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Sample records for high sensitivity radiation

  1. Highly sensitive microcalorimeters for radiation research

    International Nuclear Information System (INIS)

    Avaev, V.N.; Demchuk, B.N.; Ioffe, L.A.; Efimov, E.P.

    1984-01-01

    Calorimetry is used in research at various types of nuclear-physics installations to obtain information on the quantitative and qualitative composition of ionizing radiation in a reactor core and in the surrounding layers of the biological shield. In this paper, the authors examine the characteristics of highly sensitive microcalorimeters with modular semiconductor heat pickups designed for operation in reactor channels. The microcalorimeters have a thin-walled aluminum housing on whose inner surface modular heat pickups are placed radially as shown here. The results of measurements of the temperature dependence of the sensitivity of the microcalorimeters are shown. The results of measuring the sensitivity of a PMK-2 microcalorimeter assembly as a function of integrated neutron flux for three energy intervals and the adsorbed gamma energy are shown. In order to study specimens with different shapes and sizes, microcalorimeters with chambers in the form of cylinders and a parallelepiped were built and tested

  2. High sensitive radiation detector for radiology dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Valente, M.; Malano, F. [Instituto de Fisica Enrique Gaviola, Oficina 102 FaMAF - UNC, Av. Luis Medina Allende, Ciudad Universitaria, 5000 Cordoba (Argentina); Molina, W.; Vedelago, J., E-mail: valente@famac.unc.edu.ar [Laboratorio de Investigaciones e Instrumentacion en Fisica Aplicada a la Medicina e Imagenes por Rayos X, Laboratorio 448 FaMAF - UNC, Ciudad Universitaria, 5000 Cordoba (Argentina)

    2014-08-15

    Fricke solution has a wide range of applications as radiation detector and dosimetry. It is particularly appreciated in terms of relevant comparative advantages, like tissue equivalence when prepared in aqueous media like gel matrix, continuous mapping capability, dose rate recorded and incident direction independence as well as linear dose response. This work presents the development and characterization of a novel Fricke gel system, based on modified chemical compositions making possible its application in clinical radiology. Properties of standard Fricke gel dosimeter for high dose levels are used as starting point and suitable chemical modifications are introduced and carefully investigated in order to attain high resolution for low dose ranges, like those corresponding to radiology interventions. The developed Fricke gel radiation dosimeter system achieves the expected typical dose dependency, actually showing linear response in the dose range from 20 up to 4000 mGy. Systematic investigations including several chemical compositions are carried out in order to obtain a good enough dosimeter response for low dose levels. A suitable composition among those studied is selected as a good candidate for low dose level radiation dosimetry consisting on a modified Fricke solution fixed to a gel matrix containing benzoic acid along with sulfuric acid, ferrous sulfate, xylenol orange and ultra-pure reactive grade water. Dosimeter samples are prepared in standard vials for its in phantom irradiation and further characterization by spectrophotometry measuring visible light transmission and absorbance before and after irradiation. Samples are irradiated by typical kV X-ray tubes and calibrated Farmer type ionization chamber is used as reference to measure dose rates inside phantoms in at vials locations. Once sensitive material composition is already optimized, dose-response curves show significant improvement regarding overall sensitivity for low dose levels. According to

  3. High sensitive radiation detector for radiology dosimetry

    International Nuclear Information System (INIS)

    Valente, M.; Malano, F.; Molina, W.; Vedelago, J.

    2014-08-01

    Fricke solution has a wide range of applications as radiation detector and dosimetry. It is particularly appreciated in terms of relevant comparative advantages, like tissue equivalence when prepared in aqueous media like gel matrix, continuous mapping capability, dose rate recorded and incident direction independence as well as linear dose response. This work presents the development and characterization of a novel Fricke gel system, based on modified chemical compositions making possible its application in clinical radiology. Properties of standard Fricke gel dosimeter for high dose levels are used as starting point and suitable chemical modifications are introduced and carefully investigated in order to attain high resolution for low dose ranges, like those corresponding to radiology interventions. The developed Fricke gel radiation dosimeter system achieves the expected typical dose dependency, actually showing linear response in the dose range from 20 up to 4000 mGy. Systematic investigations including several chemical compositions are carried out in order to obtain a good enough dosimeter response for low dose levels. A suitable composition among those studied is selected as a good candidate for low dose level radiation dosimetry consisting on a modified Fricke solution fixed to a gel matrix containing benzoic acid along with sulfuric acid, ferrous sulfate, xylenol orange and ultra-pure reactive grade water. Dosimeter samples are prepared in standard vials for its in phantom irradiation and further characterization by spectrophotometry measuring visible light transmission and absorbance before and after irradiation. Samples are irradiated by typical kV X-ray tubes and calibrated Farmer type ionization chamber is used as reference to measure dose rates inside phantoms in at vials locations. Once sensitive material composition is already optimized, dose-response curves show significant improvement regarding overall sensitivity for low dose levels. According to

  4. Position sensitive detection of neutrons in high radiation background field.

    Science.gov (United States)

    Vavrik, D; Jakubek, J; Pospisil, S; Vacik, J

    2014-01-01

    We present the development of a high-resolution position sensitive device for detection of slow neutrons in the environment of extremely high γ and e(-) radiation background. We make use of a planar silicon pixelated (pixel size: 55 × 55 μm(2)) spectroscopic Timepix detector adapted for neutron detection utilizing very thin (10)B converter placed onto detector surface. We demonstrate that electromagnetic radiation background can be discriminated from the neutron signal utilizing the fact that each particle type produces characteristic ionization tracks in the pixelated detector. Particular tracks can be distinguished by their 2D shape (in the detector plane) and spectroscopic response using single event analysis. A Cd sheet served as thermal neutron stopper as well as intensive source of gamma rays and energetic electrons. Highly efficient discrimination was successful even at very low neutron to electromagnetic background ratio about 10(-4).

  5. Process for curing ionizing radiation-highly sensitive resin composition

    International Nuclear Information System (INIS)

    Araki, K.; Sasaki, T.; Tabei, K.; Goto, K.

    1979-01-01

    A process is described for curing a radiation curable composition consisting essentially of (a) an amide represented by the formula R,CONR 2 R 3 and (b) an unsaturated polyester resin by irradiating the composition with an ionizing radiation. R 1 is H, an alkyl groups having from 1 to 17 carbon atoms or an alkenyl groups having from 1 to 17 carbon atoms, and R 2 and R 3 are each -H, -CH 3 , or -CH 2 OH. R 1 and R 2 taken together represent alkylene having 2 to 5 carbon atoms

  6. Highly Sensitive Detection of UV Radiation Using a Uranium Coordination Polymer.

    Science.gov (United States)

    Liu, Wei; Dai, Xing; Xie, Jian; Silver, Mark A; Zhang, Duo; Wang, Yanlong; Cai, Yawen; Diwu, Juan; Wang, Jian; Zhou, Ruhong; Chai, Zhifang; Wang, Shuao

    2018-02-07

    The accurate detection of UV radiation is required in a wide range of chemical industries and environmental or biological related applications. Conventional methods taking advantage of semiconductor photodetectors suffer from several drawbacks such as sophisticated synthesis and manufacturing procedure, not being able to measure the accumulated UV dosage as well as high defect density in the material. Searching for new strategies or materials serving as precise UV dosage sensor with extremely low detection limit is still highly desirable. In this work, a radiation resistant uranium coordination polymer [UO 2 (L)(DMF)] (L = 5-nitroisophthalic acid, DMF = N,N-dimethylformamide, denoted as compound 1) was successfully synthesized through mild solvothermal method and investigated as a unique UV probe with the detection limit of 2.4 × 10 -7 J. On the basis of the UV dosage dependent luminescence spectra, EPR analysis, single crystal structure investigation, and the DFT calculation, the UV-induced radical quenching mechanism was confirmed. Importantly, the generated radicals are of significant stability which offers the opportunity for measuring the accumulated UV radiation dosage. Furthermore, the powder material of compound 1 was further upgraded into membrane material without loss in luminescence intensity to investigate the real application potentials. To the best of our knowledge, compound 1 represents the most sensitive coordination polymer based UV dosage probe reported to date.

  7. Using Satellites to Investigate the Sensitivity of Longwave Downward Radiation to Water Vapor at High Elevations

    Science.gov (United States)

    Naud, Catherine M.; Miller, James R.; Landry, Chris

    2012-01-01

    Many studies suggest that high-elevation regions may be among the most sensitive to future climate change. However, in situ observations in these often remote locations are too sparse to determine the feedbacks responsible for enhanced warming rates. One of these feedbacks is associated with the sensitivity of longwave downward radiation (LDR) to changes in water vapor, with the sensitivity being particularly large in many high-elevation regions where the average water vapor is often low. We show that satellite retrievals from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Clouds and the Earth's Radiant Energy System (CERES) can be used to expand the current ground-based observational database and that the monthly averaged clear-sky satellite estimates of humidity and LDR are in good agreement with the well-instrumented Center for Snow and Avalanche Studies ground-based site in the southwestern Colorado Rocky Mountains. The relationship between MODIS-retrieved precipitable water vapor and surface specific humidity across the contiguous United States was found to be similar to that previously found for the Alps. More important, we show that satellites capture the nonlinear relationship between LDR and water vapor and confirm that LDR is especially sensitive to changes in water vapor at high elevations in several midlatitude mountain ranges. Because the global population depends on adequate fresh water, much of which has its source in high mountains, it is critically important to understand how climate will change there. We demonstrate that satellites can be used to investigate these feedbacks in high-elevation regions where the coverage of surface-based observations is insufficient to do so.

  8. Radiation-sensitive diacrylates

    International Nuclear Information System (INIS)

    Demajistre, R.

    1976-01-01

    Novel diacrylates are prepared by reacting a monohydroxylated acrylic monomer with a polyisocyanate. The reaction product may be polymerized by subjecting to ionizing irradiation, actinic light or to free radical catalysts to form a useful coating material. The diacrylates may also be copolymerized with other radiation sensitive materials. 6 claims, no drawings

  9. Targeting DNA repair with PNKP inhibition sensitizes radioresistant prostate cancer cells to high LET radiation.

    Directory of Open Access Journals (Sweden)

    Pallavi Srivastava

    Full Text Available High linear energy transfer (LET radiation or heavy ion such as carbon ion radiation is used as a method for advanced radiotherapy in the treatment of cancer. It has many advantages over the conventional photon based radiotherapy using Co-60 gamma or high energy X-rays from a Linear Accelerator. However, charged particle therapy is very costly. One way to reduce the cost as well as irradiation effects on normal cells is to reduce the dose of radiation by enhancing the radiation sensitivity through the use of a radiomodulator. PNKP (polynucleotide kinase/phosphatase is an enzyme which plays important role in the non-homologous end joining (NHEJ DNA repair pathway. It is expected that inhibition of PNKP activity may enhance the efficacy of the charged particle irradiation in the radioresistant prostate cancer cell line PC-3. To test this hypothesis, we investigated cellular radiosensitivity by clonogenic cell survival assay in PC-3 cells.12Carbon ion beam of62 MeVenergy (equivalent 5.16 MeV/nucleon and with an entrance LET of 287 kev/μm was used for the present study. Apoptotic parameters such as nuclear fragmentation and caspase-3 activity were measured by DAPI staining, nuclear ladder assay and colorimetric caspase-3method. Cell cycle arrest was determined by FACS analysis. Cell death was enhanced when carbon ion irradiation is combined with PNKPi (PNKP inhibitor to treat cells as compared to that seen for PNKPi untreated cells. A low concentration (10μM of PNKPi effectively radiosensitized the PC-3 cells in terms of reduction of dose in achieving the same survival fraction. PC-3 cells underwent significant apoptosis and cell cycle arrest too was enhanced at G2/M phase when carbon ion irradiation was combined with PNKPi treatment. Our findings suggest that combined treatment of carbon ion irradiation and PNKP inhibition could enhance cellular radiosensitivity in a radioresistant prostate cancer cell line PC-3. The synergistic effect of PNKPi

  10. Low and high linear energy transfer radiation sensitization of HCC cells by metformin

    International Nuclear Information System (INIS)

    Kim, Eun Ho; Jung, Won-Gyun; Kim, Mi-Sook; Cho, Chul-Koo; Jeong, Youn Kyoung; Jeong, Jae-Hoon

    2014-01-01

    The purpose of this study was to investigate the efficacy of metformin as a radiosensitizer for use in combination therapy for human hepatocellular carcinoma (HCC). Three human HCC cell lines (Huh7, HepG2, Hep3B) and a normal human hepatocyte cell line were treated with metformin alone or with radiation followed by metformin. In vitro tests were evaluated by clonogenic survival assay, FACS analysis, western blotting, immunofluorescence and comet assay. Metformin significantly enhanced radiation efficacy under high and low Linear Energy Transfer (LET) radiation conditions in vitro. In combination with radiation, metformin abrogated G2/M arrest and increased the cell population in the sub-G1 phase and the ROS level, ultimately increasing HCC cellular apoptosis. Metformin inhibits the repair of DNA damage caused by radiation. The radiosensitizing effects of metformin are much higher in neutron (high LET)-irradiated cell lines than in γ (low LET)-irradiated cell lines. Metformin only had a moderate effect in normal hepatocytes. Metformin enhances the radiosensitivity of HCC, suggesting it may have clinical utility in combination cancer treatment with high-LET radiation. (author)

  11. Irradiation of cells by single and double pulses of high intensity radiation: oxygen sensitization and diffusion kinetics

    International Nuclear Information System (INIS)

    Epp, E.R.; Ling, C.C.; Weiss, H.

    1976-01-01

    This paper discusses advances made on both experimental and theoretical approaches involving single and double pulses of high intensity ionizing radiation delivered to cultured bacterial and mammalian cells where the effect of oxygen is concerned. Information gained on the lifetime of oxygen-sensitive species suspected to be produced in critical molecules in irradiated cells and perhaps intimately related to the still unknown mechanisms of oxygen sensitization is described. The diffusion characteristics of oxygen at the cellular level obtained from experimental data are discussed. Current knowledge on intracellular radiolytic oxygen depletion is also presented. Future work on the use of high intensity pulsed radiation as a tool in cellular radiobiological research is outlined. It is expected that obtaining knowledge of the time available for damaged molecules to enter into chemical reactions may lead to insights into the mechanisms of radiation injury in cells, such as those involved in the oxygen effect. (Auth.)

  12. Using synchrotron radiation angiography with a highly sensitive detector to identify impaired peripheral perfusion in rat pulmonary emphysema

    International Nuclear Information System (INIS)

    Ito, Hiromichi; Matsushita, Shonosuke; Hyodo, Kazuyuki; Sato, Yukio; Sakakibara, Yuzuru

    2013-01-01

    Synchrotron radiation angiography with a HARP detector made it possible to evaluate impaired pulmonary microcirculation in pulmonary emphysema by means of high sensitivity. Owing to limitations in spatial resolution and sensitivity, it is difficult for conventional angiography to detect minute changes of perfusion in diffuse lung diseases, including pulmonary emphysema (PE). However, a high-gain avalanche rushing amorphous photoconductor (HARP) detector can give high sensitivity to synchrotron radiation (SR) angiography. SR angiography with a HARP detector provides high spatial resolution and sensitivity in addition to time resolution owing to its angiographic nature. The purpose of this study was to investigate whether this SR angiography with a HARP detector could evaluate altered microcirculation in PE. Two groups of rats were used: group PE and group C (control). Transvenous SR angiography with a HARP detector was performed and histopathological findings were compared. Peak density of contrast material in peripheral lung was lower in group PE than group C (p < 0.01). The slope of the linear regression line in scattering diagrams was also lower in group PE than C (p < 0.05). The correlation between the slope and extent of PE in histopathology showed significant negative correlation (p < 0.05, r = 0.61). SR angiography with a HARP detector made it possible to identify impaired microcirculation in PE by means of its high spatial resolution and sensitivity

  13. Using synchrotron radiation angiography with a highly sensitive detector to identify impaired peripheral perfusion in rat pulmonary emphysema

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Hiromichi [University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575 (Japan); Matsushita, Shonosuke, E-mail: shomatsu@md.tsukuba.ac.jp [University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575 (Japan); Tsukuba University of Technology, Tsukuba, Ibaraki 305-8521 (Japan); Hyodo, Kazuyuki [High Energy Accelerator Research Organization, KEK, Tsukuba, Ibaraki 305-0801 (Japan); Sato, Yukio; Sakakibara, Yuzuru [University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575 (Japan)

    2013-03-01

    Synchrotron radiation angiography with a HARP detector made it possible to evaluate impaired pulmonary microcirculation in pulmonary emphysema by means of high sensitivity. Owing to limitations in spatial resolution and sensitivity, it is difficult for conventional angiography to detect minute changes of perfusion in diffuse lung diseases, including pulmonary emphysema (PE). However, a high-gain avalanche rushing amorphous photoconductor (HARP) detector can give high sensitivity to synchrotron radiation (SR) angiography. SR angiography with a HARP detector provides high spatial resolution and sensitivity in addition to time resolution owing to its angiographic nature. The purpose of this study was to investigate whether this SR angiography with a HARP detector could evaluate altered microcirculation in PE. Two groups of rats were used: group PE and group C (control). Transvenous SR angiography with a HARP detector was performed and histopathological findings were compared. Peak density of contrast material in peripheral lung was lower in group PE than group C (p < 0.01). The slope of the linear regression line in scattering diagrams was also lower in group PE than C (p < 0.05). The correlation between the slope and extent of PE in histopathology showed significant negative correlation (p < 0.05, r = 0.61). SR angiography with a HARP detector made it possible to identify impaired microcirculation in PE by means of its high spatial resolution and sensitivity.

  14. Polarization sensitive detection of 100 GHz radiation by high mobility field-effect transistors

    International Nuclear Information System (INIS)

    Sakowicz, M.; Lusakowski, J.; Karpierz, K.; Grynberg, M.; Knap, W.; Gwarek, W.

    2008-01-01

    Detection of 100 GHz electromagnetic radiation by a GaAs/AlGaAs high electron mobility field-effect transistor was investigated at 300 K as a function of the angle α between the direction of linear polarization of the radiation and the symmetry axis of the transistor. The angular dependence of the detected signal was found to be A 0 cos 2 (α-α 0 )+C with A 0 , α 0 , and C dependent on the electrical polarization of the transistor gate. This dependence is interpreted as due to excitation of two crossed phase-shifted oscillators. A response of the transistor chip (including bonding wires and the substrate) to 100 GHz radiation was numerically simulated. Results of calculations confirmed experimentally observed dependencies and showed that the two oscillators result from an interplay of 100 GHz currents defined by the transistor impedance together with bonding wires and substrate related modes

  15. Sensitivities in synchrotron radiation TXRF

    International Nuclear Information System (INIS)

    Pianetta, P.; Baur, K.; Brennan, S.

    2000-01-01

    This work describes the progress we achieved at the Stanford Synchrotron Radiation Laboratory (SSRL) in improving the sensitivity for both the transition metals and light elements such as Al and Na. The transition metal work has matured to the point where a facility exists at SSRL in which semiconductor companies are able to perform industrially relevant measurements at state of the art detection limits. This facility features clean wafer handling and automated data acquisition making routine analytical measurements possible. The best sensitivity demonstrated so far is 3.4 E7 atoms/cm 2 for a 5000 second count time corresponding to 7.6 E7 atoms/cm 2 for a standard 1000 second count time. This is more than a factor of 100 better than what can be achieved with conventional TXRF systems. The detection of light elements such as Al and Na is challenging due to the presence of the h stronger Si fluorescence peak. For traditional energy-dispersive detection only the tunability of synchrotron radiation to excitation energies below the Si-K absorption edge leads to an acceptable sensitivity for Al detection which is limited by a large background due to inelastic x-ray Raman scattering. An alternative approach to overcome the Raman contribution and the strong Si fluorescence is to use a wavelength-dispersive spectrometer for fluorescence detection. The benefits of such a multilayer spectrometer over a solid state detector are its higher energy resolution and greater dynamic range. This strategy allows primary excitation above the Si K absorption edge, eliminating the background due to Raman scattering, and a gracing emission geometry to guarantee high surface sensitivity. Studies testing this concept in combination with high flux synchrotron radiation are underway and first results will be presented. (author)

  16. Establishment of cell lines derived from ataxia telangiectasia and xeroderma pigmentosum patients with high radiation sensitivity

    International Nuclear Information System (INIS)

    Hashimoto, Tomoko; Furuyama, Jun-ichi; Nakano, Yoshiro; Owada, M. Koji; Kakunaga, Takeo

    1986-01-01

    Four human fibroblast cell lines, three of which were derived from a patient with ataxia telangiectasia and the other from a patient with xeroderma pigmentosum, were established after transfection with cloned SV40 DNA. These 4 cell lines showed some phenotypes characteristic of neoplastically transformed cells, and had a human karyotype with heteromorphisms identical to those of the parental fibroblasts. Their sensitivity to the cytotoxic effects of γ-rays or ultraviolet irradiation was as high as those of their parental fibroblasts. (Auth.)

  17. Radiation Sensitivity of Societies

    International Nuclear Information System (INIS)

    Uray, I.; Hille, R.; Rohloff, F.

    1998-01-01

    Investigating the mean dose values as well as dose distributions of the inhabitants in a large number of settlements maybe set down, that the generally calculated mean exposure is a good measure to estimate the collective dose for a settlement or for a large region. Its uncertainty is however too high, and the dose distribution is very broad (250-300%) to estimate the external exposure of any single person. However, models may take into account more details of influencing factors. First of all the surveying of the local contamination density distribution could be more detailed and more accurate. Measure and distribution of the internal exposure (is not the subject of the present work, but it is similarly problematic. In this situation it is very difficult to search the dose-effect relationships exactly, and is also difficult to satisfy the people that their fears are unjustified. Society pays the costs of the nuclear industry and of the possible consequences as well. But society can neither control the nuclear industry nor the possible consequences at all. Both science and single people are waiting for more and detailed information. If we can not decrease the r adiation sensitivity of societies , then the consequences of Chernobyl will be growing unnecessarily, and it can strongly retard the justified development of the nuclear industry as well. (author)

  18. MiR-33a Decreases High-Density Lipoprotein-Induced Radiation Sensitivity in Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, Adam R.; Bambhroliya, Arvind [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Reddy, Jay P. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Debeb, Bisrat G. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Huo, Lei [Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Larson, Richard; Li, Li [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Ueno, Naoto T. [Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Woodward, Wendy A., E-mail: wwoodward@mdanderson.org [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2016-06-01

    Purpose: We previously showed that high-density lipoprotein (HDL) radiosensitizes inflammatory breast cancer (IBC) cells in vitro and is associated with better local control after radiation therapy in IBC patients. The microRNA miR-33 family negatively regulates the adenosine triphosphate binding cassette transporter subfamily A member 1. We hypothesized that variations in miR-33a expression in IBC cancer cells versus non-IBC cells would correlate with radiation sensitivity following exposure to HDL in vitro. Methods and Materials: MiR-33a expression was analyzed by reverse transcriptase–polymerase chain reaction in 4 cell lines representing common clinical breast cancer subtypes. Overexpression and knockdown of miR-33a was demonstrated via transfection of an miR-33a mimic or an anti-miR-33a construct in high- and low-expressing miR-33a cell lines. Clonogenic survival in vitro in these cells was quantified at baseline and following HDL treatment. MiR-33a expression on distant relapse-free survival (DRFS) of 210 cases downloaded from the Oxford breast cancer dataset was determined. Results: Expression levels of miR-33a were lower in IBC cell lines and IBC tumor samples than in non-IBC cell lines and normal breast tissue. Cholesterol concentrations in the cell membranes were higher in IBC cells than in non-IBC cells. Clonogenic survival following 24 hours of HDL treatment was decreased in response to irradiation in the low-miR-33a–expressing cell lines SUM149 and KPL4, but survival following HDL treatment decreased in the high-miR-33a–expressing cell lines MDA-MB-231 and SUM159. In the high-miR-33a–expressing cell lines, anti-miR-33a transfection decreased radiation resistance in clonogenic assays. Conversely, in the low-miR-33a–expressing cell lines, the miR-33a mimic reversed the HDL-induced radiation sensitization. Breast cancer patients in the top quartile based on miR-33a expression had markedly lower rates of DRFS than the bottom quartile (P

  19. MiR-33a Decreases High-Density Lipoprotein-Induced Radiation Sensitivity in Breast Cancer

    International Nuclear Information System (INIS)

    Wolfe, Adam R.; Bambhroliya, Arvind; Reddy, Jay P.; Debeb, Bisrat G.; Huo, Lei; Larson, Richard; Li, Li; Ueno, Naoto T.; Woodward, Wendy A.

    2016-01-01

    Purpose: We previously showed that high-density lipoprotein (HDL) radiosensitizes inflammatory breast cancer (IBC) cells in vitro and is associated with better local control after radiation therapy in IBC patients. The microRNA miR-33 family negatively regulates the adenosine triphosphate binding cassette transporter subfamily A member 1. We hypothesized that variations in miR-33a expression in IBC cancer cells versus non-IBC cells would correlate with radiation sensitivity following exposure to HDL in vitro. Methods and Materials: MiR-33a expression was analyzed by reverse transcriptase–polymerase chain reaction in 4 cell lines representing common clinical breast cancer subtypes. Overexpression and knockdown of miR-33a was demonstrated via transfection of an miR-33a mimic or an anti-miR-33a construct in high- and low-expressing miR-33a cell lines. Clonogenic survival in vitro in these cells was quantified at baseline and following HDL treatment. MiR-33a expression on distant relapse-free survival (DRFS) of 210 cases downloaded from the Oxford breast cancer dataset was determined. Results: Expression levels of miR-33a were lower in IBC cell lines and IBC tumor samples than in non-IBC cell lines and normal breast tissue. Cholesterol concentrations in the cell membranes were higher in IBC cells than in non-IBC cells. Clonogenic survival following 24 hours of HDL treatment was decreased in response to irradiation in the low-miR-33a–expressing cell lines SUM149 and KPL4, but survival following HDL treatment decreased in the high-miR-33a–expressing cell lines MDA-MB-231 and SUM159. In the high-miR-33a–expressing cell lines, anti-miR-33a transfection decreased radiation resistance in clonogenic assays. Conversely, in the low-miR-33a–expressing cell lines, the miR-33a mimic reversed the HDL-induced radiation sensitization. Breast cancer patients in the top quartile based on miR-33a expression had markedly lower rates of DRFS than the bottom quartile (P

  20. Comparison of the sensitivity of surface downward longwave radiation to changes in water vapor at two high elevation sites

    International Nuclear Information System (INIS)

    Chen, Yonghua; Naud, Catherine M; Rangwala, Imtiaz; Landry, Christopher C; Miller, James R

    2014-01-01

    Among the potential reasons for enhanced warming rates in many high elevation regions is the nonlinear relationship between surface downward longwave radiation (DLR) and specific humidity (q). In this study we use ground-based observations at two neighboring high elevation sites in Southwestern Colorado that have different local topography and are 1.3 km apart horizontally and 348 m vertically. We examine the spatial consistency of the sensitivities (partial derivatives) of DLR with respect to changes in q, and the sensitivities are obtained from the Jacobian matrix of a neural network analysis. Although the relationship between DLR and q is the same at both sites, the sensitivities are higher when q is smaller, which occurs more frequently at the higher elevation site. There is a distinct hourly distribution in the sensitivities at both sites especially for high sensitivity cases, although the range is greater at the lower elevation site. The hourly distribution of the sensitivities relates to that of q. Under clear skies during daytime, q is similar between the two sites, however under cloudy skies or at night, it is not. This means that the DLR–q sensitivities are similar at the two sites during daytime but not at night, and care must be exercised when using data from one site to infer the impact of water vapor feedbacks at another site, particularly at night. Our analysis suggests that care should be exercised when using the lapse rate adjustment to infill high frequency data in a complex topographical region, particularly when one of the stations is subject to cold air pooling as found here. (letter)

  1. Comparison of the Sensitivity of Surface Downward Longwave Radiation to Changes in Water Vapor at Two High Elevation Sites

    Science.gov (United States)

    Chen, Yonghua; Naud, Catherine M.; Rangwala, Imtiaz; Landry, Christopher C.; Miller, James R.

    2014-01-01

    Among the potential reasons for enhanced warming rates in many high elevation regions is the nonlinear relationship between surface downward longwave radiation (DLR) and specific humidity (q). In this study we use ground-based observations at two neighboring high elevation sites in Southwestern Colorado that have different local topography and are 1.3 kilometers apart horizontally and 348 meters vertically. We examine the spatial consistency of the sensitivities (partial derivatives) of DLR with respect to changes in q, and the sensitivities are obtained from the Jacobian matrix of a neural network analysis. Although the relationship between DLR and q is the same at both sites, the sensitivities are higher when q is smaller, which occurs more frequently at the higher elevation site. There is a distinct hourly distribution in the sensitivities at both sites especially for high sensitivity cases, although the range is greater at the lower elevation site. The hourly distribution of the sensitivities relates to that of q. Under clear skies during daytime, q is similar between the two sites, however under cloudy skies or at night, it is not. This means that the DLR-q sensitivities are similar at the two sites during daytime but not at night, and care must be exercised when using data from one site to infer the impact of water vapor feedbacks at another site, particularly at night. Our analysis suggests that care should be exercised when using the lapse rate adjustment to infill high frequency data in a complex topographical region, particularly when one of the stations is subject to cold air pooling as found here.

  2. Radiation sensitive solid state devices

    International Nuclear Information System (INIS)

    Shannon, J.M.; Ralph, J.E.

    1975-01-01

    A solid state radiation sensitive device is described employing JFETs as the sensitive elements. Two terminal construction is achieved by using a common conductor to capacitively couple to the JFET gate and to one of the source and drain connections. (auth)

  3. Highly sensitive detection of ionizing radiations by a photoluminescent uranyl organic framework

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Jian; Wang, Yaxing; Liu, Wei; Yin, Xuemiao; Chen, Lanhua; Diwu, Juan; Chai, Zhifang; Wang, Shuao [School for Radiological and interdisciplinary Sciences (RAD-X) and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou (China); Zou, Youming [High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui (China); Albrecht-Schmitt, Thomas E. [Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL (United States); Liu, Guokui [Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL (United States)

    2017-06-19

    Precise detection of low-dose X- and γ-radiations remains a challenge and is particularly important for studying biological effects under low-dose ionizing radiation, safety control in medical radiation treatment, survey of environmental radiation background, and monitoring cosmic radiations. We report here a photoluminescent uranium organic framework, whose photoluminescence intensity can be accurately correlated with the exposure dose of X- or γ-radiations. This allows for precise and instant detection of ionizing radiations down to the level of 10{sup -4} Gy, representing a significant improvement on the detection limit of approximately two orders of magnitude, compared to other chemical dosimeters reported up to now. The electron paramagnetic resonance analysis suggests that with the exposure to radiations, the carbonyl double bonds break affording oxo-radicals that can be stabilized within the conjugated uranium oxalate-carboxylate sheet. This gives rise to a substantially enhanced equatorial bonding of the uranyl(VI) ions as elucidated by the single-crystal structure of the γ-ray irradiated material, and subsequently leads to a very effective photoluminescence quenching through phonon-assisted relaxation. The quenched sample can be easily recovered by heating, enabling recycled detection for multiple runs. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Oyster radiation sensitivity

    International Nuclear Information System (INIS)

    Marchese, Sandra R.M.; Mastro, Nelida L. del

    1996-01-01

    Various food products like oysters, crabs and shrimps have been described as possible Vibrio spp. transmitting agents. Seafood irradiation is been presented as an alternative among the different public health intervention measures to control food borne diseases. The objective of this work was to establish, firstly, the radioresistance of Crassostrea brasiliana oysters. The oysters were irradiated with Co-60 radiation with doses of 0, 1.5,3 and 6 kGy. Survival curves a function of time showed that 100% of samples irradiated with 3 kGy survived at least 6 days; among those irradiated with 6 kGy, 100% survived 3 days. These results are encouraging since a dose of 2 kGy is already effective in diminishing oyster bioburden. (author)

  5. Studies on the radiation sensitivity of food microorganism by high dose irradiation

    International Nuclear Information System (INIS)

    Hwang, Han Joon; Lee, Eun Jung; Yu, Hyun Hee; Lee, Jae Ho

    2010-04-01

    We investigated the radio resistance of pathogenic microorganisms (Bacillus cereus, Staphylococcus aureus, Methicillin resistant Staphylococcus aureus(MRSA) and Escherichia coli O157) in irradiating environments. Their radiation conditions of pathogenic microorganisms varied with pH(3-10), salt concentration(1-15%), temperature(-20, 4 and 25 .deg. C) and atmospheric condition. In addition, the effect of γ-irradiation on the inactivation of pathogenic microorganisms inoculated into food (saengsik, sliced ham, chopped beef) was investigated. The radiation dose ranged from 0 to 3 kGy. The γ--irradiated B.cereus(γ--BC) St.aureus(γ--SA), MRSA(γ--MRSA) and E.coli O157(γ--EC) were then cultured and the viable cell count on plate count agar and D10-values(dose required to inactivate 90% of a microbial population) were calculated. The number of pathogenic microorganisms at pH(3-10) and salt concentration(1-15%), temperature(-20, 4 and 25 .deg. C) and atmospheric condition decreased by 1 log CFU/ml after irradiation. The D 10 -value of γ--SA in the optimum condition was 0.152 kGy, and these of γ--MRSA and γ--EC were 0.346 and 0.240 kGy, respectively. The initial cell counts of pathogenic microorganisms in culture broth were slightly decreased as the decrease of pH and the increase of salt concentration. However, radiation resistance of pathogenic microorganisms was increased at frozen state. Moreover, D 10 -values of these is test strains in saengsik, sliced ham and chopped beef were 0.597, 0.226 , 0.398 and 0.416 kGy, respectively. These results provide the basic information for the in activation of pathogenic microorganisms in foods by irradiation

  6. Studies on the radiation sensitivity of food microorganism by high dose irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Han Joon; Lee, Eun Jung; Yu, Hyun Hee; Lee, Jae Ho [Korea University, Seoul (Korea, Republic of)

    2010-04-15

    We investigated the radio resistance of pathogenic microorganisms (Bacillus cereus, Staphylococcus aureus, Methicillin resistant Staphylococcus aureus(MRSA) and Escherichia coli O157) in irradiating environments. Their radiation conditions of pathogenic microorganisms varied with pH(3-10), salt concentration(1-15%), temperature(-20, 4 and 25 .deg. C) and atmospheric condition. In addition, the effect of {gamma}-irradiation on the inactivation of pathogenic microorganisms inoculated into food (saengsik, sliced ham, chopped beef) was investigated. The radiation dose ranged from 0 to 3 kGy. The {gamma}--irradiated B.cereus({gamma}--BC) St.aureus({gamma}--SA), MRSA({gamma}--MRSA) and E.coli O157({gamma}--EC) were then cultured and the viable cell count on plate count agar and D10-values(dose required to inactivate 90% of a microbial population) were calculated. The number of pathogenic microorganisms at pH(3-10) and salt concentration(1-15%), temperature(-20, 4 and 25 .deg. C) and atmospheric condition decreased by 1 log CFU/ml after irradiation. The D{sub 10}-value of {gamma}--SA in the optimum condition was 0.152 kGy, and these of {gamma}--MRSA and {gamma}--EC were 0.346 and 0.240 kGy, respectively. The initial cell counts of pathogenic microorganisms in culture broth were slightly decreased as the decrease of pH and the increase of salt concentration. However, radiation resistance of pathogenic microorganisms was increased at frozen state. Moreover, D{sub 10}-values of these is test strains in saengsik, sliced ham and chopped beef were 0.597, 0.226 , 0.398 and 0.416 kGy, respectively. These results provide the basic information for the in activation of pathogenic microorganisms in foods by irradiation

  7. High-throughput identification of ionizing radiation-sensitive plant genes and development of radiation indicator plant and radiation sensing Genechip

    International Nuclear Information System (INIS)

    Kim, Dong Sub; Kim, Jinbaek; Ha, Bokeun; Kim, Sang Hoon; Kim, Sunhee

    2013-05-01

    Physiological analysis of monocot model plant (rice) in response to ionizing radiation (cosmic-ray, gamma-ray, Ion beam). - Identification of antioxidant characters through cytochemical analysis. - Comparison of antioxidant activities in response to ionizing irradiation. - Evaluation of anthocyanin quantity in response to ionizing irradiation. Ionization energy response gene family analysis via bioinformatic validation. - Expression analysis of monocot and dicot gene families. - In silico and bioinformatic approach to elucidate gene function. Characterization and functional analysis of genes specifically expressed in response to ionizing irradiation (cosmic-ray, gamma-ray, Ion beam). - High throughput trancriptomic analysis of plants under ionizing radiation using microarray. - Promotor and cis-element analysis of genes specifically expressed in response to ionizing radiation. - Validation and function analysis of candidate genes. - Elucidation of plant mechanism of sensing and response to ionization energy. Development of bioindicator plants detecting ionization energy. - Cloning and identification of 'Radio marker genes (RMG)'. - Development of Over-expression (O/E) or Knock-out (K/O) plant using RMG. Development of Genechip as an ionization energy detector. - Expression profiling analysis of genes specifically expression in response to ionization energy. - Prepare high-conserved gene specific oligomer. - Development of ionization energy monitoring Genechip and application

  8. High-throughput identification of ionizing radiation-sensitive plant genes and development of radiation indicator plant and radiation sensing Genechip

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Sub; Kim, Jinbaek; Ha, Bokeun; Kim, Sang Hoon; Kim, Sunhee

    2013-05-15

    Physiological analysis of monocot model plant (rice) in response to ionizing radiation (cosmic-ray, gamma-ray, Ion beam). - Identification of antioxidant characters through cytochemical analysis. - Comparison of antioxidant activities in response to ionizing irradiation. - Evaluation of anthocyanin quantity in response to ionizing irradiation. Ionization energy response gene family analysis via bioinformatic validation. - Expression analysis of monocot and dicot gene families. - In silico and bioinformatic approach to elucidate gene function. Characterization and functional analysis of genes specifically expressed in response to ionizing irradiation (cosmic-ray, gamma-ray, Ion beam). - High throughput trancriptomic analysis of plants under ionizing radiation using microarray. - Promotor and cis-element analysis of genes specifically expressed in response to ionizing radiation. - Validation and function analysis of candidate genes. - Elucidation of plant mechanism of sensing and response to ionization energy. Development of bioindicator plants detecting ionization energy. - Cloning and identification of 'Radio marker genes (RMG)'. - Development of Over-expression (O/E) or Knock-out (K/O) plant using RMG. Development of Genechip as an ionization energy detector. - Expression profiling analysis of genes specifically expression in response to ionization energy. - Prepare high-conserved gene specific oligomer. - Development of ionization energy monitoring Genechip and application.

  9. Radiation sensitivity of mammalian cells

    International Nuclear Information System (INIS)

    Koch, C.J.

    1985-01-01

    The authors tested various aspects of the so-called ''competition'' model for radiation sensitization/protection. In this model, sensitizers and/or protectors react in first order chemical reactions with radiation-induced target radicals in the cell, producing damage fixation or repair respectively. It is only because of these parallel, first-order competing reactions that they may assign net amounts of damage on the basis of the chemical reactivity of the sentiziers/protectors with the radicals. It might be expected that such a simple model could not explain all aspects of cellular radiosensitivity and this has indeed been found to be true. However, one is able, with the simple model, to pose quite specific questions, and obtain quantitative information with respect to the relative agreement between experiment and theory. Many experiments by several investigators have found areas of disagreement with the competition theory, particularly with respect to the follow items: 1) role of cellular glutathione as the most important endogeneous radiation protector 2) characteristics of various sensitizers which cause them to behave differently from each other 3) methods relating to the quantitative kinetic analysis of experimenal results. This paper addresses these specific areas of disagreement from both an experimental and theoretical basis

  10. Toxic clinical hypoxic radiation sensitizers plus radiation-induced toxicity

    International Nuclear Information System (INIS)

    Richmond, R.C.

    1984-01-01

    The operational definition espoused twelve years ago that clinical hypoxic radiation sensitizers should be nontoxic interferes with the recognition and research of useful radiation sensitizers. Eight years ago the toxic antitumor drug cis-dichlorodiammineplatinum(II) was reported to be a hypoxic radiation sensitizer and the selective antitumor action of this drug was stressed as potentially creating tumor-targeted radiation sensitization. This rationale of oxidative antitumor drugs as toxic and targeted clinical sensitizers is useful, and has led to the study reported here. The antitumor drug cis-(1,1-cyclobutane-dicarboxylato)diammineplatinum(II), or JM-8, is being tested in clinical trials. Cells of S. typhimurium in PBS in the presence of 0.2mM JM-8 are found to be sensitized to irradiation under hypoxic, but not oxic, conditions. JM-8 is nontoxic to bacteria at this concentration, but upon irradiation the JM-8 solution becomes highly toxic. This radiation induced toxicity of JM-8 preferentially develops from hypoxic solution, and thus contributes to the rationale of hypoxic tumor cell destruction

  11. High energy radiation detector

    International Nuclear Information System (INIS)

    Vosburgh, K.G.

    1975-01-01

    The high energy radiation detector described comprises a set of closely spaced wedge reflectors. Each wedge reflector is composed of three sides forming identical isoceles triangles with a common apex and an open base forming an equilateral triangle. The length of one side of the base is less than the thickness of the coat of material sensitive to high energy radiation. The wedge reflectors reflect the light photons spreading to the rear of the coat in such a way that each reflected track is parallel to the incident track of the light photon spreading rearwards. The angle of the three isosceles triangles with a common apex is between 85 and 95 deg. The first main surface of the coat of high energy radiation sensitive material is in contact with the projecting edges of the surface of the wedge reflectors of the reflecting element [fr

  12. Photodiode array for position-sensitive detection using high X-ray flux provided by synchrotron radiation

    Science.gov (United States)

    Jucha, A.; Bonin, D.; Dartyge, E.; Flank, A. M.; Fontaine, A.; Raoux, D.

    1984-09-01

    Synchrotron radiation provides a high intensity source over a large range of wavelengths. This is the prominent quality that has laid the foundations of the EXAFS development (Extended X-ray Absorption Fine Structure). EXAFS data can be collected in different ways. A full scan requires 5 to 10 min, compared to the one-day data collection of a conventional Bremsstrahlung X-ray tube. Recently, by using the new photodiode array (R 1024 SFX) manufactured by Reticon, it has been possible to reduce the data collection time to less than 100 ms. The key elements of this new EXAFS method are a dispersive optics combined with a position sensitive detector able to work under very high flux conditions. The total aperture of 2500 μm × 25 μm for each pixel is well suited to spectroscopic applications. Besides its high dynamic range (> 10 4) and its linearity, the rapidity of the readout allows a flux of 10 9-10 10 photons/s over the 1024 sensing elements.

  13. SEM probe of IC radiation sensitivity

    Science.gov (United States)

    Gauthier, M. K.; Stanley, A. G.

    1979-01-01

    Scanning Electron Microscope (SEM) used to irradiate single integrated circuit (IC) subcomponent to test for radiation sensitivity can localize area of IC less than .03 by .03 mm for determination of exact location of radiation sensitive section.

  14. Highly sensitive and quantitative FRET-FLIM imaging in single dendritic spines using improved non-radiative YFP.

    Science.gov (United States)

    Murakoshi, Hideji; Lee, Seok-Jin; Yasuda, Ryohei

    2008-08-01

    Two-photon fluorescence lifetime imaging microscopy (TPFLIM) enables the quantitative measurements of fluorescence resonance energy transfer (FRET) in small subcellular compartments in light scattering tissue. We evaluated and optimized the FRET pair of mEGFP (monomeric EGFP with the A206K mutation) and REACh (non-radiative YFP variants) for TPFLIM. We characterized several mutants of REACh in terms of their "darkness," and their ability to act as a FRET acceptor for mEGFP in HeLa cells and hippocampal neurons. Since the commonly used monomeric mutation A206K increases the brightness of REACh, we introduced a different monomeric mutation (F223R) which does not affect the brightness. Also, we found that the folding efficiency of original REACh, as measured by the fluorescence lifetime of a mEGFP-REACh tandem dimer, was low and variable from cell to cell. Introducing two folding mutations (F46L, Q69M) into REACh increased the folding efficiency by approximately 50%, and reduced the variability of FRET signal. Pairing mEGFP with the new REACh (super-REACh, or sREACh) improved the signal-to-noise ratio compared to the mEGFP-mRFP or mEGFP-original REACh pair by approximately 50%. Using this new pair, we demonstrated that the fraction of actin monomers in filamentous and globular forms in single dendritic spines can be quantitatively measured with high sensitivity. Thus, the mEGFP-sREACh pair is suited for quantitative FRET measurement by TPFLIM, and enables us to measure protein-protein interactions in individual dendritic spines in brain slices with high sensitivity.

  15. Non-nitro radiation sensitizers

    International Nuclear Information System (INIS)

    Jacobs, G.P.

    1986-01-01

    This short communication aims to update the review of non-nitro radiation sensitizers (Shenoy and Singh 1985) and correct omissions. Work is mentioned and bibliography given for studied of cis-platinum, potassium permanganate, cobalt hexammine, sodium bromide, dimethylsulphoxide, zinc and copper ions, organic nitroxyl free radicals (TAN,TMPN and NPPN + PNAP), halogenated pyrimidines, organic and inorganic iodine containing compounds, diacetyl, acetone and acetophenone, rho-hydrobenzoic acid and its esters, pentobarbitone and secobarbitone, heparin and 9-anilinoacridines, dehydropiandosterone and paraquat. (U.K.)

  16. Radiation-sensitive switching circuits

    Energy Technology Data Exchange (ETDEWEB)

    Moore, J.H.; Cockshott, C.P.

    1976-03-16

    A radiation-sensitive switching circuit has a light emitting diode which supplies light to a photo-transistor, the light being interrupted from time to time. When the photo-transistor is illuminated, current builds up and when this current reaches a predetermined value, a trigger circuit changes state. The peak output of the photo-transistor is measured and the trigger circuit is arranged to change state when the output of the device is a set proportion of the peak output, so as to allow for aging of the components. The circuit is designed to control the ignition system in an automobile engine.

  17. Radiation-sensitive switching circuits

    Energy Technology Data Exchange (ETDEWEB)

    Moore, J.H.; Cockshott, C.P.

    1976-03-16

    A radiation-sensitive switching circuit includes a light emitting diode which from time to time illuminates a photo-transistor, the photo-transistor serving when its output reaches a predetermined value to operate a trigger circuit. In order to allow for aging of the components, the current flow through the diode is increased when the output from the transistor falls below a known level. Conveniently, this is achieved by having a transistor in parallel with the diode, and turning the transistor off when the output from the phototransistor becomes too low. The circuit is designed to control the ignition system in an automobile engine.

  18. Evidence for a high and a low sensitivity receptor site for radiation-induced vomiting in the dog

    International Nuclear Information System (INIS)

    Harding, R.K.; Hugenholtz, H.; Kucharczyk, J.

    1987-01-01

    Ablation of the area postrema (AP) has been shown to prevent radiation-induced vomiting in the dog (induced by 6-8 By /sup 60/Co γ). In other species (cat, monkey) a higher dose of radiation is necessary to elicit emesis and visceral deafferentation has been more effective than AP ablation in preventing vomiting. The AP and the dorsal motor nucleus of the vagus (DMV), an important visceral afferent terminus, are anatomically adjacent structures in the medulla oblongata. Aggressive AP ablation could affect the DMV. The author's removed the AP in 6 dogs. Previous work showed this surgery prevented vomiting following exposure to 6-8 Gy. To prove the lesion did not invade the underlying DMV, the animals were given a hypertonic saline gavage, to elicit vomiting via visceral receptors. Animals were later submitted to 15-20 Gy. Those with proved visceral afferent connections vomited. They conclude that the AP is the most sensitive site for the stimulation of radiation-induced vomiting and that a less sensitive visceral site also exists. Differences in the relative sensitivities of these 2 systems may account for published species differences

  19. Radiation sensitive polymer gel dosimeters

    International Nuclear Information System (INIS)

    Lepage, M.; Back, S.A.J.; Baldock, C.; Whittaker, A.K.; Rintoul, L.

    2000-01-01

    Full text: Radiation sensitive gels are studied for their potential to retain a permanent 3D dose distribution for applications in radiotherapy. Co-monomers dissolved in a tissue-equivalent hydrogel undergo a polymerization reaction upon absorption of ionizing radiation. The polymer formed influences the local spin-spin relaxation time (T 2 ) of the dosimeter that can be determined using magnetic resonance imaging (MRI). The relationship between T2 and the absorbed dose was studied for different initial chemical compositions. The aim was to find a model linking the changes in T 2 with absorbed dose to the initial composition of the dosimeter. It is believed this will help designing new gel dosimeters having desired properties to minimize the uncertainty in the determination of the dose distribution. 1 H, 13 C nuclear magnetic resonance spectroscopy and FT-Raman spectroscopy were used to quantify the amount of monomers still remaining after the absorption of a given dose of radiation. This data is used to model the changes of T2 as a function of the absorbed dose. A model of fast exchange of magnetization between three proton pools was used, where the fraction of protons (f x H ) in the x th pool is obtained from the chemical composition of the dosimeter and the apparent T2 of each pool is determined for a given composition. Initially, the protons are contained in two pools; a mobile (mob), which contains the water protons and the monomers protons, and a gelatin (gela) proton pool. The mobile pool is partially depleted as polymer is formed, the protons are transferred into the polymer (pol) pool. In the figure, the experimental data along with the calculated values are plotted for three different monomer concentrations, with the gelatin concentration fixed. The model is seen to provide a good fit to the experimental data

  20. Measurement of low-LET radiation dose aboard the chinese scientific experiment satellite (1988) by highly sensitive LiF (Mg, Cu, P) TL chips

    International Nuclear Information System (INIS)

    Zhang Zhonglun; Zheng Yanzhen.

    1989-01-01

    Low-LET radiation dose is an important portion of spaceflight dose. It is a new application that highly sensitive LiF(Mg, Cu, P) TL chips are used in measurement of low-LET dose aboard the chinese scientific experiment satellite. Avarage dose rate in satellite is 9.2 mrad/day and on the ground is about 0.32 mrad/day

  1. High-Sensitivity Spectrophotometry.

    Science.gov (United States)

    Harris, T. D.

    1982-01-01

    Selected high-sensitivity spectrophotometric methods are examined, and comparisons are made of their relative strengths and weaknesses and the circumstances for which each can best be applied. Methods include long path cells, noise reduction, laser intracavity absorption, thermocouple calorimetry, photoacoustic methods, and thermo-optical methods.…

  2. Highly Sensitive Optical Receivers

    CERN Document Server

    Schneider, Kerstin

    2006-01-01

    Highly Sensitive Optical Receivers primarily treats the circuit design of optical receivers with external photodiodes. Continuous-mode and burst-mode receivers are compared. The monograph first summarizes the basics of III/V photodetectors, transistor and noise models, bit-error rate, sensitivity and analog circuit design, thus enabling readers to understand the circuits described in the main part of the book. In order to cover the topic comprehensively, detailed descriptions of receivers for optical data communication in general and, in particular, optical burst-mode receivers in deep-sub-µm CMOS are presented. Numerous detailed and elaborate illustrations facilitate better understanding.

  3. Radiation sensitivity of different citric pectins

    Energy Technology Data Exchange (ETDEWEB)

    Inamura, Patricia Y.; Mastro, Nelida L. del [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mails: patyoko@yahoo.com; nlmastro@ipen.br

    2007-07-01

    Pectic substances are important soluble polysaccharides of plant origin of considerable interest for food industry as gelling agent and stabilizer in jams, fruit jellies, yogurt drinks and lactic acid beverages. Polysaccharides can be degraded by ionizing radiation due to the free radical induced scission of the glycosidic bonds. Viscosity methods had been used to determine the efficiency of hydroxyl radical induced chain breaks generation in macromolecules. In the present work samples of pectin with different degree of methoxylation were employed in order to study their radiation sensitivity by means of viscosity measurements. Samples of citric pectin 1% solutions were irradiated with gamma rays at different doses, ranging from 0 to 15 kGy, using a {sup 60}Co Gammacell 220 (AECL), dose rate about 2 kGy/h. After irradiation the viscosity was measured on the viscometer Brookfield model LV-DVIII at 50, 60 and 70 deg C within a period of 48h. Pectin viscosity with high degree of methoxylation decreased sharply with the radiation dose remaining almost constant from 10 kGy. Pectin with low degree of methoxylation presented initially higher values of viscosity and the radiation induced decrease was also pronounced. Viscosity measurements decreased with the increase of the temperature applied for both kind of samples. The effect of radiation induced chain breaks generation in pectin molecules was evident through the viscosity reduction of irradiated pectin solutions although the viscosity presented diverse values depending of the degree of methoxylation of carboxyl groups in the backbone of polysaccharide macromolecules. (author)

  4. Radiation sensitivity of different citric pectins

    International Nuclear Information System (INIS)

    Inamura, Patricia Y.; Mastro, Nelida L. del

    2007-01-01

    Pectic substances are important soluble polysaccharides of plant origin of considerable interest for food industry as gelling agent and stabilizer in jams, fruit jellies, yogurt drinks and lactic acid beverages. Polysaccharides can be degraded by ionizing radiation due to the free radical induced scission of the glycosidic bonds. Viscosity methods had been used to determine the efficiency of hydroxyl radical induced chain breaks generation in macromolecules. In the present work samples of pectin with different degree of methoxylation were employed in order to study their radiation sensitivity by means of viscosity measurements. Samples of citric pectin 1% solutions were irradiated with gamma rays at different doses, ranging from 0 to 15 kGy, using a 60 Co Gammacell 220 (AECL), dose rate about 2 kGy/h. After irradiation the viscosity was measured on the viscometer Brookfield model LV-DVIII at 50, 60 and 70 deg C within a period of 48h. Pectin viscosity with high degree of methoxylation decreased sharply with the radiation dose remaining almost constant from 10 kGy. Pectin with low degree of methoxylation presented initially higher values of viscosity and the radiation induced decrease was also pronounced. Viscosity measurements decreased with the increase of the temperature applied for both kind of samples. The effect of radiation induced chain breaks generation in pectin molecules was evident through the viscosity reduction of irradiated pectin solutions although the viscosity presented diverse values depending of the degree of methoxylation of carboxyl groups in the backbone of polysaccharide macromolecules. (author)

  5. Radiation sensitive area detection device and method

    Science.gov (United States)

    Carter, Daniel C. (Inventor); Hecht, Diana L. (Inventor); Witherow, William K. (Inventor)

    1991-01-01

    A radiation sensitive area detection device for use in conjunction with an X ray, ultraviolet or other radiation source is provided which comprises a phosphor containing film which releases a stored diffraction pattern image in response to incoming light or other electromagnetic wave. A light source such as a helium-neon laser, an optical fiber capable of directing light from the laser source onto the phosphor film and also capable of channelling the fluoresced light from the phosphor film to an integrating sphere which directs the light to a signal processing means including a light receiving means such as a photomultiplier tube. The signal processing means allows translation of the fluoresced light in order to detect the original pattern caused by the diffraction of the radiation by the original sample. The optical fiber is retained directly in front of the phosphor screen by a thin metal holder which moves up and down across the phosphor screen and which features a replaceable pinhole which allows easy adjustment of the resolution of the light projected onto the phosphor film. The device produces near real time images with high spatial resolution and without the distortion that accompanies prior art devices employing photomultiplier tubes. A method is also provided for carrying out radiation area detection using the device of the invention.

  6. Sensitivity to Antibiotics of Bacteria Exposed to Gamma Radiation Emitted from Hot Soils of the High Background Radiation Areas of Ramsar, Northern Iran.

    Science.gov (United States)

    Mortazavi, Seyed Mohammad Javad; Zarei, Samira; Taheri, Mohammad; Tajbakhsh, Saeed; Mortazavi, Seyed Alireza; Ranjbar, Sahar; Momeni, Fatemeh; Masoomi, Samaneh; Ansari, Leila; Movahedi, Mohammad Mehdi; Taeb, Shahram; Zarei, Sina; Haghani, Masood

    2017-04-01

    Over the past several years our laboratories have investigated different aspects of the challenging issue of the alterations in bacterial susceptibility to antibiotics induced by physical stresses. To explore the bacterial susceptibility to antibiotics in samples of Salmonella enterica subsp. enterica serovar Typhimurium ( S. typhimurium ), Staphylococcus aureus , and Klebsiella pneumoniae after exposure to gamma radiation emitted from the soil samples taken from the high background radiation areas of Ramsar, northern Iran. Standard Kirby-Bauer test, which evaluates the size of the zone of inhibition as an indicator of the susceptibility of different bacteria to antibiotics, was used in this study. The maximum alteration of the diameter of inhibition zone was found for K. pneumoniae when tested for ciprofloxacin. In this case, the mean diameter of no growth zone in non-irradiated control samples of K. pneumoniae was 20.3 (SD 0.6) mm; it was 14.7 (SD 0.6) mm in irradiated samples. On the other hand, the minimum changes in the diameter of inhibition zone were found for S. typhimurium and S. aureus when these bacteria were tested for nitrofurantoin and cephalexin, respectively. Gamma rays were capable of making significant alterations in bacterial susceptibility to antibiotics. It can be hypothesized that high levels of natural background radiation can induce adaptive phenomena that help microorganisms better cope with lethal effects of antibiotics.

  7. Sensitivity to Antibiotics of Bacteria Exposed to Gamma Radiation Emitted from Hot Soils of the High Background Radiation Areas of Ramsar, Northern Iran

    Directory of Open Access Journals (Sweden)

    Seyed Mohammad Javad Mortazavi

    2017-04-01

    Full Text Available Background: Over the past several years our laboratories have investigated different aspects of the challenging issue of the alterations in bacterial susceptibility to antibiotics induced by physical stresses. Objective: To explore the bacterial susceptibility to antibiotics in samples of Salmonella enterica subsp. enterica serovar Typhimurium (S. typhimurium, Staphylococcus aureus, and Klebsiella pneumoniae after exposure to gamma radiation emitted from the soil samples taken from the high background radiation areas of Ramsar, northern Iran. Methods: Standard Kirby-Bauer test, which evaluates the size of the zone of inhibition as an indicator of the susceptibility of different bacteria to antibiotics, was used in this study. Results: The maximum alteration of the diameter of inhibition zone was found for K. pneumoniae when tested for ciprofloxacin. In this case, the mean diameter of no growth zone in non-irradiated control samples of K. pneumoniae was 20.3 (SD 0.6 mm; it was 14.7 (SD 0.6 mm in irradiated samples. On the other hand, the minimum changes in the diameter of inhibition zone were found for S. typhimurium and S. aureus when these bacteria were tested for nitrofurantoin and cephalexin, respectively. Conclusion: Gamma rays were capable of making significant alterations in bacterial susceptibility to antibiotics. It can be hypothesized that high levels of natural background radiation can induce adaptive phenomena that help microorganisms better cope with lethal effects of antibiotics.

  8. High-Density and Very-Low-Density Lipoprotein Have Opposing Roles in Regulating Tumor-Initiating Cells and Sensitivity to Radiation in Inflammatory Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, Adam R. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Atkinson, Rachel L. [Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Reddy, Jay P. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Debeb, Bisrat G.; Larson, Richard; Li, Li [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Clinical Cancer Prevention, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Masuda, Hiroko; Brewer, Takae [Department of Clinical Cancer Prevention, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Atkinson, Bradley J. [Department of Clinical Pharmacy Services, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Brewster, Abeena [Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Ueno, Naoto T. [Department of Clinical Cancer Prevention, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Woodward, Wendy A., E-mail: wwoodward@mdanderson.org [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Clinical Cancer Prevention, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2015-04-01

    Purpose: We previously demonstrated that cholesterol-lowering agents regulate radiation sensitivity of inflammatory breast cancer (IBC) cell lines in vitro and are associated with less radiation resistance among IBC patients who undergo postmastectomy radiation. We hypothesized that decreasing IBC cellular cholesterol induced by treatment with lipoproteins would increase radiation sensitivity. Here, we examined the impact of specific transporters of cholesterol (ie lipoproteins) on the responses of IBC cells to self-renewal and to radiation in vitro and on clinical outcomes in IBC patients. Methods and Materials: Two patient-derived IBC cell lines, SUM 149 and KPL4, were incubated with low-density lipoproteins (LDL), very-low-density lipoproteins (VLDL), or high-density lipoproteins (HDL) for 24 hours prior to irradiation (0-6 Gy) and mammosphere formation assay. Cholesterol panels were examined in a cohort of patients with primary IBC diagnosed between 1995 and 2011 at MD Anderson Cancer Center. Lipoprotein levels were then correlated to patient outcome, using the log rank statistical model, and examined in multivariate analysis using Cox regression. Results: VLDL increased and HDL decreased mammosphere formation compared to untreated SUM 149 and KPL4 cells. Survival curves showed enhancement of survival in both of the IBC cell lines when pretreated with VLDL and, conversely, radiation sensitization in all cell lines when pretreated with HDL. In IBC patients, higher VLDL values (>30 mg/dL) predicted a lower 5-year overall survival rate than normal values (hazard ratio [HR] = 1.9 [95% confidence interval [CI]: 1.05-3.45], P=.035). Lower-than-normal patient HDL values (<60 mg/dL) predicted a lower 5-year overall survival rate than values higher than 60 mg/dL (HR = 3.21 [95% CI: 1.25-8.27], P=.015). Conclusions: This study discovered a relationship among the plasma levels of lipoproteins, overall patient response, and radiation resistance in IBC patients

  9. High-Density and Very-Low-Density Lipoprotein Have Opposing Roles in Regulating Tumor-Initiating Cells and Sensitivity to Radiation in Inflammatory Breast Cancer

    International Nuclear Information System (INIS)

    Wolfe, Adam R.; Atkinson, Rachel L.; Reddy, Jay P.; Debeb, Bisrat G.; Larson, Richard; Li, Li; Masuda, Hiroko; Brewer, Takae; Atkinson, Bradley J.; Brewster, Abeena; Ueno, Naoto T.; Woodward, Wendy A.

    2015-01-01

    Purpose: We previously demonstrated that cholesterol-lowering agents regulate radiation sensitivity of inflammatory breast cancer (IBC) cell lines in vitro and are associated with less radiation resistance among IBC patients who undergo postmastectomy radiation. We hypothesized that decreasing IBC cellular cholesterol induced by treatment with lipoproteins would increase radiation sensitivity. Here, we examined the impact of specific transporters of cholesterol (ie lipoproteins) on the responses of IBC cells to self-renewal and to radiation in vitro and on clinical outcomes in IBC patients. Methods and Materials: Two patient-derived IBC cell lines, SUM 149 and KPL4, were incubated with low-density lipoproteins (LDL), very-low-density lipoproteins (VLDL), or high-density lipoproteins (HDL) for 24 hours prior to irradiation (0-6 Gy) and mammosphere formation assay. Cholesterol panels were examined in a cohort of patients with primary IBC diagnosed between 1995 and 2011 at MD Anderson Cancer Center. Lipoprotein levels were then correlated to patient outcome, using the log rank statistical model, and examined in multivariate analysis using Cox regression. Results: VLDL increased and HDL decreased mammosphere formation compared to untreated SUM 149 and KPL4 cells. Survival curves showed enhancement of survival in both of the IBC cell lines when pretreated with VLDL and, conversely, radiation sensitization in all cell lines when pretreated with HDL. In IBC patients, higher VLDL values (>30 mg/dL) predicted a lower 5-year overall survival rate than normal values (hazard ratio [HR] = 1.9 [95% confidence interval [CI]: 1.05-3.45], P=.035). Lower-than-normal patient HDL values (<60 mg/dL) predicted a lower 5-year overall survival rate than values higher than 60 mg/dL (HR = 3.21 [95% CI: 1.25-8.27], P=.015). Conclusions: This study discovered a relationship among the plasma levels of lipoproteins, overall patient response, and radiation resistance in IBC patients

  10. Radiation sensitivity of messenger RNA

    International Nuclear Information System (INIS)

    Ponta, H.; Pfennig-Yeh, M.L.; Herrlich, P.; Karlsruhe Univ.; Wagner, E.F.; Schweiger, M.

    1979-01-01

    Messenger RNA function is inactivated by irradiation with ultraviolet light. A unit length mRNA (in bases) is 2-3 times more sensitive than a unit length of DNA (in base pairs) with respect to the inactivation of template function. These data stem from four experimental systems all of which do not repair DNA: the translation of E. coli mRNA in rifampicin-treated cells, of T7 mRNA in infected E.coli, of f2 phage RNA in vivo, and of stable mRNA in chromosomeless minicells. The comparison of relative sensitivities to UV is relevant to the technique of UV mapping of transcription units which enjoys increasing popularity in pro- and eukaryotic genetic research. (orig.) [de

  11. Radiation sensitivity of messenger RNA

    Energy Technology Data Exchange (ETDEWEB)

    Ponta, H; Pfennig-Yeh, M L; Herrlich, P [Kernforschungszentrum Karlsruhe G.m.b.H. (Germany, F.R.). Inst. fuer Genetik und Toxikologie von Spaltstoffen; Karlsruhe Univ. (TH) (Germany, F.R.). Inst. fuer Genetik); Wagner, E F; Schweiger, M [Innsbruck Univ. (Austria). Inst. fuer Biochemie

    1979-08-01

    Messenger RNA function is inactivated by irradiation with ultraviolet light. A unit length mRNA (in bases) is 2-3 times more sensitive than a unit length of DNA (in base pairs) with respect to the inactivation of template function. These data stem from four experimental systems all of which do not repair DNA: the translation of E. coli mRNA in rifampicin-treated cells, of T7 mRNA in infected E.coli, of f2 phage RNA in vivo, and of stable mRNA in chromosomeless minicells. The comparison of relative sensitivities to UV is relevant to the technique of UV mapping of transcription units which enjoys increasing popularity in pro- and eukaryotic genetic research.

  12. Radiation sensitivity of integrated circuits Pt. 1

    International Nuclear Information System (INIS)

    Bereczkine Kerenyi, Ilona

    1986-01-01

    The cosmic ray sensitivity of CMOS integrated circuits are overviewed in three parts. The aim is to analyze the effects of ionizing radiation on the degradation of electronic parameters, the effects of the electric state during irradiation, and the radiation hardening of ICs. In this Part 1 a general introduction of the response of semiconductors to cosmic radiation is given, and the radiation tolerance and hardening of small-scale integrated CMOS ICs is analyzed in detail. The devices include various basic inverters and simple gate ICs. (R.P.)

  13. On the instability effects in radiation-sensitive chalcogenide glasses

    International Nuclear Information System (INIS)

    Balitska, V.; Kovalskiy, A.; Shpotyuk, O.; Vakiv, M.

    2007-01-01

    The features of application of radiation-sensitive media based on chalcogenide glasses of As-Ge-S system for registration of high-energy γ-radiation are analysed. It is shown that compositional features of the observed time-instability effect should be taken into account in order to ensure a higher accuracy of the developed dosimeters

  14. On the instability effects in radiation-sensitive chalcogenide glasses

    Energy Technology Data Exchange (ETDEWEB)

    Balitska, V. [Lviv State University for Vital Activity Safety, 35 Kleparivska str., Lviv, UA-79007 (Ukraine); Lviv Institute of Materials of SRC ' Carat' , 202 Stryjska str., Lviv, UA-79031 (Ukraine); Kovalskiy, A. [Lviv Institute of Materials of SRC ' Carat' , 202 Stryjska str., Lviv, UA-79031 (Ukraine); International Materials Institute for New Functionality in Glass, Lehigh University, 5 East Packer Avenue, Bethlehem, PA 18015-3195 (United States); Shpotyuk, O. [Lviv Institute of Materials of SRC ' Carat' , 202 Stryjska str., Lviv, UA-79031 (Ukraine); International Materials Institute for New Functionality in Glass, Lehigh University, 5 East Packer Avenue, Bethlehem, PA 18015-3195 (United States)], E-mail: shpotyuk@novas.lviv.ua; Vakiv, M. [Lviv Institute of Materials of SRC ' Carat' , 202 Stryjska str., Lviv, UA-79031 (Ukraine)

    2007-04-15

    The features of application of radiation-sensitive media based on chalcogenide glasses of As-Ge-S system for registration of high-energy {gamma}-radiation are analysed. It is shown that compositional features of the observed time-instability effect should be taken into account in order to ensure a higher accuracy of the developed dosimeters.

  15. Position-sensitive radiation detector

    International Nuclear Information System (INIS)

    Mathieson, E.; Smith, G.C.; Gilvin, P.J.

    1981-01-01

    Apparatus for sensing the position of radiation received has a plurality of receptors spaced in at least one line on which the position is to be determined, their outputs being associated to form at least two groups, the density of the receptors in each group varying along the line. The receptors may comprise cathode arrays of a multiwire proportional counter, with an anode array between, measuring along lines in directions x and y respectively. The density of the wires in the two groups, decreases in opposite directions. A circuit determines the ratio of the output of one group to the sum of the group outputs. In another embodiment a scintillator is viewed by a plurality of light guides, the ends of which adjacent to the scintillator form the receptors, the four groups of which each terminate on a photomultiplier. (author)

  16. Ultra-low dose dual-source high-pitch computed tomography of the paranasal sinus: diagnostic sensitivity and radiation dose

    International Nuclear Information System (INIS)

    Schulz, Boris; Zangos, Stefan; Friedrichs, Ingke; Bauer, Ralf W.; Kerl, Matthias; Vogl, Thomas J.; Martin M Mack, Martin M.; Potente, Stefan

    2012-01-01

    Background: Today's gold standard for diagnostic imaging of inflammatory diseases of the paranasal sinus is computed tomography (CT). Purpose: To evaluate diagnostic sensitivity and radiation dose of an ultra-low dose dual-source CT technique. Material and Methods: Paranasal sinuses of 14 cadaveric heads were independently evaluated by two readers using a modern dual-source CT with lowest reasonable dosage in high-pitch mode (100 kV, 10 mAs, collimation 0.6 mm, pitch value 3.0). Additionally the head part of an anthropomorphic Alderson-Rando phantom was equipped with thermoluminescent detectors to measure radiation exposure to the eye lenses and thyroid gland. Results: Diagnostic accuracy regarding sinusoidal fluid, nasal septum deviation, and mucosal swelling was 100%. Mastoid fluid was detected in 76% and 92%, respectively. In the phantom study, average measured eye lens dosage was 0.64 mGy; radiation exposure of the thyroid gland was 0.085 mGy. Conclusion: Regarding evaluation of inflammatory diseases of the paranasal sinus this study indicates sufficient accuracy of the proposed CT protocol at a very low dosage level

  17. Microenvironment around tumors and their radiation sensitivity. The possibility of molecular target for radiation sensitization

    Energy Technology Data Exchange (ETDEWEB)

    Akimoto, Tetsuo; Ishikawa, Hitoshi [Gunma Univ., Maebashi (Japan). School of Medicine; Mitsuhashi, Norio [Tokyo Women' s Medical Coll. (Japan)

    2001-12-01

    There have been scarce studies concerning the effect of microenvironment around tumors on their radiation sensitivity and this review describes the influence of environmental factors of cell adhesion, growth factors, cytokines, hypoxia and angiogenesis on the sensitivity and response to radiation and on the signal transduction to consider the possibility of molecular target for radiation sensitization. Cell-cell adhesion and cell-matrix interaction in response to radiation may have a role in inducing apoptotic process like anti-apoptotic or pro-apoptotic one. Growth factors and cytokines can affect the tumor response to radiation in more extent than p53 gene status since apoptosis induction is not always an indication of radiation sensitivity in many tumors clinically encountered. Radiation sensitivity is low in tumor cells under hypoxic conditions and it is important to know the relationship between those hypoxic cell response and angiogenesis by factors like HIF (hypoxia-inducible factor)-1. Molecular targets for radiation sensitization are now under development and both basic and clinical studies are important for future application of those sensitizing agents for the radiotherapy of tumors. (K.H.)

  18. Microenvironment around tumors and their radiation sensitivity. The possibility of molecular target for radiation sensitization

    International Nuclear Information System (INIS)

    Akimoto, Tetsuo; Ishikawa, Hitoshi

    2001-01-01

    There have been scarce studies concerning the effect of microenvironment around tumors on their radiation sensitivity and this review describes the influence of environmental factors of cell adhesion, growth factors, cytokines, hypoxia and angiogenesis on the sensitivity and response to radiation and on the signal transduction to consider the possibility of molecular target for radiation sensitization. Cell-cell adhesion and cell-matrix interaction in response to radiation may have a role in inducing apoptotic process like anti-apoptotic or pro-apoptotic one. Growth factors and cytokines can affect the tumor response to radiation in more extent than p53 gene status since apoptosis induction is not always an indication of radiation sensitivity in many tumors clinically encountered. Radiation sensitivity is low in tumor cells under hypoxic conditions and it is important to know the relationship between those hypoxic cell response and angiogenesis by factors like HIF (hypoxia-inducible factor)-1. Molecular targets for radiation sensitization are now under development and both basic and clinical studies are important for future application of those sensitizing agents for the radiotherapy of tumors. (K.H.)

  19. Modification of radiation sensitivity by edaravone

    Energy Technology Data Exchange (ETDEWEB)

    Sasano, Nakashi; Enomoto, Atsushi; Miyagawa, Kiyoshi [Tokyo Univ., Graduate School of Medicine, Tokyo (Japan); Hosoi, Yoshio [Niigata Univ., School of Health Sciences, Niigata, Niigata (Japan); Nakagawa, Keiichi [Tokyo Univ., Hospital, Tokyo (Japan)

    2009-03-15

    Studied was the effect of edaravone (E), a clinical therapeutic drug for brain infarction possessing properties of free radical scavenger, on apoptosis in vitro. Human T-cell leukemic MOLT-4 cells and p53-knockdown MOLT-4 cells which overexpressing short hairpin type p53 by siRNA treatment were X-irradiated by Shimadzu Pantak HF 350 machine at 135-140 cGy/min for 2-5 Gy in total, in the presence of E. Cell death was estimated by dye-exclusion, apoptosis by EPICS flow cytometry, cellular reactive oxygen species by chloromethyl-2',7'-dichlorodihydrofluoresein diacetate (CM-H{sub 2}-DCFDA) fluorometry, and p53-related protein expression by Western blotting. E was found to have a radio-protective effect on cells at high concentrations (e.g., 2.7 and 3 mg/mL, 2Gy) and radio-sensitizing action at low concentrations (e.g., 0.15-1.5 mg/mL). Clinical plasma levels of E have been reportedly far lower than the concentrations in this experiment: ideally, E can sensitize tumor cells to radiation and protect normal cells from. (K.T.)

  20. Modification of radiation sensitivity by edaravone

    International Nuclear Information System (INIS)

    Sasano, Nakashi; Enomoto, Atsushi; Miyagawa, Kiyoshi; Hosoi, Yoshio; Nakagawa, Keiichi

    2009-01-01

    Studied was the effect of edaravone (E), a clinical therapeutic drug for brain infarction possessing properties of free radical scavenger, on apoptosis in vitro. Human T-cell leukemic MOLT-4 cells and p53-knockdown MOLT-4 cells which overexpressing short hairpin type p53 by siRNA treatment were X-irradiated by Shimadzu Pantak HF 350 machine at 135-140 cGy/min for 2-5 Gy in total, in the presence of E. Cell death was estimated by dye-exclusion, apoptosis by EPICS flow cytometry, cellular reactive oxygen species by chloromethyl-2',7'-dichlorodihydrofluoresein diacetate (CM-H 2 -DCFDA) fluorometry, and p53-related protein expression by Western blotting. E was found to have a radio-protective effect on cells at high concentrations (e.g., 2.7 and 3 mg/mL, 2Gy) and radio-sensitizing action at low concentrations (e.g., 0.15-1.5 mg/mL). Clinical plasma levels of E have been reportedly far lower than the concentrations in this experiment: ideally, E can sensitize tumor cells to radiation and protect normal cells from. (K.T.)

  1. Incidence of radiation-induced Graves' disease in patients treated with radioiodine for thyroid autonomy before and after introduction of a high-sensitivity TSH receptor antibody assay

    International Nuclear Information System (INIS)

    Dunkelmann, Simone; Wolf, Ricarda; Koch, Annedore; Kittner, Christian; Groth, Peter; Schuemichen, Carl

    2004-01-01

    Autoimmune hyperthyroidism may occur several months after radioiodine therapy (RIT) for functional thyroid autonomy. Exacerbation of pre-existing subclinical Graves' disease (GD) has been held responsible for this phenomenon. Determination of TSH receptor antibody using solubilised porcine epithelial cell membranes is insensitive and may have failed to diagnose GD in these patients before RIT. Following the introduction of a more sensitive assay, using the human TSH receptor as an antigen, it has been expected that the incidence of radiation-induced GD after RIT for functional thyroid autonomy will be reduced. In a first group of 1,428 patients treated between November 1993 and March 1997 (group I) we used the porcine TRAb assay to exclude GD, while in a second group comprising 1,408 patients treated between January 2000 and December 2001 (group II), GD was excluded using the human TRAb assay. A matched control group of 231 patients was derived from group II. In group I a total of 15 (1.05%) patients developed obvious or suspected radiation-induced GD, while in group II 17 (1.2%) did so; the interval until development of GD was 8.4 and 8.8 months, respectively, after RIT. Serum anti-thyroid peroxidase levels before RIT were elevated in 36.4% of group I patients and 47.1% of group II patients, but in only 5.6% of the control group. Other non-specific signs of mild immunopathy of the thyroid were seen retrospectively in 73.3%, 64.7% and 16.0% of the patients in these three groups, respectively. In conclusion, the introduction of a high-sensitivity TRAb assay did not reduce the incidence of autoimmune hyperthyroidism occurring late after RIT for functional thyroid autonomy, but mild immunopathy of the thyroid is seen more frequently in these patients and seems to be a predisposing factor in the development of radiation-induced GD. (orig.)

  2. Metal-containing radiation-sensitive polymers

    International Nuclear Information System (INIS)

    Lee, A.Y.

    1986-01-01

    The copolymers of methyl methacrylate with alkali metal salts (Na, K, and Cs) of methacrylic acid have been prepared by saponification K, and Cs) of methylacrylic acid have been prepared by saponification of the homopolymer poly(methyl methacrylate), PMMA. Low degrees of hydrolysis have been achieved by a heterogeneous system, and from the infrared spectra it has been confirmed that the ester groups of the methyl methacrylates are directly converted to the metal salts of methacrylic acid. These ionomers exhibit pseudo high molecular weights in gel permeation chromatogram, but no appreciable increase in intrinsic viscosities is observed in comparison to PMMA. The coordinated inorganic polymers poly[(dithio-2,2'-diacetato)bis(dimethylsulfoxide)dioxouranium(VI)] and poly[{methylenebis(thio)-2,2'-bis(acetato)}bis(dimethylsulfoxide)dioxouranium(VI)]have been synthesized in dimethyl sulfoxide solution with about 90% yield. The degree of polymerization and the number of average molecular weights of these polymers have been assessed by high resolution nuclear magnetic resonance, with which the acetato end group to the bridging ligand group ratios have been determined. The polymers bridging ligand group ratios have been determined. The polymers have been characterized by employing various techniques: infrared spectra, thermal gravimetric analysis, 13 C solid state nuclear magnetic resonance, and gel permeation chromatography. The prepared polymer samples have been subjected to various doses of 137 Cs gamma radiation under which the polymers predominantly undergo chain scission. The radiation sensitivities of the polymers are assessed by G values which are obtained from gel permeation chromatograms. These uranyl polymers exhibit unusually high G values

  3. Radiation polymerized hot melt pressure sensitive adhesives

    International Nuclear Information System (INIS)

    Pastor, S.D.; Skoultchi, M.M.

    1977-01-01

    Hot melt pressure sensitive adhesive compositions formed by copolymerizing at least one 3-(chlorinated aryloxy)-2-hydroxypropyl ester of an alpha, beta unsaturated carboxylic acid with acrylate based copolymerizable monomers, are described. The resultant ethylenically saturated prepolymer is heated to a temperature sufficient to render it fluid and flowable. This composition is coated onto a substrate and exposed to ultraviolet radiation

  4. Novel concepts in modification of radiation sensitivity

    International Nuclear Information System (INIS)

    Bump, E.A.; Palayoor, S.T.; Lai, L.L.; Cerce, B.A.; Langley, R.E.; Coleman, C.N.; Braunhut, S.J.

    1994-01-01

    The purpose of this study was to determine whether biological effects of radiation, such as apoptosis, that differ from classical clonogenic cell killing, can be modified with agents that would not be expected to modify classical clonogenic cell killing. This would expand the range of potential modifiers of radiation therapy. EL4 murine lymphoma cell apoptosis was determined by electrophoretic analysis of deoxyribonucleic acid (DNA) fragmentation. DNA was extracted 24 h after irradiation or addition of inducing agents. Modifiers of radiation-induced apoptosis were added immediately after irradiation. The effects of radiation on wounded endothelial monolayers were studied by scraping a line across the monolayer 30 min after irradiation. Cell detachment was used as an endpoint to determine the protective effect of prolonged exposure to retinol prior to irradiation. EL4 cell apoptosis can be induced by tert-butyl hydroperoxide or the glutathione oxidant SR-4077. Radiation-induced EL4 cell apoptosis can be inhibited with 3-aminobenzamide, an agent that sensitizes cells to classical clonogenic cell killing. Radiation-induced endothelial cell detachment from confluent monolayers can be modified by pretreatment with retinol. These results raise the possibility that radiation could induce apoptosis by an oxidative stress mechanism that is different from that involved in classical clonogenic cell killing. These and other recent findings encourage the notion that differential modification of classical clonogenic cell killing and other important endpoints of radiation action may be possible. 47 refs., 3 figs

  5. Physical determinants of radiation sensitivity in bacterial spores

    International Nuclear Information System (INIS)

    Powers, E.L.

    1982-01-01

    Several factors modifying radiation sensitivity in dry bacterial spores are described and discussed. Vacuum inducing the loss of critical structural water, very low dose rates of radiation from which the cell may recover, radiations of high linear energy transfer, and the action of temperature over long periods of time on previously irradiated cells are recognized from extensive laboratory work as important in determining survival of spores exposed to low radiation doses at low temperatures for long periods of time. Some extensions of laboratory work are proposed

  6. Unique proteomic signature for radiation sensitive patients; a comparative study between normo-sensitive and radiation sensitive breast cancer patients

    Energy Technology Data Exchange (ETDEWEB)

    Skiöld, Sara [Center for Radiation Protection Research, Department of Molecular Biosciences, The Wernner-Gren Institute, Stockholm University, Stockholm (Sweden); Azimzadeh, Omid [Institute of Radiation Biology, German Research Center for Environmental Health, Helmholtz Zentrum München (Germany); Merl-Pham, Juliane [Research Unit Protein Science, German Research Center for Environmental Health, Helmholtz Zentrum München, Neuherberg (Germany); Naslund, Ingemar; Wersall, Peter; Lidbrink, Elisabet [Division of Radiotherapy, Radiumhemmet, Karolinska University Hospital, Stockholm (Sweden); Tapio, Soile [Institute of Radiation Biology, German Research Center for Environmental Health, Helmholtz Zentrum München (Germany); Harms-Ringdahl, Mats [Center for Radiation Protection Research, Department of Molecular Biosciences, The Wernner-Gren Institute, Stockholm University, Stockholm (Sweden); Haghdoost, Siamak, E-mail: Siamak.Haghdoost@su.se [Center for Radiation Protection Research, Department of Molecular Biosciences, The Wernner-Gren Institute, Stockholm University, Stockholm (Sweden)

    2015-06-15

    Highlights: • The unique protein expression profiles were found that separate radiosensitive from normal sensitive breast cancer patients. • The oxidative stress response, coagulation properties and acute phase response suggested to be the hallmarks of radiation sensitivity. - Abstract: Radiation therapy is a cornerstone of modern cancer treatment. Understanding the mechanisms behind normal tissue sensitivity is essential in order to minimize adverse side effects and yet to prevent local cancer reoccurrence. The aim of this study was to identify biomarkers of radiation sensitivity to enable personalized cancer treatment. To investigate the mechanisms behind radiation sensitivity a pilot study was made where eight radiation-sensitive and nine normo-sensitive patients were selected from a cohort of 2914 breast cancer patients, based on acute tissue reactions after radiation therapy. Whole blood was sampled and irradiated in vitro with 0, 1, or 150 mGy followed by 3 h incubation at 37 °C. The leukocytes of the two groups were isolated, pooled and protein expression profiles were investigated using isotope-coded protein labeling method (ICPL). First, leukocytes from the in vitro irradiated whole blood from normo-sensitive and extremely sensitive patients were compared to the non-irradiated controls. To validate this first study a second ICPL analysis comparing only the non-irradiated samples was conducted. Both approaches showed unique proteomic signatures separating the two groups at the basal level and after doses of 1 and 150 mGy. Pathway analyses of both proteomic approaches suggest that oxidative stress response, coagulation properties and acute phase response are hallmarks of radiation sensitivity supporting our previous study on oxidative stress response. This investigation provides unique characteristics of radiation sensitivity essential for individualized radiation therapy.

  7. Unique proteomic signature for radiation sensitive patients; a comparative study between normo-sensitive and radiation sensitive breast cancer patients

    International Nuclear Information System (INIS)

    Skiöld, Sara; Azimzadeh, Omid; Merl-Pham, Juliane; Naslund, Ingemar; Wersall, Peter; Lidbrink, Elisabet; Tapio, Soile; Harms-Ringdahl, Mats; Haghdoost, Siamak

    2015-01-01

    Highlights: • The unique protein expression profiles were found that separate radiosensitive from normal sensitive breast cancer patients. • The oxidative stress response, coagulation properties and acute phase response suggested to be the hallmarks of radiation sensitivity. - Abstract: Radiation therapy is a cornerstone of modern cancer treatment. Understanding the mechanisms behind normal tissue sensitivity is essential in order to minimize adverse side effects and yet to prevent local cancer reoccurrence. The aim of this study was to identify biomarkers of radiation sensitivity to enable personalized cancer treatment. To investigate the mechanisms behind radiation sensitivity a pilot study was made where eight radiation-sensitive and nine normo-sensitive patients were selected from a cohort of 2914 breast cancer patients, based on acute tissue reactions after radiation therapy. Whole blood was sampled and irradiated in vitro with 0, 1, or 150 mGy followed by 3 h incubation at 37 °C. The leukocytes of the two groups were isolated, pooled and protein expression profiles were investigated using isotope-coded protein labeling method (ICPL). First, leukocytes from the in vitro irradiated whole blood from normo-sensitive and extremely sensitive patients were compared to the non-irradiated controls. To validate this first study a second ICPL analysis comparing only the non-irradiated samples was conducted. Both approaches showed unique proteomic signatures separating the two groups at the basal level and after doses of 1 and 150 mGy. Pathway analyses of both proteomic approaches suggest that oxidative stress response, coagulation properties and acute phase response are hallmarks of radiation sensitivity supporting our previous study on oxidative stress response. This investigation provides unique characteristics of radiation sensitivity essential for individualized radiation therapy

  8. Immunological aspects of light radiation sensitivity

    International Nuclear Information System (INIS)

    Hellman, K.B.; Schuller, G.B.

    1981-01-01

    The immune system comprises one aspect of the host's defense mechanism against potentially harmful agents. It has become recognized as an important factor in light radiation sensitivity and light-mediated disease. The interaction of light radiation with the immune system has formed the basis for the evolving discipline of photoimmunology. A description of the multicomponent immune system, its modification by light radiation, and a discussion of how photoimmunological studies may provide data important for understanding the mechanisms involved in photosensitivity are presented in this review. Photosensitivity may be either acquired or may be genetic in nature. Acquired photosensitivity involves an individual's reaction to either light alone or light in conjunction with topically or systemically administered photosenitizing agents. The outcome of such a reaction can be benign or severe, depending on a number of factors. Genetic photosensitivity includes the reactions to light radiation of individuals carrying the genetic information for inherited diseases such as Ataxia telangiectasia (AT) and Xeroderma pigmentosum (XP). Factors associated with these conditions can lead to enhanced sensitivity to radiation-related diseases, such as cancer. In addition, there are conditions which cannot be readily placed in either of the categories just described but, nevertheless, have been correlated with immune system dysfunction. These include photoallergy, photosensitivity associated with autoimmunity, and light-induced skin cancer. Immunological studies have provided information which may aid in elucidating the problem of photosensitivity and in the development of suitable radioprotective measures

  9. Development of an ionization chamber based high sensitivity detector for the measurement of radiation dose from X-ray whole body scanners

    International Nuclear Information System (INIS)

    Singh, Sunil K.; Tripathi, S.M.; LijiShaiju; Sathian, V.; Kulkarni, M.S.

    2016-01-01

    Using walk through metal detectors and undergoing frisking for personals at airports, seaports, railway stations and other sensitive places no longer meets proper security requirements. Now a days use of plastic explosives, drug trafficking or illegal carriage of dangerous items concealed under cloths or body cavities has increased many folds which in many cases is not possible to detect by conventional methods. One of the systems which are capable to overcome the above mentioned difficulties is the use of X-ray based whole body scanners, either transmission type or backscatter type, depending upon the nature of requirement. While using these whole body scanners the person being scanned possesses a radiation risk whose safety aspects can be monitored by following international standards (recommending certain dose limits). In order to check the compliance of these dose limits, the dose per scan received by the person (from these whole body scanners) needs to be measured. A very high sensitive ionization chamber has been designed and fabricated for measuring these extremely low X- ray fields ( few μR) produced by a scanning X-ray beam over a large area. A methodology has been developed to measure exposure per scan using large volume ionization chambers. This value of exposure was used to calculate whole body dose as per the recommendations of ANSI standard for its compliance

  10. Radiation sensitivity of human malignant lymphocytes

    International Nuclear Information System (INIS)

    Seshadri, R.; Matthews, C.; Morley, A.A.

    1985-01-01

    A simple and rapid in vitro technique to assess the sensitivity of human malignant lymphocytes to roentgen irradiation is described. A variety of established malignant lymphocyte cell lines were cloned in microwells and clone survival was used as the end-point. The survival of the clonogenic malignant lymphocyte down to a fraction of approximately 0.001 could be measured accurately. Except for a T-cell line, the radiation sensitivities of the cell lines were similar to that of normal T-lymphocytes. (orig.)

  11. Individual radiation sensitivity: implications in medical practice

    Energy Technology Data Exchange (ETDEWEB)

    Gisone, P.; Dubner, D.; Perez, M.D.R.; Michelin, S.; Di Giogio, M. [Autoridad Regulatoria Nuclear, Buenos Aires (Argentina); Bourguignon, M. [Direction Generale de la Surete Nucleaire et de la Radioprotection, Paris (France)

    2006-07-01

    Important advances in radiotherapy and nuclear medicine towards better treatment modalities and safer applications have taken place in recent years. Progress in medical imaging, better tumour targeting and optimization of radiation delivery have allowed for dose escalation and improved patient outcome. However, the tolerance of normal tissues constitutes the limiting factor for dose escalation in therapeutical uses of ionizing radiation (IR). Patients vary considerably in their normal tissue response to IR even after similar treatments. As many as 5% of cancer patients develop severe effects to external radiation therapy in normal tissues within the treatment field: they may include acute effects such as erythema and desquamation of the exposed skin and mucosa that appear during or directly after radiotherapy, late effects developed months or years later, such as fibrosis and telangiectasia and cancer induction. Several patient and treatment related factors are known to influence the variability of side effects, however up to a 70% of the total variance of normal tissue radiation response remained unexplained. Thus, individual sensitivity to IR, i.e. hypersensitivity to carcinogenic risks (stochastic effects) and hypersensitivity to deterministic effects, is becoming an important issue in oncology and raises questions regarding the underlying mechanisms. The mechanisms of DNA repair, the signalling pathways involved in radiation sensitivity and non-targeted effects are key aspects, essential to understanding radiation effects at genetic level. Moreover, human genetic diseases that combine higher incidence of cancer and hypersensitivity to IR are associated with defects in cell response to DNA damage. Therefore, much interest has raised during the last years in the developing of predictive tests capable to detect in advance such hypersensitive conditions. The goal of this presentation is to review the possible mechanisms involved in genetic and epigenetic

  12. Individual radiation sensitivity: implications in medical practice

    International Nuclear Information System (INIS)

    Gisone, P.; Dubner, D.; Perez, M.D.R.; Michelin, S.; Di Giogio, M.; Bourguignon, M.

    2006-01-01

    Important advances in radiotherapy and nuclear medicine towards better treatment modalities and safer applications have taken place in recent years. Progress in medical imaging, better tumour targeting and optimization of radiation delivery have allowed for dose escalation and improved patient outcome. However, the tolerance of normal tissues constitutes the limiting factor for dose escalation in therapeutical uses of ionizing radiation (IR). Patients vary considerably in their normal tissue response to IR even after similar treatments. As many as 5% of cancer patients develop severe effects to external radiation therapy in normal tissues within the treatment field: they may include acute effects such as erythema and desquamation of the exposed skin and mucosa that appear during or directly after radiotherapy, late effects developed months or years later, such as fibrosis and telangiectasia and cancer induction. Several patient and treatment related factors are known to influence the variability of side effects, however up to a 70% of the total variance of normal tissue radiation response remained unexplained. Thus, individual sensitivity to IR, i.e. hypersensitivity to carcinogenic risks (stochastic effects) and hypersensitivity to deterministic effects, is becoming an important issue in oncology and raises questions regarding the underlying mechanisms. The mechanisms of DNA repair, the signalling pathways involved in radiation sensitivity and non-targeted effects are key aspects, essential to understanding radiation effects at genetic level. Moreover, human genetic diseases that combine higher incidence of cancer and hypersensitivity to IR are associated with defects in cell response to DNA damage. Therefore, much interest has raised during the last years in the developing of predictive tests capable to detect in advance such hypersensitive conditions. The goal of this presentation is to review the possible mechanisms involved in genetic and epigenetic

  13. Albendazole sensitizes cancer cells to ionizing radiation

    International Nuclear Information System (INIS)

    Patel, Kirtesh; Doudican, Nicole A; Schiff, Peter B; Orlow, Seth J

    2011-01-01

    Brain metastases afflict approximately half of patients with metastatic melanoma (MM) and small cell lung cancer (SCLC) and represent the direct cause of death in 60 to 70% of those affected. Standard of care remains ineffective in both types of cancer with the challenge of overcoming the blood brain barrier (BBB) exacerbating the clinical problem. Our purpose is to determine and characterize the potential of albendazole (ABZ) as a cytotoxic and radiosensitizing agent against MM and SCLC cells. Here, ABZ's mechanism of action as a DNA damaging and microtubule disrupting agent is assessed through analysis of histone H2AX phosphorylation and cell cyle progression. The cytotoxicity of ABZ alone and in combination with radiation therapy is determined though clonogenic cell survival assays in a panel of MM and SCLC cell lines. We further establish ABZ's ability to act synergistically as a radio-sensitizer through combination index calculations and apoptotic measurements of poly (ADP-ribose) polymerase (PARP) cleavage. ABZ induces DNA damage as measured by increased H2AX phosphorylation. ABZ inhibits the growth of MM and SCLC at clinically achievable plasma concentrations. At these concentrations, ABZ arrests MM and SCLC cells in the G2/M phase of the cell cycle after 12 hours of treatment. Exploiting the notion that cells in the G2/M phase are the most sensitive to radiation therapy, we show that treatment of MM and SCLC cells treated with ABZ renders them more sensitive to radiation in a synergistic fashion. Additionally, MM and SCLC cells co-treated with ABZ and radiation exhibit increased apoptosis at 72 hours. Our study suggests that the orally available antihelminthic ABZ acts as a potent radiosensitizer in MM and SCLC cell lines. Further evaluation of ABZ in combination with radiation as a potential treatment for MM and SCLC brain metastases is warranted

  14. Albendazole sensitizes cancer cells to ionizing radiation

    Science.gov (United States)

    2011-01-01

    Background Brain metastases afflict approximately half of patients with metastatic melanoma (MM) and small cell lung cancer (SCLC) and represent the direct cause of death in 60 to 70% of those affected. Standard of care remains ineffective in both types of cancer with the challenge of overcoming the blood brain barrier (BBB) exacerbating the clinical problem. Our purpose is to determine and characterize the potential of albendazole (ABZ) as a cytotoxic and radiosensitizing agent against MM and SCLC cells. Methods Here, ABZ's mechanism of action as a DNA damaging and microtubule disrupting agent is assessed through analysis of histone H2AX phosphorylation and cell cyle progression. The cytotoxicity of ABZ alone and in combination with radiation therapy is determined though clonogenic cell survival assays in a panel of MM and SCLC cell lines. We further establish ABZ's ability to act synergistically as a radio-sensitizer through combination index calculations and apoptotic measurements of poly (ADP-ribose) polymerase (PARP) cleavage. Results ABZ induces DNA damage as measured by increased H2AX phosphorylation. ABZ inhibits the growth of MM and SCLC at clinically achievable plasma concentrations. At these concentrations, ABZ arrests MM and SCLC cells in the G2/M phase of the cell cycle after 12 hours of treatment. Exploiting the notion that cells in the G2/M phase are the most sensitive to radiation therapy, we show that treatment of MM and SCLC cells treated with ABZ renders them more sensitive to radiation in a synergistic fashion. Additionally, MM and SCLC cells co-treated with ABZ and radiation exhibit increased apoptosis at 72 hours. Conclusions Our study suggests that the orally available antihelminthic ABZ acts as a potent radiosensitizer in MM and SCLC cell lines. Further evaluation of ABZ in combination with radiation as a potential treatment for MM and SCLC brain metastases is warranted. PMID:22094106

  15. Radiation curable pressure sensitive adhesive composition

    International Nuclear Information System (INIS)

    Steuben, K.C.

    1978-01-01

    Radiation curable pressure sensitive adhesive composition comprises: a polyoxyalkylene homo- or copolymer which is either a polyoxyethylene homopolymer or a poly (oxyethylene-oxypropylene) copolymer, or mixture thereof, having a molecular weight of from 1,700 to 90,000, in which at least 40 percent by weight of the oxyalkylene units are oxyethylene units; a liquid carbamyloxy alkyl acrylate; and, optionally, a photoinitiator

  16. Radiation-induced Genomic Instability and Radiation Sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Varnum, Susan M.; Sowa, Marianne B.; Kim, Grace J.; Morgan, William F.

    2013-01-19

    The obvious relationships between reactive oxygen and nitrogen species, mitochondrial dysfunction, inflammatory type responses and reactive chemokines and cytokines suggests a general stress response induced by ionizing radiation most likely leads to the non-targeted effects described after radiation exposure. We argue that true bystander effects do not occur in the radiation therapy clinic. But there is no question that effects outside the target volume do occur. These “out of field effects” are considered very low dose effects in the context of therapy. So what are the implications of non-targeted effects on radiation sensitivity? The primary goal of therapy is to eradicate the tumor. Given the genetic diversity of the human population, lifestyle and environment factors it is likely some combination of these will influence patient outcome. Non-targeted effects may contribute to a greater or lesser extent. But consider the potential situation involving a partial body exposure due to a radiation accident or radiological terrorism. Non-targeted effects suggest that the tissue at risk for demonstrating possible detrimental effects of radiation exposure might be greater than the volume actually irradiated.

  17. In vivo radiation sensitivity of glioblastoma multiforme

    International Nuclear Information System (INIS)

    Taghian, Alphonse; Freeman, Jill; Suit, Herman; DuBois, Willem; Budach, Wilfried; Baumann, Michael

    1995-01-01

    Purpose: Human glioblastoma (GBM) is one of the most resistant tumors to radiation. In previous reports, we have demonstrated a wide range of radiation sensitivity of GBM in vitro; that is, SF 2 values of 0.2 to 0.8. The great sensitivity of some of the cell lines is not in accord with the almost invariably fatal clinical outcome of patients with GBM. The sensitivity of cells in vitro pertains to cells cultured in optimal nutritional conditions. The TCD 50 (the radiation dose necessary to control 50% of the tumors locally) determined in lab animals is analogous to the use of radiation with curative intent in clinical radiation oncology. The aim of the present study was (a) to evaluate the sensitivity of GBM in vivo relative to that of other tumor types and (b) assess the relationship between the single dose TCD 50 of the xenografts and the sensitivity of the corresponding cell lines in vitro. Methods and Materials: The TCD 50 assay was used to study twelve human tumor lines. Four previously published values were added. A total of 10 GBM, 4 squamous cell carcinoma (SCC), 1 soft tissue sarcoma (STS), and 1 cancer colon (CC) are included in the analysis. For further suppression of the residual immune system, all the animals received 6 Gy whole-body irradiation 1 day before transplantation. Local tumor irradiations were given as a single dose, under conditions of clamp hypoxia using a Cs irradiator. Results: The TCD 50 values for the 10 GBM xenografts varied between 32.5 and 75.2 Gy, with an average of 47.2 ± 13.1 Gy. The TCD 50 values for the SCC were similar to those of the GBM and ranged from 40.7 and 54.4 Gy, with a mean of 46.8 ± 6.4. The difference between the average TCD 50 of GBM and SCC was not significant. The STS and CC xenografts had TCD 50 values of 46.0 and 49.2 Gy, respectively. No correlation was found between the TCD 50 in vivo and the SF 2 or D 0 in vitro. Conclusions: Our data on GBM xenografts showed a wide range of sensitivities to single dose

  18. In vivo radiation sensitivity of glioblastoma multiforme

    Energy Technology Data Exchange (ETDEWEB)

    Taghian, Alphonse; Freeman, Jill; Suit, Herman; DuBois, Willem; Budach, Wilfried; Baumann, Michael

    1995-04-30

    Purpose: Human glioblastoma (GBM) is one of the most resistant tumors to radiation. In previous reports, we have demonstrated a wide range of radiation sensitivity of GBM in vitro; that is, SF{sub 2} values of 0.2 to 0.8. The great sensitivity of some of the cell lines is not in accord with the almost invariably fatal clinical outcome of patients with GBM. The sensitivity of cells in vitro pertains to cells cultured in optimal nutritional conditions. The TCD{sub 50} (the radiation dose necessary to control 50% of the tumors locally) determined in lab animals is analogous to the use of radiation with curative intent in clinical radiation oncology. The aim of the present study was (a) to evaluate the sensitivity of GBM in vivo relative to that of other tumor types and (b) assess the relationship between the single dose TCD{sub 50} of the xenografts and the sensitivity of the corresponding cell lines in vitro. Methods and Materials: The TCD{sub 50} assay was used to study twelve human tumor lines. Four previously published values were added. A total of 10 GBM, 4 squamous cell carcinoma (SCC), 1 soft tissue sarcoma (STS), and 1 cancer colon (CC) are included in the analysis. For further suppression of the residual immune system, all the animals received 6 Gy whole-body irradiation 1 day before transplantation. Local tumor irradiations were given as a single dose, under conditions of clamp hypoxia using a Cs irradiator. Results: The TCD{sub 50} values for the 10 GBM xenografts varied between 32.5 and 75.2 Gy, with an average of 47.2 {+-} 13.1 Gy. The TCD{sub 50} values for the SCC were similar to those of the GBM and ranged from 40.7 and 54.4 Gy, with a mean of 46.8 {+-} 6.4. The difference between the average TCD{sub 50} of GBM and SCC was not significant. The STS and CC xenografts had TCD{sub 50} values of 46.0 and 49.2 Gy, respectively. No correlation was found between the TCD{sub 50} in vivo and the SF{sub 2} or D{sub 0} in vitro. Conclusions: Our data on GBM

  19. Investigation of graphene-based nanoscale radiation sensitive materials

    Science.gov (United States)

    Robinson, Joshua A.; Wetherington, Maxwell; Hughes, Zachary; LaBella, Michael, III; Bresnehan, Michael

    2012-06-01

    Current state-of-the-art nanotechnology offers multiple benefits for radiation sensing applications. These include the ability to incorporate nano-sized radiation indicators into widely used materials such as paint, corrosion-resistant coatings, and ceramics to create nano-composite materials that can be widely used in everyday life. Additionally, nanotechnology may lead to the development of ultra-low power, flexible detection systems that can be embedded in clothing or other systems. Graphene, a single layer of graphite, exhibits exceptional electronic and structural properties, and is being investigated for high-frequency devices and sensors. Previous work indicates that graphene-oxide (GO) - a derivative of graphene - exhibits luminescent properties that can be tailored based on chemistry; however, exploration of graphene-oxide's ability to provide a sufficient change in luminescent properties when exposed to gamma or neutron radiation has not been carried out. We investigate the mechanisms of radiation-induced chemical modifications and radiation damage induced shifts in luminescence in graphene-oxide materials to provide a fundamental foundation for further development of radiation sensitive detection architectures. Additionally, we investigate the integration of hexagonal boron nitride (hBN) with graphene-based devices to evaluate radiation induced conductivity in nanoscale devices. Importantly, we demonstrate the sensitivity of graphene transport properties to the presence of alpha particles, and discuss the successful integration of hBN with large area graphene electrodes as a means to provide the foundation for large-area nanoscale radiation sensors.

  20. A radiation research apparatus sensitive to wavelength

    International Nuclear Information System (INIS)

    1980-01-01

    The apparatus described is equipped with a radiation source with a tuning device for the generation of X radiation of at least two different wavelength spectra. The detector with ionisation chamber is able to discriminate between these spectra. This is done with the aid of an auxillary electrode between the entrance window and a high voltage electrode. With a lower source of voltage this electrode has a potential equal to the high voltage electrode potential and with a higher voltage source it has a potential equal to the signal electrode potential. (Th.P.)

  1. Role of mitochondria in radiation sensitivity

    International Nuclear Information System (INIS)

    Indo, Hiroko; Tomita, Kazuo; Majima, Hideyuki; Matsui, Hirofumi; Ozawa, Toshihiko

    2007-01-01

    This paper describes mainly the role of mitochondrial (Mt) manganese superoxide dismutase (MnSOD) for deciding the radiation sensitivity of cells. The fact that Mt concerns with apoptosis has been shown by the finding that change in Mt membrane potential relates with the cell death. Mt has the electron transport system to yield the cellular energy molecule (ATP) and from which electrons are leaked out in 2-3%, a considerably large proportion in a cell. The electrons react with oxygen nearby to yield SO (O 2 ·- ), which in turn induces apoptosis through oxidation stress (OS). On the other hand, MnSOD is transported in Mt from cytoplasm and excludes the reactive oxygen species (ROS) like SO. Studies by MnSOD gene-deletion, knockout, cDNA-transfection, and transgenesis have indicated MnSOD is essential for keeping life and resistance to OS. Authors have shown that overexpression of Mt MnSOD protects against radiation-induced cell death, suggesting that Mt participates in radiation sensitivity where SO is involved. Interestingly, MnSOD activity is low in cancer cells, its overexpression results in tumor suppression and MnSOD is a target in leukemia therapy. When MTS (Mt targeting sequence, necessary for the enzyme to enter Mt)-deleted MnSOD is transfected, cells lack resistance to radiation, indicating the enzyme must be present in Mt. Mt DNA damage leading to electron transport system impairment is found to increase ROS, and to be reversed by the transfection of MnSOD gene. Studies of Mt DNA damage in cancer cells where aerobic glycolysis is actively operated, are currently in progress lively, and are thought to promote the development of diagnosis and treatment of cancer. (R.T.)

  2. Differential sensitivity of Chironomus and human hemoglobin to gamma radiation

    International Nuclear Information System (INIS)

    Gaikwad, Pallavi S.; Panicker, Lata; Mohole, Madhura; Sawant, Sangeeta; Mukhopadhyaya, Rita; Nath, Bimalendu B.

    2016-01-01

    Chironomus ramosus is known to tolerate high doses of gamma radiation exposure. Larvae of this insect possess more than 95% of hemoglobin (Hb) in its circulatory hemolymph. This is a comparative study to see effect of gamma radiation on Hb of Chironomus and humans, two evolutionarily diverse organisms one having extracellular and the other intracellular Hb respectively. Stability and integrity of Chironomus and human Hb to gamma radiation was compared using biophysical techniques like Dynamic Light Scattering (DLS), UV-visible spectroscopy, fluorescence spectrometry and CD spectroscopy after exposure of whole larvae, larval hemolymph, human peripheral blood, purified Chironomus and human Hb. Sequence- and structure-based bioinformatics methods were used to analyze the sequence and structural similarities or differences in the heme pockets of respective Hbs. Resistivity of Chironomus Hb to gamma radiation is remarkably higher than human Hb. Human Hb exhibited loss of heme iron at a relatively low dose of gamma radiation exposure as compared to Chironomus Hb. Unlike human Hb, the heme pocket of Chironomus Hb is rich in aromatic amino acids. Higher hydophobicity around heme pocket confers stability of Chironomus Hb compared to human Hb. Previously reported gamma radiation tolerance of Chironomus can be largely attributed to its evolutionarily ancient form of extracellular Hb as evident from the present study. -- Highlights: •Comparison of radiation tolerant Chironomus Hb and radiation sensitive Human Hb. •Amino acid composition of midge and human heme confer differential hydrophobicity. •Heme pocket of evolutionarily ancient midge Hb provide gamma radiation resistivity.

  3. Differential sensitivity of Chironomus and human hemoglobin to gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Gaikwad, Pallavi S. [Stress Biology Research Laboratory, Department of Zoology, Savitribai Phule University, Pune, 411007 (India); Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085 (India); Panicker, Lata [Solid State Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085 (India); Mohole, Madhura; Sawant, Sangeeta [Bioinformatics Center, Savitribai Phule Pune University, Pune, 411007 (India); Mukhopadhyaya, Rita [Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085 (India); Nath, Bimalendu B., E-mail: bbnath@gmail.com [Stress Biology Research Laboratory, Department of Zoology, Savitribai Phule University, Pune, 411007 (India)

    2016-08-05

    Chironomus ramosus is known to tolerate high doses of gamma radiation exposure. Larvae of this insect possess more than 95% of hemoglobin (Hb) in its circulatory hemolymph. This is a comparative study to see effect of gamma radiation on Hb of Chironomus and humans, two evolutionarily diverse organisms one having extracellular and the other intracellular Hb respectively. Stability and integrity of Chironomus and human Hb to gamma radiation was compared using biophysical techniques like Dynamic Light Scattering (DLS), UV-visible spectroscopy, fluorescence spectrometry and CD spectroscopy after exposure of whole larvae, larval hemolymph, human peripheral blood, purified Chironomus and human Hb. Sequence- and structure-based bioinformatics methods were used to analyze the sequence and structural similarities or differences in the heme pockets of respective Hbs. Resistivity of Chironomus Hb to gamma radiation is remarkably higher than human Hb. Human Hb exhibited loss of heme iron at a relatively low dose of gamma radiation exposure as compared to Chironomus Hb. Unlike human Hb, the heme pocket of Chironomus Hb is rich in aromatic amino acids. Higher hydophobicity around heme pocket confers stability of Chironomus Hb compared to human Hb. Previously reported gamma radiation tolerance of Chironomus can be largely attributed to its evolutionarily ancient form of extracellular Hb as evident from the present study. -- Highlights: •Comparison of radiation tolerant Chironomus Hb and radiation sensitive Human Hb. •Amino acid composition of midge and human heme confer differential hydrophobicity. •Heme pocket of evolutionarily ancient midge Hb provide gamma radiation resistivity.

  4. Radiation-sensitive genetically susceptible pediatric sub-populations

    Energy Technology Data Exchange (ETDEWEB)

    Kleinerman, Ruth A. [National Cancer Institute, NIH, DHHS, Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, Rockville, MD (United States)

    2009-02-15

    Major advances in pediatric cancer treatment have resulted in substantial improvements in survival. However, concern has emerged about the late effects of cancer therapy, especially radiation-related second cancers. Studies of childhood cancer patients with inherited cancer syndromes can provide insights into the interaction between radiation and genetic susceptibility to multiple cancers. Children with retinoblastoma (Rb), neurofibromatosis type 1 (NF1), Li-Fraumeni syndrome (LFS), and nevoid basal cell carcinoma syndrome (NBCCS) are at substantial risk of developing radiation-related second and third cancers. A radiation dose-response for bone and soft-tissue sarcomas has been observed in hereditary Rb patients, with many of these cancers occurring in the radiation field. Studies of NF1 patients irradiated for optic pathway gliomas have reported increased risks of developing another cancer associated with radiotherapy. High relative risks for second and third cancers were observed for a cohort of 200 LFS family members, especially children, possibly related to radiotherapy. Children with NBCCS are very sensitive to radiation and develop multiple basal cell cancers in irradiated areas. Clinicians following these patients should be aware of their increased genetic susceptibility to multiple primary malignancies enhanced by sensitivity to ionizing radiation. (orig.)

  5. High order depletion sensitivity analysis

    International Nuclear Information System (INIS)

    Naguib, K.; Adib, M.; Morcos, H.N.

    2002-01-01

    A high order depletion sensitivity method was applied to calculate the sensitivities of build-up of actinides in the irradiated fuel due to cross-section uncertainties. An iteration method based on Taylor series expansion was applied to construct stationary principle, from which all orders of perturbations were calculated. The irradiated EK-10 and MTR-20 fuels at their maximum burn-up of 25% and 65% respectively were considered for sensitivity analysis. The results of calculation show that, in case of EK-10 fuel (low burn-up), the first order sensitivity was found to be enough to perform an accuracy of 1%. While in case of MTR-20 (high burn-up) the fifth order was found to provide 3% accuracy. A computer code SENS was developed to provide the required calculations

  6. Influence of catalase on the radiation sensitizing effect of misonidazole

    International Nuclear Information System (INIS)

    Gazso, G.L.; Dam, A.

    1985-01-01

    The radiation modifying action of misonidazole and catalase was investigated in Bacillus megaterium spores at various oxygen concentrations. Catalase (120 μg/ml) decreased the radiation sensitizing action of misonidazole. Misonidazole as an electron affinic radiation sensitizer enhanced the build up of H 2 O 2 , thus promoting the reaction with catalase. Protection by catalase was not enough to eliminate the total radiation sensitizing effect of misonidazole. (orig.)

  7. Gamma response study of radiation sensitive MOSFETs for their use as gamma radiation sensor

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Saurabh; Kumar, A. Vinod [Radiation Safety Systems Division, Bhabha Atomic Research Centre, Mumbai (India); Aggarwal, Bharti; Singh, Arvind; Topkar, Anita, E-mail: anita@barc.gov.in [Electronics Division, Bhabha Atomic Research Centre, Mumbai (India)

    2016-05-23

    Continuous monitoring of gamma dose is important in various fields like radiation therapy, space-related research, nuclear energy programs and high energy physics experiment facilities. The present work is focused on utilization of radiation-sensitive Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs) to monitor gamma radiation doses. Static characterization of these detectors was performed to check their expected current-voltage relationship. Threshold voltage and transconductance per unit gate to source voltage (K factor) were calculated from the experimental data. The detector was exposed to gamma radiation in both, with and without gate bias voltage conditions, and change in threshold voltage was monitored at different gamma doses. The experimental data was fitted to obtain equation for dependence of threshold voltage on gamma dose. More than ten times increase in sensitivity was observed in biased condition (+3 V) compared to the unbiased case.

  8. Comparative study of different surrogate markers for individual radiation sensitivity

    International Nuclear Information System (INIS)

    Hoffmann, Nele Julia

    2013-01-01

    Radiotherapy is an important part of therapeutic tumor treatment concept. The applied total dose is limited by the unavoidable radiation effect on the surrounding normal tissue and the risk of radiation induced acute or chronic side effects. The clinical radiation sensitivity, i.e. the risk of radiogenic side effects is strongly coupled to the cellular radiation sensitivity. The contribution is focused on the development of a predictive tool for the individual radiation sensitivity for individual radiotherapeutic planning using lymphocytes. Residual foci, i.e. accumulated repair associated proteins at the residual double strand break are supposed to be surrogate markers of the cellular radiation sensitivity. No relation between the foci detection and the G(0)/G(1) was found assay with respect to the individual radiation sensitivity.

  9. Sensitivity of viruses to radiation sterilization

    International Nuclear Information System (INIS)

    Dziedzic Goclawska; A

    1999-01-01

    The hazard of infectious disease transmission with tissue allografts is a major concern in tissue banking practice. Microorganisms can be introduced into grafts during tissue collection, processing and storage, but even when all these procedures are performed under a septic conditions, the possibility of fungal, bacterial or viral disease transmission of donor origin can not be excluded. Therefore, in order to minimize the risk of infectious disease transmission, several steps should be undertaken, including a careful donor screening, proper tissue processing and sterilization of tissue allografts. The risk of transmission of viral infections such as hepatitis B, C, other viruses and particularly HIV with tissue allografts is of great significance and the search for sterilizing methods which inactivate and/or highly reduce viral infectivity continues. Sterilization of tissue allografts with ionizing radiation (introduced in the mid of 1950s) is increasingly used in tissue banking practice. The effectiveness of the radiation-sterilization procedure depends on the amount of energy transferred, the number of contaminating microorganisms and their resistance to ionizing radiation (initial contamination, bioburden). Usually, spores are more resistant than vegetative forms of bacteria, some fungi may be as resistant as bacterial spores, and viruses are, in general, more resistant than bacteria. Dita concerning effectiveness of ionizing radiation to inactivate viruses (e.g. such as HBV, HCV or HIV) in tissue allografts collected from cadavers are scarce. It has been found that the dose of irradiation needed to reduce HIV load by I log10 unit (D10) is about 4.0 kGy or even 5.6 kGy. The level of infectious HIV in plasma is usually evaluated by titration of tissue culture infective dose (TCID50/ml). Taking into consideration the recommended sterility assurance level (SAL) 10-6, assuming the HIV bioburden to be 103 TCID50/ml for the state of acute infection and D10 value of 4

  10. Radiation-sensitive material and method of recording information upon radiation-sensitive material

    International Nuclear Information System (INIS)

    Petrov, V.V.; Krjuchin, A.A.

    1981-01-01

    The invention can be employed for recording binary information in memory units of electronic computers, in video-recording equipment, laser recording devices and other recording means. The proposed radiation-sensitive material comprises a metallic layer made of silver, or copper, or nickel, or thallium, or alloy thereof, an inorganic material layer made of arsenic chalcogenide, or antimony chalcogenide, or bismuth chalcogenide, and a separation layer disposed between the metallic layer and the inorganic material layer made of a material which is inert relative to said layers, which separation layer has a thickness sufficient for preventing interaction between the metallic layer and the inorganic material layer when the radiation-sensitive materials is exposed to electromagnetic or corpuscular radiation having a power density lower than a threshold value required for the breakdown of the separation layer in the area exposed to radiation. The separation layer can be made from As, Sb, Si or Ge or their oxides, metallic oxides of e.g. Al, Ti, V or Fe, or from polyorganosiloxane films. (author)

  11. Dosimetry of high energy radiation

    CERN Document Server

    Sahare, P D

    2018-01-01

    High energy radiation is hazardous to living beings and a threat to mankind. The correct estimation of the high energy radiation is a must and a single technique may not be very successful. The process of estimating the dose (the absorbed energy that could cause damages) is called dosimetry. This book covers the basic technical knowledge in the field of radiation dosimetry. It also makes readers aware of the dangers and hazards of high energy radiation.

  12. Development of a highly sensitive lithium fluoride thermoluminescence dosimeter

    International Nuclear Information System (INIS)

    Moraes da Silva, Teresinha de; Campos, Leticia Lucente

    1995-01-01

    In recent times, LiF: Mg, Cu, P thermoluminescent phosphor has been increasingly in use for radiation monitoring due its high sensitivity and ease of preparation. The Dosimetric Materials Production Laboratory of IPEN, (Nuclear Energy Institute) has developed a simple method to obtain high sensitivity LiF. The preparation method is described. (author). 4 refs., 1 fig., 1 tab

  13. Sensitivity of transient synchrotron radiation to tokamak plasma parameters

    International Nuclear Information System (INIS)

    Fisch, N.J.; Kritz, A.H.

    1988-12-01

    Synchrotron radiation from a hot plasma can inform on certain plasma parameters. The dependence on plasma parameters is particularly sensitive for the transient radiation response to a brief, deliberate, perturbation of hot plasma electrons. We investigate how such a radiation response can be used to diagnose a variety of plasma parameters in a tokamak. 18 refs., 13 figs

  14. Modification of radiation sensitivity: the oxygen effect

    International Nuclear Information System (INIS)

    Quintiliani, M.

    1979-01-01

    Four fundamental aspects of the oxygen effect in radiobiology are reviewed, with emphasis on single cell systems: (1) Radiosensitivity in relation to oxygen concentration. In many biological systems, this relationship is remarkably well represented by the well-known Howard-Flanders/Alper formula. Often, however, the degree of uncertainty associated with the estimation of the value of K in the formula is fairly high. Recent data on V79-753B cells indicate a biphasic influence of oxygen concentration on radiosensitivity that cannot be described in terms of the Howard-Flanders/Alper model. (2) The oxygen effect in relation to survival level. The influence of very low oxygen concentrations on the shoulder of the survival curves of irradiated cells is still controversial. Also, the oxygen dependence of repair processes for sublethal and potentially lethal damage need to be better defined. (3) Time-scale of the oxygen effect. All the experimental data obtained with the use of fast techniques indicate that the time scale of the oxygen effect is consistent with that of free radical reactions. This appears to be compatible with the hypothesis that oxygen acts by fixation of a radiation-induced reversible damage. The existence of two types of damage with different rates of decay is suggested, both in bacterial and mammalian cells. (4) Molecular mechanisms of the oxygen effect. In spite of the very large literature on this subject, the identification of the detailed molecular mechanisms of the oxygen effect must still be considered goals for future research

  15. Age and radiation sensitivity of rat mammary clonogenic cells

    International Nuclear Information System (INIS)

    Shimada, Yoshiya; Yasukawa-Barnes, J.; Kim, R.Y.; Gould, M.N.; Clifton, K.H.

    1994-01-01

    The relative risk of breast cancer is very high among women who were exposed to ionizing radiation during or before puberty. In the current studies, the surviving fractions of clonogenic mammary cells of groups of virgin rats were estimated after single exposures to 137 Cs γ rays at intervals from 1 to 12 weeks after birth. The radiosensitivity of clonogens from prepubertal rats was high and changed with the onset of puberty at between 4 and 6 weeks of age. By this time, the increase in the size of the clonogenic cell subpopulation was slowing and differentiation of terminal mammary end buds and alveolar structures was occurring. Analysis of the relationship of clonogen survival and radiation dose according to the α/β model showed that the exponential αD term predominated at the second and fourth weeks of age. By the eighth week of age, the βD 2 term had come to predominate and the survival curve had a pronounced initial convex shoulder. Further experiments are required to determine whether there is an association between the high sensitivity of the prepubertal and pubertal mammary clonogens to radiation killing and a high susceptibility to radiogenic initiation of cancer. 24 refs., 4 figs., 1 tab

  16. Roadmap to Clinical Use of Gold Nanoparticles for Radiation Sensitization

    Energy Technology Data Exchange (ETDEWEB)

    Schuemann, Jan, E-mail: jschuemann@mgh.harvard.edu [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Berbeco, Ross [Department of Radiation Oncology, Brigham and Women' s Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts (United States); Chithrani, Devika B. [Department of Physics, Ryerson University, Toronto, Ontario (Canada); Cho, Sang Hyun [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Kumar, Rajiv [Nanomedicine Science and Technology Center, Northeastern University, Boston, Massachusetts (United States); Department of Radiation Oncology, Harvard Medical School, Boston, Massachusetts (United States); McMahon, Stephen J. [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Centre for Cancer Research and Cell Biology, Queen' s University Belfast, Belfast, Northern Ireland (United Kingdom); Sridhar, Srinivas [Nanomedicine Science and Technology Center, Northeastern University, Boston, Massachusetts (United States); Department of Radiation Oncology, Harvard Medical School, Boston, Massachusetts (United States); Krishnan, Sunil [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2016-01-01

    The past decade has seen a dramatic increase in interest in the use of gold nanoparticles (GNPs) as radiation sensitizers for radiation therapy. This interest was initially driven by their strong absorption of ionizing radiation and the resulting ability to increase dose deposited within target volumes even at relatively low concentrations. These early observations are supported by extensive experimental validation, showing GNPs' efficacy at sensitizing tumors in both in vitro and in vivo systems to a range of types of ionizing radiation, including kilovoltage and megavoltage X rays as well as charged particles. Despite this experimental validation, there has been limited translation of GNP-mediated radiation sensitization to a clinical setting. One of the key challenges in this area is the wide range of experimental systems that have been investigated, spanning a range of particle sizes, shapes, and preparations. As a result, mechanisms of uptake and radiation sensitization have remained difficult to clearly identify. This has proven a significant impediment to the identification of optimal GNP formulations which strike a balance among their radiation sensitizing properties, their specificity to the tumors, their biocompatibility, and their imageability in vivo. This white paper reviews the current state of knowledge in each of the areas concerning the use of GNPs as radiosensitizers, and outlines the steps which will be required to advance GNP-enhanced radiation therapy from their current pre-clinical setting to clinical trials and eventual routine usage.

  17. Radiation sensitivity of B-16 melanoma

    International Nuclear Information System (INIS)

    Griem, M.L.; Malkinson, F.D.; Kalis, J.B.; Shefner, A.

    1984-01-01

    A model has been developed for radiation studies of melanoma. Β-16 melanoma (NCI), carried by subcutaneous implant in C57BL/6NCr mice was implanted instramuscularly into the right rear leg of female B6C3F1 mice. Test mice were inoculated with 1 x 10/sup 5/, 5 x 10/sup 5/, and 1 x 10/sup 6/ tumor cells to determine an appropriate tumor challenge for a reproducible and suitable median survival time. A challenge inoculum of 5 x 10/sup 5/ tumor cells was subsequently chosen as the standard tumor dose for test animals used in subsequent radiation dose response studies. Tumor-bearing test animals were treated with 500, 1000, 1500, or 2000 rads of 250 kV x-rays either 4 days or 14 days after tumor implantation. Only the tumorbearing leg of the test mouse was exposed during irradiation; the animal was otherwise protected by lead shielding. The median survival time of tumorbearing unirradiated mice was 24.4 days. Radiation on day 4 postinoculation was more effective than radiation administered on day 14. Median survival time for the 4 radiation dose groups given x-rays on day 4 were 31.0, 38.2, 59.0, and 60.0 days with progressive increases in radiation dose. Median survival times for mice irradiated on day 14 were 26.8, 31.8, 34.8, and 49.2 days as the radiation doses increased. This mouse melanoma model can be used in combined modality studies

  18. Physiological and genetics studies of highly radiation-resistant bacteria

    International Nuclear Information System (INIS)

    Keller, L.C.

    1981-01-01

    The phenomenon of radiation resistance was studied using micrococci and Moraxella-Acinetobacter capable of surviving very high doses of gamma radiation which were isolated from foods. Physiological age, or growth phase, was found to be an important factor in making comparisons of radiation-resistance among different bacteria and their mutants. Radiation-resistant bacteria were highly resistant to the lethal effect of nitrosoguanidine used for mutagenesis. Studies of relative resistance of radiation-resistant bacteria, radiation-sensitive mutants, and nonradiation-resistant bacteria to killing by different chemical mutagens did not reveal a correlation between the traits of radiation resistance and mutagen resistance among different strains. Comparisons of plasmid profiles of radiation-resistant bacteria and selected radiation-sensitive mutants suggested the possibility that plasmids may carry genes involved in radiation resistance

  19. Superoxide dismutase amplifies organismal sensitivity to ionizing radiation

    International Nuclear Information System (INIS)

    Scott, M.D.; Meshnick, S.R.; Eaton, J.W.

    1989-01-01

    Although increased superoxide dismutase (SOD) activity is often associated with enhanced resistance of cells and organisms to oxidant challenges, few direct tests of the antioxidant importance of this enzyme have been carried out. To assess the importance of SOD in defending against gamma-radiation, we employed Escherichia coli with deficient, normal, and super-normal enzyme activities. Surprisingly, the radiation sensitivity of E. coli actually increases as bacterial SOD activity increases. Elevated intracellular SOD activity sensitizes E. coli to radiation-induced mortality, whereas SOD-deficient bacteria show normal or decreased radiosensitivity. Toxic effects of activated oxygen species are involved in this phenomenon; bacterial SOD activity has no effect on radiation sensitivity under anaerobic conditions or on the lethality of other, non-oxygen-dependent, toxins such as ultraviolet radiation

  20. Sensitiveness of jasmine cuttings to gamma radiation

    International Nuclear Information System (INIS)

    Devaiah, K.A.; Srivastava, H.C.

    1989-01-01

    Half lethal dose (LD 50 ) gamma radiation for five genotypes of jasmine and the effect of such radiation on their rooting parameters were studied. The LD 50 was close to 2.5 krad for Jasminum grandiflorum var. Pink Pin, 0.5 krad for var. Pink Thrum, 2.5 krad for J. flexile Valh., 1 krad for J. calophyllum Wall and 2 krad for J. sambac Ait var. 'Gundumalli'. Percentage of rooting, number of roots per cutting, length and thickness of roots decreased with increase in intensity of gamma irradiation. (author) 8 refs.; 4 tabs

  1. Radiation sensitivity of human lung cancer cell lines

    International Nuclear Information System (INIS)

    Carmichael, J.; Degraff, W.G.; Gamson, J.; Russo, G.; Mitchell, J.B.; Gazdar, A.F.; Minna, J.D.; Levitt, M.L.

    1989-01-01

    X-Ray survival curves were determined using a panel of 17 human lung cancer cell lines, with emphasis on non-small cell lung cancer (NSCLC). In contrast to classic small cell lung cancer (SCLC) cell lines, NSCLC cell lines were generally less sensitive to radiation as evidenced by higher radiation survival curve extrapolation numbers, surviving fraction values following a 2Gy dose (SF2) and the mean inactivation dose values (D) values. The spectrum of in vitro radiation responses observed was similar to that expected in clinical practice, although mesothelioma was unexpectedly sensitive in vitro. Differences in radiosensitivity were best distinguished by comparison of SF2 values. Some NSCLC lines were relatively sensitive, and in view of this demonstrable variability in radiation sensitivity, the SF2 value may be useful for in vitro predictive assay testing of clinical specimens. (author)

  2. The Visualization of Infrared Radiation Using Thermal Sensitive Foils

    Science.gov (United States)

    Bochnícek, Zdenek

    2013-01-01

    This paper describes a set of demonstration school experiments where infrared radiation is detected using thermal sensitive foils. The possibility of using standard glass lenses for infrared imaging is discussed in detail. It is shown that with optic components made from glass, infrared radiation up to 2.5 µm of wavelength can be detected. The…

  3. Toward the elucidation of factors concerning the individual difference of radiation sensitivity, and the reduction of radiation risks

    International Nuclear Information System (INIS)

    Nenoi, Mitsuru; Nakajima, Tetsuo; Wang, Bing

    2013-01-01

    This article describes studies aiming at the title subject and contains 2 topics of genetic and non-genetic factors modifying the radiation sensitivity. The ultimate purposes of those studies are the introduction of individual weighting factor to correct the individual differences of the sensitivity (IDS) and the practical control of the sensitivity-concerned factors, in the field of medical exposure. For genetic factors, described are studies on factors modifying the sensitivity at DNA repair and on the control of the sensitivity through the DNA repairing factors. The former, using cultured cells, aims at identifying protein (gene) of possible biomarker for IDS in non-homologous end-joining (NHEJ), an important mechanism in repairing the double strand break of DNA. Ku protein is found as the candidate. The latter has revealed that cells lacking Artemis, XRCC4 or MDC1 gene are highly sensitive, and are planning to suppress Artemis activity artificially, which may lead to the reduction of radiation cancer formation due to the death of highly sensitive cells. For non-genetic factors, described are studies on the life habits modifying the sensitivity, on the control of the sensitivity through the radiation-induced adaptive response and with steroid hormone. In the first, in mice treated with high-calorie diet and X-irradiation, a possible radiation response is suggested in the hepatic DNA-methylation and micro-RNA. Second, the combination of radiation adaptive response in the genome damage and restriction of diet ingestion is shown to lower the sensitivity of mice with use of C, Ne ion or X-ray irradiation. Third, in studies on the radiation-induced formation and condensation of breast cancer stem cells in the presence of progesterone, the hormone is found to produce micro-RNA molecules relating with the suppression of cellular senescence and repressed carcinogenesis with over-expression of apoptosis inhibitory molecules. (T.T.)

  4. Sensitivity of oysters (Crassostrea Brasiliana) to radiation

    International Nuclear Information System (INIS)

    Mattiolo Marchese, S.R.; Mastro, N.L. del

    1997-01-01

    Various foods including oysters, crabs and shrimps have been shown to be possible transmitters of Vibrio ssp. Irradiation of sea-foods is being considered an alternative to intervention measures in Public Health against food borne diseases. The aim of this work was to establish, the radiation resistance of the oysters Crassostrea brasiliana. The oysters were irradiated with Co-60 radiation with doses of 0, 1.5, 3 and 6 kGy. Survival curves as a function of time showed that 100% of the oysters irradiated with doses of 3 kGy survived at least 6 days. 100% those irradiated with 6 kGy survived 3 days. The obtained results are auspicious considering that a dose of 2 kGy is already effective in the diminishing of the microbial load on oysters. (author)

  5. Individual Dosimetry for High Energy Radiation Fields

    International Nuclear Information System (INIS)

    Spurny, F.

    1999-01-01

    The exposure of individuals on board aircraft increased interest in individual dosimetry in high energy radiation fields. These fields, both in the case of cosmic rays as primary radiation and at high energy particle accelerators are complex, with a large diversity of particle types, their energies, and linear energy transfer (LET). Several already existing individual dosemeters have been tested in such fields. For the component with high LET (mostly neutrons) etched track detectors were tested with and without fissile radiators, nuclear emulsions, bubble detectors for both types available and an albedo dosemeter. Individual dosimetry for the low LET component has been performed with thermoluminescent detectors (TLDs), photographic film dosemeters and two types of electronic individual dosemeters. It was found that individual dosimetry for the low LET component was satisfactory with the dosemeters tested. As far as the high LET component is concerned, there are problems with both the sensitivity and the energy response. (author)

  6. Relative radiation sensitivity of insulators, stabilizers, and superconductors

    International Nuclear Information System (INIS)

    Van Konynenburg, R.A.; Guinan, M.W.

    1980-12-01

    The operating conditions of the magnets including temperature and radiation fields are discussed. Comments were made on the nuclear heating. Components of the magnet system, including the materials used, the important properties, the atomic structure, the damage mechanism, and the effects of room temperature warmup are described. Some failure criteria for the various components are suggested. Available data concerning radiation effects on each component are discussed. Their radiation sensitivities are compared using the conditions calculated for the ETF toroidal field magnet inboard leg, and ranked in order of sensitivity. Comments were made on the implications of this ranking for the directions of future applied materials research

  7. Effect of troglitazone on radiation sensitivity in cervix cancer cells

    International Nuclear Information System (INIS)

    An, Zheng Zhe; Liu, Xian Guang; Song, Hye Jin; Choi, Chi Hwan; Kim, Won Dong; Park, Woo Yoon; Yu, Jae Ran

    2012-01-01

    Troglitazone (TRO) is a peroxisome proliferator-activated receptor γ (PPARγ ) agonist. TRO has antiproliferative activity on many kinds of cancer cells via G1 arrest. TRO also increases Cu 2+ /Zn 2+ -superoxide dismutase (CuZnSOD) and catalase. Cell cycle, and SOD and catalase may affect on radiation sensitivity. We investigated the effect of TRO on radiation sensitivity in cancer cells in vitro. Three human cervix cancer cell lines (HeLa, Me180, and SiHa) were used. The protein expressions of SOD and catalase, and catalase activities were measured at 2-10 μM of TRO for 24 hours. Cell cycle was evaluated with flow cytometry. Reactive oxygen species (ROS) was measured using 2',7'-dichlorofluorescin diacetate. Cell survival by radiation was measured with clonogenic assay. By 5 μM TRO for 24 hours, the mRNA, protein expression and activity of catalase were increased in all three cell lines. G0- G1 phase cells were increased in HeLa and Me180 by 5 μM TRO for 24 hours, but those were not increased in SiHa. By pretreatment with 5 μM TRO radiation sensitivity was increased in HeLa and Me180, but it was decreased in SiHa. In Me180, with 2 μM TRO which increased catalase but not increased G0-G1 cells, radiosensitization was not observed. ROS produced by radiation was decreased with TRO. TRO increases radiation sensitivity through G0-G1 arrest or decreases radiation sensitivity through catalasemediated ROS scavenging according to TRO dose or cell types. The change of radiation sensitivity by combined with TRO is not dependent on the PPAR γ expression level.

  8. Guide for use of radiation-sensitive indicators. 2. ed.

    International Nuclear Information System (INIS)

    2002-01-01

    This guide covers the use of radiation-sensitive indicators in radiation processing. These indicators may be labels, papers, inks or packaging materials which undergo a color change or become colored when exposed to ionizing radiation. The purpose of these indicators is to determine visually whether or not a product has been irradiated, rather than to measure different dose levels. Such materials are not dosimeters and should not be used as a substitute for proper dosimetry. Information about dosimetry systems for ionizing radiation is provided in other ASTM and ISO/ASTM documents (see ISO/ASTM Guide 51261

  9. High-let radiation carcinogenesis

    International Nuclear Information System (INIS)

    Fry, R.J.M.; Powers-Risius, P.; Alpen, E.L.; Ainsworth, E.J.; Ullrich, R.L.

    1982-01-01

    Recent results for neutron radiation-induced tumors are presented to illustrate the complexities of the dose-response curves for high-LET radiation. It is suggested that in order to derive an appropriate model for dose-response curves for the induction of tumors by high-LET radiation it is necessary to take into account dose distribution, cell killing and the susceptibility of the tissue under study. Preliminary results for the induction of Harderian gland tumors in mice exposed to various heavy ion beams are presented. The results suggest that the effectiveness of the heavy ion beams increases with increasing LET. The slopes of the dose-response curves for the different high-LET radiations decrease between 20 and 40 rads and therefore comparisons of the relative effectiveness should be made from data obtained at doses below about 20 to 30 rads

  10. Multiparametric assessment of radiation effects for the individual radiation sensitivity estimation

    International Nuclear Information System (INIS)

    2006-01-01

    The effects of low dose irradiation are highly relevant for radiation protection in the public. The sensitivity to clastogenic and tumorigenic effects of ionizing radiation (IR) varies considerably amongst individuals. Examples for genetically determined enhanced sensitivity are well known in some hereditary diseases: patients with chromosomal instability syndromes, Ataxia telangiectasia (A-T), Nijmegen Breakage Syndrome (NBS) and Bloom Syndrome (BS) show strongly enhanced sensitivity towards IR, severe immunodeficiencies, and a high incidence for developing leukemias and lymphomas. This obvious coincidence of enhanced radiosensitivity and tumor risk, and the frequently observed enhanced radiosensitivity of genetically non-defined tumor patients indicate that tumor patients may constitute a subpopulation with enriched genetical predisposition for enhanced radiosensitivity. Furthermore, a subpopulation of radiosensitive individuals may be part of the probably inconspicuous total population. For example, individuals heterozygous for the above mentioned genes (and possibly some other genes) show enhanced radiosensitivity if compared with the normal population. In general, heterozygous carriers of those hereditary deficiencies are clinically inconspicuous, but due an haploinsufficiency their tumour risk may be enhanced. This has been shown for mice carrying an heterozygous Nbs1 mutation (J.-Q. Wang, Lyon, pers. Communication). Our findings concerning enhanced radiation-induced chromosomal aberrations in heterozygous Nbs1 cell lines support this notion. The identification of high risk groups with enhanced radiosensitivity is therefore an important task for radioprotection. This project aimed at establishing a procedure which allows to test various cellular parameters as indicators for effects of radiation. A standard protocol for the isolation and cryoconservation of primary blood cells was developed. DNA repair analysis (Comet Assay) and radiation-induced apoptosis

  11. Effect of particle size in the TL response of natural quartz sensitized by high dose of gamma radiation and heat-treatments

    Directory of Open Access Journals (Sweden)

    Álvaro Barbosa de Carvalho Jr

    2010-06-01

    Full Text Available This work investigates the effect of particle size in the thermoluminescence (TL response of a quartz crystal that was initially crushed and classified into ten size fractions between 38 μm and 5 mm. Aliquots of each size fraction were sensitized with a dose of 25 kGy of γ rays and heat-treatments at 400 °C. TL glow curves of sensitized and non-sensitized samples were recorded as a function of different test-doses of γ rays. For the non-sensitized samples, the TL peak near 325 °C increases with the decrease in particle size. In the case of sensitized samples, a strong TL peak near 300 °C increases with the increase in particle size up to mean grain size equal to 304 μm. Above 304 μm, an abrupt reduction in the TL intensity is noticed for the sensitized peak. These effects are discussed in relation to the specific surface area of quartz particles and the intensity of the electron paramagnetic resonance signal of the E'1 center induced by the sensitization process.

  12. Micronuclei: sensitivity for the detection of radiation induced damage

    International Nuclear Information System (INIS)

    Di Giorgio, M.; Nasazzi, N.B.; Taja, M.R.

    1998-01-01

    The in vitro cytokinesis-block (CB) micronucleus (MN) assay for human peripheral blood has been used extensively for the assessment of chromosomal damage induced by ionizing radiation and chemicals and considered a suitable biological dosimeter for estimating in vivo whole body exposures, particularly in the case of large scale radiation accidents. One of the major drawbacks of the MN assay is its reduced sensitivity for the detection of damage induced by low doses of low LET radiation, due to the high variability among the spontaneous MN frequencies. It is suggested that age, smoking habit and sex are the main confounding factors that contribute to the observed variability. Previous work in our laboratory, shows a significant positive correlation of the spontaneous and radiation induced MN frequencies with age and smoking habit, the latter being the strongest confounder. These findings led to in vitro studies of the dose-response relationships for smoking and non smoking donors evaluated separately, using 60 Co γ rays. The objectives of the present work are: 1-To increase the amount of data of the dose-response relationships, using γ rays from a 60 Co source, for smoking and non smoking donors, in order to find, if applicable, a correction factor for the calibration curve that takes into account the smoking habit of the individual in the case of accidental overexposure dose assessment, particularly in the low dose range. 2-To establish general conclusions on the current state of the technique. The sample for smoking and non smoking calibration curves was enlarged in the range of 0Gy to 2Gy. The fitting of both curves, performed up to the 2Gy dose, resulted in a linear quadratic model. MN distribution among bi nucleated cells was found to be over dispersed with respect to Poisson distribution, the average ratio of variance to mean being 1.13 for non smokers and 1.17 for smokers. Each fitted calibration curve, for smoking and non smoking donors, fell within the 95

  13. Radiation sensitization studies by silymarin on HCT-15 cells

    International Nuclear Information System (INIS)

    Lal, Mitu; Gupta, Damodar; Arora, R.

    2014-01-01

    Radiotherapy has been widely used for treatment of human cancers. However, cancer cells develop radioresistant phenotypes following multiple exposures to the treatment agent that decrease the efficacy of radiotherapy. Here it was investigated that the radiation sensitization effects of silymarin found in colon cancer. The aim of this study was to investigate mechanisms involved in radiation sensitization growth inhibitory effect of silymarin in combination with radiation, in Human colon carcinoma (HCT-15). The human colon carcinoma was utilized and SRB-assay was performed to study anti-proliferative effect of silymarin in combination with gamma radiation (2 Gy) appropriate radiation dose was optimized and confirmed by clonogenic assay. Microscopic analysis was done by staining with Hoechst-33342, DAPI, Propidium iodide to confirm the presence of apoptosis. Nitric oxide production, changes in lipid peroxidation, Cell cycle analysis were carried out and mitochondrial membrane potential was measured by uptake of cationic dye JC-1 by using flow cytometer. Silymarin in combination with radiation (2 Gy) inhibited 70% ± 5% population growth of HCT-15 cells in time and dose dependent manner. Pre treatment of cells with silymarin for 30 min before radiation was found to be most effective for radiation sensitization. There was 25% increase in levels of nitric oxide as compare to control, whereas 2.5 fold change in lipid peroxidation with respect to control. IR-induced apoptosis in HCT-15 cell line was significantly enhanced by silymarin, as reflected by viability, DNA fragmentation, and mitochondrial dysfunction. Additionally, silymarin in combination with IR is found to be effective in sensitization of HCT-15 cells. In vivo studies on development of tumor and sensitization aspects needs to done in future. (author)

  14. Radiation sensitive devices and systems for detection of radioactive materials and related methods

    Science.gov (United States)

    Kotter, Dale K

    2014-12-02

    Radiation sensitive devices include a substrate comprising a radiation sensitive material and a plurality of resonance elements coupled to the substrate. Each resonance element is configured to resonate responsive to non-ionizing incident radiation. Systems for detecting radiation from a special nuclear material include a radiation sensitive device and a sensor located remotely from the radiation sensitive device and configured to measure an output signal from the radiation sensitive device. In such systems, the radiation sensitive device includes a radiation sensitive material and a plurality of resonance elements positioned on the radiation sensitive material. Methods for detecting a presence of a special nuclear material include positioning a radiation sensitive device in a location where special nuclear materials are to be detected and remotely interrogating the radiation sensitive device with a sensor.

  15. γ-radiation induces cellular sensitivity and aberrant methylation in human tumor cell lines.

    Science.gov (United States)

    Kumar, Ashok; Rai, Padmalatha S; Upadhya, Raghavendra; Vishwanatha; Prasada, K Shama; Rao, B S Satish; Satyamoorthy, Kapettu

    2011-11-01

    Ionizing radiation induces cellular damage through both direct and indirect mechanisms, which may include effects from epigenetic changes. The purpose of this study was to determine the effect of ionizing radiation on DNA methylation patterns that may be associated with altered gene expression. Sixteen human tumor cell lines originating from various cancers were initially tested for radiation sensitivity by irradiating them with γ-radiation in vitro and subsequently, radiation sensitive and resistant cell lines were treated with different doses of a demethylating agent, 5-Aza-2'-Deoxycytidine (5-aza-dC) and a chromatin modifier, Trichostatin-A (TSA). Survival of these cell lines was measured using 3-(4, 5-Dimethylthiazol- 2-yl)-2, 5-diphenyltetrazolium (MTT) and clonogenic assays. The effect of radiation on global DNA methylation was measured using reverse phase high performance liquid chromatography (RP-HPLC). The transcription response of methylated gene promoters, from cyclin-dependent kinase inhibitor 2A (p16(INK4a)) and ataxia telangiectasia mutated (ATM) genes, to radiation was measured using a luciferase reporter assay. γ-radiation resistant (SiHa and MDAMB453) and sensitive (SaOS2 and WM115) tumor cell lines were examined for the relationship between radiation sensitivity and DNA methylation. Treatment of cells with 5-aza-dC and TSA prior to irradiation enhanced DNA strand breaks, G2/M phase arrest, apoptosis and cell death. Exposure to γ-radiation led to global demethylation in a time-dependent manner in tumor cells in relation to resistance and sensitivity to radiation with concomitant activation of p16(INK4a) and ATM gene promoters. These results provide important information on alterations in DNA methylation as one of the determinants of radiation effects, which may be associated with altered gene expression. Our results may help in delineating the mechanisms of radiation resistance in tumor cells, which can influence diagnosis, prognosis and

  16. Evaluation of texaphyrins as tumor selective radiation sensitizers

    International Nuclear Information System (INIS)

    Qing Fan; Woodburn, Kathryn W.; Young, Stuart W.

    1997-01-01

    Texaphyrins are expanded porphyrin macrocycles that selectively localize and are retained in cancerous lesions. The function of the texaphyrin can be manipulated by the incorporation of different metal ions into the macrocycle's central cavity. Gadolinium texaphyrin (Gd-Tex) and lutetium texaphyrin (Lu-Tex) were evaluated as radiation sensitizers. Radiation sensitization studies were performed using SMT-F and EMT6 mammary tumor-bearing mice. Single and multifraction dose regimens were performed. SMT-F bearing DBA/2N mice and EMT6 bearing Balb/c mice were intravenously administered with Gd-Tex of Lu-Tex (5-40 μmol/kg) 30 minutes to 5 hours prior to radiation (10-50 Gray) for the single fraction studies. The more radioresistant EMT-6 sarcoma model was used for the multifraction studies. The tumor bearing animals were injected with Gd-Tex (5, 20, or 40 μmol/kg) to 2 hours prior radiation (1, 2, or 4 Gray), this regimen was performed for five consecutive days. Gd-Tex is paramagnetic and has a strong fluorescence signal. Tumor selectivity was determined by MRI and fluorescence spectral imaging before and up to 24 hours following the administration of Gd-Tex. Gd-Tex but not Lu-Tex, proved to be an effective radiation sensitizer. Administration of Gd-Tex (40 μmol/kg) prior to a single dose of 30 Gray radiation provided a significant improvement in survival in SMT-F-bearing DBA/2N mice as compared to animals receiving radiation alone (p = 0.0034). A significant radiation sensitization effect was also found in multiple fraction studies (five consecutive days) with Balb/C mice bearing EMT-6 neoplasma-- following 1 Gray of radiation for 5 days there was a significant difference between the 20 and 40 μmol/kg group and controls (p = 0.003, p = 0.005 respectively). MRI and fluorescence spectral imaging studies of tumor bearing animals revealed excellent contrast enhancement of the tumor which persisted up to 24 hours. Texaphyrins localize in neoplasms as visualized using MRI

  17. DNA repair and radiation sensitivity in mammalian cells

    International Nuclear Information System (INIS)

    Chen, D.J.C.; Stackhouse, M.; Chen, D.S.

    1993-01-01

    Ionizing radiation induces various types of damage in mammalian cells including DNA single-strand breaks, DNA double-strand breaks (DSB), DNA-protein cross links, and altered DNA bases. Although human cells can repair many of these lesions there is little detailed knowledge of the nature of the genes and the encoded enzymes that control these repair processes. We report here on the cellular and genetic analyses of DNA double-strand break repair deficient mammalian cells. It has been well established that the DNA double-strand break is one of the major lesions induced by ionizing radiation. Utilizing rodent repair-deficient mutant, we have shown that the genes responsible for DNA double-strand break repair are also responsible for the cellular expression of radiation sensitivity. The molecular genetic analysis of DSB repair in rodent/human hybrid cells indicate that at least 6 different genes in mammalian cells are responsible for the repair of radiation-induced DNA double-strand breaks. Mapping and the prospect of cloning of human radiation repair genes are reviewed. Understanding the molecular and genetic basis of radiation sensitivity and DNA repair in man will provide a rational foundation to predict the individual risk associated with radiation exposure and to prevent radiation-induced genetic damage in the human population

  18. Radiation vulcanization of natural rubber latex sensitized with commercial gases

    Energy Technology Data Exchange (ETDEWEB)

    Chirinos, H.; Lugao, A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    2002-07-01

    The industrial activities using natural rubber latex are fully compatible with rural areas in Amazon and other places in Brazil, as well as in other tropical countries. However the classical sulfur vulcanization presents many occupational problems for the workers in rural areas. Radiation vulcanization of natural rubber latex is a much more friendly process as sulfur compounds are not needed for crosslinking, although chemicals as acrylate monomers, particularly multifunctional acrylates are still used as sensitizers for radiation processes. Two commercial gases, acetylene and butadiene, were selected as sensitizers for the radiation vulcanization of natural rubber latex instead of acrylates. These gases accelerate the crosslinking rates of the cure process and lower the radiation dose required to achieve vulcanization of natural rubber latex and improve the mechanical properties to reduce the tackiness of rubber goods. (author)

  19. Radiation vulcanization of natural rubber latex sensitized with commercial gases

    International Nuclear Information System (INIS)

    Chirinos, H.; Lugao, A.

    2002-01-01

    The industrial activities using natural rubber latex are fully compatible with rural areas in Amazon and other places in Brazil, as well as in other tropical countries. However the classical sulfur vulcanization presents many occupational problems for the workers in rural areas. Radiation vulcanization of natural rubber latex is a much more friendly process as sulfur compounds are not needed for crosslinking, although chemicals as acrylate monomers, particularly multifunctional acrylates are still used as sensitizers for radiation processes. Two commercial gases, acetylene and butadiene, were selected as sensitizers for the radiation vulcanization of natural rubber latex instead of acrylates. These gases accelerate the crosslinking rates of the cure process and lower the radiation dose required to achieve vulcanization of natural rubber latex and improve the mechanical properties to reduce the tackiness of rubber goods. (author)

  20. Radiation sensitivity of food decay fungi

    International Nuclear Information System (INIS)

    Chang, H.G.; Lee, B.H.

    1980-01-01

    Five species of food decay fungi, Aspergillus flavus, Asp. uiger, Penicillium sp., Botrytis cinerea and Rhizopus stolonifer, were examined for their radiosensitivity in several suspension media. Asp. flavus, Asp. niger and Penicillium sp. have almost the same sensitivity toward gamma rays, with D value in the range of 30 to 35 K rad, whereas Botrytis cinerea has a D value of approximately 55 K rad and Rhizopus stolonifer, the most resistant fungus studied, has a D value of approximately 100 K rad. Dry spores of Asp. flavus showed a considerable increase in their radioresistance when compared with spores irradiated in water. Asp. flavus and Penicillium sp. spores irradiated in citrate buffer at pH 3-7 showed almost no change in their radiosensitivity with pH, but Botrytis cinerea spores showed a distinct decrease in their radioresistance at pH 6 and 7. Penicillium sp. spores irradiated in sucrose solutions showed no significant change in their radioresistance. Botrytis cinerea spores displayed a higher radioresistance when they were irradiated in sucrose solution than in water. (author)

  1. Genetics of human sensitivity to ultraviolet radiation

    Science.gov (United States)

    Cleaver, James E.

    1994-07-01

    the major human health effects of solar and artificial UV light occur from the UVB and UVC wavelength ranges and involve a variety of short-term and long-term deleterious changes to the skin and eyes. the more important initial damage to cellular macromolecules involves dimerization of adjacent pyrimidines in DNA to produce cyclobutane pyrimidine dimes, (6-4) pyrimidine- pyrimidone, and (6-4) dewar photoproducts. these photoproducts can be repaired by a genetically regulated enzyme system (nucleotide excision repair) which removes oligonucleotides 29-30 nucleotides long that contain the photoproducts, and synthesizes replacement patches. At least a dozen gene products are involved in the process of recognizing photoproducts in DNA, altering local DNA helicity and cleaving the polynucleotide chain at defined positions either side of a photoproduct. Hereditary mutations in many of these genes are recognized in the human genetic disorders xeroderma pigmentosum (XP), Cockayne syndrome (CS), and trichothiodystrophy (TTD). Several of the gene products have other functions involving the regulation of gene transcription which accounts for the complex clinical presentation of repair deficient diseases that involve sensitivity of the skin and eyes to UV light, increased solar carcinogenesis (in XP), demyelination, and ganglial calcification (in CS), hair abnormalities (in TTD), and developmental and neurological abnormalities

  2. Relationship between intrinsic radiation sensitivity and metastatic potential

    International Nuclear Information System (INIS)

    Lewis, Anne M.; Mei, Su; Doty, Jay; Chen Yi; Pardo, Francisco S.

    1996-01-01

    Purpose: Prior studies emphasized genetic modulation of tumorigenicity, and experimental metastatic potential in cells transfected with oncogenes. Whether the intrinsic radiation sensitivity of cells might correlate with parallel changes in metastatic potential is unknown. Methods and Materials: Rat embryo cells (REC) were transfected with the following oncogenes, and where appropriate, with corresponding selection markers: pCMV neopEJ6.6ras, pEJ6.6ras/v-myc, pE1a, and pEJ6-.6ras/E1a. Individual transfectant clones and corresponding pooled cellular populations were propagated in selective medium. In vitro cellular radiation sensitivity was determined via clonogenic assays, a minimum of three, by standard techniques and individual SF 2 and MID parameters determined. Tumorigenicity was defined as the number of tumors forming following the injection of 1 x 10 5 - 1 x 10 6 cells into the axillary pouch of three different strains of immune-deficient mice. Animals were killed once resultant tumors reached a maximum size of 1.5-2.0 cm in maximum diameter. For determination of experimental metastatic potential, between 1 x 10 5 -1 x 10 6 cells were injected into the tail veins of litter-matched sibling mice in parallel to the tumorigenicity studies. Results: Radiobiologic studies indicate similar levels of radiation sensitivity among REC, mock-transfected REC, E1a, and combined E1a/ras transfectants. pEJ6.6ras, and combined ras/myc transfected pooled cellular populations demonstrated increases in radiation resistance when compared to the pooled radiobiologic data from untransfected and mock-transfected corresponding pooled cellular populations (p 2 , MID). Rat embryo cells, E1a, and mock-transfectants were relatively radiation sensitive and nontumorigenic. pE1a/ras was tumorigenic but demonstrated relatively low experimental metastatic potential. Ras, and ras/myc transfectants, demonstrated similar levels of experimental metastatic potential on lung colonization assays

  3. Incidence of radiation-induced Graves' disease in patients treated with radioiodine for thyroid autonomy before and after introduction of a high-sensitivity TSH receptor antibody assay

    Energy Technology Data Exchange (ETDEWEB)

    Dunkelmann, Simone; Wolf, Ricarda; Koch, Annedore; Kittner, Christian; Groth, Peter; Schuemichen, Carl [University of Rostock, Clinic of Nuclear Medicine, Rostock (Germany)

    2004-10-01

    Autoimmune hyperthyroidism may occur several months after radioiodine therapy (RIT) for functional thyroid autonomy. Exacerbation of pre-existing subclinical Graves' disease (GD) has been held responsible for this phenomenon. Determination of TSH receptor antibody using solubilised porcine epithelial cell membranes is insensitive and may have failed to diagnose GD in these patients before RIT. Following the introduction of a more sensitive assay, using the human TSH receptor as an antigen, it has been expected that the incidence of radiation-induced GD after RIT for functional thyroid autonomy will be reduced. In a first group of 1,428 patients treated between November 1993 and March 1997 (group I) we used the porcine TRAb assay to exclude GD, while in a second group comprising 1,408 patients treated between January 2000 and December 2001 (group II), GD was excluded using the human TRAb assay. A matched control group of 231 patients was derived from group II. In group I a total of 15 (1.05%) patients developed obvious or suspected radiation-induced GD, while in group II 17 (1.2%) did so; the interval until development of GD was 8.4 and 8.8 months, respectively, after RIT. Serum anti-thyroid peroxidase levels before RIT were elevated in 36.4% of group I patients and 47.1% of group II patients, but in only 5.6% of the control group. Other non-specific signs of mild immunopathy of the thyroid were seen retrospectively in 73.3%, 64.7% and 16.0% of the patients in these three groups, respectively. In conclusion, the introduction of a high-sensitivity TRAb assay did not reduce the incidence of autoimmune hyperthyroidism occurring late after RIT for functional thyroid autonomy, but mild immunopathy of the thyroid is seen more frequently in these patients and seems to be a predisposing factor in the development of radiation-induced GD. (orig.)

  4. Development of a high sensitivity monitor for radionuclides characterization. Final report, August 1995--April 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-06-01

    This report describes the development of a high sensitivity monitor for radiation, and the feasibility of applying a new radiation imaging concept developed for medical research to soil contamination. The concept utilizes sensors with storage photostimulable phosphor technology as radiation detectors. They are applicable to all types of radiation including tritium.

  5. Development of a high sensitivity monitor for radionuclides characterization. Final report, August 1995--April 1996

    International Nuclear Information System (INIS)

    1996-06-01

    This report describes the development of a high sensitivity monitor for radiation, and the feasibility of applying a new radiation imaging concept developed for medical research to soil contamination. The concept utilizes sensors with storage photostimulable phosphor technology as radiation detectors. They are applicable to all types of radiation including tritium

  6. Delay-Line Three-Dimensional Position Sensitive Radiation Detection

    Science.gov (United States)

    Jeong, Manhee

    High-resistivity silicon(Si) in large volumes and with good charge carrier transport properties has been produced and achieved success as a radiation detector material over the past few years due to its relatively low cost as well as the availability of well-established processing technologies. One application of that technology is in the fabrication of various position-sensing topologies from which the incident radiation's direction can be determined. We have succeeded in developing the modeling tools for investigating different position-sensing schemes and used those tools to examine both amplitude-based and time-based methods, an assessment that indicates that fine position-sensing can be achieved with simpler readout designs than are conventionally deployed. This realization can make ubiquitous and inexpensive deployment of special nuclear materials (SNM) detecting technology becomes more feasible because if one can deploy position-sensitive semiconductor detectors with only one or two contacts per side. For this purpose, we have described the delay-line radiation detector and its optimized fabrication. The semiconductor physics were simulated, the results from which guided the fabrication of the guard ring structure and the detector electrode, both of which included metal-field-plates. The measured improvement in the leakage current was confirmed with the fabricated devices, and the structures successfully suppressed soft-breakdown. We also demonstrated that fabricating an asymmetric strip-line structure successfully minimizing the pulse shaping and increases the distance through which one can propagate the information of the deposited charge distribution. With fabricated delay-line detectors we can acquire alpha spectra (Am-241) and gamma spectra (Ba-133, Co-57 and Cd-109). The delay-line detectors can therefore be used to extract the charge information from both ion and gamma-ray interactions. Furthermore, standard charge-sensitive circuits yield high SNR

  7. Familial melanoma associated with dominant ultraviolet radiation sensitivity

    International Nuclear Information System (INIS)

    Ramsay, R.G.; Chen, P.; Imray, F.P.; Kidson, C.; Lavin, M.F.; Hockey, A.

    1982-01-01

    Sensitivity to ultraviolet radiation was studied in lymphoblastoid cell lines derived from 32 members of two families with histories of multiple primary melanomas in several generations. As assayed by colony formation in agar or by trypan blue exclusion following irradiation, cellular sensitivity showed a bimodal distribution. All persons with melanoma or multiple moles were in the sensitive group, while some family members exhibited responses similar to those of controls. Cells from four cases of sporadic melanoma showed normal levels of sensitivity. The data are consistent with a dominantly inherited ultraviolet light sensitivity associated with these examples of familial melanoma. Spontaneous and ultraviolet light-induced sister chromatid exchange frequencies were similar to those in control cell lines. No defect in excision repair was detected in any of the above cell lines, but the sensitive group showed postirradiation inhibition of DNA replication intermediate between controls and an excision-deficient xeroderma pigmentosum cell line

  8. Significance of genetic predisposition and genomic instability for individual sensitivity to radiation. Implications for radiation protection

    International Nuclear Information System (INIS)

    Heller, H.

    2001-01-01

    At its closed-door meeting on 20/21 January 2000 the Radiation Protection Committee dedicated much of its attention to the significance of genetic predisposition and genetic instability for individual radiation sensitivity and to the implication of this for radiation protection. The statements and contributions to the closing plenary discussion touched on many aspects of ethics, personal rights, occupational medicine and insurance issues relating to this subject, all of which extend far beyond the purely technical issues of radiation protection. The present volume contains the lecture manuscripts of the meeting as well as a summarising assessment by the Radiation Protection Committee [de

  9. Sensitivity of clostridium acetobutylicum to oxygen and ionizing radiation

    International Nuclear Information System (INIS)

    Sozer, A.C.; Adler, H.I.; Machanoff, R.; Haney, S.

    1984-01-01

    The authors are studying the sensitivity of four strains of the obligate anaerobe, Clostridium acetobutylicum, to oxygen and ionizing radiation. Anaerobic bacteria are useful for such studies because of the absence of elaborate oxygen detoxification mechanisms that are found in aerobes. Their experiments make use of sterile membrane fragments from Escherichia coli that rapidly remove molecular oxygen from media and permit growth of anaerobes without the use of reducing agents or anaerobic chambers. Of the four strains examined for sensitivity to ionizing radiation under anaerobic conditions, one has an LD/sub 50/ of -- 25 krads and the others have an LD/sub 50/ of -- 7 krads. The radiation resistant strain is also relatively resistant to oxygen exposure. Sensitivity to oxygen was determined by diluting cells in buffer at 28 0 and bubbling with air. An exposure to air for 40 min induced only slight inactivation in the radiation resistant strain. All strains are capable of removing oxygen from complex media but there is no apparent correlation between this oxygen consuming reaction and inactivation by either oxygen or radiation

  10. Radiation-sensitive compounds and methods of using same

    International Nuclear Information System (INIS)

    DeMajistre, R.

    1977-01-01

    Novel diacrylates are prepared by reacting a monohydroxylated acrylic monomer with a polyisocyanate. The reaction product may be polymerized by subjecting to ionizing irradiation, actinic light or to free radical catalysis to form a useful coating material. The diacrylates may also be copolymerized with other radiation sensitive materials

  11. Sensitivity of glaciation in the arid subtropical Andes to changes in temperature, precipitation, and solar radiation

    Science.gov (United States)

    Vargo, L. J.; Galewsky, J.; Rupper, S.; Ward, D. J.

    2018-04-01

    The subtropical Andes (18.5-27 °S) have been glaciated in the past, but are presently glacier-free. We use idealized model experiments to quantify glacier sensitivity to changes in climate in order to investigate the climatic drivers of past glaciations. We quantify the equilibrium line altitude (ELA) sensitivity (the change in ELA per change in climate) to temperature, precipitation, and shortwave radiation for three distinct climatic regions in the subtropical Andes. We find that in the western cordillera, where conditions are hyper-arid with the highest solar radiation on Earth, ELA sensitivity is as high as 34 m per % increase in precipitation, and 70 m per % decrease in shortwave radiation. This is compared with the eastern cordillera, where precipitation is the highest of the three regions, and ELA sensitivity is only 10 m per % increase in precipitation, and 25 m per % decrease in shortwave radiation. The high ELA sensitivity to shortwave radiation highlights the influence of radiation on mass balance of high elevation and low-latitude glaciers. We also consider these quantified ELA sensitivities in context of previously dated glacial deposits from the regions. Our results suggest that glaciation of the humid eastern cordillera was driven primarily by lower temperatures, while glaciations of the arid Altiplano and western cordillera were also influenced by increases in precipitation and decreases in shortwave radiation. Using paleoclimate records from the timing of glaciation, we find that glaciation of the hyper-arid western cordillera can be explained by precipitation increases of 90-160% (1.9-2.6× higher than modern), in conjunction with associated decreases in shortwave radiation of 7-12% and in temperature of 3.5 °C.

  12. High sensitivity MOSFET-based neutron dosimetry

    International Nuclear Information System (INIS)

    Fragopoulou, M.; Konstantakos, V.; Zamani, M.; Siskos, S.; Laopoulos, T.; Sarrabayrouse, G.

    2010-01-01

    A new dosemeter based on a metal-oxide-semiconductor field effect transistor sensitive to both neutrons and gamma radiation was manufactured at LAAS-CNRS Laboratory, Toulouse, France. In order to be used for neutron dosimetry, a thin film of lithium fluoride was deposited on the surface of the gate of the device. The characteristics of the dosemeter, such as the dependence of its response to neutron dose and dose rate, were investigated. The studied dosemeter was very sensitive to gamma rays compared to other dosemeters proposed in the literature. Its response in thermal neutrons was found to be much higher than in fast neutrons and gamma rays.

  13. Correlation of radiation sensitivity and nitrofurantoin sensitivity of Escherichia coli K-12

    International Nuclear Information System (INIS)

    Kloeck, K.

    1981-01-01

    The Uvr- and rec-mutants of E.coli K-12 have been tested with a view to their radiation- and nitrofuration sensitivity. The tests showed that all mutants tested were more radiation- and NF-sensitive than the wild type AB 1157. When the NF-sensitivity had been compared to the UV- and X-ray sensitivity it became obvious that the NF-sensitivity is correlated to the UV-sensitivity. Studies carried out with regard to the time dependence of the NF-effect on E.coli showed that the effect of NF on E. Coli became weaker after about 1 1/2 to 2 hours. That is possibly caused by the fact that the E. coli bacteria succeed in reducing the NF to an inactive form. By means of nitrosoguanidine mutants of E-coli AB 1157 had been induced and by means of the Replicite Plating Method, NF-sensible mutants had been isolated from the plutonium mixture. Among the mutants which had been isolated by this method, 74% had been more UV-sensitive than the wild type and 55% more X-ray sensitive. Thus NF-sensitive mutants have not necessarily to be considered as rec-mutants as there are also uvr-mutants in the mixture. (orig.) [de

  14. Radiation sensitivity of T-lymphocytes from immunodeficient wasted mice

    International Nuclear Information System (INIS)

    Padilla, M.; Libertin, C.; Krco, C.; Woloschak, G.E.

    1990-01-01

    Mice with the autosomal recessive gene wasted (wst/wst) exhibit neurologic disorders, reduced mucosal immune responses, and abnormal DNA repair mechanisms. The wst/wst mouse has been proposed as a murine model for the human disorder ataxia telangiectasia. Experiments were designed to examine the sensitivity of T-cells from wasted mice to ionizing radiation. Results demonstrated that T-cell clones derived from wasted mice are more sensitive to the killing effects of gamma-rays than similar T-cell clones from control mice. Bulk thymocyte and splenic cell cultures demonstrated similar radiation sensitivity. Both thymic and splenic lymphocytes from wasted mice also expressed low proliferative responses to mitogenic stimulation with concanavalin A (Con A) that could not be attributed to an absence or reduction in T-cell number. However, following activation with Con A, cell cultures exhibited a marked decrease in the percentage of Thyl + cells in wasted mice, in contrast to cultures from control mice in which significant increases in Thyl + cells were observed. Furthermore, when cells were treated with gamma-rays in combination with Con A, Thyl + cells were decreased in control spleen and thymus, but were elevated in similarly treated wasted cultures. These changes were accompanied by an increase in cell volume in T-cells from wasted but not from control mice. These results describe the sensitivity of T-cells from wasted mice to ionizing radiation; in addition, they suggest that the wst/wst abnormality may be associated with cell cycle aberrancies

  15. DNA-nuclear matrix interactions and ionizing radiation sensitivity

    International Nuclear Information System (INIS)

    Schwartz, J.L.; Vaughan, A.T.M.

    1993-01-01

    The association between inherent ionizing radiation sensitivity and DNA supercoil unwinding in mammalian cells suggests that the organization of the DNA in chromosomes plays an important role in radiation responses. In this paper, a model is proposed which suggests that these DNA unwinding alterations reflect differences in the attachment of DNA to the nuclear matrix. In radioresistant cells, the MAR structure might exist in a more stable, open configuration, limiting DNA unwinding following strand break induction and influencing the rate and nature of DNA double-strand break rejoining

  16. DNA-nuclear matrix interactions and ionizing radiation sensitivity

    International Nuclear Information System (INIS)

    Schwartz, J.L.; Chicago Univ., IL; Vaughan, A.T.M.

    1993-01-01

    The association between inherent ionizing radiation sensitivity and DNA supercoil unwinding in mammalian cells suggests that the DNA-nuclear matrix attachment region (MAR) plays an important role in radiation response. In radioresistant cells, the MAR structure may exist in a more stable, open configuration, limiting DNA unwinding following strand break induction and maintaining DNA ends in close proximity for more rapid and accurate rejoining. In addition, the open configuration at these matrix attachment sites may serve to facilitate rapid DNA processing of breaks by providing (1) sites for repair proteins to collect and (2) energy to drive enzymatic reactions

  17. CHEMICAL VAPOUR DEPOSITION FROM A RADIATION-SENSITIVE PRECURSOR

    DEFF Research Database (Denmark)

    2017-01-01

    The present invention relates in one aspect to a method of depositing a thin film on a substrate by chemical vapour deposition (CVD) from a radiation-sensitive precursor substance. The method comprises the steps of: (i) placing the substrate in a reaction chamber of a CVD system; (ii) heating...... heating pulse followed by an idle period; (iii) during at least one of the idle periods, providing a pressure pulse of precursor substance inside the reaction chamber by feeding at least one precursor substance to the reaction chamber so as to establish a reaction partial pressure for thin film deposition...... is formed. According to a further aspect, the invention relates to a chemical vapour deposition (CVD) system for depositing a thin film onto a substrate using precursor substances containing at least one radiation sensitive species....

  18. Enhanced sensitivity of the RET proto-oncogene to ionizing radiation in vitro.

    Science.gov (United States)

    Volpato, Claudia Béu; Martínez-Alfaro, Minerva; Corvi, Raffaella; Gabus, Coralie; Sauvaigo, Sylvie; Ferrari, Pietro; Bonora, Elena; De Grandi, Alessandro; Romeo, Giovanni

    2008-11-01

    Exposure to ionizing radiation is a well-known risk factor for a number of human cancers, including leukemia and thyroid cancer. It has been known for a long time that exposure of cells to radiation results in extensive DNA damage; however, a small number of studies have tried to explain the mechanisms of radiation-induced carcinogenesis. The high prevalence of RET/PTC rearrangements in patients who have received external radiation, and the evidence of in vitro induction of RET rearrangements in human cells, suggest an enhanced sensitivity of the RET genomic region to damage by ionizing radiation. To assess whether RET is indeed more sensitive to radiations than other genomic regions, we used a COMET assay coupled with fluorescence in situ hybridization, which allows the measurement of DNA fragmentation in defined genomic regions of single cells. We compared the initial DNA damage of the genomic regions of RET, CXCL12/SDF1, ABL, MYC, PLA2G2A, p53, and JAK2 induced by ionizing radiation in both a lymphoblastoid and a fetal thyroid cell line. In both cell lines, RET fragmentation was significantly higher than in other genomic regions. Moreover, a differential distribution of signals within the COMET was associated with a higher percentage of RET fragments in the tail. RET was more susceptible to fragmentation in the thyroid-derived cells than in lymphoblasts. This enhanced susceptibility of RET to ionizing radiation suggests the possibility of using it as a radiation exposure marker.

  19. Genetic and epigenetic features in radiation sensitivity. Part I: Cell signalling in radiation response

    International Nuclear Information System (INIS)

    Bourguignon, Michel H.; Gisone, Pablo A.; Perez, Maria R.; Michelin, Severino; Dubner, Diana; Giorgio, Marina di; Carosella, Edgardo D.

    2005-01-01

    Recent progress especially in the field of gene identification and expression has attracted greater attention to genetic and epigenetic susceptibility to cancer, possibly enhanced by ionising radiation. It has been proposed that the occurrence and severity of the adverse reactions to radiation therapy are also influenced by such genetic susceptibility. This issue is especially important for radiation therapists since hypersensitive patients may suffer from adverse effects in normal tissues following standard radiation therapy, while normally sensitive patients could receive higher doses of radiation offering a better likelihood of cure for malignant tumours. This paper, the first of two parts, reviews the main mechanisms involved in cell response to ionising radiation. DNA repair machinery and cell signalling pathways are considered and their role in radiosensitivity is analysed. The implication of non-targeted and delayed effects in radiosensitivity is also discussed. (orig.)

  20. Age dependent radiation sensitivity of eggs of Dysdercus koenigii Fabricius

    International Nuclear Information System (INIS)

    Harwalkar, M.R.

    1992-01-01

    Eggs of Dysdercus koenigii Fabricius aged 0 to 2, 24, 48 and 72 hr were irradiated with X-ray doses ranging between 3 to 15 Gy to determine radiation sensitivity. It was observed that age of the eggs greatly influenced their response to radiation treatment. A dose of 6 Gy was required to prevent hatching of 0 to 2 hr old eggs but older eggs (24 and 48 hr) required 9 and 15 Gy, respectively, to bring about the same effect. At all the doses hatchability of 72 hr old irradiated eggs was much higher than those irradiated at younger age. Survival of nymphs emerging from 72 hr irradiated eggs at different dose levels was found to be dose dependent. Percentage of nymphs metamorphosing into adults decreased with increasing radiation dose received at the embryonic stage. (author). 21 refs., 2 figs

  1. Changes in bacterial radiation sensitivity due to deuterium substitution

    International Nuclear Information System (INIS)

    Strauss, A.; Weiss, H.

    1985-01-01

    The influence of deuterium substitution for hydrogen on radiation sensitivity was measured under various conditions for E. coli B/r irradiated by 450 kev electrons in single intense pulses. Cells were grown in a nutrient medium made from a deuterium oxide based solution. They were suspended in a D/sub 2/O based buffered saline and plated in thin aqueous layers on membrane filters and irradiated in 100% N/sub 2/ or 100% O/sub 2/. Comparisons were made to cells similarly plated and irradiated but grown instead in a water based nutrient medium and suspended in either a water based or a D/sub 2/O based buffered saline. For the conventionally grown cells, D/sub 2/O increased the radiation sensitivity in both gases by about 10%. For cells grown and suspended with D/sub 2/O based media, a 50% reduction of radiation sensitivity was found with both gas and an increased extrapolation number was observed. In this latter method, deuterium is more fully substituted for hydrogen in the molecular substrate of the cell. These cells were also irradiated over a temperature range of 2 0 C to 43 0 C after being suspended in deuterated ethanol. Speculations for the changes induced by the substitution are presented

  2. How far is cancer cured by radiation sensitization?

    International Nuclear Information System (INIS)

    Ando, Koichi; Sasaki, Takehito; Ikeda, Hiroshi

    1990-01-01

    Some types of cancer are not cured by radiation alone in view of histology, location, and size. In facing so-called radioresistant cancer, antineoplastic agents, hypoxic cell sensitizers, biological response modifiers, or hyperthermia are used in combination with radiation, with the aim of cancer cure. First of all, this chapter discusses the subject of 'what is tumor cure by radiation therapy'. Current conditions of the aforementioned combined modalities and the future perspectives are presented. The following subjects are covered: (1) tumor control - significance of the number of stem cells; (2) biological evaluation of chemo-radiotherapy with cisplatin; (3) clinical results and experience with combination of radiotherapy and radiosensitizers; (4) radiosensitization with hypoxic cell radiosensitizers - present status (5) hypoxic cell radiosensitizers - present status and problems from the viewpoint of clinical radiotherapy; (6) thermal radiosensitization in vitro and its implications for radiotherapy; (7) clinical assessment of thermoradiotherapy for breast cancer and cancer of the urinary bladder; (8) interactions of radiation and biological response modifiers in the treatment of malignant tumor; (9) improvement in the effects of radiation therapy with biological response modifiers. (N.K.)

  3. Phase sensitive diffraction sensor for high sensitivity refractive index measurement

    Science.gov (United States)

    Kumawat, Nityanand; Varma, Manoj; Kumar, Sunil

    2018-02-01

    In this study a diffraction based sensor has been developed for bio molecular sensing applications and performing assays in real time. A diffraction grating fabricated on a glass substrate produced diffraction patterns both in transmission and reflection when illuminated by a laser diode. We used zeroth order I(0,0) as reference and first order I(0,1) as signal channel and conducted ratiometric measurements that reduced noise by more than 50 times. The ratiometric approach resulted in a very simple instrumentation with very high sensitivity. In the past, we have shown refractive index measurements both for bulk and surface adsorption using the diffractive self-referencing approach. In the current work we extend the same concept to higher diffraction orders. We have considered order I(0,1) and I(1,1) and performed ratiometric measurements I(0,1)/I(1,1) to eliminate the common mode fluctuations. Since orders I(0,1) and I(1,1) behaved opposite to each other, the resulting ratio signal amplitude increased more than twice compared to our previous results. As a proof of concept we used different salt concentrations in DI water. Increased signal amplitude and improved fluid injection system resulted in more than 4 times improvement in detection limit, giving limit of detection 1.3×10-7 refractive index unit (RIU) compared to our previous results. The improved refractive index sensitivity will help significantly for high sensitivity label free bio sensing application in a very cost-effective and simple experimental set-up.

  4. High energy radiation from neutron stars

    International Nuclear Information System (INIS)

    Ruderman, M.

    1985-04-01

    Topics covered include young rapidly spinning pulsars; static gaps in outer magnetospheres; dynamic gaps in pulsar outer magnetospheres; pulse structure of energetic radiation sustained by outer gap pair production; outer gap radiation, Crab pulsar; outer gap radiation, the Vela pulsar; radioemission; and high energy radiation during the accretion spin-up of older neutron stars. 26 refs., 10 figs

  5. Genetic and epigenetic features in radiation sensitivity. Part II: implications for clinical practice and radiation protection

    International Nuclear Information System (INIS)

    Bourguignon, Michel H.; Gisone, Pablo A.; Perez, Maria R.; Michelin, Severino; Dubner, Diana; Giorgio, Marina di; Carosella, Edgardo D.

    2005-01-01

    Recent progress especially in the field of gene identification and expression has attracted greater attention to the genetic and epigenetic susceptibility to cancer, possibly enhanced by ionising radiation. This issue is especially important for radiation therapists since hypersensitive patients may suffer from adverse effects in normal tissues following standard radiation therapy, while normally sensitive patients could receive higher doses of radiation, offering a better likelihood of cure for malignant tumours. Although only a small percentage of individuals are ''hypersensitive'' to radiation effects, all medical specialists using ionising radiation should be aware of the aforementioned progress in medical knowledge. The present paper, the second of two parts, reviews human disorders known or strongly suspected to be associated with hypersensitivity to ionising radiation. The main tests capable of detecting such pathologies in advance are analysed, and ethical issues regarding genetic testing are considered. The implications for radiation protection of possible hypersensitivity to radiation in a part of the population are discussed, and some guidelines for nuclear medicine professionals are proposed. (orig.)

  6. Targeting Nucleophosmin 1 Represents a Rational Strategy for Radiation Sensitization

    Energy Technology Data Exchange (ETDEWEB)

    Sekhar, Konjeti R. [Department of Radiation Oncology, Vanderbilt University School of Medicine, Nashville, Tennessee (United States); Benamar, Mouadh [Department of Radiation Oncology, University of Virginia School of Medicine, Charlottesville, Virginia (United States); Venkateswaran, Amudhan; Sasi, Soumya [Department of Radiation Oncology, Vanderbilt University School of Medicine, Nashville, Tennessee (United States); Penthala, Narsimha R.; Crooks, Peter A. [Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, Arkansas (United States); Hann, Stephen R. [Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee (United States); Geng, Ling [Department of Radiation Oncology, Vanderbilt University School of Medicine, Nashville, Tennessee (United States); Balusu, Ramesh [Department of Internal Medicine, University of Kansas Medical Center, Kansas City, Kansas (United States); Abbas, Tarek [Department of Radiation Oncology, University of Virginia School of Medicine, Charlottesville, Virginia (United States); Freeman, Michael L., E-mail: michael.freeman@vanderbilt.edu [Department of Radiation Oncology, Vanderbilt University School of Medicine, Nashville, Tennessee (United States)

    2014-08-01

    Purpose: To test the hypothesis that small molecule targeting of nucleophosmin 1 (NPM1) represents a rational approach for radiosensitization. Methods and Materials: Wilde-type and NPM1-deficient mouse embryo fibroblasts (MEFs) were used to determine whether radiosensitization produced by the small molecule YTR107 was NPM1 dependent. The stress response to ionizing radiation was assessed by quantifying pNPM1, γH2AX, and Rad51 foci, neutral comet tail moment, and colony formation. NPM1 levels in a human-derived non-small-cell lung cancer (NSCLC) tissue microarray (TMA) were determined by immunohistochemistry. YTR107-mediated radiosensitization was assessed in NSCLC cell lines and xenografts. Results: Use of NPM1-null MEFs demonstrated that NPM1 is critical for DNA double- strand break (DSB) repair, that loss of NPM1 increases radiation sensitivity, and that YTR107-mediated radiosensitization is NPM1 dependent. YTR107 was shown to inhibit NPM1 oligomerization and impair formation of pNPM1 irradiation-induced foci that colocalized with γH2AX foci. Analysis of the TMA demonstrated that NPM1 is overexpressed in subsets of NSCLC. YTR107 inhibited DNA DSB repair and radiosensitized NSCLC lines and xenografts. Conclusions: These data demonstrate that YTR107-mediated targeting of NPM1 impairs DNA DSB repair, an event that increases radiation sensitivity.

  7. Research on Paramecium aurelia sensitivity factors to natural ionizing radiations

    International Nuclear Information System (INIS)

    Croute, F.; Soleilhavoup, J.P.; Gros, N.; Planel, H.

    1976-01-01

    Previous results have demonstrated that the proliferative activity of Paramecium aurelia is linked to the level of natural ionizing radiations since this activity is decreased under radiation protection (lead cell) and increased under chronic exposure to very low dose of 60 Co gamma rays. The results of this investigation indicate that cell sensitivity in spite of variations in natural irradiation levels can be isolated; they are called 'radioresistant' in opposition to 'radiosensitive' cells which present the other response. These characters are being retained for 9 months after the strains have been isolated. On the other hand, in the case of radiosensitive strains, it has been demonstrated that autogamy affected the cell response to background irradiation; no response at all occured on the very day when autogamy took place, but it reached a maximum level 8 days approximately after autogamy. Moreover, it has been proved that the catalase activity of Paramecium aurelia is higher than those already studied in other cell varieties. This great amount of catalase, which seems to vary with the age of cultures after autogamy, could act on Paramecium sensitivity to very low radiation doses [fr

  8. Targeting Nucleophosmin 1 Represents a Rational Strategy for Radiation Sensitization

    International Nuclear Information System (INIS)

    Sekhar, Konjeti R.; Benamar, Mouadh; Venkateswaran, Amudhan; Sasi, Soumya; Penthala, Narsimha R.; Crooks, Peter A.; Hann, Stephen R.; Geng, Ling; Balusu, Ramesh; Abbas, Tarek; Freeman, Michael L.

    2014-01-01

    Purpose: To test the hypothesis that small molecule targeting of nucleophosmin 1 (NPM1) represents a rational approach for radiosensitization. Methods and Materials: Wilde-type and NPM1-deficient mouse embryo fibroblasts (MEFs) were used to determine whether radiosensitization produced by the small molecule YTR107 was NPM1 dependent. The stress response to ionizing radiation was assessed by quantifying pNPM1, γH2AX, and Rad51 foci, neutral comet tail moment, and colony formation. NPM1 levels in a human-derived non-small-cell lung cancer (NSCLC) tissue microarray (TMA) were determined by immunohistochemistry. YTR107-mediated radiosensitization was assessed in NSCLC cell lines and xenografts. Results: Use of NPM1-null MEFs demonstrated that NPM1 is critical for DNA double- strand break (DSB) repair, that loss of NPM1 increases radiation sensitivity, and that YTR107-mediated radiosensitization is NPM1 dependent. YTR107 was shown to inhibit NPM1 oligomerization and impair formation of pNPM1 irradiation-induced foci that colocalized with γH2AX foci. Analysis of the TMA demonstrated that NPM1 is overexpressed in subsets of NSCLC. YTR107 inhibited DNA DSB repair and radiosensitized NSCLC lines and xenografts. Conclusions: These data demonstrate that YTR107-mediated targeting of NPM1 impairs DNA DSB repair, an event that increases radiation sensitivity

  9. Effect of ethanol of the radiation sensitivity of human hemoglobin

    International Nuclear Information System (INIS)

    Szweda-Lewandowska, Z.; Puchala, M.

    1981-01-01

    Radiation sensitivity of oxy-, deoxy-, and methemoglobin (HbOs, Hbbj, and MetHb) in water solutions containing 0.2 M ethanol and in ethanol-free solutions was compared. Radiation sensitivity was estimated on the basis of changes in absorbance at the Soret band (a = 430 nm for deoxyhemoglobin), changes in the absorbance ration Avqv/Avwt determined after conversion of irradiated preparations to methemoglobin, and changes in the value of parameters describing the reaction of hemoglobin oxygenation. The protection coefficient p of hemoglobin by ethanol (ratio of a change in the absence of ethanol to that in its presence) calculated from changes in absorbance at the Soret band equaled about 1.5 at a 4-Mrad dose in all bases except MetHb irradiated in air for which p was much higher (about 3.2). The protection coefficient p' calculated from Dtx values for changes in Avchemically bondv/Avwt equaled 2.2 for HbOs, and 2.8 for MetHb for preparations irradiated in air; p' = 1.7 for Hbbj and 1.8 for MetHb for preparations irradiated under argon. On the basis of these results, the role of /sup ./OH radicals and oxygen in the radiation damage of hemoglobin is discussed

  10. High sensitivity optical molecular imaging system

    Science.gov (United States)

    An, Yu; Yuan, Gao; Huang, Chao; Jiang, Shixin; Zhang, Peng; Wang, Kun; Tian, Jie

    2018-02-01

    Optical Molecular Imaging (OMI) has the advantages of high sensitivity, low cost and ease of use. By labeling the regions of interest with fluorescent or bioluminescence probes, OMI can noninvasively obtain the distribution of the probes in vivo, which play the key role in cancer research, pharmacokinetics and other biological studies. In preclinical and clinical application, the image depth, resolution and sensitivity are the key factors for researchers to use OMI. In this paper, we report a high sensitivity optical molecular imaging system developed by our group, which can improve the imaging depth in phantom to nearly 5cm, high resolution at 2cm depth, and high image sensitivity. To validate the performance of the system, special designed phantom experiments and weak light detection experiment were implemented. The results shows that cooperated with high performance electron-multiplying charge coupled device (EMCCD) camera, precision design of light path system and high efficient image techniques, our OMI system can simultaneously collect the light-emitted signals generated by fluorescence molecular imaging, bioluminescence imaging, Cherenkov luminance and other optical imaging modality, and observe the internal distribution of light-emitting agents fast and accurately.

  11. UV- and gamma-radiation sensitive mutants of Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Jiang, C.Z.; Yen, C.N.; Cronin, K.; Mitchell, D.; Britt, A.B.

    1997-01-01

    Arabidopsis seedlings repair UV-induced DNA damage via light-dependent and -independent pathways. The mechanism of the ''dark repair'' pathway is still unknown. To determine the number of genes required for dark repair and to investigate the substrate-specificity of this process we isolated mutants with enhanced sensitivity to UV radiation in the absence of photoreactivating light. Seven independently derived UV sensitive mutants were isolated from an EMS-mutagenized population. These fell into six complementation groups, two of which (UVR1 and UVH1) have previously been defined. Four of these mutants are defective in the dark repair of UV-induced pyrimidine [6-4] pyrimidinone dimers. These four mutant lines are sensitive to the growth-inhibitory effects of gamma radiation, suggesting that this repair pathway is also involved in the repair of some type of gamma-induced DNA damage product. The requirement for the coordinate action of several different gene products for effective repair of pyrimidine dimers, as well as the nonspecific nature of the repair activity, is consistent with nucleotide excision repair mechanisms previously described in Saccharomyces cerevisiae and nonplant higher eukaryotes and inconsistent with substrate-specific base excision repair mechanisms found in some bacteria, bacteriophage, and fungi. (author)

  12. SENSITIVITY OF THE CUMIN SEEDS ASSOCIATED FUNGI TO GAMMA RADIATION

    International Nuclear Information System (INIS)

    BOTROS, H.W.; HELAL, I.M.; EL TOBGY, K.M.K.

    2008-01-01

    The present study was carried out to investigate the sensitivity of fungi associated to cumin seeds for gamma radiation. In this regard, the isolated seed associated fungi from the cumin seeds were fifteen fungal species belonging to five genera. The fungal species concerning, Aspergillus ochraceus, Fusarium oxysporium and Aspergillus flavus were the predominant fungi in percentages of 17.8, 15.83 and 12.78 %, respectively. Aspergillus ochraceus was the most effective prevalent fungi on the seed germination causing highest percentage of seed invasion followed by Fusarium oxysporium and Aspergillus flavus. The amylolytic, proteolytic and lipolytic activity and mycotoxin production of the three predominant fungi were negatively influenced by gamma radiation when exposed to doses of 1.0 , 1.5 , 2.5 , 3.5 , 5.0 and 7.5 kGy a behaviour which was parallel to the inhibition in the amount of growth by gamma irradiation

  13. High-LET radiation carcinogenesis

    International Nuclear Information System (INIS)

    Fry, R.J.M.; Powers-Risius, P.; Alpen, E.L.; Ainsworth, E.J.

    1985-01-01

    The dose-response curves for the induction of tumors by high-LET radiation are complex and are insufficiently understood. There is no model or formulation to describe the dose-response relationship over a range 0 to 100 rad. Evidence suggests that at doses below 20 rad the response is linear, at least for life shortening and some tumor systems. Thus, limiting values of RBEs for the induction of cancer in various tissues can be determined, but it will require sufficient data obtained at low single doses or with small fractions. The results obtained from experiments with heavy ions indicate an initial linear response with a plateauing of the curve at a tumor incidence level that is dependent on the type of tissue. The RBE values for the heavy ions using 60 Co gamma rays as the reference radiation increase with the estimated LET from 4 for 4 H to about 27 for 56 Fe, 40 Ar. The dose-responses and RBEs for 56 Fe and 40 Ar are similar to those for fission neutrons. These findings suggest the possibility that the effectiveness for tumor induction reaches a maximum. 26 refs., 4 figs., 2 tabs

  14. Sensitization of ultraviolet radiation damage in bacteria and mammalian cells

    International Nuclear Information System (INIS)

    Fisher, G.J.; Watts, M.E.; Patel, K.B.; Adams, G.E.

    1978-01-01

    Bacteria (Serratia marcescens) and mammalian cells (Chinese hamsters V79-379A) were irradiated in monolayers with ultraviolet light at 254 nm or 365 nm in the presence or absence of radiosensitizing drugs. At 254 nm, killing is very efficient (Dsub(37) approximately equal 1 J m -2 exposure, or approximately equal 6 x 10 4 photons absorbed by DNA per bacterium), and sensitizers have no effect. At 365 nm, cells are not killed in buffer, but are inactivated in the presence of nifurpipone or misonidazole. Lethal exposures (approximately equal 5 x 10 3 J m -2 at 10 nM misonidazole) correspond to about 10 7 photons absorbed by sensitizer molecules per bacterium. Toxicity of stable photoproducts of the drugs is not involved, nor is oxygen required. Hence the transient species formed by photo-excitation of radiosensitizer molecules are capable of killing cells in the absence of other types of radiation damage. (author)

  15. Heterogeneous catalysis in highly sensitive microreactors

    DEFF Research Database (Denmark)

    Olsen, Jakob Lind

    This thesis present a highly sensitive silicon microreactor and examples of its use in studying catalysis. The experimental setup built for gas handling and temperature control for the microreactor is described. The implementation of LabVIEW interfacing for all the experimental parts makes...

  16. Aluminum nanocantilevers for high sensitivity mass sensors

    DEFF Research Database (Denmark)

    Davis, Zachary James; Boisen, Anja

    2005-01-01

    We have fabricated Al nanocantilevers using a simple, one mask contact UV lithography technique with lateral and vertical dimensions under 500 and 100 nm, respectively. These devices are demonstrated as highly sensitive mass sensors by measuring their dynamic properties. Furthermore, it is shown ...

  17. Sensitivity of surface temperature to radiative forcing by contrail cirrus in a radiative-mixing model

    Directory of Open Access Journals (Sweden)

    U. Schumann

    2017-11-01

    Full Text Available Earth's surface temperature sensitivity to radiative forcing (RF by contrail cirrus and the related RF efficacy relative to CO2 are investigated in a one-dimensional idealized model of the atmosphere. The model includes energy transport by shortwave (SW and longwave (LW radiation and by mixing in an otherwise fixed reference atmosphere (no other feedbacks. Mixing includes convective adjustment and turbulent diffusion, where the latter is related to the vertical component of mixing by large-scale eddies. The conceptual study shows that the surface temperature sensitivity to given contrail RF depends strongly on the timescales of energy transport by mixing and radiation. The timescales are derived for steady layered heating (ghost forcing and for a transient contrail cirrus case. The radiative timescales are shortest at the surface and shorter in the troposphere than in the mid-stratosphere. Without mixing, a large part of the energy induced into the upper troposphere by radiation due to contrails or similar disturbances gets lost to space before it can contribute to surface warming. Because of the different radiative forcing at the surface and at top of atmosphere (TOA and different radiative heating rate profiles in the troposphere, the local surface temperature sensitivity to stratosphere-adjusted RF is larger for SW than for LW contrail forcing. Without mixing, the surface energy budget is more important for surface warming than the TOA budget. Hence, surface warming by contrails is smaller than suggested by the net RF at TOA. For zero mixing, cooling by contrails cannot be excluded. This may in part explain low efficacy values for contrails found in previous global circulation model studies. Possible implications of this study are discussed. Since the results of this study are model dependent, they should be tested with a comprehensive climate model in the future.

  18. Development of an underwater high sensitivity Cherenkov detector: Sea Urchin

    International Nuclear Information System (INIS)

    Camerini, U.; McGibney, D.; Roberts, A.

    1982-01-01

    The need for a high gain, high sensitivity Cherenkov light sensor to be used in a deep underwater muon and neutrino detector (DUMAND) array has led to the design of the Sea Urchin detector. In this design a spherical photocathode PMTis optically coupled through a glass hemisphere to a large number of glass spines, each of which is filled with a wavelength-shifting (WLS) solution of a high quantum efficiency phosphor. The Cherenkov radiation is absorbed in the spine, isotropically re-radiated at a longer wavelength, and a fraction of the fluorescent light is internally reflected in the spine, and guided to the photomultiplier concentrically located in the glass hemisphere. Experiments measuring the optical characteristics of the spines and computer programs simulating light transformation and detection cross sections are described. Overall optical gains in the range 5-10 are achieved. The WLS solution is inexpensive, and may have other applications. (orig.)

  19. Single photon detector with high polarization sensitivity.

    Science.gov (United States)

    Guo, Qi; Li, Hao; You, LiXing; Zhang, WeiJun; Zhang, Lu; Wang, Zhen; Xie, XiaoMing; Qi, Ming

    2015-04-15

    Polarization is one of the key parameters of light. Most optical detectors are intensity detectors that are insensitive to the polarization of light. A superconducting nanowire single photon detector (SNSPD) is naturally sensitive to polarization due to its nanowire structure. Previous studies focused on producing a polarization-insensitive SNSPD. In this study, by adjusting the width and pitch of the nanowire, we systematically investigate the preparation of an SNSPD with high polarization sensitivity. Subsequently, an SNSPD with a system detection efficiency of 12% and a polarization extinction ratio of 22 was successfully prepared.

  20. Methods and tools for the evaluation of the sensitivity to natural radiations of advanced integrated circuits

    International Nuclear Information System (INIS)

    Peronnard, P.

    2009-10-01

    Atmospheric neutrons, whose fluxes and energies dependent on the altitude, the sun activity and the geographic coordinates, have been identified as being capable to provoke SEE (Single Event Effects), by indirect ionisation, in integrated devices issued from advanced manufacturing processes (nano-metric devices). This concerns not only avionics but also applications operating at ground level. The evaluation of the sensitivity to SEE provoked by natural radiation becomes thus a mandatory step during the selection of devices devoted to be included in applications requiring high reliability. The sensitivity to SEE can be mitigated by different approaches at different levels from manufacturing level (use of particular process technologies such as SOI - Silicon On Isolator -) to the system level (hardware/software redundancy). Independently of the adopted hardening approach, the so-called radiation ground testing are mandatory to evaluate the error rates of a device or a system. During such tests, the DUT (Device Under Test) is exposed to a flux of particles while it performs a given activity. For SEU (Single Event Upsets) radiation ground testing, two main strategies exist: static test: the circuit areas which are supposed to be sensitive to SEUs (registers, memories,...) are initialized with a reference pattern. The content of the sensitive area is periodically compared to the reference pattern to identify potential SEU. Dynamic test: the DUT performs an activity representative of the one it will execute during the final application. Static test: strategies are frequently adopted as they provide the intrinsic sensitivity, in terms of the average number of particles needed to provoke an SEU, of different sensitive areas of the device. From such a strategy can thus be obtained a 'worst case estimation' of the device sensitivity. This thesis aims at giving a description and validating the methodologies required to estimate the sensitivity to radiations of two types of

  1. Radiation effects of high and low doses

    International Nuclear Information System (INIS)

    El-Naggar, A.M.

    1998-01-01

    The extensive proliferation of the uses and applications of atomic and nuclear energy resulted in possible repercussions on human health. The prominent features of the health hazards that may be incurred after exposure to high and low radiation doses are discussed. The physical and biological factors involved in the sequential development of radiation health effects and the different cellular responses to radiation injury are considered. The main criteria and features of radiation effects of high and low doses are comprehensively outlined

  2. Study on the application of sensitizing and protective agent in the process of radiation chemistry

    International Nuclear Information System (INIS)

    Kamal, Z.

    1976-01-01

    The role of sensitizing agent and protective agent in the process of radiation chemistry is studied. Direct and indirect radiation effects on bio molecules, molecular and sensitizing agent mechanism, electron activities as the basis for sensitizing agent mechanism, protective agent mechanism on irradiated macro molecules, and kinds of protective and sensitizing agents, are discussed. (RUW)

  3. Sensitivity study of cloud/radiation interaction using a second order turbulence radiative-convective model

    International Nuclear Information System (INIS)

    Kao, C.Y.J.; Smith, W.S.

    1993-01-01

    A high resolution one-dimensional version of a second order turbulence convective/radiative model, developed at the Los Alamos National Laboratory, was used to conduct a sensitivity study of a stratocumulus cloud deck, based on data taken at San Nicolas Island during the intensive field observation marine stratocumulus phase of the First International Satellite Cloud Climatology Program (ISCCP) Regional Experiment (FIRE IFO), conducted during July, 1987. Initial profiles for liquid water potential temperature, and total water mixing ratio were abstracted from the FIRE data. The dependence of the diurnal behavior in liquid water content, cloud top height, and cloud base height were examined for variations in subsidence rate, sea surface temperature, and initial inversion strength. The modelled diurnal variation in the column integrated liquid water agrees quite well with the observed data, for the case of low subsidence. The modelled diurnal behavior for the height of the cloud top and base show qualitative agreement with the FIRE data, although the overall height of the cloud layer is about 200 meters too high

  4. Sensitivity to low-dose radiation in radiosensitive ''wasted'' mice

    International Nuclear Information System (INIS)

    Paunesku, T.; Protic, M.; Woloschak, G. E.

    1999-01-01

    Mice homozygous for the autosomal recessive wasted mutation (wst/wst) have abnormalities in T-lymphocytes and in the anterior motor neuron cells of the spinal cord, leading to sensitivity to low doses of ionizing radiation, hind limb paralysis, and immunodeficiency. This defect results in a failure to gain weight by 20 days and death at 28 days of age. The wasted mutation (previously mapped to mouse chromosome 2) is shown to be a 3-bp deletion in a T-cell-specific (and perhaps motor-neuron-specific) regulatory region (promoter) of the proliferating cell nuclear antigen (PCNA) gene on mouse chromosome 2. A regulatory element is also shown to be important in PCNA expression in T-lymphocytes and motor neuron cells afflicted by the 3-bp deletion in the PCNA promoter. The model is as follows: Absence of PCNA expression in the thymuses (and motor neurons) of wasted mice causes cellular apoptosis; this absence of expression is mediated by a positive transactor that can bind to the wild-type but not the wasted mutant PCNA promoter; the bound protein induces late expression of PCNA in T-lymphocytes and prevents onset of radiation sensitivity in the cells

  5. The sensitivity of human mesenchymal stem cells to ionizing radiation

    International Nuclear Information System (INIS)

    Chen, M.-F.; Lin, C.-T.; Chen, W.-C.; Yang, C.-T.; Chen, C.-C.; Liao, S.-K.; Liu, J.M.; Lu, C.-H.; Lee, K.-D.

    2006-01-01

    Purpose: Recent studies have shown that mesenchymal stem cells (MSCs) obtained from bone marrow transplantation patients originate from the host. This clinical observation suggests that MSCs in their niches could be resistant to irradiation. However, the biologic responses of bone marrow MSCs to irradiation have rarely been described in the literature. Methods and Materials: In this study, human bone marrow-derived, clonally expanded MSCs were used to investigate their sensitivity to irradiation in vitro, and the cellular mechanisms that may facilitate resistance to irradiation. The human lung cancer cell line A549 and the breast cancer cell line HCC1937 were used as controls for radiosensitivity; the former line has been shown to be radioresistant and the latter radiosensitive. We then examined their in vitro biologic changes and sensitivities to radiation therapy. Results: Our results suggest that MSCs are characterized as resistant to irradiation. Several cellular mechanisms were demonstrated that may facilitate resistance to irradiation: ATM protein phosphorylation, activation of cell-cycle checkpoints, double-strand break repair by homologous recombination and nonhomologous end joining (NHEJ), and the antioxidant capacity for scavenging reactive oxygen species. Conclusions: As demonstrated, MSCs possess a better antioxidant reactive oxygen species-scavenging capacity and active double-strand break repair to facilitate their radioresistance. These findings provide a better understanding of radiation-induced biologic responses in MSCs and may lead to the development of better strategies for stem cell treatment and cancer therapy

  6. High blood pressure and visual sensitivity

    Science.gov (United States)

    Eisner, Alvin; Samples, John R.

    2003-09-01

    The study had two main purposes: (1) to determine whether the foveal visual sensitivities of people treated for high blood pressure (vascular hypertension) differ from the sensitivities of people who have not been diagnosed with high blood pressure and (2) to understand how visual adaptation is related to standard measures of systemic cardiovascular function. Two groups of middle-aged subjects-hypertensive and normotensive-were examined with a series of test/background stimulus combinations. All subjects met rigorous inclusion criteria for excellent ocular health. Although the visual sensitivities of the two subject groups overlapped extensively, the age-related rate of sensitivity loss was, for some measures, greater for the hypertensive subjects, possibly because of adaptation differences between the two groups. Overall, the degree of steady-state sensitivity loss resulting from an increase of background illuminance (for 580-nm backgrounds) was slightly less for the hypertensive subjects. Among normotensive subjects, the ability of a bright (3.8-log-td), long-wavelength (640-nm) adapting background to selectively suppress the flicker response of long-wavelength-sensitive (LWS) cones was related inversely to the ratio of mean arterial blood pressure to heart rate. The degree of selective suppression was also related to heart rate alone, and there was evidence that short-term changes of cardiovascular response were important. The results suggest that (1) vascular hypertension, or possibly its treatment, subtly affects visual function even in the absence of eye disease and (2) changes in blood flow affect retinal light-adaptation processes involved in the selective suppression of the flicker response from LWS cones caused by bright, long-wavelength backgrounds.

  7. Methylation of the ATM promoter in glioma cells alters ionizing radiation sensitivity

    International Nuclear Information System (INIS)

    Roy, Kanaklata; Wang, Lilin; Makrigiorgos, G. Mike; Price, Brendan D.

    2006-01-01

    Glioblastomas are among the malignancies most resistant to radiation therapy. In contrast, cells lacking the ATM protein are highly sensitive to ionizing radiation. The relationship between ATM protein expression and radiosensitivity in 3 glioma cell lines was examined. T98G cells exhibited normal levels of ATM protein, whereas U118 and U87 cells had significantly lower levels of ATM and increased (>2-fold) sensitivity to ionizing radiation compared to T98G cells. The ATM promoter was methylated in U87 cells. Demethylation by azacytidine treatment increased ATM protein levels in the U87 cells and decreased their radiosensitivity. In contrast, the ATM promoter in U118 cells was not methylated. Further, expression of exogenous ATM did not significantly alter the radiosensitivity of U118 cells. ATM expression is therefore heterogeneous in the glioma cells examined. In conclusion, methylation of the ATM promoter may account for the variable radiosensitivity and heterogeneous ATM expression in a fraction of glioma cells

  8. Synthesis and mechanistic studies of phosphoraziridines as radiation sensitizers

    International Nuclear Information System (INIS)

    Perlman, M.E.

    1982-01-01

    Ethyl bis(2,2-dimethyl-1-aziridinyl)phosphinyl carbamate (AB-132) and ethyl bis(2,2-dimethyl-1-aziridinyl)phosphinate (AB-163) are potent antitumor agents which have also been demonstrated to be radiation sensitizers in experimental and clinical studies. Monophenyl aziridines and various isomers of diphenylaziridines were utilized. Optically active 2-phenyl aziridine was also employed in order to prepare diastereomerically homogeneous compounds. Para-substituted phenylaziridines were prepared as well and converted to the corresponding phosphoraziridines in order to probe electronic effects of such substituents on biological activity and chemical reactivity. The hydrolysis of 2,2-dimethylaziridine-type compounds including AB-132 and AB-163 was studied by NMR in order to gain further insight into the hydrolytic intermediates which may be responsible for the known cholinesterase inhibition and the suspected phosphorylation of radiation-damaged DNA. Comparative reactivities of the compounds prepared in this study with p-nitrobenzylpyridine were investigated so as to provide some indication of potential alkylating activity, in the hope of obtaining a correlation with biological activity. Electron spin resonance was utilized to study the effects of radiation on phosphoraziridine crystals

  9. High energy particle accelerators as radiation Sources

    Energy Technology Data Exchange (ETDEWEB)

    Abdelaziz, M E [National Center for Nuclear Safety and Radiation Vontrol, Atomic Energy Authority, Cairo (Egypt)

    1997-12-31

    Small accelerators in the energy range of few million electron volts are usually used as radiation sources for various applications, like radiotherapy, food irradiation, radiation sterilization and in other industrial applications. High energy accelerators with energies reaching billions of electron volts also find wide field of applications as radiation sources. Synchrotrons with high energy range have unique features as radiation sources. This review presents a synopsis of cyclic accelerators with description of phase stability principle of high energy accelerators with emphasis on synchrotrons. Properties of synchrotron radiation are given together with their applications in basic and applied research. 13 figs.,1 tab.

  10. Radiation metabolomics : a window to high throughput radiation biodosimetry

    International Nuclear Information System (INIS)

    Rana, Poonam

    2016-01-01

    In the event of an intentional or accidental release of ionizing radiation in a densely populated area, timely assessment and triage of the general population for radiation exposure is critical. In particular, a significant number of victims may sustain radiation injury, which increases mortality and worsens the overall prognosis of victims from radiation trauma. Availability of a high-throughput noninvasive in vivo biodosimetry tool for assessing the radiation exposure is of particular importance for timely diagnosis of radiation injury. In this study, we describe the potential NMR techniques in evaluating the radiation injury. NMR is the most versatile technique that has been extensively used in the diverse fields of science since its discovery. NMR and biomedical sciences have been going hand in hand since its application in clinical imaging as MRI and metabolic profiling of biofluids was identified. We have established an NMR based metabonomic and in vivo spectroscopy approach to analyse and identify metabolic profile to measure metabolic fingerprint for radiation exposure. NMR spectroscopy experiments were conducted on urine and serum samples collected from mice irradiated with different doses of radiation. Additionally, in vivo NMR spectroscopy was also performed in different region of brains post irradiation in animal model. A number of metabolites associated with energy metabolism, gut flora metabolites, osmolytes, amino acids and membrane metabolism were identified in serum and urine metabolome. Our results illustrated a metabolic fingerprint for radiation exposure that elucidates perturbed physiological functions. Quantitative as well as multivariate analysis/assessment of these metabolites demonstrated dose and time dependent toxicological effect. In vivo spectroscopy from brain showed radiation induced changes in hippocampus region indicating whole body radiation had striking effect on brain metabolism as well. The results of the present work lay a

  11. Improvements to a neutral radiation detection and position sensitive process and devices

    International Nuclear Information System (INIS)

    Charpak, Georges; Nguyen, N.H.; Policarpo, Armando.

    1977-01-01

    This invention aims to provide a neutral radiation position sensitive process and device providing a spatial radiation satisfactory for most medical applications and an energy radiation that cannot be reached by gas detectors based on proportional counters or by scintillation counters. Only solid state detectors can compete with respect to energy resolution. The detector described enables large areas to be covered which cannot be reached at accessible costs by solid state detectors. With this aim in view, the invention suggests an incident neutral radiation and position sensitive process, particularly soft gamma and X radiations, whereby photoelectrons are made to form by incident radiation action on gas atoms contained in an enclosure. By means of an electric field, the electrons are diverted towards a space undergoing an electric field high enough in value to create photons by exciting gas atoms and returning them to the de-excited state. The photons are collected, through a transparent window, on a layer of a material for converting such photons into scintillations in the near or visible UV spectrum and the barycentre of the scintillations is positioned on the layer, for instance by photomultipliers or ionization detectors. According to another aspect of the invention, it suggests a detection and position sensitive device comprising (generally downstream of a collimator with a grid of inlet holes) a leak tight containment fitted with an inlet window transparent to incident radiations, filled with a gas producing electrons by interaction with the incident radiation, and fitted with electrodes for generating an electric field to divert the electrons to a space for creating secondary photons [fr

  12. Advances in radiation biology: Relative radiation sensitivities of human organ systems. Volume 12

    International Nuclear Information System (INIS)

    Lett, J.T.; Altman, K.I.; Ehmann, U.K.; Cox, A.B.

    1987-01-01

    This volume is a thematically focused issue of Advances in Radiation Biology. The topic surveyed is relative radiosensitivity of human organ systems. Topics considered include relative radiosensitivities of the thymus, spleen, and lymphohemopoietic systems; relative radiosensitivities of the small and large intestine; relative rediosensitivities of the oral cavity, larynx, pharynx, and esophagus; relative radiation sensitivity of the integumentary system; dose response of the epidermal; microvascular, and dermal populations; relative radiosensitivity of the human lung; relative radiosensitivity of fetal tissues; and tolerance of the central and peripheral nervous system to therapeutic irradiation

  13. Advances in radiation biology: Relative radiation sensitivities of human organ systems. Volume 12

    Energy Technology Data Exchange (ETDEWEB)

    Lett, J.T.; Altman, K.I.; Ehmann, U.K.; Cox, A.B.

    1987-01-01

    This volume is a thematically focused issue of Advances in Radiation Biology. The topic surveyed is relative radiosensitivity of human organ systems. Topics considered include relative radiosensitivities of the thymus, spleen, and lymphohemopoietic systems; relative radiosensitivities of the small and large intestine; relative rediosensitivities of the oral cavity, larynx, pharynx, and esophagus; relative radiation sensitivity of the integumentary system; dose response of the epidermal; microvascular, and dermal populations; relative radiosensitivity of the human lung; relative radiosensitivity of fetal tissues; and tolerance of the central and peripheral nervous system to therapeutic irradiation.

  14. Radiographic imaging system for high energy radiation

    International Nuclear Information System (INIS)

    1975-01-01

    A radiographic imaging system for high energy radiation is described utilizing a detector of such radiation and a mask having regions relatively transparent to such radiation and interspersed among regions relatively opaque to such radiation. A relative motion is imparted between the mask and the detector, the detector providing a time varying signal in response to the incident radiation and in response to the relative motion. The time varying signal provides, with the aid of a decoder, an image of a source of such radiation

  15. Radiographic imaging system for high energy radiation

    International Nuclear Information System (INIS)

    Barrett, H.H.

    1976-01-01

    A radiographic imaging system for high energy radiation utilizing a detector of such radiation and a mask having regions relatively transparent to such radiation interspersed among regions relatively opaque to such radiation is described. A relative motion is imparted between the mask and the detector, the detector providing a time varying signal in response to the incident radiation and in response to the relative motion. The time varying signal provides, with the aid of a decoder, an image of a source of such radiation

  16. Position sensitive regions in a generic radiation sensor based on single event upsets in dynamic RAMs

    International Nuclear Information System (INIS)

    Darambara, D.G.; Spyrou, N.M.

    1997-01-01

    Modern integrated circuits are highly complex systems and, as such, are susceptible to occasional failures. Semiconductor memory devices, particularly dynamic random access memories (dRAMs), are subject to random, transient single event upsets (SEUs) created by energetic ionizing radiation. These radiation-induced soft failures in the stored data of silicon based memory chips provide the foundation for a new, highly efficient, low cost generic radiation sensor. The susceptibility and the detection efficiency of a given dRAM device to SEUs is a complicated function of the circuit design and geometry, the operating conditions and the physics of the charge collection mechanisms involved. Typically, soft error rates measure the cumulative response of all sensitive regions of the memory by broad area chip exposure in ionizing radiation environments. However, this study shows that many regions of a dynamic memory are competing charge collection centres having different upset thresholds. The contribution to soft fails from discrete regions or individual circuit elements of the memory device is unambiguously separated. Hence the use of the dRAM as a position sensitive radiation detector, with high spatial resolution, is assessed and demonstrated. (orig.)

  17. High technology for radiation application

    International Nuclear Information System (INIS)

    Iida, Toshiyuki

    2005-03-01

    Fundamentals of radiations, radioactivity, and their applications in recent industrial, medical, agricultural and various research fields are reviewed. The book begins with historical description regarding to discovery of radiation at the end of 19th century and the exploration into the inside of an atom utilizing the radiation discovered, discovery of the neutron which finally leaded to nuclear energy liberation. Developments of radiation sources, including nuclear reactors, and charged-particle accelerators follow with simultaneous description on radiation measurement or detection technology. In medical fields, X-ray diagnosis, interventional radiology (IVR), nuclear medicine (PET and others), and radiation therapy are introduced. In pharmaceutical field, synthesis of labeled compounds and tracer techniques are explained. In industrial application, radiation-reinforced wires and heat-resistant cables whose economic effect can be estimated to amount to more than 10 12 yen, radiation mutation, food irradiation, and applied accelerators such as polymer modifications, decomposition of environmentally harmful substances, and ion-implantations important in semiconductor device fabrication. Finally, problems relating to general public such as radiation education and safety concept are also discussed. (S. Ohno)

  18. Comparative studies on the effect of radiation-sensitizing agents used in radiating VX2 Carcinoma

    International Nuclear Information System (INIS)

    Migita, Hidenobu

    1975-01-01

    The effects of 5-Fu and BUdR as radiation-sensitizing agents macroscopically were investigated in 122 VX2 Carcinomas transplanted into the calves of the hind legs of rabbits. Experimental groups and contrast groups are divided into six as follows: A: No treatment, B: 5-Fu infusion, C: BUdR+Antimetabolite infusion, D: Radiation, E: 5-Fu infusion and radiation, and F: BUdR+Antimetabolite infusion and radiation. The amount of agent given to each was 5 mg/kg/day of 5-Fu and 50 mg/kg/day of BUdR, and the amount of radiation was 300 rad/day. 5-Fu was used as the Antimetabolite, and its amount was one-tenth of that in the 5-Fu Infusion Group. The agent and the radiation were given for five days. 1. In the 300 rad/day Group, the radiation was not enough to result in a complete cure. 2. In the two Agent Infusion Group, 5-Fu and BUdR+Antimetabolite proved to be anti-cancer, but neither of them resulted in effective treatment. 3. The 5-Fu Infusion and Radiation Group, showed a strong degenerative change in the tumor cell and a radiosensitive effect from 5-Fu, but the tumor was not lessened. 4. In the BUdR-Antimetabolite Infusion and Radiation Group, the tumor began to reduce on the third day. On the seventh and fourteenth days, necrosis of the greater part of tumor was seen, and the rest of the tumor cells were found to be in degenerative change. On the twenty first day, no live tumor cell was found, only dead remains of tumor cells. The results were confirmed both macroscopically and histopathologically. 5. BUdR can be expected to be effective in clinical application to oral malignant tumors. (Evans, J.)

  19. The potential sensitivity of tropical plants to increased ultraviolet-B radiation

    International Nuclear Information System (INIS)

    Ziska, L.H.

    1996-01-01

    Little is known concerning the impact of stratospheric ozone depletion and increasing ultraviolet (UV)-B radiation on the phenology and growth of tropical plants. This is because, ostensibly, tropical plants are already exposed to relatively high levels of UV-B radiation (relative to a temperate environment) and should, therefore, possess a greater degree of tolerance to increased UV-B radiation. In this brief review I hope to show that, potentially, direct and indirect effects on photosynthesis, assimilate partitioning, phenology and biomass could occur in both tropical crops (e.g. cassava, rice) and native species (e.g. Cecropia obtusifolia (Bertol. Fl)., Tetramolopium humile (Gray), Nana sandwicensis L.). However, it should be noted that differences in sensitivity to UV-B radiation can be related to experimental conditions, and care should be taken to ensure that the quantity and quality of background solar radiation remains at near ambient conditions. Nevertheless, by integrating current and past studies on the impact of UV-B radiation on tropical species, I hope to be able to demonstrate that photosynthesis, morphology and growth in tropical plants could be directly affected by UV-B radiation and that UV-B radiation may be a factor in species and community dynamics in natural plant populations in the tropics

  20. Low Cost, Low Power, High Sensitivity Magnetometer

    Science.gov (United States)

    2008-12-01

    which are used to measure the small magnetic signals from brain. Other types of vector magnetometers are fluxgate , coil based, and magnetoresistance...concentrator with the magnetometer currently used in Army multimodal sensor systems, the Brown fluxgate . One sees the MEMS fluxgate magnetometer is...Guedes, A.; et al., 2008: Hybrid - LOW COST, LOW POWER, HIGH SENSITIVITY MAGNETOMETER A.S. Edelstein*, James E. Burnette, Greg A. Fischer, M.G

  1. Incoming longwave radiation to melting snow: observations, sensitivity and estimation in Northern environments

    Science.gov (United States)

    Sicart, J. E.; Pomeroy, J. W.; Essery, R. L. H.; Bewley, D.

    2006-11-01

    At high latitudes, longwave radiation can provide similar, or higher, amounts of energy to snow than shortwave radiation due to the low solar elevation (cosine effect and increased scattering due to long atmospheric path lengths). This effect is magnified in mountains due to shading and longwave emissions from the complex topography. This study examines longwave irradiance at the snow surface in the Wolf Creek Research Basin, Yukon Territory, Canada (60° 36N, 134° 57W) during the springs of 2002 and 2004. Incoming longwave radiation was estimated from standard meteorological measurements by segregating radiation sources into clear sky, clouds and surrounding terrain. A sensitivity study was conducted to detect the atmospheric and topographic conditions under which emission from adjacent terrain significantly increases the longwave irradiance. The total incoming longwave radiation is more sensitive to sky view factor than to the temperature of the emitting terrain surfaces. Brutsaert's equation correctly simulates the clear-sky irradiance for hourly time steps using temperature and humidity. Longwave emissions from clouds, which raised longwave radiation above that from clear skies by 16% on average, were best estimated using daily atmospheric shortwave transmissivity and hourly relative humidity. An independent test of the estimation procedure for a prairie site near Saskatoon, Saskatchewan, Canada, indicated that the calculations are robust in late winter and spring conditions. Copyright

  2. In vivo assay of the radiation sensitivity of hypoxic tumour cells. Influence of radiation quality and hypoxic sensitization

    International Nuclear Information System (INIS)

    Porschen, W.; Bosiljanoff, P.; Gewehr, K.; Muehlensiepen, H.; Feinendegen, L.E.

    1977-01-01

    In order to measure quantitatively tumour cell kinetics in living mice, tumour bearing animals (sarcoma-180) received intravenously 5-iodo-2'-deoxyuridine (IUdR), a thymidine analogue, which was labelled with 125 I or with 131 I, both of which can be easily externally counted by their gamma emission. IUdR is stably bound to DNA, reutilization is minimal and the measured activity loss from the tumour later than 50 hours after injection signals cell loss or cell death. The effect of irradiation on euoxic and average tumour cells was studied by sequentially labelling the tumour bearing animals first with 125 IUdR and, 70 hours later, with 131 IUdR. At the time of the second injection the average tumour cell population is labelled by the first injection of 125 IUdR, and the second injection of 131 IUdR nearly exclusively tags the perivascular tumour cells; these are euoxic in contrast to the average tumour cell, a large proportion of which is hypoxic. The radiation-induced activity loss rates from the two labelled tumour cell populations indicate the sensitivities of the two populations. At dose levels that cause identical effects on euoxic cells, the ratio of radiation-induced enhancement of cell loss rates for euoxic cells to average cells was 2.6 for 60 Co gamma radiation, 1.4 for 15MeV neutron irradiation, and 1.0 for alpha irradiation (1.5.MeV). The effect of five hypoxic cell sensitizers was analysed. The sensitization was limited to hypoxic cells, and the most effective drug was Ro-07-0582, showing at the 50% level of maximum effect a dose modifying factor of 1.5. Sensitization was highest when the drug was given 15 min prior to irradiation. Hyperthermia affected nearly exclusively hypoxic cells and showed a dose modifying factor of about 2 when the tumours were heated at 42 0 C for 30 min immediately after irradiation. The resulting enhancement of effect was reduced when hyperthermia was applied prior to irradiation. (author)

  3. Sensitivity of mitochondria of the mouse liver cells to radiation

    International Nuclear Information System (INIS)

    Shima, Akihiro

    1974-01-01

    In order to study the sensitivity of mitochondria (Mt) of the liver cells to radiation, 0.4 mg of riboflavine (RF) was intraperitoneally injected into mice which had been fed RF deficient food for 13 weeks. Three hours later 400 R of X-ray (190 KVP, 25 mA, 0.5 mmCu, 0.5 mmAl filter, FSD 61.5 cm, and HVL 0.80 mmCu) were irradiated to the whole body, and giant Mt of the liver cells were observed. When the liver cells were observed 24 hours after injection, neither giant Mt nor mitotic findings of Mt were found. All Mt observed were small (1.2 μ), although mice received 400 R of X-ray. (Serizawa, K.)

  4. Sensitivity of mitochondria of the mouse liver cells to radiation

    Energy Technology Data Exchange (ETDEWEB)

    Shima, A [Tokyo Univ. (Japan). Faculty of Science

    1974-06-01

    In order to study the sensitivity of mitochondria (Mt) of the liver cells to radiation, 0.4 mg of riboflavine (RF) was intraperitoneally injected into mice which had been fed RF deficient food for 13 weeks. Three hours later 400 R of X-ray (190 KVP, 25 mA, 0.5 mmCu, 0.5 mmAl filter, FSD 61.5 cm, and HVL 0.80 mmCu) were irradiated to the whole body, and giant Mt of the liver cells were observed. When the liver cells were observed 24 hours after injection, neither giant Mt nor mitotic findings of Mt were found. All Mt observed were small (1.2 ..mu..), although mice received 400 R of X-ray.

  5. Radiation and thermal characteristics of mouse lymphoma cells and their radiation-sensitive mutant

    International Nuclear Information System (INIS)

    Baba, Yuji; Yasunaga, Tadamasa; Uozumi, Hideaki; Takahashi, Mutsumasa; Sawada, Shozo.

    1988-01-01

    Radiation and thermal characteristics of L5178Y cells and their radiation-sensitive mutant M10 cells were studied by the colony-forming method and the dye-exclusion method using eosin-Y. Although M10 cells were remarkably radiation-sensitive compared with L5178Y cells, it was diffcult to cause interphase death of M10 after a large dose of irradiation. After heat treatments, L5178Y cells revealed more cell destruction and were stained well by eosin-Y, but it was relatively difficult to produce cell destruction of M10 cells, which showed poor staining by eosin-Y. When assayed by the colony-forming method, M10 cells were also heat-resistant compared to L5178Y. The dye-exclusion rate was closely correlated with cell survival after hyperthermia of L5178Y cells, suggesting that this is a simple method of detecting the thermosensitivity and thermotolerance of cancer cells. The difference in survival of L5178Y cells and M10 cells after combined treatment with gamma irradiation and hyperthermia was smaller than with gamma irradiation alone. It was also found that there was a relationship between radiation-induced interphase death and hyperthermia-induced interphase death, and that interphase death accounted for a major part of cell death caused by hyperthermia in mouse leukemia cells. (author)

  6. Radiation sensitivity of fungal microflora isolated from some pharmaceutical ingredients

    Energy Technology Data Exchange (ETDEWEB)

    Mostafa, S.A. (Ain Shams Univ., Cairo (Egypt). Botany Dept.); El-Zawahry, Y.A.; Abdel All, S.S.

    1983-01-01

    The total number of fungal microflora of D-glucose, NaCl, KCl and their solutions was determined. The fungal isolates were identified as Aspergillus fumigatus. Aspergillus niger; Spicaria divaricate and Spicaria silvatica and their response to ..gamma..-radiation was determined, the most predominant isolate Asp. fumigatus was also the most irradiation resistant. The Dio and the lethal dose were determined for each isolate in a pure spore suspension as well as in the presence of the other isolates. The higher lethal dose values obtained for pure spore suspension as compared to that obtained for the natural fungal flora a D-glucose are discussed in terms of spore clumping. The activity of amylase, protease and L-asparaginase of Asp. fumigatus was examined prior to and after exposure to different doses of ..gamma..-radiation. Though all were inhibited at high doses, the effect was not as drastic as it was on cell viability.

  7. Study on intraoperative radiotherapy applying hyperthermia together with radiation sensitizers for progressive local carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Abe, M; Takahashi, M; Ono, K; Hiraoka, M [Kyoto Univ. (Japan). Faculty of Medicine

    1980-08-01

    Intraoperative radiotherapy for gastric cancer, colonic cancer, pancreatic cancer, cancer of the biliary tract, prostatic carcinoma, cerebral tumor, tumor of soft tissues, and osteosarcoma and its clinical results were described. Basic and clinical studies on effects of both hyperthermia and radiation sensitizers to elevate radiation sensitivity were also described, because effects of intraoperative radiotherapy were raised by applying hyperthermia and hypoxic cell sensitizers.

  8. Radiation sensitivity of Merkel cell carcinoma cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, J.H.; Ramsay, J.R.; Birrell, G.W. [Queensland Institute of Medical Research (Australia)] [and others

    1995-07-30

    Merkel cell carcinoma (MCC), being a small cell carcinoma, would be expected to be sensitive to radiation. Clinical analysis of patients at our center, especially those with macroscopic disease, would suggest the response is quite variable. We have recently established a number of MCC cell lines from patients prior to radiotherapy, and for the first time are in a position to determine their sensitivity under controlled conditions. Some of the MCC lines grew as suspension cultures and could not be single cell cloned; therefore, it was not possible to use clonogenic survival for all cell lines. A tetrazolium based (MTT) assay was used for these lines, to estimate cell growth after {gamma} irradiation. Control experiments were conducted on lymphoblastoid cell lines (LCL) and the adherent MCC line, MCC13, to demonstrate that the two assays were comparable under the conditions used. We have examined cell lines from MCC, small cell lung cancer (SCLC), malignant melanomas, Epstein Barr virus (EBV) transformed lymphocytes (LCL), and skin fibroblasts for their sensitivity to {gamma} irradiation using both clonogenic cell survival and MTT assays. The results show that the tumor cell lines have a range of sensitivities, with melanoma being more resistant (surviving fraction at 2 Gy (SF2) 0.57 and 0.56) than the small cell carcinoma lines, MCC (SF2 range 0.21-0.45, mean SF2 0.30, n = 8) and SCLC (SF2 0.31). Fibroblasts were the most sensitive (SF2 0.13-0.20, mean 0.16, n = 5). The MTT assay, when compared to clonogenic assay for the MCC13 adherent line and the LCL, gave comparable results under the conditions used. Both assays gave a range of SF2 values for the MCC cell lines, suggesting that these cancers would give a heterogeneous response in vivo. The results with the two derivative clones of MCC14 (SF2 for MCC14/1 0.38, MCC14/2 0.45) would further suggest that some of them may develop resistance during clonogenic evolution. 25 refs., 3 figs., 1 tab.

  9. Radiation sensitivity of Merkell cell carcinoma cell lines

    International Nuclear Information System (INIS)

    Leonard, J. Helen; Ramsay, Jonathan R.; Kearsley, John H.; Birrell, Geoff W.

    1995-01-01

    Purpose: Merkel cell carcinoma (MCC), being a small cell carcinoma, would be expected to be sensitive to radiation. Clinical analysis of patients at our center, especially those with macroscopic disease, would suggest the response is quite variable. We have recently established a number of MCC cell lines from patients prior to radiotherapy, and for the first time are in a position to determine their sensitivity under controlled conditions. Methods and Materials: Some of the MCC lines grew as suspension cultures and could not be single cell cloned; therefore, it was not possible to use clonogenic survival for all cell lines. A tetrazolium based (MTT) assay was used for these lines, to estimate cell growth after γ irradiation. Control experiments were conducted on lymphoblastoid cell lines (LCL) and the adherent MCC line, MCC13, to demonstrate that the two assays were comparable under the conditions used. Results: We have examined cell lines from MCC, small cell lung cancer (SCLC), malignant melanomas, Epstein Barr virus (EBV) transformed lymphocytes (LCL), and skin fibroblasts for their sensitivity to γ irradiation using both clonogenic cell survival and MTT assays. The results show that the tumor cell lines have a range of sensitivities, with melanoma being more resistant (surviving fraction at 2 Gy (SF2) 0.57 and 0.56) than the small cell carcinoma lines, MCC (SF2 range 0.21-0.45, mean SF2 0.30, n = 8) and SCLC (SF2 0.31). Fibroblasts were the most sensitive (SF2 0.13-0.20, mean 0.16, n = 5). The MTT assay, when compared to clonogenic assay for the MCC13 adherent line and the LCL, gave comparable results under the conditions used. Conclusion: Both assays gave a range of SF2 values for the MCC cell lines, suggesting that these cancers would give a heterogeneous response in vivo. The results with the two derivative clones of MCC14 (SF2 for MCC14/1 0.38, MCC14/2 0.45) would further suggest that some of them may develop resistance during clonogenic evolution

  10. Studies on radiation-sensitive nonsilver halide materials, (1)

    International Nuclear Information System (INIS)

    Komizu, Hideo; Honda, Koichi; Yabe, Akira; Kawasaki, Masami; Fujii, Etsuo

    1978-01-01

    In order to discover new radiation-sensitive nonsilver halide materials, the coloration based on the formation of Stenhouse salts was studied in the following three systems: (a) furfural-amine/HCl aq/methanol solution, (b) furfural-amine/polyhalogenide/PMMA matrix, (c) furfural-amine/PVC matrix. Firstly, forty-five aromatic amines were surveyed to find out the amines suitable for the color precursors (reactant from furfural and amine) in the system (a). As a result, the five amines, which gave the precursors in good yields by the reaction with furfural, were selected: m-nitroaniline, N-methylaniline, m-methyl-N-methylaniline, aniline, and o-methoxyaniline. Secondly, the coloration induced by electron beam bombardment was studied in the systems (b) and (c) containing the color precursors (the reactants from these amines and furfural). Although the PMMA films containing the color precursors and polyhalogenides were sensitive to electron beam, they were not stable when standing under daylight at room temperature. The PVC films containing the color precursors were very stable and colored to reddish yellow (lambda sub(max) 498 - 545 nm) by electron beam bombardment. The PVC film containing N-methylaniline-furfural was the most sensitive and the increase in absorbance at 498 nm was 0.78 by electron beam bombardment of 60 kV - 7.5 x 10 -7 C/cm 2 . A good linear relationship existed between the degree of coloration and the amounts of electron beam bombardment in the range from 0 to 10 -6 C/cm 2 . (author)

  11. Review of high-sensitivity Radon studies

    Science.gov (United States)

    Wojcik, M.; Zuzel, G.; Simgen, H.

    2017-10-01

    A challenge in many present cutting-edge particle physics experiments is the stringent requirements in terms of radioactive background. In peculiar, the prevention of Radon, a radioactive noble gas, which occurs from ambient air and it is also released by emanation from the omnipresent progenitor Radium. In this paper we review various high-sensitivity Radon detection techniques and approaches, applied in the experiments looking for rare nuclear processes happening at low energies. They allow to identify, quantitatively measure and finally suppress the numerous sources of Radon in the detectors’ components and plants.

  12. Resveratrol sensitization of DU145 prostate cancer cells to ionizing radiation is associated to ceramide increase.

    Science.gov (United States)

    Scarlatti, Francesca; Sala, Giusy; Ricci, Clara; Maioli, Claudio; Milani, Franco; Minella, Marco; Botturi, Marco; Ghidoni, Riccardo

    2007-08-08

    Radiotherapy is an established therapeutic modality for prostate cancer. Since it is well known that radiotherapy is limited due to its severe toxicity towards normal cells at high dose and minimal effect at low dose, the search for biological compounds that increase the sensitivity of tumors cells to radiation may improve the efficacy of therapy. Resveratrol, a natural antioxidant, was shown to inhibit carcinogenesis in animal models, and to block the process of tumor initiation and progression. The purpose of this study was to examine whether or not resveratrol can sensitize DU145, an androgen-independent human prostate cancer cell line, to ionizing radiation. We report here that DU145 cells are resistant to ionizing radiation-induced cell death, but pretreatment with resveratrol significantly enhances cell death. Resveratrol acts synergistically with ionizing radiation to inhibit cell survival in vitro. Resveratrol also potentiates ionizing radiation-induced ceramide accumulation, by promoting its de novo biosynthesis. This confirms ceramide as an effective mediator of the anticancer potential induced by resveratrol.

  13. Gamma radiation induced sensitization and photo-transfer in Mg2SiO4:Tb TLD phosphor

    International Nuclear Information System (INIS)

    Lakshmanan, A.R.; Vohra, K.G.

    1979-01-01

    Mg 2 SiO 4 :Tb TLD phosphor was found to show enhanced TL sensitivity to both gamma and UV radiations after high pre-gamma exposures (>100 R) and a post-annealing treatment at 300 0 C for 1 h. Maximum sensitization factors of 2.8 and 55 were obtained at the pre-expsoure levels of 5.2x10 1 C/kg and 1.3x10 3 C/kg for gamma and UV test radiations respectively. The near constancy of the intensity of the residual TL (RTL) peak at 500 0 C for the sensitized sample with increasing test-gamma exposures has ruled out the re-trapping model proposed earlier for the gamma radiation induced sensitization in this phosphor. The Tsub(max) for the sensitized phosphor was found to occur at a higher temperature compared to that for the virgin phosphor. The dependence of sensitization on RTL was explained qualitatively on the basis of competition between sensitization traps (having higher energy than the dosimetry traps) and RTL traps while capturing the charge carriers generated during the test-gamma exposure. The sensitization observed in this phosphor to UV test radiation was found to be a consequence of the photo-transfer of charge carriers from deep (RTL) traps to the shallow (dosimetry) traps. The reduction in RTL peak (500 0 C) intensity of the sensitized sample with increasing test-UV exposure has demonstrated the photo-transfer mechanism in this phosphor. The TL response of the virgin Mg 2 SiO 4 :Tb phosphor was found to be supralinear to both gamma and UV radiations. The TL response of the sensitized phosphor was found to be linear to gamma radiation and sublinear to UV radiation. (Auth.)

  14. High sensitivity troponin and valvular heart disease.

    Science.gov (United States)

    McCarthy, Cian P; Donnellan, Eoin; Phelan, Dermot; Griffin, Brian P; Enriquez-Sarano, Maurice; McEvoy, John W

    2017-07-01

    Blood-based biomarkers have been extensively studied in a range of cardiovascular diseases and have established utility in routine clinical care, most notably in the diagnosis of acute coronary syndrome (e.g., troponin) and the management of heart failure (e.g., brain-natriuretic peptide). The role of biomarkers is less well established in the management of valvular heart disease (VHD), in which the optimal timing of surgical intervention is often challenging. One promising biomarker that has been the subject of a number of recent VHD research studies is high sensitivity troponin (hs-cTn). Novel high-sensitivity assays can detect subclinical myocardial damage in asymptomatic individuals. Thus, hs-cTn may have utility in the assessment of asymptomatic patients with severe VHD who do not have a clear traditional indication for surgical intervention. In this state-of-the-art review, we examine the current evidence for hs-cTn as a potential biomarker in the most commonly encountered VHD conditions, aortic stenosis and mitral regurgitation. This review provides a synopsis of early evidence indicating that hs-cTn has promise as a biomarker in VHD. However, the impact of its measurement on clinical practice and VHD outcomes needs to be further assessed in prospective studies before routine clinical use becomes a reality. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. High Efficency Lightweight Radiators, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — XC Associates proposes to build on prior work to develop and characterize a very high efficiency, lightweight radiator constructed from high thermal conductivity...

  16. Radiation and heat sensitivity of microflora in mixed spices

    International Nuclear Information System (INIS)

    Alam, M. K.; Choudhury, N.; Chowdhury, N. A.; Youssouf, Q.M.

    1994-01-01

    Spices such as coriander, cumin, turmeric, chilli collected from local market were found to be highly contaminated with bacteria and fungi. A dose of 3 kGy without heat treatment reduced the microbial load from 6 log to 3 log and from 5 log to 2 log units depending on the storage temperature whereas the same dose of radiation combined with heat treatment reduced the microbial load from 6 log to 2 log units and from 4 log to below detectable level depending on storage condition. The combination treated spices retained good organoleptic quality in comparison to that of only irradiated species with higher dose. 11 refs., 2 tables (author)

  17. Highly sensitive high resolution Raman spectroscopy using resonant ionization methods

    International Nuclear Information System (INIS)

    Owyoung, A.; Esherick, P.

    1984-05-01

    In recent years, the introduction of stimulated Raman methods has offered orders of magnitude improvement in spectral resolving power for gas phase Raman studies. Nevertheless, the inherent weakness of the Raman process suggests the need for significantly more sensitive techniques in Raman spectroscopy. In this we describe a new approach to this problem. Our new technique, which we call ionization-detected stimulated Raman spectroscopy (IDSRS), combines high-resolution SRS with highly-sensitive resonant laser ionization to achieve an increase in sensitivity of over three orders of magnitude. The excitation/detection process involves three sequential steps: (1) population of a vibrationally excited state via stimulated Raman pumping; (2) selective ionization of the vibrationally excited molecule with a tunable uv source; and (3) collection of the ionized species at biased electrodes where they are detected as current in an external circuit

  18. Radiation sensitive polymers of oxygen-substituted maleimides and elements containing same

    International Nuclear Information System (INIS)

    Wilson, J.C.

    1977-01-01

    Radiation sensitive polymers comprising from about 1 to 100 mole % of a polymerized maleimide monomer consisting of a hydrocarbon group having from 2 to 20 carbon atoms, preferably a bridged hydrocarbon group having from 6 to 10 carbon atoms and from 0 to about 99 mole % of at least one additional polymerized ethylenically unsaturated monomer are described. The polymers are soluble in organic solvents, possess desirably high glass transition temperatures and are capable of undergoing a photochemical reaction to yield polymers having isocyanate and oxy-substituted cyclopropane moieties which are capable of crosslinking in the presence of active hydrogen-containing compounds. The polymers are useful in radiation sensitive compositions and elements containing same

  19. Radiation distribution sensor with optical fibers for high radiation fields

    International Nuclear Information System (INIS)

    Takada, Eiji; Kimura, Atsushi; Hosono, Yoneichi; Takahashi, Hiroyuki; Nakazawa, Masaharu

    1999-01-01

    Radiation distribution sensors with their feasibilities have been described in earlier works. However, due to large radiation induced transmission losses in optical fibers, especially in the visible wavelength region, it has been difficult to apply these techniques to high radiation fields. In this study, we proposed a new concept of optical fiber based radiation distribution measurements with near infrared (IR) emission. Near IR scintillators were attached to the ends of optical fibers, where the fibers were bundled and connected to an N-MOS line sensor or a cooled CCD camera. From the measurements of each area density, the radiation levels at the positions of the scintillators can be known. The linearity between the gamma dose rate at each scintillator and the registered counts has been examined. For correcting the radiation induced loss effects, we applied the Optical Time Domain Reflectometry technique to measure the loss distribution and from the results, a possibility for correction of the loss effect has been demonstrated. The applicable dose rate range was evaluated to be from 0.1 to 10 3 Gy/h. This system can be a promising tool as a flexible dose rate distribution monitor in radiation facilities like nuclear plants and accelerator facilities. (author)

  20. Variation in radiation sensitivity and repair kinetics in different parts of the spinal cord

    International Nuclear Information System (INIS)

    Adamus-Gorka, Magdalena; Brahme, Anders; Mavroidis, Panayiotis; Lind, Bengt K.

    2008-01-01

    Background. The spinal cord, known for its strongly serial character and high sensitivity to radiation even when a small segment is irradiated, is one of the most critical organs at risk to be spared during radiation therapy. To compare the sensitivity of different parts of the spinal cord, data for radiation myelopathy have been used. Material and methods. In the present study, the relative seriality model was fitted to two different datasets of clinical radiation myelitis concerning cervical spinal cord after treating 248 patients for head and neck cancer and thoracic spinal cord after treating 43 patients with lung carcinoma. The maximum likelihood method was applied to fit the clinical data. The model parameters and their 68% confidence intervals were calculated for each dataset. The α/β ratio for the thoracic cord was also was also found to be 0.9 (0-3.0) Gy. Results. The dose-response curve for the more sensitive cervical myelopathy is well described by the parameters D 50 =55.9 (54.8-57.1) Gy, γ=6.9 (5.0-9.2), s=0.13 (0.07-0.24), whereas the thoracic myelopathy is described by the parameters D 50 =75.5 (70.5-80.8) Gy, γ=1.1 (0.6-1.6), s=36 (3.3-8). Discussion and conclusions. Large differences in radiation response between the cervical and thoracic region of spinal cord are thus observed: cervical myelopathy seems to be characterized by medium seriality, while thoracic spinal cord is characterized by a highly serial dose-response. The much steeper dose-response curve for cervical spinal cord myelopathy can be interpreted as a higher number of functional subunits consistent with a higher amount of white matter close to the brain

  1. Experimental microdosimetry in high energy radiation fields

    International Nuclear Information System (INIS)

    Spurny, F.; Bednar, J.; Vlcek, B.; Bottollier-Depois, J.-F.; Molokanov, A.G.

    2000-01-01

    correspond to the interactions of secondary panicles created by primary radiation are close to the sensitive volume of the equipment. The comparison of both methods was performed in the field on board aircraft and in high energy reference fields. it was found that the microdosimetric distributions observed agreed at least qualitatively, a quantitative agreement of integral dosimetric values was found as well. The measurements in proton beams were performed in several points along the Bragg curve. Actually, we were able to observe the influence of primary beam contamination due to the filtration as well as due to the secondary particle created during the penetration of beams in the phantome. The relevance of such data for the radiotherapy application of high energy protons is evident. It was proved that both method can give relevant and useful information on the microdosimetric distributions in complex beams and fields of high energy panicles. The further development of this approach is in progress in our laboratories. (author)

  2. Radiation effects on materials in high-radiation environments

    International Nuclear Information System (INIS)

    Weber, W.J.; Mansur, L.K.; Clinard, F.W. Jr.; Parkin, D.M.

    1991-01-01

    A workshop on Radiation Effects on Materials in High-Radiation Environments was held in Salt Lake City, Utah (USA) from August 13 to 15, 1990 under the auspices of the Division of Materials Sciences, Office of Basic Energy Sciences, US Department of Energy. The workshop focused on ceramics, alloys, and intermetallics and covered research needs and capabilities, recent experimental data, theory, and computer simulations. It was concluded that there is clearly a continuing scientific and technological need for fundamental knowledge on the underlying causes of radiation-induced property changes in materials. Furthermore, the success of many current and emerging nuclear-related technologies critically depend on renewed support for basic radiation-effects research, irradiation facilities, and training of scientists. The highlights of the workshop are reviewed and specific recommendations are made regarding research needs. (orig.)

  3. Three-dimensional, position-sensitive radiation detection

    Science.gov (United States)

    He, Zhong; Zhang, Feng

    2010-04-06

    Disclosed herein is a method of determining a characteristic of radiation detected by a radiation detector via a multiple-pixel event having a plurality of radiation interactions. The method includes determining a cathode-to-anode signal ratio for a selected interaction of the plurality of radiation interactions based on electron drift time data for the selected interaction, and determining the radiation characteristic for the multiple-pixel event based on both the cathode-to-anode signal ratio and the electron drift time data. In some embodiments, the method further includes determining a correction factor for the radiation characteristic based on an interaction depth of the plurality of radiation interactions, a lateral distance between the selected interaction and a further interaction of the plurality of radiation interactions, and the lateral positioning of the plurality of radiation interactions.

  4. Radiation sensitivity of certain egyptian isolates of yersinia enterocolitica

    International Nuclear Information System (INIS)

    El-Zzawahry, Y.A.; Youssef, Y.A.; Awny; El-Sherif, W.M.

    1987-01-01

    An irradiation dose of 2 KGy was sufficient to destroy the cells of the six tested isolates of pathogenic yersinia enterocolitica and reduce the population of two isolates by log cycles, while the irradiation dose of reduced the number of cells by about 4 to 5 log cycles. Dose response curves of yersinia enterocolitica indicate that radio-sterile ground beef used as suspending medium was more protective for the tested isolates against the damaging effect of radiation than sterile nutrient broth. The cells of yersinia enterocolitica suspended in radio-sterile ground beef with few exception were more injured in presence of either 3% NaCl or 1% Nano 2 in the recovery medium than those suspended in a sterile nutrient broth. It has been found that, in general, irradiated cells of all isolates of yersinia enterocolitica were more sensitive to 3% Na No 2 in the recovery medium. The results indicated that there was no viable counts obtained for the three tested local isolates of yersinia enterocolitica at the lethal dose of 2.5 KGy during a storage period of 1 week up to 5 weeks at 4 degree C for both media, sterile nutrient broth and radio-sterile gound beef. Furthermore, significant effect of different increasing doses of gamma irradiation was obtained on the different chemical constituents of yersinia enterocolitica

  5. CALDER: High-sensitivity cryogenic light detectors

    International Nuclear Information System (INIS)

    Casali, N.; Bellini, F.; Cardani, L.

    2017-01-01

    The current bolometric experiments searching for rare processes such as neutrinoless double-beta decay or dark matter interaction demand for cryogenic light detectors with high sensitivity, large active area and excellent scalability and radio-purity in order to reduce their background budget. The CALDER project aims to develop such kind of light detectors implementing phonon-mediated Kinetic Inductance Detectors (KIDs). The goal for this project is the realization of a 5 × 5 cm"2 light detector working between 10 and 100mK with a baseline resolution RMS below 20 eV. In this work the characteristics and the performances of the prototype detectors developed in the first project phase will be shown.

  6. High sensitivity amplifier/discriminator for PWC's

    International Nuclear Information System (INIS)

    Hansen, S.

    1983-01-01

    The facility support group at Fermilab is designing and building a general purpose beam chamber for use in several locations at the laboratory. This pwc has 128 wires per plane spaced 1 mm apart. An initial production of 25 signal planes is anticipated. In proportional chambers, the size of the signal depends exponentially on the charge stored per unit of length along the anode wire. As the wire spacing decreases, the capacitance per unit length decreases, thereby requiring increased applied voltage to restore the necessary charge per unit length. In practical terms, this phenomenon is responsible for difficulties in constructing chambers with less than 2 mm wire spacing. 1 mm chambers, therefore, are frequently operated very near to their breakdown point and/or a high gain gas containing organic compounds such as magic gas is used. This argon/iso-butane mixture has three drawbacks: it is explosive when exposed to the air, it leaves a residue on the wires after extended use and is costly. An amplifier with higher sensitivity would reduce the problems associated with operating chambers with small wire spacings and allow them to be run a safe margin below their breakdown voltage even with an inorganic gas mixture such as argon/CO2, this eliminating the need to use magic gas. Described here is a low cost amplifier with a usable threshold of less than 0.5 μA. Data on the performance of this amplifier/discriminator in operation on a prototype beam chamber are given. This data shows the advantages of the high sensitivity of this design

  7. A trial of ACNU and radiation therapy with sensitizing agents for malignant gliomas

    Energy Technology Data Exchange (ETDEWEB)

    Kawano, Hirokazu; Hayashi, Minoru; Satoh, Kazufumi; Ishii, Hisamasa; Nakatsugawa, Shigekazu; Ishii, Yasushi (Fukui Medical School, Yoshida, Fukui (Japan))

    1989-11-01

    Twelve cases of malignant gliomas (anaplastic astrocytoma 4, glioblatoma 8, recurrent 3, primary 9) were treated with ACNU and radiation with sensitizing agents after the surgical removal of the tumor. BUdR, Vidarabine (Ara-A), Aciclovir (ACV) were applied for sensitizing agents. BUdR was administrated intraarterially prior to radiation (380 rad, two times a week), and Ara-A and ACV intravenously during and after the radiation. Total dosage of the radiation was 50-60 Grey for each case. All recurrent and eight primary patients died. The mean survival time of the recurrent patients was 17.7 months, while that of the primary patients was 13.4 months. One of the primary patients was glioblastoma and is still surviving more than 24 months by now. The complete response (CR) rate of the primary tumor patients observed by computerized tomography (CT) scan was 5/9. We can expect the availability of this trial for malignant gliomas because of high CR rate in primary tumor cases. (author).

  8. Predictive Biomarkers of Radiation Sensitivity in Rectal Cancer

    Science.gov (United States)

    Tut, Thein Ga

    repair (MMR) proteins, the insufficiency of which is characteristic of CRCs with microsatellite instability (MSI). MSI may enable unlimited replicative potential of malignant cell that leads to radiation injury resistance. Therefore, these proteins were characterized in both CRC cell lines (MMR proteins) and different (core and invasive front) rectal cancer tissues (Plk1, gammaH2AX and MMR proteins) exposed to radiation. Histopathological grading of tumour regression was performed following radiotherapy in rectal cancer as a marker of radiotherapy response and a surrogate indicator of patient prognosis. Though MMR protein expressions correlated with improved in vitro cell survival following radiation, these findings could only be partially replicated in patient tissue samples. This may not be entirely unexpected, given intratumoural heterogeneity in genetic profiles and oxygenation between individual cancer cells, their interaction with stromal environment and a multitude of other factors that cannot be adequately replicated in cell line experiments. In our rectal cancer patient cohort, histopathological regression following radiotherapy did appear to correlate with better clinical outcome, but certainly no replacement for the routine pTNM staging with which it was compared. Overexpression of Plk1 in the primary rectal cancer also correlates with poor tumour regression and reduced overall survival. High level of gammaH2AX correlates with higher tumour stage, perineural invasion and vascular invasion. However, interpretation of the results is limited by the small number of positivity amongst the cohort, with respect to gammaH2AX and MMR proteins. The combined analysis of all the proteins examined in this thesis revealed no interactions, possibly suggesting these biomarkers act individually within the DDR pathway, rather than in a demonstrably interdependent manner. Though our results are mixed, finding biomarkers predictive of radiation response is nonetheless critical

  9. High sensitivity thermal sensors on insulating diamond

    Energy Technology Data Exchange (ETDEWEB)

    Job, R. [Fernuniversitaet Hagen (Gesamthochschule) (Germany). Electron. Devices; Denisenko, A.V. [Fernuniversitaet Hagen (Gesamthochschule) (Germany). Electron. Devices; Zaitsev, A.M. [Fernuniversitaet Hagen (Gesamthochschule) (Germany). Electron. Devices; Melnikov, A.A. [Belarussian State Univ., Minsk (Belarus). HEII and FD; Werner, M. [VDI/VDE-IT, Teltow (Germany); Fahrner, W.R. [Fernuniversitaet Hagen (Gesamthochschule) (Germany). Electron. Devices

    1996-12-15

    Diamond is a promising material to develop sensors for applications in harsh environments. To increase the sensitivity of diamond temperature sensors the effect of thermionic hole emission (TE) over an energetic barrier formed in the interface between highly boron-doped p-type and intrinsic insulating diamond areas has been suggested. To study the TE of holes a p-i-p diode has been fabricated and analyzed by electrical measurements in the temperature range between 300 K and 700 K. The experimental results have been compared with numerical simulations of its electrical characteristics. Based on a model of the thermionic emission of carriers into an insulator it has been suggested that the temperature sensitivity of the p-i-p diode on diamond is strongly affected by the re-emission of holes from a group of donor-like traps located at a level of 0.7-1.0 eV above the valence band. The mechanism of thermal activation of the current includes a spatial redistribution of the potential, which results in the TE regime from a decrease of the immobilized charge of the ionized traps within the i-zone of the diode and the correspondent lowering of the forward biased barrier. The characteristics of the p-i-p diode were studied with regard to temperature sensor applications. The temperature coefficient of resistance (TCR=-0.05 K{sup -1}) for temperatures above 600 K is about four times larger than the maximal attainable TCR for conventional boron-doped diamond resistors. (orig.)

  10. Transportable high sensitivity small sample radiometric calorimeter

    International Nuclear Information System (INIS)

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

    1998-01-01

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

  11. On the sensitivity of a helicopter combustor wall temperature to convective and radiative thermal loads

    International Nuclear Information System (INIS)

    Berger, S.; Richard, S.; Duchaine, F.; Staffelbach, G.; Gicquel, L.Y.M.

    2016-01-01

    Highlights: • Coupling of LES, DOM and conduction is applied to an industrial combustor. • Thermal sensitivity of the combustor to convection and radiation is investigated. • CHT based on LES is feasible in an industrial context with acceptable CPU costs. • Radiation heat fluxes are of the same order of magnitude that the convective ones. • CHT with radiation are globally in good agreement with thermocolor test. - Abstract: The design of aeronautical engines is subject to many constraints that cover performance gain as well as increasingly sensitive environmental issues. These often contradicting objectives are currently being answered through an increase in the local and global temperature in the hot stages of the engine. As a result, hot spots could appear causing a premature aging of the combustion chamber. Today, the characterization of wall temperatures is performed experimentally by complex thermocolor tests in advanced phases of the design process. To limit such expensive experiments and integrate the knowledge of the thermal environment earlier in the design process, efforts are currently performed to provide high fidelity numerical tools able to predict the combustion chamber wall temperature including the main physical phenomena: combustion, convection and mixing of hot products and cold flows, radiative transfers as well as conduction in the solid parts. In this paper, partitioned coupling approaches based on a Large Eddy Simulation (LES) solver, a Discrete Ordinate Method radiation solver and an unsteady conduction code are used to investigate the sensitivity of an industrial combustor thermal environment to convection and radiation. Four computations including a reference adiabatic fluid only simulation, Conjugate Heat Transfer, Radiation-Fluid Thermal Interaction and fully coupled simulations are performed and compared with thermocolor experimental data. From the authors knowledge, such comparative study with LES has never been published. It

  12. Histone Deacetylase Inhibitor Induced Radiation Sensitization Effects on Human Cancer Cells after Photon and Hadron Radiation Exposure

    Directory of Open Access Journals (Sweden)

    Ariungerel Gerelchuluun

    2018-02-01

    Full Text Available Suberoylanilide hydroxamic acid (SAHA is a histone deacetylase inhibitor, which has been widely utilized throughout the cancer research field. SAHA-induced radiosensitization in normal human fibroblasts AG1522 and lung carcinoma cells A549 were evaluated with a combination of γ-rays, proton, and carbon ion exposure. Growth delay was observed in both cell lines during SAHA treatment; 2 μM SAHA treatment decreased clonogenicity and induced cell cycle block in G1 phase but 0.2 μM SAHA treatment did not show either of them. Low LET (Linear Energy Transfer irradiated A549 cells showed radiosensitization effects on cell killing in cycling and G1 phase with 0.2 or 2 μM SAHA pretreatment. In contrast, minimal sensitization was observed in normal human cells after low and high LET radiation exposure. The potentially lethal damage repair was not affected by SAHA treatment. SAHA treatment reduced the rate of γ-H2AX foci disappearance and suppressed RAD51 and RPA (Replication Protein A focus formation. Suppression of DNA double strand break repair by SAHA did not result in the differences of SAHA-induced radiosensitization between human cancer cells and normal cells. In conclusion, our results suggest SAHA treatment will sensitize cancer cells to low and high LET radiation with minimum effects to normal cells.

  13. Fiber optics in high dose radiation fields

    International Nuclear Information System (INIS)

    Partin, J.K.

    1985-01-01

    A review of the behavior of state-of-the-art optical fiber waveguides in high dose (greater than or equal to 10 5 rad), steady state radiation fields is presented. The influence on radiation-induced transmission loss due to experimental parameters such as dose rate, total dose, irradiation history, temperature, wavelength, and light intensity, for future work in high dose environments are given

  14. Physics of intense, high energy radiation effects.

    Energy Technology Data Exchange (ETDEWEB)

    Hjalmarson, Harold Paul; Hartman, E. Frederick; Magyar, Rudolph J.; Crozier, Paul Stewart

    2011-02-01

    This document summarizes the work done in our three-year LDRD project titled 'Physics of Intense, High Energy Radiation Effects.' This LDRD is focused on electrical effects of ionizing radiation at high dose-rates. One major thrust throughout the project has been the radiation-induced conductivity (RIC) produced by the ionizing radiation. Another important consideration has been the electrical effect of dose-enhanced radiation. This transient effect can produce an electromagnetic pulse (EMP). The unifying theme of the project has been the dielectric function. This quantity contains much of the physics covered in this project. For example, the work on transient electrical effects in radiation-induced conductivity (RIC) has been a key focus for the work on the EMP effects. This physics in contained in the dielectric function, which can also be expressed as a conductivity. The transient defects created during a radiation event are also contained, in principle. The energy loss lead the hot electrons and holes is given by the stopping power of ionizing radiation. This information is given by the inverse dielectric function. Finally, the short time atomistic phenomena caused by ionizing radiation can also be considered to be contained within the dielectric function. During the LDRD, meetings about the work were held every week. These discussions involved theorists, experimentalists and engineers. These discussions branched out into the work done in other projects. For example, the work on EMP effects had influence on another project focused on such phenomena in gases. Furthermore, the physics of radiation detectors and radiation dosimeters was often discussed, and these discussions had impact on related projects. Some LDRD-related documents are now stored on a sharepoint site (https://sharepoint.sandia.gov/sites/LDRD-REMS/default.aspx). In the remainder of this document the work is described in catergories but there is much overlap between the atomistic

  15. Physics of intense, high energy radiation effects

    International Nuclear Information System (INIS)

    Hjalmarson, Harold Paul; Hartman, E. Frederick; Magyar, Rudolph J.; Crozier, Paul Stewart

    2011-01-01

    This document summarizes the work done in our three-year LDRD project titled 'Physics of Intense, High Energy Radiation Effects.' This LDRD is focused on electrical effects of ionizing radiation at high dose-rates. One major thrust throughout the project has been the radiation-induced conductivity (RIC) produced by the ionizing radiation. Another important consideration has been the electrical effect of dose-enhanced radiation. This transient effect can produce an electromagnetic pulse (EMP). The unifying theme of the project has been the dielectric function. This quantity contains much of the physics covered in this project. For example, the work on transient electrical effects in radiation-induced conductivity (RIC) has been a key focus for the work on the EMP effects. This physics in contained in the dielectric function, which can also be expressed as a conductivity. The transient defects created during a radiation event are also contained, in principle. The energy loss lead the hot electrons and holes is given by the stopping power of ionizing radiation. This information is given by the inverse dielectric function. Finally, the short time atomistic phenomena caused by ionizing radiation can also be considered to be contained within the dielectric function. During the LDRD, meetings about the work were held every week. These discussions involved theorists, experimentalists and engineers. These discussions branched out into the work done in other projects. For example, the work on EMP effects had influence on another project focused on such phenomena in gases. Furthermore, the physics of radiation detectors and radiation dosimeters was often discussed, and these discussions had impact on related projects. Some LDRD-related documents are now stored on a sharepoint site (https://sharepoint.sandia.gov/sites/LDRD-REMS/default.aspx). In the remainder of this document the work is described in catergories but there is much overlap between the atomistic calculations, the

  16. Tumor progression: analysis of the instability of the metastatic phenotype, sensitivity to radiation and chemotherapy

    International Nuclear Information System (INIS)

    Welch, D.R.

    1984-01-01

    The major complications for tumor therapy are 1) tumor spread (metastasis); 2) the mixed nature of tumors (heterogeneity); and 3) the capacity of tumors to evolve (progress). To study these tumor characteristics, the rat 13762NF mammary adenocarcinoma was cloned and studied for metastatic properties and sensitivities to therapy (chemotherapy, radiation and hyperthermia). The cell clones were heterogeneous and no correlation between metastatic potential and therapeutic sensitivities was observed. Further, these phenotypes were unstable during pasage in vitro; yet, the changes were clone dependent and reproducible using different cryoprotected cell stocks. To understand the phenotypic instability, subclones were isolated from low and high passage cell clones. The results demonstrated that 1) tumor cells are heterogeneous for multiple phenotypes; 2) tumor cells are unstable for multiple phenotypes; 3) the magnitude, direction and time of occurrence of phenotypic drift is clone dependent; 4) the sensitivity of cell clones to ionizing radiation (γ or heat) and chemotherapy agents is independent of their metastatic potential; 5) shifts in metastatic potential and sensitivity to therapy may occur simultaneously but are not linked; and 6) tumor cells independently diverge to form several subpopulations with unique phenotypic profiles

  17. A survey of cross-section sensitivity analysis as applied to radiation shielding

    International Nuclear Information System (INIS)

    Goldstein, H.

    1977-01-01

    Cross section sensitivity studies revolve around finding the change in the value of an integral quantity, e.g. transmitted dose, for a given change in one of the cross sections. A review is given of the principal methodologies for obtaining the sensitivity profiles-principally direct calculations with altered cross sections, and linear perturbation theory. Some of the varied applications of cross section sensitivity analysis are described, including the practice, of questionable value, of adjusting input cross section data sets so as to provide agreement with integral experiments. Finally, a plea is made for using cross section sensitivity analysis as a powerful tool for analysing the transport mechanisms of particles in radiation shields and for constructing models of how cross section phenomena affect the transport. Cross section sensitivities in the shielding area have proved to be highly problem-dependent. Without the understanding afforded by such models, it is impossible to extrapolate the conclusions of cross section sensitivity analysis beyond the narrow limits of the specific situations examined in detail. Some of the elements that might be of use in developing the qualitative models are presented. (orig.) [de

  18. Radiation monitoring in high energy research facility

    International Nuclear Information System (INIS)

    Miyajima, Mitsuhiro

    1975-01-01

    In High Energy Physics Research Laboratory, construction of high energy proton accelerator is in progress. The accelerator is a cascaded machine comprising Cockcroft type (50 keV), linac (20 MeV), booster synchrotron (500 MeV), and synchrotron (8-12 GeV). Its proton beam intensity is 1x10 13 photons/pulse, and acceleration is carried out at the rate of every 2 minutes. The essential problems of radiation control in high energy accelerators are those of various radiations generated secondarily by proton beam and a number of induced radiations simultaneously originated with such secondary particles. In the Laboratory, controlled areas are divided into color-coded four regions, red, orange, yellow and green, based on each dose-rate. BF 3 counters covered with thick paraffin are used as neutron detectors, and side-window GM tubes, NaI (Tl) scintillators and ionization chambers as γ-detectors. In red region, however, ionization chambers are applied to induced radiation detection, and neutrons are not monitored. NIM standards are adopted for the circuits of all above monitors considering easy maintenance, economy and interchangeability. Notwithstanding the above described systems, these monitors are not sufficient to complete the measurement of whole radiations over wide energy region radiated from the accelerators. Hence separate radiation field measurement is required periodically. An example of the monitoring systems in National Accelerator Laboratory (U.S.) is referred at the last section. (Wakatsuki, Y.)

  19. Highly sensitive detection of a current ripple

    International Nuclear Information System (INIS)

    Aoki, Takashi; Gushiken, Tutomu; Nishikigouri, Kazutaka; Kumada, Masayuki.

    1996-01-01

    In the HIMAC, there are six thyristor-controlled power sources for driving two synchrotrons. These power sources are the three-output terminal power sources which are equipped with positive output, negative output and neutral point for the common mode countermeasures. As electromagnet circuits are connected to the three-output terminal power sources, those are three-line type. In the inside of the power source circuits controlled by thyristors, there is the oscillation peculiar to the power sources, and the variation of voltage induces current spikes. This time, in order to assess the results of the common mode countermeasures in the power source and electromagnet circuits, as one method of cross-check, it is considered that since electromagnet current flows being divided to the bridging resistance and the coil, if attention is paid to the current on bridging resistance side, the ripple components of common mode and normal mode can be detected with high sensitivity, and this was verified. The present state of heightening the performance of synchrotron power sources is explained. The cross-check of the method of assessing the performance of electromagnet power sources is reported. The method of measuring ripple current and the results of the measurement are reported. (K.I.)

  20. Development of high sensitivity radon detectors

    CERN Document Server

    Takeuchi, Y; Kajita, T; Tasaka, S; Hori, H; Nemoto, M; Okazawa, H

    1999-01-01

    High sensitivity detectors for radon in air and in water have been developed. We use electrostatic collection and a PIN photodiode for these detectors. Calibration systems have been also constructed to obtain collection factors. As a result of the calibration study, the absolute humidity dependence of the radon detector for air is clearly observed in the region less than about 1.6 g/m sup 3. The calibration factors of the radon detector for air are 2.2+-0.2 (counts/day)/(mBq/m sup 3) at 0.08 g/m sup 3 and 0.86+-0.06 (counts/day)/(mBq/m sup 3) at 11 g/m sup 3. The calibration factor of the radon detector for water is 3.6+-0.5 (counts/day)/(mBq/m sup 3). The background level of the radon detector for air is 2.4+-1.3 counts/day. As a result, one standard deviation excess of the signal above the background of the radon detector for air should be possible for 1.4 mBq/m sup 3 in a one-day measurement at 0.08 g/m sup 3.

  1. Epidemiological studies in high background radiation areas

    International Nuclear Information System (INIS)

    Akiba, Suminori

    2012-01-01

    Below the doses of 100-200 mSv of radiation exposure, no acute health effect is observed, and the late health effects such as cancer are yet unclear. The problems making the risk evaluation of low dose radiation exposure difficult are the fact that the magnitude of expected health effects are small even if the risk is assumed to increase in proportion to radiation doses. As a result, studies need to be large particular when dealing with rare disease such as cancer. In addition, the expected health effects are so small that they can easily be masked by lifestyles and environmental factors including smoking. This paper will discuss cancer risk possibly associated with low-dose and low-dose rate radiation exposure, describing epidemiological studies on the residents in the high-background radiation areas. (author)

  2. Expression of Ku correlates with radiation sensitivities in the head and neck cancer cell lines

    International Nuclear Information System (INIS)

    Lee, Sang Wook; Yu, Eun Sil; Yi, So Lyoung; Son, Se Hee; Kim, Jong Hoon; Ahn, Seung Do; Shin, Seong Soo; Choi, Eun Kyung

    2004-01-01

    DNA-dependent protein kinase (DNA-PK) is a serine/threonine kinase consisting of a 470 kDa catalytic subunit (DNA-PKcs) and a heterodimeric regulatory complex, called Ku, which is composed of 70 kDa (Ku 70) and 86 kDa (Ku 80) proteins. The DNA-PK has been shown to play a pivotal role in rejoining DNA double-strand-breaks (dsb) in mammalian cells. The purpose of this study is to examine the relationship between the level of Ku expression and radiation sensitivity. Nine head and neck, cancer cell lines showed various intrinsic radiation sensitivities. Among the nine, AMC-HN-3 cell was the most sensitive for X-ray irradiation and AMC-HN-9 cell was the most resistance. The most sensitive and resistant cell lines were selected and the test sensitivity of radiation and expression of Ku were measured. Radiation sensitivity was obtained by colony forming assay and Ku protein expression using Western blot analysis. Ku80 increased expression by radiation, wheras Ku70 did not. Overexpression of Ku80 protein increased radiation resistance in AMC-HN9 cell line. There was a correlation between Ku80 expression and radiation resistance. Ku80 was shown to play an important role in radiation damage response. Induction of Ku80 expression had an important role in DNA damage repair by radiation. Ku80 expression may be an effective predictive assay of radiosensitivity on head and neck cancer

  3. Clinical interest in determinations of cellular radiation sensitivity

    International Nuclear Information System (INIS)

    Suit, H.D.; Baumann, M.; Skates, S.; Convery, K.

    1989-01-01

    This review concludes that there are high expectations that measurements of cell survival in tumor and normal tissues at dose levels employed clinically will yield information of predictive value. Even though the absolute values for SF 2 and its distribution may not be real for the in vivo situation, the measured SF 2 may be of value as a means for ranking sensitivity. In actual clinical practice this would not be expected to be the only predictor employed, but rather one of several prognostic indicators. Hopefully, SF 2 can be developed to be an especially powerful one. There are prospective clinical evaluations of such measurements in progress. Early results are supportive of this approach (Brock et al. 1989a). (author)

  4. Repair of gamma radiation damage in wild type and a radiation sensitive mutant of Deinococcus radiodurans

    International Nuclear Information System (INIS)

    Mizuma, Nagayo

    1989-01-01

    In an effort to examine production and repair of radiation-induced single and double strand breaks in the DNA, a repair-deficient wild type and a repair-deficient mutant, UV17, of Deinococcus radiodurans were subjected to Co-60 gamma irradiation at a dose rate of 6.3 kGy/hr for wild type and 3.9 kGy/hr for UV17 mutant. The shoulder of the curve of UV17 mutant was narrow but existed with the intercept of 0.7 kGy and the corresponding value of the wild type was 4.2 kGy. Mutant cells exhibited about 6 fold increases in sensitivity for the shoulder relative to the wild type. The D 37 doses in the wild type and the mutant were 0.57 kGy and 0.25 kGy, respectively. From the survival curves, difference in the sensitivity between two strains was mainly due to difference of repair capacity than the number of radiation sensitive target. Sedimentation rate of the main component in the irradiated cells of UV17 mutant increased almost to the level of unirradiated control by the postincubation at 30deg C for 3 hrs. The results indicated that this sensitive mutant also exhibited an ability to restore single strand breaks after exposure to a sublethal dose of 0.6 kGy. When restitution of double strand breaks was analyzed by sedimentation in a neutral sucrose gradient, the wild type showed restitution to DNA-membrane complex from large part of the breaks. For UV17 mutant, the apparent increase in DNA-membrane complex formation was seen after 3 hours incubation. Large part of the decrease in the activities of peak 2 was recovered in the peak 1 for the wild type. For the mutant, there was little restitution to peak 1. Almost free DNA component in UV17 mutant, therefore, was merely degraded into shorter pieces. Restoration of DNA-membrane complex from free DNA derived from gamma-ray induced double strand scission involved closely in the repair of gamma-induced damage and survival. (N.K.)

  5. Ionizing radiation sensitivity of DNA polymerase lambda-deficient cells.

    NARCIS (Netherlands)

    Vermeulen, C.; Bertocci, B.; Begg, A.C.; Vens, C.

    2007-01-01

    Ionizing radiation induces a diverse spectrum of DNA lesions, including strand breaks and oxidized bases. In mammalian cells, ionizing radiation-induced lesions are targets of non-homologous end joining, homologous recombination, and base excision repair. In vitro assays show a potential involvement

  6. Radiation Attenuation and Stability of ClearView Radiation Shielding TM-A Transparent Liquid High Radiation Shield.

    Science.gov (United States)

    Bakshi, Jayeesh

    2018-04-01

    Radiation exposure is a limiting factor to work in sensitive environments seen in nuclear power and test reactors, medical isotope production facilities, spent fuel handling, etc. The established choice for high radiation shielding is lead (Pb), which is toxic, heavy, and abidance by RoHS. Concrete, leaded (Pb) bricks are used as construction materials in nuclear facilities, vaults, and hot cells for radioisotope production. Existing transparent shielding such as leaded glass provides minimal shielding attenuation in radiotherapy procedures, which in some cases is not sufficient. To make working in radioactive environments more practicable while resolving the lead (Pb) issue, a transparent, lightweight, liquid, and lead-free high radiation shield-ClearView Radiation Shielding-(Radium Incorporated, 463 Dinwiddie Ave, Waynesboro, VA). was developed. This paper presents the motivation for developing ClearView, characterization of certain aspects of its use and performance, and its specific attenuation testing. Gamma attenuation testing was done using a 1.11 × 10 Bq Co source and ANSI/HPS-N 13.11 standard. Transparency with increasing thickness, time stability of liquid state, measurements of physical properties, and performance in freezing temperatures are reported. This paper also presents a comparison of ClearView with existing radiation shields. Excerpts from LaSalle nuclear power plant are included, giving additional validation. Results demonstrated and strengthened the expected performance of ClearView as a radiation shield. Due to the proprietary nature of the work, some information is withheld.

  7. Antiangiogenic Agent Might Upgrade tumor Cell Sensitivity to Ionizing Radiation

    International Nuclear Information System (INIS)

    Badr, N.M.S.A.

    2013-01-01

    The understanding of the fundamental role of angiogenesis and metastasis in cancer growth has led to tremendous interest in research regarding its regulatory mechanisms and clinical implications in the management of cancer. The present study was conducted to evaluate the influence of the angiogenic regulators modification on the tumor growth and the cell sensitivity to ionizing radiation targeting the improvement of cancer therapeutic protocols. Accordingly, the antiangiogenic activity of apigenin and selenium was tested in vitro via MTT assay. The action of Apigenin and or Selenium was examined in vivo by using a model of solid tumor carcinoma (EAC). The growth rate of solid tumor in all experimental groups was measured by Caliper. The irradiated mice were exposed to 6.5 Gy of gamma rays. Apigenin 50 mg/kg body weight and selenium 5 μg per mice were daily administrated for 14 consecutive days after tumor volume reached 1mm 3 . The angiogenic activators TNF-α (key cytokine) in spleen, serum MMP 2 and MMP 9, liver and tumor NO, the lipid peroxidation (LPx) and angiogenic inhibitor TIMP-1 in spleen as well as, antioxidant markers (CAT, SOD, GPX) in tumor and liver tissue and DNA fragmentation in splenocytes were estimated to monitor efficacy of Apigenin and selenium in cancer treatment strategy. All parameters were determined as a time course on days 16 and 22 after tumor volume reached 1mm 3 . The using of MTT assay on EAC cells shows inhibition in EAC cell proliferation after the incubation with apigenin and /or selenium. The administration of apigenin and /or selenium to mice bearing tumor and to irradiated mice bearing tumor reduce significantly the TNF-α expression, MMP 2,9 , NO , LPx level and increased the antioxidant enzymes (GPx , SOD and CAT) activities. The DNA fragmentation and the antiangiogenic factors TIMP-1 were significantly increased when compared with their values in mice bearing tumor or in irradiated mice bearing tumor. From the results

  8. Radiation cured coatings for high performance products

    International Nuclear Information System (INIS)

    Parkins, J.C.; Teesdale, D.H.

    1984-01-01

    Development over the past ten years of radiation curable coating and lacquer systems and the means of curing them has led to new products in the packaging, flooring, furniture and other industries. Solventless lacquer systems formulated with acrylates and other resins enable high levels of durability, scuff resistance and gloss to be achieved. Ultra violet and electron beam radiation curing are used, the choice depending on the nature of the coating, the product and the scale of the operation. (author)

  9. High energy radiation in cancer treatment

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1959-10-15

    Certain basic recommendations on the use of supervoltage radiation and radioisotope teletherapy in the treatment of malignant growths have been made by an expert study group which met in Vienna in August this y ear. The group, convened jointly by the International Atomic Energy Agency and the World Health Organization, was composed of 20 radiotherapists and radiation physicists from 12 countries. High energy radiation, used in the treatment of malignant tumours, can be either in the form of gamma- or X-rays or in the form of beams of accelerated electrons. The source of radiation is kept at a certain distance from the patient. The study group was agreed on the value of supervoltage radiotherapy, including gamma-ray and high voltage x-ray therapy as well as electron beam therapy. The required gamma radiation can be obtained from large sources of radioactive materials like cobalt 60 or caesium 137, while electron beams are produced by high voltage accelerators. The experts considered the sources in four broad categories: large supervoltage units, intermediate units, small isotope units and units of electron beams or very high energy x-rays. Each group of source was described including its usage. The experts made it clear that while supervoltage radiation should be a part of an organized radiotherapy department, the radiation facilities at any particular establishment should not be of the supervoltage type alone. The high energy facilities could be fruitfully used only when there was a background of general radiotherapy. The group emphasized that supervoltage radiotherapy, in common with other forms of radiotherapy, should be conducted only by adequately trained and qualified personnel, including radiation physicists, and specified the training and qualifications required of such personnel. It was felt that specialized training was one of the main requirements at the present stage and the training programmes of IAEA and WHO should be utilized extensively for this

  10. High energy radiation in cancer treatment

    International Nuclear Information System (INIS)

    1959-01-01

    Certain basic recommendations on the use of supervoltage radiation and radioisotope teletherapy in the treatment of malignant growths have been made by an expert study group which met in Vienna in August this y ear. The group, convened jointly by the International Atomic Energy Agency and the World Health Organization, was composed of 20 radiotherapists and radiation physicists from 12 countries. High energy radiation, used in the treatment of malignant tumours, can be either in the form of gamma- or X-rays or in the form of beams of accelerated electrons. The source of radiation is kept at a certain distance from the patient. The study group was agreed on the value of supervoltage radiotherapy, including gamma-ray and high voltage x-ray therapy as well as electron beam therapy. The required gamma radiation can be obtained from large sources of radioactive materials like cobalt 60 or caesium 137, while electron beams are produced by high voltage accelerators. The experts considered the sources in four broad categories: large supervoltage units, intermediate units, small isotope units and units of electron beams or very high energy x-rays. Each group of source was described including its usage. The experts made it clear that while supervoltage radiation should be a part of an organized radiotherapy department, the radiation facilities at any particular establishment should not be of the supervoltage type alone. The high energy facilities could be fruitfully used only when there was a background of general radiotherapy. The group emphasized that supervoltage radiotherapy, in common with other forms of radiotherapy, should be conducted only by adequately trained and qualified personnel, including radiation physicists, and specified the training and qualifications required of such personnel. It was felt that specialized training was one of the main requirements at the present stage and the training programmes of IAEA and WHO should be utilized extensively for this

  11. Individual radiation sensitivity (gender, age, genetic disposition). Consequences for radiation protection

    International Nuclear Information System (INIS)

    Streffer, C.

    2013-01-01

    The effects of ionising radiation on human health is influenced by a number of physiological and molecular biological factors. This is also valid for the causation of stochastic radiation effects especially the causation of cancer. Several epidemiological studies have resulted with respect to the total rate of solid cancers that women are more sensitive than men by a factor of 1.6 to 2.0. For leukaemia this is not the case. The largest studies come from the investigations on the survivors of the atomic bombs in Hiroshima and Nagasaki. But also studies on the population of the Techa River (Southeast Urals) yield such data. The analyses of single cancer localizations come to different results with respect to the dependence on the sex. Secondary cancers after radiotherapy for cancer treatment show also higher rates in women than in men. A similar situation is observed with respect to the dependence of cancer rate on age. The total rate of solid cancers is highest with children and decreases with increasing age. The effects are very different again with single cancer localizations. An especially strong age dependence was observed for thyroid cancer. Increasingly individuals have been found who are especially radiosensitive on the basis of their genetic disposition also with respect to the causation of cancer. Mechanisms and possibilities to trace these individuals are discussed. It is also discussed whether and to which extent these data should have consequences for the practical radiological protection. (orig.)

  12. The sensitivity of sunflower (Helianthus annuus L. plants to UV-B radiation is altered by nitrogen status

    Directory of Open Access Journals (Sweden)

    Inês Cechin

    2018-02-01

    Full Text Available ABSTRACT: Interaction effects between nitrogen and UV-B radiation were studied in sunflower (Helianthus annuus L. variety IAC-Iarama plants grown in a greenhouse under natural photoperiod conditions. Plants were irradiated with 0.8W m-2 (control or 8.0W m-2 (+UV-B of UV-B radiation for 7h per day. The plants were grown in pots containing vermiculite and watered with 70% of full strength nitrogen-free Long Ashton solution, containing either low (42.3ppm or high (282ppm nitrogen as ammonium nitrate. High nitrogen increased dry matter of stem, leaves and shoot, photosynthetic pigments and photosynthesis (A without any alteration in stomatal conductance (gs nor transpiration (E while it reduced the intercellular CO2 (Ci concentration, and malondialdehyde (MDA content. High UV-B radiation had negative effects on dry matter production, A, gs and E with the effects more marked under high nitrogen, whereas it increased Ci under high nitrogen. Activity of PG-POD was reduced by high UV-B radiation under low nitrogen but it was not changed under high nitrogen. The UV-B radiation increased the MDA content independently of nitrogen level. Results indicate that the effects of UV-B radiation on sunflower plants are dependent of nitrogen supply with high nitrogen making their physiological processes more sensitive to UV-B radiation.

  13. Radiation induced variations in photoperiod-sensitivity, thermo-sensitivity and the number of days to heading in rice

    International Nuclear Information System (INIS)

    Hsieh, S.C.

    1975-01-01

    Radiation induced semi-dwarf mutants derived from five japonica type varieties of rice were studied with regard to their photoperiod-sensitivity, thermo-sensitivity and the number of days to heading. The experiment was carried out under the natural conditions at Taipei. The coefficient of photoperiod-sensitivity and thermo-sensitivity as developed by Oka (1954) were estimated for the mutants in comparison with their original varieties. It was observed that these various physiological characters could be altered easily by mutations. Mutants showed wider ranges in both positive and negative directions than their original varieties in all physiological characters studied. Even though heading date depends on both photoperiod-sensitivity and thermo-sensitivity, it was estimated which of the two contributed more to the induced earliness in each mutant. This offers a basis for selecting early maturing lines of rice

  14. High-intensity xenon plasma discharge lamp for bulk-sensitive high-resolution photoemission spectroscopy.

    Science.gov (United States)

    Souma, S; Sato, T; Takahashi, T; Baltzer, P

    2007-12-01

    We have developed a highly brilliant xenon (Xe) discharge lamp operated by microwave-induced electron cyclotron resonance (ECR) for ultrahigh-resolution bulk-sensitive photoemission spectroscopy (PES). We observed at least eight strong radiation lines from neutral or singly ionized Xe atoms in the energy region of 8.4-10.7 eV. The photon flux of the strongest Xe I resonance line at 8.437 eV is comparable to that of the He Ialpha line (21.218 eV) from the He-ECR discharge lamp. Stable operation for more than 300 h is achieved by efficient air-cooling of a ceramic tube in the resonance cavity. The high bulk sensitivity and high-energy resolution of PES using the Xe lines are demonstrated for some typical materials.

  15. Biological effects of high-energy radiation

    International Nuclear Information System (INIS)

    Curtis, S.B.

    1976-01-01

    The biological effects of high-energy radiation are reviewed, with emphasis on the effects of the hadronic component. Proton and helium ion effects are similar to those of the more conventional and sparsely ionizing x- and γ-radiation. Heavy-ions are known to be more biologically effective, but the long term hazard from accumulated damage has yet to be assessed. Some evidence of widely varying but dramatically increased effectiveness of very high-energy (approximately 70 GeV) hadron beams is reviewed. Finally, the importance of the neutron component in many situations around high-energy accelerators is pointed out

  16. The Pajarito Monitor: a high-sensitivity monitoring system for highly enriched uranium

    International Nuclear Information System (INIS)

    Fehlau, P.E.; Coop, K.; Garcia, C.; Martinez, J.

    1984-01-01

    The Pajarito Monitor for Special Nuclear Material is a high-sensitivity gamma-ray monitoring system for detecting small quantities of highly enriched uranium transported by pedestrians or motor vehicles. The monitor consists of two components: a walk-through personnel monitor and a vehicle monitor. The personnel monitor has a plastic-scintillator detector portal, a microwave occupancy monitor, and a microprocessor control unit that measures the radiation intensity during background and monitoring periods to detect transient diversion signals. The vehicle monitor examines stationary motor vehicles while the vehicle's occupants pass through the personnel portal to exchange their badges. The vehicle monitor has four groups of large plastic scintillators that scan the vehicle from above and below. Its microprocessor control unit measures separate radiation intensities in each detector group. Vehicle occupancy is sensed by a highway traffic detection system. Each monitor's controller is responsible for detecting diversion as well as serving as a calibration and trouble-shooting aid. Diversion signals are detected by a sequential probability ratio hypothesis test that minimizes the monitoring time in the vehicle monitor and adapts itself well to variations in individual passage speed in the personnel monitor. Designed to be highly sensitive to diverted enriched uranium, the monitoring system also exhibits exceptional sensitivity for plutonium

  17. High intensity radiation imaging system

    International Nuclear Information System (INIS)

    Barrett, H.H.

    1976-01-01

    A nuclear imaging system is described for mapping a spatially distributed source of high energy nuclear particles from a living organ which has selectively absorbed a radioactive compound in which the nuclear energy is spatially coded by a zone plate positioned between the source and a spatial detector, and a half tone screen is positioned between the source and the zone plate to increase the definition of the image

  18. Evaluation of the radiation-sensitizer/protector and/or antioxidant efficiencies using Fricke and PAG dosimeters

    International Nuclear Information System (INIS)

    Meesat, Ridthee; Jay-Gerin, Jean-Paul; Khalil, Abdelouahed; Lepage, Martin

    2009-01-01

    In this study, our aim is to assess the potential of Fricke and polyacrylamide gel (PAG) dosimeters to quantitatively evaluate the efficiency of potential radiation sensitizers/protectors and antioxidants. These compounds are of importance in radiotherapy as well as in disease prevention and promotion of health. The basic principle of the Fricke dosimeter is the radiation-induced oxidation of Fe 2+ to Fe 3+ in an aerated aqueous 0.4 M H 2 SO 4 . The production of ferric ions is most sensitive to the radical species produced in the radiolysis of water. Using this method, we observed that cystamine (one of the best of the known radioprotectors) can prevent oxydation of Fe 2+ from reactive radiolysis species. However, one obvious disadvantage of the Fricke dosimeter is that it operates under highly acidic conditions (pH 0.46), which may degrade biological compounds. In contrast, the pH of the polyacrylamide gel (PAG) dosimeter is almost neutral, such that degradation of compounds is less probable. A change in R 2 -dose sensitivity was observed in the presence of radiosensitizers/radioprotectors and antioxidants. The protective effect of Trolox (a well-known antioxidant) and thiourea (a radioprotector) was readily observed using the PAG dosimeter. Incorporation of iodinated radiation sensitizers such as NaI and an iodine contrast agent led to a quantifiable sensitizer enhancement ratio. These studies suggest that the Fricke and the PAG dosimeters have the potential to evaluate the efficiency of radiation sensitizers/protectors and antioxidants.

  19. Radiation sensitivity of tumour cells stained in vitro or in vivo with the bisbenzimide fluorochrome Hoechst 33342

    Energy Technology Data Exchange (ETDEWEB)

    Young, S D; Hill, R P [Ontario Cancer Inst., Toronto, ON (Canada)

    1989-11-01

    The DNA-binding bisbenzimide fluorochrome Hoechst 33342 is being used routinely in radio-biological studies to assess cell kinetic parameters and tumour blood flow. Results indicate that the amount of H33342 accumulated by cells may affect the radiation sensitivity of populations exposed to high concentrations of this fluorochrome, such as those required to achieve stoichiometric binding to DNA. (author).

  20. Sensitivity to plant modelling uncertainties in optimal feedback control of sound radiation from a panel

    DEFF Research Database (Denmark)

    Mørkholt, Jakob

    1997-01-01

    Optimal feedback control of broadband sound radiation from a rectangular baffled panel has been investigated through computer simulations. Special emphasis has been put on the sensitivity of the optimal feedback control to uncertainties in the modelling of the system under control.A model...... in terms of a set of radiation filters modelling the radiation dynamics.Linear quadratic feedback control applied to the panel in order to minimise the radiated sound power has then been simulated. The sensitivity of the model based controller to modelling uncertainties when using feedback from actual...

  1. Intracavity Laser Photoacoustic Spectrometer with High Sensitivity

    International Nuclear Information System (INIS)

    Mitrayana; Muslim; Wasono, M.A.J.

    2002-01-01

    A photo acoustic spectrometer set-up has been upgraded from an extra cavity into an intracavity configuration using a sealed-off CO 2 laser as the spectrometer's radiation source. The detection level of the upgrade Intracavity Photoacoustic Spectrometer (IPS) reached (200 ± 50) ppt for C 2 H 4 and (20 ± 5) ppt for SF 6 with response time (6.6 ± 0.2) s. (author)

  2. Environmental Sensitivity in Children: Development of the Highly Sensitive Child Scale and Identification of Sensitivity Groups

    Science.gov (United States)

    Pluess, Michael; Assary, Elham; Lionetti, Francesca; Lester, Kathryn J.; Krapohl, Eva; Aron, Elaine N.; Aron, Arthur

    2018-01-01

    A large number of studies document that children differ in the degree they are shaped by their developmental context with some being more sensitive to environmental influences than others. Multiple theories suggest that "Environmental Sensitivity" is a common trait predicting the response to negative as well as positive exposures.…

  3. High sensitivity optical measurement of skin gloss

    NARCIS (Netherlands)

    Ezerskaia, A.; Ras, Arno; Bloemen, Pascal; Pereira, S.F.; Urbach, Paul; Varghese, Babu

    2017-01-01

    We demonstrate a low-cost optical method for measuring the gloss properties with improved sensitivity in the low gloss regime, relevant for skin gloss properties. The gloss estimation method is based on, on the one hand, the slope of the intensity gradient in the transition regime between

  4. Compact high-power terahertz radiation source

    Directory of Open Access Journals (Sweden)

    G. A. Krafft

    2004-06-01

    Full Text Available In this paper a new type of THz radiation source, based on recirculating an electron beam through a high gradient superconducting radio frequency cavity, and using this beam to drive a standard electromagnetic undulator on the return leg, is discussed. Because the beam is recirculated and not stored, short bunches may be produced that radiate coherently in the undulator, yielding exceptionally high average THz power for relatively low average beam power. Deceleration from the coherent emission, and the detuning it causes, limits the charge-per-bunch possible in such a device.

  5. Investigation of the modifying effects of vitamin A and hypoxic cell sensitizers in radiation carcinogenesis in mice

    International Nuclear Information System (INIS)

    Mian, T.A.

    1982-01-01

    The effect of vitamin A (retinyl acetate) and three hypoxic cell sensitizers (metronidazole, misonidazole and desmethylmisonidazole) on lung tumor development in strain A mice exposed to radiation was assessed. In experiments involving vitamin A, two groups of mice were fed a low vitamin A diet (< 100 IU/100g diet) while the two other groups were fed a high vitamin A diet (800 IU/100 g diet). After two weeks one group maintained on the high vitamin A diet and one group maintained on the low vitamin A diet were given an acute dose of 500 rad of gamma radiation to the thoracic region. Mice were killed, their lungs were removed and the number of surface adenomas were counted. There was a significant increase in the number of mice bearing lung tumors and the mean number of lung tumors per mouse in the irradiated group maintained on the high vitamin A diet at 40 weeks post irradiation as compared to the irradiated group maintained on a low vitamin A diet. In the other experiment two dose levels of the hypoxic cell sensitizers, 0.2 mg/g and 0.6 mg/g, were used either alone or in combination with 900 rad of gamma radiation in a fractionated dose schedule of twice a week for three weeks. In the groups of mice which received hypoxic cell sensitizers only, the prevalence and the mean number of lung tumors per mouse were somewhat increased in the higher dose group (0.6 mg/g) of misonidazole but was not significantly different from the control animals in the other two sensitizer groups. The combination of hypoxic cell sensitizer and radiation did not show any significant enhancement of lung tumor response when compared with the group which received radiation only. The dose of radiation used in this study significantly enhanced lung tumor formation in mice when compared with the control group

  6. In vivo sensitivity of the embryonic and adult neural stem cell compartments to low-dose radiation.

    Science.gov (United States)

    Barazzuol, Lara; Jeggo, Penny A

    2016-08-01

    The embryonic brain is radiation-sensitive, with cognitive deficits being observed after exposure to low radiation doses. Exposure of neonates to radiation can cause intracranial carcinogenesis. To gain insight into the basis underlying these outcomes, we examined the response of the embryonic, neonatal and adult brain to low-dose radiation, focusing on the neural stem cell compartments. This review summarizes our recent findings. At E13.5-14.5 the embryonic neocortex encompasses rapidly proliferating stem and progenitor cells. Exploiting mice with a hypomorphic mutation in DNA ligase IV (Lig4(Y288C) ), we found a high level of DNA double-strand breaks (DSBs) at E14.5, which we attribute to the rapid proliferation. We observed endogenous apoptosis in Lig4(Y288C) embryos and in WT embryos following exposure to low radiation doses. An examination of DSB levels and apoptosis in adult neural stem cell compartments, the subventricular zone (SVZ) and the subgranular zone (SGZ) revealed low DSB levels in Lig4(Y288C) mice, comparable with the levels in differentiated neuronal tissues. We conclude that the adult SVZ does not incur high levels of DNA breakage, but sensitively activates apoptosis; apoptosis was less sensitively activated in the SGZ, and differentiated neuronal tissues did not activate apoptosis. P5/P15 mice showed intermediate DSB levels, suggesting that DSBs generated in the embryo can be transmitted to neonates and undergo slow repair. Interestingly, this analysis revealed a stage of high endogenous apoptosis in the neonatal SVZ. Collectively, these studies reveal that the adult neural stem cell compartment, like the embryonic counterpart, can sensitively activate apoptosis. © The Author 2016. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

  7. Structural analysis with high brilliance synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ohno, Hideo [Japan Atomic Energy Research Inst., Kamigori, Hyogo (Japan). Kansai Research Establishment

    1997-11-01

    The research subjects in diffraction and scattering of materials with high brilliance synchrotron radiation such as SPring-8 (Super Photon ring 8 GeV) are summarized. The SPring-8 project is going well and 10 public beamlines will be opened for all users in October, 1997. Three JAERI beamlines are also under construction for researches of heavy element science, physical and structural properties under extreme conditions such as high temperature and high pressure. (author)

  8. High sensitivity optical measurement of skin gloss

    OpenAIRE

    Ezerskaia, Anna; Ras, Arno; Bloemen, Pascal; Pereira, Silvania F.; Urbach, H. Paul; Varghese, Babu

    2017-01-01

    We demonstrate a low-cost optical method for measuring the gloss properties with improved sensitivity in the low gloss regime, relevant for skin gloss properties. The gloss estimation method is based on, on the one hand, the slope of the intensity gradient in the transition regime between specular and diffuse reflection and on the other on the sum over the intensities of pixels above threshold, derived from a camera image obtained using unpolarized white light illumination. We demonstrate the...

  9. Phenylbutyrate Sensitizes Human Glioblastoma Cells Lacking Wild-Type P53 Function to Ionizing Radiation

    International Nuclear Information System (INIS)

    Lopez, Carlos A.; Feng, Felix Y.; Herman, Joseph M.; Nyati, Mukesh K.; Lawrence, Theodore S.; Ljungman, Mats

    2007-01-01

    Purpose: Histone deacetylase (HDAC) inhibitors induce growth arrest, differentiation, and apoptosis in cancer cells. Phenylbutyrate (PB) is a HDAC inhibitor used clinically for treatment of urea cycle disorders. Because of its low cytotoxicity, cerebrospinal fluid penetration, and high oral bioavailability, we investigated PB as a potential radiation sensitizer in human glioblastoma cell lines. Methods and Materials: Four glioblastoma cell lines were selected for this study. Phenylbutyrate was used at a concentration of 2 mM, which is achievable in humans. Western blots were used to assess levels of acetylated histone H3 in tumor cells after treatment with PB. Flow cytometry was used for cell cycle analysis. Clonogenic assays were performed to assess the effect of PB on radiation sensitivity. We used shRNA against p53 to study the role of p53 in radiosensitization. Results: Treatment with PB alone resulted in hyperacetylation of histones, confirmed by Western blot analysis. The PB alone resulted in cytostatic effects in three cell lines. There was no evidence of G 1 arrest, increase in sub-G 1 fraction or p21 protein induction. Clonogenic assays showed radiosensitization in two lines harboring p53 mutations, with enhancement ratios (± SE) of 1.5 (± 0.2) and 1.3 (± 0.1), respectively. There was no radiopotentiating effect in two cell lines with wild-type p53, but knockdown of wild-type p53 resulted in radiosensitization by PB. Conclusions: Phenylbutyrate can produce p21-independent cytostasis, and enhances radiation sensitivity in p53 mutant human glioblastoma cells in vitro. This suggests the potential application of combined PB and radiotherapy in glioblastoma harboring mutant p53

  10. High Radiation Resistance IMM Solar Cell

    Science.gov (United States)

    Pan, Noren

    2015-01-01

    Due to high launch costs, weight reduction is a key driver for the development of new solar cell technologies suitable for space applications. This project is developing a unique triple-junction inverted metamorphic multijunction (IMM) technology that enables the manufacture of very lightweight, low-cost InGaAsP-based multijunction solar cells. This IMM technology consists of indium (In) and phosphorous (P) solar cell active materials, which are designed to improve the radiation-resistant properties of the triple-junction solar cell while maintaining high efficiency. The intrinsic radiation hardness of InP materials makes them of great interest for building solar cells suitable for deployment in harsh radiation environments, such as medium Earth orbit and missions to the outer planets. NASA Glenn's recently developed epitaxial lift-off (ELO) process also will be applied to this new structure, which will enable the fabrication of the IMM structure without the substrate.

  11. Sensitivity of an autoradiographic film to ionizing radiation of different types and energies

    International Nuclear Information System (INIS)

    Kras, A.B.; Lutzke-Birk, A.; Kalicki, A.

    1984-01-01

    The ORWO-AF3 autoradiographic film has been studied with regard to its sensitivity to beta radiation (E/sub max/ = 0.155 and 0.306 MeV, resp.), gamma radiation of more than 1 MeV and K/sub α/ and K/sub β/ radiation of about 5.9 KeV. The obtained data can be used for the correction of depth distribution profiles if elements are labelled with radioisotopes emitting mixed radiation, e.g., beta and gamma radiation

  12. Charge-coupled devices as positron sensitive detectors of x-radiation

    International Nuclear Information System (INIS)

    Volkov, G.S.; Zazhivikhin, V.V.; Zajtsev, V.I.; Mishevskij, V.O.

    1996-01-01

    Results of theoretical and experimental studies on the sensitivity and spatial resolution of devices with a charge link (CLD) within the X-radiation energy range are described. The areas of the device application are considered

  13. Emulsion polymerization with high energy radiation

    International Nuclear Information System (INIS)

    Stannett, V.T.; Stahel, E.P.

    1992-01-01

    High energy radiation, particularly that of cobalt-60 or caesium-137 gamma-rays, provides in principle an ideal initiator for emulsion polymerization. The high free radical yields from the radiolysis of the aqueous phase combined with the high kinetic chain lengths associated with emulsion polymerization lead to a highly effective utilization of the radiation. There are other important advantages compared with the use of chemical initiators such as potassium persulfate. These are outlined in the chapter, together with some attendant disadvantages. Radiation-induced initiation is temperature independent, and low temperature polymerizations can be conducted with ease. Monomers that mainly terminate their growing chains by chain transfer to monomer give higher molecular weights at lower temperatures. Industrially, vinyl acetate is an important example of such a monomer, and it has been studied using radiation initiation. Both laboratory and pilot plant studies have been carried out and reported. The results are summarized in this chapter. Styrene is the classical example of a material that under a number of conditions closely obeys the so-called ideal Smith-Ewart kinetics. It has been found that under similar conditions but substituting radiation for potassium persulfate as the initiator, ideal kinetics were closely followed. Most of the conventional and some non-standard vinyl and diene monomers have been studied to some extent with radiation-initiated polymerizations in emulsion. To conserve space however, this chapter presents and discusses the results obtained only with styrene and vinyl acetate, both in laboratory and pilot plant investigations. Other monomers and special situations are referenced either directly or to the other available reviews. (orig.)

  14. Radiation sensitivity and EPR dosimetric potential of gallic acid and its esters

    International Nuclear Information System (INIS)

    Tuner, Hasan; Oktay Bal, M.; Polat, Mustafa

    2015-01-01

    In the preset work the radiation sensitivities of Gallic Acid anhydrous and monohydrate, Octyl, Lauryl, and Ethyl Gallate (GA, GAm, OG, LG, and EG) were investigated in the intermediate (0.5–20 kGy) and low radiation (<10 Gy) dose range using Electron Paramagnetic Resonance (EPR) spectroscopy. While OG, LG, and EG are presented a singlet EPR spectra, their radiation sensitivity found to be very different in the intermediate dose range. At low radiation dose range (<10 Gy) only LG is found to be present a signal that easily distinguished from the noise signals. The intermediate and low dose range radiation sensitivities are compared using well known EPR dosimeter alanine. The radiation yields (G) of the interested material were found to be 1.34×10 −2 , 1.48×10 −2 , 4.14×10 −2 , and 6.03×10 −2 , 9.44×10 −2 for EG, GA, GAm, OG, and LG, respectively at the intermediate dose range. It is found that the simple EPR spectra and the noticeable EPR signal of LG make it a promising dosimetric material to be used below 10 Gy of radiation dose. - Highlights: • Radiation sensitivity of gallic acid and its esters were studied in intermediate and low radiation dose range using EPR. • While the irradiated samples of GA were presented complex EPR spectra the esters presented singlet ESR spectra. • Samples were compared to alanine in terms of the dosimetric point of view. • The radiation sensitivities of the investigated materials were very low at intermediate doses. • Lauryl ester of gallic acid was found to present a good sensitivity below 10 Gy

  15. The sensitivity of active and inactive chromatin to ionizing radiation-induced DNA strand breakage

    International Nuclear Information System (INIS)

    Chiu, S.-M.; Oleinick, N.L.

    1982-01-01

    The sensitivity of DNA in actively transcribing and inactive states has been compared with regard to γ-radiation-induced single-strand break (SSB) induction. The results indicate that chromatin organization is important in the determination of the sensitivity of cellular DNA toward γ-radiation: Not only the yield but also the rate of repair of SSB is greater in the actively transcribing genes than in the total nuclear DNA. (author)

  16. Monsoon sensitivity to aerosol direct radiative forcing in the ...

    Indian Academy of Sciences (India)

    to the total, scattering aerosols and black carbon aerosols. ... acts as an internal damping mechanism spinning down the regional hydrological cycle and leading to sig- ... tion and emission of longwave radiation. ... effect of aerosols over India, where the emission of .... that aerosol effects on monsoon water cycle dynam-.

  17. Chemical protection and sensitization to ionizing radiation:molecular investigations

    International Nuclear Information System (INIS)

    Badiello, R.

    1980-01-01

    Chemical radioprotection and radiosensitization are induced by the presence of certain chemical compounds, which reduce or enhance the effect of ionizing radiation on living organisms. Such substances are either naturally present or may be artificially introduced in the living cells. Chemical radioprotectors are interesting for possible application in the health protection of both professionally exposed workers and patients treated by radiation for diagnostic and thereapeutic purposes. Interest in chemical radiosensitization has increased recently because of its potential application in the radiotherapy of tumours. Both radioprotection and radiosensitization occur by means of complicated mechanisms, which at first correspond to very fast reactions. The mechanism of the interaction between such substances and radiation-induced biological radicals has been investigated by means of pulse radiolysis and rapid mixing techniques. Examples of the application of these techniques are given to illustrate how information has been obtained on the molecular basis of radiation chemical modi-fication at the cellular level. In particular some interactions between model systems of biological interest (DNA, DNA components, enzymes, amino acids, etc.) and sulphur-containing radioprotectors (glutathione, cysteine, etc.) and/or electroaffinic radiosensitizers, are described. (H.K.)

  18. High pressure and synchrotron radiation satellite workshop

    Energy Technology Data Exchange (ETDEWEB)

    Bass, J.; Guignot, N.; Morard, G.; Mezouar, M.; Andrault, D.; Bolfan-Casanova, N.; Sturhahn, W.; Daniel, I.; Reynard, B.; Simionovici, A.; Sanchez Valle, C.; Martinez, I.; Kantor, I.; Dubrovinsky, I.; Mccammon, C.; Dubrovinskaia, N.; Kurnosiv, A.; Kuznetsov, A.; Goncharenko, I.; Loubeyre, P.; Desgreniers, S.; Weck, G.; Yoo, C.S.; Iota, V.; Park, J.; Cynn, H.; Gorelli, F.; Toulemonde, P.; Machon, D.; Merlen, A.; San Miguel, A.; Amboage, M.; Aquilanti, G.; Mathon, O.; Pascarelli, S.; Itie, J.P.; Mcmillan, P.F.; Trapananti, A.; Di Cicco, A.; Panfilis, S. de; Filipponi, A.; Kreisel, J.; Bouvier, P.; Dkhil, B.; Chaabane, B.; Rosner, H.; Koudela, D.; Schwarz, U.; Handestein, A.; Hanfland, M.; Opahle, I.; Koepernik, K.; Kuzmin, M.; Mueller, K.H.; Mydosh, J.; Richter, M.; Hejny, C.; Falconi, S.; Lundegaard, L.F.; Mcmahon, M.I; Loa, I.; Syassen, K.; Wang, X.; Roth, H.; Lorenz, T.; Farber Daniel, I.; Antonangeli Daniele, I.; Krisch, M.; Badro, J.; Fiquet, G.; Occelli, F.; Mao, W.L.; Mao, H.K.; Eng, P.; Kao, C.C.; Shu, J.F.; Hemley, R.J.; Tse, J.S.; Yao, Y.; Deen, P.P.; Paolasini, I.; Braithwaite, D.; Kernavanois, N.; Lapertot, G.; Rupprecht, K.; Leupold, O.; Ponkratz, U.; Wortmann, G.; Beraud, A.; Krisch, M.; Farber, D.; Antonangeli, D.; Aracne, C.; Zarestky, J.L.; Mcqueeney, R.; Mathon, O.; Baudelet, F.; Decremps, F.; Itie, J.P.; Nataf, I.; Pascarelli, S.; Polian, A

    2006-07-01

    The workshop is dedicated to recent advances on science at high pressure at third generation synchrotron sources. A variety of experiments using synchrotron radiation techniques including X-ray diffraction, EXAFS (extended X-ray absorption fine structure), inelastic X-ray scattering, Compton scattering and Moessbauer spectroscopy of crystalline, liquid or amorphous samples, are reported. This document gathers the abstracts of the presentations.

  19. High pressure and synchrotron radiation satellite workshop

    International Nuclear Information System (INIS)

    Bass, J.; Guignot, N.; Morard, G.; Mezouar, M.; Andrault, D.; Bolfan-Casanova, N.; Sturhahn, W.; Daniel, I.; Reynard, B.; Simionovici, A.; Sanchez Valle, C.; Martinez, I.; Kantor, I.; Dubrovinsky, I.; Mccammon, C.; Dubrovinskaia, N.; Kurnosiv, A.; Kuznetsov, A.; Goncharenko, I.; Loubeyre, P.; Desgreniers, S.; Weck, G.; Yoo, C.S.; Iota, V.; Park, J.; Cynn, H.; Gorelli, F.; Toulemonde, P.; Machon, D.; Merlen, A.; San Miguel, A.; Amboage, M.; Aquilanti, G.; Mathon, O.; Pascarelli, S.; Itie, J.P.; Mcmillan, P.F.; Trapananti, A.; Di Cicco, A.; Panfilis, S. de; Filipponi, A.; Kreisel, J.; Bouvier, P.; Dkhil, B.; Chaabane, B.; Rosner, H.; Koudela, D.; Schwarz, U.; Handestein, A.; Hanfland, M.; Opahle, I.; Koepernik, K.; Kuzmin, M.; Mueller, K.H.; Mydosh, J.; Richter, M.; Hejny, C.; Falconi, S.; Lundegaard, L.F.; Mcmahon, M.I; Loa, I.; Syassen, K.; Wang, X.; Roth, H.; Lorenz, T.; Farber Daniel, I.; Antonangeli Daniele, I.; Krisch, M.; Badro, J.; Fiquet, G.; Occelli, F.; Mao, W.L.; Mao, H.K.; Eng, P.; Kao, C.C.; Shu, J.F.; Hemley, R.J.; Tse, J.S.; Yao, Y.; Deen, P.P.; Paolasini, I.; Braithwaite, D.; Kernavanois, N.; Lapertot, G.; Rupprecht, K.; Leupold, O.; Ponkratz, U.; Wortmann, G.; Beraud, A.; Krisch, M.; Farber, D.; Antonangeli, D.; Aracne, C.; Zarestky, J.L.; Mcqueeney, R.; Mathon, O.; Baudelet, F.; Decremps, F.; Itie, J.P.; Nataf, I.; Pascarelli, S.; Polian, A.

    2006-01-01

    The workshop is dedicated to recent advances on science at high pressure at third generation synchrotron sources. A variety of experiments using synchrotron radiation techniques including X-ray diffraction, EXAFS (extended X-ray absorption fine structure), inelastic X-ray scattering, Compton scattering and Moessbauer spectroscopy of crystalline, liquid or amorphous samples, are reported. This document gathers the abstracts of the presentations

  20. Characterization of new radiation-sensitive mutant, Escherichia coli K-12 radC102

    International Nuclear Information System (INIS)

    Felzenszwalb, I.; Sargentini, N.J.; Smith, K.C.

    1984-01-01

    A new radiation-sensitive mutant, radC, has been isolated. The radC gene is located at 81.0 min on the Escherichia coli K-12 linkage map. The radC mutation sensitized cells to uv radiation, but unlike most DNA repair mutations, sensitization to X rays was observed only for rich medium-grown cells. For cells grown in rich medium, the radC mutant was normal for γ radiation mutagenesis, but showed less uv-radiation mutagenesis than the wild-type strain; it showed normal amount of X- and uv-radiation-induced DNA degradation, and it wasapprox. =60% deficient in recombination ability. The radC strain was normal for host cell reactivation of γ and uv-irradiated bacteriophage the radC mutation did not sensitize a recA strain, but did sensitize a radA and a polA strain to X and uv radiation and a uvrA strain to uv radiation. Therefore, it is suggested that the radC gene product plays a role in the growth medium-dependent, recA gene-dependent repair of DNA single-strand breaks after X irradiation, and in postreplication repair after uv irradiation

  1. Sensitive Detection: Photoacoustics, Thermography, and Optical Radiation Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Diebold, Gerald J. [Brown Univ., Providence, RI (United States)

    2017-04-21

    Research during the granting period has been carried out in several areas concerned with sensitive detection. An infrared pyrometer based on the photoacoustic effect has been developed. The sensitivity of this instrument to temperature differentials has been shown to be 50 mK. An investigation of transients that accompany photoacoustic waves generated by pulsed lasers has been carried out. Experiments have shown the existence of the transients, and a theory based on rapid heat diffusion has been developed. The photoacoustic effect in one dimension is known to increase without bound (in the linear acoustics regime) when an optical beam moves in a fluid at the sound speed. A solution to the wave equation for pressure has been found that describes the photoacoustic effect in a cell where an infrared optical grating moves at the sound speed. It was shown that the amplification effect exists along with a cavity resonance that can be used to great advantage in trace gas detection. The theory of the photoacoustic effect in a structure where the acoustic properties periodically vary in a one-dimensional based has been formulated based on solutions to a Mathieu equation. It was found that it is possible to excite photoacoustic waves within the band gaps to produce large amplitude acoustic waves. The idea of self-oscillation in a photoacoustic cell using a continuous laser has been investigated. A theory has been completed showing that in a compressive wave, the absorption increases as a result of the density increase leading to further absorption and hence an increased amplitude photoacoustic effect with the result that in a resonator, self-oscillation can place. Experiments have been carried out where irradiation of a suspension of absorbing carbon particles with a high power laser has been shown to result in cavitation luminescence. That is, following generation of CO and H2 from the carbon particles through the carbon-steam reaction, an expanding gas bubble is

  2. A systemic administration of liposomal curcumin inhibits radiation pneumonitis and sensitizes lung carcinoma to radiation

    Directory of Open Access Journals (Sweden)

    Shi HS

    2012-05-01

    Full Text Available Hua-shan Shi1,* Xiang Gao,1,3,* Dan Li,1,* Qiong-wen Zhang,1 Yong-sheng Wang,2 Yu Zheng,1 Lu-Lu Cai,1 Ren-ming Zhong,2 Ao Rui,1 Zhi-yong Li,1 Hao Zheng,1 Xian-cheng Chen,1 Li-juan Chen,11State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medicine School, Sichuan University, Chengdu, Sichuan, People's Republic of China; 2State Key Laboratory of Biotherapy and Department of Thoracic Oncology, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, People's Republic of China; 3Deparment of Pathophysiology, College of Preclinical and Forensic Medical Sciences, Sichuan University, Chengdu, People's Republic of China*These authors contributed equally to this workAbstract: Radiation pneumonitis (RP is an important dose-limiting toxicity during thoracic radiotherapy. Previous investigations have shown that curcumin is used for the treatment of inflammatory conditions and cancer, suggesting that curcumin may prevent RP and sensitize cancer cells to irradiation. However, the clinical advancement of curcumin is limited by its poor water solubility and low bioavailability after oral administration. Here, a water-soluble liposomal curcumin system was developed to investigate its prevention and sensitizing effects by an intravenous administration manner in mice models. The results showed that liposomal curcumin inhibited nuclear factor-κB pathway and downregulated inflammatory factors including tumor necrosis factor-α, interleukin (IL-6, IL-8, and transforming growth factor-β induced by thoracic irradiation. Furthermore, the combined treatment with liposomal curcumin and radiotherapy increased intratumoral apoptosis and microvessel responses to irradiation in vivo. The significantly enhanced inhibition of tumor growth also was observed in a murine lung carcinoma (LL/2 model. There were no obvious toxicities observed in mice. The current results indicate that liposomal curcumin can effectively

  3. High sensitivity optical measurement of skin gloss.

    Science.gov (United States)

    Ezerskaia, Anna; Ras, Arno; Bloemen, Pascal; Pereira, Silvania F; Urbach, H Paul; Varghese, Babu

    2017-09-01

    We demonstrate a low-cost optical method for measuring the gloss properties with improved sensitivity in the low gloss regime, relevant for skin gloss properties. The gloss estimation method is based on, on the one hand, the slope of the intensity gradient in the transition regime between specular and diffuse reflection and on the other on the sum over the intensities of pixels above threshold, derived from a camera image obtained using unpolarized white light illumination. We demonstrate the improved sensitivity of the two proposed methods using Monte Carlo simulations and experiments performed on ISO gloss calibration standards with an optical prototype. The performance and linearity of the method was compared with different professional gloss measurement devices based on the ratio of specular to diffuse intensity. We demonstrate the feasibility for in-vivo skin gloss measurements by quantifying the temporal evolution of skin gloss after application of standard paraffin cream bases on skin. The presented method opens new possibilities in the fields of cosmetology and dermatopharmacology for measuring the skin gloss and resorption kinetics and the pharmacodynamics of various external agents.

  4. Progress in high-dose radiation dosimetry

    International Nuclear Information System (INIS)

    Ettinger, K.V.; Nam, J.W.; McLaughlin, W.L.; Chadwick, K.H.

    1981-01-01

    The last decade has witnessed a deluge of new high-dose dosimetry techniques and expanded applications of methods developed earlier. Many of the principal systems are calibrated by means of calorimetry, although production of heat is not always the final radiation effect of interest. Reference systems also include a number of chemical dose meters: ferrous sulphate, ferrous-cupric sulphate, and ceric sulphate acidic aqueous solutions. Requirements for stable and reliable transfer dose meters have led to further developments of several important high-dose systems: amino acids and saccharides analysed by ESR or lyoluminescence, thermoluminescent materials, radiochromic dyes and plastics, ceric-cerous solutions analysed by potentiometry, and ethanol-chlorobenzene solutions analysed by high-frequency oscillometry. A number of other prospective dose meters are also treated in this review. In addition, an IAEA programme of high-dose standardization and intercomparison for industrial radiation processing is described. (author)

  5. Ion exchange resins as high-dose radiation dosimeters

    International Nuclear Information System (INIS)

    Alian, A.; Dessouki, A.; El-Assay, N.B.

    1984-01-01

    This paper reports on the possibility of using various types of ion exchange resins as high-dose radiation dosimeters, by analysis of the decrease in exchange capacity with absorbed dose. The resins studied are Sojuzchim-export-Moscow Cation Exchanger KU-2 and Anion Exchanger AV-17 and Merck Cation Exchanger I, and Merck Anion Exchangers II and III. Over the dose range 1 to 100 kGy, the systems show linearity between log absorbed dose and decrease in resin ion exchange capacity. The slope of this response function differs for the different resins, depending on their ionic form and degree of cross-linking. The radiation sensitivity increases in the order KU-2; Exchanger I; AV-17; Exchanger II; Exchanger III. Merck resins with moisture content of 21% showed considerably higher radiation sensitivity than those with 2 to 3% moisture content. The mechanism of radiation-induced denaturing of the ion exchanger resins involves cleavage and decomposition of functional substituents, with crosslinking playing a stabilizing role, with water and its radiolytic products serving to inhibit radical recombination and interfering with the protection cage effect of crosslinking. (author)

  6. Ultra Secure High Reliability Wireless Radiation Monitor

    International Nuclear Information System (INIS)

    Cordaro, J.; Shull, D.; Farrar, M.; Reeves, G.

    2011-01-01

    Radiation monitoring in nuclear facilities is essential to safe operation of the equipment as well as protecting personnel. In specific, typical air monitoring of radioactive gases or particulate involves complex systems of valves, pumps, piping and electronics. The challenge is to measure a representative sample in areas that are radioactively contaminated. Running cables and piping to these locations is very expensive due to the containment requirements. Penetration into and out of an airborne or containment area is complex and costly. The process rooms are built with thick rebar-enforced concrete walls with glove box containment chambers inside. Figure 1 shows high temperature radiation resistance cabling entering the top of a typical glove box. In some case, the entire processing area must be contained in a 'hot cell' where the only access into the chamber is via manipulators. An example is shown in Figure 2. A short range wireless network provides an ideal communication link for transmitting the data from the radiation sensor to a 'clean area', or area absent of any radiation fields or radioactive contamination. Radiation monitoring systems that protect personnel and equipment must meet stringent codes and standards due to the consequences of failure. At first glance a wired system would seem more desirable. Concerns with wireless communication include latency, jamming, spoofing, man in the middle attacks, and hacking. The Department of Energy's Savannah River National Laboratory (SRNL) has developed a prototype wireless radiation air monitoring system that address many of the concerns with wireless and allows quick deployment in radiation and contamination areas. It is stand alone and only requires a standard 120 VAC, 60 Hz power source. It is designed to be mounted or portable. The wireless link uses a National Security Agency (NSA) Suite B compliant wireless network from Fortress Technologies that is considered robust enough to be used for classified data

  7. ULTRA SECURE HIGH RELIABILITY WIRELESS RADIATION MONITOR

    Energy Technology Data Exchange (ETDEWEB)

    Cordaro, J.; Shull, D.; Farrar, M.; Reeves, G.

    2011-08-03

    Radiation monitoring in nuclear facilities is essential to safe operation of the equipment as well as protecting personnel. In specific, typical air monitoring of radioactive gases or particulate involves complex systems of valves, pumps, piping and electronics. The challenge is to measure a representative sample in areas that are radioactively contaminated. Running cables and piping to these locations is very expensive due to the containment requirements. Penetration into and out of an airborne or containment area is complex and costly. The process rooms are built with thick rebar-enforced concrete walls with glove box containment chambers inside. Figure 1 shows high temperature radiation resistance cabling entering the top of a typical glove box. In some case, the entire processing area must be contained in a 'hot cell' where the only access into the chamber is via manipulators. An example is shown in Figure 2. A short range wireless network provides an ideal communication link for transmitting the data from the radiation sensor to a 'clean area', or area absent of any radiation fields or radioactive contamination. Radiation monitoring systems that protect personnel and equipment must meet stringent codes and standards due to the consequences of failure. At first glance a wired system would seem more desirable. Concerns with wireless communication include latency, jamming, spoofing, man in the middle attacks, and hacking. The Department of Energy's Savannah River National Laboratory (SRNL) has developed a prototype wireless radiation air monitoring system that address many of the concerns with wireless and allows quick deployment in radiation and contamination areas. It is stand alone and only requires a standard 120 VAC, 60 Hz power source. It is designed to be mounted or portable. The wireless link uses a National Security Agency (NSA) Suite B compliant wireless network from Fortress Technologies that is considered robust enough to be

  8. Semiconductor high-energy radiation scintillation detector

    International Nuclear Information System (INIS)

    Kastalsky, A.; Luryi, S.; Spivak, B.

    2006-01-01

    We propose a new scintillation-type detector in which high-energy radiation generates electron-hole pairs in a direct-gap semiconductor material that subsequently recombine producing infrared light to be registered by a photo-detector. The key issue is how to make the semiconductor essentially transparent to its own infrared light, so that photons generated deep inside the semiconductor could reach its surface without tangible attenuation. We discuss two ways to accomplish this, one based on doping the semiconductor with shallow impurities of one polarity type, preferably donors, the other by heterostructure bandgap engineering. The proposed semiconductor scintillator combines the best properties of currently existing radiation detectors and can be used for both simple radiation monitoring, like a Geiger counter, and for high-resolution spectrography of the high-energy radiation. An important advantage of the proposed detector is its fast response time, about 1 ns, essentially limited only by the recombination time of minority carriers. Notably, the fast response comes without any degradation in brightness. When the scintillator is implemented in a qualified semiconductor material (such as InP or GaAs), the photo-detector and associated circuits can be epitaxially integrated on the scintillator slab and the structure can be stacked-up to achieve virtually any desired absorption capability

  9. Andrographolide Sensitizes Ras-Transformed Cells to Radiation in vitro and in vivo

    International Nuclear Information System (INIS)

    Hung, Shih-Kai; Hung, Ling-Chien; Kuo, Cheng-Deng

    2010-01-01

    Purpose: Increasing the sensitivity of tumor cells to radiation is a major goal of radiotherapy. The present study investigated the radiosensitizing effects of andrographolide and examined the molecular mechanisms of andrographolide-mediated radiosensitization. Methods and Materials: An H-ras-transformed rat kidney epithelial (RK3E) cell line was used to measure the radiosensitizing effects of andrographolide in clonogenic assays, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide assays, and a xenograft tumor growth model. The mechanism of andrographolide-sensitized cell death was analyzed using annexin V staining, caspase 3 activity assays, and terminal transferase uridyl nick end labeling assays. The roles of nuclear factor kappa B (NF-κB) and Akt in andrographolide-mediated sensitization were examined using reporter assays, electrophoretic mobility shift assays, and Western blotting. Results: Concurrent andrographolide treatment (10 μM, 3 h) sensitized Ras-transformed cells to radiation in vitro (sensitizer enhancement ratio, 1.73). Andrographolide plus radiation (one dose of 300 mg/kg peritumor andrographolide and one dose of 6 Gy radiation) resulted in significant tumor growth delay (27 ± 2.5 days) compared with radiation alone (22 ± 1.5 days; p <.05). Radiation induced apoptotic markers (e.g., caspase-3, membrane reversion, DNA fragmentation), and andrographolide treatment did not promote radiation-induced apoptosis. However, the protein level of activated Akt was significantly reduced by andrographolide. NF-κB activity was elevated in irradiated Ras-transformed cells, and andrographolide treatment significantly reduced radiation-induced NF-κB activity. Conclusion: Andrographolide sensitized Ras-transformed cells to radiation both in vitro and in vivo. Andrographolide-mediated radiosensitization was associated with downregulation of Akt and NF-κB activity. These observations indicate that andrographolide is a novel radiosensitizing agent

  10. Effects of chemical sensitizers on gamma radiation processing of ...

    African Journals Online (AJOL)

    The potential of gamma radiation processing in cross-linking natural rubber latex (NRL) for production of dipped goods has been studied. NRL produced in Ghana was irradiated to 10, 20, 30, 40 and 50 kGy, respectively, in a Gamma Chamber of dose rate 0.65 kGy/h. Irradiation of the NRL was also carried out in the ...

  11. A high resolution position sensitive X-ray MWPC for small angle X-ray diffraction

    International Nuclear Information System (INIS)

    Bateman, J.E.; Connolly, J.F.; Stephenson, R.; Tappern, G.J.

    1981-02-01

    A small sealed-off delay line readout MWPC X-ray detector has been designed and built for small angle X-ray diffraction applications. Featuring a sensitive area of 100 mm x 25 mm it yields a spatial resolution of 0.13 mm (standard deviation) with a high rate capability and good quantum efficiency for copper K radiation. (author)

  12. Construction and isolation of radiation sensitive mutants of Escherichia Coli

    International Nuclear Information System (INIS)

    Cuapio P, P.

    1995-01-01

    Damage to DNA by ionizing radiation consists mainly of single (SSB) and double (DSB) strand breaks as well as several types of base alterations, all of which may be removed by different repair mechanisms. Radiation also induces the SOS response, a set of repair and/or damage tolerance genes involved in functions such as replication arrest, excision and recombination repair, increase of both spontaneous and induced mutation and prophage induction, among others. The degree of SOS induction is related to the type and amount of damage and may be easily determined by a simple colorimetric assay, the SOS chromo test. In order to investigate the role of protection and/or repair genes on bacterial radiosensitivity, E. coli strains defective in either oxyR, recJ or recO genes were constructed and their respective SOS response to radiation, duly examined. The results show that although lack of regulatory gene oxyR increases radiosensitivity, it is the deficiencies in recJ and recO which seem to be more important. Both genes appear to take part in the repair of DSB and according to SOS measurements, their role is related also to damage processing conducent to the SOS triggering signal. A hypothetical working mechanism for the purpose, partially supported by the data is proposed. (Author)

  13. The selectively bred high alcohol sensitivity (HAS) and low alcohol sensitivity (LAS) rats differ in sensitivity to nicotine.

    Science.gov (United States)

    de Fiebre, NancyEllen C; Dawson, Ralph; de Fiebre, Christopher M

    2002-06-01

    Studies in rodents selectively bred to differ in alcohol sensitivity have suggested that nicotine and ethanol sensitivities may cosegregate during selective breeding. This suggests that ethanol and nicotine sensitivities may in part be genetically correlated. Male and female high alcohol sensitivity (HAS), control alcohol sensitivity, and low alcohol sensitivity (LAS) rats were tested for nicotine-induced alterations in locomotor activity, body temperature, and seizure activity. Plasma and brain levels of nicotine and its primary metabolite, cotinine, were measured in these animals, as was the binding of [3H]cytisine, [3H]epibatidine, and [125I]alpha-bungarotoxin in eight brain regions. Both replicate HAS lines were more sensitive to nicotine-induced locomotor activity depression than the replicate LAS lines. No consistent HAS/LAS differences were seen on other measures of nicotine sensitivity; however, females were more susceptible to nicotine-induced seizures than males. No HAS/LAS differences in nicotine or cotinine levels were seen, nor were differences seen in the binding of nicotinic ligands. Females had higher levels of plasma cotinine and brain nicotine than males but had lower brain cotinine levels than males. Sensitivity to a specific action of nicotine cosegregates during selective breeding for differential sensitivity to a specific action of ethanol. The differential sensitivity of the HAS/LAS rats is due to differences in central nervous system sensitivity and not to pharmacokinetic differences. The differential central nervous system sensitivity cannot be explained by differences in the numbers of nicotinic receptors labeled in ligand-binding experiments. The apparent genetic correlation between ethanol and nicotine sensitivities suggests that common genes modulate, in part, the actions of both ethanol and nicotine and may explain the frequent coabuse of these agents.

  14. Sensitivity of the vibrios to ultraviolet-radiation

    International Nuclear Information System (INIS)

    Banerjee, S.K.; Chatterjee, S.N.

    1977-01-01

    The ultraviolet-inactivation kinetics of a number of strains of Vibrio cholerae (classical), Vibrio cholerae (el tor), NAG vibrios and Vibrio parahaemolyticus were investigated. Statistical analyses revealed significant differences between any two of the four types of vibrio in respect of their sensitivity to U.V. (author)

  15. Sensitivity of Escherichia coli acrA Mutants to Psoralen plus Near-Ultraviolet Radiation

    DEFF Research Database (Denmark)

    Hansen, M. Trier

    1982-01-01

    The sensitivity to psoralen plus near-ultraviolet radiation (PUVA) was compared in a pair of E. coli strains differing at the acrA locus. Survival was determined for both bacteria and phage λ. AcrA mutant cells were 40 times more sensitive than wild type to the lethal effect of PUVA. Free λ phage...

  16. Status of multigroup sensitivity profiles and covariance matrices available from the radiation shielding information center

    International Nuclear Information System (INIS)

    Roussin, R.W.; Drischler, J.D.; Marable, J.H.

    1980-01-01

    In recent years multigroup sensitivity profiles and covariance matrices have been added to the Radiation Shielding Information Center's Data Library Collection (DLC). Sensitivity profiles are available in a single package. DLC-45/SENPRO, and covariance matrices are found in two packages, DLC-44/COVERX and DLC-77/COVERV. The contents of these packages are described and their availability is discussed

  17. Studies on radiation-sensitive nonsilver halide materials, (2)

    International Nuclear Information System (INIS)

    Komizu, Hideo; Honda, Koichi; Yabe, Akira; Kawasaki, Masami; Yamanaka, Takeshi.

    1980-01-01

    Dye-precursors made from furfural and some aniline derivatives become red-colored upon irradiation with ionization radiatios in PVC matrix, forming Stenhouse salts with the HCl evolved from the matrix. The coloration of the precursor from N-methylaniline, having the most excellent potential for dosimetry among the precursors, was studied for the irradiation of electron beam (60 kV) and X-ray (50 - 240 kVp). The following conclusions were obtained for the electron beam bombardment. (1) The response range is 10 -8 - 10 -6 C/cm 2 or 10 3 - 10 5 rad, where good linearity between coloration and charge density exists. (2) The highest sensitivity is obtained when the concentration of the precursor is >=5 wt% for the amount of PVC and the film thickness is >=32 μm. (3) Addition of 25 wt% of DOP enhances not only the sensitivity by ca. 20% but also the stability of the color from several days to several months. (4) The sensitivity is increased by ca. 15% when a conductive base is used for the film. (5) G value for the formation of the dye, i.e., that for the formation of HCl is 13.5 - 15.5. The followings were obtained for the irradiation of X-ray. (1) The response range is 10 3 - 10 5 R or rad. (2) The sensitivity for the absorbed dose is independent of the energy but is approximately proportional to the film thickness. (3) The sensitivity is higher than that for electrons by the factor of ca. 1.6, reflecting the higher G(HCl) value, 23 - 25. (author)

  18. Sensitivity of planktonic and biofilm-associated Aeromonas spp. to ionizing radiation

    International Nuclear Information System (INIS)

    Nagar, Vandan; Bandekar, J.R.

    2015-01-01

    Genus Aeromonas has emerged as an important human pathogen because it causes a variety of diseases including gastroenteritis and extra-intestinal infections. Aeromonas have the ability to adhere and form biofilms on food surfaces and food contact surfaces. Biofilm formation on foods and food contact surfaces is the major reason for contamination, cross contamination and post-processing contamination of the final food product leading to food spoilage, product rejection, economic losses and food-borne diseases. Biofilms have shown high resistance to heat, desiccation, acidic condition, high salt concentration, antibiotics and other food preservatives. Earlier studies in our laboratory have shown that ionizing radiation effectively inactivates Aeromonas in different food products. However, the relative efficacy of this process against biofilm associated cells versus free-living planktonic cells of Aeromonas is not well documented. Therefore, the dose of gamma radiation required to reduce the population by 90% (D10) was calculated for planktonic and biofilm-associated A. salmonicida Y567 and A. hydrophila A331 cells. Both A. hydrophila A331 and A. salmonicida Y567 expressed significant ability to attach and grow on glass surface following incubation at 30℃ in TSB. Ionizing radiation effectively reduced the populations of both planktonic and biofilm-associated cells for both the strains. Mean cell counts of survivors and surviving fraction of planktonic and biofilm-associated cells decreased with increased irradiation doses. The D10 values of planktonic cells and biofilm cells for A. salmonicida (Y567) were 232.65 Gy and 248.41 Gy, respectively; whereas, the D10 values of planktonic cells and biofilm cells for A. hydrophila (A331) were 249.2 Gy and 240.2 Gy respectively. No significant difference in the D10 values of planktonic and biofilm associated Aeromonas was observed. The influence of the cultured state of the organism, i.e., planktonic versus biofilm associated

  19. Effect of oxygen pressure on sensitivity of CR-39 used for astronauts radiation dosimetry

    International Nuclear Information System (INIS)

    Murai, T.; Yabe, S.; Nagamatsu, A.; Tawara, H.; Kumagai, H.; Miyazawa, Y.; Kitajo, K.; Kodaira, S.; Yasuda, N.

    2006-01-01

    The personal radiation dosimeters for astronauts are exposed to low-pressure oxygen gas (0.29 atmospheres) during extra-vehicle activities. CR-39 plastic track detectors are one of the typical passive dosimeters for space radiation monitoring. We investigated change in track formation sensitivity of the antioxidant-doped CR-39 plastic with which oxygen gas comes in contact at different pressures up to 2 atmospheres for 1h to 10 days. The oxygen effect on sensitivity was measured for the C, Si and Fe ions (10-200 keV/μm) from the HIMAC heavy ion accelerator. The sensitivity is obviously sensitive to oxygen pressure at heavy-ion exposures, but not sensitive to the experience of oxygen atmosphere before and after the ion exposures. The maximum sensitivity is obtained at 0.29 atmospheres. The present experimental data suggested that the effect depends on LET of incident particles. (author)

  20. Uncertainty and Sensitivity Analysis of Afterbody Radiative Heating Predictions for Earth Entry

    Science.gov (United States)

    West, Thomas K., IV; Johnston, Christopher O.; Hosder, Serhat

    2016-01-01

    The objective of this work was to perform sensitivity analysis and uncertainty quantification for afterbody radiative heating predictions of Stardust capsule during Earth entry at peak afterbody radiation conditions. The radiation environment in the afterbody region poses significant challenges for accurate uncertainty quantification and sensitivity analysis due to the complexity of the flow physics, computational cost, and large number of un-certain variables. In this study, first a sparse collocation non-intrusive polynomial chaos approach along with global non-linear sensitivity analysis was used to identify the most significant uncertain variables and reduce the dimensions of the stochastic problem. Then, a total order stochastic expansion was constructed over only the important parameters for an efficient and accurate estimate of the uncertainty in radiation. Based on previous work, 388 uncertain parameters were considered in the radiation model, which came from the thermodynamics, flow field chemistry, and radiation modeling. The sensitivity analysis showed that only four of these variables contributed significantly to afterbody radiation uncertainty, accounting for almost 95% of the uncertainty. These included the electronic- impact excitation rate for N between level 2 and level 5 and rates of three chemical reactions in uencing N, N(+), O, and O(+) number densities in the flow field.

  1. Tumor necrosis factor alpha selectively sensitizes human immunodeficiency virus-infected cells to heat and radiation

    International Nuclear Information System (INIS)

    Wong, G.H.; McHugh, T.; Weber, R.; Goeddel, D.V.

    1991-01-01

    We report here that infection of the human T-cell line HUT-78 with human immunodeficiency virus (HIV) increases its sensitivity to heat and radiation toxicity. A possible explanation for this result may be the reduced expression of manganous superoxide dismutase (MnSOD) in HIV-infected cells compared to uninfected cells. Tumor necrosis factor alpha (TNF-alpha) further sensitizes HIV-infected cells but not uninfected cells to heat and radiation. This is consistent with the ability of TNF-alpha to induce the expression of MnSOD in uninfected but not in HIV-infected cells. HIV-infected HUT-78 cell lines engineered to overexpress MnSOD are more resistant to heat and radiation than HIV-infected cells that do not overexpress MnSOD. However, treatment with TNF-alpha still sensitizes these cells to heat and radiation

  2. Sensitivity of radiation methods of diagnosis of electric potentials in dielectric materials

    International Nuclear Information System (INIS)

    Sapozhkov, Yu.I.; Smekalin, L.F.; Yagushkin, N.I.

    1985-01-01

    On the base of the albedo method the characteristics of radiation methods of diagnosis of electric potentials inside dielectrics, such as sensitivity and resolution are considered. Investigations are carried out for electron energies of tens keV. It is shown that with energy growth the sensitivity to electric field in the dielectrics volume drops. The target atomic number growth reduces the sensitivity approximately 1/lnz. The albedo method resolution in the investigated energy range is constant. The results obtained testify to the usability radiation methods of the diagnosis for control of electric fields of dielectric structural materials in the course of their operation

  3. Amorphous chalcogenide semiconductors for solid state dosimetric systems of high-energetic ionizing radiation

    International Nuclear Information System (INIS)

    Shpotyuk, O.

    1997-01-01

    The application possibilities of amorphous chalcogenide semiconductors use as radiation-sensitive elements of high-energetic (E > 1 MeV) dosimetric systems are analysed. It is shown that investigated materials are characterized by more wide region of registered absorbed doses and low temperature threshold of radiation information bleaching in comparison with well-known analogies based on coloring oxide glasses. (author)

  4. High-Sensitivity GaN Microchemical Sensors

    Science.gov (United States)

    Son, Kyung-ah; Yang, Baohua; Liao, Anna; Moon, Jeongsun; Prokopuk, Nicholas

    2009-01-01

    Systematic studies have been performed on the sensitivity of GaN HEMT (high electron mobility transistor) sensors using various gate electrode designs and operational parameters. The results here show that a higher sensitivity can be achieved with a larger W/L ratio (W = gate width, L = gate length) at a given D (D = source-drain distance), and multi-finger gate electrodes offer a higher sensitivity than a one-finger gate electrode. In terms of operating conditions, sensor sensitivity is strongly dependent on transconductance of the sensor. The highest sensitivity can be achieved at the gate voltage where the slope of the transconductance curve is the largest. This work provides critical information about how the gate electrode of a GaN HEMT, which has been identified as the most sensitive among GaN microsensors, needs to be designed, and what operation parameters should be used for high sensitivity detection.

  5. Gimeracil sensitizes cells to radiation via inhibition of homologous recombination

    International Nuclear Information System (INIS)

    Takagi, Masaru; Sakata, Koh-ichi; Someya, Masanori; Tauchi, Hiroshi; Iijima, Kenta; Matsumoto, Yoshihisa; Torigoe, Toshihiko; Takahashi, Akari; Hareyama, Masato; Fukushima, Masakazu

    2010-01-01

    Background and purpose: 5-Chloro-2,4-dihydroxypyridine (Gimeracil) is a component of an oral fluoropyrimidine derivative S-1. Gimeracil is originally added to S-1 to yield prolonged 5-FU concentrations in tumor tissues by inhibiting dihydropyrimidine dehydrogenase, which degrades 5-FU. We found that Gimeracil by itself had the radiosensitizing effect. Methods and materials: We used various cell lines deficient in non-homologous end-joining (NHEJ) or homologous recombination (HR) as well as DLD-1 and HeLa in clonogenic assay. γ-H2AX focus formation and SCneo assay was performed to examine the effects of Gimeracil on DNA double strand break (DSB) repair mechanisms. Results: Results of γ-H2AX focus assay indicated that Gimeracil inhibited DNA DSB repair. It did not sensitize cells deficient in HR but sensitized those deficient in NHEJ. In SCneo assay, Gimeracil reduced the frequency of neo-positive clones. Additionally, it sensitized the cells in S-phase more than in G0/G1. Conclusions: Gimeracil inhibits HR. Because HR plays key roles in the repair of DSBH caused by radiotherapy, Gimeracil may enhance the efficacy of radiotherapy through the suppression of HR-mediated DNA repair pathways.

  6. Do intracellular thiol or peroxidase levels block radiation sensitization by nitrous oxide in some E. coli strains

    Energy Technology Data Exchange (ETDEWEB)

    Ewing, D.; Guilfoil, D.S.; Ohm, M.B. (Hahnemann Univ., Philadelphia, PA (USA). Dept. of Radiation Oncology and Nuclear Medicine)

    1991-01-01

    Although nitrous oxide (N{sub 2}O) is often a radiation sensitizer in procaryotic cells, it fails to sensitize some strains of bacteria, some yeast strains, and most eucaryotic cell lines. At present this inconsistency cannot be satisfactorily explained. The experiments here use eight strains of E. coli, some of which are not sensitized by N{sub 2}O, to test the hypotheses that N{sub 2}O's failure to sensitize might be based on high thiol content or on low peroxidase activity. Our data contradict those hypotheses. In addition, further data show that the strains not sensitized by N{sub 2}O contain no unique cellular component or compound which blocks damage from N{sub 2}O. (author).

  7. Do intracellular thiol or peroxidase levels block radiation sensitization by nitrous oxide in some E. coli strains?

    International Nuclear Information System (INIS)

    Ewing, D.; Guilfoil, D.S.; Ohm, M.B.

    1991-01-01

    Although nitrous oxide (N 2 O) is often a radiation sensitizer in procaryotic cells, it fails to sensitize some strains of bacteria, some yeast strains, and most eucaryotic cell lines. At present this inconsistency cannot be satisfactorily explained. The experiments here use eight strains of E. coli, some of which are not sensitized by N 2 O, to test the hypotheses that N 2 O's failure to sensitize might be based on high thiol content or on low peroxidase activity. Our data contradict those hypotheses. In addition, further data show that the strains not sensitized by N 2 O contain no unique cellular component or compound which blocks damage from N 2 O. (author)

  8. Epicatechin stimulates mitochondrial activity and selectively sensitizes cancer cells to radiation.

    Directory of Open Access Journals (Sweden)

    Hosam A Elbaz

    Full Text Available Radiotherapy is the treatment of choice for solid tumors including pancreatic cancer, but the effectiveness of treatment is limited by radiation resistance. Resistance to chemotherapy or radiotherapy is associated with reduced mitochondrial respiration and drugs that stimulate mitochondrial respiration may decrease radiation resistance. The objectives of this study were to evaluate the potential of (--epicatechin to stimulate mitochondrial respiration in cancer cells and to selectively sensitize cancer cells to radiation. We investigated the natural compound (--epicatechin for effects on mitochondrial respiration and radiation resistance of pancreatic and glioblastoma cancer cells using a Clark type oxygen electrode, clonogenic survival assays, and Western blot analyses. (--Epicatechin stimulated mitochondrial respiration and oxygen consumption in Panc-1 cells. Human normal fibroblasts were not affected. (--Epicatechin sensitized Panc-1, U87, and MIA PaCa-2 cells with an average radiation enhancement factor (REF of 1.7, 1.5, and 1.2, respectively. (--Epicatechin did not sensitize normal fibroblast cells to ionizing radiation with a REF of 0.9, suggesting cancer cell selectivity. (--Epicatechin enhanced Chk2 phosphorylation and p21 induction when combined with radiation in cancer, but not normal, cells. Taken together, (--epicatechin radiosensitized cancer cells, but not normal cells, and may be a promising candidate for pancreatic cancer treatment when combined with radiation.

  9. Clinical Radiation Sensitivity With DNA Repair Disorders: An Overview

    International Nuclear Information System (INIS)

    Pollard, Julianne M.; Gatti, Richard A.

    2009-01-01

    Adverse reactions to radiotherapy represent a confounding phenomenon in radiation oncology. These reactions are rare, and many have been associated with individuals with DNA repair disorders such as ataxia-telangiectasia and Nijmegen Breakage syndrome. A paucity of published data is available detailing such circumstances. This overview describes four exemplary situations, a comprehensive list of 32 additional cases, and some insights gleaned from this overall experience. Fanconi anemia was associated with more than one-half of the reports. The lowest dose given to a patient that resulted in a reaction was 3 Gy, given to an ataxia-telangiectasia patient. Most patients died within months of exposure. It is clear that the patients discussed in this report had complicated illnesses, in addition to cancer, and the radiotherapy administered was most likely their best option. However, the underlying DNA repair defects make conventional radiation doses dangerous. Our findings support previous wisdom that radiotherapy should either be avoided or the doses should be selected with great care in the case of these radiosensitive genotypes, which must be recognized by their characteristic phenotypes, until more rapid, reliable, and functional assays of DNA repair become available.

  10. Hydroxyurea as a radiation sensitizer in malignancies of the head and neck

    International Nuclear Information System (INIS)

    Mohanta, P.K.; Singhal, R.M.; Jindel, R.; Sharma, R.L.; Julka, P.K.

    1992-01-01

    A prospective randomized trail was undertaken to assess the efficacy of hydroxyurea as a radiation sensitizer. Disease control rates achieved significance (p<0.01) values only at 2 and 3 months post-radiation. At the end of 2 years of follow-up there was no significant difference in the disease control rate between the control and the experimental group. The toxicity in the experimental group was acceptable. One patient had severe vomiting; 13% showed severe mucositis, 4.5% had erythema of the treatment area and 40% showed dry desquamation. There seems to be no added advantage of hydroxyurea and radiation over radiation alone. (author). 12 refs., 2 tabs

  11. Estimating option values of solar radiation management assuming that climate sensitivity is uncertain.

    Science.gov (United States)

    Arino, Yosuke; Akimoto, Keigo; Sano, Fuminori; Homma, Takashi; Oda, Junichiro; Tomoda, Toshimasa

    2016-05-24

    Although solar radiation management (SRM) might play a role as an emergency geoengineering measure, its potential risks remain uncertain, and hence there are ethical and governance issues in the face of SRM's actual deployment. By using an integrated assessment model, we first present one possible methodology for evaluating the value arising from retaining an SRM option given the uncertainty of climate sensitivity, and also examine sensitivities of the option value to SRM's side effects (damages). Reflecting the governance challenges on immediate SRM deployment, we assume scenarios in which SRM could only be deployed with a limited degree of cooling (0.5 °C) only after 2050, when climate sensitivity uncertainty is assumed to be resolved and only when the sensitivity is found to be high (T2x = 4 °C). We conduct a cost-effectiveness analysis with constraining temperature rise as the objective. The SRM option value is originated from its rapid cooling capability that would alleviate the mitigation requirement under climate sensitivity uncertainty and thereby reduce mitigation costs. According to our estimates, the option value during 1990-2049 for a +2.4 °C target (the lowest temperature target level for which there were feasible solutions in this model study) relative to preindustrial levels were in the range between $2.5 and $5.9 trillion, taking into account the maximum level of side effects shown in the existing literature. The result indicates that lower limits of the option values for temperature targets below +2.4 °C would be greater than $2.5 trillion.

  12. Triggers for a high sensitivity charm experiment

    International Nuclear Information System (INIS)

    Christian, D.C.

    1994-07-01

    Any future charm experiment clearly should implement an E T trigger and a μ trigger. In order to reach the 10 8 reconstructed charm level for hadronic final states, a high quality vertex trigger will almost certainly also be necessary. The best hope for the development of an offline quality vertex trigger lies in further development of the ideas of data-driven processing pioneered by the Nevis/U. Mass. group

  13. Sensitivity of strains of Escherichia coli differing in repair capability to far UV, near UV and visible radiations

    International Nuclear Information System (INIS)

    Webb, R.B.; Brown, M.S.

    1976-01-01

    In stationary phase, strains of Escherichia coli deficient in excision (B/r Hcr) or recombination repair (K12 AB2463) were more sensitive than a repair proficient strain (B/r) to monochromatic near-ultraviolet (365nm) and visible (460 nm) radiations. The relative increase in sensitivity of mutants deficient in excision or recombination repair in comparison to the wildtype, was less at 365 nm than at 254 nm. However, a strain deficient in both excision and recombination repair (K12 AB2480) showed a large, almost equal, increase in sensitivity over mutants deficient in either excision or recombination repair at 365 nm and 254 nm. All strains tested were highly resistant to 650 nm radiation. Action spectra for lethality of strains B/r and B/r Hcr in stationary phase reveal small peaks or shoulders in the 330 to 340, 400 to 410 and 490 to 510 nm wavelength ranges. The presence of 5 micro g/ml acriflavine (an inhibitor of repair) in the plating medium greatly increased the sensitivity of strain B/r to radiation at 254, 365 and 460 nm, while strains E.coli B/r Hcr and K12 AB2463 were sensitized by small amounts. At each of the wavelengths tested, acriflavine in the plating medium had at most a small effect on E.coli K12 AB2480. Acriflavine failed to sensitize any strain tested at 650 nm. Evidence supports the interpretation that lesions induced in DNA by 365 nm and 460 nm radiations play the major role in the inactivation of E.coli by these wavelengths. Single-strand breaks (or alkali-labile bonds), but not pyrimidine dimers are candidates for the lethal DNA lesions in uvrA and repair proficient strains. At high fluences lethality may be enhanced by damage to the excision and recombination repair systems. (author)

  14. Sensitivity of strains of Escherichia coli differing in repair capability to far uv, near uv and visible radiations

    Energy Technology Data Exchange (ETDEWEB)

    Webb, R B; Brown, M S [Argonne National Lab., Ill. (USA)

    1976-11-01

    In stationary phase, strains of Escherichia coli deficient in excision (B/r Hcr) or recombination repair (K12 AB2463) were more sensitive than a repair proficient strain (B/r) to monochromatic near-ultraviolet (365nm) and visible (460 nm) radiations. The relative increase in sensitivity of mutants deficient in excision or recombination repair in comparison to the wildtype, was less at 365 nm than at 254 nm. However, a strain deficient in both excision and recombination repair (K12 AB2480) showed a large, almost equal, increase in sensitivity over mutants deficient in either excision or recombination repair at 365 nm and 254 nm. All strains tested were highly resistant to 650 nm radiation. Action spectra for lethality of strains B/r and B/r Hcr in stationary phase reveal small peaks or shoulders in the 330 to 340, 400 to 410 and 490 to 510 nm wavelength ranges. The presence of 5 micro g/ml acriflavine (an inhibitor of repair) in the plating medium greatly increased the sensitivity of strain B/r to radiation at 254, 365 and 460 nm, while strains E.coli B/r Hcr and K12 AB2463 were sensitized by small amounts. At each of the wavelengths tested, acriflavine in the plating medium had at most a small effect on E.coli K12 AB2480. Acriflavine failed to sensitize any strain tested at 650 nm. Evidence supports the interpretation that lesions induced in DNA by 365 nm and 460 nm radiations play the major role in the inactivation of E.coli by these wavelengths. Single-strand breaks (or alkali-labile bonds), but not pyrimidine dimers are candidates for the lethal DNA lesions in uvrA and repair proficient strains. At high fluences lethality may be enhanced by damage to the excision and recombination repair systems.

  15. Chemical protection from high LET radiation

    International Nuclear Information System (INIS)

    Ando, Koichi; Koike, Sachiko; Matsushita, Satoru; Kanai, Tatsuaki; Ohara, Hiroshi

    1992-01-01

    Radioprotection by WR151327 from high LET fast neutrons was investigated and compared with that from low LET radiation. Radiation damage in bone marrow, intestine, skin and leg length were all protected by a pretreatment with 400 mg/kg WR151327. Most prominent protection was observed for bone marrow, which gave a Dose Modifying Factor (DMF) of 2.2 against γ rays. Identical protection was observed between early and late radiation damage. WR151327 protected fast neutrons less efficiently than γ rays; 40% for bone marrow and 80% for skin leg. Pathological findings indicated that hyperplastic change in both dermis and epidermis associated with late skin shrinkage. Laser doppler flow-metry showed a good relationship between reduction of blood flow and late skin shrinkage. Irradiation of skin by heavy particle Carbon-12 indicated that skin shrinkage was modified by unirradiated surrounding normal tissues, which proposed a significant role of 'Volume Effect' in radiation damage. Tumor tissues were less protected by WR151327 than normal tissues. Dependence of radioprotection by WR151327 on tissue oxygen concentration is a probable reason to explain the difference between normal and tumor tissues. (author)

  16. Oyster radiation sensitivity; Sensibilidade de ostras a radiacao

    Energy Technology Data Exchange (ETDEWEB)

    Marchese, Sandra R.M. [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), SP (Brazil); Mastro, Nelida L. del [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    1996-07-01

    Various food products like oysters, crabs and shrimps have been described as possible Vibrio spp. transmitting agents. Seafood irradiation is been presented as an alternative among the different public health intervention measures to control food borne diseases. The objective of this work was to establish, firstly, the radioresistance of Crassostrea brasiliana oysters. The oysters were irradiated with Co-60 radiation with doses of 0, 1.5,3 and 6 kGy. Survival curves a function of time showed that 100% of samples irradiated with 3 kGy survived at least 6 days; among those irradiated with 6 kGy, 100% survived 3 days. These results are encouraging since a dose of 2 kGy is already effective in diminishing oyster bioburden. (author)

  17. In vivo sensitivity of the embryonic and adult neural stem cell compartments to low-dose radiation

    International Nuclear Information System (INIS)

    Barazzuol, Lara; Jeggo, Penny A.

    2016-01-01

    The embryonic brain is radiation-sensitive, with cognitive deficits being observed after exposure to low radiation doses. Exposure of neonates to radiation can cause intracranial carcinogenesis. To gain insight into the basis underlying these outcomes, we examined the response of the embryonic, neonatal and adult brain to low-dose radiation, focusing on the neural stem cell compartments. This review summarizes our recent findings. At E13.5–14.5 the embryonic neocortex encompasses rapidly proliferating stem and progenitor cells. Exploiting mice with a hypomorphic mutation in DNA ligase IV (Lig4 Y288C ), we found a high level of DNA double-strand breaks (DSBs) at E14.5, which we attribute to the rapid proliferation. We observed endogenous apoptosis in Lig4 Y288C embryos and in WT embryos following exposure to low radiation doses. An examination of DSB levels and apoptosis in adult neural stem cell compartments, the subventricular zone (SVZ) and the subgranular zone (SGZ) revealed low DSB levels in Lig4 Y288C mice, comparable with the levels in differentiated neuronal tissues. We conclude that the adult SVZ does not incur high levels of DNA breakage, but sensitively activates apoptosis; apoptosis was less sensitively activated in the SGZ, and differentiated neuronal tissues did not activate apoptosis. P5/P15 mice showed intermediate DSB levels, suggesting that DSBs generated in the embryo can be transmitted to neonates and undergo slow repair. Interestingly, this analysis revealed a stage of high endogenous apoptosis in the neonatal SVZ. Collectively, these studies reveal that the adult neural stem cell compartment, like the embryonic counterpart, can sensitively activate apoptosis

  18. High fidelity chemistry and radiation modeling for oxy -- combustion scenarios

    Science.gov (United States)

    Abdul Sater, Hassan A.

    To account for the thermal and chemical effects associated with the high CO2 concentrations in an oxy-combustion atmosphere, several refined gas-phase chemistry and radiative property models have been formulated for laminar to highly turbulent systems. This thesis examines the accuracies of several chemistry and radiative property models employed in computational fluid dynamic (CFD) simulations of laminar to transitional oxy-methane diffusion flames by comparing their predictions against experimental data. Literature review about chemistry and radiation modeling in oxy-combustion atmospheres considered turbulent systems where the predictions are impacted by the interplay and accuracies of the turbulence, radiation and chemistry models. Thus, by considering a laminar system we minimize the impact of turbulence and the uncertainties associated with turbulence models. In the first section of this thesis, an assessment and validation of gray and non-gray formulations of a recently proposed weighted-sum-of-gray gas model in oxy-combustion scenarios was undertaken. Predictions of gas, wall temperatures and flame lengths were in good agreement with experimental measurements. The temperature and flame length predictions were not sensitive to the radiative property model employed. However, there were significant variations between the gray and non-gray model radiant fraction predictions with the variations in general increasing with decrease in Reynolds numbers possibly attributed to shorter flames and steeper temperature gradients. The results of this section confirm that non-gray model predictions of radiative heat fluxes are more accurate than gray model predictions especially at steeper temperature gradients. In the second section, the accuracies of three gas-phase chemistry models were assessed by comparing their predictions against experimental measurements of temperature, species concentrations and flame lengths. The chemistry was modeled employing the Eddy

  19. Effects of peroxide and catalase on near ultraviolet radiation sensitivity in Escherichia coli strains

    International Nuclear Information System (INIS)

    Coombs, A.M.L.; Moss, S.H.

    1987-01-01

    The role of peroxide and catalase on NUV radiation sensitivity was examined in two repair competent E. coli strains, AB1157 and B/r. Exponential phase B/r is considerably more sensitive to NUV radiation than exponential phase AB1157. However, resistance to 5 mmol dm -3 H 2 O 2 was induced in both AB1157 and B/r by pretreating growing cells with 30 μmol dm -3 H 2 O 2 . Pretreatment also induced resistance to broad-band NUV radiation in these strains. The addition of catalase to the post-irradiation plating medium increased survival to the same extent as that provided by pretreatment with 30 μmol dm -3 H 2 O 2 , in both strains. The NUV radiation sensitivity seen in B/r does not appear to be due to a deficiency in enzymes that scavenge H 2 O 2 , as a catalase deficient mutant, E. coli UM1, is more resistant to NUV radiation than B/r. Also, assays for H 2 O 2 scavenging ability show little difference between AB1157 and B/r in this respect. Two hypotheses are put forward to account for the sensitivity of exponential phase B/r. Whilst it is apparent that peroxides and catalase do have a role in NUV radiation damage, it is clear that other factors also influence survival under certain conditions. (author)

  20. Specificity and sensitivity of NMR based urinary metabolic biomarker for radiation injury

    International Nuclear Information System (INIS)

    Tyagi, Ritu; Watve, Apurva; Khushu, Subash; Rana, Poonam

    2016-01-01

    Increasing burden of natural background radiation and terrestrial radionuclides is a big threat of radiation exposure to the population at large. It is necessary to develop biomarker of ionizing radiation exposure that can be used for mass screening in the event of a radiological mass casualty incident. Metabolomics has already been proven as an excellent developing prospect for capturing diseases specific metabolic signatures as possible biomarkers. The aim of the present study is to evaluate the sensitivity and specificity of the urinary metabolites after whole body radiation exposure which can further be used as early predictive marker. The PLS-DA based ROC curve depicted taurine as a biomarker of early radiation injury. This study along with other 'omics' technique will be useful to help design strategies for non-invasive radiation biodosimetry through metabolomics in human populations

  1. Sensitivity of APSIM/ORYZA model due to estimation errors in solar radiation

    Directory of Open Access Journals (Sweden)

    Alexandre Bryan Heinemann

    2012-01-01

    Full Text Available Crop models are ideally suited to quantify existing climatic risks. However, they require historic climate data as input. While daily temperature and rainfall data are often available, the lack of observed solar radiation (Rs data severely limits site-specific crop modelling. The objective of this study was to estimate Rs based on air temperature solar radiation models and to quantify the propagation of errors in simulated radiation on several APSIM/ORYZA crop model seasonal outputs, yield, biomass, leaf area (LAI and total accumulated solar radiation (SRA during the crop cycle. The accuracy of the 5 models for estimated daily solar radiation was similar, and it was not substantially different among sites. For water limited environments (no irrigation, crop model outputs yield, biomass and LAI was not sensitive for the uncertainties in radiation models studied here.

  2. Radiation sensitivity and EPR dosimetric potential of gallic acid and its esters

    Science.gov (United States)

    Tuner, Hasan; Oktay Bal, M.; Polat, Mustafa

    2015-02-01

    In the preset work the radiation sensitivities of Gallic Acid anhydrous and monohydrate, Octyl, Lauryl, and Ethyl Gallate (GA, GAm, OG, LG, and EG) were investigated in the intermediate (0.5-20 kGy) and low radiation (<10 Gy) dose range using Electron Paramagnetic Resonance (EPR) spectroscopy. While OG, LG, and EG are presented a singlet EPR spectra, their radiation sensitivity found to be very different in the intermediate dose range. At low radiation dose range (<10 Gy) only LG is found to be present a signal that easily distinguished from the noise signals. The intermediate and low dose range radiation sensitivities are compared using well known EPR dosimeter alanine. The radiation yields (G) of the interested material were found to be 1.34×10-2, 1.48×10-2, 4.14×10-2, and 6.03×10-2, 9.44×10-2 for EG, GA, GAm, OG, and LG, respectively at the intermediate dose range. It is found that the simple EPR spectra and the noticeable EPR signal of LG make it a promising dosimetric material to be used below 10 Gy of radiation dose.

  3. Constant sensitivity circuit for solid state nuclear radiation counters

    International Nuclear Information System (INIS)

    Kronenberg, S.; Erkkila, B.

    1985-01-01

    The utilization of solid state counters in tactical radiological instruments for measuring intensities and doses of fallout gamma rays offers advantages over Geiger-Mueller (GM) counters such as a much wider dynamic range and low operating voltages. Their very small size is suitable for use in miniaturized equipment. However, these devices have a serious problem if used in a mixed, fast neutron/gamma environment such as is encountered e.g. in a battlefield where tactical nuclear weapons are used and neutrons, prompt, initial gammas and fallout gammas are killing factors of comparable importance. Exposure to fast neutrons reduces seriously their sensitivity. This makes the solid state counters at this time unacceptable for use in Army tactical surveillance equipment and in other applications where according to requirements the performance must not be impaired by exposure to fast neutrons. It seems to be possible to reduce to some extent this neutron generated damage by improving the crystal counters

  4. A novel position sensitive detector for nuclear radiation. Final Report

    International Nuclear Information System (INIS)

    Kania Shah

    2006-01-01

    Current and next generation experiments in nuclear and elementary particle physics require detectors with high spatial resolution, fast response, and accurate energy information. Such detectors are required for spectroscopy, and imaging of optical and high-energy photons, charged particles, and neutrons, and are of interest not only in nuclear and high-energy physics, but also in other areas such as medical imaging, diffraction, astronomy, nuclear treaty verification, non-destructive evaluation, and geological exploration

  5. Development of high effectiveness biomimetic materials by radiation

    International Nuclear Information System (INIS)

    Nho, Youngchang; Lim, Younmook; Gwon, Huijeong; Park, Jongseok; Jeong, Sungin; Jo, Seonyoung

    2013-09-01

    The aims of this project is to develop the high-performance biomedical new materials. In the 1 st project, we have developed the polymer matrix for drug delivery systems (DDS) for mucosa membrane. We studied on the drug release behavior such as election of drug loading method for antibiotics, propolis and adrenocortic hormone valuation of drug release behavior. The oral DDS is to cure gingival disease as well as inflammation in mouth. It is expected that a new market will be created in the field of DDS for oral mucosa. The 2 nd project, we have developed the multi-functional artificial skin for substitution of animal test such as toxicity, whitening, wrinkle improvement, skin for substitution and skin sensitivity by radiation. It is expected for the above development of biocompatible artificial skin model with good physical property by using radiation technique to be useful for the future biology, cosmetics and pharmaceutical research

  6. High resistance of some oligotrophic bacteria to ionizing radiation

    International Nuclear Information System (INIS)

    Nikitin, D.I.; Tashtemirova, M.A.; Pitryuk, I.A.; Sorokin, V.V.; Oranskaya, M.S.; Nikitin, L.E.

    1994-01-01

    The resistance of seven cultures of eutrophic and oligotrophic bacteria to gamma radiation (at doses up to 360 Gy) was investigated. The bacteria under study were divided into three groups according to their survival ability after irradiation. Methylobacterium organophilum and open-quotes Pedodermatophilus halotoleransclose quotes (LD 50 = 270 Gy) were highly tolerant. By their tolerance, these organisms approached Deinococcus radiodurans. Aquatic ring-shaped (toroidal) bacteria Flectobacillus major and open-quotes Arcocella aquaticaclose quotes (LD 5 = 173 and 210 Gy, respectively) were moderately tolerant. Eutrophic Pseudomonas fluorescens and Escherichia coli (LD 50 = 43 and 38 Gy, respectively) were the most sensitive. X-ray microanalysis showed that in tolerant bacteria the intracellular content of potassium increased and the content of calcium decreased after irradiation. No changes in the element composition of the eutrophic bacterium E. coli were detected. Possible mechanisms of the resistance of oligotrophic bacteria to gamma radiation are discussed

  7. Development of high effectiveness biomimetic materials by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Nho, Youngchang; Lim, Younmook; Gwon, Huijeong; Park, Jongseok; Jeong, Sungin; Jo, Seonyoung

    2013-09-15

    The aims of this project is to develop the high-performance biomedical new materials. In the 1{sup st} project, we have developed the polymer matrix for drug delivery systems (DDS) for mucosa membrane. We studied on the drug release behavior such as election of drug loading method for antibiotics, propolis and adrenocortic hormone valuation of drug release behavior. The oral DDS is to cure gingival disease as well as inflammation in mouth. It is expected that a new market will be created in the field of DDS for oral mucosa. The 2{sup nd} project, we have developed the multi-functional artificial skin for substitution of animal test such as toxicity, whitening, wrinkle improvement, skin for substitution and skin sensitivity by radiation. It is expected for the above development of biocompatible artificial skin model with good physical property by using radiation technique to be useful for the future biology, cosmetics and pharmaceutical research.

  8. Highly heat removing radiation shielding material

    International Nuclear Information System (INIS)

    Asano, Norio; Hozumi, Masahiro.

    1990-01-01

    Organic materials, inorganic materials or metals having excellent radiation shielding performance are impregnated into expanded metal materials, such as Al, Cu or Mg, having high heat conductivity. Further, the porosity of the expanded metals and combination of the expanded metals and the materials to be impregnated are changed depending on the purpose. Further, a plurality of shielding materials are impregnated into the expanded metal of the same kind, to constitute shielding materials. In such shielding materials, impregnated materials provide shielding performance against radiation rays such as neutrons and gamma rays, the expanded metals provide heat removing performance respectively and they act as shielding materials having heat removing performance as a whole. Accordingly, problems of non-informity and discontinuity in the prior art can be dissolved be provide materials having flexibility in view of fabrication work. (T.M.)

  9. Intrinsic and extrinsic variables affecting sensitivity to radiation carcinogenesis

    International Nuclear Information System (INIS)

    Yuhas, J.M.

    1979-01-01

    Mathematical models relating observed yield of cancers vs administered radiation dose have become popular in recent years, especially as means of predicting hazards associated with exposure conditions which are beyond the realm of practical experimentation. While the validity of these predictions remains a controversy, these models, especially the αD + βD 2 model, have more recently been used to infer the mechanism(s) underlying the carcinogenic process. Through the analysis of simple experimental systems, we demonstrate in this report that aD + bD 2 kinetics can result from injury to the cells which eventually develop into the cancer (target cells) or from injury to those cells which affect target cell survival. Further, these kinetics can fail to predict the consequences of dose protraction, largely due to the fact that transformation increases with dose, while survival decreases. The role of these models in helping to develop an understanding of mechanisms should be restricted, therefore, to the formulation of basic hypotheses which are subject to direct testing in the laboratory

  10. Low Power and High Sensitivity MOSFET-Based Pressure Sensor

    International Nuclear Information System (INIS)

    Zhang Zhao-Hua; Ren Tian-Ling; Zhang Yan-Hong; Han Rui-Rui; Liu Li-Tian

    2012-01-01

    Based on the metal-oxide-semiconductor field effect transistor (MOSFET) stress sensitive phenomenon, a low power MOSFET pressure sensor is proposed. Compared with the traditional piezoresistive pressure sensor, the present pressure sensor displays high performances on sensitivity and power consumption. The sensitivity of the MOSFET sensor is raised by 87%, meanwhile the power consumption is decreased by 20%. (cross-disciplinary physics and related areas of science and technology)

  11. Effect of ''pasteurizing'' doses of ionizing radiations on drug sensitivity of microbes isolated at pharmacentical factory

    International Nuclear Information System (INIS)

    Pavlov, E.P.; Shcheglova, S.G.; Sedov, V.V.

    1978-01-01

    The effect of ionizing radiations on drug sensitivity of microorganisms has been investigated, particularly, the influence of pasteurizing'' doses of ionizing radia''ons on the drug sensitivity of microorganisms isolated at a Moscow pharmaceutical factory to a number of widely used antibiotics. 250 krad single irradiation of dry microbial culture resulted in a change of the antibiotic sensitivity in 0.5% of 686 strains studied. All changes were toward the appearance of sensitivity to one or several antibiotics. When cultures were irradiated 3 times, this value increased up to 9%. In no case the appearance of resistance to antibiotics was observed

  12. Sensitivity of a soil-plant-atmosphere model to changes in air temperature, dew point temperature, and solar radiation

    Energy Technology Data Exchange (ETDEWEB)

    Luxmoore, R.J. (Oak Ridge National Lab.,TN); Stolzy, J.L.; Holdeman, J.T.

    1981-01-01

    Air temperature, dew point temperature and solar radiation were independently varied in an hourly soil-plant-atmosphere model in a sensitivity analysis of these parameters. Results suggested that evapotranspiration in eastern Tennessee is limited more by meteorological conditions that determine the vapor-pressure gradient than by the necessary energy to vaporize water within foliage. Transpiration and soil water drainage were very sensitive to changes in air and dew point temperature and to solar radiation under low atmospheric vapor-pressure deficit conditions associated with reduced air temperature. Leaf water potential and stomatal conductance were reduced under conditions having high evapotranspiration. Representative air and dew point temperature input data for a particular application are necessary for satisfactory results, whereas irradiation may be less well characterized for applications with high atmospheric vapor-pressure deficit. The effects of a general rise in atmospheric temperature on forest water budgets are discussed.

  13. Radiation-hard silicon photonics for high energy physics and beyond

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    Silicon photonics (SiPh) is currently being investigated as a promising technology for future radiation hard optical links. The possibility of integrating SiPh devices with electronics and/or silicon particle sensors as well as an expected very high resistance against radiation damage make this technology particularly interesting for potential use close to the interaction points in future in high energy physics experiments and other radiation-sensitive applications. The presentation will summarize the outcomes of the research on radiation hard SiPh conducted within the ICE-DIP projected.

  14. Effect of gamma radiation dose and sensitizer on the physical properties of irradiated natural rubber latex

    International Nuclear Information System (INIS)

    Komgrit, R.; Thawat, C.; B, Tripob; Wirach, T.

    2009-07-01

    Full text: The vulcanization of natural rubber latex can be induced by gamma radiation, which enhances cross-linking within the rubber matrix. The purpose of this research is to investigate the effect of gamma radiation dose and sensitizers on the physical properties of irradiated natural rubber. Three sensitizers n-butyl acrylate (n-B A), tetrachloroethylene (C 2 Cl 4 ) and trichloromethane (CHCl 3 ) were mixed with natural rubber latex before irradiation with gamma ray dose varied from 14 to 22 kGy. Results showed that the mixture of three sensitizers with specific ratios effectively induced the cross-linking of natural rubber latex. The cross-linking ratio and improved physical properties increased with increasing gamma dose. Therefore, the mixture ratios of n-B A, C 2 Cl 4 and CHCl 3 have shown to be a critical parameter in the vulcanization of natural rubber latex by gamma radiation

  15. Relationship of radiation sensitivity and aberrant DNA synthesis in repair deficient CHO cells

    International Nuclear Information System (INIS)

    Newman, C.N.; Hagler, H.; Miller, J.H.

    1986-11-01

    Comparison of alkaline sucrose gradient profiles of pulse-labeled DNA from a normal CHO cell line and its radiation-sensitive mutant, xrs-5, reveals significant differences in the replicon elongation/maturation process in these two cells. During a one hr period of growth subsequent to labeling, the molecular weight of pulse-labeled DNA from the mutant cell increases considerably more rapidly than that of the parent cell. For xrs-5, the presence of 2 mM deoxycytidine (CdR) in the culture medium reduces the replication rate to one approaching that of the parent cell growing in the standard medium. Corresponding uv resistance of the mutant likewise increases to nearly that of the parent cell line. These results suggest that the locus conferring radiation sensitivity to xrs-5 affects the DNA replisome complex and that replicative activity and radiation sensitivity are jointly modulated by CdR. 19 refs., 4 figs

  16. Two mutations which confer temperature-sensitive radiation sensitivity in the yeast Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Ho, K.S.Y.; Mortimer, R.K.

    1975-01-01

    X-ray survival curves for two mutations, rad54 and rad55, in the yeast Saccharomyces cerevisiae are presented. These mutations confer temperature sensitive X-ray sensitivity; that is, rad54 and rad55 strains display a wild type X-ray survival response at permissive temperatures and a radiosensitive X-ray survival response at restrictive temperatures. The survival response of cells which were shifted from a permissive to a restrictive temperature or vice versa at various post-irradiation times indicates that repair and fixation of X-ray induced lesions is largely complete three hours after X-irradiation. Experiments to determine the utilization sequence of the rad54 and rad55 gene products in the repair of X-ray induced damage suggest that the two products are required in an interdependent manner

  17. Sensitivity of hyperthermia-treated human cells to killing by ultraviolet or gamma radiation

    International Nuclear Information System (INIS)

    Mitchel, R.E.; Smith, B.P.; Wheatly, N.; Chan, A.; Child, S.; Paterson, M.C.

    1985-01-01

    Human xeroderma pigmentosum (XP) or Fanconi anemia (FA) fibroblasts displayed shouldered 45 0 C heat survival curves not significantly different from normal fibroblasts, a result similar to that previously found for ataxia telangiectasia (AT) cells, indicating heat resistance is not linked to either uv or low-LET ionizing radiation resistance. Hyperthermia (45 0 C) sensitized normal and XP fibroblasts to killing by gamma radiation but failed to sensitize the cells to the lethal effects of 254 nm uv radiation. Thermal inhibition of repair of ionizing radiation lesions but not uv-induced lesions appears to contribute synergistically to cell death. The thermal enhancement ratio (TER) for the synergistic interaction of hyperthermia (45 0 C, 30 min) and gamma radiation was significantly lower in one FA and two strains (TER = 1.7-1.8) than that reported previously for three normal strains (TER = 2.5-3.0). These XP and FA strains may be more gamma sensitive than normal human fibroblasts. Since hyperthermia treatment only slightly increases the gamma-radiation sensitivity of ataxia telangiectasia (AT) fibroblasts compared to normal strains, it is possible that the degree of thermal enhancement attainable reflects the genetically inherent ionizing radiation repair capacity of the cells. The data indicate that both repair inhibition and particular lesion types are required for lethal synergism between heat and radiation. We therefore postulate that the transient thermal inhibition of repair results in the conversion of gamma-induced lesions to irrepairable lethal damage, while uv-type damage can remain unaltered during this period

  18. Radiation collimator for use with high energy radiation beams

    International Nuclear Information System (INIS)

    Malak, S.P.

    1978-01-01

    A collimator is described for use with a beam of radiation, and in particular, for use in controlling the cross-sectional size and shape of the radiation beam and intercepting undesired off-focus radiation in an x-ray apparatus. The collimator is positioned adjacent to the source of radiation and embodies a plurality longitudinally extending leaves pivotally mounted on and between two supports, the leaves move about their pivots to close overlapping relation to define a hollow cone. The cone defines an aperture at its narrow end which can be adjusted in size and shape by rotation of the two supports which are adaptable to being moved one relative to the other, to cause an expansion or contraction of the hollow cone and correspondingly an increase or decrease of the cross-sectional size and/or shape of the radiation beam passing through the aperture

  19. Effect of ionizing radiation on properties of acrylic pressure sensitive adhesives

    International Nuclear Information System (INIS)

    Panta, P.P.; Zimek, Z.A.; Giuszewski, W.; Kowalewski, R.; Wojtynska, E.; Wnuk, A.

    1998-01-01

    Pressure-sensitive adhesives for technical application are widely produced. The biological properties of adhesives depend on the type of monomers used. The available literature data as experience of the authors of this study in the area of pressure-sensitive acrylic adhesive, polymers used in medicine, polymerisation in aqueous media, radiation sterilization, permit to make an assumption that it is possible to elaborate the technology of production of pressure-sensitive adhesives in aqueous emulsion for medical applications. Identification of phenomena influencing the adhesive properties, especially its adhesion, cohesion, tack and durability is of great importance. The control of polymer structure is performed by means of adequate selection of conditions of synthesis and parameters of radiation processing. The authors investigate the influence on the final products of such factors as the type and amount of monomers used, their mutual ratio, as well as the ratio monomers and the dose of ionising radiation. There is no available literature information concerning the investigation of resistance of acrylic emulsion adhesive to sterilisation by electron beam. It is known from unpublished research that some adhesives are resistant to radiation, while others undergo destruction. It probably depends on the composition of emulsion, specifically on the additives which modify adhesives. Simultaneous achievement of good cohesion and adhesion in the case of such types of pressure sensitive adhesives is very difficult pressure sensitive adhesives is very difficult

  20. Sensitivity to ionizing radiation and chemotherapeutic agents in gemcitabine-resistant human tumor cell lines

    International Nuclear Information System (INIS)

    Bree, Chris van; Kreder, Natasja Castro; Loves, Willem J.P.; Franken, Nicolaas A.P.; Peters, Godefridus J.; Haveman, Jaap

    2002-01-01

    Purpose: To determine cross-resistance to anti-tumor treatments in 2',2'difluorodeoxycytidine (dFdC, gemcitabine)-resistant human tumor cells. Methods and Materials: Human lung carcinoma cells SW-1573 (SWp) were made resistant to dFdC (SWg). Sensitivity to cisplatin (cDDP), paclitaxel, 5-fluorouracil (5-FU), methotrexate (MTX), cytarabine (ara-C), and dFdC was measured by a proliferation assay. Radiosensitivity and radioenhancement by dFdC of this cell panel and the human ovarian carcinoma cell line A2780 and its dFdC-resistant variant AG6000 were determined by clonogenic assay. Bivariate flowcytometry was performed to study cell cycle changes. Results: In the SWg, a complete deoxycytidine kinase (dCK) deficiency was found on mRNA and protein level. This was accompanied by a 10-fold decrease in dCK activity which resulted in the >1000-fold resistance to dFdC. Sensitivity to other anti-tumor drugs was not altered, except for ara-C (>100-fold resistance). Radiosensitivity was not altered in the dFdC-resistant cell lines SWg and AG6000. High concentrations (50-100 μM dFdC) induced radioenhancement in the dFdC-resistant cell lines similar to the radioenhancement obtained at lower concentrations (10 nM dFdC) in the parental lines. An early S-phase arrest was found in all cell lines after dFdC treatment where radioenhancement was achieved. Conclusions: In the dFdC-resistant lung tumor cell line SWg, the deficiency in dCK is related to the resistance to dFdC and ara-C. No cross-resistance was observed to other anti-tumor drugs used for the treatment in lung cancer. Sensitivity to ionizing radiation was not altered in two different dFdC-resistant cell lines. Resistance to dFdC does not eliminate the ability of dFdC to sensitize cells to radiation

  1. Cryogenic semiconductor high-intensity radiation monitors

    International Nuclear Information System (INIS)

    Palmieri, V.G.; Bell, W.H.; Borer, K.; Casagrande, L.; Da Via, C.; Devine, S.R.H.; Dezillie, B.; Esposito, A.; Granata, V.; Hauler, F.; Jungermann, L.; Li, Z.; Lourenco, C.; Niinikoski, T.O.; Shea, V. O'; Ruggiero, G.; Sonderegger, P.

    2003-01-01

    This paper describes a novel technique to monitor high-intensity particle beams by means of a semiconductor detector. It consists of cooling a semiconductor detector down to cryogenic temperature to suppress the thermally generated leakage current and to precisely measure the integrated ionization signal. It will be shown that such a device provides very good linearity and a dynamic range wider than is possible with existing techniques. Moreover, thanks to the Lazarus effect, extreme radiation hardness can be achieved providing in turn absolute intensity measurements against precise calibration of the device at low beam flux

  2. Beam size measurement at high radiation levels

    International Nuclear Information System (INIS)

    Decker, F.J.

    1991-05-01

    At the end of the Stanford Linear Accelerator the high energy electron and positron beams are quite small. Beam sizes below 100 μm (σ) as well as the transverse distribution, especially tails, have to be determined. Fluorescent screens observed by TV cameras provide a quick two-dimensional picture, which can be analyzed by digitization. For running the SLAC Linear Collider (SLC) with low backgrounds at the interaction point, collimators are installed at the end of the linac. This causes a high radiation level so that the nearby cameras die within two weeks and so-called ''radiation hard'' cameras within two months. Therefore an optical system has been built, which guides a 5 mm wide picture with a resolution of about 30 μm over a distance of 12 m to an accessible region. The overall resolution is limited by the screen thickness, optical diffraction and the line resolution of the camera. Vibration, chromatic effects or air fluctuations play a much less important role. The pictures are colored to get fast information about the beam current, size and tails. Beside the emittance, more information about the tail size and betatron phase is obtained by using four screens. This will help to develop tail compensation schemes to decrease the emittance growth in the linac at high currents. 4 refs., 2 figs

  3. Novel charge sensitive preamplifier without high-value feedback resistor

    International Nuclear Information System (INIS)

    Xi Deming

    1992-01-01

    A novel charge sensitive preamplifier is introduced. The method of removing the high value feedback resistor, the circuit design and analysis are described. A practical circuit and its measured performances are provided

  4. Evaluation of radiation sensitivity and mating performance of Glossina brevipalpis males.

    Directory of Open Access Journals (Sweden)

    Chantel J de Beer

    2017-03-01

    Full Text Available Area-wide integrated pest management strategies that include a sterile insect technique component have been successfully used to eradicate tsetse fly populations in the past. To ensure the success of the sterile insect technique, the released males must be adequately sterile and be able to compete with their native counterparts in the wild.In the present study the radiation sensitivity of colonised Glossina brevipalpis Newstead (Diptera; Glossinidae males, treated either as adults or pupae, was assessed. The mating performance of the irradiated G. brevipalpis males was assessed in walk-in field cages. Glossina brevipalpis adults and pupae were highly sensitive to irradiation, and a dose of 40 Gy and 80 Gy induced 93% and 99% sterility respectively in untreated females that mated with males irradiated as adults. When 37 to 41 day old pupae were exposed to a dose of 40 Gy, more than 97% sterility was induced in untreated females that mated with males derived from irradiated pupae. Males treated as adults with a dose up to 80 Gy were able to compete successfully with untreated fertile males for untreated females in walk-in field cages.The data emanating from this field cage study indicates that, sterile male flies derived from the colony of G. brevipalpis maintained at the Agricultural Research Council-Onderstepoort Veterinary Institute in South Africa are potential good candidates for a campaign that includes a sterile insect technique component. This would need to be confirmed by open field studies.

  5. Comparison of two different techniques on the human lymphocytes morphology and sensitivity to gamma radiation

    International Nuclear Information System (INIS)

    Kol, R.

    1985-02-01

    The lymphocytes in the peripheral blood are divided into two main subclasses: T cells and B cells. These differ from each other in function and in their sensitivity to radiation. The effort to study which group is more sensitive to radiation has resulted in many contradictory results. In the present study we examined whether the methods that are used to separate the lymphocytes from the whole blood, before their separation into subclasses, have an effect on the cells and whether this might contribute to the contradictory results. Blood samples were taken from several normal donors and each sample was devided into two fractions. Lymphocytes in each fraction were separated by one of the two following methods: a) sedimentation of erythrocytes by gravitation; b) separation on Ficoll-Paque density gradient. For cells obtained by these two methods, the ultrastructure was examined by electron microscopy and their ability to incorporate radioactive thymidine was measured. Samples separated on Ficoll-Paque showed a subpopulation with morphological changes similar to those occuring in lymphocytes undergoing stimulation. Unstimulated cells separated on Ficoll-Paque showed greater sensitivity to radiation. The effect of gamma radiation on the capability of lymphocytes to undergo transformation in response to three mitogens; PHA, PWM and Con A was examined. Different mitogens stimulate different lymphocytes subpopulations. There was no difference between the two separation methods regarding the sensitivity to gamma radiation of stimulation by PAH and PWM. The transformation by Con A of lymphocytes separated on Ficoll-Paque was more radiosensitive. This could indicate that the separation by Ficoll-Paque density gradient causes a selective depletion of T lymphocytes that react with Con A and are considered more radioresistant. The use of different methods for separating lymphocytes from whole blood- each has a different influence on the cells- can contribute to contradictory

  6. Portable radiation meters evaluation in high rates of air kerma

    International Nuclear Information System (INIS)

    Damatto, Willian B.; Potiens, Maria da Penha A.; Vivolo, Vitor

    2015-01-01

    A set of portable meters of ionizing radiation high rates of air kerma (teletectors) commonly used in emergencies in Brazil and sent to the Calibration Laboratory of IPEN were under several tests and analyst is parameters for the detectors behavior were established, specifying their sensitivities and operating characteristics. Applied tests were: reading equipment variation with battery voltage, geotropism effect, energy dependence, the angular dependence and overload. Thus it was possible to determine the most common characteristic found in these equipment (quality control programs). The behavior of 17 portable meters was analyzed and in this study, 10 of them have been tested. It was performed to characterize the gamma irradiating system (radiation dosimetry field) that possesses higher activity in teletectors for testing of larger measuring range. New calibration criteria were established following international recommendations. Therefore, it was made the improvement of the quality control programme of portable meters of ionizing radiation high rates of air kerma calibration laboratory, benefiting the users of such equipment with better consistent calibration measurements. (author)

  7. Microbiology of the surface water samples in the high background radiation areas of Ramsar, Iran

    International Nuclear Information System (INIS)

    Motamedifar, Mohammad; Zamani, Khosrow; Sedigh, Hadi; Mortazavi, Seyed Mohammad Javad; Taeb, Shahram; Haghani, M.; Mortazavi, Seyed Ali Reza; Soofi, Amir

    2014-01-01

    Residents of high background radiation areas of Ramsar have lived in these areas for many generations and received radiation doses much higher than the dose limit recommended by ICRP for radiation workers. The radioactivity of the high background radiation areas of Ramsar is reported to be due to 226 Ra and its decay products, which have been brought to the surface by the waters of hot springs. Over the past years the department has focused on different aspects of the health effects of the elevated levels of natural radiation in Ramsar. This study was aimed to perform a preliminary investigation on the bioeffects of exposure to elevated levels of natural radiation on the microbiology of surface water samples. Water samples were collected from surface water streams in Talesh Mahalleh district, Ramsar as well as a nearby area with normal levels of background radiation. Only two strains of bacteria, that is, Providencia stuartii and Shimwellia blattae, could be isolated from the water samples collected from high background radiation areas, while seven strains (Escherichia coli, Enterobacter asburiae, Klebsiella pneumoniae, Shigella dysenteriae, Buttiauxella agerstis, Tatumella punctuata and Raoultella ornithinolytica) were isolated from the water samples collected from normal background radiation areas. All the bacteria isolated from water samples of high and normal background radiation areas were sensitive to ultraviolet radiation, heat, betadine, alcohol, and deconex. Although other investigators have reported that bacteria isolated from hot springs show radioresistance, the results reported here do not reveal any adaptive response. (author)

  8. Cherenkov radiation-based three-dimensional position-sensitive PET detector: A Monte Carlo study.

    Science.gov (United States)

    Ota, Ryosuke; Yamada, Ryoko; Moriya, Takahiro; Hasegawa, Tomoyuki

    2018-05-01

    Cherenkov radiation has recently received attention due to its prompt emission phenomenon, which has the potential to improve the timing performance of radiation detectors dedicated to positron emission tomography (PET). In this study, a Cherenkov-based three-dimensional (3D) position-sensitive radiation detector was proposed, which is composed of a monolithic lead fluoride (PbF 2 ) crystal and a photodetector array of which the signals can be readout independently. Monte Carlo simulations were performed to estimate the performance of the proposed detector. The position- and time resolution were evaluated under various practical conditions. The radiator size and various properties of the photodetector, e.g., readout pitch and single photon timing resolution (SPTR), were parameterized. The single photon time response of the photodetector was assumed to be a single Gaussian for the simplification. The photo detection efficiency of the photodetector was ideally 100% for all wavelengths. Compton scattering was included in simulations, but partly analyzed. To estimate the position at which a γ-ray interacted in the Cherenkov radiator, the center-of-gravity (COG) method was employed. In addition, to estimate the depth-of-interaction (DOI) principal component analysis (PCA), which is a multivariate analysis method and has been used to identify the patterns in data, was employed. The time-space distribution of Cherenkov photons was quantified to perform PCA. To evaluate coincidence time resolution (CTR), the time difference of two independent γ-ray events was calculated. The detection time was defined as the first photon time after the SPTR of the photodetector was taken into account. The position resolution on the photodetector plane could be estimated with high accuracy, by using a small number of Cherenkov photons. Moreover, PCA showed an ability to estimate the DOI. The position resolution heavily depends on the pitch of the photodetector array and the radiator

  9. Synthesis and TL/OSL properties of a novel high-sensitive blue-emitting LiSrPO{sub 4}:Eu{sup 2+} phosphor for radiation dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Palan, C.B.; Koparkar, K.A.; Omanwar, S.K. [Sant Gadge Baba Amravati University, Department of Physics, Amravati (India); Bajaj, N.S. [Toshniwal Arts, Commerce and Science College, Sengoan, Hingoli District, MH (India); Soni, A. [Bhabha Atomic Research Centre, Radiological Physics and Advisory Division, Mumbai (India)

    2016-07-15

    In this study, a series of Eu{sup 2+}-doped LiSrPO{sub 4} phosphors were synthesized via solid-state method. The structural and morphological characterizations were done through X-ray diffraction and scanning electronic microscope. Additionally, the photoluminescence (PL), thermoluminescence (TL) and optically stimulated luminescence (OSL) behaviours of LiSrPO{sub 4}:Eu{sup 2+} phosphors were studied. The LiSrPO{sub 4}:Eu{sup 2+} phosphor shows OSL sensitivity about 8 times than that of α-Al{sub 2}O{sub 3}:C phosphor and 6 times than that of LiMgPO{sub 4}:Tb{sup 3+}, B phosphor. Moreover, TL sensitivity was about 15 times more as compared to α-Al{sub 2}O{sub 3}:C phosphor. The kinetic parameters of TL curve were calculated using peak shape method. In TL/OSL mode, dose-response was almost linear nature, in the range of measurement. The minimum detectable dose was found to be 25.18 μGy with 3σ of background. Also, reusability was also studies, which shows the phosphor can be reusable for 10 cycles with 0.1 % change in OSL output. (orig.)

  10. Irradiation of amelanotic melanoma cells with 532 nm high peak power pulsed laser radiation in the presence of the photothermal sensitizer Cu(II)-hematoporphyrin: a new approach to cell photoinactivation.

    Science.gov (United States)

    Soncin, M; Busetti, A; Fusi, F; Jori, G; Rodgers, M A

    1999-06-01

    Cu(II)-hematoporphyrin (CuHp) was efficiently accumulated by B78H1 amelanotic melanoma cells upon incubation with porphyrin concentrations up to 52 microM. When the cells incubated for 18 h with 13 microM CuHp were irradiated with 532 nm light from a Q-switched Nd: YAG laser operated in a pulsed mode (10 ns pulses, 10 Hz) a significant decrease in cell survival was observed. The cell photoinactivation was not the consequence of a photodynamic process, as CuHp gave no detectable triplet signal upon laser flash photolysis excitation and no decrease in cell survival was observed upon continuous wave irradiation. Thus, it is likely that CuHp sensitization takes place by photothermal pathways. The efficiency of the photoprocess was modulated by different parameters; thus, while varying the amount of added CuHp in the 3.25-26 microM range had little effect, pulse energies larger than 50 mJ and irradiation times of at least 120 s were necessary to induce a cell inactivation of about 50%. The porphyrin-cell incubation time prior to irradiation had a major influence on cell survival, suggesting that the nature of the CuHp microenvironment can control the efficiency of photothermal sensitization.

  11. Inhibition of ERK1/2 or AKT Activity Equally Enhances Radiation Sensitization in B16F10 Cells

    Science.gov (United States)

    Kalal, Bhuvanesh Sukhlal; Fathima, Faraz; Pai, Vinitha Ramanath; Sanjeev, Ganesh; Krishna, Chilakapati Murali; Upadhya, Dinesh

    2018-01-01

    Background The aim of the study was to evaluate the radiation sensitizing ability of ERK1/2, PI3K-AKT and JNK inhibitors in highly radiation resistant and metastatic B16F10 cells which carry wild-type Ras and Braf. Methods Mouse melanoma cell line B16F10 was exposed to 1.0, 2.0 and 3.0 Gy of electron beam radiation. Phosphorylated ERK1/2, AKT and JNK levels were estimated by ELISA. Cells were exposed to 2.0 and 3.0 Gy of radiation with or without prior pharmacological inhibition of ERK1/2, AKT as well as JNK pathways. Cell death induced by radiation as well as upon inhibition of these pathways was measured by TUNEL assay using flow cytometry. Results Exposure of B16F10 cells to 1.0, 2.0 and 3.0 Gy of electron beam irradiation triggered an increase in all the three phosphorylated proteins compared to sham-treated and control groups. B16F10 cells pre-treated with either ERK1/2 or AKT inhibitors equally enhanced radiation-induced cell death at 2.0 as well as 3.0 Gy (P < 0.001), while inhibition of JNK pathway increased radiation-induced cell death to a lesser extent. Interestingly combined inhibition of ERK1/2 or AKT pathways did not show additional cell death compared to individual ERK1/2 or AKT inhibition. This indicates that ERK1/2 or AKT mediates radiation resistance through common downstream molecules in B16F10 cells. Conclusions Even without activating mutations in Ras or Braf genes, ERK1/2 and AKT play a critical role in B16F10 cell survival upon radiation exposure and possibly act through common downstream effector/s. PMID:29581812

  12. Ploidy and liquid-holding recovery of yeasts sensitive to radiation and nitrous acid

    International Nuclear Information System (INIS)

    Arman, I.P.; Dutova, T.A.

    1975-01-01

    NA-Inactivation of isogeneic yeasts Sacch. cerevisiae from the collection of LIYaF, normal and sensitive to radiation and Na (xrs1-5 mutation), was studied as a function of the ploidy of the genome and the conditions of incubation after the influence of the mutagen. Normal cells of highly homozygous PG strains exhibit a protective effect of ploidy: the haploid is the most sensitive to the inactivating action of NA, and with increasing number of chromosome sets the resistance increases substantially. With a different polyploid series of yeasts of the same origin, where di-, tri-, and tetraploids are homozygous for the mutation xrs1-5, this effect is absent. Moreover, the doubling of the genome leads to a sharp increase in the sensitivity of the cells to NA, while the shape of the dose-versus-effect curves becomes exponential, in contrast to sigmoid for the initial control strains. This fact of the ''reverse effect of ploidy'' is evidence of an impairment of the reapir of dominant lethals - the basic cause of death of diploid and polyploid cells - in the xrs1-5 strains. Exposure of yeasts in buffer for 24 h (LHR conditions) after the influence of NA modifies the level of inactivation, depending on the genotype and ploidy of the cells. In yeast strains of a different origin (from Berkeley, United States) with a normal sensitivity to NA (n, 2n, 3n), the survival under LHR conditions is practically unchanged for 24 h. The haploids of highly homozygous strains (LIYaF) - normal and xrs1-5 mutant - also do not recover. However, diploidizationand a further increase in the number of genomes leads to the fact that the death under LH conditions increases sharply in normal highly homozygous yeasts (PG) - by at least an order of magnitude in 24 h of incubation in buffer; in this case the titer of the cells remains constant, while the loss of viability is proportional to the time. A significant effect of recovery is detected in homozygotes for the xrs1 mutation (2n, 3n, 4n). It

  13. The influence of radiolytic sensitizers in natural rubber latex vulcanization induced by ionizing radiation

    International Nuclear Information System (INIS)

    Guedes, S.M.L.; Souza, A. de

    1991-01-01

    This work made on radiation vulcanization of natural rubber latex process by gamma rays from 60 Co source and electron beam of 1.5 MeV, 25 m A by Dynamitron, instead of classic process using sulfur. The experiment was carried out to study the influence of sensitizers (C Cl 4 and n-butyl acrylate) and was reported the vulcanization dose for each sensitizers, related to maximum tensile strength. The results show the possibility to introduce the volatile sensitizer (n-butyl acrylate) instead of C Cl 4 (toxic) in industry applications. (author)

  14. Differential sensitivity to natural ultraviolet radiation among phytoplankton species in Arctic lakes (Spitsbergen, Norway)

    NARCIS (Netherlands)

    Donk, van E.; Faafeng, B.A.; Lange, de H.J.

    2001-01-01

    Incubation experiments demonstrated a differential sensitivity to natural UV-radiation among the dominant phytoplankton species from three Arctic lakes, situated near Ny-Ålesund, Spitsbergen (79° N). The growth of small chlorophytes, diatoms and picocyanobacteria from two oligotrophic lakes was

  15. A high-sensitivity neutron counter and waste-drum counting with the high-sensitivity neutron instrument

    International Nuclear Information System (INIS)

    Hankins, D.E.; Thorngate, J.H.

    1993-04-01

    At Lawrence Livermore National Laboratory (LLNL), a highly sensitive neutron counter was developed that can detect and accurately measure the neutrons from small quantities of plutonium or from other low-level neutron sources. This neutron counter was originally designed to survey waste containers leaving the Plutonium Facility. However, it has proven to be useful in other research applications requiring a high-sensitivity neutron instrument

  16. Inhibition of autophagy induced by TSA sensitizes colon cancer cell to radiation.

    Science.gov (United States)

    He, Gang; Wang, Yan; Pang, Xueli; Zhang, Bo

    2014-02-01

    Radiotherapy is one of the main treatments for clinical cancer therapy. However, its application was limited due to lack of radiosensitivity in some cancers. Trichostatin A (TSA) is a classic histone deacetylases inhibitor (HDACi) that specifically inhibits the biochemical functions of HDAC and is demonstrated to be an active anticancer drug. However, whether it could sensitize colon cancer to radiation is not clear. Our results showed that TSA enhanced the radiosensitivity of colon cancer cells as determined by CCK-8 and clonogenic survival assay. Moreover, apoptotic cell death induced by radiation was enhanced by TSA treatment. Additionally, TSA also induced autophagic response in colon cancer cells, while autophagy inhibition led to cell apoptosis and enhanced the radiosensitivity of colon cancer cells. Our data suggested that inhibition of cytoprotective autophagy sensitizes cancer cell to radiation, which might be further investigated for clinical cancer radiotherapy.

  17. Gene targeting associated with the radiation sensitivity in squamous cell carcinoma by using microarray analysis

    International Nuclear Information System (INIS)

    Nimura, Yoshinori; Kumagai, Ken; Kouzu, Yoshinao; Higo, Morihiro; Kato, Yoshikuni; Seki, Naohiko; Yamada, Shigeru

    2005-01-01

    In order to identify a set of genes related to radiation sensitivity of squamous cell carcinoma (SCC) and establish a predictive method, we compared expression profiles of radio-sensitive/radio-resistant SCC cell lines, using the in-house cDNA microarray consisting of 2,201 human genes derived from full-length enriched SCC cDNA libraries and the Human oligo chip 30 K (Hitachi Software Engineering). Surviving fractions (SF) after irradiation of heavy iron were calculated by colony formation assay. Three pairs (TE2-TE13, YES5-YES6, and HSC3-HSC2), sensitive (SF1 0.6), were selected for the microarray analysis. The results of cDNA microarray analysis showed that 20 genes in resistant cell lines and 5 genes in sensitive cell lines were up regulated more than 1.5-fold compared with sensitive and resistant cell lines respectively. Fourteen out of 25 genes were confirmed the gene expression profiles by real-time polymerase chain reaction (PCR). Twenty-seven genes identified by Human oligo chip 30 K are candidate for the markers to distinguish radio-sensitive from radio-resistant. These results suggest that the isolated 27 genes are the candidates that might be used as specific molecular markers to predict radiation sensitivity. (author)

  18. Sensitivity to UV radiation in early life stages of the Mediterranean sea urchin Sphaerechinus granularis (Lamarck)

    Energy Technology Data Exchange (ETDEWEB)

    Nahon, Sarah [UPMC Univ Paris 06, UMR 7621, LOBB, Observatoire Oceanologique, F-66651, Banyuls/mer (France); CNRS, UMR 7621, LOBB, Observatoire Oceanologique, F-66651, Banyuls/mer (France); Castro Porras, Viviana A. [UPMC Univ Paris 06, UMR 7621, LOBB, Observatoire Oceanologique, F-66651, Banyuls/mer (France); Pruski, Audrey M. [UPMC Univ Paris 06, UMR 7621, LOBB, Observatoire Oceanologique, F-66651, Banyuls/mer (France); CNRS, UMR 7621, LOBB, Observatoire Oceanologique, F-66651, Banyuls/mer (France); Charles, Francois [UPMC Univ Paris 06, UMR 7621, LOBB, Observatoire Oceanologique, F-66651, Banyuls/mer (France); CNRS, UMR 7621, LOBB, Observatoire Oceanologique, F-66651, Banyuls/mer (France)], E-mail: charles@obs-banyuls.fr

    2009-03-01

    The sea urchin Sphaerechinus granularis was used to investigate the impact of relevant levels of UV-B radiation on the early life stages of a common Mediterranean free spawning benthic species. Sperm, eggs and embryos were exposed to a range of UV radiation doses. The resulting endpoints were evaluated in terms of fertilisation success, development and survival rates. Above a weighted UV radiation dose of 0.0029 kJ m{sup -2}, fertilisation capability of irradiated sperm decreased rapidly. The exposure of the eggs to 0.0175 kJ m{sup -2} and more led to delayed and inhibited development with ensuing embryonic morphological abnormalities. One-day old larvae remained strongly sensitive to UV radiation as shown by the 50% decrease of the larval survival rate for a dose of 0.025 kJ m{sup -2} UVR. The elevated sensitivity of embryos to experimental UVR went along with a lack of significant amount of sunscreen compounds (e.g., mycosporine-like amino acids) in the eggs. The present results demonstrated that gamete viability and embryonic development may be significantly impaired by solar UV radiation in S. granularis, compromising in this way the reproduction of the species. Unless adaptive behavioural reproductive strategies exist, the influence of ambient UV radiation appears as a selective force for population dynamics of broadcast spawners in the shallow benthic Mediterranean environment.

  19. Sensitivity to UV radiation in early life stages of the Mediterranean sea urchin Sphaerechinus granularis (Lamarck)

    International Nuclear Information System (INIS)

    Nahon, Sarah; Castro Porras, Viviana A.; Pruski, Audrey M.; Charles, Francois

    2009-01-01

    The sea urchin Sphaerechinus granularis was used to investigate the impact of relevant levels of UV-B radiation on the early life stages of a common Mediterranean free spawning benthic species. Sperm, eggs and embryos were exposed to a range of UV radiation doses. The resulting endpoints were evaluated in terms of fertilisation success, development and survival rates. Above a weighted UV radiation dose of 0.0029 kJ m -2 , fertilisation capability of irradiated sperm decreased rapidly. The exposure of the eggs to 0.0175 kJ m -2 and more led to delayed and inhibited development with ensuing embryonic morphological abnormalities. One-day old larvae remained strongly sensitive to UV radiation as shown by the 50% decrease of the larval survival rate for a dose of 0.025 kJ m -2 UVR. The elevated sensitivity of embryos to experimental UVR went along with a lack of significant amount of sunscreen compounds (e.g., mycosporine-like amino acids) in the eggs. The present results demonstrated that gamete viability and embryonic development may be significantly impaired by solar UV radiation in S. granularis, compromising in this way the reproduction of the species. Unless adaptive behavioural reproductive strategies exist, the influence of ambient UV radiation appears as a selective force for population dynamics of broadcast spawners in the shallow benthic Mediterranean environment

  20. Radiation-induced increases in sensitivity of cataleptic behavior to haloperidol: possible involvement of prostaglandins

    International Nuclear Information System (INIS)

    Joseph, J.A.; Kandasamy, S.B.; Hunt, W.A.; Dalton, T.K.; Stevens, S.

    1988-01-01

    The effects of radiation exposure on haloperidol-induced catalepsy were examined in order to determine whether elevated prostaglandins, through an action on dopaminergic autoreceptors, could be involved in the radiation-induced increase in the potency of this neuroleptic. Cataleptic behavior was examined in animals irradiated with various doses of gamma photons (1-150 Gy) and pretreated with a subthreshold dose of haloperidol (0.1 mg/kg). This approach was chosen to maximize any synergistic effects of radiation and haloperidol. After irradiation with doses less than or equal to 30 Gy, the combined treatment of haloperidol and radiation produced catalepsy, whereas neither treatment alone had an effect. This observed catalepsy could be blocked with prior administration of indomethacin, a prostaglandin synthesis inhibitor. Animals exposed to doses of radiation less than or equal to 50 Gy and no haloperidol, however, displayed apparent catalepsy. This effect was also antagonized by indomethacin. Prostaglandins can induce catalepsy and when administered in subthreshold doses along with subthreshold doses of haloperidol, catalepsy was observed. In order to assess a possible action of prostaglandins and radiation on dopaminergic activity, the functioning of striatal dopaminergic autoreceptors was examined by determining the effects of varying concentrations of haloperidol on the K+-evoked release of dopamine from striatal slices obtained from parallel groups of animals treated as above. Results indicated that sensitivity to haloperidol increased (higher K+-evoked dopamine release) in slices from irradiated or prostaglandin-treated animals and that this increase in sensitivity was blocked by indomethacin

  1. High level radiation dosimetry in biomedical research

    International Nuclear Information System (INIS)

    Inada, Tetsuo

    1979-01-01

    The physical and biological dosimetries relating to cancer therapy with radiation were taken up at the first place in the late intercomparison on high LET radiation therapy in Japan-US cancer research cooperative study. The biological dosimetry, the large dose in biomedical research, the high dose rate in biomedical research and the practical dosimeters for pulsed neutrons or protons are outlined with the main development history and the characteristics which were obtained in the relating experiments. The clinical neutron facilities in the US and Japan involved in the intercomparison are presented. Concerning the experimental results of dosimeters, the relation between the R.B.E. compared with Chiba (Cyclotron in National Institute of Radiological Sciences) and the energy of deuterons or protons used for neutron production, the survival curves of three cultured cell lines derived from human cancers, after the irradiation of 250 keV X-ray, cyclotron neutrons of about 13 MeV and Van de Graaff neutrons of about 2 MeV, the hatchability of dry Artemia eggs at the several depths in an absorber stack irradiated by 60 MeV proton beam of 40, 120 and 200 krad, the peak skin reaction of mouse legs observed at various sets of average and instantaneous dose rates, and the peak skin reaction versus three instantaneous dose rates at fixed average dose rate of 7,300 rad/min are shown. These actual data were evaluated numerically and in relation to the physical meaning from the viewpoint of the fundamental aspect of cancer therapy, comparing the Japanese measured values to the US data. The discussion record on the high dose rate effect of low LET particles on biological substances and others is added. (Nakai, Y.)

  2. Effects of peroxide and catalase on near ultraviolet radiation sensitivity in Escherichia coli strains

    Energy Technology Data Exchange (ETDEWEB)

    Coombs, A.M.L.; Moss, S.H.

    1987-03-01

    The role of peroxide and catalase on NUV radiation sensitivity was examined in two repair competent E. coli strains, AB1157 and B/r. Exponential phase B/r is considerably more sensitive to NUV radiation than exponential phase AB1157. However, resistance to 5 mmol dm/sup -3/ H/sub 2/O/sub 2/ was induced in both AB1157 and B/r by pretreating growing cells with 30 ..mu..mol dm/sup -3/ H/sub 2/O/sub 2/. Pretreatment also induced resistance to broad-band NUV radiation in these strains. The addition of catalase to the post-irradiation plating medium increased survival to the same extent as that provided by pretreatment with 30 ..mu..mol dm/sup -3/ H/sub 2/O/sub 2/, in both strains. The NUV radiation sensitivity seen in B/r does not appear to be due to a deficiency in enzymes that scavenge H/sub 2/O/sub 2/, as a catalase deficient mutant, E. coli UM1, is more resistant to NUV radiation than B/r. Also, assays for H/sub 2/O/sub 2/ scavenging ability show little difference between AB1157 and B/r in this respect. Two hypotheses are put forward to account for the sensitivity of exponential phase B/r. Whilst it is apparent that peroxides and catalase do have a role in NUV radiation damage, it is clear that other factors also influence survival under certain conditions.

  3. Radiation protection around high energy proton accelerators

    International Nuclear Information System (INIS)

    Bourgois, L.

    1996-01-01

    Proton accelerators are intense radiation sources because of the particle beam itself, secondary radiation and structure activation. So radiation protection is required around these equipment during running time but even during downtime. This article presents some estimated values about structure and air activation and applies the Moyer model to get dose rate behind shielding. (A.C.)

  4. High Temperature Radiators for Electric Propulsion Systems, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The VASIMR propulsion system uses a high temperature Loop Heat Pipe (LHP) radiator to reject heat from the helicon section. The current baseline radiator uses...

  5. High vulnerability of the developing brain to ionizing radiation

    International Nuclear Information System (INIS)

    Inouye, Minoru

    1991-01-01

    The developing mammalian brain is highly susceptible to environmental teratogenic insults, because of its long-lasting sensitive period extending from the beginning of embryonic organogenesis to the postnatal infantile period, the great vulnerability of undifferentiated neural cells to wide range of environmental agents including ionizing radiation, and the lack of further reproductive capacity of neurons. Disturbances in the production of neurons, and their migration to the cerebral and cerebellar cortices, give rise to malformations of the brain, such as an absent corpus callosum, disorganized cortical architecture, abnormal fissuring of the cerebral and cerebellar hemispheres, heterotopic cortical gray matter, ectopic cerebellar granule cells, microcephaly, etc. The critical developmental stage for the induction of histogenetic disorders of the cerebral cortex in humans is 8 weeks of pregnancy and following some weeks. This corresponds to day 13 of pregnancy for mice and day 15 for rats, i.e., the ventricular cells of fetal telencephalon are most susceptible to radiation-induced cell death in this stage of development. The lowest doses of X- and gamma-radiations which induce detectable biological effects in rats and mice are around 0.02 Gy in increasing acute cell death. Reduced brain weight and abnormal dendritic arborization are induced by 0.25 Gy and more. Histological abnormalities are produced by 0.5 Gy and more, and microcephaly and cerebellar malformations are by 1 Gy and more. (author)

  6. Achieving sensitive, high-resolution laser spectroscopy at CRIS

    Energy Technology Data Exchange (ETDEWEB)

    Groote, R. P. de [Instituut voor Kern- en Stralingsfysica, KU Leuven (Belgium); Lynch, K. M., E-mail: kara.marie.lynch@cern.ch [EP Department, CERN, ISOLDE (Switzerland); Wilkins, S. G. [The University of Manchester, School of Physics and Astronomy (United Kingdom); Collaboration: the CRIS collaboration

    2017-11-15

    The Collinear Resonance Ionization Spectroscopy (CRIS) experiment, located at the ISOLDE facility, has recently performed high-resolution laser spectroscopy, with linewidths down to 20 MHz. In this article, we present the modifications to the beam line and the newly-installed laser systems that have made sensitive, high-resolution measurements possible. Highlights of recent experimental campaigns are presented.

  7. Study of radiation sensitization of artesunate on human HeLa cells of cervical cancer

    International Nuclear Information System (INIS)

    Ji Rong; Cao Jianping; Chen Xialin; Zhu Wei; Jiang Qing; Pan Chunyan; Zhou Yuanyuan; Feng Yang; Peng Xiaomei; Liu Yang; Fan Saijun

    2010-01-01

    Objective: To investigate the radiosensitizing effects of artesunate on human HeLa cells of cervical cancer in vitro. Methods: Hela cells irradiated with 60 Co γ-rays. The dose rate was 0.635 Gy/min and the radiation dose was 0, 1, 2, 4, 6 Gy, respectively. The anti-proliferation activities of artesunate on HeLa cells were evaluated with MTT assay, to determine the most appropriate drug concentration. The effect of radiosensitivity was observed by using clonogenic assay. The single-hit multi-target model was used to plot the HeLa cell's dose-survival curve, to calculate mean lethal dose, quasi-threshold dose and sensitization enhancement rate, and to evaluate its radiosensitization effect. The apoptosis was analyzed with flow cytometry (FCM) to further test the radiation sensitization of artesunate on HeLa cells. Results: The inhibition of artesunate on HeLa cells increased with concentration. In radiation group, the cell cloning efficiency were 91.67%, 82.02%, 58.06%, 25.01%, respectively, and in artesunate (2.0 μmol/L) + radiation group, the cell cloning efficiency were 74.93%, 60.53%, 22.38%, 5.05%. In radiation group and artesunate (2.0 μmol/L) + radiation group, the mean lethal dose (D 0 ) was 2.95 and 2.07 Gy, respectively, while the qusai-threshold dose (D q ) were 2.01 and 1.24 Gy, respectively, and SER was 1.43. Compared with 2 and 6 Gy radiation group, the apoptosis rate of drug + radiation group increased from 12.26%, 40.08% to 22.71%, 59.92. Conclusions: The inhibiting effect of artesunate on HeLa cells is concentration-dependent. Artesunate has radiosensitizing effect on HeLa cells in vitro. (authors)

  8. Carboxymethyl starch cross-linked by electron beam radiation in presence of acrylic acid sensitizer

    International Nuclear Information System (INIS)

    Doan Binh; Nguyen Thanh Duoc; Pham Thi Thu Hong

    2013-01-01

    Carboxymethyl starch (CMS) can be cross-linked by electron beam radiation to form a biocompatible and environment-friendly hydrogel at a high absorbed dose and a condensed CMS concentration. Acrylic acid (AAc) can be used as a sensitizer in order to reduce the absorbed doses to an acceptable certain level. At an absorbed dose of 3-4 kGy, the gel content of crosslinked CMS can be obtained about 50% with 5% (w/w) AAc concentration used. The compressive strength of CMS samples increased with increasing their cross-linked densities due to raising absorbed doses. The swelling ratio of cross-linked CMS was also attainable at a maximum of 50 times in the distilled water. The enzymatic degradation of cross-linked CMS was carried out in acetate buffer pH 4.6 with 0.1% α-amylase enzymatic solution incubated at 40℃ for 6 h. The crosslinked CMS samples were degraded slower than uncrosslinked CMS ones. The results indicated that the highly cross-linked CMS was almost fully degradable when the enzymatic hydrolysis was performed during 6 h. The FT IR spectra of cross-linked CMS in the presence of AAc were examined to observe the carboxyl group of AAc in the structure of cross-linked CMS. The hydrophilic of cross-linked CMS surface was determined by a contact-angle analysis. (authors)

  9. Adaptive response to high LET radiations

    International Nuclear Information System (INIS)

    Dam, Annamaria; Bogdandi, E. Noemi; Polonyi, Istvan; Sardy, M. Marta; Balashazy, Imre; Palfalvy, Jozsef

    2001-01-01

    The biological consequences of exposure to ionizing radiation include gene mutation, chromosome aberrations, cellular transformation and cell death. These effects are attributed to the DNA damaging effects of the irradiation resulting in irreversible changes during DNA replication or during the processing of the DNA damage by enzymatic repair processes. These repair processes could initiate some adaptive mechanisms in the cell, which could lead to radioadaptive response (RAR). Adaptive responses have typically been detected by exposing cells to a low radiation dose (1-50 mGy) and then challenging the cells with a higher dose of radiation (2-4 Gy) and comparing the outcome to that seen with the challenge dose only. For adaptive response to be seen the challenge dose must be delivered within 24 hour of the inducing dose. Radio-adaptation is extensively studied for low LET radiation. Nevertheless, few data are available for high LET radiation at very low doses and dose rate. Our study was aimed to investigate the radioadaptive response to low-dose neutron irradiation by detection of the genotoxic damage i.e.: hprt-mutant colonies induced. Altered protein synthesis was also studied to identify stress proteins may responsible for radio-adaptation. New alpha particle irradiator system was also built up to study the biological effects of low dose alpha irradiation. The experiments were carried out on monolayers of human melanoma and CHO (Chines Hamster Ovary) cells irradiated by neutrons produced in the biological irradiation channel of the Research Reactor of Budapest Neutron Center. Cells were exposed to 0.5-50 mGy neutron doses with dose rates of 1.59-10 mGy/min. The challenge doses of 2-4 Gy gamma rays were administrated within 1-48 hours after priming treatment. The induced mutants at hprt locus were selected by adding 6-thioguanine and allow to grow for 10 days for expression of the phenotype. The protein synthesis was studied by PAGE, the molecular mass of specific

  10. Development of high temperature, radiation hard detectors based on diamond

    Energy Technology Data Exchange (ETDEWEB)

    Metcalfe, Alex, E-mail: Alex.Metcalfe@brunel.ac.uk [Wolfson Centre for Materials Processing, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Fern, George R. [Wolfson Centre for Materials Processing, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Hobson, Peter R. [Centre for Sensors & Instrumentation, College of Engineering, Design and Physical Sciences, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Ireland, Terry; Salimian, Ali; Silver, Jack [Wolfson Centre for Materials Processing, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Smith, David R. [Centre for Sensors & Instrumentation, College of Engineering, Design and Physical Sciences, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Lefeuvre, Gwenaelle [Micron Semiconductor Ltd., Lancing BN15 8 SJ (United Kingdom); Saenger, Richard [Schlumberger Limited, 91240 Clamart (France)

    2017-02-11

    Single crystal CVD diamond has many desirable properties compared to current, well developed, detector materials; exceptional radiation, chemical and physical hardness, chemical inertness, low Z (close to human tissue, good for dosimetry), wide bandgap and an intrinsic pathway to fast neutron detection through the {sup 12}C(n,α){sup 9}Be reaction. However effective exploitation of these properties requires development of a suitable metallisation scheme to give stable contacts for high temperature applications. To best utilise available processing techniques to optimise sensor response through geometry and conversion media configurations, a reliable model is required. This must assess the performance in terms of spectral response and overall efficiency as a function of detector and converter geometry. The same is also required for proper interpretation of experimental data. Sensors have been fabricated with varying metallisation schemes indented to permit high temperature operation; Present test results indicate that viable fabrication schemes for high temperature contacts have been developed and present modelling results, supported by preliminary data from partners indicate simulations provide a useful representation of response. - Highlights: • Radiation sensors using diamond as the sensitive volume have been constructed. • Functionality of these sensors with minimal degradation has been confirmed at 100 °C. • Sensitisation to thermal neutrons by addition of conversion layers has been modelled. • Modelling suggests 4× efficiency improvements from 3d converter-substrate interfaces.

  11. Radiation studies on the microflora in a High-level radiation environment

    International Nuclear Information System (INIS)

    Zahiera, T.S.

    1988-01-01

    Radiation sensitivities of microflora in the air environment of the irradiation room of the 60 CO industrial irradiation facility of NCRRT was studied. The isolated microflora was identified to be the Gram positive micrococci, and the gram positive bacilli: coagulans and laterosporous. The study of the dose-survival counts dependence of the colonies showed the existance of the combination of at least two groups of micro-organisms with different sensitivities to radiation. The value of the radiation resistant group was found to be 2.2 10kGy. A method is presented to estimate the amount of each group in the initial culture. A study of the dependence of radiation lethality on the dose rate of radiation on the aerobic dry microbes showed no significant effect in the dose-rate range from 330 down to 44 Gy.min

  12. The optimal condition of performing MTT assay for the determination of radiation sensitivity

    International Nuclear Information System (INIS)

    Hong, Semie; Kim, Il Han

    2001-01-01

    The measurement of radiation survival using a clonogenic assay, the established standard, can be difficult and time consuming. In this study, We have used the MTT assay, based on the reduction of a tetrazolium salt to a purple formazan precipitate by living cells, as a substitution for clonogenic assay and have examined the optimal condition for performing this assay in determination of radiation sensitivity. Four human cancer cell lines - PCI-1, SNU-1066, NCI-H63O and RKO cells have been used. For each cell line, a clonogenic assay and a MTT assay using Premix WST-1 solution, which is one of the tetrazolium salts and does not require washing or solubilization of the precipitate were carried out after irradiation of 0, 2, 4, 6, 8, 10 Gy, For clonogenic assay, cells in 25 cm 2 flasks were irradiated after overnight incubation and the resultant colonies containing more than 50 cells were scored after culturing the cells for 10-14 days, For MTT assay, the relationship between absorbance and cell number, optimal seeding cell number, and optimal timing of assay was determined. Then, MTT assay was performed when the irradiated cells had regained exponential growth or when the non-irradiated cells had undergone four or more doubling times. There was minimal variation in the values gained from these two methods with the standard deviation generally less than 5%, and there were no statistically significant differences between two methods according to t-test in low radiation dose (below 6 Gy). The regression analyses showed high linear correlation with the R 2 value of 0.975-0.992 between data from the two different methods. The optimal cell numbers for MTT assay were found to be dependent on plating efficiency of used cell line. Less than 300 cells/well were appropriate for cells with high plating efficiency (more than 30%). For cells with low plating efficiency (less than 30%), 500 cells/well or more were appropriate for assay. The optimal time for MTT assay was alter 6

  13. A new sensitive technique for study of radiation effects in amino acids

    International Nuclear Information System (INIS)

    Thwaites, D.I.; Buchan, G.; Ettinger, K.V.; Mallard, J.R.; Takavar, A.

    1976-01-01

    A new technique for the study of radiation induced free radicals in amino acids based on their reactions when untrapped by dissolution in water is reported. The light emission or lyoluminescence response of various amino acids to gamma radiation ( 60 Co) measured 4 hr after irradiation are shown. The sensitivities vary over three orders of magnitude, but there is little or no correlation between the lyoluminescent response and the structural type of amino acid. Dose-reponse curves indicate that the useful range extends from a few krad to a few hundred krad. Methods of extending the lower limits are discussed. Storage of irradiated material over a period of 4 months at 20 0 C showed changes of the order of 10%. Exposure to daylight has no effect on the light yield of amino acids. It is stated that the lyoluminescence technique is more sensitive than ESR in detecting radiation effects in amino acids. Lyoluminescence of irradiated proteins, RNA and DNA, has been observed. It appears that the new method may be particularly useful in providing information on the nature and magnitude of direct radiation damage in biologically important compounds and find applications in radiation dosimetry. (U.K.)

  14. Radiation sensitivity and gene expression in Enchytraeus japonensis, a species of earth worm

    International Nuclear Information System (INIS)

    Kubota, Yoshihisa

    2011-01-01

    The importance of radiological protection of the environment based on scientific principles is gaining international recognition as environment issues garner more attention. Earthworm (annelids) is a ubiquitous soil invertebrate known to play an important role in the maintenance of the soil ecosystem and thus selected as one of 12 kinds of reference animals and plants by the ICRP. In the present study, radiation sensitivity and gene expression in a recently described terrestrial oligochaete, Enchytraeus japonensis (E. japonensis) were studied. E. japonensis worms were acutely irradiated at increasing doses of gamma radiation, and the number of worms after 30 days of radiation was examined. The dose effectively inhibiting 50% of proliferation was approximately 22 Gy, which was comparable to the dose required to elicit growth inhibition in other earthworm species. In order to seek other biological endpoints for more sensitive and/or quicker assessment of radiation effects, gene expression profiling in E. japonensis was also performed, and poly (ADP-ribose) polymerase I (PARP I) was identified as a radiation-responsive gene. PARP I transcript level increased dose-dependently. (author)

  15. Sensitivity analysis of numerical weather prediction radiative schemes to forecast direct solar radiation over Australia

    Science.gov (United States)

    Mukkavilli, S. K.; Kay, M. J.; Taylor, R.; Prasad, A. A.; Troccoli, A.

    2014-12-01

    The Australian Solar Energy Forecasting System (ASEFS) project requires forecasting timeframes which range from nowcasting to long-term forecasts (minutes to two years). As concentrating solar power (CSP) plant operators are one of the key stakeholders in the national energy market, research and development enhancements for direct normal irradiance (DNI) forecasts is a major subtask. This project involves comparing different radiative scheme codes to improve day ahead DNI forecasts on the national supercomputing infrastructure running mesoscale simulations on NOAA's Weather Research & Forecast (WRF) model. ASEFS also requires aerosol data fusion for improving accurate representation of spatio-temporally variable atmospheric aerosols to reduce DNI bias error in clear sky conditions over southern Queensland & New South Wales where solar power is vulnerable to uncertainities from frequent aerosol radiative events such as bush fires and desert dust. Initial results from thirteen years of Bureau of Meteorology's (BOM) deseasonalised DNI and MODIS NASA-Terra aerosol optical depth (AOD) anomalies demonstrated strong negative correlations in north and southeast Australia along with strong variability in AOD (~0.03-0.05). Radiative transfer schemes, DNI and AOD anomaly correlations will be discussed for the population and transmission grid centric regions where current and planned CSP plants dispatch electricity to capture peak prices in the market. Aerosol and solar irradiance datasets include satellite and ground based assimilations from the national BOM, regional aerosol researchers and agencies. The presentation will provide an overview of this ASEFS project task on WRF and results to date. The overall goal of this ASEFS subtask is to develop a hybrid numerical weather prediction (NWP) and statistical/machine learning multi-model ensemble strategy that meets future operational requirements of CSP plant operators.

  16. Development of an efficient process for radiation vulcanization of natural rubber latex using hydroperoxide with sensitizer

    International Nuclear Information System (INIS)

    Siri-upathum, C.; Sonsuk, M.

    1996-01-01

    An attempt was made to reduce irradiation dose for radiation vulcanization of natural rubber latex. A promising method was to partially crosslink the latex by radiation vulcanization using n-butyl acrylate (n-BA) as sensitizer and t-butyl hydroperoxide (BHPO) as a co-sensitizer followed by redox vulcanization using residual BHPO as an oxidant and either fructose or tetra ethylene penta mine as reducing agents. It was found that the irradiation dose was reduced to 4 kGy with 5 phr n-BA as sensitizer and 0.1 phr BHPO as co-sensitizer. Successive crosslinking to full vulcanization was done by redox vulcanization using either 4 phr fructose at 60 degree C for 3 hours of 0.4 phr tetra-ethylene penta mine at room temperature for 1 hour. The rubber films obtained had tensile strength of about 25 MPa, modulus 300% of 0.9 MPa and crosslink density of about 1.5 x 10 19 crosslink/cm 3 . It was noted that the rubber film from the co-vulcanization was the average value of the values obtained by radiation vulcanization and redox vulcanization

  17. Cytogenetic findings from inhabitants of different ages in high background radiation areas of Yangjiang

    International Nuclear Information System (INIS)

    Chen Deqing; Yao Suyan; Zhang Chaoyang

    1997-01-01

    Objective: To explore the relationship between high background radiation and injurious effect on inhabitants. Method: Peripheral blood samples were collected from the inhabitants of 10, 40, 55 and 70 years old in high background radiation areas (HBRA) of Yangjiang, Chromosome preparations were carried out with conventional whole-blood microculture. Results: The percentage of dicentric chromosome with fragments in inhabitants of HBRA was significantly higher than that in control areas (CA) (0.469% vs. 0.315%, P<0.01), and there was an increase in the aberration frequencies with age (or accumulated doses). Conclusion: Chromosome aberration is an extremely sensitive indicator of radiation damage and a good radio-biodosimeter

  18. Radioprotective effect of garlic extract on some bacterial strains with different radiation sensitivities

    International Nuclear Information System (INIS)

    Tawfik, Z.S.; Abushady, M.R.

    1992-01-01

    The radioprotective effect of garlic on four bacterial strains with different degrees of radiation sensitivities was investigated. The presence of garlic led to an increase in d-10 value of Ps. Aeruginosa, S. aureus and S. typhimurium by 160%, 50%, and 30% respectively. The protective efficiency of garlic against radiation was noticed to be proportional to its concentration in a given inoculum size. Garlic extract up to 180 micro liter per 10 8 inoculum size of B. cereus showed no protective effect. This fact was attributed to the existence of sulphur compounds in the given strain. Higher garlic concentrations appeared to affect the cloning efficiency of a given strain. 4fig., 2tab

  19. Mechanisms of UVB-resistance in rice: Cultivar differences in the sensitivity to UVB radiation in rice

    International Nuclear Information System (INIS)

    Hidema, J.

    2001-01-01

    In a study on the sensitivity to UVB radiation of rice cultivars of 5 Asian rice ecotypes, results showed that the rice cultivars widely varied in UVB sensitivity; among the Japanese rice cultivars, Sasanishiki was more resistant to UVB, while Norin 1 was less resistant; UV-sensitive Norin 1 was deficient in photorepair of cyclobutane pyrimidine dimers (UV-induced DNA damage), and the sensitivity to UVB radiation significantly correlated with deficient CPD photorepair; and that this deficiency in Norin 1 resulted from a functionally altered photolyase. The results suggest that photorepair capacity is a principal factor in determining UVB sensitivity in rice. The effects of supplemental UVB radiation on the growth and yield of Japanese rice cultivars under field conditions were also studied in Japan since 1993. The results indicate that supplemental UVB radiation had inhibitory effects on the growth and yield of rice. Furthermore, grain size was smaller with supplemental UVB radiation

  20. Retinal sensitivity and choroidal thickness in high myopia.

    Science.gov (United States)

    Zaben, Ahmad; Zapata, Miguel Á; Garcia-Arumi, Jose

    2015-03-01

    To estimate the association between choroidal thickness in the macular area and retinal sensitivity in eyes with high myopia. This investigation was a transversal study of patients with high myopia, all of whom had their retinal sensitivity measured with macular integrity assessment microperimetry. The choroidal thicknesses in the macular area were then measured by optical coherence tomography, and statistical correlations between their functionality and the anatomical structuralism, as assessed by both types of measurements, were analyzed. Ninety-six eyes from 77 patients with high myopia were studied. The patients had a mean age ± standard deviation of 38.9 ± 13.2 years, with spherical equivalent values ranging from -6.00 diopter to -20.00 diopter (8.74 ± 2.73 diopter). The mean central choroidal thickness was 159.00 ± 50.57. The mean choroidal thickness was directly correlated with sensitivity (r = 0.306; P = 0.004) and visual acuity but indirectly correlated with the spherical equivalent values and patient age. The mean sensitivity was not significantly correlated with the macular foveal thickness (r = -0.174; P = 0.101) or with the overall macular thickness (r = 0.103; P = 0.334); furthermore, the mean sensitivity was significantly correlated with visual acuity (r = 0.431; P < 0.001) and the spherical equivalent values (r = -0.306; P = 0.003). Retinal sensitivity in highly myopic eyes is directly correlated with choroidal thickness and does not seem to be associated with retinal thickness. Thus, in patients with high myopia, accurate measurements of choroidal thickness may provide more accurate information about this pathologic condition because choroidal thickness correlates to a greater degree with the functional parameters, patient age, and spherical equivalent values.

  1. High sensitivity phase retrieval method in grating-based x-ray phase contrast imaging

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Zhao; Gao, Kun; Chen, Jian; Wang, Dajiang; Wang, Shenghao; Chen, Heng; Bao, Yuan; Shao, Qigang; Wang, Zhili, E-mail: wangnsrl@ustc.edu.cn [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China); Zhang, Kai [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Zhu, Peiping; Wu, Ziyu, E-mail: wuzy@ustc.edu.cn [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China and Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2015-02-15

    Purpose: Grating-based x-ray phase contrast imaging is considered as one of the most promising techniques for future medical imaging. Many different methods have been developed to retrieve phase signal, among which the phase stepping (PS) method is widely used. However, further practical implementations are hindered, due to its complex scanning mode and high radiation dose. In contrast, the reverse projection (RP) method is a novel fast and low dose extraction approach. In this contribution, the authors present a quantitative analysis of the noise properties of the refraction signals retrieved by the two methods and compare their sensitivities. Methods: Using the error propagation formula, the authors analyze theoretically the signal-to-noise ratios (SNRs) of the refraction images retrieved by the two methods. Then, the sensitivities of the two extraction methods are compared under an identical exposure dose. Numerical experiments are performed to validate the theoretical results and provide some quantitative insight. Results: The SNRs of the two methods are both dependent on the system parameters, but in different ways. Comparison between their sensitivities reveals that for the refraction signal, the RP method possesses a higher sensitivity, especially in the case of high visibility and/or at the edge of the object. Conclusions: Compared with the PS method, the RP method has a superior sensitivity and provides refraction images with a higher SNR. Therefore, one can obtain highly sensitive refraction images in grating-based phase contrast imaging. This is very important for future preclinical and clinical implementations.

  2. High sensitivity phase retrieval method in grating-based x-ray phase contrast imaging

    International Nuclear Information System (INIS)

    Wu, Zhao; Gao, Kun; Chen, Jian; Wang, Dajiang; Wang, Shenghao; Chen, Heng; Bao, Yuan; Shao, Qigang; Wang, Zhili; Zhang, Kai; Zhu, Peiping; Wu, Ziyu

    2015-01-01

    Purpose: Grating-based x-ray phase contrast imaging is considered as one of the most promising techniques for future medical imaging. Many different methods have been developed to retrieve phase signal, among which the phase stepping (PS) method is widely used. However, further practical implementations are hindered, due to its complex scanning mode and high radiation dose. In contrast, the reverse projection (RP) method is a novel fast and low dose extraction approach. In this contribution, the authors present a quantitative analysis of the noise properties of the refraction signals retrieved by the two methods and compare their sensitivities. Methods: Using the error propagation formula, the authors analyze theoretically the signal-to-noise ratios (SNRs) of the refraction images retrieved by the two methods. Then, the sensitivities of the two extraction methods are compared under an identical exposure dose. Numerical experiments are performed to validate the theoretical results and provide some quantitative insight. Results: The SNRs of the two methods are both dependent on the system parameters, but in different ways. Comparison between their sensitivities reveals that for the refraction signal, the RP method possesses a higher sensitivity, especially in the case of high visibility and/or at the edge of the object. Conclusions: Compared with the PS method, the RP method has a superior sensitivity and provides refraction images with a higher SNR. Therefore, one can obtain highly sensitive refraction images in grating-based phase contrast imaging. This is very important for future preclinical and clinical implementations

  3. Thermal radiosensitization in heat- and radiation-sensitive mutants of CHO cells

    International Nuclear Information System (INIS)

    Kampinga, H.H.; Kanon, B.; Konings, A.W.T.; Stackhouse, M.A.; Bedford, J.S.

    1993-01-01

    In the current study, the extent of hyperthermic radiosensitization in a new γ-radiation-sensitive cell line, irs-20, recently isolated by Stackhouse and Bedford (1991) and a heat-sensitive mutant hs-36 (Harvey and Bedford 1988) was compared with the radiosensitization of their mutual parent CHO 10B12 cell line. The irs-20 and CHO 10B12 cells have comparable heat (43.5 o C) sensitivities, whereas hs-36 and CHO 10B12 show a similar sensitivity to γ- and X-rays. Radiosensitization due to pre-exposure to 43.5 o C heating of plateau phase cultures was found for all three cell lines, even after relatively mild heat treatment killing <20% of cells. Experiments using CHEF electrophoresis confirmed the dsb repair deficiency of the irs-20 cells (Stackhouse and Bedford 1992) and showed that heat inhibited dsb repair in all three cell lines. (Author)

  4. Radiation damage in a high Ni weld

    International Nuclear Information System (INIS)

    Brumovsky, M.; Kytka, M.; Kopriva, R.

    2015-01-01

    WWER-1000 RPV weld metals are characterized by a high content of nickel, mostly about 1.7 mass % with content of manganese around 0.8 mass % with a very low copper content - about 0.05 mass %. In such material some late blooming phase effect should be observed during irradiation. Such typical weld material was irradiated in the experimental reactor LVR-15 in N RI Rez at the irradiation temperature 290 C degrees and at five neutron fluences from 1.5 to 9.5 *10 23 m -2 (E>1 MeV). Charpy V-notch impact tests, static fracture toughness tests, tensile and hardness measurement were performed to obtain effect of neutron fluence on radiation hardening as well as embrittlement. Neutron fluence dependences of all these property changes have monotonic character but with a high neutron embrittlement exponent around 0.8. Scanning electron microscope of fracture surfaces showed no or very small portion of intercrystalline fracture. Transmission electron microscopy was performed on specimens from all neutron fluences. Only low density of black-dot damage has been observed. It is assumed that most of defect are dislocation loops. The late blooming phase which may be observed from results of mechanical properties are probably below the resolution of the used JEM-2010, i.e. 1.5 nm. (authors)

  5. High mortality of Red Sea zooplankton under ambient solar radiation.

    Science.gov (United States)

    Al-Aidaroos, Ali M; El-Sherbiny, Mohsen M O; Satheesh, Sathianeson; Mantha, Gopikrishna; Agustī, Susana; Carreja, Beatriz; Duarte, Carlos M

    2014-01-01

    High solar radiation along with extreme transparency leads to high penetration of solar radiation in the Red Sea, potentially harmful to biota inhabiting the upper water column, including zooplankton. Here we show, based on experimental assessments of solar radiation dose-mortality curves on eight common taxa, the mortality of zooplankton in the oligotrophic waters of the Red Sea to increase steeply with ambient levels of solar radiation in the Red Sea. Responses curves linking solar radiation doses with zooplankton mortality were evaluated by exposing organisms, enclosed in quartz bottles, allowing all the wavelengths of solar radiation to penetrate, to five different levels of ambient solar radiation (100%, 21.6%, 7.2%, 3.2% and 0% of solar radiation). The maximum mortality rates under ambient solar radiation levels averaged (±standard error of the mean, SEM) 18.4±5.8% h(-1), five-fold greater than the average mortality in the dark for the eight taxa tested. The UV-B radiation required for mortality rates to reach ½ of maximum values averaged (±SEM) 12±5.6 h(-1)% of incident UVB radiation, equivalent to the UV-B dose at 19.2±2.7 m depth in open coastal Red Sea waters. These results confirm that Red Sea zooplankton are highly vulnerable to ambient solar radiation, as a consequence of the combination of high incident radiation and high water transparency allowing deep penetration of damaging UV-B radiation. These results provide evidence of the significance of ambient solar radiation levels as a stressor of marine zooplankton communities in tropical, oligotrophic waters. Because the oligotrophic ocean extends across 70% of the ocean surface, solar radiation can be a globally-significant stressor for the ocean ecosystem, by constraining zooplankton use of the upper levels of the water column and, therefore, the efficiency of food transfer up the food web in the oligotrophic ocean.

  6. High mortality of Red Sea zooplankton under ambient solar radiation.

    Directory of Open Access Journals (Sweden)

    Ali M Al-Aidaroos

    Full Text Available High solar radiation along with extreme transparency leads to high penetration of solar radiation in the Red Sea, potentially harmful to biota inhabiting the upper water column, including zooplankton. Here we show, based on experimental assessments of solar radiation dose-mortality curves on eight common taxa, the mortality of zooplankton in the oligotrophic waters of the Red Sea to increase steeply with ambient levels of solar radiation in the Red Sea. Responses curves linking solar radiation doses with zooplankton mortality were evaluated by exposing organisms, enclosed in quartz bottles, allowing all the wavelengths of solar radiation to penetrate, to five different levels of ambient solar radiation (100%, 21.6%, 7.2%, 3.2% and 0% of solar radiation. The maximum mortality rates under ambient solar radiation levels averaged (±standard error of the mean, SEM 18.4±5.8% h(-1, five-fold greater than the average mortality in the dark for the eight taxa tested. The UV-B radiation required for mortality rates to reach ½ of maximum values averaged (±SEM 12±5.6 h(-1% of incident UVB radiation, equivalent to the UV-B dose at 19.2±2.7 m depth in open coastal Red Sea waters. These results confirm that Red Sea zooplankton are highly vulnerable to ambient solar radiation, as a consequence of the combination of high incident radiation and high water transparency allowing deep penetration of damaging UV-B radiation. These results provide evidence of the significance of ambient solar radiation levels as a stressor of marine zooplankton communities in tropical, oligotrophic waters. Because the oligotrophic ocean extends across 70% of the ocean surface, solar radiation can be a globally-significant stressor for the ocean ecosystem, by constraining zooplankton use of the upper levels of the water column and, therefore, the efficiency of food transfer up the food web in the oligotrophic ocean.

  7. Effect of Long Term Low-Level Gamma Radiation on Thermal Sensitivity of RDX/HMX Mixtures

    Science.gov (United States)

    1976-11-01

    1.1x10 R. It was concluded that the slight exothermic reaction before the 3^6 HMX polymorphic transition could be caused by a radiation-induced...Radiation on Thermal Sensitivity of RDX / HMX Mixtures 5. TYPE OF REPORT 4 PERIOD COVERED Final Report 6. PERFORMING ORG. REPORT NUMBER 7...and Identity by block number) Gamma radiation Weight loss HMX Impact sensitivity test RDX Vacuum stability test DTA Infrared spectrometry TGA

  8. Differences in the sensitivity to UVB radiation of two cultivars of rice (Oryza sativa L.)

    International Nuclear Information System (INIS)

    Hidema, J.; Kang, H.S.; Kumagai, T.

    1996-01-01

    The effects of UVB radiation on the growth of two cultivars of Japanese lowland rice (Oryza sativa L.), Sasanishiki and Norin 1, were examined in a phytotron. Supplementation of visible radiation with UVB radiation reduced plant length, tiller number, the fresh and dry weights of the aboveground parts of plants, an the amounts of total leaf nitrogen, chlorophyll, soluble protein and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) in the eight leaf, the youngest fully expanded leaf. By contrast, UVB radiation significantly increased the accumulation of UV-absorbing compounds. There was a difference between the two cultivars in the resistance to the effects of UVB radiation. The reduction in the amounts of Rubisco was smaller in Sasanishiki, while the increase in the accumulation of UV-absorbing compounds was greater in Sasanishiki. Parameters of plant growth, with the exception of the amount of Rubisco, decreased in direct proportion to decreases in total leaf nitrogen in plants grown under lower or the Rubisco content of Norin 1 grown under a high dose of UVB radiation was exceptionally marked, and was not observed similarly in Sasanishiki. The results suggest that the remarkable reduction in rubisco content in NOrin 1 might have been due to the specific effects of UVB radiation. It is also suggested that the difference between cultivars in the resistance to UVB radiation might be due to the differences in the levels of Rubisco and in UV-absorbing compounds that are induced by UVB radiation

  9. Amorphous chalcogenide semiconductors for solid state dosimetric systems of high-energetic ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, O. [Pedagogical University, Czestochowa (Poland)]|[Institute of Materials, Lvov (Ukraine)

    1997-12-31

    The application possibilities of amorphous chalcogenide semiconductors use as radiation-sensitive elements of high-energetic (E > 1 MeV) dosimetric systems are analysed. It is shown that investigated materials are characterized by more wide region of registered absorbed doses and low temperature threshold of radiation information bleaching in comparison with well-known analogies based on coloring oxide glasses. (author). 16 refs, 1 tab.

  10. Effects of high altitude clouds on the earth's infrared radiation flux

    Science.gov (United States)

    Wang, W.-C.; Kaplan, L. D.

    1983-01-01

    Attention is given to the results of a study of cirrus cloud properties which employed the Goddard Laboratory for Atmospheric Sciences' general circulation model and concentrated on the effects of the nonblackness of high clouds on the IR radiation flux. Although the thermal radiation flux is very sensitive to the treatment of cirrus optical properties in the IR, a more realistic assessment will depend on better parameterizations for cirrus cloud formation, persistence, and dissipation.

  11. BH3105 type neutron dose equivalent meter of high sensitivity

    International Nuclear Information System (INIS)

    Ji Changsong; Zhang Enshan; Yang Jianfeng; Zhang Hong; Huang Jiling

    1995-10-01

    It is noted that to design a neutron dose meter of high sensitivity is almost impossible in the frame of traditional designing principle--'absorption net principle'. Based on a newly proposed principle of obtaining neutron dose equi-biological effect adjustment--' absorption stick principle', a brand-new neutron dose-equivalent meter with high neutron sensitivity BH3105 has been developed. Its sensitivity reaches 10 cps/(μSv·h -1 ), which is 18∼40 times higher than one of foreign products of the same kind and is 10 4 times higher than that of domestic FJ342 neutron rem-meter. BH3105 has a measurement range from 0.1μSv/h to 1 Sv/h which is 1 or 2 orders wider than that of the other's. It has the advanced properties of gamma-resistance, energy response, orientation, etc. (6 tabs., 5 figs.)

  12. A high sensitivity nanomaterial based SAW humidity sensor

    Energy Technology Data Exchange (ETDEWEB)

    Wu, T-T; Chou, T-H [Institute of Applied Mechanics, National Taiwan University, Taipei 106, Taiwan (China); Chen, Y-Y [Department of Mechanical Engineering, Tatung University, Taipei 104, Taiwan (China)], E-mail: wutt@ndt.iam.ntu.edu.tw

    2008-04-21

    In this paper, a highly sensitive humidity sensor is reported. The humidity sensor is configured by a 128{sup 0}YX-LiNbO{sub 3} based surface acoustic wave (SAW) resonator whose operating frequency is at 145 MHz. A dual delay line configuration is realized to eliminate external temperature fluctuations. Moreover, for nanostructured materials possessing high surface-to-volume ratio, large penetration depth and fast charge diffusion rate, camphor sulfonic acid doped polyaniline (PANI) nanofibres are synthesized by the interfacial polymerization method and further deposited on the SAW resonator as selective coating to enhance sensitivity. The humidity sensor is used to measure various relative humidities in the range 5-90% at room temperature. Results show that the PANI nanofibre based SAW humidity sensor exhibits excellent sensitivity and short-term repeatability.

  13. Performance of terahertz metamaterials as high-sensitivity sensor

    Science.gov (United States)

    He, Yanan; Zhang, Bo; Shen, Jingling

    2017-09-01

    A high-sensitivity sensor based on the resonant transmission characteristics of terahertz (THz) metamaterials was investigated, with the proposal and fabrication of rectangular bar arrays of THz metamaterials exhibiting a period of 180 μm on a 25 μm thick flexible polyimide. Varying the size of the metamaterial structure revealed that the length of the rectangular unit modulated the resonant frequency, which was verified by both experiment and simulation. The sensing characteristics upon varying the surrounding media in the sample were tested by simulation and experiment. Changing the surrounding medium from that of air to that of alcohol or oil produced resonant frequency redshifts of 80 GHz or 150 GHz, respectively, which indicates that the sensor possessed a high sensitivity of 667 GHz per unit of refractive index. Finally, the influence of the sample substrate thickness on the sensor sensitivity was investigated by simulation. It may be a reference for future sensor design.

  14. Preliminary Study of Position-Sensitive Large-Area Radiation Portal Monitor

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Chang Hwy; Kim, Hyunok; Moon, Myung Kook [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Jongyul [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Park, Jong Won; Lim, Yong Kon [Korea Institute of Ocean Science and Technology, Daejeon (Korea, Republic of)

    2013-10-15

    An RPM, which is a passive inspection method, is a system for monitoring the movement of radioactive materials at an airport, seaport, border, etc. To detect a γ-ray, an RPM using the plastic scintillator is generally used. The method of γ-ray detection using an RPM with a plastic scintillator is to measure lights generated by an incident γ-ray in the scintillator. Generally, a large-area RPM uses one or two photomultiplier tubes (PMT) for light collection. However, in this study, we developed a 4-ch RPM that can measure the radiation signal using 4 PMTs. The reason for using 4 PMTs is to calculate the position of the radiation source. In addition, we developed an electric device for acquisition of a 4-ch output signal at the same time. To estimate the performance of the developed RPM, we performed an RPM test using a {sup 60}Co γ-ray check source. In this study, we performed the development of a 4-ch RPM. The major function of the typical RPM is to measure the radiation. However, we developed a position-sensitive 4-ch RPM, which can be used to measure the location of the radiation source, as well as the radiation measurement, at the same time. In the future, we plan to develop an algorithm for a position detection of the radiation. In addition, an algorithm will be applied to an RPM.

  15. Biochemical reasoning for radiation protection and screening methods for radiation sensitivity and potential carcinogenicity

    International Nuclear Information System (INIS)

    Riklis, Emanuel; Emerit, Ingrid

    1994-01-01

    Cells of different genetic characteristics respond differently to agents that modify radiation effects. When the modification is a result of chemical repair, reduction of the amount of damage by radical scavenging, production of hypoxia, or any other such mechanism, then the modification of the response will be the same for all types of cells, but not the same when biological or biochemical parameters are involved, because the differences between the cells affect the final outcome, and the genetic traits obviously become affected by chemical modifying agents. Some of these agents directly affect the repair of deoxyribonucleic acid (DNA) by mechanisms not yet understood. Another agent nicotinamide (NA), is directly linked to a repair pathway. Thus, a system that uses NA as a precursor of nicotinamide adenine dinucleotide (NAD) + , and uses NAD + to produce the polymer polyadenosine diphosphate ribose (PADPR) appears to be an interesting and important factor in the biochemical events that may be linked to improved radioprotection. (author). 36 refs., 5 figs

  16. Evaluation of phase sensitive detection method and Si avalanche photodiode for radiation thermometry

    International Nuclear Information System (INIS)

    Hobbs, M J; Tan, C H; Willmott, J R

    2013-01-01

    We report the evaluation of Si avalanche photodiodes (APDs) for use in radiation thermometry as an alternative to Si photodiodes. We compared their performance when operated under phase sensitive detection (PSD), where the signal is modulated, and direct detection (DD) methods. A Si APD was compared with a Si photodiode with reference black body temperatures of 275 to 600°C, in terms of the mean output voltage and signal-to-noise ratio (SNR), measured at different APD gain values. We found that using both PSD and DD methods, the high internal gain of the Si APD achieved a lower minimum detection temperature in order to satisfy a specific minimum output voltage of the detector-preamplifier combination employed. The use of PSD over DD for the Si APD allowed for improved performance of the thermometer, with a lower minimum measurable temperature, as well as improvement in the SNR. For instance we found that at 350°C, the Si APD biased at 150 V using PSD can provide ∼ 88 times enhancement in the system SNR over that of a Si photodiode using DD. A corresponding temperature error of ±0.05°C was achieved using the APD with PSD compared to an error of ±2.75°C measured using the Si photodiode with DD.

  17. Effect of genes controlling radiation sensitivity on chemically induced mutations in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Prakash, L.

    1976-01-01

    The effect of 16 different genes (rad) conferring radiation sensitivity on chemically induced reversion in the yeast Saccharomyces cerevisiae was determined. The site of reversion used was a well-defined chain initiation mutant mapping in the structural gene coding for iso-1-cytochrome c. High doses of EMS and HNO 2 resulted in decreased reversion of cyc1-131 in rad6, rad9 and rad15 strains compared to the normal RAD + strains. In addition, rad52 greatly decreased EMS reversion of cyc1-131 but had no effect on HNO 2 -induced reversion; rad18, on the other hand, increased HNO 2 -induced reversion but did not alter EMS-induced reversion. When NQO was used as the mutagen, every rad gene tested, except for rad18, had an effect on reversion; rad6, rad9, rad15, rad17, rad18, rad22, rev1, rev2, and rev3 lowered NQO reversion while rad1, rad2, rad3, rad4, rad10, rad12, and rad16 increased it compared to the RAD + strain. The effect of rad genes on chemical mutagenesis is discussed in terms of their effect on uv mutagenesis. It is concluded that although the nature of the repair pathways may differ for uv- and chemically-induced mutations in yeast, a functional repair system is required for the induction of mutation by the chemical agents NQO, EMS, and HNO 2

  18. Sensitive high performance liquid chromatographic method for the ...

    African Journals Online (AJOL)

    A new simple, sensitive, cost-effective and reproducible high performance liquid chromatographic (HPLC) method for the determination of proguanil (PG) and its metabolites, cycloguanil (CG) and 4-chlorophenylbiguanide (4-CPB) in urine and plasma is described. The extraction procedure is a simple three-step process ...

  19. Methylation-Sensitive High Resolution Melting (MS-HRM).

    Science.gov (United States)

    Hussmann, Dianna; Hansen, Lise Lotte

    2018-01-01

    Methylation-Sensitive High Resolution Melting (MS-HRM) is an in-tube, PCR-based method to detect methylation levels at specific loci of interest. A unique primer design facilitates a high sensitivity of the assays enabling detection of down to 0.1-1% methylated alleles in an unmethylated background.Primers for MS-HRM assays are designed to be complementary to the methylated allele, and a specific annealing temperature enables these primers to anneal both to the methylated and the unmethylated alleles thereby increasing the sensitivity of the assays. Bisulfite treatment of the DNA prior to performing MS-HRM ensures a different base composition between methylated and unmethylated DNA, which is used to separate the resulting amplicons by high resolution melting.The high sensitivity of MS-HRM has proven useful for detecting cancer biomarkers in a noninvasive manner in urine from bladder cancer patients, in stool from colorectal cancer patients, and in buccal mucosa from breast cancer patients. MS-HRM is a fast method to diagnose imprinted diseases and to clinically validate results from whole-epigenome studies. The ability to detect few copies of methylated DNA makes MS-HRM a key player in the quest for establishing links between environmental exposure, epigenetic changes, and disease.

  20. Aluminum nano-cantilevers for high sensitivity mass sensors

    DEFF Research Database (Denmark)

    Davis, Zachary James; Boisen, Anja

    2005-01-01

    We have fabricated Al nano-cantilevers using a very simple one mask contact UV lithography technique with lateral dimensions under 500 nm and vertical dimensions of approximately 100 nm. These devices are demonstrated as highly sensitive mass sensors by measuring their dynamic properties. Further...

  1. High sensitivity probe absorption technique for time-of-flight ...

    Indian Academy of Sciences (India)

    Abstract. We report on a phase-sensitive probe absorption technique with high sen- sitivity, capable of detecting a few hundred ultra-cold atoms in flight in an observation time of a few milliseconds. The large signal-to-noise ratio achieved is sufficient for reliable measurements on low intensity beams of cold atoms.

  2. Radiation sensitivity and DNA repair in Caenorhabditis elegans strains with different mean life spans

    Energy Technology Data Exchange (ETDEWEB)

    Hartman, P S; Simpson, V J; Johnson, T; Mitchell, D

    1988-06-01

    The sensitivities to three DNA damaging agents (UV and ..gamma..-radiation, methyl methanesulfonate) were measured in four recombinant inbred (RI) strains of Caenorhabditis elegans with mean life spans ranging from 13 to 30.9 days, as well as in the wild-type strains used to derive these RI's. Sensitivities at several stages in the developmental cycle were tested. There were no significant correlations between mean life span and the lethal effects of these 3 agents. Excision of two UV-radiation-induced DNA photoproducts was also measured. Long-lived strains were no more repair competent than shorter-lived strains. These data indicate that DNA repair plays at best a minor role in the aging process of C. elegans. 33 refs.; 4 figs.

  3. Sensitivity of pathogenic and free-living Leptospira spp. to UV radiation and mitomycin C

    International Nuclear Information System (INIS)

    Stamm, L.V.; Charon, N.W.

    1988-01-01

    The habitats for the two major Leptospira spp. differ. The main habitat of L. biflexa is soil and water, whereas L. interrogans primarily resides in the renal tubules of animals. We investigated whether these two species, along with L. illini (species incertae sedis), differ with respect to their sensitivity to UV radiation. The doses of UV resulting in 37, 10 and 1% survival were determined for representive serovars from each species. L. interrogans serovar pomona was 3.0 to 4.8 times more sensitive to UV than the other Leptospira species under the 37, 10, and 1% survival parameters. In comparison to other bacteria, L. interrogans serovar pomona is among the most sensitive to UV. In a qualitative UV sensitivity assay., L. interrogans serovars were found to be in general more sensitive than L. biflexa serovars. All three species were found to have a photoreactivation DNA repair mechanism. Since organisms that are resistant to UV are often resistant to the DNA cross-linking agent mitomycin C, we tested the relative sensitivity of several Leptospira serovars to this compound. With few exceptions, L. biflexa and L. illini serovars were considerably more resistant to mitomycin C than the L. interrogans serovars. The mitomycin C sensitivity assay could be a useful addition to current characterization tests used to differentiate the Leptospira species

  4. Sensitivity of pathogenic and free-living Leptospira spp. to UV radiation and mitomycin C

    Energy Technology Data Exchange (ETDEWEB)

    Stamm, L.V.; Charon, N.W.

    1988-03-01

    The habitats for the two major Leptospira spp. differ. The main habitat of L. biflexa is soil and water, whereas L. interrogans primarily resides in the renal tubules of animals. We investigated whether these two species, along with L. illini (species incertae sedis), differ with respect to their sensitivity to UV radiation. The doses of UV resulting in 37, 10 and 1% survival were determined for representive serovars from each species. L. interrogans serovar pomona was 3.0 to 4.8 times more sensitive to UV than the other Leptospira species under the 37, 10, and 1% survival parameters. In comparison to other bacteria, L. interrogans serovar pomona is among the most sensitive to UV. In a qualitative UV sensitivity assay., L. interrogans serovars were found to be in general more sensitive than L. biflexa serovars. All three species were found to have a photoreactivation DNA repair mechanism. Since organisms that are resistant to UV are often resistant to the DNA cross-linking agent mitomycin C, we tested the relative sensitivity of several Leptospira serovars to this compound. With few exceptions, L. biflexa and L. illini serovars were considerably more resistant to mitomycin C than the L. interrogans serovars. The mitomycin C sensitivity assay could be a useful addition to current characterization tests used to differentiate the Leptospira species.

  5. MicroRNA-203 Modulates the Radiation Sensitivity of Human Malignant Glioma Cells

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Ji Hyun [Department of Radiation Oncology, Graduate School of Medicine, Seoul National University, Seoul (Korea, Republic of); Hwang, Yeo Hyun; Lee, David J.; Kim, Dan Hyo; Park, Ji Min [Medical Science Research Institute, Seoul National University Bundang Hospital, Kyeonggido (Korea, Republic of); Wu, Hong-Gyun [Department of Radiation Oncology, Graduate School of Medicine, Seoul National University, Seoul (Korea, Republic of); Kim, In Ah, E-mail: inah228@snu.ac.kr [Department of Radiation Oncology, Graduate School of Medicine, Seoul National University, Seoul (Korea, Republic of); Medical Science Research Institute, Seoul National University Bundang Hospital, Kyeonggido (Korea, Republic of); Cancer Research Institute, Seoul National University, Seoul (Korea, Republic of)

    2016-02-01

    Purpose: We investigated whether miR-203 could modulate the radiation sensitivity of glioblastoma (GBM) cells and which target gene(s) could be involved. Methods and Materials: Three human malignant glioma (MG) cell lines and normal human astrocytes were transfected with control microRNA, pre-miR-203, or antisense miR-203. Real-time PCR (RT-PCR), clonogenic assays, immunofluorescence, and invasion/migration assays were performed. To predict the target(s), bioinformatics analyses using microRNA target databases were performed. Results: Overexpression of miR-203 increased the radiation sensitivity of all 3 human MG cell lines and prolonged radiation-induced γ-H2AX foci formation. Bioinformatics analyses suggested that miR-203 could be involved in post-transcriptional control of DNA repair, PI3K/AKT, SRC, and JAK/STAT3 and the vascular signaling pathway. Western blot analysis validated the fact that miR-203 downregulated ATM, RAD51, SRC, PLD2, PI3K-AKT, JAK-STAT3, VEGF, HIF-1α, and MMP2. Overexpression of miR-203 inhibited invasion and migration potentials, downregulated SLUG and Vimentin, and upregulated Claudin-1 and ZO1. Conclusions: These data demonstrate that miR-203 potentially controls DNA damage repair via the PI3K/AKT and JAK/STAT3 pathways and may collectively contribute to the modulation of radiation sensitivity in MG cells by inhibiting DNA damage repair, prosurvival signaling, and epithelium-mesenchyme transition. Taken together, these findings demonstrate that miR-203 could be a target for overcoming the radiation resistance of GBM.

  6. MicroRNA-203 Modulates the Radiation Sensitivity of Human Malignant Glioma Cells

    International Nuclear Information System (INIS)

    Chang, Ji Hyun; Hwang, Yeo Hyun; Lee, David J.; Kim, Dan Hyo; Park, Ji Min; Wu, Hong-Gyun; Kim, In Ah

    2016-01-01

    Purpose: We investigated whether miR-203 could modulate the radiation sensitivity of glioblastoma (GBM) cells and which target gene(s) could be involved. Methods and Materials: Three human malignant glioma (MG) cell lines and normal human astrocytes were transfected with control microRNA, pre-miR-203, or antisense miR-203. Real-time PCR (RT-PCR), clonogenic assays, immunofluorescence, and invasion/migration assays were performed. To predict the target(s), bioinformatics analyses using microRNA target databases were performed. Results: Overexpression of miR-203 increased the radiation sensitivity of all 3 human MG cell lines and prolonged radiation-induced γ-H2AX foci formation. Bioinformatics analyses suggested that miR-203 could be involved in post-transcriptional control of DNA repair, PI3K/AKT, SRC, and JAK/STAT3 and the vascular signaling pathway. Western blot analysis validated the fact that miR-203 downregulated ATM, RAD51, SRC, PLD2, PI3K-AKT, JAK-STAT3, VEGF, HIF-1α, and MMP2. Overexpression of miR-203 inhibited invasion and migration potentials, downregulated SLUG and Vimentin, and upregulated Claudin-1 and ZO1. Conclusions: These data demonstrate that miR-203 potentially controls DNA damage repair via the PI3K/AKT and JAK/STAT3 pathways and may collectively contribute to the modulation of radiation sensitivity in MG cells by inhibiting DNA damage repair, prosurvival signaling, and epithelium-mesenchyme transition. Taken together, these findings demonstrate that miR-203 could be a target for overcoming the radiation resistance of GBM.

  7. Development of rubber material for high radiation field

    International Nuclear Information System (INIS)

    Nakatsukasa, Sadayoshi; Tabasaki, Takeshi; Yoshida, Akihiro; Kadowaki, Yoshito

    2013-01-01

    Generally flexible polymeric materials exposed to radiation can't be used because they soften or harden remarkably in high radiation environment. Aromatic polymers such as PEEK, PI, and PES are also known as radiation-proof polymeric materials. Aromatic polymers are very hard, they can't be used for products like a packing where flexibility is required. We developed a new vulcanized rubber compound by the use of various additives and polymer blend. This developed rubber compound has a high radiation-proof performance by reaction balance of cross-linking and decomposition in this rubber. This rubber compound has a rubber elasticity even if exposed to radiation of MGy level, and its radiation proof is more than 5 times as high as conventional polymeric materials. This rubber compound is much more flexible than the aromatic polymers which are the used as conventional radiation-proof polymers. (author)

  8. Radiation sensitivity of fibroblast strains from patients with Usher's syndrome, Duchenne muscular dystrophy, and Huntington's disease

    International Nuclear Information System (INIS)

    Nove, J.; Little, J.B.; Tarone, R.E.; Robbins, J.H.

    1987-01-01

    The colony-forming ability of 10 normal human fibroblast cell strains and of 10 strains representing 3 degenerative diseases of either nerve or muscle cells was determined after exposure of the cells to X-rays or β-particles from tritiated water. Both methods of irradiation yielded similar comparative results. The fibroblast strains from the 5 Usher's syndrome patients and from 1 of the 2 Huntington's disease patients were hypersensitive to radiation, while those from the 3 Duchenne muscular dystrophy patients and the second Huntington's disease patient had normal sensitivity to radiation. These results indicate both disease-specific and strain-specific differences in the survival of fibroblasts after exposure to ionizing radiation. 38 refs.; 2 figs.; 3 tabs

  9. Genetic analysis of gamma-ray mutagenesis in yeast. I. Reversion in radiation-sensitive strains

    International Nuclear Information System (INIS)

    McKee, R.H.; Lawrence, C.W.

    1979-01-01

    The frequency of revertants induced by 60 Co γ rays of the ochre allele, cyc1-9, has been measured in radiation-sensitive strains carrying one of 19 nonallelic mutations and in wild-type strains. The results indicate that ionizing radiation mutagenesis depends on the activity of the RAD6 group of genes and that the gene functions employed are very similar, but probably not identical, to those that mediate uv mutagenesis. Repair activities dependent on the functions of the RAD50 through RAD57 loci, the major pathway for the repair of damage caused by ionizing radiation, do not appear to play any part in mutagenesis. A comparison between the γ-ray data and those obtained previously with uv and chemical mutagens suggests that the RAD6 mutagenic pathway is in fact composed of a set of processes, some of which are concerned with error-prone, and some with error-free, recovery activities

  10. Experimental study of variations in background radiation and the effect on Nuclear Car Wash sensitivity

    International Nuclear Information System (INIS)

    Church, J; Slaughter, D; Norman, E; Asztalos, S; Biltoft, P

    2007-01-01

    Error rates in a cargo screening system such as the Nuclear Car Wash [1-7] depend on the standard deviation of the background radiation count rate. Because the Nuclear Car Wash is an active interrogation technique, the radiation signal for fissile material must be detected above a background count rate consisting of cosmic, ambient, and neutron-activated radiations. It was suggested previously [1,6] that the Corresponding negative repercussions for the sensitivity of the system were shown. Therefore, to assure the most accurate estimation of the variation, experiments have been performed to quantify components of the actual variance in the background count rate, including variations in generator power, irradiation time, and container contents. The background variance is determined by these experiments to be a factor of 2 smaller than values assumed in previous analyses, resulting in substantially improved projections of system performance for the Nuclear Car Wash

  11. Highly sensitive detection using microring resonator and nanopores

    Science.gov (United States)

    Bougot-Robin, K.; Hoste, J. W.; Le Thomas, N.; Bienstman, P.; Edel, J. B.

    2016-04-01

    One of the most significant challenges facing physical and biological scientists is the accurate detection and identification of single molecules in free-solution environments. The ability to perform such sensitive and selective measurements opens new avenues for a large number of applications in biological, medical and chemical analysis, where small sample volumes and low analyte concentrations are the norm. Access to information at the single or few molecules scale is rendered possible by a fine combination of recent advances in technologies. We propose a novel detection method that combines highly sensitive label-free resonant sensing obtained with high-Q microcavities and position control in nanoscale pores (nanopores). In addition to be label-free and highly sensitive, our technique is immobilization free and does not rely on surface biochemistry to bind probes on a chip. This is a significant advantage, both in term of biology uncertainties and fewer biological preparation steps. Through combination of high-Q photonic structures with translocation through nanopore at the end of a pipette, or through a solid-state membrane, we believe significant advances can be achieved in the field of biosensing. Silicon microrings are highly advantageous in term of sensitivity, multiplexing, and microfabrication and are chosen for this study. In term of nanopores, we both consider nanopore at the end of a nanopipette, with the pore being approach from the pipette with nanoprecise mechanical control. Alternatively, solid state nanopores can be fabricated through a membrane, supporting the ring. Both configuration are discussed in this paper, in term of implementation and sensitivity.

  12. Regulation of early and delayed radiation responses in rat small intestine by capsaicin-sensitive nerves

    International Nuclear Information System (INIS)

    Wang Junru; Zheng Huaien; Kulkarni, Ashwini; Ou Xuemei; Hauer-Jensen, Martin

    2006-01-01

    Purpose: Mast cells protect against the early manifestations of intestinal radiation toxicity, but promote chronic intestinal wall fibrosis. Intestinal sensory nerves are closely associated with mast cells, both anatomically and functionally, and serve an important role in the regulation of mucosal homeostasis. This study examined the effect of sensory nerve ablation on the intestinal radiation response in an established rat model. Methods and Materials: Rats underwent sensory nerve ablation with capsaicin or sham ablation. Two weeks later, a localized segment of ileum was X-irradiated or sham irradiated. Structural, cellular, and molecular changes were examined 2 weeks (early injury) and 26 weeks (chronic injury) after irradiation. The mast cell dependence of the effect of sensory nerve ablation on intestinal radiation injury was assessed using c-kit mutant (Ws/Ws) mast cell-deficient rats. Results: Capsaicin treatment caused a baseline reduction in mucosal mast cell density, crypt cell proliferation, and expression of substance P and calcitonin gene-related peptide, two neuropeptides released by sensory neurons. Sensory nerve ablation strikingly exacerbated early intestinal radiation toxicity (loss of mucosal surface area, inflammation, intestinal wall thickening), but attenuated the development of chronic intestinal radiation fibrosis (collagen I accumulation and transforming growth factor β immunoreactivity). In mast cell-deficient rats, capsaicin treatment exacerbated postradiation epithelial injury (loss of mucosal surface area), but none of the other aspects of radiation injury were affected by capsaicin treatment. Conclusions: Ablation of capsaicin-sensitive enteric neurons exacerbates early intestinal radiation toxicity, but attenuates development of chronic fibroproliferative changes. The effect of capsaicin treatment on the intestinal radiation response is partly mast cell dependent

  13. High contrast computed tomography with synchrotron radiation

    Science.gov (United States)

    Itai, Yuji; Takeda, Tohoru; Akatsuka, Takao; Maeda, Tomokazu; Hyodo, Kazuyuki; Uchida, Akira; Yuasa, Tetsuya; Kazama, Masahiro; Wu, Jin; Ando, Masami

    1995-02-01

    This article describes a new monochromatic x-ray CT system using synchrotron radiation with applications in biomedical diagnosis which is currently under development. The system is designed to provide clear images and to detect contrast materials at low concentration for the quantitative functional evaluation of organs in correspondence with their anatomical structures. In this system, with x-ray energy changing from 30 to 52 keV, images can be obtained to detect various contrast materials (iodine, barium, and gadolinium), and K-edge energy subtraction is applied. Herein, the features of the new system designed to enhance the advantages of SR are reported. With the introduction of a double-crystal monochromator, the high-order x-ray contamination is eliminated. The newly designed CCD detector with a wide dynamic range of 60 000:1 has a spatial resolution of 200 μm. The resulting image quality, which is expected to show improved contrast and spatial resolution, is currently under investigation.

  14. Radiation crosslinking of highly plasticized PVC

    Science.gov (United States)

    Mendizabal, E.; Cruz, L.; Jasso, C. F.; Burillo, G.; Dakin, V. I.

    1996-02-01

    To improve the physical properties of highly plasticized PVC, the polymer was crosslinked by gamma irradiation using a dose rate of 91 kGy/h. The effect of plasticizer type was studied by using three different plasticizers, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB), di(2-ethyl hexyl) phthalate (DOP), and di(2-ethylhexyl terephthalate) (DOTP), and varying irradiation doses. Gel content was determined by soxhlet extraction, tensile measurements were made on a universal testing machine and the mechano-dynamic measurements were made in a dynamic rheometer. It was found that a considerable bonding of plasticizer molecules to macromolelcules takes place along with crosslinking, so that the use of the solvent extraction method for measuring the degree of crosslinking can give erroneous information. Radiation-chemical crosslinking yield ( Gc) and molecular weight of interjunctions chains ( Mc), were calculated for different systems studied. Addition of ethylene glycol dimethacrylate (EGDM) as a crosslinking coagent and dioctyl tin oxide (DOTO) as a stabilizer was also studied. Plasticizers extraction resistance was increased by irradiation treatment.

  15. Radiation crosslinking of highly plasticized PVC

    International Nuclear Information System (INIS)

    Mendizabal, E.; Cruz, L.; Jasso, C.F.; Burillo, G.; Dakin, V.I.

    1996-01-01

    To improve the physical properties of highly plasticized PVC, the polymer was crosslinked by gamma irradiation using a dose rate of 91 kGy/h. The effect of plasticizer type was studied by using three different plasticizers, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB), di(2-ethyl hexyl) phthalate (DOP), and di(2-ethylhexyl terephthalate) (DOTP), and varying irradiation doses. Gel content was determined by soxhlet extraction, tensile measurements were made on a universal testing machine and the mechano-dynamic measurements were made in a dynamic rheometer. It was found that a considerable bonding of plasticizer molecules to macromolecules takes place along with crosslinking, so that the use of the solvent extraction method for measuring the degree of crosslinking can give erroneous information. Radiation-chemical crosslinking yield (G c ) and molecular weight of interjunctions chains (M c ), were calculated for different systems studied. Addition of ethylene glycol dimethyacrylate (EGDM) as a crosslinking coagent and dioctyl tin oxide (DOTO) as a stabilizer was also studied. Plasticizers extraction resistance was increased by irradiation treatment. (author)

  16. NK sensitivity of neuroblastoma cells determined by a highly sensitive coupled luminescent method

    International Nuclear Information System (INIS)

    Ogbomo, Henry; Hahn, Anke; Geiler, Janina; Michaelis, Martin; Doerr, Hans Wilhelm; Cinatl, Jindrich

    2006-01-01

    The measurement of natural killer (NK) cells toxicity against tumor or virus-infected cells especially in cases with small blood samples requires highly sensitive methods. Here, a coupled luminescent method (CLM) based on glyceraldehyde-3-phosphate dehydrogenase release from injured target cells was used to evaluate the cytotoxicity of interleukin-2 activated NK cells against neuroblastoma cell lines. In contrast to most other methods, CLM does not require the pretreatment of target cells with labeling substances which could be toxic or radioactive. The effective killing of tumor cells was achieved by low effector/target ratios ranging from 0.5:1 to 4:1. CLM provides highly sensitive, safe, and fast procedure for measurement of NK cell activity with small blood samples such as those obtained from pediatric patients

  17. Instruction manual for ORNL tandem high abundance sensitivity mass spectrometer

    International Nuclear Information System (INIS)

    Smith, D.H.; McKown, H.S.; Chrisite, W.H.; Walker, R.L.; Carter, J.A.

    1976-06-01

    This manual describes the physical characteristics of the tandem mass spectrometer built by Oak Ridge National Laboratory for the International Atomic Energy Agency. Specific requirements met include ability to run small samples, high abundance sensitivity, good precision and accuracy, and adequate sample throughput. The instrument is capable of running uranium samples as small as 10 -12 g and has an abundance sensitivity in excess of 10 6 . Precision and accuracy are enhanced by a special sweep control circuit. Sample throughput is 6 to 12 samples per day. Operating instructions are also given

  18. A highly sensitive and specific assay for vertebrate collagenase

    International Nuclear Information System (INIS)

    Sodek, J.; Hurum, S.; Feng, J.

    1981-01-01

    A highly sensitive and specific assay for vertebrate collagenase has been developed using a [ 14 C]-labeled collagen substrate and a combination of SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) and fluorography to identify and quantitate the digestion products. The assay was sufficiently sensitive to permit the detection and quantitation of collagenase activity in 0.1 μl of gingival sulcal fluid, and in samples of cell culture medium without prior concentration. The assay has also been used to detect the presence of inhibitors of collagenolytic enzymes in various cell culture fluids. (author)

  19. Effect of free radicals and cultivation media on radiation sensitivities of escherichia coli and related bacteria

    International Nuclear Information System (INIS)

    Ito, Hitoshi

    2000-01-01

    Effects of gamma-irradiation on some strains of Escherichia coli, Salmonella enteritidis and Staphylococcus aureus were investigated in the presence of N 2 , N 2 O and O 2 and with the hydroxyl radical (OH) scavengers glycerol, polyethylene glycerol and formate. Injured cell membrane of bacteria was detected using with MacConkey agar for E. coli and S. enteritidis and 7% NaCl Triptic soy agar for St. aureus instead of Tryptic soy agar for recovery medium. From this study, addition of glycerol significantly reduced the sensitivity in all of strains, and cell membrane was not injured significantly except in radiation sensitive strain E. coli A4-1. When superoxide radicals (O 2 ) were generated during irradiation in the presence of formate, injured cell membrane increased significantly in all of strains. However, molecular oxygen (O 2 ) and OH radicals also had some effects on the damage of cell membrane. These results suggest that most radiation induced cell lethality was responsible to the cooperative effects of intracellular OH radicals and O 2 on DNA with lessor effect of damage on cell membrane by O 2 radicals, O 2 and OH radicals. On the radiation sensitive strain of E. coli, cell lethality occurred significantly by the injury of cell membrane compared with other strains. (author)

  20. Radiation Sensitivity of some Food Borne Bacterial Pathogens in Animal Foods and Minced Meat

    International Nuclear Information System (INIS)

    Mohammed, W.S.; Ali, A.R.; Alexan, A.F.

    2010-01-01

    Bacteriological examination of 100 samples of animal food stuffs (fish meal and bone and meat meal; as models of dry food materials) and 50 samples of minced meat (as a model of moist food materials) revealed the isolation of different bacterial pathogens; Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, Proteus spp., Staph. aureus and Salmonella species, in a decreasing order of occurrence. In the experiment; the dry food stuffs were sterilized in autoclave and the minced meat was sterilized by gamma irradiation at 10 kGy. The efficacy of gamma irradiation against the inoculated bacterial isolates (E coli 0157: H7, Salmonella enteritidis and Staph. aureus) in animal food stuffs and minced meat was investigated. Irradiated samples were stored at room temperature (25 degree C) for 2 weeks. The food borne pathogens used in this study showed a difference in radiation sensitivity. E. coli 0157: H7, Staphylococcus aureus and Salmonella enteritidis were eradicated at 1, 2 and 3 kGy, respectively. Also, inoculated pathogens in minced meat were more sensitive to ionizing radiation than dry animal food stuffs. It could be concluded that low doses of gamma irradiation are effective means of inactivating pathogenic bacteria. This radiation sensitivity is related to the bacterial isolates and the evaluated growth

  1. Mesenchymal stem cells are sensitive to treatment with kinase inhibitors and ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Nicolay, Nils H.; Debus, Juergen; Huber, Peter E. [Heidelberg University Hospital, Department of Radiation Oncology, Heidelberg (Germany); German Cancer Research Center (dkfz), Department of Molecular and Radiation Oncology, Heidelberg (Germany); Sommer, Eva; Lopez Perez, Ramon; Wirkner, Ute [German Cancer Research Center (dkfz), Department of Molecular and Radiation Oncology, Heidelberg (Germany); Bostel, Tilman [Heidelberg University Hospital, Department of Radiation Oncology, Heidelberg (Germany); Ho, Anthony D.; Saffrich, Rainer [Heidelberg University Hospital, Department of Hematology, Oncology and Rheumatology, Heidelberg (Germany); Lahn, Michael [Lilly Research Laboratories, Oncology Early Clinical Investigation, Indianapolis, IN (United States)

    2014-11-15

    Mesenchymal stem cells (MSCs) can regenerate damaged tissues and may therefore be of importance for normal tissue repair after cancer treatment. Small molecule receptor kinase inhibitors (RKIs) have recently been introduced into cancer treatment. However, the influence of these drugs - particularly in combination with radiotherapy - on the survival of MSCs is largely unknown. The sensitivity of human primary MSCs from healthy volunteers and primary human fibroblast cells to small molecule kinase inhibitors of the vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF) and transforming growth factor β (TGFβ) receptors, as well to inhibitors of c-Kit, was examined in combination with ionizing radiation (IR); cell survival and proliferation were assessed. Expression patterns of different kinase receptors and ligands were investigated using gene arrays. MSCs were highly sensitive to the tyrosine kinase inhibitors SU14816 (imatinib) and SU11657 (sunitinib), but showed only moderate sensitivity to the selective TGFβ receptor 1 inhibitor LY2109761. Primary adult human fibroblasts were comparably resistant to all three inhibitors. The addition of IR had an additive or supra-additive effect in the MSCs, but this was not the case for differentiated fibroblasts. Proliferation was markedly reduced in MSCs following kinase inhibition, both with and without IR. Gene expression analysis revealed high levels of the PDGF α and β receptors, and lower levels of the TGFβ receptor 2 and Abl kinase. IR did not alter the expression of kinase receptors or their respective ligands in either MSCs or adult fibroblasts. These data show that MSCs are highly sensitive to RKIs and combination treatments incorporating IR. Expression analyses suggest that high levels of PDGF receptors may contribute to this effect. (orig.) [German] Mesenchymale Stammzellen (MSCs) koennen die Geweberegeneration unterstuetzen und haben daher moeglicherweise eine Rolle bei der Reparatur

  2. Radiation chemistry of high polymers. Final report

    International Nuclear Information System (INIS)

    Dole, M.; Welch, R.A.

    1977-01-01

    Work on calibrating the radiation intensity in our γ-ray source as a function of height and horizontal displacement was completed. For extended chain (high crystallinity) polyethylene (PE) before and after quenching from the melt irradiated at room temperature, the crosslinking yield increased twofold on lowering the crystallinity from 96 to 70%. The G-value for alkyl radical production was about 75% higher in the quenched extended chain sample as compared to the value before quenching. The G (alkyl) values were determined for irradiations at 77K. The rate of decay of the alkyl radicals in PE samples of single crystals having different stem lengths was studied at 80 and 85 0 . It was found that the mole fraction of the slowly decaying free radicals increased with the stem length. Hydrogen gas was found to catalyze both the slow and fast decays. Because hydrogen does not dissolve in the crystalline regions of the PE, the catalytic effect must occur at the amorphous boundary of the crystalline stems. With respect to the kinetics of the allyl radical, either it was found that the data could be explained in terms of two simultaneous but spatially separated second order reactions. As the temperature is raised to 135 0 , the two reactions merge into one. Hydrogen gas has no effect on the decay of the allyl radicals. In the case of the highly crystalline extended chain samples, the allyl decay in some cases follows the simple kinetic equation (1/c) - (1/c 0 ) = k√t, where k is called a time independent diffusion controlled reaction rate constant. The less the crystallinity of the sample the greater the k constant. A preliminary study of isotactic polypropylene (PP) was carried out and a definite hydrogen gas catalysis of the free radical decay in PP was seen. Similarly in crystalline 1-leucine the hydrogen catalytic effect could also be clearly demonstrated

  3. The circadian rhythm for the number and sensitivity of radiation-induced apoptosis in the crypts of mouse small intestine

    International Nuclear Information System (INIS)

    Ijiri, K.; Potten, C.S.

    1990-01-01

    Survival curves were constructed from dose-incidence curves for apoptosis in the crypts of mouse small intestine, using the number of apoptotic cells after high doses (N M ) as maximum cell population size. The mean lethal doses (D 0 ) for the dose range 0-0.5 Gy were calculated for each time of day. A circadian rhythm in both D 0 and N M values was detected, indicating that both the number and sensitivity of radiation-induced apoptosis were changing throughout the day. (author)

  4. High frequency electrical stimulation concurrently induces central sensitization and ipsilateral inhibitory pain modulation.

    Science.gov (United States)

    Vo, L; Drummond, P D

    2013-03-01

    In healthy humans, analgesia to blunt pressure develops in the ipsilateral forehead during various forms of limb pain. The aim of the current study was to determine whether this analgesic response is induced by ultraviolet B radiation (UVB), which evokes signs of peripheral sensitization, or by high-frequency electrical stimulation (HFS), which triggers signs of central sensitization. Before and after HFS and UVB conditioning, sensitivity to heat and to blunt and sharp stimuli was assessed at and adjacent to the treated site in the forearm. In addition, sensitivity to blunt pressure was measured bilaterally in the forehead. The effect of ipsilateral versus contralateral temple cooling on electrically evoked pain in the forearm was then examined, to determine whether HFS or UVB conditioning altered inhibitory pain modulation. UVB conditioning triggered signs of peripheral sensitization, whereas HFS conditioning triggered signs of central sensitization. Importantly, ipsilateral forehead analgesia developed after HFS but not UVB conditioning. In addition, decreases in electrically evoked pain at the HFS-treated site were greater during ipsilateral than contralateral temple cooling, whereas decreases at the UVB-treated site were similar during both procedures. HFS conditioning induced signs of central sensitization in the forearm and analgesia both in the ipsilateral forehead and the HFS-treated site. This ipsilateral analgesia was not due to peripheral sensitization or other non-specific effects, as it failed to develop after UVB conditioning. Thus, the supra-spinal mechanisms that evoke central sensitization might also trigger a hemilateral inhibitory pain modulation process. This inhibitory process could sharpen the boundaries of central sensitization or limit its spread. © 2012 European Federation of International Association for the Study of Pain Chapters.

  5. Are inflationary predictions sensitive to very high energy physics?

    International Nuclear Information System (INIS)

    Burgess, C.P.; Lemieux, F.; Holman, R.; Cline, J.M.

    2003-01-01

    It has been proposed that the successful inflationary description of density perturbations on cosmological scales is sensitive to the details of physics at extremely high (trans-Planckian) energies. We test this proposal by examining how inflationary predictions depend on higher-energy scales within a simple model where the higher-energy physics is well understood. We find the best of all possible worlds: inflationary predictions are robust against the vast majority of high-energy effects, but can be sensitive to some effects in certain circumstances, in a way which does not violate ordinary notions of decoupling. This implies both that the comparison of inflationary predictions with CMB data is meaningful, and that it is also worth searching for small deviations from the standard results in the hopes of learning about very high energies. (author)

  6. Design of highly sensitive multichannel bimetallic photonic crystal fiber biosensor

    Science.gov (United States)

    Hameed, Mohamed Farhat O.; Alrayk, Yassmin K. A.; Shaalan, Abdelhamid A.; El Deeb, Walid S.; Obayya, Salah S. A.

    2016-10-01

    A design of a highly sensitive multichannel biosensor based on photonic crystal fiber is proposed and analyzed. The suggested design has a silver layer as a plasmonic material coated by a gold layer to protect silver oxidation. The reported sensor is based on detection using the quasi transverse electric (TE) and quasi transverse magnetic (TM) modes, which offers the possibility of multichannel/multianalyte sensing. The numerical results are obtained using a finite element method with perfect matched layer boundary conditions. The sensor geometrical parameters are optimized to achieve high sensitivity for the two polarized modes. High-refractive index sensitivity of about 4750 nm/RIU (refractive index unit) and 4300 nm/RIU with corresponding resolutions of 2.1×10-5 RIU, and 2.33×10-5 RIU can be obtained according to the quasi TM and quasi TE modes of the proposed sensor, respectively. Further, the reported design can be used as a self-calibration biosensor within an unknown analyte refractive index ranging from 1.33 to 1.35 with high linearity and high accuracy. Moreover, the suggested biosensor has advantages in terms of compactness and better integration of microfluidics setup, waveguide, and metallic layers into a single structure.

  7. Biological effects of high LET radiations

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Masami [Nagasaki Univ. (Japan). Faculty of Pharmaceutical Sciences

    1997-03-01

    Biological effect of radiation is different by a kind of it greatly. Heavy ions were generally more effective in cell inactivation, chromosome aberration induction, mutation induction and neoplastic cell transformation induction than {gamma}-rays in SHE cells. (author)

  8. Radiation Safety Issues in High Altitude Commercial Aircraft

    Science.gov (United States)

    Wilson, John W.; Cucinotta, Francis A.; Shinn, Judy L.

    1995-01-01

    The development of a global economy makes the outlook for high speed commercial intercontinental flight feasible, and the development of various configurations operating from 20 to 30 km have been proposed. In addition to the still unresolved issues relating to current commercial operations (12-16 km), the higher dose rates associated with the higher operating altitudes makes il imperative that the uncertainties in the atmospheric radiation environment and the associated health risks be re-examined. Atmospheric radiation associated with the galactic cosmic rays forms a background level which may, under some circumstances, exceed newly recommended allowable exposure limits proposed on the basis of recent evaluations of the A -bomb survivor data (due to increased risk coefficients). These larger risk coefficients, within the context of the methodology for estimating exposure limits, are resulting in exceedingly low estimated allowable exposure limits which may impact even present day flight operations and was the reason for the CEC workshop in Luxembourg (1990). At higher operating altitudes, solar particles events can produce exposures many orders of magnitude above background levels and pose significant health risks to the most sensitive individuals (such as during pregnancy). In this case the appropriate quality factors are undefined, and some evidence exists which indicates that the quality factor for stochastic effects is a substantial underestimate.

  9. Effects of radio sensitizers in the vulcanization of natural rubber latex induced by gamma radiation

    International Nuclear Information System (INIS)

    Souza, A. de; Canavel, V.; Araujo, S.C. de; Guedes, S.M.L.

    1992-01-01

    The effect of C Cl 4 and n-butyl acrylate as a sensitizer for radiation vulcanization of 60% DRC natural rubber latex with gamma rays, was studied relating tensile strength of vulcanized latex. The vulcanization dose is 200 kGy for natural rubber latex and it decreases to 40 kGy and to 9 kGy in the presence of C Cl 4 / potassium laureate and n-butyl acrylate / t-butyl hydroperoxide, respectively. The H 2 O 2 as a co-sensitizer does not change the efficiency of the combination of these sensitizers. The IV spectra show the formation of C=O after the irradiation as consequence of oxidation reactions. (author)

  10. Radiogenic male breast cancer with in vitro sensitivity to ionizing radiation and bleomycin

    International Nuclear Information System (INIS)

    Greene, M.H.; Goedert, J.J.; Bech-Hansen, N.T.; McGuire, D.; Paterson, M.C.; Fraumeni, J.F. Jr.

    1983-01-01

    A cytogenetically normal man with gynecomastia and a family history of diverse cancers developed adenocarcinoma of the breast 30 years following thymic irradiation. In vitro experiments measuring colony-forming ability of cultured skin fibroblasts from family members implied that the patient had a small but significant increase in sensitivity to ionizing radiation, and a moderate increase in sensitivity to bleomycin, a radiomimetic drug. Enhanced radiosensitivity of fibroblasts from the patient's mother, and bleomycin sensitivity of fibroblasts from the sister suggested, but did not prove, that genetic susceptibility affected the risk of radiogenic cancer in this individual. In vitro studies of cancer-prone kindreds are a useful research strategy in delineating mechanisms of carcinogenesis

  11. Inhibition of phosphatidylinositol-3-kinase causes increased sensitivity to radiation through a PKB-dependent mechanism

    International Nuclear Information System (INIS)

    Gottschalk, Alexander R.; Doan, Albert; Nakamura, Jean L.; Stokoe, David; Haas-Kogan, Daphne A.

    2005-01-01

    Purpose: To identify whether inhibition of phosphatidylinositol-3-kinase (PI3K) causes increased radiosensitivity through inhibition of protein kinase B (PKB), implicating PKB as an important therapeutic target in prostate cancer. Methods and Materials: The prostate cancer cell line LNCaP was treated with the PI3K inhibitor LY294002, radiation, and combinations of the two therapies. Apoptosis and survival were measured by cell cycle analysis, Western blot analysis for cleaved poly (ADP-ribose) polymerase, and clonogenic survival. To test the hypothesis that inhibition of PKB is responsible for LY294002-induced radiosensitivity, LNCaP cells expressing a constitutively active form of PKB were used. Results: The combination of PI3K inhibition and radiation caused an increase in apoptosis and a decrease in clonogenic survival when compared to either modality alone. The expression of constitutively activated PKB blocked apoptosis induced by combination of PI3K inhibition and radiation and prevented radiosensitization by LY294002. Conclusion: These data indicate that PI3K inhibition increases sensitivity of prostate cancer cell lines to ionizing radiation through inactivation of PKB. Therefore, PTEN mutations, which lead to PKB activation, may play an important role in the resistance of prostate cancer to radiation therapy. Targeted therapy against PKB could be beneficial in the management of prostate cancer patients

  12. Sensitivity of the green algae Chlamydomonas reinhardtii to gamma radiation: Photosynthetic performance and ROS formation

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Tânia, E-mail: tania.gomes@niva.no [Norwegian Institute for Water Research (NIVA), Section of Ecotoxicology and Risk Assessment, Gaustadalléen 21, N-0349, Oslo (Norway); Centre for Environmental Radioactivity, Norwegian University of Life Sciences (NMBU), Post Box 5003, N-1432 Ås (Norway); Xie, Li [Norwegian Institute for Water Research (NIVA), Section of Ecotoxicology and Risk Assessment, Gaustadalléen 21, N-0349, Oslo (Norway); Centre for Environmental Radioactivity, Norwegian University of Life Sciences (NMBU), Post Box 5003, N-1432 Ås (Norway); Brede, Dag; Lind, Ole-Christian [Centre for Environmental Radioactivity, Norwegian University of Life Sciences (NMBU), Post Box 5003, N-1432 Ås (Norway); Department for Environmental Sciences, Faculty of Environmental Science & Technology, Norwegian University of Life Sciences (NMBU), Post Box 5003, N-1432, Ås (Norway); Solhaug, Knut Asbjørn [Centre for Environmental Radioactivity, Norwegian University of Life Sciences (NMBU), Post Box 5003, N-1432 Ås (Norway); Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences (NMBU), Postbox 5003, N-1432, Ås (Norway); Salbu, Brit [Centre for Environmental Radioactivity, Norwegian University of Life Sciences (NMBU), Post Box 5003, N-1432 Ås (Norway); Department for Environmental Sciences, Faculty of Environmental Science & Technology, Norwegian University of Life Sciences (NMBU), Post Box 5003, N-1432, Ås (Norway); and others

    2017-02-15

    Highlights: • Chlorophyll fluorescence parameters affected at higher dose rates. • Changes in PSII associated with electron transport and energy dissipation pathways. • Dose-dependent ROS production in algae exposed to gamma radiation. • Decrease in photosynthetic efficiency connected to ROS formation. - Abstract: The aquatic environment is continuously exposed to ionizing radiation from both natural and anthropogenic sources, making the characterization of ecological and health risks associated with radiation of large importance. Microalgae represent the main source of biomass production in the aquatic ecosystem, thus becoming a highly relevant biological model to assess the impacts of gamma radiation. However, little information is available on the effects of gamma radiation on microalgal species, making environmental radioprotection of this group of species challenging. In this context, the present study aimed to improve the understanding of the effects and toxic mechanisms of gamma radiation in the unicellular green algae Chlamydomonas reinhardtii focusing on the activity of the photosynthetic apparatus and ROS formation. Algal cells were exposed to gamma radiation (0.49–1677 mGy/h) for 6 h and chlorophyll fluorescence parameters obtained by PAM fluorometry, while two fluorescent probes carboxy-H{sub 2}DFFDA and DHR 123 were used for the quantification of ROS. The alterations seen in functional parameters of C. reinhardtii PSII after 6 h of exposure to gamma radiation showed modifications of PSII energy transfer associated with electron transport and energy dissipation pathways, especially at the higher dose rates used. Results also showed that gamma radiation induced ROS in a dose-dependent manner under both light and dark conditions. The observed decrease in photosynthetic efficiency seems to be connected to the formation of ROS and can potentially lead to oxidative stress and cellular damage in chloroplasts. To our knowledge, this is the first

  13. Sensitivity of the green algae Chlamydomonas reinhardtii to gamma radiation: Photosynthetic performance and ROS formation

    International Nuclear Information System (INIS)

    Gomes, Tânia; Xie, Li; Brede, Dag; Lind, Ole-Christian; Solhaug, Knut Asbjørn; Salbu, Brit

    2017-01-01

    Highlights: • Chlorophyll fluorescence parameters affected at higher dose rates. • Changes in PSII associated with electron transport and energy dissipation pathways. • Dose-dependent ROS production in algae exposed to gamma radiation. • Decrease in photosynthetic efficiency connected to ROS formation. - Abstract: The aquatic environment is continuously exposed to ionizing radiation from both natural and anthropogenic sources, making the characterization of ecological and health risks associated with radiation of large importance. Microalgae represent the main source of biomass production in the aquatic ecosystem, thus becoming a highly relevant biological model to assess the impacts of gamma radiation. However, little information is available on the effects of gamma radiation on microalgal species, making environmental radioprotection of this group of species challenging. In this context, the present study aimed to improve the understanding of the effects and toxic mechanisms of gamma radiation in the unicellular green algae Chlamydomonas reinhardtii focusing on the activity of the photosynthetic apparatus and ROS formation. Algal cells were exposed to gamma radiation (0.49–1677 mGy/h) for 6 h and chlorophyll fluorescence parameters obtained by PAM fluorometry, while two fluorescent probes carboxy-H 2 DFFDA and DHR 123 were used for the quantification of ROS. The alterations seen in functional parameters of C. reinhardtii PSII after 6 h of exposure to gamma radiation showed modifications of PSII energy transfer associated with electron transport and energy dissipation pathways, especially at the higher dose rates used. Results also showed that gamma radiation induced ROS in a dose-dependent manner under both light and dark conditions. The observed decrease in photosynthetic efficiency seems to be connected to the formation of ROS and can potentially lead to oxidative stress and cellular damage in chloroplasts. To our knowledge, this is the first report

  14. Hawking radiation of a high-dimensional rotating black hole

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Ren; Zhang, Lichun; Li, Huaifan; Wu, Yueqin [Shanxi Datong University, Institute of Theoretical Physics, Department of Physics, Datong (China)

    2010-01-15

    We extend the classical Damour-Ruffini method and discuss Hawking radiation spectrum of high-dimensional rotating black hole using Tortoise coordinate transformation defined by taking the reaction of the radiation to the spacetime into consideration. Under the condition that the energy and angular momentum are conservative, taking self-gravitation action into account, we derive Hawking radiation spectrums which satisfy unitary principle in quantum mechanics. It is shown that the process that the black hole radiates particles with energy {omega} is a continuous tunneling process. We provide a theoretical basis for further studying the physical mechanism of black-hole radiation. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-03-18

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

  16. Transcription and activity of antioxidant proteins after ionization irradiation of radiation-resistant and radiation-sensitive mice

    International Nuclear Information System (INIS)

    Hardmeier, R.

    1998-03-01

    The involvernent of antioxidant proteins catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH px), and thioredoxin (TRX) in radiobiological processes has been described at the enzyme activity level. We were interested in examining the transcription of these proteins in a mammalian system following ionizing irradiation. In order to answer the question whether radiation effects in sensitive mice (Balb/c) (RS) showed differences at the transcriptional level from radiation effects in resistant mice (C3H) (RR). We exposed the whole body of these strains to X/rays doses of 2, 4, and 6 Gy and sacrificed the animals 5, 15, and 30 minutes after irradiation. The mRNA was isolated from liver and hybrized with probes for antioxidant enzymes and thioredoxin, β-actin was used as a housekeeping gene control. Antioxidant enzyme activities were determined by standard assays. Parameters for aromatic hydroxylation (o-Tyr) and lipid peroxidation (MDA) were determined by HPLC methods. Antioxidant transcription was unchanged in contrast to antioxidant activities. SOD and CAT activities were elevated within 15 minutes in RR animals but not in RS at all radiation doses. Glutathione peroxidase activity was not different between RR and RS mice, and was only moderately elevated after irradiation. No significant differences were found between RR and RS animals at the oxidation level, although a radiation dose-dependent increase of oxidation products was detected in both groups. Quantification of thioredoxin mRNA revealed that RR mice transcribed this protein at a significantly higher level at an earlier time point (5 minutes) than did RS mice. This delay may well be responsible for the radioresistance although no quantitative differences were found. As unchanged transcription of antioxidant enzymes could not have been responsible for the increased antioxidant enzyme activities, preformed antioxidant enzymes may have been released by irradiation. This would be in agreement

  17. Combined radiation-protective and radiation-sensitizing agents. IV. Measurement of intracellular protector concentrations

    International Nuclear Information System (INIS)

    Koch, C.J.; Stobbe, C.C.; Hettiaratchi, P.

    1989-01-01

    Radiosensitization of hypoxic V79 Chinese hamster cells by 0.5 mM misonidazole at approximately 0-4 degrees C is substantially enhanced by pretreating the cells overnight with 0.1 mM buthionine sulfoximine, which lowers the cellular glutathione content to 5% of control values (from 4 mM to approximately 0.2 mM). The enhanced sensitization is reversed by concentrations of exogenous cysteine that are much lower (0.02 mM) than the original glutathione content. Reduced Co-enzyme A affords reversal of the enhancing effect at concentrations of about 1 mM. Sodium ascorbate gives no protection at all even at concentrations of 2 mM. The intracellular concentration of the reducing agents was measured using a spin-through oil technique. There was no diffusion of Co-A (MW greater than 750) or ascorbate (excluded by charge) into the cells. In contrast, cysteine was rapidly concentrated by factors of 4-10, even at the low temperatures used. Extracellular ascorbate's inability to radioprotect argues against electron transfer across the cell membrane as a mechanism for radioprotection. This mechanism could have explained the ability of exogenous thiols to radioprotect in former studies using glutathione, and in the present studies using Co-A. The potential of cysteine to be concentrated by cells poses a problem in the interpretation of exogenous protection by non-diffusing thiols, since trace contamination by cysteine could lead to the actual protection observed. Cysteine could also be formed by exchange reactions of exogenous thiols with the disulfide of cysteine, present in all media formulations

  18. The theoretical basis and clinical methodology for stereotactic interstitial brain tumor irradiation using iododeoxyuridine as a radiation sensitizer and samarium-145 as a brachytherapy source

    International Nuclear Information System (INIS)

    Goodman, J.H.; Gahbauer, R.A.; Kanellitsas, C.; Clendenon, N.R.; Laster, B.H.; Fairchild, R.G.

    1989-01-01

    High grade astrocytomas have proven resistant to all conventional therapy. A technique to produce radiation enhancement during interstitial brain tumor irradiation by using a radiation sensitizer (IdUrd) and by stimulation of Auger electron cascades through absorption of low energy photons in iodine (Photon activation) is described. Clinical studies using IdUrd, 192 Ir as a brachytherapy source, and external radiation have produced promising results. Substituting samarium-145 for 192 Ir in this protocol is expected to produce enhanced results. 15 refs

  19. Folic acid deficiency increases chromosomal instability, chromosome 21 aneuploidy and sensitivity to radiation-induced micronuclei

    International Nuclear Information System (INIS)

    Beetstra, Sasja; Thomas, Philip; Salisbury, Carolyn; Turner, Julie; Fenech, Michael

    2005-01-01

    Folic acid deficiency can lead to uracil incorporation into DNA, hypomethylation of DNA, inefficient DNA repair and increase chromosome malsegregation and breakage. Because ionising radiation increases demand for efficient DNA repair and also causes chromosome breaks we hypothesised that folic acid deficiency may increase sensitivity to radiation-induced chromosome breakage. We tested this hypothesis by using the cytokinesis-block micronucleus assay in 10 day WIL2-NS cell cultures at four different folic acid concentrations (0.2, 2, 20, and 200 nM) that span the 'normal' physiological range in humans. The study showed a significant dose-dependent increase in frequency of binucleated cells with micronuclei and/or nucleoplasmic bridges with decreasing folic acid concentration (P < 0.0001, P = 0.028, respectively). These biomarkers of chromosomal instability were also increased in cells irradiated (1.5 Gy γ-rays) on day 9 relative to un-irradiated controls (P < 0.05). Folic acid deficiency and γ-irradiation were shown to have a significant interactive effect on frequency of cells containing micronuclei (two-way ANOVA, interaction P 0.0039) such that the frequency of radiation-induced micronucleated cells (i.e. after subtracting base-line frequency of un-irradiated controls) increased with decreasing folic acid concentration (P-trend < 0.0001). Aneuploidy of chromosome 21, apoptosis and necrosis were increased by folic acid deficiency but not by ionising radiation. The results of this study show that folate status has an important impact on chromosomal stability and is an important modifying factor of cellular sensitivity to radiation-induced genome damage

  20. Butyrate down regulates BCL-XL and sensitizes human fibroblasts to radiation and chemotherapy induced apoptosis

    International Nuclear Information System (INIS)

    Chung, Diana H.; Ljungman, Mats; Zhang Fenfen; Chen Feng; McLaughlin, William P.

    1997-01-01

    Purpose/Objective: Butyrate is a short chain fatty acid that has been implicated in the induction of cell cycle arrest, cell differentiation and apoptosis. The purpose of this study was to determine if butyrate treatment sensitizes cells to radiation or chemotherapy induced apoptosis. Materials and Methods: Normal neonatal human diploid fibroblasts were used throughout this study. Apoptosis was scored and quantified using three different methods. First, cell morphology using propidium iodide and fluorescence microscopy was used to qualitatively determine apoptosis and to quantify the percentage of cells undergoing apoptosis. Second, apoptosis induced DNA degradation was scored by quantifying the amount of cells appearing in a sub-G1 peak using fixed and PI-stained cells and flow cytometry. Third, apoptosis-induced DNA degradation was examined by using an assay involving direct lysis of cells in the wells of agarose gels followed by conventional gel electrophoresis. Western blotting was used to quantify the cellular levels of the apoptosis regulators, Bcl-2, Bcl-XL and Bax. Results: Human diploid fibroblasts, which were resistant to radiation induced apoptosis, were found to undergo massive apoptosis when radiation was combined with butyrate treatment. Sensitization was obtained when butyrate was added before or after radiation although the combination of both pre and post-treatment was the most effective. Butyrate was also found to enhance UV light and cisplatin-induced apoptosis. These findings correlated with a reduction of the apoptosis antagonist Bcl-XL. Bcl-XL levels significantly dropped in a time and dose dependent manner. In addition, butyrate effectively blocked UV-induced accumulation of p53. Conclusion: Our results suggest that butyrate may be an attractive agent to use in combination with radiation or chemotherapy to lower the apoptotic threshold of tumor cells, regardless of the p53 status of the tumor cells

  1. Sensitivity and Acclimation of Three Canopy-Forming Seaweeds to UVB Radiation and Warming

    KAUST Repository

    Xiao, Xi; de Bettignies, Thibaut; Olsen, Ylva S.; Agusti, Susana; Duarte, Carlos M.; Wernberg, Thomas

    2015-01-01

    Canopy-forming seaweeds, as primary producers and foundation species, provide key ecological services. Their responses to multiple stressors associated with climate change could therefore have important knock-on effects on the functioning of coastal ecosystems. We examined interactive effects of UVB radiation and warming on juveniles of three habitat-forming subtidal seaweeds from Western Australia–Ecklonia radiata, Scytothalia dorycarpa and Sargassum sp. Fronds were incubated for 14 days at 16–30°C with or without UVB radiation and growth, health status, photosynthetic performance, and light absorbance measured. Furthermore, we used empirical models from the metabolic theory of ecology to evaluate the sensitivity of these important seaweeds to ocean warming. Results indicated that responses to UVB and warming were species specific, with Sargassum showing highest tolerance to a broad range of temperatures. Scytothalia was most sensitive to elevated temperature based on the reduced maximum quantum yields of PSII; however, Ecklonia was most sensitive, according to the comparison of activation energy calculated from Arrhenius’ model. UVB radiation caused reduction in the growth, physiological responses and thallus health in all three species. Our findings indicate that Scytothalia was capable of acclimating in response to UVB and increasing its light absorption efficiency in the UV bands, probably by up-regulating synthesis of photoprotective compounds. The other two species did not acclimate over the two weeks of exposure to UVB. Overall, UVB and warming would severely inhibit the growth and photosynthesis of these canopy-forming seaweeds and decrease their coverage. Differences in the sensitivity and acclimation of major seaweed species to temperature and UVB may alter the balance between species in future seaweed communities under climate change.

  2. Sensitivity and Acclimation of Three Canopy-Forming Seaweeds to UVB Radiation and Warming

    KAUST Repository

    Xiao, Xi

    2015-12-02

    Canopy-forming seaweeds, as primary producers and foundation species, provide key ecological services. Their responses to multiple stressors associated with climate change could therefore have important knock-on effects on the functioning of coastal ecosystems. We examined interactive effects of UVB radiation and warming on juveniles of three habitat-forming subtidal seaweeds from Western Australia–Ecklonia radiata, Scytothalia dorycarpa and Sargassum sp. Fronds were incubated for 14 days at 16–30°C with or without UVB radiation and growth, health status, photosynthetic performance, and light absorbance measured. Furthermore, we used empirical models from the metabolic theory of ecology to evaluate the sensitivity of these important seaweeds to ocean warming. Results indicated that responses to UVB and warming were species specific, with Sargassum showing highest tolerance to a broad range of temperatures. Scytothalia was most sensitive to elevated temperature based on the reduced maximum quantum yields of PSII; however, Ecklonia was most sensitive, according to the comparison of activation energy calculated from Arrhenius’ model. UVB radiation caused reduction in the growth, physiological responses and thallus health in all three species. Our findings indicate that Scytothalia was capable of acclimating in response to UVB and increasing its light absorption efficiency in the UV bands, probably by up-regulating synthesis of photoprotective compounds. The other two species did not acclimate over the two weeks of exposure to UVB. Overall, UVB and warming would severely inhibit the growth and photosynthesis of these canopy-forming seaweeds and decrease their coverage. Differences in the sensitivity and acclimation of major seaweed species to temperature and UVB may alter the balance between species in future seaweed communities under climate change.

  3. Development of High Sensitivity Nuclear Emulsion and Fine Grained Emulsion

    Science.gov (United States)

    Kawahara, H.; Asada, T.; Naka, T.; Naganawa, N.; Kuwabara, K.; Nakamura, M.

    2014-08-01

    Nuclear emulsion is a particle detector having high spacial resolution and angular resolution. It became useful for large statistics experiment thanks to the development of automatic scanning system. In 2010, a facility for emulsion production was introduced and R&D of nuclear emulsion began at Nagoya university. In this paper, we present results of development of the high sensitivity emulsion and fine grained emulsion for dark matter search experiment. Improvement of sensitivity is achieved by raising density of silver halide crystals and doping well-adjusted amount of chemicals. Production of fine grained emulsion was difficult because of unexpected crystal condensation. By mixing polyvinyl alcohol (PVA) to gelatin as a binder, we succeeded in making a stable fine grained emulsion.

  4. Development of High Sensitivity Nuclear Emulsion and Fine Grained Emulsion

    International Nuclear Information System (INIS)

    Kawahara, H.; Asada, T.; Naka, T.; Naganawa, N.; Kuwabara, K.; Nakamura, M.

    2014-01-01

    Nuclear emulsion is a particle detector having high spacial resolution and angular resolution. It became useful for large statistics experiment thanks to the development of automatic scanning system. In 2010, a facility for emulsion production was introduced and R and D of nuclear emulsion began at Nagoya university. In this paper, we present results of development of the high sensitivity emulsion and fine grained emulsion for dark matter search experiment. Improvement of sensitivity is achieved by raising density of silver halide crystals and doping well-adjusted amount of chemicals. Production of fine grained emulsion was difficult because of unexpected crystal condensation. By mixing polyvinyl alcohol (PVA) to gelatin as a binder, we succeeded in making a stable fine grained emulsion

  5. Radiation damage in molybdenum and tungsten in high neutron fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Veljkovic, S; Milasin, N [Institute of Nuclear Sciences Boris Kidric, Department of Reactor Materials, Vinca, Beograd (Serbia and Montenegro)

    1964-04-15

    The effects of radiation on molybdenum and tungsten in high neutron fluxes are presented. The changes induced, particularly defects with a high migration activation energy, are analyzed. The correlation of these changes with the basic concepts of radiation damage in solids is considered. An attempt is made to relate the defects studied with the changes in macroscopic properties (author)

  6. Radiation damage in molybdenum and tungsten in high neutron fluxes

    International Nuclear Information System (INIS)

    Veljkovic, S.; Milasin, N.

    1964-01-01

    The effects of radiation on molybdenum and tungsten in high neutron fluxes are presented. The changes induced, particularly defects with a high migration activation energy, are analyzed. The correlation of these changes with the basic concepts of radiation damage in solids is considered. An attempt is made to relate the defects studied with the changes in macroscopic properties (author)

  7. Online high sensitivity measurement system for transuranic aerosols

    International Nuclear Information System (INIS)

    Kordas, J.F.; Phelps, P.L.

    1976-01-01

    A measurement system for transuranic aerosols has been designed that will be able to withstand the corrosive nature of stack effluents and yet have extremely high sensitivity. It will be capable of measuring 1 maximum permissible concentration (MPC) of plutonium or americium in 30 minutes with a fractional standard deviation of less than 0.33. Background resulting from 218 Po is eliminated by alpha energy discrimination and a decay scheme analysis. A microprocessor controls all data acquisition, data reduction, and instrument calibration

  8. Recent trends in high spin sensitivity magnetic resonance

    Science.gov (United States)

    Blank, Aharon; Twig, Ygal; Ishay, Yakir

    2017-07-01

    new ideas, show how these limiting factors can be mitigated to significantly improve the sensitivity of induction detection. Finally, we outline some directions for the possible applications of high-sensitivity induction detection in the field of electron spin resonance.

  9. Population sensitivities of animals to chronic ionizing radiation-model predictions from mice to elephant.

    Science.gov (United States)

    Sazykina, Tatiana G

    2018-02-01

    Model predictions of population response to chronic ionizing radiation (endpoint 'morbidity') were made for 11 species of warm-blooded animals, differing in body mass and lifespan - from mice to elephant. Predictions were made also for 3 bird species (duck, pigeon, and house sparrow). Calculations were based on analytical solutions of the mathematical model, simulating a population response to low-LET ionizing radiation in an ecosystem with a limiting resource (Sazykina, Kryshev, 2016). Model parameters for different species were taken from biological and radioecological databases; allometric relationships were employed for estimating some parameter values. As a threshold of decreased health status in exposed populations ('health threshold'), a 10% reduction in self-repairing capacity of organisms was suggested, associated with a decline in ability to sustain environmental stresses. Results of the modeling demonstrate a general increase of population vulnerability to ionizing radiation in animal species of larger size and longevity. Populations of small widespread species (mice, house sparrow; body mass 20-50 g), which are characterized by intensive metabolism and short lifespan, have calculated 'health thresholds' at dose rates about 6.5-7.5 mGy day -1 . Widespread animals with body mass 200-500 g (rat, common pigeon) - demonstrate 'health threshold' values at 4-5 mGy day -1 . For populations of animals with body mass 2-5 kg (rabbit, fox, raccoon), the indicators of 10% health decrease are in the range 2-3.4 mGy day -1 . For animals with body mass 40-100 kg (wolf, sheep, wild boar), thresholds are within 0.5-0.8 mGy day -1 ; for herbivorous animals with body mass 200-300 kg (deer, horse) - 0.5-0.6 mGy day -1 . The lowest health threshold was estimated for elephant (body mass around 5000 kg) - 0.1 mGy day -1 . According to the model results, the differences in population sensitivities of warm-blooded animal species to ionizing radiation are generally

  10. Studies on the Mechanism of Radiation Resistance in Micrococcus Radiodurans and its Sensitization

    Energy Technology Data Exchange (ETDEWEB)

    Kitayama, S.; Matsuyama, A. [Radiobiology Laboratory, Institute of Physical and Chemical Research, Wako-shi, Saitama-ken (Japan)

    1978-06-15

    Efficient and accurate repair of radiation-induced lesions in M. radiodurans was investigated as to the cause of its extreme radioresistance. The cells were made permeable to deoxyribonucleoside triphosphate by treatment with non-ionic detergent, Triton X-100. After irradiation with 2 krad gamma rays more than 80% of the single-strand scissions were rejoined in the permeable cells within 10 min at 37 Degree-Sign C. This fast repair process requires the presence of deoxyribonucleoside triphosphates and NAD. However, rejoining of DNA strand scission was incomplete after prolonged incubation in the permeable cells. This suggests that alternate repair reaction(s) is necessary for complete recovery. The other type of radiation lesion was found by postirradiation incubation at non-permissive temperature, which markedly sensitizes this bacterium to radiation. Postincubation at this temperature also sensitizes the cells to chemicals that damage DNA. The extreme radioresistance of this bacterium was also lost by mutation and an isolated radiosensitive mutant showed almost the same radiosensitivity as E. coli K12 or B/r. These results are discussed in connection with the extreme radioresistance of M. radiodurans. (author)

  11. Studies on the mechanism of radiation resistance in Micrococcus radiodurans and its sensitization

    International Nuclear Information System (INIS)

    Kitayama, S.; Matsuyama, A.

    1978-01-01

    Efficient and accurate repair of radiation-induced lesions in M. radiodurans was investigated as to the cause of its extreme radioresistance. The cells were made permeable to deoxyribonucleoside triphosphate by treatment with non-ionic detergent, Triton X-100. After irradiation with 2 krad gamma rays more than 80% of the single-strand scissions were rejoined in the permeable cells within 10 min at 37 0 C. This fast repair process requires the presence of deoxyribonucleoside triphosphates and NAD. However, rejoining of DNA strand scission was incomplete after prolonged incubation in the permeable cells. This suggests that alternate repair reaction(s) is necessary for complete recovery. The other type of radiation lesion was found by post-irradiation incubation at non-permissive temperature, which markedly sensitizes this bacterium to radiation. Postincubation at this temperature also sensitizes the cells to chemicals that damage DNA. The extreme radioresistance of this bacterium was also lost by mutation and an isolated radiosensitive mutant showed almost the same radiosensitivity as E. coli K12 or B/r. These results are discussed in connection with the extreme radioresistance of M. radiodurans. (author)

  12. Modification of the cellular heat sensitivity of cucumber by growth under supplemental ultraviolet-B radiation

    International Nuclear Information System (INIS)

    Caldwell, C.R.

    1994-01-01

    The effect of ultraviolet B (UV-B) radiation on the thermal sensitivity of cucumber (Cucumis sativus L.) was studied using UV-B-sensitive cv Poinsett 76 and UV-B-resistant cv Ashley grown under control and elevated (300 mW m -2 ) UV-B radiation levels. Using both cotyledon and leaf discs, the ability of the tissue to reduce triphenyl tetrazolium chloride (TTC) was determined after treatment at 50 degrees C for various times. Semilogarithmic plots of TTC reduction as a function of time at 50 degrees were curvilinear. They were monophasic for the control cucumber and biphasic for cucumber grown in the presence of elevated UV-B. Treatment of cucumber plants at 37 degrees C for 24 h or of tissue discs at acute UV-B levels for 1 h further modified their response to elevated temperature. These results suggest that growth of cucumber under enhanced UV-B radiation levels increased its ability to withstand elevated temperatures. 19 refs., 2 figs., 2 tabs

  13. [Fitness of workers with particular sensitivity to non-ionizing radiation].

    Science.gov (United States)

    Moccaldi, R; Grandi, C

    2011-01-01

    Chapter IV and V of Title VIII of D.Lgs 81/2008, implementing the Directives 2004/40/EC respectively (protection of workers exposed to electromagnetic fields) and 2006/25/EC (protection of workers exposed to artificial optical radiation), make frequent reference to the workers as "at particular risk" namely those workers who, by their biological or pathological characteristics, lifestyles, multiple exposure to other risk factors, may be more susceptible to the effects of electromagnetic fields or optical radiation. The identification of workers with particular sensitivity is essential for health surveillance, in particular regarding the determination of fitness. The operational guidance on Title VIII of D.Lgs 81/2008 drafted by the Italian Technical Coordination for Safety in the workplace of Regions and Autonomous Provinces (Document No. 1-2009), in collaboration with ISPESL and ISS, includes a preliminary identification of the categories of workers considered most susceptible to the risk from exposure to electromagnetic fields and optical radiation. On the basis of this information the authors identified more focused and structured classes of workers to be considered as "particularly sensitive to risk", it is not only related to a specific wavelength, but based on a comprehensive risk assessment in individual exposure situation, with regard to the exposure levels, any multiple exposures, the possibility of adequate personal protection.

  14. High-sensitivity bend angle measurements using optical fiber gratings.

    Science.gov (United States)

    Rauf, Abdul; Zhao, Jianlin; Jiang, Biqiang

    2013-07-20

    We present a high-sensitivity and more flexible bend measurement method, which is based on the coupling of core mode to the cladding modes at the bending region in concatenation with optical fiber grating serving as band reflector. The characteristics of a bend sensing arm composed of bending region and optical fiber grating is examined for different configurations including single fiber Bragg grating (FBG), chirped FBG (CFBG), and double FBGs. The bend loss curves for coated, stripped, and etched sections of fiber in the bending region with FBG, CFBG, and double FBG are obtained experimentally. The effect of separation between bending region and optical fiber grating on loss is measured. The loss responses for single FBG and CFBG configurations are compared to discover the effectiveness for practical applications. It is demonstrated that the sensitivity of the double FBG scheme is twice that of the single FBG and CFBG configurations, and hence acts as sensitivity multiplier. The bend loss response for different fiber diameters obtained through etching in 40% hydrofluoric acid, is measured in double FBG scheme that resulted in a significant increase in the sensitivity, and reduction of dead-zone.

  15. Sensitivity of the green algae Chlamydomonas reinhardtii to gamma radiation: Photosynthetic performance and ROS formation.

    Science.gov (United States)

    Gomes, Tânia; Xie, Li; Brede, Dag; Lind, Ole-Christian; Solhaug, Knut Asbjørn; Salbu, Brit; Tollefsen, Knut Erik

    2017-02-01

    The aquatic environment is continuously exposed to ionizing radiation from both natural and anthropogenic sources, making the characterization of ecological and health risks associated with radiation of large importance. Microalgae represent the main source of biomass production in the aquatic ecosystem, thus becoming a highly relevant biological model to assess the impacts of gamma radiation. However, little information is available on the effects of gamma radiation on microalgal species, making environmental radioprotection of this group of species challenging. In this context, the present study aimed to improve the understanding of the effects and toxic mechanisms of gamma radiation in the unicellular green algae Chlamydomonas reinhardtii focusing on the activity of the photosynthetic apparatus and ROS formation. Algal cells were exposed to gamma radiation (0.49-1677mGy/h) for 6h and chlorophyll fluorescence parameters obtained by PAM fluorometry, while two fluorescent probes carboxy-H 2 DFFDA and DHR 123 were used for the quantification of ROS. The alterations seen in functional parameters of C. reinhardtii PSII after 6h of exposure to gamma radiation showed modifications of PSII energy transfer associated with electron transport and energy dissipation pathways, especially at the higher dose rates used. Results also showed that gamma radiation induced ROS in a dose-dependent manner under both light and dark conditions. The observed decrease in photosynthetic efficiency seems to be connected to the formation of ROS and can potentially lead to oxidative stress and cellular damage in chloroplasts. To our knowledge, this is the first report on changes in several chlorophyll fluorescence parameters associated with photosynthetic performance and ROS formation in microalgae after exposure to gamma radiation. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Role of membrane Hsp70 in radiation sensitivity of tumor cells

    International Nuclear Information System (INIS)

    Murakami, Naoya; Kühnel, Annett; Schmid, Thomas E.; Ilicic, Katarina; Stangl, Stefan; Braun, Isabella S.; Gehrmann, Mathias; Molls, Michael; Itami, Jun; Multhoff, Gabriele

    2015-01-01

    The major stress-inducible heat shock protein 70 (Hsp70) is frequently overexpressed in the cytosol and integrated in the plasma membrane of tumor cells via lipid anchorage. Following stress such as non-lethal irradiation Hsp70 synthesis is up-regulated. Intracellular located Hsp70 is known to exert cytoprotective properties, however, less is known about membrane (m)Hsp70. Herein, we investigate the role of mHsp70 in the sensitivity towards irradiation in tumor sublines that differ in their cytosolic and/or mHsp70 levels. The isogenic human colon carcinoma sublines CX + with stable high and CX − with stable low expression of mHsp70 were generated by fluorescence activated cell sorting, the mouse mammary carcinoma sublines 4 T1 (4 T1 ctrl) and Hsp70 knock-down (4 T1 Hsp70 KD) were produced using the CRISPR/Cas9 system, and the Hsp70 down-regulation in human lung carcinoma sublines H1339 ctrl/H1339 HSF-1 KD and EPLC-272H ctrl/EPLC-272H HSF-1 KD was achieved by small interfering (si)RNA against Heat shock factor 1 (HSF-1). Cytosolic and mHsp70 was quantified by Western blot analysis/ELISA and flow cytometry; double strand breaks (DSBs) and apoptosis were measured by flow cytometry using antibodies against γH2AX and real-time PCR (RT-PCR) using primers and antibodies directed against apoptosis related genes; and radiation sensitivity was determined using clonogenic cell surviving assays. CX + /CX − tumor cells exhibited similar cytosolic but differed significantly in their mHsp70 levels, 4 T1 ctrl/4 T1 Hsp70 KD cells showed significant differences in their cytosolic and mHsp70 levels and H1339 ctrl/H1339 HSF-1 KD and EPLC-272H ctrl/EPLC-272H HSF-1 KD lung carcinoma cell sublines had similar mHsp70 but significantly different cytosolic Hsp70 levels. γH2AX was significantly up-regulated in irradiated CX − and 4 T1 Hsp70 KD with low basal mHsp70 levels, but not in their mHsp70 high expressing counterparts, irrespectively of their cytosolic Hsp70 content. After

  17. Cooperation between human cells sensitive to UVA radiations: a clue to the mechanism of cellular hypersensitivity associated with different clinical conditions

    International Nuclear Information System (INIS)

    Francis, A.J.; Giannelli, F.

    1991-01-01

    Six fibroblast strains sensitive to long wavelength ultraviolet radiation (UVA) and one control strain were used to see if cooperation between the different cell strains could modify the abnormally high yield of single-strand DNA breaks (SSB) in the sensitive strains caused by UVA irradiation in complete Dulbecco's MEM. The sensitive strains were established from individuals showing proneness to different types of light-induced skin damage (actinic reticuloid, familial actinic keratoses with internal malignancies, and unusual frequency of basal cell carcinomata). When sensitive and normal cells were cocultivated, the UVA-induced SSB decreased in the sensitive cells and increased in the normal ones by amounts proportional to the ratio of the two types of cells in the mixtures. Furthermore the regression of SSB, in the sensitive cells, on the proportion of normal cells in the mixture extrapolated to normal levels of SSB when the proportion of normal cells increased to one. Cocultivation of different sensitive cells did not reduce the UVA-induced SSB to levels below those of the less sensitive cell strains. From these results we conclude that substances, present in limiting amounts, even in normal cells, can be transferred from cell to cell, presumably by metabolic cooperation, and modify the yield of SSB caused by UVA radiation. The abnormal yields of SSB in the sensitive cells appear to be entirely attributable to deficits in the substances responsible for the intercellular cooperation. We suggest that such substances are small molecular weight scavengers of active oxygen species

  18. Production and characterization of radiation-sensitive meiotic mutants of Coprinus cinereus

    International Nuclear Information System (INIS)

    Zolan, M.E.; Tremel, C.J.; Pukkila, P.J.

    1988-01-01

    We have isolated four gamma-sensitive mutants of the basidiomycete Coprinus cinereus. When homozygous, two of these (rad 3-1 and rad 9-1) produce fruiting bodies with very few viable basidiospores, the products of meiosis in this organism. A less radiation-sensitive allele of RAD 3, rad 3-2, causes no apparent meiotic defect in homozygous strains. Quantitative measurements of oidial survival of rad 3-1;rad 9-1 double mutants compared to the single mutants indicated that rad 3-1 and rad 9-1 mutants are defective in the same DNA repair pathway. In the pew viable basidiospores that are produced by these two strains, essentially normal levels of meiotic recombination can be detected. None of the mutants exhibits increased sensitivity to UV radiation. Cytological examination of meiotic chromosomes from mutant and wild-type fruiting bodies showed that rad 3-1 homozygous strains fail to condense and pair homologous chromosomes during prophase I. Although rad 9-1 strains are successful at chromosome pairing, meiosis is usually not completed in these mutants

  19. Effects of food diets on insect development and its sensitivity to gamma radiation

    International Nuclear Information System (INIS)

    Khattak, S.U.; Azhar, A.; Shahid, M.

    2004-01-01

    Taking red flour beetle, Tribolium castaneum (Herbst), as a study case, studies on the effect of different food diets on insect development and losses and its sensitivity to gamma radiation, were conducted under controlled laboratory conditions. The results revealed that all the three major parameters (development, losses and sensitivity) varied significantly (P< 0.05) with respect to fed diet. Developmental period was highest (43.5 days) in wheat starch and lowest (22 days) in wheat flour + 5% yeast (Standard diet). A significantly highest progeny (948) was produced in barley and lowest (105.3) in wheat starch. Maximum adult weight (37.35 mg/20 adults) was recorded in sorghum and minimum (33.4) in starch. Percent weight loss was highest (21.25) in barley and lowest (8.0) in starch. Barley flour was found as the most preferred diet. Radiosensitivity in relation to diet indicated that adults reared on wheat starch were most sensitive. Comparing the dose response, insect mortality was dose, diet and post irradiation duration dependent. However, 2.5kGy proved quite lethal. No significant effect of radiation was observed on moisture and protein contents of the diets, except reducing sugars. (author)

  20. Sensitivity to radiation and cycle-active drugs as a function of stem cell compartment repletion

    International Nuclear Information System (INIS)

    Degowin, R.L.; Gibson, D.P.

    1976-01-01

    We have studied the sensitivity of normal mouse hemopoietic tissue to radiation and cycle-active drugs in relation to stem cell compartment repletion. Recovery of erythropoiesis in endogenous spleen colonies, blood reticulocytes, and 30-day survivals were determined in mice after an initial large dose of partial-body irradiation. We found that the normal stem cell compartment is more sensitive to cycle-independent modes of therapy, like radiation and cyclophosphamide, than it is to cycle-active agents like cytosine arabinoside and methotrexate. The depleted stem cell compartment exhibits marked sensitivity to cycle-independent agents but less to cycle-active agents, which, however, suppress its recovery more than they do the normal. The overshoot phase of recovery is relatively resistant to either cycle-independent or cycle-active agents. A reticulocytosis following a reticulocytopenia signals the overshoot phase of stem cell compartment recovery and relatively increased resistance. These findings may prove useful in designing chemotherapy regimens and in anticipating marrow recovery in planning for supportive care in patients with neoplastic disease

  1. Temperature and hydration effects on absorbance spectra and radiation sensitivity of a radiochromic medium

    Energy Technology Data Exchange (ETDEWEB)

    Rink, Alexandra; Lewis, David F.; Varma, Sangya; Vitkin, I. Alex; Jaffray, David A. [Princess Margaret Hospital/Ontario Cancer Institute, Department of Medical Biophysics and Radiation Oncology, University of Toronto, Toronto, Ontario M5G 2M9 (Canada); Advanced Materials Group, International Specialty Products, Inc., Wayne, New Jersey 07470 (United States); Princess Margaret Hospital/Ontario Cancer Institute, Department of Medical Biophysics and Radiation Oncology, University of Toronto, Toronto, Ontario M5G 2M9 (Canada)

    2008-10-15

    The effects of temperature on real time changes in optical density ({Delta}OD) of GAFCHROMIC EBT film were investigated. The spectral peak of maximum change in absorbance ({lambda}{sub max}) was shown to downshift linearly when the temperature of the film was increased from 22 to 38 degree sign C. The {Delta}OD values were also shown to decrease linearly with temperature, and this decrease could not be attributed to the shift in {lambda}{sub max}. A compensation scheme using {lambda}{sub max} and a temperature-dependent correction factor was investigated, but provided limited improvement. Part of the reason may be the fluctuations in hydration of the active component, which were found to affect both position of absorbance peaks and the sensitivity of the film. To test the effect of hydration, laminated and unlaminated films were desiccated. This shifted both the major and minor absorbance peaks in the opposite direction to the change observed with temperature. The desiccated film also exhibited reduced sensitivity to ionizing radiation. Rehydration of the desiccated films did not reverse the effects, but rather gave rise to another form of the polymer with absorbance maxima upshifted further 20 nm. Hence, the spectral characteristics and sensitivity of the film can be dependent on its history, potentially complicating both real-time and conventional radiation dosimetry.

  2. Intervention of oxygen-control ability to radiation sensitivity, cell aging and cell transformation

    International Nuclear Information System (INIS)

    Yoshii, Hanako; Watanabe, Masami

    2009-01-01

    Oxygen is essential for life, and cells have therefore developed numerous adaptive responses to oxygen change. Here, we examined the difference in oxygen-control functions of human (HE), mouse (ME), and Syrian hamster embryo (SHE) cells cultured under different oxygen conditions (0.5%, 2% and 20%), and also examined whether oxygen tensions contributed to cellular lifespan and transformation. HE cells had their replicative lifespan slightly extended under hypoxic (0.5% and 2% oxygen) conditions, but were not immortalized under any of the oxygen concentrations. On the other hand, although ME cells cultured under 20% oxygen tension decreased their proliferation potency temporarily at early stage, all rodent cells were immortalized and acquired anchorage-independency, regardless of oxygen tension. These results suggest that cellular oxygen control function is related to sensitivities cellular immortalization and transformation. To understand intervention of oxygen control ability on cellular immortalization and transformation, we examined the intracellular oxidative level, mitochondria functions and radiation sensitivity. Intracellular oxidative levels of hypoxically cultured rodent cells were significantly enhanced. Mitochondrial membrane potential was altered depend on oxygen tensions, but the change was not parallel to mitochondria number in rodent cells. ME cells were particularly sensitive to oxygen change, and showed a clear oxygen effect on the X-ray survival. However, there was no difference in frequency of radiation-induced micronuclei between HE and ME cells. These results suggest that the response to oxygen change differs markedly in HE and rodent cells. (author)

  3. SU-F-T-678: Clotrimazole Sensitizes MCF-7 Breast Cancer Cell Line to Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, L; Tambasco, M [San Diego State University, San Diego, CA (United States)

    2016-06-15

    Purpose: To study the effects of Clotrimazole (CLT) on radiosensitivity of MCF-7 Cells in correlation to detachment of Hexokinase II from the Voltage Dependent Anion Channel on the outer membrane of the mitochondria. Apoptotic fractions were also analyzed in relation to the detachment of Hexokinase. Methods: This study focused on the mammary adenocarcinoma cell line, MCF-7. Colony forming assays were used to analyze radiosensitization by CLT. Flow cytometry methods were used to analyze apoptotic vs necrotic fractions after treatment with CLT. Spectrophotometery was used to analyze the mitochondrial bound and soluble fraction of Hexokinase by means of relative enzymatic activity. Results: Our preliminary data have shown that CLT sensitizes MCF-7 cells to radiation in a dose and incubation time dependent manner up. We have also demonstrated that there are two radiosensitizing periods in MCF-7 cells with the first corresponding to the cycle arrest after 24 hours observed in other cell lines. The second radiosensitizing period occurs with incubation in CLT after irradiation which reaches maximum effect around 24 hours of incubation time. Preliminary data from our Hexokinase detachment assay show a factor of two increase in the ratio of unbound to bound Hexokinase when comparing incubation for 24 hours in media containing 0 and 20 µM CLT. Conclusion: This study and others indicate CLT as a possible radiosensitizing agent in cancer therapies. While CLT itself shows toxicity to the liver in high doses, this study further demonstrates that disruption of the Warburg Effect and unbinding of mitochondrial bound Hexokinase as a possible pathway for cancer treatment.

  4. SU-F-T-678: Clotrimazole Sensitizes MCF-7 Breast Cancer Cell Line to Radiation

    International Nuclear Information System (INIS)

    Garcia, L; Tambasco, M

    2016-01-01

    Purpose: To study the effects of Clotrimazole (CLT) on radiosensitivity of MCF-7 Cells in correlation to detachment of Hexokinase II from the Voltage Dependent Anion Channel on the outer membrane of the mitochondria. Apoptotic fractions were also analyzed in relation to the detachment of Hexokinase. Methods: This study focused on the mammary adenocarcinoma cell line, MCF-7. Colony forming assays were used to analyze radiosensitization by CLT. Flow cytometry methods were used to analyze apoptotic vs necrotic fractions after treatment with CLT. Spectrophotometery was used to analyze the mitochondrial bound and soluble fraction of Hexokinase by means of relative enzymatic activity. Results: Our preliminary data have shown that CLT sensitizes MCF-7 cells to radiation in a dose and incubation time dependent manner up. We have also demonstrated that there are two radiosensitizing periods in MCF-7 cells with the first corresponding to the cycle arrest after 24 hours observed in other cell lines. The second radiosensitizing period occurs with incubation in CLT after irradiation which reaches maximum effect around 24 hours of incubation time. Preliminary data from our Hexokinase detachment assay show a factor of two increase in the ratio of unbound to bound Hexokinase when comparing incubation for 24 hours in media containing 0 and 20 µM CLT. Conclusion: This study and others indicate CLT as a possible radiosensitizing agent in cancer therapies. While CLT itself shows toxicity to the liver in high doses, this study further demonstrates that disruption of the Warburg Effect and unbinding of mitochondrial bound Hexokinase as a possible pathway for cancer treatment.

  5. Development of radiation-resisting high molecular-weight materials

    International Nuclear Information System (INIS)

    Nakagawa, Tsutomu

    1976-01-01

    The excellent radiation-resisting polyvinyl chloride developed at the opportunity of the research on the relationships between the protection of living body and the polymer-technological protection from radiation is reviewed. The report is divided into four main parts, namely 1) the change in the molecular arrangement of market-available, high molecular-weight materials by gamma-ray irradiation, 2) the protection of high molecular-weight materials from radiation, 3) the relationships between the biological radiation-protective substances and the change to radiation-resisting property of synthesized high molecular-weight substances, and 4) the development of the radiation-resisting high molecular-weight materials as metal-collecting agents. Attention is paid to the polyvinyl chloride having N-methyl-dithio-carbamate radical (PMD), synthesized by the author et. al., that has excellent radiation-resisting property. PMD has some possibility to form thiol- and amino-radicals necessary to protect living things from radiation. It is believed that the protection effects of N-methyl-dithio-carbamate radical are caused by the relatively stable S radical produced by the energy transfer. PMD film is suitable for the irradiation of foods, because it hardly changes the permeability of oxygen and carbon dioxide. PMD produces mercaptide or chelate. A new metal-collecting agent (PSDC) having reactivity with the metallic ions with radiation-resisting property was developed, which is derived from polyvinyl chloride and sodium N-methyl-N-carboxy-methyl-dithio-carbamate. (Iwakiri, K.)

  6. Radiation damage on high polymer epoxies

    Energy Technology Data Exchange (ETDEWEB)

    Pak, H M [Royal Military Coll. of Canada, Kingston, ON (Canada)

    1994-12-31

    The effect of irradiation in a SLOWPOKE-2 reactor on the adhesive strength of epoxy resins was studied using the ASTM D897 standard testing procedure. Although the results were variable, indicating the doses were not well defined, nevertheless, there was evidence of strengthening associated with radiation-induced crosslinking. 2 figs., 1 tab.

  7. Towards highly sensitive strain sensing based on nanostructured materials

    International Nuclear Information System (INIS)

    Dao, Dzung Viet; Nakamura, Koichi; Sugiyama, Susumu; Bui, Tung Thanh; Dau, Van Thanh; Yamada, Takeo; Hata, Kenji

    2010-01-01

    This paper presents our recent theoretical and experimental study of piezo-effects in nanostructured materials for highly sensitive, high resolution mechanical sensors. The piezo-effects presented here include the piezoresistive effect in a silicon nanowire (SiNW) and single wall carbon nanotube (SWCNT) thin film, as well as the piezo-optic effect in a Si photonic crystal (PhC) nanocavity. Firstly, the electronic energy band structure of the silicon nanostructure is discussed and simulated by using the First-Principles Calculations method. The result showed a remarkably different energy band structure compared with that of bulk silicon. This difference in the electronic state will result in different physical, chemical, and therefore, sensing properties of silicon nanostructures. The piezoresistive effects of SiNW and SWCNT thin film were investigated experimentally. We found that, when the width of ( 110 ) p-type SiNW decreases from 500 to 35 nm, the piezoresistive effect increases by more than 60%. The longitudinal piezoresistive coefficient of SWCNT thin film was measured to be twice that of bulk p-type silicon. Finally, theoretical investigations of the piezo-optic effect in a PhC nanocavity based on Finite Difference Time Domain (FDTD) showed extremely high resolution strain sensing. These nanostructures were fabricated based on top-down nanofabrication technology. The achievements of this work are significant for highly sensitive, high resolution and miniaturized mechanical sensors

  8. A study of using polythiol compounds and 2-ethyl-hexyl-acrylate with carbon tetrachloride as sensitizers for radiation vulcanization of natural rubber latex

    International Nuclear Information System (INIS)

    Polsuksiri, C.

    1989-01-01

    Experiments on using 3 different compounds of polythiol and an acrylate as sensitizer for radiation vulcanization were conducted. It was found that 1,4 butane diol propane tris-3-mercapto propionate showed the tendency to be a good sensitizer. The tensile strength of the rubber film prepared from the irradiated latex was found to be 14 MPa at sensitizer concentration of 1 phr and radiation dose of 45 kGy. As for 2-ethyl hexyl acrylate (2EHA), the maximum tensile strength of rubber film was found to be 23 MPa at concentration of 3 phr and radiation dose of 35 kGy. The mixture of 2 EHA and CCl 4 at various ratio was also used as sensitizer. The optimum ratio was found to be 5:1 at concentration of 6 phr and radiation dose of 15 kGy. The maximum tensile strength was as high as 25 MPa. The study also revealed that the radiation vulcanized latex with crosslink density of about 18x10 18 C.L./cm 3 would give the rubber film of highest tensile strength

  9. Chromosome Aberration on High Level Background Natural Radiation Areas

    International Nuclear Information System (INIS)

    Yanti-Lusiyanti; Zubaidah-Alatas

    2001-01-01

    When the body is irradiated, all cells can suffer cytogenetic damage that can be seen as structural damage of chromosome in the lymphocytes. People no matter where they live in world are exposed to background radiation from natural sources both internal and external such as cosmic radiation, terrestrial radiation, cosmogenic radiation radon and thoron. Level of area natural ionizing radiation is varies depending on the altitude, the soil or rock conditions, particular food chains and the building materials and construction features. Level of normal areas of background exposure is annual effective dose 2.4 mSv and the high level areas of background exposure 20 mSv. This paper discuses the frequency of aberration chromosome especially dysenteries in several countries having high level radiation background. It seems that frequency of chromosome aberrations increase, generally with the increase of age of the people and the accumulated dose received. (author)

  10. Anticoagulation and high dose liver radiation. A preliminary report

    International Nuclear Information System (INIS)

    Lightdale, C.J.; Wasser, J.; Coleman, M.; Brower, M.; Tefft, M.; Pasmantier, M.

    1979-01-01

    Two groups of patients were observed for evidence of acute radiation hepatitis during high dose radiation to the liver. The first group of 18 patients with metastatic liver disease received an average of 4,050 rad to the whole liver. Half received anticoagulation with warfarin. One patient on anticoagulation developed evidence of acute radiation hepatitis while 2 patients did so without anticoagulation. Eleven patients with Hodgkin's disease received 4,000 rad to the left lobe of the liver during extended field radiation. Four of these 11 patients were anticoagulated to therapeutic range. Only one of the fully anticoagulated patients showed changes on liver scan consistent with radiation hepatitis whereas three did so without anticoagulation. No serious sequelae from anticoagulation occurred in either group. These preliminary data suggest that anticoagulation may be safely administered with high dose hepatic radiation and that further trials with anticoagulation are warranted

  11. A two dimensional modeling study of the sensitivity of ozone to radiative flux uncertainties

    International Nuclear Information System (INIS)

    Grant, K.E.; Wuebbles, D.J.

    1988-08-01

    Radiative processes strongly effect equilibrium trace gas concentrations both directly, through photolysis reactions, and indirectly through temperature and transport processes. We have used the LLNL 2-D chemical-radiative-transport model to investigate the net sensitivity of equilibrium ozone concentrations to several changes in radiative forcing. Doubling CO 2 from 300 ppmv to 600 ppmv resulted in a temperature decrease of 5 K to 8 K in the middle stratosphere along with an 8% to 16% increase in ozone in the same region. Replacing our usual shortwave scattering algorithms with a simplified Rayleigh algorithm led to a 1% to 2% increase in ozone in the lower stratosphere. Finally, modifying our normal CO 2 cooling rates by corrections derived from line-by-line calculations resulted in several regions of heating and cooling. We observed temperature changes on the order of 1 K to 1.5 K with corresponding changes of 0.5% to 1.5% in O 3 . Our results for doubled CO 2 compare favorably with those by other authors. Results for our two perturbation scenarios stress the need for accurately modeling radiative processes while confirming the general validity of current models. 15 refs., 5 figs

  12. Radiation sensitization by dihydroartemisinin on human HeLa cells of cervical cancer

    International Nuclear Information System (INIS)

    Chen Xialin; Cao Jianping; Ji Rong; Zhu Wei; Liu Yang; Gong Xiaomei; Tang Yan; Pan Chunyan; Fan Saijun

    2009-01-01

    Objective: To investigate the radiosensitizing effects of dihydroartemisinin (DHA) on human HeLa cells of cervical cancer irradiated by X rays. Methods: Cell growth kinetics was determined using MTF assay. Cell survival was analyzed by elonogenic assay. The change of cell cycle and apeptosis was measured by flow cytometry. Results: Dihydroartemisinin inhibited the growth of HeLa cells of human cervical cancer and showed a dose-dependent and time-dependent manner. Dihydroartemisinin (20 μmol/L) showed the radiosensitizing effects on HeLa cells, and the sensitizing enhancement ratio (SER) was 1.47. Dihydroartemisinin abrogated radiation-induced G 2 arrest of the tested HeLa cells, the G 2 ratio of medicine + radiation group dechned from 73.58% to 48.31%. Dihydroartemisinin enhanced the apoptosis of HeLa cells by X-irradiation, the apoptosis rates of medicine + radiation group significantly increased from 29.46%, 48.04%, 70.21% to 45.79%, 66.36% and 79.58%, respectively for 2, 4 and 6 Gy. Conclusions: Dihydroartemisinin could increase the radiosensitivity of HeLa cells of human cervical cancer. Abrogation of radiation-induced C 2 arrest could be part of the mechanism. (authors)

  13. Radiation doses at high altitudes and during space flights

    International Nuclear Information System (INIS)

    Spurny, F.

    2001-01-01

    There are three main sources of radiation exposure during space flights and at high altitudes--galactic cosmic radiation, solar cosmic radiation and radiation of the earth's radiation belt. Their basic characteristics are presented in the first part of this paper.Man's exposure during space flights is discussed in the second part of the paper. Particular attention is devoted to the quantitative and qualitative characteristics of the radiation exposure on near-earth orbits: both theoretical estimation as well as experimental data are presented. Some remarks on radiation protection rules on-board space vehicles are also given.The problems connected with the radiation protection of air crew and passengers of subsonic and supersonic air transport are discussed in the last part of the paper. General characteristics of on-board radiation fields and their variations with flight altitude, geomagnetic parameters of a flight and the solar activity are presented, both based on theoretical estimates and experimental studies. The questions concerning air crew and passenger radiation protection arising after the publication of ICRP 60 recommendation are also discussed. Activities of different institutions relevant to the topic are mentioned; strategies to manage and check this type of radiation exposure are presented and discussed. Examples of results based on the author's personal experience are given, analyzed and discussed. (author)

  14. High sensitivity tests of the standard model for electroweak interactions

    International Nuclear Information System (INIS)

    Koetke, D.D.

    1992-01-01

    The work done on this project was focussed mainly on LAMPF experiment E969 known as the MEGA experiment, a high sensitivity search for the lepton family number violating decay μ → eγ to a sensitivity which, measured in terms of the branching ratio, BR = [μ→eγ]/[μ→e ν μ ν e ] ∼10 -13 is over two orders of magnitude better than previously reported values. The work done on MEGA during this period was divided between that done at Valparaiso University and that done at LAMPF. In addition, some contributions were made to a proposal to the LAMPF PAC to perform a precision measurement of the Michel ρ parameter, described below

  15. High sensitivity tests of the standard model for electroweak interactions

    International Nuclear Information System (INIS)

    1994-01-01

    The work done on this project focused on two LAMPF experiments. The MEGA experiment is a high-sensitivity search for the lepton family number violating decay μ → eγ to a sensitivity which, measured in terms of the branching ratio, BR = [μ → eγ]/[μ eν μ ν e ] ∼ 10 -13 , will be over two orders of magnitude better than previously reported values. The second is a precision measurement of the Michel ρ parameter from the positron energy spectrum of μ → eν μ ν e to test the predictions V-A theory of weak interactions. In this experiment the uncertainty in the measurement of the Michel ρ parameter is expected to be a factor of three lower than the present reported value. The detectors are operational, and data taking has begun

  16. High sensitivity tests of the standard model for electroweak interactions

    International Nuclear Information System (INIS)

    Koetke, D.D.; Manweiler, R.W.; Shirvel Stanislaus, T.D.

    1993-01-01

    The work done on this project was focused on two LAMPF experiments. The MEGA experiment, a high-sensitivity search for the lepton-family-number-violating decay μ → e γ to a sensitivity which, measured in terms of the branching ratio, BR = [μ → e γ]/[μ → ev μ v e ] ∼ 10 -13 , is over two orders of magnitude better than previously reported values. The second is a precision measurement of the Michel ρ parameter from the positron energy spectrum of μ → ev μ v e to test the V-A theory of weak interactions. The uncertainty in the measurement of the Michel ρ parameter is expected to be a factor of three lower than the present reported value

  17. High sensitive quench detection method using an integrated test wire

    International Nuclear Information System (INIS)

    Fevrier, A.; Tavergnier, J.P.; Nithart, H.; Kiblaire, M.; Duchateau, J.L.

    1981-01-01

    A high sensitive quench detection method which works even in the presence of an external perturbing magnetic field is reported. The quench signal is obtained from the difference in voltages at the superconducting winding terminals and at the terminals at a secondary winding strongly coupled to the primary. The secondary winding could consist of a ''zero-current strand'' of the superconducting cable not connected to one of the winding terminals or an integrated normal test wire inside the superconducting cable. Experimental results on quench detection obtained by this method are described. It is shown that the integrated test wire method leads to efficient and sensitive quench detection, especially in the presence of an external perturbing magnetic field

  18. Development of miniature γ dose rate monitor with high sensitivity

    International Nuclear Information System (INIS)

    Shi Huilu; Tuo Xianguo; Xi Dashun; Tang Rong; Mu Keliang; Yang Jianbo

    2009-01-01

    This paper introduces a miniature γ dose rate monitor with high sensitivity which design based on single chip microcomputer, it can continue monitoring γ dose rate and then choose wire or wireless communications to sent the monitoring data to host according to the actual conditions. It has two kinds of power supply system, AC power supply system and battery which can be chose by concrete circumstances. The design idea and implementation technology of hardware and software and the system structure of the monitor are detailed illustrated in this paper. The experimental results show that measurable range is 0.1 mR/h-200 mR/h, the sensitivity of γ is 90 cps/mR/h, dead time below 200 us, error of stability below ±10%. (authors)

  19. Polymer-Particle Pressure-Sensitive Paint with High Photostability

    Directory of Open Access Journals (Sweden)

    Yu Matsuda

    2016-04-01

    Full Text Available We propose a novel fast-responding and paintable pressure-sensitive paint (PSP based on polymer particles, i.e. polymer-particle (pp-PSP. As a fast-responding PSP, polymer-ceramic (PC-PSP is widely studied. Since PC-PSP generally consists of titanium (IV oxide (TiO2 particles, a large reduction in the luminescent intensity will occur due to the photocatalytic action of TiO2. We propose the usage of polymer particles instead of TiO2 particles to prevent the reduction in the luminescent intensity. Here, we fabricate pp-PSP based on the polystyrene particle with a diameter of 1 μm, and investigate the pressure- and temperature-sensitives, the response time, and the photostability. The performances of pp-PSP are compared with those of PC-PSP, indicating the high photostability with the other characteristics comparable to PC-PSP.

  20. Potential sensitivity of photosynthesis and isoprene emission to direct radiative effects of atmospheric aerosol pollution

    Science.gov (United States)

    Strada, Susanna; Unger, Nadine

    2016-04-01

    A global Earth system model is applied to quantify the impacts of direct anthropogenic aerosol effective radiative forcing on gross primary productivity (GPP) and isoprene emission. The impacts of different pollution aerosol sources (anthropogenic, biomass burning, and non-biomass burning) are investigated by performing sensitivity experiments. The model framework includes all known light and meteorological responses of photosynthesis, but uses fixed canopy structures and phenology. On a global scale, our results show that global land carbon fluxes (GPP and isoprene emission) are not sensitive to pollution aerosols, even under a global decline in surface solar radiation (direct + diffuse) by ˜ 9 %. At a regional scale, GPP and isoprene emission show a robust but opposite sensitivity to pollution aerosols in regions where forested canopies dominate. In eastern North America and Eurasia, anthropogenic pollution aerosols (mainly from non-biomass burning sources) enhance GPP by +5-8 % on an annual average. In the northwestern Amazon Basin and central Africa, biomass burning aerosols increase GPP by +2-5 % on an annual average, with a peak in the northwestern Amazon Basin during the dry-fire season (+5-8 %). The prevailing mechanism varies across regions: light scattering dominates in eastern North America, while a reduction in direct radiation dominates in Europe and China. Aerosol-induced GPP productivity increases in the Amazon and central Africa include an additional positive feedback from reduced canopy temperatures in response to increases in canopy conductance. In Eurasia and northeastern China, anthropogenic pollution aerosols drive a decrease in isoprene emission of -2 to -12 % on an annual average. Future research needs to incorporate the indirect effects of aerosols and possible feedbacks from dynamic carbon allocation and phenology.

  1. Potential sensitivity of photosynthesis and isoprene emission to direct radiative effects of atmospheric aerosol pollution

    Directory of Open Access Journals (Sweden)

    S. Strada

    2016-04-01

    Full Text Available A global Earth system model is applied to quantify the impacts of direct anthropogenic aerosol effective radiative forcing on gross primary productivity (GPP and isoprene emission. The impacts of different pollution aerosol sources (anthropogenic, biomass burning, and non-biomass burning are investigated by performing sensitivity experiments. The model framework includes all known light and meteorological responses of photosynthesis, but uses fixed canopy structures and phenology. On a global scale, our results show that global land carbon fluxes (GPP and isoprene emission are not sensitive to pollution aerosols, even under a global decline in surface solar radiation (direct + diffuse by  ∼ 9 %. At a regional scale, GPP and isoprene emission show a robust but opposite sensitivity to pollution aerosols in regions where forested canopies dominate. In eastern North America and Eurasia, anthropogenic pollution aerosols (mainly from non-biomass burning sources enhance GPP by +5–8 % on an annual average. In the northwestern Amazon Basin and central Africa, biomass burning aerosols increase GPP by +2–5 % on an annual average, with a peak in the northwestern Amazon Basin during the dry-fire season (+5–8 %. The prevailing mechanism varies across regions: light scattering dominates in eastern North America, while a reduction in direct radiation dominates in Europe and China. Aerosol-induced GPP productivity increases in the Amazon and central Africa include an additional positive feedback from reduced canopy temperatures in response to increases in canopy conductance. In Eurasia and northeastern China, anthropogenic pollution aerosols drive a decrease in isoprene emission of −2 to −12 % on an annual average. Future research needs to incorporate the indirect effects of aerosols and possible feedbacks from dynamic carbon allocation and phenology.

  2. Field test investigation of high sensitivity fiber optic seismic geophone

    Science.gov (United States)

    Wang, Meng; Min, Li; Zhang, Xiaolei; Zhang, Faxiang; Sun, Zhihui; Li, Shujuan; Wang, Chang; Zhao, Zhong; Hao, Guanghu

    2017-10-01

    Seismic reflection, whose measured signal is the artificial seismic waves ,is the most effective method and widely used in the geophysical prospecting. And this method can be used for exploration of oil, gas and coal. When a seismic wave travelling through the Earth encounters an interface between two materials with different acoustic impedances, some of the wave energy will reflect off the interface and some will refract through the interface. At its most basic, the seismic reflection technique consists of generating seismic waves and measuring the time taken for the waves to travel from the source, reflect off an interface and be detected by an array of geophones at the surface. Compared to traditional geophones such as electric, magnetic, mechanical and gas geophone, optical fiber geophones have many advantages. Optical fiber geophones can achieve sensing and signal transmission simultaneously. With the development of fiber grating sensor technology, fiber bragg grating (FBG) is being applied in seismic exploration and draws more and more attention to its advantage of anti-electromagnetic interference, high sensitivity and insensitivity to meteorological conditions. In this paper, we designed a high sensitivity geophone and tested its sensitivity, based on the theory of FBG sensing. The frequency response range is from 10 Hz to 100 Hz and the acceleration of the fiber optic seismic geophone is over 1000pm/g. sixteen-element fiber optic seismic geophone array system is presented and the field test is performed in Shengli oilfield of China. The field test shows that: (1) the fiber optic seismic geophone has a higher sensitivity than the traditional geophone between 1-100 Hz;(2) The low frequency reflection wave continuity of fiber Bragg grating geophone is better.

  3. A CMOS In-Pixel CTIA High Sensitivity Fluorescence Imager.

    Science.gov (United States)

    Murari, Kartikeya; Etienne-Cummings, Ralph; Thakor, Nitish; Cauwenberghs, Gert

    2011-10-01

    Traditionally, charge coupled device (CCD) based image sensors have held sway over the field of biomedical imaging. Complementary metal oxide semiconductor (CMOS) based imagers so far lack sensitivity leading to poor low-light imaging. Certain applications including our work on animal-mountable systems for imaging in awake and unrestrained rodents require the high sensitivity and image quality of CCDs and the low power consumption, flexibility and compactness of CMOS imagers. We present a 132×124 high sensitivity imager array with a 20.1 μm pixel pitch fabricated in a standard 0.5 μ CMOS process. The chip incorporates n-well/p-sub photodiodes, capacitive transimpedance amplifier (CTIA) based in-pixel amplification, pixel scanners and delta differencing circuits. The 5-transistor all-nMOS pixel interfaces with peripheral pMOS transistors for column-parallel CTIA. At 70 fps, the array has a minimum detectable signal of 4 nW/cm(2) at a wavelength of 450 nm while consuming 718 μA from a 3.3 V supply. Peak signal to noise ratio (SNR) was 44 dB at an incident intensity of 1 μW/cm(2). Implementing 4×4 binning allowed the frame rate to be increased to 675 fps. Alternately, sensitivity could be increased to detect about 0.8 nW/cm(2) while maintaining 70 fps. The chip was used to image single cell fluorescence at 28 fps with an average SNR of 32 dB. For comparison, a cooled CCD camera imaged the same cell at 20 fps with an average SNR of 33.2 dB under the same illumination while consuming over a watt.

  4. GIOVE: a new detector setup for high sensitivity germanium spectroscopy at shallow depth

    International Nuclear Information System (INIS)

    Heusser, G.; Weber, M.; Hakenmüller, J.; Laubenstein, M.; Lindner, M.; Maneschg, W.; Simgen, H.; Stolzenburg, D.; Strecker, H.

    2015-01-01

    We report on the development and construction of the high-purity germanium spectrometer setup GIOVE (Germanium Inner Outer VEto), recently built and now operated at the shallow underground laboratory of the Max-Planck-Institut für Kernphysik, Heidelberg. Particular attention was paid to the design of a novel passive and active shield, aiming at efficient rejection of environmental and muon induced radiation backgrounds. The achieved sensitivity level of ≤100 μBq kg -1 for primordial radionuclides from U and Th in typical γ ray sample screening measurements is unique among instruments located at comparably shallow depths and can compete with instruments at far deeper underground sites

  5. GIOVE: a new detector setup for high sensitivity germanium spectroscopy at shallow depth

    Energy Technology Data Exchange (ETDEWEB)

    Heusser, G.; Weber, M.; Hakenmueller, J.; Lindner, M.; Maneschg, W.; Simgen, H.; Stolzenburg, D.; Strecker, H. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Laubenstein, M. [Laboratori Nazionali del Gran Sasso, Assergi (Italy)

    2015-11-15

    We report on the development and construction of the high-purity germanium spectrometer setup GIOVE (Germanium Inner Outer VEto), recently built and now operated at the shallow underground laboratory of the Max-Planck-Institut fuer Kernphysik, Heidelberg. Particular attention was paid to the design of a novel passive and active shield, aiming at efficient rejection of environmental and muon induced radiation backgrounds. The achieved sensitivity level of ≤ 100μBq kg{sup -1} for primordial radionuclides from U and Th in typical γ ray sample screening measurements is unique among instruments located at comparably shallow depths and can compete with instruments at far deeper underground sites. (orig.)

  6. Calibration of high-dose radiation facilities (Handbook)

    International Nuclear Information System (INIS)

    Gupta, B.L.; Bhat, R.M.

    1986-01-01

    In India at present several high intensity radiation sources are used. There are 135 teletheraphy machines and 65 high intensity cobalt-60 sources in the form of gamma chambers (2.5 Ci) and PANBIT (50 Ci). Several food irradiation facilities and a medical sterilization plant ISOMED are also in operation. The application of these high intensity sources involve a wide variation of dose from 10 Gy to 100 kGy. Accurate and reproducible radiation dosimetry is essential in the use of these sources. This handbook is especially compiled for calibration of high-dose radiation facilities. The first few chapters discuss such topics as interaction of radiation with matter, radiation chemistry, radiation processing, commonly used high intensity radiation sources and their special features, radiation units and dosimetry principles. In the chapters which follow, chemical dosimeters are discussed in detail. This discussion covers Fricke dosimeter, FBX dosimeter, ceric sulphate dosimeter, free radical dosimetry, coloured indicators for irrdiation verification. A final chapter is devoted to practical hints to be followed in calibration work. (author)

  7. Highly sensitive detection of urinary cadmium to assess personal exposure

    Energy Technology Data Exchange (ETDEWEB)

    Argun, Avni A.; Banks, Ashley M.; Merlen, Gwendolynne; Tempelman, Linda A. [Giner, Inc., 89 Rumford Ave., Newton 02466, MA United States (United States); Becker, Michael F.; Schuelke, Thomas [Fraunhofer USA – CCL, 1449 Engineering Research Ct., East Lansing 48824, MI (United States); Dweik, Badawi M., E-mail: bdweik@ginerinc.com [Giner, Inc., 89 Rumford Ave., Newton 02466, MA United States (United States)

    2013-04-22

    Highlights: ► An electrochemical sensor capable of detecting cadmium at parts-per-billion levels in urine. ► A novel fabrication method for Boron-Doped Diamond (BDD) ultramicroelectrode (UME) arrays. ► Unique combination of BDD UME arrays and a differential pulse voltammetry algorithm. ► High sensitivity, high reproducibility, and very low noise levels. ► Opportunity for portable operation to assess on-site personal exposure. -- Abstract: A series of Boron-Doped Diamond (BDD) ultramicroelectrode arrays were fabricated and investigated for their performance as electrochemical sensors to detect trace level metals such as cadmium. The steady-state diffusion behavior of these sensors was validated using cyclic voltammetry followed by electrochemical detection of cadmium in water and in human urine to demonstrate high sensitivity (>200 μA ppb{sup −1} cm{sup −2}) and low background current (<4 nA). When an array of ultramicroelectrodes was positioned with optimal spacing, these BDD sensors showed a sigmoidal diffusion behavior. They also demonstrated high accuracy with linear dose dependence for quantification of cadmium in a certified reference river water sample from the U.S. National Institute of Standards and Technology (NIST) as well as in a human urine sample spiked with 0.25–1 ppb cadmium.

  8. Extraordinary radiation super-sensitivity accompanying with sorafenib combination therapy: what lies beneath?

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ja Young; Lee, Ju Hye; Yoon, Han Bin; Lee, Ho Jeong; Jeon, Ho Sang; Nam, Ji Ho [Dept. of Radiation Oncology, Pusan National University Yangsan Hospital, Yangsan (Korea, Republic of)

    2017-06-15

    Primary liver tumor, especially hepatocellular carcinoma (HCC), is a common cause of cancer death worldwide. The incidence is generally higher in Asian countries than in western countries. Carcinogenesis of HCC is often associated with hepatitis viral infections. Current standard treatment of HCC is surgical resection or transplantation in patients with early stage disease. However, the patient with advanced stage disease, surgical resection is often limited. Sorafenib or other treatment modalities are not so effective as well. We report a case of unusual radiation super-sensitivity in advanced stage HCC, and review the literature.

  9. Method of shaping of direction-characterization of sensitivity of ionizing radiation detection probe

    International Nuclear Information System (INIS)

    Czarnecki, J.; Jaszczuk, J.; Kruczyk, M.; Slapa, M.; Wroblewski, T.

    1986-01-01

    A method of shaping of direction-characterization of sensitivity of the ionizing radiation detection probe, especially equipped with small gamma detectors is described. Two detectors are placed coaxially in the bases of the cylindrical shield. One of them is uncovered in the highest degree and the second is not covered to a maximum. The signals from them are processed on the standarized sequences of electrical impulses (taking into account the heights and the widths of the amplitude). 2 figs., 1 tab. (A.S.)

  10. Radiation interactions in high-pressure gases

    International Nuclear Information System (INIS)

    Christophorou, L.G.

    1990-01-01

    This article is on basic radiation interaction processes in dense fluids and on interphase studies aiming at the interfacing of knowledge on radiation interaction processes in the gaseous and the liquid state of matter. It is specifically focused on the effect of the density and nature of the medium on electron production in irradiated fluids and on the state, energy, transport, and attachment of slow excess electrons in dense fluids especially dielectric liquids which possess excess-electron conduction bands (V 0 < 0 eV). Studies over the past two decades have shown that the interactions of low-energy electrons with molecules embedded in dense media depend not only on the molecules themselves and their internal state of excitation, but also on the electron state and energy in -- and the nature and density of -- the medium in which the interactions occur

  11. Radiation interactions in high-pressure gases

    Energy Technology Data Exchange (ETDEWEB)

    Christophorou, L.G. (Oak Ridge National Lab., TN (USA) Tennessee Univ., Knoxville, TN (USA))

    1990-01-01

    This article is on basic radiation interaction processes in dense fluids and on interphase studies aiming at the interfacing of knowledge on radiation interaction processes in the gaseous and the liquid state of matter. It is specifically focused on the effect of the density and nature of the medium on electron production in irradiated fluids and on the state, energy, transport, and attachment of slow excess electrons in dense fluids especially dielectric liquids which possess excess-electron conduction bands (V{sub 0} < 0 eV). Studies over the past two decades have shown that the interactions of low-energy electrons with molecules embedded in dense media depend not only on the molecules themselves and their internal state of excitation, but also on the electron state and energy in -- and the nature and density of -- the medium in which the interactions occur.

  12. Origin of the effects of cell cycle age on radiation sensitivity

    International Nuclear Information System (INIS)

    Nelson, J.M.; Braby, L.A.; Metting, N.F.; Roesch, W.C.

    1987-01-01

    The observed differences in radiation sensitivity as a function of cell age could reflect either differences in cellular capacity to remove different types of damage, or differences in damage production. The authors used centrifugal elutriation methods to produce enriched populations of G/sub 1/-, S-, and G/sub 2/-phase cells from stationary phase CHO cultures. Recognizing the imperfect correlation between cell age and cross-sectional area (the criterion upon which the separation process is based) flow-cytometric methods were used to measure cellular DNA content and determine cell age distributions. Split-dose repair kinetics were then determined for cells in different phases of the cycle. The authors find no striking differences in total repair, indicating that damage is removed at generally the same rate and with essentially the same efficiency, throughout the cell cycle. This suggests that changes in the production of damage are likely responsible for the change in sensitivity

  13. Radiation vulcanization of natural rubber latex using irradiation n-butyl acrylate aqueous emulsion as sensitizer

    International Nuclear Information System (INIS)

    Vo Van Thien; Nguyen Quoc Hien; Keizo Makuuchi; Fumio Yoshii

    2000-01-01

    Natural rubber latex was vulcanized by gamma radiation with n-butyl acrylate aqueous emulsion irradiated at dose of 1.5 kGy as sensitizer. The total solid content of latex increases on the irradiation dose. The viscosity of latex on the standing time was investigated and became stable after one month of storage. The gel content of latex films increasing with irradiation dose and attained more than 94% at dose of 10 kGy. Tensile strength of films reached the values of 31MPa; 30 Mpa and 25 Mpa at vulcanization doses of 20 kGy, 15 kGy and 8 kGy for the concentrations of sensitizer 7 phr, 9 phr and 13 phr respectively. Elongation at break decreases as increasing dose. Tear strength of rubber films was from 30-40 N/mm. The tackiness of latex films decreases and smell of vulcanized latex is almost negligible. (author)

  14. Comparison of radiation sensitivity for three cell lines as measured by the cloning assay and the micro-nucleus test

    NARCIS (Netherlands)

    Stap, J.; Aten, J. A.

    1990-01-01

    The correlation between cell killing and the induction of micro-nuclei was studied for three cell lines after treatment with gamma radiation to investigate whether the frequency of micro-nucleated cells can be used to determine the radiation sensitivity of a cell type. R1 rat rhabdomyosarcoma cells

  15. Development of a model system to study leukotriene-induced modification of radiation sensitivity in mammalian cells

    Energy Technology Data Exchange (ETDEWEB)

    Walden, Jr, T L; Holahan, Jr, E V; Catravas, G N

    1986-01-01

    Leukotrienes (LT) are an important class of biological mediators for which no information exists concerning their synthesis following a radiation insult or on their ability to modify cellular response to a subsequent radiation exposure. Results are presented which illustrate that the Chinese hamster lung fibroblast cell line, V79A03, is useful as a model system to study the metabolic fate of leukotrienes and the effect of LT on radiation sensitivity of mammalian cells in vitro. (U.K.).

  16. Compton imaging with a highly-segmented, position-sensitive HPGe detector

    Energy Technology Data Exchange (ETDEWEB)

    Steinbach, T.; Hirsch, R.; Reiter, P.; Birkenbach, B.; Bruyneel, B.; Eberth, J.; Hess, H.; Lewandowski, L. [Universitaet zu Koeln, Institut fuer Kernphysik, Koeln (Germany); Gernhaeuser, R.; Maier, L.; Schlarb, M.; Weiler, B.; Winkel, M. [Technische Universitaet Muenchen, Physik Department, Garching (Germany)

    2017-02-15

    A Compton camera based on a highly-segmented high-purity germanium (HPGe) detector and a double-sided silicon-strip detector (DSSD) was developed, tested, and put into operation; the origin of γ radiation was determined successfully. The Compton camera is operated in two different modes. Coincidences from Compton-scattered γ-ray events between DSSD and HPGe detector allow for best angular resolution; while the high-efficiency mode takes advantage of the position sensitivity of the highly-segmented HPGe detector. In this mode the setup is sensitive to the whole 4π solid angle. The interaction-point positions in the 36-fold segmented large-volume HPGe detector are determined by pulse-shape analysis (PSA) of all HPGe detector signals. Imaging algorithms were developed for each mode and successfully implemented. The angular resolution sensitively depends on parameters such as geometry, selected multiplicity and interaction-point distances. Best results were obtained taking into account the crosstalk properties, the time alignment of the signals and the distance metric for the PSA for both operation modes. An angular resolution between 13.8 {sup circle} and 19.1 {sup circle}, depending on the minimal interaction-point distance for the high-efficiency mode at an energy of 1275 keV, was achieved. In the coincidence mode, an increased angular resolution of 4.6 {sup circle} was determined for the same γ-ray energy. (orig.)

  17. Radiation sensitivity of Salmonella isolates relative to resistance to ampicillin, chloramphenicol or gentamicin

    Science.gov (United States)

    Niemira, Brendan A.; Lonczynski, Kelly A.; Sommers, Christopher H.

    2006-09-01

    Antibiotic resistance of inoculated bacteria is a commonly used selective marker. Bacteria resistant to the antibiotic nalidixic acid have been shown to have an increased sensitivity to irradiation. The purpose of this research was to screen a collection of Salmonella isolates for antibiotic resistance and determine the association, if any, of antibiotic resistance with radiation sensitivity. Twenty-four clinical isolates of Salmonella were screened for native resistance to multiple concentrations of ampicillin (Amp), chloramphenicol (Chl), or gentamicin (Gm). Test concentrations were chosen based on established clinical minimum inhibitory concentration (MIC) levels, and isolates were classified as either sensitive or resistant based on their ability to grow at or above the MIC. Salmonella cultures were grown overnight at (37 °C) in antibiotic-amended tryptic soy broth (TSB). Native resistance to Gm was observed with each of the 24 isolates (100%). Eight isolates (33%) were shown to be resistant to Amp, while seven isolates (29%) were shown to be resistant to Chl. In separate experiments, Salmonella cultures were grown overnight (37 °C) in TSB, centrifuged, and the cell pellets were re-suspended in phosphate buffer. The samples were then gamma irradiated at doses up to 1.0 kGy. The D10 values (the ionizing radiation dose required to reduce the viable number of microorganisms by 90%) were determined for the 24 isolates and they ranged from 0.181 to 0.359 kGy. No correlation was found between the D10 value of the isolate and its sensitivity or resistance to each of the three antibiotics. Resistance to Amp or Chl is suggested as appropriate resistance marker for Salmonella test strains to be used in studies of irradiation.

  18. Radiation sensitivity of Salmonella isolates relative to resistance to ampicillin, chloramphenicol or gentamicin

    International Nuclear Information System (INIS)

    Niemira, Brendan A.; Lonczynski, Kelly A.; Sommers, Christopher H.

    2006-01-01

    Antibiotic resistance of inoculated bacteria is a commonly used selective marker. Bacteria resistant to the antibiotic nalidixic acid have been shown to have an increased sensitivity to irradiation. The purpose of this research was to screen a collection of Salmonella isolates for antibiotic resistance and determine the association, if any, of antibiotic resistance with radiation sensitivity. Twenty-four clinical isolates of Salmonella were screened for native resistance to multiple concentrations of ampicillin (Amp), chloramphenicol (Chl), or gentamicin (Gm). Test concentrations were chosen based on established clinical minimum inhibitory concentration (MIC) levels, and isolates were classified as either sensitive or resistant based on their ability to grow at or above the MIC. Salmonella cultures were grown overnight at (37 o C) in antibiotic-amended tryptic soy broth (TSB). Native resistance to Gm was observed with each of the 24 isolates (100%). Eight isolates (33%) were shown to be resistant to Amp, while seven isolates (29%) were shown to be resistant to Chl. In separate experiments, Salmonella cultures were grown overnight (37 o C) in TSB, centrifuged, and the cell pellets were re-suspended in phosphate buffer. The samples were then gamma irradiated at doses up to 1.0 kGy. The D 10 values (the ionizing radiation dose required to reduce the viable number of microorganisms by 90%) were determined for the 24 isolates and they ranged from 0.181 to 0.359 kGy. No correlation was found between the D 10 value of the isolate and its sensitivity or resistance to each of the three antibiotics. Resistance to Amp or Chl is suggested as appropriate resistance marker for Salmonella test strains to be used in studies of irradiation

  19. High order effects in cross section sensitivity analysis

    International Nuclear Information System (INIS)

    Greenspan, E.; Karni, Y.; Gilai, D.

    1978-01-01

    Two types of high order effects associated with perturbations in the flux shape are considered: Spectral Fine Structure Effects (SFSE) and non-linearity between changes in performance parameters and data uncertainties. SFSE are investigated in Part I using a simple single resonance model. Results obtained for each of the resolved and for representative unresolved resonances of 238 U in a ZPR-6/7 like environment indicate that SFSE can have a significant contribution to the sensitivity of group constants to resonance parameters. Methods to account for SFSE both for the propagation of uncertainties and for the adjustment of nuclear data are discussed. A Second Order Sensitivity Theory (SOST) is presented, and its accuracy relative to that of the first order sensitivity theory and of the direct substitution method is investigated in Part II. The investigation is done for the non-linear problem of the effect of changes in the 297 keV sodium minimum cross section on the transport of neutrons in a deep-penetration problem. It is found that the SOST provides a satisfactory accuracy for cross section uncertainty analysis. For the same degree of accuracy, the SOST can be significantly more efficient than the direct substitution method

  20. Operationalization of the Russian Version of Highly Sensitive Person Scale

    Directory of Open Access Journals (Sweden)

    Регина Вячеславовна Ершова

    2018-12-01

    Full Text Available The aim of the present study was to operationalize a Russian version of the Highly Sensitive Person Scale (HSPS. The empirical data were collected in two ways: active, through oral advertising and inviting those who wish to take part in the study (snowball technique and passive (placement of ads about taking part in a research in social networks VKontakte and Facebook. As a result, 350 university students (117 men, 233 women, an average age of 18,2 (± 1,7 ap