WorldWideScience

Sample records for cellular radiobiological action

  1. Radiobiology

    International Nuclear Information System (INIS)

    This text-book (electronic book - multi-media CD-ROM) constitutes a course-book - author's collection of lectures. It consists of 13 lectures in which the reader acquaints with the basis of radiobiology: Introduction to radiobiology; Physical fundamentals of radiobiology; Radiation of cells; Modification of radiation damage of cells; Reparation of radiation damage of cells; Radiation syndromes and their modification; Radiation injury; Radiation damage of tissues; Effect of radiation on embryo and fetus; Biological effects of incorporated radionuclides; Therapy of acute irradiation sickness; Delayed consequences of irradiation; Radiation oncology and radiotherapy. This course-book may be interesting for students, post-graduate students of chemistry, biology, physics, medicine as well as for teachers, scientific workers and physicians. (author)

  2. Direct relationship between radiobiological hypoxia in tumors and monoclonal antibody detection of EF5 cellular adducts.

    Science.gov (United States)

    Lee, J; Siemann, D W; Koch, C J; Lord, E M

    1996-07-29

    While the potential importance of hypoxia in limiting the sensitivity of tumor cells to ionizing radiation has long been appreciated, methods for accurately quantifying the number of radiation-resistant hypoxic cells within tumors have been lacking. We have used the pentafluorinated derivative [2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl)-acet amide] of etanidazole (EF5), which binds selectively to hypoxic cells. The adducts formed between EF5 and cellular proteins in the hypoxic cells were detected using the specific monoclonal antibody (MAb), ELK3-51 conjugated to the flurochrome Cy3, and the number of hypoxic cells was quantified by flow cytometry. To verify the validity of this technique for the detection of hypoxic cells, mice bearing KHT sarcomas were treated with various agents to alter tumor oxygenation and hence vary the fraction of radiobiologically hypoxic tumor cells. The percentage of EF5 binding cells was then compared directly with the clonogenic survival of the tumor cells following radiation treatment under the various pretreatment conditions. The results showed that allowing the mice to breathe carbogen (5% CO2/95% O2) prior to irradiation reduced clonogenic cell survival approx. 6-fold and led to an absence of cells binding high levels of EF5. In contrast, pretreating the tumor-bearing animals with either hydralazine, which decreased tumor blood flow, or phenylhydrazine hydrochloride, which made the mice anemic, increased tumor cell survival following irradiation 2- to 4-fold, indicative of an increase in the fraction of hypoxic tumor cells. EF5 measurements made under identical conditions illustrated a shift in the cells in the tumor to high EF5 binding. Our results demonstrate that flow cytometric measurement by fluorescent MAb binding to EF5 adducts may relate directly to radiobiological hypoxia in KHT tumors measured by conventional methods. PMID:8707411

  3. Physical and cellular radiobiological properties of heavy ions in relation to cancer therapy applications

    International Nuclear Information System (INIS)

    A variety of experiments have been carried out in vitro on several mammalian cell lines with carbon, neon, silicon and argon beams at 14 and 24 cm depth penetration. The results of these experiments substantiate the conceptual basis for physical and radiobiological advantages of accelerated heavy-ion beams in cancer therapy. The best biologically effective depth dose ratio for situations corresponding to therapy needs can be obtained with accelerated carbon beams. The depression of the oxygen effect with silicon or argon ion beams is greater than that achievable with neutrons or pions, or with heavy ions of lower atomic number

  4. Basic radiobiology

    International Nuclear Information System (INIS)

    Radiobiology, a branch of science concerned with the action of ionizing radiation on biological tissues and living organisms, is a combination of two disciplines: radiation physics and biology. For use in radiobiology and radiation protection the physical quantity that is useful for defining the quality of an ionizing radiation beam is the linear energy transfer (LET). In contrast to the stopping power, which focuses attention on the energy loss by an energetic charged particle moving through a medium, the LET focuses attention on the linear rate of energy absorption by the absorbing medium as the charged particle traverses the medium. When cells are exposed to ionizing radiation the standard physical effects between radiation and the atoms or molecules of the cells occur first and the possible biological damage to cell functions follows later. The biological effects of radiation result mainly from damage to the DNA, which is the most critical target within the cell; however, there are also other sites in the cell that, when damaged, may lead to cell death

  5. Oxidative stress action in cellular aging

    OpenAIRE

    Monique Cristine de Oliveira; João Paulo Ferreira Schoffen

    2010-01-01

    Various theories try to explain the biological aging by changing the functions and structure of organic systems and cells. During lifetime, free radicals in the oxidative stress lead to lipid peroxidation of cellular membranes, homeostasis imbalance, chemical residues formation, gene mutations in DNA, dysfunction of certain organelles, and the arise of diseases due to cell death and/or injury. This review describes the action of oxidative stress in the cells aging process, emphasizing the fac...

  6. Radiobiological Research in JINR

    CERN Document Server

    Krasavin, E A

    2000-01-01

    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. Oxidative stress action in cellular aging

    Directory of Open Access Journals (Sweden)

    Monique Cristine de Oliveira

    2010-12-01

    Full Text Available Various theories try to explain the biological aging by changing the functions and structure of organic systems and cells. During lifetime, free radicals in the oxidative stress lead to lipid peroxidation of cellular membranes, homeostasis imbalance, chemical residues formation, gene mutations in DNA, dysfunction of certain organelles, and the arise of diseases due to cell death and/or injury. This review describes the action of oxidative stress in the cells aging process, emphasizing the factors such as cellular oxidative damage, its consequences and the main protective measures taken to prevent or delay this process. Tests with antioxidants: vitamins A, E and C, flavonoids, carotenoids and minerals, the practice of caloric restriction and physical exercise, seeking the beneficial effects on human health, increasing longevity, reducing the level of oxidative stress, slowing the cellular senescence and origin of certain diseases, are discussed.Diferentes teorias tentam explicar o envelhecimento biológico através da alteração das funções e estrutura dos sistemas orgânicos e células. Ao longo da vida, os radicais livres presentes no estresse oxidativo conduzem à peroxidação dos lipídios das membranas celulares, desequilíbrio da homeostase, formação de resíduos químicos, mutações gênicas no DNA, disfunção de certas organelas, bem como ao surgimento de doenças devido à lesão e/ou morte celular. Nesta revisão descreve-se a ação do estresse oxidativo no processo de envelhecimento das células, enfatizando fatores como os danos oxidativos celulares, suas conseqüências e as principais medidas protetoras adotadas para se prevenir ou retardar este processo. Testes com antioxidantes: vitaminas A, E e C, flavonóides, carotenóides e minerais; a prática de restrição calórica e exercícios físicos, que buscam efeitos benéficos sobre a saúde humana, aumentando a longevidade, reduzindo o nível de estresse oxidativo

  8. Radiobiological aspects of application of interleucine as agents for the first aid under strong radiation action

    International Nuclear Information System (INIS)

    The paper substantiates the application of the interleucine-1 beta (IL-1) as an emergency medical care agent in case of the acute emergency exposure of a human being. During simulation experiments a human recombinant IL-1 was added to suspension of the affected bony marrow-cells extracted a few minutes following the total 5 Gy exposure of Fi male-mice (CBAxC57B1). Recombinant mouse IL-3 and GM-CSF agents (produced by Bering company, Germany) were used for comparison purpose (agent concentration constituted 100-10000 unit/ml). The incubated bony marrow cells were tested for trunk potencies in mice-recipients irradiated by 8.5 Gy dose during 24 h. Following nine days the colonies in their spleen and bony marrow cellular texture were estimated. IL-1 was shown to have the protective effect both on separated trunk type hemopoietic cells and on the whole body irradiated hemopoietic system. IL-1 turned to be similar to radiation-protective agents of polysaccharide nature and to radiation-protective EIR procedure. It is pointed out that IL-1 has no whole body toxic or any other by effects

  9. Microirradiation techniques in radiobiological research

    Indian Academy of Sciences (India)

    Guido A Drexler; Miguel J Ruiz-Gómez

    2015-09-01

    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.

  10. Radiobiology and radiation protection. Recent developments and future trends in radiobiology

    International Nuclear Information System (INIS)

    The 28th annual meeting of the Fachverband fuer Strahlenschutz, held from October 23 - 25, 1996 in Hannover, discussed the various aspects of the leading theme, radiation protection and radiobiology, recent developments and future trends in radiobiology. The papers presented in the proceedings volume address the three main aspects: (1) Mechanisms of the radiation effects - molecular and cellular mechanisms, genetic and prenatal radiation effects, cancerogenesis and mutagenesis; (2) Novel methods in radiobiology research: microdosimetry from the biological angle, novel methods in molecular biology including computerized simulation of DNA, methods of biological dosimetry, radiobiological aspects of neutrons and other densely ionizing radiation (Pt, Rn); (3) Knowledge and concepts for radiological protection: individual radiosensitivity, radiobiological aspects in medical applications of ionizing radiation, accidents in industry, radiation exposure in aeronautics and astronautics. (vhe)

  11. Radiation Protection Research: Radiobiology

    Energy Technology Data Exchange (ETDEWEB)

    Desaintes, C

    2000-07-01

    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.

  12. Geometric domains in cellular radiobiology

    International Nuclear Information System (INIS)

    A joint consideration of experimental findings and microdosimetric facts leads to the conclusion that the biological effects of ionizing radiations are determined by local concentration of absorbed energy at two types of sites that differ greatly in magnitude. They are of the scale of nanometres in primary DNA damage, and of micrometres in the especially deleterious combinations of damaged DNA fragments. Both kinds depend on LET; however, at the nanometre level the dependence is much smaller. Depending on the relative contribution of the two types, the RBE values for observed biological effects can vary considerably but they may be assumed to be larger for cell transformation than for cell killing. (author)

  13. Experimental radiotherapy and clinical radiobiology. Vol. 20. Proceedings

    International Nuclear Information System (INIS)

    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.

  14. Radiobiology and Epidemiology

    International Nuclear Information System (INIS)

    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

  15. Radiobiology and Epidemiology

    Energy Technology Data Exchange (ETDEWEB)

    Desaintes, C; Holmstock, L

    2001-04-01

    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.

  16. DOE/CEC [Department of Energy/Commission of the European Communities] workshop on critical evaluation of radiobiological data to biophysical modeling

    International Nuclear Information System (INIS)

    The Department of Energy's Office of Health and Environmental Research and the Commission of the European Communities (CEC) Radiation Protection Program support the majority of Research in the Field of Radiobiological Modeling. This field of science develops models based on scientifically sound principles to predict biological response (at the cellular, molecular, and animal level) to exposure to low level ionizing radiation. Biophysical models are an important tool for estimating response of ionizing radiation at low doses and dose rates. Generally speaking, the biophysical models can be classified into two groups: (1) mechanistic models and (2) phenomenological models. Mechanistic models are based on some assumptions about the physical, chemical, or biological mechanisms of action in association with radiobiological data whereas the phenomenological models are based solely on available experimental data on radiobiological effects with less emphasis on mechanisms of action. There are a number of these models which are being developed. Since model builders rely on radiobiological data available in the literature either to develop mechanistic or phenomenological models, it is essential that a critical evaluation of existing radiobiological data be made and data that is generally considered good and most appropriate for biophysical modeling be identified. A Workshop jointly sponsored by the DOE and the CEC was held at Oak Ridge, Tennessee from June 23--25, 1988, to review the data available from physical and chemical, cellular and molecular and animal studies with ionizing radiation

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

    International Nuclear Information System (INIS)

    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

  18. Androgens and skeletal muscle: cellular and molecular action mechanisms underlying the anabolic actions.

    Science.gov (United States)

    Dubois, Vanessa; Laurent, Michaël; Boonen, Steven; Vanderschueren, Dirk; Claessens, Frank

    2012-05-01

    Androgens increase both the size and strength of skeletal muscle via diverse mechanisms. The aim of this review is to discuss the different cellular targets of androgens in skeletal muscle as well as the respective androgen actions in these cells leading to changes in proliferation, myogenic differentiation, and protein metabolism. Androgens bind and activate a specific nuclear receptor which will directly affect the transcription of target genes. These genes encode muscle-specific transcription factors, enzymes, structural proteins, as well as microRNAs. In addition, anabolic action of androgens is partly established through crosstalk with other signaling molecules such as Akt, myostatin, IGF-I, and Notch. Finally, androgens may also exert non-genomic effects in muscle by increasing Ca(2+) uptake and modulating kinase activities. In conclusion, the anabolic effect of androgens on skeletal muscle is not only explained by activation of the myocyte androgen receptor but is also the combined result of many genomic and non-genomic actions.

  19. Introduction to radiobiology of targeted radionuclide therapy

    Directory of Open Access Journals (Sweden)

    Jean-Pierre ePOUGET

    2015-03-01

    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

  20. Research in Radiobiology

    International Nuclear Information System (INIS)

    This document contains the tables of contents for the reports published by the University of Utah Radiobiology Laboratory from 1953--1987. Also included is a keyword index for the reports, and references for all books, book and symposia chapters and journal article published by Laboratory staff between 1950 and 1988

  1. With the Radiobiology Group

    CERN Multimedia

    1980-01-01

    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.

  2. Department of Radiobiology - foreword

    International Nuclear Information System (INIS)

    The research program of the Department of Radiobiology of the Niewodniczanski Institute of Nuclear Physics is performed by two laboratories: 1/Laboratory of Neutron Therapy and Applied in Radiobiology Therapy and Agriculture. 2/ Laboratory of Radiation and Environmental Mutagenesis. The aim of the first mentioned Laboratory is to determine the Relative Biological Effectiveness (RBE) of fast 5.6 MeV neutrons with regard to regime of fractionation. Our goal is to reduce the number of fraction of neutron therapy what makes possible increasing the total dose. The second mentioned Laboratory engages in research on the mutagenesis in rape-seed in vitro regeneration of dihaploids and pollen grains. The object is to find how much fast neutrons, X and γ-rays irradiations stimulate the dihaploide production and to determine their reaction in flower buds microspores and anther cultures. (author)

  3. Synthesis, cellular evaluation, and mechanism of action of piperlongumine analogs

    OpenAIRE

    Adams, Drew J.; Dai, Mingji; Pellegrino, Giovanni; Wagner, Bridget K.; Stern, Andrew M.; Shamji, Alykhan F.; Schreiber, Stuart L.

    2012-01-01

    Piperlongumine is a naturally occurring small molecule recently identified to be toxic selectively to cancer cells in vitro and in vivo. This compound was found to elevate cellular levels of reactive oxygen species (ROS) selectively in cancer cell lines. The synthesis of 80 piperlongumine analogs has revealed structural modifications that retain, enhance, and ablate key piperlongumine-associated effects on cells, including elevation of ROS, cancer cell death, and selectivity for cancer cells ...

  4. Action of Selenium Compounds on the Cellular Metabolism by Microcalorimetry

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new method is introduced to study the action between biomaterials and organism.By using an LKB-2277 bioactivity monitor and ampoule method,the fundamental thermogenesis curves of the metabolic process of pk-15 and the toxic effect of three kinds of selenomorpholine compounds on it were studied at 37℃.From the thermogenesis curves,the heat released by pk-15 metabolism was calculated.The results show that the selenium compounds all have toxic action on the metabolism process of pk-15 at the range of experimental concentrations.The sequence of the toxic action of selenium compounds is:Na2SeO3>β-(N-selenomorpholine)-ethyl phenylketone hydrochloride>selenomorpholine.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-01

    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. In vivo tumor radiobiology of heavy charged particles

    International Nuclear Information System (INIS)

    The response of tumor cells systems to irradiation with carbon, neon and argon beams at various positions in the plateau and extended-peak regions of the Bragg ionization curve is being evaluated from experiments conducted both in vivo and in vitro. The radiobiological end points being studied include: tumor volume response, cellular survival after tumor irradiation in situ, and cell-kinetic parameters

  7. A Study of cellular phone possessors' sex consciousness and sex action in high school

    OpenAIRE

    池田, かよ子; 久保田, 美雪; 渡邊, 典子; Ikeda, Kayoko; Kubota, Miyuki; Watanabe, Noriko

    2004-01-01

    The purpose of this survey for 304 high school students (116 boys and 188 girls) is to make sure how high school students who possess cellular phones use their phones, what they use their phones for, to what extent they get information about sex, how far they feel conscious of sex and their sex action. (1) About 60% of the girls have cellular phones, which is larger than the rate of the boys who have cellularphones. (2) As for the frequency of using cellular phones, about 80% of the girls use...

  8. DMPD: Anti-inflammatory actions of PPAR ligands: new insights on cellular andmolecular mechanisms. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17981503 Anti-inflammatory actions of PPAR ligands: new insights on cellular andmol...) (.html) (.csml) Show Anti-inflammatory actions of PPAR ligands: new insights on cellular andmolecular mech...anisms. PubmedID 17981503 Title Anti-inflammatory actions of PPAR ligands: new in

  9. Cellular actions of somatostatin on rat periaqueductal grey neurons in vitro

    OpenAIRE

    Connor, Mark; Bagley, Elena E.; Mitchell, Vanessa A; Ingram, Susan L; Christie, MacDonald J.; Humphrey, Patrick P A; Vaughan, Christopher W

    2004-01-01

    Functional studies indicate that the midbrain periaqueductal grey (PAG) is involved in the analgesic actions of somatostatin; however, the cellular actions of somatostatin in this brain region are unknown. In the present study, whole-cell patch clamp recordings were made from rat PAG neurons in vitro. In 93% of acutely isolated neurons, somatostatin inhibited Ca2+-channel currents. This effect was mimicked by the sst-2 selective agonist BIM-23027, but not by the sst-1 and sst-5 selective agon...

  10. Relevance of cellular to clinical electrophysiology in interpreting antiarrhythmic drug action.

    Science.gov (United States)

    Vaughan Williams, E M

    1989-12-01

    The usefulness of cellular electrophysiologic techniques in elucidating the fundamental actions of antiarrhythmic drugs is contrasted with their apparent lack of relevance to the selection of drugs for the treatment of particular arrhythmias. Clinical electrophysiologists employ different techniques, but their results may be explained in terms of cellular drug actions. The varying clinical effects of class IA, IB and IC agents are due to differences in the speed of their attachment to, and detachment from, sodium channels. The role of sympathetic activity in arrhythmogenesis is complex, but again readily explicable in terms of the electrophysiologic cellular actions of stimulation of the individual types of adrenoceptors (alpha 1, alpha 2, beta 1 and beta 2) and the distribution of these receptors, and of the longterm effects of sympathetic deprivation, either by antisympathetic drugs (class II) or by sympathetic denervation. Delayed repolarization (e.g., by class III drugs or prolonged beta blockade) is antiarrhythmic because it is homogeneous, despite the incidental prolongation of QT. If, however, QT is prolonged by heterogeneity of conduction or repolarization, or by partial sympathetic denervation (long QT syndrome or post myocardial infarction), this indicates increased risk of arrhythmia. Finally, the efficacy of calcium antagonists (class IV) in supraventricular arrhythmias is attributable to the cellular electrophysiologic characteristics of sinoatrial and atrioventricular nodal and transitional elements.

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

    Science.gov (United States)

    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

    2015-12-01

    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.

  12. Investigation of molecular mechanisms in photodynamic action and radiobiology with nanosecond flash photolysis and pulse radiolysis. Progress report, October 1, 1980-September 30, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Grossweiner, L I

    1981-06-01

    Laser flash photolysis experiments have led to a new mechanism for the ultraviolet photolysis of aqueous tryptophan (Trp), indole (Ind) and certain indole derivatives. Excitation at 265 nm leads to photoionization via a pre-fluorescent state with thermal activation. A new formula is proposed for predicting enzyme inactivation quantum yields. The predictions are in good agreement with measurements on six important enzymes at 254 nm and 280 nm. Kinetics models have been developed and tested for important stages in the photosensitization of DNA to near-ultraviolet radiation by furocoumarin compounds currently used for PUVA therapy (psoralen plus UV-A) of psoriasis and other human skin diseases. Experiments on photobinding of psoralen (Ps) and 8-methoxypsoralen (8-MOP) to calf thymus DNA are consistent with the assumption that equilibrium dark complexing of the furocoumarin to the DNA is a precondition for the formation of covalent monoadducts and cross-links. Singlet oxygen generation by furocoumarins has been investigated with liposomes and human erythrocytes (rbc). Results obtained with 3-carbethoxypsoralen (3-CPs), an experimental alternate PUVA sensitizer claimed to be non-tumorigenic, show that 3-CPs interacts with liposome and rbc membranes in the dark. Studies on photosensitization of egg lecithin liposomes by methylene blue (MB) incorporated in the membrane have led to the new result that membrane lysis is a two-stage process. The first stage induced by red light irradiation leads to membrane damage initiated by O/sub 2/*. Membrane lysis takes place in the dark, second stage under the action of mild hydrodynamic stress, such as slow gas bubbling.

  13. Radiobiology software for educational purpose

    International Nuclear Information System (INIS)

    To understand radio-nuclide therapy and the basis of radiation protection, it is essential to understand radiobiology. With limited time for classroom teaching and limited time and resources for radiobiology experiments students do not acquire firm grasp of theoretical mathematical models and experimental knowledge of target theory and Linear quadratic models that explain nature of cell survival curves. We believe that this issue might be addressed with numerical simulation of cell survival curves using mathematical models. Existing classroom teaching can be reoriented to understand the subject using the concept of modeling, simulation and virtual experiments. After completion of the lecture, students can practice with simulation tool at their convenient time. In this study we have developed software that can help the students to acquire firm grasp of theoretical and experimental radiobiology. The software was developed using FreeMat ver 4.0, open source software. Target theory, linear quadratic model, cell killing based on Poisson model have been included. The implementation of the program structure was to display the menu for the user choice to be made and then program flows depending on the users choice. The program executes by typing 'Radiobiology' on the command line interface. Students can investigate the effect of radiation dose on cell, interactively. They can practice to draw the cell survival curve based on the input and output data and they can also compare their handmade graphs with automatically generated graphs by the program. This software is in the early stage of development and will evolve on user feedback. We feel this simulation software will be quite useful for students entering in the nuclear medicine, radiology and radiotherapy disciplines. (author)

  14. Radiotherapy treatment planning linear-quadratic radiobiology

    CERN Document Server

    Chapman, J Donald

    2015-01-01

    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

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

    Institute of Scientific and Technical Information of China (English)

    Hu Zhiwen; Wu Lijun; Yu Zengliang

    2005-01-01

    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.

  16. Characteristics of Middle School Students Learning Actions in Outdoor Mathematical Activities with the Cellular Phone

    Science.gov (United States)

    Daher, Wajeeh; Baya'a, Nimer

    2012-01-01

    Learning in the cellular phone environment enables utilizing the multiple functions of the cellular phone, such as mobility, availability, interactivity, verbal and voice communication, taking pictures or recording audio and video, measuring time and transferring information. These functions together with mathematics-designated cellular phone…

  17. Conjunct action of gamma radiation and casiopeinas in two cellular types

    International Nuclear Information System (INIS)

    In Mexico the cancer occupies the second place in the causes of death and although already there are diverse useful treatments to attack this suffering, the search of new pharmaceuticals that present positive effect in the treatment of the cancer there is taken to the development of a group of substances called Casiopeinas. Its are coordination compounds constituted by a central atom of copper (Cu II) joined to organic ligands, with general condensed formula [Cu (NN)(ON)]NO3, or [Cu(NN)(OO)]NO3. Its present different cytotoxicity levels, as well as in vitro antineoplastic activity in diverse tissues derived of tumors. Even its ignore the mechanisms of it action, but one of them, it could be by generation of reactive species of oxygen (ERO), mediated by the metallic center that contain. Thinking of this possibility was carried out in vitro experiments, exposing lymphocytes or HeLa cells, to ionizing radiation, at two casiopeinas (Casiopeina llgly and the Casiopeina Ill-e-a) or the combination of both agents, in order to determine if the antineoplastic capacity of both types of treatments increase in conjunct action. To determine it its were carried out cytotoxicity tests by means of the differential dyeing of fluorescein diacetate and etidio bromide, in these the cells alive fluorescein in green color while the dead ones only the nucleus of red tinged. The genotoxicity was evaluated by means of the comet essay. The results hurtled that as much the casiopeinas as the radiation by separate don't present difference among both cellular types, probably due to the used method that only quantifies the damages at the moment and not to long term. And according to those treatments on the whole only to the concentrations and the doses more high it favors the additive effect due to an overproduction of free radicals that not can be neutralized. According to the genotoxicity, only proven for the radiation indicates that the HeLa cells presents a major number of cells with

  18. Studies in the radiobiology of osteoradionecrosis and their clinical significance

    Energy Technology Data Exchange (ETDEWEB)

    Marx, R.E.; Johnson, R.P.

    1987-10-01

    The radiobiology of osteoradionecrosis is a complex of cellular death and cellular functional impairments from radiation energy transfers. Four studies of irradiated patients and a data base from 536 patients with osteoradionecrosis revealed separate pathophysiologic conditions for osteoradionecrosis induced by early trauma, osteoradionecrosis induced by late trauma, and spontaneous osteoradionecrosis. A large body of data suggested useful clinical guidelines for the management of irradiated patients. The guidelines, in part, include a recommendation for deferring radiation treatment for 21 days after tissue wounding, if possible; a relative contraindication to wounding tissue during a radiation course; a recommendation for the use of hyperbaric oxygen before wounding; and a strong recommendation to provide comprehensive dental care to the irradiated patient.

  19. Repeatedly administered antidepressant drugs modulate humoral and cellular immune response in mice through action on macrophages.

    Science.gov (United States)

    Nazimek, Katarzyna; Kozlowski, Michael; Bryniarski, Pawel; Strobel, Spencer; Bryk, Agata; Myszka, Michal; Tyszka, Anna; Kuszmiersz, Piotr; Nowakowski, Jaroslaw; Filipczak-Bryniarska, Iwona

    2016-08-01

    Depression is associated with an altered immune response, which could be normalized by antidepressant drugs. However, little is known about the influence of antidepressants on the peripheral immune response and function of macrophages in individuals not suffering from depression. Our studies were aimed at determining the influence of antidepressant drugs on the humoral and cellular immune response in mice. Mice were treated intraperitoneally with imipramine, fluoxetine, venlafaxine, or moclobemide and contact immunized with trinitrophenyl hapten followed by elicitation and measurement of contact sensitivity by ear swelling response. Peritoneal macrophages from drug-treated mice were either pulsed with sheep erythrocytes or conjugated with trinitrophenyl and transferred into naive recipients to induce humoral or contact sensitivity response, respectively. Secretion of reactive oxygen intermediates, nitric oxide, and cytokines by macrophages from drug-treated mice was assessed, respectively, in chemiluminometry, Griess-based colorimetry and enzyme-linked immunosorbent assay, and the expression of macrophage surface markers was analyzed cytometrically. Treatment of mice with fluoxetine, venlafaxine, and moclobemide results in suppression of humoral and cell-mediated immunity with a reduction of the release of macrophage proinflammatory mediators and the expression of antigen-presentation markers. In contrast, treatment with imipramine enhanced the humoral immune response and macrophage secretory activity but slightly suppressed active contact sensitivity. Our studies demonstrated that systemically delivered antidepressant drugs modulate the peripheral humoral and cell-mediated immune responses, mostly through their action on macrophages. Imipramine was rather proinflammatory, whereas other tested drugs expressed immunosuppressive potential. Current observations may be applied to new therapeutic strategies dedicated to various disorders associated with excessive

  20. National Radiobiology Archives distributed access programmer's guide

    International Nuclear Information System (INIS)

    The National Radiobiology Archives is a comprehensive effort to gather, organize, and catalog original data, representative specimens, and supporting materials related to significant radiobiology studies. This provides researchers with information for analyses which compare or combine results of these and other studies and with materials for analysis by advanced molecular biology techniques. This Programmer's Guide document describes the database access software, NRADEMO, and the subset loading script NRADEMO/MAINT/MAINTAIN, which comprise the National Laboratory Archives Distributed Access Package. The guide is intended for use by an experienced database management specialist. It contains information about the physical and logical organization of the software and data files. It also contains printouts of all the scripts and associated batch processing files. It is part of a suite of documents published by the National Radiobiology Archives

  1. Soft x rays for radiobiological studies

    International Nuclear Information System (INIS)

    Lethal effects and chromosome aberrations induced in cells exposed to low energy (soft) X rays demonstrated that these relatively low energy X rays are just as effective as those of higher energy for radiobiological studies, and even more effective for irradiating cultured mammalian cells than laboratory animals. (author)

  2. Radiobiological and clinical aspects of neutron therapy

    International Nuclear Information System (INIS)

    Radiobiological investigations and their interpretation are discussed. The history of neutrontherapy, the results of RBE-investigations in man as well as clinical results are given. The hypothesis on reaction of human tissue and tumours towards neutron irradiation is presented. (A.S.)

  3. National Radiobiology Archives Distributed Access user's manual

    International Nuclear Information System (INIS)

    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

  4. Hypoxic sensitizers: radiobiological studies at the cellular level

    International Nuclear Information System (INIS)

    The nitroimidazoles have been found to selectively sensitize hypoxic cells to the effects of irradiation. The latest in this family of drugs is RO-07-0582, which is able to mimic 80 percent of the oxygen effect at a concentration of 5 mM by modifying the sensitivity of hypoxic cells to single doses of gamma rays; however, it is not a substitution for oxygen in promoting the repair of sublethal radiation damage between split doses. Studies show that it is a powerful cytotoxic agent as well and selectively operates against hypoxic cells. (auth)

  5. Gastric cytoprotection beyond prostaglandins: cellular and molecular mechanisms of gastroprotective and ulcer healing actions of antacids.

    Science.gov (United States)

    Tarnawski, Andrzej; Ahluwalia, Amrita; Jones, Michael K

    2013-01-01

    This article updates current views on gastric mucosal defense, injury, protection and ulcer healing with a focus on mucosal protective and ulcer healing actions of antacids. The gastric mucosa is continuously exposed to a variety of noxious factors, both endogenous such as: 0.1N hydrochloric acid, pepsin, bile acids, lysolecithin, H. pylori toxins and exogenous such as NSAIDs, ethanol and others. Gastric mucosal integrity is maintained by pre-epithelial, epithelial and post-epithelial defense mechanisms permitting the mucosa to withstand exposure to the above damaging factors. When mucosal defense is weakened or overwhelmed by injurious factors, injury develops in the form of erosions or ulcers. In the late 1970s Andre Robert and coworkers discovered that microgram amounts of a prostaglandin E2 analog protects the gastric mucosa against a variety of ulcerogenic and necrotizing agents - even such strong inducers of injury as 100% ethanol and boiling water. They proposed a new concept of cytoprotection. Subsequently, other compounds, such as sulfhydryls, sucralfate and epidermal growth factor were shown to exert protective action on gastric mucosa. Additionally, some antacids have been shown to exert a potent mucosal protective action against a variety of injurious factors and accelerate healing of erosions and gastric ulcers. These actions of antacids, especially hydrotalcite - the newest and the most extensively studied antacid - are due to activation of prostaglandin synthesis; binding to and inactivation of pepsin, bile acids and H. pylori toxins; induction of heat shock proteins; and, activation of genes encoding growth factors and their receptors.

  6. Evaluation of radiobiological effects in 3 distinct biological models

    International Nuclear Information System (INIS)

    Full text of publication follows. The present work aims at sharing the process of development of advanced biological models to study radiobiological effects. Recognizing several known limitations and difficulties of the current monolayer cellular models, as well as the increasing difficulties to use advanced biological models, our group has been developing advanced biological alternative models, namely three-dimensional cell cultures and a less explored animal model (the Zebra fish - Danio rerio - which allows the access to inter-generational data, while characterized by a great genetic homology towards the humans). These 3 models (monolayer cellular model, three-dimensional cell cultures and zebra fish) were externally irradiated with 100 mGy, 500 mGy or 1 Gy. The consequences of that irradiation were studied using cellular and molecular tests. Our previous experimental studies with 100 mGy external gamma irradiation of HepG2 monolayer cells showed a slight increase in the proliferation rate 24 h, 48 h and 72 h post irradiation. These results also pointed into the presence of certain bystander effects 72 h post irradiation, constituting the starting point for the need of a more accurate analysis realized with this work. At this stage, we continue focused on the acute biological effects. Obtained results, namely MTT and clonogenic assays for evaluating cellular metabolic activity and proliferation in the in vitro models, as well as proteomics for the evaluation of in vivo effects will be presented, discussed and explained. Several hypotheses will be presented and defended based on the facts previously demonstrated. This work aims at sharing the actual state and the results already available from this medium-term project, building the proof of the added value on applying these advanced models, while demonstrating the strongest and weakest points from all of them (so allowing the comparison between them and to base the subsequent choice for research groups starting

  7. Workshop on radiobiological effectiveness of neutrons

    International Nuclear Information System (INIS)

    The radiobiological effectiveness (RBE) of neutrons has become the subject of some heated discussions in both scientific and radiation-protection oriented communities. This has become especially so since the realization that neutron exposures of A-bomb survivors in Hiroshima were considerably lower than previously assumed, thus ''devaluating'' the importance of what we thought was a solid human data base. At the same time, more recent data from radiobiological research appeared to indicate that, at least for some biological endpoints, the RBE of neutrons at low doses and low dose rates was increased dramatically compared to the RBE at higher dose and dose rates. As a consequence, the protection of health against neutrons became a subject of some urgency. The objective of this workshop was to evaluate the existing data base in order to determine the need for additional research in this field. 22 refs., 3 figs., 6 tabs

  8. Scientific projection paper for space radiobiological research

    International Nuclear Information System (INIS)

    A nationale for the radiobiological research requirements for space is rooted in a national commitment to the exploration of space, mandated in the form of the National Space Act. This research is almost entirely centered on man; more specifically, on the effects of the space radiation environment on man and his protection from them. The research needs discussed in this presentation include the space radiation environment; dosimetry; radiation biology-high LET particles (dose/response); and operational countermeasures

  9. The Fundamentals of Imaging Physics and Radiobiology

    CERN Document Server

    Selman, Joseph

    2000-01-01

    Like its well-known predecessor, this new and expanded Ninth Edition presents numerous important changes, beginning with the title and continuing throughout the text. Drawing on current knowledge and his own extensive experience, Dr. Selman provides a thorough revision and overview of each previously included chapter. Definitions, foundations, and principles are presented along with changes in methods and procedures. The text presents five new chapters on computed tomography, radioactivity and diagnostic nuclear medicine, radiobiology, protection in radiology/health physics, and nonradiologic

  10. Dosimetry for radiobiology experiments at GANIL

    Science.gov (United States)

    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

    2016-04-01

    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.

  11. Multiple Molecular and Cellular Mechanisms of Action of Lycopene in Cancer Inhibition

    Directory of Open Access Journals (Sweden)

    Cristina Trejo-Solís

    2013-01-01

    Full Text Available Epidemiological studies suggest that including fruits, vegetables, and whole grains in regular dietary intake might prevent and reverse cellular carcinogenesis, reducing the incidence of primary tumours. Bioactive components present in food can simultaneously modulate more than one carcinogenic process, including cancer metabolism, hormonal balance, transcriptional activity, cell-cycle control, apoptosis, inflammation, angiogenesis and metastasis. Some studies have shown an inverse correlation between a diet rich in fruits, vegetables, and carotenoids and a low incidence of different types of cancer. Lycopene, the predominant carotenoid found in tomatoes, exhibits a high antioxidant capacity and has been shown to prevent cancer, as evidenced by clinical trials and studies in cell culture and animal models. In vitro studies have shown that lycopene treatment can selectively arrest cell growth and induce apoptosis in cancer cells without affecting normal cells. In vivo studies have revealed that lycopene treatment inhibits tumour growth in the liver, lung, prostate, breast, and colon. Clinical studies have shown that lycopene protects against prostate cancer. One of the main challenges in cancer prevention is the integration of new molecular findings into clinical practice. Thus, the identification of molecular biomarkers associated with lycopene levels is essential for improving our understanding of the mechanisms underlying its antineoplastic activity.

  12. Cellular mechanisms of high mobility group 1 (HMGB-1 protein action in the diabetic retinopathy.

    Directory of Open Access Journals (Sweden)

    Andrea Rachelle C Santos

    Full Text Available Diabetic retinopathy is one of the main microvascular complications of diabetes and remains one of the leading causes of blindness worldwide. Recent studies have revealed an important role of inflammatory and proangiogenic high mobility group 1 (HMGB-1 cytokine in diabetic retinopathy. To elucidate cellular mechanisms of HMGB-1 activity in the retina, we performed this study. The histological features of diabetic retinopathy include loss of blood-vessel pericytes and endothelial cells, as well as abnormal new blood vessel growth. To establish the role of HMGB-1 in vulnerability of endothelial cells and pericytes, cultures of these cells, or co-cultures with glial cells, were treated with HMGB-1 and assessed for survival after 24 hours. The expression levels of the cytokines, chemokines, and cell adhesion molecules in glial and endothelial cells were tested by quantitative RT-PCR to evaluate changes in these cells after HMGB-1 treatment. Animal models of neovascularization were also used to study the role of HMGB-1 in the retina. We report that pericyte death is mediated by HMGB-1-induced cytotoxic activity of glial cells, while HMGB-1 can directly mediate death of endothelial cells. We also found that HMGB-1 affects endothelial cell activity. However, we did not observe a difference in the levels of neovascularization between HMGB-1-treated eyes compared to the control eyes, nor in the levels of proangiogenic cytokine VEGF-A expression between glial cells treated with HMGB-1 and control cells. Our data also indicate that HMGB-1 is not involved in retinal neovascularization in the oxygen-induced retinopathy model. Thus, our data suggest that retinal pericyte and endothelial injury and death in diabetic retinopathy may be due to HMGB-1-induced cytotoxic activity of glial cells as well as the direct effect of HMGB-1 on endothelial cells. At the same time, our findings indicate that HMGB-1 plays an insignificant role in retinal and choroidal

  13. The relevance of cellular to clinical electrophysiology in classifying antiarrhythmic actions.

    Science.gov (United States)

    Vaughan Williams, E M

    1992-01-01

    The division of class I antiarrhythmic agents (sodium-channel blockers) into Ia, Ib, and Ic subgroups was based on clinical observations. Lidocaine, mexiletine, and tocainide (Ib) did not alter the QRS or H-V interval in sinus rhythm, but prolonged effective refractory period (ERP) in spite of some shortening of the J-T interval. Encainide, flecainide, and lorcainide (Ic) widened the QRS and prolonged H-V in sinus rhythm and at low concentration, but had little effect on the ERP or J-T. These clinical findings could be explained by fast onset/offset kinetics of Ib drugs, that when used in high concentrations, blocked most sodium channels during the action potential plateau; therefore, at the beginning of diastole, insufficient drug-free channels were available to support conduction, and the ERP was prolonged. Rapid dissociation of the drugs after repolarization insured that by the end of diastole most channels were again drug free, so that the QRS and H-V were normal. The Ic compounds were more potent, but of slow onset, so that a steady-state block of Na channels was not achieved until after many beats. Offset was also slow, so that a proportion of channels was persistently unavailable, Na current was reduced, and conduction slowed, causing widening of the QRS and lengthening of H-V. Because the remaining drug-free channels were normal, they recovered rapidly from inactivation, and the ERP was not prolonged. By clinical criteria, moricizine also must be classed as Ic, and its offset/onset kinetics are much slower than those of Ib drugs.(ABSTRACT TRUNCATED AT 250 WORDS)

  14. Physics and radiobiology of nuclear medicine

    CERN Document Server

    Saha, Gopal B

    2010-01-01

    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

  15. Radiation monitoring considerations for radiobiology facilities

    International Nuclear Information System (INIS)

    Battelle, Pacific Northwest Laboratories, conducts a wide variety of radiobiology and radioecology research in a number of facilities on the Hanford Reservation. Review of radiation monitoring problems associated with storage, plant and animal experiments, waste handling and sterile facilities shows that careful monitoring, strict procedural controls and innovative techniques are required to minimize occupational exposure and control contamination. Although a wide variety of radioactivity levels are involved, much of the work is with extremely low level materials. Monitoring low level work is mundane and often impractical but cannot be ignored in today's ever tightening controls

  16. Radiobiological studies using gamma and x rays.

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-02-01

    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.

  17. Generalized calculus in radiobiology: Physical implications

    CERN Document Server

    Sotolongo-Grau, O; Antoranz, J C; Sotolongo-Costa, Oscar

    2009-01-01

    Non-extensive statistical physics has allowed to generalize mathematical functions such as exponential and logarithms. The same framework is used to generalize sum and product so that the operations allow a more fluid way to work with mathematical expressions emerging from non-additive formulation of statistical physics. In this work we employ the generalization of the exponential, logarithm and product to obtain a formula for the survival fraction corresponding to the application of several radiation doses on a living tissue. Also we provide experimental recommendations to determine the universal characteristics of living tissues in interaction with radiation. These results have a potential application in radiobiology and radiation oncology.

  18. Radiobiological investigations of the accelerators at the Joint Institute for Nuclear Research

    International Nuclear Information System (INIS)

    Full text: The Joint Institute for Nuclear Research (JINR) has the different accelerators of heavy charged particles for various energies. The radiobiological investigations at these machines have been commenced some tens years ago. The main task of scientific research at the Laboratory of Radiation Biology of JINR is connected with investigations of genetic effects of accelerated charged particles with wide spectrum of energies. Using accelerated heavy ions with low energy, the following directions of researches in radiobiology and radiation genetics were performed: study of RBE problem in connection with DNA repair processes; investigation of the molecular mechanisms of point and structural mutation induction in prokaryotic cells and the influence of the repair systems on the mutagenic processes after irradiation in a wide range of linear energy transfer (LET); study of the SOS-response of bacterial cells by using SOS-chromo test, SOS-lux test and by criteria of α-prophage induction in lysogenic bacteria after irradiation by heavy ions; study of the regularities of gene mutation inductions in yeast cells under action of ionizing radiation with different LET; investigations of the regularities of unstable and stable chromosomal aberrations (translocations) in human cells under action of ionizing radiation with wide LET range; study of mutagenic (HPRT gene) effects in mammalian cells in culture after heavy charged particle irradiation and chromosomal instability in HPRT-mutant clones after irradiation; study of the cytogenetic effects in mammalian cells irradiated by heavy ions in low doses. The radiobiological investigations with high energy are carried out at the Nuclotron - the new JINR accelerator. The programme involves the most vital tasks of modern radiobiology: study of the regularities and mechanisms of stable and unstable chromosome aberration induction in human cells; genetic control of check-point regulation in low eukaryotic cells; study of the

  19. Melanomas: radiobiology and role of radiation therapy

    International Nuclear Information System (INIS)

    Purpose/Objective: This course will review the radiobiology of malignant melanoma (MM) and the clinical use of radiation therapy for metastatic melanoma and selected primary sites. The course will emphasize the scientific principles underlying the clinical treatment of MM. Introduction: The incidence of malignant melanoma has one of the fastest growth rates in the world. In 1991, there were 32,000 cases and 7,000 deaths from MM in the United States. By the year 2000, one of every 90 Americans will develop MM. Wide local excision is the treatment of choice for Stage I-II cutaneous MM. Five-year survival rates depend on (a) sex: female-63%, male-40%; (b) tumor thickness: t 4 mm-25%; (c) location: extremity-60%, trunk-41%; and (d) regional lymph node status: negative-77%, positive-31%. Despite adequate surgery, 45-50% of all MM patients will develop metastatic disease. Radiobiology: Both the multi-target model: S = 1-(1-e-D/Do)n and the linear quadratic mode: -In(S) = alpha x D + beta x D2 predict a possible benefit for high dose per fraction (> 400 cGy) radiation therapy for some MM cell lines. The extrapolation number (n) varies from 1-100 for MM compared to other mammalian cells with n=2-4. The alpha/beta ratios for a variety of MM cell lines vary from 1 to 33. Other radiobiologic factors (repair of potentially lethal damage, hypoxia, reoxygenation, and repopulation) predict a wide variety of clinical responses to different time-dose prescriptions including high dose per fraction (> 400 cGy), low dose per fraction (200-300 cGy), or b.i.d. therapy. Based on a review of the radiobiology of MM, no single therapeutic strategy emerges which could be expected to be successful for all tumors. Time-Dose Prescriptions: A review of the retrospective and prospective clinical trials evaluating various time-dose prescriptions for MM reveals: (1) MM is a radiosensitive tumor over a wide range of diverse time-dose prescriptions; and (2) The high clinical response rates to a

  20. [Radiobiological analysis of cancerogenic risk values in radioepidemiological investigations].

    Science.gov (United States)

    Rozhdestvenskiĭ, L M

    2008-01-01

    The aim of the present article consisted in critical analysis of the epidemiological approach to radiocancerogenic risk estimation in region of low level radiation (LLR). The estimation is making by means of mathematician models that ignore a principal difference in biological action of LLR and high level radiation (HLR). The main formal characteristic of LLR action is the presence of a plateau in beginning of a dose-effect curve of radiogenic risk. It may be argued by the following positions: repeating the plateau-phenomenon on various radiobiological effects, in different tests and bioobjects, first; a paradoxical trend of reciprocal ERR/Sv increasing regarding dose decreasing in region of plateau, second, and third, the increasing of the curvature in dose-effect curve beginning. The presence of a plateau is associated with the presence of a real radiogenic risk threshold. Besides, the analysis of processes influencing significantly the dynamics of initial radiation injury of biologically important macromolecules showed the preference in region of LLR those, decreasing/eliminating genome damages. There is follows from mentioned above a necessity to evaluate radiogenic risks in LLR region separately from HLR region. PMID:18825986

  1. Cellular Automata-based Chloride Ion Diffusion Simulation of Concrete Bridges under Multi-factor Coupling Actions

    Institute of Scientific and Technical Information of China (English)

    ZHU Jinsong; HE Likun

    2012-01-01

    Abstract In order to accurately simulate the diffusion of chloride ion in the existing concrete bridge and acquire the precise chloride ion concentration at given time,a cellular automata (CA)-based model is proposed.The process of chloride ion diffusion is analyzed by the CA-based method and a nonlinear solution of the Fick's second law is obtained.Considering the impact of various factors such as stress states,temporal and spatial variability of diffusion parameters and water-cement ratio on the process of chloride ion diffusion,the model of chloride ion diffusion under multi-factor coupling actions is presented.A chloride ion penetrating experiment reported in the literature is used to prove the effectiveness and reasonability of the present method,and a T-type beam is taken as an illustrative example to analyze the process of chloride ion diffusion in practical application.The results indicate that CA-based method can simulate the diffusion of chloride ion in the concrete structures with acceptable precision.

  2. Physics and radiobiology of nuclear medicine

    CERN Document Server

    Saha, Gopal B

    2013-01-01

    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.

  3. BNL ACCELERATOR-BASED RADIOBIOLOGY FACILITIES

    Energy Technology Data Exchange (ETDEWEB)

    LOWENSTEIN,D.I.

    2000-05-28

    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.

  4. Radiobiology with heavy charged particles: a historical review

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-09-01

    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)

  5. Radiobiology of Radiosurgery for the Central Nervous System

    Directory of Open Access Journals (Sweden)

    Antonio Santacroce

    2013-01-01

    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.

  6. In vitro irradiation system for radiobiological experiments

    International Nuclear Information System (INIS)

    Although two-dimensional (2-D) monolayer cell cultures provide important information on basic tumor biology and radiobiology, they are not representative of the complexity of three-dimensional (3-D) solid tumors. In particular, new models reproducing clinical conditions as closely as possible are needed for radiobiological studies to provide information that can be translated from bench to bedside. We developed a novel system for the irradiation, under sterile conditions, of 3-D tumor spheroids, the in vitro model considered as a bridge between the complex architectural organization of in vivo tumors and the very simple one of in vitro monolayer cell cultures. The system exploits the same equipment as that used for patient treatments, without the need for dedicated and highly expensive instruments. To mimic the passage of radiation beams through human tissues before they reach the target tumor mass, 96-multiwell plates containing the multicellular tumor spheroids (MCTS) are inserted into a custom-built phantom made of plexiglass, the material most similar to water, the main component of human tissue. The system was used to irradiate CAEP- and A549-derived MCTS, pre-treated or not with 20 μM cisplatin, with a dose of 20 Gy delivered in one session. We also tested the same treatment schemes on monolayer CAEP and A549 cells. Our preliminary results indicated a significant increment in radiotoxicity 20 days after the end of irradiation in the CAEP spheroids pre-treated with cisplatin compared to those treated with cisplatin or irradiation alone. Conversely, the effect of the radio- chemotherapy combination in A549-derived MCTS was similar to that induced by cisplatin or irradiation alone. Finally, the 20 Gy dose did not affect cell survival in monolayer CAEP and A549 cells, whereas cisplatin or cisplatin plus radiation caused 100% cell death, regardless of the type of cell line used. We set up a system for the irradiation, under sterile conditions, of tumor cells

  7. Heavy-ion tumor therapy: Physical and radiobiological benefits

    Science.gov (United States)

    Schardt, Dieter; Elsässer, Thilo; Schulz-Ertner, Daniela

    2010-01-01

    High-energy beams of charged nuclear particles (protons and heavier ions) offer significant advantages for the treatment of deep-seated local tumors in comparison to conventional megavolt photon therapy. Their physical depth-dose distribution in tissue is characterized by a small entrance dose and a distinct maximum (Bragg peak) near the end of range with a sharp fall-off at the distal edge. Taking full advantage of the well-defined range and the small lateral beam spread, modern scanning beam systems allow delivery of the dose with millimeter precision. In addition, projectiles heavier than protons such as carbon ions exhibit an enhanced biological effectiveness in the Bragg peak region caused by the dense ionization of individual particle tracks resulting in reduced cellular repair. This makes them particularly attractive for the treatment of radio-resistant tumors localized near organs at risk. While tumor therapy with protons is a well-established treatment modality with more than 60 000 patients treated worldwide, the application of heavy ions is so far restricted to a few facilities only. Nevertheless, results of clinical phase I-II trials provide evidence that carbon-ion radiotherapy might be beneficial in several tumor entities. This article reviews the progress in heavy-ion therapy, including physical and technical developments, radiobiological studies and models, as well as radiooncological studies. As a result of the promising clinical results obtained with carbon-ion beams in the past ten years at the Heavy Ion Medical Accelerator facility (Japan) and in a pilot project at GSI Darmstadt (Germany), the plans for new clinical centers for heavy-ion or combined proton and heavy-ion therapy have recently received a substantial boost.

  8. Biophysical and biomathematical adventures in radiobiology

    International Nuclear Information System (INIS)

    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

  9. Estimation of Radiobiologic Parameters and Equivalent Radiation Dose of Cytotoxic Chemotherapy in Malignant Glioma

    International Nuclear Information System (INIS)

    Purpose: To determine the radiobiologic parameters for high-grade gliomas. Methods and Materials: The biologic effective dose concept is used to estimate the α/β ratio and K (dose equivalent for tumor repopulation/d) for high-grade glioma patients treated in a randomized fractionation trial. The equivalent radiation dose of temozolomide (Temodar) chemotherapy was estimated from another randomized study. The method assumes that the radiotherapy biologic effective dose is proportional to the adjusted radiotherapy survival duration of high-grade glioma patients. Results: The median tumor α/β and K estimate is 9.32 Gy and 0.23 Gy/d, respectively. Using the published surviving fraction after 2-Gy exposure (SF2) data, and the above α/β ratio, the estimated median α value was 0.077 Gy-1, β was 0.009 Gy-2, and the cellular doubling time was 39.5 days. The median equivalent biologic effective dose of temozolomide was 11.03 Gy9.3 (equivalent to a radiation dose of 9.1 Gy given in 2-Gy fractions). Random sampling trial simulations based on a cure threshold of 70 Gy in high-grade gliomas have shown the potential increase in tumor cure with dose escalation. Partial elimination of hypoxic cells (by chemical hypoxic cell sensitizers or carbon ion therapy) has suggested that considerable gains in tumor control, which are further supplemented by temozolomide, are achievable. Conclusion: The radiobiologic parameters for human high-grade gliomas can be estimated from clinical trials and could be used to inform future clinical trials, particularly combined modality treatments with newer forms of radiotherapy. Other incurable cancers should be studied using similar radiobiologic analysis

  10. Toward a national consensus: teaching radiobiology to radiation oncology residents

    International Nuclear Information System (INIS)

    Purpose: The ASTRO Joint Working Group on Radiobiology Teaching, a committee composed of members having affiliations with several national radiation oncology and biology-related societies and organizations, commissioned a survey designed to address issues of manpower, curriculum standardization, and instructor feedback as they relate to resident training in radiation biology. Methods and Materials: Radiation biology instructors at U.S. radiation oncology training programs were identified and asked to respond to a comprehensive electronic questionnaire dealing with instructor educational background, radiation biology course content, and sources of feedback with respect to curriculum planning and resident performance on standardized radiation biology examinations. Results: Eighty-five radiation biology instructors were identified, representing 73 radiation oncology residency training programs. A total of 52 analyzable responses to the questionnaire were received, corresponding to a response rate of 61.2%. Conclusion: There is a decreasing supply of instructors qualified to teach classic, and to some extent, clinical, radiobiology to radiation oncology residents. Additionally, those instructors with classic training in radiobiology are less likely to be comfortable teaching cancer molecular biology or other topics in cancer biology. Thus, a gap exists in teaching the whole complement of cancer and radiobiology curricula, particularly in those programs in which the sole responsibility for teaching falls to one faculty member (50% of training programs are in this category). On average, the percentage of total teaching time devoted to classic radiobiology (50%), clinical radiobiology (30%), and molecular and cancer biology (20%) is appropriate, relative to the current makeup of the board examination. Nevertheless large variability exists between training programs with respect to the total number of contact hours per complete radiobiology course (ranging from

  11. National Radiobiology Archives distributed access programmer's guide

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-12-01

    The National Radiobiology Archives is a comprehensive effort to gather, organize, and catalog original data, representative specimens, and supporting materials related to significant radiobiology studies. This provides researchers with information for analyses which compare or combine results of these and other studies and with materials for analysis by advanced molecular biology techniques. This Programmer's Guide document describes the database access software, NRADEMO, and the subset loading script NRADEMO/MAINT/MAINTAIN, which comprise the National Laboratory Archives Distributed Access Package. The guide is intended for use by an experienced database management specialist. It contains information about the physical and logical organization of the software and data files. It also contains printouts of all the scripts and associated batch processing files. It is part of a suite of documents published by the National Radiobiology Archives.

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

    Science.gov (United States)

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

    1998-01-01

    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.

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

    Science.gov (United States)

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

    2016-08-01

    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.

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

    Science.gov (United States)

    Blakely, E A; Kronenberg, A

    1998-11-01

    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.

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

    Science.gov (United States)

    Blakely, E A; Kronenberg, A

    1998-11-01

    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. PMID:9806616

  16. Population of Computational Rabbit-Specific Ventricular Action Potential Models for Investigating Sources of Variability in Cellular Repolarisation

    OpenAIRE

    Philip Gemmell; Kevin Burrage; Blanca Rodriguez; T Alexander Quinn

    2014-01-01

    Variability is observed at all levels of cardiac electrophysiology. Yet, the underlying causes and importance of this variability are generally unknown, and difficult to investigate with current experimental techniques. The aim of the present study was to generate populations of computational ventricular action potential models that reproduce experimentally observed intercellular variability of repolarisation (represented by action potential duration) and to identify its potential causes. A s...

  17. DNA-Destabilizing Agents as an Alternative Approach for Targeting DNA: Mechanisms of Action and Cellular Consequences

    Directory of Open Access Journals (Sweden)

    Gaëlle Lenglet

    2010-01-01

    Full Text Available DNA targeting drugs represent a large proportion of the actual anticancer drug pharmacopeia, both in terms of drug brands and prescription volumes. Small DNA-interacting molecules share the ability of certain proteins to change the DNA helix's overall organization and geometrical orientation via tilt, roll, twist, slip, and flip effects. In this ocean of DNA-interacting compounds, most stabilize both DNA strands and very few display helix-destabilizing properties. These types of DNA-destabilizing effect are observed with certain mono- or bis-intercalators and DNA alkylating agents (some of which have been or are being developed as cancer drugs. The formation of locally destabilized DNA portions could interfere with protein/DNA recognition and potentially affect several crucial cellular processes, such as DNA repair, replication, and transcription. The present paper describes the molecular basis of DNA destabilization, the cellular impact on protein recognition, and DNA repair processes and the latter's relationships with antitumour efficacy.

  18. Expression patterns and action analysis of genes associated with physiological responses during rat liver regeneration: Cellular immune response

    Institute of Scientific and Technical Information of China (English)

    Lian-Xing Zhang; Li-Feng Zhao; An-Shi Zhang; Xiao-Guang Chen; Cun-Shuan Xu

    2006-01-01

    AIM: To study the cellular immune response during rat liver regeneration (LR) at a transcriptional level.METHODS: Genes associated with the cellular immune response were obtained by collecting the data from databases and retrieving articles. Gene expression changes during LR were detected by rat genome 230 2.0 array.RESULTS: A total of 127 genes were found to be associated with LR. The number of initially and totally expressing genes in the initial phase of LR [0.5-4 h after partial hepatectomy (PH)], transition from G0-G1(4-6 h after PH), cell proliferation (6-66 h after PH),cell differentiation and structure-function reconstruction (66-168 h after PH) was 54, 11, 34, 3 and 54, 49, 70, 49 respectively, illustrating that the associated genes were mainly triggered at the initiation of LR, and worked at different phases. According to their expression similarity,these genes were classified into 41 up-regulated, 21 predominantly up-regulated, 41 down-regulated, 14 predominantly down-regulated, 10 similarly up-regulated and down-regulated genes, respectively. The total upand down-regulated expression times were 419 and 274,respectively, demonstrating that the expression of most genes was increased while the expression of a small number of genes was decreased. Their time relevance was classified into 14 groups, showing that the cellular physiological and biochemical activities were staggered during LR. According to the gene expression patterns,they were classified into 21 types, showing the activities were diverse and complicated during LR.CONCLUSION: Antigen processing and presentation are enhanced mainly in the forepart, prophase and anaphase of LR. T-cell activation and antigen elimination are enhanced mainly in the forepart and prophase of LR. A total of 127 genes associated with LR play an important role in cellular immunity.

  19. Antioxidant action of SMe1EC2, the low-basicity derivative of the pyridoindole stobadine, in cell free chemical models and at cellular level.

    Science.gov (United States)

    Balcerczyk, Aneta; Bartosz, Grzegorz; Drzewinska, Joanna; Piotrowski, Łukasz; Pulaski, Łukasz; Stefek, Milan

    2014-03-01

    The aim of the study was to evaluate the antioxidant action of SMe1EC2, the structural analogue of the hexahydropyridoindole antioxidant stobadine. The antiradical activity of SMe1EC2 was found to be higher when compared to stobadine, as determined both in cell-free model systems of AAPH-induced oxidation of dihydrorhodamine 123 and 2',7'-dichloro-dihydrofluorescein diacetate, and in the cellular system of stimulated macrophages RAW264.7. Analysis of proliferation of HUVEC and HUVEC-ST cells revealed absence of cytotoxic effect of SMe1EC2 at concentrations below 100 µM. The antioxidant activity of SMe1EC2, superior to the parent drug stobadine, is accounted for by both the higher intrinsic free radical scavenging action and by the better bioavailability of the low-basicity SMe1EC2 relative to the high-basicity stobadine.

  20. Research in radiobiology. Annual report, Internal Irradiation Program

    International Nuclear Information System (INIS)

    The annual progress report for the Radiobiology Division of the University of Utah College of Medicine is presented. Summaries of twenty-four projects concerning the metabolism, dosimetry and toxicity of a variety of actinide elements in beagles or rats are given. Individual papers within this report have been separately indexed and abstracted for the data base

  1. National Radiobiology Archives Distributed Access user's manual

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-11-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-01-01

    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

    Science.gov (United States)

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

    1992-01-01

    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. Micro-and nanodosimetry for radiobiological planning in radiotherapy and cancer risk assessment in radiation environment

    International Nuclear Information System (INIS)

    Full text: Microdosimetry and nanodosimetry can provide unique information for prediction of radiobiological properties of radiation, which is important in radiation therapy for accurate dose planning and in radiation protection for cancer induction risk assessment. This demand measurements of the pattern of energies deposited by ionizing radiation on cellular scale and DNA levels.Silicon microelectronics technology is offering a unique opportunity for replacing gas proportional counters (TEPC) with miniature detectors for regional microdosimetry. Silicon on Insulator (SOI) technology has been used for the development of arrays of micron size sensitive volumes for modelling energy deposited in biological cells. The challenge in silicon microdosimetry is the development of well defined sensitive volume (SV) and full charge collection deposited by ionizing radiation in the SV. First generation SOI microdosimeters were developed at CMRP and investigated in a wide range of radiation fields for proton and neutron therapies and recently on isotopic neutron sources and heavy ions with energy up to lGeV/jj,m which are typical for deep space radiation environment. Microdosimetric spectra were obtained in a phantom that are well matched to TEPC and Monte Carlo simulations. Evidence that radiations with the same LET exhibit different biological effects demand development of new sensors sensitive to the track structure of ions or the type of particle for prediction of radiobiological effect of radiation using radiobiological models. New monolithic Si AE-E telescope of cellular size for simultaneous regional microdosimetry and particle identification will be presented and results will be discussed. The new design of the SOI microdosimeter is based on 3D micron and submicron size of Si SVs. This approach allows improvement in the accuracy of the Si microdosimetry because of full charge collection and the ability to measure low LET as low as 0.01 keV/jjm, which is similar to TEPC

  5. Experimental radiotherapy and clinical radiobiology. Vol. 16

    International Nuclear Information System (INIS)

    The following topics were dealt with: DNA repair as therapeutical target in radiation therapy, biological imaging and tumor microenvironment, molecular factors of radiation therapy, molecular factors and modulation of the radiation reaction of normal tissues, experimental tumor therapy, EGFR inhibition, the endothel cell as primary target of radiation therapy, molecular and cellular foundations of the radiation biology of protons and ions. (HSI)

  6. Molecular, cellular and medical aspects of the action of nutraceuticals and small molecules therapeutics: from chemoprevention to new drug development.

    Science.gov (United States)

    Colic, M; Pavelic, K

    2002-01-01

    Dietary supplements, functional foods and their concentrated, sometimes purified, active forms, the so-called nutraceuticals, are becoming increasingly popular throughout the world. Small molecules that regulate signal transduction cascades and gene expression are being tested by many pharmaceutical companies. A rapidly and exponentially growing industry (close to $30 billion in 1999 worldwide) exists to commercialize and exploit this interest. However, the scientific basis of the action of such unproved products is in the very early stages of development. While supporters claim they produce miracle cures, opponents argue that such unproved agents do more harm than good. PMID:12635491

  7. Loss of progesterone receptor-mediated actions induce preterm cellular and structural remodeling of the cervix and premature birth.

    Directory of Open Access Journals (Sweden)

    Steven M Yellon

    Full Text Available A decline in serum progesterone or antagonism of progesterone receptor function results in preterm labor and birth. Whether characteristics of premature remodeling of the cervix after antiprogestins or ovariectomy are similar to that at term was the focus of the present study. Groups of pregnant rats were treated with vehicle, a progesterone receptor antagonist (onapristone or mifepristone, or ovariectomized on day 17 postbreeding. As expected, controls given vehicle delivered at term while rats delivered preterm after progesterone receptor antagonist treatment or ovariectomy. Similar to the cervix before term, the preterm cervix of progesterone receptor antagonist-treated rats was characterized by reduced cell nuclei density, decreased collagen content and structure, as well as a greater presence of macrophages per unit area. Thus, loss of nuclear progesterone receptor-mediated actions promoted structural remodeling of the cervix, increased census of resident macrophages, and preterm birth much like that found in the cervix at term. In contrast to the progesterone receptor antagonist-induced advance in characteristics associated with remodeling, ovariectomy-induced loss of systemic progesterone did not affect hypertrophy, extracellular collagen, or macrophage numbers in the cervix. Thus, the structure and macrophage census in the cervix appear sufficient for premature ripening and birth to occur well before term. With progesterone receptors predominantly localized on cells other than macrophages, the findings suggest that interactions between cells may facilitate the loss of progesterone receptor-mediated actions as part of a final common mechanism that remodels the cervix in certain etiologies of preterm and with parturition at term.

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

    Science.gov (United States)

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

    2016-07-01

    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

  9. Increased Cellular NAD+ Level through NQO1 Enzymatic Action Has Protective Effects on Bleomycin-Induced Lung Fibrosis in Mice

    Science.gov (United States)

    Oh, Gi-Su; Lee, Su-Bin; Karna, Anjani; Kim, Hyung-Jin; Shen, AiHua; Pandit, Arpana; Lee, SeungHoon

    2016-01-01

    Background Idiopathic pulmonary fibrosis is a common interstitial lung disease; it is a chronic, progressive, and fatal lung disease of unknown etiology. Over the last two decades, knowledge about the underlying mechanisms of pulmonary fibrosis has improved markedly and facilitated the identification of potential targets for novel therapies. However, despite the large number of antifibrotic drugs being described in experimental pre-clinical studies, the translation of these findings into clinical practices has not been accomplished yet. NADH:quinone oxidoreductase 1 (NQO1) is a homodimeric enzyme that catalyzes the oxidation of NADH to NAD+ by various quinones and thereby elevates the intracellular NAD+ levels. In this study, we examined the effect of increase in cellular NAD+ levels on bleomycin-induced lung fibrosis in mice. Methods C57BL/6 mice were treated with intratracheal instillation of bleomycin. The mice were orally administered with β-lapachone from 3 days before exposure to bleomycin to 1-3 weeks after exposure to bleomycin. Bronchoalveolar lavage fluid (BALF) was collected for analyzing the infiltration of immune cells. In vitro, A549 cells were treated with transforming growth factor β1 (TGF-β1) and β-lapachone to analyze the extracellular matrix (ECM) and epithelial-mesenchymal transition (EMT). Results β-Lapachone strongly attenuated bleomycin-induced lung inflammation and fibrosis, characterized by histological staining, infiltrated immune cells in BALF, inflammatory cytokines, fibrotic score, and TGF-β1, α-smooth muscle actin accumulation. In addition, β-lapachone showed a protective role in TGF-β1–induced ECM expression and EMT in A549 cells. Conclusion Our results suggest that β-lapachone can protect against bleomycin-induced lung inflammation and fibrosis in mice and TGF-β1–induced EMT in vitro, by elevating the NAD+/NADH ratio through NQO1 activation.

  10. Optimization in brachytherapy with the implementation of Radiobiology

    International Nuclear Information System (INIS)

    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)

  11. Radiobiology Department. Report of Activities 1977-1980

    International Nuclear Information System (INIS)

    The different research activities carried out by the Radiobiology Department of the CNEA over the 4-year period 1977-1980 are summarized. These activities were devoted to the study of the effects of radiation on different biological systems, to the search for adequate experimental models, and to the development of techniques permiting a correct evaluation of the information obtained. Topics covered are genetics, microbiology, somatic effects of radiation, pathology and the operation of the animal's house. (M.E.L.)

  12. In vitro irradiation station for broad beam radiobiological experiments

    Science.gov (United States)

    Wéra, A.-C.; Riquier, H.; Heuskin, A.-C.; Michiels, C.; Lucas, S.

    2011-12-01

    The study of the interaction of charged particles with living matter is of prime importance to the fields of radiotherapy, radioprotection and space radiobiology. Particle accelerators and their associated equipment are proven to be helpful tools in performing basic science in all these fields. Indeed, they can accelerate virtually any ions to a given energy and flux and let them interact with living matter either in vivo or in vitro. In this context, the University of Namur has developed a broad beam in vitro irradiation station for use in radiobiological experiments. Cells are handled in GLP conditions and can be irradiated at various fluxes with ions ranging from hydrogen to carbon. The station is mounted on a 2 MV tandem accelerator, and the energy range can be set up in the linear energy transfer (LET) ranges that are useful for radiobiological experiments. This paper describes the current status of the hardware that has been developed, and presents results related to its performance in term of dose-rate, energy range and beam uniformity for protons, alpha particles and carbon ions. The results of clonogenic assays of A549 lung adenocarcinoma cells irradiated with protons and alpha particles are also presented and compared with literature.

  13. In vitro irradiation station for broad beam radiobiological experiments

    Energy Technology Data Exchange (ETDEWEB)

    Wera, A.-C., E-mail: anne-catharine.wera@fundp.ac.be [NAmur Research Institute for LIfe Sciences (NARILIS), Research Centre for the Physics of Matter and Radiation (PMR), University of Namur-FUNDP (Belgium); Riquier, H., E-mail: helene.riquier@fundp.ac.be [NAmur Research Institute for LIfe Sciences (NARILIS), Unite de Recherche de Biologie Cellulaire (URBC), University of Namur-FUNDP, Rue de Bruxelles, 61, B-5000 Namur (Belgium); Heuskin, A.-C., E-mail: anne-catherine.heuskin@fundp.ac.be [NAmur Research Institute for LIfe Sciences (NARILIS), Research Centre for the Physics of Matter and Radiation (PMR), University of Namur-FUNDP (Belgium); Michiels, C., E-mail: carine.michiels@fundp.ac.be [NAmur Research Institute for LIfe Sciences (NARILIS), Unite de Recherche de Biologie Cellulaire (URBC), University of Namur-FUNDP, Rue de Bruxelles, 61, B-5000 Namur (Belgium); Lucas, S., E-mail: stephane.lucas@fundp.ac.be [NAmur Research Institute for LIfe Sciences (NARILIS), Research Centre for the Physics of Matter and Radiation (PMR), University of Namur-FUNDP (Belgium)

    2011-12-15

    The study of the interaction of charged particles with living matter is of prime importance to the fields of radiotherapy, radioprotection and space radiobiology. Particle accelerators and their associated equipment are proven to be helpful tools in performing basic science in all these fields. Indeed, they can accelerate virtually any ions to a given energy and flux and let them interact with living matter either in vivo or in vitro. In this context, the University of Namur has developed a broad beam in vitro irradiation station for use in radiobiological experiments. Cells are handled in GLP conditions and can be irradiated at various fluxes with ions ranging from hydrogen to carbon. The station is mounted on a 2 MV tandem accelerator, and the energy range can be set up in the linear energy transfer (LET) ranges that are useful for radiobiological experiments. This paper describes the current status of the hardware that has been developed, and presents results related to its performance in term of dose-rate, energy range and beam uniformity for protons, alpha particles and carbon ions. The results of clonogenic assays of A549 lung adenocarcinoma cells irradiated with protons and alpha particles are also presented and compared with literature.

  14. (RadioBiological Optimization of External-Beam Radiotherapy

    Directory of Open Access Journals (Sweden)

    Alan E. Nahum

    2012-01-01

    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.

  15. Radiobiological modeling with MarCell software

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-01-01

    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.

  16. Impact of microgravity on radiobiological processes and efficiency of DNA repair

    Energy Technology Data Exchange (ETDEWEB)

    Horneck, G. [Radiation Biology Division, Institute of Aerospace Medicine, DLR German Aerospace Center, Linder Hohe, 51170 Cologne (Germany)

    1999-12-06

    To study the influence of microgravity on radiobiological processes in space, space experiments have been performed, using an on-board 1xg reference centrifuge as in-flight control. The trajectory of individual heavy ions was localized in relation to the biological systems by use of the Biostack concept, or an additional high dose of radiation was applied either before the mission or during the mission from an on-board radiation source. In embryonic systems, such as early developmental stages of Drosophila melanogaster and Carausius morosus, the occurrence of chromosomal translocations and larval malformations was dramatically increased in response to microgravity and radiation. It has been hypothesized that these synergistic effects might be caused by an interference of microgravity with DNA repair processes. However, recent studies on bacteria, yeast cells and human fibroblasts suggest that a disturbance of cellular repair processes in the microgravity environment might not be a complete explanation for the reported synergism of radiation and microgravity. As an alternative explanation, an impact of microgravity on signal transduction, on the metabolic/physiological state or on the chromatin structure at the cellular level, or modification of self-assembly, intercellular communication, cell migration, pattern formation or differentiation at the tissue and organ level should be considered.

  17. In vitro and in vivo ion beam targeted micro-irradiation for radiobiology

    International Nuclear Information System (INIS)

    The main goal of radiobiology is to understand the effects of ionizing radiations on the living. These past decades, ion microbeams have shown to be important tools to study for example the effects of low dose exposure, or the bystander effect. Since 2003, the CENBG has been equipped with a system to perform targeted micro-irradiation of living samples. Recently, microbeams applications on this subject have diversified and the study of DNA repair mechanisms at the cellular and multicellular scales, in vitro and in vivo, has become possible thanks to important evolutions of fluorescence imaging techniques and cellular biology. To take into account these new approaches, the CENBG micro-irradiation beamline has been entirely redesigned and rebuilt to implement new features and to improve the existing ones. My PhD objectives were i) commissioning the facility, ii) characterizing the system on track etch detectors, and on living samples, iii) implementing protocols to perform targeted irradiations of living samples with a con-trolled delivered dose, at the cellular and multicellular scales, and to visualize the early consequences online, iv) modelling these irradiations to explain the biological results using the calculated physical data. The work of these past years has allowed us i) to measure the performances of our system: a beam spot size of about 2 μm and a targeting accuracy of ± 2 μm, and to develop ion detection systems for an absolute delivered dose control, ii) to create highly localized radiation-induced DNA damages and to see online the recruitment of DNA repair proteins, iii) to apply these protocols to generate radiation-induced DNA damages in vivo inside a multicellular organism at the embryonic stage: Caenorhabditis elegans. These results have opened up many perspectives on the study of the interaction between ionizing radiations and the living, at the cellular and multicellular scales, in vitro and in vivo. (author)

  18. Studies of UV-cured CR-39 recording properties in view of its applicability in radiobiological experiments with alpha particles

    Energy Technology Data Exchange (ETDEWEB)

    Gaillard, Sylvain [Laboratoire de Microanalyses Nucleaires, UMR CEA E4, UFR Sciences et Techniques, Universite de Franche-Comte, 16 route de Gray, 25030 Besancon cedex (France); Ross, Caroline J. [Radiation and Genome Stability Unit, Medical Research Council, Harwell, Oxfordshire OX11 0RD (United Kingdom); Armbruster, Vincent [Laboratoire d' Optique P.M. DUFFIEUX, UFR Sciences et Techniques, Universite de Franche-Comte, 16 route de Gray, 25030 Besancon cedex (France); Hill, Mark A. [Radiation and Genome Stability Unit, Medical Research Council, Harwell, Oxfordshire OX11 0RD (United Kingdom); Stevens, David L. [Radiation and Genome Stability Unit, Medical Research Council, Harwell, Oxfordshire OX11 0RD (United Kingdom); Gharbi, Tijani [Laboratoire d' Optique P.M. DUFFIEUX, UFR Sciences et Techniques, Universite de Franche-Comte, 16 route de Gray, 25030 Besancon cedex (France); Fromm, Michel [Laboratoire de Microanalyses Nucleaires, UMR CEA E4, UFR Sciences et Techniques, Universite de Franche-Comte, 16 route de Gray, 25030 Besancon cedex (France)

    2005-11-15

    In radiobiology, low doses of high-LET radiation correspond to a few particle traversals through the cell population. Therefore, for studies on cell monolayers irradiated with a low dose of {alpha}-particles, it is extremely useful if the number and position of particle traversals can be determined. In this study we describe a new method, based on UV-curing, to obtain a 10{mu}m thick CR-39 grafted onto a 2.5{mu}m thick PolyEthylene Terephtalate (PET). This thin double polymeric layer, used as a dish base, has a regular and reproducible detector thickness which can be traversed by 3.5MeV {alpha}-particles, with a sufficient residual energy to traverse mammalian cells attached to the base. The recording properties of a PET-CR-39 dish, together with a demonstration of its use for radiobiological experiments, are presented. This new tool allows the precise determination of single-track impact parameters at a sub-cellular level.

  19. Experimental radiotherapy and clinical radiobiology. Vol. 18. Proceedings

    International Nuclear Information System (INIS)

    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

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

    CERN Document Server

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

    1999-01-01

    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.

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

    Science.gov (United States)

    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

    2014-01-01

    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. PMID:24999475

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

    Directory of Open Access Journals (Sweden)

    M. Mangoni

    2014-01-01

    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.

  3. Some applications of radiation chemistry to biochemistry and radiobiology

    International Nuclear Information System (INIS)

    In this chapter illustrate the use of radiation chemistry as a tool in investigating biologically important radical reactions, and also outline some studies of models for radiobiological damage. Because aqueous solutions usually offer the most important matrix, an appreciation of the main features of water radiolysis will be essential. Most of the illustrations involve pulse radiolysis, and some familiarity with chemical kinetics is assumed. In addition to these and other chapters in this book, readers find the proceedings of a recent NATO Advanced Study Institute most useful. The authors shall not try to review here all the applications of radiation chemistry to biochemistry and biology, but they will illustrate, using selected examples, the main principles and practical advantages and problems. Another recent volume covers the main contributions of flash photolysis and pulse radiolysis to the chemistry of biology and medicine, complementing earlier reviews. Papers from symposia on radical processes in radiobiology and carcinogenesis, and on super-oxide dismutases, and proceedings of recent international congresses of radiation research, together with the other publications referred to above will enable the reader to gain a comprehensive overview of the role of radicals in biological processes and the contributions of radiation chemistry

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

    Science.gov (United States)

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

    2016-07-01

    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.

  5. Conjunct action of gamma radiation and casiopeinas in two cellular types; Accion conjunta de radiacion gamma y casiopeinas en dos tipos celulares

    Energy Technology Data Exchange (ETDEWEB)

    Ramos V, N.I

    2006-07-01

    In Mexico the cancer occupies the second place in the causes of death and although already there are diverse useful treatments to attack this suffering, the search of new pharmaceuticals that present positive effect in the treatment of the cancer there is taken to the development of a group of substances called Casiopeinas. Its are coordination compounds constituted by a central atom of copper (Cu II) joined to organic ligands, with general condensed formula [Cu (NN)(ON)]NO{sub 3}, or [Cu(NN)(OO)]NO{sub 3}. Its present different cytotoxicity levels, as well as in vitro antineoplastic activity in diverse tissues derived of tumors. Even its ignore the mechanisms of it action, but one of them, it could be by generation of reactive species of oxygen (ERO), mediated by the metallic center that contain. Thinking of this possibility was carried out in vitro experiments, exposing lymphocytes or HeLa cells, to ionizing radiation, at two casiopeinas (Casiopeina llgly and the Casiopeina Ill-e-a) or the combination of both agents, in order to determine if the antineoplastic capacity of both types of treatments increase in conjunct action. To determine it its were carried out cytotoxicity tests by means of the differential dyeing of fluorescein diacetate and etidio bromide, in these the cells alive fluorescein in green color while the dead ones only the nucleus of red tinged. The genotoxicity was evaluated by means of the comet essay. The results hurtled that as much the casiopeinas as the radiation by separate don't present difference among both cellular types, probably due to the used method that only quantifies the damages at the moment and not to long term. And according to those treatments on the whole only to the concentrations and the doses more high it favors the additive effect due to an overproduction of free radicals that not can be neutralized. According to the genotoxicity, only proven for the radiation indicates that the HeLa cells presents a major number of

  6. Operation and Maintenance of the National Radiobiology Archives

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Anthony C. James; Stacey L. McCord

    2012-03-07

    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

  7. Collimator design for spatially-fractionated proton beams for radiobiology research

    Science.gov (United States)

    Lee, Eunsin; Meyer, Juergen; Sandison, George

    2016-07-01

    Preclinical and translational research is an imperative to improve the efficacy of proton radiotherapy. We present a feasible and practical method to produce spatially-modulated proton beams for cellular and small animal research for clinical and research facilities. The University of Washington (UW) 50.5 MeV proton research beamline hosting a brass collimation system was modeled using Monte Carlo simulations. This collimator consisted of an array of 2 cm long slits to cover an area of 2  ×  2 cm2. To evaluate the collimator design effects on dose rate, valley dose and the peak-to-valley dose ratios (PVDR) the following parameters were varied; slit width (0.1–1.0 mm), peak center-to-center distance (1–3 mm), collimator thickness (1–7 cm) and collimator location along the beam axis. Several combinations of slit widths and 1 mm spacing achieved uniform dose at the Bragg peak while maintaining spatial modulation on the beam entrance. A more detailed analysis was carried out for the case of a slit width of 0.3 mm, peak center-to-center distance of 1 mm, a collimator thickness of 5 cm and with the collimator flush against the water phantom. The dose rate at 5 mm depth dropped relative to an open field by a factor of 12 and produced a PVDR of 10.1. Technical realization of proton mini-beams for radiobiology small animal research is demonstrated to be feasible. It is possible to obtain uniform dose at depth while maintaining reasonable modulation at shallower depths near the beam entrance. While collimator design is important the collimator location has a strong influence on the entrance region PVDRs and on dose rate. These findings are being used to manufacture a collimator for installation on the UW cyclotron proton beam nozzle. This collimator will enable comparative studies on the radiobiological efficacy of x-rays and proton beams.

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

    CERN Document Server

    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

    2016-01-01

    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.

  9. Contribution to fundamental aspects of biophysics, radiobiology, and modeling of cellular response to low radiation doses

    OpenAIRE

    Belchior, Ana Lúcia Vital, 1979-

    2014-01-01

    Tese de doutoramento, Engenharia Biomédica e Biofísica, Universidade de Lisboa, Faculdade de Ciências, 2014 This thesis aims at studying the direct and bystander effects (observations in which effects of ionizing radiation arise in non-irradiated cells) induced by alpha-particle irradiation, using a Po-210 source, in a human lung adenocarcinoma cells (A549), and at investigating and providing a contribution to the clarification of the protective or potentially detrimental effects of low-do...

  10. Method for validating radiobiological samples using a linear accelerator

    International Nuclear Information System (INIS)

    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.)

  11. A statistical method for descriminating between alternative radiobiological models

    International Nuclear Information System (INIS)

    Radiobiological models assist understanding of the development of radiation damage, and may provide a basis for extrapolating dose-effect curves from high to low dose regions. Many models have been proposed such as multitarget and its modifications, enzymatic models, and those with a quadratic dose response relationship (i.e. αD + βD2 forms). It is difficult to distinguish between these because the statistical techniques used are almost always limited, in that one method can rarely be applied to the whole range of models. A general statistical procedure for parameter estimation (Maximum Liklihood Method) has been found applicable to a wide range of radiobiological models. The curve parameters are estimated using a computerised search that continues until the most likely set of values to fit the data is obtained. When the search is complete two procedures are carried out. First a goodness of fit test is applied which examines the applicability of an individual model to the data. Secondly an index is derived which provides an indication of the adequacy of any model compared with alternative models. Thus the models may be ranked according to how well they fit the data. For example, with one set of data, multitarget types were found to be more suitable than quadratic types (αD + βD2). This method should be of assitance is evaluating various models. It may also be profitably applied to selection of the most appropriate model to use, when it is necessary to extrapolate from high to low doses

  12. The radiobiology/radiation protection interface in healthcare

    International Nuclear Information System (INIS)

    The current knowledge of radiation effects is reviewed and implications for its application in healthcare considered. The 21st L H Gray conference gathered leading experts in radiobiology, radiation epidemiology, radiation effect modelling, and the application of radiation in medicine to provide an overview of the subject. The latest radiobiology research in non-targeted effects such as genomic instability and the bystander effect challenge the old models, but the implications for health effects on humans are uncertain. Adaptive responses to external stresses, of which radiation is one, have been demonstrated in cells and animal models, but it is not known how these might modify human dose-effect relationships. Epidemiological evidence from the Japanese A-bomb survivors provides strong evidence that there is a linear relationship between the excess risk of cancer and organ dose that extends from about 50 mSv up to 2.5 Sv, and results from pooled data for multiple epidemiological studies indicate that risks extend down to doses of 20 mSv. Thus linear extrapolation of the A-bomb dose-effect data provides an appropriate basis for radiological protection standards at the present time. Risks from higher dose diagnostic procedures fall within the range in which health effects can be demonstrated. There is therefore reason for concern about the rise in the number of computed tomography (CT) scans performed in many countries, and in particular the use of CT for screening of asymptomatic individuals. New radiotherapy techniques allow high dose radiation fields to be conformed more effectively to target volumes, and reduce doses to critical organs, but they tend to give a higher and more uniform dose to the whole body which may increase the risk of second cancer. It is important that radiation protection practitioners keep abreast of developments in understanding of radiation effects and advise the medical community about the implications of fundamental research when

  13. Strategies to improve the efficacy of radioimmunotherapy: Radiobiologic aspects

    International Nuclear Information System (INIS)

    The purpose of this study was to investigate methods of improving the therapeutic index (dose to tumor/dose to normal organs) and, hence, the efficacy of radioimmunotherapy (RIT). One method investigated was to increase the biologic response for a given radiation dose to tumor. To enhance the biologic efficacy of the dose, initial studies focused on first understanding the radiobiology of RIT irradiation and determining what role factors, such as radiation repair, repopulation, and redistribution, play in determining RIT response. In vitro studies using 4 colon carcinoma cell lines have compared the radiobiologic efficacy of low dose-rate irradiation delivered by Yttrium-90 (Y-90) with conventional high dose-rate external beam irradiation (XRT). Results suggested that one factor which determined a cell's sensitivity to Y-90 irradiation was its ability to repair radiation sublethal damage. In vivo studies demonstrated that those cell lines which were more sensitive to Y-90 irradiation in vitro were also more sensitive to RIT in vivo. For a more radioresistant line, WiDr, RIT was approximately two-fold less effective than an equivalent dose of single fraction XRT, while for a more radiosensitive line, LS174T, RIT was approximately as effective as an equivalent dose of single fraction XRT. Therefore, a tumor's response to RIT in vivo appeared to be, in part, dependent on the tumor cell's ability to repair radiation damage. Finally, studies investigated strategies at enhancing the biologic efficacy of RIT irradiation by combining RIT with chemotherapy agents that can potentially inhibit radiation repair. Agents, such as 5-fluorouracil, appeared to be synergistic with RIT irradiation n vitro and may therefore prove promising in improving the therapeutic index of RIT

  14. Knowledge evolution on effects of ionizing radiations on living being. New prospects of radiobiological researches

    International Nuclear Information System (INIS)

    The knowledge increase of all the steps going from the material radiation interaction to the risk evaluation, prevention and irradiation consequences treatment leads to new prospects in radiobiology research, such as the low doses effects. (A.B.)

  15. Press breakfast, radiobiology stakes: an European context, Thursday 25 March 2004

    International Nuclear Information System (INIS)

    The radiobiology endeavours to know the ionizing radiations effects on living systems, particular at low doses exposures. The researches in this area contribute to the elaboration of international regulation on nuclear industry. The individual radiosensitivity is an other aspect of the research in radiobiology. These studies should allow the establishing of radiation protection standards founded on a direct approach and an individual estimation of the level of acceptable dose. (N.C.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Sumida, Iori, E-mail: sumida@radonc.med.osaka-u.ac.jp [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)

    2015-07-15

    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.

  17. Fisheries Radiobiology and the Discharge of Radioactive Wastes

    International Nuclear Information System (INIS)

    In the United Kingdom authorizations to discharge radioactive wastes are granted by the Minister of Housing and Local Government, the Minister of Agriculture, Fisheries and Food, and by the Secretary of State for Scotland. The hazards arising from contamination of aquatic animals and plants concern the Department of Fisheries ; before authorizations to discharge liquid wastes have been given, the Department has made independent forecasts of permissible levels of discharge based on extensive studies carried out in its research vessels and radiobiological laboratory: for example, where fish have been affected this has meant studies of fish populations and fish migration: uptake of radioactivity by fish : public consumption of fish : commercial distribution of affected fish: L.D.50: effects of radiation on tissue, etc. In the course of such work there has been close consultation with the Atomic Energy Authority, and agreement with the Atomic Energy Authority about the safety factor to be incorporated during the first two years of discharge. During these two years, monitoring data collected by the Atomic Energy Authority and the Ministry of Agriculture, Fisheries and Food enable checks and revisions of the original estimates to be made, and at the end of that time formal authorizations, based on operating experience, are issued. (author)

  18. Feasibility of BNCT radiobiological experiments at the HYTHOR facility

    Science.gov (United States)

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

    2008-06-01

    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.

  19. Radiobiological study by using laser-driven proton beams

    Science.gov (United States)

    Yogo, A.; Sato, K.; Nishikino, M.; Mori, M.; Teshima, T.; Numasaki, H.; Murakami, M.; Demizu, Y.; Akagi, S.; Nagayama, S.; Ogura, K.; Sagisaka, A.; Orimo, S.; Nishiuchi, M.; Pirozhkov, A. S.; Ikegami, M.; Tampo, M.; Sakaki, H.; Suzuki, M.; Daito, I.; Oishi, Y.; Sugiyama, H.; Kiriyama, H.; Okada, H.; Kanazawa, S.; Kondo, S.; Shimomura, T.; Nakai, Y.; Tanoue, M.; Sugiyama, H.; Sasao, H.; Wakai, D.; Kawachi, T.; Nishimura, H.; Bolton, P. R.; Daido, H.

    2009-07-01

    Particle acceleration driven by high-intensity laser systems is widely attracting interest as a potential alternative to conventional ion acceleration, including ion accelerator applications to tumor therapy. Recent works have shown that a high intensity laser pulse can produce single proton bunches of a high current and a short pulse duration. This unique feature of laser-ion acceleration can lead to progress in the development of novel ion sources. However, there has been no experimental study of the biological effects of laser-driven ion beams. We describe in this report the first demonstrated irradiation effect of laser-accelerated protons on human lung cancer cells. In-vitro A549 cells are irradiated with a proton dose of 20 Gy, resulting in a distinct formation of γ-H2AX foci as an indicator of DNA double-strand breaks. This is a pioneering result that points to future investigations of the radiobiological effects of laser-driven ion beams. The laser-driven ion beam is apotential excitation source for time-resolved determination of hydroxyl (OH) radical yield, which will explore relationship between the fundamental chemical reactions of radiation effects and consequent biological processes.

  20. Dosimetry for radiobiological experiments using energetic heavy ions

    International Nuclear Information System (INIS)

    The availability of the Bevalac facility of energetic heavy ions with range greater than the size of small mammals makes possible the determination of the biological effects of relatively well defined high LET, whole body irradiation. With the increasing application of high-energy heavy ions in radiobiology there is a corresponding need to develop reliable techniques of both relative and absolute absorbed dose measurement. This paper describes dosimetry studies by the Health Physics Department of the Lawrence Berkeley Laboratory with activation detectors, ionization chambers, nuclear emulsion, thermoluminescent dosimeters and X-ray film. The application of these techniques to an experiment designed to study the leukemogenic effect of the whole-body irradiation of mice by 250 MeV/amu carbon ions is briefly described. Values of absorbed dose in tissue, obtained during this experiment, with a nitrogen filled ionization chamber and 7LiF thermoluminescent dosimeters are compared and shown to be in good agreement. As a result of this work a value for the average energy to produce an ion pair (W) in nitrogen by 250 MeV/amu 6+C ions of 37 +- eV was determined. Values of the efficiency of 7LiF relative to 60Co γ-rays for ions with dE/dx in the range 110-260 MeV g-1 cm2 are reported

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

    International Nuclear Information System (INIS)

    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

  2. The significance of the choice of radiobiological (NTCP) models in treatment plan objective functions

    International Nuclear Information System (INIS)

    Full text: A Clinician's discrimination between radiation therapy treatment plans is traditionally a subjective process, based on experience and existing protocols. A more objective and quantitative approach to distinguish between treatment plans is to use radiobiological or dosimetric objective functions, based on radiobiological or dosimetric models. The efficacy of models is not well understood, nor is the correlation of the rank of plans resulting from the use of models compared to the traditional subjective approach. One such radiobiological model is the Normal Tissue Complication Probability (NTCP). Dosimetric models or indicators are more accepted in clinical practice. In this study, three radiobiological models, Lyman NTCP, critical volume NTCP and relative seriality NTCP, and three dosimetric models, Mean Lung Dose (MLD) and the Lung volumes irradiated at lOGy (V|0) and 20Gy (V20), were used to rank a series of treatment plans using, harm to normal (Lung) tissue as the objective criterion. None of the models considered in this study showed consistent correlation with the Radiation Oncologists plan ranking. If radiobiological or dosimetric models are to be used in objective functions for lung treatments, based on this study it is recommended that the Lyman NTCP model be used because it will provide most consistency with traditional clinician ranking.

  3. Decoding the dynamics of cellular metabolism and the action of 3-bromopyruvate and 2-deoxyglucose using pulsed stable isotope-resolved metabolomics

    OpenAIRE

    Mudrich Epouse Dorosz, Susann Antonia; Pietzke, Matthias; Zasada, Christin

    2014-01-01

    Background Cellular metabolism is highly dynamic and continuously adjusts to the physiological program of the cell. The regulation of metabolism appears at all biological levels: (post-) transcriptional, (post-) translational, and allosteric. This regulatory information is expressed in the metabolome, but in a complex manner. To decode such complex information, new methods are needed in order to facilitate dynamic metabolic characterization at high resolution. Results Here, we descri...

  4. Decoding the dynamics of cellular metabolism and the action of 3-bromopyruvate and 2-deoxyglucose using pulsed stable isotope-resolved metabolomics

    OpenAIRE

    Pietzke, M.; Zasada, C.; Mudrich, S.; Kempa, S.

    2014-01-01

    BACKGROUND: Cellular metabolism is highly dynamic and continuously adjusts to the physiological program of the cell. The regulation of metabolism appears at all biological levels: (post-) transcriptional, (post-) translational, and allosteric. This regulatory information is expressed in the metabolome, but in a complex manner. To decode such complex information, new methods are needed in order to facilitate dynamic metabolic characterization at high resolution. RESULTS: Here, we describe pul...

  5. Radiobiological basis for setting neutron radiation safety standards

    International Nuclear Information System (INIS)

    Present neutron standards, adopted more than 20 yr ago from a weak radiobiological data base, have been in doubt for a number of years and are currently under challenge. Moreover, recent dosimetric re-evaluations indicate that Hiroshima neutron doses may have been much lower than previously thought, suggesting that direct data for neutron-induced cancer in humans may in fact not be available. These recent developments make it urgent to determine the extent to which neutron cancer risk in man can be estimated from data that are available. Two approaches are proposed here that are anchored in particularly robust epidemiological and experimental data and appear most likely to provide reliable estimates of neutron cancer risk in man. The first approach uses gamma-ray dose-response relationships for human carcinogenesis, available from Nagasaki (Hiroshima data are also considered), together with highly characterized neutron and gamma-ray data for human cytogenetics. When tested against relevant experimental data, this approach either adequately predicts or somewhat overestimates neutron tumorigenesis (and mutagenesis) in animals. The second approach also uses the Nagasaki gamma-ray cancer data, but together with neutron RBEs from animal tumorigenesis studies. Both approaches give similar results and provide a basis for setting neutron radiation safety standards. They appear to be an improvement over previous approaches, including those that rely on highly uncertain maximum neutron RBEs and unnecessary extrapolations of gamma-ray data to very low doses. Results suggest that, at the presently accepted neutron dose limit of 0.5 rad/yr, the cancer mortality risk to radiation workers is not very different from accidental mortality risks to workers in various nonradiation occupations

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2014-06-01

    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.

  7. Cellular automata

    CERN Document Server

    Codd, E F

    1968-01-01

    Cellular Automata presents the fundamental principles of homogeneous cellular systems. This book discusses the possibility of biochemical computers with self-reproducing capability.Organized into eight chapters, this book begins with an overview of some theorems dealing with conditions under which universal computation and construction can be exhibited in cellular spaces. This text then presents a design for a machine embedded in a cellular space or a machine that can compute all computable functions and construct a replica of itself in any accessible and sufficiently large region of t

  8. 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

    International Nuclear Information System (INIS)

    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)

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2014-11-15

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2012-10-23

    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.

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

    Science.gov (United States)

    Herrera, Higmar; Yañez, Elvia; López, Jesús

    2012-10-01

    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.

  12. Elucidating the cellular actions of demineralised dentine matrix extract on a clonal dental pulp stem cell population in orchestrating dental tissue repair

    OpenAIRE

    Lee, Chi P; Colombo, John S; Ayre, Wayne Nishio; Sloan, Alastair J; Waddington, Rachel J

    2015-01-01

    Bioactive growth factors identified within the extracellular matrix of dentine have been proposed roles in regulating the naturally inherent regenerative dentine formation seen in teeth in response to trauma and infection, which may also be harnessed for novel clinical treatments in augmenting mineralised tissue repair. This study examined the specific biological action of demineralised dentine matrix extract on a clonal population of dental pulp stem cells in stimulating the prerequisite sta...

  13. Skin carcinomas: Radiobiological principles, radiotherapeutic techniques and clinical management

    International Nuclear Information System (INIS)

    Purpose/Objective: The course will be divided into three major topics: (1) Review of radiobiological principles as they apply to the radiotherapeutic management of skin carcinomas; (2) review of radiotherapeutic techniques including beam qualities, beam collimation, tissue dose profiles, and the relative indications of external beam irradiation vs. brachytherapy; (3) comprehensive review of the tumor biology of skin malignancies, including malignant melanoma, and of the relative indications for radiotherapeutic and/or surgical management. (1) Review of critical data which have led to currently applied principles of time-dose-volume concepts in the radiotherapeutic management of skin carcinomas. Emphasis will be placed on the relative importance of fraction size and overall treatment time on tumor control probability and acute and late normal tissue toxicity. (2) Considering that radiotherapy in the management of skin carcinomas is often used to minimize patient disfiguration and to preserve critical body functions (e.g. eye lids) the technical aspects of radiotherapy delivery are most critical. Careful evaluation of the extent of the lesions including evaluation of their depth of invasion will determine the quality of the radiation beams, orthovoltage and low energy electrons being the most useful. Beam harding for orthovoltage beams and secondary and tertiary (skin) collimation of appropriate electron beams are critical. For more extensive and deeply invasive lesions contour-shaping through customized bolus material is essential. Equally important is the familiarity with custom shielding of critical structures, such as eyes, ears, oral cavity and central nervous system structures. Brachytherapy applications in the treatment of skin carcinomas is limited but should be considered when implants with high dose uniformity can be constructed. (3) The discussion of clinical management will start with a discussion of properties and routes of spread of the diverse

  14. Skin carcinomas: radiobiological principles, radiotherapeutic techniques and clinical management

    International Nuclear Information System (INIS)

    Purpose/Objective: The course will be divided into three major topics: (1) Review of radiobiological principles as they apply to the radiotherapeutic management of skin carcinomas; (2) review of radiotherapeutic techniques including beam qualities, beam collimation, tissue dose profiles, and the relative indications of external beam irradiation vs. brachytherapy; (3) comprehensive review of the tumor biology of skin malignancies, including malignant melanoma, and of the relative indications for radiotherapeutic and/or surgical management. (1) Review of critical data which have lead to currently applied principles of time-dose-volume concepts in the radiotherapeutic management of skin carcinomas. Emphasis will be placed on the relative importance of fraction size and overall treatment time on tumor control probability and acute and late normal tissue toxicity. (2) Considering that radiotherapy in the management of skin carcinomas is often used to minimize patient disfiguration and to preserve critical body functions (e.g. eye lids) the technical aspects of radiotherapy delivery are most critical. Careful evaluation of the extent of the lesions including evaluation of their depth of invasion will determine the quality of the radiation beams, orthovoltage and low energy electrons being the most useful. Beam harding for orthovoltage beams and secondary and tertiary (skin) collimation of appropriate electron beams are critical. For more extensive and deeply invasive lesions contour-shaping through customized bolus material is essential. Equally important is the familiarity with custom shielding of critical structures, such as eyes, ears, oral cavity and central nervous system structures. Brachytherapy applications in the treatment of skin carcinomas is limited but should be considered when implants with high dose uniformity can be constructed. (3) The discussion of clinical management will start with a discussion of tumor biological properties of the diverse malignant

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

    DEFF Research Database (Denmark)

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

    2012-01-01

    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...

  16. Radiological and Environmental Research Division, Center for Human Radiobiology. Annual report, July 1980-June 1981

    International Nuclear Information System (INIS)

    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

  17. Experimental radiotherapy and clinical radiobiology. Vol. 8, special issue 1. Proceedings

    International Nuclear Information System (INIS)

    The publication contains the abstracts of all papers and posters presented at the symposium. The headings were as follows: Radiobiology of the lung, mediation of radiation damage in the lung, clinical studies, future clinical directions, as well as documentation and management. (MG)

  18. Emerging issues in radiobiology and cancer research - the impact of non-targeted effects

    International Nuclear Information System (INIS)

    Since the acceptance that non-targeted effects (NTE) can be measured in unirradiated cells or distant progeny of irradiated cells, the discussion has developed about the relevance of these effects for radiobiology and radiation protection since they increase the complexity of the radiation response and allow for outcomes which are not as predictable as they were under the 'old rules'. Specific examples will be presented and analysed which challenge accepted paradigms. 1. Data show that bystander mechanisms are either on or off in cells and that the 'on' threshold appears to be at a very low dose (mGy range). 2. Data suggest that adaptive responses are induced not only in neighbouring cells but in organisms which receive bystander signals. 3. Data show that chronic exposures to alpha or gamma irradiation lead to complex responses in organisms which can be adaptive and protective. 4. Evidence suggests that mixed contaminant exposures which include radiation can have sub-additive or synergistic effects. A key consequence of findings in NTE biology is that at any given level of organization, from gene to ecosystem - communication of stress signals and heritability of stress adaptations provide the bridges linking one hierarchical level to the next and enable the rapid propagation of change triggered by stress at one level, resulting in change at a higher (or lower?) level. Evolution could thus be regulated through communicated signals between cells, individuals, and populations which control and optimize responses coordinating the emergence of exquisitely tuned systems which can adapt rapidly to micro or macro environmental change. A current view of cancer is that it is a 'systems level' disease which can not be understood or treated by looking at individual genes or pathways in the traditional way. Rather, a system approach is required with looks at the environment at both cellular and organismal levels to understand what has been perturbed. We suggest that bystander

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2006-07-01

    -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)

  20. Cellular Telephone

    Institute of Scientific and Technical Information of China (English)

    杨周

    1996-01-01

    Cellular phones, used in automobiles, airliners, and passenger trains, are basically low-power radiotelephones. Calls go through radio transmitters that are located within small geographical units called cells. Because each cell’s signals are too weak to interfere with those of other cells operating on the same fre-

  1. Paul Scherrer Institut annual report 1996. Annex II: PSI life sciences and Institute for Medical Radiobiology Newsletter 1996

    International Nuclear Information System (INIS)

    This annex to the PSI Annual Report 1996 reports on the progress achieved by the PSI Department II during 1996 in the fields of radiation medicine, radiopharmacy, radiation hygiene, positron emission tomography and medical radiobiology. figs., tab., refs

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

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-09-01

    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.

  4. Report of the Van de Graaff Group: radiobiology

    International Nuclear Information System (INIS)

    There exists a need for relevant information on the molecular and cellular processes induced by radiation. In this project several aspects of the problem of developing a human tumor model and growing human cells in culture, have been investigated. Human embryo fibroblasts were grown in 1000 mm plastic Petri dishes in a suitable nutrient medium, supplemented with 10% fetal calf serum and antibiotics. The following series of mutagens were utilized: ultra-violet radiation, chemical carcinogens and nucleosite analogues, such as 5-azacytidine (aza C). Some of the treated human fibroblasts were also examined by electron microscopy and the reverse transcriptase assay

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

    Science.gov (United States)

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

    1993-01-01

    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.

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

    International Nuclear Information System (INIS)

    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

  7. Radiobiological impact of dose calculation algorithms on biologically optimized IMRT lung stereotactic body radiation therapy plans

    OpenAIRE

    Liang, X.; Penagaricano, J.; Zheng, D.; Morrill, S.; Zhang, X; Corry, P.; Griffin, R. J.; Han, E. Y.; Hardee, M.; Ratanatharathom, V.

    2016-01-01

    Background The aim of this study is to evaluate the radiobiological impact of Acuros XB (AXB) vs. Anisotropic Analytic Algorithm (AAA) dose calculation algorithms in combined dose-volume and biological optimized IMRT plans of SBRT treatments for non-small-cell lung cancer (NSCLC) patients. Methods Twenty eight patients with NSCLC previously treated SBRT were re-planned using Varian Eclipse (V11) with combined dose-volume and biological optimization IMRT sliding window technique. The total dos...

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

    Science.gov (United States)

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

    2015-11-01

    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

  9. Heavy Charged Particle Radiobiology: Using Enhanced Biological Effectiveness and Improved Beam Focusing to Advance Cancer Therapy

    OpenAIRE

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

    2011-01-01

    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 facilitie...

  10. Installation of a flow cytometry facility and some applications in radiobiology

    International Nuclear Information System (INIS)

    Flow cytometry has enormous potential in many areas of experimental pathology. Details of the installation and commissioning of a flow cytometer at the Harwell Laboratory are described. Following an explanation of the principles of flow cytometry, several applications to specific problems in radiobiology are discussed. Also included are results of some preliminary studies with the Harwell flow cytometer on samples such as blood, bone marrow, macrophages and cell cultures, and a discussion of future applications. (author)

  11. Radiobiological work using a negative pion beam at the Rutherford Laboratory 1971-76

    International Nuclear Information System (INIS)

    The subject is discussed in two sections: physics experiments (including, inter alia, dose measurement, LET distribution, radiation products of spallation); radiobiological studies (including separate reports as follows: review of experimental programme; some in vivo effects of negative pions in mice; survival and recovery of Hela cells in vitro; negative pion dose-response curves for frozen Hela cells; response of vicia faba to irradiation with negative pions; pion experiments with chromosome aberrations). (U.K.)

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

    Science.gov (United States)

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

    2012-08-21

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1985-01-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Claesson, Kristina

    2011-05-15

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Samantha, E-mail: Samantha.warren@oncology.ox.ac.uk [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)

    2014-10-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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: armando.astudillo@inin.gob.mx [Hospital Medica Sur, Puente de Piedra 150, Col. Toriello Guerra, 14050 Tlalpan, Mexico D. F. (Mexico)

    2015-10-15

    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)

  17. Extrapolation ionisation chamber measurements on beta-emitting sources produced for the CEGB collaborative radiobiology programme

    International Nuclear Information System (INIS)

    This report describes the structure and application of an extrapolation ionisation chamber used for measuring dose-rates from plane and point beta-emitting sources. These measurements form the basis of the dosimetry for a collaborative radiobiological study of skin to study both stochastic and non-stochastic effects. A small sample from the wide range of measurements undertaken in the programme has been selected to illustrate the procedures involved. The extrapolation chamber is currently being automated and it is intended that this report should provide a source reference to the basis of the measurements made between 1977-86. (author)

  18. Research in radiobiology. Annual report of work in progress in the Internal Irradiation Program

    International Nuclear Information System (INIS)

    Survival data on 160 nonirradiated control beagles of the University of Utah's Radiobiology Laboratory were analyzed. The animals died during a period from 1958 into 1979. The average age at death of animals which died during the 1958 to 1965 interval was significantly less than that of those whose deaths occurred in the 1965 to 1979 interval. The best estimate for average age at death for Super-Selected nonirradiated control beagles of the colony is 4864 +- 901 days. The Super-Selected dogs excluded those dying because of epilepsy, lymphosarcoma, lymphoma or accidents, and also excluded all dogs dying before 1966

  19. Environmental Research Division annual report: Center for Human Radiobiology, July 1982-June 1983

    International Nuclear Information System (INIS)

    This is the fourteenth Annual Report of the Center for Human Radiobiology. New cases of bone cancer and carcinoma of head sinuses are occurring at a rate of about one per year in patients who acquired radium burdens 50 to 60 years ago. Several papers deal with dosimetry of alpha-emitting radionuclides in man, in animals, or in the environment. The report concludes with an appendix containing data on the exposure of 2312 persons whose radium content has been determined and an appendix listing the classical radium-related malignancies (osteosarcomas and carcinomas of the paranasal sinuses and mastoid)

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

    Science.gov (United States)

    Esposito, J; Rosi, G; Agosteo, S

    2007-01-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-07-15

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    2016-05-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

    CHEN Liang; YAN Jingwen; JIANG Shiping; YU Yang

    2009-01-01

    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.

  4. Preparatory study of a ground-based space radiobiology program in Europe

    Science.gov (United States)

    Durante, M.; Kraft, G.; O'Neill, P.; Reitz, G.; Sabatier, L.; Schneider, U.

    Space radiation has long been acknowledged as a potential showstopper for long duration manned interplanetary missions. Our knowledge of biological effects of cosmic radiation in deep space is almost exclusively derived from ground-based accelerator experiments with heavy ions in animal or in vitro models. In an effort to gain more information on space radiation risk and to develop countermeasures, NASA initiated several years ago a Space Radiation Health Program, which is currently supporting biological experiments performed at the Brookhaven National Laboratory. Accelerator-based radiobiology research in the field of space radiation research is also under way in Russia and Japan. The European Space Agency (ESA) has recently established an ambitious exploration program (AURORA), and within this program it has been decided to include a space radiation research program. Europe has a long tradition in radiobiology research at accelerators, generally focussing on charged-particle cancer therapy. This expertise can be adapted to address the issue of space radiation risk. To support research in this field in Europe, ESA issued a call for tender in 2005 for a preliminary study of investigations on biological effects of space radiation (IBER). This study will provide guidance on future ESA-supported activities in space radiation research by identifying the most appropriate European accelerator facilities to be targeted for cooperation, and by drafting a roadmap for future research activities. The roadmap will include a prioritisation of research topics, and a detailed proposal for experimental campaigns for the following 5 10 years.

  5. The effect of dose escalation on gastric toxicity when treating lower oesophageal tumours: a radiobiological investigation

    International Nuclear Information System (INIS)

    Using radiobiological modelling to estimate normal tissue toxicity, this study investigates the effects of dose escalation for concurrent chemoradiation therapy (CRT) in lower third oesophageal tumours on the stomach. 10 patients with lower third oesophageal cancer were selected from the SCOPE 1 database (ISCRT47718479) with a mean planning target volume (PTV) of 348 cm3. The original 3D conformal plans (50Gy3D) were compared to newly created RapidArc plans of 50GyRA and 60GyRA, the latter using a simultaneous integrated boost (SIB) technique using a boost volume, PTV2. Dose-volume metrics and estimates of normal tissue complication probability (NTCP) were compared. There was a significant increase in NTCP of the stomach wall when moving from the 50GyRA to the 60GyRA plans (11–17 %, Wilcoxon signed rank test, p = 0.01). There was a strong correlation between the NTCP values of the stomach wall and the volume of the stomach wall/PTV 1 and stomach wall/PTV2 overlap structures (R = 0.80 and R = 0.82 respectively) for the 60GyRA plans. Radiobiological modelling suggests that increasing the prescribed dose to 60Gy may be associated with a significantly increased risk of toxicity to the stomach. It is recommended that stomach toxicity be closely monitored when treating patients with lower third oesophageal tumours with 60Gy

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yimei, E-mail: yhuang2@hfhs.org; 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)

    2015-10-15

    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

  8. Literature study of the radiobiological parameters of Caesium-137 required for evaluating internal irradiation doses as a function of age

    International Nuclear Information System (INIS)

    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)

  9. 77 FR 68155 - The Armed Forces Radiobiology Research Institute TRIGA Reactor: Facility Operating License No. R-84

    Science.gov (United States)

    2012-11-15

    ... NRC's E-Filing rule (72 FR 49139; August 28, 2007). The E-Filing process requires participants to... filing requirements of the NRC's E-Filing Rule (72 FR 49139; August 28, 2007) apply to appeals of NRC... COMMISSION The Armed Forces Radiobiology Research Institute TRIGA Reactor: Facility Operating License No....

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

    Energy Technology Data Exchange (ETDEWEB)

    1982-03-01

    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)

  11. Proton Radiobiology

    OpenAIRE

    Francesco Tommasino; Marco Durante

    2015-01-01

    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...

  12. Proton Radiobiology

    Directory of Open Access Journals (Sweden)

    Francesco Tommasino

    2015-02-01

    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.

  13. Aging, cellular senescence, and cancer.

    Science.gov (United States)

    Campisi, Judith

    2013-01-01

    For most species, aging promotes a host of degenerative pathologies that are characterized by debilitating losses of tissue or cellular function. However, especially among vertebrates, aging also promotes hyperplastic pathologies, the most deadly of which is cancer. In contrast to the loss of function that characterizes degenerating cells and tissues, malignant (cancerous) cells must acquire new (albeit aberrant) functions that allow them to develop into a lethal tumor. This review discusses the idea that, despite seemingly opposite characteristics, the degenerative and hyperplastic pathologies of aging are at least partly linked by a common biological phenomenon: a cellular stress response known as cellular senescence. The senescence response is widely recognized as a potent tumor suppressive mechanism. However, recent evidence strengthens the idea that it also drives both degenerative and hyperplastic pathologies, most likely by promoting chronic inflammation. Thus, the senescence response may be the result of antagonistically pleiotropic gene action. PMID:23140366

  14. 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

    CERN Multimedia

    2002-01-01

    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

  15. Hypo-fractionated treatment in radiotherapy: radio-biological models Tcp and NTCP

    International Nuclear Information System (INIS)

    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)

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

    Science.gov (United States)

    Mavroidis, Panayiotis; Costa Ferreira, Brigida; Shi, Chengyu; Lind, Bengt K.; Papanikolaou, Nikos

    2007-07-01

    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 ({\\bar{\\bar{D}}}) is applied together with the complication-free tumour control probability (P+). 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 {\\bar{\\bar{D}}} as the common prescription point of the treatment plans and plotting the tissue response probabilities versus {\\bar{\\bar{D}}} for a range of prescription doses

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

    Science.gov (United States)

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

    2011-06-01

    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.

  18. AFRRI (Armed Forces Radiobiology Research Institute) reports, April-June 1985. Technical report

    Energy Technology Data Exchange (ETDEWEB)

    1985-01-01

    The following titles are included in this collection of reprints: Presence of a high-affinity Ca(s+) - and Mg(2+) - dependent ATPase in rat peritoneal mast-cell membranes; Prostanoid production by lipopolysaccharide stimulated Kupffer cells; Antihistamines block radiation-induced increased intestinal blood flow in canines; WR-2721 inhibition of radiation-induced prostaglandin excretion in rats; Effects of mixed neutron-gamma total-body irradiation on physical activity performance of rhesus monkeys; Immunologic and hematologic perturbations in models of combined injury; Hematopoiesis in conventional mice after wound trauma; Carrier generation recombination, and transport in organic crystals; Energy transfer and molecular weight effects on polymer luminescence. Keywords: Radiobiology; Military research.

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

    Science.gov (United States)

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

    2011-06-01

    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. PMID:21376738

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

    Science.gov (United States)

    Barahona, Ana

    2015-01-01

    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.

  1. Radiobiological research for improving cancer therapy in India: rationale, problems and prospects

    International Nuclear Information System (INIS)

    Cancer is emerging as a very important health hazard in India. According to recent studies by the Indian Council of Medical Research, about 2.25 million patients are presently suffering from different types of cancer in India. Approximately one million new cases are diagnosed, and nearly 0.3 million deaths occur every year on account of this disease. About 2/3rd of the cancers are at an advanced stage at the time of diagnosis. However, the allocation of funds for healthcare in India to support the research efforts for developing more potent radio-chemotherapy protocols for cancer treatment is too little. Studies by the W.H.O. have estimated that less developed countries including India use less than 5% of world resources destined for cancer control. It follows from the above discussions that it is imperative to further encourage and diversify the radiobiological research in India. This can be achieved by creating radiobiological research facilities, mainly in all the cancer centers and post graduate medical institutions, and further expanding the upcoming laboratories in the universities such as Bikaner. Collaborative research programs between laboratories at different centers could facilitate systematic evaluation of various pharmacological agents and neutraceuticals for potential application for treatment of different cancers. Our studies on combination of radiation with temozolomide and certain adjuvants with selective effects on brain tumour cells will be very briefly discussed in this presentation. Finally the possible administrative set up and multi dimensional collaborations for cost effective utilization of existing resources to further augment radiation biology research will also be discussed

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

    Science.gov (United States)

    Cucinotta, Francis; Saganti, Premkumar; Cacao, Eliedonna

    2016-07-01

    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.

  3. Cellular: Toward personal communications

    Science.gov (United States)

    Heffernan, Stuart

    1991-09-01

    The cellular industry is one of the fastest growing segment of the telecommunications industry. With an estimated penetration rate of 20 percent in the near future, cellular is becoming an ubiquitous telecommunications service in the U.S. In this paper we will examine the major advancements in the cellular industry: customer equipment, cellular networks, engineering tools, customer support, and nationwide seamless service.

  4. Radiation-induced cardiac damage in early left breast cancer patients: Risk factors, biological mechanisms, radiobiology, and dosimetric constraints

    International Nuclear Information System (INIS)

    Today there is general awareness of the potential damage to the heart in left-sided (more than in right-sided) breast cancer radiotherapy (RT). Historical changes in tumor and heart doses are presented here along with the impact of different RT techniques and volumes. Individual and pharmacological risk factors are also examined with respect to radiation damage. The biological mechanisms of harm are only partially understood, such as the radiobiology of heart damage due to the presence of various radiosensitive structures and their topographic heterogeneity. Furthermore, individual variability may expose patients to higher or lower risks of late cardiac damage or death. Damage mechanisms and radiobiological characteristics in heart irradiation are presented in relation to dosimetric and biological parameters.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-12-31

    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)

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

    International Nuclear Information System (INIS)

    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.)

  7. Relationships Between Rectal Wall Dose-Volume Constraints and Radiobiologic Indices of Toxicity for Patients With Prostate Cancer

    International Nuclear Information System (INIS)

    Purpose: The purpose of this article was to investigate how exceeding specified rectal wall dose-volume constraints impacts on the risk of late rectal bleeding by using radiobiologic calculations. Methods and Materials: Dose-volume histograms (DVH) of the rectal wall of 250 patients with prostate cancer were analyzed. All patients were treated by three-dimensional conformal radiation therapy, receiving mean target doses of 80 Gy. To study the main features of the patient population, the average and the standard deviation of the distribution of DVHs were generated. The mean dose , generalized equivalent uniform dose formulation (gEUD), modified equivalent uniform dose formulation (mEUD)0, and normal tissue complication probability (NTCP) distributions were also produced. The DVHs set was then binned into eight classes on the basis of the exceeding or the fulfilling of three dose-volume constraints: V40 = 60%, V50 = 50%, and V70 = 25%. Comparisons were made between them by , gEUD, mEUD0, and NTCP. Results: The radiobiologic calculations suggest that late rectal toxicity is mostly influenced by V70. The gEUD and mEUD0 are risk factors of toxicity always concordant with NTCP, inside each DVH class. The mean dose, although a reliable index, may be misleading in critical situations. Conclusions: Both in three-dimensional conformal radiation therapy and particularly in intensity-modulated radiation therapy, it should be known what the relative importance of each specified dose-volume constraint is for each organ at risk. This requires a greater awareness of radiobiologic properties of tissues and radiobiologic indices may help to gradually become aware of this issue

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

    OpenAIRE

    Beyreuther, Elke

    2010-01-01

    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 t...

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

    Science.gov (United States)

    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

  10. Radiobiological evaluation of intensity modulated radiation therapy treatments of patients with head and neck cancer: A dual-institutional study

    Directory of Open Access Journals (Sweden)

    G Narayanasamy

    2015-01-01

    Full Text Available In clinical practice, evaluation of clinical efficacy of treatment planning stems from the radiation oncologist's experience in accurately targeting tumors, while keeping minimal toxicity to various organs at risk (OAR involved. A more objective, quantitative method may be raised by using radiobiological models. The purpose of this work is to evaluate the potential correlation of OAR-related toxicities to its radiobiologically estimated parameters in simultaneously integrated boost (SIB intensity modulated radiation therapy (IMRT plans of patients with head and neck tumors at two institutions. Lyman model for normal tissue complication probability (NTCP and the Poisson model for tumor control probability (TCP models were used in the Histogram Analysis in Radiation Therapy (HART analysis. In this study, 33 patients with oropharyngeal primaries in the head and neck region were used to establish the correlation between NTCP values of (a bilateral parotids with clinically observed rates of xerostomia, (b esophagus with dysphagia, and (c larynx with dysphagia. The results of the study indicated a strong correlation between the severity of xerostomia and dysphagia with Lyman NTCP of bilateral parotids and esophagus, respectively, but not with the larynx. In patients without complications, NTCP values of these organs were negligible. Using appropriate radiobiological models, the presence of a moderate to strong correlation between the severities of complications with NTCP of selected OARs suggested that the clinical outcome could be estimated prior to treatment.

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

    Science.gov (United States)

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

    2013-04-01

    For many years the linear-quadratic (LQ) model has been widely used to describe the effects of total dose and dose per fraction at low-to-intermediate doses in conventional fractionated radiotherapy. Recent advances in stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT) have increased the interest in finding a reliable cell survival model, which will be accurate at high doses, as well. Different models have been proposed for improving descriptions of high dose survival responses, such as the Universal Survival Curve (USC), the Kavanagh-Newman (KN) and several generalizations of the LQ model, e.g. the Linear-Quadratic-Linear (LQL) model and the Pade Linear Quadratic (PLQ) model. The purpose of the present study is to compare a number of models in order to find the best option(s) which could successfully be used as a fractionation correction method in SRT. In this work, six independent experimental data sets were used: CHOAA8 (Chinese hamster fibroblast), H460 (non-small cell lung cancer, NSLC), NCI-H841 (small cell lung cancer, SCLC), CP3 and DU145 (human prostate carcinoma cell lines) and U1690 (SCLC). By detailed comparisons with these measurements, the performance of nine different radiobiological models was examined for the entire dose range, including high doses beyond the shoulder of the survival curves. Using the computed and measured cell surviving fractions, comparison of the goodness-of-fit for all the models was performed by means of the reduced χ (2)-test with a 95% confidence interval. The obtained results indicate that models with dose-independent final slopes and extrapolation numbers generally represent better choices for SRT. This is especially important at high doses where the final slope and extrapolation numbers are presently found to play a major role. The PLQ, USC and LQL models have the least number of shortcomings at all doses. The extrapolation numbers and final slopes of these models do not depend on dose. Their asymptotes

  12. Dosimetric measurements and radiobiological consequences of radioimmunotherapy in tumor bearing mice

    International Nuclear Information System (INIS)

    With the development of the hybridoma technology, the production of highly specific tumor associated monoclonal antibodies has provided new optimism for the adjuvant delivery of therapeutic radiation doses via radioimmunotherapy. The authors have used a modified form of the well-established TL dosimetry technology to measure the dose resulting from radioimmunotherapy experiments in tumor bearing mice. Their laboratory has designed and tested a miniature CaSO4:D TLD which fits conveniently inside a 20 gauge needle for the direct implantation of the dosimeter in an animal model undergoing radiolabeled antibody therapy. Direct measurement of absorbed dose from beta and gamma radiation in the animals may be obtained upon removal of the dosimeter at animal sacrifice or by surgery. This absorbed dose data may then be related to antibody affinity and localization data obtained by serial biodistribution studies. Using p96.5 melanoma antibody with a Brown Tumor Model in athymic mice, localization indices measured in the range of 2 to 4 and scored 4 to 7 days post antibody injection, yielded a tumor dose/whole body dose ratio of 1.10 +/- 0.04 (no enhancement). The dose to liver showed marker time-dependent enhancement relative to the whole body, however. An outline of suggested control radiobiological experiments to be performed in conjunction with radioimmunotherapy experiments has been included in order to provide comparative dose response data. 11 references, 14 figures, 3 tables

  13. Radiobiological modeling of interplay between accelerated repopulation and altered fractionation schedules in head and neck cancer

    Directory of Open Access Journals (Sweden)

    Marcu Loredana

    2009-01-01

    Full Text Available Head and neck cancer represents a challenge for radiation oncologists due to accelerated repopulation of cancer cells during treatment. This study aims to simulate, using Monte Carlo methods, the response of a virtual head and neck tumor to both conventional and altered fractionation schedules in radiotherapy when accelerated repopulation is considered. Although clinical trials are indispensable for evaluation of novel therapeutic techniques, they are time-consuming processes which involve many complex and variable factors for success. Models can overcome some of the limitations encountered by trials as they are able to simulate in less complex environment tumor cell kinetics and dynamics, interaction processes between cells and ionizing radiation and their outcome. Conventional, hyperfractionated and accelerated treatment schedules have been implemented in a previously developed tumor growth model which also incorporates tumor repopulation during treatment. This study focuses on the influence of three main treatment-related parameters, dose per fraction, inter fraction interval and length of treatment gap and gap timing based on RTOG trial data on head and neck cancer, on tumor control. The model has shown that conventionally fractionated radiotherapy is not able to eradicate the stem population of the tumor. Therefore, new techniques such as hyperfractionated/ accelerated radiotherapy schedules should be employed. Furthermore, the correct selection of schedule-related parameters (dose per fraction, time between fractions, treatment gap scheduling is crucial in overcoming accelerated repopulation. Modeling of treatment regimens and their input parameters can offer better understanding of the radiobiological interactions and also treatment outcome.

  14. Radiobiological modeling of interplay between accelerated repopulation and altered fractionation schedules in head and neck cancer.

    Science.gov (United States)

    Marcu, Loredana G; Bezak, Eva

    2009-10-01

    Head and neck cancer represents a challenge for radiation oncologists due to accelerated repopulation of cancer cells during treatment. This study aims to simulate, using Monte Carlo methods, the response of a virtual head and neck tumor to both conventional and altered fractionation schedules in radiotherapy when accelerated repopulation is considered. Although clinical trials are indispensable for evaluation of novel therapeutic techniques, they are time-consuming processes which involve many complex and variable factors for success. Models can overcome some of the limitations encountered by trials as they are able to simulate in less complex environment tumor cell kinetics and dynamics, interaction processes between cells and ionizing radiation and their outcome. Conventional, hyperfractionated and accelerated treatment schedules have been implemented in a previously developed tumor growth model which also incorporates tumor repopulation during treatment. This study focuses on the influence of three main treatment-related parameters, dose per fraction, inter fraction interval and length of treatment gap and gap timing based on RTOG trial data on head and neck cancer, on tumor control. The model has shown that conventionally fractionated radiotherapy is not able to eradicate the stem population of the tumor. Therefore, new techniques such as hyperfractionated/ accelerated radiotherapy schedules should be employed. Furthermore, the correct selection of schedule-related parameters (dose per fraction, time between fractions, treatment gap scheduling) is crucial in overcoming accelerated repopulation. Modeling of treatment regimens and their input parameters can offer better understanding of the radiobiological interactions and also treatment outcome.

  15. Postoperative radiotherapy in DBCG during 30 years. Techniques, indications and clinical radiobiological experience

    Energy Technology Data Exchange (ETDEWEB)

    Overgaard, Marie; Juul Christensen, Jens (Dept. of Oncology and Dept. of Medical Physics, Aarhus Univ. Hospital, Aarhus (Denmark))

    2008-05-15

    During the time period 1977-2007 postoperative radiotherapy in DBCG has varied considerably with regard to techniques and indications together with changes in the extent of surgery and adjuvant systemic therapy. The radiation treatment has been developed on the basis of clinical, radiophysical and radiobiological principles, encompassing also practical problems such as available equipment in the different centres and at times lack of sufficient machine capacity. The paper focus especially on the comprehensive work done prior to the DBCG 82 b and c studies, in order to optimize radiotherapy in all aspects prior to the evaluation of the efficacy of this treatment modality. The results from these trials did succeed in clear evidence that radiotherapy has an important role in the multidisciplinary treatment of early breast cancer. In parallel to these studies a new and challenging use of radiotherapy after breast conserving surgery was evaluated in the DBCG TM 82 protocol. The experience obtained with different techniques in this study formed the basis for the current principles of radiotherapy after lumpectomy. Reduction of radiation related morbidity has been a major issue for the DBCG radiotherapy group, and in this aspect several studies, including quality control visits, have been carried out to make the relevant modifications and to evaluate deviations from the guidelines between the centres. The background for the changes in radiotherapy is described for each of the programme periods as well as future perspectives which will include further refinements of the target and adjustments of dose and fractionation in selected patients

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

    Science.gov (United States)

    Downey, Danielle; Chun, Stacey; Follett, Peter

    2015-06-01

    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. PMID:26470205

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2015-12-15

    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. Environmental Research Division annual report: Center for Human Radiobiology, July 1983-June 1984. Part 2

    International Nuclear Information System (INIS)

    Epidemiological studies of the late effects of internal radium in man, and mechanistic investigations of those effects, have continued. The current status of the study is summarized. An experimental technique for preparing thin sections of bone and the application of that technique in studying the comparative distribution of radium and plutonium are described. Radiological dental changes due to radium in man and dog are compared. Survival of human fibroblasts irradiated with alpha particles in vitro was found to be higher when the average LET was higher. In the study of the late effects of thorium in man, the relative activities of the daughter products in the lung have been determined spectrometrically in vivo. The exhalation of thoron in these persons has been investigated in relation to lung burden of thorium and to personal factors such as smoking, age, and weight. The administration of two isotopes to large mammals has been used to demonstrate that the metabolism of plutonium is independent of route of entry and to determine the gastrointestinal absorption of plutonium. The effect of thermoluminescence on a scintillation radon counting system has been investigated quantitatively. Data on the exposure of 88 persons to radium were added to the data base, bringing the total to 2400 radium cases under study by the Center for Human Radiobiology. Separate abstracts were prepared for individual papers

  19. Neutron flux characterisation of the Pavia TRIGA Mark II research reactor for radiobiological and microdosimetric applications.

    Science.gov (United States)

    Alloni, D; Prata, M; Salvini, A; Ottolenghi, A

    2015-09-01

    Nowadays the Pavia TRIGA reactor is available for national and international collaboration in various research fields. The TRIGA Mark II nuclear research reactor of the Pavia University offers different in- and out-core neutron irradiation channels, each characterised by different neutron spectra. In the last two years a campaign of measurements and simulations has been performed in order to guarantee a better characterisation of these different fluxes and to meet the demands of irradiations that require precise information on these spectra in particular for radiobiological and microdosimetric studies. Experimental data on neutron fluxes have been collected analysing and measuring the gamma activity induced in thin target foils of different materials irradiated in different TRIGA experimental channels. The data on the induced gamma activities have been processed with the SAND II deconvolution code and finally compared with the spectra obtained with Monte Carlo simulations. The comparison between simulated and measured spectra showed a good agreement allowing a more precise characterisation of the neutron spectra and a validation of the adopted method. PMID:25958412

  20. Water versus DNA: new insights into proton track-structure modelling in radiobiology and radiotherapy

    International Nuclear Information System (INIS)

    Water is a common surrogate of DNA for modelling the charged particle-induced ionizing processes in living tissue exposed to radiations. The present study aims at scrutinizing the validity of this approximation and then revealing new insights into proton-induced energy transfers by a comparative analysis between water and realistic biological medium. In this context, a self-consistent quantum mechanical modelling of the ionization and electron capture processes is reported within the continuum distorted wave-eikonal initial state framework for both isolated water molecules and DNA components impacted by proton beams. Their respective probability of occurrence—expressed in terms of total cross sections—as well as their energetic signature (potential and kinetic) are assessed in order to clearly emphasize the differences existing between realistic building blocks of living matter and the controverted water-medium surrogate. Consequences in radiobiology and radiotherapy will be discussed in particular in view of treatment planning refinement aiming at better radiotherapy strategies. (paper)

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

    Science.gov (United States)

    Downey, Danielle; Chun, Stacey; Follett, Peter

    2015-06-01

    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.

  2. Radiobiological investigation on the ray induced sterilization of east worm (Grapholita molesta busc., lepidoptera:tortricidae)

    International Nuclear Information System (INIS)

    Results of radiobiological investigations on the sterilizing effect of the ionizing radiation, used to treat pupae and imagines of the oriental fruit moth (G. molesta) are reported. The irradiation is realized with gamma rays (60Co) of 12-13 Gy/s (±5%). The parameters of the induced sterility are determined differently for male and female specimen. The sterilizing effect of gamma radiation on male specimen irradiated as pupae and adults results in lethal spermatozoa mutations. The functional interrelation (dose-dominant lethals) is described by curves of a mixed type, consisting of a linear and non-linear component. The established dynamics in the frequency of the mutations in the dose range suggests that the optimum sterilizing ray doses are in the range 400-500 Gy. Doses below 500 Gy (pupae) and 450 Gy (imago) do not reduce considerably the life of the male butterflies. The sterilizing effect on the female specimen after pupae and imagines irradiation is due to dominant lethal mutations in the oocytes. The interrelation (dose-dominant lethals) is described by curves of sigmoid configuration. The absolutely sterilizing dose for both ontogenic stages is 150 Gy. The irradiation of the female specimen causes partial sterility along with the induction of dominant lethals in the ovules

  3. Water versus DNA: new insights into proton track-structure modelling in radiobiology and radiotherapy.

    Science.gov (United States)

    Champion, C; Quinto, M A; Monti, J M; Galassi, M E; Weck, P F; Fojón, O A; Hanssen, J; Rivarola, R D

    2015-10-21

    Water is a common surrogate of DNA for modelling the charged particle-induced ionizing processes in living tissue exposed to radiations. The present study aims at scrutinizing the validity of this approximation and then revealing new insights into proton-induced energy transfers by a comparative analysis between water and realistic biological medium. In this context, a self-consistent quantum mechanical modelling of the ionization and electron capture processes is reported within the continuum distorted wave-eikonal initial state framework for both isolated water molecules and DNA components impacted by proton beams. Their respective probability of occurrence-expressed in terms of total cross sections-as well as their energetic signature (potential and kinetic) are assessed in order to clearly emphasize the differences existing between realistic building blocks of living matter and the controverted water-medium surrogate. Consequences in radiobiology and radiotherapy will be discussed in particular in view of treatment planning refinement aiming at better radiotherapy strategies. PMID:26406277

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

    International Nuclear Information System (INIS)

    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. (author)

  5. Radiobiology at ultra-high dose rates employing laser-driven ions

    Science.gov (United States)

    Hanton, F.; Doria, D.; Kakolee, K. F.; Kar, S.; Litt, S. K.; Fiorini, F.; Ahmed, H.; Green, S.; Jeynes, J. C. G.; Kavanagh, J.; Kirby, D.; Kirkby, K. J.; Lewis, C. L.; Merchant, M. J.; Nersisyan, G.; Prasad, R.; Prise, K.; Schettino, G.; Zpef, M.; Borghesi, M.

    2013-05-01

    The potential that laser based particle accelerators offer to solve sizing and cost issues arising with conventional proton therapy has generated great interest in the understanding and development of laser ion acceleration, and in investigating the radiobiological effects induced by laser accelerated ions. Laser-driven ions are produced in bursts of ultra-short duration resulting in ultra-high dose rates, and an investigation at Queen's University Belfast was carried out to investigate this virtually unexplored regime of cell rdaiobiology. This employed the TARANIS terawatt laser producing protons in the MeV range for proton irradiation, with dose rates exceeding 109 Gys-1 on a single exposure. A clonogenic assay was implemented to analyse the biological effect of proton irradiation on V79 cells, which, when compared to data obtained with the same cell line irradiated with conventionally accelerated protons, was found to show no significant difference. A Relative Biological effectiveness of 1.4+/-0.2 at 10 % Survival Fraction was estimated from a comparison with a 225 kVp X-ray source.

  6. Decontamination activities at the National Institute of Oncology and Radiobiology in Havana, Cuba

    International Nuclear Information System (INIS)

    The National Institute of Oncology and Radiobiology had a facility contaminated with 137Cs. The contamination was produced by a leaking source stored in the place. First decontamination work was performed in 1988. Some highly contaminated floor tiles and other contaminated items were removed. Spent sealed sources stored in the facility were collected. The facility was closed because of the remaining contamination. As the Regulatory Body allowed the unrestricted use of the facility, decontamination and decommissioning were needed. D and D activities were requested to the CPHR. Contamination surveys conducted in 1999 confirmed the extent of contamination with 137Cs. Items inside the contaminated area were carefully monitored and segregated. Six Radium sources were recovered. Physical and chemical methods of decontamination were used. For different reasons, the requirements established by the Regulatory Authority for decommissioning could not be achieved, and therefore the facility could not be released from regulatory control. A Radiological Status Report was done explaining the high cost of decontamination according to the established clearance levels. New alternatives were then proposed for decommissioning of this facility. (author)

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

    Science.gov (United States)

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

    2014-02-01

    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.

  8. Biological effects of embedded depleted uranium (DU). Summary of Armed Forces Radiobiology Research Institute research

    International Nuclear Information System (INIS)

    The Persian Gulf War resulted in injuries of US Coalition personnel by fragments of depleted uranium (DU). Fragments not immediately threatening the health of the individuals were allowed to remain in place, based on long-standing treatment protocols designed for other kinds of metal shrapnel injuries. However, questions were soon raised as to whether this approach is appropriate for a metal with the unique radiological and toxicological properties of DU. The Armed Forces Radiobiology Research Institute (AFRRI) is investigating health effects of embedded fragments of DU to determine whether current surgical fragment removal policies remain appropriate for this metal. These studies employ rodents implanted with DU pellets as well as cultured human cells exposed to DU compounds. Results indicate uranium from implanted DU fragments distributed to tissues far-removed from implantation sites, including bone, kidney, muscle, and liver. Despite levels of uranium in the kidney that were nephrotoxic after acute exposure, no histological or functional kidney toxicity was observed. However, results suggest the need for further studies of long-term health impact, since DU was found to be mutagenic, and it transformed human osteoblast cells to a tumorigenic phenotype. It also altered neurophysiological parameters in rat hippocampus, crossed the placental barrier, and entered fetal tissue. This report summarizes AFRRI's depleted uranium research to date

  9. Neutron flux characterisation of the Pavia Triga Mark II research reactor for radiobiological and microdosimetric applications

    International Nuclear Information System (INIS)

    Nowadays the Pavia TRIGA reactor is available for national and international collaboration in various research fields. The TRIGA Mark II nuclear research reactor of the Pavia University offers different in- and out-core neutron irradiation channels, each characterised by different neutron spectra. In the last two years a campaign of measurements and simulations has been performed in order to guarantee a better characterisation of these different fluxes and to meet the demands of irradiations that require precise information on these spectra in particular for radiobiological and microdosimetric studies. Experimental data on neutron fluxes have been collected analysing and measuring the gamma activity induced in thin target foils of different materials irradiated in different TRIGA experimental channels. The data on the induced gamma activities have been processed with the SAND II deconvolution code and finally compared with the spectra obtained with Monte Carlo simulations. The comparison between simulated and measured spectra showed a good agreement allowing a more precise characterisation of the neutron spectra and a validation of the adopted method. (authors)

  10. Investigations of DNA damage induction and repair resulting from cellular exposure to high dose-rate pulsed proton beams

    Science.gov (United States)

    Renis, M.; Borghesi, M.; Favetta, M.; Malfa, G.; Manti, L.; Romano, F.; Schettino, G.; Tomasello, B.; Cirrone, G. A. P.

    2013-07-01

    Studies regarding the radiobiological effects of low dose radiation, microbeam irradiation services have been developed in the world and today laser acceleration of protons and heavy ions may be used in radiation therapy. The application of different facilities is essential for studying bystander effects and relating signalling phenomena in different cells or tissues. In particular the use of ion beams results advantageous in cancer radiotherapy compared to more commonly used X-rays, since the ability of ions in delivering lethal amount of doses into the target tumour avoiding or limiting damage to the contiguous healthy tissues. At the INFN-LNS in Catania, a multidisciplinary radiobiology group is strategically structured aimed to develop radiobiological research, finalised to therapeutic applications, compatible with the use of high dose laser-driven ion beams. The characteristic non-continuous dose rates with several orders of magnitude of laser-driven ion beams makes this facility very interesting in the cellular systems' response to ultra-high dose rates with non-conventional pulse time intervals cellular studies. Our group have projected to examine the effect of high dose laser-driven ion beams on two cellular types: foetal fibroblasts (normal control cells) and DU145 (prostate cancer cells), studying the modulation of some different bio-molecular parameters, in particular cell proliferation and viability, DNA damage, redox cellular status, morphological alterations of both the cytoskeleton components and some cell organelles and the possible presence of apoptotic or necrotic cell death. Our group performed preliminary experiments with high energy (60 MeV), dose rate of 10 Gy/min, doses of 1, 2, 3 Gy and LET 1 keV/μm on human foetal fibroblasts (control cells). We observed that cell viability was not influenced by the characteristics of the beam, the irradiation conditions or the analysis time. Conversely, DNA damage was present at time 0, immediately

  11. Radiobiological impact of dose calculation algorithms on biologically optimized IMRT lung stereotactic body radiation therapy plans

    International Nuclear Information System (INIS)

    The aim of this study is to evaluate the radiobiological impact of Acuros XB (AXB) vs. Anisotropic Analytic Algorithm (AAA) dose calculation algorithms in combined dose-volume and biological optimized IMRT plans of SBRT treatments for non-small-cell lung cancer (NSCLC) patients. Twenty eight patients with NSCLC previously treated SBRT were re-planned using Varian Eclipse (V11) with combined dose-volume and biological optimization IMRT sliding window technique. The total dose prescribed to the PTV was 60 Gy with 12 Gy per fraction. The plans were initially optimized using AAA algorithm, and then were recomputed using AXB using the same MUs and MLC files to compare with the dose distribution of the original plans and assess the radiobiological as well as dosimetric impact of the two different dose algorithms. The Poisson Linear-Quadatric (PLQ) and Lyman-Kutcher-Burman (LKB) models were used for estimating the tumor control probability (TCP) and normal tissue complication probability (NTCP), respectively. The influence of the model parameter uncertainties on the TCP differences and the NTCP differences between AAA and AXB plans were studied by applying different sets of published model parameters. Patients were grouped into peripheral and centrally-located tumors to evaluate the impact of tumor location. PTV dose was lower in the re-calculated AXB plans, as compared to AAA plans. The median differences of PTV(D95%) were 1.7 Gy (range: 0.3, 6.5 Gy) and 1.0 Gy (range: 0.6, 4.4 Gy) for peripheral tumors and centrally-located tumors, respectively. The median differences of PTV(mean) were 0.4 Gy (range: 0.0, 1.9 Gy) and 0.9 Gy (range: 0.0, 4.3 Gy) for peripheral tumors and centrally-located tumors, respectively. TCP was also found lower in AXB-recalculated plans compared with the AAA plans. The median (range) of the TCP differences for 30 month local control were 1.6 % (0.3 %, 5.8 %) for peripheral tumors and 1.3 % (0.5 %, 3.4 %) for centrally located tumors. The lower TCP

  12. Radiobiological investigations at tumor cell lines by exploiting aspects of chronological dose administration

    Directory of Open Access Journals (Sweden)

    Waldemar Ulmer

    2014-08-01

    Full Text Available Purpose: Using 31P-NMR spectroscopy the chronological behavior of the ATP-metabolism of the tumor spheroids C3H-MA, 9L-Gliome and the mono-layer L1210 has been analyzed via increase and decrease of the β-peak. The goal of this study is to elaborate an optimal fractionation scheme with regard to the irradiation of tumor spheroids and possibly to human tumors.  Methods: The NMR-spectroscopy has been carried out by the FID technique (free induction decay, and the intensity of the β-peak provides a measure of the survival fraction S after radiation exposure with 30 kV X-rays. The linear-quadratic model has to be generalized in order to be valid for irradiation beyond the shoulder. Results and Conclusion: All three cell lines show characteristic periods, and a homeostatic control cannot be recognized. Essential components of these periods are circadian (i.e. one day, circa-semiseptan (i.e. 3.5 days and circa-septan (i.e. one week. The determination of the survival fractions provides an optimum exploitation of radiation damages, when the ATP-concentration assumes a maximum value. This optimum is reached, when all three cycles exhibit an ATP maximum, which is only possible by accounting for the circa-septan rhythm.--------------------------------------Cite this article as: Ulmer W. Radiobiological investigations at tumor cell lines by exploiting aspects of chronological dose administration. Int J Cancer Ther Oncol 2014; 2(3:020312. DOI:10.14319/ijcto.0203.12 

  13. Functional and histological assessment of the radiobiology of normal rat lung in BNCT

    International Nuclear Information System (INIS)

    This study investigated the radiobiology and sensitivity of the normal rat lung to Boron Neutron Capture Therapy (BNCT) radiation. Rat thorax irradiations were carried out with x-rays or with neutrons in the presence or absence of p-boronophenylalanine (BPA). Lung damage were assessed functionally with breathing rate measurement up to 180 days after irradiation and then histologically. Breathing rates 20% (∼3 σ) above the control group (sham-irradiated rats) mean were considered as positive responses to lung radiation damage. Though most responding animals demonstrated radiation induced pneumonitis (≤110 days) as well as pulmonary fibrosis (>110 days), some animals receiving neutrons plus BPA showed only the latter. The breathing rate dose response data were fit using probit analysis. The ED50 values measured for x-rays, neutron beam only, and neutrons plus BPA were 11.5±0.4 Gy, 9.2±0.5 Gy, and 6.7±0.4 Gy, respectively. The biological weighting factors for the neutron beam (n+γ), the thermal neutron dose component, and the 10B dose component were determined to be 1.2±0.1, 2.2±0.4, and 2.3±0.3, respectively. The histological dose response curves were linear. Consistent with the functional assay, the weighting factors measured histologically were 1.2±0.1 for the thermal neutron beam and 1.9±0.2 for the 10B dose component. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Beyreuther, Elke

    2010-09-10

    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

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

    International Nuclear Information System (INIS)

    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. 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

    DEFF Research Database (Denmark)

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

    1998-01-01

    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....

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

    CERN Document Server

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

    2002-01-01

    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.

  18. Modelling cellular behaviour

    Science.gov (United States)

    Endy, Drew; Brent, Roger

    2001-01-01

    Representations of cellular processes that can be used to compute their future behaviour would be of general scientific and practical value. But past attempts to construct such representations have been disappointing. This is now changing. Increases in biological understanding combined with advances in computational methods and in computer power make it possible to foresee construction of useful and predictive simulations of cellular processes.

  19. Reversible quantum cellular automata

    CERN Document Server

    Schumacher, B

    2004-01-01

    We define quantum cellular automata as infinite quantum lattice systems with discrete time dynamics, such that the time step commutes with lattice translations and has strictly finite propagation speed. In contrast to earlier definitions this allows us to give an explicit characterization of all local rules generating such automata. The same local rules also generate the global time step for automata with periodic boundary conditions. Our main structure theorem asserts that any quantum cellular automaton is structurally reversible, i.e., that it can be obtained by applying two blockwise unitary operations in a generalized Margolus partitioning scheme. This implies that, in contrast to the classical case, the inverse of a nearest neighbor quantum cellular automaton is again a nearest neighbor automaton. We present several construction methods for quantum cellular automata, based on unitaries commuting with their translates, on the quantization of (arbitrary) reversible classical cellular automata, on quantum c...

  20. Action semantics modulate action prediction.

    Science.gov (United States)

    Springer, Anne; Prinz, Wolfgang

    2010-11-01

    Previous studies have demonstrated that action prediction involves an internal action simulation that runs time-locked to the real action. The present study replicates and extends these findings by indicating a real-time simulation process (Graf et al., 2007), which can be differentiated from a similarity-based evaluation of internal action representations. Moreover, results showed that action semantics modulate action prediction accuracy. The semantic effect was specified by the processing of action verbs and concrete nouns (Experiment 1) and, more specifically, by the dynamics described by action verbs (Experiment 2) and the speed described by the verbs (e.g., "to catch" vs. "to grasp" vs. "to stretch"; Experiment 3). These results propose a linkage between action simulation and action semantics as two yet unrelated domains, a view that coincides with a recent notion of a close link between motor processes and the understanding of action language.

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

    Science.gov (United States)

    Dorozhkina, Olga; Vorozhtsova, Svetlana; Ivanov, Alexander

    2016-07-01

    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

  2. Alpha Particle Emitter Radiolabeled Antibody for Metastatic Cancer: What Can We Learn from Heavy Ion Beam Radiobiology?

    Directory of Open Access Journals (Sweden)

    Hong Song

    2012-06-01

    Full Text Available Alpha-particle emitter labeled monoclonal antibodies are being actively developed for treatment of metastatic cancer due to the high linear energy transfer (LET and the resulting greater biological efficacy of alpha-emitters. Our knowledge of high LET particle radiobiology derives primarily from accelerated heavy ion beam studies. In heavy ion beam therapy of loco-regional tumors, the modulation of steep transition to very high LET peak as the particle approaches the end of its track (known as the Bragg peak enables greater delivery of biologically potent radiation to the deep seated tumors while sparing normal tissues surrounding the tumor with the relatively low LET track segment part of the heavy ion beam. Moreover, fractionation of the heavy ion beam can further enhance the peak-to-plateau relative biological effectiveness (RBE ratio. In contrast, internally delivered alpha particle radiopharmaceutical therapy lack the control of Bragg peak energy deposition and the dose rate is determined by the administered activity, alpha-emitter half-life and biological kinetics of the radiopharmaceutical. The therapeutic ratio of tumor to normal tissue is mainly achieved by tumor specific targeting of the carrier antibody. In this brief overview, we review the radiobiology of high LET radiations learned from ion beam studies and identify the features that are also applicable for the development of alpha-emitter labeled antibodies. The molecular mechanisms underlying DNA double strand break repair response to high LET radiation are also discussed.

  3. Heterogeneous cellular networks

    CERN Document Server

    Hu, Rose Qingyang

    2013-01-01

    A timely publication providing coverage of radio resource management, mobility management and standardization in heterogeneous cellular networks The topic of heterogeneous cellular networks has gained momentum in industry and the research community, attracting the attention of standardization bodies such as 3GPP LTE and IEEE 802.16j, whose objectives are looking into increasing the capacity and coverage of the cellular networks. This book focuses on recent progresses,  covering the related topics including scenarios of heterogeneous network deployment, interference management i

  4. DNA damage induction and/or repair as mammalian cell biomarker for the prediction of cellular radiation response

    Science.gov (United States)

    Baumstark-Khan, C.

    DNA damage and its repair processes are key factors in cancer induction and also in the treatment of malignancies. Cancer prevention during extended space missions becomes a topic of great importance for space radiobiology. The knowledge of individual responsiveness would allow the protection strategy to be tailored optimally in each case. Radiobiological analysis of cultured cells derived from tissue explants from individuals has shown that measurement of the surviving fraction after 2 Gy (SF2) may be used to predict the individual responsiveness. However, clonogenic assays are timeconsuming, thus alternative assays for the determination of radiore-sponse are being sought. For that reason CHO cell strains having different repair capacities were used for examining whether DNA strand break repair is a suitable experimental design to allow predictive statements. Cellular survival (CFA assay) and DNA strand breaks (total DNA strand breaks: FADU technique; DSBs: non-denaturing elution) were determined in parallel immediately after irradiation as well as after a 24 hour recovery period according to dose. There were no correlations between the dose-response curves of the initial level of DNA strand breaks and parameters that describe clonogenic survival curves (SF2). A good correlation exists between intrinsic cellular radioresistance and the extent of residual DNA strand breaks.

  5. Radiobiological evaluation of forward and inverse IMRT using different fractionations for head and neck tumours

    Directory of Open Access Journals (Sweden)

    Capela Miguel

    2010-06-01

    Full Text Available Abstract Purpose To quantify the radiobiological advantages obtained by an Improved Forward Planning technique (IFP and two IMRT techniques using different fractionation schemes for the irradiation of head and neck tumours. The conventional radiation therapy technique (CONVT was used here as a benchmark. Methods Seven patients with head and neck tumours were selected for this retrospective planning study. The PTV1 included the primary tumour, PTV2 the high risk lymph nodes and PTV3 the low risk lymph nodes. Except for the conventional technique where a maximum dose of 64.8 Gy was prescribed to the PTV1, 70.2 Gy, 59.4 Gy and 50.4 Gy were prescribed respectively to PTV1, PTV2 and PTV3. Except for IMRT2, all techniques were delivered by three sequential phases. The IFP technique used five to seven directions with a total of 15 to 21 beams. The IMRT techniques used five to nine directions and around 80 segments. The first, IMRT1, was prescribed with the conventional fractionation scheme of 1.8 Gy per fraction delivered in 39 fractions by three treatment phases. The second, IMRT2, simultaneously irradiated the PTV2 and PTV3 with 59.4 Gy and 50.4 Gy in 28 fractions, respectively, while the PTV1 was boosted with six subsequent fractions of 1.8 Gy. Tissue response was calculated using the relative seriality model and the Poisson Linear-Quadratic-Time model to simulate repopulation in the primary tumour. Results The average probability of total tumour control increased from 38% with CONVT to 80% with IFP, to 85% with IMRT1 and 89% with IMRT2. The shorter treatment time and larger dose per fraction obtained with IMRT2 resulted in an 11% increase in the probability of control in the PTV1 with respect to IFP and 7% relatively to IMRT1 (p Conclusions A significant improvement in treatment outcome was obtained with IMRT compared to conventional radiation therapy. The practical and biological advantages of IMRT2, employing a shorter treatment time, may

  6. Comparison of the radiobiological effects of Boron neutron capture therapy (BNCT) and conventional Gamma Radiation

    International Nuclear Information System (INIS)

    BNCT is an experimental radiotherapeutic modality that uses the capacity of the isotope 10B to capture thermal neutrons leading to the production of 4He and 7Li, particles with high linear energy transfer (LET). The aim was to evaluate and compare in vitro the mechanisms of response to the radiation arising of BNCT and conventional gamma therapy. We measured the survival cell fraction as a function of the total physical dose and analyzed the expression of p27/Kip1 and p53 by Western blotting in cells of colon cancer (ARO81-1). Exponentially growing cells were distributed into the following groups: 1) BPA (10 ppm 10B) + neutrons; 2) BOPP (10 ppm 10B) + neutrons; 3) neutrons alone; 4) gamma-rays. A control group without irradiation for each treatment was added. The cells were irradiated in the thermal neutron beam of the RA-3 (flux= 7.5 109 n/cm2 sec) or with 60Co (1Gy/min) during different times in order to obtain total physical dose between 1-5 Gy (±10 %). A decrease in the survival fraction as a function of the physical dose was observed for all the treatments. We also observed that neutrons and neutrons + BOPP did not differ significantly and that BPA was the more effective compound. Protein extracts of irradiated cells (3Gy) were isolated to 24 h and 48 h post radiation exposure. The irradiation with neutrons in presence of 10BPA or 10BOPP produced an increase of p53 at 24 h maintain until 48 h. On the contrary, in the groups irradiated with neutrons alone or gamma the peak was observed at 48 hr. The level of expression of p27/Kip1 showed a reduction of this protein in all the groups irradiated with neutrons (neutrons alone or neutrons plus boron compound), being more marked at 24 h. These preliminary results suggest different radiobiological response for high and low let radiation. Future studies will permit establish the role of cell cycle in the tumor radio sensibility to BNCT. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2012-10-15

    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

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

    International Nuclear Information System (INIS)

    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+), the overall probability of injury (pI), the overall probability of control/benefit (pB), and the biologically effective uniform dose (D¯¯). These radiobiologic measures were used to develop dose-response curves (p-D¯¯ 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+ index, the average values of the HT, IMRT, and CRT are 67.3%, 61.2%, and 68.2%, respectively. The corresponding average values of pB are 75.6%, 70.5%, and 71.0%, respectively, whereas the average values of pI 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 (DB¯¯) for the HT, IMRT, and CRT modalities are 64.0, 60.9, and 60.8 Gy

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

    Energy Technology Data Exchange (ETDEWEB)

    Komisopoulos, Georgios [Department of Medical Physics, Medical School, University of Patras, Patras (Greece); Mavroidis, Panayiotis, E-mail: mavroidis@uthscsa.edu [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)

    2014-01-01

    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

  10. Intentional Action and Action Slips.

    Science.gov (United States)

    Heckhausen, Heinz; Beckmann, Jurgen

    1990-01-01

    An explanation of action slips is offered that examines controlled actions in the context of an intentional behavior theory. Actions are considered guided by mentally represented intentions, subdivided into goal intentions and contingent instrumental intentions. Action slips are categorized according to problem areas in the enactment of goal…

  11. Nanostructured cellular networks.

    Science.gov (United States)

    Moriarty, P; Taylor, M D R; Brust, M

    2002-12-01

    Au nanocrystals spin-coated onto silicon from toluene form cellular networks. A quantitative statistical crystallography analysis shows that intercellular correlations drive the networks far from statistical equilibrium. Spin-coating from hexane does not produce cellular structure, yet a strong correlation is retained in the positions of nanocrystal aggregates. Mechanisms based on Marangoni convection alone cannot account for the variety of patterns observed, and we argue that spinodal decomposition plays an important role in foam formation.

  12. Cellular Cardiomyoplasty: Clinical Application

    OpenAIRE

    Chachques, J. (J.); Acar, C; J. Herreros; Trainini, J. (Jorge); Prosper, F.; D’Attellis, N. (N.); Fabiani, J. N.; Carpentier, A

    2004-01-01

    Myocardial regeneration can be induced with the implantation of a variety of myogenic and angiogenic cell types. More than 150 patients have been treated with cellular cardiomyoplasty worldwide, 18 patients have been treated by our group. Cellular cardiomyoplasty seems to reduce the size and fibrosis of infarct scars, limit postischemic remodelling, and restore regional myocardial contractility. Techniques for skeletal myoblasts culture and ex vivo expansion using auto...

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2014-10-15

    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

  14. 2. International conference. Radiobiological consequences of nuclear accidents; Russian-Norwegian Satellite Symposium on nuclear accidents, radioecology and health. Abstracts. Part 2

    International Nuclear Information System (INIS)

    Materials on radiobiological effect of ionizing radiation under emergency situations are presented. The radiation contamination of environmental media after the Chernobyl NPP accident (ground, earth and water ecological systems), effect of external and internal irradiation on the inhabitants of the region are estimated. Time characteristic of radiation risk of originating tumors and genetic injuries is given

  15. PI3K signalling in GnRH actions on dispersed goldfish pituitary cells: relationship with PKC-mediated LH and GH release and regulation of long-term effects on secretion and total cellular hormone availability.

    Science.gov (United States)

    Pemberton, Joshua G; Orr, Michael E; Stafford, James L; Chang, John P

    2014-09-01

    Goldfish pituitary cells are exposed to two GnRHs, salmon (s)GnRH and chicken (c)GnRH-II. Phosphoinositide 3-kinase (PI3K) and protein kinase C (PKC) both participate in acute sGnRH- and cGnRH-II-stimulated LH and GH release. Using goldfish pituitary cells, we examined the relationship between PI3K and PKC in acute LH and GH secretion, and PI3K involvement in chronic hormone release and total LH and GH availability. The PI3K inhibitor LY294002 did not affect PKC agonists-induced LH or GH release, and PKC agonists did not alter PI3K p85 phosphorylation, suggesting PKC activation is not upstream of PI3K in acute hormone release. In 2, 6, 12 and 24h treatments, LY294002 did not affect LH release but stimulated total LH availability at 6h. sGnRH stimulatory actions on LH release and total availability at 12 and 24h, and cGnRH-II effects on these parameters at 6h were inhibited by LY294002. LY294002 enhanced basal GH release at 2 and 6h, but reduced total GH at 12 and 24h. Increased GH release was seen following 6, 12 and 24h of sGnRH, and 2, 6 and 24h of cGnRH-II treatment but total GH availability was only elevated by 24h cGnRH-II treatment. Whereas LY294002 inhibited GH release responses to sGnRH at 12h and cGnRH-II at 6h, it attenuated cGnRH-II-elicited, but not sGnRH-induced, effects on total GH. These results indicate that PI3K differentially modulates long-term basal and GnRH-stimulated hormone release, and total hormone availability, in a time-, cell-type-, and GnRH isoform-selective manner. PMID:24681225

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

    Energy Technology Data Exchange (ETDEWEB)

    Baumann, M.; Dahm-Daphi, J.; Dikomey, E.; Petersen, C.; Rodemann, H.P.; Zips, D. (eds.)

    2007-07-01

    The following topics were dealt with: DNA repair as therapeutical target in radiation therapy, biological imaging and tumor microenvironment, molecular factors of radiation therapy, molecular factors and modulation of the radiation reaction of normal tissues, experimental tumor therapy, EGFR inhibition, the endothel cell as primary target of radiation therapy, molecular and cellular foundations of the radiation biology of protons and ions. (HSI)

  17. Maintenance of radiation-induced intestinal fibrosis: Cellular and molecular features

    Institute of Scientific and Technical Information of China (English)

    Valérie Haydont; Marie-Catherine Vozenin-Brotons

    2007-01-01

    Recent advances in cell and molecular radiobiology clearly showed that tissue response to radiation injury cannot be restricted to a simple cell-killing process, but depends upon continuous and integrated pathogenic processes, involving cell differentiation and crosstalk between the various cellular components of the tissue within the extracellular matrix. Thus, the prior concept of primary cell target in which a single-cell type (whatever it's epithelial or endothelial cells) dictates the whole tissue response to radiation injury has to be replaced by the occurrence of coordinated multicellular response that may either lead to tissue recovery or to sequel development. In this context, the present review will focus on the maintenance of the radiation-induced wound healing and fibrogenic signals triggered by and through the microenvironment toward the mesencnymal cell compartment, and will highlight how sequential and sustained modifications in cell phenotypes will in cascade modify cell-to-cell interactions and tissue composition.

  18. Action physics

    Science.gov (United States)

    McGinness, Lachlan P.; Savage, C. M.

    2016-09-01

    More than a decade ago, Edwin Taylor issued a "call to action" that presented the case for basing introductory university mechanics teaching around the principle of stationary action [E. F. Taylor, Am. J. Phys. 71, 423-425 (2003)]. We report on our response to that call in the form of an investigation of the teaching and learning of the stationary action formulation of physics in a first-year university course. Our action physics instruction proceeded from the many-paths approach to quantum physics to ray optics, classical mechanics, and relativity. Despite the challenges presented by action physics, students reported it to be accessible, interesting, motivational, and valuable.

  19. Radiobiology in clinical radiation therapy part II: current practice and new horizons

    International Nuclear Information System (INIS)

    Objective: This course is designed for residents in radiation oncology, preparing for their boards. It includes the physics and chemistry of the absorption of radiation, a description of the biological systems used to obtain a quantitative relationship between dose and biological effect, as well as a review of the basic principles in radiation biology that have been established. The multifraction regimens used in conventional radiotherapy were developed empirically, but can be understood in terms of radiobiological principles. Dividing the dose into many fractions reduces biological effectiveness due to repair of sublethal damage; this occurs in both tumors and normal tissues. Fractionation allows re-oxygenation to occur in tumors and so increases the effectiveness of a given total dose. Fractionation also leads to sensitization by reassortment of cycling tumor cells into radiosensitive phases of the cycle. Laboratory research also provides a rationale for modifications of existing fractionation protocols. The dose response relationship for late responding tissues is more 'curved' than for acute or early effects. Consequently the use of multiple fractions allows a greater separation of early and late effects in normal tissues. This has led to the introduction of hyperfractionation and accelerated treatment. Both involve two treatments per day (BID) but based on quite different rationales. The limitation of protraction is cell proliferation in the tumor, which may be accelerated as the tumor shrinks. Measurements of cell kinetics can identify fast growing tumors that may benefit from accelerated treatment. Hypoxia was early identified as a cause of resistance to cell killing x-rays. This led to development of electron affinic compounds as radiosensitizers of hypoxic cells. The new trend is the development of bioreductive drugs that are specifically cytotoxic to hypoxic cells i.e. hypoxic cytotoxins, but which still need to be combined with radiation. Fast neutrons

  20. Radiobiological evaluation of forward and inverse IMRT using different fractionations for head and neck tumours

    International Nuclear Information System (INIS)

    To quantify the radiobiological advantages obtained by an Improved Forward Planning technique (IFP) and two IMRT techniques using different fractionation schemes for the irradiation of head and neck tumours. The conventional radiation therapy technique (CONVT) was used here as a benchmark. Seven patients with head and neck tumours were selected for this retrospective planning study. The PTV1 included the primary tumour, PTV2 the high risk lymph nodes and PTV3 the low risk lymph nodes. Except for the conventional technique where a maximum dose of 64.8 Gy was prescribed to the PTV1, 70.2 Gy, 59.4 Gy and 50.4 Gy were prescribed respectively to PTV1, PTV2 and PTV3. Except for IMRT2, all techniques were delivered by three sequential phases. The IFP technique used five to seven directions with a total of 15 to 21 beams. The IMRT techniques used five to nine directions and around 80 segments. The first, IMRT1, was prescribed with the conventional fractionation scheme of 1.8 Gy per fraction delivered in 39 fractions by three treatment phases. The second, IMRT2, simultaneously irradiated the PTV2 and PTV3 with 59.4 Gy and 50.4 Gy in 28 fractions, respectively, while the PTV1 was boosted with six subsequent fractions of 1.8 Gy. Tissue response was calculated using the relative seriality model and the Poisson Linear-Quadratic-Time model to simulate repopulation in the primary tumour. The average probability of total tumour control increased from 38% with CONVT to 80% with IFP, to 85% with IMRT1 and 89% with IMRT2. The shorter treatment time and larger dose per fraction obtained with IMRT2 resulted in an 11% increase in the probability of control in the PTV1 with respect to IFP and 7% relatively to IMRT1 (p < 0.05). The average probability of total patient complications was reduced from 80% with CONVT to 61% with IFP and 31% with IMRT. The corresponding probability of complications in the ipsilateral parotid was 63%, 42% and 20%; in the contralateral parotid it was 50%, 20

  1. Complementary Actions

    Directory of Open Access Journals (Sweden)

    Luisa eSartori

    2015-05-01

    Full Text Available Complementary colors are color pairs which, when combined in the right proportions, produce white or black. Complementary actions refer here to forms of social interaction wherein individuals adapt their joint actions according to a common aim. Notably, complementary actions are incongruent actions. But being incongruent is not sufficient to be complementary (i.e., to complete the action of another person. Successful complementary interactions are founded on the abilities: (i to simulate another person’s movements, (ii to predict another person’s future action/s, (iii to produce an appropriate incongruent response which differ, while interacting, with observed ones, and (iv to complete the social interaction by integrating the predicted effects of one’s own action with those of another person. This definition clearly alludes to the functional importance of complementary actions in the perception–action cycle and prompts us to scrutinize what is taking place behind the scenes. Preliminary data on this topic have been provided by recent cutting-edge studies utilizing different research methods. This mini-review aims to provide an up-to-date overview of the processes and the specific activations underlying complementary actions.

  2. Epigenetics and Cellular Metabolism

    Science.gov (United States)

    Xu, Wenyi; Wang, Fengzhong; Yu, Zhongsheng; Xin, Fengjiao

    2016-01-01

    Living eukaryotic systems evolve delicate cellular mechanisms for responding to various environmental signals. Among them, epigenetic machinery (DNA methylation, histone modifications, microRNAs, etc.) is the hub in transducing external stimuli into transcriptional response. Emerging evidence reveals the concept that epigenetic signatures are essential for the proper maintenance of cellular metabolism. On the other hand, the metabolite, a main environmental input, can also influence the processing of epigenetic memory. Here, we summarize the recent research progress in the epigenetic regulation of cellular metabolism and discuss how the dysfunction of epigenetic machineries influences the development of metabolic disorders such as diabetes and obesity; then, we focus on discussing the notion that manipulating metabolites, the fuel of cell metabolism, can function as a strategy for interfering epigenetic machinery and its related disease progression as well. PMID:27695375

  3. Architected Cellular Materials

    Science.gov (United States)

    Schaedler, Tobias A.; Carter, William B.

    2016-07-01

    Additive manufacturing enables fabrication of materials with intricate cellular architecture, whereby progress in 3D printing techniques is increasing the possible configurations of voids and solids ad infinitum. Examples are microlattices with graded porosity and truss structures optimized for specific loading conditions. The cellular architecture determines the mechanical properties and density of these materials and can influence a wide range of other properties, e.g., acoustic, thermal, and biological properties. By combining optimized cellular architectures with high-performance metals and ceramics, several lightweight materials that exhibit strength and stiffness previously unachievable at low densities were recently demonstrated. This review introduces the field of architected materials; summarizes the most common fabrication methods, with an emphasis on additive manufacturing; and discusses recent progress in the development of architected materials. The review also discusses important applications, including lightweight structures, energy absorption, metamaterials, thermal management, and bioscaffolds.

  4. Epigenetics and Cellular Metabolism

    Science.gov (United States)

    Xu, Wenyi; Wang, Fengzhong; Yu, Zhongsheng; Xin, Fengjiao

    2016-01-01

    Living eukaryotic systems evolve delicate cellular mechanisms for responding to various environmental signals. Among them, epigenetic machinery (DNA methylation, histone modifications, microRNAs, etc.) is the hub in transducing external stimuli into transcriptional response. Emerging evidence reveals the concept that epigenetic signatures are essential for the proper maintenance of cellular metabolism. On the other hand, the metabolite, a main environmental input, can also influence the processing of epigenetic memory. Here, we summarize the recent research progress in the epigenetic regulation of cellular metabolism and discuss how the dysfunction of epigenetic machineries influences the development of metabolic disorders such as diabetes and obesity; then, we focus on discussing the notion that manipulating metabolites, the fuel of cell metabolism, can function as a strategy for interfering epigenetic machinery and its related disease progression as well.

  5. DOE life-span radiation effects studies in experimental animals at University of Utah Division of Radiobiology

    International Nuclear Information System (INIS)

    The Radiobiology Laboratory at the University of Utah compared the long-term biological effects of 226Ra and 239Pu in adult beagles. The program includes the investigation of other radionuclides. More recently, groups of juvenile and aged beagles were added to the study to investigate the influence of age at exposure. These studies involved single intravenous injection of radionuclides to small groups of beagles, in graded doses from levels at which no effects were expected up to levels where a 100% incidence of bone tumors was sometimes found. Some of the principal effects were bone tumors, fractures, and other skeletal alterations observed radiographically and histologically; emphasis was placed on the detection of precancerous changes, hematological changes, and changes related to aging. Emphasis was also placed on metabolic and autoradiographic studies necessary for good radiation dosimetry

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2015-09-15

    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

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

    Science.gov (United States)

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

    2004-01-01

    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.

  8. Radiobiological parameters of four glioblastoma compared to four other histological types of human tumor xenografts in nude mice

    International Nuclear Information System (INIS)

    Purpose/Objective: Glioblastoma Multiforme (GBM) is a highly malignant tumor of the central nervous system with aggressive biological behavior and a fatal clinical outcome. Several radiobiological parameters might contribute to these poor results. In this study, we investigated seventeen biological parameters of four GBM xenografts and compared the results with four other histological types of human tumor xenografts in nude mice. Methods and Materials: Most of the xenografts retained the individual histological features of their original tumor types. Four GBM xenografts (U87, HP555, MMC1 and HGL21), two squamous cell carcinomas (SCC21 and FaDu), one soft tissue sarcoma (STS26T), and colon cancer (HCT15) xenografts were used. The tumors were implanted in the hindleg of 5-6 Gy WBI nude mice. The following parameters were investigated for most of the xenografts: fractionated TCD50 (the dose of radiation which controls 50% of the tumors) using 30 fractions in 15 days. The parameters pO2, IFP (interstitial fluid pressure), Tpot, SF2 (plastic and Courtenay), PE (plating efficiency), D0, GSH, TCD50 single dose in oxic and hypoxic conditions, the rate of metastasis in SCID mice, VDT (volume doubling time), spontaneous apoptosis, induced apoptosis after 30 and 60 Gy and p53 over-expression. Results: Using the t-test, there was a significantly less spontaneous apoptosis in GBM xenografts when compared with the other histological types. However, no significant difference was found between both groups of xenografts in the remaining biological parameters investigated. Conclusion: These data demonstrate that, with the exception of spontaneous apoptosis, no significant difference was found in fifteen biological parameters between GBM xenografts and the other histological types implanted into the subcutaneous tissue of nude mice. The data suggests that the classical radiobiological parameters cannot explain the poor response of GBM to radiation. Supported by NCI Grant CA13311

  9. Mode of Action of Mycotoxins

    Science.gov (United States)

    Mycotoxins are a structurally disparate group of toxic chemicals. There only common link is that they are all produced by fungi. It is therefore not surprising that their biochemical mechanisms of action are as diverse as their taxonomic origins. The study of biochemical and cellular mechanisms o...

  10. Cellular Response to Irradiation

    Institute of Scientific and Technical Information of China (English)

    LIU Bo; YAN Shi-Wei

    2011-01-01

    To explore the nonlinear activities of the cellular signaling system composed of one transcriptional arm and one protein-interaction arm, we use an irradiation-response module to study the dynamics of stochastic interactions.It is shown that the oscillatory behavior could be described in a unified way when the radiation-derived signal and noise are incorporated.

  11. The New Cellular Immunology

    Science.gov (United States)

    Claman, Henry N.

    1973-01-01

    Discusses the nature of the immune response and traces many of the discoveries that have led to the present state of knowledge in immunology. The new cellular immunology is directing its efforts toward improving health by proper manipulation of the immune mechanisms of the body. (JR)

  12. Molecular and cellular level of action of digitalis.

    Science.gov (United States)

    Charlemagne, D

    1993-04-01

    The pharmacological receptor of cardiac glycosides is the Na+/K(+)-ATPase which consists of a catalytic alpha (M(r) = 112,000) and glycosylated beta (M(r) = 35,000) subunit. The enzyme is responsible for the vectorial transport across the sarcolemma of three Na+ ions outward and two K+ ions inward against their electrochemical gradient. Specific inhibition of the Na+ pump by digitalis induces a positive inotropic effect by increasing the intracellular Na+ concentration which in turn induces an increase in the intracellular Ca2+ concentration by the Na+/Ca2+ exchange and an increase in the Ca2+ pool of the sarcoplasmic reticulum; toxic effects are observed at higher doses of cardiac glycosides leading to spontaneous calcium release from the sarcoplasmic reticulum. Three isoforms of the alpha catalytic subunit have been identified by molecular cloning. They share a high homology in the deduced amino acid sequence with eight transmembrane domains. The ouabain binding domain is located on the extracellular side and ouabain sensitivity depends mainly on the two residues at the border of the first extracellular domain. The isoforms differed by their ouabain sensitivity, are expressed in a tissue-specific and hormonally-regulated manner. Moreover, expression of the isoforms and their ouabain sensitivity vary from species to species with an alpha 1 isoform of very low affinity being the major isoform (80%) in the adult rat heart and an alpha 1 isoform of high affinity representing 50% of total alpha mRNA abundance in the human heart. Therefore the effect of digitalis on the heart depends mainly on the isoform which is expressed and on the regulation of their expression according to age, hormonal influence and pathology. PMID:7684015

  13. Enforcement actions: Significant actions resolved

    International Nuclear Information System (INIS)

    This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (October - December 1993) and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to licensees with respect to these enforcement actions. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication

  14. Enforcement actions: Significant actions resolved

    International Nuclear Information System (INIS)

    This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (July - September 1992) and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to licensees with respect to these enforcement actions. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication

  15. Elucidation of the new generation fluorescent protein tdTomato for space related radiobiological research

    Science.gov (United States)

    Chishti, Arif Ali; Baumstark-Khan, Christa; Hellweg, Christine; Reitz, Guenther

    Astronauts in space are exposed to a potentially harmful radiation field, which does not exist in its quality and quantity on earth. Radiation exposure in space can lead to delayed or acute health effects. A successful long-term space mission requires better risk estimation and development of appropriate countermeasures, therefore study of the cellular radiation response is necessary. Ionizing radiation can provoke active cellular responses (cell cycle arrest, DNA repair, apoptosis or other forms of cell type). Exposure to ionizing radiation also activates various signaling pathways in human cells. In the cellular radiation-response, two pivotal signal transduction pathways have to be comprehensively studied i.e. the p53-pathway and NF-κB-pathway. Discovery of fluorescent proteins has revolutionized biological research by making it possible to carry out functional studies in living cells and understanding complex signaling pathways. Previously the green fluorescent proteins EGFP and d2EGFP were used for signaling pathway studies. In this work the new red fluorescent protein tdTomato will be used for comprehensive investigation of NF-κB and other transcription factor activation after exposure of human cells to ionizing radiation (X-rays, heavy ions; space conditions). tdTomato has many advantages over EGFP because of its high fluorescence signals and a better signal/noise ratio in human cells. The previously constructed reporter system with d2EGFP was used to evaluate NF-kB activation after exposure to heavy ion particles of different biological effectiveness. The sensitivity threshold of this system was determined to be 2 particle traversals per cell nucleus. In the current study a more sensitive reporter assay will be constructed using a GAL4-VP16 turbo system that comprises a receptor plasmid and a reporter plasmid. This reporter assay will be designed and constructed with tdTomato and evaluation will be done with different molecular techniques.

  16. Enforcement actions: Significant actions resolved

    International Nuclear Information System (INIS)

    This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (January--March 1989) and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to licensees with respect to these enforcement actions. Also included are a number of enforcement actions that had been previously resolved but not published in this NUREG. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication

  17. Enforcement actions: Significant actions resolved

    International Nuclear Information System (INIS)

    This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (January--March 1990) and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to licensees with respect to these enforcement actions. Also included are a number of enforcement actions that had been previously resolved but not published in this NUREG. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication

  18. Molecular and Cellular Signaling

    CERN Document Server

    Beckerman, Martin

    2005-01-01

    A small number of signaling pathways, no more than a dozen or so, form a control layer that is responsible for all signaling in and between cells of the human body. The signaling proteins belonging to the control layer determine what kinds of cells are made during development and how they function during adult life. Malfunctions in the proteins belonging to the control layer are responsible for a host of human diseases ranging from neurological disorders to cancers. Most drugs target components in the control layer, and difficulties in drug design are intimately related to the architecture of the control layer. Molecular and Cellular Signaling provides an introduction to molecular and cellular signaling in biological systems with an emphasis on the underlying physical principles. The text is aimed at upper-level undergraduates, graduate students and individuals in medicine and pharmacology interested in broadening their understanding of how cells regulate and coordinate their core activities and how diseases ...

  19. Magnetic Cellular Switches

    OpenAIRE

    Overby, Darryl R.; Alenghat, Francis J.; Montoya-Zavala, Martín; Bei, HuCheng; Oh, Philmo; Karavitis, John; Ingber, Donald E.

    2004-01-01

    This paper focuses on the development of magnetic cellular switches to enable magnetic control of intracellular functions in living mammalian cells, including receptor signal transduction and gene transcription. Our approach takes advantage of the mechanosensitivity of adenosine 3′,5′-monophosphate (cAMP) induction and downstream transcription controlled by the cAMP regulatory element (CRE) to engineer gene constructs that optically report gene expression in living cells. We activate transcri...

  20. Cellular therapy in Tuberculosis

    Directory of Open Access Journals (Sweden)

    Shreemanta K. Parida

    2015-03-01

    Full Text Available Cellular therapy now offer promise of potential adjunct therapeutic options for treatment of drug-resistant tuberculosis (TB. We review here the role of Mesenchymal stromal cells, (MSCs, as well as other immune effector cells in the therapy of infectious diseases with a focus on TB. MSCs represent a population of tissue-resident non-hematopoietic adult progenitor cells which home into injured tissues increase the proliferative potential of broncho-alveolar stem cells and restore lung epithelium. MSCs have been shown to be immune-modulatory and anti-inflammatory mediated via cell-cell contacts as well as soluble factors. We discuss the functional profile of MSCs and their potential use for adjunct cellular therapy of multi-drug resistant TB, with the aim of limiting tissue damage, and to convert unproductive inflammatory responses into effective anti-pathogen directed immune responses. Adjunct cellular therapy could potentially offer salvage therapy options for patients with drug-resistant TB, increase clinically relevant anti-M.tuberculosis directed immune responses and possibly shorten the duration of anti-TB therapy.

  1. The brittleness model of complex system based on cellular automata

    Institute of Scientific and Technical Information of China (English)

    LIN De-ming; JIN Hong-zhang; LI Qi; WU Hong-mei

    2004-01-01

    Now the research on the complex system is a hot spot. Brittleness is one of the basic characteristics of a complex system. In a complex system, after one of subsystems is struck to be collapsed, the whole system will collapse. Meanwhile, cellular automata is a discrete dynamic system. When the rule is given, the cellular automata could be defined. Then it can imitate the complex action. Cellular automata is used to simulate the brittleness action in this study. Entropy was used to analyze the action and get the rule. Then,three normal brittleness models were given. The result shows that the brittleness of complex system is existent and in addition some important behavior mode of complex system brittleness has been achieved.

  2. Environment Aware Cellular Networks

    KAUST Repository

    Ghazzai, Hakim

    2015-02-01

    The unprecedented rise of mobile user demand over the years have led to an enormous growth of the energy consumption of wireless networks as well as the greenhouse gas emissions which are estimated currently to be around 70 million tons per year. This significant growth of energy consumption impels network companies to pay huge bills which represent around half of their operating expenditures. Therefore, many service providers, including mobile operators, are looking for new and modern green solutions to help reduce their expenses as well as the level of their CO2 emissions. Base stations are the most power greedy element in cellular networks: they drain around 80% of the total network energy consumption even during low traffic periods. Thus, there is a growing need to develop more energy-efficient techniques to enhance the green performance of future 4G/5G cellular networks. Due to the problem of traffic load fluctuations in cellular networks during different periods of the day and between different areas (shopping or business districts and residential areas), the base station sleeping strategy has been one of the main popular research topics in green communications. In this presentation, we present several practical green techniques that provide significant gains for mobile operators. Indeed, combined with the base station sleeping strategy, these techniques achieve not only a minimization of the fossil fuel consumption but also an enhancement of mobile operator profits. We start with an optimized cell planning method that considers varying spatial and temporal user densities. We then use the optimal transport theory in order to define the cell boundaries such that the network total transmit power is reduced. Afterwards, we exploit the features of the modern electrical grid, the smart grid, as a new tool of power management for cellular networks and we optimize the energy procurement from multiple energy retailers characterized by different prices and pollutant

  3. Mitochondria and ionizing radiation: their inter relationship toward cellular dysfunction

    International Nuclear Information System (INIS)

    The contemporary theory of radiobiology posit that cellular damage during an event of radiation exposure is mediated through DNA damage/repair signaling processes along with secondary mechanisms induced by free radical generation. Nevertheless, up-coming experimental data suggests that this speculative framework is not enough for unfolding extranuclear radiation effects, particularly the response of mitochondria, key organelles for maintaining cellular function. Therefore, the present study aims at understanding ionizing radiation induced cellular damage and the associated mitochondrial structure/functional changes, using normal human fibroblast cells as an experimental model. Cells were exposed to X-rays (using Faxitron CP 160; dose rate 1 Gray (Gy)/min, fitted with 0.5 mm Al filter). Changes in the mitochondrial structure/mass were investigated by fluorescence microscopy and fluorimetry using MiTotracker red/nonyl-acridine orange dyes. Functional changes were measured by comparative measurement of cytosolic/mitochondrial ROS release using DCFH2DA/MiToSOX dye, mitochondrial membrane potential (MMP) using Rhodamine 123, activity of respiratory complexes, ATP synthesis and DNA damage using long amplicon (LA) PCR. Results obtained showed that exposure to X-rays led to mitochondrial fragmentation, concomitantly increasing the mitochondrial mass. Elevated cytosolic ROS levels were correlated with increased mitochondrial superoxide levels in case of X-ray treated cells indicating increased oxidative stress accompanied by depletion in MMP and activity of respiratory enzyme complexes followed by lowering of ATP levels. LA-PCR data showed time dependent decrease in the amplification of 8.9 kb region of mitochondrial DNA and 13.5 kb region of beta-globin nuclear gene segment indicating ROS precedes mtDNA damage exhibiting the deleterious nature of X-ray which may be considered as a key causative factor for mitochondrial dysfunction. Also, the role of DRP1 (dynamin

  4. Research in theoretical radiobiology and radiological physics: Final technical report, May 1, 1986-December 31, 1987

    International Nuclear Information System (INIS)

    The work carried out under this Grant included continuation of experimental research in radiation biophysics that was previously initiated, as well as extensive theoretical efforts primarily devoted to the further development of the Theory of Dual Radiation Action. Documents for international and national organizations were prepared or evaluated. Attendance at a number of international and national meetings and scientific correspondence were also in part supported by this grant. 14 refs

  5. SU-E-T-399: Determination of the Radiobiological Parameters That Describe the Dose-Response Relations of Xerostomia and Disgeusia From Head and Neck Radiotherapy

    International Nuclear Information System (INIS)

    Purpose: To estimate the radiobiological parameters that describe the doseresponse relations of xerostomia and disgeusia from head and neck cancer radiotherapy. To identify the organs that are best correlated with the manifestation of those clinical endpoints. Finally, to evaluate the goodnessof- fit by comparing the model predictions against the actual clinical results. Methods: In this study, 349 head and neck cancer patients were included. For each patient the dose volume histograms (DVH) of parotids (separate and combined), mandible, submandibular glands (separate and combined) and salivary glands were calculated. The follow-up of those patients was recorded at different times after the completion of the treatment (7 weeks, 3, 7, 12, 18 and 24 months). Acute and late xerostomia and acute disgeusia were the clinical endpoints examined. A maximum likelihood fitting was performed to calculate the best estimates of the parameters used by the relative seriality model. The statistical methods of the error distribution, the receiver operating characteristic (ROC) curve, the Pearson's test and the Akaike's information criterion were utilized to assess the goodness-of-fit and the agreement between the pattern of the radiobiological predictions with that of the clinical records. Results: The estimated values of the radiobiological parameters of salivary glands are D50 = 25.2 Gy, γ = 0.52, s = 0.001. The statistical analysis confirmed the clinical validity of those parameters (area under the ROC curve = 0.65 and AIC = 38.3). Conclusion: The analysis proved that the treatment outcome pattern of the patient material can be reproduced by the relative seriality model and the estimated radiobiological parameters. Salivary glands were found to have strong volume dependence (low relative seriality). Diminishing the biologically effective uniform dose to salivary glands below 30 Gy may significantly reduce the risk of complications to the patients irradiated for

  6. SU-E-T-399: Determination of the Radiobiological Parameters That Describe the Dose-Response Relations of Xerostomia and Disgeusia From Head and Neck Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Mavroidis, P; Stathakis, S; Papanikolaou, N [University of Texas Health Science Center, UTHSCSA, San Antonio, TX (United States); Peixoto Xavier, C [University of Coimbra, Coimbra, Coimbra (Portugal); Costa Ferreira, B [University of Aveiro, Coimbra, Coimbra (Portugal); Khouri, L; Carmo Lopes, M do [IPOCFG, EPE, Coimbra, Coimbra (Portugal)

    2014-06-01

    Purpose: To estimate the radiobiological parameters that describe the doseresponse relations of xerostomia and disgeusia from head and neck cancer radiotherapy. To identify the organs that are best correlated with the manifestation of those clinical endpoints. Finally, to evaluate the goodnessof- fit by comparing the model predictions against the actual clinical results. Methods: In this study, 349 head and neck cancer patients were included. For each patient the dose volume histograms (DVH) of parotids (separate and combined), mandible, submandibular glands (separate and combined) and salivary glands were calculated. The follow-up of those patients was recorded at different times after the completion of the treatment (7 weeks, 3, 7, 12, 18 and 24 months). Acute and late xerostomia and acute disgeusia were the clinical endpoints examined. A maximum likelihood fitting was performed to calculate the best estimates of the parameters used by the relative seriality model. The statistical methods of the error distribution, the receiver operating characteristic (ROC) curve, the Pearson's test and the Akaike's information criterion were utilized to assess the goodness-of-fit and the agreement between the pattern of the radiobiological predictions with that of the clinical records. Results: The estimated values of the radiobiological parameters of salivary glands are D50 = 25.2 Gy, γ = 0.52, s = 0.001. The statistical analysis confirmed the clinical validity of those parameters (area under the ROC curve = 0.65 and AIC = 38.3). Conclusion: The analysis proved that the treatment outcome pattern of the patient material can be reproduced by the relative seriality model and the estimated radiobiological parameters. Salivary glands were found to have strong volume dependence (low relative seriality). Diminishing the biologically effective uniform dose to salivary glands below 30 Gy may significantly reduce the risk of complications to the patients irradiated for

  7. Safety-Evaluation Report related to the renewal of the operating license for the research reactor at the Armed Forces Radiobiology Research Institute. Docket No. 50-170

    International Nuclear Information System (INIS)

    Supplement 1 to the Safety Evaluation Report related to the renewal of the operating license for the research reactor at the Armed Forces Radiobiology Research Institute has been prepared by the Office of Nuclear Reactor Regulation of the US Nuclear Regulatory Commission. The reactor facility is located in Montgomery County, Maryland. This supplement reports on the status of the licensee's emergency plan that had not been reviewed at the time the Safety Evaluation Report (NUREG-0882) was published

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

    International Nuclear Information System (INIS)

    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 99mTc-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 99mTc-MAA SPECT images. The reconstruction protocol was optimized. Concordance of 99mTc-MAA and 90Y 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 90Y 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 (BEDave) 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 derived. The area under the curve (AUC

  9. Use of the NASA Space Radiation Laboratory at Brookhaven National Laboratory to Conduct Charged Particle Radiobiology Studies Relevant to Ion Therapy.

    Science.gov (United States)

    Held, Kathryn D; Blakely, Eleanor A; Story, Michael D; Lowenstein, Derek I

    2016-06-01

    Although clinical studies with carbon ions have been conducted successfully in Japan and Europe, the limited radiobiological information about charged particles that are heavier than protons remains a significant impediment to exploiting the full potential of particle therapy. There is growing interest in the U.S. to build a cancer treatment facility that utilizes charged particles heavier than protons. Therefore, it is essential that additional radiobiological knowledge be obtained using state-of-the-art technologies and biological models and end points relevant to clinical outcome. Currently, most such ion radiotherapy-related research is being conducted outside the U.S. This article addresses the substantial contributions to that research that are possible at the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL), which is the only facility in the U.S. at this time where heavy-ion radiobiology research with the ion species and energies of interest for therapy can be done. Here, we briefly discuss the relevant facilities at NSRL and how selected charged particle biology research gaps could be addressed using those facilities. PMID:27195609

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

    Energy Technology Data Exchange (ETDEWEB)

    Pedicini, Piernicola, E-mail: ppiern@libero.it [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)

    2013-04-01

    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.

  11. Engineering Cellular Metabolism

    DEFF Research Database (Denmark)

    Nielsen, Jens; Keasling, Jay

    2016-01-01

    of metabolic engineering and will discuss how new technologies can enable metabolic engineering to be scaled up to the industrial level, either by cutting off the lines of control for endogenous metabolism or by infiltrating the system with disruptive, heterologous pathways that overcome cellular regulation.......Metabolic engineering is the science of rewiring the metabolism of cells to enhance production of native metabolites or to endow cells with the ability to produce new products. The potential applications of such efforts are wide ranging, including the generation of fuels, chemicals, foods, feeds...

  12. Radiobiology of the skin: review of some effects on epidermis and hair

    International Nuclear Information System (INIS)

    Significant doses of ionizing radiation produce an acute skin reaction characterized by erythema, epilation, and dry or moist desquamation with or without erosions. These early acute changes are dose-dependent and reflect damage to the germinative cells of the epidermis and to the cutaneous vasculature. Studies in the pig, for example, have shown that the degenerative phase of cell loss (2-3 weeks) results from reproductive failure in germinative cells and a sharp reduction in the proliferation rate of basal cell ''survivors.'' D0 values for epidermal cells in different species generally range from 100-140 rads. Cell maturation and ascension rates in the suprabasilar layers are largely unaffected. A regenerative phase of cell replacement, characterized by sharply increased cell replication rates, occurs from the 3rd to 5th postradiation weeks. The postregenerative phase of hyperplasia reflects a temporary overshoot of cell density above control levels; a subsequent decrease in hyperplasia indicates feedback control of cellular proliferation. Postradiation changes in the highly proliferative anagen hair matrix cell populations result in hair dysplasia, slowed growth rates, impaired metabolic processes, and alopecia. Dosages of 700-800 rads or more induce some degree of permanent hair loss. G0 telogen matrix cells are 2-3 times more radioresistant than proliferating anagen matrix cells, but may ''store'' radiation damage for prolonged periods. Altered matrix cell uptake of amino acids, the incidence of dysplasia, and the degree of alopecia occurring after irradiation have all been used as quantitative biological end-points for the general study of cellular radiation effects, as well as studies on the enhancement of or protection against radiation damage provided by certain pharmacologic or physical agents

  13. Quantum features of natural cellular automata

    CERN Document Server

    Elze, Hans-Thomas

    2016-01-01

    Cellular automata can show well known features of quantum mechanics, such as a linear rule according to which they evolve and which resembles a discretized version of the Schroedinger equation. This includes corresponding conservation laws. The class of "natural" Hamiltonian cellular automata is based exclusively on integer-valued variables and couplings and their dynamics derives from an Action Principle. They can be mapped reversibly to continuum models by applying Sampling Theory. Thus, "deformed" quantum mechanical models with a finite discreteness scale $l$ are obtained, which for $l\\rightarrow 0$ reproduce familiar continuum results. We have recently demonstrated that such automata can form "multipartite" systems consistently with the tensor product structures of nonrelativistic many-body quantum mechanics, while interacting and maintaining the linear evolution. Consequently, the Superposition Principle fully applies for such primitive discrete deterministic automata and their composites and can produce...

  14. Enforcement actions: Significant actions resolved

    International Nuclear Information System (INIS)

    This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (October--December 1990) and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to licensees with respect to these enforcement actions. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication

  15. Enforcement actions: Significant actions resolved

    International Nuclear Information System (INIS)

    This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (January--March 1992) and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to licensees with respect to these enforcement actions. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication

  16. Enforcement actions: Significant actions resolved

    International Nuclear Information System (INIS)

    This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (October--December 1992) and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to licensees with respect to these enforcement actions. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication

  17. Enforcement actions: Significant actions resolved

    International Nuclear Information System (INIS)

    This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (April-June 1991) and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to licensees with respect to these enforcement actions. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication

  18. Enforcement actions: Significant actions resolved

    International Nuclear Information System (INIS)

    This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (July--September 1989) and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to licensees with respect to these enforcement actions. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication

  19. Enforcement actions: Significant actions resolved

    International Nuclear Information System (INIS)

    This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (April--June 1992) and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to licensees with respect to these enforcement actions. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication

  20. Enforcement actions: Significant actions resolved

    International Nuclear Information System (INIS)

    This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (January--March 1993) and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to licensees with respect to these enforcement actions. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication

  1. Enforcement actions: Significant actions resolved

    International Nuclear Information System (INIS)

    This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (July--September 1990) and includes copies of letters, notices, and orders sent by the Nuclear Regulatory Commission to licensees with respect to these enforcement actions. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication

  2. Enforcement actions: Significant actions resolved

    International Nuclear Information System (INIS)

    This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (January--March 1991) and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to licensees with respect to these enforcement actions. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication

  3. Enforcement actions: Significant actions resolved

    International Nuclear Information System (INIS)

    This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (April--June 1990) and includes copies of letters, notices, and orders sent by the Nuclear Regulatory Commission to licensees with respect to these enforcement actions. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication

  4. Enforcement actions: Significant actions resolved

    International Nuclear Information System (INIS)

    This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (July--September 1993) and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to licensees with respect to these enforcement actions. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication

  5. Enforcement actions: Significant actions resolved

    International Nuclear Information System (INIS)

    This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (July--September 1991) and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to licensees with respect to these enforcement actions. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication

  6. Enforcement actions: Significant actions resolved

    International Nuclear Information System (INIS)

    This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (October--December 1991) and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to licensees with respect to these enforcement actions. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication

  7. Enforcement actions: Significant actions resolved

    International Nuclear Information System (INIS)

    This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (October--December 1989) and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to licensees with respect to these enforcement actions. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, so that actions can be taken to improve safety by avoiding future violations similar to those described in this publication

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

    International Nuclear Information System (INIS)

    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). - Highlights: • Alpha emission rates in teeth from smokers slightly higher than non-smokers. • Difference between alpha rates in male and female tooth not statistically significant. • Alpha particles have the same effect at any age. • Difference between alpha rates in bones was statistically significant

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

    Science.gov (United States)

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

    2016-01-01

    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.

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

    Science.gov (United States)

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

    2014-03-01

    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).

  11. Current (1984) status of the study of 226Ra and 228Ra in humans at the Center for Human Radiobiology

    International Nuclear Information System (INIS)

    The Center for Human Radiobiology has identified 5784 persons by name and type of exposure to 226Ra and 228Ra. Included are 4863 dial painters (mostly women) and non-laboratory employees of the radium dial industry, 410 laboratory workers, 399 persons who received radium for supposed therapeutic effects, and 112 in other categories. Body contents of radium have been measured in 1916 of the dial workers and about one-half of the subjects in the other groups. Bone sarcomas, carcinomas of the paranasal sinuses and mastoids, and deterioration of skeletal tissue are still the only effects unequivocally attributable to internal radium. Excess leukemias have not been observed and other malignancies, if in excess, appear more likely to be related to external gamma radiation or radon than to internal radium. Positive correlations with radium burdens have been found for the incidence of benign exostoses among subjects exposed to radium before age 18 and for shortened latency of ocular cataracts. 27 references, 3 figures, 5 tables

  12. Monte Carlo application based on GEANT4 toolkit to simulate a laser–plasma electron beam line for radiobiological studies

    International Nuclear Information System (INIS)

    We report on the development of a Monte Carlo application, based on the GEANT4 toolkit, for the characterization and optimization of electron beams for clinical applications produced by a laser-driven plasma source. The GEANT4 application is conceived so as to represent in the most general way the physical and geometrical features of a typical laser-driven accelerator. It is designed to provide standard dosimetric figures such as percentage dose depth curves, two-dimensional dose distributions and 3D dose profiles at different positions both inside and outside the interaction chamber. The application was validated by comparing its predictions to experimental measurements carried out on a real laser-driven accelerator. The work is aimed at optimizing the source, by using this novel application, for radiobiological studies and, in perspective, for medical applications. - Highlights: • Development of a Monte Carlo application based on GEANT4 toolkit. • Experimental measurements carried out with a laser-driven acceleration system. • Validation of Geant4 application comparing experimental data with the simulated ones. • Dosimetric characterization of the acceleration system

  13. Radiobiological analysis of region with higher radiation background. The effect of the background on the isomorphism of some enzymes

    International Nuclear Information System (INIS)

    An attempt is made to establish the the time when the prolong impact of slightly increased radiation background get over the compensator mechanisms of living systems. The object of investigation was the ecosystem of the Bay of Wromos (Black Sea, BG) and its surroundings where the flotation slack from an uranium mine was disposed. radioactivity. The following radiobiological picture of the site is obtained according to measurements performed: the alpha-activity of the beach sands is higher than one of the slack and is different in plants; the beta-activity is higher compared to controls in all samples investigated; the gamma spectra show high concentration of the members of U-238 and Th-232 series. The biological effect provoked by this heightened radiation background is studied by means of the isoenzymes as indicators of changes on molecular level. The isoenzyme spectra of lactate dehydrogenase and butyrol dehydrogenase is studied by vertical electrophoresis. The following species are tested: Tettigonia candata charp, Galliptumus italicus, Grillus campestris and Lumbicus terrestrial. An increase in activity and quantity of enzymes as well as changes of their isoenzyme spectra is observed. Calliptumus italicus could be used as a bio indicator of contamination, as it show better separation of the LDH and BDH-isoforms of LDH and BDH, and is more wide-spread. The increase in activity and quantity of some isoenzyme fractions in the conditions of this experiment is one of the possible mechanisms for increase in radioresistance of the living systems. 3 tabs., 2 figs., 8 refs

  14. Current (1984) status of the study of 226Ra and 228Ra in humans at the Center for Human Radiobiology

    International Nuclear Information System (INIS)

    The Center for Human Radiobiology has identified 5784 persons by name and type of exposure to 226Ra and 228Ra. Included are 4863 dial painters (mostly women) and non-laboratory employees of the radium dial industry, 410 laboratory workers, 399 persons who received radium for supposed therapeutic effects, and 112 in other categories. Body contents of radium have been measured in 1916 of the dial workers and about one-half of the subjects in the other groups. Bone sarcomas, carcinomas of the paranasal sinuses and mastoids, and deterioration of skeletal tissue are still the only effects unequivocally attributable to internal radium. Excess leukemias have not been observed and other malignancies, if in excess, appear more likely to be related to external gamma radiation or radon than to internal radium. Positive correlations with radium burdens have been found for the incidence of benign exostoses among subjects exposed to radium before age 18 and for shortened latency of ocular cataracts. 26 references, 3 figures, 5 tables

  15. Monte Carlo application based on GEANT4 toolkit to simulate a laser–plasma electron beam line for radiobiological studies

    Energy Technology Data Exchange (ETDEWEB)

    Lamia, D., E-mail: debora.lamia@ibfm.cnr.it [Institute of Molecular Bioimaging and Physiology IBFM CNR – LATO, Cefalù (Italy); Russo, G., E-mail: giorgio.russo@ibfm.cnr.it [Institute of Molecular Bioimaging and Physiology IBFM CNR – LATO, Cefalù (Italy); Casarino, C.; Gagliano, L.; Candiano, G.C. [Institute of Molecular Bioimaging and Physiology IBFM CNR – LATO, Cefalù (Italy); Labate, L. [Intense Laser Irradiation Laboratory (ILIL) – National Institute of Optics INO CNR, Pisa (Italy); National Institute for Nuclear Physics INFN, Pisa Section and Frascati National Laboratories LNF (Italy); Baffigi, F.; Fulgentini, L.; Giulietti, A.; Koester, P.; Palla, D. [Intense Laser Irradiation Laboratory (ILIL) – National Institute of Optics INO CNR, Pisa (Italy); Gizzi, L.A. [Intense Laser Irradiation Laboratory (ILIL) – National Institute of Optics INO CNR, Pisa (Italy); National Institute for Nuclear Physics INFN, Pisa Section and Frascati National Laboratories LNF (Italy); Gilardi, M.C. [Institute of Molecular Bioimaging and Physiology IBFM CNR, Segrate (Italy); University of Milano-Bicocca, Milano (Italy)

    2015-06-21

    We report on the development of a Monte Carlo application, based on the GEANT4 toolkit, for the characterization and optimization of electron beams for clinical applications produced by a laser-driven plasma source. The GEANT4 application is conceived so as to represent in the most general way the physical and geometrical features of a typical laser-driven accelerator. It is designed to provide standard dosimetric figures such as percentage dose depth curves, two-dimensional dose distributions and 3D dose profiles at different positions both inside and outside the interaction chamber. The application was validated by comparing its predictions to experimental measurements carried out on a real laser-driven accelerator. The work is aimed at optimizing the source, by using this novel application, for radiobiological studies and, in perspective, for medical applications. - Highlights: • Development of a Monte Carlo application based on GEANT4 toolkit. • Experimental measurements carried out with a laser-driven acceleration system. • Validation of Geant4 application comparing experimental data with the simulated ones. • Dosimetric characterization of the acceleration system.

  16. Integrated cellular systems

    Science.gov (United States)

    Harper, Jason C.

    The generation of new three-dimensional (3D) matrices that enable integration of biomolecular components and whole cells into device architectures, without adversely altering their morphology or activity, continues to be an expanding and challenging field of research. This research is driven by the promise that encapsulated biomolecules and cells can significantly impact areas as diverse as biocatalysis, controlled delivery of therapeutics, environmental and industrial process monitoring, early warning of warfare agents, bioelectronics, photonics, smart prosthetics, advanced physiological sensors, portable medical diagnostic devices, and tissue/organ replacement. This work focuses on the development of a fundamental understanding of the biochemical and nanomaterial mechanisms that govern the cell directed assembly and integration process. It was shown that this integration process relies on the ability of cells to actively develop a pH gradient in response to evaporation induced osmotic stress, which catalyzes silica condensation within a thin 3D volume surrounding the cells, creating a functional bio/nano interface. The mechanism responsible for introducing functional foreign membrane-bound proteins via proteoliposome addition to the silica-lipid-cell matrix was also determined. Utilizing this new understanding, 3D cellular immobilization capabilities were extended using sol-gel matrices endowed with glycerol, trehalose, and media components. The effects of these additives, and the metabolic phase of encapsulated S. cerivisiase cells, on long-term viability and the rate of inducible gene expression was studied. This enabled the entrapment of cells within a novel microfluidic platform capable of simultaneous colorimetric, fluorescent, and electrochemical detection of a single analyte, significantly improving confidence in the biosensor output. As a complementary approach, multiphoton protein lithography was utilized to engineer 3D protein matrices in which to

  17. The Radiobiological Basis for Improvements in Radiotherapy and Low Dose Risk Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Hei, Tom K

    2009-12-09

    Overall Goal: This conference grant was proposed to organize and host an international conference at Columbia University in New York to critically assess the cellular and molecular signaling events and tissue response following radiation damage. The conference would also serve as a venue to play tribute to the more than forty years contributions made by Professor Eric J. Hall to the radiation biology field. The goals of the meeting were to examine tumor hypoxia and sensitizer development; recent advances made in clinical radiotherapy; addressed several low dose phenomena, including genomic instability and bystander effects that are important in radiation risk assessment. Study and Results: The symposium was held on October 13th and 14th, 2008 at the Alfred Lerner Hall in the Morningside campus of Columbia University. The symposium, entitled “From Beans to Genes: A Forty Year Odyssey in Radiation Biology” was attended by more than 120 faculty, scientists, clinicians, fellows and students. The symposium, spanned over a day and a half, covered four scientific themes. These included tumor hypoxia and radiosensitizers; low dose radiation response; radiation biology in the practice of radiotherapy, and radiation hazard in space and genetic predisposition to cancer. The program of the symposium is as follow:

  18. Glioblastoma stem cells: radiobiological response to ionising radiations of different qualities

    International Nuclear Information System (INIS)

    Glioblastoma multiform (GBM) is the most common and malignant primary brain tumour, with very poor prognosis. The high recurrence rate and failure of conventional treatments are expected to be related to the presence of radio-resistant cancer stem cells (CSCs) inside the tumour mass. CSCs can both self-renew and differentiate into the heterogeneous lineages of cancer cells. Recent evidence showed a higher effectiveness of C-ions and protons in inactivating CSCs, suggesting a potential advantage of Hadrontherapy compared with conventional radiotherapy for GBM treatment. To investigate the mechanisms involved in the molecular and cellular responses of CSCs to ionising radiations, two GBM stem cell (GSC) lines, named lines 1 and 83, which were derived from patients with different clinical outcomes and having different metabolic profiles (as shown by NMR spectroscopy), were irradiated with 137Cs photons and with protons or C-ions of 62 MeV u-1 in the dose range of 5- 40 Gy. The biological effects investigated were: cell death, cell cycle progression, and DNA damage induction and repair. Preliminary results show a different response to ionising radiation between the two GSC lines for the different end points investigated. Further experiments are in progress to consolidate the data and to get more insights on the influence of radiation quality. (authors)

  19. Glioblastoma stem cells: radiobiological response to ionising radiations of different qualities.

    Science.gov (United States)

    Pecchia, I; Dini, V; Ricci-Vitiani, L; Biffoni, M; Balduzzi, M; Fratini, E; Belli, M; Campa, A; Esposito, G; Cirrone, G; Romano, F; Stancampiano, C; Pelacchi, F; Pallini, R; Tabocchini, M A

    2015-09-01

    Glioblastoma multiforme (GBM) is the most common and malignant primary brain tumour, with very poor prognosis. The high recurrence rate and failure of conventional treatments are expected to be related to the presence of radio-resistant cancer stem cells (CSCs) inside the tumour mass. CSCs can both self-renew and differentiate into the heterogeneous lineages of cancer cells. Recent evidence showed a higher effectiveness of C-ions and protons in inactivating CSCs, suggesting a potential advantage of Hadrontherapy compared with conventional radiotherapy for GBM treatment. To investigate the mechanisms involved in the molecular and cellular responses of CSCs to ionising radiations, two GBM stem cell (GSC) lines, named lines 1 and 83, which were derived from patients with different clinical outcomes and having different metabolic profiles (as shown by NMR spectroscopy), were irradiated with (137)Cs photons and with protons or C-ions of 62 MeV u(-1) in the dose range of 5-40 Gy. The biological effects investigated were: cell death, cell cycle progression, and DNA damage induction and repair. Preliminary results show a different response to ionising radiation between the two GSC lines for the different end points investigated. Further experiments are in progress to consolidate the data and to get more insights on the influence of radiation quality. PMID:25969527

  20. Micro-fluidic module for blood cell separation for gene expression radiobiological assays

    International Nuclear Information System (INIS)

    Advances in molecular techniques have improved discovery of biomarkers associated with radiation exposure. Gene expression techniques have been demonstrated as effective tools for biodosimetry, and different assay platforms with different chemistries are now available. One of the main challenges is to integrate the sample preparation processing of these assays into micro-fluidic platforms to be fully automated for point-of-care medical countermeasures in the case of a radiological event. Most of these assays follow the same workflow processing that comprises first the collection of blood samples followed by cellular and molecular sample preparation. The sample preparation is based on the specific reagents of the assay system and depends also on the different subsets of cells population and the type of biomarkers of interest. In this article, the authors present a module for isolation of white blood cells from peripheral blood as a prerequisite for automation of gene expression assays on a micro-fluidic cartridge. For each sample condition, the gene expression platform can be adapted to suit the requirements of the selected assay chemistry (authors)

  1. Multiuser Cellular Network

    CERN Document Server

    Bao, Yi; Chen, Ming

    2011-01-01

    Modern radio communication is faced with a problem about how to distribute restricted frequency to users in a certain space. Since our task is to minimize the number of repeaters, a natural idea is enlarging coverage area. However, coverage has restrictions. First, service area has to be divided economically as repeater's coverage is limited. In this paper, our fundamental method is to adopt seamless cellular network division. Second, underlying physics content in frequency distribution problem is interference between two close frequencies. Consequently, we choose a proper frequency width of 0.1MHz and a relevantly reliable setting to apply one frequency several times. We make a few general assumptions to simplify real situation. For instance, immobile users yield to homogenous distribution; repeaters can receive and transmit information in any given frequency in duplex operation; coverage is mainly decided by antenna height. Two models are built up to solve 1000 users and 10000 users situations respectively....

  2. A Computational Model of Cellular Response to Modulated Radiation Fields

    International Nuclear Information System (INIS)

    Purpose: To develop a model to describe the response of cell populations to spatially modulated radiation exposures of relevance to advanced radiotherapies. Materials and Methods: A Monte Carlo model of cellular radiation response was developed. This model incorporated damage from both direct radiation and intercellular communication including bystander signaling. The predictions of this model were compared to previously measured survival curves for a normal human fibroblast line (AGO1522) and prostate tumor cells (DU145) exposed to spatially modulated fields. Results: The model was found to be able to accurately reproduce cell survival both in populations which were directly exposed to radiation and those which were outside the primary treatment field. The model predicts that the bystander effect makes a significant contribution to cell killing even in uniformly irradiated cells. The bystander effect contribution varies strongly with dose, falling from a high of 80% at low doses to 25% and 50% at 4 Gy for AGO1522 and DU145 cells, respectively. This was verified using the inducible nitric oxide synthase inhibitor aminoguanidine to inhibit the bystander effect in cells exposed to different doses, which showed significantly larger reductions in cell killing at lower doses. Conclusions: The model presented in this work accurately reproduces cell survival following modulated radiation exposures, both in and out of the primary treatment field, by incorporating a bystander component. In addition, the model suggests that the bystander effect is responsible for a significant portion of cell killing in uniformly irradiated cells, 50% and 70% at doses of 2 Gy in AGO1522 and DU145 cells, respectively. This description is a significant departure from accepted radiobiological models and may have a significant impact on optimization of treatment planning approaches if proven to be applicable in vivo.

  3. Action Research

    Science.gov (United States)

    Milton-Brkich, Katie Lynn; Shumbera, Kristen; Beran, Becky

    2010-01-01

    Defined as "any systemic inquiry conducted by teachers... for the purpose of gathering information about how their particular schools operate, how they teach, and how their students learn" (Mertler, 2009), "action research" is empowering and professional research done by teachers to inform and improves their own practices. Although there are many…

  4. China's Actions

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    @@ China's National Development and Reform Commission publicized the country's policies and actions for addressing climate change in a report released on November 26,2009.The report highlighted China's efforts in cutting greenhouse gas emissions in 2009 by: (1)Rigorously checking the blind expansion of its energy-and pollution-intensive industries.

  5. Proceedings of 6th International Microbeam Workshop/12th L.H. Gray Workshop Microbeam Probes of Cellular Radiation Response

    International Nuclear Information System (INIS)

    The extended abstracts which are submitted here present a summary of the proceedings of the 6th International Workshop/12th LH Gray Workshop: Microbeam Probes of Cellular Radiation Response, held at St. Catherine's College, University of Oxford, UK on March, 29th-31st, 2003. In 1993 the 4th LH Gray Workshop entitled ''Microbeam Probes of Cellular Radiation Response'' was held at the Gray Cancer Institute in Northwood. This was organized by Prof BD Michael, Dr M. Folkard and Dr KM Prise and brought together 40 participants interested in developing and applying new microbeam technology to problems in radiation biology (1). The workshop was an undoubted success and has spawned a series of subsequent workshops every two years. In the past, these workshops have been highly successful in bringing together groups interested in developing and applying micro-irradiation techniques to the study of cell and tissue damage by ionizing radiations. Following the first microbeam workshop, there has been a rapid growth in the number of centres developing radiobiology microbeams, or planning to do so and there are currently 15-20 worldwide. Much of the recent research using microbeams has used them to study low-dose effects and ''non-targeted'' responses such bystander effects, genomic instability and adaptive responses. The goal of the 6th workshop was to build on our knowledge of the development of microbeam approaches and the application to radiation biology in the future with the meeting stretching over a 3 day period. Over 80 participants reviewed the current state of radiobiology microbeam research worldwide and reported on new technological developments both in the fields of physics and biology

  6. Never-ageing cellular senescence

    OpenAIRE

    Ogrunc, Müge; d’Adda di Fagagna, Fabrizio

    2011-01-01

    Cellular senescence was historically discovered as a form of cellular ageing of in vitro cultured cells. It has been under the spotlight following the evidence of oncogene-induced senescence in vivo and its role as a potent tumour suppressor mechanism. Presently, a PubMed search using keywords ‘cellular senescence and cancer’ reveals 8398 number of references (by April 2011) showing that while our knowledge of senescence keeps expanding, the complexity of the phenomenon keeps us – researchers...

  7. The State of Cellular Probes

    OpenAIRE

    Yim, Youngbin

    2003-01-01

    Cellular probe technology is one of several potentially promising technologies for obtaining accurate travel time information. In 1996, the Federal Communications Commission (FCC) mandated E911 requirements that cellular location be provided when 911 emergency calls come in to emergency management authorities. The E911 requirements allow 50 -300 meters from the emergency call location, depending on the type of cellular phone technology used and whether handset-based or network-based solutions...

  8. Application of radiobiological techniques in studying antioxidant mechanisms: evaluation of their radioprotective, antioxidative and antiviral activities

    International Nuclear Information System (INIS)

    In the medical field, the oxidation phenomenon is the source of several pathologies (diabetes, cystic fibrosis, cancers,...). The natural oxidants are used as food preserving and skin ageing moderators. Several plant extracts with antioxidant activity were studied, this important antioxidant activity is probably due to their richness of compounds: polyphenols, phenolic acids, tocopherols, carotenoids, flavonoids,... Many techniques for evaluation and reactional mechanism study of the antioxidative activity are used. After selection, extraction, fractionation, activity screening, chemical analyses of molecules contained in the best active extracts, biological properties research of isolated redox pharmacophore, we have : - determined the structure of active products by spectroscopy and chromatography; - studied the antioxidative properties by EPR and spin trapping of the obtained extracts and molecules. The results of this first part of our work consists in evaluating the antioxidative degree of a great number of natural active principles, extracted from moroccan plants and pur obtained products. The second part consists in studying the action mechanisms using the LDL labelling (F. M.)

  9. Cellular bioluminescence imaging.

    Science.gov (United States)

    Welsh, David K; Noguchi, Takako

    2012-08-01

    Bioluminescence imaging of live cells has recently been recognized as an important alternative to fluorescence imaging. Fluorescent probes are much brighter than bioluminescent probes (luciferase enzymes) and, therefore, provide much better spatial and temporal resolution and much better contrast for delineating cell structure. However, with bioluminescence imaging there is virtually no background or toxicity. As a result, bioluminescence can be superior to fluorescence for detecting and quantifying molecules and their interactions in living cells, particularly in long-term studies. Structurally diverse luciferases from beetle and marine species have been used for a wide variety of applications, including tracking cells in vivo, detecting protein-protein interactions, measuring levels of calcium and other signaling molecules, detecting protease activity, and reporting circadian clock gene expression. Such applications can be optimized by the use of brighter and variously colored luciferases, brighter microscope optics, and ultrasensitive, low-noise cameras. This article presents a review of how bioluminescence differs from fluorescence, its applications to cellular imaging, and available probes, optics, and detectors. It also gives practical suggestions for optimal bioluminescence imaging of single cells.

  10. Ex-RadTM (ON 01210) - a novel radioprotectant with a unique mechanism of action : physico-chemical characterization, distribution and efficacy in rodents

    International Nuclear Information System (INIS)

    The most elusive goal in radiobiology has been the development of an orally active drug that can mitigate the effects of ionizing radiation in cells and tissues. Onconova has discovered a potentially orally acting compound that exhibit protein kinase inhibitory properties capable of augmenting cellular response to radiation induced damage, and thought to interfere with biological targets at either cell cycle checkpoints, apoptosis or DNA damage repair. The objective of the current studies were to determine the physico-chemical properties of the drug, drug distribution in rodents, and the efficacy in mice

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

    Science.gov (United States)

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

    2013-03-01

    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 (P< 0.05), and tumors with a 20 min delivery 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. PMID:23090953

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

    Science.gov (United States)

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

    2009-01-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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: brodin.patrik@gmail.com; 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))

    2011-08-15

    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

  14. The investigation of molecular mechanisms in photodynamic action and radiobiology with nanosecond flash photolysis and pulse radiolysis: Final report for period April 1, 1972-June 30, 1987

    International Nuclear Information System (INIS)

    Laser flash was employed to investigate initial photolysis mechanisms in enzymes and constituent aromatic amino acids. The key role of photoionization and solvated electron generation was demonstrated. The photochemistry of furocoumarins employed for phototherapy of skin diseases was investigated, emphasizing the production and subsequent reactions of singlet molecular oxygen. The photochemistry of porphyrins employed for photodynamic therapy of malignant tumors was studied, emphasizing photosensitization of model membranes, liposomes and resealed red blood cell membranes. Photosensitization in light-scattering media was investigated in a tissue model, consisting of polystyrene microspheres in an aqueous dye solution and analyzed with the diffusion approximation to radiative transfer. The diffusion approximation was employed to develop a dosimetry model for photodynamic therapy

  15. Investigation of molecular mechanisms in photodynamic action and radiobiology with nanosecond flash photolysis and pulse radiolysis. Progress report, July 1, 1976--September 30, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Grossweiner, L.I.

    1977-06-01

    Laser flash photolysis investigations on aromatic amino acids and proteins have demonstrated that monophotonic electron ejection is the major initial act, leading to e/sup -//sub aq/ and the corresponding aromatic radicals, followed by back reactions limited by available e/sup -//sub aq/ scavengers. Results with ribonuclease A, lysozyme and carboxypeptidase A have led to information about the relationship of the photoionization efficiency of aromatic residues to the microenvironment. Measurements on the decay kinetics of photoelectrons have shown that the lifetimes and their dependence on scavenger concentrations and dose are inconsistent with homogeneous reactions. A new theory is proposed in which the photoelectron diffuses through the medium as a quasi-free particle, where original pair-recombination competes with scavenging and pair-pair interactions. This theory is in good agreement with laser flash photolysis studies on I/sup -/, FE(CN)/sub 6//sup 4 -/, tryptophan and tyrosine and consistent with earlier photochemical scavenging measurements. The general analysis of radition sensitivity has been extended to suspensions of large biological targets, such as vesicles, viruses and cells, particularly where the radical diffusion length is smaller than or comparable to the collision radius. The development is exemplified with new work on inactivation of T7 bacteriophag by 25 MeV electrons and photodynamic inactivation of Saccharomyces cerevisiae. Detailed studies on yeast have shown that the sensitivity to singlet oxygen attack depends on the temperature and the culture growth phase. Spin label ESR measurements indicate that he conditions of low photosensitivity parallel low membrane fluidity.

  16. Investigation of molecular mechanisms in photodynamic action and radiobiology with nanosecond flash photolysis and pulse radiolysis. Progress report, July 1, 1975--June 30, 1976

    Energy Technology Data Exchange (ETDEWEB)

    Grossweiner, L.I.

    1976-03-01

    Flash photolysis studies have shown that exposed tyrosyl or tryptophyl residues of enzymes are photoionized at approximately the same quantum efficiency as the aqueous amino acids. Comparisons with permanent damage indicate that this primary process contributes to inactivation when a photolyzed aromatic residue is essential or is located adjacent to a catalytic, non-chromoporic residue. Studies on sensitization by the phototherapeutic drug, 8-methoxypsoralen (8-MOP), show the triplet state can lead to singlet oxygen generation and that weak binding to poly (dA-dT) suppresses this process. 8-MOP was found to be potent sensitizer of yeast photoinactivation with negligible post-irradiation recovery. Spinlable ESR measurements made on yeast cells after photodynamic treatment show that the membrane damage generated by the penetrating dye Toluidine Blue 0 is more extensive than the external dye, Eosin Y. In related ionizing radiation studies, it was found that 8-MOP is an anoxic radiosensitizer of T7 phage, attributed to enhancement of crosslinks; that complexing of eosin to lysozyme sensitizes the enzyme to oxidizing radicals; that the reactions of Br/sub 2//sup -/ and (CNS)/sub 2//sup -/ with tryptophan generate the same initial radical as uv-excited photoionization.

  17. About Strongly Universal Cellular Automata

    Directory of Open Access Journals (Sweden)

    Maurice Margenstern

    2013-09-01

    Full Text Available In this paper, we construct a strongly universal cellular automaton on the line with 11 states and the standard neighbourhood. We embed this construction into several tilings of the hyperbolic plane and of the hyperbolic 3D space giving rise to strongly universal cellular automata with 10 states.

  18. MIMO Communication for Cellular Networks

    CERN Document Server

    Huang, Howard; Venkatesan, Sivarama

    2012-01-01

    As the theoretical foundations of multiple-antenna techniques evolve and as these multiple-input multiple-output (MIMO) techniques become essential for providing high data rates in wireless systems, there is a growing need to understand the performance limits of MIMO in practical networks. To address this need, MIMO Communication for Cellular Networks presents a systematic description of MIMO technology classes and a framework for MIMO system design that takes into account the essential physical-layer features of practical cellular networks. In contrast to works that focus on the theoretical performance of abstract MIMO channels, MIMO Communication for Cellular Networks emphasizes the practical performance of realistic MIMO systems. A unified set of system simulation results highlights relative performance gains of different MIMO techniques and provides insights into how best to use multiple antennas in cellular networks under various conditions. MIMO Communication for Cellular Networks describes single-user,...

  19. Melatonin and breast cancer: cellular mechanisms, clinical studies and future perspectives

    OpenAIRE

    Grant, Stephen G.; Melan, Melissa A.; Latimer, Jean J.; Witt-Enderby, Paula A.

    2009-01-01

    Recent studies have suggested that the pineal hormone melatonin may protect against breast cancer, and the mechanisms underlying its actions are becoming clearer. Melatonin works through receptors and distinct second messenger pathways to reduce cellular proliferation and to induce cellular differentiation. In addition, independently of receptors melatonin can modulate oestrogen-dependent pathways and reduce free-radical formation, thus preventing mutation and cellular toxicity. The fact that...

  20. 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

    Energy Technology Data Exchange (ETDEWEB)

    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.

    2013-07-01

    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)

  1. Action Learning: Avoiding Conflict or Enabling Action

    Science.gov (United States)

    Corley, Aileen; Thorne, Ann

    2006-01-01

    Action learning is based on the premise that action and learning are inextricably entwined and it is this potential, to enable action, which has contributed to the growth of action learning within education and management development programmes. However has this growth in action learning lead to an evolution or a dilution of Revan's classical…

  2. Cellular systems biology profiling applied to cellular models of disease.

    Science.gov (United States)

    Giuliano, Kenneth A; Premkumar, Daniel R; Strock, Christopher J; Johnston, Patricia; Taylor, Lansing

    2009-11-01

    Building cellular models of disease based on the approach of Cellular Systems Biology (CSB) has the potential to improve the process of creating drugs as part of the continuum from early drug discovery through drug development and clinical trials and diagnostics. This paper focuses on the application of CSB to early drug discovery. We discuss the integration of protein-protein interaction biosensors with other multiplexed, functional biomarkers as an example in using CSB to optimize the identification of quality lead series compounds.

  3. Actual problems of cellular cardiomyoplasty

    Directory of Open Access Journals (Sweden)

    Bulat Kaupov

    2010-04-01

    Full Text Available The paper provides review of cellular technologies used incardiology, describes types of cellular preparations depending onsources of cells and types of compounding cells. The generalmechanisms of therapies with stem cells applications are described.Use of cellular preparations for treatment of cardiovascular diseasesand is improvement of the forecast at patients with heartinsufficiency of various genesis is considered as alternative topractice with organ transplantations. Efforts of biotechnologicallaboratories are directed on search of optimum population of cellsfor application in cardiology and studying of mechanisms andfactors regulating function of cardiac stem cells.

  4. Template learning of cellular neural network using genetic programming.

    Science.gov (United States)

    Radwan, Elsayed; Tazaki, Eiichiro

    2004-08-01

    A new learning algorithm for space invariant Uncoupled Cellular Neural Network is introduced. Learning is formulated as an optimization problem. Genetic Programming has been selected for creating new knowledge because they allow the system to find new rules both near to good ones and far from them, looking for unknown good control actions. According to the lattice Cellular Neural Network architecture, Genetic Programming will be used in deriving the Cloning Template. Exploration of any stable domain is possible by the current approach. Details of the algorithm are discussed and several application results are shown.

  5. [Cellular adaptation and cancerogenesis].

    Science.gov (United States)

    La Torre, F; Silpigni, A; Tomasello, R; Picone, G S; La Torre, I; Aragona, M

    1998-06-01

    The paper describes the main adaptive mechanisms involved in the carcinogenic process. As a result of the action of carcinogenic agents (physical, chemical, biological), and in relation to the functional status of the affected cells, a number of systems are triggered off: detoxification and conjugation systems, the metabolisation of the said agents, DNA repairing enzymes, increased shock proteins (HSP), the induction of clonal proliferation. All these systems are valuable to the survival of the body and the species and culminate in the apoptosis of damaged cells as the last attempt at adaptation of a social kind for the good of the body. When these compensation mechanisms prove ineffective, imprecise or are exceeded by cell adaptive capacity, the resulting structural and functional alterations trigger off (induction) a very long process which often lasts between one and two thirds of the body's life, in various stages, multistep and multifactorial: this neoplastic transformation leads to a purposeless, egoistic, anarchic proliferation of cells which wish to survive at all costs, even to the detriment of the body of which they form part. Following the exhaustion of cell adaptive defences, there is an accumulation of additional genetic alterations (promotion and progression), the cells become manifestly neoplastic and continue their egoistic adaptation, according to the laws of natural selection: the cells which survive are those which adapt best to the hostile environment of the host's body, which are unaffected by proliferation control mechanisms (contact inhibition, differentiation factors, apoptosis, etc.), which make the best of the growth factors present in their microenvironment, which accomplish the so-called decathlon of the metastatization process, namely acquiring new capacities which can overcome the basal membrane, invade tissues to which they are attracted and continue to proliferate. Manifestly neoplastic cells become not self at a later stage

  6. 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

    Directory of Open Access Journals (Sweden)

    Zoi Thrapsanioti

    2013-01-01

    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.

  7. Consequences of anorectal cancer atlas implementation in the cooperative group setting: Radiobiologic analysis of a prospective randomized in silico target delineation study

    International Nuclear Information System (INIS)

    Purpose: The aim of this study is to ascertain the subsequent radiobiological impact of using a consensus guideline target volume delineation atlas. Materials and methods: Using a representative case and target volume delineation instructions derived from a proposed IMRT rectal cancer clinical trial, gross tumor volume (GTV) and clinical/planning target volumes (CTV/PTV) were contoured by 13 physician observers (Phase 1). The observers were then randomly assigned to follow (atlas) or not-follow (control) a consensus guideline/atlas for anorectal cancers, and instructed to re-contour the same case (Phase 2). Results: The atlas group was found to have increased tumor control probability (TCP) after the atlas intervention for both the CTV (p < 0.0001) and PTV1 (p = 0.0011) with decreasing normal tissue complication probability (NTCP) for small intestine, while the control group did not. Additionally, the atlas group had reduced variance in TCP for all target volumes and reduced variance in NTCP for the bowel. In Phase 2, the atlas group had increased TCP relative to the control for CTV (p = 0.03). Conclusions: Visual atlas and consensus treatment guideline usage in the development of rectal cancer IMRT treatment plans reduced the inter-observer radiobiological variation, with clinically relevant TCP alteration for CTV and PTV volumes

  8. Radiobiological Characterization of Two Photon-Beam Energies 6 and 15 MV used in Radiotherapy From Linear Accelerator

    International Nuclear Information System (INIS)

    The main objective of this study is to perform radiobiological characterization of two different photon beam energies, 6 MV and 15 MV, from linear accelerator used in radiotherapy, with special regard to late effects of radiation. Two end-points, namely cell survival and micronucleus induction were used for the characterization. Chinese hamster V 79 lung fibroblast cell line to prepare cell culture and to perform the innervate experiments. chromosomes number was counted and found to be 22 chromosomes per cell, this result is in complete agreement with expected 11 pairs of chromosomes representing the genome of this species. Cells were kept in confluent growth for two days and then exposed to two photon beam energies, 6 and 15 MV respectively. Different dose rates were used for the two beam energies, 0.25, 0.5, 1.0, 2.0, 4.0, 7.0 Gy. Cells were counted immediately after irradiation and re seeded, the seeded number of cells was calculated to the dose rate used. Another set of unirradiated cells treated the same as the experimental set was used as a control group. The plating efficiency (PE) was calculated for the control group, then cells were incubated at 37oC for 6 days to construct the survival curve, five samples were counted per dose and the mean was calculated. The two survival curves are similar for photon beam energies (6 and 15 MV) and the surviving fraction was decreased with dose rate. The two curves showed similar values of α and β parameters, this result is expected for the same radiation type (X-ray). For the micronuclei assay three samples for each dose were seeded and incubated at 37oC for 24 hours then Cytochalasin-B was added to block cells in cytokinesis phase of the mitosis. The micronuclei number was counted and plotted with dose. A significant positive correlation was found between dose and micronuclei frequency (P=0.00), moreover, the micronuclei frequency is relatively higher with 15 MV compared with 6 MV energy. This indicates the presence

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-06-15

    %-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.

  10. Cellular mechanisms during vascular development

    OpenAIRE

    Blum, Yannick

    2012-01-01

    The vascular system is an essential organ in vertebrate animals and provides the organism with enough oxygen and nutrients. It is composed of an interconnected network of blood vessels, which form using a number of different morphogenetic mechanisms. Angiogenesis describes the formation of new blood vessels from preexisting vessels. A number of molecular pathways have been shown to be essential during angiogenesis. However, cellular architecture of blood vessels as well as cellular mechanisms...

  11. Cellular automaton for chimera states

    OpenAIRE

    García-Morales, Vladimir

    2016-01-01

    A minimalistic model for chimera states is presented. The model is a cellular automaton (CA) which depends on only one adjustable parameter, the range of the nonlocal coupling, and is built from elementary cellular automata and the majority (voting) rule. This suggests the universality of chimera-like behavior from a new point of view: Already simple CA rules based on the majority rule exhibit this behavior. After a short transient, we find chimera states for arbitrary initial conditions, the...

  12. Determination of the accuracy for targeted irradiations of cellular substructures at SNAKE

    Energy Technology Data Exchange (ETDEWEB)

    Siebenwirth, C. [Department of Radiation Oncology, Klinikum rechts der Isar, Technische Universität München, Munich (Germany); Institut für Angewandte Physik und Messtechnik (LRT2), Universität der Bundeswehr München, Neubiberg (Germany); Greubel, C. [Institut für Angewandte Physik und Messtechnik (LRT2), Universität der Bundeswehr München, Neubiberg (Germany); Drexler, S.E. [Department of Radiation Oncology, Ludwig-Maximilians-Universität München, Munich (Germany); Girst, S.; Reindl, J. [Institut für Angewandte Physik und Messtechnik (LRT2), Universität der Bundeswehr München, Neubiberg (Germany); Walsh, D.W.M. [Institut für Angewandte Physik und Messtechnik (LRT2), Universität der Bundeswehr München, Neubiberg (Germany); Department of Radiation Oncology, Klinikum rechts der Isar, Technische Universität München, Munich (Germany); Dollinger, G. [Institut für Angewandte Physik und Messtechnik (LRT2), Universität der Bundeswehr München, Neubiberg (Germany); Friedl, A.A. [Department of Radiation Oncology, Ludwig-Maximilians-Universität München, Munich (Germany); and others

    2015-04-01

    In the last 10 years the ion microbeam SNAKE, installed at the Munich 14 MV tandem accelerator, has been successfully used for radiobiological experiments by utilizing pattern irradiation without targeting single cells. Now for targeted irradiation of cellular substructures a precise irradiation device was added to the live cell irradiation setup at SNAKE. It combines a sub-micrometer single ion irradiation facility with a high resolution optical fluorescence microscope. Most systematic errors can be reduced or avoided by using the same light path in the microscope for beam spot verification as well as for and target recognition. In addition online observation of the induced cellular responses is possible. The optical microscope and the beam delivering system are controlled by an in-house developed software which integrates the open-source image analysis software, CellProfiler, for semi-automatic target recognition. In this work the targeting accuracy was determined by irradiation of a cross pattern with 55 MeV carbon ions on nucleoli in U2OS and HeLa cells stably expressing a GFP-tagged repair protein MDC1. For target recognition, nuclei were stained with Draq5 and nucleoli were stained with Syto80 or Syto83. The damage response was determined by live-cell imaging of MDC1-GFP accumulation directly after irradiation. No systematic displacement and a random distribution of about 0.7 μm (SD) in x-direction and 0.8 μm (SD) in y-direction were observed. An independent analysis after immunofluorescence staining of the DNA damage marker yH2AX yielded similar results. With this performance a target with a size similar to that of nucleoli (i.e. a diameter of about 3 μm) is hit with a probability of more than 80%, which enables the investigation of the radiation response of cellular subcompartments after targeted ion irradiation in the future.

  13. Mathematical Modeling of Cellular Metabolism.

    Science.gov (United States)

    Berndt, Nikolaus; Holzhütter, Hermann-Georg

    2016-01-01

    Cellular metabolism basically consists of the conversion of chemical compounds taken up from the extracellular environment into energy (conserved in energy-rich bonds of organic phosphates) and a wide array of organic molecules serving as catalysts (enzymes), information carriers (nucleic acids), and building blocks for cellular structures such as membranes or ribosomes. Metabolic modeling aims at the construction of mathematical representations of the cellular metabolism that can be used to calculate the concentration of cellular molecules and the rates of their mutual chemical interconversion in response to varying external conditions as, for example, hormonal stimuli or supply of essential nutrients. Based on such calculations, it is possible to quantify complex cellular functions as cellular growth, detoxification of drugs and xenobiotic compounds or synthesis of exported molecules. Depending on the specific questions to metabolism addressed, the methodological expertise of the researcher, and available experimental information, different conceptual frameworks have been established, allowing the usage of computational methods to condense experimental information from various layers of organization into (self-) consistent models. Here, we briefly outline the main conceptual frameworks that are currently exploited in metabolism research.

  14. Abstracts of papers of international scientific conference 'Fundamental and applied aspects of radiobiology: Biological effects of low doses and radioactive contamination of environment (Radioecological and medical biological consequences of the Chernobyl NPP accident)'

    International Nuclear Information System (INIS)

    The results of research works executed in Belarus, as well as in Ukraine and Russia, on various aspects of the Chernobyl problematic are given: radiation medicine and risks, radiobiological effects and their forecasting, radioecology and agricultural radiology, decontamination and radioactive wastes management, socio economic and psychological problems caused by the Chernobyl NPP accident

  15. Hierarchical Cellular Structures in High-Capacity Cellular Communication Systems

    CERN Document Server

    Jain, R K; Agrawal, N K

    2011-01-01

    In the prevailing cellular environment, it is important to provide the resources for the fluctuating traffic demand exactly in the place and at the time where and when they are needed. In this paper, we explored the ability of hierarchical cellular structures with inter layer reuse to increase the capacity of mobile communication network by applying total frequency hopping (T-FH) and adaptive frequency allocation (AFA) as a strategy to reuse the macro and micro cell resources without frequency planning in indoor pico cells [11]. The practical aspects for designing macro- micro cellular overlays in the existing big urban areas are also explained [4]. Femto cells are inducted in macro / micro / pico cells hierarchical structure to achieve the required QoS cost effectively.

  16. A Mean Field Game Approach to Scheduling in Cellular Systems

    OpenAIRE

    Manjrekar, Mayank; Ramaswamy, Vinod; Shakkottai, Srinivas

    2013-01-01

    We study auction-theoretic scheduling in cellular networks using the idea of mean field equilibrium (MFE). Here, agents model their opponents through a distribution over their action spaces and play the best response. The system is at an MFE if this action is itself a sample drawn from the assumed distribution. In our setting, the agents are smart phone apps that generate service requests, experience waiting costs, and bid for service from base stations. We show that if we conduct a second-pr...

  17. Research in radiobiology

    Energy Technology Data Exchange (ETDEWEB)

    Jee, W.S.S.

    1990-07-15

    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)

  18. Neutron radiobiology revisited

    International Nuclear Information System (INIS)

    The present paper reviews the experimental results of normal tissue and tumour studies in animals. The dose per fraction dependence of the RBE in normal tissues has been long recognised, together with the steeper increase of RBE at low doses for late responding tissues compared with acute reactions. The dose dependence for tumours is more complex, because of hypoxia and reoxygenation, as well as differences in repair capability after high LET damage. A comparison of tumour and normal tissue RBE values shows that there is little experimental evidence for a therapeutic advantage at clinically relevant doses. In particular, the RBE for slow growing tumours is even lower than that for the faster growing mouse tumours. The reasons for the loss of expected neutron benefits in clinically relevant experiments are discussed. The disappointing prospects for neutrons are contrasted with the current multifactorial approaches to overcoming resistance to more conventional low LET radiations, including acceleration, hyperfractionation and several types of hypoxic cell radiosensitizers. (orig.)

  19. Meson radiobiology and therapy

    International Nuclear Information System (INIS)

    High-linear energy transfer radiation (neutrons, heavy ions, and pions) have a greater relative biological effectiveness than low-linear energy transfer radiation by depositing a high density of ionization in irradiated cells. This overcomes the protective effect of oxygen; decreases the variation in sensitivity among the several stages of the cell cycles; and, inhibits the repair of sublethal damage as compared to x-rays, gamma rays, electrons and protons. Negative pi mesons (pions), appear particularly suited for radiation therapy as their penetration and depth-dose profiles lend themselves to shaping the high dose area to the tumor size and location. Preliminary biological experiments with pions produced at the Los Alamos Meson Physics Facility studied cell survival at various radiation depths and cell cycle sensitivity. Histologic study of data from the first human experiments indicated severe tumor cell destruction by pions as compared to x-rays in treating malignant melanoma skin nodules, without increased effects on dermal elements. (U.S.)

  20. Continuum representations of cellular solids

    Energy Technology Data Exchange (ETDEWEB)

    Neilsen, M.K.

    1993-09-01

    Cellular materials consist of interconnected struts or plates which form cells. The struts or plates are constructed from a variety of metals, polymers, ceramics and wood products. Cellular materials are often used in impact limiters for shipping containers to protect the contents from accidental impact events. These materials exhibit a variety of complex behavior when subjected to crushing loads. This research focuses on the development of continuum representations of cellular solids that can be used in the finite element analysis of shipping container accidents. A significant portion of this work is the development of a new methodology to relate localized deformations to appropriate constitutive descriptions. This methodology provides the insight needed to select constitutive descriptions for cellular solids that capture the localized deformations that are observed experimentally. Constitutive relations are developed for two different cellular materials, aluminum honeycomb and polyurethane foam. These constitutive relations are based on plasticity and continuum damage theories. Plasticity is used to describe the permanent deformation exhibited by both aluminum honeycomb and polyurethane foam. Continuum damage is needed to capture the change in elastic parameters due to cracking of the polyurethane cell wall materials. The new constitutive description of polyurethane foam is implemented in both static and dynamic finite element codes, and analytical and numerical predictions are compared with available experimental data.

  1. Prognosis of Different Cellular Generations

    Directory of Open Access Journals (Sweden)

    Preetish Ranjan

    2013-04-01

    Full Text Available Technological advancement in mobile telephony from 1G to 3G, 4G and 5G has a very axiomatic fact that made an entire world a global village. The cellular system employs a different design approach and technology that most commercial radio and television system use. In the cellular system, the service area is divided into cells and a transmitter is designed to serve an individual cell. The system seeks to make efficient use of available channels by using low-power transmitters to allow frequency reuse at a smaller distance. Maximizing the number of times each channel can be reused in a given geographical area is the key to an efficient cellular system design. During the past three decades, the world has seen significant changes in telecommunications industry. There have been some remarkable aspects to the rapid growth in wireless communications, as seen by the large expansion in mobile systems. This paper focuses on “Past, Present & Future of Cellular Telephony” and some light has been thrown upon the technologies of the cellular systems, namely 1G, 2G, 2.5G, 3G and future generations like 4G and 5G systems as well.

  2. Ubiquitin Metabolism Affects Cellular Response to Volatile Anesthetics in Yeast

    OpenAIRE

    Wolfe, Darren; Reiner, Thomas; Keeley, Jessica L.; Pizzini, Mark; Keil, Ralph L.

    1999-01-01

    To investigate the mechanism of action of volatile anesthetics, we are studying mutants of the yeast Saccharomyces cerevisiae that have altered sensitivity to isoflurane, a widely used clinical anesthetic. Several lines of evidence from these studies implicate a role for ubiquitin metabolism in cellular response to volatile anesthetics: (i) mutations in the ZZZ1 gene render cells resistant to isoflurane, and the ZZZ1 gene is identical to BUL1 (binds ubiquitin ligase), which appears to be invo...

  3. 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

    International Nuclear Information System (INIS)

    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, σd; whilst the quantities d and σd 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 108 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 on the tcp to

  4. Theoretical models and simulation codes to investigate bystander effects and cellular communication at low doses

    Science.gov (United States)

    Ballarini, F.; Alloni, D.; Facoetti, A.; Mairani, A.; Nano, R.; Ottolenghi, A.

    Astronauts in space are continuously exposed to low doses of ionizing radiation from Galactic Cosmic Rays During the last ten years the effects of low radiation doses have been widely re-discussed following a large number of observations on the so-called non targeted effects in particular bystander effects The latter consist of induction of cytogenetic damage in cells not directly traversed by radiation most likely as a response to molecular messengers released by directly irradiated cells Bystander effects which are observed both for lethal endpoints e g clonogenic inactivation and apoptosis and for non-lethal ones e g mutations and neoplastic transformation tend to show non-linear dose responses This might have significant consequences in terms of low-dose risk which is generally calculated on the basis of the Linear No Threshold hypothesis Although the mechanisms underlying bystander effects are still largely unknown it is now clear that two types of cellular communication i e via gap junctions and or release of molecular messengers into the extracellular environment play a fundamental role Theoretical models and simulation codes can be of help in elucidating such mechanisms In the present paper we will review different available modelling approaches including one that is being developed at the University of Pavia The focus will be on the different assumptions adopted by the various authors and on the implications of such assumptions in terms of non-targeted radiobiological damage and more generally low-dose

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

    Directory of Open Access Journals (Sweden)

    Supe Sanjay

    2006-01-01

    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

  6. Adaptive stochastic cellular automata: Applications

    Science.gov (United States)

    Qian, S.; Lee, Y. C.; Jones, R. D.; Barnes, C. W.; Flake, G. W.; O'Rourke, M. K.; Lee, K.; Chen, H. H.; Sun, G. Z.; Zhang, Y. Q.; Chen, D.; Giles, C. L.

    1990-09-01

    The stochastic learning cellular automata model has been applied to the problem of controlling unstable systems. Two example unstable systems studied are controlled by an adaptive stochastic cellular automata algorithm with an adaptive critic. The reinforcement learning algorithm and the architecture of the stochastic CA controller are presented. Learning to balance a single pole is discussed in detail. Balancing an inverted double pendulum highlights the power of the stochastic CA approach. The stochastic CA model is compared to conventional adaptive control and artificial neural network approaches.

  7. Cellular automaton for chimera states

    Science.gov (United States)

    García-Morales, Vladimir

    2016-04-01

    A minimalistic model for chimera states is presented. The model is a cellular automaton (CA) which depends on only one adjustable parameter, the range of the nonlocal coupling, and is built from elementary cellular automata and the majority (voting) rule. This suggests the universality of chimera-like behavior from a new point of view: Already simple CA rules based on the majority rule exhibit this behavior. After a short transient, we find chimera states for arbitrary initial conditions, the system spontaneously splitting into stable domains separated by static boundaries, some synchronously oscillating and the others incoherent. When the coupling range is local, nontrivial coherent structures with different periodicities are formed.

  8. Cellular senescence in aging primates.

    Science.gov (United States)

    Herbig, Utz; Ferreira, Mark; Condel, Laura; Carey, Dee; Sedivy, John M

    2006-03-01

    The aging of organisms is characterized by a gradual functional decline of all organ systems. Mammalian somatic cells in culture display a limited proliferative life span, at the end of which they undergo an irreversible cell cycle arrest known as replicative senescence. Whether cellular senescence contributes to organismal aging has been controversial. We investigated telomere dysfunction, a recently discovered biomarker of cellular senescence, and found that the number of senescent fibroblasts increases exponentially in the skin of aging baboons, reaching >15% of all cells in very old individuals. In addition, the same cells contain activated ataxia-telangiectasia mutated kinase and heterochromatinized nuclei, confirming their senescent status. PMID:16456035

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

    Energy Technology Data Exchange (ETDEWEB)

    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: lydia.paredes@inin.gob.mx [Hospital Medica Sur, Departamento de Radioterapia, Puente de Piedra 150, Col. Toriello Guerra, 14050 Mexico D. F. (Mexico)

    2014-08-15

    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)

  10. Three-dimensional radiobiological dosimetry (3D-RD) with {sup 124}I PET for {sup 131}I therapy of thyroid cancer

    Energy Technology Data Exchange (ETDEWEB)

    Sgouros, George; Hobbs, Robert F.; Wahl, Richard L. [Johns Hopkins University, School of Medicine, The Russell H. Morgan Department of Radiology, Division of Nuclear Medicine, Baltimore, MD (United States); Atkins, Francis B.; Nostrand, Douglas van [The Washington Hospital Center, Division of Nuclear Medicine, Washington, DC (United States); Ladenson, Paul W. [Johns Hopkins University, School of Medicine, Department of Endocrinology, Baltimore, MD (United States)

    2011-06-15

    Radioiodine therapy of thyroid cancer was the first and remains among the most successful radiopharmaceutical (RPT) treatments of cancer although its clinical use is based on imprecise dosimetry. The positron emitting radioiodine, {sup 124}I, in combination with positron emission tomography (PET)/CT has made it possible to measure the spatial distribution of radioiodine in tumors and normal organs at high resolution and sensitivity. The CT component of PET/CT has made it simpler to match the activity distribution to the corresponding anatomy. These developments have facilitated patient-specific dosimetry (PSD), utilizing software packages such as three-dimensional radiobiological dosimetry (3D-RD), which can account for individual patient differences in pharmacokinetics and anatomy. We highlight specific examples of such calculations and discuss the potential impact of {sup 124}I PET/CT on thyroid cancer therapy. (orig.)

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

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2014-06-01

    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.

  13. Dosimetric and radiobiological comparison of CyberKnife M6™ InCise multileaf collimator over IRIS™ variable collimator in prostate stereotactic body radiation therapy

    Science.gov (United States)

    Kathriarachchi, Vindu; Shang, Charles; Evans, Grant; Leventouri, Theodora; Kalantzis, Georgios

    2016-01-01

    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 Dmax and V37Gy, rectum Dmax and 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. PMID:27217626

  14. Dosimetric and radiobiological characterizations of prostate intensity-modulated radiotherapy and volumetric-modulated arc therapy: A single-institution review of ninety cases.

    Science.gov (United States)

    Khan, Muhammad Isa; Jiang, Runqing; Kiciak, Alexander; Ur Rehman, Jalil; Afzal, Muhammad; Chow, James C L

    2016-01-01

    This study reviewed prostate volumetric-modulated arc therapy (VMAT) plans with intensity-modulated radiotherapy (IMRT) plans after prostate IMRT technique was replaced by VMAT in an institution. Characterizations of dosimetry and radiobiological variation in prostate were determined based on treatment plans of 40 prostate IMRT patients (planning target volume = 77.8-335 cm(3)) and 50 VMAT patients (planning target volume = 120-351 cm(3)) treated before and after 2013, respectively. Both IMRT and VMAT plans used the same dose-volume criteria in the inverse planning optimization. Dose-volume histogram, mean doses of target and normal tissues (rectum, bladder and femoral heads), dose-volume points (D99% of planning target volume; D30%, D50%, V30 Gy and V35 Gy of rectum and bladder; D5%, V14 Gy, V22 Gy of femoral heads), conformity index (CI), homogeneity index (HI), gradient index (GI), prostate tumor control probability (TCP), and rectal normal tissue complication probability (NTCP) based on the Lyman-Burman-Kutcher algorithm were calculated for each IMRT and VMAT plan. From our results, VMAT plan was found better due to its higher (1.05%) CI, lower (0.83%) HI and (0.75%) GI than IMRT. Comparing doses in normal tissues between IMRT and VMAT, it was found that IMRT mostly delivered higher doses of about 1.05% to the normal tissues than VMAT. Prostate TCP and rectal NTCP were found increased (1%) for VMAT than IMRT. It is seen that VMAT technique can decrease the dose-volume evaluation criteria for the normal tissues. Based on our dosimetric and radiobiological results in treatment plans, it is concluded that our VMAT implementation could produce comparable or slightly better target coverage and normal tissue sparing with a faster treatment time in prostate radiotherapy. PMID:27651562

  15. [Photodynamic modulation of cellular functions].

    Science.gov (United States)

    Li, Yuan; Jiang, Hong-Ning; Cui, Zong-Jie

    2016-08-25

    Photodynamic action, due to the rather limited lifetime (1 μs) and effective reactive distance of singlet oxygen (lysosomes or endoplasmic reticulum can modulate photodynamically subcellular functions and fine-tune protein activity by targeted photooxidation. With the newly emerged active illumination technique, simultaneous photodynamic action localized at multiple sites is now possible, and the contribution of subcellular regions to the whole cell or individual cells to a cell cluster could be quantitated. Photodynamic action with protein photosensitiser will be a powerful tool for nano-manipulation in cell physiology research. PMID:27546513

  16. Repaglinide at a cellular level

    DEFF Research Database (Denmark)

    Krogsgaard Thomsen, M; Bokvist, K; Høy, M;

    2002-01-01

    To investigate the hormonal and cellular selectivity of the prandial glucose regulators, we have undertaken a series of experiments, in which we characterised the effects of repaglinide and nateglinide on ATP-sensitive potassium ion (KATP) channel activity, membrane potential and exocytosis in ra...

  17. Analysis of cellular manufacturing systems

    NARCIS (Netherlands)

    Heragu, Sunderesh; Meng, Gang; Zijm, Henk; Ommeren, van Jan-Kees

    2001-01-01

    In this paper, we present an open queuing network modeling approach to estimate performance measures of a cellular manufacturing layout. It is assumed a layout and production data for a planning period of specified length are available. The production data takes into account, processing and handli

  18. Cellular uptake of metallated cobalamins

    DEFF Research Database (Denmark)

    Tran, MQT; Stürup, Stefan; Lambert, Ian H.;

    2016-01-01

    Cellular uptake of vitamin B12-cisplatin conjugates was estimated via detection of their metal constituents (Co, Pt, and Re) by inductively coupled plasma mass spectrometry (ICP-MS). Vitamin B12 (cyano-cob(iii)alamin) and aquo-cob(iii)alamin [Cbl-OH2](+), which differ in the β-axial ligands (CN(-...

  19. 7th International Workshop on Microbeam Probes of Cellular Radiation Response

    Energy Technology Data Exchange (ETDEWEB)

    Brenner, David J.

    2009-07-21

    The extended abstracts that follow present a summary of the Proceedings of the 7th International Workshop: Microbeam Probes of Cellular Radiation Response, held at Columbia University’s Kellogg Center in New York City on March 15–17, 2006. These International Workshops on Microbeam Probes of Cellular Radiation Response have been held regularly since 1993 (1–5). Since the first workshop, there has been a rapid growth (see Fig. 1) in the number of centers developing microbeams for radiobiological research, and worldwide there are currently about 30 microbeams in operation or under development. Single-cell/single-particle microbeam systems can deliver beams of different ionizing radiations with a spatial resolution of a few micrometers down to a few tenths of a micrometer. Microbeams can be used to addressquestions relating to the effects of low doses of radiation (a single radiation track traversing a cell or group of cells), to probe subcellular targets (e.g. nucleus or cytoplasm), and to address questions regarding the propagation of information about DNA damage (for example, the radiation-induced bystander effect). Much of the recent research using microbeams has been to study low-dose effects and ‘‘non-targeted’’ responses such as bystander effects, genomic instability and adaptive responses. This Workshop provided a forum to assess the current state of microbeam technology and current biological applications and to discuss future directions for development, both technological and biological. Over 100 participants reviewed the current state of microbeam research worldwide and reported on new technological developments in the fields of both physics and biology.

  20. Hybrid Action Systems

    DEFF Research Database (Denmark)

    Ronkko, Mauno; Ravn, Anders P.

    1997-01-01

    An action system framework is a predicate transformer based method for modelling and analysing distributed and reactive systems. The actions in action systems are statements in Dijkstra's guarded command language, and their semantics is given by predicate transformers. Recently, we introduced...... a differential action, which allows differential equations as primitive actions. The extension allows us to model hybrid systems with both continuous and discrete behaviour. The main result of this paper is an extension of such a hybrid action system with parallel composition. The extension does not change...... the original meaning of the parallel composition, and therefore also the ordinary action systems can be composed in parallel with the hybrid action systems....

  1. Cellular solidification of transparent monotectics

    Science.gov (United States)

    Kaulker, W. F.

    1986-01-01

    Understanding how liquid phase particles are engulfed or pushed during freezing of a monotectic is addressed. The additional complication is that the solid-liquid interface is nonplanar due to constitutional undercooling. Some evidence of particle pushing where the particles are the liquid phase of the montectic was already observed. Cellular freezing of the succinonitrile-glycerol system also occurred. Only a few compositions were tested at that time. The starting materials were not especially pure so that cellular interface observed was likely due to the presence of unkown impurities, the major portion of which was water. Topics addressed include: the effort of modeling the particle pushing process using the computer, establishing an apparatus for the determination of phase diagrams, and the measurement of the temperature gradients with a specimen which will solidify on the temperature gradient microscope stage.

  2. Reversibly assembled cellular composite materials.

    Science.gov (United States)

    Cheung, Kenneth C; Gershenfeld, Neil

    2013-09-13

    We introduce composite materials made by reversibly assembling a three-dimensional lattice of mass-produced carbon fiber-reinforced polymer composite parts with integrated mechanical interlocking connections. The resulting cellular composite materials can respond as an elastic solid with an extremely large measured modulus for an ultralight material (12.3 megapascals at a density of 7.2 milligrams per cubic centimeter). These materials offer a hierarchical decomposition in modeling, with bulk properties that can be predicted from component measurements and deformation modes that can be determined by the placement of part types. Because site locations are locally constrained, structures can be produced in a relative assembly process that merges desirable features of fiber composites, cellular materials, and additive manufacturing.

  3. Analysis of cellular manufacturing systems

    OpenAIRE

    Heragu, Sunderesh; Meng, Gang; Zijm, Henk; Ommeren, van, J.C.

    2001-01-01

    In this paper, we present an open queuing network modeling approach to estimate performance measures of a cellular manufacturing layout. It is assumed a layout and production data for a planning period of specified length are available. The production data takes into account, processing and handling set-up times as well as transfer and process batch size information of multiple products that flow through the system. It is assumed that two sets of discrete material handling devices are used fo...

  4. Identification of Nonstationary Cellular Automata

    Institute of Scientific and Technical Information of China (English)

    AndrewI.Adamatzky

    1992-01-01

    The principal feature of nonstationary cellular automata(NCA) is that a local transitiol rule of each cell is changed at each time step depending on neighborhood configuration at previous time step.The identification problem for NCA is extraction of local transition rules and the establishment of mechanism for changing these rules using sequence of NCA configurations.We present serial and parallel algorithms for identification of NCA.

  5. The Origins of Cellular Life

    OpenAIRE

    Schrum, Jason P.; Zhu, Ting F.; SZOSTAK, JACK W.

    2010-01-01

    Understanding the origin of cellular life on Earth requires the discovery of plausible pathways for the transition from complex prebiotic chemistry to simple biology, defined as the emergence of chemical assemblies capable of Darwinian evolution. We have proposed that a simple primitive cell, or protocell, would consist of two key components: a protocell membrane that defines a spatially localized compartment, and an informational polymer that allows for the replication and inheritance of fun...

  6. Stochastic Nature in Cellular Processes

    Institute of Scientific and Technical Information of China (English)

    刘波; 刘圣君; 王祺; 晏世伟; 耿轶钊; SAKATA Fumihiko; GAO Xing-Fa

    2011-01-01

    The importance of stochasticity in cellular processes is increasingly recognized in both theoretical and experimental studies. General features of stochasticity in gene regulation and expression are briefly reviewed in this article, which include the main experimental phenomena, classification, quantization and regulation of noises. The correlation and transmission of noise in cascade networks are analyzed further and the stochastic simulation methods that can capture effects of intrinsic and extrinsic noise are described.

  7. CELLULAR FETAL MICROCHIMERISM IN PREECLAMPSIA

    OpenAIRE

    Gammill, Hilary S; Aydelotte, Tessa M.; Guthrie, Katherine A.; Nkwopara, Evangelyn C.; Nelson, J. Lee

    2013-01-01

    Previous studies have shown elevated concentrations of free fetal deoxyribonucleic acid and erythroblasts in maternal circulation in preeclampsia compared with normal pregnancy. Pluripotent and immunocompetent fetal cells also transfer to the maternal circulation during pregnancy, but whether concentrations of fetal mononuclear cells also differed in preeclampsia was unknown. We sought to quantify cellular fetal microchimerism in maternal circulation in women with preeclampsia and healthy con...

  8. Cellular reactions to patterned biointerfaces

    OpenAIRE

    Schulte, Vera Antonie

    2012-01-01

    The subject of this thesis is to study cellular reactions to topographically, mechanically and biochemically tunable polymeric biomaterials. Different aspects of in vitro cell-biomaterial interactions were systematically studied with the murine fibroblast cell line NIH L929 and primary human dermal fibroblasts (HDFs). Besides a general cytocompatibility assessment of the applied materials and the quantification of cell adhesion per se, cell morphological changes (e.g. cell spreading) and intr...

  9. CELLULAR INTERACTIONS MEDIATED BY GLYCONECTIDS

    OpenAIRE

    Popescu, O.; Sumanovski, L. T.; I. Checiu; Elisabeta Popescu; G. N. Misevic

    1999-01-01

    Cellular interactions involve many types of cell surface molecules and operate via homophilic and/or heterophilic protein-protein and protein-carbohydrate binding. Our investigations in different model-systems (marine invertebrates and mammals) have provided direct evidence that a novel class of primordial proteoglycans, named by us gliconectins, can mediate cell adhesion via a new alternative molecular mechanism of polyvalent carbohydrate-carbohydrate binding. Biochemical characterization of...

  10. Progress of cellular dedifferentiation research

    Institute of Scientific and Technical Information of China (English)

    LIU Hu-xian; HU Da-hai; JIA Chi-yu; FU Xiao-bing

    2006-01-01

    Differentiation, the stepwise specialization of cells, and transdifferentiation, the apparent switching of one cell type into another, capture much of the stem cell spotlight. But dedifferentiation, the developmental reversal of a cell before it reinvents itself, is an important process too. In multicellular organisms, cellular dedifferentiation is the major process underlying totipotency, regeneration and formation of new stem cell lineages. In humans,dedifferentiation is often associated with carcinogenesis.The study of cellular dedifferentiation in animals,particularly early events related to cell fate-switch and determination, is limited by the lack of a suitable,convenient experimental system. The classic example of dedifferentiation is limb and tail regeneration in urodele amphibians, such as salamanders. Recently, several investigators have shown that certain mammalian cell types can be induced to dedifferentiate to progenitor cells when stimulated with the appropriate signals or materials. These discoveries open the possibility that researchers might enhance the endogenous regenerative capacity of mammals by inducing cellular dedifferentiation in vivo.

  11. The insect cellular immune response

    Institute of Scientific and Technical Information of China (English)

    Michael R. Strand

    2008-01-01

    The innate immune system of insects is divided into humoral defenses that include the production of soluble effector molecules and cellular defenses like phagocytosis and encapsulation that are mediated by hemocytes. This review summarizes current understanding of the cellular immune response. Insects produce several terminally differentiated types of hemocytes that are distinguished by morphology, molecular and antigenic markers, and function. The differentiated hemocytes that circulate in larval or nymphal stage insects arise from two sources: progenitor cells produced during embryogenesis and mesodermally derived hematopoietic organs. Regulation of hematopoiesis and hemocyte differentiation also involves several different signaling pathways. Phagocytosis and encapsulation require that hemocytes first recognize a given target as foreign followed by activation of downstream signaling and effector responses. A number of humoral and cellular receptors have been identified that recognize different microbes and multicellular parasites. In turn, activation of these receptors stimulates a number of signaling pathways that regulate different hemocyte functions. Recent studies also identify hemocytes as important sources of a number of humoral effector molecules required for killing different foreign invaders.

  12. Cellular communications a comprehensive and practical guide

    CERN Document Server

    Tripathi, Nishith

    2014-01-01

    Even as newer cellular technologies and standards emerge, many of the fundamental principles and the components of the cellular network remain the same. Presenting a simple yet comprehensive view of cellular communications technologies, Cellular Communications provides an end-to-end perspective of cellular operations, ranging from physical layer details to call set-up and from the radio network to the core network. This self-contained source forpractitioners and students represents a comprehensive survey of the fundamentals of cellular communications and the landscape of commercially deployed

  13. Impulsive action and motivation

    NARCIS (Netherlands)

    N.H. Frijda

    2010-01-01

    This paper explores the way in which emotions are causal determinants of action. It argues that emotional events, as appraised by the individual, elicit changes in motive states (called states of action readiness), which in turn may (or may not) cause action. Actions can be elicited automatically, w

  14. Vitamin E Supplementation Delays Cellular Senescence In Vitro.

    Science.gov (United States)

    La Fata, Giorgio; Seifert, Nicole; Weber, Peter; Mohajeri, M Hasan

    2015-01-01

    Vitamin E is an important antioxidant that protects cells from oxidative stress-induced damage, which is an important contributor to the progression of ageing. Ageing can be studied in vitro using primary cells reaching a state of irreversible growth arrest called senescence after a limited number of cellular divisions. Generally, the most utilized biomarker of senescence is represented by the expression of the senescence associated β-galactosidase (SA-β-gal). We aimed here to study the possible effects of vitamin E supplementation in two different human primary cell types (HUVECs and fibroblasts) during the progression of cellular senescence. Utilizing an unbiased automated system, based on the detection of the SA-β-gal, we quantified cellular senescence in vitro and showed that vitamin E supplementation reduced the numbers of senescent cells during progression of ageing. Acute vitamin E supplementation did not affect cellular proliferation, whereas it was decreased after chronic treatment. Mechanistically, we show that vitamin E supplementation acts through downregulation of the expression of the cycline dependent kinase inhibitor P21. The data obtained from this study support the antiageing properties of vitamin E and identify possible mechanisms of action that warrant further investigation. PMID:26613084

  15. Vitamin E Supplementation Delays Cellular Senescence In Vitro

    Directory of Open Access Journals (Sweden)

    Giorgio La Fata

    2015-01-01

    Full Text Available Vitamin E is an important antioxidant that protects cells from oxidative stress-induced damage, which is an important contributor to the progression of ageing. Ageing can be studied in vitro using primary cells reaching a state of irreversible growth arrest called senescence after a limited number of cellular divisions. Generally, the most utilized biomarker of senescence is represented by the expression of the senescence associated β-galactosidase (SA-β-gal. We aimed here to study the possible effects of vitamin E supplementation in two different human primary cell types (HUVECs and fibroblasts during the progression of cellular senescence. Utilizing an unbiased automated system, based on the detection of the SA-β-gal, we quantified cellular senescence in vitro and showed that vitamin E supplementation reduced the numbers of senescent cells during progression of ageing. Acute vitamin E supplementation did not affect cellular proliferation, whereas it was decreased after chronic treatment. Mechanistically, we show that vitamin E supplementation acts through downregulation of the expression of the cycline dependent kinase inhibitor P21. The data obtained from this study support the antiageing properties of vitamin E and identify possible mechanisms of action that warrant further investigation.

  16. Hybrid Action Systems

    DEFF Research Database (Denmark)

    Rönnkö, M.; Ravn, Anders Peter; Sere, K.

    2003-01-01

    In this paper we investigate the use of action systems with differential actions in the specifcation of hybrid systems. As the main contribution we generalize the definition of a differential action, allowing the use of arbitrary relations over model variables and their time-derivatives...... in modelling continuous-time dynamics. The generalized differential action has an intuitively appealing predicate transformer semantics, which we show to be both conjunctive and monotonic. In addition, we show that differential actions blend smoothly with conventional actions in action systems, even under...... parallel composition. Moreover, as the strength of the action system formalism is the support for stepwise development by refinement, we investigate refinement involving a differential action. We show that, due to the predicate transformer semantics, standard action refinement techniques apply also...

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2015-10-15

    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

  18. Conservative surgery and adjuvant radiation therapy in the management of adult soft tissue sarcoma of the extremities: clinical and radiobiological results

    International Nuclear Information System (INIS)

    Purpose: The outcome of adult patients with soft tissue sarcoma of the extremities treated with conservative surgery and adjuvant irradiation was evaluated to (a) determine the appropriate treatment volume and radiation dosage in the postoperative setting, and (b) correlate in vitro radiobiological parameters obtained prior to therapy with clinical outcome. Methods and Materials: Sixty-four consecutive adult patients with soft tissue sarcoma of the extremities (40 lower, 24 upper) who underwent conservative surgery and adjuvant irradiation (7 preoperative, 50 postoperative, 7 perioperative) between 1978 and 1991 were reviewed. The initial radiation field margin surrounding the tumor bed/scar was retrospectively analyzed in all postoperative patients. Initial field margins were < 5 cm in 12 patients, 5-9.9 cm in 32 and ≥ 10 cm in 6. Patients with negative pathological margins were initially treated with traditional postoperative doses (64-66 Gy); however, in later years the postoperative dose was reduced to 60 Gy. Thirteen cell lines were established prior to definite therapy, and radiobiological parameters (multitarget and linear-quadratic) were obtained and correlated with outcome. Results: Postoperative patients treated with an initial field margin of < 5 cm had a 5-year local control of 30.4% vs. 93.2% in patients treated with an initial margin of ≥ 5 cm (p = 0.0003). Five-year local control rates were similar in patients treated with initial field margins of 5-9.9 cm (91.6%) compared with those treated with ≥ 10 cm margins (100%) (p = 0.49). While postoperative patients receiving < 60 Gy had a worse local control than those receiving ≥ 60 Gy (p = 0.08), no difference was seen in local control between patients receiving less than traditional postoperative doses (60-63.9 Gy) (74.4%) vs. those receiving 64-66 Gy (87.0%) (p = 0.5). The local control of patients treated in the later years of the study, with strict attention to surgical and radiotherapeutic

  19. Cellular host responses to gliomas.

    Directory of Open Access Journals (Sweden)

    Joseph Najbauer

    Full Text Available BACKGROUND: Glioblastoma multiforme (GBM is the most aggressive type of malignant primary brain tumors in adults. Molecular and genetic analysis has advanced our understanding of glioma biology, however mapping the cellular composition of the tumor microenvironment is crucial for understanding the pathology of this dreaded brain cancer. In this study we identified major cell populations attracted by glioma using orthotopic rodent models of human glioma xenografts. Marker-specific, anatomical and morphological analyses revealed a robust influx of host cells into the main tumor bed and tumor satellites. METHODOLOGY/PRINCIPAL FINDINGS: Human glioma cell lines and glioma spheroid orthotopic implants were used in rodents. In both models, the xenografts recruited large numbers of host nestin-expressing cells, which formed a 'network' with glioma. The host nestin-expressing cells appeared to originate in the subventricular zone ipsilateral to the tumor, and were clearly distinguishable from pericytes that expressed smooth muscle actin. These distinct cell populations established close physical contact in a 'pair-wise' manner and migrated together to the deeper layers of tumor satellites and gave rise to tumor vasculature. The GBM biopsy xenografts displayed two different phenotypes: (a low-generation tumors (first in vivo passage in rats were highly invasive and non-angiogenic, and host nestin-positive cells that infiltrated into these tumors displayed astrocytic or elongated bipolar morphology; (b high-generation xenografts (fifth passage had pronounced cellularity, were angiogenic with 'glomerulus-like' microvascular proliferations that contained host nestin-positive cells. Stromal cell-derived factor-1 and its receptor CXCR4 were highly expressed in and around glioma xenografts, suggesting their role in glioma progression and invasion. CONCLUSIONS/SIGNIFICANCE: Our data demonstrate a robust migration of nestin-expressing host cells to glioma, which

  20. Estimation in Cellular Radio Systems

    OpenAIRE

    Blom, Jonas; Gunnarsson, Fredrik; Gustafsson, Fredrik

    1999-01-01

    The problem to track time-varying parameters in cellular radio systems is studied, and the focus is on estimation based only on the signals that are readily available. Previous work have demonstrated very good performance, but were relying on analog measurement that are not available. Most of the information is lost due to quantization and sampling at a rate that might be as low as 2 Hz (GSM case). For that matter a maximum likelihood estimator have been designed and exemplified in the case o...

  1. Cellular immune responses to HIV

    Science.gov (United States)

    McMichael, Andrew J.; Rowland-Jones, Sarah L.

    2001-04-01

    The cellular immune response to the human immunodeficiency virus, mediated by T lymphocytes, seems strong but fails to control the infection completely. In most virus infections, T cells either eliminate the virus or suppress it indefinitely as a harmless, persisting infection. But the human immunodeficiency virus undermines this control by infecting key immune cells, thereby impairing the response of both the infected CD4+ T cells and the uninfected CD8+ T cells. The failure of the latter to function efficiently facilitates the escape of virus from immune control and the collapse of the whole immune system.

  2. Cellular automata a parallel model

    CERN Document Server

    Mazoyer, J

    1999-01-01

    Cellular automata can be viewed both as computational models and modelling systems of real processes. This volume emphasises the first aspect. In articles written by leading researchers, sophisticated massive parallel algorithms (firing squad, life, Fischer's primes recognition) are treated. Their computational power and the specific complexity classes they determine are surveyed, while some recent results in relation to chaos from a new dynamic systems point of view are also presented. Audience: This book will be of interest to specialists of theoretical computer science and the parallelism challenge.

  3. Game of Life Cellular Automata

    CERN Document Server

    Adamatzky, Andrew

    2010-01-01

    In the late 1960s, British mathematician John Conway invented a virtual mathematical machine that operates on a two-dimensional array of square cell. Each cell takes two states, live and dead. The cells' states are updated simultaneously and in discrete time. A dead cell comes to life if it has exactly three live neighbours. A live cell remains alive if two or three of its neighbours are alive, otherwise the cell dies. Conway's Game of Life became the most programmed solitary game and the most known cellular automaton. The book brings together results of forty years of study into computational

  4. Protein accounting in the cellular economy

    Science.gov (United States)

    Vázquez-Laslop, Nora; Mankin, Alexander S.

    2014-01-01

    Knowing the copy number of cellular proteins is critical for understanding cell physiology. By being able to measure the absolute synthesis rates of the majority of cellular proteins, Li et al. (2014) gain insights into key aspects of translation regulation and fundamental principles of cellular strategies to adjust protein synthesis according to the needs. PMID:24766801

  5. Inferences about Action Engage Action Systems

    Science.gov (United States)

    Taylor, Lawrence J.; Lev-Ari, Shiri; Zwaan, Rolf A.

    2008-01-01

    Verbal descriptions of actions activate compatible motor responses [Glenberg, A. M., & Kaschak, M. P. (2002). Grounding language in action. "Psychonomic Bulletin & Review, 9", 558-565]. Previous studies have found that the motor processes for manual rotation are engaged in a direction-specific manner when a verb disambiguates the direction of…

  6. Cellular uptake of metallated cobalamins.

    Science.gov (United States)

    Tran, Mai Thanh Quynh; Stürup, Stefan; Lambert, Ian Henry; Gammelgaard, Bente; Furger, Evelyne; Alberto, Roger

    2016-03-01

    Cellular uptake of vitamin B12-cisplatin conjugates was estimated via detection of their metal constituents (Co, Pt, and Re) by inductively coupled plasma mass spectrometry (ICP-MS). Vitamin B12 (cyano-cob(iii)alamin) and aquo-cob(iii)alamin [Cbl-OH2](+), which differ in the β-axial ligands (CN(-) and H2O, respectively), were included as control samples. The results indicated that B12 derivatives delivered cisplatin to both cellular cytosol and nuclei with an efficiency of one third compared to the uptake of free cisplatin cis-[Pt(II)Cl2(NH3)2]. In addition, uptake of charged B12 derivatives including [Cbl-OH2](+), [{Co}-CN-{cis-PtCl(NH3)2}](+), [{Re}-{Co}-CN-{cis-PtCl(NH3)2}](+), and [{Co}-CN-{trans-Pt(Cyt)(NH3)2}](2+) (Cyt = cytarabin) was high compared to neutral B12, which implied the existence of an additional internalization pathway for charged B12 vitamin analogs. The affinities of the charged B12 derivatives to the B12 transporters HC, IF and TC were similar to that of native vitamin B12. PMID:26739575

  7. Cellular Therapy for Heart Failure.

    Science.gov (United States)

    Psaltis, Peter J; Schwarz, Nisha; Toledo-Flores, Deborah; Nicholls, Stephen J

    2016-01-01

    The pathogenesis of cardiomyopathy and heart failure (HF) is underpinned by complex changes at subcellular, cellular and extracellular levels in the ventricular myocardium. For all of the gains that conventional treatments for HF have brought to mortality and morbidity, they do not adequately address the loss of cardiomyocyte numbers in the remodeling ventricle. Originally conceived to address this problem, cellular transplantation for HF has already gone through several stages of evolution over the past two decades. Various cell types and delivery routes have been implemented to positive effect in preclinical models of ischemic and nonischemic cardiomyopathy, with pleiotropic benefits observed in terms of myocardial remodeling, systolic and diastolic performance, perfusion, fibrosis, inflammation, metabolism and electrophysiology. To a large extent, these salubrious effects are now attributed to the indirect, paracrine capacity of transplanted stem cells to facilitate endogenous cardiac repair processes. Promising results have also followed in early phase human studies, although these have been relatively modest and somewhat inconsistent. This review details the preclinical and clinical evidence currently available regarding the use of pluripotent stem cells and adult-derived progenitor cells for cardiomyopathy and HF. It outlines the important lessons that have been learned to this point in time, and balances the promise of this exciting field against the key challenges and questions that still need to be addressed at all levels of research, to ensure that cell therapy realizes its full potential by adding to the armamentarium of HF management. PMID:27280304

  8. Cellular automata modelling of SEIRS

    Institute of Scientific and Technical Information of China (English)

    Liu Quan-Xing; Jin Zhen

    2005-01-01

    In this paper the SEIRS epidemic spread is analysed, and a two-dimensional probability cellular automata model for SEIRS is presented. Each cellular automation cell represents a part of the population that may be found in one of five states of individuals: susceptible, exposed (or latency), infected, immunized (or recovered) and death. Here studied are the effects of two cases on the epidemic spread. i.e. the effects of non-segregation and segregation on the latency and the infected of population. The conclusion is reached that the epidemic will persist in the case of non-segregation but it will decrease in the case of segregation. The proposed model can serve as a basis for the development of algorithms to simulate real epidemics based on real data. Last we find the density series of the exposed and the infected will fluctuate near a positive equilibrium point, when the constant for the immunized is less than its corresponding constant τ0. Our theoretical results are verified by numerical simulations.

  9. Cellular functions of the microprocessor.

    Science.gov (United States)

    Macias, Sara; Cordiner, Ross A; Cáceres, Javier F

    2013-08-01

    The microprocessor is a complex comprising the RNase III enzyme Drosha and the double-stranded RNA-binding protein DGCR8 (DiGeorge syndrome critical region 8 gene) that catalyses the nuclear step of miRNA (microRNA) biogenesis. DGCR8 recognizes the RNA substrate, whereas Drosha functions as an endonuclease. Recent global analyses of microprocessor and Dicer proteins have suggested novel functions for these components independent of their role in miRNA biogenesis. A HITS-CLIP (high-throughput sequencing of RNA isolated by cross-linking immunoprecipitation) experiment designed to identify novel substrates of the microprocessor revealed that this complex binds and regulates a large variety of cellular RNAs. The microprocessor-mediated cleavage of several classes of RNAs not only regulates transcript levels, but also modulates alternative splicing events, independently of miRNA function. Importantly, DGCR8 can also associate with other nucleases, suggesting the existence of alternative DGCR8 complexes that may regulate the fate of a subset of cellular RNAs. The aim of the present review is to provide an overview of the diverse functional roles of the microprocessor.

  10. Universal map for cellular automata

    Energy Technology Data Exchange (ETDEWEB)

    García-Morales, V., E-mail: vmorales@ph.tum.de [Institute for Advanced Study – Technische Universität München, Lichtenbergstr. 2a, D-85748 Garching (Germany)

    2012-08-20

    A universal map is derived for all deterministic 1D cellular automata (CAs) containing no freely adjustable parameters and valid for any alphabet size and any neighborhood range (including non-symmetrical neighborhoods). The map can be extended to an arbitrary number of dimensions and topologies and to arbitrary order in time. Specific CA maps for the famous Conway's Game of Life and Wolfram's 256 elementary CAs are given. An induction method for CAs, based in the universal map, allows mathematical expressions for the orbits of a wide variety of elementary CAs to be systematically derived. -- Highlights: ► A universal map is derived for all deterministic 1D cellular automata (CA). ► The map is generalized to 2D for Von Neumann, Moore and hexagonal neighborhoods. ► A map for all Wolfram's 256 elementary CAs is derived. ► A map for Conway's “Game of Life” is obtained.

  11. Melanoma screening with cellular phones.

    Directory of Open Access Journals (Sweden)

    Cesare Massone

    Full Text Available BACKGROUND: Mobile teledermatology has recently been shown to be suitable for teledermatology despite limitations in image definition in preliminary studies. The unique aspect of mobile teledermatology is that this system represents a filtering or triage system, allowing a sensitive approach for the management of patients with emergent skin diseases. METHODOLOGY/PRINCIPAL FINDINGS: In this study we investigated the feasibility of teleconsultation using a new generation of cellular phones in pigmented skin lesions. 18 patients were selected consecutively in the Pigmented Skin Lesions Clinic of the Department of Dermatology, Medical University of Graz, Graz (Austria. Clinical and dermoscopic images were acquired using a Sony Ericsson with a built-in two-megapixel camera. Two teleconsultants reviewed the images on a specific web application (http://www.dermahandy.net/default.asp where images had been uploaded in JPEG format. Compared to the face-to-face diagnoses, the two teleconsultants obtained a score of correct telediagnoses of 89% and of 91.5% reporting the clinical and dermoscopic images, respectively. CONCLUSIONS/SIGNIFICANCE: The present work is the first study performing mobile teledermoscopy using cellular phones. Mobile teledermatology has the potential to become an easy applicable tool for everyone and a new approach for enhanced self-monitoring for skin cancer screening in the spirit of the eHealth program of the European Commission Information for Society and Media.

  12. All in action

    CERN Document Server

    Annila, Arto

    2010-01-01

    The principle of least action provides a holistic worldview in which nature in its entirety and every detail is pictured in terms of actions. Each and every action is ultimately composed of one or multiples of the most elementary action which corresponds to the Planck's constant. Elements of space are closed actions, known as fermions, whereas elements of time are open actions, known as bosons. The actions span energy landscape, the Universe which evolves irreversibly according to the 2nd law of thermodynamics by diminishing density differences in least time. During the step-by-step evolution densely-curled actions unfold by opening up and expelling one or multiple elementary actions to their surrounding sparser space. The manifold's varieties process from one symmetry group to another until the equivalence to their dual, i.e., the surrounding density has been attained. The scale-free physical portrayal of nature does not recognize any fundamental difference between fundamental particles and fundamental force...

  13. Cellular Response of the Amoeba Acanthamoeba castellanii to Chlorine, Chlorine Dioxide, and Monochloramine Treatments ▿

    OpenAIRE

    Mogoa, Emerancienne; Bodet, Charles; Morel, Franck; Rodier, Marie-Hélène; Legube, Bernard; Héchard, Yann

    2011-01-01

    Acanthamoeba castellanii is a free-living amoebae commonly found in water systems. Free-living amoebae might be pathogenic but are also known to bear phagocytosis-resistant bacteria, protecting these bacteria from water treatments. The mode of action of these treatments is poorly understood, particularly on amoebae. It is important to examine the action of these treatments on amoebae in order to improve them. The cellular response to chlorine, chlorine dioxide, and monochloramine was tested o...

  14. Cellular automata for traffic flow simulation with safety embedded notions

    OpenAIRE

    Larraga, M. E.; Alvarez-Icaza, L.

    2007-01-01

    In this paper a cellular automata model for one-lane traffic flow is presented. A new set of rules is proposed to better capture driver reactions to traffic that are intended to preserve safety on the highway. As a result, drivers behavior is derived from an analysis that determines the most appropriate action for a vehicle based on the distance from the vehicle ahead of it and the velocities of the two neighbor vehicles. The model preserves simplicity of CA rules and at the same time makes t...

  15. 30th and 29th anniversary of reactor accidents in A-1 nuclear power plant Jaslovske Bohunice - radioecological and radiobiological consequences

    International Nuclear Information System (INIS)

    In this paper authors present facts about construction, operation and reactor accidents in A-1 Nuclear Power Plant Jaslovske Bohunice, Slovakia. There was the reactor KS 150 (HWGCR) cooled with carbon dioxide and moderated with heavy water. A-1 NPP was commissioned on December 25, 1972. The first reactor accident happened on January 5, 1976 during fuel loading. Two persons of personal died by suffocation with carbon dioxide. This accident has been not evaluated according to the INES scale up to present time. The second serious accident in A-1 NPP occurred in February 22, 1977 also during fuel loading. This INES level 4 of reactor accident resulted in damaged fuel integrity with extensive corrosion damage of fuel cladding and release of radioactivity into the plant area. The A-1 NPP was consecutively shut down and is being decommissioned in the present time. Both reactor accidents are described in this paper. Some radioecological and radiobiological consequences of accidents and contamination of area of A-1 NPP as well as of Manivier canal and Dudvah River as result of flooding during the decommissioning are presented. (authors)

  16. The world's high background natural radiation areas (HBNRAs) revisited: A broad overview of the dosimetric, epidemiological and radiobiological issues

    International Nuclear Information System (INIS)

    The residents of the world's high background natural radiation areas (HBNRAs), such as Ramsar (in Iran), Guarapari (in Brazil), Orissa and Kerala (in India) and Yangjiang (in China) have lived in these areas for generations under extraordinary radiation fields. The failure of earlier epidemiological studies to report any substantial increase in cancer incidence in HBNRAs has raised some controversy regarding the validity of the linear no-threshold hypothesis. This paper reviews some of the most recent studies of HBNRAs with the intent of stimulating greater research interest in the dosimetric, epidemiological and radiobiological issues related to the world's HBNRAs and proposes solutions to the challenges facing HBNRA studies. This paper may serve as a useful reference for some of the harder-to-find literature. - Highlights: • Some of the challenging issues of HBNRAs have not been resolved. • A literature review of the most recent studies of HBNRAs has been conducted. • An overview of some of the challenging issues and viable solutions are presented

  17. Cellular Delivery of RNA Nanoparticles.

    Science.gov (United States)

    Parlea, Lorena; Puri, Anu; Kasprzak, Wojciech; Bindewald, Eckart; Zakrevsky, Paul; Satterwhite, Emily; Joseph, Kenya; Afonin, Kirill A; Shapiro, Bruce A

    2016-09-12

    RNA nanostructures can be programmed to exhibit defined sizes, shapes and stoichiometries from naturally occurring or de novo designed RNA motifs. These constructs can be used as scaffolds to attach functional moieties, such as ligand binding motifs or gene expression regulators, for nanobiology applications. This review is focused on four areas of importance to RNA nanotechnology: the types of RNAs of particular interest for nanobiology, the assembly of RNA nanoconstructs, the challenges of cellular delivery of RNAs in vivo, and the delivery carriers that aid in the matter. The available strategies for the design of nucleic acid nanostructures, as well as for formulation of their carriers, make RNA nanotechnology an important tool in both basic research and applied biomedical science. PMID:27509068

  18. Discrete geodesics and cellular automata

    CERN Document Server

    Arrighi, Pablo

    2015-01-01

    This paper proposes a dynamical notion of discrete geodesics, understood as straightest trajectories in discretized curved spacetime. The notion is generic, as it is formulated in terms of a general deviation function, but readily specializes to metric spaces such as discretized pseudo-riemannian manifolds. It is effective: an algorithm for computing these geodesics naturally follows, which allows numerical validation---as shown by computing the perihelion shift of a Mercury-like planet. It is consistent, in the continuum limit, with the standard notion of timelike geodesics in a pseudo-riemannian manifold. Whether the algorithm fits within the framework of cellular automata is discussed at length. KEYWORDS: Discrete connection, parallel transport, general relativity, Regge calculus.

  19. Cellular compartmentalization of secondary metabolism

    Directory of Open Access Journals (Sweden)

    H. Corby eKistler

    2015-02-01

    Full Text Available Fungal secondary metabolism is often considered apart from the essential housekeeping functions of the cell. However, there are clear links between fundamental cellular metabolism and the biochemical pathways leading to secondary metabolite synthesis. Besides utilizing key biochemical precursors shared with the most essential processes of the cell (e.g. amino acids, acetyl CoA, NADPH, enzymes for secondary metabolite synthesis are compartmentalized at conserved subcellular sites that position pathway enzymes to use these common biochemical precursors. Co-compartmentalization of secondary metabolism pathway enzymes also may function to channel precursors, promote pathway efficiency and sequester pathway intermediates and products from the rest of the cell. In this review we discuss the compartmentalization of three well-studied fungal secondary metabolite biosynthetic pathways for penicillin G, aflatoxin and deoxynivalenol, and summarize evidence used to infer subcellular localization. We also discuss how these metabolites potentially are trafficked within the cell and may be exported.

  20. Thermomechanical characterisation of cellular rubber

    Science.gov (United States)

    Seibert, H.; Scheffer, T.; Diebels, S.

    2016-09-01

    This contribution discusses an experimental possibility to characterise a cellular rubber in terms of the influence of multiaxiality, rate dependency under environmental temperature and its behaviour under hydrostatic pressure. In this context, a mixed open and closed cell rubber based on an ethylene propylene diene monomer is investigated exemplarily. The present article intends to give a general idea of the characterisation method and the considerable effects of this special type of material. The main focus lies on the experimental procedure and the used testing devices in combination with the analysis methods such as true three-dimensional digital image correlation. The structural compressibility is taken into account by an approach for a material model using the Theory of Porous Media with additional temperature dependence.

  1. Novel Materials for Cellular Nanosensors

    DEFF Research Database (Denmark)

    Sasso, Luigi

    modifications for electrochemical nanosensors for the detection of analytes released from cells. Two type of materials were investigated, each pertaining to the two different aspects of such devices: peptide nanostructures were studied for the creation of cellular sensing substrates that mimic in vivo surfaces......' functionalization with biomolecules, metal nanoparticles and chemical functional groups such as thiols, showing the versatility and flexibility of this material's applications. A technique for the patterning of these nanostructures using soft lithography was also developed and tested for suitable cell sensing....... An in vivo investigation also gave evidence of how the peptide nanowires can be used as surface modification in implantable electrodes for neurological measurements. Conducting polymers were utilized in electrode modifications for electrochemical sensor surfaces. Both chemical and electrochemical deposition...

  2. An Asynchronous Cellular Automata-Based Adaptive Illumination Facility

    Science.gov (United States)

    Bandini, Stefania; Bonomi, Andrea; Vizzari, Giuseppe; Acconci, Vito

    The term Ambient Intelligence refers to electronic environments that are sensitive and responsive to the presence of people; in the described scenario the environment itself is endowed with a set of sensors (to perceive humans or other physical entities such as dogs, bicycles, etc.), interacting with a set of actuators (lights) that choose their actions (i.e. state of illumination) in an attempt improve the overall experience of these users. The model for the interaction and action of sensors and actuators is an asynchronous Cellular Automata (CA) with memory, supporting a self-organization of the system as a response to the presence and movements of people inside it. The paper will introduce the model, as well as an ad hoc user interface for the specification of the relevant parameters of the CA transition rule that determines the overall system behaviour.

  3. CHRONIC IRRADIATION OF SCOTS PINE TREES (PINUS SYLVESTRIS) IN THE CHERNOBYL EXCLUSION ZONE: DOSIMETRY AND RADIOBIOLOGICAL EFFECTS

    Energy Technology Data Exchange (ETDEWEB)

    Farfan, E.; Jannik, T.

    2011-10-01

    To identify effects of chronic internal and external radiation exposure for components of terrestrial ecosystems, a comprehensive study of Scots pine trees in the Chernobyl Exclusion Zone was performed. The experimental plan included over 1,100 young trees (up to 20 years old) selected from areas with varying levels of radioactive contamination. These pine trees were planted after the 1986 Chernobyl Nuclear Power Plant accident mainly to prevent radionuclide resuspension and soil erosion. For each tree, the major morphological parameters and radioactive contamination values were identified. Cytological analyses were performed for selected trees representing all dose rate ranges. A specially developed dosimetric model capable of taking into account radiation from the incorporated radionuclides in the trees was developed for the apical meristem. The calculated dose rates for the trees in the study varied within three orders of magnitude, from close to background values in the control area (about 5 mGy y{sup -1}) to approximately 7 Gy y{sup -1} in the Red Forest area located in the immediate vicinity of the Chernobyl Nuclear Power Plant site. Dose rate/effect relationships for morphological changes and cytogenetic defects were identified and correlations for radiation effects occurring on the morphological and cellular level were established.

  4. Recovery Action Mapping Tool

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Recovery Action Mapping Tool is a web map that allows users to visually interact with and query actions that were developed to recover species listed under the...

  5. Action Rules Mining

    CERN Document Server

    Dardzinska, Agnieszka

    2013-01-01

    We are surrounded by data, numerical, categorical and otherwise, which must to be analyzed and processed to convert it into information that instructs, answers or aids understanding and decision making. Data analysts in many disciplines such as business, education or medicine, are frequently asked to analyze new data sets which are often composed of numerous tables possessing different properties. They try to find completely new correlations between attributes and show new possibilities for users.   Action rules mining discusses some of data mining and knowledge discovery principles and then describe representative concepts, methods and algorithms connected with action. The author introduces the formal definition of action rule, notion of a simple association action rule and a representative action rule, the cost of association action rule, and gives a strategy how to construct simple association action rules of a lowest cost. A new approach for generating action rules from datasets with numerical attributes...

  6. 乳酸对心肌收缩力和细胞动作电位的影响与运动能力的相关性%The Effect of Lactate on the Contractile Force of Ventricular Papillary Muscle and Cellular Action Potential

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective To study the effect of lactate of differentconcentration on the action potential of ventricular papillary muscle cell (n=4) and contractile force (n=10).Method Using intracellular microelectrode technique and microtension depicting method.Result The Result showed the effect of lactated solution of a certain comcentration became obvious. After perfused with lactate solution of 4mmol/L,the vilocity maximum decreased significantly (p<0.05) showed the 4mmol/L lactate solution decreased the rate of depolarization: decreased the efficency of Na + channel; lactate solution decreased the contractile force of cardiac muscle. Conclusion The possible mechanism was: Ca+ influx and Na+ - H+ exchange were inhibited, resulted in the elevation of intracellular H+ concentration; through Na+-Ca2+ exchange, Ca2+ efflux decreased resulted in the intracellular Ca2+ decreased resulted in the intracellular Ca2+ overload.

  7. Conservation Action Handbook.

    Science.gov (United States)

    National Rifle Association, Washington, DC.

    Conservation problems are identified, with some suggestions for action. General areas covered are: Wildlife Conservation, Soil Conservation, Clean Water, Air Pollution Action, and Outdoor Recreation Action. Appendices list private organizations or agencies concerned with natural resource use and/or management, congressional committees considering…

  8. Putting Action in Perspective

    Science.gov (United States)

    Lozano, Sandra C.; Hard, Bridgette Martin; Tversky, Barbara

    2007-01-01

    Embodied approaches to cognition propose that our own actions influence our understanding of the world. Do other people's actions also have this influence? The present studies show that perceiving another person's actions changes the way people think about objects in a scene. In Study 1, participants viewed a photograph and answered a question…

  9. Controlling Cellular Endocytosis at the Nanoscale

    Science.gov (United States)

    Battaglia, Giuseppe

    2011-03-01

    One of the most challenging aspects of drug delivery is the intra-cellular delivery of active agents. Several drugs and especially nucleic acids all need to be delivered within the cell interior to exert their therapeutic action. Small hydrophobic molecules can permeate cell membranes with relative ease, but hydrophilic molecules and especially large macromolecules such as proteins and nucleic acids require a vector to assist their transport across the cell membrane. This must be designed so as to ensure intracellular delivery without compromising cell viability. We have recently achieved this by using pH-sensitive poly(2-(methacryloyloxy)ethyl-phosphorylcholine)- co -poly(2-(diisopropylamino)ethyl methacrylate) (PMPC-PDPA) and poly(ethylene oxide)-co- poly(2-(diisopropylamino)ethyl methacrylate) (PEO-PDPA) diblock copolymers that self-assemble to form vesicles in aqueous solution. These vesicles combine a non-fouling PMPC or PEO block with a pH-sensitive PDPA block and have the ability to encapsulate both hydrophobic molecules within the vesicular membrane and hydrophilic molecules within their aqueous cores. The pH sensitive nature of the PDPA blocks make the diblock copolymers forming stable vesicles at physiological pH but that rapid dissociation of these vesicles occurs between pH 5 and pH 6 to form molecularly dissolved copolymer chains (unimers). We used these vesicles to encapsulate small and large macromolecules and these were successfully delivered intracellularly including nucleic acid, drugs, quantum dots, and antibodies. Dynamic light scattering, zeta potential measurements, and transmission electron microscopy were used to study and optimise the encapsulation processes. Confocal laser scanning microscopy, fluorescence flow cytometry and lysates analysis were used to quantify cellular uptake and to study the kinetics of this process in vitro and in vivo. We show the effective cytosolic delivery of nucleic acids, proteins, hydrophobic molecules

  10. 76 FR 82179 - Drivers of CMVs: Restricting the Use of Cellular Phones

    Science.gov (United States)

    2011-12-30

    ... Cellular Phones AGENCY: Federal Motor Carrier Safety Administration (FMCSA), DOT. ACTION: Final rule..., 2011 (76 FR 75470), which restricted the use of ] hand-held mobile telephones by drivers of commercial... . SUPPLEMENTARY INFORMATION: For FMCSA and PHMSA's Final Rule published on December 2, 2011 (76 FR 75470),...

  11. Toxic action/toxicity.

    Science.gov (United States)

    Hathway, D E

    2000-02-01

    ,Z-muconaldehyde forms cyclic products containing a pyrrole residue linked to purine. Increased HbCO concentrations reduce the O2-carrying capacity of the blood, and the changed shape of the O2-Hb dissociation curve parallels disturbance in O2 unloading. CN- acts on electron transport and paralyses respiration. In telodrin poisoning, preconvulsive glutamine formation abstracts tricarboxylic acid intermediates incommensurately with normal cerebral respiration. Antigen-antibody complexing depletes the antibody titre, available against infection. At high doses of Cd, Cd-thionein filtered through the kidneys is reabsorbed and tubular lesions produced. Some organophosphate insecticides promote irreversible acetylcholinesterase phosphorylation and blockade nerve function, and others react with neurotoxic esterase to cause delayed neuropathy. The evidence for Paraquat pulmonary poisoning suggests a radical mechanism involving three interrelated cyclic reaction stages. The action of N- and O8 (O substituent in 6-position of the purine) demethylases explains deletion mechanisms for DNA-alkyl adducts. DNA-directed synthesis in the presence of ultimate carcinogens provides for an estimation of misincorporations, which implicate the same transversions as those found by direct mutagenicity testing. Chemical carcinogens recognize tissue-sensitive cells and modify their heritable genetic complement. Oncoproteins encoded by activated oncogenes signal the transformation of normal cells into cancer cells. The importance of the H-ras oncogene and p53 tumour-suppressor gene is stressed. Antidotal action is analysed; for example, parenteral glutamine administration to telodrin-intoxicated rats restores the depleted cerebral glutamate level and prevents seizures. Glutamate acts as anticonvulsant in petit mal epilepsy. In general, therefore, the reaction of the toxicant-related substance with the relevant target-tissue macromolecule accounts for the biochemical/biological events at a cellular level a PMID

  12. Cellular response to modulated radiation fields

    Science.gov (United States)

    Claridge Mackonis, E.; Suchowerska, N.; Zhang, M.; Ebert, M.; McKenzie, D. R.; Jackson, M.

    2007-09-01

    Cell survival following exposure to spatially modulated beams, as created by intensity-modulated radiotherapy (IMRT), is investigated. In vitro experiments were performed using malignant melanoma cells (MM576) exposed to a therapeutic megavoltage photon beam. We compared cell survival in modulated fields with cell survival in uniform control fields. Three different spatial modulations of the field were used: a control 'uniform' field in which all cells in a flask were uniformly exposed; a 'quarter' field in which 25% of cells at one end of the flask were exposed and a 'striped' field in which 25% of cells were exposed in three parallel stripes. The cell survival in both the shielded and unshielded regions of the modulated fields, as determined by a clonogenic assay, were compared to the cell survival in the uniform field. We have distinguished three ways in which cell survival is influenced by the fate of neighbouring cells. The first of these (type I effect) is the previously reported classical Bystander effect, where cell survival is reduced when communicating with irradiated cells. We find two new types of Bystander effect. The type II effect is an observed increase in cell survival when nearby cells receive a lethal dose. The type III effect is an increase in the survival of cells receiving a high dose of radiation, when nearby cells receive a low dose. These observations of the Bystander effects emphasize the need for improved radiobiological models, which include communicated effects and account for the effects of modulated dose distribution.

  13. Oxysterols and Their Cellular Effectors

    Directory of Open Access Journals (Sweden)

    Eija Nissilä

    2012-02-01

    Full Text Available Oxysterols are oxidized 27-carbon cholesterol derivatives or by-products of cholesterol biosynthesis, with a spectrum of biologic activities. Several oxysterols have cytotoxic and pro-apoptotic activities, the ability to interfere with the lateral domain organization, and packing of membrane lipids. These properties may account for their suggested roles in the pathology of diseases such as atherosclerosis, age-onset macular degeneration and Alzheimer’s disease. Oxysterols also have the capacity to induce inflammatory responses and play roles in cell differentiation processes. The functions of oxysterols as intermediates in the synthesis of bile acids and steroid hormones, and as readily transportable forms of sterol, are well established. Furthermore, their actions as endogenous regulators of gene expression in lipid metabolism via liver X receptors and the Insig (insulin-induced gene proteins have been investigated in detail. The cytoplasmic oxysterol-binding protein (OSBP homologues form a group of oxysterol/cholesterol sensors that has recently attracted a lot of attention. However, their mode of action is, as yet, poorly understood. Retinoic acid receptor-related orphan receptors (ROR α and γ, and Epstein-Barr virus induced gene 2 (EBI2 have been identified as novel oxysterol receptors, revealing new physiologic oxysterol effector mechanisms in development, metabolism, and immunity, and evoking enhanced interest in these compounds in the field of biomedicine.

  14. Differential Equations as Actions

    DEFF Research Database (Denmark)

    Ronkko, Mauno; Ravn, Anders P.

    1997-01-01

    We extend a conventional action system with a primitive action consisting of a differential equation and an evolution invariant. The semantics is given by a predicate transformer. The weakest liberal precondition is chosen, because it is not always desirable that steps corresponding to differential...... actions shall terminate. It is shown that the proposed differential action has a semantics which corresponds to a discrete approximation when the discrete step size goes to zero. The extension gives action systems the power to model real-time clocks and continuous evolutions within hybrid systems....

  15. Action research: Scandinavian Experiences

    DEFF Research Database (Denmark)

    Rasmussen, Lauge Baungaard

    2004-01-01

    The article focus on paradigms, methods and ethics of action research in the Scandinavian countries. The special features of the action research paradigm is identified. A historical overview follows of some main action research projects in Norway, Sweden and Denmark. The tendency towards upsclae...... action research projects from organisational or small community projects yo large-scale, regional based network apporaches are also outlined and discussed. Finally, a synthesised approach of the classical, socio-technical action research approach and the large-scale network and holistic approaches is...

  16. Cellular phones: are they detrimental?

    Science.gov (United States)

    Salama, Osama E; Abou El Naga, Randa M

    2004-01-01

    The issue of possible health effects of cellular phones is very much alive in the public's mind where the rapid increase in the number of the users of cell phones in the last decade has increased the exposure of people to the electromagnetic fields (EMFs). Health consequences of long term use of mobile phones are not known in detail but available data indicates the development of non specific annoying symptoms on acute exposure to mobile phone radiations. In an attempt to determine the prevalence of such cell phones associated health manifestations and the factors affecting their occurrence, a cross sectional study was conducted in five randomly selected faculties of Alexandria University. Where, 300 individuals including teaching staff, students and literate employee were equally allocated and randomly selected among the five faculties. Data about mobile phone's users and their medical history, their pattern of mobile usage and the possible deleterious health manifestations associated with cellular phone use was collected. The results revealed 68% prevalence of mobile phone usage, nearly three quarters of them (72.5%) were complainers of the health manifestations. They suffered from headache (43%), earache (38.3%), sense of fatigue (31.6%), sleep disturbance (29.5%), concentration difficulty (28.5%) and face burning sensation (19.2%). Both univariate and multivariate analysis were consistent in their findings. Symptomatic users were found to have significantly higher frequency of calls/day, longer call duration and longer total duration of mobile phone usage/day than non symptomatic users. For headache both call duration and frequency of calls/day were the significant predicting factors for its occurrence (chi2 = 18.208, p = 0.0001). For earache, in addition to call duration, the longer period of owning the mobile phone were significant predictors (chi2 = 16.996, p = 0.0002). Sense of fatigue was significantly affected by both call duration and age of the user

  17. Radiation, nitric oxide and cellular death

    International Nuclear Information System (INIS)

    The mechanisms of radiation induced cellular death constitute an objective of research ever since the first biological effects of radiation were first observed. The explosion of information produced in the last 20 years calls for a careful analysis due to the apparent contradictory data related to the cellular system studied and the range of doses used. This review focuses on the role of the active oxygen species, in particular the nitric oxides, in its relevance as potential mediator of radiation induced cellular death

  18. Autophagy and mitophagy in cellular damage control

    Directory of Open Access Journals (Sweden)

    Jianhua Zhang

    2013-01-01

    Full Text Available Autophagy and mitophagy are important cellular processes that are responsible for breaking down cellular contents, preserving energy and safeguarding against accumulation of damaged and aggregated biomolecules. This graphic review gives a broad summary of autophagy and discusses examples where autophagy is important in controlling protein degradation. In addition we highlight how autophagy and mitophagy are involved in the cellular responses to reactive species and mitochondrial dysfunction. The key signaling pathways for mitophagy are described in the context of bioenergetic dysfunction.

  19. Optimized Cellular Core for Rotorcraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Patz Materials and Technologies proposes to develop a unique structural cellular core material to improve mechanical performance, reduce platform weight and lower...

  20. Efficiency of cellular information processing

    CERN Document Server

    Barato, Andre C; Seifert, Udo

    2014-01-01

    We show that a rate of conditional Shannon entropy reduction, characterizing the learning of an internal process about an external process, is bounded by the thermodynamic entropy production. This approach allows for the definition of an informational efficiency that can be used to study cellular information processing. We analyze three models of increasing complexity inspired by the E. coli sensory network, where the external process is an external ligand concentration jumping between two values. We start with a simple model for which ATP must be consumed so that a protein inside the cell can learn about the external concentration. With a second model for a single receptor we show that the rate at which the receptor learns about the external environment can be nonzero even without any dissipation inside the cell since chemical work done by the external process compensates for this learning rate. The third model is more complete, also containing adaptation. For this model we show inter alia that a bacterium i...

  1. Structure of physics and the chemical or biological action of ionizing radiations - rarely employed ideas

    International Nuclear Information System (INIS)

    The fact is pointed out that phenomena in radiochemistry and micro-scale radiobiology are non-linear similarly to phenomena in modern theoretical physics. A comparison is made of the conceptual development of theoretical physics and of theoretical radiation biology. The use of Bose-Einstein's exciton condensation is suggested for expressing the non-linearity of radiochemical and radiobiological processes. (Ha)

  2. All in Action

    Directory of Open Access Journals (Sweden)

    Arto Annila

    2010-11-01

    Full Text Available The principle of least action provides a holistic worldview in which Nature in its entirety and every detail is described in terms of actions. Each and every action is ultimately composed of one or multiple of the most elementary actions which relates to Planck’s constant. Elements of space are closed actions, known as fermions, whereas elements of time are open actions, known as bosons. The actions span an energy landscape, the Universe, which evolves irreversibly according to the 2nd law of thermodynamics by diminishing energy density differences in least time. During evolution densely-curled actions unfold step-by-step when opening up and expelling one or multiple elementary actions to their surrounding sparser space. The energy landscape will process from one symmetry group to another until the equivalence to its dual, i.e., the surrounding density has been attained. The scale-free physical portrayal of nature in terms of actions does not recognize any fundamental difference between fundamental particles and fundamental forces. Instead a plethora of particles and a diaspora of forces are perceived merely as diverse manifestations of a natural selection for various mechanisms and ways to decrease free energy in the least time.

  3. Accidental tritium release from nuclear technologies and a radiobiological survey of the impact of low dose tritium on the developing mouse brain

    International Nuclear Information System (INIS)

    Full text: The Atomic Energy Act, 1962 provides for the development of the peaceful uses of atomic energy for the welfare of the people in India. The licensing policy adopted for nuclear power stations in India requires that the plants meet stringent requirements based on the system of dose limitation, recommended by the International Commission of Radiological Protection (ICRP). Currently, nuclear energy is contributing just 3% of the country's power generation. The share of nuclear power is proposed to be increased to 10% in the near future. With the introduction of nuclear energy, the need to assess the radioecological and radiobiological impact of radionuclides of long half- life existing in the environment for longer duration has appeared. Tritium, a radioactive by-product of power reactors is one of such major radionuclides of concern. In the world, routine releases and accidental spills of tritium from nuclear power plants pose a growing health and safety concern. Tritium has been observed in ground water in the vicinity of several nuclear stations. Exposure to tritium has been clinically proven to cause deleterious and detectable effects such as teratogenesis, cancer and life shortening in laboratory animals. There is, now, a growing emphasis on tritium in radiation protection as the challenge of nuclear fusion comes nearer. Present investigation is an attempt to elucidate the effects of low dose tritiated water exposure on developing mouse cerebellum. Pregnant Swiss albino mice (12-15 in number were given a priming injection 7.4 and 74 kBq/ml of body water) of tritiated water (HTO) on 16th day of gestation. From the same day onward, through parturition, till the last interval studied, the pregnant females were continuously maintained respectively on 11.1 and 111 kBq/ml of tritiated drinking water provided ad libidum. After cervical dislocation the litters were autopsied on 1, 3, 5 and 6 weeks post- partum. Brains were fixed and then cerebellum from each of

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

    Directory of Open Access Journals (Sweden)

    Wust Peter

    2010-05-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-06-01

    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

  6. Revising the Radiobiological Model of Synchronous Chemotherapy in Head-and-Neck Cancer: A New Analysis Examining Reduced Weighting of Accelerated Repopulation

    International Nuclear Information System (INIS)

    Purpose: Previous studies of synchronous chemoradiation therapy have modeled the additional effect of chemotherapy as additional radiation therapy biologically effective dose (BED). Recent trials of accelerated versus conventional fractionation chemoradiation have cast doubt on such modeling. The purpose of this study was to identify alternative models. Methods and Materials: Nine trials of platinum-based chemoradiation were identified. In radiation therapy-alone arms, the radiation therapy BED for tumor was calculated using standard parameters. In chemoradiation arms, 3 methods were used to calculate tumor BED (tBED): additional BED, addition of 9.3 Gy BED for tumor to the radiation therapy BED; zero repopulation, BED with no correction for repopulation; variable tp (the average doubling time during accelerated repopulation), values of tp 3-10 were used to examine a partial suppression of repopulation. The correlations between the calculated percentage change in tBED for each method and observed percentage change in local control were assessed using the Pearson product moment correlation. Results: Significant correlations were obtained for all 3 methods but were stronger with zero repopulation (P=.0002) and variable tp (tp = 10) (P=.0005) than additional BED (P=.02). Conclusions: Radiobiological models using modified parameters for accelerated repopulation seem to correlate strongly with outcome in chemoradiation studies. The variable tp method shows strong correlation for outcome in local control and is potentially a more suitable model in the chemoradiation setting. However, a lack of trials with an overall treatment time of more than 46 days inhibits further differentiation of the optimal model

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

    Directory of Open Access Journals (Sweden)

    Zhu Guo-Pei

    2011-01-01

    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.

  8. The effect of ionizing radiation with different ionizing density on the uni-cellular Alga Micrasterias denticulate Breb

    International Nuclear Information System (INIS)

    The uni-cellular green alga Micrasterias denticulata Breb is very suitable for cytological, ultrastructural investigations as well as for growth studies of cell populations because of its size and its specific cellular pattern. Therefore these cells were investigated for their cell-cycle-dependent reaction to different types of radiation, dose-rates and cumulated doses and compared with results from the literature on radiobiological effects on single cells. Different types of ionizing radiation were used such as gamma rays (60Co, 241Am), alpha rays (241Am) neutrons (252Cf and 14 MeV-neutrons from a particle-accelerator) and protons (20-MeV-protons from a particle-accelerator). Irradiation with low doses (gamma-, neutron irradiation) did not show any statistically significant results. No effects could be observed after alpha irradiation because of the alpha particles could not penetrate the mucus cover. Irradiation with gamma rays and protons showed statistically significant reversible and irreversible effects. The reversible effect appeared in a dose-dependent division-delay of the populations. The results from literature, cell-cycle observations and ultra-structural investigations point to a block in the G2-phase and prolongation of the S-phase. Irreversible irradiation damage is caused by neutron- and proton irradiation. In the first case the length of division delay shows no dose-dependence. In the second case the following cell-cycles are retarded. The dose-effect-curves of proton-irradiations with different dose-rates show a plateau at high doses, which seems to be effected by the turn-on of an additional repair-mechanism. (Author)

  9. Pulsed feedback defers cellular differentiation.

    Directory of Open Access Journals (Sweden)

    Joe H Levine

    2012-01-01

    Full Text Available Environmental signals induce diverse cellular differentiation programs. In certain systems, cells defer differentiation for extended time periods after the signal appears, proliferating through multiple rounds of cell division before committing to a new fate. How can cells set a deferral time much longer than the cell cycle? Here we study Bacillus subtilis cells that respond to sudden nutrient limitation with multiple rounds of growth and division before differentiating into spores. A well-characterized genetic circuit controls the concentration and phosphorylation of the master regulator Spo0A, which rises to a critical concentration to initiate sporulation. However, it remains unclear how this circuit enables cells to defer sporulation for multiple cell cycles. Using quantitative time-lapse fluorescence microscopy of Spo0A dynamics in individual cells, we observed pulses of Spo0A phosphorylation at a characteristic cell cycle phase. Pulse amplitudes grew systematically and cell-autonomously over multiple cell cycles leading up to sporulation. This pulse growth required a key positive feedback loop involving the sporulation kinases, without which the deferral of sporulation became ultrasensitive to kinase expression. Thus, deferral is controlled by a pulsed positive feedback loop in which kinase expression is activated by pulses of Spo0A phosphorylation. This pulsed positive feedback architecture provides a more robust mechanism for setting deferral times than constitutive kinase expression. Finally, using mathematical modeling, we show how pulsing and time delays together enable "polyphasic" positive feedback, in which different parts of a feedback loop are active at different times. Polyphasic feedback can enable more accurate tuning of long deferral times. Together, these results suggest that Bacillus subtilis uses a pulsed positive feedback loop to implement a "timer" that operates over timescales much longer than a cell cycle.

  10. Cellular injury evidenced by impedance technology and infrared microspectroscopy

    Science.gov (United States)

    le Roux, K.; Prinsloo, L. C.; Meyer, D.

    2015-03-01

    Fourier Transform Infrared (FTIR) spectroscopy is finding increasing biological application, for example in the analysis of diseased tissues and cells, cell cycle studies and investigating the mechanisms of action of anticancer drugs. Cancer treatment studies routinely define the types of cell-drug responses as either total cell destruction by the drug (all cells die), moderate damage (cell deterioration where some cells survive) or reversible cell cycle arrest (cytostasis). In this study the loss of viability and related chemical stress experienced by cells treated with the medicinal plant, Plectranthus ciliatus, was investigated using real time cell electronic sensing (RT-CES) technology and FTIR microspectroscopy. The use of plants as medicines is well established and ethnobotany has proven that crude extracts can serve as treatments against various ailments. The aim of this study was to determine whether FTIR microspectroscopy would successfully distinguish between different types of cellular injury induced by a potentially anticancerous plant extract. Cervical adenocarcinoma (HeLa) cells were treated with a crude extract of Pciliatus and cells monitored using RT-CES to characterize the type of cellular responses induced. Cell populations were then investigated using FTIR microspectroscopy and statistically analysed using One-way Analysis of Variance (ANOVA) and Principal Component Analysis (PCA). The plant extract and a cancer drug control (actinomycin D) induced concentration dependent cellular responses ranging from nontoxic, cytostatic or cytotoxic. Thirteen spectral peaks (915 cm-1, 933 cm-1, 989 cm-1, 1192 cm-1, 1369 cm-1, 1437 cm-1, 1450 cm-1, 1546 cm-1, 1634 cm-1, 1679 cm-1 1772 cm-1, 2874 cm-1 and 2962 cm-1) associated with cytotoxicity were significantly (p value FTIR microspectroscopy confirmed that cytostatic cells were viable and could still recover while also describing early cellular stress related responses on a molecular level.

  11. From Cnn Dynamics to Cellular Wave Computers

    Science.gov (United States)

    Roska, Tamas

    2013-01-01

    Embedded in a historical overview, the development of the Cellular Wave Computing paradigm is presented, starting from the standard CNN dynamics. The theoretical aspects, the physical implementation, the innovation process, as well as the biological relevance are discussed in details. Finally, the latest developments, the physical versus virtual cellular machines, as well as some open questions are presented.

  12. Cellular encoding for interactive evolutionary robotics

    NARCIS (Netherlands)

    Gruau, F.C.; Quatramaran, K.

    1996-01-01

    This work reports experiments in interactive evolutionary robotics. The goal is to evolve an Artificial Neural Network (ANN) to control the locomotion of an 8-legged robot. The ANNs are encoded using a cellular developmental process called cellular encoding. In a previous work similar experiments ha

  13. Recent development of cellular manufacturing systems

    Indian Academy of Sciences (India)

    P K Arora; A Haleem; M K Singh

    2013-06-01

    Cellular manufacturing system has been proved a vital approach for batch and job shop production systems. Group technology has been an essential tool for developing a cellular manufacturing system. The paper aims to discuss various cell formation techniques and highlights the significant research work done in past over the years and attempts to points out the gap in research.

  14. Action in Introductory Physics

    CERN Document Server

    McGinness, Lachlan P

    2015-01-01

    We have investigated the teaching and learning of the stationary action formulation of classical physics in a first-year university class. Instruction proceeded from the many-paths approach to quantum physics through to ray optics, classical mechanics, and relativity. Student learning and misconceptions were studied with quantitative and qualitative techniques. In particular, an action concept inventory was developed through a process of expert consultation and student feedback. Students reported action physics to be accessible, interesting and valuable.

  15. CHAOTIC GROUP ACTIONS

    Institute of Scientific and Technical Information of China (English)

    ShiEnhui; ZhouLizhen; ZhouYoucheng

    2003-01-01

    It is proved that there is no chaotic group actions on any topological space with free arc.In this paper the chaotic actions of the group like G×F,where F is a finite group,are studied.In particular,under a suitable assumption ,if F is a cyclic group,then the topological space which admits a chaotic action of Z×F must admit a chatotic homeomorphism.A topological space which admits a chaotic group action but admits no chaotic horneomorphism is constructed.

  16. Mathematics in Action

    DEFF Research Database (Denmark)

    December 2004-November 2007 Denmark, Hungary, Lithuania, the Netherlands, Norway, Slovenia and Spain have cooperated in the project Mathematics in Action (MiA). The MiA project is supported by the Grundtvig action in the Socrates program of the European Commission. The aim of the project is to su......December 2004-November 2007 Denmark, Hungary, Lithuania, the Netherlands, Norway, Slovenia and Spain have cooperated in the project Mathematics in Action (MiA). The MiA project is supported by the Grundtvig action in the Socrates program of the European Commission. The aim of the project...

  17. Zeta Spectral Action

    CERN Document Server

    Kurkov, Maxim A; Sakellariadou, Mairi; Watcharangkool, Apimook

    2014-01-01

    In this paper we propose a novel definition of the bosonic spectral action using zeta function regularization, in order to address the issues of renormalizability, ultraviolet completeness and spectral dimensions. We compare the zeta spectral action with the usual (cutoff based) spectral action and discuss its purely spectral origin, predictive power, stressing the importance of the issue of the three dimensionful fundamental constants, namely the cosmological constant, the Higgs vacuum expectation value, and the gravitational constant. We emphasize the fundamental role of the neutrino Majorana mass term for the structure of the bosonic action.

  18. Stereoscopically Observing Manipulative Actions.

    Science.gov (United States)

    Ferri, S; Pauwels, K; Rizzolatti, G; Orban, G A

    2016-08-01

    The purpose of this study was to investigate the contribution of stereopsis to the processing of observed manipulative actions. To this end, we first combined the factors "stimulus type" (action, static control, and dynamic control), "stereopsis" (present, absent) and "viewpoint" (frontal, lateral) into a single design. Four sites in premotor, retro-insular (2) and parietal cortex operated specifically when actions were viewed stereoscopically and frontally. A second experiment clarified that the stereo-action-specific regions were driven by actions moving out of the frontoparallel plane, an effect amplified by frontal viewing in premotor cortex. Analysis of single voxels and their discriminatory power showed that the representation of action in the stereo-action-specific areas was more accurate when stereopsis was active. Further analyses showed that the 4 stereo-action-specific sites form a closed network converging onto the premotor node, which connects to parietal and occipitotemporal regions outside the network. Several of the specific sites are known to process vestibular signals, suggesting that the network combines observed actions in peripersonal space with gravitational signals. These findings have wider implications for the function of premotor cortex and the role of stereopsis in human behavior. PMID:27252350

  19. The Universe as a Cellular System

    CERN Document Server

    Aragón-Calvo, Miguel A

    2014-01-01

    Cellular systems are observed everywhere in nature, from crystal domains in metals, soap froth and cucumber cells to the network of cosmological voids. Surprisingly, despite their disparate scale and origin all cellular systems follow certain scaling laws relating their geometry, topology and dynamics. Using a cosmological N-body simulation we found that the Cosmic Web, the largest known cellular system, follows the same scaling relations seen elsewhere in nature. Our results extend the validity of scaling relations in cellular systems by over 30 orders of magnitude in scale with respect to previous studies. The dynamics of cellular systems can be used to interpret local observations such as the local velocity anomaly as the result of a collapsing void in our cosmic backyard. Moreover, scaling relations depend on the curvature of space, providing an independent measure of geometry.

  20. Androgen receptor drives cellular senescence.

    Directory of Open Access Journals (Sweden)

    Yelena Mirochnik

    Full Text Available The accepted androgen receptor (AR role is to promote proliferation and survival of prostate epithelium and thus prostate cancer progression. While growth-inhibitory, tumor-suppressive AR effects have also been documented, the underlying mechanisms are poorly understood. Here, we for the first time link AR anti-cancer action with cell senescence in vitro and in vivo. First, AR-driven senescence was p53-independent. Instead, AR induced p21, which subsequently reduced ΔN isoform of p63. Second, AR activation increased reactive oxygen species (ROS and thereby suppressed Rb phosphorylation. Both pathways were critical for senescence as was proven by p21 and Rb knock-down and by quenching ROS with N-Acetyl cysteine and p63 silencing also mimicked AR-induced senescence. The two pathways engaged in a cross-talk, likely via PML tumor suppressor, whose localization to senescence-associated chromatin foci was increased by AR activation. All these pathways contributed to growth arrest, which resolved in senescence due to concomitant lack of p53 and high mTOR activity. This is the first demonstration of senescence response caused by a nuclear hormone receptor.

  1. The Non-Genomic Actions of Vitamin D

    Directory of Open Access Journals (Sweden)

    Charles S Hii

    2016-03-01

    Full Text Available Since its discovery in 1920, a great deal of effort has gone into investigating the physiological actions of vitamin D and the impact its deficiency has on human health. Despite this intense interest, there is still disagreement on what constitutes the lower boundary of adequacy and on the Recommended Dietary Allowance. There has also been a major push to elucidate the biochemistry of vitamin D, its metabolic pathways and the mechanisms that mediate its action. Originally thought to act by altering the expression of target genes, it was realized in the mid-1980s that some of the actions of vitamin D were too rapid to be accounted for by changes at the genomic level. These rapid non-genomic actions have attracted as much interest as the genomic actions and they have spawned additional questions in an already busy field. This mini-review attempts to summarise the in vitro and in vivo work that has been conducted to characterise the rapid non-genomic actions, the mechanisms that give rise to these properties and the roles that these play in the overall action of vitamin D at the cellular level. Understanding the effects of vitamin D at the cellular level should enable the design of elegant human studies to extract the full potential of vitamin D to benefit human health.

  2. Evolutionary Computational Method of Facial Expression Analysis for Content-based Video Retrieval using 2-Dimensional Cellular Automata

    CERN Document Server

    Geetha, P

    2010-01-01

    In this paper, Deterministic Cellular Automata (DCA) based video shot classification and retrieval is proposed. The deterministic 2D Cellular automata model captures the human facial expressions, both spontaneous and posed. The determinism stems from the fact that the facial muscle actions are standardized by the encodings of Facial Action Coding System (FACS) and Action Units (AUs). Based on these encodings, we generate the set of evolutionary update rules of the DCA for each facial expression. We consider a Person-Independent Facial Expression Space (PIFES) to analyze the facial expressions based on Partitioned 2D-Cellular Automata which capture the dynamics of facial expressions and classify the shots based on it. Target video shot is retrieved by comparing the similar expression is obtained for the query frame's face with respect to the key faces expressions in the database video. Consecutive key face expressions in the database that are highly similar to the query frame's face, then the key faces are use...

  3. Lithium in Medicine: Mechanisms of Action.

    Science.gov (United States)

    Mota de Freitas, Duarte; Leverson, Brian D; Goossens, Jesse L

    2016-01-01

    In this chapter, we review the mechanism of action of lithium salts from a chemical perspective. A description on how lithium salts are used to treat mental illnesses, in particular bipolar disorder, and other disease states is provided. Emphasis is not placed on the genetics and the psychopharmacology of the ailments for which lithium salts have proven to be beneficial. Rather we highlight the application of chemical methodologies for the characterization of the cellular targets of lithium salts and their distribution in tissues. PMID:26860311

  4. Actions of human telomerase beyond telomeres

    Institute of Scientific and Technical Information of China (English)

    Yusheng Cong; Jerry W Shay

    2008-01-01

    Telomerase has fundamental roles in bypassing cellular aging and in cancer progression by maintaining telomere homeostasis and integrity. However, recent studies have led some investigators to suggest novel biochemical properties of telomerase in several essential cell signaling pathways without apparent involvement of its well established function in telomere maintenance. These observations may further enhance our understanding of the molecular actions of telomerase in aging and cancer. This review will provide an update on the extracurricular activities of telomerase in apoptosis, DNA repair, stem cell function, and in the regulation of gene expression.

  5. Markers of cellular senescence. Telomere shortening as a marker of cellular senescence.

    Science.gov (United States)

    Bernadotte, Alexandra; Mikhelson, Victor M; Spivak, Irina M

    2016-01-01

    The cellular senescence definition comes to the fact of cells irreversible proliferation disability. Besides the cell cycle arrest, senescent cells go through some morphological, biochemical, and functional changes which are the signs of cellular senescence. The senescent cells (including replicative senescence and stress-induced premature senescence) of all the tissues look alike. They are metabolically active and possess the set of characteristics in vitro and in vivo, which are known as biomarkers of aging and cellular senescence. Among biomarkers of cellular senescence telomere shortening is a rather elegant frequently used biomarker. Validity of telomere shortening as a marker for cellular senescence is based on theoretical and experimental data. PMID:26805432

  6. Action and Interactiv research

    DEFF Research Database (Denmark)

    Nielsen, Kurt Aagaard; Svensson, Lennart

    The text is written as a first version of editors introduction to a book about action research/interactive research in Nordic countries. You can read abouttrends and contradictions in the history of action research.The authors question the trends and demands a more explicit critical approach...

  7. Action Investment Energy Games

    DEFF Research Database (Denmark)

    Larsen, Kim Guldstrand; Laursen, Simon; Srba, Jiri

    2012-01-01

    We introduce the formalism of action investment energy games where we study the trade-off between investments limited by given budgets and resource constrained (energy) behavior of the underlying system. More specifically, we consider energy games extended with costs of enabling actions and fixed...

  8. Action Learning in China

    Science.gov (United States)

    Marquardt, Michael J.

    2015-01-01

    Action learning was introduced into China less than 20 years ago, but has rapidly become a valuable tool for organizations seeking to solve problems, develop their leaders, and become learning organizations. This article provides an historical overview of action learning in China, its cultural underpinnings, and five case studies. It concludes…

  9. Talk and Action

    DEFF Research Database (Denmark)

    Christensen, Lars Thøger; Morsing, Mette; Thyssen, Ole

    organizational talk and their associated activities, the paper discusses the different ways time shape the relationship between talk and action. Acknowledging that talk gives rise to different expectations over time, we put forward ideal types of organizational strategies for possible talk-action relationships...

  10. Renormalized action improvements

    Energy Technology Data Exchange (ETDEWEB)

    Zachos, C.

    1984-01-01

    Finite lattice spacing artifacts are suppressed on the renormalized actions. The renormalized action trajectories of SU(N) lattice gauge theories are considered from the standpoint of the Migdal-Kadanoff approximation. The minor renormalized trajectories which involve representations invariant under the center are discussed and quantified. 17 references.

  11. An Action Environment

    DEFF Research Database (Denmark)

    van den Brand, Mark; Iversen, Jørgen; Mosses, Peter David

    2004-01-01

    constructs underlying Core ML. The paper also describes the Action Environment, a new environment supporting use and validation of ASDF descriptions. The Action Environment has been implemented on top of the ASF+SDF Meta-Environment, exploiting recent advances in techniques for integration of different...... formalisms, and inheriting all the main features of the Meta-Environment....

  12. Correlating chemical sensitivity and basal gene expression reveals mechanism of action | Office of Cancer Genomics

    Science.gov (United States)

    Changes in cellular gene expression in response to small-molecule or genetic perturbations have yielded signatures that can connect unknown mechanisms of action (MoA) to ones previously established. We hypothesized that differential basal gene expression could be correlated with patterns of small-molecule sensitivity across many cell lines to illuminate the actions of compounds whose MoA are unknown.

  13. Silver Nanoparticle-Mediated Cellular Responses in Various Cell Lines: An in Vitro Model

    Directory of Open Access Journals (Sweden)

    Xi-Feng Zhang

    2016-09-01

    Full Text Available Silver nanoparticles (AgNPs have attracted increased interest and are currently used in various industries including medicine, cosmetics, textiles, electronics, and pharmaceuticals, owing to their unique physical and chemical properties, particularly as antimicrobial and anticancer agents. Recently, several studies have reported both beneficial and toxic effects of AgNPs on various prokaryotic and eukaryotic systems. To develop nanoparticles for mediated therapy, several laboratories have used a variety of cell lines under in vitro conditions to evaluate the properties, mode of action, differential responses, and mechanisms of action of AgNPs. In vitro models are simple, cost-effective, rapid, and can be used to easily assess efficacy and performance. The cytotoxicity, genotoxicity, and biocompatibility of AgNPs depend on many factors such as size, shape, surface charge, surface coating, solubility, concentration, surface functionalization, distribution of particles, mode of entry, mode of action, growth media, exposure time, and cell type. Cellular responses to AgNPs are different in each cell type and depend on the physical and chemical nature of AgNPs. This review evaluates significant contributions to the literature on biological applications of AgNPs. It begins with an introduction to AgNPs, with particular attention to their overall impact on cellular effects. The main objective of this review is to elucidate the reasons for different cell types exhibiting differential responses to nanoparticles even when they possess similar size, shape, and other parameters. Firstly, we discuss the cellular effects of AgNPs on a variety of cell lines; Secondly, we discuss the mechanisms of action of AgNPs in various cellular systems, and try to elucidate how AgNPs interact with different mammalian cell lines and produce significant effects; Finally, we discuss the cellular activation of various signaling molecules in response to AgNPs, and conclude with

  14. Silver Nanoparticle-Mediated Cellular Responses in Various Cell Lines: An in Vitro Model

    Science.gov (United States)

    Zhang, Xi-Feng; Shen, Wei; Gurunathan, Sangiliyandi

    2016-01-01

    Silver nanoparticles (AgNPs) have attracted increased interest and are currently used in various industries including medicine, cosmetics, textiles, electronics, and pharmaceuticals, owing to their unique physical and chemical properties, particularly as antimicrobial and anticancer agents. Recently, several studies have reported both beneficial and toxic effects of AgNPs on various prokaryotic and eukaryotic systems. To develop nanoparticles for mediated therapy, several laboratories have used a variety of cell lines under in vitro conditions to evaluate the properties, mode of action, differential responses, and mechanisms of action of AgNPs. In vitro models are simple, cost-effective, rapid, and can be used to easily assess efficacy and performance. The cytotoxicity, genotoxicity, and biocompatibility of AgNPs depend on many factors such as size, shape, surface charge, surface coating, solubility, concentration, surface functionalization, distribution of particles, mode of entry, mode of action, growth media, exposure time, and cell type. Cellular responses to AgNPs are different in each cell type and depend on the physical and chemical nature of AgNPs. This review evaluates significant contributions to the literature on biological applications of AgNPs. It begins with an introduction to AgNPs, with particular attention to their overall impact on cellular effects. The main objective of this review is to elucidate the reasons for different cell types exhibiting differential responses to nanoparticles even when they possess similar size, shape, and other parameters. Firstly, we discuss the cellular effects of AgNPs on a variety of cell lines; Secondly, we discuss the mechanisms of action of AgNPs in various cellular systems, and try to elucidate how AgNPs interact with different mammalian cell lines and produce significant effects; Finally, we discuss the cellular activation of various signaling molecules in response to AgNPs, and conclude with future perspectives

  15. Silver Nanoparticle-Mediated Cellular Responses in Various Cell Lines: An in Vitro Model.

    Science.gov (United States)

    Zhang, Xi-Feng; Shen, Wei; Gurunathan, Sangiliyandi

    2016-01-01

    Silver nanoparticles (AgNPs) have attracted increased interest and are currently used in various industries including medicine, cosmetics, textiles, electronics, and pharmaceuticals, owing to their unique physical and chemical properties, particularly as antimicrobial and anticancer agents. Recently, several studies have reported both beneficial and toxic effects of AgNPs on various prokaryotic and eukaryotic systems. To develop nanoparticles for mediated therapy, several laboratories have used a variety of cell lines under in vitro conditions to evaluate the properties, mode of action, differential responses, and mechanisms of action of AgNPs. In vitro models are simple, cost-effective, rapid, and can be used to easily assess efficacy and performance. The cytotoxicity, genotoxicity, and biocompatibility of AgNPs depend on many factors such as size, shape, surface charge, surface coating, solubility, concentration, surface functionalization, distribution of particles, mode of entry, mode of action, growth media, exposure time, and cell type. Cellular responses to AgNPs are different in each cell type and depend on the physical and chemical nature of AgNPs. This review evaluates significant contributions to the literature on biological applications of AgNPs. It begins with an introduction to AgNPs, with particular attention to their overall impact on cellular effects. The main objective of this review is to elucidate the reasons for different cell types exhibiting differential responses to nanoparticles even when they possess similar size, shape, and other parameters. Firstly, we discuss the cellular effects of AgNPs on a variety of cell lines; Secondly, we discuss the mechanisms of action of AgNPs in various cellular systems, and try to elucidate how AgNPs interact with different mammalian cell lines and produce significant effects; Finally, we discuss the cellular activation of various signaling molecules in response to AgNPs, and conclude with future perspectives

  16. CELLULAR INTERACTIONS MEDIATED BY GLYCONECTIDS

    Directory of Open Access Journals (Sweden)

    O.Popescu

    1999-01-01

    Full Text Available Cellular interactions involve many types of cell surface molecules and operate via homophilic and/or heterophilic protein-protein and protein-carbohydrate binding. Our investigations in different model-systems (marine invertebrates and mammals have provided direct evidence that a novel class of primordial proteoglycans, named by us gliconectins, can mediate cell adhesion via a new alternative molecular mechanism of polyvalent carbohydrate-carbohydrate binding. Biochemical characterization of isolated and purified glyconectins revealed the presence of specific carbohydrate structures, acidic glycans, different from classical glycosaminoglycans. Such acidic glycans of high molecular weight containing fucose, glucuronic or galacturonic acids, and sulfate groups, originally found in sponges and sea urchin embryos, may represent a new class of carbohydrate carcino-embryonal antigens in mice and humans. Such interactions between biological macromolecules are usually investigated by kinetic binding studies, calorimetric methods, X-ray diffraction, nuclear magnetic resonance, and other spectroscopic analyses. However, these methods do not supply a direct estimation of the intermolecular binding forces that are fundamental for the function of the ligand-receptor association. Recently, we have introduced atomic force microscopy to quantify the binding strength between cell adhesion proteoglycans. Measurement of binding forces intrinsic to cell adhesion proteoglycans is necessary to assess their contribution to the maintenance of the anatomical integrity of multicellular organisms. As a model, we selected the glyconectin 1, a cell adhesion proteoglycan isolated from the marine sponge Microciona prolifera. This glyconectin mediates in vivo cell recognition and aggregation via homophilic, species-specific, polyvalent, and calcium ion-dependent carbohydrate-carbohydrate interactions. Under physiological conditions, an adhesive force of up to 400 piconewtons

  17. Enveloping actions and Takai duality for partial actions

    OpenAIRE

    Abadie, Fernando

    2000-01-01

    We show that any continuous partial action on a topological space has a unique enveloping action, i.e. it is the restriction of a global action. In the case of C^*-algebras we prove that any partial action has an enveloping action up to Morita equivalence. The study of enveloping actions up to Morita equivalence reveals the form that Takai duality takes for partial actions.

  18. Macromolecular lesions and cellular radiation chemistry

    International Nuclear Information System (INIS)

    Our studies of the interaction of densely ionizing particles with macromolecules in the living cell may be divided into four parts: characterization of lesions to cellular DNA in the unmodified Bragg ionization curve; characterization of lesions to cellular DNA in the spread Bragg curve as used in radiation therapy; elucidation of the cellular radiation chemistry characteristic of high vs. low LET radiation qualities; and the introduction of novel techniques designed to give a better understanding of the fundamental properties of induction of lesions and their repair potentials in high LET radiation

  19. Cellular and molecular mechanisms in kidney fibrosis

    Science.gov (United States)

    Duffield, Jeremy S.

    2014-01-01

    Fibrosis is a characteristic feature of all forms of chronic kidney disease. Deposition of pathological matrix in the interstitial space and within the walls of glomerular capillaries as well as the cellular processes resulting in this deposition are increasingly recognized as important factors amplifying kidney injury and accelerating nephron demise. Recent insights into the cellular and molecular mechanisms of fibrogenesis herald the promise of new therapies to slow kidney disease progression. This review focuses on new findings that enhance understanding of cellular and molecular mechanisms of fibrosis, the characteristics of myofibroblasts, their progenitors, and molecular pathways regulating both fibrogenesis and its resolution. PMID:24892703

  20. Cellular chain formation in Escherichia coli biofilms

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk; Klemm, Per

    2009-01-01

    In this study we report on a novel structural phenotype in Escherichia coli biofilms: cellular chain formation. Biofilm chaining in E. coli K-12 was found to occur primarily by clonal expansion, but was not due to filamentous growth. Rather, chain formation was the result of intercellular......; type I fimbriae expression significantly reduced cellular chain formation, presumably by steric hindrance. Cellular chain formation did not appear to be specific to E coli K-12. Although many urinary tract infection (UTI) isolates were found to form rather homogeneous, flat biofilms, three isolates...

  1. Imaging in cellular and tissue engineering

    CERN Document Server

    Yu, Hanry

    2013-01-01

    Details on specific imaging modalities for different cellular and tissue engineering applications are scattered throughout articles and chapters in the literature. Gathering this information into a single reference, Imaging in Cellular and Tissue Engineering presents both the fundamentals and state of the art in imaging methods, approaches, and applications in regenerative medicine. The book underscores the broadening scope of imaging applications in cellular and tissue engineering. It covers a wide range of optical and biological applications, including the repair or replacement of whole tiss

  2. Cellular Signaling Pathways and Their Clinical Reflections

    Directory of Open Access Journals (Sweden)

    N. Ceren Sumer-Turanligil

    2010-06-01

    Full Text Available Cellular signaling pathways have important roles in cellular growth, differentiation, inflammatory response and apoptosis and in regulation of cellular responses under various chemical stimulators. Different proteins which belong to these pathways may be exposed to loss-of-function or gain-of-function mutations; this may lead to many clinical phenotypes including primarily cancer. In this review information about basic working principles of these pathways and diseases related to them are included. [Archives Medical Review Journal 2010; 19(3.000: 180-191

  3. Cellular Cell Bifurcation of Cylindrical Detonations

    Institute of Scientific and Technical Information of China (English)

    HAN Gui-Lai; JIANG Zong-Lin; WANG Chun; ZHANG Fan

    2008-01-01

    Cellular cell pattern evolution of cylindrically-diverging detonations is numerically simulated successfully by solving two-dimensional Euler equations implemented with an improved two-step chemical kinetic model. From the simulation, three cell bifurcation modes are observed during the evolution and referred to as concave front focusing, kinked and wrinkled wave front instability, and self-merging of cellular cells. Numerical research demonstrates that the wave front expansion resulted from detonation front diverging plays a major role in the cellular cell bifurcation, which can disturb the nonlinearly self-sustained mechanism of detonations and finally lead to cell bifurcations.

  4. Action spectra again?

    Science.gov (United States)

    Coohill, T P

    1991-11-01

    Action spectroscopy has a long history and is of central importance to photobiological studies. Action spectra were among the first assays to point to chlorophyll as the molecule most responsible for plant growth and to DNA as the genetic material. It is useful to construct action spectra early in the investigation of new areas of photobiological research in an attempt to determine the wavelength limits of the radiation region causing the studied response. But due to the severe absorption of ultraviolet (UV) radiation by biological samples, UV action spectra were first limited to small cells (bacteria and fungi). Advances in techniques (e.g. single cell culture) and analysis allowed accurate action spectra to be reported even for mammalian cells. But precise analytical action spectra are often difficult to obtain when large, pigmented, or groups of cells are investigated. Here some action spectra are limited in interpretation and merely supply a wavelength vs effect curve. When polychromatic sources are employed, the interpretation of action spectra is even more complex and formidable. But such polychromatic action spectra can be more directly related to ambient responses. Since precise action spectra usually require the completion of a relatively large number of careful experiments using somewhat sophisticated equipment over a range of at least six wavelengths, they are often not pursued. But they remain central to the elucidation of the effect being studied. The worldwide community has agreed that stratospheric ozone is depleting, with the possibility of a consequent rise in the amount of UV-B (290-320 nm) reaching the earth's surface. It is therefore essential that new action spectra be completed for UV-B effects on a large variety of responses of human, animal, and aquatic plant systems. Combining these action spectra with the known amounts of UV-B reaching the biosphere can give rise to solar UV effectiveness spectra that, in turn, can give rise to estimates

  5. 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

    Energy Technology Data Exchange (ETDEWEB)

    Jalade, P

    2005-11-15

    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)

  6. Densities and entropies in cellular automata

    CERN Document Server

    Guillon, Pierre

    2012-01-01

    Following work by Hochman and Meyerovitch on multidimensional SFT, we give computability-theoretic characterizations of the real numbers that can appear as the topological entropies of one-dimensional and two-dimensional cellular automata.

  7. A Matrix Construction of Cellular Algebras

    Institute of Scientific and Technical Information of China (English)

    Dajing Xiang

    2005-01-01

    In this paper, we give a concrete method to construct cellular algebras from matrix algebras by specifying certain fixed matrices for the data of inflations. In particular,orthogonal matrices can be chosen for such data.

  8. The role of sirtuins in cellular homeostasis.

    Science.gov (United States)

    Kupis, Wioleta; Pałyga, Jan; Tomal, Ewa; Niewiadomska, Ewa

    2016-09-01

    Sirtuins are evolutionarily conserved nicotinamide adenine dinucleotide (NAD(+))-dependent lysine deacylases or ADP-ribosyltransferases. These cellular enzymes are metabolic sensors sensitive to NAD(+) levels that maintain physiological homeostasis in the animal and plant cells. PMID:27154583

  9. Optimized Cellular Core for Rotorcraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Patz Materials and Technologies has developed, produced and tested, as part of the Phase-I SBIR, a new form of composite cellular core material, named Interply...

  10. Cellular Defect May Be Linked to Parkinson's

    Science.gov (United States)

    ... 160862.html Cellular Defect May Be Linked to Parkinson's: Study Abnormality might apply to all forms of ... that may be common to all forms of Parkinson's disease. The defect plays a major role in ...

  11. MILLIMETER-WAVE EMISSIVITY OF CELLULAR SYSTEMS

    Science.gov (United States)

    A general analysis has been presented of the millimeter-wave and farinfrared spectroscopic properties of in vivo cellular systems, and of the boson radiative equilibrium with steady-state nonequilibrium molecular systems. The frequency threshhold of spectroscopic properties assoc...

  12. Reasoning about Unreliable Actions

    CERN Document Server

    White, Graham

    2012-01-01

    We analyse the philosopher Davidson's semantics of actions, using a strongly typed logic with contexts given by sets of partial equations between the outcomes of actions. This provides a perspicuous and elegant treatment of reasoning about action, analogous to Reiter's work on artificial intelligence. We define a sequent calculus for this logic, prove cut elimination, and give a semantics based on fibrations over partial cartesian categories: we give a structure theory for such fibrations. The existence of lax comma objects is necessary for the proof of cut elimination, and we give conditions on the domain fibration of a partial cartesian category for such comma objects to exist.

  13. NIL-ANOSOV ACTIONS

    OpenAIRE

    Barbot, Thierry; Maquera, Carlos

    2015-01-01

    We consider Anosov actions of a Lie group $G$ of dimension $k$ on a closed manifold of dimension $k+n.$We introduce the notion of Nil-Anosov action of $G$ (which includes the case where $G$ is nilpotent) and establishes the invariance by the entire group $G$of the associated stable and unstable foliations. We then prove a spectral decomposition Theoremfor such an action when the group $G$ is nilpotent. Finally, we focus on the case where $G$ is nilpotent andthe unstable bundle has codimension...

  14. Freeman's mass action

    OpenAIRE

    Freeman, Walter J III; Kozma, Robert

    2010-01-01

    Freeman's Mass Action (FMA) refers to the collective synaptic actions that neurons in the cortex exert on each other in vast numbers by synchronizing their firing of action potentials. In the aggregate, FMA is a powerful force that creates bursts of cortical neural activity that resemble the vortices of tornadoes and hurricanes. The bursts rapidly and repeatedly retrieve memories and bind them with sensory information into percepts. In this way, FMA expresses and transmits the meaning of sens...

  15. Cellular Restriction Factors of Feline Immunodeficiency Virus

    OpenAIRE

    Carsten Münk; Jörg Zielonka

    2011-01-01

    Lentiviruses are known for their narrow cell- and species-tropisms, which are determined by cellular proteins whose absence or presence either support viral replication (dependency factors, cofactors) or inhibit viral replication (restriction factors). Similar to Human immunodeficiency virus type 1 (HIV-1), the cat lentivirus Feline immunodeficiency virus (FIV) is sensitive to recently discovered cellular restriction factors from non-host species that are able to stop viruses from replicating...

  16. Cellular and molecular mechanisms in kidney fibrosis

    OpenAIRE

    Duffield, Jeremy S.

    2014-01-01

    Fibrosis is a characteristic feature of all forms of chronic kidney disease. Deposition of pathological matrix in the interstitial space and within the walls of glomerular capillaries as well as the cellular processes resulting in this deposition are increasingly recognized as important factors amplifying kidney injury and accelerating nephron demise. Recent insights into the cellular and molecular mechanisms of fibrogenesis herald the promise of new therapies to slow kidney disease progressi...

  17. Apoptotic regulation of epithelial cellular extrusion

    OpenAIRE

    De Andrade, Daniel,; Rosenblatt, Jody

    2011-01-01

    Cellular extrusion is a mechanism that removes dying cells from epithelial tissues to prevent compromising their barrier function. Extrusion occurs in all observed epithelia in vivo and can be modeled in vitro by inducing apoptosis in cultured epithelial monolayers. We established that actin and myosin form a ring that contracts in the surrounding cells that drives cellular extrusion. It is not clear, however, if all apoptotic pathways lead to extrusion and how apoptosis and extrusion are mol...

  18. Cellularity of certain quantum endomorphism algebras

    DEFF Research Database (Denmark)

    Andersen, Henning Haahr; Lehrer, Gus; Zhang, Ruibin

    2015-01-01

    For any ring A˜ such that Z[q±1∕2]⊆A˜⊆Q(q1∕2), let ΔA˜(d) be an A˜-form of the Weyl module of highest weight d∈N of the quantised enveloping algebra UA˜ of sl2. For suitable A˜, we exhibit for all positive integers r an explicit cellular structure for EndUA˜(ΔA˜(d)⊗r). This algebra and its cellular...

  19. Cellular Hyperproliferation and Cancer as Evolutionary Variables

    OpenAIRE

    Alvarado, Alejandro Sánchez

    2012-01-01

    Technological advances in biology have begun to dramatically change the way we think about evolution, development, health and disease. The ability to sequence the genomes of many individuals within a population, and across multiple species, has opened the door to the possibility of answering some long-standing and perplexing questions about our own genetic heritage. One such question revolves around the nature of cellular hyperproliferation. This cellular behavior is used to effect wound heal...

  20. Building mathematics cellular phone learning communities

    OpenAIRE

    Wajeeh M. Daher

    2011-01-01

    Researchers emphasize the importance of maintaining learning communities and environments. This article describes the building and nourishment of a learning community, one comprised of middle school students who learned mathematics out-of-class using the cellular phone. The building of the learning community was led by three third year pre-service teachers majoring in mathematics and computers. The pre-service teachers selected thirty 8th grade students to learn mathematics with the cellular ...

  1. Understanding cisplatin resistance using cellular models.

    OpenAIRE

    STORDAL, BRITTA KRISTINA

    2007-01-01

    PUBLISHED Many mechanisms of cisplatin resistance have been proposed from studies of cellular models of resistance including changes in cellular drug accumulation, detoxification of the drug, inhibition of apoptosis and repair of the DNA adducts. A series of resistant models were developed from CCRF-CEM leukaemia cells with increasing doses of cisplatin from 100 ng/ml. This produced increasing resistance up to 7-fold with a treatment dose of 1.6 ?g/ml. Cisplatin resistance i...

  2. Understanding cisplatin resistance using cellular models

    OpenAIRE

    Stordal, Britta; Davey, Mary

    2007-01-01

    Many mechanisms of cisplatin resistance have been proposed from studies of cellular models of resistance including changes in cellular drug accumulation, detoxification of the drug, inhibition of apoptosis and repair of the DNA adducts. A series of resistant models were developed from CCRF-CEM leukaemia cells with increasing doses of cisplatin from 100 ng/ml. This produced increasing resistance up to 7-fold with a treatment dose of 1.6 microg/ml. Cisplatin resistance in these cells correlated...

  3. On the Behavior Characteristics of Cellular Automata

    Institute of Scientific and Technical Information of China (English)

    CHEN Jin-cai; ZHANG Jiang-ling; FENG Dan

    2005-01-01

    In this paper, the inherent relationships between the running regulations and behavior characteristics of cellular automata are presented; an imprecise taxonomy of such systems is put forward; the three extreme cases of stable systems are discussed; and the illogicalness of evolutional strategies of cellular automata is analyzed. The result is suitable for the emulation and prediction of behavior of discrete dynamics systems; especially it can be taken as an important analysis means of dynamic performance of complex networks.

  4. Cellular Scaling Rules of Insectivore Brains

    OpenAIRE

    Sarko, Diana K.; Catania, Kenneth C.; Leitch, Duncan B.; Kaas, Jon H.; Herculano-Houzel, Suzana

    2009-01-01

    Insectivores represent extremes in mammalian body size and brain size, retaining various “primitive” morphological characteristics, and some species of Insectivora are thought to share similarities with small-bodied ancestral eutherians. This raises the possibility that insectivore brains differ from other taxa, including rodents and primates, in cellular scaling properties. Here we examine the cellular scaling rules for insectivore brains and demonstrate that insectivore scaling rules overla...

  5. Cellular scaling rules of insectivore brains

    OpenAIRE

    Sarko, Diana K.; Catania, Kenneth C.; Leitch, Duncan B.; Kaas, Jon H.; Suzana Herculano-Houzel

    2009-01-01

    Insectivores represent extremes in mammalian body size and brain size, retaining various “primitive” morphological characteristics, and some species of Insectivora are thought to share similarities with small-bodied ancestral eutherians. This raises the possibility that insectivore brains differ from other taxa, including rodents and primates, in cellular scaling properties. Here we examine the cellular scaling rules for insectivore brains and demonstrate that insectivore scaling ...

  6. Cellular scaling rules for primate brains

    OpenAIRE

    Herculano-Houzel, Suzana; Collins, Christine E.; Wong, Peiyan; Kaas, Jon H.

    2007-01-01

    Primates are usually found to have richer behavioral repertoires and better cognitive abilities than rodents of similar brain size. This finding raises the possibility that primate brains differ from rodent brains in their cellular composition. Here we examine the cellular scaling rules for primate brains and show that brain size increases approximately isometrically as a function of cell numbers, such that an 11× larger brain is built with 10× more neurons and ≈12× more nonneuronal cells of ...

  7. Screening action potentials: The power of light

    Directory of Open Access Journals (Sweden)

    Lars eKaestner

    2011-07-01

    Full Text Available Action potentials reflect the concerted activity of all electrogenic constituents in the plasma membrane during the excitation of a cell. Therefore, the action potential is an integrated readout and a promising parameter to detect electrophysiological failures or modifications thereof in diagnosis as well as in drug screens. Cellular action potentials can be recorded by optical approaches. To fulfill the pre-requirements to scale up for e.g. pharmacological screens the following preparatory work has to be provided: (i model cells under investigation need to represent target cells in the best possible manner; (ii optical sensors that can be either small molecule dyes or genetically encoded potential probes need to provide a reliable readout with minimal interaction with the naive behavior of the cells and (iii devices need to be capable to stimulate the cells, read out the signals with the appropriate speed as well as provide the capacity for a sufficient throughput. Here we discuss several scenarios for all three categories in the field of cardiac physiology and pharmacology and provide a perspective to use the power of light in screening cardiac action potentials.

  8. Polymersomes containing quantum dots for cellular imaging

    Directory of Open Access Journals (Sweden)

    Camblin M

    2014-05-01

    Full Text Available Marine Camblin,1 Pascal Detampel,1 Helene Kettiger,1 Dalin Wu,2 Vimalkumar Balasubramanian,1,* Jörg Huwyler1,*1Division of Pharmaceutical Technology, 2Department of Chemistry, University of Basel, Basel, Switzerland*These authors contributed equally to this workAbstract: Quantum dots (QDs are highly fluorescent and stable probes for cellular and molecular imaging. However, poor intracellular delivery, stability, and toxicity of QDs in biological compartments hamper their use in cellular imaging. To overcome these limitations, we developed a simple and effective method to load QDs into polymersomes (Ps made of poly(dimethylsiloxane-poly(2-methyloxazoline (PDMS-PMOXA diblock copolymers without compromising the characteristics of the QDs. These Ps showed no cellular toxicity and QDs were successfully incorporated into the aqueous compartment of the Ps as confirmed by transmission electron microscopy, fluorescence spectroscopy, and fluorescence correlation spectroscopy. Ps containing QDs showed colloidal stability over a period of 6 weeks if stored in phosphate-buffered saline (PBS at physiological pH (7.4. Efficient intracellular delivery of Ps containing QDs was achieved in human liver carcinoma cells (HepG2 and was visualized by confocal laser scanning microscopy (CLSM. Ps containing QDs showed a time- and concentration-dependent uptake in HepG2 cells and exhibited better intracellular stability than liposomes. Our results suggest that Ps containing QDs can be used as nanoprobes for cellular imaging.Keywords: quantum dots, polymersomes, cellular imaging, cellular uptake

  9. Analysis of toxin induced changes in action potential shape for drug development

    OpenAIRE

    Akanda, Nesar; Molnar, Peter; Stancescu, Maria; Hickman, James J.

    2009-01-01

    The generation of an action potential is a complex process in excitable cells which involves the temporal opening and closing of several voltage-dependent ion channels in the cell membrane. The shape of an action potential can carry information concerning the state of the involved ion channels and their relationship to cellular processes. Alteration of these ion channels by the administration of toxins, drugs, and biochemicals can change the action potential’s shape in a specific way which ca...

  10. Normative Action Research

    DEFF Research Database (Denmark)

    Baboroglu, Oguz; Ravn, Ib

    1992-01-01

    This paper presents an argument for an enrichment of action research methodology. To the current state of action research, we add a constructivist epistemological argument, as well as a crucial inspiration from some futures-oriented planning approaches. Within the domain of social....../organizational research, the futures perspective implies that knowledge of the social/organizational world must be based upon images of desirable futures, so-called "futures theories", not causal descriptions of a problematic present. Futures theories identify ends and means for individual and organizational development....... They are generated jointly by the stakeholders of a system and the involved action researchers and are tested every time that the prescriptions for action contained in them are followed by a system's stakeholders....

  11. NSP Action Plans

    Data.gov (United States)

    Department of Housing and Urban Development — NSP Action Plans, also known as Substantial Amendments, contain a description of a grantee’s intended use for NSP funds. The plans contain information on the...

  12. Asthma action plan

    OpenAIRE

    Public Health Agency

    2014-01-01

    This action plans allow each child (or parent/carer) to record his or her asthma treatment to help manage their asthma when they are well, when their symptoms get worse and when they are suffering an asthma attack.

  13. Action Type Deontic Logic

    DEFF Research Database (Denmark)

    Bentzen, Martin Mose

    2014-01-01

    A new deontic logic, Action Type Deontic Logic, is presented. To motivate this logic, a number of benchmark cases are shown, representing inferences a deontic logic should validate. Some of the benchmark cases are singled out for further comments and some formal approaches to deontic reasoning...... are evaluated with respect to the benchmark cases. After that follows an informal introduction to the ideas behind the formal semantics, focussing on the distinction between action types and action tokens. Then the syntax and semantics of Action Type Deontic Logic is presented and it is shown to meet...... the benchmarks. Finally, possibilities for further research are indicated. In the appendix, decidability of the satisfiability of formulas is proved via a technique known from monadic First Order Logic....

  14. Postpartum Depression Action Plan

    Science.gov (United States)

    MENU Return to Web version Postpartum Depression | Postpartum Depression Action Plan Patient __________________________ Physician/NP/PA __________________ Clinic ____________________________ Phone Number ____________________ Choose one area and add other areas as you begin to feel ...

  15. 'Action 2016': AREVA's strategic action plan

    International Nuclear Information System (INIS)

    On December 13, 2011, Luc Oursel, CEO, and Pierre Aubouin, Chief Financial Officer presented the group's strategic plan for the period 2012-2016. The plan has been drawn up collectively and is based on a thorough-going analysis and a realistic assessment of perspectives for all group activities and associated resources. Development of nuclear and renewable energies: the fundamentals are unchanged. In this context, the German decision remains an isolated case and the great majority of nuclear programs around the world have been confirmed. More conservative in its projections than the International Energy Agency, the group expects growth of 2.2% annually, reaching 583 GW of installed nuclear capacity by 2030, against 378 GW today. However, the Fukushima accident will lead to delays in launching new programs. 'Action 2016' plan aims to consolidate AREVA's leadership in nuclear energy and become a leading player in renewable energy. The group's strategic action plan 'Action 2016' is based on the following strategic choices: - commercial priority given to value creation, - selectivity in investments, - strengthening of the financial structure. These demand an improvement in the group's performance by 2015. This plan makes nuclear safety a strategic priority for the industrial and commercial performance of the group. This ambitious performance plan for the period 2012-2016 will give the group the wherewithal to withstand a temporary slowdown in the market resulting from the Fukushima accident and to deliver safe and sustainable growth of the business. The plan sets out the strategic direction for the group's employees for the years ahead: taking advantage of the expected growth in nuclear and renewable energies, targeted investment programs, and return to self-financing as of 2014

  16. Commitment to action. Population Action International.

    Science.gov (United States)

    Squires, S

    1994-01-01

    The national chair of Population Action International (formerly the Population Crisis Committee), Robin Chandler Duke, is a crusader for women's reproductive rights. She was in Bangladesh in 1971 during its civil war. Soldiers would rape young Muslim women, and their families would reject them when they became pregnant. The head of the exiled government agreed to let physicians from IPPF perform abortions on these women, which allowed families to take them back. Opposition to the abortions arose, however. This experience in Bangladesh sparked Ms. Duke's interest in population control. Her years as the wife of a US diplomat granted her access to powerful people worldwide. Her predecessor, retired US Army General Bill Draper, called Ms. Duke from his death bed in 1974 to ask her to be national chair of PAI. She served as a delegate in various international meetings, e.g., the 1980 UNESCO meetings in Belgrade. Spain and Luxembourg honored her for her work of campaigning for women's reproductive rights. She believes that rapid population growth is the most significant problem in the world today. It exacerbates poverty, environmental destruction, and political instability. She believes that universal availability of high quality, voluntary family planning services, including safe abortion, is needed to save humanity from the vicious cycle. Since family planning, sex education, and abortion are the most personal and sensitive parts of people's lives, Population Action frames family planning in the context of basic health care. AIDS complicates the issue, because contraception is no longer limited to birth control. Even though the organization realizes that sexual abstinence is the best way to avoid AIDS, it tries to educate female teenagers not to let boys coerce them to have sex. If they do, have sex Population Action advocates condom use. Ms. Duke cites the family planning successes of Indonesia, Zimbabwe, and Thailand.

  17. Introducere in Action Learning

    DEFF Research Database (Denmark)

    Clausen, Søren Witzel

    In these years action learning has become an increasing aspect of qualifying in service training of teachers in Western European countries. In this article the model of action learning which has been developed by teachers at VIA University College and introduced to the teachers at the SCAN in...... service program will be described and the interaction and the learning aspects in the model will be analyzed....

  18. Reduced Poisson actions

    Institute of Scientific and Technical Information of China (English)

    刘张炬; 杨奇林

    2000-01-01

    A sufficient and necessary condition is given for the action of the quotient of a Poisson-Lie group G on the quotient of a Poisson G-space P to be a Poisson action, where both the Poisson structures on the quotient group and the quotient manifold are induced by Dirac structures. The left invariant Dirac structure and the left invariant tensor descriptions of Poisson homogeneous spaces are proved to be equivalent.

  19. Theater and action research

    DEFF Research Database (Denmark)

    Tofteng, Ditte Maria Børglum; Husted, Mia

    2011-01-01

    Action research on marginalization and exclusion often seeks to examine relations between recognition, respect, and inclusion, but addressing these topics is difficult. Theatre-based action research opens up a new way to communicate and make visible knowledge and experiences from below that have...... and used to highlight and enlarge both critique and dreams in life outside the labor market. The article also discusses some of the reactions the plays received and the formation of knowledge linked to these processes....

  20. Genre as Fictional Action

    DEFF Research Database (Denmark)

    Auken, Sune

    2014-01-01

    The arcticle is an interdisciplinary study between literary and rhetorical genre research. Its starting point is the well-deserved leading position held by Rhetorical Genre Studies (RGS). The article proposes a scholarly collaboration between Literary Studies and RGS and posits one possible...... starting point for this collaboration by utilizing Carolyn Miller´s central concept of "Genre as Social Action" as a way to analyze literary characters´ social actions within narratives through an interpretation of their uses of genre....