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Sample records for doses 0-50 rad

  1. Dose Calibration of the ISS-RAD Fast Neutron Detector

    Science.gov (United States)

    Zeitlin, C.

    2015-01-01

    The ISS-RAD instrument has been fabricated by Southwest Research Institute and delivered to NASA for flight to the ISS in late 2015 or early 2016. ISS-RAD is essentially two instruments that share a common interface to ISS. The two instruments are the Charged Particle Detector (CPD), which is very similar to the MSL-RAD detector on Mars, and the Fast Neutron Detector (FND), which is a boron-loaded plastic scintillator with readout optimized for the 0.5 to 10 MeV energy range. As the FND is completely new, it has been necessary to develop methodology to allow it to be used to measure the neutron dose and dose equivalent. This talk will focus on the methods developed and their implementation using calibration data obtained in quasi-monoenergetic (QMN) neutron fields at the PTB facility in Braunschweig, Germany. The QMN data allow us to determine an approximate response function, from which we estimate dose and dose equivalent contributions per detected neutron as a function of the pulse height. We refer to these as the "pSv per count" curves for dose equivalent and the "pGy per count" curves for dose. The FND is required to provide a dose equivalent measurement with an accuracy of ?10% of the known value in a calibrated AmBe field. Four variants of the analysis method were developed, corresponding to two different approximations of the pSv per count curve, and two different implementations, one for real-time analysis onboard ISS and one for ground analysis. We will show that the preferred method, when applied in either real-time or ground analysis, yields good accuracy for the AmBe field. We find that the real-time algorithm is more susceptible to chance-coincidence background than is the algorithm used in ground analysis, so that the best estimates will come from the latter.

  2. Oak Ridge Reservation Environmental Protection Rad Neshaps Radionuclide Inventory Web Database and Rad Neshaps Source and Dose Database.

    Science.gov (United States)

    Scofield, Patricia A; Smith, Linda L; Johnson, David N

    2017-07-01

    The U.S. Environmental Protection Agency promulgated national emission standards for emissions of radionuclides other than radon from US Department of Energy facilities in Chapter 40 of the Code of Federal Regulations (CFR) 61, Subpart H. This regulatory standard limits the annual effective dose that any member of the public can receive from Department of Energy facilities to 0.1 mSv. As defined in the preamble of the final rule, all of the facilities on the Oak Ridge Reservation, i.e., the Y-12 National Security Complex, Oak Ridge National Laboratory, East Tennessee Technology Park, and any other U.S. Department of Energy operations on Oak Ridge Reservation, combined, must meet the annual dose limit of 0.1 mSv. At Oak Ridge National Laboratory, there are monitored sources and numerous unmonitored sources. To maintain radiological source and inventory information for these unmonitored sources, e.g., laboratory hoods, equipment exhausts, and room exhausts not currently venting to monitored stacks on the Oak Ridge National Laboratory campus, the Environmental Protection Rad NESHAPs Inventory Web Database was developed. This database is updated annually and is used to compile emissions data for the annual Radionuclide National Emission Standards for Hazardous Air Pollutants (Rad NESHAPs) report required by 40 CFR 61.94. It also provides supporting documentation for facility compliance audits. In addition, a Rad NESHAPs source and dose database was developed to import the source and dose summary data from Clean Air Act Assessment Package-1988 computer model files. This database provides Oak Ridge Reservation and facility-specific source inventory; doses associated with each source and facility; and total doses for the Oak Ridge Reservation dose.

  3. RISC-RAD. A European integrated approach to the problem of low doses

    International Nuclear Information System (INIS)

    Meunier, A.; Sabatier, L.; Atkinson, M.; Paretzke, H.; Bouffler, S.; Mullenders, L.

    2007-01-01

    Complete text of publication follows. Funded by the European Commission in the framework of a dedicated programme supporting research in the Nuclear sector (FP6 Euratom), the project RISC-RAD undertakes experimental and modelling studies ultimately to improve low dose radiation cancer risk assessment by exploring and providing evidence for the most appropriate radiation cancer risk projection and interpolation models. It started on 1st January 2004 and is running until 31 st October 2008. It mobilizes a consortium of 31 partners and is coordinated by Dr. Laure Sabatier from the French atomic energy commission. Indeed the project represents an unprecedented attempt to integrate horizontally the research on the effects of low doses of IR at the European level. A multipartner project supporting objective-driven research, RISC-RAD aims at contributing to bridge the remaining gap of scientific knowledge about effects of lows doses of ionizing radiation. It spans a large part of the research spectrum, including many topics addressed during the LOWRAD2007 conference. This presentation intends to give an account of the integrative aspects of the project, insights on the innovative solutions found to approach a complex and controversial scientific topic like the biological effects of low doses of ionizing radiation, and links with some areas of social studies on science.The concept of 'integration' implies the development of a new kind of activity in the research field, which crosses its traditional boundaries : controversies of several kinds must temporarily be overcome within the project management board in order to define and follow a common strategy. Among them, how to reconcile the creative part of fundamental research with the compliance to strict project planning rules has come up as a debate which questions the best way a significant collective and coordinated action can address the issue of the low dose cancer risk assessment on the long term. The knowledge and

  4. Low dose radiation effects: an integrative european approach (Risc-Rad Project) coordinated by the Cea

    International Nuclear Information System (INIS)

    Sabatier, L.

    2006-01-01

    RISC-RAD (Radiosensitivity of Individuals and Susceptibility to Cancer induced by ionizing Radiations) is an Integrated Project funded by the European Commission under 6. Framework Programme / EURATOM. RISC-RAD started on 1. January 2004 for a duration of four years. Coordinated by Cea (Dr Laure Sabatier), it involves 11 European countries (Austria, Denmark, Finland, France, Germany, Ireland, Italy, the Netherlands, Spain, Sweden and the United Kingdom) and 29 research institutions. Objectives: Exposures to low and protracted doses of ionizing radiation are very frequent in normal living environment, at work places, in industry and in medicine. Effects of these exposures on human health cannot be reliably assessed by epidemiological methods, nor is thoroughly understood by biologists. RISC-RAD project proposes to help bridging the gap of scientific knowledge about these effects. To achieve this goal, a necessary key step is to understand the basic mechanisms by which radiation induces cancer. Studying this multistage process in an integrated way, the project offers a new biological approach characterised by and clear-cut and objective-driven scientific policy: the project is focused on the effects of low doses (less than 100 mSv) and protracted doses of radiation. It aims at identifying new parameters that take into account the differences in radiation responses between individuals. A group of modelers works closely with the experimental teams in order to better quantify the risks associated with low and protracted doses. Research work is divided into five work packages interacting closely with each other. WP1 is dedicated to DNA damage. Ionizing Radiation (IR) produce a broad spectrum of base modifications and DNA strand breaks of different kinds, among which double-strand breaks and 'clustered damage' which is thought to be a major feature in biological effectiveness of IR. The aim of Work Package 1 is to improve understanding of the initial DNA damage induced by

  5. Development of dosimeters with rad-hard silicon diodes for high dose dosimetry

    International Nuclear Information System (INIS)

    Camargo, Fabio de

    2009-01-01

    In this work we report on results obtained with rad-hard Standard Float Zone (FZ), Diffusion Oxygenated Float Zone (DOFZ) and Magnetic Czochralski (MCz) silicon diodes in gamma radiation processing dosimetry. These p ± n-n + junction devices were manufactured by Okmetic Oyj. (Vantaa, Finland) and processed by the Microelectronics Center of Helsinki University of Technology in the framework of the CERN RD50 Collaboration. The dosimetric probes, based on FZ, DOFZ and M Cz devices, were designed to operate without bias voltage in the direct current mode as on-line radiation dosimeter. The irradiations were performed in the Radiation Technology Center (CTR) at IPEN-CNEN/SP using a 60 Co source (Gamma cell 220 - Nordion) with a dose rate around of 2.4 kGy/h. The current response of each diode was measured as a function of the exposure time in steps from 5 kGy up to 50 kGy to achieve a total absorbed dose of 275 kGy. The results obtained showed a significant decrease in the photocurrent generated in all devices for total absorbed doses higher than approximately 25 kGy. To reduce this effect, the samples were pre-irradiated with 60 Co gamma rays at 700 kGy in order to saturate the trap production in the diode's sensitive volume. After pre-irradiation, despite of being less sensitive, all devices exhibited more stable photocurrent signals, even for total absorbed doses of 275 kGy. To monitor possible gamma radiation damage effects produced on the diodes, their dynamic leakage current and capacitance were measured as a function of the absorbed dose. (author)

  6. MODELING THE VARIATIONS OF DOSE RATE MEASURED BY RAD DURING THE FIRST MSL MARTIAN YEAR: 2012–2014

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jingnan; Wimmer-Schweingruber, Robert F.; Heber, Bernd; Köhler, Jan; Appel, Jan K.; Böhm, Eckart; Böttcher, Stephan; Burmeister, Sönke; Lohf, Henning; Martin, Cesar [Institute of Experimental and Applied Physics, Christian-Albrechts-University, Kiel (Germany); Zeitlin, Cary [Southwest Research Institute, Earth, Oceans and Space Department, Durham, NH (United States); Rafkin, Scot; Hassler, Donald M.; Ehresmann, Bent [Southwest Research Institute, Space Science and Engineering Division, Boulder, CO (United States); Posner, Arik [NASA Headquarters, Science Mission Directorate, Washington, DC (United States); Brinza, David E. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA (United States); Kahanpää, H. [Finnish Meteorological Institute, Helsinki (Finland); Reitz, Günther, E-mail: guo@physik.uni-kiel.de [Aerospace Medicine, Deutsches Zentrum für Luft- und Raumfahrt, Köln (Germany)

    2015-09-01

    The Radiation Assessment Detector (RAD), on board Mars Science Laboratory’s (MSL) rover Curiosity, measures the energy spectra of both energetic charged and neutral particles along with the radiation dose rate at the surface of Mars. With these first-ever measurements on the Martian surface, RAD observed several effects influencing the galactic cosmic-ray (GCR) induced surface radiation dose concurrently: (a) short-term diurnal variations of the Martian atmospheric pressure caused by daily thermal tides, (b) long-term seasonal pressure changes in the Martian atmosphere, and (c) the modulation of the primary GCR flux by the heliospheric magnetic field, which correlates with long-term solar activity and the rotation of the Sun. The RAD surface dose measurements, along with the surface pressure data and the solar modulation factor, are analyzed and fitted to empirical models that quantitatively demonstrate how the long-term influences ((b) and (c)) are related to the measured dose rates. Correspondingly, we can estimate dose rate and dose equivalents under different solar modulations and different atmospheric conditions, thus allowing empirical predictions of the Martian surface radiation environment.

  7. Gamma and electron high dose dosimetry with rad-hard Si diodes

    International Nuclear Information System (INIS)

    Pascoalino, Kelly Cristina da Silva

    2014-01-01

    In this work the main dosimetric characteristics of rad-hard Float Zone (FZ) and magnetic Czochralski (MCz) diodes to electrons (1.5 MeV) and gamma ( 60 Co) radiation are evaluated. The dosimetric system proposed is based on electrical current measurements due to radiation interactions on the devices. The batch response uniformity was studied for the n-type FZ diodes irradiated with gamma rays. The coefficient of variation of the current measurement was about 1.25% at 5 kGy of accumulated dose. A sensitivity decrease with the increase of the accumulated dose (Total Ionizing Dose - TID) was observed for both FZ and MCz diodes. For gamma irradiation, these effect is more pronounced for n-type or smaller resistivity diodes. Two types of dosimetric probe were used on the electron irradiation procedures, one of them specially designed to avoid the deterioration of the electrical contacts and the diodes metallization. The sensitivity of the preirradiated FZ and MCz diodes fell about 10% and 40%, respectively, during electron irradiation at 1.25 MGy of accumulated dose. The effect of electron radiation damage on the electrical properties of the diodes was studied by the means of leakage current and capacitance measurements as a function of bias voltage. The leakage current increases with the accumulated dose but does not contributes significantly to the current signal, since the diodes are operated in photovoltaic mode, without bias voltage. For the MCz diode no change in the full depletion voltage was observed, which indicates its higher tolerance to radiation-induced damage, as expected. During electron irradiation the temperature increases and in order to determine its influence for the current signals, the leakage current values were extrapolated up to 35 °C. The contribution does not exceed 0.1% for FZ and MCz diodes. The effect of the radiation type, electrons or gamma rays, on the pre dose procedures was analyzed for the FZ n-type device and was observed that the

  8. A simple method to retrospectively estimate patient dose-area product for chest tomosynthesis examinations performed using VolumeRAD.

    Science.gov (United States)

    Båth, Magnus; Söderman, Christina; Svalkvist, Angelica

    2014-10-01

    The purpose of the present work was to develop and validate a method of retrospectively estimating the dose-area product (DAP) of a chest tomosynthesis examination performed using the VolumeRAD system (GE Healthcare, Chalfont St. Giles, UK) from digital imaging and communications in medicine (DICOM) data available in the scout image. DICOM data were retrieved for 20 patients undergoing chest tomosynthesis using VolumeRAD. Using information about how the exposure parameters for the tomosynthesis examination are determined by the scout image, a correction factor for the adjustment in field size with projection angle was determined. The correction factor was used to estimate the DAP for 20 additional chest tomosynthesis examinations from DICOM data available in the scout images, which was compared with the actual DAP registered for the projection radiographs acquired during the tomosynthesis examination. A field size correction factor of 0.935 was determined. Applying the developed method using this factor, the average difference between the estimated DAP and the actual DAP was 0.2%, with a standard deviation of 0.8%. However, the difference was not normally distributed and the maximum error was only 1.0%. The validity and reliability of the presented method were thus very high. A method to estimate the DAP of a chest tomosynthesis examination performed using the VolumeRAD system from DICOM data in the scout image was developed and validated. As the scout image normally is the only image connected to the tomosynthesis examination stored in the picture archiving and communication system (PACS) containing dose data, the method may be of value for retrospectively estimating patient dose in clinical use of chest tomosynthesis.

  9. A simple method to retrospectively estimate patient dose-area product for chest tomosynthesis examinations performed using VolumeRAD

    Energy Technology Data Exchange (ETDEWEB)

    Båth, Magnus, E-mail: magnus.bath@vgregion.se; Svalkvist, Angelica [Department of Radiation Physics, Institute of Clinical Sciences, The Sahlgrenska Academy at University of Gothenburg, Gothenburg SE-413 45, Sweden and Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg SE-413 45 (Sweden); Söderman, Christina [Department of Radiation Physics, Institute of Clinical Sciences, The Sahlgrenska Academy at University of Gothenburg, Gothenburg SE-413 45 (Sweden)

    2014-10-15

    Purpose: The purpose of the present work was to develop and validate a method of retrospectively estimating the dose-area product (DAP) of a chest tomosynthesis examination performed using the VolumeRAD system (GE Healthcare, Chalfont St. Giles, UK) from digital imaging and communications in medicine (DICOM) data available in the scout image. Methods: DICOM data were retrieved for 20 patients undergoing chest tomosynthesis using VolumeRAD. Using information about how the exposure parameters for the tomosynthesis examination are determined by the scout image, a correction factor for the adjustment in field size with projection angle was determined. The correction factor was used to estimate the DAP for 20 additional chest tomosynthesis examinations from DICOM data available in the scout images, which was compared with the actual DAP registered for the projection radiographs acquired during the tomosynthesis examination. Results: A field size correction factor of 0.935 was determined. Applying the developed method using this factor, the average difference between the estimated DAP and the actual DAP was 0.2%, with a standard deviation of 0.8%. However, the difference was not normally distributed and the maximum error was only 1.0%. The validity and reliability of the presented method were thus very high. Conclusions: A method to estimate the DAP of a chest tomosynthesis examination performed using the VolumeRAD system from DICOM data in the scout image was developed and validated. As the scout image normally is the only image connected to the tomosynthesis examination stored in the picture archiving and communication system (PACS) containing dose data, the method may be of value for retrospectively estimating patient dose in clinical use of chest tomosynthesis.

  10. A simple method to retrospectively estimate patient dose-area product for chest tomosynthesis examinations performed using VolumeRAD

    International Nuclear Information System (INIS)

    Båth, Magnus; Svalkvist, Angelica; Söderman, Christina

    2014-01-01

    Purpose: The purpose of the present work was to develop and validate a method of retrospectively estimating the dose-area product (DAP) of a chest tomosynthesis examination performed using the VolumeRAD system (GE Healthcare, Chalfont St. Giles, UK) from digital imaging and communications in medicine (DICOM) data available in the scout image. Methods: DICOM data were retrieved for 20 patients undergoing chest tomosynthesis using VolumeRAD. Using information about how the exposure parameters for the tomosynthesis examination are determined by the scout image, a correction factor for the adjustment in field size with projection angle was determined. The correction factor was used to estimate the DAP for 20 additional chest tomosynthesis examinations from DICOM data available in the scout images, which was compared with the actual DAP registered for the projection radiographs acquired during the tomosynthesis examination. Results: A field size correction factor of 0.935 was determined. Applying the developed method using this factor, the average difference between the estimated DAP and the actual DAP was 0.2%, with a standard deviation of 0.8%. However, the difference was not normally distributed and the maximum error was only 1.0%. The validity and reliability of the presented method were thus very high. Conclusions: A method to estimate the DAP of a chest tomosynthesis examination performed using the VolumeRAD system from DICOM data in the scout image was developed and validated. As the scout image normally is the only image connected to the tomosynthesis examination stored in the picture archiving and communication system (PACS) containing dose data, the method may be of value for retrospectively estimating patient dose in clinical use of chest tomosynthesis

  11. Early neuro-vegetative responses to head irradiation of the rabbit at mean absorbed doses of 1000 and 150 rads

    International Nuclear Information System (INIS)

    Dufour, Raymond.

    1977-10-01

    Head irradiation was studied in order to back up a previous assumption on the kinetics of vegetative responses to whole-body exposure: the earliest response might have a central origin and explain the slight increase of blood pressure, tachycardia, hyperthermia and hyperventilation. Following head exposure at a mean absorbed dose of 1000 rads, blood pressure increased on the 15 th min, reaching 0.8 - 1 cm Hg on the 30th min and during 7 - 8 hours. The increase of heart rate occured as early and was about 40% and lasted for 24 hours. Body temperature increased as early as the end of exposure, was highest within 2 - 2.30 hours and decreased on the 6th hour. Arterial blood showed a respiratory alkalosis on the 1st hour, lasting after the 6th hour and disappeared within 24 hours. At a dose of 150 rads, the changes were lasting but of lower importance and duration. The results show that early changes following whole-body exposure also occur after head exposure and are magnified. The kinetics involved are discussed [fr

  12. Dose characterization of the rad sourceTM 2400 X-ray irradiator for oyster pasteurization

    International Nuclear Information System (INIS)

    Wagner, Jennifer Koop; Dillon, Jeff A.; Blythe, Eugene K.; Ford, John R.

    2009-01-01

    The RS 2400's cylindrical X-ray source yields dose rates high enough to allow the irradiator to replace widely used gamma irradiators. Except for the leftmost 5 cm, beam uniformity is within 10% at the tube surface. At maximum operating parameters, the beam has HVL 1 =13.66 mm aluminum, HC=0.47, and hν eq =88.5 keV. Maximum dose rates to tissue are 65 Gy min -1 ±3.1% at tube surface, 37 Gy min -1 ±3.1% at center of canisters, 14.1 Gy min -1 ±6.5% for thin-shelled oysters, and 12.3 Gy min -1 ±6.2% for thick-shelled oysters

  13. The efficacy of hyperbaric oxygen in modifying the response of tissue to irradiation in doses of 200-400 rad per fraction

    International Nuclear Information System (INIS)

    Suit, D.D.; Orsi, L.

    1975-01-01

    The efficacy of respiration of O 2 at 30 psi in modifying the response of normal and tumour tissue to irradiation administered at 200 to 400 rad per fraction to anaesthetized mice has been evaluated. End-points have been delay in growth and TCD 50 for an early generation iso-transplant of a C 3 H mouse mammary carcinoma, and the acute reaction of skin of the C 3 H/Sed mouse. Results showed that the ratios of dose (air)/dose (O 2 30 psi) to elicit these end points were in the range 1.2 to 1.4. In earlier work using the same end points but doses per fraction 430 to 2100 rad, the ratios were 1.6 to 1.8. That is, for these tissue responses, respiration of O 2 at 30 psi increases the response of both normal and tumour tissue to all radiation doses tested. It is of greater effectiveness when combined with large doses per fraction, eg. greater than 430 rad. (author)

  14. Retrospective estimation of patient dose-area product in thoracic spine tomosynthesis performed using VolumeRAD

    International Nuclear Information System (INIS)

    Baath, Magnus; Svalkvist, Angelica; Soederman, Christina

    2016-01-01

    The aim of this study was to evaluate the use of a recently developed method of retrospectively estimating the patient dose-area product (DAP) of a chest tomosynthesis examination, performed using VolumeRAD, in thoracic spine tomosynthesis and to determine the necessary field-size correction factor. Digital imaging and communications in medicine (DICOM) data for the projection radiographs acquired during a thoracic spine tomosynthesis examination were retrieved directly from the modality for 17 patients. Using the previously developed method, an estimated DAP for the tomosynthesis examination was determined from DICOM data in the scout image. By comparing the estimated DAP with the actual DAP registered for the projection radiographs, a field-size correction factor was determined. The field-size correction factor for thoracic spine tomosynthesis was determined to 0.92. Applying this factor to the DAP estimated retrospectively, the maximum difference between the estimated DAP and the actual DAP was <3 %. In conclusion, the previously developed method of retrospectively estimating the DAP in chest tomosynthesis can be applied to thoracic spine tomosynthesis. (authors)

  15. Rad-by-rad (bit-by-bit): triumph of evidence over activities fostering fear of radiogenic cancers at low doses

    International Nuclear Information System (INIS)

    Strzelczyk, J.; Potter, W.; Zdrojewicz, Z.

    2006-01-01

    Full text: Large segments of Western population hold sciences in low esteem. This trend became particularly pervasive in the field of radiation sciences in recent decades. The resulting lack of knowledge, easily filled with fear that feeds on itself, makes people susceptible to prevailing dogmas. Decades-long moratorium on nuclear power in the US, resentment of a nything nuclear , delay/refusal to obtain medical radiation procedures are some of the societal consequences. The problem has been exacerbated by promulgation of the linear-no-threshold (LNT) dose response model by advisory bodies such as the ICRP, NCRP and others. This model assumes no safe level of radiation and implies that response is the same per unit dose regardless of the total dose or dose rate. The most recent (June 2005) report from the National Research Council, BEIR VII (Biological Effects of Ionizing Radiation) continues this approach and quantifies potential cancer risks at low doses by linear extrapolation of risk values obtained from epidemiological observations of populations exposed to high doses, 0.2 to 3 Sv. It minimizes significance of lack of evidence of adverse effects in populations exposed to low doses and discounts documented beneficial effects of low dose exposures on the human immune system. The LNT doctrine is in direct conflict with current findings of radiobiology and important features of modern radiation oncology. Fortunately, these aspects are addressed in-depth in another major report - issued jointly in March 2005 by two French Academies, of Sciences and of Medicine. The latter report is much less publicized thus it is a responsibility of radiation professionals, physicists, nuclear engineers, and physicians to become familiar with its content and relevant studies, and to widely disseminate this information. To counteract biased media, we need to be creative in developing means of sharing good news about radiation with co-workers, patients, and the general public

  16. Beyond mean pharyngeal constrictor dose for beam path toxicity in non-target swallowing muscles: dose-volume correlates of chronic radiation-associated dysphagia (RAD) after oropharyngeal intensity modulated radiotherapy

    Science.gov (United States)

    2016-01-01

    Purpose/Objective(s) We sought to identify swallowing muscle dose-response thresholds associated with chronic radiation-associated dysphagia (RAD) after IMRT for oropharyngeal cancer. Materials/Methods T1-4 N0-3 M0 oropharyngeal cancer patients who received definitive IMRT and systemic therapy were examined. Chronic RAD was coded as any of the following ≥ 12 months post-IMRT: videofluoroscopy/endoscopy detected aspiration or stricture, gastrostomy tube and/or aspiration pneumonia. DICOM-RT plan data were autosegmented using a custom region-of-interest (ROI) library and included inferior, middle and superior constrictors (IPC, MPC, and SPC), medial and lateral pterygoids (MPM, LPM), anterior and posterior digastrics (ADM, PDM), intrinsic tongue muscles (ITM), mylo/geniohyoid complex (MHM), genioglossus (GGM), ), masseter (MM), Buccinator (BM), palatoglossus (PGM), and cricopharyngeus (CPM), with ROI dose-volume histograms (DVHs) calculated. Recursive partitioning analysis (RPA) was used to identify dose-volume effects associated with chronic-RAD, for use in a multivariate (MV) model. Results Of 300 patients, 34 (11%) had chronic-RAD. RPA showed DVH-derived MHM V69 (i.e. the volume receiving ≥69Gy), GGM V35, ADM V60, MPC V49, and SPC V70 were associated with chronic-RAD. A model including age in addition to MHM V69 as continuous variables was optimal among tested MV models (AUC 0.835). Conclusion In addition to SPCs, dose to MHM should be monitored and constrained, especially in older patients (>62-years), when feasible. PMID:26897515

  17. Beyond mean pharyngeal constrictor dose for beam path toxicity in non-target swallowing muscles: Dose-volume correlates of chronic radiation-associated dysphagia (RAD) after oropharyngeal intensity modulated radiotherapy.

    Science.gov (United States)

    2016-02-01

    We sought to identify swallowing muscle dose-response thresholds associated with chronic radiation-associated dysphagia (RAD) after IMRT for oropharyngeal cancer. T1-4 N0-3 M0 oropharyngeal cancer patients who received definitive IMRT and systemic therapy were examined. Chronic RAD was coded as any of the following ⩾12months post-IMRT: videofluoroscopy/endoscopy detected aspiration or stricture, gastrostomy tube and/or aspiration pneumonia. DICOM-RT plan data were autosegmented using a custom region-of-interest (ROI) library and included inferior, middle and superior constrictors (IPC, MPC, and SPC), medial and lateral pterygoids (MPM, LPM), anterior and posterior digastrics (ADM, PDM), intrinsic tongue muscles (ITM), mylo/geniohyoid complex (MHM), genioglossus (GGM), masseter (MM), buccinator (BM), palatoglossus (PGM), and cricopharyngeus (CPM), with ROI dose-volume histograms (DVHs) calculated. Recursive partitioning analysis (RPA) was used to identify dose-volume effects associated with chronic-RAD, for use in a multivariate (MV) model. Of 300 patients, 34 (11%) had chronic-RAD. RPA showed DVH-derived MHM V69 (i.e. the volume receiving⩾69Gy), GGM V35, ADM V60, MPC V49, and SPC V70 were associated with chronic-RAD. A model including age in addition to MHM V69 as continuous variables was optimal among tested MV models (AUC 0.835). In addition to SPCs, dose to MHM should be monitored and constrained, especially in older patients (>62-years), when feasible. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  18. Neutron powder diffraction analysis of (Tm{sub 0.50}Ca{sub 0.50})MnO{sub 3} and (Lu{sub 0.50}Ca{sub 0.50})MnO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Martinelli, A., E-mail: alberto.martinelli@spin.cnr.it [SPIN-CNR, C.so Perrone 24, 16152 Genova (Italy); Ferretti, M. [SPIN-CNR, C.so Perrone 24, 16152 Genova (Italy); Universita degli Studi di Genova, Dipartimento di Chimica e Chimica Industriale, Via Dodecaneso 31, 16146 Genova (Italy); Cimberle, M.R. [IMEM-CNR, Via Dodecaneso 33, 16146, Genova (Italy); Ritter, C. [Institute Laue-Langevin, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9 (France)

    2012-12-15

    The crystal and magnetic structures of (Tm{sub 0.50}Ca{sub 0.50})MnO{sub 3} and (Lu{sub 0.50}Ca{sub 0.50})MnO{sub 3} have been investigated between 5 K and 300 K by means of high resolution neutron powder diffraction followed by Rietveld refinement and dc magnetic measurements. During cooling orbital ordering at the Mn sub-lattice takes place at T{sub OO}{approx}280 K in both compounds, inducing an orthorhombic to monoclinic phase transition. As the temperature is further decreased an antiferromagnetic CE-type structure occurs in both compounds at T{sub N}{approx}105 K. The comparison with other (Ln{sub 0.50}Ca{sub 0.50})MnO{sub 3} compounds reveals that at room temperature the average Jahn-Teller distortion increases sharply with the decrease of the ionic radius for lanthanides heavier than Sm. The ordered magnetic moment progressively decreases as the lanthanide ionic radius decreases on account of the decreased values of the Mn-O-Mn bond angles. - Graphical abstract: Rietveld refinement plot for (Tm{sub 0.50}Ca{sub 0.50})MnO{sub 3} obtained from neutron powder diffraction data collected at 5 K; the inset shows the CE-type spin ordering taking place at the Mn sub-lattice. Highlights: Black-Right-Pointing-Pointer The crystal and magnetic structures of (Tm{sub 0.50}Ca{sub 0.50})MnO{sub 3} and (Lu{sub 0.50}Ca{sub 0.50})MnO{sub 3} were analyzed by neutron powder diffraction. Black-Right-Pointing-Pointer Orbital ordering takes place below T{sub OO}{approx}280 K in both compounds. Black-Right-Pointing-Pointer An antiferromagnetic CE-type structure occurs in both compounds below T{sub N}{approx}105 K. Black-Right-Pointing-Pointer A Comparison with other (Ln{sub 0.50}Ca{sub 0.50})MnO{sub 3} compounds is reported.

  19. Dosimetric properties of the pocket alarm dosimeter type Alnor RAD 21L, RAD 21H, RAD 22

    International Nuclear Information System (INIS)

    Hauser, M.; Burgkhardt, B.; Piesch, E.

    1981-02-01

    In personnel monitoring pocket dosimeters with build-in alarm devices are increasingly in use. The report presents results of a test performed at Karlsruhe for the pocket dose and alarm meter type Alnor RAD 21L, RAD 21H, RAD 22. The properties investigated are above all linearity and reproducibility of the dose reading as well as of the acoustic alarm indication, dependence of the dose reading on the photon energy, the direction of the radiation incidence, the dose rate, the temperature, operational characteristic of the batteries. (orig.) [de

  20. Comparison of some aqueous chemical dosimeters for absorbed doses of less than 1000 rads. [Benzoic--salicylic acid, terephtalic--2-hydroxyterephtabe acid, ferrous sulfate--benzoic acid--xylenol orange, and standard Fricke dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Matthews, R W [Australian Atomic Energy Commission Research Establishment, Lucas Heights; Barker, N T; Sangster, D F

    1978-01-01

    This report gives the results of an investigation into the relative merits of the systems: benzoic-salicylic acid, terephthalic-2-hydroxyterephthalic acid, the more recent ferrous sulphate-benzoic acid-xylenol orange (FBX), and the standard Fricke dosimeter, for the measurement of absorbed doses under identical irradiation conditions, in the range 10 to 1000 rads.

  1. Investigations of the regulation of cerebral circulation by means of functional changes observed on unanaesthetized rabbits during hypoxia, paradoxical sleep and after whole-body γ-exposure (850-150 rad dose range)

    International Nuclear Information System (INIS)

    Dufour, Raymond.

    1977-01-01

    Both the general effects and the effects on cerebral circulation of whole-body exposure were studied at doses of 850, 650, 450, 250 and 150 rads. Early functional changes following exposure demonstrated two juxtaposed mechanisms, a central one and a peripheral one. The central process, slightly sensitive to the dose-effect, occurred earlier and should be at the origin of hyperthermia, hyperventilation, tachycardia, skin vasoconstruction and a slight increase of arterial pressure. The peripheral mechanisms, occurring slightly later should be more sensitive to the dose-effect and might be at the origin of hypothermic effects and cardiovascular depression. The increase of cerebral blood flow occurring at the 450 rad dose should be best explained by the presence of vasotropic substances. A twofold component of cerebral vasotonicity should be assumed that would depend on the autonomous nervous system and myogenous autoregulation [fr

  2. Effects of temperature and pressure on thermodynamic properties of Cd0.50 Zn0.50 Se alloy

    Science.gov (United States)

    Aarifeen, Najm ul; Afaq, A.

    2017-09-01

    Thermodynamic properties of \\text{C}{{\\text{d}}0.50} \\text{Z}{{\\text{n}}0.50} Se alloy are studied using quasi harmonic model for pressure range 0-10 GPa and temperature range 0-1000 K. The structural optimization is obtained by self consistent field calculations and full-potential linear muffin-tin orbital method with GGA+U as an exchange correlation functional where U=2.3427 eV is the hubbard potential. The effects of temperature and pressure on the bulk modulus, Helmholtz free energy, internal energy, entropy, Debye temperature, Grüneisen parameter, thermal expansion coefficient and heat capacities of the material are observed and discussed. The bulk modulus, Helmholtz free energy and Debye temperature are found to decrease with increasing temperature while there is an increasing behavior when the pressure rises. Whereas internal energy has increasing trend with rises in temperature and it almost remains insensitive to pressure. The entropy of the system increases (decreases) with a rise of pressure (temperature).

  3. Dose characterization of the rad source{sup TM} 2400 X-ray irradiator for oyster pasteurization

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Jennifer Koop [Department of Nuclear Engineering, Texas A and M University, College Station, TX 77843-3133 (United States)], E-mail: jenkoop@gmail.com; Dillon, Jeff A. [Experimental Seafood Processing Laboratory, Mississippi State University, Pascagoula, MS 39567 (United States); Blythe, Eugene K. [Coastal Research and Extension Center, Mississippi State University, South Mississippi Branch Experiment Station, Poplarville, MS 39470 (United States); Ford, John R. [Department of Nuclear Engineering, Texas A and M University, College Station, TX 77843-3133 (United States)

    2009-02-15

    The RS 2400's cylindrical X-ray source yields dose rates high enough to allow the irradiator to replace widely used gamma irradiators. Except for the leftmost 5 cm, beam uniformity is within 10% at the tube surface. At maximum operating parameters, the beam has HVL{sub 1}=13.66 mm aluminum, HC=0.47, and h{nu}{sub eq}=88.5 keV. Maximum dose rates to tissue are 65 Gy min{sup -1}{+-}3.1% at tube surface, 37 Gy min{sup -1}{+-}3.1% at center of canisters, 14.1 Gy min{sup -1}{+-}6.5% for thin-shelled oysters, and 12.3 Gy min{sup -1}{+-}6.2% for thick-shelled oysters.

  4. Temperature dependence of Raman scattering spectra of Basub(0.50)Srsub(0.50)Nbsub(2)Osub(6) crystal

    International Nuclear Information System (INIS)

    Gorelik, V.S.; Rustamov, Kh.Sh.; Kuz'minov, Yu.S.; Sushchinskij, M.M.

    1977-01-01

    The change of the Raman spectra in the crystal Basub(x)Srsub(1-x)Nbsub(2)Osub(6) (x=0.50) in the temperature range of 80-500 K has been studied. A conventional technique with the application of an argon laser (π=4880 A) and a diffraction spectrometer was used. It has been established that in the observed spectrum a number of low frequency lines are present caused by vibrations of the crystalline lattice. It is shown that the growth of dielectric permittivity near the ferroelectric transition correlates with the observed growth of the spectral intensity in the low frequency spectrum range at the approach to the Gurie temperature. It was found that for the considered crystal, both a ''single-mode'' and a ''two-mode'' behaviour of the phonon spectrum take place

  5. Biostatnet workshop on Biomedical (Big) Data & DoReMi LD-RadStats: Workshop for statisticians interested in contributing to EU low dose radiation research

    CERN Document Server

    Calle, MLuz; Cardis, Elisabeth; Einbeck, Jochen; Gómez, Guadalupe; Puig, Pere

    2017-01-01

    This two-part volume gathers extended conference abstracts corresponding to selected talks from the "Biostatnet workshop on Biomedical (Big) Data" and from the "DoReMi LD-RadStats: Workshop for statisticians interested in contributing to EU low dose radiation research", which were held at the Centre de Recerca Matemàtica (CRM) in Barcelona from November 26th to 27th, 2015, and at the Institut de Salut Global ISGlobal (former CREAL) from October 26th to 28th, 2015, respectively. Most of the contributions are brief articles, presenting preliminary new results not yet published in regular research journals. The first part is devoted to the challenges of analyzing so called "Biomedical Big Data", tremendous amounts of biomedical and health data that are generated every day due to the use of recent technological advances such as massive genomic sequencing, electronic health records or high-resolution medical imaging, among others. The analysis of this information poses significant challenges for researchers in th...

  6. RadCon: A Radiological Consequences Model

    International Nuclear Information System (INIS)

    Crawford, J.; Domel, R.U.

    2000-05-01

    RadCon estimates the dose received by user selected groups in the population from an accidental release of radionuclides to the environment. The exposure pathways considered are external exposure from the cloud and ground and internal exposure from inhalation and ingestion of contaminated food. Atmospheric dispersion modelling is carried out externally to RadCon.Given a two dimensional time varying air and ground concentration of radioactive elements, RadCon allows the user to: view the air and ground concentration over the affected area, select optional parameters and calculate the dose to people,display the results to the user, and change the parameter values. RadCon offers two user interfaces: 1) the standard graphical user interface which is started using Java DoseApp at the command line, or by setting up a shortcut to this command (particularly when RadCon is installed on a PC) and 2) the text based interface used to generate information for the model inter-comparison exercise . This is initiated using Java BIOMASS at the command line, or an equivalent shortcut. The text based interface was developed for research purposes and is not generally available. Appendices A, B and C provide a summary of instructions on setting up RadCon. This will generally be carried out by the computer support personnel

  7. Influence of structural disorder on the optical and transport properties of Co0.50 Ti0.50 alloy films

    International Nuclear Information System (INIS)

    Kim, Ki Won; Lee, Y. P.; Rhee, Joo Yull; Kudryavtsev, Yuriy V.; Ri, H. C.

    2000-01-01

    Co 0.50 Ti 0.50 alloy films with a total thickness of about 100 nm were prepared by flash evaporation of the crushed alloy powders onto heated (730 K for the ordered state) and LN 2 -cooled (150 K for the disordered state) substrates. Structural analysis of the films was performed by suing transmission electron microscopy. The optical conductivity (OC) of the samples was measured at room temperature in a spectral range of 265 -2500 nm (4.7 - 0.5 eV). The resistivity measurements were carried out by using the four-probe technique in a temperature range of 4.2 - 300 K. The experimental OC spectra for the Co 0.50 Ti 0.50 alloys show the most significant change in the infrared region upon the order-disorder transformation. The structural disorder in the Co 0.50 Ti 0.50 alloy film leads to a change in the sign of the temperature coefficient of the resistivity from positive to negative. The observed changes in the optical properties and the temperature dependences of resistivity caused by the order-disorder structural transition are analyzed in the framework of the lattice symmetry and the electronic structure of the ordered CoTi compound

  8. RadWorks Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The RadWorks project's overarching objective is the maturation and demonstration of affordable, enabling solutions to the radiation-related challenges presented to...

  9. Reach Address Database (RAD)

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Reach Address Database (RAD) stores the reach address of each Water Program feature that has been linked to the underlying surface water features (streams,...

  10. RAD9, RAD17; RAD24, and RAD53 control one pathway of resistance to γ irradiation in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Koltovaya, N.A.; Nikulushkina, Yu.V.; Roshina, M.P.; Devin, A.B.

    2009-01-01

    Mechanisms for the genetic control of the cell cycle transition (checkpoint control) have been studied in more detail in yeast Saccharomyces cerevisiae. To clarify tho role of the RAD9, RAD17, RAD24, and RAD53 checkpoint genes in cell radioresistance, diploid double mutants were analyzed for cell sensitivity to ionizing radiation. All mutations in combination with rad9Δ were shown to manifest the epistatic type of interaction. Our results suggest that the RAD9, RAD17, RAD24, and RAD53 checkpoint genes belong to a single epistasis group called the RAD9 group and participate in the same pathway. RAD9 and RAD53 have a positive effect on sensitivity to γ irradiation, whereas RAD17 and RAD24 have a negative effect. For haploid interactions between mutations may differ in the case of γ or UV irradiation, mutations - for example, rad9Δ and rad24Δ - were shown to have an additive effect in the first case and epistatic - in the second. The analyzed genes can also participate in minor mechanisms of radioresistance that are relatively independent of the above major mechanism

  11. RadNuc: a graphical user interface to deliver dose rate patterns encountered in nuclear medicine with a 137Cs irradiator.

    Science.gov (United States)

    Pasternack, Jordan B; Howell, Roger W

    2013-02-01

    The temporal variations in absorbed dose rates to organs and tissues in the body are very large in diagnostic and therapeutic nuclear medicine. The response of biological endpoints of relevance to radiation safety and therapeutic efficacy is generally modulated by dose rate. Therefore, it is important to understand how the complex dose rate patterns encountered in nuclear medicine impact relevant biological responses. Accordingly, a graphical user interface (GUI) was created to control a cesium-137 irradiator to deliver such dose rate patterns. Visual Basic 6.0 was used to create a user-friendly GUI to control the dose rate by varying the thickness of a mercury attenuator. The GUI facilitates the delivery of a number of dose rate patterns including constant, exponential increase or decrease, and multi-component exponential. Extensive visual feedback is provided by the GUI during both the planning and delivery stages. The GUI controlled irradiator can achieve a maximum dose rate of 40 cGy/h and a minimum dose rate of 0.01 cGy/h. Addition of machined lead blocks can be used to further reduce the minimum dose rate to 0.0001 cGy/h. Measured dose rate patterns differed from programmed dose rate patterns in total dose by 3.2% to 8.4%. The GUI controlled irradiator is able to accurately create dose rate patterns encountered in nuclear medicine and other related fields. This makes it an invaluable tool for studying the effects of chronic constant and variable low dose rates on biological tissues in the contexts of both radiation protection and clinical administration of internal radionuclides. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. Interactions of checkpoint-genes RAD9, RAD17, RAD24 and RAD53 determining radioresistance of Yeast Saccharomyces Cerevisiae

    International Nuclear Information System (INIS)

    Koltovaya, N.A.; Nikulushkina, Yu.V.; Roshchina, M.P.; Devin, A.B.

    2007-01-01

    The mechanisms of genetic control of progress through the division cell cycle (checkpoint-control) in yeast Saccharomyces cerevisiae have been studied intensively. To investigate the role of checkpoint-genes RAD9, RAD17, RAD24, RAD53 in cell radioresistance we have investigated cell sensitivity of double mutants to γ-ray. Double mutants involving various combinations with rad9Δ show epistatic interactions, i.e. the sensitivity of the double mutants to γ-ray was no greater than that of more sensitive of the two single mutants. This suggests that all these genes govern the same pathway. This group of genes was named RAD9-epistasis group. It is interesting to note that the genes RAD9 and RAD53 have positive effect but RAD17 and RAD24 have negative effect on radiosensitivity of yeast cells. Interactions between mutations may differ depending on the agent γ-ray or UV-light, for example mutations rad9Δ and rad24Δ show additive effect for γ-ray and epistatic effect for UV-light

  13. Laser-Assisted Synthesis of Mn0.50Zn0.50Fe2O4 Nanomaterial: Characterization and In Vitro Inhibition Activity towards Bacillus subtilis Biofilm

    Directory of Open Access Journals (Sweden)

    Shaukat Ali Shahid

    2015-01-01

    Full Text Available There is growing interest in the development of novel nanomaterials with potential antimicrobial activity and lesser toxicity. In the current research work, Mn0.5Zn0.5Fe2O4 nanoparticles were synthesized via a novel coprecipitation cum laser ablation technique yielding fine spinal structured material. The synthesized nanomaterial was structurally characterized by X-ray diffraction technique which confirmed the formation and the crystalline nature of Mn0.50Zn0.50Fe2O4 nanomaterial. The crystallite size determined by Debye-Scherrer’s formula was found to be ~12 nm. The formation of nanoparticles was evidenced by scanning electron microscopy. Energy dispersive X-ray analysis (EDXA was performed for elemental analysis. The synthesized nanomaterial was interestingly found to be an effective antimicrobial agent and inhibited the growth of Bacillus subtilis biofilm formation. The 5 µg of Mn0.5Zn0.5Fe2O4 nanomaterial dissolved in 1 mL of DMSO showed excellent biofilm inhibitory activity 91.23% ± 1.87 against Bacillus subtilis.

  14. RadGenomics project

    Energy Technology Data Exchange (ETDEWEB)

    Iwakawa, Mayumi; Imai, Takashi; Harada, Yoshinobu [National Inst. of Radiological Sciences, Chiba (Japan). Frontier Research Center] [and others

    2002-06-01

    Human health is determined by a complex interplay of factors, predominantly between genetic susceptibility, environmental conditions and aging. The ultimate aim of the RadGenomics (Radiation Genomics) project is to understand the implications of heterogeneity in responses to ionizing radiation arising from genetic variation between individuals in the human population. The rapid progression of the human genome sequencing and the recent development of new technologies in molecular genetics are providing us with new opportunities to understand the genetic basis of individual differences in susceptibility to natural and/or artificial environmental factors, including radiation exposure. The RadGenomics project will inevitably lead to improved protocols for personalized radiotherapy and reductions in the potential side effects of such treatment. The project will contribute to future research into the molecular mechanisms of radiation sensitivity in humans and will stimulate the development of new high-throughput technologies for a broader application of biological and medical sciences. The staff members are specialists in a variety of fields, including genome science, radiation biology, medical science, molecular biology, and informatics, and have joined the RadGenomics project from various universities, companies, and research institutes. The project started in April 2001. (author)

  15. RadGenomics project

    International Nuclear Information System (INIS)

    Iwakawa, Mayumi; Imai, Takashi; Harada, Yoshinobu

    2002-01-01

    Human health is determined by a complex interplay of factors, predominantly between genetic susceptibility, environmental conditions and aging. The ultimate aim of the RadGenomics (Radiation Genomics) project is to understand the implications of heterogeneity in responses to ionizing radiation arising from genetic variation between individuals in the human population. The rapid progression of the human genome sequencing and the recent development of new technologies in molecular genetics are providing us with new opportunities to understand the genetic basis of individual differences in susceptibility to natural and/or artificial environmental factors, including radiation exposure. The RadGenomics project will inevitably lead to improved protocols for personalized radiotherapy and reductions in the potential side effects of such treatment. The project will contribute to future research into the molecular mechanisms of radiation sensitivity in humans and will stimulate the development of new high-throughput technologies for a broader application of biological and medical sciences. The staff members are specialists in a variety of fields, including genome science, radiation biology, medical science, molecular biology, and informatics, and have joined the RadGenomics project from various universities, companies, and research institutes. The project started in April 2001. (author)

  16. γ radiation dosimetry in Mega rad range using sugar solution

    International Nuclear Information System (INIS)

    Venkataramani, R.; Mehta, S.K.; Soman, S.D.

    1976-01-01

    The formation of malonaldehyde under γ irradiation of solid sucrose and aqueous sucrose, fructose and arabinose solutions has been studied in the Mega rad range. Malonaldehyde (MA) concentration was estimated spectrophotometrically after complexing with 2-thio-barbituric acid. The effect of free radical scavengers (KI and N 2 O) on the yield of MA was investigated. Of the systems studied a 5% aqueous sucrose solution gave a proportional response of MA formation with dose in 0.2 to 5 Mega rad range. A 5% aqueous solution of sucrose prepared from sucrose irradiated in solid state also gave a smooth response of MA yield with dose from 8 to 30 Mega rad. The aqueous and solid sucrose systems together can be conveniently used for dosimetry in the range of 0.2 30 Mega rad. (author)

  17. gamma. radiation dosimetry in Mega rad range using sugar solution

    Energy Technology Data Exchange (ETDEWEB)

    Venkataramani, R; Mehta, S K; Soman, S D [Bhabha Atomic Research Centre, Bombay (India). Health Physics Div.

    1976-09-01

    The formation of malonaldehyde under ..gamma.. irradiation of solid sucrose and aqueous sucrose, fructose and arabinose solutions has been studied in the Mega rad range. Malonaldehyde (MA) concentration was estimated spectrophotometrically after complexing with 2-thio-barbituric acid. The effect of free radical scavengers (KI and N/sub 2/O) on the yield of MA was investigated. Of the systems studied a 5% aqueous sucrose solution gave a proportional response of MA formation with dose in 0.2 to 5 Mega rad range. A 5% aqueous solution of sucrose prepared from sucrose irradiated in solid state also gave a smooth response of MA yield with dose from 8 to 30 Mega rad. The aqueous and solid sucrose systems together can be conveniently used for dosimetry in the range of 0.2 30 Mega rad.

  18. Changes of arterial blood pressure, heart rate, internal body temperature, and blood acido-basic balance in the unanaesthetized rabbit following whole-body gamma irradiation at a mean absorbed dose of 250 rads

    Energy Technology Data Exchange (ETDEWEB)

    Dufour, R.; Court, L.

    1973-09-01

    The general effects of whole-body gamma -irradiation at a mean absorbed dose of 250 rads were studied simultaneously in the unanaesthetized rabbit for 48 hours. They occurred early, with the following characteristics: arterial blood pressure decreased steadily as early as the 2nd hour and reached its minimum value on the 5th hour with a decrease of about 14%; it remained low during the following two days. Heart rate increased during the first hour, was the highest by the end of the second hour, and resumed normal value on the 24th hour. Internal body temperature increased during the 1st hour and was maximum by the end of the 2nd hour, with a mean increase of 1.2 deg C; hyperthermia steadily decreased between the 4th and the 6th hours and had completely disappeared by the 24th hour. Respiratory alkalosis is shown in the acido-basic balance by a raise of pH, a decrease of PCO/sub 2/ and arterial blood bicarbonates. These various changes seem to indicate a double origin, both central and peripheral. (FR)

  19. RADTRAN 6/RadCat 6 user guide.

    Energy Technology Data Exchange (ETDEWEB)

    Weiner, Ruth F.; Hinojosa, Daniel; Heames, Terence John; Farnum, Cathy Ottinger; Kalinina, Elena Arkadievna

    2013-09-01

    This document provides a detailed discussion and a guide for the use of the RadCat 6.0 Graphical User Interface input file generator for the RADTRAN code, Version 6. RadCat 6.0 integrates the newest analysis capabilities of RADTRAN 6.0, including an economic model, updated loss-of-lead shielding model, a new ingestion dose model, and unit conversion. As of this writing, the RADTRAN version in use is RADTRAN 6.02.

  20. Radiation transport simulation of the Martian GCR surface flux and dose estimation using spherical geometry in PHITS compared to MSL-RAD measurements.

    Science.gov (United States)

    Flores-McLaughlin, John

    2017-08-01

    Planetary bodies and spacecraft are predominantly exposed to isotropic radiation environments that are subject to transport and interaction in various material compositions and geometries. Specifically, the Martian surface radiation environment is composed of galactic cosmic radiation, secondary particles produced by their interaction with the Martian atmosphere, albedo particles from the Martian regolith and occasional solar particle events. Despite this complex physical environment with potentially significant locational and geometric dependencies, computational resources often limit radiation environment calculations to a one-dimensional or slab geometry specification. To better account for Martian geometry, spherical volumes with respective Martian material densities are adopted in this model. This physical description is modeled with the PHITS radiation transport code and compared to a portion of measurements from the Radiation Assessment Detector of the Mars Science Laboratory. Particle spectra measured between 15 November 2015 and 15 January 2016 and PHITS model results calculated for this time period are compared. Results indicate good agreement between simulated dose rates, proton, neutron and gamma spectra. This work was originally presented at the 1st Mars Space Radiation Modeling Workshop held in 2016 in Boulder, CO. Copyright © 2017. Published by Elsevier Ltd.

  1. Identification of cloned genes that complement the rad50-1, rad51-1, rad54-3 and rad55-3 mutations in yeast

    International Nuclear Information System (INIS)

    Calderon, I.L.; Contopoulou, C.R.; Mortimer, R.K.

    1982-01-01

    Plasmids that complement the rad50-1, rad51-1, rad54-3 and rad55-3 mutations in yeast, have been isolated. They were obtained by transforming strains, carrying the leu2-112 leu2-3 alleles and the particular rad mutation, with YEp13 plasmids containing near random yeast DNA inserts. Rad + clones were identified among the Leu + transformants. Integration by targeting into the RAD55 locus showed that the rad55-3 complementing plasmid contained the actual RAD55 gene. BamHI fragments from each of the plasmids that complement rad50-1, rad51-1 and rad54-3, all of which lacked Rad + activity, were subcloned into the integrating plasmid YIp5 and the hybrid plasmids were used to transform a Rad + Ura - strain to Ura + . By genetic mapping, the rad51 and rad54 subclones were shown to integrate at their respective loci. However, the rad50 subclones integrated at a site unlinked to the RAD50 locus. This suggests that no homology exists between this BamHI fragment and the RAD50 gene. Integration at the RAD54 locus of the rad54 subclone made the host cell Ura + but Rad - ; excision of the plasmid was shown to be x-ray inducible and to restore the Ura - Rad + phenotype. These results indicate that the BamHI fragment of the RAD54 plasmid is internal to the RAD54 gene. We can conclude also that the RAD54 gene is not essential as cells bearing a disrupted copy of this gene are able to survive. Additionally, a plasmid carrying an amber suppressor has been isolated and characterized

  2. Lymphoid irradiation in intractable rheumatoid arthritis. A double-blind, randomized study comparing 750-rad treatment with 2,000-rad treatment

    International Nuclear Information System (INIS)

    Hanly, J.G.; Hassan, J.; Moriarty, M.; Barry, C.; Molony, J.; Casey, E.; Whelan, A.; Feighery, C.; Bresnihan, B.

    1986-01-01

    Twenty patients with intractable rheumatoid arthritis were treated with 750-rad or 2,000-rad lymphoid irradiation in a randomized double-blind comparative study. Over a 12-month followup period, there was a significant improvement in 4 of 7 and 6 of 7 standard parameters of disease activity following treatment with 750 rads and 2,000 rads, respectively. Transient, short-term toxicity was less frequent with the lower dose. In both groups, there was a sustained peripheral blood lymphopenia, a selective depletion of T helper (Leu-3a+) lymphocytes, and reduced in vitro mitogen responses. These changes did not occur, however, in synovial fluid. These results suggest that 750-rad lymphoid irradiation is as effective as, but less toxic than, that with 2,000 rads in the management of patients with intractable rheumatoid arthritis

  3. Ionizing radiation-induced foci formation of mammalian Rad51 and Rad54 depends on the Rad51 paralogs, but not on Rad52

    International Nuclear Information System (INIS)

    Veelen, Lieneke R. van; Essers, Jeroen; Rakt, Mandy W.M.M. van de; Odijk, Hanny; Pastink, Albert; Zdzienicka, MaIgorzata Z.; Paulusma, Coen C.; Kanaar, Roland

    2005-01-01

    Homologous recombination is of major importance for the prevention of genomic instability during chromosome duplication and repair of DNA damage, especially double-strand breaks. Biochemical experiments have revealed that during the process of homologous recombination the RAD52 group proteins, including Rad51, Rad52 and Rad54, are involved in an essential step: formation of a joint molecule between the broken DNA and the intact repair template. Accessory proteins for this reaction include the Rad51 paralogs and BRCA2. The significance of homologous recombination for the cell is underscored by the evolutionary conservation of the Rad51, Rad52 and Rad54 proteins from yeast to humans. Upon treatment of cells with ionizing radiation, the RAD52 group proteins accumulate at the sites of DNA damage into so-called foci. For the yeast Saccharomyces cerevisiae, foci formation of Rad51 and Rad54 is abrogated in the absence of Rad52, while Rad51 foci formation does occur in the absence of the Rad51 paralog Rad55. By contrast, we show here that in mammalian cells, Rad52 is not required for foci formation of Rad51 and Rad54. Furthermore, radiation-induced foci formation of Rad51 and Rad54 is impaired in all Rad51 paralog and BRCA2 mutant cell lines tested, while Rad52 foci formation is not influenced by a mutation in any of these recombination proteins. Despite their evolutionary conservation and biochemical similarities, S. cerevisiae and mammalian Rad52 appear to differentially contribute to the DNA-damage response

  4. The RadAssessor manual

    Energy Technology Data Exchange (ETDEWEB)

    Seitz, Sharon L.

    2007-02-01

    THIS manual will describe the functions and capabilities that are available from the RadAssessor database and will demonstrate how to retrieve and view its information. You’ll learn how to start the database application, how to log in, how to use the common commands, and how to use the online help if you have a question or need extra guidance. RadAssessor can be viewed from any standard web browser. Therefore, you will not need to install any special software before using RadAssessor.

  5. Dose-dependency of radiation on enzyme production in Trichoderma reesei

    International Nuclear Information System (INIS)

    Kumakura, Minoru

    1993-01-01

    Effect of irradiation dose on the production of cellulase and amylase related enzymes in Trichoderma reesei was studied in which post-irradiation time response pattern was measured. The damage of the cells irradiated with certain irradiation doses (1.40±0.20x10 5 , 2.20±0.10x10 5 , 3.00±0.50x10 5 and 3.50±0.20x10 5 rad) was rapidly recovered. The increased enzyme production in the culture of the irradiated cells resulted from the recovery of radiation damage after irradiation. The function of cell growth was not affected by irradiation below dose of 5x10 5 rad, though the function of enzyme synthesis was drastically affected. (orig.)

  6. Packaging Effects on RadFET Sensors for High Energy Physics Experiments

    CERN Document Server

    Mekki, J; Glaser, M; Guatelli, S; Moll, M; Pia, M G; Ravotti, F

    2009-01-01

    RadFETs in customized chip carrier packages are installed in the LHC Experiments as radiation monitors. The package influence on the dose measurement in the complex LHC radiation environment is evaluated using Geant4 simulations and experimental data.

  7. Defective thymine dimer excision in radiation-sensitive mutants rad10 and rad16 of Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Prakash, L [Rochester Univ., N.Y. (USA). School of Medicine and Dentistry

    1977-04-01

    Two rad mutants of yeast, rad10 and rad16, are shown to be defective in the removal of UV-induced pyrimidine dimers since DNAs obtained from irradiated cells following a post-irradiation incubation in the dark still retain UV-endonuclease-sensitive sites. Both rad10 and rad16 mutants are in the same pathway of excision-repair as the rad1, rad2, rad3, and rad4 mutants.

  8. Long Term RadNet Quality Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — This RadNet Quality Data Asset includes all data since initiation and when ERAMS was expanded to become RadNet, name changed to reflect new mission. This includes...

  9. Preferential binding of yeast Rad4-Rad23 complex to damaged DNA

    International Nuclear Information System (INIS)

    Jansen, L.E.T.; Verhage, R.A.; Brouwer, J.

    1998-01-01

    The yeast Rad4 and Rad23 proteins form a complex that is involved in nucleotide excision repair (NER). Their function in this process is not known yet, but genetic data suggest that they act in an early step in NER. We have purified an epitope-tagged Rad4.Rad23 (tRad4. Rad23) complex from yeast cells, using a clone overproducing Rad4 with a hemagglutinin-tag at its C terminus. tRad4.Rad23 complex purified by both conventional and immuno-affinity chromatography complements the in vitro repair defect of rad4 and rad23 mutant extracts, demonstrating that these proteins are functional in NER. Using electrophoretic mobility shift assays, we show preferential binding of the tRad4.Rad23 complex to damaged DNA in vitro. UV-irradiated, as well as N-acetoxy-2-(acetylamino)fluorene-treated DNA, is efficiently bound by the protein complex. These data suggest that Rad4.Rad23 interacts with DNA damage during NER and may play a role in recognition of the damage

  10. Rad and Mubad in Shahnameh of Ferdowsi

    Directory of Open Access Journals (Sweden)

    z Delpazir

    2011-09-01

    However, the important points overlooked by explicators are the relationship between Rad and Mubad (Zoroastrian priest and the reason why these two words have co-occurred so frequently in Shahnameh, the most famous Persian national epic. It seems that Rad in Shahnameh, based on Avesta and Pahlavi texts, is often construed as Sadane or Dastoor that was a high position in ancient Iran’s religious hierarchy. Thus, Rads and Mubads were both considered members of religious communities. This study tries to investigate the role and position of Rads and Mubads and their relationship with one another, based on Shahnameh of Ferdowsi, in three chapters: The etymology of Rad Rad in Shahnameh The relationship between Rads and Mubads.

  11. Food Irradiation Is Done in Grays, not Rads

    International Nuclear Information System (INIS)

    Strom, Daniel J.

    2002-01-01

    One federal agency has chosen to use exclusively modern SI units of radiation dose in its regulations: the FDA. While not exactly hot news, this bold move by a U.S. government agency on November 26, 1997, should be noted by those who wish to encourage the switch from curies, working level months, rads, rems, and roentgens to becquerels, joule hours per cubic meter, grays, sieverts, and coulombs per kilogram. The regulation is 21 CFR 179, Irradiation in the Production, Processing, and Handling of Food. Specifically, 21 CFR 179.26 (b) 8. permits meat irradiation up to 4.5 kGy for refrigerated meat and 7.0 kGy for frozen meat. Prior to the 1997 addition, radiation doses had been quoted in grays (kGy) with rad (Mrad) values in parentheses. In the 1997 addition, the Mrads disappeared

  12. Overexpression of Rad in muscle worsens diet-induced insulin resistance and glucose intolerance and lowers plasma triglyceride level

    Science.gov (United States)

    Ilany, Jacob; Bilan, Philip J.; Kapur, Sonia; Caldwell, James S.; Patti, Mary-Elizabeth; Marette, Andre; Kahn, C. Ronald

    2006-03-01

    Rad is a low molecular weight GTPase that is overexpressed in skeletal muscle of some patients with type 2 diabetes mellitus and/or obesity. Overexpression of Rad in adipocytes and muscle cells in culture results in diminished insulin-stimulated glucose uptake. To further elucidate the potential role of Rad in vivo, we have generated transgenic (tg) mice that overexpress Rad in muscle using the muscle creatine kinase (MCK) promoter-enhancer. Rad tg mice have a 6- to 12-fold increase in Rad expression in muscle as compared to wild-type littermates. Rad tg mice grow normally and have normal glucose tolerance and insulin sensitivity, but have reduced plasma triglyceride levels. On a high-fat diet, Rad tg mice develop more severe glucose intolerance than the wild-type mice; this is due to increased insulin resistance in muscle, as exemplified by a rightward shift in the dose-response curve for insulin stimulated 2-deoxyglucose uptake. There is also a unexpected further reduction of the plasma triglyceride levels that is associated with increased levels of lipoprotein lipase in the Rad tg mice. These results demonstrate a potential synergistic interaction between increased expression of Rad and high-fat diet in creation of insulin resistance and altered lipid metabolism present in type 2 diabetes. diabetes mellitus | glucose transport | RGK GTPase | transgenic mouse

  13. Roles for the yeast RAD18 and RAD52 DNA repair genes in UV mutagenesis.

    Science.gov (United States)

    Armstrong, J D; Chadee, D N; Kunz, B A

    1994-11-01

    Experimental evidence indicates that although the Saccharomyces cerevisiae RAD18 and RAD52 genes are not required for nucleotide excision repair, they function in the processing of UV-induced DNA damage in yeast. Conflicting statements regarding the UV mutability of strains deleted for RAD18 prompted us to re-examine the influence of RAD18, and RAD52, on UV mutagenesis. To do so, we characterized mutations induced by UV in SUP4-o, a yeast suppressor tRNA gene. SUP4-o was maintained on a plasmid in isogenic strains that either carried one of two different rad18 deletions (rad18 delta) or had RAD52 disrupted. Both rad18 deletions decreased the frequency of UV-induced SUP4-o mutations to levels close to those for spontaneous mutagenesis in the rad18 delta backgrounds, and prevented a net increase in mutant yield. A detailed analysis of mutations isolated after UV irradiation of one of the rad18 delta strains uncovered little evidence of the specificity features typical for UV mutagenesis in the isogenic repair-proficient (RAD) parent (e.g., predominance of G.C-->A.T transitions). Evidently, UV induction of SUP4-o mutations is highly dependent on the RAD18 gene. Compared to the RAD strain, disruption of RAD52 reduced the frequency and yield of UV mutagenesis by about two-thirds. Closer inspection revealed that 80% of this reduction was due to a decrease in the frequency of G.C-->A.T transitions. In addition, there were differences in the distributions and site specificities of single base-pair substitutions. Thus, RAD52 also participates in UV mutagenesis of a plasmid-borne gene in yeast, but to a lesser extent than RAD18.

  14. Neutron powder diffraction investigation on the crystal and magnetic structure of (Ho{sub 0.50+x}Ca{sub 0.50-x})(Mn{sub 1-x}Cr{sub x})O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Martinelli, A; Ferretti, M [SPIN-CNR, Corso Perrone 24, 16152 Genova (Italy); Castellano, C [Dipartimento di Chimica Strutturale e Stereochimica Inorganica, Universita degli Studi di Milano, Via C Venezian 21, 20133 Milano (Italy); Cimberle, M R; Masini, R [IMEM-CNR, Via Dodecaneso 33, 16146 Genova (Italy); Ritter, C, E-mail: alberto.martinelli@spin.cnr.it [Institute Laue-Langevin, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9 (France)

    2011-10-19

    The crystal and magnetic structure of (Ho{sub 0.50+x}Ca{sub 0.50-x})(Mn{sub 1-x}Cr{sub x})O{sub 3} (x = 0.00, 0.01, 0.02, 0.03) has been investigated between 5 and 300 K by means of neutron powder diffraction followed by Rietveld refinement and dc magnetic measurements. During cooling an orthorhombic to monoclinic phase transition occurs on account of the charge and orbital ordering taking place in the Mn sub-lattice; at low temperature phase separation takes place and the main monoclinic phase coexists with a secondary orthorhombic phase, whose amount slightly increases with the increase of Cr content. Cr{sup 3+} is not involved in orbital ordering or superexchange interactions. The charge and magnetic ordering are decoupled: the Mn moments order according to a CE-type structure in all samples. (paper)

  15. Dielectric and impedance studies of Ba0.50(Na0.25Bi0.25)(Fe0.25Nb0.25)Ti0.50O3 ceramic

    Science.gov (United States)

    Yadav, Anjana; Chandra, K. P.; Kulkarni, A. R.; Prasad, K.

    2018-05-01

    Lead-free perovskite Ba0.50(Na0.25Bi0.25)(Fe0.25Nb0.25)Ti0.50O3 was prepared using conventional ceramic technique at 1130°C/4h in air atmosphere and characterized by X-ray diffraction, scanning electron microscopy, dielectric and impedance studies. XRD analysis of the compound indicated the formation of a single-phase cubic structure. SEM study was carried out to study the quality and purity of the compound. Compound showed very high dielectric constant (33700). Impedance analysis indicated the negative temperature coefficient of resistance character of the compound. Ac conductivity data followed Jonscher's law and correlated barrier hopping successfully explained the charge carrier transport mechanism in the system.

  16. Repair of pyrimidine dimers in radiation-sensitive mutants rad3, rad4, rad6, and rad9 of Saccharomyces cerevisiae. [nicking

    Energy Technology Data Exchange (ETDEWEB)

    Prakash, L [Rochester Univ., N.Y. (USA). Dept. of Radiation Biology and Biophysics; Rochester Univ., N.Y. (USA). School of Medicine and Dentistry)

    1977-10-01

    The ability to remove ultraviolet-induced pyrimidine dimers was examined in four radiation-sensitive mutants of Saccharomyces cerevisiae. The susceptibility of DNA from irradiated cells to nicking by either the T4 uv-endonuclease or an endonuclease activity found in crude extracts of Micrococcus luteus was used to measure the presence of dimers in DNA. The rad3 and rad4 mutants are shown to be defective in dimer excision whereas the rad6 and rad9 mutants are proficient in dimer excision.

  17. Function of Rad51 paralogs in eukaryotic homologous recombinational repair

    International Nuclear Information System (INIS)

    Liu, N.; Skowronek, K.

    2003-01-01

    Full text: Homologous recombinational repair (HRR) is an important mechanism for maintaining genetic integrity and cancer prevention by accurately repair of DNA double strand breaks induced by environmental insults or occurred in DNA replication. A critical step in HRR is the polymerization of Rad51 on single stranded DNA to form nuclear protein filaments, the later conduct DNA strand paring and exchange between homologous strands. A number of proteins, including replication protein A (RPA), Rad52 and Rad51 paralogs, are suggested to modulate or facilitate the process of Rad51 filament formation. Five Rad51 paralogs, namely XRCC2, XRCC3, Rad51B, Rad51C and Rad51D have been identified in eucaryotic cells. These proteins show distant protein sequence identity to Rad51, to yeast Rad51 paralogs (Rad55 and Rad57) and to each other. Hamster or chicken mutants of Rad51 paralogs exhibit hypersensitivity to a variety of DNA damaging agents, especially cross-linking agents, and are defective in assembly of Rad51 onto HRR site after DNA damage. Recent data from our and other labs showed that Rad51 paralogs constitute two distinct complexes in cell extracts, one contains XRCC2, Rad51B, Rad51C and Rad51D, and the other contains Rad51C and XRCC3. Rad51C is involved in both complexes. Our results also showed that XRCC3-Rad51C complex interacts with Rad51 in vivo. Furthermore, overexpression of Rad52 can partially suppress the hypersensitivity of XRCC2 mutant irs1 to ionizing radiation and corrected the defects in Rad51 focus formation. These results suggest that XRCC2 and other Rad51 paralogs play a mediator function to Rad51 in the early stage of HRR

  18. Synthesis, structure, and physicochemical investigations of the new α Cu 0.50TiO(PO 4) oxyphosphate

    Science.gov (United States)

    Benmokhtar, S.; Belmal, H.; El Jazouli, A.; Chaminade, J. P.; Gravereau, P.; Pechev, S.; Grenier, J. C.; Villeneuve, G.; de Waal, D.

    2007-02-01

    The room-temperature crystal structure of a new Cu(II) oxyphosphate— α Cu 0.50IITiO(PO 4)—was determined from X-ray single crystals diffraction data, in the monoclinic system, space group P2 1/c. The refinement from 5561 independent reflections lead to the following parameters: a=7.5612(4)Å, b=7.0919(4)Å, c=7.4874(4)Å, β=122.25(1)°, Z=4, with the final R=0.0198, wR=0.0510. The structure of α Cu 0.50IITiO(PO 4) can be described as a TiOPO 4 framework constituted by chains of tilted corner-sharing [TiO 6] octahedra running parallel to the c-axis and cross linked by phosphate [PO 4] tetrahedra, where one-half of octahedral cavities created are occupied by Cu atoms. Ti atoms are displaced from the center of octahedra units in alternating long (2.308 Å) and short (1.722 Å) Ti-O(1) bonds along chains. Such O(1) atoms not linked to P atoms justify the oxyphosphate formulation α Cu 0.50TiO(PO 4). The divalent cations Cu 2+ occupy a Jahn-Teller distorted octahedron sharing two faces with two [TiO 6] octahedra. EPR and optical measurements are in good agreement with structural data. The X-ray diffraction results are supported by Raman and infrared spectroscopy studies that confirmed the existence of the infinite chains -Ti-O-Ti-O-Ti-. α Cu 0.50TiO(PO 4) shows a Curie-Weiss paramagnetic behavior in the temperature range 4-80 K.

  19. RAD51 Is a Selective DNA Repair Target to Radiosensitize Glioma Stem Cells.

    Science.gov (United States)

    King, Harry O; Brend, Tim; Payne, Helen L; Wright, Alexander; Ward, Thomas A; Patel, Karan; Egnuni, Teklu; Stead, Lucy F; Patel, Anjana; Wurdak, Heiko; Short, Susan C

    2017-01-10

    Patients with glioblastoma die from local relapse despite surgery and high-dose radiotherapy. Resistance to radiotherapy is thought to be due to efficient DNA double-strand break (DSB) repair in stem-like cells able to survive DNA damage and repopulate the tumor. We used clinical samples and patient-derived glioblastoma stem cells (GSCs) to confirm that the DSB repair protein RAD51 is highly expressed in GSCs, which are reliant on RAD51-dependent DSB repair after radiation. RAD51 expression and RAD51 foci numbers fall when these cells move toward astrocytic differentiation. In GSCs, the small-molecule RAD51 inhibitors RI-1 and B02 prevent RAD51 focus formation, reduce DNA DSB repair, and cause significant radiosensitization. We further demonstrate that treatment with these agents combined with radiation promotes loss of stem cells defined by SOX2 expression. This indicates that RAD51-dependent repair represents an effective and specific target in GSCs. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  20. Physical mapping and cloning of RAD56

    DEFF Research Database (Denmark)

    Mathiasen, David P; Gallina, Irene; Germann, Susanne Manuela

    2013-01-01

    Here we report the physical mapping of the rad56-1 mutation to the NAT3 gene, which encodes the catalytic subunit of the NatB N-terminal acetyltransferase in Saccharomyces cerevisiae. Mutation of RAD56 causes sensitivity to X-rays, methyl methanesulfonate, zeocin, camptothecin and hydroxyurea...

  1. Randomized comparison of operator radiation exposure comparing transradial and transfemoral approach for percutaneous coronary procedures: rationale and design of the minimizing adverse haemorrhagic events by TRansradial access site and systemic implementation of angioX – RAdiation Dose study (RAD-MATRIX)

    International Nuclear Information System (INIS)

    Sciahbasi, Alessandro; Calabrò, Paolo; Sarandrea, Alessandro; Rigattieri, Stefano; Tomassini, Francesco; Sardella, Gennaro; Zavalloni, Dennis; Cortese, Bernardo; Limbruno, Ugo; Tebaldi, Matteo; Gagnor, Andrea; Rubartelli, Paolo; Zingarelli, Antonio; Valgimigli, Marco

    2014-01-01

    Background: Radiation absorbed by interventional cardiologists is a frequently under-evaluated important issue. Aim is to compare radiation dose absorbed by interventional cardiologists during percutaneous coronary procedures for acute coronary syndromes comparing transradial and transfemoral access. Methods: The randomized multicentre MATRIX (Minimizing Adverse Haemorrhagic Events by TRansradial Access Site and Systemic Implementation of angioX) trial has been designed to compare the clinical outcome of patients with acute coronary syndromes treated invasively according to the access site (transfemoral vs. transradial) and to the anticoagulant therapy (bivalirudin vs. heparin). Selected experienced interventional cardiologists involved in this study have been equipped with dedicated thermoluminescent dosimeters to evaluate the radiation dose absorbed during transfemoral or right transradial or left transradial access. For each access we evaluate the radiation dose absorbed at wrist, at thorax and at eye level. Consequently the operator is equipped with three sets (transfemoral, right transradial or left transradial access) of three different dosimeters (wrist, thorax and eye dosimeter). Primary end-point of the study is the procedural radiation dose absorbed by operators at thorax. An important secondary end-point is the procedural radiation dose absorbed by operators comparing the right or left radial approach. Patient randomization is performed according to the MATRIX protocol for the femoral or radial approach. A further randomization for the radial approach is performed to compare right and left transradial access. Conclusions: The RAD-MATRIX study will probably consent to clarify the radiation issue for interventional cardiologist comparing transradial and transfemoral access in the setting of acute coronary syndromes

  2. Randomized comparison of operator radiation exposure comparing transradial and transfemoral approach for percutaneous coronary procedures: rationale and design of the minimizing adverse haemorrhagic events by TRansradial access site and systemic implementation of angioX – RAdiation Dose study (RAD-MATRIX)

    Energy Technology Data Exchange (ETDEWEB)

    Sciahbasi, Alessandro, E-mail: alessandro.sciahbasi@fastwebnet.it [Interventional Cardiology, Sandro Pertini Hospital – ASL RMB, Rome (Italy); Calabrò, Paolo [Division of Cardiology - Department of Cardio-Thoracic Sciences - Second University of Naples (Italy); Sarandrea, Alessandro [HSE Management, Rome (Italy); Rigattieri, Stefano [Interventional Cardiology, Sandro Pertini Hospital – ASL RMB, Rome (Italy); Tomassini, Francesco [Department of Cardiology, Infermi Hospital, Rivoli (Italy); Sardella, Gennaro [La Sapienza University, Rome (Italy); Zavalloni, Dennis [UO Emodinamica e Cardiologia Invasiva, IRCCS, Istituto Clinico Humanitas, Rozzano (Italy); Cortese, Bernardo [Interventional Cardiology, Fatebenefratelli Hospital, Milan (Italy); Limbruno, Ugo [Cardiology Unit, Misericordia Hospital, Grosseto (Italy); Tebaldi, Matteo [Cardiology Department, University of Ferrara, Department of Cardiology (Italy); Gagnor, Andrea [Department of Cardiology, Infermi Hospital, Rivoli (Italy); Rubartelli, Paolo [Villa Scassi Hospital, Genova (Italy); Zingarelli, Antonio [San Martino Hospital, Genova (Italy); Valgimigli, Marco [Thoraxcenter, Rotterdam (Netherlands)

    2014-06-15

    Background: Radiation absorbed by interventional cardiologists is a frequently under-evaluated important issue. Aim is to compare radiation dose absorbed by interventional cardiologists during percutaneous coronary procedures for acute coronary syndromes comparing transradial and transfemoral access. Methods: The randomized multicentre MATRIX (Minimizing Adverse Haemorrhagic Events by TRansradial Access Site and Systemic Implementation of angioX) trial has been designed to compare the clinical outcome of patients with acute coronary syndromes treated invasively according to the access site (transfemoral vs. transradial) and to the anticoagulant therapy (bivalirudin vs. heparin). Selected experienced interventional cardiologists involved in this study have been equipped with dedicated thermoluminescent dosimeters to evaluate the radiation dose absorbed during transfemoral or right transradial or left transradial access. For each access we evaluate the radiation dose absorbed at wrist, at thorax and at eye level. Consequently the operator is equipped with three sets (transfemoral, right transradial or left transradial access) of three different dosimeters (wrist, thorax and eye dosimeter). Primary end-point of the study is the procedural radiation dose absorbed by operators at thorax. An important secondary end-point is the procedural radiation dose absorbed by operators comparing the right or left radial approach. Patient randomization is performed according to the MATRIX protocol for the femoral or radial approach. A further randomization for the radial approach is performed to compare right and left transradial access. Conclusions: The RAD-MATRIX study will probably consent to clarify the radiation issue for interventional cardiologist comparing transradial and transfemoral access in the setting of acute coronary syndromes.

  3. Randomized comparison of operator radiation exposure comparing transradial and transfemoral approach for percutaneous coronary procedures: rationale and design of the minimizing adverse haemorrhagic events by TRansradial access site and systemic implementation of angioX - RAdiation Dose study (RAD-MATRIX).

    Science.gov (United States)

    Sciahbasi, Alessandro; Calabrò, Paolo; Sarandrea, Alessandro; Rigattieri, Stefano; Tomassini, Francesco; Sardella, Gennaro; Zavalloni, Dennis; Cortese, Bernardo; Limbruno, Ugo; Tebaldi, Matteo; Gagnor, Andrea; Rubartelli, Paolo; Zingarelli, Antonio; Valgimigli, Marco

    2014-06-01

    Radiation absorbed by interventional cardiologists is a frequently under-evaluated important issue. Aim is to compare radiation dose absorbed by interventional cardiologists during percutaneous coronary procedures for acute coronary syndromes comparing transradial and transfemoral access. The randomized multicentre MATRIX (Minimizing Adverse Haemorrhagic Events by TRansradial Access Site and Systemic Implementation of angioX) trial has been designed to compare the clinical outcome of patients with acute coronary syndromes treated invasively according to the access site (transfemoral vs. transradial) and to the anticoagulant therapy (bivalirudin vs. heparin). Selected experienced interventional cardiologists involved in this study have been equipped with dedicated thermoluminescent dosimeters to evaluate the radiation dose absorbed during transfemoral or right transradial or left transradial access. For each access we evaluate the radiation dose absorbed at wrist, at thorax and at eye level. Consequently the operator is equipped with three sets (transfemoral, right transradial or left transradial access) of three different dosimeters (wrist, thorax and eye dosimeter). Primary end-point of the study is the procedural radiation dose absorbed by operators at thorax. An important secondary end-point is the procedural radiation dose absorbed by operators comparing the right or left radial approach. Patient randomization is performed according to the MATRIX protocol for the femoral or radial approach. A further randomization for the radial approach is performed to compare right and left transradial access. The RAD-MATRIX study will probably consent to clarify the radiation issue for interventional cardiologist comparing transradial and transfemoral access in the setting of acute coronary syndromes. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. RAD51AP2, a novel vertebrate- and meiotic-specific protein, sharesa conserved RAD51-interacting C-terminal domain with RAD51AP1/PIR51

    Energy Technology Data Exchange (ETDEWEB)

    Kovalenko, Oleg V.; Wiese, Claudia; Schild, David

    2006-07-25

    Many interacting proteins regulate and/or assist the activities of RAD51, a recombinase which plays a critical role in both DNA repair and meiotic recombination. Yeast two-hybrid screening of a human testis cDNA library revealed a new protein, RAD51AP2 (RAD51 Associated Protein 2), that interacts strongly with RAD51. A full-length cDNA clone predicts a novel vertebrate specific protein of 1159 residues, and the RAD51AP2 transcript was observed only in meiotic tissue (i.e. adult testis and fetal ovary), suggesting a meiotic-specific function for RAD51AP2. In HEK293 cells the interaction of RAD51 with an ectopically-expressed recombinant large fragment of RAD51AP2 requires the C-terminal 57 residues of RAD51AP2. This RAD51-binding region shows 81% homology to the C-terminus of RAD51AP1/PIR51, an otherwise totally unrelated RAD51-binding partner that is ubiquitously expressed. Analyses using truncations and point mutations in both RAD51AP1 and RAD51AP2 demonstrate that these proteins use the same structural motif for RAD51 binding. RAD54 shares some homology with this RAD51-binding motif, but this homologous region plays only an accessory role to the adjacent main RAD51-interacting region, which has been narrowed here to 40 amino acids. A novel protein, RAD51AP2, has been discovered that interacts with RAD51 through a C-terminal motif also present in RAD51AP1.

  5. Protective effect of the LevRad on treat of paracoccidioidomycosis

    International Nuclear Information System (INIS)

    Martins, Estefania M.N.; Andrade, Antero S.R.; Fernandes, Viviane Cristina; Morais, Elis Araujo; Goes, Alfredo M.; Resende, Maria Aparecida de

    2011-01-01

    Paracoccidioides brasiliensis is the agent of Paracoccidioidomycosis (PCM), the most prevalent deep mycosis of Latin America. The period of treat depend on the chemotherapeutic and the severity of disease and its administration not ensure the complete destruction of the fungus. The search for new alternatives is necessary. The aim of this study was to evaluate the protective effect of yeast cells of P. brasiliensis attenuated by gamma irradiation (LevRad) on therapeutic vaccination of BALB/c. The therapeutic potential of LevRad with or without fluconazole was assessed for the first time, intraperitoneally, in BALB/c, 60 days after intratracheal infection with a highly virulent non-irradiated P.brasiliensis isolate. The animals were divided in five experimental groups: uninfected (C-), infected (C+), infected treated with fluconazole (Inmed), infected treated with LevRad (InRad) and infected treated with fluconazole + LevRad (InRadMed). The organs (lungs, spleen and liver) were collected to analyze CFU (colony forming units) and histology. The sera were used to evaluate the immunization efficacy, and to assess IgG subtypes (IgG1, IgG2a, IgG2b, IgG3) and total IgG levels. There was significant decrease in the CFU counts of the lungs of InMed, InRadMed and InRad. No were visualized histopathological alterations in the organs of these groups, except in InRad there was granulomatous lesions unifocal, little and discrete. The levels of IgG and its subtypes IgG2a, IgG2b increased, probably due to the increase of cytokines that promote switching to these isotypes. These preliminary results can provide new prospect for immunotherapy of PCM, but it will be necessary new studies to evaluate administration dose and period treatment. (author)

  6. Lead free dielectric ceramic with stable relative permittivity of 0.90(Na0.50Bi0.50Ti)O3-0.10AgNbO3

    Science.gov (United States)

    Verma, Anita; Yadav, Arun Kumar; Kumar, Sunil; Sen, Somaditya

    2018-04-01

    Structural, dielectric and ferroelectric properties in perovskite 0.90(Na0.50Bi0.50Ti)03-0.10AgNb03 polycrystalline powders prepared by sol-gel method are discussed. Diffuse phase transition and new type of dielectric anomaly was observed with highly steady capacitive properties in the 135-450 °C temperature range. This compound shows remarkable dielectric with dielectric constant ɛr 1000 with a variation of ± 7% and tan δ = 0.004 0.25 in 135- 450 °C temperature. In addition, it also showed excellent ferroelectric properties with saturation polarization Ps = 13.5 μC/cm2, remnant polarization of Pr = 7.6 μC/cm2 and a low coercive field Ec = 36 kV/cm at room temperature. Stable dielectric constant (ɛr) and low dielectric loss (tan δ) in a wide temperature range observed for the titled composition makes it an interesting candidate for potential use in fast growing "high-temperature electronics" industry applications.

  7. Nanoscale Ferroelectric Switchable Polarization and Leakage Current Behavior in (Ba0.50Sr0.50(Ti0.80Sn0.20O3 Thin Films Prepared Using Chemical Solution Deposition

    Directory of Open Access Journals (Sweden)

    Venkata Sreenivas Puli

    2015-01-01

    Full Text Available Nanoscale switchable ferroelectric (Ba0.50Sr0.50(Ti0.80Sn0.20O3-BSTS polycrystalline thin films with a perovskite structure were prepared on Pt/TiOx/SiO2/Si substrate by chemical solution deposition. X-ray diffraction (XRD spectra indicate that a cubic perovskite crystalline structure and Raman spectra revealed that a tetragonal perovskite crystalline structure is present in the thin films. Sr2+ and Sn4+ cosubstituted film exhibited the lowest leakage current density. Piezoresponse Force Microscopy (PFM technique has been employed to acquire out-of-plane (OPP piezoresponse images and local piezoelectric hysteresis loop in polycrystalline BSTS films. PFM phase and amplitude images reveal nanoscale ferroelectric switching behavior at room temperature. Square patterns with dark and bright contrasts were written by local poling and reversible nature of the piezoresponse behavior was established. Local piezoelectric butterfly amplitude and phase hysteresis loops display ferroelectric nature at nanoscale level. The significance of this paper is to present ferroelectric/piezoelectric nature in present BSTS films at nanoscale level and corroborating ferroelectric behavior by utilizing Raman spectroscopy. Thus, further optimizing physical and electrical properties, BSTS films might be useful for practical applications which include nonvolatile ferroelectric memories, data-storage media, piezoelectric actuators, and electric energy storage capacitors.

  8. Synergistic interactions between RAD5, RAD16, and RAD54, three partially homologous yeast DNA repair genes each in a different repair pathway

    International Nuclear Information System (INIS)

    Glassner, B.J.; Mortimer, R.K.

    1994-01-01

    Considerable homology has recently been noted between the proteins encoded by the RAD5, RAD16 and RAD54 genes of Saccharomyces cerevisiae. These genes are members of the RAD6, RAD3 and RAD50 epistasis groups, respectively, which correspond to the three major DNA repair pathways in yeast. These proteins also share homology with other eucaryotic proteins, including those encoded by SNF2 and MO1 of yeast, brahma and lodestar of Drosophila and the human ERCC6 gene. The homology shares features with known helicases, suggesting a newly identified helicase subfamily. We have constructed a series of congenic single-, double- and triple-deletion mutants involving RAD5, RAD16 and RAD54 to examine the interactions between these genes. Each deletion mutation alone has only a moderate effect on survival after exposure to UV radiation. Each pairwise-double mutant exhibits marked synergism. The triple-deletion mutant displays further synergism. These results confirm the assignment of the RAD54 gene to the RAD50 epistasis group and suggest that the RAD16 gene plays a larger role in DNA repair after exposure to UV radiation than has been suggested previously. Additionally, the proteins encoded by RAD5, RAD16, and RAD54 may compete for the same substrate after damage induced by UV radiation, possibly at an early step in their respective pathways. 49 refs., 6 figs., 2 tabs

  9. NARAC Dispersion Model Product Integration With RadResponder

    Energy Technology Data Exchange (ETDEWEB)

    Aluzzi, Fernando [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-09-30

    Work on enhanced cooperation and interoperability of Nuclear Incident Response Teams (NIRT) is a joint effort between DHS/FEMA, DOE/NNSA and EPA. One such effort was the integration between the RadResponder Network, a resource sponsored by FEMA for the management of radiological data during an emergency, and the National Atmospheric Advisory Center (NARAC), a DOE/NNSA modeling resource whose predictions are used to aid radiological emergency preparedness and response. Working together under a FEMA-sponsored project these two radiological response assets developed a capability to read and display plume model prediction results from the NARAC computer system in the RadResponder software tool. As a result of this effort, RadResponder users have been provided with NARAC modeling predictions of contamination areas, radiological dose levels, and protective action areas (e.g., areas warranting worker protection or sheltering/evacuation) to help guide protective action decisions and field monitoring surveys, and gain key situation awareness following a radiological/nuclear accident or incident (e.g., nuclear power plant accident, radiological dispersal device incident, or improvised nuclear detonation incident). This document describes the details of this integration effort.

  10. Thickness dependent structural, magnetic and magneto-transport properties of epitaxial Nd{sub 0.50}Sr{sub 0.50}MnO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Pawan, E-mail: p.kumar@krmangalam.edu.in [School of Basic and Applied Sciences, K. R. Mangalam University, Sohna Road, Gurgaon, Haryana 122103 (India); Singh, Hari Krishna, E-mail: hks65@nplindia.org [CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India)

    2016-05-06

    We report the thickness-dependent structural, magnetic and magneto-transport properties in epitaxial Nd{sub 0.50}Sr{sub 0.50}MnO{sub 3} thin films (10 to 300nm) prepared by DC magnetron sputtering technique on single crystalline (001) oriented substrate LaAlO{sub 3}. X-ray diffraction pattern reveals the epitaxial growth of all the films and the out-of-plane lattice parameter of films were found to increase with thickness. As thickness of the film increases the paramagnetic insulator (PMI) to ferromagnetic metal (FMM) transition temperature (T{sub C}), charge ordered transition temperature (T{sub CO}) and magnetic moment were found to increase with a strong bifurcation in ZFC-FC magnetization. The asymmetry in the coercivity seen in field dependent magnetization loops (M-H loops) suggests the presence of exchange bias (EB) effect. While temperature dependent resistivity of films show the semiconducting nature for thickness 10-200nm in temperature range from 5-300K, the film of thickness 300nm shows the insulator to metal transition with transition temperature (T{sub IM}) at 175K. Temperature dependent low field magnetoresistance (LFMR) measured at 4kOe found to decrease with thickness and for high field magnetoresistance (HFMR) at 40kOe and 60kOe also show similar dependence and a crossover at intermediate temperature range in the magnitude of MR between 10nm and 200nm films at constant field. Colossal increase in magnetoresistance observed for 10nm film at low temperature.

  11. RAD51B in Familial Breast Cancer

    OpenAIRE

    Pelttari, L.M.; Khan, S.; et al.,

    2016-01-01

    Common variation on 14q24.1, close to RAD51B, has been associated with breast cancer: rs999737\\ud and rs2588809 with the risk of female breast cancer and rs1314913 with the risk of male breast\\ud cancer. The aim of this study was to investigate the role of RAD51B variants in breast cancer\\ud predisposition, particularly in the context of familial breast cancer in Finland. We sequenced the\\ud coding region of RAD51B in 168 Finnish breast cancer patients from the Helsinki region for\\ud identifi...

  12. RAD51B in familial breast cancer

    OpenAIRE

    Pelttari, LM; Khan, S; Vuorela, M; Kiiski, JI; Vilske, S; Nevanlinna, V; Ranta, S; Schleutker, J; Winqvist, R; Kallioniemi, A; Dörk, T; Bogdanova, NV; Figueroa, J; Pharoah, PDP; Schmidt, MK

    2016-01-01

    Common variation on 14q24.1, close to RAD51B, has been associated with breast cancer: rs999737 and rs2588809 with the risk of female breast cancer and rs1314913 with the risk of male breast cancer. The aim of this study was to investigate the role of RAD51B variants in breast cancer predisposition, particularly in the context of familial breast cancer in Finland. We sequenced the coding region of RAD51B in 168 Finnish breast cancer patients from the Helsinki region for identification of possi...

  13. Kinetics of growing the disordered antiphase domains in titanium carbohydride TiC0.50H0.21

    International Nuclear Information System (INIS)

    Khidirov, I.; Sotvoldiev, D.I.

    2010-01-01

    For establishing formation and growth laws of the disordered nanostructures (the antiphase domains) in the nonstoichiometric titanium carbohydride with cubic NaCl type structure we quenched the titanium carbohydride TiC 0.50 H 0.21 from 1000 deg C followed by annealing at 500, 600, 700, 800 deg C with 24 hour ageing. Neutron diffraction patterns were recorded after each annealing temperature. The half-width of the superstructure (111) reflection is shown to decrease with increasing the annealing temperature that testified on the disordered nanostructure size growing with temperature. The sizes of the disordered nanostructure formed at various temperatures and their dependence D = f(T) were determined on the basis of the neutron diffraction data. (authors)

  14. RadNet Air Quality (Deployable) Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — RadNet Deployable Monitoring is designed to collect radiological and meteorological information and data asset needed to establish the impact of radiation levels on...

  15. Performance in a 12-hour, 300-rad profile

    International Nuclear Information System (INIS)

    Yochmowitz, M.G.; Brown, G.C.

    1977-01-01

    A discrete behavioral task was initiated to study the effects of a 300-rad variable dose rate exposure profile upon positively (food reward) and negatively (mild shock) reinforced groups of primates. Animals performed the task for 12 h. Performance decrements were readily apparent in 2 of 8 shock and 2 of 7 food animals, while delayed reaction times were found in 3 of 8 shock and 3 of 7 food animals. Of the 7 food animals, 4 exhibited emesis, while 1 of 8 shock animals vomited. Such information is useful to military planners who need guidelines to indicate potential aircrew nuclear vulnerability and survivability

  16. RadConEd: A Graphical Data Editor for the Radiological Consequences Model, RadCon

    International Nuclear Information System (INIS)

    Crawford, J.; Domel, R.U.

    2000-05-01

    This document describes the application, RadConEd, which has been designed and implemented to enable users of the RadCon system to update these parameter files. The RadCon system is written in the Java programming language, and as such provides portability across computer platforms. The software described in this report was developed in line with the portability requirements of RadCon, thus providing a uniform user interface across computer platforms and bypassing the need of using system editors. In addition a number of data integrity measures were implemented

  17. A Statistical Analysis of Laser Ablated Ba(Sub 0.50)Sr(Sub 0.50)TiO(Sub 3)/LaAlO(Sub 3) Films for Microwave Applications

    Science.gov (United States)

    Romanofsky, R. R.; Varaljay, N. C.; Alterovitz, S. A.; Miranda, F. A.; Mueller, C. M.; VanKeuls, F. W.; Kim, J.; Harshavardhan, K. S.

    2002-01-01

    The NASA Glenn Research Center is constructing a 616 element scanning phased array antenna using thin film Ba(sub x)Sr(sub 1-x)TiO(sub 3) based phase shifters. A critical milestone is the production of 616 identical phase shifters at 19 GHz with [asymptotically equal to]4 dB insertion loss and at least 337.5 deg phase shift with 3 percent bandwidth. It is well known that there is a direct relationship between dielectric tuning and loss due to the Kramers-Kronig relationship and that film crystallinity and strain, affected by the substrate template, play an important role. Ba(sub 0.50)Sr(sub 0.50)TiO (sub 3) films, nominally 400 nm thick, were deposited on 48 0.25 mm thick, 5 cm diameter LaAlO(sub 3) wafers. Although previous results suggested that Mn-doped films on MgO were intrinsically superior in terms of phase shift per unit loss, for this application phase shift per unit length was more important. The composition was selected as a compromise between tuning and loss for room temperature operation (e.g. crystallinity progressively degrades for Ba concentrations in excess of 30 percent). As a prelude to fabricating the array, it was necessary to process, screen, and inventory a large number of samples. Variable angle ellipsometry was used to characterize refractive index and film thickness across each wafer. Microstructural properties of the thin films were characterized using high resolution X-ray diffractometry. Finally, prototype phase shifters and resonators were patterned on each wafer and RE probed to measure tuning as a function of dc bias voltage as well as peak (0 field) permittivity and unloaded Q. The relationship among film quality and uniformity and performance is analyzed. This work presents the first statistically relevant study of film quality and microwave performance and represents a milestone towards commercialization of thin ferroelectric films for microwave applications.

  18. Tissue dose in thorotrast patients

    International Nuclear Information System (INIS)

    Kaul, A.; Noffz, W.

    1978-01-01

    Absorbed doses to the liver, spleen, red marrow, lungs, kidneys, and to various parts of bone tissue were calculated for long-term burdens of intravascularly injected Thorotrast. The estimates were performed for typical injection levels of 10, 30, 50 and 100 ml, based upon best estimates of 232 Th tissue distribution, and steady state activity ratios between the subsequent daughters. Correcting for the α-particle self absorption within Thorotrast aggregates, the mean α-dose to a standard 70-kg man at 30 yr after the injection 0f 25 ml of Thorotrast is 750 rad to the liver, 2100 rad to the spleen, 270 rad to the red marrow, 60-620 rad in various parts of the lung, and 13 rad to the kidneys. Dose rates to various parts of bone tissue (bone surface, compact, and cancellous bone) were estimated by applying the ICRP model on alkaline earth metabolism to the continuous translocation of thorium daughters to bone and to the formation of thorium daughters by decay within bone tissue. The average dose to calcified bone from translocated 224 Ra with its daughters is 18 rad at 30 yr after the injection of 25 ml of Thorotrast. Considering the Spiess-Mays risk coefficient of 0.9-1.7% bone sarcoma/ 100 rad of average skeletal dose from 224 Ra and its daughters, the induction of 1.6-3.1 bone sarcomas per 1000 Thorotrast patients is predicted. (author)

  19. Schizosaccharomyces pombe Rad22A and Rad22B have similar biochemical properties and form multimeric structures

    Energy Technology Data Exchange (ETDEWEB)

    Vries, Femke A.T. de [Department of Toxicogenetics, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden (Netherlands); Zonneveld, Jose B.M. [Department of Toxicogenetics, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden (Netherlands); Groot, Anton J. de [Department of Toxicogenetics, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden (Netherlands); Koning, Roman I. [Department of Molecular Cell Biology, Leiden University Medical Center, Leiden (Netherlands); Zeeland, Albert A. van [Department of Toxicogenetics, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden (Netherlands); Pastink, Albert [Department of Toxicogenetics, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden (Netherlands)]. E-mail: A.Pastink@lumc.nl

    2007-02-03

    The Saccharomyces cerevisiae Rad52 protein has a crucial role in the repair of DNA double-strand breaks by homologous recombination. In vitro, Rad52 displays DNA binding and strand annealing activities and promotes Rad51-mediated strand exchange. Schizosaccharomyces pombe has two Rad52 homologues, Rad22A and Rad22B. Whereas rad22A deficient strains exhibit severe defects in repair and recombination, rad22B mutants have a much less severe phenotype. To better understand the role of Rad22A and Rad22B in double-strand break repair, both proteins were purified to near homogeneity. Using gel retardation and filter binding assays, binding of Rad22A and Rad22B to short single-stranded DNAs was demonstrated. Binding of Rad22A to double-stranded oligonucleotides or linearized plasmid molecules containing blunt ends or short single-stranded overhangs could not be detected. Rad22B also does not bind efficiently to short duplex oligonucleotides but binds readily to DNA fragments containing 3'-overhangs. Rad22A as well as Rad22B efficiently promote annealing of complementary single-stranded DNAs. In the presence of Rad22A annealing of complementary DNAs is almost 90%. Whereas in reactions containing Rad22B the maximum level of annealing is 60%, most likely due to inhibition of the reaction by duplex DNA. Gel-filtration experiments and electron microscopic analyses indicate self-association of Rad22A and Rad22B and the formation of multimeric structures as has been observed for Rad52 in yeast and man.

  20. High dose radiotherapy for pituitary tumours

    International Nuclear Information System (INIS)

    Mead, K.W.

    1981-01-01

    The results of treatment of 120 pituitary tumours are presented. Based on this experience operable chromophobe adenomas are now treated with 5,000 rads in 4 weeks and inoperable ones receive an additional central dose to 7,500 rads. Pituitary Cushing's tumours are given 10,000 rads in 5 weeks using small fields and acromegalics 5,000 rads to the whole sella and 7,500 to its lower half. The absence of complications at these dose levels is attributed to the use of small fields and the precise application of treatment

  1. High dose radiotherapy for pituitary tumours

    Energy Technology Data Exchange (ETDEWEB)

    Mead, K.W. (Queensland Radium Inst., Herston (Australia))

    1981-11-01

    The results of treatment of 120 pituitary tumours are presented. Based on this experience operable chromophobe adenomas are now treated with 5,000 rads in 4 weeks and inoperable ones receive an additional central dose to 7,500 rads. Pituitary Cushing's tumours are given 10,000 rads in 5 weeks using small fields and acromegalics 5,000 rads to the whole sella and 7,500 to its lower half. The absence of complications at these dose levels is attributed to the use of small fields and the precise application of treatment.

  2. Conservatism in SRS Criticality Alarm System 12 Rad Zone Calculations - How Much is Enough?

    International Nuclear Information System (INIS)

    Yates, K.R.

    2002-01-01

    Savannah River Site (SRS) uses two methods (i.e., Approximate Method and MCNP) of calculating the 12-rad zone. The reasons for the two-tier approach are described in Ref. 1 and 2. Lately, there have been occasions in which the use of either the Approximate Method (AM) or MCNP3 calculations indicated potential facility impacts. For example, one or both methods may indicate that a 12-rad zone extends outside of relatively thick shielding, or extends to the roof of a facility, or extends through shielding to part of a stairwell. In such cases, a criticality alarm system may have to be installed to protect workers in a small, localized area from a potential dose that is not substantially greater than 12 rad in air. But, is the potential dose really greater than 12 rad in air? A subcommittee was appointed to look into the two 12-rad zone calculation methods for the purpose of identifying items contributing to over-conservatism and under-conservatism, and to recommend a path forward

  3. The gene dosage effect of the rad52 mutation on X-ray survival curves of tetraploid yeast strains

    International Nuclear Information System (INIS)

    Ho, K.S.Y.

    1975-01-01

    The mutation rad52 in the yeast Saccharomyces cerevisiae confers sensitivity to X-rays. The gene dosage effect of this mutation on X-ray survival curves of tetraploid yeast strains is shown. With increasing number of rad52 alleles, both a decrease in the survival for a given dose and a decrease in the survival curve shoulder width are observed. The generation of such a family of survival curves using three different mathematical models is discussed

  4. Dependence of total dose response of bipolar linear microcircuits on applied dose rate

    International Nuclear Information System (INIS)

    McClure, S.; Will, W.; Perry, G.; Pease, R.L.

    1994-01-01

    The effect of dose rate on the total dose radiation hardness of three commercial bipolar linear microcircuits is investigated. Total dose tests of linear bipolar microcircuits show larger degradation at 0.167 rad/s than at 90 rad/s even after the high dose rate test is followed by a room temperature plus a 100 C anneal. No systematic correlation could be found for degradation at low dose rate versus high dose rate and anneal. Comparison of the low dose rate with the high dose rate anneal data indicates that MIL-STD-883, method 1019.4 is not a worst-case test method when applied to bipolar microcircuits for low dose rate space applications

  5. Evaluation of COTS Rad Detection Apps

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Eric [National Security Technologies, LLC. (NSTec), Mercury, NV (United States)

    2014-02-01

    Mobile applications are currently under distribution to smart phones utilizing the built-in charge coupled-device (CCD) camera as a radiation detector. The CCD detector has a very low but measurable gamma interaction cross section so the mechanism is feasible, especially for higher dose rate environments. Given that in a large release of radioactive material these ‘crowd sourced’ measurements will be put forth for consideration, a testing and evaluation of the accuracy and uncertainty of the Apps is a critical endeavor. Not only is the accuracy of the reported measurement of concern to the immediate user’s safety, a quantitative uncertainty is required for a government response such as the Federal Radiological Monitoring and Assessment Center (FRMAC) to accept the values for consideration in the determination of regions exceeding protective action guidelines. Already, prompted by the Fukushima nuclear material releases, several repositories of this crowd-sourced data have been created (http://japan.failedrobot.com, http://www.stubbytour.com/nuc/index_en.asp, and http://www.rdtn.org) although the question remains as to the reliability of measurements incorporated into these repositories. In cases of conflict between the real-time published crowd-sourced data and governmental protective actions prepared literature should be on-hand documenting why the difference, if any, exists. Four applications for iOS devices were obtained along with hardware to benchmark their performance. Gamma/X-Ray Detector by Stephan Hotto, Geiger Camera by Senscare, and RadioactivityCounter App by Hotray LTD are all the applications available for distribution within the US that utilize the CCD camera sensor for detection of radiation levels. The CellRad app under development by Idaho National Laboratory for the Android platform was evaluated. In addition, iRad Geiger with the associated hardware accessory was also benchmarked. Radiation fields were generated in a Cs-137 JL Shepherd

  6. Evaluation of COTS Rad Detection Apps

    International Nuclear Information System (INIS)

    Wagner, Eric

    2014-01-01

    Mobile applications are currently under distribution to smart phones utilizing the built-in charge coupled-device (CCD) camera as a radiation detector. The CCD detector has a very low but measurable gamma interaction cross section so the mechanism is feasible, especially for higher dose rate environments. Given that in a large release of radioactive material these 'crowd sourced' measurements will be put forth for consideration, a testing and evaluation of the accuracy and uncertainty of the Apps is a critical endeavor. Not only is the accuracy of the reported measurement of concern to the immediate user's safety, a quantitative uncertainty is required for a government response such as the Federal Radiological Monitoring and Assessment Center (FRMAC) to accept the values for consideration in the determination of regions exceeding protective action guidelines. Already, prompted by the Fukushima nuclear material releases, several repositories of this crowd-sourced data have been created (http://japan.failedrobot.com, http://www.stubbytour.com/nuc/index_en.asp, and http://www.rdtn.org) although the question remains as to the reliability of measurements incorporated into these repositories. In cases of conflict between the real-time published crowd-sourced data and governmental protective actions prepared literature should be on-hand documenting why the difference, if any, exists. Four applications for iOS devices were obtained along with hardware to benchmark their performance. Gamma/X-Ray Detector by Stephan Hotto, Geiger Camera by Senscare, and RadioactivityCounter App by Hotray LTD are all the applications available for distribution within the US that utilize the CCD camera sensor for detection of radiation levels. The CellRad app under development by Idaho National Laboratory for the Android platform was evaluated. In addition, iRad Geiger with the associated hardware accessory was also benchmarked. Radiation fields were generated in a Cs-137 JL

  7. Radiological information management system (RadIMS)

    International Nuclear Information System (INIS)

    Oesterling, R.G.; Marko, S.A.; Tschaeche, A.N.

    1991-01-01

    Westinghouse Idaho Nuclear Company, Inc. (WINCO) is developing and implementing an information management system, known as RadIMS, to track and record personnel exposure to ionizing radiation. RadIMS has been designed to fulfill all the requirements of US Department of Energy (USDOE) Order 5480.11, ''Radiation Protection for Occupational Workers.'' This Order requires the contractor to maintain detailed radiation exposure records on all individuals who work at the facility. These records must be retrievable for the entire working life of the individual and be available to other USDOE contractors on request. To meet these general needs, RadIMS provides for retrieval of detailed, comprehensive individual exposure histories as well as the usual online interactions to accomplish day-today radiation protection operations. These two extremes of functionality require different approaches in the WINCO computing environment. The exposure histories include database text, paper, microfilm, and electronic bitmaps

  8. Radiological information management system (RadIMS)

    Energy Technology Data Exchange (ETDEWEB)

    Oesterling, R.G.; Marko, S.A.; Tschaeche, A.N.

    1991-08-19

    Westinghouse Idaho Nuclear Company, Inc. (WINCO) is developing and implementing an information management system, known as RadIMS, to track and record personnel exposure to ionizing radiation. RadIMS has been designed to fulfill all the requirements of US Department of Energy (USDOE) Order 5480.11, Radiation Protection for Occupational Workers.'' This Order requires the contractor to maintain detailed radiation exposure records on all individuals who work at the facility. These records must be retrievable for the entire working life of the individual and be available to other USDOE contractors on request. To meet these general needs, RadIMS provides for retrieval of detailed, comprehensive individual exposure histories as well as the usual online interactions to accomplish day-today radiation protection operations. These two extremes of functionality require different approaches in the WINCO computing environment. The exposure histories include database text, paper, microfilm, and electronic bitmaps.

  9. Radiological information management system (RadIMS)

    Energy Technology Data Exchange (ETDEWEB)

    Oesterling, R.G.; Marko, S.A.; Tschaeche, A.N.

    1991-08-19

    Westinghouse Idaho Nuclear Company, Inc. (WINCO) is developing and implementing an information management system, known as RadIMS, to track and record personnel exposure to ionizing radiation. RadIMS has been designed to fulfill all the requirements of US Department of Energy (USDOE) Order 5480.11, ``Radiation Protection for Occupational Workers.`` This Order requires the contractor to maintain detailed radiation exposure records on all individuals who work at the facility. These records must be retrievable for the entire working life of the individual and be available to other USDOE contractors on request. To meet these general needs, RadIMS provides for retrieval of detailed, comprehensive individual exposure histories as well as the usual online interactions to accomplish day-today radiation protection operations. These two extremes of functionality require different approaches in the WINCO computing environment. The exposure histories include database text, paper, microfilm, and electronic bitmaps.

  10. Effect of 680 rad whole-body irradiation of a human fetus, 27 years afterwards

    International Nuclear Information System (INIS)

    Kallinger, W.; Granninger, W.

    1982-01-01

    In 1953 a 38-year-old pregnant woman was given radiation treatment with Ra-226 due to a vaginal carcinoma. The radiation field was reproduced by means of a computer program. It was proved that the fetus was exposed to radiation doses of 50-2000 rad. Despite this high dose no abnormalities were found during clinical examination of the now 27-year-old man who has already fathered a healthy son. (orig.) [de

  11. The role of Rad 51 protein in radioresistance of spheroid model of Du 145 prostate carcinoma cell line

    International Nuclear Information System (INIS)

    Taghizadeh, M.; Khoei, S.; Nikoofar, A. R.; Ghamsari, L.; Goliaei, B.

    2009-01-01

    Rad 51 is a protein with critical role in double strand break repair. Down-regulation of this protein has a significant effect in radiosensitivity of some cell lines like prostate carcinoma. Compared to monolayer cell culture model, the spheroids are more resistant to radiation. The aim of the current study was to determine the Rad 51 protein level in Du 145 spheroids, and monolayer cells before and after exposure to gamma irradiation. Materials and Methods: In the present study, western blot was used to determine the level of Rad 51 protein in Du 145 cell line grown as monolayer and spheroid. Results: Western blot analysis showed that in the spheroid cells, Rad 51 had an elevated level before and after radiation in comparison with monolayer cells. Higher doses of radiation induced elevated expression of Rad 51 protein in both culture models.The level of at protein after exposure to gamma rays had been time-dependent. Conclusion: Rad 51 might act as a mediator of radiation resistance in tumor cells. Repression of Rad 51 activity could be a prominent strategy to overcome radiation resistance of tumors.

  12. Simulation of the GCR spectrum in the Mars curiosity rover's RAD detector using MCNP6

    Science.gov (United States)

    Ratliff, Hunter N.; Smith, Michael B. R.; Heilbronn, Lawrence

    2017-08-01

    The paper presents results from MCNP6 simulations of galactic cosmic ray (GCR) propagation down through the Martian atmosphere to the surface and comparison with RAD measurements made there. This effort is part of a collaborative modeling workshop for space radiation hosted by Southwest Research Institute (SwRI). All modeling teams were tasked with simulating the galactic cosmic ray (GCR) spectrum through the Martian atmosphere and the Radiation Assessment Detector (RAD) on-board the Curiosity rover. The detector had two separate particle acceptance angles, 4π and 30 ° off zenith. All ions with Z = 1 through Z = 28 were tracked in both scenarios while some additional secondary particles were only tracked in the 4π cases. The MCNP6 4π absorbed dose rate was 307.3 ± 1.3 μGy/day while RAD measured 233 μGy/day. Using the ICRP-60 dose equivalent conversion factors built into MCNP6, the simulated 4π dose equivalent rate was found to be 473.1 ± 2.4 μSv/day while RAD reported 710 μSv/day.

  13. Simulation of the GCR spectrum in the Mars curiosity rover's RAD detector using MCNP6.

    Science.gov (United States)

    Ratliff, Hunter N; Smith, Michael B R; Heilbronn, Lawrence

    2017-08-01

    The paper presents results from MCNP6 simulations of galactic cosmic ray (GCR) propagation down through the Martian atmosphere to the surface and comparison with RAD measurements made there. This effort is part of a collaborative modeling workshop for space radiation hosted by Southwest Research Institute (SwRI). All modeling teams were tasked with simulating the galactic cosmic ray (GCR) spectrum through the Martian atmosphere and the Radiation Assessment Detector (RAD) on-board the Curiosity rover. The detector had two separate particle acceptance angles, 4π and 30 ° off zenith. All ions with Z = 1 through Z = 28 were tracked in both scenarios while some additional secondary particles were only tracked in the 4π cases. The MCNP6 4π absorbed dose rate was 307.3 ± 1.3 µGy/day while RAD measured 233 µGy/day. Using the ICRP-60 dose equivalent conversion factors built into MCNP6, the simulated 4π dose equivalent rate was found to be 473.1 ± 2.4 µSv/day while RAD reported 710 µSv/day. Copyright © 2017 The Committee on Space Research (COSPAR). Published by Elsevier Ltd. All rights reserved.

  14. Rad51-Rad52 mediated maintenance of centromeric chromatin in Candida albicans.

    Directory of Open Access Journals (Sweden)

    Sreyoshi Mitra

    2014-04-01

    Full Text Available Specification of the centromere location in most eukaryotes is not solely dependent on the DNA sequence. However, the non-genetic determinants of centromere identity are not clearly defined. While multiple mechanisms, individually or in concert, may specify centromeres epigenetically, most studies in this area are focused on a universal factor, a centromere-specific histone H3 variant CENP-A, often considered as the epigenetic determinant of centromere identity. In spite of variable timing of its loading at centromeres across species, a replication coupled early S phase deposition of CENP-A is found in most yeast centromeres. Centromeres are the earliest replicating chromosomal regions in a pathogenic budding yeast Candida albicans. Using a 2-dimensional agarose gel electrophoresis assay, we identify replication origins (ORI7-LI and ORI7-RI proximal to an early replicating centromere (CEN7 in C. albicans. We show that the replication forks stall at CEN7 in a kinetochore dependent manner and fork stalling is reduced in the absence of the homologous recombination (HR proteins Rad51 and Rad52. Deletion of ORI7-RI causes a significant reduction in the stalled fork signal and an increased loss rate of the altered chromosome 7. The HR proteins, Rad51 and Rad52, have been shown to play a role in fork restart. Confocal microscopy shows declustered kinetochores in rad51 and rad52 mutants, which are evidence of kinetochore disintegrity. CENP-ACaCse4 levels at centromeres, as determined by chromatin immunoprecipitation (ChIP experiments, are reduced in absence of Rad51/Rad52 resulting in disruption of the kinetochore structure. Moreover, western blot analysis reveals that delocalized CENP-A molecules in HR mutants degrade in a similar fashion as in other kinetochore mutants described before. Finally, co-immunoprecipitation assays indicate that Rad51 and Rad52 physically interact with CENP-ACaCse4 in vivo. Thus, the HR proteins Rad51 and Rad52

  15. RadBall Technology Testing and MCNP Modeling of the Tungsten Collimator.

    Science.gov (United States)

    Farfán, Eduardo B; Foley, Trevor Q; Coleman, J Rusty; Jannik, G Timothy; Holmes, Christopher J; Oldham, Mark; Adamovics, John; Stanley, Steven J

    2010-01-01

    The United Kingdom's National Nuclear Laboratory (NNL) has developed a remote, non-electrical, radiation-mapping device known as RadBall(™), which can locate and quantify radioactive hazards within contaminated areas of the nuclear industry. RadBall(™) consists of a colander-like outer shell that houses a radiation-sensitive polymer sphere. The outer shell works to collimate radiation sources and those areas of the polymer sphere that are exposed react, becoming increasingly more opaque, in proportion to the absorbed dose. The polymer sphere is imaged in an optical-CT scanner, which produces a high resolution 3D map of optical attenuation coefficients. Subsequent analysis of the optical attenuation matrix provides information on the spatial distribution of sources in a given area forming a 3D characterization of the area of interest. RadBall(™) has no power requirements and can be positioned in tight or hard-to reach locations. The RadBall(™) technology has been deployed in a number of technology trials in nuclear waste reprocessing plants at Sellafield in the United Kingdom and facilities of the Savannah River National Laboratory (SRNL). This study focuses on the RadBall(™) testing and modeling accomplished at SRNL.

  16. RadBall™ Technology Testing and MCNP Modeling of the Tungsten Collimator

    Science.gov (United States)

    Farfán, Eduardo B.; Foley, Trevor Q.; Coleman, J. Rusty; Jannik, G. Timothy; Holmes, Christopher J.; Oldham, Mark; Adamovics, John; Stanley, Steven J.

    2010-01-01

    The United Kingdom’s National Nuclear Laboratory (NNL) has developed a remote, non-electrical, radiation-mapping device known as RadBall™, which can locate and quantify radioactive hazards within contaminated areas of the nuclear industry. RadBall™ consists of a colander-like outer shell that houses a radiation-sensitive polymer sphere. The outer shell works to collimate radiation sources and those areas of the polymer sphere that are exposed react, becoming increasingly more opaque, in proportion to the absorbed dose. The polymer sphere is imaged in an optical-CT scanner, which produces a high resolution 3D map of optical attenuation coefficients. Subsequent analysis of the optical attenuation matrix provides information on the spatial distribution of sources in a given area forming a 3D characterization of the area of interest. RadBall™ has no power requirements and can be positioned in tight or hard-to reach locations. The RadBall™ technology has been deployed in a number of technology trials in nuclear waste reprocessing plants at Sellafield in the United Kingdom and facilities of the Savannah River National Laboratory (SRNL). This study focuses on the RadBall™ testing and modeling accomplished at SRNL. PMID:21617740

  17. Mars science laboratory radiation assessment detector (MSL/RAD) modeling workshop proceedings

    Science.gov (United States)

    Hassler, Donald M.; Norbury, John W.; Reitz, Günther

    2017-08-01

    The Radiation Assessment Detector (RAD) (Hassler et al., 2012; Zeitlin et al., 2016) onboard the Mars Science Laboratory (MSL) Curiosity rover (Grotzinger et al., 2012) is a sophisticated charged and neutral particle radiation analyzer developed by an international team of scientists and engineers from Southwest Research Institute in Boulder, Colorado as the leading institution, the University of Kiel and the German Aerospace Center in Cologne, Germany. RAD is a compact, powerful instrument capable of distinguishing between ionizing particles and neutral particles and providing neutron, gamma, and charged particle spectra from protons to iron as well as absorbed dose measurements in tissue-equivalent material. During the 6 month cruise to Mars, inside the MSL spacecraft, RAD served as a proxy to validate models of the radiation levels expected inside a spacecraft that future astronauts might experience (Zeitlin et al., 2013). RAD was turned on one day after the landing on August 7, 2012, exactly 100 years to the day after the discovery of cosmic rays on Earth by Victor Hess. These measurements are the first of their kind on the surface of another planet (Hassler et al., 2014), and the radiation data collected by RAD on the surface of Mars will inform projections of crew health risks and the design of protective surface habitats and other countermeasures for future human missions in the coming decades.

  18. HiRadMat: materials under scrutiny

    CERN Multimedia

    Anaïs Schaeffer

    2011-01-01

    CERN's new facility, HiRadMat (High Radiation to Materials), which is designed to test materials for the world's future particle accelerators, should be operational and welcoming its first experiments by the end of the year.   The HiRadMat facility, located in the TNC tunnel. The materials used in the LHC and its experiments are exposed to very high-energy particles. The LHC machine experts obviously didn't wait for the first collisions in the world's most powerful accelerator to put the materials through their paces - the equipment was validated following a series of stringent tests. And these tests will get even tougher now, with the arrival of HiRadMat. The tunnel that formerly housed the West Area Neutrino Facility (WANF) has been completely revamped to make way for CERN's latest facility, HiRadMat. Supported by the Radioprotection service, a team from the Engineering (EN) Department handled the dismantling operations from October 2009 to December 2010. "We could only work on disman...

  19. RAD51B in Familial Breast Cancer

    DEFF Research Database (Denmark)

    Pelttari, Liisa M; Khan, Sofia; Vuorela, Mikko

    2016-01-01

    Common variation on 14q24.1, close to RAD51B, has been associated with breast cancer: rs999737 and rs2588809 with the risk of female breast cancer and rs1314913 with the risk of male breast cancer. The aim of this study was to investigate the role of RAD51B variants in breast cancer predisposition......, particularly in the context of familial breast cancer in Finland. We sequenced the coding region of RAD51B in 168 Finnish breast cancer patients from the Helsinki region for identification of possible recurrent founder mutations. In addition, we studied the known rs999737, rs2588809, and rs1314913 SNPs and RAD......51B haplotypes in 44,791 breast cancer cases and 43,583 controls from 40 studies participating in the Breast Cancer Association Consortium (BCAC) that were genotyped on a custom chip (iCOGS). We identified one putatively pathogenic missense mutation c.541C>T among the Finnish cancer patients...

  20. RadNet Air Data From Sacramento, CA

    Science.gov (United States)

    This page presents radiation air monitoring and air filter analysis data for Sacramento, CA from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  1. RadNet Air Data From Honolulu, HI

    Science.gov (United States)

    This page presents radiation air monitoring and air filter analysis data for Honolulu, HI from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  2. RadNet Air Quality (Fixed Station) Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — RadNet is a national network of monitoring stations that regularly collect air for analysis of radioactivity. The RadNet network, which has stations in each State,...

  3. RadNet Air Data From Austin, TX

    Science.gov (United States)

    This page presents radiation air monitoring and air filter analysis data for Austin, TX from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  4. RadNet Air Data From Mason City, IA

    Science.gov (United States)

    This page presents radiation air monitoring and air filter analysis data for Mason City, IA from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  5. RadNet Air Data From Little Rock, AR

    Science.gov (United States)

    This page presents radiation air monitoring and air filter analysis data for Little Rock, AR from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  6. RadNet Air Data From Houston, TX

    Science.gov (United States)

    This page presents radiation air monitoring and air filter analysis data for Houston, TX from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  7. RadNet Air Data From Fort Smith, AR

    Science.gov (United States)

    This page presents radiation air monitoring and air filter analysis data for Fort Smith, AR from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  8. RadNet Air Data From Orlando, FL

    Science.gov (United States)

    This page presents radiation air monitoring and air filter analysis data for Orlando, FL from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  9. Promotion of Homologous Recombination and Genomic Stability byRAD51AP1 via RAD51 Recombinase Enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Wiese, Claudia; Dray, Eloise; Groesser, Torsten; San Filippo,Joseph; Shi, Idina; Collins, David W.; Tsai, Miaw-Sheue; Williams,Gareth; Rydberg, Bjorn; Sung, Patrick; Schild, David

    2007-04-11

    Homologous recombination (HR) repairs chromosome damage and is indispensable for tumor suppression in humans. RAD51 mediates the DNA strand pairing step in HR. RAD51AP1 (RAD51 Associated Protein 1) is a RAD51-interacting protein whose function has remained elusive. Knockdown of RAD51AP1 in human cells by RNA interference engenders sensitivity to different types of genotoxic stress. Moreover, RAD51AP1-depleted cells are impaired for the recombinational repair of a DNA double-strand break and exhibit chromatid breaks both spontaneously and upon DNA damaging treatment. Purified RAD51AP1 binds dsDNA and RAD51, and it greatly stimulates the RAD51-mediated D-loop reaction. Biochemical and cytological results show that RAD51AP1 functions at a step subsequent to the assembly of the RAD51-ssDNA nucleoprotein filament. Our findings provide the first evidence that RAD51AP1 helps maintain genomic integrity via RAD51 recombinase enhancement.

  10. RIVER-RAD, Radionuclide Transport in Surface Waters

    International Nuclear Information System (INIS)

    1996-01-01

    1 - Description of program or function: RIVER-RAD assesses the potential fate of radionuclides released to rivers. The model is simplified in nature and is intended to provide guidance in determining the potential importance of the surface water pathway, relevant transport mechanisms, and key radionuclides in estimating radiological dose to man. 2 - Method of solution: A compartmental linear transfer model is used in RIVER-RAD. The river system model in the code is divided into reaches (compartments) of equal size, each with a sediment compartment below it. The movement of radionuclides is represented by a series of transfers between the reaches, and between the water and sediment compartments of each reach. Within each reach (for both the water and sediment compartments), the radionuclides are assumed to be uniformly mixed. Upward volatilization is allowed from the water compartment, and the transfer of radionuclides between the reaches is determined by the flow rate of the river. Settling and resuspension velocities determine the transfer of absorbed radionuclides between the water and sediment compartments. Radioactive decay and decay-product buildup are incorporated into all transport calculations for all radionuclide chains specified by the user. Each nuclide may have unique input and removal rates. Volatilization and radiological decay are considered as linear rate constants in the model. 3 - Restrictions on the complexity of the problem: None noted

  11. Optimized stacked RADFETs for milli-rad dose measurement

    International Nuclear Information System (INIS)

    O'Connell, B.; Lane, B.; Mohammadzadeh, A.

    1999-01-01

    This paper details the improvements in the design of stacked RADFETs for increased radiation sensitivity. The issues of high read-out voltage has been shown to be a draw-back. It is the body (bulk)effect factor that is responsible for the increased overall stack Threshold voltage (V T ), which is greater than the sum of the individual devices V T . From extensive process and device simulation and resultant circuit simulation, modified stack structures have been proposed and designed. New and exciting result of lower initial (pre-irradiation) output voltage as well as increased radiation sensitivity will be presented. (author)

  12. RadNet Radiological Air Monitoring Network

    International Nuclear Information System (INIS)

    Scott Telofski, J.; Askren, D.R.; Petko, Ch.M.; Fraass, R.G.

    2010-01-01

    The United States Environmental Protection Agency operates a national environmental radiation monitoring program called RadNet. RadNet monitors airborne particulates, precipitation, milk, and drinking water for radiation levels. The primary purpose of the original program in the 1950's and 1960's was to collect and analyze samples in various media to assess the effects of radioactive fallout from above-ground nuclear weapon testing. As above-ground testing diminished in the 1970's, the program, especially the air network, became critical in evaluating effects of other types of nuclear incidents, such as the nuclear reactor accident at Chernobyl, as well as monitoring trends in environmental radioactive contamination. The value of rapid data collection subsequent to such incidents led to the consideration of developing air monitors with radiation detectors and telecommunication equipment for real-time radiation measurement. The strengthened United States homeland security posture after 2001 led to production and installation of the current real-time RadNet air monitors. There are now 118 stationary, continuously operating air monitoring stations and 40 mobile air monitors for site specific monitoring. The stationary air monitors include radiation detectors, meteorological sensors, a high-volume air sampler, and communication devices for hourly data transfers. When unusual levels are detected, scientists download a full sodium iodide detector spectrum for analysis. The real-time data collected by RadNet stationary systems permit rapid identification and quantification of airborne nuclides with sufficient sensitivity to provide critical information to help determine protective actions. The data also may help to rapidly refine long-range radioactive plume models and estimate exposure to the population. This paper provides an overview of the airborne particulate monitoring conducted during above-ground nuclear weapon testing, summarizes the uses of data from the program

  13. Updates from the MSL-RAD Experiment on the Mars Curiosity Rover

    Science.gov (United States)

    Zeitlin, Cary

    2015-01-01

    The MSL-RAD instrument continues to operate flawlessly on Mars. As of this writing, some 1040 sols (Martian days) of data have been successfully acquired. Several improvements have been made to the instrument's configuration, particularly aimed at enabling the analysis of neutral-particle data. The dose rate since MSL's landing in August 2012 has remained remarkably stable, reflecting the unusual and very weak solar maximum of Cycle 24. Only a few small SEP events have been observed by RAD, which is shielded by the Martian atmosphere. Gale Crater, where Curiosity landed, is 4.4 km below the mean surface of Mars, and the column depth of atmosphere above is approximately 20 g/sq cm, which provides significant attenuation of GCR heavy ions and SEPs. Recent analysis results will be presented, including updated estimates of the neutron contributions to dose and dose equivalent in cruise and on the surface of Mars.

  14. Coordination of Rad1-Rad10 interactions with Msh2-Msh3, Saw1 and RPA is essential for functional 3' non-homologous tail removal.

    Science.gov (United States)

    Eichmiller, Robin; Medina-Rivera, Melisa; DeSanto, Rachel; Minca, Eugen; Kim, Christopher; Holland, Cory; Seol, Ja-Hwan; Schmit, Megan; Oramus, Diane; Smith, Jessica; Gallardo, Ignacio F; Finkelstein, Ilya J; Lee, Sang Eun; Surtees, Jennifer A

    2018-04-06

    Double strand DNA break repair (DSBR) comprises multiple pathways. A subset of DSBR pathways, including single strand annealing, involve intermediates with 3' non-homologous tails that must be removed to complete repair. In Saccharomyces cerevisiae, Rad1-Rad10 is the structure-specific endonuclease that cleaves the tails in 3' non-homologous tail removal (3' NHTR). Rad1-Rad10 is also an essential component of the nucleotide excision repair (NER) pathway. In both cases, Rad1-Rad10 requires protein partners for recruitment to the relevant DNA intermediate. Msh2-Msh3 and Saw1 recruit Rad1-Rad10 in 3' NHTR; Rad14 recruits Rad1-Rad10 in NER. We created two rad1 separation-of-function alleles, rad1R203A,K205A and rad1R218A; both are defective in 3' NHTR but functional in NER. In vitro, rad1R203A,K205A was impaired at multiple steps in 3' NHTR. The rad1R218A in vivo phenotype resembles that of msh2- or msh3-deleted cells; recruitment of rad1R218A-Rad10 to recombination intermediates is defective. Interactions among rad1R218A-Rad10 and Msh2-Msh3 and Saw1 are altered and rad1R218A-Rad10 interactions with RPA are compromised. We propose a model in which Rad1-Rad10 is recruited and positioned at the recombination intermediate through interactions, between Saw1 and DNA, Rad1-Rad10 and Msh2-Msh3, Saw1 and Msh2-Msh3 and Rad1-Rad10 and RPA. When any of these interactions is altered, 3' NHTR is impaired.

  15. Human RAD18 interacts with ubiquitylated chromatin components and facilitates RAD9 recruitment to DNA double strand breaks.

    Directory of Open Access Journals (Sweden)

    Akiko Inagaki

    Full Text Available RAD18 is an ubiquitin ligase involved in replicative damage bypass and DNA double-strand break (DSB repair processes. We found that RPA is required for the dynamic pattern of RAD18 localization during the cell cycle, and for accumulation of RAD18 at sites of γ-irradiation-induced DNA damage. In addition, RAD18 colocalizes with chromatin-associated conjugated ubiquitin and ubiquitylated H2A throughout the cell cycle and following irradiation. This localization pattern depends on the presence of an intact, ubiquitin-binding Zinc finger domain. Using a biochemical approach, we show that RAD18 directly binds to ubiquitylated H2A and several other unknown ubiquitylated chromatin components. This interaction also depends on the RAD18 Zinc finger, and increases upon the induction of DSBs by γ-irradiation. Intriguingly, RAD18 does not always colocalize with regions that show enhanced H2A ubiquitylation. In human female primary fibroblasts, where one of the two X chromosomes is inactivated to equalize X-chromosomal gene expression between male (XY and female (XX cells, this inactive X is enriched for ubiquitylated H2A, but only rarely accumulates RAD18. This indicates that the binding of RAD18 to ubiquitylated H2A is context-dependent. Regarding the functional relevance of RAD18 localization at DSBs, we found that RAD18 is required for recruitment of RAD9, one of the components of the 9-1-1 checkpoint complex, to these sites. Recruitment of RAD9 requires the functions of the RING and Zinc finger domains of RAD18. Together, our data indicate that association of RAD18 with DSBs through ubiquitylated H2A and other ubiquitylated chromatin components allows recruitment of RAD9, which may function directly in DSB repair, independent of downstream activation of the checkpoint kinases CHK1 and CHK2.

  16. RAD51B in Familial Breast Cancer.

    Directory of Open Access Journals (Sweden)

    Liisa M Pelttari

    Full Text Available Common variation on 14q24.1, close to RAD51B, has been associated with breast cancer: rs999737 and rs2588809 with the risk of female breast cancer and rs1314913 with the risk of male breast cancer. The aim of this study was to investigate the role of RAD51B variants in breast cancer predisposition, particularly in the context of familial breast cancer in Finland. We sequenced the coding region of RAD51B in 168 Finnish breast cancer patients from the Helsinki region for identification of possible recurrent founder mutations. In addition, we studied the known rs999737, rs2588809, and rs1314913 SNPs and RAD51B haplotypes in 44,791 breast cancer cases and 43,583 controls from 40 studies participating in the Breast Cancer Association Consortium (BCAC that were genotyped on a custom chip (iCOGS. We identified one putatively pathogenic missense mutation c.541C>T among the Finnish cancer patients and subsequently genotyped the mutation in additional breast cancer cases (n = 5259 and population controls (n = 3586 from Finland and Belarus. No significant association with breast cancer risk was seen in the meta-analysis of the Finnish datasets or in the large BCAC dataset. The association with previously identified risk variants rs999737, rs2588809, and rs1314913 was replicated among all breast cancer cases and also among familial cases in the BCAC dataset. The most significant association was observed for the haplotype carrying the risk-alleles of all the three SNPs both among all cases (odds ratio (OR: 1.15, 95% confidence interval (CI: 1.11-1.19, P = 8.88 x 10-16 and among familial cases (OR: 1.24, 95% CI: 1.16-1.32, P = 6.19 x 10-11, compared to the haplotype with the respective protective alleles. Our results suggest that loss-of-function mutations in RAD51B are rare, but common variation at the RAD51B region is significantly associated with familial breast cancer risk.

  17. RAD51B in Familial Breast Cancer

    Science.gov (United States)

    Pelttari, Liisa M.; Khan, Sofia; Vuorela, Mikko; Kiiski, Johanna I.; Vilske, Sara; Nevanlinna, Viivi; Ranta, Salla; Schleutker, Johanna; Winqvist, Robert; Kallioniemi, Anne; Dörk, Thilo; Bogdanova, Natalia V.; Figueroa, Jonine; Pharoah, Paul D. P.; Schmidt, Marjanka K.; Dunning, Alison M.; García-Closas, Montserrat; Bolla, Manjeet K.; Dennis, Joe; Michailidou, Kyriaki; Wang, Qin; Hopper, John L.; Southey, Melissa C.; Rosenberg, Efraim H.; Fasching, Peter A.; Beckmann, Matthias W.; Peto, Julian; dos-Santos-Silva, Isabel; Sawyer, Elinor J.; Tomlinson, Ian; Burwinkel, Barbara; Surowy, Harald; Guénel, Pascal; Truong, Thérèse; Bojesen, Stig E.; Nordestgaard, Børge G.; Benitez, Javier; González-Neira, Anna; Neuhausen, Susan L.; Anton-Culver, Hoda; Brenner, Hermann; Arndt, Volker; Meindl, Alfons; Schmutzler, Rita K.; Brauch, Hiltrud; Brüning, Thomas; Lindblom, Annika; Margolin, Sara; Mannermaa, Arto; Hartikainen, Jaana M.; Chenevix-Trench, Georgia; Van Dyck, Laurien; Janssen, Hilde; Chang-Claude, Jenny; Rudolph, Anja; Radice, Paolo; Peterlongo, Paolo; Hallberg, Emily; Olson, Janet E.; Giles, Graham G.; Milne, Roger L.; Haiman, Christopher A.; Schumacher, Fredrick; Simard, Jacques; Dumont, Martine; Kristensen, Vessela; Borresen-Dale, Anne-Lise; Zheng, Wei; Beeghly-Fadiel, Alicia; Grip, Mervi; Andrulis, Irene L.; Glendon, Gord; Devilee, Peter; Seynaeve, Caroline; Hooning, Maartje J.; Collée, Margriet; Cox, Angela; Cross, Simon S.; Shah, Mitul; Luben, Robert N.; Hamann, Ute; Torres, Diana; Jakubowska, Anna; Lubinski, Jan; Couch, Fergus J.; Yannoukakos, Drakoulis; Orr, Nick; Swerdlow, Anthony; Darabi, Hatef; Li, Jingmei; Czene, Kamila; Hall, Per; Easton, Douglas F.; Mattson, Johanna; Blomqvist, Carl; Aittomäki, Kristiina; Nevanlinna, Heli

    2016-01-01

    Common variation on 14q24.1, close to RAD51B, has been associated with breast cancer: rs999737 and rs2588809 with the risk of female breast cancer and rs1314913 with the risk of male breast cancer. The aim of this study was to investigate the role of RAD51B variants in breast cancer predisposition, particularly in the context of familial breast cancer in Finland. We sequenced the coding region of RAD51B in 168 Finnish breast cancer patients from the Helsinki region for identification of possible recurrent founder mutations. In addition, we studied the known rs999737, rs2588809, and rs1314913 SNPs and RAD51B haplotypes in 44,791 breast cancer cases and 43,583 controls from 40 studies participating in the Breast Cancer Association Consortium (BCAC) that were genotyped on a custom chip (iCOGS). We identified one putatively pathogenic missense mutation c.541C>T among the Finnish cancer patients and subsequently genotyped the mutation in additional breast cancer cases (n = 5259) and population controls (n = 3586) from Finland and Belarus. No significant association with breast cancer risk was seen in the meta-analysis of the Finnish datasets or in the large BCAC dataset. The association with previously identified risk variants rs999737, rs2588809, and rs1314913 was replicated among all breast cancer cases and also among familial cases in the BCAC dataset. The most significant association was observed for the haplotype carrying the risk-alleles of all the three SNPs both among all cases (odds ratio (OR): 1.15, 95% confidence interval (CI): 1.11–1.19, P = 8.88 x 10−16) and among familial cases (OR: 1.24, 95% CI: 1.16–1.32, P = 6.19 x 10−11), compared to the haplotype with the respective protective alleles. Our results suggest that loss-of-function mutations in RAD51B are rare, but common variation at the RAD51B region is significantly associated with familial breast cancer risk. PMID:27149063

  18. Conditions needed to give meaning to rad-equivalence principle

    International Nuclear Information System (INIS)

    Latarjet, R.

    1980-01-01

    To legislate on mutagenic chemical pollution the problem to be faced is similar to that tackled about 30 years ago regarding pollution by ionizing radiations. It would be useful to benefit from the work of these 30 years by establishing equivalences, if possible, between chemical mutagens and radiations. Inevitable mutagenic pollutions are considered here, especially those associated with fuel based energy production. As with radiations the legislation must derive from a compromise between the harmful and beneficial effects of the polluting system. When deciding on tolerance doses it is necessary to safeguard the biosphere without inflicting excessive restrictions on industry and on the economy. The present article discusses the conditions needed to give meaning to the notion of rad-equivalence. Some examples of already established equivalences are given, together with the first practical consequences which emerge [fr

  19. PI-RADS v2: Current standing and future outlook.

    Science.gov (United States)

    Smith, Clayton P; Türkbey, Barış

    2018-05-01

    The Prostate Imaging-Reporting and Data System (PI-RADS) was created in 2012 to establish standardization in prostate multiparametric magnetic resonance imaging (mpMRI) acquisition, interpretation, and reporting. In hopes of improving upon some of the PI-RADS v1 shortcomings, the PI-RADS Steering Committee released PI-RADS v2 in 2015. This paper reviews the accuracy, interobserver agreement, and clinical outcomes of PI-RADS v2 and comments on the limitations of the current literature. Overall, PI-RADS v2 shows improved sensitivity and similar specificity compared to PI-RADS v1. However, concerns exist regarding interobserver agreement and the heterogeneity of the study methodology.

  20. Analysis list: RAD21 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ncedbc.jp/kyushu-u/hg19/target/RAD21.1.tsv http://dbarchive.biosciencedbc.jp/kyushu...-u/hg19/target/RAD21.5.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/RAD21.10.tsv http://dbarchive.bioscience...dbc.jp/kyushu-u/hg19/colo/RAD21.Blood.tsv,http://dbarchive.bioscience...dbc.jp/kyushu-u/hg19/colo/RAD21.Breast.tsv,http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/RAD21.Dige...stive_tract.tsv,http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/RAD21.Liver.tsv,http://dbarchive.bioscience

  1. The Martian surface radiation environment – a comparison of models and MSL/RAD measurements

    Directory of Open Access Journals (Sweden)

    Matthiä Daniel

    2016-01-01

    Full Text Available Context: The Radiation Assessment Detector (RAD on the Mars Science Laboratory (MSL has been measuring the radiation environment on the surface of Mars since August 6th 2012. MSL-RAD is the first instrument to provide detailed information about charged and neutral particle spectra and dose rates on the Martian surface, and one of the primary objectives of the RAD investigation is to help improve and validate current radiation transport models. Aims: Applying different numerical transport models with boundary conditions derived from the MSL-RAD environment the goal of this work was to both provide predictions for the particle spectra and the radiation exposure on the Martian surface complementing the RAD sensitive range and, at the same time, validate the results with the experimental data, where applicable. Such validated models can be used to predict dose rates for future manned missions as well as for performing shield optimization studies. Methods: Several particle transport models (GEANT4, PHITS, HZETRN/OLTARIS were used to predict the particle flux and the corresponding radiation environment caused by galactic cosmic radiation on Mars. From the calculated particle spectra the dose rates on the surface are estimated. Results: Calculations of particle spectra and dose rates induced by galactic cosmic radiation on the Martian surface are presented. Although good agreement is found in many cases for the different transport codes, GEANT4, PHITS, and HZETRN/OLTARIS, some models still show large, sometimes order of magnitude discrepancies in certain particle spectra. We have found that RAD data is helping to make better choices of input parameters and physical models. Elements of these validated models can be applied to more detailed studies on how the radiation environment is influenced by solar modulation, Martian atmosphere and soil, and changes due to the Martian seasonal pressure cycle. By extending the range of the calculated particle

  2. Regulation of Rad51-Mediated Homologous Recombination by BRCA2, DSS1 and RAD52

    DEFF Research Database (Denmark)

    Rants, Louise Olthaver Juhl

    Homologous recombination (HR) provides a mechanism to restore integrity and maintain stability of the genetic material. HR is a major pathway for repair of DNA double-strand breaks (DSB), recovery of broken replication forks and generation of meiotic crossovers. The defining step in HR is homolog......Homologous recombination (HR) provides a mechanism to restore integrity and maintain stability of the genetic material. HR is a major pathway for repair of DNA double-strand breaks (DSB), recovery of broken replication forks and generation of meiotic crossovers. The defining step in HR...... is homologous strand exchange directed by the RecA-related recombinase Rad51. BRCA2 participates in HR by mediating Rad51 homology-directed repair. Both BRCA2 and Rad51 are essential for HR, DNA repair, and the maintenance of genome stability. In the present study, we seek to understand the mechanism of BRCA2...... with RAD52-mediated repair at sites of CPT-induced DNA damage. The synthetic lethality approach using RAD52 small molecule inhibitors in brca-deficient cancers is a promising therapeutic strategy for cancer treatment....

  3. Thermal conductivity of (Np0.20Pu0.50Am0.25Cm0.05)O2−x solid solutions

    International Nuclear Information System (INIS)

    Nishi, Tsuyoshi; Takano, Masahide; Akabori, Mitsuo; Arai, Yasuo

    2013-01-01

    Highlights: • Thermal conductivity of (Np 0.20 Pu 0.50 Am 0.25 Cm 0.05 )O 2−x was evaluated. • Dependence of thermal conductivity on storage time was clarified. • Results were discussed with the lattice expansion model by self-irradiation. • After annealing at 1423 K in vacuum, thermal conductivity returned. -- Abstract: The authors prepared the sintered sample of (Np 0.20 Pu 0.50 Am 0.25 Cm 0.05 )O 2−x (2 − x = 1.98, 1.96) solid solution and evaluated the dependence of the thermal conductivity on storage time and temperature. The heat capacity of (Np 0.20 Pu 0.50 Am 0.25 Cm 0.05 )O 1.98 was measured between 324 and 1082 K by a drop calorimetry. The thermal diffusivity of (Np 0.20 Pu 0.50 Am 0.25 Cm 0.05 )O 1.98 was measured when the storage time became 48, 216, 720 and 1584 h and that of (Np 0.20 Pu 0.50 Am 0.25 Cm 0.05 )O 1.96 was measured when the storage time became 0,528 and 1386 h. In this study, the latter sample was annealed at 1423 K in vacuum with background pressure of less than 2.0 × 10 −4 Pa just after the measurement on the storage time, 1386 h. The thermal diffusivity of (Np 0.20 Pu 0.50 Am 0.25 Cm 0.05 )O 1.96 just after annealing returned to the values of the storage time, 0 h. This result reveals the thermal recovery behavior by annealing. The thermal conductivity of (Np 0.20 Pu 0.50 Am 0.25 Cm 0.05 )O 2−x was determined from the measured thermal diffusivity, heat capacity and bulk density. The thermal conductivity of (Np 0.20 Pu 0.50 Am 0.25 Cm 0.05 )O 2−x exponentially decreased with increasing storage time. This result suggested that the decrease of the thermal conductivity was attributed to the accumulation of lattice defects caused by self-irradiation

  4. Classification of areas considering equivalent doses due to radon, indoors in the Institute of Chemical, Biological, Radiological and Nuclear Defense (IDQBRN); Classificação de áreas considerando as doses equivalentes devido a radônio, em ambientes fechados no Instituto de Defesa Química, Biológica, Radiológica e Nuclear (IDQBRN)

    Energy Technology Data Exchange (ETDEWEB)

    Arbach, Mayara N.; Soares, Alexandre B., E-mail: mayaraarbach@gmail.com, E-mail: alexandrebaso@globo.com [Instituto de Radioproteção e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Alves, Rex N.; Cardoso, Domingos D’ O.; Júnior, Walter José. G., E-mail: rexnazare@ime.eb.br, E-mail: domin@ime.eb.br, E-mail: walter_guimaraes@ime.eb.br [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil)

    2017-07-01

    The human being is subject to several sources of natural radiation, mainly radon, belonging to the radioactive decay chain of uranium and thorium. At the study site, approximately 3.3 tons of uranium with natural concentration are stored. This fact, which generated the concern about the occupational dose levels of the IOE's of the facility, because its effective dose will have the increase due to the equivalent dose from the exposure to radon. The measurements took place: in the uranium deposit; in an adjoining room and at the control point. According to the norm CNEN - NN 3.01 and considering the existing radon concentrations in the three environments it was concluded that: the uranium deposit room is considered a controlled area; the control point a free area and the contiguous room, a supervised area.

  5. RIVER-RAD: A computer code for simulating the transport of radionuclides in rivers

    International Nuclear Information System (INIS)

    Hetrick, D.M.; McDowell-Boyer, L.M.; Sjoreen, A.L.; Thorne, D.J.; Patterson, M.R.

    1992-11-01

    A screening-level model, RIVER-RAD, has been developed to assess the potential fate of radionuclides released to rivers. The model is simplified in nature and is intended to provide guidance in determining the potential importance of the surface water pathway, relevant transport mechanisms, and key radionuclides in estimating radiological dose to man. The purpose of this report is to provide a description of the model and a user's manual for the FORTRAN computer code

  6. Functional roles for Rad9 in prostate cancer

    International Nuclear Information System (INIS)

    Lieberman, H.B.; Broustas, C.G.

    2012-01-01

    The goal of this work is to understand the mechanistic relationship between high levels of Rad9 protein and prostate cancer. The study is based on several findings suggesting a role for Rad9 in this disease. Rad9 has all the hallmark features of an oncogene or tumor suppressor. It regulates genomic stability, multiple cell cycle checkpoints, apoptosis and DNA repair. In addition, it can transactivate downstream target genes via direct interaction with promoter DNA sequences. We found Rad9 protein levels were very high in prostate cancer cell lines. Furthermore, we examined 52 primary normal prostate and 339 prostate cancer specimens for Rad9 protein by immunohistochemical staining. Statistical significance for Rad9 positive staining versus cancer, and stain intensity versus Stage were tested. We get a p-value of <0.001 when comparing percentage positive by cancer Stage, or stain intensity by cancer Stage. Based on these data, we sought to define the nature of the relationship between Rad9 and prostate cancer. We demonstrate that Rad9 acts as an oncogene in prostate cancer by playing a critical role in tumor formation in a mouse xenograph model. We also show that Rad9 is important for cellular phenotypes essential for metastasis, including tumor cell migration, invasion and resistance to programmed cell death after detachment from extracellular matrix. Therefore, Rad9 is critical for several aspects of prostate tumor progression, and could serve as a novel target for anti-cancer therapy

  7. Targeting Rad50 sensitizes human nasopharyngeal carcinoma cells to radiotherapy

    International Nuclear Information System (INIS)

    Chang, Lihong; Huang, Jiancong; Wang, Kai; Li, Jingjia; Yan, Ruicheng; Zhu, Ling; Ye, Jin; Wu, Xifu; Zhuang, Shimin; Li, Daqing; Zhang, Gehua

    2016-01-01

    The Mre11-Rad50-Nbs1 (MRN) complex is well known for its crucial role in initiating DNA double strand breaks (DSBs) repair pathways to resistant irradiation (IR) injury and thus facilitating radioresistance which severely reduces radiocurability of nasopharyngeal cancer (NPC). Targeting native cellular MRN function would sensitize NPC cells to IR. A recombinant adenovirus containing a mutant Rad50 gene (Ad-RAD50) expressing Rad50 zinc hook domain but lacking the ATPase domain and the Mre11 interaction domain was constructed to disrupt native cellular MRN functions. The effects of Ad-RAD50 on the MRN functions were assessed in NPC cells lines using western blot, co-immunoprecipitation and confocal microscopy analyses. The increased radiosensitivity of transient Ad-RAD50 to IR was examined in NPC cells, including MTT assay, colony formation. The molecular mechanisms of radiosensitization were confirmed by neutral comet assay and western bolts. Nude mice subcutaneous injection, tumor growth curve and TUNEL assay were used to evaluate tumor regression and apoptosis in vivo. Rad50 is remarkably upregulated in NPC cells after IR, implying the critical role of Rad50 in MRN functions. The transient expression of this mutant Rad50 decreased the levels of native cellular Rad50, Mre11 and Nbs1, weakened the interactions among these proteins, abrogated the G2/M arrest induced by DSBs and reduced the DNA repair ability in NPC cells. A combination of IR and mutant RAD50 therapy produced significant tumor cytotoxicity in vitro, with a corresponding increase in DNA damage, prevented proliferation and cell viability. Furthermore, Ad-RAD50 sensitized NPC cells to IR by causing dramatic tumor regression and inducing apoptosis in vivo. Our findings define a novel therapeutic approach to NPC radiosensitization via targeted native cellular Rad50 disruption. The online version of this article (doi:10.1186/s12885-016-2190-8) contains supplementary material, which is available to

  8. Development of the Computer Code to Determine an Individual Radionuclides in the Rad-wastes Container for Ulchin Units 3 and 4

    Energy Technology Data Exchange (ETDEWEB)

    Kang, D.W.; Chi, J.H.; Goh, E.O. [Korea Electric Power Research Institute, Taejon (Korea)

    2001-07-01

    A computer program, RASSAY was developed to evaluate accurately the activities of various nuclides in the rad-waste container for Ulchin units 3 and 4. This is the final report of the project, {sup D}evelopment of the Computer Code to Determine an Individual Radionuclides in the Rad-wastes Container for Ulchin Units 3 and 4 and includes the followings; 1) Structure of the computer code, RASSAY 2) An example of surface dose calculation by computer simulation using MCNP code 3) Methods of sampling and activity measurement of various Rad-wastes. (author). 21 refs., 35 figs., 6 tabs.

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

    International Nuclear Information System (INIS)

    Wang Wen; Hu Liqin; Cheng Mengyun; Long Pengcheng

    2015-01-01

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

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

    International Nuclear Information System (INIS)

    Ghosh, Somnath; Krishna, Malini

    2012-01-01

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

  11. Regeneration of CFUs in the marrow of mice exposed to 300 rads after having recovered from 950 rads

    International Nuclear Information System (INIS)

    Kedo, A.; Barone, J.; Fried, W.

    1976-01-01

    Exposure to 950 rads 60 Co radiation has been reported to cause long-lasting damage to the hematopoietic stroma (HS), although the size of the CFUs population recovers to pre-irradiation levels. In these studies HS damage was detected only after subcutaneously implanting the femurs of the irradiated mice into syngeneic hosts. To exclude the possibility that what was considered to be HS damage was merely caused by artifacts due to the process of implantation in a new host, the rate of regeneration of CFUs in mice which had recovered from 950 rads prior to receiving 300 rads 60 Co radiation (950 + 300 rads group) was compared with that of mice which received only 300 rads (0 + 300 rads group). The CFUs population in the 950 + 300 rads group grew exponentially for 2 weeks at a rate which did not differ significantly from that of CFUs in the 0 + 300 rads group. However, the rate of CFUs growth reached a plateau before full recovery was achieved in contrast to that in the 0 + 300 rads mice. It was therefore concluded that the incomplete regeneration of CFUs in the marrows of 950 + 300 rads mice was most likely caused by X-irradiation-induced damage to the HS rather than damage to the inherent repopulation potential of the CFUs per se. (author)

  12. Split dose recovery studies using homologous recombination deficient gene knockout chicken B lymphocyte cells

    International Nuclear Information System (INIS)

    Rao, B.S.S.; Tano, Kaori; Utsumi, Hiroshi; Takeda, Shunichi

    2007-01-01

    To understand the role of proteins involved in double strand breaks (DSB) repair modulating sublethal damage (SLD) recovery, chicken B lymphoma (DT 40) cell lines either proficient or deficient in RAD52, XRCC2, XRCC3, RAD51C and RAD51D were subjected to fractionated irradiation and their survival curves charted. Survival curves of both WT DT40 and RAD52 -/- cells had a big shoulder while all the other cells exhibited small shoulders. However, at the higher doses of radiation, RAD51C -/- cells displayed hypersensitivity comparable to the data obtained for the homologous recombination deficient RAD54 -/- cells. Repair of SLD was measured as an increase in survival after a split dose irradiation with an interval of incubation between the radiation doses. All the cell lines (parental DT40 and genetic knockout cell lines viz., RAD52 -/- , XRCC2 -/- XRCC3 -/- RAD51C -/- and RAD51D -/- ) used in this study demonstrated a typical split-dose recovery capacity with a specific peak, which varied depending on the cell type. The maximum survival of WT DT40 and RAD52 -/- was reached at about 1-2 hours after the first dose of radiation and then decreased to a minimum thereafter (5 h). The increase in the survival peaked once again by about 8 hours. The survival trends observed in XRCC2 -/- , XRCC3 -/- , RAD51C -/- and RAD51D -/- knockout cells were also similar, except for the difference in the initial delay of a peak survival for RAD51D -/- and lower survival ratios. The second phase of increase in the survival in these cell lines was much slower in XRCC2 -/- , XRCC3 -/- , RAD51C -/- nd RAD51D -/- and further delayed when compared with that of RAD52 -/- and parental DT40 cells suggesting a dependence on their cell cycle kinetics. This study demonstrates that the participation of RAD52, XRCC2, XRCC3, RAD51C and RAD51D in the DSB repair via homologous recombination is of less importance in comparison to RAD54, as RAD54 deficient cells demonstrated complete absence of SLD recovery

  13. Correlation of RAD51 and radiosensitization of methotrexate

    International Nuclear Information System (INIS)

    Du Liqing; Bai Jianqiang; Liu Qiang; Wang Yan; Zhao Peng; Chen Fenghua; Wang Hong; Fan Feiyue

    2012-01-01

    Objective: To evaluate the correlation between homologous recombination repair protein RAD51 and methotrexate-enhanced radiosensitivity. Methods: Western blot and RT-PCR assays were used to detect RAD51 expression in HOS osteosarcoma cells exposed to γ-ray irradiation alone and in combination with methotrexate. Colony formation assay was used to test the survival fraction of HOS cells exposed to γ-rays and methotrexate. Results: Methotrexate inhibited both protein and RNA expressions of RAD51, and the combination of radiation and methotrexate enhanced the inhibition of RAD51 expression. Moreover, transfection of cells with RAD51 gene decreased cellular sensitivity to methotrexate and γ-rays. The sensitizer enhancement ratios after irradiation in combination with methotrexate were 1.51 and 0.99, respectively. Methotrexate was a preferred radiosensitizer to HOS cell. Conclusions: RAD51 might be involved in the methotrexate-enhanced radiosensitivity. (authors)

  14. Nonvolatile Rad-Hard Holographic Memory

    Science.gov (United States)

    Chao, Tien-Hsin; Zhou, Han-Ying; Reyes, George; Dragoi, Danut; Hanna, Jay

    2001-01-01

    We are investigating a nonvolatile radiation-hardened (rad-hard) holographic memory technology. Recently, a compact holographic data storage (CHDS) breadboard utilizing an innovative electro-optic scanner has been built and demonstrated for high-speed holographic data storage and retrieval. The successful integration of this holographic memory breadboard has paved the way for follow-on radiation resistance test of the photorefractive (PR) crystal, Fe:LiNbO3. We have also started the investigation of using two-photon PR crystals that are doubly doped with atoms of iron group (Ti, Cr, Mn, Cu) and of rare-earth group (Nd, Tb) for nonvolatile holographic recordings.

  15. Wallac automatic alarm dosimeter type RAD21

    International Nuclear Information System (INIS)

    Burgess, P. H.; Iles, W.J.

    1980-02-01

    The Automatic Alarm Dosimeter type RAD 21 is a batterypowered personal dosemeter and exposure rate alarm monitor, designed to be worn on the body, covering an exposure range from 0.1 to 999.9 mR and has an audible alarm which can be pre-set over the range 1 mR h -1 to 250 mR h -1 . The instrument is designed to measure x- and γ radiation over the energy range 50 keV to 3 MeV. The facilities and controls, the radiation, electrical, environmental and mechanical characteristics, and the manual, have been evaluated. (U.K.)

  16. Astaxanthin down-regulates Rad51 expression via inactivation of AKT kinase to enhance mitomycin C-induced cytotoxicity in human non-small cell lung cancer cells.

    Science.gov (United States)

    Ko, Jen-Chung; Chen, Jyh-Cheng; Wang, Tai-Jing; Zheng, Hao-Yu; Chen, Wen-Ching; Chang, Po-Yuan; Lin, Yun-Wei

    2016-04-01

    Astaxanthin has been demonstrated to exhibit a wide range of beneficial effects, including anti-inflammatory and anti-cancer properties. However, the molecular mechanism of astaxanthin-induced cytotoxicity in non-small cell lung cancer (NSCLC) cells has not been identified. Rad51 plays a central role in homologous recombination, and studies show that chemo-resistant carcinomas exhibit high levels of Rad51 expression. In this study, astaxanthin treatment inhibited cell viability and proliferation of two NSCLC cells, A549 and H1703. Astaxanthin treatment (2.5-20 μM) decreased Rad51 expression and phospho-AKT(Ser473) protein level in a time and dose-dependent manner. Furthermore, expression of constitutively active AKT (AKT-CA) vector rescued the decreased Rad51 mRNA and protein levels in astaxanthin-treated NSCLC cells. Combined treatment with phosphatidylinositol 3-kinase (PI3K) inhibitors (LY294002 or wortmannin) further decreased the Rad51 expression in astaxanthin-exposed A549 and H1703 cells. Knockdown of Rad51 expression by transfection with si-Rad51 RNA or cotreatment with LY294002 further enhanced the cytotoxicity and cell growth inhibition of astaxanthin. Additionally, mitomycin C (MMC) as an anti-tumor antibiotic is widely used in clinical NSCLC chemotherapy. Combination of MMC and astaxanthin synergistically resulted in cytotoxicity and cell growth inhibition in NSCLC cells, accompanied with reduced phospho-AKT(Ser473) level and Rad51 expression. Overexpression of AKT-CA or Flag-tagged Rad51 reversed the astaxanthin and MMC-induced synergistic cytotoxicity. In contrast, pretreatment with LY294002 further decreased the cell viability in astaxanthin and MMC co-treated cells. In conclusion, astaxanthin enhances MMC-induced cytotoxicity by decreasing Rad51 expression and AKT activation. These findings may provide rationale to combine astaxanthin with MMC for the treatment of NSCLC. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. RadCat 2.0 User Guide.

    Energy Technology Data Exchange (ETDEWEB)

    Osborn, Douglas.; Weiner, Ruth F.; Mills, George Scott; Hamp, Steve C.; O' Donnell, Brandon, M.; Orcutt, David J.; Heames, Terence J.; Hinojosa, Daniel

    2005-01-01

    This document provides a detailed discussion and a guide for the use of the RadCat 2.0 Graphical User Interface input file generator for the RADTRAN 5.5 code. The differences between RadCat 2.0 and RadCat 1.0 can be attributed to the differences between RADTRAN 5 and RADTRAN 5.5 as well as clarification for some of the input parameters. 3

  18. Rad9 Has a Functional Role in Human Prostate Carcinogenesis

    Science.gov (United States)

    Zhu, Aiping; Zhang, Charles Xia; Lieberman, Howard B.

    2013-01-01

    Prostate cancer is currently the most common type of neoplasm found in American men, other than skin cancer, and is the second leading cause of cancer death in males. Because cell cycle checkpoint proteins stabilize the genome, the relationship of one such protein, Rad9, to prostate cancer was investigated. We found that four prostate cancer cell lines (CWR22, DU145, LNCaP, and PC-3), relative to PrEC normal prostate cells, have aberrantly high levels of Rad9 protein. The 3′-end region of intron 2 of Rad9 in DU145 cells is hypermethylated at CpG islands, and treatment with 5′-aza-2′-deoxycytidine restores near-normal levels of methylation and reduces Rad9 protein abundance. Southern blot analyses indicate that PC-3 cells contain an amplified Rad9 copy number. Therefore, we provide evidence that Rad9 levels are high in prostate cancer cells due at least in part to aberrant methylation or gene amplification. The effectiveness of small interfering RNA to lower Rad9 protein levels in CWR22, DU145, and PC-3 cells correlated with reduction of tumorigenicity in nude mice, indicating that Rad9 actively contributes to the disease. Rad9 protein levels were high in 153 of 339 human prostate tumor biopsy samples examined and detectable in only 2 of 52 noncancerous prostate tissues. There was a strong correlation between Rad9 protein abundance and cancer stage. Rad9 protein level can thus provide a biomarker for advanced prostate cancer and is causally related to the disease, suggesting the potential for developing novel diagnostic, prognostic, and therapeutic tools based on detection or manipulation of Rad9 protein abundance. PMID:18316588

  19. Effect of dose rate and exposure time on the stimulation effect of tube growth of Pinus sylvestris pollen

    International Nuclear Information System (INIS)

    Zelles, L.; Fendrik, I.; Technische Univ. Hannover

    1975-01-01

    The stimulating effect of ionizing radiation in respect to dose rate and exposure time was studied using the tube growth of Pinus silvestris pollen. Stimulation was registered with a small dose (50 rad) supplied at low dose rates (0.5; 1.0; 3.0 and 5.0 rad/sec) and with higher doses (300; 800 and 1,400 rad) supplied at higher dose rates (10; 40 and 50 rad/sec). This suggests that only the exposure time is of importance for radiation-induced stimulation provided that the exposure time does not exceed 100 sec. (orig.) [de

  20. Space Weather at Mars: MAVEN and MSL/RAD Observations of CME and SEP Events

    Science.gov (United States)

    Lee, C. O.; Ehresmann, B.; Lillis, R. J.; Dunn, P.; Rahmati, A.; Larson, D. E.; Guo, J.; Zeitlin, C.; Luhmann, J. G.; Halekas, J. S.; Espley, J. R.; Thiemann, E.; Hassler, D.

    2017-12-01

    While MAVEN have been observing the space weather conditions driven by ICMEs and SEPs in orbit around Mars, MSL/RAD have been measuring the surface radiation environment due to E > 150 MeV/nuc SEPs and the higher-energy galactic cosmic rays. The suite of MAVEN instruments measuring the particles (SEP), plasma (SWIA) and fields (MAG) information provides detailed local space weather information regarding the solar activity-related fluctuations in the measured surface dose rates. At the same time, the related enhancements in the RAD surface dose rates indicate the degree to which the SEPs affect the lower atmosphere and surface. We will present an overview of the MAVEN observations together with the MSL/RAD measurements and focus our discussion on a number of space weather events driven by CMEs and SEPs. During the March 2015 solar storm period, a succession of CMEs produced intense SEP proton fluxes that were detected by MAVEN/SEP in the 20 keV to 6 MeV detected energy channels. At higher energies, MAVEN/SEP record `FTO' SEP events that were triggered by > 13 MeV energetic protons passing through all three silicon detector layers (Front, Thick, and Open). Using the detector response matrix for an FTO event (incident energy vs detected energy), the minimum incident energy of the SEP protons observed in March 2015 was inferred to be > 40 MeV. The lack of any notable enhancements in the surface dose rate by MSL/RAD suggests that the highest incident energies of the SEP protons were 150 MeV SEP protons impacted the Martian atmosphere and surface. The source of the October 2015 SEP event was probably the CME that erupted near the solar west limb with respect to the Sun-Mars line. As part of the discussion, we will also show solar-heliospheric observations from near-Earth assets together with WSA-Enlil-cone results for some global heliospheric context.

  1. Improvement of CMOS VLSI rad tolerance by processing technics

    International Nuclear Information System (INIS)

    Guyomard, D.; Desoutter, I.

    1986-01-01

    The following study concerns the development of integrated circuits for fields requiring only relatively low radiation tolerance levels, and especially for the civil spatial district area. Process modifications constitute our basic study. They have been carried into effects. Our work and main results are reported in this paper. Well known 2.5 and 3 μm CMOS technologies are under our concern. A first set of modifications enables us to double the cumulative dose tolerance of a 4 Kbit SRAM, keeping at the same time the same kind of damage. We obtain memories which tolerate radiation doses as high as 16 KRad(Si). Repetitivity of the results, linked to the quality assurance of this specific circuit, is reported here. A second set of modifications concerns the processing of gate array. In particular, the choice of the silicon substrate type, (epitaxy substrate), is under investigation. On the other hand, a complete study of a test vehicule allows us to accurately measure the rad tolerance of various components of the Cell library [fr

  2. A dedicated BI-RADS training programme: Effect on the inter-observer variation among screening radiologists

    International Nuclear Information System (INIS)

    Timmers, J.M.H.; Doorne-Nagtegaal, H.J. van; Verbeek, A.L.M.; Heeten, G.J. den; Broeders, M.J.M.

    2012-01-01

    Introduction: The Breast Imaging Reporting and Data System (BI-RADS) was introduced in the Dutch breast cancer screening programme to improve communication between medical specialists. Following introduction, a substantial variation in the use of the BI-RADS lexicon for final assessment categories was noted among screening radiologists. We set up a dedicated training programme to reduce this variation. This study evaluates whether this programme was effective. Materials and methods: Two comparable test sets were read before and after completion of the training programme. Each set contained 30 screening mammograms of referred women selected from screening practice. The sets were read by 25 experienced and 30 new screening radiologists. Cohen's kappa (κ) was used to calculate the inter-observer agreement. The BI-RADS 2003 version was implemented in the screening programme as the BI-RADS 2008 version requires the availability of diagnostic work-up, and this is unavailable. Results: The inter-observer agreement of all participating radiologists (n = 55) with the expert panel increased from a pre-training κ-value of 0.44 to a post-training κ-value of 0.48 (p = 0.14). The inter-observer agreement of the new screening radiologists (n = 30) with the expert panel increased from κ = 0.41 to κ = 0.50 (p = 0.01), whereas there was no difference in agreement among the 25 experienced radiologists (from κ = 0.48 to κ = 0.46, p = 0.60). Conclusion: Our training programme in the BI-RADS lexicon resulted in a significant improvement of agreement among new screening radiologists. Overall, the agreement among radiologists was moderate (guidelines Landis and Koch). This is in line with results found in the literature

  3. Roles of C-Terminal Region of Yeast and Human Rad52 in Rad51-Nucleoprotein Filament Formation and ssDNA Annealing.

    Directory of Open Access Journals (Sweden)

    Nilesh V Khade

    Full Text Available Yeast Rad52 (yRad52 has two important functions at homologous DNA recombination (HR; annealing complementary single-strand DNA (ssDNA molecules and recruiting Rad51 recombinase onto ssDNA (recombination mediator activity. Its human homolog (hRAD52 has a lesser role in HR, and apparently lacks mediator activity. Here we show that yRad52 can load human Rad51 (hRAD51 onto ssDNA complexed with yeast RPA in vitro. This is biochemically equivalent to mediator activity because it depends on the C-terminal Rad51-binding region of yRad52 and on functional Rad52-RPA interaction. It has been reported that the N-terminal two thirds of both yRad52 and hRAD52 is essential for binding to and annealing ssDNA. Although a second DNA binding region has been found in the C-terminal region of yRad52, its role in ssDNA annealing is not clear. In this paper, we also show that the C-terminal region of yRad52, but not of hRAD52, is involved in ssDNA annealing. This suggests that the second DNA binding site is required for the efficient ssDNA annealing by yRad52. We propose an updated model of Rad52-mediated ssDNA annealing.

  4. Differential expression and requirements for Schizosaccharomyces pombe RAD52 homologs in DNA repair and recombination

    OpenAIRE

    van den Bosch, Michael; Zonneveld, José B. M.; Vreeken, Kees; de Vries, Femke A. T.; Lohman, Paul H. M.; Pastink, Albert

    2002-01-01

    In fission yeast two RAD52 homologs have been identified, rad22A+ and rad22B+. Two-hybrid experiments and GST pull-down assays revealed physical interaction between Rad22A and Rad22B, which is dependent on the N-terminal regions. Interaction with Rhp51 is dependent on the C-terminal parts of either protein. Both Rad22A and Rad22B also interact with RPA. The expression of rad22B+ in mitotically dividing cells is very low in comparison with rad22A+ but is strongly enhanced after induction of me...

  5. Avaliação das propriedades do Ba0,50Sr0,50Co0,80Fe0,20O3-d para células a combustível de óxido sólido de temperatura intermediária obtido pelo método citratos-EDTA Evaluation of the properties of Ba0,50Sr0.50Co0.80Fe0.20O3-d obtained by the citrate-EDTA method for intermediate temperature solid oxide fuel cell

    Directory of Open Access Journals (Sweden)

    E. Bonturim

    2013-03-01

    Full Text Available Ba0,50Sr0,50Co0,80Fe0,20O3-d (BSCF apresenta propriedades físicas, químicas e microestruturais adequadas para compor o cátodo de uma célula a combustível de óxido sólido de temperatura intermediária (ITSOFC. Este trabalho tem por objetivo a síntese e a caracterização do BSCF obtido pelo método dos citrados-EDTA. Os resultados obtidos por difração de raios X (DRX indicaram fases secundárias para o material calcinado a 700 e 800 ºC e fase única com estrutura cristalina do tipo perovskita para 900 ºC. As micrografias obtidas por microscopia eletrônica de varredura dos particulados evidenciou a formação de aglomerados de tamanho Ba0.50Sr0.50Co0.80Fe0.20O3-d (BSCF presents physical, chemical and microstructural properties suitable to form the cathode of Intermediate Temperature Solid Oxide Fuel Cell (ITSOFC. This work aims the synthesis and characterization of BSCF, obtained by the citrate-EDTA method. The X-ray diffraction results indicate secondary phases for the material calcined at 700 and 800 °C and single phase with perovskite crystalline structure at 900 °C. The SEM-FEG particles micrographs show the formation of < 20 µm clusters. The dilatometric analysis of pellets indicates the sintering temperature at ~ 1050 °C. XRD results of the sintered samples show perovskite single phase. The SEM micrographs confirmed the formation of higher porosity in the samples sintered at 1000 °C/1 h using powders calcined at 900 °C.

  6. Magnetization reversal and tunable exchange bias in GdCr{sub 1−x}Mn{sub x}O{sub 3} (x=0−0.50)

    Energy Technology Data Exchange (ETDEWEB)

    Dash, Bibhuti B.; Ravi, S., E-mail: sravi@iitg.ernet.in

    2017-05-01

    Single phase samples of GdCr{sub 1-x}Mn{sub x}O{sub 3} (x=0−0.50) were prepared and their magnetic properties were studied by measuring temperature and field variations of magnetization. The Neel temperature, T{sub N} is found to decrease from T{sub N}=174 K for x=0 to 91 K for x=0.50. The magnetization reversal persists upto 5 at% of Mn substitution with a magnetic compensation temperature, T{sub comp} of 136 K and 139 K for x=0 and 0.05 respectively. However, spin reorientation induced magnetization reversal emerges for x=0.40 and 0.50 samples around 30 K. Tunable positive and negative exchange bias fields in the range of −1.0 kOe to +1.6 kOe have been observed. The origin of magnetization reversal and exchange bias field is explained in terms of antiparallel alignment of canted ferromagnetic component of Cr{sup 3+} ions and the paramagnetic moments of Gd{sup 3+} and Mn{sup 3+} ions under the influence of negative internal field due to antiferromagnetically ordered Cr{sup 3+} ions. - Highlights: • Magnetization reversal and bipolar switching in Mn substituted GdCrO{sub 3} • Tunable exchange bias field in the range of −1.0 kOe to +1.6 kOe. • Low temperature spin reorientation transition is observed.

  7. Assay for Human Rad51-Mediated DNA Displacement Loop Formation

    OpenAIRE

    sprotocols

    2014-01-01

    Authors: Steven Raynard and Patrick Sung Corresponding author ([]()) ### INTRODUCTION Homologous recombination is an important mechanism for the repair of damaged chromosomes, for preventing the demise of damaged replication forks, and for several other aspects of chromosome metabolism and maintenance. The homologous recombination reaction is mediated by the Rad51 recombinase. In the presence of ATP, Rad51 polymerizes on single-stranded D...

  8. Effects of sublethal doses of gamma radiation on the developing rat brain

    International Nuclear Information System (INIS)

    Cerda, H.; Carlsson, J.; Larsson, B.; Saefwenberg, J.O.

    1975-01-01

    Newborn rats were irradiated with 60 Co gamma rays. Doses of 0, 80 or 160 rads were given to the whole body. The whole body and brain weights, DNA and RNA contents of the brain and 3 H-thymidine or 3 H-uridine incorporated by the brain were measured at 5, 10 or 15 days after birth. A dose of 160 rads produced clear alterations in the brain but no clear effects could be detected when 80 rads were given. (author)

  9. Planning the rad waste repository - Croatian case

    International Nuclear Information System (INIS)

    Kucar Dragicevic, S.; Subasic, D.; Lokner, V.

    1996-01-01

    Radioactive waste is generated in Croatia from various nuclear applications as well as from the Krsko NPP (Slovenian and Croatian joint venture facility). The national programme on radioactive waste management is aimed at straightening existing infrastructure, establishing new (more transparent) system of responsibilities and development of new legislation. The siting of LL/ILW repository is important segments of the whole radioactive waste management cycle. The status and efficiency of the rad waste management infrastructure in the country have the significant influence on all the activities related to the project of repository construction - from the very first phases of preliminary planning and background preparations to advanced phases of the project development. The present status of the Croatian national radioactive waste infrastructure and its influence on the repository project are presented. The role of national legislation and institutional framework are specially discussed. (author)

  10. RadCon Occurrence Reporting Simplified

    International Nuclear Information System (INIS)

    Denham, D. H.

    1999-01-01

    This narrative and accompanying diagrams provide a simplified summary of the RadCon Occurrence Reporting criteria to allow Environmental Restoration Contractor (ERC) staff to efficiently recognize occurrences and to effectively initiate the implementation of the requirements of U.S. Department of Energy (DOE) Order 232.1A, Occurrence Reporting and Processing of Operations Information, and of the ERC criteria defined in BHI-MA-02, ERC Project Procedures, Procedure 2.6, ''Occurrence Investigation and Reporting.'' These directives promote timely identification, categorization, notification, and reporting to DOE and ERC management of reportable occurrences at DOE-owned or -operated facilities that could (1) affect health and safety of the public, (2) seriously impact the intended purpose of DOE facilities, (3) adversely affect the credibility of DOE, or (4) have a noticeable adverse effect on the environment

  11. RadVel: The Radial Velocity Modeling Toolkit

    Science.gov (United States)

    Fulton, Benjamin J.; Petigura, Erik A.; Blunt, Sarah; Sinukoff, Evan

    2018-04-01

    RadVel is an open-source Python package for modeling Keplerian orbits in radial velocity (RV) timeseries. RadVel provides a convenient framework to fit RVs using maximum a posteriori optimization and to compute robust confidence intervals by sampling the posterior probability density via Markov Chain Monte Carlo (MCMC). RadVel allows users to float or fix parameters, impose priors, and perform Bayesian model comparison. We have implemented real-time MCMC convergence tests to ensure adequate sampling of the posterior. RadVel can output a number of publication-quality plots and tables. Users may interface with RadVel through a convenient command-line interface or directly from Python. The code is object-oriented and thus naturally extensible. We encourage contributions from the community. Documentation is available at http://radvel.readthedocs.io.

  12. The SRS2 suppressor of rad6 mutations of Saccharomyces cerevisiae acts by channeling DNA lesions into the RAD52 DNA repair pathway

    International Nuclear Information System (INIS)

    Schiestl, R.H.; Prakash, S.; Prakash, L.

    1990-01-01

    rad6 mutants of Saccharomyces cerevisiae are defective in the repair of damaged DNA, DNA damage induced mutagenesis, and sporulation. In order to identify genes that can substitute for RAD6 function, the authors have isolated genomic suppressors of the UV sensitivity of rad6 deletion (rad6Δ) mutations and show that they also suppress the γ-ray sensitivity but not the UV mutagenesis or sporulation defects of rad6. The suppressors show semidominance for suppression of UV sensitivity and dominance for suppression of γ-ray sensitivity. The six suppressor mutations they isolated are all alleles of the same locus and are also allelic to a previously described suppressor of the rad6-1 nonsense mutation, SRS2. They show that suppression of rad6Δ is dependent on the RAD52 recombinational repair pathway since suppression is not observed in the rad6Δ SRS2 strain containing an additional mutation in either the RAD51, RAD52, RAD54, RAD55 or RAD57 genes. Possible mechanisms by which SRS2 may channel unrepaired DNA lesions into the RAD52 DNA repair pathway are discussed

  13. Mongoose: Creation of a Rad-Hard MIPS R3000

    Science.gov (United States)

    Lincoln, Dan; Smith, Brian

    1993-01-01

    This paper describes the development of a 32 Bit, full MIPS R3000 code-compatible Rad-Hard CPU, code named Mongoose. Mongoose progressed from contract award, through the design cycle, to operational silicon in 12 months to meet a space mission for NASA. The goal was the creation of a fully static device capable of operation to the maximum Mil-883 derated speed, worst-case post-rad exposure with full operational integrity. This included consideration of features for functional enhancements relating to mission compatibility and removal of commercial practices not supported by Rad-Hard technology. 'Mongoose' developed from an evolution of LSI Logic's MIPS-I embedded processor, LR33000, code named Cobra, to its Rad-Hard 'equivalent', Mongoose. The term 'equivalent' is used to infer that the core of the processor is functionally identical, allowing the same use and optimizations of the MIPS-I Instruction Set software tool suite for compilation, software program trace, etc. This activity was started in September of 1991 under a contract from NASA-Goddard Space Flight Center (GSFC)-Flight Data Systems. The approach affected a teaming of NASA-GSFC for program development, LSI Logic for system and ASIC design coupled with the Rad-Hard process technology, and Harris (GASD) for Rad-Hard microprocessor design expertise. The program culminated with the generation of Rad-Hard Mongoose prototypes one year later.

  14. Experience with the biofragmentable anastomotic ring (BAR) in bowel preoperatively irradiated with 6000 rad

    Energy Technology Data Exchange (ETDEWEB)

    Croston, J.K.; Jacobs, D.M.; Kelly, P.H.; Feeney, D.A.; Johnston, G.R.; Strom, R.L.; Bubrick, M.P. (Hennepin County Medical Center, Minneapolis, MN (USA))

    1990-03-01

    Previous studies from the authors' laboratory using the biodegradable anastomotic ring (BAR) have demonstrated the safety of this device in animals irradiated preoperatively with the equivalent of 5000 rad; sutured, stapled, and BAR anastomoses all had leak rates of 10 percent or less in this setting. This study was undertaken to assess the safety of the BAR after irradiation with the equivalent of 6000 rad. Thirteen mongrel dogs underwent preoperative irradiation to the rectum and rectosigmoid, receiving 6000 rad according to the nominal standard dose equation. After a three-week rest period, each dog underwent anterior resection of the rectosigmoid and anastomosis with the BAR. The anastomoses were evaluated for early and late healing and anastomotic leaks. The results were compared with previous data from the authors' laboratory using an identical model. Radiographic leaks were found in 7 of 10 sutured anastomoses, 8 of 10 stapled anastomoses, and 3 of 13 BAR anastomoses (P less than 0.01). Comparative clinical leaks were 5 of 10 for sutured, 5 of 10 for stapled, and 3 of 13 for BAR anastomoses. These data suggest that the BAR may offer added safety to an anastomosis after preoperative irradiation. Whether this effect is due to the atraumatic technique of placing the device, improved blood flow to the anastomotic margins, or other factors, is still underdetermined.

  15. Experience with the biofragmentable anastomotic ring (BAR) in bowel preoperatively irradiated with 6000 rad

    International Nuclear Information System (INIS)

    Croston, J.K.; Jacobs, D.M.; Kelly, P.H.; Feeney, D.A.; Johnston, G.R.; Strom, R.L.; Bubrick, M.P.

    1990-01-01

    Previous studies from the authors' laboratory using the biodegradable anastomotic ring (BAR) have demonstrated the safety of this device in animals irradiated preoperatively with the equivalent of 5000 rad; sutured, stapled, and BAR anastomoses all had leak rates of 10 percent or less in this setting. This study was undertaken to assess the safety of the BAR after irradiation with the equivalent of 6000 rad. Thirteen mongrel dogs underwent preoperative irradiation to the rectum and rectosigmoid, receiving 6000 rad according to the nominal standard dose equation. After a three-week rest period, each dog underwent anterior resection of the rectosigmoid and anastomosis with the BAR. The anastomoses were evaluated for early and late healing and anastomotic leaks. The results were compared with previous data from the authors' laboratory using an identical model. Radiographic leaks were found in 7 of 10 sutured anastomoses, 8 of 10 stapled anastomoses, and 3 of 13 BAR anastomoses (P less than 0.01). Comparative clinical leaks were 5 of 10 for sutured, 5 of 10 for stapled, and 3 of 13 for BAR anastomoses. These data suggest that the BAR may offer added safety to an anastomosis after preoperative irradiation. Whether this effect is due to the atraumatic technique of placing the device, improved blood flow to the anastomotic margins, or other factors, is still underdetermined

  16. RAD52 Facilitates Mitotic DNA Synthesis Following Replication Stress

    DEFF Research Database (Denmark)

    Bhowmick, Rahul; Minocherhomji, Sheroy; Hickson, Ian D

    2016-01-01

    Homologous recombination (HR) is necessary to counteract DNA replication stress. Common fragile site (CFS) loci are particularly sensitive to replication stress and undergo pathological rearrangements in tumors. At these loci, replication stress frequently activates DNA repair synthesis in mitosis...... replication stress at CFS loci during S-phase. In contrast, MiDAS is RAD52 dependent, and RAD52 is required for the timely recruitment of MUS81 and POLD3 to CFSs in early mitosis. Our results provide further mechanistic insight into MiDAS and define a specific function for human RAD52. Furthermore, selective...

  17. Chromosome aberration yields in human lymphocytes induced by fractionated doses of x-radiation

    International Nuclear Information System (INIS)

    Purrott, R.J.; Reeder, E.

    1976-01-01

    Unstimulated (G 0 ) human peripheral blood lymphocytes were exposed at 37degC to doses of 200 or 500 rad of X-rays delivered in two equal fractions. The dose fractions were separated by intervals of up to 7 h in the 200 rad study and up to 48 h for 500 rad. In both studies the mean levels of dicentrics and total unstable aberrations began to decline when fractions were delivered with intervals of greater than 2 h. With 200 rad the yield had decreased to an additive baseline (i.e. equal to only twice the yield of a single 100-rad fraction) by an interval of 4 h. Following 500 rad the yield declined until 8 h and then remained 20% above the expected additive baseline even when 48 h separated the fractions. Possible explanations for this discrepancy are discussed. In a second experiment PHA stimulated lymphocyte cultures were exposed to 2 doses of 125 rad of X-rays up to 7 h apart in an attempt to demonstrate the late peak in aberration yield originally reported by Lane. Control cultures received unsplit doses of 250 rad at the time of the corresponding second 125-rad fraction. No evidence of a late peak in dicentric yield was observed. The yield remained approximately the same irrespective of the time interval between fractions but these split dose yields were significantly different from the accompanying unsplit controls

  18. Piezoelectric Ceramics of the (1 − x)Bi0.50Na0.50TiO3–xBa0.90Ca0.10TiO3 Lead-Free Solid Solution: Chemical Shift of the Morphotropic Phase Boundary, a Case Study for x = 0.06

    Science.gov (United States)

    Vivar-Ocampo, Rodrigo; Pardo, Lorena; Ávila, David; Morán, Emilio; González, Amador M.; Bucio, Lauro; Villafuerte-Castrejón, María-Elena

    2017-01-01

    Research and development of lead-free piezoelectric materials are still the hottest topics in the field of piezoelectricity. One of the most promising lead-free family of compounds to replace lead zirconate–titanate for actuators is that of Bi0.50Na0.50TiO3 (BNT) based solid solutions. The pseudo-binary (1 − x)Bi0.50Na0.50TiO3–xBa1 − yCayTiO3 system has been proposed for high temperature capacitors and not yet fully explored as piezoelectric material. In this work, the solid solution with x = 0.06 and y = 0.10 was obtained by two different synthesis routes: solid state and Pechini, aiming at using reduced temperatures, both in synthesis (<800 °C) and sintering (<1150 °C), while maintaining appropriated piezoelectric performance. Crystal structure, ceramic grain size, and morphology depend on the synthesis route and were analyzed by X-ray diffraction, together with scanning and transmission electron microscopy. The effects of processing and ceramic microstructure on the structural, dielectric, ferroelectric, and piezoelectric properties were discussed in terms of a shift of the Morphotropic Phase Boundary, chemically induced by the synthesis route. PMID:28773096

  19. Application of RAD-BCG calculator to Hanford's 300 area shoreline characterization dataset

    Energy Technology Data Exchange (ETDEWEB)

    Antonio, Ernest J.; Poston, Ted M.; Tiller, Brett L.; Patton, Gene W.

    2003-07-01

    Abstract. In 2001, a multi-agency study was conducted to characterize potential environmental effects from radiological and chemical contaminants on the near-shore environment of the Columbia River at the 300 Area of the U.S. Department of Energy’s Hanford Site. Historically, the 300 Area was the location of nuclear fuel fabrication and was the main location for research and development activities from the 1940s until the late 1980s. During past waste handling practices uranium, copper, and other heavy metals were routed to liquid waste streams and ponds near the Columbia River shoreline. The Washington State Department of Health and the Pacific Northwest National Laboratory’s Surface Environmental Surveillance Project sampled various environmental components including river water, riverbank spring water, sediment, fishes, crustaceans, bivalve mollusks, aquatic insects, riparian vegetation, small mammals, and terrestrial invertebrates for analyses of radiological and chemical constituents. The radiological analysis results for water and sediment were used as initial input into the RAD-BCG Calculator. The RAD-BCG Calculator, a computer program that uses an Excel® spreadsheet and Visual Basic® software, showed that maximum radionuclide concentrations measured in water and sediment were lower than the initial screening criteria for concentrations to produce dose rates at existing or proposed limits. Radionuclide concentrations measured in biota samples were used to calculate site-specific bioaccumulation coefficients (Biv) to test the utility of the RAD-BCG-Calculator’s site-specific screening phase. To further evaluate site-specific effects, the default Relative Biological Effect (RBE) for internal alpha particle emissions was reduced by half and the program’s kinetic/allometric calculation approach was initiated. The subsequent calculations showed the initial RAD-BCG Calculator results to be conservative, which is appropriate for screening purposes.

  20. Biocidal and Sporicidal Efficacy of Pathoster® 0.35% and Pathoster® 0.50% Against Bacterial Agents in Potential Bioterrorism Use

    Science.gov (United States)

    Candeliere, Antonio; Donatiello, Adelia; Pagano, Stefania; Iatarola, Michela; Tolve, Francesco; Antonino, Leonardo; Fasanella, Antonio

    2016-01-01

    The use of products that can neutralize or significantly reduce the microbial load and that are not harmful to human health and the environment represents a milestone in the fight against the spread of infectious diseases. Peracetic acid, besides being an excellent sterilizing and sporicidal agent, is harmless to humans and the environment when it is used in a common dosage. However, the high costs and loss of efficacy of the product very quickly after its reconstitution limit its use. We evaluated the efficacy and stability of 2 commercial products, based on stabilized peracetic acid (Pathoster® 0.35% and Pathoster® 0.50%) used against spores of Bacillus anthracis and spores of Bacillus cereus and vegetative forms of Yersinia pestis, Burkholderia mallei, Burkholderia pseudomallei, Francisella tularensis, Brucella abortus, and Brucella melitensis. The efficacy tests were based on the direct contact of the products with a standard suspension of the bacteria. The stability of the products was defined as the period of time during which the biocidal and sporicidal properties remained unchanged. The limit of effectiveness was the period after which the product was unable to exert a complete sterilization after a contact of 5 minutes with at least 1 of the 8 bacteria used in this work. Both formulations showed good efficacy against the microorganisms used in the study, confirming the utility of peracetic acid as a sterilizing product. After the reconstitution, Pathoster® 0.35% was stable until 16±1 days, while Pathoster® 0.50% was stable until 24±1 days. The formulations used in this study showed good performance and a significant stability of peracetic acid. PMID:27482880

  1. Extreme Temperature, Rad-Hard Power Management ASIC, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Ridgetop Group will design a rad-hard Application Specific Integrated Circuit (ASIC) for spacecraft power management that is functional over a temperature range of...

  2. RadNet-Air Near Real Time Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — RadNet-Air is a national network of air monitoring stations that regularly collect air samples for near real time analysis of radioactivity. The data is transmitted...

  3. RadNet (Environmental Radiation Ambient Monitoring System)

    Data.gov (United States)

    U.S. Environmental Protection Agency — RadNet, formerly Environmental Radiation Ambient Monitoring System (ERAMS), is a national network of monitoring stations that regularly collect air, precipitation,...

  4. RadNet Real-Time Monitoring Spectrometry Data Inventory

    Data.gov (United States)

    U.S. Environmental Protection Agency — The RadNet Real-Time Monitoring Spectrometry Data Inventory contains measured data used to identify and measure specific radioactive materials in the atmosphere at...

  5. Rad-hard embedded computers for nuclear robotics

    International Nuclear Information System (INIS)

    Giraud, A.; Joffre, F.; Marceau, M.; Robiolle, M.; Brunet, J.P.; Mijuin, D.

    1993-01-01

    For requirements of nuclear industries, it is necessary to use robots with embedded rad hard electronics and high level safety. The computer developed for french research program SYROCO is presented in this paper. (authors). 8 refs., 5 figs

  6. Structured reporting platform improves CAD-RADS assessment.

    Science.gov (United States)

    Szilveszter, Bálint; Kolossváry, Márton; Karády, Júlia; Jermendy, Ádám L; Károlyi, Mihály; Panajotu, Alexisz; Bagyura, Zsolt; Vecsey-Nagy, Milán; Cury, Ricardo C; Leipsic, Jonathon A; Merkely, Béla; Maurovich-Horvat, Pál

    2017-11-01

    Structured reporting in cardiac imaging is strongly encouraged to improve quality through consistency. The Coronary Artery Disease - Reporting and Data System (CAD-RADS) was recently introduced to facilitate interdisciplinary communication of coronary CT angiography (CTA) results. We aimed to assess the agreement between manual and automated CAD-RADS classification using a structured reporting platform. Five readers prospectively interpreted 500 coronary CT angiographies using a structured reporting platform that automatically calculates the CAD-RADS score based on stenosis and plaque parameters manually entered by the reader. In addition, all readers manually assessed CAD-RADS blinded to the automatically derived results, which was used as the reference standard. We evaluated factors influencing reader performance including CAD-RADS training, clinical load, time of the day and level of expertise. Total agreement between manual and automated classification was 80.2%. Agreement in stenosis categories was 86.7%, whereas the agreement in modifiers was 95.8% for "N", 96.8% for "S", 95.6% for "V" and 99.4% for "G". Agreement for V improved after CAD-RADS training (p = 0.047). Time of the day and clinical load did not influence reader performance (p > 0.05 both). Less experienced readers had a higher total agreement as compared to more experienced readers (87.0% vs 78.0%, respectively; p = 0.011). Even though automated CAD-RADS classification uses data filled in by the readers, it outperforms manual classification by preventing human errors. Structured reporting platforms with automated calculation of the CAD-RADS score might improve data quality and support standardization of clinical decision making. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  7. A uniform system for mammographic reporting BI-RADS

    International Nuclear Information System (INIS)

    Masroor, I.; Ahmad, M. N.; Sheikh, M. Y.

    2001-01-01

    Breast image reporting and data system (BI-RADS) is a new system of categorizing and reporting mammographs and mammographic findings recommended by American College of Radiology. The importance of BI-RADS and final assessment categories are discussed. The purpose is to introduce the above-mentioned mammographic reporting system so that it becomes a standard terminology among the medical personnel, involved in the diagnosis and management of breast diseases. (author)

  8. Extracting BI-RADS Features from Portuguese Clinical Texts.

    Science.gov (United States)

    Nassif, Houssam; Cunha, Filipe; Moreira, Inês C; Cruz-Correia, Ricardo; Sousa, Eliana; Page, David; Burnside, Elizabeth; Dutra, Inês

    2012-01-01

    In this work we build the first BI-RADS parser for Portuguese free texts, modeled after existing approaches to extract BI-RADS features from English medical records. Our concept finder uses a semantic grammar based on the BIRADS lexicon and on iterative transferred expert knowledge. We compare the performance of our algorithm to manual annotation by a specialist in mammography. Our results show that our parser's performance is comparable to the manual method.

  9. Human RAD50 makes a functional DNA-binding complex.

    Science.gov (United States)

    Kinoshita, Eri; van Rossum-Fikkert, Sari; Sanchez, Humberto; Kertokalio, Aryandi; Wyman, Claire

    2015-06-01

    The MRE11-RAD50-NBS1 (MRN) complex has several distinct functions in DNA repair including important roles in both non-homologous end-joining (NHEJ) and homologous recombination (HR). The biochemical activities of MR(N) have been well characterized implying specific functional roles for the components. The arrangement of proteins in the complex implies interdependence of their biochemical activities making it difficult to separate specific functions. We obtained purified human RAD50 and observed that it binds ATP, undergoes ATP-dependent conformational changes as well as having ATPase activity. Scanning force microscopy analysis clearly showed that RAD50 binds DNA although not as oligomers. RAD50 alone was not functional in tethering DNA molecules. ATP increased formation of RAD50 multimers which were however globular lacking extended coiled coils, in contrast to the MR complex where ATP induced oligomers have obvious coiled coils protruding from a central domain. These results suggest that MRE11 is important in maintaining the structural arrangement of RAD50 in the protein complex and perhaps has a role in reinforcing proper alignment of the coiled coils in the ATP-bound state. Copyright © 2015 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  10. RAD51 interconnects between DNA replication, DNA repair and immunity.

    Science.gov (United States)

    Bhattacharya, Souparno; Srinivasan, Kalayarasan; Abdisalaam, Salim; Su, Fengtao; Raj, Prithvi; Dozmorov, Igor; Mishra, Ritu; Wakeland, Edward K; Ghose, Subroto; Mukherjee, Shibani; Asaithamby, Aroumougame

    2017-05-05

    RAD51, a multifunctional protein, plays a central role in DNA replication and homologous recombination repair, and is known to be involved in cancer development. We identified a novel role for RAD51 in innate immune response signaling. Defects in RAD51 lead to the accumulation of self-DNA in the cytoplasm, triggering a STING-mediated innate immune response after replication stress and DNA damage. In the absence of RAD51, the unprotected newly replicated genome is degraded by the exonuclease activity of MRE11, and the fragmented nascent DNA accumulates in the cytosol, initiating an innate immune response. Our data suggest that in addition to playing roles in homologous recombination-mediated DNA double-strand break repair and replication fork processing, RAD51 is also implicated in the suppression of innate immunity. Thus, our study reveals a previously uncharacterized role of RAD51 in initiating immune signaling, placing it at the hub of new interconnections between DNA replication, DNA repair, and immunity. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  11. Environmental radon with RAD7 detector

    International Nuclear Information System (INIS)

    Lopez M, A.; Balcazar, M.; Fernandez G, I. M.; Capote F, E.

    2016-09-01

    Experimental results of the radon detection with the equipment RAD7 are presented. The use of a solid state detector placed in a semi-spherical chamber with an electric field allows a high sensitivity of 0.4 cpm/P Ci/l. Radon detection is achieved by the spectroscopy of its decay products. In accordance with a table of errors for various ranges of counts and radon concentrations, reported by the manufacturer, an equation was obtained that allows establishing operation criteria of the equipment. For radon detection at ambient concentrations as low as 30 Bq m -3 , is shown that short counts of 10 minutes are good enough to make decisions on radiation protection matter. In places where concentrations are close to 200 Bq m -3 , counting intervals of the order of 0.5 hours will have an acceptable counting error of the order of 20%. The determination of radon in soil was, according to the expected, on the order of 10 kBq m -3 , and was found that even with the recommended counting times of 5 minutes, there is a risk of increased humidity inside the detector above 20% Rh, with associated reduction of detection efficiency, if the desiccant is not used properly. The equipment was subjected to a radon exposure in air of 13, 373 Bq m -3 ± 3.7%, contained within a controlled chamber, with a variation in temperature of (19-21) degrees Celsius and in the relative humidity of (5-7) %, the good stability of the chamber allows to propose calibration processes of these equipment s by assessing the concentration by means of a Ge (Hp) detector. (Author)

  12. Three additional genes involved in pyrimidine dimer removal in Saccharomyces cerevisiae: RAD7, RAD14, and MMS19

    Energy Technology Data Exchange (ETDEWEB)

    Prakash, L; Prakash, S

    1979-01-01

    The ability to remove ultraviolet (uv)-induced pyrimidine dimers from the nuclear DNA of yeast was examined in two radiation-sensitive (rad) mutants and one methyl methanesulfonate-sensitive (mms) mutant of the yeast Saccharomyces cerevisiae. The susceptibility of DNA from irradiated cells to nicking by an endonuclease activity prepared from crude extracts of Micrococcus luteus was used to measure the presence of dimers in DNA. The rad7, rad14, and mms19 mutants were found to be defective in their ability to remove uv-induced dimers from nuclear DNA. All three mutants belong to the same episatic group as the other mutants involved in excision-repair. All three mutants show enhanced uv-induced mutations. The rad 14 mutant also shows epistatic interactions with genes in the other two uv repair pathways.

  13. Molecular anatomy of the recombination mediator function of Saccharomyces cerevisiae Rad52

    DEFF Research Database (Denmark)

    Seong, C.; Sehorn, M.G.; Plate, Iben

    2008-01-01

    A helical filament of Rad51 on single-strand DNA (ssDNA), called the presynaptic filament, catalyzes DNA joint formation during homologous recombination. Rad52 facilitates presynaptic filament assembly, and this recombination mediator activity is thought to rely on the interactions of Rad52...... with Rad51, the ssDNA-binding protein RPA, and ssDNA. The N-terminal region of Rad52, which has DNA binding activity and an oligomeric structure, is thought to be crucial for mediator activity and recombination. Unexpectedly, we find that the C-terminal region of Rad52 also harbors a DNA binding function....... Importantly, the Rad52 C-terminal portion alone can promote Rad51 presynaptic filament assembly. The middle portion of Rad52 associates with DNA-bound RPA and contributes to the recombination mediator activity. Accordingly, expression of a protein species that harbors the middle and C-terminal regions of Rad...

  14. 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

  15. Cellular Dynamics of Rad51 and Rad54 in Response to Postreplicative Stress and DNA Damage in HeLa Cells.

    Science.gov (United States)

    Choi, Eui-Hwan; Yoon, Seobin; Hahn, Yoonsoo; Kim, Keun P

    2017-02-01

    Homologous recombination (HR) is necessary for maintenance of genomic integrity and prevention of various mutations in tumor suppressor genes and proto-oncogenes. Rad51 and Rad54 are key HR factors that cope with replication stress and DNA breaks in eukaryotes. Rad51 binds to single-stranded DNA (ssDNA) to form the presynaptic filament that promotes a homology search and DNA strand exchange, and Rad54 stimulates the strand-pairing function of Rad51. Here, we studied the molecular dynamics of Rad51 and Rad54 during the cell cycle of HeLa cells. These cells constitutively express Rad51 and Rad54 throughout the entire cell cycle, and the formation of foci immediately increased in response to various types of DNA damage and replication stress, except for caffeine, which suppressed the Rad51-dependent HR pathway. Depletion of Rad51 caused severe defects in response to postreplicative stress. Accordingly, HeLa cells were arrested at the G2-M transition although a small amount of Rad51 was steadily maintained in HeLa cells. Our results suggest that cell cycle progression and proliferation of HeLa cells can be tightly controlled by the abundance of HR proteins, which are essential for the rapid response to postreplicative stress and DNA damage stress.

  16. Determination of radon concentration in water using RAD7 with RAD H2O accessories

    International Nuclear Information System (INIS)

    Malik, M. F. I.; Rabaiee, N. A.; Jaafar, M. S.

    2015-01-01

    In the last decade, the radon issue has become one of the major problems of radiation protection. Radon exposure occurs when using water for showering, washing dishes, cooking and drinking water. RAD7 and Rad H20 accessories were used in order to measure radon concentration in water sample. In this study, four types of water were concerns which are reverse osmosis (drinking water), mineral water, tap water and well water. Reverse osmosis (drinking water) and mineral water were bought from the nearest supermarket while tap water and well water were taken from selected areas of Pulau Pinang and Kedah. Total 20 samples were taken with 5 samples for each type of water. The measured radon concentration ranged from 2.9±2.9 to 79.5±17 pCi/L, 2.9±2.9 to 67.8±16 pCi/L, 15.97±7 to 144.25±24 pCi/L and 374.89±37 to 6409.03±130 pCi/L in reverse osmosis (drinking water), mineral water, tap water and well water. Well water has the highest radon compared to others. It was due to their geological element such as granite. Results for all types of water are presented and compared with maximum contamination limit (MCL) recommended by United State Environmental Protection Agency (USEPA) which is 300pCi/L. Reverse osmosis water, mineral water and tap water were fall below MCL. However, well water was exceeded maximum level that was recommended. Thus, these findings were suggested that an action should be taken to reduce radon concentration level in well water as well as reduce a health risk towards the public

  17. The C-terminal region of Rad52 is essential for Rad52 nuclear and nucleolar localization, and accumulation at DNA damage sites immediately after irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Koike, Manabu, E-mail: m_koike@nirs.go.jp [DNA Repair Gene Res., National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Yutoku, Yasutomo [DNA Repair Gene Res., National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Graduate School of Science, Chiba University, Yayoicho, Inage-ku, Chiba 263-8522 (Japan); Koike, Aki [DNA Repair Gene Res., National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan)

    2013-05-31

    Highlights: •Rad52 might play a key role in the repair of DSB immediately after irradiation. •EYFP-Rad52 accumulates rapidly at DSB sites and colocalizes with Ku80. •Accumulation of Rad52 at DSB sites is independent of the core NHEJ factors. •Localization and recruitment of Rad52 to DSB sites are dependent on the Rad52 CTR. •Basic amino acids in Rad52 CTR are highly conserved among vertebrate species. -- Abstract: Rad52 plays essential roles in homologous recombination (HR) and repair of DNA double-strand breaks (DSBs) in Saccharomyces cerevisiae. However, in vertebrates, knockouts of the Rad52 gene show no hypersensitivity to agents that induce DSBs. Rad52 localizes in the nucleus and forms foci at a late stage following irradiation. Ku70 and Ku80, which play an essential role in nonhomologous DNA-end-joining (NHEJ), are essential for the accumulation of other core NHEJ factors, e.g., XRCC4, and a HR-related factor, e.g., BRCA1. Here, we show that the subcellular localization of EYFP-Rad52(1–418) changes dynamically during the cell cycle. In addition, EYFP-Rad52(1–418) accumulates rapidly at microirradiated sites and colocalizes with the DSB sensor protein Ku80. Moreover, the accumulation of EYFP-Rad52(1–418) at DSB sites is independent of the core NHEJ factors, i.e., Ku80 and XRCC4. Furthermore, we observed that EYFP-Rad52(1–418) localizes in nucleoli in CHO-K1 cells and XRCC4-deficient cells, but not in Ku80-deficient cells. We also found that Rad52 nuclear localization, nucleolar localization, and accumulation at DSB sites are dependent on eight amino acids (411–418) at the end of the C-terminal region of Rad52 (Rad52 CTR). Furthermore, basic amino acids on Rad52 CTR are highly conserved among mammalian, avian, and fish homologues, suggesting that Rad52 CTR is important for the regulation and function of Rad52 in vertebrates. These findings also suggest that the mechanism underlying the regulation of subcellular localization of Rad52 is

  18. RAD18 mediates resistance to ionizing radiation in human glioma cells

    International Nuclear Information System (INIS)

    Xie, Chen; Wang, Hongwei; Cheng, Hongbin; Li, Jianhua; Wang, Zhi; Yue, Wu

    2014-01-01

    Highlights: • RAD18 is an important mediator of the IR-induced resistance in glioma cell lines. • RAD18 overexpression confers resistance to IR-mediated apoptosis. • The elevated expression of RAD18 is associated with recurrent GBM who underwent IR therapy. - Abstract: Radioresistance remains a major challenge in the treatment of glioblastoma multiforme (GBM). RAD18 a central regulator of translesion DNA synthesis (TLS), has been shown to play an important role in regulating genomic stability and DNA damage response. In the present study, we investigate the relationship between RAD18 and resistance to ionizing radiation (IR) and examined the expression levels of RAD18 in primary and recurrent GBM specimens. Our results showed that RAD18 is an important mediator of the IR-induced resistance in GBM. The expression level of RAD18 in glioma cells correlates with their resistance to IR. Ectopic expression of RAD18 in RAD18-low A172 glioma cells confers significant resistance to IR treatment. Conversely, depletion of endogenous RAD18 in RAD18-high glioma cells sensitized these cells to IR treatment. Moreover, RAD18 overexpression confers resistance to IR-mediated apoptosis in RAD18-low A172 glioma cells, whereas cells deficient in RAD18 exhibit increased apoptosis induced by IR. Furthermore, knockdown of RAD18 in RAD18-high glioma cells disrupts HR-mediated repair, resulting in increased accumulation of DSB. In addition, clinical data indicated that RAD18 was significantly higher in recurrent GBM samples that were exposed to IR compared with the corresponding primary GBM samples. Collectively, our findings reveal that RAD18 may serve as a key mediator of the IR response and may function as a potential target for circumventing IR resistance in human GBM

  19. A novel interation of nucleolin with Rad51

    International Nuclear Information System (INIS)

    De, Ananya; Donahue, Sarah L.; Tabah, Azah; Castro, Nancy E.; Mraz, Naomi; Cruise, Jennifer L.; Campbell, Colin

    2006-01-01

    Nucleolin associates with various DNA repair, recombination, and replication proteins, and possesses DNA helicase, strand annealing, and strand pairing activities. Examination of nuclear protein extracts from human somatic cells revealed that nucleolin and Rad51 co-immunoprecipitate. Furthermore, purified recombinant Rad51 associates with in vitro transcribed and translated nucleolin. Electroporation-mediated introduction of anti-nucleolin antibody resulted in a 10- to 20-fold reduction in intra-plasmid homologous recombination activity in human fibrosarcoma cells. Additionally, introduction of anti-nucleolin antibody sensitized cells to death induced by the topoisomerase II inhibitor, amsacrine. Introduction of anti-Rad51 antibody also reduced intra-plasmid homologous recombination activity and induced hypersensitivity to amsacrine-induced cell death. Co-introduction of anti-nucleolin and anti-Rad51 antibodies did not produce additive effects on homologous recombination or on cellular sensitivity to amsacrine. The association of the two proteins raises the intriguing possibility that nucleolin binding to Rad51 may function to regulate homologous recombinational repair of chromosomal DNA

  20. Interdependence of the rad50 hook and globular domain functions.

    Science.gov (United States)

    Hohl, Marcel; Kochańczyk, Tomasz; Tous, Cristina; Aguilera, Andrés; Krężel, Artur; Petrini, John H J

    2015-02-05

    Rad50 contains a conserved Zn(2+) coordination domain (the Rad50 hook) that functions as a homodimerization interface. Hook ablation phenocopies Rad50 deficiency in all respects. Here, we focused on rad50 mutations flanking the Zn(2+)-coordinating hook cysteines. These mutants impaired hook-mediated dimerization, but recombination between sister chromatids was largely unaffected. This may reflect that cohesin-mediated sister chromatid interactions are sufficient for double-strand break repair. However, Mre11 complex functions specified by the globular domain, including Tel1 (ATM) activation, nonhomologous end joining, and DNA double-strand break end resection were affected, suggesting that dimerization exerts a broad influence on Mre11 complex function. These phenotypes were suppressed by mutations within the coiled-coil and globular ATPase domains, suggesting a model in which conformational changes in the hook and globular domains are transmitted via the extended coils of Rad50. We propose that transmission of spatial information in this manner underlies the regulation of Mre11 complex functions. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. BI-RADS: Use in the French radiologic community

    International Nuclear Information System (INIS)

    Stines, Joseph

    2007-01-01

    In the United States, BI-RADS TM (Breast Imaging Reporting and Data System) has been set up as a quality assurance system for better communication between professionals and for the follow-up of breast screening programs. It has become a reference in the field of mammographic imaging and has been adopted by several countries throughout the world. It has been translated in French. The aim of this article is to discuss the difficulties in using it in the French radiologic communities. There are few problems with vocabulary excepted for microcalcifications. BI-RADS TM includes a guidance chapter giving some recommendations for using properly the lexicon. Classification of normal breast remains of concern, as it is difficult to evaluate precisely the content of fat and as the final image is also dependant of technical factors. The main difficulties are related to final classification in BI-RADS TM categories as the lexicon does not explicit which mammographic features should be included in the categories from three to five. In France, a table concerning the classification of mammographic abnormalities has been established by the HAS (former ANAES) which represents the highest scientific health authority in France. There are no major problems for using the BI-RADS TM for US and MRI. BI-RADS TM is suitable for different categories of women and for male and training has an important impact on acceptance and proper use of the lexicon

  2. Simulation of aerosol radiative properties with the ORISAM-RAD model during a pollution event (ESCOMPTE 2001)

    Science.gov (United States)

    Mallet, M.; Pont, V.; Liousse, C.; Roger, J. C.; Dubuisson, P.

    The aim of this study is to present the organic and inorganic spectral aerosol module-radiative (ORISAM-RAD) module, allowing the 3D distribution of aerosol radiative properties (aerosol optical depth, single scattering albedo and asymmetry parameter) from the ORISAM module. In this work, we test ORISAM-RAD for one selected day (24th June) during the ESCOMPTE (expérience sur site pour contraindre les modèles de pollution atmosphérique et de transport d'emissions) experiment for an urban/industrial aerosol type. The particle radiative properties obtained from in situ and AERONET observations are used to validate our simulations. In a first time, simulations obtained from ORISAM-RAD indicate high aerosol optical depth (AOD)˜0.50-0.70±0.02 (at 440 nm) in the aerosol pollution plume, slightly lower (˜10-20%) than AERONET retrievals. In a second time, simulations of the single scattering albedo ( ωo) have been found to well reproduce the high spatial heterogeneities observed over this domain. Concerning the asymmetry parameter ( g), ORISAM-RAD simulations reveal quite uniform values over the whole ESCOMPTE domain, comprised between 0.61±0.01 and 0.65±0.01 (at 440 nm), in excellent agreement with ground based in situ measurements and AERONET retrievals. Finally, the outputs of ORISAM-RAD have been used in a radiative transfer model in order to simulate the diurnal direct radiative forcing at different locations (urban, industrial and rural). We show that anthropogenic aerosols strongly decrease surface solar radiation, with diurnal mean surface forcings comprised between -29.0±2.9 and -38.6±3.9 W m -2, depending on the sites. This decrease is due to the reflection of solar radiations back to space (-7.3±0.8<Δ FTOA<-12.3±1.2 W m -2) and to its absorption into the aerosol layer (21.1±2.1<Δ FATM<26.3±2.6 W m -2). These values are found to be consistent with those measured at local scale.

  3. Effects of Sr2+ doping on the electrical properties of (Bi0.5Na0.50.94Ba0.06TiO3 ceramics

    Directory of Open Access Journals (Sweden)

    Amrita Singh

    2015-03-01

    Full Text Available The influence of SrTiO3 addition on the microstructure and various electrical properties of (Bi0.5Na0.50.94Ba0.06TiO3 (BNTBT6 ceramics, fabricated by a conventional high temperature solid state reaction, was investigated. Analysis of X-ray diffraction patterns revealed the formation of phase pure materials with tetragonal unit cell structure, tetragonality parameter c/a in the interval from 0.9940 to 1.0063 and crystallite sizes ranging from 33–76 nm for addition of 0.2 to 1 wt.% of SrTiO3. SEM studies indicated that Sr2+ doping led to decrease in grain size and non-homogeneity of grain distribution for higher SrTiO3 amount (>0.6 wt.%. Complex impedance, modulus, and conductivity studies indicated the presence of grains and grain boundary contribution, non-Debye type of relaxation and NTCR behaviour of the test ceramic samples. Temperature dependent real part of complex permittivity showed peaks at 475 °C and the dielectric loss tangent showed peaks corresponding to 125 °C and 475 °C for almost all compositions. AC activation energies, computed using Arrhenius relation in the temperature range of 325–500 °C for the BNTBT6 ceramic compositions having SrTiO3 concentration from 0.2 to 1.0 wt.%, were seen to have maximal values at the lowest measurement frequency. Amongst the different chosen doped BNTBT6 ceramic compositions, the composition having 0.6 wt.% of SrTiO3 showed the best ferroelectric and piezoelectric response with maximum value of Pr (8.24 µC/cm2, minimum value of Ec (5.73 kV/mm and maximum d33 value (∼46 pC/N.

  4. Dose estimation from residual and fallout radioactivity, 1

    International Nuclear Information System (INIS)

    Takeshita, Kenji

    1975-01-01

    External dose rates and cumulative doses for early entrants from areal surveys and simulated experiments are reviewed. The average cumulative doses to infinity at the hypocenters were 101 rad in Hiroshima and 32 rad in Nagasaki, with a variation of about 60 percent. Radioactive fallout areas nearly matched the ''black rain'' areas in Nagasaki and in Hiroshima. Radioactivity in the fallout areas was affected by radioactive decay and by the leaching and dissipation by rains. Considering these factors, the cumulative dose to infinity in the fallout area of Hiroshima was estimated to be 13 rad, excluding internal radiation doses from inhaled and ingested radionuclides. Attempts to estimate radiation dose from internally deposited radionuclides are also described. (auth.)

  5. Molecular Basis for Enhancement of the Meiotic DMCI Recombinase by RAD51AP1

    Energy Technology Data Exchange (ETDEWEB)

    Dray, Eloise; Dunlop, Myun Hwa; Kauppi, Liisa; San Filippo, Joseph San; Wiese, Claudia; Tsai, Miaw-Sheue; Begovic, Sead; Schild, David; Jasin, Maria; Keeney, Scott; Sung, Patrick

    2010-11-05

    Homologous recombination is needed for meiotic chromosome segregation, genome maintenance, and tumor suppression. RAD51AP1 (RAD51 Associated Protein 1) has been shown to interact with and enhance the recombinase activity of RAD51. Accordingly, genetic ablation of RAD51AP1 leads to enhanced sensitivity to and also chromosome aberrations upon DNA damage, demonstrating a role for RAD51AP1 in mitotic homologous recombination. Here we show physical association of RAD51AP1 with the meiosis-specific recombinase DMC1 and a stimulatory effect of RAD51AP1 on the DMC1-mediated D-loop reaction. Mechanistic studies have revealed that RAD51AP1 enhances the ability of the DMC1 presynaptic filament to capture the duplex DNA partner and to assemble the synaptic complex, in which the recombining DNA strands are homologously aligned. We also provide evidence that functional co-operation is dependent on complex formation between DMC1 and RAD51AP1, and that distinct epitopes in RAD51AP1 mediate interactions with RAD51 and DMC1. Finally, we show that RAD51AP1 is expressed in mouse testes, and that RAD51AP1 foci co-localize with a subset of DMC1 foci in spermatocytes. These results suggest that RAD51AP1 also serves an important role in meiotic homologous recombination.

  6. RadCon: Parameter report focusing on Tropical and Subtropical environments in Australia

    International Nuclear Information System (INIS)

    Domel, R.U.; Crawford, J; Harris, F.; Twining, J.

    2000-09-01

    Models to simulate the transfer of radionuclides through air, water and terrestrial ecosystems have been developed and used regularly over the last 20 years. RadCon was developed as a simple model to assess the radiological consequences, as dose, to humans of short-term depositions of radionuclides. Internal exposure via inhalation and ingestion are included in this model as well as external exposure from the passing cloud (cloud shine) and from radioactivity deposited on the ground (ground shine).Initially, the RadCon model will deal with the Australian and South East Asian region but flexibility has been incorporated into the design to allow application in other regions. In a manner similar to a geographic information system, the display of input and output data allows quick access to the results, both numerically and graphically. Coloured concentration gradients, stepping through time, are superimposed on the area of interest to present atmospheric and ground concentrations of the radionuclides and, after the calculations, human dose. The model has portability across computer platforms.This report summarises the parameters and some of the transfer factors underlying the calculations. While the focus was on the tropical and subtropical regions in Australia, for many parameters the values may only have been available for temperate regions, in which case this has been used as the default value. The parameter flexibility is a major aspect of this model and a report to describe the editor has been written (Crawford and Domel, ANSTO/M-129). The aim of this document is to chronologically expand on the formulae and parameter tables presented in the Technical Guide (Crawford et al., ANSTO/E-744, May 2000). The two documents should be read together with the Technical Guide presenting the mathematical computations and this report presenting some of the input values used to calculate the end-point results from the computations. A User Guide to assist in the implementation

  7. RadCat 3.0 user guide.

    Energy Technology Data Exchange (ETDEWEB)

    Hinojosa, Daniel; Penisten, Janelle J.; Dennis, Matthew L.; Osborn, Douglas M.; Weiner, Ruth F.; Heames, Terence John; Marincel, Michelle K.

    2009-05-01

    RADTRAN is an internationally accepted program and code for calculating the risks of transporting radioactive materials. The first versions of the program, RADTRAN I and II, were developed for NUREG-0170 (USNRC, 1977), the first environmental statement on transportation of radioactive materials. RADTRAN and its associated software have undergone a number of improvements and advances consistent with improvements in both available data and computer technology. The version of RADTRAN currently bundled with RadCat is RADTRAN 6.0. This document provides a detailed discussion and a guide for the use of the RadCat 3.0 Graphical User Interface input file generator for the RADTRAN code. RadCat 3.0 integrates the newest analysis capabilities of RADTRAN 6.0 which includes an economic model, updated loss-of-lead shielding model, and unit conversion. As of this writing, the RADTRAN version in use is RADTRAN 6.0.

  8. Effect of single-dose radiation on cell survival and growth hormone secretion by rat anterior pituitary cells

    International Nuclear Information System (INIS)

    Hochberg, Z.; Kuten, A.; Hertz, P.; Tatcher, M.; Kedar, A.; Benderly, A.

    1983-01-01

    Cranial irradiation has been shown to impair growth hormone secretion in children. In this study a cell culture of dispersed rat anterior pituitary cells was exposed to single doses of radiation in the range of 100 to 1500 rad. Survival curves were obtained for the different anterior pituitary cell lines, and growth hormone secretion was measured in the tissue culture medium. Both survival and growth hormone secretion curves showed an initial shoulder in the range of 0 to 300 rad, followed by a decline between 300 to 750 rad. It is concluded that growth hormone secreting acidophilic pituicytes are sensitive to radiation at single doses greater than 300 rad

  9. Option study of an orthogonal X-ray radiography axis for pRad at LANSCE area C, Los Alamos

    International Nuclear Information System (INIS)

    Oliver, Bryan Velten; Johnson, David L.; Leckbee, Joshua J.; Jones, Peter

    2010-01-01

    We report on an option study of two potential x-ray systems for orthogonal radiography at Area C in the LANSCE facility at Los Alamos National Laboratory. The systems assessed are expected to be near equivalent systems to the presently existing Cygnus capability at the Nevada Test Site. Nominal dose and radiographic resolution of 4 rad (measured at one meter) and 1 mm spot are desired. Both a system study and qualitative design are presented as well as estimated cost and schedule. Each x-ray system analyzed is designed to drive a rod-pinch electron beam diode capable of producing the nominal dose and spot.

  10. FANCI-FANCD2 stabilizes the RAD51-DNA complex by binding RAD51 and protects the 5′-DNA end

    Science.gov (United States)

    Sato, Koichi; Shimomuki, Mayo; Katsuki, Yoko; Takahashi, Daisuke; Kobayashi, Wataru; Ishiai, Masamichi; Miyoshi, Hiroyuki; Takata, Minoru; Kurumizaka, Hitoshi

    2016-01-01

    The FANCI-FANCD2 (I-D) complex is considered to work with RAD51 to protect the damaged DNA in the stalled replication fork. However, the means by which this DNA protection is accomplished have remained elusive. In the present study, we found that the I-D complex directly binds to RAD51, and stabilizes the RAD51-DNA filament. Unexpectedly, the DNA binding activity of FANCI, but not FANCD2, is explicitly required for the I-D complex-mediated RAD51-DNA filament stabilization. The RAD51 filament stabilized by the I-D complex actually protects the DNA end from nucleolytic degradation by an FA-associated nuclease, FAN1. This DNA end protection is not observed with the RAD51 mutant from FANCR patient cells. These results clearly answer the currently enigmatic question of how RAD51 functions with the I-D complex to prevent genomic instability at the stalled replication fork. PMID:27694619

  11. Characterization of iminothiosulfine-type ions [HNCS 2] rad +/ rad - and their neutral counterparts by mass spectrometry and computational chemistry

    Science.gov (United States)

    Vivekananda, S.; Raghunath, P.; Bhanuprakash, K.; Srinivas, R.; Trikoupis, Moschoula A.; Terlouw, Johan K.

    2000-12-01

    Electron ionization of rhodanine yields iminothiosulfine ions H- N C- S- Srad + , 1brad + , which readily communicate with the higher energy cyclic isomer H- N CS2rad + , 1arad + . CBS-QB3 and G AUSSIAN-2 model chemistries predict that one electron reduction reverses the stability order but that the (singlet) neutrals remain connected via a negligible energy barrier. Neutralization-reionization (NR) experiments demonstrate that singlet 1a and its heterocumulene isomer 1b are stable species in the gas-phase. However, the co-generated triplet species readily dissociate into 3S2rad + + HNC. Confirmatory experimental evidence comes from charge reversal (CR) and NR experiments on the cyclic anion H- N CS2rad - , 1arad - .

  12. Comparable effects of 1800- and 2400-rad (18- and 24-Gy) cranial irradiation on height and weight in children treated for acute lymphocytic leukemia

    International Nuclear Information System (INIS)

    Starceski, P.J.; Lee, P.A.; Blatt, J.; Finegold, D.; Brown, D.

    1987-01-01

    To examine the effects of low-dose cranial irradiation on growth and to determine if one can predict patients in whom growth will be most affected, we studied 47 children with acute lymphocytic leukemia who had been treated with 2400 rad (24 Gy), 1800 rad (18 Gy), or no whole-brain irradiation. Serial measurements of height, weight, and weight for height were obtained by retrospective chart review. The effects of 1800 rad (18 Gy) and 2400 rad (24 Gy) treatment were indistinguishable. Height percentiles among irradiated patients decreased by a mean of 12% six months after diagnosis, and growth generally did not catch up. Moreover, although 33 irradiated patients maintained heights within the normal range, In 11 patients (33%) a dramatic falloff occurred such that by three years following diagnosis their height for age was more than 30 percentiles below the original value. These patients were all identifiable at six months since their height percentiles had already decreased by more than 15%. Although weight percentiles did not change following irradiation, the weight-for-height ratio increased and patients were relatively stockier three years after therapy than they had been at diagnosis. In patients who had received chemotherapy alone, the weight-for-height ratio also increased, but this appeared to be due to a disproportionate increase in weight. Longer follow-up and evaluation of larger cohorts of patients treated with 1800 rad (18 Gy) will be needed to confirm these results

  13. LevRad software as a tool to learn how to proceed with a shielding adequacy analysis

    International Nuclear Information System (INIS)

    Ferreira, C.C.; Oliveira, R.A.P.; Souza, S.O.

    2009-01-01

    Since the discovery of X-rays by Roentgen in 1895, several recommendations about the hazards from this radiation source have been published. About 14% of the total annual worldwide collective effective dose originates from the diagnostic X-rays examinations. In the UK, the collective effective dose from diagnostic X-rays examinations represents about 90% of the dose from all artificial sources. Diverse strategies have been performed, in an attempt to reduce the worldwide collective effective dose. We developed the LevRad software with the aim to teach how to proceed in an analysis of barriers shielding against diagnostic X-rays, to minimize the contact of the professional or the student with X-rays, and, finally, to prevent the consuming of the X-rays equipment. Some tests of the software were made, and preliminary results indicate that LevRad is efficient as a complementary tool for teaching professionals related to diagnostic radiology. In the case of the students, the advantage is perceived when using the software before the first contact with the X-rays equipment. The software introduces a solid knowledge about shielding adequacy analysis, prevents the consummation of the X-rays tube recurrent of the shielding adequacy analyses teaching and reduces the collective effective dose by avoiding the possible unnecessary exposures. (author)

  14. Hybridization Capture Using RAD Probes (hyRAD, a New Tool for Performing Genomic Analyses on Collection Specimens.

    Directory of Open Access Journals (Sweden)

    Tomasz Suchan

    Full Text Available In the recent years, many protocols aimed at reproducibly sequencing reduced-genome subsets in non-model organisms have been published. Among them, RAD-sequencing is one of the most widely used. It relies on digesting DNA with specific restriction enzymes and performing size selection on the resulting fragments. Despite its acknowledged utility, this method is of limited use with degraded DNA samples, such as those isolated from museum specimens, as these samples are less likely to harbor fragments long enough to comprise two restriction sites making possible ligation of the adapter sequences (in the case of double-digest RAD or performing size selection of the resulting fragments (in the case of single-digest RAD. Here, we address these limitations by presenting a novel method called hybridization RAD (hyRAD. In this approach, biotinylated RAD fragments, covering a random fraction of the genome, are used as baits for capturing homologous fragments from genomic shotgun sequencing libraries. This simple and cost-effective approach allows sequencing of orthologous loci even from highly degraded DNA samples, opening new avenues of research in the field of museum genomics. Not relying on the restriction site presence, it improves among-sample loci coverage. In a trial study, hyRAD allowed us to obtain a large set of orthologous loci from fresh and museum samples from a non-model butterfly species, with a high proportion of single nucleotide polymorphisms present in all eight analyzed specimens, including 58-year-old museum samples. The utility of the method was further validated using 49 museum and fresh samples of a Palearctic grasshopper species for which the spatial genetic structure was previously assessed using mtDNA amplicons. The application of the method is eventually discussed in a wider context. As it does not rely on the restriction site presence, it is therefore not sensitive to among-sample loci polymorphisms in the restriction sites

  15. Rad-hard embedded computers for nuclear robotics

    International Nuclear Information System (INIS)

    Giraud, A.; Joffre, F.; Marceau, M.; Robiolle, M.; Brunet, J.P.; Mijuin, D.

    1994-01-01

    Nuclear industries require robots with embedded rad hard electronics and high reliability. The SYROCO research program allowed to perform efficient industrial prototypes, build according to MICADO architecture, and to design CADMOS architecture. MICADO architecture uses the auto healing property that have CMOS circuits when being switched off during irradiation. (D.L.). 8 refs., 5 figs

  16. Effects of the rad52 gene on recombination in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Prakash, S.; Prakash, L.; Burke, W.; Montelone, B.A.

    1979-01-01

    Effects of the rad52 mutation in Saccharomyces cerevisiae on meiotic, γ-ray-induced, uv-induced, and spontaneous mitotic recombination were studied. The rad52/rad52 diploids undergo premeiotic DNA synthesis; sporulation occurs but inviable spores are produced. Intra- and intergenic recombination during meiosis were examined in cells transferred from sporulation medium to vegetative medium at different time intervals. No intragenic recombination was observed at the hisl-1/hisl-315 and trp5-2/trp5-48 heteroalleles. Gene-centromere recombination was also not observed in rad52/rad52 diploids. No γ-ray-induced intragenic mitotic recombination is seen in rad52/rad52 diploids and uv-induced intragenic recombination is greatly reduced. However, spontaneous mitotic recombination is not similarly affected. The RAD52 gene thus functions in recombination in meiosis and in γ-ray and uv-induced mitotic recombination but not in spontaneous mitotic recombination

  17. Germline RAD51B truncating mutation in a family with cutaneous melanoma

    DEFF Research Database (Denmark)

    Wadt, Karin A W; Aoude, Lauren G; Golmard, Lisa

    2015-01-01

    Known melanoma predisposition genes only account for around 40% of high-density melanoma families. Other rare mutations are likely to play a role in melanoma predisposition. RAD51B plays an important role in DNA repair through homologous recombination, and inactivation of RAD51B has been implicated...... in tumorigenesis. Thus RAD51B is a good candidate melanoma susceptibility gene, and previously, a germline splicing mutation in RAD51B has been identified in a family with early-onset breast cancer. In order to find genetic variants associated with melanoma predisposition, whole-exome sequencing was carried out...... on blood samples from a three-case cutaneous melanoma family. We identified a novel germline RAD51B nonsense mutation, and we demonstrate reduced expression of RAD51B in melanoma cells indicating inactivation of RAD51B. This is only the second report of a germline truncating RAD51B mutation. While...

  18. BNL ALARA center's development of a computerized Radiological Assessment and Design System (RADS)

    International Nuclear Information System (INIS)

    Dionne, B.J.; Connelly, J.M.

    1993-01-01

    The US Department of Energy's (DOE) Office of Health Physics and Industrial Hygiene sponsored a study of Radiological Engineering Programs at selected DOE contractor facilities. This study was conducted to review, evaluate, and summarize techniques and practices that should be considered in the design phase that reduce dose and the spread of radioactive materials during subsequent construction and operation at DOE radiological facilities. As in a previous study on operational ALARA programs, a variety of open-quotes good-practice documentsclose quotes will be generated. It is envisioned that these documents will serve as a resource to assist radiological engineers in the process of designing radiological facilities, and in performing radiological safety/ALARA design reviews. This paper presents the features for three good-practice documents and related software applications that are being developed based on the findings of this study. The proposed software called open-quotes Radiological Assessment and Design Systemclose quotes (RADS) will be a menu-driven database and spreadsheet program. It will be designed to provide easy, consistent, and effective implementation of the methodologies described in the three good-practice documents. These documents and the associated RADS software will provide the user with the following three functions: (1) enter dose assessment information and data into computer worksheets and provide printed tables of the results which can then be inserted into safety analysis reports or cost-benefit analysis, (2) perform a wide variety of sorts of radiological design criteria from DOE Orders and produce a checklist of the desired design criteria, and (3) enter cost/benefit data and qualitative ratings of attributes for various design alternatives which reduce dose into computer worksheets and provide printed reports of cost-effectiveness results

  19. BNL ALARA Center's development of a computerized radiological assessment and design system (RADS)

    International Nuclear Information System (INIS)

    Dionne, B.J.; Masciulli, S.; Connelly, J.M.

    1993-01-01

    The US Department of Energy's (DOE) Office of Health Physics and Industrial Hygiene sponsored a study of Radiological Engineering Programs at selected DOE contractor facilities. This study was conducted to review, evaluate, and summarize techniques and practices that should be considered in the design phase that reduce dose and the spread of radioactive materials during subsequent construction and operation of DOE radiological facilities. As in a previous study on operational ALARA programs, a variety of good-practice documents will be generated. It is envisioned that these documents will serve as a resource to assist radiological engineers in the process of designing radiological facilities, and in performing radiological safety/ALARA design reviews. This paper presents the features for three good-practice documents and related software applications that are being developed based on the findings of this study. The proposed software called Radiological Assessment and Design System (RADS) will be a menu-driven database and spreadsheet program. It will be designed to provide easy, consistent, and effective implementation of the methodologies described in the three good-practice documents. These documents and the associated RADS software will provide the user with the following three functions: (1) enter dose assessment information and data into computer worksheets and provide printed tables of the results which can then be inserted into safety analysis reports or cost-benefit analyses, (2) perform a wide variety of sorts of radiological design criteria from DOE Orders and produce a checklist of the desired design criteria, and (3) enter cost/benefit data and qualitative rating of attributes for various design alternatives which reduce dose into computer worksheets and provide printed reports of cost-effectiveness results

  20. Stratification of mammographic computerized analysis by BI-RADS categories

    Energy Technology Data Exchange (ETDEWEB)

    Lederman, Richard [Department of Radiology, Hadassah University Hospital, Ein Kerem, Jerusalem (Israel); Leichter, Isaac [Department of Electro-Optics, Jerusalem College of Technology, P.O.B. 16031, Jerusalem (Israel); Buchbinder, Shalom [Department of Radiology of The Montefiore Medical Center, The University Hospital for the Albert Einstein College of Medicine, Bronx, New York (United States); Novak, Boris [Department of Applied Mathematics, Jerusalem College of Technology, P.O.B. 16031, Jerusalem 91160 (Israel); Bamberger, Philippe [Department of Electronics, Jerusalem College of Technology, POB 16031, Jerusalem (Israel); Fields, Scott [Department of Radiology, Hadassah University Hospital, Mt. Scopus, Jerusalem (Israel)

    2003-02-01

    The Breast Imaging Reporting and Data System (BI-RADS) was implemented to standardize characterization of mammographic findings. The purpose of the present study was to evaluate in which BI-RADS categories the changes recommended by computerized mammographic analysis are most beneficial. Archival cases including, 170 masses (101 malignant, 69 benign) and 63 clusters of microcalcifications (MCs; 36 malignant, 27 benign), were evaluated retrospectively, using the BI-RADS categories, by several radiologists, blinded to the pathology results. A computerized system then automatically extracted from the digitized mammogram features characterizing mammographic lesions, which were used to classify the lesions. The results of the computerized classification scheme were compared, by receiver operating characteristics (ROC) analysis, to the conventional interpretation. In the ''low probability of malignancy group'' (excluding BI-RADS categories 4 and 5), computerized analysis improved the A{sub z}of the ROC curve significantly, from 0.57 to 0.89. In the ''high probability of malignancy group'' (mostly category 5) the computerized analysis yielded an ROC curve with an A {sub z}of 0.99. In the ''intermediate probability of malignancy group'' computerized analysis improved the A {sub z}significantly, from 0.66 for to 0.83. Pair-wise analysis showed that in the latter group the modifications resulting from computerized analysis were correct in 83% of cases. Computerized analysis has the ability to improve the performance of the radiologists exactly in the BI-RADS categories with the greatest difficulties in arriving at a correct diagnosis. It increased the performance significantly in the problematic group of ''intermediate probability of malignancy'' and pinpointed all the cases with missed cancers in the ''low probability'' group. (orig.)

  1. Stratification of mammographic computerized analysis by BI-RADS categories

    International Nuclear Information System (INIS)

    Lederman, Richard; Leichter, Isaac; Buchbinder, Shalom; Novak, Boris; Bamberger, Philippe; Fields, Scott

    2003-01-01

    The Breast Imaging Reporting and Data System (BI-RADS) was implemented to standardize characterization of mammographic findings. The purpose of the present study was to evaluate in which BI-RADS categories the changes recommended by computerized mammographic analysis are most beneficial. Archival cases including, 170 masses (101 malignant, 69 benign) and 63 clusters of microcalcifications (MCs; 36 malignant, 27 benign), were evaluated retrospectively, using the BI-RADS categories, by several radiologists, blinded to the pathology results. A computerized system then automatically extracted from the digitized mammogram features characterizing mammographic lesions, which were used to classify the lesions. The results of the computerized classification scheme were compared, by receiver operating characteristics (ROC) analysis, to the conventional interpretation. In the ''low probability of malignancy group'' (excluding BI-RADS categories 4 and 5), computerized analysis improved the A z of the ROC curve significantly, from 0.57 to 0.89. In the ''high probability of malignancy group'' (mostly category 5) the computerized analysis yielded an ROC curve with an A z of 0.99. In the ''intermediate probability of malignancy group'' computerized analysis improved the A z significantly, from 0.66 for to 0.83. Pair-wise analysis showed that in the latter group the modifications resulting from computerized analysis were correct in 83% of cases. Computerized analysis has the ability to improve the performance of the radiologists exactly in the BI-RADS categories with the greatest difficulties in arriving at a correct diagnosis. It increased the performance significantly in the problematic group of ''intermediate probability of malignancy'' and pinpointed all the cases with missed cancers in the ''low probability'' group. (orig.)

  2. Effect of Rad 51 overexpression on chromosomal stability and radiation sensitivity in tumour cells

    International Nuclear Information System (INIS)

    Jend, C.; Stuerzbecher, H.W.; Dikomey, E.; Borgmann, K.

    2004-01-01

    The present study was dedicated to examining the effects of Rad51 overexpression on genomic instability, expressed in terms of chromosomal aberrations in G1 and G2 phases following X-ray irradiation. For this purpose an osteosarcoma cell line (Ui-OS) which shows inducing Rad51 overexpression (UiRad5-2) after stable transfection was compared with an isogenetic line (UiLacZ) which overexpresses beta-galactosidase instead of Rad51 [de

  3. TOPBP1 regulates RAD51 phosphorylation and chromatin loading and determines PARP inhibitor sensitivity

    DEFF Research Database (Denmark)

    Moudry, Pavel; Watanabe, Kenji; Wolanin, Kamila M.

    2016-01-01

    to chromatin and formation of RAD51 foci, but without affecting the upstream HR steps of DNA end resection and RPA loading. Furthermore, TOPBP1 BRCT domains 7/8 are essential for RAD51 foci formation. Mechanistically, TOPBP1 physically binds PLK1 and promotes PLK1 kinase-mediated phosphorylation of RAD51...

  4. Disruption of mouse RAD54 reduces ionizing radiation resistance and homologous recombination.

    NARCIS (Netherlands)

    J. Essers (Jeroen); R.W. Hendriks (Rudi); S.M.A. Swagemakers (Sigrid); C. Troelstra (Christine); J. de Wit (Jan); D. Bootsma (Dirk); J.H.J. Hoeijmakers (Jan); R. Kanaar (Roland)

    1997-01-01

    textabstractDouble-strand DNA break (DSB) repair by homologous recombination occurs through the RAD52 pathway in Saccharomyces cerevisiae. Its biological importance is underscored by the conservation of many RAD52 pathway genes, including RAD54, from fungi to humans. We have analyzed the phenotype

  5. Interactions among Trypanosoma brucei RAD51 paralogues in DNA repair and antigenic variation

    Science.gov (United States)

    Dobson, Rachel; Stockdale, Christopher; Lapsley, Craig; Wilkes, Jonathan; McCulloch, Richard

    2011-01-01

    Homologous recombination in Trypanosoma brucei is used for moving variant surface glycoprotein (VSG) genes into expression sites during immune evasion by antigenic variation. A major route for such VSG switching is gene conversion reactions in which RAD51, a universally conserved recombinase, catalyses homology-directed strand exchange. In any eukaryote, RAD51-directed strand exchange in vivo is mediated by further factors, including RAD51-related proteins termed Rad51 paralogues. These appear to be ubiquitously conserved, although their detailed roles in recombination remain unclear. In T. brucei, four putative RAD51 paralogue genes have been identified by sequence homology. Here we show that all four RAD51 paralogues act in DNA repair, recombination and RAD51 subnuclear dynamics, though not equivalently, while mutation of only one RAD51 paralogue gene significantly impedes VSG switching. We also show that the T. brucei RAD51 paralogues interact, and that the complexes they form may explain the distinct phenotypes of the mutants as well as observed expression interdependency. Finally, we document the Rad51 paralogues that are encoded by a wide range of protists, demonstrating that the Rad51 paralogue repertoire in T. brucei is unusually large among microbial eukaryotes and that one member of the protein family corresponds with a key, conserved eukaryotic Rad51 paralogue. PMID:21615552

  6. ELDRS Characterization for a Very High Dose Mission

    Science.gov (United States)

    Harris, Richard D.; McClure, Steven S.; Rax, Bernard G.; Kenna, Aaron J.; Thorbourn, Dennis O.; Clark, Karla B.; Yan, Tsun-Yee

    2010-01-01

    Evaluation of bipolar linear parts which may have Enhanced Low Dose Rate Sensitivity (ELDRS) is problematic for missions that have very high dose radiation requirements. The accepted standards for evaluating parts that display ELDRS require testing at a very low dose rate which could be prohibitively long for very high dose missions. In this work, a methodology for ELDRS characterization of bipolar parts for mission doses up to 1 Mrad(Si) is evaluated. The procedure employs an initial dose rate of 0.01 rad(Si)/s to a total dose of 50 krad(Si) and then changes to 0.04 rad(Si)/s to a total dose of 1 Mrad(Si). This procedure appears to work well. No change in rate of degradation with dose has been observed when the dose rate is changed from 0.01 to 0.04 rad(Si)/s. This is taken as an indication that the degradation due to the higher dose rate is equivalent to that at the lower dose rate at the higher dose levels, at least for the parts studied to date. In several cases, significant parameter degradation or functional failure not observed at HDR was observed at fairly high total doses (50 to 250 krad(Si)) at LDR. This behavior calls into question the use of dose rate trend data and enhancement factors to predict LDR performance.

  7. Environmental radon with RAD7 detector; Radon ambiental con detector RAD7

    Energy Technology Data Exchange (ETDEWEB)

    Lopez M, A.; Balcazar, M. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Fernandez G, I. M.; Capote F, E., E-mail: arturo.lopez@inin.gob.mx [Centro de Proteccion e Higiene de las Radiaciones, Carretera La Victoria II Km 2.5 e/ Monumental y Final, Guanabacoa, La Habana (Cuba)

    2016-09-15

    Experimental results of the radon detection with the equipment RAD7 are presented. The use of a solid state detector placed in a semi-spherical chamber with an electric field allows a high sensitivity of 0.4 cpm/P Ci/l. Radon detection is achieved by the spectroscopy of its decay products. In accordance with a table of errors for various ranges of counts and radon concentrations, reported by the manufacturer, an equation was obtained that allows establishing operation criteria of the equipment. For radon detection at ambient concentrations as low as 30 Bq m{sup -3}, is shown that short counts of 10 minutes are good enough to make decisions on radiation protection matter. In places where concentrations are close to 200 Bq m{sup -3}, counting intervals of the order of 0.5 hours will have an acceptable counting error of the order of 20%. The determination of radon in soil was, according to the expected, on the order of 10 kBq m{sup -3}, and was found that even with the recommended counting times of 5 minutes, there is a risk of increased humidity inside the detector above 20% Rh, with associated reduction of detection efficiency, if the desiccant is not used properly. The equipment was subjected to a radon exposure in air of 13, 373 Bq m{sup -3} ± 3.7%, contained within a controlled chamber, with a variation in temperature of (19-21) degrees Celsius and in the relative humidity of (5-7) %, the good stability of the chamber allows to propose calibration processes of these equipment s by assessing the concentration by means of a Ge (Hp) detector. (Author)

  8. Low-dose x-radiation and congenital anomalies

    International Nuclear Information System (INIS)

    Kameyama, Yoshiro

    1983-01-01

    Among radiation effects on developing embryos and fetuses, occurrence of germinal mutation due to exposure of the gonads and postnatal manifestation of neoplasms are considered to be stochastic effects from the aspect of radiation protection. On the other hand, somatic effects such as teratogenic and embryo-toxic effects can be regarded as nonstochastic ones with threshold doses. In experimental teratological studies with mice and rats, the lowest radiation doses for manifestation of the non-stochastic somatic effects which have been recognized so far are:5 rad for resorption of preimplantation embryos; 5-10 rad for acute cytological changes such as pyknosis, cytoplasmic degeneration and mitotic delay; 5 rad for increasing frequency of spontaneous minor anomalies of the skeleton; 15-20 rad for malformations of the eye, brain and spinal cord; 20-25 rad for histogenetic and functional disorders of the central nervous system; and 20-25 rad for impaired fertility. Pregnant women who are subject to X-ray examinations are much concerned about potential hazard of radiation to their offspring in utero. The above experimental findings suggest that the possibility of non-stochastic somatic effects of diagnostic radiation on human embryos and fetuses is extremely low, and probably negligible, given the proper dose control measures. Possible effects which should be considered for risk evaluation of diagnostic exposure are two stochastic effects, carcinogenic and mutagenic. (author)

  9. Charpak, Garwin, propose unit for radiation dose

    CERN Multimedia

    Feder, Toni

    2002-01-01

    Becquerels, curries, grays, rads, rems, roentgens, sieverts - even for specialists the units of radiation can get confusing. That's why two eminent physicists, Georges Charpak of France, and Richard Garwin, are proposing the DARI as a unit of radiation dose they hope will help the public evaluate the risks associated with low-level radiation exposure (1 page)

  10. Derivation of cell population kinetic parameters from clinical statistical data (program RAD3)

    International Nuclear Information System (INIS)

    Cohen, L.

    1978-01-01

    Cellular lethality models generally require up to 6 parameters to simulate a clinical course of fractionated radiation therapy and to derive an estimate of the cellular surviving fraction for a given treatment scheme. These parameters are the mean cellular lethal dose, the extrapolation number, the ratio of sublethal to irreparable events, the regeneration rate, the repopulation limit (cell cycles), and a field-size or tumor-volume factor. A computer program (RAD3) was designed to derive best-fitting values for these parameters in relation to available clinical data based on the assumption that if a number of different fractionation schemes yield similar reactions, the cellular surviving fractions will be about equal in each instance. Parameters were derived for a variety of human tissues from which realistic iso-effect functions could be generated

  11. Stopping the greenhouse effect - recommendations submitted by the Bundestag Enquete Commission. - Why nuclear energy cannot solve the global-warming problem - on the urgency of a low-risk, efficient future energy economy. - The latest cancer statistics of the Hiroshima/Nagasaki A-bomb survivors - a higher radiation risk at dose rates below 50cGy (rad) - consequences for radiation protection

    International Nuclear Information System (INIS)

    Bach, W.; Kohler, S.; Koehnlein, W.

    1991-01-01

    The report compiles three contributions two of which discuss the issues of global warming, trace gases and ozone depletion. The measures proposed by a German enquete commision to stop the greenhouse effect, i.e. utilization of renewable energy sources, nuclear phaseout because nuclear power is not supposed to solve the global-warming problem, are described. The third contribution gives the latest cancer statistics of the Hiroshima/Nagasaki a-bomb survivors while taking into account the higher radiation risk due to low dose rates. (DG) [de

  12. NeuRad detector prototype pulse shape study

    Science.gov (United States)

    Muzalevsky, I.; Chudoba, V.; Belogurov, S.; Kiselev, O.; Bezbakh, A.; Fomichev, A.; Krupko, S.; Slepnev, R.; Kostyleva, D.; Gorshkov, A.; Ovcharenko, E.; Schetinin, V.

    2018-04-01

    The EXPERT setup located at the Super-FRS facility, the part of the FAIR complex in Darmstadt, Germany, is intended for investigation of properties of light exotic nuclei. One of its modules, the high granularity neutron detector NeuRad assembled from a large number of the scintillating fiber is intended for registration of neutrons emitted by investigated nuclei in low-energy decays. Feasibility of the detector strongly depends on its timing properties defined by the spatial distribution of ionization, light propagation inside the fibers, light emission kinetics and transition time jitter in the multi-anode photomultiplier tube. The first attempt of understanding the pulse formation in the prototype of the NeuRad detector by comparing experimental results and Monte Carlo (MC) simulations is reported in this paper.

  13. Low anterior anastomotic dehiscence following preoperative irradiation with 6000 rads

    Energy Technology Data Exchange (ETDEWEB)

    Blake, D.P.; Bubrick, M.P.; Kochsiek, G.G.; Feeney, D.A.; Johnston, G.R.; Strom, R.L.; Hitchcock, C.R.

    1984-03-01

    Twenty mongrel dogs received 6000 rads of irradiation to the rectum and colon using the Nominal Standard Dosage Equation. Three weeks after irradiation each dog underwent anterior resection of the rectosigmoid with reconstruction randomized to either an EEA stapled or a two layer handsewn anastomosis. Each dog was studied digitally and by barium enema at the time of surgery, on the seventh postoperative day, and at autopsy. Five clinically significant leaks and three radiographic leaks occurred in the EEA stapled anastomoses. The handsewn anastomoses had five clinically significant leaks and two radiographic leaks. The data indicate that low anterior resection with either an EEA stapled or handsewn anastomosis cannot be done safely after 6000 rad preoperative irradiation.

  14. Low anterior anastomotic dehiscence following preoperative irradiation with 6000 rads

    International Nuclear Information System (INIS)

    Blake, D.P.; Bubrick, M.P.; Kochsiek, G.G.; Feeney, D.A.; Johnston, G.R.; Strom, R.L.; Hitchcock, C.R.

    1984-01-01

    Twenty mongrel dogs received 6000 rads of irradiation to the rectum and colon using the Nominal Standard Dosage Equation. Three weeks after irradiation each dog underwent anterior resection of the rectosigmoid with reconstruction randomized to either an EEA stapled or a two layer handsewn anastomosis. Each dog was studied digitally and by barium enema at the time of surgery, on the seventh postoperative day, and at autopsy. Five clinically significant leaks and three radiographic leaks occurred in the EEA stapled anastomoses. The handsewn anastomoses had five clinically significant leaks and two radiographic leaks. The data indicate that low anterior resection with either an EEA stapled or handsewn anastomosis cannot be done safely after 6000 rad preoperative irradiation

  15. PI-RADS version 2: what you need to know

    International Nuclear Information System (INIS)

    Barrett, T.; Turkbey, B.; Choyke, P.L.

    2015-01-01

    Prostate cancer is the second most prevalent cancer in men worldwide and its incidence is expected to double by 2030. Multi-parametric magnetic resonance imaging (MRI) incorporating anatomical and functional imaging has now been validated as a means of detecting and characterising prostate tumours and can aid in risk stratification and treatment selection. The European Society of Urogenital Radiology (ESUR) in 2012 established the Prostate Imaging—Reporting and Data System (PI-RADS) guidelines aimed at standardising the acquisition, interpretation and reporting of prostate MRI. Subsequent experience and technical developments have highlighted some limitations, and a joint steering committee formed by the American College of Radiology, ESUR, and the AdMeTech Foundation have recently announced an updated version of the proposals. We summarise the main proposals of PI-RADS version 2, explore the evidence behind the recommendations, and highlight key differences for the benefit of those already familiar with the original.

  16. The response of mouse skin to multiple small doses of radiation

    International Nuclear Information System (INIS)

    Denekamp, J.; Harris, S.R.

    1975-01-01

    The response of mouse skin has been tested by irradiating the foot of albino mice and scoring erythema and desquamation during the following month. Multiple small doses of 150, 250 and 350 rad have been given 'daily', and the test dose necessary to achieve a given reaction has been determined one day after the last small fraction. This test dose has been compared with the single dose necessary to produce the same reaction level in previously untreated mice, in order to determine the ratio of the slopes of the dose-response curve at low and high doses: Slope ratio = (single dose - test dose)/total fractionated priming dose. In three separate experiments the slope ratio decreased as the dose per fraction was reduced from 350 to 150 rad. This conflicts with the data of Dutreix et al, who found a constant slope ratio over this dose range. The present data are compared with those obtained by Denekamp using 4, 9 and 14 fractions of 300 rad and by Douglas et al, using the same experimental technique, over the dose range 45 to 200 rad/fraction. In addition, the results from multifraction experiments in which equal dose increments were administered until the requisite skin reaction was achieved are also analysed in terms of their slope ratio (Fowler et al. Douglas et al). When all these results are plotted it is impossible to be sure whether the slope ratio is decreasing over the range 300 to 45 rad per fraction, although it seems likely. Most of the values at low doses lie in the range 0.15 to 0.25, indicating that at low doses the radiation is only 15 to 25% as effective per rad in causing cell death as at higher doses. (author)

  17. Radiomic modeling of BI-RADS density categories

    Science.gov (United States)

    Wei, Jun; Chan, Heang-Ping; Helvie, Mark A.; Roubidoux, Marilyn A.; Zhou, Chuan; Hadjiiski, Lubomir

    2017-03-01

    Screening mammography is the most effective and low-cost method to date for early cancer detection. Mammographic breast density has been shown to be highly correlated with breast cancer risk. We are developing a radiomic model for BI-RADS density categorization on digital mammography (FFDM) with a supervised machine learning approach. With IRB approval, we retrospectively collected 478 FFDMs from 478 women. As a gold standard, breast density was assessed by an MQSA radiologist based on BI-RADS categories. The raw FFDMs were used for computerized density assessment. The raw FFDM first underwent log-transform to approximate the x-ray sensitometric response, followed by multiscale processing to enhance the fibroglandular densities and parenchymal patterns. Three ROIs were automatically identified based on the keypoint distribution, where the keypoints were obtained as the extrema in the image Gaussian scale-space. A total of 73 features, including intensity and texture features that describe the density and the parenchymal pattern, were extracted from each breast. Our BI-RADS density estimator was constructed by using a random forest classifier. We used a 10-fold cross validation resampling approach to estimate the errors. With the random forest classifier, computerized density categories for 412 of the 478 cases agree with radiologist's assessment (weighted kappa = 0.93). The machine learning method with radiomic features as predictors demonstrated a high accuracy in classifying FFDMs into BI-RADS density categories. Further work is underway to improve our system performance as well as to perform an independent testing using a large unseen FFDM set.

  18. Quantitative comparison of mutagenic hazards: rad-equivalences

    International Nuclear Information System (INIS)

    1980-01-01

    The present situation concerning the problem of estimating genetic risks associated with the exposure of living beings, including man, to chemical compounds present in the environment is defined. Since these compounds affect the genetic material of cells by reactions similar to those produced by radiations, attempts have been made to establish rad-equivalences for some of these substances. This idea is discussed through the different publications mentioned [fr

  19. RadNet: Open network protocol for radiation data

    International Nuclear Information System (INIS)

    Rees, B.; Olson, K.; Beckes-Talcott, J.; Kadner, S.; Wenderlich, T.; Hoy, M.; Doyle, W.; Koskelo, M.

    1998-01-01

    Safeguards instrumentation is increasingly being incorporated into remote monitoring applications. In the past, vendors of radiation monitoring instruments typically provided the tools for uploading the monitoring data to a host. However, the proprietary nature of communication protocols lends itself to increased computer support needs and increased installation expenses. As a result, a working group of suppliers and customers of radiation monitoring instruments defined an open network protocol for transferring packets on a local area network from radiation monitoring equipment to network hosts. The protocol was termed RadNet. While it is now primarily used for health physics instruments, RadNet's flexibility and strength make it ideal for remote monitoring of nuclear materials. The incorporation of standard, open protocols ensures that future work will not render present work obsolete; because RadNet utilizes standard Internet protocols, and is itself a non-proprietary standard. The use of industry standards also simplifies the development and implementation of ancillary services, e.g. E-main generation or even pager systems

  20. Development of high integrity containers for rad-waste treatment

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yung Chul; Cho, Myung Sug; Jung, Yun Sub [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center

    1995-12-31

    Nuclear power plants are generating rad waste such as solid wastes, concentrated liquid wastes, spent resins and spent filters, and various types of imported containers which have different specifications and material properties are employed to handle the rad wastes according to facility characteristics of the plants or the type of wastes. These containers are stored at the intermediate storage facilities at the plant site due to the construction delay of permanent disposal site, and the additional construction of storage and disposal sites become more difficult with increase of the numbers and the operation time of the plants. In order to solve these difficulties, rad wastes volume reduction facilities such as High Pressure Compression Facility or Drying Facility are being installed and use of High Integrity Containers(HIC) are increasing. Therefore, we decide quality and technology standards required for the HIC, and then develop the HIC which satisfies the standards with new composite material called Steel Fiber Polymer Impregnated Concrete(SFPIC) (author). 84 refs., 118 figs.

  1. Development of high integrity containers for rad-waste treatment

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yung Chul; Cho, Myung Sug; Jung, Yun Sub [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center

    1996-12-31

    Nuclear power plants are generating rad waste such as solid wastes, concentrated liquid wastes, spent resins and spent filters, and various types of imported containers which have different specifications and material properties are employed to handle the rad wastes according to facility characteristics of the plants or the type of wastes. These containers are stored at the intermediate storage facilities at the plant site due to the construction delay of permanent disposal site, and the additional construction of storage and disposal sites become more difficult with increase of the numbers and the operation time of the plants. In order to solve these difficulties, rad wastes volume reduction facilities such as High Pressure Compression Facility or Drying Facility are being installed and use of High Integrity Containers(HIC) are increasing. Therefore, we decide quality and technology standards required for the HIC, and then develop the HIC which satisfies the standards with new composite material called Steel Fiber Polymer Impregnated Concrete(SFPIC) (author). 84 refs., 118 figs.

  2. Nucleotide sequence, transcript mapping, and regulation of the RAD2 gene of Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Madura, K.; Prakash, S.

    1986-01-01

    The authors determined the nucleotide sequence, mapped the 5' and 3' nRNA termini, and examined the regulation of the RAD2 gene of Saccharomyces cerevisiae. A long open reading frame within the RAD2 transcribed region encodes a protein of 1031 amino acids with a calculated molecular weight of 117,847. A disruption of the RAD2 gene that deletes the 78 carboxyl terminal codons results in loss of RAD2 function. The 5' ends of RAD2 mRNA show considerable heterogeneity, mapping 5 to 62 nucleotides upstream of the first ATG codon of the long RAD2 open reading frame. The longest RAD2 transcripts also contain a short open reading frame of 37 codons that precedes and overlaps the 5' end of the long RAD2 open reading frame. The RAD2 3' nRNA end maps 171 nucleotides downstream of the TAA termination codon and 20 nucleotides downstream from a 12-base-pair inverted repeat that might function in transcript termination. Northern blot analysis showed a ninefold increase in steady-state levels of RAD2 mRNA after treatment of yeast cells with UV light. The 5' flanking region of the RAD2 gene contains several direct and inverted repeats and a 44-nuclotide-long purine-rich tract. The sequence T G G A G G C A T T A A found at position - 167 to -156 in the RAD2 gene is similar to at sequence present in the 5' flanking regions of the RAD7 and RAD10 genes

  3. Performance characteristics of an independent dose verification program for helical tomotherapy

    Directory of Open Access Journals (Sweden)

    Isaac C. F. Chang

    2017-01-01

    Full Text Available Helical tomotherapy with its advanced method of intensity-modulated radiation therapy delivery has been used clinically for over 20 years. The standard delivery quality assurance procedure to measure the accuracy of delivered radiation dose from each treatment plan to a phantom is time-consuming. RadCalc®, a radiotherapy dose verification software, has released specifically for beta testing a module for tomotherapy plan dose calculations. RadCalc®'s accuracy for tomotherapy dose calculations was evaluated through examination of point doses in ten lung and ten prostate clinical plans. Doses calculated by the TomoHDA™ tomotherapy treatment planning system were used as the baseline. For lung cases, RadCalc® overestimated point doses in the lung by an average of 13%. Doses within the spinal cord and esophagus were overestimated by 10%. Prostate plans showed better agreement, with overestimations of 6% in the prostate, bladder, and rectum. The systematic overestimation likely resulted from limitations of the pencil beam dose calculation algorithm implemented by RadCalc®. Limitations were more severe in areas of greater inhomogeneity and less prominent in regions of homogeneity with densities closer to 1 g/cm3. Recommendations for RadCalc® dose calculation algorithms and anatomical representation were provided based on the results of the study.

  4. Performance and precision of double digestion RAD (ddRAD) genotyping in large multiplexed datasets of marine fish species

    DEFF Research Database (Denmark)

    Maroso, F.; Hillen, J E J; Pardo, B. G.

    2018-01-01

    ; (ii) the discrepancy between expected and observed tag length and coverage; (iii) the performances of reference based vs. de novo approaches; (iv) the sources of potential genotyping errors of the library preparation/bioinformatics protocol, by comparing technical replicates. Our results showed use...... a standardized protocol. A common bioinformatics pipeline based on STACKS was established, with and without the use of a reference genome. We performed analyses throughout the production and analysis of ddRAD data in order to explore (i) the loss of information due to heterogeneous raw read number across samples...... of downstream analysis carried out with ddRAD vs single SNP allele specific assay genotypes provided information about the levels of genotyping imprecision that can have a significant impact on allele frequency estimations and population assignment. The results and insights presented here will help to select...

  5. A comparison between rad-hard float zone silicon diodes as gamma dosimeter in radiation processing

    International Nuclear Information System (INIS)

    Camargo, Fábio de; Gonçalves, Josemary A.C.; Bueno, Carmen C.

    2017-01-01

    In this work, we report on the results obtained with rad-hard Standard Float Zone (STFZ) and Diffused Oxygenated Float Zone (DOFZ) silicon diodes in radiation processing dosimetry. The dosimetric probes were designed to operate in the direct current mode, as on-line radiation dosimeter. The irradiation of the samples was performed using a 60 Co source with a dose rate of almost 2.4 kGy/h. The current response of each diode was measured as a function of the exposure time in steps from 5 kGy up to 50 kGy to achieve a total absorbed dose of 275 kGy. In this dose range it is observed a significant decrease in the photocurrent generated in both devices due to gamma radiation defects produced in their active volumes. To mitigate this effect, the samples were pre-irradiated with 60 Co gamma rays at 700 kGy. Despite of being less sensitive, these devices presented stable and reproducible current signals with a relative sensitivity decrease of about 19% within the whole range of dose studied. The dose-response curves of the pre-irradiated diodes showed quadratic behavior with correlation coefficient higher than 0.9999 for total absorbed dose up to 275 kGy. The comparison of the FZ and DOFZ responses evidenced that the latter was slightly superior to the first. However, it is important to note that all pre-irradiated diodes can be used as gamma dosimeters in radiation processing applications. (author)

  6. A comparison between rad-hard float zone silicon diodes as gamma dosimeter in radiation processing

    Energy Technology Data Exchange (ETDEWEB)

    Camargo, Fábio de [Amazônia Azul Tecnologias de Defesa S.A. (AMAZUL), São Paulo, SP (Brazil); Gonçalves, Josemary A.C.; Bueno, Carmen C., E-mail: dcamargo@gmail.com, E-mail: ccbueno@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil)

    2017-07-01

    In this work, we report on the results obtained with rad-hard Standard Float Zone (STFZ) and Diffused Oxygenated Float Zone (DOFZ) silicon diodes in radiation processing dosimetry. The dosimetric probes were designed to operate in the direct current mode, as on-line radiation dosimeter. The irradiation of the samples was performed using a {sup 60}Co source with a dose rate of almost 2.4 kGy/h. The current response of each diode was measured as a function of the exposure time in steps from 5 kGy up to 50 kGy to achieve a total absorbed dose of 275 kGy. In this dose range it is observed a significant decrease in the photocurrent generated in both devices due to gamma radiation defects produced in their active volumes. To mitigate this effect, the samples were pre-irradiated with {sup 60}Co gamma rays at 700 kGy. Despite of being less sensitive, these devices presented stable and reproducible current signals with a relative sensitivity decrease of about 19% within the whole range of dose studied. The dose-response curves of the pre-irradiated diodes showed quadratic behavior with correlation coefficient higher than 0.9999 for total absorbed dose up to 275 kGy. The comparison of the FZ and DOFZ responses evidenced that the latter was slightly superior to the first. However, it is important to note that all pre-irradiated diodes can be used as gamma dosimeters in radiation processing applications. (author)

  7. Recovery of damage in rad-hard MOS devices during and after irradiation by electrons, protons, alphas, and gamma rays

    Science.gov (United States)

    Brucker, G. J.; Van Gunten, O.; Stassinopoulos, E. G.; Shapiro, P.; August, L. S.; Jordan, T. M.

    1983-01-01

    This paper reports on the recovery properties of rad-hard MOS devices during and after irradiation by electrons, protons, alphas, and gamma rays. The results indicated that complex recovery properties controlled the damage sensitivities of the tested parts. The results also indicated that damage sensitivities depended on dose rate, total dose, supply bias, gate bias, transistor type, radiation source, and particle energy. The complex nature of these dependencies make interpretation of LSI device performance in space (exposure to entire electron and proton spectra) difficult, if not impossible, without respective ground tests and analyses. Complete recovery of n-channel shifts was observed, in some cases within hours after irradiation, with equilibrium values of threshold voltages greater than their pre-irradiation values. This effect depended on total dose, radiation source, and gate bias during exposure. In contrast, the p-channel shifts recovered only 20 percent within 30 days after irradiation.

  8. Reaction kinetics of chemical pollutants as a basis of risk estimates in terms of rad-equivalence

    International Nuclear Information System (INIS)

    Ehrenberg, L.; Osterman-Golkar, S.

    1977-01-01

    Most mutagenic and carcinogenic chemicals are electrophilic agents or are converted to electrophilic agents in vivo. A majority of the effective genotoxic compounds are alkylating or arylating. The dose-response curve for mutation induced by alkylating agents is indicated to contain a linear component in the region of low doses. In this region the mutagenic effectiveness per unit dose was found for several alkylating agents to be approximately proportional to the calculated rate of reaction at a certain low nucleophilic strength. This proportionality appears, by and large, to be independent on the nature of the alkyl group introduced. Hence it is possible to ascribe a genetic risk to the degree of alkylation of these centers. This risk may be expressed in rad-equivalents

  9. Cloning of human and mouse genes homologous to RAD52, a yeast gene involved in DNA repair and recombination.

    NARCIS (Netherlands)

    D.F.R. Muris; O.Y. Bezzubova (Olga); J-M. Buerstedde; K. Vreeken; A.S. Balajee; C.J. Osgood; C. Troelstra (Christine); J.H.J. Hoeijmakers (Jan); K. Ostermann; H. Schmidt (Henning); A.T. Natarajan; J.C.J. Eeken; P.H.M. Lohmann (Paul); A. Pastink (Albert)

    1994-01-01

    textabstractThe RAD52 gene of Saccharomyces cerevisiae is required for recombinational repair of double-strand breaks. Using degenerate oligonucleotides based on conserved amino acid sequences of RAD52 and rad22, its counterpart from Schizosaccharomyces pombe, RAD52 homologs from man and mouse were

  10. Disparate requirements for the Walker A and B ATPase motifs of human RAD51D in homologous recombination.

    Science.gov (United States)

    Wiese, Claudia; Hinz, John M; Tebbs, Robert S; Nham, Peter B; Urbin, Salustra S; Collins, David W; Thompson, Larry H; Schild, David

    2006-01-01

    In vertebrates, homologous recombinational repair (HRR) requires RAD51 and five RAD51 paralogs (XRCC2, XRCC3, RAD51B, RAD51C and RAD51D) that all contain conserved Walker A and B ATPase motifs. In human RAD51D we examined the requirement for these motifs in interactions with XRCC2 and RAD51C, and for survival of cells in response to DNA interstrand crosslinks (ICLs). Ectopic expression of wild-type human RAD51D or mutants having a non-functional A or B motif was used to test for complementation of a rad51d knockout hamster CHO cell line. Although A-motif mutants complement very efficiently, B-motif mutants do not. Consistent with these results, experiments using the yeast two- and three-hybrid systems show that the interactions between RAD51D and its XRCC2 and RAD51C partners also require a functional RAD51D B motif, but not motif A. Similarly, hamster Xrcc2 is unable to bind to the non-complementing human RAD51D B-motif mutants in co-immunoprecipitation assays. We conclude that a functional Walker B motif, but not A motif, is necessary for RAD51D's interactions with other paralogs and for efficient HRR. We present a model in which ATPase sites are formed in a bipartite manner between RAD51D and other RAD51 paralogs.

  11. Disparate requirements for the Walker A and B ATPase motifs ofhuman RAD51D in homologous recombination

    Energy Technology Data Exchange (ETDEWEB)

    Wiese, Claudia; Hinz, John M.; Tebbs, Robert S.; Nham, Peter B.; Urbin, Salustra S.; Collins, David W.; Thompson, Larry H.; Schild, David

    2006-04-21

    In vertebrates, homologous recombinational repair (HRR) requires RAD51 and five RAD51 paralogs (XRCC2, XRCC3, RAD51B, RAD51C, and RAD51D) that all contain conserved Walker A and B ATPase motifs. In human RAD51D we examined the requirement for these motifs in interactions with XRCC2 and RAD51C, and for survival of cells in response to DNA interstrand crosslinks. Ectopic expression of wild type human RAD51D or mutants having a non-functional A or B motif was used to test for complementation of a rad51d knockout hamster CHO cell line. Although A-motif mutants complement very efficiently, B-motif mutants do not. Consistent with these results, experiments using the yeast two- and three-hybrid systems show that the interactions between RAD51D and its XRCC2 and RAD51C partners also require a functional RAD51D B motif, but not motif A. Similarly, hamster Xrcc2 is unable to bind to the non-complementing human RAD51D B-motif mutants in co-immunoprecipitation assays. We conclude that a functional Walker B motif, but not A motif, is necessary for RAD51D's interactions with other paralogs and for efficient HRR. We present a model in which ATPase sites are formed in a bipartite manner between RAD51D and other RAD51 paralogs.

  12. Influence of dose, dose rate, and radiation quality on radiation carcinogenesis and life shortening in RFM and BALB/C mice

    International Nuclear Information System (INIS)

    Ullrich, R.L.; Storer, J.B.

    1978-01-01

    The effects produced by 137 Cs gamma rays delivered at a high (45 rads/min) or intermediate (8.2 rads/day) dose rate and the effect of fission neutrons at a high (25 rads/min) and low (1 rad/day) rate in a population of nearly 30,000 RFM and 11,000 BALB/c mice have been studied. Gamma ray doses ranged from 10 to 400 rads with the RFM's and from 50-400 rads with the BALB/c's, while neutron doses ranged from 5 to 200 rads with both strains. The present paper will present an overview of these data and the general findings while subsequent publications will present detailed analyses of each aspect. A variety of neoplasms were sensitive to induction after radiation exposure, including tumors of both reticular tissue origin (leukemia, lymphoma, etc.) and solid tumors. For the RFM, thymic lymphomas were the dominant reticular tissue neoplasm while the majority of solid tumors were either lung adenomas or fit into the broad category of endocrine related tumors, including ovarian, pituitary, harderian, and uterine tumors. The BALB/c was much less sensitive to induction of reticular tissue neoplasms. The tumors that were most sensitive to induction included malignant lung carcinomas, mammary adenocarcinomas and ovarian tumors. In general for both life shortening and tumor induction after gamma ray exposures, when the low to intermediate dose range was sufficiently defined, linearity could be rejected and a dose squared or linear-dose squared relationship adequately fit the data. For neutron exposures, on the other hand, linear relationships were the general finding. The RBE for neutrons varied with tumor type and total dose level. For gamma ray irradiation, the intermediate dose rate resulted in a decreased effectiveness in all cases, while for neutron exposures the dose rate relationships were more complex

  13. The AtRAD21.1 and AtRAD21.3 Arabidopsis cohesins play a synergistic role in somatic DNA double strand break damage repair

    Czech Academy of Sciences Publication Activity Database

    da Costa-Nunes, J.A.; Capitao, C.; Kozák, Jaroslav; Costa-Nunes, P.; Ducasa, G.M.; Pontes, O.; Angelis, Karel

    2014-01-01

    Roč. 14, DEC 16 2014 (2014) ISSN 1471-2229 R&D Projects: GA MŠk(CZ) LD13006; GA ČR GA13-06595S Institutional support: RVO:61389030 Keywords : Arabidopsis * AtRAD21.1 * AtRAD21.3 Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.813, year: 2014

  14. RAD24 (=R1/sup S/) gene product of Saccharomyces cerevisiae participates in two different pathways of DNA repair

    International Nuclear Information System (INIS)

    Eckardt-Schupp, F.; Siede, W.; Game, J.C.

    1987-01-01

    The moderately UV- and X-ray-sensitive mutant of Saccharomyces cerevisiae originally designated r 1 /sup s/ complements all rad and mms mutants available. Therefore, the new nomination rad24-1 according to the RAD nomenclature is suggested. RAD24 maps on chromosome V, close to RAD3 (1.3 cM). In order to associate the RAD24 gene with one of the three repair pathways, double mutants of rad24 and various representative genes of each pathway were constructed. The UV and X-ray sensitivities of the double mutants compared to the single mutants indicate that RAD24 is involved in excision repair of UV damage (RAD3 epistasis group), as well as in recombination repair of UV and X-ray damage (RAD52 epistasis group). Properties of the mutant are discussed which hint at the control of late steps in the pathways

  15. Influence of dose rate of ionizing radiation on working capacity of the oil-filled electrical equipment for NPP; Vliyanie moshchnosti dozy ioniziruyushchego oblucheniya na rabotosposobnost` maslonapolnennogo ehlektrooborudovaniya dlya AEhS

    Energy Technology Data Exchange (ETDEWEB)

    Tyutnev, A P [and others

    1994-12-31

    Dependence of radiation electric conductivity transformer oil on the gamma radiation absorbed dose rate and on the energy proton flux is investigated. It is ascertained that the electrical reliability of oil and oil-barrier insulation does not depend on the absorbed dose rate up to the maximum achieved values of 200 rad/s.

  16. Effects of the rad52 gene on recombination in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Prakash, S.; Prakash, L.; Burke, W.; Montelone, B.A.

    1980-01-01

    Effects of the rad 52 mutation in Saccharomyces cerevisiae on meiotic, γ-ray-induced, uv-induced and spontaneous mitotic recombination were studied. The rad52/rad52 diploids undergo premeiotic DNA synthesis; sporulation occurs but inviable spores are produced. Both intra and intergenic recombination during meiosis were examined in cells transferred from sporulation medium to vegetative medium at different time intervals. No intragenic recombination was observed at the his1-1/his1-315 and trp-5-2/trp5-48 heteroalleles. Gene-centromere recombination also was not observed in rad/52/rad52 diploids. No γ-ray- or uv-induced intragenic mitotic recombination is seen in rad52/rad52 diploids. The rate of spontaneous mitotic recombination is lowered five-fold at the his1-1/his1-315 and leu1-c/leu1-12 heteroalleles. Spontaneous reversion rates of both his1-1 and his1-315 were elevated 10 to 20 fold in rad52/rad52 diploids. The RAD52 gene function is required for spontaneous mitotic recombination, uv- and γ-ray-induced mitotic recombination and mitotic recombination

  17. Caffeine inhibits gene conversion by displacing Rad51 from ssDNA

    Science.gov (United States)

    Tsabar, Michael; Mason, Jennifer M.; Chan, Yuen-Ling; Bishop, Douglas K.; Haber, James E.

    2015-01-01

    Efficient repair of chromosomal double-strand breaks (DSBs) by homologous recombination relies on the formation of a Rad51 recombinase filament that forms on single-stranded DNA (ssDNA) created at DSB ends. This filament facilitates the search for a homologous donor sequence and promotes strand invasion. Recently caffeine treatment has been shown to prevent gene targeting in mammalian cells by increasing non-productive Rad51 interactions between the DSB and random regions of the genome. Here we show that caffeine treatment prevents gene conversion in yeast, independently of its inhibition of the Mec1ATR/Tel1ATM-dependent DNA damage response or caffeine's inhibition of 5′ to 3′ resection of DSB ends. Caffeine treatment results in a dosage-dependent eviction of Rad51 from ssDNA. Gene conversion is impaired even at low concentrations of caffeine, where there is no discernible dismantling of the Rad51 filament. Loss of the Rad51 filament integrity is independent of Srs2's Rad51 filament dismantling activity or Rad51's ATPase activity and does not depend on non-specific Rad51 binding to undamaged double-stranded DNA. Caffeine treatment had similar effects on irradiated HeLa cells, promoting loss of previously assembled Rad51 foci. We conclude that caffeine treatment can disrupt gene conversion by disrupting Rad51 filaments. PMID:26019181

  18. CAD-RADS - a new clinical decision support tool for coronary computed tomography angiography.

    Science.gov (United States)

    Foldyna, Borek; Szilveszter, Bálint; Scholtz, Jan-Erik; Banerji, Dahlia; Maurovich-Horvat, Pál; Hoffmann, Udo

    2018-04-01

    Coronary computed tomography angiography (CTA) has been established as an accurate method to non-invasively assess coronary artery disease (CAD). The proposed 'Coronary Artery Disease Reporting and Data System' (CAD-RADS) may enable standardised reporting of the broad spectrum of coronary CTA findings related to the presence, extent and composition of coronary atherosclerosis. The CAD-RADS classification is a comprehensive tool for summarising findings on a per-patient-basis dependent on the highest-grade coronary artery lesion, ranging from CAD-RADS 0 (absence of CAD) to CAD-RADS 5 (total occlusion of a coronary artery). In addition, it provides suggestions for clinical management for each classification, including further testing and therapeutic options. Despite some limitations, CAD-RADS may facilitate improved communication between imagers and patient caregivers. As such, CAD-RADS may enable a more efficient use of coronary CTA leading to more accurate utilisation of invasive coronary angiograms. Furthermore, widespread use of CAD-RADS may facilitate registry-based research of diagnostic and prognostic aspects of CTA. • CAD-RADS is a tool for standardising coronary CTA reports. • CAD-RADS includes clinical treatment recommendations based on CTA findings. • CAD-RADS has the potential to reduce variability of CTA reports.

  19. Increased interreader agreement in diagnosis of hepatocellular carcinoma using an adapted LI-RADS algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Anton S., E-mail: anton.becker@usz.ch; Barth, Borna K.; Marquez, Paulo H.; Donati, Olivio F.; Ulbrich, Erika J.; Karlo, Christoph; Reiner, Cäcilia S.; Fischer, Michael A.

    2017-01-15

    Purpose: To evaluate a simplified Liver Imaging Reporting and Data System (LI-RADS) algorithm to improve interreader agreement while maintaining diagnostic performance for HCC. Materials and methods: MRI scans of 84 cirrhotic patients with 104 distinct liver observations were retrospectively selected to equivocally match each of the LI-RADS grades (LR1-5) using histopathology and imaging follow up as standard of reference. Four independent radiologists categorized all observations as benign (LR1-2) or potentially malignant (LR3-5) and determined LI-RADS based imaging features including observation size, arterial phase hyperenhancement, washout, capsule appearance and threshold growth for LR3-5 observations and timed their readouts. LR3-5 observations were categorized according to the LI-RADS v2014 algorithm and according to a modified LI-RADS (mLI-RADS) version. Diagnostic performance and Interreader agreement were determined for LI-RADS and mLI-RADS using receiver operating characteristics (ROC) and Fleiss’ and Cohen’s Kappa analysis respectively. Results: ROC analysis revealed equal diagnostic performance for LI-RADS and mLI-RADS (area under the ROC curve = 0.91). Interreader agreement was higher using mLI-RADS as compared to current LI-RADS showing an improved overall (κ = 0.53 ± 0.04 vs. 0.45 ± 0.04), and pair-wise agreement between most readers (κ range 0.44-0.62 vs. 0.35-0.60) at a reduced median evaluation time (51 vs. 62 s per observation, p < 0.0001). Conclusion: Focusing on observation size and washout criteria using a modified, stepwise LI-RADS decision tree for LR3-5 observations results in higher interobserver reliability and faster categorization while maintaining diagnostic accuracy.

  20. A Rad53 independent function of Rad9 becomes crucial for genome maintenance in the absence of the Recq helicase Sgs1.

    Directory of Open Access Journals (Sweden)

    Ida Nielsen

    Full Text Available The conserved family of RecQ DNA helicases consists of caretaker tumour suppressors, that defend genome integrity by acting on several pathways of DNA repair that maintain genome stability. In budding yeast, Sgs1 is the sole RecQ helicase and it has been implicated in checkpoint responses, replisome stability and dissolution of double Holliday junctions during homologous recombination. In this study we investigate a possible genetic interaction between SGS1 and RAD9 in the cellular response to methyl methane sulphonate (MMS induced damage and compare this with the genetic interaction between SGS1 and RAD24. The Rad9 protein, an adaptor for effector kinase activation, plays well-characterized roles in the DNA damage checkpoint response, whereas Rad24 is characterized as a sensor protein also in the DNA damage checkpoint response. Here we unveil novel insights into the cellular response to MMS-induced damage. Specifically, we show a strong synergistic functionality between SGS1 and RAD9 for recovery from MMS induced damage and for suppression of gross chromosomal rearrangements, which is not the case for SGS1 and RAD24. Intriguingly, it is a Rad53 independent function of Rad9, which becomes crucial for genome maintenance in the absence of Sgs1. Despite this, our dissection of the MMS checkpoint response reveals parallel, but unequal pathways for Rad53 activation and highlights significant differences between MMS- and hydroxyurea (HU-induced checkpoint responses with relation to the requirement of the Sgs1 interacting partner Topoisomerase III (Top3. Thus, whereas earlier studies have documented a Top3-independent role of Sgs1 for an HU-induced checkpoint response, we show here that upon MMS treatment, Sgs1 and Top3 together define a minor but parallel pathway to that of Rad9.

  1. Doses in radiation accidents investigated by chromosome aberration analysis

    International Nuclear Information System (INIS)

    Lloyd, D.C.; Purrott, R.J.; Prosser, J.S.; Lelliott, D.J.; Stimpson, L.D.

    1981-03-01

    The results are reviewed from investigations during 1980 into 68 cases of suspected overexposure to radiation. Of these, 37 were associated with industrial radiography, 11 with one or other of the major nuclear organisations and 20 with an institution of research, education or health. 55 of the dose estimates were in the range 0.0 - 0.09 Gy (0 - 9 rad) 5 in the range 0.1 - 0.29 Gy (10 - 29 rad) and for various reasons in 8 cases no biological assessment of dose was possible. The dose estimate for the case with the highest confirmed overexposure was 0.22 Gy (22 rads). The chromosome data are compared with information obtained from physical dosimetry and a brief summary is given of the circumstances of each case. (author)

  2. RadCon: A radiological consequences model. Technical guide - Version 2.0

    International Nuclear Information System (INIS)

    Crawford, J; Domel, R.U.; Harris, F.F.; Twining, J.R.

    2000-05-01

    A Radiological Consequence model (RadCon) is being developed at ANSTO to assess the radiological consequences, after an incident, in any climate, using appropriate meteorological and radiological transfer parameters. The major areas of interest to the developers are tropical and subtropical climates. This is particularly so given that it is anticipated that nuclear energy will become a mainstay for economies in these regions within the foreseeable future. Therefore, data acquisition and use of parameter values have been concentrated primarily on these climate types. Atmospheric dispersion and deposition for Australia can be modelled and supplied by the Regional Specialised Meteorological Centre (RSMC, one of five in the world) which is part of the Bureau of Meteorology Research Centre (BMRC), Puri et al. (1992). RadCon combines these data (i.e. the time dependent air and ground concentration generated by the dispersion model or measured quantities in the case of an actual incident) with specific regional parameter values to determine the dose to people via the major pathways of external and internal irradiation. For the external irradiation calculations, data are needed on lifestyle information such as the time spent indoors/outdoors, the high/low physical activity rates for different groups of people (especially critical groups) and shielding factors for housing types. For the internal irradiation calculations, data are needed on food consumption, effect of food processing, transfer parameters (soil to plant, plant to animal) and interception values appropriate for the region under study. Where the relevant data are not available default temperate data are currently used. The results of a wide ranging literature search has highlighted where specific research will be initiated to determine the information required for tropical and sub-tropical regions. The user is able to initiate sensitivity analyses within RadCon. This allows the parameters to be ranked in

  3. The growth and development of Schistosoma mansoni in mice exposed to sublethal doses of radiation

    International Nuclear Information System (INIS)

    Aitken, R.; Wilson, R.A.

    1989-01-01

    The maturation of Schistosoma mansoni was studied in mice exposed to various sublethal doses of radiation. Although the treatment of mice with 500 rads of radiation prior to infection did not alter parasite maturation, doses in excess of 500 rads led to a reduction in worm burden. This could not be attributed to a delay in the arrival of parasites in the hepatic portal system. Worms developing in mice treated with 800 rads commenced egg-laying about 1 wk later than worms in intact mice, and the rate of egg deposition appeared to be lower in irradiated hosts. The data demonstrate that exposure of C57BL/6 mice to doses of radiation in excess of 500 rads impairs their ability to carry infections of S. mansoni. The findings do not support the hypothesis that primary worm burdens in the mouse are controlled by a host immune response

  4. RadMAP: The Radiological Multi-sensor Analysis Platform

    International Nuclear Information System (INIS)

    Bandstra, Mark S.; Aucott, Timothy J.; Brubaker, Erik; Chivers, Daniel H.; Cooper, Reynold J.; Curtis, Joseph C.; Davis, John R.; Joshi, Tenzing H.; Kua, John; Meyer, Ross; Negut, Victor; Quinlan, Michael; Quiter, Brian J.; Srinivasan, Shreyas; Zakhor, Avideh; Zhang, Richard; Vetter, Kai

    2016-01-01

    The variability of gamma-ray and neutron background during the operation of a mobile detector system greatly limits the ability of the system to detect weak radiological and nuclear threats. The natural radiation background measured by a mobile detector system is the result of many factors, including the radioactivity of nearby materials, the geometric configuration of those materials and the system, the presence of absorbing materials, and atmospheric conditions. Background variations tend to be highly non-Poissonian, making it difficult to set robust detection thresholds using knowledge of the mean background rate alone. The Radiological Multi-sensor Analysis Platform (RadMAP) system is designed to allow the systematic study of natural radiological background variations and to serve as a development platform for emerging concepts in mobile radiation detection and imaging. To do this, RadMAP has been used to acquire extensive, systematic background measurements and correlated contextual data that can be used to test algorithms and detector modalities at low false alarm rates. By combining gamma-ray and neutron detector systems with data from contextual sensors, the system enables the fusion of data from multiple sensors into novel data products. The data are curated in a common format that allows for rapid querying across all sensors, creating detailed multi-sensor datasets that are used to study correlations between radiological and contextual data, and develop and test novel techniques in mobile detection and imaging. In this paper we will describe the instruments that comprise the RadMAP system, the effort to curate and provide access to multi-sensor data, and some initial results on the fusion of contextual and radiological data.

  5. RadMAP: The Radiological Multi-sensor Analysis Platform

    Energy Technology Data Exchange (ETDEWEB)

    Bandstra, Mark S., E-mail: msbandstra@lbl.gov [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Aucott, Timothy J. [Department of Nuclear Engineering, University of California Berkeley, CA (United States); Brubaker, Erik [Sandia National Laboratory, Livermore, CA (United States); Chivers, Daniel H.; Cooper, Reynold J. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Curtis, Joseph C. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Department of Nuclear Engineering, University of California Berkeley, CA (United States); Davis, John R. [Department of Nuclear Engineering, University of California Berkeley, CA (United States); Joshi, Tenzing H.; Kua, John; Meyer, Ross; Negut, Victor; Quinlan, Michael; Quiter, Brian J. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Srinivasan, Shreyas [Department of Nuclear Engineering, University of California Berkeley, CA (United States); Department of Electrical Engineering and Computer Science, University of California Berkeley, CA (United States); Zakhor, Avideh; Zhang, Richard [Department of Electrical Engineering and Computer Science, University of California Berkeley, CA (United States); Vetter, Kai [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Department of Nuclear Engineering, University of California Berkeley, CA (United States)

    2016-12-21

    The variability of gamma-ray and neutron background during the operation of a mobile detector system greatly limits the ability of the system to detect weak radiological and nuclear threats. The natural radiation background measured by a mobile detector system is the result of many factors, including the radioactivity of nearby materials, the geometric configuration of those materials and the system, the presence of absorbing materials, and atmospheric conditions. Background variations tend to be highly non-Poissonian, making it difficult to set robust detection thresholds using knowledge of the mean background rate alone. The Radiological Multi-sensor Analysis Platform (RadMAP) system is designed to allow the systematic study of natural radiological background variations and to serve as a development platform for emerging concepts in mobile radiation detection and imaging. To do this, RadMAP has been used to acquire extensive, systematic background measurements and correlated contextual data that can be used to test algorithms and detector modalities at low false alarm rates. By combining gamma-ray and neutron detector systems with data from contextual sensors, the system enables the fusion of data from multiple sensors into novel data products. The data are curated in a common format that allows for rapid querying across all sensors, creating detailed multi-sensor datasets that are used to study correlations between radiological and contextual data, and develop and test novel techniques in mobile detection and imaging. In this paper we will describe the instruments that comprise the RadMAP system, the effort to curate and provide access to multi-sensor data, and some initial results on the fusion of contextual and radiological data.

  6. 28 CFR 0.50 - General functions.

    Science.gov (United States)

    2010-07-01

    ..., including criminal prosecutions and civil actions and proceedings on behalf of the Government and appellate... Assistant Attorney General, Criminal Division: (1) Sections 591 through 593 and sections 595 through 612 of title 18, U.S. Code, relating to elections and political activities; (2) Sections 241, 242, and 594 of...

  7. The design of the Bulgaria rad waste repository

    International Nuclear Information System (INIS)

    Stefonova, I.; Petrov, I.; Navarro, M.; Sanchez, M.; Medinilla, G.

    2012-01-01

    In October 2011 a consortium composed by Westinghouse Engineering Spain SAU, ENRESA and DBE Technology GmbH was awarded a contract for the design of the Bulgaria rad waste repository. The facility, inspired in the spanish centre of El Cabril owned by ENRESA, will consist of a 66 reinforced concrete cells surface repository capable of receiving 18600 already conditioned waste containers of 20 t each, during 60 years, and the related auxiliary facilities and buildings. The project, representing a challenge because of the schedule and required level of detail, goes on fulfilling main milestones and getting customer satisfaction. (Author)

  8. Performance following a 500-675 rad neutron pulse

    International Nuclear Information System (INIS)

    Yochmowitz, M.G.; Brown, G.C.; Hardy, K.A.

    1985-01-01

    A three-light, three-lever discrete avoidance behavioral task was initiated to study the effects of a 500-675 rad neutron pulse upon performance. Eight primates performed the task for 4 h (3.5 h postexposure) on exposure day and for 4 h on each of 3 d postexposure. For the exposure day, five subjects had a decrease in correct responses, seven had increased reaction times, and six experienced productive emesis within 3.5 hours postexposure. Although the performance degradations were not severe, these data suggest that the performance of time critical tasks could be significantly impaired. 10 references

  9. Assessment of eye, hand and male gonadal skin dose in radiotherapy

    International Nuclear Information System (INIS)

    Pushap, M.P.S.

    1979-01-01

    An attempt has been made to gauge the dose to (1) the eye, (2) the skin of the hands and (3) the gonads from radiotherapy of other parts of the body. The study has been done on actual male patients at the Jorjani Medical Centre, Tehran. The study, indicated high dose to the eye lid i.e. about 3% of the tumour dose in the case of head irradiation. The eyes and gonads lie at unequal distances from thorax, so are their doses. It is further emphasised that a minimum dose of 400 rad in three weeks to one month has been reported to be cataractogenic in man. A 50% incidence of progressive loss of vision with a dose of 750 rad to 1000 rad in three weeks to three months time has been observed. If appropriate techniques are not employed to shield the eye, even from stray radiation, such limits may easily be reached. (K.B.)

  10. Recovery of deficient homologous recombination in Brca2-depleted mouse cells by wild-type Rad51 expression.

    Science.gov (United States)

    Lee, Shauna A; Roques, Céline; Magwood, Alissa C; Masson, Jean-Yves; Baker, Mark D

    2009-02-01

    The BRCA2 tumor suppressor is important in maintaining genomic stability. BRCA2 is proposed to control the availability, cellular localization and DNA binding activity of the central homologous recombination protein, RAD51, with loss of BRCA2 resulting in defective homologous recombination. Nevertheless, the roles of BRCA2 in regulating RAD51 and how other proteins implicated in RAD51 regulation, such as RAD52 and RAD54 function relative to BRCA2 is not known. In this study, we tested whether defective homologous recombination in Brca2-depleted mouse hybridoma cells could be rectified by expression of mouse Rad51 or the Rad51-interacting mouse proteins, Rad52 and Rad54. In the Brca2-depleted cells, defective homologous recombination can be restored by over-expression of wild-type mouse Rad51, but not mouse Rad52 or Rad54. Correction of the homologous recombination defect requires Rad51 ATPase activity. A sizeable fraction ( approximately 50%) of over-expressed wild-type Rad51 is nuclear localized. The restoration of homologous recombination in the presence of a low (i.e., non-functional) level of Brca2 by wild-type Rad51 over-expression is unexpected. We suggest that Rad51 may access the nuclear compartment in a Brca2-independent manner and when Rad51 is over-expressed, the normal requirement for Brca2 control over Rad51 function in homologous recombination is dispensable. Our studies support loss of Rad51 function as a critical underlying factor in the homologous recombination defect in the Brca2-depleted cells.

  11. Improvement of measuring methods and instrumentation concerning 222Rn determination in drinking waters – RAD7 and LSC technique comparison

    International Nuclear Information System (INIS)

    Stojković, Ivana; Tenjović, Branislava; Nikolov, Jovana; Vesković, Miroslav; Mrđa, Dušan; Todorović, Nataša

    2015-01-01

    A procedure for the determination of 222 Rn in environmental water samples using liquid scintillation counting (LSC) was applied and optimized. A minimum detectable activity of 0.029 Bq l −1 in a 20 ml glass vial (10 ml water sample mixed with 10 ml of liquid scintillation cocktail) has been achieved during 300 min of measurement time. The procedure was compared with RAD7 radon detector measurements. 226 Ra content in the water was determined by gamma-ray spectroscopy. Applications to drinking waters collected from public drinking fountains in the Vojvodina (Serbia) are presented with annual effective dose for ingestion and inhalation for adults calculated. - Highlights: • A procedure for the determination of 222 Rn in environmental water samples using liquid scintillation counting (LSC) was applied and optimized. • The procedure was compared with RAD7 radon detector measurements. • A minimum detectable activity of 0.029 Bq l −1 in 10 ml of sample has been achieved in glass vials during 300 min of measurement time. • 226 Ra content in the water was determined by gamma-ray spectroscopy. • Applications to drinking waters collected from public drinking fountains in the Vojvodina (Serbia) are presented with annual effective dose for ingestion and inhalation for adults calculated

  12. Mek1 Down Regulates Rad51 Activity during Yeast Meiosis by Phosphorylation of Hed1.

    Science.gov (United States)

    Callender, Tracy L; Laureau, Raphaelle; Wan, Lihong; Chen, Xiangyu; Sandhu, Rima; Laljee, Saif; Zhou, Sai; Suhandynata, Ray T; Prugar, Evelyn; Gaines, William A; Kwon, YoungHo; Börner, G Valentin; Nicolas, Alain; Neiman, Aaron M; Hollingsworth, Nancy M

    2016-08-01

    During meiosis, programmed double strand breaks (DSBs) are repaired preferentially between homologs to generate crossovers that promote proper chromosome segregation at Meiosis I. In many organisms, there are two strand exchange proteins, Rad51 and the meiosis-specific Dmc1, required for interhomolog (IH) bias. This bias requires the presence, but not the strand exchange activity of Rad51, while Dmc1 is responsible for the bulk of meiotic recombination. How these activities are regulated is less well established. In dmc1Δ mutants, Rad51 is actively inhibited, thereby resulting in prophase arrest due to unrepaired DSBs triggering the meiotic recombination checkpoint. This inhibition is dependent upon the meiosis-specific kinase Mek1 and occurs through two different mechanisms that prevent complex formation with the Rad51 accessory factor Rad54: (i) phosphorylation of Rad54 by Mek1 and (ii) binding of Rad51 by the meiosis-specific protein Hed1. An open question has been why inhibition of Mek1 affects Hed1 repression of Rad51. This work shows that Hed1 is a direct substrate of Mek1. Phosphorylation of Hed1 at threonine 40 helps suppress Rad51 activity in dmc1Δ mutants by promoting Hed1 protein stability. Rad51-mediated recombination occurring in the absence of Hed1 phosphorylation results in a significant increase in non-exchange chromosomes despite wild-type levels of crossovers, confirming previous results indicating a defect in crossover assurance. We propose that Rad51 function in meiosis is regulated in part by the coordinated phosphorylation of Rad54 and Hed1 by Mek1.

  13. Prolonged exposure to particulate chromate inhibits RAD51 nuclear import mediator proteins.

    Science.gov (United States)

    Browning, Cynthia L; Wise, John Pierce

    2017-09-15

    Particulate hexavalent chromium (Cr(VI)) is a human lung carcinogen and a human health concern. The induction of structural chromosome instability is considered to be a driving mechanism of Cr(VI)-induced carcinogenesis. Homologous recombination repair protects against Cr(VI)-induced chromosome damage, due to its highly accurate repair of Cr(VI)-induced DNA double strand breaks. However, recent studies demonstrate Cr(VI) inhibits homologous recombination repair through the misregulation of RAD51. RAD51 is an essential protein in HR repair that facilitates the search for a homologous sequence. Recent studies show prolonged Cr(VI) exposure prevents proper RAD51 subcellular localization, causing it to accumulate in the cytoplasm. Since nuclear import of RAD51 is crucial to its function, this study investigated the effect of Cr(VI) on the RAD51 nuclear import mediators, RAD51C and BRCA2. We show acute (24h) Cr(VI) exposure induces the proper localization of RAD51C and BRCA2. In contrast, prolonged (120h) exposure increased the cytoplasmic localization of both proteins, although RAD51C localization was more severely impaired. These results correlate temporally with the previously reported Cr(VI)-induced RAD51 cytoplasmic accumulation. In addition, we found Cr(VI) does not inhibit interaction between RAD51 and its nuclear import mediators. Altogether, our results suggest prolonged Cr(VI) exposure inhibits the nuclear import of RAD51C, and to a lesser extent, BRCA2, which results in the cytoplasmic accumulation of RAD51. Cr(VI)-induced inhibition of nuclear import may play a key role in its carcinogenic mechanism since the nuclear import of many tumor suppressor proteins and DNA repair proteins is crucial to their function. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Mek1 Down Regulates Rad51 Activity during Yeast Meiosis by Phosphorylation of Hed1.

    Directory of Open Access Journals (Sweden)

    Tracy L Callender

    2016-08-01

    Full Text Available During meiosis, programmed double strand breaks (DSBs are repaired preferentially between homologs to generate crossovers that promote proper chromosome segregation at Meiosis I. In many organisms, there are two strand exchange proteins, Rad51 and the meiosis-specific Dmc1, required for interhomolog (IH bias. This bias requires the presence, but not the strand exchange activity of Rad51, while Dmc1 is responsible for the bulk of meiotic recombination. How these activities are regulated is less well established. In dmc1Δ mutants, Rad51 is actively inhibited, thereby resulting in prophase arrest due to unrepaired DSBs triggering the meiotic recombination checkpoint. This inhibition is dependent upon the meiosis-specific kinase Mek1 and occurs through two different mechanisms that prevent complex formation with the Rad51 accessory factor Rad54: (i phosphorylation of Rad54 by Mek1 and (ii binding of Rad51 by the meiosis-specific protein Hed1. An open question has been why inhibition of Mek1 affects Hed1 repression of Rad51. This work shows that Hed1 is a direct substrate of Mek1. Phosphorylation of Hed1 at threonine 40 helps suppress Rad51 activity in dmc1Δ mutants by promoting Hed1 protein stability. Rad51-mediated recombination occurring in the absence of Hed1 phosphorylation results in a significant increase in non-exchange chromosomes despite wild-type levels of crossovers, confirming previous results indicating a defect in crossover assurance. We propose that Rad51 function in meiosis is regulated in part by the coordinated phosphorylation of Rad54 and Hed1 by Mek1.

  15. The measurement of the indoor absorbed dose rate in air in Beijing

    International Nuclear Information System (INIS)

    Guo Mingqiang; Pan Ziqiang; Yi Nanchang; Wei Zemin; Zhang Chao; Wang Huamin; Zhu Wencai

    1985-01-01

    This paper describes the indoor absorbed dose rate in air in Beijing. The average indoor absorbed dose rate in air is 8.29 μrad/h. The ratio of indoor to outdoor absorbed dose rate for 849 buildings is 1.51

  16. RAD21L, a novel cohesin subunit implicated in linking homologous chromosomes in mammalian meiosis.

    Science.gov (United States)

    Lee, Jibak; Hirano, Tatsuya

    2011-01-24

    Cohesins are multi-subunit protein complexes that regulate sister chromatid cohesion during mitosis and meiosis. Here we identified a novel kleisin subunit of cohesins, RAD21L, which is conserved among vertebrates. In mice, RAD21L is expressed exclusively in early meiosis: it apparently replaces RAD21 in premeiotic S phase, becomes detectable on the axial elements in leptotene, and stays on the axial/lateral elements until mid pachytene. RAD21L then disappears, and is replaced with RAD21. This behavior of RAD21L is unique and distinct from that of REC8, another meiosis-specific kleisin subunit. Remarkably, the disappearance of RAD21L at mid pachytene correlates with the completion of DNA double-strand break repair and the formation of crossovers as judged by colabeling with molecular markers, γ-H2AX, MSH4, and MLH1. RAD21L associates with SMC3, STAG3, and either SMC1α or SMC1β. Our results suggest that cohesin complexes containing RAD21L may be involved in synapsis initiation and crossover recombination between homologous chromosomes.

  17. Chemical dosimetry at less than 1000 rad: aqueous trimesic acid solutions

    International Nuclear Information System (INIS)

    Matthews, R.W.; Wilson, J.G.

    1981-01-01

    Aqueous solutions of trimesic acid were investigated for possible use as a chemical dosimeter. In aerated 10 -2 M sulphuric acid solution containing 10 -3 M trimesic acid, a highly fluorescent product is formed with its maximum fluorescence at 450nm when excited by 350nm light. The product has fluorescence characteristics very similar to quinine in 0.05 M sulphuric acid. The fluorescence intensity is linear with dose in the range 1-1000 rad and a precision of +-2% was obtained from a number of runs. Solutions are stable for at least several days before and after irradiation. The yield is little affected by moderate changes in trimesic acid concentration, oxygen concentration, water purity, energy of radiation and irradiation temperature. The small dependence of the yield on dose rate and the effect of measurement temperature on the fluorescence signal have been quantified. The most significant factor affecting the fluorescence signal is the hydrogen ion concentration of the solution. In aerated neutral and alkaline (pH 10) solutions, hydroxytrimesic acid (HTMA) is formed with G(HTMA) equal to 2.07 +- 0.04 and 2.21 +- 0.04, for 10 -3 M trimesate. In these solutions, G(HTMA) increases appreciably with increase in the trimesate concentration. The main fluorescent product formed in irradiated acid solutions was not identified but it was not HTMA. (author)

  18. Genetic injury in hybrid male mice exposed to low doses of 60CO γ-rays or fission neutrons. 1

    International Nuclear Information System (INIS)

    Grahn, D.; Carnes, B.A.; Farrington, B.H.; Lee, C.H.

    1984-01-01

    Young adult male B6CF 1 mice were exposed to single whole body doses of fission neutrons or 60 Co γ rays. Postspermatogonial dominant lethal injury, incidence of reciprocal chromosome translocations induced in spermatogonia, incidence of abnormal epididymal sperm 4-6 weeks after exposure, and testis weight loss 3-6 weeks after exposure were all measured. Significant effects were seen at 1 and 2.5 rad of neutrons consistent with extrapolation from higher doses, with the exception of dominant lethal mutations, which occurred in significant excess of expectation. Dose-response functions were linear or linear-quadratic, depending upon end point, radiation quality, and dose range. For translocation frequencies, the D 2 term was negative for neutron and positive for γ-ray irradiations. RBE values varied with dose and end point. For testis weight loss and abnormal sperm over the full dose range, the RBEs were between 5 and 6. They were between 7 and 9 at lower doses (< 10 rad) for translocations. RBEs for postimplantation and total dominant lethal rates were 5-6 above 10 rad and 10-14 below 10 rad. The RBEs for preimplant losses were between 15 and 25 above 10 rad and possibly higher below 10 rad, although the data are statistically 'noisy'. (Auth.)

  19. Stabilization of the ferromagnetic metallic state in rare earth-doped La0.49X0.01Ca0.50MnO3+δ (X=Nd, Sm, Gd and Yb)

    International Nuclear Information System (INIS)

    Aslam, Affia; Hasanain, S.K.; Akhtar, M.J.; Nadeem, M.

    2006-01-01

    We report the effects of disorder induced by a small amount of substitution of the smaller cations (Nd, Sm, Gd and Yb) for La in the La 0.50 Ca 0.50 MnO 3+δ system. With decreasing size of the dopant, the ferromagnetic and metallic state is stabilized while the AFM and insulating behaviour is completely eliminating. The magnetic moment below T c increases in general, with decreasing dopant size. The behaviour is interpreted in terms of the destabilization of the charge ordering (CO) due to the disorder induced by the size mismatch of the cations. Our data support the view that close to the COI-FM phase boundary, the effect of disorder is to weaken the CO that is more sensitive to disorder, whereas it leaves the more robust double exchange relatively unaffected, thereby extending the region in phase space where the FM phase is stable

  20. Response of human and rabbit lymphocytes to low doses of X-rays

    International Nuclear Information System (INIS)

    Fabry, L.

    1982-01-01

    The response of human and rabbit lymphocytes to low doses of X-rays was studied by the yields of dicentrics in first division metaphases. For both species, the dose-response curve was best fitted to the linear-quadratic model with a linear component predominating up to 67 and 42 rad respectively for man and rabbit. A calibration curve (5-400 rad) was obtained by combining the present results on man with previous data at higher doses. On the other hand, it appears that, at low doses, the radiosentivity of human lymphocytes is significantly higher than that of rabbit lymphocytes [fr

  1. Small dose multi-fractionation therapy, its radiobiological aspects and clinics

    International Nuclear Information System (INIS)

    Iwai, Hiroshi; Katagiri, Shiro; Furuhata, Akihiko; Fukusi, Itsuhisa

    1979-01-01

    Recent radiobiological data reveal that cell killings by small dose fractionation are almost due to nonrepairable damage with low oxygen enhancement ratio. Then, Small dose multi-fractionation method suggests a higher therapeutic-ratio than that in conventional high dose fractionated irradiation. Using these data of radiobiology, intermittent irradiations three times a day, four hours interval, with 60 - 80 rads for multi-fractionation, with high total doses of 7,200 - 7,500 rads/6.5 - 7 weeks mainly on bladder, laryngeal and esophageal tumour are applied. The results obtained are slightly improved. (author)

  2. Determination of stimulation effective dose of gamma ray on guinea pig to be used for antibody production

    International Nuclear Information System (INIS)

    Arifin, Muchson; Soewarsono, M.

    1983-01-01

    The experiment has been performed on guinea pigs which were irradiated by gamma rays with doses of 0, 150, 300 and 600 rad. Observations were carried out on peripheral blood in regard to red blood cell, white blood cell and haemoglobine, every week after irradiation. +he result obtained showed that 150 rad was the optimal stimulation effective dose for antibody production in guinea pigs. (author)

  3. Determination of stimulation effective dose of gamma ray on guinea pig to be used for antibody production

    Energy Technology Data Exchange (ETDEWEB)

    Arifin, M; Soewarsono, M [National Atomic Energy Agency, Jakarta (Indonesia). Pasar Djumat Research Centre

    1983-04-01

    The experiment has been performed on guinea pigs which were irradiated by gamma rays with doses of 0, 150, 300 and 600 rad. Observations were carried out on peripheral blood in regard to red blood cell, white blood cell and haemoglobine, every week after irradiation. The result obtained showed that 150 rad was the optimal stimulation effective dose for antibody production in guinea pigs. 10 refs.

  4. Characterization of the interaction between the cohesin subunits Rad21 and SA1/2.

    Directory of Open Access Journals (Sweden)

    Nenggang Zhang

    Full Text Available The cohesin complex is responsible for the fidelity of chromosomal segregation during mitosis. It consists of four core subunits, namely Rad21/Mcd1/Scc1, Smc1, Smc3, and one of the yeast Scc3 orthologs SA1 or SA2. Sister chromatid cohesion is generated during DNA replication and maintained until the onset of anaphase. Among the many proposed models of the cohesin complex, the 'core' cohesin subunits Smc1, Smc3, and Rad21 are almost universally displayed as tripartite ring. However, other than its supportive role in the cohesin ring, little is known about the fourth core subunit SA1/SA2. To gain deeper insight into the function of SA1/SA2 in the cohesin complex, we have mapped the interactive regions of SA2 and Rad21 in vitro and ex vivo. Whereas SA2 interacts with Rad21 through a broad region (301-750 aa, Rad21 binds to SA proteins through two SA-binding motifs on Rad21, namely N-terminal (NT and middle part (MP SA-binding motif, located at 60-81 aa of the N-terminus and 383-392 aa of the MP of Rad21, respectively. The MP SA-binding motif is a 10 amino acid, α-helical motif. Deletion of these 10 amino acids or mutation of three conserved amino acids (L(385, F(389, and T(390 in this α-helical motif significantly hinders Rad21 from physically interacting with SA1/2. Besides the MP SA-binding motif, the NT SA-binding motif is also important for SA1/2 interaction. Although mutations on both SA-binding motifs disrupt Rad21-SA1/2 interaction, they had no apparent effect on the Smc1-Smc3-Rad21 interaction. However, the Rad21-Rad21 dimerization was reduced by the mutations, indicating potential involvement of the two SA-binding motifs in the formation of the two-ring handcuff for chromosomal cohesion. Furthermore, mutant Rad21 proteins failed to significantly rescue precocious chromosome separation caused by depletion of endogenous Rad21 in mitotic cells, further indicating the physiological significance of the two SA-binding motifs of Rad21.

  5. Dynamic changes in Rad51 distribution on chromatin during meiosis in male and female vertebrates.

    Science.gov (United States)

    Ashley, T; Plug, A W; Xu, J; Solari, A J; Reddy, G; Golub, E I; Ward, D C

    1995-10-01

    Antibodies against human Rad51 protein were used to examine the distribution of Rad51 on meiotic chromatin in mouse spermatocytes and oocytes as well as chicken oocytes during sequential stages of meiosis. We observed the following dynamic changes in distribution of Rad51 during meiosis: (1) in early leptotene nuclei there are multiple, apparently randomly distributed, foci that by late leptonema become organized into tracks of foci. (2) These foci persist into zygonema, but most foci are now localized on Rad51-positive axes that correspond to lateral elements of the synaptonemal complex. As homologs synapse foci from homologous axes fuse. The distribution and involvement of Rad51 foci as contact points between homologs suggest that they may be components to early recombination nodules. (3) As pachynema progresses the number of foci drops dramatically; the temporal occurrence (mice) and physical and numerical distribution of foci on axes (chickens) suggest that they may be a component of late recombination nodules. (4) In early pachynema there are numerous Rad51 foci on the single axis of the X (mouse spermatocytes) or the Z (chicken oocytes) chromosomes that neither pair, nor recombine. (5) In late pachynema in mouse spermatocytes, but not oocytes, the Rad51 signal is preferentially enhanced at both ends of all the bivalents. As bivalents in spermatocytes, but not oocytes, begin to desynapse at diplonema they are often held together at these Rad51-positive termini. These observations parallel observations that recombination rates are exceptionally high near chromosome ends in male but not female eutherian mammals. (6) From diakinesis through metaphase I, Rad51 protein is detected as low-intensity fluorescent doublets that localize with CREST-specific antigens (kinetochores), suggesting that Rad51 participates, at least as a structural component of the materials involved, in sister kinetochore cohesiveness. Finally, the changes in Rad51 distribution during meiosis

  6. Total dose and dose rate radiation characterization of EPI-CMOS radiation hardened memory and microprocessor devices

    International Nuclear Information System (INIS)

    Gingerich, B.L.; Hermsen, J.M.; Lee, J.C.; Schroeder, J.E.

    1984-01-01

    The process, circuit discription, and total dose radiation characteristics are presented for two second generation hardened 4K EPI-CMOS RAMs and a first generation 80C85 microprocessor. Total dose radiation performance is presented to 10M rad-Si and effects of biasing and operating conditions are discussed. The dose rate sensitivity of the 4K RAMs is also presented along with single event upset (SEU) test data

  7. Single-dose-response curves of murine gastrointestinal crypt stem cells

    International Nuclear Information System (INIS)

    Masuda, K.; Withers, H.R.; Mason, K.A.; Chen, K.Y.

    1977-01-01

    Dose-response curves for the reproductive capacity of crypt stem cells of murine colonic, jejunal, and gastric mucosae exposed in situ to multifractionated gamma ray exposures were analyzed and single-dose-survival curves of these cells were constructed. The following conclusions were drawn: (1) The single-dose-response curves bend downward over a dose range of approximately 200 to 1500 rad; (2) cell death seems to be due to nonrepairable damage at doses less than 250 rad for colon, and 220 rad for jejunum; (3) there are 21, 110, and 140 stem cells per crypt of gastric, colonic, and jejunal mucosa, respectively; and (4) jejunal stem cells are the most radiosensitive and gastric mucosal stem cells are the most resistant

  8. Low morbidity following 9,000-rad intracavitary endocurietherapy (ECT) using the Kumar cervical applicator and external-beam radiotherapy (EXRT) in the management of carcinoma of the uterine cervix

    International Nuclear Information System (INIS)

    Kumar, P.P.; Good, R.R.; Scott, J.C.; Jones, E.O.; Lynch, G.; McCaul, G.F.

    1988-01-01

    The Kumar Cervical Applicator minimizes patient discomfort and improves patient mobility while reducing the tendency of the applicator to rotate during the 40 to 50 hours of uterine intracavitary endocurietherapy. Patients with previously untreated invasive carcinoma of the uterine cervix, F.I.G.O. stages IB-IVA, were treated with two Kumar intracavitary endocurietherapy (ECT) applications of 2,500 rad each to point ''A,'' and 4,000 rad external-beam radiotherapy (EXRT) to midplane, for a total dose of 9,000 rad. The major complication rate was 2.7 %, and the local control rate was 85 % (22/26 patients) for stage I and II, and 91 % (10/11 patients) for stage III and IVA. (author)

  9. Structural changes in mammalian cell DNA induced by low-dose x-ray damage and subsequent postirradiation incubation in the presence and absence of caffeine

    International Nuclear Information System (INIS)

    Wun, K.L.W.; Shafer, R.H.

    1982-01-01

    DNA damage and postirradiation incubation effects from X-ray doses of 30-2000 rad delivered to rat 9L cells in vitro were detemined by viscoelastic analysis of neutral (pH 7) cell lysates. Damage studies showed first an increase in the principal viscoelastic retardation time, T, with increasing dose, followed by a decrease, with the maximum retardation time occurring at 1000 rad. Also, the variation of retardation time with increasing postirradiation incubation time at 37 0 C was determined. At doses greater than 50 rad, this variation was quite complicated; e.g., following 100 rad, the retardation time showed a minimum followed by a maximum as a function of incubation time. All doses showed an initial return of T to close to control values at early times. Following 50 rad, control viscoelastic behavior was recovered in 1 hr. For doses of 100 rad and higher, 5 hr or more were required for complete return to control behavior has determined by both the value of T and the viscoelastic response to a probe dose of 200 rad immediately prior to lysis. These results are analyzed in terms of the dependence of the principal retardation time T on DNA molecular weight and conformation. Evidence is discussed indicating that the observed changes in T during postirradiation incubation reflect repair of DNA damage. Postirradiation incubation in the presence of 0.5 mM caffeine appeared to result in an inhibition of repair. In this case, both 30- and 50-rad doses required 5 hr for complete recovery of control behavior and showed the minimum and maximum in the T vs incubation time curve observed for incubation in the absence of caffeine following a dose of 100 rad

  10. Evaluation the total exposure of soil sample in Adaya site and the obtain risk assessments for the worker by Res Rad code program

    International Nuclear Information System (INIS)

    Mahadi, A. M.; Khadim, A. A. N.; Ibrahim, Z. H.; Ali, S. A.

    2012-12-01

    The present study aims to evaluation the total exposure to the worker in Adaya site risk assessment by using Res Rad code program. The study including 5 areas soil sample calculate in the site and analysis it by High Pure Germaniums (Hg) system made (CANBERRA) company. The soil sample simulation by (Res Rad) code program by inter the radioactive isotope concentration and the specification of the contamination zone area, depth and the cover depth of it. The total exposure of same sample was about 9 mSv/year and the (Heast 2001 Morbidity, FGR13 Morbidity) about 2.045 state every 100 worker in the year. There are simple different between Heast 2001 Morbidity and FGR13 Morbidity according to the Dose Conversion Factor (DCF) use it. The (FGR13 Morbidity) about 2.041 state every 100 worker in the year. (Author)

  11. Radiochromic Plastic Films for Accurate Measurement of Radiation Absorbed Dose and Dose Distributions

    DEFF Research Database (Denmark)

    McLaughlin, W. L.; Miller, Arne; Fidan, S.

    1977-01-01

    of dose rate (1–1014 rad s−1). Upon irradiation of the film, the profile of the radiation field is registered as a permanent colored image of the dose distribution. Unlike most other types of dyed plastic dose meters, the optical density produced by irradiation is in most cases stable for periods...... of many polymeric systems in industrial radiation processing. The result is that errors due to energy dependence of response of the radiation sensor are effectively reduced, since the spectral sensitivity of the dose meter matches that of the polymer of interest, over a wide range of photon and electron...

  12. Arabidopsis rad23-4 gene is required for pollen development under ...

    African Journals Online (AJOL)

    Nucleotide excision repair (NER) is a highly conserved DNA repair pathway for correcting DNA lesions that cause distortion of the double helical structure. The protein heterodimer Rad23 is involved in recognition and binding to such lesions. Here, we showed that rad23-4 (AT5g38470) was expressed in the roots, mature ...

  13. OsRAD51C Is Essential for Double Strand Break Repair in Rice Meiosis

    Directory of Open Access Journals (Sweden)

    Ding eTang

    2014-05-01

    Full Text Available RAD51C is one of the RAD51 paralogs that plays an important role in DNA double-strand break repair by homologous recombination. Here, we identified and characterized OsRAD51C, the rice homolog of human RAD51C. The Osrad51c mutant plant is normal in vegetative growth but exhibits complete male and female sterility. Cytological investigation revealed that homologous pairing and synapsis were severely disrupted. Massive chromosome fragmentation occurred during metaphase I in Osrad51c meiocytes, and was fully suppressed by the CRC1 mutation. Immunofluorescence analysis showed that OsRAD51C localized onto the chromosomes from leptotene to early pachytene during prophase I, and that normal loading of OsRAD51C was dependent on OsREC8, PAIR2, and PAIR3. Additionally, ZEP1 did not localize properly in Osrad51c, indicating that OsRAD51C is required for synaptonemal complex assembly. Our study also provided evidence in support of a functional divergence in RAD51C among organisms.

  14. Rad54 and Mus81 cooperation promotes DNA damage repair and restrains chromosome missegregation

    DEFF Research Database (Denmark)

    Ghamrasni, S El; Cardoso, R; Li, L

    2016-01-01

    . The inefficient repair of DNA double-strand breaks (DSBs) in Rad54(-/-)Mus81(-/-) cells was accompanied by elevated levels of chromosome missegregation and cell death. Perhaps as a consequence, tumor incidence in Rad54(-/-)Mus81(-/-) mice remained comparable to that in Mus81(-/-) mice. Our study highlights...

  15. Rad52 forms DMA repair and recombination centers during S phase

    DEFF Research Database (Denmark)

    Lisby, M.; Rothstein, R.; Mortensen, Uffe Hasbro

    2001-01-01

    fluorescent protein (GFP) is fully functional in DNA repair and recombination. After induction of DNA double-strand breaks by gamma -irradiation, meiosis, or the HO endonuclease, Rad52-GFP relocalizes from a diffuse nuclear distribution to distinct foci. Interestingly, Rad52 foci are formed almost exclusively...

  16. Ago2 facilitates Rad51 recruitment and DNA double-strand break repair by homologous recombination

    DEFF Research Database (Denmark)

    Gao, Min; Wei, Wei; Li, Ming Hua

    2014-01-01

    resection as well as RPA and Mre11 loading is unaffected by Ago2 or Dicer depletion, suggesting that Ago2 very likely functions directly in mediating Rad51 accumulation at DSBs. Taken together, our findings suggest that guided by diRNAs, Ago2 can promote Rad51 recruitment and/or retention at DSBs...

  17. 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

  18. Enhancement of the RAD51 Recombinase Activity by the Tumor Suppressor PALB2

    Energy Technology Data Exchange (ETDEWEB)

    Dray, Eloise; Etchin, Julia; Wiese, Claudia; Saro, Dorina; Williams, Gareth J.; Hammel, Michal; Yu, Xiong; Galkin, Vitold E.; Liu, Dongqing; Tsai, Miaw-Sheue; Sy, Shirley M-H.; Egelman, Edward; Chen, Junjie; Sung, Patrick; Schild, D.

    2010-08-24

    Homologous recombination mediated by the RAD51 recombinase helps eliminate chromosomal lesions, such as DNA double-stranded breaks induced by radiation or arising from injured DNA replication forks. The tumor suppressors BRCA2 and PALB2 act together to deliver RAD51 to chromosomal lesions to initiate repair. Here we document a new function of PALB2 in the enhancement of RAD51's ability to form the D-loop. We show that PALB2 binds DNA and physically interacts with RAD51. Importantly, while PALB2 alone stimulates D-loop formation, a cooperative effect is seen with RAD51AP1, an enhancer of RAD51. This stimulation stems from PALB2's ability to function with RAD51 and RAD51AP1 to assemble the synaptic complex. Our results help unveil a multi-faceted role of PALB2 in chromosome damage repair. Since PALB2 mutations can cause breast and other tumors or lead to Fanconi anemia, our findings are important for understanding the mechanism of tumor suppression in humans.

  19. RAD6 gene of Saccharomyces cerevisiae encodes a protein containing a tract of 13 consecutive aspartates

    International Nuclear Information System (INIS)

    Reynolds, P.; Weber, S.; Prakash, L.

    1985-01-01

    The RAD6 gene of Saccharomyces cerevisiae is required for postreplication repair of UV-damaged DNA, for induced mutagenesis, and for sporulation. The authors have mapped the transcripts and determined the nucleotide sequence of the cloned RAD6 gene. The RAD6 gene encodes two transcripts of 0.98 and 0.86 kilobases which differ only in their 3' termini. The transcribed region contains an open reading frame of 516 nucleotides. The rad6-1 and rad6-3 mutant alleles, which the authors have cloned and sequenced, introduce amber and ochre nonsense mutations, respectively into the open reading frame, proving that it encodes the RAD6 protein. The RAD6 protein predicted by the nucleotide sequence is 172 amino acids long, has a molecular weight of 19,704, and contains 23.3% acidic and 11.6% basic residues. Its most striking feature is the highly acidic carboxyl terminus: 20 of the 23 terminal amino acids are acidic, including 13 consecutive aspartates. RAD6 protein thus resembles high mobility group proteins HMG-1 and HMG-2, which each contain a carboxyl-proximal tract of acidic amino acids. 48 references, 6 figures

  20. Rad52 multimerization is important for its nuclear localization in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Plate, Iben; Albertsen, Line; Lisby, Michael

    2008-01-01

    Rad52 is essential for all homologous recombination and DNA double strand break repair events in Saccharomyces cerevisiae. This protein is multifunctional and contains several domains that allow it to interact with DNA as well as with different repair proteins. However, it has been unclear how Rad...

  1. Location of RAD51-like protein during meiotic prophase in Eimeria tenella.

    Science.gov (United States)

    Del Cacho, Emilio; Gallego, Margarita; Pagés, Marc; Barbero, José Luís; Monteagudo, Luís; Sánchez-Acedo, Caridad

    2011-05-31

    This study focuses on reporting events in Eimeria tenella oocysts from early to late prophase I in terms of RAD51 protein in association with the synaptonemal complex formed between homologous chromosomes. The aim of the study was the sequential localization of RAD51 protein, which is involved in the repair of double-strand breaks (DSBs) on the eimerian chromosomes as they synapse and desynapse. Structural Maintenance of Chromosome protein SMC3, which plays a role in synaptonemal complex formation, was labeled to identify initiation and progress of chromosome synapsis and desynapsis in parallel with the appearance and disappearance of RAD51 foci. Antibodies directed against RAD51 and cohesin subunit SMC3 proteins were labeled with either fluorescence or colloidal gold to visualize RAD51 protein foci and synaptonemal complexes. RAD51 protein localization during prophase I was studied on meiotic chromosomes spreads obtained from oocysts at different points in time after the start of sporulation. The present findings showed that foci detected with the antibody directed against RAD51 protein first appeared at the pre-leptotene stage before homologous chromosomes began pairing. Subsequently, the foci were detected in association with the lateral elements at the precise sites where synapsis were in progress. These findings lead us to suggest that in E. tenella, homologous chromosome pairing was a DSB-dependent mechanism and reinforced the participation of RAD51 protein in meiotic homology search, alignment and pairing of chromosomes. Copyright © 2010 Elsevier B.V. All rights reserved.

  2. Comparison of clastogen-induced gene expression profiles in wild-type and DNA repair-deficient Rad54/Rad54B cells

    Directory of Open Access Journals (Sweden)

    van Benthem Jan

    2010-01-01

    Full Text Available Abstract Background Previously we found that Rad54/Rad54B cells are more sensitive towards mitomycin C (MMC as compared to wild-type (WT cells. This difference in sensitivity was absent upon exposure to other clastogens like bleomycin (BLM and γ-radiation. In order to get further insight into possible underlying mechanisms, gene expression changes in WT and Rad54/Rad54B MEFs (mouse embryonic fibroblasts after exposure to the clastogens MMC and BLM were investigated. Exposures of these cells to mutagens (N-ac-AAF and ENU and vehicle were taken as controls. Results Most exposures resulted in an induction of DNA damage signaling and apoptosis genes and a reduced expression of cell division genes in cells of both genotypes. As expected, responses to N-ac-AAF were very similar in both genotypes. ENU exposure did not lead to significant gene expression changes in cells of both genotypes, presumably due to its short half-life. Gene expression responses to clastogens, however, showed a genotype-dependent effect for BLM and MMC. MMC treated Rad54/Rad54B MEFs showed no induction of p53-signaling, DNA damage response and apoptosis as seen for all the other treatments. Conclusion These data support our finding that different types of clastogens exist and that responses to these types depend on the DNA repair status of the cells.

  3. Characterisation of the novel deleterious RAD51C p.Arg312Trp variant and prioritisation criteria for functional analysis of RAD51C missense changes.

    Science.gov (United States)

    Gayarre, Javier; Martín-Gimeno, Paloma; Osorio, Ana; Paumard, Beatriz; Barroso, Alicia; Fernández, Victoria; de la Hoya, Miguel; Rojo, Alejandro; Caldés, Trinidad; Palacios, José; Urioste, Miguel; Benítez, Javier; García, María J

    2017-09-26

    Despite a high prevalence of deleterious missense variants, most studies of RAD51C ovarian cancer susceptibility gene only provide in silico pathogenicity predictions of missense changes. We identified a novel deleterious RAD51C missense variant (p.Arg312Trp) in a high-risk family, and propose a criteria to prioritise RAD51C missense changes qualifying for functional analysis. To evaluate pathogenicity of p.Arg312Trp variant we used sequence homology, loss of heterozygosity (LOH) and segregation analysis, and a comprehensive functional characterisation. To define a functional-analysis prioritisation criteria, we used outputs for the known functionally confirmed deleterious and benign RAD51C missense changes from nine pathogenicity prediction algorithms. The p.Arg312Trp variant failed to correct mitomycin and olaparib hypersensitivity and to complement abnormal RAD51C foci formation according to functional assays, which altogether with LOH and segregation data demonstrated deleteriousness. Prioritisation criteria were based on the number of predictors providing a deleterious output, with a minimum of 5 to qualify for testing and a PredictProtein score greater than 33 to assign high-priority indication. Our study points to a non-negligible number of RAD51C missense variants likely to impair protein function, provides a guideline to prioritise and encourage their selection for functional analysis and anticipates that reference laboratories should have available resources to conduct such assays.

  4. Doses to early entrants to the A-bombed areas and to residents of the fallout areas and 137Cs in soil of the 'black rain' area in Hiroshima

    International Nuclear Information System (INIS)

    Takeshita, Kenji

    1976-01-01

    An external exposure dose from residual activity (induced radioactivity in the fallout areas and radioactive fallout in the ''black rain'' area) caused by an atomic bomb in Hiroshima was estimated. The integrated doses to the infinite time averaged 101 rads in the atomic bombed area of Hiroshima and 32 rads in that area of Nagasaki. According to the measurement by investigators, the integrated doses of the external exposure dose due to radioactive fallout averaged 13 rads. The amount of 137 Cs in soils was determined in the southest slanting surface

  5. Estimate of whole body doses for Lynette Tew and Becky Farnsworth from Nevada Test Site local fallout

    International Nuclear Information System (INIS)

    Anspaugh, L.R.; Ng, Y.C.

    1985-01-01

    Lynette Tew and Becky Farnsworth are decendents whose relatives are litigants in Timothy vs US. The litigants allege that the decendents were harmed by radiation doses received as a result of local fallout from the testing of nuclear weapons at the Nevada Test Site. We have calculated a best estimate of the whole body dose received by each decendent from external exposure and the ingestion of radionuclides with food. In each case the dose via ingestion is trivial compared to the external dose. For Lynette Tew the dose estimate is 0.28 rads. For Becky Farnsworth it is 0.0035 rads. 23 references, 4 tables

  6. Rad9 contribution to radiosensitivity and the G2 checkpoint in a DT40 cell line

    Energy Technology Data Exchange (ETDEWEB)

    Kumano, Tomoyasu [Kanazawa Univ. (Japan). Graduate School of Medical Science

    2002-12-01

    In fission yeast, the rad9 (radiation sensitive) gene was cloned from a mutant that is sensitive to ionizing radiation, ultraviolet and hydroxyurea. This gene has also been shown to be required for a DNA damage checkpoint. Orthologues of the rad9 gene have recently been identified in higher eukaryote cells including human. Here we generated Rad9 knockout (Rad9-/-) cells from the chicken B lymphocyte line DT40 to examine the role of Rad9 in higher eukaryotes. First we isolated a part of the chicken Rad9 gene which was 54% identical with human Rad9 at the amino acid sequence level. Next we isolated genomic clones, determined exons and introns, and constructed targeting vectors designed to disrupt exon 1-3 of the chicken Rad9 gene by replacement with a drug-resistant gene. Successful targeted integration was verified by Southern blot analysis and the disruption of the Rad9 gene was confirmed by reverse transcription polymerase chain reaction (RT-PCR). To analyze the radiosensitivity of these Rad9-/- cells, we monitored the clonogenic survival after various degrees of X-ray irradiation. Rad9-/- cells were more sensitive to X-rays than wild type cells at all dosages. However, these cells were less sensitive than ATM knockout (ATM-/-) cells that are known to be X-ray sensitive and that showed a defective checkpoint control. In contrast, Rad9-/- cells were markedly more sensitive to ultraviolet and hydroxyruea. In addition, we assessed the G2 checkpoint by measurement of the mitotic index that is the fraction of the accumulating number of cells in mitosis at various times after X-ray irradiation. While the number of mitotic wild type cells did not increase until 2 hrs after X-ray irradiation, the number of mitotic Rad9-/- cells showed an increase similar to that of ATM-/- cells. These results suggest that just as in fission yeast, in higher eukaryotes Rad9 also contributes to X-ray, ultraviolet and hydroxyurea sensitivity, and plays an important role in the G2 checkpoint

  7. Rad9 contribution to radiosensitivity and the G2 checkpoint in a DT40 cell line

    International Nuclear Information System (INIS)

    Kumano, Tomoyasu

    2002-01-01

    In fission yeast, the rad9 (radiation sensitive) gene was cloned from a mutant that is sensitive to ionizing radiation, ultraviolet and hydroxyurea. This gene has also been shown to be required for a DNA damage checkpoint. Orthologues of the rad9 gene have recently been identified in higher eukaryote cells including human. Here we generated Rad9 knockout (Rad9-/-) cells from the chicken B lymphocyte line DT40 to examine the role of Rad9 in higher eukaryotes. First we isolated a part of the chicken Rad9 gene which was 54% identical with human Rad9 at the amino acid sequence level. Next we isolated genomic clones, determined exons and introns, and constructed targeting vectors designed to disrupt exon 1-3 of the chicken Rad9 gene by replacement with a drug-resistant gene. Successful targeted integration was verified by Southern blot analysis and the disruption of the Rad9 gene was confirmed by reverse transcription polymerase chain reaction (RT-PCR). To analyze the radiosensitivity of these Rad9-/- cells, we monitored the clonogenic survival after various degrees of X-ray irradiation. Rad9-/- cells were more sensitive to X-rays than wild type cells at all dosages. However, these cells were less sensitive than ATM knockout (ATM-/-) cells that are known to be X-ray sensitive and that showed a defective checkpoint control. In contrast, Rad9-/- cells were markedly more sensitive to ultraviolet and hydroxyruea. In addition, we assessed the G2 checkpoint by measurement of the mitotic index that is the fraction of the accumulating number of cells in mitosis at various times after X-ray irradiation. While the number of mitotic wild type cells did not increase until 2 hrs after X-ray irradiation, the number of mitotic Rad9-/- cells showed an increase similar to that of ATM-/- cells. These results suggest that just as in fission yeast, in higher eukaryotes Rad9 also contributes to X-ray, ultraviolet and hydroxyurea sensitivity, and plays an important role in the G2 checkpoint

  8. A RAD approach to client/server system development

    International Nuclear Information System (INIS)

    Brule, M.; Fair, W.; Jiang, J.; Sanvido, R.

    1995-01-01

    The capability, richness, and leverage of inexpensive commercial operating systems, off-the-shelf applications, and powerful developing tools have made building feature-rich client/server systems possible in rapid time and at low cost--ushering in a new level of systems integration not before possible. The authors achieve rapid application development (RAD) by using a flexible and extendible client/service integration framework. The framework provides the means to integrate in-house and third-party software applications with databases and expert-system knowledge bases and, where appropriate, provides communication links among the applications. The authors discuss the integration framework's capabilities, explain its underlying system architecture, and outline the methods and tools used to customize and integrate many diverse applications

  9. The role of RAD51 in etoposide (VP16) resistance in small cell lung cancer

    DEFF Research Database (Denmark)

    Hansen, Lasse Tengbjerg; Lundin, Cecilia; Spang-Thomsen, Mogens

    2003-01-01

    Etoposide (VP16) is a potent inducer of DNA double-strand breaks (DSBs) and is efficiently used in small cell lung cancer (SCLC) therapy. However, acquired VP16 resistance remains an important barrier to effective treatment. To understand the underlying mechanisms for VP16 resistance in SCLC, we...... investigated DSB repair and cellular VP16 sensitivity of SCLC cells. VP16 sensitivity and RAD51, DNA-PK(cs), topoisomerase IIalpha and P-glycoprotein protein levels were determined in 17 SCLC cell lines. In order to unravel the role of RAD51 in VP16 resistance, we cloned the human RAD51 gene, transfected SCLC...... cells with RAD51 sense or antisense constructs and measured the VP16 resistance. Finally, we measured VP16-induced DSBs in the 17 SCLC cell lines. Two cell lines exhibited a multidrug-resistant phenotype. In the other SCLC cell lines, the cellular VP16 resistance was positively correlated with the RAD51...

  10. Regulation of homologous recombination repair protein Rad51 by Ku70

    International Nuclear Information System (INIS)

    Du Liqing; Liu Qiang; Wang Yan; Xu Chang; Cao Jia; Fu Yue; Chen Fenghua; Fan Feiyue

    2013-01-01

    Objective: To explore the regulative effect of non-homologous end joining (NHEJ)protein Ku70 on homologous recombination repair protein Rad51, and to investigate the synergistic mechanism of homologous recombination repair in combination with NHEJ. Methods: Observed Rad51 protein expression after transfect Ku70 small interfering RNA or Ku70 plasmid DNA into tumor cells using Western blot. Results: Expression of Rad51 was obviously reduced after pretreated with Ku70 small interfering RNA. And with the increasing expression of Ku70 protein after transfection of Ku70 plasmid DNA PGCsi3.0-hKu70 into tumor cell lines, the Rad51 protein expression was increased. Conclusion: Ku70 protein has regulating effect on gene expression of Rad51, and it might participate in the collaboration between homologous recombination repair and NHEJ. (authors)

  11. FBH1 helicase disrupts RAD51 filaments in vitro and modulates homologous recombination in mammalian cells

    DEFF Research Database (Denmark)

    Simandlova, Jitka; Zagelbaum, Jennifer; Payne, Miranda J

    2013-01-01

    Efficient repair of DNA double strand breaks and interstrand cross-links requires the homologous recombination (HR) pathway, a potentially error-free process that utilizes a homologous sequence as a repair template. A key player in HR is RAD51, the eukaryotic ortholog of bacterial RecA protein. RAD......51 can polymerize on DNA to form a nucleoprotein filament that facilitates both the search for the homologous DNA sequences and the subsequent DNA strand invasion required to initiate HR. Because of its pivotal role in HR, RAD51 is subject to numerous positive and negative regulatory influences...... filaments on DNA through its ssDNA translocase function. Consistent with this, a mutant mouse embryonic stem cell line with a deletion in the FBH1 helicase domain fails to limit RAD51 chromatin association and shows hyper-recombination. Our data are consistent with FBH1 restraining RAD51 DNA binding under...

  12. MRI for the assessment of malignancy in BI-RADS 4 mammographic microcalcifications.

    Directory of Open Access Journals (Sweden)

    Barbara Bennani-Baiti

    Full Text Available Assess the performance of breast MRI to diagnose breast cancer in BI-RADS 4 microcalcifications detected by mammography.This retrospective, IRB-approved study included 248 consecutive contrast-enhanced breast MRI (1.5T, protocol in accordance with EUSOBI recommendations performed to further diagnose BI-RADS 4 microcalcifications detected at mammography during a 3-year period. Standard of reference had to be established by histopathology. Routine consensus reading results by two radiologists were dichotomized as positive or negative and compared with the reference standard (benign vs malignant to calculate diagnostic parameters.There were 107 malignant and 141 benign microcalcifications. Malignancy rates were 18.3% (23/126 BI-RADS 4a, 41.7% (25/60 BI-RADS 4b and 95% (59/62 BI-RADS 4c. There were 103 true-positive, 116 true-negative, 25 false-positive, and 4 false-negative (one invasive cancer, three DCIS; 2 BI-RADS 4c, 1 BI-RADS 4b on mammography breast MRI findings, effecting a sensitivity, specificity, PPV, and NPV of 96.3% (95%-CI 90.7-99.0%, 82.3% (95%-CI 75.0-88.2%, 80.5% (95%-CI 72.5-87.0% and 96.7% (95%-CI 91.7-99.1%, respectively.MRI is an accurate tool to further diagnose BI-RADS 4a and 4b microcalcifications and may be helpful to avoid unnecessary biopsies in BI-RADS 4a and 4b lesions. BI-RADS 4c microcalcifications should be biopsied irrespective of MRI findings.

  13. Effect of chromic γ-irradiation with small doses on candidiasis development in white rats

    International Nuclear Information System (INIS)

    Berchev, K.; Krushkov, Iv.

    1976-01-01

    Rats continuously exposed to 2 rads/day during eight months (cumulative dose of 400 rads) and nonirradiated rats were infected with a candida cells administered intravenously. All the irradiated animals died ten days after infection while only ten per cent of the control animals died for the same period of time. A morphological study has revealed candidiasis in the irradiated rats; changes, mainly in the kidneys, and formation of candidiasis granulomas have been detected in the control animals

  14. Structure of human Rad51 protein filament from molecular modeling and site-specific linear dichroism spectroscopy

    KAUST Repository

    Reymer, A.; Frykholm, K.; Morimatsu, K.; Takahashi, M.; Norden, B.

    2009-01-01

    for central and N-terminal parts of pure (uncomplexed) Rad51 protein by aid of linear dichroism spectroscopy, providing angular orientations of substituted tyrosine residues of Rad51-dsDNA filaments in solution. The structure, validated by comparison

  15. HiRadMat at CERN/SPS - A dedicated facility providing high intensity beam pulses to material samples

    CERN Multimedia

    Charitonidis, N; Efthymiopoulos, I

    2014-01-01

    HiRadMat (High Radiation to Materials), constructed in 2011, is a facility at CERN designed to provide high‐intensity pulsed beams to an irradiation area where material samples as well as accelerator component assemblies (e.g. vacuum windows, high power beam targets, collimators…) can be tested. The facility uses a 440 GeV proton beam extracted from the CERN SPS with a pulse length of up to 7.2 us, and with a maximum pulse energy of 3.4 MJ (3xE13 proton/pulse). In addition to protons, ion beams with energy of 440 GeV/charge and total pulse energy of 21 kJ can be provided. The beam parameters can be tuned to match the needs of each experiment. HiRadMat is not an irradiation facility where large doses on equipment can be accumulated. It is rather a test area designed to perform single pulse experiments to evaluate the effect of high‐intensity pulsed beams on materials or accelerator component assemblies in a controlled environment. The fa‐ cility is designed for a maximum of 1E16 protons per year, dist...

  16. Determination of radon concentration in water using RAD7 with RAD H{sub 2}O accessories

    Energy Technology Data Exchange (ETDEWEB)

    Malik, M. F. I. [Science and Engineering Research Centre (SERC), Universiti Sains Malaysia, Seri Ampangan Nibong Tebal 14300 Penang (Malaysia); Rabaiee, N. A.; Jaafar, M. S. [School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia)

    2015-04-24

    In the last decade, the radon issue has become one of the major problems of radiation protection. Radon exposure occurs when using water for showering, washing dishes, cooking and drinking water. RAD7 and Rad H20 accessories were used in order to measure radon concentration in water sample. In this study, four types of water were concerns which are reverse osmosis (drinking water), mineral water, tap water and well water. Reverse osmosis (drinking water) and mineral water were bought from the nearest supermarket while tap water and well water were taken from selected areas of Pulau Pinang and Kedah. Total 20 samples were taken with 5 samples for each type of water. The measured radon concentration ranged from 2.9±2.9 to 79.5±17 pCi/L, 2.9±2.9 to 67.8±16 pCi/L, 15.97±7 to 144.25±24 pCi/L and 374.89±37 to 6409.03±130 pCi/L in reverse osmosis (drinking water), mineral water, tap water and well water. Well water has the highest radon compared to others. It was due to their geological element such as granite. Results for all types of water are presented and compared with maximum contamination limit (MCL) recommended by United State Environmental Protection Agency (USEPA) which is 300pCi/L. Reverse osmosis water, mineral water and tap water were fall below MCL. However, well water was exceeded maximum level that was recommended. Thus, these findings were suggested that an action should be taken to reduce radon concentration level in well water as well as reduce a health risk towards the public.

  17. RAD51C germline mutations in breast and ovarian cancer cases from high-risk families.

    Directory of Open Access Journals (Sweden)

    Jessica Clague

    Full Text Available BRCA1 and BRCA2 are the most well-known breast cancer susceptibility genes. Additional genes involved in DNA repair have been identified as predisposing to breast cancer. One such gene, RAD51C, is essential for homologous recombination repair. Several likely pathogenic RAD51C mutations have been identified in BRCA1- and BRCA2-negative breast and ovarian cancer families. We performed complete sequencing of RAD51C in germline DNA of 286 female breast and/or ovarian cancer cases with a family history of breast and ovarian cancers, who had previously tested negative for mutations in BRCA1 and BRCA2. We screened 133 breast cancer cases, 119 ovarian cancer cases, and 34 with both breast and ovarian cancers. Fifteen DNA sequence variants were identified; including four intronic, one 5' UTR, one promoter, three synonymous, and six non-synonymous variants. None were truncating. The in-silico SIFT and Polyphen programs were used to predict possible pathogenicity of the six non-synonomous variants based on sequence conservation. G153D and T287A were predicted to be likely pathogenic. Two additional variants, A126T and R214C alter amino acids in important domains of the protein such that they could be pathogenic. Two-hybrid screening and immunoblot analyses were performed to assess the functionality of these four non-synonomous variants in yeast. The RAD51C-G153D protein displayed no detectable interaction with either XRCC3 or RAD51B, and RAD51C-R214C displayed significantly decreased interaction with both XRCC3 and RAD51B (p<0.001. Immunoblots of RAD51C-Gal4 activation domain fusion peptides showed protein levels of RAD51C-G153D and RAD51C-R214C that were 50% and 60% of the wild-type, respectively. Based on these data, the RAD51C-G153D variant is likely to be pathogenic, while the RAD51C- R214C variant is hypomorphic of uncertain pathogenicity. These results provide further support that RAD51C is a rare breast and ovarian cancer susceptibility gene.

  18. Low-dose radiation as an environmental agent affecting intrauterine development

    International Nuclear Information System (INIS)

    Kameyama, Yoshiro

    1982-01-01

    The low-dose radiation effects which have been recognized in mammalian teratological studies are direct injuries to the particularly radiosensitive tissues of embryo and fetus, and increased incidences of spontaneous malformations and minor anomalies. The lowest radiation doses for manifestation of those effects in mice and rats are: 5 rad for resorption of preimplantation embryos; 5-10 rad for acute cytological changes such as pyknosis, cytoplasmic degeneration and mitotic delay; 5 rad for increasing frequency of spontaneous minor anomalies of the skeleton; 15-20 rad for malformations of the eye, brain and spinal cord; 20-25 rad for histogenetic and functional disorders of the central nervous system; and 20-25 rad for impaired fertility. Pregnant women who are subject to X-ray examination are much concerned about potential hazard of radiation to their offspring in utero. The above experimental findings suggest that the possibility of teratogenic effects of diagnostic radiation on human embryos and fetuses is extremely low, and probably negligible, given the proper dose control measures. (author)

  19. Rad51C deficiency destabilizes XRCC3, impairs recombination and radiosensitizes S/G2-phase cells

    Energy Technology Data Exchange (ETDEWEB)

    Lio, Yi-Ching; Schild, David; Brenneman, Mark A.; Redpath, J. Leslie; Chen, David J.

    2004-05-01

    The highly conserved Rad51 protein plays an essential role in repairing DNA damage through homologous recombination. In vertebrates, five Rad51 paralogs (Rad51B, Rad51C, Rad51D, XRCC2, XRCC3) are expressed in mitotically growing cells, and are thought to play mediating roles in homologous recombination, though their precise functions remain unclear. Here we report the use of RNA interference to deplete expression of Rad51C protein in human HT1080 and HeLa cells. In HT1080 cells, depletion of Rad51C by small interfering RNA caused a significant reduction of frequency in homologous recombination. The level of XRCC3 protein was also sharply reduced in Rad51C-depleted HeLa cells, suggesting that XRCC3 is dependent for its stability upon heterodimerization with Rad51C. In addition, Rad51C-depleted HeLa cells showed hypersensitivity to the DNA cross-linking agent mitomycin C, and moderately increased sensitivity to ionizing radiation. Importantly, the radiosensitivity of Rad51C-deficient HeLa cells was evident in S and G{sub 2}/M phases of the cell cycle but not in G{sub 1} phase. Together, these results provide direct cellular evidence for the importance of human Rad51C in homologous recombinational repair.

  20. The Molecular Basis of Double-Strand DNA Break Repair: The Critical Structure of the RAD52/RPA Complex

    National Research Council Canada - National Science Library

    Jackson, Dobra

    2001-01-01

    .... RAD52 has specific interactions with RAD51, RPA and DNA (1,2,3). The binding of RAD52 to ends of double-strand breaks has been found to be a key initiation step to DNA repair by homologous recombination...

  1. The response of mammalian cells to UV-light reveals Rad54-dependent and independent pathways of homologous recombination

    DEFF Research Database (Denmark)

    Eppink, Berina; Tafel, Agnieszka A; Hanada, Katsuhiro

    2011-01-01

    with lesions in replicating DNA. The core HR protein in mammalian cells is the strand exchange protein RAD51, which is aided by numerous proteins, including RAD54. We used RAD54 as a cellular marker for HR to study the response of mammalian embryonic stem (ES) cells to UV irradiation. In contrast to yeast, ES...

  2. Lysine residue 185 of Rad1 is a topological but not a functional counterpart of lysine residue 164 of PCNA.

    Directory of Open Access Journals (Sweden)

    Niek Wit

    Full Text Available Monoubiquitylation of the homotrimeric DNA sliding clamp PCNA at lysine residue 164 (PCNA(K164 is a highly conserved, DNA damage-inducible process that is mediated by the E2/E3 complex Rad6/Rad18. This ubiquitylation event recruits translesion synthesis (TLS polymerases capable of replicating across damaged DNA templates. Besides PCNA, the Rad6/Rad18 complex was recently shown in yeast to ubiquitylate also 9-1-1, a heterotrimeric DNA sliding clamp composed of Rad9, Rad1, and Hus1 in a DNA damage-inducible manner. Based on the highly similar crystal structures of PCNA and 9-1-1, K185 of Rad1 (Rad1(K185 was identified as the only topological equivalent of PCNA(K164. To investigate a potential role of posttranslational modifications of Rad1(K185 in DNA damage management, we here generated a mouse model with a conditional deletable Rad1(K185R allele. The Rad1(K185 residue was found to be dispensable for Chk1 activation, DNA damage survival, and class switch recombination of immunoglobulin genes as well as recruitment of TLS polymerases during somatic hypermutation of immunoglobulin genes. Our data indicate that Rad1(K185 is not a functional counterpart of PCNA(K164.

  3. The Smc5-Smc6 complex and SUMO modification of Rad52 regulates recombinational repair at the ribosomal gene locus

    DEFF Research Database (Denmark)

    Torres-Rosell, Jordi; Sunjevaric, Ivana; De Piccoli, Giacomo

    2007-01-01

    at an extranucleolar site. The nucleolar exclusion of Rad52 recombination foci entails Mre11 and Smc5-Smc6 complexes and depends on Rad52 SUMO (small ubiquitin-related modifier) modification. Remarkably, mutations that abrogate these activities result in the formation of Rad52 foci within the nucleolus and cause r...

  4. Role of teh Rad52 Amino-terminal DNA Binding Activity in DNA Strand Capture in Homologous Recombination

    DEFF Research Database (Denmark)

    Shi, Idina; Hallwyl, Swee Chuang Lim; Seong, Changhyun

    2009-01-01

    Saccharomyces cerevisiae Rad52 protein promotes homologous recombination by nucleating the Rad51 recombinase onto replication protein A-coated single-stranded DNA strands and also by directly annealing such strands. We show that the purified rad52-R70A mutant protein, with a compromised amino-ter...

  5. Magnetic properties of U(Ni1-xCux)2Si2 solid solutions in the vicinity of x = 0.50 studied by neutron diffraction and AC-susceptibility

    International Nuclear Information System (INIS)

    Kuznietz, M.; Andre, G.; Bouree, F.; Pinto, H.; Ettedgui, H.; Melamud, M.

    1993-01-01

    The magnetic properties of two U(Ni 1-x Cu x ) 2 Si 2 solid in the vicinity of x = 0.50 (denoted I and II) have been studied by neutron diffraction and ac-susceptibility. Both materials have ThCr 2 Si 2 -type crystallographic structure. AC-susceptibility shows antiferromagnetic transitions at T N 150±5 K in UNiCuSi 2 (I) and 155±5 K in UNiCuSi 2 (II), followed by several transitions with ferrimagnetic (F) character at lower temperatures. Apart from the transitions to AF-I structure at T N =150K and 152K none of the F transitions is observed by neutron diffraction. Short-range magnetic order, involving several consecutive ferromagnetic planes or ferrimagnetic groups of planes in the AF-I phase, detected by ac-susceptibility and not by neutron diffraction in both materials and therefore significant to x ∼ 0.50, is proposed to explain the unusual susceptibility. (Author)

  6. Radiation doses from residual radioactivity

    International Nuclear Information System (INIS)

    Okajima, Shunzo; Fujita, Shoichiro; Harley, John H.

    1987-01-01

    requires knowing the location of the person to within about 200 m from the time of the explosion to a few weeks afterwards. This is an effort that might be comparable to the present shielding study for survivors. The sizes of the four exposed groups are relatively small; however, the number has been estimated only for those exposed to fallout in the Nishiyama district of Nagasaki. Okajima listed the population of Nishiyama as about 600 at the time of the bomb. No figures are available for the other three groups. The individual exposures from residual radiation may not be significant compared with the direct radiation at the time of the bomb. On the other hand, individuals with potential exposure from these sources are dubious candidates for inclusion in a cohort that was presumably not exposed. For comparison with organ doses estimated in other parts of this program, the exposure estimates are converted to absorbed dose in tissue. The first conversion of exposure to absorbed dose in air uses the factor rad in air 0.87 x exposure in R. UNSCEAR uses an average combined factor of 0.7 to convert absorbed dose in air to absorbed dose in tissue for the whole body. This factor accounts for the change in material (air to tissue) and for backscatter and the shielding afforded by other tissues of the body. No allowance for shielding by buildings has been included here. The cumulative fallout exposures given above become absorbed doses in tissue of 12 to 24 rad for Nagasaki and 0.6 to 2 rad for Hiroshima. The cumulative exposures from induced radioactivity become absorbed doses in tissue of 18 to 24 rad for Nagasaki and about 50 rad for Hiroshima. (author)

  7. Rad51 expression levels predict synthetic lethality and metastatic potential in high grade breast cancers

    International Nuclear Information System (INIS)

    Wiegmans, A.P.; Al-Ejeh, F.; Khanna, K.K.

    2012-01-01

    Among women with breast cancer, 30-40% will develop metastatic disease and only achieve an overall survival of less than 5 years. Despite new-targeted therapy, breast tumors that harbour similar histology or molecular phenotype differ in their response to treatment. To uncover potential new therapeutic targets and improve outcome, we performed data mining of cancer micro array databases. We found that high expression of the homologous recombination protein, RAD51, was significantly associated with high-grade breast cancer, aggressive subtypes and increased risk of metastasis. We confirmed using immunohistochemistry that RAD5 1 was highly expressed in metastatic tumours and high-grade triple negative, HER2+ and luminal-B tumours. This provided a rationale for targeting RAD5 1 in high-grade, therapy-resistant breast cancers. Here, we report for the first time preclinical evaluation of RAD5 1 as a therapeutic target. We found that, in-vitro high RAD5 expressing cell lines were resistant to PARP inhibitor while knockdown reversed this resistance. In-vivo, knockdown of RAD5 1 inhibited metastatic progression using a syngeneic breast cancer model and the seeding of human xenografts to distant sites, including brain and lung. Concurrent PARP inhibition reduced primary tumor growth and delayed metastasis supporting synthetic lethality in-vivo. Together these insights provide pre-clinical data demonstrating RAD5 1 as a new biomarker and potential therapeutic target against aggressive metastatic breast cancer. (author)

  8. Structure of a hexameric form of RadA recombinase from Methanococcus voltae

    International Nuclear Information System (INIS)

    Du, Liqin; Luo, Yu

    2012-01-01

    Hexameric rings of RadA recombinase from M. voltae have been crystallized. Structural comparisons suggest that homologues of RadA tend to form double-ringed assemblies. Archaeal RadA proteins are close homologues of eukaryal Rad51 and DMC1 proteins and are remote homologues of bacterial RecA proteins. For the repair of double-stranded breaks in DNA, these recombinases promote a pivotal strand-exchange reaction between homologous single-stranded and double-stranded DNA substrates. This DNA-repair function also plays a key role in the resistance of cancer cells to chemotherapy and radiotherapy and in the resistance of bacterial cells to antibiotics. A hexameric form of a truncated Methanococcus voltae RadA protein devoid of its small N-terminal domain has been crystallized. The RadA hexamers further assemble into two-ringed assemblies. Similar assemblies can be observed in the crystals of Pyrococcus furiosus RadA and Homo sapiens DMC1. In all of these two-ringed assemblies the DNA-interacting L1 region of each protomer points inward towards the centre, creating a highly positively charged locus. The electrostatic characteristics of the central channels can be utilized in the design of novel recombinase inhibitors

  9. Differential hRad17 expression by histologic subtype of ovarian cancer

    Directory of Open Access Journals (Sweden)

    Young Jennifer L

    2011-03-01

    Full Text Available Abstract Background In the search for unique ovarian cancer biomarkers, ovarian specific cDNA microarray analysis identified hRad17, a cell cycle checkpoint protein, as over-expressed in ovarian cancer. The aim of this study was to validate this expression. Methods Immunohistochemistry was performed on 72 serous, 19 endometrioid, 10 clear cell, and 6 mucinous ovarian cancers, 9 benign ovarian tumors, and 6 normal ovarian tissue sections using an anti-hRad17 antibody. Western blot analysis and quantitative PCR were performed using cell lysates and total RNA prepared from 17 ovarian cancer cell lines and 6 normal ovarian epithelial cell cultures (HOSE. Results Antibody staining confirmed upregulation of hRad17 in 49.5% of ovarian cancer cases. Immunohistochemistry demonstrated that only 42% of serous and 47% of endometrioid subtypes showed overexpression compared to 80% of clear cell and 100% of mucinous cancers. Western blot confirmed overexpression of hRad17 in cancer cell lines compared to HOSE. Quantitative PCR demonstrated an upregulation of hRad17 RNA by 1.5-7 fold. hRad17 RNA expression differed by subtype. Conclusions hRad17 is over-expressed in ovarian cancer. This over-expression varies by subtype suggesting a role in the pathogenesis of these types. Functional studies are needed to determine the potential role of this protein in ovarian cancer.

  10. Mediator links transcription and DNA repair by facilitating Rad2/XPG recruitment.

    Science.gov (United States)

    Eyboulet, Fanny; Cibot, Camille; Eychenne, Thomas; Neil, Helen; Alibert, Olivier; Werner, Michel; Soutourina, Julie

    2013-12-01

    Mediator is a large multiprotein complex conserved in all eukaryotes. The crucial function of Mediator in transcription is now largely established. However, we found that this complex also plays an important role by connecting transcription with DNA repair. We identified a functional contact between the Med17 Mediator subunit and Rad2/XPG, the 3' endonuclease involved in nucleotide excision DNA repair. Genome-wide location analyses revealed that Rad2 is associated with RNA polymerase II (Pol II)- and Pol III-transcribed genes and telomeric regions in the absence of exogenous genotoxic stress. Rad2 occupancy of Pol II-transcribed genes is transcription-dependent. Genome-wide Rad2 occupancy of class II gene promoters is well correlated with that of Mediator. Furthermore, UV sensitivity of med17 mutants is correlated with reduced Rad2 occupancy of class II genes and concomitant decrease of Mediator interaction with Rad2 protein. Our results suggest that Mediator is involved in DNA repair by facilitating Rad2 recruitment to transcribed genes.

  11. Necessary accuracy of dose estimation during cohort epidemiologic study after irradiation

    International Nuclear Information System (INIS)

    Orlov, M.Yu.; Stepanenko, V.F.; Khoshi, M.; Takada, Dzh.

    2003-01-01

    Effect of breadth of dose ranges on values of radiation risk was estimated. Ratios of observed numbers of mortalities because of leukemia in the cohort in 1950 - 1974 under deferent radiation dose to expected number of mortalities in this cohort only under background radiation were used as degree of risk. Data of cooperative Japan-American Program LSS (Life Span Study) were applied in the researches. It is established that required for the risk assessment with uncertainty 20 - 30 % the accuracy of dose estimation comprises 30 - 35 % in the range 1 - 5 rad and 5 - 10 % in the range 5 - 30 rad [ru

  12. Evaluations of gonad and fetal doses for diagnostic radiology.

    Science.gov (United States)

    Tung, C J; Tsai, H Y

    1999-07-01

    A national survey of patient doses for diagnostic radiology was planned in the Republic of China. We performed a pilot study for this survey to develop a protocol of the dose assessments. Entrance skin doses and organ (including ovary, testicle and uterus) doses were measured by thermoluminescent dosimeters and calculated by means of Monte Carlo simulations for several diagnostic procedures. We derived a formula and used the RadComp software for the computation of entrance skin doses. This formula involves several factors, such as kVp, mAs, the focus-to-skin-distance and aluminum filtration. RadComp software was applied to obtain free-air entrance exposures which were converted to entrance skin doses by considering the backscattering radiation from the body. Organ doses were measured using a RANDO phantom and calculated using a mathematical phantom for several diagnostic examinations. Genetically significant doses were calculated from ovary and testicle doses for the evaluation of hereditary effects. Embryo/fetal doses were determined from the uterine doses by considering the increase in uterus size with gestational age. We found that the patient doses studied in this work were all below the reference doses recommended by the National Radiological Protection Board of the U.K.

  13. Comparison of Danish dichotomous and BI-RADS classifications of mammographic density.

    Science.gov (United States)

    Hodge, Rebecca; Hellmann, Sophie Sell; von Euler-Chelpin, My; Vejborg, Ilse; Andersen, Zorana Jovanovic

    2014-06-01

    In the Copenhagen mammography screening program from 1991 to 2001, mammographic density was classified either as fatty or mixed/dense. This dichotomous mammographic density classification system is unique internationally, and has not been validated before. To compare the Danish dichotomous mammographic density classification system from 1991 to 2001 with the density BI-RADS classifications, in an attempt to validate the Danish classification system. The study sample consisted of 120 mammograms taken in Copenhagen in 1991-2001, which tested false positive, and which were in 2012 re-assessed and classified according to the BI-RADS classification system. We calculated inter-rater agreement between the Danish dichotomous mammographic classification as fatty or mixed/dense and the four-level BI-RADS classification by the linear weighted Kappa statistic. Of the 120 women, 32 (26.7%) were classified as having fatty and 88 (73.3%) as mixed/dense mammographic density, according to Danish dichotomous classification. According to BI-RADS density classification, 12 (10.0%) women were classified as having predominantly fatty (BI-RADS code 1), 46 (38.3%) as having scattered fibroglandular (BI-RADS code 2), 57 (47.5%) as having heterogeneously dense (BI-RADS 3), and five (4.2%) as having extremely dense (BI-RADS code 4) mammographic density. The inter-rater variability assessed by weighted kappa statistic showed a substantial agreement (0.75). The dichotomous mammographic density classification system utilized in early years of Copenhagen's mammographic screening program (1991-2001) agreed well with the BI-RADS density classification system.

  14. Protein dynamics of human RPA and RAD51 on ssDNA during assembly and disassembly of the RAD51 filament.

    Science.gov (United States)

    Ma, Chu Jian; Gibb, Bryan; Kwon, YoungHo; Sung, Patrick; Greene, Eric C

    2017-01-25

    Homologous recombination (HR) is a crucial pathway for double-stranded DNA break (DSB) repair. During the early stages of HR, the newly generated DSB ends are processed to yield long single-stranded DNA (ssDNA) overhangs, which are quickly bound by replication protein A (RPA). RPA is then replaced by the DNA recombinase Rad51, which forms extended helical filaments on the ssDNA. The resulting nucleoprotein filament, known as the presynaptic complex, is responsible for pairing the ssDNA with homologous double-stranded DNA (dsDNA), which serves as the template to guide DSB repair. Here, we use single-molecule imaging to visualize the interplay between human RPA (hRPA) and human RAD51 during presynaptic complex assembly and disassembly. We demonstrate that ssDNA-bound hRPA can undergo facilitated exchange, enabling hRPA to undergo rapid exchange between free and ssDNA-bound states only when free hRPA is present in solution. Our results also indicate that the presence of free hRPA inhibits RAD51 filament nucleation, but has a lesser impact upon filament elongation. This finding suggests that hRPA exerts important regulatory influence over RAD51 and may in turn affect the properties of the assembled RAD51 filament. These experiments provide an important basis for further investigations into the regulation of human presynaptic complex assembly. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  15. Non-targeted effects of ionising radiation. Proceedings of the RISC-RAD specialised training course

    International Nuclear Information System (INIS)

    Belyakov, O.V.

    2008-12-01

    The training course 'Non-targeted effects of ionising radiation' took place at the STUK, Radiation and Nuclear Safety Authority, Helsinki, Finland 14-16 February 2005. Proceeding of this course is collected in this volume. The idea of the course was to convene a number of scientists leading in the area of non-targeted effects of ionising radiation with the aim to outline their visions for the role of these effects and outline the future directions of radiation research on the basis of their expertise. The course was supported by the RISC-RAD IP FI6R-CT-2003-508842, Euratom specific programme for research and training on nuclear energy, 6th FP of the EC. The main objectives of the training course were: (1) to clarify the mechanisms of non-targeted effects, in particular, bystander effects, genomic instability and adaptive response; (2) to look if and how non-targeted effects modulate the cancer risk in the low dose region, and whether they relate to protective or harmful functions; (3) to clarify if ionising radiation can cause non-cancer diseases or beneficial effects at low and intermediate doses; (4) address the issue of individual susceptibility and other factors modifying non-targeted responses; (5) attempt to assess the relevance of non-targeted effects for radiation protection and to set the scientific basis for a modern, more realistic, radiation safety system; (6) and finally to contribute to the conceptualisation of a new paradigm in radiation biology that would cover both the classical direct (DNA-targeted) and non-targeted (indirect) effects

  16. Yugoslav central disposal system or rad waste materials: necessity and justification of construction

    International Nuclear Information System (INIS)

    Peric, A.; Plecas, I.; Pavlovic, R.

    1995-01-01

    Decision on searching for the location and the choice of appropriate type of system for final disposal of low and intermediate level rad waste materials should be made urgently in Yugoslavia. capacities for further storing of such waste materials on the site of the Vinca Institute will be full in the next few years, following the trend of present rad waste generation and delivery. Selection of the location and type of the disposal system in Yugoslavia is of crucial importance from the point of view of conservation of environment quality level and enabling permanent control of disposed immobilized rad waste materials and its impact on the environment. (author)

  17. Effects of oxygen and TMPN on the initial part of the dose-effect curves of human cells in culture

    International Nuclear Information System (INIS)

    Pettersen, E.O.; Wibe, E.; Lovhaug, D.; Oftebro, R.; Brustad, T.

    1975-01-01

    Human cells of the established cell line NHIK 3025 have been irradiated under various conditions of oxygen and TMPN concentrations. Complete survival curves are presented for each concentration of both oxygen and TMPN. The survival curves for extremely hypoxic cells in the absence of TMPN were found to be strictly exponential in the dose range below about 2300 rad, irrespective of the technique used. Oxygen at a concentration of 37 ppm was found to protect the cells at least above the dose range up to 2500 rad, while 250 ppm of oxygen exerted a protective effect in the dose range below 1200 rad and a sensitizing effect (OER = 1.43) for higher doses. However, the protective effect below 700 rad was found to be higher in the presence of 250 ppm O 2 , than 37 ppm O 2 , indicating that the degree of protection in this low-dose range is optimal for an oxygen concentration higher than 37 ppm. TMPN provides a protective and a sensitizing effect in about the same way as oxygen does, but TMPN is less effective. When the TMPN concentration is increased from 0.5 to 10 mM the maximum dose for which TMPN exerts a protective effect on the hypoxic cells decreases from 700 to 400 rad. However the degree of protection in the dose range below 300 rad is higher for TMPN concentrations of 1 mM and 3 mM than for 0.5 mM and 10 mM. Results indicate that the degree of protection is optimal in the low-dose range (< 300 rad) for a TMPN concentration somewhere between 0.5 mM and 3 mM. (author)

  18. Doses in radiation accidents investigated by chromosome aberration analysis

    International Nuclear Information System (INIS)

    Lloyd, D.C.; Purrott, R.J.; Prosser, J.S.; White, A.D.; Hesketh, L.C.; Priseman, S.J.; Lelliot, D.J.; Stimpson, L.W.

    1980-02-01

    The results are reviewed from investigations during 1979 into 82 cases of suspected over-exposure to radiation. Of these 45 were associated with industrial radiography, 11 with one or other of the major nuclear organisations, and 26 with an institution of research, education or health. 83% of the dose estimates were in the range 0.0-0.09 Gy (0-9 rad), and 17% in the range 0.1-0.29 Gy (10-29 rad). These data are compared with data obtained by physical dosimetry, and a brief summary is given of the circumstances of each over-exposure, or suspected over-exposure. (author)

  19. RBE/absorbed dose relationship of d(50)-Be neutrons determined for early intestinal tolerance in mice

    International Nuclear Information System (INIS)

    Gueulette, J.; Wambersie, A.

    1978-01-01

    RBE/absorbed dose relationship of d(50)-Be neutrons (ref.: 60 Co) was determined using intestinal tolerance in mice (LD50) after single and fractionated irradiation. RBE is 1.8 for a single fraction (about 1000 rad 60 Co dose); it increases when decreasing dose and reaches the plateau value of 2.8 for a 60 Co dose of about 200 rad. This RBE value is used for the clinical applications with the cyclotron 'Cyclone' at Louvain-la-Neuve [fr

  20. Radiation dose distributions close to the shower axis calculated for high energy electron initiated electromagnetic showers in air

    International Nuclear Information System (INIS)

    Geer, S.; Gsponer, A.

    1983-01-01

    Absorbed radiation doses produced by 500, 1,000 and 10,000 MeV electron initiated electromagnetic showers in air have been calculated using a Monte Carlo program. The radial distributions of the absorbed dose near to the shower axis are found to be significantly narrower than predicted by simple analytical shower theory. For a 500 MeV, 10 kA, 100 ns electron beam pulse, the region in which the total dose is in excess of 1 krad and the dose rate in excess of 10 10 rad/s is a cigar-shaped envelope of radius 1 m and length 200 m. (orig.) [de

  1. Absorbed dose thresholds and absorbed dose rate limitations for studies of electron radiation effects on polyetherimides

    Science.gov (United States)

    Long, Edward R., Jr.; Long, Sheila Ann T.; Gray, Stephanie L.; Collins, William D.

    1989-01-01

    The threshold values of total absorbed dose for causing changes in tensile properties of a polyetherimide film and the limitations of the absorbed dose rate for accelerated-exposure evaluation of the effects of electron radiation in geosynchronous orbit were studied. Total absorbed doses from 1 kGy to 100 MGy and absorbed dose rates from 0.01 MGy/hr to 100 MGy/hr were investigated, where 1 Gy equals 100 rads. Total doses less than 2.5 MGy did not significantly change the tensile properties of the film whereas doses higher than 2.5 MGy significantly reduced elongation-to-failure. There was no measurable effect of the dose rate on the tensile properties for accelerated electron exposures.

  2. Bible and Philology: Gerhard von Rad regarding the Wisdom Books

    Directory of Open Access Journals (Sweden)

    Norma Haydeé Lase

    2015-04-01

    Full Text Available Theology, through its history, has always been related to Philology, because its source is the Holy Scriptures. This reason has stimulated my further consideration of the exegeta Gerhard von Rad “Wisdom in Israel” a “symbol” of modern interest for the Wisdom books. Inserted in the philologic German trend of the history of tradition and history of editing and forms, it is opposed to positivists interpretation and installs a new comprehension of the OT traditions. Its hermeneutica, without deteriorating the historical criticism, gives first hand priority to the message that the scriptural brands patentize as a twist of an organization in constant growth. However, the love of live words, which is considered by the philologist, make him capable to have a wide effect of the methodological tools, and in this way; unravel the secrets of the world of wisdom. Now in the threshold of Christianism, Wisdom books prepare the adequate opening to receive the “new Wine” in “new containers”. Also, today, philology and wisdom summon us to go along with this moment of the History of Salvation with the necessary instruments and ancient breeding by old and modern wisemen.

  3. Mammogram retrieval through machine learning within BI-RADS standards.

    Science.gov (United States)

    Wei, Chia-Hung; Li, Yue; Huang, Pai Jung

    2011-08-01

    A content-based mammogram retrieval system can support usual comparisons made on images by physicians, answering similarity queries over images stored in the database. The importance of searching for similar mammograms lies in the fact that physicians usually try to recall similar cases by seeking images that are pathologically similar to a given image. This paper presents a content-based mammogram retrieval system, which employs a query example to search for similar mammograms in the database. In this system the mammographic lesions are interpreted based on their medical characteristics specified in the Breast Imaging Reporting and Data System (BI-RADS) standards. A hierarchical similarity measurement scheme based on a distance weighting function is proposed to model user's perception and maximizes the effectiveness of each feature in a mammographic descriptor. A machine learning approach based on support vector machines and user's relevance feedback is also proposed to analyze the user's information need in order to retrieve target images more accurately. Experimental results demonstrate that the proposed machine learning approach with Radial Basis Function (RBF) kernel function achieves the best performance among all tested ones. Furthermore, the results also show that the proposed learning approach can improve retrieval performance when applied to retrieve mammograms with similar mass and calcification lesions, respectively. Copyright © 2011 Elsevier Inc. All rights reserved.

  4. Dose rate and dose fractionation studies in total body irradiation of dogs

    International Nuclear Information System (INIS)

    Kolb, H.J.; Netzel, B.; Schaffer, E.; Kolb, H.

    1979-01-01

    Total body irradiation (TBI) with 800-900 rads and allogeneic bone marrow transplantation according to the regimen designated by the Seattle group has induced remissions in patients with otherwise refractory acute leukemias. Relapse of leukemia after bone marrow transplantation remains the major problem, when the Seattle set up of two opposing 60 Co-sources and a low dose rate is used in TBI. Studies in dogs with TBI at various dose rates confirmed observations in mice that gastrointestinal toxicity is unlike toxicity against hemopoietic stem cells and possibly also leukemic stem cells depending on the dose rate. However, following very high single doses (2400 R) and marrow infusion acute gastrointestinal toxicity was not prevented by the lowest dose rate studied (0.5 R/min). Fractionated TBI with fractions of 600 R in addition to 1200 R (1000 rads) permitted the application of total doses up to 300 R followed by marrow infusion without irreversible toxicity. 26 dogs given 2400-3000 R have been observed for presently up to 2 years with regard to delayed radiation toxicity. This toxicity was mild in dogs given single doses at a low dose rate or fractionated TBI. Fractionated TBI is presently evaluated with allogeneic transplants in the dog before being applied to leukemic patients

  5. Effects of small radiation doses

    International Nuclear Information System (INIS)

    Fuchs, G.

    1986-01-01

    The term 'small radiation dosis' means doses of about (1 rem), fractions of one rem as well as doses of a few rem. Doses like these are encountered in various practical fields, e.g. in X-ray diagnosis, in the environment and in radiation protection rules. The knowledge about small doses is derived from the same two forces, on which the radiobiology of human beings nearly is based: interpretation of the Hiroshima and Nagasaki data, as well as the experience from radiotherapy. Careful interpretation of Hiroshima dates do not provide any evidence that small doses can induce cancer, fetal malformations or genetic damage. Yet in radiotherapy of various diseases, e.g. inflammations, doses of about 1 Gy (100 rad) do no harm to the patients. According to a widespread hypothesis even very small doses may induce some types of radiation damage ('no threshold'). Nevertheless an alternative view is justified. At present no decision can be made between these two alternatives, but the usefullness of radiology is definitely better established than any damage calculated by theories or extrapolations. Based on experience any exaggerated fear of radiations can be met. (author)

  6. Plutonium dose-effect relationship

    International Nuclear Information System (INIS)

    Matsuoka, Osamu

    1976-01-01

    Dose in internal exposure to Pu was investigated, and dose-effect relationship was discussed. Dose-effect relationship in internal exposure was investigated by means of two methods, which were relationship between dose and its effect (relationship between μ Ci/Kg and its effect), and exposure dose and its effects (rad-effect), and merits and demerits of two methods were mentioned. Problems in a indication method such as mean dose were discussed with respect to the dose in skeleton, the liver and the lung. Pu-induced osteosarcoma in mice rats, and beagles was described, and differences in its induction between animals were discussed. Pulmonary neoplasma induced by 239 PuO 2 inhalation in beagles was reported, and description was made as to differences in induction of lung cancer between animals when Pu was inhaled and was taken into the lung. A theoretical and experimental study of a extrapolation of the results of the animal experiment using Pu to human cases is necessary. (Serizawa, K.)

  7. Rad GTPase is essential for the regulation of bone density and bone marrow adipose tissue in mice.

    Science.gov (United States)

    Withers, Catherine N; Brown, Drew M; Byiringiro, Innocent; Allen, Matthew R; Condon, Keith W; Satin, Jonathan; Andres, Douglas A

    2017-10-01

    The small GTP-binding protein Rad (RRAD, Ras associated with diabetes) is the founding member of the RGK (Rad, Rem, Rem2, and Gem/Kir) family that regulates cardiac voltage-gated Ca 2+ channel function. However, its cellular and physiological functions outside of the heart remain to be elucidated. Here we report that Rad GTPase function is required for normal bone homeostasis in mice, as Rad deletion results in significantly lower bone mass and higher bone marrow adipose tissue (BMAT) levels. Dynamic histomorphometry in vivo and primary calvarial osteoblast assays in vitro demonstrate that bone formation and osteoblast mineralization rates are depressed, while in vitro osteoclast differentiation is increased, in the absence of Rad. Microarray analysis revealed that canonical osteogenic gene expression (Runx2, osterix, etc.) is not altered in Rad -/- calvarial osteoblasts; instead robust up-regulation of matrix Gla protein (MGP, +11-fold), an inhibitor of extracellular matrix mineralization and a protein secreted during adipocyte differentiation, was observed. Strikingly, Rad deficiency also resulted in significantly higher marrow adipose tissue levels in vivo and promoted spontaneous in vitro adipogenesis of primary calvarial osteoblasts. Adipogenic differentiation of wildtype calvarial osteoblasts resulted in the loss of endogenous Rad protein, further supporting a role for Rad in the control of BMAT levels. These findings reveal a novel in vivo function for Rad and establish a role for Rad signaling in the complex physiological control of skeletal homeostasis and bone marrow adiposity. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Effects of low dose rate γ-rays on cell proliferation and survival in exponentially growing and plateau phase cultures of normal rat kidney cells

    International Nuclear Information System (INIS)

    Tsuboi, A.

    1982-01-01

    The effects of 60 Co γ-rays on cell clonogenicity and cell proliferation were examined in NRK cells in exponential and plateau growth phases during and after irradiation at various dose rates. The typical dese rate effect for the survival responses was observed between acute irradiation and continuous irradiation at dose rates of 9.6-44 rads/h. Similar dose rate effect for the perturbation of the proliferation was observed in exponentially growing cells during irradiation. Some differences were found in survival when the cells were exposed to γ-rays at 9.6 rads/h or at 13.7 rads/h. The survival curves of exponential phase cells irradiated at these dose rates showed a shape different from that observed in plateau phase cells. Namely, a steady state of survival appeared around an accumulated dose of 1000 rads (dose-rate of 9.6 rads/h) and an accumulated dose of 1500 rads (dose-rate of 13.7 rads/h) in the exponential phase cells, while such a steady state of survival was not detected in plateau phase cells after similar conditions of irradiation. Moreover, the extrapolation number of the survival curve was much larger at the lower dose rate in exponential phase cells, in contrast to a value of the unity oberved in plateau phase cells, The radiosensitivity of plateau phase cells was somewhat lower compared to exponential phase cells over the range of accumulated doses at the dose rates used. These differences in cellular responses to the radiation between the two phases could be explained by changes in cell proliferation, the redistribution of the cell cycle compartments and the repair capacity of cellular damage during irradiation. (author)

  9. Breast imaging reporting and data system (BI-RADS) lexicon for breast MRI: Interobserver variability in the description and assignment of BI-RADS category

    Energy Technology Data Exchange (ETDEWEB)

    El Khoury, Mona, E-mail: monelkhoury@gmail.com [Centre Hospitalier Universitaire de Montréal, Breast Centre, Radiology Department, 3840 Rue Saint Urbain, Montréal, QC H2W1T8 (Canada); Lalonde, Lucie; David, Julie; Labelle, Maude [Centre Hospitalier Universitaire de Montréal, Breast Centre, Radiology Department, 3840 Rue Saint Urbain, Montréal, QC H2W1T8 (Canada); Mesurolle, Benoit [Centre Hospitalier Universitaire de McGill, Cedar Breast Centre, Radiology Department, 687 Pine Avenue West, Montreal, QC H3A1A1 (Canada); Trop, Isabelle [Centre Hospitalier Universitaire de Montréal, Breast Centre, Radiology Department, 3840 Rue Saint Urbain, Montréal, QC H2W1T8 (Canada)

    2015-01-15

    Highlights: • The use of BI-RADS lexicon in interpreting breast MRI examinations is beneficial. • Our study shows: (a) moderate to substantial agreement between observers and (b) better agreement in interpreting mass than non-mass enhancement (NME). • Careful analysis of the NME should be done to help detect cancer as early as possible. - Abstract: Purpose: To retrospectively evaluate interobserver variability between breast radiologists when describing abnormal enhancement on breast MR examinations and assigning a BI-RADS category using the Breast Imaging Reporting and Data System (BI-RADS) terminology. Materials and methods: Five breast radiologists blinded to patients’ medical history and pathologic results retrospectively and independently reviewed 257 abnormal areas of enhancement on breast MRI performed in 173 women. Each radiologist described the focal enhancement using BI-RADS terminology and assigned a final BI-RADS category. Krippendorff's α coefficient of agreement was used to asses interobserver variability. Results: All radiologists agreed on the morphology of enhancement in 183/257 (71%) lesions, yielding a substantial agreement (Krippendorff's α = 0.71). Moderate agreement was obtained for mass descriptors – shape, margins and internal enhancement – (α = 0.55, 0.51 and 0.45 respectively) and NME (non-mass enhancement) descriptors – distribution and internal enhancement – (α = 0.54 and 0.43). Overall substantial agreement was obtained for BI-RADS category assignment (α = 0.71). It was however only moderate (α = 0.38) for NME compared to mass (α = 0.80). Conclusion: Our study shows good agreement in describing mass and NME on a breast MR examination but a better agreement in predicting malignancy for mass than NME.

  10. Breast imaging reporting and data system (BI-RADS) lexicon for breast MRI: Interobserver variability in the description and assignment of BI-RADS category

    International Nuclear Information System (INIS)

    El Khoury, Mona; Lalonde, Lucie; David, Julie; Labelle, Maude; Mesurolle, Benoit; Trop, Isabelle

    2015-01-01

    Highlights: • The use of BI-RADS lexicon in interpreting breast MRI examinations is beneficial. • Our study shows: (a) moderate to substantial agreement between observers and (b) better agreement in interpreting mass than non-mass enhancement (NME). • Careful analysis of the NME should be done to help detect cancer as early as possible. - Abstract: Purpose: To retrospectively evaluate interobserver variability between breast radiologists when describing abnormal enhancement on breast MR examinations and assigning a BI-RADS category using the Breast Imaging Reporting and Data System (BI-RADS) terminology. Materials and methods: Five breast radiologists blinded to patients’ medical history and pathologic results retrospectively and independently reviewed 257 abnormal areas of enhancement on breast MRI performed in 173 women. Each radiologist described the focal enhancement using BI-RADS terminology and assigned a final BI-RADS category. Krippendorff's α coefficient of agreement was used to asses interobserver variability. Results: All radiologists agreed on the morphology of enhancement in 183/257 (71%) lesions, yielding a substantial agreement (Krippendorff's α = 0.71). Moderate agreement was obtained for mass descriptors – shape, margins and internal enhancement – (α = 0.55, 0.51 and 0.45 respectively) and NME (non-mass enhancement) descriptors – distribution and internal enhancement – (α = 0.54 and 0.43). Overall substantial agreement was obtained for BI-RADS category assignment (α = 0.71). It was however only moderate (α = 0.38) for NME compared to mass (α = 0.80). Conclusion: Our study shows good agreement in describing mass and NME on a breast MR examination but a better agreement in predicting malignancy for mass than NME

  11. Radiation dose estimates for copper-64 citrate in man

    International Nuclear Information System (INIS)

    Crook, J.E.; Carlton, J.E.; Stabin, M.; Watson, E.

    1985-01-01

    Tumor imaging agents suitable for use with positron emission tomographs are constantly sought. We have performed studies with animal-tumor-bearing models that have demonstrated the rapid uptake of copper-64. The radiation dose estimates for man indicate that the intravenous administration of 7.0 mCi would result in radiation doses to the kidney of 9.8 to 10.5 rads with other organs receiving substantially less radiation. 5 refs., 3 tabs

  12. Radiation dose estimates for copper-64 citrate in man

    International Nuclear Information System (INIS)

    Crook, J.E.; Carlton, J.E.; Stabin, M.; Watson, E.

    1986-01-01

    Tumor imaging agents suitable for use with positron emission tomographs are constantly sought. The authors have performed studies with animal-tumor-bearing models that have demonstrated the rapid uptake of copper-64. The radiation dose estimates for man indicate that the intravenous administration of 7.0 mCi would result in radiation doses to the kidney of 9.8 to 10.5 rads with other organs receiving substantially less radiations. 5 references, 3 tables

  13. Estudio dilatométrico de la descomposición anisotérmica de la perlita en un acero bajo en carbono (0,11 C-0,50 Mn

    Directory of Open Access Journals (Sweden)

    García de Andrés, C.

    1998-05-01

    Full Text Available A dilatometric contraction at the onset of the austenitization has been detected by means of high resolution dilatometric analysis. This anomaly was associated with the pearlite dissolution process. A significant effect of pearlite interlamellar spacing on the shape of the dilatometric anomaly has been found. A clear dilatometric anomaly can only be detected when a fine pearlite is present in the starting microstructure of the steel. The identification of the temperature at which pearlite dissolution finishes would make it possible to select the most suitable intercritical temperature to obtain ferrite + martensite dual phase microstructures with an optimum combination of mechanical properties. In the presente work, the influence of starting pearlite morphology on the dilatometric response associated with the pearlite dissolution process during continuous heating has been studied in 0.11C-0.50Mn low carbon steel.

    Por medio del análisis dilatométrico de alta resolución, se ha detectado la aparición de una contracción dilatométrica asociada con el proceso de disolución de la perlita, que únicamente aparece cuando la microestructura inicial presenta perlita con un espaciado interlaminar fino. Esta contracción dilatométrica desaparece cuando la estructura inicial presenta una perlita grosera o de mayor espaciado interlaminar, impidiendo así la selección de las temperaturas del intercrítico más apropiadas para la obtención de microestructuras dual de ferrita + martensita con las mejores propiedades mecánicas. En este trabajo se estudia la influencia de la morfología de la perlita inicial de un acero 0,11C-0,50Mn sobre la respuesta dilatométrica asociada al proceso de disolución de dicha fase en calentamiento continuo.

  14. High-pressure high-temperature stability of hcp-IrxOs1-x (x = 0.50 and 0.55) alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yusenko, Kirill V.; Bykova, Elena; Bykov, Maxim; Gromilov, Sergey A.; Kurnosov, Alexander V.; Prescher, Clemens; Prakapenka, Vitali B.; Crichton, Wilson A.; Hanfland, Michael; Margadonna, Serena; Dubrovinsky, Leonid S.

    2016-12-23

    Hcp-Ir0.55Os0.45 and hcp-Ir0.50Os0.50 alloys were synthesised by thermal decomposition of single-source precursors in hydrogen atmosphere. Both alloys correspond to a miscibility gap in the Ir–Os binary phase diagram and therefore are metastable at ambient conditions. An in situ powder X-ray diffraction has been used for a monitoring a formation of hcp-Ir0.55Os0.45 alloy from (NH4)2[Ir0.55Os0.45Cl6] precursor. A crystalline intermediate compound and nanodimentional metallic particles with a large concentration of defects has been found as key intermediates in the thermal decomposition process in hydrogen flow. High-temperature stability of titled hcp-structured alloys has been investigated upon compression up to 11 GPa using a multi-anvil press and up to 80 GPa using laser-heated diamond-anvil cells to obtain a phase separation into fcc + hcp mixture. Compressibility curves at room temperature as well as thermal expansion at ambient pressure and under compression up to 80 GPa were collected to obtain thermal expansion coefficients and bulk moduli. hcp-Ir0.55Os0.45 alloy shows bulk moduli B0 = 395 GPa. Thermal expansion coefficients were estimated as α = 1.6·10-5 K-1 at ambient pressure and α = 0.3·10-5 K-1 at 80 GPa. Obtained high-pressure high-temperature data allowed us to construct the first model for pressure-dependent Ir–Os phase diagram.

  15. Rad-hard Location and Attitude Module (R-LAM), Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — R-LAM (Rad-hard Location and Attitude Module), promises a new generation of both integrated navigation modules and stand-alone navigation subsystems including...

  16. Rad-hard embedded computers for nuclear robotics; Calculateurs durcis embarques pour la robotique nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Giraud, A; Joffre, F; Marceau, M; Robiolle, M; Brunet, J P; Mijuin, D

    1994-12-31

    For requirements of nuclear industries, it is necessary to use robots with embedded rad hard electronics and high level safety. The computer developed for french research program SYROCO is presented in this paper. (authors). 8 refs., 5 figs.

  17. Rad-hard Smallsat / CubeSat Avionics Board, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — VORAGO will design a rad-hard Smallsat / CubeSat Avionics single board that has the necessary robustness needed for long duration missions in harsh mission...

  18. RadNet Map Interface for Near-Real-Time Radiation Monitoring Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — RadNet is a national network of monitoring stations that regularly collect air, precipitation, drinking water, and milk samples for analysis of radioactivity. The...

  19. Wide Temperature Rad-Hard ASIC for Process Control of a Fuel Cell System, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Ridgetop Group developed a top-level design of a rad-hard application-specific integrated circuit (ASIC) for spacecraft power management that is functional over a...

  20. Proto-jet configurations in RADs orbiting a Kerr SMBH: symmetries and limiting surfaces

    Science.gov (United States)

    Pugliese, D.; Stuchlík, Z.

    2018-05-01

    Ringed accretion disks (RADs) are agglomerations of perfect-fluid tori orbiting around a single central attractor that could arise during complex matter inflows in active galactic nuclei. We focus our analysis to axi-symmetric accretion tori orbiting in the equatorial plane of a supermassive Kerr black hole; equilibrium configurations, possible instabilities, and evolutionary sequences of RADs were discussed in our previous works. In the present work we discuss special instabilities related to open equipotential surfaces governing the material funnels emerging at various regions of the RADs, being located between two or more individual toroidal configurations of the agglomerate. These open structures could be associated to proto-jets. Boundary limiting surfaces are highlighted, connecting the emergency of the jet-like instabilities with the black hole dimensionless spin. These instabilities are observationally significant for active galactic nuclei, being related to outflows of matter in jets emerging from more than one torus of RADs orbiting around supermassive black holes.

  1. The role of Candida albicans homologous recombination factors Rad54 and Rdh54 in DNA damage sensitivity

    Directory of Open Access Journals (Sweden)

    White Theodore C

    2011-09-01

    Full Text Available Abstract Background The fungal pathogen Candida albicans is frequently seen in immune suppressed patients, and resistance to one of the most widely used antifungals, fluconazole (FLC, can evolve rapidly. In recent years it has become clear that plasticity of the Candida albicans genome contributes to drug resistance through loss of heterozygosity (LOH at resistance genes and gross chromosomal rearrangements that amplify gene copy number of resistance associated genes. This study addresses the role of the homologous recombination factors Rad54 and Rdh54 in cell growth, DNA damage and FLC resistance in Candida albicans. Results The data presented here support a role for homologous recombination in cell growth and DNA damage sensitivity, as Candida albicans rad54Δ/rad54Δ mutants were hypersensitive to MMS and menadione, and had an aberrant cell and nuclear morphology. The Candida albicans rad54Δ/rad54Δ mutant was defective in invasion of Spider agar, presumably due to the altered cellular morphology. In contrast, mutation of the related gene RDH54 did not contribute significantly to DNA damage resistance and cell growth, and deletion of either Candida albicans RAD54 or Candida albicans RDH54 did not alter FLC susceptibility. Conclusions Together, these results support a role for homologous recombination in genome stability under nondamaging conditions. The nuclear morphology defects in the rad54Δ/rad54Δ mutants show that Rad54 performs an essential role during mitotic growth and that in its absence, cells arrest in G2. The viability of the single mutant rad54Δ/rad54Δ and the inability to construct the double mutant rad54Δ/rad54Δ rdh54Δ/rdh54Δ suggests that Rdh54 can partially compensate for Rad54 during mitotic growth.

  2. Measurements of the neutral particle spectra on Mars by MSL/RAD from 2015-11-15 to 2016-01-15

    Science.gov (United States)

    Guo, Jingnan; Zeitlin, Cary; Wimmer-Schweingruber, Robert; Hassler, Donald M.; Köhler, Jan; Ehresmann, Bent; Böttcher, Stephan; Böhm, Eckart; Brinza, David E.

    2017-08-01

    The Radiation Assessment Detector (RAD), onboard the Mars Science Laboratory (MSL) rover Curiosity, has been measuring the energetic charged and neutral particles and the radiation dose rate on the surface of Mars since the landing of the rover in August 2012. In contrast to charged particles, neutral particles (neutrons and γ-rays) are measured indirectly: the energy deposition spectra produced by neutral particles are complex convolutions of the incident particle spectra with the detector response functions. An inversion technique has been developed and applied to jointly unfold the deposited energy spectra measured in two scintillators of different types (CsI for high γ detection efficiency, and plastic for neutrons) to obtain the neutron and γ-ray spectra. This result is important for determining the biological impact of the Martian surface radiation contributed by neutrons, which interact with materials differently from the charged particles. These first in-situ measurements on Mars provide (1) an important reference for assessing the radiation-associated health risks for future manned missions to the red planet and (2) an experimental input for validating the particle transport codes used to model the radiation environments within spacecraft or on the surface of planets. Here we present neutral particle spectra as well as the corresponding dose and dose equivalent rates derived from RAD measurement during a period (November 15, 2015 to January 15, 2016) for which the surface particle spectra have been simulated via different transport models.

  3. Positive Predictive Value of BI-RADS Categorization in an Asian Population

    Directory of Open Access Journals (Sweden)

    Yah-Yuen Tan

    2004-07-01

    Full Text Available The Breast Imaging Reporting And Data System (BI-RADS categorization of mammograms is useful in estimating the risk of malignancy, thereby guiding management decisions. However, in Asian women, in whom breast density is increased, the sensitivity of mammography is correspondingly lower. We sought to determine the positive predictive value of BI-RADS categorization for malignancy in our Asian population and, hence, its value in helping us to choose between the various modalities for breast biopsy. We retrospectively reviewed all patients with occult breast lesions detected on mammography or ultrasound who underwent needle-localization open breast biopsy (NLOB in our institution over a 6-year period. There were 470 biopsies in 427 patients; 16% of lesions were malignant. The positive predictive value of BI-RADS 4 and 5 lesions for cancer was 0.27 and 0.84, respectively. While most BI-RADS 5 mass lesions were invasive cancers, the majority of calcifications in this category were in situ carcinomas. We conclude that BI-RADS remains useful in aiding decision-making for biopsy in our Asian population. Based on positive predictive values, we recommend percutaneous breast biopsy for initial evaluation of lesions categorized as BI-RADS 4 or less. For BI-RADS 5 lesions with microcalcifications, open surgical biopsy as a diagnostic and therapeutic procedure may be more appropriate. In the case of a BI-RADS 5 lesion associated with a mass, initial percutaneous biopsy may be useful for diagnosis, followed by a planned single-stage surgical procedure as necessary.

  4. Performance of the RAD-57 pulse CO-oximeter compared with standard laboratory carboxyhemoglobin measurement.

    Science.gov (United States)

    Touger, Michael; Birnbaum, Adrienne; Wang, Jessica; Chou, Katherine; Pearson, Darion; Bijur, Polly

    2010-10-01

    We assess agreement between carboxyhemoglobin levels measured by the Rad-57 signal extraction pulse CO-oximeter (RAD), a Food and Drug Administration-approved device for noninvasive bedside measurement, and standard laboratory arterial or venous measurement in a sample of emergency department (ED) patients with suspected carbon monoxide poisoning. The study was a cross-sectional cohort design using a convenience sample of adult and pediatric ED patients in a Level I trauma, burn, and hyperbaric oxygen referral center. Measurement of RAD carboxyhemoglobin was performed simultaneously with blood sampling for laboratory determination of carboxyhemoglobin level. The difference between the measures for each patient was calculated as laboratory carboxyhemoglobin minus carboxyhemoglobin from the carbon monoxide oximeter. The limits of agreement from a Bland-Altman analysis are calculated as the mean of the differences between methods ±1.96 SDs above and below the mean. Median laboratory percentage carboxyhemoglobin level was 2.3% (interquartile range 1 to 8.5; range 0% to 38%). The mean difference between laboratory carboxyhemoglobin values and RAD values was 1.4% carboxyhemoglobin (95% confidence interval [CI] 0.2% to 2.6%). The limits of agreement of differences of measurement made with the 2 devices were -11.6% and 14.4% carboxyhemoglobin. This range exceeded the value of ±5% carboxyhemoglobin defined a priori as clinically acceptable. RAD correctly identified 11 of 23 patients with laboratory values greater than 15% carboxyhemoglobin (sensitivity 48%; 95% CI 27% to 69%). There was one case of a laboratory carboxyhemoglobin level less than 15%, in which the RAD device gave a result greater than 15% (specificity of RAD 96/97=99%; 95% CI 94% to 100%). In the range of carboxyhemoglobin values measured in this sample, the level of agreement observed suggests RAD measurement may not be used interchangeably with standard laboratory measurement. Copyright © 2010 American

  5. Issues in assessing multi-institutional performance of BI-RADS-based CAD systems

    Science.gov (United States)

    Markey, Mia K.; Lo, Joseph Y.

    2005-04-01

    The purpose of this study was to investigate factors that impact the generalization of breast cancer computer-aided diagnosis (CAD) systems that utilize the Breast Imaging Reporting and Data System (BI-RADS). Data sets from four institutions were analyzed: Duke University Medical Center, University of Pennsylvania Medical Center, Massachusetts General Hospital, and Wake Forest University. The latter two data sets are subsets of the Digital Database for Screening Mammography. Each data set consisted of descriptions of mammographic lesions according to the BI-RADS lexicon, patient age, and pathology status (benign/malignant). Models were developed to predict pathology status from the BI-RADS descriptors and the patient age. Comparisons between the models built on data from the different institutions were made in terms of empirical (non-parametric) receiver operating characteristic (ROC) curves. Results suggest that BI-RADS-based CAD systems focused on specific classes of lesions may be more generally applicable than models that cover several lesion types. However, better generalization was seen in terms of the area under the ROC curve than in the partial area index (>90% sensitivity). Previous studies have illustrated the challenges in translating a BI-RADS-based CAD system from one institution to another. This study provides new insights into possible approaches to improve the generalization of BI-RADS-based CAD systems.

  6. The rad-hard readout system of the BaBar silicon vertex tracker

    Science.gov (United States)

    Re, V.; DeWitt, J.; Dow, S.; Frey, A.; Johnson, R. P.; Kroeger, W.; Kipnis, I.; Leona, A.; Luo, L.; Mandelli, E.; Manfredi, P. F.; Nyman, M.; Pedrali-Noy, M.; Poplevin, P.; Perazzo, A.; Roe, N.; Spencer, N.

    1998-02-01

    This paper discusses the behaviour of a prototype rad-hard version of the chip developed for the readout of the BaBar silicon vertex tracker. A previous version of the chip, implemented in the 0.8 μm HP rad-soft version has been thoroughly tested in the recent times. It featured outstanding noise characteristics and showed that the specifications assumed as target for the tracker readout were met to a very good extent. The next step was the realization of a chip prototype in the rad-hard process that will be employed in the actual chip production. Such a prototype is structurally and functionally identical to its rad-soft predecessor. However, the process parameters being different, and not fully mastered at the time of design, some deviations in the behaviour were to be expected. The reasons for such deviations have been identified and some of them were removed by acting on the points that were left accessible on the chip. Other required small circuit modifications that will not affect the production schedule. The tests done so far on the rad-hard chip have shown that the noise behaviour is very close to that of the rad-soft version, that is fully adequate for the vertex detector readout.

  7. Overexpressed of RAD51 suppresses recombination defects: a possible mechanism to reverse genomic instability

    Energy Technology Data Exchange (ETDEWEB)

    Schild, David; Wiese, Claudia

    2009-10-15

    RAD51, a key protein in the homologous recombinational DNA repair (HRR) pathway, is the major strand-transferase required for mitotic recombination. An important early step in HRR is the formation of single-stranded DNA (ss-DNA) coated by RPA (a ss-DNA binding protein). Displacement of RPA by RAD51 is highly regulated and facilitated by a number of different proteins known as the 'recombination mediators'. To assist these recombination mediators, a second group of proteins also is required and we are defining these proteins here as 'recombination co-mediators'. Defects in either recombination mediators or comediators, including BRCA1 and BRCA2, lead to impaired HRR that can genetically be complemented for (i.e. suppressed) by overexpression of RAD51. Defects in HRR have long been known to contribute to genomic instability leading to tumor development. Since genomic instability also slows cell growth, precancerous cells presumably require genomic restabilization to gain a growth advantage. RAD51 is overexpressed in many tumors, and therefore, we hypothesize that the complementing ability of elevated levels of RAD51 in tumors with initial HRR defects limits genomic instability during carcinogenic progression. Of particular interest, this model may also help explain the high frequency of TP53 mutations in human cancers, since wild-type p53 represses RAD51.

  8. Rad10 exhibits lesion-dependent genetic requirements for recruitment to DNA double-strand breaks in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Moore, Destaye M; Karlin, Justin; González-Barrera, Sergio

    2009-01-01

    In the yeast Saccharomyces cerevisiae, the Rad1-Rad10 protein complex participates in nucleotide excision repair (NER) and homologous recombination (HR). During HR, the Rad1-Rad10 endonuclease cleaves 3' branches of DNA and aberrant 3' DNA ends that are refractory to other 3' processing enzymes. ...

  9. Determination of gonad, eye and bone marrow doses with EMI-5005 head and whole body scans

    International Nuclear Information System (INIS)

    Nishizawa, Kanae; Iwata, Takeo; Furuya, Yoshiro; Maruyama, Takashi; Hashizume, Tadashi.

    1979-01-01

    Dose determinations of tissues and organs during head and whole body scanning with an EMI computed tomographic equipment have been carried out using a Rando woman phantom. The surface dose on the phantom was measured with a Sakura lith Contact film dosimeter system. The absorbed doses in the eyes, thyroids, ovaries and the bone marrow were measured with a thermoluminescent dosimeter. The resultant surface doses for head scanning were 2.8 rad (28 mGy) per scan at maximum and 0.26 rad (2.6 mGy) per scan at minimum, and the doses for whole body scanning were 2.7 rad (27 mGy) per scan at maximum and 0.1 rad (1.0 mGy) per scan at minimum. For the complete gynecological scanning consisting of 8 slices, the eye, thyroid, ovary and the bone marrow dose was 2.4 mrad (24 μGy), 3.5 mrad (35 μGy), 500 mrad (5 mGy) and 225 mrad (2.25 mGy), respectively. And, for a typical head scanning consisting of 5 slices, the eye, thyroid, ovary and the bone marrow dose was 1400 mrad (14 mGy), 46 mrad (460 μGy), 0.60 mrad (6 μGy) and 73 mrad (730 μGy), respectively. (author)

  10. Sterilization of boll weevil pupae with fractionated doses of gamma irradiation

    International Nuclear Information System (INIS)

    Haynes, J.W.; Mitlin, N.; Davich, T.B.; Dawson, J.R.; McGovern, W.L.; McKibben, G.H.

    1977-01-01

    Fractionated doses of 6,250-8,000 rads of gamma irradiation administered to pupae of the boll weevil, Anthonomus grandis Boh., sexually sterilized both sexes. Mortality of males thus treated with 6,250 and 8,000 rads via fractionation was 14% and 27% respectively, by 5 days posttreatment compared with 46% mortality when an equivalent acute dose was administered to newly emerged adults. Pheromone production of males irradiated at 6,250 rads was one-third that of the control for the first 4 days, but equal that of the control during 5-11 days posttreatment. This procedure lends itself to the large-scale sterilization of weevils needed in an eradication program. This technique is applicable to other insects that are highly susceptible to acute doses

  11. A Rad53 Independent Function of Rad9 Becomes Crucial for Genome Maintenance in the Absence of the RecQ Helicase Sgs1

    DEFF Research Database (Denmark)

    Nielsen, Ida; Bentsen, Iben Bach; Andersen, Anni Hangaard

    2013-01-01

    becomes crucial for genome maintenance in the absence of Sgs1. Despite this, our dissection of the MMS checkpoint response reveals parallel, but unequal pathways for Rad53 activation and highlights significant differences between MMS- and hydroxyurea (HU)-induced checkpoint responses with relation...

  12. RadWorks Project. ISS REM - to - BIRD - to - HERA: The Evolution of a Technology

    Science.gov (United States)

    McLeod, Catherine D.

    2015-01-01

    The advancement of particle detectors based on technologies developed for use in high-energy physics applications has enabled the development of a completely new generation of compact low-power active dosimeters and area monitors for use in space radiation environments. One such device, the TimePix, is being developed at CERN, and is providing the technology basis for the most recent line of radiation detection devices being developed by the NASA AES RadWorks project. The most fundamental of these devices, an ISS-Radiation Environment Monitor (REM), is installed as a USB device on ISS where it is monitoring the radiation environment on a perpetual basis. The second generation of this TimePix technology, the BIRD (Battery-operated Independent Radiation Detector), was flown on the NASA EFT-1 flight in December 2014. Data collected by BIRD was the first data made available from the Trapped Belt region of the Earth's atmosphere in over 40 years. The 3rdgeneration of this technology, the HERA (Hybrid Electronic Radiation Assessor), is planned to be integrated into the Orion EM-1, and EM-2 vehicles where it will monitor the radiation environment. For the EM-2 flight, HERA will provide Caution and Warning notification for SPEs as well as real time dose measurements for crew members. The development of this line of radiation detectors provide much greater information and characterization of charged particles in the space radiation environment than has been collected in the past, and in the process provide greater information to inform crew members of radiation related risks, while being very power and mass efficient.

  13. Relationship of time--dose factors to tumor control and complications in the treatment of Cushing's disease by irradiation

    International Nuclear Information System (INIS)

    Aristizabal, S.; Caldwell, W.L.; Avila, J.; Mayer, E.G.

    1977-01-01

    The records of the Radiotherapy Division of the Radiology Department of Vanderbilt University Hospital were reviewed for the period 1952 to 1970. During those 19 years 45 patients with a well-documented diagnosis of Cushing's disease were treated initially by external irradiation of the pituitary. All of the patients were treated with megavoltage equipment using photons. When the results of irradiation are compared against total doses of radiation, it is evident that the control rate is unsatisfactory at doses less than 4000 rad and the maximum benefits of irradiation are evident in the 4500 to 5000 rad dose range. It is also clear that the complication rate increases as the dose exceeds 4800 rad. If the various treatment regimens of irradiation are converted to ''equivalent'' doses by the Nominal Standard Dose (NSD) or Time-Dose-Fractionation (TDF) methods, the relationship between ''dose'' and efficacy of therapy and complications is demonstrated. In order to reduce the possibility of treatment-related morbidity, the use of three or more small (4 x 4 cm) treatment portals or rotational techniques is recommended to a pituitary dose of 4600 to 5000 rad treating 5 days a week for 5 to 6 weeks

  14. Magnetism and transport studies in off-stoichiometric metallic perovskite compounds GdPd{sub 3}B{sub x} (x=0.25, 0.50 and 0.75)

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Abhishek, E-mail: abhishek.phy@gmail.co [S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700098 (India); Experimental Condensed Matter Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India); Mazumdar, Chandan, E-mail: chandan.mazumdar@saha.ac.i [Experimental Condensed Matter Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India); Ranganathan, R. [Experimental Condensed Matter Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India)

    2010-12-15

    We report the magnetic and transport properties of the off-stoichiometric metallic perovskite like compounds GdPd{sub 3}B{sub x} (x=0.25, 0.50 and 0.75). Our results show that doping with boron in the lattice of parent binary-compound GdPd{sub 3} leads to lattice expansion. Which in turn manifests in contrasting magnetic and transport behaviors of the doped compounds in comparison with the undoped GdPd{sub 3}. An attempt has been made to compare and correlate the results of magnetic and transport measurements of GdPd{sub 3}B{sub x} with that of stoichiometric compositions GdPd{sub 3}B{sub x}C{sub 1-x}. The comparative study of GdPd{sub 3}B{sub x} and GdPd{sub 3}B{sub x}C{sub 1-x} confirms that there is a strong correlations between the structural, magnetic and transport properties of these compounds.

  15. The role of antiphase boundaries in the kinetic process of the L12→ D022 structural change of an Ni3Al0.45V0.50 alloy

    International Nuclear Information System (INIS)

    Tanimura, Makoto; Koyama, Yasumasa

    2006-01-01

    The influence of antiphase boundaries (APBs) on the kinetic process of the L1 2 → D0 22 structural change in an Ni 3 Al 0.45 V 0.50 alloy has been investigated by transmission electron microscopy. The structural change includes two kinetic factors, i.e., the periodic introduction of antiphase-shifted planes (APSPs) in the L1 2 structure and V diffusion in the L1 2 matrix. Our results revealed that APB migration was accompanied by V diffusion as if to sweep the V atoms out of the antiphase domains (APDs). It was also found that the APBs served as the nucleation sites of the D0 22 regions, because the combination of the migrated APBs produced the APSPs in the L1 2 structure. On this basis, it is proposed that the APBs bring together the two kinetic factors in the process of the L1 2 → D0 22 structural change, the physical origin of which is the variation in the charge density distribution of the APDs due to APB migration

  16. Electromechanical Anisotropy at the Ferroelectric to Relaxor Transition of (Bi0.5Na0.50.94Ba0.06TiO3 Ceramics from the Thermal Evolution of Resonance Curves

    Directory of Open Access Journals (Sweden)

    Nicolás Pérez

    2018-01-01

    Full Text Available (Bi0.5Na0.50.94Ba0.06TiO3 dense ceramics were obtained from autocombustion sol-gel synthesized nanopowders and sintered at 1050 °C for 1–2 h for the study of the electromechanical anisotropy. Measurement of the complex impedance spectrum was carried out on thin ceramic disks, thickness-poled, as a function of the temperature from 16 °C up to the vanishing of the electromechanical resonances at the ferroelectric to relaxor transition near 100 °C. The spectrum comprises the fundamental radial extensional mode and three overtones of this, together with the fundamental thickness extensional mode, coupled with other complex modes. Thermal evolution of the spectrum shows anisotropic behavior. Piezoelectric, elastic, and dielectric material coefficients, including all losses, were determined from iterative analysis of the complex impedance curves at the planar, thickness, and shear virtually monomodal resonances of disks and shear plates, thickness-poled. d33 was measured quasi-statically at 100 Hz. This set of data was used as the initial condition for the optimization of the numerical calculation by finite elements of the full spectrum of the disk, from 100 kHz to 1.9 MHz, to determine the thermal evolution of the material coefficients. An appropriate measurement strategy to study electromechanical anisotropy of piezoelectric ceramics has been developed.

  17. The Effects of a High Magnetic Field on the Annealing of [(Fe0.5Co0.50.75B0.2Si0.05]96Nb4 Bulk Metallic Glass

    Directory of Open Access Journals (Sweden)

    Peng Jia

    2016-11-01

    Full Text Available In contrast with amorphous alloys, nanocrystalline soft magnetic materials show improved thermal stability and higher soft magnetic properties. The nanocrystalline soft magnetic composites are usually fabricated by partially crystallizing from parent amorphous alloys. This paper reports our experimental observation on the sequence of crystallization in metallic glass under a high magnetic field (HMF. An application of a HMF to bulk metallic glass (BMG of [(Fe0.5Co0.50.75B0.2Si0.05]96Nb4 prioritizes the precipitation of α-(Fe,Co phase separated from the subsequent precipitation of borides, (Fe,Co23B6, upon isothermal annealing at a glass transition temperature. Furthermore, it was observed that, through the annealing treatment under a HMF, a soft magnetic nanocomposite, in which only α-(Fe,Co phase uniformly distributes in amorphous matrix, was achieved for boron-bearing BMG. The promotion of the α-Fe or (Fe,Co phase and the prevention of the boride phases during the isothermal annealing process help to produce high-quality soft magnetic nanocomposite materials. The mechanism by which a HMF influences the crystallization sequence was interpreted via certain changes in Gibbs free energies for two ferromagnetic phases. This finding evidences that the annealing treatment under a HMF is suitable for enhancing the soft magnetic properties of high B content (Fe,Co-based bulk amorphous and nanocrystalline materials.

  18. Radiation dose from solar flares at ground level

    International Nuclear Information System (INIS)

    O'Brien, K.

    1979-01-01

    Wdowczyk and Wolfendale (Nature, 268, 510, 1977) concluded that a very large solar flare producing exposure of 10 4 rad at ground level (lethal to almost any organism) has a possible frequency of once per 10 5 -10 8 yr. In the work reported similar results were obtained using a more elaborate model. Flares occuring from February 1956 to August 1972 were analyzed. The flare size distribution above the earth's atmosphere, and neutron flux, dose and dose equivalent at ground level at the latitude of Deep River, Canada, were calculated. The probable frequency of flares delivering various doses are given. Doses larger than 100 rad which have significant somatic effects on man and other animals may be delivered once in 10 6 years. The probability of 10 4 rad was found to be 10 -8 /yr. These calculations apply only to high geomagnetic latitudes. Field reversals during which the geomagnetic field is much weaker than current values total about 10% of the past 4 million years. This suggests that a very large flare delivering a large dose worldwide at ground level cannot be ruled out. (author)

  19. Late biological effects of ionizing radiation as influenced by dose, dose rate, age at exposure, and genetic sensitivity to neoplastic transformation

    International Nuclear Information System (INIS)

    Spalding, J.F.; Prine, J.R.; Tietjen, G.L.

    1978-01-01

    A most comprehensive investigation is in progress at the Los Alamos Scientific Laboratory to study the late biological effects of whole-body exposure to gamma irradiation as they may be influenced by total dose, dose rate, age at exposure, and genetic background. Strain C57B1/6J mice of four age groups (newborn, 2, 6, and 15 months) were given five doses (20, 60, 180, 540, and 1620 rad) of gamma rays, with each dose being delivered at six dose rates (0.7, 2.1, 6.3, 18.9, 56.7 rad/day and 25 rad/min). Forty to sixty mice were used in each of the approximately 110 dose/dose-rate and age combinations. The study was done in two replications with an equal number of mice per replication. Strain RF/J mice were used in a companion study to investigate the influence of genetic background on the type and magnitude of effect. Results of the first and second replications of the 15-month-old age group and data on the influence of genetic background on biological response have been completed, and the results show no significant life shortening within the dose and dose-rate range used

  20. Late biological effects of ionizing radiation as influenced by dose, dose rate, age at exposure and genetic sensitivity to neoplastic transformation

    International Nuclear Information System (INIS)

    Spalding, J.F.; Prine, J.R.; Tietjen, G.L.

    1978-01-01

    A most comprehensive investigation is in progress at the Los Alamos Scientific Laboratory to study the late biological effects of whole-body exposure to gamma irradiation as they may be influenced by total dose, dose rate, age at exposure and genetic background. Strain C57B1/6J mice of four age groups (newborn, 2, 6 and l5 months) were given five doses (20, 60, 180, 540, and 1620 rads) of gamma rays, with each dose being delivered at six dose rates (0.7, 2.1, 6.3, 18.9, 56.7 rads/day and 25 rads/min). Forty to sixty mice were used in each of the approximately 119 dose/dose-rate and age combinations. The study was done in two replications with an equal number of mice per replicaton. Strain RF/J mice were used in a companion study to investigate the influence of genetic background on the type and magnitude of effect. Results of the first and second replications of the l5-month-old age group and data on the influence of genetic background on biological response have been completed, and the results show no significant life shortening within the dose and dose-rate range used. It was also concluded that radiaton-induced neoplastic transformaton was significantly greater in mice with a known genetic sensitivity to neoplastic disease than in mammals which do not normally have a significant incidence of tumours. (author)

  1. Radiation absorbed dose to the lens in dacryoscintigraphy with /sup 99m/TcO4-1

    International Nuclear Information System (INIS)

    Robertson, J.S.; Brown, M.L.; Colvard, D.M.

    1979-01-01

    Calculations of the radiation dose to the lens for /sup 99m/TcO 4 - in dacryoscintigraphy are developed in some detail. The results indicate that the absorbed dose to the germinal epithelium of the lens is 2.2 x 10 -5 to 1.4 x 10 -4 rad/μCi (5.9 x 10 -12 to 3.8 x 10 -11 Gy/Bq) /sup 99m/TcO 4 - under physiological conditions. With blockage of the lacrimal drainage apparatus, the dose to the lens could increase to 4 x 10 -3 rad/μCi

  2. Requirement of Sequences outside the Conserved Kinase Domain of Fission Yeast Rad3p for Checkpoint Control

    Science.gov (United States)

    Chapman, Carolyn Riley; Evans, Sarah Tyler; Carr, Antony M.; Enoch, Tamar

    1999-01-01

    The fission yeast Rad3p checkpoint protein is a member of the phosphatidylinositol 3-kinase-related family of protein kinases, which includes human ATMp. Mutation of the ATM gene is responsible for the disease ataxia-telangiectasia. The kinase domain of Rad3p has previously been shown to be essential for function. Here, we show that although this domain is necessary, it is not sufficient, because the isolated kinase domain does not have kinase activity in vitro and cannot complement a rad3 deletion strain. Using dominant negative alleles of rad3, we have identified two sites N-terminal to the conserved kinase domain that are essential for Rad3p function. One of these sites is the putative leucine zipper, which is conserved in other phosphatidylinositol 3-kinase-related family members. The other is a novel motif, which may also mediate Rad3p protein–protein interactions. PMID:10512862

  3. Studies on the chronic effect of lower dose level irradiation

    International Nuclear Information System (INIS)

    Yun, T.G.; Yun, E.S.; Chung, I.Y.; Yun, M.S.; Chae, H.S.; Lee, J.Y.

    1982-01-01

    This experiment was carried out to evaluate the chronic hazard of Co-60 low dose radiation on ICR mice. There is now considerable evidence from human studies that age, both at exposure to radiation and at observation for risk, can be major determinant of radiation induced cancer risk. For this reason, ICR mice at different ages such as below were exposed to 60m rads/week, 500m rads/week and 60 rads/biweek whole body Co-60 radiation at a dose rate of 3.6 rads/min. ICR mice were irradiated during pregnant period, from 1st week to 3rd week, from 3rd week to 52nd week, from 6th week to 52nd week, and from 22nd week to 52nd week after the birth. All experimental mice were autopsied immediately after being sacrificed at 52nd week. All major organs were examined grossly and weighed. After fixation histo-pathological preparations were made for microscopical study. Blood cells W.B.C., R.B.C., Hb-from eye's vein were counted by hemocytometer and hemometer. (Author)

  4. Electron dosimetry in irradiation processing with rad-hard diodes

    International Nuclear Information System (INIS)

    Santos, Thais Cavalheri dos

    2012-01-01

    This work had the aim of the development of dosimetric systems based on Si special diodes, resistant to radiation damage to online monitoring of irradiation processing using 1.5 MeV electrons energy and for relative dosimetry and clinical electron beam scanning within an energy range of 6 MeV up to 21 MeV. The diodes used were produced by Float Zone standard (FZ), Magnetic Czochralski (MCz) and epitaxy growth (EPI) methods. In order to use the diodes as detectors, they were fixed on alumina base to allow the connection of the polarization electrodes and the signals extraction. After the diode assembly on the base, each one was housed in a black acrylic probe with aluminized Mylar® window and LEMO® connector. With the devices operating in photovoltaic mode, the integration of the current signals as a function of irradiation time allowed obtain the charge produced in the sensitive volume of each diode irradiated. The electron accelerator used for high doses irradiation was the DC 1500/25/4 JOB 188 of the 1.5 MeV installed at the Radiation Technology Center of the IPEN/CNEN-SP. The current profile as function of exposure time, the response repeatability, the sensitivity as function of absorbed dose and the dose response curve were studied for each device. In comparison to FZ diode, we observed a greater decrease in the sensitivity for MCz diode, and good repeatability in both cases. Also, the increasing of the charge with the absorbed dose was well fitted by a second order polynomial function. In the EPI diode characterization, this one exhibited repeatability better than CTA dosimeters applied routinely in radiation processing. The above results indicate the potential use of these radiation hardness Si diodes in online dosimetry to high doses applications. For low doses irradiation were used the linear accelerators KD2 and Primus, both manufactured by Siemens and located at Sirio-Libanes Hospital. The diodes responses were evaluated for electron beams within the

  5. Chromosome aberrations induced by low doses of X-rays in human lymphocytes in vitro

    International Nuclear Information System (INIS)

    Ziemba-Zoltowska, B.; Bocian, E.; Rosiek, O.; Sablinski, J.

    1980-01-01

    Curves derived from the dose-response data for the yield of aberrations in human lymphocytes can be represented by a quadratic equation at all but low dose ranges. A calibration curve has therefore been determined at a low dose range of X-radiation (11.5 to 57.5 rad). The frequencies of dicentrics plus centric rings, and of acentrics were better fitted by linear dose-response models than quadratic. The linearity of the relationship indicated that asymmetrical chromosome exchanges at low doses of radiation are produced predominantly by a single track mechanism. A dose-response curve for dicentrics plus centric rings (5 to 60 rad) has also been derived by pooling published data with the results of this study. This calibration curve is relevant to cytogenetic dosimetry in radiological protection. (UK)

  6. Identification of a breast cancer family double heterozygote for RAD51C and BRCA2 gene mutations

    DEFF Research Database (Denmark)

    Ahlborn, Lise B; Steffensen, Ane Y; Jønson, Lars

    2015-01-01

    for mutations in the RAD51C and BRCA2 genes. The RAD51C missense mutation p.Arg258His has previously been identified in a homozygous state in a patient with Fanconi anemia. This mutation is known to affect the DNA repair function of the RAD51C protein. The BRCA2 p.Leu3216Leu synonymous mutation has not been...

  7. Substantial differences in bias between single-digest and double-digest RAD-seq libraries: A case study.

    Science.gov (United States)

    Flanagan, Sarah P; Jones, Adam G

    2018-03-01

    The trade-offs of using single-digest vs. double-digest restriction site-associated DNA sequencing (RAD-seq) protocols have been widely discussed. However, no direct empirical comparisons of the two methods have been conducted. Here, we sampled a single population of Gulf pipefish (Syngnathus scovelli) and genotyped 444 individuals using RAD-seq. Sixty individuals were subjected to single-digest RAD-seq (sdRAD-seq), and the remaining 384 individuals were genotyped using a double-digest RAD-seq (ddRAD-seq) protocol. We analysed the resulting Illumina sequencing data and compared the two genotyping methods when reads were analysed either together or separately. Coverage statistics, observed heterozygosity, and allele frequencies differed significantly between the two protocols, as did the results of selection components analysis. We also performed an in silico digestion of the Gulf pipefish genome and modelled five major sources of bias: PCR duplicates, polymorphic restriction sites, shearing bias, asymmetric sampling (i.e., genotyping fewer individuals with sdRAD-seq than with ddRAD-seq) and higher major allele frequencies. This combination of approaches allowed us to determine that polymorphic restriction sites, an asymmetric sampling scheme, mean allele frequencies and to some extent PCR duplicates all contribute to different estimates of allele frequencies between samples genotyped using sdRAD-seq versus ddRAD-seq. Our finding that sdRAD-seq and ddRAD-seq can result in different allele frequencies has implications for comparisons across studies and techniques that endeavour to identify genomewide signatures of evolutionary processes in natural populations. © 2017 John Wiley & Sons Ltd.

  8. Tomosynthesis in the Diagnostic Setting: Changing Rates of BI-RADS Final Assessment over Time.

    Science.gov (United States)

    Raghu, Madhavi; Durand, Melissa A; Andrejeva, Liva; Goehler, Alexander; Michalski, Mark H; Geisel, Jaime L; Hooley, Regina J; Horvath, Laura J; Butler, Reni; Forman, Howard P; Philpotts, Liane E

    2016-10-01

    Purpose To evaluate the effect of tomosynthesis in diagnostic mammography on the Breast Imaging Reporting and Data System (BI-RADS) final assessment categories over time. Materials and Methods This retrospective study was approved by the institutional review board. The authors reviewed all diagnostic mammograms obtained during a 12-month interval before (two-dimensional [2D] mammography [June 2, 2010, to June 1, 2011]) and for 3 consecutive years after (tomosynthesis year 1 [2012], tomosynthesis year 2 [2013], and tomosynthesis year 3 [2014]) the implementation of tomosynthesis. The requirement to obtain informed consent was waived. The rates of BI-RADS final assessment categories 1-5 were compared between the 2D and tomosynthesis groups. The positive predictive values after biopsy (PPV3) for BI-RADS category 4 and 5 cases were compared. The mammographic features (masses, architectural distortions, calcifications, focal asymmetries) of lesions categorized as probably benign (BI-RADS category 3) and those for which biopsy was recommended (BI-RADS category 4 or 5) were reviewed. The χ(2) test was used to compare the rates of BI-RADS final assessment categories 1-5 between the two groups, and multivariate logistic regression analysis was performed to compare all diagnostic studies categorized as BI-RADS 3-5. Results There was an increase in the percentage of cases reported as negative or benign (BI-RADS category 1 or 2) with tomosynthesis (58.7% with 2D mammography vs 75.8% with tomosynthesis at year 3, P tomosynthesis at year 3, P tomosynthesis (8.0% with 2D mammography vs 7.8% with tomosynthesis at year 3, P = .2), there was a significant increase in the PPV3 (29.6% vs 50%, respectively; P tomosynthesis use. Conclusion Tomosynthesis in the diagnostic setting resulted in progressive shifts in the BI-RADS final assessment categories over time, with a significant increase in the proportion of studies classified as normal, a continued decrease in the rate of studies

  9. Doses from Hiroshima mass radiologic gastric surveys

    Energy Technology Data Exchange (ETDEWEB)

    Antoku, S; Sawada, S; Russell, W J [Radiation Effects Research Foundation, Hiroshima (Japan)

    1980-05-01

    Doses to examinees from mass radiologic surveys of the stomach in Hiroshima Perfecture were estimated by surveying for the frequency of the examinations, and for the technical factors used in them, and by phantom dosimetry. The average surface, active bone marrow and male and female gonad doses per examination were 5.73 rad, 231 mrad, and 20.6 and 140 mrad, respectively. These data will be used in estimating doses from medical X-rays among atomic bomb survivors. By applying them to the Hiroshima population, the genetically significant, per caput mean marrow, and leukemia significant doses were 0.14,8.6 and 7.4 mrad, respectively. There was a benefit-to risk ratio of about 50 for mass gastric surveys performed in 1976. However, the calculated risk was greater than the benefit for examinees under 29 years of age because of the lower incidence of gastric cancer in those under 29 years.

  10. Metabolic suppressors of trimethoprim and ultraviolet light sensitivities of Saccharomyces cerevisiae rad6 mutants

    International Nuclear Information System (INIS)

    Lawrence, C.W.; Christensen, R.B.

    1979-01-01

    Dominant mutations at two newly identified loci, designated SRS1 and SRS2, that metabolically suppress the trimethoprim sensitivity of rad6 and rad18 strains, have been isolated from trimethorprim-resistant mutants arising spontaneously in rad6-1 rad18-2 strains of the yeast Saccharomyces cerevisiae. The SRS2 mutations also efficiently suppress the ultraviolet light sensitivity of the parent strains. They do not, however, suppress their sensitivity to ionizing radiation or their deficiency with respect to induced mutagenesis and sporulation. Such observations support the hypothesis that RAD6-dependent activities can be separated into two functionally distinct groups: a group of error-free repair activities that are responsible for a large amount of the radiation resistance of wild-type strains and also for their resistance to trimethoprim, and a group of error-prone activities that are responsible for induced mutagenesis and are also important in sporulation, but which account at best for only a very small amount of wild-type recovery

  11. PI-RADS v2 and ADC values: is there room for improvement?

    Science.gov (United States)

    Jordan, Eric J; Fiske, Charles; Zagoria, Ronald; Westphalen, Antonio C

    2018-03-17

    To determine the diagnostic accuracy of ADC values in combination with PI-RADS v2 for the diagnosis of clinically significant prostate cancer (CS-PCa) compared to PI-RADS v2 alone. This retrospective study included 155 men whom underwent 3-Tesla prostate MRI and subsequent MR/US fusion biopsies at a single non-academic center from 11/2014 to 3/2016. All scans were performed with a surface coil and included T2, diffusion-weighted, and dynamic contrast-enhanced sequences. Suspicious findings were classified using Prostate Imaging Reporting and Data System (PI-RADS) v2 and targeted using MR/US fusion biopsies. Mixed-effect logistic regression analyses were used to determine the ability of PIRADS v2 alone and combined with ADC values to predict CS-PCa. As ADC categories are more practical in clinical situations than numeric values, an additional model with ADC categories of ≤ 800 and > 800 was performed. A total of 243 suspicious lesions were included, 69 of which were CS-PCa, 34 were Gleason score 3+3 PCa, and 140 were negative. The overall PIRADS v2 score, ADC values, and ADC categories are independent statistically significant predictors of CS-PCa (p values or categories is better discrimination of PI-RADS v2 4 lesions. ADC values and categories help to diagnose CS-PCa when lesions are assigned a PI-RADS v2 score of 4.

  12. The Medicago truncatula GRAS protein RAD1 supports arbuscular mycorrhiza symbiosis and Phytophthora palmivora susceptibility.

    Science.gov (United States)

    Rey, Thomas; Bonhomme, Maxime; Chatterjee, Abhishek; Gavrin, Aleksandr; Toulotte, Justine; Yang, Weibing; André, Olivier; Jacquet, Christophe; Schornack, Sebastian

    2017-12-16

    The roots of most land plants are colonized by symbiotic arbuscular mycorrhiza (AM) fungi. To facilitate this symbiosis, plant genomes encode a set of genes required for microbial perception and accommodation. However, the extent to which infection by filamentous root pathogens also relies on some of these genes remains an open question. Here, we used genome-wide association mapping to identify genes contributing to colonization of Medicago truncatula roots by the pathogenic oomycete Phytophthora palmivora. Single-nucleotide polymorphism (SNP) markers most significantly associated with plant colonization response were identified upstream of RAD1, which encodes a GRAS transcription regulator first negatively implicated in root nodule symbiosis and recently identified as a positive regulator of AM symbiosis. RAD1 transcript levels are up-regulated both in response to AM fungus and, to a lower extent, in infected tissues by P. palmivora where its expression is restricted to root cortex cells proximal to pathogen hyphae. Reverse genetics showed that reduction of RAD1 transcript levels as well as a rad1 mutant are impaired in their full colonization by AM fungi as well as by P. palmivora. Thus, the importance of RAD1 extends beyond symbiotic interactions, suggesting a general involvement in M. truncatula microbe-induced root development and interactions with unrelated beneficial and detrimental filamentous microbes. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  13. Significance and Application of Digital Breast Tomosynthesis for the BI-RADS Classification of Breast Cancer.

    Science.gov (United States)

    Cai, Si-Qing; Yan, Jian-Xiang; Chen, Qing-Shi; Huang, Mei-Ling; Cai, Dong-Lu

    2015-01-01

    Full-field digital mammography (FFDM) with dense breasts has a high rate of missed diagnosis, and digital breast tomosynthesis (DBT) could reduce organization overlapping and provide more reliable images for BI-RADS classification. This study aims to explore application of COMBO (FFDM+DBT) for effect and significance of BI-RADS classification of breast cancer. In this study, we selected 832 patients who had been treated from May 2013 to November 2013. Classify FFDM and COMBO examination according to BI-RADS separately and compare the differences for glands in the image of the same patient in judgment, mass characteristics display and indirect signs. Employ Paired Wilcoxon rank sum test was used in 79 breast cancer patients to find differences between two examine methods. The results indicated that COMBO pattern is able to observe more details in distribution of glands when estimating content. Paired Wilcoxon rank sum test showed that overall classification level of COMBO is higher significantly compared to FFDM to BI-RADS diagnosis and classification of breast (PBI-RADS classification in breast cancer in clinical.

  14. Mammalian RAD52 Functions in Break-Induced Replication Repair of Collapsed DNA Replication Forks.

    Science.gov (United States)

    Sotiriou, Sotirios K; Kamileri, Irene; Lugli, Natalia; Evangelou, Konstantinos; Da-Ré, Caterina; Huber, Florian; Padayachy, Laura; Tardy, Sebastien; Nicati, Noemie L; Barriot, Samia; Ochs, Fena; Lukas, Claudia; Lukas, Jiri; Gorgoulis, Vassilis G; Scapozza, Leonardo; Halazonetis, Thanos D

    2016-12-15

    Human cancers are characterized by the presence of oncogene-induced DNA replication stress (DRS), making them dependent on repair pathways such as break-induced replication (BIR) for damaged DNA replication forks. To better understand BIR, we performed a targeted siRNA screen for genes whose depletion inhibited G1 to S phase progression when oncogenic cyclin E was overexpressed. RAD52, a gene dispensable for normal development in mice, was among the top hits. In cells in which fork collapse was induced by oncogenes or chemicals, the Rad52 protein localized to DRS foci. Depletion of Rad52 by siRNA or knockout of the gene by CRISPR/Cas9 compromised restart of collapsed forks and led to DNA damage in cells experiencing DRS. Furthermore, in cancer-prone, heterozygous APC mutant mice, homozygous deletion of the Rad52 gene suppressed tumor growth and prolonged lifespan. We therefore propose that mammalian RAD52 facilitates repair of collapsed DNA replication forks in cancer cells. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

  15. Checkpoint Kinase Rad53 Couples Leading- and Lagging-Strand DNA Synthesis under Replication Stress.

    Science.gov (United States)

    Gan, Haiyun; Yu, Chuanhe; Devbhandari, Sujan; Sharma, Sushma; Han, Junhong; Chabes, Andrei; Remus, Dirk; Zhang, Zhiguo

    2017-10-19

    The checkpoint kinase Rad53 is activated during replication stress to prevent fork collapse, an essential but poorly understood process. Here we show that Rad53 couples leading- and lagging-strand synthesis under replication stress. In rad53-1 cells stressed by dNTP depletion, the replicative DNA helicase, MCM, and the leading-strand DNA polymerase, Pol ε, move beyond the site of DNA synthesis, likely unwinding template DNA. Remarkably, DNA synthesis progresses further along the lagging strand than the leading strand, resulting in the exposure of long stretches of single-stranded leading-strand template. The asymmetric DNA synthesis in rad53-1 cells is suppressed by elevated levels of dNTPs in vivo, and the activity of Pol ε is compromised more than lagging-strand polymerase Pol δ at low dNTP concentrations in vitro. Therefore, we propose that Rad53 prevents the generation of excessive ssDNA under replication stress by coordinating DNA unwinding with synthesis of both strands. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. RAD51 and RTEL1 compensate telomere loss in the absence of telomerase.

    Science.gov (United States)

    Olivier, Margaux; Charbonnel, Cyril; Amiard, Simon; White, Charles I; Gallego, Maria E

    2018-03-16

    Replicative erosion of telomeres is naturally compensated by telomerase and studies in yeast and vertebrates show that homologous recombination can compensate for the absence of telomerase. We show that RAD51 protein, which catalyzes the key strand-invasion step of homologous recombination, is localized at Arabidopsis telomeres in absence of telomerase. Blocking the strand-transfer activity of the RAD51 in telomerase mutant plants results in a strikingly earlier onset of developmental defects, accompanied by increased numbers of end-to-end chromosome fusions. Imposing replication stress through knockout of RNaseH2 increases numbers of chromosome fusions and reduces the survival of these plants deficient for telomerase and homologous recombination. This finding suggests that RAD51-dependent homologous recombination acts as an essential backup to the telomerase for compensation of replicative telomere loss to ensure genome stability. Furthermore, we show that this positive role of RAD51 in telomere stability is dependent on the RTEL1 helicase. We propose that a RAD51 dependent break-induced replication process is activated in cells lacking telomerase activity, with RTEL1 responsible for D-loop dissolution after telomere replication.

  17. Resolving RAD51C function in late stages of homologous recombination

    Directory of Open Access Journals (Sweden)

    Kuznetsov Sergey G

    2007-06-01

    Full Text Available Abstract DNA double strand breaks are efficiently repaired by homologous recombination. One of the last steps of this process is resolution of Holliday junctions that are formed at the sites of genetic exchange between homologous DNA. Although various resolvases with Holliday junctions processing activity have been identified in bacteriophages, bacteria and archaebacteria, eukaryotic resolvases have been elusive. Recent biochemical evidence has revealed that RAD51C and XRCC3, members of the RAD51-like protein family, are involved in Holliday junction resolution in mammalian cells. However, purified recombinant RAD51C and XRCC3 proteins have not shown any Holliday junction resolution activity. In addition, these proteins did not reveal the presence of a nuclease domain, which raises doubts about their ability to function as a resolvase. Furthermore, oocytes from infertile Rad51C mutant mice exhibit precocious separation of sister chromatids at metaphase II, a phenotype that reflects a defect in sister chromatid cohesion, not a lack of Holliday junction resolution. Here we discuss a model to explain how a Holliday junction resolution defect can lead to sister chromatid separation in mouse oocytes. We also describe other recent in vitro and in vivo evidence supporting a late role for RAD51C in homologous recombination in mammalian cells, which is likely to be resolution of the Holliday junction.

  18. Improving societal acceptance of rad waste management policy decisions: an approach based on complex intelligence

    International Nuclear Information System (INIS)

    Rao, Suman

    2008-01-01

    In today's context elaborate public participation exercises are conducted around the world to elicit and incorporate societal risk perceptions into nuclear policy Decision-Making. However, on many occasions, such as in the case of rad waste management, the society remains unconvinced about these decisions. This naturally leads to the questions: are techniques for incorporating societal risk perceptions into the rad waste policy decision making processes sufficiently mature? How could societal risk perceptions and legal normative principles be better integrated in order to render the decisions more equitable and convincing to society? Based on guidance from socio-psychological research this paper postulates that a critical factor for gaining/improving societal acceptance is the quality and adequacy of criteria for option evaluation that are used in the policy decision making. After surveying three rad waste public participation cases, the paper identifies key lacunae in criteria abstraction processes as currently practiced. A new policy decision support model CIRDA: Complex Intelligent Risk Discourse Abstraction model that is based on the heuristic of Risk-Risk Analysis is proposed to overcome these lacunae. CIRDA's functionality of rad waste policy decision making is modelled as a policy decision-making Abstract Intelligent Agent and the agent program/abstraction mappings are presented. CIRDA is then applied to a live (U.K.) rad waste management case and the advantages of this method as compared to the Value Tree Method as practiced in the GB case are demonstrated. (author)

  19. Yeast DNA-repair gene RAD14 encodes a zinc metalloprotein with affinity for ultraviolet-damaged DNA

    International Nuclear Information System (INIS)

    Guzder, S.N.; Sung, P.; Prakash, S.; Prakash, L.

    1993-01-01

    Xeroderma pigmentosum (XP) patients suffer from a high incidence of skin cancers due to a defect in excision repair of UV light-damaged DNA. Of the seven XP complementation groups, A--G, group A represents a severe and frequent form of the disease. The Saccharomyces cerevisiae RAD14 gene is a homolog of the XP-A correcting (XPAC) gene. Like XP-A cells, rad14-null mutants are defective in the incision step of excision repair of UV-damaged DNA. The authors have purified RAD14 protein to homogeneity from extract of a yeast strain genetically tailored to overexpress RAD14. As determined by atomic emission spectroscopy, RAD14 contains one zinc atom. They also show in vitro that RAD14 binds zinc but does not bind other divalent metal ions. In DNA mobility-shift assays, RAD14 binds specifically to UV-damaged DNA. Removal of cyclobutane pyrimidine dimers from damaged DNA by enzymatic photoreactivation has no effect on binding, strongly suggesting that RAD14 recognizes pyrimidine(6-4)pyrimidone photoproduct sites. These findings indicate that RAD14 functions in damage recognition during excision repair. 37 refs., 4 figs

  20. Structure, microstructure and microhardness of rapidly solidified Smy(FexNi1-x)4Sb12 (x = 0.45, 0.50, 0.70, 1) thermoelectric compounds

    Science.gov (United States)

    Artini, C.; Castellero, A.; Baricco, M.; Buscaglia, M. T.; Carlini, R.

    2018-05-01

    Skutterudites are interesting compounds for thermoelectric applications. The main drawback in the synthesis of skutterudites by solidification of the melt is the occurrence of two peritectic reactions requiring long annealing times to form a single phase. Aim of this work is to investigate an alternative route for synthesis, based on rapid solidification by planar flow casting. The effect of cooling rate on phases formation and composition, as well as on structure, microstructure and mechanical properties of the filled Smy(FexNi1-x)4Sb12 (x = 0.45, 0.50, 0.70, 1) skutterudites was studied. Conversely to slowly cooled ingots, rapidly quenched ribbons show skutterudite as the main phase, suggesting that deep undercooling of the liquid prevents the nucleation of high temperature phases, such as (Fe,Ni)Sb and (Fe,Ni)Sb2. In as-quenched samples, a slightly out of equilibrium Sm content is revealed, which does not alter the position of the p/n boundary; nevertheless, it exerts an influence on crystallographic properties, such as the cell parameter and the shape of the Sb4 rings in the structure. As-quenched ribbons show a fine microstructure of the skutterudite phase (grain size of 2-20 μm), which only moderately coarsens after annealing at 873 K for 4 days. Vickers microhardness values (350-400 HV) of the skutterudite phase in as-quenched ribbons are affected by the presence of softer phases (i.e. Sb), which are homogeneously and finely dispersed within the sample. The skutterudite hardens after annealing as a consequence of a moderate grain growth, which limits the matrix effect due to the presence of additional phases.

  1. A trial of radiation dose prescription based on dose-cell survival formula

    International Nuclear Information System (INIS)

    Allen, E.P.

    1984-01-01

    Radiation treatment has been prescribed for 379 basal cell carcinomata on the basis of a selected equivalent single dose derived from the standard multi-target dose-cell survival formula using values of m = 2 and Do = 130 rads for orthovoltage x-rays. The results suggest that the approach provides a flexible and acceptable alternative to prescription by total dose or by Nominal Standard Dose. It is submitted that Total Dose is an inadequate expression of radiobiological effects: that the NSD and related systems are valuable measures of the ability of normal tissues to recover from radiation damage: and that a parallel measure of the degree of tumour depopulation has become necessary to allow further progress in alternative fractionation schedules

  2. Simulation of Shielding Effects on the Total Dose Observed in TDE of KISAT-1

    Directory of Open Access Journals (Sweden)

    Sung-Joon Kim

    2001-06-01

    Full Text Available The threshold voltage shift observed in TDE (Total Dose Experiment on board the KITSAT-1 is converted into dose (rad(SiO2 usinsg the result of laboratory calibration with Co-60 gamma ray source in KAERI (Korea Atomic Energy Research Institute. Simulation using the NASA radiation model of geomagnetosphere verifies that the dose difference between RADFET1 and RADFET3 observed on KITSAT-1 comes from the difference in shielding thickness at the position of these RADFETs.

  3. Responses of some normal tissues to low doses of γ-radiation

    International Nuclear Information System (INIS)

    Withers, H.R.

    1975-01-01

    The response of four normal tissues to low doses of γ-radiation was measured in mice using three indirect methods. The survival curves for cells of the tissues studied (colon, jejunum, testis and haemoleucopoietic system) may be exponential over an uncertain dose range (from zero to between 100 to 230 rad), the slope being about one third of that in the high-dose region. Some of the uncertainties in the data probably reflect variations in age-density distribution. (author)

  4. The rad2 mutation affects the molecular nature of UV and acridine-mustard-induced mutations in the ADE2 gene of Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Ivanov, E.L.; Kovaltzova, S.V.; Kassinova, G.V.; Gracheva, L.M.; Korolev, V.G.; Zakharov, I.A.

    1986-01-01

    The authors have studied the molecular nature of ade2 mutations induced by UV light and bifunctional acridine-mustard (BAM) in wild-type (RAD) and in excision-deficient (rad2) strains of the yeast, Saccharomyces cerevisiae. In the RAD strain, UV causes 45% GC → AT transitions among all mutations; in the rad2 strain this value is 77%. BAM was shown to be highly specific for frameshift mutagenesis: 60% frameshifts in the RAD strain, and as many as 84% frameshifts in the rad2 strain were induced. Therefore, the rad2 mutation affects the specificity of UV- and BAM-induced mutagenesis in yeast. Experimental data agree with the view that the majority of mutations in the RAD strain are induced by a prereplicative mechanism, whereas mutations in the rad2 strain are predominantly postreplicative events. (Auth.)

  5. Characterization of a fully resonant, 1-MHz, 25-watt, DC/DC converter fabricated in a rad-hard BiCMOS/high-voltage process

    International Nuclear Information System (INIS)

    Titus, J.L.; Gehlhausen, M.A.; Desko, J.C. Jr.; Nguyen, T.T.; Roberts, D.J.; Shibib, M.A.; Hollenbach, K.E.

    1995-01-01

    This paper presents the characterization of a DC/DC converter prototype when its power integrated circuit (PIC) chip is exposed to total dose, dose rate, neutron, and heavy ion environments. This fully resonant, 1-MHZ, 25-Watt, DC/DC converter is composed of a brassboard, populated with input/output filters, isolation transformers, output rectifier, capacitors, resistors, and PIC chip, integrating the primary-side control circuitry, secondary-side control circuitry, power switch, gate-drive circuitry, and voltage references. The brassboard is built using commercial off-the-shelf components; and the PIC chip is fabricated using AT and T's rad-hard, bipolar complementary metal-oxide semiconductor (BiCMOS)/high-voltage process. The intent of this paper is to demonstrate that the PIC chip is fabricated with a radiation-hardened process and to demonstrate that various analog, digital, and power functions can be effectively integrated

  6. Rad-hard electronics study for SSC detectors

    International Nuclear Information System (INIS)

    Ekenberg, T.; Dawson, J.; Stevens, A.; Haberichter, W.

    1991-01-01

    The radiation environment in a SSC detector operating at a luminosity of 10 33 cm -2 s -1 will put stringent requirements on radiation hardness of the electronics. Over the expected 10 year life-time of a large detector, ionizing radiation doses of up to 20 MRad and neutron fluences of 10 16 neutrons/cm 2 are projected. At a luminosity of 10 34 cm -2 s -1 even higher total doses are expected. the effect of this environment have been simulated by exposing CMOS/bulk and CMOS/SOS devices from monolithic processes to neutrons and ionizing radiation. leakage currents, noise variations, and DC characteristics have been measured before and after exposure in order to evaluate the effects of the irradiations. As expected the device characteristics remained virtually unchanged by neutron irradiation, while ionizing radiation caused moderate degradation of performance. 5 refs., 6 figs

  7. Development and application of the Chinese adult female computational phantom Rad-HUMAN

    International Nuclear Information System (INIS)

    Wu, Yican; Cheng, Mengyun; Wang, Wen; Fan, Yanchang; Zhao, Kai; He, Tao; Pei, Xi; Shang, Leiming; Chen, Chaobin; Long, Pengcheng; Cao, Ruifen; Wang, Guozhong; Zhou, Shaoheng; Yu, Shengpeng; Hu, Liqin; Zeng, Q.

    2013-01-01

    Rad-HUMAN is a whole-body numerical phantom of a Chinese adult woman which contains 46 organs and tissues and was created by MCAM6 software using the color photographs of the Chinese Visible Human dataset. This dataset was obtained from a 22-year old Chinese female cadaver judged to represent normal human anatomy as much as possible. The density and elemental composition recommended in the ICRP Publication 89 and in the ICRU report 44 were assigned to the organ and tissue in Rad-HUMAN for radiation protection purpose. The last step was to implement the anatomical data into a Monte Carlo code. Rad-HUMAN contains more than 28.8 billion tiny volume units, which produces an accurately whole-body numerical phantom of a Chinese adult female

  8. Comparison of Danish dichotomous and BI-RADS classifications of mammographic density

    DEFF Research Database (Denmark)

    Hodge, Rebecca; Hellmann, Sophie Sell; von Euler-Chelpin, My

    2014-01-01

    BACKGROUND: In the Copenhagen mammography screening program from 1991 to 2001, mammographic density was classified either as fatty or mixed/dense. This dichotomous mammographic density classification system is unique internationally, and has not been validated before. PURPOSE: To compare the Danish...... dichotomous mammographic density classification system from 1991 to 2001 with the density BI-RADS classifications, in an attempt to validate the Danish classification system. MATERIAL AND METHODS: The study sample consisted of 120 mammograms taken in Copenhagen in 1991-2001, which tested false positive......, and which were in 2012 re-assessed and classified according to the BI-RADS classification system. We calculated inter-rater agreement between the Danish dichotomous mammographic classification as fatty or mixed/dense and the four-level BI-RADS classification by the linear weighted Kappa statistic. RESULTS...

  9. Absorbed dose to the human adrenals from iodomethylnorcholesterol (I-131) NP-59: concise communication

    International Nuclear Information System (INIS)

    Carey, J.E.; Thrall, J.H.; Freitas, J.E.; Beierwaltes, W.H.

    1979-01-01

    During the past 2 yrs, adrenal uptake percentage values were measured in more than 40 patients, using an external counting technique. They suggest that the absorbed dose to the adrenals is significantly less than the 150 rads/mCi previously estimated using concentration values from animal adrenals. The measured combined uptake percentage for both adrenals ranged from 0.15% to 0.52% in 21 patients without evidence of adrenal disease, with a mean of 0.33% +- 0.1%; also from 0.22% to 1.5% in 22 patients with Cushing's disease, with a mean uptake of 0.78% +- 0.35%. The absorbed dose to the adrenals was estimated to be 25 rads/mCi for patients without evidence of adrenal disease, and 57 rads/mCi for patients with Cushing's disease. Both values are calculated for the respective mean uptake percentages by using the MIRD formalism

  10. Case of severe intestinal complications caused by high dose-rate intracavitary irradiation for cervical cancer

    Energy Technology Data Exchange (ETDEWEB)

    Koga, Kenji; Nishikawa, Kiyoshi; Matsuki, Kazuhiko; Watanabe, Katsushi

    1987-02-01

    A 46-year-old woman with severe intestinal complication caused by high dose-rate intracavitary irradiation is reported. She received radiation treatment of stage IIb cervical cancer between July 24 and September 26, 1984: a dose of 2400 rad to a point A concurrently with 2000 rad to the parametrium following 4000 rad to the whole pelvis. Eight months later she developed diarrhea and bloody stool. Barium enema study revealed a stenosis at 20 to 25 cm from the anal ring and romanoscopy oozing coagula at the same site. On November 29, 1985 transverse colostomy was performed because of continuing bloody stool and abdominal pain. On January 30, 1986 resection of the ileum and ileostomy were done because of the ileum perforation located 26 cm apart from the ileum end. Some discussion on the causes of this complication are made, suggesting that short length of a tandem and deep location of ovoids influence its cause.

  11. Dose measurements in laboratory of Physics department, University of Khartoum

    International Nuclear Information System (INIS)

    Hamid, Maria Mohammed

    1999-05-01

    Personal monitoring in University of Khartoum is being conducted using thermoluminescent dosimetry. The purpose of the study is to measure the dose of radiation in laboratory of Physics in physics department. TL phosphors LiF: Mg, Ti (card) and LiF Mg, Cu, P (GR-200) and mini-rad dosimeter are used to measure the dose in laboratory. The total dose for students form the laboratory bu using card, GR-200 and mini-rad dosimeter was found to be 2.2μ sv/year. 2.5 μ sv/year and 2.6 μ sv respectively, and for the teacher about 4.0 μ sv/year, 5.8 μ sv/year and 13.6 μ sv/year respectively, and for the dose near junk room about 3.9 μ sv/year, 2.9 μ sv/year and 2.8 μ sv/year by using card, GR-200 and mini-rad dosimeter respectively. There is just a background radiation in the main library and the applied nuclear.(Author)

  12. Determination of gamma ray doses suitable for mutation induction in garlic (Allium sativum L.)

    International Nuclear Information System (INIS)

    Al-Safadi, Bassam; Ayyoubi, Zouhair

    1993-04-01

    Garlic (Allium sativum L.) cloves were exposed to different doses of gamma radiation (Control, 100, 250, 500, 750, and 1000 rads). The cloves were planted in 4 replicates at Deer Alhajar station of the Dept. of Radiation Agriculture. Number of surviving plants was recorded at 2 months after planting and at harvest. Length of foliage was measured at harvest time and weight of cloves was taken two weeks after harvest. Visual readings in the field on plant shape and leaf color were also taken. The results indicated a negative effect of gamma radiation on plant survival especially at doses of 750 and 1000 rads where no plants survived until harvest. Plant length and clove weight were reduced even at 500 rad dose. Percentage of yellow and necrotic plants increased with increasing gamma ray dosage. No stimulation of plant growth was noticed as a result of irradiation with low doses of gamma rays. Treatment with 500 rads of gamma radiation was considered the best among tested doses for garlic mutagenesis (Using cloves) since it gave acceptable rate of survival and morphologic variation. (author). 14 refs., 4 figs

  13. Limiting values for the RBE of fission neutrons at low doses for life shortening in mice

    International Nuclear Information System (INIS)

    Storer, J.B.; Mitchell, T.J.

    1984-01-01

    The authors have analyzed recently published data on the effects of low doses of fission neutrons on the mean survival times of mice. The analysis for single-dose exposures was confined to doses of 20 rad or less, while for fractionated exposures only total doses of 80 rad or less were considered. They fitted the data to the frequently used power function model: life shortening = βD/sup γ/, where D is the radiation dose. They show that, at low doses per fraction, either the effects are not additive or the dose-effect curve for single exposures cannot show a greater negative curvature than about the 0.9 power of dose. Analysis of the data for γ rays showed that an exponent of 1.0 gave an acceptable fit. They conclude that at neutron doses of 20 rad or less the RBE for life shortening is constant and ranges from 13 to 22 depending on mouse strain and sex

  14. Carcinogenesis in mice after low doses and dose rates

    International Nuclear Information System (INIS)

    Ullrich, R.L.

    1979-01-01

    The results from the experimental systems reported here indicate that the dose-response curves for tumor induction in various tissues cannot be described by a single model. Furthermore, although the understanding of the mechanisms involved in different systems is incomplete, it is clear that very different mechanisms for induction are involved. For some tumors the mechanism of carcinogenesis may be mainly a result of direct effects on the target cell, perhaps involving one or more mutations. While induction may occur, in many instances, through such direct effects, the eventual expression of the tumor can be influenced by a variety of host factors including endocrine status, competence of the immune system, and kinetics of target and interacting cell populations. In other tumors, indirect effects may play a major role in the initiation or expression of tumors. Some of the hormone-modulated tumors would fall into this class. Despite the complexities of the experimental systems and the lack of understanding of the types of mechanisms involved, in nearly every example the tumorigenic effectiveness per rad of low-LET radiation tends to decrease with decreasing dose rate. For some tumor types the differences may be small or may appear only with very low dose rates, while for others the dose-rate effects may be large

  15. RadLex - German version: a radiological lexicon for indexing image and report information; RadLex - deutsche Version: Ein radiologisches Lexikon zur Indexierung von Bild- und Befunddaten

    Energy Technology Data Exchange (ETDEWEB)

    Marwede, D.; Lobsien, D.; Kahn, T. [Universitaetsklinikum Leipzig (Germany). Klinik und Poliklinik fuer Diagnostische und Interventionelle Radiologie; Daumke, P.; Marko, K.; Schulz, S. [Universitaetsklinikum Freiburg (Germany). Inst. fuer Medizinische Biometrie und Medizinische Informatik

    2009-01-15

    Purpose: Since 2003 the Radiological Society of North America (RSNA) has been developing a lexicon of standardized radiological terms (RadLex) intended to support the structured reporting of imaging observations and the indexing of teaching cases. The aim of this study was to translate the first version of the lexicon (1 - 2007) into German and to implement a language-independent online term browser. Materials and Methods: RadLex version 1 - 2007 contains 6303 terms in nine main categories. Two radiologists independently translated the lexicon using medical dictionaries. Terms translated differently were revised and translated by consensus. For the development of an online term browser, a text processing algorithm called morphosemantic indexing was used which splits up words into small semantic units and compares those units to language-specific subword thesauri. Results: In total 6240 of 6303 terms (99 %) were translated. Of those terms 3965 were German, 1893 were Latin, 359 were multilingual, and 23 were English terms that are also used in German and were therefore maintained. The online term browser supports a language-independent term search in RadLex (German/English) and other common medical terminology (e.g., ICD 10). The term browser displays term hierarchies and translations in different frames and the complexity of the result lists can be adapted by the user. Conclusion: RadLex version 1 - 2007 developed by the RSNA is now available in German and can be accessed online through a term browser with an efficient search function. This is an important precondition for the future comparison of national and international indexed radiological examination results and the interoperability between digital teaching resources. (orig.)

  16. Roles of Rad51 protein in homologous recombination in mammalian cells: relation with repair, replication and cell cycle

    International Nuclear Information System (INIS)

    Lambert, S.

    2001-01-01

    Homologous recombination (HR) is a fundamental process, allowing a faithful repair. In mammalian, MmRAD51, which is the homologue of Saccharomyces cerevisiae ScRAD51 key protein for HR, is an essential gene. This work is based on the characterisation of viable hyper and hypo-recombinant cell lines specifically affected in the Rad51 pathway. By expressing wild type and dominant negative forms of MmRad51, we demonstrated that Rad51 pathway participates to the repair by HR to induced DNA damages. However, inhibition of the Rad 51 pathway does not affect cell viability, spontaneously or after irradiation, whereas, radiation induced HR is inhibited. In the presence of DNA damages during late S and G2/M phase, inhibition of Rad51 pathway induced chromosomal aberrations, leading to a transient arrest in mitosis. This arrest is associated with an increased of cell death. However, a fraction of cells can escape from this transient arrest by forming tetraploid cells, associated with an absence of chromalid separation. Thus, in response to impaired Rad51 pathway, mitotic checkpoints seems to play an essential role. In line with this, we showed that the essential function of Rad51 is p53-dependent, which is in agreement with the role of p53 in tetraploidy inhibition. Our results suggest that the Rad51 protein could participate to the control of mitotic checkpoints and thus to the maintenance of genetic stability. This function could involve other Rad51 partners such as the tumour suppressors BRCA1, BRCA2 and p53. (author) [fr

  17. Diagnostic value of breast ultrasound in mammography BI-RADS 0 and clinically indeterminate or suspicious of malignancy breast lesions

    Directory of Open Access Journals (Sweden)

    Dobrosavljević Aleksandar

    2016-01-01

    Full Text Available Background/Aim. Not only that ultrasound makes the difference between cystic and solid changes in breast tissue, as it was the case at the beginning of its use, but it also makes the differential diagnosis in terms of benign-malignant. The aim of this study was to assess the role of sonography in the diagnosis of palpable breast masses according to the American College of Radiology Ultrasonographic Breast Imaging Reporting and Data System (BI-RADS and to correlate the BI-RADS 4 and BI-RADS 5 category with pathohistological findings. Methods. A retrospective study was conducted with the breast sonograms of 30 women presented with palpable breast masses found to be mammography category BI-RADS 0 and ultrasonographic BI-RADS categories 4 and 5. The sonographic categories were correlated with pathohistological findings. Results. Surgical biopsy in 30 masses revealed: malignancy (56.7%, fibroadenoma (26.7%, fibrocystic dysplasia with/without atypia (10%, lipoma (3.3% and intramammary lymph node (3.3%. Correlation between BI-RADS categories and pathohistological findings was found (p < 0.05. All BI-RADS 5 masses were malignant, while in BI-RADS 4A category fibroadenomas dominated. A total of 53.8% of all benign lesions were found in women 49 years of age or younger as compared with 35.3% of all malignancies in this group (p < 0.05. Conclusion. Ultrasonography BI-RADS improved classification of breast masses. The ultrasound BI-RADS 4 (A, B, C and BI-RADS 5 lesions should be worked-up with biopsy.

  18. A reliability-risk modelling of nuclear rad-waste facilities

    International Nuclear Information System (INIS)

    Lehmann, P.H.; El-Bassioni, A.A.

    1975-01-01

    Rad-waste disposal systems of nuclear power sites are designed and operated to collect, delay, contain, and concentrate radioactive wastes from reactor plant processes such that on-site and off-site exposures to radiation are well below permissible limits. To assist the designer in achieving minimum release/exposure goals, a computerized reliability-risk model has been developed to simulate the rad-waste system. The objectives of the model are to furnish a practical tool for quantifying the effects of changes in system configuration, operation, and equipment, and for the identification of weak segments in the system design. Primarily, the model comprises a marriage of system analysis, reliability analysis, and release-risk assessment. Provisions have been included in the model to permit the optimization of the system design subject to constraints on cost and rad-releases. The system analysis phase involves the preparation of a physical and functional description of the rad-waste facility accompanied by the formation of a system tree diagram. The reliability analysis phase embodies the formulation of appropriate reliability models and the collection of model parameters. Release-risk assessment constitutes the analytical basis whereupon further system and reliability analyses may be warranted. Release-risk represents the potential for release of radioactivity and is defined as the product of an element's unreliability at time, t, and the radioactivity available for release in time interval, Δt. A computer code (RARISK) has been written to simulate the tree diagram of the rad-waste system. Reliability and release-risk results have been generated for cases which examined the process flow paths of typical rad-waste systems, the effects of repair and standby, the variations of equipment failure and repair rates, and changes in system configurations. The essential feature of this model is that a complex system like the rad-waste facility can be easily decomposed into its

  19. Identification of a deoxyribonuclease controlled by the rad52 gene of Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Chow, T.Y.K.; Resnick, M.A.

    1983-01-01

    We have examined deoxyribonuclease levels in extracts of wild-type and rad52 mutants and have observed no significant differences. However, major differences were observed when we employed anti-serum raised against a purified single strand DNA-binding endoexonuclease from Neurospora crassa. As much as sixty percent of the alkaline deoxyribonuclease in wild-type extracts exhibited immunocrossreactivity, whereas none was found in extracts from rad52 strains. This DNase activity was also followed through meiosis; maximum activity was observed in wild-type cells, at a time corresponding to an early stage of premeiotic DNA-synthesis and commitment to recombination. 14 references, 4 figures, 1 table

  20. RadSTraM: Radiological Source Tracking and Monitoring, Phase II Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Tracy A [ORNL; Walker, Randy M [ORNL; Hill, David E [ORNL; Gross, Ian G [ORNL; Smith, Cyrus M [ORNL; Abercrombie, Robert K [ORNL

    2008-12-01

    This report focuses on the technical information gained from the Radiological Source Tracking and Monitoring (RadSTraM) Phase II investigation and its implications. The intent of the RadSTraM project was to determine the feasibility of tracking radioactive materials in commerce, particularly International Atomic Energy Agency (IAEA) Category 3 and 4 materials. Specifically, Phase II of the project addressed tracking radiological medical isotopes in commerce. These categories of materials are susceptible to loss or theft but the problem is not being addressed by other agencies.

  1. RadSTraM: Radiological Source Tracking and Monitoring, Phase II Final Report

    International Nuclear Information System (INIS)

    Warren, Tracy A.; Walker, Randy M.; Hill, David E.; Gross, Ian G.; Smith, Cyrus M.; Abercrombie, Robert K.

    2008-01-01

    This report focuses on the technical information gained from the Radiological Source Tracking and Monitoring (RadSTraM) Phase II investigation and its implications. The intent of the RadSTraM project was to determine the feasibility of tracking radioactive materials in commerce, particularly International Atomic Energy Agency (IAEA) Category 3 and 4 materials. Specifically, Phase II of the project addressed tracking radiological medical isotopes in commerce. These categories of materials are susceptible to loss or theft but the problem is not being addressed by other agencies

  2. RadShield: semiautomated shielding design using a floor plan driven graphical user interface.

    Science.gov (United States)

    DeLorenzo, Matthew C; Wu, Dee H; Yang, Kai; Rutel, Isaac B

    2016-09-08

    The purpose of this study was to introduce and describe the development of RadShield, a Java-based graphical user interface (GUI), which provides a base design that uniquely performs thorough, spatially distributed calculations at many points and reports the maximum air-kerma rate and barrier thickness for each barrier pursuant to NCRP Report 147 methodology. Semiautomated shielding design calculations are validated by two approaches: a geometry-based approach and a manual approach. A series of geometry-based equations were derived giv-ing the maximum air-kerma rate magnitude and location through a first derivative root finding approach. The second approach consisted of comparing RadShield results with those found by manual shielding design by an American Board of Radiology (ABR)-certified medical physicist for two clinical room situations: two adjacent catheterization labs, and a radiographic and fluoroscopic (R&F) exam room. RadShield's efficacy in finding the maximum air-kerma rate was compared against the geometry-based approach and the overall shielding recommendations by RadShield were compared against the medical physicist's shielding results. Percentage errors between the geometry-based approach and RadShield's approach in finding the magnitude and location of the maximum air-kerma rate was within 0.00124% and 14 mm. RadShield's barrier thickness calculations were found to be within 0.156 mm lead (Pb) and 0.150 mm lead (Pb) for the adjacent catheteriza-tion labs and R&F room examples, respectively. However, within the R&F room example, differences in locating the most sensitive calculation point on the floor plan for one of the barriers was not considered in the medical physicist's calculation and was revealed by the RadShield calculations. RadShield is shown to accurately find the maximum values of air-kerma rate and barrier thickness using NCRP Report 147 methodology. Visual inspection alone of the 2D X-ray exam distribution by a medical physicist may not

  3. Conduction electron spin resonance in the α-Yb1−xFexAlB4 (0 ⩽ x ⩽ 0.50) and α-LuAlB4 compounds

    International Nuclear Information System (INIS)

    Holanda, L M; Lesseux, G G; Urbano, R R; Rettori, C; Pagliuso, P G; Magnavita, E T; Ribeiro, R A; Nakatsuji, S; Kuga, K; Fisk, Z; Oseroff, S B

    2015-01-01

    β-YbAlB 4 has become one of the most studied heavy fermion systems since its discovery due to its remarkable physical properties. This system is the first reported Yb-based heavy-fermion superconductor (HFS) for which the low-T superconducting state emerges from a non-fermi-liquid (NFL) normal state associated with quantum criticality Nakatsuji et al 2008 Nature 4 603. Additionally, it presents a striking and unprecedented electron spin resonance (ESR) signal which behaves as a conduction electron spin resonance (CESR) at high temperatures and acquires features of the Yb 3+ local moment ESR at low temperatures. The latter, also named Kondo quasiparticles spin resonance (KQSR), has been defined as a 4f-ce strongly coupled ESR mode that behaves as a local probe of the Kondo quasiparticles in a quantum critical regime, Holanda et al 2011 Phys. Rev. Lett. 107 026402. Interestingly, β-YbAlB 4 possesses a previously known structural variant, namely the α-YbAlB 4 , phase which is a paramagnetic Fermi liquid (FL) at low temperatures Macaluso et al 2007 Chem. Mater. 19 1918. However, it has been recently suggested that the α-YbAlB 4 phase may be tuned to NFL behavior and/or magnetic ordering as the compound is doped with Fe. Here we report ESR studies on the α-Yb 1−x Fe x AlB 4 (0 ⩽ x ⩽ 0.50) series as well as on the reference compound α-LuAlB 4 . For all measured samples, the observed ESR signal behaves as a CESR in the entire temperature range (10 K ≲ T ≲ 300 K) in clear contrast with what has been observed for β-YbAlB 4 . This striking result indicates that the proximity to a quantum critical point is crucial to the occurrence of a KQSR signal. (paper)

  4. Germline variants in MRE11/RAD50/NBN complex genes in childhood leukemia

    International Nuclear Information System (INIS)

    Mosor, Maria; Ziółkowska-Suchanek, Iwona; Nowicka, Karina; Dzikiewicz-Krawczyk, Agnieszka; Januszkiewicz–Lewandowska, Danuta; Nowak, Jerzy

    2013-01-01

    The MRE11, RAD50, and NBN genes encode proteins of the MRE11-RAD50-NBN (MRN) complex involved in cellular response to DNA damage and the maintenance of genome stability. In our previous study we showed that the germline p.I171V mutation in NBN may be considered as a risk factor in the development of childhood acute lymphoblastic leukemia (ALL) and some specific haplotypes of that gene may be associated with childhood leukemia. These findings raise important questions about the role of mutations in others genes of the MRN complex in childhood leukemia. The aim of this study was to answer the question whether MRE11 and RAD50 alterations may be associated with childhood ALL or AML. We estimated the frequency of constitutional mutations and polymorphisms in selected regions of MRE11, RAD50, and NBN in the group of 220 children diagnosed with childhood leukemias and controls (n=504/2200). The analysis was performed by specific amplification of region of interest by PCR and followed by multi-temperature single-strand conformation polymorphism (PCR-MSSCP) technique. We performed two molecular tests to examine any potential function of the detected the c.551+19G>A SNP in RAD50 gene. To our knowledge, this is the first analysis of the MRE11, RAD50 and NBN genes in childhood leukemia. The frequency of either the AA genotype or A allele of RAD50-rs17166050 were significantly different in controls compared to leukemia group (ALL+AML) (p<0.0019 and p<0.0019, respectively). The cDNA analysis of AA or GA genotypes carriers has not revealed evidence of splicing abnormality of RAD50 pre-mRNA. We measured the allelic-specific expression of G and A alleles at c.551+19G>A and the statistically significant overexpression of the G allele has been observed. Additionally we confirmed the higher incidence of the p.I171V mutation in the leukemia group (7/220) than among controls (12/2400) (p<0.0001). The formerly reported sequence variants in the RAD50 and MRE11 gene may not constitute a

  5. 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

  6. Eye lens exposure to medical staff performing electrophysiology procedures: dose assessment and correlation to patient dose

    International Nuclear Information System (INIS)

    Ciraj-Bjelac, Olivera; Bozovic, Predrag; Arandjic, Danijela; Antic, Vojislav; Selakovic, Jovana; Pavlovic, Sinisa

    2016-01-01

    The purpose of this study was to assess the patient exposure and staff eye dose levels during implantation procedures for all types of pacemaker therapy devices performed under fluoroscopic guidance and to investigate potential correlation between patients and staff dose levels. The mean eye dose during pacemaker/defibrillator implementation was 12 μSv for the first operator, 8.7 μSv for the second operator/nurse and 0.50 μSv for radiographer. Corresponding values for cardiac re-synchronisation therapy procedures were 30, 26 and 2.0 μSv, respectively. Significant (p < 0.01) correlation between the eye dose and the kerma-area product was found for the first operator and radiographers, but not for other staff categories. The study revealed eye dose per procedure and eye dose normalised to patient dose indices for different staff categories and provided an input for radiation protection in electrophysiology procedures. (authors)

  7. A simple ionizing radiation spectrometer/dosimeter based on radiation sensing field effect transistors (RadFETs)

    International Nuclear Information System (INIS)

    Moreno, D.J.; Hughes, R.C.; Jenkins, M.W.; Drumm, C.R.

    1997-01-01

    This paper reports on the processing steps in a silicon foundry leading to improved performance of the Radiation Sensing Field Effect Transistor (RadFET) and the use of multiple RadFETs in a handheld, battery operated, combination spectrometer/dosimeter

  8. Cohesin Rad21 Mediates Loss of Heterozygosity and Is Upregulated via Wnt Promoting Transcriptional Dysregulation in Gastrointestinal Tumors

    Directory of Open Access Journals (Sweden)

    Huiling Xu

    2014-12-01

    Full Text Available Summary: Loss of heterozygosity (LOH of the adenomatous polyposis coli (APC gene triggers a series of molecular events leading to intestinal adenomagenesis. Haploinsufficiency of the cohesin Rad21 influences multiple initiating events in colorectal cancer (CRC. We identify Rad21 as a gatekeeper of LOH and a β-catenin target gene and provide evidence that Wnt pathway activation drives RAD21 expression in human CRC. Genome-wide analyses identified Rad21 as a key transcriptional regulator of critical CRC genes and long interspersed element (LINE-1 or L1 retrotransposons. Elevated RAD21 expression tracks with reactivation of L1 expression in human sporadic CRC, implicating cohesin-mediated L1 expression in global genomic instability and gene dysregulation in cancer. : Rad21 holds the cohesin complex together as part of its role in chromosome partitioning and DNA repair. Xu et al. identify Rad21 as a key mediator of Apc gene heterozygous loss, the event initiating intestinal tumorigenesis. The subsequent activation of the Wnt pathway further induces Rad21, global gene dysregulation, chromosome instability, and pervasive retrotransposon activation.

  9. A novel RAD21 variant associated with intrafamilial phenotypic variation in Cornelia de Lange syndrome - review of the literature

    DEFF Research Database (Denmark)

    Boyle, M I; Jespersgaard, C; Nazaryan-Petersen, Lusine

    2017-01-01

    In a patient with CdLS (IV.16) we identifed a novel single basepair deletion (c.704delG) in RAD21, which encodes a cohesin pathway protein. The variant is predicted to result in a premature stop codon [p.(Ser235Ilefs*19)] and hereby would have a deleterious effect. RAD21 variants have previously ...

  10. A dose to curie conversion methodology

    International Nuclear Information System (INIS)

    Stowe, P.A.

    1987-01-01

    Development of the computer code RadCAT (Radioactive waste Classification And Tracking) has led to the development of a simple dose rate to curie content conversion methodology for containers with internally distributed radioactive material. It was determined early on that, if possible, the computerized dose rate to curie evaluation model employed in RadCAT should yield the same results as the hand method utilized and specified in plant procedures. A review of current industry practices indicated two distinct types of computational methodologies are presently in use. The most common methods are computer based calculations utilizing complex mathematical models specifically established for various containers geometries. This type of evaluation is tedious, however, and does not lend itself to repetition by hand. The second method of evaluation, therefore, is simplified expressions that sacrifice accuracy for ease of computation, and generally over estimate container curie content. To meet the aforementioned criterion current computer based models were deemed unacceptably complex and hand computational methods to be too inaccurate for serious consideration. The contact dose rate/curie content analysis methodology presented herein provides an equation that is easy to use in hand calculations yet provides accuracy equivalent to other computer based computations

  11. RTOG 0913: A Phase 1 Study of Daily Everolimus (RAD001) in Combination With Radiation Therapy and Temozolomide in Patients With Newly Diagnosed Glioblastoma

    Energy Technology Data Exchange (ETDEWEB)

    Chinnaiyan, Prakash, E-mail: prakash.chinnaiyan@moffitt.org [Department of Radiation Oncology, Experimental Therapeutics and Cancer Imaging and Metabolism, H. Lee Moffitt Cancer Center, Tampa, Florida (United States); Won, Minhee [Radiation Therapy Oncology Group, Philadelphia, Pennsylvania (United States); Wen, Patrick Y. [Center for Neuro-Oncology, Dana-Farber/Brigham and Women' s Cancer Center, Boston, Massachusetts (United States); Rojiani, Amyn M. [Department of Pathology, Medical College of Georgia, Augusta, Georgia (United States); Wendland, Merideth [Radiation Oncology, US Oncology-Willamette Valley Cancer Institute, Eugene, Oregon (United States); Dipetrillo, Thomas A. [Department of Radiation Oncology, Rhode Island Hospital, Providence, Rhode Island (United States); Corn, Benjamin W. [Department of Radiation Oncology, Tel Aviv Medical Center, Tel Aviv (Israel); Mehta, Minesh P. [Department of Radiation Oncology, University of Maryland, Baltimore, Maryland (United States)

    2013-08-01

    Purpose: To determine the safety of the mammalian target of rapamycin inhibitor everolimus (RAD001) administered daily with concurrent radiation and temozolomide in newly diagnosed glioblastoma patients. Methods and Materials: Everolimus was administered daily with concurrent radiation (60 Gy in 30 fractions) and temozolomide (75 mg/m{sup 2} per day). Everolimus was escalated from 2.5 mg/d (dose level 1) to 5 mg/d (dose level 2) to 10 mg/d (dose level 3). Adjuvant temozolomide was delivered at 150 to 200 mg/m{sup 2} on days 1 to 5, every 28 days, for up to 12 cycles, with concurrent everolimus at the previously established daily dose of 10 mg/d. Dose escalation continued if a dose level produced dose-limiting toxicities (DLTs) in fewer than 3 of the first 6 evaluable patients. Results: Between October 28, 2010, and July 2, 2012, the Radiation Therapy Oncology Group 0913 protocol initially registered a total of 35 patients, with 25 patients successfully meeting enrollment criteria receiving the drug and evaluable for toxicity. Everolimus was successfully escalated to the predetermined maximum tolerated dose of 10 mg/d. Two of the first 6 eligible patients had a DLT at each dose level. DLTs included gait disturbance, febrile neutropenia, rash, fatigue, thrombocytopenia, hypoxia, ear pain, headache, and mucositis. Other common toxicities were grade 1 or 2 hypercholesterolemia and hypertriglyceridemia. At the time of analysis, there was 1 death reported, which was attributed to tumor progression. Conclusions: Daily oral everolimus (10 mg) combined with both concurrent radiation and temozolomide followed by adjuvant temozolomide is well tolerated, with an acceptable toxicity profile. A randomized phase 2 clinical trial with mandatory correlative biomarker analysis is currently under way, designed to both determine the efficacy of this regimen and identify molecular determinants of response.

  12. The RadGenomics project. Prediction for radio-susceptibility of individuals with genetic predisposition

    International Nuclear Information System (INIS)

    Imai, Takashi

    2003-01-01

    The ultimate goal of our project, named RadGenomics, is to elucidate the heterogeneity of the response to ionizing radiation arising from genetic variation among individuals, for the purpose of developing personalized radiation therapy regimens for cancer patients. Cancer patients exhibit patient-to-patient variability in normal tissue reactions after radiotherapy. Several observations support the hypothesis that the radiosensitivity of normal tissue is influenced by genetic factors. The rapid progression of human genome sequencing and the recent development of new technologies in molecular biology are providing new opportunities for elucidating the genetic basis of individual differences in susceptibility to radiation exposure. The development of a sufficiently robust, predictive assay enabling individual dose adjustment would improve the outcome of radiation therapy in patients. Our strategy for identification of DNA polymorphisms that contribute to the individual radiosensitivity is as follows. First, we have been categorizing DNA samples obtained from cancer patients, who have been kindly introduced to us through many collaborators, according to their clinical characteristics including the method and effect of treatment and side effects as scored by toxicity criteria, and also the result of an in vitro radiosensitivity assay, e.g., the micronuclei assay of their lymphocytes. Second, we have identified candidate genes for genotyping mainly by using our custom-designed oligonucleotide array with RNA samples, in which the probes were obtained from more than 40 cancer and 3 fibroblast cell lines whose radiosensitivity level was quite heterogeneous. We have also been studying the modification of proteins after irradiation of cells which may be caused by mainly phosphorylation or dephosphorylation, using mass spectrometry. Genes encoding the modified proteins and/or other proteins with which they interact such as specific protein kinases and phosphatases are also

  13. Influence of different inhibitors on the activity of the RAD54 dependent step of DNA repair in Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Siede, W.; Obermaier, S.; Eckhardt, F.

    1985-01-01

    The recombinagenic pathway of DNA repair in yeast was characterized by the effect of different inhibitors on the temperature-dependent survival after ..gamma..-irradiation in haploid cells of the thermoconditional mutant rad54-3. Blocking protein synthesis with cycloheximide in replicating cells caused partial inhibition of the RAD54 dependent function but some repair activity remained detectable. This indicates that ..gamma..-rays can induce RAD54 activity above some constitutive level of function. Inhibition of DNA replication by hydroxyurea efficiently blocked the RAD54 dependent function in stationary-phase cells but not in logarithmic-phase cells. In logarithmic-phase cells, the authors found a strong inhibitory effect of caffeine on the RAD54 mediated repair process.

  14. Phototransfer method of determining archaeological dose of pottery sherds

    International Nuclear Information System (INIS)

    Sasidharan, R.; Sunta, C.M.; Nambi, K.S.V.

    1978-01-01

    The method of PTTL (phototransfer thermoluminescence) dating works satisfactorily over a very wide range of archaeological doses and the upper limit seems to be around 4000 rads. The first TL peak generally occurs at 65deg C or 100deg C in different varieties of quartz and both seem to be satisfactory for PTTL dating if the reading procedure is standardised to take care of the fast fading of these peaks at room temperature. (author)

  15. Compensatory role for Rad52 during recombinational repair in Ustilago maydis

    DEFF Research Database (Denmark)

    Kojic, Milorad; Mao, Ninghui; Zhou, Qingwen

    2008-01-01

    A single Rad52-related protein is evident by blast analysis of the Ustilago maydis genome database. Mutants created by disruption of the structural gene exhibited few discernible defects in resistance to UV, ionizing radiation, chemical alkylating or cross-linking agents. No deficiency was noted...

  16. Fission yeast shelterin regulates DNA polymerases and Rad3(ATR kinase to limit telomere extension.

    Directory of Open Access Journals (Sweden)

    Ya-Ting Chang

    2013-11-01

    Full Text Available Studies in fission yeast have previously identified evolutionarily conserved shelterin and Stn1-Ten1 complexes, and established Rad3(ATR/Tel1(ATM-dependent phosphorylation of the shelterin subunit Ccq1 at Thr93 as the critical post-translational modification for telomerase recruitment to telomeres. Furthermore, shelterin subunits Poz1, Rap1 and Taz1 have been identified as negative regulators of Thr93 phosphorylation and telomerase recruitment. However, it remained unclear how telomere maintenance is dynamically regulated during the cell cycle. Thus, we investigated how loss of Poz1, Rap1 and Taz1 affects cell cycle regulation of Ccq1 Thr93 phosphorylation and telomere association of telomerase (Trt1(TERT, DNA polymerases, Replication Protein A (RPA complex, Rad3(ATR-Rad26(ATRIP checkpoint kinase complex, Tel1(ATM kinase, shelterin subunits (Tpz1, Ccq1 and Poz1 and Stn1. We further investigated how telomere shortening, caused by trt1Δ or catalytically dead Trt1-D743A, affects cell cycle-regulated telomere association of telomerase and DNA polymerases. These analyses established that fission yeast shelterin maintains telomere length homeostasis by coordinating the differential arrival of leading (Polε and lagging (Polα strand DNA polymerases at telomeres to modulate Rad3(ATR association, Ccq1 Thr93 phosphorylation and telomerase recruitment.

  17. RPA and Rad51 constitute a cell intrinsic mechanism to protect the cytosol from self DNA.

    Science.gov (United States)

    Wolf, Christine; Rapp, Alexander; Berndt, Nicole; Staroske, Wolfgang; Schuster, Max; Dobrick-Mattheuer, Manuela; Kretschmer, Stefanie; König, Nadja; Kurth, Thomas; Wieczorek, Dagmar; Kast, Karin; Cardoso, M Cristina; Günther, Claudia; Lee-Kirsch, Min Ae

    2016-05-27

    Immune recognition of cytosolic DNA represents a central antiviral defence mechanism. Within the host, short single-stranded DNA (ssDNA) continuously arises during the repair of DNA damage induced by endogenous and environmental genotoxic stress. Here we show that short ssDNA traverses the nuclear membrane, but is drawn into the nucleus by binding to the DNA replication and repair factors RPA and Rad51. Knockdown of RPA and Rad51 enhances cytosolic leakage of ssDNA resulting in cGAS-dependent type I IFN activation. Mutations in the exonuclease TREX1 cause type I IFN-dependent autoinflammation and autoimmunity. We demonstrate that TREX1 is anchored within the outer nuclear membrane to ensure immediate degradation of ssDNA leaking into the cytosol. In TREX1-deficient fibroblasts, accumulating ssDNA causes exhaustion of RPA and Rad51 resulting in replication stress and activation of p53 and type I IFN. Thus, the ssDNA-binding capacity of RPA and Rad51 constitutes a cell intrinsic mechanism to protect the cytosol from self DNA.

  18. Caffeine stabilizes Cdc25 independently of Rad3 in S chizosaccharomyces pombe contributing to checkpoint override

    Science.gov (United States)

    Alao, John P; Sjölander, Johanna J; Baar, Juliane; Özbaki-Yagan, Nejla; Kakoschky, Bianca; Sunnerhagen, Per

    2014-01-01

    Cdc25 is required for Cdc2 dephosphorylation and is thus essential for cell cycle progression. Checkpoint activation requires dual inhibition of Cdc25 and Cdc2 in a Rad3-dependent manner. Caffeine is believed to override activation of the replication and DNA damage checkpoints by inhibiting Rad3-related proteins in both S chizosaccharomyces pombe and mammalian cells. In this study, we have investigated the impact of caffeine on Cdc25 stability, cell cycle progression and checkpoint override. Caffeine induced Cdc25 accumulation in S . pombe independently of Rad3. Caffeine delayed cell cycle progression under normal conditions but advanced mitosis in cells treated with replication inhibitors and DNA-damaging agents. In the absence of Cdc25, caffeine inhibited cell cycle progression even in the presence of hydroxyurea or phleomycin. Caffeine induces Cdc25 accumulation in S . pombe by suppressing its degradation independently of Rad3. The induction of Cdc25 accumulation was not associated with accelerated progression through mitosis, but rather with delayed progression through cytokinesis. Caffeine-induced Cdc25 accumulation appears to underlie its ability to override cell cycle checkpoints. The impact of Cdc25 accumulation on cell cycle progression is attenuated by Srk1 and Mad2. Together our findings suggest that caffeine overrides checkpoint enforcement by inducing the inappropriate nuclear localization of Cdc25. PMID:24666325

  19. Mammalian RAD52 Functions in Break-Induced Replication Repair of Collapsed DNA Replication Forks

    DEFF Research Database (Denmark)

    Sotiriou, Sotirios K; Kamileri, Irene; Lugli, Natalia

    2016-01-01

    Human cancers are characterized by the presence of oncogene-induced DNA replication stress (DRS), making them dependent on repair pathways such as break-induced replication (BIR) for damaged DNA replication forks. To better understand BIR, we performed a targeted siRNA screen for genes whose...... RAD52 facilitates repair of collapsed DNA replication forks in cancer cells....

  20. Acorrelation study between histological results and thyroid ultrasound findings. The TI-RADS classification.

    Science.gov (United States)

    García-Moncó Fernández, Carlos; Serrano-Moreno, Clara; Donnay-Candil, Sergio; Carrero-Alvaro, Juan

    2018-04-01

    There are several classifications based on thyroid ultrasound for selecting suspected malignant thyroid nodules. The Thyroid Imaging Reporting and Data System (TI-RADS) classification proposed by Horvath in 2009 includes 6 categories. To assess the sensitivity of the TI-RADS classification for diagnosing thyroid nodules. A retrospective study of all patients who underwent thyroidectomy at our hospital (n=263) from September 2013 to December 2015. After thyroidectomy, histological results were correlated to the ultrasound findings reported. Of the 263 study patients, 75 (28.5%) were diagnosed with thyroid cancer and 188 (71.5%) with benign disease. Correlation of histological results with preoperative ultrasound reports showed an initial sensitivity of 65%. After excluding 15 patients diagnosed with occult microcarcinoma, sensitivity increased to 81.6%. The ultrasound images from 11 false negatives cases were then reassessed by a radiologist who knew histological diagnosis and reclassified 10 of them as TI-RADS≥4. This procedure could have increased sensitivity up to 98.3%. Although the sensitivity initially found in our study using the TI-RADS scale was relatively low, the value markedly improved when patients with occult microcarcinoma were excluded. Thus, use of the TI-RADS scale would allow for an adequate selection of patients amenable to fine needle aspiration of the nodule. Copyright © 2018 SEEN y SED. Publicado por Elsevier España, S.L.U. All rights reserved.

  1. Identification of Rad23-4 gene required for pollen development in ...

    African Journals Online (AJOL)

    雨林木风

    2012-05-31

    May 31, 2012 ... in ultraviolet (UV)-B–treated rad23-4 mutants. Compared with the wild type ... discovered in yeast (Guzder et al., 1998). Recent studies showed that ... UV-B irradiation can induce accumulations of anthocyanin in the plants.

  2. Breast imaging reporting and data system (BI-RADS) or French 'classification ACR'

    International Nuclear Information System (INIS)

    Dilhuydy, Marie Helene

    2007-01-01

    Summary: The American College of Radiology Task Force on Breast Cancer published in 2003 Fourth edition of BI-RADS for Mammography. It is a lexicon of mammography terms including illustrations of each feature described, followed by a reporting format with assessment categories according to the degree of concern. The aim is to reduce inconsistencies in mammography reports and recommendations for assessment, to facilitate outcome monitoring and to allow each radiologist to audit his own mammography practice. In France, the Societe Francaise de Radiologie acquired the rights to translate BI-RADS, word for word and without adaptation or influence. The last edition was published in 2004. Simultaneously, French Haute Autorite de Sante and National Committee for Breast Cancer Screening proposed to all community practice mammography facilities a classification of detected abnormalities stating more clearly than BI-RADS do which feature has to be included in such and such assessment category and how to manage it. This 'classification ACR' is adapted from BI-RADS but strongly influenced by the context of the French nationwide screening programme, and by European recommendations to limitate undesirable risks of screening such as false positive and overdiagnosis. The differences between the two systems are discussed

  3. Mouse Rad9b is essential for embryonic development and promotes resistance to DNA damage

    Science.gov (United States)

    Leloup, Corinne; Hopkins, Kevin M.; Wang, Xiangyuan; Zhu, Aiping; Wolgemuth, Debra J.; Lieberman, Howard B.

    2010-01-01

    RAD9 participates in promoting resistance to DNA damage, cell cycle checkpoint control, DNA repair, apoptosis, embryogenesis, and regulation of transcription. A paralogue of RAD9 (named RAD9B) has been identified. To define the function of mouse Rad9b (Mrad9b), embryonic stem (ES) cells with a targeted gene deletion were constructed and used to generate Mrad9b mutant mice. Mrad9b−/− embryos are resorbed after E7.5 while some of the heterozygotes die between E12.5 and a few days after birth. Mrad9b is expressed in embryonic brain and Mrad9b+/− embryos exhibit abnormal neural tube closure. Mrad9b−/− mouse embryonic fibroblasts are not viable. Mrad9b−/− ES cells are more sensitive to gamma rays and mitomycin C than Mrad9b+/+ controls, but show normal gamma-ray-induced G2/M checkpoint control. There is no evidence of spontaneous genomic instability in Mrad9b−/− cells. Our findings thus indicate that Mrad9b is essential for embryonic development and mediates resistance to certain DNA damaging agents. PMID:20842695

  4. VirRAD - The virtual radiopharmacy - a virtual learning community in radiopharmacy

    International Nuclear Information System (INIS)

    Mather, S.J.

    2002-01-01

    VirRAD is a new research project funded by the Information Society Technologies programme of the Fifth RTD Framework Programme of the European Union. The aim of VirRAD is to develop an Internet-based virtual learning environment for Radiopharmacy which will facilitate learning and understanding in the speciality at all levels both within and outside the radiopharmaceutical community. The final structure of VirRAD is yet to be decided and will be determined by the needs and desires of its ultimate participants, however it is expected to include multimedia teaching modules for distance learning applications, 3-D simulations of specialised equipment and complex techniques used in radiopharmaceutical preparation and research as well as improved systems of peer-to-peer and student-to-tutor communication and information retrieval. To be as useful and effective as possible VirRAD needs ideas and suggestions from the Nuclear Medicine community. A mechanism for obtaining such input and feedback will be an integral part of the development process

  5. Final disposal of the rad waste materials - question of the nuclear energy implementation and application perspectives

    International Nuclear Information System (INIS)

    Plecas, I.

    1995-01-01

    Two main problems that are denying and slowing down the development of nuclear energy are safe work of the nuclear power facilities (NEF) and disposal of the radioactive waste materials, produced from the NEF and infrastructure facilities of the nuclear fuel cycle (NFC). Although nowadays worldwide knowledge, based on the 45 year of experiences in handling the radioactive waste materials, do not treat the problems of final disposal of the rad waste materials as a task of the primary importance in NFC, this subject still engage experts from this field of investigations, especially in the countries that developed all aspects of the nuclear fuel cycle. Techniques for final disposal of low and intermediate level rad waste materials, are well known and are in state of implementation. The importance of the fundamental safety principles, implemented in the IAEA documents, concerning handling, treatment and final disposal of the rad waste materials, is presented. Future usage of nuclear energy, taking into account all the facts that are dealing with problems of the rad waste materials produced in the NFC, can be a reality. (author.)

  6. An analysis of the distribution and dose response of chromosome aberrations in human lymphocytes after in vitro exposure to 137cesium gamma radiation

    International Nuclear Information System (INIS)

    Doggett, N.A.; McKenzie, W.H.

    1983-01-01

    The chromosome aberration yield for human lymphocytes exposed in vitro to various doses of 137 Cesium has been studied. Dicentric, total acentric, and excess acentric data were seen to follow a Possion distribution. Calculated total hits demonstrated over-dispersion which could possibly be accounted for by a greater occurrence of single-hit phenomena being repaired than two-hit exchange processes. The resulting distribution generally contained an under-representation of cells with odd numbers of hits and an over-representation of zero-and even-hit classes as compared with Poisson predicted values. The relationship between dicentric yield and dose received in rads was fitted to the linear-quadratic formula Y=αD+βD 2 for dicentrics, yielding values of (20.1+-3.8)x10 -4 (aberrations/cell)/rad and (1.89+-0.75)x10 -6 (aberrations/cell)/rad 2 for α and β respectively. A plot of percent ''normal'' cells versus the dose in rads resembled cell survival curves and was fitted to the relation P(D)=100 esup(-Y) where Y=αD+αD 2 with α=(23+-11)x10 -4 rad -1 and β=(8.3+-2.5)x10 -6 rad -2 . A possible use of scoring ''normal'' cells for purposes of biological dosimetry is presented. (orig.)

  7. DMC1 functions in a Saccharomyces cerevisiae meiotic pathway that is largely independent of the RAD51 pathway

    International Nuclear Information System (INIS)

    Dresser, M.E.; Ewing, D.J.; Conrad, M.N.; Dominguez, A.M.; Barstead, R.; Jiang, H.; Kodadek, T.

    1997-01-01

    Meiotic recombination in the yeast Saccharomyces cerevisiae requires two similar recA-like proteins, Dmc1p and Rad51p. A screen for dominant meiotic mutants provided DMC1-G126D, a dominant allele mutated in the conserved ATP-binding site (specifically, the A-loop motif) that confers a null phenotype. A recessive null allele, dmc1-K69E, was isolated as an intragenic suppressor of DMC1-G126D. Dmc1-K69Ep, unlike Dmc1p, does not interact homotypically in a two-hybrid assay, although it does interact with other fusion proteins identified by two-hybrid screen with Dmc1p. Dmc1p, unlike Rad51p, does not interact in the two-hybrid assay with Rad52p or Rad54p. However, Dmc1p does interact with Tid1p, a Rad54p homologue, with Tid4p, a Rad16p homologue, and with other fusion proteins that do not interact with Rad51p, suggesting that Dmc1p and Rad51p function in separate, though possibly overlapping, recombinational repair complexes. Epistasis analysis suggests that DMC1 and RAD51 function in separate pathways responsible for meiotic recombination. Taken together, our results are consistent with a requirement for DMC1 for meiosis-specific entry of DNA double-strand break ends into chromatin. Interestingly, the pattern on CHEF gels of chromosome fragments that result from meiotic DNA double-strand break formation is different in DMC1 mutant strains from that seen in rad50S strains. (author)

  8. The USP1-UAF1 complex interacts with RAD51AP1 to promote homologous recombination repair.

    Science.gov (United States)

    Cukras, Scott; Lee, Euiho; Palumbo, Emily; Benavidez, Pamela; Moldovan, George-Lucian; Kee, Younghoon

    2016-10-01

    USP1 deubiquitinating enzyme and its stoichiometric binding partner UAF1 play an essential role in promoting DNA homologous recombination (HR) repair in response to various types of DNA damaging agents. Deubiquitination of FANCD2 may be attributed to the key role of USP1-UAF1 complex in regulating HR repair, however whether USP1-UAF1 promotes HR repair independently of FANCD2 deubiquitination is not known. Here we show evidence that the USP1-UAF1 complex has a FANCD2-independent function in promoting HR repair. Proteomic search of UAF1-interacting proteins revealed that UAF1 associates with RAD51AP1, a RAD51-interacting protein implicated in HR repair. We show that UAF1 mediates the interaction between USP1 and RAD51AP1, and that depletion of USP1 or UAF1 led to a decreased stability of RAD51AP1. Protein interaction mapping analysis identified some key residues within RAD51AP1 required for interacting with the USP1-UAF1 complex. Cells expressing the UAF1 interaction-deficient mutant of RAD51AP1 show increased chromosomal aberrations in response to Mitomycin C treatment. Moreover, similar to the RAD51AP1 depleted cells, the cells expressing UAF1-interaction deficient RAD51AP1 display persistent RAD51 foci following DNA damage exposure, indicating that these factors regulate a later step during the HR repair. These data altogether suggest that the USP1-UAF1 complex promotes HR repair via multiple mechanisms: through FANCD2 deubiquitination, as well as by interacting with RAD51AP1.

  9. El radón: ¿riesgo para la salud?

    Directory of Open Access Journals (Sweden)

    Juan Miguel Barros Dios

    2011-12-01

    Full Text Available El radón (Rn222 es un gas noble radiactivo que procede directamente del radio (Ra226 cuando este emite una partícula alfa (dos protones y dos neutrones o núcleo de helio, y que a su vez se transforma en otro elemento radiactivo (Po218 al desprenderse de otra partícula alfa. Desde hace varias décadas se conoce su efecto como factor de riesgo del cáncer primario pulmonar, primero en mineros del uranio y posteriormente en la población general expuesta al radón residencial en hogares construidos sobre suelos de rocas ricas en uranio (U238, elemento inicial de la cadena de degradación radiactiva de la que procede el radón. Áreas geológicamente constituidas por granitos o pizarras, como son las de gran parte de Galicia y todo el noroeste y oeste de la península ibérica, han sido catalogadas como de alto riesgo de exhalación de radón al interior de edificios y domicilios. En numerosos países de América y Europa existen desde hace varios lustros, políticas de prevención del cáncer pulmonar en aquellas zonas de riesgo basadas en programas de reducción de radón en los domicilios y edificios públicos. Desde finales de los años 80, la radiación alfa procedente del radón y sus descen- dientes de vida media corta han sido clasificados como agentes cancerígenos por la Internacional Agency of Research on Cancer (Lyon, 1988 y el Nacional Research Council (BEIR IV, 1988, constituyendo la segunda causa de cáncer pulmonar después del tabaco, y responsable del 10 al 15 % de todas las muertes por esa neoplasia. Estudios realizados en Galicia confirman esta evidencia, con riesgos de 2 a 3 en expuestos a concentraciones del gas en domicilios y la responsabilidad directa del 9% de todos los casos de cáncer pulmonar del área estudiada y una interacción radón/tabaco que multiplica por 45 el riesgo.

  10. How and how much does RAD-seq bias genetic diversity estimates?

    Science.gov (United States)

    Cariou, Marie; Duret, Laurent; Charlat, Sylvain

    2016-11-08

    RAD-seq is a powerful tool, increasingly used in population genomics. However, earlier studies have raised red flags regarding possible biases associated with this technique. In particular, polymorphism on restriction sites results in preferential sampling of closely related haplotypes, so that RAD data tends to underestimate genetic diversity. Here we (1) clarify the theoretical basis of this bias, highlighting the potential confounding effects of population structure and selection, (2) confront predictions to real data from in silico digestion of full genomes and (3) provide a proof of concept toward an ABC-based correction of the RAD-seq bias. Under a neutral and panmictic model, we confirm the previously established relationship between the true polymorphism and its RAD-based estimation, showing a more pronounced bias when polymorphism is high. Using more elaborate models, we show that selection, resulting in heterogeneous levels of polymorphism along the genome, exacerbates the bias and leads to a more pronounced underestimation. On the contrary, spatial genetic structure tends to reduce the bias. We confront the neutral and panmictic model to "ideal" empirical data (in silico RAD-sequencing) using full genomes from natural populations of the fruit fly Drosophila melanogaster and the fungus Shizophyllum commune, harbouring respectively moderate and high genetic diversity. In D. melanogaster, predictions fit the model, but the small difference between the true and RAD polymorphism makes this comparison insensitive to deviations from the model. In the highly polymorphic fungus, the model captures a large part of the bias but makes inaccurate predictions. Accordingly, ABC corrections based on this model improve the estimations, albeit with some imprecisions. The RAD-seq underestimation of genetic diversity associated with polymorphism in restriction sites becomes more pronounced when polymorphism is high. In practice, this means that in many systems where

  11. Division delay after low x-ray doses and treatment with cyclohexionide

    International Nuclear Information System (INIS)

    Schneiderman, M.H.; Braby, L.A.; Roesch, W.C.

    1977-01-01

    Radiation-induced division delay of Chinese hamster ovary cells located in G 2 , and in G 2 between the cycloheximide and x-ray transition points, was measured by the mitotic cell selection technique. The mitotic yield (number of mitotic cells after treatment expressed as a fraction of the control) decreased with increasing radiation dose (4.5 to 34 rad). However, either because some cells were not delayed or because delayed cells recovered rapidly, the mitotic yield did not fall to zero. When cycloheximide was combined with radiation to prevent repair of the radiation damage, only cells which were past the cycloheximide transition point and not delayed by the radiation were selected. The location of the transition points determined from the combined drug plus low-dose radiation (4.5 to 34 rad) experiments indicate a dose-dependent relationship, with more cells delayed as the dose was increased. In addition, the transition point for cells treated with cycloheximide plus 150 rad of x rays was closer to division than the 150 rad of x rays alone. These results are discussed in light of a recent model for radiation-induced division delay proposed by Dewey and Highfield

  12. Development of tumours in dogs exposed to low doses of gamma radiation for a long time

    International Nuclear Information System (INIS)

    Yakovleva, V.I.

    1974-01-01

    150 animals were exposed to chronic (doses 21, 63 and 125 rad/year, with dose rates of 0.06, 0.17 and 0.34 rad/day, respectively) or combined γ-irradiation (chronic irradiation at 63 rad/year and acute irradiation at 58 and 126 rad/year) for a total period of 6 years. Post-mortem examination of 74 irradiated a7 animals revealed malignant neoplasms in 5 (flat-cell pulmonary carcinoma, hepatocellular liver carcinoma, skin basalioma, osteogenic costal sarcoma, and eye melanoma) and bening neoplasms also in 5 (3 leidigomas, parenchymatous thyroid struma and angiofibroma of hypodermic tissue). Of the 19 dogs in the control group, 2 had mammary tumours (cystadenoma and adenofibroma that changed to adenocarcinoma). Most of the neoplasms were seen in animals exposed to chronic irradiation with the highest dose rates as well as in those which received the highest total doses used in chronic irradiation. Acute effects were noted twice as often as chronic ones

  13. Effects of low X-ray doses in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Jordan, A.; Laskowski, W.

    1987-01-01

    Three strains of Saccharomyces cerevisiae with different capacities for repair of radiation damage (RAD, rad18, and rad52) have been tested for their colony forming ability (CFA) and growth rates after application of small X-ray doses from 3.8 mGy to 40 Gy. There was no reproducible increase in CFA observable after application of doses between 3.8 mGy and 4.7 Gy.X-ray doses of 40 Gy causing an inactivation of CFA from 90% to 50%, depending on the repair capacity of the strains used, caused a reduced increase in optical density during 2 h buffer treatment in comparison to unirradiated cells. This reduction however, is reversible as soon as the cells are transferred into nutrient medium. One hour after transfer into growh medium the portions of cells with large buds (Gs and M phase) and cells with small buds (S phase) are drastically different in irradiated cells from those obtained in unirradiated cells. The time necessary for separation of mother and daughter cells is prolonged by X-ray irradiation and the formation of new buds is retarded. (orig.)

  14. Self-dose and fading of CaSO4(Dy/Tm) and CaF2 (natural) TL phosphors in environmental radiation monitoring

    International Nuclear Information System (INIS)

    Nambi, K.S.V.

    1982-01-01

    A 'shielded storage experiment' for estimating both the 'self-dose' and 'fading' of TL phosphors under conditions akin to those faced in environmental monitoring applications is described. Using this method, self-dose rates of 0.32 +- 0.10(sigma) μ rad h -1 and 1.16 +- 0.02(sigma) μ rad h -1 have been obtained for CaF 2 (natural) and CaSO 4 (Dy) phosphors; the thermal decay constants at 25 0 C for these phosphors turn out to be 27 X 10 -6 h -6 ad 12 X 10 -6 h -1 , respectively. Estimation of the self-doses from radioactivity measurements of the phosphors concerned is also presented and the differences explained. A very high self-dose rate of 5.6 μ rad h -1 was estimated by the latter method for a sample of CaSO 4 (Tm) phosphor. (orig.)

  15. Simple rules for ultrasonographic subcategorization of BI-RADS{sup ®}-US 4 breast masses

    Energy Technology Data Exchange (ETDEWEB)

    Jales, Rodrigo Menezes, E-mail: rodrigoj@hotmail.com [Department of Obstetrics and Gynecology, Faculty of Medical Sciences, State University of Campinas – Unicamp, Campinas, São Paulo (Brazil); Sarian, Luís Otavio, E-mail: luis.sarian@gmail.com [Department of Obstetrics and Gynecology, Faculty of Medical Sciences, State University of Campinas – Unicamp, Campinas, São Paulo (Brazil); Torresan, Renato, E-mail: torresan@terra.com.br [Department of Obstetrics and Gynecology, Faculty of Medical Sciences, State University of Campinas – Unicamp, Campinas, São Paulo (Brazil); Marussi, Emílio Francisco, E-mail: efmarussi@uol.com.br [Department of Obstetrics and Gynecology, Faculty of Medical Sciences, State University of Campinas – Unicamp, Campinas, São Paulo (Brazil); Álvares, Beatriz Regina, E-mail: alvaresb@terra.com.br [Department of Radiology, Faculty of Medical Sciences, State University of Campinas – Unicamp, Campinas, São Paulo (Brazil); Derchain, Sophie, E-mail: derchain@fcm.unicamp.br [Department of Obstetrics and Gynecology, Faculty of Medical Sciences, State University of Campinas – Unicamp, Campinas, São Paulo (Brazil)

    2013-08-15

    Objectives: To evaluate an objective method for ultrasonographic (US) subcategorization of BI-RADS{sup ®}-US 4 breast masses based on clear and simple rules in order for woman to benefit from a more complete and homogeneous breast mass analysis. Methods: In this cross-sectional study, we selected 330 women, with 339 US breast masses, classified as BI-RADS{sup ®}-US 4. Three physicians experienced in breast imaging independently reviewed all US images, assessing mass shape, margins, orientation, echo texture and vascularity. These experts further subdivided the masses into subcategories 4a, 4b and 4c, according to simple US rules. Inter-observer agreement was calculated for US features categories and for final subcategory assessment. We also estimated the positive predictive value (PPV) for BI-RADS{sup ®}-US subcategories 4a, 4b and 4c assigned by each of the three observers. Results: Pathological examination of all masses confirmed 144 (42%) malignant and 195 (58%) benign tumors. Moderate agreement was obtained for mass shape, margins, vascularity and for final BI-RADS{sup ®}-US 4 subcategory. Substantial agreement was obtained for the description of mass orientation and echo texture. The PPV for subcategories 4a, 4b and 4c were, 17%, 45% and 85%, respectively, for the first observer and 20%, 38% and 79% and 17%, 40% and 85% for the other two observers. Conclusion: Standardization of a US subcategorization of BI-RADS{sup ®}-US 4 breast masses seems to be feasible, with substantial inter-observer agreement and progressive increase in the PPV in the subcategories 4a, 4b and 4c, provided that clear and simple classification rules are defined.

  16. 222Rn Determination In Drinking Waters - RAD7 And LSC Technique Comparison

    International Nuclear Information System (INIS)

    Todorovic, N.; Stojkovic, I.; Nikolov, J.; Tenjovic, B.

    2015-01-01

    A procedure for the determination of 222Rn in environmental water samples using liquid scintillation counting (LSC) was applied and optimized. For radon determination in drinking water from groundwater and surface water sources by LSC, the EPA Method 913.0 was used. A minimum detectable activity of 0.029 Bq L-1 in a 20 mL glass vial (10 mL water sample mixed with 10 mL of liquid scintillation cocktail) has been achieved during 300 minutes of measurement time. The procedure was compared with RAD7 radon detector measurements. Factors that affect the measurement accuracy and precision of RAD7 radon detector are the sampling technique, sample concentration, sample size, counting time, temperature, relative humidity and background effects. The minimal detectable activity (MDA) for RAD7 technique was found to be 0.1 Bq/L. From obtained results of 222Rn measurements in 15 water samples with different 222Rn activities, correlation between the two techniques applied for measurements of 222Rn in water samples (A less than 400 Bq/L) was determined. There is reasonable agreement (within statistical uncertainties) between the various techniques in most cases, while disagreements most likely come from systematic uncertainties associated with sampling procedures. Discrepancy in determined activities between the two techniques becomes more evident with increased 222Rn activities in water. LSC technique gives in general higher activity concentrations for about 30 percent than RAD7 spectrometer. The interpretation of shown results could be that RAD7 is not properly calibrated for higher activities, since USA reference level of 222Rn concentrations in water is only 11.1 Bq/L (US EPA, Proposed Radon in Drinking Water Regulation). (author).

  17. Medullary thyroid carcinoma: Application of Thyroid Imaging Reporting and Data System (TI-RADS) Classification.

    Science.gov (United States)

    Yun, Gabin; Kim, Yeo Koon; Choi, Sang Il; Kim, Ji-Hoon

    2018-04-21

    To evaluate the applicability of ultrasound (US)-based Thyroid Imaging Reporting and Data System (TI-RADS) for evaluating medullary thyroid carcinoma (MTC). US images and medical records of patients with cytopathology-confirmed MTC between June 2003 and November 2016 were retrospectively reviewed. Four independent reviewers (two experienced and two inexperienced radiologists) evaluated 57 pre-operative US images of patients with MTC for shape, composition, echogenicity, margin, calcification of the MTC nodules, and categorized the nodules using TI-RADS classification. Weighted Kappa statistics was used to determine the inter-observer agreement of TI-RADS. Univariate and multivariate analyses were performed to assess US findings associated with lymph node metastasis. Ninety-five percent of nodules were classified as either high suspicion (68%) or intermediate suspicion (26%). The overall inter-rater agreement was good (Kappa 0.84, agreement 91.52%), and inexperienced reviewers also showed good agreements with the most experienced reviewer (weighted Kappa 0.73 and 0.81). According to the univariate analysis, TI-RADS category 5, shape, microcalcification, and extrathyroid extension were significantly associated with lymph node metastasis in MTC patients (p = 0.003, 0.008, 0.001, and 0.021, respectively). As per the multivariate analysis, the presence of microcalcification and the irregular shape of the nodule were significantly associated with metastatic lymph nodes in MTC patients (odds ratio, 26.6; 95% CI, 2.7-263.7, p = 0.005, odds ratio, 14.7; 95% CI, 1.3-170, p = 0.031, respectively). TI-RADS is applicable for the evaluation of MTC nodules with good inter-observer agreement.

  18. Indexing thoracic CT reports using a preliminary version of a standardized radiological lexicon (RadLex).

    Science.gov (United States)

    Marwede, Dirk; Schulz, Thomas; Kahn, Thomas

    2008-12-01

    To validate a preliminary version of a radiological lexicon (RadLex) against terms found in thoracic CT reports and to index report content in RadLex term categories. Terms from a random sample of 200 thoracic CT reports were extracted using a text processor and matched against RadLex. Report content was manually indexed by two radiologists in consensus in term categories of Anatomic Location, Finding, Modifier, Relationship, Image Quality, and Uncertainty. Descriptive statistics were used and differences between age groups and report types were tested for significance using Kruskal-Wallis and Mann-Whitney Test (significance level <0.05). From 363 terms extracted, 304 (84%) were found and 59 (16%) were not found in RadLex. Report indexing showed a mean of 16.2 encoded items per report and 3.2 Finding per report. Term categories most frequently encoded were Modifier (1,030 of 3,244, 31.8%), Anatomic Location (813, 25.1%), Relationship (702, 21.6%) and Finding (638, 19.7%). Frequency of indexed items per report was higher in older age groups, but no significant difference was found between first study and follow up study reports. Frequency of distinct findings per report increased with patient age (p < 0.05). RadLex already covers most terms present in thoracic CT reports based on a small sample analysis from one institution. Applications for report encoding need to be developed to validate the lexicon against a larger sample of reports and address the issue of automatic relationship encoding.

  19. Using RAD-seq to recognize sex-specific markers and sex chromosome systems.

    Science.gov (United States)

    Gamble, Tony

    2016-05-01

    Next-generation sequencing methods have initiated a revolution in molecular ecology and evolution (Tautz et al. ). Among the most impressive of these sequencing innovations is restriction site-associated DNA sequencing or RAD-seq (Baird et al. ; Andrews et al. ). RAD-seq uses the Illumina sequencing platform to sequence fragments of DNA cut by a specific restriction enzyme and can generate tens of thousands of molecular genetic markers for analysis. One of the many uses of RAD-seq data has been to identify sex-specific genetic markers, markers found in one sex but not the other (Baxter et al. ; Gamble & Zarkower ). Sex-specific markers are a powerful tool for biologists. At their most basic, they can be used to identify the sex of an individual via PCR. This is useful in cases where a species lacks obvious sexual dimorphism at some or all life history stages. For example, such tests have been important for studying sex differences in life history (Sheldon ; Mossman & Waser ), the management and breeding of endangered species (Taberlet et al. ; Griffiths & Tiwari ; Robertson et al. ) and sexing embryonic material (Hacker et al. ; Smith et al. ). Furthermore, sex-specific markers allow recognition of the sex chromosome system in cases where standard cytogenetic methods fail (Charlesworth & Mank ; Gamble & Zarkower ). Thus, species with male-specific markers have male heterogamety (XY) while species with female-specific markers have female heterogamety (ZW). In this issue, Fowler & Buonaccorsi () illustrate the ease by which RAD-seq data can generate sex-specific genetic markers in rockfish (Sebastes). Moreover, by examining RAD-seq data from two closely related rockfish species, Sebastes chrysomelas and Sebastes carnatus (Fig. ), Fowler & Buonaccorsi () uncover shared sex-specific markers and a conserved sex chromosome system. © 2016 John Wiley & Sons Ltd.

  20. Interobserver variability of ultrasound elastography and the ultrasound BI-RADS lexicon of breast lesions.

    Science.gov (United States)

    Park, Chang Suk; Kim, Sung Hun; Jung, Na Young; Choi, Jae Jung; Kang, Bong Joo; Jung, Hyun Seouk

    2015-03-01

    Elastographpy is a newly developed noninvasive imaging technique that uses ultrasound (US) to evaluate tissue stiffness. The interpretation of the same elastographic images may be variable according to reviewers. Because breast lesions are usually reported according to American College of Radiology Breast Imaging and Data System (ACR BI-RADS) lexicons and final category, we tried to compare observer variability between lexicons and final categorization of US BI-RADS and the elasticity score of US elastography. From April 2009 to February 2010, 1356 breast lesions in 1330 patients underwent ultrasound-guided core biopsy. Among them, 63 breast lesions in 55 patients (mean age, 45.7 years; range, 21-79 years) underwent both conventional ultrasound and elastography and were included in this study. Two radiologists independently performed conventional ultrasound and elastography, and another three observers reviewed conventional ultrasound images and elastography videos. Observers independently recorded the elasticity score for a 5-point scoring system proposed by Itoh et al., BI-RADS lexicons and final category using ultrasound BI-RADS. The histopathologic results were obtained and used as the reference standard. Interobserver variability was evaluated. Of the 63 lesions, 42 (66.7 %) were benign, and 21 (33.3 %) were malignant. The highest value of concordance among all variables was achieved for the elasticity score (k = 0.59), followed by shape (k = 0.54), final category (k = 0.48), posterior acoustic features (k = 0.44), echogenecity and orientation (k = 0.43). The least concordances were margin (k = 0.26), lesion boundary (k = 0.29) and calcification (k = 0.3). Elasticity score showed a higher level of interobserver agreement for the diagnosis of breast lesions than BI-RADS lexicons and final category.

  1. Bone-and-muscle-equivalent solid chemical dose meters for photon and electron doses above one kilorad

    International Nuclear Information System (INIS)

    McLaughlin, W.L.; Rosenstein, M.; Levine, H.

    1975-01-01

    Conventional solid dose meters, such as plastic films, powders, emulsions, glasses, ceramics and gels, have a response to ionizing photons and electrons that varies markedly over a broad spectrum when compared with the absorption characteristics of biological tissues. New radiochromic dyed plastic dose meters have been developed with X- and gamma ray and electron energy absorption cross-sections (calculated) and radiation energy responses (experimental) corresponding approximately to those for human muscle and bone, for a spectrum from a few keV to at least 10 MeV. Three-dimensional solid dose meters useful over the absorbed dose range of 10 3 to 10 6 rad are formed by thermosetting a selected combination of monomers containing the radiochromic dye in solution. Thin-film dose meters for the dose range 10 5 to 10 7 rad are formed by casting on optically flat surfaces strippable layers of special combinations of polymers and dyes in solution. The response of these systems to X- and gamma rays and electrons has been studied over various radiation spectra, dose-rates and temperatures during irradiation. (author)

  2. Cloning of an E. coli RecA and yeast RAD51 homolog, radA, an allele of the uvsC in Aspergillus nidulans and its mutator effects.

    Science.gov (United States)

    Seong, K Y; Chae, S K; Kang, H S

    1997-04-30

    An E. coli RecA and yeast RAD51 homolog from Aspergillus nidulans, radA, has been cloned by screening genomic and cDNA libraries with a PCR-amplified probe. This probe was generated using primers carrying the conserved sequences of eukaryotic RecA homologs. The deduced amino acid sequence revealed two conserved Walker-A and -B type nucleotide-binding domains and exhibited 88%, 60%, and 53% identity with Mei-3 of Neurospora crassa, rhp51+ of Schizosaccharomyces pombe, and Rad51 of Saccharomyces cerevisiae, respectively. radA null mutants constructed by replacing the whole coding region with a selection marker showed high methyl methanesulfonate (MMS) sensitivity. Heterozygous diploids of radA disruptant with the uvsC114 mutant failed to complement with respect to MMS-sensitivity, indicating that radA is an allele of uvsC. In selecting spontaneous forward selenate resistant mutations, mutator effects were observed in radA null mutants similarly to those shown in uvsC114 mutant strains.

  3. Usefulness of combined use of contrast-enhanced ultrasound and TI-RADS classification for the differentiation of benign from malignant lesions of thyroid nodules.

    Science.gov (United States)

    Zhang, Yan; Zhou, Ping; Tian, Shuang-Ming; Zhao, Yong-Feng; Li, Jia-Le; Li, Lan

    2017-04-01

    To study the thyroid image reporting and data system (TI-RADS) classification and the contrast-enhanced ultrasound (CEUS) enhancement pattern of thyroid nodules, and to determine whether combined use of both methods is helpful in the diagnosis of thyroid nodules. A total of 319 thyroid nodules in 246 patients were assessed with TI-RADS, CEUS and a combination of both methods. The diagnostic performance of TI-RADS, CEUS and a combination of both methods was compared. The accuracy in the diagnosis of thyroid nodules was 90.3 % for TI-RADS, 90.0 % for CEUS and 96.0 % for a combination of both methods respectively. A statistically significant difference was not observed in the diagnostic accuracy of CEUS and TI-RADS (P > 0.05). However, a significant difference was observed between a combination of both methods and either alone (P TI-RADS classifications of 4a and 4b thyroid nodules compared with TI-RADS alone (P  0.05). The improved TI-RADS, when combined with CEUS, could significantly improve the diagnostic accuracy for thyroid nodules, especially for TI-RADS class-4 thyroid nodules. • TI-RADS can be used as the primary diagnostic standard for thyroid nodules • CEUS can be used as an important complement to TI-RADS • The improved TI-RADS can significantly improve the qualitative diagnostic accuracy.

  4. Early Postoperative Low Expression of RAD50 in Rectal Cancer Patients Associates with Disease-Free Survival

    Directory of Open Access Journals (Sweden)

    Vincent Ho

    2017-11-01

    Full Text Available Background: Molecular biomarkers have the potential to predict response to the treatment of rectal cancer. In this study, we aimed to evaluate the prognostic and clinicopathological implication of RAD50 (DNA repair protein RAD50 homolog expression in rectal cancer. Methods: A total of 266 rectal cancer patients who underwent surgery and received chemo- and radiotherapy between 2000 and 2011 were involved in the study. Postoperative RAD50 expression was determined by immunohistochemistry in surgical samples (n = 266. Results: Using Kaplan–Meier survival analysis, we found that low RAD50 expression in postoperative samples was associated with worse disease free survival (p = 0.001 and overall survival (p < 0.001 in early stage/low-grade tumors. In a comparison of patients with low vs. high RAD50 expression, we found that low levels of postoperative RAD50 expression in rectal cancer tissues were significantly associated with perineural invasion (p = 0.002. Conclusion: Expression of RAD50 in rectal cancer may serve as a prognostic biomarker for long-term survival of patients with perineural invasion-positive tumors and for potential use in early stage and low-grade rectal cancer assessment.

  5. Some effects of random dose measurement errors on analysis of atomic bomb survivor data

    International Nuclear Information System (INIS)

    Gilbert, E.S.

    1985-01-01

    The effects of random dose measurement errors on analyses of atomic bomb survivor data are described and quantified for several procedures. It is found that the ways in which measurement error is most likely to mislead are through downward bias in the estimated regression coefficients and through distortion of the shape of the dose-response curve. The magnitude of the bias with simple linear regression is evaluated for several dose treatments including the use of grouped and ungrouped data, analyses with and without truncation at 600 rad, and analyses which exclude doses exceeding 200 rad. Limited calculations have also been made for maximum likelihood estimation based on Poisson regression. 16 refs., 6 tabs

  6. A wide range survey meter for estimating γ- and β-dose rates

    International Nuclear Information System (INIS)

    Jones, A.R.

    1980-09-01

    A survey meter has been developed to measure β-dose rates in the range 0.1 - 100 rad/h (1 mGy/h - 1 Gy/h) and γ-dose rates in the range 1 mrad/h - 100 rad/h (10 μGy/h-1 Gy/h). It also provides an audible warning of high γ-dose rates and an audible and visible warning when a predetermined γ-dose is exceeded. The report describes the design of the survey meter and presents data measured on the performance of an engineering prototype. Factors which affect performance and have been investigated are temperature, battery voltage (and type of battery), GM counter counting loss, direction of incident radiation, and energy of γ-rays. Finally, the application and calibration of the survey meter are discussed. (auth)

  7. Design and dosimetry of an eye plaque containing I-125 seeds: An improved dose distribution

    International Nuclear Information System (INIS)

    Detorie, N.A.; Tkacik, M.F.; Neglia, W.J.; Jenkins, D.; Shadday, J.

    1986-01-01

    To treat intraocular tumors, a temporarily implanted eye plaque, containing 24 I-125 seeds (3M model 6711), was fabricated from 0.6-mm-thick lead disk with a 1.5-cm diameter. The I-125 seeds were distributed in a particular geometric pattern to average the dose anisotropy of each individual seed. Water phantom measurements made with TLD chips (LiF) and film over the approximate depth range of 1-25 mm were compared with treatment planning computer calculations (Capintec RT-108). Data indicate that the specified geometry produces a dose distribution delivering a tumor dose of 10,000 rad to the tumor apex (7 mm) without exceeding a sclera dose (1 mm) of 40,000 rad. Information regarding fabrication, dosimetry, and radiation safety is presented

  8. The management of spent resins at rad waste installation (RWI)

    International Nuclear Information System (INIS)

    Johan, Bahdir

    2002-01-01

    During years 2000 RWI has been managed 1.596 liters the spent resins from MPR, multipurpose reactor G.A. Siwabessy (RSG-GAS). The spent resins containing 6 0 C o, 1 37 C s and 8 9 S r. The immobilization of spent resins using Portland cement type I and sand in shell 950 liter has been carried out. The immobilization product quality was characterized by measurement of surface exposure, density, compression strength and leaching rate. The samples each being 3000 g are made by taking cement slurry from the 950 liter shell. The samples are molded in the form of cylinder of 50 mm diameter and height 50 mm. The density was determined by weighing and measuring sample's volume. The compression strength was determinate using P aul Weber a pparatus. The leaching rate by immerse of the samples in the demineralized water and the rate the contact surface dose measures using survey meter. The results show that the density ρ= (1,72 ± 0,01) s/d 1,73 ± 0,03) g.cm - 3 , the compression strength Γ= (20,10 ± 0,02 s/d 20,18 ± 0,02) N.mm - 2 , the leaching rate R n = (1,32x10 - 2 s /d 2,0x10 - 3 ) g.cm - 2 . h - 1 , the contact surface rate D 0 = (0,374 s/d 0,79) mrem.jam - 1 a nd 1m distance from the surface D 1 = (0,18 s/d 0,19) mrem.jam - 1 h ave been in compliance with the criteria recommended by IAEA the quality of spent resins concrete in shell 950 liters (number 22C to 27C) is qualified for ultimate disposal

  9. RAD50 germline mutations are associated with poor survival in BRCA1/2-negative breast cancer patients.

    Science.gov (United States)

    Fan, Cong; Zhang, Juan; Ouyang, Tao; Li, Jinfeng; Wang, Tianfeng; Fan, Zhaoqing; Fan, Tie; Lin, Benyao; Xie, Yuntao

    2018-05-04

    RAD50 is a highly conserved DNA double-strand break (DSB) repair gene. However, the associations between RAD50 germline mutations and the survival and risk of breast cancer have not been fully elucidated. Here, we aimed to investigate the clinical impact of RAD50 germline mutations in a large cohort of unselected breast cancer patients. In this study, RAD50 germline mutations were determined using next-generation sequencing in 7657 consecutive unselected breast cancer patients without BRCA1/2 mutations. We also screened for RAD50 recurrent mutations (L719fs, K994fs, and H1269fs) in 5000 healthy controls using Sanger sequencing. We found that 26 out of 7657 (0.34%) patients had RAD50 pathogenic mutations, and 16 patients carried one of the three recurrent mutations (L719fs, n=6 cases; K994fs, n=5 cases; and H1269fs, n=5 cases); the recurrent mutation rate was 0.21%. The frequency of the three recurrent mutations in the 5000 healthy controls was 0.18% (9/5000). These mutations did not confer an increased risk of breast cancer in the studied patients [odds ratios (OR), 1.16; 95% confidence interval (CI), 0.51-2.63; P = 0.72]. Nevertheless, multivariate analysis revealed that RAD50 pathogenic mutations were an independent unfavourable predictor of recurrence-free survival (RFS) [adjusted hazard ratio (HR) 2.66; 95% CI, 1.18-5.98; P=0.018] and disease-specific survival (DSS) (adjusted HR 4.36; 95% CI, 1.58-12.03; P=0.004) in the entire study cohort. Our study suggested that RAD50 germline mutations are not associated with an increased risk of breast cancer, but patients with RAD50 germline mutations have unfavourable survival compared with patients without these mutations. This article is protected by copyright. All rights reserved. © 2018 UICC.

  10. Radón y sus efectos en la salud en trabajadores de minas de uranio

    Directory of Open Access Journals (Sweden)

    Gonzalo Aicardi-Carrillo

    2015-03-01

    Full Text Available Introducción: El radón es un gas presente en subsuelo, especialmente en minas de uranio, que produce consecuencias sobre la salud, entre las que destaca el cáncer de pulmón. En EEUU es la segunda causa de mortalidad por esta enfermedad. Pese a la fuerte relación causal no existe normativa específica europea de regulación en mineros. Objetivos: Identificar el efecto del radón y sus derivados sobre la salud de los trabajadores de minas de uranio; describir la asociación entre exposición a radón y a otros minerales sobre la salud y asociación entre radón y consumo de tabaco. Metodología: Realizamos una revisión bibliográfica de literatura publicada entre 2007 y 2014, en bases de datos biomédicas, utilizando los criterios de inclusión y exclusión previamente establecidos. Resultados: Se revisan 32 artículos, encontrando un aumento significativo de cáncer pulmonar (SMR-2.03, IC95% 1.96-2.10, incluso a dosis bajas (300-WLM así como otros cánceres (laringe, gástrico, hepático y leucemia y enfermedades cerebrovasculares, controlando posibles factores de confusión (tabaco, silicosis, cuarzo y arsénico no encontrando relación significativa ni sinergias. Conclusión: Existe asociación entre la exposición al radón y cáncer pulmonar en minas de uranio, con un periodo medio de latencia de 20 años, determinado por la dosis de radón y el tiempo de exposición. No se ha demostrado riesgo de desarrollar otros tipos de tumores, y los estudios que lo sugieren son poco consistentes.

  11. Beta and gamma dose calculations for PWR and BWR containments

    International Nuclear Information System (INIS)

    King, D.B.

    1989-07-01

    Analyses of gamma and beta dose in selected regions in PWR and BWR containment buildings have been performed for a range of fission product releases from selected severe accidents. The objective of this study was to determine the radiation dose that safety-related equipment could experience during the selected severe accident sequences. The resulting dose calculations demonstrate the extent to which design basis accident qualified equipment could also be qualified for the severe accident environments. Surry was chosen as the representative PWR plant while Peach Bottom was selected to represent BWRs. Battelle Columbus Laboratory performed the source term release analyses. The AB epsilon scenario (an intermediate to large LOCA with failure to recover onsite or offsite electrical power) was selected as the base case Surry accident, and the AE scenario (a large break LOCA with one initiating event and a combination of failures in two emergency cooling systems) was selected as the base case Peach Bottom accident. Radionuclide release was bounded for both scenarios by including spray operation and arrested sequences as variations of the base scenarios. Sandia National Laboratories used the source terms to calculate dose to selected containment regions. Scenarios with sprays operational resulted in a total dose comparable to that (2.20 x 10 8 rads) used in current equipment qualification testing. The base case scenarios resulted in some calculated doses roughly an order of magnitude above the current 2.20 x 10 8 rad equipment qualification test region. 8 refs., 23 figs., 12 tabs

  12. Dose-rate effects in synchronous mammalian cells in culture. II. A comparison of the life cycle of HeLa cells during continuous irradiation or multiple-dose fractionation

    International Nuclear Information System (INIS)

    Mitchell, J.B.; Bedford, J.S.

    1977-01-01

    The life cycle of synchronized S3 HeLa cells was examined during continuous irradiation at a dose rate of approximately 37 rad/hr and during multiple dose fractionation schedules of the same average dose rate (total dose / overall time = average dose rate). For all regimes given at this dose rate the effects on the life cyclee were similar. Cells progressed through G1 and S without appreciable delay and experienced a minimum G2 delay of about 10 hr. Cells eventually entered mitosis but virtually none were able to complete a successful division

  13. Evidence that a recombinationless strain, rad 51, of Saccharomyces cerevisiae lacks the budding cell resistance to γ-rays

    International Nuclear Information System (INIS)

    Hama-Inaba, Hiroko; Saeki, Tetsuya

    1975-01-01

    The radiosensitivities of a wild-type and x-ray sensitive mutant, rad 51 (defective in genetic recombination) of Saccharomyces cerevisiae to γ-rays were compared, using non-synchronized and partially synchronized cultures. The rad 51 cells, either haploid or diploid, showed only very small changes in radiosensitivity during cell growth, whereas the wild-type cells, especially haploid, showed the well-known budding resistance. The heterozygous (wild/rad 51) diploid cells showed in a survival curve a remarkable budding resistance and sigmoidal inactivation kinetics similar to those of wild-type homozygous diploid cells. (author)

  14. Radiation absorbed-dose estimates for the liver, spleen, and metaphyseal growth complexes in children undergoing gallium-67 citrate scanning

    International Nuclear Information System (INIS)

    Thomas, S.R.; Gelfand, M.J.; Burns, G.S.; Purdom, R.C.; Kereiakes, J.G.; Maxon, H.R.

    1983-01-01

    Quantitative conjugate-view external counting techniques were applied to estimate the radiation dose to the liver, spleen, and metaphyseal growth complexes (distal femur and proximal tibia) for ten pediatric patients undergoing gallium-67 scanning procedures. The effective half-life of Ga 67 in these organs was approximately 78 hours. The dose per unit of administered activity for the liver and spleen was between 0.3 and 4.0 rad/mCi (0.08 to 1.08 Gy/GBq) and 0.5 and 7.0 rad/mCi (0.13 to 1.89 Gy/GBq), respectively. For the metaphyseal growth plates, the range was 2.3 to 14.3 rad/mCi (0.62 to 3.86 Gy/GBq)

  15. The PCNA interaction protein box sequence in Rad54 is an integral part of its ATPase domain and is required for efficient DNA repair and recombination

    DEFF Research Database (Denmark)

    Burgess, Rebecca C; Sebesta, Marek; Sisakova, Alexandra

    2013-01-01

    Rad54 is an ATP-driven translocase involved in the genome maintenance pathway of homologous recombination (HR). Although its activity has been implicated in several steps of HR, its exact role(s) at each step are still not fully understood. We have identified a new interaction between Rad54...... and the replicative DNA clamp, proliferating cell nuclear antigen (PCNA). This interaction was only mildly weakened by the mutation of two key hydrophobic residues in the highly-conserved PCNA interaction motif (PIP-box) of Rad54 (Rad54-AA). Intriguingly, the rad54-AA mutant cells displayed sensitivity to DNA damage...

  16. Dose limits

    International Nuclear Information System (INIS)

    Fitoussi, L.

    1987-12-01

    The dose limit is defined to be the level of harmfulness which must not be exceeded, so that an activity can be exercised in a regular manner without running a risk unacceptable to man and the society. The paper examines the effects of radiation categorised into stochastic and non-stochastic. Dose limits for workers and the public are discussed

  17. Dose-rate effects in plateau-phase cultures of S3 HeLa and V79 cells

    International Nuclear Information System (INIS)

    Mitchell, J.B.; Bedford, J.S.; Bailey, S.M.

    1979-01-01

    Dose-rate effects on cell survival were studied for log-, fed plateau-, and unfed plateau-phase cultures of V79 and S3 HeLa cells. For log-phase cultures, repair, cell-cycle redistribution, and cell division during exposure can contribute to the overall dose-rate effect, but their relative contributions are difficult to determine. With plateau-phase cultures, the cell-cycle times are greatly lengthened, for those cells that are in cycle. Hence, the contribution to the overall dose-rate effect of cell-cycle redistribution and cell division during the exposure could be minimized using plateau-phase cultures. With respect to the acute dose-survival curves, there was a clear loss in effectiveness when the dose rate was lowered to 154 rad/hr for both fed and unfed plateau-phase HeLa and V79 cells. There was no further reduction in effectiveness per unit dose, however, when the dose rate was reduced to 55 rad/hr. Since there was virtually no cell division or cell-cycle redistribution, it may be that a limit to the repair-dependent dose-rate effect at 37 0 C has been reached at a dose rate of 154 rad/hr

  18. Effect of low dose x-irradiation on alloantigen sensitized and unsensitized lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Dohi, Kiyohiko; Yahata, Hiroshi; Fukuda, Yasuhiko; Asahara, Toshimasa; Ono, Eiji; Ezaki, Haruo

    1984-12-01

    The effect of local graft irradiation on immune response in allograft in which acute rejection occurs was studied using an in vitro model. Unidirectional mixed lymphocyte culture (MLC) was used as the in vitro model of acute rejection. 150 and 300 rad x-irradiation suppressed mixed lymphocyte reaction (MLR) but did not cell-mediated-lympholysis (CML) of unsensitized lymphocytes. X-irradiated alloantigen sensitized cells (ASC) generated in 6-day MLC suppressed MLR and CML of unsensitized lymphocytes. Suppressive effects of x-irradiated ASC were of the same degree by x-irradiation doses of 150-500 rad. Suppressive effect of x-irradiation was maintained for only a short period after x-irradiation. Potential function of suppressor precursor cells among unsensitized lymphocytes was abolished by x-irradiation of 300 rad. (author).

  19. Analysis of dose, dose-rate and treatment time in the production of injuries by radium treatment for cancer of the uterine cervix; and reply by K.H. Lee

    International Nuclear Information System (INIS)

    Saunders, J.E.

    1977-01-01

    The author of the first letter has detected several errors and inconsistencies in the treatment of the data in a recent paper (Lee, K.H., Kagan, A.R., Nussbaum, H., Wollin, M., Winkley, J.H., and Norman, A., 1976, Br. J. Radiol., vol. 49, 430). Valid conclusions about the relative importance of time or dose-rate could not be based on this data. The reply, from one of the authors of the original paper, accepts many of the errata, and enumerates the changes which should be made. Replotting dose-treatment time and dose-dose rate does not however invalidate the conclusion that dose-rate is more important than time in analysing the risk of normal tissue injury. It is not claimed that the Strandqvist separation line in the dose-dose rate plane is better than in the dose-time plane. An improved definition of a region of low injury risk is given by a horizontal line at 4500 rad maximum dose and a vertical line at 60 rad/h maximum dose-rate on the dose-dose rate plot. Dose-rate is expected to be more important than time as a modifying factor of dose, both on the basis of radiobiological data and of clinical experience. Radiotherapists must balance the risks of radiotherapy-tumour recurrence with those of normal tissue injury, and increased attention should therefore be paid to regions of high and low dose-rate. (U.K.)

  20. Specific inhibition of Wee1 kinase and Rad51 recombinase: A strategy to enhance the sensitivity of leukemic T-cells to ionizing radiation-induced DNA double-strand breaks

    International Nuclear Information System (INIS)

    Havelek, Radim; Cmielova, Jana; Kralovec, Karel; Bruckova, Lenka; Bilkova, Zuzana; Fousova, Ivana; Sinkorova, Zuzana; Vavrova, Jirina; Rezacova, Martina

    2014-01-01

    Highlights: • Pre-treatment with the inhibitors increased the sensitivity of Jurkat cells to irradiation. • Combining both inhibitors together resulted in a G2 cell cycle arrest abrogation in Jurkat. • Jurkat cells pre-treated with inhibitors were positive for γH2AX foci 24 h upon irradiation. • Pre-treatment with Rad51 RI-1 had no effect on apoptosis induction in MOLT-4 cells. • When dosed together, the combination decreased MOLT-4 cell survival. - Abstract: Present-day oncology sees at least two-thirds of cancer patients receiving radiation therapy as a part of their anticancer treatment. The objectives of the current study were to investigate the effects of the small molecule inhibitors of Wee1 kinase II (681641) and Rad51 (RI-1) on cell cycle progression, DNA double-strand breaks repair and apoptosis following ionizing radiation exposure in human leukemic T-cells Jurkat and MOLT-4. Pre-treatment with the Wee1 681641 or Rad51 RI-1 inhibitor alone increased the sensitivity of Jurkat cells to irradiation, however combining both inhibitors together resulted in a further enhancement of apoptosis. Jurkat cells pre-treated with inhibitors were positive for γH2AX foci 24 h upon irradiation. MOLT-4 cells were less affected by inhibitors application prior to ionizing radiation exposure. Pre-treatment with Rad51 RI-1 had no effect on apoptosis induction; however Wee1 681641 increased ionizing radiation-induced cell death in MOLT-4 cells

  1. Resistance to RadLV-induced leukemia: non-participation of splenic natural killer cells

    International Nuclear Information System (INIS)

    St-Pierre, Y.; Hugo, P.; Lemieux, S.; Lussier, G.; Potworowski, E.F.

    1988-01-01

    The phenotypic expression of genetically determined resistance to radiation leukemia virus (RadLV)-induced leukemia in mice has been shown to reside in the bone marrow. Because the bone marrow contains precursors of natural killer (NK) cells, known to play a role in retrovirally induced infections, and because these cells have been suggested as participating in resistance to radiation-induced leukemia, it was pertinent to establish whether their levels differed in strains of mice susceptible and resistant to leukemia. We therefore tested splenic NK cell levels in C57BL/Ka (susceptible) and B10.A(5R) (resistant) mice before viral inoculation, immediately after viral inoculation, and throughout the preleukemic period and showed that they were not different. This indicates that splenic NK cell levels have no bearing on the resistance to RadLV-induced leukemia and that other immune or non-immune mechanisms must be sought

  2. Co-design of RAD and ETHICS methodologies: a combination of information system development methods

    Science.gov (United States)

    Nasehi, Arezo; Shahriyari, Salman

    2011-12-01

    Co-design is a new trend in the social world which tries to capture different ideas in order to use the most appropriate features for a system. In this paper, co-design of two information system methodologies is regarded; rapid application development (RAD) and effective technical and human implementation of computer-based systems (ETHICS). We tried to consider the characteristics of these methodologies to see the possibility of having a co-design or combination of them for developing an information system. To reach this purpose, four different aspects of them are analyzed: social or technical approach, user participation and user involvement, job satisfaction, and overcoming change resistance. Finally, a case study using the quantitative method is analyzed in order to examine the possibility of co-design using these factors. The paper concludes that RAD and ETHICS are appropriate to be co-designed and brings some suggestions for the co-design.

  3. Impurity incorporation in R.A.D. polysilicon layers and consequences on their electrical properties

    International Nuclear Information System (INIS)

    Revel, G.; Deschamps, N.; Deville, J.P.; Texier-Hervo, C.; Belouet, C.

    1982-01-01

    The growth of polysilicon layers by direct freezing of a film on a carbon ribbon by the RAD process goes along with a contamination of the silicon melt by carbon and its compositional impurities. This paper reports on this contamination effect studied mainly by means of neutron activation analyses (NAA) and its consequences on the electrical properties of the layers. The purification of the carbon ribbons in chlorine at high temperatures results in low contamination levels of the melt; NAA evidenced a significant segregation at the growth front, the effective partition coefficients determined being in the 10 - 1 to 10 - 3 range. Even though impurities are shown to impair the device performances, it is concluded that they are not necessarily incorporated in an electrically active form. Finally, AM 1 conversion efficiencies of 12% are reported for RAD cells 4 cm 2 in size. (Auth.)

  4. Melting decontamination and free release of metal waste at Studsvik RadWaste Co. in Sweden

    International Nuclear Information System (INIS)

    Kawatsuma, Shinji; Ishikawa, Keiji; Matsubara, Tatsuo; Donomae, Yasushi; Imagawa, Yasuhiro

    2006-01-01

    The Studsvik RadWaste Co. in Sweden was visited on August 29, 2005 by members of radioactive waste and decommissioning subgroup of central safety task force in old Japan Nuclear Cycle Development Institute as 'Overseas investigation'. The visit afforded us the chance to survey melting and decontaminating of metallic waste in this company and the status of free release. Domestic and foreign radioactive metallic waste is accepted in this company after 1987, and the majority of the decontaminated waste have been released freely. In the background of the big effort of this company and the strong leadership of the regulator (SSI: Swedish radiation protection Authority), prosperous operation was able to have been achieved. This survey was done based on 'Free release of radioactive metallic waste in Europe: the free release experience for 17 years at Studsvik RadWaste Co. in Sweden' by Dr. J. Lorenzen. (author)

  5. Dihydrocoumarin, an HDAC Inhibitor, Increases DNA Damage Sensitivity by Inhibiting Rad52

    Directory of Open Access Journals (Sweden)

    Chin-Chuan Chen

    2017-12-01

    Full Text Available Effective DNA repair enables cancer cells to survive DNA damage induced by chemotherapeutic or radiotherapeutic treatments. Therefore, inhibiting DNA repair pathways is a promising therapeutic strategy for increasing the efficacy of such treatments. In this study, we found that dihydrocoumarin (DHC, a flavoring agent, causes deficiencies in double-stand break (DSB repair and prolonged DNA damage checkpoint recovery in yeast. Following DNA damage, Rad52 recombinase was revealed to be inhibited by DHC, which results in deficiencies in DSB repair and prolonged DNA damage checkpoint recovery. The deletion of RPD3, a class I histone deacetylase (HDAC, was found to mimic DHC-induced suppression of Rad52 expression, suggesting that the HDAC inhibitor activity of DHC is critical to DSB repair and DNA damage sensitivity. Overall, our findings delineate the regulatory mechanisms of DHC in DSB repair and suggest that it might potentially be used as an inhibitor of the DNA repair pathway in human cells.

  6. RadSim: a program to simulate individual particle interactions for educational purposes

    International Nuclear Information System (INIS)

    Verhaegen, Frank; Palefsky, Steven; DeBlois, Francois

    2006-01-01

    A program was developed, RadSim, which can be used to simulate certain individual interactions of photons, electrons, positrons and alpha particles with a single atom for educational purposes. The program can be run in two modes: manual and simulated. In the manual mode, an individual particle undergoing a specified interaction with a target atom can be simulated, which essentially comes down to a graphical evaluation of kinematic equations. In the simulated mode, a preset number of identical particles are allowed to undergo a specified interaction type with a target atom. The exit channel of the interaction is sampled from probability distributions using Monte Carlo methods. The incoming and outgoing particles are visualized and the frequency distribution of the kinematic variables of the exit channel is displayed graphically. It has to be emphasized that RadSim was mainly developed for educational purposes. (note)

  7. Comparison between rad-hard standard float zone (FZ) and magnetic Czochralski (MCZ) silicon diodes in radiotherapy electron beam dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Santos, T.C. dos; Goncalves, J.A.C.; Vasques, M.M.; Tobias, C.C.B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Tecnologia das Radiacoes; Neves-Junior, W.F.P.; Haddad, C.M.K. [Hospital Sirio Libanes, Sao Paulo, SP (Brazil). Sociedade Beneficente de Senhoras; Harkonen, J. [Helsinki University of Technology (Denmark). Helsinki Inst. of Physics

    2010-07-01

    Full text. The use of semiconductor detectors has increased in radiotherapy practice since 1980s due to mainly their fast processing time, small sensitive volume and high relative sensitivity to ionizing radiation. Other major advantages of Si devices are excellent repeatability, good mechanical stability, high spatial resolution and the energy independence of mass collision stopping powers ratios (between silicon and water for electron beams with energy from 4 up to 20 MeV). However, ordinary silicon devices are very prone to radiation damage effects. In the last years, the development of radiation tolerant silicon detectors for High Energy Physics experiments has overcome this drawback. In this work we present the preliminary results obtained with a rad-hard epitaxial silicon diode as on-line clinical electron beam dosimeter. The diodes with 25 mm{sup 2} active area, were housed in a PMMA probe and connected, in a photovoltaic mode, to a Keithley 6517B electrometer. During all measurements, the diodes were held between PMMA plates, placed at Zref and centered in a radiation field of 10 cm x 10 cm, with the SSD kept at 100 cm. The devices dosimetric response was evaluated for 6, 9, 12, 15, 18 e 21 MeV electron beams from a Siemens KD 2 Radiotherapy Linear Accelerator, located at Sirio-Libanes Hospital. The radiation induced current in the diodes was registered as a function of the exposure time during 60 s for a fixed 300 MU. To study the short term repeatability, current signals were registered for the same radiation dose, for all energies. The dose-response of the diodes was achieved through the integration of the current signals as a function of the exposure time. The results obtained in the energy range of 6 up to 21 MeV evidenced that, for the same average dose rate of 5.0 cGy/s, the current signals are very stable and repeatable in both cases. For all energies, data shows good instantaneous repeatability with a percentage variation coefficient better than 2

  8. Could ultrasonic elastography help the diagnosis of small (≤2 cm) breast cancer with the usage of sonographic BI-RADS classification?

    International Nuclear Information System (INIS)

    Zhi, Hui; Xiao, Xiao-yun; Ou, Bing; Zhong, Wen-jing; Zhao, Zi-zhuo; Zhao, Xin-bao; Yang, Hai-yun; Luo, Bao-ming

    2012-01-01

    Objectives: To evaluate the additive value of ultrasound strain elastography (USE) to BI-RADS for the differentiation of benign and malignant breast small lesions. Methods: Breast masses (≤2 cm) with histological diagnosis examined by ultrasonography and USE in our department from April 2004 to December 2009 were reviewed. Conventional B-mode ultrasound findings were classified according to the BI-RADS classification. USE findings were classified according to the 5-point scale. Histological diagnosis was used as the reference standard. Results: 401 (246 benign (61.3%), 155 malignant (38.7%)) from 370 consecutive patients were included in the study. Sensitivity and specificity were 90.3%, 68.3% for BI-RADS; 72.3%, 91.9% for USE. The sensitivity of BI-RADS was better than that of USE (P < 0.05), while the specificity of USE was better than that of BI-RADS (P < 0.05). A revised BI-RADS combined with USE results was proposed in this study. Sensitivity and specificity were 83.9% and 87.8% for revised BI-RADS. The diagnostic performance of revised BI-RADS was better than BI-RADS (P < 0.05). Conclusions: USE could give BI-RADS some help in the differentiation of benign and malignant breast small lesions. The addition of elastography to BI-RADS could improve the diagnostic performance in <2 cm lesions.

  9. The Saccharomyces cerevisiae RAD18 gene encodes a protein that contains potential zinc finger domains for nucleic acid binding and a putative nucleotide binding sequence

    Energy Technology Data Exchange (ETDEWEB)

    Jones, J.S.; Prakash, L. (Univ. of Rochester School of Medicine, NY (USA)); Weber, S. (Kodak Research Park, Rochester, NY (USA))

    1988-07-25

    The RAD18 gene of Saccharomyces cerevisiae is required for postreplication repair of UV damaged DNA. The authors have isolated the RAD18 gene, determined its nucleotide sequence and examined if deletion mutations of this gene show different or more pronounced phenotypic effects than the previously described point mutations. The RAD18 gene open reading frame encodes a protein of 487 amino acids, with a calculated molecular weight of 55,512. The RAD18 protein contains three potential zinc finger domains for nucleic acid binding, and a putative nucleotide binding sequence that is present in many proteins that bind and hydrolyze ATP. The DNA binding and nucleotide binding activities could enable the RAD18 protein to bind damaged sites in the template DNA with high affinity. Alternatively, or in addition, RAD18 protein may be a transcriptional regulator. The RAD18 deletion mutation resembles the previously described point mutations in its effects on viability, DNA repair, UV mutagenesis, and sporulation.

  10. RadLex - German version: a radiological lexicon for indexing image and report information

    International Nuclear Information System (INIS)

    Marwede, D.; Lobsien, D.; Kahn, T.; Daumke, P.; Marko, K.; Schulz, S.

    2009-01-01

    Purpose: Since 2003 the Radiological Society of North America (RSNA) has been developing a lexicon of standardized radiological terms (RadLex) intended to support the structured reporting of imaging observations and the indexing of teaching cases. The aim of this study was to translate the first version of the lexicon (1 - 2007) into German and to implement a language-independent online term browser. Materials and Methods: RadLex version 1 - 2007 contains 6303 terms in nine main categories. Two radiologists independently translated the lexicon using medical dictionaries. Terms translated differently were revised and translated by consensus. For the development of an online term browser, a text processing algorithm called morphosemantic indexing was used which splits up words into small semantic units and compares those units to language-specific subword thesauri. Results: In total 6240 of 6303 terms (99 %) were translated. Of those terms 3965 were German, 1893 were Latin, 359 were multilingual, and 23 were English terms that are also used in German and were therefore maintained. The online term browser supports a language-independent term search in RadLex (German/English) and other common medical terminology (e.g., ICD 10). The term browser displays term hierarchies and translations in different frames and the complexity of the result lists can be adapted by the user. Conclusion: RadLex version 1 - 2007 developed by the RSNA is now available in German and can be accessed online through a term browser with an efficient search function. This is an important precondition for the future comparison of national and international indexed radiological examination results and the interoperability between digital teaching resources. (orig.)

  11. Rad-Tolerant, Thermally Stable, High-Speed Fiber-Optic Network for Harsh Environments

    Science.gov (United States)

    Leftwich, Matt; Hull, Tony; Leary, Michael; Leftwich, Marcus

    2013-01-01

    Future NASA destinations will be challenging to get to, have extreme environmental conditions, and may present difficulty in retrieving a spacecraft or its data. Space Photonics is developing a radiation-tolerant (rad-tolerant), high-speed, multi-channel fiber-optic transceiver, associated reconfigurable intelligent node communications architecture, and supporting hardware for intravehicular and ground-based optical networking applications. Data rates approaching 3.2 Gbps per channel will be achieved.

  12. PI-RADS classification. Structured reporting for MRI of the prostate

    International Nuclear Information System (INIS)

    Roethke, Matthias; Schlemmer, H.P.; Blondin, D.; Franiel, T.

    2013-01-01

    Purpose: To flesh out the ESUR guidelines for the standardized interpretation of multiparametric magnetic resonance imaging (mMRI) for the detection of prostate cancer and to present a graphic reporting scheme for improved communication of findings to urologists. Materials and Methods: The ESUR has recently published a structured reporting system for mMRI of the prostate (PI-RADS). This system involves the use of 5-point Likert scales for grading the findings obtained with different MRI techniques. The mMRI includes T2-weighted MRI, diffusion-weighted imaging, dynamic contrast-enhanced MRI, and MR spectroscopy. In a first step, the fundamentals of technical implementation were determined by consensus, taking into account in particular the German-speaking community. Then, representative images were selected by consensus on the basis of examinations of the three institutions. In addition, scoring intervals for an aggregated PI-RADS score were determined in consensus. Results: The multiparametric methods were discussed critically with regard to implementation and the current status. Criteria used for grading mMRI findings with the PI-RADS classification were concretized by succinct examples. Using the consensus table for aggregated scoring in a clinical setting, a diagnosis of suspected prostate cancer should be made if the PI-RADS score is 4 or higher (≥ 10 points if 3 techniques are used or ≥ 13 points if 4 techniques are used). Finally, a graphic scheme was developed for communicating mMRI prostate findings. Conclusion: Structured reporting according to the ESUR guidelines contributes to quality assurance by standardizing prostate mMRI, and it facilities the communication of findings to urologists. (orig.)

  13. Diagnostic value of BI-RADS categories in the management of patients with benign breast pathology

    Directory of Open Access Journals (Sweden)

    G. P. Korzhenkova

    2016-01-01

    Full Text Available Reasonable tactics of management of the patients with breast disease depends of the quality of diagnostics methods. Modern requirements to the methods of diagnosis – a precision, high information value, accessibility. In the article BI-RADS (Breast Imaging Reporting and Data System is being discussed. This system is a good tool to determine the proper algorithm of breast disease patients’ management.

  14. El gas radón como contaminante atmosférico

    Directory of Open Access Journals (Sweden)

    Luis Santiago Quindós Poncela

    2010-12-01

    Full Text Available En este trabajo se abordan distintos aspectos acerca de la problemática del radón en viviendas. Este gas de origen natural se encuentra prácticamente en la totalidad de los suelos de la corteza terrestre debido a la presencia de uranio y radio en la composición de los mismos. En función de factores arquitectónicos y de hábitos de ocupación de la vivienda pueden alcanzarse concentraciones elevadas del gas en interiores. En estas situaciones existe un incremento cuantificable del riesgo de desarrollar cáncer de pulmón en los habitantes de la vivienda. En los últimos años, las mejoras metodológicas en la realización de estudios epidemiológicos han conducido a la obtención de evidencias científicas de la relación entre la presencia de radón en interiores y el riesgo de cáncer de pulmón. Esta relación, encontrada hace años en trabajadores de minas de uranio, ha sido corroborada en el caso del radón residencial a la luz de los metaanálisis realizados recientemente a partir de estudios epidemiológicos agrupados. Durante los últimos 25 años se han realizado más de 6.000 medidas de radón en interiores. Se presentan los principales resultados de las mayores campañas de medida llevadas a cabo, así como los criterios recientemente establecidos por el Consejo de Seguridad Nuclear acerca de los niveles de intervención en viviendas y lugares de trabajo.

  15. Breast imaging and reporting data system - Mammography. ACR BI-RADS registered -Mammography

    International Nuclear Information System (INIS)

    Fischer, U.; Helbrich, T.

    2006-01-01

    ACR BI-RADS registered mammography is an established technique in all German-speaking countries and has become a standard part of all mammographic findings. The first German-language edition three years ago made a significant contribution to this. This is the second, revised and edited edition. It is based on the fourth English-language edition of the ACR which was published in 2003. (orig.)

  16. Prebiopsy biparametric MRI: differences of PI-RADS version 2 in patients with different PSA levels.

    Science.gov (United States)

    Choi, M H; Lee, Y J; Jung, S E; Rha, S E; Byun, J Y

    2018-06-09

    To validate the diagnostic accuracy of Prostate Imaging-Reporting and Data System (PI-RADS) version 2 in detecting clinically significant prostate cancer (csPCa, Gleason score ≥7) on prebiopsy biparametric MRI (bpMRI) in patients with different prostate-specific antigen (PSA) levels. This retrospective study included 184 patients who underwent prebiopsy bpMRI followed by transrectal ultrasonography-guided biopsy between June 2015 and February 2017. Reader 1 performed a combination of systematic and targeted biopsy with cognitive fusion after reviewing bpMRI and reader 2 reviewed the bpMRIs retrospectively. PI-RADS categories 4 and 5 were considered positive, and the results of the biopsy were considered the reference standard. Diagnostic performance of PI-RADS of bpMRI was evaluated in two PSA groups with a PSA cut-off level of 10 ng/ml and compared to PSA and the PSA density using receiver operating characteristics (ROC) curve analysis. csPCa was diagnosed in 24 of 123 patients (19.5%) and 26 of 61 patients (42.6%) in the low and high PSA groups, respectively. A PI-RADS v2 category by either readers 1 or 2 had a significantly better performance to detect csPCa than PSA in both PSA groups. In the high PSA group, only one csPCa was missed by reader 2, but none by reader 1. In the low PSA group, readers 1 and 2 were unable to detect seven and five of the 24 csPCas, respectively. Prebiopsy bpMRI has good performance for detecting csPCa in the high PSA group but may miss small-volume csPCa in the low PSA group. Copyright © 2018 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  17. Diagrams about RA reactor operation, Annex 7; Prilog 7 - Rad reaktora RA po godinama - dijagrami

    Energy Technology Data Exchange (ETDEWEB)

    Martinc, R [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Serbia and Montenegro)

    1976-01-15

    This Annex 7 includes diagrams about RA reactor operation (MWh) from 1960-1975; mean values of reactor power per day and month in 1975, and percent of utilisation of experimental space during 1975. [Serbo-Croat] Ovaj prilog sadrzi dijagrame o radu reaktora (MWh) po godinama (1960-1975); srednje vrednosti dnevne snage reaktora u 1975. godini; rad reakrora (MWh) po mesecima u 1975; procenat iskoriscenja eksperimentalnog prostora u 1975. godini.

  18. Parallel Study of HEND, RAD, and DAN Instrument Response to Martian Radiation and Surface Conditions

    Science.gov (United States)

    Martiniez Sierra, Luz Maria; Jun, Insoo; Litvak, Maxim; Sanin, Anton; Mitrofanov, Igor; Zeitlin, Cary

    2015-01-01

    Nuclear detection methods are being used to understand the radiation environment at Mars. JPL (Jet Propulsion Laboratory) assets on Mars include: Orbiter -2001 Mars Odyssey [High Energy Neutron Detector (HEND)]; Mars Science Laboratory Rover -Curiosity [(Radiation Assessment Detector (RAD); Dynamic Albedo Neutron (DAN))]. Spacecraft have instruments able to detect ionizing and non-ionizing radiation. Instrument response on orbit and on the surface of Mars to space weather and local conditions [is discussed] - Data available at NASA-PDS (Planetary Data System).

  19. A new e-learning platform for radiology education (RadEd).

    Science.gov (United States)

    Xiberta, Pau; Boada, Imma

    2016-04-01

    One of the key elements of e-learning platforms is the content provided to the students. Content creation is a time demanding task that requires teachers to prepare material taking into account that it will be accessed on-line. Moreover, the teacher is restricted by the functionalities provided by the e-learning platforms. In contexts such as radiology where images have a key role, the required functionalities are still more specific and difficult to be provided by these platforms. Our purpose is to create a framework to make teacher's tasks easier, specially when he has to deal with contents where images have a main role. In this paper, we present RadEd, a new web-based teaching framework that integrates a smart editor to create case-based exercises that support image interaction such as changing the window width and the grey scale used to render the image, taking measurements on the image, attaching labels to images and selecting parts of the images, amongst others. It also provides functionalities to prepare courses with different topics, exercises and theory material, and also functionalities to control students' work. Different experts have used RadEd and all of them have considered it a very useful and valuable tool to prepare courses where radiological images are the main component. RadEd provides teachers functionalities to prepare more realistic cases and students the ability to make a more specific diagnosis. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  20. A RAD-based phylogenetics for Orestias fishes from Lake Titicaca.

    Science.gov (United States)

    Takahashi, Tetsumi; Moreno, Edmundo

    2015-12-01

    The fish genus Orestias is endemic to the Andes highlands, and Lake Titicaca is the centre of the species diversity of the genus. Previous phylogenetic studies based on a single locus of mitochondrial and nuclear DNA strongly support the monophyly of a group composed of many of species endemic to the Lake Titicaca basin (the Lake Titicaca radiation), but the relationships among the species in the radiation remain unclear. Recently, restriction site-associated DNA (RAD) sequencing, which can produce a vast number of short sequences from various loci of nuclear DNA, has emerged as a useful way to resolve complex phylogenetic problems. To propose a new phylogenetic hypothesis of Orestias fishes of the Lake Titicaca radiation, we conducted a cluster analysis based on morphological similarities among fish samples and a molecular phylogenetic analysis based on RAD sequencing. From a morphological cluster analysis, we recognised four species groups in the radiation, and three of the four groups were resolved as monophyletic groups in maximum-likelihood trees based on RAD sequencing data. The other morphology-based group was not resolved as a monophyletic group in molecular phylogenies, and some members of the group were diverged from its sister group close to the root of the Lake Titicaca radiation. The evolution of these fishes is discussed from the phylogenetic relationships. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. It should be indicate a biopsy for BI-RADS 3 mammogram?

    Directory of Open Access Journals (Sweden)

    Anahi Ofelia Vera San Miguel

    2016-12-01

    Full Text Available Background: Worldwide, mammography is the imaging method most commonly used for early detection of breast cancer, decisive for prior to the onset of symptoms diagnosed. The malignancy that is recorded more frequently in women is breast cancer, regarded worldwide as a major public health problem. By implementing the BI-RADS manual seeks to standardize mammographic report. Objective: To determine the radiographic and anatomic-pathologic concordance of mammographic findings in women of thirty years and more, who consulted in the Hospital Central del Instituto de Previsión Social- Paraguay, during the first semester of 2015. Materials and Methods: We performed a cross-sectional, retrospective study. The variables age, reasons for seeing a doctor, mammographic findings, histopathological diagnoses obtained from breast biopsy and reporting BI-RADS were studied. Results: The sample consisted of 138 women. The age range of the patients was 30 to 89 years, with an average of 55 years. The annual routine check represented the most frequent reason for consultation (52.0%. 71.0% of the findings corresponded to dense nodules, and they were 75.0% malignancies. Conclusion: The agreement was moderate with Kappa index. In patients with BI-RADS 3, there were found 30.62% malignancies, so it is suggested to consider from this level for pathological study.

  2. Intraobserver interpretation of breast ultrasonography following the BI-RADS classification

    International Nuclear Information System (INIS)

    Calas, M.J.G.; Almeida, R.M.V.R.; Gutfilen, B.; Pereira, W.C.A.

    2010-01-01

    Purpose: To use the BI-RADS ultrasound classification in an intraobserver retrospective study of the interpretation of breast images. Materials and Methods: The study used 40 breast ultrasound images recorded in orthogonal planes, obtained from patients with an indication for surgery. Eight professionals experienced in breast imaging analysis retrospectively reviewed these lesions, in three rounds of image interpretation (with a 3-6 months interval between rounds). Observers had no access to information from medical records or histopathological results, and, without their knowledge, in each new round were assigned the same images previously interpreted by them. Fleiss-modified Kappa measures were the study main concordance index. Besides the BI-RADS, a scale grouping its categories 2-3 and 4-5 was also used. The statistical analysis concerned the intraobserver agreement. Results: Kappa values ranged from 0.37 to 0.75 (original categories) and from 0.73 to 0.87 (grouped categories). Overall, out of the 8 observers, 7 presented moderate to substantial concordance (Kappa values 0.51 to 0.74). Conclusion: The BI-RADS is a reporting tool that provides a standardized terminology for US exams. In this study, moderate to substantial concordance in Kappa values was found, in agreement with other studies of the literature.

  3. Radionuclide field lysimeter experiment (RadFLEx): geochemical and hydrological data for SRS performance assessments

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Powell, B. [Clemson Univ., SC (United States); Barber, K. [Clemson Univ., SC (United States); Devol, T. [Clemson Univ., SC (United States); Dixon, K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Erdmann, B. [Clemson Univ., SC (United States); Maloubier, M. [Clemson Univ., SC (United States); Martinez, N. [Clemson Univ., SC (United States); Montgomery, D. [Clemson Univ., SC (United States); Peruski, K. [Clemson Univ., SC (United States); Roberts, K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Witmer, M. [Clemson Univ., SC (United States)

    2017-12-12

    The SRNL Radiological Field Lysimeter Experiment (RadFLEx) is a one-of-a-kind test bed facility designed to study radionuclide geochemical processes in the Savannah River Site (SRS) vadose zone at a larger spatial scale (from grams to tens of kilograms of sediment) and temporal scale (from months to decade) than is readily afforded through laboratory studies. RadFLEx is a decade-long project that was initiated on July 5, 2012 and is funded by six different sources. The objective of this status report is as follows: 1) to report findings to date that have an impact on SRS performance assessment (PA) calculations, and 2) to provide performance metrics of the RadFLEx program. The PA results are focused on measurements of transport parameters, such as distribution coefficients (Kd values), solubility, and unsaturated flow values. As this is an interim report, additional information from subsequent research may influence our interpretation of current results. Research related to basic understanding of radionuclide geochemistry in these vadose zone soils and other source terms are not described here but are referenced for the interested reader.

  4. Experimental technique to measure thoron generation rate of building material samples using RAD7 detector

    International Nuclear Information System (INIS)

    Csige, I.; Szabó, Zs.; Szabó, Cs.

    2013-01-01

    Thoron ( 220 Rn) is the second most abundant radon isotope in our living environment. In some dwellings it is present in significant amount which calls for its identification and remediation. Indoor thoron originates mainly from building materials. In this work we have developed and tested an experimental technique to measure thoron generation rate in building material samples using RAD7 radon-thoron detector. The mathematical model of the measurement technique provides the thoron concentration response of RAD7 as a function of the sample thickness. For experimental validation of the technique an adobe building material sample was selected for measuring the thoron concentration at nineteen different sample thicknesses. Fitting the parameters of the model to the measurement results, both the generation rate and the diffusion length of thoron was estimated. We have also determined the optimal sample thickness for estimating the thoron generation rate from a single measurement. -- Highlights: • RAD7 is used for the determination of thoron generation rate (emanation). • The described model takes into account the thoron decay and attenuation. • The model describes well the experimental results. • A single point measurement method is offered at a determined sample thickness

  5. Masimo Rad-57 Pulse CO-Oximeter for noninvasive carboxyhemoglobin measurement.

    Science.gov (United States)

    Suner, Selim; McMurdy, John

    2009-03-01

    Noninvasive methods of body fluid chemical measurement have been expanding. New technologies are enabling the quantification of different compounds in the blood and interstitial tissues. One example of this is the pulse oximeter, which has facilitated the measurement of oxyhemoglobin rapidly and reliably without the requirement of blood-draws. The Masimo Rad-57 Pulse CO-Oximeter expanded the capabilities of pulse-oximetry to include measurements of carboxyhemoglobin and methemoglobin. This innovation has revolutionized the paradigm for detection of patients with CO poisoning. Previously, clinicians relied on historical information and patient signs and symptoms pointing to the possibility of CO exposure or toxicity. Only then would a blood test be ordered to measure carboxyhemoglobin levels. Since the presentation of CO poisoning is nonspecific and overlaps with many other conditions, and since the presence of environmental CO is often unknown, the detection of this condition was only possible in cases where the presence of CO was obvious or where the symptoms were severe. We now know, from studies conducted using the Rad-57, the only US FDA-approved device for noninvasive measurement of SpCO, that there are a significant number of patients who experience CO exposure but are nonsymptomatic. The Rad-57 provides a clinical justification for screening in the healthcare setting to identify patients with significant CO exposure who would otherwise be undetected.

  6. Diagnostic SNPs for inferring population structure in American mink (Neovison vison) identified through RAD sequencing

    DEFF Research Database (Denmark)

    2015-01-01

    Data from: "Diagnostic SNPs for inferring population structure in American mink (Neovison vison) identified through RAD sequencing" in Genomic Resources Notes accepted 1 October 2014 to 30 November 2014....

  7. Significance of lenticular opacity from the view point of the exposure dose of A-bomb radiation

    Energy Technology Data Exchange (ETDEWEB)

    Sugimoto, S [Sugimoto Hospital, Hiroshima (Japan)

    1975-04-01

    Two cases of lenticular opacity were discussed from the view point of exposure dose of A-bomb radiation. Case 1: female, 22 year and 5 months old when she was exposured to A-bomb radiation. The presumed exposure dose was 482.0 rad. Cataract due to A-bomb radiation. Case 2: female, 21 years and 6 months old when she was exposured to A-bomb radiation. The presumed exposure dose was more than 1,000 rad. Cataract due to A-bomb radiation and incipient cataract senilis. It was reported here that there was a marked difference in opacity findings of cataract due to A-bomb radiation in accordance with difference in exposure dose of radiation. It was also presumed from the findings of incipient cataract senilis that with increasing exposure dose, the aging phenomenon was promoted.

  8. Genetic Interactions Between the Meiosis-Specific Cohesin Components, STAG3, REC8, and RAD21L.

    Science.gov (United States)

    Ward, Ayobami; Hopkins, Jessica; Mckay, Matthew; Murray, Steve; Jordan, Philip W

    2016-06-01

    Cohesin is an essential structural component of chromosomes that ensures accurate chromosome segregation during mitosis and meiosis. Previous studies have shown that there are cohesin complexes specific to meiosis, required to mediate homologous chromosome pairing, synapsis, recombination, and segregation. Meiosis-specific cohesin complexes consist of two structural maintenance of chromosomes proteins (SMC1α/SMC1β and SMC3), an α-kleisin protein (RAD21, RAD21L, or REC8), and a stromal antigen protein (STAG1, 2, or 3). STAG3 is exclusively expressed during meiosis, and is the predominant STAG protein component of cohesin complexes in primary spermatocytes from mouse, interacting directly with each α-kleisin subunit. REC8 and RAD21L are also meiosis-specific cohesin components. Stag3 mutant spermatocytes arrest in early prophase ("zygotene-like" stage), displaying failed homolog synapsis and persistent DNA damage, as a result of unstable loading of cohesin onto the chromosome axes. Interestingly, Rec8, Rad21L double mutants resulted in an earlier "leptotene-like" arrest, accompanied by complete absence of STAG3 loading. To assess genetic interactions between STAG3 and α-kleisin subunits RAD21L and REC8, our lab generated Stag3, Rad21L, and Stag3, Rec8 double knockout mice, and compared them to the Rec8, Rad21L double mutant. These double mutants are phenotypically distinct from one another, and more severe than each single knockout mutant with regards to chromosome axis formation, cohesin loading, and sister chromatid cohesion. The Stag3, Rad21L, and Stag3, Rec8 double mutants both progress further into prophase I than the Rec8, Rad21L double mutant. Our genetic analysis demonstrates that cohesins containing STAG3 and REC8 are the main complex required for centromeric cohesion, and RAD21L cohesins are required for normal clustering of pericentromeric heterochromatin. Furthermore, the STAG3/REC8 and STAG3/RAD21L cohesins are the primary cohesins required for

  9. Properties of cellulose triacetate dose meter

    International Nuclear Information System (INIS)

    Tamura, N.; Tanaka, R.; Mitomo, S.; Matsuda, K.; Nagai, S.

    1981-01-01

    Several clear plastics and dyed plastics are commercially available for dosimetry in intense radiation field, especially for radiation processing applications. Among these dose meters cellulose triacetate (CTA) dose meter has two advantages for routine uses; (1) it has linear response in mega-rad dose region and (2) the main product form is long tape. However, the manufacture of Numelec CTA film so far used had been discontinued, and for this reason we developed a new film for dosimetry uses. To determine the manufacturing conditions of the film, we examined the influence of additives, triphenylphosphate (TPP) and others, and film thickness on the dosimetric properties, since these two conditions remarkably influence the sensitivity of the dose meter. It is necessary for the reliability of plastic dose meters that the radiation induced colorations should be understood as radiation chemical processes. In this paper we describe the determination of the manufacturing conditions of the new film, the feature of the new dose meter, and the coloration mechanism. (author)

  10. Dose calculations using artificial neural networks: A feasibility study for photon beams

    Science.gov (United States)

    Vasseur, Aurélien; Makovicka, Libor; Martin, Éric; Sauget, Marc; Contassot-Vivier, Sylvain; Bahi, Jacques

    2008-04-01

    Direct dose calculations are a crucial requirement for Treatment Planning Systems. Some methods, such as Monte Carlo, explicitly model particle transport, others depend upon tabulated data or analytic formulae. However, their computation time is too lengthy for clinical use, or accuracy is insufficient, especially for recent techniques such as Intensity-Modulated Radiotherapy. Based on artificial neural networks (ANNs), a new solution is proposed and this work extends the properties of such an algorithm and is called NeuRad. Prior to any calculations, a first phase known as the learning process is necessary. Monte Carlo dose distributions in homogeneous media are used, and the ANN is then acquired. According to the training base, it can be used as a dose engine for either heterogeneous media or for an unknown material. In this report, two networks were created in order to compute dose distribution within a homogeneous phantom made of an unknown material and within an inhomogeneous phantom made of water and TA6V4 (titanium alloy corresponding to hip prosthesis). All NeuRad results were compared to Monte Carlo distributions. The latter required about 7 h on a dedicated cluster (10 nodes). NeuRad learning requires between 8 and 18 h (depending upon the size of the training base) on a single low-end computer. However, the results of dose computation with the ANN are available in less than 2 s, again using a low-end computer, for a 150×1×150 voxels phantom. In the case of homogeneous medium, the mean deviation in the high dose region was less than 1.7%. With a TA6V4 hip prosthesis bathed in water, the mean deviation in the high dose region was less than 4.1%. Further improvements in NeuRad will have to include full 3D calculations, inhomogeneity management and input definitions.

  11. Dose calculations using artificial neural networks: A feasibility study for photon beams

    International Nuclear Information System (INIS)

    Vasseur, Aurelien; Makovicka, Libor; Martin, Eric; Sauget, Marc; Contassot-Vivier, Sylvain; Bahi, Jacques

    2008-01-01

    Direct dose calculations are a crucial requirement for Treatment Planning Systems. Some methods, such as Monte Carlo, explicitly model particle transport, others depend upon tabulated data or analytic formulae. However, their computation time is too lengthy for clinical use, or accuracy is insufficient, especially for recent techniques such as Intensity-Modulated Radiotherapy. Based on artificial neural networks (ANNs), a new solution is proposed and this work extends the properties of such an algorithm and is called NeuRad. Prior to any calculations, a first phase known as the learning process is necessary. Monte Carlo dose distributions in homogeneous media are used, and the ANN is then acquired. According to the training base, it can be used as a dose engine for either heterogeneous media or for an unknown material. In this report, two networks were created in order to compute dose distribution within a homogeneous phantom made of an unknown material and within an inhomogeneous phantom made of water and TA6V4 (titanium alloy corresponding to hip prosthesis). All NeuRad results were compared to Monte Carlo distributions. The latter required about 7 h on a dedicated cluster (10 nodes). NeuRad learning requires between 8 and 18 h (depending upon the size of the training base) on a single low-end computer. However, the results of dose computation with the ANN are available in less than 2 s, again using a low-end computer, for a 150x1x150 voxels phantom. In the case of homogeneous medium, the mean deviation in the high dose region was less than 1.7%. With a TA6V4 hip prosthesis bathed in water, the mean deviation in the high dose region was less than 4.1%. Further improvements in NeuRad will have to include full 3D calculations, inhomogeneity management and input definitions

  12. Dose calculations using artificial neural networks: A feasibility study for photon beams

    Energy Technology Data Exchange (ETDEWEB)

    Vasseur, Aurelien [University of Franche-Comte, IRMA/CREST Femto-ST, Portes du Jura, 4 place Tharradin, BP 71427, 25211 Montbeliard Cedex (France); University of Franche-Comte, AND/LIFC, rue Engel Gros, 90016 Belfort (France)], E-mail: aurelien.vasseur@gmail.com; Makovicka, Libor; Martin, Eric [University of Franche-Comte, IRMA/CREST Femto-ST, Portes du Jura, 4 place Tharradin, BP 71427, 25211 Montbeliard Cedex (France); Sauget, Marc [University of Franche-Comte, IRMA/CREST Femto-ST, Portes du Jura, 4 place Tharradin, BP 71427, 25211 Montbeliard Cedex (France); University of Franche-Comte, AND/LIFC, rue Engel Gros, 90016 Belfort (France); Contassot-Vivier, Sylvain; Bahi, Jacques [University of Franche-Comte, AND/LIFC, rue Engel Gros, 90016 Belfort (France)

    2008-04-15

    Direct dose calculations are a crucial requirement for Treatment Planning Systems. Some methods, such as Monte Carlo, explicitly model particle transport, others depend upon tabulated data or analytic formulae. However, their computation time is too lengthy for clinical use, or accuracy is insufficient, especially for recent techniques such as Intensity-Modulated Radiotherapy. Based on artificial neural networks (ANNs), a new solution is proposed and this work extends the properties of such an algorithm and is called NeuRad. Prior to any calculations, a first phase known as the learning process is necessary. Monte Carlo dose distributions in homogeneous media are used, and the ANN is then acquired. According to the training base, it can be used as a dose engine for either heterogeneous media or for an unknown material. In this report, two networks were created in order to compute dose distribution within a homogeneous phantom made of an unknown material and within an inhomogeneous phantom made of water and TA6V4 (titanium alloy corresponding to hip prosthesis). All NeuRad results were compared to Monte Carlo distributions. The latter required about 7 h on a dedicated cluster (10 nodes). NeuRad learning requires between 8 and 18 h (depending upon the size of the training base) on a single low-end computer. However, the results of dose computation with the ANN are available in less than 2 s, again using a low-end computer, for a 150x1x150 voxels phantom. In the case of homogeneous medium, the mean deviation in the high dose region was less than 1.7%. With a TA6V4 hip prosthesis bathed in water, the mean deviation in the high dose region was less than 4.1%. Further improvements in NeuRad will have to include full 3D calculations, inhomogeneity management and input definitions.

  13. Human cytogenetic dosimetry: a dose-response relationship for alpha particle radiation from 241Am

    International Nuclear Information System (INIS)

    DuFrain, R.J.; Littlefield, L.G.; Joiner, E.E.; Frome, E.L.

    1979-01-01

    Cytogenetic dosimetry estimates to guide treatment of persons internally contaminated with transuranic elements have not previously been possible because appropriate in vitro dose-response curves specifically for alpha particle irradiation of human lymphocytes do not exist. Using well-controlled cytogenetic methods for human lymphocyte culture, an experimentally derived dose-response curve for 241 Am alpha particle (5.49 and 5.44 MeV) radiation of G 0 lymphocytes was generated. Cells were exposed to 43.8, 87.7, 175.3 or 350.6 nCi/ml 241 Am for 1.7 hr giving doses of 0.85, 1.71, 3.42 or 6.84 rad. Based on dicentric chromosome yield, the linear dose-response equation is Y = 4.90(+-0.42) x 10 -2 X, with Y given as dicentrics per cell and X as dose in rads. The study also shows that the two-break asymmetrical exchanges in cells damaged by alpha particle radiation are overdispersed when compared to a Poisson distribution. An example is presented to show how the derived dose-response equation can be used to estimate the radiation dose for a person internally contaminated with an actinide. An experimentally derived RBE value of 118 at 0.85 rad is calculated for the efficiency of 241 Am alpha particle induction of dicentric chromosomes in human G 0 lymphocytes as compared with the efficiency of 60 Co gamma radiation. The maximum theoretical value for the RBE for cytogenetic damage from alpha irradiation was determined to be 278 at 0.1 rad or less which is in marked contrast to previously reported RBE values of approx. 20. (author)

  14. Breast Density Estimation with Fully Automated Volumetric Method: Comparison to Radiologists' Assessment by BI-RADS Categories.

    Science.gov (United States)

    Singh, Tulika; Sharma, Madhurima; Singla, Veenu; Khandelwal, Niranjan

    2016-01-01

    The objective of our study was to calculate mammographic breast density with a fully automated volumetric breast density measurement method and to compare it to breast imaging reporting and data system (BI-RADS) breast density categories assigned by two radiologists. A total of 476 full-field digital mammography examinations with standard mediolateral oblique and craniocaudal views were evaluated by two blinded radiologists and BI-RADS density categories were assigned. Using a fully automated software, mean fibroglandular tissue volume, mean breast volume, and mean volumetric breast density were calculated. Based on percentage volumetric breast density, a volumetric density grade was assigned from 1 to 4. The weighted overall kappa was 0.895 (almost perfect agreement) for the two radiologists' BI-RADS density estimates. A statistically significant difference was seen in mean volumetric breast density among the BI-RADS density categories. With increased BI-RADS density category, increase in mean volumetric breast density was also seen (P BI-RADS categories and volumetric density grading by fully automated software (ρ = 0.728, P BI-RADS density category by two observers showed fair agreement (κ = 0.398 and 0.388, respectively). In our study, a good correlation was seen between density grading using fully automated volumetric method and density grading using BI-RADS density categories assigned by the two radiologists. Thus, the fully automated volumetric method may be used to quantify breast density on routine mammography. Copyright © 2016 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  15. The researches on the effects of low doses irradiation

    International Nuclear Information System (INIS)

    2009-02-01

    All research conducted as part of 'Risc-Rad' and those conducted by actors in international programs on low doses allow progress in understanding mechanisms of carcinogenesis associated with irradiation. The data do not question the use in radiation protection, risk estimation models based on a linear increase of the risk with the dose of radiation. Nevertheless, they show that the nature of biological responses induced by low doses of radiation has differences with the responses induced by high doses of radiation. They also show the diversity of effects/dose relationships as the mechanism observed and the importance of genetic predisposition in the individual sensitivity to low doses of radiation. It is therefore essential to continue to bring new data to better understand the complex biological effects and their impact on the establishment of radiation protection standards. In addition, the results have often been at the cellular level. The diversity of responses induced by radiations is also a function of cell types observed, the aging of cells and tissue organization. It is essential to strengthen researches at the tissue and body level, involving in vitro and in vivo approaches while testing the hypothesis in epidemiology with a global approach to systems biology. Over the past four years, the collaboration between partners of 'Risc-Rad' using experimental biology approaches and those using mathematical modeling techniques aimed at developing a new model describing the carcinogenesis induced by low radiation doses. On an other hand, The High level expert group on European low dose risk research (H.L.E.G.) develop programmes in the area of low dose irradiation (Germany, Finland, France, Italy and United Kingdom). It proposed a structure of trans national government called M.E.L.O.D.I. ( multidisciplinary european low dose initiative). Its objective is to structure and integrate European research by gathering around a common programme of multidisciplinary

  16. Doses in mammography. Preliminary study

    International Nuclear Information System (INIS)

    Marquez P, F.; Acosta R, N.; Universidad Nacional Mayor de San Marcos, Lima; Benavente, T.; Universidad Nacional Mayor de San Marcos, Lima; Poma, M.

    2002-01-01

    Mammography is the most important method to detect lesions in the breast with this technique one can detect small tumours before clear clinical symptoms appear. Mammographic image of require high quality standards due that the extremely low contrast between the normal and pathological areas in the breast, eg.g., they have similar attenuation and absorption coefficient. The x-ray mammographic systems, used in this study are Senographe 500t and Senographe DMR, a detector with a RadCal ionization chambers calibrated to the qualities of mammographic x-ray beams, and a breast simulator that is a phantoms of polymethylmethacrylate (PMMA) of several thicknesses with the equivalence of 50% of the glandular tissue. The results obtained indicate that the values of doses at the entrance surface of a breast (DES) are greater the reference value 20 mGy to 5,0 cm of PMMA and the values of the mean glandular dose (MGD) exceed the reference value of 2,1 mGy for 5,1 cm of compressed thick breast. We consider that the values high of the EDS and MGD are due that the x-ray systems no meeting in good condition or for used of x-ray spectra no suitable, so is recommendable be carried out test of quality control to the x-ray systems and also realize studies, or characterize the of x-ray mammographic spectra

  17. Earley changes in cerebral blood flow following head exposure of rabbit at a mean absorbed dose of 1000 rads

    International Nuclear Information System (INIS)

    Dufour, Raymond.

    1978-10-01

    Observations were made on 5 animals after 12 head exposures. The local cerebral blood flow increased on the 1st hour and lasted during the following 15-20 h. Two particular responses were used to test cerebral vasotonicity: rate increases due to inhalation of CO 2 (5 p. cent CO 2 in air) and accompanying paradoxical sleep. Their decrease after irradiation was studied systematically by CO 2 tests whatever the rate level reached. These weaker increases were not the indication of an upper limit of the the rate, they also occurred when the rate fell back to its initial value. They appeared on the 2nd hour and lasted till the 48th hour. As a conclusion: head irradiation resulted in an early increase of cerebral blood flow lasting less than 24 h; the pattern of metabolic or myogenic regulation of intraparenchymatous vessels and neurogenic regulation of extraparenchymatous vessels would explain the observed phenomena better. The metabolic modifications of the irradiated tissue should result in vasodilation of intraparenchymatous vessels. The stimulating action of the neurovegetative centers would be shown by a decrease of the vessel responses to CO 2 at the level of the extraparenchymatous vessels [fr

  18. Controllable dose

    International Nuclear Information System (INIS)

    Alvarez R, J.T.; Anaya M, R.A.

    2004-01-01

    With the purpose of eliminating the controversy about the lineal hypothesis without threshold which found the systems of dose limitation of the recommendations of ICRP 26 and 60, at the end of last decade R. Clarke president of the ICRP proposed the concept of Controllable Dose: as the dose or dose sum that an individual receives from a particular source which can be reasonably controllable by means of any means; said concept proposes a change in the philosophy of the radiological protection of its concern by social approaches to an individual focus. In this work a panorama of the foundations is presented, convenient and inconveniences that this proposal has loosened in the international community of the radiological protection, with the purpose of to familiarize to our Mexican community in radiological protection with these new concepts. (Author)

  19. RAD9 deficiency enhances radiation induced bystander DNA damage and transcriptomal response

    International Nuclear Information System (INIS)

    Ghandhi, Shanaz A; Ponnaiya, Brian; Panigrahi, Sunil K; Hopkins, Kevin M; Cui, Qingping; Hei, Tom K; Amundson, Sally A; Lieberman, Howard B

    2014-01-01

    Radiation induced bystander effects are an important component of the overall response of cells to irradiation and are associated with human health risks. The mechanism responsible includes intra-cellular and inter-cellular signaling by which the bystander response is propagated. However, details of the signaling mechanism are not well defined. We measured the bystander response of Mrad9 +/+ and Mrad9 −/− mouse embryonic stem cells, as well as human H1299 cells with inherent or RNA interference-mediated reduced RAD9 levels after exposure to 1 Gy α particles, by scoring chromosomal aberrations and micronuclei formation, respectively. In addition, we used microarray gene expression analyses to profile the transcriptome of directly irradiated and bystander H1299 cells. We demonstrated that Mrad9 null enhances chromatid aberration frequency induced by radiation in bystander mouse embryonic stem cells. In addition, we found that H1299 cells with reduced RAD9 protein levels showed a higher frequency of radiation induced bystander micronuclei formation, compared with parental cells containing inherent levels of RAD9. The enhanced bystander response in human cells was associated with a unique transcriptomic profile. In unirradiated cells, RAD9 reduction broadly affected stress response pathways at the mRNA level; there was reduction in transcript levels corresponding to genes encoding multiple members of the UVA-MAPK and p38MAPK families, such as STAT1 and PARP1, suggesting that these signaling mechanisms may not function optimally when RAD9 is reduced. Using network analysis, we found that differential activation of the SP1 and NUPR1 transcriptional regulators was predicted in directly irradiated and bystander H1299 cells. Transcription factor prediction analysis also implied that HIF1α (Hypoxia induced factor 1 alpha) activation by protein stabilization in irradiated cells could be a negative predictor of the bystander response, suggesting that local hypoxic stress

  20. Diagnostic value of coustic radiation force impulse for BI-RADS category 4 breast lesions of different sizes.

    Science.gov (United States)

    Wu, Rong

    2018-04-14

    To determine the diagnostic value of combined conventional ultrasound (US) and acoustic radiation force impulse (ARFI) imaging for the differential diagnosis of BI-RADS category 4 breast lesions of different sizes. From April 2013 to January 2015, 283 patients (with a total of 292 breast lesions) who underwent US and ARFI examination were included in this retrospective study. The SWV for the lesion and adjacent normal breast tissue were measured and the SWV ratio was calculated. VTI grade was also assessed. The lesions were separated into three groups on the basis of size, and two combinations of ARFI parameters (SWV + VTI and SWV ratio + VTI) were applied to reassess the BI-RADS categories. Diagnoses were confirmed by pathological examination after biopsy or surgery. ROC analysis was performed to assess the diagnostic efficiency of each method. The Z test was used to compare the difference between AUC of the two methods. Significant improvement was seen in the diagnostic performance of US with the use of the ARFI parameters SWV + VTI (77/179 [43.0%] of BI-RADS category 4A breast lesions were downgraded) and SWV ratio + VTI (64/179 [35.8%] of BI-RADS category 4A breast lesions were downgraded, including two malignant cases that were misdiagnosed as benign) (P BI-RADS category 4 breast lesions. The combination of SWV ratio + VTI can improve BI-RADS classification of small lesions (<10 mm size).