; Suh, Hyun Suk; Kim, Jin Hee; Shin, Hyun Soo; Kim, Yong Bae; Suh, Chang-Ok

    2015-02-01

    Purpose: The Korean Radiation Oncology Group (KROG) 08-06 study protocol allowed radiation therapy (RT) technique to include or exclude breast cancer patients from receiving radiation therapy to the internal mammary lymph node (IMN). The purpose of this study was to assess dosimetric differences between the 2 groups and potential influence on clinical outcome by a dummy run procedure. Methods and Materials: All participating institutions were asked to produce RT plans without irradiation (Arm 1) and with irradiation to the IMN (Arm 2) for 1 breast-conservation treatment case (breast-conserving surgery [BCS]) and 1 mastectomy case (modified radical mastectomy [MRM]) whose computed tomography images were provided. We assessed interinstitutional variations in IMN delineation and evaluated the dose-volume histograms of the IMN and normal organs. A reference IMN was delineated by an expert panel group based on the study guidelines. Also, we analyzed the potential influence of actual dose variation observed in this study on patient survival. Results: Although physicians intended to exclude the IMN within the RT field, the data showed almost 59.0% of the prescribed dose was delivered to the IMN in Arm 1. However, the mean doses covering the IMN in Arm 1 and Arm 2 were significantly different for both cases (P<.001). Due to the probability of overdose in Arm 1, the estimated gain in 7-year disease-free survival rate would be reduced from 10% to 7.9% for BCS cases and 7.1% for MRM cases. The radiation doses to the ipsilateral lung, heart, and coronary artery were lower in Arm 1 than in Arm 2. Conclusions: Although this dummy run study indicated that a substantial dose was delivered to the IMN, even in the nonirradiation group, the dose differences between the 2 groups were statistically significant. However, this dosimetric profile should be studied further with actual patient samples and be taken into consideration when analyzing clinical outcomes according to IMN

  7. FRACTIONAL INTEGRATION TOOLBOX

    PubMed Central

    Marinov, Toma M.; Ramirez, Nelson; Santamaria, Fidel

    2014-01-01

    The problems formulated in the fractional calculus framework often require numerical fractional integration/differentiation of large data sets. Several existing fractional control toolboxes are capable of performing fractional calculus operations, however, none of them can efficiently perform numerical integration on multiple large data sequences. We developed a Fractional Integration Toolbox (FIT), which efficiently performs fractional numerical integration/differentiation of the Riemann-Liouville type on large data sequences. The toolbox allows parallelization and is designed to be deployed on both CPU and GPU platforms. PMID:24812536

  8. The impact of absorbed photons on antimicrobial photodynamic efficacy.

    PubMed

    Cieplik, Fabian; Pummer, Andreas; Regensburger, Johannes; Hiller, Karl-Anton; Späth, Andreas; Tabenski, Laura; Buchalla, Wolfgang; Maisch, Tim

    2015-01-01

    Due to increasing resistance of pathogens toward standard antimicrobial procedures, alternative approaches that are capable of inactivating pathogens are necessary in support of regular modalities. In this instance, the photodynamic inactivation of bacteria (PIB) may be a promising alternative. For clinical application of PIB it is essential to ensure appropriate comparison of given photosensitizer (PS)-light source systems, which is complicated by distinct absorption and emission characteristics of given PS and their corresponding light sources, respectively. Consequently, in the present study two strategies for adjustment of irradiation parameters were evaluated: (i) matching energy doses applied by respective light sources (common practice) and (ii) by development and application of a formula for adjusting the numbers of photons absorbed by PS upon irradiation by their corresponding light sources. Since according to the photodynamic principle one PS molecule is excited by the absorption of one photon, this formula allows comparison of photodynamic efficacy of distinct PS per excited molecule. In light of this, the antimicrobial photodynamic efficacy of recently developed PS SAPYR was compared to that of clinical standard PS Methylene Blue (MB) regarding inactivation of monospecies biofilms formed by Enterococcus faecalis and Actinomyces naeslundii whereby evaluating both adjustment strategies. PIB with SAPYR exhibited CFU-reductions of 5.1 log10 and 6.5 log10 against E. faecalis and A. naeslundii, respectively, which is declared as a disinfectant efficacy. In contrast, the effect of PIB with MB was smaller when the applied energy dose was adjusted compared to SAPYR (CFU-reductions of 3.4 log10 and 4.2 log10 against E. faecalis and A. naeslundii), or there was even no effect at all when the number of absorbed photons was adjusted compared to SAPYR. Since adjusting the numbers of absorbed photons is the more precise and adequate method from a photophysical point

  9. The impact of absorbed photons on antimicrobial photodynamic efficacy

    PubMed Central

    Cieplik, Fabian; Pummer, Andreas; Regensburger, Johannes; Hiller, Karl-Anton; Späth, Andreas; Tabenski, Laura; Buchalla, Wolfgang; Maisch, Tim

    2015-01-01

    Due to increasing resistance of pathogens toward standard antimicrobial procedures, alternative approaches that are capable of inactivating pathogens are necessary in support of regular modalities. In this instance, the photodynamic inactivation of bacteria (PIB) may be a promising alternative. For clinical application of PIB it is essential to ensure appropriate comparison of given photosensitizer (PS)-light source systems, which is complicated by distinct absorption and emission characteristics of given PS and their corresponding light sources, respectively. Consequently, in the present study two strategies for adjustment of irradiation parameters were evaluated: (i) matching energy doses applied by respective light sources (common practice) and (ii) by development and application of a formula for adjusting the numbers of photons absorbed by PS upon irradiation by their corresponding light sources. Since according to the photodynamic principle one PS molecule is excited by the absorption of one photon, this formula allows comparison of photodynamic efficacy of distinct PS per excited molecule. In light of this, the antimicrobial photodynamic efficacy of recently developed PS SAPYR was compared to that of clinical standard PS Methylene Blue (MB) regarding inactivation of monospecies biofilms formed by Enterococcus faecalis and Actinomyces naeslundii whereby evaluating both adjustment strategies. PIB with SAPYR exhibited CFU-reductions of 5.1 log10 and 6.5 log10 against E. faecalis and A. naeslundii, respectively, which is declared as a disinfectant efficacy. In contrast, the effect of PIB with MB was smaller when the applied energy dose was adjusted compared to SAPYR (CFU-reductions of 3.4 log10 and 4.2 log10 against E. faecalis and A. naeslundii), or there was even no effect at all when the number of absorbed photons was adjusted compared to SAPYR. Since adjusting the numbers of absorbed photons is the more precise and adequate method from a photophysical point

  10. Recovery of spermatogenesis following pelvic irradiation for Hodgkin's disease.

    PubMed

    Pedrick, T J; Hoppe, R T

    1986-01-01

    Spermatogenesis of 18 male patients who underwent pelvic irradiation for Hodgkin's disease was assessed. All patients had supplemental testicular shielding to limit the testicular dose. The total calculated gonadal dose ranged from 28 to 135 rad, delivered in 22 to 29 fractions, whereas the adjacent lymph nodes were treated to 3750-4500 rad. Sperm concentration of 20 million per ml or greater was considered fertile. Oligospermic and azoospermic determinations were considered subfertile. Whereas only one of six patients (17%) was fertile when tested less than 18 months following pelvic radiotherapy, four of six (66%) were fertile when tested between 18 and 26 months following therapy. Seven of eight patients (88%) were fertile when tested more than 26 mo following completion of treatment. The results are compared to other reports in the literature. Our data support the concept of a time-dependent recovery of spermatogenesis following irradiation. The observed relatively short duration of temporary sterilization should encourage the use of meticulous pelvic shielding, including supplemental testicular shielding to minimize the absorbed gonadal dose. PMID:3943983

  11. Magnetic field effects on microwave absorbing materials

    NASA Technical Reports Server (NTRS)

    Goldberg, Ira; Hollingsworth, Charles S.; Mckinney, Ted M.

    1991-01-01

    The objective of this program was to gather information to formulate a microwave absorber that can work in the presence of strong constant direct current (DC) magnetic fields. The program was conducted in four steps. The first step was to investigate the electrical and magnetic properties of magnetic and ferrite microwave absorbers in the presence of strong magnetic fields. This included both experimental measurements and a literature survey of properties that may be applicable to finding an appropriate absorbing material. The second step was to identify those material properties that will produce desirable absorptive properties in the presence of intense magnetic fields and determine the range of magnetic field in which the absorbers remain effective. The third step was to establish ferrite absorber designs that will produce low reflection and adequate absorption in the presence of intense inhomogeneous static magnetic fields. The fourth and final step was to prepare and test samples of such magnetic microwave absorbers if such designs seem practical.

  12. Active diaphragm rupture with laser beam irradiation

    NASA Astrophysics Data System (ADS)

    Takahashi, T.; Torikai, H.; Yang, Q. S.; Watanabe, K.; Sasoh, A.

    We performed shock tube operations with a layer of diaphragm being ruptured by laser beam irradiation. Mylar or Cellophane was examined as the diaphragm material. It has been demonstrated that shock tube can be operated with this new technique. The absorbed energy depends on the material and thickness of the diaphragm and is an important control parameter.

  13. Direct absorbed dose to water determination based on water calorimetry in scanning proton beam delivery

    SciTech Connect

    Sarfehnia, A.; Clasie, B.; Chung, E.; Lu, H. M.; Flanz, J.; Cascio, E.; Engelsman, M.; Paganetti, H.; Seuntjens, J.

    2010-07-15

    Purpose: The aim of this manuscript is to describe the direct measurement of absolute absorbed dose to water in a scanned proton radiotherapy beam using a water calorimeter primary standard. Methods: The McGill water calorimeter, which has been validated in photon and electron beams as well as in HDR {sup 192}Ir brachytherapy, was used to measure the absorbed dose to water in double scattering and scanning proton irradiations. The measurements were made at the Massachusetts General Hospital proton radiotherapy facility. The correction factors in water calorimetry were numerically calculated and various parameters affecting their magnitude and uncertainty were studied. The absorbed dose to water was compared to that obtained using an Exradin T1 Chamber based on the IAEA TRS-398 protocol. Results: The overall 1-sigma uncertainty on absorbed dose to water amounts to 0.4% and 0.6% in scattered and scanned proton water calorimetry, respectively. This compares to an overall uncertainty of 1.9% for currently accepted IAEA TRS-398 reference absorbed dose measurement protocol. The absorbed dose from water calorimetry agrees with the results from TRS-398 well to within 1-sigma uncertainty. Conclusions: This work demonstrates that a primary absorbed dose standard based on water calorimetry is feasible in scattered and scanned proton beams.

  14. Advanced absorber assembly design for breeder reactors

    SciTech Connect

    Pitner, A.L.; Birney, K.R.

    1980-01-01

    An advanced absorber assembly design has been developed for breeder reactor control rod applications that provides for improved in-reactor performance, longer lifetimes, and reduced fabrication costs. The design comprises 19 vented pins arranged in a circular array inside of round duct tubes. The absorber material is boron carbide; cladding and duct components are constructed from the modified Type 316 stainless steel alloy. Analyses indicate that this design will scram 30 to 40% faster than the reference FFTF absorber assembly. The basic design characteristics of this advanced FFTF absorber assembly are applicable to large core breeder reactor design concepts.

  15. Absorbent product and articles made therefrom

    NASA Technical Reports Server (NTRS)

    Dawn, F. S.; Correale, J. V. (Inventor)

    1982-01-01

    A multilayer absorbent product for use in contact with the skin to absorb fluids is described. The product has a water pervious facing layer for contacting the skin, and a first fibrous wicking layer overlaying the water pervious layer. A first container section is defined by inner and outer layers of a water pervious wicking material in between a first absorbent mass and a second container section defined by inner and outer layers of a water pervious wicking material between what is disposed a second absorbent mass, and a liquid impermeable/gas permeable layer overlaying the second fibrous wicking layer.

  16. TPX/TFTR Neutral Beam energy absorbers

    SciTech Connect

    Dahlgren, F.; Wright, K.; Kamperschroer, J.; Grisham, L.; Lontai, L.; Peters, C.; VonHalle, A.

    1993-11-01

    The present beam energy absorbing surfaces on the TFTR Neutral Beams such as Ion Dumps, Calorimeters, beam defining apertures, and scrapers, are simple water cooled copper plates which wee designed to absorb (via their thermal inertia) the incident beam power for two seconds with a five minute coal down interval between pulses. These components are not capable of absorbing the anticipated beam power loading for 1000 second TPX pulses and will have to be replaced with an actively cooled design. While several actively cooled energy absorbing designs were considered,, the hypervapotron elements currently being used on the JET beamlines were chosen due to their lower cooling water demands and reliable performance on JET.

  17. Advanced Reflector and Absorber Materials (Fact Sheet)

    SciTech Connect

    Not Available

    2010-08-01

    Fact sheet describing NREL CSP Program capabilities in the area of advanced reflector and absorber materials: evaluating performance, determining degradation rates and lifetime, and developing new coatings.

  18. Differential Gene Expression Profiles of Radioresistant Non-Small-Cell Lung Cancer Cell Lines Established by Fractionated Irradiation: Tumor Protein p53-Inducible Protein 3 Confers Sensitivity to Ionizing Radiation

    SciTech Connect

    Lee, Young Sook; Oh, Jung-Hwa; Yoon, Seokjoo; Kwon, Myung-Sang

    2010-07-01

    Purpose: Despite the widespread use of radiotherapy as a local and regional modality for the treatment of cancer, some non-small-cell lung cancers commonly develop resistance to radiation. We thus sought to clarify the molecular mechanisms underlying resistance to radiation. Methods and Materials: We established the radioresistant cell line H460R from radiosensitive parental H460 cells. To identify the radioresistance-related genes, we performed microarray analysis and selected several candidate genes. Results: Clonogenic and MTT assays showed that H460R was 10-fold more resistant to radiation than H460. Microarray analysis indicated that the expression levels of 1,463 genes were altered more than 1.5-fold in H460R compared with parental H460. To evaluate the putative functional role, we selected one interesting gene tumor protein p53-inducible protein 3 (TP53I3), because that this gene was significantly downregulated in radioresistant H460R cells and that it was predicted to link p53-dependent cell death signaling. Interestingly, messenger ribonucleic acid expression of TP53I3 differed in X-ray-irradiated H460 and H460R cells, and overexpression of TP53I3 significantly affected the cellular radiosensitivity of H460R cells. Conclusions: These results show that H460R may be useful in searching for candidate genes that are responsible for radioresistance and elucidating the molecular mechanism of radioresistance.

  19. DIY Fraction Pack.

    ERIC Educational Resources Information Center

    Graham, Alan; Graham, Louise

    2003-01-01

    Describes a very successful attempt to teach fractions to year 5 pupils based on pupils making their own fraction pack. Children decided for themselves how to make the fractional slices used in the activity using colored cardboard sheets and templates of a paper circle consisting of 24 equal slices. (Author/NB)

  20. Device for absorbing mechanical shock

    DOEpatents

    Newlon, C.E.

    1979-08-29

    This invention is a comparatively inexpensive but efficient shock-absorbing device having special application to the protection of shipping and storage cylinders. In a typical application, two of the devices are strapped to a cylinder to serve as saddle-type supports for the cylinder during storage and to protect the cylinder in the event it is dropped during lifting or lowering operations. In its preferred form, the invention includes a hardwood plank whose grain runs in the longitudinal direction. The basal portion of the plank is of solid cross-section, whereas the upper face of the plank is cut away to form a concave surface fittable against the sidewall of a storage cylinder. The concave surface is divided into a series of segments by transversely extending, throughgoing relief slots. A layer of elastomeric material is positioned on the concave face, the elastomer being extrudable into slots when pressed against the segments by a preselected pressure characteristic of a high-energy impact. The compressive, tensile, and shear properties of the hardwood and the elastomer are utilized in combination to provide a surprisingly high energy-absorption capability.

  1. Device for absorbing mechanical shock

    DOEpatents

    Newlon, Charles E.

    1980-01-01

    This invention is a comparatively inexpensive but efficient shock-absorbing device having special application to the protection of shipping and storage cylinders. In a typical application, two of the devices are strapped to a cylinder to serve as saddle-type supports for the cylinder during storage and to protect the cylinder in the event it is dropped during lifting or lowering operations. In its preferred form, the invention includes a hardwood plank whose grain runs in the longitudinal direction. The basal portion of the plank is of solid cross-section, whereas the upper face of the plank is cut away to form a concave surface fittable against the sidewall of a storage cylinder. The concave surface is divided into a series of segments by transversely extending, throughgoing relief slots. A layer of elastomeric material is positioned on the concave face, the elastomer being extrudable into slots when pressed against the segments by a preselected pressure characteristic of a high-energy impact. The compressive, tensile, and shear properties of the hardwood and the elastomer are utilized in combination to provide a surprisingly high energy-absorption capability.

  2. High statistics measurement of the positron fraction in primary cosmic rays of 0.5-500 GeV with the alpha magnetic spectrometer on the international space station.

    PubMed

    Accardo, L; Aguilar, M; Aisa, D; Alpat, B; Alvino, A; Ambrosi, G; Andeen, K; Arruda, L; Attig, N; Azzarello, P; Bachlechner, A; Barao, F; Barrau, A; Barrin, L; Bartoloni, A; Basara, L; Battarbee, M; Battiston, R; Bazo, J; Becker, U; Behlmann, M; Beischer, B; Berdugo, J; Bertucci, B; Bigongiari, G; Bindi, V; Bizzaglia, S; Bizzarri, M; Boella, G; de Boer, W; Bollweg, K; Bonnivard, V; Borgia, B; Borsini, S; Boschini, M J; Bourquin, M; Burger, J; Cadoux, F; Cai, X D; Capell, M; Caroff, S; Carosi, G; Casaus, J; Cascioli, V; Castellini, G; Cernuda, I; Cerreta, D; Cervelli, F; Chae, M J; Chang, Y H; Chen, A I; Chen, H; Cheng, G M; Chen, H S; Cheng, L; Chikanian, A; Chou, H Y; Choumilov, E; Choutko, V; Chung, C H; Cindolo, F; Clark, C; Clavero, R; Coignet, G; Consolandi, C; Contin, A; Corti, C; Coste, B; Cui, Z; Dai, M; Delgado, C; Della Torre, S; Demirköz, M B; Derome, L; Di Falco, S; Di Masso, L; Dimiccoli, F; Díaz, C; von Doetinchem, P; Du, W J; Duranti, M; D'Urso, D; Eline, A; Eppling, F J; Eronen, T; Fan, Y Y; Farnesini, L; Feng, J; Fiandrini, E; Fiasson, A; Finch, E; Fisher, P; Galaktionov, Y; Gallucci, G; García, B; García-López, R; Gast, H; Gebauer, I; Gervasi, M; Ghelfi, A; Gillard, W; Giovacchini, F; Goglov, P; Gong, J; Goy, C; Grabski, V; Grandi, D; Graziani, M; Guandalini, C; Guerri, I; Guo, K H; Haas, D; Habiby, M; Haino, S; Han, K C; He, Z H; Heil, M; Henning, R; Hoffman, J; Hsieh, T H; Huang, Z C; Huh, C; Incagli, M; Ionica, M; Jang, W Y; Jinchi, H; Kanishev, K; Kim, G N; Kim, K S; Kirn, Th; Kossakowski, R; Kounina, O; Kounine, A; Koutsenko, V; Krafczyk, M S; Kunz, S; La Vacca, G; Laudi, E; Laurenti, G; Lazzizzera, I; Lebedev, A; Lee, H T; Lee, S C; Leluc, C; Levi, G; Li, H L; Li, J Q; Li, Q; Li, Q; Li, T X; Li, W; Li, Y; Li, Z H; Li, Z Y; Lim, S; Lin, C H; Lipari, P; Lippert, T; Liu, D; Liu, H; Lolli, M; Lomtadze, T; Lu, M J; Lu, Y S; Luebelsmeyer, K; Luo, F; Luo, J Z; Lv, S S; Majka, R; Malinin, A; Mañá, C; Marín, J; Martin, T; Martínez, G; Masi, N; Massera, F; Maurin, D; Menchaca-Rocha, A; Meng, Q; Mo, D C; Monreal, B; Morescalchi, L; Mott, P; Müller, M; Ni, J Q; Nikonov, N; Nozzoli, F; Nunes, P; Obermeier, A; Oliva, A; Orcinha, M; Palmonari, F; Palomares, C; Paniccia, M; Papi, A; Pauluzzi, M; Pedreschi, E; Pensotti, S; Pereira, R; Pilastrini, R; Pilo, F; Piluso, A; Pizzolotto, C; Plyaskin, V; Pohl, M; Poireau, V; Postaci, E; Putze, A; Quadrani, L; Qi, X M; Rancoita, P G; Rapin, D; Ricol, J S; Rodríguez, I; Rosier-Lees, S; Rossi, L; Rozhkov, A; Rozza, D; Rybka, G; Sagdeev, R; Sandweiss, J; Saouter, P; Sbarra, C; Schael, S; Schmidt, S M; Schuckardt, D; Schulz von Dratzig, A; Schwering, G; Scolieri, G; Seo, E S; Shan, B S; Shan, Y H; Shi, J Y; Shi, X Y; Shi, Y M; Siedenburg, T; Son, D; Spada, F; Spinella, F; Sun, W; Sun, W H; Tacconi, M; Tang, C P; Tang, X W; Tang, Z C; Tao, L; Tescaro, D; Ting, Samuel C C; Ting, S M; Tomassetti, N; Torsti, J; Türkoğlu, C; Urban, T; Vagelli, V; Valente, E; Vannini, C; Valtonen, E; Vaurynovich, S; Vecchi, M; Velasco, M; Vialle, J P; Vitale, V; Volpini, G; Wang, L Q; Wang, Q L; Wang, R S; Wang, X; Wang, Z X; Weng, Z L; Whitman, K; Wienkenhöver, J; Wu, H; Wu, K Y; Xia, X; Xie, M; Xie, S; Xiong, R Q; Xin, G M; Xu, N S; Xu, W; Yan, Q; Yang, J; Yang, M; Ye, Q H; Yi, H; Yu, Y J; Yu, Z Q; Zeissler, S; Zhang, J H; Zhang, M T; Zhang, X B; Zhang, Z; Zheng, Z M; Zhou, F; Zhuang, H L; Zhukov, V; Zichichi, A; Zimmermann, N; Zuccon, P; Zurbach, C

    2014-09-19

    A precision measurement by AMS of the positron fraction in primary cosmic rays in the energy range from 0.5 to 500 GeV based on 10.9 million positron and electron events is presented. This measurement extends the energy range of our previous observation and increases its precision. The new results show, for the first time, that above ∼200  GeV the positron fraction no longer exhibits an increase with energy. PMID:25279616

  3. COBALT-60 Gamma Irradiation of Shrimp.

    NASA Astrophysics Data System (ADS)

    Sullivan, Nancy L. B.

    Meta- and ortho-tyrosine were measured using high performance liquid chromatography (HPLC) in conjunction with electrochemical detection in shrimp irradiated using cobalt-60 gamma radiation in the absorbed dose range 0.8 to 6.0 kGy, in nonirradiated shrimp, and in bovine serum albumin (BSA) irradiated in dilute aqueous solution at 25.0 kGy. Ortho-tyrosine was measured in nonirradiated BSA. Para-, meta-, and ortho-tyrosine were measured using HPLC in conjunction with uv-absorption detection in dilute aqueous solutions of phenylalanine irradiated in the absorbed dose range 16.0 to 195.0 kGy. The measured yields of tyrosine isomers were approximately linear as a function of absorbed dose in shrimp, and in irradiated solutions of phenylalanine up to 37.0 kGy. The occurrence of meta- and ortho-tyrosine, which had formerly been considered unique radiolytic products, has not previously been reported in nonirradiated shrimp or BSA. The conventional hydrolyzation and analytical techniques used in the present study to measure meta- and ortho-tyrosine may provide the basis for a method to detect and determine the dose used in food irradiation.

  4. Cobalt-60 gamma irradiation of shrimp

    SciTech Connect

    Sullivan, N.L.B.

    1993-01-01

    Meta- and ortho-tyrosine were measured using high performance liquid chromatography (HPLC) in conjunction with electrochemical detection in shrimp irradiated using cobalt-60 gamma radiation in the absorbed dose range 0.8 to 6.0 kGy, in nonirradiated shrimp, and in bovine serum albumin (BSA) irradiated in dilute aqueous solution at 25.0 kGy. Ortho-tyrosine was measured in nonirradiated BSA. Para-, meta-, and ortho-tyrosine was measured using HPLC in conjunction with uv-absorption detection in dilute aqueous solutions of phenylalanine irradiated in the absorbed dose range 16.0 to 195.0 kGy. The measured yields of tyrosine isomers were approximately linear as a function of absorbed dose in shrimp, and in irradiated solutions of phenylalanine up to 37.0 kGy. The occurrence of meta- and ortho-tyrosine, which had formerly been considered unique radiolytic products, has not previously been reported in nonirradiated shrimp or BSA. The conventional hydrolyzation and analytical techniques used in the present study to measure meta- and ortho-tyrosine may provide the basis for a method to detect and determine the dose used in food irradiation.

  5. Dysprosium titanate as an absorber material for control rods

    NASA Astrophysics Data System (ADS)

    Risovany, V. D.; Varlashova, E. E.; Suslov, D. N.

    2000-09-01

    Disprosium titanate is an attractive control rod material for the thermal neutron reactors. Its main advantages are: insignificant swelling, no out-gassing under neutron irradiation, rather high neutron efficiency, a high melting point (˜1870°C), non-interaction with the cladding at temperatures above 1000°C, simple fabrication and easily reprocessed non-radioactive waste. It can be used in control rods as pellets and powder. The disprosium titanate control rods have worked off in the MIR reactor for 17 years, in VVER-1000 - for 4 years without any operating problems. After post-irradiation examinations this type of control rod having high lifetime was recommended for the VVER and RBMK. The paper presents the examination results of absorber element dummies containing dysprosium titanate, irradiated in the SM reactor to the neutron fluence of 3.4×10 22 cm -2 ( E>0.1 MeV) and, also, the data on structure, thermal-physical properties of dysprosium titanate, efficiency of dysprosium titanate control rods.

  6. Comments on liquid hydrogen absorbers for MICE

    SciTech Connect

    Green, Michael A.

    2003-02-01

    This report describes the heat transfer problems associatedwith a liquid hydrogen absorber for the MICE experiment. This reportdescribes a technique for modeling heat transfer from the outside world,to the abosrber case and in its vacuum vessel, to the hydrogen and theninto helium gas at 14 K. Also presented are the equation for freeconvection cooling of the liquid hydrogen in the absorber.

  7. [Absorbed doses in dental radiology].

    PubMed

    Bianchi, S D; Roccuzzo, M; Albrito, F; Ragona, R; Anglesio, S

    1996-01-01

    The growing use of dento-maxillo-facial radiographic examinations has been accompanied by the publication of a large number of studies on dosimetry. A thorough review of the literature is presented in this article. Most studies were carried out on tissue equivalent skull phantoms, while only a few were in vivo. The aim of the present study was to evaluate in vivo absorbed doses during Orthopantomography (OPT). Full Mouth Periapical Examination (FMPE) and Intraoral Tube Panoramic Radiography (ITPR). Measurements were made on 30 patients, reproducing clinical conditions, in 46 anatomical sites, with 24 intra- and 22 extra-oral thermoluminiscent dosimeters (TLDS). The highest doses were measured, in orthopantomography, at the right mandibular angle (1899 mu Gy) in FMPE on the right naso-labial fold (5640 mu Gy and in ITPR on the palatal surface of the left second upper molar (1936 mu Gy). Intraoral doses ranged from 21 mu Gy, in orthopantomography, to 4494 mu Gy in FMPE. Standard errors ranged from 142% in ITPR to 5% in orthopantomography. The highest rate of standard errors was found in FMPE and ITPR. The data collected in this trial are in agreement with others in major literature reports. Disagreements are probably due to different exam acquisition and data collections. Such differences, presented comparison in several sites, justify lower doses in FMPE and ITPR. Advantages and disadvantages of in vivo dosimetry of the maxillary region are discussed, the former being a close resemblance to clinical conditions of examination and the latter the impossibility of collecting values in depth of tissues. Finally, both ITPR and FMPE required lower doses than expected, and can be therefore reconsidered relative to their radiation risk. PMID:8966249

  8. Efficient enhancement of internal proton transfer of branched π-extended organic chromophore under one-photon and near-infrared two-photon irradiation

    NASA Astrophysics Data System (ADS)

    Gong, Yulong; Lu, Yao; Ma, Huiying; Ding, Ge; Zhang, Shengtao; Luo, Ziping; Li, Hongru; Gao, Fang

    2015-01-01

    The new branched π-extended conjugated triphenylamine-based organic chromophores bearing with proton transfer segments were synthesized. Internal H-bonding effect in the ground state of these new π-extended chromophores is demonstrated by X-ray single crystal diffraction, 1H NMR spectra and UV-vis spectroscopy. Intramolecular proton transfer in the excited singlet state of the enlarged organic chromophore is greatly increased by the branched structure under one-photo and near-infrared two-photon excitation respectively. The fundamental mechanism of intramolecular proton transfer in the excited state was preliminarily revealed by the potential energy barrier computation of enol-keto phototautomerization.

  9. Intensity and absorbed-power distribution in a cylindrical solar-pumped dye laser

    NASA Technical Reports Server (NTRS)

    Williams, M. D.

    1984-01-01

    The internal intensity and absorbed-power distribution of a simplified hypothetical dye laser of cylindrical geometry is calculated. Total absorbed power is also calculated and compared with laboratory measurements of lasing-threshold energy deposition in a dye cell to determine the suitability of solar radiation as a pump source or, alternatively, what modifications, if any, are necessary to the hypothetical system for solar pumping.

  10. Parasitic oscillation suppression in solid state lasers using absorbing thin films

    DOEpatents

    Zapata, L.E.

    1994-08-02

    A thin absorbing film is bonded onto at least certain surfaces of a solid state laser gain medium. An absorbing metal-dielectric multilayer film is optimized for a broad range of incidence angles, and is resistant to the corrosive/erosive effects of a coolant such as water, used in the forced convection cooling of the film. Parasitic oscillations hamper the operation of solid state lasers by causing the decay of stored energy to amplified rays trapped within the gain medium by total and partial internal reflections off the gain medium facets. Zigzag lasers intended for high average power operation require the ASE absorber. 16 figs.

  11. Parasitic oscillation suppression in solid state lasers using absorbing thin films

    DOEpatents

    Zapata, Luis E.

    1994-01-01

    A thin absorbing film is bonded onto at least certain surfaces of a solid state laser gain medium. An absorbing metal-dielectric multilayer film is optimized for a broad range of incidence angles, and is resistant to the corrosive/erosive effects of a coolant such as water, used in the forced convection cooling of the film. Parasitic oscillations hamper the operation of solid state lasers by causing the decay of stored energy to amplified rays trapped within the gain medium by total and partial internal reflections off the gain medium facets. Zigzag lasers intended for high average power operation require the ASE absorber.

  12. Solar sustained plasma/absorber conceptual design

    NASA Technical Reports Server (NTRS)

    Rodgers, R. J.; Krascella, N. L.; Kendall, J. S.

    1979-01-01

    A space power system concept was evaluated which uses concentrated solar energy to heat a working fluid to temperatures as high as 4000 K. The high temperature working fluid could be used for efficient electric power production in advanced thermal or magnetohydrodynamic conversion cycles. Energy absorber configurations utilizing particles or cesium vapor absorber material were investigaed. Results of detailed radiant heat transfer calculations indicated approximately 86 percent of the incident solar energy could be absorbed within a 12-cm-dia flowing stream of gas borne carbon particles. Calculated total energy absorption in the cesium vapor seeded absorber configuration ranged from 34 percent to 64 percent of the incident solar energy. Solar flux concentration ratios of between approximately 3000 and 10,000 will be required to sustain absorber temperatures in the range from 3000 K to 4000 K.

  13. Gold absorbing film for a composite bolometer

    NASA Technical Reports Server (NTRS)

    Dragovan, M.; Moseley, S. H.

    1984-01-01

    The principles governing the design of metal films are reviewed, with attention also given to the choice of metals. A description is then given of the characteristics of a bolometer with a gold absorbing film. It is demonstrated that gold is effective as an absorbing film for a millimeter bolometer operated at 1.5 K. At 1.5 K, gold is significantly better than bismuth since gold has a lower heat capacity for the absorbing film. At 0.3 K, gold and bismuth are both suitable. It is pointed out that at temperatures below 0.3 K, a superconducting absorbing film can have a heat capacity low enough not to dominate the heat capacity of the detector; for this reason, it may give better performance than a nonsuperconducting absorbing film.

  14. Structured Metal Film as Perfect Absorber

    NASA Astrophysics Data System (ADS)

    Xiong, Xiang; Jiang, Shang-Chi; Peng, Ru-Wen; Wang, Mu

    2014-03-01

    With standing U-shaped resonators, fish-spear-like resonator has been designed for the first time as the building block to assemble perfect absorbers. The samples have been fabricated with two-photon polymerization process and FTIR measurement results support the effectiveness of the perfect absorber design. In such a structure the polarization-dependent resonance occurs between the tines of the spears instead of the conventional design where the resonance occurs between the metallic layers separated by a dielectric interlayer. The incident light neither transmits nor reflects back which results in unit absorbance. The power of light is trapped between the tines of spears and finally be absorbed. The whole structure is covered with a continuous metallic layer with good thermo-conductance, which provides an excellent approach to deal with heat dissipation, is enlightening in exploring metamaterial absorbers.

  15. a Generalized Program for Internal Radionuclide Dosimetry

    NASA Astrophysics Data System (ADS)

    Johnson, Timothy Karl

    The development of monoclonal antibodies specific for tumor surface antigens promises a highly specific carrier medium for delivering a tumorcidal radiation dose. Dosimetry calculations of monoclonal antibodies are made difficult, however, precisely because the focus of radioactivity is targeted for a nonstandard volume in a nonstandard geometry. This precludes straightforward application of the formalism developed for internal radionuclide dosimetry by the Medical Internal Radiation Dose Committee. A software program was written to account for the perturbations introduced by the inclusion of a tumor mass as an additional source of, and target for, radiation. The program allows the interactive development of a mathematical model to account for observed biodistribution data. The model describes the time dependence of radioactivity in each organ system that retains radiolabeled antibody, including tumor. Integration of these "time-activity" curves yield cumulative activity for each organ system identified as a 'source' of radioactivity. A Monte Carlo simulation of photon transport is then executed for each source organ to obtain the fraction of radiation energy absorbed by various 'target' organs. When combined with the cumulative activity, this absorbed fraction allows an estimate of dose to be made for each target organ. The program has been validated against ten analytic models designed to span a range of common input data types. Additionally, a performance benchmark has been defined to assess the practicality of implementing the program on different computing hardware platforms. Sources of error in the computation are elaborated on, and future directions and improvements discussed. The software presents an integrated modeling/dosimetry environment particularly suited for performing Monoclonal Antibody dosimetry. It offers a viable methodology for performing prospective treatment planning, based on extrapolation of tracer kinetic data to therapeutic levels.

  16. [Food irradiation].

    PubMed

    Migdał, W

    1995-01-01

    A worldwide standard on food irradiation was adopted in 1983 by Codex Alimentarius Commission of the Joint Food Standard Programme of the Food and Agriculture Organization (FAO) of the United Nations and the World Health Organization (WHO). As a result, 41 countries have approved the use of irradiation for treating one or more food items and the number is increasing. Generally, irradiation is used to: food loses, food spoilage, disinfestation, safety and hygiene. The number of countries which use irradiation for processing food for commercial purposes has been increasing steadily from 19 in 1987 to 33 today. In the frames of the national programme on the application of irradiation for food preservation and hygienization an experimental plant for electron beam processing has been established in Institute of Nuclear Chemistry and Technology. The plant is equipped with a small research accelerator Pilot (19MeV, 1 kW) and an industrial unit Elektronika (10MeV, 10 kW). On the basis of the research there were performed at different scientific institutions in Poland, health authorities have issued permission for irradiation for: spices, garlic, onions, mushrooms, potatoes, dry mushrooms and vegetables. PMID:8619113

  17. Tissue irradiator

    DOEpatents

    Hungate, F.P.; Riemath, W.F.; Bunnell, L.R.

    1975-12-16

    A tissue irradiator is provided for the in-vivo irradiation of body tissue. The irradiator comprises a radiation source material contained and completely encapsulated within vitreous carbon. An embodiment for use as an in- vivo blood irradiator comprises a cylindrical body having an axial bore therethrough. A radioisotope is contained within a first portion of vitreous carbon cylindrically surrounding the axial bore, and a containment portion of vitreous carbon surrounds the radioisotope containing portion, the two portions of vitreous carbon being integrally formed as a single unit. Connecting means are provided at each end of the cylindrical body to permit connections to blood- carrying vessels and to provide for passage of blood through the bore. In a preferred embodiment, the radioisotope is thulium-170 which is present in the irradiator in the form of thulium oxide. A method of producing the preferred blood irradiator is also provided, whereby nonradioactive thulium-169 is dispersed within a polyfurfuryl alcohol resin which is carbonized and fired to form the integral vitreous carbon body and the device is activated by neutron bombardment of the thulium-169 to produce the beta-emitting thulium-170.

  18. Measurements of the divergence of fast electrons in laser-irradiated spherical targets

    SciTech Connect

    Yaakobi, B.; Solodov, A. A.; Myatt, J. F.; Delettrez, J. A.; Stoeckl, C.; Froula, D. H.

    2013-09-15

    In recent experiments using directly driven spherical targets on the OMEGA laser system, the energy in fast electrons was found to reach ∼1% of the laser energy at an irradiance of ∼1.1 × 10{sup 15} W/cm{sup 2}. The fraction of these fast electrons absorbed in the compressed fuel shell depends on their angular divergence. This paper describes measurements of this divergence deduced from a series of shots where Mo-coated shells of increasing diameter (D) were suspended within an outer CH shell. The intensity of the Mo–Kα line and the hard x-ray radiation were found to increase approximately as ∼D{sup 2}, indicating wide divergence of the fast electrons. Alternative interpretations of these results (electron scattering, radiation excitation of Kα, and an electric field due to return current) are shown to be unimportant.

  19. Investigation of irradiated soil byproducts.

    PubMed

    Brey, R R; Rodriguez, R; Harmon, J F; Winston, P

    2001-01-01

    The high dose irradiation of windblown soil deposited onto the surface of spent nuclear fuel is of concern to long-term fuel storage stability. Such soils could be exposed to radiation fields as great as 1.08 x 10(-3) C/kg-s (15,000 R/hr) during the 40-year anticipated period of interim dry storage prior to placement at the proposed national repository. The total absorbed dose in these cases could be as high as 5 x 10(7) Gy (5 x 10(9) rads). This investigation evaluated the potential generation of explosive or combustible irradiation byproducts during this irradiation. It focuses on the production of radiolytic byproducts generated within the pore water of surrogate clays that are consistent with those found on the Idaho National Engineering and Environmental Laboratory. Synthesized surrogates of localized soils containing combinations of clay, water, and aluminum samples, enclosed within a stainless steel vessel were irradiated and the quantities of the byproducts generated measured. Two types of clays, varying primarily in the presence of iron oxide, were investigated. Two treatment levels of irradiation and a control were investigated. An 18-Mev linear accelerator was used to irradiate samples. The first irradiation level provided an absorbed dose of 3.9 x 10(5)+/-1.4 x 10(5)Gy (3.9 x 10(7)+/-1.4 x 10(7) rads) in a 3-h period. At the second irradiation level, 4.8 x 10(5)+/-2.0 x 10(5)Gy (4.8 x 10(7)+/-2.0 x 10(7) rads) were delivered in a 6-h period. When averaged over all treatment parameters, irradiated clay samples with and without iron (III) oxide (moisture content = 40%) had a production rate of hydrogen gas that was a strong function of radiation-dose. A g-value of 5.61 x 10(-9)+/-1.56 x 10(-9) mol/J (0.054+/-0.015 molecules/100-eV) per mass of pore water was observed in the clay samples without iron (III) oxide for hydrogen gas production. A g-value of 1.07 x 10(-8)+/-2.91 x 10(-9) mol/J (0.103+0.028 molecules/100-eV) per mass of pore water was observed

  20. Melanin pigmented solar absorbing surfaces

    SciTech Connect

    Gallas, J.M.; Eisner, M.

    1980-01-01

    Selectivity enhancement is shown to result for melanin, a black biopolymer pigment, for sufficiently low sample density. The effect is proposed to follow from a consideration of the evanescent waves associated with the total internal reflection phenomenon. A relationship is discussed among powder density, pH and the paramagnetic properties of melanin; this relationship is shown to be consistent with, and offer support to an amino-acid side group proposed earlier as part of the melanin structure. A brief discussion is also presented on the optical properties of melanin and the relative importance of quinhydrone, a change transfer complex believed to exist in the polymeric structure of melanin.

  1. Dividing Fractions: A Pedagogical Technique

    ERIC Educational Resources Information Center

    Lewis, Robert

    2016-01-01

    When dividing one fraction by a second fraction, invert, that is, flip the second fraction, then multiply it by the first fraction. To multiply fractions, simply multiply across the denominators, and multiply across the numerators to get the resultant fraction. So by inverting the division of fractions it is turned into an easy multiplication of…

  2. Application of an internally circulating fluidized bed for windowed solar chemical reactor with direct irradiation of reacting particles - article no. 014504

    SciTech Connect

    Kodama, T.; Enomoto, S.I.; Hatamachi, T.; Gokon, N.

    2008-02-15

    Solar thermochemical processes require the development of a high-temperature solar reactor operating at 1000-1500{sup o}C, such as solar gasification of coal and the thermal reduction of metal oxides as part of a two-step water splitting cycle. Here, we propose to apply 'an internally circulating fluidized bed' for a windowed solar chemical reactor in which reacting particles are directly illuminated. The prototype reactor was constructed in a laboratory scale and demonstrated on CO{sub 2} gasification of coal coke using solar-simulated, concentrated visible light from a sun simulator as the energy source. About 12% of the maximum chemical storage efficiency was obtained by the solar-simulated gasification of the coke.

  3. Oxygen isotope fractionation in double carbonates.

    PubMed

    Zheng, Yong-Fei; Böttcher, Michael E

    2016-01-01

    Oxygen isotope fractionations in double carbonates of different crystal structures were calculated by the increment method. Synthesis experiments were performed at 60 °C and 100 °C to determine oxygen and carbon isotope fractionations involving PbMg[CO3]2. The calculations suggest that the double carbonates of calcite structure are systematically enriched in (18)O relative to those of aragonite and mixture structures. Internally consistent oxygen isotope fractionation factors are obtained for these minerals with respect to quartz, calcite and water at a temperature range of 0-1200 °C. The calculated fractionation factors for double carbonate-water systems are generally consistent with the data available from laboratory experiments. The experimentally determined fractionation factors for PbMg[CO3]2, BaMg[CO3]2 and CaMg[CO3]2 against H2O not only fall between fractionation factors involving pure carbonate end-members but are also close to the calculated fractionation factors. In contrast, experimentally determined carbon isotope fractionation factors between PbMg[CO3]2 and CO2 are much closer to theoretical predictions for the cerussite-CO2 system than for the magnesite-CO2 system, similar to the fractionation behavior for BaMg[CO3]2. Therefore, the combined theoretical and experimental results provide insights into the effects of crystal structure and exchange kinetics on oxygen isotope partitioning in double carbonates. PMID:25393769

  4. Noise-induced absorbing phase transition in a model of opinion formation

    NASA Astrophysics Data System (ADS)

    Vieira, Allan R.; Crokidakis, Nuno

    2016-08-01

    In this work we study a 3-state (+1, -1, 0) opinion model in the presence of noise and disorder. We consider pairwise competitive interactions, with a fraction p of those interactions being negative (disorder). Moreover, there is a noise q that represents the probability of an individual spontaneously change his opinion to the neutral state. Our aim is to study how the increase/decrease of the fraction of neutral agents affects the critical behavior of the system and the evolution of opinions. We derive analytical expressions for the order parameter of the model, as well as for the stationary fraction of each opinion, and we show that there are distinct phase transitions. One is the usual ferro-paramagnetic transition, that is in the Ising universality class. In addition, there are para-absorbing and ferro-absorbing transitions, presenting the directed percolation universality class. Our results are complemented by numerical simulations.

  5. FRACTIONAL PEARSON DIFFUSIONS

    PubMed Central

    Leonenko, Nikolai N.; Meerschaert, Mark M.

    2013-01-01

    Pearson diffusions are governed by diffusion equations with polynomial coefficients. Fractional Pearson diffusions are governed by the corresponding time-fractional diffusion equation. They are useful for modeling sub-diffusive phenomena, caused by particle sticking and trapping. This paper provides explicit strong solutions for fractional Pearson diffusions, using spectral methods. It also presents stochastic solutions, using a non-Markovian inverse stable time change. PMID:23626377

  6. Thin film absorber for a solar collector

    DOEpatents

    Wilhelm, William G.

    1985-01-01

    This invention pertains to energy absorbers for solar collectors, and more particularly to high performance thin film absorbers. The solar collectors comprising the absorber of this invention overcome several problems seen in current systems, such as excessive hardware, high cost and unreliability. In the preferred form, the apparatus features a substantially rigid planar frame with a thin film window bonded to one planar side of the frame. An absorber in accordance with the present invention is comprised of two thin film layers that are sealed perimetrically. In a preferred embodiment, thin film layers are formed from a metal/plastic laminate. The layers define a fluid-tight planar envelope of large surface area to volume through which a heat transfer fluid flows. The absorber is bonded to the other planar side of the frame. The thin film construction of the absorber assures substantially full envelope wetting and thus good efficiency. The window and absorber films stress the frame adding to the overall strength of the collector.

  7. Solar energy absorption by vertical cylindrical-tube absorbers in sunspace enclosures

    SciTech Connect

    McCabe, M.E.; Van Migom, M.

    1983-11-01

    Absorption of radiant solar energy in a building sunspace with a south-facing window and a row of opaque vertical cylindrical-tube solar absorbers is considered. A two-dimensional model is formulated for a horizontal, planar enclosure in which a typical cylindrical absorber tube is subdivided into a number of uniform surface elements and the window and sunspace surfaces are each represented as single elements. Matrix expressions are derived for the radiosity, irradiance, and absorbed solar energy at each surface, considering the transmission of beam and diffuse radiant energy by the window and assuming that all interior surfaces reflect diffusely. The matrix expressions are evaluated for incident solar flux conditions for a south vertical surface on a clear winter day and the results are presented as dimensionless ratios of absorbed-to-incident solar flux as a function of the tube spacing ratio L/R. Hourly values of the spatial distribution of absorbed solar flux are presented for the cylindrical-tube. Space and time averaged values of absorbed solar flux are also presented for the cylinder, the window and the room. The potential application of these results for thermal modeling in passive solar applications is discussed.

  8. The thermal instability of the warm absorber in NGC 3783

    NASA Astrophysics Data System (ADS)

    Goosmann, R. W.; Holczer, T.; Mouchet, M.; Dumont, A.-M.; Behar, E.; Godet, O.; Gonçalves, A. C.; Kaspi, S.

    2016-05-01

    Context. The X-ray absorption spectra of active galactic nuclei frequently show evidence of winds with velocities in the order of 103 km s-1 extending up to 104 km s-1 in the case of ultra-fast outflows. At moderate velocities, these winds are often spectroscopically explained by assuming a number of absorbing clouds along the line of sight. In some cases it was shown that the absorbing clouds are in pressure equilibrium with each other. Aims: We assume a photo-ionized medium with a uniform total (gas+radiation) pressure. The irradiation causes the wind to be radiation pressure compressed (RPC). We attempt to reproduce the observed spectral continuum shape, ionic column densities, and X-ray absorption measure distribution (AMD) of the extensively observed warm absorber in the Seyfert galaxy NGC 3783. Methods: We compare the observational characteristics derived from the 900 ks Chandra observation to radiative transfer computations in pressure equilibrium using the radiative transfer code titan. We explore different values of the ionization parameter ξ of the incident flux and adjust the hydrogen-equivalent column density, NH0, of the warm absorber to match the observed soft X-ray continuum. From the resulting models we derive the column densities for a broad range of ionic species of iron and neon and a theoretical AMD that we compare to the observations. Results: We find an extension of the degeneracy between ξ and NH0 for the constant pressure models previously discussed for NGC 3783. Including the ionic column densities of iron and neon in the comparison between observations and data we conclude that a range of ionization parameters between 4000 and 8000 erg cm s-1 is preferred. For the first time, we present theoretical AMDs for a constant pressure wind in NGC 3783 that correctly reproduces the observed level and is in approximate agreement with the observational appearance of an instability region. Conclusions: Using a variety of observational indicators, we

  9. SU-E-T-511: Do Presage 3D Dosimeters Show Dose Fractionation Sensitivity?

    SciTech Connect

    Klawikowski, S; Alqathami, M; Ibbott, G; Adamovics, J; Benning, R

    2014-06-01

    Purpose: To determine whether Presage 3D polymer dosimeter dose response is sensitive to dose delivery fractionation. Bang gels have demonstrated a dose fractionation related dependence in which a single 400 cGy irradiation would produce a different detector response than four 100 cGy irradiations even if delivered closely in time to one another. Such a fractional dependent response in Presage would be detrimental for measuring multi-beam irradiations. Methods: Two separate batches of Presage were poured into cuvettes, and a third batch was molded into cuvette shaped blocks. A total of 37 cuvettes/blocks were irradiated in a Cobalt-60 irradiator to 400 cGy within solid water phantoms in either one, eight, or sixteen fractions. Another group of 15 cuvettes were also kept unirradiated and used for background subtraction between the pre-scan and post-scan results. The times between fractional deliveries were held constant at 30 seconds and the Cobalt irradiator dose rate was 49 cGy/min. Each Presage batch has a separate dose sensitivity and therefore fractionation response comparisons were only performed within the same batch. The cuvettes were first pre-scanned the day prior to irradiation and post-scanned the day after irradiation. Other than approximately 3 hours warming time prior to each irradiation and optical density measurement the cuvettes were stored in a refrigerator. All cuvettes were stored in a lightless environment throughout manufacturing and testing. The cuvettes’ optical densities were optically measured at 632 nm with a spectrophotometer. Results: No noticeable dose fractionation dependence was detected for any of the three independent batches of Presage for either the eight or sixteen fraction irradiation schemes. Conclusion: These results indicate using Presage 3D dosimeters to measure multi-beam photon irradiations common in IMRT, Gamma Knife, and Cyberknife treatment delivery schemes. Presage dosimeters are made by and trademarked by Heuris

  10. Dynamics of body burdens and doses due to internal irradiation from intakes of long-lived radionuclides by residents of Ozyorsk situated near Mayak PA.

    PubMed

    Suslova, K G; Romanov, S A; Efimov, A V; Sokolova, A B; Sneve, M; Smith, G

    2015-12-01

    This paper presents and discusses new autopsy results and other historic data from earlier autopsies and environmental monitoring linked to releases from the Mayak PA facilities in the Chelyabinsk oblast in the southern Urals. The focus is on residents of the town of Ozyorsk located near to Mayak PA and the dynamics of body burdens and radiation doses from inhalation of plutonium alpha and americium-241, and ingestion of strontium-90 and caesium-137. It is demonstrated that accumulation and exposure from these radionuclides was mainly due to unplanned releases in the 1950s and 60s. The mean content of plutonium alpha at the time of autopsy of people commencing residence in Ozyorsk from 1949 to 1959 was about 3.5 Bq, falling to 0.2 Bq in those arriving after 1990. A reducing trend was also seen for (241)Am. The highest (90)Sr content in Ozyorsk residents was measured in 1967. The (137)Cs body content of residents arriving in Ozyorsk at any time was in almost all cases below the limit of detection. The committed effective dose from internal exposure to these long-lived radionuclides which would have been accumulated in Ozyorsk residents if present from 1949 to 2013 is estimated to be 13 mSv. This dose is primarily attributed to intakes during 1949 to 1959 when the annual effective dose rate was approximately 1 mSv y(-1). The current value is about 0.1 mSv y(-1). This dose is about 20 times higher than the dose from global man-made fallout, which is about 0.005 mSv y(-1) at present, but much lower than that from natural background radiation, i.e. about 2 mSv y(-1). The experience gained from this work and continuing activities can contribute to the development of improved international guidance in legacy situations, particularly as regards the provision and use of monitoring data to test and thereby build confidence in prognostic models for radiation conditions and potential future exposures. The scope includes evidence for the rate of reduction in radionuclide

  11. FTIR analysis of polyethylene terephthalate irradiated by MeV He+

    NASA Astrophysics Data System (ADS)

    Djebara, M.; Stoquert, J. P.; Abdesselam, M.; Muller, D.; Chami, A. C.

    2012-03-01

    The degradation induced by MeV He+ ions onto polyethylene terephthalate (PET) is investigated as a function of fluence and electronic stopping power (dE/dx)e. Stack samples of four 3.6 μm PET films are irradiated by 3.5 MeV He+ under vacuum and room temperature at fluence ranging from 1013 to 1.5 × 1015 He+ cm-2. The entrance energies range from 3.5 MeV for the front film to 0.573 MeV for the rear one at the beginning of the irradiation and the corresponding mean (dE/dx)e lie for pristine PET between 158 and 264 keV/μm. A Fourier transform infrared spectroscopy (FTIR) analysis is undertaken. The different stack films present similar damages with magnitude increase as the fluence goes up. Moreover, higher is the electronic stopping power (dE/dx)e more important is the damage. The evolution of the normalized integrated absorbance A(ϕ)/A0 of the internal reference 1410 cm-1 band as a function of the fluence ϕ presents a complex behavior characterized by a two-exponential decay associated to low and high fluence range. The analysis reveals clearly that the A(ϕ)/A0 of the characteristic benzene ring 1577 cm-1 band remains steady till fluence around 3 × 1014 He+ cm-2 and then decreases smoothly as fluence increases. The band appearing at 1610 cm-1, assigned to mono substituted benzene, presents an integrated absorbance A(ϕ) which rises progressively and levels off beyond a critical fluence around 4 × 1014 He+ cm-2. The cross section of the creation of the monosubstituted benzene lies between 3 × 10-15 and 6 × 10-15 cm2 for (dE/dx)e = 158 and 264 keV/μm, respectively. Drastic loss of crystallinity is induced by the MeV He+ ion irradiation in the polymer. The amorphization is monitored by the evolution of the specific bands of the trans and gauche ethylene glycol residue conformations. A sudden drop in the integrated absorbance of the 1340 cm-1 band which characterizes the trans conformation is observed at fluence around 2 × 1014 He+ cm-2. On the other hand, a

  12. Dosimetry and processing anomalies due to heterogeneities of materials irradiated with high-energy electrons. Influence of heterogeneities on e-irradiation

    NASA Astrophysics Data System (ADS)

    Okuda, Shuichi; Nakamura, Shigeki; Tabata, Tatsuo; Fukuda, Kyue; Seiyama, Takeyoshi; Okabe, Shigeru

    Nonuniform dose distributions in heterogeneous materials irradiated by high-energy electron beams were mapped by using blue cellophane thin dosimeter strip (20μm thickness). The absorbed doses and dose distributions in solid-state dosimeters and in products irradiated for practical use have been estimated from the measurements. Deviations from uniformity of absorbed doses as large as several tens of percent have been found near material interfaces.

  13. Update on meat irradiation

    SciTech Connect

    Olson, D.G.

    1997-12-01

    The irradiation of meat and poultry in the United States is intended to eliminate pathogenic bacteria from raw product, preferably after packaging to prevent recontamination. Irradiation will also increase the shelf life of raw meat and poultry products approximately two to three times the normal shelf life. Current clearances in the United States are for poultry (fresh or frozen) at doses from 1.5 to 3.0 kGy and for fresh pork at doses from 0.3 to 1.0 kGy. A petition for the clearance of all red meat was submitted to the Food and Drug Administration (FDA) in July 1994. The petition is for clearances of fresh meat at doses from 1.5 to 4.5 kGy and for frozen meat at {approximately}2.5 to 7.5 kGy. Clearance for red meat is expected before the end of 1997. There are 28 countries that have food irradiation clearances, of which 18 countries have clearances for meat or poultry. However, there are no uniform categories or approved doses for meat and poultry among the countries that could hamper international trade of irradiated meat and poultry.

  14. Irradiation subassembly

    DOEpatents

    Seim, O.S.; Filewicz, E.C.; Hutter, E.

    1973-10-23

    An irradiation subassembly for use in a nuclear reactor is described which includes a bundle of slender elongated irradiation -capsules or fuel elements enclosed by a coolant tube and having yieldable retaining liner between the irradiation capsules and the coolant tube. For a hexagonal bundle surrounded by a hexagonal tube the yieldable retaining liner may consist either of six segments corresponding to the six sides of the tube or three angular segments each corresponding in two adjacent sides of the tube. The sides of adjacent segments abut and are so cut that metal-tometal contact is retained when the volume enclosed by the retaining liner is varied and Springs are provided for urging the segments toward the center of the tube to hold the capsules in a closely packed configuration. (Official Gazette)

  15. Initiate test loop irradiations of ALSEP process solvent

    SciTech Connect

    Peterman, Dean R.; Olson, Lonnie G.; McDowell, Rocklan G.

    2014-09-01

    This report describes the initial results of the study of the impacts of gamma radiolysis upon the efficacy of the ALSEP process and is written in completion of milestone M3FT-14IN030202. Initial irradiations, up to 100 kGy absorbed dose, of the extraction section of the ALSEP process have been completed. The organic solvent used for these experiments contained 0.05 M TODGA and 0.75 M HEH[EHP] dissolved in n-dodecane. The ALSEP solvent was irradiated while in contact with 3 M nitric acid and the solutions were sparged with compressed air in order to maintain aerated conditions. The irradiated phases were used for the determination of americium and europium distribution ratios as a function of absorbed dose for the extraction and stripping conditions. Analysis of the irradiated phases in order to determine solvent composition as a function of absorbed dose is ongoing. Unfortunately, the failure of analytical equipment necessary for the analysis of the irradiated samples has made the consistent interpretation of the analytical results difficult. Continuing work will include study of the impacts of gamma radiolysis upon the extraction of actinides and lanthanides by the ALSEP solvent and the stripping of the extracted metals from the loaded solvent. The irradiated aqueous and organic phases will be analyzed in order to determine the variation in concentration of solvent components with absorbed gamma dose. Where possible, radiolysis degradation product will be identified.

  16. Estimation of absorbed dose in the covering skin of human melanoma treated by neutron capture therapy

    SciTech Connect

    Fukuda, H.; Kobayashi, T.; Hiratsuka, J.; Karashima, H.; Honda, C.; Yamamura, K.; Ichihashi, M.; Kanda, K.; Mishima, Y. )

    1989-07-01

    A patient with malignant melanoma was treated by thermal neutron capture therapy using 10B-paraboronophenylalanine. The compound was injected subcutaneously into ten locations in the tumor-surrounding skin, and the patient was then irradiated with thermal neutrons from the Musashi Reactor at reactor power of 100 KW and neutron flux of 1.2 X 10(9) n/cm{sup 2}/s. Total absorbed dose to the skin was 11.7-12.5 Gy in the radiation field. The dose equivalents of these doses were estimated as 21.5 and 24.4 Sv, respectively. Early skin reaction after irradiation was checked from day 1 to day 60. The maximum and mean skin scores were 2.0 and 1.5, respectively, and the therapy was safely completed as far as skin reaction was concerned. Some factors influencing the absorbed dose and dose equivalent to the skin are discussed.

  17. An Appetite for Fractions

    ERIC Educational Resources Information Center

    Wilkerson, Trena L.; Bryan, Tommy; Curry, Jane

    2012-01-01

    This article describes how using candy bars as models gives sixth-grade students a taste for learning to represent fractions whose denominators are factors of twelve. Using paper models of the candy bars, students explored and compared fractions. They noticed fewer different representations for one-third than for one-half. The authors conclude…

  18. Can Kindergartners Do Fractions?

    ERIC Educational Resources Information Center

    Cwikla, Julie

    2014-01-01

    Mathematics professor Julie Cwikla decided that she needed to investigate young children's understandings and see what precurricular partitioning notions young minds bring to the fraction table. Cwikla realized that only a handful of studies have examined how preschool-age and early elementary school-age students solve fraction problems…

  19. The Future of Fractions

    ERIC Educational Resources Information Center

    Usiskin, Zalman P.

    2007-01-01

    In the 1970s, the movement to the metric system (which has still not completely occurred in the United States) and the advent of hand-held calculators led some to speculate that decimal representation of numbers would render fractions obsolete. This provocative proposition stimulated Zalman Usiskin to write "The Future of Fractions" in 1979. He…

  20. (Carbon isotope fractionation inplants)

    SciTech Connect

    O'Leary, M.H.

    1990-01-01

    The objectives of this research are: To develop a theoretical and experimental framework for understanding isotope fractionations in plants; and to develop methods for using this isotope fractionation for understanding the dynamics of CO{sub 2} fixation in plants. Progress is described.