Ratio of complex double strand break damage induced by 125IUdR and 123IUdR correlates with experimental in vitro cell killing effectiveness

The overall cellular damage induced by ionising radiation is determined by the number and spatial distribution of initial ionisations and excitations within the critical volume. This paper focuses on the physical and chemical phase of the radiation action chain following the decay of DNA-bound 123I and 125I. Monte Carlo simulations of these nuclides' decay provide electron emission spectra which are used as input data for track structure calculations. In combination with DNA models, these calculations allow the specific radiation source to be characterised in terms of DNA strand break patterns. The distribution of these patterns indicates that 125I produces much more severe breaks than 123I. The ratio of complex DSBs induced by both iodine isotopes correlates with the differences in cell killing effectiveness reported from in vitro survival experiments.     

Stable tracer investigations in humans for assessing the biokinetics of ruthenium and zirconium radionuclides

The interest in the biokinetics of ruthenium and zirconium in humans is justified by the potential radiological risk represented by their radionuclides. Only a few data related to the biokinetics of ruthenium and zirconium in humans are available and, accordingly, the biokinetic models currently recommended by the ICRP for these elements are mainly based on data from animal experiments. The use of stable isotopes as tracers, coupled with a proper analytical technique (nuclear activation analysis with protons) for their determination in biological samples, represents an ethically acceptable methodology for biokinetic investigations, being free from any radiation risk for the volunteer subjects. In this work, the results obtained in eight biokinetic investigations for ruthenium, conducted on a total of three healthy volunteers, and six for zirconium, performed on a total of three subjects, are presented and compared to the predictions of the ICRP models.     

Induced radioactivity in rare-earth permanent magnets at 2.5 GeV electron accelerator

Rare-earth permanent magnets such as Nd₂Fe₁₄B and Sm₂Co₁₇ are the main components of the insertion devices of synchrotron radiation facilities and are used at other particle accelerators. Due to radiation safety concern the induced radioactivity in permanent magnets at a 2.5 GeV electron accelerator were studied with Monte Carlo simulations and experiments. The saturated activity of each radioactive isotope was estimated with FLUKA code (2005 version) and compared with measurement results. Three models of NEOMAX Nd₂Fe₁₄B magnets and one trivial Sm₂Co₁₇ magnet were chosen as the test magnets. The remnant dose rate at 1 m from the magnet and its cooling time dependence are calculated with the induced activities from the view of radiation protection. These are investigated under unique radiation environments due to different target conditions. The transverse distributions of induced radioactivities of several representative isotopes, which were measured at different target conditions, agree well with the electromagnetic shower characteristics at different target conditions as well as the spatial distributions of photon and neutron fluences.     

Monitored steady-state excitation and recovery (MSSER) radiation force imaging using viscoelastic models

Acoustic radiation force imaging methods distinguish tissue structure and composition by monitoring tissue responses to applied radiation force excitations. Although these responses are a complex, multidimensional function of the geometric and viscoelastic nature of tissue, simplified discrete biomechanical models offer meaningful insight to the physical phenomena that govern induced tissue motion. Applying Voigt and standard linear viscoelastic tissue models, we present a new radiation force technique - monitored steady-state excitation and recovery (MSSER) imaging - that tracks both steady-state displacement during prolonged force application and transient response following force cessation to estimate tissue mechanical properties such as elasticity and viscosity. In concert with shear wave elasticity imaging (SWEI) estimates for Young's modulus, MSSER methods are useful for estimating tissue mechanical properties independent of the applied force magnitude. We test our methods in gelatin phantoms and excised pig muscle, with confirmation through mechanical property measurement. Our results measured 10.6 kPa, 14.7 kPa, and 17.1 kPa (gelatin) and 122.4 kPa (pig muscle) with less than 10% error. This work demonstrates the feasibility of MSSER imaging and merits further efforts to incorporate relevant mechanical tissue models into the development of novel radiation force imaging techniques.     

Distribution of equivalent doses to skin of the hands of nuclear medicine personnel

During direct contact with radiation sources, for example in nuclear medicine departments, the skin of the hands of workers is the area most exposed to radiation. Measurements with finger dosemeters containing thermoluminescent detectors showed that doses received may reach values as high as 100 mSv y(-1). The specific nature of work performed with isotopes contributes to the considerable differences in the value of an equivalent dose received by the metacarpus, wrist and fingertips. The annual equivalent doses to which fingertips are exposed may exceed the annual dose limit of 500 mSv.     

On the thermal effects associated with radiation force imaging of soft tissue

Several laboratories are investigating the use of acoustic radiation force to image the mechanical properties of tissue. Acoustic Radiation Force Impulse (ARFI) imaging is one approach that uses brief, high-intensity, focused ultrasound pulses to generate radiation force in tissue. This radiation force generates tissue displacements that are tracked using conventional correlation-based ultrasound methods. The tissue response provides a mechanism to discern mechanical properties of the tissue. The acoustic energy that is absorbed by tissue generates radiation force and tissue heating. A finite element methods model of acoustic heating has been developed that models the thermal response of different tissues during short duration radiation force application. The beam sequences and focal configurations used during ARFI imaging are modeled herein; the results of these thermal models can be extended to the heating due to absorption associated with other radiation force-based imaging modalities. ARFI-induced thermal diffusivity patterns are functions of the transducer f-number, the tissue absorption, and the temporal and spatial spacing of adjacent ARFI interrogations. Cooling time constants are on the order of several seconds. Tissue displacement due to thermal expansion is negligible for ARFI imaging. Changes in sound speed due to temperature changes can be appreciable. These thermal models demonstrate that ARFI imaging of soft tissue is safe, although thermal response must be monitored when ARFI beam sequences are being developed.     

Is radiation protection for the unborn child guaranteed by radiation protection for female workers?

ICRP Publication 88 recommends doses to the embryo and fetus from intakes of radionuclides by the mother for various intake scenarios. Mainly by answering the question 'Is radiation protection for the unborn child guaranteed by radiation protection for female workers?' it has been assessed if the intake scenarios given in ICRP Publication 88 are adequate for radiation protection purposes. This is generally the case, but the consideration of an additional chronic intake scenario for early pregnancy would be helpful. It is demonstrated that following chronic intake by inhalation, for most radionuclides radiation protection for (female) workers is also adequate for protection of the unborn child, considered as a member of the public. However, there are a number of radionuclides for which possible intakes in routine operations should be more restricted (up to 1% of the annual limits on intake for workers in the case of nickel isotopes) to ensure radiation protection for the unborn child.     

Development and validation of a technique for the determination of 226Ra and 228Ra by liquid scintillation in liquid samples

Radium isotopes are dispersed in the environment according to their physicochemical characteristics. Considering their long half-lives and radiological effects, (226)Ra and (228)Ra are very important issues in radiological protection. In Brazil, radium isotopes represent an exposure problem both in nuclear fuel cycle installations and in high natural radiation background areas. The experimental part of this work includes the development of a technique for the determination of (226)Ra and (228)Ra by liquid scintillation with potential application in biological samples. Radium was concentrated and then separated from other constituents of the sample by co-precipitation/precipitation with Ba(Ra)SO(4). The precipitate was filtered and weighted to calculate the chemical yield. The filter containing the precipitate of Ba(Ra)SO(4) was transferred to a scintillation vial. Two methods were used to prepare the sources. The first one consisted of the addition of water (8 ml), Instagel XF (8 ml) and UltimaGold (4 ml) in the vial containing the filter and the precipitate, forming a gel suspension. In the second method, the precipitate was dissolved with 0.2 M ethylene-diamine-tetra-acetic-acid solution (9 ml) and 11 ml of scintillation solution (Optiphase Hisafe 3) was added to the vial, forming an aqueous and an organic phase. The solutions obtained were counted in a low background scintillation spectrometry system (Quantulus) suitable for the detection and identification of both alpha and beta particles for the determination of (226)Ra and (228)Ra. The activity values of (226)Ra and (228)Ra calculated by the two methods are in good agreement with the reference values, indicating that both methods are suitable for the determination of (226)Ra and (228)Ra.     

温度均匀黑体空腔有效发射率近似计算方法（黑体辐射源研究之一）

简要地介绍了国内外在黑体辐射源建立与评价上的发展现状；多种黑体辐射源；多种空腔有效发射率计算方法和模型。通过积分法推导出温度均匀空腔有效发射率计算公式，进一步推导的近似计算公式可以作为对黑体空腔有效发射率估算的依据。     

多光谱辐射测温理论综述

介绍了多光谱辐射测温理论的研究现状，即多光谱辐射测温法的3种数学模型的建立方法和多波长辐射温度计的8种数据处理方法，并分析了各自的特点。     

Prekäre Stoffe

  Precarious Matters. The Radium Economy, Episteme of Risk and the Emergence of Tracer Technique in National Socialism Following the traces of radioactive material is – as scholars have recently shown – a valuable historical approach in order to evaluate the material ’factor’ of science in action. Even though the origins of materials like radium and artificial isotopes are quite different, their circulation is interconnected. A material pathway can be drawn from the radium industry to the scientific rise of artificial isotopes as indicator substances in the 1930s, continuing to the building of networks by German scientists working for the war efforts. Also, this pathway reveals the role of radiation protection in establishing that material culture. Finally, the dynamics of material traces and institutional linkages is shown by the tracer work of biophysicists and radiation biologists working at the Genetic Department of the Kaiser Wilhelm Institute for Brain Research in Berlin and at the Institut de Chimie Nucléaire at Paris, which at that time was occupied by German troops.      

Hydrogen Isotope Separation in Confined Nanospaces: Carbons,Zeolites, Metal–Organic Frameworks,and Covalent Organic Frameworks

One of the greatest challenges of modern separation technology is separating isotope mixtures in high purity. The separation of hydrogen isotopes can create immense economic value by producing valuable deuterium (D) and tritium (T), which are irreplaceable for various industrial and scientific applications. However, current separation methods suffer from low separation efficiency owing to the similar chemical properties of isotopes; thus, high‐purity isotopes are not easily achieved. Recently, nanoporous materials have been proposed as promising candidates and are supported by a newly proposed separation mechanism, i.e., quantum effects. Herein, the fundamentals of the quantum sieving effect of hydrogen isotopes in nanoporous materials are discussed, which are mainly kinetic quantum sieving and chemical‐affinity quantum sieving, including the recent advances in the analytical techniques. As examples of nanoporous materials, carbons, zeolites, metal–organic frameworks, and covalent organic frameworks are addressed from computational and experimental standpoints. Understanding the quantum sieving effect in nanospaces and the tailoring of porous materials based on it will open up new opportunities to develop a highly efficient and advanced isotope separation systems.     

Efficient Radioisotope Energy Transfer by Gold Nanoclusters for Molecular Imaging

Beta‐emitting isotopes Fluorine‐18 and Yttrium‐90 are tested for their potential to stimulate gold nanoclusters conjugated with blood serum proteins (AuNCs). AuNCs excited by either medical radioisotope are found to be highly effective ionizing radiation energy transfer mediators, suitable for in vivo optical imaging. AuNCs synthesized with protein templates convert beta‐decaying radioisotope energy into tissue‐penetrating optical signals between 620 and 800 nm. Optical signals are not detected from AuNCs incubated with Technetium‐99m, a pure gamma emitter that is used as a control. Optical emission from AuNCs is not proportional to Cerenkov radiation, indicating that the energy transfer between the radionuclide and AuNC is only partially mediated by Cerenkov photons. A direct Coulombic interaction is proposed as a novel and significant mechanism of energy transfer between decaying radionuclides and AuNCs.     

Calculation and usage of containment monitor radiation readings during PWR accidents

A computer code named CALCON for calculation of containment monitor radiation readings is introduced. The validity of the code was verified by comparison with data given in IAEA technical documents. The contribution of isotopes to containment readings under conditions of core melt, gap release and normal coolant release were investigated. The conclusions were that the radiation reading in containment is mainly from iodine and noble gases when sprays are off, and the radiation reading is mainly from noble gases when sprays are on, and during the beginning hours when radionuclides are released into containment, the monitor readings will decrease rapidly. Curves of containment radiation readings versus shutdown time for DAYA BAY nuclear power plant were calculated using CALCON.     

Determination of the radionuclide composition and burn-up of high-burn-up WWER-1000 fuel by destructive methods

A sample of WWER-1000 spent nuclear fuel (SNF) with the burn-up of approximately 50 GW day (t U)^?1 was studied by methods of destructive analysis. Data on the content of isotopes of U, Pu, Am, Cm, Nd, and Cs are given. The methods used are briefly described. These include anion exchange and extraction chromatography, thermal ionization mass spectrometry, luminescence analysis, and ??- and ??-ray spectrometry. The main method of the study is isotope dilution followed by mass-spectrometric analysis. The data obtained will be used for developing of a low-waste and low-cost technology for preprocessing of highburn-up SNF and also for checking the accuracy of calculation of heavy actinide content in SNF and for improving computation methods and programs intended for calculation of the SNF nuclide composition in relation to the fuel burn-up in WWER-type reactors. The Nd and Cs isotopes were used as burn-up monitors.     

Applications of isotope effects in solids

This article reviews the current status of the employment of the isotope effect in solids. Diffusion, self-diffusion processes with different isotopes in pure materials and heterostructures (quantum wells), neutron transmutation doping of different semiconducting crystals, optical fiber as well as use isotope-mixed crystals (C, LiH) as the generator of the coherent radiation in the ultraviolet range of the spectrum are the main modern applications of isotope science and engineering. There are briefly discussed the other future applications including modern personal computer, isotope-based quantum computer as well as information storage. We hope to give sufficient references to published work so that the interested reader can easily find the primary literature sources to this rapidly expanding field of solid state physics.     

基于PARAFAC分析和SVM离心泵故障诊断方法

在多尺度平行因子分析理论的基础上,将原始信号经过多尺度小波分解得到三维时频信号,再经平行因子分析得到通道加载因子、时间加载因子和频率加载因子,通过实验分析,后二者可以明显地表征设备正常或故障状态,利用这一特征建立不同状态的离心泵与其对应的时间加载因子和频率加载因子的映射关系,并以此作为改进粒子群算法优化后的支持向量机分类器的特征向量进行故障分类。与小波包能量特征相比,所提的这种诊断方法用于离心泵故障诊断时提取特征更为简便,所提分类器的分类准确率有显著提高,而其复杂度却没有明显增加。     

The Ratio of Plutonium Isotopes Depending on the Burnup of the Fuel from the Fourth Block of the Chernobyl Nuclear Power Plant

The ratio of plutonium isotopes can be used for determining the burnup of nuclear fuel in the fuel-containing masses from the fourth block of the CNPP. The burnup values obtained by two independent methods using cesium and plutonium isotopes are in satisfactory agreement.     

Survey of Industrial,Agricultural, and Medical Applications of Radiometric Gauging and Process Control

Photon and particle radiations (gamma rays, x rays, brems-strahlung, electrons and other charged particles, and neutrons) from radioactive isotopes, x-ray tubes, and accelerators are now widely used in gauging, production control, and other monitoring and metrology devices where avoidance of mechanical contact is desirable. The general principles of radiation gauges, which rely on detection of radiation transmitted by the sample, or on detection of scattered or other secondary radiations produced in the sample, are discussed. Examples of such devices currently used or at least shown to be feasible in industrial, transportation, building, mining, agricultural, medical, and other metrology situations are presented, drawing from a total of 146 selected technical and review paper reference sources here cited.