Sample records for radiobiological application etude

  1. Single-Ion Microbeam for Applications in Radiobiology: State of the Art

    Hu Zhiwen; Wu Lijun; Yu Zengliang


    Single-Ion Microbeam (SIM) is uniquely capable of precisely delivering a predefined number of charged particles (precise doses of radiation) to individual cells or sub-cellular targets in situ. Since the early 1990's, there has been an ever-increasing interest in developing and applying the SIM technique to problems in radiobiology for studies of cell and tissue damaged by ionizing radiations. Potential applications for SIM in radiobiology continues to grow and have been diversified. There are currently more than 14 SIM facilities worldwide, and they have been in a constant state of evolution. This paper reviews the current state of SIM research worldwide and the related pivotal technological developments in the fields of both biophysics and radiobiology.Representative applications and the perspective of SIM are also introduced and discussed.

  2. Development of applicable software containing radiobiological and physical indices to evaluate radiotherapy planning

    Lee, Seu Ran; Suh, Tae Suk [Dept. of Biomedical Engineering, The Catholic University of Korea, Seoul (Korea, Republic of); Park, Ji Yeon [Molecular Imaging Program at Stanford, Stafnord University, Richmond (United States)


    Adaptive radiation therapy (ART) provides more conformal dose distribution to the morphologically and physiologically changed tumor volumes during fractionated radiation therapy (RT). To develop an enhanced treatment plan evaluation tool based on multi-modality imaging which incorporates physical and radiobiological parameters, the software system was developed using MATLAB v.7.10.0499 (The Mathworks, Inc., Natick, MA). The application of plan evaluation can help the user choose more biologically optimal treatment plans and potentially predict treatment outcome more accurately. The radiotherapy planning based on the multi-modality images had more accurate results than that of based on only CT images in both physical and radiobiological perspectives.

  3. Heavy ion microprobes: a unique tool for bystander research and other radiobiological applications

    Voss, K. O.; Fournier, C.; Taucher-Scholz, G.


    The risk assessment for low doses of high linear energy transfer (LET) radiation has been challenged by a growing body of experimental evidence showing that non-irradiated bystander cells can receive signals from irradiated cells to elicit a variety of cellular responses. These may be significant for radiation protection but also for radiation therapy using heavy ions. Charged particle microbeams for radiobiological application provide a unique means to address these issues by allowing the precise irradiation of single cells with a counted numbers of ions. Here, we focus specifically on heavy ion microbeam facilities currently in use for biological purposes, describing their technical features and biological results. Typically, ion species up to argon are used for targeted biological irradiation at the vertically collimated microbeam at JAEA (Takasaki, Japan). At the SNAKE microprobe in Munich, mostly oxygen ions have been used in a horizontal focused beam line for cell targeting. At GSI (Darmstadt), a horizontal microprobe with a focused beam for defined targeting using ion species up to uranium is operational. The visualization of DNA damage response proteins relocalizing to defined sites of ion traversal has been accomplished at the three heavy ion microbeam facilities described above and is used to study mechanistic aspects of heavy ion effects. However, bystander studies have constituted the main focus of biological applications. While for cell inactivation and effects on cell cycle progression a response of non-targeted cells has been described at JAEA and GSI, respectively, in part controversial results have been obtained for the induction of DNA damage measured by double-strand formation or at the cytogenetic level. The results emphasize the influence of the cellular environment, and standardization of experimental conditions for cellular studies at different facilities as well as the investigation of bystander effects in tissue will be the aims of future

  4. Etude sur les tendons en materiaux composites et leur application aux ancrages postcontraints

    Chennouf, Adil

    L'objectif general de la presente these est d'evaluer le comportement a l'arrachement et au fluage d'ancrages injectes constitues de tendons en materiaux composites afin d'etablir des recommandations plus appropriees et realistes pour le dimensionnement et la conception. Quatre types de tendons en materiaux composites, deux a base de fibres d'aramide et deux a base de fibres de carbone, ont ete utilises dans l'etude. Les travaux de recherche de cette these ont porte notamment sur: (I) Une caracterisation physique et mecanique des tendons en materiaux composites utilises dans l'etude. (II) Une etude en laboratoire sur les coulis de scellement. La premiere etape de cette etude a concerne le developpement d'un coulis de scellement performant adapte aux tendons en materiaux composites et a differentes situations d'injection. La seconde etape a traite des essais de caracterisations physique et mecanique du coulis de scellement developpe comparativement a trois coulis de scellement usuels d'un meme rapport E/L de 0,4. (III) Une etude sur des modeles reduits d'ancrages injectes. (IV) Une etude sur des modeles d'ancrages a grande echelle. La synthese de ces etudes a permis d'enoncer les principales conclusions suivantes: (1) Les valeurs moyennes des charges de rupture des tendons en materiaux composites ont ete de 1% a 29% superieures a celles specifiees par les manufacturiers. (2) L'etude sur les coulis de scellement a permis le developpement de coulis de ciment repondant aux criteres fixes, soient une grande stabilite, une bonne fluidite, une legere expansion et de bonnes caracteristiques mecaniques. (3) Les tendons en materiaux composites ont montre des contraintes d'adherence maximum superieures a celles des tendons en acier. (4) Le type de fibre, la configuration et le fini de surface des tendons en materiaux composites gouvernent leur resistance a l'adherence. (5) L'introduction de sable et d'autres ajouts comme les fines de silice et la poudre d'aluminium au coulis

  5. Radiobiological rationale and clinical implications of hypo-fractionated radiation therapy; Bases radiobiologiques et applications cliniques de la radiotherapie hypofractionnee

    Ko, E.C.; Forsythe, K.; Buckstein, M.; Kao, J.; Rosenstein, B.S. [Department of Radiation Oncology, Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1236, New York, NY (United States)


    Recent clinical trials of hypo-fractionated radiation treatment have provided critical insights into the safety and efficacy of hypo-fractionation. However, there remains much controversy in the field, both at the level of clinical practice and in our understanding of the underlying radiobiological mechanisms. In this article, we review the clinical literature on hypo-fractionated radiation treatment for breast, prostate, and other malignancies. We highlight several ongoing clinical trials that compare outcomes of a hypo-fractionated approach versus those obtained with a conventional approach. Lastly, we outline some of the preclinical and clinical evidence that argue in favor of differential radiobiological mechanisms underlying hypo-fractionated radiation treatment. Emerging data from the ongoing studies will help to better define and guide the rational use of hypo-fractionation in future years. (authors)

  6. Radiobiological Research in JINR

    Krasavin, E A


    The results of long-term radiobiological and radiation-genetical research in DRRR (Division of Radiobiology) are summarized. The different radiation-induced effects in bacteria, yeasts, mammalian and human cells after irradiation by gamma-rays and heavy charged particles are considered. The important role of DNA repair processes in biological effectiveness of different types of radiation were shown. The data on mutagenic action of such kinds of radiation on pro- and eukaryotic cells were analyzed. On the basis of our data the hypersensitivity of human and mammalian chromosomes after low doses of gamma-rays (10-20 sGy) was revealed. The radiobiological effect of ^{211}At - methylene blue complex on human melanoma cells was studied. The extremely high effectiveness of this complex on melanoma cells was shown.

  7. Automation of the particle dosimetry and the dose application for radiobiological experiments at a vertical proton beam

    Moertel, H; Eyrich, W; Fritsch, M; Distel, L


    A facility with a vertical beam for radiobiological experiments with low-energy protons has been setup at the Tandem accelerator at Erlangen. This energy region is optimal to investigate the biological effects of the linear energy transfer in the Bragg region under physiological conditions. A new automated data acquisition system for dosimetry and monitoring based on a personal computer was developed and optimized for this setup. A specially designed sample holder offers possibilities of cooling or changing of atmosphere during irradiation. First irradiations of biological samples have shown the functionality of the setup.

  8. With the Radiobiology Group


    The Radiobiology Group carries out experiments to study the effect of radiation on living cells. The photo shows the apparatus for growing broad beans which have been irradiated by 250 GeV protons. The roots are immersed in a tank of running water (CERN Weekly Bulletin 26 January 1981 and Annual Report 1980 p. 160). Karen Panman, Marilena Streit-Bianchi, Roger Paris.

  9. Radiobiology with heavy charged particles: a historical review

    Skarsgard, L.D. [Dept. of Medical Biophysics, B.C. Cancer Research Centre and TRIUMF, Vancouver (Canada)


    The presentation will attempt to briefly review some of radiobiological data on the effects of heavy charged particles and to discuss the influence of those studies on the clinical application which followed. (orig./MG)

  10. Dosimetry and radiobiology at the new RA-3 reactor boron neutron capture therapy (BNCT) facility: Application to the treatment of experimental oral cancer

    Pozzi, E. [Research and Production Reactors, National Atomic Energy Commission, Ezeiza Atomic Center (Argentina); Department of Radiobiology, National Atomic Energy Commission, Constituyentes Atomic Center (Argentina)], E-mail:; Nigg, D.W. [Idaho National Laboratory, Idaho Falls (United States); Miller, M.; Thorp, S.I. [Instrumentation and Control Department, National Atomic Energy Commission, Ezeiza Atomic Center (Argentina); Heber, E.M. [Department of Radiobiology, National Atomic Energy Commission, Constituyentes Atomic Center (Argentina); Zarza, L.; Estryk, G. [Research and Production Reactors, National Atomic Energy Commission, Ezeiza Atomic Center (Argentina); Monti Hughes, A.; Molinari, A.J.; Garabalino, M. [Department of Radiobiology, National Atomic Energy Commission, Constituyentes Atomic Center (Argentina); Itoiz, M.E. [Department of Radiobiology, National Atomic Energy Commission, Constituyentes Atomic Center (Argentina); Department of Oral Pathology, Faculty of Dentistry, University of Buenos Aires (Argentina); Aromando, R.F. [Department of Oral Pathology, Faculty of Dentistry, University of Buenos Aires (Argentina); Quintana, J. [Research and Production Reactors, National Atomic Energy Commission, Ezeiza Atomic Center (Argentina); Trivillin, V.A.; Schwint, A.E. [Department of Radiobiology, National Atomic Energy Commission, Constituyentes Atomic Center (Argentina)


    The National Atomic Energy Commission of Argentina (CNEA) constructed a novel thermal neutron source for use in boron neutron capture therapy (BNCT) applications at the RA-3 research reactor facility located in Buenos Aires. The aim of the present study was to perform a dosimetric characterization of the facility and undertake radiobiological studies of BNCT in an experimental model of oral cancer in the hamster cheek pouch. The free-field thermal flux was 7.1x10{sup 9} n cm{sup -2} s{sup -1} and the fast neutron flux was 2.5x10{sup 6} n cm{sup -2} s{sup -1}, indicating a very well-thermalized neutron field with negligible fast neutron dose. For radiobiological studies it was necessary to shield the body of the hamster from the neutron flux while exposing the everted cheek pouch bearing the tumors. To that end we developed a lithium (enriched to 95% in {sup 6}Li) carbonate enclosure. Groups of tumor-bearing hamsters were submitted to BPA-BNCT, GB-10-BNCT, (GB-10+BPA)-BNCT or beam only treatments. Normal (non-cancerized) hamsters were treated similarly to evaluate normal tissue radiotoxicity. The total physical dose delivered to tumor with the BNCT treatments ranged from 6 to 8.5 Gy. Tumor control at 30 days ranged from 73% to 85%, with no normal tissue radiotoxicity. Significant but reversible mucositis in precancerous tissue surrounding tumors was associated to BPA-BNCT. The therapeutic success of different BNCT protocols in treating experimental oral cancer at this novel facility was unequivocally demonstrated.

  11. Dosimetry and radiobiology at the new RA-3 reactor boron neutron capture therapy (BNCT) facility: application to the treatment of experimental oral cancer.

    Pozzi, E; Nigg, D W; Miller, M; Thorp, S I; Heber, E M; Zarza, L; Estryk, G; Monti Hughes, A; Molinari, A J; Garabalino, M; Itoiz, M E; Aromando, R F; Quintana, J; Trivillin, V A; Schwint, A E


    The National Atomic Energy Commission of Argentina (CNEA) constructed a novel thermal neutron source for use in boron neutron capture therapy (BNCT) applications at the RA-3 research reactor facility located in Buenos Aires. The aim of the present study was to perform a dosimetric characterization of the facility and undertake radiobiological studies of BNCT in an experimental model of oral cancer in the hamster cheek pouch. The free-field thermal flux was 7.1 x 10(9) n cm(-2)s(-1) and the fast neutron flux was 2.5 x 10(6) n cm(-2)s(-1), indicating a very well-thermalized neutron field with negligible fast neutron dose. For radiobiological studies it was necessary to shield the body of the hamster from the neutron flux while exposing the everted cheek pouch bearing the tumors. To that end we developed a lithium (enriched to 95% in (6)Li) carbonate enclosure. Groups of tumor-bearing hamsters were submitted to BPA-BNCT, GB-10-BNCT, (GB-10+BPA)-BNCT or beam only treatments. Normal (non-cancerized) hamsters were treated similarly to evaluate normal tissue radiotoxicity. The total physical dose delivered to tumor with the BNCT treatments ranged from 6 to 8.5 Gy. Tumor control at 30 days ranged from 73% to 85%, with no normal tissue radiotoxicity. Significant but reversible mucositis in precancerous tissue surrounding tumors was associated to BPA-BNCT. The therapeutic success of different BNCT protocols in treating experimental oral cancer at this novel facility was unequivocally demonstrated.

  12. Research trends in radiobiology since 40 years. a new approach: the enzymatic repair function of DNA, internal factor in evolution of biological systems under irradiation; Etude des tendances des recherches en radiologie depuis 40 ans. Une nouvelle voie de recherche: la fonction de reparation enzymatique de l'ADN, facteur interne d'evolution des systemes biologiques sous rayonnement

    Mouton, R. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    In the first part of the report, the author attempts to draw an historical scheme of successive research working hypotheses in radiobiology since 1924. Less than a generation ago the effect of radiation exposure were viewed as being direct, immediate, irreparable and unmodifiable. Now it is generally accepted that radiation lesion can also be indirect, delayed, reparable and often modified with appropriate chemical or biochemical treatment. It was however in 1962-1964 that came the decisive breakthrough in radiobiology with the discovery that the cell possesses a natural active self-defense mechanism against whatever stress would affect the integrity of the genetic message contained in the DNA structure itself. The existence of what could be considered as a fourth DNA function i.e. self-repair by enzymatic action under genetic control-brings at least to radiobiology the missing molecular biology basis it needed to get out of its 'phenomenological night' after abandon of the generalization of Lea's theory through lack of experimental evidence. In the second part, which is a prospective one, the author tries to set an enlarged synthesis considering the possible role of DNA repair system not only in cell survival - in presence or absence of dose modifiers or mutagens - but also in the artificial and natural evolution of biological system exposed to sub-lethal doses of radiation. Most recent data from the literature fit well with what must be still considered as a general working hypothesis. Studies dealing with phenotypic and genotypic characters linked with the acquisition of gamma and UV radiation resistance in 'Escherichia coli K12' has been started by the author, in collaboration with O. Tremeau, in order to bring a new experimental contribution in this respect. (author) [French] Dans la premiere partie, l'auteur tente de retracer l'historique des hypotheses successives qui ont jalonne les avances de la radiobiologie depuis 1924

  13. Radiobiology of Radiosurgery for the Central Nervous System

    Antonio Santacroce


    Full Text Available According to Leksell radiosurgery is defined as “the delivery of a single, high dose of irradiation to a small and critically located intracranial volume through the intact skull.” Before its birth in the early 60s and its introduction in clinical therapeutic protocols in late the 80s dose application in radiation therapy of the brain for benign and malignant lesions was based on the administration of cumulative dose into a variable number of fractions. The rationale of dose fractionation is to lessen the risk of injury of normal tissue surrounding the target volume. Radiobiological studies of cell culture lines of malignant tumors and clinical experience with patients treated with conventional fractionated radiotherapy helped establishing this radiobiological principle. Radiosurgery provides a single high dose of radiation which translates into a specific toxic radiobiological response. Radiobiological investigations to study the effect of high dose focused radiation on the central nervous system began in late the 50s. It is well known currently that radiobiological principles applied for dose fractionation are not reproducible when single high dose of ionizing radiation is delivered. A review of the literature about radiobiology of radiosurgery for the central nervous system is presented.

  14. Radiation Protection Research: Radiobiology

    Desaintes, C


    The main objectives of research in the field of radiobiology and epidemiology performed at the Belgian Nuclear Research Centre SCK-CEN are (1) to study cancer mortality in nuclear workers in Belgium; to document the feasibility of retrospective cohort studies in Belgium; (2) to participate in the IARC study; (3) to elucidate the molecular basis of the effects of ionising radiation in the mammalian embryo during the early phases of its development; (4) to assess the genetic risk of maternal exposure to ionizing radiation; (5) to elucidate the cellular mechanisms leading to brain damage after prenatal irradiation; (6) to advise authorities and to provide the general population with adequate information concerning the health risk arising from radiation exposure. Progress and major achievements in these topical areas in 1999 are reported.

  15. Dosimetry for radiobiology experiments at GANIL

    Durantel, Florent; Balanzat, Emmanuel; Cassimi, Amine; Chevalier, François; Ngono-Ravache, Yvette; Madi, Toiammou; Poully, Jean-Christophe; Ramillon, Jean-Marc; Rothard, Hermann; Ropars, Frédéric; Schwob, Lucas; Testard, Isabelle; Saintigny, Yannick


    Mainly encouraged by the increasing application of ion beams for cancer treatment (hadron-therapy) including carbon beams, the use of heavy ion facilities for radiobiology is expanding rapidly today. As an alternative to dedicated centers for treatment and medical research, accelerators like GANIL offer the possibility to undertake such experiments. Since 20 years, CIMAP, reinforced 15 years ago by the biological host laboratory LARIA, has been receiving researchers in radiobiology and assisted them in performing experiments in different fields such as hadron-therapy, space radioprotection and fundamental biological and physico-chemical mechanisms. We present here a short description of the beam line and the on-line equipments that allow the automatic irradiation of up to 24 biological samples at once. We also developed an original on-line beam monitoring procedure for low ion flux (low dose rates) based on the measurement of the K-shell X-rays emitted from a thin iron foil. This detector is calibrated on an absolute scale before each experiment by counting etched tracks on an irradiated CR39 polymer plate. We present the performances and limits of this method and finally give typical fluence (dose) uncertainties for a standard irradiation in radiobiology.

  16. Dosimetry for radiobiology experiments at GANIL

    Durantel, Florent, E-mail: [CIMAP-GANIL, Caen (France); Balanzat, Emmanuel; Cassimi, Amine [CIMAP-GANIL, Caen (France); Chevalier, François [CEA/DSV/LARIA, Caen (France); Ngono-Ravache, Yvette; Madi, Toiammou; Poully, Jean-Christophe; Ramillon, Jean-Marc; Rothard, Hermann; Ropars, Frédéric; Schwob, Lucas [CIMAP-GANIL, Caen (France); Testard, Isabelle [CEA/DSV/CBM/iRTSV, Grenoble (France); Saintigny, Yannick [CEA/DSV/LARIA, Caen (France)


    Mainly encouraged by the increasing application of ion beams for cancer treatment (hadron-therapy) including carbon beams, the use of heavy ion facilities for radiobiology is expanding rapidly today. As an alternative to dedicated centers for treatment and medical research, accelerators like GANIL offer the possibility to undertake such experiments. Since 20 years, CIMAP, reinforced 15 years ago by the biological host laboratory LARIA, has been receiving researchers in radiobiology and assisted them in performing experiments in different fields such as hadron-therapy, space radioprotection and fundamental biological and physico-chemical mechanisms. We present here a short description of the beam line and the on-line equipments that allow the automatic irradiation of up to 24 biological samples at once. We also developed an original on-line beam monitoring procedure for low ion flux (low dose rates) based on the measurement of the K-shell X-rays emitted from a thin iron foil. This detector is calibrated on an absolute scale before each experiment by counting etched tracks on an irradiated CR39 polymer plate. We present the performances and limits of this method and finally give typical fluence (dose) uncertainties for a standard irradiation in radiobiology.

  17. Light ions radiobiological effects on human tumoral cells: measurements modelling and application to hadron-therapy; Mesures et modelisation des effets radiobiologiques des ions legers sur des cellules tumorales humaines: application a l'hadrontherapie

    Jalade, P


    In classical radiotherapy, the characteristics of photons interactions undergo limits for the treatment of radioresistant and not well located tumours. Pioneering treatments of patients at the Lawrence Laboratory at Berkeley has demonstrated two advantages of hadrons beams: the Relative Biologic Effect (the RBE) and the ballistic of the beams. Since 1994, the clinical centre at Chiba, has demonstrated successfully the applicability of the method. A physics group, managed by G. Kraft, at Darmstadt in Germany, has underlined the advantages of carbon beams. An European pool, called ENGIGHT (European Network for LIGHt ion Therapy) has been created in which the French ETOILE project appeared. The purpose of the thesis concerns measurements and models of 'in vitro' human cells survival. In the first part, the nowadays situation in particles interactions, tracks and cells structures and radiobiology is presented here. The second is devoted to the models based on the beam tracks and localization of the physical dose. Discussion of sensitivity to various parameters of the model has been realized with the help of numerical simulations. Finally the predictions of the improved model has been compared to experimental irradiations of human cells with argon and carbon beams of the GANIL machine. Conclusion of such study shows the performance and limits of a local model for predicting the radiobiological efficiency of light ions in hadron-therapy. (author)

  18. Radiobiology and Epidemiology

    Desaintes, C; Holmstock, L


    The main objectives of research in the field of radiobiology and epidemiology performed at the Belgian Nuclear Research Centre SCK-CEN are: (1) to study cancer mortality in nuclear workers in Belgium and to co-ordinate the Belgian contribution to the 'International Collaborative Study of Cancer Risk among Radiation Workers in the Nuclear Industry'; (2) to elucidate the molecular basis of individual susceptibility to ionizing radiation in mammalian embryo during the early phases of its development; (3) to assess the genetic risk of maternal exposure to ionizing radiation; (4) to elucidate the cellular mechanisms leading to brain damage after prenatal irradiation; (5) to monitor the early variations of gene expression induced by ionising radiation and cytokines; (6) to evaluate the use of cytokines and natural substances for improving radiotherapy protocols; (6) to advise authorities and to provide the general population with adequate information concerning the health risk arising from radiation exposure. Progress and major achievements in these topical areas in 2000 are reported.

  19. Radiobiological evaluation of the radiation dose as used in high-precision radiotherapy: effect of prolonged delivery time and applicability of the linear-quadratic model.

    Shibamoto, Yuta; Otsuka, Shinya; Iwata, Hiromitsu; Sugie, Chikao; Ogino, Hiroyuki; Tomita, Natsuo


    Since the dose delivery pattern in high-precision radiotherapy is different from that in conventional radiation, radiobiological assessment of the physical dose used in stereotactic irradiation and intensity-modulated radiotherapy has become necessary. In these treatments, the daily dose is usually given intermittently over a time longer than that used in conventional radiotherapy. During prolonged radiation delivery, sublethal damage repair takes place, leading to the decreased effect of radiation. This phenomenon is almost universarily observed in vitro. In in vivo tumors, however, this decrease in effect can be counterbalanced by rapid reoxygenation, which has been demonstrated in a laboratory study. Studies on reoxygenation in human tumors are warranted to better evaluate the influence of prolonged radiation delivery. Another issue related to radiosurgery and hypofractionated stereotactic radiotherapy is the mathematical model for dose evaluation and conversion. Many clinicians use the linear-quadratic (LQ) model and biologically effective dose (BED) to estimate the effects of various radiation schedules, but it has been suggested that the LQ model is not applicable to high doses per fraction. Recent experimental studies verified the inadequacy of the LQ model in converting hypofractionated doses into single doses. The LQ model overestimates the effect of high fractional doses of radiation. BED is particularly incorrect when it is used for tumor responses in vivo, since it does not take reoxygenation into account. For normal tissue responses, improved models have been proposed, but, for in vivo tumor responses, the currently available models are not satisfactory, and better ones should be proposed in future studies.

  20. The radiobiology of hypofractionation.

    Nahum, Alan E


    If the α/β ratio is high (e.g. 10 Gy) for tumour clonogen killing, but low (e.g. 3 Gy) for late normal tissue complications, then delivering external beam radiotherapy in a large number (20-30) of small (≈2 Gy) dose fractions should yield the highest 'therapeutic ratio'; this is demonstrated via the linear-quadratic model of cell killing. However, this 'conventional wisdom' is increasingly being challenged, partly by the success of stereotactic body radiotherapy (SBRT) or stereotactic ablative radiotherapy (SABR) extreme hypofractionation regimens of three to five large fractions for early stage non-small cell lung cancer and partly by indications that for certain tumours (prostate, breast) the α/β ratio may be of the same order or even lower than that characterising late complications. It is shown how highly conformal dose delivery combined with quasi-parallel normal tissue behaviour (n close to 1) enables 'safe' hypofractionation; this can be predicted by the (α/β)eff concept for normal tissues. Recent analyses of the clinical outcomes of non-small cell lung cancer radiotherapy covering 'conventional' hyper- to extreme hypofractionation (stereotactic ablative radiotherapy) regimens are consistent with linear-quadratic radiobiology, even at the largest fraction sizes, despite there being theoretical reasons to expect 'LQ violation' above a certain dose. Impairment of re-oxygenation between fractions and the very high (α/β) for hypoxic cells can complicate the picture regarding the analysis of clinical outcomes; it has also been suggested that vascular damage may play a role for very large dose fractions. Finally, the link between high values of (α/β)eff and normal-tissue sparing for quasi-parallel normal tissues, thereby favouring hypofractionation, may be particularly important for proton therapy, but more generally, improved conformality, achieved by whatever technique, can be translated into individualisation of both prescription dose and fraction

  1. Folds and Etudes

    Bean, Robert


    In this article, the author talks about "Folds" and "Etudes" which are images derived from anonymous typing exercises that he found in a used copy of "Touch Typing Made Simple". "Etudes" refers to the musical tradition of studies for a solo instrument, which is a typewriter. Typing exercises are repetitive attempts to type words and phrases…

  2. Microirradiation techniques in radiobiological research

    Guido A Drexler; Miguel J Ruiz-Gómez


    The aim of this work is to review the uses of laser microirradiation and ion microbeam techniques within the scope of radiobiological research. Laser microirradiation techniques can be used for many different purposes. In a specific condition, through the use of pulsed lasers, cell lysis can be produced for subsequent separation of different analytes. Microsurgery allows for the identification and isolation of tissue sections, single cells and subcellular components, using different types of lasers. The generation of different types of DNA damage, via this type of microirradiation, allows for the investigation of DNA dynamics. Ion microbeams are important tools in radiobiological research. There are only a limited number of facilities worldwide where radiobiological experiments can be performed. In the beginning, research was mostly focused on the bystander effect. Nowadays, with more sophisticated molecular and cellular biological techniques, ion microirradiation is used to unravel molecular processes in the field of radiobiology. These include DNA repair protein kinetics or chromatin modifications at the site of DNA damage. With the increasing relevance of charged particles in tumour therapy and new concepts on how to generate them, ion microbeam facilities are able to address unresolved questions concerning particle tumour therapy.

  3. Radiotherapy treatment planning linear-quadratic radiobiology

    Chapman, J Donald


    Understand Quantitative Radiobiology from a Radiation Biophysics PerspectiveIn the field of radiobiology, the linear-quadratic (LQ) equation has become the standard for defining radiation-induced cell killing. Radiotherapy Treatment Planning: Linear-Quadratic Radiobiology describes tumor cell inactivation from a radiation physics perspective and offers appropriate LQ parameters for modeling tumor and normal tissue responses.Explore the Latest Cell Killing Numbers for Defining Iso-Effective Cancer TreatmentsThe book compil

  4. 77 FR 68155 - The Armed Forces Radiobiology Research Institute TRIGA Reactor: Facility Operating License No. R-84


    ... COMMISSION The Armed Forces Radiobiology Research Institute TRIGA Reactor: Facility Operating License No. R... Operating License No. R-84 (Application), which currently authorizes the Armed Forces Radiobiology Research... the renewal of Facility Operating License No. R-84, which currently authorizes the licensee to...




    For the past several years, the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory (USA) has provided ions of iron, silicon and gold, at energies from 600 MeV/nucleon to 10 GeV/nucleon, for the US National Aeronautics and Space Administration (NASA) radiobiology research program. NASA has recently funded the construction of a new dedicated ion facility, the Booster Applications Facility (BAF). The Booster synchrotron will supply ion beams ranging from protons to gold, in an energy range from 40--3,000 MeV/nucleon with maximum beam intensities of 10{sup 10} to 10{sup 11} ions per pulse. The BAF Project is described and the future AGS and BAF operation plans are presented.

  6. [Systemic approach to radiobiological studies].

    Bulanova, K Ia; Lobanok, L M


    The principles of information theory were applied for analysis of radiobiological effects. The perception of ionizing radiations as a signal enables living organism to discern their benefits or harm, to react to absolute and relatively small deviations, to keep the logic and chronicle of events, to use the former experience for reacting in presence, to forecast consequences. The systemic analysis of organism's response to ionizing radiations allows explaining the peculiarities of effects of different absorbed doses, hormesis, apoptosis, remote consequences and other post-radiation effects.

  7. Radiobiology of human cancer radiotherapy

    Andrews, J.R.


    The author has systematically collected and collated the scientific literature correlating the basic and clinical sciences in this field in order to produce a definitive treatise. The book thoroughly reviews the biology and biochemistry relevant to radiobiology and describes the critical locus for the extinction of cell reproductive capacity. Extensive coverage is given to oxygen effect, hyperthermia, high linear energy transfer, cell populations, and similar topics. Separate sections cover time, dose, and fractionation; radiation hematology; cancer chemotherapy; and cancer immunology. The book also contains invaluable discussions of techniques for optimizing radiotherapy alone and in combination with other therapies.

  8. Literature study of the radiobiological parameters of Caesium-137 required for evaluating internal irradiation doses as a function of age; Etude bibliographique des parametres radiobiologiques du cesium-137 necessaires a l'evaluation des doses d'irradiation interne en fonction de l'age

    Garnier, A. [Commissariat a l' Energie Atomique, 92 - Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires


    This document reassembles information published in scientific literature on radiobiological parameters of Cs-137, necessary for the estimate of the internal irradiation dose of man according to his age (during growth). The data are completed by a commented review of the mathematical models, proposed in order to value the irradiation doses from ingested cesium and the biological parameters. (author) [French] Ce document rassemble les informations publiees dans la litterature scientifique, concernant les parametres radiobiologiqueo du cesium-137, necessaires a l'evaluation des doses d'irradiation interne de l'homme en fonction de l'age. Ces donnees sont completees par une revue commentee des modeles mathematiques proposes en vue de l'evaluation des doses d'irradiation a partir des quantites de cesium ingerees et des parametres biologiques. (auteur)

  9. New challenges in high-energy particle radiobiology.

    Durante, M


    Densely ionizing radiation has always been a main topic in radiobiology. In fact, α-particles and neutrons are sources of radiation exposure for the general population and workers in nuclear power plants. More recently, high-energy protons and heavy ions attracted a large interest for two applications: hadrontherapy in oncology and space radiation protection in manned space missions. For many years, studies concentrated on measurements of the relative biological effectiveness (RBE) of the energetic particles for different end points, especially cell killing (for radiotherapy) and carcinogenesis (for late effects). Although more recently, it has been shown that densely ionizing radiation elicits signalling pathways quite distinct from those involved in the cell and tissue response to photons. The response of the microenvironment to charged particles is therefore under scrutiny, and both the damage in the target and non-target tissues are relevant. The role of individual susceptibility in therapy and risk is obviously a major topic in radiation research in general, and for ion radiobiology as well. Particle radiobiology is therefore now entering into a new phase, where beyond RBE, the tissue response is considered. These results may open new applications for both cancer therapy and protection in deep space.

  10. New challenges in high-energy particle radiobiology


    Densely ionizing radiation has always been a main topic in radiobiology. In fact, α-particles and neutrons are sources of radiation exposure for the general population and workers in nuclear power plants. More recently, high-energy protons and heavy ions attracted a large interest for two applications: hadrontherapy in oncology and space radiation protection in manned space missions. For many years, studies concentrated on measurements of the relative biological effectiveness (RBE) of the energetic particles for different end points, especially cell killing (for radiotherapy) and carcinogenesis (for late effects). Although more recently, it has been shown that densely ionizing radiation elicits signalling pathways quite distinct from those involved in the cell and tissue response to photons. The response of the microenvironment to charged particles is therefore under scrutiny, and both the damage in the target and non-target tissues are relevant. The role of individual susceptibility in therapy and risk is obviously a major topic in radiation research in general, and for ion radiobiology as well. Particle radiobiology is therefore now entering into a new phase, where beyond RBE, the tissue response is considered. These results may open new applications for both cancer therapy and protection in deep space. PMID:24198199

  11. Radiobiological study of the radioprotective activity of a natural Iranian compound, ''Shir-Khecht''; Etude radiobiologique de l'activite radioprotectrice d'un compose naturel Iranien: le ''Shir-Khecht''

    Rouhanizadeh, N. [Commissariat a l' Energie Atomique, 92 - Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires


    After reviewing the primary mechanisms of the action of ionizing radiation, the possible mechanisms of the action of radioprotective substances, the various chemical structures having a protective effect and the methods for studying chemical radioprotection, the author presents the results he has obtained with natural Iranian product: ''Shir-Khecht''. Tests with this product at lethal and sublethal doses have been carried out on the rat using various means of introduction. The effect of radiation, both with and without protection, has been studied using histological and biochemical methods. The product examined has, in effect, a protective action; it is, furthermore, non-toxic and active when taken orally. (author) [French] Apres avoir rappele les mecanismes primaires de l'action des rayonnements ionisants, les mecanismes possibles de l'action des substances radioprotectrices, les diverses structures chimiques possedant un effet protecteur et les methodes d'etude de la radioprotection chimique, l'auteur presente les resultats qu'il a obtenus en utilisant un compose naturel iranien: le ''Shir-Khecht''. Des essais de ce produit, chez le rat, par diverses voies d'introduction, a dose letale et subletale ont ete effectues. L'effet des radiations, avec et sans protection, a ete etudie a l'aide de methodes histologiques et biochimiques. Le compose essaye possede un pouvoir protecteur; il est, de plus, non toxique et actif par voie orale. (auteur)

  12. Histological data concerning the pig (sus scrofa) for use in radiobiology. I. Normal histology of certain systems. 2. Injuries caused by total {gamma} irradiation; Donnees histologiques sur le porc (sus scrofa), utilisables en radiobiologie. 1. histologie normale de certains appareils. 2. etude des lesions consecutives a une irradiation {gamma} totale

    Guenet, J.L.; Vaiman, M.; Nizza, P. [Commissariat a L' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires


    The domestic pig lately become a laboratory whose anatomical and physiological characteristics appear to be appreciated for certain radiological studies. In this report the authors describe research which they have carried out (in particular in the field of histology) on domestic pigs of different species with a view to compiling a record which might be of help to future workers in this field. The second part of their work deals with anatomical and histological injuries caused by total exposure to gamma radiation from cobalt 60 at doses of around 285 rads. (authors) [French] Le porc domestique est devenu depuis peu un animal de laboratoire, dont les caracteristiques anatomiques et physiologiques paraissent fort appreciees pour certaines etudes de radiobiologie. Dans ce rapport les auteurs font part des recherches qu'ils ont effectuees (notamment dans le domaine de l'histologie) sur des porcs domestiques de differentes races, de maniere a constituer un document capable de venir en aide aux utilisateurs eventuels. La deuxieme partie de leur travail traite de lesions anatomiques et histologiques, consecutives a des expositions totales aux rayonnements gamma du cobalt 60 a des doses voisines de 285 rads. (auteurs)

  13. Contributions a l'etude et a l'application industrielle de la machine asynchrone

    Ouhrouche, Mohand-Ameziane

    The work presented in this thesis, done in the Electrical Drives Laboratory of Electrical and Computer Engineering Department, deals with the industrial applications of a three-phase induction machine (electrical drives and electricity generation). This thesis, characterized by its multidisciplinary content, has two major parts. The first one deals with the on-line and off-line parametric identification of the induction machine model necessary to achieve accurate vector control strategy. The second part, which is a resume of a research work sponsored by Hydro-Quebec, deals with the application of an induction machine in Asynchronous Non Utility Generators units (ANUG). As it is shown in the following, major scientific contributions are made in both two parts. In the first part of our research work, we propose a new speed sensorless vector control strategy for an induction machine, which is adaptive to the rotor resistance variations. The proposed control strategy is based on the Extended Kalman Filter approach and a decoupling controller which takes into account the rotor resistance variations. The consideration of coupled electrical and mechanical modes leads to a fifth order nonlinear model of the induction machine. The load torque is taken as a function of the rotor angular speed. The Extended Kalman Filter, based on the process's nonlinear (bilinear) model, estimate simultaneously the rotor resistance, angular speed and the flux vector from the startup to the steady state equilibrium point. The machine-converter-control system is implemented in MATLAB/SIMULINK environment and the obtained results confirm the robustness of the proposed scheme. As in the electrical drives erea, the induction machine is now widely used by small to medium power Non Utility Generator units (NUG) to produce electricity. In Quebec, these NUGs units are integrated into the Hydro-Quebec 25 kV distribution system via transformer which exhibit nonlinear characteristics. We have shown by

  14. Etude de l'isolation hybride en vue de son application dans les transformateurs de puissance

    Kassi, Koutoua Simon

    For nearly a century the conventional insulation (oil / cellulose complex) was the type of insulation used in the power transformers and most electrical power equipments. But the cellulose paper, the solid part of this insulation has many weaknesses. Indeed, the aging of cellulose paper in power transformers is accelerated by moisture, oxygen, metal catalysts, temperature, etc.). The risk of failures is thereby increased. Another major weakness of cellulose paper is its inability to protect the electrical transformer windings against the harmful effects of corrosive sulfur. Given all the weaknesses of cellulose paper, several studies have been conducted to evaluate the performance of aramid paper, which has better thermal properties. The aramid paper is currently used as high temperature insulation, combined with high fire point oils (synthetic and vegetable oils), mainly in electric traction transformers. The hybrid solid insulation is associated with mineral oil or with high fire point oils; it finds application in transformers of fixed and mobile substations. Manufacturing technology is controlled by manufacturers but operators of electrical networks do not have baseline data (standards) as diagnostic tools, allowing them to monitor the health/condition of the isolation in this new type of transformer. The overall objective of this research was to study the hybrid insulation and to demonstrate its potential use in power transformers. This overall objective has been subdivided into three specific objectives, namely: (i) improving the diagnostic of the condition of solid hybrid insulation and conventional solid insulation; (ii) diagnosing the condition of oils sampled from hybrid, high temperature and conventional insulation and finally (iii) investigating the ability of aramid paper and cellulose paper to protect the copper (electrical windings) against harmful effects of corrosive sulfur. In order to achieve these objectives, thermal accelerated aging were

  15. X-spectrographic method for plutonium detection. Application to contamination measurements in humans; Etude d'une methode de detection du plutonium par spectrographie X. Application a la mesure des contaminations sur l'homme

    Michel Trouble [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    After reviewing the radio-toxicology of plutonium 239 and conventional detection methods using its {alpha}-radiation, the author considers the measurement of the X emission spectrum of plutonium 239 using a proportional counter filled with argon under pressure. This preliminary work leads to the third part of this research involving the detailed study of the possibilities of applying thin alkali halide crystal scintillators to the detection of soft plutonium X-rays; there follows a systematic study of all the parameters liable to render the detection as sensitive as possible: movement due to the photomultiplier itself and its accessory electronic equipment, nature and size of the crystal scintillator as well as its mode of preparation, shielding against external parasitic radiation. Examples of some applications to the measurement of contamination in humans give an idea of the sensitivity of this method. (author) [French] Apres un apercu de la radiotoxicologie du plutonium 239 et des methodes classiques de detection par son rayonnement {alpha}, on etudie le spectre d'emission X du plutonium 239 avec un compteur proportionnel rempli avec de l'argon sous pression. Ce travail preliminaire permet d'aborder la troisieme partie de cette etude dans laquelle nous examinons d'une fagon approfondie les possibilites d'application des cristaux scintillateurs minces d'halogenure alcalin a la detection du rayonnement X mou du plutonium; suit une etude systematique de tous les parametres susceptibles de rendre la detection aussi sensible que possible: mouvement propre du photomultiplicateur et de l'electronique associee, nature et dimensions du cristal scintillateur ainsi que son mode de fabrication, blindage contre les rayonnements parasites exterieurs. Quelques applications a la mesure des contaminations sur l'homme permettent d'apprecier la sensibilite de cette methode. (auteur)

  16. Introduction to radiobiology of targeted radionuclide therapy

    Jean-Pierre ePOUGET


    Full Text Available During the last decades, new radionuclide-based targeted therapies have emerged as efficient tools for cancer treatment. Targeted radionuclide therapies (TRT are based on a multidisciplinary approach that involves the cooperation of specialists in several research fields. Among them, radiobiologists investigate the biological effects of ionizing radiation, specifically the molecular and cellular mechanisms involved in the radiation response. Most of the knowledge about radiation effects concerns external beam radiation therapy (EBRT and radiobiology has then strongly contributed to the development of this therapeutic approach. Similarly, radiobiology and dosimetry are also assumed to be ways for improving TRT, in particular in the therapy of solid tumors which are radioresistant. However, extrapolation of EBRT radiobiology to TRT is not straightforward. Indeed, the specific physical characteristics of TRT (heterogeneous and mixed irradiation, protracted exposure and low absorbed dose rate differ from those of conventional EBRT (homogeneous irradiation, short exposure and high absorbed dose rate, and consequently the response of irradiated tissues might be different. Therefore, specific TRT radiobiology needs to be explored. Determining dose-effect correlation is also a prerequisite for rigorous preclinical radiobiology studies because dosimetry provides the necessary referential to all TRT situations. It is required too for developing patient-tailored TRT in the clinic in order to estimate the best dose for tumor control, while protecting the healthy tissues, thereby improving therapeutic efficacy. Finally, it will allow to determine the relative contribution of targeted effects (assumed to be dose-related and non-targeted effects (assumed to be non-dose-related of ionizing radiation. However, conversely to EBRT where it is routinely used, dosimetry is still challenging in TRT. Therefore, it constitutes with radiobiology, one of the main

  17. Radiobiological compensation: A case study of uterine cervix cancer with concurrent chemotherapy

    Herrera, Higmar; Yañez, Elvia; López, Jesús


    The case of a patient diagnosed with uterine cervix cancer is presented as an example of the clinical application of the radiobiological compensation method implemented at Centro Estatal de Cancerología de Durango. Radiotherapy treatment was initially modified to compensate for the chemotherapy component and, as medical complications arose during treatment delivery resulting in an 18 days gap, new compensation followed. All physical and radiobiological assumptions to calculate the Biologically Effective Dose in the external beam and brachytherapy parts of the treatment are presented. Good local control of the tumor was achieved, the theoretical tolerance limits for the organs at risk were not surpassed and the patient manifested no extensive morbidity.

  18. Radiobiological compensation: A case study of uterine cervix cancer with concurrent chemotherapy

    Herrera, Higmar; Yanez, Elvia; Lopez, Jesus [Centro Estatal de Cancerologia de Durango, Victoria de Durango, Durango (Mexico); ISSSTE General Hospital Dr. Santiago Ramon y Cajal, Victoria de Durango, Durango (Mexico)


    The case of a patient diagnosed with uterine cervix cancer is presented as an example of the clinical application of the radiobiological compensation method implemented at Centro Estatal de Cancerologia de Durango. Radiotherapy treatment was initially modified to compensate for the chemotherapy component and, as medical complications arose during treatment delivery resulting in an 18 days gap, new compensation followed. All physical and radiobiological assumptions to calculate the Biologically Effective Dose in the external beam and brachytherapy parts of the treatment are presented. Good local control of the tumor was achieved, the theoretical tolerance limits for the organs at risk were not surpassed and the patient manifested no extensive morbidity.

  19. In vivo measurements of blood-brain barrier permeability using micro-dialysis: radiobiological application; Etude in vivo des effets de l'irradiation gamma sur la permeabilite de la barriere hemato-encephalique

    Agin, A.; Diserbo, M.; Mauris, J.; Martin, C


    The effects of total-body irradiation on the permeability of striatal blood-brain barrier (BBB) to [{sup 3}H] amino-isobutyric acid (AIBA) and [{sup 14}C] sucrose were investigated. Six weeks, three and five months after gamma exposure at the dose of 4.5 Gy, no modification of the transport of AIB or of the diffusion of sucrose from blood to brain was observed. (authors)

  20. Heavy ion radiobiology for hadrontherapy and space radiation protection.

    Durante, Marco


    Research in the field of biological effects of heavy charged particles is needed for both heavy-ion therapy (hadrontherapy) and protection from the exposure to galactic cosmic radiation in long-term manned space missions. Although the exposure conditions (e.g. high- vs. low-dose rate) and relevant endpoints (e.g. cell killing vs. neoplastic transformation) are different in the two fields, it is clear that a substantial overlap exists in several research topics. Three such topics are discussed in this short review: individual radiosensitivity, mixed radiation fields, and late stochastic effects of heavy ions. In addition, researchers involved either in experimental studies on space radiation protection or heavy-ion therapy will basically use the same accelerator facilities. It seems to be important that novel accelerator facilities planned (or under construction) for heavy-ion therapy reserve a substantial amount of beamtime to basic studies of heavy-ion radiobiology and its applications in space radiation research.

  1. Physics and radiobiology of nuclear medicine

    Saha, Gopal B


    From a distinguished author comes this new edition for technologists, practitioners, residents, and students in radiology and nuclear medicine. Encompassing major topics in nuclear medicine from the basic physics of radioactive decay to instrumentation and radiobiology, it is an ideal review for Board and Registry examinations. The material is well organized and written with clarity. The book is supplemented with tables and illustrations throughout. It provides a quick reference book that is concise but comprehensive, and offers a complete discussion of topics for the nuclear medicine and radi

  2. Radiobiological studies using gamma and x rays.

    Potter, Charles Augustus; Longley, Susan W.; Scott, Bobby R.; Lin, Yong; Wilder, Julie; Hutt, Julie A.; Padilla, Mabel T.; Gott, Katherine M.


    There are approximately 500 self-shielded research irradiators used in various facilities throughout the U.S. These facilities use radioactive sources containing either 137Cs or 60Co for a variety of biological investigations. A report from the National Academy of Sciences[1] described the issues with security of particular radiation sources and the desire for their replacement. The participants in this effort prepared two peer-reviewed publications to document the results of radiobiological studies performed using photons from 320-kV x rays and 137Cs on cell cultures and mice. The effectiveness of X rays was shown to vary with cell type.

  3. Etude de nano-transistors à faible pente sous le seuil pour des applications très basse consommation

    Villalon, Anthony


    Band to band tunneling field effect transistor (TFET) is a PIN-gated architecture able to reach sub 60mV/dec subthreshold slopes at room temperature, which is an advantage over MOSFET in low power applications. The objective of this thesis is to study and characterize TFETs fabricated in CEA-LETI using MOSFET SOI technology. The first generation of devices is realized on planar FDSOI technology, and studies the impact of source/channel heterojunction, channel thickness and annealing temperatu...

  4. Elaboration du Ge mesoporeux et etude de ses proprietes physico-chimiques en vue d'applications photovoltaiques

    Tutashkonko, Sergii

    Le sujet de cette these porte sur l'elaboration du nouveau nanomateriau par la gravure electrochimique bipolaire (BEE) --- le Ge mesoporeux et sur l'analyse de ses proprietes physico-chimiques en vue de son utilisation dans des applications photovoltaiques. La formation du Ge mesoporeux par gravure electrochimique a ete precedemment rapportee dans la litterature. Cependant, le verrou technologique important des procedes de fabrication existants consistait a obtenir des couches epaisses (superieure a 500 nm) du Ge mesoporeux a la morphologie parfaitement controlee. En effet, la caracterisation physico-chimique des couches minces est beaucoup plus compliquee et le nombre de leurs applications possibles est fortement limite. Nous avons developpe un modele electrochimique qui decrit les mecanismes principaux de formation des pores ce qui nous a permis de realiser des structures epaisses du Ge mesoporeux (jusqu'au 10 mum) ayant la porosite ajustable dans une large gamme de 15% a 60%. En plus, la formation des nanostructures poreuses aux morphologies variables et bien controlees est desormais devenue possible. Enfin, la maitrise de tous ces parametres a ouvert la voie extremement prometteuse vers la realisation des structures poreuses a multi-couches a base de Ge pour des nombreuses applications innovantes et multidisciplinaires grace a la flexibilite technologique actuelle atteinte. En particulier, dans le cadre de cette these, les couches du Ge mesoporeux ont ete optimisees dans le but de realiser le procede de transfert de couches minces d'une cellule solaire a triple jonctions via une couche sacrificielle en Ge poreux. Mots-cles : Germanium meso-poreux, Gravure electrochimique bipolaire, Electrochimie des semi-conducteurs, Report des couches minces, Cellule photovoltaique

  5. Physics and radiobiology of nuclear medicine

    Saha, Gopal B


    The Fourth Edition of Dr. Gopal B. Saha’s Physics and Radiobiology of Nuclear Medicine was prompted by the need to provide up-to-date information to keep pace with the perpetual growth and improvement in the instrumentation and techniques employed in nuclear medicine since the last edition published in 2006. Like previous editions, the book is intended for radiology and nuclear medicine residents to prepare for the American Board of Nuclear Medicine, American Board of Radiology, and American Board of Science in Nuclear Medicine examinations, all of which require a strong physics background. Additionally, the book will serve as a textbook on nuclear medicine physics for nuclear medicine technologists taking the Nuclear Medicine Technology Certification Board examination.

  6. Fourier transform infrared microspectroscopy and multivariate methods for radiobiological dosimetry.

    Meade, A D; Clarke, C; Byrne, H J; Lyng, F M


    The scientific literature contains an ever-growing number of reports of applications of vibrational spectroscopy as a multivariate non-invasive tool for analysis of biological effects at the molecular level. Recently, Fourier transform infrared microspectroscopy (FTIRM) has been demonstrated to be sensitive to molecular events occurring in cells and tissue after exposure to ionizing radiation. In this work the application of FTIRM in the examination of dose-dependent molecular effects occurring in skin cells after exposure to ionizing radiation with the use of partial least-squares regression (PLSR) and generalized regression neural networks (GRNN) was studied. The methodology is shown to be sensitive to molecular events occurring with radiation dose and time after exposure. The variation in molecular species with dose and time after irradiation is shown to be non-linear by virtue of the higher modeling efficiency yielded from the non-linear algorithms. Dose prediction efficiencies of approximately +/-10 mGy were achieved at 96 h after irradiation, highlighting the potential applications of the methodology in radiobiological dosimetry.

  7. Biophysical and biomathematical adventures in radiobiology

    Scott, B.R.


    Highlights of my biophysical and biomathematical adventures in radiobiology is presented. Early adventures involved developing state-vector models'' for specific harmful effects (cell killing, life shortening) of exposure to radiation. More recent adventures led to developing hazard-function models'' for predicting biological effects (e.g., cell killing, mutations, tumor induction) of combined exposure to different toxicants. Hazard-function models were also developed for predicting harm to man from exposure to large radiation doses. Major conclusions derived from the modeling adventures are as follows: (1) synergistic effects of different genotoxic agents should not occur at low doses; (2) for exposure of the lung or bone marrow to large doses of photon radiation, low rates of exposure should be better tolerated than high rates; and (3) for some types of radiation (e.g., alpha particles and fission neutrons), moderate doses delivered at a low rate may be more harmful than the same dose given at a high rate. 53 refs., 7 figs.

  8. Amchitka Radiobiological Program. Final report, July 1970-December 1979

    Sibley, T.H.; Tornberg, L.D.


    The Amchitka Radiobiological Program, to collect biological and environmental samples for radiological analyses, began in 1970 and continued through 1979. The principal objective was to determine the extent of radionuclide contamination from worldwide atmospheric fallout and from the detonation of three underground nuclear tests on Amchitka. Leakage of radionuclides from the underground test sites would be suspected if the amount of contamination was significantly greater than could be attributed to worldwide fallout or if an unexpected assemblage of radionuclides was detected. No radionuclides from the underground sites were detected, except for tritium from the Long Shot test (1965) which produced increased tritium concentrations in surface water and freshwater plants near the test site. This final report compiles all previous data into one report and considers the temporal trends in these data. Two naturally occurring radionuclides, /sup 40/K and /sup 7/Be, were the most abundantly occurring radionuclides in most samples; in lichen samples either /sup 137/Cs or /sup 144/Ce had the highest activity. All samples were below applicable Radiation Protection Guides and by 1979 most samples were near or below the statistical detection limits. Increased concentrations of short-lived fallout radionuclides following the Chinese atmospheric tests were found in freshwater and seawater samples and in most indicator organisms.

  9. The application of radioactive isotopes to the study of motion of silt and pebbles in the rivers and in the sea; Application des isotopes radioactifs a l'etude des mouvements des sediments et des galets dans les cours d'eau et en mer

    Hours, R. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires; Jaffry, P. [Electricite de France (EDF), 78 - Chatou (France). Lab. National d' Hydraulique


    The application of radioactive tracers to the study of sediments drift has received considerable attention since 1954 in various countries. A comparative review is made of a number of techniques of labelling, immersing and detecting silts, sands, and pebbles. The influence of the burying of the active material is emphasized. The different experiments which have been so far carried out are described. (author) [French] L'application des traceurs radioactifs a l'etude des deplacements de sediments a fait depuis 1954 l'objet de travaux nombreux dans divers pays. On passe en revue et on compare differentes techniques de marquage, d'immersion et de detection des vases, sables et galets; on insiste sur l'influence de l'enfouissement du materiau actif. On decrit les differentes experiences effectuees jusqu'a ce jour. (auteur)

  10. Criticality studies; Etudes de criticite

    Breton, D.; Lecorche, P.; Clouet d' Orval, Ch. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    Criticality studies made at the Commissariat a l'Energie atomique deal on the one hand with experiments on plutonium and uranium solutions, on the other hand with theoretical work on the development and use of computation, methods for the resolution of problems concerning the nuclear safety of chemical and metallurgical plants. I - Since 1958 the experimental studies have dealt with homogeneous media constituted by a fissile salt dissolved in light water. Developed using the reactor Proserpine, the experiments have been carried on at Saclay on the Alecto assemblies where solutions of plutonium or of 90 p.100 - enriched uranium can be made critical. The results already obtained relate to critical masses of cylindrical tanks of diameters from 20 to 50 cm. reflected in several ways (water, concrete, etc. . ) at concentrations up to 100 g/liter. Physical measurements (spectra, reactor noises) and interaction measurements complete the results. Other experiments relating to plutonium solutions were begun in 1963, at the Valduc Center. They deal with the study of critical masses of annular vessels of external diameter 50 cm and internal diameter varying from 10 to 30 cm. These vessels can be water reflected internally, externally, or both. Two of these vessels have been studied in interaction for various geometries. Slabs of various thicknesses were also studied. II - The studies thus undertaken allowed the development of methods of computation which have been tested on several experiments. Particular use has been made of the possibilities of calculations based on transport theory and on Monte Carlo methods. All these theoretical studies are applied to the design and control of industrial plants from the point of view of safety. (authors) [French] Les etudes de criticite effectuees au CEA comportent d'une part des experiences sur des solutions de plutonium et d'uranium enrichi, d'autre part des travaux theoriques portant sur la mise au point et l

  11. National Radiobiology Archives Distributed Access user's manual

    Watson, C.; Smith, S. (Pacific Northwest Lab., Richland, WA (United States)); Prather, J. (Linfield Coll., McMinnville, OR (United States))


    This User's Manual describes installation and use of the National Radiobiology Archives (NRA) Distributed Access package. The package consists of a distributed subset of information representative of the NRA databases and database access software which provide an introduction to the scope and style of the NRA Information Systems.

  12. Mathematical study of chemical kinetics schemes. Application to air pollution models; Etude mathematique de schemas de cinetique chimique. Application a des modeles de pollution atmospherique

    Billette, E.


    Complex chemical kinetics modelling is relevant in numerous fields related to the petroleum industry, for instance engine combustion, petrochemistry and atmospheric pollution. Many numerical difficulties are encountered in the computation of these models, mainly due to the large size, the non-linearity and the stiffness of the associated ordinary differential systems. We first studied systems that have an asymptotic behaviour which may be derived from an algebraic analysis. Then we reviewed different methods that make possible the reduction of size and stiffness for chemical kinetics-related differential systems, and suggest possible improvements for some of those methods. We also studied their application to atmospheric chemistry models. Finally, we started to extend those reduction methods to partial differential systems that include, in addition to chemical kinetics, other phenomena such as species emission, advection or diffusion. (author) 44 refs.

  13. Design study of the ESS-Bilbao 50 MeV proton beam line for radiobiological studies

    Huerta-Parajon, M.; Martinez-Ballarin, R.; Abad, E.


    The ESS-Bilbao proton accelerator facility has been designed fulfilling the European Spallation Source (ESS) specifications to serve as the Spanish contribution to the ESS construction. Furthermore, several applications of the ESS-Bilbao proton beam are being considered in order to contribute to the knowledge in the field of radiobiology, materials and aerospace components. Understanding of the interaction of radiation with biological systems is of vital importance as it affects important applications such as cancer treatment with ion beam therapy among others. ESS-Bilbao plans to house a facility exclusively dedicated to radiobiological experiments with protons up to 50 MeV. Beam line design, optimisation and initial calculations of flux densities and absorbed doses were undertaken using the Monte Carlo simulation package FLUKA. A proton beam with a flux density of about 106 protons/cm2 s reaches the water sample with a flat lateral distribution of the dose. The absorbed dose at the pristine Bragg peak calculated with FLUKA is 2.4 ± 0.1 Gy in 1 min of irradiation time. This value agrees with the clinically meaningful dose rates, i.e. around 2 Gy/min, used in hadrontherapy. Optimisation and validation studies in the ESS-Bilbao line for radiobiological experiments are detailed in this article.

  14. Design study of the ESS-Bilbao 50 MeV proton beam line for radiobiological studies

    Huerta-Parajon, M., E-mail:; Martinez-Ballarin, R., E-mail:; Abad, E., E-mail:


    The ESS-Bilbao proton accelerator facility has been designed fulfilling the European Spallation Source (ESS) specifications to serve as the Spanish contribution to the ESS construction. Furthermore, several applications of the ESS-Bilbao proton beam are being considered in order to contribute to the knowledge in the field of radiobiology, materials and aerospace components. Understanding of the interaction of radiation with biological systems is of vital importance as it affects important applications such as cancer treatment with ion beam therapy among others. ESS-Bilbao plans to house a facility exclusively dedicated to radiobiological experiments with protons up to 50 MeV. Beam line design, optimisation and initial calculations of flux densities and absorbed doses were undertaken using the Monte Carlo simulation package FLUKA. A proton beam with a flux density of about 10{sup 6} protons/cm{sup 2} s reaches the water sample with a flat lateral distribution of the dose. The absorbed dose at the pristine Bragg peak calculated with FLUKA is 2.4 ± 0.1 Gy in 1 min of irradiation time. This value agrees with the clinically meaningful dose rates, i.e. around 2 Gy/min, used in hadrontherapy. Optimisation and validation studies in the ESS-Bilbao line for radiobiological experiments are detailed in this article.

  15. Application of wavelet analysis to the nuclear phase space study; Application de l`analyse en ondelettes a l`etude de l`espace des phases nucleaire

    Jouault, B. [Nantes Univ., 44 (France)


    The objective of this thesis is to present a methodology, based on the projection methods used in statistical physics and on the wavelet approach, which allows to obtain various classes of information. A coherent modelling was elaborated as the tools used for generating and solving the evolution equations, expressed in terms of pertinent variables, are based on common concepts. The property of scale separation of the wavelet analysis allows an approximation hierarchy based on the geometrical structure of phase space to be defined. This information structuration offers the opportunity of solving the evolution equations with various degrees of precision by controlling the information loss and avoiding the sampling methods of Monte Carlo type. The application of this methodology to the case of heavy ion collisions needs an entirely numerical treatment of the density matrix evolution equation. This implies a very precise level of description in order to take into account the important dissipation effects occurring in intermediate energy nuclear dynamics. A proper solution less expensive was adopted by using the wavelets analytically expressed, this entailing also the testing of model validity by comparing its results with the analytical solutions. This model takes into account the structure of the system wave functions, thus conserving the microscopical information. The present methodology can be applied also at other energy domains providing the nuclear systems are subject to transient non steady-state regimes. The wavelet analysis was used extensively in the field of signal processing particularly to extract from background a physical signal and also in the field of turbulence phenomena 152 refs.

  16. Magnetic resonance studies of solid polymers; Etude des polymeres solides par resonance magnetique

    Lenk, R. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires


    This paper is a review of the application of nuclear magnetic resonance (NMR) to solid polymers. In the first, theoretical part, the elements of the theory of NMR, which are necessary for the study of the properties of solid polymers are discussed: the moments method, nuclear relaxation and the distribution of correlation times. In the second part the experimental results are presented. (author) [French] Cette etude est une recherche bibliographique sur l'application de la resonance magnetique nucleaire (RMN) aux polymeres solides. Dans la premiere partie theorique on discute les elements de la theorie de RMN, necessaires pour l'etude des proprietes des polymeres solides: la methode des moments, la relaxation nucleaire et la distribution des temps de correlation. La deuxieme partie presente les resultats des experiences. (auteur)

  17. Heavy-ion radiobiology: new approaches to delineate mechanisms underlying enhanced biological effectiveness.

    Blakely, E A; Kronenberg, A


    Shortly after the discovery of polonium and radium by Marie Curie and her husband and colleague, Pierre Curie, it was learned that exposure to these alpha-particle emitters produced deleterious biological effects. The mechanisms underlying the increased biological effectiveness of densely ionizing radiations, including alpha particles, neutrons and highly energetic heavy charged particles, remain an active area of investigation. In this paper, we review recent advances in several areas of the radiobiology of these densely ionizing radiations, also known as heavy ions. Advances are described in the areas of DNA damage and repair, chromosome aberrations, mutagenesis, neoplastic transformation in vitro, genomic instability, normal tissue radiobiology and carcinogenesis in vivo. We focus on technical innovations, including novel applications of pulsed-field gel electrophoresis, fluorescence in situ hybridization (FISH), linkage analysis, and studies of gene expression and protein expression. We also highlight the use of new cellular and animal systems, including those with defined DNA repair deficiencies, as well as epithelial cell model systems to assess neoplastic transformation both in vitro and in vivo. The studies reviewed herein have had a substantial impact on our understanding of the genotoxic effects of heavy ions as well as their distinct effects on tissue homeostasis. The use of these radiations in cancer therapy is also discussed. The use of both heavy-ion and proton therapy is on the upswing in several centers around the world, due to their unique energy deposition characteristics that enhance the therapeutic effect and help reduce damage to normal tissue.

  18. Past and Future Work on Radiobiology Mega-Studies: A Case Study At Argonne National Laboratory

    Haley, Benjamin; Wang, Qiong; Wanzer, Beau; Vogt, Stefan; Finney, Lydia; Yang, Ping Liu; Paunesku, Tatjana; Woloschak, Gayle


    Between 1952 and 1992, more than 200 large radiobiology studies were conducted in research institutes throughout Europe, North America, and Japan to determine the effects of external irradiation and internal emitters on the lifespan and tissue toxicity development in animals. At Argonne National Laboratory, 22 external beam studies were conducted on nearly 700 beagle dogs and 50,000 mice between 1969 and 1992. These studies helped to characterize the effects of neutron and gamma irradiation on lifespan, tumorigenesis, and mutagenesis across a range of doses and dosing patterns. The records and tissues collected at Argonne during that time period have been carefully preserved and redisseminated. Using these archived data, ongoing statistical work has been done and continues to characterize quality of radiation, dose, dose rate, tissue, and gender-specific differences in the radiation responses of exposed animals. The ongoing application of newly-developed molecular biology techniques to the archived tissues has revealed gene-specific mutation rates following exposure to ionizing irradiation. The original and ongoing work with this tissue archive is presented here as a case study of a more general trend in the radiobiology megastudies. These experiments helped form the modern understanding of radiation responses in animals and continue to inform development of new radiation models. Recent archival efforts have facilitated open access to the data and materials produced by these studies, and so a unique opportunity exists to expand this continued research.

  19. Heavy-ion radiobiology: new approaches to delineate mechanisms underlying enhanced biological effectiveness

    Blakely, E. A.; Kronenberg, A.; Chatterjee, A. (Principal Investigator)


    Shortly after the discovery of polonium and radium by Marie Curie and her husband and colleague, Pierre Curie, it was learned that exposure to these alpha-particle emitters produced deleterious biological effects. The mechanisms underlying the increased biological effectiveness of densely ionizing radiations, including alpha particles, neutrons and highly energetic heavy charged particles, remain an active area of investigation. In this paper, we review recent advances in several areas of the radiobiology of these densely ionizing radiations, also known as heavy ions. Advances are described in the areas of DNA damage and repair, chromosome aberrations, mutagenesis, neoplastic transformation in vitro, genomic instability, normal tissue radiobiology and carcinogenesis in vivo. We focus on technical innovations, including novel applications of pulsed-field gel electrophoresis, fluorescence in situ hybridization (FISH), linkage analysis, and studies of gene expression and protein expression. We also highlight the use of new cellular and animal systems, including those with defined DNA repair deficiencies, as well as epithelial cell model systems to assess neoplastic transformation both in vitro and in vivo. The studies reviewed herein have had a substantial impact on our understanding of the genotoxic effects of heavy ions as well as their distinct effects on tissue homeostasis. The use of these radiations in cancer therapy is also discussed. The use of both heavy-ion and proton therapy is on the upswing in several centers around the world, due to their unique energy deposition characteristics that enhance the therapeutic effect and help reduce damage to normal tissue.

  20. The photon dose calculation algorithm used in breast radiotherapy has significant impact on the parameters of radiobiological models.

    Petillion, Saskia; Swinnen, Ans; Defraene, Gilles; Verhoeven, Karolien; Weltens, Caroline; Van den Heuvel, Frank


    The comparison of the pencil beam dose calculation algorithm with modified Batho heterogeneity correction (PBC-MB) and the analytical anisotropic algorithm (AAA) and the mutual comparison of advanced dose calculation algorithms used in breast radiotherapy have focused on the differences between the physical dose distributions. Studies on the radiobiological impact of the algorithm (both on the tumor control and the moderate breast fibrosis prediction) are lacking. We, therefore, investigated the radiobiological impact of the dose calculation algorithm in whole breast radiotherapy. The clinical dose distributions of 30 breast cancer patients, calculated with PBC-MB, were recalculated with fixed monitor units using more advanced algorithms: AAA and Acuros XB. For the latter, both dose reporting modes were used (i.e., dose-to-medium and dose-to-water). Next, the tumor control probability (TCP) and the normal tissue complication probability (NTCP) of each dose distribution were calculated with the Poisson model and with the relative seriality model, respectively. The endpoint for the NTCP calculation was moderate breast fibrosis five years post treatment. The differences were checked for significance with the paired t-test. The more advanced algorithms predicted a significantly lower TCP and NTCP of moderate breast fibrosis then found during the corresponding clinical follow-up study based on PBC calculations. The differences varied between 1% and 2.1% for the TCP and between 2.9% and 5.5% for the NTCP of moderate breast fibrosis. The significant differences were eliminated by determination of algorithm-specific model parameters using least square fitting. Application of the new parameters on a second group of 30 breast cancer patients proved their appropriateness. In this study, we assessed the impact of the dose calculation algorithms used in whole breast radiotherapy on the parameters of the radiobiological models. The radiobiological impact was eliminated by

  1. MO-D-BRD-03: Radiobiology and Commissioning of Electronic Brachytherapy for IORT

    Zhang, J. [Oregon Health & Science Univ (United States)


    Electronic brachytherapy (eBT) has seen an insurgence of manufacturers entering the US market for use in radiation therapy. In addition to the established interstitial, intraluminary, and intracavitary applications of eBT, many centers are now using eBT to treat skin lesions. It is important for medical physicists working with electronic brachytherapy sources to understand the basic physics principles of the sources themselves as well as the variety of applications for which they are being used. The calibration of the sources is different from vendor to vendor and the traceability of calibrations has evolved as new sources came to market. In 2014, a new air-kerma based standard was introduced by the National Institute of Standards and Technology (NIST) to measure the output of an eBT source. Eventually commercial treatment planning systems should accommodate this new standard and provide NIST traceability to the end user. The calibration and commissioning of an eBT system is unique to its application and typically entails a list of procedural recommendations by the manufacturer. Commissioning measurements are performed using a variety of methods, some of which are modifications of existing AAPM Task Group protocols. A medical physicist should be familiar with the different AAPM Task Group recommendations for applicability to eBT and how to properly adapt them to their needs. In addition to the physical characteristics of an eBT source, the photon energy is substantially lower than from HDR Ir-192 sources. Consequently, tissue-specific dosimetry and radiobiological considerations are necessary when comparing these brachytherapy modalities and when making clinical decisions as a radiation therapy team. In this session, the physical characteristics and calibration methodologies of eBt sources will be presented as well as radiobiology considerations and other important clinical considerations. Learning Objectives: To understand the basic principles of electronic

  2. Pulsed radiobiology with laser-driven plasma accelerators

    Giulietti, Antonio; Grazia Andreassi, Maria; Greco, Carlo


    Recently, a high efficiency regime of acceleration in laser plasmas has been discovered, allowing table top equipment to deliver doses of interest for radiotherapy with electron bunches of suitable kinetic energy. In view of an R&D program aimed to the realization of an innovative class of accelerators for medical uses, a radiobiological validation is needed. At the present time, the biological effects of electron bunches from the laser-driven electron accelerator are largely unknown. In radiobiology and radiotherapy, it is known that the early spatial distribution of energy deposition following ionizing radiation interactions with DNA molecule is crucial for the prediction of damages at cellular or tissue levels and during the clinical responses to this irradiation. The purpose of the present study is to evaluate the radio-biological effects obtained with electron bunches from a laser-driven electron accelerator compared with bunches coming from a IORT-dedicated medical Radio-frequency based linac's on human cells by the cytokinesis block micronucleus assay (CBMN). To this purpose a multidisciplinary team including radiotherapists, biologists, medical physicists, laser and plasma physicists is working at CNR Campus and University of Pisa. Dose on samples is delivered alternatively by the "laser-linac" operating at ILIL lab of Istituto Nazionale di Ottica and an RF-linac operating for IORT at Pisa S. Chiara Hospital. Experimental data are analyzed on the basis of suitable radiobiological models as well as with numerical simulation based on Monte Carlo codes. Possible collective effects are also considered in the case of ultrashort, ultradense bunches of ionizing radiation.

  3. Toward a consensus on radiobiology teaching to radiation oncology residents.

    Dynlacht, Joseph R; Dewhirst, Mark W; Hall, Eric J; Rosenstein, Barry S; Zeman, Elaine M


    There are approximately 82 radiation oncology residency programs in the United States, which provide training opportunities for about 400 residents. All accredited radiation oncology residency programs must have at least one basic scientist on the faculty, and it is these individuals who often assume, wholly or in part, the responsibility of teaching radiation and cancer biology to radiation oncology residents in preparation for the American College of Radiology (ACR) In-Training Examination in Radiation Oncology and the American Board of Radiology (ABR) written examinations. In response to a perceived lack of uniformity in radiation and cancer biology curricula currently being taught to residents and a perceived lack of guidance for instructors in formulating course content for this population, a special session was presented at the Forty-eighth Annual Radiation Research Society meeting on April 23, 2001. The session, entitled "Toward a Consensus on Radiobiology Teaching to Radiation Oncology Residents", was focused on issues related to teaching radiobiology to radiation oncology residents and targeted for individuals who actively teach radiation and cancer biology as well as coordinators of residency training programs. The speakers addressed current challenges and future problems facing instructors and programs. Among these were lack of feedback on resident performance on ABR and ACR written examinations and on course content, uncertainty about what topics residents must know to pass the ABR examination, and, in the near future, a reduction (due to retirement) of instructors qualified to teach radiobiology. This article provides a synopsis of the information that was presented during that session, offers a glimpse into how the ABR and ACR examinations are prepared and details of the content of past and future examinations, and summarizes the activities of the Joint Working Group on Radiobiology Teaching which was formed to educate instructors, to establish a

  4. (RadioBiological Optimization of External-Beam Radiotherapy

    Alan E. Nahum


    Full Text Available “Biological optimization” (BIOP means planning treatments using (radiobiological criteria and models, that is, tumour control probability and normal-tissue complication probability. Four different levels of BIOP are identified: Level I is “isotoxic” individualization of prescription dose at fixed fraction number. is varied to keep the NTCP of the organ at risk constant. Significant improvements in local control are expected for non-small-cell lung tumours. Level II involves the determination of an individualized isotoxic combination of and fractionation scheme. This approach is appropriate for “parallel” OARs (lung, parotids. Examples are given using our BioSuite software. Hypofractionated SABR for early-stage NSCLC is effectively Level-II BIOP. Level-III BIOP uses radiobiological functions as part of the inverse planning of IMRT, for example, maximizing TCP whilst not exceeding a given NTCP. This results in non-uniform target doses. The NTCP model parameters (reflecting tissue “architecture” drive the optimizer to emphasize different regions of the DVH, for example, penalising high doses for quasi-serial OARs such as rectum. Level-IV BIOP adds functional imaging information, for example, hypoxia or clonogen location, to Level III; examples are given of our prostate “dose painting” protocol, BioProp. The limitations of and uncertainties inherent in the radiobiological models are emphasized.

  5. Experimental radiotherapy and clinical radiobiology. Vol. 20. Proceedings; Experimentelle Strahlentherapie und Klinische Strahlenbiologie. Bd. 20. Proceedings

    Baumann, Michael; Dahm-Daphi, Jochen; Dikomey, Ekkehard; Petersen, Cordula; Rodemannn, Hans-Peter; Zips, Daniel (eds.)


    The proceedings include contributions on the following issues: laser driven proton accelerators on the way for radiotherapy, radiobiological evaluation of new radiations; molecular factors of radiation response; biological targeting; EGFR epidermal growth factor receptor/targeting - combined internal and external irradiation, radiobiology of normal tissues; dose-volume histograms for the radiotherapy: curves without radiobiological relevance or important information for the therapy planning; HPV (human papilloma virus) and radiation sensitivity of HNSCC (head and neck squamous cell carcinomas): evidence, radiobiological mechanism, clinical consequences and perspectives; mechanisms of action and intertumoral heterogeneity of response to EGFR inhibition in radiotherapy of solid tumors; evaluation of biomarkers for radiotherapy.

  6. Etude Sedimentologique et Esquisse Paleoenvironnementale des ...

    Etude Sedimentologique et Esquisse Paleoenvironnementale des ... Les analyses sédimentologiques réalisées dans ce travail, sont un prélude d'un projet d'études pluridisciplinaires ... (Crétacé inférieur) à l'océanisation complète (fin.

  7. A semi-analytical radiobiological model may assist treatment planning in light ion radiotherapy

    Kundrat, Pavel [Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, CZ-182 21 Prague 8 (Czech Republic)


    A semi-analytical model of light ions' Bragg peaks is presented and used in conjunction with a detailed probabilistic radiobiological module to predict the biological effectiveness of light ion irradiation for hadrontherapy applications. The physical Bragg peak model is based on energy-loss calculations with the SRIM code and phenomenological formulae for the energy-loss straggling. Effects of nuclear reactions are accounted for on the level of reducing the number of primary particles only. Reaction products are not followed at all and their contribution to dose deposition is neglected. Beam widening due to multiple scattering and calculations of spread-out Bragg peaks are briefly discussed. With this simple physical model, integral depth-dose distributions are calculated for protons, carbon, oxygen and neon ions. A good agreement with published experimental data is observed for protons and lower energy ions (with ranges in water up to approximately 15 cm), while less satisfactory results are obtained for higher energy ions due to the increased role of nuclear reaction products, neglected in this model. A detailed probabilistic radiobiological module is used to complement the simple physical model and to estimate biological effectiveness along the penetration depth of Bragg peak irradiation. Excellent agreement is found between model predictions and experimental data for carbon beams, indicating potential applications of the present scheme in treatment planning in light ion hadrontherapy. Due to the semi-analytical character of the model, leading to high computational speed, applications are foreseen in particular in the fully biological optimization of multiple irradiation fields and intensity-modulated beams.

  8. A semi-analytical radiobiological model may assist treatment planning in light ion radiotherapy.

    Kundrát, Pavel


    A semi-analytical model of light ions' Bragg peaks is presented and used in conjunction with a detailed probabilistic radiobiological module to predict the biological effectiveness of light ion irradiation for hadrontherapy applications. The physical Bragg peak model is based on energy-loss calculations with the SRIM code and phenomenological formulae for the energy-loss straggling. Effects of nuclear reactions are accounted for on the level of reducing the number of primary particles only. Reaction products are not followed at all and their contribution to dose deposition is neglected. Beam widening due to multiple scattering and calculations of spread-out Bragg peaks are briefly discussed. With this simple physical model, integral depth-dose distributions are calculated for protons, carbon, oxygen and neon ions. A good agreement with published experimental data is observed for protons and lower energy ions (with ranges in water up to approximately 15 cm), while less satisfactory results are obtained for higher energy ions due to the increased role of nuclear reaction products, neglected in this model. A detailed probabilistic radiobiological module is used to complement the simple physical model and to estimate biological effectiveness along the penetration depth of Bragg peak irradiation. Excellent agreement is found between model predictions and experimental data for carbon beams, indicating potential applications of the present scheme in treatment planning in light ion hadrontherapy. Due to the semi-analytical character of the model, leading to high computational speed, applications are foreseen in particular in the fully biological optimization of multiple irradiation fields and intensity-modulated beams.

  9. Les Etudes De Langues Aux Pays-Bas

    Zwarts, F.


    Les Etudes de Langues dans l'Enseignement Superieur en Europe: Des Rapports Nationaux Préparés pour une Conference sur les Etudes de Langues en Europe et Cooperation dans le Domaine de l'Enseignement Superieur à l'Univerité de Stockholm.

  10. Contribution to the study of the geophysical behaviour of lead-210 by application of alpha spectrometry; Contribution a l'etude du comportement geophysique du plomb 210 par application de la spectrometrie alpha

    Nezami, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    A study of the changes in the lead-210 contents of rain-water and of water produced by melting polar ice has required the development of a method for dosing lead-210, an {alpha} emitter. This method is 40 times more sensitive than that which measures the lead-210 by bismuth-210, a ({beta} emitter. The first part of the report presents the study of a spectrometry using semiconductor detectors; a catalogue of a spectra shows the advantages of this method. In the second part will be found at first a new chemical separation method for polonium-210 and the results obtained with this method. The main results obtained on the geophysical behaviour of lead-210 are the following: - the monthly lead-210 and polonium-210 contents in rain water are approximately constant with time. - in the Gif-sur-Yvette region, the clean-up by 'dry fall-out' can attain 40 to 50 per cent of the total fall-out. - a study of Antarctic ice samples makes it possible to determine an annual accumulation rate equivalent to 13.8 cm of water and to show discrepancies in the periodic concentrations which correspond to the latest maxima of solar activity. - a balance is drawn up between the radon produced by the continents and the lead-210 fall-out. (author) [French] Une etude sur les variations de la teneur en plomb 210 des eaux de pluie et des eaux de fusion des glaces polaires a necessite la mise au point d'une methode de dosage du plomb 210 emetteur {alpha}. Cette methode permet d'obtenir une sensibilite quarante fois superieure a celle dosant le plomb 210 par le bismuth 210 emetteur {beta}. La premiere partie du travail presente l'etude de la spectrometrie {alpha} par detecteur a semiconducteurs, un catalogue de spectres {alpha} met en evidence les avantages de cette methode. Dans la deuxieme partie on trouvera en premier lieu une nouvelle methode chimique de separation du polonium 210 ainsi que les resultats obtenus grace a cette methode. Les principaux resultats sur le

  11. The radiobiological principles of boron neutron capture therapy: A critical review

    Hopewell, J.W., E-mail: [Green Templeton College and Particle Therapy Cancer Research Institute, University of Oxford, Oxford (United Kingdom); Morris, G.M. [Medical Department, Brookhaven National Laboratory, Upton, NY (United States); Schwint, A. [Department of Radiobiology, Constituyentes Atomic Center, National Atomic Energy Commission, San Martin, Buenos Aires (Argentina); Coderre, J.A. [Ora Inc, 300 Brickstone Square, Andover, MA (United States)


    The radiobiology of the dose components in a BNCT exposure is examined. The effect of exposure time in determining the biological effectiveness of {gamma}-rays, due to the repair of sublethal damage, has been largely overlooked in the application of BNCT. Recoil protons from fast neutrons vary in their relative biological effectiveness (RBE) as a function of energy and tissue endpoint. Thus the energy spectrum of a beam will influence the RBE of this dose component. Protons from the neutron capture reaction in nitrogen have not been studied but in practice protons from nitrogen capture have been combined with the recoil proton contribution into a total proton dose. The relative biological effectiveness of the products of the neutron capture reaction in boron is derived from two factors, the RBE of the short range particles and the bio-distribution of boron, referred to collectively as the compound biological effectiveness factor. Caution is needed in the application of these factors for different normal tissues and tumors. - Highlights: Black-Right-Pointing-Pointer Radiobiological properties of different dose components in BNCT are considered. Black-Right-Pointing-Pointer Effectiveness of {gamma}-ray dose depends strongly on exposure time due to sublethal damage repair. Black-Right-Pointing-Pointer Effectiveness of fast neutron dose depends on neutron energy spectrum. Black-Right-Pointing-Pointer {gamma}-ray and fast neutron characteristics vary between beams and thus weighting factors will differ. Black-Right-Pointing-Pointer Weighing factors for boron dose depend on the carrier, the tissue and its mode of administration.

  12. Radiobiological and standard data for radioprotection and radiotherapy

    Jammet, H.


    From ninth annual meeting of the European Society for Radiation Biology; Rome, Italy (26 Sep 1972). Radiobiological data provide the scientific bases for radioprotection norms and radiotherapy practices. Nevertheless numerous problems remain unsolved including dosimetry at the cellular and infracellular level, metabolic curves for the purlfication of radionuclides, dose-effect relations for stochastic phenomena, effect of high doses on conjunctive tissue, value of the calibration factor in time, RBE of high energy particles, and radiosensitivity as a function of age and sex. The scope of these problems is briefly indicated. (JSR)

  13. Radiobiological modeling with MarCell software

    Hasan, J.S.; Jones, T.D. [Oak Ridge National Lab., TN (United States). Health Sciences Research Div.


    A nonlinear system of differential equations that models the bone marrow cellular kinetics associated with radiation injury, molecular repair, and compensatory cell proliferation has been extensively documented. Recently, that model has been implemented as MarCell, a user-friendly MS-DOS computer program that allows users with little knowledge of the original model to evaluate complex radiation exposure scenarios. The software allows modeling with the following radiations: tritium beta, 100 kVp X, 250 kVp X, 22 MV X, {sup 60}Co, {sup 137}Cs, 2 MeV electrons, triga neutrons, D-T neutrons, and 3 blends of mixed-field fission radiations. The possible cell lineages are stem, stroma, and leukemia/lymphoma, and the available species include mouse, rat, dog, sheep, swine, burro, and man. An attractive mathematical feature is that any protracted protocol can be expressed as an equivalent prompt dose for either the source used or for a reference, such as 250 kVp X rays or {sup 60}Co. Output from MarCell includes: risk of 30-day mortality; risk of cancer and leukemia based either on cytopenia or compensatory cell proliferation; cell survival plots as a function of time or dose; and 4-week recovery kinetics following treatment. In this article, the program`s applicability and ease of use are demonstrated by evaluating a medical total body irradiation protocol and a nuclear fallout scenario.

  14. Development of a tool computer to compensate for interruptions of treatment and radiobiological comparisons Tr in external radiotherapy; Desarrollo de una herramienta informatica para la compensacion de interrupciones de tratamiento y comparaciones radiobiologicas en radioterapia externa

    Ramos Pacho, J. A.; Sena Espinel, E.; Verde Velasco, J. M.; Garcia Repiso, S.; Perez Alvarez, M. E.; Delgado Apaaricio, J. M.; Martin Rincon, C.; Saez Beltran, M.; Gomez Gonzalez, N.; Cons Perez, N.


    Outages unscheduled in the course of external beam radiation treatments, and the loss of probability of tumour control (TCP), which make it necessary to have a tool that allows the adjustment of the compensation of the absorbed dose required to keep the biological effect on the tumor, controlling the possible impact on the organ at risk. In order to perform this radiobiological quickly setting has been developed a software application that also allows comparison of treatments with different subdivisions from the point of view of radiobiological. (Author)

  15. Realization of radiobiological in vitro cell experiments at conventional X-ray tubes and unconventional radiation sources

    Beyreuther, Elke


    More than hundred years after the discovery of X-rays different kinds of ionizing radiation are ubiquitous in medicine, applied to clinical diagnostics and cancer treatment as well. Irrespective of their nature, the widespread application of radiation implies its precise dosimetric characterization and detailed knowledge of the radiobiological effects induced in cancerous and normal tissue. Starting with in vitro cell irradiation experiments, which define basic parameters for the subsequent tissue and animal studies, the whole multi-stage process is completed by clinical trials that translate the results of fundamental research into clinical application. In this context, the present dissertation focuses on the establishment of radiobiological in vitro cell experiments at unconventional, but clinical relevant radiation qualities. In the first part of the present work the energy dependent biological effectiveness of photons was studied examining low-energy X-rays (≤ 50 keV), as used for mammography, and high-energy photons (≥ 20 MeV) as proposed for future radiotherapy. Cell irradiation experiments have been performed at conventional X-ray tubes providing low-energy photons and 200 kV reference radiation as well. In parallel, unconventional quasi-monochromatic channeling X-rays and high-energy bremsstrahlung available at the radiation source ELBE of the Forschungszentrum Dresden-Rossendorf were considered for radiobiological experimentation. For their precise dosimetric characterization dosimeters based on the thermally stimulated emission of exoelectrons and on radiochromic films were evaluated, whereas just the latter was found to be suitable for the determination of absolute doses and spatial dose distributions at cell position. Standard ionization chambers were deployed for the online control of cell irradiation experiments. Radiobiological effects were analyzed in human mammary epithelial cells on different subcellular levels revealing an increasing amount

  16. Etude de sécurité en base de données avec une application pour le contrôle d’accès

    EL HADJ MIMOUNE, Khadidja


    Dans le cadre de PFE, nous avons réalisé une application qui fait appel à des mécanismes de sécurité dans le cadre des bases de données. Notre application contient deux parties : la première est une application Web réalisée pour gérer les clients dans un environnement 3-tiers, nous avons proposé dans cette partie un contrôle d’accès sur le nombre de tentatives erronés d’authentification avant de désactiver un compte existant ainsi qu’un mécanisme de chiffrement afin de protéger les informatio...

  17. REVIEW: Development of radiobiology for oncology—a personal view

    Fowler, Jack F.


    When I came into radiotherapy in 1950, I was puzzled that some patients were treated to 3000 rads (cGy) in 3 weeks but others received 4000 in 5 or 6000 in 6 weeks. When I asked why, there were no convincing answers given, except 'this is what we usually do'. It wasn't until I went to a course on 'Radiobiology for Radiotherapy' in Cambridge that I learnt about the basic theories of Douglas Lea and the very considerable history of research into radiobiology and clinical radiotherapy. And there were still some questions outstanding, such as the relative importance of intracellular repair between 'daily' fractions, whether a 2 day gap each week was a good or a bad idea, and the role of proliferation, if any, during irradiation. I thought that a few simple animal experiments might help to give answers! That led me to a continuing interest in these questions and answers, which has taken me more than 50 years to pursue. This is the very personal story of what I saw happening in the subject, decade by decade. I was happy to experience all this together with scientists in many other countries, and our own, along the way.

  18. Hypofractionation in Prostate Cancer: Radiobiological Basis and Clinical Appliance

    M. Mangoni


    Full Text Available External beam radiation therapy with conventional fractionation to a total dose of 76–80 Gy represents the most adopted treatment modality for prostate cancer. Dose escalation in this setting has been demonstrated to improve biochemical control with acceptable toxicity using contemporary radiotherapy techniques. Hypofractionated radiotherapy and stereotactic body radiation therapy have gained an increasing interest in recent years and they have the potential to become the standard of care even if long-term data about their efficacy and safety are not well established. Strong radiobiological basis supports the use of high dose for fraction in prostate cancer, due to the demonstrated exceptionally low values of α/β. Clinical experiences with hypofractionated and stereotactic radiotherapy (with an adequate biologically equivalent dose demonstrated good tolerance, a PSA control comparable to conventional fractionation, and the advantage of shorter time period of treatment. This paper reviews the radiobiological findings that have led to the increasing use of hypofractionation in the management of prostate cancer and briefly analyzes the clinical experience in this setting.

  19. Hypofractionation in prostate cancer: radiobiological basis and clinical appliance.

    Mangoni, M; Desideri, I; Detti, B; Bonomo, P; Greto, D; Paiar, F; Simontacchi, G; Meattini, I; Scoccianti, S; Masoni, T; Ciabatti, C; Turkaj, A; Serni, S; Minervini, A; Gacci, M; Carini, M; Livi, L


    External beam radiation therapy with conventional fractionation to a total dose of 76-80 Gy represents the most adopted treatment modality for prostate cancer. Dose escalation in this setting has been demonstrated to improve biochemical control with acceptable toxicity using contemporary radiotherapy techniques. Hypofractionated radiotherapy and stereotactic body radiation therapy have gained an increasing interest in recent years and they have the potential to become the standard of care even if long-term data about their efficacy and safety are not well established. Strong radiobiological basis supports the use of high dose for fraction in prostate cancer, due to the demonstrated exceptionally low values of α / β . Clinical experiences with hypofractionated and stereotactic radiotherapy (with an adequate biologically equivalent dose) demonstrated good tolerance, a PSA control comparable to conventional fractionation, and the advantage of shorter time period of treatment. This paper reviews the radiobiological findings that have led to the increasing use of hypofractionation in the management of prostate cancer and briefly analyzes the clinical experience in this setting.

  20. Influence of oxygen on the chemical stage of radiobiological mechanism

    Barilla, Jiří; Lokajíček, Miloš V.; Pisaková, Hana; Simr, Pavel


    The simulation of the chemical stage of radiobiological mechanism may be very helpful in studying the radiobiological effect of ionizing radiation when the water radical clusters formed by the densely ionizing ends of primary or secondary charged particle may form DSBs damaging DNA molecules in living cells. It is possible to study not only the efficiency of individual radicals but also the influence of other species or radiomodifiers (mainly oxygen) being present in water medium during irradiation. The mathematical model based on Continuous Petri nets (proposed by us recently) will be described. It makes it possible to analyze two main processes running at the same time: chemical radical reactions and the diffusion of radical clusters formed during energy transfer. One may study the time change of radical concentrations due to the chemical reactions running during diffusion process. Some orientation results concerning the efficiency of individual radicals in DSB formation (in the case of Co60 radiation) will be presented; the influence of oxygen present in water medium during irradiation will be shown, too.

  1. An irradiation facility with a vertical beam for radiobiological studies

    Besserer, J; Dellert, M; Gahn, C; Moosburger, M; Pemler, P; Quicken, P; Distel, L; Schuessler, H


    A vertical beam facility for radiobiological experiments was designed and constructed at the Munich Tandem-Accelerator Laboratory. The main part of the facility is a 90 deg. dipole magnet bending the beam of protons or heavy particles into a vertical upward direction, which is advantageous for wet-cell irradiation. After collimation the beam is spread out passively by thin scattering foils and dynamically by magnetic coils. A homogeneity of the radiation field better than +-5% has been achieved over the diameter of the exit window of 60 mm. The dose rate can be widely adjusted from single particles to more than 10 sup 1 sup 0 particles (i.e. hundreds of Grays) per second. The dose measurement is based on single-particle counting and on standard dosimeters. The detector system for dosimetry and irradiation control is described. In a first radiobiological experiment the cell survival of chinese hamster cells was measured after irradiation with 22.7 MeV protons and compared with the X-ray result.

  2. Gestion efficace de s\\'eries temporelles en P2P: Application \\`a l'analyse technique et l'\\'etude des objets mobiles

    Gardarin, Georges; Yeh, Laurent; Zeitouni, Karine; Butnaru, Bogdan; Sandu-Popa, Iulian


    In this paper, we propose a simple generic model to manage time series. A time series is composed of a calendar with a typed value for each calendar entry. Although the model could support any kind of XML typed values, in this paper we focus on real numbers, which are the usual application. We define basic vector space operations (plus, minus, scale), and also relational-like and application oriented operators to manage time series. We show the interest of this generic model on two applications: (i) a stock investment helper; (ii) an ecological transport management system. Stock investment requires window-based operations while trip management requires complex queries. The model has been implemented and tested in PHP, Java, and XQuery. We show benchmark results illustrating that the computing of 5000 series of over 100.000 entries in length - common requirements for both applications - is difficult on classical centralized PCs. In order to serve a community of users sharing time series, we propose a P2P imple...

  3. Treatment plan comparison between helical tomotherapy and MLC-based IMRT using radiobiological measures

    Mavroidis, Panayiotis [Department of Medical Radiation Physics, Karolinska Institutet and Stockholm University (Sweden); Ferreira, Brigida Costa [Department of Medical Radiation Physics, Karolinska Institutet and Stockholm University (Sweden); Shi, Chengyu [Department of Radiation Oncology, University of Texas Health Science Center, San Antonio, TX (United States); Lind, Bengt K [Department of Medical Radiation Physics, Karolinska Institutet and Stockholm University (Sweden); Papanikolaou, Nikos [Department of Radiation Oncology, University of Texas Health Science Center, San Antonio, TX (United States)


    The rapid implementation of advanced treatment planning and delivery technologies for radiation therapy has brought new challenges in evaluating the most effective treatment modality. Intensity-modulated radiotherapy (IMRT) using multi-leaf collimators (MLC) and helical tomotherapy (HT) are becoming popular modes of treatment delivery and their application and effectiveness continues to be investigated. Presently, there are several treatment planning systems (TPS) that can generate and optimize IMRT plans based on user-defined objective functions for the internal target volume (ITV) and organs at risk (OAR). However, the radiobiological parameters of the different tumours and normal tissues are typically not taken into account during dose prescription and optimization of a treatment plan or during plan evaluation. The suitability of a treatment plan is typically decided based on dosimetric criteria such as dose-volume histograms (DVH), maximum, minimum, mean and standard deviation of the dose distribution. For a more comprehensive treatment plan evaluation, the biologically effective uniform dose D-bar is applied together with the complication-free tumour control probability (P{sub +}). Its utilization is demonstrated using three clinical cases that were planned with two different forms of IMRT. In this study, three different cancer types at different anatomical sites were investigated: head and neck, lung and prostate cancers. For each cancer type, a linac MLC-based step-and-shoot IMRT plan and a HT plan were developed. The MLC-based IMRT treatment plans were developed on the Philips treatment-planning platform, using the Pinnacle 7.6 software release. For the tomotherapy HiArt plans, the dedicated tomotherapy treatment planning station was used, running version 2.1.2. By using D-bar as the common prescription point of the treatment plans and plotting the tissue response probabilities versus D-bar for a range of prescription doses, a number of plan trials can be

  4. Study of secondary electronic emission in some piezo-electric materials: application to ultrasonic visualization; Etude de l'emission electronique secondaire de quelques materiaux piezoelectriques: application a la visualisation ultrasonore

    Marini, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    Methods allowing the visualization of acoustic images appear at the moment to be of great interest in the field of non-destructive testing as well as in that of underwater detection. In order to carry out certain calculations on the operation of an ultrasonic camera, it has been necessary to study the secondary electron emission of some piezoelectric materials liable to be incorporated into the equipment. The secondary electron emission of insulators is a rather complex phenomenon; in order to find a rational explanation for the observations made, a theory has been developed for the energy spectrum of the emitted electrons. The experimental results of this work have then been used to build an ultrasonic visualization installation. Some examples of acoustic images which have been visualized are also presented. (author) [French] Les methodes qui permettent de visualiser des images acoustiques trouvent a l'heure actuelle un grand interet dans le domaine du controle non destructif comme dans celui de la detection sous-marine. De maniere a effectuer certains calculs sur le fonctionnement d'une camera ultrasons, il a ete necessaire d'etudier l'emission electronique secondaire de quelques materiaux piezoelectriques susceptibles d'etre utilises dans sa construction. L'emission electronique secondaire des isolants est un phenomene assez complexe et de maniere a trouver des explications coherentes aux observations effectuees, une theorie du spectre energetique des electrons emis a ete elaboree. Une installation de visualisation ultrasonore a alors ete realisee a partir des donnees experimentales de cette etude. Quelques exemples d'images acoustiques visualisees par cette methode sont egalement presentees. (auteur)

  5. Study of the behaviour of artificial radioactive aerosols. Applications to some problems of atmospheric circulation (1963); Etude du comportement dcs aerosols radioactifs artificiels. Applications a quelques problemes de circulation atmospherique (1963)

    Lambert, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    The aim of this work, consists in the examination of the behaviour of radioactive aerosols produced in the atmosphere by nuclear explosions, in order to deduce the most general laws governing atmospheric circulation and diffusion. After having given a general table of the radioactive aerosols present the authors consider the validity and the precision of the measurement methods and the concentration of the aerosols at ground level and in the upper atmosphere, as well as their deposition on the ground. The existence is thus demonstrated of a tropospheric equatorial barrier and of discontinuous and seasonal aspects of stratosphere-troposphere transfers. The role is shown of precipitations and dry auto-filtration in the lower atmosphere cleaning processes. This work makes it possible to describe the general behaviour of dust from the stratosphere, and to improve the total radioactive contamination of the globe. (author) [French] L'objectif de ce travail consiste a examiner le comportement des aerosols radioactifs introduits dans l'atmosphere par les explosions nucleaires, pour en deduire les lois les plus generals de la circulation et diffusion atmospheriques. Apres avoir dresse un tableau d'ensemble des aerosols radioactifs presents, on examine la validite et la precision des methodes de mesure de leur concentration, au niveau du sol et en haute atmosphere, ainsi que de leur depot a la surface du sol. On met ainsi en evidence l'existence d'une barriere equatoriale tropospherique; l'aspect discontinu et saisonnier des transferts stratosphere-troposphere; le role des precipitations et de l'auto-filtration seche, dans les processus de nettoyage de la basse atmosphere. Ces etudes permettent de decrire le comportement general des poussieres d'origine stratospherique et d'ameliorer le bilan de la contamination radioactive du globe. (auteur)

  6. Characterization and performances of DOSION, a dosimetry equipment dedicated to radiobiology experiments taking place at GANIL

    Boissonnat, G; Balanzat, E; Boumard, F; Carniol, B; Colin, J; Cussol, D; Etasse, D; Fontbonne, C; Frelin, A -M; Hommet, J; Peronnel, J; Salvador, S


    Currently, radiobiology experiments using heavy ions at GANIL(Grand Acc\\'el\\'erateur National d'Ions Lourds) are conducted under the supervision of the CIMAP (Center for research on Ions, MAterials and Photonics). In this context, a new beam monitoring equipment named DOSION has been developed. It allows to perform measurements of accurate fluence and dose maps in near real time for each biological sample irradiated. In this paper, we present the detection system, its design, performances, calibration protocol and measurements performed during radiobiology experiments. This setup is currently available for any radiobiology experiments if one wishes to correlate one's own sample analysis to state of the art dosimetric references.

  7. Operation and Maintenance of the National Radiobiology Archives

    Dr. Anthony C. James; Stacey L. McCord


    The National Radiobiology Archives (NRA) are an archival program, started in 1989, to collect, organize and maintain data, laboratory notebooks, and animal tissue specimens from government (Department of Energy and its predecessor agencies) sponsored radiobiology life-span animal studies. These unique records, histopathology slides and paraffin embedded tissue blocks are maintained in a central facility and are available for further research study. The materials include electronic and paper records for each of more than 6,000 life-span-observations on dogs as well as details of major studies involving nearly 30,000 mice. Although these studies were performed over many years and at different laboratories with differing data management systems, the NRA has translated them into a standardized set of relational database tables. These can be distributed to interested individuals on written request. Specific Aims are: (1) To Maintain the Archive of Written Records from the Animal Experiments - The USTUR continued to maintain the NRA archives which consist of approximately 175 storage boxes containing laboratory notebooks, animal exposure records, animal pathologic records, and radiographs. These were stored in a 6,000 square foot leased facility in Richland, WA. Additionally, through a collaboration with Pacific Northwest National Laboratory's (PNNL) Low Dose Program, many of these records were scanned into digital files. These totaled 34 GB of data, which are saved in 2,407 separate PDF files that are organized by box number and animal identification number. (2) To Maintain the Archive of Animal Tissues at Washington State University - The USTUR continued to house the NRA dog tissue collection in the leased facility. The NRA tissue collection consisted of pathology slides and tissue blocks. Approximately 25% of the laboratory facility was dedicated to the storage of the NRA materials. (3) To Organize the Datasets of These Animals in the Context of Other Datasets so

  8. Preparation of laser-accelerated proton beams for radiobiological applications

    Metzkes, J., E-mail: [Forschungszentrum Dresden-Rossendorf (FZD), 01314 Dresden (Germany); Cowan, T.E. [Forschungszentrum Dresden-Rossendorf (FZD), 01314 Dresden (Germany); Karsch, L. [OncoRay - National Center for Radiation Research in Oncology, TU Dresden, Fetscherstr. 74, 01307 Dresden (Germany); Kraft, S.D. [Forschungszentrum Dresden-Rossendorf (FZD), 01314 Dresden (Germany); Pawelke, J.; Richter, C. [Forschungszentrum Dresden-Rossendorf (FZD), 01314 Dresden (Germany); OncoRay - National Center for Radiation Research in Oncology, TU Dresden, Fetscherstr. 74, 01307 Dresden (Germany); Richter, T.; Zeil, K. [Forschungszentrum Dresden-Rossendorf (FZD), 01314 Dresden (Germany); Schramm, U., E-mail: [Forschungszentrum Dresden-Rossendorf (FZD), 01314 Dresden (Germany)


    This paper presents the concept of transport and filtering of laser-accelerated proton pulses used for the first cell irradiation experiments performed with the Dresden 150 TW laser DRACO. Based on a simple non-focusing magnetic dipole equipped with two apertures the concept makes use of an energy dependent angular asymmetry of the proton spectra. For micron thin target foils protons of interest with energies above 7 MeV are observed to be significantly offset from target normal where low energy emission is dominantly centered. As the effect can be controlled via the target rotation with respect to the incoming light, it can be used to optimize the transport efficiency for high energy protons while simultaneously suppressing background radiation.

  9. Etude des parametres physiques en vue d'applications medicales de l'actionnement magnetique de dispositifs medicaux par un systeme d'imagerie par resonance magnetique

    Mathieu, Jean-Baptiste

    An actuation and control method for medical devices based on the magnetic gradient coils of a Magnetic Resonance Imaging (MRI) was proposed for the first time in 2002 by NanoRobotics Laboratory [1]. The work undertaken in the present thesis began in the context of demonstrating the concept of automatic navigation of a magnetic bead in vivo. From the point of view of actuation, models and experimental data correlate. A maximum velocity of 13cm/s was measured for a 1.5mm diameter chrome steel bead in the carotid artery of a living swine. The bead was under the influence of magnetic gradients applied by a clinical MRI system without any hardware modification. In light of these results, the aim of this thesis is the study of the physical parameters involved in the development of a first medical application: the steering of magnetic particles in MRI in the context of drug targeting. It was demonstrated that an MRI system equipped with a set of magnetic gradient coils with enhanced amplitude was able to apply a high enough actuation force to act upon magnetic microparticles suspended in a liquid. General rules for MRI actuation were identified. First of all, increasing the amplitude of the main magnetic field of the MRI leads to the increase of the actuation force amplitude only until the ferromagnetic body reaches its saturation magnetization. Moreover, soft ferromagnetic bodies appear to be better candidates for MRI based magnetic actuation because they can reach high saturation magnetizations. Magnetic gradient amplitude appears as a foremost factor to increase the amplitude of the magnetic force. Clinical MRI systems do not provide gradients with high enough amplitude for the applications studied here. Theoretical models developed in this thesis predict that a one order of magnitude increase in gradient amplitude would be required. Implementing actuation dedicated gradient coils is therefore suggested. Finally, a larger ferromagnetic body will lead to higher

  10. Synthetic diamond devices for medical dosimetry applied to radiotherapy; Etude et developpement de dispositifs en diamant synthetique pour la dosimetrie medicale: applications en radiotherapie

    Descamps, C


    The aim of this thesis, lead in the framework of an integrated European project entitled M.A.E.S.T.R.O. for ' Methods and Advanced Equipment for Simulation and Treatment in Radio Oncology', was to develop and test synthetic diamond detector in clinical environment for new modalities used in radiotherapy. Diamond is a good candidate for the detection of high energy beams in medical fields. It can be used for passive dosimetry, as thermoluminescent dosimeters or for active dosimetry as ionisation chambers. These two applications are presented here. Concerning the thermoluminescence, several impurities or dopants (boron, phosphorus, and nitrogen) have been incorporated in the diamond films during growth, in order to modify the material dosimetric properties and a detailed study of nitrogen-containing films is proposed. The second part presents the results obtained in active dosimetry. Two guide lines were followed: the measurement set-up optimisation and the material modification. The first dosimetric studies under radiotherapy beams concerning nitrogen-containing polycrystalline diamond as well as high purity single crystal diamond are conclusive. The detectors behaviours are in agreement with the recommendations of the International Atomic Energy Agency (IAEA). (author)

  11. Method for validating radiobiological samples using a linear accelerator

    Brengues, Muriel [The University of Arizona College of Medicine, Center for Applied NanoBioscience and Medicine, Phoenix, AZ (United States); Liu, David; Korn, Ronald [Scottsdale Clinical Research Institute, Scottsdale Healthcare, Scottsdale, AZ (United States); Zenhausern, Frederic [The University of Arizona College of Medicine, Center for Applied NanoBioscience and Medicine, Phoenix, AZ (United States); Scottsdale Clinical Research Institute, Scottsdale Healthcare, Scottsdale, AZ (United States)


    There is an immediate need for rapid triage of the population in case of a large scale exposure to ionizing radiation. Knowing the dose absorbed by the body will allow clinicians to administer medical treatment for the best chance of recovery for the victim. In addition, today's radiotherapy treatment could benefit from additional information regarding the patient's sensitivity to radiation before starting the treatment. As of today, there is no system in place to respond to this demand. This paper will describe specific procedures to mimic the effects of human exposure to ionizing radiation creating the tools for optimization of administered radiation dosimetry for radiotherapy and/or to estimate the doses of radiation received accidentally during a radiation event that could pose a danger to the public. In order to obtain irradiated biological samples to study ionizing radiation absorbed by the body, we performed ex-vivo irradiation of human blood samples using the linear accelerator (LINAC). The LINAC was implemented and calibrated for irradiating human whole blood samples. To test the calibration, a 2 Gy test run was successfully performed on a tube filled with water with an accuracy of 3% in dose distribution. To validate our technique the blood samples were ex-vivo irradiated and the results were analyzed using a gene expression assay to follow the effect of the ionizing irradiation by characterizing dose responsive biomarkers from radiobiological assays. The response of 5 genes was monitored resulting in expression increase with the dose of radiation received. The blood samples treated with the LINAC can provide effective irradiated blood samples suitable for molecular profiling to validate radiobiological measurements via the gene-expression based biodosimetry tools. (orig.)

  12. Detection and analysis of neutral and charged particles. Application to the study of hot plasmas; Detection et analyse des particules chargees et neutres appliquees a l'etude des plasmas chauds

    Renaud, C. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires. Groupe de recherches de l' association EURATOM-CEA sur la fusion controlee


    To measure the energy spectrum of ions in a plasma, one must extract the ions without altering the spectrum. For a dense plasma this presents difficulties, one method is the measurement of the energy spectrum of atoms produced by charge-exchange reactions of ions with residual gas. The measurements of both the energy spectrum and the flux of atoms leaving the magnetic configuration of the device DECA II (Dispositif d'Etude de Compression Adiabatique) are made by: an ion detector which permits the measurement of ion currents {>=} 10{sup -16} A, an electrostatic analyser of energy range 10 eV - 10 keV, a magnetic analyser for ion momentum {<=} 10{sup 5} gauss-cm, and a gas cell to convert fast atoms into ions. (author) [French] Pour mesurer le spectre en energie des ions dans un plasma on doit extraire des ions sans en modifier l'energie. Dans le cas de plasmas denses cela presente certaines difficultes. Une mesure du spectre en energie des ions est alors possible a partir du spectre en energie des atomes produits par collision d'echange de charge entre les ions du plasma et le gaz residuel. Pour effectuer la mesure du spectre en energie et du flux d'atomes s'echappant de la configuration magnetique du Dispositif d'Etude de Compression Adiabatique (DECA II) nous avons mis au point: un detecteur d'ions permettant la mesure de courant {>=} 10{sup -16} A, d'un analyseur electrostatique dont la gamme d'analyse en energie est comprise entre 10 eV et 10 keV, d'un analyseur magnetique capable d'analyser des ions d'une quantite de mouvement {<=} 10{sup 5} gauss cm, ainsi qu'une cellule a gaz permettant l'ionisation des atomes rapides. (auteur)

  13. The radiobiology of laser-driven particle beams: focus on sub-lethal responses of normal human cells

    Manti, L.; Perozziello, F. M.; Borghesi, M.; Candiano, G.; Chaudhary, P.; Cirrone, G. A. P.; Doria, D.; Gwynne, D.; Leanza, R.; Prise, K. M.; Romagnani, L.; Romano, F.; Scuderi, V.; Tramontana, A.


    Accelerated proton beams have become increasingly common for treating cancer. The need for cost and size reduction of particle accelerating machines has led to the pioneering investigation of optical ion acceleration techniques based on laser-plasma interactions as a possible alternative. Laser-matter interaction can produce extremely pulsed particle bursts of ultra-high dose rates (>= 109 Gy/s), largely exceeding those currently used in conventional proton therapy. Since biological effects of ionizing radiation are strongly affected by the spatio-temporal distribution of DNA-damaging events, the unprecedented physical features of such beams may modify cellular and tissue radiosensitivity to unexplored extents. Hence, clinical applications of laser-generated particles need thorough assessment of their radiobiological effectiveness. To date, the majority of studies have either used rodent cell lines or have focussed on cancer cell killing being local tumour control the main objective of radiotherapy. Conversely, very little data exist on sub-lethal cellular effects, of relevance to normal tissue integrity and secondary cancers, such as premature cellular senescence. Here, we discuss ultra-high dose rate radiobiology and present preliminary data obtained in normal human cells following irradiation by laser-accelerated protons at the LULI PICO2000 facility at Laser Lab Europe, France.

  14. The study by means of a photomultiplier of the scintillations produced by {alpha} particles striking a zinc sulphide screen; Etude, au photomultiplicateur, des scintillations produites par les particules {alpha} dans un ecran de sulfure de zinc. Application a la numeration precise des particules {alpha}

    Anthony, J.P. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    The object of the study is the accurate counting of {alpha} particles by p-m. detection of their scintillations upon impact with a zinc sulphide screen. The main advantage of the method is the extreme simplicity of the electronics used: the possibility of obtaining a utilizable pulse from the p-m. (EMI5311) without any amplification, and in linear response, is demonstrated. The scintillation produced by an impact on Zn-S has also been studied experimentally. The decrease of light intensity in relation to time may be interpreted by the exponential relation: I = I{sub 0} exp (-t / {tau}) whereby {tau} = (39 {+-} 0,1) 10{sup -6} s. The relation between scintillation intensity and remaining trajectory after travel through a given air-space has also been determined. Possible suitable applications of this method of {alpha} counting are those where good stability and low background are necessary. Results stated bear on air contamination studies, isotopic composition variation measurement of uranium, bismuth content measurement in alloys by irradiation of specimens in a thermal neutron flux and {alpha} count on the Po formed. (author) [French] Ce travail est consacre a l'etude de la numeration precise des particules {alpha} par detection au photomultiplicateur des scintillations produites par ces particules dans un ecran de sulfure de zinc. Le principal avantage de cette methode reside dans l'extreme simplicite de l'appareillage electronique; il est en effet montre qu'il est possible, tout en convoyant une reponse lineaire, d'obtenir du photomultiplicateur (EMI5311) un signal electrique utilisable sans aucune amplification. La scintillation produite par l'impact des particules {alpha} sur un ecran de Zn-S est etudiee experimentalement. La decroissance de l'intensite lumineuse en fonction du temps est interpretable par la relation exponentielle I = I{sub 0} exp (-t / {tau}) avec {tau} = (39 {+-} 0,1) 10{sup -6} s. La relation entre l

  15. A study of internal contamination levels resulting from {sup 90}Sr and {sup 137}Cs environmental pollution. The influence of different factors; Etude des niveaux de contamination interne resultant d'une pollution de l'environnement par le {sup 90}Sr et le {sup 137}Cs influence des differents parametres

    Garnier, A. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires


    This study includes two parts. The purpose of the former one is to try and evaluate the amounts of {sup 90}Sr and {sup 137}Cs dietary intakes as a function of age with a view to assessing internal exposure doses and estimating the critical age, and to study the relative significance of the several factors it depends on. The data used are both the results of dietary surveys made in 11 districts of the European community from which the evolution of the consumed amounts of 13 groups of foodstuffs, as a function of age was derived, and the mean factors of contamination pathways. The variability of some factors is very large and an attempt is made to assess their significance on the whole contamination; also, the influence of the various diets has been emphasized. The purpose of the second part is to assess, doses as a function of age in the case of protracted exposure on the basis of the aforesaid results and radiobiological factors derived from bibliographic states of the arts. An assessment is made of body burdens and mean doses (either to the skeleton or the whole body according to the radionuclides) originating either from a direct unitary exposure or from situations implying both modes of exposure. As assumed only the diets vary with the districts, thus the results reflect their significance which should be corrected, for a more accurate assessment of the dose variability, by the significance of human and transfer factors. (author) [French] Cette etude comprend deux parties. L'objet de la premiere partie est a la fois un essai d'evaluation en fonction de l'age des quantites de strontium 90 et de cesium 137 ingerees avec les aliments dans la perspective d'une application a l'estimation des doses d'irradiation interne et a la recherche de l'age critique, et une etude de l'influence relative des divers parametres dont elle depend. Les donnees utilisees sont, d'une part, les resultats des enquetes alimentaires faites en

  16. A study of the radiobiological modeling of the conformal radiation therapy in cancer treatment

    Pyakuryal, Anil Prasad

    Cancer is one of the leading causes of mortalities in the world. The precise diagnosis of the disease helps the patients to select the appropriate modality of the treatments such as surgery, chemotherapy and radiation therapy. The physics of X-radiation and the advanced imaging technologies such as positron emission tomography (PET) and computed tomography (CT) plays an important role in the efficient diagnosis and therapeutic treatments in cancer. However, the accuracy of the measurements of the metabolic target volumes (MTVs) in the PET/CT dual-imaging modality is always limited. Similarly the external beam radiation therapy (XRT) such as 3D conformal radiotherapy (3DCRT) and intensity modulated radiation therapy (IMRT) is the most common modality in the radiotherapy treatment. These treatments are simulated and evaluated using the XRT plans and the standard methodologies in the commercial planning system. However, the normal organs are always susceptible to the radiation toxicity in these treatments due to lack of knowledge of the appropriate radiobiological models to estimate the clinical outcomes. We explored several methodologies to estimate MTVs by reviewing various techniques of the target volume delineation using the static phantoms in the PET scans. The review suggests that the more precise and practical method of delineating PET MTV should be an intermediate volume between the volume coverage for the standardized uptake value (SUV; 2.5) of glucose and the 50% (40%) threshold of the maximum SUV for the smaller (larger) volume delineations in the radiotherapy applications. Similarly various types of optimal XRT plans were designed using the CT and PET/CT scans for the treatment of various types of cancer patients. The qualities of these plans were assessed using the universal plan-indices. The dose-volume criteria were also examined in the targets and organs by analyzing the conventional dose-volume histograms (DVHs). The biological models such as tumor

  17. A comparative analysis of radiobiological models for cell surviving fractions at high doses.

    Andisheh, B; Edgren, M; Belkić, Dž; Mavroidis, P; Brahme, A; Lind, B K


    for the cell surviving fractions are exponentials at low as well as high doses, and this is in agreement with the behaviour of the corresponding experimental data. This is an important improvement over the LQ model which predicts a Gaussian at high doses. Overall and for the highlighted reasons, it was concluded that the PLQ, USC and LQL models are theoretically well-founded. They could prove useful compared to the other proposed radiobiological models in clinical applications for obtaining uniformly accurate cell surviving fractions encountered in stereotactic high-dose radiotherapy as well as at medium and low doses.

  18. Novel Radiobiological Gamma Index for Evaluation of 3-Dimensional Predicted Dose Distribution

    Sumida, Iori, E-mail: [Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka (Japan); Yamaguchi, Hajime; Kizaki, Hisao; Aboshi, Keiko; Tsujii, Mari; Yoshikawa, Nobuhiko; Yamada, Yuji [Department of Radiation Oncology, NTT West Osaka Hospital, Osaka (Japan); Suzuki, Osamu; Seo, Yuji [Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka (Japan); Isohashi, Fumiaki [Department of Radiation Oncology, NTT West Osaka Hospital, Osaka (Japan); Yoshioka, Yasuo [Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka (Japan); Ogawa, Kazuhiko [Department of Radiation Oncology, NTT West Osaka Hospital, Osaka (Japan)


    Purpose: To propose a gamma index-based dose evaluation index that integrates the radiobiological parameters of tumor control (TCP) and normal tissue complication probabilities (NTCP). Methods and Materials: Fifteen prostate and head and neck (H&N) cancer patients received intensity modulated radiation therapy. Before treatment, patient-specific quality assurance was conducted via beam-by-beam analysis, and beam-specific dose error distributions were generated. The predicted 3-dimensional (3D) dose distribution was calculated by back-projection of relative dose error distribution per beam. A 3D gamma analysis of different organs (prostate: clinical [CTV] and planned target volumes [PTV], rectum, bladder, femoral heads; H&N: gross tumor volume [GTV], CTV, spinal cord, brain stem, both parotids) was performed using predicted and planned dose distributions under 2%/2 mm tolerance and physical gamma passing rate was calculated. TCP and NTCP values were calculated for voxels with physical gamma indices (PGI) >1. We propose a new radiobiological gamma index (RGI) to quantify the radiobiological effects of TCP and NTCP and calculate radiobiological gamma passing rates. Results: The mean RGI gamma passing rates for prostate cases were significantly different compared with those of PGI (P<.03–.001). The mean RGI gamma passing rates for H&N cases (except for GTV) were significantly different compared with those of PGI (P<.001). Differences in gamma passing rates between PGI and RGI were due to dose differences between the planned and predicted dose distributions. Radiobiological gamma distribution was visualized to identify areas where the dose was radiobiologically important. Conclusions: RGI was proposed to integrate radiobiological effects into PGI. This index would assist physicians and medical physicists not only in physical evaluations of treatment delivery accuracy, but also in clinical evaluations of predicted dose distribution.

  19. Feasibility of BNCT radiobiological experiments at the HYTHOR facility

    Esposito, J.; Ceballos, C.; Soncin, M.; Fabris, C.; Friso, E.; Moro, D.; Colautti, P.; Jori, G.; Rosi, G.; Nava, E.


    HYTHOR (HYbrid Thermal spectrum sHifter tapirO Reactor) is a new thermal-neutron irradiation facility, which was installed and became operative in mid 2005 at the TAPIRO (TAratura PIla Rapida potenza 0) fast reactor, in the Casaccia research centre (near Rome) of ENEA (Ente per le Nuove tecnologie Energia ed Ambiente). The facility has been designed for in vivo radiobiological studies. In HYTHOR irradiation cavity, 1-6 mice can be simultaneously irradiated to study skin melanoma treatments with the BNCT (boron neutron capture therapy). The therapeutic effects of HYTHOR radiation field on mouse melanoma has been studied as a preliminary investigation before studying the tumour local control due to boron neutron capture effect after boronated molecule injection. The method to properly irradiate small animals has been precisely defined. Results show that HYTHOR radiation field is by itself effective in reducing the tumour-growth rate. This finding has to be taken into account in studying the effectiveness of new 10B carriers. A method to properly measure the reduction of the tumour-growth rate is reported and discussed.

  20. Amchitka Radiobiological Program progress report, January 1979-December 1979

    Thornberg, L.D.; Sibley, T.H.; Nakatani, R.E.


    The objective of the Amchitka Radiobiological Program for the period 1970-1979 was to determine the extent of radionuclide contamination from world-wide atmospheric fallout and from the detonation of three underground nuclear blasts on Amchitka Island. The objective is achieved, by the collection and radiological analyses of biological and environmental samples and by background radiation measurements. Leakage of radionuclides from the underground sites of the Amchitka nuclear detonations would be suspected if the contamination was significntly greater than would be expected from world fallout. An account of the program from July 1970 to December 1978 has been given in nine previous reports from the Laboratory of Radiation Ecology to the Nevada Operations Office of the US Department of Energy. This report is an account of the program for calendar year 1979. The results of analyses of the samples collected in 1979 lead to the same conclusions as in previous years; i.e., there is no evidence that the radionuclide contamination at Amchitka Island is greater than would be expected from world fallout except for a slight contamination of the Long Shot Mud Pits with tritium.

  1. Light ion production for a future radiobiological facility at CERN: preliminary studies.

    Stafford-Haworth, Joshua; Bellodi, Giulia; Küchler, Detlef; Lombardi, Alessandra; Röhrich, Jörg; Scrivens, Richard


    Recent medical applications of ions such as carbon and helium have proved extremely effective for the treatment of human patients. However, before now a comprehensive study of the effects of different light ions on organic targets has not been completed. There is a strong desire for a dedicated facility which can produce ions in the range of protons to neon in order to perform this study. This paper will present the proposal and preliminary investigations into the production of light ions, and the development of a radiobiological research facility at CERN. The aims of this project will be presented along with the modifications required to the existing linear accelerator (Linac3), and the foreseen facility, including the requirements for an ion source in terms of some of the specification parameters and the flexibility of operation for different ion types. Preliminary results from beam transport simulations will be presented, in addition to some planned tests required to produce some of the required light ions (lithium, boron) to be conducted in collaboration with the Helmholtz-Zentrum für Materialien und Energie, Berlin.

  2. SU-E-T-385: 4D Radiobiology

    Fourkal, E; Hossain, M; Veltchev, I; Ma, C; Meyer, J; Horwitz, E [Fox Chase Cancer Center, Philadelphia, PA (United States); Nahum, A [Clatterbridge Centre for Oncology, Bebington (United Kingdom)


    Purpose: The linear-quadratic model is the most prevalent model for planning dose fractionation in radiation therapy in the low dose per fraction regimens. However for high-dose fractions, used in SRS/SBRT/HDR treatments the LQ model does not yield accurate predictions, due to neglecting the reduction in the number of sublethal lesions as a result of their conversion to lethal lesions with subsequent irradiation. Proper accounting for this reduction in the number of sublethally damaged lesions leads to the dependence of the survival fraction on the temporal structure of the dose. The main objective of this work is to show that the functional dependence of the dose rate on time in each voxel is an important additional factor that can significantly influence the TCP. Methods: Two SBRT lung plans have been used to calculate the TCPs for the same patient. One plan is a 3D conformal plan and the other is an IMRT plan. Both plans are normalized so that 99.5% of PTV volume receives the same prescription dose of 50 Gy in 5 fractions. The dose rate in each individual voxel is calculated as a function of treatment time and subsequently used in the calculation of TCP. Results: The calculated TCPs show that shorter delivery times lead to greater TCP, despite all delivery times being short compared to the repair half-time for sublethal lesions. Furthermore, calculated TCP(IMRT) =0.308 for the IMRT plan is smaller than TCP(3D) =0.425 for 3D conformal, even though it shows greater tumor hot spots and equal PTV coverage. The calculated TCPs are considerably lower compared to those based on the LQ model for which TCP=1 for both plans. Conclusion: The functional dependence of the voxel-by-voxel dose rate on time may be an important factor in predicting the treatment outcome and cannot be neglected in radiobiological modeling.

  3. Technical and harmonic analysis of Carl Czerny op. 299 number 34 etude

    Mehmet Serkan Umuzdas


    Full Text Available In this study, the 34th etude of the book Czerny Op. 299 that is one of the commonly employed books in the piano training was analysed in terms of technique and harmony. The etude was examined in terms of its technical features and contributions to technical development. If an etude is analysed before it is played, time and effort can be amanged much more efficiently. In turn, it may contribute to play the etude or work in accordance with its objectives and to produce outcomes. The aims of this study are to make the students aware of the goals and methods of etudes and to provide them with the suggestions for studying. It is suggested that any etude written with the 2/4 rhythm pattern should be played very vividly and energytically. Any etude written in the octave width of 5.5 is made up of 43 scales in two section. The etude is composed of two sections, each with four sentences and two periods. It also involves 43 scales. Of them, 16 scales are in the first section and the remaining 27 scales are in the second section. The etude has very regular system in terms of harmonic continuity and motives. It has a homogenious pattern in terms of the order of the sentences with half-decsion and those with full-decision.

  4. PENULISAN ETUDE-ETUDE MUSIK TALEMPONG UNGGAN (Sebuah Usaha Pembelajaran Musik Tradisi Berbasis Literatur

    Asri MK


    Full Text Available “Talempong unggan”, a traditional music from Minangkabau community particularly in Unggan, Sumpur Kudus, Sijunjung Regency, West Sumatera Indonesia is classified into genre of “talempong duduak” (rea. Due to its special musical concept and the playing technics, this traditional music is selected as a practising course in the Karawitan Department of Indonesian Institute of Art (ISI Padang Panjang since 1993 till now. In a system of class learning with many students, Talempong Unggan definitely needs supporting methods and learning technics suitable for the course where the students can reach their maximum skills. All the melody of “talempong unggan” that has been made as a material of practice is transcribed to the system of numeric notation and rhythm motive of “gendang” and “aguang” which is written into signs and special notation. All of qualitative data is formulated into finding methods, technics and etude of learning ensamble of Talempong Unggan the traditional music that learned in Karawitan Department of ISI Padang Panjang. Key words: Talempong Unggan, Methods, Technics, Etude

  5. Radiobiological effects of heavy ions and protons. [on cells of mammals, bacteria and viruses

    Ryzhov, N. I.; Vorozhtsova, S. V.; Krasavin, Y. A.; Mashinskaya, T. Y.; Savchenko, N. Y.; Fedorov, B. S.; Khlaponina, V. F.; Shelegedin, V. N.; Gut, L.; Sabo, L.


    Radiobiological effects of heavy ions and protons are studied on cells of mammals, bacteria, viruses and DNA of bacteria. Results show that the dose effect dependence bears an exponential character; the reduction of RBE as LET of particle increases reflects the different character of microdistribution of absorbed energy in biological objects with different levels of biological organization.

  6. A community call for a dedicated radiobiological research facility to support particle beam cancer therapy

    Holzscheiter, Michael H.; Bassler, Niels; Dosanjh, Manjit;


    Recently more than one hundred researchers followed an invitation to a brainstorming meeting on the topic of a future dedicated radio-biological and radio-physical research center. 100 more joint the meeting via webcast. After a day of presentations and discussions it was clear, that an urgent need...

  7. Radiobiological effects of heavy ions and protons. [on cells of mammals, bacteria and viruses

    Ryzhov, N. I.; Vorozhtsova, S. V.; Krasavin, Y. A.; Mashinskaya, T. Y.; Savchenko, N. Y.; Fedorov, B. S.; Khlaponina, V. F.; Shelegedin, V. N.; Gut, L.; Sabo, L.


    Radiobiological effects of heavy ions and protons are studied on cells of mammals, bacteria, viruses and DNA of bacteria. Results show that the dose effect dependence bears an exponential character; the reduction of RBE as LET of particle increases reflects the different character of microdistribution of absorbed energy in biological objects with different levels of biological organization.

  8. Study of the integration of distributed generation systems in the grid: application in micro-grids; Etude de structures d'integration des systemes de generation decentralisee: application aux microreseaux

    Gaztanaga Arantzamendi, H


    The present PhD deals with an original micro-grid concept and its application as a Renewable Energy Source's (RES) grid integration scheme. This micro-grid is composed of RES generators as well as support systems that incorporate additional functionalities in order to improve RES integration into the grid. According to this concept, two practical micro-grid applications have been studied in detail: a residential micro-grid and a wind farm supported by DFACTS systems (STATCOM and DVR). In both applications, the control structures which are implemented at different levels and applied to the different micro-grid elements have been developed, analyzed by means of off-line simulations and finally validated in real-time conditions with physical reduced-scale prototypes. (author)

  9. Fusion of multimodal medical images. Application to dynamic tri dimensional study of vertebral column; Fusion d`images medicales multimodales. Application a l`etude tridimensionnelle dynamique de la colonne vertebrale

    Brunie, L.


    The object of this thesis is to put in correspondence images coming from different ways. The area of application is biomedical imaging, particularly dynamic imaging in three dimensional calculations of spinal cord. The use of computers allows modeling. Then a study of validation by clinical experimentation on spinal cord proves the efficiency of the simulation.

  10. A study of the aptitude of soils under natural conditions to retain radiostrontium; Etude de la vocation des sols en place a la retention du radiostrontium

    Bovard, P.; Grauby, A. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires


    Independently of the theoretical study of the propagation of radioactivity in the soil as a result of submersions or of radioactive rain, the authors have studied directly and practically how this radioactivity can vary in the actual soil. To this end a simple, rapid method has been perfected; it makes it possible to maintain for each soil sample the natural parameters (structure, humidity, etc.) without introducing boundary effects. In the laboratory, after charging the soil samples, part of the study of the propagation of radioactivity is done by autoradiography; finally, as a practical application, the study of an atomic site illustrates the methods described. (author) [French] Independamment de l'etude theorique de la propagation de la radioactivite dans le sol a la suite de submersions ou de pluies radioactives, les auteurs ont etudie directement et pratiquement comment pourrait evoluer cette radioactivite dans les sols en place. Pour cela, une methode simple et rapide a ete mise au point; elle permet de conserver pour chaque echantillon de sol, les parametres naturels (structure, humidite, etc...), sans introduire d'effets de paroi. En laboratoire, apres mise en charge des massifs preleves, une partie de l'etude de la propagation des radioelements est realisee par autoradiographie; enfin, une application pratique, l'etude d'un site atomique, illustre l'expose. (auteur)

  11. Application of stable isotopes to the NMR conformational study of peptides and membrane proteins; Application des isotopes stables a l`etude conformationnelle par RMN de peptides et proteines membranaires

    Neumann, J.M.; Macquaire, F.; Cordier, F.; Musat, G.; Baleux, F. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Biologie Cellulaire et Moleculaire; Huynh-Dinh, T.; Roux, M.; Sanson, A. [Centre National de la Recherche Scientifique (CNRS), 75 - Paris (France)


    The nuclear magnetic resonance spectral analysis of the lipid-peptide complexes generally necessitates isotopic enrichment, specifically or not, of the lipidic or peptidic partner. The isotope labelling depends on the membrane model and the associated NMR techniques: high resolution {sup 1}H NMR of peptides or proteins in the presence of per-deuterated phospholipidic micells, high resolution (micells) or ``solid`` type {sup 2}H NMR of the lipid partner, ``solid`` type NMR ({sup 15}N, {sup 13}C) of the peptide partner in a bi-layer. Application examples are given: utilization of stable isotopes for NMR study of lipopeptide structure and dynamic, of folding-up and functional linking at the annexines membrane interface, and of phospholipid conformation and dynamics in the lipids-ions-peptides interactions. 3 figs.

  12. Determination of a PWR key neutron parameters uncertainties and conformity studies applications; Determination des incertitudes liees aux grandeurs neutroniques d'interet des reacteurs a eau pressurisee a plaques combustible et applications aux etudes de conformite

    Bernard, D


    The aim of this thesis was to evaluate uncertainties of key neutron parameters of slab reactors. Uncertainties sources have many origins, technologic origin for parameters of fabrication and physical origin for nuclear data. First, each contribution of uncertainties is calculated and finally, a factor of uncertainties is associated to key slab parameter like reactivity, isotherm reactivity coefficient, control rod efficiency, power form factor before irradiation and lifetime. This factors of uncertainties were computed by Generalized Perturbations Theory in case of step 0 and by directs calculations in case of irradiation problems. One of neutronic conformity applications was about fabrication and nuclear data targets precision adjustments. Statistic (uncertainties) and deterministic (deviations) approaches were studied. Then neutronics key slab parameters uncertainties were reduced and so nuclear performances were optimised. (author)

  13. Paul Scherrer Institut annual report 1995. Annex II: PSI life sciences and institute for medical radiobiology newsletter 1995

    Blaeuenstein, P.; Gschwend, B. [eds.


    The newsletter presents the 1995 progress report of PSI F2-Department and of the Institute for Medical Radiobiology in the fields of radiation medicine, radiopharmacy and radiation hygiene. figs., tabs., refs.

  14. Synthesis and study of nano-structured cellulose acetate based materials for energy applications; Synthese et etude de materiaux nanostructures a base d'acetate de cellulose pour applications energetiques

    Fischer, F


    Nano-structured materials have unique properties (high exchange areas, containment effect) because of their very low characteristic dimensions. The elaboration way set up in this PhD work consists in applying the classical processes for the preparation of aerogel-like materials (combining sol-gel synthesis and CO{sub 2} supercritical extraction) to cellulosic polymers. This work is divided in four parts: a literature review, the presentation and the study of the chemical synthesis that leads to cellulose acetate-based aerogel, the characterizations (chemical, structural and thermal) of the elaborated nano-materials, and finally the study of the first carbons that were obtained after pyrolysis of the organic matrix. The formulations and the sol-gel protocol lead to chemical gels by crosslinking cellulose acetate using a poly-functional iso-cyanate. The dry materials obtained after solvent extraction with supercritical CO{sub 2} are nano-structured and mainly meso-porous. Correlations between chemical synthesis parameters (reagent concentrations, crosslinking rate and degree of polymerisation) and porous properties (density, porosity, pore size distribution) were highlighted thanks to structural characterizations. An ultra-porous reference aerogel, with a density equals to 0,245{sup -3} together with a meso-porous volume of 3,40 cm{sup 3}.g{sup -1} was elaborated. Once in granular shape, this material has a thermal conductivity of 0,029 W.m{sup -1}.K{sup -1}. In addition, carbon materials produced after pyrolysis of the organic matrix and after grinding are nano-structured and nano-porous, even if important structural modifications have occurred during the carbonization process. The elaborated materials are evaluated for applications in relation with energy such as thermal insulation (organic aerogels) but also for energy conversion and storage through electrochemical way (carbon aerogels). (author)

  15. Study of optically stimulated luminescence (OSL) for radiation detection. Application to an optical fibre {gamma}-radiation sensor; Etude de la luminescence stimulee optiquement (OSL) pour la detection de rayonnements: application a un capteur a fibre optique de rayonnement {gamma}

    Roy, O. [CEA Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Electronique et d`Instrumentation Nucleaire]|[Paris-7 Univ., 75 (France)


    This work shows up the usefulness of the Optically Stimulated Luminescence (OSL) to resolve radioprotection problems. We study the use of OSL as a gamma dosimetric technique with respect to the ALARA`s concept (As Low As Reasonably Achievable). A new approach based on optical fibers and luminescent materials showing OSL properties (closely related to Thermoluminescence phenomena) is presented in order to improve the remote real time dosimetry monitoring. Like thermoluminescent materials (TLD), OSL materials can trap charges under an irradiation (UV, X, {gamma},...). Instead of heating, the charges trapped are released by light stimulation and produce a visible luminescence which amount is proportional to trap the `data stored` left by irradiation, enabling the dose measurement. The OSL phenomenon offers the same advantages as TLD plus the interesting possibility of a remote optical stimulation. The end-user objective deals with the development of a {gamma}-radiation Optical FIber Sensor (OFS) for dose measurement which can offer new functionalities based on OSL materials coupled with an optical fiber. Rare earth doped Alkaline Earth Sulphides (AES), BAFX:EU{sup 2+} (X = Cl, Br, I) and halogen alkaline have been studied (crystalline form, synthesis techniques, influence of dopants and color centers). Their characteristics are presented and extensively discussed. A specific experimental set-up to characterise various OSL phosphors has been developed. It allows the study of sensitivity, linearity, time decay behaviour of OSL signal and zeroing time. A joint study of OSL and TL has shown the technical limitations as well as the thermal fading and the origin of the long zeroing time. An Optical Fiber Sensor (OFS) based on OSL and using MgS:Sm has been developed for practical applications on nuclear fields. Its specifications are presented and discussed, moreover improvements are proposed. (author) 320 refs.

  16. Study of hydrogenated amorphous silicon devices under intense electric field: application to nuclear detection; Etude de dispositifs electroniques en silicium amorphe hydrogene sous fort champ electrique: application a la detection nucleaire

    Ilie, A. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Direction des Technologies Avancees]|[Paris-11 Univ., 91 - Orsay (France)


    The goal of this work was the study, development and optimization of hydrogenated amorphous silicon (a-Si:H) devices for use in detection of ionizing radiation. Thick p-i-n devices, capable of withstanding large electric fields (up to 10{sup 6} V/cm) with small currents (nA/cm{sup 2}), were developed. To decrease fabrication time, films were made using the `He diluted` PECVD process and compared to standard a-Si:H films. Aspects connected to specific detector applications as well as to the fundamental physics of a-Si:H were considered: the internal electric field technique, in which the depletion charge was measured as a function of the applied bias voltage; study of the leakage current of p-i-n devices permitted us to demonstrate different regimes: depletion, field-enhanced thermal generation and electronic injection across the p layer. The effect of the electric field on the thermal generation of the carriers was studied considering the Poole-Frenkel and tunneling mechanisms. A model was developed taking under consideration the statistics of the correlated states and electron-phonon coupling. The results suggest that mechanisms not included in the `standard model` of a Si:h need to be considered, such as defect relaxation, a filed-dependent mobility edge etc...; a new metastable phenomenon, induced by prolonged exposure to a strong electric field, was observed and studied. It is characterized by marked decrease of the leakage current and the detector noise, and increase in the breakdown voltage, as well as an improvement of carrier collection efficiency. This forming process appears to be principally due to an activation of the dopants in the p layer; finally, the capacity of thick p-i-n a Si:H devices to detect ionizing radiation has been evaluated. We show that it is possible, with 20-50 micron thick p-i-n devices, to detect the full spectrum of alpha and beta particles. With an appropriate converter, neutron detection then becomes possible. (author). 137 refs.

  17. Multi-scale approach for the study of the behaviour of multiphase systems. Application to non saturated porous media; Approche multi-echelle pour l'etude du comportement des systemes polyphasiques. Application aux milieux poreux non satures

    Xu, Y.


    In this thesis, the modeling of the behaviour of the unsaturated porous media, whose solid phase is composed of elastic linear material, is studied in the framework of micro-mechanics. Firstly, we recall some classical results on the homogenization of the homogeneous materials in the case where the macroscopic behaviour of the materials is elastic linear (chapter 1). This part concerning essentially the bibliography, we present also the applications of the micro-mechanical approach to the drying porous media and the saturated ones. In order to study the unsaturated case, it is necessary to know the distribution of the fluids in the porous space. The methods permitting to determine the equilibrium positions of a capillary interface inside of a porous medium and to study their stability are presented in the second chapter of this thesis, particularly in the case where there is no material exchange between the fluid phases. Then we use the 'classical' linear homogenization approach to study the mechanic behaviour for a porous medium saturated by two fluid phases (chapter 3). The results obtained are applied to estimate the drying strains, in the case where the subjected stress and the temperature remain constant, with taking into account the influence of the morphology characters of the porous space and the domains occupied by the fluid phases. In the fourth chapter, the modeling of the behaviour of a medium containing unsaturated meso-cracks is studied by considering the coupling between the capillary forces and the geometric changes of the cracks. By an example of drying, we show that, in the case where the cracks are very flat, the macroscopic behaviour accounting for the non-linearity differs significantly from the results of the linear approach. The thesis is finished by an examination of a granular material behaviour. To this end, we use a numerical approach based on the periodic hypothesis of the materials studied. All results obtained in this thesis

  18. Effects of radiobiological uncertainty on shield design for a 60-day lunar mission

    Wilson, John W.; Nealy, John E.; Schimmerling, Walter


    Some consequences of uncertainties in radiobiological risk due to galactic cosmic ray exposure are analyzed to determine their effect on engineering designs for a first lunar outpost - a 60-day mission. Quantitative estimates of shield mass requirements as a function of a radiobiological uncertainty factor are given for a simplified vehicle structure. The additional shield mass required for compensation is calculated as a function of the uncertainty in galactic cosmic ray exposure, and this mass is found to be as large as a factor of 3 for a lunar transfer vehicle. The additional cost resulting from this mass is also calculated. These cost estimates are then used to exemplify the cost-effectiveness of research.

  19. Ill-posed problem and regularization in reconstruction of radiobiological parameters from serial tumor imaging data

    Chvetsov, Alevei V.; Sandison, George A.; Schwartz, Jeffrey L.; Rengan, Ramesh


    The main objective of this article is to improve the stability of reconstruction algorithms for estimation of radiobiological parameters using serial tumor imaging data acquired during radiation therapy. Serial images of tumor response to radiation therapy represent a complex summation of several exponential processes as treatment induced cell inactivation, tumor growth rates, and the rate of cell loss. Accurate assessment of treatment response would require separation of these processes because they define radiobiological determinants of treatment response and, correspondingly, tumor control probability. However, the estimation of radiobiological parameters using imaging data can be considered an inverse ill-posed problem because a sum of several exponentials would produce the Fredholm integral equation of the first kind which is ill posed. Therefore, the stability of reconstruction of radiobiological parameters presents a problem even for the simplest models of tumor response. To study stability of the parameter reconstruction problem, we used a set of serial CT imaging data for head and neck cancer and a simplest case of a two-level cell population model of tumor response. Inverse reconstruction was performed using a simulated annealing algorithm to minimize a least squared objective function. Results show that the reconstructed values of cell surviving fractions and cell doubling time exhibit significant nonphysical fluctuations if no stabilization algorithms are applied. However, after applying a stabilization algorithm based on variational regularization, the reconstruction produces statistical distributions for survival fractions and doubling time that are comparable to published in vitro data. This algorithm is an advance over our previous work where only cell surviving fractions were reconstructed. We conclude that variational regularization allows for an increase in the number of free parameters in our model which enables development of more

  20. The impact of modeling nuclear fragmentation on delivered dose and radiobiology in ion therapy.

    Lühr, Armin; Hansen, David C; Teiwes, Ricky; Sobolevsky, Nikolai; Jäkel, Oliver; Bassler, Niels


    The importance of nuclear interactions for ion therapy arises from the influence of the particle spectrum on, first, radiobiology and therefore also on treatment planning, second, the accuracy of measuring dose and, third, the delivered dose distribution. This study tries to determine the qualitative as well as the quantitative influence of the modeling of inelastic nuclear interactions on ion therapy. Thereby, three key disciplines are investigated, namely dose delivery, dose assessment and radiobiology. In order to perform a quantitative analysis, a relative comparison between six different descriptions of nuclear interactions is carried out for carbon ions. The particle transport is simulated with the Monte Carlo code SHIELD-HIT10A while dose planning and radiobiology are covered by the analytic treatment planning program for particles TRiP, which determines the relative biological effectiveness (RBE) with the local effect model. The obtained results show that the physical dose distribution can in principle be significantly influenced by the modeling of fragmentation (about 10% for a 20% change in all inelastic nuclear cross sections for a target volume ranging from 15 to 25 cm). While the impact of nuclear fragmentation on stopping power ratios can be neglected, the fluence correction factor may be influenced by the applied nuclear models. In contrast to the results for the physical dose, the variation of the RBE is only small (about 1% for a 20% change in all inelastic nuclear cross sections) suggesting a relatively weak dependence of radiobiology on the detailed composition of the particle energy spectrum of the mixed radiation field. Also, no significant change (about 0.2 mm) of the lateral penumbra of the RBE-weighted dose is observed.

  1. Prognostic value of radiobiological hypoxia during fractionated irradiation for local tumor control.

    Zips, Daniel; Böke, Simon; Kroeber, Theresa; Meinzer, Andreas; Brüchner, Kerstin; Thames, Howard D; Baumann, Michael; Yaromina, Ala


    Previous experiments showed that the fraction of radiobiologically hypoxic tumor cells (rHF) in un-treated tumors did not accurately predict local tumor control after fractionated irradiation. Thus, the prognostic value of rHF determined during fractionated irradiation was investigated. Six human squamous cell carcinoma lines were transplanted into nude mice and then irradiated with 15 fractions over 3 weeks. Thereafter, single dose irradiation under normal and clamped blood flow was given. Local tumor control rates were used to calculate the rHF and the TCD₅₀, i.e., the radiation dose necessary to control 50% of the tumors, after single dose irradiation. These values were compared with the in parallel determined TCD₅₀ after 30 fractions in 6 weeks. The rHF after 15 fractions varied between 28% and 100%. No correlation was found with the TCD₅₀ after 30 fractions in 6 weeks. Single dose top-up TCD₅₀ under ambient and clamp conditions after 15 fractions significantly correlated with TCD₅₀ after 30 fractions in 6 weeks. rHF after 15 fractions is not a prognostic parameter for the outcome after fractionated irradiation. In contrast, the radiobiological parameters number of tumor stem cells, intrinsic radiosensitivity, and number of radiobiologically hypoxic tumor cells appear promising to predict outcome after fractionated irradiation.

  2. Prognostic value of radiobiological hypoxia during fractionated irradiation for local tumor control

    Zips, Daniel; Boeke, Simon; Kroeber, Theresa; Meinzer, Andreas; Bruechner, Kerstin; Yaromina, Ala [OncoRay National Center for Radiation Research in Oncology, Dresden (Germany). Dept. of Radiation Oncology; Thames, Howard D. [Texas Univ., M.D. Anderson Cancer Center, Houston, TX (United States). Div. of Quantitative Sciences; Baumann, Michael [OncoRay National Center for Radiation Research in Oncology, Dresden (Germany). Dept. of Radiation Oncology; Universitaetsklinikum Dresden (Germany). Experimental Center


    Background and Purpose: Previous experiments showed that the fraction of radiobiologically hypoxic tumor cells (rHF) in untreated tumors did not accurately predict local tumor control after fractionated irradiation. Thus, the prognostic value of rHF determined during fractionated irradiation was investigated. Materials and Methods: Six human squamous cell carcinoma lines were transplanted into nude mice and then irradiated with 15 fractions over 3 weeks. Thereafter, single dose irradiation under normal and clamped blood flow was given. Local tumor control rates were used to calculate the rHF and the TCD{sub 50}, i.e., the radiation dose necessary to control 50% of the tumors, after single dose irradiation. These values were compared with the in parallel determined TCD{sub 50} after 30 fractions in 6 weeks. Results: The rHF after 15 fractions varied between 28% and 100%. No correlation was found with the TCD{sub 50} after 30 fractions in 6 weeks. Single dose top-up TCD{sub 50} under ambient and clamp conditions after 15 fractions significantly correlated with TCD{sub 50} after 30 fractions in 6 weeks. Conclusion: rHF after 15 fractions is not a prognostic parameter for the outcome after fractionated irradiation. In contrast, the radiobiological parameters number of tumor stem cells, intrinsic radiosensitivity, and number of radiobiologically hypoxic tumor cells appear promising to predict outcome after fractionated irradiation. (orig.)

  3. Fast neutrons set the pace. [Radiobiological investigations with fast neutrons at the CSIR cyclotron in Pretoria

    Hough, J.H.; Slabbert, J.P. (Council for Scientific and Industrial Research, Pretoria (South Africa). National Accelerator Centre)


    Radiobiological investigations with fast neutrons have been initiated at the CSIR cyclotron in Pretoria. It was proposed some years ago to create a neutron therapy facility using the CSIR cyclotron. Neutrons are classified as high linear energy transfer (LET) particles. Biological damage occurring in tissue is a direct function of the LET of the incident radiation. To quantify the biological effects of different types of radiation on mammalian cells, several procedures and concepts have evolved from radiobiological research. Probably the most significant laboratory techniques developed, were the derivation of cell survival curves which are obtained by determining the number of cell colonies that have survived a certain radiation dose. A semi-logarithmic plot of surviving fraction versus the absorbed dose yields the survival curve. Dose modifying factors such as the relative biological effectiveness (RBE) of the radiation can be quantified in terms of this relationship. A radiobiological programme has to be undertaken before patients can receive neutron therapy at the CSIR cyclotron. The article is a discussion of this programme.

  4. Comparison of treatment plans: a retrospective study by the method of radiobiological evaluation

    Puzhakkal, Niyas; Kallikuzhiyil Kochunny, Abdullah; Manthala Padannayil, Noufal; Singh, Navin; Elavan Chalil, Jumanath; Kulangarakath Umer, Jamshad


    There are many situations in radiotherapy where multiple treatment plans need to be compared for selection of an optimal plan. In this study we performed the radiobiological method of plan evaluation to verify the treatment plan comparison procedure of our clinical practice. We estimated and correlated various radiobiological dose indices with physical dose metrics for a total of 30 patients representing typical cases of head and neck, prostate and brain tumors. Three sets of plans along with a clinically approved plan (final plan) treated by either Intensity Modulated Radiation Therapy (IMRT) or Rapid Arc (RA) techniques were considered. The study yielded improved target coverage for final plans, however, no appreciable differences in doses and the complication probabilities of organs at risk were noticed. Even though all four plans showed adequate dose distributions, from dosimetric point of view, the final plan had more acceptable dose distribution. The estimated biological outcome and dose volume histogram data showed least differences between plans for IMRT when compared to RA. Our retrospective study based on 120 plans, validated the radiobiological method of plan evaluation. The tumor cure or normal tissue complication probabilities were found to be correlated with the corresponding physical dose indices.

  5. Nuclear study of Melusine; Etude nucleaire de Melusine

    Cherot, J. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires


    In this report are reviewed - with respect to starting of experiments - the main nuclear characteristics of a 20 per cent enriched uranium lattice, with light water as moderator and reflector. The reactor is to operate at 1 MW. 1) Study of various critical masses. 2) Control. Effectiveness of cadmium. Control rods and of a stainless steel regulating rod. 3) Study of the effect on reactivity of disturbances in the core center. 4) Study of xenon and samarium poisoning. 5) Temperature factor. 6) Heat exchanges in a fuel element. (author) [French] On etudie, dans ce rapport, les principales proprietes nucleaires d'un reseau a uranium enrichi (20 pour cent), dont le moderateur et le reflecteur sont l'eau legere en vue des experiences de demarrage. Ce reacteur devra fonctionner a 1 MW. 1) Etude de diverses masses critiques. 2) Controle. Efficacite des barres de controle en cadmium et d'une barre de reglage en acier inoxydable. 3) Etude de l'effet sur la reactivite de perturbation au centre du coeur. 4) Etude de l'empoisonnement xenon et samarium. 5) Coefficient de temperature. 6) Echanges thermiques dans un element. (auteur)

  6. Estimation of a Self-Consistent Set of Radiobiological Parameters From Hypofractionated Versus Standard Radiation Therapy of Prostate Cancer

    Pedicini, Piernicola, E-mail: [Service of Medical Physics, Istituto di Ricovero e Cura a Carattere Scientifico Centro di Riferimento Oncologico della Basilicata, Rionero in Vulture (Italy); Strigari, Lidia [Laboratory of Medical Physics and Expert Systems, Istituto Nazionale Tumori Regina Elena, Rome (Italy); Benassi, Marcello [Service of Medical Physics, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori, Meldola (Italy)


    Purpose: To determine a self-consistent set of radiobiological parameters in prostate cancer. Methods and Materials: A method to estimate intrinsic radiosensitivity (α), fractionation sensitivity (α/β), repopulation doubling time, number of clonogens, and kick-off time for accelerated repopulation of prostate cancer has been developed. Based on the generalized linear-quadratic model and without assuming the isoeffective hypothesis, the potential applications of the method were investigated using the clinical outcome of biochemical relapse-free survival recently reviewed in the literature. The strengths and limitations of the method, regarding the fitted parameters and 95% confidence intervals (CIs), are also discussed. Results: Our best estimate of α/β is 2.96 Gy (95% CI 2.41-3.53 Gy). The corresponding α value is 0.16 Gy{sup −1} (95% CI 0.14-0.18 Gy{sup −1}), which is compatible with a realistic number of clonogens: 6.5 × 10{sup 6} (95% CI 1.5 × 10{sup 6}-2.1 × 10{sup 7}). The estimated cell doubling time is 5.1 days (95% CI 4.2-7.2 days), very low if compared with that reported in the literature. This corresponds to the dose required to offset the repopulation occurring in 1 day of 0.52 Gy/d (95% CI 0.32-0.68 Gy/d). However, a long kick-off time of 31 days (95% CI 22-41 days) from the start of radiation therapy was found. Conclusion: The proposed analytic/graphic method has allowed the fitting of clinical data, providing a self-consistent set of radiobiological parameters for prostate cancer. With our analysis we confirm a low value for α/β with a correspondingly high value of intrinsic radiosensitivity, a realistic average number of clonogens, a long kick-off time for accelerated repopulation, and a surprisingly fast repopulation that suggests the involvement of subpopulations of specifically tumorigenic stem cells during continuing radiation therapy.

  7. Hypo-fractionated treatment in radiotherapy: radio-biological models Tcp and NTCP; Tratamiento hipofraccionado en radioterapia: modelos radiobiologicos TCP y NTCP

    Astudillo V, A. J.; Mitsoura, E. [Universidad Autonoma del Estado de Mexico, Facultad de Medicina, Paseo Tollocan s/n, 50180 Toluca, Estado de Mexico (Mexico); Paredes G, L. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Resendiz G, G., E-mail: [Hospital Medica Sur, Departamento de Radioterapia, Puente de Piedra 150, Col. Toriello Guerra, 14050 Mexico D. F. (Mexico)


    At the present time the breast cancer in Mexico has the first place of incidence of the malignant neoplasia s in the women, and represents 11.34% of all the cancer cases. On the other hand, the treatments for cancer by means of ionizing radiations have been dominated under the approaches of the medical radio-oncologists which have been based on test and error by many years. The radio-biological models, as the Tcp, NTCP and dosimetric variables, for their clinical application in the conventional radiotherapy with hypo-fractionation have as purpose predicting personalized treatment plans that they present most probability of tumor control and minor probability of late reactions, becoming this way support tools in the decisions taking for the patient treatments planning of Medical Physicists and Radio-oncologists. (Author)

  8. Laser-driven particle acceleration towards radiobiology and medicine


    This book deals with the new method of laser-driven acceleration for application to radiation biophysics and medicine. It provides multidisciplinary contributions from world leading scientist in order to assess the state of the art of innovative tools for radiation biology research and medical applications of ionizing radiation. The book contains insightful contributions on highly topical aspects of spatio-temporal radiation biophysics, evolving over several orders of magnitude, typically from femtosecond and sub-micrometer scales. Particular attention is devoted to the emerging technology of laser-driven particle accelerators and their applicatio to spatio-temporal radiation biology and medical physics, customization of non-conventional and selective radiotherapy and optimized radioprotection protocols.

  9. Development of a compact laser-produced plasma soft X-ray source for radiobiology experiments

    Adjei, Daniel, E-mail: [Institute of Optoelectronics, Military University of Technology, 2, Kaliskiego Str., 00-908 Warsaw (Poland); Radiation Protection Institute, Ghana Atomic Energy Commission, P.O. Box LG 80, Legon, Accra (Ghana); Ayele, Mesfin Getachew; Wachulak, Przemyslaw; Bartnik, Andrzej; Wegrzynski, Łukasz; Fiedorowicz, Henryk [Institute of Optoelectronics, Military University of Technology, 2, Kaliskiego Str., 00-908 Warsaw (Poland); Vyšín, Luděk [Institute of Physics, Czech Academy of Sciences, Na Slovance 2, 182 21 Prague 8 (Czech Republic); Faculty of Nuclear Sciences and Engineering Physics, Czech Technical University in Prague, Břehová 7, 115 19 Prague 1 (Czech Republic); Wiechec, Anna; Lekki, Janusz; Kwiatek, Wojciech M. [Institute of Nuclear Physics, Polish Academy of Sciences, 152, Radzikowskiego Str., 31-342 Cracow (Poland); Pina, Ladislav [Faculty of Nuclear Sciences and Engineering Physics, Czech Technical University in Prague, Břehová 7, 115 19 Prague 1 (Czech Republic); Davídková, Marie [Institute of Nuclear Physics, Czech Academy of Sciences, Řež (Czech Republic); Juha, Libor [Institute of Physics, Czech Academy of Sciences, Na Slovance 2, 182 21 Prague 8 (Czech Republic)


    A desk-top laser-produced plasma (LPP) source of soft X-rays (SXR) has been developed for radiobiology research. The source is based on a double-stream gas puff target, irradiated with the focused beam of a commercial Nd:YAG laser. The source has been optimized to get a maximum photon emission from LPP in the X-ray “water window” spectral wavelength range from 2.3 nm (i.e., an absorption edge of oxygen) to 4.4 nm (i.e., an absorption edge of carbon) (280–540 eV in photon energy units) by using argon gas-puff target and spectral filtering by free-standing thin foils. The present source delivers nanosecond pulses of soft X-rays at a fluence of about 4.2 × 10{sup 3} photons/μm{sup 2}/pulse on a sample placed inside the vacuum chamber. In this paper, the source design, radiation output characterization measurements and initial irradiation experiments are described. The source can be useful in addressing observations related to biomolecular, cellular and organisms’ sensitivity to pulsed radiation in the “water window”, where carbon atoms absorb X-rays more strongly than the oxygen, mostly present in water. The combination of the SXR source and the radiobiology irradiation layout, reported in this article, make possible a systematic investigation of relationships between direct and indirect action of ionizing radiation, an increase of a local dose in carbon-rich compartments of the cell (e.g., lipid membranes), an experimental estimation of a particular role of the Auger effect (in particular in carbon atoms) in the damage to biological systems, and the study of ionization/excitation-density (LET – Linear Energy Transfer) and dose-rate effects in radiobiology.

  10. Mixed-field GCR Simulations for Radiobiological Research Using Ground Based Accelerators

    Kim, Myung-Hee Y.; Rusek, Adam; Cucinotta, Francis A.


    Space radiation is comprised of a large number of particle types and energies, which have differential ionization power from high energy protons to high charge and energy (HZE) particles and secondary neutrons produced by galactic cosmic rays (GCR). Ground based accelerators such as the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL) are used to simulate space radiation for radiobiology research and dosimetry, electronics parts, and shielding testing using mono-energetic beams for single ion species. As a tool to support research on new risk assessment models, we have developed a stochastic model of heavy ion beams and space radiation effects, the GCR Event-based Risk Model computer code (GERMcode). For radiobiological research on mixed-field space radiation, a new GCR simulator at NSRL is proposed. The NSRL-GCR simulator, which implements the rapid switching mode and the higher energy beam extraction to 1.5 GeV/u, can integrate multiple ions into a single simulation to create GCR Z-spectrum in major energy bins. After considering the GCR environment and energy limitations of NSRL, a GCR reference field is proposed after extensive simulation studies using the GERMcode. The GCR reference field is shown to reproduce the Z and LET spectra of GCR behind shielding within 20% accuracy compared to simulated full GCR environments behind shielding. A major challenge for space radiobiology research is to consider chronic GCR exposure of up to 3-years in relation to simulations with cell and animal models of human risks. We discuss possible approaches to map important biological time scales in experimental models using ground-based simulation with extended exposure of up to a few weeks and fractionation approaches at a GCR simulator.

  11. Issues for Simulation of Galactic Cosmic Ray Exposures for Radiobiological Research at Ground Based Accelerators

    Myung-Hee Y Kim


    Full Text Available For research on the health risks of galactic cosmic rays (GCR ground-based accelerators have been used for radiobiology research with mono-energetic beams of single high charge, Z and energy, E (HZE particles. In this paper we consider the pros and cons of a GCR reference field at a particle accelerator. At the NASA Space Radiation Laboratory (NSRL we have proposed a GCR simulator, which implements a new rapid switching mode and higher energy beam extraction to 1.5 GeV/u, in order to integrate multiple ions into a single simulation within hours or longer for chronic exposures. After considering the GCR environment and energy limitations of NSRL, we performed extensive simulation studies using the stochastic transport code, GERMcode (GCR Event Risk Model to define a GCR reference field using 9 HZE particle beam-energy combinations each with a unique absorber thickness to provide fragmentation and 10 or more energies of proton and 4He beams. The reference field is shown to well represent the charge dependence of GCR dose in several energy bins behind shielding compared to a simulated GCR environment. However a more significant challenge for space radiobiology research is to consider chronic GCR exposure of up to 3 years in relation to simulations with animal models of human risks. We discuss issues in approaches to map important biological time scales in experimental models using ground-based simulation with extended exposure of up to a few weeks using chronic or fractionation exposures. A kinetics model of HZE particle hit probabilities suggests that experimental simulations of several weeks will be needed to avoid high fluence rate artifacts, which places limitations on the experiments to be performed. Ultimately risk estimates are limited by theoretical understanding, and focus on improving understanding of mechanisms and development of experimental models to improve this understanding should remain the highest priority for space radiobiology

  12. Radiobiological Determination of Dose Escalation and Normal Tissue Toxicity in Definitive Chemoradiation Therapy for Esophageal Cancer

    Warren, Samantha, E-mail: [Department of Oncology, Gray Institute of Radiation Oncology and Biology, University of Oxford, Oxford (United Kingdom); Partridge, Mike [Department of Oncology, Gray Institute of Radiation Oncology and Biology, University of Oxford, Oxford (United Kingdom); Carrington, Rhys [Velindre Cancer Centre, Velindre Hospital, Cardiff (United Kingdom); Hurt, Chris [Wales Cancer Trials Unit, School of Medicine, Heath Park, Cardiff (United Kingdom); Crosby, Thomas [Velindre Cancer Centre, Velindre Hospital, Cardiff (United Kingdom); Hawkins, Maria A. [Department of Oncology, Gray Institute of Radiation Oncology and Biology, University of Oxford, Oxford (United Kingdom)


    Purpose: This study investigated the trade-off in tumor coverage and organ-at-risk sparing when applying dose escalation for concurrent chemoradiation therapy (CRT) of mid-esophageal cancer, using radiobiological modeling to estimate local control and normal tissue toxicity. Methods and Materials: Twenty-one patients with mid-esophageal cancer were selected from the SCOPE1 database (International Standard Randomised Controlled Trials number 47718479), with a mean planning target volume (PTV) of 327 cm{sup 3}. A boost volume, PTV2 (GTV + 0.5 cm margin), was created. Radiobiological modeling of tumor control probability (TCP) estimated the dose required for a clinically significant (+20%) increase in local control as 62.5 Gy/25 fractions. A RapidArc (RA) plan with a simultaneously integrated boost (SIB) to PTV2 (RA{sub 62.5}) was compared to a standard dose plan of 50 Gy/25 fractions (RA{sub 50}). Dose-volume metrics and estimates of normal tissue complication probability (NTCP) for heart and lungs were compared. Results: Clinically acceptable dose escalation was feasible for 16 of 21 patients, with significant gains (>18%) in tumor control from 38.2% (RA{sub 50}) to 56.3% (RA{sub 62.5}), and only a small increase in predicted toxicity: median heart NTCP 4.4% (RA{sub 50}) versus 5.6% (RA{sub 62.5}) P<.001 and median lung NTCP 6.5% (RA{sub 50}) versus 7.5% (RA{sub 62.5}) P<.001. Conclusions: Dose escalation to the GTV to improve local control is possible when overlap between PTV and organ-at-risk (<8% heart volume and <2.5% lung volume overlap for this study) generates only negligible increase in lung or heart toxicity. These predictions from radiobiological modeling should be tested in future clinical trials.

  13. Development of a compact laser-produced plasma soft X-ray source for radiobiology experiments

    Adjei, Daniel; Ayele, Mesfin Getachew; Wachulak, Przemyslaw; Bartnik, Andrzej; Wegrzynski, Łukasz; Fiedorowicz, Henryk; Vyšín, Luděk; Wiechec, Anna; Lekki, Janusz; Kwiatek, Wojciech M.; Pina, Ladislav; Davídková, Marie; Juha, Libor


    A desk-top laser-produced plasma (LPP) source of soft X-rays (SXR) has been developed for radiobiology research. The source is based on a double-stream gas puff target, irradiated with the focused beam of a commercial Nd:YAG laser. The source has been optimized to get a maximum photon emission from LPP in the X-ray "water window" spectral wavelength range from 2.3 nm (i.e., an absorption edge of oxygen) to 4.4 nm (i.e., an absorption edge of carbon) (280-540 eV in photon energy units) by using argon gas-puff target and spectral filtering by free-standing thin foils. The present source delivers nanosecond pulses of soft X-rays at a fluence of about 4.2 × 103 photons/μm2/pulse on a sample placed inside the vacuum chamber. In this paper, the source design, radiation output characterization measurements and initial irradiation experiments are described. The source can be useful in addressing observations related to biomolecular, cellular and organisms' sensitivity to pulsed radiation in the "water window", where carbon atoms absorb X-rays more strongly than the oxygen, mostly present in water. The combination of the SXR source and the radiobiology irradiation layout, reported in this article, make possible a systematic investigation of relationships between direct and indirect action of ionizing radiation, an increase of a local dose in carbon-rich compartments of the cell (e.g., lipid membranes), an experimental estimation of a particular role of the Auger effect (in particular in carbon atoms) in the damage to biological systems, and the study of ionization/excitation-density (LET - Linear Energy Transfer) and dose-rate effects in radiobiology.

  14. The new hybrid thermal neutron facility at TAPIRO reactor for BNCT radiobiological experiments.

    Esposito, J; Rosi, G; Agosteo, S


    A new thermal neutron irradiation facility, devoted to carry out both dosimetric and radiobiological studies on boron carriers, which are being developed in the framework of INFN BNCT project, has been installed at the ENEA Casaccia TAPIRO research fast reactor. The thermal column, based on an original, hybrid, neutron spectrum shifter configuration, has been recently become operative. In spite of its low power (5 kW), the new facility is able to provide a high thermal neutron flux level, uniformly distributed inside the irradiation cavity, with a quite low gamma background. The main features and preliminary benchmark measurements of the Beam-shaping assembly are here presented and discussed.

  15. Experimental radiotherapy and clinical radiobiology. Vol. 22. Proceedings; Experimentelle Strahlentherapie und Klinische Strahlenbiologie. Bd. 25. Proceedings

    Baumann, Michael; Krause, Mechthild [Universitaetsklinikum Technische Univ. Dresden (Germany). Klinik und Poliklinik fuer Strahlentherapie und Radiologie; Cordes, Nils [Universitaetsklinikum Technische Univ. Dresden (Germany). OncoRay - Nationales Zentrum fuer Strahlenforschung in der Radioonkologie; Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany); Petersen, Cordula [Universitaetsklinikum Hamburg-Eppendorf, Hamburg (Germany). Klinik und Poliklinik fuer Strahlentherapie und Radioonkologie; Rodemann, H. Peter [Universitaetsklinikum Tuebingen (Germany). Sektion fuer Strahlenbiologie; Rothkamm, Kai [Universitaetsklinikum Hamburg-Eppendorf, Hamburg (Germany). Lab. fuer Strahlentherapie und Experimentelle Radioonkologie; Zips, Daniel (ed.) [Tuebingen Univ. (Germany). Universitaetsklinik fuer Radioonkologie


    The proceedings of the 25th symposium on experimental radiotherapy and clinical radiobiology include papers on the following issues: radiotherapy individualization based on imaging; pre-clinic imaging and new experimental methods; methods and models, micromilieu and metabolism, combined therapy; secondary tumors following radiotherapy; radiogenic effects in normal tissue; resistance mechanism of tumors and normal tissue; personalized radio-oncology - which biological data are needed; pre-clinic and personalized radio-oncology; biomarkers - pre-clinic and translational; translational examinations for personalized radio-oncology.

  16. Experimental radiotherapy and clinical radiobiology. Vol. 18. Proceedings; Experimentelle Strahlentherapie und Klinische Strahlenbiologie. Bd. 18. Proceedings

    Baumann, Michael; Dahm-Daphi, Jochen; Dikomey, Ekkehard; Petersen, Cordula; Rodemann, H. Peter; Zips, Daniel (eds.)


    The proceedings on experimental radiotherapy and clinical radiobiology contain two review articles (prediction of normal tissue reactions after radiotherapy, ?H2AX foci as a marker for DNA double-strand breaks) and 34 contributions to the following topics: Hypoxia and molecular mechanisms of radiation resistance; biological imaging of the tumor micromilieu; DNA repair, genomic instability and carcerogenesis; molecular factors of radiation resistance; actual controversial discussion on possible irradiation caused metastasis risk enhancement; EGFR inhibition and irradiation; biology of experimental radiation/ normal tissue toxicity.

  17. Tcp and NTCP radiobiological models: conventional and hypo fractionated treatments in radiotherapy

    Astudillo V, A.; Paredes G, L. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico); Resendiz G, G.; Posadas V, A. [Hospital Angeles Lomas, Av. Vialidad de la Barranca s/n, Col. Valle de las Palmas, 52763 Huixquilucan de Degallado, Estado de Mexico (Mexico); Mitsoura, E. [Universidad Autonoma del Estado de Mexico, Facultad de Medicina, Paseo Tollocan, Esq. Jesus Carranza s/n, Col. Moderna de la Cruz, 50180 Toluca, Estado de Mexico (Mexico); Rodriguez L, A.; Flores C, J. M., E-mail: [Hospital Medica Sur, Puente de Piedra 150, Col. Toriello Guerra, 14050 Tlalpan, Mexico D. F. (Mexico)


    The hypo and conventional fractionated schedules performance were compared in terms of the tumor control and the normal tissue complications. From the records of ten patients, treated for adenocarcinoma and without mastectomy, the dose-volume histogram was used. Using radiobiological models the probabilities for tumor control and normal tissue complications were calculated. For both schedules the tumor control was approximately the same. However, the damage in the normal tissue was larger in conventional fractionated schedule. This is important because patients assistance time to their fractions (15 fractions/25 fractions) can be optimized. Thus, the hypo fractionated schedule has suitable characteristics to be implemented. (Author)

  18. Experimental radiotherapy and clinical radiobiology. Vol. 22. Proceedings; Experimentelle Strahlentherapie und Klinische Strahlenbiologie. Bd. 22. Proceedings

    Baumann, Michael; Cordes, Nils; Dikomey, Ekkehard; Krause, Mechthild; Petersen, Cordula; Rodemannn, H. Peter; Zips, Daniel (eds.)


    The proceedings of the 22th Symposium on experimental radiotherapy and clinical radiotherapy contain lectures and poster on the following issues: Radiation induced immuno-targeting of tumors; targeting in the radiotherapy; biomarkers; targeting; radio-oncological therapy of rectal carcinoma - contribution of radiobiology for therapy optimization; biomarkers for radiation sensibility; resistance mechanisms of tumors; resistance mechanisms of normal tissue; micro ambience, P13L inhibition in radiotherapy: improvement of the local tumor control by molecular mechanisms or the influence of the tumor micro-ambience? DNA repair; radiation effects and technical development.

  19. Radiobiological Effects of Alpha-Particles from Astatine-211: From DNA Damage to Cell Death

    Claesson, Kristina


    In recent years, the use of high linear energy transfer (LET) radiation for radiotherapeutic applications has gained increased interest. Astatine-211 (211At) is an alpha-particle emitting radionuclide, promising for targeted radioimmunotherapy of isolated tumor cells and microscopic clusters. To improve development of safe radiotherapy using 211At it is important to increase our knowledge of the radiobiological effects in cells. During radiotherapy, both tumors and adjacent normal tissue will be irradiated and therefore, it is of importance to understand differences in the radio response between proliferating and resting cells. The aim of this thesis was to investigate effects in fibroblasts with different proliferation status after irradiation with alpha-particles from 211At or X-rays, from inflicted DNA damage, to cellular responses and biological consequences. Throughout this work, irradiation was performed with alpha-particles from 211A or X-rays. The induction and repair of double-strand breaks (DSBs) in human normal fibroblasts were investigated using pulsed-field gel electrophoresis and fragment analysis. The relative biological effectiveness (RBE) of 211At for DSB induction varied between 1.4 and 3.1. A small increase of DSBs was observed in cycling cells compared to stationary cells. The repair kinetics was slower after 211At and more residual damage was found after 24 h. Comparison between cells with different proliferation status showed that the repair was inefficient in cycling cells with more residual damage, regardless of radiation quality. Activation of cell cycle arrests was investigated using immunofluorescent labeling of the checkpoint kinase Chk2 and by measuring cell cycle distributions with flow cytometry analysis. After alpha-particle irradiation, the average number of Chk2-foci was larger and the cells had a more affected cell cycle progression for several weeks compared with X-irradiated cells, indicating a more powerful arrest after 211At

  20. Etude des potentialités des systèmes d'application contrôlée des gouttes (CDA pour les traitements phytosanitaires en céréaliculture (synthèse bibliographique

    Ouled Taleb Salah, S.


    Full Text Available Study of the potential for the use of controlled droplet application (CDA upon cereal crops. A review. Introduction. Controlled droplet application (CDA has the advantage both of the reduction in the span of droplet size distribution and in the volume of liquid applied, in comparison with conventional hydraulic nozzles. Literature. This review investigates the potential for the use of CDA relative to hydraulic nozzles within the early stages of weed control (2-3 leaves. The studies reviewed examine spray retention, linking the droplet characteristics (size, velocity and direction of spray liquids with the architecture, density and wettability of the foliage. These studies show that the use of droplets of 300 µm, combined with an appropriate adjuvant and applied with a 60° forward-angled spray, led to the enhanced depositing of liquids on upright surfaces. Assessment of the reduced volumes applied by both application techniques was based on the mean, the variation coefficient and the deposition coverage. However, these results cannot be generalized, due to the different operative settings in which the spray application techniques were employed. Regarding the risk of drift to the side, the drift potential of droplets generated horizontally by CDA nozzles is greater than that of the conventional technique with a downward orientation of spray. The drift potential increases as the wind velocity increases and the volume median diameter (DV50 decreases. Conclusions. New settings of CDA nozzles in terms of DV50 and the direction of spray may address the challenge of precision agriculture. Innovative ways to apply pesticides, based on CDA, must be explored in order to avoid the sensitivity to wear of the teeth in spray applicators and to obtain a narrower droplet-size distribution.

  1. A radiobiological model of radiotherapy response and its correlation with prognostic imaging variables

    Crispin-Ortuzar, Mireia; Jeong, Jeho; Fontanella, Andrew N.; Deasy, Joseph O.


    Radiobiological models of tumour control probability (TCP) can be personalized using imaging data. We propose an extension to a voxel-level radiobiological TCP model in order to describe patient-specific differences and intra-tumour heterogeneity. In the proposed model, tumour shrinkage is described by means of a novel kinetic Monte Carlo method for inter-voxel cell migration and tumour deformation. The model captures the spatiotemporal evolution of the tumour at the voxel level, and is designed to take imaging data as input. To test the performance of the model, three image-derived variables found to be predictive of outcome in the literature have been identified and calculated using the model’s own parameters. Simulating multiple tumours with different initial conditions makes it possible to perform an in silico study of the correlation of these variables with the dose for 50% tumour control (\\text{TC}{{\\text{D}}50} ) calculated by the model. We find that the three simulated variables correlate with the calculated \\text{TC}{{\\text{D}}50} . In addition, we find that different variables have different levels of sensitivity to the spatial distribution of hypoxia within the tumour, as well as to the dynamics of the migration mechanism. Finally, based on our results, we observe that an adequate combination of the variables may potentially result in higher predictive power.

  2. An Estimation of Radiobiological Parameters for Head-and-Neck Cancer Cells and the Clinical Implications

    Qi, X. Sharon; Yang, Qiuhui; Lee, Steve P.; Li, X. Allen; Wang, Dian


    In vitro survival measurements using two human head-and-neck cancer (HNC) cell lines were performed. The specially designed split-dose surviving fraction was obtained and fitted to the linear-quadratic formalism. The repair halftime (Tr), the potential doubling time (Td), α/β and radiosensitivity α, were estimated. Other radiobiological models: EUD, BED, TCP, etc., were used to examine the potential treatment effectiveness of different IMRT techniques. Our data indicated the repair halftime of ~17 min based on two HNC cell lines. The combined α/β, α and Td are α/β = 8.1 ± 4.1 Gy, α = 0.22 ± 0.08 Gy−1, Td = 4.0 ± 1.8 day, respectively. The prolonged IMRT dose delivery for entire HNC treatment course could possibly result in the loss of biological effectiveness, i.e., the target EUDs decreased by 11% with fraction dose delivery time varying from 5 to 30 min. We determined the sublethal damage repair halftime and other radiobiological parameters for HNC cells, and to evaluate treatment effectiveness of the prolonged dose delivery times associated with different IMRT techniques. The estimated repair halftime for HNC is relatively short and may be comparable to the step-and-shoot IMRT fraction dose delivery time. The effectiveness of IMRT treatment may be improved by reducing the fraction delivery time for HNC treatment. PMID:24213325

  3. A model to describe potential effects of chemotherapy on critical radiobiological treatments

    Rodríguez-Pérez, D.; Desco, M. M.; Antoranz, J. C.


    Although chemo- and radiotherapy can annihilate tumors on their own. they are also used in coadjuvancy: improving local effects of radiotherapy using chemotherapy as a radiosensit.izer. The effects of radiotherapy are well described by current radiobiological models. The goal of this work is to describe a discrete radiotherapy model, that has been previously used describe high radiation dose response as well as unusual radio-responses of some types of tumors (e.g. prostate cancer), to obtain a model of chemo+radiotherapy that can describe how the outcome of their combination is a more efficient removal of the tumor. Our hypothesis is that, although both treatments haven different mechanisms, both affect similar key points of cell metabolism and regulation, that lead to cellular death. Hence, we will consider a discrete model where chemotherapy may affect a fraction of the same targets destroyed by radiotherapy. Although radiotherapy reaches all cells equally, chemotherapy diffuses through a tumor attaining lower concentration in its center and higher in its surface. With our simulations we study the enhanced effect of combined therapy treatment and how it depends on the tissue critical parameters (the parameters of the lion-extensive radiobiological model), the number of “targets” aimed at by chemotherapy, and the concentration and diffusion rate of the drug inside the tumor. The results show that an equivalent, cliemo-radio-dose can be computed that allows the prediction of the lower radiation dose that causes the same effect than a radio-only treatment.

  4. In vivo radiobiological assessment of the new clinical carbon ion beams at CNAO.

    Facoetti, A; Vischioni, B; Ciocca, M; Ferrarini, M; Furusawa, Y; Mairani, A; Matsumoto, Y; Mirandola, A; Molinelli, S; Uzawa, A; Vilches, Freixas G; Orecchia, R


    In this article, the in vivo study performed to evaluate the uniformity of biological doses within an hypothetical target volume and calculate the values of relative biological effectiveness (RBE) at different depths in the spread-out Bragg peak (SOBP) of the new CNAO (National Centre for Oncological Hadrontherapy) carbon beams is presented, in the framework of a typical radiobiological beam calibration procedure. The RBE values (relative to (60)Co γ rays) of the CNAO active scanning carbon ion beams were determined using jejunal crypt regeneration in mice as biological system at the entrance, centre and distal end of a 6-cm SOBP. The RBE values calculated from the iso-effective doses to reduce crypt survival per circumference to 10, ranged from 1.52 at the middle of the SOBP to 1.75 at the distal position and are in agreement with those previously reported from other carbon ion facilities. In conclusion, this first set of in vivo experiments shows that the CNAO carbon beam is radiobiologically comparable with the NIRS (National Institute of Radiological Sciences, Chiba, Japan) and GSI (Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany) ones.

  5. Development of a soft X-ray microprobe for single cell radiobiology

    CHEN Liang; YAN Jingwen; JIANG Shiping; YU Yang


    An X-ray microprobe for radiobiological studies was developed which deliver precise doses of radiation to the selected individual cells. The facility used synchrotron radiation as soft X-ray source. A zone plate combining with a pinhole produced a fine probe from bending magnet for single cell irradiating with defined doses. The diameter of microprobe at the target position was about 2 μm by scanning a knife-edge with an AXUV photo diode. The fluxes of soft X-rays at 516.7 eV (2.4 nm) were about 5.4×104 photons/s.100mA measured with the photo diode. The absorbed dose rate for typical yeast cells was about 11.34 Gy/s with the storage current of 100 mA. A preliminary experiment for yeast cells irradiation has shown that the microprobe had a definite biological effect for radiobiological investigations. The soft X-ray microprobe at "water window" region has provided a useful tool for single cell irradiating damage and a capability of individually irradiating a certain numbers of cells each time.

  6. Bringing the heavy: carbon ion therapy in the radiobiological and clinical context.

    Schlaff, Cody D; Krauze, Andra; Belard, Arnaud; O'Connell, John J; Camphausen, Kevin A


    Radiotherapy for the treatment of cancer is undergoing an evolution, shifting to the use of heavier ion species. For a plethora of malignancies, current radiotherapy using photons or protons yields marginal benefits in local control and survival. One hypothesis is that these malignancies have acquired, or are inherently radioresistant to low LET radiation. In the last decade, carbon ion radiotherapy facilities have slowly been constructed in Europe and Asia, demonstrating favorable results for many of the malignancies that do poorly with conventional radiotherapy. However, from a radiobiological perspective, much of how this modality works in overcoming radioresistance, and extending local control and survival are not yet fully understood. In this review, we will explain from a radiobiological perspective how carbon ion radiotherapy can overcome the classical and recently postulated contributors of radioresistance (α/β ratio, hypoxia, cell proliferation, the tumor microenvironment and metabolism, and cancer stem cells). Furthermore, we will make recommendations on the important factors to consider, such as anatomical location, in the future design and implementation of clinical trials. With the existing data available we believe that the expansion of carbon ion facilities into the United States is warranted.

  7. Radiobiological characterization of post-lumpectomy focal brachytherapy with lipid nanoparticle-carried radionuclides

    Hrycushko, Brian A.; Gutierrez, Alonso N.; Goins, Beth; Yan, Weiqiang; Phillips, William T.; Otto, Pamela M.; Bao, Ande


    Post-operative radiotherapy has commonly been used for early stage breast cancer to treat residual disease. The primary objective of this work was to characterize, through dosimetric and radiobiological modeling, a novel focal brachytherapy technique which uses direct intracavitary infusion of β-emitting radionuclides (186Re/188Re) carried by lipid nanoparticles (liposomes). Absorbed dose calculations were performed for a spherical lumpectomy cavity with a uniformly injected activity distribution using a dose point kernel convolution technique. Radiobiological indices were used to relate predicted therapy outcome and normal tissue complication of this technique with equivalent external beam radiotherapy treatment regimens. Modeled stromal damage was used as a measure of the inhibition of the stimulatory effect on tumor growth driven by the wound healing response. A sample treatment plan delivering 50 Gy at a therapeutic range of 2.0 mm for 186Re-liposomes and 5.0 mm for 188Re-liposomes takes advantage of the dose delivery characteristics of the β-emissions, providing significant EUD (58.2 Gy and 72.5 Gy for 186Re and 188Re, respectively) with a minimal NTCP (0.046%) of the healthy ipsilateral breast. Modeling of kidney BED and ipsilateral breast NTCP showed that large injected activity concentrations of both radionuclides could be safely administered without significant complications.

  8. Radiobiologically optimized couch shift: A new localization paradigm using cone-beam CT for prostate radiotherapy

    Huang, Yimei, E-mail:; Gardner, Stephen J.; Wen, Ning; Zhao, Bo; Gordon, James; Brown, Stephen; Chetty, Indrin J. [Department of Radiation Oncology, Henry Ford Health System, 2799 W Grand Boulevard, Detroit, Michigan 48202 (United States)


    Purpose: To present a novel positioning strategy which optimizes radiation delivery by utilizing radiobiological response knowledge and evaluate its use during prostate external beam radiotherapy. Methods: Five patients with low or intermediate risk prostate cancer were evaluated retrospectively in this IRB-approved study. For each patient, a VMAT plan with one 358° arc was generated on the planning CT (PCT) to deliver 78 Gy in 39 fractions. Five representative pretreatment cone beam CTs (CBCT) were selected for each patient. The CBCT images were registered to PCT by a human observer, which consisted of an initial automated registration with three degrees-of-freedom, followed by manual adjustment for agreement at the prostate/rectal wall interface. To determine the optimal treatment position for each CBCT, a search was performed centering on the observer-matched position (OM-position) utilizing a score function based on radiobiological and dosimetric indices (EUD{sub prostate}, D99{sub prostate}, NTCP{sub rectum}, and NTCP{sub bladder}) for the prostate, rectum, and bladder. We termed the optimal treatment position the radiobiologically optimized couch shift position (ROCS-position). Results: The dosimetric indices, averaged over the five patients’ treatment plans, were (mean ± SD) 79.5 ± 0.3 Gy (EUD{sub prostate}), 78.2 ± 0.4 Gy (D99{sub prostate}), 11.1% ± 2.7% (NTCP{sub rectum}), and 46.9% ± 7.6% (NTCP{sub bladder}). The corresponding values from CBCT at the OM-positions were 79.5 ± 0.6 Gy (EUD{sub prostate}), 77.8 ± 0.7 Gy (D99{sub prostate}), 12.1% ± 5.6% (NTCP{sub rectum}), and 51.6% ± 15.2% (NTCP{sub bladder}), respectively. In comparison, from CBCT at the ROCS-positions, the dosimetric indices were 79.5 ± 0.6 Gy (EUD{sub prostate}), 77.3 ± 0.6 Gy (D99{sub prostate}), 8.0% ± 3.3% (NTCP{sub rectum}), and 46.9% ± 15.7% (NTCP{sub bladder}). Excessive NTCP{sub rectum} was observed on Patient 5 (19.5% ± 6.6%) corresponding to localization at OM

  9. Etude et proposition d’un modèle d’économie d’énergie pour les réseaux de capteurs sans fil : Application médicale sportive.



    Notre mémoire a commencé par une étude générale sur les réseaux de capteurs sans fils, qui a éclairé les différentes facettes des réseaux de capteurs ainsi que leurs caractéristiques essentielles (limitation en énergie, topologie dynamique, mobilité, etc.). Nous avons également parlé de la dimension applicative (médicale, domotique, militaire, etc.) des réseaux de capteurs en raison du lien étroit qui les lie. En effet, avec la grande variété des applications liées aux réseaux ...

  10. Etude d'un continuum de lumière en régime femtoseconde. Applications au domaine biologique : microscopies et spectroscopie en temps résolu.

    Courvoisier, Céline


    For few years, a new type of source, called "continuum of light", has been developed. It presents many advantages like a wideband spectrum, a huge brilliancy, a pulsed nature. The aim of this work is to perform a complete characterization of a continuum generated by the injection of femtosecond pulses into a microstructured fiber, and to consider the use of this continuum as optical source for biomedical applications.With acousto-optic filters, the continuum has been successfully employed as ...

  11. Etude de la contribution des flux activants en soudage A-TIG : application de la silice au soudage de différents métaux et alliages

    RÜckert, Guillaume


    The TIG welding process (Tungsten Inert Gas), extensively used in industry, generates high quality welds by the creation of an electric arc in shielded atmosphere between a non fusible tungsten electrode and the workpiece.The output of this process is, however, low as the weld penetrations above 3mm become increasing problematic with usual welding parameters.This work deals with the application of an activating flux to improve the morphology of welded joints. The A-TIG welding (Activated-TIG)...

  12. Etude de la convection naturelle et de la stratification thermique dans une cavité inclinée et chauffée au milieu : application aux capteurs solaires autostockeurs

    Swiatek, Marie


    Thermal regulation for dwellings in France makes the resort to renewable energy mandatory. Solar energy has an important potential regarding its availability, for both thermal and photovoltaic applications. However, due to its intermittency, there is a need for a storing device. Concerning solar thermal systems, Integrated Collector Storage Solar Water Heaters (ICSSWH) have the advantage of a simple design and use combined with reduced costs compared to more classical devices. These systems a...

  13. Radiological and Environmental Research Division, Center for Human Radiobiology. Annual report, July 1980-June 1981. [Lead abstract


    Separate abstracts were prepared for the 22 papers of this annual report of the Center for Human Radiobiology. Abstracts were not written for 2 appendices which contain data on the exposure and radium-induced malignancies of 2259 persons whose radium content has been determined at least once. (KRM)

  14. Etude et conception de capteurs d'images à pixels actifs et de l'électronique de traitement associée en vue d'applications faible flux

    Solhusvik, Johannes


    Ce travail porte sur l'optimisation d'un système d'imagerie (capteur d'images silicium + chaîne électronique de lecture) en vue d'applications à haute sensibilité, dans le visible et le proche infrarouge. Le faible flux reçu par le capteur se traduit par un bruit statistique Poissonnien important. A ce bruit se rajoutent les bruits propres, blancs et colorés, de la chaîne électronique d'acquisition qui fait suite au capteur. Le rôle de cette chaîne est d'extraire du signal à la sortie du capt...

  15. Systèmes de transmission sans fil multi-émetteurs, multi-récepteurs, pour des applications transports. Etude des modèles de canal de propagation



    Les travaux présentés dans ce mémoire portent sur l'utilisation des techniques Mimo pour des applications dans les transports publics (autobus urbains ou métros). Notre travail de recherche s'est tout particulièrement orienté vers la connaissance et la modélisation du canal de propagation Mimo afin de disposer des outils adaptés lors de l'analyse des performances d'une chaine de transmission mimo. Différents types de modèles de canal Mimo sont présentés dans ce mémoire : les modèles détermini...

  16. Hadron Radiobiology : Investigation of the Inhibition of ten days Growth of Vicia Faba Roots after Exposure in the 600 MeV Neutron Beam from SC2 Hadron Radiobiology : Investigation of the Inhibition of ten days'Grown of Vicia Faba Roots after Exposure in the 600 MeV Neutron Beam from SC2


    Hadron Radiobiology : Investigation of the Inhibition of ten days Growth of Vicia Faba Roots after Exposure in the 600 MeV Neutron Beam from SC2 Hadron Radiobiology : Investigation of the Inhibition of ten days'Grown of Vicia Faba Roots after Exposure in the 600 MeV Neutron Beam from SC2

  17. Modification of radiobiological effects of 171 MeV protons by elements of physical protection

    Bulinina, Taisia; Shurshakov, Vyacheslav; Ivanov, Alexander; Molokanov, Alexander


    Space radiation includes protons of various energies. Physical protection is effective in the case of low energy protons (50-100 MeV) and becomes insufficient for radiation with a high part of high-energy protons. In the experiment performed on outbred mice, the purpose of the study was to evaluate the radiobiological effect of 171 MeV protons and protons modified by elements of physical protection of the spacecraft, on a complex of indicators of the functional condition of the system hematopoiesis and the central nervous system in 24 hours after irradiation at 20 cGy dose. The spacecraft radiation protection elements used in the experiment were a construction of wet hygiene wipes called a «protective curtain», and a glass plate imitating an ISS window. Mass thickness of the " protective curtain" in terms of water equivalent was ̴ 6,2 g/cm2. Physical shielding along the path of 171 MeV protons increases their linear energy transfer leading to the absorbed dose elevation and strengthening of the radiobiological effect. In the experiment, the two types of shielding together raised the absorbed dose from 20 to 23.2 cGy. Chemically different materials (glass and water in the wipes) were found to exert unequal modifying effects on physical and biological parameters of the proton-irradiated mice. There was a distinct dose-dependent reduction of bone marrow cellularity within the dose range from 20 cGy to 23.2 cGy in 24 hours after exposure. No modifying effect of the radiation protection elements on spontaneous motor activity was discovered when compared with entrance protons. The group of animals protected by the glass plate exhibited normal orientative-trying reactions and weakened grip with the forelimbs. The effects observed in the experiment indicate the necessity to carry out comprehensive radiobiological researches (physical, biological and mathematical) in assessing the effects of physical protection, that are actual for ensuring radiation safety of crews in

  18. Proton Radiobiology

    Francesco Tommasino


    Full Text Available In addition to the physical advantages (Bragg peak, the use of charged particles in cancer therapy can be associated with distinct biological effects compared to X-rays. While heavy ions (densely ionizing radiation are known to have an energy- and charge-dependent increased Relative Biological Effectiveness (RBE, protons should not be very different from sparsely ionizing photons. A slightly increased biological effectiveness is taken into account in proton treatment planning by assuming a fixed RBE of 1.1 for the whole radiation field. However, data emerging from recent studies suggest that, for several end points of clinical relevance, the biological response is differentially modulated by protons compared to photons. In parallel, research in the field of medical physics highlighted how variations in RBE that are currently neglected might actually result in deposition of significant doses in healthy organs. This seems to be relevant in particular for normal tissues in the entrance region and for organs at risk close behind the tumor. All these aspects will be considered and discussed in this review, highlighting how a re-discussion of the role of a variable RBE in proton therapy might be well-timed.

  19. Studies of high repetition rate laser-produced plasma soft-X-ray amplifiers; Etudes d'amplificateurs plasma laser a haute cadence dans le domaine X-UV et applications

    Cassou, K


    The progress made as well on the Ti:Sa laser system, as in the control and the knowledge of laser produced X-UV sources allowed the construction of a X-UV laser station dedicated to the applications. My thesis work falls under the development of this station and more particularly on the characterization of a X-UV laser plasma amplifier. The experimental study relates to the coupling improvement of the pump infra-red laser with plasma within the framework of the transient collisional X-UV laser generation. These X-UV lasers are generated in a plasma formed by the interaction of a solid target and a laser pulse of approximately 500 ps duration, followed by a second infra-red laser pulse known as of pump (about 5 ps) impinging on the target in grazing incidence. For the first time, a complete parametric study was undertaken on the influence of the grazing angle on the pumping of the amplifying medium. One of the results was to reach very high peak brightness about 10{sup 28} ph/s/mm{sup 2}/mrad{sup 2}/(0.1%bandwidth), which compares well with the free-electron laser brightness. Moreover, we modified then used a new two-dimensional hydrodynamic code with adaptive mesh refinement in order to understand the influence of the space-time properties of the infra-red laser on the formation and the evolution of the amplifying plasma. Our modeling highlighted the interest to use a super Gaussian transverse profile for the line focus leading to an increase in a factor two of the gain region size and a reduction of the electron density gradient by three orders of magnitude. These improvements should strongly increase the energy contained in X-UV laser beam. We thus used X-UV laser to study the appearance of transient defects produced by a laser IR on a beam-splitter rear side. We also began research on the mechanisms of DNA damage induced by a very intense X-UV radiation. (author)

  20. AFRRI (Armed Forces Radiobiology Research Institute) reports, July, August and September 1986. Technical report


    Contents include: post-radiation regional cerebral blood flow in primates; heart-function studies in dogs after acute gamma irradiation of the precordium; the effect of anesthetic, sedative or narcotic drugs on intrahepatic and extrahepatic biliary kinetics; effect of gamma radiation on sodium channels in different conformations in neuroblastoma cells; effects of ethanol exposure on brain sodium channels; ionizing radiation alters the properties of sodium channels in rat brain synaptosomes; thymic hormones in thymus recovery from radiation injury; acute toxicity of petroleum- and shale-derived distillate fuel; light microscopic, hematologic, and serum chemistry studies; radioprotective properties of detoxified lipid A from Salmonella Minnesota R595; brain areas involved in production of morphine-induced locomotor hyperactivity of the C57B1/6J mouse; preliminary evaluation of US Army radiac detector DT-236/PD and radiac computer-indicator CP-696/UD; and calorimetric dose measurements and calorimetric system developed for the armed forces radiobiology research institute.

  1. Heavy charged particle radiobiology: using enhanced biological effectiveness and improved beam focusing to advance cancer therapy.

    Allen, Christopher; Borak, Thomas B; Tsujii, Hirohiko; Nickoloff, Jac A


    Ionizing radiation causes many types of DNA damage, including base damage and single- and double-strand breaks. Photons, including X-rays and γ-rays, are the most widely used type of ionizing radiation in radiobiology experiments, and in radiation cancer therapy. Charged particles, including protons and carbon ions, are seeing increased use as an alternative therapeutic modality. Although the facilities needed to produce high energy charged particle beams are more costly than photon facilities, particle therapy has shown improved cancer survival rates, reflecting more highly focused dose distributions and more severe DNA damage to tumor cells. Despite early successes of charged particle radiotherapy, there is room for further improvement, and much remains to be learned about normal and cancer cell responses to charged particle radiation.

  2. Radiobiological studies with the nematode Caenorhabditis elegans. Genetic and developmental effects of high LET radiation

    Nelson, G.A.; Schubert, W.W.; Marshall, T.M. (Jet Propulsion Lab., Pasadena, CA (United States))


    The biological effects of heavy charged particle (HZE) radiation are of particular interest to travellers and planners for long-duration space flights where exposure levels represents a potential health hazard. The unique feature of HZE radiation is the structured pattern of its energy deposition in targets. There are many consequences of this feature to biological endpoints when compared with effects of ionizing photons. Dose vs response and dose-rate kinetics may be modified, DNA and cellular repair systems may be altered in their abilities to cope with damage, and the qualitative features of damage may be unique for different ions. The nematode Caenorhabditis elegans is being used to address these and related questions associated with exposure to radiation. HZE-induced mutation, chromosome aberration, cell inactivation and altered organogenesis are discussed along with plans for radiobiological experiments in space. (author).

  3. Radiobiological studies with the nematode Caenorhabditis elegans. Genetic and developmental effects of high LET radiation

    Nelson, G. A.; Schubert, W. W.; Marshall, T. M.


    The biological effects of heavy charged particle (HZE) radiation are of particular interest to travellers and planners for long-duration space flights where exposure levels represent a potential health hazard. The unique feature of HZE radiation is the structured pattern of its energy deposition in targets. There are many consequences of this feature to biological endpoints when compared with effects of ionizing photons. Dose vs response and dose-rate kinetics may be modified, DNA and cellular repair systems may be altered in their abilities to cope with damage, and the qualitative features of damage may be unique for different ions. The nematode Caenorhabditis elegans is being used to address these and related questions associated with exposure to radiation. HZE-induced mutation, chromosome aberration, cell inactivation and altered organogenesis are discussed along with plans for radiobiological experiments in space.

  4. Chasing Ghosts in Space Radiobiology Research: The Lost Focus on Non-Targeted Effects

    Cucinotta, Francis; Saganti, Premkumar; Cacao, Eliedonna


    The doses and dose-rates of astronaut exposures to galactic cosmic rays (GCR) are accurately known, and lead to particle hits per cell nucleus from high charge and energy (HZE) particles of much less than one hit per cell per week. A large number of experiments have shown that additivity of biological effects is a valid assumption for space radiation exposures, while experiments at higher doses and dose-rates than occur in space continue to be a focus of the majority of space radiobiology research. Furthermore HZE particle exposures with mono-energetic particles manifest themselves as a mixed-radiation field due to the contributions of delta-rays and the random impact parameter of a particles track core to DNA and non-DNA targets in cells and tissues. The mixed-field manifestation of mono-energetic HZE particle exposures is well known from theoretical studies of microdosimetry and track structure. Additional mixed-field effects occur for single species experiments due to nuclear fragmentation in particle accelerator beam-lines and biological samples along with energy straggling. In contrast to these well known aspects of space radiobiology there are many open questions on the contribution of non-targeted effects to low dose and dose-rate exposures. Non-targeted effects (NTEs) include bystander effects and genomic instability, and have been shown to be the most important outstanding question for reducing uncertainties in space radiation cancer risk assessment. The dose-rate and radiation quality dependence of NTE's has not been established, while there is an over-arching need to develop 21st century experimental models of human cancer risk. We review possible mechanisms of NTE's and how new experiments to address these issues could be designed.

  5. Transnational science and collaborative networks. The case of Genetics and Radiobiology in Mexico, 1950-1970.

    Barahona, Ana


    The transnational approach of the science and technology studies (S&TS) abandons the nation as a unit of analysis in order to understand the development of science history. It also abandons Euro-US-centred narratives in order to explain the role of international collaborative networks and the circulation of knowledge, people, artefacts and scientific practices. It is precisely under this perspective that the development of genetics and radiobiology in Mexico shall be analyzed, together with the pioneering work of the Mexican physician-turned-geneticist Alfonso León de Garay who spent two years in the Galton Laboratory in London under the supervision of Lionel Penrose. Upon his return de Garay funded the Genetics and Radiobiology Program of the National Commission of Nuclear Energy based on local needs and the aim of working beyond geographical limitations to thus facilitate the circulation of knowledge, practices and people. The three main lines of research conducted in the years after its foundation that were in line with international projects while responding to the national context were, first, cytogenetic studies of certain abnormalities, and the cytogenetics and anthropological studies of the Olympic Games held in Mexico in 1968; second, the study of the effects of radiation on hereditary material; and third, the study of population genetics in Drosophila and in Mexican indigenous groups. The program played a key role in reshaping the scientific careers of Mexican geneticists, and in transferring locally sourced research into broader networks. This case shows the importance of international collaborative networks and circulation in the constitution of national scientific elites, and also shows the national and transnational concerns that shaped local practices.

  6. Optimization in brachytherapy with the implementation of Radiobiology; Optimizacion en Braquiterapia con la implementacion de la Radiobiologia

    Duran, M.P.; Bourel, V.J.; Rodriguez, I.; Torre, M. de la; Caneva, S. [Braqui S.R.L. Viamonte 1861, Buenos Aires (Argentina)


    In the brachytherapy planning treatments with High dose rates (HDR), the optimization algorithms used are based in dosimetric considerations and/or geometric ones, ignoring the radiobiological response of the tissue treated. In this work we wish to show the implementation of radiobiological concepts in the optimization. Assuming that the subtiles differences that result in the dose distribution among the different optimization models which are not visible in an isodose plane, it is studied how is classically make it , the quality implant through natural histograms about dose volumes and the resulting parameters. Also is studied the necrosis probability which may be caused by the choice of some optimization model, allowing with this the choice of the best implant. (Author)

  7. Comp Plan: A computer program to generate dose and radiobiological metrics from dose-volume histogram files.

    Holloway, Lois Charlotte; Miller, Julie-Anne; Kumar, Shivani; Whelan, Brendan M; Vinod, Shalini K


    Treatment planning studies often require the calculation of a large number of dose and radiobiological metrics. To streamline these calculations, a computer program called Comp Plan was developed using MATLAB. Comp Plan calculates common metrics, including equivalent uniform dose, tumor control probability, and normal tissue complication probability from dose-volume histogram data. The dose and radiobiological metrics can be calculated for the original data or for an adjusted fraction size using the linear quadratic model. A homogeneous boost dose can be added to a given structure if desired. The final output is written to an Excel file in a format convenient for further statistical analysis. Comp Plan was verified by independent calculations. A lung treatment planning study comparing 45 plans for 7 structures using up to 6 metrics for each structure was successfully analyzed within approximately 5 minutes with Comp Plan. The code is freely available from the authors on request.

  8. An Expanded Multi-scale Monte Carlo Simulation Method for Personalized Radiobiological Effect Estimation in Radiotherapy: a feasibility study

    Zhang, Ying; Feng, Yuanming; Wang, Wei; Yang, Chengwen; Wang, Ping


    A novel and versatile “bottom-up” approach is developed to estimate the radiobiological effect of clinic radiotherapy. The model consists of multi-scale Monte Carlo simulations from organ to cell levels. At cellular level, accumulated damages are computed using a spectrum-based accumulation algorithm and predefined cellular damage database. The damage repair mechanism is modeled by an expanded reaction-rate two-lesion kinetic model, which were calibrated through replicating a radiobiological experiment. Multi-scale modeling is then performed on a lung cancer patient under conventional fractionated irradiation. The cell killing effects of two representative voxels (isocenter and peripheral voxel of the tumor) are computed and compared. At microscopic level, the nucleus dose and damage yields vary among all nucleuses within the voxels. Slightly larger percentage of cDSB yield is observed for the peripheral voxel (55.0%) compared to the isocenter one (52.5%). For isocenter voxel, survival fraction increase monotonically at reduced oxygen environment. Under an extreme anoxic condition (0.001%), survival fraction is calculated to be 80% and the hypoxia reduction factor reaches a maximum value of 2.24. In conclusion, with biological-related variations, the proposed multi-scale approach is more versatile than the existing approaches for evaluating personalized radiobiological effects in radiotherapy. PMID:28322329

  9. An Expanded Multi-scale Monte Carlo Simulation Method for Personalized Radiobiological Effect Estimation in Radiotherapy: a feasibility study

    Zhang, Ying; Feng, Yuanming; Wang, Wei; Yang, Chengwen; Wang, Ping


    A novel and versatile “bottom-up” approach is developed to estimate the radiobiological effect of clinic radiotherapy. The model consists of multi-scale Monte Carlo simulations from organ to cell levels. At cellular level, accumulated damages are computed using a spectrum-based accumulation algorithm and predefined cellular damage database. The damage repair mechanism is modeled by an expanded reaction-rate two-lesion kinetic model, which were calibrated through replicating a radiobiological experiment. Multi-scale modeling is then performed on a lung cancer patient under conventional fractionated irradiation. The cell killing effects of two representative voxels (isocenter and peripheral voxel of the tumor) are computed and compared. At microscopic level, the nucleus dose and damage yields vary among all nucleuses within the voxels. Slightly larger percentage of cDSB yield is observed for the peripheral voxel (55.0%) compared to the isocenter one (52.5%). For isocenter voxel, survival fraction increase monotonically at reduced oxygen environment. Under an extreme anoxic condition (0.001%), survival fraction is calculated to be 80% and the hypoxia reduction factor reaches a maximum value of 2.24. In conclusion, with biological-related variations, the proposed multi-scale approach is more versatile than the existing approaches for evaluating personalized radiobiological effects in radiotherapy.

  10. Radiobiological evaluation of prostate cancer IMRT and conformal-RT plans using different treatment protocols.

    Mavroidis, Panayiotis; Komisopoulos, Georgios; Buckey, Courtney; Mavroeidi, Margarita; Swanson, Gregory P; Baltas, Dimos; Papanikolaou, Nikos; Stathakis, Sotirios


    The purpose of this study is to evaluate the clinical efficacy of both step-and-shoot IMRT and 3D-Conformal Radiation Therapy modalities (CRT) in treating prostate cancer using radiobiological measures. Another aim was to estimate the risks for developing secondary malignancies in bladder and rectum due to radiotherapy from the corresponding modalities. The treatment plans of ten prostate cancer patients were developed using IMRT and CRT. For the IMRT plans, two beam energies and two treatment protocols were used (the RTOG 0415 and a most restrictive one proposed by Fox Chase Cancer Center (FCCC)). For the evaluation of these plans, the complication-free tumor control probability, the total probability of injury, the total probability of control/benefit, and the biologically effective uniform dose were employed. Furthermore, based on the dosimetric data of IMRT and CRT, the risk for secondary malignancies was calculated for bladder and rectum. The average risk for secondary malignancy was lower for the bladder (0.37%) compared to the rectum (0.81%) based on all the treatment plans of the ten prostate cancer patients. The highest average risk for secondary malignancy for bladder and rectum was for the CRT-6X modality (0.46% and 1.12%, respectively) and the lowest was for the IMRT RTOG-18X modality (0.33% and 0.56%, respectively). The ≥ Grade 2 LENT/SOMA response probability was lower for the bladder than for the rectum in all the plans. For the bladder the highest average value was for the IMRT RTOG-18X (0.9%) and the lowest was for the CRT-18X modality (0.1%). For the rectum, the highest average value was for the IMRT RTOG-6X (11.9%) and the lowest was for the IMRT FCCC-18X modality (2.2%). By using radiobiological measures it is shown that the IMRT FCCC plans had the lowest risks for normal tissue complications, whereas the IMRT RTOG had the highest. Regarding the risk for secondary malignancies, the CRT plans showed the highest values for both bladder and

  11. Radioembolisation with {sup 90}Y-microspheres: dosimetric and radiobiological investigation for multi-cycle treatment

    Cremonesi, Marta; Ferrari, Mahila; Pedroli, Guido [European Institute of Oncology, Unit of Medical Physics, Milan (Italy); Bartolomei, Mirco; Arico, Demetrio; De Cicco, Concetta [European Institute of Oncology, Division of Nuclear Medicine, Milan (Italy); Orsi, Franco; Bonomo, Guido [European Institute of Oncology, Unit of Interventistic Radiology, Milan (Italy); Mallia, Andrew [Gamma Unit, Radiology Department, St. Luke' s Hospital (Malta); Paganelli, Giovanni [European Institute of Oncology, Division of Nuclear Medicine, Milan (Italy)


    Radioembolisation with {sup 90}Y-microspheres is a new locoregional treatment of hepatic lesions, usually applied as single cycle. Multi-cycle treatments might be considered as a strategy to improve the risk-benefit balance. With the aim to derive suitable information for patient tailored therapy, available patients' dosimetric data were reviewed according to the linear-quadratic model and converted into biological effective dose (BED) values. Single vs. multi-cycle approaches were compared through radiobiological perspective. Twenty patients with metastatic lesions underwent radioembolisation. The {sup 90}Y-administered activity (AA) was established in order to respect a precautionary limit dose (40 Gy) for the non-tumoral liver (NTL). BED was calculated setting {alpha}/{beta} = 2.5 Gy (NTL), 10 Gy (tumours); T{sub 1/2,eff} = T{sub 1/2,phys} = 64.2 h; T{sub 1/2,rep} = 2.5 h (NTL), 1.5 h (tumours). The BED to NTL was considered as a constraint for multi-cycle approach. The AA for two cycles and the percent variations of AA, tumour dose, BED were estimated. In one-cycle, for a prescribed BED to NTL of 64 Gy (NTL dose = 40 Gy), AA was 1.7 (0.9-3.2) GBq, tumour dose was 130 (65-235) Gy, and tumour BED was 170 (75-360) Gy. Considering two cycles, {proportional_to}15% increase was found for AA and dose to NTL, with unvaried BED for NTL. Tumour dose increase was 20 (10-35) Gy; tumour BED increase was 10 (3-11) Gy. In different protocols allowing 80 Gy to NTL, the BED sparing estimated was {proportional_to}50 Gy (two cycles) and 65 Gy (three cycles). From a radiobiological perspective, multi-cycle treatments would allow administering higher activities with increased tumour irradiation and preserved radiation effects on NTL. Trials comparing single vs. multiple cycles are suggested. (orig.)

  12. Cell survivor: Modeling radiobiological phenomena with a new kind of simulation

    Spencer, Melissa A.

    Despite widespread societal fear of radiation, whether justified or unjustified, and whether related to medicine (e.g., CT scans) or other forms of nuclear and atomic radiation (e.g., nuclear power) there is a fundamental lack of basic understanding of radiation effects on the human body. Different types of radiation are psychologically grouped into the same general fear category irrespective of their different potential to do harm, and this fear is not balanced by their potential beneficial effects. By modeling certain types of radiation biology experiments within a game engine, it is possible to enhance the player's intuitive understanding of radiobiology, both the effects of different types of radiation as well as different environmental factors that can enhance or suppress repair. For this dissertation, a game/simulation has been developed that intends to narrow the gap between public perception and the reality of these physical processes. The building blocks of this simulation are cells, which are damaged by incident radiation, accumulating either single or double strand breaks. They grow and reproduce, and are especially vulnerable during certain phases of the cell cycle (e.g. mitosis). Two dominant damage mechanisms are modeled, along with multiple repair mechanisms, for example, double strand breaks can be repaired by either non-homologous end joining or homologous repair. The output of the developed simulation was compared to data collected in experimental studies and the simulation appears to be a valid representation of the dominant mechanisms of radiobiology, as far as can be determined within the scope of this dissertation. Cell survival curves generated from playtest data display shoulders that depend on the LET of incident radiation, and rest time restores repair capability. In addition to public outreach, the presented code can be used to aid investigators by collecting data during play that can be used as a distributed Monte Carlo simulation

  13. Ionization of biomolecular targets by ion impact: input data for radiobiological applications

    de Vera, Pablo; Abril, Isabel; Garcia-Molina, Rafael; Solov'yov, Andrey V.


    In this work we review and further develop a semiempirical model recently proposed for the ion impact ionization of complex biological media. The model is based on the dielectric formalism, and makes use of a semiempirical parametrization of the optical energy-loss function of bioorganic compounds, allowing the calculation of single and total ionization cross sections and related quantities for condensed biological targets, such as liquid water, DNA and its components, proteins, lipids, carbohydrates or cell constituents. The model shows a very good agreement with experimental data for water, adenine and uracil, and allows the comparison of the ionization efficiency of different biological targets, and also the average kinetic energy of the ejected secondary electrons.

  14. A radiobiological model of metastatic burden reduction for molecular radiotherapy: application to patients with bone metastases

    Denis-Bacelar, Ana M.; Chittenden, Sarah J.; Murray, Iain; Divoli, Antigoni; McCready, V. Ralph; Dearnaley, David P.; O’Sullivan, Joe M.; Johnson, Bernadette; Flux, Glenn D.


    Skeletal tumour burden is a biomarker of prognosis and survival in cancer patients. This study proposes a novel method based on the linear quadratic model to predict the reduction in metastatic tumour burden as a function of the absorbed doses delivered from molecular radiotherapy treatments. The range of absorbed doses necessary to eradicate all the bone lesions and to reduce the metastatic burden was investigated in a cohort of 22 patients with bone metastases from castration-resistant prostate cancer. A metastatic burden reduction curve was generated for each patient, which predicts the reduction in metastatic burden as a function of the patient mean absorbed dose, defined as the mean of all the lesion absorbed doses in any given patient. In the patient cohort studied, the median of the patient mean absorbed dose predicted to reduce the metastatic burden by 50% was 89 Gy (interquartile range: 83–105 Gy), whilst a median of 183 Gy (interquartile range: 107–247 Gy) was found necessary to eradicate all metastases in a given patient. The absorbed dose required to eradicate all the lesions was strongly correlated with the variability of the absorbed doses delivered to multiple lesions in a given patient (r  =  0.98, P  <  0.0001). The metastatic burden reduction curves showed a potential large reduction in metastatic burden for a small increase in absorbed dose in 91% of patients. The results indicate the range of absorbed doses required to potentially obtain a significant survival benefit. The metastatic burden reduction method provides a simple tool that could be used in routine clinical practice for patient selection and to indicate the required administered activity to achieve a predicted patient mean absorbed dose and reduction in metastatic tumour burden.

  15. TU-CD-303-00: In Memoriam of Warren Sinclair: Physics Applications for New Radiobiology



    The Medical Physics and Radiation Protection communities lost one of their true pioneers in May, 2014 with the passing of Warren K. Sinclair, Ph.D. He received his Doctorate in Physics at the University of London, U.K. He was a fellow of the Institute of Physics and a Certified Health Physicist. After a number of posts at Hospitals and Universities in the U.K. and New Zealand, he became the Head, Physics Department at the M.D. Anderson Hospital, Houston, TX. He held a number of academic physics positions with the University of Texas, Austin at the main campus and at the Postgraduate School of Medicine, Houston. He later served as a Senior Biophysicist, Division Director, and then Associate Laboratory Director for Biomedical Division Director, and then Associate Laboratory Director for Biomedical and Environmental Research at the Argonne National Laboratory, IL. He had additional academic appointments at the University of California, Berkeley; Northern Illinois University; the University of Illinois (Chicago Circle Campus); and the University of Chicago. Warren was a charter member of the AAPM and a leader in many communities: President of the AAPM from 1960 to 1961 and the Journal Editor from 1964 to 1969, the 2nd President of the NCRP from 1977 to 1991, and the President of the Radiation Research Society from 1978 to 1979. His many awards included the William D. Coolidge Award in 1986. Even this barely scratches the surface of the many other organizations he served with and influenced including the ICRP, IOP, RSNA, SNM, and UNSCEAR. His research interests resulted in publications from 1948 to the 1990s in many aspects (physical and biological) of radiotherapy and the effects of ionizing radiation in general, leading to early definitions of RBE values for megavoltage radiotherapy as well as contributing to the development of the modern framework for radiation protection worldwide. Warren was not a retiring person and even after moving to NCRP President Emeritus status continued to provide advice and comments on publications and to mentor others until the time of his passing. Sadly, Warren’s long-time wife Joy passed away in December, 2014 but he is survived by his son Bruce and daughter Roslyn, 2 grandchildren and 4 great-grandchildren.

  16. Radiobiological evaluation of the influence of dwell time modulation restriction in HIPO optimized HDR prostate brachytherapy implants

    Dimos Baltas


    Full Text Available Purpose: One of the issues that a planner is often facing in HDR brachytherapy is the selective existence of high dose volumes around some few dominating dwell positions. If there is no information available about its necessity (e.g. location of a GTV, then it is reasonable to investigate whether this can be avoided. This effect can be eliminated by limiting the free modulation of the dwell times. HIPO, an inverse treatment plan optimization algorithm, offers this option.In treatment plan optimization there are various methods that try to regularize the variation of dose non-uniformity using purely dosimetric measures. However, although these methods can help in finding a good dose distribution they do not provide any information regarding the expected treatment outcome as described by radiobiology based indices.Material and methods: The quality of 12 clinical HDR brachytherapy implants for prostate utilizing HIPO and modulation restriction (MR has been compared to alternative plans with HIPO and free modulation (without MR.All common dose-volume indices for the prostate and the organs at risk have been considered together with radiobiological measures. The clinical effectiveness of the different dose distributions was investigated by calculating the response probabilities of the tumors and organs-at-risk (OARs involved in these prostate cancer cases. The radiobiological models used are the Poisson and the relative seriality models. Furthermore, the complication-free tumor control probability, P+ and the biologically effective uniform dose (D = were used for treatment plan evaluation and comparison.Results: Our results demonstrate that HIPO with a modulation restriction value of 0.1-0.2 delivers high quality plans which are practically equivalent to those achieved with free modulation regarding the clinically used dosimetric indices.In the comparison, many of the dosimetric and radiobiological indices showed significantly different results. The

  17. Radiobiological mechanisms of stereotactic body radiation therapy and stereotactic radiation surgery

    Kim, Mi Sook; Kim, Won Woo; Park, In Hwan; Kim, Hee Jong; Lee, Eun Jin; Jung, Jae Hoon [Research Center for Radiotherapy, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Cho, Lawrence Chin Soo; Song, Chang W. [Dept. of Radiation Oncology, University of Minnesota Medical School, Minneapolis (United States)


    Despite the increasing use of stereotactic body radiation therapy (SBRT) and stereotactic radiation surgery (SRS) in recent years, the biological base of these high-dose hypo-fractionated radiotherapy modalities has been elusive. Given that most human tumors contain radioresistant hypoxic tumor cells, the radiobiological principles for the conventional multiple-fractionated radiotherapy cannot account for the high efficacy of SBRT and SRS. Recent emerging evidence strongly indicates that SBRT and SRS not only directly kill tumor cells, but also destroy the tumor vascular beds, thereby deteriorating intratumor microenvironment leading to indirect tumor cell death. Furthermore, indications are that the massive release of tumor antigens from the tumor cells directly and indirectly killed by SBRT and SRS stimulate anti-tumor immunity, thereby suppressing recurrence and metastatic tumor growth. The reoxygenation, repair, repopulation, and redistribution, which are important components in the response of tumors to conventional fractionated radiotherapy, play relatively little role in SBRT and SRS. The linear-quadratic model, which accounts for only direct cell death has been suggested to overestimate the cell death by high dose per fraction irradiation. However, the model may in some clinical cases incidentally do not overestimate total cell death because high-dose irradiation causes additional cell death through indirect mechanisms. For the improvement of the efficacy of SBRT and SRS, further investigation is warranted to gain detailed insights into the mechanisms underlying the SBRT and SRS.

  18. Radiograaff, a proton irradiation facility for radiobiological studies at a 4 MV Van de Graaff accelerator

    Constanzo, J. [Université de Lyon, F-69622, Lyon (France); Université Lyon 1, Villeurbanne (France); CNRS/IN2P3, Institut de Physique Nucléaire de Lyon, F-69622 Villeurbanne (France); Fallavier, M., E-mail: [Université de Lyon, F-69622, Lyon (France); Université Lyon 1, Villeurbanne (France); CNRS/IN2P3, Institut de Physique Nucléaire de Lyon, F-69622 Villeurbanne (France); Alphonse, G. [Université de Lyon, F-69622, Lyon (France); Université Lyon 1, Villeurbanne (France); Faculté de Médecine Lyon-Sud, LRCM, F-69921 Oullins (France); Hospices-Civils-de-Lyon, CHLS, F-69495 Pierre-Bénite (France); Bernard, C. [Université de Lyon, F-69622, Lyon (France); Université Lyon 1, Villeurbanne (France); CNRS/IN2P3, Institut de Physique Nucléaire de Lyon, F-69622 Villeurbanne (France); Battiston-Montagne, P. [Université de Lyon, F-69622, Lyon (France); Université Lyon 1, Villeurbanne (France); Faculté de Médecine Lyon-Sud, LRCM, F-69921 Oullins (France); Rodriguez-Lafrasse, C. [Université de Lyon, F-69622, Lyon (France); Université Lyon 1, Villeurbanne (France); Faculté de Médecine Lyon-Sud, LRCM, F-69921 Oullins (France); Hospices-Civils-de-Lyon, CHLS, F-69495 Pierre-Bénite (France); and others


    A horizontal beam facility for radiobiological experiments with low-energy protons has been set up at the 4 MV Van de Graaff accelerator of the Institut de Physique Nucléaire de Lyon. A homogeneous irradiation field with a suitable proton flux is obtained by means of two collimators and two Au-scattering foils. A monitoring chamber contains a movable Faraday cup, a movable quartz beam viewer for controlling the intensity and the position of the initial incident beam and four scintillating fibers for beam monitoring during the irradiation of the cell samples. The beam line is ended by a thin aluminized Mylar window (12 μm thick) for the beam extraction in air. The set-up was simulated by the GATE v6.1 Monte-Carlo platform. The measurement of the proton energy distribution, the evaluation of the fluence-homogeneity over the sample and the calibration of the monitoring system were performed using a silicon PIPS detector, placed in air in the same position as the biological samples to be irradiated. The irradiation proton fluence was found to be homogeneous to within ±2% over a circular field of 20 mm diameter. As preliminary biological experiment, two Human Head and Neck Squamous Carcinoma Cell lines (with different radiosensitivities) were irradiated with 2.9 MeV protons. The measured survival curves are compared to those obtained after X-ray irradiation, giving a Relative Biological Efficiency between 1.3 and 1.4.

  19. Radiobiology of Small Hive Beetle (Coleoptera: Nitidulidae) and Prospects for Management Using Sterile Insect Releases.

    Downey, Danielle; Chun, Stacey; Follett, Peter


    Small hive beetle, Aethina tumida Murray (Coleoptera: Nitidulidae), is considered a serious threat to beekeeping in the Western Hemisphere, Australia, and Europe mainly due to larval feeding on honey, pollen, and brood of the European honeybee, Apis mellifera L. Control methods are limited for this pest. Studies were conducted to provide information on the radiobiology of small hive beetle and determine the potential for sterile insect releases as a control strategy. Adult males and females were equally sensitive to a radiation dose of 80 Gy and died within 5-7 d after treatment. In reciprocal crossing studies, irradiation of females only lowered reproduction to a greater extent than irradiation of males only. For matings between unirradiated males and irradiated females, mean reproduction was reduced by >99% at 45 and 60 Gy compared with controls, and no larvae were produced at 75 Gy. Irradiation of prereproductive adults of both sexes at 45 Gy under low oxygen (1-4%) caused a high level of sterility (>99%) while maintaining moderate survivorship for several weeks, and should suffice for sterile insect releases. Sterile insect technique holds potential for suppressing small hive beetle populations in newly invaded areas and limiting its spread.

  20. Late radiation-induced heart disease after radiotherapy. Clinical importance, radiobiological mechanisms and strategies of prevention.

    Andratschke, Nicolaus; Maurer, Jean; Molls, Michael; Trott, Klaus-Rüdiger


    The clinical importance of radiation-induced heart disease, in particular in post-operative radiotherapy of breast cancer patients, has been recognised only recently. There is general agreement, that a co-ordinated research effort would be needed to explore all the potential strategies of how to reduce the late risk of radiation-induced heart disease in radiotherapy. This approach would be based, on one hand, on a comprehensive understanding of the radiobiological mechanisms of radiation-induced heart disease after radiotherapy which would require large-scale long-term animal experiments with high precision local heart irradiation. On the other hand - in close co-operation with mechanistic in vivo research studies - clinical studies in patients need to determine the influence of dose distribution in the heart on the risk of radiation-induced heart disease. The aim of these clinical studies would be to identify the critical structures within the organ which need to be spared and their radiation sensitivity as well as a potential volume and dose effect. The results of the mechanistic studies might also provide concepts of how to modify the gradual progression of radiation damage in the heart by drugs or biological molecules. The results of the studies in patients would need to also incorporate detailed dosimetric and imaging studies in order to develop early indicators of impending radiation-induced heart disease which would be a pre-condition to develop sound criteria for treatment plan optimisation. Copyright © 2010. Published by Elsevier Ireland Ltd.

  1. Radiobiological inactivation of Epstein-Barr virus. [UV and X radiation

    Henderson, E.; Heston, L.; Grogan, E.; Miller, G.


    Lymphocyte transforming properties of B95-8 strain Epstein-Barr virus (EBV) are very sensitive to inactivation by either uv or x irradiation. No dose of irradiation increases the transforming capacity of EBV. The x-ray dose needed for inactivation of EBV transformation (dose that results in 37% survival, 60,000 rads) is similar to the dose required for inactivation of plaque formation by herpes simplex virus type 1 (Fischer strain). Although herpes simplex virus is more sensitive than EBV to uv irradiation, this difference is most likely due to differences in the kinetics or mechanisms of repair of uv damage to the two viruses. The results lead to the hypothesis that a large part, or perhaps all, of the EBV genome is in some way needed to initiate transformation. The abilities of EBV to stimulate host cell DNA synthesis, to induce nuclear antigen, and to immortalize are inactivated in parallel. All clones of marmoset cells transformed by irradiated virus produce extracellular transforming virus. These findings suggest that the abilities of the virus to transform and to replicate complete progeny are inactivated together. The amounts of uv and x irradiation that inactivate transformation by B95-8 virus are less than the dose needed to inactivate early antigen induction by the nontransforming P/sub 3/HR-1 strain of EBV. Based on radiobiological inactivation, 10 to 50% of the genome is needed for early antigen induction.

  2. Radiobiology and Reproduction—What Can We Learn from Mammalian Females?

    Montserrat Garcia-Caldés


    Full Text Available Ionizing radiation damages DNA and induces mutations as well as chromosomal reorganizations. Although radiotherapy increases survival among cancer patients, this treatment does not come without secondary effects, among which the most problematic is gonadal dysfunction, especially in women. Even more, if radio-induced DNA damage occurs in germ cells during spermatogenesis and/or oogenesis, they can produce chromosomal reorganizations associated with meiosis malfunction, abortions, as well as hereditary effects. However, most of our current knowledge of ionizing radiation genotoxic effects is derived from in vitro studies performed in somatic cells and there are only some experimental data that shed light on how germ cells work when affected by DNA alterations produced by ionizing radiation. In addition, these few data are often related to mammalian males, making it difficult to extrapolate the results to females. Here, we review the current knowledge of radiobiology and reproduction, paying attention to mammalian females. In order to do that, we will navigate across the female meiotic/reproductive cycle/life taking into account the radiation-induced genotoxic effects analysis and animal models used, published in recent decades.

  3. AFRRI (Armed Forces Radiobiology Research Institute) reports, April, May, June 1987. Technical report


    This document is a collection of reprinted technical reports. Partial contents include: Effect of ionizing radiation on prostaglandins and gastric secretion in rhesus monkeys; Characterization of rat prothymocyte with monoclonal antibodies recognizing rat lymphocyte membrane antigenic determinants; Effects of subdiaphragmatic vagotomy on the acquisition of a radiation-induced condition taste aversion; Ethanol-induced taste aversions; Lack of involvement of acetaldehyde and the area postrema; Dose and time relationships of the radioprotector WR-2721 on locomotor activity in mice; Purification and analysis of rat hematopoietic stem cells by flow cytometry, Plasma histamine and catecholamine levels during hypotension induced by morphine and compound 48/80; Effects of ionizing radiation on hippocampal excitability, Tumor necrosis factor/cachectin is a less-potent inducer of serum amyloid A synthesis than interleukin 1, Protection of mice against fission-neutron irradiation by WR-2721 or WR-151327, Induction of colony-stimulating factor in vivo by recombinant interleukin 1 a and recombinant tumor necrosis factor alpha; 16,16-Dimethyl prostaglandin E2 increases survival in mice following irradiation, Selenium pretreatment enhances the radioprotective effect and reduces the lethal toxicity of WR-2721; Rat phantom depth dose studies in electron, x-ray, gamma-ray, and reactor-radiation fields; Wall attenuation and scatter characteristics of ionization chambers at Armed Forces Radiobiology Research Institute.

  4. AFRRI (Armed Forces Radiobiology Research Institute) reports, July, August, September 1989. Technical report


    This volume contains AFRRI Scientific Reports SR 89-26 through SR89-39 and Technical Report TR89-1 for Jul-Sep 1989. Partial contents include: Induction of marrow hypoxia by radioprotective agents; Cell-cycle radiation response: Role of intracellular factors; Characteristics of radiation-induced performance changes in bar-press avoidance with and without a preshock warning cue; Norepinephrine-induced phosphorylation of a 25 kd phosphoprotein in rat aorta is altered in intraperitoneal sepsis; Quantitative measurement of radiation-induced base products in DNA using gas chromatography-mass spectrometry; Tropism of canine neutrophils to xanthine oxidase; Effects of acute sublethal gamma radiation exposure on aggressive behavior in male mice: A dose-response study; Progressive behavioral changes during the maturation of rats with early radiation-induced hypoplasia of fascia dentata granule cells; Stomach nodules in pigeons; An assessment of the behavioral toxicity of high-energy iron particles compared to other qualities of radiation; L-leucyl-L-leucine methyl ester treatment of canine marrow and peripheral blood cells; Localization of cyclo-oxygenase and prostaglandin E2 in the secretory granule of the mast cell; Radioprotection of mice with interleukin-1: Relationship to the number of spleen colony-forming units; Survival after total-body irradiation. I. Effects of partial small-bowel shielding; Laboratory x-ray irradiator for cellular radiobiology research studies: Dosimetry report.

  5. Gruusia loeb kokku venelaste jäetud pomme ja sõjaohvreid / Liisi Poll

    Poll, Liisi, 1980-


    Vene vägede lahkumist ootavas Gruusias loetakse kokku sõjakaotusi, milleks on inimkaotused, katkenud kaubandus, purustatud infrastruktuur, mahajäetud lõhkekehad. Punase Risti hinnangust sõjapõgenike kohta. Vt. samas: Vene väed lahkuvad endiselt vaid teoreetiliselt

  6. Profil de l'etudiant du premier cycle des etudes medicales de Lome ...

    Profil de l'etudiant du premier cycle des etudes medicales de Lome et sa perception de l'enseignement de l'anatomie. ... Journal de la Recherche Scientifique de l'Universite de Lome ... aux différentes questions des paramètres étudiés.

  7. High value of the radiobiological parameter Dq correlates to expression of the transforming growth factor beta type II receptor in a panel of small cell lung cancer cell lines

    Hougaard, S; Krarup, M; Nørgaard, P;


    Our panel of SCLC cell lines have previously been examined for their radiobiological characteristics and sensitivity to treatment with TGF beta 1. In this study we examined the possible correlations between radiobiological parameters and the expression of the TGF beta type II receptor (TGF beta-r...... role for the repair of radiation induced DNA damage in SCLC....

  8. Radiobiology of hypofractionated stereotactic radiotherapy: what are the optimal fractionation schedules?

    Shibamoto, Yuta; Miyakawa, Akifumi; Otsuka, Shinya; Iwata, Hiromitsu


    In hypofractionated stereotactic radiotherapy (SRT), high doses per fraction are usually used and the dose delivery pattern is different from that of conventional radiation. The daily dose is usually given intermittently over a longer time compared with conventional radiotherapy. During prolonged radiation delivery, sublethal damage repair takes place, leading to the decreased effect of radiation. In in vivo tumors, however, this decrease in effect may be counterbalanced by rapid reoxygenation. Another issue related to hypofractionated SRT is the mathematical model for dose evaluation and conversion. The linear–quadratic (LQ) model and biologically effective dose (BED) have been suggested to be incorrect when used for hypofractionation. The LQ model overestimates the effect of high fractional doses of radiation. BED is particularly incorrect when used for tumor responses in vivo, since it does not take reoxygenation into account. Correction of the errors, estimated at 5–20%, associated with the use of BED is necessary when it is used for SRT. High fractional doses have been reported to exhibit effects against tumor vasculature and enhance host immunity, leading to increased antitumor effects. This may be an interesting topic that should be further investigated. Radioresistance of hypoxic tumor cells is more problematic in hypofractionated SRT, so trials of hypoxia-targeted agents are encouraged in the future. In this review, the radiobiological characteristics of hypofractionated SRT are summarized, and based on the considerations, we would like to recommend 60 Gy in eight fractions delivered three times a week for lung tumors larger than 2 cm in diameter. PMID:27006380

  9. Characteristic 8 keV X rays possess radiobiological properties of higher-LET radiation.

    Shridhar, Ravi; Estabrook, William; Yudelev, Mark; Rakowski, Joseph; Burmeister, Jay; Wilson, George D; Joiner, Michael C


    Electronic brachytherapy systems are being developed that can deliver X rays of varying energy depending on the material of a secondary target. A copper target produces characteristic 8 keV X rays. Our aim was to determine whether 8 keV X rays might deliver greater biological effectiveness than megavoltage photons. Cells of the U251 human glioma cell line were used to compare the biological effects of 8 keV X rays and (60)Co gamma rays in terms of relative biological effectiveness (RBE), oxygen enhancement ratio (OER), and DNA damage. The RBE at 50% and 10% survival was 2.6 and 1.9, respectively. At 50% survival, the OER for cells treated with 8 keV X rays was 1.6 compared with 3.0 for (60)Co gamma rays. The numbers of H2AX foci per Gy after treatment with 8 keV X rays and (60)Co gamma rays were similar; however, the size of the foci generated at 8 keV was significantly larger, possibly indicating more complex DNA damage. The mean area of H2AX foci generated by 8 keV X rays was 0.785 microm(2) (95% CI: 0.756-0.814) compared with 0.491 microm(2) (95% CI: 0.462-0.520) for (60)Co gamma rays (P X rays produce two to three times the biological effectiveness of megavoltage photons, with a radiobiological profile similar to higher-LET radiations.

  10. [Observation of radiobiological characteristics in a HepG2 cell line with mitochondrial DNA deletion].

    Sun, Hengwen; Pan, Yi; Zeng, Zijun; Fang, Liangyi; Zhang, Hongdan; Xie, Songxi; Li, Weixiong; Xu, Jiabin


    To study the radiobiological characteristics of a HepG2 cell line with mitochondrial DNA (mtDNA) deletion. HepG2 cells were cultured in a medium containing ethidium bromide, acetylformic acid and uracil. The HepG2 cell line with mtDNA deletion (ρ(0)HepG2 cells) were acquired after 30 subcultures by limited dilution cloning. The cell survival was then observed in the absence of acetylformic acid and uracil, and the total mtDNA deletion in the cells was confirmed by PCR. The radiosensitivity of HepG2 and ρ(0)HepG2 cells was evaluated by exposure to gradient doses of 6 MV X ray irradiation. The cell apoptosis was assessed following a 2 Gy X-ray exposure with Hochest33342 staining, and the invasiveness of ρ(0)HepG2 cells was measured by Transwell assay. HepG2 cells could survive 30 subcultures in the presence of ethidium bromide, and massive cell death occurred after removal of acetylformic acid and uracil from the medium. PCR confirmed total mtDNA deletion from ρ(0)HepG2 cells, whose α/β value was significantly lower than that of HepG2 cells. ρ(0)Hep-G2 cells showed an obviously lowered cell apoptosis rate following X-ray exposure with enhanced cell invasiveness. HepG2 cells can be induced by ethidium bromide into ρ(0)HepG2 cells with an increased radiation resistance, anti-apoptosis ability and cell invasiveness.

  11. Etude aerodynamique d'un jet turbulent impactant une paroi concave

    LeBlanc, Benoit

    Etant donne la demande croissante de temperatures elevees dans des chambres de combustion de systemes de propulsions en aerospatiale (turbomoteurs, moteur a reaction, etc.), l'interet dans le refroidissement par jets impactant s'est vu croitre. Le refroidissement des aubes de turbine permet une augmentation de temperature de combustion, ce qui se traduit en une augmentation de l'efficacite de combustion et donc une meilleure economie de carburant. Le transfert de chaleur dans les au bages est influence par les aspects aerodynamiques du refroidissement a jet, particulierement dans le cas d'ecoulements turbulents. Un manque de comprehension de l'aerodynamique a l'interieur de ces espaces confinees peut mener a des changements de transfert thermique qui sont inattendus, ce qui augmente le risque de fluage. Il est donc d'interet pour l'industrie aerospatiale et l'academie de poursuivre la recherche dans l'aerodynamique des jets turbulents impactant les parois courbes. Les jets impactant les surfaces courbes ont deja fait l'objet de nombreuses etudes. Par contre des conditions oscillatoires observees en laboratoire se sont averees difficiles a reproduire en numerique, puisque les structures d'ecoulements impactants des parois concaves sont fortement dependantes de la turbulence et des effets instationnaires. Une etude experimentale fut realisee a l'institut PPRIME a l'Universite de Poitiers afin d'observer le phenomene d'oscillation dans le jet. Une serie d'essais ont verifie les conditions d'ecoulement laminaires et turbulentes, toutefois le cout des essais experimentaux a seulement permis d'avoir un apercu du phenomene global. Une deuxieme serie d'essais fut realisee numeriquement a l'Universite de Moncton avec l'outil OpenFOAM pour des conditions d'ecoulement laminaire et bidimensionnel. Cette etude a donc comme but de poursuivre l'enquete de l'aerodynamique oscillatoire des jets impactant des parois courbes, mais pour un regime d'ecoulement transitoire, turbulent

  12. The study of some thiazinic and indaminic dye syntheses induced by ionising radiation; Etude de quelques syntheses de colorants thianziniques et indaminiques amorcees par les rayonnements ionisants

    Balestic, S. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    With a view to finding some radiochemical reactions applicable on an industrial scale for evaluating the radioactive waste from nuclear reactors, a systematic study was made of the radiochemical synthesis of thiazinic dyes such as methylene blue and Lauths' violet, on which the first tests were carried out in 1954. The first part of the study concerned the identification and the dosage, during radiolysis, of dyes by means of their absorption spectra after separation from the reaction medium by adsorption chromatography or ion-exchange; other radiolysis products such as ammonium chloride and hydrogen peroxide were also identified. During a later stage by systematically varying the physico-chemical parameters it was possible to determine the most favourable conditions for radio-synthesis; the maximum radiochemical yields obtained had the following values: G (Lauths' violet) 1,65; G (Methylene blue) = 1,75. Furthermore, the study of the influence of variously substituted aminated products on the radiochemical yield showed the possibility of synthesising Bindsehedlers green and Wursters blue by radiochemical methods. Finally the discovery of a fundamental intermediate product, Wursters red, together with the kinetic study of the chemical synthesis of methylene blue made it possible to determine the main stages of the reaction mechanism and to decide which of these stages could be attributed to ionising radiations in the case of the radiochemical synthesis. (author) [French] Dans le but de trouver des reactions radiochimiques susceptibles d'une application industrielle pour valoriser les dechets radioactifs provenant des reacteurs nucleaires, il a ete entrepris une etude systematique de la synthese radiochimique des colorants thiazimiques tels que le Bleu de Methylene et le Violet de Lauth dont les premiers essais ont ete effectues par Loiseleur en 1954. La premiere partie de l'etude a porte sur l'identification et le dosage des colorants formes

  13. Radiobiologic comparison of helical tomotherapy, intensity modulated radiotherapy, and conformal radiotherapy in treating lung cancer accounting for secondary malignancy risks

    Komisopoulos, Georgios [Department of Medical Physics, Medical School, University of Patras, Patras (Greece); Mavroidis, Panayiotis, E-mail: [Department of Radiation Oncology, University of Texas Health Sciences Center at San Antonio, San Antonio, TX (United States); Department of Medical Radiation Physics, Karolinska Institutet and Stockholm University, Stockholm (Sweden); Rodriguez, Salvador; Stathakis, Sotirios; Papanikolaou, Nikos [Department of Radiation Oncology, University of Texas Health Sciences Center at San Antonio, San Antonio, TX (United States); Nikiforidis, Georgios C.; Sakellaropoulos, Georgios C. [Department of Medical Physics, Medical School, University of Patras, Patras (Greece)


    The aim of the present study is to examine the importance of using measures to predict the risk of inducing secondary malignancies in association with the clinical effectiveness of treatment plans in terms of tumor control and normal tissue complication probabilities. This is achieved by using radiobiologic parameters and measures, which may provide a closer association between clinical outcome and treatment delivery. Overall, 4 patients having been treated for lung cancer were examined. For each of them, 3 treatment plans were developed based on the helical tomotherapy (HT), multileaf collimator-based intensity modulated radiation therapy (IMRT), and 3-dimensional conformal radiation therapy (CRT) modalities. The different plans were evaluated using the complication-free tumor control probability (p{sub +}), the overall probability of injury (p{sub I}), the overall probability of control/benefit (p{sub B}), and the biologically effective uniform dose (D{sup ¯¯}). These radiobiologic measures were used to develop dose-response curves (p-D{sup ¯¯} diagram), which can help to evaluate different treatment plans when used in conjunction with standard dosimetric criteria. The risks for secondary malignancies in the heart and the contralateral lung were calculated for the 3 radiation modalities based on the corresponding dose-volume histograms (DVHs) of each patient. Regarding the overall evaluation of the different radiation modalities based on the p{sub +} index, the average values of the HT, IMRT, and CRT are 67.3%, 61.2%, and 68.2%, respectively. The corresponding average values of p{sub B} are 75.6%, 70.5%, and 71.0%, respectively, whereas the average values of p{sub I} are 8.3%, 9.3%, and 2.8%, respectively. Among the organs at risk (OARs), lungs show the highest probabilities for complications, which are 7.1%, 8.0%, and 1.3% for the HT, IMRT, and CRT modalities, respectively. Similarly, the biologically effective prescription doses (D{sub B}{sup ¯¯}) for the

  14. Modeling detector response in solid-state systems for radiation therapy and radiobiology

    Hugtenburg, R.P. [School of Physics and Astronomy, University of Birmingham, B15 2TT, UK (United Kingdom); Bradley, D.A. [Department of Physics, University of Surrey, Guildford, GU2 7XH, UK (United Kingdom)


    -filled proportional counters (TEPC) where it is anticipated that intercomparisons with experiment will help to validate the use of such codes for the microdosimetry predictions on the sub-cellular scale in radiobiological systems. Monte Carlo based microdosimetry calculations are also expected to assist in explaining LET dependencies found in many solid-state detector systems. (Author)

  15. Three-dimensional radiobiological dosimetry of kidneys for treatment planning in peptide receptor radionuclide therapy

    Baechler, Sebastien; Hobbs, Robert F.; Boubaker, Ariane; Buchegger, Franz; He Bin; Frey, Eric C.; Sgouros, George [Institute of Radiation Physics, Lausanne University Hospital, 1007 Lausanne (Switzerland); Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21231 (United States); Department of Nuclear Medicine, Lausanne University Hospital, 1011 Lausanne (Switzerland); Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21231 (United States)


    Purpose: Peptide receptor radionuclide therapy (PRRT) delivers high absorbed doses to kidneys and may lead to permanent nephropathy. Reliable dosimetry of kidneys is thus critical for safe and effective PRRT. The aim of this work was to assess the feasibility of planning PRRT based on 3D radiobiological dosimetry (3D-RD) in order to optimize both the amount of activity to administer and the fractionation scheme, while limiting the absorbed dose and the biological effective dose (BED) to the renal cortex. Methods: Planar and SPECT data were available for a patient examined with {sup 111}In-DTPA-octreotide at 0.5 (planar only), 4, 24, and 48 h post-injection. Absorbed dose and BED distributions were calculated for common therapeutic radionuclides, i.e., {sup 111}In, {sup 90}Y and {sup 177}Lu, using the 3D-RD methodology. Dose-volume histograms were computed and mean absorbed doses to kidneys, renal cortices, and medullae were compared with results obtained using the MIRD schema (S-values) with the multiregion kidney dosimetry model. Two different treatment planning approaches based on (1) the fixed absorbed dose to the cortex and (2) the fixed BED to the cortex were then considered to optimize the activity to administer by varying the number of fractions. Results: Mean absorbed doses calculated with 3D-RD were in good agreement with those obtained with S-value-based SPECT dosimetry for {sup 90}Y and {sup 177}Lu. Nevertheless, for {sup 111}In, differences of 14% and 22% were found for the whole kidneys and the cortex, respectively. Moreover, the authors found that planar-based dosimetry systematically underestimates the absorbed dose in comparison with SPECT-based methods, up to 32%. Regarding the 3D-RD-based treatment planning using a fixed BED constraint to the renal cortex, the optimal number of fractions was found to be 3 or 4, depending on the radionuclide administered and the value of the fixed BED. Cumulative activities obtained using the proposed simulated

  16. Clinical radiobiology of glioblastoma multiforme. Estimation of tumor control probability from various radiotherapy fractionation schemes

    Pedicini, Piernicola [I.R.C.C.S.-Regional-Cancer-Hospital-C.R.O.B, Unit of Nuclear Medicine, Department of Radiation and Metabolic Therapies, Rionero-in-Vulture (Italy); Department of Radiation and Metabolic Therapies, I.R.C.C.S.-Regional-Cancer-Hospital-C.R.O.B, Unit of Radiotherapy, Rionero-in-Vulture (Italy); Fiorentino, Alba [Sacro Cuore - Don Calabria Hospital, Radiation Oncology Department, Negrar, Verona (Italy); Simeon, Vittorio [I.R.C.C.S.-Regional-Cancer-Hospital-C.R.O.B, Laboratory of Preclinical and Translational Research, Rionero-in-Vulture (Italy); Tini, Paolo; Pirtoli, Luigi [University of Siena and Tuscany Tumor Institute, Unit of Radiation Oncology, Department of Medicine Surgery and Neurological Sciences, Siena (Italy); Chiumento, Costanza [Department of Radiation and Metabolic Therapies, I.R.C.C.S.-Regional-Cancer-Hospital-C.R.O.B, Unit of Radiotherapy, Rionero-in-Vulture (Italy); Salvatore, Marco [I.R.C.C.S. SDN Foundation, Unit of Nuclear Medicine, Napoli (Italy); Storto, Giovanni [I.R.C.C.S.-Regional-Cancer-Hospital-C.R.O.B, Unit of Nuclear Medicine, Department of Radiation and Metabolic Therapies, Rionero-in-Vulture (Italy)


    The aim of this study was to estimate a radiobiological set of parameters from the available clinical data on glioblastoma (GB). A number of clinical trial outcomes from patients affected by GB and treated with surgery and adjuvant radiochemotherapy were analyzed to estimate a set of radiobiological parameters for a tumor control probability (TCP) model. The analytical/graphical method employed to fit the clinical data allowed us to estimate the intrinsic tumor radiosensitivity (α), repair capability (b), and repopulation doubling time (T{sub d}) in a first phase, and subsequently the number of clonogens (N) and kick-off time for accelerated proliferation (T{sub k}). The results were used to formulate a hypothesis for a scheduleexpected to significantly improve local control. The 95 % confidence intervals (CI{sub 95} {sub %}) of all parameters are also discussed. The pooled analysis employed to estimate the parameters summarizes the data of 559 patients, while the studies selected to verify the results summarize data of 104 patients. The best estimates and the CI{sub 95} {sub %} are α = 0.12 Gy{sup -1} (0.10-0.14), b = 0.015 Gy{sup -2} (0.013-0.020), α/b = 8 Gy (5.0-10.8), T{sub d} = 15.4 days (13.2-19.5), N = 1 . 10{sup 4} (1.2 . 10{sup 3} - 1 . 10{sup 5}), and T{sub k} = 37 days (29-46). The dose required to offset the repopulation occurring after 1 day (D{sub prolif}) and starting after T{sub k} was estimated as 0.30 Gy/day (0.22-0.39). The analysis confirms a high value for the α/b ratio. Moreover, a high intrinsic radiosensitivity together with a long kick-off time for accelerated repopulation and moderate repopulation kinetics were found. The results indicate a substantial independence of the duration of the overall treatment and an improvement in the treatment effectiveness by increasing the total dose without increasing the dose fraction. (orig.) [German] Schaetzung eines strahlenbiologischen Parametersatzes auf der Grundlage klinischer Daten bei

  17. A Monte Carlo study for the calculation of the average linear energy transfer (LET) distributions for a clinical proton beam line and a radiobiological carbon ion beam line.

    Romano, F; Cirrone, G A P; Cuttone, G; Rosa, F Di; Mazzaglia, S E; Petrovic, I; Fira, A Ristic; Varisano, A


    Fluence, depth absorbed dose and linear energy transfer (LET) distributions of proton and carbon ion beams have been investigated using the Monte Carlo code Geant4 (GEometry ANd Tracking). An open source application was developed with the aim to simulate two typical transport beam lines, one used for ocular therapy and cell irradiations with protons and the other for cell irradiations with carbon ions. This tool allows evaluation of the primary and total dose averaged LET and predict their spatial distribution in voxelized or sliced geometries. In order to reproduce the LET distributions in a realistic way, and also the secondary particles' contributions due to nuclear interactions were considered in the computations. Pristine and spread-out Bragg peaks were taken into account both for proton and carbon ion beams, with the maximum energy of 62 MeV/n. Depth dose distributions were compared with experimental data, showing good agreement. Primary and total LET distributions were analysed in order to study the influence of contributions of secondary particles in regions at different depths. A non-negligible influence of high-LET components was found in the entrance channel for proton beams, determining the total dose averaged LET by the factor 3 higher than the primary one. A completely different situation was obtained for carbon ions. In this case, secondary particles mainly contributed in the tail that is after the peak. The results showed how the weight of light and heavy secondary ions can considerably influence the computation of LET depth distributions. This has an important role in the interpretation of results coming from radiobiological experiments and, therefore, in hadron treatment planning procedures.

  18. Radiobiological restrictions and tolerance doses of repeated single-fraction hdr-irradiation of intersecting small liver volumes for recurrent hepatic metastases

    Wust Peter


    Full Text Available Abstract Background To assess radiobiological restrictions and tolerance doses as well as other toxic effects derived from repeated applications of single-fraction high dose rate irradiation of small liver volumes in clinical practice. Methods Twenty patients with liver metastases were treated repeatedly (2 - 4 times at identical or intersecting locations by CT-guided interstitial brachytherapy with varying time intervals. Magnetic resonance imaging using the hepatocyte selective contrast media Gd-BOPTA was performed before and after treatment to determine the volume of hepatocyte function loss (called pseudolesion, and the last acquired MRI data set was merged with the dose distributions of all administered brachytherapies. We calculated the BED (biologically equivalent dose for a single dose d = 2 Gy for different α/β values (2, 3, 10, 20, 100 based on the linear-quadratic model and estimated the tolerance dose for liver parenchyma D90 as the BED exposing 90% of the pseudolesion in MRI. Results The tolerance doses D90 after repeated brachytherapy sessions were found between 22 - 24 Gy and proved only slightly dependent on α/β in the clinically relevant range of α/β = 2 - 10 Gy. Variance analysis showed a significant dependency of D90 with respect to the intervals between the first irradiation and the MRI control (p 90 and the pseudolesion's volume. No symptoms of liver dysfunction or other toxic effects such as abscess formation occurred during the follow-up time, neither acute nor on the long-term. Conclusions Inactivation of liver parenchyma occurs at a BED of approx. 22 - 24 Gy corresponding to a single dose of ~10 Gy (α/β ~ 5 Gy. This tolerance dose is consistent with the large potential to treat oligotopic and/or recurrent liver metastases by CT-guided HDR brachytherapy without radiation-induced liver disease (RILD. Repeated small volume irradiation may be applied safely within the limits of this study.

  19. A Monte Carlo study for the calculation of the average linear energy transfer (LET) distributions for a clinical proton beam line and a radiobiological carbon ion beam line

    Romano, F.; Cirrone, G. A. P.; Cuttone, G.; Di Rosa, F.; Mazzaglia, S. E.; Petrovic, I.; Ristic Fira, A.; Varisano, A.


    Fluence, depth absorbed dose and linear energy transfer (LET) distributions of proton and carbon ion beams have been investigated using the Monte Carlo code Geant4 (GEometry ANd Tracking). An open source application was developed with the aim to simulate two typical transport beam lines, one used for ocular therapy and cell irradiations with protons and the other for cell irradiations with carbon ions. This tool allows evaluation of the primary and total dose averaged LET and predict their spatial distribution in voxelized or sliced geometries. In order to reproduce the LET distributions in a realistic way, and also the secondary particles’ contributions due to nuclear interactions were considered in the computations. Pristine and spread-out Bragg peaks were taken into account both for proton and carbon ion beams, with the maximum energy of 62 MeV/n. Depth dose distributions were compared with experimental data, showing good agreement. Primary and total LET distributions were analysed in order to study the influence of contributions of secondary particles in regions at different depths. A non-negligible influence of high-LET components was found in the entrance channel for proton beams, determining the total dose averaged LET by the factor 3 higher than the primary one. A completely different situation was obtained for carbon ions. In this case, secondary particles mainly contributed in the tail that is after the peak. The results showed how the weight of light and heavy secondary ions can considerably influence the computation of LET depth distributions. This has an important role in the interpretation of results coming from radiobiological experiments and, therefore, in hadron treatment planning procedures.

  20. Contribution to the study of recoil species produced by potassium ferrocyanide neutron irradiation; Contribution a l'etude de la reactivite des especes de recul dans le ferrocyanure de potassium irradie aux neutrons thermiques

    Meriadec Vernier de Byans, B. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    The chemical species produced by potassium ferrocyanide neutron irradiation were separated and identified. The study of their behaviour upon thermal annealing has allowed to establish a scheme of reaction as well as a kinetic treatment of the data. Activation energies are determined in different conditions and the effects of radiation dose, oxygen and water of crystallisation upon the activation energies were studied. Preliminary E.S.R. data and its relevance to the decomposition process is also discussed. (authors) [French] On a separe et identifie les differentes especes chimiques produites par irradiation neutronique de ferrocyanure de potassium. L'etude de leur comportement au cours du recuit thermique a permis l'application de differentes cinetiques et l'etablissement d'un schema de reaction. On a deterrmine la valeur des energies d'activation dans differentes conditions de recuit ainsi que l'influence de la dose de radiations, de l'oxygene et de l'eau de cristallisation sur ces energies. Une serie de mesures de resonance paramagnetique electronique a complete cette etude. (auteurs)

  1. Etude theorique des fluctuations structurales dans les composes organiques a dimensionnalite reduite

    Dumoulin, Benoit

    Les systemes a dimensionnalite reduite constituent maintenant une branche entiere de la physique de la matiere condensee. Cette derniere s'est developpee rapidement au cours des dernieres annees, avec la decouverte des materiaux organiques qui presentent, justement, des proprietes physiques fortement anisotropes. Cette these presente une etude en trois parties de plusieurs composes organiques qui, bien que tres differents du point de vue de leurs compositions chimiques et de leurs proprietes physiques a haute temperature, subissent tous une instabilite structurale a tres basse temperature. De plus, dans chacun des cas, l'instabilite structurale est precedee d'un important regime fluctuatif a partir duquel les proprietes physiques changent de maniere significative. Notre etude suit un ordre chronologique inverse puisque nous nous attardons en premier lieu au cas de composes recemment decouverts: les composes de la famille des (BCPTTF)2X (X = PF6 , AsF6). Ces derniers sont des isolants magnetiques a la temperature ambiante et subissent une instabilite structurale de type spin-Peierls a une temperature appelee TSP. En particulier, nous nous interessons a l'etude des proprietes physiques de ces systemes dans le regime fluctuatif, qui precede cette instabilite. Notre etude theorique nous permet de comprendre en detail comment ces systemes s'approchent de l'instabilite struturale. Dans la seconde partie de cette these, nous etudions le regime fluctuatif (pre-transitionnel) observe experimentalement dans le compose de (TMTTF)2PF6. Ce compose organique, dont la structure s'apparente aux sels de Bechgaard, subit une instabilite de type spin-Peierls a une temperature T SP = 19K. Bien que ce compose possede la particularite d'etre un bon conducteur a la temperature ambiante, il subit une transition de type Mott-Hubbard a une temperature Trho ≈ 220K et devient alors un isolant magnetique, analogue aux composes de la famille des (BCPTTF)2X. Le regime fluctuatif precedant l

  2. DEGRO practical guidelines for radiotherapy of non-malignant disorders. Part I: physical principles, radiobiological mechanisms, and radiogenic risk

    Reichl, Berthold [Hospital Weiden, Department of Radiotherapy and Radiation Oncology, Weiden (Germany); Block, Andreas [Hospital Dortmund, Institute for Medical Radiation Physics and Radiation Protection, Dortmund (Germany); Schaefer, Ulrich [Lippe Hospital, Dept. of Radiotherapy, Lemgo (Germany); Bert, Christoph; Mueller, Reinhold [University Hospitals Erlangen, Dept. of Radiation Oncology, Erlangen (Germany); Jung, Horst [University Hospital Hamburg-Eppendorf, Dept. of Radiotherapy and Radiation Oncology, Hamburg (Germany); Roedel, Franz [University Hospital Goethe-University, Dept. of Radiotherapy and Oncology, Frankfurt am Main (Germany); Collaboration: the German Cooperative Group on Radiotherapy for Benign Diseases (GCG-BD)


    Synopsis of the introductory paragraph of the DEGRO consensus S2e-guideline recommendations for the radiotherapy of benign disorders, including physical principles, radiobiological mechanisms, and radiogenic risk. This work is based on the S2e-guideline recommendations published November 14, 2013. The basic principles of radiation physics and treatment delivery, evaluation of putative underlying radiobiological mechanisms, and the assessment of genetic and cancer risk following low-dose irradiation will be presented. Radiation therapy of benign diseases is performed according to similar physical principles as those governing treatment of malignant diseases in radiation oncology, using the same techniques and workflows. These methods comprise usage of orthovoltage X-ray units, gamma irradiation facilities, linear accelerators (LINACs), and brachytherapy. Experimental in vitro and in vivo models recently confirmed the clinically observed anti-inflammatory effect of low-dose X-irradiation, and implicated a multitude of radiobiological mechanisms. These include modulation of different immunological pathways, as well as the activities of endothelial cells, mono- and polymorphonuclear leukocytes, and macrophages. The use of effective dose for radiogenic risk assessment and the corresponding tumor incidence rate of 5.5 %/Sv are currently controversially discussed. Some authors argue that the risk of radiation-induced cancers should be estimated on the basis of epidemiological data. However, such data are rarely available at present and associated with high variability. Current radiobiological studies clearly demonstrate a therapeutic effectiveness of radiation therapy used to treat benign diseases and implicate various molecular mechanisms. Radiogenic risks should be taken into account when applying radiation treatment for benign diseases. (orig.) [German] Zusammenfassung des einfuehrenden Kapitels der DEGRO-S2e-Leitlinie zur Strahlentherapie gutartiger Erkrankungen

  3. Neutron field produced by 25 MeV deuteron on thick beryllium for radiobiological study; energy spectrum.

    Takada, Masashi; Mihara, Erika; Sasaki, Michiya; Nakamura, Takashi; Honma, Toshihiko; Kono, Koji; Fujitaka, Kazunobu


    Biological data is necessary for estimation of protection from neutrons, but there is a lack of data on biological effects of neutrons for radiation protection. Radiological study on fast neutrons has been done at the National Institute of Radiological Sciences. An intense neutron source has been produced by 25 MeV deuterons on a thick beryllium target. The neutron energy spectrum, which is essential for neutron energy deposition calculation, was measured from thermal to maximum energy range by using an organic liquid scintillator and multi-sphere moderated 3He proportional counters. The spectrum of the gamma rays accompanying the neutron beam was measured simultaneously with the neutron spectrum using the organic liquid scintillator. The transmission by the shield of the spurious neutrons originating from the target was measured to be less than 1% by using the organic liquid scintillator placed behind the collimator. The measured neutron energy spectrum is useful in dose calculations for radiobiology studies.

  4. Brachytherapy optimization using radiobiological-based planning for high dose rate and permanent implants for prostate cancer treatment

    Seeley, Kaelyn; Cunha, J. Adam; Hong, Tae Min


    We discuss an improvement in brachytherapy--a prostate cancer treatment method that directly places radioactive seeds inside target cancerous regions--by optimizing the current standard for delivering dose. Currently, the seeds' spatiotemporal placement is determined by optimizing the dose based on a set of physical, user-defined constraints. One particular approach is the ``inverse planning'' algorithms that allow for tightly fit isodose lines around the target volumes in order to reduce dose to the patient's organs at risk. However, these dose distributions are typically computed assuming the same biological response to radiation for different types of tissues. In our work, we consider radiobiological parameters to account for the differences in the individual sensitivities and responses to radiation for tissues surrounding the target. Among the benefits are a more accurate toxicity rate and more coverage to target regions for planning high-dose-rate treatments as well as permanent implants.

  5. A very thin havar film vacuum window for heavy ions to perform radiobiology studies at the BNL Tandem

    Thieberger, P.; Abendroth, H.; Alessi, J.; Cannizzo, L.; Carlson, C.; Gustavsson, A.; Minty, M.; Snydstrup, L.


    Heavy ion beams from the BNL Tandem Van de Graaff accelerators will be made available for radiobiology studies on cell cultures. Beam energy losses need to be minimized both in the vacuum window and in the air in order to achieve the ranges required for the cells to be studied. This is particularly challenging for ions heavier than iron. The design is presented of a 0.4-inch diameter Havar film window that will satisfy these requirements. Films as thin as 80 microinches were successfully pressure tested. The final thickness to be used may be slightly larger to help in achieving pin hole free windows. We discuss design considerations and present pressure and vacuum test results as well as tests with heavy ion beams.

  6. Manipulation of radiobiological hypoxia in a human melanoma xenograft to exploit the bioreductive cytotoxicity of RSU-1069

    Cole, S.; Stratford, I.J.; Adams, G.E. (Medical Research Council, Harwell (UK). Radiobiological Research Unit)


    RSU-1069 (a 2-nitroimidazole) is known to be an efficient hypoxic cell radiosensitizer and potent cytotoxin for hypoxic cells in murine tumours (Chaplin et al. 1986). The authors demonstrated that the compound is also able to kill human melanoma cells, growing as a xenograft, provided the tumour blood supply is occluded for an hour or more, thereby substantially increasing the proportion of susceptible, hypoxic cells. Pharmacokinetic effects may also contribute to this phenomenon, as the effectiveness of bioreductive cytotoxic agents may increase with prolonged contact times (Stratford et al. 1986b). Hydralazine increased radiobiological hypoxia in the HX118 xenograft but this did not enhance the susceptibility of clonogenic melanoma cells to killing by RSU-1069. (author).

  7. Comparison of the radiobiological effect of carbon ion beam therapy and conventional radiation therapy on cervical cancer.

    Suzuki, Yoshiyuki; Nakano, Takashi; Ohno, Tatsuya; Oka, Kuniyuki


    Little clinical evidence has been provided to show the minimization of radiation resistance of tumors using high linear energy transfer radiation. We therefore investigated the radiobiological and molecular pathological aspects of carbon beam therapy. A total of 27 patients with squamous cell carcinoma (SCC) of the cervix were treated using a carbon beam and 50 control patients with SCC of the cervix using a photon beam. The expression of Ki-67, p53, and p27 proteins before radiotherapy and 5 and 15 days after therapy initiation were investigated using immunohistochemistry. Similar changes were observed in Ki-67 labeling index (LI) and p53 LI during carbon and photon beam therapies. However, for carbon beam therapy, the mean p27 LI significantly decreased from 25.2% before treatment to 18.6% on the 5th day after treatment initiation, followed by a significant increase to 36.1% on the 15th day. In contrast, for photon beam therapy, the p27 LI consistently decreased from the initial 19.9% to 13.7% on the 15th day. Histological effects were observably stronger under carbon than photon beam therapy, though no statistically significant difference was observed (p = 0.07 on the 5th day and p = 0.10 on the 15th day). The changes in p27 LI under carbon beam therapy were significantly different from those under photon beam therapy, which suggests important molecular differences in the radio-biological response between therapies. Further investigation is required to elucidate the clinical relevance of these putative changes and optimize the relative biological effectiveness of carbon beam to X-ray.

  8. Tail's Entropy and dose of critical annihilation: a new view of the problem radiobiological; Entropia de Tsallis y dosis de aniquilacion critica: una nueva vision del problema radiobiologico

    Sotolongo Grau, O.; Rodriguez Perez, D.; Antoranz, J. C.


    The aim of this paper is to present a model based on a minimum radiobiological physical hypotheses containing known models as special cases, allowing to define operations of addition and multiplication dose survival probabilities to fit the experimental data.

  9. Regulatory corpus related to the contamination of food products by radionuclides. Application in France and comparative study with Belgium, United-Kingdom, Switzerland and Norway. Report nr 298; Corpus reglementaires relatifs a la contamination des denrees alimentaires par les radionucleides. Application en France et etude comparative avec la Belgique, Le Royaume-Uni, la Suisse et la Norvege. Rapport no. 298

    Bataille, C.; Crouail, P.


    The first part of this report gives an overview of the international legal context: arrangements of the Codex Alimentarius, standards established by the Codex Alimentarius Committee on food additives and contaminants, recommendations of the International Commission on Radiological Protection, role of the IAEA. The second part presents European regulations: those adopted after the Chernobyl accident, those to be applied in case of a radiological accident. A synthesis of international and European regulations is proposed. The regulations applicable in France are presented (protection of population against hazards of ionizing radiations, application modalities). The other parts of the report present the legal framework, the modalities of food product control, and the post-Chernobyl peculiarities for Belgium, the United Kingdom, Switzerland and Norway. The author finally proposes a synthesis and a comparative analysis

  10. Thermodynamic and structural study of the Zr-Ni-Cr ternary system (Zr<50 at%) and of its equilibria with hydrogen: electrochemical application; Etude thermodynamique et structurale du systeme ternaire Zr-Ni-Cr (Zr<50at%) et de ses equilibres avec l`hydrogene: application electrochimique

    Joubert, J.M.


    In the frame of the research on intermetallic compounds for nickel-hydride battery application, attention is focused on AB{sub 2} alloys so called Laves phases. ZrCr{sub 2}, for example, exhibits a large hydrogen capacity but a too low hydride formation equilibrium pressure for practical application. Moreover, the electrolyte (concentrated potassium hydroxide) involves surface passivation through blocking electrochemical mechanisms. First, the study is devoted to the adjustment of the hydride thermodynamic properties regarded to electrochemical application. This was achieved on ZrCr{sub 2} by substitution of chromium by nickel. In a second part surface properties are modified by the precipitation of secondary phases in equilibrium with the Laves phase. The Zr-Ni-Cr phase diagram has been determined at 1000 deg C in the ZrCr{sub 2}-ZrNi-Ni-Cr region and has revealed large solubility of nickel in C14 and C15 Laves phases as well as equilibrium of these phases with three Zr-Ni intermetallic compounds. The knowledge of this diagram has allowed the synthesis of biphasic alloys where the Laves phase of constant composition is in equilibrium with a secondary phase at variable rate. The study of hydrogenation properties of Laves phases has shown the possibility of adjusting the equilibrium pressure of its hydrides to electrochemical application keeping high hydrogen capacity. The hydrogenation properties of secondary phases were also characterized. Finally, it appeared that secondary phases precipitation with increasing rate in the Laves phase matrix produces a spectacular increase of electrochemical capacities. Such an effect of hydrogen by the modification of the surface in contact with electrolyte and by the diffusion of hydrogen from electrolyte to the Laves through the secondary phase when present. (author)

  11. Contribution to the micrographic study of uranium and its alloys; Contribution a l'etude micrographique de l'uranium et de ses alliages

    Monti, H. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    The present report is the result of research carried out by the radio metallurgy section, to perfect micrographic techniques applicable to the study of samples of irradiated uranium. In the first part of this work, two polishing baths are developed, having the qualities with a minimum of disadvantages inherent in their respective compositions: they are, on the one hand perchloric acid-ethanol mixtures, and on the other hand a phospho-chromic-ethanol bath. In the chapter following, the micrographic attack of uranium is studied. The only satisfactory process is oxidation by cathode bombardment forming epitaxic layers. In the third chapter, an attempt is made to characterise the different surface states of the uranium by dissolution potential measurements and electronic diffraction. In the fourth chapter are given some examples of the application of these techniques to the micrographic study of various uranium alloys. In an appendix, it is shown how the chemical oxidation after phospho-chromic-alcohol polishing allows the different inclusions present in the molten uranium to be distinguished. By X-ray diffraction, uranium monocarbide and mononitride inclusions in particular are characterised. (author) [French] Le present rapport est le resultat de recherches effectuees au service de radiometallurgie pour la mise au point de techniques micrographiques applicables a l'etude d'echantillons d'uranium irradie. Dans la premiere partie de ce travail, nous mettons au point deux bains de polissage qui presentent les qualites inherentes a leur composition respective, avec le minimum d'inconvenients: ce sont d'une part des melanges acide perchlorique-ethanol, et d'autre part un bain phospho-chromique-ethanol. Dans le chapitre suivant, nous etudions l'attaque micrographique de l'uranium. Seul le procede d'oxydation par bombardement cathodique formant des couches epitaxiques, est satisfaisant. Dans le troisieme chapitre, nous essayons

  12. Resonant ionization by laser beams: application to ions sources and to study the nuclear structure of radioactive tellurium isotopes; Ionisation resonante par faisceaux laser: application aux sources d'ions et a l'etude de la structure des noyaux radioactifs de tellure

    Sifi, R


    The radioactive ion beams that are produced through current isotope separators are well separated according to the A mass but not according to the Z parameter. The resonant ionization through laser beams applied to ion sources allows the production of radioactive ion beam in a very selective and efficient way by eliminating the isobaric contamination. The first chapter is dedicated to the resonant ionization by laser beams, we describe the principle, the experimental setting, the lasers used, the ionization schemes and the domain of application. The second chapter deals with the application of resonant ionization to laser ion sources for the production of radioactive ion beams. We present experimental tests performed for getting copper ion beams. Resonant ionization through laser is also used in the spectroscopy experiments performed at the Isolde (isotope separation on-line device) installation in CERN where more than 20 elements are ionized very efficiently. The technique is based on a frequency scanning around the excitation transition of the atoms in order to probe the hyperfine structure. Laser spectroscopy allows the determination of the hyperfine structure as well as the isotopic shift of atoms. In the third chapter the method is applied to the spectroscopy of tellurium atoms. First, we define the 2 parameters on which the extraction is based: charge radius and nuclear moments, then we present several theoretical models that we have used to assess our experimental results. (A.C.)

  13. Evaluation of uncertainties of key neutron parameters of PWR-type reactors with slab fuel, application to neutronic conformity; Determination des incertitudes liees aux grandeurs neutroniques d'interet des reacteurs a eau pressurisee a plaques combustibles et application aux etudes de conformite

    Bernard, D


    The aim of this thesis was to evaluate uncertainties of key neutron parameters of slab reactors. Uncertainties sources have many origins, technologic origin for parameters of fabrication and physical origin for nuclear data. First, each contribution of uncertainties is calculated and finally, a factor of uncertainties is associated to key slab parameter like reactivity, isotherm reactivity coefficient, control rod efficiency, power form factor before irradiation and life-time. This factors of uncertainties were computed by Generalized Perturbations Theory in case of step 0 and by directs calculations in case of irradiation problems. One of neutronic conformity applications was about fabrication and nuclear data targets precision adjustments. Statistic (uncertainties) and deterministic (deviations) approaches were studied. Then, neutronics key slab parameters uncertainties were reduced and so nuclear performances were optimized. (author)

  14. Direct evaluation of radiobiological parameters from clinical data in the case of ion beam therapy: an alternative approach to the relative biological effectiveness.

    Cometto, A; Russo, G; Bourhaleb, F; Milian, F M; Giordanengo, S; Marchetto, F; Cirio, R; Attili, A


    The relative biological effectiveness (RBE) concept is commonly used in treatment planning for ion beam therapy. Whether models based on in vitro/in vivo RBE data can be used to predict human response to treatments is an open issue. In this work an alternative method, based on an effective radiobiological parameterization directly derived from clinical data, is presented. The method has been applied to the analysis of prostate cancer trials with protons and carbon ions.Prostate cancer trials with proton and carbon ion beams reporting 5 year-local control (LC5) and grade 2 (G2) or higher genitourinary toxicity rates (TOX) were selected from literature to test the method. Treatment simulations were performed on a representative subset of patients to produce dose and linear energy transfer distribution, which were used as explicative physical variables for the radiobiological modelling. Two models were taken into consideration: the microdosimetric kinetic model (MKM) and a linear model (LM). The radiobiological parameters of the LM and MKM were obtained by coupling them with the tumor control probability and normal tissue complication probability models to fit the LC5 and TOX data through likelihood maximization. The model ranking was based on the Akaike information criterion.Results showed large confidence intervals due to the limited variety of available treatment schedules. RBE values, such as RBE = 1.1 for protons in the treated volume, were derived as a by-product of the method, showing a consistency with current approaches. Carbon ion RBE values were also derived, showing lower values than those assumed for the original treatment planning in the target region, whereas higher values were found in the bladder. Most importantly, this work shows the possibility to infer the radiobiological parametrization for proton and carbon ion treatment directly from clinical data.

  15. SU-E-T-398: Evaluation of Radiobiological Parameters Using Serial Tumor Imaging During Radiotherapy as An Inverse Ill-Posed Problem

    Chvetsov, A; Sandison, G; Schwartz, J; Rengan, R [University of Washington, Seattle, WA (United States)


    Purpose: Combination of serial tumor imaging with radiobiological modeling can provide more accurate information on the nature of treatment response and what underlies resistance. The purpose of this article is to improve the algorithms related to imaging-based radiobilogical modeling of tumor response. Methods: Serial imaging of tumor response to radiation therapy represents a sum of tumor cell sensitivity, tumor growth rates, and the rate of cell loss which are not separated explicitly. Accurate treatment response assessment would require separation of these radiobiological determinants of treatment response because they define tumor control probability. We show that the problem of reconstruction of radiobiological parameters from serial imaging data can be considered as inverse ill-posed problem described by the Fredholm integral equation of the first kind because it is governed by a sum of several exponential processes. Therefore, the parameter reconstruction can be solved using regularization methods. Results: To study the reconstruction problem, we used a set of serial CT imaging data for the head and neck cancer and a two-level cell population model of tumor response which separates the entire tumor cell population in two subpopulations of viable and lethally damage cells. The reconstruction was done using a least squared objective function and a simulated annealing algorithm. Using in vitro data for radiobiological parameters as reference data, we shown that the reconstructed values of cell surviving fractions and potential doubling time exhibit non-physical fluctuations if no stabilization algorithms are applied. The variational regularization allowed us to obtain statistical distribution for cell surviving fractions and cell number doubling times comparable to in vitro data. Conclusion: Our results indicate that using variational regularization can increase the number of free parameters in the model and open the way to development of more advanced

  16. Contributions a L'etude de Dispositifs D'optique Integree

    Touam, Tahar

    Cette these contient des contributions a l'etude de deux champs du vaste domaine de l'optique integree. A cet effet, nous avons divise notre travail en deux grandes parties:. Dans une premiere partie, nous traitons le probleme de la realisation d'une nouvelle classe de guides d'onde planaires utilisables dans le domaine de longueur d'onde de l'infrarouge moyen (infrarouge thermique), domaine ou l'apparition anticipee de fibres optiques a pertes extremement faibles rendraient fort interessante l'existence de tels guides d'onde planaires. Dans un premier temps, nous presentons une etude analytique originale d'une structure planaire a profil d'indice gradue, suivie d'une analyse d'un guide canal base sur cette structure. Dans un deuxieme temps, nous decrivons le procede de fabrication par pulverisation atomique d'un guide planaire forme d'arseniure de gallium (AsGa) sur du dioxyde de silicium (SiO_2 ), combinaison de materiau compatible avec l'infrarouge moyen. Finalement, nous presentons une etude de conception d'un reseau de surface destine a coupler la lumiere dans un tel guide, les autres methodes traditionnelles de couplage semblant peu appropriees aux environs de lambda = 10 mum. Dans une deuxieme partie, nous traitons le probleme de la jonction Y en optique integree, jonction qui soufre de pertes tres importantes des que l'angle d'ouverture devient interessant pour le concepteur de circuits integres optiques. L'analyse est basee sur la methode numerique dite BPM (Beam Propagation Method; methode de propagation du faisceau) qui fait l'objet d'un bref rappel. Nous poursuivons avec l'etude et l'optimisation d'une nouvelle jonction Y dont l'essence est l'utilisation du phenomene de diffraction a travers trois fentes de phase. Nous obtenons ainsi une tres bonne jonction, separant proprement le faisceau, a une ouverture de 10 degres. Finalement, nous faisons un rappel d'un profil d'indice dit "ideal" pour guides courbes et nous proposons l'utilisation de tels guides

  17. Bio-metric study of pig karyotype; Etude biometrique du caryotype du porc

    Haag, J.; Lacourly, N.; Nizza, P. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    This study has a twofold purpose, the former is to determine the swine karyotype as accurately as possible, the latter is to try and develop a method of automatic classification and to show its possibilities and limits. (authors) [French] Cette etude a un double objet: d'une part, de definir de la facon aussi precise que possible le caryotype du porc et d'autre part, de tenter une methode de classification automatique et d'en montrer les possibilites ainsi que les limites. (auteurs)

  18. High resolution and high precision absorption spectroscopy using high finesse cavities: application to the study of molecules with atmospheric interest; Cavites de haute finesse pour la spectroscopie d'absorption haute sensibilite et haute precision: application a l'etude de molecules d'interet atmospherique

    Motto-Ros, V.


    High finesse cavities are used to measure very weak absorption features. Two different methodologies are investigated and applied to the study of molecules with atmospheric interest. First, Continuous Wave - Cavity Ring Down Spectroscopy (CW-CRDS) is used to study the atmospheric spectra of water vapour in the near infrared range. These measurements are performed for temperature and pressure of atmospheric relevance for DIAL applications (Differential Absorption Lidar). This study, financed by the European Space Agency (ESA), goes with the WALES mission (Water Vapour Lidar Experiment in Space). The experimental setup was conceived in order to control pressure, temperature and relative humidity conditions. A particular attention is done to characterize and describe the spectrometer. Then, measurements of red Oxygen B band are performed to demonstrate the huge performance of Optical Feedback Cavity Enhanced Absorption Spectroscopy (OF-CEAS). The desired optical feedback is obtained by light injection into the high finesse cavity through a glass plate placed inside the cavity and closed to the Brewster angle. We show a measurement dynamical range of 5 orders of magnitude (10{sup -5} to 10{sup -10} /cm) and a sensitivity of 10{sup -10} /cm/{radical} Hz. Also, sampling absorption spectra by the super linear cavity frequency comb allows very precise frequency measurements. This is demonstrated by the determination of Oxygen pressure shifts with an absolute accuracy of around 5 x 10{sup -5} cm{sup -1}/atm. To our knowledge, we provide the highest accuracy ever reported for this parameter. (author)

  19. Study of deuterons induced nuclear reactions on light elements (N, Al and Si): Application to containment materials of radioactive wastes; Etude des reactions nucleaires induites par des deuterons sur des elements legers (N, Al, Si): application aux materiaux de confinement des dechets radioactifs

    Pellegrino, St


    Nuclear reaction analysis is well adapted to the quantification of light element. Profiles of concentration in order to follow elements migration into materials can be undertaken. This technique is used to study the behavior of the future matrices for nuclear waste containment. This technique is isotopic, characterized by a good signal-to-background ratio and a very low detection limit. The probability of a nuclear reaction is linked to a parameter called 'cross section' we have to know in order to carry out quantitative analysis. We have determined excitation curves for nitrogen, aluminium and silicon. These experiments were done with deuterons from 0.5 to 2 MeV. Two methods for the cross section characterization are presented and are in agreement with each other. The second one reduces uncertainty. Data are incorporated in the simulation software SIMNRA. We have compared the results obtained on different samples when we use data in literature or data of the study. We have noticed a great fit improvement with the data of this study. The new cross sections of this work will be integrated in the general data base SIGMABASE. Applications on materials such as Si{sub 3}N{sub 4}, nano-metric powders, WCN and nuclear glass YLaMgSiAlON studied for radioactive waste containment are also presented. (author)

  20. Numerical solution of the Maxwell-Vlasov equations in the periodic regime. Application to the study of isotope separation by ion cyclotron resonance; Resolution numerique des equations de Maxwell-Vlasov en regime periodique. Application a l'etude de la separation isotopique par resonance cyclotron ionique

    Omnes, P


    This work is dedicated to the study of the behaviour of a magnetic confined plasma that is excited by a purely sinusoidal electric current delivered by an antenna. The response of the electrons to the electromagnetic field is considered as linear,whereas the ions of the plasma are represented by a non-relativistic Vlasov equation. In order to avoid transients, the coupled Maxwell-Vlasov equations are solved in a periodic mode and in a bounded domain. An equivalent electric conductivity tensor has been defined, this tensor is a linear operator that links the electric current generated by the movement of the particles to the electromagnetic field. Theoretical considerations can assure the existence and uniqueness of a periodical solution to Vlasov equations and of a solution to Maxwell equations in harmonic mode. The system of equations is periodical and has been solved by using an iterative method. The application of this method to the simulation of a isotopic separation device based on ionic cyclotron resonance has shown that the convergence is reached in a few iterations and that the solution is valid. Furthermore a method based on a finite-volume formulation of Maxwell equations in the time domain is presented. 2 new variables are defined in order to better take into account the Gauss' law and the conservation of the magnetic flux, the new system is still hyperbolic. The parallelization of the process has been successfully realized. (A.C.)

  1. Study of the droplet size of sprays generated by swirl nozzles dedicated to gasoline direct injection: measurement and application of the maximum entropy formalism; Etude de la granulometrie des sprays produits par des injecteurs a swirl destines a l'injection directe essence: mesures et application du formalisme d'entropie maximum

    Boyaval, S.


    This PhD presents a study on a series of high pressure swirl atomizers dedicated to Gasoline Direct Injection (GDI). Measurements are performed in stationary and pulsed working conditions. A great aspect of this thesis is the development of an original experimental set-up to correct multiple light scattering that biases the drop size distributions measurements obtained with a laser diffraction technique (Malvern 2600D). This technique allows to perform a study of drop size characteristics near the injector tip. Correction factors on drop size characteristics and on the diffracted intensities are defined from the developed procedure. Another point consists in applying the Maximum Entropy Formalism (MEF) to calculate drop size distributions. Comparisons between experimental distributions corrected with the correction factors and the calculated distributions show good agreement. This work points out that the mean diameter D{sub 43}, which is also the mean of the volume drop size distribution, and the relative volume span factor {delta}{sub v} are important characteristics of volume drop size distributions. The end of the thesis proposes to determine local drop size characteristics from a new development of deconvolution technique for line-of-sight scattering measurements. The first results show reliable behaviours of radial evolution of local characteristics. In GDI application, we notice that the critical point is the opening stage of the injection. This study shows clearly the effects of injection pressure and nozzle internal geometry on the working characteristics of these injectors, in particular, the influence of the pre-spray. This work points out important behaviours that the improvement of GDI principle ought to consider. (author)

  2. Study of air entrainment in high pressure spray: optics diagnostics and application to the Diesel injection; Etude de l'entrainement d'air dans un spray haute pression: diagnostics optiques et application a l'injection diesel

    Arbeau, A.


    The actual development of the engine must reply to a will of fuel consumption reduction and to norms more and more strict concerning the pollutant emissions. Although the Diesel engines are efficient, the NO{sub x} and particle emissions mainly come from the existence of wealthy fuel zone preventing an optimal combustion. Therefore, the air / fuel mixing preparation, highly controlled by the air entrainment in spray, is essential. In this context, we have developed metrological tools in order to analyse the air entrainment mechanism in a dense spray. The Particle Image Velocimetry (PIV) technique is first applied to a conical spray with an injection pressure less than 100 bars to study the air entrainment in spray. A transfer of the methodologies allows then the characterisation and the understanding of the air entrainment mechanism in high pressure full spray (injection pressure less than 1600 bars) type Diesel one. The influence of injection parameters (injection pressure and back pressure) on the mixing rate is studied. The increase of the injection pressure from 800 to 1600 bars implies an increase of the mixing rate of 60 %. Moreover, the thermodynamic conditions of the ambient air, simulated by the chamber back pressure, widely favours the mixing rate. Actually, this latter increases of 350 % when the chamber back pressure varies from 1 to 7 bars. The experimental results do not follow classical laws of air entrainment in one-phase flow jet with variable density, but are in good agreement with an integral model for air entrainment in an axisymmetric full spray. Finally, the Fluorescence Particle Image Velocimetry (FPIV) is introduced in order to extend the PIV application field in dense two-phase flows. (author)

  3. Experimental study and mechanical modelling of the effects of water-driving in an oil saturated chalk. Application to the petroleum industry; Etude experimentale et modelisation mecanique des effets du balayage a l'eau dans une craie saturee d'huile. Application a l'industrie petroliere

    Mata, C.


    measurements and SEM observation, let us highlight two different contributions to mechanical strength of chalk-: 1) The cohesion due to solid micro-bridges between calcite grains (always present in intact samples); 2) The cohesion due to water capillary menisci (which decreases when the degree of water saturation increases). On these grounds, an elasto-plastic model is proposed is order to explain how contributions are coupled. In this modelling, plastic strain is an hardening parameter while water saturation ratio is a softening one. Applications are developed in order to relate water-driving, stress state and subsidence rate in an oil reservoir configuration. (author)

  4. Numerical modeling of damage and permeability interaction in rocks. Application for the radioactive waste storage in deep galleries; Modelisation numerique du couplage entre l'endommagement et la permeabilite des roches. Application a l'etude des ouvrages de stockage souterrain

    Maleki, K


    The relation between damage and permeability in rocks is a very important subject in industrial applications. It is for example the case of cracks around the radioactive waste storage galleries (EDZ) which can rise considerably the permeability and so make a serious problem for the sealing and the safety of these structures. The same phenomena can occur in the surrounding concrete wall of the nuclear power stations and also in the cracking of the oil-bearing rocks reservoirs. The experimental research on this subject, specially in laboratory G.3S-LMS in Ecole Polytechnique made it possible to determine the orders of damage effect on the permeability change. But a numerical modeling of these phenomena for setting a constitutive behavior law was to be done. This is the principal objective of this thesis. In this project, at first the notion of crack damage is defined. This type of damage is modeled by the disc shaped crack distribution in the 3D space. The disc's geometrical characteristics (radius, direction and opening) obey the statistical distribution laws, depending on the type of loading (compression or extension). The upper and lower limits of the characteristics are fixed according to actual observations, carried out on clay-stone (host rock selected for the realization of an underground research laboratory in Bure). In order to modeling the damage in the porous media, the double porosity concept is considered. A method of homogenization is used to simulate the flow through the network of cracks and porosity. It allows to derive the equivalent permeability of the fractured porous media. The study of the correlations between permeability and damage, obtained by this method for various values of fracture density, made it possible to obtain a relation between permeability and crack damage, for classical types of loading as simple extension and simple compression. To generalize this relation in the case of any specified triaxial loading, the crack damage is

  5. A study of the conformation and stability of nitroxide free radicals; Etude de la conformation et de la stabilite de radicaux libres nitroxydes

    Briere, R. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires


    The first part of this study is an application of nuclear magnetic resonance to the determination of the sign and magnitude of the long range nuclear-electron spin-spin couplings in the free radical nitroxide derived from piperidine. It has been shown that the coupling constants of the protons {gamma} to the nitrogen atom have a pronounced spatial dependence as do the protons in the {beta} position, a point which has not been brought out by previous investigations. Conformational analysis of these compounds has been carried out by measurement of the effect of temperature on the NMR spectra at 310 MHz. The synthesis of di-t-Bu nitroxide labelled with C{sup 13} in the {alpha}-position made possible the unambiguous determination of the corresponding {sup 13}C nuclear-electron spin-spin coupling constant, a parameter which had not previously been measured. The coupling constants measured in the 2,2,6,6-tetramethyl piperidine series could then be attributed to the {sup 13}C atoms in the {beta}-position and their variation related to the conformations of the heterocycles. This constitutes the second part of the work reported here. The final section is devoted to a study of the decomposition of an unstable nitroxide having a hydrogen atom in the p-position. This decomposition is bimolecular and the primary isotope effect shows that the rupture. of the C-H bond is involved. From this one can conclude that a nitroxide is stable when the different groups attached to the nitrogen atom cannot give rise to a decomposition either intra molecularly, if the molecular geometry is suitable, or inter molecularly by dimerisation through attack on a different center of a neighbouring molecule thus leading to a fragmentation or a disproportionation. (author) [French] La premiere partie est une application de la resonance magnetique nucleaire a la determination du signe et de la grandeur des couplages a longue distance dans des radicaux libres nitroxydes piperidiniques. Il est montre que

  6. Radiobiological long-term accumulation of environmental alpha radioactivity in extracted human teeth and animal bones in Malaysia.

    Almayahi, B A; Tajuddin, A A; Jaafar, M S


    In this study, the radiobiological analysis of natural alpha emitters in extracted human teeth and animal bones from Malaysia was estimated. The microdistributions of alpha particles in tooth and bone samples were measured using CR-39 alpha-particle track detectors. The lowest and highest alpha emission rates in teeth in the Kedah and Perak states were 0.0080 ± 0.0005 mBq cm(-2) and 0.061 ± 0.008 mBq cm(-2), whereas those of bones in the Perlis and Kedah states were 0.0140 ± 0.0001 mBq cm(-2) and 0.7700 ± 0.0282 mBq cm(-2), respectively. The average alpha emission rate in male teeth was 0.0209 ± 0.0008 mBq cm(-2), whereas that of female teeth was 0.0199 ± 0.0010 mBq cm(-2). The alpha emission rate in teeth is higher in smokers (0.0228 ± 0.0008 mBq cm(-2)) than in non-smokers (0.0179 ± 0.0008 mBq cm(-2)). Such difference was found statistically significant (p < 0.01).

  7. A radiobiology-based inverse treatment planning method for optimisation of permanent l-125 prostate implants in focal brachytherapy

    Haworth, Annette; Mears, Christopher; Betts, John M.; Reynolds, Hayley M.; Tack, Guido; Leo, Kevin; Williams, Scott; Ebert, Martin A.


    Treatment plans for ten patients, initially treated with a conventional approach to low dose-rate brachytherapy (LDR, 145 Gy to entire prostate), were compared with plans for the same patients created with an inverse-optimisation planning process utilising a biologically-based objective. The ‘biological optimisation’ considered a non-uniform distribution of tumour cell density through the prostate based on known and expected locations of the tumour. Using dose planning-objectives derived from our previous biological-model validation study, the volume of the urethra receiving 125% of the conventional prescription (145 Gy) was reduced from a median value of 64% to less than 8% whilst maintaining high values of TCP. On average, the number of planned seeds was reduced from 85 to less than 75. The robustness of plans to random seed displacements needs to be carefully considered when using contemporary seed placement techniques. We conclude that an inverse planning approach to LDR treatments, based on a biological objective, has the potential to maintain high rates of tumour control whilst minimising dose to healthy tissue. In future, the radiobiological model will be informed using multi-parametric MRI to provide a personalised medicine approach.

  8. Radiation-induced cataract-genesis: pathophysiologic, radiobiological and clinical aspects; Catarate radio-induite: aspects physiopathologiques, radiobiologiques et cliniques

    Belkacemi, Y.; Touboul, E.; Meric, J.B. [Hopital Tenon, Service d' Oncologie-Radiotherapie, 75 - Paris (France); Rat, P.; Warnet, J.M. [Paris-5 Univ., Lab. de Toxicologie, UFR Pharmacie, Unite de Pharmacotoxicologie Cellulaire, Service Pharmacie, 75 (France)


    Cataract-genesis is a widely reported late effect of irradiated crystalline lens. In this review the authors discussed the different aspects of radiation cataract pathogenesis, and the different mechanisms involved in the lens opacification, particularly the epithelium modifications such as epithelial cell death. The authors also reported the influence of radiation exposure on cataract formation following total body irradiation (TBI) and autologous or allogeneic bone marrow transplantation for hematologic malignancies. Moreover, the radiobiological parameters are not studied for the crystalline lens of human. We applied for the first time the linear quadratic (LQ) and biological effective dose (BED) concept to TBI data. The calculated value of {alpha}/{beta} of 1 Gy is in the range of the values reported for the other late responding tissues. The other risk factors for cataract development after TBI such as age, gender, central nervous system boost, long-term steroid therapy and heparin administration are discussed. In terms of cataract or sicca syndrome prevention, numerous compounds have been successfully tested in experimental models or used for the prevention of radiation-induced xerostomia in patients treated for head and neck cancer. However, none of them has been clinically evaluated for ocular radiation late effects prevention. In this report the authors discussed some of the radioprotectors potentially interesting for radiation-induced cataract or sicca syndrome prevention. (author)

  9. 5. German congress on radiation oncology, radiobiology and medical physics. Book of abstracts, DEGRO congress; 5. Deutscher Kongress fuer Radioonkologie, Strahlenbiologie und Medizinische Physik. Abstractband zum DEGRO-Kongress



    The special issue of the journal covers the scientific conference program, encompassing 32 symposia and the invited papers, as well as about 300 scientific papers and posters presented at the congress. Most of the papers of the symposium sessions take a cross-disciplinary approach in discussing the large tumor entities and recent advances on the technical and biological level. Subject clusters are medical and physical quality assurance and radiobiology, CNS, ENT, brachytherapy, and benign tumors. One symposium gathered specialists discussing economic and legal aspects. Further topical fields are foreeseable trends and innovative developments for the treatment of cancer of the prostate, breast, and bronchial tract, or enhanced application of radiochemotherapy, the knowledge and contributions from the field of molecular biology, and new technology, including the new media. (orig./CB) [German] Das wissenschaftliche Programm setzt sich zusammen aus 32 Symposien und jeweils ca. 300 freien Vortraegen und Posterpraestentationen. In den Symposien werden mehrheitlich interdisziplinaer sowohl die grossen Tumorentitaeten als auch technische und biologische Neuerungen vorgestellt. Thematische Schwerpunkte sind die medizinische und physikalische Qualitaetssicherung sowie die Strahlenbiologie, gefolgt von den Themenbereichen ZNS, HNO, Brachytherapie und gutartigen Erkrankungen. Ein Symposium widmet sich Wirtschaftlichkeits- und Rechtsfragen. Weitere zukunftsweisende Themenschwerpunkte sind Innovationen beim Prostata-, Mamma- und Bronchialkarzinom sowie der zunehmende Einsatz der Radiochemotherapie, die Nutzung der Kenntnisse aus der Molekularbiologie und technische Neuerungen inklusive der neuen Medien. (orig.)

  10. L'etude de l'InP et du GaP suite a l'implantation ionique de Mn et a un recuit thermique

    Bucsa, Ioan Gigel

    Cette these est dediee a l'etude des materiaux InMnP et GaMnP fabriques par implantation ionique et recuit thermique. Plus precisement nous avons investigue la possibilite de former par implantation ionique des materiaux homogenes (alliages) de InMnP et GaMnP contenant de 1 a 5 % atomiques de Mn qui seraient en etat ferromagnetique, pour des possibles applications dans la spintronique. Dans un premier chapitre introductif nous donnons les motivations de cette recherche et faisons une revue de la litterature sur ce sujet. Le deuxieme chapitre decrit les principes de l'implantation ionique, qui est la technique utilisee pour la fabrication des echantillons. Les effets de l'energie, fluence et direction du faisceau ionique sur le profil d'implantation et la formation des dommages seront mis en evidence. Aussi dans ce chapitre nous allons trouver des informations sur les substrats utilises pour l'implantation. Les techniques experimentales utilisees pour la caracterisation structurale, chimique et magnetique des echantillons, ainsi que leurs limitations sont presentees dans le troisieme chapitre. Quelques principes theoriques du magnetisme necessaires pour la comprehension des mesures magnetiques se retrouvent dans le chapitre 4. Le cinquieme chapitre est dedie a l'etude de la morphologie et des proprietes magnetiques des substrats utilises pour implantation et le sixieme chapitre, a l'etude des echantillons implantes au Mn sans avoir subi un recuit thermique. Notamment nous allons voir dans ce chapitre que l'implantation de Mn a plus que 1016 ions/cm 2 amorphise la partie implantee du materiau et le Mn implante se dispose en profondeur sur un profil gaussien. De point de vue magnetique les atomes implantes se trouvent dans un etat paramagnetique entre 5 et 300 K ayant le spin 5/2. Dans le chapitre 7 nous presentons les proprietes des echantillons recuits a basses temperatures. Nous allons voir que dans ces echantillons la couche implantee est polycristalline et les

  11. Study of the plasticity and application to metals; Etude de la plasticite et application aux metaux

    Jaoul, B


    This book takes stock of the acquired knowledge in the field of plasticity and rupture of the metals and appeals to the physical analyses of the metallurgical structures (grains, grain boundaries, dislocations, point defects, precipitates) which were new in 1965 and are become, since then, classical. This book is a re-issue of those published in 1965 but stays of current interest. (O.M.)

  12. Initiation of detonation by impact on granular explosives; Contribution a l'etude de la generation de la detonation provoquee par impact sur un explosif

    Bernier, H. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    A good number of experiments have shown up the particular behaviour of granular explosives when they are detonated by barrier transmitted shocks. Similar results can be obtained when the shock is induced by impact. In this case the pressure signal shape applied at the explosive is better known and both its intensity and duration can be varied. By using a mathematical model in which the law of chemical kinetics is a linear function of pressure, and different temperatures are used for solids and gases, it is possible to describe most of the behaviour of detonation initiation in solid granular explosives. (author) [French] De nombreuses etudes experimentales ont montre le comportement particulier des explosifs granulaires lors de la detonation provoquee par choc transmis a travers une barriere. Les memes resultats peuvent etre obtenus lorsque la detonation est engendree par impact. Dans ce cas, la forme du signal de pression induit dans l'explosif est mieux connue, et il est possible d'en faire varier l'intensite et la duree d'application. Un modele mathematique utilisant une loi de cinetique chimique fonction lineaire de la pression et ou les temperatures des etats solide et gazeux pendant la reaction sont differenciees, permet de retrouver la plupart des caracteres specifiques de la generation dans un explosif solide granulaire. (auteur)

  13. AFRRI (Armed Forces Radiobiology Research Institute) Reports, January-March 1985


    stains for cell sorting 56 genesis 213 Anticoagulants long-term hematopoiesis, role :472 granulocytic diffeentiation 56 medullary vs.extramedullary 215...functional ability of the mononuclear and macro- phage progeny of the M-CFC derived from the bone marrow and extra- medullary sources. The point to be...hemopoictic aplasia , the implications vival2’. The exact correlation between giucan’s hemo- and possible applications of glueall treatment are in- poietic

  14. AFRRI (Armed Forces Radiobiology Research Institute) Reports, January, February, March 1987.


    precisely controlled intervals. As shown in the classic experiments of Hodgkin and Huxley ," electrical impulses or action potentials develop in neurons that...Pharmacel 19:425-431, 1981. 6. Hodgkin AL, Huxley AF: A quantitative description of membrane current and its application to conduction and excitation in...prostaglandins and vasoactive intestinal polypeptide (VIP) Jordan E. Warnick 2 and Terry C. Pellmar l ’Physiology Department. Armed Forces

  15. Radiobiological risk estimates of adverse events and secondary cancer for proton and photon radiation therapy of pediatric medulloblastoma

    Brodin, N. Patrik (Radiation Medicine Research Center, Dept. of Radiation Oncology, Rigshospitalet, Univ. of Copenhagen (Denmark); Niels Bohr Inst., Faculty of Sciences, Univ. of Copenhagen (Denmark)), e-mail:; Munck af Rosenschoeld, Per; Aznar, Marianne C.; Vogelius, Ivan R. (Radiation Medicine Research Center, Dept. of Radiation Oncology, Rigshospitalet, Univ. of Copenhagen (Denmark)); Kiil-Berthelsen, Anne (Radiation Medicine Research Center, Dept. of Radiation Oncology, Rigshospitalet, Univ. of Copenhagen (Denmark); Dept. of Clinical Physiology and Nuclear Medicine, Centre of Diagnostic Investigations, Rigshospitalet, Univ. of Copenhagen (Denmark)); Nilsson, Per; Bjoerk-Eriksson, Thomas (Dept. of Oncology, Skaane Univ. Hospital and Lund Univ., Lund (Sweden)); Lannering, Birgitta (Dept. of Paediatric Oncology, The Queen Silvia Children' s Hospital, Gothenburg (Sweden))


    Introduction. The aim of this model study was to estimate and compare the risk of radiation-induced adverse late effects in pediatric patients with medulloblastoma (MB) treated with either three-dimensional conformal radiotherapy (3D CRT), inversely-optimized arc therapy (RapidArc (RA)) or spot-scanned intensity-modulated proton therapy (IMPT). The aim was also to find dose-volume toxicity parameters relevant to children undergoing RT to be used in the inverse planning of RA and IMPT, and to use in the risk estimations. Material and methods. Treatment plans were created for all three techniques on 10 pediatric patients that have been treated with craniospinal irradiation (CSI) at our institution in 2007-2009. Plans were generated for two prescription CSI doses, 23.4 Gy and 36 Gy. Risk estimates were based on childhood cancer survivor data when available and secondary cancer (SC) risks were estimated as a function of age at exposure and attained age according to the organ-equivalent dose (OED) concept. Results. Estimates of SC risk was higher for the RA plans and differentiable from the estimates for 3D CRT at attained ages above 40 years. The risk of developing heart failure, hearing loss, hypothyroidism and xerostomia was highest for the 3D CRT plans. The risks of all adverse effects were estimated as lowest for the IMPT plans, even when including secondary neutron (SN) irradiation with high values of the neutron radiation weighting factors (WR{sub neutron}). Conclusions. When comparing RA and 3D CRT treatment for pediatric MB it is a matter of comparing higher SC risk against higher risks of non-cancer adverse events. Considering time until onset of the different complications is necessary to fully assess patient benefit in such a comparison. The IMPT plans, including SN dose contribution, compared favorably to the photon techniques in terms of all radiobiological risk estimates

  16. In vitro and in vivo studies on radiobiological effects of prolonged fraction delivery time in A549 cells.

    Jiang, Ling; Xiong, Xiao-Peng; Hu, Chao-Su; Ou, Zhou-Luo; Zhu, Guo-Pei; Ying, Hong-Mei


    Intensity-modulated radiation therapy, when used in the clinic, prolongs fraction delivery time. Here we investigated both the in vivoand in vitroradiobiological effects on the A549 cell line, including the effect of different delivery times with the same dose on A549 tumor growth in nude mice. The in vitroeffects were studied with clonogenic assays, using linear-quadratic and incomplete repair models to fit the dose-survival curves. Fractionated irradiation of different doses was given at one fraction per day, simulating a clinical dose-time-fractionation pattern. The longer the interval between the exposures, the more cells survived. To investigate the in vivoeffect, we used sixty-four nude mice implanted with A549 cells in the back legs, randomly assigned into eight groups. A 15 Gy radiation dose was divided into different subfractions. The maximum and minimum tumor diameters were recorded to determine tumor growth. Tumor growth was delayed for groups with prolonged delivery time (40 min) compared to the group receiving a single dose of 15 Gy (Pdelivery time had delayed growth compared to those with a 40 min delivery time [20' (7.5 Gy × 2 F) vs 40' (7.5 Gy × 2 F), P= 0.035; 20' (3 Gy × 5 F) vs 40' (3 Gy × 5 F); P= 0.054; 20' (1.67 Gy × 9 F) vs 40' (1.67 Gy × 9 F), P= 0.028]. A prolonged delivery time decreased the radiobiological effects, so we strongly recommend keeping the delivery time as short as possible.

  17. Dosimetric and radiobiologic comparison of 3D conformal versus intensity modulated planning techniques for prostate bed radiotherapy.

    Koontz, Bridget F; Das, Shiva; Temple, Kathy; Bynum, Sigrun; Catalano, Suzanne; Koontz, Jason I; Montana, Gustavo S; Oleson, James R


    Adjuvant radiotherapy for locally advanced prostate cancer improves biochemical and clinical disease-free survival. While comparisons in intact prostate cancer show a benefit for intensity modulated radiation therapy (IMRT) over 3D conformal planning, this has not been studied for post-prostatectomy radiotherapy (RT). This study compares normal tissue and target dosimetry and radiobiological modeling of IMRT vs. 3D conformal planning in the postoperative setting. 3D conformal plans were designed for 15 patients who had been treated with IMRT planning for salvage post-prostatectomy RT. The same computed tomography (CT) and target/normal structure contours, as well as prescription dose, was used for both IMRT and 3D plans. Normal tissue complication probabilities (NTCPs) were calculated based on the dose given to the bladder and rectum by both plans. Dose-volume histogram and NTCP data were compared by paired t-test. Bladder and rectal sparing were improved with IMRT planning compared to 3D conformal planning. The volume of the bladder receiving at least 75% (V75) and 50% (V50) of the dose was significantly reduced by 28% and 17%, respectively (p = 0.002 and 0.037). Rectal dose was similarly reduced, V75 by 33% and V50 by 17% (p = 0.001 and 0.004). While there was no difference in the volume of rectum receiving at least 65 Gy (V65), IMRT planning significant reduced the volume receiving 40 Gy or more (V40, p = 0.009). Bladder V40 and V65 were not significantly different between planning modalities. Despite these dosimetric differences, there was no significant difference in the NTCP for either bladder or rectal injury. IMRT planning reduces the volume of bladder and rectum receiving high doses during post-prostatectomy RT. Because of relatively low doses given to the bladder and rectum, there was no statistically significant improvement in NTCP between the 3D conformal and IMRT plans.

  18. [RET/PTC Gene Rearrangements in the Sporadic and Radiogenic Thyroid Tumors: Molecular Genetics, Radiobiology and Molecular Epidemiology].

    Ushenkova, L N; Koterov, A N; Biryukov, A P


    A review of molecular genetic, radiobiological and molecular epidemiological studies of gene (chromosome) rearrangements RET/PTC in the cells of the thyroid gland as well as the laws in relation to radiation exposure in vitro, in vivo and human populations identified with them are submitted. The data on the c-RET gene and its chimeric constructs with the gene-donors (RET/PTC rearrangements) are considered. The information about the history of the RET/PTC discovery, their types, carcinogenic potential and specificity both to tumor and non-tumor thyroid disease especially for papillary thyroid carcinoma are provided. The data (seven studies) on the induction of RET/PTC after irradiation of tumor and normal thyroid cells in vitro and mice are reviewed. The mechanisms of RET/PTC induction may be associated with DNA double strand breaks and oxidative stress. Some information (three publications) about the possibility of RET/PTC induction by low doses of radiation with low LET (to 0.1 Gy) is given and it is concluded that their potential evidentiary is generally weak. The achievements in the molecular epidemiology of RET/PTC frequency for exposed and unexposed cohorts are stated. At the same time it is noted that, despite the vast array. of data accumulated from 30 countries of the world and more than 20 years of research, the formed provisions are weakly confirmed statistically and have no base corresponding to the canons of evidence-based medicine. The possibility of use of the RET/PTC presence or their frequencies as markers of the papillary thyroid carcinomas and, specifically, their radiogenic forms, is considered. In the first case the answer may be positive, while in the second, the situation is characterized by uncertainty. Based to the above mentioned we came to a conclusion about the need of a pooled or meta-analysis of the totality of the published data.

  19. Laser-driven particle acceleration for radiobiology and radiotherapy: where we are and where we are going

    Giulietti, Antonio


    Radiation therapy of tumors progresses continuously and so do devices, sharing a global market of about $ 4 billions, growing at an annual rate exceeding 5%. Most of the progress involves tumor targeting, multi-beam irradiation, reduction of damage on healthy tissues and critical organs, dose fractioning. This fast-evolving scenario is the moving benchmark for the progress of the laser-based accelerators towards clinical uses. As for electrons, both energy and dose requested by radiotherapy are available with plasma accelerators driven by lasers in the power range of tens of TW but several issues have still to be faced before getting a prototype device for clinical tests. They include capability of varying electron energy, stability of the process, reliability for medical users. On the other side hadron therapy, presently applied to a small fraction of cases but within an exponential growth, is a primary option for the future. With such a strong motivation, research on laser-based proton/ion acceleration has been supported in the last decade in order to get performances suitable to clinical standards. None of these performances has been achieved so far with laser techniques. In the meantime a rich crop of data have been obtained in radiobiological experiments performed with beams of particles produced with laser techniques. It is quite significant however that most of the experiments have been performed moving bio samples to laser labs, rather moving laser equipment to bio labs or clinical contexts. This give us the measure that laser community cannot so far provide practical devices usable by non-laser people.

  20. Contribution to the study of several chemical hazards in the Centre d'Etudes Nucleaires of Fontenay-aux-Roses; Contribution a l'etude de quelques nuisances chimiques au centre d'etudes nucleaires de Fontenay-aux-Roses

    Megemont, C.; Grau, C. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires


    From the checking of 2750 index cards of hazards, the study relates the distribution of the chemical hazards in the Centre d'Etudes Nucleaires of Fontenay-aux-Roses. Those concerning the greatest number of agents in the Centre are classified according to the categories corresponding to the different conditions of working. Thus, the most important are put forward. Then, the authors rapidly make a review of hazards which may have some special interest because they appear more specific of the nuclear energy or because they are the most frequently noted on the index cards of hazards. The case of the tributylphosphate is studied more precisely. (authors) [French] A partir de l'examen de 2750 fiches de nuisances, l'etude porte sur la repartition des nuisances chimiques au Centre d'Etudes Nucleaires de Fontenay-aux-Roses. Celles qui concernent le plus grand nombre d'agents du Centre sont classees selon les categories correspondant aux differentes conditions de travail. Les plus importantes d'entre elles sont ainsi mises en evidence. | Les auteurs passent ensuite en revue, rapidement, les nuisances qui peuvent presenter un interet particulier soit parce qu'elles semblent plus specifiques de l'Energie Nucleaire, soit parce qu'on les rencontre le plus frequemment sur les fiches de nuisances. Le cas du tributylphosphate est envisage de facon plus detaillee. (auteurs)

  1. Comparative dosimetric and radiobiological assessment among a nonstandard RapidArc, standard RapidArc, classical intensity-modulated radiotherapy, and 3D brachytherapy for the treatment of the vaginal vault in patients affected by gynecologic cancer

    Pedicini, Piernicola, E-mail: [Service of Medical Physics, IRCCS Regional Cancer Hospital (C.R.O.B.), Rionero in Vulture (Italy); Caivano, Rocchina [Service of Medical Physics, IRCCS Regional Cancer Hospital (C.R.O.B.), Rionero in Vulture (Italy); Fiorentino, Alba [U.O. of Radiotherapy, IRCCS Regional Cancer Hospital (C.R.O.B.), Rionero in Vulture (Italy); Strigari, Lidia [Laboratory of Medical Physics and Expert Systems, Regina Elena National Cancer Institute, Rome (Italy); Califano, Giorgia [Service of Medical Physics, IRCCS Regional Cancer Hospital (C.R.O.B.), Rionero in Vulture (Italy); Barbieri, Viviana; Sanpaolo, Piero; Castaldo, Giovanni [U.O. of Radiotherapy, IRCCS Regional Cancer Hospital (C.R.O.B.), Rionero in Vulture (Italy); Benassi, Marcello [Service of Medical Physics, Scientific Institute of Tumors of Romagna IRST, Meldola (Italy); Fusco, Vincenzo [U.O. of Radiotherapy, IRCCS Regional Cancer Hospital (C.R.O.B.), Rionero in Vulture (Italy)


    To evaluate a nonstandard RapidArc (RA) modality as alternative to high-dose-rate brachytherapy (HDR-BRT) or IMRT treatments of the vaginal vault in patients with gynecological cancer (GC). Nonstandard (with vaginal applicator) and standard (without vaginal applicator) RapidArc plans for 27 women with GC were developed to compare with HDR-BRT and IMRT. Dosimetric and radiobiological comparison were performed by means of dose-volume histogram and equivalent uniform dose (EUD) for planning target volume (PTV) and organs at risk (OARs). In addition, the integral dose and the overall treatment times were evaluated. RA, as well as IMRT, results in a high uniform dose on PTV compared with HDR-BRT. However, the average of EUD for HDR-BRT was significantly higher than those with RA and IMRT. With respect to the OARs, standard RA was equivalent of IMRT but inferior to HDR-BRT. Furthermore, nonstandard RA was comparable with IMRT for bladder and sigmoid and better than HDR-BRT for the rectum because of a significant reduction of d{sub 2cc}, d{sub 1cc}, and d{sub max} (p < 0.01). Integral doses were always higher than HDR-BRT, although the values were very low. Delivery times were about the same and more than double for HDR-BRT compared with IMRT and RA, respectively. In conclusion, the boost of dose on vaginal vault in patients affected by GC delivered by a nonstandard RA technique was a reasonable alternative to the conventional HDR-BRT because of a reduction of delivery time and rectal dose at substantial comparable doses for the bladder and sigmoid. However HDR-BRT provides better performance in terms of PTV coverage as evidenced by a greater EUD.

  2. Seminar | Development of a PET Cyclotron Based Irradiation Setup for Proton Radiobiology | 25 June


    Sharif Hasan Mahmoud Ghithan, a Palestinian postdoctoral researcher at the Laboratory of Instrumentation and Experimental Particle Physics (Portugal), will discuss the development of an out-of-yoke irradiation setup using the proton beam from a cyclotron that ordinarily produces radioisotopes for Positron Emission Tomography (PET). The speaker will also discuss possible future use of the results of this research for CERN’s new LEIR biomedical facility. The seminar will be proposed in the framework of a meeting of the CERN Medical Applications Study Group.   25 June, 2 p.m. to 3 p.m. Room 13-2-005 ABSTRACT: In this new irradiation setup, the current from a 20 mm thick aluminum transmission foil is read out by homemade transimpedance electronics, providing online dose information. The main monitoring variables, delivered in real-time, include beam current, integrated charge and dose rate. Hence the dose and integrated current delivered at a given instant to an experimental setu...

  3. RTtxGap: An android radiobiological tool for compensation of radiotherapy treatment interruption

    Yusoff, A. L.; Mohamad, M.; Abdullah, R.; Bhavaraju, V. M. K.; Nik Idris, N. R.


    Treatment interruption is not uncommon in radiotherapy. Common reasons for treatment interruption include machine breakdown, holidays and patient severe radiation reactions. Here RTtxGap, an Android application to assist calculations of compensation for treatment gap, is reported. It uses linear quadratic (LQ) model to calculate the biological effective dose (BED) that is used to solve for treatment gap compensations. Solutions are calculated using BED equation, with consideration for tissue proliferation. The accuracy of results has been verified using LQL Equiv software to be accurate within 1%. Five treatment interruption examples were used to illustrate the capability of the software to calculate the treatment compensation schedules. Solving these examples also illustrates the general consensus regarding compensating for unscheduled treatment interruptions, which ultimately involves balancing the BEDs of tumour and organ at risk. In addition to compensation for treatment gap, RTtxGap can also be used to calculate equivalent total dose in 2-Gy fraction (EQD2), to modify treatment schedule and to calculate alternative dose prescriptions having the same isoeffect.

  4. Transformation of Physical DVHs to Radiobiologically Equivalent Ones in Hypofractionated Radiotherapy Analyzing Dosimetric and Clinical Parameters: A Practical Approach for Routine Clinical Practice in Radiation Oncology

    Zoi Thrapsanioti


    Full Text Available Purpose. The purpose of this study was to transform DVHs from physical to radiobiological ones as well as to evaluate their reliability by correlations of dosimetric and clinical parameters for 50 patients with prostate cancer and 50 patients with breast cancer, who were submitted to Hypofractionated Radiotherapy. Methods and Materials. To achieve this transformation, we used both the linear-quadratic model (LQ model and the Niemierko model. The outcome of radiobiological DVHs was correlated with acute toxicity score according to EORTC/RTOG criteria. Results. Concerning the prostate radiotherapy, there was a significant correlation between RTOG acute rectal toxicity and ( and ( dosimetric parameters, calculated for  Gy. Moreover, concerning the breast radiotherapy there was a significant correlation between RTOG skin toxicity and dosimetric parameter, calculated for both  Gy ( and  Gy (. The new tool seems reliable and user-friendly. Conclusions. Our proposed model seems user-friendly. Its reliability in terms of agreement with the presented acute radiation induced toxicity was satisfactory. However, more patients are needed to extract safe conclusions.

  5. Gamma Knife and LINAC-Based Stereotactic Treatments of Intracranial Targets: Dosimetric and Radiobiological Considerations

    Kendall, Ethan Lee

    The scientific community is interested in furthering the understanding of shock wave structures in water, given its implications in a wide range of applications; from researching how shock waves penetrate unwanted body tissues to studying how humans respond to blast waves. Shock wave research on water has existed for over five decades. Previous studies have investigated the shock response of water at pressures ranging from 1 to 70 GPa using flyer plate experiments. This report differs from previously published experiments in that the water was loaded to shock pressures ranging from 0.36 to 0.70 GPa. The experiment also utilized tap water rather than distilled water as the test sample. Flyer plate experiments were conducted in the Shock Physics Laboratory at Marquette University to determine the structure of shock waves within water. A 12.7 mm bore gas gun fired a projectile made of copper, PMMA, or aluminum at a stationary target filled with tap water. Graphite break pins in a circuit determined the initial projectile velocity prior to coming into contact with the target. A Piezoelectric timing pin (PZT pin) at the front surface of the water sample determined the arrival of the leading wave and a Photon Doppler Velocimeter (PDV) measured particle velocity from the rear surface of the water sample. The experimental results were compared to simulated data from a Eulerian Hydrocode called CTH [1]. The experimental results differed from the simulated results with deviations believed to be from experimental equipment malfunctions. The main hypothesis being that the PZT pin false triggered, resulting in measured lower than expected shock velocities. The simulated results were compared to published data from various authors and was within range.

  6. Etude des phenomenes dynamiques ultrarapides et des caracteristiques impulsionnelles d'emission terahertz du supraconducteur YBCO

    Savard, Stephane

    Les premieres etudes d'antennes a base de supraconducteurs a haute temperature critique emettant une impulsion electromagnetique dont le contenu en frequence se situe dans le domaine terahertz remontent a 1996. Une antenne supraconductrice est formee d'un micro-pont d'une couche mince supraconductrice sur lequel un courant continu est applique. Un faisceau laser dans le visible est focalise sur le micro-pont et place le supraconducteur dans un etat hors-equilibre ou des paires sont brisees. Grace a la relaxation des quasiparticules en surplus et eventuellement de la reformation des paires supraconductrices, nous pouvons etudier la nature de la supraconductivite. L'analyse de la cinetique temporelle du champ electromagnetique emis par une telle antenne terahertz supraconductrice s'est averee utile pour decrire qualitativement les caracteristiques de celle-ci en fonction des parametres d'operation tels que le courant applique, la temperature et la puissance d'excitation. La comprehension de l'etat hors-equilibre est la cle pour comprendre le fonctionnement des antennes terahertz supraconductrices a haute temperature critique. Dans le but de comprendre ultimement cet etat hors-equilibre, nous avions besoin d'une methode et d'un modele pour extraire de facon plus systematique les proprietes intrinseques du materiau qui compose l'antenne terahertz a partir des caracteristiques d'emission de celle-ci. Nous avons developpe une procedure pour calibrer le spectrometre dans le domaine temporel en utilisant des antennes terahertz de GaAs bombarde aux protons H+ comme emetteur et detecteur. Une fois le montage calibre, nous y avons insere une antenne emettrice dipolaire de YBa 2Cu3O7-delta . Un modele avec des fonctions exponentielles de montee et de descente du signal est utilise pour lisser le spectre du champ electromagnetique de l'antenne de YBa 2Cu3O7-delta, ce qui nous permet d'extraire les proprietes intrinseques de ce dernier. Pour confirmer la validite du modele

  7. Radiobiology for eye plaque brachytherapy and evaluation of implant duration and radionuclide choice using an objective function

    Gagne, Nolan L.; Leonard, Kara L.; Rivard, Mark J. [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States)


    %-35% BED benefit over {sup 125}I, whereas {sup 131}Cs produced a 3%-7% BED detriment, independent of P, T, and plaque size. Additionally, corresponding organ at risk physical doses were lowest using {sup 103}Pd in all circumstances. Conclusions: The results suggest that shorter implant durations may correlate with more favorable outcomes compared to 7 day implants when treating small or medium intraocular lesions. The data also indicate that implant duration may be safely reduced if the prescription physical dose is likewise diminished and that {sup 103}Pd offers a substantial radiobiological benefit over {sup 125}I and {sup 131}Cs irrespective of plaque position, implant duration, and tumor size.

  8. The Cuban Institute of Oncology and Radiobiology experience on the beliefs and opinions about digital rectal exam in urological patients

    Isabel García Figueredo


    Full Text Available Resumen OBJETIVO Describir las creencias, los conocimientos y opiniones sobre el examen dígito rectal en un grupo de pacientes urológicos. MÉTODOS Se desarrolló un estudio descriptivo transversal donde se evaluó un cuestionario anónimo con 15 preguntas, dividido en tres bloques: 1 variables socio-demográficas; 2 retraso en ir a la consulta de urología y su inconformidad con la práctica del examen dígito rectal; 3 percepción de dolor y malestar durante el examen dígito rectal. El cuestionario fue aplicado a una muestra de conveniencia. RESULTADOS Se analizaron 84 encuestas aplicadas en el Instituto de Oncología y Radiobiología de Cuba. Los resultados mostraron que 70,24% de los participantes conocían en cierta medida sobre el cáncer de próstata y 64,29%, sobre el uso del antígeno prostático específico. Sólo 27% encontró útil realizarse el examen digito rectal. Los mayores impedimentos para asistir a la consulta del urólogo fueron: no someterse a una biopsia (79,76% y evadir la práctica del examen dígito rectal (66,66%. Además, se observó que 52,39% y 36,90% de los hombres se quejaron de dolor moderado y severo respectivamente, siendo traumático el examen dígito rectal en 61,9%. Sin embargo, 88,09% de los pacientes respondió que repetirían el examen al siguiente año y el 94,05% animaría a un amigo para someterse al él. CONCLUSIONES En la muestra de individuos estudiados, más de la mitad afirmó conocer sobre el cáncer de próstata y el antígeno prostático específico, sin embargo, no consideró provechoso someterse a un examen dígito rectal. Evitar someterse a una biopsia o al examen dígito rectal fueron los principales impedimentos para su asistencia al urólogo. A pesar de que en la mayoría de los pacientes, realizarse el examen dígito rectal fue traumático, estos consintieron en repetírselo en el futuro.

  9. Patient-Specific Dosimetry and Radiobiological Modeling of Targeted Radionuclide Therapy Grant - final report

    George Sgouros, Ph.D.


    The broad, long-term objectives of this application are to 1. develop easily implementable tools for radionuclide dosimetry that can be used to predict normal organ toxicity and tumor response in targeted radionuclide therapy; and 2. to apply these tools to the analysis of clinical trial data in order to demonstrate dose-response relationships for radionuclide therapy treatment planning. The work is founded on the hypothesis that robust dose-response relationships have not been observed in targeted radionuclide therapy studies because currently available internal dosimetry methodologies are inadequate, failing to adequately account for individual variations in patient anatomy, radionuclide activity distribution/kinetics, absorbed dose-distribution, and absorbed dose-rate. To reduce development time the previously available software package, 3D-ID, one of the first dosimetry software packages to incorporate 3-D radionuclide distribution with individual patient anatomy; and the first to be applied for the comprehensive analysis of patient data, will be used as a platform to build the functionality listed above. The following specific aims are proposed to satisfy the long-term objectives stated above: 1. develop a comprehensive and validated methodology for converting one or more SPECT images of the radionuclide distribution to a 3-D representation of the cumulated activity distribution; 2. account for differences in tissue density and atomic number by incorporating an easily implementable Monte Carlo methodology for the 3-D dosimetry calculations; 3. incorporate the biologically equivalent dose (BED) and equivalent uniform dose (EUD) models to convert the spatial distribution of absorbed dose and dose-rate into equivalent single values that account for differences in dose uniformity and rate and that may be correlated with tumor response and normal organ toxicity; 4. test the hypothesis stated above by applying the resulting package to patient trials of targeted

  10. 7. Saturne study meeting; Septiemes journees d`etudes saturne



    This Saturne workshop has welcomed 120 scientists. 3 sessions have been organized: accelerators, physics and miscellaneous. The most recent experiments realized or scheduled at Saturne have been presented and the discussions which followed showed the high scientific interest taken in that equipment and made the participants regret its definitive closing down. Presentations by european teams about existent equipment, machines under construction or new projects opened the way to new perspectives. A lot of contributions were dedicated to the realization of high intensity particle beams and to the applications of accelerators. (A.C.)

  11. Etude comparative de tubes en matériaux composites en vue de l'application à l'exploitation des hydrocarbures en mer profonde Comparative Study of Composite-Material Tubes with a View to Their Use for Deep Offshore Hydrocarbon Production

    Bonavent G.


    Full Text Available Les prévisions de développement de la production pétrolière en mer profonde font apparaître de nouveaux besoins en tubes légers et à haute résistance pour les liaisons verticales entre les têtes de puits sous-marines et les plates-formes flottantes, et les conduites immergées par grand fond. Certains matériaux composites peuvent répondre à ces besoins et présentent en outre l'avantage d'une excellente résistance à la corrosion dans l'environnement marin. Toutefois, les choix sont imposés essentiellement par des contraintes d'ordre mécanique. On cherche ici à comparer, par rapport à l'acier, les avantages de deux types de matériaux composites - les composites acier-résine - les composites fibres-résine dont on résume les principales caractéristiques et les domaines d'applications possibles en fonction des spécifications pétrolières Development forecosts for deep offshore petroleum production bring out new needs for light tubes for vertlcaf linksbetween subsea wellheads and floating piatforms as well as for subsea pipelines ut great depths. Some composite materials moy meet such requirements while also hoving the advantoge of high résistance ta corrosion in a marine environment. However, the choices are mainly governed by stresses of a mechanical nature. Compared with steel, this article seeks ta describe the advantages of the following two types of composite materials : (il steel-resin composites, and (ii fiber-resin composites. The leading properties and the possible arecs of application are summed up as a function of petroleum specifications.

  12. Workstations studies and radiation protection; Etudes de postes et radioprotection

    Lahaye, T. [Direction des relations du travail, 75 - Paris (France); Donadille, L.; Rehel, J.L.; Paquet, F. [Institut de Radioprotection et de Surete Nucleaire, 92 - Fontenay-aux-Roses (France); Beneli, C. [Paris-5 Univ., 75 (France); Cordoliani, Y.S. [Societe Francaise de Radioprotection, 92 - Fontenay-aux-Roses (France); Vrigneaud, J.M. [Assistance Publique - Hopitaux de Paris, 75 (France); Gauron, C. [Institut National de Recherche et de Securite, 75 - Paris (France); Petrequin, A.; Frison, D. [Association des Medecins du Travail des Salaries du Nucleaire (France); Jeannin, B. [Electricite de France (EDF), 75 - Paris (France); Charles, D. [Polinorsud (France); Carballeda, G. [cabinet Indigo Ergonomie, 33 - Merignac (France); Crouail, P. [Centre d' Etude sur l' Evaluation de la Protection dans le Domaine Nucleaire, 92 - Fontenay-aux-Roses (France); Valot, C. [IMASSA, 91 - Bretigny-sur-Orge (France)


    This day on the workstations studies for the workers follow-up, was organised by the research and health section. Devoted to the company doctors, for the competent persons in radiation protection, for the engineers of safety, it presented examples of methodologies and applications in the medical, industrial domain and the research, so contributing to a better understanding and an application of regulatory measures. The analysis of the workstation has to allow a reduction of the exposures and the risks and lead to the optimization of the medical follow-up. The agenda of this day included the different subjects as follow: evolution of the regulation in matter of demarcation of the regulated zones where the measures of workers protection are strengthened; presentation of the I.R.S.N. guide of help to the realization of a workstation study; implementation of a workstation study: case of radiology; the workstation studies in the research area; Is it necessary to impose the operational dosimetry in the services of radiodiagnostic? The experience feedback of a competent person in radiation protection (P.C.R.) in a hospital environment; radiation protection: elaboration of a good practices guide in medical field; the activities file in nuclear power plant: an evaluation tool of risks for the prevention. Methodological presentation and examples; insulated workstation study; the experience feedback of a provider; Contribution of the ergonomics to the determiners characterization in the ionizing radiation exposure situations;The workstations studies for the internal contamination in the fuel cycle facilities and the consideration of the results in the medical follow-up; R.E.L.I.R. necessity of workstation studies; the consideration of the human factor. (N.C.)

  13. Monte Carlo dose calculations and radiobiological modelling: analysis of the effect of the statistical noise of the dose distribution on the probability of tumour control.

    Buffa, F M; Nahum, A E


    The aim of this work is to investigate the influence of the statistical fluctuations of Monte Carlo (MC) dose distributions on the dose volume histograms (DVHs) and radiobiological models, in particular the Poisson model for tumour control probability (tcp). The MC matrix is characterized by a mean dose in each scoring voxel, d, and a statistical error on the mean dose, sigma(d); whilst the quantities d and sigma(d) depend on many statistical and physical parameters, here we consider only their dependence on the phantom voxel size and the number of histories from the radiation source. Dose distributions from high-energy photon beams have been analysed. It has been found that the DVH broadens when increasing the statistical noise of the dose distribution, and the tcp calculation systematically underestimates the real tumour control value, defined here as the value of tumour control when the statistical error of the dose distribution tends to zero. When increasing the number of energy deposition events, either by increasing the voxel dimensions or increasing the number of histories from the source, the DVH broadening decreases and tcp converges to the 'correct' value. It is shown that the underestimation of the tcp due to the noise in the dose distribution depends on the degree of heterogeneity of the radiobiological parameters over the population; in particular this error decreases with increasing the biological heterogeneity, whereas it becomes significant in the hypothesis of a radiosensitivity assay for single patients, or for subgroups of patients. It has been found, for example, that when the voxel dimension is changed from a cube with sides of 0.5 cm to a cube with sides of 0.25 cm (with a fixed number of histories of 10(8) from the source), the systematic error in the tcp calculation is about 75% in the homogeneous hypothesis, and it decreases to a minimum value of about 15% in a case of high radiobiological heterogeneity. The possibility of using the error

  14. Research in radiobiology

    Jee, W.S.S.


    This report discusses the technical progress made during the past year. Good progress has been made in the areas of bones cells at risk, bone cell morphometry, bone cell residence time, microdistribution of plutonium-239, and the calculation of cell-specific radiation dosimetry. 3 figs., 11 tabs. (KJD)

  15. Etude de L'energie Moyenne de Creation de Paire dans les Detecteurs de Particules AU Silicium Amorphe Hydrogene

    Dubeau, Jacques

    Ce travail porte sur la mesure et le calcul de l'energie de creation d'une paire electron-trou, epsilon_{p}, par une particule ionisante dans des detecteurs en couches minces au a-Si:H. Cette etude fut realisee a l'aide de dispositifs specialement concus et qui sont de deux types. Le premier emprunte au domaine des cellules photovoltaiques des structures p/i/n qui ont des couches dopees de ~30 nm mais dont on augmente l'epaisseur de la couche sensible, la couche i, a 3 ou 4 mum. Ces dispositifs peuvent etre polarises en inverse jusqu'a 20 V/ mum. Le second type consiste aussi en des structures p/i/n qui cette fois sont adaptees specialement aux applications de detection. Ces nouveaux dispositifs possedent une couche p de plus de 300 nm qui attenue l'injection d'electrons lors de l'application de la tension inverse, prevenant ainsi le claquage premature et permettant l'application de tensions de plus de 60 V/mum. De plus, ils ont une couche i faisant de 4 a 18 mu m. Nous avons soumis ces dispositifs a des protons et des particules alpha couvrant un domaine de dE/dx de 7.5 a 300 keV/mum. On met ainsi en evidence deux regimes d'operations. Premierement, lorsqu'on utilise des particules ayant des dE/dx eleves, a des incidences normales a la surface du detecteur et que la tension appliquee aux bornes du dispositif est faible, le signal est fortement attenue par des effets plasmas. Deuxiemement, a de fortes tensions pour des particules a incidences obliques et dE/dx faibles, l'amplitude du signal est proportionnelle a l'energie deposee dans la zone i du detecteur. Cependant, ce signal n'est pas sature et il semble augmenter avec la tension au-dela de la tension de claquage. De plus, on demontre qu'a des tensions intermediaires le signal est plus eleve si la tension est pulsee et si le temps d'integration de l'electronique est long (~ 20mus). En extrapolant l'amplitude du signal a une tension infinie nous obtenons une valeur de epsilon _{p} affranchie de tout effet de

  16. Spinal cord response to altered fractionation and re-irradiation: Radiobiological considerations and role of bioeffect models

    Supe Sanjay


    Full Text Available The aim of radiation oncologist is to implement an uncomplicated loco regional control of cancer by radiation therapy. The bioeffect of a physical dose depends on the nature of the tissue, fractionation scheme, dose rate and treatment time. The transformation of absorbed dose into a bioeffect dose is controlled by treatment variables and the radiobiological characteristics of the relevant tissue. Various bioeffect models have been proposed to predict the biological effect of radiotherapy treatments. Dale has proposed extrapolated response dose (ERD equations for external beam therapy, intracavitary brachytherapy and interstitial brachytherapy. Within the context of the LQ model, the parameter which quantifies the overall biological effect on a given tissue is the biologically effective dose (BED which is obtained by applying repopulation correction to ERD (Orton,. Thames proposed the total effect (TE concept based on the incomplete repair LQ model which accounts for the biological effect of a fractionated course of radiotherapy. Spinal cord myelitis limits the dose to tumours in the head and neck, thoracic and upper abdominal regions resulting in reduction of tumour control probability. Radiation myelopathy is one of the most devastating complications of clinical radiotherapy. Treatment techniques that are designed to minimize the risk of spinal cord injury are likely to underdose the tumour consequent failure to control the disease. Since radiation myelopathy results in severe and irreversible morbidity, it is important to establish the tolerance dose of the spinal cord. A number of patients have recently been reported to have developed radiation myelopathy following hyperfractionated accelerated radiotherapy. As the survival rates of patients increase, radiation oncologists are more frequently faced with the problem of treatment of late recurrence or second tumours situated within or close to previously treated site. A rationale for taking a

  17. Etude de la variation de transmission optique dans l'UltraViolet du quartz "Nippon Silica Glass" après expositions à des rayonnements - Etude du système d'acquisition de données et du système de contrôle de Hautes Tensions appliquées aux chambres à fils du BARREL RICH de DELPHI

    Delorme, Sophie


    Etude de la variation de transmission optique dans l'UltraViolet du quartz "Nippon Silica Glass" après expositions à des rayonnements - Etude du système d'acquisition de données et du système de contrôle de Hautes Tensions appliquées aux chambres à fils du BARREL RICH de DELPHI

  18. Etude spectroscopique des noyaux riches en protons dans la region 22 < Z < 28 et T$_(Z)$ < -3/2

    Dossat, Cedric


    La region des noyaux riches en protons tels que 22 < Z < 28 et T$_(Z)$ < -3/2 a pu etre etudiee de maniere tres detaillee grace a trois experiences menees au GANIL entre 1999 et 2002 : cette etude porte sur 23 isotopes allant du $^(39)$Ti au $^(53)$Ni. Nous avons mesure pour la premiere fois les durees de vie du $^(43)$V, du $^(51)$Ni et du $^(51)$Co, et considerablement ameliore la precision de celles deja connues. De nouvelles transitions par emission de protons et de rayonnement $\\gamma$ o...

  19. SU-E-T-275: Radiobiological Evaluation of Intensity Modulated Radiotherapy Treatment for Locally Advanced Head and Neck Squamous Cell Carcinomas

    Rekha Reddy, B.; Ravikumar, M.; Tanvir Pasha, C.R; Anil Kumar, M.R; Varatharaj, C. [Kidwai Memorial Institute of Oncology Bangalore, Karnataka (India); Pyakuryal, A [University Illinois at Chicago, Chicago, IL (United States); Narayanasamy, Ganesh [UTHSCSA, San Antonio, TX (United States)


    Purpose: To evaluate the radiobiological outcome of Intensity Modulated Radiotherapy Treatment (IMRT) for locally advanced head and neck squamous cell carcinomas using HART (Histogram Analysis in Radiation Therapy; J Appl Clin Med Phys 11(1): 137–157, 2010) program and compare with the clinical outcomes. Methods: We have treated 20 patients of stage III and IV HNSCC Oropharynx and hypopharynx with accelerated IMRT technique and concurrent chemotherapy. Delineation of tumor and normal tissues were done using Danish Head and Neck Cancer Group (DAHANCA) contouring guidelines and radiotherapy was delivered to a dose of 70Gy in 35 fractions to the primary and involved lymph nodes, 63Gy to intermediate risk areas and 56 Gy to lower risk areas, Monday to Saturday, 6 Days/week using 6 MV Photons with an expected overall treatment time of 6 weeks. The TCP and NTCP's were calculated from the dose-volume histogram (DVH) statistics using the Poisson Statistics (PS) and JT Lyman models respectively and the Resultwas correlated with clinical outcomes of the patients with mean follow up of 24 months. Results: Using HART program, the TCP (0.89± 0.01) of primary tumor and the NTCP for parotids (0.20±0.12), spinal cord (0.05±0.01), esophagus (0.30±0.2), mandible (0.35±0.21), Oral cavity (0.37±0.18), Larynx (0.30±0.15) were estimated and correlated with clinical outcome of the patients. Conclusion: Accelerated IMRT with Chemotherapy is a clinical feasible option in the treatment of locally advanced HNSCC with encouraging initial tumour response and acceptable acute toxicities. The correlation between the clinical outcomes and radiobiological model estimated parameters using HART programs are found to be satisfactory.

  20. Dosimetric and radiobiological comparison of CyberKnife M6TM InCise multileaf collimator over IRISTM variable collimator in prostate stereotactic body radiation therapy

    Vindu Kathriarachchi


    Full Text Available The impetus behind our study was to establish a quantitative comparison between the IRIS collimator and the InCise multileaf collimator (MLC (Accuray Inc. Synnyvale, CA for prostate stereotactic body radiation therapy (SBRT. Treatment plans for ten prostate cancer patients were performed on MultiPlan™ 5.1.2 treatment planning system utilizing MLC and IRIS for 36.25 Gy in five fractions. To reduce the magnitude of variations between cases, the planning tumor volume (PTV was defined and outlined for treating prostate gland only, assuming no seminal vesicle or ex-capsule involvement. Evaluation indices of each plan include PTV coverage, conformity index (CI, Paddick's new CI, homogeneity index, and gradient index. Organ at risk (OAR dose sparing was analyzed by the bladder wall Dmaxand V37Gy, rectum Dmaxand V36Gy. The radiobiological response was evaluated by tumor control probability and normal tissue complication probability based on equivalent uniform dose. The dose delivery efficiency was evaluated on the basis of planned monitor units (MUs and the reported treatment time per fraction. Statistical significance was tested using the Wilcoxon signed rank test. The studies indicated that CyberKnife M6™ IRIS and InCise™ MLC produce equivalent SBRT prostate treatment plans in terms of dosimetry, radiobiology, and OAR sparing, except that the MLC plans offer improvement of the dose fall-off gradient by 29% over IRIS. The main advantage of replacing the IRIS collimator with MLC is the improved efficiency, determined from the reduction of MUs by 42%, and a 36% faster delivery time.

  1. Preparation and study of dialkyl nitroxide radicals; Preparation et etude de radicaux nitroxydes diacyles

    Chenavas, P. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires


    These radicals are obtained by oxidation of N-hydroxy-imides with lead tetracetate or p-nitro-perbenzoic acid. These imides are prepared by heating dicarboxylic acids anhydrides with benzyloxy-amine followed by catalytic hydrogenation of N-benzyloxy-imides so obtained. Two series of radicals have mainly been studied, the first concerning five-membered cyclic imides, the second six-membered cyclic imides, these molecules having methyls substituents or no on the carbon ring. N. M. R. spectra of some O-benzyl-imides have been analysed. These different results have made it possible to study the conformation and stereochemistry of these imides. (author) [French] Ces radicaux sont obtenus par oxydation d'imides N-hydroxyles par le tetracetate de plomb ou l'acide p-nitroperbenzoique; ces imides sont prepares par chauffage d'anhydrides de diacides en presence de benzyloxyamine suivie d'une hydrogenation catalytique des N-benzyloxyimides ainsi obtenus. Deux series de radicaux ont principalement ete etudies: la premiere relative a des imides cycliques a cinq chainons, la seconde a des imides cycliques a six chainons, ces molecules ayant des substituants methyles ou non sur la chaine carbonee. Les derives O-benzyles de quelques-uns de ces imides ont ete analyses en R. M. N. Ces differents resultats ont permis une etude de la conformation et de la stereochimie de ces imides. (auteur)

  2. Alecto 2 - interaction studies; Alecto 2 - etudes d'interaction

    Brunet, J.P.; Clouet d' Orval, Ch.; Mougniot, J.C.; Penet, F. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    Weak interactions were experimentally studies with the tank of the critical assembly Alecto II and one, two or three bottles containing solutions of various concentrations. In particular, was studied the validity of certain classical assumptions, shielding effects, screening and semi-reflexion effects, importance of thermal coupling. The method of the 'k{sub eff}, solid angle' is shown to apply to such a system. The determination by divergence and pulsed neutron technique of the reactivity related to a millimeter of solution level affords the obtention of critical heights in terms of reactivity. (authors) [French] Une etude experimentale d'interactions faibles a ete faite entre la cuve de l'experience critique ALECTO II et une, deux ou trois bouteilles contenant des concentrations variees. On etudie, en particulier, la validite de certaines hypotheses classiques, effets d'ombre, d'ecrans, de semi-reflexion, importance du couplage thermique. On montre d'autre part que la methode du 'K{sub eff}, angle solide' peut s'appliquer a un tel systeme. La determination par divergence et neutrons pulses de la reactivite liee au millimetre de solution permet de traduire les hauteurs critiques obtenues, en terme de reactivite. (auteurs)

  3. 练习曲中的童话画面%The Fairy Tale Pictures in Etudes



    The two sets of Etudes-Tableaux op33 and op39 are the most important and most repre- sentative works in Rachmaninoff's piano music as well as a perfect eornbination of art and technique. Selecting the well-known and most representative op39no6 Little Red Riding Hood and the Wolf, this paper analyses the visualization of pictures from the music and its playing techniques, hoping to shed light on its performance and teaching.%音画练习曲op33和op39是拉赫玛尼诺夫钢琴音乐创作中最重要且最具代表性的作品之一.也是艺术性和技术性的完美结合体。选取著名的并最有代表性的op39n06《小红帽与野狼》,从音乐的画面性和演奏的技巧性两方面进行分析,以期在演奏与教学方面得到启发。

  4. Etude morphologique des poudres. Applications au titanate de baryum et à l'alumine

    Prod'Homme, M.; Chermant, L.; Coster, M.; Chermant, J. L.


    In this paper, we specially looked to the study of shape of particles and aggregates of BaTiO3 and AI2O3 powders with very different physico-chemical features in order to characterize morphologically pulverulent media. Although the analysis of the shape may be carried out on two different scales, providing access either to the silhouette or to the roughness of particles or aggregates, only the investigation of the silhouette has been approached as a first step. For that purpose a number of shape factors was selected and correlations were looked for by statistical analysis. Dans cet article, nous nous sommes penchés plus particulièrement sur l'étude de la forme de particules et d'agrégats de poudres BaTiO3 et AI2O3, présentant des caractéristiques physico-chimiques très différentes, dans le but de caractériser morphologiquement des milieux pulvérulents. Bien que l'analyse de la forme puisse s'effectuer à deux échelles différentes permettant d'accéder, soit à la silhouette, soit à la rugosité des particules ou des agrégats, nous n'avons abordé ici, dans un premier temps, que l'étude de la silhouette. Nous avons pour cela sélectionné un certain nombre d'indices de forme et recherché des corrélations par analyse statistique.

  5. Etude des etats electroniques en champ magnetique dans le niveau de Landau N=0 de la tricouche ABC de graphene

    Rondeau, Maxime

    Dans cet ouvrage nous etudions les phases du gaz d'electrons bidimensionnel dans la tricouche de graphene en empilement ABC. En partant du modele des liaisons fortes et en faisant l'approximation du continuum autour des vallees K +, K-, nous obtenons un modele effectif a deux bandes qui permet de decrire la physique de basse energie des electrons en champ magnetique dans cette structure. Ce modele contient trois orbitales degenerees dans le niveau de Landau N = O. Ce dernier est donc 12N φ, fois degeneres en incluant les degres de liberte de spin et de vallee. En ajoutant l'interaction de Coulomb au systeme et en considerant seulement les remplissages v = -5, -4, -4, 5 afin d'avoir un systeme a trois niveaux, nous etudions le diagramme de phase du gaz d'electrons en fonction d'un biais electrique entre les couches externes. Nous trouvons une phase d'onde de densite de charge bidimensionnelle (ODC2D) comme etat fondamental du systeme. Cette ODC2D se nomme cristal dans ce memoire et nous derivons ses proprietes de transports et ses modes collectifs. Nous discutons egalement du caractere topologique de ce cristal. Notre etude englobe aussi les phases liquides avec ou sans coherence orbitale. Nous concluons notre memoire par l'etude de quelques signatures experimentales des phases du gaz d'electrons dans la tricouche.

  6. Nuclear biological studies in France; Les etudes de biologie nucleaires en France

    Coursaget, J. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires


    On the occasion of a colloquium on radiobiological research programmes, a number of documents dealing with French accomplishments and projects in this field were collected together. We felt that it would be useful to assemble these papers in one report; although they are brief and leave gaps to be filled in, they provide certain data, give an overall view of the situation, and can also suggest a rough plan for the general policy to adopt in the field of 'nuclear' biological research; i.e. research based on the nuclear tracer method or devoted to the action of ionising radiations. (author) [French] Un colloque sur les programmes de recherche en radiobiologie nous a donne l'occasion de reunir des documents sur les realisations et les projets francais dans ce domaine. Il nous a semble utile de reunir en un rapport l'ensemble de ces documents, qui, malgre leur brievete et malgre les lacunes qu'ils comportent, donnent un certain nombre d'informations, permettent une vue d'ensemble et peuvent dessiner aussi l'ebauche d'une politique coherente en matiere de recherches biologiques 'nucleaires', c'est-a-dire de recherches basees sur la methode des indicateurs nucleaires ou consacrees a l'action des rayonnements ionisants. (auteur)

  7. The SILENE reactor: an instrument suitable for studying the impact of intermediate and high radiation doses; Reacteur silene : outil adapte aux etudes appliquees a l'effet des moyennes et fortes doses

    Verray, B.; Leo, Y.; Fouillaud, P. [Commissariat a l' Energie Atomique, CEA, Service de Recherches en Neutronique et Criticite, SNRC, Valduc, Is sur Tille (France)


    Designed in 1974 to study the phenomenology and consequences of a criticality accident, the SILENE experimental reactor, an intense source of mixed neutron and gamma radiation, is also suited to radiobiological studies. (author)

  8. Preclinical Study for Application of Fabricated High Activity Ir-192

    Chun, Mi Son; Kang, Seung Hee; Oh, Young Taek; Jeong, Chul; Kim, Mi Hwa; Hwang, Jeong Hye; Kim, Hee Seong; Im, Eun Jeong [Ajou University, Suwon (Korea, Republic of)


    This study was performed to evaluate the feasibility and safety of high activity Ir-192 sources manufactured by KAERI(Korea Atomic Energy Research Institute) for application to present equipment such as various applicators inserted to patients and PLATO(Nucletron, Netherland) of treatment planning system and to evaluate safety and accuracy of Ir-192 as practical clinic use through in vitro dosimetry of Ir-192. We confirmed the physical and radiobiological safety of KAERI sources to use practical. KAERI sources are applicable to commercial high dose rate brachytherapy machine safely. Then those can be substituted for the imported sources such as sources made by Nucletron, Gammamed and exported to the foreign country

  9. Le transfert de connaissances entre les mathematiques et les sciences. Une etude exploratoire aupres d'eleves de 4e secondaire

    Samson, Ghislain


    'analyse qualitative et adaptee de la litterature (Thouin, 1995). Une seconde serie d'analyses permettant de categoriser les reponses selon la typologie des connaissances declaratives, procedurales et conditionnelles complete la prise de donnees. Nos resultats indiquent que les sujets sont tres influences par des elements de surface, principalement lorsqu'il s'agit de problemes auxquels ils ne sont pas habitues. En l'absence de connaissances de base, plusieurs sujets vont tendre vers des propositions de solution "pratico-pratique" provenant de leur vecu: cela nous apparait d'importance d'un point de vue didactique et en matiere de transfert. Lors des entretiens realises un mois plus tard, les sujets ont eprouve de la difficulte a se rappeler le contenu de l'epreuve. Et lorsqu'il y avait un rappel, celui-ci etait superficiel et surtout axe sur le contenu ou le contexte d'un probleme. La plupart des sujets ne pouvait nommer que deux ou trois elements (des problemes en mathematiques, en sciences physiques, le probleme de la fenetre, le probleme du laser, etc.). Nos resultats confirment ce que plusieurs chercheurs (Julo, 1995, Jonnaert et Vander Borght, 1999; Richard et al., 1990) qui s'interessent aux questions de l'apprentissage admettent aujourd'hui: l'eleve ne travaille jamais sur la situation proposee par l'enseignant, mais bien sur la representation qu'il s'en est construite. Au plan methodologique, cette recherche est interessante par la variete des sources de collecte de donnees utilisees, par l'application d'outils methodologiques et d'analyses originaux tires de la recherche et de la pratique. Du cote theorique, il resulte de cette etude une meilleure comprehension du processus de transfert des connaissances mathematiques vers les sciences physiques. Finalement, aux plans didactique et pedagogique, cette recherche alimente la reflexion sur l'apprentissage et l'enseignement des sciences au secondaire. Elle fait ressortir que les mathematiques sont importantes dans la mobilisation

  10. Professor Hassan K. Awwad; The Father of Radiation Oncology and Radiobiology in Egypt and the Arab World, His Good Deeds Last Forever and Inspire us for the Future.

    Zaghloul, Mohamed S; El-Badawi, Samy A; Abd Elbaky, Hoda


    Our most respected professor Hassan K. Awwad passed away on January 5th, 2007, at the age of 81. He was considered as the father of radiotherapy in Egypt. He was always named "The Professor", as he was the founder of the radiotherapy departments at the National Cancer Institute, Cairo University&Faculty of Medicine, Alexandria University. He also shared in developing NEMROCK (Kasr El Aini Center of Radiation Oncology and Nuclear Medicine), the place where he graduated and worked during his early years of experience. He, together with professor Reda Hamza, dean of NCI, Cairo at that time, had initiated 7 oncology centers all over Egypt, from Aswan in the South to Dammietta and Damanhour in the North. These 7 centers were developed by the Ministry of Health. Prof. Awwad and Prof. Hamza were responsible for facility providing and plans. They chose all the necessary equipment, tools and personnel. These centers were in action since 1988 and are currently taking care of the oncology patients in a wide area of the country. Prof. Awwad graduated from the Faculty of medicine, Cairo University, in 1949. He had his Medical Doctorate (MD) in Radiotherapy from Alexandria University in 1956. The International Atomic Energy Agency (IAEA) awarded him fellowships in France (Institute Gustave Rossy) to gain experience in brachytherapy in 1956 and 1971, England 1956, 1959. Another fellowship was awarded to Prof Awwad in Harvard University (Peter Bent Brigham Hospital) in radiobiology and radiotherapy during the years 1964-1965. He personally and with other members of the National Cancer Institute gave much of their efforts and time to teach, train and guide young radiotherapists, biologists, physicists and radiation therapists through direct on-hand teaching and training as well as holding training courses for radiation oncologists, physicists and technologists. He insisted to ensure its regularity 4 times yearly. These courses trained a lot of personnel from all over Egypt, Sudan

  11. Monte Carlo simulations for thermodynamical properties calculations of plasmas at thermodynamical equilibrium. Applications to opacity and equation of state calculations; Apport d'un code de simulation Monte Carlo pour l'etude des proprietes thermodynamiques d'un plasma a l'equilibre et application au calcul de l'elargissement des profils de raies ioniques emises dans les plasmas denses, aux opacites spectrales et aux equations d'etat de systemes fluides

    Gilles, D


    This report is devoted to illustrate the power of a Monte Carlo (MC) simulation code to study the thermodynamical properties of a plasma, composed of classical point particles at thermodynamical equilibrium. Such simulations can help us to manage successfully the challenge of taking into account 'exactly' all classical correlations between particles due to density effects, unlike analytical or semi-analytical approaches, often restricted to low dense plasmas. MC simulations results allow to cover, for laser or astrophysical applications, a wide range of thermodynamical conditions from more dense (and correlated) to less dense ones (where potentials are long ranged type). Therefore Yukawa potentials, with a Thomas-Fermi temperature- and density-dependent screening length, are used to describe the effective ion-ion potentials. In this report we present two MC codes ('PDE' and 'PUCE') and applications performed with these codes in different fields (spectroscopy, opacity, equation of state). Some examples of them are discussed and illustrated at the end of the report. (author)

  12. Contribution to the study of french pitchblendes; Contribution a l'etude des pechblendes francaises

    Geffroy, J. [Commissariat a l' Energie Atomique, Lab. de Mineralogie, Centre de Chatillon (France). Centre d' Etudes Nucleaires; Sarcia, J.A. [Commissariat a l' Energie Atomique, Div. de la Crouzille, Haute Vienne (France). Centre d' Etudes Nucleaires


    The authors first review the characteristics of uraninite-pitchblende, as deduced of present literature. They set apart from typical pitchblende a black oxide aspect, which probably corresponds to neo-formations, and a 'para-pitchblende' aspect, which they relate to deep sur-oxidation of normal pitchblende. They insist on the easy replacement of pitchblende by silica. and give indications as to changes in vein stones (fluorite, quartz, etc...). A detailed study of paragenesis and successions in french uranium districts follows (including discussion of uranium of uranium-bearing coals). The authors attempt to classify french pitchblende veins. They are chiefly epithermal and poor in satellite ores. Three types of deposits are identified: massive - pitchblende type, silica type, fluorite type. These deposits, as those of Portugal, are included in granite, Central-European peri-batholitic types where uranium associates which Ni, Co, Bi and Ag, are in France both rare and poor. Finally, the authors attempt to bring out in the european Hercynian area a particular distribution of paragenetic types. (authors) [French] Les auteurs recapitulent d'abord les caracteres et les occurences de l'uraninite - pechblende, tels qu'ils peuvent etre degages de l'actuelle bibliographie. Ils exposent ensuite les faits qui du point de vue mineralogique seulement ressortent de l'etude mineralogique et chalcographique des pechblendes francaises et de leurs satellites. Ils distinguent de la pechblende-type un facies oxyde noir; correspondant probablement a une neoformation, et un facies parapechblende, qui est rapporte a une sur oxydation hypogene de la pechblende proprement dite. Ils insistent sur le facile remaniement de la pechblende par la slice; et donnent quelques precisions sur les modifications des gangues (fluorine, quartz, etc...). Suit l'etude detaillee des parageneses et des successions dans les districts uraniferes francais: Divisions du

  13. Radioembolization of hepatocarcinoma with {sup 90}Y glass microspheres: development of an individualized treatment planning strategy based on dosimetry and radiobiology

    Chiesa, C.; Maccauro, M.; Aliberti, G.; Padovano, B.; Seregni, E.; Crippa, F. [Foundation IRCCS Istituto Nazionale Tumori, Nuclear Medicine Division, Milan (Italy); Mira, M.; Negri, A. [University of Milan, Postgraduate Health Physics School, Milan (Italy); Spreafico, C.; Morosi, C.; Civelli, E.; Lanocita, R.; Marchiano, A. [Foundation IRCCS Istituto Nazionale Tumori, Radiology 2, Milan (Italy); Romito, R.; Sposito, C.; Bhoori, S.; Facciorusso, A.; Mazzaferro, V. [Foundation IRCCS Istituto Nazionale Tumori, Surgery 1, Milan (Italy); Camerini, T. [Foundation IRCCS Istituto Nazionale Tumori, Scientific Direction, Milan (Italy); Carrara, M. [Foundation IRCCS Istituto Nazionale Tumori, Health Physics, Milan (Italy); Pellizzari, S. [University La Sapienza, Engineering Faculty, Rome (Italy); Migliorisi, M. [Foundation IRCCS Istituto Nazionale Tumori, Nuclear Medicine Division, Milan (Italy); Foundation IRCCS Istituto Nazionale Tumori, Clinical Engineering, Milan (Italy); De Nile, M.C. [University of Pavia, Physics Faculty, Pavia, Lombardy (Italy)


    The aim of this study was to optimize the dosimetric approach and to review the absorbed doses delivered, taking into account radiobiology, in order to identify the optimal methodology for an individualized treatment planning strategy based on {sup 99m}Tc-macroaggregated albumin (MAA) single photon emission computed tomography (SPECT) images. We performed retrospective dosimetry of the standard TheraSphere registered treatment on 52 intermediate (n = 17) and advanced (i.e. portal vein thrombosis, n = 35) hepatocarcinoma patients with tumour burden < 50 % and without obstruction of the main portal vein trunk. Response was monitored with the densitometric radiological criterion (European Association for the Study of the Liver) and treatment-related liver decompensation was defined ad hoc with a time cut-off of 6 months. Adverse events clearly attributable to disease progression or other causes were not attributed to treatment. Voxel dosimetry was performed with the local deposition method on {sup 99m}Tc-MAA SPECT images. The reconstruction protocol was optimized. Concordance of {sup 99m}Tc-MAA and {sup 90}Y bremsstrahlung microsphere biodistributions was studied in 35 sequential patients. Two segmentation methods were used, based on SPECT alone (home-made code) or on coregistered SPECT/CT images (IMALYTICS trademark by Philips). STRATOS trademark absorbed dose calculation was validated for {sup 90}Y with a single time point. Radiobiology was used introducing other dosimetric variables besides the mean absorbed dose D: equivalent uniform dose (EUD), biologically effective dose averaged over voxel values (BED{sub ave}) and equivalent uniform biologically effective dose (EUBED). Two sets of radiobiological parameters, the first derived from microsphere irradiation and the second from external beam radiotherapy (EBRT), were used. A total of 16 possible methodologies were compared. Tumour control probability (TCP) and normal tissue complication probability (NTCP) were

  14. Etude de la dynamique des porteurs dans des nanofils de silicium par spectroscopie terahertz

    Beaudoin, Alexandre

    Ce memoire presente une etude des proprietes de conduction electrique et de la dynamique temporelle des porteurs de charges dans des nanofils de silicium sondes par rayonnement terahertz. Les cas de nanofils de silicium non intentionnellement dopes et dopes type n sont compares pour differentes configurations du montage experimental. Les mesures de spectroscopie terahertz en transmission montre qu'il est possible de detecter la presence de dopants dans les nanofils via leur absorption du rayonnement terahertz (˜ 1--12 meV). Les difficultes de modelisation de la transmission d'une impulsion electromagnetique dans un systeme de nanofils sont egalement discutees. La detection differentielle, une modification au systeme de spectroscopie terahertz, est testee et ses performances sont comparees au montage de caracterisation standard. Les instructions et des recommendations pour la mise en place de ce type de mesure sont incluses. Les resultats d'une experience de pompe optique-sonde terahertz sont egalement presentes. Dans cette experience, les porteurs de charge temporairement crees suite a l'absorption de la pompe optique (lambda ˜ 800 nm) dans les nanofils (les photoporteurs) s'ajoutent aux porteurs initialement presents et augmentent done l'absorption du rayonnement terahertz. Premierement, l'anisotropie de l'absorption terahertz et de la pompe optique par les nanofils est demontree. Deuxiemement, le temps de recombinaison des photoporteurs est etudie en fonction du nombre de photoporteurs injectes. Une hypothese expliquant les comportements observes pour les nanofils non-dopes et dopes-n est presentee. Troisiemement, la photoconductivite est extraite pour les nanofils non-dopes et dopes-n sur une plage de 0.5 a 2 THz. Un lissage sur la photoconductivite permet d'estimer le nombre de dopants dans les nanofils dopes-n. Mots-cles: nanofil, silicium, terahertz, conductivite, spectroscopie, photoconductivite.

  15. Etude theorique et experimentale des evaporateurs de dioxyde de carbone operant dans des conditions de givrage

    Bendaoud, Adlane Larbi

    Les evaporateurs de refrigeration sont surtout du type tube a ailettes, appeles serpentins, et fonctionnent dans l'une des conditions suivantes: seche, humide ou avec formation de givre. Il a ete demontre que la formation du givre sur la paroi exterieure de l'echangeur engendre une surconsommation energetique a cause des operations de degivrage puisque 15 a 20% seulement de la chaleur produite sert au degivrage tandis que le reste est dissipee dans l'environnement [1]. Avec l'avenement des nouveaux refrigerants, moins nocifs envers l'environnement, l'industrie du froid se trouve penalisee du fait que peu ou pas de composantes mecaniques (compresseur, pompe, echangeur...etc.) adaptees sont disponibles [3]. Il s'agit pour la communaute des frigoristes de combler ce retard technologique en redeveloppant ces composantes mecaniques afin qu'elles soient adaptees aux nouveaux refrigerants. Dans cette optique, et afin de mieux comprendre le comportement thermique des evaporateurs au CO2 fonctionnant dans des conditions seches, qu'un groupe de chercheurs du CanmetENERGIE avaient lance, en 2000, un programme de R & D. Dans le cadre de programme un outil de simulation des evaporateurs au CO2 a ete developpe et un banc d'essai contenant une boucle secondaire de refrigeration utilisant le CO2 comme refrigerant a ete construit. Comme continuite de ce travail de recherche, en 2006 ce meme groupe de recherche a lance un nouveau projet qui consiste a faire une etude theorique et experimentale des evaporateurs au CO2 operants dans des conditions de givrage. Et, c'est exactement dans le cadre de ce projet que se positionne ce travail de these. Ce travail de recherche a ete entrepris pour mieux comprendre le comportement thermique et hydrodynamique des serpentins fonctionnant dans des conditions de givrage, l'effet des circuits de refrigerant ainsi que celui des parametres geometriques et d'operation. Pour cela, un travail theorique supporte par une etude experimentale a ete effectue

  16. SU-C-BRE-05: PTV Margin Determination Based On Tumor Radiobiological Characteristics and Geometric Uncertainties Derived From Daily Cone- Beam CT Images

    Selvaraj, J [Inlaks and Budhrani Hospital (India)


    Purpose: To determine required PTV margins for ≤1% loss in mean population TCP using systematic (Σ) and random (σ) errors calculated from daily cone-beam CT (CBCT) images of head and neck patients. Methods: Daily CBCT images were acquired for 50 head and neck patients. The CBCT image sets acquired at each fraction were registered with planning CT to obtain positional errors for each patient for each fraction. Systematic and random errors were calculated from data collected for 50 patients as described in IPEM On Target report. CTV delineation uncertainty of 2mm is added quadratically to systematic error. Assuming a spherical target volume, the dose in each voxel of target volume is summed for each fraction in the treatment by shifting the dose grid to calculate mean population TCP inclusive of geometric uncertainties using a Monte Carlo method. These simulations were repeated for the set of Σ and σ in each axis for different PTV margins and drop in TCP for each margin are obtained. In order to study the effect of dose-response curve on PTV margins, two different σα of 0.048 Gy-1 and 0.218 Gy-1 representing steep and shallow dose-response curves are studied. Σ were 2.5, 2.5, 2.1 mm and σ were 0.3, 0.3 0.2 mm respectively in x, y and z axis respectively. Results: PTV margins based on tumor radiobiological characteristics are 4.8, 4.8 and 4 mm in x, y and z axis assuming 25 treatment fractions for σα 0.048 Gy-1 (steep) and 4.2,4.2 and 2.2 for σα of 0.218 Gy-1 (shallow). While the TCP-based margins did not differ much in x and y axis, it is considerably smaller in z axis for shallow DRC. Conclusion: TCP based margins are substantially smaller than physical dose-based margin recipes. This study also demonstrates the importance of considering tumor radiobiological characteristics while deriving margins.

  17. Comparison of Different Fractionation Schedules Toward a Single Fraction in High-Dose-Rate Brachytherapy as Monotherapy for Low-Risk Prostate Cancer Using 3-Dimensional Radiobiological Models

    Mavroidis, Panayiotis, E-mail: [Department of Radiation Oncology, University of Texas Health Sciences Center, San Antonio, Texas (United States); Department of Medical Radiation Physics, Karolinska Institutet and Stockholm University, Stockholm (Sweden); Milickovic, Natasa [Department of Medical Physics and Engineering, Strahlenklinik, Klinikum Offenbach GmbH, Offenbach (Germany); Cruz, Wilbert F. [Department of Radiation Oncology, University of Texas Health Sciences Center, San Antonio, Texas (United States); Tselis, Nikolaos [Strahlenklinik, Klinikum Offenbach GmbH, Offenbach (Germany); Karabis, Andreas [Pi-Medical Ltd., Athens (Greece); Stathakis, Sotirios; Papanikolaou, Nikos [Department of Radiation Oncology, University of Texas Health Sciences Center, San Antonio, Texas (United States); Zamboglou, Nikolaos [Strahlenklinik, Klinikum Offenbach GmbH, Offenbach (Germany); Baltas, Dimos [Department of Medical Physics and Engineering, Strahlenklinik, Klinikum Offenbach GmbH, Offenbach (Germany); Nuclear and Particle Physics Section, Physics Department, University of Athens, Athens (Greece)


    Purpose: The aim of the present study was the investigation of different fractionation schemes to estimate their clinical impact. For this purpose, widely applied radiobiological models and dosimetric measures were used to associate their results with clinical findings. Methods and Materials: The dose distributions of 12 clinical high-dose-rate brachytherapy implants for prostate were evaluated in relation to different fractionation schemes. The fractionation schemes compared were: (1) 1 fraction of 20 Gy; (2) 2 fractions of 14 Gy; (3) 3 fractions of 11 Gy; and (4) 4 fractions of 9.5 Gy. The clinical effectiveness of the different fractionation schemes was estimated through the complication-free tumor control probability (P{sub +}), the biologically effective uniform dose, and the generalized equivalent uniform dose index. Results: For the different fractionation schemes, the tumor control probabilities were 98.5% in 1 × 20 Gy, 98.6% in 2 × 14 Gy, 97.5% in 3 × 11 Gy, and 97.8% in 4 × 9.5 Gy. The corresponding P{sub +} values were 88.8% in 1 × 20 Gy, 83.9% in 2 × 14 Gy, 86.0% in 3 × 11 Gy, and 82.3% in 4 × 9.5 Gy. With use of the fractionation scheme 4 × 9.5 Gy as reference, the isoeffective schemes regarding tumor control for 1, 2, and 3 fractions were 1 × 19.68 Gy, 2 × 13.75 Gy, and 3 × 11.05 Gy. The optimum fractionation schemes for 1, 2, 3, and 4 fractions were 1 × 19.16 Gy with a P{sub +} of 91.8%, 2 × 13.2 Gy with a P{sub +} of 89.6%, 3 × 10.6 Gy with a P{sub +} of 88.4%, and 4 × 9.02 Gy with a P{sub +} of 86.9%. Conclusions: Among the fractionation schemes 1 × 20 Gy, 2 × 14 Gy, 3 × 11 Gy, and 4 × 9.5 Gy, the first scheme was more effective in terms of P{sub +}. After performance of a radiobiological optimization, it was shown that a single fraction of 19.2 to 19.7 Gy (average 19.5 Gy) should produce at least the same benefit as that given by the 4 × 9.5 Gy scheme, and it should reduce the expected total complication probability by

  18. Stable isotope separation; Separations physicochimiques d'isotopes stables realisations et etudes de petites productions

    Botter, F.; Molinari, Ph.; Dirian, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    type, de capacite totale environ 2 litres, il a ete realise un appareil preparatif, de faible volume mort, permettant de produire 1 litre de D{sub 2} pur a partir des melange 50 p.100 D{sub 2}, 50 p.100 H{sub 2} en 12 minutes environ. Sur le plan theorique, en premiere approximation, nous assimilions la chromatographie a un fractionnement contre courant en negligeant resistance superficielle a l'echange ainsi que diffusions longitudinale et laterale. On etablit graphiquement ou par calcul, le nombre de plateaux theoriques necessires a un certain enrichissement de la phase gazeuse ce qui permet de comparer l'efficacite de colonnes qui different par leur masse palladiee. DIFFUSION THERMIQUE: Afin d'assurer une separation des isotopes de l'hydrogene, on a realise une installation de diffusion thermique construite en acier inoxydable et entierement telecommandee. La cascade de separation se compose de deux couples identiques de colonnes a fil central chaud. Chaque couple peut travailler isolement ou etre relie par thermosyphon. La temperature du fil chaud est de l'ordre de 1000 deg C entretenue par courant redresse. Avec cette installation, des echantillons d'hydrogene a la teneur isotopique en deuterium inferieure a 0,5 ppm. ont ete obtenus a partir d'un gaz initial a 32 ppm. Il a ainsi ete possible de preparer du tritium a la teneur de 99,3 p. 100 a partir d'un gaz d'une teneur initale de 6 p. 100. Pour la separation quantitative du Xenon enrichi cinq fois en {sup 124}Xe par thermodiffusion on a construit deux cascades identiques de 5 colonnes fonctionnant en parallele, reliees par thermosyphon ou par tube capillaire lie a un oscillateur thermique de gaz. Le fil central en tungstene fonctionne a 1200 deg C. Les colonnes sont groupees a la facon d'un faisceau tubulaire d'un echangeur de chaleur dans une virole de 30 cm de diametre ou circule l'eau de refroidissement. Des etudes sont en cours pour augmenter le

  19. Study of the fluctuations of the partial and total radiative widths by neutron capture resonance method; Etude des fluctuations des largeurs radiatives partielles et totales par la capture des neutrons de resonance

    Huynh, V.D. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    Radiative capture experiments by neutron time-of-flight methods have been made for following studies: distribution of partial radiative widths, effects of correlation between different radiative transitions, fluctuations of total radiative widths {gamma}{sub {gamma}} from resonance to resonance, variation of {gamma}{sub {gamma}} with number of mass and the search for the existence of potential capture. Also, some other experiments with the use of neutron capture gamma-rays spectra have been investigated. (author) [French] Par la capture des neutrons de resonance dont les energies sont selectionnees a l'aide de la technique du temps de vol, differents types d'experiences ont ete realisees concernant les etudes des distributions des largeurs radiatives partielles, des effets de correlation entre differentes voies de desexcitation, de la fluctuation des largeurs radiatives totales {gamma}{sub {gamma}} de resonance a resonance, de la variation de la quantite {gamma}{sub {gamma}} en fonction du nombre de masse et de la mise en evidence de l'existence du processus de capture potentielle. Quelques autres applications de l'emploi du spectre de rayons gamma ont egalement ete presentees. (auteur)

  20. Optical spectroscopy of Cm{sup 3+} in the elpasolite Cs{sub 2} NaYCl{sub 6}. Application in the structural study of Cm(III) sorption on phosphate materials; Spectroscopie optique de Cm{sup 3+} dans l`elpasolite Cs{sub 2}NaYCl{sub 6}. Application a l`etude structurale de la sorption de Cm(III) sur des materiaux phosphates

    Cavellec, Ronan [Universite de Paris Sud, 91 - Orsay (France)


    Radwaste management involves important research. In order to contribute to this program we proposed the examination of two different and complementary aspects of nuclear waste: the detection by laser spectroscopy of trivalent actinide ions diluted in a crystal host and the migration of radionuclides through different barriers in geosphere that is related to understanding and modelling the sorption processes. In both cases the spectro-fluorimetry laser is used to investigate different phenomenological processes at microscopic scale. The first part of the thesis deals with the investigation of Cm{sup 3+} energy levels in Cs{sub 2}NaYCl{sub 6}. From the analysis of excitation and emission spectra 52 crystal-field levels have been assigned and the phenomenological parameters calculated. A discussion about these parameters, compared with those in case of LaCl{sub 3} and ThO{sub 2} cases, is given. An intense green fluorescence has been found for the first time for Cm{sup 3+} in elpasolite. Thus, this material seems to be a promising solid for the analytical application of actinides such as Cm{sup 3+} and Am{sup 3+} ions. In the second part the sorption of curium (5{center_dot}10{sup -8} mol {center_dot}l{sup -1}) onto phosphate materials was studied. The ionic strength, electrolyte nature and complexing agent were investigated. The laser spectro-fluorimetry is shown to be a powerful technique. The formation of surface complexes for ZrP{sub 2}O{sub 7}, Zr{sub 2}O(PO{sub 4}){sub 2} and Th{sub 4}(PO{sub 4}){sub 4}P{sub 2}O{sub 7} has been demonstrated. Fluorescence lifetime measurements indicate that in complexing medium the aqueous complex of Cm is sorbed preferentially to the Cm{sup 3+} free ion onto the solid 82 refs., 54 figs., 35 tabs.

  1. The development of a very high stability electrostatic generator (1962); Etude et realisation d'un generateur electrostatique a tres haute stabilite (1962)

    Jonckheere, R.E.L. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires


    This thesis deals with the study of an electrostatic high voltage generator having a voltage stability of the order of 10{sup -6} per minute. This equipment should be very useful in electron microscopy. The electrostatic generator is studied as a control system element: transfer function, parasitic signals and noise are determined and a mathematical model is proposed. A theoretical study of the open loop transfer function, stability, transient response, voltage stabilization of five different control systems shows which one should be able to fulfill the requirements There follows a detailed study of drift, a description of the actual system and performance data. (author) [French] Cette etude concerne un generateur electrostatique capable de fournir une tres haute tension continue dont la stabilite relative est de l'ordre de 10{sup -6} pendant une minute. Une telle performance rend cet appareillage tres utile en microscopie electronique. La generatrice electrostatique est etudiee en tant qu'element d'un systeme asservi: on determine successivement la fonction de transfert, les perturbations, le bruit de fond et le modele mathematique. L'etude de cinq differents circuits de regulation en ce qui concerne leur fonction de transfert, stabilite, reponse en regime transitoire, attenuation des perturbations, permettra de choisir le systeme qui semble le mieux repondre aux exigences. Viennent ensuite une etude detaillee de la derive, la description de la realisation pratique et les resultats de mesure. (auteur)

  2. Study of the solubility of plutonyl nitrate with a view to its extraction by a solvent; Etude de la solubilite du nitrate de plutonyle en vue de son extraction par solvant

    Vergnaud, G. [Commissariat a l' Energie Atomique, Fontenay aux Roses (France). Centre d' Etudes Nucleaires


    The research covers the determination of the partition coefficient of plutonyl nitrate and their application to the industrial treatment of plutonium. The solvent used is a tri-n-butyl phosphate solution diluted to 30 per cent in dodecane. The parameters which have been studied and which can affect the extraction of the plutonyl nitrate are: the plutonyl nitrate concentration; the nitric acid concentration; the uranyl nitrate concentration; the tetravalent plutonium nitrate concentration. The industrial application has been studied using a battery of mixer-separators. The operational conditions are defined in the case of a conventional plutonium separation plant. The results obtained, for a higher plutonyl nitrate concentration than that actually planned, are satisfactory and encouraging as far as the operation is concerned. Only the presence of polymerized tetravalent plutonium can adversely affect the satisfactory extraction of the plutonium. (author) [French] L'etude porte sur les coefficients de partage du nitrate de plutonyle et leur application a l'elaboration industrielle du plutonium. Le solvant utilise est une solution de phosphate de tri-n-butyle, dilue a 30 pour cent dans le dodecane. Les parametres etudies et pouvant influencer l'extraction du nitrate de plutonyle, par ce solvant, sont: concentration du nitrate de plutonyle; concentration de l'acide nitrique; concentration du nitrate d'uranyle; concentration au nitrate de plutonium tetravalent. L'application industrielle est etudiee au moyen d'une batterie de melangeurs-decanteurs. Les conditions operatoires sont definies d'apres un schema classique d'usine de separation de plutonium. Les resultats obtenus, pour une concentration du nitrate de plutonyle superieure a celle reellement prevue, sont satisfaisants et encourageants pour l'exploitation. Seule, la presence de plutonium tetraralent polymerise, peut nuire a une bonne extraction du plutonium

  3. Development of a single ion micro-irradiation facility for experimental radiobiology at cell level; Developpement d'une ligne d'irradiation microfaisceau en mode ion par ion pour la radiobiologie experimentale a l'echelle cellulaire

    Barberet, Ph


    A micro-irradiation device has been developed for radiobiology applications at the scale of the cell. This device is based on an upgrade of an existing micro-beam line that was already able to deliver a 1 to 3 MeV proton or alpha beam of low intensity and whose space resolution is lower than 1 micrometer in vacuum. The important part of this work has been the development of an irradiation stage designed to fit on the micro-probe and able to deliver ions in the air with an absolute accuracy of a few micrometers. A program has been set up to monitor the complete irradiation line in testing and in automatic irradiation operating phases. Simulation tools based on Monte-Carlo calculations have been validated through comparisons with experimental data particularly in the field of spatial resolution and of the number of ions delivered. The promising results show the possibility in a near future to use this tool to study the response of cells to very low irradiation doses down to the extreme limit of one ion per cell.

  4. Comparison of cytogenetic effects in bone marrow of mice after the flight on the biosatellite "BION-M1" and the ground-based radiobiological experiment

    Dorozhkina, Olga; Vorozhtsova, Svetlana; Ivanov, Alexander


    During space flight, the astronauts are exposed to radiation exposure at low doses with low dose rates, so one of the actual areas of Radiobiology is research of action of ionizing radiation in low and ultra-low doses. Violation of the chromosome apparatus of living biosystems, ranging from viruses and bacteria to humans, is the most reliable evidence of exposure to ionizing radiation. In this regard, the study of cytogenetic damage in the cells of humans and animals is central to space radiobiology (Fedorenko B.S., 2006). In experiment "BION - M1" by anaphase method was determined level of chromosomal aberrations in bone marrow cells of tibia of mice. Flight duration biosatellite "BION - M1" (Sychev V.N. et al., 2014) was 30 days in Earth orbit. Euthanasia of experimental animals was carried out after 12 hours from the moment of landing satellite by method of cervical dislocation. The level of chromosomal aberrations in vivarium-housed control mice was 1,75 ± 0,6% and 1,8 ± 0,45%, while the mitotic index 1,46 ± 0,09% and 1,53 ± 0,05%. The content of animals in the experiment with onboard equipment led to some increase in aberrant mitosis (2,3 ± 0,4%) and reduction of the mitotic index (1,37 ± 0,02%). In the flight experiment "BION-M1" was a statistically significant increase in level of chromosome aberrations (29,7 ± 4,18%) and a decrease in the mitotic index (0,74 ± 0,07%). According to VA Shurshakova (2014), the radiation dose to mice ranged from 32 to 72 mGy and relate to a range of small doses (ICRP, 2012). In this connection we conducted a series of experiments in the ground conditions, the aim of which was the study of earliest effects of ionizing radiation in vivo in mice irradiated with low doses of γ-irradiation of 10 to 200 mGy in the first 24 hours after exposure, i.e. within the first post-radiation exposure cell cycle. Studies were carried out on adult female mice outbred ICR (CD-1) - SPF category at the age of 4-4.5 months with an average

  5. The in vivo study on the radiobiologic effect of prolonged delivery time to tumor control in C57BL mice implanted with Lewis lung cancer

    Zhu Guo-Pei


    Full Text Available Abstract Background High-precision radiation therapy techniques such as IMRT or sterotactic radiosurgery, delivers more complex treatment fields than conventional techniques. The increased complexity causes longer dose delivery times for each fraction. The purpose of this work is to explore the radiobiologic effect of prolonged fraction delivery time on tumor response and survival in vivo. Methods 1-cm-diameter Lewis lung cancer tumors growing in the legs of C57BL mice were used. To evaluate effect of dose delivery prolongation, 18 Gy was divided into different subfractions. 48 mice were randomized into 6 groups: the normal control group, the single fraction with 18 Gy group, the two subfractions with 30 min interval group, the seven subfractions with 5 min interval group, the two subfractions with 60 min interval group and the seven subfractions with 10 min interval group. The tumor growth tendency, the tumor growth delay and the mice survival time were analyzed. Results The tumor growth delay of groups with prolonged delivery time was shorter than the group with single fraction of 18 Gy (P 0.05. Compared to the group with single fraction of 18 Gy, the groups with prolonged delivery time shorten the mice survival time while there was no significant difference between the groups with prolonged delivery time 30 min and the groups with prolonged delivery time 60 min. Conclusions The prolonged delivery time with same radiation dose shorten the tumor growth delay and survival time in the mice implanted with Lewis lung cancer. The anti-tumor effect decreased with elongation of the total interfractional time.

  6. The in vivo study on the radiobiologic effect of prolonged delivery time to tumor control in C57BL mice implanted with Lewis lung cancer.

    Wang, Xin; Xiong, Xiao-Peng; Lu, Jiade; Zhu, Guo-Pei; He, Shao-Qin; Hu, Chao-Su; Ying, Hong-Mei


    High-precision radiation therapy techniques such as IMRT or sterotactic radiosurgery, delivers more complex treatment fields than conventional techniques. The increased complexity causes longer dose delivery times for each fraction. The purpose of this work is to explore the radiobiologic effect of prolonged fraction delivery time on tumor response and survival in vivo. 1-cm-diameter Lewis lung cancer tumors growing in the legs of C57BL mice were used. To evaluate effect of dose delivery prolongation, 18 Gy was divided into different subfractions. 48 mice were randomized into 6 groups: the normal control group, the single fraction with 18 Gy group, the two subfractions with 30 min interval group, the seven subfractions with 5 min interval group, the two subfractions with 60 min interval group and the seven subfractions with 10 min interval group. The tumor growth tendency, the tumor growth delay and the mice survival time were analyzed. The tumor growth delay of groups with prolonged delivery time was shorter than the group with single fraction of 18 Gy (P delivery time 30 min was longer than that of groups with prolonged delivery time 60 min P delivery time (P > 0.05). Compared to the group with single fraction of 18 Gy, the groups with prolonged delivery time shorten the mice survival time while there was no significant difference between the groups with prolonged delivery time 30 min and the groups with prolonged delivery time 60 min. The prolonged delivery time with same radiation dose shorten the tumor growth delay and survival time in the mice implanted with Lewis lung cancer. The anti-tumor effect decreased with elongation of the total interfractional time.

  7. SU-E-T-375: Passive Scattering to Pencil-Beam-Scanning Comparison for Medulloblastoma Proton Therapy: LET Distributions and Radiobiological Implications

    Giantsoudi, D; MacDonald, S; Paganetti, H [Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States)


    Purpose: To compare the linear energy transfer (LET) distributions between passive scattering and pencil beam scanning proton radiation therapy techniques for medulloblastoma patients and study the potential radiobiological implications. Methods: A group of medulloblastoma patients, previously treated with passive scattering (PS) proton craniospinal irradiation followed by prosterior fossa or involved field boost, were selected from the patient database of our institution. Using the beam geometry and planning computed tomography (CT) image sets of the original treatment plans, pencil beam scanning (PBS) treatment plans were generated for the cranial treatment for each patient, with average beam spot size of 8mm (sigma in air at isocenter). 3-dimensional dose and LET distributions were calculated by Monte Carlo methods (TOPAS) both for the original passive scattering and new pencil beam scanning treatment plans. LET volume histograms were calculated for the target and OARs and compared for the two delivery methods. Variable RBE weighted dose distributions and volume histograms were also calculated using a variable dose and LET-based model. Results: Better dose conformity was achieved with PBS planning compared to PS, leading to increased dose coverage for the boost target area and decreased average dose to the structures adjacent to it and critical structures outside the whole brain treatment field. LET values for the target were lower for PBS plans. Elevated LET values for OARs close to the boosted target areas were noticed, due to end of range of proton beams falling inside these structures, resulting in higher RBE weighted dose for these structures compared to the clinical RBE value of 1.1. Conclusion: Transitioning from passive scattering to pencil beam scanning proton radiation treatment can be dosimetrically beneficial for medulloblastoma patients. LET–guided treatment planning could contribute to better decision making for these cases, especially for

  8. Contribution to the study of the biological properties of compounds labeled with radio-chromium {sup 51}Cr; Contribution a l'etude des proprietes biologiques des composes marques au radiochrome {sup 51}Cr

    Ingrand, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    Among the radioisotopes commonly used in biology and medicine which are controlled Individually in the Radioelement Departement of the Saclay Nuclear Research Centre before being sent to the users, the author has chosen chromium 51 incorporated in inorganic salts or in organic substrates for a study of the biological properties of the compounds. In the first part, he has compared the pathways followed by the radioactive sodium chromate and chromic chloride mixed with blood or given to the whole animal, the object being to determine whether a reduction of hexavalent chromium occurs, both in vitro and in vivo. In the second part, the author has tried to show the validity of using, various substrates labeled with chromium 51, red cells, haemoglobin, plasma proteins and cytochrome c. The results obtained have contributed to underline the interest of using such compounds for biological applications. (author) [French] Parmi les radioisotopes d'utilisation courants en biologie et en medecine qui sont l'objet d'un controle particulier dans le Departement des Radioelements du Centre d'Etudes Nucleaires de Saclay avant leur diffusion aux utilisateurs, l'auteur a choisi le chrome 51 incorpore a des sels mineraux ou a des substrats organiques, afin d'en etudier les proprietes biologiques. Dans la premiere partie, il a compare le sort du chromate de sodium et du chlorure chromique radioactifs melanges a du sang ou administres a l'animal entier en s'efforcant de mettre en evidence une reduction du chrome hexavalent aussi bien in vitro qu'in vivo. Dans la deuxieme partie, il a cherche a etablir la validite de l'emploi de differents substrats marques au chrome 51, l'hematie, l'hemoglobine, les proteines plasmatiques et le cytochrome c. Les resultats obtenus ont permis de souligner le reel interet des applications biologiques des composes marques par le radioisotope. (auteur)

  9. Contribution to the studies on the mineral content of plant material through radioactivation analysis; Contribution a l'etude de la composition minerale des matieres vegetales au moyen de l'analyse par radioactivation

    Fourcy, A. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires


    Radioactivation analysis is by its great sensibility or its rapidity quite helpful in plant biology and agronomy. Specific composition of plants and results to obtain in biological experimentation have needed a practical research on analytical methods for plant materials, using for radioactivation swimming-pool reactor neutrons and 14 MeV neutrons from a generator. Dosage process for 25 elements is exposed, taking account of the interest of the analysis for each element, the average amount occurring in plants and the result obtained. Many applications are developed, concerning nutrition physiology, genetics, parasitology, toxicology, control of manufactured agricultural and pharmaceutical products industrial and pesticides residues, ecology, radioecology and biochemistry. (author) [French] L'analyse par radioactivation, par sa grande sensibilite ou sa rapidite, est susceptible de rendre de nombreux services en biologie vegetale et en agronomie. La composition particuliere des plantes et les buts recherches dans l'experimentation ont exige une etude concrete des methodes d'analyse propres a la matiere vegetale en utilisant, pour la radioactivation, soit un reacteur de type piscine a eau legere, soit un accelerateur generateur de neutrons de 14 MeV. Le mode de dosage de 25 elements est expose en tenant compte de l'interet de l'analyse de chaque element, des teneurs moyennes rencontrees dans les plantes, et du resultat atteint. De nombreuses applications sont developpees qui touchent a la physiologie de la nutrition, la genetique, la parasitologie, la toxicologie, le controle des fabrications, les pollutions industrielles, l'ecologie, la radioecologie et la biochimie. (auteur)

  10. Study of the long-term values and prices of plutonium; a simplified parametrized model; Etude des valeurs et des prix du plutonium a long terme; un modele parametre simplifie

    Gaussens, J.; Paillot, H. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    The authors define the notions of use values and price of plutonium. They give a 'simplified parametrized model' simulating the equilibrium of the offer and the demand in time, concerning the plutonium and the price deriving from the relative scarcity of this metal, taking into account the technical and economic operating parameters of the various reactors confronted. This model is simple enough to allow direct computations and establish clear relations between the various parameters. The use of the linear programmes method allows on the other hand a wide extension of the model. This report includes three main parts: I - General description of the study (without detailed calculations) II - Mathematical development of the simplified parametrized model and application (the basic data and the results of the calculations are given) III - Appendices (giving the detailed computations of part II). (authors) [French] Les auteurs definissent les notions de valeurs d'usage et de prix du plutonium. Ils donnent un 'modele parametre simplifie' simulant l'equilibre de l'office et de la demande dans le temps concernant le plutonium et le prix qui decoule de la rarete relative de ce metal, compte tenu des parametres techniques et economiques de fonctionnement des divers reacteurs en presence. Ce modele est suffisamment simple pour permettre des calculs manuels et etablir des liaisons claires entre les divers parametres. L'utilisation de la technique des programmes lineaires permet par ailleurs une extension considerable du modele. Cette note comprend trois parties: I - Expose general de l'etude (sans expose du detail des calculs) II - Developpement mathematique du modele parametre simplifie et application (on precise les donnees de base et le resultat des calculs) III - Annexes (donnant le detail des calculs de la partie II). (auteurs)

  11. Etude par spectroscopie de Coulomb de points quantiques lateraux individuels et couples

    Pioro-Ladriere, Michel

    Des points quantiques contenant un nombre discret et variable d'electrons sont formes dans un gaz bi-dimensionnel d'electrons a l'aide de grilles metalliques. Le transport electrique, le blocage de spin et la detection de charge sont employes comme outils spectroscopiques permettant de sonder les proprietes de ces nanostructures. Ces techniques permettent aussi de controler exactement le nombres d'electrons confines dans des points quantiques individuels et couples en utilisant un patron de grille judicieux. Une technique de refroidissement en tension est developpee afin de minimiser les effets parasites du bruit telegraphique. Ce type de bruit de charge deteriore la stabilite des nanostructures laterales par l'activation d'un minuscule courant de fuite entre les grilles et le gaz bi-dimensionnel. Un modele expliquant le role du refroidissement en tension sur le courant de fuite est presente. L'activation du courant de fuite est confirmee par detection de charge. Les effets des interactions entre les electrons pieges dans un point quantique sont ensuite etudies dans un regime ou il est possible de comparer les resulats experimentaux avec ceux obtenus par diagonalisation exacte. L'etude demontre que la phase associee au facteur de remplissage nu = 2 est instable au-dessus d'un nombre critique d'electrons. Cette instabilite est confirmee experimentalement par blocage de spin. On demontre aussi l'existence d'etats correles dans le regime des renversements de spin, associe au passage de la phase nu = 2 a nu = 1. Les etats correles sont identifies par spectroscopie en transport non lineaire. Cette caracterisation du diagramme de phase de points individuels permet de coupler deux points quantiques configures a nu = 2. Pour ce regime, la nanostructure se comporte comme un systeme a deux niveaux pouvant contenir entre un et quatre electrons de valence et ce, meme si le nombre total d'electrons est plus eleve. Les degres de liberte de charge et de spin des deux points

  12. La structure de l'eau liquide: Une etude thermique par spectroscopie infrarouge

    Larouche, Pascal

    Le probleme de la structure de l'eau liquide est important car l'eau est le liquide le plus present sur Terre, et complexe, la quete d'un modele precis pour decrire comment fonctionne ce liquide ayant debute des la fin du dix-neuvieme siecle. Cette etude aborde ce probleme en etudiant l'effet de l'augmentation de la temperature sur H2O et D 2O purs a l'aide de la spectroscopie infrarouge. L'intervalle de temperatures scrute est 29--93.1°C. Les spectres enregistres sont des spectres MIR-ATR entre 650 et 6000 cm-1 . L'analyse par facteurs de ces donnees permet de montrer que deux et seulement deux facteurs principaux sont necessaires pour decomposer tous les spectres experimentaux. Ces resultats sont confirmes grace a l'analyse par facteurs de spectres de la region FIR. Par la suite, la transformation en spectres de la partie reelle n et imaginaire k de l'indice de refraction permet de combiner les donnees des regions MIR et FIR. Une fois ce calcul termine, les spectres de transmission complets de H 2O et D2O entre 25 et 90°C sont connus. Ils sont ensuite utilises pour calculer par extrapolation le spectre des especes constituant l'eau liquide, puis leur abondance en fonction de la temperature. L'extrapolation de ces abondances montre que les especes correspondent a des temperatures limites de --18 et 122°C. Par la suite, la decomposition gaussienne des spectres d'especes met en evidence la riche structure de ces objets et permet de demontrer que l'apparent deplacement du massif d'absorption OH (OD) est produit par une variation de l'intensite des bandes et non pas de leur deplacement. L'examen attentif des spectres des especes prouve qu'il n'y a pas de OH libres crees par l'augmentation de la temperature: meme a 93.1°C, chaque molecule possede quatre liens-H. Ces conclusions sont de plus confirmees par une analyse thermodynamique du passage des molecules de la phase solide a la phase gazeuse. Pour diversifier la nature des resultats experimentaux utilises, des

  13. Effect of nutritional intervention on the prevalence of metabolic syndrome and heart disease risk factors in urban Tehran /Effet d'une intervention nutritionnelle sur la prevalence du syndrome metabolique et sur les facteurs de risque de cardiopathie dans l'agglomeration de Teheran (etude sur le glucose et les lipides realisee a Teheran)

    Ramezankhani, A; Mirmiran, P; Azizi, F


    Dans une etude cas-temoins, une intervention nutritionnelle consistant en un programme educatif fonde sur les directives du regime de changement therapeutique de style de vie a ete mise en ceuvre dans...

  14. Investigation of molecular mechanisms in photodynamic action and radiobiology with nanosecond flash photolysis and pulse radiolysis. Progress report, 1982

    Grossweiner, L.I.


    Liposomes have been employed as membrane models applicable to photosensitization in phototherapy procedures. The results with 8-methoxypsoralen, the sensitizer in PUVA therapy of psoriasis, show that singlet oxygen generated by near-uv (uv-A) irradiation induces membrane damage leading to lysis. A similar role of singlet oxygen has been shown for photosensitization of liposomes by methylene blue, with the new observation that hydrodynamic forces promote the lytic action initiated by singlet oxygen attack on an unsaturated site of phosphatidylcholine. Liposome photosensitization by hematoporphyrin follows a Type II mechanism mediated by singlet oxygen for low sensitizer concentrations, and a Type I, anoxic, mechanism when the hematoporphyrin is aggregated. Similar concentration effects obtain with hematoporphyrin derivative (hpd), the photosensitizer in photoradiation therapy of malignant tumors. Studies on the components of hpd separated by gel chromatography show that the putative biological active fraction can photosensitize membrane damage under oxic and anoxic conditions. The oxic pathway was suppressed by binding to human serum albumin, as involved in serum transport of hpd prior to localization in tumor tissue. A study on hematoporphyrin photosensitization of targets other than membranes has shown that singlet oxygen is responsible for the photosensitized inactivation of subtilisin BPN' and photooxidation of tryptophan in human and bovine serum albumin. In the case of the serum proteins, the singlet oxygen is generated by the sensitizer-protein complex and it may react with all protein in the system. 11 references.

  15. Dosimetric and radiobiological consequences of computed tomography-guided adaptive strategies for intensity modulated radiation therapy of the prostate.

    Battista, Jerry J; Johnson, Carol; Turnbull, David; Kempe, Jeff; Bzdusek, Karl; Van Dyk, Jacob; Bauman, Glenn


    To examine a range of scenarios for image-guided adaptive radiation therapy of prostate cancer, including different schedules for megavoltage CT imaging, patient repositioning, and dose replanning. We simulated multifraction dose distributions with deformable registration using 35 sets of megavoltage CT scans of 13 patients. We computed cumulative dose-volume histograms, from which tumor control probabilities and normal tissue complication probabilities (NTCPs) for rectum were calculated. Five-field intensity modulated radiation therapy (IMRT) with 18-MV x-rays was planned to achieve an isocentric dose of 76 Gy to the clinical target volume (CTV). The differences between D95, tumor control probability, V70Gy, and NTCP for rectum, for accumulated versus planned dose distributions, were compared for different target volume sizes, margins, and adaptive strategies. The CTV D95 for IMRT treatment plans, averaged over 13 patients, was 75.2 Gy. Using the largest CTV margins (10/7 mm), the D95 values accumulated over 35 fractions were within 2% of the planned value, regardless of the adaptive strategy used. For tighter margins (5 mm), the average D95 values dropped to approximately 73.0 Gy even with frequent repositioning, and daily replanning was necessary to correct this deficit. When personalized margins were applied to an adaptive CTV derived from the first 6 treatment fractions using the STAPLE (Simultaneous Truth and Performance Level Estimation) algorithm, target coverage could be maintained using a single replan 1 week into therapy. For all approaches, normal tissue parameters (rectum V(70Gy) and NTCP) remained within acceptable limits. The frequency of adaptive interventions depends on the size of the CTV combined with target margins used during IMRT optimization. The application of adaptive target margins (adaptive CTV determined 1 week into therapy minimizes the need for subsequent dose replanning. Copyright © 2013 Elsevier Inc. All rights reserved.

  16. Study of the artificial radioactivity of the marine medium using gamma spectrometry (1962-1966); Etude de la radioactivite artificielle du milieu marin par spectrometrie gamma (1962-1966)

    Chesselet, R. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    The results described in this study are relative to the artificial radioactivity of such elements as zirconium-95, niobium-95, ruthenium-103, ruthenium-106, cerium-141, cerium-144 and praseodymium-144 which were present in the atmospheric fallout between 1962 and 1964, and their incidence in superficial marine waters. Various physical, chemical or biological processes are studied by a high sensitivity gamma ray spectrometry technic, using those radioelements as 'tracers'. The change of state in sea water of an important fraction (about 50 per cent) of the radioactive particles going into the soluble phase - this phenomenon was not expected for those radioelements - controls the processes of accumulation in the planktonic biomass and the diffusion towards deeper waters. On the other hand, an 'in situ' spectrometry method is described. It enables the direct measurement in the sea of very low concentrations of some gamma ray emitters. The application of this method has made possible to carry out numerous observations in the surface waters of the Western Mediterranean sea and in the Bay of Biscay. It is shown that the mixing depth is closely connected to the depth of the thermocline. An accumulation process at this level is observed. The diffusion coefficients are similar to the thermal turbulent coefficient. The existence during several months of 'compartments' is established for the surface waters of the Bay of Biscay. From the establishment of the budget of fall-out, a comparative study shows that the rate of radioactive fallout on the maritime zone considered is always two to three times higher than on the neighbouring continental regions. Several explanations of this phenomenon are discussed. (author) [French] Les resultats decrits dans cette etude concernent la radioactivite artificielle sous forme de zirconium-95, niobium-95, ruthenium-103, ruthenium-106, cerium-141, cerium-144 et praseodyme-144 apportee par la retombee

  17. SU-E-T-69: A Radiobiological Investigation of Dose Escalation in Lower Oesophageal Tumours with a Focus On Gastric Toxicity

    Carrington, R [Cardiff University, Cardiff, Wales (United Kingdom); Staffurth, J; Spezi, E; Crosby, T [Velindre Cancer Centre, Cardiff, Wales (United Kingdom); Warren, S; Partridge, M; Hawkins, M [CRUK/MRC Oxford Institute for Radiation Oncology, Oxford (United Kingdom); Gwynne, S [Singleton Hospital, Swansea, Wales (United Kingdom)


    The incidence of lower third oesophageal tumours is increasing in most Western populations. With the role of radiotherapy dose escalation being identified as a research priority in improving outcomes, it is important to quantify the increased toxicity that this may pose to sites such as the lower oesophagus. This study therefore aims to investigate the feasibility of lower oesophageal dose escalation with a focus on stomach tissue toxicity.The original 3D-conformal plans (50Gy3D) from 10 patients in the SCOPE1 trial were reviewed and compared to two RapidArc plans created retrospectively to represent the treatment arms of the forthcoming SCOPE2 trial: 50GyRA and 60GyRA (50Gy to PTV1 with a simultaneously integrated boost of 60Gy to PTV2). The stomach was contoured as stomach wall and dose constraints set according to QUANTEC. Normal tissue complication probability (NTCP) was estimated for the stomach wall for an endpoint of gastric bleeding. There was a mean increase of 5.93% in NTCP from 50Gy3D to 60GyRA and a mean increase of 8.15% in NTCP from the 50GyRA to 60GyRA. With NTCP modelling restricted to volumes outside PTV2, there was a mean decrease of 0.92% in NTCP from the 50Gy3D to 60GyRA, and a mean increase of 2.25% from 50GyRA to 60GyRA. There was a strong correlation between the NTCP and Stomach Wall/PTV1 overlap volume for all plans (R=0.80, 0.77 and 0.77 for 60GyRA, 50GyRA and 50Gy3D respectively). There was also a strong correlation between NTCP and the Stomach Wall/PTV2 overlap volume for 60GyRA (R= 0.82).Radiobiological modelling suggests that increasing the prescribed dose to 60Gy may be associated with a significantly increased risk of toxicity to the stomach within the boost volume. It is recommended that stomach toxicity be closely monitored prospectively when treating patients with lower oesophageal tumours in the forthcoming SCOPE 2 trial. Rhys Carrington received a PhD studentship grant from Cancer Research Wales. Grant number: 2445; Dr Warren and

  18. Development of a slow mono-kinetic electron source; Etude et realisation d'une source d'electrons lents monocinetiques

    Ballu, Y. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    A comparative study of already existing slow mono-kinetic electron guns shows that those using a 127 degrees electrostatic selector can be improved still further to arrive at the performances obtained with spherical 180 degrees selectors for example. For this reason we have examined the 127 degrees selector theoretically in more detail; it appears that it should be possible to obtain a resolving power better than 30 mV for a current of about 10{sup -10} A, on condition that certain improvements be made to the instrument as normally designed, in particular concerning the entrance and exit slides. As a result, the usual suppressors for the scattered electrons are no longer necessary. The development of this apparatus has been carried out with particular care: the dimensional characteristics are fixed to an accuracy of a few microns, although the instrument can be baked out at 300 C. The experimental results are in excellent agreement with the theoretical predictions: for a current of 10{sup -10} A, the measured resolving power is 24 {+-} 4 mV. The easy detection of the He{sup -} resonance line at 19.3 eV has confirmed the advantages of this apparatus for the study of atomic collisions. (author) [French] L'etude comparative des canons a electrons lents monocinetiques realises jusqu'a present montre que ceux qui utilisent un selecteur electrostatique a 127 degres peuvent etre encore perfectionnes en vue de parvenir aux performances obtenues avec les selecteurs spheriques a 180 degres par exemple. D'ou notre etude theorique approfondie du selecteur a 127 degres qui nous a conduit a esperer une resolution meilleure que 30 mV pour un courant de l'ordre de 10{sup -10} A a condition d'apporter certaines ameliorations a la conception usuelle de cet instrument notamment au niveau des fentes d'entree et de sortie. Par voie de consequence les suppresseurs habituels d'electrons parasites deviennent inutiles. L'etude et la mise au point de

  19. For a return to the Etudes sur les sciences sociales. Local autonomy and territorial wealth according to Sismondi

    Giuseppe Pioletti


    Full Text Available The article aims to analyse the Etudes sur les sciences sociales, published by Sismondi between 1836 and 1838, conducted in the light of the theses not only of the historians of Italian thinking who have determined the revival of interest in the Genevan’s doctrine, but also of very relevant works on issues of the growth and degrowth of the world economy. In particular, Pioletti focuses attention on the question of the territories: for the social scientist Sismondi at the end of the 1830s, they are functional and ideally constitutional units, where rules and customs apply that alone can deal with the risks of haphazard economic growth. Small localities, small estates: from these elements Sismondi also draws inspiration for an original theory of government – and for the national and local relations in the modern States – which, albeit presenting itself in 1836, was clearly affected by an interest that had been manifested in the historiographic field from 1807.

  20. Method of research and study of uranium deposits; Methode de recherches et d'etude des gites uraniferes

    Lenoble, A. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    In a first part, the author gives a fast retrospective of the evaluations of the uranium deposits in the French Union. The author established a method of prospecting and studying, modifiable at all times following the experiences and the results, permitting to make the general inventory of uranium resources on the territory. The method is based on: 1 - the determination of geological guides in order to mark the most promising deposits, 2 - the definition of a methodology adapted to every steps of the research, 3 - the choice of the material adapted for each of the steps. This method, originally established for the prospecting in crystalline massifs, is adaptable to the prospecting of the sedimentary formations. (M.B.) [French] Dans une premiere partie, l'auteur donne une retrospective rapide des estimations des gites uraniferes dans l'Union Francaise. L'auteur a etabli une methode de prospection et d'etude, modifiable a tout instant suivant les experiences et les resultats, permettant de faire l'inventaire general des ressources en uranium du territoire. La methode est base sur: 1 - la determination de guides geologiques afin de reperer les gisements les plus prometteurs, 2 - la definition d'une methodologie adaptee a chaque stade de la recherche, 3 - le choix du materiel adapte pour chacun des stades. Cette methode, a l'origine etablie pour la prospection en massifs cristallins, est adaptable a la prospection des formations sedimentaires. (M.B.)

  1. Radiobiological and genetic effects of Bromus inermis seed progeny from populations of the East-Ural Radioactive Trace (Russia, Kyshtym accident) - Radiobiological and genetic effects for Bromus inermis Leyss. Populations at the East-Ural radioactive trace (Russia, Kyshtym accident in 1957)

    Antonova, Elena V.; Pozolotna, Vera N. [Institute of Plant and Animal Ecology UB RAS, 8 Marta str. 202, 620144, Ekaterinburg (Russian Federation); Karimullina, Elina M. [Institute of Plant and Animal Ecology UB RAS, 8 Marta str. 202, 620144, Ekaterinburg (Russian Federation); Department of Developmental and Cell Biology, University of California, 2011 Biological Sciences III, Irvine, CA 92697-2300 (United States); Roeder, Marion S. [Leibniz Institute of Plant Genetics and Crop Plant Research, Corrensstrasse 3, D-06466, Gatersleben (Germany)


    This investigation dedicates the problem of remote consequences of radiation impact on plant populations. This is a part of a complex research, which includes the classic triad of radioecology (Timofeev-Ressovsky 1963): 'accumulation and migration of radionuclides in different components of ecosystems - assessment of radiation dose - investigation of radiobiological effects'. We used the populations of smooth brome (Bromus inermis Leyss.) as a model system for the investigation of radiobiological and genetic effects. It is radiosensitive plant (Preobrazhenskaya 1971). These species may be used as objects for bio-indication at the radioactive contaminated areas, and as well as large-scale radioecological studies, because the adaptation processes are faster for radiosensitive species (Shevchenko et al., 1992; Pozolotina et al. 2005). We calculated external and internal whole-body dose rates by ERICA Tool (Karimullina et al., 2013). The total dose rate for brome was under 100 mGy h{sup -1} at the most polluted site but 43-110 times (Tier 3) exceeded the background along the pollution gradient. Therefore it can be concluded that herbaceous plant populations currently exist under low level chronic exposure at the EURT area. During seven years we have studied variability of viability, mutability and radioresistance of brome seed progeny. The combined effects of radiation exposure and weather conductions at the EURT area were absent. It may be connect with wide variability of inter-population test parameters. At the same time the weather conductions had an influence on the quality of seed progeny at the background area. We analyzed also correlation between original viability and radioresistance of seed progeny from the all plots. This dependence was positive. It was shown negative dependence between original viability of seed progeny and low weight molecular antioxidants content too. Ionizing radiation is a mutagenic factor and, accordingly, elevated mutation

  2. Apprendre et maîtriser LabVIEW par ses applications

    Martaj, Nadia


    Cet ouvrage traite de l'apprentissage du langage LabVIEW a travers ses applications dans des domaines industriels et academiques, qui permettront a l'ingenieur, technicien ou etudiant d'apprehender rapidement et efficacement ce langage. L'ouvrage commence, dans la partie I, par traiter les differents types de donnees du langage LabVIEW (tableaux, clusters, complexes, chaines de caracteres...), leur manipulation dans des structures d'execution (boucles While, For, la structure Condition, etc.), le langage textuel MathScript, des scripts Matlab, la boite de calcul utilisant la syntaxe du langage C ainsi que les nœuds de propriete qui permettent d'obtenir ou definir la propriete d''un VI. Cette etude est menee a travers des applications d'ingenierie.La partie II est consacree a l'etude de l'outil « Conception de controle et simulation » avec lequel nous pouvons simuler des systemes analogiques ou discrets.La partie III contient differentes applications qui traitent de nombreux themes comme la regulation (diff...

  3. Methods for studying the radioactive contamination of plants (1963); Methodes d'etude de la contamination radioactive des vegetaux (1963)

    Coulon, R.; Jeanmaire, L.; Michon, G. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires


    The authors first define the doctrine which led to the devising of a method for studying the radioactive pollution of plants, based on the use of simple techniques, having the possibility of being adapted for routine work, and so devised that each stage is proceeded with only if the preceding one justifies it. For each stage a study is effected comparing the results obtained by the use of more exact techniques. The second part describes in detail the techniques used. (authors) [French] Dans une premiere partie lea auteurs definissent la doctrine qui leur a permis d'elaborer une methode d'etude de la pollution radioactive des vegetaux, basee sur l'utilisation de techniques simples, se pretant au travail de serie et concues de telle maniere que chaque etape n'est abordee que si la precedente le justifie. Chaque etape fait l'objet d'une etude qui compare les resultats a ceux obtenue par des techniques plus precises. La deuxieme partie decrit dans le detail les techniques utilisees. (auteurs)

  4. Shot noise in radiobiological systems.

    Datesman, A


    As a model for human tissue, this report considers the rate of free radical generation in a dilute solution of water in which a beta-emitting radionuclide is uniformly dispersed. Each decay dissipates a discrete quantity of energy, creating a large number of free radicals in a short time within a small volume determined by the beta particle range. Representing the instantaneous dissipated power as a train of randomly-spaced pulses, the time-averaged dissipated power p¯ and rate of free radical generation g¯ are derived. The analogous result in the theory of electrical circuits is known as the shot noise theorem. The reference dose of X-rays Dref producing an identical rate of free radical generation and level of oxidative stress is shown a) to increase with the square root of the absorbed dose, D, and b) to be far larger than D. This finding may have important consequences for public health in cases where the level of shot noise exceeds some noise floor corresponding to equilibrium biological processes. An estimate of this noise floor is made using the example of potassium-40, a beta-emitting radioisotope universally present in living tissue.

  5. SU-C-BRE-02: BED Vs. Local Control: Radiobiological Effect of Tumor Volume in Monte Carlo (MC) Lung SBRT Planning

    Pokhrel, D; Badkul, R; Jiang, H; Estes, C; Park, J; Kumar, P; Wang, F [UniversityKansas Medical Center, Kansas City, KS (United States)


    Purpose: SBRT with hypofractionated dose schemata has emerged a compelling treatment modality for medically inoperable early stage lung cancer patients. It requires more accurate dose calculation and treatment delivery technique. This report presents the relationship between tumor control probability(TCP) and size-adjusted biological effective dose(sBED) of tumor volume for MC lung SBRT patients. Methods: Fifteen patients who were treated with MC-based lung SBRT to 50Gy in 5 fractions to PTVV100%=95% were studied. ITVs were delineated on MIP images of 4DCT-scans. PTVs diameter(ITV+5mm margins) ranged from 2.7–4.9cm (mean 3.7cm). Plans were generated using non-coplanar conformal arcs/beams using iPlan XVMC algorithm (BrainLABiPlan ver.4.1.2) for Novalis-TX with HD-MLCs and 6MVSRS(1000MU/min) mode, following RTOG-0813 dosimetric guidelines. To understand the known uncertainties of conventional heterogeneities-corrected/uncorrected pencil beam (PBhete/ PB-homo) algorithms, dose distributions were re-calculated with PBhete/ PB-homo using same beam configurations, MLCs and monitor units. Biologically effective dose(BED10) was computed using LQ-model with α/β=10Gy for meanPTV and meanITV. BED10-c*L, gave size-adjusted BED(sBED), where c=10Gy/cm and L=PTV diameter in centimeter. The TCP model was adopted from Ohri et al.(IJROBP, 2012): TCP = exp[sBEDTCD50]/ k /(1.0 + exp[sBED-TCD50]/k), where k=31Gy corresponding to TCD50=0Gy; and more realistic MC-based TCP was computed for PTV(V99%). Results: Mean PTV PB-hete TCP value was 6% higher, but, mean PTV PB-homo TCP value was 4% lower compared to mean PTV MC TCP. Mean ITV PB-hete/PB-homo TCP values were comparable (within ±3.0%) to mean ITV MC TCP. The mean PTV(V99%)had BED10=90.9±3.7%(median=92.2%),sBED=54.1±8.2%(median=53.5%) corresponding to mean MC TCP value of 84.8±3.3%(median=84.9%) at 2- year local control. Conclusion: The TCP model which incorporates BED10 and tumor diameter indicates that radiobiological

  6. Clinical and radiobiological advantages of single-dose stereotactic light-ion radiation therapy for large intracranial arteriovenous malformations. Technical note.

    Andisheh, Bahram; Brahme, Anders; Bitaraf, Mohammad A; Mavroidis, Panayiotis; Lind, Bengt K


    Radiation treatment of large arteriovenous malformations (AVMs) remains difficult and not very effective, even though seemingly promising methods such as staged volume treatments have been proposed by some radiation treatment centers. In symptomatic patients harboring large intracranial AVMs not amenable to embolization or resection, single-session high-dose stereotactic radiation therapy is a viable option, and the special characteristics of high-ionization-density light-ion beams offer several treatment advantages over photon and proton beams. These advantages include a more favorable depth-dose distribution in tissue, an almost negligible lateral scatter of the beam, a sharper penumbra, a steep dose falloff beyond the Bragg peak, and a higher probability of vascular response due to high ionization density and associated induction of endothelial cell proliferation and/or apoptosis. Carbon ions were recently shown to be an effective treatment for skull-base tumors. Bearing that in mind, the authors postulate that the unique physical and biological characteristics of light-ion beams should convey considerable clinical advantages in the treatment of large AVMs. In the present meta-analysis the authors present a comparison between light-ion beam therapy and more conventional modalities of radiation treatment with respect to these lesions. Dose-volume histograms and data on peripheral radiation doses for treatment of large AVMs were collected from various radiation treatment centers. Dose-response parameters were then derived by applying a maximum likelihood fitting of a binomial model to these data. The present binomial model was needed because the effective number of crucial blood vessels in AVMs (the number of vessels that must be obliterated to effect a cure, such as large fistulous nidus vessels) is low, making the Poisson model less suitable. In this study the authors also focused on radiobiological differences between various radiation treatments. Light

  7. Preliminary studies on the Marcoule site, using a wind-tunnel; Etude preliminaire en soufflerie du site de Marcoule

    Chassany, J.Ph. [Commissariat a l' Energie Atomique, Service de Protection contre les Radiations, Marcoule (France). Centre d' Etudes Nucleaires; Parigi, H. [Institut de Mecanique des Fluides, 13 - Marseille (France); Salaun-Penquer, G. [Centre National de la Recherche Scientifique (CNRS), 13 - Marseille (France)


    The tests were carried out in the 3.30 x 2.20 subsonic elliptical wind-tunnel of the Marseille Institute of fluid mechanics, on a 1/1000 scale model measuring 3 m x 3 m. The aerodynamic field developing above the site, made visible by ammonium, hydro-chlorate fumes, and the residues were observed and filmed by means of a synchronised cine-camera with stroboscopic lighting for 4 wind directions. The fall-out from the various waste products was obtained from a spraying of lead acetate solution on the model and hydrogen sulphide emissions. The zones of maximum pollution can be determined from a study of the film taken during the blackening of the spots. (author) [French] Les essais ont ete effectues dans la soufflerie elliptique subsonique de 3,30 x 2,20 de l'Institut de Mecanique des fluides de Marseille, sur une maquette, a l'echelle 1/1000, de 3 m x 3 m. Le champ aerodynamique se developpant au-dessus du Site, visualise par des fumees de chlorydrate d'ammoniaque ainsi que les rejets ont ete observes et filmes avec une camera synchronisee avec un eclairage stroboscopique pour 4 directions du vent. Les retombees au sol provenant des differents rejets ont ete obtenues a partir de la pulverisation d'une solution d'acetate de plomb sur la maquette et d'emissions de sulfure d'hydrogene. L'etude du film pris au cours du noircissement des taches permet de determiner les zones de pollution maximales. (auteur)

  8. Systematic study of plasma and serum proteins in the pig; Etude systematique des proteines plasmatiques et seriques du porc

    Daburon, F.; Nizza, P.; Hatchikian, C.; Schmidt, J.-P. [Commissariat a l' Energie Atomique (France)


    This work has been carried out in the framework of the determination of the physiological constants of a normal pig. The aim was to study the serum and plasma proteins of this animal species, the ultimate object being to discover whether the qualitative and quantitative changes in these proteins can make a significant contribution to the establishment of a biological dosimetry for irradiated pigs. The serum and plasma from a normal pig were analyzed first by various simple electrophoretic methods and then by immuno-electrophoresis. As a result of the particular characteristics of pig serum we have gradually been led to make numerous modifications to the techniques used for human serums or for those of small laboratory animals. Much careful work and patience were required in order to obtain reproducible results. (authors) [French] Ce travail se situe dans le cadre de la determination des constantes physiologiques du porc normal. il s'agissait de proceder a l'etude des proteines seriques et plasmatiques de cette espece animale, le but ulterieur etant de savoir si les modifications qualitatives et quantitatives de ces proteines pourront representer une contribution valable a l'etablissement d'une dosimetrie biologique chez le porc irradie. Le serum et le plasma du porc normal ont ete analyses d'abord par diverses methodes electrophoretiques simples puis par immunoelectrophorese. Les caracteristiques particulieres du serum de porc nous ont conduits a apporter progressivement de nombreuses modifications aux techniques utilisees pour des serums humains ou de petits animaux de laboratoire. L'obtention de resultats reproductible a exige beaucoup de patience et de minutie. (auteurs)

  9. Composes inter-halogenes sous pression: etude des transformations structurales dans le monobromure d'iode sous forme dense

    Bouchard, Alexandre

    La famille des composes halogenes et inter-halogenes representent des solides moleculaires adoptant des phases denses communes avec des solides moleculaires diatomiques comme l'azote et l'hydrogene. Parmi les transformations structurales et electroniques induites sous haute pression et observees dans ces solides, on note, entre autres, la dissociation moleculaire et la metallisation. De plus, l'etude des phases denses de l'iode a permis recemment l'observation d'une structure cristalline possedant une modulation dite incommensurable, c'est-a-dire une modulation possedant une periodicite differente de celle de la structure cristalline, jetant ainsi une lumiere nouvelle sur le processus de dissociation moleculaire dans les solides halogenes. Dans ce memoire, on propose d'etudier les changements structuraux dans monobromure d'iode (IBr), un compose inter-halogene possedant des proprietes structurales semblables a celles de deux composes halogenes, soit l'iode (I 2) et le brome (Br2) sous leur forme solide. Des experiences de diffraction des rayons X de poudres en utilisant un rayonnement synchrotron ont ete realisees a temperature ambiante sur l'IBr en variant la pression jusqu'aux environs de 60 GPa. La nature chimique particuliere du compose IBr a necessite la mise au point de techniques de chargement d'echantillon destinees a preserver l'integrite chimique de la substance utilisee. On rapporte egalement l'observation d'une phase de l'IBr presentant une modulation incommensurable. Les phases observees dans l'IBr permettent d'etablir des paralleles avec les phases denses rapportees dans I2 et Br2 par le biais d'un modele phenomenologique decrivant la sequence structurale des solides halogenes sous forme condensee.

  10. Etude d'interrupteurs en carbure de silicium et potentiel d'utilisation dans des applications aéronautiques

    Othman, Dhouha


    The potential of wide band gap transistors based on silicon carbide are remarkable and open new prospects for improvement (high efficiency, high breakdown voltage, high switching frequency and high operating temperature ...). This leads to volume and weight reduction for future converters. In order to improve new generation of power converters for future needs, Thales, in cooperation with SATIE and LTN IFSTTAR laboratories, performs investigations on the performances, advantages and disadvant...

  11. Etude de nouvelles réactions radicalaires : Application à la synthèse d'alcaloïdes.

    Gennet, Dominique


    The chemistry of nitrogen radicals is useful for synthesising numerous alkaloids in a simple and fast fashion. During this work, a new route to 2-imidazolines, precursors of imidazoles and vicinyl-diamines using amidinyl and stannyl radicals was explored and further extended towards other group transfers. In addition, a new methodology for generating amidyl radicals was also developed, based on the use of hydroxamyl xanthates. Finally, an attempt to synthesise the aspidospermidine, whose skel...




    Full Text Available Dans un espace topologique X, on considère une famille  γ non-vide de compacts de  X. A l’aide de cette famille, nous munissons C(X (l’ensemble des fonctions réelles continues sur X d’une topologie Set-Open. Muni de cette topologie, C(X sera noté . sur X, on définit deux jeux topologiques introduits par R.A. McCoy & I. Ntantu que nous associons à un jeu de Banach-Mazur sur pour donner une condition nécessaire pour que soit faiblement-α-favorable.

  13. Silicon P.I.N. Junctions used for studies of radiation damage; Etude de l'irradiation aux neutrons rapides du silicium au moyen de jonctions P.I.N

    Lanore, J. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires


    Irradiation of silicon P.I.N. junction has been studied primarily for the purpose of developing a radiation damage dosimeter, but also for the purpose of investigating silicon itself. It is known that the rate of recombination of electrons and holes is a linear function of defects introduced by neutron irradiation. Two methods have been used to measure that rate of recombination: forward characteristic measurements, recovery time measurements. In order to explain how these two parameters depend on recombination rate we have given a theory of the P.I.N. junction. We have also given an idea of the carrier lifetime dependence versus temperature. Annealing effects in the range of 70 to 700 K have also been studied, we found five annealing stages with corresponding activation energies. As an application for these studies, we developed a radiation damage dosimeter with which we made several experiments in facilities such as Naiade or Marias. (author) [French] L'irradiation de structures P.I.N. etait faite dans le but d'etudier principalement la mise au point d'un dosimetre a ''radiation damage'' et aussi pour etudier plus profondement le silicium lui-meme. On sait que le taux de recombinaison electrons-trous est une fonction lineaire du taux de defauts introduits par irradiation aux neutrons. Deux methodes ont ete utilisees pour atteindre ce taux de recombinaison: mesures de la caracteristique directe, mesures du temps de retournement. Pour expliquer de quelle facon ces parametres dependent du taux de recombinaison. Nous avons donne une theorie de la jonction P.I.N. Nous avons aussi donne l'allure des variations du temps de vie des porteurs en fonction de la temperature. Nous avons d'autre part effectue des recuits entre 70 et 700 K, domaine dans lequel nous avons trouve cinq etapes de ''guerison'' avec les energies d'activation correspondantes. En application de ces etudes nous avons mis ou point un

  14. Reconstruction de la surface de Fermi dans l'etat normal d'un supraconducteur a haute Tc: Une etude du transport electrique en champ magnetique intense

    Le Boeuf, David

    Des mesures de resistance longitudinale et de resistance de Hall en champ magnetique intense transverse (perpendiculaire aux plans CuO2) ont ete effectuees au sein de monocristaux de YBa2Cu3Oy (YBCO) demacles, ordonnes et de grande purete, afin d'etudier l'etat fondamental des supraconducteurs a haute Tc dans le regime sous-dope. Cette etude a ete realisee en fonction du dopage et de l'orientation du courant d'excitation J par rapport a l'axe orthorhombique b de la structure cristalline. Les mesures en champ magnetique intense revelent par suppression de la supraconductivite des oscillations magnetiques des resistances longitudinale et de Hall dans YBa2Cu 3O6.51 et YBa2Cu4O8. La conformite du comportement de ces oscillations quantiques au formalisme de Lifshitz-Kosevich, apporte la preuve de l'existence d'une surface de Fermi fermee a caractere quasi-2D, abritant des quasiparticules coherentes respectant la statistique de Fermi-Dirac, dans la phase pseudogap d'YBCO. La faible frequence des oscillations quantiques, combinee avec l'etude de la partie monotone de la resistance de Hall en fonction de la temperature indique que la surface de Fermi d'YBCO sous-dope comprend une petite poche de Fermi occupee par des porteurs de charge negative. Cette particularite de la surface de Fermi dans le regime sous-dope incompatible avec les calculs de structure de bande est en fort contraste avec la structure electronique presente dans le regime surdope. Cette observation implique ainsi l'existence d'un point critique quantique dans le diagramme de phase d'YBCO, au voisinage duquel la surface de Fermi doit subir une reconstruction induite par l'etablissement d'une brisure de la symetrie de translation du reseau cristallin sous-jacent. Enfin, l'etude en fonction du dopage de la resistance de Hall et de la resistance longitudinale en champ magnetique intense suggere qu'un ordre du type onde de densite (DW) est responsable de la reconstruction de la surface de Fermi. L'analogie de

  15. Therapeutic Applications of Monte Carlo Calculations in Nuclear Medicine

    Sgouros, George


    This book examines the applications of Monte Carlo (MC) calculations in therapeutic nuclear medicine, from basic principles to computer implementations of software packages and their applications in radiation dosimetry and treatment planning. It is written for nuclear medicine physicists and physicians as well as radiation oncologists, and can serve as a supplementary text for medical imaging, radiation dosimetry and nuclear engineering graduate courses in science, medical and engineering faculties. With chapters is written by recognised authorities in that particular field, the book covers the entire range of MC applications in therapeutic medical and health physics, from its use in imaging prior to therapy to dose distribution modelling targeted radiotherapy. The contributions discuss the fundamental concepts of radiation dosimetry, radiobiological aspects of targeted radionuclide therapy and the various components and steps required for implementing a dose calculation and treatment planning methodology in ...

  16. Study of the asymptotic expansion of multiple integrals in mathematical physics; Etudes sur les developpements asymptotiques des integrales multiples de la physique mathematique

    Chako, N. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    , provided one interprets in a proper manner the results derived from the two methods, especially the expression of the geometrical wave. (author) [French] Nous avons applique la methode de la phase stationnaire pour evaluer les integrales doubles et multiples du type: (A) U(k) = g(x)e{sup ik{phi}}{sup (x)} d(x), (x)=(x{sub 1},..., x{sub n}) pour les grandes valeurs du parametre k. Dans la premiere partie nous avons etendu d'une maniere rigoureuse la methode de la phase stationnaire aux integrales doubles et multiples de type (A). De plus, nous avons obtenu un developpement asymptotique de (A), lorsque l'amplitude et la phase peuvent se developper sous forme canonique au voisinage de points critiques ou stationnaires de l'integrale (A). Ce developpement contient comme cas particuliers tous les cas importants dans les applications physiques et particulierement en diffraction et diffusion d'ondes electromagnetiques et corpusculaires par des systemes optiques, corps diffractants et potentiels de diffusions. Dans la seconde partie nous avons considere le probleme de la convergence du developpement de la contribution principale a l'integrale, au sens asymptotique de Poincare. La preuve est basee sur la methode des majorantes, utilisee en analyse mathematique. La troisieme partie contient la derivation des series asymptotiques diverses, due aux types varies de points critiques ou stationnaires lies aux fonctions d'amplitude et de phase. Dans la quatrieme partie nous avons generalise la methode aux integrales multiples et au cas ou le parametre k entre implicitement dans la fonction de phase. Ce dernier type d'integrales permet l'extension du premier type a de nombreux problemes physiques, par exemple a la propagation d'ondes en milieux dispersifs et absorbants. Au dernier chapitre, nous faisons l'etude des integrales doubles de diffractions (theorie de Kirchhoff) et nous comparons les resultats par l'application de la methode

  17. Beach sediments drift study by means of radioactive tracers; L'etude du transport littoral par la methode des traceurs radioactifs

    Hours, R. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires; Jaffry, P. [Electricite de France (EDF), 78 - Chatou (France). Lab. National d' Hydraulique


    The present state of the sediments drift studies by means of radioactive tracers is exposed. Various processes of labelling, immersion and detection, used in France and other countries, are reviewed. A more extended analysis of some aspects of the problem by the same authors can be found in 'La Houille Blanche', number 3, may-june 1959 (Rapport C.E.A. number 1269). (author) [French] L'etude du transport littoral des sediments et galets par la methode des traceurs radioactifs est en plein developpement. Le present rapport precise l'etat actuel de la question. Les techniques de marquage, d'immersion et de detection utilisees en France et a l'etranger sont decrites; une analyse plus detaillee de certains aspects de la question est presentee par les memes auteurs dans 'La Houille Blanche', numero 3, mai-juin 1959 (Rapport C.E.A. numero 1269). (auteur)

  18. Contribution to the study of the vertical molten zone process (1963); Contribution a l'etude du procede de la zone fondue verticale (1963)

    Lenzin, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    Construction and use of several molten zone apparatuses operating either vertically or horizontally. Efficient purification of uranyl nitrate hexahydrate but less successful in the case of other hydrated double salts and of zirconyl chloride in the hydrochloric gel form. Demonstration and study of the dissymmetry in the direction of the transport of the impurity during, the purification by a vertical molten zone process. (author) [French] Construction et utilisation de plusieurs appareils de zone fondue travaillant soit en vertical, soit en horizontal. Purification efficace du nitrate d'uranyle hexahydrate mais peu significative dans le cas des autres couples de sels hydrates et du chlorure de zirconyle a l'etat de gel chlorhydrique. Mise en evidence et etude de la dissymetrie sur le sens de transport de l'impurete au cours de la purification par zone fondue verticale. (auteur)

  19. Experimental study of the hydrodynamic instabilities occurring in boiling-water reactors; Etude experimentale des instabilites hydrodynamiques survenant dans les reacteurs nucleaires a ebullition

    Fabreca, S. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires


    The subjects is an experimental out-of pile loop study of the hydrodynamic oscillations occurring in boiling-water reactors. The study was carried out at atmospheric pressure and at pressure of about 8 atmospheres, in channels heated electrically by a constant and uniform specified current. In the test at 8 atmospheres the channel was a round tube of approximately 6 mm interior diameter. At 1 atmosphere a ring-section channel was used, 10 * 20 mm in diameter, with an inner heating tube and an outer tube of pyrex. It was possible to operate with natural convection and also with forced convection with test-channel by-pass. The study consists of 3 parts: 1. Preliminary determination of the laws governing pressure-drop during boiling. 2. Determination of the fronts at which oscillation appears, within a wide range of the parameters involved. 3. A descriptive study of the oscillations and measurement of the periods. The report gives the oscillation fronts with natural and forced convection for various values of the singular pressure drop at the channel inlet and for various riser lengths. The results are presented in non-dimensional form, which is available, in first approximation, for all geometric scales and for all fluids. Besides the following points were observed: - the wall (nature and thickness) can be an important factor ; - oscillation can occur in a horizontal channel. (author) [French] II a ete effectue une etude experimentale, en boucle hors-pile, des oscillations hydrodynamiques survenant dans les reacteurs a ebullition. L'etude a ete effectuee a la pression atmospherique et a une pression voisine de 8 atmospheres dans des canaux chauffes electriquement a puissance imposee constante et uniforme. Dans les essais a 8 atmospheres le canal etait un tube circulaire de diametre interieur 6 mm environ. A 1 atmosphere le canal etait de section annulaire 10 * 20 mm avec un tube interieur chauffant et un tube exterieur en pyrex. Le fonctionnement etait possible

  20. Etude expérimentale des composés fluores et des phosphogypses rejetes en Baie de Seine-Rapport de synthèse


    Au cours de la deuxième phase du programme d'étude sur les lésions des poissons et mammifères marins, et dans le cadre de ce programme, les effets de divers effluents industriels rejetés en Baie de Seine ont été recherchés. Le présent rapport rassemble les résultats obtenus d'une part au terme des travaux effectués sur les composés fluorés et sur les phosphogypses et présentés en détail dans chacun des documents suivants : 1. Etude expérimentale chez Salmo gairdneri, des effets toxiques du fl...

  1. Randomized control trial for the assessment of the anti-albuminuric effects of topiroxostat in hyperuricemic patients with diabetic nephropathy (the ETUDE study).

    Kato, Sawako; Ando, Masahiko; Mizukoshi, Toshihiro; Nagata, Takanobu; Katsuno, Takayuki; Kosugi, Tomoki; Tsuboi, Naotake; Maruyama, Shoichi


    Proteinuria is an established risk factor for diabetic nephropathy. Recent studies indicate that some xanthine oxidase inhibitors have a renoprotective effect. The aim of this study was to assess whether topiroxostat reduces albuminuria in hyperuricemic patients with diabetic nephropathy and overt proteinuria. The ETUDE study is an ongoing 24-week, multicenter, open-label, randomized (1:1), parallel group study involving hyperuricemic patients with diabetic nephropathy (estimated glomerular filtration rate [eGFR] ≥ 20 mL/min/1.73 m(2)) and overt proteinuria (0.3 ≤ urine protein to creatinine ratio (UPCR) < 3.5 g/g Cr). Patients are randomly assigned to high dose (topiroxostat 160 mg daily) or low dose (topiroxostat 40 mg daily) on top of standard of care. The primary endpoint is the change in albuminuria indicated by urine albumin-to-creatinine ratio after 24 treated weeks relative to the baseline values. This trial was registered at the Japanese University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR: UMIN 000015403). The background, rationale, and study design of this trial are presented here. Seventy-six patients from four registered facilities have already been enrolled and received at least one dose of topiroxostat. This trial will end in 2017. The ETUDE trial is the first randomized controlled study of topiroxostat in hyperuricemic patients with diabetic nephropathy and overt proteinuria. We will clarify the pleiotropic function of topiroxostat including an anti-albumiuric effect as well as its effects on safely decreasing serum uric acid levels.

  2. Contribution to the study of deformed heavy nuclei by means of nuclear reactions; Contribution a l'etude des noyaux lourds deformes au moyen de reactions nucleaires

    Gastebois, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    The experimental results obtained in the study of the (d,p) reactions, at E{sub d} = 12 MeV, on the three even-even deformed nuclei {sup 170}Yb, {sup 172}Yb and {sup 174}Yb have been analysed in terms of DWBA calculations. The spectroscopic information relative to the odd final nuclei have been compared with the predictions of the collective model and of the Nilsson's model. The effect of various parameters used in the DWBA analysis (form factors, optical wave functions) has been carefully studied. The observed differences between the three final nuclei are qualitatively reproduced in the experimental study of resonances, seen in excitation functions of elastically and inelastically scattered protons on the same target nuclei, and corresponding to analogue states in the three nuclei {sup 171}Lu, {sup 173}Lu and {sup 175}Lu. (author) [French] Les resultats experimentaux de l'etude des reactions (d.p) a E{sub d} = 12 MeV, sur les noyaux deformes pairs-pairs {sup 170}Yb, {sup 172}Yb et {sup 174}Yb ont ete interpretes dans le cadre de l'approximation de Born des ondes deformees. Les informations spectroscopiques relatives aux noyaux impairs finals ont ete comparees aux predictions du modele collectif et du modele de Nilsson, apres avoir examine avec soin l'influence des differents parametres (facteurs de forme, fonctions d'onde 'optiques') utilises lors de l'analyse. Les differences observees entre les trois noyaux finals sont qualitativement reproduites par les resultats experimentaux de l'etude de resonances dans les fonctions d'excitation de diffusion elastique et inelastique de protons sur les memes noyaux-cibles, lors de la recherche d'etats analogues dans les noyaux {sup 171}Lu, {sup 173}Lu et {sup 175}Lu. (auteur)

  3. A study by internal friction of defects produced in iron and nickel irradiated at very low temperatures; Etude au moyen du frottement interne des defauts crees par irradiation a tres basse temperature dans le fer et le nickel

    Keating-Hart, G. de [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires


    This work represents a contribution to the study of point defects in metals. After a brief review of the theory of internal friction we will discuss some technical innovations aimed at increasing the flexibility of the apparatus at our disposal. These innovations have allowed us to extend our range of measurements down to 20 deg. K. We will then discuss our experimental results. Firstly, we describe preliminary experiments on electron irradiated iron and the evidence for a laminar structure. Secondly, we present and account of the first measurements on nickel after neutron irradiation at 27 deg. K. We will compare the results with those obtained by other methods in this laboratory. Essentially we have observed transitory peaks at low temperature due to close Frenkel pairs and we have noticed the absence of a peak which would correspond to the magnetic after effect band of stage I{sub E}. An attempt is made to explain the disappearance of the observed peaks upon the application of an internal saturating magnetic field. (author) [French] Ce memoire constitue une contribution a l'etude des defauts ponctuels dans les metaux. Apres un bref apercu theorique sur le frottement interne, nous presenterons quelques realisations techniques destinees a accroitre les possibilites des instruments qui nous ont ete confies. Ces dernieres nous ont permis d'etendre la gamme des mesures jusqu'a 20 deg. K. Nous parlerons ensuite de nos resultats experimentaux. En premier lieu, ceux obtenus au cours de premieres experiences, sur le fer irradie aux electrons mettent en evidence des structures de laminage. En second lieu, nous exposerons les premieres mesures realisees sur du nickel irradie aux neutrons; nous comparerons ces resultats avec ceux obtenus par d'autres moyens experimentaux dans le laboratoire. Nous avons observe essentiellement des pics fugitifs a basse temperature dus aux paires proches de Frenckel et nous avons constate l'absence d'un pic

  4. Contribution to the study of internal friction in graphites; Contribution a l'etude du frottement interieur des graphites

    Merlin, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    A study has been made of the internal friction in different graphites between -180 C and +500 C using a torsion pendulum; the graphites had been previously treated thermo-mechanically, by neutron irradiation and subjected to partial annealings. It has been shown that there occurs: a hysteretic type dissipation of energy, connected with interactions between dislocations and other defects in the matrix; a dissipation having a partially hysteretic character which can be interpreted by a Granato-Luke type formalism and which is connected with the presence of an 'ultra-micro porosity'; a dissipation by a relaxation mechanism after a small dose of irradiation; this is attributed to the reorientation of bi-interstitials; a dissipation having the characteristics of a solid state transformation, this during an annealing after irradiation. It is attributed to the reorganization of interstitial defects. Some information has thus been obtained concerning graphites, in particular: their behaviour at low mechanical stresses, the nature of irradiation defects and their behaviour during annealing, the structural changes occurring during graphitization, the relationship between internal friction and macroscopic mechanical properties. (author) [French] L'etude du coefficient de frottement interieur au moyen d'un pendule de torsion entre -180 C et +500 C a ete realisee pour differents graphites apres des traitements thermo-mecaniques, des irradiations neutroniques et des guerisons partielles. Il a ete mis en evidence: une dissipation d'energie a caractere hysteretique, reliee aux interactions des dislocations avec les autres defauts de la matrice; une dissipation a caractere partiellement hysteretique, interpretable par un formalisme type Granato-Lucke et reliee a la presence d'une ''ultra-microporosite''; une dissipation par un mecanisme de relaxation, apres irradiation a faible dose, attribuee a la reorientation de di

  5. Etude numerique et experimentale de la reponse vibro-acoustique des structures raidies a des excitations aeriennes et solidiennes

    Mejdi, Abderrazak

    compte. Les modeles developpes ont permis de conduire plusieurs etudes parametriques sur les proprietes vibro-acoustiques des structures d'avions facilitant ainsi la tache des concepteurs. Dans le cadre de cette these, un article a ete publie dans le Journal of Sound and Vibration et trois autres soumis, respectivement aux Journal of Acoustical Society of America, International Journal of Solid Mechanics et au Journal of Sound and Vibration Mots cles : structures raidies, composites, vibro-acoustique, perte par transmission.

  6. Etude expérimentale et analyse probabiliste du comportement à la ...


    quantitativement à partir de l'application du modèle probabiliste à deux paramètres de Weibull. ... have been evidenced through analyses of their mechanical properties. ... structurelles des structures composites [4-5]. ..... stratifiés, celles-ci restent comparables à cell ...... composites manufacturing Composites Part A: Applied.

  7. Etude et simulation des groupes convertisseurs-machines synchrones a six phases

    Doyon, Jean-Francois

    Since many years, multiphase (n > 3) machines represent a growing research interest in the electrical machines domain. This type of machine can be used for many systems like automotive electrical traction, electric ship propulsion, wind farms or high-power industrial applications. Above all multiphase machines, the six phases wounded rotor synchronous machine brings a huge interest. Subsequently, using that kind of machine in any application requires a good understanding of the machine model and its respective converters. Hence, simulation represents a great way to study the behaviour and design of such applications that uses six phases wounded rotor synchronous machines. The present research concerns the study and simulation of six phase synchronous machinesconverters systems. From this project resulted the implementation of the six phases wound rotor salient pole synchronous machine in the Demos library of Matlab SimPowerSytems. In terms of study, a six phase machine electric drive is designed as well as a six phase machine implementation in a type 4 wind farm. The modeling of the six phase synchronous machine is fully detailed for the electrical part and the mechanical part. Then, the voltage source inverter electric drive with hysteresis control is conceived. Simulations of torque control, speed control and degraded mode of the machine are executed. The results illustrate the electric drive efficiency. This is followed by the type 4 wind turbine application of the machine. The wind farm is connected to a 120 kV grid, where a voltage drop fault appears at the 120 kV bar for a duration of six 60 Hz cycles. The results show a good operation of the regulators during the fault. This application is also subjected to a degraded mode, where results illustrate once again a good system regulation. Also, for the electric drive and the wind farm applications, a comparative study is made for the use of an asymmetrical versus symmetrical winding configuration of the machine

  8. \\'Etude de performance des syst\\`emes de d\\'ecouverte de ressources

    Abbes, Heithem; Dubacq, Jean-Christophe; Jemni, Mohamed


    The Desktop Grid offers solutions to overcome several challenges and to answer increasingly needs of scientific computing. This technology consists mainly in exploiting PC resources, geographically dispersed, to treat time consuming applications and/or important storage capacity requiring applications. However, as resources number increases, the need for scalability, self-organisation, dynamic reconfiguration, decentralization and performance becomes more and more essential. In this context, this paper evaluates the scalability and performance of P2P tools for registering and discovering services (Publish/Subscribe systems). Three protocols are used in this purpose: Bonjour, Avahi and Pastry. We have studied the behaviour of these protocols related to two criteria: the elapsed time for registrations services and the needed time to discover new services.

  9. The Nasa space radiation school, an excellent training in radiobiology and space radiation protection; La NASA space radiation summer school, une formation d'excellence en radiobiologie et radioprotection spatiale

    Vogin, G. [Centre Alexis-Vautrin, 54 - Nancy (France)


    The astronauts have to spend more time in space and the colonization of the moon and Mars are in the cross hairs of international agencies. The cosmic radiation from which we are protected on ground by atmosphere and by the terrestrial magnetosphere (.4 mSv/year according to Who) become really threatening since 20 km altitude, delivering an average radiation dose of a therapeutic kind to astronauts with peaks related to solar events. It is composed in majority of hadrons: protons (85%) and heavy ions (13%), but also photons (2%) of high energy (GeV/n)). the incurred risks are multiple: early ones(cataract, central nervous system damages, whole body irradiation) but especially delayed ones (carcinogenesis). The astronauts radiation protection turns poor and the rate of death risk by cancer returning from a mission on Mars has been estimated at 5%. The Nasa created in 2004 a summer school aiming to awareness young researchers to the space radiobiology specificities. Areas concerned as follow: radioinduced DNA damage and repair, cell cycle, apoptosis, bystander effect, genome instability, neuro degeneration, delayed effects and carcinogenesis in relation with radiation exposure. (N.C.)

  10. Etude de l'endoribonucléase de restriction RegB.

    Saïda, Fakhri


    The restriction endoribonuclease RegB from the bacteriophage T4 is involved in the transition between the early and the middle phase of the lytic cycle of the virus. RegB cleaves with an almost absolute specificity the GGAG sequence needed for the bacterial initiation of the translation. We characterized the toxicity level of RegB in the bacterium and presented new tools to bypass this problem. We also presented a biotechnological application of RegB for the design of a positive selection and...


    El Kazzi, Mario


    This thesis is on one of the main INL axes, the goal of which is to develop the growth procedures of thin oxide single crystal on silicon. These oxides are meant to replace the presently used amorphous gate oxide (SiOxNy and HfSixOyNz) by a high-κ oxide in future “sub 22nm” CMOS. Besides, the interest in controlling the growth of these oxides goes far beyond this oxide gate application. This know-how would be a technological breakthrough to develop monolithic integration on silicon. In this c...

  12. Studies on the gamma-gamma method. Definition of an apparatus for on-the-spot measurement of uranium ore densities; Etudes sur la methode gamma-gamma. Determination d'un appareillage pour la mesure en place de la densite des minerais d'uranium

    Czubek, J.A. [Institut de Recheches Nucleaires, Dept. 6, Cracovie (Poland); Guitton, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    The work described follows on to the research published in report CEA-R--2720 in march 1965. It includes: - experimental results obtained with a model composed of a constant density material (graphite); - the drawing-up of calibration curves using the similitude principle; - determination of the characteristics of a gamma-gamma probe, together with a discussion. The influence is studied of a certain number of parameters on the shape of the energy spectra of scattered radiation, and of the calibration curves: nature of the radioactive source, diameter of the probe area, source detector distance, geometrical shape of shielding between the source and the detector. An attempt is made to find a mathematical model for the calibration curve, for given conditions. Numerical applications make it possible to establish the optimum technical characteristics for a probe measuring the density with the smallest statistical error. (authors) [French] Les travaux decrits font suite aux etudes presentees dans le rapport CEA-R--2720 de mars 1965. Ils portent sur: - les resultats experimentaux obtenus sur un modele constitue d'un materiau de densite constante (graphite) ; - l'etablissement de courbes d'etalonnage a l'aide du principe de similitude; - la recherche et la discussion des caracteristiques d'une sonde gamma-gamma. L'influence d'un certain nombre de parametres sur la forme des spectres d'energie du rayonnement diffuse et des courbes d'etalonnage est etudiee: nature de la source radioactive, diametre du sondage, distance source-detecteur, forme geometrique du blindage entre la source et le detecteur. Pour des conditions determinees, le modele mathematique de la courbe d'etalonnage est recherche. Des applications numeriques permettent d'etablir les caracteristiques techniques optimales d'une sonde mesurant la densite avec la plus faible erreur statistique. (auteurs)

  13. Etude de validation du "Michigan alcoholism screening test" (MAST) en langue française

    Trisconi, Yves; Magnenat Pierre (Dir.),


    Le but de cette étude est de répondre aux 3 questions suivantes: - 1) Le test de MAST est-il applicable, dans sa traduction française, à la population d'un service de médecine interne d'un hôpital universitaire en Suisse romande ? - 2) Le test de MAST apporte-t-il des résultats concordants avec le diagnostic clinique d'une part, et avec les résultats tirés de la littérature d'autre part ? - 3) De quelles façons peut-on définir et choisir deux valeurs critiques du test afin d'optimaliser l'uti...

  14. EBT2 Dosimetry of X-rays produced by the electron beam from PFMA-3, a Plasma Focus for medical applications

    Ceccolini, Elisa; Mostacci, Domiziano; Sumini, Marco; Tartari, Agostino


    The electron beam emitted from the back of Plasma Focus devices is being studied as a radiation source for IORT (IntraOperative Radiation Therapy) applications. A Plasma Focus device is being developed to this aim, to be utilized as an X-ray source. The electron beam is driven to impinge on 50 {\\mu}m brass foil, where conversion X-rays are generated. Measurements with gafchromic film are performed to analyse the attenuation of the X-rays beam and to predict the dose given to the culture cell in radiobiological experiments to follow.

  15. Etude exploratoire des conceptions de la circulation sanguine aupres d'eleves de l'ordre collegial

    Robitaille, Jean-Marc

    Il existe peu d'etudes sur les conceptions touchant les domaines de la biologie, notamment sur les conceptions de la circulation sanguine Nous avons observe egalement l'absence de recherche menee aupres d'eleves de l'ordre collegial sur cette question. Nous avons voulu combler une lacune en menant une recherche sur les conceptions de la circulation sanguine aupres d'eleves de l'ordre collegial. Pour mener cette recherche nous nous sommes inspires d'une methode developpee par Treagust (1988). Le premier niveau de formulation didactique etablit l'architecture du systeme et la fonction nutritive de la circulation. Le second niveau de formulation didactique decrit et relie les parametres de la dynamique de la circulation et leur relation: Pression, Debit et Resistance. Le troisieme niveau de formulation didactique s'interesse au controle de la circulation du sang dans un contexte d'homeostasie qui implique la regulation de la pression arterielle. Nous avons construit un questionnaire en nous guidant sur les niveaux de formulation didactique et l'analyse des entrevues menees aupres de dix-huit eleves, representatifs de la population cible. Ce questionnaire fut administre a un echantillon de 2300 eleves disperses dans six colleges de la region de Montreal. Notre echantillon comprend des eleves inscrits a des programmes de l'ordre collegial en Sciences de la nature et en Techniques de la sante et qui n'ont pas suivi le cours sur la circulation sanguine. Notre analyse des reponses des eleves de notre echantillon aux questions sur le premier niveau de formulation didactique revele que la majorite des eleves considerent que le systeme circulatoire relie les organes les uns aux autres dans un circuit en serie. Notre analyse revele egalement que la majorite des eleves estiment que les nutriments sont extraits du sang par les organes selon un processus de selection base sur les besoins determines par la fonction de l'organe. Ces besoins sont differents selon les organes qui ne

  16. Contribution to the study of samarium-151 excited levels; Contribution a l'etude des niveaux excites du samarium-151

    Locard, P. [Commissariat a l' Energie Atomique, Centre d' Etudes Nucleaires de Grenoble, 38 (France)


    The nucleus of {sup 151}Sm, which has 89 neutrons, happens to be on the lower edge of the deformed nuclei of region II. Therefore, the study of its levels is very interesting for the verification of the goodness of the collective models for deformed nuclei when the deformation is small (we introduce these models in the first chapter). {sup 151}Sm has often been studied, but the direct gamma spectrum measured with a lithium drift-germanium detector (chapter 3) shows many high energy transitions which did not appear in the previous level schemes. In order to settle these transitions, we have undertaken gamma-gamma coincidence spectra (as well as sum-coincidence spectra) experiments with a scintillation spectrometer designed in our laboratory (chapter 2). The investigation of the intensities of these coincidences leads us to modify the last proposed level schemes: we suppress the levels at 405,5 and 650 keV, we add levels at 245,6 - 306,6 - 522 - 952 and 962 keV. We have also verified the multipolarities of the main transitions and measured the half-lives of a few levels (chapter 3) (we find a half-life of 1.1 {+-} 0.5 nanosecond for the level at 167,7 keV). In chapter 4, we compare our results to the predictions of the models described in chapter 1. (author) [French] Le noyau de {sup 151}Sm, qui possede 89 neutrons, se trouve a la limite inferieure des noyaux deformes de la region II. L'etude de ses niveaux excites est donc d'un interet tout particulier pour la verification de la validite des differents modeles collectifs pour les noyaux deformes, lorsque la deformation est petite (nous introduisons ces modeles dans un premier chapitre). Le {sup 151}Sm a deja fait l'objet de nombreuses etudes, mais le spectre gamma direct fait avec une jonction de germanium compense au lithium (chapitre 3), nous a montre l'existence d'un grand nombre de transitions de hautes energies qui ne sont pas placees dans les schemas proposes jusqu'a ce jour. Pour

  17. Theoretical study of properties due to the curvature in the toroid shape in magnetohydrodynamics; Etude theorique des proprietes dues a la courbure dans les configurations toriques en magnetohydrodynamique

    Adam, J.C. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires


    - We are considering a toroidal plasma centred around a closed {gamma}. When the rotational transform L/2{pi} approach an integer k if some specific relations are not satisfied curvature effects can become very important. When the rotational transform is created by current flowing in the plasma this happen if the coefficient a{sub k} of the Fourier expansion of curvature 1/R(s) of is non equal zero. One find then that the influence of a{sub k} is preponderant and that is possible to neglect all the other members of the series to study the neighbourhood of the corresponding equilibrium singularity. By developing an adapted coordinate system it is thus possible to take into account curvature effects at the lowest order. Equilibrium study bring us to introduce an equilibrium parameter {nu} {<=} 1 characterizing curvature effects. It is shown that the more {nu} is near of 1 the more shear and V{sup {phi}} quantities occurring in the stability criterion are important. Finally stability investigation show that the larger is the integer k the smaller is the domain of stability when L/2{pi} is near of k. (author) [French] Nous considerons un plasma toroidal centre autour d'une courbe fermee {gamma}. Lorsque la transformation rotationnelle L/2{pi} est voisine d'un nombre entier k, si certaines relations ne sont pas satisfaites, les effets de courbure peuvent devenir tres importants. Quand la transformation rotationnelle est cree par les courants circulant dans le plasma ceci se produit si le coefficient a{sub k} du developpement en serie de Fourier de la courbure 1/R(s) de {gamma} est non nul. On trouve alors que l'influence du k-ieme coefficient devient preponderante et il possible de negliger les autres termes pour etudier le voisinage de la singularite d'equilibre correspondante. En developpant un systeme de coordonnees adapte il est alors possible de tenir compte des le premier ordre des effets de courbure. L' etude de l'equilibre conduit a

  18. Etude experimentale des excitations topologiques de l'effet Hall quantique a nu = 1 dans les heterostructures semiconductrices a double puits quantique

    Charlebois, Serge

    De nombreux travaux theoriques et experimentaux ont ete publies sur les excitations topologiques de gaz electroniques bidimensionnels (GE2D), appellees skyrmions, dans le regime de l'effet Hall quantique a remplissage unitaire. On attend des excitations semblables appellees bimerons dans les systemes formes de deux GE2D couples. Contrairement au cas des GE2D simples, aucune experience n'a, a notre connaissance, presente la mesure d'une propriete specifique aux bimerons. Nous presentons dans cette these des travaux experimentaux ayant pour objectif l'etude d'excitations topologiques dans les heterostructures a double puits quantique. Une manifestation attendue (les bimerons est la presence d'une anisotropie dans la conductivite a travers une constriction. Nous avons concu un dispositif original a point de contact a trois grilles non-coplanaires. Ce dispositif a trois grilles a la particularite de permettre la creation d'une constriction etroite dans le double GE2D tout en permettant l'equilibrage de la densite electronique entre les deux puits dans l'etroit canal de conduction. Nous avons fabrique ce dispositif de taille submicronique par electrolithographie sur des heterostructures a double puits. Les dispositifs ainsi fabriques ont ete etudies a basse temperature (0.3K) et ont montre un fonctionnement conforme aux attentes. Les travaux n'ont pas permis de mettre en evidence une anisotropie de transport revelatrice de l'existence de bimerons. Cette these est a notre connaissance la premiere etude experimentale visant la realisation de l'experience d'anisotropie de transport et est ainsi une contribution significative a l'avancement des connaissances dans ce domaine. Les travaux theoriques que nous presentons ont permis de montrer l'effet des excitations topologiques sur la capacite grille-GE2D du systeme. Ces travaux ouvrent la voie de la detection des bimerons par l'intermediaire de la mesure de la capacite grille-GE2D ou encore de la susceptibilite electrique du

  19. Etude des mécanismes des réactions induites par les noyaux à halo de neutrons $^{11}Be$ (49,2 MeV/nucléon) et $ ^{6}He$ (41,5 MeéV/nucléon) sur le plomb en fonction de l'inélasticité des collisions

    Patois, Y


    Etude des mécanismes des réactions induites par les noyaux à halo de neutrons $^{11}Be$ (49,2 MeV/nucléon) et $ ^{6}He$ (41,5 MeéV/nucléon) sur le plomb en fonction de l'inélasticité des collisions

  20. Construction Et Etude De Tests En Regression. 1. Correction Du Rapport De Vraisemblance Par Approximation De Laplace En Regression Non-lineaire. 2. Test D'adequation En Regression Isotonique A Partir D'une Asymptotique Des Fluctuations De La Distance

    Tocquet, A S


    Construction Et Etude De Tests En Regression. 1. Correction Du Rapport De Vraisemblance Par Approximation De Laplace En Regression Non-lineaire. 2. Test D'adequation En Regression Isotonique A Partir D'une Asymptotique Des Fluctuations De La Distance

  1. Clinical and symptomatological study of pigs subjected to a lethal dose of integral gamma irradiation; Etude clinique et symptomatologique chez le porc soumis a une irradiation gamma totale a dose letale

    Vaiman, M.; Guenet, J.-L.; Maas, J.; Nizza, P


    Results are reported from a clinical and haematological study on a Corsican species of pigs wholly exposed to an approximately lethal dose of {gamma} radiation. The aim of this work was to examine the changes in the irradiation syndrome of irradiation for pigs to make it thus possible to devise further experiments, in particular in the therapeutic field. The dose received was 285 rads (measured as the absorption in the vertical antero-posterior medial plane). Data are presented on cyto-haematological changes in the blood circulating immediately after irradiation, and followed up to death, and changes in the medullary cytology after irradiation. The clinical picture of lethal radiation injury in swine is described. (authors) [French] Les auteurs rapportent les resultats d'une etude clinique et hematologique chez des porcs de race corse irradies in toto a dose sensiblement letale. Le but de cette etude etait de connaitre l'evolution du syndrome aigu d'irradiation chez le porc et de permettre ainsi le developpement d'experimentations ulterieures, en particulier dans le domaine therapeutique. La dose delivree etait de 285 rad (en dose absorbee au niveau du plan median vertical anteroposterieur. L'etude a porte essentiellement: 1. Sur les modifications cyclo-hematologiques du sang circulant immediatement apres l'irradiation, pour les differentes lignees cellulaires; l'evolution de ces modifications a ete notee jusqu'a la mort; 2. Sur les modifications de la cytologie medullaire apres irradiation (evolution du myelogramme et essai d'evaluation de la cellularite de la moelle osseuse);: 3. Sur les signes cliniques, d'ailleurs tres discrets, observes chez les porcs apres irradiation. (auteurs)

  2. Développement et politiques agro-alimentaires dans la région méditerranéenne. Rapport annuel 2002. Centre International de Hautes Etudes Agronomiques Méditerranéennes, Paris, 247

    Ronald Jaubert


    Full Text Available Le rapport annuel du Centre International de Hautes Etudes Agronomiques Méditerranéennes (CIHEAM n’est pas un rapport d’activité classique mais une analyse des politiques agroalimentaires, des échanges méditerranéens et du partenariat euroméditerranéen. C’est un ouvrage de référence, unique en son genre, utile à tous ceux, chercheurs, enseignants ou professionnels du développement s’intéressant à la production agricole méditerranéenne, aux échanges agro-alimentaires et à leurs régulations. ...

  3. Etude expérimentale par observation in-situ de la dynamique non-linéaire des fronts de solidification directionnelle eutectiques fibreux de l'alliage transparent succinonitrile-camphre

    Perrut, Mikael


    Encadrants : Silvère Akamatsu, Sabine Bottin-Rousseau Co-financement par le Centre National de la Recherche Scientifique (CNRS) et le Centre National d'Etudes Spatiales (CNES); We present an experimental investigation of the dynamics of fibrous non-faceted eutectic directional-solidification structures in semi-bulk samples. A transparent succinonitrile-d,camphor alloy is used. The whole structure is followed in real time using a new optical setup, which permits to observe the growth front in ...

  4. Theoretical study and practical application of the capillary film solar distiller; Etude theorique et application pratique du distillateur solaire a film capillaire

    Bouchekima, B. [Institut de Chimie Industrielle, Universite de Blida (Algeria); Gros, B. [Universite Paul Sabatier, Dept. Genie Chimique, 31 - Toulouse (France); Ouahes, R. [Laboratoire de Chimie Solaire, USTHB, El Alia (Algeria); Diboun, M. [Institut de Chimie Industrielle, USTHB, El Alia (Algeria)


    This paper presents theoretical considerations and results of experiments carried out with a capillary film multiple effect distiller.It is made up of identical evaporation-condensation cells. The brine to be evaporated is a film impregnating a fabric assumed to be very this and adhering by capillarity forces to the wall of the plate. This justifies the device name: DIstillet with a FIlm in CAPillary motion, it was designed and patented by R. and C. Ouahes and P. Le Goff. Its advantage resides in the reuse of latent heat of stream condensed in the one stage, for water evaporation in the subsequent stage. The research and development of this desalination process is carried out under the following aspects: modeling of heat and mass transfer, experimentation under direct solar radiation in South Algeria and technical development with the aim to optimise the efficiency of the distiller. (authors)

  5. Etude des defauts apparaissant dans les amenagements interieurs des avions d'affaires

    Charette, Emilie

    The evolution of the aeronautic industry led to the development of new materials for these high performance applications. Among other examples, composite sandwich structures are increasingly used for interior body panels of business airplanes. These structures are assembled and fixed to the fuselage using metallic inserts bonded inside the sandwich panels with an epoxy resin adhesive. A thin film of wood veneer covers the visible side of interior furniture in order to bring sophistication and esthetic to the interior design. However, due to multiple factors, surface defects frequently appear on the veneered side of the panel where inserts are located. Moreover the defects tend to appear months after the airplane delivery causing costly reparations. The sources of defects can be mechanical ( deformation due to an excessive tightening), chemical (shrinkage of the epoxy adhesive) or the result of hygrothermal exposition. It is therefore important to understand the source of such surface defects and ultimately prevent or control their appearance. The present thesis deals with defects from chemical and hygrothermal sources appearing on the composite panels used on the interior body of business jets after aging. The main objective was to identify and quantify phenomena causing the defects on the interior panels of business planes. This research project is the first part of a project sponsored by CRIAQ and NSERC. The interaction of several materials can lead to various phenomena causing the apparition of surface defects. The project was thus divided into three parts in order to study an increasingly complex problem. the first study deals with the characterization of the different constitutive materials taken separately. This first part focused on thermal, rheological and mechanical aspects of epoxy adhesives. It was shown that the two adhesives used have different mechanical properties and cure kinetic reactions. In addition, the mechanical properties of sandwich

  6. Gas permeability of cement based materials; Etude de la permeabilite au gaz des materiaux cimentaires

    Galle, Ch.; Pin, M. [CEA Saclay, Dept. d' Entreposage et de Stockage des Dechets (DCC/DESD/SESD), 91 - Gif-sur-Yvette (France); Daian, J.F. [Universite Joseph-Fourier, Grenoble I, (INPG/CNRS/IRD), 38 (France)


    cement based materials is one of the most important parameters for gas transport. A knowledge of the porous and microstructural properties is therefore necessary. On the whole, concrete materials behave similarly to pastes. The XDQ model serves to estimate the gas permeability of cement based materials as a function of water saturation. Application to various and extended cases should help adjust some parameters of the model and to confirm its robustness. (authors)

  7. Electronic temperature measurement on the deca II plasma using the Bremsstrahlung; Mesure de la temperature electronique du plasma de deca II par etude du rayonnement de freinage

    Dumas, A. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires


    The electronic temperature of the DECA II machine's plasma is determined by studying the Bremsstrahlung. Two types of detectors are used for this measurement, a set scintillator-photo-multiplicator and a photoelectric effect detector with a massive silver target. The method used is the classical 'absorbent method', The absorbents used are thin formvar foils whose thickness is between 600 and 12 500 angstrom. The measurements done in two different working conditions of the DECA II machine have given: Te {approx_equal} 200 eV in the first case and Te {approx_equal} 70 eV in the second case. (author) [French] Nous avons determine la temperature electronique du plasma de la machine DECA II par l'etude du rayonnement de freinage. Pour cette mesure nous avons utilise deux types de detecteurs: des ensembles scintillateur-photomultiplicateur et un detecteur a effet photoelectrique a cible massive en argent. La methode utilisee pour cette mesure est la classique methode des absorbants. Nous avons utilise des feuilles de format tres mince (de 600 a 12 500 angstrom) comme absorbant. Les mesures faites dans deux regimes de travail differents de la machine DECA II nous ont conduit a: Te {approx_equal} 200 eV dans un cas et Te {approx_equal} eV dans l'autre cas. (auteur)

  8. Early oesophageal cancer: results of a European multicentre survey. Group Européen pour l'Etude des Maladies de l'Oesophage.

    Bonavina, L


    Early oesophageal cancer has been extensively studied in Far-Eastern countries, where its prevalence is high. A multicentre survey was conducted within the Groupe Européen pour l'Etude des Maladies de l'Oesophage to analyse results of surgical treatment in patients with disease staged as pTis-T1 N0 M0 according to the tumour node metastasis classification. Of 9743 patients with squamous cell oesophageal carcinoma observed since 1980, 4663 underwent resection; 253 (5.4 per cent) of these fulfilled the criteria for inclusion in the study. The overall mortality rate was 9.1 per cent (23 patients), and was higher after transthoracic than transhiatal oesophagectomy (10.7 versus 6 per cent, P not significant). Pathological examination showed an intraepithelial tumour in 46 patients (18.2 per cent), intramucosal carcinoma in 64 (25.3 per cent) and a submucosal lesion in 143 (56.5 per cent). The overall 5-year survival rate for patients with intraepithelial, intramucosal and submucosal tumours was 92.8, 72.8 and 44.3 per cent respectively. The 5-year survival rate was higher after transthoracic than transhiatal oesophagectomy (66 versus 52 per cent). No survival advantage was observed after either operation in patients with mucosal tumours. Of 21 patients with recurrent disease, 20 had a submucosal lesion. The 5-year survival rate in patients with submucosal tumour was higher after transthoracic than transhiatal oesophagectomy (54.2 versus 25.5 per cent).

  9. Syntheses and study of pyrrolidinic nitroxide free radicals. Preparation of a nitroxide-type stable bi-radical; Synthese et etudes de radicaux libres nitroxydes pyrrolidiniques. Preparation d'un biradical stable du type nitroxyde

    Dupeyre, R.M. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires, Laboratoire de chimie organique physique


    Syntheses and study of pyrrolidinic nitroxide free radicals: These radicals are obtained by oxidation, with hydrogen peroxide, of pyrrolidinic amines prepared from triacetonamine by ring contraction. The U. V,, I. R, and E.P.R. spectral characteristics have been determined. The oxidation of these amines with hydrogen peroxide has led also to rupture of the pentagonal ring; some of the decomposition products have been identified. The high chemical stability of the nitroxide group has made it possible to synthesize and study a stable bi-radical. (author) [French] Syntheses et etudes de radicaux libres nitroxydes pyrrolidiniques: Ces radicaux sont obtenus par oxydation l'eau oxygenee d'amines pyrrolidiniques preparees a partir de la triacetonamine par contraction de cycle. Les caracteristiques spectroscopiques ultra-violettes, infra-rouge et resonance paramagnetique sont determinees. Cependant, 1'oxydation de ces amines a l'eau oxygenee a entraine la coupure du cycle pentagonal et identification de certaines substances de decomposition obtenues. La grande stabilite chimique de groupement nitroxyde a permis la synthese et l'etude d'un biradical stable. (auteur)

  10. Development of an analogue multiplexed regulation for periodic 1. order delayed processes; Etude et realisation d'une regulation analogique multiplexee pour processus aperiodiques du 1. ordre avec retard pur

    Amblard, J.C. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires


    The present note deals with the study regulations of the sampled type, for 1. order process with simple delay. In order to obtain a good stability in such regulations, together with acceptable performances, it is interesting to use polynomial type correctors acting directly on the sampled error signals. The active elements of these correctors can be shared by all the channels to be controlled. Furthermore, the determination of the correction parameters results from an optimal study of the system. In the second part is described the construction of a multiplexed regulation for diffusion ovens. (author) [French] La presente note concerne l'etude des regulations de type echantillonne, pour processus du 1. ordre avec retard pur. Pour obtenir une bonne stabilite de telles regulations, ainsi que des performances correcte il est interessant d'utiliser des correcteurs de type polynomial, agissant directement sur les signaux d'erreur echantillonnes. Les elements actifs de ces correcteurs peuvent etre pris communs a toutes les voies a controler. D'autre part, la determination des parametres de correction decoula d'une etude optimale du systeme. Dans une seconde partie on decrit la realisation d'une regulation multiplexee de fours a diffusion. (auteur)

  11. Radio-vulcanization of natural rubber in the latex phase. Study of an experimental 1 tonne per hour production; Radio-vulcanisation du caoutchouc naturel en phase latex. Etude d'une production experimentale de 1 tonne par heure

    Leveque, P.; Puig, J.R.; Roudeix, H. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    After briefly reviewing the main research carried out on the radio-vulcanization of latex and elastomers, a description is given of 4 types of cell which have been used successively with a view to industrial irradiation. They have made it possible to acquire the information necessary for resolving the main problem arising during irradiation - the formation of coagulum. The first two cell are designed for irradiation by a horizontal beam ('Dynamitron'), the two others use a vertical beam ('Circe'). The study of the properties of the rubber obtained shows it to compare favorably with 'Revultex'. In the appendix are given some characteristics of natural latex and information about its processing. (authors) [French] Apres un rappel des principales etudes sur la radio-vulcanisation du latex et des elastomeres, on decrit les quatre types de cellules successivement essayes en vue de l'irradiation industrielle. Ils ont permis d'acquerir les informations necessaires a la resolution du probleme principal pose par l'irradiation, la formation de coagulum au cours de celle,-ci. Les deux premiers sont concus pour l'irradiation par un faisceau horizontal ('Dynamitron'), les derniers par un faisceau vertical ('Circe'). L'etude des proprietes du caoutchouc obtenu montre qu'il se compare favorablement au 'Revultex'. Un apercu est donne en annexe des caracteristiques du latex naturel et de sa mise en oeuvre. (auteurs)

  12. Flica: a code for the thermodynamic study of a reactor or a test loop; Programme FLICA etude thermodynamique d'un reacteur ou d'une boucle d'essai

    Fajeau, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    This code handles the thermal problems of water loops or reactor cores under the following conditions: High or low pressure, steady state or transient behavior, one or two phases - Three-dimensional thermodynamic study of the flow in cylindrical geometry - Unidimensional study of heat transfer in heating elements - Neutronic studies can be coupled and a schematic representation of the safety rod behavior is given. The number of cells described in a flow cross-section is presently less than 20. This code is the logical following of FLID and CACTUS of which it constitutes a synthesis. (author) [French] Ce code permet de traiter les problemes thermiques d'une boucle ou d'un coeur de reacteur a eau dans les conditions suivantes: - Haute ou basse pression, regime permanent ou transitoire, simple ou double phase - Etude thermodynamique de l'ecoulement a 3 dimensions dans une geometrie cylindrique - Etude unidimensionnelle du transfert de chaleur dans les masses chauffantes - Possibilite de couplage avec la neutronique (reacteur point) et d'une representation schematique des actions de securite. Ce code dans lequel le nombre de cellules decrites dans une section droite de l'ecoulement est actuellement limite a 20 est la suite logique des codes FLID et CACTUS dont il constitue la synthese. (auteur)

  13. Applications of FLUKA Monte Carlo code for nuclear and accelerator physics

    Battistoni, Giuseppe; Brugger, Markus; Campanella, Mauro; Carboni, Massimo; Empl, Anton; Fasso, Alberto; Gadioli, Ettore; Cerutti, Francesco; Ferrari, Alfredo; Ferrari, Anna; Lantz, Matthias; Mairani, Andrea; Margiotta, M; Morone, Christina; Muraro, Silvia; Parodi, Katerina; Patera, Vincenzo; Pelliccioni, Maurizio; Pinsky, Lawrence; Ranft, Johannes; Roesler, Stefan; Rollet, Sofia; Sala, Paola R; Santana, Mario; Sarchiapone, Lucia; Sioli, Maximiliano; Smirnov, George; Sommerer, Florian; Theis, Christian; Trovati, Stefania; Villari, R; Vincke, Heinz; Vincke, Helmut; Vlachoudis, Vasilis; Vollaire, Joachim; Zapp, Neil


    FLUKA is a general purpose Monte Carlo code capable of handling all radiation components from thermal energies (for neutrons) or 1keV (for all other particles) to cosmic ray energies and can be applied in many different fields. Presently the code is maintained on Linux. The validity of the physical models implemented in FLUKA has been benchmarked against a variety of experimental data over a wide energy range, from accelerator data to cosmic ray showers in the Earth atmosphere. FLUKA is widely used for studies related both to basic research and to applications in particle accelerators, radiation protection and dosimetry, including the specific issue of radiation damage in space missions, radiobiology (including radiotherapy) and cosmic ray calculations. After a short description of the main features that make FLUKA valuable for these topics, the present paper summarizes some of the recent applications of the FLUKA Monte Carlo code in the nuclear as well high energy physics. In particular it addresses such top...

  14. E. P. R. spectroscopic study of nitroxide mono- and bi-radicals; Etude par spectroscopie de resonance paramagnetique electronique de monoradicaux et de biradicaux nitroxydes

    Lemaire, H. [Commissariat a l' Energie Atomique, Grenoble, 38 (France). Centre d' Etudes Nucleaires


    experimentales d'etude de produits parfaitement bien definis au point de vue structure chimique. L'etude par resonance paramagnetique electronique de monoradicaux nitroxydes conduit a la determination des axes et des elements du tenseur d'interaction hyperfine electron-noyau d'azote et du tenseur d'anisotropie du facteur de Lande: les resultats sont relies a la structure electronique des radicaux. On interprete qualitativement l'influence du solvant sur les elements des tenseurs, ainsi que les elargissements selectifs des raies hyperfines en milieu visqueux. Dans les biradicaux nitroxydes, la structure hyperfine depend non seulement des interactions magnetiques propres a chaque monomere, mais egalement de la grandeur de l'interaction d'echange separant les etats singulet et triplet du dimere; les biradicaux etudies ici sont les premiers composes organiques pour lesquels l'influence de l'echange sur la structure hyperfine est clairement mise en evidence. La presence de deux electrons non apparies introduit egalement une interaction magnetique dipolaire electron-electron, que l'on peut mettre a profit, dans le cas d'un echange intermediaire, pour determiner le signe de l'echange en etudiant le biradical dans un cristal liquide. Ces composes presentent egalement des elargissements selectifs de transitions hyperfines lorsque la viscosite du solvant croit. La theorie utilisee pour interpreter les largeurs de raie des monoradicaux est etendue au cas des biradicaux; elle rend compte des resultats experimentaux si l'on introduit simultanement les anisotropies des facteurs de Lande et des interactions dipolaires electrons-noyaux et electron-electron, en conduisant a une autre determination du signe de l'echange. (auteur)

  15. Observation of allotropic transformations of plutonium with a hot stage microscope; Etude des transformations allotropiques du plutonium au microscopic a platine chauffante

    Mars, J.; Spftiet, B. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires


    A hot stage microscope designed for the examination of plutonium and its alloys is described. This apparatus was used to study the {alpha} {r_reversible} {beta} and {delta} {r_reversible} {epsilon} allotropic transformations of pure or {beta} and {delta} stabilised plutonium. The {alpha} {yields} {beta} transformation is typically a nucleation and growth process. Some particularities caused by the internal stresses due to the volume change during this transformation are examined. The kinetics has been studied as a function of these stresses and a temperature dependent activation energy for nucleation has been deduced. The {beta} {yields} {alpha} transformation presents a memory effect which implies an orientation relationship between the two phases. This fact is probably caused by the stresses created during the {beta} {yields} {alpha} transition. The {beta} {r_reversible} {gamma} and {delta} {r_reversible} {epsilon} transformations are also diffusion governed processes. (authors) [French] On decrit un microscope a platine chauffante permettant l'examen du plutonium et de ses alliages. Cet appareil a servi a l'etude des transformations {alpha} {r_reversible} {gamma} et {delta} {r_reversible} {epsilon} du plutonium pur ou stabilise en phase {beta} et {delta}. La transformation {alpha} {yields} {beta} est une transformation typique par germination et croissance; elle presente des caracteristiques bien particulieres qui sont dues aux contraintes internes qui prennent naissance au changement de volume a la transformation; la cinetique a ete etudiee en fonction de ces contraintes, et on en a deduit une energie d'activation pour la germination variable avec la temperature. La transformation {beta} {yields} {alpha} presente un effet de memoire qui suppose une relation d'orientation entre les deux phases; ce phenomene semble lie comme auparavant aux contraintes creees par le passage {beta} {yields} {alpha}. Les transformations {beta} {r

  16. Some investigations on the pitting attack of magnesium and its alloys; Contribution a l'etude de la corrosion par piqures du magnesium et de ses alliages

    Blanchet, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    The pitting attack of magnesium and its alloys has been studied by means of potentio-kinetic polarisation curves; the following parameters have been considered: structural state and composition of the metal, chloride concentration and pH of the medium. The electrochemical data obtained demonstrate that when pH = 12, a localized corrosion might appear as soon as a 10{sup -3} M NaCl concentration is reached; on the other hand, when pH = 13, a much higher concentration (five times) has no effect. In the same conditions, the coupling of magnesium with various noble materials (graphite, platinum, 18/10 stainless steel) also dramatically increases its susceptibility to pitting, but only when chloride ions are present in the solution. Usual corrosion tests have confirmed these electrochemical results. A micrographic study of the pits has shown that their morphology is connected with the metallurgical state of the specimens. (author) [French] La corrosion par piqures du magnesium est etudiee a l'aide des courbes de polarisation potentiocinetiques en fonction des parametres suivants etat structural et composition du metal, concentration en chlorure et pH de la solution. De ces mesures electrochimiques on deduit qu'a pH 12, des la concentration 10{sup -3} M en NaCl, il existe un risque de corrosion localisee, tandis qu'a pH 13 une concentration cinq fois plus forte doit etre sans effet. Dans les memes conditions on montre que le couplage du magnesium avec differents elements nobles (graphite, platine, acier inoxydable 18/10) accroit fortement sa susceptibilite a l'attaque par piqures, excepte dans les solutions exemptes d'ions chlorures. Des essais classiques de corrosion dans les differentes solutions envisagees precedemment confirment les resultats de cette etude electrochimique. L'examen micrographique des piqures montre que leur morphologie est liee a l'etat metallurgique des echantillons. (auteur)

  17. Concerning the study of the irreversible magnetic behaviour of superconductivity; Contribution a l'etude du comportement magnetique irreversible des supraconducteurs

    Kuhn, G. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires


    The influence of the presence of extended lattice defects on the magnetic behaviour has been studied for the case of type I superconductors, such as Re and Ta, and in a more quantitative manner for the type II superconductor niobium. In this case, measurements of the thermal conductivity have given an estimate of the relative concentration of lattice defects in each specimen. These measurements show that the larger the number of lattice defects, the more irreversible becomes the magnetization curve, and the larger becomes the values of the critical current, which is related by a simple model to the magnetization values. Finally, a study by transmission electron microscopy has confirmed on the one hand the diversity of the extended lattice defects and on the other hand has allowed the formulation of several hypothesis on their respective influence. [French] L'influence de la presence de defauts etendus sur le comportement magnetique a ete etudie pour des supraconducteurs de premiere espece, tels que le rhenium et le tantale, et plus quantitativement pour un supraconducteur de deuxieme espece, le niobium. Dans ce cas, des mesures de conductibilite thermique ont permis d'estimer la concentration relative des defauts du reseau dans chaque echantillon. Ces mesures montrent que plus les defauts du reseau sont nombreux, plus la courbe d'aimantation est irreversible, et plus les valeurs du courant critique, reliees par un modele simple aux valeurs de l'aimantation, sont elevees. Enfin une etude par microscopie electronique en transmission - a permis d'une part de constater la diversite des defauts etendus et d'autre part de formuler quelques hypotheses sur leurs influences respectives.

  18. Contribution to the study of diffusion in poly-phase system; Contribution a l'etude de la diffusion en systeme polyphase

    Adda, Y.; Philibert, J. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires; Institut de Recherches de la Siderurgie Francaise (IRSID), 78 - Saint-Germain-en-Laye (France)


    this latter result and of the anomalies in the coefficient of diffusion should probably take into account the accumulation of reticular defects which would appear after displacement of the phase boundaries. (author) [French] Apres diffusion chimique entre deux metaux, a des temperatures auxquelles le diagramme d'equilibre indique l'existence de plusieurs phases, on observe, sur une section perpendiculaire au front de diffusion, des bandes paralleles correspondant a ces diverses phases. On sait que, dans ce cas, la courbe concentration-penetration presente alors une discontinuite a chaque interface. Les concentrations a l'aplomb de ces discontinuites donnent les limites de solubilites respectives des phases en presence. Au cours de nos essais relatifs au couple uranium-zirconium, nous avons verifie que ces concentrations ne varient pas avec la duree de diffusion et que, donc, les conditions de l'equilibre thermodynamique sont bien remplies. On dispose alors d'une methode interessante pour etablir le diagramme d'equilibre a l'etat solide, methode que nous avons appliquee au systeme U-Zr. Les etudes cinetiques de la diffusion polyphasee sont encore assez rares, par suite des difficultes experimentales. Aussi diverses methodes sont-elles proposees pour evaluer le coefficient de diffusion a partir d'etudes purement micrographiques (mesure des epaisseurs des phases intermediaires). Nos resultats experimentaux montrent que les hypotheses sur lesquelles sont basees ces methodes sont tres rarement valables. En effet, nous avons etabli les courbes concentration-penetration dans les systemes U-Zr (entre 590 deg. C et 950 deg. C), et U-MO (entre 800 deg. C et 1050 deg. C). Celles-ci montrent souvent des courbures tres accentuees, qui traduisent des variations du coefficient de diffusion qui ne peuvent pas s'exprimer suivant des relations simples. Enfin, nous avons observe certaines anomalies au voisinage des interfaces entre phases

  19. Study of gamma radiation between 0.1 and 1.0 MeV in the earth's atmosphere; Etude du rayonnement gamma entre 0,1 et 1 Mev dans l'atmosphere terrestre

    Boclet, D. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    The present work is devoted to some of the particular problems arising in the detection and localisation of sources of gamma radiation situated outside the earth's atmosphere. These weak sources can only be detected and localized if care is taken to eliminate gamma and particle radiations coming from other sources in the earth's atmosphere and in space. In order to separate the various sources of background noise, generally much stronger than the radiation under study, use is made of a directional detector whose characteristics are determined as described in the first part of the following report. The closest diffuse source considered is that constituted by the earth's atmosphere. Its detailed study will make it possible both to eliminate its effect when sources outside the earth are to be measured, and to predict the amount of secondary gamma radiation emitted by the same process in other celestial bodies, the moon in particular. This work considered in the 2. and 3. parts of the report. (author) [French] La presente etude est consacree a certains des problemes particuliers poses par la detection et la localisation des sources de rayonnement gamma situees hors de l'atmosphere terrestre. Ces sources faibles ne peuvent etre detectees et localisees que si l'on se protege des rayonnements gamma et particulaires provenant d'autres sources situees dans l'atmosphere terrestre et dans l'espace. Pour separer ces divers composants parasites, en general beaucoup plus intenses que le rayonnement a etudier, nous emploierons un detecteur directif dont nous determinons les caracteristiques dans la premiere partie de l'expose qui suit. La source diffuse la plus proche que nous considerons comme parasite est constituee par l'atmosphere terrestre. Son etude detaillee nous permettra d'une part de nous en proteger lorsque nous voudrons etudier les sources {gamma} extra-terrestres, d'autre part de prevoir le rayonnement gamma

  20. Application of radioactivity to subterranean hydraulic engineering (1961); Application de la radioactivite a l'hydraulique souterraine (1961)

    Hours, R. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    The search for radioactive tracers for water capable of percolating through permeable grounds without significant absorption has led to the choosing of two isotopes, bromine 82 (half-life 36 hours) and iodine (half-life 8 days), both {gamma} emitters; various combinations of other {gamma} emitters with longer half-lives have been tried but with only partial success. The recent progress in the dosage of tritium should make it possible to widen the field of application of this tracer which is unique in its kind. Being detectable at concentrations of 10{sup -6} to 10{sup -8} curies per cubic meter, the radioactive tracers are suitable for all the usual applications of conventional tracers; furthermore, some original techniques have been devised for measurements of flow, of reservoir capacity, of porosity and of permeability. Techniques based on the absorption and scattering of {gamma}-rays have also been developed for the measurement of the density, the humidity and the porosity of soils, and also for their analysis. Up to the present, radioactivity has been mainly applied to the study of oil-bearing formations. Furthermore, the study of the distribution of natural of thermonuclear tritium has contributed greatly to the study of the hydrological cycle. (author) [French] La recherche de traceurs radioactifs de l'eau susceptibles de circuler a travers les terrains permeables sans retention notable a abouti a la selection de deux isotopes, le brome 82 (periodes 36 heures) et l'iode (periode 8 jours), tous deux emetteurs {gamma}; diverses combinaisons mettant en jeu des emetteurs {gamma} de periode plus longue ont ete essayees, mais avec un succes partiel. Les progres recemment accomplis dans le dosage du tritium doivent permettre une rapide extension de l'emploi de ce traceur unique en son genre. Decelables a des concentrations de 10{sup -6} a 10{sup -8} curies par metre cube, les traceurs radioactifs se pretent a toutes les applications des traceurs

  1. Study of cis- and trans-uranium elements by paper chromatography and electrophoresis; Contribution a l'etude des elements cis- et trans-uraniens par chromatographie sur papier et electrophorese

    Clanet, F. [Commissariat a l' Energie Atomique, 92 - Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires


    In this work, the field of application of paper chromatography and electrophoresis in inorganic chemistry has been extended to elements 90 to 96 in hydrochloric and nitric acid solution. Results obtained concern the following points: 1) - Characterization of the valency states of Np and of Pu using coloured reactions on chromatograms and electrophoregrams. The valency IV is characterized by alizarin, arsenazo-I and thorin-I, whilst diphenylcarbazide is used for the hexavalent state. 2) - Paper chromatography: by using as eluent, mixtures of equal parts of aqueous HCl and HNO{sub 3} solutions and of alcohols (methanol, ethanol and n-butanol), the R{sub f} values of elements 90 to 96 have been determined. It has been possible to deduce certain conclusions concerning the complexing of these elements by Cl{sup -} and NO{sub 3}{sup -} ions. 3) - We have developed an electrophoretic technique on cellulose acetate membranes in order to separate the charged species formed by the elements 90 to 96 in HCl and HNO{sub 3} solutions from 1 to 12 M. Mobility curves have been obtained. It appears from our results that the tendency for the elements considered to form anionic complexes follows the order of the ionic potentials when the valency state is four; this order is reversed for the valency three. The ions Cl{sup -} have a smaller tendency to form complexes than the NO{sub 3}{sup -} ions with respect to these elements in their oxidation state III or IV, but the reverse phenomenon is observed for U{sup VI} and Pu{sup VI}. Finally, the complexing of the cations Pu{sup 4+} and PuUO{sub 2}{sup 2+} by NO{sub 3}{sup -} follows the order of the ionic potentials but occurs in the reverse order for Cl{sup -} ions. 4) - Various analytical applications are considered: separation of the various elements from each other and separation of the valency states of Np and of Pu. (author) [French] Dans cette etude, le champ d'application de la chromatographie sur papier et de l

  2. Chromosomes and irradiation: in vitro study of the action of X-rays on human lymphocytes; Chromosomes et radiations: etude in vitro de l'action des rayons X sur les lymphocytes humains

    Mouriquand, C.; Patet, J.; Gilly, C.; Wolff, C


    Radioinduced chromosomal aberrations were studied in vitro on leukocytes of human peripheral blood after x irradiation at 25, 50, 100, 200, and 300 R. The numeric and structural anomalies were examined on 600 karyotypes. The relationship between these disorders and the dose delivered to the blood are discussed. An explanation on their mechanism of formation is tentatively given. (authors) [French] L'etude in vitro des anomalies chromosomiques radioinduites a ete pratiquee sur des leucocytes de sang peripherique preleve chez 4 sujets et irradie aux doses de 25, 50, 100, 200, 300 R. Les aberrations numeriques et structurales ont ete examinees sur 600 caryotypes. Les rapports entre ces anomalies et les doses appliquees sont etudies. Une hypothese sur leur mecanisme de formation est avancee. (auteurs)

  3. Comparative Research on the Drum Music Playing Techniques of Etude and Gu Bian Dance Music%《练习曲》与《鼓边舞曲》鼓乐演奏技法比较研究



    文章描述了中国大堂鼓独奏曲《鼓边舞曲》的移植过程,并将其与原曲——俄罗斯小军鼓独奏作品《练习曲》进行比较,重点阐释了中西两种鼓乐器在乐曲演奏中的技法特色。%This paper described the process of adapting a Russia snare drum solo piece Etude to the Chinese Datang drum solo work Gu Bian Dance Music, and com-pared both of them, explained with the focus on the features playing techniques of Chinese and Western drum in the music.

  4. Contribution to the study of plasmatic fibrinogen and serum albumin: effects of irradiation; Contribution a l'etude du fibrinogene et de la serum-albumine plasmatiques - effets de l'irradiation

    Suscillon, M. [Commissariat a l' Energie Atomique, Centre d' Etudes Nucleaires de Grenoble, 38 (France)


    The author studies the modifications of properties and structure of serum albumin and fibrinogen solution when subjected to radiation of low energy (X rays). On the other hand, two original techniques are exposed: 1. Amperometric determination of fibrin stabilizing factor or factor XIII of hemostasis. 2. Spectrophotometric study of fibrin formation kinetics. Then showing off and quantitative determination of platelets fibrinogen is exposed. (author) [French] L'auteur etudie les modifications des proprietes et de la structure des molecules de serum-albumine et de fibrinogene en solution soumise a un flux de RX de basse energie. D'autre part deux techniques originales sont exposees : 1. Dosage amperometrique du facteur stabilisant de la fibrine. 2. Etude spectrophotometrique de la cinetique de la fibro-formation. Enfin une mise en evidence et un dosage du fibrinogene plaquettaire sont presentes. (auteur)


    LIU Mingshun; WU Xinman; HAN Ying; GU Langjie; LIU Qingrui


    Objectif: De explorer valeure appliquée de encéphale atlas dans évaluation de effet curatif de maladie cérébrovasculaire ischémique. Méthode: Etude comparative de encéphale atlas de 300 malades avec maladie cérébrovasculaire ischémique avant et après traitement est réalisé. Résultat:Encéphale atlas est changé manifestement avant et après traitement. Conclusion: Encéplale atlas est un index valable de jugement de effet curatif dans maladie cérébrovasculaire ischémique.

  6. Fullerenol - properties and applications in biomedical sciences

    Jacek Grębowski


    Full Text Available Fullerenols, the water-soluble derivatives of fullerenes, are currently being recently intensively studied in the context of the possibility of their application in the biomedicine. Due to their hydrophilic properties and the ability to eliminate free radicals, fullerenols may in the future provide a solid alternative to currently used pharmacological methods in chemotherapy, treatment of neurodegenerative diseases and radiobiology. Depending on the research protocol applied, fullerenols may also act as pro oxidants. The dualistic nature of fullerenols may contribute to finding new biomedical applications of these agents in the future, by exerting a cytotoxic or protective effect respectively against cancer cells or healthy cells. Because of the encapsulated structure of fullerenols, there exists the possibility of their application in medical diagnostics in the transfer of contrast agents or in the drug transport. During the planning of an experiment designed to investigate the effects of radiation in combination with derivatives of water-soluble fullerenes, the possibility of appearance of the “dose-response effect” should be taken into consideration since it significantly contributes to one of the two possible effects: protection or sensitization. The same applies to the possibility of using these compounds as potential neuroprotectors. Fullerenol may protect neurons in the particular areas of the brain but in the definedcertain doses it may also induce cell death. A giant leap in the field of nanotechnology not only leads scientists to search for new applications of nanomaterials such as fullerenols, but also raises the question about their harmful effect on the environment. High utilization of hardly biodegradable fullerenols increases the likelihood of their accidental release into natural systems and their bioaccumulation. Despite convincing evidences about the potential applications of fullerenols in biomedicine, we still have

  7. Contribution to the study of {beta} disintegration and of nuclear structure using experiments on certain {beta}-{gamma} cascades: 198{sub Au}, 86{sub Rb}, 170{sub Tm}; Contribution a l'etude de la desintegration beta et a l'etude de la structure nucleaire a l'aide d'experiences sur certaines cascades beta-gamma: 198{sub Au}, 86{sub Rb}, 170{sub Tm}

    Lachkar, J. [Commissariat a l' Energie Atomique, Bruyeres-le-Chatel (France). Centre d' Etudes; Paris-11 Univ., fabulte des Sciences 91 - Orsay (France)


    {beta}{gamma} directional angular correlations and shapes of inner beta spectra leading to the first excited level of the final nucleus enable one to determine the nuclear matrix elements typical of the {beta} transition. In the three observed first forbidden cases: {sup 170}Tm, {sup 86}Rb, {sup 198}Au, these matrix elements do not confirm the independent shell model theory. Other hypotheses are then suggested and discussed. (author) [French] Les experiences de correlation angulaire {beta}{gamma} et l'etude du spectre {beta} conduisant au premier niveau excite du noyau final permettent de determiner les elements de matrices nucleaires caracteristiques de cette transition. Dans les trois cas etudies (transitions une fois interdites): {sup 170}Tm, {sup 86}Rb, {sup 198}Au, ces elements de matrices ne peuvent etre retrouves a l'aide du modele en couches et a particules independantes. D'autres hypotheses sont alors emises et discutees. (auteur)

  8. Study of various processes for marking sediments with gold-198; Etude de divers procedes de marquages de sediments par l'or 198

    Jeanneau, B. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    The use of radioactive isotopes for the study of sediment deposits is based mainly on two methods: marking in the mass - a glass of an element which can be activated replaces the sediment; surface marking - a physico-chemical process is used to deposit a radio-element at the surface of the sediment. The second process is used in particular for sands when it is advantageous to have a large number of particles for statistical analysis. The aim of this work was to develop a rapid and simple method of marking which could be applied on the actual site of the experiment where equipment, may be limited. The method recommended for marking sand with gold-198 is a combination of the Petersen (treatment with tin chloride) and Campbell (treatment with silver) methods combined with prior treatments with nitric acid and caustic soda. Using this method it is possible to deposit 125 mg of gold per kilo of sediment with a yield of 95 per cent (i.e. 10 Ci/kg) using a hydrochloric acid solution containing gold. The problem of the solidity of the deposits, of their value and of their reproducibility is discussed from the point of view of the mineral constitution of the sand. (author) [French] L'utilisation d'isotopes radioactifs pour l'etude des deplacements sedimentaires fait, principalement appel a deux methodes: le marquage massique - un verre contenant un element activable remplace le sediment; le marquage superficiel - un traitement physico-chimique permet de deposer un radioelement a la surface du sediment. Le second procede est surtout employe pour les sables lorsqu'il est utile de disposer d'un grand nombre de grains pour des raisons statistiques. Le but de ce travail etait de mettre au point une methode simple et rapide de marquage pouvant etre appliquee sur le site meme de l'experience pour les utilisateurs disposant d'un equipement limite. Le procede preconise pour le marquage des sables par l'or 198 est une combinaison des methodes

  9. Preliminary studies leading to a conceptual design of a 1000 MWe fast neutron reactor; Etudes preliminaires conduisant a un concept de reacteur a neutrons rapides de 1000 MWe

    Vendryes, G.; Zaleski, C.P. [Association Euratom-CEA Cadarache (France). Centre d' Etudes Nucleaires


    This report presents the results of studies which seemed important to undertake in connexion with the development of fast neutron reactors. - It points out the advantage of high internal breeding ratios ({approx}1, 1) which are necessary in order to get a small change in time both in power distribution and reactivity (less: than 0.005 {delta}k/k in 18 months). - It shows how to achieve this goal, when simultaneously power distribution flattening is obtained. These results in a higher mean specific power (which is an economic gain) and therefore in a smaller doubling time (about 10 years). - It attempts to find criteria concerning the specific power that should be used in future reactor designs -It presents a conceptional design of a 1000 MWe fast neutron reactor, for the realisation of which no technological impossibility appears. - It shows that the dynamic behaviour seems satisfactory despite a positive total isothermal sodium coefficient. - It tries to predict the development of fast reactors within the future total nuclear program. It does not appear that fissile materials supply problems should in France slow down the development of fast neutron reactors, which will be essentially tied up to its economical ability to produce cheap electric power. (authors) [French] Ce rapport presente les etudes qu'il nous a paru important d'aborder dans le cadre du developpement des reacteurs a neutrons rapides. - Il met en evidence l'interet des taux de regeneration internes eleves ({approx}1, 1) pour obtenir une bonne evolution dans le temps de la distribution de puissance et de la reactivite (moins de 0,005 {delta}k/k pour 18 mois). - Il montre la possibilite d'y parvenir tout en applatissant la distribution des fissions, ce qui se traduit par une puissance specifique moyenne plus elevee (gain economique), et donc un temps de doublement plus faible de l'ordte de 10 ans - Il tente de definir un optimum de la puissance specifique valable pour les

  10. Study of fast neutron scattering. The displacement cross-section (1962); Etude de la diffusion des neutrons rapides. Section efficace de deplacement (1962)

    Millot, J.P. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires


    We propose a method for calculating the biological efficiency of fast neutrons emitted by in-pile fission sources. This method justifies the empirical theory of Albert and Welton. In making simple assumptions concerning the cross-sections, we have supposed that the propagation can ben reduced to a mono-kinetic problem. A system of orthonormal functions is then set up making it possible to calculate the flux leaving a planar source. This method generalises the results obtained by Platzek to the case where the elastic cross-sections are not isotropic, and make it possible in particular to define a displacement cross-section: extension of the diffusion coefficient. This method can be generalised to the case of neutron diffraction as a function of time, and to the study of slowing-down. Numerical results are given in an appendix for the following: H{sub 2}O, D{sub 2}O, Fe, Be, Pb, CH, CH{sub 2}. These cross-sections have been verified experimentally in water and in graphite for neutrons of 2.5 and 14 MeV using a SAMES accelerator and a 2 MeV Van De Graaff. (author) [French] Nous proposons une methode permettant de calculer l'efficacite biologique des neutrons rapides issus des sources de fission dans la protection d'une pile. Cette methode justifie la theorie empirique d'Albert et Welton. En faisant des hypotheses simples sur les sections efficaces, nous avons suppose que la propagation pouvait etre ramenee a un probleme monocinetique. Nous construisons alors un systeme de fonctions orthonormales qui permet de calculer le flux issu d'une source plane. Cette methode generalise les resultats obtenus par Platzek au cas ou les sections efficaces elastiques ne sont pas isotropes et en particulier permet de definir une section efficace de deplacement: extension du coefficient de diffusion. Cette methode peut etre generalisee a la diffusion des neutrons en fonction du temps et a l'etude du ralentissement. Les resultats numeriques sont donnes en annexe

  11. Gestion des ressources hydriques adaptee aux changements climatiques pour la production optimale d'hydroelectricite. Etude de cas: Bassin versant de la riviere Manicouagan

    Haguma, Didier

    Il est dorenavant etabli que les changements climatiques auront des repercussions sur les ressources en eau. La situation est preoccupante pour le secteur de production d'energie hydroelectrique, car l'eau constitue le moteur pour generer cette forme d'energie. Il sera important d'adapter les regles de gestion et/ou les installations des systemes hydriques, afin de minimiser les impacts negatifs et/ou pour capitaliser sur les retombees positives que les changements climatiques pourront apporter. Les travaux de la presente recherche s'interessent au developpement d'une methode de gestion des systemes hydriques qui tient compte des projections climatiques pour mieux anticiper les impacts de l'evolution du climat sur la production d'hydroelectricite et d'etablir des strategies d'adaptation aux changements climatiques. Le domaine d'etude est le bassin versant de la riviere Manicouagan situe dans la partie centrale du Quebec. Une nouvelle approche d'optimisation des ressources hydriques dans le contexte des changements climatiques est proposee. L'approche traite le probleme de la saisonnalite et de la non-stationnarite du climat d'une maniere explicite pour representer l'incertitude rattachee a un ensemble des projections climatiques. Cette approche permet d'integrer les projections climatiques dans le probleme d'optimisation des ressources en eau pour une gestion a long terme des systemes hydriques et de developper des strategies d'adaptation de ces systemes aux changements climatiques. Les resultats montrent que les impacts des changements climatiques sur le regime hydrologique du bassin de la riviere Manicouagan seraient le devancement et l'attenuation de la crue printaniere et l'augmentation du volume annuel d'apports. L'adaptation des regles de gestion du systeme hydrique engendrerait une hausse de la production hydroelectrique. Neanmoins, une perte de la performance des installations existantes du systeme hydrique serait observee a cause de l'augmentation des

  12. Modelisation Des Effets De la Rugosite Sur L'Etude De L'Humidite Des Sols Par Radiometrie Micro-Ondes. Application a la Mission Spatiale Smos

    Demontoux, François; Wigneron, Jean Pierre


    As part of the SMOS mission (Soil Moisture and Ocean Salinity) IMS and EPHYSE laboratories are involved in the study and validation of the inversion algorithm LMEB. In the framework of this study, we developed a model using the numerical modeling software-HFSS ANSOFT. It allows the computation of the emissivity of multilayer systems (soil-litter for example). We have improved our approach to incorporate new parameters that can have a significant effect on the measurements. Indeed, so far the effect of soil roughness associated with the litter has not been studied. Moreover, the thickness of litter is never constant and we must therefore introduce a realistic profile of litter thickness. This article presents our work to integrate these profiles in our numerical model. These profiles may be derived from measurements (litter thickness profiles or soil roughness profiles) or calculations (roughness profile). In both cases the input data of our model are files of XYZ points representing our profile.

  13. Etude structurale et optique de la précipitation des ions de terres-rares et des nanoparticules de silicium dans la silice pour des applications optiques

    Beainy, Georges


    As a material of choice in the modern microelectronics, silicon has attracted increasingattention in the last decade with the aim to integrate both optoelectronic and microelectronicfunctionalities on a same silicon chip. Due to its physical properties, bulk silicon is a poorlight emitter. The development of an efficient silicon based light emitter is therefore achallenging issue. Rare earth ions incorporated silicon nanoparticles in silica thin films haveemerged as promising route to obtain ...

  14. Discotic liquid crystal thin films: properties and photovoltaic application; Etude des proprietes de films minces de cristaux liquides discotiques pour la conversion photovoltaique organique

    Archambeau, S.


    Organic material based photovoltaic cells are under study since a long time but their power efficiency still remains poor. As a consequence of their excellent transport properties, organic discotic materials were used in this work to fabricate low cost solar cell devices. The objective as a matter of fact was to increase the mobility within our thin films by thermal annealing in order to organize the molecules in the form of columns. These annealing led to a de-wetting resulting in an appreciable inhomogeneity in film thickness and appearance of short-circuits during the realization of the cells. In order to avoid these de-wetting different solutions (impregnation, electro-wetting and ITO treatments) were studied. Then, we demonstrated the exciton diffusion length increasing when molecules are in the columnar organization. (author)

  15. Etude d'un problème d'interaction fluide-structure : Application au flux artériel.

    Giudicelli, Bernard


    Fluid structure interaction problems are more and more used in the industry and in many research field. The medical imagery evolution leads to new biomecanical problems. One of them is the study of the blood flow in arteries. There is two kinds of fluid structure interaction problem in the blood flow study. The first one is the the evolution of the blood cells in the plasma. The second one is the intercation between the fluid and the artery wall, this problem is the topic of this thesis.In ou...

  16. Etude paramétrique avancée de canaux SISO et MIMO en environnements complexes : Application au système HiperLAN/2

    Chartois, Yannick


    Wireless mobile telecommunications have known a growing interest formore than one decade. They break up into two types of use:telephony and wireless networks. The complementarity of thesetwo technologies offers an enormous potential to provide the usersa mobility without interruption of service when the user passes fromthe public property to private property and reciprocally. However, whatever the wireless communication system considered, itis subjected to a strong constraint due to the multi...

  17. Etude pour quantifier la part des apports internes dans bâtiment tertiaire BBC. Application au bâtiment de PREDIS

    Chenailler, Hervé; Wurtz, Frédéric; Ploix, Stéphane; Joussellin, Florence; Bontemps, André


    National audience; La conception de bâtiments a longtemps été réduite à la conception de leurs enveloppes, reléguant ainsi la représentation des usages à des courbes d'apports internes gratuits. Or, la recherche de meilleures performances en termes d'efficacité énergétique, qui se traduit par le rapport entre les besoins en énergie non gratuite sur le confort pour les occupants, pose le problème de conception en des termes nouveaux. Il s'agit dès lors de vérifier que l'énergie consommée corre...

  18. Contribution a l'etude des mecanismes de l'adhesion de la glace a differents materiaux et application a l'evaluation des materiaux glaciophobes

    Ghalmi, Zahira

    Several Nordic countries with cold climates like Canada are often subjected to ice storms causing major economic and social losses. Ice or sticky snow adhesion on power network equipment can be a significant issue in transmission and distribution of electrical energy for companies operating in these regions. The costs of such events can be substantial, particularly due to the cessation of economic activities, equipment failures, deicing techniques (active methods), and population safety. Because of such events, power companies have understood the need to develop so-called superhydrophobic and/or icephobic surfaces, which can significantly reduce ice adhesion (passive methods). Several studies have led to the development of a variety of new nanostructured surfaces using various strategies. These studies have led to the design of superhydrophobic surfaces with contact angles greater than 150 and low ice adhesion strength. In order to optimally reduce the ice adhesion strength on different substrates, better understanding of the various mechanisms involved in the icing process is essential. It is in this context and within the framework of Canada's research chair on atmospheric icing of power networks (INGIVRE) that this thesis was carried out, aiming to improve the knowledge of atmospheric icing, and explain the forces involved at the ice/substrate interface. Furthermore, the effect of contact angle, surface roughness and porosity on icing and ice/substrate interface was investigated. This study clearly showed that the electrostatic, van der Waals and hydrogen bond forces are the main contributors to ice adhesion to a surface at the molecular level. The electrostatic energy, based on the principle of image charge, depends on the type of material in contact with the ice, the distance between the ice and the material, and the types of ice surface defects. The van der Waals energy depends on the material type, the thickness of the liquid water layer, and the temperature. For its part, the energy associated with hydrogen bonds depends on the material type, temperature, droplet mass, as well as on the static and sliding contact angles. Among these three forces, the electrostatic energy is the largest. Whereas the hydrogen bond energy is larger than the van der Waals energy. However, the latter is always present as long as ice is in contact with a solid surface. The experimental study showed that ice adhesion strength depends on the surface roughness of the substrate. In the case of metals with a thin natural protective oxide layer, higher roughness leads to higher ice adhesion strength. In other words, polished metallic surfaces exhibit lower ice adhesion strengths. However, in the case of anodized aluminum surfaces coated with PTFE, the roughened needle-like structure resulted in lower ice adhesion. The experimental results showed that PTFE coatings remain resistant to icing/deicing cycles. Even after 15 icing/deicing cycles, surfaces remain hydrophobic with a static contact angle greater than 130°.

  19. Etude mathématique et numérique de modèles de transport : application à la spintronique

    El Hajj, Raymond


    This thesis is decomposed into three parts. The main part is devoted to the study of spin polarized currents in semiconductor materials. An hierarchy of microscopic and macroscopic models are derived and analyzed. These models take into account the spin relaxation and precession mechanisms acting on the spin dynamics in semiconductors. We have essentially two mechanisms : the spin-orbit coupling and the spin-flip interactions. We begin by presenting a semiclassical analysis (via the Wigner tr...

  20. Statistical signal processing for gamma spectrometry: application for a pileup correction method; Traitement statistique du signal spectrometrique: etude du desempilement de spectre en energie pour la spectrometrie gamma

    Trigano, T


    The main objective of gamma spectrometry is to characterize the radioactive elements of an unknown source by studying the energy of the emitted photons. When a photon interacts with a detector, its energy is converted into an electrical pulse. The histogram obtained by collecting the energies can be used to identify radioactive elements and measure their activity. However, at high counting rates, perturbations which are due to the stochastic aspect of the temporal signal can cripple the identification of the radioactive elements. More specifically, since the detector has a finite resolution, close arrival times of photons which can be modeled as an homogeneous Poisson process cause pile-ups of individual pulses. This phenomenon distorts energy spectra by introducing multiple fake spikes and prolonging artificially the Compton continuum, which can mask spikes of low intensity. The objective of this thesis is to correct the distortion caused by the pile-up phenomenon in the energy spectra. Since the shape of photonic pulses depends on many physical parameters, we consider this problem in a nonparametric framework. By introducing an adapted model based on two marked point processes, we establish a nonlinear relation between the probability measure associated to the observations and the probability density function we wish to estimate. This relation is derived both for continuous and for discrete time signals, and therefore can be used on a large set of detectors and from an analog or digital point of view. It also provides a framework to this problem, which can be considered as a problem of nonlinear density deconvolution and nonparametric density estimation from indirect measurements. Using these considerations, we propose an estimator obtained by direct inversion. We show that this estimator is consistent and almost achieves the usual rate of convergence obtained in classical nonparametric density estimation in the L{sup 2} sense. We have applied our method to a set of experimental data and we have shown that the distortions caused by the pile-up phenomenon are well corrected by the algorithms derived from our estimators. (author)

  1. Les activités de conservation des lémuriens par le Groupe d’Etude et de Recherche sur les Primates de Madagascar (GERP Conservation activities of lemurs by the Madagascar Primate Research Group (GERP- Groupe d’Etude et de Recherche sur les Primates de Madagascar

    Rose Marie Randrianarison


    Full Text Available Le Groupe d’Etude et de Recherche sur les Primates de Madagascar, une association de conservation, a été créée en 1994 grâce à l’initiative des Enseignants Chercheurs et étudiants du Département de Paléontologie et d’Anthropologie Biologique et du Département de Biologie Animale de l’Université d’Antananarivo. Le GERP regroupe actuellement des membres scientifiques multidisciplinaires Malgaches et étrangers dont la majorité d’entre eux est constituée par des primatologues. Les principales actions du GERP se focalisent sur les travaux de recherche sur les Primates Prosimiens de Madagascar, l’établissement de leur plan de conservation, la découverte de nouvelles espèces de lémuriens, la translocation et le transfert des lémuriens vivant dans des milieux défrichés ou précaires, le suivi et l’abondance des lémuriens ainsi que la révision de leurs aires de distribution. Les résultats des recherches effectuées sur la conservation ont permis de publier des articles dans des revues de renommée nationale et internationale sur la Primatologie. En outre, le renforcement de capacité et l’éducation de la communauté de base, des systèmes éducatifs primaires et supérieurs sur la conservation des lémuriens et l’appui aux activités de développement durable de la population locale s’avèrent nécessaires pour que la conservation des lémuriens soit pérenne.The Madagascar Primate Research Group (GERP - Groupe d’Etude et de Recherche sur les Primates de Madagascar is a conservation-focused association created in 1994 by the initiative of researcher lecturers and students from the Department of Paleontology and Biological Anthropology and the Department of Animal Biology of the University of Antananarivo. The GERP membership consists of multidisciplinary scientists, both Malagasy and foreign, the majority of whom are primatologists. The principle actions of the association are focused on research on the

  2. Etude du processus de changement vecu par des familles ayant decide d'adopter volontairement des comportements d'attenuation des changements climatiques

    Leger, Michel T.

    recension des ecrits sur le changement de comportement en environnement. Nous explorons egalement la famille comme systeme fonctionnel de sorte a mieux comprendre ce contexte d'action environnementale qui est, a notre connaissance, peu etudie. Dans le deuxieme article, nous presentons nos resultats de recherche concernant les facteurs d'influence observes ainsi que les competences manifestees au cours du processus d'adoption de nouveaux comportements environnementaux dans trois familles. Enfin, le troisieme article presente les resultats du cas d'une quatrieme famille ou les membres vivent depuis longtemps des modes de vie ecologique. Dans le cadre d'une demarche d'analyse par theorisation ancree, l'etude de ce cas modele nous a permis d'approfondir les categories conceptuelles identifiees dans le deuxieme article de sorte a produire une modelisation de l'integration de comportements environnementaux dans le contexte de la famille. Les conclusions degagees grace a la recension des ecrits nous ont permis d'identifier les elements qui pourraient influencer l'adoption de comportements environnementaux dans des familles. La recension a aussi permis une meilleure comprehension des divers facteurs qui peuvent affecter l'adoption de comportements environnementaux et, enfin, elle a permis de mieux cerner le phenomene de changement de comportement dans le contexte de la famille consideree comme un systeme. En appliquant un processus d'analyse inductif, a partir de nos donnees qualitatives, les resultats de notre etude multi-cas nous ont indique que deux construits conceptuels semblent influencer l'adoption de comportements environnementaux en famille : 1) les valeurs biospheriques communes au sein de la famille et 2) les competences collectivement mises a profit collectivement durant l'essai de nouveaux comportements environnementaux. Notre modelisation du processus de changement dans des familles indique aussi qu'une dynamique familiale collaborative et la presence d'un groupe de

  3. Survey of Hyperspectral and Multispectral Imaging Technologies (Etude sur les technologies d’imagerie hyperspectrale et multispectrale)


    Prism-Grating-Prism Imaging Spectrograph 3-4 Figure 5 Basic Principle of the IMSS 3-5 Figure 6 Optical Scheme of Sagnac and Michelson Imaging...the dispersive techniques in imaging spectrometers applications is the Image Multi- Spectral Sensing ( IMSS ) technology, developed and patented by...Pacific Advanced Technology since 1992.The IMSS is based on the principle of diffractive optics; as such it is a combination of a diffractive imaging

  4. Facilities for external radiation accessible for investigation on biological studies - progress report may 2004; Les installations d'irradiation externe accessibles aux etudes de biologie - etat d'avancement mai 2004

    Gaillard-Lecanu, E. [CEA Fontenay aux Roses (DSV/Carmin), 92 (France); Authier, N.; Verrey, B. [CEA Valduc, Dept. Recherche sur les Materiaux Nucleaires, 21 - Is-sur-Tille (France); Bailly, I. [CEA Bruyeres le Chatel, 91 (France). Dept. de Physique Theorique et Appliquee; Baldacchino, G.; Pin, S.; Pommeret, S.; Renault, J.Ph. [CEA Saclay, Dept. de Recherche sur Etat Condense, les Atomes et les Molecules, 91 - Gif sur Yvette (France); Bordy, J.M. [CEA Saclay, Dir. de la Recherche Technologique (DRT/DETECS/LNHB/LMD), 91 - Gif sur Yvette (France); Coffigny, H. [CEA Fontenay aux Roses, Dept. de Radiobiologie et de Radiopathologie, 92 (France); Cortela, L. [CEA Grenoble, ARC-Nucleart, 38 (France); Duval, D. [CEA Saclay, Schering - CIS bio International, 91 - Gif sur Yvette (France); Leplat, J.J. [CEA Saclay (DSV/DRR/LREG), 91 - Gif sur Yvette (France); Poncy, J.L. [CEA Fontenay aux Roses (DSV/DRR/SRCA), 92 (France); Testard, I. [CEA Caen (DSV/DRR/LRO-LARIA), 14 - Caen (France); Thuret, J.Y. [CEA Saclay (DSV/DBJC/SBGM), 91 - Gif sur Yvette (France)


    The Life Science Division of the Atomic Energy Commission is making an inventory of the various radiation sources accessible for investigation on the biological effects of ionizing radiation. In this field, a wide range of studies is being carried out at the Life Science Division, attempting to characterize the kind of lesions with their early biological consequences (on the various cell compartments) and their late biological consequences (deterministic or stochastic effects), in relation to the radiation type and dose, especially at low doses. Several experimental models are available: plants, bacteria, eukaryotic cells from yeast up to mammalian cells and in vivo studies, mostly on rodents, in order to characterize the somatic late effects and the hereditary effects. Due to the significant cost of these facilities, also to their specific properties (nature of the radiation, dose and dose rate, possible accuracy of the irradiation at the molecular level), the closeness is no longer the only criteria for biologists to make a choice. The current evolution is to set up irradiation infrastructures combining ionizing radiation sources themselves and specific tools dedicated to biological studies: cell or molecular biology laboratories, animal facilities. The purpose, in this new frame, is to provide biologists with the most suitable facilities, and, if possible, to change these facilities according to requirements in radiobiology. In this report, the basics of interactions of ionizing radiation with biological tissues are briefly introduced, followed by a presentation of some of the facilities available at the CEA for radiobiological studies. This panorama is not a comprehensive one, new data will be included as they advance, whether reporting existing facilities or if a new one is developed. (authors)

  5. External irradiation facilities open for biological studies - progress in july 2005; Les installations d'irradiation externe accessibles aux etudes de biologie etat d'avancement juillet 2005

    Gaillard-Lecanu, E. [CEA Fontenay aux Roses (DSV/Carmin), 92 (France); Authier, N.; Verrey, B. [CEA Valduc, Dept. Recherche sur les Materiaux Nucleaires, 21 - Is-sur-Tille (France); Bailly, I. [CEA Bruyeres le Chatel, 91 (France). Dept. de Physique Theorique et Appliquee; Baldacchino, G.; Pin, S.; Pommeret, S.; Renault, J.Ph. [CEA Saclay, Dept. de Recherche sur Etat Condense, les Atomes et les Molecules, 91 - Gif sur Yvette (France); Bordy, J.M. [CEA Saclay, Dir. de la Recherche Technologique (DRT/DETECS/LNHB/LMD), 91 - Gif sur Yvette (France); Coffigny, H. [CEA Fontenay aux Roses, Dept. de Radiobiologie et de Radiopathologie, 92 (France); Cortela, L. [CEA Grenoble, ARC-Nucleart, 38 (France); Duval, D. [CEA Saclay, Schering - CIS bio International, 91 - Gif sur Yvette (France); Leplat, J.J. [CEA Saclay (DSV/DRR/LREG), 91 - Gif sur Yvette (France); Poncy, J.L. [CEA Fontenay aux Roses (DSV/DRR/SRCA), 92 (France); Testard, I. [CEA Caen (DSV/DRR/LRO-LARIA), 14 - Caen (France); Thuret, J.Y. [CEA Saclay (DSV/DBJC/SBGM), 91 - Gif sur Yvette (France)


    The Life Science Division of the Atomic Energy Commission is making an inventory of the various radiation sources accessible for investigation on the biological effects of ionizing radiation. In this field, a wide range of studies is being carried out at the Life Science Division, attempting to characterize the kind of lesions with their early biological consequences (on the various cell compartments) and their late biological consequences (deterministic or stochastic effects), in relation to the radiation type and dose, especially at low doses. Several experimental models are available: plants, bacteria, eukaryotic cells from yeast up to mammalian cells and in vivo studies, mostly on rodents, in order to characterize the somatic late effects and the hereditary effects. Due to the significant cost of these facilities, also to their specific properties (nature of the radiation, dose and dose rate, possible accuracy of the irradiation at the molecular level), the closeness is no longer the only criteria for biologists to make a choice. The current evolution is to set up irradiation infrastructures combining ionizing radiation sources themselves and specific tools dedicated to biological studies: cell or molecular biology laboratories, animal facilities. The purpose, in this new frame, is to provide biologists with the most suitable facilities, and, if possible, to change these facilities according to requirements in radiobiology. In this report, the basics of interactions of ionizing radiation with biological tissues are briefly introduced, followed by a presentation of some of the facilities available for radiobiological studies especially at CEA. This panorama is not a comprehensive one, new data will be included as they advance, whether reporting existing facilities or if a new one is developed. (authors)


    V. A. Kashparov


    Full Text Available The present radiological situation in the agricultural production of Ukraine is considered and analyzed. On the basis of optimization of the countermeasures application the approaches are proposed which would guarantee the compliance of the agricultural production with the corresponding State hygienic regulations, as well as reduction of the effective exposure dose to population below the approved limits. Taking into account the lately growing interest to radiation protection of not only human, but the environment as well, the results of the studies of frequency of the radiobiological effects of chronic irradiation to plantations of Scots pine in the Chernobyl exclusion zone depending on the levels of the dose to the trees' apical meristem are presented.

  7. Etude D’un Test D’Exsudation Du Trinitrotoluene (Study of an Exudation Test of Trinitrotolvene),


    as a TNT production control test was studied. Known impurities were introduced into rNT to determine the limits of application of the test. It is...procEdure. (NC) ABSTRACT An exudation test that could be used as a TNT production control test was studied. Known impurities were introduced into TNT to...filtres Mhatman ont 6t6 manufactur6s par W R Baiston Ltd., de ILondres. 2.4 Chromatographic liquido i haute performance Los analyses do L)NT dans le

  8. Study of hazardous scenario in service stations. Final report; Etude de scenarios dangereux en stations-service. Rapport final



    The industrial environment group is working at the elaboration of prescriptions applicable to classed installations submitted to declaration (heading 1434: fill in and distribution of inflammable liquids). In this context the group asked the INERIS to realize a list of possible accidents scenario, to quantify the consequences in terms of safety distances, to identify the most pertinent scenario and to examine the particular cases which allow to reduce the safety distances especially the implementing of a fire break wall of two hours. (A.L.B.)

  9. Survey of radiation protection programmes for transport; Etude des programmes de radioprotection pour les transports de matieres radioactives

    Lizot, M.T.; Perrin, M.L.; Sert, G. [CEA Fontenay-aux-Roses, Inst. de Protection et de Surete Nucleaire, Dept. de Protection et de Surete Nucleaire, 92 (France); Lange, F.; Schwarz, G.; Feet, H.J.; Christ, R. [Gesellschaft fur Anlagen-und Reaktorsicherheit, GRS, mbH, Cologne (Germany); Shaw, K.B.; Hughes, J.S.; Gelder, R. [National Radiological Protection Board (NRPB), Oxon, OX (United Kingdom)


    The survey of radiation protection programmes for transport has been jointly performed by three scientific organisations I.P.S.N. (France), G.R.S. ( Germany), and N.R.P.B. (United kingdom) on behalf of the European Commission and the pertaining documentation summarises the findings and conclusions of the work that was undertaken with the principal objectives to provide guidance on the establishment, implementation and application of radiation protection programmes for the transport of radioactive materials by operators and the assessment and evaluation of such programmes by the competent authority and to review currently existing radiation protection programmes for the transport of radioactive materials. (N.C.)

  10. Alg\\`ebres amass\\'ees et applications

    Keller, Bernhard


    Sergey Fomin and Andrei Zelevinsky have invented cluster algebras at the beginning of this decade with the aim of creating an algebraic framework for the study of canonical bases in quantum groups and total positivity in algebraic groups. It soon turned out that the combinatorics of cluster algebras also appear in many other subjects and notably in the representation theory of quivers and finite-dimensional algebras. In this talk, we give a concise introduction to cluster algebras and sketch two significant applications concerning the study of certain discrete dynamical systems and the construction of dual semicanonical bases. ----- Sergey Fomin et Andrei Zelevinsky ont invent\\'e les alg\\`ebres amass\\'ees (cluster algebras) au d\\'ebut des ann\\'ees 2000 dans le but de fournir un cadre alg\\'ebrique \\`a l'\\'etude des bases canoniques dans les groupes quantiques et de la positivit\\'e totale dans les groupes alg\\'ebriques. Il s'est av\\'er\\'e rapidement que la combinatoire des alg\\`ebres amass\\'ees intervenait \\'eg...

  11. Etude de la Production des Mesons d* Sur le PIC de Resonance du Boson Z Observes AU Lep avec le Detecteur Opal

    Przysiezniak, Helenka

    L'etude de la production des mesons D* est effectuee a partir d'evenements multihadroniques rm Z^0to q| q, avec des donnees prises en 1990, 1991 et 1992 avec le detecteur OPAL au LEP. La notation q definit les quarks des cinq saveurs pouvant etre observees au LEP: up (u), down (d), strange (s), charme (c), beaute (b). Les D* et les correlations D*-leptons sont identifiees et ces dernieres servent a effecteur une separation claire entre les evenements rm Z^0to b| b et Z^0to c| c. On mesure la distribution de la variable de fragmentation x_{rm D^ *}=E_{rm D^*}/E _{rm faisceau} pour les D* produits dans les evenements rm Z^0 to c| c. Elle est notee f _{rm cto D^*}. Ce resultat est a la base d'une publication OPAL (1), avec trois autres methodes de separation etudiees en parallele, donnat la premiere mesure OPAL de f _{rm cto D^*} qui soit independante de toute modelisation de la fragmentation des quarks lourds, ainsi qu'une mesure de Gamma_{rm c| c} parmi les plus precises effectuees a ce jour, ou Gamma_{rm c| c} est la largeur partielle de la desintegration du Z^0 en une paire cc. En ce qui concerne les resultats obtenus dans le cadre de cette these, la valeur moyenne de la distribution f_ {rm cto D^*}, notee cto D^*}>, est donnee par:cto D^*}>=0.530+/-0.027 +/-0.022ou la premiere erreur est statistique, et la seconde est systematique. On mesure aussi le taux de production des mesons D*, donnee par: {Gamma({rm Z^0to D^ *}X)overGamma_{rm hadrons}}=0.207+/-0.007+/-0.017 ou Gamma_{rm hadrons } est la largeur totale de la desintegration du Z^0 en paires de qq des cinq saveurs. La separation entre evenements rm Z^0to b| b et Z^0 to c| c, dans lesquels sont produits des D* se desintegrant selon rm D^ *to D^0pito (Kpi)pi, nous donne:(DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI)La variable de fragmentation x_ {rm cto D^*} est utilisee pour tester les modeles des processes perturbatifs et non-perturbatifs qui entrent en jeu lors de la fragmentation des quarks b et c

  12. Study of aerosol penetration into filtering layers; Etude de la penetration des aerosols dans les couches filtrantes

    Parnianpour, H. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires


    In this work a radio-active aerosol is used to study the penetration of particles inside various filtering media by a layer technique. First of all the penetration of the active thoron deposit fixed on the atmospheric dust was examined for a series of filters which were considered to be representative of the various filtering materials used. From this series of tests it appears that the penetration of an ultrafine aerosol in a filter made up of fibrous matter involves two successive, different processes: the first part of the curve characterizes the surface effect, the second part which is practically exponential in form has a slope which depends on the test conditions and on the nature of the filter. The changes in the penetration as a function either of the porosity or of the rate of filtration yield only a qualitative check of the theory; in all cases the penetration is much greater than predicted. The last part of the work is devoted to an examination and a discussion of results obtained, and to various applications of the method, especially concerning the determination of the absorption coefficient for {alpha} particles by the matter. The changes in the absorption factor with filtering speed are particularly studied. (author) [French] On se propose dans ce travail d'etudier, avec un aerosol radioactif, la penetration des particules a l'interieur de differents milieux filtrants en utilisant une methode de feuilletage. On a tout d'abord examine la penetration du depot actif du thoron fixe sur les poussieres atmospheriques pour une serie de filtres que nous avons voulu representative des differents materiaux filtrants utilises. Il ressort de cette serie d'essais que la penetration d'un aerosol ultrafin dans un filtre compose de matiere fibreuse fait intervenir deux processus successifs differents: la premiere partie de courbe caracterise l'effet de surface; la seconde partie pratique- ment exponentielle ou la pente depend des

  13. Soil clean up by vapour extraction: parametrical study; Depollution des sols par extraction sous pression reduite: etude de quelques parametres

    Dutheil, C.


    Soil vapour extraction is a treatment process for soils polluted by volatile organic compounds. Its principle relies on the circulation of gaseous flow in soil by the application of a depression of some hundreds milli-bars. A parametrical study has been led on a soil artificially polluted by tri-chloro-ethene. It shows that the gaseous flow rate has a slight influence on pollutants extraction yield. This is due to rate limited mass transfer processes. Soil moisture plays a negative role on treatment efficiency because of the reduction of the porosity available for the gas circulation. Tests have been performed on a soil polluted by a complex mixture of organic pollutants to elaborate a methodology of technical feasibility assessment. This methodology aims at identifying and limiting risks of site rehabilitation failure. Tests results show that soil vapour extraction was inadequate to treat the soil tested in this study because of the strong affinity between a dense organic phase (grease) and chlorinated solvents. (author)

  14. Dynamic cardiovascular exploration with electron flow tomodensitometry; Etudes dynamiques cardiovasculaires par la tomodensitometrie par faisceau d`electrons

    Mousseaux, E.; Hernigou, A.; Auguste, M.; Gaux, J.C. [Hopital Broussais, 75 - Paris (France)


    Electron Beam Ct (EBCT) is still emerging as a new functional imaging procedure in providing high morphological studies and dynamic quantitative functional data. Morphological EBCT studies have previously proven their usefulness in pathologic conditions of the thoracic aorta, in congenital diseases, in cardiac masses or tumors. Functional studies achieved using cine mode and/or flow mode are used to assess both mobility and perfusion of structures. Such dynamic analysis have confirmed that their applications will have a major impact on the knowledge of cardiac physiology, the understanding of cardiovascular diseases, if not in daily patient care. For instance, in studies on ventricular function, among the imaging modalities in current use, EBCT is probably most accurate for the evaluation of systolic regional or global function. EBCT is a cross-sectional imaging methods which overcome an important limitation shared by most other imaging modalities, namely the superimposition of overlapping cardiac and thoracic structures. Since in the method high spatial, contrast, and temporal resolution tomography displays the myocardial wall itself, an accurate delineating of endocardial and epicardial contours in contiguous levels can be obtained. Further developments in computer-automated analysis from dynamic EBCT studies have to be carried out to gain clinical acceptance and to facilitate the routine. (authors). 9 refs. 7 figs.

  15. Contribution aux etudes de signaux radar de surfaces de mer et mise au point d'un traitement rapide

    Jousselme, Anne-Laure

    Dans le but d'utiliser un radar comme instrument de mesures oceanographiques, il apparai t necessaire de developper des techniques pour extraire les caracteristiques d'une surface de mer a partir du signal recu par le radar. La plupart des algorithmes existant considerent les images radar comme des photographies de la surface oceanique, negligeant l'effet de la vitesse de rotation du radar sur le signal, ainsi que le systeme de coordonnees polaires intrinseque de l'image radar. De plus, a cause de la loudeur des calculs, ces methodes ne peuvent fournir de resultats dans des applications en temps reel. La premiere partie de notra travail consiste a modeliser et quantifier l'effet de la distorsion du spectre oceanique provoquee par une vitesse de rotation du radar trop faible. Les resultats permettent de definir clairement les vitesses de rotation du radar pour lesquelles cette distorsion est negligeable. La deuxieme partie prospose un algorithme de traitement en temps reel qui extrait les informations caracteristiques principales de la surface de mer observee, i.e., la longueur d'onde et la direction des vagues. Cette estimation, basees sur une modelisation autoregressive offre une ouverture pour le traitement des signaux en temps reel. A travers cette approche, une succession de signaux unidimensionnels est traitee, ce qui conduit a l'elimination naturelle de la distorsion introduite dans le spectre du signal.

  16. Etude de la production de photons a grande impulsion transverse dans les collisions hadroniques avec le detecteur UA2

    Bourliaud, Martial


  17. Le changement comme tradition dans la recherche et la formation a la recherche en biotechnologie et en peripherie Etude de cas en sciences de la sante, sciences naturelles et genie

    Bourque, Claude Julie

    Le champ de la recherche scientifique et de la formation a la recherche est traverse depuis quelques dizaines d'annees par plusieurs courants et discours associes au changement, mais peu de travaux empiriques permettent de comprendre ce qui change concretement. C'est la contribution originale de cette these au champ de l'education, plus specifiquement a l'etude sociologique de l'enseignement superieur ou sont concentrees les activites liees a la triade thematique du programme doctoral dans lequel elle a ete produite : recherche, formation et pratique. L'enquete-terrain a ete realisee en 2009 et 2010 aupres de 808 repondants affilies a 60 etablissements au Quebec et a produit un vaste materiau de nature mixte (donnees quantitatives et qualitatives). Un portrait de la nebuleuse biotechnologique qui touche les secteurs des sciences de la sante, des sciences naturelles et du genie a ete realise. Ce domaine concerne des dizaines de disciplines et se revele de nature transdisciplinaire, mais les pratiques n'y sont pas davantage marquees par le changement que celles d'autres domaines connexes. Les dynamiques sociales ont fait l'objet d'analyses comparatives dans quatre contextes: le choix des programmes, des objets et des methodes, le financement, la diffusion et la planification de la carriere. Les resultats indiquent que les echanges entre les agents traditionnellement situes au coeur des activites de recherche dominent ces dynamiques dans tous les contextes etudies. L'etude des representations au fondement des pratiques a revele l'existence de trois ecoles de pensee qui coexistent dans le champ scientifique: academique, pragmatique et economiste. Ces ecoles permettent de categoriser les agents en fonction des zones de fractures qui marquent leurs oppositions tout en identifiant ce qu'ils ont en commun. Les representations et les pratiques liees a la formation temoignent d'un habitus plutot homogene, alors que les contradictions semblent plus souvent ancrees dans des

  18. Feasibility study for the installation of a small hydro electric power plant; Etude de faisabilite. Petite centrale hydro-electrique au lieu dit 'Sous les Roches' a Sonceboz

    Tissot, N. [MHyLab, Mini-Hydraulics Laboratory, Montcherand (Switzerland); Hausmann, H. [Hans Hausmann, Bevilard (Switzerland)


    This report for the Swiss Federal Office of Energy presents a technical, economical and ecological analysis of the feasibility of a small hydroelectric power plant at Sonceboz, in the Swiss Jura mountains. The power of the planed plant would typically be 500 kW for a water head of about 10 m. The study shows that, compared to one single turbine, a pair of Kaplan type turbines would be operational over a larger range of the river's water flow rate. This solution would be a little bit more costly but offer more flexibility for maintenance. Two maximum water flow rates are considered, 4.5 and 6 m{sup 3}/s respectively. According to the economical study, done with current electric kWh prices, both configurations are viable while the largest flow rate leads to a larger profit. The report is rounded up by a sensitivity analysis considering variations in annual power generation, electro-mechanical and construction cost as well as turbine efficiency. It indicates that this last factor could be crucial for the overall profitability. [French] Ce rapport est le resultat detaille de l'analyse technico-economique et ecologique de faisabilite de la realisation d'une petite centrale hydroelectrique basse chute qui pourrait exploiter une denivellation d'environ 10 m pour une puissance de l'ordre de 500 kW pres de Sonceboz dans le Jura suisse. L'etude montre que le couplage de deux turbines Kaplan offrirait une possibilite de fonctionnement sur une plus grande plage de flux ainsi qu'une plus grande flexibilite de maintenance, ceci pour un cout legerement superieur a l'option a une seule turbine. Les debits de 4.5 et 6 m{sup 3}/s sont consideres. L'etude economique montre que le debit de 6 m{sup 3}/s est plus rentable au prix de vente actuel du kWh. L'article se termine par une analyse de sensibilite sur les incertitudes concernant la production annuelle, les prix de l'electromecanique et du genie civil et le rendement des

  19. ETUDES ANALYTIQUES : Détection des OGM : du libre choix des consommateurs aux études de biovigilance

    Bertheau Yves


    Full Text Available Les récentes affaires de semences conventionnelles de colza et de maïs contaminées par des traces d’OGM ont à nouveau, s’il en était besoin, rappelé à notre bon souvenir les besoins en méthodes de détection et d’identification des OGM fiables et sensibles. Les développements se poursuivent, certes bien plus lentement qu’initialement espéré du fait du nombre important de facteurs à maîtriser et du caractère relativement inédit de ce travail. Concernant des matrices alimentaires variées, cette détection se heurte au manque de recul dans plusieurs domaines tels que celui de l’extraction et la purification d’acides nucléiques en quantité et en qualité. Bien que développées pour satisfaire aux besoins réglementaires européens concernant l’alimentation humaine, ces méthodes devraient être aisément applicables dans d’autres domaines concernés par les OGM (étude des transferts de gènes par flux pollinique, éventuels transferts horizontaux, suivi des acides nucléiques lors de l’ingestion.... Au-delà des OGM, les méthodes mises en œuvre devraient présenter un intérêt dans d’autres domaines comme la microbiologie, l’épidémiologie ou l’authentification des composants biologiques d’un produit.

  20. Infrared remote sensing of atmospheric aerosols; Apports du sondage infrarouge a l'etude des aerosols atmospheriques

    Pierangelo, C.


    The 2001 report from the Intergovernmental Panel on Climate Change emphasized the very low level of understanding of atmospheric aerosol effects on climate. These particles originate either from natural sources (dust, volcanic aerosols...) or from anthropogenic sources (sulfates, soot...). They are one of the main sources of uncertainty on climate change, partly because they show a very high spatio-temporal variability. Observation from space, being global and quasi-continuous, is therefore a first importance tool for aerosol studies. Remote sensing in the visible domain has been widely used to obtain a better characterization of these particles and their effect on solar radiation. On the opposite, remote sensing of aerosols in the infrared domain still remains marginal. Yet, not only the knowledge of the effect of aerosols on terrestrial radiation is needed for the evaluation of their total radiative forcing, but also infrared remote sensing provides a way to retrieve other aerosol characteristics (observations are possible at night and day, over land and sea). In this PhD dissertation, we show that aerosol optical depth, altitude and size can be retrieved from infrared sounder observations. We first study the sensitivity of aerosol optical properties to their micro-physical properties, we then develop a radiative transfer code for scattering medium adapted to the very high spectral resolution of the new generation sounder NASA-Aqua/AIRS, and we finally focus on the inverse problem. The applications shown here deal with Pinatubo stratospheric volcanic aerosol, observed with NOAA/HIRS, and with the building of an 8 year climatology of dust over sea and land from this sounder. Finally, from AIRS observations, we retrieve the optical depth at 10 {mu}m, the average altitude and the coarse mode effective radius of mineral dust over sea. (author)

  1. Etude de production et de caracterisation de biocharbons de panic erige (Panicum virgatum L.) obtenus par pyrolyse

    Pilon, Guillaume

    This research aimed at the production of biomass char under pyrolytic conditions, targeting biochar as soil amendment, while also considering its application as biocoal, either for bioenergy or subsequent upgrading. The production of biomass char was performed using two bench-scale, batch-type, fixed-bed reactors, each with an operating capacity of 1 and 25 gw.b. /batch, respectively. Switchgrass (Panicum virgatum) has been used for the tests. Production conditions studied implied temperatures of 300, 400 and 500 °C with short residence times (2.5 and 5 min). As well, the effect of using CO2 as vector gas has been compared to a common inert environment of N2. The effects of the previously mentioned parameters were correlated with some important physicochemical characteristics of biomass char. Analyses were also performed on complementary pyrolytic products (bio-oil and gas). The biomass char extraction was performed using a Soxhlet and dichloromethane was used as extracting solvent. The extracts were then characterized by GC-MS thus allowing the identification of several compounds. Specific pyrolysis conditions used at 300 °C - N2 with the 1 g/batch reactor, such as high heating rates as well as high convection conditions, presented advantegeous biomass char yields and properties, and, possible torrefaction process productivity improvement (in comparison to reported literature, such as Gilbert et al. [2009]). The char extracts as well as the bio-oils analysis (also performed using GC-MS), all generated from the 25 g/batch reactor, showed major differences among the compounds obtained from the CO2 and N2 environments, respectively. Several compounds observed in the char extracts appeared less concentrated in the CO2 environment vs N2, for the same reaction temperatures. As an example, at 400 °C, furfural was found only in char extracts from N2 environment as compared to the CO2 environment. Among all studied conditions (for both reactors), only naphthalene and

  2. Study of global control of VIRGO Central Interferometer; Etude du controle global de l'Interferometre Central de VIRGO

    Matone, Luca [Paris-11 Univ., 91 Orsay (France)


    The VIRGO project for the detection of gravitational waves will first operate in a test configuration, known as the Central Area Interferometer (CITF). The subject of this thesis consists of a study for the global control of this interferometer. In particular, the problems of auto-alignment and acquisition of lock are addressed. First, an investigation of the CITF optical response to longitudinal and angular mirror movements is given. On the basis of this study, we show how the ratio of photodiode signals can be used to detect and control the dark fringe when the CITF is far from its operating point (locked state). Furthermore, we present the simulation results of a quadrant photodiode configuration capable of reconstructing the mirrors' tilts once the CITF is in a locked state. The performance of a control system for the auto-alignment is then given. A study on the mode-cleaner prototype MC30 is then introduced in order to comprehend the process of lock acquisition by a linear feedback system for two different finesse values: F {approx_equal}100 and F {approx_equal} 1600. We define a threshold velocity for the mirrors' relative motion below which acquisition of lock is possible. A phenomenon, referred to as ringing effect, was observed and examined on the MC30 prototype in high finesse. The results of numerical calculations allowed us to fit measurement and estimate from them the cavity finesse as well as the mirrors' relative velocity during the resonance crossing. An empirical formula is then presented capable of determine the relative velocity from the positions of the oscillations' minima and maxima. An algorithm to guide into lock the CITF is then presented, consisting of an iterative procedure of velocity reconstruction and pulse application. A numerical calculation simulated the algorithm, the mirrors' motion, the optical response and the ADCs' process. As a result, acquisition times of the order of one second were observed: an

  3. Etude de solutions pour la mise en oeuvre d'une antenne a reflecteur bi-grille en polarisation circulaire

    Joyal, Marc-Andre

    Dual-gridded reflector (DGR) antennas are widely used on satellites. They consist of a cascade of two parabolic grids operating in orthogonal linear polarizations, each one having its own feed. Therefore, DGRs are actually two antennas in one structure, so they use less space on the satellite. Moreover, they provide excellent isolation between adjacent coverage areas. The disadvantage with these DGRs is that they work only in linear polarization (vertical and horizontal). In this thesis, two different solutions to design a circularly polarized (right and left hand circular polarizations) DGR are explored. The first one consists in the use of circular polarizers that are fixed on a conventional DGR. Those polarizers are surfaces that make the conversion between linear and circular polarizations. The other solution uses circular polarization selective surfaces (CPSSs) as reflectors on the DGR instead of the orthogonal grids. These CPSSs are structures that are transparent to one sense of circular polarization (say right hand circular polarization for instance), but that reflect the other sense (left hand circular polarization). The major part of this work is based on the first solution. A new circular polarizer design method is proposed. It allows a greater flexibility in the polarizer design than existing designs. The proposed technique is also modified in order to implement polarizers optimized for an oblique incidence, which is required for DGR applications. The second solution using CPSSs is only briefly explored. A new type of CPSS, implemented with a cascade of circular and linear polarizers, is proposed. This cascade CPSS has shown a broader bandwidth than those obtained with the resonant structures known so far. Also, the limitations of CPSSs are identified as to their use on DGRs. Finally, as a proof of concept, two simple prototypes of circularly polarized DGRs are presented. The first design is implemented with a circular polarizer and a metallic grid

  4. Improved methods for the generation of 24.5 keV neutron beams with possible application to boron neutron capture therapy

    Constantine, G.; Baker, L. J.; Taylor, N. P.


    The production of epithermal neutron beams, filtered to provide a spectrum in which a small energy range predominates, is of importance for radiobiological research and in the development and calibration of instruments for monitoring intermediate energy neutrons. The penetration characteristics of intermediate energy neutrons in tissue lead to the possibility of application in the field of neutron capture therapy if beams of sufficient intensity and adequate spectral properties can be generated. In this paper methods of utilising the 24.5 keV antiresonance in the iron neutron cross section are described, and the DENIS (depth enhanced neutron intense source) principle by which beam intensities may be optimised is explained. Calculations and experimental measurements in an in-core facility in the DIDO reactor at Harwell have indicated that a DENIS scatterer can achieve a 6-fold improvement in 24.5 keV beam intensity compared with a conventional titanium disc scatterer.

  5. Etude des melanges co-continus d'acide polylactique et d'amidon thermoplastique (PLA/TPS)

    Chavez Garcia, Maria Graciela

    resistance a la traction. La presence du compatibilisant dans la region co-continue affecte negativement cette resistance. En considerant que l'amidon est un biomateriau abondant, moins cher et plus rapidement biodegradable, son ajout dans le PLA presente l'avantage de reduire le cout tout en augmentant la vitesse de degradation du PLA. De plus, une structure continue poreuse de PLA produit par la technique de lixiviation selective a des applications potentielles soit comme materiau a degradation rapide ou encore, une fois la phase TPS retiree, comme substrat a porosite ouverte pour la fabrication de membranes, de supports cellulaires ou de filtres. Mots-cles : melanges immiscibles, acide polylactique, amidon thermoplastique, morphologie cocontinue, lixiviation selective, microtomographie R-X, materiau rigide poreux biodegradable.

  6. Fast neutron breeder reactor Rapsodie - situation of physics, hydraulic, thermal and dynamics studies and studies of stability early in 1963; Pile rapide rapsodie - point des etudes neutroniques, hydrauliques, thermiques et dynamiques et des etudes de stabilite au debut de l'annee 1963



    ) [French] Au debut de 1963, il a ete necessaire de faire un choix entre les deux combustibles etudies pour Rapsodie: l'alliage UPuMo avec double gainage Nb et acier inoxydable et l'oxyde mixte UO{sub 2}-PuO{sub 2}. Ce rapport donne les resultats des etudes menees avec les deux types de combustible. On rappelle d'abord les differents modeles qui ont ete etudies et on donne une description detaillee de coeurs alliage et oxyde tels qu'ils sont envisages au debut de 1963. On rapporte ensuite les principales caracteristiques neutroniques des deux coeurs: flux et spectre des neutrons, valeur des barres de securite - compensation, economie des neutrons, puissance specifique, fraction effective des neutrons retardes, temps de vie des neutrons prompts, coefficients de reactivite. On decrit les etudes et essais hydrauliques qui ont ete faits a propos de ces deux coeurs. On discute les criteres qui ont ete a l'origine des calculs de debits. On donne les resultats des essais de pertes de charge, de soulevement des assemblages, de vibration et d'ecoulement fin entre les aiguilles. On discute les constantes utilisees pour les calculs thermiques et on donne les temperatures maximales du sodium et des combustibles alliage et oxyde, les majorations dues aux points chauds et la limitation du taux de combustion de l'aiguille oxyde ayant pour origine la pression des gaz de fission. On rapporte les hypotheses qui ont ete utilisees pour les calculs dynamiques et l'on decrit les differents incidents qui ont ete etudies. On donne les resultats des calculs, pour chaque incident et pour chaque combustible et l'on montre que l'on peut eviter la fusion du combustible ou l'ebullition du sodium, meme dans le cas des hypotheses les plus pessimistes, en agissant sur les caracteristiques de la pile (valeur de la barre de pilotage ou puissance de la pile avec un seul circuit de refroidissement). La stabilite de la pile a ete evaluee avec les hypotheses

  7. Collection and processing of information in biological kinetics studies with radioactive tracers; Collecte et traitement de l'information dans les etudes de cinetique biologique avec traceurs radioactifs

    Remy, J.; Lafuma, J. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires


    The authors present an automatic method for the collection and treatment of information in biological kinetics experiments using radioactive tracers. The recording are made without any time constant on magnetic tape. The information recorded is sampled by a 400 channel multi-scale analyzer and transferred to punched cards. The digital analysis is done by an I.B.M. computer. The method is illustrated by an example: the hepatic fixation of colloidal gold in the pig. Its advantages and requirements are discussed. In the appendix are given the FORTRAN texts for two programmes used in treating the example presented. (authors) [French] Les auteurs presentent une methode automatique de collecte et de traitement de l'information dans les experiences de cinetique biologique utilisant les traceurs radioactifs. Les enregistrements sont realises sans constante de temps sur bande magnetique. L'information enregistree fait l'objet d'un echantillonnage a l'aide d'un analyseur a 400 canaux en mode multi-echelle puis est transferee sur cartes perforees. L'exploitation digitale est confiee a un ordinateur I.B.M.. La methode est illustree par un exemple d'etude de la fixation hepatique de l'or colloidal chez le porc. Ses avantages et ses exigences sont discutes. En annexe figurent les textes en FORTRAN de deux programmes utilises pour le traitement de l'exemple cite. (auteurs)

  8. A Study Of The Dilution Of Radio-Active Waste In The Rhone (1961); Etude de la dilution dans le rhone des effluents radioactifs du Centre de Marcoule (1961)

    Rodier, J.; Scheidhauer, J.; Marichal, M.; Court, R. [Commissariat a l' Energie Atomique, Centre de Production de Plutonium, Marcoule (France). Centre d' Etudes Nucleaires


    The discharge into the Rhone of liquid radio-active waste from the Marcoule Centre necessitates a large number of measurements, in particular chemical and radio-chemical analysis of the waste, itself and of the waters of the Rhone both above arid below the point of discharge. The results thus obtained during 1960 made it possible to evaluate the total amount of active waste discharged and its dilution in the receiving medium. A statistical study of the results of the analysis of the Rhone waters shows that a satisfactory dilution of the waste occurs rapidly; the experimental results obtained with an experimental discharge of rhodamine are thus confirmed. (authors) [French] Le rejet au Rhone des effluents radioactifs liquides produits sur le Centre de Marcoule donne lieu a un grand nombre de mesures et en particulier d'analyses chimiques et radio-chimiques des effluents eux-memes ainsi que des eaux du Rhone avant et apres rejet. Au cours de l'annee 1960, l'ensemble des resultats ainsi obtenus a permis de dresser un bilan des activites rejetees et de leur dispersion dans le milieu recepteur. Une etude statistique des resultats d'analyses des eaux du Rhone montre qu'une dilution satisfaisante des effluents s'effectue rapidement confirmant ainsi les resultats obtenus lors d'un rejet experimental de rhodamine. (auteurs)

  9. Contribution to the theoretical and experimental study of the electron-volt effect in N-P junctions; Contribution a l'etude theorique et experimentale de l'effet electronvoltaique dans les jonctions N-P

    Nguyen Van, Dong [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    , taking into account other phenomena which occur at low temperature. In the fourth part, results concerning the healing of the defects and protection measures against too energetic {beta} rays are described. A healing difference was observed between the lifetime and the conductivity. Finally, interesting results were obtained from experiments using a cadmium sulphide film to transform the {beta} particles of {sup 90}Sr-{sup 90}Y into photons. (author) [French] Le but propose dons le cadre de ce travail est d'etudier le comportement d'une jonction semi-conductrice sous l'action des rayons {beta}. L'etude a porte d'une part sur la conversion directe de l'energie rayonnee par une source radioactive en energie electrique utilisable a l'aide des jonctions N-P, et d'autre part sur la cinetique des defauts produits dans les cristaux de semi-conducteur par les rayons {beta} de grande energie. Dans la premiere partie du travail, on a essaye de completer les theories anterieures de l'effet electron-voltaique dans les jonctions en faisant une analyse mathematique de l'effet. Ceci a permis d'atteindre une equation unique dans laquelle figurent les parametres electriques et geometriques du semi-conducteur, de la jonction et les proprietes du rayonnement incident. D'autre part, on a etudie d'une maniere plus approfondie le courant de diffusion des porteurs de charge crees par le bombardement en tenant compte de tous les facteurs intervenant dans l'expression de l'efficacite de collection de charge d'une jonction. Dans la deuxieme partie, ou des experiences d'irradiation des jonctions N-P ont ete effectuees avec une source de {sup 90}Sr- {sup 90}Y, on a signale l'interet particulier d'une jonction d'arseniure de gallium susceptible de travailler a des temperatures relativement elevees (voisines de 100 deg. C). La troisieme partie presente l'etude des defauts crees dans un cristal de

  10. Blowing-machine representation of various meteorological situations for the study of rejection into the atmosphere; Essais de representation en soufflerie des diverses situations meteorologiques pour l'etude des rejets dans l'atmosphere

    Chassany, J.Ph. [CEA Marcoule, Centre de Production de Plutonium, 30 (France)


    A stratified blowing-machine has been built making it possible to introduce into the tests a vertical temperature gradient. The similitude conditions have been examined. The development tests have made it possible to observe and to film the shape of the smoke pall emitted by a chimney in different cases. Stationary waves have been obtained in steady state conditions and the cross-section of the pall has also been studied. It appears that certain diffusion studies justify the use of a stratified blowing-machine. (author) [French] Une soufflerie stratifiee permettant d'introduire dans les experimentations le gradient vertical de la temperature a ete realisee. Les conditions de similitude ont ete examinees. Des essais de mise au point ont permis d'observer et de filmer l'allure du panache de fumee emis par une cheminee dans differents cas. La formation d'ondes stationnaires en regime stable a ete obtenue et la section droite du panache a ete egalement etudiee. Il apparait que certaines etudes de diffusion doivent justifier l'emploi d'une soufflerie stratifiee. (auteur)

  11. The accelerator tube of ions of the generator Van de Graaff of the CEA. Survey of development. First results; Le tube accelerateur d'ions du generateur van de graapp du commissariat. Etude de developpement. Premiers resultats

    Bruck, H.; Prevot, F. [Commissariat a l' Energie Atomique, Saclay(France). Centre d' Etudes Nucleaires


    Rare are the Van de Graaff supplies whose tube doesn't collapse electrically to tensions and currents very lower to those that the generator can provide. We chose the general measurements: length and diameter, and put the accent on the survey of the individual element, so much to the mechanical viewpoint (installation, solidity, tightness and degassing), that to the electric viewpoint (to increase the electric rigidity of it). After modification the breakdown voltage as well as the performances of the tube have been improved greatly. (M.B.) [French] Rares sont les machines de Van de Graaff dont le tube ne s'effondre pas electriquement a des tensions et des courants bien inferieurs a ceux que le generateur peut fournir. Nous avons choisi les dimensions generales: longueur et diametre, et mis l'accent sur l'etude de l'element individuel, tant au point de vue mecanique (montage, solidite, etancheite et degazage), qu'au point de vue electrique (pour en augmenter la rigidite electrique). Apres modification la tension de claquage ainsi que les performances du tube ont ete grandement ameliorees. (M.B.)

  12. Bronchiolitis obliterans organizing pneumonia syndrome primed by radiation therapy to the breast. The Groupe d'Etudes et de Recherche sur les Maladies Orphelines Pulmonaires (GERM"O"P)

    Crestani, B; Valeyre, D; Roden, S; Wallaert, B; Dalphin, J C; Cordier, J F


    Reports of bronchiolitis obliterans organizing pneumonia (BOOP) occurring in women after radiation therapy for breast cancer have suggested that radiation to the lung could participate in the development of BOOP. We now describe the clinical, radiographic, functional, and bronchoalveolar lavage characteristics of this syndrome in a series of 15 patients reported to the Groupe d'Etudes et de Recherche sur les Maladies "Orphelines" Pulmonaires (GERM"O"P) in France. All 15 women (60 +/- 6 yr of age) fulfilled the following inclusion criteria: (1) radiation therapy to the breast within 12 mo, (2) general and/or respiratory symptoms lasting for at least 2 wk, (3) lung infiltrates outside the radiation port, and (4) no specific cause. The patients presented with fever, nonproductive cough, mild dyspnea, and peripheral alveolar opacities on chest radiograph with a characteristic migratory pattern. In five patients, BOOP was found at lung pathologic analysis. In all the patients dramatic improvement was obtained with corticosteroids, but relapses occurred in 12 patients while tapering or after stopping corticosteroids. This report demonstrates that a characteristic BOOP syndrome may occur after radiation therapy to the breast, including tangential radiation to the lung, thus suggesting that radiation therapy may prime the development of BOOP.

  13. Contribution to the study of the sintering mechanisms of uranium powders in the {alpha}, {beta}, and {gamma} phases; Contribution a l'etude des mecanismes de frittage de poudre d'uranium en phases {alpha}, {beta}, et {gamma}

    Pinteau, B. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    also followed by simple and differential thermal analysis. (author) [French] L'etude des mecanismes de frittage de poudre d'uranium d'origine caliothermique a ete effectuee sous vide par mesure dilatometrique en continu des retraits d'echantillons prealablement comprimes a temperature ordinaire sous atmosphere d'argon purifie. Les essais effectues dans les trois domaines {alpha}, {beta}, {gamma} ont permis de constater que le premier stade de frittoge semble regi par un mecanisme d'autodiffusion en volume; les valeurs des chaleurs d'activation des mecanismes de frittage trouves sont voisines de celles deduites lors des etudes sur l'autodiffusion en volume par la methode directe des radiotraceurs. Par ailleurs, dans le domaine {gamma} on a pu mettre en evidence un second mecanisme de frittage qui interesse des durees de frittage beaucoup plus longues, a chaleur d'activation beaucoup plus faible semblant indiquer qu'il s'agit d'un mecanisme d'elimination des pores par diffusion intergranulaire de lacunes. En outre, les essois dilatometriques permettent de mettre en evidence l'influence simultanee de deux facteurs principaux regissant cette etude: les joints de grains et les coefficients de diffusion. Dans une seconde partie, les echantillons frittes ont ete etudies par diverses methodes afin de determiner leur structure et certaines de leurs proprietes physiques. C'est ainsi que des examens metallographiques effectues apres polissage par bombardement ionique ont permis de determiner l'evolution de la porosite dans les trois phases {alpha}, {beta} et {gamma} ainsi que la structure et la nature des inclusions dans chaque echantillon. Par ailleurs des mesures de densite et de porosite ont ete effectuees. L'evolution des deux series de resultats permet de confirmer les examens dilatometriques et micrographiques precedents. Enfin, une etude dilatometrique detaillee des echantillons frittes en

  14. The synthesis and spectroscopic study of stable free radicals related to piperidine-n-oxyl, including a stable bi-radical; Syntheses et etudes spectroscopiques de radicaux libres piperidiniques et d'un biradical stable, du type nitroxyde

    Briere, R. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires, Laboratoire de chimie organique physique


    A new synthesis of di-tert-butyl nitroxide using the reaction between tert-butyl magnesium chloride and nitro-tert-butane is presented in the first section. Synthesis and investigation of stable free piperidine-N-oxyl radicals are described in the second section. All these nitroxides have been characterised by their I. R., U. V. and E. P. R. absorption spectra. The final section contains a description of the synthesis of a stable bi-radical of the nitroxide type by condensation of 2,2, 6, 6-tetramethyl-piperid-4-one-l-oxyl with hydrazine. (author) [French] La premiere partie expose une nouvelle methode de synthase du di-t-butyl nitroxyde, par action d'halogenures de t-butyl magnesium sur le nitro-t-butane (Rdt maximum 45 pour cert, purete 86 pour cent). Une etude de radicaux. libres stables pipericliniques est faite dans une seconde partie. Ces composes sont obtenus par oxydation de derives de la triacetonamine. Les caracteristiques spectroscopiques ultra-violette, infra-rouge, et paramagnetique electronique de ces radicaux sont donnees. La grande inertie chimique du groupement nitroxyde a permis la syn-these d'un biradical stable par formation d'azine d'une cetone radicalaire, ce qui fait 1'objet de la troisieme partie. (auteur)

  15. Validation of elastic cross section models for space radiation applications

    Werneth, C. M.; Xu, X.; Norman, R. B.; Ford, W. P.; Maung, K. M.


    The space radiation field is composed of energetic particles that pose both acute and long-term risks for astronauts in low earth orbit and beyond. In order to estimate radiation risk to crew members, the fluence of particles and biological response to the radiation must be known at tissue sites. Given that the spectral fluence at the boundary of the shielding material is characterized, radiation transport algorithms may be used to find the fluence of particles inside the shield and body, and the radio-biological response is estimated from experiments and models. The fidelity of the radiation spectrum inside the shield and body depends on radiation transport algorithms and the accuracy of the nuclear cross sections. In a recent study, self-consistent nuclear models based on multiple scattering theory that include the option to study relativistic kinematics were developed for the prediction of nuclear cross sections for space radiation applications. The aim of the current work is to use uncertainty quantification to ascertain the validity of the models as compared to a nuclear reaction database and to identify components of the models that can be improved in future efforts.

  16. Robotic Radiosurgery. Treating prostata cancer and related genitourinary applications

    Ponsky, Lee E. (ed.) [Case Western Reserve University School of Medicine, Cleveland, OH (United States). University Hospitals Case Medical Center


    Prostate cancer is the most common cancer among North American and European men, but its treatment continues to be problematic owing to serious side-effects, including erectile dysfunction, urinary incontinence, and potential lower GI complications. Robotic radiosurgery offers a novel, rapid, non-invasive outpatient treatment option for prostate cancer that combines robotics, advanced image-guided motion detection, and automated real-time corrective spatial positioning with submillimeter precision. This book examines all aspects of the treatment of prostate cancer with robotic radiosurgery. After introductory sections on radiosurgery as a multidisciplinary practice and specific issues relating to prostate cancer, the important challenge posed by prostate motion when administering radiation therapy is examined in depth, with detailed discussion as to how image-guided robotic radiosurgery overcomes this problem by continously identifying the precise location of the prostate throughout the course of treatment. A further major section is devoted to a discussion of techniques and potential radiobiological and clinical advantages of hypofractionated radiation delivery by means of robotic radiosurgery systems. The book closes by discussing other emerging genitourinary applications of robotic radiosurgery. All of the authors are experts in their field who present a persuasive case for this fascinating technique. (orig.)

  17. Genetic cytological and biochemical study of a tomato chlorophyll mutant of the xanthic type, obtained by irradiation of the seeds; Etude genetique, cytologique et biochimique d'un mutant chlorophyllien de tomate du type xantha, obtenu par irradiation de graines

    Lefort, M.; Duranton, J.; Galmiche, J.M.; Roux, E. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    Irradiation of Lycopersicum aesculantum seeds with increasing doses of X-rays and thermal neutrons leads to the appearance of chlorophyll mutations in the descendants of the irradiated seeds. A genetic study of one of these mutants of the xanthic type showed that it was a recessive mutant with typical mono-genetic separation, while the cytological study demonstrated that the differentiation of the plast stopped at the stage of elementary lamella. Finally it is shown that in the light, the mutation brings about a very large deviation of the carbon metabolism towards the synthesis of amino acids and proteins, at the expense of that of glucosides. (author) [French] L'irradiation de graines de Lycopersicum Aesculantum avec des doses croissantes de rayons X et de neutrons thermiques entraine l'apparition de mutations chlorophylliennes dans la descendance des graines irradiees. L'etude genetique d'un de ces mutants du type xantha a montre qu'il s'agissait d'un mutant recessif a disjonction monogenique typique, tandis que l'etude cytologique a revele que la differentiation du plaste s'arretait au stade de lamelles elementaires. Il est apparu enfin qu'a la lumiere la mutation entrainait une deviation tres importante du metabolisme du carbone vers la synthese des acides amines et des proteines, au detriment de celle des glucides. (auteur)

  18. Experimental study of heat exchange coefficients, critical heat flux and charge losses, using water-steam mixtures in turbulent flow in a vertical tube; Etude experimentale des coefficients d'echanges thermiques, des flux de chaleur critiques et des pertes de charge avec des melanges eau-vapeur en ecoulement turbulent dans un tube vertical

    Perroud, P.; De La Harpe, A.; Rebiere, J. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires


    Two stainless steel tubes were used (with diameters of 5 and 10 mm, lengths 400 and 600 mm respectively), heated electrically (50 Hz). The mixture flows from top to bottom. The work was carried out mainly on mixtures of high concentration (x > 0.1), at pressures between 50 and 60 kg/cm{sup 2}, flowing as a liquid film on the walls of the tube with droplets suspended in the central current of steam. By analysis of the heat transfer laws the exchange mechanisms were established, and the conditions under which the critical heat flux may be exceeded without danger of actual burnout were determined. In this way high output concentrations (x{sub s} > 0.9) may be obtained. An attempt has been made to find out to what extent existing correlation formulae can be used to account for the phenomena observed. It is shown that those dealing with exchange coefficients can only be applied in a first approximation in cases where exchange by convection is preponderant, and only below the critical flux. The formulae proposed by WAPD and CISE do not give a satisfactory estimation of the critical heat flux, and the essential reasons for this inadequacy are explained. Lastly, the Martinelli and Nelson method may be used to an approximation of 30 per cent for the calculation of charge losses. (author) [French] On a utilise deux tubes en acier inox (avec des diametres de 5 et 10 mm, et des longueurs respectives 400 et 600 mm) chauffes electriquement (50 Hz). Le melange s'ecoule de haut en bas. Les etudes ont porte plus specialement sur des melanges de titres eleves (x > 0,1) a des pressions comprises entre 60 et 90 kg/cm{sup 2} dont l'ecoulement se fait avec film liquide annulaire et gouttelettes en suspension dans le coeur de vapeur. Par l'analyse des lois de transfert de chaleur, on a precise les mecanismes d'echanges et l'on a d'autre part determine dans quelles conditions le flux de chaleur critique peut etre depasse sans danger de &apos

  19. Study of atmospheric tritium transfers in lettuce: kinetic study, equilibrium and organic incorporation during a continuous atmospheric exposure; Etude des transferts du tritium atmospherique chez la laitue: Etude cinetique, etat d'equilibre et integration du tritum sous forme organique lors d'une exposition atmospherique continue

    Boyer, C.


    This thesis has explored the mechanisms of tritium 'absorption and incorporation in a human-consumed plant, lettuce (Lactuca sativa L.), due to atmospheric exposure. Foliar uptake appears to play a key role in absorption of tritium as tissue free water tritium. Whatever the development stage and the light conditions, the specific activity in tissue free water reaches that of water vapour in air in several hours. The specific activity ratio is then about 0, 4. The time to reach equilibrium in soil is over 24 hours in most cases: the specific activity ratio ranges then 0, 01 to 0, 26. Incorporation rate of tissue free water tritium as organically-bound tritium has been estimated to 0, 13 to 0, 16 % h-l in average over the growing period of the plant, but marked variations are observed during growth. In particular, a significant increase appeared at the exponential growth stage. Deposition and diffusion of tritium in soil lead to significant OBT activities in soil. Results globally indicate equilibrium between the different environmental compartments (air, soil, plant). However, some experiments have revealed high OBT concentrations regarding atmospheric level exposure and ask for a possible phenomenon of local tritium accumulation in OBT for particular conditions of exposure. (author) [French] Ce travail de these a concerne l'etude des phenomenes d'absorption et d'incorporation sous forme organique du tritium dans un vegetal de consommation courante, la laitue (Lactuca sativa L.), en reponse a une exposition atmospherique. Il apparait que la voie foliaire joue un role primordial dans l'absorption du tritium au sein de l'eau tissulaire des plants. Quels que soient le stade de developpement des plants et les conditions d'eclairement, le temps necessaire pour atteindre l'equilibre des concentrations dans l'eau libre et dans la vapeur d'eau de l'air est de plusieurs heures; le rapport des concentrations est alors de

  20. Statistical pulses generator. Application to nuclear instrumentation (1962); Generateur d'impulsions aleatoires. Application a l'instrumentation nucleaire (1962)

    Beranger, R. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    This report describes a random pulses generator adapted to nuclear instrumentation. After a short survey on the statistical nature of electronic signals, the different ways for generating pulses with a Poisson's time-distribution are studied. The final generator built from a gaseous thyratron in a magnetic field is then described. Several tests are indicated : counting-rate stability, Pearson's criterion, distribution of time-intervals. Applications of the generator in 'whole testing' of nuclear instrumentation are then indicated for sealers, dead time measurements, time analyzers. In this application, pulse-height spectrums have been made by Poissonian sampling of a recurrent or random low-frequency signal. (author) [French] Cette etude decrit un generateur d'impulsions aleatoires et ses applications a l'instrumentation nucleaire. Apres un bref rappel sur la nature statistique des signaux en electronique nucleaire, sont passes en revue les principaux moyens d'obtenir des impulsions distribuees en temps suivant une loi de Poisson. Le generateur utilisant un thyratron a gaz dans un champ magnetique est ensuite decrit; diverses methodes de test sont appliquees (stabilite du taux de comptage, criterium de Pearson, spectre des intervalles ds temps). Les applications du generateur a l'electronique nucleaire dans le domaine des 'essais globaux' sont indiques: test des echelles de comptage et mesure des temps morts, test des analyseurs en temps apres division du taux de comptage par une puissance de deux, test des analyseurs multicanaux en amplitude. Pour cette derniere application, on a realise des spectres d'amplitudes suivant une loi connue, par echantillonnage poissonien d'un signal basse frequence recurrent ou aleatoire. (auteur)

  1. The impact on the radiobiological effect of lung squamous cancer cell line H520 with prolonged fraction delivery time%照射时间延长对肺鳞癌细胞株H520放射生物效应的影响

    李磊; 孟玲楠; 高纯子; 林珊; 李瑛; 韩波


    目的观察常规剂量分割照射模式下单次照射时间延长对肺癌细胞系H520放射生物效应的影响.方法 (1)肺鳞癌细胞株H520离体培养,分组进行照射,利用克隆形成实验计算细胞存活比率(SF);(2)细胞给予总剂量为2Gy、4Gy、6Gy、8Gy的照射,并按照每日单次照射时间的不同分为A组(照射2分钟组)、B1组(照射10分钟组)、B2组(照射30分钟组).观察延长照射时间对肺鳞癌细胞株H520存活比率的影响.结果 伴随单次照射总时间的延长,实验细胞的存活比率逐渐提高,接受照射总剂量为8Gy的H520细胞株,A组细胞存活比率为1.9%;B1组和B2组存活比率分别为2.35%和3.42%.A组与B2组之间的差异具有统计学意义(P<0.05).结论 常规剂量分割模式下延长单次照射时间,显著降低了放射治疗对H520细胞的生物效应.%Objective The purpose of this study was to observe the radiobiological effects of lung squamous cancer cell line H520 irradiated over prolonged single fraction delivery time in the conventional dose fractionated mode. Methods (1)The H520 cell lines were cultured in vitro, and then irradiated by groups. Its survival fractions(SF)were calculated with standard clonogenic assays.( 2 )The total doses of 2 Gy,4 Gy,6 Gy,8 Gy were given to the cells,which were divided into groups by different single fraction delivery time:group A( group irradiated for 2 mins ),group Bl( group irradiated for 10 mins ),and group B2( group irradiated for 30 mins ),and observed the impact on the survival fractions of H520 cell line with prolonged fraction delivery time. Results The cell surviving fractions increased when the interfraction interval was longer. The values of SF 8 Gy were 1. 9% in group A,2.35% in group B1,and increased to 3. 42% in group B2 ,respectively. The difference between group A and group B2 was statistically significant(P<0.05 ). Conclusion The prolonged fraction delivery time would significantly decrease the

  2. Current and Perspective Applications of Dense Plasma Focus Devices

    Gribkov, V. A.


    Dense Plasma Focus (DPF) devices' applications, which are intended to support the main-stream large-scale nuclear fusion programs (NFP) from one side (both in fundamental problems of Dense Magnetized Plasma physics and in its engineering issues) as well as elaborated for an immediate use in a number of fields from the other one, are described. In the first direction such problems as self-generated magnetic fields, implosion stability of plasma shells having a high aspect ratio, etc. are important for the Inertial Confinement Fusion (ICF) programs (e.g. as NIF), whereas different problems of current disruption phenomenon, plasma turbulence, mechanisms of generation of fast particles and neutrons in magnetized plasmas are of great interest for the large devices of the Magnetic Plasma Confinement—MPC (e.g. as ITER). In a sphere of the engineering problems of NFP it is shown that in particular the radiation material sciences have DPF as a very efficient tool for radiation tests of prospect materials and for improvement of their characteristics. In the field of broad-band current applications some results obtained in the fields of radiation material sciences, radiobiology, nuclear medicine, express Neutron Activation Analysis (including a single-shot interrogation of hidden illegal objects), dynamic non-destructive quality control, X-Ray microlithography and micromachining, and micro-radiography are presented. As the examples of the potential future applications it is proposed to use DPF as a powerful high-flux neutron source to generate very powerful pulses of neutrons in the nanosecond (ns) range of its duration for innovative experiments in nuclear physics, for the goals of radiation treatment of malignant tumors, for neutron tests of materials of the first wall, blankets and NFP device's constructions (with fluences up to 1 dpa per a year term), and ns pulses of fast electrons, neutrons and hard X-Rays for brachytherapy.

  3. Electrochemical study of chemical properties in ethanolamine and its mixtures with water; Etude electrochimique de proprietes chimiques dans l'ethanolamine et ses melanges avec l'eau

    Grall, M. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires


    This work is concerned with the study of acid-base reactions and of complex formation in ethanolamine and its mixtures with water. The ionic product of the solvent has been determined by an electro-chemical study of the H{sup +}/H{sub 2} system. The reduction curves for ethanolamine-water mixtures, for different acidities, have made it possible to follow the variations in the size of the pH domain as a function of the composition of the solvent. The form of this variation has been explained on the basis of the dielectric constant and the solvation of the proton by the ethanolamine. In the second part, the electrochemical systems of mercury have been studied by anodic polarography. In order to establish a parallel between the acid-base reactions and complex formation reactions, we have studied the stability of Hg (CN){sub 2} in water-ethanolamine mixtures. It has been possible to deduce the law for the variation of pK{sub c} with solvent composition. The representative graph of this function passes through a minimum for a proportion of about 50 per cent of ethanolamine as in the case of acids. This variation has been explained by the predominating influence of {epsilon} for ethanolamine propositions of over 50 per cent and by that of the solvation of Hg{sup 2+} for proportions of under 50 per cent. (author) [French] Ce travail porte sur l'etude des reactions acides-bases et de formation de complexes dans l'ethanolamine et ses melanges avec l'eau. Le produit ionique du solvant a pu etre determine par l'etude electro-chimique du systeme H{sup +}/H{sub 2}. Les courbes de reduction des melanges ethanolamine-eau, pour des acidites variables, ont permis de suivre les variations de l'etendue du domaine de pH, en fonction de la composition du solvant. L'allure de cette variation a ete expliquee en faisant intervenir la constante dielectrique et la solvatation du proton par l'ethanolamine. Dans une deuxieme partie, les systemes

  4. Contribution to the experimental study of the critical scattering of cold neutrons in iron; Contriiution a l'etude experimentale de la diffusion critique des neutrons froids par le fer

    Konstantinovic, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    The aim of the present work is a study of magnetic fluctuations which are produced in iron in the neighbourhood of the Curie temperature, by neutron scattering. We start by briefly recalling the theory of scattering of neutrons by magnetic substances and Landau's theory of second order phase transitions which enables one to derive the magnetic cross section near the Curie temperature. Following this is a description of the experimental apparatus after which we present the experimental results. The analysis of the results confirms the four-third law obeyed by the magnetic susceptibility near the Curie point, predicted by recent theories based on the Heisenberg model. However, the analysis reveals a non-zero relaxation time for the magnetic fluctuations at the Curie point, which is in disagreement with theoretical conclusions. (author) [French] L'objet du present travail est l'etude des fluctuations d'aimantation qui prennent naissance dans le fer au voisinage de sa temperature de Curie par la diffusion des neutrons. Nous commencons par rappeler brievement les generalites sur la diffusion des neutrons par les substances magnetiques et la theorie de Landau des transitions de phase du second ordre qui permet de deriver une expression de la section efficace magnetique pres de la temperature de Curie. Ensuite, apres la description du dispositif experimental, nous presentons les resultats experimentaux. L'analyse de ces resultats confirme les theories recentes suivant le modele d'Heisenberg en ce qui concerne la 'loi en 4/3' de la susceptibilite magnetique au voisinage du point de Curie; mais par ailleurs elle revele l'existence d'un temps de relaxation des fluctuations d'aimantation non nul en ce point, ce qui est en desaccord avec les previsions theoriques actuelles. (auteur)

  5. Efficacy and safety of the combination paclitaxel/carboplatin in patients with previously treated advanced ovarian carcinoma: a multicenter French Groupe des Investigateurs Nationaux pour l'Etude des Cancers Ovariens phase II study.

    Pujade-Lauraine, E; Guastalla, J P; Weber, B; Curé, H; Orfeuvre, H; Mousseau, M; Vincent, P; Diéras, V; Tubiana-Mathieu, N; Jacquin, J P; Mignot, L; Leduc, B; Paraïso, D; Viens, P


    The French Groupe des Investigateurs Nationaux pour l'Etude des Cancers Ovariens (GINECO) conducted a multicenter phase II study of carboplatin and paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) to evaluate the efficacy and side effects of this combination in pretreated advanced ovarian cancer. Patients with progressive ovarian carcinoma during or after platinum-based chemotherapy received paclitaxel 175 mg/m2 intravenously over 3 hours followed by intravenous carboplatin over 30 minutes every 4 weeks. The dose of carboplatin was calculated using a projected area under the concentration-time curve of 5 mg/mL x min. Of the 50 patients entered, 50 were evaluable for toxicity and 42 for response. There were eight complete and 10 partial responses, for an overall response rate of 43% (95% confidence interval, 28% to 56%). Overall response rates in platinum refractory patients and in those with early (> or = 3 and or = 12 months) relapse was 28%, 33%, and 71%, respectively. Median response duration, progression-free survival, and overall survivals were 8, 6, and 14 months, respectively. The most frequent and severe toxicity was myelosuppression. Grades 3 and 4 neutropenia occurred in 30% and 23% of cycles, and granulocyte colony-stimulating factor was administered in 6%. Only one case of neutropenic fever was observed. Grades 3 and 4 thrombocytopenia occurred in 3% and 1% of cycles, respectively. Alopecia and moderate nausea or vomiting were frequent. Transitory peripheral neuropathy was present in 45% of patients but was severe in only one patient. One early death was observed due to progressive disease and possibly to therapy. The combination of paclitaxel 175 mg/m2 as a 3-hour infusion and carboplatin dosed to an area under the concentration-time curve of 5 is an effective therapy in patients previously treated with platinum-based chemotherapy and may be administered safely to outpatients who relapse after one or two lines of chemotherapy.

  6. Etude de la résistance aux antibiotiques de Pseudomonas aeruginosa au niveau de différents hôpitaux de l’ouest algérien



    Année Universitaire: 2014-2015 Etude de la résistance aux antibiotiques de Pseudomonas aeruginosa au niveau de différents hôpitaux de l’ouest algérien ملخّص عصيّات Pseudomonas aeruginosa هي ج ا رثيم ممرضة انتهازية مسؤولة أساسا عن الالتهابات المكتسبة وتُظهر هذه البكتيريا قدرة التكيّف تجاه المضادّات الحيويّة ممّا يؤدّي إلى مشاكل علاجيّة حادّة في كثير من الأحيان. مجموع 217 جرثوم من عصيّات P. aeruginosa تمّ عزلها ما بين يناير 9002 ونوفمبر 2012 ، في مختلف الوحدات من ثلاثة مستشفيا...

  7. Magnetic study of a few antiferromagnets in very-strong pulsed fields (450 kOE); Etude magnetique de quelques antiferromagnetiques dans des champs pulses tres intenses (450 k OE)

    Krebs, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    In this thesis we describe a pulsed field device with which we obtain magnetization curves up to 450 kOE at all temperatures between 1. 6 and 300. We have studied the 'spin-flopping'(and therefore the anisotropy) in MnF{sub 2} versus temperature, below the Neel point. We have also studied the antiferromagnets MnSO{sub 4}. and MnSO{sub 4}.H{sub 2}O which have revealed saturation fields respectively of 250 kOE and 320 kOE. (author) [French] Ce memoire est consacre a la fabrication et a la mise au point d'un appareillage utilisant la decharge d'une batterie de condensateurs, afin de faire des mesures d'aimantation en champs pulses jusqu'a 450 kOE a toute temperature entre 1,6 K et 300 K. Nous avons etudie le deplacement de la transition de 'spin-flopping' dans MnF{sub 2} en fonction de la temperature et nous en avons deduit la variation de la constante d'anisotropie en fonction de T au-dessous du point de Neel. Nous avons egalement fait l'etude magnetique des antiferromagnetiques MnSO{sub 4} et MnSO{sub 4}.H{sub 2}O et nous avons mis en evidence la saturation de ces deux substances pour des champs respectifs de 250 kOE et 320 kOE. (auteur)

  8. Contribution to the theoretical study of order-disorder phenomena in the electrical properties of alloys (1963); Contribution a l'etude theorique des phenomenes d'ordre dans les proprietes electriques des alliages (1963)

    Beal, M.T. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires


    We have study theoretically the ordering of alloys and its influence an electrical resistivity. We have looked at the cases of concentrated, non magnetic alloys such as Cu Zn {beta} or Cu{sub 3}Au and of diluted, magnetic alloys such as noble matrix with rare earth impurities. In both cases, a simple method of molecular field with nearest neighbour interactions is used. Scattering cross sections are calculated with free electrons and Born approximation. The electrical properties are described with a good accuracy by single diffusions on each center (long range order). But some anomalies near to the ordering temperature are caused by double diffusions on pairs of interacting atoms or spins (local order). (author) [French] On presente une etude theorique des phenomenes d'ordre et de leur influence sur les proprietes electriques des alliages. Deux cas sont envisages: celui des alliages non magnetiques concentres, tels que Cu Zn {beta} ou Cu{sub 3}Au et celui d'alliages magnetiques tres dilues du type matrice noble impuretes de terres rares. Dans les deux cas on utilise une methode simple de champ moleculaire avec interactions entre plus proches voisins seulement. Les sections efficaces de diffusion sont calculees dans un modele d'electrons libres et dans l'approximation de Born. Les proprietes electriques sont decrites en premiere approximation par les diffusions simples sur chaque atome ou spin (ordre a longue distance). Mais elles presentent des anomalies a la temperature d'ordre dues aux diffusions doubles sur des paires d'atomes ou de spins plus proches voisins (ordre local). (auteur)

  9. Contribution to the study of the thermal fission process for uranium 235 (1964); Contribution a l'etude du processus de la fission thermique de l'uranium 235 (1964)

    Chahrtache, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    This report deals with the study of the distribution of the masses of the fragments produced by the disintegration of the U-236 nucleus, formed when a U-235 nucleus captures a thermal neutron. The experimental method chosen consists in the simultaneous measurement using p-n silicon junction detectors of the energies of the two fragments emitted in coincidence. This measurement is first made by a conditioned analysis of the energy of one of the fragments and then by a two dimensional analysis of the energies of the two fragments. Systematic results, are obtained concerning the distribution of the masses for different values of the total kinetic energy. The five structures appearing both for the mass distributions and for the energies of the fragments are studied and discussed. Generally speaking, our results are in agreement with those obtained by the time-of-flight method. (author) [French] Le present rapport a pour objet t'etude de la distribution des masses des fragments emis lors de la fission du noyau U-236, forme par capture d'un neutron thermique par un noyau d'U-235. La methode experimentale choisie consiste en la mesure simultanee - a l'aide de detecteurs a jonction p-n au silicium des energies des deux fragments emis en coincidence. Cette mesure est d'abord effectuee par analyse conditionnee de l'energie de l'un des fragments puis par analyse bidimensionnelle des energies des deux fragments. Des resultats systematiques sont obtenus sur les distributions des masses pour differentes valeurs de l'energie cinetique totale. Les 'structures fines' apparaissant tant sur les distributions des masses que sur celles des energies des fragments sont egalement etudiees et discutees. D'une facon generale, nos resultats sont en accord avec ceux obtenus par la methode du temps de vol. (auteur)

  10. Contribution to the study of turbulent flow in cylindrical tubing with porous walls; Contribution a l'etude de l'ecoulement turbulent dans une conduite cylindrique a paroi poreuse

    Burnage, H


    A theoretical study has been made of a fully developed turbulent flow in cylindrical tubing of circular cross-section subjected to a uniform suction through the walls. This study has made it possible to find a relationship giving the friction coefficient at the wall in terms of the amount of local suction and of the longitudinal static pressure gradient. A method for calculating the Reynolds tensions from the pressure measurements has been devised. An experimental system has been developed. Pressure measurements have been made. By using experimental results it has been possible to obtain a semi empirical expression for the friction coefficient at the wall, in terms of the amount of suction of the inlet Reynolds number, and of the abscissa. (author) [French] Une etude theorique de refoulement turbulent pleinement developpe dans une conduite cylindrique de section circulaire soumise a une aspiration parietale uniforme a ete entreprise. Elle a permis de trouver une relation donnant le coefficient de frottement a la paroi en fonction du taux d'aspiration local et du gradient de pression statique longitudinal. Une methode de calcul des tensions de Reynolds a partir des mesures de pression a ete etablie. Un dispositif experimental a ete realise et mis au point. Des mesures de pression ont ete effectuees. L'utilisation des resultats experimentaux a permis d'obtenir une expression semi-empirique du coefficient de frottement a la paroi en fonction du taux d'aspiration, du nombre de Reynolds d'entree et de l'abscisse. (auteur)

  11. Study of a one-dimensional model for a system of interacting fermions; Etude d'un modele a une dimension pour un systeme de fermions en interaction

    Gaudin, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    The subject of this thesis is a one dimensional model for a quantum system of fermions with attractive or repulsive interaction. The eigenvalues and eigenfunctions of the Hamiltonian with periodic boundary conditions are exactly determined. The knowledge of the spectrum is essentially applied on the study of the attractive gas, characterized by the presence of 'pairs' or two particles bound states. This system can be described as a gas of 'one dimensional deuterons', which has some analogy with a boson gas. Some extensive properties of the ground state have been discussed for example energy as a function of the density and magnetization, for all the values of the coupling constant. The analytic properties of the energy function are studied, but not completely resolved. Finally the elementary excitations of the phonon type are considered and the dispersion curves are given. (author) [French] On etudie un modele a une dimension pour un systeme quantique de fermions en interaction attractive ou repulsive dans un volume donne. L'ensemble des niveaux d'energie et des etats propres du systeme est determine exactement. La connaissance du spectre est surtout appliquee a l'etude du gaz attractif, interessant par la presence de 'paires' ou etats lies a deux particules. On peut decrire ce systeme comme un gaz de 'deuterons a une dimension' qui possede quelque ressemblance avec un systeme de bosons. Quelques proprietes extensives de l'etat fondamental sont donnees, comme l'energie en fonction de la densite et de la magnetisation totale, pour toute valeur de la constante de couplage. Les proprietes analytiques de la fonction energie sont etudiees sans etre completement elucidees. On aborde enfin les excitations elementaires du systeme et on etablit la courbe de dispersion d'une excitation de type phonon. (auteur)

  12. Study of the structure of light neutron rich nucleus with the Tonnerre array; Etude de la structure de noyaux legers riches en neutrons a l'aide du multidetecteur Tonnerre

    Pietri, St


    This work concern the technical development made on the multidetector TONNERRE and the study of the {sup 34}Si nucleus by a complete beta-neutron-gamma spectroscopy. In the first part various tests performed on modules of the detector in the 'Centre d'Etude de Bruyere le Chatel' are presented. A modification of the embassies of the photomultipliers tubes allows to gain more than 50% in the neutron efficiency and to obtain a threshold lower than 300 keV for the neutron energy. A complete C++ simulation of the neutron propagation in the array was carried out. It explains that the slow component of the light output of the scintillator may be responsible of the shape of the time-of-flight spectrum. The second part of these report presents the experiment devoted to the study of the structure of the {sup 34}Si from the beta decay of the {sup 34}Al. It was performed at the GANIL facility using the TONNERRE array and germanium of ENOGAM. The {sup 34}Al was produced by projectile fragmentation of a {sup 36}S beam of 50 MeV/A in a target of {sup 9}Be. A complete beta scheme of the {sup 34}Al is proposed. Eight neutron lines following the {sup 34}Al decay were observed for the first time. Finally we suggest that a monopolar transition could occur in the {sup 34}Si nucleus signing a O{sup +}{sub 2} state at 2133 keV. (author)

  13. Study of some ion exchange minerals which can be used in water at high temperature; Etude de quelques echangeurs mineraux utilisables dans l'eau a haute temperature

    Hure, J.; Platzer, R.; Bittel, R. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Fourre, J. [Societe le Carbone Lorraine, 75 - Paris (France); Wey, R. [Faculte des Sciences de Strasbourg, Lab. de Mineralogie, 67 (France)


    these impurities (that is to say capable of de-mineralizing polluted water). This paper describes the preliminary results of the investigation. (author) [French] L'etude de l'utilisation des echangeurs d'ions a haute temperature a ete essentiellement faite en vue de l'epuration de l'eau des reacteurs. On connait l'interet qu'il y a a garder dans un circuit de reacteur de l'eau de tres haute resistivite (plusieurs centaines a quelques millions {omega}.cm): abaissement de la corrosion, abaissement du taux de radiolyse, abaissement de la radioactivite des circuits et canalisations, les elements autres que les constituants de l'eau transportes par celle-ci devenant generalement radioactifs par leur passage au coeur du reacteur. Si la circulation d'eau se fait a des temperatures inferieures a 45 deg. C, les resines echangeuses d'ions organiques utilisees en lit melange resolvent tres bien le probleme de l'epuration en continu. Par contre, pour des temperatures plus elevees surtout au-dessus de 100 deg. C, leur utilisation n'est pas possible, la degradation de ces hauts polymeres etant tres rapide. De meme, l'action des rayonnements, par exemple ceux des produits fixes par les echangeurs d'ions, detruit irremediablement les chaines organiques constituant le squelette de ces echangeurs. Nous avons donc cherche d'es composes pouvant assurer une bonne deionisation de l'eau, mais de structures telles qu'elles ne soient pas deteriorees par l'action de la temperature et des rayonnements. Nous nous sommes particulierement orientes dans trois voies: - echangeurs d'ions naturels a structure minerale (argile du type montmorillonite), - composes mineraux naturels traites pour leur conferer les proprietes d'echangeurs d'ions (charbons actives), - composes mineraux synthetiques (sels tres peu solubles, phosphate et hydroxyde de zirconium et de thorium). Dans ces etudes, nous nous

  14. Separation of radio-cesium using potassium cobalt ferrocyanides. Application to radioactive waste and sea water; Separation des radiocesium par le ferrocyanure de cobalt potassium application aux eaux residuaires et marines

    Scheidhauer, J.; Vergnaud, G.; Flamant, A. [Commissariat a l' Energie Atomique, la Hague, 50 - Cherbourg (France). Section de protection contre les radiations


    This work concerns the separation of radiocesium using ion-exchange on the ferrocyanide of cobalt and potassium. The factors studied, and which could affect this separation are: the pH, the amount of ion-exchanger used, the rate of flow of the sample, the grain-size of the ion-exchanger, the selectivity. The operational technique used is described, as well as its particular application to sea-water. (authors) [French] L'etude porte sur la separation des radiocesium par echange d'ion sur du ferrocyanure de cobalt et de potassium. Les parametres etudies et pouvant influencer cette separation sont: le pH, la quantite d'echangeur d'ion utilise, la vitesse d'ecoulement de l'echantillon, la granulometrie de l'echangeur d'ion, la selectivite. La technique operatoire adoptee est decrite, ainsi que son application particuliere a l'eau de mer. (auteurs)

  15. Experimental study of a separated jets burner: application to the natural gas-pure oxygen combustion; Etude experimentale du comportement de bruleurs a jets separes: application a la combustion gaz naturel-oxygene pur

    Salentey, L.


    The evolution of pollution standards and the optimisation of furnaces performances require a development of new burner generation and also the improvement of combustion techniques. Actually, the use of oxy-combustion in separated jets burners offers interesting prospects for NO{sub x} emission reduction and on the modularity of flames properties (lift off, flame front topology, flame length). The complex geometry of those burners leads to several problems like the three-dimensional character of the flow, which may sometimes disturb the flame stability as flames are lifted above the burner. This experimental study deals with a simplified version of that kind of burner constituted with a central natural gas jet surrounded by two oxygen jets. Primary, the study of non-reactive jet was planned in order to understand dynamic and mixture phenomena involved between jets and to provide a database useful for the computer code validation. The reactive flow developed in a furnace, which simulates the real conditions, had been characterised. The studies of the dynamic field using Laser Doppler Velocimetry (LDV) and of the turbulent mixture by conditional Laser tomography were supplemented in combustion by the visualisation of the spontaneous emission of radical OH, in the initial and final zone of the oxy-flames, like by the measurement of pollutants like NO{sub x} and soot. The measurements carried out while varying speeds of injection as well as the gap between the jets made possible the highlight of the influence of these parameters upon the stabilisation of the oxy-flames as well as the modification of the topology and the characteristics of the flows. The comparison of the measurements made in non-reactive and reactive flow shows the influence of oxy-combustion on the dynamic and scalar development of the flow for this type of burners. (author)

  16. Modelling and experimental study of the behavior of radon and radon decay products in an enclosure. Application to houses; Modelisation et etude experimentale du comportement du radon et de ses descendants dans une enceinte confinee. Application a une habitation

    Gouronnec, A.M.


    Since the eighties, more and more studies were performed about radon and its decay products in houses with one of the aim being the estimation of the dose received by their inhabitants. Then, the principal objective of this work is to describe the behaviour of radon and its decay products within a dwelling. In the first part to the report, a few definitions are given and data from literature give an idea of indoor radon and radon decay products activities and/or size distribution. Aspects of dosimetry are presented too. In the second part of the work, a mathematical model, called `PRADDO` of Physic of Radon and radon Decay products in Domestic environment is developed on the basis of the classical model written by Jacobi in 1972. On the one hand, it has to predict radon decay products activities in systems consisting in one or more enclosure(s), from radon activity and from ambient aerosol concentration and size distribution. On the other hand, one part of the model is assigned to study the influence of the entry model parameters variation on the calculated quantities. Then, in the third part of the work, two experimental studies are realised in order to compare measurements to modelization. The first experimentation is a laboratory work, made on the test bench ICARE from IPSN, and the second one consists in describing the basement of an occupied house from Brittany. In the two cases, the comparison between experiments and modelling shows a good agreement if particles are present in the air, but any conclusion is made when is no aerosol in the enclosure. (author). 158 refs., 81 figs., 42 tabs.

  17. Study of macro-porosity using X ray tomodensitometry. Application to the leaching monitoring of solidification-stabilization samples; Etude de la macroporosite par tomodensitometrie-X. Application au suivi de la lixiviation d`eprouvettes de solidification stabilisation

    Chatelet, L. [Cered, France Dechets, 27 - Saint-Marcel (France); Yvon, J. [Ecole Nationale Superieure de Geologie Appliquee et de Prospection Miniere, 54 - Vandoeurvre-les-Nancy (France); Bottero, J.Y. [CNRS, Cerege FU 17, 13 - Les Milles (France); Blum, A. [Hopital de Brabois-Vandoeuvre, 54 - Nancy (France); Champenois, M.; Ailleres, L. [CRPG, 54 - Vandoeuvre-les-Nancy (France); Bouchelaghem, A. [Inertec, 92 - Nanterre (France)


    An analysis protocol based on X-ray tomodensitometry for the section imaging of waste-cement mixture samples, using an X ray scanner, is described. The technique is applied to the examination of the porosity of waste-cement samples and its evolution after each leaching stage is qualified and quantified through image analysis. The results are used to monitor the leaching rate in the samples and its variation with time

  18. Reactive turbulent flow CFD study in supercritical water oxidation process: application to a stirred double shell reactor; Etude par simulation numerique des ecoulements turbulents reactifs dans les reacteurs d'oxydation hydrothermale: application a un reacteur agite double enveloppe

    Moussiere, S


    Supercritical water oxidation is an innovative process to treat organic liquid waste which uses supercritical water properties to mix efficiency the oxidant and the organic compounds. The reactor is a stirred double shell reactor. In the step of adaptation to nuclear constraints, the computational fluid dynamic modeling is a good tool to know required temperature field in the reactor for safety analysis. Firstly, the CFD modeling of tubular reactor confirms the hypothesis of an incompressible fluid and the use of k-w turbulence model to represent the hydrodynamic. Moreover, the EDC model is as efficiency as the kinetic to compute the reaction rate in this reactor. Secondly, the study of turbulent flow in the double shell reactor confirms the use of 2D axisymmetric geometry instead of 3D geometry to compute heat transfer. Moreover, this study reports that water-air mixing is not in single phase. The reactive turbulent flow is well represented by EDC model after adaptation of initial conditions. The reaction rate in supercritical water oxidation reactor is mainly controlled by the mixing. (author)

  19. Quantum mechanical study of molecular collisions at ultra-low energy: applications to alkali and alkaline-earth systems; Etude quantique de collisions moleculaires a ultra-basse energie: applications aux alcalins et alcalino-terreux

    Quemener, G


    In order to investigate the collisional processes which occur during the formation of molecular Bose-Einstein condensates, a time-independent quantum mechanical formalism, based on hyperspherical coordinates, has been applied to the study of atom-diatom dynamics at ultra-low energies. We present theoretical results for three alkali systems, each composed of lithium, sodium or potassium atoms, and for an alkaline-earth system composed of calcium atoms. We also study dynamics at large and positive atom-atom scattering length. Evidence for the suppression of inelastic processes in a fermionic system is given, as well as a linear relation between the atom-diatom scattering length and the atom-atom scattering length. (author)

  20. Study of the {sup 241}Am in fresh water. Application to Rh e ecosystem; Etude des transferts de L'{sup 241}Am en eau douce. Application a l'ecosysteme rhodanien

    Veran, M.P.; Garnier-Laplace, J.; Baudin, J.P. [CEA Cadarache, Inst. de Protection et de Surete Nucleaire (IPSN), 13 - Saint-Paul-lez-Durance (France)


    The {sup 241}Am transfers are quantified in the heart of a model ecosystem, representative of the aquatic medium downstream the site of Marcoule. The dominating phenomenon of adsorption governs the distribution of Am in the ecosystem. The capacities of bioaccumulation are more important for the primary producers, the zooplankton and the filter molluscs. The results show the key role of the benthic fauna able to mobilize {sup 241}Am fixed on the sediment and the importance of the feeding to explain the contamination of the omnivorous fishes. The dreissensia can be used as bio indicator of radio contamination by transuranium elements. (N.C.)

  1. The radioinduced membranes injuries as biological dose indicators: mechanisms of studies and practical applications; Les dommages membranaires radio-induits comme bio-indicateurs de dose: etudes des mecanismes et applications pratiques

    Vincent-Genod, Lucie


    After an accidental overexposure, the assessment of the received dose in biological dosimetry is performed by a method based on the effects of irradiation on the DNA molecule. But this technique shows some limitations; therefore we tried to find new bio-sensors of radiation exposure. We have pointed out that membrane is a critical target of ionising radiation after an in vitro and in vivo overexposure. In vitro, these modifications were involved in the radio-induced apoptotic pathway. The measure of membrane fluidity allowed us to obtain an overall view of cellular membrane. Moreover, in vivo, by changing the lipid nutritional status of animals, our results displayed the important role played by membrane lipid composition in radio-induced membrane alterations. Besides, membrane effects were adjusted by the extracellular physiological control, and in particular by the damages on membrane fatty acid pattern. Finally, we have tested the use of membrane fluidity index as a bio-sensor of radiation exposure on in vivo models and blood samples from medical total body irradiated patients. The results achieved on animal models suggested that the membrane fluidity index was a bio-sensor of radiation exposure. Nevertheless, the observations realised on patients highlight that the effect of the first dose fraction of the radiotherapy treatment had some difficulties to be noticed. Indeed, the combined treatment: chemotherapy and radiotherapy disturbed the membrane fluidity index measures. To conclude, whereas this parameter was not a bio-sensor of irradiation exposure usable in biological dosimetry, it may allow us to assess the radio-induced damages and their cellular but also tissue impacts. (author)

  2. Heat and mass transfer in multi-scale porous structures: application to Diesel particulate filters modelling; Transferts de chaleur et de masse dans des structures poreuses multi-echelles: application a l'etude des filtres a particules Diesel

    Oxarango, L.


    Ceramic filters appear to be the most promising solution to deal with the future emission standard requirements for diesel powered vehicles. Indeed, this type of Diesel Particulate Filters provides suitable characteristics for high efficiency soot collection. However, this filtration process is characterised by a dramatic increase of the pressure drop imposed in the exhaust line. Thus, the filter has to be cleaned periodically to insure the proper engine operating conditions. This regeneration phase is based on the oxidation of the carbon particles within the apparatus. This complex thermal process is critical for the safety working of Diesel Particulate Filters. Indeed, thermal stresses induced by the heat released during soot oxidation are involved in most of the filter breaking scenario. Numerous geometrical parameters defining the complex multi-scale structure of the apparatus could influence its thermal response. Thus, the geometrical optimization of these filters is a major problematic for the development of new products. This study aims at modelling heat and mass transfer phenomenon within Diesel Particulate Filters. The studied geometrical configuration is based on a ceramic honeycomb with porous walls and alternately plugged channel known as wall-flow DPF. In a first part, the gas flow, particles transport and collection are considered. Given the apparatus particular structure, the problem has to be treated considering various spatial length-scales. The filtering walls are characterised by a micrometric porous structure. The flow modelling with the Darcy law requires determining a particular effective permeability. The laminar flow problem in millimetric channels with wall suction (or injection) is studied. The asymptotic solution for flow in two-dimensional channels is used to derive a one-dimensional system preserving mass and momentum balances. This approach is then extended to the square channel configuration using direct numerical simulations. The particle collection process is modelled as a simple cake layer formation with respect to the gas flow properties. A parametric study carried out on periodic representative cells evidence the heterogeneous distribution of soot along the filter channel. Then, the non-periodic multi-channel case is considered. The particle loading appears to be weakly sensitive to local heterogeneities imposed in a single channel. Finally, the mass and momentum equations are expressed under a macroscopic form. The filtration process could then be simulated in the whole apparatus. During this study, a particular care has been taken to validate each model against experiment. In a second part, the thermal problem is considered. The phenomena occurring at the micrometric scale are taken into account. However, the study focuses more particularly on the scale change allowing describing the honeycomb as an equivalent homogeneous media. The analysis is base on the volume averaging theory. A thermal-equilibrium assumption is considered to express a macroscopic one-equation model including all the thermal exchanges. The local contributions to the macroscopic balance equation are taken into account defining closure problems. These closure problems are computed numerically on a periodic representative cell of the filter to obtain an effective thermal conductivity tensor. The particles oxidation reaction is taken into account as a source term in the macroscopic equation. It includes a global reaction kinetic model. The oxygen transport through the soot layer appears to play a limiting role for the chemical reaction. The complete macroscopic energy balance model is solved numerically with a finite volume method. The measurements obtained from two different experimental apparatus are used to validate the approach. Finally, the influence of some geometrical parameters on the thermal behaviour during regeneration is discussed. (author)

  3. Kinetic study of diesel soot oxidation: application to simulation of diesel particulate filter regeneration; Etude cinetique de la combustion des suies diesel: application a la modelisation de la regeneration du filtre a particule

    Huguet, Ch.


    Because of their toxicity, soot are considered as the most important pollutant from Diesel engines. The Diesel Particulate Filter (DPF) is widely deployed in Europe to address the significant reductions in particulate emissions required by increasingly stringent emission standards, both for heavy duty vehicles and passenger cars. Such a DPF filtrates above 99% of soot emissions and must be regularly regenerated. The use of additive allows to decrease the soot oxidation temperature to values which can be reached by appropriate engine tuning. The soot addition is a dominant parameter for the development of regeneration strategies. Its influence must be correctly represented by models. This Ph-D was performed at IFP in collaboration with ADEME and was supported by the LCSR at Orleans. The aim of the present research is to develop a kinetic mechanism characteristic of Diesel soot oxidation, which can be integrated into a DPF regeneration model and used for engine control. The oxidation study was based on soot characterisation and reaction kinetics investigations. The samples of Diesel soot were collected, without and with Cerium/Iron additive, by using two engines points representative of two normalized European cycles (ECE and EUDC). Thermal and composition analyses with techniques such as XPS, XRD or TEM were used to determine their physical and chemical properties. Their oxidation kinetics was experimentally studied on a synthetic gas bench (SGB) with a fixed bed reactor. Different tests were performed: temperature-programmed oxidation (TPO), Isothermal oxidation (IO), and sequential oxidation. The results allowed to correlate Diesel soot physical and chemical properties with their oxidation rate. A kinetic model was developed, which is based on global carbon consummation law and distinguishes the oxidation of different soot components. The simulation results agree very well with the experimental results of Diesel soot oxidation. (author)

  4. Multi scale study of the plasticity at low temperature in {alpha}-iron: application for the cleavage; Etude multiechelle de la plasticite du fer-{alpha} a basse temperature application au clivage

    Chaussidon, J


    An accident inside a nuclear power plant may lead to the cleavage of the nuclear vessel made of bainitic steel. In order to understand the origin of this fracture, we studied BCC-iron plasticity at low temperature using numerical simulations at different scales. Molecular Dynamics simulations show the high dependency of screw dislocation motion with temperature and stress. Results from these simulations were added to experiment data to develop a new Dislocation Dynamics code dedicated to BCC iron at low temperature. The code was used to model plasticity into a ferritic lath for various temperatures. This work confirms that cleavage is favoured by low temperatures. (author)

  5. Novel diagnostics for warm dense matter: application to shock compressed target; Nouveaux diagnostics pour l'etude de la matiere dense et chaude: application aux cibles comprimees par choc laser

    Ravasio, A


    In this work, we present 3 novel diagnostics for warm dense plasma (WDM) investigations: hard X-ray radiography, proton radiography and X-ray Thomson scattering. Each of these techniques is applied in shock compression experiments. The main objective consists in accessing a new parameter, in addition to shock and particle velocity, for EOS (Equation of State) measurements. In the first chapter we give a deep description of WDM states as strongly coupled and Fermi degenerate states. Then, we introduce how we have generated a WDM state in our experiment: the shock wave. We, in particular, illustrate its formation in the classical laser-matter interaction regime. In the second chapter the principles of standard probing techniques are presented. We see that energetic probe sources are necessary to investigate high Z dense plasmas. The third chapter is dedicated to X-ray radiography results. We report on a first direct density measurement of a shock compressed high Z target using K{alpha} hard X-ray radiation. These results are of great interests as they allow an in-situ characterization of high Z material, impossible with standard techniques. We show that probing a well known material as Al will allow the comparison between our data and the results from already validated simulations. In the fourth chapter, we present the results obtained from proton radiography on low density carbon foam. The data analysis will require the development of a specific Monte-Carlo code to simulate the proton propagation through the shocked target. The comparison of the simulations with the experimental data show a low dependency on density. The fifth chapter is devoted to X-ray Thomson scattering results. For the first time, we have performed collective x-ray Thomson scattering measurement from a shock compressed target, accessing to electron density and temperature. The obtained results are compared with simulated x-ray scattered spectra. The novel technique is then used in the investigation of less characterised materials (LiH samples). In addition, from the obtained data, we will be able to evidence the effects of strong coupled ion dynamics in dense plasmas.

  6. Uncertainty representation and combination: new results with application to nuclear safety issues; Representation et combinaison d'informations incertaines: nouveaux resultats avec applications aux etudes de surete nucleaires

    Destercke, S.


    It often happens that the value of some parameters or variables of a system are imperfectly known, either because of the variability of the modelled phenomena, or because the available information is imprecise or incomplete. Classical probability theory is usually used to treat these uncertainties. However, recent years have witnessed the appearance of arguments pointing to the conclusion that classical probabilities are inadequate to handle imprecise or incomplete information. Other frameworks have thus been proposed to address this problem: the three main are probability sets, random sets and possibility theory. There are many open questions concerning uncertainty treatment within these frameworks. More precisely, it is necessary to build bridges between these three frameworks to advance toward a unified handling of uncertainty. Also, there is a need of practical methods to treat information, as using these frameworks can be computationally costly. In this work, we propose some answers to these two needs for a set of commonly encountered problems. In particular, we focus on the problems of: 1) Uncertainty representation 2) Fusion and evaluation of multiple source information 3) Independence modelling, the aim being to give tools (both of theoretical and practical nature) to treat uncertainty. Some tools are then applied to some problems related to nuclear safety issues. (author)

  7. Application of the Gaussian beam summation method to the study of the ultrasonic wave propagation in a turbulent medium; Application de la methode de sommation de faisceaux gaussiens a l`etude de la propagation ultrasonore en milieu turbulent

    Fiorina, D


    Some systems for the control and the surveillance of fast reactors are based on the characteristics of the ultrasonic wave propagation. We present here the results of a numerical and experimental study of ultrasonic propagation in a thermal turbulent medium. A numerical model, based on the technique of superposition of discrete Fourier modes for representing isotropic and homogeneous turbulence and on the Gaussian beam summation method for calculating the acoustic field, has been implemented in order to study the propagation of a point source wave in a bidimensional turbulent medium. Our model is based on the following principle: the medium is represented by a great number of independent realizations of a turbulent field and for each of them we calculate the acoustic field in a deterministic way. Statistics over a great number of realizations enable us to access to the different quantities of the distorted acoustic field: variance of the time of flight fluctuations, scintillation index and intensity probability density function. In the case of small fluctuations, the results for these three quantities are in a good agreement with analytical solutions. When the level of the fluctuations grows, the model predicts correct evolutions. However, a great sensitivity to the location of a receiver in the vicinity of a caustic has been proved. Calculations in the temporal domain have also been performed. They give an illustration of the possible effects of the turbulence on an impulsion signal. An experimental device, fitted with thermocouples and acoustic transducers, has been used to study the ultrasonic propagation in turbulent water. The different measures permitted to characterize the turbulent field and to get aware of the effect of the turbulence on the acoustic propagation. The acoustical measures agree well with the analytical solution of Chernov and Rytov. They are show the importance of the knowledge of the real spectrum of the fluctuations and the limitations of the Gaussian correlation function. At last, we have studied the de-focalization of an antenna by a turbulent field. (authors) 71 refs.

  8. A study of the wall/jet interaction on a transient spray. Application to diesel injection; Etude de l'interaction jet/paroi dans un spray transitoire. Application a l'injection diesel

    Chale Gongora, H.G.


    The aim of this work is to better understand the mechanisms that govern the formation and development of the parietal flow occurring during the impact of a diesel fuel jet on a plate. In order to isolate the dynamical aspects of the phenomenon, a non-confined experimental configuration at ambient temperature and pressure has been used. The behaviour of the dispersed phase for different conditions of jet approach and different plate temperatures has been analyzed. Velocity and diameter fields of the free zone and of the parietal zone have been measured using a laser doppler apparatus up to a plate surface resolution of 0.2 mm. In a first step, an estimation of the average time value gives information about the global behaviour of the spray: the plate effect is sensible up to a very reduced distance but increases with the plate temperature, the momentum of the parietal jet is localized in a zone very close to the wall, an increase of the droplets size and of radial velocities in the parietal zone is observed when the nozzle is moved closer to the wall, and the increase of the plate temperature facilitates the jet penetration and leads to a reduction of the droplets size (increase of the shear stresses) and to a reduction of the liquid film thickness submitted to splashing. In order to examine the behaviour of velocity and droplets diameter with time, a processing has been defined which provides an average description of the phenomena. A laser tomography study in association with fast cinematography and CCD camera video recording has permitted to outline the main aspects of the evolution of the parietal spray with time: fast development of a swirl which drags most of the small droplets and limits their dispersion, effect of the temperature rise of the plate in the beginning of fuel injection, development of a more intense swirl which leads to an increase of velocity fluctuations, development of wavelet structures in the internal zone of the flow, near the wall, and from which the liquid film develops. (J.S.)

  9. TEM and EELS study of deuterated carbon: application to the fuel retention in tokamaks; Etude couplee MET-EELS du carbone deutere: application a la retention du combustible dans les tokamaks

    Bernier, N


    We developed a methodology, based on the combination of TEM and EELS techniques, for a structural and chemical characterization, at a high spatial resolution, of a wide range of carbon materials. We i) optimized, in the framework of theoretical models, the sp2 fraction quantification from pure carbons by EELS ii) transferred this quantification to deuterated amorphous carbon layers iii) showed, from graphitized carbons, how the TEM-EELS combination allows to detect low concentrations of implanted D. Due to the accomplishment of these developments, we applied our approach to the study of D retention in composites C/C, which are the plasma-facing materials in TS. We showed that specific localized retention sites correspond to relatively large ({approx} 3 mm.) cracks between fibres and matrix; such cracks offer a simple and direct path for deuterated amorphous carbon. The particle balance performed in TS is discussed in the light of this trapping mechanism. (author)

  10. Corrosion and cathodic protection of buried pipes: study, simulation and application of solar energy; Corrosion et protection cathodique des canalisations enterrees: etude, simulation et application de l energie solaire

    Laoun, Brahim; Serir, Lazhar [Unite de Recherche Appliquee en Energies Renouvelables, URAER / Zone Industrielle Gaar Taam B.P. 88 - 47001, Ghardaia, (Algeria); Niboucha, Karima [Centre de Recherche Scientifique et Technique en Soudage et Controle, CSC / Route de Dely Brahim B.P. 64 - 16000, Cheraga, Alger, (Algeria)


    Cathodic protection is intensively used on steel pipes in petroleum and gas industries. It is a technique used to prevent corrosion which transforms the whole pipe into a cathode of a corrosion cell. Two types of cathodic protection systems are usually used: 1) the galvanic protection systems which use galvanic anodes, also called sacrificial anodes being electrochemically more electronegative than the structure to be protected and 2) the imposed current systems, which through a current generator will deliver a direct current from the anode to the structure to be protected. The aim of this work is to design a cathodic protection system of a pipe by imposed current with auxiliary electric solar energy. (O.M.)

  11. Study of stochastic approaches of the n-bodies problem: application to the nuclear fragmentation; Etude des approches stochastiques du probleme a N corps: application a la multifragmentation nucleaire

    Guarnera, A.


    In the last decade nuclear physics research has found, with the observation of phenomena such as multifragmentation or vaporization, the possibility to get a deeper insight into the nuclear matter phase diagram. For example, a spinodal decomposition scenario has been proposed to explain the multifragmentation: because of the initial compression, the system may enter a region, the spinodal zone, in which the nuclear matter is no longer stable, and so any fluctuation leads to the formation of fragments. This thesis deals with spinodal decomposition within the theoretical framework of stochastic mean filed approaches, in which the one-body density function may experience a stochastic evolution. We have shown that these approaches are able to describe phenomena, such as first order phase transitions, in which fluctuations and many-body correlations plan an important role. In the framework of stochastic mean-filed approaches we have shown that the fragment production by spinodal decomposition is characterized by typical time scales of the order of 100 fm/c and by typical size scales around the Neon mass. We have also shown that these features are robust and that they are not affected significantly by a possible expansion of the system or by the finite size of nuclei. We have proposed as a signature of the spinodal decomposition some typical partition of the largest fragments. The study and the comparison with experimental data, performed for the reactions Xe + Cu at 45 MeV/A and Xe + Sn at 50 MeV/A, have shown a remarkable agreement. Moreover we would like to stress that the theory does not contain any adjustable parameter. These results seem to give a strong indication of the possibility to observe a spinodal decomposition of nuclei. (author).

  12. Clinical aspects and potential clinical applications of laser accelerated proton beams

    Spatola, C.; Privitera, G.


    Proton beam radiation therapy (PBRT), as well as the other forms of hadrontherapy, is in use in the treatment of neoplastic diseases, to realize a high selective irradiation with maximum sparing of surrounding organs. The main characteristic of such a particles is to have an increased radiobiological effectiveness compared to conventional photons (about 10% more) and the advantage to deposit the energy in a defined space through the tissues (Bragg peak phenomenon). The goal of ELIMED Project is the realization of a laser accelerated proton beam line to prove its potential use for clinical application in the field of hadrontherapy. To date, there are several potential clinical applications of PBRT, some of which have become the treatment of choice for a specific tumour, for others it is under investigation as a therapeutic alternative to conventional X-ray radiotherapy, to increase the dose to the tumour and reduce the side effects. For almost half of cancers, an increased local tumour control is the mainstay for increased cancer curability.

  13. Medical research and multidisciplinary applications with laser-accelerated beams: the ELIMED netwotk at ELI-Beamlines

    Tramontana, A.; Anzalone, A.; Candiano, G.; Carpinelli, M.; Cirrone, G. A. P.; Cuttone, G.; Korn, G.; Licciardello, T.; Maggiore, M.; Manti, L.; Margarone, D.; Musumarra, A.; Perozziello, F.; Pisciotta, P.; Raffaele, L.; Romano, F.; Romano, F. P.; Stancampiano, C.; Schillaci, F.; Scuderi, V.; Torrisi, L.; Tudisco, S.


    Laser accelerated proton beams represent nowadays an attractive alternative to the conventional ones and they have been proposed in different research fields. In particular, the interest has been focused in the possibility of replacing conventional accelerating machines with laser-based accelerators in order to develop a new concept of hadrontherapy facilities, which could result more compact and less expensive. With this background the ELIMED (ELIMED: ELI-Beamlines MEDical applications) research project has been launched by LNS-INFN researchers (Laboratori Nazionali del Sud-Istituto Nazionale di Fisica Nucleare, Catania, IT) and ASCR-FZU researchers (Academy of Sciences of the Czech Republic-Fyzikální ústar, Prague, Cz), within the pan-European ELI-Beamlines facility framework. Its main purposes are the demonstration of future applications in hadrontherapy of optically accelerated protons and the realization of a laser-accelerated ion transport beamline for multidisciplinary applications. Several challenges, starting from laser-target interaction and beam transport development, up to dosimetric and radiobiological issues, need to be overcome in order to reach the final goals. The design and the realization of a preliminary beam handling and dosimetric system and of an advanced spectrometer for high energy (multi-MeV) laser-accelerated ion beams will be shortly presented in this work.

  14. Design of the fuel element 'snow-flake' in uranium oxide, canned with aluminium, for the experimental reactor EL 3 (1960); Etude d'un element combustible en oxyde d'uranium gaine d'aluminium, type ''cristal de neige'' pour la pile EL 3 (1960)

    Gauthron, M.; Guibert, B. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires


    This report sums up the main studies have been carried out on the fuel element 'Snowflake' (uranium oxide, canned with aluminium), designed to replace the present element of the experimental reactor EL3 in order to increase the reactivity without modifying the neutron flux/thermal power ratio. (author) [French] Ce rapport resume les principales etudes qui ont ete faites sur l'element combustible 'Cristal de Neige' (a oxyde d'uranium, gaine d'aluminium) destine a remnlacer l'element actuel du reacteur experimental EL3, afin d'en augmenter la reactivite sans modifier le rapport flux neutronique-puissance thermique. (auteur)

  15. Report by the AERES on the unit: Reactor Study Department (DER) under the supervision of the establishments and bodies: Atomic Energy and Alternative Energies Commission (CEA); Rapport de l'AERES sur l'unite: Departement d'Etudes des Reacteurs (DER) sous tutelle des etablissements et organismes: CEA



    This report is a kind of audit report on a research laboratory, the DER (Departement d'Etudes des Reacteurs, Reactor Study Department) whose activity if focused on four main themes: neutron transport simulation in reactor cores, thermal-hydraulic simulation of reactors, design and safety of innovative reactors, nuclear instrumentation for reactors. The authors discuss an assessment of the whole unit activities in terms of strengths and opportunities, aspects to be improved, risks and recommendations, productions and publications, scientific quality, influence and attractiveness (awards, recruitment capacity, capacity to obtain financing and to tender, participation to international programs), strategy and governance, and project. These same aspects are then discussed and commented for each theme

  16. Research Essay for the Goldwater Scholarship Application

    Davison, Jacob August [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    Oxygen is found in many natural and human-made structures and materials, including water, concrete, or any oxide. The severe lack of data on the cross section of 16O(n,α), a reaction that can be found in any material containing oxygen, is detrimental to a complete understanding of the natural or induced behavior of these materials [HYL16]. Additionally, study of this particular reaction and other neutron-induced reactions involving oxygen are useful in the design of naval light water reactors and applications in radio-biology [HYL16]. A detailed understanding of the 16O(n,α) reaction is vital to the safe and efficient study, design, and development of applications such as these. My consequent work at the Los Alamos National Laboratory (LANL), under the supervision of my mentor, Dr. Hye Young Lee, concerned an experiment to measure the reaction rate of 16O(n,α) with unprecedented precision, using a method of experimentation known as the ”forward propagating approach.” What separates this method from traditional experimentation is in the use of computer simulations; in essence, this method entails the development of a computer-simulated experimental environment that behaves similarly to a corresponding physical experimental environment (the word ”similar” is used here to convey an equivalence in properties of materials, like geometry or density, and characteristics of certain nuclear processes between the simulated and physical environments). The simulated environment receives inputs, like detector resolution and efficiency, beam resolution, or theoretical calculations of cross sections, that are determined from physically measured results, and then output data that – provided the simulation was prepared and executed properly – closely resemble the results expected from physical execution of the experiment. By comparing data from the simulated experiment and the physical experiment, the relevant results can be

  17. Recommendations from gynaecological (GYN) GEC ESTRO working group (II): concepts and terms in 3D image-based treatment planning in cervix cancer brachytherapy-3D dose volume parameters and aspects of 3D image-based anatomy, radiation physics, radiobiology.

    Pötter, Richard; Haie-Meder, Christine; Van Limbergen, Erik; Barillot, Isabelle; De Brabandere, Marisol; Dimopoulos, Johannes; Dumas, Isabelle; Erickson, Beth; Lang, Stefan; Nulens, An; Petrow, Peter; Rownd, Jason; Kirisits, Christian


    The second part of the GYN GEC ESTRO working group recommendations is focused on 3D dose-volume parameters for brachytherapy of cervical carcinoma. Methods and parameters have been developed and validated from dosimetric, imaging and clinical experience from different institutions (University of Vienna, IGR Paris, University of Leuven). Cumulative dose volume histograms (DVH) are recommended for evaluation of the complex dose heterogeneity. DVH parameters for GTV, HR CTV and IR CTV are the minimum dose delivered to 90 and 100% of the respective volume: D90, D100. The volume, which is enclosed by 150 or 200% of the prescribed dose (V150, V200), is recommended for overall assessment of high dose volumes. V100 is recommended for quality assessment only within a given treatment schedule. For Organs at Risk (OAR) the minimum dose in the most irradiated tissue volume is recommended for reporting: 0.1, 1, and 2 cm3; optional 5 and 10 cm3. Underlying assumptions are: full dose of external beam therapy in the volume of interest, identical location during fractionated brachytherapy, contiguous volumes and contouring of organ walls for >2 cm3. Dose values are reported as absorbed dose and also taking into account different dose rates. The linear-quadratic radiobiological model-equivalent dose (EQD2)-is applied for brachytherapy and is also used for calculating dose from external beam therapy. This formalism allows systematic assessment within one patient, one centre and comparison between different centres with analysis of dose volume relations for GTV, CTV, and OAR. Recommendations for the transition period from traditional to 3D image-based cervix cancer brachytherapy are formulated. Supplementary data (available in the electronic version of this paper) deals with aspects of 3D imaging, radiation physics, radiation biology, dose at reference points and dimensions and volumes for the GTV and CTV (adding to [Haie-Meder C, Pötter R, Van Limbergen E et al. Recommendations from

  18. Effect of high energy electrons on the skin and on the underlying tissues of the rabbit. A clinical and histological study; Effets des electrons de haute energie sur la peau et les tissus sous-jacents du lapin. Etude clinique et histologique

    Legeay, G.; Vialettes, H.; Adnet, J.J.; Court, L.; Masse, R. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires


    The authors consider in this report the effects of high-energy electrons on rabbit teguments and on the underlying tissues after a single high dose irradiation. After briefly considering the mechanism of interaction between the electrons and matter as a function of their energy, the authors describe the dosimetry carried out, as a function of the irradiation device. The animal received surface doses of 5700 to 22100 rads in the thigh; the electron energy varied from 21 to 30 MeV. A clinical study was carried out over a period of nine months with a view to following the evolution of the damage and the functional degradation of the underlying tissues. A histological study of the induced damage was made after a second irradiation using 30 MeV electrons to produce doses of 16400 rads. Interesting observations were made concerning the damage caused to muscular and nerve tissues. (authors) [French] Les auteurs etudient, dans ce rapport, les effets des electrons de haute energie sur les teguments du lapin et les tissus sous-jacents apres une irradiation unique a dose elevee. Apres un rappel du mecanisme de l'interaction des electrons avec la matiere en fonction de leur energie, la dosimetrie realisee est exposee en fonction du dispositif d'irradiation. Les animaux ont recu, au niveau de la cuisse, des doses en surface de 5700 a 22100 rads; les energies des electrons vont de 21 a 30 MeV. Une etude clinique des lesions, observees pendant 9 mois, decrit leur evolution ainsi que les alterations fonctionnelles des tissus sous-jacents. Une etude histologique des lesions induites a ete realisee au cours d'une seconde experience pour des doses de 16400 rads avec des electrons de 30 MeV. D'interessantes observations ont ete faites concernant les lesions des tissus musculaires et nerveux. (auteurs)

  19. Contribution to research on the metabolism of fission product. Studies on the physico-chemical state and the metabolic fate of radio-cerium solution; Contribution a l'etude du metabolisme des produits de fission. Recherches sur l'etat physico-chimique et le devenir metabolique des solutions de radiocerium

    Aeberhardt, A. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    This paper describes a study of the physico-chemical state of radio-cerium in dilute solutions on the tracer scale, as a function of the pH of the solution. The way in which this radioelement is transported in the blood is studied in vitro and in vivo, with reference to the ionic or colloidal state of the radio-cerium used. The distribution of cerium amongst the various components of the blood is studied by a new method of blood fractionation and by paper electrophoresis. Evidence of a cerium globulin connection is shown in the case of ionic cerium. A study of the initial distribution of radio-cerium in rats, after intravenous administration of ionic or colloidal solutions, shows considerable differences according to the physico-chemical state of the cerium injected. (author) [French] Ce travail presente une etude de l'etat physico-chimique du radiocerium en solutions diluees a l'echelle des indicateurs, en fonction du pH de la solution. En fonction de l'etat ionique ou colloidal du radiocerium utilise, le mode de transport de ce radioelement dans le sang est etudie in vitro et in vivo. La distribution du cerium entre les differents constituants du sang est etudiee par une methode nouvelle de fractionnement du sang et par electrophorese sur papier. L'existence d'une liaison cerium-globuline est mise en evidence dans le cas du cerium ionique. L'etude de la distribution initiale du radiocerium, chez le rat apres administration par voie veineuse de solutions ionique ou colloidale, montre des differences importantes en fonction de l'etat physico-chimique du cerium injecte. (auteur)

  20. Application of paper chromatography to the determination of some elements in minerals and rocks; Application de la chromatographie sur papier a la determination de certains elements dans les mineraux et les roches

    Agrinier, H. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires


    This publication describes our work in applying paper chromatography to the fields of mineralogy and geology. We have studied the separation and determination of the following elements: Nb, Ta, Ti, Co, Cu, Mn, Sn, Ge, As, Sb, Bi, U, Th, Be, Au, Pb, Zn, V and Mo. The development of separation methods for these various elements has led us to solve many interference problems. These methods make it possible to separate and measure mineral components. They also enable us to search for trace elements in ores, rocks soils and carbonaceous materials. Finally let us point out that this technique may equally be used for analysis in very radioactive environment. (author) [French] Dans cette etude, nous etendons le champ d'application de la chromatographie sur papier aux domaines de la mineralogie et de la geologie. Nous avons etudie la separation et la determination des elements suivants: Nb, Ta, Ti, Co, Cu, Mn, Sn, Ge, As, Sb, Bi, U, Th, Be, Au, Pb, Zn, V et Mo. La mise au point des methodes de separation concernant ces differents elements nous a amenes a resoudre de nombreux problemes d'interference. Ces methodes permettent la separation et le dosage des constituants des mineraux, ainsi que la recherche d'elements en traces dans les minerais, les roches, les sols et les materiaux carbonnes. Signalons pour terminer que cette technique peut egalement trouver son utilisation dans le domaine de l'analyse en milieu tres radio-actif. (auteur)

  1. Contribution to thermodynamics and kinetics of argon, krypton and xenon at very low temperatures; Contribution a l'etude thermodynamique et cinetique de l'argon, du krypton et du xenon aux tres basses temperatures

    Levenson, L.L. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    A critical analysis of the main theories of condensation, which are due to Zwanzig, Cabrera, Mc Caroll and Ehrlich, Wanlass, Armand, and Yu and Soo, is made. A condensation coefficient equal to unity is expected from these theories, except Armand and Yu and Soo, when the temperature of the gas impinging on its own solid phase is equal or less than 300 K. Using a resonating quartz microbalance the sensitivity of which is 10{sup -9} g. cm{sup 2} the e