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Sample records for rayonnements ionisants transferts

  1. Les neuropeptides gastro-intestinaux cibles des effets des rayonnements ionisants : altérations fonctionnelles

    NASA Astrophysics Data System (ADS)

    Linard, C.; Esposito, V.; Wysocki, J.; Griffiths, N. M.

    1998-04-01

    The symptoms associated with exposure to ionizing radiation are nausea, vomiting, diarrhoea. The response of the gut is complex involving modifications of motility and fluid and electrolyte transport. Gastrointestinal regulatory peptides have an important role in these functions. This study showed that radiation-induced tissue variations of neuropeptides have some repercussions on intestinal biological activity of these peptides soon after irradiation. In addition such modifications are also seen a few years after irradiation. Les symptômes associés à l'exposition aux rayonnements ionisants sont des nausées, vomissements et diarrhées. La réponse du système digestif est complexe, impliquant des modifications de la motilité et du transport d'eau et d'électrolytes. les neuropeptides gastro-intestinaux ont un rôle important dans ces fonctions. Cette étude montre que les variations tissulaires de ces neuropeptides induites par l'irradiation ont des répercussions sur l'activité biologique intestinale pour des temps précoces mais que ces perturbations sont encore visibles quelques années après l'irradiation.

  2. Etudes des Reactions de Transfert LITHIUM-7/LITHIUM -6

    NASA Astrophysics Data System (ADS)

    Baddou, Djafer

    Les reactions de transfert de deux nucleons ^7Li/^6Li(^3He, rm p)^8Be/^9Be ont ete effectuees a partir d'um faisceau d'^3He initialement polarise et d'energie incidente egale a 4.58 MeV au centre de la cible. Le faisceau d'^3He est simplement ionise et il est accelere par l'accelerateur Van de Graaff de l'Universite Laval. Ce faisceau d' ^3He est de polarisation egale a 40% et il est obtenu a partir d'une source d'^3He a l'etat metastable. Nous avons decrit la reaction depuis la production et le transport du faisceau initial de l'^3 He jusqu'a la chambre de reaction. Par la suite, nous avons obtenu les distributions angulaires de la section efficace differentielle et du pouvoir d'analyse de ces reactions. Elles ont ete comparees a la theorie DWBA a l'approximation zero. La theorie a montre qu'il s'agit d'un transfert de deux particules independants (neutron, proton) pour le cas de la reaction ^7Li( ^3He,rm p)^9Be et d'un transfert de "cluster" deuteron pour le cas de la reaction ^6Li(^3He, rm p)^8Be. Notons que pour cette reaction l'instabilite du ^8Be ne nous permet pas d'avoir une diffusion elastique permettant la determination des parametres du modele optique entre ce noyau et la particule diffusee. Afin de contourner cette difficulte, nous supposons que le ^8 Be est un noyau compose de deux particules alpha et nous avons teste cette hypothese avec les reactions ^6Li(^3He, rm p)^8Be et ^7Li( ^3He,rm d)^8Be. Nous mentionnons a la fin que nous avons observe que l'etat fondamental de la reaction ^6Li( ^3He,rm p)^8Be et l'etat excite 2.43 MeV de la reaction ^7Li(^3He,rm p)^9Be sont des reactions directes alors que le premier etat excite (2.96 MeV) de la reaction ^6Li(^3He,rm p)^8Be et l'etat fondamental de la reaction ^7Li(^3He,rm p)^9Be peuvent etre domines par une reaction a noyau compose.

  3. Analyse des transferts de chaleur et de masse transitoires dans un arena a l'aide de la methode zonale

    NASA Astrophysics Data System (ADS)

    Daoud, Ahmed

    Cette these presente les resultats d'une etude sur le mouvement de l'air et les transferts thermiques et massiques dans les arenas en regime transitoire et en 3D. Pour la partie aeraulique, il a ete question de developper un modele base sur la methode zonale qui permet de calculer les debits de l'air (dus a la ventilation et aux gradients de temperature) et de l'humidite entre les differentes zones du batiment et de determiner l'age de l'air dans chacune des zones. Pour la partie thermique, un modele de calcul du rayonnement entre les surfaces interieures du batiment qui a ete couple a TRNSYS afin de calculer sur une base annuelle les charges de chauffage et de refrigeration; ces dernieres tiennent compte des transferts radiatif et convectif, de la chaleur latente due a la condensation de l'humidite sur la glace et du surfacage. Le document presente est constitue de 7 chapitres qui peuvent etre resumes comme suit: Les chapitres 1, 2 et 3 sont consacres respectivement: a l'introduction generale, a la revue bibliographique et a la description du batiment modelise. Le chapitre 4 decrit l'approche developpee et la contribution importante qui y est apportee. Il presente l'utilisation de la methode zonale comme une alternative pratique aux methodes CFD car elle permet de realiser des simulations dynamiques sur une annee avec des temps de simulation tres courts et une precision acceptable. Il s'agit d'une approche intermediaire entre les modeles CFD et les modeles a un noeud d'air (considerant la temperature homogene dans un local). Le chapitre 5 est consacre a la methode de resolution numerique. L'outil de simulation a ete developpe en utilisant l'interface du logiciel TRNSYS: Le type 56 de ce logiciel a ete adopte comme modele energetique tandis que les autres modeles ont ete developpes et programmes en utilisant le logiciel MATLAB. Le chapitre 6 presente les resultats de simulation pour un arena sans faux plafond et avec un faux plafond et les resultats de mesures

  4. Strong ionisation in carbon nanowires

    NASA Astrophysics Data System (ADS)

    Kaymak, V.; Pukhov, A.; Shlyaptsev, V. N.; Rocca, J. J.

    2016-04-01

    Surfaces covered with nanostructures, such as nanowire arrays, are shown to facilitate a significantly higher absorption of laser energy as compared to flat surfaces. Due to the efficient coupling of the laser energy, highly energetic electrons are produced, which in turn can emit intense ultrafast X-ray pulses. Full three dimensional PIC simulations are used to analyse the behaviour of arrays of carbon nanowires 400 nm in diameter, irradiated by a 400-nm laser pulse of 60-fs duration at FWHM and a vector potential of α0 = 18. We analyse the ionisation dynamics of the nanowires. The difference of the ionisation strength and structure between linearly and circularly polarised laser beam is investigated. The nanowires are found to be fully ionised after about 30 laser cycles. Circularly polarised light reveals a slightly stronger ionisation effect.

  5. Recombination processes in ionised plasmas

    NASA Astrophysics Data System (ADS)

    Bastin, Robert

    The observational analysis of astrophysical plasmas relies on accurate calculations of the atomic processes involved. The recombination spectra of singly ionised oxygen (O il) and carbon (C il) present excellent tools for investigating regions such as planetary nebulae and H II regions. In this thesis, detailed treatments of the recombination processes of both O II and C II are presented. Using the R-matrix solution to the close coupling equations, I present the results of accurate photoionisation calculations. Bound state energy levels are determined and oscillator strengths calculated for both species. Recombination coefficients were evalu ated for low n and 1, for C II in LS-coupling, and 0 II in intermediate coupling, taking particular care to treat resonances effectively. Sample photoionisation cross-sections are presented for both species, and compared to previous work. A complete radiative-cascade model is treated for both species, in order to determine line emissivities under nebular conditions at a wide range of temperatures and densities. Collisional effects are treated for C II, along with, for the first time, the effects of high temperature dielectronic recombination, allowing the modelling of regions of much higher electron temperature than previous work. The O II calculations were performed under intermediate coupling for the first time, allowing the effects of non-statistical popula tions of the parent ion fine-structure levels and dielectronic recombination onto bound states within this fine-structure to be taken into account in line emissivities. Detailed comparison with previous theoretical work was made for both species. The application of the C II and 0 n recombination spectra to determining tempera ture and densities from the observed spectra of a number of ionised nebulae is considered. The potential for using the new recombination spectra as diagnostic tools to solve some of the key problems in the study of ionised nebulae is demonstrated.

  6. Ionisation as indicator for cosmic ray acceleration

    NASA Astrophysics Data System (ADS)

    Schuppan, F.; Röken, C.; Fedrau, N.; Becker Tjus, J.

    2014-06-01

    Astrospheres and wind bubbles of massive stars are believed to be sources of cosmic rays with energies E ≲ 1 TeV. These particles are not directly detectable, but their impact on surrounding matter, in particular ionisation of atomic and molecular hydrogen, can lead to observable signatures. A correlation study of both gamma ray emission, induced by proton-proton interactions of cosmic ray protons with kinetic energies Ep ≥ 280 MeV with ambient hydrogen, and ionisation induced by cosmic ray protons of kinetic energies Ep < 280 MeV can be performed in order to study potential sources of (sub)TeV cosmic rays.

  7. [Thyroid cancer following exposure to ionising radiation].

    PubMed

    Schlumberger, M; Chevillard, S; Ory, K; Dupuy, C; Le Guen, B; de Vathaire, F

    2011-08-01

    Exposure to ionising radiations during childhood increases the risk of thyroid cancer. Similar risk factors have been found after external radiation exposure or internal contamination with radioactive iodine isotopes. In case of contamination with radioiodines, administration of potassium iodide can prevent thyroid irradiation. PMID:21723770

  8. European Code against Cancer 4th Edition: Ionising and non-ionising radiation and cancer.

    PubMed

    McColl, Neil; Auvinen, Anssi; Kesminiene, Ausrele; Espina, Carolina; Erdmann, Friederike; de Vries, Esther; Greinert, Rüdiger; Harrison, John; Schüz, Joachim

    2015-12-01

    Ionising radiation can transfer sufficient energy to ionise molecules, and this can lead to chemical changes, including DNA damage in cells. Key evidence for the carcinogenicity of ionising radiation comes from: follow-up studies of the survivors of the atomic bombings in Japan; other epidemiological studies of groups that have been exposed to radiation from medical, occupational or environmental sources; experimental animal studies; and studies of cellular responses to radiation. Considering exposure to environmental ionising radiation, inhalation of naturally occurring radon is the major source of radiation in the population - in doses orders of magnitude higher than those from nuclear power production or nuclear fallout. Indoor exposure to radon and its decay products is an important cause of lung cancer; radon may cause approximately one in ten lung cancers in Europe. Exposures to radon in buildings can be reduced via a three-step process of identifying those with potentially elevated radon levels, measuring radon levels, and reducing exposure by installation of remediation systems. In the 4th Edition of the European Code against Cancer it is therefore recommended to: "Find out if you are exposed to radiation from naturally high radon levels in your home. Take action to reduce high radon levels". Non-ionising types of radiation (those with insufficient energy to ionise molecules) - including extremely low-frequency electric and magnetic fields as well as radiofrequency electromagnetic fields - are not an established cause of cancer and are therefore not addressed in the recommendations to reduce cancer risk. PMID:26126928

  9. Apport du rayonnement synchrotron à l'étude de cheveux archéologiques

    NASA Astrophysics Data System (ADS)

    Bertrand, L.; Chevallier, P.; Doucet, J.; Simionovici, A.; Tsoucaris, G.; Walter, P.

    2002-07-01

    La préservation dans certains contextes archéologiques des cheveux humains et des fibres animales est favorisée par leur transformation chimique au contact d'objets métalliques. Afin de mieux comprendre les phénomènes complexes mis en jeu, nous avons étudié expérimentalement la fixation de cations métalliques (Cu et Pb) dans des cheveux modèles à partir de différentes méthodes de caractérisation utilisant le rayonnement X synchrotron. Nous avons ainsi pu mettre en évidence la fixation spécifique d'une partie de ces cations au sein des lipides structurés du cheveu. La comparaison entre échantillons modèles et archéologiques apporte de nouvelles données concernant les premières étapes d'altération des cheveux archéologiques.

  10. Étude des perturbations conduites et rayonnées dans une cellule de commutation

    NASA Astrophysics Data System (ADS)

    Costa, F.; Forest, F.; Puzo, A.; Rojat, G.

    1993-12-01

    The principles used in static conversion and the rise of the performances of the new switching devices contribue to increase the level of electromagnetic noises emitted by electronic converters. We have studied the way how these perturbations are created and coupled through their environment in conducted and radiated mode by a switching cell. This one can work in hard switching, zero current or voltage switching modes. We first outline the general problems of electromagnetic pollution and their metrology in converters. Then we describe the experimental environment. We analyse the mechanisms of generation of parasitic signals in a switching cell related to the electrical constraints and its switching mode. The simulated results, issued of the analytical models obtained, are confronted with the experimental ones. Then we show a method to calculate analytically the E and H near fields. It has been confirmed by experimental results. At last, we present, in a synthetic manner, the main results obtained, relative to the switching mode and the electrical constraints, using a new characterizing method. Theses results will allow the designer to incorporate the electromagnetic considerations in the conception of a converter. Les principes de commutation employés en conversion statique, l'évolution des performances statiques et dynamiques des composants, contribuent à faire des dispositifs de conversion statique de puissants générateurs de perturbations conduites et rayonnées. Nous nous sommes attachés à étudier les mécanismes de génération et de couplage des perturbations, tant en mode conduit que rayonné dans des structures à une seule cellule de commutation et fonctionnant selon les trois principaux modes de commutation : commutation forcée, à zéro de courant (ZCS), et à zéro de tension (ZVS). Après la mise en évidence de la problématique de pollution électromagnétique dans les structures et leur métrologie, nous décrivons l'environnement exp

  11. Determination of structure parameters in molecular tunnelling ionisation model

    NASA Astrophysics Data System (ADS)

    Wang, Jun-Ping; Zhao, Song-Feng; Zhang, Cai-Rong; Li, Wei; Zhou, Xiao-Xin

    2014-04-01

    We extracted the accurate structure parameters in a molecular tunnelling ionisation model (the so-called MO-ADK model) for 23 selected linear molecules including some inner orbitals. The molecular wave functions with the correct asymptotic behaviour are obtained by solving the time-independent Schrödinger equation with B-spline functions and molecular potentials numerically constructed using the modified Leeuwen-Baerends (LBα) model. We show that the orientation-dependent ionisation rate reflects the shape of the ionising orbitals in general. The influences of the Stark shifts of the energy levels on the orientation-dependent ionisation rates of the polar molecules are studied. We also examine the angle-dependent ionisation rates (or probabilities) based on the MO-ADK model by comparing with the molecular strong-field approximation calculations and with recent experimental measurements.

  12. Ionising radiation: are orthopaedic surgeons at risk?

    PubMed Central

    Smith, G. L.; Briggs, T. W.; Lavy, C. B.; Nordeen, H.

    1992-01-01

    Modern orthopaedic trauma practice involves increased exposure of the surgeon to ionising radiation. However, there have been no studies to investigate whether the doses received are within limits for non-classified workers. In this study, whole body, eye and extremity, namely hand, doses were measured in six orthopaedic surgeons during trauma cases requiring the use of X-rays in theatre. None of the subjects approached the recommended maximum dose levels for either the whole body, eyes or hands. This finding is reassuring. In orthopaedics, the limiting dose is that to the hands. This differs from previously studied groups, such as radiologists and cardiologists, in whom the limiting factor is the dose to the lens of the eye. Although current precautions appear to be adequate, safe practice in the future will depend on continuing vigilance and repetition of studies similar to this one as techniques and workloads change. PMID:1416705

  13. Single site double core level ionisation of OCS

    NASA Astrophysics Data System (ADS)

    Hedin, L.; Tashiro, M.; Linusson, P.; Eland, J. H. D.; Ehara, M.; Ueda, K.; Zhaunerchyk, V.; Karlsson, L.; Feifel, R.

    2014-08-01

    Single site O1s, C1s and S2p double ionisation of the OCS molecule has been investigated using a magnetic bottle multi-electron coincidence time-of-flight spectrometer. Photon energies of 1300, 750 and 520 eV, respectively, were used for the ionisation, and spectra were obtained from which the double core ionisation energies could be determined. The energies measured for 1s double ionisation are 1172 eV (O1s-2) and 659 eV (C1s-2). For the S2p double ionisation three dicationic states are expected, 3P, 1D and 1S. The ionisation energies obtained for these states are 373 eV (3P), 380 eV (1D) and 388 eV (1S). The ratio between the double and single core ionisation energies are in all cases equal or close to 2.20. Auger spectra of OCS, associated with the O1s-2, C1s-2 and S2p-2 dicationic states, were also recorded incorporating both electrons emitted as a result of the filling of the two core vacancies. As for other small molecules, the spectra show an atomic-like character with Auger bands located in the range 480-560 eV for oxygen, 235-295 eV for carbon and 100-160 eV for sulphur. The interpretation of the spectra is supported by CASSCF and CASCI calculations. The cross section ratio between double and single core hole creation was estimated as 3.7 × 10-4 for oxygen at 1300 eV, 3.7 × 10-4 for carbon at 750 eV and as 2.2 × 10-3 for sulphur at 520 eV.

  14. Cosmic-ray ionisation of dense molecular clouds

    NASA Astrophysics Data System (ADS)

    Vaupre, Solenn

    2015-07-01

    Cosmic rays (CR) are of tremendous importance in the dynamical and chemical evolution of interstellar molecular clouds, where stars and planets form. CRs are likely accelerated in the shells of supernova remnants (SNR), thus molecular clouds nearby can be irradiated by intense fluxes of CRs. CR protons have two major effects on dense molecular clouds: 1) when they encounter the dense medium, high-energy protons (>280 MeV) create pions that decay into gamma-rays. This process makes SNR-molecular cloud associations intense GeV and/or TeV sources whose spectra mimic the CR spectrum. 2) at lower energies, CRs penetrate the cloud and ionise the gas, leading to the formation of molecular species characteristic of the presence of CRs, called tracers of the ionisation. Studying these tracers gives information on low-energy CRs that are unaccessible to any other observations. I studied the CR ionisation of molecular clouds next to three SNRs: W28, W51C and W44. These SNRs are known to be interacting with the nearby clouds, from the presence of shocked gas, OH masers and pion-decay induced gamma-ray emission. My work includes millimeter observations and chemical modeling of tracers of the ionisation in these dense molecular clouds. In these three regions, we determined an enhanced CR ionisation rate, supporting the hypothesis of an origin of the CRs in the SNR nearby. The evolution of the CR ionisation rate with the distance to the SNR brings valuable constraints on the propagation properties of low-energy CRs. The method used relies on observations of the molecular ions HCO+ and DCO+, which shows crucial limitations at high ionisation. Therefore, I investigated, both through modeling and observations, the chemical abundances of several other species to try and identity alternative tracers of the ionisation. In particular, in the W44 region, observations of N2H+ bring additional constraints on the physical conditions, volatile abundances in the cloud, and the ionisation

  15. Some characteristics of the glutathione cycle revealed by ionising and non-ionising electromagnetic radiation.

    PubMed

    Holt, J A

    1995-10-01

    The cyclic reaction of GSH-->GSSG-->GSH (designated R(exp) or R(e)) obeys the three specific features of life by producing energy in exponential quantities relative to time, is in effect irreversible and is inherited from generation to generation. In multicellular life, this reaction produces the energy for mitosis and is kept in controlled inactivity until needed to maintain perfection of form and function by energising mitosis. The immediate control of Re appears to be feedback process-dependent on the concentration of GSSG. Ultra high-frequency electromagnetic radiation of 434 MHz (UHF) will change Re from inactive to active and, in so doing, it causes resonance and/or fluorescence of the glutathione cycle which changes its radiosensitivity. Re is the primary direct target of ionising radiation and produces the energy for mitosis. Clinical observations suggest that, in the normal cell, Re is inactive and is not killed by 3 x 2700 rads or 6 x 1650 rads yet, when active, its sensitivity value (DO) is approximately 160 rads. Using the standard radiobiological equation of response to ionising radiation, it can be deduced that radiosensitive cancers have two or three Re units active per cell and radioresistance increases in proportion to the number of potentially active Re units per cell. Re appears to be the main cause of cancers' increased conductivity of electricity compared with normal tissue. In cancer therapy, UHF is the best radiosensitiser ever discovered (up to two or more decades). Re is also intelligent compared with non-exponential reactions but cannot be the basis of intellectual brain functions which must be based on non-electrical chemical processes. PMID:8577298

  16. The effectiveness of photocatalytic ionisation disinfection of filter materials.

    PubMed

    Pietrzak, Katarzyna; Gutarowska, Beata

    2013-01-01

    The purpose of this study was to determine the effectiveness of photocatalytic ionisation as a disinfection method for filter materials contaminated by microorganisms, and to assess how air relative humidity (RH), time and microbe type influence the effectiveness of this disinfection. In the quantitative analysis of a used car air filter, bacterial contamination equalled 1.2 x 10(5) cfu/cm2, fungal contamination was 3.8 x 10(6) cfu/cm2, and the isolated microorganisms were Aspergillus niger, Bacillus megaterium, Cladosporium herbarum, Cryptococcus laurenti, Micrococcus sp., Rhodotorula glutinis and Staphylococcus cohnii. In the model experiment, three isolates (C. herbarum, R. glutinis, S. cohnii) and 3 ATCC species (A. niger, E. coli, S. aureus) were used for photocatalytic ionisation disinfection. The conditions of effective photocatalytic ionisation disinfection (R > or = 99.9%) were established as 2-3 h at RH = 77% (bacteria) and 6-24 h at RH = 53% (fungi). RH has an influence on the effectiveness of the photocatalytic disinfection process; the highest effectiveness was obtained for bacteria at RH = 77%, with results 5% higher than for RH = 49%. The studies show that the sensitivity of microorganisms to photocatalytic ionisation disinfection is ordered as follows: Gram-positive bacteria (S. cohnii, S. aureus), Gram-negative bacteria (E. coli), yeasts (R. glutinis), and moulds (C. herbarum, A. niger). Of all the mathematical models used for the description of death dynamics after photocatalytic ionisation disinfection, the Chick-Watson model is the most useful, but for more resistant microorganisms, the delayed Chick-Watson model is highly recommended. It therefore seems, that the presented disinfection method of photocatalytic ionisation can be successfully used to clean filtration materials. PMID:24053016

  17. Binary-Encounter-Bethe ionisation cross sections for simulation of DNA damage by the direct effect of ionising radiation.

    PubMed

    Plante, I; Cucinotta, F A

    2015-09-01

    DNA damage is of crucial importance in the understanding of the effects of ionising radiation. To refine existing DNA damage models, an approach using the Binary-Encounter-Bethe (BEB) cross sections was developed. The differential cross sections for ionisation of the molecular orbitals of the DNA bases, sugars and phosphates are calculated using the electron binding energy, the mean kinetic energy and the occupancy number of each orbital as parameters. The resulting cross section has an analytic form which is quite convenient to use for Monte-Carlo codes that randomly sample the energy loss occurring during an ionisation event. We also describe an algorithm to simulate the interactions of electrons with DNA in the radiation transport code RITRACKS using the integrated BEB cross section for the bases, sugar and phosphates. PMID:25870431

  18. Development of a RILIS ionisation scheme for gold at ISOLDE, CERN

    NASA Astrophysics Data System (ADS)

    Marsh, B. A.; Fedosseev, V. N.; Kosuri, P.

    2006-07-01

    At the ISOLDE on-line isotope separation facility, the resonance ionisation laser ion source (RILIS) can be used to ionise reaction products as they effuse from the target. The RILIS process of laser step-wise resonance ionisation of atoms in a hot metal cavity provides a highly element selective stage in the preparation of the radioactive ion beam. As a result, the ISOLDE mass separators can provide beams of a chosen isotope with greatly reduced isobaric contamination. With the addition of a new three-step ionisation scheme for gold, the RILIS is now capable of ionising 26 of the elements. The optimal scheme was determined during an extensive study of the atomic energy levels and auto-ionising states of gold, carried out by means of in-source resonance ionisation spectroscopy. Details of the ionisation scheme and a summary of the spectroscopy study are presented.

  19. Development of a RILIS ionisation scheme for gold at ISOLDE, CERN

    NASA Astrophysics Data System (ADS)

    Marsh, B. A.; Fedosseev, V. N.; Kosuri, P.

    At the ISOLDE on-line isotope separation facility, the resonance ionisation laser ion source (RILIS) can be used to ionise reaction products as they effuse from the target. The RILIS process of laser step-wise resonance ionisation of atoms in a hot metal cavity provides a highly element selective stage in the preparation of the radioactive ion beam. As a result, the ISOLDE mass separators can provide beams of a chosen isotope with greatly reduced isobaric contamination. With the addition of a new three-step ionisation scheme for gold, the RILIS is now capable of ionising 26 of the elements. The optimal scheme was determined during an extensive study of the atomic energy levels and auto-ionising states of gold, carried out by means of in-source resonance ionisation spectroscopy. Details of the ionisation scheme and a summary of the spectroscopy study are presented.

  20. Occupational Exposure to Natural Sources of Ionising Radiation in Ireland

    NASA Astrophysics Data System (ADS)

    Organo, Catherine; Colgan, Tony; Fenton, David; Synnott, Hugh; Currivan, Lorraine

    2008-08-01

    The Radiological Protection Institute of Ireland (RPII) has recently completed a detailed evaluation of all radiation exposure pathways from sources of both natural and artificial radiation in the Irish environment. This paper presents a compilation of the occupational doses received by Irish workers exposed to natural sources of ionising radiation.

  1. Occupational Exposure to Natural Sources of Ionising Radiation in Ireland

    SciTech Connect

    Organo, Catherine; Colgan, Tony; Fenton, David; Synnott, Hugh; Currivan, Lorraine

    2008-08-07

    The Radiological Protection Institute of Ireland (RPII) has recently completed a detailed evaluation of all radiation exposure pathways from sources of both natural and artificial radiation in the Irish environment. This paper presents a compilation of the occupational doses received by Irish workers exposed to natural sources of ionising radiation.

  2. Analysis of intact bacteria using rapid evaporative ionisation mass spectrometry.

    PubMed

    Strittmatter, Nicole; Jones, Emrys A; Veselkov, Kirill A; Rebec, Monica; Bundy, Jacob G; Takats, Zoltan

    2013-07-14

    An identification system for microorganisms based on recently developed rapid evaporative ionisation mass spectrometry (REIMS) is presented. Nine bacterial species cultured on various growth media were correctly identified to family-, genus-, and species-level based on their different mass spectral fingerprints using a cross-validated maximum margin criterion model. PMID:23736664

  3. Resonance laser-induced ionisation of sodium vapour taking radiative transfer into account

    SciTech Connect

    Kosarev, N I; Shaparev, N Ya

    2006-04-30

    The problem of ionisation of atomic sodium in the field of resonance laser radiation is numerically solved taking radiative transfer into account. Seed electrons are produced due to the mechanism of associative ionisation, then they gain energy in superelastic processes (collisions of the second kind) and initiate the avalanche ionisation of the medium by electron impact. We studied the effect of secondary radiation on the laser pulse propagation upon competition between the ionising and quenching electron collisions with excited atoms, on the kinetics of ionisation-induced vapour bleaching, and the plasma channel expansion in the form of a halo. (interaction of laser radiation with matter)

  4. Ionised outflows in z ~ 2.4 quasar host galaxies

    NASA Astrophysics Data System (ADS)

    Carniani, S.; Marconi, A.; Maiolino, R.; Balmaverde, B.; Brusa, M.; Cano-Díaz, M.; Cicone, C.; Comastri, A.; Cresci, G.; Fiore, F.; Feruglio, C.; La Franca, F.; Mainieri, V.; Mannucci, F.; Nagao, T.; Netzer, H.; Piconcelli, E.; Risaliti, G.; Schneider, R.; Shemmer, O.

    2015-08-01

    Aims: Outflows driven by active galactic nuclei (AGN) are invoked by galaxy evolutionary models to quench star formation and to explain the origin of the relations observed locally between super-massive black holes and their host galaxies. We here aim to detect extended ionised outflows in luminous quasars, where we expect the highest activity both in star formation and in black-hole accretion. Currently, there are only a few studies based on spatially resolved observations of outflows at high redshift, z > 2. Methods: We analysed a sample of six luminous (L > 1047 erg/s) quasars at z ~ 2.4, observed in H-band using the near-IR integral field spectrometer SINFONI at the VLT. We performed a kinematic analysis of the [Oiii] emission line at λ = 5007 Å. Results: We detect fast, spatially extended outflows in five out of six targets. [Oiii]λ5007 has a complex gas kinematic, with blue-shifted velocities of a few hundreds of km s-1 and line widths up to 1500 km s-1. Using the spectroastrometric method, we infer a size of the ionised outflows of up to ~2 kpc. The properties of the ionised outflows, mass outflow rate, momentum rate, and kinetic power, are correlated with the AGN luminosity. The increase in outflow rate with increasing AGN luminosity is consistent with the idea that a luminous AGN pushes away the surrounding gas through fast outflows that are driven by radiation pressure, which depends on the emitted luminosity. Conclusions: We derive mass outflow rates of about 6-700 M⊙ yr-1 for our sample, which are lower than those observed in molecular outflows. The physical properties of ionised outflows show dependences on AGN luminosity that are similar to those of molecular outflows, but indicate that the mass of ionised gas is lower than that of molecular outflows. Alternatively, this discrepancy between ionised and molecular outflows could be explained with different acceleration mechanisms. Based on Observations collected at the European Organisation for

  5. High ionisation absorption in low mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Ponti, G.; Bianchi, S.; Muñoz-Darias, T.; De, K.; Fender, R.; Merloni, A.

    2016-05-01

    The advent of the new generation of X-ray telescopes yielded a significant step forward in our understanding of ionised absorption generated in the accretion discs of X-ray binaries. It has become evident that these relatively weak and narrow absorption features, sporadically present in the X-ray spectra of some systems, are actually the signature of equatorial outflows, which might carry away more matter than that being accreted. Therefore, they play a major role in the accretion phenomenon. These outflows (or ionised atmospheres) are ubiquitous during the softer states but absent during the power-law dominated, hard states, suggesting a strong link with the state of the inner accretion disc, presence of the radio-jet and the properties of the central source. Here, we discuss the current understanding of this field.

  6. Airborne laser-spark for ambient desorption/ionisation.

    PubMed

    Bierstedt, Andreas; Riedel, Jens

    2016-01-01

    A novel direct sampling ionisation scheme for ambient mass spectrometry is presented. Desorption and ionisation are achieved by a quasi-continuous laser induced plasma in air. Since there are no solid or liquid electrodes involved the ion source does not suffer from chemical interferences or fatigue originating from erosive burning or from electrode consumption. The overall plasma maintains electro-neutrality, minimising charge effects and accompanying long term drift of the charged particles trajectories. In the airborne plasma approach the ambient air not only serves as the plasma medium but at the same time also slows down the nascent ions via collisional cooling. Ionisation of the analyte molecules does not occur in the plasma itself but is induced by interaction with nascent ionic fragments, electrons and/or far ultraviolet photons in the plasma vicinity. At each individual air-spark an audible shockwave is formed, providing new reactive species, which expands concentrically and, thus, prevents direct contact of the analyte with the hot region inside the plasma itself. As a consequence the interaction volume between plasma and analyte does not exceed the threshold temperature for thermal dissociation or fragmentation. Experimentally this indirect ionisation scheme is demonstrated to be widely unspecific to the chemical nature of the analyte and to hardly result in any fragmentation of the studied molecules. A vast ensemble of different test analytes including polar and non-polar hydrocarbons, sugars, low mass active ingredients of pharmaceuticals as well as natural biomolecules in food samples directly out of their complex matrices could be shown to yield easily accessible yet meaningful spectra. Since the plasma medium is humid air, the chemical reaction mechanism of the ionisation is likely to be similar to other ambient ionisation techniques. Wir stellen hier eine neue Ionisationsmethode für die Umgebungsionisation (ambient ionisation) vor. Sowohl die

  7. Ionisation of a quantum dot by electric fields

    SciTech Connect

    Eminov, P A; Gordeeva, S V

    2012-08-31

    We have derived analytical formulas for differential and total ionisation probabilities of a two-dimensional quantum dot by a constant electric field. In the adiabatic approximation, we have calculated the probability of this process in the field of a plane electromagnetic wave and in a superposition of constant and alternating electric fields. The imaginary-time method is used to obtain the momentum distribution of the ionisation probability of a bound system by an intense field generated by a superposition of parallel constant and alternating electric fields. The total probability of the process per unit time is calculated with exponential accuracy. The dependence of the results obtained on the characteristic parameters of the problem is investigated. (laser applications and other topics in quantum electronics)

  8. Wedge Absorber Design for the Muon Ionisation Cooling Experiment

    SciTech Connect

    Rogers, C.; Snopok, P.; Coney, L.; Jansson, A.; /Fermilab

    2010-05-01

    In the Muon Ionisation Cooling Experiment (MICE), muons are cooled by ionisation cooling. Muons are passed through material, reducing the total momentum of the beam. This results in a decrease in transverse emittance and a slight increase in longitudinal emittance, but overall reduction of 6d beam emittance. In emittance exchange, a dispersive beam is passed through wedge-shaped absorbers. Muons with higher energy pass through more material, resulting in a reduction in longitudinal emittance as well as transverse emittance. We consider the cooling performance of different wedge materials and geometries and propose a set of measurements that would be made in MICE.We outline the resources these measurements would require and detail some constraints that guide the choice of wedge parameters.

  9. Ionisation of C60: is it temperature dependent?

    NASA Astrophysics Data System (ADS)

    Baba, M. Sai; Narasimhan, T. S. Lakshmi; Balasubramanian, R.; Mathews, C. K.

    1994-01-01

    In a recent paper, Drewello [T. Drewello, W. Kratschmer, M. Fieber-Erdmann and A. Ding, Int. J. Mass Spectrom. Ion Processes, 124 (1993) R1] reported a temperature dependent ionisation cross section for the formation of C2+60 in their photoionisation dynamic studies on C60 using synchrotron radiation. To check this, the ratio of ion intensities of C2+60 to that of C60 was determined as a function of temperature of C60 samples using a Knudsen effusion mass spectrometer. Our results indicate the absence of any temperature dependence of cross section for the formation of C2+60 in the temperature range of measurement (600-800 K) using electron impact ionisation.

  10. IEC STANDARDS FOR INDIVIDUAL MONITORING OF IONISING RADIATION

    SciTech Connect

    Voytchev, Miroslav; Ambrosi, P.; Behrens, R.; Chiaro Jr, Peter John

    2011-01-01

    This paper presents IEC/SC 45B Radiation protection instrumentation and its standards for individual monitoring of ionising radiation: IEC 61526 Ed. 3 for active personal dosemeters and IEC 62387-1 for passive integrating dosimetry systems. The transposition of these standards as CENELEC (European) standards is also discussed together with the collaboration between IEC/SC 45B and ISO/TC 85/SC 2.

  11. Erich Regener and the ionisation maximum of the atmosphere

    NASA Astrophysics Data System (ADS)

    Carlson, P.; Watson, A. A.

    2014-12-01

    In the 1930s the German physicist Erich Regener (1881-1955) did important work on the measurement of the rate of production of ionisation deep under water and in the atmosphere. Along with one of his students, Georg Pfotzer, he discovered the altitude at which the production of ionisation in the atmosphere reaches a maximum, often, but misleadingly, called the Pfotzer maximum. Regener was one of the first to estimate the energy density of cosmic rays, an estimate that was used by Baade and Zwicky to bolster their postulate that supernovae might be their source. Yet Regener's name is less recognised by present-day cosmic ray physicists than it should be, largely because in 1937 he was forced to take early retirement by the National Socialists as his wife had Jewish ancestors. In this paper we briefly review his work on cosmic rays and recommend an alternative naming of the ionisation maximum. The influence that Regener had on the field through his son, his son-in-law, his grandsons and his students, and through his links with Rutherford's group in Cambridge, is discussed in an appendix. Regener was nominated for the Nobel Prize in Physics by Schrödinger in 1938. He died in 1955 at the age of 73.

  12. Electron impact ionisation cross sections for atomic and molecular allotropes of phosphorous and arsenic

    NASA Astrophysics Data System (ADS)

    Bhutadia, Harshad; Chaudhari, Ashok; Vinodkumar, Minaxi

    2015-12-01

    We report electron impact total ionisation cross sections for phosphorous (P), arsenic (As), diphosphorous (P2), diarsenic (As2), tetra phosphorous (P4) and tetra arsenic (As4) from the threshold of the target to 2000 eV. We employed spherical complex optical potential to compute total inelastic cross sections (Qinel). The total ionisation cross section is extracted from the total inelastic cross section using the complex scattering potential-ionisation contribution method. The results of most of the targets studied here compare well with the measurements and the theoretical data wherever available. The correlation between the peak of ionisation cross sections with the number of target electrons and polarisability is also reported. It is observed that the maximum ionisation cross sections depend linearly on the number of target electrons and polarisability of the target. This linear correlation is used to predict the maximum ionisation cross sections for the targets (I2, HI and PF3) where no experimental data are available.

  13. NICIL: Non-Ideal magnetohydrodynamics Coefficients and Ionisation Library

    NASA Astrophysics Data System (ADS)

    Wurster, James

    2016-08-01

    NICIL (Non-Ideal magnetohydrodynamics Coefficients and Ionisation Library) calculates the ionization values and the coefficients of the non-ideal magnetohydrodynamics terms of Ohmic resistivity, the Hall effect, and ambipolar diffusion. Written as a standalone Fortran90 module that can be implemented in existing codes, NICIL is fully parameterizable, allowing the user to choose which processes to include and decide the values of the free parameters. The module includes both cosmic ray and thermal ionization; the former includes two ion species and three species of dust grains (positively charged, negatively charged and neutral), and the latter includes five elements which can be doubly ionized.

  14. Threshold law for positron-atom impact ionisation

    NASA Technical Reports Server (NTRS)

    Temkin, A.

    1982-01-01

    The threshold law for ionisation of atoms by positron impact is adduced in analogy with our approach to the electron-atom ionization. It is concluded the Coulomb-dipole region of the potential gives the essential part of the interaction in both cases and leads to the same kind of result: a modulated linear law. An additional process which enters positron ionization is positronium formation in the continuum, but that will not dominate the threshold yield. The result is in sharp contrast to the positron threshold law as recently derived by Klar on the basis of a Wannier-type analysis.

  15. Romanian medical exposure to ionising radiation in 2012.

    PubMed

    Girjoaba, O; Cucu, A

    2015-07-01

    Medical exposure, the main source of artificial exposure, shows an increasing trend in the last years, manifested both by increasing the number of examinations with ionising radiation and by increasing the patient dose level. Annual results obtained for medical exposure to ionising radiation based on the data collected from Romanian hospitals are useful for the update of the national database and optimisation of diagnostic procedures in radiology and nuclear medicine. Medical exposure level is expressed in terms of annual collective dose and is evaluated from annual frequencies and the average effective dose per procedure for different types of radiological and nuclear medicine procedures. The Romanian hospitals reported during 2012 a number of 5,505,792 radiological examinations and 17,088 diagnostic procedures of nuclear medicine. Based on the data reported, the average effective doses and their contributions to the collective dose were evaluated. The main contributions to the collective dose of the radiological procedures are registered for CT abdomen and pelvis region, followed by thorax CT and head CT examinations. The next positions are fluoroscopic examination of the thorax and gastrointestinal disease and radiographic examination of the lumbar spine and thorax, which in spite of their low effective dose have an important contribution to the collective dose due to the large number of examinations. For nuclear medicine procedures, major contributions to collective dose are given by bone scintigraphy, followed by PET-CT and thyroid scintigraphy. PMID:25848102

  16. EDDIX--a database of ionisation double differential cross sections.

    PubMed

    MacGibbon, J H; Emerson, S; Liamsuwan, T; Nikjoo, H

    2011-02-01

    The use of Monte Carlo track structure is a choice method in biophysical modelling and calculations. To precisely model 3D and 4D tracks, the cross section for the ionisation by an incoming ion, double differential in the outgoing electron energy and angle, is required. However, the double differential cross section cannot be theoretically modelled over the full range of parameters. To address this issue, a database of all available experimental data has been constructed. Currently, the database of Experimental Double Differential Ionisation Cross sections (EDDIX) contains over 1200 digitalised experimentally measured datasets from the 1960s to present date, covering all available ion species (hydrogen to uranium) and all available target species. Double differential cross sections are also presented with the aid of an eight parameter functions fitted to the cross sections. The parameters include projectile species and charge, target nuclear charge and atomic mass, projectile atomic mass and energy, electron energy and deflection angle. It is planned to freely distribute EDDIX and make it available to the radiation research community for use in the analytical and numerical modelling of track structure. PMID:21113060

  17. Sensitivity of LHC experiments to exotic highly ionising particles

    NASA Astrophysics Data System (ADS)

    De Roeck, A.; Katre, A.; Mermod, P.; Milstead, D.; Sloan, T.

    2012-04-01

    The experiments at the Large Hadron Collider (LHC) are able to discover or set limits on the production of exotic particles with TeV-scale masses possessing values of electric and/or magnetic charge such that they behave as highly ionising particles (HIPs). In this paper the sensitivity of the LHC experiments to HIP production is discussed in detail. It is shown that a number of different detection methods are required to investigate as fully as possible the charge-mass range. These include direct detection as the HIPs pass through either passive or active detectors and, in the case of magnetically charged objects, the so-called induction method with which magnetic monopoles which stop in accelerator and detector material could be observed. The benefit of using complementary approaches to HIP detection is discussed.

  18. Hazards of ionising radiation: 100 years of observations on man.

    PubMed Central

    Doll, R.

    1995-01-01

    In November 1895, when Conrad Röntgen serendipitously discovered X-rays, epidemiology was effectively limited to the study of infectious disease. What little epidemiological work was done in other fields was done as part of clinical medicine or under the heading of geographical pathology. The risks from exposure to X-rays and subsequently from other types of ionising radiation were consequently discovered by qualitative association or animal experiment. They did not begin to be quantified in humans until half a century later, when epidemiology emerged as a scientific discipline capable of quantifying risks of non-infectious disease and the scientific world was alerted to the need for assessing the effects of the radiation to which large populations might be exposed by the use of nuclear energy in peace and war. PMID:8519643

  19. Ionisation Equilibrium for the Non-Maxwellian Electron n-Distributions in Solar Flares: Updated Calculations

    NASA Astrophysics Data System (ADS)

    Dzifčáková, Elena; Dudík, Jaroslav

    2015-12-01

    We use the latest available atomic data to calculate the ionisation and recombination rates for the non-Maxwellian n-distributions, which were shown previously to provide a good fit to the enhanced intensities of dielectronic satellite lines during solar flares. The ionisation and recombination coefficients are subsequently used to derive the ionisation equilibrium. To do so, we consider odd values of n ranging from 1 to 19, i.e., from Maxwellian to strongly non-Maxwellian cases. These calculations involve all elements with proton number up to 30, i.e., H to Zn. The n-distributions modify both the ionisation and the recombination rates. The ionisation rates decrease more steeply at lower pseudo-temperatures, while the radiative recombination rate is reduced due to a lower number of low-energy electrons. The peaks of the dielectronic recombination rates become narrower. These changes are reflected in the ionisation equilibrium. Ion abundance peaks become narrower and can also be shifted, mostly towards higher temperatures. The He-like ions are an important exception, as they are formed in a larger temperature range than that for the Maxwellian distribution. The ions Si xiii - xiv used previously for the diagnostics of the n-distributions are affected only weakly, confirming the determination of n. The ionisation equilibria are available as the electronic supplementary material in a format compatible with the CHIANTI database.

  20. Ionisation effect on the electron localisation in the subcycle waveform shaping scheme

    NASA Astrophysics Data System (ADS)

    Wang, Zhuo; Feng, Zhengpeng; Long, Hua

    2015-03-01

    We have theoretically studied the ionisation effect on the asymmetric dissociation of H+2 exposed to the synthesised multicycle infrared pulses of different wavelengths by solving the time-dependent Schr?dinger equation without using the Born-Oppenheimer approximation. It has been demonstrated that the ionisation does slightly influence the electron localisation for the relatively low pulse intensity (less than 1014 W/cm2). However, our further results show that the ionisation effect becomes much more significant when increasing the pulse intensity, leading to a distinctly different mechanism responsible for the enhancement of the electron localisation.

  1. Photo-ionisation mass spectrometry as detection method for gas chromatography. Optical selectivity and multidimensional comprehensive separations.

    PubMed

    Zimmermann, Ralf; Welthagen, Werner; Gröger, Thomas

    2008-03-14

    Mass spectrometry (MS) with soft ionisation techniques (i.e. ionisation without fragmentation of the analyte molecules) for gaseous samples exhibits interesting analytical properties for direct analysis applications (i.e. direct inlet mass spectrometric on-line monitoring) as well as mass spectrometric detection method for gas chromatography (GC-MS). Commonly either chemical ionisation (CI) or field ionisation (FI) is applied as soft ionisation technology for GC-MS. An interesting alternative to the CI and FI technologies methods are photo-ionisation (PI) methods. PI overcomes some of the limitations of CI and FI and furthermore add some unique analytical properties. The resonance enhanced multi-photon ionisation (REMPI) method uses intense UV-laser pulses (wavelength range approximately 350-193 nm) for highly selective, sensitive and soft ionisation of predominately aromatic compounds. The single photon ionisation (SPI) method utilises VUV light (from lamps or laser sources, wavelengths range approximately 150-110 nm) can be used for a universal soft ionisation of organic molecules. In this article the historical development as well as the current status and concepts of gas chromatography hyphenated to photo-ionisation mass spectrometry are reviewed. PMID:17915237

  2. Experimental investigation of ionisation track structure of carbon ions at HIL Warsaw.

    PubMed

    Bantsar, A; Hilgers, G; Pszona, S; Rabus, H; Szeflinski, Z

    2015-09-01

    In view of the upcoming radiation therapy with carbon ions, the ionisation structure of the carbon ion track at the nanometre scale is of particular interest. Two different nanodosimeters capable of measuring track structure of ionising particles in a gas target equivalent to a nanometric site in condensed matter were involved in the presented experimental investigation, namely the NCBJ Jet Counter and the PTB Ion Counter. At the accelerator facility of the HIL in Warsaw, simulated nanometric volumes were irradiated with carbon ions of 45 and 76 MeV of kinetic energy, corresponding to a range in the tissue of ∼85 µm and ∼190 µm, respectively. The filling gas of both nanodosimeters' ionisation volume was molecular nitrogen N2, and the ionisation cluster size distributions, i.e. the statistical distribution of the number of ionizations produced by one single primary carbon ion in the filling gas, were measured for the two primary particle energies. PMID:25897141

  3. Ionisation Chambers and Secondary Emission Monitors at the PROSCAN Beam Lines

    SciTech Connect

    Doelling, Rudolf

    2006-11-20

    PROSCAN, the dedicated new medical facility at PSI using proton beams for the treatment of deep seated tumours and eye melanoma, is now in the commissioning phase. Air filled ionisation chambers in several configurations are used as current monitors, profile monitors, halo, position and loss monitors at the PROSCAN beam lines. Similar monitors based on secondary emission are used for profile and current measurements in the regime where saturation deteriorates the accuracy of the ionisation chambers.

  4. Education and training issues in individual monitoring of ionising radiation.

    PubMed

    Dimitriou, P; Kamenopoulou, V

    2011-03-01

    The present article deals with the education and training (E&T) issues of individual monitoring (IM) of ionising radiation, based on the requirements provided by the Basic Safety Standards Euratom Directive and the European Commission Technical Recommendations for IM of external radiation. The structure and the objectives of E&T programmes addressed to the staff of dosimetry services, in order to allow the recognition and ensure the continuity of expertise are discussed. The necessity for the establishment of a national strategy for building competence in IM through information, education, training and retraining programmes, addressed to the individually monitored personnel is underlined. The train the trainers' concept is recognised as being an important tool for optimising resources and transferring the skills necessary for building competence. The conditions under which an efficient train the trainers' approach can be established are discussed. Examples of curricula concerning the key persons involved in the provision of E&T in occupational radiation protection are also given. PMID:21131663

  5. Dosimetry of ionising radiation in modern radiation oncology

    NASA Astrophysics Data System (ADS)

    Kron, Tomas; Lehmann, Joerg; Greer, Peter B.

    2016-07-01

    Dosimetry of ionising radiation is a well-established and mature branch of physical sciences with many applications in medicine and biology. In particular radiotherapy relies on dosimetry for optimisation of cancer treatment and avoidance of severe toxicity for patients. Several novel developments in radiotherapy have introduced new challenges for dosimetry with small and dynamically changing radiation fields being central to many of these applications such as stereotactic ablative body radiotherapy and intensity modulated radiation therapy. There is also an increasing awareness of low doses given to structures not in the target region and the associated risk of secondary cancer induction. Here accurate dosimetry is important not only for treatment optimisation but also for the generation of data that can inform radiation protection approaches in the future. The article introduces some of the challenges and highlights the interdependence of dosimetric calculations and measurements. Dosimetric concepts are explored in the context of six application fields: reference dosimetry, small fields, low dose out of field, in vivo dosimetry, brachytherapy and auditing of radiotherapy practice. Recent developments of dosimeters that can be used for these purposes are discussed using spatial resolution and number of dimensions for measurement as sorting criteria. While dosimetry is ever evolving to address the needs of advancing applications of radiation in medicine two fundamental issues remain: the accuracy of the measurement from a scientific perspective and the importance to link the measurement to a clinically relevant question. This review aims to provide an update on both of these.

  6. Dosimetry of ionising radiation in modern radiation oncology.

    PubMed

    Kron, Tomas; Lehmann, Joerg; Greer, Peter B

    2016-07-21

    Dosimetry of ionising radiation is a well-established and mature branch of physical sciences with many applications in medicine and biology. In particular radiotherapy relies on dosimetry for optimisation of cancer treatment and avoidance of severe toxicity for patients. Several novel developments in radiotherapy have introduced new challenges for dosimetry with small and dynamically changing radiation fields being central to many of these applications such as stereotactic ablative body radiotherapy and intensity modulated radiation therapy. There is also an increasing awareness of low doses given to structures not in the target region and the associated risk of secondary cancer induction. Here accurate dosimetry is important not only for treatment optimisation but also for the generation of data that can inform radiation protection approaches in the future. The article introduces some of the challenges and highlights the interdependence of dosimetric calculations and measurements. Dosimetric concepts are explored in the context of six application fields: reference dosimetry, small fields, low dose out of field, in vivo dosimetry, brachytherapy and auditing of radiotherapy practice. Recent developments of dosimeters that can be used for these purposes are discussed using spatial resolution and number of dimensions for measurement as sorting criteria. While dosimetry is ever evolving to address the needs of advancing applications of radiation in medicine two fundamental issues remain: the accuracy of the measurement from a scientific perspective and the importance to link the measurement to a clinically relevant question. This review aims to provide an update on both of these. PMID:27351409

  7. Excitation and Ionisation dynamics in high-frequency plasmas

    NASA Astrophysics Data System (ADS)

    O'Connell, D.

    2008-07-01

    Non-thermal low temperature plasmas are widely used for technological applications. Increased demands on plasma technology have resulted in the development of various discharge concepts based on different power coupling mechanisms. Despite this, power dissipation mechanisms in these discharges are not yet fully understood. Of particular interest are low pressure radio-frequency (rf) discharges. The limited understanding of these discharges is predominantly due to the complexity of the underlying mechanisms and difficult diagnostic access to important parameters. Optical measurements are a powerful diagnostic tool offering high spatial and temporal resolution. Optical emission spectroscopy (OES) provides non-intrusive access, to the physics of the plasma, with comparatively simple experimental requirements. Improved advances in technology and modern diagnostics now allow deeper insight into fundamental mechanisms. In low pressure rf discharges insight into the electron dynamics within the rf cycle can yield vital information. This requires high temporal resolution on a nano-second time scale. The optical emission from rf discharges exhibits temporal variations within the rf cycle. These variations are particularly strong, in for example capacitively coupled plasmas (CCPs), but also easily observable in inductively coupled plasmas (ICPs), and can be exploited for insight into power dissipation. Interesting kinetic and non-linear coupling effects are revealed in capacitive systems. The electron dynamics exhibits a complex spatio-temporal structure. Excitation and ionisation, and, therefore, plasma sustainment is dominated through directed energetic electrons created through the dynamics of the plasma boundary sheath. In the relatively simple case of an asymmetric capacitively coupled rf plasma the complexity of the power dissipation is exposed and various mode transitions can be clearly observed and investigated. At higher pressure secondary electrons dominate the

  8. A VLT VIMOS IFU study of the ionisation nebula surrounding the supersoft X-ray source CAL 83

    NASA Astrophysics Data System (ADS)

    Gruyters, P.; Exter, K.; Roberts, T. P.; Rappaport, S.

    2012-08-01

    Context. CAL 83 is a prototype of the class of Super Soft X-ray Sources (SXS). It is a binary consisting of a low mass secondary that is transferring mass onto a white dwarf primary and is the only known SXS surrounded by an ionisation nebula, made up of the interstellar medium (ISM) ionised by the source itself. We study this nebula using integral field spectroscopy. Aims: The study of ionised material can inform us about the source that is responsible for the ionisation, in a way that is complementary to studying the source directly. Since CAL 83 is the only SXS known with an ionisation nebula, we have an opportunity to see if such studies are as useful for SXSs as they have been for other X-ray ionised nebulae. We can use these data to compare to models of how CAL 83 should ionise its surroundings, based on what we know about the source emission spectrum and the physical conditions of the surrounding ISM. Methods: With the VIMOS integral field spectrograph we obtained spectra over a 25 × 25'' field of view, encompassing one quarter of the nebula. Emission line maps - H i, He II λ4686, [OIII] λλ4959,5007, [NII] λλ6548,5683, and [SII] λλ6716,6731 - are produced in order to study the morphology of the ionised gas. We include CAL 83 on diagrams of various diagnostic ion ratios to compare it to other X-ray ionised sources. Finally we computed some simple models of the ionised gas around CAL 83 and compare the predicted to the observed spectra. Results: CAL 83 appears to have a fairly standard ionisation nebula as far as the morphology goes: the edges where H is recombining are strong in the low stage ionisation lines and the central, clumpy regions are stronger in the higher stage ionisation lines. But the He ii emission is unusual in being confined to one side of CAL 83 rather than being homogeneously distributed as with the other ions. We model the CAL 83 nebula with cloudy using model parameters for SXSs found in the literature. The He ii emission does not

  9. Development of a new ionisation chamber, for HP(10) measurement, using Monte-Carlo simulation and experimental methods.

    PubMed

    Silva, H; Cardoso, J; Oliveira, C

    2011-03-01

    An ionisation chamber that directly measures the quantity personal dose equivalent, H(p)(10), is used as a secondary standard in some metrology laboratories. An ionisation chamber of this type was first developed by Ankerhold. Using the Monte-Carlo simulation, the dose in the sensitive volume as a function of the IC dimensions and the effects of the several components of the ionising chamber have been investigated. Based on these results, a new ionising chamber, lighter than the previous ones, is constructed and experimentally tested. PMID:21208934

  10. Bayesian analysis of nanodosimetric ionisation distributions due to alpha particles and protons.

    PubMed

    De Nardo, L; Ferretti, A; Colautti, P; Grosswendt, B

    2011-02-01

    Track-nanodosimetry has the objective to investigate the stochastic aspect of ionisation events in particle tracks, by evaluating the probability distribution of the number of ionisations produced in a nanometric target volume positioned at distance d from a particle track. Such kind of measurements makes use of electron (or ion) gas detectors with detecting efficiencies non-uniformly distributed inside the target volume. This fact makes the reconstruction of true ionisation distributions, which correspond to an ideal efficiency of 100%, non-trivial. Bayesian unfolding has been applied to ionisation distributions produced by 5.4 MeV alpha particles and 20 MeV protons in cylindrical volumes of propane of 20 nm equivalent size, positioned at different impact parameters with respect to the primary beam. It will be shown that a Bayesian analysis performed by subdividing the target volume in sub-regions of different detection efficiencies is able to provide a good reconstruction of the true nanodosimetric ionisation distributions. PMID:21112893

  11. No evidence for large-scale outflows in the extended ionised halo of ULIRG Mrk273

    NASA Astrophysics Data System (ADS)

    Spence, R. A. W.; Zaurín, J. Rodríguez; Tadhunter, C. N.; Rose, M.; Cabrera-Lavers, A.; Spoon, H.; Muñoz-Tuñón, C.

    2016-03-01

    We present deep new GTC/OSIRIS narrow-band images and optical WHT/ISIS long-slit spectroscopy of the merging system Mrk273 that show a spectacular extended halo of warm ionised gas out to a radius of ˜45 kpc from the system nucleus. Outside of the immediate nuclear regions (r > 6 kpc), there is no evidence for kinematic disturbance in the ionised gas: in the extended regions covered by our spectroscopic slits the emission lines are relatively narrow (FWHM ≲ 350 kms^{-1}) and velocity shifts small (|ΔV| ≲250 kms^{-1}). This is despite the presence of powerful near-nuclear outflows (FWHM > 1000 kms^{-1}; |ΔV| > 400 kms^{-1}; r < 6 kpc). Diagnostic ratio plots are fully consistent with Seyfert 2 photo-ionisation to the NE of the nuclear region, however to the SW the plots are more consistent with low-velocity radiative shock models. The kinematics of the ionised gas, combined with the fact that the main structures are aligned with low-surface-brightness tidal continuum features, are consistent with the idea that the ionised halo represents tidal debris left over from a possible triple-merger event, rather than a reservoir of outflowing gas.

  12. Multiphoton ionisation and dissociation of NO 2 by 50 fs laser pulses

    NASA Astrophysics Data System (ADS)

    Singhal, R. P.; Kilic, H. S.; Ledingham, K. W. D.; Kosmidis, C.; McCanny, T.; Langley, A. J.; Shaikh, W.

    1996-04-01

    Multiphoton ionisation and dissociation of NO 2 has been studied experimentally at 375 nm for laser pulse widths of 10 ns and 50 fs. The parent NO 2 ion peak is not seen in the ns data. In all spectra, the main peak observed is due to the ionisation of the NO molecule which results from the dissociation of excited NO 2 formed after absorbing a 375 nm photon. The intensity dependencies of both NO and NO 2 ion peaks have also been measured. The data has been analysed within the context of a rate equation model using published cross-sections and dissociation rates except for the two-photon ionisation cross-section for NO 2 which was chosen to reproduce the NO 2/NO ion signal ratios at 50 fs. The rate equation model provides a good description of the complete set of data. Indirectly, it may be concluded that coherence effects do not play an important role in the multiphoton excitation/ionisation of NO 2. The data also rules out the importance of above-ionisation dissociation in NO 2 — a conclusion which is consistent with previous data at 496 and 248 nm for laser pulse widths ⩾ 300 fs.

  13. Single-stage accelerator mass spectrometer radiocarbon-interference identification and positive-ionisation characterisation

    NASA Astrophysics Data System (ADS)

    Wilcken, K. M.; Freeman, S. P. H. T.; Xu, S.; Dougans, A.

    2013-01-01

    A single-stage accelerator mass spectrometer (SSAMS) is a good alternative to conventional spectrometers based on tandem electrostatic acceleration for radiocarbon measurement and permits experimentation with both negative and positive carbon ions. However, such 14C AMS of either polarity ions is limited by an interference. In the case of anion acceleration we have newly determined this to be summed 13C and 16O by improvising an additional Wien filter on our SSAMS deck. Also, 14C AMS might be improved by removing its dependency on negative-ionisation in a sputter ion source. This requires negative-ionisation of sample atoms elsewhere to suppress the 14N interference, which we accomplish by transmitting initially positive ions through a thin membrane. The ionisation dependence on ion-energy is found to be consistent with previous experimentation with vapours and thicker foils.

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

    NASA Astrophysics Data System (ADS)

    Samson, Ghislain

    2003-06-01

    Au moment ou dans plusieurs pays on travaille a refondre les programmes d'etudes, tant au primaire qu'au secondaire, l'interet pour le transfert renait. Un des concepts fondamentaux en apprentissage consiste en l'habilete a reutiliser de facon consciente et efficace un acquis d'une situation a une autre situation. Cette recherche emane de preoccupations professionnelles au moment ou le chercheur etait enseignant au secondaire. Au cours de ces annees, il lui a ete possible de constater que plusieurs eleves percevaient difficilement les liens presents entre les disciplines mathematiques et scientifiques. Des travaux en psychologie cognitive et plus particulierement selon une perspective du traitement de l'information ont servi de cadre de reference pour evaluer et analyser les capacites de transfert aupres d'eleves de 4e secondaire. Ce cadre de reference permet de formuler le principal objectif qui est de mieux comprendre le processus de transfert chez des eleves en situation de resolution de problemes scientifiques. Cette these s'interesse donc au transfert en tant que phenomene important du processus d'apprentissage au sens de l'integration. La methode de recherche choisie, de nature qualitative, est principalement axee sur l'evaluation de la capacite a transferer des connaissances lors d'une epreuve et d'un entretien. Pour evaluer ce potentiel de transfert, nous avons elabore deux outils: une epreuve en mathematiques et en sciences et un guide d'entretien. Pour la passation de l'epreuve, le chercheur a pu compter sur la collaboration de 130 sujets provenant de deux ecoles. L'entretien complete la prise de donnees avec 13 sujets ayant accepte de poursuivre l'etude. Les donnees recueillies par ces instruments font ensuite l'objet d'une analyse de contenu. En premier lieu, les verbatims de l'epreuve et de l'entretien ont ete transcrits, puis codifies. La correction des reponses fournies pour les problemes resolus s'est faite a partir d'une grille d

  15. The ionisation energy of cyclopentadienone: a photoelectron-photoion coincidence study

    NASA Astrophysics Data System (ADS)

    Ormond, Thomas K.; Hemberger, Patrick; Troy, Tyler P.; Ahmed, Musahid; Stanton, John F.; Ellison, G. Barney

    2015-08-01

    Imaging photoelectron photoion coincidence (iPEPICO) spectra of cyclopentadienone (C5H4=O and C5D4=O) have been measured at the Swiss Light Source Synchrotron (Paul Scherrer Institute, Villigen, Switzerland) at the Vacuum Ultraviolet (VUV) Beamline. Complementary to the photoelectron spectra, photoionisation efficiency curves were measured with tunable VUV radiation at the Chemical Dynamics Beamline at the Advanced Light Source Synchrotron (Lawrence Berkeley National Laboratory, Berkeley, CA, USA). For both experiments, molecular beams diluted in argon and helium were generated from the vacuum flash pyrolysis of o-phenylene sulphite in a resistively heated microtubular SiC flow reactor. The Franck-Condon profiles and ionisation energies were calculated at the CCSD(T) level of theory, and are in excellent agreement with the observed iPEPICO spectra. The ionisation energies of both cyclopentadienone-d0, IE(C5H4=O), and cyclopentadienone-d4, IE(C5D4=O), were observed to be the same: 9.41 ± 0.01 eV. The mass-selected threshold photoelectron spectrum (ms-TPES) of cyclopentadienone reveals that the C=C stretch in the ground state of the cation is excited upon ionisation, supporting computational evidence that the ground state of the cation is ? 2A2, and is in agreement with previous studies. However, the previously reported ionisation potential has been improved considerably in this work. In addition, since o-benzoquinone (o-O=C6H4=O and o-O=C6D4=O) is also produced in this process, its ms-TPES has been recorded. From the iPEPICO and photoionisation efficiency spectra, we infer an adiabatic ionisation energy of IE(o-O=C6H4=O) = 9.3 ± 0.1 eV, but the rather structureless spectrum indicates a strong change in geometry upon ionisation making this value less reliable.

  16. Cosmic ray induced ionisation of a molecular cloud shocked by the W28 supernova remnant

    NASA Astrophysics Data System (ADS)

    Vaupré, S.; Hily-Blant, P.; Ceccarelli, C.; Dubus, G.; Gabici, S.; Montmerle, T.

    2014-08-01

    Cosmic rays are an essential ingredient in the evolution of the interstellar medium, as they dominate the ionisation of the dense molecular gas, where stars and planets form. However, since they are efficiently scattered by the galactic magnetic fields, many questions remain open, such as where exactly they are accelerated, what is their original energy spectrum, and how they propagate into molecular clouds. In this work we present new observations and discuss in detail a method that allows us to measure the cosmic ray ionisation rate towards the molecular clouds close to the W28 supernova remnant. To perform these measurements, we use CO, HCO+, and DCO+ millimetre line observations and compare them with the predictions of radiative transfer and chemical models away from thermodynamical equilibrium. The CO observations allow us to constrain the density, temperature, and column density towards each observed position, while the DCO+/HCO+ abundance ratios provide us with constraints on the electron fraction and, consequently, on the cosmic ray ionisation rate. Towards positions located close to the supernova remnant, we find cosmic ray ionisation rates much larger (≳100) than those in standard galactic clouds. Conversely, towards one position situated at a larger distance, we derive a standard cosmic ray ionisation rate. Overall, these observations support the hypothesis that the γ rays observed in the region have a hadronic origin. In addition, based on CR diffusion estimates, we find that the ionisation of the gas is likely due to 0.1-1 GeV cosmic rays. Finally, these observations are also in agreement with the global picture of cosmic ray diffusion, in which the low-energy tail of the cosmic ray population diffuses at smaller distances than the high-energy counterpart.

  17. A micro-gap, air-filled ionisation chamber as a detector for criticality accident dosimetry.

    PubMed

    Murawski, Ł; Zielczyński, M; Golnik, N; Gryziński, M A

    2014-10-01

    A micro-gap air-filled ionisation chamber was designed for criticality dosimetry. The special feature of the chamber is its very small gap between electrodes of only 0.3 mm. This prevents ion recombination at high dose rates and minimises the influence of gas on secondary particles spectrum. The electrodes are made of polypropylene because of higher content of hydrogen in this material, when compared with soft tissue. The difference between neutron and gamma sensitivity in such chamber becomes practically negligible. The chamber's envelope contains two specially connected capacitors, one for polarising the electrodes and the other for collecting the ionisation charge. PMID:24324250

  18. Dynamics of ionisation and entanglement in the 'atom + quantum electromagnetic field' system

    SciTech Connect

    Sharapova, P R; Tikhonova, O V

    2012-03-31

    The dynamics of a model Rydberg atom in a strong nonclassical electromagnetic field is investigated. The field-induced transitions to the continuum involving different numbers of photons (with intermediate states in the discrete spectrum) are taken into account and the specific features of ionisation in 'squeezed' field states are considered in comparison with the case of classical light. A significant decrease in the ionisation rate is found, which is caused by the interference stabilisation of the atomic system. The entanglement of the atomic and field subsystems, the temporal dynamics of the correlations found, and the possibility of measuring them are analysed.

  19. Examining Pre-Service Teachers' Use of Atomic Models in Explaining Subsequent Ionisation Energy Values

    ERIC Educational Resources Information Center

    Wheeldon, Ruth

    2012-01-01

    Chemistry students' explanations of ionisation energy phenomena often involve a number of non-scientific or inappropriate ideas being used to form causality arguments. Research has attributed this to many science teachers using these ideas themselves (Tan and Taber, in "J Chem Educ" 86(5):623-629, 2009). This research extends this work by…

  20. Destruction of Raman biosignatures by ionising radiation and the implications for life detection on Mars.

    PubMed

    Dartnell, Lewis R; Page, Kristian; Jorge-Villar, Susana E; Wright, Gary; Munshi, Tasnim; Scowen, Ian J; Ward, John M; Edwards, Howell G M

    2012-04-01

    Raman spectroscopy has proven to be a very effective approach for the detection of microorganisms colonising hostile environments on Earth. The ExoMars rover, due for launch in 2018, will carry a Raman laser spectrometer to analyse samples of the martian subsurface collected by the probe's 2-m drill in a search for similar biosignatures. The martian surface is unprotected from the flux of cosmic rays, an ionising radiation field that will degrade organic molecules and so diminish and distort the detectable Raman signature of potential martian microbial life. This study employs Raman spectroscopy to analyse samples of two model organisms, the cyanobacterium Synechocystis sp. PCC 6803 and the extremely radiation resistant polyextremophile Deinococcus radiodurans, that have been exposed to increasing doses of ionising radiation. The three most prominent peaks in the Raman spectra are from cellular carotenoids: deinoxanthin in D. radiodurans and β-carotene in Synechocystis. The degradative effect of ionising radiation is clearly seen, with significant diminishment of carotenoid spectral peak heights after 15 kGy and complete erasure of Raman biosignatures by 150 kGy of ionising radiation. The Raman signal of carotenoid in D. radiodurans diminishes more rapidly than that of Synechocystis, believed to be due to deinoxanthin acting as a superior scavenger of radiolytically produced reactive oxygen species, and so being destroyed more quickly than the less efficient antioxidant β-carotene. This study highlights the necessity for further experimental work on the manner and rate of degradation of Raman biosignatures by ionising radiation, as this is of prime importance for the successful detection of microbial life in the martian near subsurface. PMID:22349404

  1. Study of the mechanism of direct laser desorption/ionisation for some small organic molecules (M < 400 Daltons).

    PubMed

    Benazouz; Hakim; Debrun; Strivay; Weber

    1999-12-15

    Aspects of direct laser desorption/ionisation have been studied for three molecules, aminotriazole (positive ion), dinoterb and ioxynil (negative ion). The samples are deposited on metallic substrates, and a nitrogen laser is used for desorption/ionisation; ion yields are measured with a time-of-flight mass spectrometer. Previous work had shown that ion yields can strongly vary from one substrate to another, and that this variation does not reflect the (calculated) metal surface temperatures. New results obtained in this work indicate that the desorption/ionisation mechanism is linked to the physical state of the substrate surface. Copyright 1999 John Wiley & Sons, Ltd. PMID:10567927

  2. Suppression of the contribution of short trajectories into above-threshold ionisation spectra by a two-colour laser field

    NASA Astrophysics Data System (ADS)

    Vvedenskii, N. V.; Zheltukhin, A. N.; Silaev, A. A.; Knyazeva, D. V.; Manakov, N. L.; Flegel', A. V.; Frolov, M. V.

    2016-04-01

    We have studied spectra of above-threshold ionisation of atoms by a two-colour laser field with collinear linearly polarised components. We have found a sharp (gap-like) dependence of the length of the high-energy plateau in above-threshold ionisation spectra on the relative phase of the two-colour field at comparable intensities of the field components. Using the quasi-classical analysis we have shown that this effect results from the suppression of partial above-threshold ionisation amplitudes, associated with closed classical trajectories of an electron in the laser field, within a certain range of relative phase values.

  3. Theoretical investigation of the ultrafast dissociation of ionised biomolecules immersed in water: direct and indirect effects.

    PubMed

    Gaigeot, M-P; Lopez-Tarifa, P; Martin, F; Alcami, M; Vuilleumier, R; Tavernelli, I; Hervé du Penhoat, M-A; Politis, M-F

    2010-01-01

    Theoretical simulations are particularly well suited to investigate, at a molecular level, direct and indirect effects of ionising radiations in DNA, as in the particular case of irradiation by swift heavy ions such as those used in hadron therapy. In the past recent years, we have developed the modeling at the microscopic level of the early stages of the Coulomb explosion of DNA molecules immersed in liquid water that follows the irradiation by swift heavy ions. To that end, Time-Dependent Density Functional Theory molecular dynamics simulations (TD-DFT MD) have been developed where localised Wannier orbitals are propagated. This latter enables to separate molecular orbitals of each water molecule from the molecular orbitals of the biomolecule. Our main objective is to demonstrate that the double ionisation of one molecule of the liquid sample, either one water molecule from the solvent or the biomolecule, may be in some cases responsible for the formation of an atomic oxygen as a direct consequence of the molecule Coulomb explosion. Our hypothesis is that the molecular double ionisation arising from irradiation by swift heavy ions (about 10% of ionisation events by ions whose velocity is about the third of speed of light), as a primary event, though maybe less probable than other events resulting from the electronic cascading (for instance, electronic excitations, electron attachments), may be systematically more damageable (and more lethal), as supported by experiments that have been carried out in our group in the 1990s (in studies of damages created by K holes in DNA). The chemical reactivity of the produced atomic oxygen with other radicals present in the medium will ultimately lead to chemical products that are harmful to DNA. In the present paper, we review our theoretical methodology in an attempt that the community be familiar with our new approach. Results on the production of atomic oxygen as a result of the double ionisation of water or as a result of

  4. Exploring the Powerful Ionised Wind in the Seyfert Galaxy PG1211+143

    NASA Astrophysics Data System (ADS)

    Pounds, Ken

    2013-10-01

    Highly-ionised high-speed winds in AGN (UFOs) were first detected with XMM-Newton a decade ago, and are now established as a key factor in the study of SMBH accretion, and in the growth and metal enrichment of their host galaxies. However, information on the ionisation and dynamical structure, and the ultimate fate of UFOs remains very limited. We request a 600ks extended XMM-Newton study of the prototype UFO PG1211+143 in AO-13, to obtain high quality EPIC and RGS spectra, to map the flow structure and variability, while seeking evidence for the anticipated interaction with the ISM and possible conversion of the energetic wind to a momentum-driven flow.

  5. Classification of the Spectra of Highly Ionised Atoms During the Last Seven Years

    NASA Astrophysics Data System (ADS)

    Fawcett, B. C.

    1981-10-01

    This review of recent contributions to the classification of the spectra of highly ionised atoms emphasises how major research projects have influenced progress. These projects include experiments on board orbiting space satellites and SKYLAB, those of fusion research (notably involving TOKAMAK devices), studies with giant pulse laser-produced-plasmas and beam-foil spectroscopy. In addition, the large volume of data gathered through the application of traditional methods and the impact of theoretical calculations are discussed. A comprehensive reference list of papers reporting emission line identifications for elements lighter than nickel and ionisation stages higher than the fourth is included, along with references to other bibliographies and compilations of energy levels, or wavelengths and identifications.

  6. The effect of highly ionising particles on the CMS silicon strip tracker

    NASA Astrophysics Data System (ADS)

    Adam, W.; Bergauer, T.; Friedl, M.; Fruehwirth, R.; Hrubec, J.; Krammer, M.; Pernicka, M.; Waltenberger, W.; Beaumont, W.; de Langhe, E.; de Wolf, E.; Tasevsky, M.; Bouhali, O.; Clerbaux, B.; de Lentdecker, G.; Dewulf, J.-P.; Neuckermans, L.; Vander-Velde, C.; Vanlaer, P.; Wickens, J.; D'Hondt, J.; Goorens, R.; Heyninck, J.; Lowette, S.; Tavernier, S.; Van Lancker, L.; Yu, C.; Assouak, S.; Bonnet, J.-L.; Bruno, G.; De-Callatay, B.; De-Favereau-de-Jeneret, J.; Delaere, C.; De-Visscher, S.; Favart, D.; Gregoire, G.; Keutgen, Th.; Leibenguth, G.; Lemaitre, V.; Michotte, D.; Militaru, O.; Ninane, A.; Ovyn, S.; Piotrzkowski, K.; Roberfroid, V.; Rouby, X.; Van-der-Aa, O.; Vander-Donckt, M.; Boulogne, I.; Daubie, E.; Defontaines, F.; Herquet, P.; Czellar, S.; Härkönen, J.; Karimäki, V.; Katajisto, H.; Linden, T.; Luukka, P.; Lampen, T.; Mäenpää, T.; Tuominen, E.; Tuominiemi, J.; Tuuva, T.; Ageron, M.; Chabanat, E.; Contardo, D.; Estre, N.; Haroutunian, R.; Lumb, N.; Mirabito, L.; Perries, S.; Trocme, B.; Blaes, R.; Charles, F.; Drouhin, F.; Ernenwein, J. P.; Fontaine, J. C.; Berst, J. D.; Brom, J. M.; Didierjean, F.; Goerlach, U.; Gross, L.; Juillot, P.; Lounis, A.; Maazouzi, C.; Olivetto, C.; Strub, R.; Vanhove, P.; Vintache, D.; Adolphi, R.; Brauer, R.; Braunschweig, W.; Esser, H.; Feld, L.; Heister, A.; Karpinski, W.; Klein, K.; König, S.; Kukulies, C.; Olzem, J.; Ostaptchouk, A.; Pandoulas, D.; Pierschel, G.; Raupach, F.; Schael, S.; Schultz von Dratzig, A.; Schwering, G.; Siedling, R.; Thomas, M.; Wlochal, M.; Beissel, F.; Boffin, K.-D.; Duda, M.; Flossdorf, A.; Flugge, G.; Franke, T.; Hangarter, K.; Hegner, B.; Hermanns, Th.; Kasselmann, S.; Kress, Th.; Linn, A.; Mnich, J.; Nowack, A.; Poettgens, M.; Pooth, O.; Reinhold, B.; Bleyl, M.; Holm, U.; Klanner, R.; Pein, U.; Schleper, P.; Schirm, N.; Steinbrück, G.; Stoye, M.; Tesch, S.; van Staa, R.; Wick, K.; Atz, B.; Barvich, T.; Blum, P.; de Boer, W.; Boegelspacher, F.; Dirkes, G.; Fahrer, M.; Fernandez, J.; Frey, M.; Furgeri, A.; Grigoriev, E.; Hartmann, F.; Heier, S.; Muller, T.; Ortega-Gomez, T.; Simonis, H.-J.; Steck, P.; Theel, A.; Weiler, T.; Zhukov, V.; Creanza, D.; De Filippis, N.; de Palma, M.; De Robertis, G.; Fiore, L.; Giordano, D.; Maggi, G.; Mennea, M.; My, S.; Radicci, V.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Albergo, S.; Bellini, V.; Chiorboli, M.; Costa, S.; Potenza, R.; Sutera, C.; Tricomi, A.; Tuvè, C.; Bocci, A.; Ciulli, V.; Civinini, C.; D'Alessandro, R.; Focardi, E.; Landi, G.; Macchiolo, A.; Magini, N.; Mersi, S.; Marchettini, C.; Meschini, M.; Paoletti, S.; Parrini, G.; Ranieri, R.; Sani, M.; Bacchetta, N.; Bisello, D.; Candelori, A.; Dorigo, T.; Giubilato, P.; Kaminsky, A.; Loreti, M.; Nigro, M.; Paccagnella, A.; Rando, R.; Angarano, M. M.; Babucci, E.; Benedetti, D.; Biasini, M.; Bilei, G. M.; Brunetti, M. T.; Checcucci, B.; Dinu, N.; Fanò, L.; Giorgi, M.; Lariccia, P.; Mantovani, G.; Postolache, V.; Puscalau, M.; Ricci, D.; Santinelli, R.; Santocchia, A.; Servoli, L.; Zucchetti, C.; Azzurri, P.; Bagliesi, G.; Basti, A.; Bernardini, J.; Boccali, T.; Borrello, L.; Bosi, F.; Castaldi, R.; D'Alfonso, M.; Dell'Orso, R.; Dutta, S.; Foa, L.; Gennai, S.; Giammanco, A.; Giassi, A.; Lomtadze, T.; Mangano, B.; Messineo, A.; Moggi, A.; Palla, F.; Palmonari, F.; Raffaelli, F.; Rizzi, A.; Rizzi, D.; Segneri, G.; Sentenac, D.; Sguazzoni, G.; Spagnolo, P.; Tonelli, G.; Verdini, P. G.; Biino, C.; Costa, M.; Demaria, N.; Favro, G.; Trapani, P.; Peroni, C.; Romero, A.; Migliore, E.; Abbaneo, D.; Ahmed, F.; Bartalini, P.; Bernardino-Rodriguez, N.; Breuker, H.; Buchmuller, O.; Carrone, E.; Cattai, A.; Chierici, R.; Cucciarelli, S.; Dierlamm, A.; Eppard, M.; Frey, A.; Gill, K.; Grabit, R.; Honma, A.; Huhtinen, M.; Magazzu, G.; Mannelli, M.; Marchioro, A.; Onnela, A.; Perea-Solano, B.; Petagna, P.; Postema, H.; Risoldi, M.; Rolandi, G.; Siegrist, P.; Troska, I.; Tsirou, A.; Vasey, F.; Weber, M.; Wittmer, B.; Bertl, W.; Gabathuler, K.; Horisberger, R.; Kästli, H.-Ch.; Kotlinski, D.; MacPherson, A.; Rohe, T.; Freudenreich, K.; Lustermann, W.; Pauss, F.; Eichler, R.; Erdmann, W.; Grab, C.; Schoning, A.; Amsler, C.; Chiochia, V.; Dorokhov, A.; Hörmann, C.; Pruys, H.; Prokofiev, K.; Regenfus, C.; Robmann, P.; Speer, T.; Bell, K. W.; Coughlan, J.; French, M.; Halsall, R.; Jones, L.; Pearson, M.; Rogers, G.; Tomalin, I.; Bainbridge, R.; Barrillon, P.; Colling, D.; Dris, S.; Foudas, C.; Fulcher, J.; Hall, G.; Iles, G.; Jones, J.; Leaver, J.; Macevoy, B. C.; Noy, M.; Raymond, D. M.; Takahashi, M.; Zorba, O.; Barnett, B.; Chien, C.-Y.; Kim, D. W.; Liang, G.; Swartz, M.; Atac, M.; Demarteau, M.; Joshi, U.; Kwan, S.; Spiegel, L.; Tkaczyk, S.; Gerber, C. E.; Shabalina, E.; Ten, T.; Lander, R.; Pellett, D.; Gobbi, B.; Kubantsev, M.; Malik, S.; Tilden, R.; Baringer, P.; Bean, A.; Christofek, L.; Coppage, D.; Bolton, T. A.; Demina, R.; Kahl, W. E.; Khanov, A.; Korjenevski, S.; Pukhaeva, N.; Reay, N. W.; Rizatdinova, F.; Sidwell, R. A.; Stanton, N. R.; Cremaldi, L.; Sanders, D.; Bartz, E.; Doroshenko, J.; Koeth, T.; Perera, L.; Schnetzer, S.; Stone, R.; Worm, S.; Gartung, P.; Hanson, G. G.; Jeng, G. Y.; Páztor, G.; Eusebi, R.; Halkiadakis, E.; Hocker, A.; Tipton, P.; Affolder, A.; Campagnari, C.; Hale, D.; Incandela, J.; Kyre, S.; Lamb, J.; Taylor, R.; White, D.; Bolla, G.; Bortoletto, D.; Garfinkel, A.; Rott, C.; Roy, A.

    2005-05-01

    Inelastic nuclear collisions of hadrons incident on silicon sensors can generate secondary highly ionising particles (HIPs) and deposit as much energy within the sensor bulk as several hundred minimum ionising particles. The large signals generated by these 'HIP events' can momentarily saturate the APV25 front-end readout chip for the silicon strip tracker (SST) sub-detector of the compact muon solenoid (CMS) experiment, resulting in deadtime in the detector readout system. This paper presents studies of this phenomenon through simulation, laboratory measurements and dedicated beam tests. A proposed change to a front-end component to reduce the APV25 sensitivity to HIP events is also examined. The results are used to infer the expected effect on the performance of the CMS SST at the future large hadron collider. The induced inefficiencies are at the percent level and will have a negligible effect on the physics performance of the SST.

  7. The Interplay Between Molecular and Ionised Gas Surrounding the Massive Embedded Star AFGL 4176

    NASA Astrophysics Data System (ADS)

    Johnston, Katharine G.; Beuther, Henrik; Linz, Hendrik; Boley, P.; Robitaille, Thomas P.; Keto, E.; Wood, K.; van Boekel, R.

    In order to investigate whether the feedback produced by photo-ionisation has an important effect on the geometry of the circumstellar dust and gas around forming massive stars, we have observed the luminous southern embedded star AFGL 4176 in transitions of NH3 and the hydrogen recombination line H68α. We present our preliminary results, which show a compact HII region embedded in a parsec-scale (radius ˜ 0.7 pc) rotating envelope/torus. In addition, the HII region is found to be offset from the centre of the envelope, and the velocity gradient in the ionised gas is not aligned with the rotation axis of the envelope, suggesting complex dynamics and multiplicity.

  8. The nature of the ionised nebula surrounding the red supergiant W26

    NASA Astrophysics Data System (ADS)

    Wesson, Roger

    2015-08-01

    The red supergiant W26 in the massive star cluster Westerlund 1 is surrounded by a compact ionised nebula. This is unique among RSGs, and the excitation mechanism of the nebula is not yet known - it may be ionised by an unseen compact companion, or by a nearby blue supergiant. We present new observations of the nebula: high resolution spatially resolved spectra taken with FLAMES at the VLT show that the nebula is a ring, with velocities consistent with that expected for red supergiant ejecta, and ruling out the possibility of a Luminous Blue Variable-type eruption preceding the RSG phase as the origin of the nebula. A triangular patch of nebulosity outside the ring appears to be associated with W26, and may be material stripped from the expanding ring by the cumulative cluster wind and radiation field.

  9. The effect of electrospray solvent composition on desorption electrospray ionisation (DESI) efficiency and spatial resolution.

    PubMed

    Green, F M; Salter, T L; Gilmore, I S; Stokes, P; O'Connor, G

    2010-04-01

    In desorption electrospray ionisation (DESI) the interaction between the electrospray and the surface is key to two important analytical parameters, the spatial resolution and the sensitivity. We evaluate the effect of the electrospray solvent type, organic solvent fraction with water, analyte solubility and substrate wettability on DESI erosion diameter and material transferral into useful ion signal. To do this five amino acids, glycine, alanine, valine, leucine and phenylalanine are prepared as thin films on three substrates, UV/ozone treated glass, glass and polytetrafluoroethylene (PTFE). Four different solvents, acetonitrile (ACN), methanol (MeOH), ethanol (EtOH) and propan-2-ol (IPA), are used with organic solvent fractions with water varying from 0.1 to 1. These model systems allow the solubility or wettability to be kept constant as other parameters are varied. Additionally, comparison with electrospray ionisation (ESI) allows effects of ionisation efficiency to be determined. It is shown that the DESI efficiency is linearly dependent on the solubility (for these materials at least) and for analytes with solubilities below 1.5 g kg(-1), additional strategies may be required for DESI to be effective. We show that the DESI erosion diameter improves linearly with organic solvent fraction, with an organic solvent fraction of 0.9 instead of 0.5 leading to a 2 fold improvement. Furthermore, this leads to a 35 fold increase in DESI efficiency, defined as the molecular ion yield per unit area. It is shown that these improvements correlate with smaller droplet sizes rather than surface wetting or ionisation. PMID:20349538

  10. Gain Calculations for Inner-Shell Lasing by Electron Collisional Ionisation

    NASA Astrophysics Data System (ADS)

    Upcraft, L. M.

    2002-11-01

    Current high power femtosecond lasers have been shown to produce electron pulses which may be appropriate for the pumping of X-Ray lasers through collisional ionisation. Non-radiative Coster-Kronig type decay processes may be fast enough to form an inverted state and allow X-ray lasing within the biologically interesting "water window". Calculations of the atomic processes in metallic Ti, Mn and Cu are presented that potentially useable gains on the M1 - L3 transition.

  11. Occupational exposure to ionising radiation and mortality among workers of the former Spanish Nuclear Energy Board.

    PubMed Central

    Rodríguez Artalejo, F; Castaño Lara, S; de Andrés Manzano, B; García Ferruelo, M; Iglesias Martín, L; Calero, J R

    1997-01-01

    OBJECTIVES: Firstly, to ascertain whether mortality among workers of the former Spanish Nuclear Energy Board (Junta de Energía Nuclear-JEN) was higher than that for the Spanish population overall; and secondly, if this were so, to ascertain whether this difference was associated with exposure to ionising radiation. METHODS: A retrospective follow up of a cohort of 5657 workers was carried out for the period 1954-92. Cohort mortality was compared with that for the Spanish population overall, with standardised mortality ratios (SMRs) adjusted for sex, age, and calendar period. Also, Poisson models were used to analyse mortality from lung cancer in the cohort by level of exposure to ionising radiation. RESULTS: Workers' median and mean cumulative exposures were 4.04 and 11.42 mSv, respectively. Mean annual exposure was 1.33 mSv. Excess mortality due to bone tumours was found for the cohort as a whole (six deaths observed; SMR 2.95; 95% confidence interval (95% CI) 1.08 to 6.43). Among miners, excess mortality was found for non-malignant respiratory diseases (SMR 2.94; 95% CI 2.27 to 3.75), and for lung cancer bordering on statistical significance (SMR 1.50; 95% CI 0.96 to 2.23; P = 0.055). Relative risks of dying of lung cancer from ionising radiation in the dose quartiles 2, 3, and 4 versus the lowest dose quartile, were 1.00, 1.64, and 0.94, respectively. CONCLUSIONS: Excess mortality from lung cancer was found among JEN miners. Nevertheless, no clear relation was found between mortality from lung cancer and level of exposure to ionising radiation in the JEN cohort. Continued follow up of the cohort is required to confirm excess mortality from bone tumours. PMID:9155782

  12. Analysis of oak tannins by liquid chromatography-electrospray ionisation mass spectrometry.

    PubMed

    Mämmelä, P; Savolainen, H; Lindroos, L; Kangas, J; Vartiainen, T

    2000-09-01

    Extractable tannins were analysed by liquid chromatography-electrospray ionisation mass spectrometry in two oak species, North American white oak (Quercus alba) and European red oak (Quercus robur). They mainly included various glucose gallic and ellagic acid esters. The structures were partially determined, and they included grandinin/roburin E, castalagin/vescalagin, gallic acid, valoneic acid bilactone, monogalloyl glucose, digalloyl glucose, trigalloyl glucose, ellagic acid rhamnose, quercitrin and ellagic acid. PMID:10999626

  13. Ionisation and discharge in cloud-forming atmospheres of brown dwarfs and extrasolar planets

    NASA Astrophysics Data System (ADS)

    Helling, Ch; Rimmer, P. B.; Rodriguez-Barrera, I. M.; Wood, Kenneth; Robertson, G. B.; Stark, C. R.

    2016-07-01

    Brown dwarfs and giant gas extrasolar planets have cold atmospheres with rich chemical compositions from which mineral cloud particles form. Their properties, like particle sizes and material composition, vary with height, and the mineral cloud particles are charged due to triboelectric processes in such dynamic atmospheres. The dynamics of the atmospheric gas is driven by the irradiating host star and/or by the rotation of the objects that changes during its lifetime. Thermal gas ionisation in these ultra-cool but dense atmospheres allows electrostatic interactions and magnetic coupling of a substantial atmosphere volume. Combined with a strong magnetic field \\gg {{B}\\text{Earth}} , a chromosphere and aurorae might form as suggested by radio and x-ray observations of brown dwarfs. Non-equilibrium processes like cosmic ray ionisation and discharge processes in clouds will increase the local pool of free electrons in the gas. Cosmic rays and lighting discharges also alter the composition of the local atmospheric gas such that tracer molecules might be identified. Cosmic rays affect the atmosphere through air showers in a certain volume which was modelled with a 3D Monte Carlo radiative transfer code to be able to visualise their spacial extent. Given a certain degree of thermal ionisation of the atmospheric gas, we suggest that electron attachment to charge mineral cloud particles is too inefficient to cause an electrostatic disruption of the cloud particles. Cloud particles will therefore not be destroyed by Coulomb explosion for the local temperature in the collisional dominated brown dwarf and giant gas planet atmospheres. However, the cloud particles are destroyed electrostatically in regions with strong gas ionisation. The potential size of such cloud holes would, however, be too small and might occur too far inside the cloud to mimic the effect of, e.g. magnetic field induced star spots.

  14. A Carbon Nano Tube electron impact ionisation source for low-power, compact spacecraft mass spectrometers

    NASA Astrophysics Data System (ADS)

    Sheridan, S.; Bardwell, M. W.; Morse, A. D.; Morgan, G. H.

    2012-04-01

    A novel ionisation source which uses commercially available Carbon Nano Tube devices is demonstrated as a replacement for a filament based ionisation source in an ion trap mass spectrometer. The carbon nanotube ion source electron emission was characterised and exhibited typical emission of 30 ± 1.7 μA with an applied voltage differential of 300 V between the carbon nanotube tips and the extraction grid. The ion source was tested for longevity and operated under a condition of continuous emission for a period of 44 h; there was an observed reduction in emission current of 26.5% during operation. Spectra were generated by installing the ion source into a Finnigan Mat ITD700 ion trap mass spectrometer; the spectra recorded showed all of the characteristic m/z peaks from m/z 69 to m/z 219. Perfluorotributylamine spectra were collected and averaged contiguously for a period of 48 h with no significant signal loss or peak mass allocation shift. The low power requirements and low mass of this novel ionisation source are considered be of great value to future space missions where mass spectrometric technology will be employed.

  15. Examining Pre-Service Teachers' Use of Atomic Models in Explaining Subsequent Ionisation Energy Values

    NASA Astrophysics Data System (ADS)

    Wheeldon, Ruth

    2012-06-01

    Chemistry students' explanations of ionisation energy phenomena often involve a number of non-scientific or inappropriate ideas being used to form causality arguments. Research has attributed this to many science teachers using these ideas themselves (Tan and Taber, in J Chem Educ 86(5):623-629, 2009). This research extends this work by considering which atomic models are used in pre-service teachers' explanations and how that relates to the causality ideas expressed. Thirty-one pre-service teachers were interviewed. Each was asked to describe and explain four different atomic representations (Rutherford, Electron cloud micrograph, Bohr and Schrödinger types) in as much detail as they could. They also provided an explanation for the subsequent ionisation energy values for an oxygen atom and identified which representations were helpful in explaining the values. Significantly, when pre-service teachers only used Bohr type representations, they did not use repelling electron ideas in their explanations. However, arguments that were based on electron-electron repulsion used features from Schrödinger type atoms. These findings suggest that many pre-service teachers need to develop their atomic modelling skills so that they select and use models more expertly and that subsequent ionisation explanations offer a context in which to explore different atomic models' limitations and their deployment as explanatory resources.

  16. A liquid ionisation detector for digital radiography of therapeutic megavoltage photon beams.

    PubMed

    Meertens, H; van Herk, M; Weeda, J

    1985-04-01

    Experiments with an ionisation detector were performed in order to determine whether it was possible to obtain high energy photon beam images for radiotherapy treatment verification. A small prototype detector with a field of view of 78 mm X 78 mm and constructed from printed circuit boards was used. The imaging area was a matrix ionisation chamber, filled with air or liquid (2,2,4-trimethylpentane). A minicomputer was used to control the data acquisition electronics and to reconstruct and restore the images. The images were displayed on a viewing console for computed tomography images. The liquid filled detector with a front-rear board separation of 1.0 mm gave the best results. The spatial resolution was about 3.8 mm with a density resolution of 0.5% for a data acquisition time of 120 s. Comparison of the liquid detector images with corresponding metal screen-film detector images showed that the image qualities were the same. An important advantage of the ionisation detector image is that grey scale modification, sharpening and smoothing by digital processing can easily be performed. PMID:3923505

  17. Born total ionisation cross sections: An algebraic computing program using Maple

    NASA Astrophysics Data System (ADS)

    Bartlett, Philip L.; Stelbovics, Andris T.

    2003-08-01

    The software described in this paper uses the Maple algebraic computing environment to calculate an analytic form for the matrix element of the plane-wave Born approximation of the electron-impact ionisation of an atomic orbital, with arbitrary orbital and angular momentum quantum numbers. The atomic orbitals are approximated by Hartree-Fock Slater functions, and the ejected electron is modelled by a hydrogenic Coulomb wave, made orthogonal to all occupied orbitals of the target atom. Clenshaw-Curtis integration techniques are then used to calculate the total ionisation cross-section. For improved performance, the numerical integrations are performed using FORTRAN by automatically converting the analytic matrix element for each orbital into a FORTRAN subroutine. The results compare favourably with experimental data for a wide range of elements, including the transition metals, with excellent convergence at high energies. Program summaryTitle of program: BIX Catalogue identifier:ADRZ Program summary URL:http://www.cpc.cs.qub.ac.uk/cpc/summaries/ADRZ Program obtainable from:CPC Program Library, Queen's University of Belfast, N. Ireland Computers: Platform independent Operating systems: Tested on DEC Alpha Unix, Windows NT 4.0 and Windows XP Professional Edition Programming language used: Maple V Release 5.1 and FORTRAN 90 Memory required: 256 MB No. of processors used: 1 No. of bytes in distributed program, including test data, etc.:61754 Distributed format:tar gzip file Keywords: Born approximation, electron-impact ionisation cross-section, Maple, Hartree-Fock Nature of physical problem: Calculates the total electron impact ionisation cross-section for neutral and ionised atomic species using the first-Born approximation. The scattered electron is modelled by a plane wave, and the ejected electron is modelled by a hydrogenic Coulomb wave, which is made orthogonal to all occupied atomic orbitals, and the atomic orbitals are approximated by Hartree-Fock Slater

  18. Griffe cubitale d'origine lépreuse traitée par transfert tendineux de Lasso Zancolli: à propos d'un cas

    PubMed Central

    El Alaoui, Adil; Sbiyaa, Mouhcine; Bah, Aliou; Rabhi, Ilyas; mezzani, Amine; Marzouki, Amine; Boutayeb, Fawzi

    2015-01-01

    La lèpre est une maladie infectieuse due à une mycobactérie (M. Leprae, Bacille de Hansen, ou BH) dont le tropisme nerveux est destructeur pour les cellules de Schwann. La localisation préférentielle des neuropathies tronculaire secondaire à la lèpre restent dominé par les zones ou les troncs nerveux traversent les défilés ostéo-ligamentaires inextensibles comme le défilé rétro-épitrochléen ou passe le nerf ulnaire. De nombreux travaux ont été consacrés à la souffrance nerveuse secondaire à la lèpre et surtout l'atteinte du nerf ulnaire qui se manifeste par une griffe des doigts. Le traitement dans ce cas est palliatif et fait appel à plusieurs techniques décrites dans la littérature. Nous rapportons dans ce travail un cas de griffe cubitale chez un patient lépreux traité par transfert tendineux de Lasso Zancolli. PMID:26985277

  19. Comparison of low and high dose ionising radiation using topological analysis of gene coexpression networks

    PubMed Central

    2012-01-01

    Background The growing use of imaging procedures in medicine has raised concerns about exposure to low-dose ionising radiation (LDIR). While the disastrous effects of high dose ionising radiation (HDIR) is well documented, the detrimental effects of LDIR is not well understood and has been a topic of much debate. Since little is known about the effects of LDIR, various kinds of wet-lab and computational analyses are required to advance knowledge in this domain. In this paper we carry out an “upside-down pyramid” form of systems biology analysis of microarray data. We characterised the global genomic response following 10 cGy (low dose) and 100 cGy (high dose) doses of X-ray ionising radiation at four time points by analysing the topology of gene coexpression networks. This study includes a rich experimental design and state-of-the-art computational systems biology methods of analysis to study the differences in the transcriptional response of skin cells exposed to low and high doses of radiation. Results Using this method we found important genes that have been linked to immune response, cell survival and apoptosis. Furthermore, we also were able to identify genes such as BRCA1, ABCA1, TNFRSF1B, MLLT11 that have been associated with various types of cancers. We were also able to detect many genes known to be associated with various medical conditions. Conclusions Our method of applying network topological differences can aid in identifying the differences among similar (eg: radiation effect) yet very different biological conditions (eg: different dose and time) to generate testable hypotheses. This is the first study where a network level analysis was performed across two different radiation doses at various time points, thereby illustrating changes in the cellular response over time. PMID:22594378

  20. Design and performance of an ionisation chamber for the measurement of low alpha-activities

    NASA Astrophysics Data System (ADS)

    Hartmann, A.; Hutsch, J.; Krüger, F.; Sobiella, M.; Wilsenach, H.; Zuber, K.

    2016-04-01

    A new ionisation chamber for alpha-spectroscopy has been built from radio-pure materials for the purpose of investigating long lived alpha-decays. The measurement makes use of pulse shape analysis to discriminate between signal and background events. The design and performance of the chamber is described in this paper. A background rate of (10.9 ± 0.6) counts per day in the energy region of 1-9 MeV was achieved with a run period of 30.8 days. The background is dominantly produced by radon daughters.

  1. Characterisation of the muon beams for the Muon Ionisation Cooling Experiment

    SciTech Connect

    Adams, D.; et al.,

    2013-10-01

    A novel single-particle technique to measure emittance has been developed and used to characterise seventeen different muon beams for the Muon Ionisation Cooling Experiment (MICE). The muon beams, whose mean momenta vary from 171 to 281 MeV/c, have emittances of approximately 1.5--2.3 \\pi mm-rad horizontally and 0.6--1.0 \\pi mm-rad vertically, a horizontal dispersion of 90--190 mm and momentum spreads of about 25 MeV/c. There is reasonable agreement between the measured parameters of the beams and the results of simulations. The beams are found to meet the requirements of MICE.

  2. Forensic applications of desorption electrospray ionisation mass spectrometry (DESI-MS).

    PubMed

    Morelato, Marie; Beavis, Alison; Kirkbride, Paul; Roux, Claude

    2013-03-10

    Desorption electrospray ionisation mass spectrometry (DESI-MS) is an emerging analytical technique that enables in situ mass spectrometric analysis of specimens under ambient conditions. It has been successfully applied to a large range of forensically relevant materials. This review assesses and highlights forensic applications of DESI-MS including the analysis and detection of illicit drugs, explosives, chemical warfare agents, inks and documents, fingermarks, gunshot residues and drugs of abuse in urine and plasma specimens. The minimal specimen preparation required for analysis and the sensitivity of detection achieved offer great advantages, especially in the field of forensic science. PMID:23498998

  3. Estimation of useful yield in surface analysis using single photon ionisation

    NASA Astrophysics Data System (ADS)

    King, B. V.; Pellin, M. J.; Moore, J. F.; Veryovkin, I. V.; Savina, M. R.; Tripa, C. E.

    2003-01-01

    Secondary ion mass spectrometry (SIMS), laser sputter neutral mass spectrometry (SNMS) and laser desorption photoionisation (LDPI) have been used to investigate the desorption of molecules from self-assembled monolayers of phenylsulphides. LDPI, using an F 2 excimer laser to single photon ionise gave the lowest fragmentation. A useful yield greater than 0.5% was found for analysis of diphenyldisulphide self-assembled monolayers. It is shown that using a free electron laser to postionise will lead, in the future, to analysis of many atoms and molecules with useful yields approaching 30%.

  4. EVOLUTION OF THE IEC AND EN STANDARDS FOR INDIVIDUAL MONITORING OF IONISING RADIATION.

    PubMed

    Voytchev, M; Behrens, R; Ambrosi, P; Radev, R; Chiaro, P

    2016-09-01

    This article presents the evolution of the International Electrotechnical Commission (IEC) and the European standards for individual monitoring of ionising radiation issued, respectively, from the committees IEC/Sub Committee 45B and European Committee for Electro-technical Standardization/Technical Committee 45B 'Radiation protection instrumentation'. Standards for passive individual photon and beta dosimetry systems as well as those for active individual monitors are discussed. A neutron ambient dose equivalent (rate) meter standard and a technical report concerning the determination of uncertainty in measurement are also covered. PMID:26443545

  5. Skin dose measurements using radiochromic films, TLDS and ionisation chamber and comparison with Monte Carlo simulation.

    PubMed

    Alashrah, Saleh; Kandaiya, Sivamany; Maalej, Nabil; El-Taher, A

    2014-12-01

    Estimation of the surface dose is very important for patients undergoing radiation therapy. The purpose of this study is to investigate the dose at the surface of a water phantom at a depth of 0.007 cm as recommended by the International Commission on Radiological Protection and International Commission on Radiation Units and Measurement with radiochromic films (RFs), thermoluminescent dosemeters and an ionisation chamber in a 6-MV photon beam. The results were compared with the theoretical calculation using Monte Carlo (MC) simulation software (MCNP5, BEAMnrc and DOSXYZnrc). The RF was calibrated by placing the films at a depth of maximum dose (d(max)) in a solid water phantom and exposing it to doses from 0 to 500 cGy. The films were scanned using a transmission high-resolution HP scanner. The optical density of the film was obtained from the red component of the RGB images using ImageJ software. The per cent surface dose (PSD) and percentage depth dose (PDD) curve were obtained by placing film pieces at the surface and at different depths in the solid water phantom. TLDs were placed at a depth of 10 cm in a solid water phantom for calibration. Then the TLDs were placed at different depths in the water phantom and were exposed to obtain the PDD. The obtained PSD and PDD values were compared with those obtained using a cylindrical ionisation chamber. The PSD was also determined using Monte Carlo simulation of a LINAC 6-MV photon beam. The extrapolation method was used to determine the PSD for all measurements. The PSD was 15.0±3.6% for RF. The TLD measurement of the PSD was 16.0±5.0%. The (0.6 cm(3)) cylindrical ionisation chamber measurement of the PSD was 50.0±3.0%. The theoretical calculation using MCNP5 and DOSXYZnrc yielded a PSD of 15.0±2.0% and 15.7±2.2%. In this study, good agreement between PSD measurements was observed using RF and TLDs with the Monte Carlo calculation. However, the cylindrical chamber measurement yielded an overestimate of the PSD

  6. Investigating ionisation cluster size distribution due to sub-1 keV electrons in view of Heisenberg's Uncertainty

    NASA Astrophysics Data System (ADS)

    Li, B.; Palmans, H.; Hao, L.; Nisbet, A.

    2015-09-01

    As the wavelengths of low energy electrons become comparable with the length scale of the mean ionisation step size, each event particle should be treated with care as the condition outlined in Heisenberg's uncertainty principle (HUP) should also be satisfied. Within this quantum-classical regime, spatial delocalisations of individual ionisation event sites that are generated outside the target region are calculated, and particular attention is given to the validity of using classical transport methods in simulations of nanodosimetric parameters such as mean cluster size, first and second moments, variance and cumulative frequency of ionisation cluster-size probability distributions. This paper presents the comparison between conventionally calculated nanodosimetric quantities and the ones where interacting particles are treated semi-classically with spatial uncertainties satisfied by HUP. The simulated primary charged particles are electrons of energies between 100 eV and 1 keV in DNA equivalent target aqueous water volumes using GEANT4-DNA.

  7. Ionisation effects on the permeation of pharmaceutical compounds through silicone membrane.

    PubMed

    Waters, L J; Bhuiyan, A K M M H

    2016-05-01

    Silicone membrane is frequently used as an in vitro skin mimic whereby experiments incorporate a range of buffered media which may vary in pH. As a consequence of such variability in pH there is a corresponding variability in the degree of ionisation which in turn, could influence permeation through the mainly hydrophobic-rich membrane structure. This study reports the effect of pH on the permeation of five model compounds (benzoic acid, benzotriazole, ibuprofen, ketoprofen and lidocaine). For the five compounds analysed, each at three distinct percentages of ionisation, it was found that the greater extent of permeation was always for the more 'neutral', i.e. more greatly unionised, species rather than the anionic or cationic species. These findings fit with the theory that the hydrophobic membrane encourages permeation of 'lipid-like' structures, i.e. the more unionised form of compounds. However, results obtained with an Inverse Gas Chromatography Surface Energy Analyser (iGC SEA) indicate the membrane surface to be an electron dense environment. In the knowledge that unionised forms of compounds permeate (rather than the charged species) this negatively charged surface was not anticipated, i.e. the basic membrane surface did not appear to affect permeation. PMID:26896663

  8. High throughput volatile fatty acid skin metabolite profiling by thermal desorption secondary electrospray ionisation mass spectrometry.

    PubMed

    Martin, Helen J; Reynolds, James C; Riazanskaia, Svetlana; Thomas, C L Paul

    2014-09-01

    The non-invasive nature of volatile organic compound (VOC) sampling from skin makes this a priority in the development of new screening and diagnostic assays. Evaluation of recent literature highlights the tension between the analytical utility of ambient ionisation approaches for skin profiling and the practicality of undertaking larger campaigns (higher statistical power), or undertaking research in remote locations. This study describes how VOC may be sampled from skin and recovered from a polydimethylsilicone sampling coupon and analysed by thermal desorption (TD) interfaced to secondary electrospray ionisation (SESI) time-of-flight mass spectrometry (MS) for the high throughput screening of volatile fatty acids (VFAs) from human skin. Analysis times were reduced by 79% compared to gas chromatography-mass spectrometry methods (GC-MS) and limits of detection in the range 300 to 900 pg cm(-2) for VFA skin concentrations were obtained. Using body odour as a surrogate model for clinical testing 10 Filipino participants, 5 high and 5 low odour, were sampled in Manilla and the samples returned to the UK and screened by TD-SESI-MS and TD-GC-MS for malodour precursors with greater than >95% agreement between the two analytical techniques. Eight additional VFAs were also identified by both techniques with chains 4 to 15 carbons long being observed. TD-SESI-MS appears to have significant potential for the high throughput targeted screening of volatile biomarkers in human skin. PMID:24992564

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

    PubMed

    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

  10. Adaptive response to ionising radiation induced by cadmium in zebrafish embryos.

    PubMed

    Choi, V W Y; Ng, C Y P; Kong, M K Y; Cheng, S H; Yu, K N

    2013-03-01

    An adaptive response is a biological response where the exposure of cells or animals to a low priming exposure induces mechanisms that protect the cells or animals against the detrimental effects of a subsequent larger challenging exposure. In realistic environmental situations, living organisms can be exposed to a mixture of stressors, and the resultant effects due to such exposures are referred to as multiple stressor effects. In the present work we demonstrated, via quantification of apoptosis in the embryos, that embryos of the zebrafish (Danio rerio) subjected to a priming exposure provided by one environmental stressor (cadmium in micromolar concentrations) could undergo an adaptive response against a subsequent challenging exposure provided by another environmental stressor (alpha particles). We concluded that zebrafish embryos treated with 1 to 10 μM Cd at 5 h postfertilisation (hpf) for both 1 and 5 h could undergo an adaptive response against subsequent ~4.4 mGy alpha-particle irradiation at 10 hpf, which could be interpreted as an antagonistic multiple stressor effect between Cd and ionising radiation. The zebrafish has become a popular vertebrate model for studying the in vivo response to ionising radiation. As such, our results suggested that multiple stressor effects should be carefully considered for human radiation risk assessment since the risk may be perturbed by another environmental stressor such as a heavy metal. PMID:23296313

  11. High-resolution laser spectroscopy with the Collinear Resonance Ionisation Spectroscopy (CRIS) experiment at CERN-ISOLDE

    NASA Astrophysics Data System (ADS)

    Cocolios, T. E.; de Groote, R. P.; Billowes, J.; Bissell, M. L.; Budinčević, I.; Day Goodacre, T.; Farooq-Smith, G. J.; Fedosseev, V. N.; Flanagan, K. T.; Franchoo, S.; Garcia Ruiz, R. F.; Gins, W.; Heylen, H.; Kron, T.; Li, R.; Lynch, K. M.; Marsh, B. A.; Neyens, G.; Rossel, R. E.; Rothe, S.; Smith, A. J.; Stroke, H. H.; Wendt, K. D. A.; Wilkins, S. G.; Yang, X.

    2016-06-01

    The Collinear Resonance Ionisation Spectroscopy (CRIS) experiment at CERN has achieved high-resolution resonance ionisation laser spectroscopy with a full width at half maximum linewidth of 20(1) MHz for 219,221 Fr, and has measured isotopes as short lived as 5 ms with 214 Fr. This development allows for greater precision in the study of hyperfine structures and isotope shifts, as well as a higher selectivity of single-isotope, even single-isomer, beams. These achievements are linked with the development of a new laser laboratory and new data-acquisition systems.

  12. Correlation of the ionisation response at selected points of IC sensitive regions with SEE sensitivity parameters under pulsed laser irradiation

    SciTech Connect

    Gordienko, A V; Mavritskii, O B; Egorov, A N; Pechenkin, A A; Savchenkov, D V

    2014-12-31

    The statistics of the ionisation response amplitude measured at selected points and their surroundings within sensitive regions of integrated circuits (ICs) under focused femtosecond laser irradiation is obtained for samples chosen from large batches of two types of ICs. A correlation between these data and the results of full-chip scanning is found for each type. The criteria for express validation of IC single-event effect (SEE) hardness based on ionisation response measurements at selected points are discussed. (laser applications and other topics in quantum electronics)

  13. Effects of ionised or chelated water-soluble mineral mixture supplementation on growth performance, nutrient digestibility, blood characteristics, meat quality and intestinal microbiota in broilers.

    PubMed

    Upadhaya, S D; Lee, B R; Kim, I H

    2016-04-01

    An experiment was conducted to study the effects of dietary supplementation of water-soluble ionised or chelated mineral mixture on growth performance, nutrient digestibility, blood characteristics, relative organ weight, meat quality and excreta microflora in broilers. A total of 408 Arbor Acres broilers (17 birds in 8 replicate pens) were randomly allocated into one of the following three treatments: (1) Control/basal diet (CON), (2) T1 (basal diet + 0.5% ionised mineral mixture solution, pH 3.0) and (3) T2 (basal diet + 0.5% chelated mineral mixture solution, pH 3.0). The body weight gain was greater and feed conversion ratio was lower in broilers supplemented with ionised or chelated mineral liquid complex compared to CON during the grower and overall phase of the experiment. No significant effect in the concentration of Ca and P in the blood was observed in birds supplemented with ionised or chelated mineral mixture solution. No adverse effects were observed in organ weight and meat quality with ionised or chelated mineral mixture supplementation. Regarding intestinal microbiota counts there was a reduction of Escherichia coli counts in the small intestine in ionised mineral supplemented birds. In the large intestine, E. coli as well as Salmonella populations were reduced in ionised mineral supplemented birds. In conclusion, ionised or chelated minerals have partial positive effects in improving growth performance and reducing pathogenic bacteria load in the gastro-intestinal tract. PMID:27088481

  14. Multidisciplinary approach to assess the sensitivity of dwarf tomato plants to low-LET ionising radiation

    NASA Astrophysics Data System (ADS)

    De Micco, Veronica; De Pascale, Stefania; Aronne, Giovanna; Paradiso, Roberta; Vitaglione, Paola; Turano, Mimmo; Arena, Carmen

    Ionising radiation, acting alone or in interaction with microgravity and other environmental constraints, may affect plant at molecular, morpho-structural and physiological level. The intensity of the plant’s response depends on the properties of radiation and on the features of the plant itself. Indeed, different species are characterised by different susceptibility to radiation which may change during the life course. The aim of this research was to study the radiosensitivity to low-LET ionising radiation of plants of dwarf tomato (Solanum lycopersicum L. ‘Microtom’) at two phenological phases (vegetative and reproductive), within the purpose of analysing plants for consideration as candidates for Bioregenerative Life Support Systems (BLSS) in Space. To pursue this objective, plants of the cultivar Microtom were irradiated with different doses of X-rays either at the stage of the second true leaf (VP - vegetative phase) or when at least one flower was blossomed (RP - reproductive phase). Plant’s response to ionising radiation was assessed through a multidisciplinary approach combining genetic analyses, ecophysiological measurements, morpho-anatomical characterisation of leaves and fruits, nutritional analyses of fruits. Growth, molecular and morpho-functional traits were measured during plant development up to fruiting in both VP and RP plant groups, and compared with non-irradiated control plants. Plant growth was monitored weekly recording parameters such as plant height, number of leaves, leaf area, flowering and fruiting rate. Potential DNA alterations were explored through Random Amplified Polymorphic DNA (RAPD) technique. The efficiency of the photosynthetic apparatus was evaluated by determining photosynthetic pigment composition, photochemistry and leaf gas exchanges. Leaf and fruit structure were analysed through light and epi-fluorescence microscopy. Leaf anatomical traits related to photosynthetic efficiency, and to structural radioprotection

  15. Evidence For The Tongue of Ionisation In The Winter Dayside Ionosphere Over Svalbard

    NASA Astrophysics Data System (ADS)

    Pryse, S. E.; Sims, R. W.; Moen, J.

    Results are presented from a multi-instrument investigation of the dayside ionosphere at high latitudes, under conditions of Bz<0, that provide evidence for the tongue- of-ionisation (TOI) in winter over Svalbard. The TOI, transporting photoionisation from sub-auroral latitudes into the polar cap, has been identified in three successive tomography images at latitudes on the equatorward edge of the auroral region in the post-noon sector. Simultaneous observations by the ESR incoherent scatter radar re- veal cold plasma of increased density in the vicinity of the throat region where the TOI enters the polar cap. Supporting evidence for the feature is provided by optical emissions measured by meridian scanning photometers, together with plasma drift and particle observations from DMSP satellites. The observations are discussed in light of earlier modelling studies of the TOI.

  16. The risk of childhood leukaemia following exposure to ionising radiation--a review.

    PubMed

    Wakeford, Richard

    2013-03-01

    Since the early years of follow-up of the Japanese atomic-bomb survivors, it has been apparent that childhood leukaemia has a particular sensitivity to induction by ionising radiation, the excess relative risk (ERR) being expressed as a temporal wave with time since exposure. This pattern has been generally confirmed by studies of children treated with radiotherapy. Case-control studies of childhood leukaemia and antenatal exposure to diagnostic x-rays, a recent large cohort study of leukaemia following CT examinations of young people, and a recent large case-control study of natural background γ-radiation and childhood leukaemia have found evidence of raised risks following low-level exposure. These findings indicate that an ERR/Sv for childhood leukaemia of ~50, which may be derived from risk models based upon the Japanese atomic-bomb survivors, is broadly applicable to low dose or low dose-rate exposure circumstances. PMID:23296257

  17. Desorption electrospray ionisation mass spectrometry and tandem mass spectrometry of low molecular weight synthetic polymers.

    PubMed

    Jackson, Anthony T; Williams, Jonathan P; Scrivens, James H

    2006-01-01

    A range of low molecular weight synthetic polymers has been characterised by means of desorption electrospray ionisation (DESI) combined with both mass spectrometry (MS) and tandem mass spectrometry (MS/MS). Accurate mass experiments were used to aid the structural determination of some of the oligomeric materials. The polymers analysed were poly(ethylene glycol) (PEG), polypropylene glycol (PPG), poly(methyl methacrylate) (PMMA) and poly(alpha-methyl styrene). An application of the technique for characterisation of a polymer used as part of an active ingredient in a pharmaceutical tablet is described. The mass spectra and tandem mass spectra of all of the polymers were obtained in seconds, indicating the sensitivity of the technique. PMID:16912984

  18. The perturbation correction factor of ionisation chambers in beta-radiation fields.

    PubMed

    Böhm, J

    1980-01-01

    In determining the absorbed dose in a solid medium by means of gas-filled ionisation chambers, the perturbation of the radiation field by the chamber needs to be taken into account. So far, an appropriate correction factor has neither been calculated nor measured for beta-radiation. This work describes its experimental determination for an extrapolation chamber and beta-radiation fields of 147Pm, 204Tl, and 90Sr + 90Y. The results show that the correction factor may be assumed to be the product of a shield factor and a scatter factor the magnitudes of which depend on the chamber geometry and the radiation field. The change of the perturbation correction factor with phantom depth is important for the measurement of depth dose curves. This is demonstrated by an example. PMID:7360793

  19. Laser Ablation/Ionisation Mass Spectrometry: Sensitive and Quantitative Chemical Depth Profiling of Solid Materials.

    PubMed

    Riedo, Andreas; Grimaudo, Valentine; Moreno-García, Pavel; Neuland, Maike B; Tulej, Marek; Broekmann, Peter; Wurz, Peter

    2016-01-01

    Direct quantitative and sensitive chemical analysis of solid materials with high spatial resolution, both in lateral and vertical direction is of high importance in various fields of analytical research, ranging from in situ space research to the semiconductor industry. Accurate knowledge of the chemical composition of solid materials allows a better understanding of physical and chemical processes that formed/altered the material and allows e.g. to further improve these processes. So far, state-of-the-art techniques such as SIMS, LA-ICP-MS or GD-MS have been applied for chemical analyses in these fields of research. In this report we review the current measurement capability and the applicability of our Laser Ablation/Ionisation Mass Spectrometer (instrument name LMS) for the chemical analysis of solids with high spatial resolution. The most recent chemical analyses conducted on various solid materials, including e.g. alloys, fossils and meteorites are discussed. PMID:27131112

  20. Preparation of (K:Eu) NaSO4 phosphor for lyoluminescence dosimetry of ionising radiation.

    PubMed

    Dhoble, S J

    2002-01-01

    Gamma ray dosimetry using lyoluminescence is a low cost and simple system. As sulphate based phosphors are used for TL radiation dosimetry they therefore seem to be a promising material for LL gamma ray dosimetry. A study on LL properties of Eu activated KNaSO4 and K3Na(SO4)2 gamma irradiated materials is reported. Eu doped KNaSO4 shows maximum LL yield in the above system. It shows a linear response from 0.06 to 10 C.kg(-1) and there is not much fading of LL intensity, indicating the phosphor to be suitable as a lyoluminescence dosimetry phosphor of ionising radiation. The doped Eu ion acts as an activator and thus enhances the LL intensity of the phosphor. PMID:12382879

  1. Chemical profile of mango (Mangifera indica L.) using electrospray ionisation mass spectrometry (ESI-MS).

    PubMed

    Oliveira, Bruno G; Costa, Helber B; Ventura, José A; Kondratyuk, Tamara P; Barroso, Maria E S; Correia, Radigya M; Pimentel, Elisângela F; Pinto, Fernanda E; Endringer, Denise C; Romão, Wanderson

    2016-08-01

    Mangifera indica L., mango fruit, is consumed as a dietary supplement with purported health benefits; it is widely used in the food industry. Herein, the chemical profile of the Ubá mango at four distinct maturation stages was evaluated during the process of growth and maturity using negative-ion mode electrospray ionisation Fourier transform ion cyclotron resonance mass spectrometry (ESI(-)FT-ICR MS) and physicochemical characterisation analysis (total titratable acidity (TA), total soluble solids (TSS), TSS/TA ratio, and total polyphenolic content). Primary (organic acids and sugars) and secondary metabolites (polyphenolic compounds) were mostly identified in the third maturation stage, thus indicating the best stage for harvesting and consuming the fruit. In addition, the potential cancer chemoprevention of the secondary metabolites (phenolic extracts obtained from mango samples) was evaluated using the induction of quinone reductase activity, concluding that fruit polyphenols have the potential for cancer chemoprevention. PMID:26988473

  2. Carrier-envelope phase effects in few-cycle ionisation of atomic hydrogen

    NASA Astrophysics Data System (ADS)

    Kielpinski, David; Wallace, W. C.; Pullen, M. G.; Ghafur, O.; Laban, D. E.; Palmer, A. J.; Hanne, G. F.; Grum-Grzhimailo, A. N.; Bartschat, K.; Ivanov, I. A.; Kheifets, A. S.; Tong, X.-M.; Quiney, H. M.; Litvinyuk, I. V.; Sang, R. T.

    2012-06-01

    The control of strong-field photoionization with laser carrier-envelope phase (CEP) is the key enabling technique for attosecond science. Currently, quantitatively accurate ab initio simulations of this process can only be carried out for atomic hydrogen. We have observed CEP effects in the above-threshold ionisation of atomic hydrogen for the first time. The modulation due to CEP is mapped over a wide range of laser intensity and electron energy. The data is compared with ab initio simulations for the time dependent Schr"odinger equation carried out using three separate methodologies, as well as a semi-ab initio simulation method. We find reasonable agreement between experiment and all simulations over the entire sampled parameter space. Our results point the way toward accurate calibration of absolute laser CEP by means of the uniquely calculable hydrogen system.

  3. Application of Lithium Attachment Mass Spectrometry for Knudsen Evaporation and Chemical Ionisation Mass Spectrometry (KEMS, CIMS)

    NASA Astrophysics Data System (ADS)

    Bannan, T.; Booth, M.; Benyezzar, M.; Bacak, A.; Alfarra, M. R. R.; Topping, D. O.; Percival, C.

    2015-12-01

    Lithium ion attachment mass spectrometry provides a non-specific, non-fragmenting and sensitive method for detection of volatile species in the gas phase. The design, manufacture, and results from lithium ion attachment ionisation sources for two mass spectrometry systems are presented. Trace gas analysis is investigated using a modified Chemical Ionization Mass Spectrometer (CIMS) and vapour pressure (VP) measurements using a modified Knudsen Effusion Mass Spectrometer (KEMS) are presented. The Li+ modified CIMS provided limits of detection of 4 ppt for acetone, 0.2 ppt for formic acid, 15 ppt for nitric acid and 120 ppt from ammonia. Despite improvements, the problem of burnout remained persistent. The Li+ CIMS would unlikely be suitable for field or aircraft work, but could be appropriate for certain lab applications. The KEMS currently utilizes an electron impact (EI) ionisation source which provides a highly sensitive source, with the drawback of fragmentation of ionized molecules (Booth et al., 2009). Using Li+ KEMS the VP of samples can be measured without fragmentation and can therefore be used to identify VPs of individual components in mixtures. The validity of using Li+ for determining the VP of mixtures was tested by making single component VP measurements, which showed good agreement with EI measurements of Poly ethylene glycol (PEG) 3 and PEG 4, both when individually measured and when mixed. The Li+ KEMS was then used to investigate a system of atmospheric relevance, α-pinene secondary organic aerosol, generated in a reaction chamber (Alfarra et al., 2012). The VPs of the individual components from this generated sample are within the range we expect for compounds capable of partitioning between the particle and gas phase of an aerosol (0.1-10-5 Pa). Li+ source has a calculated sensitivity approximately 75 times less than that of EI, but the lack of fragmentation using the Li+ source is a significant advantage.

  4. Application of Lithium Attachment Mass Spectrometry for Knudsen Evaporation and Chemical Ionisation Mass Spectrometry (KEMS, CIMS)

    NASA Astrophysics Data System (ADS)

    Bannan, Thomas; Booth, A. Murray; Alfarra, Rami; Bacak, Asan; Pericval, Carl

    2016-04-01

    Lithium ion attachment mass spectrometry provides a non-specific, non-fragmenting and sensitive method for detection of volatile species in the gas phase. The design, manufacture, and results from lithium ion attachment ionisation sources for two mass spectrometry systems are presented. Trace gas analysis is investigated using a modified Chemical Ionization Mass Spectrometer (CIMS) and vapour pressure (VP) measurements using a modified Knudsen Effusion Mass Spectrometer (KEMS) are presented. The Li+ modified CIMS provided limits of detection of 4 ppt for acetone, 0.2 ppt for formic acid, 15 ppt for nitric acid and 120 ppt from ammonia. Despite improvements, the problem of burnout remained persistent. The Li+ CIMS would unlikely be suitable for field or aircraft work, but could be appropriate for certain lab applications. The KEMS currently utilizes an electron impact (EI) ionisation source which provides a highly sensitive source, with the drawback of fragmentation of ionized molecules (Booth et al., 2009). Using Li+ KEMS the VP of samples can be measured without fragmentation and can therefore be used to identify VPs of individual components in mixtures. The validity of using Li+ for determining the VP of mixtures was tested by making single component VP measurements, which showed good agreement with EI measurements of Poly ethylene glycol (PEG) 3 and PEG 4, both when individually measured and when mixed. The Li+ KEMS was then used to investigate a system of atmospheric relevance, α-pinene secondary organic aerosol, generated in a reaction chamber (Alfarra et al., 2012). The VPs of the individual components from this generated sample are within the range we expect for compounds capable of partitioning between the particle and gas phase of an aerosol (0.1-10-5 Pa). Li+ source has a calculated sensitivity approximately 75 times less than that of EI, but the lack of fragmentation using the Li+ source is a significant advantage.

  5. Simultaneous determination of volatile and non-volatile nitrosamines in processed meat products by liquid chromatography tandem mass spectrometry using atmospheric pressure chemical ionisation and electrospray ionisation.

    PubMed

    Herrmann, S S; Duedahl-Olesen, L; Granby, K

    2014-02-21

    A sensitive, selective and generic method has been developed for the simultaneous determination of the contents (μgkg(-1) range) of both volatile nitrosamines (VNA) and non-volatile nitrosamines (NVNA) in processed meat products. The extraction procedure only requires basic laboratory equipment and a small volume of organic solvent. Separation and quantification were performed by the developed LC-(APCI/ESI)MS/MS method. The method was validated using spiked samples of three different processed meat products. Satisfactory recoveries (50-130%) and precisions (2-23%) were obtained for eight VNA and six NVNAs with LODs generally between 0.2 and 1μgkg(-1), though for a few analyte/matrix combinations higher LODs were obtained (3 to 18μgkg(-1)). The validation results show that results obtained for one meat product is not always valid for other meat products. We were not able to obtain satisfactory results for N-nitrosohydroxyproline (NHPRO), N-nitrosodibenzylamine (NDBzA) and N-nitrosodiphenylamine (NDPhA). Application of the APCI interface improved the sensitivity of the method, because of less matrix interference, and gave the method a wider scope, as some NAs were ionisable only by APCI. However, it was only possible to ionize N-nitroso-thiazolidine-4-carboxylic acid (NTCA) and N-nitroso-2-methyl-thiazolidine-4-carboxylic acid (NMTCA) by ESI. The validated method was applied for the analysis of processed meat products and contents of N-nitrosodimethylamine (NDMA), N-nitrosopyrrolidine (NPYR), N-nitrosomethylaniline (NMA), N-nitrosoproline (NPRO), NTCA, and NMTCA were found in one or several nitrite cured meat products, whereas none were detected in non-nitrite cured bacon. PMID:24468241

  6. The use of particle beam mass spectrometry for the measurement of impurities in a nabumetone drug substance, not easily amenable to atmospheric pressure ionisation techniques.

    PubMed

    Wolff, J C; Hawtin, P N; Monté, S; Balogh, M; Jones, T

    2001-01-01

    Liquid chromatography/particle beam mass spectrometry (LC/PB-MS) was used for the structural elucidation of some impurities in nabumetone as this compound poorly ionises by atmospheric pressure ionisation (API) techniques. PB-MS was optimised for nabumetone and a sensitivity study was carried out. To obtain full scan electron ionisation spectra a minimum of 100 ng of compound on column was needed. By using 20 mg/mL solutions of nabumetone, impurities at levels of about 250 ppm mass fraction relative to nabumetone could be detected. Results were compared with LC/API-MS and previous GC/MS. PMID:11223957

  7. High-performance liquid chromatographic, capillary electrophoretic and capillary electrophoretic-electrospray ionisation mass spectrometric analysis of selected alkaloid groups.

    PubMed

    Stöckigt, Joachim; Sheludk, Yuri; Unger, Matthias; Gerasimenko, Irina; Warzecha, Heribert; Stöckigt, Detlef

    2002-08-16

    Systems for efficient separation of selected alkaloid groups by high performance liquid chromatography (HPLC), capillary electrophoresis (CE) and capillary electrophoresis coupled with electrospray ionisation mass spectrometry (CE-ESI-MS) are described. The optimized HPLC system was applied for the separation of 23 standard indole alkaloids as well as for qualitative and quantitative analyses of crude alkaloid extracts of Rauvolfia serpentina X Rhazya stricta hybrid cell cultures. The developed conditions for CE analysis proved to be efficient for separation of mixtures of standard indole and beta-carboline alkaloids. The described buffer system is also applicable in the combination of CE with electrospray ionisation mass spectrometry. This analytical technique allowed the separation and identification of components of standard indole alkaloid mixture as well as crude extracts of R. serpentina roots, R. serpentina cell suspension cultures and cortex of Aspidosperma quebracho-blanco. The influence of buffer composition and analyte structures on separation is discussed. PMID:12219932

  8. Investigation of the ionisation density dependence of the glow curve characteristics of LIF:MG,TI (TLD-100)

    PubMed Central

    Horowitz, Y. S.; Horowitz, A.; Oster, L.; Marino, S.; Datz, H.; Margaliot, M.

    2008-01-01

    The dependence of the shape of the glow curve of LiF:Mg,Ti (TLD-100) on ionisation density was investigated using irradiation with 90Sr/90Y beta rays, 60 and 250 kVp X rays, various heavy-charged particles and 0.2 and 14 MeV neutrons. Special attention is focused on the properties of high-temperature thermoluminescence; specifically, the behaviour of the high-temperature ratio (HTR) of Peaks 7 and 8 as a function of batch and annealing protocol. The correlation of Peaks 7 and 8 with average linear-energy-transfer (LET) is also investigated. The HTR of Peak 7 is found to be independent of LET for values of LET approximately >30 keV µm−1. The behaviour of the HTR of Peak 8 with LET is observed to be erratic, which suggests that applications using the HTR should separate the contributions of Peaks 7 and 8 using computerised glow curve deconvolution. The behaviour of the HTR following neutron irradiation is complex and not fully understood. The shape of composite Peak 5 is observed to be broader following high ionisation alpha particle irradiation, suggesting that the combined use of the HTR and the shape of Peak 5 could lead to improved ionisation density discrimination for particles of high LET. PMID:18667402

  9. Matrix-free mass spectrometric imaging using laser desorption ionisation Fourier transform ion cyclotron resonance mass spectrometry.

    PubMed

    Goodwin, Richard J A; Pitt, Andrew R; Harrison, David; Weidt, Stefan K; Langridge-Smith, Pat R R; Barrett, Michael P; Logan Mackay, C

    2011-04-15

    Mass spectrometry imaging (MSI) is a powerful tool in metabolomics and proteomics for the spatial localization and identification of pharmaceuticals, metabolites, lipids, peptides and proteins in biological tissues. However, sample preparation remains a crucial variable in obtaining the most accurate distributions. Common washing steps used to remove salts, and solvent-based matrix application, allow analyte spreading to occur. Solvent-free matrix applications can reduce this risk, but increase the possibility of ionisation bias due to matrix adhesion to tissue sections. We report here the use of matrix-free MSI using laser desorption ionisation performed on a 12 T Fourier transform ion cyclotron resonance (FTICR) mass spectrometer. We used unprocessed tissue with no post-processing following thaw-mounting on matrix-assisted laser desorption ionisation (MALDI) indium-tin oxide (ITO) target plates. The identification and distribution of a range of phospholipids in mouse brain and kidney sections are presented and compared with previously published MALDI time-of-flight (TOF) MSI distributions. PMID:21416534

  10. Formation of 2-propanol in condensed molecular films of acetaldehyde following electron impact ionisation-induced proton transfer*

    NASA Astrophysics Data System (ADS)

    Borrmann, Tobias; Swiderek, Petra

    2016-06-01

    Experimental studies on thin condensed layers of acetaldehyde have previously revealed that electron exposure at an energy above the ionisation threshold leads to formation of 2-propanol. However, the mechanism of this reaction remained unclear. Therefore, a computational approach is used to explore the electron-induced reactions of acetaldehyde yielding 2-propanol. Starting from hydrogen-bonded dimers of acetaldehyde we show that the initial ionisation event triggers proton transfer between the two acetaldehyde moieties resulting in a hydrogen-bonded complex of a [OCCH3] radical and a protonated acetaldehyde cation. Given an excess energy of up to 0.75 eV and a favourable arrangement, a methyl radical released upon dissociation of the CC bond within the [OCCH3] radical can migrate to the carbonyl carbon of the protonated acetaldehyde cation. This produces a 2-propanol radical cation and CO. Neutral 2-propanol is then obtained by recombination with a second electron. A mechanism involving ionisation-driven proton transfer is thus proposed as pathway to the formation of 2-propanol during electron exposure of condensed layers of acetaldehyde.

  11. Genotoxicity in earthworm after combined treatment of ionising radiation and mercury.

    PubMed

    Ryu, Tae Ho; An, Kwang-Guk; Kim, Jin Kyu

    2014-06-01

    This study was performed to investigate the acute genotoxic effects of mercury and radiation on earthworms (Eisenia fetida). The levels of DNA damage and the repair kinetics in the coelomocytes of E. fetida treated with mercuric chloride (HgCl₂) and ionising radiation (gamma rays) were analysed by means of the comet assay. For detection of DNA damage and repair, E. fetida was exposed to HgCl₂ (0-160 mg kg(-1)) and irradiated with gamma rays (0-50 Gy) in vivo. The increase in DNA damage depended on the concentration of mercury or dose of radiation. The results showed that the more the oxidative stress induced by mercury and radiation the longer the repair time that was required. When a combination of HgCl₂ and gamma rays was applied, the cell damage was much higher than those treated with HgCl₂ or radiation alone, which indicated that the genotoxic effects were increased after the combined treatment of mercury and radiation. PMID:24870361

  12. Resolving Ionisation and Metallicity on Parsec Scales Across Primordial Analogues with HST-WFC3

    NASA Astrophysics Data System (ADS)

    James, B. L.; Auger, M.; Calzetti, D.; Kewley, L.; Aloisi, A.; Pettini, M.; Trussler, J.

    2016-06-01

    Nearby Blue Compact Dwarf (BCD) galaxies are excellent laboratories for conducting detailed spatially resolved spectroscopic analyses of star-formation (SF), feedback, and chemical evolution in relatively pristine, low-metallicity environments analogous to those thought to exist in the early Universe. In this talk I will show a new, extensive dataset of narrow-band HST-WFC3 imaging where I essentially use HST as a high-spatial-resolution IFU to map six major emission lines in unprecedented detail, including HeII emission from WR stars. In this pioneering study, I spatially resolve diagnostic line ratios on sub-pc scales in two BCDs and deduce which ionisation mechanisms (e.g. shocks and/or photoionisation) are at work and assess their role in shaping the global galaxy properties. Moreover, I will present the first 'metallicity image' of a star-forming galaxy, revealing inhomogeneities on scales as small as <50~pc. This work not only demonstrates the benefits of high-resolution spatially-resolved observations in assessing the effects of feedback mechanisms and accurate chemical abundances, but also the limitations of emission line diagnostic tools which can break down on scales smaller than a H II region. Both aspects are especially relevant as we enter the era of extremely large telescopes, when observing structure on ˜~10~pc scales will no longer be limited to the local universe.

  13. Investigating the degradation of the sympathomimetic drug phenylephrine by electrospray ionisation-mass spectrometry.

    PubMed

    Trommer, Hagen; Raith, Klaus; Neubert, Reinhard H H

    2010-06-01

    The frequently used sympathomimetic drug phenylephrine has been studied by electrospray ionisation-mass spectrometry. The stability of the adrenoceptor agonist was examined by investigations of the pharmaceutically used salts phenylephrine hydrochloride and phenylephrine bitartrate. Photostability has been studied by use of an irradiation equipment emitting a solar radiation spectrum. The experiments were carried out by analysis of aqueous drug solutions before and after irradiation treatment. The phenylephrine derivative with unsaturated side chain originating from the drug by loss of one water molecule has been detected as the major degradation product of both phenylephrine salts the hydrochloride and the bitartrate. Further degradation and oxidation products were detectable already in the full scan mode demonstrating a low stability of the drug. Tandem mass spectrometry and multiple stage mass spectrometry experiments enabled the establishment of fragmentation schemes of both salts for the first time. Irradiation treatment indicated that phenylephrine bitartrate is more prone to degradation than the hydrochloride because of an additional decomposition sensitivity of the tartaric acid counter ion. An interaction between phenylephrine and its counter ion degradation products via a nucleophilic addition mechanism is suggested to be the explanation for the detected ion signals after irradiation treatment of phenylephrine bitartrate. PMID:20122809

  14. A gas ionisation Direct-STIM detector for MeV ion microscopy

    NASA Astrophysics Data System (ADS)

    Norarat, Rattanaporn; Guibert, Edouard; Jeanneret, Patrick; Dellea, Mario; Jenni, Josef; Roux, Adrien; Stoppini, Luc; Whitlow, Harry J.

    2015-04-01

    Direct-Scanning Transmission Ion Microscopy (Direct-STIM) is a powerful technique that yields structural information in sub-cellular whole cell imaging. Usually, a Si p-i-n diode is used in Direct-STIM measurements as a detector. In order to overcome the detrimental effects of radiation damage which appears as a broadening in the energy resolution, we have developed a gas ionisation detector for use with a focused ion beam. The design is based on the ETH Frisch grid-less off-axis Geiger-Müller geometry. It is developed for use in a MeV ion microscope with a standard Oxford Microbeams triplet lens and scanning system. The design has a large available solid angle for other detectors (e.g. proton induced fluorescence). Here we report the performance for imaging ReNcells VM with μm resolution where energy resolutions of <24 keV fwhm could be achieved for 1 MeV protons using isobutane gas.

  15. 100 years of Cosmic Rays - from the ionisation of air to beyond the LHC

    NASA Astrophysics Data System (ADS)

    Watson, Alan

    2012-03-01

    The study of cosmic rays has impacted on many disciplines, including astrophysics, particle physics, carbon dating and radio astronomy: it has thus had scientific and societal impact. They were discovered in 1912 as a result of the efforts by some of the most distinguished scientists of that era, puzzled by their inability to explain the discharge of ionisation chambers. I will describe some of the early work that led, inter alia, to the discovery of the positron, the muon and the first strange particles and thus to the birth of particle physics. In 1938 it was found that showers of particles that arrive at the earth simultaneously are produced by primary cosmic rays of ˜10^15 eV, about 10^5 times more energetic than any particles that had been contemplated before. I will discuss how study of these showers has led to the discovery of cosmic rays of energies as great as 3 x 10^20 eV, challenging our understanding of where and how they are created. Data from the Pierre Auger Observatory, the largest cosmic-ray detector ever built, is now being used for astrophysical studies and to give glimpses of some hadronic physics at centre-of-mass energies more than 4 times greater than are accessible at the LHC.

  16. Calibration, performance and type testing of personal dosemeters used in ionising-radiation applications in Greece.

    PubMed

    Boziari, A; Hourdakis, C J

    2007-01-01

    Active Personal Dosemeters (APDs) are widely used in real-time personal dosimetry. Their performance, operational characteristics and limitations, as well as their calibration should be routinely checked to assure satisfactory operation and safe use. This study summarises the results of such type tests and calibrations performed in almost 4750 dosemeters at Ionising Radiation Calibration Laboratory (HIRCL) of Greek Atomic Energy Commission (GAEC). About 13.8% of the pencil type and 4.3% of the electronic dosemeters were found to be out of limits of acceptable performance. For the pencil type dosemeters, the mean calibration factor (CF+/-SD) for high- and low-dose categories was found to be 1.014+/-0.102 (range 0.793-1.458) and 0.995+/-0.059 (range 0.794-1.311), respectively. Of these >85% of them had reproducibility better than 90%, while <1% showed remarkable non-linearity and approximately 10% of them failed to retain the dose reading within the limits after 24 h. For the electronic dosemeters, the mean CF was 1.034+/-0.046 (range 0.967-1.238). The majority of them showed good reproducibility and linearity results while, after irradiation, the dose readings were not shifted through time. The energy response varies with the dosemeter type, reaching in one dosemeter type down to 50%. Both electronic and pencil did not showed electronic equilibrium problems. PMID:17185312

  17. Artificially-aged cachaça samples characterised by direct infusion electrospray ionisation mass spectrometry.

    PubMed

    de Souza, Patterson P; Resende, Ana M M; Augusti, Daniella V; Badotti, Fernanda; Gomes, Fátima de Cássia O; Catharino, Rodrigo R; Eberlin, Marcos N; Augusti, Rodinei

    2014-01-15

    Direct infusion electrospray ionisation mass spectrometry in the negative ion mode [ESI(-)-MS] was employed to evaluate the authenticity of aged cachaças, a traditional and valuable Brazilian alcoholic beverage prepared from the distillation of brewed sugarcane juice and aged in barrels made of common woods. Counterfeit samples were prepared by adding dyes, sawdust or essences to a freshly-distiled, much less valuable sample (white cachaça) to simulate the 1-2years long natural ageing in wooden barrels. A simple visual inspection revealed remarkable differences between the ESI(-)-MS of the authentic samples (aged in oak or amburana casks) and the artificially-aged counterfeit samples. A set of diagnostic ions were detectable in the ESI(-)-MS of the authentic samples aged in oak (m/z 197, 241, 301 and 307) and amburana (m/z 271 and 377/379). This fast and direct methodology seems useful as a routine procedure to monitor this highly profitable and common counterfeit practice. PMID:24054215

  18. An isotopic analysis of ionising radiation as a source of sulphuric acid

    NASA Astrophysics Data System (ADS)

    Enghoff, M. B.; Bork, N.; Hattori, S.; Meusinger, C.; Nakagawa, M.; Pedersen, J. O. P.; Danielache, S.; Ueno, Y.; Johnson, M. S.; Yoshida, N.; Svensmark, H.

    2012-06-01

    Sulphuric acid is an important factor in aerosol nucleation and growth. It has been shown that ions enhance the formation of sulphuric acid aerosols, but the exact mechanism has remained undetermined. Furthermore some studies have found a deficiency in the sulphuric acid budget, suggesting a missing source. In this study the production of sulphuric acid from SO2 through a number of different pathways is investigated. The production methods are standard gas phase oxidation by OH radicals produced by ozone photolysis with UV light, liquid phase oxidation by ozone, and gas phase oxidation initiated by gamma rays. The distributions of stable sulphur isotopes in the products and substrate were measured using isotope ratio mass spectrometry. All methods produced sulphate enriched in 34S and we find an enrichment factor (δ34S) of 8.7 ± 0.4‰ (1 standard deviation) for the UV-initiated OH reaction. Only UV light (Hg emission at 253.65 nm) produced a clear non-mass-dependent excess of 33S. The pattern of isotopic enrichment produced by gamma rays is similar, but not equal, to that produced by aqueous oxidation of SO2 by ozone. This, combined with the relative yields of the experiments, suggests a mechanism in which ionising radiation may lead to hydrated ion clusters that serve as nanoreactors for S(IV) to S(VI) conversion.

  19. An isotope view on ionising radiation as a source of sulphuric acid

    NASA Astrophysics Data System (ADS)

    Enghoff, M. B.; Bork, N.; Hattori, S.; Meusinger, C.; Nakagawa, M.; Pedersen, J. O. P.; Danielache, S.; Ueno, Y.; Johnson, M. S.; Yoshida, N.; Svensmark, H.

    2012-02-01

    Sulphuric acid is an important factor in aerosol nucleation and growth. It has been shown that ions enhance the formation of sulphuric acid aerosols, but the exact mechanism has remained undetermined. Furthermore some studies have found a deficiency in the sulphuric acid budget, suggesting a missing source. In this study the production of sulphuric acid from SO2 through a number of different pathways is investigated. The production methods are standard gas phase oxidation by OH radicals produced by ozone photolysis with UV light, liquid phase oxidation by ozone, and gas phase oxidation initiated by gamma rays. The distributions of stable sulphur isotopes in the products and substrate were measured using isotope ratio mass spectrometry. All methods produced sulphate enriched in 34S and we find a δ34S value of 8.7 ± 0.4‰ (1 standard deviation) for the UV-initiated OH reaction. Only UV light (Hg emission at 253.65 nm) produced a clear non-mass-dependent excess of 33S. The pattern of isotopic enrichment produced by gamma rays is similar, but not equal, to that produced by aqueous oxidation of SO2 by ozone. This, combined with the relative yields of the experiments, suggests a mechanism in which ionising radiation may lead to hydrated ion clusters that serve as nanoreactors for S(IV) to S(VI) conversion.

  20. An isotopic view of ionising radiation as a source of sulphuric acid

    NASA Astrophysics Data System (ADS)

    Enghoff, M. B.; Bork, N.; Hattori, S.; Meusinger, C.; Nakagawa, M.; Pedersen, J. O. P.; Danielache, S. O.; Ueno, Y.; Johnson, M. S.; Yoshida, N.; Svensmark, H.

    2012-04-01

    Sulphuric acid is an important factor in aerosol nucleation and growth. It has been shown that ions enhance the formation of sulphuric acid aerosols, but the exact mechanism remains undetermined. Furthermore some studies have found a deficiency in the sulphuric acid budget, suggesting a missing source. In this study the production of sulphuric acid from SO2 through a number of different pathways is investigated. The production methods are standard gas phase oxidation by OH radicals produced by ozone photolysis with UV light, liquid phase oxidation by ozone, and gas phase oxidation initiated by gamma rays. The distributions of stable sulphur isotopes in the products and substrate were measured using isotope ratio mass spectrometry. All methods produced sulphate enriched in 34S and we find a d34S value of 8.7 ± 0.4 ‰ (1 standard deviation) for the UV-initiated OH reaction. Only UV light (Hg emission at 253.65 nm) produced a clear non-mass-dependent excess of 33S. The pattern of isotopic enrichment produced by gamma rays is similar, but not equal, to that produced by aqueous oxidation of SO2 by ozone. This, combined with the relative yields of the experiments, suggests a mechanism in which ionising radiation may lead to hydrated ion clusters that serve as nanoreactors for S(IV) to S(VI) conversion.

  1. Application of positive mode atmospheric chemical ionisation to distinguish epimeric oleanolic and ursolic acids.

    PubMed

    Townley, Chloe; Brettell, Rhea C; Bowen, Richard D; Gallagher, Richard T; Martin, William H C

    2015-01-01

    A new and more reliable method is reported for distinguishing the equatorial and axial epimers of oleanolic and ursolic acids and related triterpenoids based primarily on the relative abundance of the [M+H](+) and [M+-H(2)O](+) signals in their positive mode atmospheric pressure chemical ionisation mass spectra. The rate of elimination of water, which is the principal primary fragmentation of protonated oleanolic and ursolic acids, depends systematically on the stereochemistry of the hydroxyl group in the 3 position. For the b-epimer, in which the 3-hydroxyl substituent is in an equatorial position,[M+-H(2)O](+) is the base peak. In contrast, for the α-epimer, where the 3-hydroxyl group is axial, [M + H](+) is the base peak. This trend, which is general for a range of derivatives of oleanolic and ursolic acids, including the corresponding methyl esters, allows epimeric triterpenoids in these series to be securely differentiated. Confirmatory information is available from the collision-induced dissociation of the [M+-H(2)O](+) primary fragment ions, which follow different pathways for the species derived from axial and equatorial epimers of oleanolic and ursolic acids. These two pieces of independent spectral information permit the stereochemistry of epimeric oleanolic and ursolic acids (and selected derivatives) to be assigned with confidence without relying either on chromatographic retention times or referring to the spectra or other properties of authentic samples of these triterpenoids. PMID:26307724

  2. Effect of penetrating ionising radiation on the mechanical properties of pericardium

    NASA Astrophysics Data System (ADS)

    Daar, Eman; Woods, E.; Keddie, J. L.; Nisbet, A.; Bradley, D. A.

    2010-07-01

    The pericardium is an anistropic composite material made up of collagen and elastin fibres embedded in an amorphous matrix mainly composed of proteoglycan and hyaluronan. The collagen fibres are arranged in layers, with different directions of alignment in each layer, giving rise to interesting mechanical properties of pericardium, including the ability to undergo large deformation during performance of regular physiological functions. The present study aims to investigate the effect of penetrating photon ionising radiation on bovine pericardium tissue, being part of a study of the effect of cardiac doses received in breast radiotherapy and the possibility that this can give rise to cardiovascular complications. Irradiation doses in the range 5-80 Gy were used. To characterise the various mechanical properties [elastic modulus, stress relaxation, ultimate tensile strength (UTS) and fracture] a uniaxial tensile test method was applied. The preliminary results reflect the wide inter-sample variations that are expected in dealing with tissues, with only a weak indication of increase in the UTS of the pericardium tissue with increase in radiation dose. Such an effect has also been observed by others, with reduction in UTS at doses of 80 Gy.

  3. Resveratrol and its methoxy-derivatives as modulators of DNA damage induced by ionising radiation.

    PubMed

    Traversi, Gianandrea; Fiore, Mario; Leone, Stefano; Basso, Emiliano; Di Muzio, Elena; Polticelli, Fabio; Degrassi, Francesca; Cozzi, Renata

    2016-07-01

    Various naturally occurring stilbene-like compounds that are related to resveratrol (RSV) possess some of the beneficial effects of the parent molecule and provide even further benefits. Therefore, a series of methoxylated analogues of RSV were prepared with the aim of increasing antitumour and proapoptotic activity. In a previous article, we studied two methoxy-derivatives, pterostilbene (PTERO) and trimethoxystilbene (TRIMETHOXY), in which the first was formed by the substitution of two hydroxyl groups with two methoxy groups (trans-3,5-dimethoxy-4'-hydroxystilbene) and the second was formed by the replacement of all three OH groups with methoxy groups (trans-3,5,4'-trimethoxystilbene). Both methoxy-derivatives showed stronger antioxidant activity when compared with RSV. In the present article, we focused on the analysis of the ability of RSV and its two methoxylated derivatives to protect proliferating non-tumoural cells from the damage induced by ionising radiation (IR). First we showed that the methoxy derivatives, contrary to their parental compound, are unable to affect topoisomerase enzyme and consequently are not clastogenic per se Second we showed that both PTERO and TRIMETHOXY more efficiently reduce the chromosome damage induced by IR. Furthermore, TRIMETHOXY, but not PTERO, causes a delay in cell proliferation, particularly in mitosis progression increasing the number of cells in metaphase at the expense of prophases and ana/telophases. PMID:26819346

  4. Beer fingerprinting by Matrix-Assisted Laser Desorption-Ionisation-Time of Flight Mass Spectrometry.

    PubMed

    Šedo, Ondrej; Márová, Ivana; Zdráhal, Zbyněk

    2012-11-15

    A method allowing parallel fingerprinting of proteins and maltooligosaccharides directly from untreated beer samples is presented. These two classes of compounds were detected by Matrix-Assisted Laser Desorption-Ionisation-Time of Flight-Mass Spectrometry (MALDI-TOF-MS) analysis of beer mixed with 2,5-dihydroxybenzoic acid solution. The maltooligosaccharide profiles acquired from the MALDI sample spot center were not found characteristic for beers of different source and technology. On the other hand, according to profiles containing protein signals acquired from crystals formed on the border of the MALDI sample spot, we were able to distinguish beer samples of the same brand produced by different breweries. The discriminatory abilities of the method were further examined on a set of 17 lager beers, where the fingerprints containing protein signals enabled resolution of majority of examined brands. We propose MALDI-TOF-MS profiling as a rapid tool for beer brewing technology process monitoring, quality control, and determination of beer authenticity. PMID:22868116

  5. Xpg limits the expansion of haematopoietic stem and progenitor cells after ionising radiation.

    PubMed

    Avila, Alush I; Illing, Anett; Becker, Friedrich; Maerz, Lars D; Morita, Yohei; Philipp, Melanie; Burkhalter, Martin D

    2016-07-27

    Reduced capacity of genome maintenance represents a problem for any organism, potentially causing premature death, carcinogenesis, or accelerated ageing. Strikingly though, loss of certain genome stability factors can be beneficial, especially for the maintenance of tissue stem cells of the intestine and the haematopoietic system. We therefore screened for genome stability factors negatively impacting maintenance of haematopoietic stem cells (HSC) in the context of ionising radiation (IR). We found that in vivo knock down of Xeroderma pigmentosum, complementation group G (Xpg) causes elevation of HSC numbers after IR treatment, while numbers of haematopoietic progenitors are elevated to a lesser extent. IR rapidly induces Xpg both on mRNA and on protein level. Prevention of this induction does not influence activation of the checkpoint cascade, yet attenuates late checkpoint steps such as induction of p21 and Noxa. This causes a leaky cell cycle arrest and lower levels of apoptosis, both contributing to increased colony formation and transformation rates. Xpg thus helps to adequately induce DNA damage responses after IR, thereby keeping the expansion of damaged cells under control. This represents a new function of Xpg in the response to IR, in addition to its well-characterized role in nucleotide excision repair. PMID:27137888

  6. Radiation safety in the nuclear medicine department: impact of the UK Ionising Radiations Regulations.

    PubMed

    Harding, L K

    1987-09-01

    The practice of nuclear medicine requires integration of radiation safety with patient care and radiopharmaceutical standards. Nationally there was useful discussion in the UK before the Ionising Radiations Regulations and Approved Code of Practice were published, although such consultation had been lacking when the Medicines Act was implemented. Most of the new considerations relating to nuclear medicine stem from Schedule 6 of the Regulations. Generally, the presence of a single patient does not require a controlled area. However, when several patients are present, or radiopharmaceuticals are being prepared prior to injection, a controlled area is required. Classification of workers is not likely to be required in a typical nuclear medicine department in the UK, although most parts of the nuclear medicine department will need to be controlled areas. These include the radiopharmacy, radionuclide dispensary, injection room, and imaging rooms if patients are injected in them. The importance of finger dose measurements is emphasised. Patient wards, however, need not be controlled areas. A particular concern in nuclear medicine was that patients should not need to be admitted to hospital merely to comply with legislation. This is possibly the case and clarification will probably be available when the Notes for Guidance are published. Most procedures in nuclear medicine departments will remain unchanged. Further information is required, however, on patient waiting rooms, handling flood sources, pregnancy, and breast feeding. Within the hospital, detailed and multidisciplinary discussion will need to take place within the forum of the radiation safety committee. PMID:3664186

  7. Risk of cancer after low doses of ionising radiation: retrospective cohort study in 15 countries

    PubMed Central

    Cardis, E; Vrijheid, M; Blettner, M; Gilbert, E; Hakama, M; Hill, C; Howe, G; Kaldor, J; Muirhead, C R; Schubauer-Berigan, M; Yoshimura, T; Bermann, F; Cowper, G; Fix, J; Hacker, C; Heinmiller, B; Marshall, M; Thierry-Chef, I; Utterback, D; Ahn, Y-O; Amoros, E; Ashmore, P; Auvinen, A; Bae, J-M; Solano, J Bernar; Biau, A; Combalot, E; Deboodt, P; Sacristan, A Diez; Eklof, M; Engels, H; Engholm, G; Gulis, G; Habib, R; Holan, K; Hyvonen, H; Kerekes, A; Kurtinaitis, J; Malker, H; Martuzzi, M; Mastauskas, A; Monnet, A; Moser, M; Pearce, M S; Richardson, D B; Rodriguez-Artalejo, F; Rogel, A; Tardy, H; Telle-Lamberton, M; Turai, I; Usel, M; Veress, K

    2005-01-01

    Objectives To provide direct estimates of risk of cancer after protracted low doses of ionising radiation and to strengthen the scientific basis of radiation protection standards for environmental, occupational, and medical diagnostic exposures. Design Multinational retrospective cohort study of cancer mortality. Setting Cohorts of workers in the nuclear industry in 15 countries. Participants 407 391 workers individually monitored for external radiation with a total follow-up of 5.2 million person years. Main outcome measurements Estimates of excess relative risks per sievert (Sv) of radiation dose for mortality from cancers other than leukaemia and from leukaemia excluding chronic lymphocytic leukaemia, the main causes of death considered by radiation protection authorities. Results The excess relative risk for cancers other than leukaemia was 0.97 per Sv, 95% confidence interval 0.14 to 1.97. Analyses of causes of death related or unrelated to smoking indicate that, although confounding by smoking may be present, it is unlikely to explain all of this increased risk. The excess relative risk for leukaemia excluding chronic lymphocytic leukaemia was 1.93 per Sv (< 0 to 8.47). On the basis of these estimates, 1-2% of deaths from cancer among workers in this cohort may be attributable to radiation. Conclusions These estimates, from the largest study of nuclear workers ever conducted, are higher than, but statistically compatible with, the risk estimates used for current radiation protection standards. The results suggest that there is a small excess risk of cancer, even at the low doses and dose rates typically received by nuclear workers in this study. PMID:15987704

  8. The Vertical Structure of Warm Ionised Gas in the Milky Way

    NASA Astrophysics Data System (ADS)

    Gaensler, B. M.; Madsen, G. J.; Chatterjee, S.; Mao, S. A.

    2008-11-01

    We present a new joint analysis of pulsar dispersion measures and diffuse Hα emission in the Milky Way, which we use to derive the density, pressure and filling factor of the thick disk component of the warm ionised medium (WIM) as a function of height above the Galactic disk. By excluding sightlines at low Galactic latitude that are contaminated by Hii regions and spiral arms, we find that the exponential scale-height of free electrons in the diffuse WIM is 1830-250+120 pc, a factor of two larger than has been derived in previous studies. The corresponding inconsistent scale heights for dispersion measure and emission measure imply that the vertical profiles of mass and pressure in the WIM are decoupled, and that the filling factor of WIM clouds is a geometric response to the competing environmental influences of thermal and non-thermal processes. Extrapolating the properties of the thick-disk WIM to mid-plane, we infer a volume-averaged electron density 0.014 +/- 0.001 cm-3, produced by clouds of typical electron density 0.34 +/- 0.06 cm-3 with a volume filling factor 0.04 +/- 0.01. As one moves off the plane, the filling factor increases to a maximum of ~30% at a height of ~1-1.5 kpc, before then declining to accommodate the increasing presence of hot, coronal gas. Since models for the WIM with a ~1 kpc scale-height have been widely used to estimate distances to radio pulsars, our revised parameters suggest that the distances to many high-latitude pulsars have been substantially underestimated.

  9. Age at exposure to ionising radiation and cancer mortality among Hanford workers: follow up through 1994

    PubMed Central

    Wing, S; Richardson, D

    2005-01-01

    Background: Studies of workers at the plutonium production factory in Hanford, WA have led to conflicting conclusions about the role of age at exposure as a modifier of associations between ionising radiation and cancer. Aims: To evaluate the influence of age at exposure on radiation risk estimates in an updated follow up of Hanford workers. Methods: A cohort of 26 389 workers hired between 1944 and 1978 was followed through 1994 to ascertain vital status and causes of death. External radiation dose estimates were derived from personal dosimeters. Poisson regression was used to estimate associations between mortality and cumulative external radiation dose at all ages, and in specific age ranges. Results: A total of 8153 deaths were identified, 2265 of which included cancer as an underlying or contributory cause. Estimates of the excess relative risk per Sievert (ERR/Sv) for cumulative radiation doses at all ages combined were negative for all cause and leukaemia and positive for all cancer and lung cancer. Cumulative doses accrued at ages below 35, 35–44, and 45–54 showed little association with mortality. For cumulative dose accrued at ages 55 and above (10 year lag), the estimated ERR/Sv for all cancers was 3.24 (90% CI: 0.80 to 6.17), primarily due to an association with lung cancer (ERR/Sv: 9.05, 90% CI: 2.96 to 17.92). Conclusions: Associations between radiation and cancer mortality in this cohort are primarily a function of doses at older ages and deaths from lung cancer. The association of older age radiation exposures and cancer mortality is similar to observations from several other occupational studies. PMID:15961623

  10. Ionising Radiation Exposure to Orthopaedic Trainees: The Effect of Sub-Specialty Training

    PubMed Central

    Oddy, MJ; Aldam, CH

    2006-01-01

    INTRODUCTION We monitored image intensifier use by orthopaedic trainees to assess their exposure to ionising radiation and to investigate the influence of sub-specialty training. MATERIALS AND METHODS Five different orthopaedic registrars recorded their monthly image intensifier screening times and exposure doses for all cases (trauma and elective), for a combined total of 12 non-consecutive months. Radiation exposure was monitored using shoulder and waist film badges worn both by surgeons and radiographers screening their cases. RESULTS Registrars in spinal sub-specialties were exposed to significantly higher doses per case and cumulative doses per month than non-spinal trainees (P < 0.05), but significantly lower screening times per case (P < 0.05). There were no significant differences in cumulative screening times per month (P > 0.05). Regression analysis for all surgeons showed a significant relationship between shoulder film badge reading and cumulative dose exposed per month (P < 0.05), but not for cumulative screening time. Shoulder film badge recordings were significantly higher for spinal compared with non-spinal registrars (P < 0.05), although all badges were below the level for radiation reporting. Only one radiographer badge recorded a dose above threshold. CONCLUSIONS Whilst the long-term effects of sub-reporting doses of radiation are not fully understood, we consider that this study demonstrates that trainees should not be complacent in accepting inadequate radiation protection. The higher doses encountered with spinal imaging means that sub-specialty trainees should be alerted to the risk of their increased exposure. The principle of minimising radiation exposure must be maintained by all trainees at all times. PMID:16720002

  11. Low-dose ionising radiation and cardiovascular diseases--Strategies for molecular epidemiological studies in Europe.

    PubMed

    Kreuzer, Michaela; Auvinen, Anssi; Cardis, Elisabeth; Hall, Janet; Jourdain, Jean-Rene; Laurier, Dominique; Little, Mark P; Peters, Annette; Raj, Ken; Russell, Nicola S; Tapio, Soile; Zhang, Wei; Gomolka, Maria

    2015-01-01

    It is well established that high-dose ionising radiation causes cardiovascular diseases. In contrast, the evidence for a causal relationship between long-term risk of cardiovascular diseases after moderate doses (0.5-5 Gy) is suggestive and weak after low doses (<0.5 Gy). However, evidence is emerging that doses under 0.5 Gy may also increase long-term risk of cardiovascular disease. This would have major implications for radiation protection with respect to medical use of radiation for diagnostic purposes and occupational or environmental radiation exposure. Therefore, it is of great importance to gain information about the presence and possible magnitude of radiation-related cardiovascular disease risk at doses of less than 0.5 Gy. The biological mechanisms implicated in any such effects are unclear and results from epidemiological studies are inconsistent. Molecular epidemiological studies can improve the understanding of the pathogenesis and the risk estimation of radiation-induced circulatory disease at low doses. Within the European DoReMi (Low Dose Research towards Multidisciplinary Integration) project, strategies to conduct molecular epidemiological studies in this field have been developed and evaluated. Key potentially useful European cohorts are the Mayak workers, other nuclear workers, uranium miners, Chernobyl liquidators, the Techa river residents and several diagnostic or low-dose radiotherapy patient cohorts. Criteria for informative studies are given and biomarkers to be investigated suggested. A close collaboration between epidemiology, biology and dosimetry is recommended, not only among experts in the radiation field, but also those in cardiovascular diseases. PMID:26041268

  12. Ionised concentrations in calcium and magnesium buffers: Standards and precise measurement are mandatory.

    PubMed

    McGuigan, John A S; Kay, James W; Elder, Hugh Y

    2016-09-01

    In Ca(2+) and Mg(2+) buffer solutions the ionised concentrations ([X(2+)]) are either calculated or measured. Calculated values vary by up to a factor of seven due to the following four problems: 1) There is no agreement amongst the tabulated constants in the literature. These constants have usually to be corrected for ionic strength and temperature. 2) The ionic strength correction entails the calculation of the single ion activity coefficient, which involves non-thermodynamic assumptions; the data for temperature correction is not always available. 3) Measured pH is in terms of activity i.e. pHa. pHa measurements are complicated by the change in the liquid junction potentials at the reference electrode making an accurate conversion from H(+) activity to H(+) concentration uncertain. 4) Ligands such as EGTA bind water and are not 100% pure. Ligand purity has to be measured, even when the [X(2+)] are calculated. The calculated [X(2+)] in buffers are so inconsistent that calculation is not an option. Until standards are available, the [X(2+)] in the buffers must be measured. The Ligand Optimisation Method is an accurate and independently verified method of doing this (McGuigan & Stumpff, Anal. Biochem. 436, 29, 2013). Lack of standards means it is not possible to compare the published [Ca(2+)] in the nmolar range, and the apparent constant (K(/)) values for Ca(2+) and Mg(2+) binding to intracellular ligands amongst different laboratories. Standardisation of Ca(2+)/Mg(2+) buffers is now essential. The parameters to achieve this are proposed. PMID:26975789

  13. Étude théorique et expérimentale du transfert du dioctyl phtalate à partir d'un disque de PVC plastifié plongé dans une huile comestible

    NASA Astrophysics Data System (ADS)

    Djilani, S.-E.; Toubal, A. A.; Messadi, D.

    1998-10-01

    When polymer and liquid are contacted with each other, as in packaging, some mass exchanges may occur, which constitute a major drawback when the liquid is a foodstuff or blood. However, these mass transfers in the polymers can appear as very interesting from the industrial point of view, if one is able to use and control them. It is then necessary to have a good knowledge of these transfer processes which are controlled by diffusion. Dioctyl phthalate (DOP) migration into an edible oil was studied under worst conditions: high plasticization level (50% by weight) and temperature(30 circC). The quantitative analysis of DOP in a such complex liquid medium and in the PVC itself was made easy by the use of the radioactive tracer technique. A simplified mathematical model, obtained by neglecting the oil transport in the PVC, was evaluated. This model based on the research of a finite differences explicit solution allows to reproduce for the DOP, the concentration profiles in the polymer and the kinetics of transfer in the oil, with a P-value ≥ 0.001. La mise en contact polymère-liquide se traduit généralement par des échanges de matière entre les 2 milieux considérés, ce qui constitue un inconvénient majeur lorsque le liquide est un aliment ou le sang. Cependant, ces transferts de matière dans les polymères peuvent apparaître comme très intéressants sur le plan industriel, si l'on est capable de les utiliser et de les contrôler. Il est donc nécessaire d'avoir une bonne connaissance de ces processus de transfert qui sont contrôlés par diffusion. Nous avons étudié la migration du dioctyl phtalate (DOP) dans une huile comestible en nous plaçant dans les conditions les plus défavorables: taux de plastification (50% en poids) et température (30°C) élevés. L'analyse quantitative du DOP dans un milieu liquide aussi complexe et dans le PVC lui- même a été facilitée par l'utilisation de la technique des traceurs radioactifs. Un modèle math

  14. Laser ablation and ionisation by laser plasma radiation in the atmospheric-pressure mass spectrometry of organic compounds

    SciTech Connect

    Pento, A V; Nikiforov, S M; Simanovsky, Ya O; Grechnikov, A A; Alimpiev, S S

    2013-01-31

    A new method was developed for the mass spectrometric analysis of organic and bioorganic compounds, which involves laser ablation with the ionisation of its products by laser-plasma radiation and enables analysing gaseous, liquid, and solid substances at atmospheric pressure without sample preparation. The capabilities of this method were demonstrated by the examples of fast pharmaceutical composition screening, real-time atmosphere composition analysis, and construction of the mass spectrometric images of organic compound distributions in biological materials. (interaction of laser radiation with matter)

  15. Capillary electrophoresis with electrospray ionisation-mass spectrometry for the characterisation of degradation products in aged papers.

    PubMed

    Dupont, Anne-Laurence; Seemann, Agathe; Lavédrine, Bertrand

    2012-01-30

    A methodology for capillary electrophoresis/electrospray ionisation mass spectrometry (CE/ESI-MS) was developed for the simultaneous analysis of degradation products from paper among two families of compounds: low molar mass aliphatic organic acids, and aromatic (phenolic and furanic) compounds. The work comprises the optimisation of the CE separation and the ESI-MS parameters for improved sensitivity with model compounds using two successive designs of experiments. The method was applied to the analysis of lignocellulosic paper at different stages of accelerated hygrothermal ageing. The compounds of interest were identified. Most of them could be quantified and several additional analytes were separated. PMID:22284496

  16. Ionisation and fragmentation of polycyclic aromatic hydrocarbons by femtosecond laser pulses at wavelengths resonant with cation transitions

    NASA Astrophysics Data System (ADS)

    Robson, L.; Ledingham, K. W. D.; Tasker, A. D.; McKenna, P.; McCanny, T.; Kosmidis, C.; Jaroszynski, D. A.; Jones, D. R.; Issac, R. C.; Jamieson, S.

    2002-07-01

    When femtosecond laser pulses irradiate hydrocarbon molecules, then many fragmentation channels evident in nanosecond irradiation are bypassed, providing a strong analytically useful parent ion. However a number of molecules show only a very small or indeed no parent ions and recent papers suggest that those that do not produce parent peaks have cation transitions in resonance with the femtosecond laser wavelength. This Letter shows that this resonance effect is not universal and some aromatic molecules not only show strong parent peaks but also doubly and triply ionised entities when their cation absorption spectrum is strongly resonant at either the 800 or 400 nm or indeed both.

  17. Chemotaxonomy of bacteria by comprehensive GC and GC-MS in electron impact and chemical ionisation mode.

    PubMed

    David, Frank; Tienpont, Bart; Sandra, Pat

    2008-10-01

    The analysis of the cellular lipidic fraction of bacteria is described. After hydrolysis and methylation, the fatty acid methyl esters (FAMEs) are determined by 1-D GC using the Sherlock MIDI bacteria identification system, by comprehensive GC (GC x GC) and by GC-MS in electron impact (EI) and positive chemical ionisation (PCI) mode. With GC x GC, the enhanced selectivity and group type separation provides a more complete elucidation of the fatty acids in microorganisms. GC-EI-MS and GC-PCI-MS were helpful for confirmation. The bacteria selected in this study are Brevundimonas diminuta, Chryseobacterium gleum and Stenotrophomonas maltophilia. PMID:18792008

  18. New laboratory atomic data for neutral, singly and doubly ionised iron group elements for astrophysics applications

    NASA Astrophysics Data System (ADS)

    Pickering, Juliet C.; Nave, Gillian; Liggins, Florence; Clear, Christian; Ruffoni, Matthew; Sansonetti, Craig

    2015-08-01

    We present new laboratory spectroscopic measurements to produce atomic data for astrophysically important species: neutral, singly and doubly ionised iron group elements.We use high resolution Fourier Transform Spectrometry (FTS) (resolving power up to 2x106 at 200nm) to measure atomic spectra, giving accurate line wavelengths (to a few parts in 108), atomic energy levels, hyperfine structure splitting and log gfs (accurate to a few %) (Ruffoni et al this meeting). These data are vital for astrophysical spectral analyses for: line identification, spectrum synthesis, elemental abundance determinations [eg 1], and disentangling of blends etc. It is not possible to theoretically calculate these atomic data to the accuracy needed for modern astrophysics applications.At Imperial College we have a unique visible-VUV FT spectrometer with short wavelength cut-off of 135nm. We supplement FTS data at shorter wavelengths with spectra recorded on the NIST 10.7m grating spectrograph (with phosphor image or photographic plates) and at longer wavelengths in the IR we use the NIST IR FT spectrometer.An elemental spectrum may contain thousands of spectral lines from the IR to VUV. We use these wavelengths to correct known atomic energy levels, and search for new atomic levels. The result is a classified linelist and accurate atomic energy levels.We present progress on iron group element atomic energy levels and wavelengths for V I and V II [2,3], Co III [4], Cr I, Mn I and Mn II, and Ni II.This work is supported by STFC(UK), The Leverhulme Trust, The Royal Society and NASA.References[1] Bergemann M, Pickering JC & Gehren T,“NLTE analysis of Co I/Co II lines in spectra of cool stars with new laboratory hyperfine splitting constants",MNRAS 401(2) 1334 (2010)[2] Thorne AP, Pickering JC & Semeniuk J,“The spectrum and term analysis of V II”, ApJS 207,13 (2013)[3] Thorne AP, Pickering JC & Semeniuk J,“The spectrum and term analysis of V I",ApJS 192,11 (2011)[4] Smillie DG

  19. The multiple stressor effect in zebrafish embryos from simultaneous exposure to ionising radiation and cadmium.

    PubMed

    Ng, C Y P; Choi, V W Y; Lam, A C L; Cheng, S H; Yu, K N

    2013-03-01

    Living organisms are exposed to a mixture of environmental stressors, and the resultant effects are referred to as multiple stressor effects. In the present work, we studied the multiple stressor effect in embryos of the zebrafish (Danio rerio) from simultaneous exposure to ionising radiation (alpha particles) and cadmium through quantification of apoptotic signals at 24 h postfertilisation (hpf) revealed by vital dye acridine orange staining. For each set of experiments, 32-40 dechorionated embryos were deployed, which were divided into four groups each having 8-10 embryos. The four groups of embryos were referred to as (1) the control group (C), which received no further treatments after dechorionation; (2) the Cd-dosed and irradiated group (CdIr), which was exposed to 100 μM Cd from 5 to 24 hpf, and also received about 4.4 mGy from alpha particles at 5 hpf; (3) the irradiated group (Ir), which received about 4.4 mGy from alpha particles at 5 hpf; and (4) the Cd-dosed group (Cd), which was exposed to 100 μM Cd from 5 to 24 hpf. In general, the CdIr, Ir and Cd groups had more apoptotic signals than the C group. Within the 12 sets of experimental results, two showed significant synergistic effects, one showed a weakly synergistic effect and nine showed additive effects. The multiple stressor effect of 100 μM Cd with ~4.4 mGy alpha-particle radiation resulted in an additive or synergistic effect, but no antagonistic effect. The failure to identify significant synergistic effects for some sets of data, and thus their subsequent classification as additive effects, might be a result of the relatively small magnitude of the synergistic effects. The results showed that the radiation risk could be perturbed by another environmental stressor such as a heavy metal, and as such a realistic human radiation risk assessment should in general take into account the multiple stressor effects. PMID:23296360

  20. Determination of chlorinated paraffins in sediments from the Firth of Clyde by gas chromatography with electron capture negative ionisation mass spectrometry and carbon skeleton analysis by gas chromatography with flame ionisation detection.

    PubMed

    Hussy, Ines; Webster, Lynda; Russell, Marie; Moffat, Colin

    2012-07-01

    Short chain chlorinated paraffins (SCCPs) are a group of persistent organic pollutants (POPs) of increasing concern, but are to date not widely investigated in the environment, largely due to the challenges involved in their quantification. Here, SCCPs were quantified in marine sediments from the Firth of Clyde, Scotland, by gas chromatography with electron capture negative ionisation mass spectrometry (GC-ECNIMS) and through carbon skeleton analysis by gas chromatography with flame ionisation detection (GC-FID), and the analytical challenges encountered are discussed. Concentrations in the sediments ranged from 0.4 to 69 μg kg(-1) when determined by GC-ECNIMS, and from 5.6 to 379 μg kg(-1) when determined by GC-FID. For 8 out of 11 samples, analysis by GC-FID gave higher results than analysis by GC-ECNIMS. Unexpected aspects of the analysis, such as the presence of high concentrations of longer chain chlorinated paraffins in the samples, are also presented. PMID:22417782

  1. Letter: characterisation and identification of spermine and spermidine derivatives in Microdesmis keayana and Microdesmis puberula roots by electrospray ionisation tandem mass spectrometry and high-performance liquid chromatography/electrospray ionisation tandem mass spectrometry.

    PubMed

    Roumy, Vincent; Hennebelle, Thierry; Zamblé, Alexis; Zamblé Yao, Jacques; Sahpaz, Sevser; Bailleul, François

    2008-01-01

    Three new N(1),N(5),N(14)-tris(4- hydroxycinnamoyl)spermines were identified in hydromethanolic root extracts of Microdesmis keayana J. Léonard and Microdesmis puberula Hook f. The electrospray ionisation tandem mass spectrometry (ESI-MS/MS) technique with specific nuclear magnetic resonance analysis of hydrolysed products made it possible to identify N(1),N(5),N(14)-tris(p-coumaroyl)spermine, N(1)-feruloyl,N(5),N(14)-di(p-coumaroyl)spermine and N(1),N(5),N(14)-tris(feruloyl)spermine, named keayanines B, C and D, respectively. ESI-MS/MS analysis most effectively provided structural data although high-performance liquid chromatography/electrospray ionisation tandem mass spectrometry was also used to characterise four other compounds from Microdesmis puberula-keayanidines A, B, C and keayanine A-which had already been identified in M. keayana. This chemical data is the first to be published for M. puberula which is a commonly used plant in Central African traditional medicine. PMID:18493101

  2. Thermally annealed gold nanoparticles for surface-assisted laser desorption ionisation-mass spectrometry of low molecular weight analytes.

    PubMed

    Pilolli, Rosa; Ditaranto, Nicoletta; Di Franco, Cinzia; Palmisano, Francesco; Cioffi, Nicola

    2012-10-01

    Metal nanomaterials have an emerging role in surface-assisted laser desorption ionisation-mass spectrometry (SALDI-MS) providing a useful tool to overcome some limitations intrinsically related to the use of conventional organic matrices in matrix-assisted LDI-MS. In this contribution, the possibility to use a stainless-steel-supported gold nanoparticle (AuNP) film as a versatile platform for SALDI-MS was assessed. A sacrificial anode electrosynthetic route was chosen in order to obtain morphologically controlled core-shell AuNPs; the colloidal AuNPs were, thereafter, drop cast onto a stainless-steel sample plate and the resulting AuNP film was thermally annealed in order to improve its effectiveness as LDI-MS promoter. Spectroscopic characterization of the nanostructured film by X-ray photoelectron spectroscopy was crucial for understanding how annealing induced changes in the surface chemistry and influenced the performance of AuNPs as desorption/ionisation promoter. In particular, it was demonstrated that the post-deposition treatments were essential to enhance the AuNP core/analyte interaction, thus resulting in SALDI-MS spectra of significantly improved quality. The AuNP films were applied to the detection of three different classes of low molecular weight (LMW) analytes, i.e. amino acids, peptides and LMW polymers, in order to demonstrate the versatility of this nanostructured material. PMID:22825677

  3. Internet-based ICRP resource for healthcare providers on the risks and benefits of medical imaging that uses ionising radiation.

    PubMed

    Demeter, S; Applegate, K E; Perez, M

    2016-06-01

    The purpose of the International Commission on Radiological Protection (ICRP) Committee 3 Working Party was to update the 2001 web-based module 'Radiation and your patient: a guide for medical practitioners' from ICRP. The key elements of this task were: to clearly identify the target audience (such as healthcare providers with an emphasis on primary care); to review other reputable sources of information; and to succinctly publish the contribution made by ICRP to the various topics. A 'question-and-answer' format addressing practical topics was adopted. These topics included benefits and risks of imaging using ionising radiation in common medical situations, as well as pertaining to specific populations such as pregnant, breast-feeding, and paediatric patients. In general, the benefits of medical imaging and related procedures far outweigh the potential risks associated with ionising radiation exposure. However, it is still important to ensure that the examinations are clinically justified, that the procedure is optimised to deliver the lowest dose commensurate with the medical purpose, and that consideration is given to diagnostic reference levels for particular classes of examinations. PMID:27012846

  4. Vertical ionisation potentials of a number of crown ethers from charge transfer bands of their EDA complexes

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Sumanta; Sharma, Anubha; Nayak, Sandip K.; Mukherjee, Asok K.

    2002-11-01

    Vertical ionisation potentials ( IDv) of a number of crown ethers, viz. dibenzo-30-crown-10 (Crown 1), benzo-15-crown-5 (Crown 2), dibenzo-24-crown-8 (Crown 3), dicyclohexano-24-crown-8 (Crown 4) and 4'-nitrobenzo-15-crown-5 (Crown 5) are being reported for the first time from a study of EDA interaction of these crown ethers with a number of electron acceptors like C 60, C 70, o-chloranil, p-chloranil, 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) and pyromellitic diimide (PMD). The study has been carried out in CCl 4 medium by electronic absorption spectroscopy. Charge transfer (CT) absorption bands in the 360-900 nm range have been found in each case (excepting the 60 fullerene-Crown 4 system). The vertical ionisation potentials ( IDv) of all the crown ethers thus determined show a good correlation with those calculated by the semiempirical AM1 method. Of the six acceptors under study the vertical electron affinity of PMD was not found in the literature. This has also been determined from an analysis of the present hνCT data.

  5. Solvent Separating Secondary Metabolites Directly from Biosynthetic Tissue for Surface-Assisted Laser Desorption Ionisation Mass Spectrometry

    PubMed Central

    Rudd, David; Benkendorff, Kirsten; Voelcker, Nicolas H.

    2015-01-01

    Marine bioactive metabolites are often heterogeneously expressed in tissues both spatially and over time. Therefore, traditional solvent extraction methods benefit from an understanding of the in situ sites of biosynthesis and storage to deal with heterogeneity and maximize yield. Recently, surface-assisted mass spectrometry (MS) methods namely nanostructure-assisted laser desorption ionisation (NALDI) and desorption ionisation on porous silicon (DIOS) surfaces have been developed to enable the direct detection of low molecular weight metabolites. Since direct tissue NALDI-MS or DIOS-MS produce complex spectra due to the wide variety of other metabolites and fragments present in the low mass range, we report here the use of “on surface” solvent separation directly from mollusc tissue onto nanostructured surfaces for MS analysis, as a mechanism for simplifying data annotation and detecting possible artefacts from compound delocalization during the preparative steps. Water, ethanol, chloroform and hexane selectively extracted a range of choline esters, brominated indoles and lipids from Dicathais orbita hypobranchial tissue imprints. These compounds could be quantified on the nanostructured surfaces by comparison to standard curves generated from the pure compounds. Surface-assisted MS could have broad utility for detecting a broad range of secondary metabolites in complex marine tissue samples. PMID:25786067

  6. Airborne hydrogen cyanide measurements using a chemical ionisation mass spectrometer for the plume identification of biomass burning forest fires

    NASA Astrophysics Data System (ADS)

    Le Breton, M.; Bacak, A.; Muller, J. B. A.; O'Shea, S. J.; Xiao, P.; Ashfold, M. N. R.; Cooke, M. C.; Batt, R.; Shallcross, D. E.; Oram, D. E.; Forster, G.; Bauguitte, S. J.-B.; Percival, C. J.

    2013-09-01

    A chemical ionisation mass spectrometer (CIMS) was developed for measuring hydrogen cyanide (HCN) from biomass burning events in Canada using I- reagent ions on board the FAAM BAe-146 research aircraft during the BORTAS campaign in 2011. The ionisation scheme enabled highly sensitive measurements at 1 Hz frequency through biomass burning plumes in the troposphere. A strong correlation between the HCN, carbon monoxide (CO) and acetonitrile (CH3CN) was observed, indicating the potential of HCN as a biomass burning (BB) marker. A plume was defined as being 6 standard deviations above background for the flights. This method was compared with a number of alternative plume-defining techniques employing CO and CH3CN measurements. The 6-sigma technique produced the highest R2 values for correlations with CO. A normalised excess mixing ratio (NEMR) of 3.68 ± 0.149 pptv ppbv-1 was calculated, which is within the range quoted in previous research (Hornbrook et al., 2011). The global tropospheric model STOCHEM-CRI incorporated both the observed ratio and extreme ratios derived from other studies to generate global emission totals of HCN via biomass burning. Using the ratio derived from this work, the emission total for HCN from BB was 0.92 Tg (N) yr-1.

  7. Airborne hydrogen cyanide measurements using a chemical ionisation mass spectrometer for the plume identification of biomass burning forest fires

    NASA Astrophysics Data System (ADS)

    Le Breton, M.; Bacak, A.; Muller, J. B. A.; O'Shea, S. J.; Xiao, P.; Ashfold, M. N. R.; Cooke, M. C.; Batt, R.; Shallcross, D. E.; Oram, D. E.; Forster, G.; Bauguitte, S. J.-B.; Percival, C. J.

    2013-02-01

    A Chemical Ionisation Mass Spectrometer (CIMS) was developed for measuring hydrogen cyanide (HCN) from biomass burning events in Canada using I- reagent ions on board the FAAM BAe-146 research aircraft during the BORTAS campaign in 2011. The ionisation scheme enabled highly sensitive measurements at 1 Hz frequency through biomass burning plumes in the troposphere. A strong correlation between the HCN, carbon monoxide (CO) and acetonitrile (CH3CN) was observed, indicating the potential of HCN as a biomass burning (BB) marker. A plume was defined as being 6 standard deviations above background for the flights. This method was compared with a number of alternative plume defining techniques employing CO and CH3CN measurements. The 6 sigma technique produced the highest R2 values for correlations with CO. A Normalised Excess Mixing Ratio (NEMR) of 3.76 ± 0.022 pptv ppbv-1 was calculated which is within the range quoted in previous research (Hornbrook et al., 2011). The global tropospheric model STOCHEM-CRI incorporated both the observed ratio and extreme ratios derived from other studies to generate global emission totals of HCN via biomass burning. Using the ratio derived from this work the emission total for HCN from BB was 0.92 Tg (N) yr-1.

  8. Leaf Anatomy and Photochemical Behaviour of Solanum lycopersicum L. Plants from Seeds Irradiated with Low-LET Ionising Radiation

    PubMed Central

    De Micco, V.; Paradiso, R.; Aronne, G.; De Pascale, S.; Quarto, M.; Arena, C.

    2014-01-01

    Plants can be exposed to ionising radiation not only in Space but also on Earth, due to specific technological applications or after nuclear disasters. The response of plants to ionising radiation depends on radiation quality/quantity and/or plant characteristics. In this paper, we analyse some growth traits, leaf anatomy, and ecophysiological features of plants of Solanum lycopersicum L. “Microtom” grown from seeds irradiated with increasing doses of X-rays (0.3, 10, 20, 50, and 100 Gy). Both juvenile and compound leaves from plants developed from irradiated and control seeds were analysed through light and epifluorescence microscopy. Digital image analysis allowed quantifying anatomical parameters to detect the occurrence of signs of structural damage. Fluorescence parameters and total photosynthetic pigment content were analysed to evaluate the functioning of the photosynthetic machinery. Radiation did not affect percentage and rate of seed germination. Plants from irradiated seeds accomplished the crop cycle and showed a more compact habitus. Dose-depended tendencies of variations occurred in phenolic content, while other leaf anatomical parameters did not show distinct trends after irradiation. The sporadic perturbations of leaf structure, observed during the vegetative phase, after high levels of radiation were not so severe as to induce any significant alterations in photosynthetic efficiency. PMID:24883400

  9. Study on the influence of the B4C layer thickness on the neutron flux and energy distribution shape in multi-electrode ionisation chamber.

    PubMed

    Tymińska, K; Maciak, M; Ośko, J; Tulik, P; Zielczyński, M; Gryziński, M A

    2014-10-01

    A model of a multi-electrode ionisation chamber, with polypropylene electrodes coated with a thin layer of B4C was created within Monte Carlo N-Particle Transport Code (MCNPX) and Fluktuierende Kaskade (FLUKA) codes. The influence of the layer thickness on neutron absorption in B4C and on the neutron spectra in the consecutive intra-electrode gas volumes has been studied using the MCNPX and FLUKA codes. The results will be used for designing the new type of the ionisation chamber. PMID:24729596

  10. In situ analysis of Titan's tholins by Laser 2 steps Desorption Ionisation

    NASA Astrophysics Data System (ADS)

    Benilan, Y.; Carrasco, N.; Cernogora, G.; Gazeau, M.; Mahjoub, A.; Szopa, C.; Schwell, M.

    2013-12-01

    The main objective of the whole project developed in collaboration (LISA/LATMOS) is to provide a better understanding of the chemical composition of Titan aerosols laboratory analogs, called tholins, and thereby of their formation pathways. The tholins are produced in the PAMPRE reactor (French acronyme for Aerosols Microgravity Production by Reactives Plasmas) developed at LATMOS. These tholins are generated in levitation (wall effects are thus limited) in a low pressure radiofrequency plasma. Up to now, the determination of the physical and chemical properties of these tholins was achieved after their collection and ex-situ analysis by several methods. Their bulk composition was then determined but their insoluble part is still unknown. Other studies were performed after the transfer of the soluble part of the aerosols to different analytical instruments. Therefore, possible artifacts could have influenced the results. We present the SMARD (a French acronym for Mass Spectrometry of Aerosols by InfraRed Laser Desorption) program. A challenging issue of our work is to perform the soluble and unsoluble parts of PAMPRE tholins' analysis in real time and in situ. The coupling of the PAMPRE reactor to a unique instrument (Single Particle Laser Ablation Mass Spectrometry) developed at LISA should allow determining in real time and in situ the characteristics (chemical composition together with granulometry) of the nanometric aerosols. The later are introduced in the analytical instrument using an aerodynamic lens device. Their detection and aerodynamic diameter are determined using two continuous diode lasers operating at λ = 403 nm. Then, the L2DI (Laser 2 steps Desorption Ionisation) technique is used in order to access to the chemical composition of individual particles: they are vaporized using a 10 μm CO2 pulsed laser and the gas produced is then ionized by a 248 nm KrF Excimer laser. Finally, the molecular ions are analyzed by a 1 m linear time-of-flight mass

  11. Neutral and ionised gas around the post-red supergiant IRC +10 420 at AU size scales

    NASA Astrophysics Data System (ADS)

    Oudmaijer, R. D.; de Wit, W. J.

    2013-03-01

    Context. IRC +10 420 is one of the few known massive stars in rapid transition from the red supergiant phase to the Wolf-Rayet or luminous blue variable phase. Aims: The star has an ionised wind and using the Brγ line we assess the mass-loss on spatial scales of ~1 AU. Methods: We present new VLT Interferometer AMBER data which are combined with all other AMBER data present in the literature. The final dataset covers a position angle range of ~180° and baselines up to 110 m. The spectrally dispersed visibilities, differential phases and line flux are conjointly analysed and modelled. We also present the first AMBER/FINITO observations which cover a larger wavelength range and allow us to observe the Na i doublet at 2.2 μm. The data are complemented by X-Shooter data, which provide a higher spectral resolution view. Results: The Brγ emission line and the Na i doublet are both spatially resolved. After correcting the AMBER data for the fact that the lines are not spectrally resolved, we find that Brγ traces a ring with a diameter of 4.18 mas, in agreement with higher spectral resolution data. We consider a geometric model in which the Brγ emission emerges from the top and bottom rings of an hour-glass shaped structure, viewed almost pole-on. It provides satisfactory fits to most visibilities and differential phases. The fact that we detect line emission from a neutral metal like Na i within the ionised region, a very unusual occurrence, suggests the presence of a dense pseudo-photosphere. Conclusions: The ionised wind can be reproduced with a polar wind, which could well have the shape of an hour-glass. Closer in, the resolved Na i emission is found to occur on scales barely larger than the continuum. This fact and that many yellow hypergiants exhibit this comparatively rare emission hints at the presence of a "Yellow" or even "White Wall" in the Hertzsprung-Russell diagram, preventing them from visibly evolving to the blue. Based on observations at ESO, and in

  12. Rapid and simultaneous determination of polychlorinated biphenyls and their main metabolites (hydroxylated and methyl sulfonyl) by gas chromatography coupled to mass spectrometry: comparison of different ionisation modes.

    PubMed

    Castro-Puyana, M; Herrero, L; González, M J; Gómara, B

    2013-07-17

    Instrumental methods based on gas chromatography coupled to mass spectrometry (GC-MS) have been developed and compared using two different MS ionisation modes, electron impact (EI) and electron capture negative ionisation (ECNI), for the fast, quantitative and simultaneous determination of polychlorinated biphenyls (PCBs) and their main metabolites (hydroxylated PCBs, OH-PCBs, and methyl sulfone PCBs, MeSO2-PCBs). Parameters affecting chromatographic separation and MS detection were evaluated in order to achieve the highest selectivity and sensitivity for both operation modes. The analytical characteristics of the developed methods were studied and compared in terms of linear range, limits of detection (LODs), limits of quantification (LOQs), and instrumental precision (repeatability and intermediate precision). Both ionisation methods showed similar precision, being relative standard deviations (RSD, %) lower than 9% and 14% for repeatability and intermediate precision, respectively. However, better LODs (from 0.01 to 0.14 pg injected for the three families of congeners studied) were achieved using ECNI-MS as ionisation mode. The suitability of the developed method was demonstrated through their application to fish liver oil samples. PMID:23830433

  13. Investigation of colloidal graphite as a matrix for matrix-assisted laser desorption/ionisation mass spectrometry of low molecular weight analytes.

    PubMed

    Warren, Alexander D; Conway, Ulric; Arthur, Christopher J; Gates, Paul J

    2016-07-01

    The analysis of low molecular weight compounds by matrix-assisted laser desorption/ionisation mass spectrometry is problematic due to the interference and suppression of analyte ionisation by the matrices typically employed - which are themselves low molecular weight compounds. The application of colloidal graphite is demonstrated here as an easy to use matrix that can promote the ionisation of a wide range of analytes including low molecular weight organic compounds, complex natural products and inorganic complexes. Analyte ionisation with colloidal graphite is compared with traditional organic matrices along with various other sources of graphite (e.g. graphite rods and charcoal pencils). Factors such as ease of application, spectra reproducibility, spot longevity, spot-to-spot reproducibility and spot homogeneity (through single spot imaging) are explored. For some analytes, considerable matrix suppression effects are observed resulting in spectra completely devoid of matrix ions. We also report the observation of radical molecular ions [M(-●) ] in the negative ion mode, particularly with some aromatic analytes. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27434807

  14. Role of the resistivity of insulating field emitters on the energy of field-ionised and field-evaporated atoms.

    PubMed

    Arnoldi, L; Silaeva, E P; Vurpillot, F; Deconihout, B; Cadel, E; Blum, I; Vella, A

    2015-12-01

    In order to improve the accuracy of laser atom probe analyses, it is important to understand all the physical processes induced by the combination of the high electrical field and the femtosecond laser beam during field evaporation. New information can be accessed from the energy of evaporated surface atoms or field-ionised atoms of an imaging gas. In order to study the ions energy, we combine La-APT and FIM analyses in a new experimental setup equipped with electrostatic lenses. We report measurements for semiconductors and oxides and we study the influence of the illumination conditions (laser power and wavelength), the evaporation rate, the sample geometry and the tip preparation processes. The results are discussed taking into account the resistive properties of non-metallic samples and the photo-stimulated conductivity. This work clarifies the role of the laser and DC field in the energy deficit of field evaporated ions. PMID:25484362

  15. Spectroscopy of acetylene Rydberg states studied by VUV absorption and (3+1)-Resonantly Enhanced Multiphoton Ionisation

    NASA Astrophysics Data System (ADS)

    Boyé, Séverine; Campos, Andrea; Fillion, Jean-Hugues; Douin, Stéphane; Shafizadeh, Niloufar; Gauyacq, Dolores

    2004-03-01

    The ungerade ns+ nd Rydberg states of C 2H 2 converging to the ground state of the C 2H 2+ cation have been investigated in the energy range 74 000- 88 000 cm-1 by (3+1)-multiphoton ionisation (REMPI) and by VUV absorption spectroscopy at the Super-ACO synchrotron radiation facility. Both methods have allowed the selective analysis of the Rydberg transitions with rotational resolution. Mulliken's semi-united atom model, in which predissociation has been taken into account, was used to understand the relative three-photon intensities among the different electronic transitions within the same Rydberg supercomplex. Lifetimes have been evaluated and illustrate very different behaviours towards predissociation for the observed Rydberg states. To cite this article: S. Boyé et al., C. R. Physique 5 (2004).

  16. Direct atmospheric pressure chemical ionisation ion trap mass spectrometry for aroma analysis: Speed, sensitivity and resolution of isobaric compounds

    NASA Astrophysics Data System (ADS)

    Jublot, Lionel; Linforth, Robert S. T.; Taylor, Andrew J.

    2005-06-01

    Atmospheric pressure chemical ionisation (APCI) sources were developed for real time analysis of volatile release from foods using an ion trap (IT) mass spectrometer (MS). Key objectives were spectral simplicity (minimal fragmentation), response time and signal to noise ratio. The benefits of APCI-IT-MS were assessed by comparing the performance for in vivo and headspace analyses with that obtained using APCI coupled to a quadrupole mass analyser. Using MS-MS, direct APCI-IT-MS was able to differentiate mixtures of some C6 and terpene isobaric aroma compounds. Resolution could be achieved for some compounds by monitoring specific secondary ions. Direct resolution was also achieved with two of the three isobaric compounds released from chocolate with time as the sample was eaten.

  17. Matrix-assisted laser desorption/ionisation mass spectrometry imaging and its development for plant protein imaging

    PubMed Central

    2011-01-01

    Matrix-Assisted Laser Desorption/Ionisation (MALDI) mass spectrometry imaging (MSI) uses the power of high mass resolution time of flight (ToF) mass spectrometry coupled to the raster of lasers shots across the cut surface of tissues to provide new insights into the spatial distribution of biomolecules within biological tissues. The history of this technique in animals and plants is considered and the potential for analysis of proteins by this technique in plants is discussed. Protein biomarker identification from MALDI-MSI is a challenge and a number of different approaches to address this bottleneck are discussed. The technical considerations needed for MALDI-MSI are reviewed and these are presented alongside examples from our own work and a protocol for MALDI-MSI of proteins in plant samples. PMID:21726462

  18. Thermoluminescent properties of Ni and Co doped synthetic, high pressure, high temperature diamonds: application to ionising radiation dosimetry.

    PubMed

    Benabdesselam, M; Iacconi, P; Gheeraert, E; Kanda, H; Lapraz, D; Briand, D

    2002-01-01

    An investigation of the thermoluminescence (TL) properties of high pressure, high temperature (HPHT) synthetic diamond crystals grown under diluted nickel or cobalt as solvent catalysts is reported. After a study of TL properties of 6 different samples, it is shown that a crystal grown with Ni+2%Ti and annealed at 2100 K presents an intense glow peak at around 490 K. This peak is characterised by a broad emission band centred at 530 nm (2.34 eV). This crystal presents a significant, reproducible and linear TL response relative to the absorbed dose up to an X ray air kerma of 10 Gy. All these features make this material suitable for ionising radiation dosimetry. A similar study is made on another crystal grown from pure Co, and a comparative review of the results does show that for dosimetry work, Ni-containing diamonds are more appropriate than those grown from Co catalyst. PMID:12382890

  19. Excitation of low-frequency residual currents at combination frequencies of an ionising two-colour laser pulse

    NASA Astrophysics Data System (ADS)

    Vvedenskii, N. V.; Kostin, V. A.; Laryushin, I. D.; Silaev, A. A.

    2016-05-01

    We have studied the processes of excitation of low-frequency residual currents in a plasma produced through ionisation of gases by two-colour laser pulses in laser-plasma schemes for THz generation. We have developed an analytical approach that allows one to find residual currents in the case when one of the components of a two-colour pulse is weak enough. The derived analytical expressions show that the effective generation of the residual current (and hence the effective THz generation) is possible if the ratio of the frequencies in the two-colour laser pulse is close to a rational fraction with a not very big odd sum of the numerator and denominator. The results of numerical calculations (including those based on the solution of the three-dimensional time-dependent Schrödinger equation) agree well with the analytical results.

  20. Surface analysis using a new plasma assisted desorption/ionisation source for mass spectrometry in ambient air

    NASA Astrophysics Data System (ADS)

    Bowfield, A.; Barrett, D. A.; Alexander, M. R.; Ortori, C. A.; Rutten, F. M.; Salter, T. L.; Gilmore, I. S.; Bradley, J. W.

    2012-06-01

    The authors report on a modified micro-plasma assisted desorption/ionisation (PADI) device which creates plasma through the breakdown of ambient air rather than utilising an independent noble gas flow. This new micro-PADI device is used as an ion source for ambient mass spectrometry to analyse species released from the surfaces of polytetrafluoroethylene, and generic ibuprofen and paracetamol tablets through remote activation of the surface by the plasma. The mass spectra from these surfaces compare favourably to those produced by a PADI device constructed using an earlier design and confirm that the new ion source is an effective device which can be used to achieve ambient mass spectrometry with improved spatial resolution.

  1. Rapid screening of illicit additives in weight loss dietary supplements with desorption corona beam ionisation (DCBI) mass spectrometry.

    PubMed

    Wang, H; Wu, Y; Zhao, Y; Sun, W; Ding, L; Guo, B; Chen, B

    2012-08-01

    Desorption corona beam ionisation (DCBI), the relatively novel ambient mass spectrometry (MS) technique, was utilised to screen for illicit additives in weight-loss food. The five usually abused chemicals - fenfluramine, N-di-desmethyl sibutramine, N-mono-desmethyl sibutramine, sibutramine and phenolphthalein - were detected with the proposed DCBI-MS method. Fast single-sample and high-throughput analysis was demonstrated. Semi-quantification was accomplished based on peak areas in the ion chromatograms. Four illicit additives were identified and semi-quantified in commercial samples. As there was no tedious sample pre-treatment compared with conventional HPLC methods, high-throughput analysis was achieved with DCBI. The results proved that DCBI-MS is a powerful tool for the rapid screening of illicit additives in weight-loss dietary supplements. PMID:22784191

  2. Mortality and ionising radiation exposures among workers employed at the Fernald Feed Materials Production Center (1951–1985)

    PubMed Central

    Silver, Sharon R; Bertke, Stephen J; Hein, Misty Jena; Daniels, Robert D; Fleming, Donald A; Anderson, Jeri L; Pinney, Susan M; Hornung, Richard W; Tseng, Chih-Yu

    2015-01-01

    Objectives To examine mortality patterns and dose-response relations between ionising radiation and mortality outcomes of a priori interest in 6409 uranium workers employed for at least 30 days (1951–1985), and followed through 2004. Methods Cohort mortality was evaluated through standardised mortality ratios (SMR). Linear excess relative risk (ERR) regression models examined associations between cause-specific mortality and exposures to internal ionising radiation from uranium deposition, external gamma and x-ray radiation, and radon decay products, while adjusting for non-radiologic covariates. Results Person-years at risk totalled 236 568 (mean follow-up 37 years), and 43% of the cohort had died. All-cause mortality was below expectation only in salaried workers. Cancer mortality was significantly elevated in hourly males, primarily from excess lung cancer (SMR=1.25, 95% CI 1.09 to 1.42). Cancer mortality in salaried males was near expectation, but lymphohaematopoietic malignancies were significantly elevated (SMR=1.52, 95% CI 1.06 to 2.12). A positive dose-response relation was observed for intestinal cancer, with a significant elevation in the highest internal organ dose category and a significant dose-response with organ dose from internal uranium deposition (ERR=1.5 per 100 µGy, 95% CI 0.12 to 4.1). Conclusions A healthy worker effect was observed only in salaried workers. Hourly workers had excess cancer mortality compared with the US population, although there was little evidence of a dose-response trend for any cancer evaluated except intestinal cancer. The association between non-malignant respiratory disease and radiation dose observed in previous studies was not apparent, possibly due to improved exposure assessment, different outcome groupings, and extended follow-up. PMID:23322915

  3. Nucleoplasmic bridges and acrocentric chromosome associations as early markers of exposure to low levels of ionising radiation in occupationally exposed hospital workers.

    PubMed

    Caradonna, Fabio

    2015-03-01

    Ionising radiation, with the contribution of telomere shortening, induces DNA double-strand breaks that result in chromosome end fusion, nucleoplasmic bridges (NPBs) and chromosome aberrations (ChAbs) as well as dicentric chromosomes. In order to investigate the chromosomal damage induced by occupational ionising radiation at low exposure levels, and to find early markers of health hazard, peripheral lymphocytes of occupationally exposed hospital workers were cytogenetically analysed. Results showed a significant difference in the frequency of ChAbs in exposed subjects relative to controls. A significant number of NPBs between nuclei of binucleated cultured lymphocytes from exposed subjects were also observed, as well as a consistent amount of acrocentric chromosomes with associations of their short arms. Excluding confounding factors, the frequencies of all these three biological endpoints differed significantly in exposed subjects from those in controls. Because the absence of telomeres and/or their short length could be a common root for both the findings, we utilised fluorescence in situ hybridisation technique with telomeric repeat as probe to demonstrate that, in exposed subjects, chromatin of short arms of involved acrocentric chromosomes did not exhibit a telomeric shortening but appeared strongly decondensed. This finding suggests that NPBs and telomeric acrocentric association should be regarded as early markers of exposure to low levels of ionising radiation and their increase should be seen as an early warning for the health of the involved workers. PMID:25381312

  4. Evidence for a Circum-Nuclear and Ionised Absorber in the X-ray Obscured Broad Line Radio Galaxy 3C 445

    NASA Technical Reports Server (NTRS)

    Braito, V.; Reeves, J. N.; Sambruna, R. M.; Gofford, J.

    2012-01-01

    Here we present the results of a Suzaku observation of the Broad Line Radio Galaxy 3C 445. We confirm the results obtained with the previous X-ray observations which unveiled the presence of several soft X-ray emission lines and an overall X-ray emission which strongly resembles a typical Seyfert 2 despite of the optical classification as an unobscured AGN. The broad band spectrum allowed us to measure for the first time the amount of reflection (R approximately 0.9) which together with the relatively strong neutral Fe Ka emission line (EW approximately 100 eV) strongly supports a scenario where a Compton-thick mirror is present. The primary X ray continuum is strongly obscured by an absorber with a column density of NH = 2 - 3 x 10(exp 23) per square centimeter. Two possible scenarios are proposed for the absorber: a neutral partial covering or a mildly ionised absorber with an ionisation parameter log xi approximately 1.0 erg centimeter per second. A comparison with the past and more recent X-ray observations of 3C 445 performed with XMM-Newton and Chandra is presented, which provided tentative evidence that the ionised and outflowing absorber varied. We argue that the absorber is probably associated with an equatorial diskwind located within the parsec scale molecular torus.

  5. Kinematic alignment of non-interacting CALIFA galaxies. Quantifying the impact of bars on stellar and ionised gas velocity field orientations

    NASA Astrophysics Data System (ADS)

    Barrera-Ballesteros, J. K.; Falcón-Barroso, J.; García-Lorenzo, B.; van de Ven, G.; Aguerri, J. A. L.; Mendez-Abreu, J.; Spekkens, K.; Lyubenova, M.; Sánchez, S. F.; Husemann, B.; Mast, D.; García-Benito, R.; Iglesias-Paramo, J.; Del Olmo, A.; Márquez, I.; Masegosa, J.; Kehrig, C.; Marino, R. A.; Verdes-Montenegro, L.; Ziegler, B.; McIntosh, D. H.; Bland-Hawthorn, J.; Walcher, C. J.; Califa Collaboration

    2014-08-01

    We present 80 stellar and ionised gas velocity maps from the Calar Alto Legacy Integral Field Area (CALIFA) survey in order to characterise the kinematic orientation of non-interacting galaxies. The study of galaxies in isolation is a key step towards understanding how fast-external processes, such as major mergers, affect kinematic properties in galaxies. We derived the global and individual (projected approaching and receding sides) kinematic position angles (PAs) for both the stellar and ionised gas line-of-sight velocity distributions. When compared to the photometric PA, we find that morpho-kinematic differences are smaller than 22 degrees in 90% of the sample for both stellar and nebular components and that internal kinematic misalignments are generally smaller than 16 degrees. We find a tight relation between the global stellar and ionised gas kinematic PA consistent with circular-flow pattern motions in both components (~90% of the sample has differences smaller than 16 degrees). This relation also holds, generally in barred galaxies across the bar and galaxy disc scales. Our findings suggest that even in the presence of strong bars, both the stellar and the gaseous components tend to follow the gravitational potential of the disc. As a result, kinematic orientation can be used to assess the degree of external distortions in interacting galaxies. Appendices are available in electronic form at http://www.aanda.org

  6. Determination of agrochemical compounds in soya plants by imaging matrix-assisted laser desorption/ionisation mass spectrometry.

    PubMed

    Mullen, Alexander K; Clench, Malcolm R; Crosland, Susan; Sharples, Kate R

    2005-01-01

    Detection and imaging of the herbicide mesotrione (2-(4-mesyl-2-nitrobenzoyl)cyclohexane-1,3-dione) and the fungicide azoxystrobin (methyl (E)-2-{2-[6-(2-cyanophenoxy)pyrimidin-4-yloxy]phenyl}-3-methoxyacrylate), on the surface of the soya leaf, and the detection and imaging of azoxystrobin inside the stem of the soya plant, have been achieved using matrix-assisted laser desorption/ionisation quadrupole time-of-flight mass spectrometry. In leaf analysis experiments, the two pesticides were deposited onto the surface of individual soya leaves on growing plants. The soya leaves were removed and prepared for direct and indirect (following blotting onto matrix-coated cellulose membranes) imaging analysis at different periods after initial pesticide application. In stem analysis experiments, azoxystrobin was added to the nutrient solution of a soya plant growing in a hydroponics system. The plant was left for 48 h, and then horizontal and vertical stem sections were prepared for direct imaging analysis. The images obtained demonstrate the applicability of MALDI imaging to the detection and imaging of small organic compounds in plant tissue and further extend the analytical repertoire of the versatile MALDI technique. PMID:16106343

  7. Determination of sulfonamides by packed column supercritical fluid chromatography with atmospheric pressure chemical ionisation mass spectrometric detection.

    PubMed

    Dost, K; Jones, D C; Davidson, G

    2000-07-01

    Sulfonamide antibiotics are widely used to prevent bacterial infections in livestock, and residues are commonly found in milk and meat. Packed column supercritical fluid chromatography (pSFC) with detection using ultra violet (UV) and atmospheric pressure chemical ionisation (APCI) mass spectrometry (MS) provides a versatile method for the detection and quantification of six major sulfonamides. The APCI mass spectra for all the sulfonamides consisted of protonated molecules at low cone voltages. Increasing the cone voltage led to informative fragmentation patterns, which provided structural information for identification purposes. The pSFC-APCI-MS technique was shown to be linear (r2 > or = 0.999) over the concentration range 0.1-50 micrograms ml-1 using total ion current. The precision and the accuracy of the system and validation of sample preparation are acceptable, with RSD < 2% and relative error 8%. Selected ion monitoring gave detection limits as follows: sulfadiazine 41, sulfamethoxazole 45, sulfamerazine 47, sulfamethizole 59, sulfamethazine 181 and sulfadimethoxine 96 micrograms l-1, which are lower than the amounts permitted in milk products. The APCI pSFC-MS system was shown to have a high degree of reproducibility. The technique was then applied to determine the above sulfonamides in milk. The results obtained show that there are no matrix effects from the milk and that the detection limits remained as stated for the standard solutions. PMID:10984919

  8. Identification of synthetic dyes in early colour photographs using capillary electrophoresis and electrospray ionisation-mass spectrometry.

    PubMed

    López-Montes, Ana Ma; Dupont, Anne-Laurence; Desmazières, Bernard; Lavédrine, Bertrand

    2013-09-30

    Capillary electrophoresis with photodiode array detection (CE-PDA) and with electrospray ionisation-mass spectrometry (CE-ESI-MS) was used for the separation and the identification of 23 synthetic organic dyes, among those used in early 20th century colour photographs such as autochromes. Both cationic and anionic dyes could be separated within 15min using a single CE-PDA method. The method was used as the basis to develop a CE-ESI-MS methodology through the optimisation of the relevant ESI and MS parameters. Sheath liquid composition, nebulising gas pressure, drying gas flow rate and drying gas temperature were found to influence the sensitivity of the detection. These parameters were optimised in positive and negative ion modes for cationic dyes and anionic dyes, respectively. The two analyses could be carried out successively on a single sample. In view of the application to cultural heritage objects, the CE-ESI-MS analytical procedure was applied to identify the dyes in a Filmcolor artefact, late version of the autochrome. The results complemented and enhanced current knowledge as four cationic dyes and three anionic dyes were identified. Four additional dyes are proposed as possibly present as traces. PMID:23953463

  9. Observations of a groove in the interplanetary Lyman alpha pattern as the signature of enhanced ionisation in the neutral sheet

    NASA Astrophysics Data System (ADS)

    Bertaux, J. L.; Quemerais, E.; Lallement, R.; Summanen, T.; Kyrola, E.

    1995-06-01

    We report several observations of the Lyman alpha interplanetary emission recorded by a photometer flown in 1976-1977 on board the Soviet spacecraft Prognoz-5 and Prognoz-6. Several scans made in a plane perpendicular to the sun were cutting through the maximum emission region. where the interstellar hydrogen is approaching nearest to the sun (upwind region). On each of these scans is observed a dip in the intensity curve near the ecliptic plane. about 30 deg wide and approximately equals 10% deep. They reveal the presence of a new feature of the interplanetary emission. a 'groove' aligned approximately with the ecliptic plane. This groove is present only near the upwind direction, and is interpreted as the result of enhanced ionisation of interstellar H by charge-exchange with the solar wind in a sheet of approximately 30 deg around the average position of the neutral sheet at this time of solar this Lyman alpha groove is a prime target for future observations with SWAN experiment on SOHO.

  10. Observations of a groove in the interplanetary Lyman alpha pattern as the signature of enhanced ionisation in the neutral sheet

    NASA Technical Reports Server (NTRS)

    Bertaux, J. L.; Quemerais, E.; Lallement, R.; Summanen, T.; Kyrola, E.

    1995-01-01

    We report several observations of the Lyman alpha interplanetary emission recorded by a photometer flown in 1976-1977 on board the Soviet spacecraft Prognoz-5 and Prognoz-6. Several scans made in a plane perpendicular to the sun were cutting through the maximum emission region. where the interstellar hydrogen is approaching nearest to the sun (upwind region). On each of these scans is observed a dip in the intensity curve near the ecliptic plane. about 30 deg wide and approximately equals 10% deep. They reveal the presence of a new feature of the interplanetary emission. a 'groove' aligned approximately with the ecliptic plane. This groove is present only near the upwind direction, and is interpreted as the result of enhanced ionisation of interstellar H by charge-exchange with the solar wind in a sheet of approximately 30 deg around the average position of the neutral sheet at this time of solar this Lyman alpha groove is a prime target for future observations with SWAN experiment on SOHO.

  11. Thin-layer chromatography-matrix-assisted laser desorption ionisation-time-of-flight mass spectrometry using particle suspension matrices.

    PubMed

    Crecelius, Anna; Clench, Malcolm R; Richards, Don S; Parr, Vic

    2002-06-01

    Particle suspension matrices have been successfully utilized for the analysis of tetracycline antibiotics by thin-layer chromatography-matrix-assisted laser desorption ionisation-time-of-flight mass spectrometry (TLC-MALDI-TOF-MS). Particles of different materials and sizes have been investigated (Co-UFP, TiN, TiO2, Graphite and Silicon) by applying particle suspensions to eluted TLC plates. Mass spectra and mass chromatograms have been recorded directly from the TLC plates. Strong cationization by sodium and potassium was obtained in the positive ion mode, with [M+Na-NH3]+ ions being the predominant signals. The TLC-MALDI mass spectra recorded from graphite suspensions showed the lowest background noise and the highest peak intensities from the range of suspension matrices studied. The mass accuracy from graphite films was improved by adding the peptide Phe-Phe to the graphite suspensions. This allowed internal recalibration of the TLC-MALDI mass spectra acquired during a run. One major potential advantage of TLC-MALDI-TOF-MS has been demonstrated in the analysis of chlortetracycline and tetracycline in a mixture of oxytetracycline, chlortetracycline, tetracycline and minocycline. Examination of the TLC plate prior to MALDI analysis showed only an unresolved spot for chlortetracycline and tetracycline. However by investigation of the MALDI mass spectra and plotting of single ion chromatograms separate peaks for chlortetracycline and tetracycline could be obtained. PMID:12134822

  12. Analysis of organophosphate flame retardants and plasticisers in water by isotope dilution gas chromatography-electron ionisation tandem mass spectrometry.

    PubMed

    Teo, Tiffany L L; McDonald, James A; Coleman, Heather M; Khan, Stuart J

    2015-10-01

    The widespread use of organophosphate flame retardants (PFRs) in commercial products have led to their increased presence in the environment. In this study, a rapid and reliable analytical method was developed for the analysis of five PFRs in water using gas chromatography tandem mass spectrometry (GC-MS/MS) with electron ionisation (EI) and a run time of 13 min. The PFRs investigated were tributyl phosphate (TBP), tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCPP), tris(1,3-dichloro-2-propyl) phosphate (TDCP) and triphenyl phosphate (TPP). Solid phase extraction (SPE) was undertaken to extract and concentrate target analytes from aqueous matrices. All water samples were extracted from a volume of 500 mL. Isotopically labelled compounds were used to account for analytical variability and for accurate quantification by isotope dilution. Method recoveries for all compounds were above 80% in all tested water samples. Method detection limits for all target analytes ranged from 0.3 to 24 ng/L in ultrapure water, tap water, seawater, surface water, secondary effluent and swimming pool water. Validation of this method confirmed satisfactory method stability with less than 1% coefficients of variation, verifying that this approach produced good reproducibility. PMID:26078137

  13. Characterisation of a proposed internet synthesis of N,N-dimethyltryptamine using liquid chromatography/electrospray ionisation tandem mass spectrometry.

    PubMed

    Martins, Cláudia P B; Freeman, Sally; Alder, John F; Brandt, Simon D

    2009-08-14

    The psychoactive properties of N,N-dimethyltryptamine (DMT) are known to induce altered states of consciousness in humans. These properties attract great interest from clinical, neuroscientific, clandestine and forensic communities. The Breath of Hope Synthesis was reported on an internet website as a convenient two-step methodology for the preparation of DMT. The analytical characterisation of the first stage was the subject of previous publications by the authors and involved the thermal decarboxylation of tryptophan and the formation of tryptamine. The present study reports on the characterisation of the second step of this procedure which was based on the methylation of tryptamine. This employed methyl iodide and benzyltriethylammonium chloride/sodium hydroxide as a phase transfer catalyst. The reaction product was characterised by liquid chromatography/electrospray ionisation tandem mass spectrometry and orthogonal acceleration time-of-flight mass spectrometry. Quantitative evaluation was carried out in positive multiple reaction monitoring mode (MRM), which included synthesis of the identified reaction products. MRM screening of the product did not lead to the detection of DMT. Instead, 11.1% tryptamine starting material, 21.0% N,N,N-trimethyltryptammonium iodide (TMT) and 47.4% 1-N-methyl-TMT were detected. A 0.5% trace of the monomethylated N-methyltryptamine was also detected. This study demonstrated the impact on product purity of doubtful synthetic methodologies discussed on the internet. PMID:19592003

  14. Rapid assignment of malting barley varieties by matrix-assisted laser desorption-ionisation - Time-of-flight mass spectrometry.

    PubMed

    Šedo, Ondrej; Kořán, Michal; Jakešová, Michaela; Mikulíková, Renata; Boháč, Michal; Zdráhal, Zbyněk

    2016-09-01

    A method for discriminating malting barley varieties based on direct matrix-assisted laser desorption-ionisation - time-of-flight mass spectrometry (MALDI-TOF MS) fingerprinting of proteins was developed. Signals corresponding to hordeins were obtained by simple mixing of powdered barley grain with a MALDI matrix solution containing 12.5mgmL(-1) of ferulic acid in an acetonitrile:water:formic acid 50:33:17 v/v/v mixture. Compared to previous attempts at MALDI-TOF mass spectrometric analysis of barley proteins, the extraction and fractionation steps were practically omitted, resulting in a significant reduction in analytical time and costs. The discriminatory power was examined on twenty malting barley varieties and the practicability of the method was tested on sixty barley samples acquired from Pilsner Urquell Brewery. The method is proposed as a rapid tool for variety assignment and purity determination of malting barley that may replace gel electrophoresis currently used for this purpose. PMID:27041307

  15. Study of the uncertainty in estimation of the exposure of non-human biota to ionising radiation.

    PubMed

    Avila, R; Beresford, N A; Agüero, A; Broed, R; Brown, J; Iospje, M; Robles, B; Suañez, A

    2004-12-01

    Uncertainty in estimations of the exposure of non-human biota to ionising radiation may arise from a number of sources including values of the model parameters, empirical data, measurement errors and biases in the sampling. The significance of the overall uncertainty of an exposure assessment will depend on how the estimated dose compares with reference doses used for risk characterisation. In this paper, we present the results of a study of the uncertainty in estimation of the exposure of non-human biota using some of the models and parameters recommended in the FASSET methodology. The study was carried out for semi-natural terrestrial, agricultural and marine ecosystems, and for four radionuclides (137Cs, 239Pu, 129I and 237Np). The parameters of the radionuclide transfer models showed the highest sensitivity and contributed the most to the uncertainty in the predictions of doses to biota. The most important ones were related to the bioavailability and mobility of radionuclides in the environment, for example soil-to-plant transfer factors, the bioaccumulation factors for marine biota and the gut uptake fraction for terrestrial mammals. In contrast, the dose conversion coefficients showed low sensitivity and contributed little to the overall uncertainty. Radiobiological effectiveness contributed to the overall uncertainty of the dose estimations for alpha emitters although to a lesser degree than a number of transfer model parameters. PMID:15700701

  16. Characterisation of an inexpensive sonic spray ionisation source using laser-induced fluorescence imaging and mass spectrometry.

    PubMed

    Stindt, Arne; Warschat, Carsten; Bierstedt, Andreas; Panne, Ulrich; Riedel, Jens

    2014-01-01

    A commercially available airbrush gun as a new source for spray ionisation is presented. It is best operated employing moderate stagnation pressures, resulting in a sonic gas flow. A mass spectrometric investigation on the amino acid Lysine and several peptides reveals that this inexpensive approach results in reproducible mass spectra. The ion patterns strongly resemble the results from other studies obtained with custom-made sonic spray vaporisers. The patterns also resemble the mass spectra recorded with electrospray devices. For a better understanding of the vaporisation process, the mass spectrometry experiments are accompanied by laser-induced fluorescence experiments. Inverse Abel Transform of the obtained fluorescence maps allows the determination of the full three-dimensional distribution of the spray cone. Furthermore, via exploitation of the solvatochromism of the used dye the solvation-state distribution can be visualised. In addition, expansion parameters, such as droplet size and velocity, are obtained by laser stroboscopy. The experiments demonstrate that the analyte hardly desolvates throughout the expansion. This indicates a subsequent vaporisation of the residual solvent in the intermediate pressure region of the mass spectrometer. PMID:24881452

  17. Unrepairable DNA double-strand breaks that are generated by ionising radiation determine the fate of normal human cells.

    PubMed

    Noda, Asao; Hirai, Yuko; Hamasaki, Kanya; Mitani, Hiroshi; Nakamura, Nori; Kodama, Yoshiaki

    2012-11-15

    After an exposure to ionising radiation, cells can quickly repair damage to their genomes; however, a few unrepairable DNA double-strand breaks (DSBs) emerge in the nucleus in a prolonged culture and perpetuate as long as the culture continues. These DSBs may be retained forever in cells such as non-dividing ageing tissues, which are resistant to apoptosis. We show that such unrepairable DSBs, which had been advocated by the classical target theory as the 'radiation hit', could account for permanent growth arrest and premature senescence. The unrepairable DSBs build up with repeated irradiation, which accounts for an accumulated dose. Because these DSBs tend to be paired, we propose that the untethered and 'torn-off' molecular structures at the broken ends of the DNA result in an alteration of chromatin structure, which protects the ends of the DNA from genomic catastrophe. Such biochemical responses are important for cell survival but may cause gradual tissue malfunction, which could lead to the late effects of radiation exposure. Thus, understanding the biology of unrepairable damage will provide new insights into the long-term effects of radiation. PMID:22899723

  18. Radiation in the workplace-a review of studies of the risks of occupational exposure to ionising radiation.

    PubMed

    Wakeford, Richard

    2009-06-01

    Many individuals are, or have been, exposed to ionising radiation in the course of their work and the epidemiological study of occupationally irradiated groups offers an important opportunity to complement the estimates of risks to health resulting from exposure to radiation that are obtained from other populations, such as the Japanese survivors of the atomic bombings of Hiroshima and Nagasaki in 1945. Moreover, workplace exposure to radiation usually involves irradiation conditions that are of direct relevance to the principal concern of radiological protection: protracted exposure to low level radiation. Further, some workers have been exposed to radioactive material that has been inadvertently taken into the body, and the study of these groups leads to risk estimates derived directly from the experience of those irradiated by these 'internal emitters', intakes of alpha-particle-emitters being of particular interest. Workforces that have been the subject of epidemiological study include medical staff, aircrews, radium dial luminisers, underground hard-rock miners, Chernobyl clean-up workers, nuclear weapons test participants and nuclear industry workers. The first solid epidemiological evidence of the stochastic effects of irradiation came from a study of occupational exposure to medical x-rays that was reported in 1944, which demonstrated a large excess risk of leukaemia among US radiologists; but the general lack of dose records for early medical staff who tended to experience the highest exposures hampers the derivation of risks per unit dose received by medical workers. The instrument dial luminisers who inadvertently ingested large amounts of radium-based paint and underground hard-rock miners who inhaled large quantities of radon and its decay products suffered markedly raised excess risks of, respectively, bone and lung cancers; the miner studies have provided standard risk estimates for radon-induced lung cancer. The large numbers of nuclear industry

  19. A derivatisation and liquid chromatography/electrospray ionisation multistage mass spectrometry method for the characterisation of naphthenic acids.

    PubMed

    Smith, B E; Rowland, S J

    2008-12-01

    Naphthenic acids (NAs) are partially uncharacterised complex mixtures of carboxylic acids, resulting from the microbial oxidation of petroleum hydrocarbons. They are associated with the fouling of pipelines and process equipment in oil production and with corrosion in oil refineries. As by-products of the rapidly expanding oil (tar) sands industries, NAs are also pollutants and have proved to be toxic to a range of organisms. They also have important beneficial uses as fungicides, tyre additives and, paradoxically, also in the manufacture of corrosion inhibitors. These features make the characterisation of NAs an important goal for analytical chemists. Here we describe the synthesis of amide derivatives of NAs for characterisation by liquid chromatography/electrospray ionisation multistage mass spectrometry (LC/ESI-MS(n)). The method was applied to commercially available carboxylic acids, novel synthetic NAs, commercial NAs refined from crude oils, crude oil NAs and Athabasca oil sands NAs. In addition to confirming the number of alicyclic rings and length of alkyl side chain substituents (confirming information from existing methods), the MS(n) results provided further structural information. Most important of these was the finding that bi- to polycyclic acids containing ethanoate side chains, in addition to alkyl substituents, were widespread amongst the oil and oil sands NAs. The latter NAs are known end members of the beta-oxidation of NAs with even carbon number alkanoate chains. Since such NA mixtures are toxic, they should be targets for bioremediation. Bioremediation of NAs can also be monitored better by application of the methods described herein. PMID:18988206

  20. The formation and evolution of reconnection-driven, slow-mode shocks in a partially ionised plasma

    NASA Astrophysics Data System (ADS)

    Hillier, A.; Takasao, S.; Nakamura, N.

    2016-06-01

    The role of slow-mode magnetohydrodynamic (MHD) shocks in magnetic reconnection is of great importance for energy conversion and transport, but in many astrophysical plasmas the plasma is not fully ionised. In this paper, we use numerical simulations to investigate the role of collisional coupling between a proton-electron, charge-neutral fluid and a neutral hydrogen fluid for the one-dimensional (1D) Riemann problem initiated in a constant pressure and density background state by a discontinuity in the magnetic field. This system, in the MHD limit, is characterised by two waves. The first is a fast-mode rarefaction wave that drives a flow towards a slow-mode MHD shock wave. The system evolves through four stages: initiation, weak coupling, intermediate coupling, and a quasi-steady state. The initial stages are characterised by an over-pressured neutral region that expands with characteristics of a blast wave. In the later stages, the system tends towards a self-similar solution where the main drift velocity is concentrated in the thin region of the shock front. Because of the nature of the system, the neutral fluid is overpressured by the shock when compared to a purely hydrodynamic shock, which results in the neutral fluid expanding to form the shock precursor. Once it has formed, the thickness of the shock front is proportional to ξ i-1.2 , which is a smaller exponent than would be naively expected from simple scaling arguments. One interesting result is that the shock front is a continuous transition of the physical variables of subsonic velocity upstream of the shock front (a c-shock) to a sharp jump in the physical variables followed by a relaxation to the downstream values for supersonic upstream velocity (a j-shock). The frictional heating that results from the velocity drift across the shock front can amount to ~2 per cent of the reference magnetic energy.

  1. Considerations on the modelling and optimisation of resolution of ionisable compounds in extended pH-range columns.

    PubMed

    Torres-Lapasió, J R; García-Alvarez-Coque, M C; Bosch, E; Rosés, M

    2005-09-30

    The problems associated to the modelling and optimisation of the chromatographic resolution of mixtures involving ionisable solutes at varying pH and acetonitrile content are discussed. Several retention models that separate the contributions of solute, column and stationary phase, were used. The retention was predicted with low errors in large pH domains (2-12), which was an essential requirement to face the optimisation of resolution. The selected mixture was particularly problematic under the viewpoint of resolution, owing to the excessively diverse acid-base behaviour of solutes. This variety led to sudden drops in retention at different pH for each solute, yielding numerous peak crossing, which made finding shared regions of high resolution especially difficult. Conventional resolution diagrams for these situations are scarcely informative, since both the overall and the worst elementary resolutions drop to zero if at least two compounds remain overlapped, even when all the others are baseline resolved. A new chromatographic objective function is proposed to address this drawback. This function, called "limiting peak count", is based on the limiting peak purity concept, and measures the success in the resolution focusing on the resolved solutes, in contrast to conventional resolution assessments that attend mainly to the least resolved solutes. Limiting peak count yields the same result as conventional assessments when full resolution is possible, but it is also able to discriminate the maximal resolving power in low-resolution situations. It offers a different perspective to that given by the complementary mobile phases approach, and the computation is far simpler. PMID:16130785

  2. Determination of pharmaceutical compounds in skin by imaging matrix-assisted laser desorption/ionisation mass spectrometry.

    PubMed

    Bunch, Josephine; Clench, Malcolm R; Richards, Don S

    2004-01-01

    Matrix-assisted laser desorption/ionisation (MALDI) quadrupole time-of-flight mass spectrometry (Q-TOFMS) has been used to detect and image the distribution of a xenobiotic substance in skin. Porcine epidermal tissue was treated with 'Nizoral', a medicated shampoo containing ketoconazole (+/-)-1-acetyl-4-[p-[[(2R,4S)-2-(2,4-dichlorophenyl)-2-(imidazol-1-ylmethyl)-1,3-dioxolan-4-yl]methoxy]phenyl]piperazine) as active ingredient. Following incubation for 1 h at 37 degrees C all excess formulation was washed from the surface. A cross-section of the drug-treated tissue was then blotted onto a cellulose membrane, precoated in matrix (alpha-cyano-4-hydroxycinnamic acid (CHCA)), by airspray deposition. In separate experiments the tissue surface was treated with Nizoral within a triangular former, and subsequently blotted onto a matrix-coated membrane. Sample membranes were then mounted into the recess of specialised MALDI targets with adhesive tape. All samples were analysed by MALDI-TOFMS using an Applied Biosystem 'Q-star Pulsar i' hybrid Q-TOF mass spectrometer fitted with an orthagonal MALDI ion source and imaging software. Detection of the protonated molecule was readily achievable by this technique. Treatment of the tissue within a template gave rise to images depicting the expected distribution of the drug, demonstrating that this technique is capable of producing spatially useful data. Ion images demonstrating the permeation of the applied compound into the skin were achieved by imaging a cross-sectional imprint of treated tissue. A calibration graph for the determination of ketoconazole was prepared using the sodium adduct of the matrix ion as an internal standard. This enabled construction of a quantitative profile of drug in skin. Conventional haematoxylin and eosin staining and microscopy methods were employed to obtain a histological image of the porcine epidermal tissue. Superimposing the mass spectrometric and histological images appeared to indicate drug

  3. The long-term effects of acute exposure to ionising radiation on survival and fertility in Daphnia magna.

    PubMed

    Sarapultseva, Elena I; Dubrova, Yuri E

    2016-10-01

    The results of recent studies have provided strong evidence for the transgenerational effects of parental exposure to ionising radiation and chemical mutagens. However, the transgenerational effects of parental exposure on survival and fertility remain poorly understood. To establish whether parental irradiation can affect the survival and fertility of directly exposed organisms and their offspring, crustacean Daphnia magna were given 10, 100, 1000 and 10,000mGy of acute γ-rays. Exposure to 1000 and 10,000mGy significantly compromised the viability of irradiated Daphnia and their first-generation progeny, but did not affect the second-generation progeny. The fertility of F0 and F1Daphnia gradually declined with the dose of parental exposure and significantly decreased at dose of 100mGy and at higher doses. The effects of parental irradiation on the number of broods were only observed among the F0Daphnia exposed to 1000 and 10,000mGy, whereas the brood size was equally affected in the two consecutive generations. In contrast, the F2 total fertility was compromised only among progeny of parents that received the highest dose of 10,000mGy. We propose that the decreased fertility observed among the F2 progeny of parents exposed to 10,000mGy is attributed to transgenerational effects of parental irradiation. Our results also indicate a substantial recovery of the F2 progeny of irradiated F0Daphnia exposed to the lower doses of acute γ-rays. PMID:27288911

  4. Quantitative analysis of surfactant deposits on human skin by liquid chromatography/electrospray ionisation tandem mass spectrometry.

    PubMed

    Massey, Karen A; Snelling, Anna M; Nicolaou, Anna

    2010-05-15

    Surfactants are commonly used as cleansing agents and yet there are concerns that they may also have a role in skin irritation. The lack of suitable methods for the quantitative and qualitative analysis of surfactant deposition on skin has hindered the in-depth investigation of such effects. Here, we report the application of reversed-phase liquid chromatography/electrospray ionisation tandem mass spectrometry (LC/ESI-MS/MS) assays for two surfactants commonly used in consumer products, namely sodium lauryl ether sulfate (SLES) and laurylamidopropyl betaine (LAPB), to a baseline study aiming to assess deposition levels on human skin. The linearity of the assays was established at 3-20 ng, with coefficient of variation below 5%. The detection limits were 100 pg for LAPB and 1 ng for SLES; quantitation limits were 500 pg for LAPB and 2.5 ng for SLES. The baseline study was conducted using a panel of 40 healthy volunteers. Skin extract samples were taken in triplicate from forearms, using ethanol. SLES was detected on most volunteers, with 75% of them having SLES deposits in the range of 100-600 ng/cm(2). LAPB was detected on the skin of all volunteers with 85% of them having deposit levels within the concentration range of 1-100 ng/cm(2). These results demonstrate the extent to which commonly used surfactants remain on the skin during the day. The analytical methods reported here can be applied to the investigation of surfactants in relation to general skin condition and to the development and optimisation of new consumer wash products. PMID:20391611

  5. Multi-residue analysis of pesticides in traditional Chinese medicines using gas chromatography-negative chemical ionisation tandem mass spectrometry.

    PubMed

    Nie, Jing; Miao, Shui; Lehotay, Steven J; Li, Wen-Ting; Zhou, Heng; Mao, Xiu-Hong; Lu, Ji-Wei; Lan, Lan; Ji, Shen

    2015-01-01

    In this study, a residue analysis method for the simultaneous determination of 107 pesticides in traditional Chinese medicines (TCMs), Angelica sinensis, A. dahurica, Leonurus heterophyllus Sweet, Pogostemon cablin and Lonicera japonica Thunb., was developed using gas chromatography coupled with tandem mass spectrometry in negative chemical ionisation mode (GC-NCI-MS/MS). NCI has advantages of high sensitivity and selectivity to chemicals with electron-withdrawing groups, and yields low background interference. For sample preparation, QuEChERS (quick, easy, cheap, effective, rugged and safe) was applied. Due to the unique characteristics of TCMs, the clean-up step was optimised by adjusting amounts of primary secondary amine, C18, graphitised carbon black and silica sorbents. Validation was mainly performed by determining analyte recoveries at four different spiking concentrations of 10, 50, 100 and 200 ng g(-1), with seven replicates at each concentration. Method trueness, precision, linearity of calibration curves, lowest calibrated levels (LCLs) and matrix effects were determined to demonstrate method and instrument performance. Among the 107 pesticides tested, approximately 80% gave recoveries from 80% to 110% and < 10% relative standard deviation (RSD). The LCLs for nearly all pesticides were 5 ng g(-1), and as low as 0.1 ng g(-1) for dichlofenthion, endosulfan sulphate, flumetralin, isofenphos-methyl, methyl-pentachlorophenyl sulphide and trifluralin. The results indicate that GC-NCI-MS/MS is an excellent technique for quantitative and qualitative analysis of targeted GC-amenable pesticides at ultra-trace levels, especially in complex matrices such as TCMs. PMID:26125677

  6. Fragmentation, auto-modification and post ionisation proton bound dimer ion formation: the differential mobility spectrometry of low molecular weight alcohols.

    PubMed

    Ruszkiewicz, D M; Thomas, C L P; Eiceman, G A

    2016-08-01

    Differential mobility spectrometry (DMS) is currently being used for environmental monitoring of space craft atmospheres and has been proposed for the rapid assessment of patients at accident and emergency receptions. Three studies investigated hitherto undescribed complexity in the DMS spectra of methanol, ethanol, propan-1-ol and butan-1-ol product ions formed from a (63)Ni ionisation source. 54 000 DMS spectra obtained over a concentration range of 0.01 mg m(-3)(g) to 1.80 g m(-3)(g) revealed the phenomenon of auto-modification of the product ions. This occurred when the neutral vapour concentration exceeded the level required to induce a neutral-ion collision during the low field portion of the dispersion field waveform. Further, post-ionisation cluster-ion formation or protonated monomer/proton bound dimer inter-conversion within the ion-filter was indicated by apparent shifts in the values of the protonated monomer compensation field maximum; indicative of post-ionisation conversion of the protonated monomer to a proton-bound dimer. APCI-DMS-quadrupole mass spectrometry studies enabled the ion dissociation products from dispersion-field heating to be monitored and product ion fragmentation relationships to be proposed. Methanol was not observed to dissociate, while propan-1-ol and butan-1-ol underwent dissociation reactions consistent with dehydration processes that led ultimately to the generation of what is tentatively assigned as a cyclo-C3H3(+) ion (m/z 39) and hydrated protons. Studies of the interaction of ion filter temperature with dispersion-field heating of product ions isolated dissociation/fragmentation product ions that have not been previously described in DMS. The implications of these combined findings with regard to data sharing and data interpretation were highlighted. PMID:27227997

  7. Mysteries of LiF TLD response following high ionisation density irradiation: nanodosimetry and track structure theory, dose response and glow curve shapes

    PubMed Central

    Horowitz, Y.; Fuks, E.; Datz, H.; Oster, L.; Livingstone, J.; Rosenfeld, A.

    2011-01-01

    Three outstanding effects of ionisation density on the thermoluminescence (TL) mechanisms giving rise to the glow peaks of LiF:Mg,Ti (TLD-100) are currently under investigation: (1) the dependence of the heavy charged particle (HCP) relative efficiency with increasing ionisation density and the effectiveness of its modelling by track structure theory (TST), (2) the behaviour of the TL efficiency, f(D), as a function of photon energy and dose. These studies are intended to promote the development of a firm theoretical basis for the evaluation of relative TL efficiencies to assist in their application in mixed radiation fields. And (3) the shape of composite peak 5 in the glow curve for various HCP types and energies and following high-dose electron irradiation, i.e. the ratio of the intensity of peak 5a to peak 5. Peak 5a is a low-temperature satellite of peak 5 arising from electron-hole capture in a spatially correlated trapping centre/luminescent centre (TC/LC) complex that has been suggested to possess a potential as a solid-state nanodosemeter due to the preferential electron/hole population of the TC/LC at high ionisation density. It is concluded that (1) the predictions of TST are very strongly dependent on the choice of photon energy used in the determination of f(D); (2) modified TST employing calculated values of f(D) at 2 keV is in agreement with 5-MeV alpha particle experimental results for composite peak 5 but underestimates the 1.5-MeV proton relative efficiencies. Both the proton and alpha particle relative TL efficiencies of the high-temperature TL (HTTL) peaks 7 and 8 are underestimated by an order of magnitude suggesting that the HTTL efficiencies are affected by other factors in addition to radial electron dose; (3) the dose–response supralinearity of peaks 7 and 8 change rapidly with photon energy: this behaviour is explained in the framework of the unified interaction model as due to a very strong dependence on photon energy of the relative

  8. Mysteries of LiF TLD response following high ionisation density irradiation: nanodosimetry and track structure theory, dose response and glow curve shapes.

    PubMed

    Horowitz, Y; Fuks, E; Datz, H; Oster, L; Livingstone, J; Rosenfeld, A

    2011-06-01

    Three outstanding effects of ionisation density on the thermoluminescence (TL) mechanisms giving rise to the glow peaks of LiF:Mg,Ti (TLD-100) are currently under investigation: (1) the dependence of the heavy charged particle (HCP) relative efficiency with increasing ionisation density and the effectiveness of its modelling by track structure theory (TST), (2) the behaviour of the TL efficiency, f(D), as a function of photon energy and dose. These studies are intended to promote the development of a firm theoretical basis for the evaluation of relative TL efficiencies to assist in their application in mixed radiation fields. And (3) the shape of composite peak 5 in the glow curve for various HCP types and energies and following high-dose electron irradiation, i.e. the ratio of the intensity of peak 5a to peak 5. Peak 5a is a low-temperature satellite of peak 5 arising from electron-hole capture in a spatially correlated trapping centre/luminescent centre (TC/LC) complex that has been suggested to possess a potential as a solid-state nanodosemeter due to the preferential electron/hole population of the TC/LC at high ionisation density. It is concluded that (1) the predictions of TST are very strongly dependent on the choice of photon energy used in the determination of f(D); (2) modified TST employing calculated values of f(D) at 2 keV is in agreement with 5-MeV alpha particle experimental results for composite peak 5 but underestimates the 1.5-MeV proton relative efficiencies. Both the proton and alpha particle relative TL efficiencies of the high-temperature TL (HTTL) peaks 7 and 8 are underestimated by an order of magnitude suggesting that the HTTL efficiencies are affected by other factors in addition to radial electron dose; (3) the dose-response supralinearity of peaks 7 and 8 change rapidly with photon energy: this behaviour is explained in the framework of the unified interaction model as due to a very strong dependence on photon energy of the relative

  9. Identification of main corticosteroids as illegal feed additives in milk replacers by liquid chromatography-atmospheric pressure chemical ionisation mass spectrometry.

    PubMed

    Fiori, M; Pierdominici, E; Longo, F; Brambilla, G

    1998-05-22

    Corticosteroids were proposed as growth promoting agents to improve commercial quality of meat. We developed a liquid chromatography-atmospheric pressure chemical ionisation mass spectrometry (LC-APCI-MS) method able to identify the presence in milk replacers, when given by mouth, of dexamethasone, betamethasone, flumethasone, triamcinolone, predinisotone, prednisolone, methylprednisolone, fludrocortisone and beclomethasone, at levels in the range of 20-100 ppb. C18 solid-phase extraction, LC-RP C8 column separation, data acquisition (positive ions) in the scan range m/z 200-550 allowed us to differentiate and identify compounds by protonated molecules, their methanolic adducts and fragmentation patterns. PMID:9646497

  10. [Low dose ionising radiation and cancer: findings and methods. Report of a meeting and consequences for Switzerland].

    PubMed

    Schüler, G; Gutzwiller, F

    1991-01-01

    Today's society is concerned about the dangers of ionising radiation, especially in the aftermath of Chernobyl. On the other hand, there exists a widespread lack of understanding radiation biology and radioepidemiology--the very sciences which provide the data from which today's risk estimates have been derived. The papers in this issue of the Journal were presented at a workshop on "Low level radiation and cancer: data and methods" held on 10th-11th December in Feuisberg, near Zurich. The meeting was organised by the Institute of Social and Preventive Medicine of the University of Zurich under the auspices of the Swiss Federal Office of Public Health. Its aims were threefold. First, to give an introduction to some basic facts and methodological issues in radiation physics, biology and epidemiology. Secondly, to give an overview of the availability of data for radioepidemiological research in Switzerland and, thirdly, to evaluate possible research strategies in this country. A list of some notions and units commonly used in the radiation sciences serves an an introduction to the field (G. Schüler et al.). In using units and notions it is important to distinguish the description of biological experiments and epidemiological observations from definitions and risk projections proposed by international reports and consensus bodies for radioprotection purposes. The next papers deal more specifically with selected aspects of the basic sciences. Dosimetry means quantifying the physical effects of ionizing radiation in human tissue; this is not a straight-forward procedure (I. Cordt). The foundations of general radiation biology are succinctly summarised by C. Michel. An account of our present knowledge and theories of radiation carcinogenesis is provided by W. Burkart. W Lutz compares dose-response models of chemical carcinogenesis with those used in radiation carcinogenesis. During the last decade the epidemiological foundations of radioprotection have changed

  11. Analysis of organophosphate flame retardant diester metabolites in human urine by liquid chromatography electrospray ionisation tandem mass spectrometry.

    PubMed

    Van den Eede, Nele; Neels, Hugo; Jorens, Philippe G; Covaci, Adrian

    2013-08-16

    A new analytical method was developed for the determination of dialkyl and diaryl phosphates (DAPs), which are metabolites of organophosphate triesters (PFRs), in human urine. Target DAPs included dibutyl phosphate (DBP), diphenyl phosphate (DPHP), bis(2-butoxyethyl) phosphate (BBOEP), bis(2-chloroethyl) phosphate (BCEP), bis(1-chloro-2-propyl) phosphate (BCPP), and bis(1,3-dichloro-2-propyl) phosphate (BDCIPP). Sample preparation was based on solid phase extraction using a weak anion exchange sorbent (Oasis WAX). Although several instrumental techniques have been tested, best results were obtained with reversed phase liquid chromatography-negative electrospray ionisation tandem mass spectrometry (LC-ESI-MS/MS) taking the total analysis time into account. Method accuracy at 3ng/mL in pooled urine ranged between 69 and 119% (recovery), while inter-day imprecision (as relative standard deviation) was <31%. The performance of the LC-MS/MS method was compared to a method based on gas chromatography-electron impact tandem mass spectrometry (GC-MS/MS) and a good correlation (Pearson r=0.82, p<0.01) between the results of these two methods was obtained for DPHP. LC-MS/MS analysis was more suitable for DPHP and BBOEP with respective method limits of quantification (mLOQ) of 0.3 and 0.15ng/mL. In contrast, GC-MS/MS had a better sensitivity for BCEP, BCIPP, and BDCIPP, their respective mLOQs being 0.1, 0.06, 0.02ng/mL, compared to 1.2, 3.7, and 0.5ng/mL by LC-MS/MS. A set of urine samples from volunteers was analysed, in which DPHP was the major DAP metabolite. A significant increase of DPHP levels was observed in the group of smokers (geometric mean of 1.55ng/mL) compared to the non-smokers (geometric mean of 0.88ng/mL). Metabolic transformation of triphenyl phosphate to DPHP by metabolic enzymes induced in smokers could be an explanation for this observation. PMID:23849782

  12. Phytosanitation with Ionising Radiation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This book chapter by Neil Heather and Guy Hallman, in “Pest Management and Phytosanitary Trade Barriers,” CABI Press, covers ionizing irradiation phytosanitary treatments. Although irradiation as an idea and research object has as long a phytosanitary history an any other phytosanitary treatment, c...

  13. Identification of N-glycans from Ebola virus glycoproteins by matrix-assisted laser desorption/ionisation time-of-flight and negative ion electrospray tandem mass spectrometry

    PubMed Central

    Ritchie, Gayle; Harvey, David J.; Stroeher, Ute; Feldmann, Friederike; Feldmann, Heinz; Wahl-Jensen, Victoria; Royle, Louise; Dwek, Raymond A.; Rudd, Pauline M.

    2012-01-01

    The larger fragment of the transmembrane glycoprotein (GP1) and the soluble glycoprotein (sGP) of Ebola virus were expressed in human embryonic kidney cells and the secreted products were purified from the supernatant for carbohydrate analysis. The N-glycans were released with PNGase F from within sodium dodecyl sulphate/polyacrylamide gel electrophoresis (SDS-PAGE) gels. Identification of the glycans was made with normal-phase high-performance liquid chromatography (HPLC), matrix-assisted laser desorption/ionisation mass spectrometry, negative ion electrospray ionisation fragmentation mass spectrometry and exoglycosidase digestion. Most glycans were complex bi-, tri-and tetra-antennary compounds with reduced amounts of galactose. No bisected compounds were detected. Triantennary glycans were branched on the 6-antenna; fucose was attached to the core GlcNAc residue. Sialylated glycans were present on sGP but were largely absent from GP1, the larger fragment of the transmembrane glycoprotein. Consistent with this was the generally higher level of processing of carbohydrates found on sGP as evidenced by a higher percentage of galactose and lower levels of high-mannose glycans than were found on GP1. These results confirm and expand previous findings on partial characterisation of the Ebola virus transmembrane glycoprotein. They represent the first detailed data on carbohydrate structures of the Ebola virus sGP. PMID:20131323

  14. Determination of ionisation chamber collection efficiency in a swept electron beam by means of thermoluminescent detectors and the "two-voltage" method.

    PubMed

    Van Dam, J; Rijnders, A; Ang, K K; Mellaerts, M; Grobet, P

    1985-06-01

    Two methods for determining the collection efficiency of a 0.6 cm3 thimble ionisation chamber exposed to the swept electron beam of a linear accelerator Therac 20 Saturne (CGR MeV) have been compared. In one method the chamber signal has been compared to that of simultaneously exposed thermoluminescent LiF dosemeters (TLD), in the other the "two-voltage" method of Boag, adapted for swept beams, has been used. By variation of the electron energy between 20 and 13 MeV, of the focus-skin-distance (FSD) between 200 and 100 cm and of the monitor rate between 400 monitor units (m.u.) and 100 m.u. per minute, different values could be produced for the peak charge density M. The collection efficiency of the chamber, operating at a standard voltage of 250 V, decreases from 0.99 to 0.84 for a charge density increasing from 0.3 X 10(-4) C/m3 to 7.5 X 10(-4) C/m3, respectively. The maximum deviation observed between the TLD and the "two-voltage" method adopted for similar M is never more than 2% and mostly smaller than 1%. It can be concluded that, under the present experimental conditions, the calculated ionisation chamber collection efficiency is confirmed by the experimental method using TL dosimetry. PMID:3925506

  15. Novel characterisation of minor α-linolenic acid isomers in linseed oil by gas chromatography and covalent adduct chemical ionisation tandem mass spectrometry.

    PubMed

    Gómez-Cortés, P; Brenna, J T; Lawrence, P; de la Fuente, M A

    2016-06-01

    Discrimination between polyunsaturated fatty acid isomers with three double bonds is a great challenge, due to structural similarities and similar polarities. In this study, we report the identification of four minor geometrical isomers of α-linolenic acid (ALA) present in linseed oil samples: (9E,12Z,15E)-, (9Z,12Z,15E)-, (9Z,12E,15Z)- and (9E,12Z,15Z)-octadeca-9,12,15-trienoic acids, chromatographically resolved by gas chromatography (GC) using a new and highly polar ionic phase column (SLB-IL111). Gas chromatography-electron ionisation mass spectrometry (GC-EIMS) determined that the four unknown compounds were C18:3 n-3 isomers. The positional 9-12-15 C18:3 configuration was achieved by covalent adduct chemical ionisation tandem mass spectrometry (CACI-MS/MS) while geometrical configuration was established with analytical standards based on relative retention. We hypothesised that these isomers are formed during linseed oil deodorisation and postulate preferred and unfavoured isomerisation pathways of ALA. PMID:26830571

  16. Risk of cancer from occupational exposure to ionising radiation: retrospective cohort study of workers in France, the United Kingdom, and the United States (INWORKS)

    PubMed Central

    Cardis, Elisabeth; Daniels, Robert D; Gillies, Michael; O’Hagan, Jacqueline A; Hamra, Ghassan B; Haylock, Richard; Laurier, Dominique; Leuraud, Klervi; Moissonnier, Monika; Schubauer-Berigan, Mary K; Thierry-Chef, Isabelle; Kesminiene, Ausrele

    2015-01-01

    Study question Is protracted exposure to low doses of ionising radiation associated with an increased risk of solid cancer? Methods In this cohort study, 308 297 workers in the nuclear industry from France, the United Kingdom, and the United States with detailed monitoring data for external exposure to ionising radiation were linked to death registries. Excess relative rate per Gy of radiation dose for mortality from cancer was estimated. Follow-up encompassed 8.2 million person years. Of 66 632 known deaths by the end of follow-up, 17 957 were due to solid cancers. Study answer and limitations Results suggest a linear increase in the rate of cancer with increasing radiation exposure. The average cumulative colon dose estimated among exposed workers was 20.9 mGy (median 4.1 mGy). The estimated rate of mortality from all cancers excluding leukaemia increased with cumulative dose by 48% per Gy (90% confidence interval 20% to 79%), lagged by 10 years. Similar associations were seen for mortality from all solid cancers (47% (18% to 79%)), and within each country. The estimated association over the dose range of 0-100 mGy was similar in magnitude to that obtained over the entire dose range but less precise. Smoking and occupational asbestos exposure are potential confounders; however, exclusion of deaths from lung cancer and pleural cancer did not affect the estimated association. Despite substantial efforts to characterise the performance of the radiation dosimeters used, the possibility of measurement error remains. What this study adds The study provides a direct estimate of the association between protracted low dose exposure to ionising radiation and solid cancer mortality. Although high dose rate exposures are thought to be more dangerous than low dose rate exposures, the risk per unit of radiation dose for cancer among radiation workers was similar to estimates derived from studies of Japanese atomic bomb survivors. Quantifying the cancer risks associated

  17. The Insidious Nature of "Hard-Core" Alternative Conceptions: Implications for the Constructivist Research Programme of Patterns in High School Students' and Pre-Service Teachers' Thinking about Ionisation Energy

    ERIC Educational Resources Information Center

    Taber, Keith S.; Tan, Kim Chwee Daniel

    2011-01-01

    The present study contributes to the constructivist research programme (RP) into learning science by comparing patterns in responses from two groups of learners--senior high school students and pre-service teachers--in the same educational context (Singapore), to a diagnostic instrument relating to the topic of ionisation energies. This topic is…

  18. Secondary ionisations in a wall-less ion-counting nanodosimeter: quantitative analysis and the effect on the comparison of measured and simulated track structure parameters in nanometric volumes

    NASA Astrophysics Data System (ADS)

    Hilgers, Gerhard; Bug, Marion U.; Gargioni, Elisabetta; Rabus, Hans

    2015-10-01

    The object of investigation in nanodosimetry is the physical characteristics of the microscopic structure of ionising particle tracks, i.e. the sequence of the interaction types and interaction sites of a primary particle and all its secondaries, which reflects the stochastic nature of the radiation interaction. In view of the upcoming radiation therapy with protons and carbon ions, the ionisation structure of the ion track is of particular interest. Owing to limitations in current detector technology, the only way to determine the ionisation cluster size distribution in a DNA segment is to simulate the particle track structure in condensed matter. This is done using dedicated computer programs based on Monte Carlo procedures simulating the interaction of the primary ions with the target. Hence, there is a need to benchmark these computer codes using suitable experimental data. Ionisation cluster size distributions produced in the nanodosimeter's sensitive volume by monoenergetic protons and alpha particles (with energies between 0.1 MeV and 20 MeV) were measured at the PTB ion accelerator facilities. C3H8 and N2 were alternately used as the working gas. The measured data were compared with the simulation results obtained with the PTB Monte-Carlo code PTra [B. Grosswendt, Radiat. Environ. Biophys. 41, 103 (2002); M.U. Bug, E. Gargioni, H. Nettelbeck, W.Y. Baek, G. Hilgers, A.B. Rosenfeld, H. Rabus, Phys. Rev. E 88, 043308 (2013)]. Measured and simulated characteristics of the particle track structure are generally in good agreement for protons over the entire energy range investigated. For alpha particles with energies higher than the Bragg peak energy, a good agreement can also be seen, whereas for energies lower than the Bragg peak energy differences of as much as 25% occur. Significant deviations are only observed for large ionisation cluster sizes. These deviations can be explained by a background consisting of secondary ions. These ions are produced in the

  19. Identification of phenolic constituents in red chicory salads (Cichorium intybus) by high-performance liquid chromatography with diode array detection and electrospray ionisation tandem mass spectrometry.

    PubMed

    Carazzone, Chiara; Mascherpa, Dora; Gazzani, Gabriella; Papetti, Adele

    2013-06-01

    Phenolic acids and flavonoids extracted from several types of Cichorium intybus var. silvestre salads ("Chioggia", "Treviso", "Treviso tardivo", and "Verona") were characterised by high-performance liquid chromatography-electrospray ionisation/mass spectrometry. Among the 64 compounds detected, several hydroxycinnamic acid derivatives including 8 mono- and dicaffeoylquinic acids, 3 tartaric acid derivatives, 31 flavonol and 2 flavone glycosides, as well as 10 anthocyanins were characterised based on UV spectra and MS(n) fragmentation patterns. Furthermore, several isomers of caffeic acid derivatives were distinguished for the first time by their specific mass spectral data. This is the first study reporting the glycosylation type and position of mono- and diglycosylated flavonoids in red salads. PMID:23411215

  20. Structural elucidation of monoterpene oxidation products by ion trap fragmentation using on-line atmospheric pressure chemical ionisation mass spectrometry in the negative ion mode.

    PubMed

    Warscheid, B; Hoffmann, T

    2001-01-01

    Based on ion trap mass spectrometry, an on-line method is described which provides valuable information on the molecular composition of structurally complex organic aerosols. The investigated aerosols were generated from the gas-phase ozonolysis of various C(10)H(16)-terpenes (alpha-pinene, beta-pinene, 3-carene, sabinene, limonene), and directly introduced into the ion source of the mass spectrometer. Negative ion chemical ionisation at atmospheric pressure (APCI(-)) enabled the detection of multifunctional carboxylic acid products by combining inherent sensitivity and molecular weight information. Sequential low-energy collision-induced product ion fragmentation experiments (MS(n)) were performed in order to elucidate characteristic decomposition pathways of the compounds. Dicarboxylic acids, oxocarboxylic acids and hydroxyketocarboxylic acid products could be clearly distinguished by multistage on-line MS. Furthermore, sabinonic acid and two C(9)-ether compounds were tentatively identified for the first time by applying on-line APCI(-)-MS(n). PMID:11746892

  1. Rapid identification of vinca alkaloids by direct-injection electrospray ionisation tandem mass spectrometry and confirmation by high-performance liquid chromatography-mass spectrometry.

    PubMed

    Zhou, Hui; Tai, Yuanpo; Sun, Cuirong; Pan, Yuanjiang

    2005-01-01

    A simple and rapid method for the identification of Vinca alkaloids from a crude extract of Catharanthus roseus G. Don (Apocynaceae) by direct-injection electrospray ionisation (ESI) and tandem mass spectrometry (MS/MS) has been developed. The alkaloids vindoline, vindolidine, vincristine and vinblastine were evaluated in a commercial extract of C. roseus using this method. Catharanthine and its isomers 19S-vindolinine and vindolinine were detected in the commercial product by direct injection ESI/MS/MS and confirmed by preparation and by HPLC-ESI/MS. For the characterisation of different fragment fingerprints, ESI/MS/MS is a sensitive, rapid and convenient technique by which to identify some constituents in complex and mixed plant extracts. PMID:16223089

  2. SPECIAL ISSUE DEVOTED TO THE 25th ANNIVERSARY OF THE A.M. PROKHOROV GENERAL PHYSICS INSTITUTE: Femtosecond laser optical gas breakdown microplasma: the ionisation and postionisation dynamics

    NASA Astrophysics Data System (ADS)

    Bukin, V. V.; Garnov, S. V.; Malyutin, A. A.; Strelkov, V. V.

    2007-10-01

    The formation and evolution dynamics of the laser plasma produced in the microvolumes of gases (air, nitrogen, argon, and helium) upon their multiple ionisation by high-intensity (4×1016 W cm-2) tightly focused (to a region 1.7 μm in diameter) 400-nm, 100-fs second-harmonic pulses from a Ti:sapphire laser is studied. The spatiotemporal distribution profiles of the refractive index and electron microplasma density were recorded by ultrahigh-speed interferometry. The postionisation of a femtosecond laser plasma, i.e. the growth of the electron density known after the end of the exciting laser pulse, is detected for the first time. A theoretical model is proposed, which describes the mechanism of plasma postionisation by hot photoelectrons. The results of electron density calculations are in good agreement with experimental data.

  3. Analysis of trace amounts of carbon dioxide, oxygen and carbon monoxide in nitrogen using dual capillary columns and a pulsed discharge helium ionisation detector.

    PubMed

    Janse van Rensburg, M; Botha, A; Rohwer, E

    2007-10-01

    Gas mixtures of trace amounts of carbon dioxide (CO(2)), dioxygen (O(2)), and carbon monoxide (CO) in dinitrogen (N(2)) were separated and quantified using parallel dual capillary columns and pulsed discharge helium ionisation detection (PDHID). The detection limits (9 x 10(-9) mol mol(-1) for CO(2), 7 x 10(-9) mol mol(-1) for O(2) and 37 x 10(-9) mol mol(-1) for CO) were lower than those reported previously for similar methods. Uncertainties were calculated and results were validated by comparison of the CO and CO(2) results with those obtained using conventional methods. The method was also used to analyse nitrogen, carbon dioxide and carbon monoxide in oxygen. PMID:17765907

  4. Ionisation potential theorem in the presence of the electric field: Assessment of range-separated functional in the reproduction of orbital and excitation energies

    NASA Astrophysics Data System (ADS)

    Borpuzari, Manash Protim; Boruah, Abhijit; Kar, Rahul

    2016-04-01

    Recently, the range-separated density functionals have been reported to reproduce gas phase orbital and excitation energies with good accuracy. In this article, we have revisited the ionisation potential theorem in the presence of external electric field. Numerical results on six linear molecules are presented and the performance of the range-separated density functionals in reproducing highest occupied molecular orbital (HOMO) energies, LUMO energies, HOMO-LUMO gaps in the presence of the external electric field is assessed. In addition, valence and Rydberg excitation energies in the presence of the external electric field are presented. It is found that the range-separated density functionals reproduce orbital and excitation energies accurately in the presence of the electric field. Moreover, we have performed fractional occupation calculation using cubic spline equation and tried to explain the performance of the functional.

  5. High-performance liquid chromatographic separation of natural and synthetic desulphoglucosinolates and their chemical validation by UV, NMR and chemical ionisation-MS methods.

    PubMed

    Kiddle, G; Bennett, R N; Botting, N P; Davidson, N E; Robertson, A A; Wallsgrove, R M

    2001-01-01

    Methods are described for the optimised extraction, desulphation and HPLC separation of desulphoglucosinolates. These methods provide rapid separation, identification and quantitative measurements of glucosinolates extracted from Brassica napus L and related crops, of unusual glucosinolates found in crucifer weed species, and also of synthetic alkylglucosinolates. The desulphoglucosinolates used in these studies were either chemically synthesised (at least one example from each major structural class), or purified from various plant sources. Validation of the identities of the desulphoglucosinolates was by comparison of retention times with standards, and by UV, 1H- and 13C-NMR and chemical ionisation MS analysis. A list of useful species, and the specific tissues, from which high concentrations of standards can be extracted is included. PMID:11705329

  6. Characterisation of weathered hydrocarbon wastes at contaminated sites by GC-simulated distillation and nitrous oxide chemical ionisation GC-MS, with implications for bioremediation.

    PubMed

    Pollard, Simon J T; Hrudey, Steve E; Rawluk, Marv; Fuhr, Bryan J

    2004-08-01

    An extended analytical characterisation of weathered hydrocarbons isolated from historically contaminated sites in Alberta is presented. The characterisation of soil extracts, chromatographically separated into component classes, by GC-simulated distillation and nitrous oxide (N2O) chemical ionisation (CI) GC-MS provides new insights into the composition of the residual oil at these sites, the principal partition medium for risk critical components. The combined polar and asphaltene content of representative soil extracts ranged from 40% w/w to 70% w/w of the oils encountered. An abundance of C14-C22 2-4 ring alicyclics, alkylbenzenes and benzocycloparaffins is prevalent within the saturate fractions of site soils. Implications for the partitioning of risk critical compounds at sites with weathered hydrocarbons and the practical application of bioremediation technologies are discussed. PMID:15292955

  7. 2B or not 2B, that is the question: further investigations into the use of pencil as a matrix for matrix-assisted laser desorption/ionisation.

    PubMed

    Langley, G John; Herniman, Julie M; Townell, Marc S

    2007-01-01

    The effective use of pencil as a matrix for matrix-assisted laser desorption/ionisation (MALDI) for the study of actinides has previously been demonstrated (Black et al., Rapid Commun. Mass Spectrom. 2006; 20: 1053). Here, the scope of the types of molecules amenable to analysis by this method has been extended, establishing that approximately 90% of a library containing 50 diverse small molecules can be successfully analysed by this technique. Further, the role played by the bulk materials present in the different pencil leads has been investigated and a simple one-step deposition of matrix and calibration materials has been achieved through the fabrication of different calibration pencils (Cali-Pens). PMID:17171774

  8. Ionising Radiation Immediately Impairs Synaptic Plasticity-Associated Cytoskeletal Signalling Pathways in HT22 Cells and in Mouse Brain: An In Vitro/In Vivo Comparison Study

    PubMed Central

    Kempf, Stefan J.; Buratovic, Sonja; von Toerne, Christine; Moertl, Simone; Stenerlöw, Bo; Hauck, Stefanie M.; Atkinson, Michael J.; Eriksson, Per; Tapio, Soile

    2014-01-01

    Patients suffering from brain malignancies are treated with high-dose ionising radiation. However, this may lead to severe learning and memory impairment. Preventive treatments to minimise these side effects have not been possible due to the lack of knowledge of the involved signalling pathways and molecular targets. Mouse hippocampal neuronal HT22 cells were irradiated with acute gamma doses of 0.5 Gy, 1.0 Gy and 4.0 Gy. Changes in the cellular proteome were investigated by isotope-coded protein label technology and tandem mass spectrometry after 4 and 24 hours. To compare the findings with the in vivo response, male NMRI mice were irradiated on postnatal day 10 with a gamma dose of 1.0 Gy, followed by evaluation of the cellular proteome of hippocampus and cortex 24 hours post-irradiation. Analysis of the in vitro proteome showed that signalling pathways related to synaptic actin-remodelling were significantly affected at 1.0 Gy and 4.0 Gy but not at 0.5 Gy after 4 and 24 hours. We observed radiation-induced reduction of the miR-132 and Rac1 levels; miR-132 is known to regulate Rac1 activity by blocking the GTPase-activating protein p250GAP. In the irradiated hippocampus and cortex we observed alterations in the signalling pathways similar to those in vitro. The decreased expression of miR-132 and Rac1 was associated with an increase in hippocampal cofilin and phospho-cofilin. The Rac1-Cofilin pathway is involved in the modulation of synaptic actin filament formation that is necessary for correct spine and synapse morphology to enable processes of learning and memory. We suggest that acute radiation exposure leads to rapid dendritic spine and synapse morphology alterations via aberrant cytoskeletal signalling and processing and that this is associated with the immediate neurocognitive side effects observed in patients treated with ionising radiation. PMID:25329592

  9. Analysis of peptides and protein digests by reversed phase high performance liquid chromatography-electrospray ionisation mass spectrometry using neutral pH elution conditions.

    PubMed

    Yang, Yuanzhong; Boysen, Reinhard I; Chowdhury, Jamil; Alam, Asif; Hearn, Milton T W

    2015-05-01

    In this study, the advantages of carrying out the analysis of peptides and tryptic digests of proteins under gradient elution conditions at pH 6.5 by reversed-phase liquid chromatography (RP-HPLC) and in-line electrospray ionisation mass spectrometry (ESI-MS) are documented. For these RP separations, a double endcapped, bidentate anchored n-octadecyl wide pore silica adsorbent was employed in a capillary column format. Compared to the corresponding analysis of the same peptides and protein tryptic digests using low pH elution conditions for their RP-HPLC separation, this alternative approach provides improved selectivity and more efficient separation of these analytes, thus allowing a more sensitive identification of proteins at different abundance levels, i.e. more tryptic peptides from the same protein could be confidently identified, enabling higher sequence coverage of the protein to be obtained. This approach was further evaluated with very complex tryptic digests derived from a human plasma protein sample using an online two-dimensional (2D) strong cation-exchange (SCX)-RP-HPLC-ESI-MS/MS system. Again, at pH 6.5, with mobile phases of different compositions, improved chromatographic selectivities were obtained, concomitant with more sensitive on-line electrospray ionisation tandem mass spectrometric (ESI-MS/MS) analysis. As a consequence, more plasma proteins could be confidently identified, highlighting the potential of these RP-HPLC methods with elution at pH 6.5 to extend further the scope of proteomic investigations. PMID:25892073

  10. Characterisation of legumes by enzymatic hydrolysis, microdialysis sampling, and micro-high-performance anion-exchange chromatography with electrospray ionisation mass spectrometry.

    PubMed

    Okatch, Harriet; Torto, Nelson; Armateifio, Joan

    2003-04-11

    An assay based on enzymatic hydrolysisand microdialysis sampling, micro-high-performance anion-exchange chromatography (micro-HPAEC) with electrospray ionisation mass spectrometry (ESI-MS) for the characterisation of legumes is presented. Characterisation of two bean varieties; Phaseolus mungo and P. acutifilous was based upon enzymatic hydrolysis using an endo-beta-mannanase from Aspergillus niger with subsequent analysis of the hydrolysates with HPAEC-MS. The hydrolysates were detected in the positive ionisation mode after desalting the chromatographic effluent, employing a cation-exchange membrane desalting device with water as the regenerating liquid. Mass chromatograms, acquiredafter hydrolysis of both bean samples for 12 h, showed two different profiles of hydrolysates. The P. mungo bean hydrolysate showed the presence of saccharides with a degree of polymerisation (DP) in the range of 2-6, whereas that of P. acutifilous showed only DPs of 2-5. Both bean samples had one type of DP 2, but showed different types of DPs 3, 4 and 5. Only the P. mungo sample showed the presence of DP 6. The most abundant fraction for P. mungo was DP 4, whereas that for P. acutifilous was DP 5. Tandem MS of the hydrolysates showed that the DP 2 hydrolysates observed for the samples were of the same type, having a 1,6 linkage. Also tandem MS data for DPs 3, 4, and 5 showed that similar hydrolysates were present within the same sample as well as among the two samples. The data also showed the existence of 1,6 linkages for DP 3, 4, and 5 hydrolysates. The single enzymatic hydrolysis in combination with microdialysis and HPAEC with ESI-MS proved to be sufficient and reproducible for profiling and showing the difference between the two bean samples. PMID:12735463

  11. Measurement of small ion beams by thermal ionisation mass spectrometry using new 10(13) Ohm resistors.

    PubMed

    Koornneef, J M; Bouman, C; Schwieters, J B; Davies, G R

    2014-03-28

    We tested 5 newly manufactured - prototype - 10(13)Ohm resistors in the feedback loop of Faraday cup amplifiers to measure small ion beams by Thermal Ionisation Mass Spectrometry (TIMS). The high Ohmic resistors installed in the TRITON Plus at the VU University Amsterdam theoretically have 10 times lower noise levels relative to the default 10(11)Ohm resistors. To investigate the precision and accuracy of analyses using these new amplifiers we measured Sr and Nd isotopes of reference standards at a range of ion currents (3.2×10(-16) to 1×10(-12) A, corresponding to intensities of 32 μV to 100 mV on a default 10(11)Ohm amplifier) and on small amounts of material (100 and 10 pg). Internal precision and external reproducibility for Sr and Nd isotope ratios are both better when collected on 10(13) compared 10(12)Ohm resistors and to the default 10(11)Ohm resistors. At an (87)Sr ion current of 3×10(-14) A (3 mV on a 10(11)Ohm amplifier) the internal precision (2 SE) of (87)Sr/(86)Sr is 5 times better for 10(13)Ohm resistors compared to 10(11)Ohm resistors. The external reproducibility (2 SD) at this beam intensity is 9 times better. Multiple 100 and 10 pg Sr standards, ran to exhaustion, yielded low (87)Sr/(86)Sr compared to the long term average (e.g. 10 pg average=0.710083±164 (n=11) instead of 0.710244±12, n=73). The average off-set for 10 pg standards can be explained by a loading blank contribution of 1.3 pg. In contrast, Nd data on 100 pg and 10 pg samples are accurate suggesting that Nd loading blanks do not compromise the data. The external reproducibility of (143)Nd/(144)Nd on 100 pg samples is 125 ppm and 3.3‰ on 10 pg samples (2 RSD=relative standard deviation, n=10). Thus, variability in Nd and Sr isotope ratios in the 4th decimal place, e.g. (143)Nd/(144)Nd 0.5110-0.5119 or (87)Sr/(86)Sr 0.7100-0.7109, can be resolved in 10 to 100 pg samples provided that the procedural blanks and chemical separation are optimal. For measurements in the beam

  12. A miniaturised laser ablation/ionisation analyser for investigation of elemental/isotopic composition with the sub-ppm detection sensitivity

    NASA Astrophysics Data System (ADS)

    Tulej, M.; Riedo, A.; Meyer, S.; Iakovleva, M.; Neuland, M.; Wurz, P.

    2012-04-01

    Detailed knowledge of the elemental and isotopic composition of solar system objects imposes critical constraints on models describing the origin of our solar system and can provide insight to chemical and physical processes taking place during the planetary evolution. So far, the investigation of chemical composition of planetary surfaces could be conducted almost exclusively by remotely controlled spectroscopic instruments from orbiting spacecraft, landers or rovers. With some exceptions, the sensitivity of these techniques is, however, limited and often only abundant elements can be investigated. Nevertheless, the spectroscopic techniques proved to be successful for global chemical mapping of entire planetary objects such as the Moon, Mars and asteroids. A combined afford of the measurements from orbit, landers and rovers can also yield the determination of local mineralogy. New instruments including Laser Induced Breakdown Spectroscopy (LIBS) and Laser Ablation/Ionisation Mass Spectrometer (LIMS), have been recently included for several landed missions. LIBS is thought to improve flexibility of the investigations and offers a well localised chemical probing from distances up to 10-13 m. Since LIMS is a mass spectrometric technique it allows for very sensitive measurements of elements and isotopes. We will demonstrate the results of the current performance tests obtained by application of a miniaturised laser ablation/ionisation mass spectrometer, a LIMS instrument, developed in Bern for the chemical analysis of solids. So far, the only LIMS instrument on a spacecraft is the LAZMA instrument. This spectrometer was a part of the payload for PHOBOS-GRUNT mission and is also currently selected for LUNA-RESURCE and LUNA-GLOB missions to the lunar south poles (Managadze et al., 2011). Our LIMS instrument has the dimensions of 120 x Ø60 mm and with a weight of about 1.5 kg (all electronics included), it is the lightest mass analyser designed for in situ chemical

  13. A new approach for plasma (xeno)metabolomics based on solid-phase extraction and nanoflow liquid chromatography-nanoelectrospray ionisation mass spectrometry.

    PubMed

    David, Arthur; Abdul-Sada, Alaa; Lange, Anke; Tyler, Charles R; Hill, Elizabeth M

    2014-10-24

    Current metabolite profiling methods based on liquid chromatography-mass spectrometry (LC-MS) platforms do not detect many of the components present at trace concentrations in extracts of plasma due to their low ionisation efficiency or to interference from highly abundant compounds. Nanoflow LC-nanospray MS platforms, which are commonly used in proteomics, could overcome these limitations and significantly increase analytical sensitivity and coverage of the plasma (xeno)metabolome (i.e., metabolites and xenobiotics), but require small injection volumes (<0.5μL). In this study, we developed sample preparation methods to remove ion suppressive phospholipids and concentrate remaining components of the plasma (xeno)metabolome in order to analyse sub-microliter volumes of plasma extracts for nanoflow ultra-high-performance liquid chromatography-nanoelectrospray ionisation-time-of-flight mass spectrometry (nUHPLC-nESI-TOFMS). These methods use phospholipid filtration plates in combination with polymeric or mixed mode exchange solid-phase extraction (SPE). The phospholipid filtration plates removed >94% of the predominant phospholipid/lysophospholipid species from plasma, whilst absolute recoveries of 63 selected (xeno)metabolites from spiked plasma were generally between 60 and 104%. After a further SPE step, recoveries of test compounds were between 50 and 81%. Studies revealed that both the sample preparation methodology and nUHPLC-nESI-TOFMS analyses gave acceptable repeatability. A qualitative comparison of SPE methods revealed that sample concentration by either polymer or mixed mode ion-exchange SPE gave comprehensive metabolite coverage of plasma extracts, but the use of cation exchange SPE significantly increased detection of many cationic compounds in the sample extracts. Method detection limits for steroid, eicosanoid and bile metabolites were <1.0ng/mL plasma and for pharmaceutical contaminants were between 0.01 and 30ng/mL plasma. Comparison of the

  14. Combined effect of solvent content, temperature and pH on the chromatographic behaviour of ionisable compounds. III: Considerations about robustness.

    PubMed

    Pous-Torres, S; Torres-Lapasió, J R; Baeza-Baeza, J J; García-Alvarez-Coque, M C

    2009-12-18

    We previously reported a model able to predict the retention time of ionisable compounds as a function of the solvent content, temperature and pH [J. Chromatogr. A 1163 (2007) 49]. The model was applied further, developing an optimisation of the resolution based on the peak purity concept [J. Chromatogr. A 1193 (2008) 117]. However, we left aside an important issue: we did not consider incidental overlaps caused by shifts in the predicted peak positions, owing either to uncertainties in the source data, modelling errors, or the practical implementation in the chromatograph of the optimal mobile phase (or any other). These shifts can ruin the predicted separation, since they can easily amount several peak-width units at pH values close to the logarithm of the solutes' acid-base constants. A probabilistic optimisation is proposed here, which is able to evaluate the uncertainties associated with the model and the consequences when the optimal mobile phase is implemented in the chromatograph. This approach assumes peak fluctuations in replicated assays obtained through Monte Carlo simulations, which gives rise to a distribution of elementary peak purities. The results yielded by the conventional (i.e. non-robust), derivative-penalised, and probabilistic optimisations were compared, checking the predicted and experimental chromatograms at several critical experimental conditions. Among the three approaches, only the probabilistic one was able to appraise properly the practical difficulties of the separation problem. PMID:19909960

  15. Structural characterisation of tyrosine-nitrated peptides by ultraviolet and infrared matrix-assisted laser desorption/ionisation Fourier transform ion cyclotron resonance mass spectrometry.

    PubMed

    Petre, Brínduşa-Alina; Youhnovski, Nikolay; Lukkari, Juho; Weber, Reinhold; Przybylski, Michael

    2005-01-01

    Nitration of tyrosine residues in proteins may occur in cells upon oxidative stress and inflammation processes mediated through generation of reactive nitroxyl from peroxynitrite. Tyrosine nitration from oxidative pathways may generate cytotoxic species that cause protein dysfunction and pathogenesis. A number of protein nitrations in vivo have been reported and some specific Tyrosine nitration sites have been recently identified using mass spectrometric methods. High-resolution Fourier transform ion cyclotron resonance mass spectrometry (MALDI) FT-ICR-MS) is shown here to be a highly efficient method in the determination of protein nitrations. Following the identification of nitration of the catalytic site Tyr-430 residue of bovine prostacyclin synthase, we synthesised several model peptides containing both unmodified tyrosine and 3-nitro-tyrosine residues, using solid-phase peptide synthesis (SPPS). The structures of the nitrotyrosine peptides were characterised both by ESI- and by matrix-assisted laser desorption/ionisation (MALDI)-FT-ICR-MS, using a standard ultraviolet (UV) nitrogen nitrogen laser and a 2.97 microm Nd-YAG infrared laser. Using UV-MALDI-MS, 3-nitrotyrosyl-peptides were found to undergo extensive photochemical fragmentation at the nitrophenyl group, which may hamper or prevent the unequivocal identification of Tyr-nitrations in cellular proteins. In contrast, infrared-MALDI-FT-ICR-MS did not produce fragmentation of molecular ions of Tyr-nitrated peptides. PMID:16322657

  16. Fractionation and analysis of lipopolysaccharide-derived oligosaccharides by zwitterionic-type hydrophilic interaction liquid chromatography coupled with electrospray ionisation mass spectrometry.

    PubMed

    Man-Kupisinska, Aleksandra; Bobko, Ewelina; Gozdziewicz, Tomasz K; Maciejewska, Anna; Jachymek, Wojciech; Lugowski, Czeslaw; Lukasiewicz, Jolanta

    2016-06-01

    Lipopolysaccharide (LPS, endotoxin) is a main surface antigen and virulence factor of Gram-negative bacteria. Regardless of the source of LPS, this molecule, isolated from the smooth forms of bacteria, is characterised by a general structural layout encompassing three regions: (i) an O-specific polysaccharide (O-PS) - a polymer of repeating oligosaccharide units, (ii) core oligosaccharide (OS), and (iii) the lipid A anchoring LPS in the outer membrane of the cell envelope of Gram-negative bacteria. Structural analysis usually requires degradation of LPS and further efficient separation of various poly- and oligosaccharide glycoforms. The hydrophilic interaction liquid chromatography (HILIC) was shown as an efficient technique for separation of labelled or native neutral and acidic glycans, glycopeptides, sialylated glycans, glycosylated and nonglycosylated peptides. Herein we adopted ZIC(®) (zwitterionic stationary phase covalently attached to porous silica)-HILIC technology in combination with electrospray ionisation mass spectrometry to separate different LPS-derived oligosaccharides. As a result three effective procedures have been developed: (i) to separate different core oligosaccharides of Escherichia coli R1 LOS, (ii) to separate RU-[Hep]-Kdo oligosaccharides from core OS glycoforms of Hafnia alvei PCM 1200 LPS, and (iii) to separate Hep and Kdo-containing mono, di-, tri- and tetrasaccharides of H. alvei PCM 1200 LPS. Moreover, some of developed analytical procedures were scaled to semi-preparative protocols and used to obtain highly-purified fractions of the interest in larger quantities required for future evaluation, analysis, and biological applications. PMID:27085741

  17. Simultaneous determination of 16 brominated flame retardants in food and feed of animal origin by fast gas chromatography coupled to tandem mass spectrometry using atmospheric pressure chemical ionisation.

    PubMed

    Bichon, E; Guiffard, I; Vénisseau, A; Lesquin, E; Vaccher, V; Brosseaud, A; Marchand, P; Le Bizec, B

    2016-08-12

    A gas chromatography tandem mass spectrometry method using atmospheric pressure chemical ionisation was developed for the monitoring of 16 brominated flame retardants (7 usually monitored polybromodiphenylethers (PBDEs) and BDE #209 and 8 additional emerging and novel BFRs) in food and feed of animal origin. The developed analytical method has decreased the run time by three compared to conventional strategies, using a 2.5m column length (5% phenyl stationary phase, 0.1mm i.d., 0.1μmf.t.), a pulsed split injection (1:5) with carrier gas helium flow rate at 0.48mLmin(-1) in one run of 20 min. For most BFRs, analytical data were compared with the current analytical strategy relying on GC/EI/HRMS (double sector, R=10000 at 10% valley). Performances in terms of sensitivity were found to meet the Commission recommendation (118/2014/EC) for nBFRs. GC/APCI/MS/MS represents a promising alternative for multi-BFRs analysis in complex matrices, in that it allows the monitoring of a wider list of contaminants in a single injection and a shorter run time. PMID:27425757

  18. Sensitive monitoring of monoterpene metabolites in human urine using two-step derivatisation and positive chemical ionisation-tandem mass spectrometry.

    PubMed

    Schmidt, Lukas; Belov, Vladimir N; Göen, Thomas

    2013-09-01

    A gas chromatographic-positive chemical ionisation-tandem mass spectrometric (GC-PCI-MS/MS) method for the simultaneous determination of 10 oxidative metabolites of the monoterpenoid hydrocarbons α-pinene, (R)-limonene, and Δ(3)-carene ((+)-3-carene) in human urine was developed and tested for the monoterpene biomonitoring of the general population (n=36). The method involves enzymatic cleavage of the glucuronides followed by solid-supported liquid-liquid extraction and derivatisation using a two-step reaction with N,O-bis(trimethylsilyl)-trifluoroacetamide and N-(trimethylsilyl)imidazole. The method proved to be both sensitive and reliable with detection limits ranging from 0.1 to 0.3 μg L(-1). In contrast to the frequent and distinct quantities of (1S,2S,4R)-limonene-1,2-diol, the (1R,2R,4R)-stereoisomer could not be detected. The expected metabolite of (+)-3-carene, 3-caren-10-ol was not detected in any of the samples. All other metabolites were detected in almost all urine samples. The procedure enables for the first time the analysis of trace levels of a broad spectrum of mono- and bicyclic monoterpenoid metabolites (alcohols, diols, and carboxylic acids) in human urine. This analytical procedure is a powerful tool for population studies as well as for the discovery of human metabolism and toxicokinetics of monoterpenes. PMID:23953203

  19. Analysis of the bovine plasma proteome by matrix-assisted laser desorption/ionisation time-of-flight tandem mass spectrometry.

    PubMed

    Henning, Ann-Kristin; Groschup, Martin H; Mettenleiter, Thomas C; Karger, Axel

    2014-01-01

    In this study, the bovine plasma proteome was analysed using a three step protocol: (1) plasma was treated with a combinatorial peptide ligand library (CPLL) to assimilate the differences in concentrations of different proteins in raw plasma; (2) CPLL-treated material was fractionated by three standard electrophoretic separation techniques, and (3) samples were analysed by nano-liquid chromatography (nLC) matrix-assisted laser desorption/ionisation (MALDI) time-of-flight tandem (TOF/TOF) mass spectrometry. The efficiencies of three fractionation protocols for plasma proteome analysis were compared. After size fractionation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), resolution of proteins was better and yields of identified proteins were higher than after charge-based fractionation by preparative gel-free isoelectric focussing. For proteins with isoelectric points >6 and molecular weights ⩾ 63 kDa, the best results were obtained with a 'shotgun' approach, in which the CPLL-treated plasma was digested and the peptides, rather than the proteins, were fractionated by gel-free isoelectric focussing. However, the three fractionation techniques were largely complementary, since only about one-third of the proteome was identified by each approach. PMID:24268478

  20. The analysis of beta-agonists by packed-column supercritical fluid chromatography with ultra-violet and atmospheric pressure chemical ionisation mass spectrometric detection.

    PubMed

    Jones, D C; Dost, K; Davidson, G; George, M W

    1999-06-01

    Packed-column supercritical fluid chromatography (pSFC) using ultra-violet (UV) and atmospheric pressure chemical ionisation (APCI) mass spectrometry (MS) provides a versatile method for the identification and quantification of beta-agonists. We have achieved good separation of clenbuterol, salbutamol, terbutaline and fenoterol with good resolution and reasonable retention times using a high concentration of methanol modifier in the supercritical CO2, together with small amounts of both acidic (trifluoroacetic acid, TFAA) and basic (triethylamine, TEA, or diethylamine, DEA) additives. APCI-MS gave unambiguous identification of the 4 analytes, and increasing cone voltage provided informative fragmentation patterns. The pSFC-MS technique was shown to be linear (R2 > or = 0.996) over the concentration range 1-50 micrograms ml-1. Single ion monitoring (SIM) gave detection limits (on-column) of 2.5 ng (clenbuterol), 0.83 ng (terbutaline), 7.6 ng (salbutamol) and 2.7 ng (fenoterol). The pSFC-MS system was shown to be reproducible within a day, between days, and between restrictors. Analysis of milk samples 'spiked' with beta-agonists showed that the matrix caused no interference, with detection limits of approximately 500 micrograms l-1 of beta-agonists. More dilute solutions could be analysed by pre-concentration before the SFC stage. PMID:10736867

  1. Improvement in the Iatroscan thin-layer chromatographic-flame ionisation detection analysis of marine lipids. Separation and quantitation of monoacylglycerols and diacylglycerols in standards and natural samples.

    PubMed

    Striby, L; Lafont, R; Goutx, M

    1999-07-23

    Mono- and diacylglycerols are important intermediates in glycerolipid biodegradation and intracellular signalling pathways. A method for mass determination of these lipid classes in marine particles was developed using the Iatroscan, which combines thin layer chromatography (TLC) and flame ionisation detection (FID) techniques. We improved existing protocols by adding two elution steps: hexane-diethyl-ether-formic acid (70:30:0.2, v/v/v) after triacylglycerol and free fatty acid scan, and acetone 100% followed by chloroform-acetone-formic acid (99:1:0.2, v/v/v) after 1,2 diacylglycerols. Diacylglycerol isomers 1,2 and 1,3 were separated from each other, as well as from free sterols in standards and marine lipids from sediment trap particles. Monoacylglycerols were separated from pigments and galactosyl-lipids in the same trap samples and in a rich pigment phytoplankton extract of Dunaliella viridis. Quantitation of each class in samples was performed after calibration with 0.5 to 2 micrograms of standards. As many as 17 lipid classes can be identified and quantified in samples using this proposed six-step development. PMID:10457435

  2. Real-time analysis of organic compounds in ship engine aerosol emissions using resonance-enhanced multiphoton ionisation and proton transfer mass spectrometry.

    PubMed

    Radischat, Christian; Sippula, Olli; Stengel, Benjamin; Klingbeil, Sophie; Sklorz, Martin; Rabe, Rom; Streibel, Thorsten; Harndorf, Horst; Zimmermann, Ralf

    2015-08-01

    Organic combustion aerosols from a marine medium-speed diesel engine, capable to run on distillate (diesel fuel) and residual fuels (heavy fuel oil), were investigated under various operating conditions and engine parameters. The online chemical characterisation of the organic components was conducted using a resonance-enhanced multiphoton ionisation time-of-flight mass spectrometer (REMPI TOF MS) and a proton transfer reaction-quadrupole mass spectrometer (PTR-QMS). Oxygenated species, alkenes and aromatic hydrocarbons were characterised. Especially the aromatic hydrocarbons and their alkylated derivatives were very prominent in the exhaust of both fuels. Emission factors of known health-hazardous compounds (e.g. mono- and poly-aromatic hydrocarbons) were calculated and found in higher amounts for heavy fuel oil (HFO) at typical engine loadings. Lower engine loads lead in general to increasing emissions for both fuels for almost every compound, e.g. naphthalene emissions varied for diesel fuel exhaust between 0.7 mg/kWh (75 % engine load, late start of injection (SOI)) and 11.8 mg/kWh (10 % engine load, late SOI) and for HFO exhaust between 3.3 and 60.5 mg/kWh, respectively. Both used mass spectrometric techniques showed that they are particularly suitable methods for online monitoring of combustion compounds and very helpful for the characterisation of health-relevant substances. Graphical abstract Three-dimensional REMPI data of organic species in diesel fuel and heavy fuel oil exhaust. PMID:25600686

  3. Rapid monitoring of carvacrol in plants and herbal medicines using matrix solid-phase dispersion and gas chromatography flame ionisation detector.

    PubMed

    Rashidipour, Marzieh; Heydari, Rouhollah; Feizbakhsh, Alireza; Hashemi, Payman

    2015-01-01

    Matrix solid-phase dispersion (MSPD) method coupled with gas chromatography flame ionisation detector as a quick and easy extraction technique has been developed to extract carvacrol from plants and herbal medicines. Influence of important parameters on the MSPD method efficiency, such as the sorbent material, the ratio of sample to sorbent material, elution solvent and volume of the elution solvent has been evaluated and optimised. Carvacrol was successfully extracted by diatomaceous earth as sorbent with 350 μL of dichloromethane as elution solvent. The calibration curve showed good linearity (r(2) = 0.9965) and precision (RSD < 8.16%) in the concentration range of 0.5-100 μg mL(-1) for carvacrol. The limit of detection and limit of quantification were 0.1 and 0.5 μg mL(-1), respectively. The recoveries were in the range of 74.4-80.5% with relative standard deviation (RSD) values ranging from 8.4% to 9.8%. The reported MSPD extraction method revealed to be simpler and faster than conventional methods used to quantify carvacrol from plants and herbal medicines. PMID:25421885

  4. Elucidating the structure of carbon nanoparticles by ultra-performance liquid chromatography coupled with electrospray ionisation quadrupole time-of-flight tandem mass spectrometry.

    PubMed

    Hu, Qin; Meng, Xiangpeng; Choi, Martin M F; Gong, Xiaojuan; Chan, Wan

    2016-03-10

    A fast and accurate ultra-performance liquid chromatography coupled with electrospray ionisation quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS/MS) method was developed for the separation and structural elucidation of fluorescent carbon nanoparticles (CNP). The CNP was synthesised from microwave-assisted pyrolysis of citric acid (CA) and 1,2-ethylenediamine (EDA). By using UPLC separation, the CNP product was well separated into ten fractions within 4.0 min. Based on high-accuracy MS and MS/MS analyses, the CNP species were revealed to display six kinds of chemical formulas, including (C10H20N4O5)n, (C8H12N2O5)n, (C16H22N4O9)n, (C6H8O7)n, (C14H18N2O11)n, and (C14H16N2O10)n. In particular, our study revealed for the first time that the CNP species exist as supramolecular clusters with their individual monomers units linked together through non-covalent bonding forces. These findings clearly indicated the usefulness of UPLC-ESI-Q-TOF-MS/MS in identifying the chemical composition of CNP product. It is anticipated that our proposed methodology can be applied to study the structure-property relationships of CNP, facilitating in the production of CNP with desirable spectral features. PMID:26893091

  5. A novel matrix-assisted laser desorption/ionisation mass spectrometry imaging based methodology for the identification of sexual assault suspects.

    PubMed

    Bradshaw, Robert; Wolstenholme, Rosalind; Blackledge, Robert D; Clench, Malcolm R; Ferguson, Leesa S; Francese, Simona

    2011-02-15

    An increase in the use of condoms by sexual offenders has been observed. This is likely to be due both to the risk of sexually transmitted diseases and to prevent the transfer of DNA evidence. In this scenario the detection of condom lubricants at a crime scene could aid in proving corpus delicti. Here we show a novel application of Matrix-Assisted Laser Desorption/Ionisation Mass Spectrometry Imaging (MALDI MSI) for mapping the fingermark ridge pattern simultaneously to the detection of the condom lubricant within the fingermark itself. Two condom brands have been investigated to prove the concept. Condoms were handled producing lubricant-contaminated fingermarks. Images of the ridge pattern were obtained simultaneously to the detection of two lubricants, even several weeks after the fingermark deposition. The results therefore show the potential of MALDI MSI to link the suspect (identification through fingermark ridge pattern) to the crime (detection of condom lubricant) in one analysis. This would enable forensic scientists to provide evidence with stronger support in alleged cases of sexual assault. PMID:21213360

  6. How do monomeric components of a polymer gel dosimeter respond to ionising radiation: A steady-state radiolysis towards preparation of a 3D polymer gel dosimeter

    NASA Astrophysics Data System (ADS)

    Kozicki, Marek

    2011-12-01

    Ionising radiation-induced reactions of aqueous single monomer solutions and mixtures of poly(ethylene glycol) diacrylate (PEGDA) and N, N'-methylenebisacrylamide (Bis) in a steady-state condition are presented below and above gelation doses in order to highlight reactions in irradiated 3D polymer gel dosimeters, which are assigned for radiotherapy dosimetry. Both monomers are shown to undergo radical polymerisation and cross-linking, which result in the measured increase in molecular weight and radius of gyration of the formed polydisperse polymer coils. The formation of nanogels was also observed for Bis solutions at a low concentration. In the case of PEGDA-Bis mixtures, co-polymerisation is suggested as well. At a sufficiently high radiation dose, the formation of a polymer network was observed for both monomers and their mixture. For this reason a sol-gel analysis for PEGDA and Bis was performed gravimetrically and a proposition of an alternative to this method employing a nuclear magnetic resonance technique is made. The two monomers were used for preparation of 3D polymer gel dosimeters having the acronyms PABIG and PABIG nx. The latter is presented for the first time in this work and is a type of the formerly established PABIG polymer gel dosimeter. The elementary characteristics of the new composition are presented, underlining the ease of its preparation, low dose threshold, and slightly increased sensitivity but lower quasi-linear range of dose response in comparison to PABIG.

  7. Comprehensive metabolic profiling of mono- and polyglutamated folates and their precursors in plant and animal tissue using liquid chromatography/negative ion electrospray ionisation tandem mass spectrometry.

    PubMed

    Garratt, Lee C; Ortori, Catharine A; Tucker, Gregory A; Sablitzky, Fred; Bennett, Malcolm J; Barrett, David A

    2005-01-01

    This work reports the use of reversed-phase ion-pair chromatography coupled to electrospray ionisation mass spectrometry for the simultaneous profiling of folate-based metabolites including natural folates, their polyglutamatyl derivatives and their biosynthetic precursors in plant and animal tissue. A simple sample preparation method, using 0.1% citric acid and ascorbic acid in ice-cold methanol, was used to extract and stabilise the folates, and three internal standards were used. Chromatography was on a C18 column using slow gradient elution with a mobile phase consisting of methanol/water with 5 mM dimethylhexylamine. Mass spectrometric detection was performed by multiple reaction monitoring in seven separate time windows in negative ion mode over the 25 min run time. Full, quantitative analysis was obtained for 16 folates and a 'semi-quantitative' analysis was possible for all other folates with up to eight conjugated glutamate residues by reference to structurally related calibration standards. The precision, accuracy and recovery of the method were generally within the accepted guidelines for a quantitative bioanalytical method and the method was linear over the range 0.2 to 10 ng of individual folate per sample. The method was applied to profile mono- and polyglutamated tetrahydrofolates (including subcellular analysis) in a range of plant species, including Arabidopsis, spinach, Brassica and wheat; the technique was also successfully applied to the profiling of folates in mouse tissue. PMID:16047318

  8. The hydroxylase component of soluble methane monooxygenase from Methylococcus capsulatus (Bath) exists in several forms as shown by electrospray-ionisation mass spectrometry.

    PubMed

    Buzy, A; Millar, A L; Legros, V; Wilkins, P C; Dalton, H; Jennings, K R

    1998-06-15

    The hydroxylase of the soluble methane monooxygenase from the bacterium Methylococcus capsulatus (Bath) has been investigated by means of electrospray-ionisation mass spectrometry (ESI-MS) and liquid chromatography ESI-MS (LC/ESI-MS). The hydroxylase is a non-heme diiron protein consisting of three pairs of non-identical subunits (alpha approximately 60 kDa, beta approximately 45 kDa and gamma approximately 20 kDa). Liquid chromatographic separation of the hydroxylase subunits was required before MS analysis in order to detect the alpha-subunit. The masses measured for the three subunits were found to disagree with those calculated from their gene sequences. Experiments involving the use of CNBr and trypsin cleavage followed by LC/ESI-MS and MS/MS analyses permitted the location and correction of errors in the sequences deduced from the use of cDNA. The ESI-MS results also showed that the alpha-subunit of the hydroxylase exists in multiple forms which result from cleavage of the protein. This observation explains a number of enigmatic features of the protein previously reported in the literature and illustrates the pivotal role of ESI-MS in complementing data obtained from molecular biology for the characterisation of the primary sequence of proteins. PMID:9688272

  9. Study of the relative response factors of various gas chromatograph-flame ionisation detector systems for measurement of C2-C9 hydrocarbons in air.

    PubMed

    Slemr, J; Slemr, F; D'Souza, H; Partridge, R

    2004-12-17

    The assumption of an instrument response that is linear with carbon number is frequently used to quantify atmospheric non-methane hydrocarbons (NMHCs) when using gas chromatography (GC) and detection by flame ionisation detector (FID). In order to assess the validity of this widely used method the results of intercomparison measurements by 14 laboratories across Europe were evaluated. The intercomparison measurements were made on synthetic, gravimetrically-prepared, gas mixtures containing 30 hydrocarbons (C2-C9) in the low ppbv range, using various different GC-FID systems. The response per carbon atom of GC-FID systems to individual NMHCs, relative to that of butane, were found to differ by more than 25% across different systems. The differences were mostly caused by analytical errors within particular GC-FID systems and to a more minor degree by systematic deviations related to the molecular structure. (Correction factors due to the molecular structure would lessen the differences, e.g. by about 5% for olefin compounds.) The differences were larger than 10% even after elimination of obvious outliers. Thus, calibration of GC-FID systems with multicomponent NMHC mixtures is found to be essential whenever the accuracy of NMHC measurements is required to be better than about 10%. If calibration by multicomponent gas mixtures is not possible and effective carbon atom response factors are used to quantify the individual NMHC compounds then the particular analytical system should be carefully characterised and its responses to individual compounds be verified. PMID:15633746

  10. Influence of ionisation zone motion in high power impulse magnetron sputtering on angular ion flux and NbO x film growth

    NASA Astrophysics Data System (ADS)

    Franz, Robert; Clavero, César; Kolbeck, Jonathan; Anders, André

    2016-02-01

    The ion energies and fluxes in the high power impulse magnetron sputtering plasma from a Nb target were analysed angularly resolved along the tangential direction of the racetrack. A reactive oxygen-containing atmosphere was used as such discharge conditions are typically employed for the synthesis of thin films. Asymmetries in the flux distribution of the recorded ions as well as their energies and charge states were noticed when varying the angle between mass-energy analyser and target surface. More positively charged ions with higher count rates in the medium energy range of their distributions were detected in +\\mathbf{E}× \\mathbf{B} than in -\\mathbf{E}× \\mathbf{B} direction, thus confirming the notion that ionisation zones (also known as spokes or plasma bunches) are associated with moving potential humps. The motion of the recorded negatively charged high-energy oxygen ions was unaffected. Nb{{\\text{O}}x} thin films at different angles and positions were synthesised and analysed as to their structure and properties in order to correlate the observed plasma properties to the film growth conditions. The chemical composition and the film thickness varied with changing deposition angle, where the latter, similar to the ion fluxes, was higher in +\\mathbf{E}× \\mathbf{B} than in -\\mathbf{E}× \\mathbf{B} direction.

  11. Co-mutation of histone H2AX S139A with Y142A rescues Y142A-induced ionising radiation sensitivity

    PubMed Central

    Brown, James A.L.; Eykelenboom, John K.; Lowndes, Noel F.

    2012-01-01

    Under normal conditions histone H2AX is constitutively phosphorylated on tyrosine (Y) 142 by Williams–Beuren syndrome transcription factor kinase (WSTF). Following DNA double strand breaks (DSB), Y142 is de-phosphorylated and serine (S) 139 is phosphorylated. Here we explored DSB-dependent cross talk between H2AX residues S139 and Y142. H2axY142A mutation resulted in increased sensitivity to ionising radiation (IR), compared to H2axS139A. Interestingly, co-mutation of S139A and Y142A rescued IR sensitivity. The DSB response proteins 53Bp1 and Rad51 were recruited to IR-induced foci (IRIF) in H2axS139A, H2axY142A and H2axS139A/Y142A cells. Our results suggest that H2axY142A IR sensitivity is dependent upon the C-terminal residue, S139. PMID:23772364

  12. Analysis of the monosaccharide composition of water-soluble polysaccharides from Sargassum fusiforme by high performance liquid chromatography/electrospray ionisation mass spectrometry.

    PubMed

    Wu, Xiaodan; Jiang, Wei; Lu, Jiajia; Yu, Ying; Wu, Bin

    2014-02-15

    Sargassum fusiforme (hijiki) is the well-known edible algae, whose polysaccharides have been proved to possess interesting bioactivities like antitumor, antioxidant, antimicrobial and immunomodulatory activities. A facile and sensitive method based on high-performance liquid chromatography method of pre-column derivatization with 1-phenyl-3-methyl-5-pyrazolone (PMP) coupled with electrospray ionisation mass spectrometry (HPLC/ESI-MS) has been established for the analysis of the monosaccharide composition of polysaccharides in S. fusiforme. Monosaccharides have been converted into PMP-labelled derivatives with aqueous ammonia as a catalyst at 70 °C for 30 min. The optimisation of the pre-column derivatization process was studied. The LODs of the monosaccharides were in the range from 0.01 to 0.02 nmol. PMP-labelled mixture of monosaccharides has been well separated by a reverse-phase HPLC and detected by on-line ESI-MS method under optimised conditions. The mobile phase of elution system was chosen as acetonitrile (solvent A) and 20mM aqueous ammonium acetate (solvent B) (pH 3.0) with Zorbax XDB-C18 column at 30 °C for the separation of the monosaccharide derivatives. Identification of the monosaccharides composition was carried out by analysis with mass spectral behaviour and chromatography characteristics of 1-phenyl-3-methyl-5-pyrazolone (PMP) labelled monosaccharides. All PMP-labelled derivatives display high chemical stabilities, whose regular MS fragmentation is specific for reducing labelled sugars. The result showed that the S. fusiforme polysaccharide consisted of mannose, glucose, galactose, xylose, fucose and glucuronic acid or galacturonic acid, or both uronic acids. PMID:24128572

  13. Histidine-containing host-defence skin peptides of anurans bind Cu2+. An electrospray ionisation mass spectrometry and computational modelling study.

    PubMed

    Wang, Tianfang; Andreazza, Hayley J; Pukala, Tara L; Sherman, Patrick J; Calabrese, Antonio N; Bowie, John H

    2011-05-15

    Anuran peptides which contain His, including caerin 1.8 (GLFKVLGSVAKHLLPHVVPVIAEKL-NH(2)), caerin 1.2 (GLLGVLGSVAKHVLPHVVPVIAEHL-NH(2)), Ala(15) maculatin 1.1 (GLFGVLAKVAAHVVAIEHF-NH(2)), fallaxidin 4.1 (GLLSFLPKVIGHLIHPPS-OH), riparin 5.1 (IVSYPDDAGEHAHKMG-NH(2)) and signiferin 2.1 (IIGHLIKTALGMLGL-NH(2)), all form MMet(2+) and (M + Met(2+)-2H(+))(2+) cluster ions (where Met is Cu, Mg and Zn) following electrospray ionisation (ESI) in a Waters QTOF 2 mass spectrometer. Peaks due to Cu(II) complexes are always the most abundant relative to other metal complexes. Information concerning metal(2+) connectivity in a complex has been obtained (at least in part) using b and y fragmentation data from ESI collision-induced dissociation tandem mass spectrometry (CID MS/MS). Theoretical calculations, using AMBER version 10, show that MCu(2+) complexes with the membrane active caerin 1.8, Ala(15) maculatin 1.1 and fallaxidin 4.1 are four-coordinate and approximating square planar, with ligands including His and Lys, together with the carbonyl oxygens of particular backbone amide groups. When binding can occur through two His, or one His and one Lys, the His/Lys ligand structure is the more stable for the studied systems. The three-dimensional (3D) structures of the complexes are always different from the previously determined structures of the uncomplexed model peptides (using 2D nuclear magnetic resonance (NMR) spectroscopy in membrane-mimicking solvents like trifluoroethanol/water). PMID:21488120

  14. The Vitamin D, Ionised Calcium and Parathyroid Hormone Axis of Cerebral Capillary Function: Therapeutic Considerations for Vascular-Based Neurodegenerative Disorders

    PubMed Central

    Lam, Virginie; Takechi, Ryusuke; Pallabage-Gamarallage, Menuka; Giles, Corey; Mamo, John C. L.

    2015-01-01

    Blood-brain barrier dysfunction characterised by brain parenchymal extravasation of plasma proteins may contribute to risk of neurodegenerative disorders, however the mechanisms for increased capillary permeability are not understood. Increasing evidence suggests vitamin D confers central nervous system benefits and there is increasing demand for vitamin D supplementation. Vitamin D may influence the CNS via modulation of capillary function, however such effects may be indirect as it has a central role in maintaining calcium homeostasis, in concert with calcium regulatory hormones. This study utilised an integrated approach and investigated the effects of vitamin D supplementation, parathyroid tissue ablation (PTX), or exogenous infusion of parathyroid hormone (PTH) on cerebral capillary integrity. Parenchymal extravasation of immunoglobulin G (IgG) was used as a marker of cerebral capillary permeability. In C57BL/6J mice and Sprague Dawley rats, dietary vitamin D was associated with exaggerated abundance of IgG within cerebral cortex (CTX) and hippocampal formation (HPF). Vitamin D was also associated with increased plasma ionised calcium (iCa) and decreased PTH. A response to dose was suggested and parenchymal effects persisted for up to 24 weeks. Ablation of parathyroid glands increased CTX- and HPF-IgG abundance concomitant with a reduction in plasma iCa. With the provision of PTH, iCa levels increased, however the PTH treated animals did not show increased cerebral permeability. Vitamin D supplemented groups and rats with PTH-tissue ablation showed modestly increased parenchymal abundance of glial-fibrillary acidic protein (GFAP), a marker of astroglial activation. PTH infusion attenuated GFAP abundance. The findings suggest that vitamin D can compromise capillary integrity via a mechanism that is independent of calcium homeostasis. The effects of exogenous vitamin D supplementation on capillary function and in the context of prevention of vascular

  15. Increasing sensitivity and decreasing spot size using an inexpensive, removable hydrophobic coating for matrix-assisted laser desorption/ionisation plates.

    PubMed

    Owen, Stacey J; Meier, Felix S; Brombacher, Stephan; Volmer, Dietrich A

    2003-01-01

    Spot size reduction and increased detection sensitivity in matrix-assisted laser desorption/ionisation (MALDI) of small molecules are accomplished by using an inexpensive and removable hydrophobic coating for MALDI targets, based on 3M Scotch Gard surface treatment. Several variations in sample preparation were explored, such as surface coating technique, identity of the matrix, solvent composition, and the type of metal support plate used. These were investigated on both uncoated and coated surfaces and their impact on spot size, crystal coverage, and sensitivity is presented here. Additionally, crystallisation behaviour obtained on coated plates is compared with that on uncoated plates using scanning electron microscope analysis. To demonstrate the potential of the new coating technique, erythromycin A and valinomycin are studied to determine the increase in detection sensitivity of coated plates in comparison to uncoated plates, and to reveal the suitability of the plates for application in combined high-performance liquid chromatography/MALDI (HPLC/MALDI), where widely varying solvent compositions and droplet volumes are observed. It is shown that enhancements in detection sensitivities correlate very well with the achieved spot size reduction. The versatility of the coated plates is also exhibited by the ease of removing the surface layer, after which the plates can be rigorously cleaned without worry about damaging the hydrophobic surface, followed by a quick reapplication of new hydrophobic coating material. This makes the non-polar coating superior to more expensive commercial hydrophobic-coated targets, which are much more delicate to clean. Furthermore, cleaning and reapplication eliminate potential carry-over effects and the easy application procedure also makes the fabrication of inexpensive, disposable MALDI targets readily possible. PMID:14587091

  16. On-line measurements of α-pinene ozonolysis products using an atmospheric pressure chemical ionisation ion-trap mass spectrometer

    NASA Astrophysics Data System (ADS)

    Warscheid, Bettina; Hoffmann, Thorsten

    An on-line technique to investigate complex organic oxidation reactions in environmental chamber experiments is presented. The method is based on the direct introduction of the chamber air into an atmospheric pressure ion source of a commercial ion-trap mass spectrometer. To demonstrate the analytical potential of the method (atmospheric pressure chemical ionisation/mass spectrometry, APCI/MS), the ozonolysis of α-pinene was investigated in a series of experiments performed in various sized reaction chambers at atmospheric pressure and 296 K in synthetic air. Investigations were focussed on the influence of the water vapour concentration on the formation of the predominant oxidation product, pinonaldehyde, derived from the α-pinene/ozone reaction. Quantification of pinonaldehyde was achieved by conducting a standard addition technique. The molar yield of pinonaldehyde was found to depend strongly on the actual water vapour concentration between <1 and 80% relative humidity. Starting with an average yield of 0.23±0.05 at dry conditions, pinonaldehyde formation was approximately doubled by reaching a yield of 0.53±0.05 at a relative humidity of around 60%. Furthermore, the formation mechanism of pinonaldehyde was investigated in greater detail using isotopically labelled water. Applying on-line APCI/MS, pinonaldehyde formation under incorporation of 18O was observed, strongly supporting the reaction of the stabilised Criegee radical with water in the gas phase as suggested by Alvarado et al. (Journal of Geophysical Research 103 (1998) 25541-25551). Furthermore, the mass spectra recorded on-line were used to perform a semi-quantitative estimation of the decomposition pathway of the primary ozonide, indicating a branching ratio of 0.35/0.65.

  17. Real-time Measurement of Secondary Organic Aerosols From The Photo-oxidation of Toluene Using Atmospheric Pressure Chemical Ionisation Tandem Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Collin, F.; Arias, M. C.; Merritt, J. V.; Hastie, D. R.

    A system has been developed to study the chemical composition of secondary or- ganic aerosol (SOA) from the photo-oxidation of hydrocarbons using real-time atmo- spheric pressure chemical ionisation triple quadrupole mass spectrometry (APCI/MS- MS) analysis. To complement existing work with a smog chamber, a two-litre dynamic reaction cell has been built. This has a residence time of around two minutes (instead of several hours for smog chamber experiments), thus permitting on-line analysis. Sample gases are introduced into the air stream and irradiated by a 1000 W xenon arc lamp. Af- ter dilution, some of the mixture from the reaction cell is introduced in the MS ion source via a heated probe, with the particle number density being determined by a condensation nucleus counter on the remainder. The focus so far has been on SOA from the photo-oxidation of toluene by HO radicals in presence of NO, with the HO radicals being generated by the photolysis of Isopy- lNitrite (IPN). Prior to performing analyses on the SOA, target compounds (detected in the particulate phase in other studies) were selected and three ions designated to make a fingerprint for each compound. Finally, by using either a denuder, a granu- lar bed diffusion battery or a filter, both gas and particulate phases have been studied independently and compared. Preliminary results show that a number of target compounds, such as methylglyoxylic acid, benzaldehyde or cresol, have been detected in both gas and particulate phases. Most of these compounds appear to be present mainly in the gas phase. An exhaustive identification of organic compounds is a part of the on-going work.

  18. A quick and easy method to identify bacteria by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry.

    PubMed

    Pennanec, Xaviera; Dufour, Alain; Haras, Dominique; Réhel, Karine

    2010-02-01

    Concerns with water quality have increased in recent years, in part due to the more frequent contamination of water by pathogens like E. coli and L. pneumophila. Current methods for the typing of bacteria in water samples are based on culture of samples on specific media. These techniques are time-consuming, subject to the impact of interferents and do not totally meet all the requirements of prevention. There is a need for accurate and rapid identification of these microorganisms. This report deals with the detection of bacteria, more precisely of Legionella spp., and the development of an analytical strategy for a rapid and unambiguous identification of these pathogens in water from diverse origins. Therefore, a protein mass mapping using matrix-assisted laser desorption/ionisation mass spectrometry (MALDI MS) of whole bacteria combined with a home-made database of bacteria spectra is applied. A large variety of different bacteria and microorganisms is used to approach the actual composition of samples with numerous interferents. The objective is to propose a universal method for sampling preparation before MALDI MS analysis and optimised spectrometric conditions for reproducible intense peaks. Several experimental factors known to influence signal quality such as time and media of culture have been studied. The proposed method gives promising results for a sure differentiation of Legionella species and subspecies and a rapid identification of bacteria which are the most dangerous or difficult to eradicate. This method is easy to perform with an excellent reproducibility. The analytical protocol and the corresponding database were validated on samples from different origins (cooling tower, plumbing hot water). PMID:20049880

  19. Matrix-assisted laser desorption/ionisation-time of flight mass spectrometry: rapid identification of bacteria isolated from patients with cystic fibrosis.

    PubMed

    Baillie, S; Ireland, K; Warwick, S; Wareham, D; Wilks, M

    2013-01-01

    Despite extensive research into the diagnosis and management of cystic fibrosis (CF) over the past decades, sufferers still have a median life expectancy of less than 37 years. Respiratory tract infections have a significant role in increasing the morbidity and mortality of patients with CF via a progressive decline in lung function. Rapid identification of organisms recovered from CF sputum is necessary for effective management of respiratory tract infections; however, standard techniques of identification are slow, technically demanding and expensive. The aim of this study is to asses the suitability of matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF MS) in identifying bacteria isolated from the respiratory tract of patients with CF, and is assessed by testing the accuracy of MALDI-TOF MS in identifying samples from a reference collection of rare CF strains in conjunction with comparing MALDI-TOF MS and standard techniques in identifying clinical isolates from sputum samples of CF patients. MALDI-TOF MS accurately identified 100% of isolates from the reference collection of rare CF pathogens (EuroCare CF collection). The isolate identification given by MALDI-TOF MS agreed with that given by standard techniques for 479/481 (99.6%) clinical isolates obtained from respiratory samples provided by patients with CE In two (0.4%) of 481 samples there was a discrepancy in identification between MALDI-TOF MS and standard techniques. One organism was identified as Pseudomonas aeruginosa by MALDI-TOF but could only be identified by the laboratory's standard methods as of the Pseudomonas genus. The second organism was identified as P. beteli by MALDI-TOF MS and Stenotrophomonas maltophilia by standard methods. This study shows that MALDI-TOF MS is superior to standard techniques in providing cheap, rapid and accurate identification of CF sputum isolates. PMID:24400425

  20. Chemical study of triterpenoid resinous materials in archaeological findings by means of direct exposure electron ionisation mass spectrometry and gas chromatography/mass spectrometry.

    PubMed

    Modugno, Francesca; Ribechini, Erika; Colombini, Maria Perla

    2006-01-01

    A systematic study of standard triterpenes (alpha-amyrine, oleanolic acid, betulin, lupeol, betulinic acid and lupenone) and of raw resinous materials (frankincense resin, mastic resin and birch bark pitch) was performed using direct exposure electron ionisation mass spectrometry (DE-MS) and gas chromatography/mass spectrometry (GC/MS). DE-MS provides a mass spectral fingerprint of organic materials in a few minutes which highlights the compounds that are the main components in the sample. The application of principal component analysis (PCA) on DE-MS data in the mass ranges m/z 181-260 and m/z 331-500, corresponding to the fragmentation of triterpenoid molecules, enabled us to distinguish between different triterpenoid materials such as mastic resin, frankincense resin and birch bark pitch, and to graphically plot the resinous substances in three separate clusters, retaining 89% of the total variance. GC/MS analysis of the same materials has permitted us to elucidate in detail the molecular composition and to identify minor components and species that act as markers of the degradation undergone by the materials. The paper also reports the results for the organic residues contained in an Egyptian censer (5th-7th century AD) which was recovered in the excavation of the Necropolis of Antinoe (Egypt), and for the hafting material found on a Palaeolithic tool recovered at the site of Campitello (Arezzo, Tuscany), dating back to the Mid-Pleistocene period. Although DE-MS was found to be a fast analytical tool, it failed to give any information on the presence of less abundant compounds when applied to mixtures of different materials: only mastic resin was found in the residues from the Roman censer, whereas GC/MS analysis identified the presence of a vegetable oil from Brassicaceae seeds and Pinaceae resin. Birch bark pitch as a pure material was identified in the sample from the Palaeolithic flint flake using both procedures. PMID:16676320

  1. Oral brush biopsy analysis by matrix assisted laser desorption/ionisation-time of flight mass spectrometry profiling--a pilot study.

    PubMed

    Remmerbach, Torsten W; Maurer, Katja; Janke, Sebastian; Schellenberger, Wolfgang; Eschrich, Klaus; Bertolini, Julia; Hofmann, Herbert; Rupf, Stefan

    2011-04-01

    Oral squamous cell carcinomas (OSCCs) often present as advanced tumours requiring aggressive local and regional therapy and result in significant functional impairment. The objective is to develop pre-symptomatic screening detection of OSCC by a brush biopsy method which is less invasive than the conventional biopsy for histology. Given the molecular heterogeneity of oral cancer, it is unlikely that even a panel of tumour markers would provide accurate diagnosis. Therefore, approaches such as the matrix-assisted-laser-desorption/ionisation-time-of-flight-mass-spectrometry (MALDI-TOF-MS) allow several biomarkers or peptide profile patterns to be simultaneously assessed. Brush biopsies from 27 patients with histology-proven OSCCs plus 40 biopsies from 10 healthy controls were collected. MALDI-TOF-MS profiling was performed and additional statistical analysis of the data was used to classify the disease status according to the biological behaviour of the lesion. For classification a support vector machine algorithm was trained using spectra of brush biopsy samples to distinguish healthy control patients from patients with histology-proven OSCC. MALDI-TOF-MS was able to distinguish between healthy patients and OSCC patients with a sensitivity of 100% and specificity of 93%. In summary, MALDI-TOF-MS in combination with sophisticated bioinformatic methods can distinguish OSCC patients from non-cancer controls with excellent sensitivity and specificity. Further improvement and validation of this approach is necessary to determine its feasibility to assist the pre-symptomatic detection of head and neck cancer screening in routine daily practice. PMID:21354855

  2. The level of serum ionised calcium, aspartate aminotransferase, insulin, glucose, betahydroxybutyrate concentrations and blood gas parameters in cows with left displacement of abomasum.

    PubMed

    Sen, I; Ok, M; Coskun, A

    2006-01-01

    The purpose of this study was to determine concentrations of serum glucose, aspartate aminotransferase (AST), insulin, beta-hydroxybutyrate (BOH) and ionised calcium (Ica) in dairy cows with left displaced abomasum (LDA) and to compare these parameters before and after surgical correction of LDA. Eighteen Swiss-Holstein dairy cows with LDA were used in this study. Clinically healthy post parturient cows (n: 10) from a local dairy farm were used as control group. Blood samples were collected from the jugular vein from all the cows. Surgery was performed in cows with LDA. Blood samples from cows with LDA were collected 24 hours after surgery. The abomasum was repositioned followed by an omentopexy. Six of the 18 cows with LDA had clinical ketosis as detected with urine dipstick. The mean concentrations of insulin, BOH, glucose and AST in cows with LDA at admission time were increased compared with the healthy cows. But the mean concentration of ICa at admission time was slightly decreased compared with healthy cows. The mean BOH concentration was decreased 24 hours following surgery compared with values on admission time. However, the mean serum AST levels were increased both at admission time and 24 hours after surgery compared with healthy cows. The levels of blood gas parameters in cows with LDA were not significantly different in comparison with healthy cows, although hyperbasemia in six of 18 cows with LDA was determined. In conclusion, the results of this study indicated that serum insulin, glucose, AST and BOH levels were increased in dairy cows with LDA. Serum BOH and ICa levels were decreased 24 hours after surgery compared with values on admission time. All cows with LDA used in this study had subclinical/clinical ketosis. We could say that ketosis might be a risk factor for the displacement of the abomasum. PMID:17203740

  3. In situ formation and characterisation of singly ionised atomic europium in rare gas matrices—Luminescence spectroscopy and MP2 calculations

    SciTech Connect

    Byrne, Owen; Davis, Barry; McCaffrey, John G.

    2015-02-07

    , providing a temporary trap for the ionised electron in the matrices.

  4. Rapid identification of Burkholderia mallei and Burkholderia pseudomallei by intact cell Matrix-assisted Laser Desorption/Ionisation mass spectrometric typing

    PubMed Central

    2012-01-01

    Background Burkholderia (B.) pseudomallei and B. mallei are genetically closely related species. B. pseudomallei causes melioidosis in humans and animals, whereas B. mallei is the causative agent of glanders in equines and rarely also in humans. Both agents have been classified by the CDC as priority category B biological agents. Rapid identification is crucial, because both agents are intrinsically resistant to many antibiotics. Matrix-assisted laser desorption/ionisation mass spectrometry (MALDI-TOF MS) has the potential of rapid and reliable identification of pathogens, but is limited by the availability of a database containing validated reference spectra. The aim of this study was to evaluate the use of MALDI-TOF MS for the rapid and reliable identification and differentiation of B. pseudomallei and B. mallei and to build up a reliable reference database for both organisms. Results A collection of ten B. pseudomallei and seventeen B. mallei strains was used to generate a library of reference spectra. Samples of both species could be identified by MALDI-TOF MS, if a dedicated subset of the reference spectra library was used. In comparison with samples representing B. mallei, higher genetic diversity among B. pseudomallei was reflected in the higher average Eucledian distances between the mass spectra and a broader range of identification score values obtained with commercial software for the identification of microorganisms. The type strain of B. pseudomallei (ATCC 23343) was isolated decades ago and is outstanding in the spectrum-based dendrograms probably due to massive methylations as indicated by two intensive series of mass increments of 14 Da specifically and reproducibly found in the spectra of this strain. Conclusions Handling of pathogens under BSL 3 conditions is dangerous and cumbersome but can be minimized by inactivation of bacteria with ethanol, subsequent protein extraction under BSL 1 conditions and MALDI-TOF MS analysis being faster than

  5. Homogeneous sample preparation for automated high throughput analysis with matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry.

    PubMed

    Onnerfjord, P; Ekström, S; Bergquist, J; Nilsson, J; Laurell, T; Marko-Varga, G

    1999-01-01

    This work presents a simple method for obtaining homogeneous sample surfaces in matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS) for the automated analysis of peptides and proteins. The sample preparation method is based on applying the sample/matrix mixture onto a pre-deposited highly diluted matrix spot. The pre-deposited crystals act as seeds for the new sample containing crystals which become much smaller in size and more evenly distributed than with conventional methods. This 'seed-layer' method was developed, optimised and compared with the dried-droplet method using peptides and proteins in the 1000-20,000 Da range. The seed-layer method increases the surface homogeneity, spot to spot reproducibility and sample washability as compared with the commonly used dried-droplet method. This methodology is applicable to alpha-cyanohydroxycinnamic acid, sinapinic acid and ferulic acid, which all form homogeneous crystal surfaces. Within-spot variation and between-spot variation was investigated using statistics at a 95% confidence level (n = 36). The statistical values were generated from more than 5000 data points collected from 500 spectra. More than 90% of the sample locations results in high intensity spectra with relatively low standard deviations (RSDs). Typically obtained data showed an RSD of 19-35% within a sample spot as well as in-between spots for proteins, and an RSD of < or = 50% for peptides. Linear calibration curves were obtained within one order of magnitude using internal calibration with a point-RSD of 3% (n = 10). The sample homogeneity allows mass spectra (average of 16 laser shots) to be obtained on each individual sample within 15 sec, whereby a 100 spot target plate can be run in 25 min. High density target plates using the seed-layer method were prepared by spotting approximately 100 picoliter droplets onto the target, resulting in sample spots < or = 500 microns in diameter using a flow

  6. Ionisation induced collapse of minihaloes

    NASA Astrophysics Data System (ADS)

    Back, Trevor

    2013-08-01

    In order to analyse the turbine blade life, the damage due to the combined thermal and mechanical loads should be adequately accounted for. This is more challenging when detailed component geometry is limited. Therefore, a compromise between the level of geometric detail and the complexity of the lifing method to be implemented would be necessary. This research focuses on how the life assessment of aero engine turbine blades can be done, considering the balance between available design inputs and adequate level of fidelity. Accordingly, the thesis contributes to developing a generic turbine blade lifing method that is based on the engine thermodynamic cycle; as well as integrating critical design/technological factors and operational parameters that influence the aero engine blade life. To this end, thermo-mechanical fatigue was identified as the critical damage phenomenon driving the life of the turbine blade.. The developed approach integrates software tools and numerical models created using the minimum design information typically available at the early design stages. Using finite element analysis of an idealised blade geometry, the approach captures relevant impacts of thermal gradients and thermal stresses that contribute to the thermo-mechanical fatigue damage on the gas turbine blade. The blade life is evaluated using the Neu/Sehitoglu thermo-mechanical fatigue model that considers damage accumulation due to fatigue, oxidation, and creep. The leading edge is examined as a critical part of the blade to estimate the damage severity for different design factors and operational parameters. The outputs of the research can be used to better understand how the environment and the operating conditions of the aircraft affect the blade life consumption and therefore what is the impact on the maintenance cost and the availability of the propulsion system. This research also finds that the environmental (oxidation) effect drives the blade life and the blade coolant side was the critical location. Furthermore, a parametric and sensitivity study of the Neu/Sehitoglu model parameters suggests that in addition to four previously reported parameters, the sensitivity of the phasing to oxidation damage would be critical to overall blade life..

  7. Determination and separation of bisphenol A, phthalate metabolites and structural isomers of parabens in human urine with conventional high-pressure liquid chromatography combined with electrospray ionisation tandem mass spectrometry.

    PubMed

    Myridakis, Antonis; Balaska, Eirini; Gkaitatzi, Christina; Kouvarakis, Antonis; Stephanou, Euripides G

    2015-03-01

    Phthalates, bisphenol A (BPA) and parabens (PBs), organic chemicals widely used in everyday products, are considered to be endocrine disruptors. We propose a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of seven phthalate metabolites, six PBs and BPA in human urine. All three categories of the above endocrine disruptors were simultaneously extracted from 1 mL of human urine using solid phase extraction. In addition, with a conventional reversed phase LC column, we achieved for the first time the separation of three pairs of structural isomers, namely iso-/n-butyl paraben, propyl paraben and monobutyl phthalate. LC-MS/MS was operated and tested in both electrospray ionisation (ESI) and atmospheric pressure chemical ionisation (APCI). ESI was selected for the analysis due to its superior stability and repeatability. The method limit of detection (mLOD), achieved for a single set of high-performance LC conditions, ranged from 0.01 to 0.84 ng/mL for phthalate metabolites, from 0.06 to 0.24 ng/mL for PBs and was 2.01 ng/mL for BPA. Derivatisation of BPA with dansyl chloride lowered its mLOD to 0.007 ng/mL. Blank contamination was non-detectable. The present method was successfully applied for the analysis of the above-mentioned compounds in 80 male human urine samples. PMID:25644523

  8. Real-time analysis of aromatics in combustion engine exhaust by resonance-enhanced multiphoton ionisation time-of-flight mass spectrometry (REMPI-TOF-MS): a robust tool for chassis dynamometer testing.

    PubMed

    Adam, T W; Clairotte, M; Streibel, T; Elsasser, M; Pommeres, A; Manfredi, U; Carriero, M; Martini, G; Sklorz, M; Krasenbrink, A; Astorga, C; Zimmermann, R

    2012-07-01

    Resonance-enhanced multiphoton ionisation time-of-flight mass spectrometry (REMPI-TOF-MS) is a robust method for real-time analysis of monocyclic and polycyclic aromatic hydrocarbons in complex emissions. A mobile system has been developed which enables direct analysis on site. In this paper, we utilize a multicomponent calibration scheme based on the analytes' photo-ionisation cross-sections relative to a calibrated species. This allows semi-quantification of a great number of components by only calibrating one compound of choice, here toluene. The cross-sections were determined by injecting nebulised solutions of aromatic compounds into the TOF-MS ion source with the help of a HPLC pump. Then, REMPI-TOF-MS was implemented at various chassis dynamometers and test cells and the exhaust of the following vehicles and engines investigated: a compression ignition light-duty (LD) passenger car, a compression ignition LD van, two spark ignition LD passenger cars, 2 two-stroke mopeds, and a two-stroke engine of a string gas trimmer. The quantitative time profiles of benzene are shown. The results indicate that two-stroke engines are a significant source for toxic and cancerogenic compounds. Air pollution and health effects caused by gardening equipment might still be underestimated. PMID:22644155

  9. Quaternary structure of the extracellular haemoglobin of the lugworm Arenicola marina: a multi-angle-laser-light-scattering and electrospray-ionisation-mass-spectrometry analysis.

    PubMed

    Zal, F; Green, B N; Lallier, F H; Vinogradov, S N; Toulmond, A

    1997-01-15

    To elucidate the quaternary structure of the extracellular haemoglobin (Hb) of the marine polychaete Arenicola marina (lugworm) it was subjected to multi-angle laser-light scattering (MALLS) and to electrospray-ionisation mass spectrometry (ESI-MS). It was also subjected to SDS/PAGE analysis for comparative purposes. MALLS analysis gave a molecular mass of 3648 +/- 24 kDa and a gyration radius of 11.3 +/- 1.7 nm. Maximum entropy analysis of the multiply charged electrospray spectra of the native, dehaemed, reduced and carbamidomethylated Hb forms, provided its complete polypeptide chain and subunit composition. We found, in the reduced condition, eight globin chains of molecular masses 15952.5 Da (a1), 15974.8 Da (a2), 15920.9 Da (b1), 16020.1 Da (b2), 16036.2 Da (b3), 16664.8 Da (c), 16983.2 Da (d1), 17033.1 Da (d2) and two linker chains L1, 25174.1 Da, and L2, 26829.7 Da. In the native Hb, chains b, c, d occur as five disulphide-bonded trimer subunits T with masses of 49560.4 Da (T1), 49613.9 Da (T2), 49658.6 Da (T3), 49706.8 Da (T4), 49724.5 Da (T5). Linker chains L1 and L2 occur as one disulphide-bonded homodimer 2L1 (D1) of 50323.1 Da and one disulphide-bonded heterodimer L1-L2 (D2) of 51 981.5 Da. Polypeptide chains a and d possess one free cysteine residue and chains d possess an unusual total of five cysteine residues. Semi-quantitative analysis of ESI-MS data allowed us to propose the following model for the one-twelfth protomer: [(3a1)(3a2)2T] (T corresponding to either T3, T4 or T5). From electron micrograph data T1 and T2 are probably located at the centre of the molecule as mentioned in previous studies. The Hb would thus be composed of 198 polypeptide chains with 156 globin chains and 42 linker chains, each twelfth being in contact with 3.5 linker subunits, providing a total mass of 3682 kDa including haems in agreement with the experimental molecular mass determined by MALLS. From ESI-MS relative intensities and the model proposed above, the globin

  10. Profile of phenolic compounds of Brazilian virgin olive oils by rapid resolution liquid chromatography coupled to electrospray ionisation time-of-flight mass spectrometry (RRLC-ESI-TOF-MS).

    PubMed

    Ballus, Cristiano Augusto; Quirantes-Piné, Rosa; Bakhouche, Abdelhakim; da Silva, Luiz Fernando de Oliveira; de Oliveira, Adelson Francisco; Coutinho, Enilton Fick; da Croce, Dorli Mario; Segura-Carretero, Antonio; Godoy, Helena Teixeira

    2015-03-01

    In recent years, agronomical researchers began to cultivate several olive varieties in different regions of Brazil to produce virgin olive oil (VOO). Because there has been no reported data regarding the phenolic profile of the first Brazilian VOO, the aim of this work was to determine phenolic contents of these samples using rapid-resolution liquid chromatography coupled to electrospray ionisation time-of-flight mass spectrometry. 25 VOO samples from Arbequina, Koroneiki, Arbosana, Grappolo, Manzanilla, Coratina, Frantoio and MGS Mariense varieties from three different Brazilian states and two crops were analysed. It was possible to quantify 19 phenolic compounds belonging to different classes. The results indicated that Brazilian VOOs have high total phenolic content because the values were comparable with those from high-quality VOOs produced in other countries. VOOs from Coratina, Arbosana and Grappolo presented the highest total phenolic content. These data will be useful in the development and improvement of Brazilian VOO. PMID:25306359

  11. A peptidomic approach for monitoring and characterising peptide cyanotoxins produced in Italian lakes by matrix-assisted laser desorption/ionisation and quadrupole time-of-flight mass spectrometry.

    PubMed

    Ferranti, Pasquale; Nasi, Antonella; Bruno, Milena; Basile, Adriana; Serpe, Luigi; Gallo, Pasquale

    2011-05-15

    In recent years, the occurrence of cyanobacterial blooms in eutrophic freshwaters has been described all over the world, including most European countries. Blooms of cyanobacteria may produce mixtures of toxic secondary metabolites, called cyanotoxins. Among these, the most studied are microcystins, a group of cyclic heptapeptides, because of their potent hepatotoxicity and activity as tumour promoters. Other peptide cyanotoxins have been described whose structure and toxicity have not been thoroughly studied. Herein we present a peptidomic approach aimed to characterise and quantify the peptide cyanotoxins produced in two Italian lakes, Averno and Albano. The procedure was based on matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry mass spectrometry (MALDI-TOF-MS) analysis for rapid detection and profiling of the peptide mixture complexity, combined with liquid chromatography/electrospray ionisation quadrupole time-of- flight tandem mass spectrometry (LC/ESI-Q-TOF-MS/MS) which provided unambiguous structural identification of the main compounds, as well as accurate quantitative analysis of microcystins. In the case of Lake Averno, a novel variant of microcystin-RR and two novel anabaenopeptin variants (Anabaenopeptins B(1) and Anabaenopeptin F(1)), presenting homoarginine in place of the commonly found arginine, were detected and characterised. In Lake Albano, the peculiar peptide patterns in different years were compared, as an example of the potentiality of the peptidomic approach for fast screening analysis, prior to fine structural analysis and determination of cyanotoxins, which included six novel aeruginosin variants. This approach allows for wide range monitoring of cyanobacteria blooms, and to collect data for evaluating possible health risks to consumers, through the panel of the compounds produced along different years. PMID:21488115

  12. Retention of ionisable compounds on high-performance liquid chromatography. XV. Estimation of the pH variation of aqueous buffers with the change of the acetonitrile fraction of the mobile phase.

    PubMed

    Subirats, Xavier; Bosch, Elisabeth; Rosés, Martí

    2004-12-01

    The most commonly used mobile phases in reversed-phase high-performance liquid chromatography (RP-HPLC) are hydro-organic mixtures of an aqueous buffer and an organic modifier. The addition of this organic solvent to buffered aqueous solutions involves a variation of the buffer properties (pH and buffer capacity). In this paper, the pH variation is studied for acetic acid-acetate, phosphoric acid-dihydrogenphosphate-hydrogenphosphate, citric acid-dihydrogencitrate-citrate, and ammonium-ammonia buffers. The proposed equations allow pH estimation of acetonitrile-water buffered mobile phases up to 60% (v/v) of organic modifier and initial aqueous buffer concentrations between 0.001 and 0.1 mol L(-1), from the initial aqueous pH. The estimated pH variation of the mobile phase and the pKa variation of the analytes allow us to predict the degree of ionisation of the analytes and from this and analyte hydrophobicities, to interpret the relative retention and separation of analyte mixtures. PMID:15628122

  13. Rapid characterisation and comparison of saponin profiles in the seeds of Korean Leguminous species using ultra performance liquid chromatography with photodiode array detector and electrospray ionisation/mass spectrometry (UPLC-PDA-ESI/MS) analysis.

    PubMed

    Ha, Tae Joung; Lee, Byong Won; Park, Ki Hun; Jeong, Seong Hun; Kim, Hyun-Tae; Ko, Jong-Min; Baek, In-Youl; Lee, Jin Hwan

    2014-03-01

    The present work was reported on investigation of saponin profiles in nine different legume seeds, including soybean, adzuki bean, cowpea, common bean, scarlet runner bean, lentil, chick pea, hyacinth bean, and broad bean using ultra performance liquid chromatography with photodiode array detector and electrospray ionisation/mass spectrometry (UPLC-PDA-ESI/MS) technique. A total of twenty saponins were characterised under rapid and simple conditions within 15min by the 80% methanol extracts of all species. Their chemical structures were elucidated as soyasaponin Ab (1), soyasaponin Ba (2), soyasaponin Bb (3), soyasaponin Bc (4), soyasaponin Bd (5), soyasaponin αg (6), soyasaponin βg (7), soyasaponin βa (8), soyasaponin γg (9), soyasaponin γa (10), azukisaponin VI (11), azukisaponin IV (12), azukisaponin II (13), AzII (14), AzIV (15), lablaboside E (16), lablaboside F (17), lablaboside D (18), chikusetusaponin IVa (19), and lablab saponin I (20). The individual and total saponin compositions exhibited remarkable differences in all legume seeds. In particular, soyasaponin βa (8) was detected the predominant composition in soybean, cowpea, and lentil with various concentrations. Interestingly, soybean, adzuki bean, common bean, and scarlet runner bean had high saponin contents, while chick pea and broad bean showed low contents. PMID:24176342

  14. Supersonic molecular beam-hyperthermal surface ionisation coupled with time-of-flight mass spectrometry applied to trace level detection of polynuclear aromatic hydrocarbons in drinking water for reduced sample preparation and analysis time.

    PubMed

    Davis, S C; Makarov, A A; Hughes, J D

    1999-01-01

    Analysis of sub-ppb levels of polynuclear aromatic hydrocarbons (PAHs) in drinking water by high performance liquid chromatography (HPLC) fluorescence detection typically requires large water samples and lengthy extraction procedures. The detection itself, although selective, does not give compound identity confirmation. Benchtop gas chromatography/mass spectrometry (GC/MS) systems operating in the more sensitive selected ion monitoring (SIM) acquisition mode discard spectral information and, when operating in scanning mode, are less sensitive and scan too slowly. The selectivity of hyperthermal surface ionisation (HSI), the high column flow rate capacity of the supersonic molecular beam (SMB) GC/MS interface, and the high acquisition rate of time-of-flight (TOF) mass analysis, are combined here to facilitate a rapid, specific and sensitive technique for the analysis of trace levels of PAHs in water. This work reports the advantages gained by using the GC/HSI-TOF system over the HPLC fluorescence method, and discusses in some detail the nature of the instrumentation used. PMID:10097402

  15. An efficient method for the simultaneous determination of furan, 2-methylfuran and 2-pentylfuran in fruit juices by headspace solid phase microextraction and gas chromatography-flame ionisation detector.

    PubMed

    Hu, Gaofei; Zhu, Yan; Hernandez, Marta; Koutchma, Tatiana; Shao, Suqin

    2016-02-01

    A headspace solid phase microextraction (HS-SPME) procedure followed by gas chromatography-flame ionisation detector (GC-FID) analysis was developed and validated for the simultaneous analysis of furan, 2-methylfuran and 2-pentylfuran from juice samples. Extraction at 32 °C for 20 min with stirring at 600 rpm and NaCl concentration 15% (W/V) was the optimal HS-SPME condition for all the three compounds by using a carboxen/polydimethylsiloxane fused silica fibre (75 μm). The extracted compounds were base line separated on a SPB-1 GC column within 12 min. The relative standard deviations of all analytes were less than 6.7%. The recovery rates were between 90.2% and 110.1%. The limits of detection and limits of quantification were 0.056-0.23 ng/mL and 0.14-0.76 ng/mL, respectively. The results showed that the developed method was sensitive, precise, accurate and robust for the determination of furan, 2-methylfuran and 2-pentylfuran in complex matrices without interferences from other components. PMID:26304314

  16. Characterisation of ship diesel primary particulate matter at the molecular level by means of ultra-high-resolution mass spectrometry coupled to laser desorption ionisation--comparison of feed fuel, filter extracts and direct particle measurements.

    PubMed

    Rüger, Christopher P; Sklorz, Martin; Schwemer, Theo; Zimmermann, Ralf

    2015-08-01

    In this study, positive-mode laser desorption-ionisation ultra-high-resolution mass spectrometry (LDI-FT-ICR-MS) was applied to study combustion aerosol samples obtained from a ship diesel engine as well as the feed fuel, used to operate the engine. Furthermore, particulate matter was sampled from the exhaust tube using an impactor and analysed directly from the impaction foil without sample treatment. From the high percentage of shared sum formula as well as similarities in the chemical spread of aerosol and heavy fuel oil, results indicate that the primary aerosol mainly consists of survived, unburned species from the feed fuel. The effect of pyrosynthesis could be observed and was slightly more pronounced for the CH-class compared to other compound classes, but in summary not dominant. Alkylation pattern as well as the aromaticity distribution, using the double bond equivalent, revealed a shift towards lower alkylation state for the aerosol. The alkylation pattern of the most dominant series revealed a higher correlation between different aerosol samples than between aerosol and feed samples. This was confirmed by cluster analysis. Overall, this study shows that LDI-FT-ICR-MS can be successfully applied for the analysis of combustion aerosol at the molecular level and that sum formula information can be used to identify chemical differences between aerosol and fuel as well as between different size fractions of the particulate matter. PMID:25585886

  17. Analysis of the volatile compounds of Teucrium flavum L. subsp. flavum (Lamiaceae) by headspace solid-phase microextraction coupled to gas chromatography with flame ionisation and mass spectrometric detection.

    PubMed

    Sagratini, Gianni; Maggi, Filippo; Bílek, Tomas; Papa, Fabrizio; Vittori, Sauro

    2012-01-01

    In this study, a headspace solid-phase microextraction (HS-SPME) method, in combination with gas chromatography flame ionisation detector and gas chromatography-mass spectrometry, has been developed for use in the analysis of the volatile compounds of Teucrium flavum L. subsp. flavum, a plant whose particular fragrance is used in the preparation of flavoured wines, bitters and liqueurs, or as a substitute for hops in the flavouring of beer. The tested fibres were 100 µm poly(dimethylsiloxane) (PDMS), the 65 µm PDMS/divinylbenzene (DVB) and 50/30 µm DVB-carboxen-PDMS. The best fibre was found to be PDMS when working in the following conditions: 60°C temperature, 30 min extraction time, 30 mg sample amount, 1 mm sample particle size. The HS-SPME method permitted the identification (95.8-97.8%) of 76 (dry) and 66 (fresh) different volatiles. In addition, we discovered that the presence of water in the sample can enhance the absolute quantity of alcoholic compounds such as 1-octen-3-ol and reduce the presence of esters such as methyl geranate. PMID:22077422

  18. Doubly electron-attached and doubly ionised equation-of-motion coupled-cluster methods with full and active-space treatments of 4-particle-2-hole and 4-hole-2-particle excitations: the role of orbital choices

    NASA Astrophysics Data System (ADS)

    Shen, Jun; Piecuch, Piotr

    2014-03-01

    We have recently developed the full and active-space doubly electron-attached (DEA) and doubly ionised (DIP) equation-of-motion coupled-cluster (EOMCC) methods with up to 4-particle-2-hole (4p-2h) and 4-hole-2-particle (4h-2p) excitations. By examining the low-lying singlet and triplet states of the methylene, (HFH)-, and trimethylenemethane biradicals, and a few different types of molecular orbitals (MOs) to describe the corresponding wave functions, including the restricted or restricted open-shell Hartree-Fock orbitals of the target N-electron species and their counterparts associated with the (N ∓ 2)-electron reference systems, we demonstrate that the DEA- and DIP-EOMCC approaches with the full and active-space treatments of 4p-2h and 4h-2p excitations provide high-accuracy results which are not only in perfect agreement with one another, but also practically insensitive to the choice of the underlying MO basis. This should be contrasted with the DEA- and DIP-EOMCC methods truncated at 3p-1h/3h-1p excitations, which are generally less accurate and more sensitive to the types of orbitals used in the calculations.

  19. The Insidious Nature of 'Hard-Core' Alternative Conceptions: Implications for the constructivist research programme of patterns in high school students' and pre-service teachers' thinking about ionisation energy

    NASA Astrophysics Data System (ADS)

    Taber, Keith S.; Tan, Kim Chwee Daniel

    2011-01-01

    The present study contributes to the constructivist research programme (RP) into learning science by comparing patterns in responses from two groups of learners-senior high school students and pre-service teachers-in the same educational context (Singapore), to a diagnostic instrument relating to the topic of ionisation energies. This topic is currently included in the curriculum for 16- to 19-year-old students studying chemistry in Singapore (and elsewhere). The comparison shows that: (1) although graduate pre-service teachers offered some types of incorrect responses less frequently than high school students; (2) they retained high levels of alternative conceptions commonly found among high school students; and (3) of particular note, certain alternative conceptions were found to be more common among the graduates. This suggests the intuitive appeal of certain alternative conceptions is such that they can readily be reproduced down 'generations' of learners. The findings are explored in terms of a range of conceptual resources that have been developed within the constructivist RP. The analysis suggests that the curriculum sets out inappropriate target knowledge for senior high school students, given the nature of the subject matter and the prior learning of the students. It is also suggested that it may be fruitful to consider conceptual learning in terms analogous to the RP found in science, and that from this perspective certain insidious alternative conceptions can be understood as derived from commitments that are taken for granted and protected from explicit challenge by a protective belt of refutable auxiliary conceptions.

  20. On-line process monitoring of coffee roasting by resonant laser ionisation time-of-flight mass spectrometry: bridging the gap from industrial batch roasting to flavour formation inside an individual coffee bean.

    PubMed

    Hertz-Schünemann, R; Dorfner, R; Yeretzian, C; Streibel, T; Zimmermann, R

    2013-12-01

    Resonance-enhanced multiphoton ionisation time-of-flight mass spectrometry (REMPI-TOFMS) enables the fast and sensitive on-line monitoring of volatile organic compounds (VOC) formed during coffee roasting. On the one hand, REMPI-TOFMS was applied to monitor roasting gases of an industrial roaster (1500 kg/h capacity), with the aim of determining the roast degree in real-time from the transient chemical signature of VOCs. On the other hand, a previously developed μ-probe sampling device was used to analyse roasting gases from individual coffee beans. The aim was to explore fundamental processes at the individual bean level and link these to phenomena at the batch level. The pioneering single-bean experiments were conducted in two configurations: (1) VOCs formed inside a bean were sampled in situ, i.e. via a drilled μ-hole, from the interior, using a μ-probe (inside). (2) VOCs were sampled on-line in close vicinity of a single coffee bean's surface (outside). The focus was on VOCs originating from hydrolysis and pyrolytic degradation of chlorogenic acids, like feruloyl quinic acid and caffeoyl quinic acid. The single bean experiments revealed interesting phenomena. First, differences in time-intensity profiles between inside versus outside (time shift of maximum) were observed and tentatively linked to the permeability of the bean's cell walls material. Second, sharp bursts of some VOCs were observed, while others did exhibit smooth release curves. It is believed that these reflect a direct observation of bean popping during roasting. Finally, discrimination between Coffea arabica and Coffea canephora was demonstrated based on high-mass volatile markers, exclusively present in spectra of Coffea arabica. PMID:24338878

  1. Characterisation of intact recombinant human erythropoietins applied in doping by means of planar gel electrophoretic techniques and matrix-assisted laser desorption/ionisation linear time-of-flight mass spectrometry.

    PubMed

    Stübiger, Gerald; Marchetti, Martina; Nagano, Marietta; Reichel, Christian; Gmeiner, Günter; Allmaier, Günter

    2005-01-01

    Our experiments show that it is possible to detect different types of recombinant human erythropoietins (rhEPOs), EPO-alpha, EPO-beta and novel erythropoesis stimulating protein (NESP), based on exact molecular weight (MW) determination by matrix-assisted laser desorption/ionisation mass spectrometry (MALDI-MS) applying a high-resolution time-of-flight (TOF) mass analyser in the linear mode. Detection limits for the highly purified, intact glycoproteins were achievable in the low fmol range (25-50 fmol) using a sample preparation method applying a hydrophobic sample support (DropStop) as MALDI target surface. These results are very promising for the development of highly sensitive detection methods for a direct identification of rhEPO after enrichment from human body fluids. During our investigation we were able to differentiate EPO-alpha, EPO-beta and NESP based on distinct molecular substructures at the protein level by specific enzymatic reactions. MW determination of the intact molecules by high resolving one-dimensional sodium dodecyl sulfate /polyacrylamide gel electrophoresis (1D SDS-PAGE) and isoform separation by planar isoelectric focusing (IEF) was compared with MALDI-MS data. Migration differences between the rhEPOs were observed from gel electrophoresis, whereby MWs of 38 kDa in the case of EPO-alpha/beta and 49 kDa for NESP could be estimated. In contrast, an exact MW determination by MALDI-MS based on internal calibration revealed average MWs of 29.8 +/- 0.3 kDa for EPO-alpha/beta and 36.8 +/- 0.4 kDa for NESP. IEF separation of the intact rhEPOs revealed the presence of four to eight distinct isoforms in EPO-alpha and EPO-beta, while four isoforms, which appeared in the more acidic area of the gels, were detected by immunostaining in NESP. A direct detection of the different N- or O-glycoform pattern from rhEPOs using MALDI-MS was possible by de-sialylation of the glycan structures and after de-N-glycosylation of the intact molecules. Thereby, the

  2. Ionisation of atomic hydrogen by positron impact

    NASA Technical Reports Server (NTRS)

    Spicher, Gottfried; Olsson, Bjorn; Raith, Wilhelm; Sinapius, Guenther; Sperber, Wolfgang

    1990-01-01

    With the crossed beam apparatus the relative impact-ionization cross section of atomic hydrogen by positron impact was measured. A layout of the scattering region is given. The first measurements on the ionization of atomic hydrogen by positron impact are also given.

  3. Single photon ionisation of self assembled monolayers

    NASA Astrophysics Data System (ADS)

    King, B. V.; Savina, M. R.; Tripa, C. E.; Calaway, W. F.; Veryovkin, I. V.; Moore, J. F.; Pellin, M. J.

    2002-05-01

    Self assembled monolayers formed from benzenethiol, diphenylsulphide and diphenyldisulphide have been analysed using secondary ion mass spectrometry (SIMS), sputter neutral mass spectrometry (SNMS) and laser desorption photoionisation mass spectrometry (LDPI). The peak corresponding to the parent ion was much stronger in LDPI than with SIMS or SNMS analysis and fragmentation was lower. A useful yield of order 0.5% was obtained for LDPI from diphenyldisulphide.

  4. Effets de rayonnement sur les detecteurs au silicium a pixels du detecteur ATLAS

    NASA Astrophysics Data System (ADS)

    Lebel, Celine

    Two detection systems are using pixel silicon detectors in the ATLAS detector: the Pixel, which is the subdetector closest to the interaction point, and the MPX network. The activation of the materials present in the Pixel produced by radiation has been measured in two experiments which we performed at CERF (CERN) and NPI-ASCR (Czech Republic). These experimental studies of activation are compared with GEANT4 simulations. The results of these comparisons show that the simulation can predict the activities with a precision of an order of magnitude. They also show that GEANT4 fails to produce certain radioisotopes seen in the experimental activation studies. The contribution to background and the residual doses due to the desintegration of the radioisotopes produced by fast neutrons (category in which falls the expected average neutron energy of 1 MeV in ATLAS) are extrapolated to ATLAS conditions. It is found that this background in the ATLAS Pixel subdetector will be negligible and that the doses are well below safety concerns for detector manipulation during maintenance and repair periods. The radiation field also inflicts damages to the silicon detectors thus reducing their detection efficiency. A modified Hecht model is presented using an electric field description which includes the double junction effect and a small exponential component in areas usually considered without electric field. This model allows the description of the detection efficiency as a function of applied bias voltage and irradiation fluence for several types of silicon detectors irradiated by particles of different types and energies. On top of validating the Hecht model proposed in this thesis, the studies of the radiation damage on silicon detectors has allowed to conclude that the N1EL hypothesis has to be revised (study with different energies). Using the variation with irradiation fluence of the effective doping concentration and of the leakage current, it is shown that silicon detectors with a higher concentration of oxygen have a radiation hardness slightly improved for low-energy protons compared to standard silicon detectors. It is also demonstrated that the radiation hardness of the Mesa detectors is similar to standard detectors for proton and neutron irradiations. The MPX network includes fourteen pixel detectors located in the ATLAS detector and its cavern. Their goal is to perform, within the ATLAS detector and cavern, real-time measurements of the particle flux (type and energy), the doses and the background signal due to neutrons and photons. It will be shown that these detectors can indeed adequately detect several types of particles produced in ATLAS: photons, neutrons and charged particles. Using low-energy photons, the energy calibration of the comparator threshold is done. A phenomenological model is elaborated describing the charge sharing among pixels which appears when a heavy charged particle stops in the detector. Keywords: ATLAS, Pixel, detectors, silicon, radiation, activation, damage, detection efficiency

  5. Transfert de signaux de rythme et synchronisation pour les besoins du VLBI Spatial.

    NASA Astrophysics Data System (ADS)

    Daigne, G.

    Space VLBI, or one of the radiotelescopes placed into orbit, is a further challenge in radio-interferometry, the coordinates of this array element being poorly related to the other ones in a common reference system. The two space VLBI missions being prepared for a launch in 1995 are shortly described. The author shows the crucial role of a bi-directionnal radio link for transferring a very stable time scale to the satellite, and the influence of the propagation medium on the quality of the transfer. A by-product of the two way link is a precise Doppler measurement which will help in the orbit determination prior to processing the observations. The transferred time scale being left with a degree of freedom, this should trigger new investigations towards the search of a canonic formulation for the equation of the interferometric delay, particularly for a very long and linked interferometer.

  6. Transfert d'énergie linéique et radiosensibilité cellulaire

    NASA Astrophysics Data System (ADS)

    Courdi, A.; Pignol, J. P.; Iborra-Brassart, N.; Hérault, J.; Fares, G.; Hachem, A.; Chauvel, P.

    1998-04-01

    The response of human tumour cell lines to in vitro irradiation by high LET particles depends on several factors. For charged particles, there is an increase in radio-sensitivity with LET up to LET values of about 200 KeV/m, then it decreases for higher values. In clinical practice, the increase in the average LET value with depth leads to a continuous increase in relative biological effectiveness (RBE). The probability of particle traversal through the nucleus producing lethal damage is almost 1 for particles with very high LET values such as 7 MeV Ar (LET = 1500 KeV/μm); it is only 0.02 for 400 MeV O ions (LET = 20 KeV/μm). RBE is inversely related with dose, this relation being more marked for cells with small α/beta values after photon irradiation according to the linear-quadratic formula. Particles that are less efficient than photons in terms of average cell death induce heavy individual cell damage, as shown by the yield of multiple micronuclei (MN). With regard to RBE and intrinsic radiosensitivity, recent data using both the clonogenic method and the MN assay indicate that the higher the radioresistance to photon irradiation, the higher the RBE. La réponse des cellules tumorales humaines à l'irradiation in vitro par des particules de TEL élevé dépend de plusieurs facteurs. Pour les particules chargées, la radiosensibilité augmente avec le TEL jusqu'à des valeurs de TEL voisines de 200 KeV/μm, puis diminue pour des valeurs de TEL supérieures. En clinique, l'augmentation du TEL moyen de la particule chargée en profondeur est responsable d'une efficacité biologique relative (EBR) croissante. La probabilité de mortalité de la cellule par une particule traversant le noyau est proche de 1 pour les particules de TEL très élevé comme l'Ar de 7 MeV par nucléon (TEL = 1500 KeV/μm) ; elle n'est que de 0,02 pour les ions d'O de 400 MeV (TEL = 20 KeV/μm). L'EBR est plus élevée pour les petites doses, la relation EBR/dose étant plus marquée dans les cellules ayant un rapport α/beta plus faible après exposition aux photons, selon le modèle linéaire-quadratique. Les particules moins efficaces que les photons en terme de mortalité cellulaire moyenne induisent des dégâts individuels importants, révélés par la production de micronoyaux (MN) multiples. Concernant le lien entre l'EBR et la radio-sensibilité intrinsèque, les données récentes utilisant à la fois la technique des colonies et la méthode des MN, montrent que l'EBR est d'autant plus élevée que les cellules sont radiorésistantes aux photons.

  7. Etude du transfert thermique conjugue dans les cavites rectangulaires en convection naturelle

    NASA Astrophysics Data System (ADS)

    Nouanegue, Herve Frank

    Energy conservation is one of the most important areas of research and development. In parallel and in conjunction with it, developing clean energy technologies using renewable energy sources is similarly an important area to provide a sustainable energy supply. In this way, the quality of life will continue to flourish and at the same time the environment will be protected. For this purpose, devices operating on the principal of passive utilization techniques are used in different applications such as solar collectors, passive cooling and heating of buildings and others. Many of these applications make use of open and/or closed enclosures having different geometries, in which heat transfer by natural convection is used often with conjunction of conduction and surface radiation. To have the best thermal performance of these devices, the understanding of conjugate heat transfer in basic geometries is essential. The aim of this thesis is to study the influence of conduction and radiation heat transfer on natural convection in rectangular enclosures with different geometries and properties. A mathematical model of the system is developed which combines heat transfer by convection, conduction and radiation. A numeric code based on the volume control method is developed to simulate open and close systems with different geometries, in which the conservation equations of mass, momentum and energy are solved using the control volume method and the radiation heat exchange equations are added by calculating radiative heat flux on the emitting surfaces and treating it as a local heat source for the conjugate heat transfer by the three modes. Four specific configurations have been studied. The first one is a closed square inclined cavity containing a massive wall. The second configuration is an open cavity. The last two configurations involve passive cooling and heating systems in which the air circulates in long vertical channels. Numerical results for all the configuration show that radiative heat transfer represents an important part of the total heat transfer for all studied configurations. In the case where surfaces are assumed to be black bodies, this part is at least 25% and can increase up to 97%, i.e. air circulation is enhanced by surface radiative exchange. On the other hand, it is shown that heat exchange by surface radiation makes the surface temperatures more uniform as a result of which natural convection is reduced. As expected, the wall conductance is an important parameter in the conduction heat transfer through the wall and hence in the thermal performance of the massive wall. More specifically for each studied case, the obtained results are the following: (i) the close cavity inclination has a significant effect on the flow field; its effect is enhanced when the heat source is placed in the upper part of the flow domain. (ii) the aspect ratio of the open cavity affects the air circulation but its influence on the heat transfer is less important; (iii) the heat transfer by natural convection increases with the wall conductance for the case of solar chimney, and thus, the ventilating capacity of the channel is enhanced; (iv) the thermal efficiency of the passive system with thermal mass is reduced when the heat exchange by surface radiation is accounted for and the temperature difference between both external vertical boundaries increases.

  8. Improvements in extremity dose assessment for ionising radiation medical applications.

    PubMed

    Ginjaume, M; Pérez, S; Ortega, X

    2007-01-01

    This study aims at testing the INTE ring dosemeter based on MCP-Ns and TLD-100 detectors on users from the field of medical applications, namely radiopharmacists, personnel at a cyclotron facility with corresponding FDG synthesis cells, interventional radiology technologists and radiologists. These users were chosen due to the fact that they have a significantly high risk of exposure to their hands. Following previous results, MCP-Ns TL thin material was used for radiology measurements, whereas TLD-100 was preferred for other applications. The dosemeters were tested to make sure that they were waterproof and that they could be sterilised properly prior to use. Results confirm the need to implement finger dosimetry, mainly for interventional radiologists as finger dose can be >50 times higher than whole-body dose and 3 times higher than wrist dose. PMID:17277325

  9. Non-ionising electromagnetic environments on manned spacecraft.

    PubMed

    Murphy, J R

    1989-08-01

    Future space travellers and settlers will be exposed to a variety of electromagnetic fields (EMFs). Extrinsic sources will include solar and stellar fluxes, planetary fluxes, and supernovae. Intrinsic sources may include fusion and ion engines, EMFs from electrical equipment, radar, lighting, superconduction energy storage systems, magnetic bearings on gyroscopic control and orientation systems, and magnetic rail microprobe launch systems. Communication sources may include radio and microwave frequencies, and laser generating systems. Magnetic fields may also be used for deflection of radiation. There is also a loss of the normal Geomagnetic field (GMF) which includes static, alternating, and time-varying components. This paper reviews exposure limits and the biological effects of EMFs, and evidence for an electromagnetic sense organ and a relationship between man and the Geomagnetic field. PMID:11540234

  10. Non-targeted effects of ionising radiation and radiotherapy.

    PubMed

    Sjostedt, Svetlana; Bezak, Eva

    2010-09-01

    Modern radiobiology is undergoing rapid change due to new discoveries contradicting the target concept which is currently used to predict dose-response relationships. Thus relatively recently discovered radiation-induced bystander effects (RIBEs), that include additional death, mutation and radio-adaptation in non-irradiated cells, change our understanding of the target concept and broadens its boundaries. This can be significant from a radioprotection point of view and also has the potential to reassess radiation damage models currently used in radiotherapy. This article reviews briefly the general concepts of RIBEs such as the proposed underlying mechanisms of signal induction and propagation, experimental approaches and biological end points used to investigate these phenomena. It also summarises several mathematical models currently proposed in an attempt to quantify RIBE. The main emphasis of this article is to review and highlight the potential impact of the bystander phenomena in radiotherapy. PMID:20857259

  11. The biological effects of ionising radiation on Crustaceans: A review.

    PubMed

    Fuller, Neil; Lerebours, Adélaïde; Smith, Jim T; Ford, Alex T

    2015-10-01

    Historic approaches to radiation protection are founded on the conjecture that measures to safeguard humans are adequate to protect non-human organisms. This view is disparate with other toxicants wherein well-developed frameworks exist to minimise exposure of biota. Significant data gaps for many organisms, coupled with high profile nuclear incidents such as Chernobyl and Fukushima, have prompted the re-evaluation of our approach toward environmental radioprotection. Elucidating the impacts of radiation on biota has been identified as priority area for future research within both scientific and regulatory communities. The crustaceans are ubiquitous in aquatic ecosystems, comprising greater than 66,000 species of ecological and commercial importance. This paper aims to assess the available literature of radiation-induced effects within this subphylum and identify knowledge gaps. A literature search was conducted pertaining to radiation effects on four endpoints as stipulated by a number of regulatory bodies: mortality, morbidity, reproduction and mutation. A major finding of this review was the paucity of data regarding the effects of environmentally relevant radiation doses on crustacean biology. Extremely few studies utilising chronic exposure durations or wild populations were found across all four endpoints. The dose levels at which effects occur was found to vary by orders of magnitude thus presenting difficulties in developing phyla-specific benchmark values and reference levels for radioprotection. Based on the limited data, mutation was found to be the most sensitive endpoint of radiation exposure, with mortality the least sensitive. Current phyla-specific dose levels and limits proposed by major regulatory bodies were found to be inadequate to protect species across a range of endpoints including morbidity, mutation and reproduction and examples are discussed within. These findings serve to prioritise areas for future research that will significantly advance understanding of radiation-induced effects in aquatic invertebrates and consequently enhance ability to predict the impacts of radioactive releases on the environment. PMID:26261880

  12. Confocal imaging of ionised calcium in living plant cells.

    PubMed

    Williams, D A; Cody, S H; Gehring, C A; Parish, R W; Harris, P J

    1990-04-01

    Laser-scanning confocal microscopy has been used in conjunction with Fluo-3, a highly fluorescent visible wavelength probe for Ca2+, to visualize Ca2(+)-dynamics in the function of living plant cells. This combination has overcome many of the problems that have limited the use of fluorescence imaging techniques in the study of the role of cations (Ca2+ and H+) in plant cell physiology and enables these processes to be studied in single cells within intact plant tissue preparations. Maize coleoptiles respond to application of ionophores and plant growth hormones with elevations in cytosolic Ca2+ that can be resolved with a high degree of spatial resolution and can be interpreted quantitatively. PMID:2113832

  13. EURADOS strategic research agenda: vision for dosimetry of ionising radiation.

    PubMed

    Rühm, W; Fantuzzi, E; Harrison, R; Schuhmacher, H; Vanhavere, F; Alves, J; Bottollier Depois, J F; Fattibene, P; Knežević, Ž; Lopez, M A; Mayer, S; Miljanić, S; Neumaier, S; Olko, P; Stadtmann, H; Tanner, R; Woda, C

    2016-02-01

    Since autumn 2012, the European Radiation Dosimetry Group (EURADOS) has been developing its Strategic Research Agenda (SRA), which is intended to contribute to the identification of future research needs in radiation dosimetry in Europe. The present article summarises-based on input from EURADOS Working Groups (WGs) and Voting Members-five visions in dosimetry and defines key issues in dosimetry research that are considered important for the next decades. The five visions include scientific developments required towards (a) updated fundamental dose concepts and quantities, (b) improved radiation risk estimates deduced from epidemiological cohorts, (c) efficient dose assessment for radiological emergencies, (d) integrated personalised dosimetry in medical applications and (e) improved radiation protection of workers and the public. The SRA of EURADOS will be used as a guideline for future activities of the EURADOS WGs. A detailed version of the SRA can be downloaded as a EURADOS report from the EURADOS website (www.eurados.org). PMID:25752758

  14. Teaching about Radioactivity and Ionising Radiation: An Alternative Approach.

    ERIC Educational Resources Information Center

    Millar, Robin; And Others

    1990-01-01

    Children's ideas about radiation and radioactivity are reviewed and several common areas of misunderstanding are identified. An approach to teaching the topic at the secondary school level which seeks to specifically address known difficulties is outlined. (CW)

  15. Hand exposure to ionising radiation of nuclear medicine workers.

    PubMed

    Wrzesień, M; Olszewski, J; Jankowski, J

    2008-01-01

    The specific nature of work in nuclear medicine departments involves the use of isotopes and handling procedures, which contribute to the considerable value of an equivalent dose received, in particular, by the fingertips. Standard nuclear medicine department uses ring dosemeters placed usually at the base of the middle finger. The main aim of the study was to find out whether a relationship exists between the doses recorded by thermoluminescent detectors placed at various locations on the radiopharmacists' hands and the doses recorded by the ring detectors, and to determine the character of that relationship. The correction factor represents a correction value to be used to calculate the doses which might be received by locations on the hand from the dose recorded by the ring dosemeter. The dose recorded by the ring dosemeter is on the average five times lower than that received by the fingertips of thumb, index and middle fingers. PMID:18310609

  16. Comparison of precise ionising Radiation Dose Measurements on board Aircraft

    NASA Astrophysics Data System (ADS)

    Lindborg, L.; Beck, P.; Bottollier, J. F.; Roos, H.; Spurny, F.; Wissman, F.

    2003-04-01

    The cosmic radiation makes aircrew one of the most exposed occupational groups. The European Council has therefore in its Directive 96/29Euratom on basic safety standards for radiation protection a particular article (42) for the protection of aircrew. One of the measures to be taken is to assess the exposure of the crew. This is, however, not a trivial task. The radiation consists of many different types of radiation with energies that are hardly met on ground. The knowledge on the dose levels on board aircraft has improved gradually during the last decade as several groups around the world have performed measurements on board civil aircraft in cooperation with airlines. Only occasionally has more than one instrument been able to fly at the same time for practical reasons. The statistical uncertainty in a measurement of the dose equivalent rate is typically ±15 % (1 relative standard deviation) if determined during half an hour. Systematic uncertainties add to this. The dose rate depends on flight altitude, geographic coordinates of the flight, the phase of the solar cycle and the prevailing solar wind. For that reason the possibility to fly on the same flight will eliminate some of the systematic uncertainties that limits an evaluation of the measurement techniques. The proposal aims at measurements on board the aircraft on a geographically limited area for a few hours to decrease the statistical uncertainty of the measurements and thereby get an excellent opportunity to look for possible systematic differences between the different measurement systems. As the dose equivalent rate will be quite well established it will also be possible to compare the measured values with calculated ones. The dose rate increases towards the geomagnetic poles and decreases towards the equator. The composition of the radiation components varies also with altitude. For that reason measurements both at southern latitude and at northern latitude are planned.

  17. Un exemple de transfert de technologie dans le domaine des polymères conducteurs : le projet ``HYRA"

    NASA Astrophysics Data System (ADS)

    Parneix, J. P.; Miane, J. L.; Colin, T.; Ruffie, G.; Mege, J.

    1998-06-01

    The HYRA project is a response to the restructuration of local companies : these are purveyors of high technology military and spatial especially in the radars business. Furthermore, the development of mobile communications needs devices and materials in the millimeter range (from 20 to 100Ghz). The aim of the HYRA project is the development of materials with specific properties - particularly conducting materials - in the millimeter wave range. The results obtained on thermoplastic/conducting polymer composites are presented. Le projet HYRA répond à des préoccupations régionales liées à des restructurations industrielles : les industries régionales fournissant les marchés militaires et spatiaux disposent de techniques très performantes mais coûteuses, en particulier dans le domaine des radars. Par ailleurs le développement des communications mobiles a besoin de dispositifs et de matériaux dans tout le domaine millimétrique (de 20 à 100 Ghz). Le projet HYRA a pour but le développement de matériaux à propriétés spécifiques - en particulier conducteurs - dans ce domaine de fréquence. Les résultats obtenus sur des composites thermoplastiques/polymères conducteurs sont présentés.

  18. Study of photon emission by electron capture during solar nuclei acceleration. 2: Delimitation of conditions for charge transfert establishment

    NASA Technical Reports Server (NTRS)

    Perez-Peraza, J.; Alvarez, M.; Gallegos, A.

    1985-01-01

    The conditions for establishment of charge transfer during acceleration of nuclei up to Fe, for typical conditions of solar flare regions T = 5 x 10 to the 3rd power to 2.5 x 10 to the 8th power degrees K were explored. Results show that such conditions are widely assorted, depending on the acceleration mechanism, the kind of projections and their velocity, the target elements, the source temperature and consequently on the degree of ionization of matter and the local charge state of the accelerated ions. Nevertheless, in spite of that assorted behavior, there are some general tendencies that can be summarized as follows. In atomic H electron capture is systematically established from thermal energies up to high energies, whatever the element and for both acceleration process. For a given element and fixed temperature (T), the probability and energy domain of electron capture and loss with Fermi are higher than with Betatron acceleration. For a given acceleration process the heavier the ion the higher the probability and the wider the energy range for electron capture and loss. For given acceleration mechanism and fixed element the importance and energy domain of capture and loss increase with T: for those reasons, the energy range of charge equilibrium (illustrated with solid lines on the next figs.) is wider with Fermi and increases with temperature and atomic number of projectiles. For the same reasons, electron loss is smaller while the lighter the element, the lower the temperature and the Betatron process, such that there are conditions for which electron loss is not allowed at low energies, but only electron capture is established.

  19. La structure de Jordan des matrices de transfert des modeles de boucles et la relation avec les hamiltoniens XXZ

    NASA Astrophysics Data System (ADS)

    Morin-Duchesne, Alexi

    Lattice models such as percolation, the Ising model and the Potts model are useful for the description of phase transitions in two dimensions. Finding analytical solutions is done by calculating the partition function, which in turn requires finding eigenvalues of transfer matrices. At the critical point, the two dimensional statistical models are invariant under conformal transformations and the construction of rational conformal field theories, as the continuum limit of these lattice models, allows one to compute the partition function at the critical point. Many researchers think however that the paradigm of rational conformal conformal field theories can be extended to include models with non diagonalizable transfer matrices. These models would then be described, in the scaling limit, by logarithmic conformal field theories and the representations of the Virasoro algebra coming into play would be indecomposable. We recall the construction of the double-row transfer matrix DN (λ, u) of the Fortuin-Kasteleyn model, seen as an element of the Temperley-Lieb algebra. This transfer matrix comes into play in physical theories through its representation in link modules (or standard modules). The vector space on which this representation acts decomposes into sectors labelled by a physical parameter d, the number of defects, which remains constant or decreases in the link representations. This thesis is devoted to the identification of the Jordan structure of DN(λ, u) in the link representations. The parameter β = 2 cos λ = -(q + q-1) fixes the theory : for instance β = 1 for percolation and 2 for the Ising model. On the geometry of the strip with open boundary conditions, we show that DN(λ, u) has the same Jordan blocks as its highest Fourier coefficient, FN. We study the non-diagonalizability of FN through the divergences of some of the eigenstates of ρ(F N) that appear at the critical values of λ. The Jordan cells we find in ρ(DN(λ, u)) have rank 2 and couple sectors d and d' when specific constraints on λ, d, d' and N are satisfied. For the model of critical dense polymers (β = 0) on the strip, the eigenvalues of ρ(DN(λ, u)) were known, but their degeneracies only conjectured. By constructing an isomorphism between the link modules on the strip and a subspace of spin modules of the XXZ model at q = i, we prove this conjecture. We also show that the restriction of the Hamiltonian to any sector d is diagonalizable, and that the XX Hamiltonian has rank 2 Jordan cells when N is even. Finally, we study the Jordan structure of the transfer matrix T N(λ, ν) for periodic boundary conditions. When λ = πa/b and a, b ∈ Z× , the matrix TN(λ, ν) has Jordan blocks between sectors, but also within sectors. The approach using FN admits a generalization to the present case and allows us to probe the Jordan cells that tie different sectors. The rank of these cells exceeds 2 in some cases and can grow indefinitely with N. For the Jordan blocks within a sector, we show that the link modules on the cylinder and the XXZ spin modules are isomorphic except for specific curves in the (q, ν) plane. By using the behavior of the transformation ĩd N in a neighborhood of the critical values (qc, ν c), we explicitly build Jordan partners of rank 2 and discuss the existence of Jordan cells with higher rank. Keywords : phase transitions, Ising model, Potts model, Fortuin-Kasteleyn model, transfer matrix method, XXZ Hamiltonian, logarithmic conformal field theory, Jordan structure.

  20. Memorisation et transfert dans l'apprentissage des langues etrangeres (Memorization and Transfer in the Learning of Foreign Languages)

    ERIC Educational Resources Information Center

    Bastin, Georges

    1977-01-01

    Account of an experiment reported in "Bulletin de Psychologie." The results indicate a correlation between practice using a wide variety of semantic elements and better retention and use of correct syntax. This experiment indicates the importance of insuring growth in inductive capacity of learners. (Text is in French.) (AMH)

  1. Electromagnetic processes at low momentum transfer : a review for users

    NASA Astrophysics Data System (ADS)

    Parizet, M. J.; Borie, E.; Grossetête, B.; Isabelle, D. B.; Proriol, J.

    Electromagnetic processes at low momentum transfer are often sources of background in many experiments. To be removed these effects must be calculated by the experimentalist, who must have a good knowledge of the validity of the theoretical formulas that he must use. Then we thought that it will be useful to prepare this review whose presentation is such that it should allow everyone to appreciate the accuracy of formulas that he must use in very complex situations. In this paper, we examine the problem related to bremsstrahlung, pair production and radiative corrections. The first part is devoted to kinematic and to the methods used to establish the corresponding cross sections. Les phénomènes électromagnétiques à faible transfert d'impulsion interviennent dans de nombreuses expériences comme des phénomènes parasites. Pour les éliminer, l'expérimentateur doit les calculer, mais il connait généralement mal la validité des formules théoriques qu'il doit alors utiliser. Il nous a donc paru utile de faire une revue dont la présentation doit permettre à chacun d'apprécier la précision des formules qu'il doit appliquer dans des situations très souvent complexes. Dans cet article, nous faisons le point, tant pour la théorie que pour l'expérience, en ce qui concerne : le rayonnement de freinage, la production de paires et les corrections radiatives. La première partie est consacrée à la cinématique des processus appréciés et aux méthodes permettant d'établir les sections efficaces correspondantes.

  2. Radiation-induced degradation of DNA bases

    NASA Astrophysics Data System (ADS)

    Douki, T.; Delatour, T.; Martini, R.; Cadet, J.

    1999-01-01

    Radio-induced degradation of DNA involves radical processes. A series of lesions among the major bases degradation products has been measured in isolated DNA exposed to gamma radiation in aerated aqueous solution. Degradation can be accounted for by the formation of hydroxyl radicals upon radiolysis of water (indirect effect). The four bases are degraded in high yield. Direct effect has been mimicked by photo-induced electron abstraction from the bases producing their radical cation. Quantification of the modified bases showed that guanine is the preferential target. This can be explained by its lower oxidation potential and charge transfer phenomena. La décomposition radio-induite de l'ADN fait intervenir des processus radicalaires. Une série de lésions choisies parmi les produits majeurs de dégradation des bases a été mesurée dans de l'ADN isolé exposé au rayonnement en solution aqueuse aérée. Les modifications sont alors dues aux radicaux hydroxyles produits par la radiolyse de l'eau (effet indirect) et les quatre bases sont efficacement dégradées. L'arrachement d'électrons aux bases par photosensibilisation pour produire leur radical cation, a été utilisé comme modèle de l'effet direct. La quantification des bases modifiées montre que la guanine est préférentiellement dégradée. Cette observation peut s'expliquer par le plus faible potentiel d'oxydation de cette base ainsi que par les phénomènes de transfert de charge vers les guanines.

  3. Experimental qualification of a code for optimizing gamma irradiation facilities

    NASA Astrophysics Data System (ADS)

    Mosse, D. C.; Leizier, J. J. M.; Keraron, Y.; Lallemant, T. F.; Perdriau, P. D. M.

    Dose computation codes are a prerequisite for the design of gamma irradiation facilities. Code quality is a basic factor in the achievement of sound economic and technical performance by the facility. This paper covers the validation of a code by reference dosimetry experiments. Developed by the "Société Générale pour les Techniques Nouvelles" (SGN), a supplier of irradiation facilities and member of the CEA Group, the code is currently used by that company. (ERHART, KERARON, 1986) Experimental data were obtained under conditions representative of those prevailing in the gamma irradiation of foodstuffs. Irradiation was performed in POSEIDON, a Cobalt 60 cell of ORIS-I. Several Cobalt 60 rods of known activity are arranged in a planar array typical of industrial irradiation facilities. Pallet density is uniform, ranging from 0 (air) to 0.6. Reference dosimetry measurements were performed by the "Laboratoire de Métrologie des Rayonnements Ionisants" (LMRI) of the "Bureau National de Métrologie" (BNM). The procedure is based on the positioning of more than 300 ESR/alanine dosemeters throughout the various target volumes used. The reference quantity was the absorbed dose in water. The code was validated by a comparison of experimental and computed data. It has proved to be an effective tool for the design of facilities meeting the specific requirements applicable to foodstuff irradiation, which are frequently found difficult to meet.

  4. ESR/alanine dosimetry applied to radiation processing

    NASA Astrophysics Data System (ADS)

    Mosse, D. C.

    The radiation processing of food products is specified in terms of absorbed dose, and processing quality is assessed on the basis of absorbed dose measurements. The validity of process quality control is highly dependent on the quality of the measurements and associated instrumentation; in this respect, dosimetry calibration by an Organization with official status provides an essential guarantee of validity to the quality control steps taken. The Laboratoire de Métrologie des Rayonnements Ionisants (L.M.R.I.) is the primary standards and evaluation laboratory approved by the Bureau National de Métrologie (B.N.M.), which is the French National Bureau of Standards. The LMRI implements correlation procedures in response to the various requirements which arise in connection with high doses and doserates. Such procedures are mainly based on ESR/alanine spectrometry, a dosimetry technique ideally suited to that purpose. Dosemeter geometry and design are tailored to operating conditions. "Photon" dosemeters consist of a detector material in powder or compacted form, and a wall with thickness and chemical composition consistent with the application. "Electron" dosemeters have a detector core of compacted alanine with thickness down to a few tenths of a millimeter. The ESR/alanine dosimetry technique, developed at LMRI is a flexible, reliable and accurate tool which effectively meets the various requirements arising in the field of reference dosimetry, where high doses and doserates are involved.

  5. KEY COMPARISON: International key comparison of 24 keV neutron fluence measurements (1993-2009): CCRI(III)-K1

    NASA Astrophysics Data System (ADS)

    Thomas, D. J.; Lewis, V. E.; Klein, H.; Allisy-Roberts, P. J.

    2010-01-01

    A comparison of 24.5 keV neutron fluence standards was organized by Section III (Neutron Measurements) of the Comité Consultatif des Rayonnements Ionisants, (CCRI). The exercise involved the circulation of a set of three different-diameter Bonner spheres for calibration in fields with energies around 24.5 keV. The fields were produced using four different methods of neutron production. The responses (counts per unit neutron fluence) of the individual spheres were initially determined for the neutron energy of the production method, or methods, employed. To derive the 24.5 keV responses, it was necessary to make corrections for spectral effects, and these were achieved by using response functions for the spheres calculated using the code MCNP. The results demonstrate good consistency within the estimated uncertainties (ranging from about 5% to 10% at the 95% confidence level) between the results reported by all the participants. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI Section III, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

  6. Dysfonctionnements radio-induits du transport colique chez le rat

    NASA Astrophysics Data System (ADS)

    François, A.; Lebrun, F.; Ksas, B.; Aigueperse, J.; Gourmelon, P.; MacNaughton, W. K.; Griffiths, N. M.

    1998-04-01

    The symptom commonly associated with whole body irradiation is diarrhoea, a still quite obscure phenomenon, which leads to decreased chance of cure of irradiated people. The aim of this study was to provide evidence for dysfunction of intestinal water and electrolyte transport regulation by the enteric nervous system after exposure to ionising radiation. This study shows decreased capacity of enteric nervous system to influence colonic transport 3days after irradiation, correlated to a diminished response to a neurotransmitter: serotonin. Radio-induced diarrhea may result from epithelial structural injury but also from impaired regulatory processes of intestinal transport. L'un des symptômes majeurs d'une irradiation corporelle totale ou abdominale est l'apparition de diarrhées, dont les causes sont encore mal connues, et qui mettent en jeu le pronostique vital de l'individu irradié. Cette étude vise à mettre en évidence l'atteinte de la régulation du transport intestinal d'eau et d'électrolytes par les rayonnements ionisants. On observe une diminution de la capacité du système nerveux entérique à influencer le transport colique 3jours après irradiation, corrélée à une diminution de la réponse épithéliale à un neurotransmetteur : la sérotonine. Les diarrhées radio-induites résulteraient d'une atteinte structurelle de l'épithélium mais également des processus de régulation du transport intestinal.

  7. Search for variability in the kinematics of the ionised circumstellar region of M2-9

    NASA Astrophysics Data System (ADS)

    Torres-Peimbert, S.; Arrieta, A.; Georgiev, L.

    In our previous study of M2-9 we found that the radial velocities of the forbidden lines of the ionized species in the nuclear spectra show a negative gradient which correlates with density, electron temperature and electron pressure. The size of the ionized region is relatively small and the travel time with the observed velocities is of order of decades. In an attempt to reveal the nature of the unusual velocity gradient, we present second epoch observational spectral data of the nucleus of M2-9.

  8. Inter-comparison of safety culture within selected practices in Ghana utilising ionising radiation.

    PubMed

    Faanu, A; Schandorf, C; Darko, E O; Boadu, M; Emi-Reynolds, G; Awudu, A R; Gyekye, P K; Kpeglo, D O

    2010-12-01

    The safety culture of selected practices and facilities in Ghana utilising radiation sources or radiation emitting devices has been assessed using a performance indicator, which provided status information on management and operating staff commitment to safety. The questionnaire was based on the following broad areas: general safety considerations, safety policy at the facility level, safety practices at the facility level, definition of responsibility, staff training, safety of the physical structure of the facility and the emergency plans. The analysis showed that the percentage levels of commitment to safety for the respective practices are as follows: conventional radiography, 23.3-90.0%; research reactor, 73.3%; gamma irradiation facility, 53.3%; radiotherapy, 76.7%; X-ray scanner, 80.0%; gamma scanner, 76.7%; industrial radiography 86.7% and nuclear density practice, 78%. None of the practices or facilities was able to satisfy all the requirements that will ensure a 100% level of safety culture. PMID:20699247

  9. Modelling chromosomal aberration induction by ionising radiation: The influence of interphase chromosome architecture

    NASA Astrophysics Data System (ADS)

    Ottolenghi, A.; Ballarini, F.; Biaggi, M.

    Several advances have been achieved in the knowledge of nuclear architecture and functions during the last decade, thus allowing the identification of interphase chromosome territories and sub-chromosomal domains (e.g. arm and band domains). This is an important step in the study of radiation-induced chromosome aberrations; indeed, the coupling between track-structure simulations and reliable descriptions of the geometrical properties of the target is one of the main tasks in modelling aberration induction by radiation, since it allows one to clarify the role of the initial positioning of two DNA lesions in determining their interaction probability. In the present paper, the main recent findings on nuclear and chromosomal architecture are summarised. A few examples of models based on different descriptions of interphase chromosome organisation (random-walk models, domain models and static models) are presented, focussing on how the approach adopted in modelling the target nuclei and chromosomes can influence the simulation of chromosomal aberration yields. Each model is discussed by taking into account available experimental data on chromosome aberration induction and/or interphase chromatin organisation. Preliminary results from a mechanistic model based on a coupling between radiation track-structure features and explicitly-modelled, non-overlapping chromosome territories are presented.

  10. Measurements of Quantum-Electrodynamic Effects in Highly-Ionised Atoms

    NASA Astrophysics Data System (ADS)

    Lea, Stephen Nicholas

    Available from UMI in association with The British Library. Requires signed TDF. The 2^2S_ {1/2} - 2^2 P_{3/2} transition in the hydrogen-like silicon ion Si^{13+ } is observed by intra-cavity cw laser resonance spectroscopy of a fast silicon ion beam. The observed wavelength is consistent with a theoretical value of 734.03(2) nm. This experiment constitutes the first observation of a Lamb shift in this ion and the first intra-cavity cw laser resonance spectroscopy of highly charged ions. Precision measurements of this interval in ions of similar atomic number display a small discrepancy with theory and hence this transition is of current theoretical and experimental interest. This observation represents a stage in the development of a technique which may lead to more precise measurements of this interval. Resonance of the laser wavelength with the transition is detected by monitoring the Lyman-alpha X-ray decay of the stimulated 2^2 P state population. A five standard deviation resonance is observed from 16.6 mC of ion beam, at laser wavelengths within a natural linewidth of the theoretical transition wavelength. The reproducibility of the resonance data is limited by systematic effects arising from small changes in the ion and laser beam overlap geometry.

  11. Tautomeric and ionisation forms of dopamine and tyramine in the solid state

    NASA Astrophysics Data System (ADS)

    Cruickshank, Laura; Kennedy, Alan R.; Shankland, Norman

    2013-11-01

    Crystallisation of the phenylethylamine neurotransmitter dopamine from basic aqueous solution yielded the 3-phenoxide Zwitterionic tautomer, despite this being a minority form in the solution state. In the crystal structure, dopamine has a dimeric [OCCOH]2 hydrogen bonded catechol motif that expands through Nsbnd H⋯O interactions to give a 2-dimensional sheet of classical hydrogen bonds. These sheets are further interconnected by Nsbnd H⋯π interactions. The structurally related base tyramine crystallises under similar conditions as a hemihydrate with all four possible species of tyramine present (cationic, anionic, Zwitterionic and neutral) in the crystal structure. Single crystal X-ray diffraction studies at 121 and 293 K showed dynamic hydrogen atom disorder for the phenol/phenoxide group, suggesting that the tyramine speciation observed arises from a solid-state process.

  12. Theoretical survey on positronium formation and ionisation in positron atom scattering

    NASA Technical Reports Server (NTRS)

    Basu, Madhumita; Ghosh, A. S.

    1990-01-01

    The recent theoretical studies are surveyed and reported on the formation of exotic atoms in positron-hydrogen, positron-helium and positron-lithium scattering specially at intermediate energy region. The ionizations of these targets by positron impact was also considered. Theoretical predictions for both the processes are compared with existing measured values.

  13. Pre-service Teachers' Subject Knowledge of and Attitudes about Radioactivity and Ionising Radiation

    NASA Astrophysics Data System (ADS)

    Denys Colclough, Nicholas; Lock, Roger; Soares, Allan

    2011-02-01

    This study focussed on secondary school (11-18 years) pre-service teachers' (n = 73) knowledge of and attitudes towards risks associated with alpha, beta, and gamma radiations. A multi-method approach was used with physics, chemistry, biology, and history graduates undertaking the one-year initial teacher training, Post Graduate Certificate in Education course at a university in central England. A novel research tool, involving interviews about real concrete contexts and first-hand data collection with radioactive sources, was employed to gain insights into a sub-set of the sample (n = 12) of pre-service teachers' subject knowledge of and attitudes towards risk. The subject knowledge of all the pre-service teachers was also measured using a Certainty of Response Index instrument; multiple-choice questions with associated confidence indicators. Although the physicists displayed the higher levels of knowledge, they also demonstrated limitations in their knowledge and held misconceptions such as irradiation being confused with contamination. Physics graduates hold more rational attitudes and a greater willingness to accept risk while the attitudes of graduates in the other subject disciplines are more disparate. These findings raise questions about the extent to which pre-service science and history teachers have the knowledge necessary to teach this topic. The article concludes with discussion of the implications these findings have for initial teacher training, continuing professional development needs for teachers already in the profession, and curriculum developers.

  14. Chromosome instability of HPRT-mutant subclones induced by ionising radiation of various LET.

    PubMed

    Govorun, R D; Koshlan, I V; Koshlan, N A; Krasavin, E A; Shmakova, N L

    2002-01-01

    The induction of HPRT-mutations and survival of Chinese hamster cells (line B11ii-FAF28, clone 431) were studied after irradiation by 4He and 12C-ions of various LET (20-360 keV/micrometers), produced by the U-200 heavy ion accelerator. The RBE increases with LET up to the maximum at 100-200 keV/micrometers and then decreases. Cytogenetic analysis was performed on the HPRT-mutant subclones selected from unirradiated Chinese hamster V-79 cells and from HPRT-mutant subclones that arose after exposure to gamma-rays, 1 GeV protons and 14N-ions (LET-77 keV/micrometers), produced by the synchrophasotron and the U-400M heavy ion accelerator. Slow growing mutant subclones were observed. The cytogenetic properties of individual clones were highly heterogeneous and chromosome instability was observed in both spontaneous and radiation-induced mutants. Chromosome instability was highest among spontaneous mutants and decreased with increasing LET. PMID:12539752

  15. Follow-up of children exposed to ionising radiation from cardiac catheterisation: the Coccinelle study.

    PubMed

    Baysson, H; Nkoumazok, B; Barnaoui, S; Réhel, J L; Girodon, B; Milani, G; Boudjemline, Y; Bonnet, D; Laurier, D; Bernier, M O

    2015-07-01

    Cardiac catheterisation has become an essential tool in the diagnosis and treatment of children with a wide variety of congenital and acquired forms of cardiovascular disease. Despite the clear clinical benefit to the patient, radiation exposure from paediatric cardiac catheterisation procedures (CCPs) may be substantial. Given children's greater sensitivity to radiation and the longer life span during which radiation health effects can develop, an epidemiological cohort study, named Coccinelle or 'Ladybird' (French acronym for 'Cohorte sur le risque de cancer après cardiologie interventionnelle pédiatrique'), is carried out in France to evaluate the risks of leukaemia and solid cancers in this population. A total number of 8000 included children are expected. Individual CCP-related doses will be assessed for each child included in the cohort. For each CCP performed, dosimetric parameters (dose-area product, fluoroscopy time and total number of cine frames) are retrieved retrospectively. Organ doses, especially to the lung, the oesophagus and the thyroid, are calculated with PCXMC software. The cohort will be followed up through linkage with French paediatric cancer registries. PMID:25833897

  16. Measurement of occupational doses of ionising radiation to the lens of the eyes of interventional radiologists.

    PubMed

    Higgins, Anthony

    2016-03-01

    Currently, there exists no standardised method for monitoring radiation doses to the eye lens. This investigation aimed to determine the optimum method for monitoring the eye doses for interventional radiologists. Three interventional radiologists were issued with a series of dosimeters to wear during their routine work. These dosimeters were worn at defined positions on the body and the absorbed dose to each position was measured. It was confirmed that the dose received to the thyroid collar followed an apparently well-defined relationship to the dose recorded on the forehead, which is representative of the dose to the lens of the eye. It was also confirmed that, as hypothesised, the dose to the left eye was universally greater than to the right, although by varying factors. It was concluded that the use of dosimeters attached to the inside arms of protective eyewear is the optimum solution for eye lens dosimetry. It was also concluded that, when used with a dose conversion factor which corroborates existing literature, dosimeters attached to the outside of a thyroid collar yield sufficiently accurate results for use in routine dosimetry programmes. PMID:26643204

  17. Herschel/HIFI observations of ionised carbon in the β Pictoris debris disk

    NASA Astrophysics Data System (ADS)

    Cataldi, G.; Brandeker, A.; Olofsson, G.; Larsson, B.; Liseau, R.; Blommaert, J.; Fridlund, M.; Ivison, R.; Pantin, E.; Sibthorpe, B.; Vandenbussche, B.; Wu, Y.

    2014-03-01

    Context. The dusty debris disk around the ~20 Myr old main-sequence A-star β Pictoris is known to contain gas. Evidence points towards a secondary origin of the gas as opposed to being a direct remnant from the initial protoplanetary disk, although the dominant gas production mechanism is so far not identified. The origin of the observed overabundance of C and O compared with solar abundances of metallic elements such as Na and Fe is also unclear. Aims: Our goal is to constrain the spatial distribution of C in the disk, and thereby the gas origin and its abundance pattern. Methods: We used the HIFI instrument on board the Herschel Space Observatory to observe and spectrally resolve C ii emission at 158 μm from the β Pic debris disk. Assuming a disk in Keplerian rotation and a model for the line emission from the disk, we used the spectrally resolved line profile to constrain the spatial distribution of the gas. Results: We detect the C ii 158 μm emission. Modelling the shape of the emission line shows that most of the gas is located at about ~100 AU or beyond. We estimate a total C gas mass of 1.3-0.5+1.3 × 10-2 M⊕ (central 90% confidence interval). The data suggest that more gas is located on the south-west side of the disk than on the north-east side. The shape of the emission line is consistent with the hypothesis of a well mixed gas (constant C/Fe ratio throughout the disk). Assuming instead a spatial profile expected from a simplified accretion disk model, we found it to give a significantly poorer fit to the observations. Conclusions: Since the bulk of the gas is found outside 30 AU, we argue that the cometary objects known as "falling evaporating bodies" are probably not the dominant source of gas; production from grain-grain collisions or photodesorption seems more likely. The incompatibility of the observations with a simplified accretion disk model might favour a preferential depletion explanation for the overabundance of C and O, although it is unclear how much this conclusion is affected by the simplifications made. More stringent constraints on the spatial distribution will be available from ALMA observations of C i emission at 609 μm. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  18. Follow-up of children exposed to ionising radiation from cardiac catheterisation: the Coccinelle study

    PubMed Central

    Baysson, H.; Nkoumazok, B.; Barnaoui, S.; Réhel, J. L.; Girodon, B.; Milani, G.; Boudjemline, Y.; Bonnet, D.; Laurier, D.; Bernier, M. O.

    2015-01-01

    Cardiac catheterisation has become an essential tool in the diagnosis and treatment of children with a wide variety of congenital and acquired forms of cardiovascular disease. Despite the clear clinical benefit to the patient, radiation exposure from paediatric cardiac catheterisation procedures (CCPs) may be substantial. Given children's greater sensitivity to radiation and the longer life span during which radiation health effects can develop, an epidemiological cohort study, named Coccinelle or ‘Ladybird’ (French acronym for ‘Cohorte sur le risque de cancer après cardiologie interventionnelle pédiatrique’), is carried out in France to evaluate the risks of leukaemia and solid cancers in this population. A total number of 8000 included children are expected. Individual CCP-related doses will be assessed for each child included in the cohort. For each CCP performed, dosimetric parameters (dose–area product, fluoroscopy time and total number of cine frames) are retrieved retrospectively. Organ doses, especially to the lung, the oesophagus and the thyroid, are calculated with PCXMC software. The cohort will be followed up through linkage with French paediatric cancer registries. PMID:25833897

  19. Up-Dating Of Atomic Data Needed For Ionisation Balance Evaluations of Krypton and Molybdenum

    SciTech Connect

    Mattioli, M; Mazzitelli, G; Fournier, K B; Finkenthal, M; Carraro, L

    2006-06-01

    Atomic data for both ionization and recombination of Kr and Mo ions are reviewed, since the rate coefficients for these processes need to be regularly up-dated following the publication of new theoretical calculations and new experimental data. Kr is used in magnetic-confinement-fusion devices to produce a peripheral radiating mantle meant to spread the heat confinement-load on the plasma-facing components. In a few tokamaks Mo tiles cover the plasma-facing surfaces, acting in most cases as a plasma-column limiter. The collected atomic data represent the state of the art on the ionization and recombination data for the two considered elements. Samples of rates are proposed for both ionization and recombination along with tables of the fractional abundances at ionization equilibrium. The proposed rates should be included in codes that simulate the impurity behavior in magnetic-confinement-fusion devices, i.e., when radial transport is added to ionization and recombination to predict spatially resolved charge-state distributions that are to be compared with experimental results.

  20. Determination of methemoglobin in human blood after ionising radiation by EPR

    NASA Astrophysics Data System (ADS)

    Polakovs, M.; Mironova-Ulmane, N.; Pavlenko, A.; Aboltins, A.

    2015-03-01

    In the present work presents results of investigations of radiation influence on blood of patients examined by radio-isotopes diagnosis (Tc99m), blood of Chernobyl clean-up workers and human blood irradiated by LINAC using Electron Paramagnetic Resonance (EPR). The EPR spectroscopy reveals information on electronic states of transition metal ions, particularly Fe3+ in different spin states. It is shown that EPR spectra of blood of patients before examination has signal from metal-protein transferrin (g=4.3) and after administration of radioisotope proves signal of Fe3+ (methemaglobin) in the high spin state (g=6.0). The EPR spectra of Chernobyl liquidator display number of signals including low and high state of ion Fe3+ (g = 2.0 and g=6.0), and transferrin (g=4.3). The EPR spectra of irradiated human blood by LINAC (linear accelerator) have only signal Fe3+ (methemaglobin) in low-spin state with g = 2.0.

  1. Deterministic effect of lens at leukergy of patients who received low doses of ionising radiation.

    PubMed

    Yeltokova, M; Zharliganova, D; Shaidarov, M; Bakhtin, M; Kazymbet, P; Tel, L; Dossakhanov, A; Kozhakbayeva, M; Hoshi, M

    2015-09-01

    To explore the possibility to use the lens extract as an in vitro stimulator to conduct a test of stimulated leukergy in liquidators of the accident consequences (LAC) on Chernobyl Nuclear Power Plant (CNPP) with a cataract in the long-term period. The study sample included 72 men-LAC on CNPP, at the age from 42 to 65 y, who have a cataract. The comparison group consisted of 60 men, with a cataract, of the same age, and who were not exposed to radiation. The control group was composed of 60 men, at the age of 42-58 y without lens pathology. Phenomenon of the stimulated leukergy was revealed in persons who had been exposed to radiation in the dose of 18.2 ± 0.58 cGy and was observed in 5.7-8.05 % (P < 0.001), suggesting a continued high auto-aggression to the lens antigens, and the strength of cell-mediated immunity. PMID:25969524

  2. Implications of the observations of partially ionised states in the low energy galactic cosmic rays

    NASA Technical Reports Server (NTRS)

    Mitra, Banashree; Biswas, S.; Durgaprasad, N.; Dutta, A.; Goswami, J. N.; Ramadurai, S.

    1991-01-01

    Of the low energy (30-100 MeV/N)Fe-group nuclei of Galactic cosmic rays (GCRs) a fraction of about 20 percent of these are in partially ionized states. The origin of these particles are not known at present. From the considerations of relevant cross-sections, the following two important processes of the phenomena are given: (1) these GCR Fe-group nuclei must have captured the orbital electrons at energies of 1-5 MeV/N, while traversing matter; and (2) that these GCR ions of 1-5 MeV/N are then reaccelerated to energies of at least 30-100 MeV/N, most probably in the heliospheric boundary region. Three possible scenarios of the electron-capture processes are briefly discussed: (1) electron capture in a large molecular cloud; (2) GCR equilibrium spectra in ISM and their equilibrium charge; and (3) electron capture in the Oort's cloud.

  3. Non-fluoroscopic navigation systems for radiofrequency catheter ablation for supraventricular tachycardia reduce ionising radiation exposure

    PubMed Central

    See, Jason; Amora, Jonah L; Lee, Sheldon; Lim, Paul; Teo, Wee Siong; Tan, Boon Yew; Ho, Kah Leng; Lee, Chee Wan; Ching, Chi Keong

    2016-01-01

    INTRODUCTION The use of non-fluoroscopic systems (NFS) to guide radiofrequency catheter ablation (RFCA) for the treatment of supraventricular tachycardia (SVT) is associated with lower radiation exposure. This study aimed to determine if NFS reduces fluoroscopy time, radiation dose and procedure time. METHODS We prospectively enrolled patients undergoing RFCA for SVT. NFS included EnSite™ NavX™ or CARTO® mapping. We compared procedure and fluoroscopy times, and radiation exposure between NFS and conventional fluoroscopy (CF) cohorts. Procedural success, complications and one-year success rates were reported. RESULTS A total of 200 patients over 27 months were included and RFCA was guided by NFS for 79 patients; those with atrioventricular nodal reentrant tachycardia (AVNRT), left-sided atrioventricular reentrant tachycardia (AVRT) and right-sided AVRT were included (n = 101, 63 and 36, respectively). Fluoroscopy times were significantly lower with NFS than with CF (10.8 ± 11.1 minutes vs. 32.0 ± 27.5 minutes; p < 0.001). The mean fluoroscopic dose area product was also significantly reduced with NFS (NSF: 5,382 ± 5,768 mGy*cm2 vs. CF: 21,070 ± 23,311 mGy*cm2; p < 0.001); for all SVT subtypes. There was no significant reduction in procedure time, except for left-sided AVRT ablation (NFS: 79.2 minutes vs. CF: 116.4 minutes; p = 0.001). Procedural success rates were comparable (NFS: 97.5% vs. CF: 98.3%) and at one-year follow-up, there was no significant difference in the recurrence rates (NFS: 5.2% vs. CF: 4.2%). No clinically significant complications were observed in both groups. CONCLUSION The use of NFS for RFCA for SVT is safe, with significantly reduced radiation dose and fluoroscopy time. PMID:26805664

  4. Hydromagnetic wave excitation by ionised interstellar hydrogen and helium in the solar wind

    NASA Technical Reports Server (NTRS)

    Lee, Martin A.; Ip, W.-H.

    1987-01-01

    The modification of the interplanetary MHD wave spectrum due to the pickup and isotropization of interstellar hydrogen and helium in the solar wind is predicted on the basis of quasi-linear and (for hydrogen) WKB theory. Results indicate that pickup helium has a very small (unobservable) effect on the solar wind wave spectrum, but that pickup hydrogen results in substantial modifications of cyclotron resonant frequencies (about 0.01 Hz at about 7 AU). It is noted that the predicted modifications beyond about 5 AU are substantial and could be observable at spacecraft frequencies greater than about 0.005 Hz if not degraded by turbulent wave-wave interactions or stochastic ion acceleration.

  5. Population exposure to ionising radiation from CT examinations in Aosta Valley between 2001 and 2008

    PubMed Central

    Catuzzo, P; Aimonetto, S; Zenone, F; Fanelli, G; Marchisio, P; Meloni, T; Pasquino, M; Tofani, S

    2010-01-01

    Recent and continuous advances in CT, such as the development of multislice CT, have promoted a rapid increase in its clinical application. Today, CT accounts for approximately 10% of the total number of medical radiographic procedures worldwide. However, the growing performance of the new CT generations have increased not only the diagnostic opportunities, but also the radiation dose to the patient. The relative contribution to the collective radiation dose is now estimated to be approximately 50%. Several papers have been published concerning the intensive use of CT and its contribution to the collective dose. However, most of the literature concerns the years 1997–2003 and the dosimetric evaluations are generally limited to the main standard protocols (chest, head and abdomen), deriving the effective dose by the simple application of the diagnostic reference levels. Only specific dosimetric analyses of single and innovative procedures have been published recently. Moreover, few data comes from Italian radiology departments. This paper aims to bridge these gaps. Firstly, it characterises in terms of measured CT dose index (CTDI) two last-generation scanners of the Radiological Department of Aosta Hospital. Secondly, it evaluates the effective dose from most of the CT examinations performed from 2001 to 2008 to compare protocols and technologies in line with the suggestions of the 2007 Recommendations of the International Commission on Radiological Protection, Publication 103. Finally, it estimates the collective dose to the population. PMID:21088089

  6. VizieR Online Data Catalog: Ionised gas images of NGC 4569 (Boselli+, 2016)

    NASA Astrophysics Data System (ADS)

    Boselli, A.; Cuillandre, J. C.; Fossati, M.; Boissier, S.; Bomans, D.; Consolandi, G.; Anselmi, G.; Cortese, L.; Cote, P.; Durrell, P.; Ferrarese, L.; Fumagalli, M.; Gavazzi, G.; Gwyn, S.; Hensler, G.; Sun, M.; Toloba, E.

    2016-01-01

    Narrow-band imaging observations were carried out in May 2015 using MegaCam at the CFHT. The galaxy NGC 4569, which has a recessional velocity of -221km/s, was observed in the narrow-band filter MP9603 that was centered on the Hα line (λ= 6590Å; Δλ= 104Å, T=93%). Long-slit spectroscopy observations were carried out in 2001 with the Calar Alto 3.5m telescope using the Twin spectrograph. Its was observed with the T05 and T06 gratings in the blue (4430Å) and red (6562Å) arm of the spectrograph with a dispersion of 36Å/mm and a spatial sampling of 0.56-arcsec/pixel. (2 data files).

  7. Efficient ionisation of calcium, strontium and barium by resonant laser pumping

    NASA Technical Reports Server (NTRS)

    Skinner, C. H.

    1980-01-01

    Efficient ionization has been observed when an atomic vapor of strontium, barium or calcium was illuminated with a long pulse tunable laser at the frequency of the atomic resonance line. The variation in the degree of ionization with neutral density and laser intensity has been measured using the 'hook' method. The maximum ionization observed was 94%. Excited state populations were measured yielding an excitation temperature (depending on exact experimental conditions) in the region of 0.4 eV. The decay of ion density after the laser pulse was monitored and the recombination coefficients determined. The results are interpreted in terms of an electron heating model.

  8. Genotoxicity Induced by Foetal and Infant Exposure to Magnetic Fields and Modulation of Ionising Radiation Effects

    PubMed Central

    Udroiu, Ion; Antoccia, Antonio; Tanzarella, Caterina; Giuliani, Livio; Pacchierotti, Francesca; Cordelli, Eugenia; Eleuteri, Patrizia; Villani, Paola; Sgura, Antonella

    2015-01-01

    Background Few studies have investigated the toxicity and genotoxicity of extremely low frequency magnetic fields (ELF-MF) during prenatal and neonatal development. These phases of life are characterized by cell proliferation and differentiation, which might make them sensitive to environmental stressors. Although in vitro evidences suggest that ELF-MF may modify the effects of ionizing radiation, no research has been conducted so far in vivo on the genotoxic effects of ELF-MF combined with X-rays. Aim and methods Aim of this study was to investigate in somatic and germ cells the effects of chronic ELF-MF exposure from mid gestation until weaning, and any possible modulation produced by ELF-MF exposure on ionizing radiation-induced damage. Mice were exposed to 50 Hz, 65 μT magnetic field, 24 hours/day, for a total of 30 days, starting from 12 days post-conception. Another group was irradiated with 1 Gy X-rays immediately before ELF-MF exposure, other groups were only X-irradiated or sham-exposed. Micronucleus test on blood erythrocytes was performed at multiple times from 1 to 140 days after birth. Additionally, 42 days after birth, genotoxic and cytotoxic effects on male germ cells were assessed by comet assay and flow cytometric analysis. Results ELF-MF exposure had no teratogenic effect and did not affect survival, growth and development. The micronucleus test indicated that ELF-MF induced a slight genotoxic damage only after the maximum exposure time and that this effect faded away in the months following the end of exposure. ELF-MF had no effects on ionizing radiation (IR)-induced genotoxicity in erythrocytes. Differently, ELF–MF appeared to modulate the response of male germ cells to X-rays with an impact on proliferation/differentiation processes. These results point to the importance of tissue specificity and development on the impact of ELF-MF on the early stages of life and indicate the need of further research on the molecular mechanisms underlying ELF-MF biological effects. PMID:26559811

  9. Ionisation from the 3s sub-level of highly charged ions

    NASA Technical Reports Server (NTRS)

    Golden, L. B.; Sampson, D. H.; Omidvar, K.

    1978-01-01

    Scaled electron-impact cross sections are calculated for ionization from the 3s sublevel of hydrogenic ions with Z equal infinity by use of the Born exchange or the Coulomb-Born Oppenheimer approximation (which is exact, apart from relativistic corrections, in this limit). The results are fitted to an analytic expression which goes into the correct Bethe approximation result at high energies and which can readily be integrated over a Maxwellian electron velocity distribution to obtain collision rates. These results permit calculation of the approximate cross section and collision rate for ionization from the 3s sublevel of any highly charged ion with Z/N larger than approximately 2. Results obtained by the described procedure for Fe-14(+) and Fe-15(+) are compared with results obtained by other procedures.

  10. Measurement Of Ultrafast Ionisation From Intense Laser Interactions With Gas-Jets

    SciTech Connect

    Gizzi, Leonida A.; Galimberti, Marco; Giulietti, Antonio; Giulietti, Danilo; Koester, Petra; Labate, Luca; Tomassini, Paolo; Martin, Philippe; Ceccotti, Tiberio; De Oliveira, Pascal; Monot, Pascal

    2006-04-07

    Interaction of an intense, ultrashort laser pulse with a gas-jet target is investigated through femtosecond optical interferometry to study the dynamics of ionization of the gas. Experimental results are presented in which the propagation of the pulse in the gas and the consequent plasma formation is followed step by step with high temporal and spatial resolution. We demonstrate that, combining the phase shift with the measurable depletion of fringe visibility associated with the transient change of refractive index in the ionizing region and taking into account probe travel time can provide direct information on gas ionization dynamics.

  11. Considerations concerning the use of counting active personal dosimeters in pulsed fields of ionising radiation.

    PubMed

    Ambrosi, Peter; Borowski, Markus; Iwatschenko, Michael

    2010-06-01

    Active personal electronic dosimeters (APDs) exhibit limitations in pulsed radiation fields, which cannot be overcome without the use of new detection technology. As an interim solution, this paper proposes a method by which some conventional dosimeters can be operated in a way such that, based on the basic knowledge about the pulsed radiation field, any dosimetric failure of the dosimeter is signalised by the instrument itself. This method is not applicable to all combinations of APD and pulsed radiation field. The necessary requirements for the APD and for the parameters of the pulsed radiation field are given in the paper. Up to now, all such requirements for APDs have not been tested or verified in a type test. The suitability of the method is verified for the use of one APD used in two clinical pulsed fields. PMID:20083488

  12. A radiotelemetry pill for the measurement of ionising radiation using a mercuric iodide detector.

    PubMed

    Hassan, M A; Pearce, G; Edwards, J P

    1978-03-01

    A small radiation measuring pill is briefly described which utilises the principles of radiotelemetry and the properties of a room temperature semiconductor radiation detector such as mercuric iodide. By transmitting a radio signal to a remote receiver the pill could be an effective tool in localising bleeding sites along the gastrointestinal tract and also possibly in the diagnosis of gastrointestinal carcinoma. Other uses of the radiopill are suggested. The size of the pill is 27 mm x 10 mm diameter and consists of a mercuric iodide crystal, an amplifier, a frequency modulated transmitter and one battery. The radiotransmitter operates at about 106 MHz and has a range of about 10m, and the sensitivity of the pill has been found for 99Tcm, 131I and 32P. PMID:306112

  13. Protection against ionising radiation and synergism with thiols by zinc aspartate.

    PubMed

    Floersheim, G L; Floersheim, P

    1986-06-01

    Pre-treatment with zinc aspartate protected mice against the lethal effects of radiation and raised the LD50 from 8 Gy to 12.2 Gy. Zinc chloride and zinc sulphate were clearly less active. The radioprotective effect of zinc aspartate was equivalent to cysteamine and slightly inferior to S,2-aminoethylisothiourea (AET). Zinc aspartate displayed a similar therapeutic index to the thiols but could be applied at an earlier time before irradiation. Synergistic effects occurred with the combined administration of zinc aspartate and thiols. By giving zinc aspartate with cysteamine, the LD50 was increased to 13.25 Gy and, by combining it in the optimal protocol with AET, to 17.3 Gy. The radioprotection by zinc and its synergism with thiols is explained by the stabilisation of thiols through the formation of zinc complexes. PMID:3518853

  14. Analysis of minor and trace elements in gallstones by induction of characteristic ionising radiation.

    PubMed

    Al-Kinani, A T; Harris, I A; Watt, D E

    1984-02-01

    In an investigation of the role of trace elements in gallstone formation and of minor and trace elements in gallstone and bile, samples from five patients were analysed using three different techniques for cross-verification: NAA, PIXE, and XRF. In addition, certified standards of bovine liver and oyster tissue from the NBS, Washington, were re-analysed using the different techniques to confirm the accuracy of the experimental procedures. NAA of five gallstones was used for the quantitative analysis of 19 elements with Z greater than 11. The concentrations of Cl, K + Ca, Mn, Fe and Cu + Zn were determined by PIXE and those of Mg, P, S, K and Ca by XRF. In most cases the concentrations were in the range of a few PPB to a few hundred PPM. The spatial distribution of the component elements was obtained using XRF with a scanning electron microscope and the results demonstrated that calcium was present centrally in all the stones. The analysis of gallbladder bile from four patients showed that the calcium concentration was much greater than normal, indicating that calcium and other elements play an important role in stone formation. Infrared spectroscopy showed that the calcium salts were present in gallstones in three compound forms: calcium carbonate, calcium phosphate and calcium bilirubinate. Reasons for the cause of calcium precipitation are discussed. PMID:6701197

  15. On the mechanism of populating 3p levels of neon under pumping by a hard ioniser

    SciTech Connect

    Khasenov, M U

    2011-03-31

    The effect of quenching additives on the luminescence properties of helium - neon mixtures under pumping by {alpha} particles emitted from {sup 210}Po atoms is considered. It is concluded that, under excitation by a heavy charged particle, the population of the 3p'[1/2]{sub 0} level of neon is not related to the dissociative recombination of molecular ions. It is suggested that the most likely channels for populating the 3p level are the excitation transfer from metastable helium atoms to neon atoms and direct excitation of neon by nuclear particles and secondary electrons. (lasers and active media)

  16. Kinetics of the nitrogen first negative system excitation by ionising radiation

    SciTech Connect

    Khasenov, M U

    2005-12-31

    The rate constants of N{sub 2}{sup +}(B) quenching by nitrogen and helium and of two- and three-body charge exchange of He{sub 2}{sup +} on H{sub 2}, D{sub 2}, and Kr are measured from luminescence at the 0-0 transition of the first negative system of nitrogen in mixtures of helium and nitrogen with hydrogen, krypton or deuterium excited by alpha particles emitted by {sup 210}Po . (active media)

  17. Oxidation of amylose and amylopectin by hydroxyl radicals assessed by electrospray ionisation mass spectrometry.

    PubMed

    Simões, Joana; Moreira, Ana S P; da Costa, Elisabete; Evtyugin, Dmitry; Domingues, Pedro; Nunes, Fernando M; Coimbra, Manuel A; Domingues, M Rosário M

    2016-09-01

    The hydroxyl radicals (HO) are one of the most reactive oxygen species (ROS) involved in the oxidative damage of biological molecules, including carbohydrates. During the industrial processing of food, ROS can be formed. In order to identify the structural changes induced in starch by oxidation, amylose, amylopectin, and maltotriose, an oligosaccharide structurally related to these polysaccharides, were subjected to oxidation with HO generated under Fenton reaction conditions (Fe(2+)/H2O2). The oxidised polysaccharides were hydrolysed by α-amylase and the obtained oligosaccharides were fractionated by ligand-exchange/size-exclusion chromatography. Both acidic and neutral α-amylase resistant oligosaccharides were characterized by mass spectrometry. In oxidised neutral products, new keto, hydroxyl, and hydroperoxy moieties, and oxidative ring scission were observed at the reducing end of the oligosaccharides. The acid sugar residues occurred at the reducing end and included gluconic and glucuronic acid derivatives, and acids formed by oxidative ring scission, namely, arabinonic, erythronic, glyceric and glycolic acids. PMID:27185142

  18. Models relating the radio emission and ionised gas in Seyfert nuclei

    NASA Technical Reports Server (NTRS)

    Pedlar, A.; Unger, S. W.; Axon, D. J.; Dyson, J. E.

    1987-01-01

    Possible models are discussed in which the radio emitting components in Seyfert II nuclei can compress and accelerate the ambient nuclear medium to produce the characteristics of the narrow line region. A first order model, which considers only the expansion of the radio components, is briefly described. However, in many Seyfert nuclei it appears that the linear motion of the radio components is also important. This can result in shock heating of the ambient medium, and if the cooling time is long enough, can lead to a displacement between the radio component and the associated emission lines. This effect may be present in NGC 1068 and NGC 5929 and by considering ram pressure balance and the cooling length it is possible to estimate lobe velocities and ambient densities.

  19. Combined effects of depleted uranium and ionising radiation on zebrafish embryos.

    PubMed

    Ng, C Y P; Pereira, S; Cheng, S H; Adam-Guillermin, C; Garnier-Laplace, J; Yu, K N

    2015-11-01

    In the environment, living organisms are exposed to a mixture of stressors, and the combined effects are deemed as multiple stressor effects. In the present work, the authors studied the multiple stressor effect in embryos of the zebrafish (Danio rerio) from simultaneous exposure to alpha particles and depleted uranium (DU) through quantification of apoptotic signals at 24 h post-fertilisation (hpf) revealed by vital dye acridine orange staining. In each set of experiments, dechorionated zebrafish embryos were divided into 4 groups, each having 10 embryos: Group (C) in which the embryos did not receive any further treatment; Group (IU) in which the embryos received an alpha-particle dose of 0.44 mGy at 5 hpf and were then exposed to 100 µg l(-1) of DU from 5 to 6 hpf; Group (I) in which the embryos received an alpha-particle dose of 0.44 mGy at 5 hpf and Group (U) in which the dechorionated embryos were exposed to 100 µg l(-1) of DU from 5 to 6 hpf. The authors confirmed that an alpha-particle dose of 0.44 mGy and a DU exposure for 1 h separately led to hormetic and toxic effects assessed by counting apoptotic signals, respectively, in the zebrafish. Interestingly, the combined exposure led to an effect more toxic than that caused by the DU exposure alone, so effectively DU changed the beneficial effect (hormesis) brought about by alpha-particle irradiation into an apparently toxic effect. This could be explained in terms of the promotion of early death of cells predisposed to spontaneous transformation by the small alpha-particle dose (i.e. hormetic effect) and the postponement of cell death upon DU exposure. PMID:25948823

  20. Pre-Service Teachers' Subject Knowledge of and Attitudes about Radioactivity and Ionising Radiation

    ERIC Educational Resources Information Center

    Colclough, Nicholas Denys; Lock, Roger; Soares, Allan

    2011-01-01

    This study focussed on secondary school (11-18 years) pre-service teachers' (n = 73) knowledge of and attitudes towards risks associated with alpha, beta, and gamma radiations. A multi-method approach was used with physics, chemistry, biology, and history graduates undertaking the one-year initial teacher training, Post Graduate Certificate in…

  1. Caracterisation, modelisation et validation du transfert radiatif d'atmospheres non standard; impact sur les corrections atmospheriques d'images de teledetection

    NASA Astrophysics Data System (ADS)

    Zidane, Shems

    This study is based on data acquired with an airborne multi-altitude sensor on July 2004 during a nonstandard atmospheric event in the region of Saint-Jean-sur-Richelieu, Quebec. By non-standard atmospheric event we mean an aerosol atmosphere that does not obey the typical monotonic, scale height variation employed in virtually all atmospheric correction codes. The surfaces imaged during this field campaign included a diverse variety of targets : agricultural land, water bodies, urban areas and forests. The multi-altitude approach employed in this campaign allowed us to better understand the altitude dependent influence of the atmosphere over the array of ground targets and thus to better characterize the perturbation induced by a non-standard (smoke) plume. The transformation of the apparent radiance at 3 different altitudes into apparent reflectance and the insertion of the plume optics into an atmospheric correction model permitted an atmospheric correction of the apparent reflectance at the two higher altitudes. The results showed consistency with the apparent validation reflectances derived from the lowest altitude radiances. This approach effectively confirmed the accuracy of our non-standard atmospheric correction approach. This test was particularly relevant at the highest altitude of 3.17 km : the apparent reflectances at this altitude were above most of the plume and therefore represented a good test of our ability to adequately correct for the influence of the perturbation. Standard atmospheric disturbances are obviously taken into account in most atmospheric correction models, but these are based on monotonically decreasing aerosol variations with increasing altitude. When the atmospheric radiation is affected by a plume or a local, non-standard pollution event, one must adapt the existing models to the radiative transfer constraints of the local perturbation and to the reality of the measurable parameters available for ingestion into the model. The main inputs of this study were those normally used in an atmospheric correction : apparent at-sensor radiance and the aerosol optical depth (AOD) acquired using ground-based sunphotometry. The procedure we employed made use of a standard atmospheric correction code (CAM5S, for Canadian Modified 5S, which comes from the 5S radiative transfer model in the visible and near infrared) : however, we also used other parameters and data to adapt and correctly model the special atmospheric situation which affected the multi-altitude images acquired during the St. Jean field campaign. We then developed a modeling protocol for these atmospheric perturbations where auxiliary data was employed to complement our main data-set. This allowed for the development of a robust and simple methodology adapted to this atmospheric situation. The auxiliary data, i.e. meteorological data, LIDAR profiles, various satellite images and sun photometer retrievals of the scattering phase function, were sufficient to accurately model the observed plume in terms of a unusual, vertical distribution. This distribution was transformed into an aerosol optical depth profile that replaced the standard aerosol optical depth profile employed in the CAM5S atmospheric correction model. Based on this model, a comparison between the apparent ground reflectances obtained after atmospheric corrections and validation values of R*(0) obtained from the lowest altitude data showed that the error between the two was less than 0.01 rms. This correction was shown to be a significantly better estimation of the surface reflectance than that obtained using the atmospheric correction model. Significant differences were nevertheless observed in the non-standard solution : these were mainly caused by the difficulties brought about by the acquisition conditions, significant disparities attributable to inconsistencies in the co-sampling / co-registration of different targets from three different altitudes, and possibly modeling errors and / or calibration. There is accordingly room for improvement in our approach to dealing w

  2. Analyse du transfert de chaleur et de la perte de pression pour des ecoulements supercritiques dans le reacteur CANDU-SCWR

    NASA Astrophysics Data System (ADS)

    Zoghlami, Sarra

    The supercritical water reactor is one of the six concepts of generation IV nuclear reactors that has been selected by the International Generation IV Forum (GIF). Canada has chosen to conduct advanced research on this type of reactor. For the design and safety analysis of the reactor concept, the development of numerical simulation codes is needed. The ARTHUR code is a thermal-hydraulic computer code developed by Fassi-Fehri (2008), at the Ecole Polytechnique de Montreal, to analyse the CANDU-6 reactor. The purpose of this project is to modify this numerical code so that it can be used to treat the CANDU-SCWR. To calculate the coolant thermal-hydraulics properties in the fuel channel of a CANDU-SCWR, it was assumed that the water flows under supercritical conditions is a one-phase flow. Thus within this code, we developed the conservation equations for one-phase flow. Hydraulic resistance and heat transfer at supercritical pressure are two important aspects to be considered in the modeling of a fuel channel in a nuclear reactor. To choose the accurate correlation to predict the pressure friction factor, we compared numerical calculations, using different correlations found in literature, to experimental data. We concluded that the Garimella (2008) correlation is the most consistent, to be incorporated in the ARTHUR &barbelow;SCWR code. We proved that the choice of the friction factor correlation affects slightly the distribution of thermal-hydraulic properties in the fuel channel. Under supercritical conditions, water thermal-physical properties are characterized by significant variations in the pseudo-critical region. This behavior influences the forced convection heat transfer phenomena. To choose the adequate correlation to calculate the forced convection heat transfer coefficient, we compared numerical results to experimental data, and we found that the standard deviation given by Mokry et al. (2010) correlation is the lowest. In order to model the fuel channel, some geometrical simplifications are made. In fact, we assumed that the coolant flow in the fuel channel is represented by the flow around the fuel rod, bounded by the first crown. This simplified model was used for neutronic/thermal-hydraulic coupled calculation performed with neutronic codes DRAGON/DONJON (Varin et al., 2005), to analyse the thermal-hydraulic behavior of the fuel channel in CANDU-SCWR. We observed that the coolant density at the fuel rod external surface, at the sixth fuel bundle is 3.5 times lower than the average coolant density in the fuel channel. This puts into question the assumption of considering the supercritical water flow as an homogeneous flow and the ability to build a supercritical water nuclear reactor in CANDU type, i.e., with horizontal fuel channels. In order to validate ARTHUR &barbelow;SCWR code, we compared our results to SUBCHAN code (Jiang et al., 2009), which is a thermal-hydraulic code developed to analyze CANDU-SCWR. Both codes give the same shapes and orders of magnitude for the coolant average temperature and the cladding-surface temperature. The axial distribution of the centerline temperature in the fuel rod is different. This is due to the fact that the calculations performed by the SUBCHAN code are not coupled to a neutronic code. For this reason, the thermal power distributions differs in the two codes. The variation of the mass flow influences the forced convective heat transfer, so, the distribution of thermal-physical properties in the channel. In fact, if the mass flow is reduced by 50% compared to the nominal mass flow rate, following a pump failure, the external fuel rod surface temperature exceeds the melting point, which is between 1400°C and 1455°C. This phenomenon may results in the radioactive contamination of the environment.

  3. Apprentissage dans un Environnement Informatique: Possibilite, Nature, Transfert des Acquis (Learning within an Information Environment: Possibilities, Native, and Transfer of Ideas).

    ERIC Educational Resources Information Center

    Dagher, Antoine

    1996-01-01

    Examines possibilities for learning offered by a piece of software, Fonctuse, likely to encourage the linking of algebraic and graphical representations of functions. Studied the influence of prior algebraic knowledge on the cognitive processes and constructions of knowledge at play in this environment. (Author/MKR)

  4. Transfert de nickel, de cuivre et de zinc lors de la manipulation de pièces de monnaie : le cas du dirham marocain

    NASA Astrophysics Data System (ADS)

    Fournier, Paul-Guy; Nourtier, Alain; Monkade, Mohammed; Berrada, Khalid; Boughaleb, Hichame; Outzourhit, Abdelkader; Pichon, Rémy; Haut, Christian; Govers, Thomas

    2006-03-01

    When the euro was introduced, the fact that some coins contain nickel, which is known to be an allergen, gave rise to controversy. More generally, this raises the question of metal transfer from coins to skin. Morocco has used for decades one-dirham coins made of pure or alloyed nickel. Studying their wear, the labile metal on their surface and the transfer to fingers in handling may therefore be especially instructive. Weighing statistics for a sample of 401 coins confirm that cupronickel coins wear out more quickly than pure nickel coins and reveal that the dirham suffers a much stronger wear than other currencies for which wear statistics are available. SEM studies supplemented by ICP quantitative analyses show that the labile metal is mainly made up of chips, even after many handlings. These chips are often cupronickel, even on pure nickel coins, which shows that they are produced by the friction of coins against one another. Secondly, the surface of coins presents sweat residue with an important proportion of copper and a little nickel, which confirms that sweat dissolves surface copper. Depending on the alloy and date, coins have between 20 and 140 μg of labile copper and nickel, with a content of one quarter of nickel on cupronickel coins and about one half on pure nickel coins. The most worn cupronickel coins are the coins that present the largest amount of labile metal, and even labile nickel. In our experiments, the metal transfer to fingers when a cupronickel coin is handled for the first time represents between 4 and 9% of the labile metal and 0.05% of the annual wear. A simple and reliable test of nickel contamination consists in measuring the labile nickel. To cite this article: P.-G. Fournier et al., C. R. Physique 7 (2006).

  5. Etude theorique du jet de plasma supersonique a courant continu

    NASA Astrophysics Data System (ADS)

    Jodoin, Bertrand

    La déposition par plasma supersonique à courant continu permet d'obtenir une qualité de dépôt supérieure au jet subsonique. Un modèle numérique a été développé dans le but de mieux comprendre les mécanismes de transfert à l'intérieur de la tuyère et d'estimer l'influence des paramètres d'opération de la torche sur le jet à la sortie de la tuyère. Les équations d'Euler, auxquelles sont ajoutées l'effet Joule, la conduction et les pertes par rayonnement sont résolues à l'aide de la méthode de Jameson. Un schéma centré est utilisé pour résoudre les champs électriques. La sous-couche cathodique en déséquilibre thermodynamique est modélisée à l'aide du modèle simple de Morrow et Lowke. Quelques détails sur les aspects numériques facilitant la convergence du système sont donnés. Le modèle est validé pour un écoulement compressible classique et pour un jet de plasma supersonique à l'aide de résultats de la littérature. Les champs à l'intérieur de la tuyère sont analysés afin de déterminer l'influence de l'hydrogène, de l'intensité du courant et de la géométrie de la tuyère sur les caractéristiques de l'écoulement.

  6. Fast gas chromatographic residue analysis in animal feed using split injection and atmospheric pressure chemical ionisation tandem mass spectrometry.

    PubMed

    Tienstra, M; Portolés, T; Hernández, F; Mol, J G J

    2015-11-27

    Significant speed improvement for instrumental runtime would make GC–MS much more attractive for determination of pesticides and contaminants and as complementary technique to LC–MS. This was the trigger to develop a fast method (time between injections less than 10 min) for the determination of pesticides and PCBs that are not (or less) amenable to LC–MS. A key factor in achieving shorter analysis time was the use of split injection (1:10) which allowed the use of a much higher initial GC oven temperature. A shorter column (15 m), higher temperature ramp, and higher carrier gas flow rate (6 mL/min) further contributed to analysis-time reduction. Chromatographic resolution was slightly compromised but still well fit-for-purpose. Due to the high sensitivity of the technique used (GC–APCI-triple quadrupole MS/MS), quantification and identification were still possible down to the 10 μg/kg level, which was demonstrated by successful validation of the method for complex feed matrices according to EU guidelines. Other advantages of the method included a better compatibility of acetonitrile extracts (e.g. QuEChERS) with GC, and a reduced transfer of co-extractants into the GC column and mass spectrometer. PMID:26601712

  7. Assessing the performance under ionising radiation of lead tungstate scintillators for EM calorimetry in the CLAS12 Forward Tagger

    NASA Astrophysics Data System (ADS)

    Fegan, S.; Auffray, E.; Battaglieri, M.; Buchanan, E.; Caiffi, B.; Celentano, A.; Colaneri, L.; D`Angelo, A.; De Vita, R.; Dormenev, V.; Fanchini, E.; Lanza, L.; Novotny, R. W.; Parodi, F.; Rizzo, A.; Sokhan, D.; Tarasov, I.; Zonta, I.

    2015-07-01

    The well-established technology of electromagnetic calorimetry using Lead Tungstate crystals has recently seen an upheaval, with the closure of one of the most experienced large-scale suppliers of such crystals, the Bogoroditsk Technical Chemical Plant (BTCP), which was instrumental in the development of mass production procedures for PWO-II, the current benchmark for this scintillator. Obtaining alternative supplies of Lead Tungstate crystals matching the demanding specifications of contemporary calorimeter devices now presents a significant challenge to detector research and development programmes. In this paper we describe a programme of assessment carried out for the selection, based upon the performance under irradiation, of Lead Tungstate crystals for use in the Forward Tagger device, part of the CLAS12 detector in Hall B at Jefferson Lab. The crystals tested were acquired from SICCAS, the Shanghai Institute of Ceramics, Chinese Academy of Sciences. The tests performed are intended to maximise the performance of the detector within the practicalities of the crystal manufacturing process. Results of light transmission, before and after gamma ray irradiation, are presented and used to calculate dk, the induced radiation absorption coefficient, at 420 nm, the peak of the Lead Tungstate emission spectrum. Results for the SICCAS crystals are compared with identical measurements carried out on Bogoroditsk samples, which were acquired for the Forward Tagger development program before the closure of the facility. Also presented are a series of tests performed to determine the feasibility of recovering radiation damage to the crystals using illumination from an LED, with such illumination available in the Forward Tagger from a light monitoring system integral to the detector.

  8. Analysis and characterisation of bovine oocyte and embryo biomarkers by matrix-assisted desorption ionisation mass spectrometry imaging.

    PubMed

    Gonçalves, Roseli F; Ferreira, Mónica S; de Oliveira, Diogo N; Canevarolo, Rafael; Achilles, Marcos A; D'Ercole, Daniela L; Bols, Peter E; Visintin, Jose A; Killian, Gary J; Catharino, Rodrigo R

    2016-03-01

    In the field of 'single cell analysis', many classical strategies like immunofluorescence and electron microscopy are the primary techniques of choice. However, these methodologies are time consuming and do not permit direct identification of specific molecular classes, such as lipids. In the present study, a novel mass spectrometry-based analytical approach was applied to bovine oocytes and embryos. This new metabolomics-based application uses mass spectrometry imaging (MSI), efficient data processing and multivariate data analysis. Metabolic fingerprinting (MF) was applied to the analysis of unfertilised oocytes, 2-, 4- and 8-cell embryos and blastocysts. A semiquantitative strategy for sphingomyelin [SM (16:0)+Na](+) (m/z 725) and phosphatidylcholine [PC (32:0)+Na](+) (m/z 756) was developed, showing that lipid concentration was useful for selecting the best metabolic biomarkers. This study demonstrates that a combination of MF, MSI features and chemometric analysis can be applied to discriminate cell stages, characterising specific biomarkers and relating them to developmental pathways. This information furthers our understanding of fertilisation and preimplantation events during bovine embryo development. PMID:25228254

  9. A gas ionisation detector in the axial (Bragg) geometry used for the time-of-flight elastic recoil detection analysis

    SciTech Connect

    Siketić, Zdravko; Skukan, Natko; Bogdanović Radović, Iva

    2015-08-15

    In this paper, time-of-flight elastic recoil detection analysis spectrometer with a newly constructed gas ionization detector for energy detection is presented. The detector is designed in the axial (Bragg) geometry with a 3 × 3 array of 50 nm thick Si{sub 3}N{sub 4} membranes as an entrance window. 40 mbar isobutane gas was sufficient to stop a 30 MeV primary iodine beam as well as all recoils in the detector volume. Spectrometer and detector performances were determined showing significant improvement in the mass and energy resolution, respectively, comparing to the spectrometer with a standard silicon particle detector for an energy measurement.

  10. On the populating mechanisms of the autoionising states of Al III ions produced in a Penning ionisation discharge

    NASA Technical Reports Server (NTRS)

    Finkenthal, M.; Littman, A.; Stutman, D.; Bhatia, A. K.

    1989-01-01

    Spectra emitted by Al II and Al III in the 100-1900-A range from a Penning ionization discharge (PID) have been analyzed in order to study the populating mechanisms of the autoionizing levels of the Al III ion. Electron temperature and density estimates and Al III line intensities obtained using a collisional-radiative model are found to differ from those obtained experimentally, implying that the autoionizing levels of the Na I-like ion may be populated, in the PID plasma, by the inner-shell ionization of excited Mg I-like ions. It is suggested that such autoionizing lines could be used to search for populations inversions in the soft X-ray domain.

  11. An evaluation of the shielding effectiveness of lead aprons used in clinics for protection against ionising radiation from novel radioisotopes.

    PubMed

    Deb, Pradip; Jamison, Robert; Mong, Lisa; U, Paul

    2015-07-01

    The purpose of this study is to evaluate the effectiveness of personal radiation shields currently worn in hospital and other diagnostic environments. This study was performed with four different radioisotopes; (18)F, (99m)Tc, (124)I and (131)I. (18)F results showed a decrease in dose with 0.5-mm Pb shielding but the reduction provided does not warrant its use clinically. (124)I testing demonstrated that dose enhancement can occur in greater shield thicknesses. PET isotope (124)I can be adequately shielded using 0.25-mm Pb equivalent aprons but any higher thickness increase the wearer's dose. As a result more shielding does not always equal more protection. The (131)I test showed that no dose reduction occurred, even when tested with up to 1.25-mm Pb equivalent shielding. Novel radioisotopes being used in the laboratory and clinic should be individually tested as each requires specific shielding testing. PMID:25848112

  12. Application of an ion mobility spectrometer with pulsed ionisation source in the detection of dimethyl methylphosphonate and toluene diisocyanate

    NASA Astrophysics Data System (ADS)

    Baether, Wolfgang; Zimmermann, Stefan; Gunzer, Frank

    2011-06-01

    Ion mobility spectrometry (IMS) is a well known technique; offering small size and a sensitivity in the ppb range makes it a typical technique for the detection of explosives or chemical warfare agents. Ordinary IMS devices use in general a continuously working radioactive ionization source. We use a pulsed non-radioactive electron source for ionization which offers the innovative possibility of introducing delay times in between ionization and ion detection. The application and benefits of such a pulsed ionization source in the detection of the chemical warfare agent simulant dimethyl methylphosphonate (DMMP) and the toxic toluene diisocyanate (TDI) will be demonstrated.

  13. Liquid chromatography/electrospray ionisation-tandem mass spectrometry quantification of GM2 gangliosides in human peripheral cells and plasma.

    PubMed

    Fuller, Maria; Duplock, Stephen; Hein, Leanne K; Rigat, Brigitte A; Mahuran, Don J

    2014-08-01

    GM2 gangliosidosis is a group of inherited neurodegenerative disorders resulting primarily from the excessive accumulation of GM2 gangliosides (GM2) in neuronal cells. As biomarkers for categorising patients and monitoring the effectiveness of developing therapies are lacking for this group of disorders, we sought to develop methodology to quantify GM2 levels in more readily attainable patient samples such as plasma, leukocytes, and cultured skin fibroblasts. Following organic extraction, gangliosides were partitioned into the aqueous phase and isolated using C18 solid-phase extraction columns. Relative quantification of three species of GM2 was achieved using LC/ESI-MS/MS with d35GM1 18:1/18:0 as an internal standard. The assay was linear over the biological range, and all GM2 gangliosidosis patients were demarcated from controls by elevated GM2 in cultured skin fibroblast extracts. However, in leukocytes only some molecular species could be used for differentiation and in plasma only one was informative. A reduction in GM2 was easily detected in patient skin fibroblasts after a short treatment with media from normal cells enriched in secreted β-hexosaminidase. This method may show promise for measuring the effectiveness of experimental therapies for GM2 gangliosidosis by allowing quantification of a reduction in the primary storage burden. PMID:24769373

  14. Deoxyribonucleic acid damage-associated biomarkers of ionising radiation: current status and future relevance for radiology and radiotherapy

    PubMed Central

    Rothkamm, K

    2013-01-01

    Diagnostic and therapeutic radiation technology has developed dramatically in recent years, and its use has increased significantly, bringing clinical benefit. The use of diagnostic radiology has become widespread in modern society, particularly in paediatrics where the clinical benefit needs to be balanced with the risk of leukaemia and brain cancer increasing after exposure to low doses of radiation. With improving long-term survival rates of radiotherapy patients and the ever-increasing use of diagnostic and interventional radiology procedures, concern has risen over the long-term risks and side effects from such treatments. Biomarker development in radiology and radiotherapy has progressed significantly in recent years to investigate the effects of such use and optimise treatment. Recent biomarker development has focused on improving the limitations of established techniques by the use of automation, increasing sensitivity and developing novel biomarkers capable of quicker results. The effect of low-dose exposure (0–100 mGy) used in radiology, which is increasingly linked to cancer incidences, is being investigated, as some recent research challenges the linear-no-threshold model. Radiotherapy biomarkers are focused on identifying radiosensitive patients, determining the treatment-associated risk and allowing for a tailored and more successful treatment of cancer patients. For biomarkers in any of these areas to be successfully developed, stringent criteria must be applied in techniques and analysis of data to reduce variation among reports and allow data sets to be accurately compared. Newly developed biomarkers can then be used in combination with the established techniques to better understand and quantify the individual biological response to exposures associated with radiology tests and to personalise treatment plans for patients. PMID:23659923

  15. Analysis of the quasicontinuum band emitted by highly ionised tungsten atoms in the 4-7 nm range

    NASA Astrophysics Data System (ADS)

    Madeira, Teresa Isabel; Amorim, Pedro; Parente, Fernando; Indelicato, Paul; Marques, José Pires

    2013-01-01

    Spectra emitted by highly ionized tungsten atoms from magnetically confined plasmas show a common feature: a narrow structured quasi-continuum emission band most prominent in the range 4-7 nm, which accounts for 40-80% of the radiated power. This band has been fairly well explained by unresolved transitions from groups 4 d-4 p, 4 f-4 d ( Δn = 0) and 5 d-4 f, 5 g-4 f and 5 p-4 d ( Δn = 1). In this work we use a Multi-Configuration Dirac-Fock code in Breit self-consistent field mode to compute level energies and transition probabilities for W27+ to W37+ ions contributing to this emission band. Intra-shell correlation was introduced in the calculation for both initial and final states and all dipole and quadrupole radiative transitions have been considered. The wavefunctions in the initial and final states are optimized separately and the resulting non-orthogonality effect is fully taken into account. The importance of some satellite lines was assessed. Together with the ionic distributions obtained by using the FLYCHK application and assuming that the initial states population depends statistically on the temperature we were able to synthesize plasma emission spectrum profiles for several electron temperatures.

  16. Ionising radiation and risk of death from leukaemia and lymphoma in radiation-monitored workers (INWORKS): an international cohort study

    PubMed Central

    Leuraud, Klervi; Richardson, David B; Cardis, Elisabeth; Daniels, Robert D; Gillies, Michael; O'Hagan, Jacqueline A; Hamra, Ghassan B; Haylock, Richard; Laurier, Dominique; Moissonnier, Monika; Schubauer-Berigan, Mary K; Thierry-Chef, Isabelle; Kesminiene, Ausrele

    2015-01-01

    Summary Background There is much uncertainty about the risks of leukaemia and lymphoma after repeated or protracted low-dose radiation exposure typical of occupational, environmental, and diagnostic medical settings. We quantified associations between protracted low-dose radiation exposures and leukaemia, lymphoma, and multiple myeloma mortality among radiation-monitored adults employed in France, the UK, and the USA. Methods We assembled a cohort of 308 297 radiation-monitored workers employed for at least 1 year by the Atomic Energy Commission, AREVA Nuclear Cycle, or the National Electricity Company in France, the Departments of Energy and Defence in the USA, and nuclear industry employers included in the National Registry for Radiation Workers in the UK. The cohort was followed up for a total of 8·22 million person-years. We ascertained deaths caused by leukaemia, lymphoma, and multiple myeloma. We used Poisson regression to quantify associations between estimated red bone marrow absorbed dose and leukaemia and lymphoma mortality. Findings Doses were accrued at very low rates (mean 1·1 mGy per year, SD 2·6). The excess relative risk of leukaemia mortality (excluding chronic lymphocytic leukaemia) was 2·96 per Gy (90% CI 1·17–5·21; lagged 2 years), most notably because of an association between radiation dose and mortality from chronic myeloid leukaemia (excess relative risk per Gy 10·45, 90% CI 4·48–19·65). Interpretation This study provides strong evidence of positive associations between protracted low-dose radiation exposure and leukaemia. Funding Centers for Disease Control and Prevention, Ministry of Health, Labour and Welfare of Japan, Institut de Radioprotection et de Sûreté Nucléaire, AREVA, Electricité de France, National Institute for Occupational Safety and Health, US Department of Energy, US Department of Health and Human Services, University of North Carolina, Public Health England. PMID:26436129

  17. Resveratrol Inhibits Ionising Irradiation-Induced Inflammation in MSCs by Activating SIRT1 and Limiting NLRP-3 Inflammasome Activation

    PubMed Central

    Fu, Yue; Wang, Yan; Du, Liqing; Xu, Chang; Cao, Jia; Fan, Tiqiang; Liu, Jianxiang; Su, Xu; Fan, Saijun; Liu, Qiang; Fan, Feiyue

    2013-01-01

    IL-1β, a pro-inflammatory cytokine, has been shown to contribute to radiation injury. Sirt1, an NAD+-dependent class III protein deacetylase, plays an important role in the regulation of the proinflammatory cytokines involved in inflammation-associated diseases. The relationship between Sirt1 and IL-1β, however, has remained elusive. The present study was designed to explore the potential effect of Sirt1 on IL-1β expression induced by radiation and to provide a new target for the development of radiation protection drugs. Our results showed that radiation significantly increased IL-1β mRNA and protein expression and that pretreatment with resveratrol, a Sirt1 activator, inhibited the radiation-induced IL-1β expression in a concentration-dependent manner, whereas the knockdown or inhibition of Sirt1 by nicotinamide significantly enhanced radiation-induced IL-1β expression. This effect can likely be attributed to Sirt1-mediated inhibition of NLRP-3 inflammasome activation because Sirt1 inhibits the transactivation potential of NF-κb by deacetylation, which then suppresses NLRP3 transcription. Taken together, the results demonstrate that Sirt1 exerts anti-inflammatory effects by regulating NLRP3 expression partially through the NF-κb pathway in mesenchymal stem cells. More importantly, our findings suggest that resveratrol is an effective agent in protecting against radiation injury, and we provide a theoretical basis for developing a drug to protect against radiation injury by targeting Sirt1. PMID:23880858

  18. SU-E-T-228: Liquid Ionisation Chamber Array and MicroDiamond Measurements with the CyberKnife System

    SciTech Connect

    Poppinga, D; Looe, H; Stelljes, T; Poppe, B; Blanck, O; Harder, D

    2014-06-01

    Purpose: The aim of this study was to measure the dose profile and output factors with a CyberKnife accelerator using a TM60019 microDiamond detector and a 1000SRS liquid chamber array (both PTW Freiburg, Germany). Methods: An MP3 water phantom (PTW, Freiburg) was positioned along the robotic world coordinate system. The TM60019 detector was adjusted to the center of the according fields and the semiconductor axis was aligned with the beam direction. Profiles at 5cm water depth and SSD = 80 cm were measured along the robotic x axis and y axis for the cylindrical collimators of the CyberKnife (diameter 60, 50, 40, 30, 20, 15, 12.5, 10, 7.5 and 5mm). To determine the output factors the dose profile was measured at 0.1 mm steps around the field center to find the maximum dose value. The liquid chamber array (1000SRS) measurement was performed with the same setup, but with RW3 buildup. Results: The 1000SRS measurements closely conform with the TM60019 profile measurement in all profile regions and for all collimator sizes. The profile measurement is influenced by the almost equal spatial resolution of the TM60019 detector (radius of the sensitive area 1.1mm) and of the 1000SRS liquid chamber array (single chamber width 2.3mm). The measured dose profiles have not been corrected for this limited spatial resolution. Rather we purpose to consider that spatial dose averaging over 2 mm wide regions might be justified in view of patient positioning inaccuracies and of the spaces in tissue participating in the biological radiation responses. Conclusion: The 1000SRS data points conform with the TM60019 profile measurements at all profile regions showing the applicability of liquid ion chamber arrays with the CyberKnife system.

  19. A new approach to studying the effects of ionising radiation on single cells using FTIR synchrotron microspectroscopy

    NASA Astrophysics Data System (ADS)

    Lipiec, E.; Birarda, G.; Kowalska, J.; Lekki, J.; Vaccari, L.; Wiecheć, A.; Wood, B. R.; Kwiatek, W. M.

    2013-12-01

    The effect of ionizing radiation on single cells using a proton source was investigated using Fourier transform infrared (FTIR) microspectroscopy. The prostate cancer cells (DU-145) were irradiated by a specific number (50, 200, 400, 2000 and 4000) of protons per cell. Next after fixing the cells with 70% ethanol micro-FTIR spectra were obtained using both: (a) the synchrotron radiation source with a Mercury-Cadmium-Telluride (MCT) detector and (b) a globar source with a focal plane array (FPA) detector. FTIR spectra obtained from both instrumental configurations were analyzed independently to investigate the changes in the DNA phosphodiester region (1150-950 cm-1) of irradiated and control (untreated by ionizing radiation) cells. A Principal Component Analysis (PCA) scores plot revealed distinct clusters for all groups of irradiated cells, even for those irradiated by the smallest dose of protons. The dose-dependent changes in the relative intensities of DNA peak at 970 cm-1 (ribose-phosphate skeletal motions), along with a shift of the O-P-O band corresponding to the symmetric phosphodiester stretching mode at 1090 cm-1 were observed. The results demonstrate that FTIR spectroscopy is a promising tool to investigate DNA damage in single cells and may become an important tool in assessing cell damage following radiotherapy.

  20. Alkali metal cation complexation by 1,3-alternate, mono-ionisable calix[4]arene-benzocrown-6 compounds

    DOE PAGESBeta

    Surowiec, Malgorzata A.; Custelcean, Radu; Surowiec, Kazimierz; Bartsch, Richard A.

    2014-04-23

    Alkali metal cation extraction behavior for two series of 1,3-alternate, mono-ionizable calix[4]arene-benzocrown-6 compounds is examined. In Series 1, the proton-ionizable group is a substituent on the benzo group of the polyether ring that directs it away from the crown ether cavity. In Series 2, the proton-ionizable group is attached to one para position in the calixarene framework, thus positioning it over the crown ether ring. Competitive solvent extraction of alkali metal cations from aqueous solutions into chloroform shows high Cs+ efficiency and selectivity. Single-species extraction pH profiles of Cs+ for Series 1 and 2 ligands with the same proton-ionizable groupmore » are very similar. Thus, association of Cs+ with the calixcrown ring is more important than the the proton-ionizable group’s position in relation to the crown ether cavity. Solid-state structures are presented for two unionized ligands from Series 2, as is a crystal containing two different ionized ligand–Cs+ complexes.« less

  1. Alkali metal cation complexation by 1,3-alternate, mono-ionisable calix[4]arene-benzocrown-6 compounds

    SciTech Connect

    Surowiec, Malgorzata A.; Custelcean, Radu; Surowiec, Kazimierz; Bartsch, Richard A.

    2014-04-23

    Alkali metal cation extraction behavior for two series of 1,3-alternate, mono-ionizable calix[4]arene-benzocrown-6 compounds is examined. In Series 1, the proton-ionizable group is a substituent on the benzo group of the polyether ring that directs it away from the crown ether cavity. In Series 2, the proton-ionizable group is attached to one para position in the calixarene framework, thus positioning it over the crown ether ring. Competitive solvent extraction of alkali metal cations from aqueous solutions into chloroform shows high Cs+ efficiency and selectivity. Single-species extraction pH profiles of Cs+ for Series 1 and 2 ligands with the same proton-ionizable group are very similar. Thus, association of Cs+ with the calixcrown ring is more important than the the proton-ionizable group’s position in relation to the crown ether cavity. Solid-state structures are presented for two unionized ligands from Series 2, as is a crystal containing two different ionized ligand–Cs+ complexes.

  2. Effects of Partially Ionised Medical Oxygen, Especially with O2•−, in Vibration White Finger Patients

    PubMed Central

    Perečinský, Slavomír; Murínová, Lenka; Engler, Ivan; Donič, Viliam; Murín, Pavol; Varga, Marek; Legáth, Ľubomír

    2014-01-01

    A major symptom of hand-arm vibration syndrome is a secondary Raynaud’s phenomenon—vibration white finger (VWF)—which results from a vasospasm of the digital arteries caused by work with vibration devices leading to occupational disease. Pharmacotherapy of VWF is often ineffective or has adverse effects. The aim of this work was to verify the influence of inhalation of partially ionized oxygen (O2•−) on peripheral blood vessels in the hands of patients with VWF. Ninety one (91)patients with VWF underwent four-finger adsorption plethysmography, and the pulse wave amplitude was recorded expressed in numeric parameters—called the native record. Next, a cold water test was conducted following with second plethysmography. The patients were divided in to the three groups. First and second inhaled 20-min of ionized oxygen O2•− or oxygen O2 respectively. Thirth group was control without treatment. All three groups a follow-up third plethysmography—the post-therapy record. Changes in the pulse wave amplitudes were evaluated. Inpatients group inhaling O2•− a modest increase of pulse wave amplitude was observed compared to the native record; patients inhaling medical oxygen O2 and the control showed a undesirable decline of pulse wave amplitude in VWF fingers. Strong vasodilatation were more frequent in the group inhaling O2•− compare to O2 (p < 0.05). Peripheral vasodilatation achieved by inhalation of O2•− could be used for VWF treatment without undesirable side effect in hospital as well as at home environment. PMID:24871260

  3. An electrospray ionisation-mass spectrometry screening of triacylglycerols in developing cultivated and wild peanut kernels (Arachis hypogaea L.).

    PubMed

    Cherif, Aicha O; Leveque, Nathalie; Ben Messaouda, Mhamed; Kallel, Habib; Moussa, Fathi

    2013-06-01

    The accumulation of triacylglycerols during the development of three varieties of peanuts was monitored in two Tunisian cultivated peanut (Trabelsia (AraT) and Chounfakhi (AraC)) and one wild Tunisian peanut (Arbi (AraA)). The presence of TAGs composed of rare fatty acid residues such as hexacosanoic acid (C(23:0)) and heneicosanoic acid (C(21:0)) among the triacylglycerols C(23:0) LL, C(23:0) OO and C(21:0) LL was noted. The major molecular species of triacylglycerol detected in the three peanut varieties were dioleoyl linoleoyl (OOL), 1,2,3-trioleyl (OOO), 1,2-dioleyl-3-palmitoyl (POO), 1,2-dilinoleoyl-3-oleyl (OLL) and 1-oleoyl-2-linoleoyl-3-linolenoyl (OLLn). The TAG composition and content were significantly different among the three peanut varieties. The three major TAGs were OOL (20.6%), OOO (15.6%) and OLLn (13.2%) in AraA; OOL (21.4%), OOO (20.1%) and POO (17.5%) in AraC and finally OLL (20.7%), OOO (19.8%) and OLL (17.7%) in AraT. PMID:23411219

  4. Le rôle des plantes dans le transfert du silicium à la surface des continentsThe role of plants in the transfer of silicon at the surface of the continents

    NASA Astrophysics Data System (ADS)

    Meunier, Jean-Dominique

    2003-12-01

    Silicon is the most abundant element after oxygen in the lithosphere (27 wt%). Plants and soil microorganisms are important contributors to the weathering of silicates. Plants are able to accumulate several percent of Si in the biomass. The importance of plants in the rates of Si output to surface waters is discussed in this paper. To cite this article: J.-D. Meunier, C. R. Geoscience 335 (2003).

  5. Etude du transfert de quelques oligo-éléments dans les chaînes trophiques néritiques et estuariennes: Accumulation biologique chez les poissons omnivores et super-carnivores

    NASA Astrophysics Data System (ADS)

    Metayer, C.; Amiard, J.-C.; Amiard-Triquet, C.; Marchand, J.

    1980-06-01

    Five species of fishes (Dicentrarchus labrax, Gobius microps, Stizostedion lucioperca, Gadus luscus, Merlangius merlangus) and their major prey organisms were collected monthly from two stations in the Loire estuary (France). The levels of several trace elements (Cd, Pb, Cu, Zn) in their tissues were determined by means of atomic absorption spectrophotometry. The concentrations of Cd, Pb and Cu were shown to decrease in the highest trophic levels: the relatively highest metal levels were determined in annelids, followed by crustaceans, the lowest levels being encountered in fishes. However, a preferential uptake of Cu was observed in crustaceans. There is no biomagnification for these three metals, the concentrations in preys being generally lower than in predators. For Zn, the highest concentrations were measured in worms and copepods but preys such as shrimps and mysids exhibit values of the same order of magnitude compared to predator fishes.

  6. Couplage des équations de transfert de masse et des lois d'interactions solution-solide par l'utilisation des lanthanides comme traceurs — Approche expérimentale

    NASA Astrophysics Data System (ADS)

    Bigot, S.; Treuil, M.; Dumonceau, J.; Fromage, F.

    1984-02-01

    In underground flow tracing studies, the estimation of the nature and the importance of interactions undergone by the substance used very often constitutes an obstacle to good modeling of mass-transfer processes in solution. We propose a method to quantify these phenomena by the use of lanthanides as tracers. For this study, we set up an analytical methodology adapted to routine measurements. The quality of five lanthanides as indicators has been examined. We have demonstrated the formation, by substitution, of a carbonate complex which is extremely stable in the natural environment. The field experiments carried out demonstrated the efficiency of those tracers and confirmed their great stability. Tracer recovery graphs show that, in accord with our hypothesis, convection and dispersion are identical for all the lanthanide elements. Moreover, we have established a direct relation between their fixing rate on earth materials and the value of their stability constants. Thus, we demonstrate the possibility of correlative multitracing, with known and quantifiable interelement relations.

  7. Search for metastable heavy charged particles with large ionisation energy loss in pp collisions at ${\\sqrt{s} = 8}$ s = 8 TeV using the ATLAS experiment

    SciTech Connect

    Aad, G.

    2015-09-03

    Many extensions of the Standard Model predict the existence of charged heavy long-lived particles, such as R-hadrons or charginos. These particles, if produced at the Large Hadron Collider, should be moving non-relativistically and are therefore identifiable through the measurement of an anomalously large specific energy loss in the ATLAS pixel detector. Measuring heavy long-lived particles through their track parameters in the vicinity of the interaction vertex provides sensitivity to metastable particles with lifetimes from 0.6 ns to 30 ns. A search for such particles with the ATLAS detector at the Large Hadron Collider is presented, based on a data sample corresponding to an integrated luminosity of \\(18.4\\) fb\\(^{-1}\\) of pp collisions at \\(\\sqrt{s} = 8\\) TeV. No significant deviation from the Standard Model background expectation is observed, and lifetime-dependent upper limits on R-hadrons and chargino production are set. Gluino R-hadrons with 10 ns lifetime and masses up to 1185 GeV are excluded at 95 \\(\\%\\) confidence level, and so are charginos with 15 ns lifetime and masses up to 482 GeV.

  8. Monitoring radiation belt particle precipitation - automatic detection of enhanced transient ionisation in the lower plasmasphere using subionospheric narrow band VLF signals

    NASA Astrophysics Data System (ADS)

    Steinbach, P.; Lichtenberger, J.; Ferencz, Cs.

    2009-04-01

    Signals of naval VLF transmitters, propagating long distances along the Earth-ionosphere waveguide (EIWG) have been widely applied as effective tools for monitoring transient ionization at mesospheric altitudes. Perturbations in recorded amplitude and/or phase data series of stable frequency signals may refer to the effect of transient enhanced ionization in the EIWG, due to e.g. loss-cone precipitation of trapped energetic electrons (Carpenter et al., 1984, Dowden and Adams, 1990), burst of solar plasma particles (Clilverd et al., 2001). The contribution of precipitating particles are thought to be substantial in certain Sun-to-Earth energy flow processes in the upper atmosphere (Rodger et al., 2005). Narrow band VLF measuring network has been set up, developed and operated in Hungary, running in the last decade almost continuously, dedicated to monitor ionization enhancement regions along numerous transmitter-receiver paths. This setup is based on Omnipal and Ultra-MSK equipment, logging amplitude and phase data of received signals, sampled at frequencies of selected VLF transmitters. Signal trajectories, selected for recording represent proper configuration to survey transient ionization caused by energetic particles in the sub-polar region, such as effect of scattered particles of the inner radiation belt. Reprocessing of the mass archived recordings has been started using a newly developed signal processing code, detecting and classifying different sort of perturbations automatically on narrow band VLF series. Occurrence rates, daily and seasonal variation, statistics of transient ionization enhancements, their geographic distribution within the surveyed range and time period, and correlation with intense geomagnetic and/or Solar event is yielded by this analysis. References: Carpenter, D.L., Inan, U.S., Trimpi, M.L., Helliwell, R.A., and Katsufrakis, J.P.: Perturbations of subionospheric LF and MF signals due to whistler-induced electron precipitation burst, J.Geophys.Res., 89, A11, 9837-9862, 1984. Clilverd, M. A., Seppälä, A., Rodger, C.J., Thomson, N.R., Verronen, P.T., Turunen, E., Ulich, Th., Lichtenberger, J., and Steinbach, P.: Modelling polar ionospheric effects during the October-November 2003 solar proton events, Radio Sci., 41, RS2001, doi:10.1029/2005RS003290. Dowden, R.L., and Adams, C.D.D.: Lightning-induced perturbations on VLF subionospheric transmissions, J. Atmos. Terr. Phys., 52, 5, 357-363, 1990. Rodger, C.J., Clilverd, M.A., Thomson,N.R., Nunn, D., and Lichtenberger, J.: Lightning driven inner radiation belt energy deposition into the atmosphere: regional and global estimates, Ann. Geophys., 23, 3419-3430, 2005.

  9. Electrokinetic supercharging-electrospray ionisation-mass spectrometry for separation and on-line preconcentration of hypolipidaemic drugs in water samples.

    PubMed

    Dawod, Mohamed; Breadmore, Michael C; Guijt, Rosanne M; Haddad, Paul R

    2010-04-01

    Electrokinetic supercharging, a powerful on-line preconcentration technique in CE, was for the first time hyphenated with ESI-MS for the on-line concentration and separation of five hypolipidaemic drugs. The electrophoretic separation was performed in a co-EOF mode using the EOF reversal agent, hexadimethrine bromide, in ammonium bicarbonate electrolyte, pH 9.00. The ionic strength and the amount of methanol in the buffer were optimised in a multivariate manner using artificial neural networks, with the optimal conditions being 60 mM ammonium bicarbonate containing 60% methanol, providing baseline resolution of the five hypolipidaemics within 20 min. Using electrokinetic supercharging, the sensitivity of the method was improved 1000-fold over a conventional injection under field-amplified sample stacking conditions with LODs of 180 ng/L. This is the first report of the separation of hypolipidaemics by CE. The developed method was validated and then applied to the determination of the target drugs in water samples from Hobart city. PMID:20349512

  10. Search for metastable heavy charged particles with large ionisation energy loss in pp collisions at TeV using the ATLAS experiment

    NASA Astrophysics Data System (ADS)

    Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Aben, R.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Abreu, R.; Abulaiti, Y.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Adelman, J.; Adomeit, S.; Adye, T.; Affolder, A. A.; Agatonovic-Jovin, T.; Agricola, J.; Aguilar-Saavedra, J. A.; Ahlen, S. P.; Ahmadov, F.; Aielli, G.; Akerstedt, H.; Åkesson, T. P. A.; Akimov, A. V.; Alberghi, G. L.; Albert, J.; Albrand, S.; Alconada Verzini, M. J.; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexopoulos, T.; Alhroob, M.; Alimonti, G.; Alio, L.; Alison, J.; Alkire, S. P.; Allbrooke, B. M. M.; Allport, P. P.; Aloisio, A.; Alonso, A.; Alonso, F.; Alpigiani, C.; Altheimer, A.; Alvarez Gonzalez, B.; Álvarez Piqueras, D.; Alviggi, M. G.; Amadio, B. T.; Amako, K.; Amaral Coutinho, Y.; Amelung, C.; Amidei, D.; Amor Dos Santos, S. P.; Amorim, A.; Amoroso, S.; Amram, N.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anders, J. K.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Angelidakis, S.; Angelozzi, I.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Aperio Bella, L.; Arabidze, G.; Arai, Y.; Araque, J. P.; Arce, A. T. H.; Arduh, F. A.; Arguin, J.-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnal, V.; Arnold, H.; Arratia, M.; Arslan, O.; Artamonov, A.; Artoni, G.; Asai, S.; Asbah, N.; Ashkenazi, A.; Åsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Augsten, K.; Aurousseau, M.; Avolio, G.; Axen, B.; Ayoub, M. K.; Azuelos, G.; Baak, M. A.; Baas, A. E.; Baca, M. J.; Bacci, C.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Bagiacchi, P.; Bagnaia, P.; Bai, Y.; Bain, T.; Baines, J. T.; Baker, O. K.; Baldin, E. M.; Balek, P.; Balestri, T.; Balli, F.; Banas, E.; Banerjee, Sw.; Bannoura, A. A. E.; Bansil, H. S.; Barak, L.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnes, S. L.; Barnett, B. M.; Barnett, R. M.; Barnovska, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Bartoldus, R.; Barton, A. E.; Bartos, P.; Basalaev, A.; Bassalat, A.; Basye, A.; Bates, R. L.; Batista, S. J.; Batley, J. R.; Battaglia, M.; Bauce, M.; Bauer, F.; Bawa, H. S.; Beacham, J. B.; Beattie, M. D.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, M.; Becker, S.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bednyakov, V. A.; Bee, C. P.; Beemster, L. J.; Beermann, T. A.; Begel, M.; Behr, J. K.; Belanger-Champagne, C.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bender, M.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez Garcia, J. A.; Benjamin, D. P.; Bensinger, J. R.; Bentvelsen, S.; Beresford, L.; Beretta, M.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Beringer, J.; Bernard, C.; Bernard, N. R.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertoli, G.; Bertolucci, F.; Bertsche, C.; Bertsche, D.; Besana, M. I.; Besjes, G. J.; Bessidskaia Bylund, O.; Bessner, M.; Besson, N.; Betancourt, C.; Bethke, S.; Bevan, A. J.; Bhimji, W.; Bianchi, R. M.; Bianchini, L.; Bianco, M.; Biebel, O.; Biedermann, D.; Bieniek, S. P.; Biglietti, M.; Bilbao De Mendizabal, J.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biondi, S.; Black, C. W.; Black, J. E.; Black, K. M.; Blackburn, D.; Blair, R. E.; Blanchard, J.-B.; Blanco, J. E.; Blazek, T.; Bloch, I.; Blocker, C.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Bock, C.; Boehler, M.; Bogaerts, J. A.; Bogavac, D.; Bogdanchikov, A. G.; Bohm, C.; Boisvert, V.; Bold, T.; Boldea, V.; Boldyrev, A. S.; Bomben, M.; Bona, M.; Boonekamp, M.; Borisov, A.; Borissov, G.; Borroni, S.; Bortfeldt, J.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boudreau, J.; Bouffard, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozic, I.; Bracinik, J.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brazzale, S. F.; Breaden Madden, W. D.; Brendlinger, K.; Brennan, A. J.; Brenner, L.; Brenner, R.; Bressler, S.; Bristow, K.; Bristow, T. M.; Britton, D.; Britzger, D.; Brochu, F. M.; Brock, I.; Brock, R.; Bronner, J.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brosamer, J.; Brost, E.; Brown, J.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Bruni, A.; Bruni, G.; Bruschi, M.; Bruscino, N.; Bryngemark, L.; Buanes, T.; Buat, Q.; Buchholz, P.; Buckley, A. G.; Buda, S. I.; Budagov, I. A.; Buehrer, F.; Bugge, L.; Bugge, M. K.; Bulekov, O.; Bullock, D.; Burckhart, H.; Burdin, S.; Burgard, C. D.; Burghgrave, B.; Burke, S.; Burmeister, I.; Busato, E.; Büscher, D.; Büscher, V.; Bussey, P.; Butler, J. M.; Butt, A. I.; Buttar, C. M.; Butterworth, J. M.; Butti, P.; Buttinger, W.; Buzatu, A.; Buzykaev, A. R.; Cabrera Urbán, S.; Caforio, D.; Cairo, V. M.; Cakir, O.; Calace, N.; Calafiura, P.; Calandri, A.; Calderini, G.; Calfayan, P.; Caloba, L. P.; Calvet, D.; Calvet, S.; Camacho Toro, R.; Camarda, S.; Camarri, P.; Cameron, D.; Caminal Armadans, R.; Campana, S.; Campanelli, M.; Campoverde, A.; Canale, V.; Canepa, A.; Cano Bret, M.; Cantero, J.; Cantrill, R.; Cao, T.; Capeans Garrido, M. D. M.; Caprini, I.; Caprini, M.; Capua, M.; Caputo, R.; Cardarelli, R.; Cardillo, F.; Carli, T.; Carlino, G.; Carminati, L.; Caron, S.; Carquin, E.; Carrillo-Montoya, G. D.; Carter, J. R.; Carvalho, J.; Casadei, D.; Casado, M. P.; Casolino, M.; Castaneda-Miranda, E.; Castelli, A.; Castillo Gimenez, V.; Castro, N. F.; Catastini, P.; Catinaccio, A.; Catmore, J. R.; Cattai, A.; Caudron, J.; Cavaliere, V.; Cavalli, D.; Cavalli-Sforza, M.; Cavasinni, V.; Ceradini, F.; Cerio, B. C.; Cerny, K.; Cerqueira, A. S.; Cerri, A.; Cerrito, L.; Cerutti, F.; Cerv, M.; Cervelli, A.; Cetin, S. A.; Chafaq, A.; Chakraborty, D.; Chalupkova, I.; Chang, P.; Chapman, J. D.; Charlton, D. G.; Chau, C. C.; Chavez Barajas, C. A.; Cheatham, S.; Chegwidden, A.; Chekanov, S.; Chekulaev, S. V.; Chelkov, G. A.; Chelstowska, M. A.; Chen, C.; Chen, H.; Chen, K.; Chen, L.; Chen, S.; Chen, X.; Chen, Y.; Cheng, H. C.; Cheng, Y.; Cheplakov, A.; Cheremushkina, E.; Cherkaoui El Moursli, R.; Chernyatin, V.; Cheu, E.; Chevalier, L.; Chiarella, V.; Chiarelli, G.; Childers, J. T.; Chiodini, G.; Chisholm, A. S.; Chislett, R. T.; Chitan, A.; Chizhov, M. V.; Choi, K.; Chouridou, S.; Chow, B. K. B.; Christodoulou, V.; Chromek-Burckhart, D.; Chudoba, J.; Chuinard, A. J.; Chwastowski, J. J.; Chytka, L.; Ciapetti, G.; Ciftci, A. K.; Cinca, D.; Cindro, V.; Cioara, I. A.; Ciocio, A.; Citron, Z. H.; Ciubancan, M.; Clark, A.; Clark, B. L.; Clark, P. J.; Clarke, R. N.; Cleland, W.; Clement, C.; Coadou, Y.; Cobal, M.; Coccaro, A.; Cochran, J.; Coffey, L.; Cogan, J. G.; Colasurdo, L.; Cole, B.; Cole, S.; Colijn, A. P.; Collot, J.; Colombo, T.; Compostella, G.; Conde Muiño, P.; Coniavitis, E.; Connell, S. H.; Connelly, I. A.; Consonni, S. M.; Consorti, V.; Constantinescu, S.; Conta, C.; Conti, G.; Conventi, F.; Cooke, M.; Cooper, B. D.; Cooper-Sarkar, A. M.; Cornelissen, T.; Corradi, M.; Corriveau, F.; Corso-Radu, A.; Cortes-Gonzalez, A.; Cortiana, G.; Costa, G.; Costa, M. J.; Costanzo, D.; Côté, D.; Cottin, G.; Cowan, G.; Cox, B. E.; Cranmer, K.; Cree, G.; Crépé-Renaudin, S.; Crescioli, F.; Cribbs, W. A.; Crispin Ortuzar, M.; Cristinziani, M.; Croft, V.; Crosetti, G.; Cuhadar Donszelmann, T.; Cummings, J.; Curatolo, M.; Cuthbert, C.; Czirr, H.; Czodrowski, P.; D'Auria, S.; D'Onofrio, M.; Da Cunha Sargedas De Sousa, M. J.; Da Via, C.; Dabrowski, W.; Dafinca, A.; Dai, T.; Dale, O.; Dallaire, F.; Dallapiccola, C.; Dam, M.; Dandoy, J. R.; Dang, N. P.; Daniells, A. C.; Danninger, M.; Dano Hoffmann, M.; Dao, V.; Darbo, G.; Darmora, S.; Dassoulas, J.; Dattagupta, A.; Davey, W.; David, C.; Davidek, T.; Davies, E.; Davies, M.; Davison, P.; Davygora, Y.; Dawe, E.; Dawson, I.; Daya-Ishmukhametova, R. K.; De, K.; de Asmundis, R.; De Benedetti, A.; De Castro, S.; De Cecco, S.; De Groot, N.; de Jong, P.; De la Torre, H.; De Lorenzi, F.; De Nooij, L.; De Pedis, D.; De Salvo, A.; De Sanctis, U.; De Santo, A.; De Vivie De Regie, J. B.; Dearnaley, W. J.; Debbe, R.; Debenedetti, C.; Dedovich, D. V.; Deigaard, I.; Del Peso, J.; Del Prete, T.; Delgove, D.; Deliot, F.; Delitzsch, C. M.; Deliyergiyev, M.; Dell'Acqua, A.; Dell'Asta, L.; Dell'Orso, M.; Della Pietra, M.; della Volpe, D.; Delmastro, M.; Delsart, P. A.; Deluca, C.; DeMarco, D. A.; Demers, S.; Demichev, M.; Demilly, A.; Denisov, S. P.; Derendarz, D.; Derkaoui, J. E.; Derue, F.; Dervan, P.; Desch, K.; Deterre, C.; Deviveiros, P. O.; Dewhurst, A.; Dhaliwal, S.; Di Ciaccio, A.; Di Ciaccio, L.; Di Domenico, A.; Di Donato, C.; Di Girolamo, A.; Di Girolamo, B.; Di Mattia, A.; Di Micco, B.; Di Nardo, R.; Di Simone, A.; Di Sipio, R.; Di Valentino, D.; Diaconu, C.; Diamond, M.; Dias, F. A.; Diaz, M. A.; Diehl, E. B.; Dietrich, J.; Diglio, S.; Dimitrievska, A.; Dingfelder, J.; Dita, P.; Dita, S.; Dittus, F.; Djama, F.; Djobava, T.; Djuvsland, J. I.; do Vale, M. A. B.; Dobos, D.; Dobre, M.; Doglioni, C.; Dohmae, T.; Dolejsi, J.; Dolezal, Z.; Dolgoshein, B. A.; Donadelli, M.; Donati, S.; Dondero, P.; Donini, J.; Dopke, J.; Doria, A.; Dova, M. T.; Doyle, A. T.; Drechsler, E.; Dris, M.; Dubreuil, E.; Duchovni, E.; Duckeck, G.; Ducu, O. A.; Duda, D.; Dudarev, A.; Duflot, L.; Duguid, L.; Dührssen, M.; Dunford, M.; Duran Yildiz, H.; Düren, M.; Durglishvili, A.; Duschinger, D.; Dyndal, M.; Eckardt, C.; Ecker, K. M.; Edgar, R. C.; Edson, W.; Edwards, N. C.; Ehrenfeld, W.; Eifert, T.; Eigen, G.; Einsweiler, K.; Ekelof, T.; El Kacimi, M.; Ellert, M.; Elles, S.; Ellinghaus, F.; Elliot, A. A.; Ellis, N.; Elmsheuser, J.; Elsing, M.; Emeliyanov, D.; Enari, Y.; Endner, O. C.; Endo, M.; Erdmann, J.; Ereditato, A.; Ernis, G.; Ernst, J.; Ernst, M.; Errede, S.; Ertel, E.; Escalier, M.; Esch, H.; Escobar, C.; Esposito, B.; Etienvre, A. I.; Etzion, E.; Evans, H.; Ezhilov, A.; Fabbri, L.; Facini, G.; Fakhrutdinov, R. M.; Falciano, S.; Falla, R. J.; Faltova, J.; Fang, Y.; Fanti, M.; Farbin, A.; Farilla, A.; Farooque, T.; Farrell, S.; Farrington, S. M.; Farthouat, P.; Fassi, F.; Fassnacht, P.; Fassouliotis, D.; Faucci Giannelli, M.; Favareto, A.; Fayard, L.; Federic, P.; Fedin, O. L.; Fedorko, W.; Feigl, S.; Feligioni, L.; Feng, C.; Feng, E. J.; Feng, H.; Fenyuk, A. B.; Feremenga, L.; Fernandez Martinez, P.; Fernandez Perez, S.; Ferrando, J.; Ferrari, A.; Ferrari, P.; Ferrari, R.; Ferreira de Lima, D. E.; Ferrer, A.; Ferrere, D.; Ferretti, C.; Ferretto Parodi, A.; Fiascaris, M.; Fiedler, F.; Filipčič, A.; Filipuzzi, M.; Filthaut, F.; Fincke-Keeler, M.; Finelli, K. D.; Fiolhais, M. C. N.; Fiorini, L.; Firan, A.; Fischer, A.; Fischer, C.; Fischer, J.; Fisher, W. C.; Fitzgerald, E. A.; Flaschel, N.; Fleck, I.; Fleischmann, P.; Fleischmann, S.; Fletcher, G. T.; Fletcher, G.; Fletcher, R. R. M.; Flick, T.; Floderus, A.; Flores Castillo, L. R.; Flowerdew, M. J.; Formica, A.; Forti, A.; Fournier, D.; Fox, H.; Fracchia, S.; Francavilla, P.; Franchini, M.; Francis, D.; Franconi, L.; Franklin, M.; Frate, M.; Fraternali, M.; Freeborn, D.; French, S. T.; Friedrich, F.; Froidevaux, D.; Frost, J. A.; Fukunaga, C.; Fullana Torregrosa, E.; Fulsom, B. G.; Fusayasu, T.; Fuster, J.; Gabaldon, C.; Gabizon, O.; Gabrielli, A.; Gabrielli, A.; Gach, G. P.; Gadatsch, S.; Gadomski, S.; Gagliardi, G.; Gagnon, P.; Galea, C.; Galhardo, B.; Gallas, E. J.; Gallop, B. J.; Gallus, P.; Galster, G.; Gan, K. K.; Gao, J.; Gao, Y.; Gao, Y. S.; Garay Walls, F. M.; Garberson, F.; García, C.; García Navarro, J. E.; Garcia-Sciveres, M.; Gardner, R. W.; Garelli, N.; Garonne, V.; Gatti, C.; Gaudiello, A.; Gaudio, G.; Gaur, B.; Gauthier, L.; Gauzzi, P.; Gavrilenko, I. L.; Gay, C.; Gaycken, G.; Gazis, E. N.; Ge, P.; Gecse, Z.; Gee, C. N. P.; Geerts, D. A. A.; Geich-Gimbel, Ch.; Geisler, M. P.; Gemme, C.; Genest, M. H.; Gentile, S.; George, M.; George, S.; Gerbaudo, D.; Gershon, A.; Ghasemi, S.; Ghazlane, H.; Giacobbe, B.; Giagu, S.; Giangiobbe, V.; Giannetti, P.; Gibbard, B.; Gibson, S. M.; Gilchriese, M.; Gillam, T. P. S.; Gillberg, D.; Gilles, G.; Gingrich, D. M.; Giokaris, N.; Giordani, M. P.; Giorgi, F. M.; Giorgi, F. M.; Giraud, P. F.; Giromini, P.; Giugni, D.; Giuliani, C.; Giulini, M.; Gjelsten, B. K.; Gkaitatzis, S.; Gkialas, I.; Gkougkousis, E. L.; Gladilin, L. K.; Glasman, C.; Glatzer, J.; Glaysher, P. C. F.; Glazov, A.; Goblirsch-Kolb, M.; Goddard, J. R.; Godlewski, J.; Goldfarb, S.; Golling, T.; Golubkov, D.; Gomes, A.; Gonçalo, R.; Goncalves Pinto Firmino Da Costa, J.; Gonella, L.; González de la Hoz, S.; Gonzalez Parra, G.; Gonzalez-Sevilla, S.; Goossens, L.; Gorbounov, P. A.; Gordon, H. A.; Gorelov, I.; Gorini, B.; Gorini, E.; Gorišek, A.; Gornicki, E.; Goshaw, A. T.; Gössling, C.; Gostkin, M. I.; Goujdami, D.; Goussiou, A. G.; Govender, N.; Gozani, E.; Grabas, H. M. X.; Graber, L.; Grabowska-Bold, I.; Gradin, P. O. J.; Grafström, P.; Grahn, K.-J.; Gramling, J.; Gramstad, E.; Grancagnolo, S.; Gratchev, V.; Gray, H. M.; Graziani, E.; Greenwood, Z. D.; Gregersen, K.; Gregor, I. M.; Grenier, P.; Griffiths, J.; Grillo, A. A.; Grimm, K.; Grinstein, S.; Gris, Ph.; Grivaz, J.-F.; Grohs, J. P.; Grohsjean, A.; Gross, E.; Grosse-Knetter, J.; Grossi, G. C.; Grout, Z. J.; Guan, L.; Guenther, J.; Guescini, F.; Guest, D.; Gueta, O.; Guido, E.; Guillemin, T.; Guindon, S.; Gul, U.; Gumpert, C.; Guo, J.; Guo, Y.; Gupta, S.; Gustavino, G.; Gutierrez, P.; Gutierrez Ortiz, N. G.; Gutschow, C.; Guyot, C.; Gwenlan, C.; Gwilliam, C. B.; Haas, A.; Haber, C.; Hadavand, H. K.; Haddad, N.; Haefner, P.; Hageböck, S.; Hajduk, Z.; Hakobyan, H.; Haleem, M.; Haley, J.; Hall, D.; Halladjian, G.; Hallewell, G. D.; Hamacher, K.; Hamal, P.; Hamano, K.; Hamilton, A.; Hamity, G. N.; Hamnett, P. G.; Han, L.; Hanagaki, K.; Hanawa, K.; Hance, M.; Hanke, P.; Hanna, R.; Hansen, J. B.; Hansen, J. D.; Hansen, M. C.; Hansen, P. H.; Hara, K.; Hard, A. S.; Harenberg, T.; Hariri, F.; Harkusha, S.; Harrington, R. D.; Harrison, P. F.; Hartjes, F.; Hasegawa, M.; Hasegawa, S.; Hasegawa, Y.; Hasib, A.; Hassani, S.; Haug, S.; Hauser, R.; Hauswald, L.; Havranek, M.; Hawkes, C. M.; Hawkings, R. J.; Hawkins, A. D.; Hayashi, T.; Hayden, D.; Hays, C. P.; Hays, J. M.; Hayward, H. S.; Haywood, S. J.; Head, S. J.; Heck, T.; Hedberg, V.; Heelan, L.; Heim, S.; Heim, T.; Heinemann, B.; Heinrich, L.; Hejbal, J.; Helary, L.; Hellman, S.; Hellmich, D.; Helsens, C.; Henderson, J.; Henderson, R. C. W.; Heng, Y.; Hengler, C.; Henrichs, A.; Henriques Correia, A. M.; Henrot-Versille, S.; Herbert, G. H.; Hernández Jiménez, Y.; Herrberg-Schubert, R.; Herten, G.; Hertenberger, R.; Hervas, L.; Hesketh, G. G.; Hessey, N. P.; Hetherly, J. W.; Hickling, R.; Higón-Rodriguez, E.; Hill, E.; Hill, J. C.; Hiller, K. H.; Hillier, S. J.; Hinchliffe, I.; Hines, E.; Hinman, R. R.; Hirose, M.; Hirschbuehl, D.; Hobbs, J.; Hod, N.; Hodgkinson, M. C.; Hodgson, P.; Hoecker, A.; Hoeferkamp, M. R.; Hoenig, F.; Hohlfeld, M.; Hohn, D.; Holmes, T. R.; Homann, M.; Hong, T. M.; Hooft van Huysduynen, L.; Hopkins, W. H.; Horii, Y.; Horton, A. J.; Hostachy, J.-Y.; Hou, S.; Hoummada, A.; Howard, J.; Howarth, J.; Hrabovsky, M.; Hristova, I.; Hrivnac, J.; Hryn'ova, T.; Hrynevich, A.; Hsu, C.; Hsu, P. J.; Hsu, S.-C.; Hu, D.; Hu, Q.; Hu, X.; Huang, Y.; Hubacek, Z.; Hubaut, F.; Huegging, F.; Huffman, T. B.; Hughes, E. W.; Hughes, G.; Huhtinen, M.; Hülsing, T. A.; Huseynov, N.; Huston, J.; Huth, J.; Iacobucci, G.; Iakovidis, G.; Ibragimov, I.; Iconomidou-Fayard, L.; Ideal, E.; Idrissi, Z.; Iengo, P.; Igonkina, O.; Iizawa, T.; Ikegami, Y.; Ikematsu, K.; Ikeno, M.; Ilchenko, Y.; Iliadis, D.; Ilic, N.; Ince, T.; Introzzi, G.; Ioannou, P.; Iodice, M.; Iordanidou, K.; Ippolito, V.; Irles Quiles, A.; Isaksson, C.; Ishino, M.; Ishitsuka, M.; Ishmukhametov, R.; Issever, C.; Istin, S.; Iturbe Ponce, J. M.; Iuppa, R.; Ivarsson, J.; Iwanski, W.; Iwasaki, H.; Izen, J. M.; Izzo, V.; Jabbar, S.; Jackson, B.; Jackson, M.; Jackson, P.; Jaekel, M. R.; Jain, V.; Jakobs, K.; Jakobsen, S.; Jakoubek, T.; Jakubek, J.; Jamin, D. O.; Jana, D. K.; Jansen, E.; Jansky, R. W.; Janssen, J.; Janus, M.; Jarlskog, G.; Javadov, N.; Javůrek, T.; Jeanty, L.; Jejelava, J.; Jeng, G.-Y.; Jennens, D.; Jenni, P.; Jentzsch, J.; Jeske, C.; Jézéquel, S.; Ji, H.; Jia, J.; Jiang, Y.; Jiggins, S.; Jimenez Pena, J.; Jin, S.; Jinaru, A.; Jinnouchi, O.; Joergensen, M. D.; Johansson, P.; Johns, K. A.; Jon-And, K.; Jones, G.; Jones, R. W. L.; Jones, T. J.; Jongmanns, J.; Jorge, P. M.; Joshi, K. D.; Jovicevic, J.; Ju, X.; Jung, C. A.; Jussel, P.; Juste Rozas, A.; Kaci, M.; Kaczmarska, A.; Kado, M.; Kagan, H.; Kagan, M.; Kahn, S. J.; Kajomovitz, E.; Kalderon, C. W.; Kama, S.; Kamenshchikov, A.; Kanaya, N.; Kaneti, S.; Kantserov, V. A.; Kanzaki, J.; Kaplan, B.; Kaplan, L. S.; Kapliy, A.; Kar, D.; Karakostas, K.; Karamaoun, A.; Karastathis, N.; Kareem, M. J.; Karnevskiy, M.; Karpov, S. N.; Karpova, Z. M.; Karthik, K.; Kartvelishvili, V.; Karyukhin, A. N.; Kashif, L.; Kass, R. D.; Kastanas, A.; Kataoka, Y.; Kato, C.; Katre, A.; Katzy, J.; Kawagoe, K.; Kawamoto, T.; Kawamura, G.; Kazama, S.; Kazanin, V. F.; Keeler, R.; Kehoe, R.; Keller, J. S.; Kempster, J. J.; Keoshkerian, H.; Kepka, O.; Kerševan, B. P.; Kersten, S.; Keyes, R. A.; Khalil-zada, F.; Khandanyan, H.; Khanov, A.; Kharlamov, A. G.; Khoo, T. J.; Khovanskiy, V.; Khramov, E.; Khubua, J.; Kido, S.; Kim, H. Y.; Kim, S. H.; Kim, Y.; Kimura, N.; Kind, O. M.; King, B. T.; King, M.; King, S. B.; Kirk, J.; Kiryunin, A. E.; Kishimoto, T.; Kisielewska, D.; Kiss, F.; Kiuchi, K.; Kivernyk, O.; Kladiva, E.; Klein, M. H.; Klein, M.; Klein, U.; Kleinknecht, K.; Klimek, P.; Klimentov, A.; Klingenberg, R.; Klinger, J. A.; Klioutchnikova, T.; Kluge, E.-E.; Kluit, P.; Kluth, S.; Knapik, J.; Kneringer, E.; Knoops, E. B. F. G.; Knue, A.; Kobayashi, A.; Kobayashi, D.; Kobayashi, T.; Kobel, M.; Kocian, M.; Kodys, P.; Koffas, T.; Koffeman, E.; Kogan, L. A.; Kohlmann, S.; Kohout, Z.; Kohriki, T.; Koi, T.; Kolanoski, H.; Koletsou, I.; Komar, A. A.; Komori, Y.; Kondo, T.; Kondrashova, N.; Köneke, K.; König, A. C.; Kono, T.; Konoplich, R.; Konstantinidis, N.; Kopeliansky, R.; Koperny, S.; Köpke, L.; Kopp, A. K.; Korcyl, K.; Kordas, K.; Korn, A.; Korol, A. A.; Korolkov, I.; Korolkova, E. V.; Kortner, O.; Kortner, S.; Kosek, T.; Kostyukhin, V. V.; Kotov, V. M.; Kotwal, A.; Kourkoumeli-Charalampidi, A.; Kourkoumelis, C.; Kouskoura, V.; Koutsman, A.; Kowalewski, R.; Kowalski, T. Z.; Kozanecki, W.; Kozhin, A. S.; Kramarenko, V. A.; Kramberger, G.; Krasnopevtsev, D.; Krasny, M. W.; Krasznahorkay, A.; Kraus, J. K.; Kravchenko, A.; Kreiss, S.; Kretz, M.; Kretzschmar, J.; Kreutzfeldt, K.; Krieger, P.; Krizka, K.; Kroeninger, K.; Kroha, H.; Kroll, J.; Kroseberg, J.; Krstic, J.; Kruchonak, U.; Krüger, H.; Krumnack, N.; Kruse, A.; Kruse, M. C.; Kruskal, M.; Kubota, T.; Kucuk, H.; Kuday, S.; Kuehn, S.; Kugel, A.; Kuger, F.; Kuhl, A.; Kuhl, T.; Kukhtin, V.; Kulchitsky, Y.; Kuleshov, S.; Kuna, M.; Kunigo, T.; Kupco, A.; Kurashige, H.; Kurochkin, Y. A.; Kus, V.; Kuwertz, E. S.; Kuze, M.; Kvita, J.; Kwan, T.; Kyriazopoulos, D.; La Rosa, A.; La Rosa Navarro, J. L.; La Rotonda, L.; Lacasta, C.; Lacava, F.; Lacey, J.; Lacker, H.; Lacour, D.; Lacuesta, V. R.; Ladygin, E.; Lafaye, R.; Laforge, B.; Lagouri, T.; Lai, S.; Lambourne, L.; Lammers, S.; Lampen, C. L.; Lampl, W.; Lançon, E.; Landgraf, U.; Landon, M. P. J.; Lang, V. S.; Lange, J. C.; Lankford, A. J.; Lanni, F.; Lantzsch, K.; Lanza, A.; Laplace, S.; Lapoire, C.; Laporte, J. F.; Lari, T.; Lasagni Manghi, F.; Lassnig, M.; Laurelli, P.; Lavrijsen, W.; Law, A. T.; Laycock, P.; Lazovich, T.; Le Dortz, O.; Le Guirriec, E.; Le Menedeu, E.; LeBlanc, M.; LeCompte, T.; Ledroit-Guillon, F.; Lee, C. A.; Lee, S. C.; Lee, L.; Lefebvre, G.; Lefebvre, M.; Legger, F.; Leggett, C.; Lehan, A.; Lehmann Miotto, G.; Lei, X.; Leight, W. A.; Leisos, A.; Leister, A. G.; Leite, M. A. L.; Leitner, R.; Lellouch, D.; Lemmer, B.; Leney, K. J. C.; Lenz, T.; Lenzi, B.; Leone, R.; Leone, S.; Leonidopoulos, C.; Leontsinis, S.; Leroy, C.; Lester, C. G.; Levchenko, M.; Levêque, J.; Levin, D.; Levinson, L. J.; Levy, M.; Lewis, A.; Leyko, A. M.; Leyton, M.; Li, B.; Li, H.; Li, H. L.; Li, L.; Li, L.; Li, S.; Li, Y.; Liang, Z.; Liao, H.; Liberti, B.; Liblong, A.; Lichard, P.; Lie, K.; Liebal, J.; Liebig, W.; Limbach, C.; Limosani, A.; Lin, S. C.; Lin, T. H.; Linde, F.; Lindquist, B. E.; Linnemann, J. T.; Lipeles, E.; Lipniacka, A.; Lisovyi, M.; Liss, T. M.; Lissauer, D.; Lister, A.; Litke, A. M.; Liu, B.; Liu, D.; Liu, H.; Liu, J.; Liu, J. B.; Liu, K.; Liu, L.; Liu, M.; Liu, M.; Liu, Y.; Livan, M.; Lleres, A.; Llorente Merino, J.; Lloyd, S. L.; Lo Sterzo, F.; Lobodzinska, E.; Loch, P.; Lockman, W. S.; Loebinger, F. K.; Loevschall-Jensen, A. E.; Loginov, A.; Lohse, T.; Lohwasser, K.; Lokajicek, M.; Long, B. A.; Long, J. D.; Long, R. E.; Looper, K. A.; Lopes, L.; Lopez Mateos, D.; Lopez Paredes, B.; Lopez Paz, I.; Lorenz, J.; Lorenzo Martinez, N.; Losada, M.; Loscutoff, P.; Lösel, P. J.; Lou, X.; Lounis, A.; Love, J.; Love, P. A.; Lu, N.; Lubatti, H. J.; Luci, C.; Lucotte, A.; Luehring, F.; Lukas, W.; Luminari, L.; Lundberg, O.; Lund-Jensen, B.; Lynn, D.; Lysak, R.; Lytken, E.; Ma, H.; Ma, L. L.; Maccarrone, G.; Macchiolo, A.; Macdonald, C. M.; Maček, B.; Machado Miguens, J.; Macina, D.; Madaffari, D.; Madar, R.; Maddocks, H. J.; Mader, W. F.; Madsen, A.; Maeda, J.; Maeland, S.; Maeno, T.; Maevskiy, A.; Magradze, E.; Mahboubi, K.; Mahlstedt, J.; Maiani, C.; Maidantchik, C.; Maier, A. A.; Maier, T.; Maio, A.; Majewski, S.; Makida, Y.; Makovec, N.; Malaescu, B.; Malecki, Pa.; Maleev, V. P.; Malek, F.; Mallik, U.; Malon, D.; Malone, C.; Maltezos, S.; Malyshev, V. M.; Malyukov, S.; Mamuzic, J.; Mancini, G.; Mandelli, B.; Mandelli, L.; Mandić, I.; Mandrysch, R.; Maneira, J.; Manfredini, A.; Manhaes de Andrade Filho, L.; Manjarres Ramos, J.; Mann, A.; Manousakis-Katsikakis, A.; Mansoulie, B.; Mantifel, R.; Mantoani, M.; Mapelli, L.; March, L.; Marchiori, G.; Marcisovsky, M.; Marino, C. P.; Marjanovic, M.; Marley, D. E.; Marroquim, F.; Marsden, S. P.; Marshall, Z.; Marti, L. F.; Marti-Garcia, S.; Martin, B.; Martin, T. A.; Martin, V. J.; Martin dit Latour, B.; Martinez, M.; Martin-Haugh, S.; Martoiu, V. S.; Martyniuk, A. C.; Marx, M.; Marzano, F.; Marzin, A.; Masetti, L.; Mashimo, T.; Mashinistov, R.; Masik, J.; Maslennikov, A. L.; Massa, I.; Massa, L.; Massol, N.; Mastrandrea, P.; Mastroberardino, A.; Masubuchi, T.; Mättig, P.; Mattmann, J.; Maurer, J.; Maxfield, S. J.; Maximov, D. A.; Mazini, R.; Mazza, S. M.; Mazzaferro, L.; Mc Goldrick, G.; Mc Kee, S. P.; McCarn, A.; McCarthy, R. L.; McCarthy, T. G.; McCubbin, N. A.; McFarlane, K. W.; Mcfayden, J. A.; Mchedlidze, G.; McMahon, S. J.; McPherson, R. A.; Medinnis, M.; Meehan, S.; Mehlhase, S.; Mehta, A.; Meier, K.; Meineck, C.; Meirose, B.; Mellado Garcia, B. R.; Meloni, F.; Mengarelli, A.; Menke, S.; Meoni, E.; Mercurio, K. M.; Mergelmeyer, S.; Mermod, P.; Merola, L.; Meroni, C.; Merritt, F. S.; Messina, A.; Metcalfe, J.; Mete, A. S.; Meyer, C.; Meyer, C.; Meyer, J.-P.; Meyer, J.; Meyer Zu Theenhausen, H.; Middleton, R. P.; Miglioranzi, S.; Mijović, L.; Mikenberg, G.; Mikestikova, M.; Mikuž, M.; Milesi, M.; Milic, A.; Miller, D. W.; Mills, C.; Milov, A.; Milstead, D. A.; Minaenko, A. A.; Minami, Y.; Minashvili, I. A.; Mincer, A. I.; Mindur, B.; Mineev, M.; Ming, Y.; Mir, L. M.; Mitani, T.; Mitrevski, J.; Mitsou, V. A.; Miucci, A.; Miyagawa, P. S.; Mjörnmark, J. U.; Moa, T.; Mochizuki, K.; Mohapatra, S.; Mohr, W.; Molander, S.; Moles-Valls, R.; Mönig, K.; Monini, C.; Monk, J.; Monnier, E.; Montejo Berlingen, J.; Monticelli, F.; Monzani, S.; Moore, R. W.; Morange, N.; Moreno, D.; Moreno Llácer, M.; Morettini, P.; Morgenstern, M.; Mori, D.; Morii, M.; Morinaga, M.; Morisbak, V.; Moritz, S.; Morley, A. K.; Mornacchi, G.; Morris, J. D.; Mortensen, S. S.; Morton, A.; Morvaj, L.; Mosidze, M.; Moss, J.; Motohashi, K.; Mount, R.; Mountricha, E.; Mouraviev, S. V.; Moyse, E. J. W.; Muanza, S.; Mudd, R. D.; Mueller, F.; Mueller, J.; Mueller, R. S. P.; Mueller, T.; Muenstermann, D.; Mullen, P.; Mullier, G. A.; Murillo Quijada, J. A.; Murray, W. J.; Musheghyan, H.; Musto, E.; Myagkov, A. G.; Myska, M.; Nachman, B. P.; Nackenhorst, O.; Nadal, J.; Nagai, K.; Nagai, R.; Nagai, Y.; Nagano, K.; Nagarkar, A.; Nagasaka, Y.; Nagata, K.; Nagel, M.; Nagy, E.; Nairz, A. M.; Nakahama, Y.; Nakamura, K.; Nakamura, T.; Nakano, I.; Namasivayam, H.; Naranjo Garcia, R. F.; Narayan, R.; Naumann, T.; Navarro, G.; Nayyar, R.; Neal, H. A.; Nechaeva, P. Yu.; Neep, T. J.; Nef, P. D.; Negri, A.; Negrini, M.; Nektarijevic, S.; Nellist, C.; Nelson, A.; Nemecek, S.; Nemethy, P.; Nepomuceno, A. A.; Nessi, M.; Neubauer, M. S.; Neumann, M.; Neves, R. M.; Nevski, P.; Newman, P. R.; Nguyen, D. H.; Nickerson, R. B.; Nicolaidou, R.; Nicquevert, B.; Nielsen, J.; Nikiforou, N.; Nikiforov, A.; Nikolaenko, V.; Nikolic-Audit, I.; Nikolopoulos, K.; Nilsen, J. K.; Nilsson, P.; Ninomiya, Y.; Nisati, A.; Nisius, R.; Nobe, T.; Nomachi, M.; Nomidis, I.; Nooney, T.; Norberg, S.; Nordberg, M.; Novgorodova, O.; Nowak, S.; Nozaki, M.; Nozka, L.; Ntekas, K.; Nunes Hanninger, G.; Nunnemann, T.; Nurse, E.; Nuti, F.; O'Brien, B. J.; O'grady, F.; O'Neil, D. C.; O'Shea, V.; Oakham, F. G.; Oberlack, H.; Obermann, T.; Ocariz, J.; Ochi, A.; Ochoa, I.; Ochoa-Ricoux, J. P.; Oda, S.; Odaka, S.; Ogren, H.; Oh, A.; Oh, S. H.; Ohm, C. C.; Ohman, H.; Oide, H.; Okamura, W.; Okawa, H.; Okumura, Y.; Okuyama, T.; Olariu, A.; Olivares Pino, S. A.; Oliveira Damazio, D.; Oliver Garcia, E.; Olszewski, A.; Olszowska, J.; Onofre, A.; Onyisi, P. U. E.; Oram, C. J.; Oreglia, M. J.; Oren, Y.; Orestano, D.; Orlando, N.; Oropeza Barrera, C.; Orr, R. S.; Osculati, B.; Ospanov, R.; Otero y Garzon, G.; Otono, H.; Ouchrif, M.; Ouellette, E. A.; Ould-Saada, F.; Ouraou, A.; Oussoren, K. P.; Ouyang, Q.; Ovcharova, A.; Owen, M.; Owen, R. E.; Ozcan, V. E.; Ozturk, N.; Pachal, K.; Pacheco Pages, A.; Padilla Aranda, C.; Pagáčová, M.; Pagan Griso, S.; Paganis, E.; Paige, F.; Pais, P.; Pajchel, K.; Palacino, G.; Palestini, S.; Palka, M.; Pallin, D.; Palma, A.; Pan, Y. B.; Panagiotopoulou, E.; Pandini, C. E.; Panduro Vazquez, J. G.; Pani, P.; Panitkin, S.; Pantea, D.; Paolozzi, L.; Papadopoulou, Th. D.; Papageorgiou, K.; Paramonov, A.; Paredes Hernandez, D.; Parker, M. A.; Parker, K. A.; Parodi, F.; Parsons, J. A.; Parzefall, U.; Pasqualucci, E.; Passaggio, S.; Pastore, F.; Pastore, Fr.; Pásztor, G.; Pataraia, S.; Patel, N. D.; Pater, J. R.; Pauly, T.; Pearce, J.; Pearson, B.; Pedersen, L. E.; Pedersen, M.; Pedraza Lopez, S.; Pedro, R.; Peleganchuk, S. V.; Pelikan, D.; Penc, O.; Peng, C.; Peng, H.; Penning, B.; Penwell, J.; Perepelitsa, D. V.; Perez Codina, E.; Pérez García-Estañ, M. T.; Perini, L.; Pernegger, H.; Perrella, S.; Peschke, R.; Peshekhonov, V. D.; Peters, K.; Peters, R. F. Y.; Petersen, B. A.; Petersen, T. C.; Petit, E.; Petridis, A.; Petridou, C.; Petroff, P.; Petrolo, E.; Petrucci, F.; Pettersson, N. E.; Pezoa, R.; Phillips, P. W.; Piacquadio, G.; Pianori, E.; Picazio, A.; Piccaro, E.; Piccinini, M.; Pickering, M. A.; Piegaia, R.; Pignotti, D. T.; Pilcher, J. E.; Pilkington, A. D.; Pina, J.; Pinamonti, M.; Pinfold, J. L.; Pingel, A.; Pinto, B.; Pires, S.; Pirumov, H.; Pitt, M.; Pizio, C.; Plazak, L.; Pleier, M.-A.; Pleskot, V.; Plotnikova, E.; Plucinski, P.; Pluth, D.; Poettgen, R.; Poggioli, L.; Pohl, D.; Polesello, G.; Poley, A.; Policicchio, A.; Polifka, R.; Polini, A.; Pollard, C. S.; Polychronakos, V.; Pommès, K.; Pontecorvo, L.; Pope, B. G.; Popeneciu, G. A.; Popovic, D. S.; Poppleton, A.; Pospisil, S.; Potamianos, K.; Potrap, I. N.; Potter, C. J.; Potter, C. T.; Poulard, G.; Poveda, J.; Pozdnyakov, V.; Pralavorio, P.; Pranko, A.; Prasad, S.; Prell, S.; Price, D.; Price, L. E.; Primavera, M.; Prince, S.; Proissl, M.; Prokofiev, K.; Prokoshin, F.; Protopapadaki, E.; Protopopescu, S.; Proudfoot, J.; Przybycien, M.; Ptacek, E.; Puddu, D.; Pueschel, E.; Puldon, D.; Purohit, M.; Puzo, P.; Qian, J.; Qin, G.; Qin, Y.; Quadt, A.; Quarrie, D. R.; Quayle, W. B.; Queitsch-Maitland, M.; Quilty, D.; Raddum, S.; Radeka, V.; Radescu, V.; Radhakrishnan, S. K.; Radloff, P.; Rados, P.; Ragusa, F.; Rahal, G.; Rajagopalan, S.; Rammensee, M.; Rangel-Smith, C.; Rauscher, F.; Rave, S.; Ravenscroft, T.; Raymond, M.; Read, A. L.; Readioff, N. P.; Rebuzzi, D. M.; Redelbach, A.; Redlinger, G.; Reece, R.; Reeves, K.; Rehnisch, L.; Reisin, H.; Relich, M.; Rembser, C.; Ren, H.; Renaud, A.; Rescigno, M.; Resconi, S.; Rezanova, O. L.; Reznicek, P.; Rezvani, R.; Richter, R.; Richter, S.; Richter-Was, E.; Ricken, O.; Ridel, M.; Rieck, P.; Riegel, C. J.; Rieger, J.; Rijssenbeek, M.; Rimoldi, A.; Rinaldi, L.; Ristić, B.; Ritsch, E.; Riu, I.; Rizatdinova, F.; Rizvi, E.; Robertson, S. H.; Robichaud-Veronneau, A.; Robinson, D.; Robinson, J. E. M.; Robson, A.; Roda, C.; Roe, S.; Røhne, O.; Rolli, S.; Romaniouk, A.; Romano, M.; Romano Saez, S. M.; Romero Adam, E.; Rompotis, N.; Ronzani, M.; Roos, L.; Ros, E.; Rosati, S.; Rosbach, K.; Rose, P.; Rosendahl, P. L.; Rosenthal, O.; Rossetti, V.; Rossi, E.; Rossi, L. P.; Rosten, R.; Rotaru, M.; Roth, I.; Rothberg, J.; Rousseau, D.; Royon, C. R.; Rozanov, A.; Rozen, Y.; Ruan, X.; Rubbo, F.; Rubinskiy, I.; Rud, V. I.; Rudolph, C.; Rudolph, M. S.; Rühr, F.; Ruiz-Martinez, A.; Rurikova, Z.; Rusakovich, N. A.; Ruschke, A.; Russell, H. L.; Rutherfoord, J. P.; Ruthmann, N.; Ryabov, Y. F.; Rybar, M.; Rybkin, G.; Ryder, N. C.; Saavedra, A. F.; Sabato, G.; Sacerdoti, S.; Saddique, A.; Sadrozinski, H. F.-W.; Sadykov, R.; Safai Tehrani, F.; Sahinsoy, M.; Saimpert, M.; Saito, T.; Sakamoto, H.; Sakurai, Y.; Salamanna, G.; Salamon, A.; Saleem, M.; Salek, D.; Sales De Bruin, P. H.; Salihagic, D.; Salnikov, A.; Salt, J.; Salvatore, D.; Salvatore, F.; Salvucci, A.; Salzburger, A.; Sammel, D.; Sampsonidis, D.; Sanchez, A.; Sánchez, J.; Sanchez Martinez, V.; Sandaker, H.; Sandbach, R. L.; Sander, H. G.; Sanders, M. P.; Sandhoff, M.; Sandoval, C.; Sandstroem, R.; Sankey, D. P. C.; Sannino, M.; Sansoni, A.; Santoni, C.; Santonico, R.; Santos, H.; Santoyo Castillo, I.; Sapp, K.; Sapronov, A.; Saraiva, J. G.; Sarrazin, B.; Sasaki, O.; Sasaki, Y.; Sato, K.; Sauvage, G.; Sauvan, E.; Savage, G.; Savard, P.; Sawyer, C.; Sawyer, L.; Saxon, J.; Sbarra, C.; Sbrizzi, A.; Scanlon, T.; Scannicchio, D. A.; Scarcella, M.; Scarfone, V.; Schaarschmidt, J.; Schacht, P.; Schaefer, D.; Schaefer, R.; Schaeffer, J.; Schaepe, S.; Schaetzel, S.; Schäfer, U.; Schaffer, A. C.; Schaile, D.; Schamberger, R. D.; Scharf, V.; Schegelsky, V. A.; Scheirich, D.; Schernau, M.; Schiavi, C.; Schillo, C.; Schioppa, M.; Schlenker, S.; Schmidt, E.; Schmieden, K.; Schmitt, C.; Schmitt, S.; Schmitt, S.; Schneider, B.; Schnellbach, Y. J.; Schnoor, U.; Schoeffel, L.; Schoening, A.; Schoenrock, B. D.; Schopf, E.; Schorlemmer, A. L. S.; Schott, M.; Schouten, D.; Schovancova, J.; Schramm, S.; Schreyer, M.; Schroeder, C.; Schuh, N.; Schultens, M. J.; Schultz-Coulon, H.-C.; Schulz, H.; Schumacher, M.; Schumm, B. A.; Schune, Ph.; Schwanenberger, C.; Schwartzman, A.; Schwarz, T. A.; Schwegler, Ph.; Schweiger, H.; Schwemling, Ph.; Schwienhorst, R.; Schwindling, J.; Schwindt, T.; Sciacca, F. G.; Scifo, E.; Sciolla, G.; Scuri, F.; Scutti, F.; Searcy, J.; Sedov, G.; Sedykh, E.; Seema, P.; Seidel, S. C.; Seiden, A.; Seifert, F.; Seixas, J. M.; Sekhniaidze, G.; Sekhon, K.; Sekula, S. J.; Seliverstov, D. M.; Semprini-Cesari, N.; Serfon, C.; Serin, L.; Serkin, L.; Serre, T.; Sessa, M.; Seuster, R.; Severini, H.; Sfiligoj, T.; Sforza, F.; Sfyrla, A.; Shabalina, E.; Shamim, M.; Shan, L. Y.; Shang, R.; Shank, J. T.; Shapiro, M.; Shatalov, P. B.; Shaw, K.; Shaw, S. M.; Shcherbakova, A.; Shehu, C. Y.; Sherwood, P.; Shi, L.; Shimizu, S.; Shimmin, C. O.; Shimojima, M.; Shiyakova, M.; Shmeleva, A.; Shoaleh Saadi, D.; Shochet, M. J.; Shojaii, S.; Shrestha, S.; Shulga, E.; Shupe, M. A.; Shushkevich, S.; Sicho, P.; Sidebo, P. E.; Sidiropoulou, O.; Sidorov, D.; Sidoti, A.; Siegert, F.; Sijacki, Dj.; Silva, J.; Silver, Y.; Silverstein, S. B.; Simak, V.; Simard, O.; Simic, Lj.; Simion, S.; Simioni, E.; Simmons, B.; Simon, D.; Simoniello, R.; Sinervo, P.; Sinev, N. B.; Siragusa, G.; Sisakyan, A. N.; Sivoklokov, S. Yu.; Sjölin, J.; Sjursen, T. B.; Skinner, M. B.; Skottowe, H. P.; Skubic, P.; Slater, M.; Slavicek, T.; Slawinska, M.; Sliwa, K.; Smakhtin, V.; Smart, B. H.; Smestad, L.; Smirnov, S. Yu.; Smirnov, Y.; Smirnova, L. N.; Smirnova, O.; Smith, M. N. K.; Smith, R. W.; Smizanska, M.; Smolek, K.; Snesarev, A. A.; Snidero, G.; Snyder, S.; Sobie, R.; Socher, F.; Soffer, A.; Soh, D. A.; Solans, C. A.; Solar, M.; Solc, J.; Soldatov, E. Yu.; Soldevila, U.; Solodkov, A. A.; Soloshenko, A.; Solovyanov, O. V.; Solovyev, V.; Sommer, P.; Song, H. Y.; Soni, N.; Sood, A.; Sopczak, A.; Sopko, B.; Sopko, V.; Sorin, V.; Sosa, D.; Sosebee, M.; Sotiropoulou, C. L.; Soualah, R.; Soukharev, A. M.; South, D.; Sowden, B. C.; Spagnolo, S.; Spalla, M.; Spanò, F.; Spearman, W. R.; Sperlich, D.; Spettel, F.; Spighi, R.; Spigo, G.; Spiller, L. A.; Spousta, M.; Spreitzer, T.; St. Denis, R. D.; Staerz, S.; Stahlman, J.; Stamen, R.; Stamm, S.; Stanecka, E.; Stanescu, C.; Stanescu-Bellu, M.; Stanitzki, M. M.; Stapnes, S.; Starchenko, E. A.; Stark, J.; Staroba, P.; Starovoitov, P.; Staszewski, R.; Stavina, P.; Steinberg, P.; Stelzer, B.; Stelzer, H. J.; Stelzer-Chilton, O.; Stenzel, H.; Stewart, G. A.; Stillings, J. A.; Stockton, M. C.; Stoebe, M.; Stoicea, G.; Stolte, P.; Stonjek, S.; Stradling, A. R.; Straessner, A.; Stramaglia, M. E.; Strandberg, J.; Strandberg, S.; Strandlie, A.; Strauss, E.; Strauss, M.; Strizenec, P.; Ströhmer, R.; Strom, D. M.; Stroynowski, R.; Strubig, A.; Stucci, S. A.; Stugu, B.; Styles, N. A.; Su, D.; Su, J.; Subramaniam, R.; Succurro, A.; Sugaya, Y.; Suhr, C.; Suk, M.; Sulin, V. V.; Sultansoy, S.; Sumida, T.; Sun, S.; Sun, X.; Sundermann, J. E.; Suruliz, K.; Susinno, G.; Sutton, M. R.; Suzuki, S.; Svatos, M.; Swiatlowski, M.; Sykora, I.; Sykora, T.; Ta, D.; Taccini, C.; Tackmann, K.; Taenzer, J.; Taffard, A.; Tafirout, R.; Taiblum, N.; Takai, H.; Takashima, R.; Takeda, H.; Takeshita, T.; Takubo, Y.; Talby, M.; Talyshev, A. A.; Tam, J. Y. C.; Tan, K. G.; Tanaka, J.; Tanaka, R.; Tanaka, S.; Tannenwald, B. B.; Tannoury, N.; Tapprogge, S.; Tarem, S.; Tarrade, F.; Tartarelli, G. F.; Tas, P.; Tasevsky, M.; Tashiro, T.; Tassi, E.; Tavares Delgado, A.; Tayalati, Y.; Taylor, F. E.; Taylor, G. N.; Taylor, W.; Teischinger, F. A.; Teixeira Dias Castanheira, M.; Teixeira-Dias, P.; Temming, K. K.; Ten Kate, H.; Teng, P. K.; Teoh, J. J.; Tepel, F.; Terada, S.; Terashi, K.; Terron, J.; Terzo, S.; Testa, M.; Teuscher, R. J.; Theveneaux-Pelzer, T.; Thomas, J. P.; Thomas-Wilsker, J.; Thompson, E. N.; Thompson, P. D.; Thompson, R. J.; Thompson, A. S.; Thomsen, L. A.; Thomson, E.; Thomson, M.; Thun, R. P.; Tibbetts, M. J.; Ticse Torres, R. E.; Tikhomirov, V. O.; Tikhonov, Yu. A.; Timoshenko, S.; Tiouchichine, E.; Tipton, P.; Tisserant, S.; Todome, K.; Todorov, T.; Todorova-Nova, S.; Tojo, J.; Tokár, S.; Tokushuku, K.; Tollefson, K.; Tolley, E.; Tomlinson, L.; Tomoto, M.; Tompkins, L.; Toms, K.; Torrence, E.; Torres, H.; Torró Pastor, E.; Toth, J.; Touchard, F.; Tovey, D. R.; Trefzger, T.; Tremblet, L.; Tricoli, A.; Trigger, I. M.; Trincaz-Duvoid, S.; Tripiana, M. F.; Trischuk, W.; Trocmé, B.; Troncon, C.; Trottier-McDonald, M.; Trovatelli, M.; True, P.; Truong, L.; Trzebinski, M.; Trzupek, A.; Tsarouchas, C.; Tseng, J. C.-L.; Tsiareshka, P. V.; Tsionou, D.; Tsipolitis, G.; Tsirintanis, N.; Tsiskaridze, S.; Tsiskaridze, V.; Tskhadadze, E. G.; Tsukerman, I. I.; Tsulaia, V.; Tsuno, S.; Tsybychev, D.; Tudorache, A.; Tudorache, V.; Tuna, A. N.; Tupputi, S. A.; Turchikhin, S.; Turecek, D.; Turra, R.; Turvey, A. J.; Tuts, P. M.; Tykhonov, A.; Tylmad, M.; Tyndel, M.; Ueda, I.; Ueno, R.; Ughetto, M.; Ugland, M.; Ukegawa, F.; Unal, G.; Undrus, A.; Unel, G.; Ungaro, F. C.; Unno, Y.; Unverdorben, C.; Urban, J.; Urquijo, P.; Urrejola, P.; Usai, G.; Usanova, A.; Vacavant, L.; Vacek, V.; Vachon, B.; Valderanis, C.; Valencic, N.; Valentinetti, S.; Valero, A.; Valery, L.; Valkar, S.; Valladolid Gallego, E.; Vallecorsa, S.; Valls Ferrer, J. A.; Van Den Wollenberg, W.; Van Der Deijl, P. C.; van der Geer, R.; van der Graaf, H.; Van Der Leeuw, R.; van Eldik, N.; van Gemmeren, P.; Van Nieuwkoop, J.; van Vulpen, I.; van Woerden, M. C.; Vanadia, M.; Vandelli, W.; Vanguri, R.; Vaniachine, A.; Vannucci, F.; Vardanyan, G.; Vari, R.; Varnes, E. W.; Varol, T.; Varouchas, D.; Vartapetian, A.; Varvell, K. E.; Vazeille, F.; Vazquez Schroeder, T.; Veatch, J.; Veloce, L. M.; Veloso, F.; Velz, T.; Veneziano, S.; Ventura, A.; Ventura, D.; Venturi, M.; Venturi, N.; Venturini, A.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J. C.; Vest, A.; Vetterli, M. C.; Viazlo, O.; Vichou, I.; Vickey, T.; Vickey Boeriu, O. E.; Viehhauser, G. H. A.; Viel, S.; Vigne, R.; Villa, M.; Villaplana Perez, M.; Vilucchi, E.; Vincter, M. G.; Vinogradov, V. B.; Vivarelli, I.; Vives Vaque, F.; Vlachos, S.; Vladoiu, D.; Vlasak, M.; Vogel, M.; Vokac, P.; Volpi, G.; Volpi, M.; von der Schmitt, H.; von Radziewski, H.; von Toerne, E.; Vorobel, V.; Vorobev, K.; Vos, M.; Voss, R.; Vossebeld, J. H.; Vranjes, N.; Vranjes Milosavljevic, M.; Vrba, V.; Vreeswijk, M.; Vuillermet, R.; Vukotic, I.; Vykydal, Z.; Wagner, P.; Wagner, W.; Wahlberg, H.; Wahrmund, S.; Wakabayashi, J.; Walder, J.; Walker, R.; Walkowiak, W.; Wang, C.; Wang, F.; Wang, H.; Wang, H.; Wang, J.; Wang, J.; Wang, K.; Wang, R.; Wang, S. M.; Wang, T.; Wang, X.; Wanotayaroj, C.; Warburton, A.; Ward, C. P.; Wardrope, D. R.; Washbrook, A.; Wasicki, C.; Watkins, P. M.; Watson, A. T.; Watson, I. J.; Watson, M. F.; Watts, G.; Watts, S.; Waugh, B. M.; Webb, S.; Weber, M. S.; Weber, S. W.; Webster, J. S.; Weidberg, A. R.; Weinert, B.; Weingarten, J.; Weiser, C.; Weits, H.; Wells, P. S.; Wenaus, T.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M.; Werner, P.; Wessels, M.; Wetter, J.; Whalen, K.; Wharton, A. M.; White, A.; White, M. J.; White, R.; White, S.; Whiteson, D.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wienemann, P.; Wiglesworth, C.; Wiik-Fuchs, L. A. M.; Wildauer, A.; Wilkens, H. G.; Williams, H. H.; Williams, S.; Willis, C.; Willocq, S.; Wilson, A.; Wilson, J. A.; Wingerter-Seez, I.; Winklmeier, F.; Winter, B. T.; Wittgen, M.; Wittkowski, J.; Wollstadt, S. J.; Wolter, M. W.; Wolters, H.; Wosiek, B. K.; Wotschack, J.; Woudstra, M. J.; Wozniak, K. W.; Wu, M.; Wu, M.; Wu, S. L.; Wu, X.; Wu, Y.; Wyatt, T. R.; Wynne, B. M.; Xella, S.; Xu, D.; Xu, L.; Yabsley, B.; Yacoob, S.; Yakabe, R.; Yamada, M.; Yamaguchi, Y.; Yamamoto, A.; Yamamoto, S.; Yamanaka, T.; Yamauchi, K.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, H.; Yang, Y.; Yao, W.-M.; Yasu, Y.; Yatsenko, E.; Yau Wong, K. H.; Ye, J.; Ye, S.; Yeletskikh, I.; Yen, A. L.; Yildirim, E.; Yorita, K.; Yoshida, R.; Yoshihara, K.; Young, C.; Young, C. J. S.; Youssef, S.; Yu, D. R.; Yu, J.; Yu, J. M.; Yu, J.; Yuan, L.; Yuen, S. P. Y.; Yurkewicz, A.; Yusuff, I.; Zabinski, B.; Zaidan, R.; Zaitsev, A. M.; Zalieckas, J.; Zaman, A.; Zambito, S.; Zanello, L.; Zanzi, D.; Zeitnitz, C.; Zeman, M.; Zemla, A.; Zengel, K.; Zenin, O.; Ženiš, T.; Zerwas, D.; Zhang, D.; Zhang, F.; Zhang, H.; Zhang, J.; Zhang, L.; Zhang, R.; Zhang, X.; Zhang, Z.; Zhao, X.; Zhao, Y.; Zhao, Z.; Zhemchugov, A.; Zhong, J.; Zhou, B.; Zhou, C.; Zhou, L.; Zhou, L.; Zhou, N.; Zhu, C. G.; Zhu, H.; Zhu, J.; Zhu, Y.; Zhuang, X.; Zhukov, K.; Zibell, A.; Zieminska, D.; Zimine, N. I.; Zimmermann, C.; Zimmermann, S.; Zinonos, Z.; Zinser, M.; Ziolkowski, M.; Živković, L.; Zobernig, G.; Zoccoli, A.; zur Nedden, M.; Zurzolo, G.; Zwalinski, L.

    2015-09-01

    Many extensions of the Standard Model predict the existence of charged heavy long-lived particles, such as R-hadrons or charginos. These particles, if produced at the Large Hadron Collider, should be moving non-relativistically and are therefore identifiable through the measurement of an anomalously large specific energy loss in the ATLAS pixel detector. Measuring heavy long-lived particles through their track parameters in the vicinity of the interaction vertex provides sensitivity to metastable particles with lifetimes from 0.6 ns to 30 ns. A search for such particles with the ATLAS detector at the Large Hadron Collider is presented, based on a data sample corresponding to an integrated luminosity of fb of pp collisions at TeV. No significant deviation from the Standard Model background expectation is observed, and lifetime-dependent upper limits on R-hadrons and chargino production are set. Gluino R-hadrons with 10 ns lifetime and masses up to 1185 GeV are excluded at 95 confidence level, and so are charginos with 15 ns lifetime and masses up to 482 GeV.

  11. Validation of LC/MS electrospray ionisation method for the estimation of ursodiol in human plasma and its application in bioequivalence study.

    PubMed

    Sundd Singh, Sonu; Shah, Hiten; Gupta, Sapna; Jain, Manish; Sharma, Kuldeep; Patel, Harshvardhan; Shah, Bhavin; Thakkar, Purav; Patel, Nimesh; Shah, Ruchy; Bhushan Lohary, Braj

    2004-12-01

    A novel High Performance Liquid Chromatography-electrospray mass spectrometric method has been developed for the estimation of Ursodiol (Ursodeoxycholic acid)--a bile acid, in human plasma using Ornidazole as internal standard. The methodology involved solid phase extraction of the analyte from human plasma matrix. The chromatographic separation was achieved within seven minutes by an isocratic mobile phase containing 1.0 mM ammonium acetate and Acetonitrile (65:35, v/v), flowing through XTerra MS C18, 100 x 2.1, 3.5 microm analytical column, at a flow rate of 0.2 ml/min. Ion signals were measured in negative mode for Ursodiol and internal standard at m/z 391.3 and 278.1, respectively. A detailed validation of the method was performed as per USFDA guidelines and the standard curves were found to be linear in the range 50.0 ng/ml to 3000.0 ng/ml with the mean correlation coefficient more than 0.99. The absolute recovery was more than 54.90% for Ursodiol and 76.51% for internal standard. Ursodiol was stable for sixty-nine days at -70 degrees C and for eight hours at ambient temperature. After extraction from plasma, the reconstituted samples of Ursodiol were stable in autosampler at 10 degrees C for forty-eight hours. Upon subjecting to three freeze thaw cycles, there was no change in the recovery of the analyte. The integrity of the plasma samples remained unaffected even upon four-fold dilution with drug free human plasma. The method was simple, specific, sensitive, precise, accurate and suitable for bioequivalence and pharmacokinetic studies. It was successfully applied to the pilot bioequivalence study of Ursodiol in male human subjects. PMID:15689031

  12. Identification and typing of the emerging pathogen Candida auris by matrix-assisted laser desorption ionisation time of flight mass spectrometry.

    PubMed

    Girard, Victoria; Mailler, Sandrine; Chetry, Marion; Vidal, Céline; Durand, Géraldine; van Belkum, Alex; Colombo, Arnaldo L; Hagen, Ferry; Meis, Jacques F; Chowdhary, Anuradha

    2016-08-01

    Candida auris is an emerging antifungal resistant yeast species causing nosocomial and invasive infections, emphasising the need of improved diagnostics and epidemiological typing methods. We show that MALDI-TOF VITEK-MS followed by amplified length polymorphisms allows for accurate species identification and subsequent epidemiological characterisation of strains encountered during potential outbreaks. PMID:27292939

  13. Validation of a method for the analysis of quinolones residues in bovine muscle by liquid chromatography with electrospray ionisation tandem mass spectrometry detection.

    PubMed

    Rubies, A; Vaquerizo, R; Centrich, F; Compañó, R; Granados, M; Prat, M D

    2007-04-15

    A liquid chromatography-tandem mass spectrometry method for the determination and confirmation of nine quinolones was optimised and validated according to Commission Decision 2002/657/EC. Analytes were extracted from veal muscle with water and extracts purified with 96-well plates Oasis HLB cartridges. Separation was carried out in a silica-based C(18) column (50mmx2.1mm) with mobile phases consisting of water/acetonitrile mixtures containing acetic acid. Linear calibration curves in the ranges 4-400 and 50-800ngg(-1), with correlation coefficients at least 0.995, were obtained for all the analytes. At concentration levels above 10ngg(-1), quantification errors were lower than 10% and repeatability and within-laboratory reproducibility standard deviations below 6% and 10%, respectively. Decision limits and detection capabilities are reported. PMID:19071613

  14. Numerical simulation of microwave amplification in a plasma channel produced in a gas via multiphoton ionisation by a femtosecond laser pulse

    SciTech Connect

    Bogatskaya, A V; Popov, A M; Volkova, E A

    2014-12-31

    This paper examines the evolution of a nonequilibrium plasma channel produced in xenon by a femtosecond KrF laser pulse. We demonstrate that such a channel can be used to amplify microwave pulses over times of the order of the relaxation time of the photoelectron energy spectrum in xenon. Using the slowly varying amplitude approximation, we analyse the propagation and amplification of an rf pulse in a plasma channel, in particular when the rf field influences the electron energy distribution function in the plasma. (interaction of laser radiation with matter. laser plasma)

  15. The calibration of plane parallel ionisation chambers for the measurement of absorbed dose in electron beams of low to medium energies. Part 1: the NACP chamber.

    PubMed

    Cross, P; Freeman, N

    1996-09-01

    A study was made of calibrating the NACP plane parallel chamber in electron beams from linear accelerators of a different manufacture with energies, Ep,o' from 4.4 to 19.1 MeV, and also in 4 and 6 MV photon beams as well as a cobalt60 beam. The photon beam measurements were both IN-AIR and IN-PHANTOM. With the exception of the lowest energy electron beam (nominal 5 MeV), the ND values from measurements in the electron beams were within +/- 1% of the average value from the three different methods according to the AAPM TG 39 protocol. The preferred method of calibration of an electron chamber is of course in an electron beam at R100 in water. This can still be done in medium energy electron beams (nominal 7 to 14 MeV) for the NACP chamber with the same degree of accuracy and precision as with AAPM TG 39 methodology. Alternatively the traditional cobalt-60 calibration beam can be replaced by a low energy (4-6MV) photon beam for in-phantom calibrations at 50 mm depth, giving comparable results, and with no more uncertainties than those obtained in electron beams. PMID:8936730

  16. Time-resolved dosimetric verification of respiratory-gated radiotherapy exposures using a high-resolution 2D ionisation chamber array

    NASA Astrophysics Data System (ADS)

    King, R. B.; Agnew, C. E.; O’Connell, B. F.; Prise, K. M.; Hounsell, A. R.; McGarry, C. K.

    2016-08-01

    The aim of this work was to track and verify the delivery of respiratory-gated irradiations, performed with three versions of TrueBeam linac, using a novel phantom arrangement that combined the OCTAVIUS® SRS 1000 array with a moving platform. The platform was programmed to generate sinusoidal motion of the array. This motion was tracked using the real-time position management (RPM) system and four amplitude gating options were employed to interrupt MV beam delivery when the platform was not located within set limits. Time-resolved spatial information extracted from analysis of x-ray fluences measured by the array was compared to the programmed motion of the platform and to the trace recorded by the RPM system during the delivery of the x-ray field. Temporal data recorded by the phantom and the RPM system were validated against trajectory log files, recorded by the linac during the irradiation, as well as oscilloscope waveforms recorded from the linac target signal. Gamma analysis was employed to compare time-integrated 2D x-ray dose fluences with theoretical fluences derived from the probability density function for each of the gating settings applied, where gamma criteria of 2%/2 mm, 1%/1 mm and 0.5%/0.5 mm were used to evaluate the limitations of the RPM system. Excellent agreement was observed in the analysis of spatial information extracted from the SRS 1000 array measurements. Comparisons of the average platform position with the expected position indicated absolute deviations of  <0.5 mm for all four gating settings. Differences were observed when comparing time-resolved beam-on data stored in the RPM files and trajectory logs to the true target signal waveforms. Trajectory log files underestimated the cycle time between consecutive beam-on windows by 10.0  ±  0.8 ms. All measured fluences achieved 100% pass-rates using gamma criteria of 2%/2 mm and 50% of the fluences achieved pass-rates  >90% when criteria of 0.5%/0.5 mm were used. Results using this novel phantom arrangement indicate that the RPM system is capable of accurately gating x-ray exposure during the delivery of a fixed-field treatment beam.

  17. A fast ionised wind in a star-forming quasar system at z ~ 1.5 resolved through adaptive optics assisted near-infrared data

    NASA Astrophysics Data System (ADS)

    Brusa, M.; Perna, M.; Cresci, G.; Schramm, M.; Delvecchio, I.; Lanzuisi, G.; Mainieri, V.; Mignoli, M.; Zamorani, G.; Berta, S.; Bongiorno, A.; Comastri, A.; Fiore, F.; Kakkad, D.; Marconi, A.; Rosario, D.; Contini, T.; Lamareille, F.

    2016-04-01

    Aims: Outflow winds are invoked in co-evolutionary models to link the growth of SMBH and galaxies through feedback phenomena, and from the analysis of both galaxies and active galactic nuclei (AGN) samples at z ~ 1-3, it is becoming clear that powerful outflows may be very common in AGN hosts. High-resolution and high S/N observations are needed to uncover the physical properties of the wind through kinematics analysis. Methods: We exploited VLT/VIMOS, VLT/SINFONI, and Subaru/IRCS adaptive optics (AO) data to study the kinematics properties on the scale of the host galaxy of XID5395; this galaxy is a luminous, X-ray obscured starburst/quasar (SB-QSO) merging system at z ~ 1.5, detected in the XMM-COSMOS field, associated with an extreme [O II] emitter (with equivalent width, EW, ~200 Å). For the first time, we mapped the kinematics of the [O III] and Hα line complexes and linked them with the [O II] emission at high resolution. The high spatial resolution achieved allowed us to resolve all the components of the SB-QSO system. Results: Our analysis, with a resolution of few kpc, reveals complexities and asymmetries in and around the nucleus of XID5395. The velocity field measured via non-parametric analysis reveals different kinematic components with maximum blueshifted and redshifted velocities up to ≳ 1300 km s-1 that are not spatially coincident with the nuclear core. These extreme values of the observed velocities and spatial location can be explained by the presence of fast moving material. We also spectroscopically confirm the presence of a merging system at the same redshift as the AGN host. Conclusions: We propose that EW as large as >150 Å in X-ray selected AGN may be an efficient criterion to isolate objects associated with the short, transition phase of "feedback" in the AGN-galaxy co-evolutionary path. This co-evolutionary path subsequently evolves into an unobscured QSO, as suggested from the different observational evidence (e.g. merger, compact radio emission, and outflow) we accumulated for XID5395.

  18. Time-resolved dosimetric verification of respiratory-gated radiotherapy exposures using a high-resolution 2D ionisation chamber array.

    PubMed

    King, R B; Agnew, C E; O'Connell, B F; Prise, K M; Hounsell, A R; McGarry, C K

    2016-08-01

    The aim of this work was to track and verify the delivery of respiratory-gated irradiations, performed with three versions of TrueBeam linac, using a novel phantom arrangement that combined the OCTAVIUS(®) SRS 1000 array with a moving platform. The platform was programmed to generate sinusoidal motion of the array. This motion was tracked using the real-time position management (RPM) system and four amplitude gating options were employed to interrupt MV beam delivery when the platform was not located within set limits. Time-resolved spatial information extracted from analysis of x-ray fluences measured by the array was compared to the programmed motion of the platform and to the trace recorded by the RPM system during the delivery of the x-ray field. Temporal data recorded by the phantom and the RPM system were validated against trajectory log files, recorded by the linac during the irradiation, as well as oscilloscope waveforms recorded from the linac target signal. Gamma analysis was employed to compare time-integrated 2D x-ray dose fluences with theoretical fluences derived from the probability density function for each of the gating settings applied, where gamma criteria of 2%/2 mm, 1%/1 mm and 0.5%/0.5 mm were used to evaluate the limitations of the RPM system. Excellent agreement was observed in the analysis of spatial information extracted from the SRS 1000 array measurements. Comparisons of the average platform position with the expected position indicated absolute deviations of  <0.5 mm for all four gating settings. Differences were observed when comparing time-resolved beam-on data stored in the RPM files and trajectory logs to the true target signal waveforms. Trajectory log files underestimated the cycle time between consecutive beam-on windows by 10.0  ±  0.8 ms. All measured fluences achieved 100% pass-rates using gamma criteria of 2%/2 mm and 50% of the fluences achieved pass-rates  >90% when criteria of 0.5%/0.5 mm were used. Results using this novel phantom arrangement indicate that the RPM system is capable of accurately gating x-ray exposure during the delivery of a fixed-field treatment beam. PMID:27384459

  19. Search for metastable heavy charged particles with large ionisation energy loss in pp collisions at $${\\sqrt{s} = 8}$$ s = 8 TeV using the ATLAS experiment

    DOE PAGESBeta

    Aad, G.

    2015-09-03

    Many extensions of the Standard Model predict the existence of charged heavy long-lived particles, such as R-hadrons or charginos. These particles, if produced at the Large Hadron Collider, should be moving non-relativistically and are therefore identifiable through the measurement of an anomalously large specific energy loss in the ATLAS pixel detector. Measuring heavy long-lived particles through their track parameters in the vicinity of the interaction vertex provides sensitivity to metastable particles with lifetimes from 0.6 ns to 30 ns. A search for such particles with the ATLAS detector at the Large Hadron Collider is presented, based on a data samplemore » corresponding to an integrated luminosity of \\(18.4\\) fb\\(^{-1}\\) of pp collisions at \\(\\sqrt{s} = 8\\) TeV. No significant deviation from the Standard Model background expectation is observed, and lifetime-dependent upper limits on R-hadrons and chargino production are set. Gluino R-hadrons with 10 ns lifetime and masses up to 1185 GeV are excluded at 95 \\(\\%\\) confidence level, and so are charginos with 15 ns lifetime and masses up to 482 GeV.« less

  20. Simultaneous determination of amiloride and hydrochlorothiazide in human plasma by liquid chromatography/tandem mass spectrometry with positive/negative ion-switching electrospray ionisation.

    PubMed

    Song, Min; Hang, Taijun; Zhao, Hua; Wang, Li; Ge, Ping; Ma, Pengcheng

    2007-01-01

    A new method for simultaneous determination of amiloride and hydrochlorothiazide by liquid chromatography/electrospray tandem mass spectrometry (LC/MS/MS) operated in positive and negative ionization switching mode was developed and validated. Protein precipitation with acetonitrile was selected for sample preparation. The analytes were separated on a Phenomenex Curosil-PFP (250x4.6 mm, 5 microm) column by a gradient elution with a mobile phase consisting of 0.15% formic acid solution containing 0.23% ammonium acetate and methanol pumped at a flow rate of 1.0 mL.min(-1). Rizatriptan was used as the internal standard (IS) for quantification. The determination was carried out on a Waters Quattro-micro triple-quadrupole mass spectrometer operated in multiple reaction monitoring (MRM) mode using the following transitions monitored simultaneously: positive m/z 230-->171 for amiloride, m/z 270-->158 for rizatriptan, and negative m/z 296-->205 for hydrochlorothiazide. The lower limits of quantification (LLOQs) were 0.1 and 1.0 ng.mL(-1) for amiloride and hydrochlorothiazide, respectively, which were lower than other published methods by using ultraviolet (UV), fluorimetric or mass spectrometric detection. The intra- and inter-day precision and accuracy were studied at three different concentration levels and were always better than 15% (n=5). This simple and robust LC/MS/MS method was successfully applied to the pharmacokinetic study of compound amiloride and hydrochlorothiazide tablets in healthy male Chinese volunteers. PMID:17902196

  1. OT2_alopezse_3: Mapping the cosmic ray ionisation rate across the Northern end of the Orion A iant molecular cloud

    NASA Astrophysics Data System (ADS)

    López-Sepulcre, A.

    2011-09-01

    Cosmic rays (CR) are ubiquitous in the Galaxy and have the important role of ionizing the dens gas of the ISM. New Herschel observations have shown the huge diagnostic power of the OH+ fundamental transition to measure the CR ionization rate in diffuse clouds. Based on previous "serendipity" observations toward OMC2-FIR4 within the KP CHESS, we discovered a tenuous foreground cloud absorbing the fundamental OH+ line. Similarly, Gupta et al. (2010) found an OH+ absorption component at a similar velocity towards Orion KL and estimated a large CR ionization rate more than 10 times larger than the average value observed in diffuse clouds . We propose here to roughly map the CR ionization rate in the direction of the OMC2 and OMC3 complex to understand its extent, nature, and, finally, the source of ionization.

  2. High resolution multiple electron impact ionisation of He, Ne, Ar, Kr and Xe atoms close to threshold: Appearance energies and Wannier exponents

    NASA Astrophysics Data System (ADS)

    Gstir, B.; Denifl, S.; Hanel, G.; Rümmele, M.; Fiegele, T.; Stano, M.; Feketeova, L.; Matejcik, S.; Becker, K.; Scheier, P.; Märk, T. D.

    2003-05-01

    We have determined appearance energies AE(X n+ /X) for the formation of multiply charged He, Ne, Ar, Kr and Xe ions up to charge state n=2 (He), n=4 (Ne), n=6 (Ar), n=6 (Kr) and n=8 (Xe) using a recently commissioned high-resolution electron impact ionization mass spectrometer. The data analysis is based on the Marquart-Levenberg algorithm, involving an iterative, non-linear least-squares fitting of the threshold data assuming a 2-function or a 3-function fit based on a Wannier-type power law. This allows us to extract the relevant AEs and corresponding Wannier exponents.

  3. Characterisation of serum transthyretin by electrospray ionisation-ion mobility mass spectrometry: Application to familial amyloidotic polyneuropathy type I (FAP-I).

    PubMed

    Pont, Laura; Benavente, Fernando; Vilaseca, Marta; Giménez, Estela; Sanz-Nebot, Victoria

    2015-11-01

    Transthyretin (TTR) is a homotetrameric protein which is known to misfold and aggregate causing different types of amyloidosis, such as familial amyloidotic polyneuropathy type I (FAP-I). FAP-I is associated with a specific TTR mutant variant (TTR (Met30)) that can be easily detected analysing the monomeric forms of the mutant protein. Meanwhile, the mechanism of protein aggregation onset, which could be triggered by structural changes on the native tetrameric protein complex, remains uncertain. We developed and described herein a new sample pretreatment based on immunoprecipitation (IP) to purify TTR from serum under non-denaturing conditions. Later, a nano-electrospray ionization-ion mobility mass spectrometry (nano-ESI-IM-MS or IM-MS) method was optimised to analyse the protein complexes in serum samples from healthy controls and FAP-I patients. IM-MS allowed separation and characterisation of tetrameric, trimeric and dimeric TTR gas ions due to their differential drift time, which is related to ion size and charge. The tetramer-to-dimer abundance ratio was differential between healthy controls and FAP-I patients (asymptomatic, symptomatic and an iatrogenic patient originally without the mutation who received a liver transplant from an FAP-I patient), and was also indicative of the effectiveness of liver transplantation as a treatment for FAP-I. PMID:26452950

  4. Non ionising radiation as a non chemical strategy in regenerative medicine: Ca(2+)-ICR "In Vitro" effect on neuronal differentiation and tumorigenicity modulation in NT2 cells.

    PubMed

    Ledda, Mario; Megiorni, Francesca; Pozzi, Deleana; Giuliani, Livio; D'Emilia, Enrico; Piccirillo, Sara; Mattei, Cristiana; Grimaldi, Settimio; Lisi, Antonella

    2013-01-01

    In regenerative medicine finding a new method for cell differentiation without pharmacological treatment or gene modification and minimal cell manipulation is a challenging goal. In this work we reported a neuronal induced differentiation and consequent reduction of tumorigenicity in NT2 human pluripotent embryonal carcinoma cells exposed to an extremely low frequency electromagnetic field (ELF-EMF), matching the cyclotron frequency corresponding to the charge/mass ratio of calcium ion (Ca(2+)-ICR). These cells, capable of differentiating into post-mitotic neurons following treatment with Retinoic Acid (RA), were placed in a solenoid and exposed for 5 weeks to Ca(2+)-ICR. The solenoid was installed in a μ-metal shielded room to avoid the effect of the geomagnetic field and obtained totally controlled and reproducible conditions. Contrast microscopy analysis reveled, in the NT2 exposed cells, an important change in shape and morphology with the outgrowth of neuritic-like structures together with a lower proliferation rate and metabolic activity alike those found in the RA treated cells. A significant up-regulation of early and late neuronal differentiation markers and a significant down-regulation of the transforming growth factor-α (TGF-α) and the fibroblast growth factor-4 (FGF-4) were also observed in the exposed cells. The decreased protein expression of the transforming gene Cripto-1 and the reduced capability of the exposed NT2 cells to form colonies in soft agar supported these last results. In conclusion, our findings demonstrate that the Ca(2+)-ICR frequency is able to induce differentiation and reduction of tumorigenicity in NT2 exposed cells suggesting a new potential therapeutic use in regenerative medicine. PMID:23585910

  5. Epidemiological studies of Fukushima residents exposed to ionising radiation from the Fukushima Daiichi Nuclear Power Plant prefecture--a preliminary review of current plans.

    PubMed

    Akiba, Suminori

    2012-03-01

    It is now more than six months since the beginning of the accident on 11 March 2011 at the Fukushima Daiichi Nuclear Power Plant in Japan. The Japanese government and local health authorities have started to collect the information necessary to estimate radiation doses received by those living in the area around the plant, drafted plans for the health care of residents, and started to implement some of them. This paper reviews and discusses the studies necessary for risk evaluation of cancer and non-cancer diseases, including those already planned, mainly from the view point of evaluating health risk using epidemiological approaches. In the long run, it is important to establish a cohort with a control group. Even if the cumulative doses are estimated to be so low that it is difficult to evaluate the risk of cancer and non-cancer diseases, it is necessary to conduct such a study to reassure residents. The health care programme of the Fukushima Prefecture government, including health check-ups of residents, will help to assess indirect effects of radiation exposure, including psychological problems. The success of any studies of radiation epidemiology depends on the collection of accurate information on radiation doses received by the study subjects. However, some of the dosimetry surveys were not conducted in a timely manner. (It should be recognised, though, that such a problem might have been inevitable, considering the chaotic condition after the nuclear accident.) Accurate estimation of the radiation dose received by each resident is not only important for scientific risk evaluation but also to inform each resident about his or her potential risk. Otherwise, residents will bear an undue psychological burden from uncertainties regarding their radiation exposure and its health consequences. One of other important tasks in Fukushima is the improvement of the quality of the regional cancer registry in this prefecture. It is also important to start thyroid cancer screening in a year or two since the expected minimum latent period among those exposed in early childhood is about 4 years. Recently, local health authorities decided to start a thyroid screening programme for those aged 18 years or younger. Any scientific efforts in Fukushima, which need to gain the trust of study subjects about the objectivity of research, may suffer from the fact that residents in Fukushima Prefecture have begun to suspect that the Japanese government and local authorities are keeping important information from them. It seems necessary to make more effort to reflect the opinions of residents when planning health care programmes and to gain the understanding of the public for the programme. In summary, there are many problems that make the evaluation of cancer and non-cancer disease risk in Fukushima difficult. The help of international colleagues will be invaluable for overcoming those problems. In this paper, these efforts are briefly summarised and some comments are made. PMID:22327057

  6. Radiations cosmiques : danger dans l'Espace

    NASA Astrophysics Data System (ADS)

    Bonnet-Bidaud, J. M.; Dzitko, H.

    2000-06-01

    Au sol, l'atmosphere nous protege plus ou moins bien. Mais dans l'espace ou a bord des avions de ligne, l'homme est directement expose aux rayonnements cosmiques qui peuvent etre mortels. Un veritable frein a la presence humaine prolongee dans l'espace. Une menace que les agences spatiales prennent tres au serieux.

  7. Women's Support, Women's Work: Child Care in an Era of Deficit Reduction, Devolution, Downsizing and Deregulation = Le soutien aux femmes, le travail des femmes et la garde d'enfants a l'ere de la reduction du deficit, du transfert des responsabilites, de la reduction de la taille de l'Etat et de la dereglementation.

    ERIC Educational Resources Information Center

    Doherty, Gillian; Friendly, Martha; Oloman, Mab

    Among the multiplicity of objectives that high quality child care can meet is the pivotal goal of promoting equality for women. Child care has consequences for women both as mothers and as providers of care for other people's children. Thus, women have a powerful stake in child care policy. Canada has no national child care policy, and its child…

  8. Préface

    NASA Astrophysics Data System (ADS)

    Ouerdane, Youcef; Laporte, Pierre

    2005-06-01

    'objet de très belles études, d'une part par génération dans les gaz et l'obtention bien maîtrisée et caractérisée de rayonnement attoseconde utilisé maintenant pour des mesures effectives de processus électroniques au sein des atomes, et d'autre part par focalisation sur cible solide. Ces derniers travaux (CEA et LOA), par mise en oeuvre du concept de “miroir plasma” qui combat l'ASE, ont permis de monter que la génération d'harmoniques cohérents sur solide était effective. - Dans le domaine des sources UV deux exposés ont présenté l'état de l'art des sources diodes ellesmêmes (LED et Lasers), ainsi que le développement des sources laser ps haute cadence (multikHz/MHz) avec génération d'harmoniques, de puissance moyenne élevée adaptée à de nombreux secteurs applicatifs (traitement des matériaux, biologie, microscopie...). L'aspect “sources”, au sens large était, on le voit, particulièrement représenté avec de belles perspectives pour les années qui viennent. Au delà de ces développements, les sources X ont été utilisées pour des réalisations instrumentales intéressantes dans le domaine de la microscopie X, de la microscopie interférentielle, et de la reconstruction 3D. De tels travaux sont susceptibles de rapides transferts en direction du secteur bio/santé. On notera également l'avancée que représente la réalisation d'un spectromètre à transformée de Fourier pour VUV/XUV (LCFIO/LPPM/SOLEIL). Le domaine du diagnostic, de la mesure, et de la modélisation dans les plasmas est, lui aussi, très actif avec des outils expérimentaux et théoriques très conséquents : modélisation des propriétés spectrales des ions multichargés (CEA-DAM) ; coefficients d'absorption de plasmas lasers (CEA-DSM, LULI, CEA-DAM) ; spectres d'absorption X dans les plasmas femtosecondes incluant des expériences type “pompe-sonde” résolues spatialement et spectralement (LULI, CEA-DAM, CELIA) ; interaction laseratome/molécule en r

  9. Matrix-assisted laser desorption/ionisation (MALDI) TOF analysis identifies serum angiotensin II concentrations as a strong predictor of all-cause and breast cancer (BCa)-specific mortality following breast surgery.

    PubMed

    Boccardo, Francesco; Rubagotti, Alessandra; Nuzzo, Pier Vitale; Argellati, Francesca; Savarino, Grazia; Romano, Paolo; Damonte, Gianluca; Rocco, Mattia; Profumo, Aldo

    2015-11-15

    MALDI-TOF MS was used to recognise serum peptidome profiles predictive of mortality in women affected by early BCa. Mortality was analysed based on signal profiling, and appropriate statistics were used. The results indicate that four signals were increased in deceased patients compared with living patients. Three of the four signals were individually associated with all-cause mortality, but only one having mass/charge ratio (m/z) 1,046.49 was associated with BCa-specific mortality and was the only peak to maintain an independent prognostic role after multivariate analysis. Two groups exhibiting different mortality probabilities were identified after clustering patients based on the expression of the four peptides, but m/z 1,046.49 was exclusively expressed in the cluster exhibiting the worst mortality outcome, thus confirming the crucial value of this peptide. The specific role of this peak was confirmed by competing risk analysis. MS findings were validated by ELISA analysis after demonstrating that m/z 1,046.49 structurally corresponded to Angiotensin II (ATII). In fact, mortality results obtained after arbitrarily dividing patients according to an ATII serum value of 255 pg/ml (which corresponds to the 66(th) percentile value) were approximately comparable to those previously demonstrated when the same patients were analysed according to the expression of signal m/z 1,046.49. Similarly, ATII levels were specifically correlated with BCa-related deaths after competing risk analysis. In conclusion, ATII levels were increased in women who exhibited worse mortality outcomes, reinforcing the evidence that this peptide potentially significantly affects the natural history of early BCa. Our findings also confirm that MALDI-TOF MS is an efficient screening tool to identify novel tumour markers and that MS findings can be rapidly validated through less complex techniques, such as ELISA. PMID:25994113

  10. A novel method for the analysis of the substitution pattern of O-methyl-[alpha]- and [beta]-1,4-glucans by means of electrospray ionisation-mass spectrometry/collision induced dissociation

    NASA Astrophysics Data System (ADS)

    Adden, Roland; Mischnick, Petra

    2005-03-01

    The substitution pattern of O-methyl amylose and O-methyl cellulose was analysed after per-O-methylation (Me-d3), and partial hydrolysis by subsequent ESI-MS/CID of the sodium (MS2) and the lithium adducts (MS3). Based on previous studies about the influence of regioselective O-methylation on the fragmentation pathways of malto- and cello-oligosaccharides, we could calculate the contribution of a certain methyl pattern to a distinct signal in the reproducible ESI-MS2 daughter spectrum. Signal intensities obtained from each O-methyl-O-methyl-d3 disaccharide were distributed on the corresponding methyl patterns and accumulated for all peaks of the mother mass spectrum. Data from ESI-MS2 were not sufficient for disaccharides bearing methyl and deuteromethyl groups in the combination 2 and 4, 3 and 3, or 4 and 2. Further independent information was obtained by ESI-MS3 of the lithium adducts. Monomer composition of methyl celluloses and methyl amyloses obtained by this novel approach were in very good agreement with reference data from GLC of the partially methylated glucitol acetates after complete hydrolysis, reduction and acetylation.

  11. A multi-residue method for the determination of pesticides in high water content matrices by gas chromatography-single quadrupole mass spectrometry with electron ionisation (EI-GC/MS).

    PubMed

    de Oliveira, Mauro Lúcio Gonçalves; Madureira, Fernando Diniz; Aurélio, Fabiano; Pontelo, Ana Paula; Silva, Gilsara; Oliveira, Reginaldo; Paes, Cláudia

    2012-01-01

    An EI-GC/MS method for the determination of pesticide residues in vegetable matrices with high water content was validated using papaya samples. The validation of a multi-residue pesticide method was in agreement with national and international regulations enabling the Ministry of the Agriculture, Livestock and Food Supply of Brazil to cover a large number of matrices and pesticide residues in its monitoring and control programmes. The extraction used 60 mL of ethyl acetate and 30 g of sample previously processed. After extraction, clean-up of all the extracts was carried out by percolation through GBC cartridges. The samples were then injected in an EI-GC/MS system. Calibration curves were prepared in quadruplet by fortifying blank extracts with a standard solution containing all the pesticides studied at 0.000, 0.005, 0.010, 0.020, 0.030, 0.050, 0.080 and 0.100 mg kg(-1). For the recovery study, blank samples were fortified at 0.010, 0.020, 0.030, 0.050 and 0.080 mg kg(-1) and then submitted to the extraction procedure. The complete procedure was repeated over four different days by two analysts. The regression parameters of calibration curves were calculated for each validation day. Linearity, selectivity, specificity, robustness, limits of detection and quantification were also assessed. The uncertainty was estimated for each analyte at each spike level studied. The method had recoveries between 91% and 105% and precision results ≤ 20%. Limits of quantification were below or equal to the maximum residue limits (MRLs) regulated by Brazilian legislation. The MRLs of the selected pesticides are not regulated by CODEX Alimentarius. The results are also in agreement with SANCO/10684/2009. PMID:22292605

  12. Non Ionising Radiation as a Non Chemical Strategy in Regenerative Medicine: Ca2+-ICR “In Vitro” Effect on Neuronal Differentiation and Tumorigenicity Modulation in NT2 Cells

    PubMed Central

    Ledda, Mario; Megiorni, Francesca; Pozzi, Deleana; Giuliani, Livio; D’Emilia, Enrico; Piccirillo, Sara; Mattei, Cristiana; Grimaldi, Settimio; Lisi, Antonella

    2013-01-01

    In regenerative medicine finding a new method for cell differentiation without pharmacological treatment or gene modification and minimal cell manipulation is a challenging goal. In this work we reported a neuronal induced differentiation and consequent reduction of tumorigenicity in NT2 human pluripotent embryonal carcinoma cells exposed to an extremely low frequency electromagnetic field (ELF-EMF), matching the cyclotron frequency corresponding to the charge/mass ratio of calcium ion (Ca2+-ICR). These cells, capable of differentiating into post-mitotic neurons following treatment with Retinoic Acid (RA), were placed in a solenoid and exposed for 5 weeks to Ca2+-ICR. The solenoid was installed in a μ-metal shielded room to avoid the effect of the geomagnetic field and obtained totally controlled and reproducible conditions. Contrast microscopy analysis reveled, in the NT2 exposed cells, an important change in shape and morphology with the outgrowth of neuritic-like structures together with a lower proliferation rate and metabolic activity alike those found in the RA treated cells. A significant up-regulation of early and late neuronal differentiation markers and a significant down-regulation of the transforming growth factor-α (TGF-α) and the fibroblast growth factor-4 (FGF-4) were also observed in the exposed cells. The decreased protein expression of the transforming gene Cripto-1 and the reduced capability of the exposed NT2 cells to form colonies in soft agar supported these last results. In conclusion, our findings demonstrate that the Ca2+-ICR frequency is able to induce differentiation and reduction of tumorigenicity in NT2 exposed cells suggesting a new potential therapeutic use in regenerative medicine. PMID:23585910

  13. Carbon nano structures: Production and characterization

    NASA Astrophysics Data System (ADS)

    Beig Agha, Rosa

    recherche sur l'hydrogene (IRH). Nos echantillons presentaient toujours une grande quantite de carbure de fer au detriment de la formation de nanostructures de carbone. Apres plusieurs mois de recherche nous avons constate que les metaux de base, soit le fer et le cobalt, etaient contamines. Neanmoins, ces recherches nous ont enseigne beaucoup et les resultats sont presentes aux Appendices I a III. Le carbone de depart est du charbon active commercial (CNS201) qui a ete prealablement chauffe a 1,000°C sous vide pendant 90 minutes pour se debarrasser de toute humidite et autres impuretes. En premiere etape, dans un creuset d'acier durci du CNS201 pretraite fut melange a une certaine quantite de Fe et de Co (99.9 % purs). Des proportions typiques sont 50 pd. %, 44 pd. %, et 6 pd. % pour le C, le Fe, et le Co respectivement. Pour les echantillons prepares avec le broyeur SPEX, trois a six billes en acier durci furent utilisees pour le broyage, de masse relative echantillon/poudre de 35 a 1. Pour les echantillons prepares avec le broyeur planetaire, trente-six billes en acier durci furent utilisees pour le broyage, de masse relative echantillon/poudre de 10 a 1. L'hydrogene fut alors introduit dans le creuset pour les deux types de broyeur a une pression de 1.4 MPa, et l'echantillon fut broye pendant 12 h pour le SPEX et 24 h pour le planetaire. Le broyeur SPEX a un rendement de transfert d'energie mecanique plus grand qu'un broyeur planetaire, mais il a le desavantage de contaminer davantage l'echantillon en Fe par attrition. Cependant, ceci peut etre neglige vu que le Fe etait un des catalyseurs metalliques ajoutes au creuset. En deuxieme etape, l'echantillon broye est transfere sous gaz inerte (argon) dans un tube en quartz, qui est alors chauffe a 700°C pendant 90 minutes. Des mesures de patrons de diffraction a rayons-X sur poudre furent faites pour caracteriser les changements structurels des CNS lors des etapes de synthese. Ces mesures furent prises avec un

  14. SIRIUS FEL project

    NASA Astrophysics Data System (ADS)

    Roche, Michel; Moret-Bailly, Jacques

    1991-07-01

    This article presents a 6 MV electrostatic accelerator-driven free electron laser project, with a wavelength range of 80 to 1000 μm. The study of this facility, called SIRIUS (source intense de rayonnement infra-rouge pour utilisations scientifiques), is based on the facility realized by Elias at the University of California, Santa Barbara. We plan to improve some important technological features.

  15. La prise en charge à long terme de l’asthme chez les enfants inuits et des Premières nations : un outil de transfert du savoir fondé sur les lignes directrices canadiennes pour l’asthme pédiatrique, conçu pour être utilisé par les professionnels de la santé de première ligne qui travaillent dans des communautés isolées

    PubMed Central

    Kovesi, Tom; Giles, Brenda Louise; Pasterkamp, Hans

    L’asthme est un grave problème de santé pour les enfants inuits et des Premières nations. Chez les enfants de moins d’un an, il faut distinguer l’asthme de la bronchiolite virale, anormalement fréquente chez les enfants autochtones du Canada. Chez les enfants de moins de six ans, le diagnostic dépend de la présence de symptômes classiques, de l’absence de caractéristiques atypiques et de la consignation de la réponse au traitement, notamment la réponse rapide et transitoire aux bronchodilatateurs. Chez les enfants plus âgés, il faut, dans la mesure du possible, déterminer la présence d’une obstruction réversible des voies aériennes par spirométrie afin de confirmer le diagnostic, ainsi qu’évaluer et corriger les déclencheurs environnementaux. L’utilisation régulière de corticoïdes en aérosol est la principale mesure à prendre pour maintenir un bon contrôle de l’asthme chez les enfants asthmatiques. Les clients et leur famille devraient recevoir une formation sur l’asthme. Il faut réévaluer régulièrement le contrôle aux visites de suivi dans des centres de santé et rajuster le traitement à la dose la plus basse possible pour le maintien de ce contrôle.

  16. The Use of Video in Knowledge Transfer of Teacher-Led Psychosocial Interventions: Feeling Competent to Adopt a Different Role in the Classroom (L'utilisation de la vidéo dans le transfert de connaissances dans les interventions psychosociales menées par les enseignants : sentir que l'on a la compétence d'adopter un rôle différent dans la salle de classe)

    ERIC Educational Resources Information Center

    Beauregard, Caroline; Rousseau, Cécile; Mustafa, Sally

    2015-01-01

    Because they propose a form of modeling, videos have been recognised to be useful to transfer knowledge about practices requiring teachers to adopt a different role. This paper describes the results of a satisfaction survey with 98 teachers, school administrators and professionals regarding their appreciation of training videos showing teacher-led…

  17. Electron scattering studies of DMS, DMDS and DMSO homologous series

    NASA Astrophysics Data System (ADS)

    Kaur, Jaspreet; Singh, Suvam; Antony, Bobby

    2015-12-01

    The present paper reports ionisation, elastic and total cross section for the first three members of dimethyl sulphide, dimethyl disulphide and dimethyl sulphoxide family of molecules. The multi-scattering centre spherical complex optical potential formalism is applied for integral elastic and inelastic cross section calculations. From the inelastic part, ionisation cross section is derived using complex scattering potential-ionisation contribution method. The total cross section is then obtained from the sum of elastic and inelastic contributions. A reasonably good agreement is obtained for elastic cross section, wherever comparison is available. The ionisation and total cross section calculation for the complete set of molecules has been performed for the first time.

  18. Photoionisation of ions with synchrotron radiation: from ions in space to atoms in cages

    NASA Astrophysics Data System (ADS)

    Schippers, Stefan; Kilcoyne, A. L. David; Phaneuf, Ronald A.; Müller, Alfred

    2016-04-01

    The photon-ion merged-beams technique for the photoionisation of mass/charge selected ionised atoms, molecules and clusters by x-rays from synchrotron radiation sources is introduced. Examples for photoionisation of atomic ions are discussed by going from outer shell ionisation of simple few electron systems to inner shell ionisation of complex many electron ions. Fundamental ionisation mechanisms are elucidated and the importance of the results for applications in astrophysics and plasma physics is pointed out. Finally, the unique capabilities of the photon-ion merged-beams technique for the study of photoabsorption by nanoparticles are demonstrated by the example of endohedral fullerene ions.

  19. Electron Impact Ionization Cross Sections in Rb and Cs.

    NASA Astrophysics Data System (ADS)

    Reddish, T. J.; Lukomski, M.; Sutton, S.; Kedzierski, W.; McConkey, J. W.; Bartschat, K.; Bartlett, P. L.; Stelbovics, A. T.; Bray, I.

    2006-05-01

    We present a new atom trapping technique for determining absolute, total ionisation cross sections (TICS) out of an excited atom. The novel feature of this method is in utilizing Doppler cooling of neutral atoms to determine ionisation cross sections. This fluorescence-monitoring experiment, which is a variant of the `trap loss' technique, has enabled us to obtain the experimental electron impact ionisation cross sections out of the Cs 6^2P3/2 excited state between 7 - 400 eV. New CCC, R-Matrix with Pseudo-States (RMPS), and Born approximation single ionisation cross sections (SICS) are also presented for both the ground and excited states of Cs and Rb, and compared with the available experimental data. The comparison of the results reveals the importance of the autoionisation and multiple ionisation contributions to the TICS. The autoionisation contribution appears to be substantial for ionisation out of the Cs 6^2P and Rb 5^2P excited states; ˜ 3-4 larger than the direct ionisation contribution predicted by CCC at ˜ 30-50 eV. This surprising result shows the importance of multi-electron processes in determining the ionisation cross sections of heavy alkali atoms.

  20. Facteurs de risque de mortalité chez les nouveaux-nés transférés au service de néonatologie de l'Hôpital Jason Sendwe de Lubumbashi, République Démocratique du Congo

    PubMed Central

    Katamea, Tina; Mukuku, Olivier; Kamona, Lewis; Mukelenge, Kethye; Mbula, Otikeke; Baledi, Lambert; Ntambwe, Emile; Mutombo, Augustin Mulangu; Wembonyama, Stanis Okitotsho; Luboya, Oscar Numbi

    2014-01-01

    Introduction La mortalité néonatale reste préoccupante dans notre milieu et plusieurs facteurs dont ceux liés à l'organisation du transfert de nouveau-nés au niveau des structures de prise en charge y contribuent. Les objectifs de notre étude sont de déterminer la fréquence du transfert néonatal extrahospitalier à l'unité de néonatologie et identifier les facteurs de risque de mortalité dans notre milieu. Méthodes Il s'agit d'une étude prospective et analytique menée sur une période de douze mois allant du 1er Janvier 2012 au 31 décembre 2012 ayant ciblé tous les nouveau-nés transférés des maternités extérieurs, traités et suivis dans le service de néonatologie de l'hôpital Sendwe. Les caractéristiques maternelles (âge, parité, état-civil, profession, niveau d’étude, antécédents médicaux et toxicologiques) et perpartales (âge gestationnel, état de la poche des eaux, voie d'accouchement) et néonataux (âge lors du transfert, sexe, poids de naissance, moyen de transfert, motif de transfert et évolution (guérison ou décès)) ont été étudiés. La saisie et l'analyse des données ont été faites sur le logiciel Epi Info 2011 (version 7.0.8.3) et le seuil de signification de 5%. Résultats La fréquence du transfert néonatal extrahospitalier est de 12,9%. La mortalité était significativement liée à la profession (vendeuse ou travailleuse) de la mère (OR = 7,43 (1,38-39,97)), au niveau d’étude élevé (OR = 4,22 (1,18-15,10)), à l’âge gestationnel <37 SA (OR=3,21 (1,46-7,06)), à l’accouchement par voie basse de manière dystocique (OR=6,50 (1,54-27,38)), au sexe masculin du nouveau-né (OR=2,43 (1,08-5,46)), au poids de naissance <1500 grammes (OR=15,3 (5,73-40,78)) et à la prématurité comme motif de transfert (OR=5,56 (1,47-20,98)). Conclusion Le bilan de la mortalité néonatale est lourd dans les pays en développement où les nouveau-nés continuent de mourir pour des causes souvent évitables. La r

  1. Caractérisation spectrale et temporelle de l'émission X issue de l'interaction laser-agrégats

    NASA Astrophysics Data System (ADS)

    Bonté, C.; Fourment, C.; Harmand, M.; Jouin, H.; Micheau, S.; Peyrusse, O.; Pons, B.; Santos, J. J.

    2006-12-01

    Les agrégats de gaz rares constituent un état de la matière intermédiaire entre les cibles solides massives et les atomes en phase gazeuse. Il a été démontré que les agrégats irradiés sont sources d'ions, d'électrons, de neutrons ainsi que de rayonnement allant du visible aux X durs. Cette source peut-être produite avec un taux de répétition élevé et a l'avantage de ne pas produire de débris, dommageables pour les optiques notamment, et de présenter une très forte conversion de l'énergie laser incidente. Nous nous intéressons au rayonnement X particulièrement, en le caractérisant en intensité, spectre et durée, comme préalable à toute application de cette source X et comme moyen privilégié d'étude de la physique des plasmas nanométriques chauds et denses. En collaboration avec l'INRS-Énergie (Varenne, Qc, Canada), nous avons mis en œuvre une caméra à balayage de fente dont la résolution temporelle est de 800 fs rms. En focalisant des impulsions laser courtes (30 fs 5 ps) et intenses (jusqu'à 1017 W/cm2) sur des agrégats d'argon dont le rayon varie de 15 à 30 nm, nous avons démontré que l'émission X dont l'énergie est supérieure à 2 keV est plus courte que 2 ps, limité par la résolution temporelle. En couplant la caméra à un cristal tronconique, dont la conception a été réalisée au LULI (Palaiseau, France), nous nous sommes intéressés au rayonnement de couche K dans la gamme 2,9 - 3,2 keV. Nous avons démontré que ce rayonnement a une durée inférieure à 3 ps (limite de la résolution temporelle), et que les raies étaient émises avec un écart relatif inférieur à 1 ps. Une simulation basée sur le modèle nano-plasma proposé par T. Ditmire et sur le code collisionnel-radiatif Transpec a été développée au CELIA. Les spectres X résolus en temps calculés reproduisent à la fois la brièveté d'émission du rayonnement X et les états de charge élevés observés.

  2. Reactions of the ionized enol tautomer of acetanilide: elimination of HNCO via a novel rearrangement.

    PubMed

    Heydorn, Lisa N; Carter, Lynn M; Bowen, Richard D; Terlouw, Johan K

    2003-01-01

    The reactions of ionised acetanilide, C(6)H(5)NH(=O)CH(3)(.+), and its enol, C(6)H(5)NH(OH)=CH(2)(.+), have been studied by a combination of tandem mass spectrometric and computational methods. These two isomeric radical cations have distinct chemistries at low internal energies. The keto tautomer eliminates exclusively CH(2)=C=O to give ionised aniline. In contrast, the enol tautomer loses H-N=C=O, via an unusual skeletal rearrangement, to form predominantly ionised methylene cyclohexadiene. Hydrogen atom loss also occurs from the enol tautomer, with the formation of protonated oxindole. The mechanisms for H-N=C=O and hydrogen atom loss both involve cyclisation; the former proceeds via a spiro transition state formed by attachment of the methylene group to the ipso position, whereas the latter entails the formation of a five-membered ring by attachment to the ortho position. The behaviour of labelled analogues reveals that these two processes have different site selectivities. Hydrogen atom loss involves a reverse critical energy and is subject to an isotope effect. Surprisingly, attempts to promote the enolisation of ionised acetanilide by proton-transport catalysis were unsuccessful. In a reversal of the usual situation for ionised carbonyl compounds, ionised acetanilide is actually more stable than its enol tautomer. The enol tautomer was resistant to proton-transport catalysed ketonisation to ionised acetanilide, possibly because the favoured geometry of the encounter complex with the base molecule is inappropriate for facilitating tautomerisation. PMID:12939486

  3. [Morphology determination of multi-needle bipolar corona discharge by OES].

    PubMed

    Chen, Hai-Feng; Su, Peng-Hao; Zhu, Yi-Min

    2009-01-01

    Using the method of OES (optical emission spectrum) for measuring N2 emission spectrum, the spacial distribution of energetic electrons in multi-needle bipolar corona discharge at atmospheric pressure was investigated. According to the distribution of N2 second positive band's intensity ISPB, the outline of ionisation region was drawn accurately. The relationship between ISPB and discharge current I was obtained through the sum of ISPB. There are two ionisation regions in the multi-needle bipolar corona discharge. One is near the HV electrode and the other is near the grounded electrode. The ionisation region exists around the needlepoint within 2-3 mm. The volume of ionisation region becomes big with the applied voltage U increasing. The ionisation region of negative corona is bigger than that of positive corona. Near the HV discharge electrode, the outline of electron avalanche is similar to the configuration of electric field lines in the ionisation region, so the electron avalanche along the axis direction of needle develops farther than that along the radial direction. The electric field in the migration area is weak, and the distribution of space charges is large along the radial direction. The sum of ISPB in each ionisation region is second order linear with I, but the quadratic coefficient is very small. So the sum of ISPB is nearly linear with I, the distribution of ISPB is corresponding to the density distribution of energetic electrons. So the charged particles forming the discharge current in ionisation region are electrons. No emission spectrum of N2 can be measured in migration area, so there is no energetic electron. The energetic electrons only exist in ionisation region and the charged particles in migration area are ions. PMID:19385198

  4. New ideas about the solubility of drugs.

    PubMed

    Box, Karl; Comer, John E; Gravestock, Tom; Stuart, Martin

    2009-11-01

    Methods are described for detecting precipitation of ionisable drugs under conditions of changing pH, estimating kinetic solubility from the onset of precipitation, and measuring solubility by chasing equilibrium. Definitions are presented for kinetic, equilibrium, and intrinsic solubility of ionisable drugs, supersaturation and subsaturation, and for chasers and non-chasers, which are two classes of ionisable drug with significantly different solubility properties. The use of Bjerrum Curves and Neutral-Species Concentration Profiles to depict solubility properties are described and illustrated with case studies showing super-dissolving behaviour, conversion between crystalline forms and enhancement of solubility through supersaturation, and the use of additives and simulated gastrointestinal fluids. PMID:19937815

  5. Interstellar CH, CH+ and abundance of atomic species

    NASA Astrophysics Data System (ADS)

    Gnacinski, P.; Krogulec, M.; Krelowski, J.

    2007-12-01

    The CH molecule is the only one molecule from the visual spectral range observed in two ionisation stages. The production of CH+ is commonly assigned to shock fronts, since the reaction C+ + H2 -> CH+ + H is endothermic. Moreover a velocity difference between the CH and CH+ spectral lines is often observed. We compare the CH/CH+ column densities with that of neutral and ionised atoms. The CH column density correlates better with neutral atoms, while column density of CH+ correlates better with ionised ones.

  6. Conduction of Electricity through Gases

    NASA Astrophysics Data System (ADS)

    Thomson, J. J.; Thomson, G. P.

    2013-06-01

    1. Electrical conductivity of gases in a normal state; 2. Properties of a gas when in a conducting state; 3. Mobility of ions; 4. Mathematical theory of the conduction of electricity through a gas containing ions; 5. Effect produced by a magnetic field on the motion of the ions; 6. Determination of the ratio of the charge to the mass of an ion; 7. Determination of the charge carried by the negative ion; 8. On some physical properties of gaseous ions; 9. Ionisation by incandescent solids; 10. Ionisation in gases from flames; 11. Ionisation by light. Photo-electric effects; Name index; Subject index.

  7. A model for the nonlocal transport and the associated distribution function deformation in magnetized laser-plasmas

    NASA Astrophysics Data System (ADS)

    Nicolaï, Ph.; Feugeas, J.-L.; Schurtz, G.

    2006-06-01

    We present a model of nonlocal transport for multidimensional radiation magneto hydrodynamic codes. In laser produced plasmas, it is now believed that the heat transfert can be strongly modified by the nonlocal nature of the electron conduction. Nevertheless other mechanisms as self generated magnetic fields may affect heat transport too. The model described in this work aims at extending the formula of G. Schurtz, Ph. Nicolaï and M. Busquet [1] to magnetized plasmas. A system of nonlocal equations is derived from kinetic equations with self-consistent electric and magnetic fields. These equations are analyzed and applied to a physical problem in order to demonstrate the main features of the model.

  8. The Rita Network.: how the High Energy Tools can BE Used in Order to Transmit Clinical Hadrontherapic Data

    NASA Astrophysics Data System (ADS)

    Ferraris, M.; Risso, P.; Squarcia, S.

    We present the realization done for the organization, selection, transmission of Radiotherapy's data and images. The choice of a standard healthcare records, based on the stereotactic and/or conformational radiotherapy, the implementation of the healthcare file into a distributed data-base using the World Wide Web platform for data presentation and transmission and the availability in the network is presented. The solution chosen is a good example of technology transfert from High Energy physics and Medicine and opens new interesting ways in this field.

  9. Resonant Ionization Laser Ion Source Project at TRIUMF

    NASA Astrophysics Data System (ADS)

    Lassen, J.; Bricault, P.; Dombsky, M.; Lavoie, J. P.; Geppert, Ch.; Wendt, K.

    2005-04-01

    Resonant laser excitation and ionisation is one of the most successful tools for the selective production of radioactive ion beams (RIB) at on-line mass separator facilities. TRIUMF plans to augment the current ion sources with a resonant ionisation laser ion source (RILIS), to use the high production yields from the target, as shown by the delivery of 3*104/s 11Li ions from a standard target ion source with surface ionisation. The development and installation of TRIUMF's RILIS (TRILIS) is necessary to provide beams of short lived isotopes that conventional ion sources could not produce in sufficient intensity and purity for nuclear-, and nuclear astrophysics- experiments. A laser system consisting of three tunable titanium sapphire (TiSa) lasers with frequency doubling and tripling was employed to demonstrate first off-line resonance ionisation of Ga, and is being installed for first on-line test and a run on 62Ga in December 2004.

  10. NICIL: A Stand Alone Library to Self-Consistently Calculate Non-Ideal Magnetohydrodynamic Coefficients in Molecular Cloud Cores

    NASA Astrophysics Data System (ADS)

    Wurster, James

    2016-09-01

    In this paper, we introduce Nicil: Non-Ideal magnetohydrodynamics Coefficients and Ionisation Library. Nicil is a stand-alone Fortran90 module that calculates the ionisation values and the coefficients of the non-ideal magnetohydrodynamics terms of Ohmic resistivity, the Hall effect, and ambipolar diffusion. The module is fully parameterised such that the user can decide which processes to include and decide upon the values of the free parameters, making this a versatile and customisable code. The module includes both cosmic ray and thermal ionisation; the former includes two ion species and three species of dust grains (positively charged, negatively charged, and neutral), and the latter includes five elements which can be doubly ionised. We demonstrate tests of the module, and then describe how to implement it into an existing numerical code.

  11. Nanodosimetry, from radiation physics to radiation biology.

    PubMed

    Grosswendt, B

    2005-01-01

    In view of the fact that early damage to genes and cells by ionising radiation starts with the early damage to segments of the DNA, it is a great challenge to radiation research to describe the general behaviour of ionising radiation in nanometric target volumes (nanodosimetry). After summarising basic aspects of nanodosimetry, an overview is given about its present state. As far as experimental procedures are concerned, main emphasis is laid on single-ion counting and single-electron counting methods, which use millimetric target volumes filled with a low-pressure gas to simulate nanometric target volumes at unit density. Afterwards, physical principles are discussed, which can be used to convert experimental ionisation cluster-size distributions into those caused by ionising radiation in liquid water. In the final section, possibilities are analysed of how to relate parameters derived from the probability of cluster-size formation in liquid water to parameters derived from radiobiological experiments. PMID:16381675

  12. Model of optical nonlinearity of air in the mid-IR wavelength range

    SciTech Connect

    Geints, Yu E; Zemlyanov, A A

    2014-09-30

    A model of optical nonlinearity of air (atmospheric nitrogen and oxygen) is developed. This model can be used to calculate numerically the propagation of radiation with a wavelength close to 10 μm. It takes into account the electronic Kerr effect, higher order nonlinearities, ionisation of a gas medium by electron impact, and pulse group-velocity dispersion. The applicability limits of the Drude approximation for calculating the impact-ionisation rate are also considered. (nonlinear optical phenomena)

  13. Nanodosimetry, the metrological tool for connecting radiation physics with radiation biology.

    PubMed

    Grosswendt, B

    2006-01-01

    It is generally accepted that the early damage to genes or cells by ionising radiation starts with the early damage to segments of the DNA, at least, to the greater part. This damage is the result of the spatial distribution of inelastic interactions of single ionising particles within the DNA or in its neighbourhood and is, in consequence, determined by the stochastics of particle interactions in volumes a few nanometre in size. Due to the latter fact radiation damage strongly depends on radiation quality and cannot be described satisfactorily in detail by macroscopic quantities like absorbed dose or linear energy transfer (LET). It can, however, be described approximately by the probability distribution of ionisation cluster-size formation in nanometric target volumes of liquid water (nanodosimetry). One aim of nanodosimetry is, therefore, to measure the radiation induced frequency distribution of ionisation cluster-size formation in liquid water, as a substitute for sub-cellular material, in volumes which are comparable in size with those of the most probable radio-sensitive volumes of biological systems. After a short description of the main aspects of cluster-size formation by ionising particles, an overview is given about the measuring principles applied in present-day nanodosimetric measurements. Afterwards, physical principles are discussed which can be used to convert ionisation cluster-size distributions measured in gases into those caused by ionising radiation in liquid water. In a final section, the probability distribution of ionisation cluster-size formation in liquid water is discussed from the point of view of damage formation to segments of the DNA. PMID:17169948

  14. The feasibility of RIMS for the analysis of potentially toxic element accumulation in neural tissue

    SciTech Connect

    Jones, O. Rhodri; Abraham, Christopher J.; Telle, Helmut H.; Oakley, Arthur E.

    1997-01-15

    A feasibility study was conducted into the possibility of using resonance ionisation mass spectrometry for the detection of focal accumulation of neuro-toxic elements in neural tissue. Experiments were performed using a ToFMS system in conjunction with an Ar{sup +} source for target sputtering and a pulsed tuneable dye laser system for resonance ionisation. Detection limits of {approx}3 ppm for Al in brain tissue homogenates were achieved, with a spatial resolution of less than 100 {mu}m.

  15. Evaluating drug delivery with salt formation: Drug disproportionation studied in situ by ATR-FTIR imaging and Raman mapping.

    PubMed

    Ewing, Andrew V; Wray, Patrick S; Clarke, Graham S; Kazarian, Sergei G

    2015-01-01

    Two different vibrational spectroscopic approaches, ATR-FTIR spectroscopic imaging and Raman mapping, were used to investigate the components within a tablet containing an ionised drug during dissolution experiments. Delivering certain drugs in their salt form is a method that can be used to improve the bioavailability and dissolution of the poorly aqueous soluble materials. However, these ionised species have a propensity to covert back to their thermodynamically favourable free acid or base forms. Dissolution experiments of the ionised drug in different aqueous media resulted in conversion to the more poorly soluble free acid form, which is detrimental for controlled drug release. This study investigates the chemical changes occurring to formulations containing a development ionised drug (37% by weight), in different aqueous pH environments. Firstly, dissolution in a neutral medium was studied, showing that there was clear release of ionised monosodium form of the drug from the tablet as it swelled in the aqueous medium. There was no presence of any drug in the monohydrate free acid form detected in these experiments. Dissolution in an acidic (0.1M HCl) solution showed disproportionation forming the free acid form. Disproportionation occurred rapidly upon contact with the acidic solution, initially resulting in a shell of the monohydrate free acid form around the tablet edges. This slowed ingress of the solution into the tablet before full conversion of the ionised form to the free acid form was characterised in the spectroscopic data. PMID:25910459

  16. Resonance-enhanced two-photon ionization of helium using an Ar{sup +} mode-locked laser synchronized with VUV synchrotron radiation pulses

    SciTech Connect

    Lacoursiere, Jean; Meyer, Michael; Nahon, Laurent; Morin, Paul; Larzilliere, Michel

    1995-04-01

    We report a new experimental set-up consisting in the synchronization of 74.9094 MHz pulses from a mode-locked Ar{sup +} laser with 8.32 MHz pulses of vacuum ultraviolet (VUV) synchrotron radiation from the Super-ACO storage ring of the Laboratorie pour l'Utilisation du Rayonnement Electromagnetique (LURE). The capabilities of the set-up are demonstrated in a time-resolved pump-probe (VUV+visible) experiment in which free helium atoms are resonantly ionized via the short-lived 1s3p ({sup 1}P) state. This experiment allowed us to show the relevance of this technique for the investigation of nanosecond dynamics on gas phase species.

  17. Études par diffraction de fibres de l'ADN double brin

    NASA Astrophysics Data System (ADS)

    Forsyth, V. T.; Parrot, I. M.

    2005-11-01

    L'état fibreux est un état naturel pour les molécules de polymère qui ont tendance à adopter des conformations hélicoïdales régulières plutôt que des structures globulaires caractéristiques à de nombreuses protéines. La diffraction de fibres a donc une application étendue pour l'étude d'une grande variété de polymères biologiques et synthétiques. Ce papier a pour objectif d'illustrer l'étendue générale de la méthode et, en particulier, de démontrer l'impact des sources modernes de rayonnement synchrotron et de faisceaux neutroniques.

  18. Resonance-enhanced two-photon ionization of helium using an Ar+ mode-locked laser synchronized with VUV synchrotron radiation pulses

    NASA Astrophysics Data System (ADS)

    Lacoursière, Jean; Meyer, Michael; Nahon, Laurent; Morin, Paul; Larzillière, Michel

    1995-04-01

    We report a new experimental set-up consisting in the synchronization of 74.9094 MHz pulses from a mode-locked Ar+ laser with 8.32 MHz pulses of vacuum ultraviolet (VUV) synchrotron radiation from the Super-ACO storage ring of the Laboratorie pour l'Utilisation du Rayonnement Electromagnetique (LURE). The capabilities of the set-up are demonstrated in a time-resolved pump-probe (VUV+visible) experiment in which free helium atoms are resonantly ionized via the short-lived 1s3p (1P) state. This experiment allowed us to show the relevance of this technique for the investigation of nanosecond dynamics on gas phase species.

  19. Spontaneous emission of the Super-ACO fel optical klystron domino

    NASA Astrophysics Data System (ADS)

    Couprie, M. E.; Bazin, C.; Billardon, M.; Velghe, M.

    1989-12-01

    New free electron laser experiments are planned on the Orsay storage ring Super-ACO, which has been commisioned in 1987 at LURE (Laboratoire d'Utilisation du Rayonnement Electromagnétique). For this purpose, a new insertion device, DOMINO, was set up on Super-ACO in January 1988; it consists of a permanent magnet optical klystron composed of two undulators separated by a dispersive section; the magnetic gaps can be changed independently. Here, the parameters of the optical klystron are specified, and the main steps of the optimization are described. Then, the effect of the insertion device on the stored beam is discussed. The spontaneous emission of the optical klystron has been observed and analysed. Consequently, with the ring parameters measurements, the free electron laser gain versus the current can be evaluated.

  20. Time-resolved pump-probe photoelectron spectroscopy of helium using a mode-locked laser synchronized with synchrotron radiation pulses

    NASA Astrophysics Data System (ADS)

    Lacoursière, Jean; Meyer, Michael; Nahon, Laurent; Morin, Paul; Larzillière, Michel

    1994-12-01

    We report a new experimental setup consisting in the synchronization of 74.9094 MHz pulses from a mode-locked Ar + laser with 8.32 MHz pulses of vacuum ultraviolet (VUV) synchrotron radiation from the Super-ACO storage ring of the Laboratoire pour l'Utilisation du Rayonnement Electromagnétique (LURE). The capabilities of the setup are demonstrated in a time-resolved pump-probe (VUV + visible) experiment in which free helium atoms are resonantly ionized via the short-lived 1s3p ( 1P) state. This experiment allowed us to obtain the value of 1.12 ns for the temporal resolution (FWHM) of the experimental setup and to show the relevance of this technique for the investigation of nanosecond dynamics on gas phase species.

  1. André Saint-Marc 1944-1988

    NASA Astrophysics Data System (ADS)

    Reme, H.; Anderson, K. A.

    Andr Śaint-Marc, professor at the Institute of Technology of the Universite Paul Sabatier (IUT), in Toulouse, France, died suddenly and unexpectedly February 17, 1988, a few months before his 44th birthday.Saint-Marc carried out a research career in cosmic rays and space plasma physics beginning in 1969 at the Centre d'Etude Spatiale des Rayonnements (CESR), a laboratory of the Centre National de la Recherche Scientifique (CNRS) and the Université Paul Sabatier. He was born in Condegaygues, France (Lotet-Garonne). His four university degrees were awarded by the Universite Paul Sabatier. His Thèse de Docteur de Specialité was earned in 1973 for work on propagation of auroral X rays in Earth's atmosphere. The highest degree, the Doctorat d'Etat, came in 1979 for his studies of beam-plasma interactions in the ionosphere.

  2. Mars Science Laboratory Using Laser Instrument, Artist's Concept

    NASA Technical Reports Server (NTRS)

    2007-01-01

    This artist's conception of NASA's Mars Science Laboratory portrays use of the rover's ChemCam instrument to identify the chemical composition of a rock sample on the surface of Mars.

    ChemCam is innovative for planetary exploration in using a technique referred to as laser breakdown spectroscopy to determine the chemical composition of samples from distances of up to about 8 meters (25 feet) away. ChemCam is led by a team at the Los Alamos National Laboratory and the Centre d'Etude Spatiale des Rayonnements in Toulouse, France.

    Mars Science Laboratory, a mobile robot for investigating Mars' past or present ability to sustain microbial life, is in development at NASA's Jet Propulsion Laboratory for a launch opportunity in 2009. The mission is managed by JPL, a division of the California Institute of Technology, Pasadena, Calif., for the NASA Science Mission Directorate, Washington.

  3. Dynamique sub-picoseconde de l'interaction laser de puissance agrégats de gaz rare: emission intense de rayons X et production d'ions multichargés

    NASA Astrophysics Data System (ADS)

    Prigent, C.; Adoui, L.; Dreuil, S.; Gauthier, J. C.; Gobert, O.; Lamour, E.; Meynadier, P.; Normand, D.; Perdrix, M.; Rozet, J.-P.; Vernhet, D.

    2003-06-01

    Lors de campagnes d'expériences réalisées sur le Laser Ultra Court Accordable du CEA/Saclay, nous avons étudié le rayonnement X, tant qualitativement (spectroscopie et énergie moyenne des photons) que quantitativement (taux absolus et lois d'évolution), émis lors de l'interaction d'un jet effusif d'agrégats de gaz rare (Ar, Kr, Xe comprenant entre 10^4 et 10^6 atome/agrégat) avec un laser femtoseconde de puissance (éclairement jusqu'à quelques 10^{17} W/cm^2). Les résultats présentés dans ce manuscrit sont uniquement dédiés aux agrégats d'Ar pour lesquels nous avons observé un rayonnement X issu d'ions fortement multichargés (jusqu'à l'Ar^{16+}) présentant des lacunes en couches K. La technique de spectroscopie X utilisée a permis de déterminer pour la première fois des taux absolus ainsi que les lois d'évolution de l'émission X en fonction de l'ensemble des paramètres gouvernant l'interaction (intensité, polarisation, longueur d'onde et durée du pulse laser aussi bien que taille, densité et numéro atomique des agrégats).

  4. Interdire aux enfants et aux adolescents de moins de 18 ans l’accès aux établissements commerciaux de bronzage

    PubMed Central

    Taddeo, Danielle; Stanwick, Richard

    2012-01-01

    RÉSUMÉ Le nombre de mélanomes cutanés malins a plus que triplé depuis 35 ans. Puisque les dommages sont cumulatifs, l’exposition aux rayonnements ultraviolets tôt dans la vie accroît le risque, qui augmente davantage avec l’utilisation de sources artificielles de rayonnements ultraviolets. Il peut falloir des années pour évaluer les répercussions et l’étendue complètes des dommages causés par le bronzage artificiel à longueur d’année, compte tenu de la longue période de latence de la plupart des cancers de la peau. Les adolescents fréquentent souvent les salons de bronzage, les filles s’y rendant davantage et de manière soutenue. L’industrie du bronzage conteste la classification de cancérigène physique de groupe 1 qu’attribuent au bronzage artificiel l’Organisation mondiale de la santé et le Centre international de recherche sur le cancer. Les salons de bronzage cherchent à établir et à maintenir une clientèle chez les adolescents. Par conséquent, la Société canadienne de pédiatrie s’ajoute à d’autres organismes de santé réputés pour appuyer l’interdiction des établissements commerciaux de bronzage aux enfants et adolescents de moins de 18 ans.

  5. Ion-Atom and Atom-Atom Collisional Processes and Modeling of Stellar Atmospheres

    NASA Astrophysics Data System (ADS)

    Mihajlov, A. A.; Ignjatovic, Lj. M.; Sreckovic, V. A.; Dimitrijevic, M. S.; Dimitrijevic, M. S.

    2015-09-01

    We report the results obtained in our previous works on the influence of two groups of collisional processes (ion--atom and atom--atom) on the optical and kinetic properties of weakly ionised plasma. The first group includes radiative processes of the photodissociation/association type and radiative charge exchange, the second one -- chemi-ionisation/recombination processes. The effect of the radiative processed is assessed by comparing their intensities with those of the known competing processed in application to the solar photosphere and to the photospheres of DB white dwarfs. The studied chemi-ionisation/recombination processes are considered from the viewpoint of their influence on the populations of the excited states of the hydrogen atom (the Sun and an M-type red dwarf with an effective temperature of 3800~K) and helium atom (DB white dwarfs). The effect of these processes on the populations of the excited states of the hydrogen atom has been studied using the PHOENIX code, which generates the model of the considered atmosphere. The reported results demonstrate the unquestionable influence of the considered radiative and chemi- ionisation/recombination processes on the optical properties and on the kinetics of the weakly ionised layers in stellar atmospheres. It can be expected that the reported results will be a sufficient reason for including these processes in the models of stellar atmospheres.

  6. Radiographer Delivered Fluoroscopy Reduces Radiation Exposure During Endoscopic Urological Procedures

    PubMed Central

    Hennessey, DB; Young, M; Pahuja, A

    2016-01-01

    Introduction The 1999 Ionising Radiation Regulations recommend that medical professionals using ionising radiation should aim to keep exposure as ‘low as reasonably practicable’. Urologists regularly use fluoroscopy during endoscopic surgical procedures. In some institutions, this is delivered by a radiographer whereas in others, it is delivered by the urological surgeon. Objectives To determine if radiographer-delivered fluoroscopy can reduce the exposure to ionising radiation during urological procedures. Methods An analysis of 395 consecutive patients, who underwent endoscopic urological procedures requiring fluoroscopy, was performed simultaneously across two institutions, over a 4 month period. 321 patients were matched and included in the analysis. Results Radiographer delivered fluoroscopy was associated with reduced ionising radiation exposure for retrograde pyelography procedures ED 0.09626 vs. 1.323 mSev, p= 0.0003, and endoscopic stone surgeries ED 0.3066 Vs. 0.5416 mSev, p=0.0039, but not for ureterorenoscopic stone surgeries 0.4880 vs. 0.2213 mSev, p=0.8292. Conclusion Radiographer delivered fluoroscopy could reduce the patient’s exposure to ionising radiation for some urological procedures. PMID:27158158

  7. Radiation-MHD Simulations of Pillars and Globules in HII Regions

    NASA Astrophysics Data System (ADS)

    Mackey, J.

    2012-07-01

    Implicit and explicit raytracing-photoionisation algorithms have been implemented in the author's radiation-magnetohydrodynamics code. The algorithms are described briefly and their efficiency and parallel scaling are investigated. The implicit algorithm is more efficient for calculations where ionisation fronts have very supersonic velocities, and the explicit algorithm is favoured in the opposite limit because of its better parallel scaling. The implicit method is used to investigate the effects of initially uniform magnetic fields on the formation and evolution of dense pillars and cometary globules at the boundaries of HII regions. It is shown that for weak and medium field strengths an initially perpendicular field is swept into alignment with the pillar during its dynamical evolution, matching magnetic field observations of the ‘Pillars of Creation’ in M16. A strong perpendicular magnetic field remains in its initial configuration and also confines the photoevaporation flow into a bar-shaped, dense, ionised ribbon which partially shields the ionisation front.

  8. Characterisation of a track structure imaging detector.

    PubMed

    Casiraghi, M; Bashkirov, V A; Hurley, R F; Schulte, R W

    2015-09-01

    The spatial distribution of radiation-induced ionisations in sub-cellular structures plays an important role in the initial formation of radiation damage to biological tissues. Using the nanodosimetry approach, physical characteristics of the track structure can be measured and correlated to DNA damage. In this work, a novel nanodosimeter is presented, which detects positive ions produced by radiation interacting with a gas-sensitive volume in order to obtain a high resolution image of the radiation track structure. The characterisation of the detector prototype was performed and different configurations of the device were tested by varying the detector cathode material and the working gas. Preliminary results show that the ionisation cluster size distribution can be obtained with this approach. Further work is planned to improve the detector efficiency in order to register the complete three-dimensional track structure of ionising radiation. PMID:25877534

  9. Nanodosimetric track structure in homogeneous extended beams.

    PubMed

    Conte, V; Moro, D; Colautti, P; Grosswendt, B

    2015-09-01

    Physical aspects of particle track structure are important in determining the induction of clustered damage in relevant subcellular structures like the DNA and higher-order genomic structures. The direct measurement of track-structure properties of ionising radiation is feasible today by counting the number of ionisations produced inside a small gas volume. In particular, the so-called track-nanodosimeter, installed at the TANDEM-ALPI accelerator complex of LNL, measures ionisation cluster-size distributions in a simulated subcellular structure of dimensions 20 nm, corresponding approximately to the diameter of the chromatin fibre. The target volume is irradiated by pencil beams of primary particles passing at specified impact parameter. To directly relate these measured track-structure data to radiobiological measurements performed in broad homogeneous particle beams, these data can be integrated over the impact parameter. This procedure was successfully applied to 240 MeV carbon ions and compared with Monte Carlo simulations for extended fields. PMID:25848108

  10. Electron transport in CF3I and CF3I-N2 mixtures

    NASA Astrophysics Data System (ADS)

    Kawaguchi, Satoru; Satoh, Kohki; Itoh, Hidenori

    2014-04-01

    Electron collision cross sections for CF3I are estimated using the electron swarm method. Electron drift velocity, effective ionisation coefficient, and longitudinal diffusion coefficient in CF3I are calculated using Monte Carlo method, and the calculated electron transport coefficients are compared with those measured. Calculated electron drift velocity agrees with measured data within the difference of 6% below 1600 Td, and calculated effective ionisation coefficient agrees with measured data within the difference of 10% above 460 Td. Further, those swarm parameters in CF3I-N2 mixtures are calculated, and calculated values of electron drift velocity and effective ionisation coefficient agree well with measured data in CF3I-N2 mixtures. This confirms the validity of the estimated set.

  11. Evaluation of the relative TL efficiency of the thermoluminescent detectors to heavy charged particles.

    PubMed

    Sądel, M; Bilski, P; Swakoń, J; Weber, A

    2016-01-01

    The relative thermoluminescence efficiency, η, is in general not constant but depends on ionisation density. Evaluation of the η is therefore important especially for correct interpretation of measurements of densely ionising radiation doses in proton radiotherapy or in space dosimetry. The correct determination of the η is not always straightforward especially when more strongly ionising radiation is to be measured. In the present work, the process of calculation of the η based on two kinds of heavy charged particles was studied. Several factors which may influence the value of the η and their significance for the final result were discussed. These include for example non-uniform deposition of the dose within the detector volume, self-attenuation of thermoluminescent light, choice of the reference radiation, etc. The presented approach was applied to the experimental results of η of LiF:Mg,Ti detectors irradiated with two kinds of heavy charged particles, protons and alpha particles. PMID:25656042

  12. Track nanodosimetry of 20-MeV protons at 20 nm.

    PubMed

    Conte, V; Colautti, P; De Nardo, L; Ferretti, A; Poggi, M; Moro, D; Lombardi, M; Tornielli, G; Grosswendt, B

    2011-02-01

    Track nanodosimetry is the theoretical and experimental research which studies the stochastic aspects of ionisation yield produced by ionising particles in nanometric target volumes, positioned at different distances from the primary particle track. The STARTRACK experimental set-up, mounted on the +50° beam line at the Tandem-Alpi particle accelerator of Legnaro National Laboratories, has been conceived to give an experimental basis to nanodosimetric calculations. STARTRACK is a detection system able to measure the ionisation cluster-size distributions in a 20 nm propane site, by counting the electrons set in motion by different ion tracks, with the resolution of one electron. The 'sensitive volume' SV can be moved at different distances from the primary particle track (different impact parameter). Distributions of 20-MeV protons have been measured and compared with Monte Carlo calculations. PMID:21127036

  13. Energetic particle influences in Earth's atmosphere

    NASA Astrophysics Data System (ADS)

    Aplin, Karen; Harrison, R. Giles; Nicoll, Keri; Rycroft, Michael; Briggs, Aaron

    2016-04-01

    Energetic particles from outer space, known as galactic cosmic rays, constantly ionise the entire atmosphere. During strong solar storms, solar energetic particles can also reach the troposphere and enhance ionisation. Atmospheric ionisation generates cluster ions. These facilitate current flow in the global electric circuit, which arises from charge separation in thunderstorms driven by meteorological processes. Energetic particles, whether solar or galactic in origin, may influence the troposphere and stratosphere through a range of different mechanisms, each probably contributing a small amount. Some of the suggested processes potentially acting over a wide spatial area in the troposphere include enhanced scavenging of charged aerosol particles, modification of droplet or droplet-droplet behavior by charging, and the direct absorption of infra-red radiation by the bending and stretching of hydrogen bonds inside atmospheric cluster-ions. As well as reviewing the proposed mechanisms by which energetic particles modulate atmospheric properties, we will also discuss new instrumentation for measurement of energetic particles in the atmosphere.

  14. Environmentally friendly plasma-based surface engineering technologies

    NASA Astrophysics Data System (ADS)

    Drenik, A.; Mozetic, M.; Vesel, A.; Cvelbar, U.

    2010-01-01

    Weakly ionised reactive plasmas are characterised by a very low degree of ionization, which rarely exceeds the order of 10-4, and by a very high degree of dissociation, which often reaches values above 50%. Thus the most numerous plasma species are free neutral atoms originated from the dissociation of the source gas molecules. Neutral atoms are chemically very reactive species, which makes such plasma suitable for material processing. At the same time the neutral atoms have a low kinetic energy and therefore they cannot penetrate into the bulk material, so their effect is restricted to the topmost atomic layers of the material surface hence weakly ionised, reactive plasmas are suitable for surface engineering. Here we present examples of weakly ionised plasma applications as environmentally friendly alternatives to processes that otherwise utilise aggressive chemicals and produce toxic waste.

  15. Modeling small galaxies during the Epoch of Reionisation

    NASA Astrophysics Data System (ADS)

    Trebitsch, M.; Blaizot, J.; Rosdahl, J.

    2015-12-01

    Small galaxies are thought to be the main contributors to the ionising budget of the Universe before reionisation was complete. There have been a number of numerical studies trying to quantify their ionising efficiency through the escape fraction fesc. While there is a clear trend that fesc is higher for smaller haloes, there is a large scatter in the distribution of fesc for a single halo mass. We propose that this is due to the intrinsic burstiness of star formation in low mass galaxies. We performed high resolution radiative hydrodynamics simulations with ramsesrt to model the evolution of three galaxies and their ionising efficiency. We found that the variability of fesc follows that of the star formation rate. We then discuss the consequences of this variability on the observability of such galaxies by JWST.

  16. Physics and chemistry in glow dielectric barrier discharges

    NASA Astrophysics Data System (ADS)

    Massines, Françoise

    2001-10-01

    Atmospheric pressure glow discharge (APGD) are of great interest for application in gas chemistry, sterilization, surface activation or thin film deposition. But the development of a new process based on this discharge needs a clear understanding of the discharge physics and chemistry. The aim of this work is to contribute to that goal. One difficulty is the large variety of discharges called APGD. Then the first point of this talk will consist on a quick description of the different APGD families. This overview will be limited to dielectric barrier glow discharges. Then, we will focussed on those due to a Townsend breakdown. The analysis of their working domain in helium and in nitrogen shows that a lot of seed electrons are necessary to turn on the discharge through a Townsend breakdown. The main mechanism leading to these seed electrons depends (i) on the life time of the gas metastables compared to the delay between two consecutive discharges (ii) on the maximum ionisation level which can be reached without transition to FD. In helium, the origin of the seed electrons is mainly the electrons created by direct ionisation and Penning ionisation during a discharge or at the end of it, trapped in the positive column and still present in the gas when the following discharge is turned on. In nitrogen, the seed electrons are created by Penning ionisation just before the breakdown. Then in helium, the time between two discharges has to be short enough and a positive column is necessary as well as the presence of helium metastables. In N2, metastable density just before the breakdown is a dominant parameter. Moreover, the density of N2 molecules and then the gas temperature, is also important in order to maintain a large contribution of Penning ionisation compared to direct electronic ionisation. In all the gases, the metastables control the discharge development and then play an important role in the gas chemistry.

  17. The missing link: Tracing molecular gas in the outer filament of Centaurus A

    NASA Astrophysics Data System (ADS)

    Morganti, Raffaella; Oosterloo, Tom; Oonk, J. B. Raymond; Santoro, Francesco; Tadhunter, Clive

    2016-08-01

    We report the detection, using observations of the CO(2-1) line performed with the Atacama Pathfinder EXperiment (APEX), of molecular gas in the region of the outer filament of Centaurus A, a complex region known to show various signatures of an interaction between the radio jet, an H i cloud, and ionised gas filaments. We detect CO(2-1) at all observed locations, which were selected to represent regions with very different physical conditions. The H2 masses of the detections range between 0.2 × 106 and 1.1 × 106M⊙, for conservative choices of the CO to H2 conversion factor. Surprisingly, the stronger detections are not coincident with the H i cloud, but instead are in the region of the ionised filaments. We also find variations in the widths of the CO(2-1) lines throughout the region, with broader lines in the region of the ionised gas, i.e. where the jet-cloud interaction is strongest, and with narrow profiles in the H i cloud. This may indicate that the molecular gas in the region of the ionised gas has the momentum of the jet-cloud interaction encoded in it, in the same way as the ionised gas does. These molecular clouds may therefore be the result of very efficient cooling of the down-stream gas photo- or shock-ionised by the interaction. On the other hand, the molecular clouds with narrower profiles, which are closer to or inside the H i cloud, could be pre-existing cold H2 cores which manage to survive the effects of the passing jet.

  18. Dose measurements in pulsed radiation fields with commercially available measuring components.

    PubMed

    Friedrich, Sabrina; Hupe, Oliver

    2016-03-01

    Dose measurements in pulsed radiation fields with dosemeters using the counting technique are known to be inappropriate. Therefore, there is a demand for a portable device able to measure the dose in pulsed radiation fields. As a detector, ionisation chambers seem to be a good alternative. In particular, using a secondary standard ionisation chamber in combination with a reliable charge-measuring system would be a good solution. The Physikalisch-Technische Bundesanstalt (PTB) uses secondary standard ionisation chambers in combination with PTB-made measuring electronics for dose measurements at its reference fields. However, for general use, this equipment is too complex. For measurements on-site, a mobile special electronic system [Hupe, O. and Ankerhold, U. Determination of ambient and personal dose equivalent for personnel and cargo security screening. Radiat. Prot. Dosim. 121: (4), 429-437 (2006)] has been used successfully. Still, for general use, there is a need for a much simpler but a just as good solution. A measuring instrument with very good energy dependence for H*(10) is the secondary standard ionisation chamber HS01. An easy-to-use and commercially available electrometer for measuring the generated charges is the UNIDOS by PTW Freiburg. Depending on the expected dose values, the ionisation chamber used can be selected. In addition, measurements have been performed by using commercially available area dosemeters, e.g. the Mini SmartION 2120S by Thermo Scientific, using an ionisation chamber and the Szintomat 6134 A/H by Automess, using a scintillation detector. PMID:26056377

  19. Development of a Primary Standard for Calibration of [18F]FDG Activity Measurement Systems

    NASA Astrophysics Data System (ADS)

    Capogni, M.; DeFelice, P.; Fazio, A.; Simonelli, F.; D'Ursi, V.; Pecorale, A.; Giliberti, C.; Abbas, K.

    2006-05-01

    The 18F national primary standard was developed by the INMRI-ENEA using the 4πβ Liquid Scintillation Spectrometry Method with 3H-Standard Efficiency Tracing. Measurements were performed at JRCIspra under a scientific collaboration between the Institute for Health and Consumer Production, the Amersham Health and the National Institute for Occupational Safety and Prevention (ISPESL). The goal of the work was to calibrate, with minimum uncertainty, the INMRI-ENEA transfer standard portable well-type ionisation chamber as well as other JRC-Ispra and Amersham Health reference Ionising Chambers used for FDG activity measurement.

  20. Basic radiation protection training for nurses and paramedical personnel: Belgian experience and future perspectives.

    PubMed

    Clarijs, T; Coeck, M; Van Bladel, Lodewijk; Fremout, An

    2015-07-01

    When using ionising radiation for medical diagnosis or treatment of patients, understanding of relevant radiation protection principles and issues is indispensable. In Belgium, nurses and paramedical staff are required to acquire knowledge for protecting the patient against the detrimental effects of ionising radiation by means of a vocational training course. The experience with and challenges for this training course are presented here from a lecturer's point of view, together with a proposal for a future approach that harmonises the training content, its level and quality, according to European recommended standards. PMID:25821209

  1. Nanodosimetry of electrons: analysis by experiment and modelling.

    PubMed

    Bantsar, A; Pszona, S

    2015-09-01

    Nanodosimetry experiments for high-energy electrons from a (131)I radioactive source interacting with gaseous nitrogen with sizes on a scale equivalent to the mass per area of a segment of DNA and nucleosome are described. The discrete ionisation cluster-size distributions were measured in experiments carried out with the Jet Counter. The experimental results were compared with those obtained by Monte Carlo modelling. The descriptors of radiation damages have been derived from the data obtained from ionisation cluster-size distributions. PMID:25971347

  2. Track nanodosimetry of an alpha particle.

    PubMed

    De Nardo, L; Colautti, P; Baek, W Y; Grosswendt, B; Alkaa, A; Ségur, P; Tornielli, G

    2002-01-01

    Experimental measurements and calculations are described of ionisation distributions in propane wall-less gas cavities of about 20 nm simulated size, performed at different distances from a 244Cm alpha particle track. Ionisation events are detected one by one by collecting electrons from the sensitive volume and by separating them with a drift column. Experimental results and Monte Carlo calculations indicate that, in the delta ray cloud, conditional probability curves, average cluster size and the ratio of second moment above first moment of the cluster distribution are invariant with track distance. PMID:12194323

  3. On the atomic state densities of plasmas produced by the ``torche à injection axiale''

    NASA Astrophysics Data System (ADS)

    Jonkers, J.; Vos, H. P. C.; van der Mullen, J. A. M.; Timmermans, E. A. H.

    1996-04-01

    The atomic state densities of helium and argon plasmas produced by the microwave driven plasma torch called the "torche à injection axiale" are presented. They are obtained by absolute line intensity measurements of the excited states and by applying the ideal gas law to the ground state. It will be shown that the atomic state distribution function (ASDF) does not obey the Saha-Boltzmann law: the ASDF cannot be described by one temperature. From the shape of the ASDF it can be concluded that the plasma is ionising. By extrapolating the measured state densities towards the ionisation limit, a minimum value of the electron density can be determined.

  4. The physical basis of the release curve for RIB foil targets

    SciTech Connect

    Bennett, J R J

    1999-04-26

    Both diffusion and effusion in radioactive ion beam foil targets can be described mathematically by Fick's Law of diffusion. An approximate solution to the equation with the appropriate boundary conditions is presented for the RIST geometry target. This solution is expressed in terms of the physical and geometrical properties of the target and ioniser: the diffusion constant of the foil material, the conductance and the dimensions of the target and ioniser. The results of fitting the equation to measured data are shown. The equation can be used to optimize the design of targets for different radioactive ion beams.

  5. Removal of Polysorbate 80 by complexation prior to LC-MS analysis.

    PubMed

    Jäpelt, Kristina B; Johnsen, Lea Giørtz; Christensen, Jan H

    2016-03-01

    The presence of Polysorbate 80 in samples can challenge liquid chromatography-electrospray ionisation mass spectrometry (LC-ESI-MS) analysis as it is easily ionised and detected. In this study, we demonstrate that interference from Polysorbate 80 can be reduced by complexation with a metal ion followed by precipitation by thiocyanate. The precipitation procedure was tested on a mixture of low molecular weight compounds (e.g. amino acids and non-amino organic acids) and it was shown that none of the tested compounds were precipitated. PMID:26894763

  6. The Collinear Resonance Ionization Spectroscopy (CRIS) experimental setup at CERN-ISOLDE

    NASA Astrophysics Data System (ADS)

    Cocolios, T. E.; Al Suradi, H. H.; Billowes, J.; Budinčević, I.; de Groote, R. P.; De Schepper, S.; Fedosseev, V. N.; Flanagan, K. T.; Franchoo, S.; Garcia Ruiz, R. F.; Heylen, H.; Le Blanc, F.; Lynch, K. M.; Marsh, B. A.; Mason, P. J. R.; Neyens, G.; Papuga, J.; Procter, T. J.; Rajabali, M. M.; Rossel, R. E.; Rothe, S.; Simpson, G. S.; Smith, A. J.; Strashnov, I.; Stroke, H. H.; Verney, D.; Walker, P. M.; Wendt, K. D. A.; Wood, R. T.

    2013-12-01

    The CRIS setup at CERN-ISOLDE is a laser spectroscopy experiment dedicated to the high-resolution study of the spin, hyperfine structure and isotope shift of radioactive nuclei with low production rates (a few per second). It combines the Doppler-free resolution of the in-flight collinear geometry with the high detection efficiency of resonant ionisation. A recent commissioning campaign has demonstrated a 1% experimental efficiency, and as low as a 0.001% non-resonant ionisation. The current status of the experiment and its recent achievements with beams of francium isotopes are reported. The first identified systematic effects are discussed.

  7. Non-volatile analysis in fruits by laser resonant ionization spectrometry: application to resveratrol (3,5,4'-trihydroxystilbene) in grapes

    NASA Astrophysics Data System (ADS)

    Montero, C.; Orea, J. M.; Soledad Muñoz, M.; Lobo, R. F. M.; González Ureña, A.

    A laser desorption (LD) coupled with resonance-enhanced multiphoton ionisation (REMPI) and time-of-flight mass spectrometry (TOFMS) technique for non-volatile trace analysis compounds is presented. Essential features are: (a) an enhanced desorption yield due to the mixing of metal powder with the analyte in the sample preparation, (b) a high resolution, great sensitivity and low detection limit due to laser resonant ionisation and mass spectrometry detection. Application to resveratrol content in grapes demonstrated the capability of the analytical method with a sensitivity of 0.2 pg per single laser shot and a detection limit of 5 ppb.

  8. [Mitral valvuloplasty during the 4th month of pregnancy. Fetal protection with a lead mantle].

    PubMed

    Drobinski, G; Fraboulet, P; Montalescot, G; Moussallem, N; Coutte, R; Artigou, J Y; Grosgogeat, Y

    1991-02-01

    A 27 year old woman who had undergone closed heart surgical commissurotomy 10 years previously, underwent percutaneous mitral valvuloplasty during the fourth month of her pregnancy. Despite significant valvular thickening with calcification, the balloon dilatation led to an increase in valve surface area from 1.1 to 2 cm2 with no complications and with relief of the pulmonary hypertension. Foetal protection against ionising radiation was assured by a lead mantle completely surrounding the patient's abdomen. This protection reduced irradiation of the pelvic region to 0.5 milliSievert which corresponds to 1/100 of the permitted irradiation of pregnant women professionally exposed to ionising radiation. PMID:2021286

  9. Peculiarities of high electric field conduction in p-type diamond

    NASA Astrophysics Data System (ADS)

    Mortet, V.; Trémouilles, D.; Bulíř, J.; Hubík, P.; Heller, L.; Bedel-Pereira, E.; Soltani, A.

    2016-04-01

    The electrical properties of chemical vapour deposited p-type epitaxial diamond layers are studied in high electric field conditions. The quasi-static current-voltage characteristics have been measured using transmission-line pulse method with 100 ns pulses. Reproducible impurity impact ionization avalanche breakdown occurs at a critical electrical field in the range of 100-200 kV cm-1 depending on the acceptor concentration and temperature, leading to complete ionisation of neutral impurities. The current-voltage characteristics exhibit an S-shape with the bi-stable conduction characteristic of impurity impact ionisation.

  10. Role of local coordination geometry in charge transfer in YBa_2Cu_3O_{7-δ} superconductors

    NASA Astrophysics Data System (ADS)

    Gupta, Michèle; Gupta, Raju P.

    1992-02-01

    Although the mechanism responsible for the high T_c superconductivity is still unknown, it is nevertheless clear that superconductivity in the hole-doped materials depends sensitively on the number of holes, C_h, per CuO2 plane. A correlation between C_h and T_c has been established. In this paper we present examples of the critical dependence of the charge transfer, and hence the value of C_h, on the crystallographic characteristics and particularly on the local coordination geometry of the chain Cu atom. Electronic structure investigation of YBa2Cu3O{6.5} have been performed for this purpose using three models for the oxygen ordering. We obtain a sizeable charge transfer of sim 0.16 electron/CuO2 only in the alternate chain model in which one chain in two remains intact as in YBa2Cu3O7 while in the tetragonal structure or in the identical chain model, in which all chains along the b-axis are broken, a negligible charge transfer is obtained. These results show that the order-disorder phenomena of the chain site oxygen atoms in YBa2Cu3O{7-δ} play a crucial role in charge transfer, hole creation in the CuO2 planes, and superconductivity. Bien que le mécanisme responsable de la supraconductivité à haute T_c n'ait pas encore été élucidé, il est néanmoins établi que la supraconductivité des matériaux dopés par trous dépend de façon sensible du nombre de trous, C_h, par plan CuO2. Une corrélation entre C_h et T_c a été mise en évidence. Dans cet article nous montrons à l'aide de divers exemples que les transferts de charge et la valeur de C_h dépendent des caractéristiques cristallographiques et en particulier de la coordination et de la géométrie locale des atomes de cuivre des chaînes. Des calculs de structure électronique du composé YBa2Cu3O{6.5} ont été réalisés à cet effet en utilisant trois modèles différents pour l'ordre des atomes d'oxygène. Nous obtenons un transfert de charge substantiel de sim 0.16 e^- par plan CuO2

  11. Description matricielle de l'anisotropie de la transition inter-sous-bande d'une structure à multi-puits quantiques

    NASA Astrophysics Data System (ADS)

    Boucher, Y. G.; Le Rouzo, J.; Ribet, I.; Haïdar, R.; Guérineau, N.

    2006-10-01

    Dans un puits quantique, les transitions radiatives inter-sous-bande sont telles que seule la composante du champ électrique parallèle à l'axe de croissance est affectée. Cette spécificité confère à l'absorption un caractère foncièrement anisotrope. Nous établissons la matrice de transfert d'une structure à multi-puits quantiques en assimilant chaque puits à une couche mince anisotrope uniaxe. À l'anisotropie intrinsèque (règles de sélection) se superpose une anisotropie structurelle (biréfringence de forme). Les symétries du système permettent néanmoins de découpler les états de polarisation (s) et (p).

  12. Italian Exposition

    SciTech Connect

    2006-10-11

    Le DG parle dans son allocution à l'occasion de l'exposition (suivi d'une visite)de la contribution du Cern à la création d'une espace de la technologie européenne. Il parle de la manière comment organiser des formes fructueuses de coopération et coordination internationales dans ce domaine. "Afin de renforcer encore notre relation avec l'industrie et intensifier le transfert de la technologie nous proposerons au ministre de recherche de poursuivre dans le cadre du programme EUREKA ensemble avec les industries des programmes concrètes." Le ministre italien prend ensuite la parole.

  13. Détection homodyne pour mémoires holographiques à stockage bit à bit

    NASA Astrophysics Data System (ADS)

    Maire, G.; Pauliat, G.; Roosen, G.

    2006-10-01

    Les mémoires holographiques à stockage bit à bit sont une alternative intéressante à l'approche holographique conventionnelle par pages de données du fait de leur architecture optique simplifiée. Nous proposons et validons ici une procédure de lecture adaptée à de telles mémoires et basée sur une détection homodyne de l'amplitude diffractée par les hologrammes. Ceci permet d'augmenter la quantité de signal utile détecté et s'avère donc prometteur pour accroître le taux de transfert de données de ces mémoires.

  14. Italian Exposition

    ScienceCinema

    None

    2011-04-25

    Le DG parle dans son allocution à l'occasion de l'exposition (suivi d'une visite)de la contribution du Cern à la création d'une espace de la technologie européenne. Il parle de la manière comment organiser des formes fructueuses de coopération et coordination internationales dans ce domaine. "Afin de renforcer encore notre relation avec l'industrie et intensifier le transfert de la technologie nous proposerons au ministre de recherche de poursuivre dans le cadre du programme EUREKA ensemble avec les industries des programmes concrètes." Le ministre italien prend ensuite la parole.

  15. Évolution de l'occupation des terres et ressources en eau en région Méditerranéenne karstique

    NASA Astrophysics Data System (ADS)

    Rambal, S.

    1987-09-01

    A computer model, with explicit descriptions for the major processes involved in the transfert of water in the soil-plant system at a local level, formed a basis for simulating the consequences of land-use change on streamflow in a 35 km 2 karstic catchment near Montpellier, southern France. Natural vegetation, occupying more than 95% of the total surface, is divided in four types according to their tree covers. In condition of lithologic homogeneity, these types can be used as hydrologic units. Computed streamflow for existing land-use corresponds with recorded data on both the monthly and annual scales. Land-use changes, due to the natural evolution of the vegetation from 1946 to 1979, produced a 80 mm reduction in streamflow for average rainfall conditions (1200 mm).

  16. Oxygen hole pairing in CuO2 planes : a quasi-one dimensional case

    NASA Astrophysics Data System (ADS)

    Feinberg, D.; Avignon, M.; Boiron, M.; Chakraverty, B. K.

    A possible mechanism of pairing of oxygen holes produced on doping is investigated. These holes are formed due to strong correlation energy on copper sites. In a simplified CuO2-sheet band structure, they are showed to take place in a narrow p-oxygen band originating from the broadening of a non-bonding p-oxygen level by direct O-O transfer. Such a band shows a quasi-one-dimensional density of states N (E) ˜ E- 1/2, which strongly enhances BCS-type pairing. Tc is evaluated for both s and d pairing and varies as tλ 2 where λ is the coupling constant and t the O-O transfer integral. On examine la possibilité d'appariement de trous sur les oxygènes, produits lors du dopage. Ces trous sont formés du fait des fortes corrélations sur les sites de cuivre. Dans une structure de bande simplifiée, pour les plans CuO2, on montre qu'ils se forment dans une étroite bande p d'oxygène issue de l'élargissement d'un niveau p non-liant par transfert direct O-O. Une telle bande possède une densité d'états quasi-unidimensionnelle N (E) ˜ E-1/2, ce qui favorise fortement l'appariement de type BCS. Tc est évaluée dans le cas d'un appariement s et d et varie comme tλ2 où λ est la constante de couplage et t l'intégrale de transfert O-O.

  17. Etude des émissions radio aurorales de Saturne, modélisation et aurores UV

    NASA Astrophysics Data System (ADS)

    Lamy, Laurent

    2008-09-01

    Cette thèse porte sur l'étude du rayonnement radio auroral kilométrique de Saturne (SKR pour Saturn Kilometric Radiation) observé de façon quasi-continue par les antennes radio de la sonde Cassini depuis son entrée en orbite autour de Saturne en juillet 2004. Comme les rayonnements radio auroraux des autres planètes magnétisées, le SKR est généré sur des lignes de champ magnétique de haute latitude prés des pôles magnétiques. Tirant parti de plusieurs années d'observations, les propriétés macroscopiques du SKR (spectre, polarisation, conjuguaison des sources de chaque hémisphère, mode d'émission) sont déduites par une analyse statistique. Elles montrent en particulier que les caractéristiques de l'émission dépendent fortement de la position de l'observateur. Ceci est une conséquence directe de l'anisotropie du SKR qui engendre de forts effets de visibilité, visibles dans les cartes d'intensité temps-fréquence (arcs, régions d'invisibilité de l'émission). La simulation de ces effets de visibilité apporte de nouvelles contraintes sur les propriétés microscopiques des sources (énergie et distribution des électrons auroraux). Le SKR est connu pour être modulé à une période variable. Une analyse de la variation de cette période radio sur plusieurs années révèle des oscillations à court terme de l'ordre de 20-30 jours dont l'origine est attribuée à la variation de la vitesse caractéristique du vent solaire au niveau de Saturne. Une étude parallèle du rayonnement auroral kilométrique terrestre (AKR), observé lors du survol de la Terre par Cassini en août 1999, met en évidence la découverte d'une modulation diurne semblable à celle du SKR. Enfin, la technique de goniopolarimétrie permet de faire de l'imagerie radio des sources du SKR. L'étude de leur distribution moyenne montre pour la première fois l'existence d'un ovale radio. La comparaison des images des sources du SKR avec celles des ovales auroraux (observ

  18. Experts workshop on the ecotoxicological risk assessment of ionizable organic chemicals: Towards a science-based framework for chemical assessment

    EPA Science Inventory

    There is a growing need to develop analytical methods and tools that can be applied to assess the environmental risks associated with charged, polar, and ionisable organic chemicals, such as those used as active pharmaceutical ingredients, biocides, and surface active chemicals. ...

  19. Science with the High Elevation Antarctic Terahertz Telescope

    NASA Astrophysics Data System (ADS)

    Burton, M. G.; Walsh, W.; Storey, J. W. V.; Ashley, M. C. B.; Walker, C.

    2006-08-01

    The proposed High Elevation Antarctic Terahertz Telescope (HEAT) is an instrument designed for the measurement of sub-mm spectral lines over regions several square degrees in size toward the Milky Way and Magellanic Clouds. By mapping as a function of Galactic position the size and mass distribution and internal velocity dispersion of interstellar clouds in the Galaxy in both atomic and molecular lines, HEAT will construct the first barometric map of the Galactic Plane. HEAT will also map the gas heating rate, the star formation rate and produce the first large scale Galactic images of the dominant cooling atomic cooling lines of carbon and nitrogen. balance, and evolution of molecular clouds in the Milky Way and distant star-forming galaxies. Since the ionisation potential of nitrogen is 14.5eV, the 1461.1319 GHz = 205.176µm line of [NII] arises from regions where hydrogen is ionised, and thus serves as an extinction-free probe of the Warm Ionised Medium (WIM). There is an observed nonlinear relationship between [CII] and [NII] emission (Bennett et al. 1994) on large scales. By observing a variety of UV-illuminated giant molecula clouds, compact and diffuse HII regions, and planetary nebulae in the 1461 GHz [NII] line at 700 times the spectral and angular resolution of satellite data, the [CII]/[NII] intensity ratio can be used as a probe to determine how much of the Galaxy's [CII] emission arises in ionised gas.

  20. Dynamic processes in active medium of small diameter gas discharge lasers

    NASA Astrophysics Data System (ADS)

    Schishov, S. I.

    2008-03-01

    Review of electrodynamics properties for gas discharge lasers of small diameter has been completed with consideration of inertia typical for ionisation processes and transient nature of electron diffusion from unipolar to ambipolar. Procedure for calculation of transfer function and elements of equivalent electrical circuit for substitution of gas discharge laser discharge space.

  1. Nonsequential Double Ionization of Atoms in Strong Laser Pulses

    NASA Astrophysics Data System (ADS)

    Prauzner-Bechcicki, J. S.; Sacha, K.; Eckhardt, B.; Zakrzewski, J.

    2007-10-01

    It is now possible to produce laser pulses with reproducible pulse shape and controlled carrier envelope phase. It is discussed how that can be explored in double ionisation studies. To this end we solve numerically the Schrödinger equation for a limited dimensionality model which nevertheless treats electron repulsion qualitatively correctly and allows to study correlation effects due to the Coulomb repulsion.

  2. Evolution of star formation conditions from high-redshift to low-redshift

    NASA Astrophysics Data System (ADS)

    Shirazi, Maryam

    2015-08-01

    There are some hints indicating extreme interstellar medium (ISM) conditions at high redshift e.g., harder ionsing radiation fields and higher electron densities. By analysing the ionisation state of galaxies using their [OIII]5007/[OII]3727 line ratios we recently showed that star-forming galaxies at z~ 1. 5 -- 3. 5 have higher ionisation parameters and higher gas densities relative to that of local galaxies with similar global properties (Shirazi et al. 2014). This means the intrinsic properties e.g., the density of star forming regions at high redshift is different from what we observe in the local Universe. Based on the distribution of galaxies in the BPT diagram, it is proposed that the transition to nearby like conditions happen at 0. 8 < z < 1. 5 (Kewley et al 2013). However, we do not know how star-forming regions of the intermediate redshift galaxies are compared to that of high redshift galaxies that have higher gas fractions and are close to the peak of star formation activity in the Universe. We use the unique capability of the MUSE to indirectly trace the ISM conditions at those redshifts. We measure the spatially-resolved ionisation parameter using [OIII ]5007/ [O II]3727 ratio and we measure the spatially resolved gas density using the [OII] 3727,3729 doublet. We probe the spatial distributions of the ionisation parameter and gas density and search for systematic differences between high, intermediate and low redshift galaxies in terms of their global galaxy properties.

  3. Radiosensitization of Aspergillus niger and Penicillium chrysogenum using basil essential oil and ionizing radiation for food decontamination.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Minimum Inhibitory Concentration (MIC) of basil oil, was determined for two pathogenic fungi of rice, Aspergillus niger and Penicillium chrysogenum. The antifungal activity of the basil oil in combination with ionising radiation was then investigated to determine if basil oil caused radiosensit...

  4. Triggered star formation in the environment of young massive stars

    NASA Astrophysics Data System (ADS)

    Gritschneder, Matthias; Naab, T.; Heitsch, F.; Burkert, A.

    Recent observations with the Spitzer Space Telescope show clear evidence that star formation takes place in the surrounding of young massive O-type stars, which are shaping their environment due to their powerful radiation and stellar winds. In this work we investigate the effect of ionising radiation of massive stars on the ambient interstellar medium (ISM): In particular we want to examine whether the UV-radiation of O-type stars can lead to the observed pillar-like structures and can trigger star formation. We developed a new implementation, based on a parallel Smooth Particle Hydrodynamics code (VINE), that allows an efficient treatment of the effect of ionising radiation from massive stars on their turbulent gaseous environment. Here we present first results at very high resolution. We show that ionising radiation can trigger the collapse of an otherwise stable molecular cloud. The arising structures resemble observed structures (e.g. the pillars of creation in the Eagle Nebula (M16) or the Horsehead Nebula B33). Including the effect of gravitation we find small regions that can be identified as formation places of individual stars. We conclude that ionising radiation from massive stars alone can trigger substantial star formation in molecular clouds.

  5. Towards measuring the ground state hyperfine splitting of antihydrogen - a progress report

    NASA Astrophysics Data System (ADS)

    Sauerzopf, C.; Capon, A. A.; Diermaier, M.; Dupré, P.; Higashi, Y.; Kaga, C.; Kolbinger, B.; Leali, M.; Lehner, S.; Rizzini, E. Lodi; Malbrunot, C.; Mascagna, V.; Massiczek, O.; Murtagh, D. J.; Nagata, Y.; Radics, B.; Simon, M. C.; Suzuki, K.; Tajima, M.; Ulmer, S.; Vamosi, S.; Gorp, S. van; Zmeskal, J.; Breuker, H.; Higaki, H.; Kanai, Y.; Kuroda, N.; Matsuda, Y.; Venturelli, L.; Widmann, E.; Yamazaki, Y.

    2016-12-01

    We report the successful commissioning and testing of a dedicated field-ioniser chamber for measuring principal quantum number distributions in antihydrogen as part of the ASACUSA hyperfine spectroscopy apparatus. The new chamber is combined with a beam normalisation detector that consists of plastic scintillators and a retractable passivated implanted planar silicon (PIPS) detector.

  6. Investigation of bromide's spectra by high resolution UV-laser

    NASA Astrophysics Data System (ADS)

    Zhang, Jin; Ma, Jian-guo

    2011-12-01

    Experimental investigation has been carried out for dissociation/ionisation of methyl bromide using time of flight mass spectrometer, then, the mass signals were assigned to H+, CHm+ (m= 0-3), iBr+ (i = 79, 81), and the main processes of multi-photon ionization and dissociation of CH3Br were given.

  7. Spectroscopy of the Pistol and Quintuplet stars in the Galactic centre

    NASA Astrophysics Data System (ADS)

    Moneti, A.; Blommaert, J. A. D. L.; Najarro, F.; Figer, D.; Stolovy, S.

    1999-03-01

    We present initial results of a spectroscopic study of the Pistol and of the cocoon stars in the Quintuplet Cluster. From ISOCAM CVF 5--17 μm spectroscopy of the field of the Pistol Star, we have discovered a nearly spherical shell of hot dust surrounding this star, a probable LBV. This shell is most prominent at λ >~ 12 μm, and its morphology clearly indicates that the shell is stellar ejecta. Emission line images show that most of the ionised material is along the northern border of this shell, and its morphology is very similar to that of the Pistol H ii region (Yusef-Zadeh & Morris, 1987). We thus confirm that the ionisation comes from very hot stars in the core of the Quintuplet Cluster. An SWS spectrum of the Pistol Nebula indicates a harder ionising radiation than could be provided by the Pistol Star, but which is consistent with ionisation from Wolf-Rayet stars in the Quintuplet Cluster. The CVF 5--17 μm spectra of the cocoon stars in the Quintuplet do not show any emission feature that could help elucidate their nature.

  8. Magnetic resonance imaging with gadolinium-DTPA enhancement in the differentiation of benign from neoplastic cord cavitation.

    PubMed

    Clarke, C E; Hawnaur, J; Prvulovich, E; Yuill, G M; Bannister, C M

    1990-03-01

    A patient with an extensive spinal cord glioma is presented. The lumbar mass and cervical cavity associated with the tumour were demonstrated by myelography and computed tomography. Magnetic resonance imaging provided greater detail than these conventional imaging modalities without exposure to ionising radiation and was of considerable additional value in the planning of surgery. PMID:2323169

  9. Determination of acrylamide in coffee and chocolate by pressurised fluid extraction and liquid chromatography-tandem mass spectrometry.

    PubMed

    Pardo, O; Yusà, V; Coscollà, C; León, N; Pastor, A

    2007-07-01

    A selective and sensitive procedure has been developed and validated for the determination of acrylamide in difficult matrices, such as coffee and chocolate. The proposed method includes pressurised fluid extraction (PFE) with acetonitrile, florisil clean-up purification inside the PFE extraction cell and detection by liquid chromatography (LC) coupled to atmospheric pressure ionisation in positive mode tandem mass spectrometry (APCI-MS-MS). Comparison of ionisation sources (atmospheric pressure chemical ionisation (APCI), atmospheric pressure photoionization (APPI) and the combined APCI/APPI) and clean-up procedures were carried out to improve the analytical signal. The main parameters affecting the performance of the different ionisation sources were previously optimised using statistical design of experiments (DOE). PFE parameters were also optimised by DOE. For quantitation, an isotope dilution approach was used. The limit of quantification (LOQ) of the method was 1 microg kg(-1) for coffee and 0.6 microg kg(-1) for chocolate. Recoveries ranged between 81-105% in coffee and 87-102% in chocolate. The accuracy was evaluated using a coffee reference test material FAPAS T3008. Using the optimised method, 20 coffee and 15 chocolate samples collected from Valencian (Spain) supermarkets, were investigated for acrylamide, yielding median levels of 146 microg kg(-1) in coffee and 102 microg kg(-1) in chocolate. PMID:17613050

  10. TRIMCAT, a TRIM interface for GARFIELD

    NASA Astrophysics Data System (ADS)

    Butterworth, J. E.; Barton, C. J.

    2009-04-01

    Garfield is a simulation code designed to model gaseous detectors and the properties of ionisation and electron drift. TRIM is a code designed to simulate the transport properties and ionisation effects of ions passing through matter. TRIMCAT is an extension module for Garfield which allows Garfield to interface with TRIM output files. Using this module, the two codes can be used in conjunction: TRIM simulates the ionisation properties of ions passing through detector components and Garfield simulates the electron cluster generation and transport properties in the detector gas volume. The TRIMCAT module has a considerably higher degree of accuracy than other methods of generating ionisation distributions in Garfield such as inputting an appropriate polynomial or using an existing interface with the SRIM stopping and range tables program. The results from the TRIMCAT module show a good correlation with existing data and it is foreseen that this software may be useful in many different situations. An example of the use of TRIMCAT, the design of the York Bragg Detector, is presented.

  11. Multiphoton time-delay spectroscopy using not transform-limited laser pulses

    NASA Astrophysics Data System (ADS)

    Cavalieri, Stefano; Materazzi, Marzia; Eramo, Roberto; Fini, Lorenzo; Giugni, Andrea

    2000-08-01

    We report on a two-photon resonant three-photon ionisation experiment performed on atomic barium with a sequence of two identical not transform-limited laser pulses in the weak field regime. We show that our results, obtained by a multimode nanosecond laser source, can be reproduced theoretically by using much shorter transform-limited pulses with the same spectral bandwidth.

  12. SDSS IV MaNGA - Spatially resolved diagnostic diagrams: A proof that many galaxies are LIERs

    NASA Astrophysics Data System (ADS)

    Belfiore, Francesco; Maiolino, Roberto; Maraston, Claudia; Emsellem, Eric; Bershady, Matthew A.; Masters, Karen L.; Yan, Renbin; Bizyaev, Dmitry; Boquien, Médéric; Brownstein, Joel R.; Bundy, Kevin; Drory, Niv; Heckman, Timothy M.; Law, David R.; Roman-Lopes, Alexandre; Pan, Kaike; Stanghellini, Letizia; Thomas, Daniel; Weijmans, Anne-Marie; Westfall, Kyle B.

    2016-05-01

    We study the spatially resolved excitation properties of the ionised gas in a sample of 646 galaxies using integral field spectroscopy data from SDSS-IV MaNGA. Making use of Baldwin-Philips-Terlevich diagnostic diagrams we demonstrate the ubiquitous presence of extended (kpc scale) low ionisation emission-line regions (LIERs) in both star forming and quiescent galaxies. In star forming galaxies LIER emission can be associated with diffuse ionised gas, most evident as extra-planar emission in edge-on systems. In addition, we identify two main classes of galaxies displaying LIER emission: `central LIER' (cLIER) galaxies, where central LIER emission is spatially extended, but accompanied by star formation at larger galactocentric distances, and `extended LIER' (eLIER) galaxies, where LIER emission is extended throughout the whole galaxy. In eLIER and cLIER galaxies, LIER emission is associated with radially flat, low Hα equivalent width of line emission (< 3 Å) and stellar population indices demonstrating the lack of young stellar populations, implying that line emission follows tightly the continuum due to the underlying old stellar population. The Hα surface brightness radial profiles are always shallower than 1/r2 and the line ratio [OIII]λ5007/[OII]λ3727,29 (a tracer of the ionisation parameter of the gas) shows a flat gradient. This combined evidence strongly supports the scenario in which LIER emission is not due to a central point source but to diffuse stellar sources, the most likely candidates being hot, evolved (post-asymptotic giant branch) stars. Shocks are observed to play a significant role in the ionisation of the gas only in rare merging and interacting systems.

  13. La Terre - les eaux - l'atmosphère.

    NASA Astrophysics Data System (ADS)

    Bec-Borsenberger, A.; Catoire, M.; Kovalevsky, J.; Guinot, B.; Cazenave, A.; Levallois, J. J.; Lecolazet, R.; Jobert, G.; Francheteau, J.; Le Mouël, J.-L.; Goguel, J.; Serpolay, R.; Berroir, A.; Mégie, G.; Crépon, M.; Saint-Guily, B.; Eyriès, M.-M.; Ramamonjiarisoa, A.; Buat-Menard, P.; Lalou, C.; Serra, L.; Lliboutry, L.; Lorius, C.

    Contents: Repères et forces de gravité (J. Kovalevsky). La rotation de la Terre (B. Guinot). La géodésie (J. Kovalevsky, A. Cazenave, J. J. Levallois). Les marées terrestres (R. Lecolazet). La sismologie (G. Jobert). Lithosphère et tectonique des plaques (J. Francheteau). Le champ magnétique terrestre (J.-L. Le Mouël). Modèles de la constitution physique de la Terre (G. Jobert). La géothermie (J. Goguel). Le rayonnement énergétique (R. Serpolay). Les fluides géophysiques (A. Berroir). L'atmosphère (A. Berroir, R. Serpolay). L'ozonosphère (G. Mégie). Les océans en mouvement (M. Crépon, B. Saint-Guily). La marée océanique (M.-M. Eyriès). La houle et les vagues (A. Ramamonjiarisoa). Les cycles géochimiques dans l'océan (P. Buat-Menard, C. Lalou). La circulation des eaux (L. Serra). Les glaces naturelles et leur dynamique (L. Lliboutry). L'évolution des climats, les données du passé (C. Lorius).

  14. Spectroscopie VUV sub-picoseconde : un détecteur haute cadence et un monochromateur pour impulsions femtosecondes

    NASA Astrophysics Data System (ADS)

    Martin, P.; Belsky, A.; Zinin, E.; Philippov, A.; Idir, M.; Moreno, T.; Darpentigny, G.; Salin, F.

    2003-06-01

    La très faible durée des impulsions harmoniques VUV est incompatible avec les systèmes dispersifs “classiques” existant comme les monochromateurs VUV utilisés actuellement, principalement auprès des sources de rayonnement synchrotron. Nous avons conçu un monochromateur VUV (domaine spectral: visible-30nm, 4-40eV) capable de fonctionner sans dispersion temporelle d'impulsions de quelques dizaines de fs. Son principe est basé sur l'utilisation de deux réseaux fonctionnant dans des ordres opposés en configuration optique de type Seya-Namioka, avec des optiques toriques pour la pré et post focalisation. Compte tenu des contraintes imposées le pouvoir de résolution attendu (environ 100) est suffisant pour des applications en spectroscopie VUV. Dans le cadre de cette thématique développée au CELIA et plus particulièrement en ce qui concerne l'aspect dynamique de la relaxation électronique, nous présentons ici également un détecteur de photons de grande sensibilité appelé “dissecteur” dont la résolution actuelle est d'environ 13ps mais qui sera prochainement portée à 1ps.

  15. Use of the comet assay to measure DNA damage in cells exposed to photosensitizers and gamma radiation

    NASA Astrophysics Data System (ADS)

    Pouget, J.-P.; Ravanat, J.-L.; Douki, T.; Richard, M.-J.; Cadet, J.

    1999-01-01

    We used the comet assay associated with DNA-glycosylases to estimate DNA damage in cells exposed to gamma irradiation or photosensitized either with methylene blue or orange acridine. A calibration performed using irradiation allowed the measurement of the steady-state level and the yield of 8-oxodGuo as well as strand breaks and alkali-labile sites. Nous avons utilisé la méthode des comètes associée à des ADN-glycosylases, pour estimer les dommages de l'ADN dans des cellules après l'exposition à un rayonnement gamma ou après photosensibilisation par le bleu de méthylène ou l'acridine orange. Une calibration de la méthode des comètes a permis de mesurer le niveau basal et les taux de formation de 8-oxodGuo ainsi que le nombre de cassures de brins et de sites alcali labiles.

  16. Microprobe analysis of teeth by synchrotron radiation: environmental contamination

    NASA Astrophysics Data System (ADS)

    Pinheiro, T.; Carvalho, M. L.; Casaca, C.; Barreiros, M. A.; Cunha, A. S.; Chevallier, P.

    1999-10-01

    An X-ray fluorescence set-up with microprobe capabilities, installed at the Laboratoire pour l'Utilisation du Rayonnement Électromagnétique (LURE) synchrotron (France) was used for elemental determination in teeth. To evaluate the influence of living habits in dental elemental composition nine teeth collected post-mortem were analysed, five from a miner and four from a fisherman. All teeth from the fisherman were healthy. From the miner some teeth were carious and one of them was filled with metallic amalgam. Teeth were sliced under the vertical plane and each slice was scanned from the root to the enamel for elemental profile determination. The synchrotron microprobe resolution was of 100 μm and incident photons of 18 keV energy were used. The elemental concentration values found suggest heterogeneity of the teeth material. Moreover, the distinct profiles for Mn, Sr, Br and Pb were found when teeth from the miner and from the fisherman are compared which can be associated with dietary habits and environmental influence. Higher concentrations of Mn and Sr were found for the fisherman teeth. In addition, Br was only observed in this group of teeth. Pb levels are higher for the miner teeth in particular for dentine regions. The influence of amalgam, such as, increase of Zn and Hg contents in the teeth material, is only noticed for the immediate surroundings of the treated cavity.

  17. The vacuum-ultraviolet photoelectron spectra of CH2F2 and CH2Cl2 revisited

    NASA Astrophysics Data System (ADS)

    Tuckett, Richard; Harvey, Jonelle; Hemberger, Patrick; Bodi, Andras

    2015-09-01

    The threshold photoelectron spectrum (TPES) of difluoromethane and dichloromethane has been recorded at the Swiss Light Source with a resolution of 2 meV or 16 cm-1. Electronic and vibronic transitions are simulated and assigned with the help of Franck-Condon (FC) calculations based on coupled cluster electronic structure calculations for the equilibrium geometries and harmonic vibrational frequencies of the neutrals, and of the ground and excited electronic states of the cations. Notwithstanding a high-resolution pulsed-field ionisation study on CH2F2 (Forysinski et al., 2010) in which a number of transitions to the X∼+ state have been recorded with unprecedented accuracy, we report the first complete vibrationally resolved overview of the low-lying electronic states of CH2X2+, X = F or Cl. Hydrogen atom loss from CH2F2+ occurs at low energy, making the ground state rather anharmonic and interpretation of the X∼+ band challenging in the harmonic approximation. By Franck-Condon fits, the adiabatic ionisation energies to the A∼+ 2B2, C∼+ 2A2 and D∼+ 2B2 states have been determined as 14.3 ± 0.1, 15.57 ± 0.01 and 18.0 ± 0.1 eV, respectively. The first band in the CH2Cl2 TPES is complex for a different reason, as it is the result of two overlapping ionic states, X∼+ 2B2 and A∼+ 2B1, with derived ionisation energies of 11.0 ± 0.2 and 11.317 ± 0.006 eV, and dominated by an extended progression in the CCl2 bend (in X∼+) and a short progression in the CCl2 symmetric stretch (in A∼+), respectively. Furthermore, even though Koopmans' approximation holds for the vertical ionisations, the X∼+ state of CH2Cl2+ is stabilized by geometry relaxation and corresponds to ionisation from the (HOMO-1) orbital. That is, the first two vertical ionisation energies are in the same order as the negative of the orbital energies of the highest occupied orbitals, but the adiabatic ionisation energy corresponding to electron removal from the (HOMO-1) is lower than the

  18. Extended warm gas in the ULIRG Mrk273: Galactic outflows and tidal debris

    NASA Astrophysics Data System (ADS)

    Rodríguez Zaurín, J.; Tadhunter, C. N.; Rupke, D. S. N.; Veilleux, S.; Spoon, H. W. W.; Chiaberge, M.; Ramos Almeida, C.; Batcheldor, D.; Sparks, W. B.

    2014-11-01

    We present new HST/ACS medium- and narrow-band images and optical Isaac Newton Telescope long-slit spectra of the merging system Mrk273. The HST observations sample the [OIII]λλ4959,5007 emission from the galaxy and the nearby continuum. These data were taken as a part of a larger study of ultraluminous infrared galaxies (ULIRGs) with the aim of investigating the importance of the warm, AGN induced outflows in such objects. The HST images show that the morphologies of the extended continuum and the ionised gas emission from the galaxy are decoupled, extending almost perpendicular to each other. In particular, we detect for the first time a spectacular structure of ionised gas in the form of filaments and clumps that extend ~23 kpc to the east of the nuclear region. The quiescent ionised gas kinematics at these locations suggests that these filaments are tidal debris left over from a secondary merger event that are illuminated by an AGN in the nuclear regions. The images also reveal a complex morphology in the nuclear region of the galaxy for both the continuum and the [OIII] emission. Consistent with this complexity, we find a wide diversity of emission line profiles in these regions. Kinematic disturbance in the form of broad (FWHM> 500 km s-1) and/or strongly shifted (| ΔV | > 150 km s-1 ) emission line components is found at almost all locations in the nuclear regions, but confined to a radius of ~4 kpc to the east and west of the northern nucleus. In most cases, we are able to fit the profiles of all the emission lines of different ionisation with a kinematic model using two or three Gaussian components. From these fits, we derive diagnostic line ratios that are used to investigate the ionisation mechanisms at the different locations in the galaxy. We show that these line ratios are generally consistent with photoionisation by an AGN as the main ionisation mechanism. Finally, the highest surface brightness [OIII] emission is found in a compact region that is

  19. The distribution of equivalent widths in long GRB afterglow spectra

    NASA Astrophysics Data System (ADS)

    de Ugarte Postigo, A.; Fynbo, J. P. U.; Thöne, C. C.; Christensen, L.; Gorosabel, J.; Milvang-Jensen, B.; Schulze, S.; Jakobsson, P.; Wiersema, K.; Sánchez-Ramírez, R.; Leloudas, G.; Zafar, T.; Malesani, D.; Hjorth, J.

    2012-12-01

    Context. The extreme brightness of gamma-ray burst (GRB) afterglows and their simple spectral shape make them ideal beacons to study the interstellar medium of their host galaxies through absorption line spectroscopy at almost any redshift. Aims: We describe the distribution of rest-frame equivalent widths (EWs) of the most prominent absorption features in GRB afterglow spectra, providing the means to compare individual spectra to the sample and identify its peculiarities. Methods: Using 69 low-resolution GRB afterglow spectra, we conduct a study of the rest-frame EWs distribution of features with an average rest-frame EW larger than 0.5 Å. To compare an individual GRB with the sample, we develop EW diagrams as a graphical tool, and we give a catalogue with diagrams for the 69 spectra. We introduce a line strength parameter (LSP) that allows us to quantify the strength of the absorption features in a GRB spectrum as compared to the sample by a single number. Using the distributions of EWs of single-species features, we derive the distribution of their column densities by a curve of growth (CoG) fit. Results: We find correlations between the LSP and the extinction of the GRB, the UV brightness of the host galaxies and the neutral hydrogen column density. However, we see no significant evolution of the LSP with the redshift. There is a weak correlation between the ionisation of the absorbers and the energy of the GRB, indicating that, either the GRB event is responsible for part of the ionisation, or that galaxies with high-ionisation media produce more energetic GRBs. Spectral features in GRB spectra are, on average, 2.5 times stronger than those seen in QSO intervening damped Lyman-α (DLA) systems and slightly more ionised. In particular we find a larger excess in the EW of C ivλλ1549 relative to QSO DLAs, which could be related to an excess of Wolf-Rayet stars in the environments of GRBs. From the CoG fitting we obtain an average number of components in the

  20. Analyse numérique du problème de déplacement du noyau fondu en soudage par points de tôles à différentes épaisseurs

    NASA Astrophysics Data System (ADS)

    Benkedda, Y.; Tahar Chaouch, K.; Ibrir, B.

    2005-05-01

    Le soudage par résistance par points est une technique d'assemblage très répandue, en particulier dans l'industrie automobile, parce qu'elle est rapide, fiable et bon marché. Pour cela, la réalisation d'un point de soudure de qualité reste encore une préoccupation de l'industrie, surtout lorsqu'il s'agit de souder des tôles à différentes épaisseurs. Les premiers modèles mathématiques et expérimentaux qui couvrent ces différents aspects, sont principalement dirigés vers les modèles de transfert de chaleur ou vers les phénomènes de surfaces (modèles de surfaces) ; ces derniers, sont un problème d'importance, puisqu'ils interviennent chaque fois qu'un transfert de chaleur s'effectue entre deux solides accolés. Les physiciens ont étudie expérimentalement la réponse de la région de contact de deux solides aux pulsations de courant. Ils ont montré que le contact possède une résistance de resserrement due aux aspérités de surface, et que la température moyenne à l'interface des deux solides sous un chargement uniforme produit un adoucissement local lequel fait augmenter la région de contact. Le but de ce travail est consacré à l'analyse de l'influence des épaisseurs de tôles sur la position du noyau fondu. Expérimentalement, il a été montré que lorsque le rapport des épaisseurs est compris entre 1/1 et 1/10, le noyau fondu se déplace vers la pièce la plus épaisse. Ce phénomène peut s'expliquer à partir d'une étude thermique. Nous proposons donc, de résoudre le problème de transfert thermique transitoire associé au processus de soudage par points moyennant une méthode numérique. Ce modèle est capable de prédire l'évolution du noyau fondu en fonction des paramètres du procédé à savoir l'intensité de soudage et temps de soudage, ainsi que la répartition thermique en chaque point de l'assemblage.

  1. Electron irradiation of YBa2CU3O7 ceramics

    NASA Astrophysics Data System (ADS)

    Konczykowski, Marcin; Gilchrist, John

    1991-11-01

    Irradiation treatments generally have three effects on the superconducting properties of high T_c ceramics. The superconductivity of the grains is modified, as witnessed by a shift in T_c. The mixed-state properties of the grains are changed due to the additional pinning centres, and inter-granular links are modified by the accumulation of irradiation defects at the grain boundaries. These effects are discussed with particular reference to the irradiation of polycrystalline YBa2CU3O7 at low temperature with 2-3 MeV electrons, which initially produces a random distribution of Frenkel defects. We draw attention to several kinds of measurements which can be made in situ or after transferring the sample to a measuring cryostat : the transfer allows the defects to recombine or migrate. Various DC and AC measurement methods are compared, and the three effects of irradiation are demonstrated. The irreversibility line is found to shift with T_c. Les propriétés supraconductrices des céramiques à haut T_c, sont généralement influencées dans trois domaines distincts par les irradiations. D'une part la supraconductivité des grains est modifiée, comme en témoigne le changement de T_c. D'autre part les propriétés à l'état mixte des grains sont modifiées par la présence de nouveaux centres de piégeage. Enfin les liaisons inter-granulaires sont altérées par l'accumulation de défauts d'irradiation aux joints de grains. Nous insistons particulièrement sur l'irradiation de YBa2CU3O7 polycristallin à basse température avec des électrons de 2 à 3 MeV, ce qui produit, en premier lieu, des défauts de Frenkel à répartition aléatoire. Plusieurs types de mesures peuvent être faites soit in situ, soit après transfert de l'échantillon dans un cryostat de mesures: le transfert permet la recombinaison ou la migration des défauts. Différentes méthodes en courant continu et en alternatif sont comparées, et les effets de l'irradiation sur les trois domaines ci

  2. Propriétés électriques des oxydes de tantale électrogénérés en milieu aqueux

    NASA Astrophysics Data System (ADS)

    Nâamoune, F.; Hammouche, A.; Kahoul, A.

    1998-07-01

    The tantalum anodization in aqueous solutions has been investigated by chronopotentiometry. Analysis of admittance diagrams allows the caracterization of the electrical properties of the formed oxide layer. The electrode/electrolyte interface can bemodelized by an equivalent circuit consisting of a resistance Rp in parallel with a capacitance Cp, this loop being inseries with a resistance Rs. The results have shown that the electrical properties of the formed oxide layer depend on the nature of the electrolyte. For a given electrolyte, the Rp.Cp product is constant for a wide range of oxide thickness. Its value is used as a criterion of the oxide quality; high values of this product indicate that the electronic transfert through the oxide layer is difficult, corresponding to highly passivated electrodes. L'anodisation du tantale en milieu aqueux a été réalisée par chronopotentiométrie. L'exploitation des diagrammes d'admittance permet d'accéder aux propriétés électriques de la couche d'oxyde formée. L'interface électrode/électrolyte peut être modélisée par un circuit équivalent comportant une résistance Rp en parallèle avec une capacité Cp. Cette boucle étant elle-même en série avec une résistance Rs. Les résultats ont montré l'influence du choix de l'électrolyte sur les propriétés électriques des couches d'oxyde formées. Dans un milieu donné, le produit Rp.Cp est constant pour une large gamme d'épaisseurs. La valeur de ce produit constitue un critère de qualité des couches formées ; une valeur élevée indique que le transfert électronique à travers la couche d'oxyde est difficile, donc un caratère plus marqué.

  3. The KMOS AGN Survey at High Redshift (KASHz)

    NASA Astrophysics Data System (ADS)

    Harrison, C.; Alexander, D.; Mullaney, J.; Stott, J.; Swinbank, M.; Arumugam, V.; Bauer, F.; Bower, R.; Bunker, A.; Sharples, R.

    2016-03-01

    The KMOS AGN Survey at High Redshift (KASHz) is an extensive observational programme to obtain spatially resolved spectroscopy of distant galaxies that host rapidly growing supermassive black holes (i.e., active galactic nuclei [AGN]). By exploiting the unique capabilities of KMOS we will spatially resolve the ionised gas kinematics in around 200 such galaxies. A fundamental prediction of galaxy formation models is that AGN inject considerable energy into their host galaxies and ultimately destroy or remove star-forming material via outflows. However, until now, observational constraints of this prediction have been limited to only a small number of distant galaxies. KASHz will provide the strongest constraints to date on the prevalence, properties and impact of ionised outflows in the host galaxies of distant AGN. The survey is described and our first results presented.

  4. Protection from radon exposure at home and at work in the directive 2013/59/Euratom.

    PubMed

    Bochicchio, F

    2014-07-01

    In recent years, international organisations involved in radiation protection and public health have produced new guidance, recommendations and requirements aiming better protection from radon exposure. These organisations have often worked in close collaboration in order to facilitate the establishment of harmonised standards. This paper deals with such standards and specifically with the new European Council Directive of 5 December 2013 on basic safety standards for protection against the dangers arising from exposure to ionising radiation (2013/59/Euratom). This new Directive has established a harmonised framework for the protection against ionising radiations, including protection from radon exposure. Requirements for radon in workplace are much more tightening than in previous Directive, and exposures to radon in dwellings are regulated for the first time in a Directive. Radon-related articles of this Directive are presented and discussed in this paper, along with some comparisons with other relevant international standards. PMID:24729590

  5. Liquid chromatographic tandem mass spectrometric determination of five coccidiostats in poultry eggs and feed.

    PubMed

    Mortier, Leen; Daeseleire, Els; Van Peteghem, Carlos

    2005-06-25

    A method is described which permits the quantitative detection of the chemical coccidiostats halofuginone, robenidine, diclazuril, nicarbazin and dimetridazole and its main metabolite 2-hydroxydimetridazole in poultry eggs and feed. Sample preparations were kept very simple and are based upon extraction with an organic solvent. Sample extracts were injected into the liquid chromatography tandem mass spectrometry (LC-MS/MS) system on a C18 column and a gradient elution was performed. Dimetridazole-D3 and diclazuril-bis, a structural analogue of diclazuril, were used as internal standards. Detection was performed on a triple quadrupole mass spectrometer in the selected reaction monitoring mode after ionisation in the positive or negative electrospray ionisation mode. Argon was applied as collision gas for collision induced dissociation. Validation of the methods was performed based on Commission Decision 2002/657/EC [Official Journal of the European Communities L221 (2002) 8]. PMID:15893963

  6. Synthesis and identification of hydroxylated metabolites of the anti-estrogenic agent cyclofenil.

    PubMed

    Gärtner, Peter; Hofbauer, Karin; Reichel, Christian; Geisendorfer, Thomas; Gmeiner, Günter

    2008-07-01

    The detection of metabolites of the anti-estrogenic substance cyclofenil, listed on the World Anti-Doping Agency (WADA) Prohibited List since 2004 is described. Target substances are hydroxylated metabolites, bearing an aliphatic hydroxyl group either in the 2-, 3- or 4-position of the aliphatic ring, in addition to the phenolic functions on the aromatic rings. Structural identification used NMR as well as high-resolution mass spectrometry after nano-electrospray ionisation (ESI). Unambiguous detection of all three synthesised cyclofenil metabolites M1-M3 was done using gas chromatography for separation and electron ionisation mass spectrometry for detection of the per-silylated compounds in comparison with a reference urine deriving from an excretion study within the WADA 2007 Educational Programme. PMID:18576435

  7. Analysis of dose-LET distribution in the human body irradiated by high energy hadrons.

    PubMed

    Sato, T; Tsuda, S; Sakamoto, Y; Yamaguchi, Y; Niita, K

    2003-01-01

    For the purposes of radiological protection, it is important to analyse profiles of the particle field inside a human body irradiated by high energy hadrons, since they can produce a variety of secondary particles which play an important role in the energy deposition process, and characterise their radiation qualities. Therefore Monte Carlo calculations were performed to evaluate dose distributions in terms of the linear energy transfer of ionising particles (dose-LET distribution) using a newly developed particle transport code (Particle and Heavy Ion Transport code System, PHITS) for incidences of neutrons, protons and pions with energies from 100 MeV to 200 GeV. Based on these calculations, it was found that more than 80% and 90% of the total deposition energies are attributed to ionisation by particles with LET below 10 keV microm(-1) for the irradiations of neutrons and the charged particles, respectively. PMID:14653335

  8. Cooking strongly coupled plasmas

    NASA Astrophysics Data System (ADS)

    Clérouin, Jean

    2015-09-01

    We present the orbital-free method for dense plasmas which allows for efficient variable ionisation molecular dynamics. This approach is a literal application of density functional theory where the use of orbitals is bypassed by a semi-classical estimation of the electron kinetic energy through the Thomas-Fermi theory. Thanks to a coherent definition of ionisation, we evidence a particular regime in which the static structure no longer depends on the temperature: the Γ-plateau. With the help of the well-known Thomas-Fermi scaling laws, we derive the conditions required to obtain a plasma at a given value of the coupling parameter and deduce useful fits. Static and dynamical properties are predicted as well as a a simple equation of state valid on the Γ-plateau. We show that the one component plasma model can be helpful to describe the correlations in real systems.

  9. The enhancing of a cysteine proteinase activity at acidic pH by protein engineering, the role of glutamic 50 in the enzyme mechanism of caricain.

    PubMed

    Ikeuchi, Y; Katerelos, N A; Goodenough, P W

    1998-10-16

    Carica papaya produces four cysteine proteinases. Calculations show that the Cys25, His159 essential ion pair is fully ionised at pH 2.99, where activity cannot be detected, but apparently an additional ionisation with a pKa of 4 is essential for activity (an electrostatic switch). Caricain (EC 3.4.22.30) wt and D158E genetic backgrounds were used to study the contribution of E50A to activity. E50 or E135 are candidates for the switch, E50A would be expected to reduce activity. However, activity increased at pH 5.0 in both backgrounds and at the pH optimum in D158E E50A but decreased slightly in the wt background. This challenges the hypothesis of an electrostatic switch. PMID:9804178

  10. A Large-Scale, Low-Frequency Murchison Widefield Array Survey of Galactic H ii Regions between 260 < l < 340

    NASA Astrophysics Data System (ADS)

    Hindson, L.; Johnston-Hollitt, M.; Hurley-Walker, N.; Callingham, J. R.; Su, H.; Morgan, J.; Bell, M.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Deshpande, A. A.; Dwarakanath, K. S.; For, B.-Q.; Gaensler, B. M.; Greenhill, L. J.; Hancock, P.; Hazelton, B. J.; Kapińska, A. D.; Kaplan, D. L.; Lenc, E.; Lonsdale, C. J.; Mckinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Oberoi, D.; Offringa, A.; Ord, S. M.; Procopio, P.; Prabu, T.; Shankar, N. Udaya; Srivani, K. S.; Staveley-Smith, L.; Subrahmanyan, R.; Tingay, S. J.; Wayth, R. B.; Webster, R. L.; Williams, A.; Williams, C. L.; Wu, C.; Zheng, Q.

    2016-05-01

    We have compiled a catalogue of H ii regions detected with the Murchison Widefield Array between 72 and 231 MHz. The multiple frequency bands provided by the Murchison Widefield Array allow us identify the characteristic spectrum generated by the thermal Bremsstrahlung process in H ii regions. We detect 306 H ii regions between 260° < l < 340° and report on the positions, sizes, peak, integrated flux density, and spectral indices of these H ii regions. By identifying the point at which H ii regions transition from the optically thin to thick regime, we derive the physical properties including the electron density, ionised gas mass, and ionising photon flux, towards 61 H ii regions. This catalogue of H ii regions represents the most extensive and uniform low frequency survey of H ii regions in the Galaxy to date.

  11. A review of the results from the German Wismut uranium miners cohort.

    PubMed

    Walsh, L; Grosche, B; Schnelzer, M; Tschense, A; Sogl, M; Kreuzer, M

    2015-04-01

    The Wismut cohort is currently the largest single study on the health risks associated with occupational exposures to ionising radiation and dust accrued during activities related to uranium mining. The cohort has ∼59 000 male workers, first employed between 1946 and 1989, at the Wismut Company in Germany. The main effect is a statistically significant increase in mortality from lung cancer with both increasing cumulative radon exposure and silica dust exposure. Risks for cancers of the extrathoracic airways, all extra-pulmonary cancers and cardiovascular diseases associated with radiation exposures have been evaluated. Cohort mortality rates for some other cancer sites, stomach and liver, are statistically significantly increased in relation to the general population, but not statistically significantly related to occupational exposures. No associations between leukaemia mortality and occupational doses of ionising radiation were found. PMID:25267854

  12. Identification of the isomers using principal component analysis (PCA) method

    NASA Astrophysics Data System (ADS)

    Kepceoǧlu, Abdullah; Gündoǧdu, Yasemin; Ledingham, Kenneth William David; Kilic, Hamdi Sukur

    2016-03-01

    In this work, we have carried out a detailed statistical analysis for experimental data of mass spectra from xylene isomers. Principle Component Analysis (PCA) was used to identify the isomers which cannot be distinguished using conventional statistical methods for interpretation of their mass spectra. Experiments have been carried out using a linear TOF-MS coupled to a femtosecond laser system as an energy source for the ionisation processes. We have performed experiments and collected data which has been analysed and interpreted using PCA as a multivariate analysis of these spectra. This demonstrates the strength of the method to get an insight for distinguishing the isomers which cannot be identified using conventional mass analysis obtained through dissociative ionisation processes on these molecules. The PCA results dependending on the laser pulse energy and the background pressure in the spectrometers have been presented in this work.

  13. Imaging Mass Spectrometric Analysis of Neurotransmitters: A Review

    PubMed Central

    Romero-Perez, Gustavo A.; Takei, Shiro; Yao, Ikuko

    2014-01-01

    Imaging mass spectrometry (IMS) is a toolbox of versatile techniques that enable us to investigate analytes in samples at molecular level. In recent years, IMS, and especially matrix-assisted laser desorption/ionisation (MALDI), has been used to visualise a wide range of metabolites in biological samples. Simultaneous visualisation of the spatial distribution of metabolites in a single sample with little tissue disruption can be considered as one important advantage of MALDI over other techniques. However, several technical hurdles including low concentrations and rapid degradation rates of small molecule metabolites, matrix interference of signals and poor ionisation, need to be addressed before MALDI can be considered as a reliable tool for the analysis of metabolites such as neurotransmitters in brain tissues from different sources including humans. In the present review we will briefly describe current MALDI IMS techniques used to study neurotransmitters and discuss their current status, challenges, as well as future prospects. PMID:26819893

  14. Plasma formation on a metal surface under combined action of laser and microwave radiation

    SciTech Connect

    Gavrilyuk, A P; Shaparev, N Ya

    2013-10-31

    By means of numerical modelling of the combined effect of laser (1.06 mm) and microwave (10{sup 10} – 10{sup 13} s{sup -1}) radiation on the aluminium surface in vacuum it is shown that the additional action of microwave radiation with the frequency 10{sup 12} s{sup -1} provides complete ionisation of the metal vapour (for the values of laser radiation duration and intensity used in the calculations), while in the absence of microwave radiation the vapour remains weakly ionised. The mathematical model used accounts for the processes, occurring in the condensed phase (heat conduction, melting), the evaporation and the kinetic processes in the resulting vapour. (interaction of laser radiation with matter. laser plasma)

  15. The scattering of muons in low- Z materials

    NASA Astrophysics Data System (ADS)

    Attwood, D.; Bell, P.; Bull, S.; McMahon, T.; Wilson, J.; Fernow, R.; Gruber, P.; Jamdagni, A.; Long, K.; McKigney, E.; Savage, P.; Curtis-Rouse, M.; Edgecock, T. R.; Ellis, M.; Lidbury, J.; Murray, W.; Norton, P.; Peach, K.; Ishida, K.; Matsuda, Y.; Nagamine, K.; Nakamura, S.; Marshall, G. M.; Benveniste, S.; Cline, D.; Fukui, Y.; Lee, K.; Pischalnikov, Y.; Holmes, S.; Bogacz, A.

    2006-09-01

    This paper presents the measurement of the scattering of 172 MeV/c muons in assorted materials, including liquid hydrogen, motivated by the need to understand ionisation cooling for muon acceleration. Data are compared with predictions from the GEANT4 simulation code and this simulation is used to deconvolute detector effects. The scattering distributions obtained are compared with the Moliere theory of multiple scattering and, in the case of liquid hydrogen, with ELMS. With the exception of ELMS, none of the models are found to provide a good description of the data. The results suggest that ionisation cooling will work better than would be predicted by GEANT 4.7.0p01.

  16. Phase control of two-color filamentation

    NASA Astrophysics Data System (ADS)

    Doussot, J.; Béjot, P.; Karras, G.; Billard, F.; Faucher, O.

    2015-09-01

    An original way to control the nonlinear propagation of an intense pulse is presented. The co-propagation of a weak (≃ 1%) third-harmonic pulse with an intense laser pulse experiencing filamentation allows control of the nonlinear propagation of the latter. Because of quantum interference during the two-color ionisation process, the latter can be significantly enhanced or suppressed by a simple tuning of the relative phase between the two fields. As a first application, we demonstrate the production and control of an axially modulated plasma channel. Finally, an analytical formula describing the two-color ionisation rate as a function of the relative phase and intensity of the two fields is presented and tested in a propagation code. The numerical results successfully reproduce the experimental ones.

  17. The FLASHForward facility at DESY

    NASA Astrophysics Data System (ADS)

    Aschikhin, A.; Behrens, C.; Bohlen, S.; Dale, J.; Delbos, N.; di Lucchio, L.; Elsen, E.; Erbe, J.-H.; Felber, M.; Foster, B.; Goldberg, L.; Grebenyuk, J.; Gruse, J.-N.; Hidding, B.; Hu, Zhanghu; Karstensen, S.; Knetsch, A.; Kononenko, O.; Libov, V.; Ludwig, K.; Maier, A. R.; Martinez de la Ossa, A.; Mehrling, T.; Palmer, C. A. J.; Pannek, F.; Schaper, L.; Schlarb, H.; Schmidt, B.; Schreiber, S.; Schwinkendorf, J.-P.; Steel, H.; Streeter, M.; Tauscher, G.; Wacker, V.; Weichert, S.; Wunderlich, S.; Zemella, J.; Osterhoff, J.

    2016-01-01

    The FLASHForward project at DESY is a pioneering plasma-wakefield acceleration experiment that aims to produce, in a few centimetres of ionised hydrogen, beams with energy of order GeV that are of quality sufficient to be used in a free-electron laser. The plasma is created by ionising a gas in a gas cell with a multi-TW laser system. The plasma wave will be driven by high-current-density electron beams from the FLASH linear accelerator. The laser system can also be used to provide optical diagnostics of the plasma and electron beams due to the <30 fs synchronisation between the laser and the driving electron beam. The project will explore both external and internal witness-beam injection techniques. The operation parameters of the experiment are discussed, as well as the scientific programme.

  18. Vibrational spectroscopy of size-assigned p-cresol/H 2O-clusters in the S 0 and S 1 state

    NASA Astrophysics Data System (ADS)

    Pohl, M.; Schmitt, M.; Kleinermanns, K.

    1991-02-01

    Vibrational spectra of supersonically cooled complexes of p-cresol with H 2O and CH 3OH were analysed by mass-resolved two-photon ionisation, dispersed fluorescence and stimulated emission, detected by two-colour ionisation dip. In p-cresol·(H 2O) 1 progressions of the intermolecular cluster stretch vibration and its combination bands with intramolecular cluster vibrations were observed with similar frequencies in the S 0 and S 1 state. In p-cresol·(H 2O) 3 and p-cresol·(CH 3OH) 1, further intense intermolecular bands arise, namely the hydrogen-bridge bending and torsion vibration. This can be attributed to the lower symmetry of these clusters. Ab initio quantum chemical calculations show p-cresol·(H 2O) 3 to have a higher H-bond stretch frequency than p-cresol·(H 2O) 1 because its (unsymmetric) cyclic structure is more rigid.

  19. Partial purification and characterisation of the peptide precursors of the cocoa-specific aroma components.

    PubMed

    Voigt, Jürgen; Janek, Katharina; Textoris-Taube, Kathrin; Niewienda, Agathe; Wöstemeyer, Johannes

    2016-02-01

    Essential precursors of the cocoa-specific aroma notes are formed during fermentation of the cocoa beans by acid-induced proteolysis. It has been shown that, in addition to free amino acids, hydrophilic peptides derived from the vicilin-class(7S) globular storage protein are required for the generation of the cocoa-specific aroma notes during the roasting process. To identify those peptides responsible for the generation of the cocoa-specific aroma components, we have developed a procedure for the fractionation of the aroma precursor extract from well-fermented cocoa beans by ligand-exchange and subsequent Sephadex-LH20 chromatography. The cocoa-specific aroma precursor fractions were characterised by matrix-assisted laser-desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF) and the determination of their amino acid sequences by electrospray ionisation mass spectrometry (ESI-MS/MS). PMID:26304401

  20. An evaluation of radiation damage to solid state components flown in low earth orbit satellites.

    PubMed

    Shin, Myung-Won; Kim, Myung-Hyun

    2004-01-01

    The effects of total ionising radiation dose upon commercial off-the-shelf semiconductors fitted to satellites operating in low Earth orbit (LEO) conditions was evaluated. The evaluation was performed for the Korea Institute of Technology SATellite-1, (KITSAT-1) which was equipped with commercial solid state components. Two approximate calculation models for space radiation shielding were developed. Verification was performed by comparing the results with detailed three-dimensional calculations using the Monte-Carlo method and measured data from KITSAT-1. It was confirmed that the developed approximate models were reliable for satellite shielding calculations. It was also found that commercial semiconductor devices, which were not radiation hardened, could be damaged within their lifetime due to the total ionising dose they are subject to in the LEO environment. To conclude, an intensive shielding analysis should be considered when commercial devices are used. PMID:15103058

  1. Automated analysis of XANES: A feasibility study of Au reference compounds

    NASA Astrophysics Data System (ADS)

    Chang, S.-Y.; Molleta, L. B.; Booth, S. G.; Uehara, A.; Mosselmans, J. F. W.; Ignatyev, K.; Dryfe, R. A. W.; Schroeder, S. L. M.

    2016-05-01

    With the advent of high-throughput and imaging core level spectroscopies (including X-ray absorption spectroscopy, XAS, as well as electron energy loss spectroscopy, EELS), automated data processing, visualisation and analytics will become a necessity. As a first step towards these objectives we examined the possibilities and limitations of a simple automated XANES peak fitting procedure written in MATLAB, for the parametrisation of XANES features, including ionisation potentials as well as the energies and intensities of electronic transitions. Using a series of Au L3-edge XANES reference spectra we show that most of the relevant information can be captured through a small number of rules applied to constrain the fits. Uncertainty in this strategy arises mostly when the ionisation potential (IP) overlaps with weak electronic transitions or features in the continuum beyond the IP, which can result in ambiguity through multiple equally good fits.

  2. Prototype of a high-power, high-energy industrial XeCl laser

    NASA Astrophysics Data System (ADS)

    Borisov, V. M.; Demin, A. I.; Khristoforov, O. B.

    2015-03-01

    We discuss the results of fabrication and experimental study of a high-power excimer XeCl laser for industrial applications. Compactness of the laser is achieved by the employment of a laser chamber based on a ceramic tube made of Al2O3. High laser output energy (1.5 - 2.5 J pulse-1) is obtained using a wide-aperture (up to 55 × 30 mm) volume discharge with pre-ionisation by a creeping discharge. The pre-ionisation is realised through a semitransparent electrode by the UV radiation of a creeping discharge in the form of uniform plasma sheet on a surface of a plane sapphire plate. The operating lifetime of the gas mixture amounts to ~57 × 106 pulses at a stabilised average laser power of 450 W. The results obtained demonstrate real prospects for developing a new class of excimer XeCl lasers with an average power of ~1 kW.

  3. Radiochromic 3D Detectors

    NASA Astrophysics Data System (ADS)

    Oldham, Mark

    2015-01-01

    Radiochromic materials exhibit a colour change when exposed to ionising radiation. Radiochromic film has been used for clinical dosimetry for many years and increasingly so recently, as films of higher sensitivities have become available. The two principle advantages of radiochromic dosimetry include greater tissue equivalence (radiologically) and the lack of requirement for development of the colour change. In a radiochromic material, the colour change arises direct from ionising interactions affecting dye molecules, without requiring any latent chemical, optical or thermal development, with important implications for increased accuracy and convenience. It is only relatively recently however, that 3D radiochromic dosimetry has become possible. In this article we review recent developments and the current state-of-the-art of 3D radiochromic dosimetry, and the potential for a more comprehensive solution for the verification of complex radiation therapy treatments, and 3D dose measurement in general.

  4. The interaction of excited atoms and few-cycle laser pulses

    NASA Astrophysics Data System (ADS)

    Calvert, James; Xu, Han; Palmer, Adam; Laban, Dane; Litvinyuk, Igor; Kielpinksi, David; Sang, Robert; Glover, Rohan; Tong, Xiao-Min; Dolmatov, Valeriy; Kheifets, Anatoli; Bartschat, Klaus

    2016-05-01

    We present the observations of the ionisation of neon in a metastable atomic state utilising a strong-field fewcycle laser pulse. We compare the observations to theoretical predictions based on the Ammosov-Delone-Krainov (ADK) theory and a solution to the time-dependent Schrödinger equation (TDSE). The TDSE provides better agreement with the experimental data than the ADK theory. We optically pump the target atomic species and demonstrate that the ionisation rate depends on the spin state of the target atoms and provide physically transparent interpretation of such a spin dependence in the frameworks of the spin-polarised Hartree-Fock and random-phase approximations. ARC DP120101805, DP 110101894, NSF PHY-1305085, PHY-1430245.

  5. Testing accretion disk instabilities in X-ray binaries

    NASA Astrophysics Data System (ADS)

    Bagińska, Patrycja; Różańska, Agata; Janiuk, Agnieszka; Czerny, Bożena

    2014-12-01

    We study disk instabilities in black hole binaries in which X-ray novae outbursts were observed. Typically, one outburst occurs in each light curve, with total duration from 30 up to 400 days. The shape of an outburst can be very regular fast rise exponential decay (FRED) characteristic for ionisation instability mechanism that occurs in accretion disks, or irregular suggesting that, beside FRED, additional flickering occurs. We use the model which predicts time dependent evolution of ionisation instability in an accretion disk around black hole, assuming viscosity parameter to be proportional to the total pressure. We test it in detail for two objects: GX 339-4 and XTE J1818-245. The modelled light curves agree with the collected RXTE light curves, indicating that disk instability works in those objects.

  6. Ionization with low-frequency fields in the tunneling regime

    PubMed Central

    Dura, J.; Camus, N.; Thai, A.; Britz, A.; Hemmer, M.; Baudisch, M.; Senftleben, A.; Schröter, C. D.; Ullrich, J.; Moshammer, R.; Biegert, J.

    2013-01-01

    Strong-field ionisation surprises with richness beyond current understanding despite decade long investigations. Ionisation with mid-IR light has promptly revealed unexpected kinetic energy structures that seem related to unanticipated quantum trajectories of the electrons. We measure first 3D momentum distributions in the deep tunneling regime (γ = 0.3) and observe surprising new electron dynamics of near-zero momentum electrons and extremely low momentum structures, below the eV, despite very high quiver energies of 95 eV. Such level of high-precision measurements at only 1 meV above the threshold, despite 5 orders higher ponderomotive energies, has now become possible with a specifically developed ultrafast mid-IR light source in combination with a reaction microscope, thereby permitting a new level of investigations into mid-IR recollision physics. PMID:24043222

  7. Microwave breakdown for the TE{sub 10} mode in a rectangular waveguide

    SciTech Connect

    Malik, Hitendra K.; Aria, Anil K.

    2013-08-15

    Microwave breakdown is studied for the lowest order TE{sub 10} mode in a rectangular waveguide with the help of direct variational approach via the continuity equation along with the use of ionisation and attachment frequency. We investigate the role of the ionisation, attachment of electron with neutral gas or air molecules and the diffusion on microwave breakdown threshold in the waveguide filled with air or Ar Gas. We examine the effect of different gases and microwave parameters on the diffusion length and the breakdown threshold of electric field of continuous microwave and pulsed microwave. We also employ numerical approach for obtaining the results and compare them with the ones of variational approach.

  8. Protostars: Forges of cosmic rays?

    NASA Astrophysics Data System (ADS)

    Padovani, M.; Marcowith, A.; Hennebelle, P.; Ferrière, K.

    2016-05-01

    Context. Galactic cosmic rays are particles presumably accelerated in supernova remnant shocks that propagate in the interstellar medium up to the densest parts of molecular clouds, losing energy and their ionisation efficiency because of the presence of magnetic fields and collisions with molecular hydrogen. Recent observations hint at high levels of ionisation and at the presence of synchrotron emission in protostellar systems, which leads to an apparent contradiction. Aims: We want to explain the origin of these cosmic rays accelerated within young protostars as suggested by observations. Methods: Our modelling consists of a set of conditions that has to be satisfied in order to have an efficient cosmic-ray acceleration through diffusive shock acceleration. We analyse three main acceleration sites (shocks in accretion flows, along the jets, and on protostellar surfaces), then we follow the propagation of these particles through the protostellar system up to the hot spot region. Results: We find that jet shocks can be strong accelerators of cosmic-ray protons, which can be boosted up to relativistic energies. Other promising acceleration sites are protostellar surfaces, where shocks caused by impacting material during the collapse phase are strong enough to accelerate cosmic-ray protons. In contrast, accretion flow shocks are too weak to efficiently accelerate cosmic rays. Though cosmic-ray electrons are weakly accelerated, they can gain a strong boost to relativistic energies through re-acceleration in successive shocks. Conclusions: We suggest a mechanism able to accelerate both cosmic-ray protons and electrons through the diffusive shock acceleration mechanism, which can be used to explain the high ionisation rate and the synchrotron emission observed towards protostellar sources. The existence of an internal source of energetic particles can have a strong and unforeseen impact on the ionisation of the protostellar disc, on the star and planet formation

  9. Further considerations of cosmic ray modulation of infra-red radiation in the atmosphere

    NASA Astrophysics Data System (ADS)

    Aplin, K. L.; Lockwood, M.

    2015-08-01

    Understanding effects of ionisation in the lower atmosphere is a new interdisciplinary area, crossing the traditionally distinct scientific boundaries between astro-particle and atmospheric physics and also requiring understanding of both heliospheric and magnetospheric influences on cosmic rays. Following the paper of Erlykin et al. (2014) we develop further the interpretation of our observed changes in long-wave (LW) radiation, Aplin and Lockwood (2013) by taking account of both cosmic ray ionisation yields and atmospheric radiative transfer. To demonstrate this, we show that the thermal structure of the whole atmosphere needs to be considered along with the vertical profile of ionisation. Allowing for, in particular, ionisation by all components of a cosmic ray shower and not just by the muons, reveals that the effect we have detected is certainly not inconsistent with laboratory observations of the LW absorption cross section. The analysis presented here, although very different from that of Erlykin et al., does come to the same conclusion that the events detected by AL were not caused by individual cosmic ray primaries - not because it is impossible on energetic grounds, but because events of the required energy are too infrequent for the 12 h-1 rate at which they were seen by the AL experiment. The present paper numerically models the effect of three different scenario changes to the primary GCR spectrum which all reproduce the required magnitude of the effect observed by AL. However, they cannot solely explain the observed delay in the peak effect which, if confirmed, would appear to open up a whole new and interesting area in the study of water oligomers and their effects on LW radiation. We argue that a technical artefact in the AL experiment is highly unlikely and that our initial observations merit both a wide-ranging follow-up experiment and more rigorous, self-consistent, three-dimensional radiative transfer modelling.

  10. Preliminary Investigation of Microdosimetric Track Structure Physics Models in Geant4-DNA and RITRACKS

    PubMed Central

    Bezak, Eva

    2015-01-01

    The major differences between the physics models in Geant4-DNA and RITRACKS Monte Carlo packages are investigated. Proton and electron ionisation interactions and electron excitation interactions in water are investigated in the current work. While these packages use similar semiempirical physics models for inelastic cross-sections, the implementation of these models is demonstrated to be significantly different. This is demonstrated in a simple Monte Carlo simulation designed to identify differences in interaction cross-sections. PMID:26124856

  11. Mixed-Field Dosimetry of a Fast Neutron Beam at the Portuguese Research Reactor for the Irradiation of Electronic Circuits - Measurements and Calculations

    NASA Astrophysics Data System (ADS)

    Fernandes, A. C.; Gonçalves, I. C.; Marques, J. G.; Santos, J.; Ramalho, A. J. G.; Osvay, M.

    2003-06-01

    The neutron and photon fields present at the Fast Neutron Beam of RPI were simulated with MCNP-4C and measured with activation foils, TLDs and ionisation chambers. In general, there is a good agreement between calculations and measurements, although the model overestimates the thermal neutron component. Aluminum oxide TLDs were found to be promising for monitoring the photon dose in actual irradiations of circuits.

  12. [Results of esophagogastroduodenoscopy many years after Chernobyl accident among those taking place in the liquidation of the results of the disaster].

    PubMed

    Kharchenko, V P; Sinev, Iu V; Ivanova, O V

    2002-01-01

    Gastroduodenal disorders were studied endoscopically for 5 years in 159 Chernobyl wreckers and were compared to subjects unexposed to ionising radiation. Upper gastroduodenal tract was examined with esophagogastroduodenoscopy to avoid additional radiation load. It was found that 8-12 years after irradiation, many examinees had gastroduodenal mucosa erosions the rate of which was persistently high. Incidences of malignant and benign tumors in the study and control groups did not differ significantly. PMID:12138798

  13. Preliminary testing of GaN-based dosimeters for electron beam radiotherapy.

    PubMed

    Ismail, A; Wang, R; Chaikh, A; Pittet, P; Balosso, J

    2015-07-01

    The response of an implantable in vivo dosimetric system based on gallium nitride radioluminescence was investigated for electron beam radiotherapy using ELEKTA SLi and VARIAN Clinac 2100 CD Linear Accelerators. A bi-channel method has been implemented for fibre background rejection. The percentage depth dose (PDD) profiles were measured in polymethyl methacrylate for 6, 12 and 18 MeV electron beams. The PDD results were in excellent agreement with those measured with reference to ionisation chambers. PMID:25813482

  14. Comparing different gas chromatographic methods for the quantification of bisphenol A (BPA) trace levels in paper and cardboard products from the market.

    PubMed

    Jurek, A; Leitner, E

    2015-01-01

    Bisphenol A (BPA; 4,4'-(propane-2,2-diyl)diphenol), a suspected endocrine disruptor with weak estrogenic activity, is used in a variety of consumer products, including paper and cardboard products used as food contact materials. The present study compared four different gas chromatographic methods for the analysis of BPA in paper and cardboard food packages. Eighteen different food packages were extracted and BPA was determined using two different derivatisation reactions--trimethylsilylation with N,O-bis(trimethylsilyl) trifluoroacetamide (BSTFA) and halide alkylation with pentafluorobenzoyl chloride (PFBOCl)--and four different separation and detection techniques. The BSTFA derivatives were quantified with (1) GC-MS in single-ion monitoring (SIM) mode with electron ionisation (EI-GC-MS) and (2) GC-MS/MS in multiple reaction monitoring (MRM) mode using electron ionisation (EI-GC-MS/MS); while the PFBOCl derivatives were quantified with (3) GC-MS using electron ionisation (EI-GC-MS) as well as (4) GC-MS with negative chemical ionisation (NCI-GC-MS). All developed methods showed good linearity (R(2) > 0.9938), precision (CV < 4.5% for reproducibility; CV < 2.2% for repeatability) and sensitivity, with limits of detection (LODs) between 0.02 µg kg(-1) for the pentafluorobenzoyl derivatives measured with the NCI-GC-MS method and 6 µg kg(-1) for the pentafluorobenzoyl derivatives determined with EI-GC-MS. Levels of BPA in the samples were in agreement for all methods, ranging from values below the limit of quantitation (LOQ) to 11.9 mg kg(-1) paper. In a last step, the maximum potential migration into food products was calculated for all tested paper and cardboard samples, assuming a 'worst case' scenario of 100% migration. PMID:26029846

  15. Reionisation and High-Redshift Galaxies: The View from Quasar Absorption Lines

    NASA Astrophysics Data System (ADS)

    Becker, George D.; Bolton, James S.; Lidz, Adam

    2015-12-01

    Determining when and how the first galaxies reionised the intergalactic medium promises to shed light on both the nature of the first objects and the cosmic history of baryons. Towards this goal, quasar absorption lines play a unique role by probing the properties of diffuse gas on galactic and intergalactic scales. In this review, we examine the multiple ways in which absorption lines trace the connection between galaxies and the intergalactic medium near the reionisation epoch. We first describe how the Ly α forest is used to determine the intensity of the ionising ultraviolet background and the global ionising emissivity budget. Critically, these measurements reflect the escaping ionising radiation from all galaxies, including those too faint to detect directly. We then discuss insights from metal absorption lines into reionisation-era galaxies and their surroundings. Current observations suggest a buildup of metals in the circumgalactic environments of galaxies over z ~ 6 to 5, although changes in ionisation will also affect the evolution of metal line properties. A substantial fraction of metal absorbers at these redshifts may trace relatively low-mass galaxies. Finally, we review constraints from the Ly α forest and quasar near zones on the timing of reionisation. Along with other probes of the high-redshift Universe, absorption line data are consistent with a relatively late end to reionisation (5.5 ≲ z ≲ 7); however, the constraints are still fairly week. Significant progress is expected to come through improved analysis techniques, increases in the number of known high-redshift quasars from optical and infrared sky surveys, large gains in sensitivity from next-generation observing facilities, and synergies with other probes of the reionisation era.

  16. Construction and testing of the scintillating fibre trackers for MICE

    SciTech Connect

    Fish, Aron

    2009-09-01

    The discovery of neutrino mass through experimental evidence of neutrino oscillations at the end of the last century has provided the first proof that the Standard Model of particle physics is incomplete. To be able to extend the Standard Model to incorporate massive neutrinos first requires many theoretical uncertainties surrounding the particle and its interactions to be understood. Therefore, a dedicated experimental programme is needed over the coming decades to provide precision measurements of the neutrino oscillation parameters and also a possible measurement of CP violation in the lepton sector, which could have astrophysical consequences. An intense source of neutrinos is required to achieve these precision measurements and the leading contender proposed to provide this neutrino beam, is the Neutrino Factory. Before a Neutrino Factory facility can be realised, a number of technological challenges need to be evaluated and understood first. One of which, is reduce the large phase space volume (emittance) of the initial muon beam, which is eventually stored and through decay provides the neutrino beam. Ionisation cooling is the chosen method to achieve this and the Muon Ionisation Cooling Experiment (MICE) at Rutherford Laboratory in the UK, is required to demonstrate ionisation cooling and its feasibility for a Neutrino Factory. To demonstrate ionisation cooling, a section of a cooling channel will be constructed and single-particle measurements of emittance of a muon beam before and after the cooling channel from particle spectrometers will be compared. To measure emittance accurately requires precision measurements of the momenta and spatial coordinates at the spectrometers by tracking devices in a uniform magnetic field. The focus of this thesis is based around the construction and testing of the MICE tracker(s), including a study of its simulated performance and also construction and testing of a prototype.

  17. Modelling the martian cosmic radiation environment

    NASA Astrophysics Data System (ADS)

    Dartnell, L. R.; Desorgher, L.; Ward, J. M.; Coates, A. J.

    2013-09-01

    The martian surface is no longer protected by a global magnetic field or substantial atmosphere and so is essentially unshielded to the flux of cosmic rays. This creates an ionising radiation field on the surface and subsurface that is hazardous to life and the operation of spacecraft instruments. Here we report the modelling approach used to characterise this complex and time-variable radiation environment and discuss the wider applications of the results generated.

  18. The application of the derivative IR-spectroscopy and HPLC-ESI-MS/MS in the analysis of archaeology resin

    NASA Astrophysics Data System (ADS)

    Zareva, S.; Kuleff, I.

    2010-07-01

    The applicability of the reducing-difference procedure for the interpretation of the conventional IR-spectroscopy as successful scientific technique for the analysis of ancient and modern resins has been demonstrated. The new temperature tool for modeling of the ancient resin samples has also been shown. The experimental infrared data are supported by the hydride approach of HPLC-MS-MS with ES-ionisation.

  19. Displays the Main Properties of the Elements in the Periodic Table

    Energy Science and Technology Software Center (ESTSC)

    1999-03-01

    Data Base on basic chemical and physical properties of the elements in the Mendeleyev Table. Example density electric and thermal conductivity, masses of isotopes and isomers, ionisation potential, etc. from H to Xc (A=112). The following modifications have been introduced: Names of high mass chemical elements have been updated accordingly to recent standard naming Crystallographic data has been improved and adapted to the new nomenclature.

  20. Connecting low- and high-mass star formation: the intermediate-mass protostar IRAS 05373+2349 VLA 2

    NASA Astrophysics Data System (ADS)

    Brown, G. M.; Johnston, K. G.; Hoare, M. G.; Lumsden, S. L.

    2016-08-01

    Until recently, there have been few studies of the protostellar evolution of intermediate-mass (IM) stars, which may bridge the low-and high-mass regimes. This paper aims to investigate whether the properties of an IM protostar within the IRAS 05373+2349 embedded cluster are similar to that of low- and/or high-mass protostars. We carried out Very Large Array as well as Combined Array for Research in Millimeter Astronomy continuum and 12CO(J=1-0) observations, which uncover seven radio continuum sources (VLA 1-7). The spectral index of VLA 2, associated with the IM protostar is consistent with an ionised stellar wind or jet. The source VLA 3 is coincident with previously observed H2 emission line objects aligned in the north-south direction (P.A. -20 to -12°), which may be either an ionised jet emanating from VLA 2 or (shock-)ionised cavity walls in the large-scale outflow from VLA 2. The position angle between VLA 2 and 3 is slightly misaligned with the large-scale outflow we map at ˜5-arcsec resolution in 12CO (P.A. ˜30°), which in the case of a jet suggests precession. The emission from the mm core associated with VLA 2 is also detected; we estimate its mass to be 12-23 M⊙, depending on the contribution from ionised gas. Furthermore, the large-scale outflow has properties intermediate between outflows from low- and high-mass young stars. Therefore, we conclude that the IM protostar within IRAS 05373+2349 is phenomenologically as well as quantitatively intermediate between the low- and high-mass domains.